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Journal articles on the topic 'Cerro de Pasco Corporation (Peru)'

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Published: 4 June 2021

Last updated: 6 February 2022

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1

Melton, C. A., D. C. Hughes, D. L. Page, and M. S. Phillips. "Temporal multispectral and 3D analysis of Cerro de Pasco, Peru." Science of The Total Environment 706 (March 2020): 135640. http://dx.doi.org/10.1016/j.scitotenv.2019.135640.

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2

Tácunan Bonifacio, Santiago. "Contaminación ambiental en el valle del Mantaro. Informe médico (La Oroya, 1926)." Investigaciones Sociales 16, no. 29 (June 11, 2014): 75–88. http://dx.doi.org/10.15381/is.v16i29.7710.

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Este trabajo analiza uno de los primeros informes médicos de principios del siglo xx que pone en evidencia la contaminación medio ambiental producida por la empresa minera Cerro de Pasco Copper Corporation en La Oroya (Valle del Mantaro, 1926).

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3

Niederschlag, Elke, and Heinrich Siemes. "Influence of Initial Texture, Temperature and Total Strain on the Texture Development of Polycrystalline Pyrrhotite Ores in Deformation Experiments." Textures and Microstructures 28, no. 1-2 (January 1, 1996): 129–48. http://dx.doi.org/10.1155/tsm.28.129.

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The development of the crystallographic preferred orientation (texture) of polycrystalline pyrrhotite from Sullivan mine, Canada, and Cerro de Pasco, Peru was determined by neutron texture analyses before and after experimental deformation. The pyrrhotite ore from Sullivan has an initial texture with a distinct c-axis maximum perpendicular to the foliation whereas the ore from Cerro de Pasco shows a weak and moreover inhomogeneous texture within the specimen.The deformation texture and deformation behaviour of samples from Sullivan were investigated as a function of temperature, total strain and the angle between the compression axis and the initial c-axis maximum. The deformation textures show the influence of different activated glide modes as a function of the compression direction and temperature. Investigations of the deformation texture and deformation behaviour of samples from Cerro de Pasco were carried out as a function of temperature, total strain and strain rate. The inhomogeneous texture of the starting material did not allow to draw conclusions about the texture development as a function of strain rate and temperature. Nevertheless the preferred orientation of the c-axes parallel to the compression axis becomes more evident with increasing total strain.

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4

Vagshal, D. S., and S. D. Belyaev. "Self-potential anomalies in Cerro de Pasco and Hualgayoc areas (Peru) revisited." Geophysical Prospecting 49, no. 1 (January 2001): 151–54. http://dx.doi.org/10.1046/j.1365-2478.2001.00232.x.

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5

Baumgartner, R., L. Fontbote, and T. Vennemann. "Mineral Zoning and Geochemistry of Epithermal Polymetallic Zn-Pb-Ag-Cu-Bi Mineralization at Cerro de Pasco, Peru." Economic Geology 103, no. 3 (May 1, 2008): 493–537. http://dx.doi.org/10.2113/gsecongeo.103.3.493.

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6

Deustua, Jose. "Routes, Roads, and Silver Trade in Cerro de Pasco, 1820-1860: The Internal Market in Nineteenth-Century Peru." Hispanic American Historical Review 74, no. 1 (February 1994): 1. http://dx.doi.org/10.2307/2517425.

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7

Deustua, José. "Routes, Roads, and Silver Trade in Cerro de Pasco, 1820-1860: The Internal Market in Nineteenth-Century Peru." Hispanic American Historical Review 74, no. 1 (February 1, 1994): 1–31. http://dx.doi.org/10.1215/00182168-74.1.001.

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8

Leon-Velarde, F., M. A. Ramos, J. A. Hernandez, D. De Idiaquez, L. S. Munoz, A. Gaffo, S. Cordova, D. Durand, and C. Monge. "The role of menopause in the development of chronic mountain sickness." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272, no. 1 (January 1, 1997): R90—R94. http://dx.doi.org/10.1152/ajpregu.1997.272.1.r90.

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The objective of this study was to investigate the role of menopause in the appearance of the physiopathological sequence that leads to chronic mountain sickness (CMS) in a high-altitude female population. The females studied are 30-54 yr old (n = 152) and have permanent residence in Cerro de Pasco (Pasco, Peru; 4,300 m). The sample was divided into postmenopausal and premenopausal groups for comparison. Blood oxygen saturation (SaO2), excessive erythrocytosis [EE, measured by the level of hematocrit (Het)], peak expiratory flow rates (PEFR), and a score that represents the main signs and symptoms of CMS (CMSscore) were measured. Postmenopausal women had higher Het (50.2 +/- 4.04 vs. 47.4 +/- 4.13%, P < 0.001), lower SaO2 (81.9 +/- 4.12 vs. 84.7 +/- 3.14%, P < 0.001) and PEFR values (489 +/- 101 vs. 534 +/- 90 l/min, P < 0.02), and slightly higher CMSscore (19.1 +/- 3.37 vs. 17.9 +/- 3.48, P < 0.06) than premenopausal women. The prevalence of women with EE (EE = Hct > 56%) was found to be 8.8%. Forty-five percent of the postmenopausal subjects presented a high CMSscore (> 21), whereas only 22% of the premenopausal subjects presented this high value (P < 0.02). We can therefore conclude that menopause may represent a contributing factor for the development of CMS.

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9

Appenzeller, O., T. Minko, C. Qualls, V. Pozharov, J. Gamboa, A. Gamboa, and Y. Wang. "Migraine in the Andes and Headache at Sea Level." Cephalalgia 25, no. 12 (December 2005): 1117–21. http://dx.doi.org/10.1111/j.1468-2982.2005.00973.x.

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In Cerro de Pasco (CP), Peru (altitude 4338 m) 24% of men have migraine with aura. We studied 30 men. Twenty CP natives, examined in CP, were rated using a chronic mountain sickness (CMS) score to separate controls (10) from those with CMS (10), a maladaptation syndrome in natives to altitude which includes severe, recurring headache. We collected white cells in CP and, from the same men, within 1 h of arrival in Lima (150 m above sea level). Ten normal US men volunteered white cells for comparison. After RNA extraction we assessed gene expression by reverse transcription-polymerase chain reaction. Low ATP1A1 subunit of the ATPase gene mRNA expression in CP was correlated with headache ( P = 0.002), acral paraesthesias ( P = 0.004) and CMS score ( P < 0.001). ATP1A1 subunit expression was increased in all Andeans in Lima ( P < 0.001). There were no differences between Andean controls in Lima and US controls. Manipulation of Na+/K+ATPase could offer relief for migraineurs at sea level.

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10

Tymko, Michael M., Ryan L. Hoiland, Joshua C. Tremblay, Mike Stembridge, Tony G. Dawkins, Geoff B. Coombs, Alexander Patrician, et al. "The 2018 Global Research Expedition on Altitude Related Chronic Health (Global REACH) to Cerro de Pasco, Peru: an Experimental Overview." Experimental Physiology 106, no. 1 (May 6, 2020): 86–103. http://dx.doi.org/10.1113/ep088350.

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11

Dold, Bernhard, Cheikh Wade, and Lluis Fontboté. "Water management for acid mine drainage control at the polymetallic Zn–Pb–(Ag–Bi–Cu) deposit Cerro de Pasco, Peru." Journal of Geochemical Exploration 100, no. 2-3 (February 2009): 133–41. http://dx.doi.org/10.1016/j.gexplo.2008.05.002.

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12

Rottier, Bertrand, Kalin Kouzmanov, Vincent Casanova, Anne-Sophie Bouvier, Lukas P. Baumgartner, Markus Wälle, and Lluís Fontboté. "Mineralized breccia clasts: a window into hidden porphyry-type mineralization underlying the epithermal polymetallic deposit of Cerro de Pasco (Peru)." Mineralium Deposita 53, no. 7 (January 2, 2018): 919–46. http://dx.doi.org/10.1007/s00126-017-0786-9.

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13

Wade, Cheikh, Bernhard Dold, and Lluis Fontboté. "GEOCHEMISTRY AND MINERALOGY OF THE QUIULACOCHA TAILINGS IMPOUNDMENT FROM THE POLYMETALLIC Zn-Pb-(Ag-Bi-Cu) DEPOSIT CERRO DE PASCO, PERU." Journal American Society of Mining and Reclamation 2006, no. 2 (June 30, 2006): 2198–206. http://dx.doi.org/10.21000/jasmr06022198.

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14

Molloy, James B., Donald T. Rodbell, David P. Gillikin, and Kurt T. Hollocher. "Citizen science campaign reveals widespread fallout of contaminated dust from mining activities in the central Peruvian Andes." Geology 48, no. 7 (April 27, 2020): 678–82. http://dx.doi.org/10.1130/g47096.1.

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Abstract Inadequate management of mine tailings at Cerro de Pasco, one of Peru’s largest mining complexes, has resulted in elevated concentrations of Pb, As, Cu, Zn, and Ag in surface soil horizons across the Junín Plain, central Peru. During June 2016, in response to local concern over mine contamination, teams of local citizens armed with sample bags, plastic trowels, and GPS receivers acquired 385 surface soil samples and 9 plant samples from agricultural lands from an area ∼1000 km2 on the Junín Plain. Metal concentrations were determined by acid digestion and inductively coupled plasma–mass spectrometry, and results revealed elevated levels of Pb, As, Cu, Zn, and Ag in all samples within a 10 km radius of the center of mining activities, and measurable contamination at least 30 km to the south-southwest, in the direction of prevailing winds. Dust traps emplaced for a 12 month period confirmed that contamination is ongoing. High metal concentrations in grasses growing on contaminated soils revealed that a portion of the total metal contamination is removed from the soil and held in grass tissue, where it can be ingested by graminivores, especially llama, alpaca, and sheep, thereby entering the human food supply.

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15

Rottier, Bertrand, Kalin Kouzmanov, Anne-Sophie Bouvier, Lukas P. Baumgartner, Markus Wälle, Hervé Rezeau, Ronner Bendezú, and Lluís Fontboté. "Heterogeneous melt and hypersaline liquid inclusions in shallow porphyry type mineralization as markers of the magmatic-hydrothermal transition (Cerro de Pasco district, Peru)." Chemical Geology 447 (December 2016): 93–116. http://dx.doi.org/10.1016/j.chemgeo.2016.10.032.

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16

Baumgartner, R., L. Fontbote, R. Spikings, M. Ovtcharova, U. Schaltegger, J. Schneider, L. Page, and M. Gutjahr. "Bracketing the Age of Magmatic-Hydrothermal Activity at the Cerro de Pasco Epithermal Polymetallic Deposit, Central Peru: A U-Pb and 40Ar/39Ar Study." Economic Geology 104, no. 4 (July 1, 2009): 479–504. http://dx.doi.org/10.2113/gsecongeo.104.4.479.

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17

Rottier, B., K. Kouzmanov, M. Wälle, R. Bendezú, and L. Fontboté. "Sulfide Replacement Processes Revealed by Textural and LA-ICP-MS Trace Element Analyses: Example from the Early Mineralization Stages at Cerro de Pasco, Peru." Economic Geology 111, no. 6 (June 17, 2016): 1347–67. http://dx.doi.org/10.2113/econgeo.111.6.1347.

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18

Smuda, Jochen, Bernhard Dold, Kurt Friese, and Peter Morgenstern. "GEOCHEMISTRY AND SECONDARY MINERALOGY AT THE SULFIDE-RICH EXCELSIOR WASTE ROCK DUMP FROM THE POLYMETALLIC Zn-Pb-(Ag-Bi-Cu) MINERALIZATION CERRO DE PASCO, PERU." Journal American Society of Mining and Reclamation 2006, no. 2 (June 30, 2006): 2084–89. http://dx.doi.org/10.21000/jasmr06022084.

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19

Moore, L. G., P. Brodeur, O. Chumbe, J. D'Brot, S. Hofmeister, and C. Monge. "Maternal hypoxic ventilatory response, ventilation, and infant birth weight at 4,300 m." Journal of Applied Physiology 60, no. 4 (April 1, 1986): 1401–6. http://dx.doi.org/10.1152/jappl.1986.60.4.1401.

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To test the hypothesis that increased hypoxic ventilatory responsiveness (HVR) raised maternal ventilation and arterial oxygenation during high-altitude pregnancy and related to the birth weight of the offspring, we studied 21 residents of Cerro de Pasco, Peru (4,300 m), while eight of them were 36 +/- 0 wk pregnant and 15 of them 13 +/- 0 wk postpartum. HVR was low in the nonpregnant women (mean +/- SE shape parameter A = 23 +/- 8) but increased nearly fourfold with pregnancy (A = 87 +/- 17). The increase in HVR appeared to account for the 25% rise in resting ventilation with pregnancy (delta VE observed = 2.4 +/- 0.7 l/min BTPS vs. delta VE predicted from delta HVR = 2.6 +/- 1.7 l/min BTPS, P = NS). Hyperoxia decreased ventilation in the pregnant women (P less than 0.01) to levels similar to those measured when nonpregnant. The increased ventilation of pregnancy raised arterial O2 saturation (SaO2) from 83 +/- 1 to 87 +/- 0%, and SaO2 was correlated positively with HVR in the pregnant women. The rise in SaO2 compensated for a 0.9 g/100 ml decrease in hemoglobin concentration to preserve arterial O2 content at levels present when nonpregnant. Cardiac output in the 36th wk of pregnancy did not differ significantly from values measured postpartum. The increase in HVR correlated positively with infant birth weight. An increase in HVR may be an important contributor to increased maternal ventilation with pregnancy and infant birth weight at high altitude.

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20

West, John B. "Joseph Barcroft's studies of high-altitude physiology." American Journal of Physiology-Lung Cellular and Molecular Physiology 305, no. 8 (October 15, 2013): L523—L529. http://dx.doi.org/10.1152/ajplung.00176.2013.

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Joseph Barcroft (1872–1947) was an eminent British physiologist who made contributions to many areas. Some of his studies at high altitude and related topics are reviewed here. In a remarkable experiment he spent 6 days in a small sealed room while the oxygen concentration of the air gradually fell, simulating an ascent to an altitude of nearly 5,500 m. The study was prompted by earlier reports by J. S. Haldane that the lung secreted oxygen at high altitude. Barcroft tested this by having blood removed from an exposed radial artery during both rest and exercise. No evidence for oxygen secretion was found, and the combination of 6 days incarceration and the loss of an artery was heroic. To obtain more data, Barcroft organized an expedition to Cerro de Pasco, Peru, altitude 4,300 m, that included investigators from both Cambridge, UK and Harvard. Again oxygen secretion was ruled out. The protocol included neuropsychometric measurements, and Barcroft famously concluded that all dwellers at high altitude are persons of impaired physical and mental powers, an assertion that has been hotly debated. Another colorful experiment in a low-pressure chamber involved reducing the pressure below that at the summit of Mt. Everest but giving the subjects 100% oxygen to breathe while exercising as a climber would on Everest. The conclusion was that it would be possible to reach the summit while breathing 100% oxygen. Barcroft was exceptional for his self-experimentation under hazardous conditions.

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21

Villafuerte, Francisco C., José Luis Macarlupú, Cecilia Anza-Ramírez, Daniela Corrales-Melgar, Gustavo Vizcardo-Galindo, Noemí Corante, and Fabiola León-Velarde. "Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness." Journal of Applied Physiology 117, no. 11 (December 1, 2014): 1356–62. http://dx.doi.org/10.1152/japplphysiol.00619.2014.

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Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.

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22

Bilo, Grzegorz, Lorenzo Acone, Cecilia Anza-Ramírez, José Luis Macarlupú, Davide Soranna, Antonella Zambon, Gustavo Vizcardo-Galindo, Martino F. Pengo, Francisco C. Villafuerte, and Gianfranco Parati. "Office and Ambulatory Arterial Hypertension in Highlanders." Hypertension 76, no. 6 (December 2020): 1962–70. http://dx.doi.org/10.1161/hypertensionaha.120.16010.

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Millions of people worldwide live at high altitude, being chronically exposed to hypobaric hypoxia. Hypertension is a major cardiovascular risk factor but data on its prevalence and determinants in highlanders are limited, and systematic studies with ambulatory blood pressure monitoring are not available. Aim of this study was to assess the prevalence of clinic and ambulatory hypertension and the associated factors in a sample of Andean highlanders. Hypertension prevalence and phenotypes were assessed with office and ambulatory blood pressure measurement in a sample of adults living in Cerro de Pasco, Peru (altitude 4340 m). Basic clinical data, blood oxygen saturation, hematocrit, and Qinghai Chronic Mountain Sickness score were obtained. Participants were classified according to the presence of excessive erythrocytosis and chronic mountain sickness diagnosis. Data of 289 participants (143 women, 146 men, mean age 38.3 years) were analyzed. Office hypertension was present in 20 (7%) participants, while ambulatory hypertension was found in 58 (20%) participants. Masked hypertension was common (15%), and white coat hypertension was rare (2%). Among participants with ambulatory hypertension, the most prevalent phenotypes included isolated nocturnal hypertension, isolated diastolic hypertension, and systodiastolic hypertension. Ambulatory hypertension was associated with male gender, age, overweight/obesity, 24-hour heart rate, and excessive erythrocytosis. Prevalence of hypertension among Andean highlanders may be significantly underestimated when based on conventional blood pressure measurements, due to the high prevalence of masked hypertension. In highlanders, ambulatory hypertension may be independently associated with excessive erythrocytosis.

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23

Wisskirchen, Christian, Bernhard Dold, Kurt Friese, and Walter Glaesser. "ELEMENT DISTRIBUTION IN WATER AND SEDIMENTS OF AN ACID MINE DRAINAGE DISCHARGE LAKE (pH ~1) OF THE Zn-Pb(-Ag-Bi-Cu) DEPOSIT, CERRO DE PASCO (PERU)." Journal American Society of Mining and Reclamation 2006, no. 2 (June 30, 2006): 2470–79. http://dx.doi.org/10.21000/jasmr06022470.

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24

Rottier, B., K. Kouzmanov, V. Casanova, M. Wälle, and L. Fontboté. "Cyclic Dilution of Magmatic Metal-Rich Hypersaline Fluids by Magmatic Low-Salinity Fluid: A Major Process Generating the Giant Epithermal Polymetallic Deposit of Cerro de Pasco, Peru." Economic Geology 113, no. 4 (June 1, 2018): 825–56. http://dx.doi.org/10.5382/econgeo.2018.4573.

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25

Rottier, Bertrand, Kalin Kouzmanov, Maria Ovtcharova, Alexey Ulianov, Markus Wälle, David Selby, and Lluís Fontboté. "Multiple rejuvenation episodes of a silicic magma reservoir at the origin of the large diatreme-dome complex and porphyry-type mineralization events at Cerro de Pasco (Peru)." Lithos 376-377 (December 2020): 105766. http://dx.doi.org/10.1016/j.lithos.2020.105766.

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26

Rottier, Bertrand, Kalin Kouzmanov, Vincent Casanova, Anne-Sophie Bouvier, Lukas P. Baumgartner, Markus Wälle, and Lluís Fontboté. "Tracking fluid mixing in epithermal deposits – Insights from in-situ δ18O and trace element composition of hydrothermal quartz from the giant Cerro de Pasco polymetallic deposit, Peru." Chemical Geology 576 (August 2021): 120277. http://dx.doi.org/10.1016/j.chemgeo.2021.120277.

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27

Smuda, Jochen, Bernhard Dold, Kurt Friese, Peter Morgenstern, and Walter Glaesser. "Mineralogical and geochemical study of element mobility at the sulfide-rich Excelsior waste rock dump from the polymetallic Zn–Pb–(Ag–Bi–Cu) deposit, Cerro de Pasco, Peru." Journal of Geochemical Exploration 92, no. 2-3 (February 2007): 97–110. http://dx.doi.org/10.1016/j.gexplo.2006.08.001.

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28

Gonzales, Gustavo F., Manuel Gasco, Vilma Tapia, and Cynthia Gonzales-Castañeda. "High serum testosterone levels are associated with excessive erythrocytosis of chronic mountain sickness in men." American Journal of Physiology-Endocrinology and Metabolism 296, no. 6 (June 2009): E1319—E1325. http://dx.doi.org/10.1152/ajpendo.90940.2008.

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Chronic mountain sickness (CMS) is characterized by excessive erythrocytosis (EE) secondary to hypoventilation. Erythropoietin (Epo) and testosterone regulate erythrocyte production. Low thyroid hormone levels are also associated to hypoventilation. Hence, these hormones can play a role in etiopathogeny of EE. The purpose of this study was to elucidate the effect of sexual and thyroid hormones and Epo in residents from Lima (150 m) and Cerro de Pasco (4,340 m), Peru, and the response to human chorionic gonadotrophin stimulation (hCG). Three groups, one at low altitude and two at high altitude [1 with hemoglobin values >16–21 g/dl and the second with Hb ≥21 g/dl (EE)], were studied. hCG was administered intramuscularly in a single dose (1,000 IU), and blood samples were obtained at 0, 6, 12, 24, 48, and 72 h after injection. High-altitude natives present similar levels of gonadotropins and thyroid hormones but lower dehydroepiandrosterone sulphate (DHEAS) levels ( P < 0.01) and greater Epo ( P < 0.01), 17α-hydroxyprogesterone ( P < 0.01), and testosterone levels ( P < 0.01) than those at 150 m. Serum testosterone levels (524.13 ± 55.91 μg/dl vs. 328.14 ± 53.23 ng/dl, means ± SE; P < 0.05) and testosterone/DHEAS ratios are higher (7.98 ± 1.1 vs. 3.65 ± 1.1; P < 0.01) and DHEAS levels lower in the EE group (83.85 ± 14.60 μg/dl vs. 148.95 ± 19.11 ug/dl; P < 0.05), whereas Epo was not further affected. Testosterone levels were highest and DHEAS levels lowest in the EE group at all times after hCG stimulation. In conclusion, high androgen activity could be involved in the etiopathogeny of CMS. This evidence provides an opportunity to develop new therapeutic strategies.

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Steele, Andrew R., Michael M. Tymko, Victoria L. Meah, Lydia L. Simpson, Christopher Gasho, Tony G. Dawkins, Francisco C. Villafuerte, et al. "Global REACH 2018: renal oxygen delivery is maintained during early acclimatization to 4,330 m." American Journal of Physiology-Renal Physiology 319, no. 6 (December 1, 2020): F1081—F1089. http://dx.doi.org/10.1152/ajprenal.00372.2020.

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Early acclimatization to high altitude is characterized by various respiratory, hematological, and cardiovascular adaptations that serve to restore oxygen delivery to tissue. However, less is understood about renal function and the role of renal oxygen delivery (RDO2) during high altitude acclimatization. We hypothesized that 1) RDO2 would be reduced after 12 h of high altitude exposure (high altitude day 1) but restored to sea level values after 1 wk (high altitude day 7) and 2) RDO2 would be associated with renal reactivity, an index of acid-base compensation at high altitude. Twenty-four healthy lowlander participants were tested at sea level (344 m, Kelowna, BC, Canada) and on day 1 and day 7 at high altitude (4,330 m, Cerro de Pasco, Peru). Cardiac output, renal blood flow, and arterial and venous blood sampling for renin-angiotensin-aldosterone system hormones and NH2-terminal pro-B-type natriuretic peptides were collected at each time point. Renal reactivity was calculated as follows: (Δarterial bicarbonate)/(Δarterial Pco2) between sea level and high altitude day 1 and sea level and high altitude day 7. The main findings were that 1) RDO2 was initially decreased at high altitude compared with sea level (ΔRDO2: −22 ± 17%, P < 0.001) but was restored to sea level values on high altitude day 7 (ΔRDO2: −6 ± 14%, P = 0.36). The observed improvements in RDO2 resulted from both changes in renal blood flow (Δ from high altitude day 1: +12 ± 11%, P = 0.008) and arterial oxygen content (Δ from high altitude day 1: +44.8 ± 17.7%, P = 0.006) and 2) renal reactivity was positively correlated with RDO2 on high altitude day 7 ( r = 0.70, P < 0.001) but not high altitude day 1 ( r = 0.26, P = 0.29). These findings characterize the temporal responses of renal function during early high altitude acclimatization and the influence of RDO2 in the regulation of acid-base balance.

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30

Steele, Andrew R., Michael M. Tymko, Victoria L. Meah, Lydia L. Simpson, Christopher Gasho, Tony G. Dawkins, Alexandra M. Williams, et al. "Global REACH 2018: volume regulation in high-altitude Andeans with and without chronic mountain sickness." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 321, no. 3 (September 1, 2021): R504—R512. http://dx.doi.org/10.1152/ajpregu.00102.2021.

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The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed NH2-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP) in Andean males without ( n = 14; age = 39 ± 11 yr) and with ( n = 10; age = 40 ± 12 yr) CMS at 4,330 m (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8 ± 7.9 ng/mL vs. CMS: 8.7 ± 5.4 ng/mL; P = 0.025) and plasma aldosterone concentration (non-CMS: 77.5 ± 35.5 pg/mL vs. CMS: 54.2 ± 28.9 pg/mL; P = 0.018) were lower in highlanders with CMS compared with non-CMS, whereas NT pro-BNP was not different between groups (non-CMS: 1394.9 ± 214.3 pg/mL vs. CMS: 1451.1 ± 327.8 pg/mL; P = 0.15). Highlanders had similar total blood volume (non-CMS: 90 ± 15 mL·kg−1 vs. CMS: 103 ± 18 mL·kg−1; P = 0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46 ± 10 mL·kg−1 vs. CMS: 66 ± 14 mL·kg−1; P < 0.01) and smaller plasma volume (non-CMS: 43 ± 7 mL·kg−1 vs. CMS: 35 ± 5 mL·kg−1; P = 0.03) compared with non-CMS. There were no differences in ePASP between groups (non-CMS: 32 ± 9 mmHg vs. CMS: 31 ± 8 mmHg; P = 0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r = −0.66; P < 0.01; non-CMS: r = −0.60; P = 0.022; CMS: r = −0.63; P = 0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high altitude, causing potentially greater polycythemia and clinical symptoms.

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Tremblay, Joshua C., Geoff B. Coombs, Connor A. Howe, Gustavo A. Vizcardo-Galindo, Rómulo J. Figueroa-Mujíca, Daniela Bermudez, Michael M. Tymko, Francisco C. Villafuerte, Philip N. Ainslie, and Kyra E. Pyke. "Global Reach 2018: reduced flow-mediated dilation stimulated by sustained increases in shear stress in high-altitude excessive erythrocytosis." American Journal of Physiology-Heart and Circulatory Physiology 317, no. 5 (November 1, 2019): H991—H1001. http://dx.doi.org/10.1152/ajpheart.00316.2019.

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Excessive erythrocytosis [EE; hemoglobin concentration (Hb) ≥ 21 g/dL in adult men] is a maladaptive high-altitude pathology associated with increased cardiovascular risk and reduced reactive hyperemia flow-mediated dilation (FMD); however, whether a similar impairment occurs in response to more commonly encountered sustained increases in shear stress [sustained stimulus (SS)-FMD] over a range of overlapping stimuli is unknown. We characterized SS-FMD in response to handgrip exercise in Andeans with and without EE in Cerro de Pasco, Peru (4,330 m). Andean highlanders with EE ( n = 17, Hb = 23.2 ± 1.2 g/dL) and without EE ( n = 23, Hb = 18.7 ± 1.9 g/dL) performed 3 min of rhythmic handgrip exercise at 20, 35, and 50% of maximum voluntary contraction (MVC). Duplex ultrasound was used to continuously record blood velocity and diameter in the brachial artery, and blood viscosity was measured to accurately calculate shear stress. Although baseline shear stress did not differ, Andeans with EE had 22% lower shear stress than Andeans without at 50% MVC ( P = 0.004). At 35 and 50% MVC, SS-FMD was 2.1 ± 2.0 and 2.8 ± 2.7% in Andeans with EE compared with 4.1 ± 3.4 and 7.5 ± 4.5% in those without ( P = 0.048 and P < 0.001). The stimulus-response slope (∆shear stress vs. ∆diameter) was lower in Andeans with EE compared with Andeans without ( P = 0.028). This slope was inversely related to Hb in Andeans with EE ( r2 = 0.396, P = 0.007). A reduced SS-FMD in response to small muscle mass exercise in Andeans with EE indicates a generalized reduction in endothelial sensitivity to shear stress, which may contribute to increased cardiovascular risk in this population. NEW & NOTEWORTHY High-altitude excessive erythrocytosis (EE; hemoglobin concentration ≥ 21 g/dL) is a maladaptation to chronic hypoxia exposure and is associated with increased cardiovascular risk. We examined flow-mediated dilation (FMD) in response to sustained elevations in shear stress achieved using progressive handgrip exercise [sustained stimulus (SS)-FMD] in Andean highlanders with and without EE at 4,330 m. Andeans with EE demonstrated lower SS-FMD compared with those without. Heightened hemoglobin concentration was related to lower SS-FMD in Andeans with EE.

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Tremblay, Joshua C. "Shear stress and flow-mediated dilation in the normoxic and hypoxic human." Applied Physiology, Nutrition, and Metabolism 44, no. 8 (August 2019): 902. http://dx.doi.org/10.1139/apnm-2019-0292.

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The endothelium is a single cell layer that plays a critical role in determining the health and function of blood vessels. Endothelial function is shaped by shear stress, the frictional force exerted by the speed of blood flow, and the thickness (viscosity) of the blood. Exposure to shear stress that reverses direction back-and-forth impairs endothelial function in young men. Whether women are equally susceptible to this perturbation and the isolated impact of a low level of shear stress with and without reversal of shear had not been investigated. Hypoxia, the low levels of oxygen that are experienced at high altitude, has been shown to influence flow reversal and impair endothelial function. However, no previous study had accounted for the changes in blood thickness, and hence shear stress that occur at high altitude. This may be especially important in the context of excessive erythrocytosis, a high-altitude disease characterized by exceptionally thick blood and increased cardiovascular risk. This thesis examined (i) whether there are sex differences in the impact of exposure to low and reversing shear stress on endothelial function; (ii) whether isolated low shear stress impairs endothelial function; (iii) the impact of reversing shear stress on endothelial function in short-term exposure to low levels of oxygen and after trekking to 5050 m in the Himalayas; and (iv) the role of high levels of blood viscosity on endothelial function in high-altitude natives in Cerro de Pasco, Peru (4330 m), with excessive erythrocytosis. We identified that (i) premenopausal women have some protection against reductions in endothelial function after being exposed to reversing shear stress; (ii) isolated low shear stress impaired endothelial function; (iii) short-term exposure to low levels of oxygen and sustained high-altitude exposure reduced endothelial function, while superimposing reversing shear stress had no effect; and (iv) high levels of hemoglobin and blood viscosity contributed to lower endothelial function in Andean high-altitude natives with excessive erythrocytosis. Altogether, this dissertation advances our understanding of how the components of shear stress (the pattern, magnitude, and blood viscosity) impact endothelial function in humans under normoxic (normal levels of oxygen) and hypoxic (low levels of oxygen, such as high-altitude) conditions.

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Wang, Xunde, David Callacondo, Jose Rojas, Jose Quesada-Olarte, Alan T. Remaley, Irina Maric, John F. Tisdale, Fabiola Leon-Velarde, Francisco Villafuerte, and Matthew Hsieh. "Erythrocytosis in Chronic Mountain Sickness (CMS) in Andeans." Blood 124, no. 21 (December 6, 2014): 4873. http://dx.doi.org/10.1182/blood.v124.21.4873.4873.

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Abstract Introduction: Chronic mountain sickness (CMS) was first described as erythrocytosis of high altitude among Andean high altitude dwellers. Later description of this condition quickly implicated increasing age and increasing hematocrit as the main drivers for many physiological changes. Now CMS is a full clinical syndrome, and the severity is based on scoring of symptoms, physical examination signs, and hemoglobin (Hb) levels. Protective alleles in EPAS1 and EGLN1 have been associated with less erythrocytosis in Tibetans. Recently, SNPs in ANP32D and SENP1 leading to increases in their expression have been reported in CMS due to excessive hypoxia response. Fetal hemoglobin (HbF), having higher oxygen affinity than adult Hb, has been tested in small number of participants. There was no difference in those with or without CMS. Thus we tested these genes and laboratory parameters in a larger Andean cohort. Methods: Healthy 153 adults and 32 children age ≥5 years old, born and lived in Cerro de Pasco, Peru (4338 m), enrolled in the study. Native residency was defined as living, eating, and sleeping in households in the study area, with total absences <1 year at lower altitudes (<3000 m), and being > 6 months at high altitude before the study entry. Blood sample for blood counts, hemoglobin electrophoresis, plasma erythropoietin (EPO), and brain natriuretic peptide (pro BNP) were tested. SNP identification was carried out by PCR and Sanger sequencing of the 4 candidate genes (EPAS1, EGLN1, ANP32D, and SENP1). Testing for JAK2 V617F was also performed. Results: 58 adults and no children had CMS. 52% of the participants belonged in the healthy group (CMS score ≤5), 24% in mild CMS (score 6-10), 12% moderate CMS (score 11-15), and 2.2% severe (score >15). The mean Hb level was lower in the healthy group, compared to the CMS groups (P<0.001). The entire group (n= 184) had normal levels of HbF, median value of 0.4% (range 0.2-1.9). There were no differences (P=0.9) between healthy and CMS participants, adults and children, or men and women. In the participants who had sufficient quantity of plasma, EPO and proBNP determinations were performed. Mean plasma EPO levels correlated negatively with increasing CMS score, but none was statistically significant (P=0.24). In contrast, proBNP levels were the lowest levels in healthy group (27.5±3.1 pg/mL) and highest in the mild CMS group (66.5±14.1 pg/mL). TableGroupHb (g/dL)EPO (mIU/mL)Pro BNP (pg/mL)Healthy (N=47)17.1 ± 0.217.7 ± 2.427.5 ± 3.1Mild CMS (N=30)20.6 ± 0.4*12.6 ± 1.666.5 ± 14.1**Moderate CMS (N=15)22.3 ± 0.4*11.2 ± 2.342.0 ± 9.1Severe CMS (N=2)22.5 ± 1.3*10.6 ± 2.747.5 ± 23.5 * P<0.001, compared to healthy group by one way ANOVA ** P=0.005, compared to healthy group by one way ANOVA Previous studies showed that high altitude dwellers in Tibet harbor protective SNPs in the EPAS1 (or HIF 2a) and EGLN1 (or PHD2). Thus we chose 26 men with the highest Hb and 13 individuals with normal Hb, and performed SNP sequencing for these 2 genes. There was no difference between the 2 groups in the EPAS1 gene; all had CC allele. The T content in EGLN1 was 69% in CMS, and 85% in the control group (odds ratio for C vs T, 2.4, P =0.14). Another recent report showed that other candidate genes may be associated with CMS. Sequencing of ANP32D (rs72644851) revealed that G content in 25 CMS participants was 64%, and 96% in 13 controls (odds ratio for G vs A, 14.06, P=0.002). The percent of G content in SENP1 (rs7963934) in CMS was 84%, and 100% in controls (odds ratio for G vs C, 10.6, P=0.045). Additionally, 15 of these participants with CMS had JAK2 V617F mutation analysis; all showed the wildtype allele. Conclusion: Compared to healthy adults, CMS participants had similar and normal HbF levels and statistically insignificant lower plasma EPO levels. Pro BNP levels were higher only in the mild CMS group. We confirmed the association between SNPs in ANP32D and SENP1 and CMS in Andeans. Furthermore, the protective SNPs present in the Tibetan population, EPAS1 or EGLN1, are not present in this population of Andeans, potentially explaining the increased prevalence in Andeans at high altitude. Disclosures No relevant conflicts of interest to declare.

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Cheney, E. S. "Structure and age of the Cerro de Pasco Cu-Zn-Pb-Ag deposit, Peru." Mineralium Deposita 26, no. 1 (April 1991). http://dx.doi.org/10.1007/bf00202357.

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"Analysis of water contamination in the mining zone of Cerro de Pasco, Peru using the grey clustering method." International Journal of Advanced Trends in Computer Science and Engineering 9, no. 5 (October 15, 2020): 8385–89. http://dx.doi.org/10.30534/ijatcse/2020/212952020.

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"Trabajo en equipo y desarrollo del pensamiento crítico en la formación docente en la Universidad Nacional Daniel Alcides Carrión, pasco, perú." Revista ECIPeru, January 15, 2019, 98–103. http://dx.doi.org/10.33017/reveciperu2010.0027/.

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Trabajo en equipo y desarrollo del pensamiento crítico en la formación docente en la Universidad Nacional Daniel Alcides Carrión, pasco, perú Team work and development of critical thinking in teacher training at the Daniel Alcides Carrion National University, pasco, peru Julio César Carhuaricra Meza Universidad Nacional Daniel Alcides Carrión, Edificio Estatal Nº 4, San Juan pampa, Cerro de pasco, pasco DOI: https://doi.org/10.33017/RevECIPeru2010.0027/ RESUMEN El trabajo en equipo (T. E.) y el desarrollo de pensamiento crítico (p. C.) son competencias que debemos promover en los estudiantes universitarios, como lo plantea el proyecto Tuning de América Latina. Guiado por tal demanda, nos propusimos determinar el nivel de influencia del primero (T. E.) sobre el segundo (p. C.) en el contexto de la formación docente. para ello, se ha elegido el tipo de estudio correlativo y explicativo, y respecto al diseño, se ha elegido el cuasiexperimental, con tratamientos múltiples y evaluaciones de pre test y post test. Asimismo, se ha considerado dos grupos: experimental y control. El universo lo constituyeron 753 alumnos y la muestra 60 alumnos. Las técnicas aplicadas fueron: para la muestra, no probabilística con población finita; para la recolección de datos, la encuesta y análisis documentario. La principal conclusión a la que ha llegado la investigación es que el trabajo en equipo influye favorablemente en el desarrollo del pensamiento crítico en la formación docente. Descriptores: trabajo en equipo, desarrollo del pensamiento crítico y formación docente. ABSTRACT Working in teams and the development of critical thinking are capabilities that we must promote in university students, as proposed by the latin america tuning project. Guided by such demand we set out to determine the influence of the first (t .e.) upon the second one (P.c.) in the context of teacher training. We have selected a correlative and explanatory study type, the design chosen is the quasi - experimental, with multiple treatments with evaluations of pre test and post test. at the same time, we considered two groups: experimental and control. The universe was constituted of 753 alumni and the sample of 60 alumni. The applied techniques were: for the samples, not probabilistic with finite population; for the data collection survey and documentary analysis. The main conclusion reached by this investigation is that teamwork influences favorably in the development of critical thinking in the teacher training. Keywords: work team, development of critical thinking and training teachers.

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Quiroga Agurto, Mauro, Elvira Leticia Zeballos Velásquez, and Felipe Americo Reyes Navarro. "Structural changes in clays subjected to heat treatment: an analysis by structural refinement using the Rietveld method." Revista Mexicana de Física 67, no. 6 Nov-Dec (September 24, 2021). http://dx.doi.org/10.31349/revmexfis.67.061602.

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Structural factors in clays influence their physical properties. Therefore, it is particularly important to understand the effects of heat treatment on the structure of the material during the ceramic process. In this work, we have analyzed clays from quarries in the Cerro de Pasco region, Peru, to evaluate their characteristics and the structural changes produced by heating, particularly in the interlaminar region. The samples were thermally treated between 150 oC and 800 oC with intervals of 50 oC. To evaluate the structural changes produced by temperature, X-ray diffraction were carried out before and after each heat treatment. The qualitative analysis of the measurements allowed to identify the mineralogical composition of the samples, finding phases of calcium montmorillonite, kaolinite, illite and quartz. The quantitative analysis by the Rietveld method found structural changes, particularly in the Ca-montmorillonite expansive clay. It was also possible to determine the decrease in the weight percentage of the kaolinite until the collapse of its structure between 450 °C and 500 °C. The illite presented greater thermal stability, with slight variations in its weight percentage during heat treatment, without compromising its structure. Although the quartz phase did not show relevant structure changes, it slightly increased its weight percentage with increasing temperature.

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Brewster, L. Madden, Hannah Fandl, Anthony Bain, Vinicius P. Garcia, Rachel Stone, Jared Greiner, Noah M. DeSouza, et al. "Abstract MP26: Endothelial-derived Microvesicles From Andean Highlanders With Excessive Erythrocytosis Induce A Deleterious Cardiomyocyte Phenotype." Hypertension 76, Suppl_1 (September 2020). http://dx.doi.org/10.1161/hyp.76.suppl_1.mp26.

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Background: Excessive erythrocytosis (EE), defined as Hb ≥21 g/dL in men and ≥19 g/dL in women, is a pathologic consequence of residing at high altitude (>2500 m) and is common in Andean highlanders. EE is associated with increased cardiovascular risk and cardiac dysfunction. Specifically, EE has been linked to congestive heart failure as well as right ventricular hypertrophy in high altitude dwellers. The mechanisms responsible for diminished cardiac function in adults with EE remain unclear. Endothelial microvesicles (EMVs) play an important role in mediating interaction between the vascular endothelium and cardiac function. The experimental aim of this study was to determine the effects of EMVs isolated from adults with EE on markers of cardiomyocyte fibrosis, hypertrophy and autophagy as well as endothelial nitric oxide synthase (eNOS). Methods: Twenty-four male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (Healthy; age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL) and 12 highlanders with EE (EE: 45±5 yr; 26.7±1.0; 24.4±0.4 g/dL). All subjects were non-obese, normotensive, normolipidemic and non-diabetic. EMVs (CD31+/CD42b-) were identified, enumerated, and isolated from plasma by flow cytometry. Human induced pluripotent stem cell cardiomyocytes were cultured and treated with EMVs from either healthy or EE men. Results: EMVs from EE men induced significantly greater expression of specific markers of fibrosis: TGF-β (91.1±4.0 vs 52.7±3.8 AU) and alpha-1 type I collagen (85.6±5.6 vs 59.7±4.8 AU) and hypertrophy: troponin T (41.4±2.0 vs 16.9±1.4 AU) and α-actinin (95.3±6.7 vs 62.4±5.0 AU) than EMVs from healthy men. Cell autophagy was not significantly affected by EE EMVs. Intercellular expression of phosphorylated eNOS at the primary activation site, Ser1177 (13.3±1.1 vs 18.9±1.2 AU), and inhibitory site, Thr495 (56.7±3.4 vs 40.8±2.7 AU), were ~35% lower and ~30% higher (both P<0.05), respectively, in cells treated with EMVs from EE compared with healthy men. Conclusions: These data indicate that EMVs from Andean highlanders with EE negatively affect cardiomyocyte function and, therefore, may contribute to the increased risk of heart failure and cardiac dysfunction associated with EE.

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Brewster, Madden, Anthony R. Bain, Vinicius P. Garcia, Hannah K. Fandl, Rachel Stone, Noah M. DeSouza, Jared J. Greiner, Michael M. Tymko, Francisco C. Villafuerte, and Philip N. Ainslie. "Abstract 14993: Dysfunctional Extracellular Microvesicles in Andean Highlanders With Excessive Erythrocytosis." Circulation 142, Suppl_3 (November 17, 2020). http://dx.doi.org/10.1161/circ.142.suppl_3.14993.

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Background: Chronic mountain sickness, a maladaptation to high altitude (>2,500 m) characterized by excessive erythrocytosis (EE) and often severe hypoxemia, is prevalent in Andean highlanders. EE increases the risk of cardiovascular events and contributes to vascular dysfunction. Circulating extracellular microvesicles (MVs) are key mediators of cardiovascular health and disease through their interaction with the vascular endothelium. The experimental aim of this study was to determine the effects of MVs isolated from adults with EE on endothelial cell inflammation, oxidative stress, apoptosis and nitric oxide (NO) production. Methods: Twenty-six male residents of Cerro de Pasco, Peru (4,340 m) were studied: 12 highlanders without EE (healthy; age: 40±4 yr; BMI: 26.4±1.7; Hb: 17.4±0.5 g/dL, SpO 2 : 86.9±1.0%) and 14 highlanders with EE (EE: 43±4 yr; 26.2±0.9; 24.4±0.4 g/dL; 79.7±1.6%). MVs were isolated from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with MVs from either healthy or EE men. Results: MVs from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8±2.7 vs 77.1±1.9 pg/mL) and IL-8 (62.0±2.7 vs 53.3±2.2 pg/mL) compared with MVs from healthy highlanders. Although intracellular expression of total NF-κB p65 (65.3±6.0 vs 74.9±7.8.9 AU) was not significantly affected, MVs from EE men resulted in ~25% higher (P<0.05) expression of p-NF-κB p65 (Ser536; active NF-κB) (173.6±14.3 vs 132.8±12.2 AU). Additionally, cell expression of the anti-inflammatory miR-146a and miR-181b were significantly suppressed by EE MVs. Cell oxidative stress and apoptotic susceptibility were not significantly affected by MVs from EE men. However, eNOS activation (231.3±15.5 vs 286.6±23.0 AU) and NO production (8.3±0.6 vs 10.7±0.7 μM/L) were significantly lower in cells treated with MVs from EE vs healthy men. Conclusion: Increased inflammation and decreased eNOS activity and NO production renders the vascular endothelium highly susceptible to atherosclerosis and thrombosis. Andean highlanders with EE exhibit dysfunctional circulating extracellular MVs that induce a proatherogenic endothelial phenotype contributing to their increased cardiovascular risk.

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