Academic literature on the topic 'Cement germ'

SummaryGerm plasm, a cytoplasmic factor of germline cell differentiation, is suggested to be a perspective tool for in vitro meiotic differentiation. To discriminate between the: (1) germ plasm-related structures (GPRS) involved in meiosis triggering; and (2) GPRS involved in the germ plasm storage phase, we investigated gametogenesis in the marine medaka Oryzias melastigma. The GPRS of the mitosis-to-meiosis period are similar in males and females. In both sexes, five events typically occur: (1) turning of the primary Vasa-positive germ plasm granules into the Vasa-positive intermitochondrial cement (IMC); (2) aggregation of some mitochondria by IMC followed by arising of mitochondrial clusters; (3) intramitochondrial localization of IMC-originated Vasa; followed by (4) mitochondrial cluster degradation; and (5) intranuclear localization of Vasa followed by this protein entering the nuclei (gonial cells) and synaptonemal complexes (zygotene–pachytene meiotic cells). In post-zygotene/pachytene gametogenesis, the GPRS are sex specific; the Vasa-positive chromatoid bodies are found during spermatogenesis, but oogenesis is characterized by secondary arising of Vasa-positive germ plasm granules followed by secondary formation and degradation of mitochondrial clusters. A complex type of germ plasm generation, ‘the follicle cell assigned germ plasm formation’, was found in late oogenesis. The mechanisms discovered are recommended to be taken into account for possible reconstruction of those under in vitro conditions.

SummaryThis report presents data from ultrastructural and morphometric studies on the germinal-body-like structures, nuage, nuage–mitochondrial clusters and chromatoid bodies in 4.5-day embryo cells and spermatogenic cells of the laboratory mouse Mus musculus. In the 4.5-day embryo cells the germinal-body-like structures that, according to previous data, arise by condensation of mitochondria in Graafian oocytes, were found not to undergo any ultrastructural alterations. In spermatogonia the germinal-body-like structures presumably were transformed into nuage that functioned as ‘intermitochondrial cement’ binding the mitochondrial clusters. In primary spermatocytes mitochondria aggregated by nuage were found with large vacuoles containing membraneous conglomerates that were obviously excreted by organelles into the cytoplasm. The chromatoid bodies that arose in spermatocytes and finally disintegrated in the posterior part of late spermatids seemed not to be implicated in the pathway of the germinal-body-like structure. The dispersion of chromatoid bodies was noted to be accompanied by excretion of membraneous conglomerates by late spermatid mitochondria. The spermatozoa were not found to contain either the germinal-body-like structures or any other germ-plasm-related structures.

Multiple specific granular structures are present in the cytoplasm of germ cells, termed nuage, which are electron-dense, non-membranous, close to mitochondria and/or nuclei, variant size yielding to different compartments harboring different components, including intermitochondrial cement (IMC), piP-body, and chromatoid body (CB). Since mitochondria exhibit different morphology and topographical arrangements to accommodate specific needs during spermatogenesis, the distribution of mitochondria-associated nuage is also dynamic. The most relevant nuage structure with mitochondria is IMC, also called pi-body, present in prospermatogonia, spermatogonia, and spermatocytes. IMC is primarily enriched with various Piwi-interacting RNA (piRNA) proteins and mainly functions as piRNA biogenesis, transposon silencing, mRNA translation, and mitochondria fusion. Importantly, our previous work reported that mitochondria-associated ER membranes (MAMs) are abundant in spermatogenic cells and contain many crucial proteins associated with the piRNA pathway. Provocatively, IMC functionally communicates with other nuage structures, such as piP-body, to perform its complex functions in spermatogenesis. Although little is known about the formation of both IMC and MAMs, its distinctive characters have attracted considerable attention. Here, we review the insights gained from studying the structural components of mitochondria-associated germinal structures, including IMC, CB, and MAMs, which are pivotal structures to ensure genome integrity and male fertility. We discuss the roles of the structural components in spermatogenesis and piRNA biogenesis, which provide new insights into mitochondria-associated germinal structures in germ cell development and male reproduction.

The induced pluripotent stem cells (iPSCs) have an intrinsic capability for indefinite self-renewal and large-scale expansion and can differentiate into all types of cells. Here, we tested the potential of iPSCs from dental pulp stem cells (DPSCs) to differentiate into functional odontoblasts. DPSCs were reprogrammed into iPSCs via electroporation of reprogramming factors OCT-4, SOX2, KLF4, LIN28, and L-MYC. The iPSCs presented overexpression of the reprogramming genes and high protein expressions of alkaline phosphatase, OCT4, and TRA-1-60 in vitro and generated tissues from 3 germ layers in vivo. Dentin discs with poly-L-lactic acid scaffolds containing iPSCs were implanted subcutaneously into immunodeficient mice. After 28 d from implantation, the iPSCs generated a pulp-like tissue with the presence of tubular dentin in vivo. The differentiation potential after long-term expansion was assessed in vitro. iPSCs and DPSCs of passages 4 and 14 were treated with either odontogenic medium or extract of bioactive cement for 28 d. Regardless of the passage tested, iPSCs expressed putative markers of odontoblastic differentiation and kept the same mineralization potential, while DPSC P14 failed to do the same. Analysis of these data collectively demonstrates that human iPSCs can be a source to derive human odontoblasts for dental pulp research and test bioactivity of materials.

Objetivo: Comunicar la eficacia del clavo endomedular recubierto con antibiótico (CERA) para erradicar la infección en la seudoartrosis infectada de húmero (SIH).Materiales y Métodos: Once pacientes (edad promedio 48 años). El tiempo entre la fractura y la cirugía fue 25 meses. El CERA se impregnó con vancomicina en 9 pacientes. El seguimiento promedio fue de 54 meses.Resultados: Se aisló S. aureus resistente a meticilina (SARM) en 5 pacientes. Todos recibieron antibióticos sistémicos por 7 semanas. El antibiótico más utilizado fue vancomicina. La mediana entre el primer tiempo quirúrgico y la reconstrucción fue 56 días (RIC 47-98). Luego del desbridamiento quirúrgico del primer tiempo, se midió el defecto óseo remanente y se lo dividió con variables dicotómicas: grupo con defectos <2 cm (7 pacientes) y grupo con defectos ≥2 cm (4 pacientes). No se observaron diferencias significativas entre la mediana de días entre el primero y segundo tiempo quirúrgico comparando el desarrollo de SARM con el de otros gérmenes (48 días [RIC 45-75] vs. 73,5 días [RIC 56-149], p = 0,2002 Mann-Whitney), ni en la proporción del tamaño del defecto óseo según el desarrollo de SARM o de otro germen (60% vs. 17%, p = 0,242 Fisher). Todos los cultivos fueron negativos y se logró la consolidación del foco fracturario, sin recurrencia de la infección.Conclusiones: El CERA es una buena opción terapéutica en el primer tiempo quirúrgico para un paciente con SIH. Se pudo controlar la infección, lo que permitió la reconstrucción secundaria de la seudoartrosis. AbstractObjetive: To evaluate the efficiency of the antibiotic cement rod (ACR) in the eradication of infection in infected humerusnonunion (IHN).Material and methods: We included 11 patients with IHN with a mean age of 48 years. The time between fracture-surgery was 25 months. The ACR was impregnated with vancomycin in 9 of de 11 cases. Follow-up was 54 months.Results: Methicillinresistant staphylococcus aureus (MRSA) was isolated in 5 of cases. All patients received antibiotics systemically for 7 weeks. Vancomycin was the most commonly used antibiotic. Time between ACR and reconstructive surgery averaged 56 days [confidence interval range (CIR) 47-98]. After debridement and implant removal, the residual space of the nonunion was measured with dichotomous variables and classified into two groups: group 1, < 2 cm (7 patients) and group 2, ≥2 cm (4 patients). No significant differences were observed between the number of days in which the ACR was placed and the development of the SAMR as compared to other germs [48 days (CIR 45-75) vs. 73 days (CIR 56-149) p= 0.2002 Mann Whitney]. Nor were differences observed in the size of the defect in those who developed MRS or any other germ (p=0.242 Fisher). Reconstruction was performed with different techniques. Laboratory parameters were normal, cultures were negative. Fractures could be consolidated without infection recurrence.Conclusions: ACR is a good treatment option for a patient with an INH. The infection could be controlled in all of the cases, which allowed the secondary reconstruction of the nonunion

Abstract. Periprosthetic joint infection (PJI) is one of the most challenging complications after joint replacement. However, when treated correctly, chances of recovery are good. The most important step in correct diagnosis and management of PJI is the detection of the causative germ. In the last years, the use of sonication in the diagnostic process has become more important. However, this diagnostic methodology has been controversially discussed when used in combination with antibiotic loaded bone cement (PMMA), which is frequently used in joint replacement surgeries. The aim of this study was thus to analyse in vitro bacterial growth in sonication fluid cultures obtained from antibiotic loaded PMMA which were contaminated with various bacterial biofilms.Sonication fluid obtained from antibiotic loaded PMMA (Copal G+V and Copal G+C) and plain Palacos R (control) contaminated either with S. aureus, E. faecalis, S. sanguinis or P.acnes, were analysed for bacterial re-growth in a standardised in-vitro setting.In vitro bacterial growth was not interfered by released antibiotics from sonication of antibiotic loaded PMMA for S. aureus, E. faecalis and S. sanguinis. However, for P. acnes bacterial counts were affected by the released antibiotics as well as by the time delay between sonication and analysis. The in-vitro data suggest sonication to be an easy and sensitive diagnostic modality to detect easy-to-detect bacteria, however, results are alarming for the difficult-to-detect bacteria P. acnes, indicating that further attention and research is necessary to improve the detection of difficult-to-detect bacteria.

Preferentially expressed antigen in melanoma (PRAME) is a cancer/testis antigen that is predominantly expressed in normal testicular tissues and a variety of tumors. The function of the PRAME family in spermatogenesis remains unknown. This study was designed to characterize the Y-linked PRAME (PRAMEY) protein during spermatogenesis in cattle. We found that PRAMEY is a novel male germ cell-specific, and a germinal granule-associated protein that is expressed in spermatogenic cells during spermatogenesis. The intact PRAMEY protein (58 kDa) was detected in different ages of testes but not in epididymal spermatozoa. A PRAMEY isoform (30 kDa) was highly expressed only in testes after puberty and in epididymal spermatozoa. This isoform interacts with PP1γ2 and is likely the mature protein present in the testes and sperm. Immunofluorescent staining demonstrated that PRAMEY was located predominantly in the acrosome granule of spermatids, and in acrosome and flagellum of spermatozoa. Immunogold electron microscopy further localized the PRAMEY protein complex to the nucleus and several cytoplasmic organelles, including the rough endoplasmic reticulum, some small vesicles, the intermitochondrial cement, the chromatoid body and the centrioles, in spermatogonia, spermatocytes, spermatids and/or spermatozoa. PRAMEY was highly enriched in and structurally associated with the matrix of the acrosomal granule (AG) in round spermatids, and migrated with the expansion of the AG during acrosomal biogenesis. While the function of PRAMEY remains unclear during spermatogenesis, our results suggest that PRAMEY may play an essential role in acrosome biogenesis and spermatogenesis.Free Chinese abstract: A Chinese translation of this abstract is freely available athttp://www.reproduction-online.org/content/153/6/847/suppl/DC2Spanish abstract: A Spanish translation of this abstract is freely available athttp://www.reproduction-online.org/content/153/6/847/suppl/DC3