125 research outputs found
The role of the family in attributing meaning to living with HIV and its stigma in Turkey
Stigma attached to HIV/AIDS remains a global problem, with severe negative consequences for people living with HIV (PLHIV). Family support is fundamental for PLHIV’s psychological and physical well-being. HIV-related stigma is high in Turkey, where HIV/AIDS prevalence is low and the epidemic is not considered a priority. Based on qualitative data generated with HIV-positive women and men, this article explores the process of stigmatization, as experienced and perceived by PLHIV in Turkey, focusing on the institution of the family. Results indicated that enacted stigma from family members is lower than anticipated. While most participants’ narratives showed patterns of support rather than rejection from families, the strong expectations around the cultural value attributed to “the family” are found to be the main facilitators of internalized stigma. The article critically discusses the meaning and implications of family support, addressing the role of patriarchal values attributed to womanhood, manhood, and sexuality in Turkey
Understanding atmospheric organic aerosols via factor analysis of aerosol mass spectrometry: a review
Organic species are an important but poorly characterized constituent of airborne particulate matter. A quantitative understanding of the organic fraction of particles (organic aerosol, OA) is necessary to reduce some of the largest uncertainties that confound the assessment of the radiative forcing of climate and air quality management policies. In recent years, aerosol mass spectrometry has been increasingly relied upon for highly time-resolved characterization of OA chemistry and for elucidation of aerosol sources and lifecycle processes. Aerodyne aerosol mass spectrometers (AMS) are particularly widely used, because of their ability to quantitatively characterize the size-resolved composition of submicron particles (PM1). AMS report the bulk composition and temporal variations of OA in the form of ensemble mass spectra (MS) acquired over short time intervals. Because each MS represents the linear superposition of the spectra of individual components weighed by their concentrations, multivariate factor analysis of the MS matrix has proved effective at retrieving OA factors that offer a quantitative and simplified description of the thousands of individual organic species. The sum of the factors accounts for nearly 100% of the OA mass and each individual factor typically corresponds to a large group of OA constituents with similar chemical composition and temporal behavior that are characteristic of different sources and/or atmospheric processes. The application of this technique in aerosol mass spectrometry has grown rapidly in the last six years. Here we review multivariate factor analysis techniques applied to AMS and other aerosol mass spectrometers, and summarize key findings from field observations. Results that provide valuable information about aerosol sources and, in particular, secondary OA evolution on regional and global scales are highlighted. Advanced methods, for example a-priori constraints on factor mass spectra and the application of factor analysis to combined aerosol and gas phase data are discussed. Integrated analysis of worldwide OA factors is used to present a holistic regional and global description of OA. Finally, different ways in which OA factors can constrain global and regional models are discussed
An improved method for inference of piecewise linear systems by detecting jumps using derivative estimation
Inference of dynamical systems using piecewise linear models is a promising active research area. Most of the investigations in this field have been stimulated by the research in functional genomics. In this article we study the inference problem in piecewise linear systems. We propose first identifying the state transitions by detecting the jumps of the derivative estimates, then finding the guard conditions of the state transitions (thresholds) from the values of the state variables at the state transition time and finally using the conventional gene regulatory network inference methods to infer the regulatory relations. This approach does not require a priori information or assumption on the guard conditions and provides robustness to environmental or measurement noise underlined by the used jump detection filter. We discuss the particular problems where the suggested method can improve the efficiency and demonstrate the results on a comparative basis
The impact of granulocyte colony-stimulating factor (G-CSF) on thin endometrium of an animal model with rats
Purpose: To evaluate whether G-CSF improves the endometrial thickness of thin endometrium by influencing proliferative, angiogenic and apoptotic factors, an experimental rat model was conducted using 24 female adult rats with either thin or healthy endometrium that each was further divided into G-CSF or saline injection groups with six rats. Materials and methods: After forming of the thin endometrium by uterine injection of 0.2 ml 96% ethyl alcohol to the rats, five days of subcutaneous injections of 40 μg/kg G-CSF or saline were given. Endometrial thickness, immunohistochemically expression of vascular endothelial growth factor receptor-2 (VEGF-R2), proliferative cell nuclear antigen (PCNA) and fibronectin apoptosis with TUNEL method were compared in specimens among four groups of post-model rats. Results: Endometrial thickness was significantly improved in thin but not in normal endometrium group with GCSF when compared to saline injection. Stromal and glandular epithelial expression of PCNA and pericapillary VEGF-R2 was significantly increased, and apoptosis was significantly decreased with G-CSF. Although fibronectin was also increased with G-CSF in the thin endometrium, the difference was non-significant. In further, G-CSF decreased apoptotic cells and increased expression of PCNA when compared to saline injection in normal endometrium. Conclusions: G-CSF improves endometrial thickness, proliferation, angiogenesis and DNA fragmentation in thin endometrium. © 2020 Informa UK Limited, trading as Taylor & Francis Group
Immunohistochemical profile of transforming growth factor-ß1 and basic fibroblast growth factor in sciatic nerve anastomosis following pinealectomy and exogenous melatonin administration in rats
PubMed ID: 16831553Collagen scar formation at the cut end of a peripheral nerve, an important problem in clinical practice for neurosurgeons, obstructs sprouting of axons into appropriate distal fascicles, and thereby limits the regeneration process. Researchers have attempted to control collagen accumulation and neuroma formation with various physical and chemical methods, but with limited functional success. Recently, it has been demonstrated that transforming growth factor (TGF)-ß and basic fibroblast growth factor (bFGF) play an important role in collagen production by fibroblasts and in Schwann cell activity. In our study, rats were divided into a control group, a melatonin-treated group, a surgical pinealectomy group, and a group treated with melatonin following pinealectomy. They then underwent a surgical sciatic nerve transection and primary suture anastomosis. At 2 months after anastomosis, the animals were sacrificed and unilateral sciatic nerve specimens, including the anastomotic region, were removed and processed for immunohistochemical study from two animals in each group. For each antibody, immunoreactivity was assessed using a semiquantitative scoring system. Strong TGF-ß1 and/or bFGF expression was observed in the epineurium of animals that underwent pinealectomy, but no or weak staining was observed in animals in the control and melatonin treatment groups. Based on these data, we suggest that both TGF-ß1 and bFGF have important roles in control of collagen accumulation and neuroma formation at the anastomotic site, and that the pineal neurohormone melatonin has a beneficial effect on nerve regeneration. © 2006 Elsevier Ltd. All rights reserved.The authors are grateful to Professor S. Kaplan for helpful discussions and M. Koltas for linguistic help. We also extend our thanks to Mr. B. Ata, Mr. Ç. Uz, and Mrs. S. Balkız for their skilful technical assistance. This work was supported by a grant from the Scientific and Technical Research Council of Turkey (TUBITAK), Grant No. SBAG-2323 (100S075). This study was presented in part at the 4 th Asian-Pacific International Congress of Anatomists (APICA), 7–10 September 2005, Kusadasi, Turkey. -
Assessment of effects of pinealectomy and exogenous melatonin administration on rat sciatic nerve suture repair: An electrophysiological, electron microscopic, and immunohistochemical study
PubMed ID: 15565477Background. Collagen scar formation at the cut end of a nerve, an important problem in clinical practice for neurosurgeons in peripheral nerve surgery, obstructs sprouting of axons into appropriate distal fascicles, and thereby limits nerve regeneration. Researchers attempt to control collagen accumulation in the formation of neuroma by various physical and chemical methods, but these have yielded only limited functional success. This is the first experimental study investigating the effects of melatonin (MLT) on nerve repair and neuronal regeneration in rat sciatic nerve suture repair. Methods. The hypothesis that exogenous MLT administration may inhibit the formation of neuroma in peripheral nerve surgery was investigated in rat sciatic nerve model. In this study, a total of 80 rats were used for control groups (Groups Ia, Ib, IIa, and IId), MLT group (Group Ic), surgical pinealectomy (Px) groups (Groups IIb and IIc), and group of MLT treatment following Px procedure (Group IIe). All animals underwent a surgical intervention consisting of bilateral sciatic nerve section and primary suture repair. At 8 weeks after repair, the animals were killed following completion of recording of nerve action potentials (NAPs). Then, unilateral sciatic nerve specimens including the suture repair region were carefully removed and the excised segments were processed for electron microscopy examination. Afterwards, contralateral sciatic nerve specimens from two animals from each group were removed and stained for immunohistochemical analysis. Results. Results of morphometric analysis revealed that Px procedure caused an elevation of collagen content of the sciatic nerve and macroscopic neuroma formation, and that there was a statistically significant reduction in collagen content of the same region in pinealectomized animals treated with MLT (p < 0.001). Accordingly, electrophysiological findings demonstrated that the stimulus intensities required to excite a NAP response were increased in surgical Px group, but the presence of a reduced threshold response was found in the group treated with MLT following Px procedure (p < 0.01). Immunohistochemical staining for Type I collagen and Type III collagen was markedly more intense in the epineurium of animals after Px. Virtually no or only weak staining was observed in animals in control groups and the MLT treatment group. Results of immunohistochemical analysis revealed that surgical Px procedure caused a strong immunoreactivity for Type I collagen and Type III collagen in all connective tissue planes of the nerve, especially in the epineurium, and there was a statistically significant reduction in immunoreactivity of the repair region in animals receiving MLT treatment after Px procedure (p < 0.001). Conclusion. This study demonstrates that exogenous MLT administration significantly inhibits collagen accumulation in the formation of neuroma in the suture repair site and thereby improves nerve regeneration. From a clinical standpoint, the positive effect of MLT administration on neuroma formation and nerve regeneration seems a particularly attractive treatment option. Therefore, we believe that nerve repair with addition of MLT may be a worthwhile option in addition to other treatment modalities in case of MLT deficiency, such as aging. However, further experimental and clinical studies using functional analysis warranted to confirm this result in future. © Springer-Verlag 2004
Evaluation and comparison of in vitro biocompatibility of Poly (glycolic acid) and poly (lactide-co-glycolide acid) on mature spheroids of tumorigenic and non-tumorigenic cell lines [Poliglikolik asit ve polilaktid ko-glikolid asitlerinin tümörijenik ve non-tümörijenik matür sferoidlerde i·n vitro biyouyumlulugunun degerlendirilmesi ve karşilaştmlmasi]
Objective: The aim of this study was to evaluate and compare in vitro biocompatibility and poly(glycolic acid) (PGA) and poly(lactide-co-glycolide acid) (PLGA) on tumorigenic and non-tumorige- nic mature spheroids. Material and Methods: This is an in vitro experimental study. Tumorigenic (C6 glioma, SH-SY5Y, MDAH2774, MCF-7) and non-tumorigenic cells [CRL11372, primary osteoblasts (MCPO)] as well as their mature spheroids were cultured alone as a control group as well as in combination with PGA and PLGA. Total cell numbers, bromodeoxyuridine labeling index (BrDU-LI), apoptosis, morphology, and ultrastructure were evaluated. Results: PGA and PLGA significantly decreased the number of SH- SY5Y and C6 glioma cells; MDAH 2774 cells also decreased, but not significantly (p> 0.05). Low BrDU- LI (p< 0.05) with a high level of apoptosis (p< 0.05) at C6 glioma and a high level of BrDU-LI (p< 0.05) with a low level of apoptosis at MDAH2774 (p< 0.01) were noted. These biopolymers mostly decreased the number of CRL-11372 cells (p< 0.05), but indicated an increased apoptosis (p< 0.01) and significant BrDU- LI (p< 0.05). Biopolymers induced chromatin condensation (typical apoptotic ultrastructure) and vacuolization primarily at SH-SY5Y spheroids but rarely at MDAH-2774 spheroids. This apoptotic ultrastucture was most often observed at MCPO spheroids. PLGA and PGA induced similar BrDU-LI decreases among tumorigenic spheroids (p< 0.05), although this decrease was greater at MCF-7 (p< 0.05) in the PGA group. PGA primarily decreased BrDU-LI at CRL 11372 (p< 0.05), although the decrease was almost identical to that at MCPO for the two biopolymers (p< 0.05). A significant attachment affinity was determined at MDAH -2774 and C6 glioma spheroids. Conclusion: This study demonstrated the biocompatibility of PGA and PLGA at mature spheroids of tumorigenic and non-tumorigenic cell lines, which changed according to the cell type. © 2011 by Türkiye Klinikleri
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