141 research outputs found
Do sperm and lubricants gel well with each other?:A systematic review
Vaginal lubricants are commonly used to aid sexual pleasure and/or to help combat vaginal dryness and dyspareunia. Several studies have reported their impact on sperm function, however there are no published guidelines to help healthcare professionals and couples select a vaginal lubricant that is 'sperm-safe'. To address this, we conducted a literature search using both PubMed and Scopus to identify and appraise manuscripts that reported the impact of lubricants on sperm function. We did not restrict the literature search by year of publication, and we only included manuscripts that looked at the impact of vaginal lubricants on human sperm. The quality of the eligible studies was assessed using the Björndahl et al., (2016) checklist for semen analysis, as most of the studies reported the findings of a basic semen analysis. A total of 24 articles were eligible for analysis with a total of 35 vaginal lubricants (that were available to buy over the counter) being included, 2 of which studied the effect of vaginal lubricants on sperm function in vivo, and 22 being conducted in vitro. KY Jelly, PreSeed and Astroglide were most studied, with most manuscripts focussing on their impact on sperm motility. A paucity of data on most lubricants combined with methodological variations between studies and limited/no reporting on pregnancy outcomes means greater efforts are required before an evidence-based guideline can be published.</p
Do sperm and lubricants gel well with each other?:A systematic review
Vaginal lubricants are commonly used to aid sexual pleasure and/or to help combat vaginal dryness and dyspareunia. Several studies have reported their impact on sperm function, however there are no published guidelines to help healthcare professionals and couples select a vaginal lubricant that is 'sperm-safe'. To address this, we conducted a literature search using both PubMed and Scopus to identify and appraise manuscripts that reported the impact of lubricants on sperm function. We did not restrict the literature search by year of publication, and we only included manuscripts that looked at the impact of vaginal lubricants on human sperm. The quality of the eligible studies was assessed using the Björndahl et al., (2016) checklist for semen analysis, as most of the studies reported the findings of a basic semen analysis. A total of 24 articles were eligible for analysis with a total of 35 vaginal lubricants (that were available to buy over the counter) being included, 2 of which studied the effect of vaginal lubricants on sperm function in vivo, and 22 being conducted in vitro. KY Jelly, PreSeed and Astroglide were most studied, with most manuscripts focussing on their impact on sperm motility. A paucity of data on most lubricants combined with methodological variations between studies and limited/no reporting on pregnancy outcomes means greater efforts are required before an evidence-based guideline can be published.</p
Hepatic stellate cells - Regional stem cells of the liver or a component of microenvironment?
For years, it is debated about the nature and localization of stem cell of the liver. In recent years, a particular interest is paid to hepatic stellate cells. According to the conducted researches, these cells are actively involved in restoring of hepatocytes population by different liver damages and they have a number of properties specific to stem cells. It should be noted that hepatic stellate cells are able to maintain viability in culture and differentiate into hepatocyte direction under certain conditions in vitro. Interestingly, hepatic stellate cells may themselves create such conditions for progenitor cells in vivo, as well as in vitro. This is achieved thanks to the hepatic stellate cells secretion of the extracellular matrix proteins, a complex of growth factors and establishment of direct intercellular contacts. Stellate cells, localized in perisinusoidal space, are also influenced by the surrounding hepatocytes and endothelial cells. Thus, perisinusoidal space is a kind of dynamic system, in which hepatocytes and endothelial cells determine the "resting" state of stellate cells, and the latter, if necessary, can be activated and participate in restoration of the liver cell populations. Based on these data, the researchers suggest that the hepatic perisinusoidal space - a niche of hepatic stellate cells, regional stem cells of the liver
Influence of the human umbilical cord blood mononuclear cells transplantation on regeneration of the rat kidney after unilateral ureteral obstruction
Stem cell therapy may provide effective and patogenetically proved treatment of chronic kidney disease caused by interstitial fibrosis after tubule damage. It was reported that transplanted bone marrow stem cells participate in tubule regeneration [1]. At the same time the potential of hematopoietic stem cells in tubule regeneration is not well investigated. The purpose of the study was to evaluate the participation of human cord blood stem cells in rat kidney tubule regeneration after unilateral ureteral obstruction. 18 laboratory rats were subjected to left unilateral ureteral obstruction (UUO). 3×106 of human cord blood mononuclears (n = 9) or equivalent volume of saline (n = 9) were injected into rat's tail vein. Kidney tissue was collected at the end of the 3, 6 or 14 day after operation. Paraffin-embedded slices were stained with mononuclear antibodies against c-kit (stem and progenitor cell marker), proliferating cell nuclear antigen for the cells proliferative capacity evaluation (PCNA) and α-smooth muscle actin (α-SMA) for myofibroblasts detection. Number of proliferating cells in tubuli ad interstitium was considerably larger in the obstructed kidney of the transplantation group, as well as the number of proliferating cells in the glomeruli at 14 day after operation. At the same time number of α-SMA-positive cells in the transplanted group was significantly lower compared with sham-transplanted group. There were no differences in expression of these markers in the contralateral kidneys. UUO had no impact on c-kit expression in kidney tissue. Thus, transplantation of human cord blood mononuclear cells in UUO stimulates proliferative activity of tubular cells and interstitium, reduces myofibroblast activation and risk of kidney fibrosis. © Human stem cells institute, 2013
Bread wheat callusogenesis and organogenesis using mature embryos as explants
Background. Bread wheat (Triticum aestivum L.) is one of the staple cereal crops, so it is of great interest to breeders and researchers and requires constant monitoring of existing cultivars, including the development of new ones through classical breeding and modern gene engineering. The key stage in these techniques is successful callusogenesis and organogenesis in target objects. With this in view, the regeneration potential of two spring (‘Saratovskaya 55’ and ‘Sigma’) and three winter (‘Tanya’, ‘Fisht’ and ‘Pamyat’) cultivars of bread wheat was assessed, and optimal conditions were identified for callus induction and organogenesis using mature embryos. Materials and methods. Immature and mature embryos of the five bread wheat cultivars were used in the study. The in vitro morphogenetic potential was evaluated under the impact of abiotic factors: preliminary exposure of grains to cold and use of exogenous hormones (2,4-D in various concentrations). Pretreatment of wheat with cold was carried out as follows: sterilized grains were incubated on the hormonal medium at a temperature of 4 °C for 2 weeks, and then transferred to 26 °C for 4 more weeks. The efficiency of callusogenesis and rhizogenesis was assessed and the numbers of morphogenetic calluses, regenerated and acclimatized plants were calculated. Results and conclusions. The analysis made it possible to identify the bread wheat cultivars ‘Fisht’ and ‘Sigma’ for their high morphogenetic and regenerative potential. It was also shown that exposure to cold can serve as a good stimulating factor for producing a large number of calluses, but regenerants are better induced under normal conditions. The results also depended on the concentration of hormones applied. Universal conditions for morphogenesis and regeneration were not identified
Arterial Stiffness Parameters and Subendocardial Viability Ratio in Patients with Arterial Hypertension Affected by Subclinical and Clinical Atherosclerosis
Aim. Assessment the arteries' stiffness parameters and subendocardial viability ratio in hypertensive patients with various degrees of severity of the atherosclerotic process manifestation.Material and methods. 133 hypertensive patients were divided into 3 groups, similar in age and sex, depending on the severity of the atherosclerotic process: hypertensive patients without atherosclerosis (n=42; 53.3±7.6 years); patients with hypertension and subclinical atherosclerosis (SА) (n=52; 56.5±8.0 years); patients with hypertension and coronary artery disease (CAD) (n=39; 57.4±6.8years) and control group which consisted of individuals without cardiovascular diseases (n=33; 54.6±8.4 years). All participants underwent 24-hour blood pressure monitoring with assessment of arterial stiffness parameters and subendocardial viability ratio (SERV).Results. Subjects from all groups with hypertension have significantly higher mean systolic blood pressure (SBP) (131.1±11.9, 127.8±14.8, 128.6±15.3 respectively; p<0.001), as well as central systolic blood pressure (SBPao) (122.0±11.0, 118.8±12.7, 119.9±13.3 respectively; p<0.001), pulse pressure (PP) (46.4±9.8, 45.6±10.6, 48.9±12.0 respectively; p<0.05) and central pulse pressure (PPao) (35.5±8.5, 34.9±8.5, 38.5±9.6 respectively; p<0.05), pulse wave velocity in aorta (PWVao) (11.3±1.5, 12.3±1.8, 11.5±1.7 respectively; p<0.05) compared with control group (SBP 116.3±7.3; SBPao 108.9±6.4, PP 39.9±6.5, PPao 30.9±5.4, PWVao 10.4±1.3). In hypertensive patients with SA, PWVao was significantly higher compared to other groups (p<0.05). With bringing the indicator to SBP 100 mmHg and HR=60 beats/min, there were no differences between the control group and the group with hypertension (p=0.3), also groups with hypertension+SA and hypertension+CAD did not significantly differ from each other (p=0.6). SERV in subjects with hypertension+SA was significantly lower than in patients with hypertension (p<0.05) and no significant differences were detected with the group with hypertension+CAD (p=0.77).Conclusions. In hypertensive patients with SA, a decrease in subendocardial perfusion is associated with an increase in pulse wave velocity in aorta. Moreover, such a decrease in perfusion approaches to the values of patients suffering from coronary artery disease, which indicates significant changes in the small vessels of the heart that form the coronary reserve
Can pancreas be the source of hepatocytes?
The possibility of hepatocytes differentiation from pancreatic cells is discussed in the review. Both liver and pancreas develop from endoderm so there could be a common stem cell giving rise to both pancreatic and liver cells. Different experimental models are used to study the possibility of hepatocytes development in pancreas such as influence of peroxisomes proliferation stimulators, hyperexpression of keratinocyte growth factor in pancreatic islets, Cu depletion-repletion model, etc.). There is no enough data to confirm which particular pancreatic cell type can be the source of hepatocytes. Literature data allow supposing that hepatocytes can arise in pancreas from three different sources: acinar, endocrine or ductular cells
Population Dynamics of MafA-Positive Cells During Ontogeny of Human Pancreas
© 2016, Springer Science+Business Media New York.Diverse transcription factors influencing cell differentiation are often chosen as markers of β cell progenitors. One of these transcription factors is MafA, which according to data in literature activates the expression of insulin gene in β cells. Other data support the hypothesis that MafA is required solely for the regulation of insulin secretion by β cells of adult islets and is not involved in the development of islet cells. In this paper, we study the role of MafA through both examination of human pancreas ontogeny and comparison of these data with dynamic changes in the population of insulin-positive and glucagon-positive cells. The aim of this research was the immunohistochemical analysis of MafA, insulin, and glucagon expression during human pancreas ontogeny. The research was conducted on whole embryos and isolated human fetal organs, obtained as a result of either miscarriage or legal medical abortion with voluntary consent of patients, and also on autopsy material from infant and adult human pancreas. As a result of this study, it was found that, during the ontogeny of human pancreas, the first MafA-positive cells appear in the islets at 12.5 weeks of gestation, that is, later than both insulin-positive cells (11.5 weeks of gestation) and glucagon-positive cells (8.5 weeks of gestation). No MafA-positive cells were found in the epithelium of pancreatic ducts. The number of MafA-positive cells in the islets increases during pancreatic organogenesis. The results of our research do not allow us to regard MafA as a marker of undifferentiated progenitors of islet cells. Based on this, we believe that the results obtained in this study are a supplementary contribution to the hypothesis that relates MafA to the markers of adult β cells
C-kit and desmin-positive cells in expression in islets of pancreas during alloxan diabetes in rats.
Nowadays there are findings that C-kit-positive and desmin-positive stellate cells help to regenerate endocrine part of pancreas. But still it is unknown about their role and the way of differentiation of these cells during pancreas regeneration. That's why the aim of our work was to study the dynamic of these cells population during alloxan diabetes in rats. The work was made on 33 rats with experimental diabetes. Blood glucose, insulin and glucagon levels were analyzed. Also the expression of desmin (marker of stellate cells), α-SMA (marker of myofibroblast), C-kit (marker of endocrine stem cells), insulin and glucagon (marker of differentiated α- And β-cells of Langerhans islets) was studied. The expression of desmin was found after one day of experimental diabetes in islets cells of pancreas. Maximum of these cells was after the third day of the experiment. Also after one day of the experiment C-kit-positive cells, which expressed insulin and glucagon were found. We suppose that stellate cells are the main factor of microenvironment for differentiation of C-kit-positive progenitor cells into β-cells through the stage of glucagon-positive cells because stellate pancreas cells can produce different growth factors and components of intercellular matrics. © Human stem cells institute, 2013
Participation of the mononuclear cells of the cord blood in the physiologic regeneration of the rat kidney
Nowadays ability to use hematopoietic stem cells for treatment of various diseases, including kidney pathology, is widely investigated. Umbilical cord blood as the source of hematopoietic stem cells becomes more and more promising. The purpose of our investigation was to study homing and ways of human umbilical cord blood mononuclear cells differentiation in an intact rat kidney. We transplanted human umbilical cord blood mononuclear cells fraction, enrich with hematopoietic stem cells, into the tail vein of rats. On 2, 5, 7 and 14 days after transplantation paraffin kidney slices were immunohistochemically stained with antibodies against human leukocyte antigen (HLA-ABC) to study migration and differentiation of transplanted cells. Results: HLA-ABC+- cells were revealed in the epithelium of the distal tubule at all experimental dates. But HLA-ABC was expressed not in each distal tubule and not by all tubular cells. We concluded that human umbilical cord blood mononuclear cells transplanted into systemic circulation of rat migrate into the intact kidney and built in the distal tubule epithelium. This data allow to suggest that distal tubule are stem cell «niche» in the kidney
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