Thiol oxidation by nitrosative stress: Cellular localization in human spermatozoa

Peroxynitrite is a highly reactive nitrogen species and when it is generated at high levels it causes nitrosative stress, an important cause of impaired sperm function. High levels of peroxynitrite have been shown to correlate with decreased semen quality in infertile men. Thiol groups in sperm are mainly found in enzymes, antioxidant molecules, and structural proteins in the axoneme. Peroxynitrite primarily reacts with thiol groups of cysteine-containing proteins. Although it is well known that peroxynitrite oxidizes sulfhydryl groups in sperm, the subcellular localization of this oxidation remains unknown. The main objective of this study was to establish the subcellular localization of peroxynitrite-induced nitrosative stress in thiol groups and its relation to sperm motility in human spermatozoa. For this purpose, spermatozoa from healthy donors were exposed in vitro to 3-morpholinosydnonimine (SIN-1), a compound which generates peroxynitrite. In order to detect peroxynitrite and reduced thiol groups, the fluorescent probes, dihydrorhodamine 123 and monobromobimane (mBBr), were used respectively. Sperm viability was analyzed by propidium iodide staining. Peroxynitrite generation and thiol redox state were monitored by confocal microscopy whereas sperm viability was evaluated by flow cytometry. Sperm motility was analyzed by CASA using the ISAS^® system. The results showed that exposure of human spermatozoa to peroxynitrite results in increased thiol oxidation which is mainly localized in the sperm head and principal piece regions. Thiol oxidation was associated with motility loss. The high susceptibility of thiol groups to peroxynitrite-induced oxidation could explain, at least in part, the negative effect of reactive nitrogen species on sperm motility.

Abbreviations: DHR: dihydrorhodamine 123; mBBr: monobromobimane ONOO^?: peroxynitrite RNS: reactive nitrogen species RFI: relative fluorescence intensity SIN-1: 3-morpholinosydnonimine CASA: Computer-Aided Sperm Analysis PARP: poli ADP ribose polimerasa VCL: curvilinear velocity VSL: straight-line velocity VAP: average path velocity PRDXs: peroxiredoxins ODF: outer dense fiber ODF1: outer dense fiber 1 PI: propidium iodide DMSO: dimethyl sulfoxide SD: standard deviation ANOVA: analysis of variance     

Obturation of accessory canals after four different final irrigation regimes

The aim of this study was to evaluate accessory canal obturation after four different final irrigation regimes. Sixty-four extracted human lower premolars were instrumented, divided randomly into four groups, and finally irrigated as follows: no irrigation (NO), distilled water (WA), sodium hypochlorite ([SH] 6%, 20 ml for 15 min), and EDTA (15%, 8 ml for 3 min) combined with the SH regimen (ES). The System B and the Obtura II were used to fill the canals. The teeth were cleared and observed under a digital microscope. Obturation material penetration rates in length into the accessory canals were measured and the following values were obtained: 22.3% in group NO, 21.8% in group WA, 53.5% and 68.1% in groups SH and ES, respectively. Statistically significant differences were found when comparing each of the first two groups (NO and WA) with SH and ES groups (p < 0.05). The use of sodium hypochlorite alone or in combination with EDTA in final irrigation flushes may enhance a better obturation material penetration into the accessory canals.     

Intracanal temperature rise evaluation during the usage of the System B: replication of intracanal anatomy

AIM: To evaluate and determine intracanal temperature rises at 2 and 4 mm from the working length (WL) necessary to obtain proper replication of intracanal anatomy with gutta-percha (GP) using the System B heat source during vertical condensation. METHODOLOGY: A split-tooth model was prepared and artificial shallow depressions were cut in the buccal canal wall 2 and 4 mm from the WL. At the same level on the palatal wall holes were drilled to adapt two thermocouples. The canal was filled using GP in a vertical condensation technique by placing the System B plugger at 2 and 4 mm from the WL in groups A and B, respectively. Two control groups in which no GP was used were carried out placing the plugger 2 and 4 mm from the WL (groups A.c and B.c, respectively) and activating the heat source. Recording of temperature rise was carried out during the filling procedure for groups A and B and during activation for control groups A.c and B.c; the highest temperatures were recorded. After each filling was completed, 3 min were allowed for the GP to cool and the model divided to reveal the filling. Images of the GP were taken with a CCD camera to evaluate the presence of replication of artificial round depressions. In control groups, the temperature was recorded for 20 s after a 3 s activation of the heat source. The rise in temperature was compared between the groups individually at each level (2 or 4 mm) and statistically analysed using one-way anova and Fisher PLSD tests at 5% of significance level (P < 0.05). RESULTS: Mean temperature rises of 14 +/- 3 and 12 +/- 2 degrees C at 2 and 4 mm from the WL, respectively, were observed in group A fillings, and 4 +/- 1 and 6 +/- 1 degrees C at 2 and 4 mm, respectively, in group B fillings. Recordings at 2 mm showed significantly (P < 0.05) higher temperature rises with group A.c when compared with groups B and B.c. Replication of intracanal anatomy with GP was always found in group A fillings at both levels but only 4 mm from the WL in group B fillings. CONCLUSIONS: Positioning the plugger close to WL and a temperature rise of 6 degrees C were necessary to obtain replication of intracanal anatomy. A mean temperature rise of 4 degrees C at 2 mm from WL (group B) resulted in no replication of intracanal anatomy. Further studies simulating clinical conditions are necessary.     

A case of slipped capital femoral epiphysis results from hypophosphatemic rickets： treatment and midterm follow-up

In this case, a male patient presented with a clinically and radiographieally unstable slipped capital femoral epiphysis （SCFE） as well as slipped calcaneal epiphysis years. Subsequent thorough at the age of 23 work-up revealed that he had some features of rickets and labo- ratory test demonstrated he had hypophos- phatemia （2.3mg/dl）, normocalcemia, normal vi- tamin D metabolite levels, and secondary hy- perparathyroidism.     

Liver Transplantation in Recipients With High Model for End-stage Liver Disease Score

Objectives

The score in the Model of End-stage Liver Disease, or MELD, is a good indicator of the survival in patients on the liver transplant waiting list. In this study, an analysis is performed on the benefits of liver transplant on those patients with a very high MELD score and who thus start from a very severe baseline state that could affect the surgical outcome.

间充质干细胞的来源

目的:间充质干细胞具有强大的增殖能力和多向分化潜能,文章对其主要的来源途径予以综述。资料来源:应用计算机检索Medline1991-01/2006-01期间的相关文章,检索词为“mesenchyma stem cells,origin,research progress”,并限定文章语言种类为English。同时计算机检索中国期刊全文数据库1998-01/2006-10期间的相关文章,检索词为“间充质干细胞,来源,研究进展”,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:①间充质干细胞的起源。②间充质干细胞研究进展、干细胞的分离及鉴定。排除标准:重复研究、个案报告或Meta分析类文章。资料提炼:共收集到96篇相关文献,40篇文献符合纳入标准,排除的56篇文献为内容陈旧或重复。符合纳入标准的40篇文献中,分别涉及骨髓、肌肉、脐血、胎盘、外周血、脂肪组织、血管及其他来源的间充质干细胞。资料综合:间充质干细胞是属于中胚层的一类多能干细胞,具有强大的增殖能力和多向分化潜能,动物模型试验和临床应用研究也取得了一定的效果。间充质干细胞来源广泛,易于获得,临床上为神经损伤及其他系统的损伤修复提供了更为广泛的途径。结论:间充质干细胞主要来源于骨髓、肌肉、脐血、外周血、胎盘等组织,具有广阔的应用前景。