Abnormal assembly of annulate lamellae and nuclear pore complexes coincides with fertilization arrest at the pronuclear stage of human zygotic development

BACKGROUND: The assembly of nuclear pore complexes (NPC) and their cytoplasmic stacks, annulate lamellae (AL), promote normal nucleocytoplasmic trafficking and accompany pronuclear development within the mammalian zygote. Previous studies showed that a percentage of human oocytes fertilized in vitro failed to develop normal pronuclei and cleave within 40-48 h post insemination. We hypothesized that an aberrant recruitment of NPC proteins, nucleoporins and/or NPC preassembled into AL, might accompany human fertilization arrest. METHODS AND RESULTS: We explored NPC and AL assembly in unfertilized human oocytes, and fertilized and arrested zygotes by immunofluorescence with an NPC- and AL-specific antibody, mAb 414, and by transmission electron microscopy. Major NPC or AL assembly was not observed in the unfertilized human oocytes. Once fertilization took place, the formation of AL was observed throughout the cytoplasm and near the developing pronuclei with NPC. On the contrary, NPC assembly was disrupted in the arrested zygotes, whereas AL were clustered into large sheaths. This was accompanied by the lack of NPC incorporation into the nuclear envelopes. CONCLUSIONS: We conclude that the aberrant assembly of NPC and AL coincides with early developmental failure in humans.     

Cytoskeletal organization defects and abortive activation in human oocytes after IVF and ICSI failure

In this study, we analysed the distribution of beta tubulins to detect spindle and cytoplasmic microtubules, alpha acetylated tubulins for sperm microtubules and chromatin configuration in oocytes showing fertilization failure after conventional IVF or intracytoplasmic sperm injection (ICSI). A total of 450 human oocytes that failed to fertilize were studied 20-40 h after IVF or ICSI. In all, 287 oocytes were stained for immunofluorescence and chromosomal spreads were performed by Tarkowski's air-drying method in 163 IVF or ICSI oocytes that did not develop pronuclei after the extrusion of a second polar body. Immunofluorescence analysis showed that the main reason of fertilization failure after IVF was no sperm penetration (55.5%). The remaining oocytes showed different abnormal patterns, e.g. oocyte activation failure (15.1%) and defects in pronuclei apposition (19.2%). On the other hand, fertilization failure after ICSI was mainly associated to incomplete oocyte activation (39.9%), and to a lesser extent with defects in pronuclei apposition (22.6%) and failure of sperm penetration (13.3%). A further 13.3% of the ICSI oocytes arrested their development at the metaphase of the first mitotic division. The chromosomal spreads allowed the analysis of abortive activations, in which no pronuclei formed but a second polar body was extruded. Immunofluorescence and cytogenetic analysis provided a useful tool to improve infertility diagnosis and prognosis in each particular case.     

Clinical and microbiological characteristics of unusual manifestations of invasive pneumococcal disease

Introduction

Invasive pneumococcal disease (IPD) typically presents as bacterial pneumonia, meningitis or primary bacteraemia. However, Streptococcus pneumoniae can produce infection at any level of the body (endocarditis, arthritis, spontaneous bacterial peritonitis, etc.), which is also known as unusual IPD (uIPD). There are very limited data available about the clinical and microbiological profile of these uncommon manifestations of pneumococcal disease. Our aim was to analyse clinical forms, microbiological profile, epidemiology and prognosis of a cohort of patients with unusual invasive pneumococcal disease (uIPD).

Long-term histologic study of a new carbon-carbon ossicular replacement prosthesis

In a variety of structural forms, carbon possesses certain properties that render it suitable for implantation in the human body. This report analyzes biocompatibility of a new carbon-carbon prosthesis following long-term middle ear implantation in a prospective, controlled animal study. The prosthesis was placed in the left ear of 20 healthy guinea pigs and in the dorsal subcutaneous tissues for control. The right ear also served as control. Preoperative and postoperative auditory evoked potentials were recorded and compared. Samples of tissue from all three sites were evaluated at 3 and 6 months by light microscopy. The implants also were evaluated by scanning electron microscopy. Samples of lymph nodes, liver, spleen, and lungs also were examined. Fourteen animals (70%) demonstrated no change in auditory evoked potentials postoperatively. One animal developed unilateral dysfunction and three others developed bilateral dysfunction for unexplained reasons. No significant tissue destruction or inflammation of the tissues and no digestion or erosion of the implants were observed. No passage of carbon particles into the reticuloendothelial system was identified. These preliminary results suggest that this new carbon-carbon prosthesis may be biocompatible at 6 months follow-up in the guinea pig and encourage further investigation.     

Transabdominal versus endovaginal pelvic sonography: prospective study

Transabdominal and endovaginal pelvic sonograms were obtained in 108 nonpregnant patients referred for pelvic sonography. The studies were independently obtained by two radiologists and interpreted on the basis of identical clinical information. The sonograms were then compared for anatomic detail and abnormalities. A determination was made about which examination, if either, was superior. Follow-up was performed through a review of the medical records and follow-up studies. Overall, the endovaginal study was judged superior in 65 cases (60.2%), equal in 39 (36.1%), and inferior in four (3.7%). The authors conclude that the endovaginal examination can effectively replace the transabdominal examination as the initial approach for routine pelvic sonography.     

马来酰亚胺苯甲氨酯聚乙二醇修饰膜蛋白掩盖AB和RhD抗原制备通用血型红细胞

聚乙二醇(PEG)上的活性基团结合在红细胞表面掩盖血型抗原是制备通用血型红细胞的途径之一,这些PEG链有很强的水合作用,能覆盖红细胞表面的大片区域,阻断血型抗原与抗体结合。甲基氧PEG-5000(mPEG-5000)是常用的红细胞修饰剂,主要修饰蛋白上的氨基基团。在氯化氰脲酸(CnCl)催化下,mPEG-5000与红细胞膜上氨基形成共价键连接,掩盖Rh抗原和A或B抗原。CnCl-PEG-5000浓度越高,血型抗原的覆盖效果越好。由于微环境下A和B血型抗原处无氨基基团或者氨基基团不能被CnCl-PEG-5000修饰,不能完全阻断抗-A、B与A和B血型抗原结合。本文报道…