Bovine cumulus-oocyte disconnection in vitro

Summary Cumulus-oocyte complexes were obtained from cows by aspiration of small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and processed for transmission electron microscopy after different periods of culture including a 0 h control group. In 0 h control oocytes the cumulus cells had numerous projections which penetrated the zona pellucida and established gap junctions with the oolemma. A partial loss of these junctions was noticed as an early event of oocyte maturation occurring within the first 3 h of culture. A low frequency of gap junctions was maintained until 12–18 h of culture where the junctional contact was completely disrupted. This decrease in intercellular communication was parallelled by resumption of oocyte meiosis.     

The expression of 3-fucosylated-N-acetyl lactosamine carbohydrate determinants in renal tumours

The distribution in renal tumours of 3-fucosyl-N-acetyl lactosamine has been studied by using the monoclonal antibodies AGF 4.36 and AGF 4.48 and immunoperoxidase methods on tissue sections. Seven of 19 nephroblastomas and 12 of 30 renal cell carcinomas contained the epitope. In nephroblastomas the epitope was found on the terminals of type B tubules in six cases and in one case on the type A or neoplastic tubules. In renal carcinoma the antigen was found on the surface of tumour cells. The results suggest that in kidneys bearing nephroblastomas ureteric bud elements may grow into the tumour from the adjacent kidney.     

Properties of neuronal activity related to a visual reaction time task in the monkey prefrontal cortex

1. Quantitative properties of neuronal activity related to a visual reaction time task were studied in the monkey prefrontal cortex. The task consisted of an initial waiting phase (3.0-s period), a warning phase (green lamp, a variable period of 1.5-3.5 s), a go phase (red lamp), and a reward phase. 2. A total of 189 task-related neurons showed 233 changes in discharge rates during the warning (n = 86), GO (n = 103), and reward (n = 44) phases of the task. Most of the task-related neurons (145/189, 77%) showed changes during only one of the task phases, and were designated W (warning phase)-type (n = 42), GO (go phase)-type (n = 59), and RE (reward phase)-type (n = 44) neurons. The remainder (n = 44, 23%) showed changes during both the warning and the go phases, and were designated WG (warning and go phase)-type neurons. In each phase, onset latencies, peak latencies, and decay times of each change were measured and compared. 3. The changes during the warning phase (n = 86) were separated into three groups based on decay time; that is, phasic changes (n = 31), phasic-tonic changes (n = 23), and tonic changes (n = 32). Onset latencies and peak latencies were homogeneously distributed, and there were no clear groupings, although phasic and phasic-tonic changes tended to show shorter latencies than tonic changes. 4. The changes during the go phase (n = 103) did not show distinct differences, either in terms of decay time or of latency. The changes during the go phase showed various degrees of coupling to both the visual go signal (GS) and lever-release hand movement. To quantitate the coupling, a value to indicate the degrees of coupling (coupling index) was calculated. The changes coupled more strongly to the GS (cue coupled), those coupled more closely to the lever release (movement coupled), and intermediate changes could be distinguished from each other. The cue-coupled changes showed shorter latencies from the time onset of the GS than the movement-coupled changes, and the intermediate changes showed intermediate latencies. The decay time and the duration of the intermediate changes were longer than those of the cue-coupled changes and the movement-coupled changes. 5. The properties of WG-type neurons were compared with those of W-type and GO-type neurons.(ABSTRACT TRUNCATED AT 400 WORDS)     

Neuroprotective properties of valproate

Neuropsychiatric disturbances are extremely common in Alzheimer’s disease (AD), and represent integral features of the illness, as well as appropriate targets for therapy. We are interested in designing trials aimed at preventing or delaying the emergence of psychopathology in AD. For symptomatic treatment of agitation, mood stabilizers, particularly sodium valproate, have proved to be beneficial in some patients. Since these effects take several weeks to emerge, we considered that they might be dependent on potentially neuroprotective actions of valproate, such as inhibition of apoptosis and slowing of neurofibrillary tangle formation. In this article we present the rationale for testing the neuroprotective potential of valproate experimentally in mouse models of tauopathy and in a clinical trial of patients with AD who lack psychopathology at baseline. Together, these studies will provide important tests of the hypothesis that valproate, either through inhibition of tau phosphorylation or some other mechanism, is a useful therapeutic agent to modify disease progression in AD.     

阴沟肠杆菌超广谱β—内酰胺酶、诱导酶的检出与耐药相关性的分析

目的：了解阴沟肠杆菌超广谱β－内酰胺酶和诱导酶的产生和分布情况。并分析产酶特性和耐药表型的相关性。方法：用纸片扩散确证法和相邻纸片法对104株阴沟肠杆菌进行超广谱β－内酰胺酶及诱导酶的检测，用VITEK全自动药敏分析系统和K－B琼脂扩散法检测其对20种抗生素的耐药性。结果：104例阴沟肠杆菌中，检出超广谱β－内酰胺酶阳性株77株，占74％，诱导酶阳性株26株，占25％，13株两种酶同时阳性。超广谱β－内酰胺酶阳性株主要集中在几个病区，诱导酶阳性株则无此倾向，104株菌对多种怀素高度耐药，产超广谱β－内酰胺酶株的耐药率明显高于非产酶株，产诱导酶株的耐药率反而低于非产酶株。结论：阴沟肠杆菌产酶情况和耐药性均十分严重。多重耐药的主要原因是由于菌株产生超广谱β－内酰胺酶，产酶株对三代头孢的体外敏感试验不能正确反映临床的治疗效果。实验室应加强阴肠杆菌产酶情况的检测，治疗产酶阴沟肠杆菌引起的感染，首选亚胺培南，其次为舒普深，任何情况下应避免使用三代头孢。