A stereological study of the human ovarian surface epithelium.

The surface of the ovary has been found to be composed of two types of epithelial cells called A and B cells which are found in their own respective zones, the A and B zones. A quantitative study was undertaken to determine the mean cell volumes and cell ultrastructure. Ovarian biopsies were taken from six women and A and B zones, having been identified by scanning electron microscopy, were re-embedded for transmission electron microscopy. Stereological measurements using point sampled intercepts were made on vertical sections and showed that B cells are significantly larger than A cells. The volume weighted mean cell volumes of the A and B cells were 237.3 microns 3 and 676.8 microns 3 respectively. The volume fractions of the nucleus and mitochondria were similar in the two cell types. Although the vesicle content of each type was similar, a large variation between cases made the interpretation difficult. The stereological tools used in this study proved to be easy and efficient estimators of surface cell ultrastructure and give an important direction for ultrastructural research.     

突触小泡膜表面突起与微管联系的超微结构研究

本研究用透射电镜技术观察了大脑皮质（视区）和海马（CA1区和CA3区）的神经终末内的突触小泡和微管间的联系。结果揭示：在适当的超薄切片样品上，常显示出突触小泡膜表面上有短的突起，说明突触小泡是借其膜表面的短突与其它小泡和微管进行联系的。除小泡外，在微管的表面也见一些短突并与小泡发生接触。本文首次报道了用透射电镜方法观察脑内小泡-微管借表面短突连接的联系，提示突触小泡膜表面和微管表面的短突在轴浆运输机制中负有重要的作用。     

Urethral closure function in women with prolapse

In 19 patients with different types of severe descensus, all without clinical evidence of stress incontinence, urethral stress pressure profiles and stress tests were done before and after repositioning of the prolapse. In 13 of the 19 patients, continence was artificial, because during repositioning they showed leakage of urine; however, 6 of the patients remained continent. The pressure transmission ratios decreased in different parts of the urethra in all the patients when repositioning with a gynecological speculum was done. The drop was most significant in those patients who lost urine after repositioning, showing poor urethral function. In women with genito-urinary prolapse, a test of urethral function is essential, even if there is no clinical evidence of incontinence after removal of the descensus. In cases of severe stress incontinence under this condition, a procedure for bladder neck stabilization should be added to routine prolapse surgery.     

Imaging studies of the cadaver hand using transmission ultrasound

Ultrasonic transmission imaging has already demonstrated potential for evaluating structures in the hand. In this study, a cadaver hand was imaged using a transmission scanner with improved imaging capability. The hand was then frozen and serially sectioned and comparisons were made between the sectional anatomy and the corresponding image. Bone (in silhouette), muscle, cartilage, and tendon were visualized with high resolution.     

慢性HBV感染患者精子中HBVDNA存在研究的初步报告

用Southern Blot方法,我们研究了13份慢性HBV感染患者(8份慢迁旰,5份慢活肝)和2份对照精液标本中HBV DNA存在状况。提取物一半用限制酶HindⅢ消化,各行琼脂电泳,转移到纤维膜上,然后用~(32)P—HBV—DNA探针分子杂交。在4份精子內检出HBV DNA,3份为游离形式,1份为整合形式。结果表明HBV DNA可以存在精于内,游离状态HBV DNA提示有传染性、整合序列HBV DNA的存在提示有通过生殖细胞遗传的可能。     

Conditions to optimise the reversal action of neostigmine upon a vecuronium-induced neuromuscular block

Background: Since neostigmine was introduced for reversal of neuromuscular block, there has been controversy about the optimum dose for antagonizing neuromuscular block. The purpose of this study was to characterise recovery of neuromuscular transmission following a vecuronium-induced block 15 min after neostigmine administration using different stimulation patterns, and to determine the effects of different doses of neostigmine given at various pre-reversal twitch heights. Methods: Adductor pollicis (AP) mechanical activity in response to low (0.1 and 2 Hz) and high (50 and 100 Hz) frequency stimulation, was recorded 15 min after 20, 40 and 80 μg/kg neostigmine, given to reverse a vecuronium-induced block at 10, 25 and 50% pre-reversal twitch height (TH). Fifty four ASA class I and II anaesthetised (methohexital, fentanyl, N₂O/O₂) young adult patients were studied and randomly allocated into 9 groups of 6 patients each. Results: In contrast to twitch height (TH) and residual force after 50 Hz, 5 s tetanic stimulation (RF50_Hz), the greater sensitivity of train-of-four (TOF) ratio and residual force after 100 Hz, 5 s tetanic stimulation (RF100_Hz) points out the best reversal conditions (prereversal TH and the optimal neostigmine dose) (P<0.001, two-way analysis of variance). The highest reversal scores (about 0.9 TOF ratio and RF100_Hz) were obtained when 40 μg/ kg of neostigmine was given at 25 and 50% TH. A 0.9 TOF ratio was also observed when 40 μg/kg of neostigmine was given at 10% TH, but, under these conditions, RF100_Hz was only 0.6 (P<0.05, Duncan test). Conclusion: To optimise the reversal action of neostigmine in order to obtain the highest neuromuscular transmission recovery (0.9 TOF ratio and RF100_Hz) during a vecuronium-induced neuromuscular block, the 40 μg/kg dose has to be given at 25 to 50% recovery of TH.     

Serotonergic modulation of neurotransmission in the rat subicular cortex in vitro: a role for 5-HT1B receptors

Summary We have studied the effect of serotonin on synaptic transmission in rat hippocampal subiculum slices. Electrical stimulation of the alveus induced a field potential in the subiculum. The non-NMDA glutamate receptor antagonist, NBQX (3 × 10^–6 mol/l) suppressed the response by 78%, indicating that the signal involves glutamatergic neurons. Application of serotonin suppressed (EC₅₀ = 3.6 × 10^–6 mol/l) the amplitude of he evoked potentials in a reversible, concentration-dependent manner. The responses to 5-HT were not altered after pretreatment with the 5-HT uptake blocker, fluvoxamine (10^–5 mol/l) or a combination of the MAO inhibitor pargyline (10^–5 mol/l) and ascorbic acid (10^–4 mol/l). The responses to 5-HT were also unaffected by pretreatment with the 5-HT_1A selective antagonist NAN-190 (10^–6 mol/l), the 5-HT_2A antagonist ketanserin (10^–6 mol/l) or the 5-HT₃/5-HT₄ antagonist ICS 205–930 (10^–6 mol/l).The 5-HT_1B selective agonist CP 93,129 mimicked the effects of serotonin, but was more potent (EC₅₀ 4.1 × 10^–7 mol/l). The 5-HT_1B receptor antagonist, (±)21-009 (3 × 10^–7 mol/l), antagonized the response to 5-HT and CP 93,129 with a pK_B value of 7.1 and 7.2, respectively. These results suggest that the effect of 5-HT in the rat subiculum is mediated by 5-HT_1B receptors.Correspondence to: H.W.G.M. Boddeke at the above address     

Block of the endplate acetylcholine receptor channel by the sympathomimetic agents ephedrine, pseudoephedrine, and albuterol

Recent observations suggest that some patients with congenital myasthenic syndromes respond favorably to ephedrine, pseudoephedrine, or albuterol. Conventional microelectrode studies, however, provide no clear explanation for a beneficial effect of ephedrine in endplate diseases. To gain further insight into how these drugs affect neuromuscular transmission, we investigated their effects on the kinetic properties of the acetylcholine (ACh) receptor. Single channel currents were recorded from rat lumbrical muscles endplates using low concentrations of ACh and 2.5–100 μM of drugs. Between 10–100 μM, each drug progressively increased the rate of channel closure in a concentration dependent manner, consistent with an open-channel block. Albuterol acted as a sequential fast-acting channel blocker, increasing the mean burst duration in a concentration dependent manner without altering the total open time per burst or the duration of intraburst blockages. Increasing concentrations of ephedrine and pseudoephedrine also increased the number of intraburst closures but decreased the total open time per burst. None of the drugs altered single channel conductance. The channel blocking effects of ephedrine and pseudoephedrine might reduce the synaptic overactivity that occurs in the slow-channel myasthenic syndromes or in endplate ACh esterase deficiency, but these effects occur at concentrations not attainable in clinical practice.     

Significance of antibodies to the recombinant E2 protein of hepatitis G virus in haemodialysis patients

Patients on maintenance haemodialysis represent a high-risk group for parenterally transmitted viral infections, such as hepatitis B, C and G. In addition to hepatitis G virus (HGV) (GBV-C) RNA, analysed in previous studies, we characterized the seroprevalence rates of antibodies to the putative E2 protein (anti-E2) of HGV in a German cohort of patients on maintenance dialysis ( n = 72) in comparison to healthy blood donors ( n = 100). The presence of anti-E2 and/or HGV RNA as indicators of present or past HGV infection could be demonstrated in 34.7% of patients and in 16% of the blood donors ( P < 0.01). The infection rates with HGV seem to increase only during the first 6 years of haemodialysis. The simultaneous presence of viraemia and anti-E2 was found very rarely in patients and controls. Therefore, the emergence of anti-E2 indicates clearance of HGV viraemia. In conclusion, patients on haemodialysis are at high risk of acquiring HGV infection, but a chronic carrier state with viraemia is rare. The risk of infection is not strictly correlated with the duration of dialysis.