Regulation of muscarinic receptors by intrahippocampal injections of gallamine.

Multiple intrahippocampal injections of gallamine impair performance of a representational memory task in rats. The binding of [3H]-(-)-quinuclidinyl benzilate (QNB) to rat brain sections was measured to determine if changes in receptor binding were associated with the deleterious effects of gallamine. [3H]-(-)-QNB binding to sections taken from gallamine-injected animals was compared with binding in saline-injected control animals. Autoradiographic analyses indicated an increase in [3H]-(-)-QNB binding sites within all layers of the cerebral cortex and in the superior colliculus in gallamine-treated animals as compared to saline-injected controls. Significant increases were noted in cortical layers IV and V (P less than 0.025) in gallamine-treated animals. No significant changes (P greater than 0.05) in the number of binding sites were observed in the hippocampus, neostriatum or various thalamic nuclei. The ability of unlabeled pirenzepine, gallamine and carbamylcholine to inhibit 0.2 nM [3H]-(-)-QNB binding also was measured to determine changes in the distribution of receptor subtypes. No significant changes were observed in any brain region for the binding of the selective antagonists pirenzepine and gallamine or the agonist carbamyl-choline. Although other possibilities are considered, the data suggest that an increase in the number of muscarinic receptors may contribute to the observed behavioral deficits associated with long-term gallamine treatment.     

舌黏膜尿道成形治疗尿道狭窄的初步报告

目的:探讨舌黏膜补片法尿道成形治疗尿道狭窄的疗效。方法:采用舌黏膜尿道成形治疗尿道狭窄14例。尿道狭窄段3.5~14cm,平均6.2cm;术前耻骨上膀胱造瘘8例,余6例排尿均较为困难,最大尿流率2.5~5.5ml/s,平均3.8ml/s。结果:术后随访2~8个月,1例因伤口感染致尿道皮肤瘘,余患者均排尿通畅,最大尿流率增至22~51ml/s,平均29.6ml/s。结论:舌黏膜具有取材方便、对患者创伤小、抗感染力强等特点,是一种较好的尿道替代物,尤其适合尿道狭窄段<6cm的患者。     

MRI of the fingers in patients with systemic scleroderma. Early results of contrast-enhanced examinations on a dedicated MRI system

Purpose. To estimate disease activity in patients with systemic sclerosis using contrast-enhanced MRI of the skin. Material and Methods. In a pre-study, sequences of a low-field (0.2 T) scanner (Artoscan, Esaote, Genova, Italy) were optimized for detection of intravenous contrast (0.1 mmol/l Gd-DTPA) in six patients with the autoimmune disease systemic scleroderma. Based on the results of the pre-study, 17 patients with scleroderma (7 sclerotic/10 active inflammatory disease) were scanned using gradient-spoiled 3D GRE sequences (FA 90 °, TR 100 ms, TE 18 ms), which had been established as most sensitive for intravenous contrast. Contrast enhancement of the skin was determined quantitatively by contrast-to-noise ratios (CNR), comparing post- to pre-contrast and dynamic scans (for 6 min, 1 acquisition/min). Patients in the chronic state with sclerodactylia and active inflammation of the hands were considered separately and compared to a control group (n = 10) matched according to age. Results. CNR increase after intravenous contrast was significantly higher in patients with active disease (86 ± 16 % increase) than sclerosing disease (29 ± 3 %, p < 0.05) and the control group (4 ± 2 %, p < 0.05). The dynamic examination showed a significantly slower decrease after the peak rise in the first minute in patients with active disease (CNR 15.4 ± 0.7 to 14.2 ± 1.4) than in those with chronic disease (14.1 ± 0.5 to 11.3 ± 0.9, p < 0.05). Discussion. Capillary leakage is the most likely explanation for the increased enhancement in patients with active scleroderma. Using sequences optimized for contrast detection, disease activity in the course of scleroderma and response to therapy can be determined by MRI in the future.      

Suppurative corneal ulceration in Bangladesh

Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.     

Evidence for proteolytic cleavage of the 120-kilodalton outer membrane protein of rickettsiae: identification of an avirulent mutant deficient in processing.

The 120-kDa rickettsial outer membrane protein (rOmpB) is encoded by a gene with the capacity to encode a protein of approximately 168 kDa. The carboxy-terminal end of the molecule is apparently cleaved to yield 120- and 32-kDa products. Both polypeptides are surface exposed and remain associated with the outer membrane of intact rickettsiae. All species of rickettsiae examined display similar cleavage of rOmpB. Comparison of diverse species of rickettsiae demonstrate a conserved N terminus of the 32-kDa fragment, with a predicted procaryotic secretory signal peptide immediately upstream of the proposed cleavage site. Coprecipitation of the 120-kDa rOmpB protein and the 32-kDa peptide by monoclonal antibodies specific for the 120-kDa portion of the molecule suggests that the two fragments remain noncovalently associated on the surface of rickettsiae. Analysis of an avirulent mutant of Rickettsia rickettsii revealed reduced amounts of the 120- and 32-kDa fragments, but with a correspondingly larger rOmpB protein that displayed properties expected of the putative precursor. This avirulent mutant grows intracellularly but fails to cause the lysis of infected cells that is typical of R. rickettsii. DNA sequence analysis of the region of the gene encoding the cleavage site of the avirulent strain revealed no difference from the sequence obtained from virulent R. rickettsii. The 168-kDa putative precursor of the avirulent strain of R. rickettsii was not extracted from the surface by dilute buffers, as is the 120-kDa protein of virulent R. rickettsii or R. prowazekii. These latter results suggest that the 32-kDa C-terminal region of the molecule may serve as a membrane anchor domain.     

Behavior, genetics and biochemistry of an allele of the mutant mouse spastic, spaAlb

A new autosomal recessive mutation, characterized by an early defect in righting reflex and stiffened gait, progression to severe spasticity, tremor and rigidity, and death before weaning, appeared spontaneously on the C57BL/6 background. It was shown to be an allele of the mutant spastic spa, and shall be known as spaAlb. Mutant levels of [3H]strychnine binding are less than 10% of control levels in the brainstem and spinal cord. Autoradiographic examination of the distribution of [3H]strychnine binding sites in the mutant confirm a greatly reduced level of binding compared to control in all areas of the spinal cord, brainstem, and midbrain.