Biomedical subjects
Publications and source records attributed to V Misra.
Congenital abnormalities induced by murine cytomegalovirus have previously been suggested to be an indirect effect of maternal illness as no infectious virus has been isolated from the foetus. However, in this article we report that latent virus detectable by immunofluorescence and in situ hybridization, may frequently be present in foetal tissues.
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Spleen cultures from various strains of mice were infected in vitro with murine cytomegalovirus (MCMV). Infectious centres were established in a small proportion (not greater than 1%) of the cells. Virus could be rescued from these cells by co-cultivation with syngeneic or allogeneic fibroblasts, but the frequency of rescue could not be altered by incubation with cyclic nucleotide analogues, iododeoxyuridine, cortisol, or allogeneic spleen cells. In addition a smaller fraction of the cell population, possibly a sub-population of the infectious centres, replicated virus spontaneously. The presence of mitogens did not affect these interactions qualitatively or quantitatively. A third response to infection was an inhibition in DNA synthesis, which was suffered by unstimulated cultures and by cells transformed by concanavalin A and bacterial lipopolysaccharides, although overall cell viability was maintained. This response was also mediated by u.v.-inactivated virus.
Murine cytomegalovirus RNA synthesis in productively infected mouse embryo cultures was measured by reassociation kinetics with iodinated viral DNA. The data were analyzed by a computer program and indicated the following: before DNA replication approximately 25% of the genome was transcribed into asymmetric transcripts, of which slightly fewer than half of the sequences were recovered from the cytoplasm. After viral DNA replication, approximately 38% of the genome was transcribed (5% as symmetric transcripts), and again less than half of the sequences appeared in the cytoplasm. Both early and late RNA comprised two abundance classes differing about 8- to 10-fold in concentration. Early RNA was a subset of late RNA. The RNE sequences synthesized in late-infected cells in the presence of cytosine arabinoside or cycloheximide were similar to early RNA. Thus, murine cytomegalovirus displays temporal, quantitative, and post-transcriptional controls over gene expression, but the pattern differs considerably from herpes simplex virus.
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A line of murine cytomegalovirus (MCMV)-resistant cells was derived from mouse embryo cultures. The virus penetrated the nuclei of these resistant cells efficiently and a small amount of viral gene transcription occurred, although no viral DNA synthesis was detected. Synthesis of cellular DNA, RNA and protein continued unabated, and the infected cells grew at the same rate as uninfected cells. The block in virus replication in these cells appears to be between early transcription and viral DNA synthesis.
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To assess reliability of the endoscopic and histologic appearance of the gastric mucosa for diagnosing portal hypertension, 50 patients with portal hypertension and 1323 controls were studied. Endoscopic evidence of mild gastritis was seen more frequently in patients with portal hypertension than in the control group (42% vs. 13.1%, p less than 0.001). The mosaic sign was also seen more frequently in patients with portal hypertension compared with controls (14% vs. 0.9%, p less than 0.001). However, the mosaic sign was found to be nonspecific, and the sensitivity for diagnosis of portal hypertension was only 14%. Biopsy specimens from the stomach of all patients with portal hypertension and 100 controls with a normal endoscopic appearance revealed mucosal vascular congestion in 72% of patients with portal hypertension compared with 59% of controls (NS). There was no correlation between endoscopic and histologic evidence of congestive gastropathy. Similarly, there was no correlation between the severity of mucosal vascular congestion and the degree of inflammatory changes observed in the biopsy specimens; both in the control (r = 0.1) and in patients with portal hypertension (r = 0.14). It is concluded that endoscopic and histologic features of the gastric mucosa in patients with portal hypertension are of low sensitivity and nonspecific and cannot be used to diagnose portal hypertension.
Loeffler's methylene blue, commonly used as a counter-stain for acid fast bacilli, was used to detect Helicobacter pylori in paraffin sections and touch smears of gastric mucosal biopsies from 15 patients with duodenal ulcer and 35 with non-ulcer dyspepsia, and the results were compared with the modified Giemsa stain. The time taken to stain smears by Loeffler's methylene blue was approximately 10 min and the results correlated well with those stained by the modified Giemsa stain. However, the Loeffler's methylene blue method was found to be simpler, quicker and cheaper than the modified Giemsa stain.
Ascitic fluid total protein, albumin, cholesterol, their ascites/serum ratios, serum-ascites albumin and cholesterol gradients were measured for their ability to differentiate cirrhotic, malignant and tuberculous ascites in 76 patients. The mean +/- s.d. ascitic fluid total protein, albumin, cholesterol, their respective ascitic fluid/serum ratios in cirrhotic ascites were lower than malignant and tuberculous groups (P < 0.001 for each). The difference between malignant and tuberculous groups was significant for ascitic fluid/serum total protein (P < 0.05) and ascitic fluid/serum albumin (P < 0.01) only. Mean serum-ascites albumin gradient in cirrhotics was higher than in the malignant and tuberculous groups (P < 0.001 for each). The difference between malignant and tuberculous groups was significant (P < 0.01). Mean +/- s.d. serum-ascites cholesterol gradient in cirrhotics was higher than that in malignant and tuberculous groups (P < 0.001 for each). The difference between malignant and tuberculous groups was also significant (P < 0.01). Both serum/ascitic fluid total protein less than 0.5 and ascitic fluid cholesterol less than 55 mg/dL had 94% diagnostic accuracy for differentiating cirrhotic from malignant and tuberculous differentiating cirrhotic from malignant and tuberculous ascites. Serum ascitic fluid albumin gradient greater than 1.1 g/dL, ascitic fluid/serum albumin less than 0.65 and ascitic fluid albumin less than 2 g/dL had diagnostic accuracy of 92, 92 and 91%, respectively. Ascitic fluid total protein had diagnostic accuracy of 88%. None of the tests was able to differentiate between malignant and tuberculous ascites. Measurement of ascitic fluid cholesterol concentration is a simple method of differentiating cirrhotic from non-cirrhotic ascites.
OBJECTIVE: To assess the role of fine needle aspiration biopsy (FNAB) in patients with palpable colonic masses. STUDY DESIGN: FNAB was performed on 32 patients with palpable colonic masses before subjecting them to colonoscopic examination. Smears prepared from the material obtained by aspiration biopsy were examined. The results of aspiration biopsy were confirmed by histopathologic examination of the tissue obtained on colonoscopy or surgery or by a salutory response to antituberculous therapy in patients with tuberculosis of the colon. RESULTS: Twenty-nine patients had carcinoma of the colon, and three had ileocecal tuberculosis. Aspiration biopsy could correctly diagnose all the cases with malignancy and two of the three cases with colonic tuberculosis. Colonoscopy could not be performed on two patients with cancer of the colon. However, a barium enema examination revealed evidence of cecal malignancy in both patients. In the two patients diagnosed as having colonic tuberculosis by FNAB, colonoscopic biopsies revealed only nonspecific changes. There were no false positive results or complications of the procedure. CONCLUSION: FNAB is a simple, rapid and accurate method of diagnosing palpable colonic masses.
OBJECTIVE: To report a case of acute toxicity in a patient with chronic verapamil toxicity, possibly precipitated by intravenous administration of the highly protein-bound drugs ceftriaxone and clindamycin. DATA SOURCES: Case reports, review articles, and relevant laboratory and clinical studies identified by MEDLINE (1984-forward), and relevant cross references from those articles. DATA EXTRACTION: Data were abstracted from pertinent sources by one author and reviewed by the remaining authors. CASE SUMMARY: A 59-year-old man who had been receiving sustained-release verapamil 240 mg q12h for more than two years for hypertension, and phenytoin 300 mg/d for many years for prophylaxis against seizures, was noted to be in junctional rhythm when he presented to the emergency room with bilateral pneumonia. Administration of intravenous ceftriaxone 1 g and clindamycin 900 mg precipitated symptoms of acute verapamil toxicity in this patient. The toxicity led to complete heart block requiring cardiopulmonary resuscitation and insertion of a temporary pacemaker. He spontaneously reverted to normal sinus rhythm after 16 hours. Subsequent cardiac evaluation, including echocardiogram, 48-hour dynamic electrocardiographic recording (Holter), and exercise stress test were normal. The patient has remained in sinus rhythm for more than one year after this episode. CONCLUSIONS: We believe that junctional rhythm on admission was a result of chronic verapamil toxicity. This may have been because of increased bioavailability of the drug or increased sensitivity of the receptors. Administration of ceftriaxone, clindamycin, or both agents might have precipitated acute verapamil toxicity by displacing verapamil from its protein-binding sites. Extreme caution is necessary when a highly protein-bound drug is given to a patient already receiving verapamil.