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Biomedical subjects

A M Levy

Publications and source records attributed to A M Levy.

42 records · Page 3Linked to original sources

Noninvasive recording of the His bundle electrogram in neonates.

Twenty-seven normal, nonsedated neonates had high-resolution electrocardiography performed during the first four days of life. Using high amplification, analogue and digital filters, and signal averaging, easily defined His bundle deflections of 0.75-7.75 (mean 2.5) microV were detected in 25 (92.6%) of the 27 babies. The PH interval was 60-105 (mean 83) ms and the HV interval 10-25 (mean 17) ms. Surface His bundle electrocardiography is easily performed in the neonate and, as might be predicted, conduction intervals are considerably shorter than those seen in older age groups.

Bundle of His↗

[Xenodiagnosis, hemoculture and the complement mediated lysis test, as criteria in selecting chronic chagasic patients for chemotherapy].

Normally specific treatment of chronic Chagas' disease begins only after a positive parasitological diagnosis has been established. Xenodiagnosis, hemoculture and complement mediated lysis were associated, and repeated, as an attempt to increase the number of selected candidates for specific treatment. Thirty six chronic chagasic patients were submitted to two series of the above tests, with a minimal interval of 60 days. In the first series of tests sensitivity of xenodiagnosis and hemoculture were 30.5% and 8.3% respectively. Processing of a second sample increased sensitivity to 36.1% (xenodiagnosis) and 19.4% (hemoculture); 47.2% were shown to be positive by at least one of these tests. From the positive cases, 29.4% were consistently negative in the complement mediated lysis test, and 17.6% exhibited discordant results, positive on one occasion and negative on the other. Among patients with negative parasitological tests, 47.4% had negative complement mediated lysis tests, 31.5% exhibited discordant results and 15.8% were positive. We conclude that complement mediated lysis test is not a method of choice in the selection of candidates for specific treatment of Chagas' disease in view of the observed variability of results. At this moment, parasitological test, in spite of a low sensitivity, are a safer tool for the clinician.

Animals↗

Effect of native chicken interferon on MDV replication.

Marek's disease virus (MDV) is an oncogenic alphaherpesvirus. Its specific phosphorylated protein, pp38 has been implicated in MDV oncogenesis. In order to check whether the known anti-viral or anti-proliferative actions of interferon (IFN) are of importance in Marek's disease (MD), chicken embryo fibroblasts (CEFs) were infected with attenuated serotype-1 MDV strain CVI988, or with herpesvirus of turkeys (HVT). Different concentrations of native chicken IFN were added to the cell cultures, prior to their infection. After incubation, MDV plaques were counted. Analysis by flow cytometry for pp38 expression was performed by using three monoclonal antibodies (MAbs) and for HVT by using an anti-glycoprotein B (gB) MAb. Increasing IFN quantities caused a reduction in a stepwise manner of plaque numbers as well as a suppression of pp38 and gB expression in the CVI988- and HVT-infected cells, respectively.

Animals↗