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M Rosenfeld

Publications and source records attributed to M Rosenfeld.

108 records · Page 6Linked to original sources

Left-right asymmetry of visual evoked potentials in brain-damaged patients: a mathematical model and experimental results.

The left-right asymmetry in the potential amplitude on the scalp was studied in poststroke patients by using flash visual evoked potential (VEP) and a numerical two-dimensional model of the head. The left-right asymmetry of the VEP was measured in three patients after thrombosis, in one after hemorrhage, and in one healthy subject. The numerical model used computed tomography images to define the different compartments of the head. The volume conductor equation for the potential distribution created by a dipole source in the occipital region was solved numerically with use of a finite volume method. Left-right asymmetry was calculated with several values of conductivity of the damaged region. The experimental results revealed a negative asymmetry in the three patients after thrombosis (i.e., the potential amplitude over the ischemic hemisphere was smaller than that over the intact hemisphere), whereas, in the patient after hemorrhage, a positive asymmetry was found. Nonsignificant left-right asymmetry was found in the healthy subject. The numerical model revealed that the electrical conductivity of the damaged tissue has a major effect on the left-right asymmetry. Negative asymmetry, such as that found for patients after thrombosis, was obtained when the conductivity of the damaged region was greater than that of the brain, whereas positive asymmetry (hemorrhage patient) was obtained when that conductivity was smaller than that of the brain. This finding indicates that the left-right asymmetry in the scalp VEP of patients after brain damage may be a result of changes in the conductivity of the volume conductor (the ischemic region) between the source and the electrodes.

Cerebrovascular Disorders↗

The Malta Project--a country freed itself of leprosy. A 27-year progress study (1972-1999) of the first successful eradication of leprosy.

The successful conclusion of the first leprosy eradication program carried out with combination therapy is reported. This program started in Malta in June 1972. It was based on extensive experimental and clinical studies and was formally concluded on 31 December 1999. No new infections occurred after the start of this 27-year progress report. The youngest patient was 16, and the eldest 83 years old. Of the total of 261 cases in the project, 201 had already received pretreatment [mainly with diaminodiphenylsulfone (DDS)] at the start. Sixty-one cases had no pretreatment. These were predominantly elderly patients who were late in deciding to have treatment. The very long follow-up period totaling 27 years was consistently maintained in order to be able to refute all potential objections empirically, e.g. with regard to relapses at a late stage. Besides the overall symptoms which are typical for the broad picture of leprosy, the involvement of the eyes was very striking (at least 50%). The therapeutic effect was of very rapid onset in these cases without surgery. Rifampicin (RMP) + isoniazid + prothionamide + DDS (trade name Isoprodian-RMP) was used as medication in a fixed combination. This fixed combination had already proved to be highly effective in the treatments during the course of the project, surprising therapy results (including lifesaving effects) were also noticed in other diseases.

Aged↗

Immunocytochemical analysis of cellular components in atherosclerotic lesions. Use of monoclonal antibodies with the Watanabe and fat-fed rabbit.

We have performed immunocytochemical investigations into the distribution of smooth muscle cells and macrophages in the atherosclerotic lesions of the Watanabe heritable hyperlipidemic (WHHL) and fat-fed rabbits. We used monoclonal antibodies specific for muscle cells and macrophages, the latter with a new macrophage-specific monoclonal antibody designated RAM11. Scattered macrophages were observed in the subendothelium in areas of grossly normal aorta. Raised lesions were divided into four major groups, based on qualitative aspects of cell localization: fatty streak, composed predominantly of macrophages; intimal thickening, composed predominantly of smooth muscle cells that displayed considerable morphological heterogeneity with an admixture of macrophages; early fibrous plaques, characterized by approximately equal numbers of smooth muscle cells and macrophages; advanced fibrous plaques, composed of a fibrous cap containing flat smooth muscle cells overlying a macrophage-rich zone of atheromatous debris. These studies demonstrate the nature of the lesions in the two rabbit models and the usefulness of monoclonal antibodies in analyzing the cellular composition of atherosclerotic lesions.

Animals↗

Use of a tissue-specific promoter for targeted expression of the herpes simplex virus thymidine kinase gene in cervical carcinoma cells.

Molecular chemotherapy strategies have been developed for a number of epithelial malignancies based on selective delivery and expression of a toxin-encoding gene into the cancer cells. To date, these strategies have not been explored in the context of carcinoma of the cervix, despite the fact that a variety of factors suggest this as an appropriate disease for this gene therapy approach. One limitation in this respect is that appropriate tissue-specific promoters for selective toxin gene expression have not been defined for cervical carcinoma. In this regard, the secretory leukoprotease inhibitor (SLPI) gene has been shown to be constitutively expressed in many epithelial carcinoma cells including the uterine cervix. Thus, we investigated the utility of the SLPI gene as a tissue-specific promoter for regulatory control of the herpes simplex virus thymidine kinase gene for in vitro treatment of cervical carcinoma cells. For this analysis, a gene construct was derived with the herpes simplex virus thymidine kinase gene under regulatory control of the 5' upstream regions of the SLPI gene. Transient transduction of three human cervical carcinoma cell lines with the SLPI-thymidine kinase (TK) construct was followed by treatment with the prodrug ganciclovir. Crystal violet staining was subsequently used to assess cell viability. In this analysis, it was shown that the SLPI-TK construct directed TK-mediated killing in two of three tested cervical cell lines, with the two cell lines being positive for SLPI. In addition, mixing experiments established that cervical carcinoma cells could exhibit a bystander effect which potentially augments the efficacy of molecular chemotherapy approaches. These findings may allow for the development of efficacious, target-specific, toxin gene therapy strategies for cervical carcinoma in human patients.

Carcinoma↗