Biomedical subjects
Publications and source records attributed to E Kahana.
Creutzfeldt-Jakob disease was studied among Libyan-born Israelis, in whom the disease appears with unusual frequency. Interviews with relatives of deceased victims revealed statistically significant clustering within families. The results suggest either a common source of exposure or a genetic influence on susceptibility to the virus.
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The relative frequency of aseptic meningoencephalitis (AME) was compared in populations of diverse origin, A countrywide search of Israel during 1969-1970 disclosed 1350 cases who fit strict diagnostic criteria. The average annual incidence was 21.6 per 100000 population. The total incidence was similar in Afro-Asian, Euro-American and Israeli Jewish groups but among Israeli Arabs, the incidence was apparently lower. Age-specific incidence showed a peak in infants under one year of age among Arabs and Afro-Asian Jews whereas Euro-Americans and Israeli Jews had a peak incidence at 5-9 years. Larger family size among Arabs and Afro-Asian Jews might account for the higher incidence in infants. Age-specific incidence may be a better index than total incidence of important differences in AME among various ethnic groups.
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The distribution of 24 HLA antigens of the A and B loci was investigated in 197 Israeli Jewish patients with multiple sclerosis (MS) from various Jewish ethnic origins including central and eastern Europe, countries bordering the Mediterranean, the Middle East and from native-born Israelis. The results were compared with the HLA antigen frequencies in a control sample of 455 unrelated individuals representing the general Jewish population. The frequency of HLA-Bw40 among all MS patients (15%) was significantly greater (P less than 0.001) than among the controls (7%). In contrast to the findings in MS patients from other populations, there was no increased frequency of A3 and B7 and Dw2 was present in only one out of 28 patients. The study showed a similar distribution of HLA-A and -B locus antigens, especially of Bw40, in Jews of diverse ethnic origins represented in the control group.
Available estimates of the frequency with which a patient with optic neuritis develops multiple sclerosis range from as low as 13% to as high as 87%. In an effort to obtain a better estimate, a nation-wide study of optic neuritis was carried out in Israel. Patients who fulfilled strict diagnostic criteria of optic neuritis were identified and examined periodically. Between 1955 and 1964, 105 patients were found and on the basis of these, the average annual age-adjusted incidence of optic neuritis in Israel was 0.56 per 10(5) population compared to 1.2 per 10(5) cases of multiple sclerosis per year, i.e. optic neuritis was about half as frequent as multiple sclerosis each year. As with multiple sclerosis, optic neuritis was more common in European immigrants to Israel than Afro-Asian immigrants. During a follow-up interval which ranged from 3.3 to 15.6 years (mean 9.5 years), at least 27 of the 105 patients developed multiple sclerosis (28%). A life-table analysis showed that after 10 years 32.3 +/- 5.6% of patients with optic neuritis would develop multiple sclerosis and, after 14 years, about half would develop multiple sclerosis. Risk of dissemination was highest in those who were youngest when optic neuritis developed. Neither sex nor ethnic background influenced risk significantly. Results of the present study support earlier work using life-table methods carried out in Hawaii which also showed that between 29 and 39% of patients with optic neuritis will develop multiple sclerosis within 10 years of onset. The life-table method is a better predictor of prognosis than newer laboratory techniques such as spinal fluid studies of IgG, kappa-lambda light chain ratios and serum/CSF IgG ratios.
A country-wide study of the frequency of amyotrophic lateral sclerosis (ALS) was undertaken in Israel for the period 1960-1970. Israel was chosen for this study because of its excellent medical facilities and detailed demographic information. Moreover, the population includes representative groups from all parts of the world for comparison of frequency. A wide variety of motor system disease was screened in all hospitals, clinics, and chronic care facilities in the country, death certificates were reviewed and physicians with a neurological practice were contacted to derive a tentative list of cases. Only those who fit strict clinical diagnostic criteria or had autopsy confirmation were included in estimates of prevalence and incidence. On January 1, 1965, the mid-point of the study, 62 patients with ALS were living in Israel. The age-adjusted prevalence of ALS on that date was 3 per 100,000 population. The average annual age-adjusted incidence for the period 1960-1970 was 0.78 per 100000 population )0.86 in males, 0.46 in females; ratio 1.9:1). There was no appreciable change in trend of incidence over the study interval. Age-specific incidence rates were similar in native-born inhabitants of Israel, immigrants from Europe and immigrants from Afro-Asian countries. The range in age-adjusted incidence among subgroups of immigrants to Israel from various countries was 0.25 to 1.20 per 100000 population but small numbers precluded testing the statistical significance of these rather narrow differences. Mean age at onset was 55.4 years for males and 52.4 years for females. The mean age at death was 60.2 for males and 58.0 for females. The average annual mortality from ALS was 0.58 per 100000 population. There were no familial aggregates of ALS in Israel and autopsy data showed no neurofibrillary changes, granulovacuolar or inclusion bodies. There are only a few other population studies of ALS in different regions of the world. The average annual incidence in these other studies ranged from 0.4 to 1.4 per 100000 population. Thus, the incidence in Israel falls within this narrow range. The present study lends further support to the impression that ALS has a remarkably uniform geographic distribution with Guam and the Kii peninsula of Japan being the only known areas with significantly high rates. If an environmental factor contributes to the pathogenesis of ALS, the factor must also have a uniform geographic distribution.