Biomedical subjects

T Shohat

Publications and source records attributed to T Shohat.

At least 55 records · Page 3Linked to original sources

PubMed1996

Determination of immunity to measles virus in young adults: comparative evaluation of a commercial enzyme immunoassay and the hemagglutination inhibition techniques.

BACKGROUND: Determination of the immune status against measles in young adults requires careful evaluation of the laboratory methods because of waning immunity. The hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA) may lack the sensitivity required to detect very low levels of antibodies. In addition, the correlation between ELISA-IgG assays and the degree of protection from measles is not well defined. OBJECTIVES: (a) Evaluation of a commonly used measles ELISA-IgG test kit in comparison with the hemagglutination inhibition (HI) test which corresponds strongly to virus neutralization; (b) determination of false negative rates of the ELISA-IgG and the HI tests; (c) evaluation of the ELISA-IgG test kit as a quantitative assay. STUDY DESIGN: One hundred and eighty serum samples collected from 60 vaccinated young adults immediately before vaccination and 14 and 28 days postvaccination, were tested comparatively by HI and by a commercial ELISA-IgG kit. For evaluation of false negative rates, postvaccination sera of a cohort of 48 vaccinees with negative HI or ELISA-IgG prevaccination sera were tested for IgM. Sixty-three of the samples were also titrated by the ELISA-IgG kit using serial dilutions, for comparison with HI titers. RESULTS: Using the HI test as a reference method, the ELISA-IgG kit was found to have overall accuracy of 81%, sensitivity of 80% and specificity of 84%. The false negative and the false positive rates were 20% and 16%, respectively. In contrast, when we used postvaccination IgM test to distinguish between true and false prevaccination negatives in both the HI and ELISA-IgG tests, we found that the false negative rates were 75.6% by ELISA and 72.5% by HI, and false positive rates were 2.4% and 0%, respectively. Serum titers determined by the ELISA-IgG test were generally 5-10-fold higher than the corresponding HI titers, but without a consistent correlation. CONCLUSIONS: Both the ELISA-IgG and the HI tests frequently failed to detect residual immunity. The two tests also did not correlate well with each other suggesting that different antigenic determinants of the virus are involved in each assay and therefore the HI test should not be used as a reference method for evaluation of the sensitivity of ELISA IgG kits.

Adolescent↗

PubMed1995

Familial Mediterranean fever: high gene frequency among the non-Ashkenazic and Ashkenazic Jewish populations in Israel.

Familial Mediterranean fever (FMF) is an autosomal recessive recurrent episodic inflammatory disorder that occurs with high frequency in certain populations in the Mediterranean area. Using extended pedigree data of 90 FMF probands, we calculated the FMF gene frequency in various ethnic groups in Israel by analyzing the frequency in a total of 2,312 first cousins. The heterozygote frequencies were as follows: 1:4.9 (0.2 +/- 0.06) for the Libyan subgroup, 1:6.4 (0.16 +/- 0.03) for the other North African countries subgroup, 1:13.3 (0.07 +/- 0.04) for the Iraqi subgroup, 1:11.4 (0.09 +/- 0.06) for the Ashkenazic subgroup, and 1:29.4 (0.03 +/- 0.03) for the remaining ethnic groups. The observed number of affected parents and offspring of the probands was in agreement with the estimated gene frequency. Thus, the FMF gene frequency is very high in all Jewish ethnic groups in Israel, especially those originating in North African countries. This also explains the parent-to-off-spring transmission of FMF reported in North-African Jews.

Africa, Northern↗

PubMed1994

Increased risk for type I (insulin-dependent) diabetes in relatives of patients with alopecia areata (AA).

The prevalence of various chronic diseases was compared in 517 individuals with alopecia areata, and 2,969 of their first degree relatives. As previous reports have suggested an increased incidence of diabetes in relatives of patients with alopecia areata, special attention was given to the prevalence of Type 1 and Type 2 diabetes in the patients and in their relatives. Several immunologic diseases were increased in alopecia probands and relatives. Thyroid disease, vitiligo, Addison disease, and pernicious anemia were more prevalent in probands and in their relatives than in the general population. Specifically, a high rate of thyroid disease was found in probands (14.7%) and in their first degree relatives (4.2%). Only one proband had Type 1 diabetes, yet there were 14 sibs with Type 1 diabetes. Thus, Type 1 diabetes was significantly more prevalent in the sibs (1.2%) than in either the probands with alopecia (0.2%), or the general population (0.12-0.25%) (P < 0.05)). In contrast, Type 2 diabetes was not more common in probands or in sibs than in the general population. These data suggest that alopecia areata protects against Type 1 diabetes in predisposed individuals. The high rate of thyroid disease suggests that screening probands and first degree relatives for thyroid disease should be considered.

Addison Disease↗

PubMed1994

Sex differences in the humoral antibody response to live measles vaccine in young adults.

BACKGROUND: Following vaccination of children using high-titre live measles vaccine, excess non-specific mortality was reported, particularly among females. Since vaccination with live measles virus results in a temporary depression of the immune response to other antigens, the female predominance in subsequent non-measles mortality may be due to sex differences in response to live measles vaccines. METHODS: In this study, the immunogenicity of standard titre live Schwarz strain measles vaccine was examined 2 and 4 weeks post-vaccination in 223 males and 66 female aged 18-20 years in Israel in 1991. RESULTS: Females had higher post-vaccination geometric mean titre (GMT) at all levels of pre-vaccination titres at both 2 and 4 weeks. Furthermore, after controlling for differences in pre-vaccination titres, overall the post-vaccination GMT for females was about 50% higher than for males (P < 0.001). CONCLUSIONS: These findings indicate that females exhibit a stronger humoral immune response to measles vaccine. Possible sex differences in immunosuppression following measles vaccination should be explored.

Adolescent↗

PubMed1994

Incidence of diabetes mellitus in various population groups in Israel (1989 and 1990).

A prospective survey of all newly diagnosed insulin-dependent diabetes mellitus (IDDM) children and adolescents aged 0-17 years in Israel was conducted for the years 1989 and 1990. All diabetic clinics in Israel treating young diabetics were contacted and they returned written reports to us. Each clinic was also visited regularly by a member of the team who reviewed the individual charts to obtain data on population origin as well as medical and demographic data. A total of 187 patients were identified (164 Jews and 23 Arabs), giving a total incidence rate of 5.46/10(5). Analysis of the incidence rates by population groups showed that Arabs and Jews originating in Asia had the lowest incidence (2.77 and 4.58/10(5) respectively), followed by Jews whose fathers were born in Israel (5.61/10(5)). The highest incidence was registered for Jews originating from Europe and North America (9.34/10(5)). The female-to-male preponderance ratio was higher in the Jews originating in Asia (2.1) than in Jews originating in Europe and North America (1.2). Comparing the present data with a survey performed for the years 1975-80 we found a statistically significant increase in incidence in all population groups. Our findings strongly suggest an influence of genetic factors on the incidence of childhood IDDM.

Adolescent↗

PubMed1994

Measles immunity in Israeli young adults: effects of second immunization at 18 years of age.

Measles morbidity and mortality in Israel have declined since the introduction of routine vaccination, even though measles continues to occur in epidemic cycles. In this study we examined the antibody response to measles revaccination, and the effect of prior administration of immune serum globulin (ISG) on the antibody response to measles vaccine. A study group of 312 young adults in army service received the Schwartz strain measles vaccine. Serum antibody levels were studied prior to vaccination and 2 and 4 weeks after vaccination. The finding of this study show that: a) booster response occurs in those vaccinees shown to have low or undetectable prerevaccination titers of measles antibodies; b) there is no effect of administration of ISG, prior to vaccination, on the antibody response to measles vaccine; and c) at the present level of immunity to measles in the Israeli adolescent population, we still may witness periodic epidemics in populations at risk.

Adolescent↗

PubMed1994

Further mapping of the properdin deficiency gene in a Tunisian Jewish family--evidence for genetic homogeneity.

The properdin deficiency gene has been localized to Xp21.1-Xcen; however, it is not clear whether the mutation responsible for the disease co-maps exactly with the structural properdin gene. Based on a recent study on a total of six families, the gene was found linked to DXS255 (theta = 0.00). As only a few families have been studied, it is not known whether the same gene is responsible for the disease in all families. In order to better localize the disease gene in Israel, we studied a Tunisian Jewish family with properdin deficiency for linkage with various X-markers. A maximum lod score of 1.93 at theta = 0.00 was calculated with the DXS7 probe while there was one recombination with DXS255. This study helps to better localize the properdin deficiency gene to Xp11.3-p21.1 proximal to DXS255 locus and confirms that there is no indication of genetic heterogeneity. Whether the properdin structural gene (PFC) and properdin deficiency locus are one and the same await demonstration of mutations in the structural gene in patients with properdin deficiency.

Chromosome Mapping↗

PubMed1994

Clinical, serological and molecular characteristics of 471 hepatitis B virus carriers.

A total of 471 Israel Defense Forces (IDF) blood donors identified as hepatitis B virus (HBV) carriers were examined a few months after blood donation. When compared to the general population of IDF blood donors the HBV carriers were older, belonged to certain ethnic groups and were predominantly males. Physical examination revealed minimal findings: 1 (0.3%) had splenomegaly and 5 (1.6%) had hepatomegaly. Fifty-two individuals (11.1%) had elevated liver enzymes. E antigen was present in 3.2% of HBV carriers, 94% had anti-e antibodies and 1.9% had anti-delta antibodies. Of 258 carriers tested for HBV DNA, 29 (11.2%) were positive. Abnormal liver enzymes were significantly associated with the presence of e antigen as well as with the presence of HBV DNA.

Adult↗

PubMed1993

Efficacy of different doses of immune serum globulin in the prevention of hepatitis A: a three-year prospective study.

Previous studies have shown that the administration of immune serum globulin (ISG) before exposure to hepatitis A virus prevents infection. The precise dose needed and the duration of the protection conferred are unclear, however. In this study, ISG doses of 2 mL and 5 mL were used for preexposure prophylaxis, and their efficacies in reducing the attack rate of hepatitis A among Israel Defence Forces troops serving in field units were compared. The attack rate during the first 4 months of follow-up was low and was similar regardless of the dose administered (0.11/10,000 and 0.15/10,000 for 2 mL and 5 mL, respectively; P = 1.0). In the second and third 4-month intervals after immunization, attack rates were higher (but not significantly so) among soldiers given 2 mL than among those given 5 mL. Twelve months after immunization, the cumulative attack rate for hepatitis A was significantly different for the two groups (2.78/10,000 vs. 1.30/10,000; P < .05). Our data suggest that preexposure immunization with 2 mL of ISG is as effective as that with 5 mL in preventing hepatitis A for 4 months. The advantage of the 5-mL dose is evident 5-12 months after administration.

Dose-Response Relationship, Immunologic↗

PubMed1992

Thirty years of experience with infectious hepatitis prevention in the Israel Defence Forces.

Infectious hepatitis is endemic to Israel. Large outbreaks of infectious hepatitis were common in the Israel Defence Forces (IDF) before 1970, at which time post-exposure prophylaxis with immune serum globulin was introduced. It caused a decrease in the incidence of infectious hepatitis from 10-14/1,000 to 3/1,000. A further reduction in incidence was achieved after 1978 when a policy of pre-exposure prophylaxis was established. The number of yearly outbreaks and cases per outbreak also declined as a result of this policy. Worldwide studies have shown that a policy of pre-exposure prophylaxis and/or post-exposure prophylaxis with immune serum globulin is effective in reducing the incidence of infectious hepatitis. The experience of the IDF is that a combination of both pre-exposure and post-exposure prophylaxis is more efficacious. This policy should be worthwhile in other areas where infectious hepatitis is endemic.

Adult↗

PubMed1992

The gene for familial Mediterranean fever in both Armenians and non-Ashkenazi Jews is linked to the alpha-globin complex on 16p: evidence for locus homogeneity.

Familial Mediterranean fever (FMF) is a recurrent inflammatory disorder characterized by short episodes of fever, peritonitis, pleuritis, and arthritis. While FMF has been shown to be inherited in an autosomal recessive fashion in both non-Ashkenazi Jews and Armenian families, clinical differences have raised the possibility of genetic heterogeneity. As its pathogenesis is unknown, mapping of the gene for FMF may provide the first objective method for early and accurate diagnosis of this disease. After excluding 45% of the entire human genome, we studied 14 Armenian and 9 non-Ashkenazi Jewish families with FMF and tested linkage with the alpha-globin locus on chromosome 16. Analysis of the PvuII length polymorphism of the 3' HVR (hypervariable region) probe showed significant linkage with the FMF gene (maximum lod score [lodmax] = 9.76 at maximum recombination fraction [theta] = .076). In the Armenians, the lodmax = 3.61 at theta = .10; and for the non-Ashkenazi Jews, lodmax = 6.28 at theta = .06. There was no evidence for genetic heterogeneity between the Armenians and the non-Ashkenazi Jews (chi 2 = 1.28; P = .26) or within either ethnic group (chi 2 = .00; P = .50). Thus, the gene for FMF is linked to the alpha-globin complex on chromosome 16p in both non-Ashkenazi Jews and Armenians.

Armenia↗

PubMed1992

The epidemiology of injuries sustained by Israeli troops during the unrest in the territories administered by Israel, 1987-89.

Information on 1,267 Israeli soldiers injured in the administered territories (West Bank and Gaza) between December 1987 and November 1989 as a result of the Palestinian unrest was retrieved by us. The cases were divided according to cause, body location and severity of the injury. Most of the injuries were caused by stones (62%), the head being the primary site of injury (50.3%). Although the majority of injuries were light (92.3%), there was a 1.1% fatality rate. Enforcement of orders requiring troops to use protective gear that is issued to them would reduce the number and severity of the injuries.

Humans↗

PubMed1992

Civil unrest and ocular trauma.

The incidence and causes of ocular trauma among Israeli troops serving in the West Bank and Gaza between 1987 and 1989 was investigated. Of the 985 soldiers who were reported injured, 11.3% (111) were reported to have suffered from injuries to the eye. Although most of the soldiers were supplied with some kind of protective gear, only 27% reported that they received eye protection; none used this protection at the time of injury. Fifty-seven percent of the injuries were caused by stones and 38% by flying glass; 14.6% of soldiers suffered bilateral eye injuries. Only 12.1% of those injured wore corrective lenses. Although only 5% were originally reported to have suffered moderate to severe injuries, 38% complained of residual vision impairment. Better eye protection and enforcement of orders to use such gear would reduce the number and severity of ocular injuries.

Civil Disorders↗

PubMed1990

Rearrangement of chromosome 15 in the region q11.2----q12 in an individual with obesity syndrome and her normal mother.

Rearrangement of the proximal long arm of chromosome 15 have been found in most patients with the Prader-Willi syndrome (PWS) and in some with Angelman syndrome. We present an individual with syndromic obesity and her normal mother, who both have an abnormal chromosome 15. The proposita is a 26-year-old women with marked obesity, acanthosis, nigricans, short fingers, and severe cone degeneration of the retina. She has high plasma insulin levels, hypothyroidism, and an empty sella on CT scan. High-resolution chromosome banding demonstrated an increase in band 15q12. Further analysis showed the same abnormal 15 in her normal mother but not in her normal sister. This case and recent reports in the literature indicate that duplication of chromosome 15q in the PWS region may be associated with a syndrome of obesity, acanthosis nigricans, empty sella, and rodcore dystrophy as well as with a normal phenotype. Whether normal individuals with such a duplication carry increased risk of having offspring with an obesity syndrome is yet to be determined.

Acanthosis Nigricans↗

PubMed1990

Serum amyloid A and P protein genes in familial Mediterranean fever.

Two recent studies have suggested the involvement of serum amyloid A (SAA) and P (APCS) genes in familial Mediterranean fever (MEF). To test the role of SAA and APCS in MEF and MEF-amyloidosis, we studied 17 informative families (15 Armenians, 2 non-Ashkenazi Jews) and 8 MEF patients with amyloidosis using a candidate gene approach. No evidence for any MEF-associated polymorphism was found in any of the 41 Armenian and Jewish MEF patients tested. Our family studies allowed us to rule out tight linkage between SAA and MEF (lod score = -2.16, theta less than or equal to 0.06). For APCS we found that the allele frequency in the MEF-amyloidosis patients was similar to that in 18 unrelated MEF patients without amyloidosis and their 33 healthy parents. Finally, we excluded close genetic linkage between APCS and MEF at 8.5 cM or less (lod score = -2.2).

Alleles↗

PubMed1990

Genetic marker family studies in familial Mediterranean fever (FMF) in Armenians.

Familial Mediterranean fever is an autosomal recessive disease manifested by recurrent short episodes of fever associated with polyserositis. It is common in a variety of Mediterranean and near Eastern populations. The biochemical defect is unknown, and there have been few studies of genetic marker associations or linkage with the disease. We have screened blood samples from members of 14 nuclear Armenian families, the population with the highest known gene frequency, for 19 different polymorphic phenotypic genetic markers. These 14 families included 31 affected and 43 unaffected family members. No association was found with any of the markers studied. Linkage could be excluded at the distance of 0-15% recombination with 14 markers. Linkage could not be excluded with 5 other markers. These results exclude the FMF gene from those portions of the human gene map that are at least 0.5% recombination distance from these 14 genetic markers, and represent the first comprehensive step in the eventual localization and isolation of the FMF gene.

Armenia↗

PubMed1990

Familial Mediterranean fever--linkage studies with genetic markers on chromosome 6.

Familial Mediterranean Fever (FMF) is an autosomal recessive disease manifested by recurrent short episodes of fever associated with polyserositis. Although the biochemical defect is unknown, there are several immunologic abnormalities which have been described in this disease. To examine critically whether there is linkage between FMF and the immunogenetic region (major histocompatibility complex-MHC) on chromosome 6, including the HLA, BF, and GLO1 loci, blood samples from members of 13 nuclear Armenian families were tested for these genetic markers. These 13 families included 28 affected and 42 unaffected family members. Linkage could be excluded at 7.5% recombination with the HLA ABC and D loci. Linkage could be excluded at 2.5% recombination for GLO1. Linkage could not be excluded with BF individually, but can be rejected based on the haplotype data. No association was found with either BF, GLO1, and HLA DQ alleles. HLA DR4 was found more often in affected cases than in controls; however, after adjusting for the number of antigens tested this was not significant. Our results would appear to exclude the immunogenetic region on chromosome 6 from linkage with FMF in the Armenian population.

Alleles↗

PubMed1989

Hypertension in Israeli adolescents: prevalence according to weight, sex and parental origin.

We studied the prevalence of hypertension in 57,499 male and 35,803 female Israeli military recruits and its relation with sex, weight, and parents' ethnic origin. The overall prevalence of systolic hypertension (greater than 140 mmHg) was 1.75 per cent for males and 0.32 per cent for females. The prevalence of diastolic hypertension (greater than 90 mmHg) was 0.41 per cent for males and 0.06 per cent for females. For males, the prevalence of systolic and diastolic hypertension increased with weight, exponentially. Males of Ashkenazi origin had a significantly higher prevalence of hypertension (systolic 2.52 per cent, diastolic 0.55 per cent) compared with those of Sephardi origin (systolic 1.12 per cent, diastolic 0.3 per cent). The prevalence of adolescents with systolic or diastolic blood pressure greater than the mean +2SD of each weight group ranged between 1.5-2.3 per cent.

Adolescent↗