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Biomedical subjects

A Reshef

Publications and source records attributed to A Reshef.

At least 19 recordsLinked to original sources
PubMed2004

Cytomegalovirus encephalitis in an immunocompetent pregnant woman.

Presented here is the case of an immunocompetent pregnant woman with probable cytomegalovirus encephalitis. The clinical picture was characterized by diffuse headache, drowsiness and the development of an acute confused state. Diagnosis was based on the documentation of recent cytomegalovirus seroconversion with low avidity for the immunoglobulin G class antibodies. Initially, the diagnosis of encephalitis was challenging due to the subtle findings in cerebrospinal fluid and the normal electroencephalograph results. However, repeated tests revealed findings compatible with the diagnosis of encephalitis. Due to the suspicion of herpes simplex encephalitis the patient was treated with acyclovir. Within a few days rapid resolution of the fever and complete recovery were observed. Cytomegalovirus encephalitis should be considered early in the evaluation of pregnant women if appropriate clinical symptoms are present.

Acyclovir↗
PubMed2004

Use of human lice in forensic entomology.

Hematophagus arthropod bloodmeals may be useful in identifying individual hosts. To examine the application of human lice as a forensic tool, that is, as evidence of physical contact between individuals, body lice from a laboratory colony and head lice, collected from the head of infested children, were studied. The DNA profile of an individual was detectable in the pooled bloodmeals of two body lice, up to 20 h postfeeding. A mixed DNA profile of two hosts was identifiable in the pooled bloodmeals of three lice, for 3 h postfeeding. By pooling the bloodmeals of three adult and three nymphal head lice, a mixed DNA profile was obtained. These results indicate that, in criminal cases where there has been close contact between assailant and victim, louse bloodmeals should not be overlooked as potentially critical evidence.

Animal Feed↗
PubMed2003

Family-based and case-control study of catechol-O-methyltransferase in schizophrenia among Palestinian Arabs.

COMT is a ubiquitous enzyme crucial to catechol metabolism. The molecular basis of COMT thermolability, that leads to three to fourfold differences in enzyme activity, is due to a substitution of valine with methionine in the Val158/108Met polymorphism. Of special interest is the role of this gene in major psychoses especially since a microdeletion (22q11) containing the COMT gene (velo-cardio-facial syndrome) also carries with it several types of behavioral disorders, including an increased prevalence of schizophrenia. Almost 20 genetic studies have examined the role of COMT in schizophrenia with ambiguous results. Towards clarifying the role of this polymorphism in conferring risk for psychosis, we examined a large group of culturally and ethnically akin Palestinian Arab schizophrenic triads (N = 276) using both a case-control and family-based study. In 194 informative triads with at least one heterozygote parent, no preferential transmission of either COMT allele was observed in this sample (TDT statistic chi-square = 0.14 NS; 131 COMT valine alleles were transmitted and 125 alleles not transmitted). However, using a case-control design a significant increase (Likelihood ratio = 3.935, P = 0.047) in the valine allele was observed in the group of schizophrenic patients (N = 276) compared to an ethnically matched control group (N = 77). The association was stronger in female patients (P = 0.012) similar to other studies showing that some COMT behavioral effects are gender sensitive. In summary, by case-control design but not by a family-based study, there is a weak effect in female patients of the high activity COMT allele in conferring risk for schizophrenia.

Amino Acid Substitution↗
PubMed2003

Immunoglobulin E antibody reactivity to the major shrimp allergen, tropomyosin, in unexposed Orthodox Jews.

BACKGROUND: Assessment of allergic (IgE antibody-mediated) reactions to foods may become complicated by cross-reactivity that can occur among certain food families and between foods and seemingly unrelated allergens. OBJECTIVE: The allergenic properties of tropomyosin (muscle-derived protein) have been recently demonstrated in invertebrates such as cockroaches, dust mites, and shrimp. In view of a possible cross-reactivity between food allergens and related allergens from animal sources, we designed a study to assess IgE antibody reactivity to the major shrimp allergen, Pen a 1, in an unexposed population of Orthodox Jews, who observe Kosher dietary laws that prohibit eating shellfish. METHODS: Nine subjects, who reacted positively by skin tests to shrimp (Penaeus setiferous), were selected for the study. Subjects (two females, seven males) ranged in age from 14 to 32 years (mean 20.4). All subjects were strictly observant of Jewish tradition and had no prior exposure to seafood (regarded as a non-Kosher food). Serum was obtained from all the subjects and tested for IgE antibody reactivity to shrimp and dust mite. RESULTS: All subjects reported symptoms of perennial allergic rhinitis, five had history of asthma, atopic dermatitis, and/or sinusitis. All had positive skin prick tests to shrimp and house dust mite (HDM) (Dermatophagoides farinae, D. pteronyssinus, or both); 2/7 subjects were positive to cockroach mix (Blattella germanica and Periplaneta americana). Sera of 4/9 subjects demonstrated specific IgE antibodies by RAST to shrimp (7.0-20.0%), 3/9 to Pen a 1 (6.3-24.1%), and 3/9 to shrimp or Pen a 1 by immunoblot. IgE binding to Pen a 1 was inhibited with either mite or cockroach extracts as demonstrated by RAST and/or immunoblot inhibition analysis. CONCLUSIONS: These studies indicate that IgE antibody reactivity to a major food allergen, shrimp, can occur in an unexposed population of individuals; some subjects allergic to HDM and/or cockroach show substantial IgE antibody reactivity to the major shrimp allergen Pen a 1 (tropomyosin). Based on inhibition with cockroach and/or dust mite extracts, this reactivity appears to be due to cross-reacting tropomyosins.

Allergens↗
PubMed2001

No evidence for linkage by transmission disequilibrium test analysis of microsatellite marker D22S278 and schizophrenia in a Palestinian Arab and in a German population.

Linkage for a schizophrenia susceptibility locus on chromosome region 22q12-q13 was initially suggested by independent studies from two groups and confirmed in a combined analysis of data for the microsatellite marker D22S278 in multiply affected schizophrenic families derived from 11 independent research groups worldwide. In addition to these reports of linkage to schizophrenia on chromosome 22, bipolar disorder has also been linked to markers in this chromosomal region. We now report results from an analysis of 223 Palestinian Arab trios from three different centers in Israel and Palestine using the allele-wise extended transmission disequilibrium test for multiallelic markers. No evidence for linkage is observed in the entire group or in any of the three centers (entire group: chi-square = 5.59, P = 0.78, df = 9; Afula: chi-square = 6.51, P = 0.48, df = 7; Bethlehem: chi-square = 14.11, P = 0.12, df = 9; Beersheva: chi-square = 7.04, P = 0.32, df = 6). Additionally, we examined D22S278 in a group of 114 schizophrenic German triads and failed to observe evidence for linkage (chi-square = 8.13, P = 0.42, df = 8df).

Alleles↗
PubMed2001

A family-based study of the Cys23Ser 5HT2C serotonin receptor polymorphism in schizophrenia.

The 5HT2C receptor has a high affinity for clozapine, a nontypical neuroleptic, and has therefore been postulated to play a role in mediating negative symptoms and neuroleptic response in schizophrenia. In the current study, the Cys23Ser 5HT2C serotonin receptor polymorphism was examined for linkage to schizophrenia by genotyping 207 nuclear families consisting of both parents and schizophrenic child and using the transmission disequilibrium test to examine possible preferential transmission of these alleles from 68 heterozygous mothers to their ill child. No evidence was obtained for preferential transmission of the Cys23Ser 5HT2C alleles in schizophrenia in either of the two main ethnic groups examined (German and Palestinian Arab) or in the combined cohort (TDT chi-square = 0.00, NS).

Adolescent↗
PubMed2001

The hypereosinophilic syndrome associated with CD4+CD3- helper type 2 (Th2) lymphocytes.

We describe herein the clinical and laboratory manifestations of a unique group of patients (pts) presenting with hypereosinophilic syndrome (HES) who were treated in our medical centers for 4-13 years. Skin biopsies, flow cytometry of peripheral blood mononuclear cells (PBMC), assays for cytokines and immunoglobulin (Ig) production in vitro, and Southern blots of T-cell receptor (TCR) genes were performed. All four pts had a persistent hypereosinophilia (> 1.9 x 10(9)/L) and chronic skin rash. Three of four had elevated IgE, thrombotic manifestations and lung involvement (asthma and/or infiltrates), and one had deforming sero-negative arthritis of the hands. 66-95% of their peripheral T-cells expressed CD4 but not CD3 or TCR molecules on the cell surface membrane. Activated CD4+CD3- cells secreted interleukin (IL)-4 and/or 5, and were required for maximal IgE secretion by autologous B-cells. Two pts had evidence of rearrangement of TCR genes of the CD4+CD3- cells, one of whom died of anaplastic lymphoma. In conclusion, HES with CD4+CD3- lymphocytosis may be associated with high serum IgE, dermatological, pulmonary, thrombotic and rheumatic manifestations which may be due to Th2 effects of CD4+CD3- cells migrating to end organs. Fatal systemic lymphoid malignancy may also develop in some pts with monoclonal expansion of the CD4+CD3- T-cells.

Adult↗
PubMed2001

DNA profiling of trace evidence--mitigating evidence in a dog biting case.

A young girl was the victim of a severe dog attack. An animal, suspected of having caused the attack, was later impounded for investigation. Microclots of blood, recovered from the dog's fur, were analyzed by STR DNA. Results showed that this blood was not related to the biting. Other forensic evidence--hairs, fibers, and odontology--failed to connect a particular animal to the attack. The implications of these findings for the dog and its owners are discussed as well as other forensic methods for resolving such cases.

Animals↗
PubMed2000

No association between the dopamine D3 receptor Bal I polymorphism and schizophrenia in a family-based study of a Palestinian Arab population.

Several recent meta-analyses appear to show a weak but significant effect of both forms of the gly/ser DRD3 polymorphism in conferring risk for schizophrenia. Since most studies have employed the artifact-prone case-control design, we thought it worthwhile to examine the role of this polymorphism using a robust family-based strategy in an ethnic group not previously systematically studied in psychiatric genetics, Palestinian Arabs. We failed to obtain any evidence in 129 Palestinian triads, using the haplotype relative risk (allele frequency: Pearson chi-square = 0.009, P > 0.1, df = 1, n = 258 alleles) or transmission disequilibrium test design (chi-square = 0.38, P > 0.1, n = 86 families) for association/linkage (or increased homozygosity) of the DRD3 Bal I polymorphism to schizophrenia in our sample. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:778-780, 2000.

Alleles↗
PubMed2000

Ischemic tolerance conferred to cultured rat neurons by heat shock is not mediated by opening of adenosine triphosphate-sensitive potassium channels.

The effect of sublethal heat shock on the capacity of neurons to resist subsequent ischemia-reperfusion-induced cell injury, was studied in a model of primary rat neuronal cultures, subjected to chemical ischemia. Exposure of the cultures to sublethal heat shock (42 degrees C; 20 min) resulted in elevation in cellular content of heat shock protein (HSP)-70, at 4 h following the shock, and in acquisition of a 15 h 'time window of protection' against ischemia-reperfusion insult, with maximum protection at 4 h. Presence in the culture medium of glibenclamide (2 microM), a blocker of ATP sensitive potassium (K(ATP)) channels, did not abolish the acquisition of protection throughout the entire duration of the acquired 'time window of protection'. The results demonstrate that heat shock induces in neurons a protective mechanism against ischemia-reperfusion insult, probably associated with enhanced expression of HSPs, which does not depend on opening of K(ATP) channels. In this respect, the neuronal 'heat-shock mechanism' for the acquisition of ischemic tolerance differs from the neuronal 'adenosine mechanism' and probably also from the heart 'heat shock mechanism' for the acquisition of protection.

Adenosine Triphosphate↗
PubMed2000

Opening of K(ATP) channels is mandatory for acquisition of ischemic tolerance by adenosine.

Binding of adenosine to neuronal adenosine receptors activates a signal transduction pathway (the adenosine mechanism), leading to a temporary ischemic tolerance. We have demonstrated before that induction of this mechanism in primary rat neuronal cultures, by activation of adenosine receptors, or by activation of protein kinase C (PKC), confers a wide time window of ischemic tolerance, lasting up to 72h, the early (immediate) part of which depends on opening of K(ATP) channels (glibenclamide sensitive). Here we demonstrate that the entire duration of the ischemic tolerance conferred by activation of the adenosine mechanism depends on opening of the K(ATP) channels. Thus, opening of the K(ATP) channels appears to be a mandatory step in the adenosine mechanism, leading to the creation of the wide time window of ischemic tolerance.

Adenosine↗
PubMed2000

[Recurrent anaphylactic reactions during hospitalization--an unusual etiology].

The prevalence of hypersensitivity and untoward reactions to natural rubber latex (NRL) products is increasing, particularly among specific risk groups. A young man aged 23 years who experienced several episodes of allergic reactions, 2 of which included anaphylactic shock during hospital admission, is presented. These episodes were initially attributed to intravenous medication, but were most probably caused by inadvertent exposure to latex. Medical facilities may contain large amounts of latex, and therefore present a hazardous environment for sensitive people. Increasing awareness of latex sensitivity among patients-at-risk and medical personnel, and implementing simple prophylactic measures, may reduce morbidity and mortality. We propose simple and practical guidelines for diagnosis and treatment.

Adult↗
PubMed2000

A cholesterol-lowering gene maps to chromosome 13q.

A cholesterol-lowering gene has been postulated from familial hypercholesterolemia (FH) families having heterozygous persons with normal LDL levels and homozygous individuals with LDL levels similar to those in persons with heterozygous FH. We studied such a family with FH that also had members without FH and with lower-than-normal LDL levels. We performed linkage analyses and identified a locus at 13q, defined by markers D13S156 and D13S158. FASTLINK and GENEHUNTER yielded LOD scores >5 and >4, respectively, whereas an affected-sib-pair analysis gave a peak multipoint LOD score of 4.8, corresponding to a P value of 1.26x10-6. A multipoint quantitative-trait-locus (QTL) linkage analysis with maximum-likelihood binomial QTL verified this locus as a QTL for LDL levels. To test the relevance of this QTL in an independent normal population, we studied MZ and DZ twin subjects. An MZ-DZ comparison confirmed genetic variance with regard to lipid concentrations. We then performed an identity-by-descent linkage analysis on the DZ twins, with markers at the 13q locus. We found strong evidence for linkage at this locus with LDL (P<.0002), HDL (P<.004), total cholesterol (P<.0002), and body-mass index (P<.0001). These data provide support for the existence of a new gene influencing lipid concentrations in humans.

Adult↗
PubMed1999

Impact of different low-density lipoprotein (LDL) receptor mutations on the ability of LDL to support lymphocyte proliferation.

Based on the demand for cholesterol for membrane formation, we determined the ability of low-density lipoprotein (LDL) to support proliferation in lymphocytes bearing different LDL receptor mutations, which were treated "in vitro" with lovastatin to inhibit endogenous cholesterol synthesis. Peripheral lymphocytes were isolated from two patients with homozygous familial hypercholesterolemia (FH), one homozygote for the mutation N804K (FH(Colmenar)) in exon 17, herein described for the first time, and a compound heterozygote carrying the mutations D280G and G528V, which determine a transport-defective biochemical phenotype. Flow cytometric analysis with 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanineperchlorate (Dil)-LDL showed normal LDL binding but defective internalization in lymphocytes from case 1, whereas in lymphocytes from case 2 both LDL binding and internalization were affected. Studies with mitogen-stimulated lymphocytes demonstrated that despite the different phenotype, the ability of LDL to support proliferation was impaired in both cases to a similar extent. These results indicate that internalization of the LDL particle is required for expression of the mitogenic effect of LDL.

Adolescent↗
PubMed1999

Chorionic villus sampling prior to pregnancy termination, a tool for forensic paternity testing.

Chorionic villus sampling (CVS), prior to pregnancy termination (pre-termination CVS), is suggested as a tool for forensic paternity testing. Unlike the abortion material, which consists of ruptured tissues of fetal and maternal origin, extra-embryonic membranes obtained through CVS can provide an uncontaminated source of fetal tissue for genotyping. We discuss the possibility of confined placental mosaicism (CPM) and its implications on the polymerase chain reaction (PCR) based analyses of short tandem repeats (STRs) and the D1S80 loci.

Abortion, Legal↗
PubMed1998

Opening of ATP-sensitive potassium channels by cromakalim confers tolerance against chemical ischemia in rat neuronal cultures.

The effect of opening and of blocking of ATP-sensitive potassium (K(ATP)) channels on the short-term capacity of neurons to resist ischemia-reperfusion-induced cell injury, was studied in a model of primary rat neuronal cultures, subjected to metabolic poisoning by iodoacetic acid (150 microM, 150 min), followed by reperfusion (1 h). The metabolic poisoning resulted in a marked decrease in cellular ATP content (from 65.3 +/- 13.4 to 21.6 +/- 11.7 nmole/mg protein), simulating an ischemia, or hypoxia-induced condition of energy crisis. The degree of neuronal damage was assessed by the trypan blue exclusion test. Exposure of the neurons to the channel-opener cromakalim (10 microM; 15 min), prior to the insult, induced resistance, which could be abolished by the specific channel blocker glibenclamide (2 microM). Glibenclamide also abolished the protection acquired by preconditioning of the neurons with iodoacetate (IA; 100 microM), the adenosine A1 agonist N6-(R)-phenylisopropyladenosine (R-PIA; 100 microM), or with the protein kinase C (PKC) activator 1,2 dioctanoyl-rac-glycerol (DOG; 1 microM). The results indicate that in the neurons, opening of the K(ATP) channels confers protection against an ATP-depleting crisis, and suggest that the protective effects induced by adenosine and by activation of PKC, are mediated by the opening of these channels.

Adenosine Triphosphate↗
PubMed1998

Markedly reduced bile acid synthesis but maintained levels of cholesterol and vitamin D metabolites in mice with disrupted sterol 27-hydroxylase gene.

Sterol 27-hydroxylase is important for the degradation of the steroid side chain in conversion of cholesterol into bile acids and has been ascribed a regulatory role in cholesterol homeostasis. Its deficiency causes the autosomal recessive disease cerebrotendinous xanthomatosis (CTX), characterized by progressive dementia, xanthomatosis, and accelerated atherosclerosis. Mice with a disrupted cyp27 (cyp27(-/-)) had normal plasma levels of cholesterol, retinol, tocopherol, and 1,25-dihydroxyvitamin D. Excretion of fecal bile acids was decreased (<20% of normal), and formation of bile acids from tritium-labeled 7alpha-hydroxycholesterol was less than 15% of normal. Compensatory up-regulation of hepatic cholesterol 7alpha-hydroxylase and hydroxymethylglutaryl-CoA reductase (9- and 2-3-fold increases in mRNA levels, respectively) was found. No CTX-related pathological abnormalities were observed. In CTX, there is an increased formation of 25-hydroxylated bile alcohols and cholestanol. In bile and feces of the cyp27(-/-) mice only traces of bile alcohols were found, and there was no cholestanol accumulation. It is evident that sterol 27-hydroxylase is more important for bile acid synthesis in mice than in humans. The results do not support the contention that 27-hydroxylated steroids are critical for maintenance of cholesterol homeostasis or levels of vitamin D metabolites in the circulation.

Animals↗