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Biomedical subjects

M Levin

Publications and source records attributed to M Levin.

At least 145 records · Page 8Linked to original sources
PubMed1995

Evidence for a superantigen mediated process in Kawasaki disease.

The clinical, pathological, and immunological similarities between Kawasaki disease and the staphylococcal and streptococcal toxic shock syndromes suggest that a superantigen toxin may be involved in the pathogenesis of the disease. The V beta repertoire of peripheral blood mononuclear cells from 21 children with Kawasaki disease, 28 children with other illnesses, and 22 healthy controls were examined using monoclonal antibodies to V beta 2, 5, 8, 12, and 19. The mean percentage of V beta 2 expressing T cells in the patients with Kawasaki disease was increased when compared with healthy controls or children with other illnesses. The mean percentages of V beta 5, 8, 12, and 19 expressing T cells were also increased in the patients with Kawasaki disease compared with healthy controls, but were not increased when compared with children with other illnesses. The selective use of V beta 2 supports the hypothesis that a superantigen is involved in the pathogenesis of Kawasaki disease.

Acute Disease↗
PubMed1995

Evidence for exclusion of a mutation in NRAMP as the cause of familial disseminated atypical mycobacterial infection in a Maltese kindred.

In mice, susceptibility to intracellular infections in inbred strains is controlled by a single locus, Lsh/Ity/Bcg, and the gene responsible has been cloned and designated Nramp (Natural resistance associated macrophage protein). We have identified a group of related children who appear to have a single gene defect, inherited recessively, which results in increased susceptibility to myocabacterial infection. The immunological defect observed in the affected children resembles that in mice homozygous for the Lsh/Ity/Bcg susceptible allele. To test the hypothesis that a mutation in NRAMP is responsible for the immunodeficiency observed in the affected children, we have typed eight markers in the region of human 2q34-q37 where NRAMP, the human homologue of Nramp, maps. We have shown discordance with the defect in one family and the chromosomes in the three affected children have different haplotypes making it unlikely that inheritance of an ancestral mutation in the NRAMP gene is the cause of increased mycobacterial susceptibility in this group of children.

Animals↗
PubMed1995

Cytokine production in varicella-zoster virus-stimulated lymphocyte cultures.

Among varicella-zoster virus (VZV)-immune adults aged 20 to 35 years, T lymphocytes producing interferon-gamma (IFN-gamma) in response to a VZV antigen stimulus are eight times more numerous than those making interleukin-4 (IL-4). In persons over 55 years old, the frequency of IFN-gamma-making cells falls while the number of IL-4-making cells remains roughly constant. The persistence of IL-4-making cells may contribute to the maintenance of IgG antibodies to VZV with aging.

Adult↗
PubMed1995

HIV/AIDS knowledge among the U.S. population.

This analysis examines knowledge of HIV and AIDS among 71,370 persons interviewed in a national sample of the U.S. population. Factor analysis of 26 questions about HIV infection and AIDS identified four distinct dimensions of AIDS knowledge: 1) transmission mechanisms; 2) commonly known nontechnical information; 3) definitions of AIDS; and 4) technical information. Significant differences across racial, ethnic, socioeconomic, and demographic groups exist for each dimension of AIDS knowledge. In general, racial minorities and those with lower socioeconomic status are shown to have lower knowledge levels. Exposure to mass media about AIDS, and knowing a person with HIV or AIDS, are also strong predictors of increased knowledge. Multivariate analysis demonstrates 1) that socioeconomic status is a better predictor of knowledge of AIDS than race or ethnicity; and 2) exposure to AIDS mass media has the strongest effect on all dimensions of AIDS knowledge except for knowledge of technical issues about AIDS. Policy implications of these results are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Production of tissue factor by monocyte progenitor cells.

Tissue factor (TF) is known to be produced by monocytes from human peripheral blood. However the production of this factor by haematopoietic progenitor cells is not yet known. We thus studied human monocyte progenitor cells isolated from bone marrow of normal and diseased individuals. These cells were non-adherent, monocytic and able to phagocytose particles ranging from 0.3-1 microns. Unactivated partial thromboplastin time clotting assay demonstrated procoagulant activity consistent with TF function, which was blocked by a neutralizing anti-TF monoclonal antibody, G12. The production of TF messenger RNA was demonstrated on dot blot and northern blot analysis utilizing an oligonucleotide probe.

Adult↗
PubMed1994

Endotoxin-induced neutrophil adherence to endothelium: relationship to CD11b/CD18 and L-selectin expression and matrix disruption.

The injury to vascular endothelium seen in severe bacterial infection may be mediated by neutrophil-derived enzymes. Neutrophil adhesion to endothelium, a prerequisite for this process, is mediated sequentially by the leukocyte adhesion molecules L-selectin and the beta 2 integrins, including CD11b/CD18. We have explored the relationship between expression of these molecules, neutrophil adherence, endothelial activation, and consequent endothelial injury, as assessed in vitro by changes to HS and FN matrices that colocalize. Endothelial prestimulation with LPS (endotoxin) caused an increase in adherence and an inversely proportional disruption in the HS matrix; disruption of the FN matrix only occurred on the further addition of fMLP. Although maximal changes in these matrices were associated with elevation of neutrophil CD11b/CD18 and reduction in L-selectin expression, these changes did not determine either the nature or extent of endothelial damage. CD11b/CD18 expression was similar in both adherent and nonadherent neutrophils, while L-selectin was shed in association with adherence in the absence of other stimuli. These changes in expression were thus independently regulated. This model may provide further insights into the interrelationship between neutrophil adhesion and activation and endothelial damage in infection with gram-negative bacteria.

Antigens, CD↗
PubMed1994

Industrial hygienist as a clinical consultant.

The roles of industrial hygienists outside the traditional industrial setting have been expanding. This paper discusses the industrial hygienist's direct and active involvement with patients in the clinic setting. The types of roles played by the industrial hygienists in an occupational health clinic are categorized based upon experience in one academic clinic. Although experience demonstrated that there is an important function for the industrial hygienist as a clinical consultant, unresolved issues, ranging from payment to staff privileging, interfere with widespread participation.

Adult↗
PubMed1994

Kaposi's sarcoma of the bone marrow presenting with fever of unknown origin.

Kaposi's sarcoma (KS) has become more common in the United States with the spread of the Acquired Immunodeficiency Syndrome (AIDS) epidemic. The epidemic form associated with AIDS involves primarily skin and visceral organs. Bone marrow involvement is rare. We present a case of Kaposi's sarcoma that was diagnosed upon bone marrow biopsy, without skin or visceral involvement, that presented with fever of unknown origin which responded to indomethacin and anti-KS chemotherapy. Kaposi's sarcoma of the bone marrow should be considered in the differential of febrile illness of unknown origin in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Syndromes with renal failure and shock.

Renal failure occurs commonly in children with shock, coagulopathy and multi-organ failure. Successful management of these patients requires not only management of the renal failure, but recognition and treatment of the underlying process. In addition to common and well-recognised causes of renal failure and shock, such as Gram-negative sepsis, there are a number of syndromes which are either less well recognised or confined to specific geographic locations. This article reviews the clinical and epidemiological features of the syndromes with shock and renal failure, focusing on the more recently recognised syndromes such as staphylococcal and streptococcal toxic shock syndrome, haemorrhagic shock and encephalopathy syndrome and viral haemorrhagic fevers.

Acute Kidney Injury↗
PubMed1994

Familial disseminated atypical mycobacterial disease.

Mycobacterial disease remains a major public health problem and there appears to be a genetic component underlying susceptibility. This paper describes a group of related children who appear to have a genetic predisposition to disseminated atypical mycobacterial infection. Identification of the defect in this group could lead to better understanding of the genetics of susceptibility to mycobacterial infection.

Child, Preschool↗
PubMed1994

A Julia set model of field-directed morphogenesis: developmental biology and artificial life.

One paradigm used in understanding the control of morphogenetic events is the concept of positional information, where sub-organismic components (such as cells) act in response to positional cues. It is important to determine what kinds of spatiotemporal patterns may be obtained by such a method, and what the characteristics of such a morphogenetic process might be. This paper presents a computer model of morphogenesis based on gene activity driven by interpreting a positional information field. In this model, the interactions of mutually regulating developmental genes are viewed as a map from R2 to R2, and are modeled by the complex number algebra. Functions in complex variables are used to simulate genetic interactions resulting in position-dependent differentiation. This is shown to be equivalent to computing modified Julia sets, and is seen to be sufficient to produce a very rich set of morphologies which are similar in appearance and several important characteristics to those of real organisms. The properties of this model can be used to study the potential role of fields and positional information as guiding factors in morphogenesis, as the model facilitates the study of static images, time-series (movies) and experimental alterations of the developmental process. It is thus shown that gene interactions can be modeled as a multi-dimensional algebra, and that only two interacting genes are sufficient for (i) complex pattern formation, (ii) chaotic differentiation behavior, and (iii) production of sharp edges from a continuous positional information field. This model is meant to elucidate the properties of the process of positional information-guided biomorphogenesis, not to serve as a simulation of any particular organism's development. Good quantitative data are not currently available on the interplay of gene products in morphogenesis. Thus, no attempt is made to link the images produced with actual pictures of any particular real organism. A brief introduction to top-down models and positional information is followed by the formal definition of the model. Then, the implications of the resulting morphologies to biological development are discussed, in terms of static shapes, parametrization studies, time series (movies made from individual frames), and behavior of the model in light of experimental perturbations. All figures (in grayscale), formulas and parameter values needed to re-create the figures and movies are included.

Computer Simulation↗
PubMed1994

Antibodies to beta-adrenergic receptors disclosing agonist-like properties in idiopathic dilated cardiomyopathy and Chagas' heart disease.

Recent studies confirm the existence of antibodies (Abs) to beta-adrenoceptors in patients with idiopathic dilated cardiomyopathy and Chagas' heart disease. These Abs can be shown to exert both stimulatory and inhibitory effects, which may play a role in the development of the cardiac abnormalities known to occur in these diseases, including advanced heart failure. The hypothesis is advanced that Chagas' heart disease and some forms of idiopathic dilated cardiomyopathy may represent, at least partially, a form of "adrenergic cardiomyopathy."

Animals↗
PubMed1994

Simultaneous occurrence of chronic myelogenous leukemia and signet-ringed adenocarcinoma of the rectum. A case report with a review of the literature.

Chronic myelogenous leukemia (CML) is a pluripotent stem cell malignancy with an incidence of 1.3 per 100,000. Occasionally this uncommon disease occurs concomitantly with other neoplasia including various lymphoproliferative disorders. Its association with solid tumors, especially in young people, is decidedly rare. We report the simultaneous occurrence of CML and signet-ringed adenocarcinoma of the rectum in a 20-year-old male. A review of the literature pertinent to this topic will be briefly discussed, emphasizing characteristics of rectal carcinomas in younger age-groups as well as the unexpected association of CML with solid tumors.

Adult↗
PubMed1994

Acute hypersplenism and thrombocytopenia: a new presentation of disseminated mycobacterial infection in patients with acquired immunodeficiency syndrome.

We describe 2 patients with acquired immunodeficiency syndrome who presented with acute or subacute splenomegaly and thrombocytopenia secondary to disseminated Mycobacterium avium complex (MAC). The patients were treated for immune thrombocytopenic purpura without success. Thrombocytopenia may be a prominent feature of MAC. Our experience suggests that disseminated MAC may present with acute splenomegaly and thrombocytopenia in these patients and that a high index of suspicion for disseminated tuberculosis is indispensable in order to avoid delay in diagnosis and treatment in patients presenting with rapidly progressive splenomegaly and thrombocytopenia.

AIDS-Related Opportunistic Infections↗