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Biomedical subjects

D Levy

Publications and source records attributed to D Levy.

At least 397 records · Page 22Linked to original sources
PubMed1983

Does hyperimmunoglobulinemia-E protect tropical populations from allergic disease?

The Waorani Indians of eastern Ecuador have the highest blood concentration of IgE reported in a human population. Evidence obtained by medical history, physical examination, and immediate hypersensitivity skin tests suggests that pollen allergy and other atopic diseases are rare among the Waorani. A similar association between parasite-induced hyperimmunoglobulinemia-E and a low prevalence of conventional atopic disease has been reported in numerous other tropical populations. Saturation of mast cell IgE receptors with antibodies directed to the parasite and/or other antigens and competitive inhibition of passive binding of pollen allergen-specific IgE is one hypothetical cause of this association. We have tested this interesting conjecture by passively sensitizing the skin of Waorani Indians with serum containing pollen allergen-specific IgE antibodies. Waorani Indians with hyperimmunoglobulinemia-E can be adoptively sensitized with human ragweed or rye grass hyperimmune IgE antisera. This suggests that the cutaneous mast cells of healthy Waorani have active IgE receptors. The high circulating plasma concentrations of IgE in the Waorani do not prevent adoptive cutaneous sensitization with pollen-specific IgE antibodies.

Ecuador↗
PubMed1983

New evidence on controlling alcohol use through price.

A problem in earlier studies of the demand for beer, wine and distilled spirits was determining the effect on one category of alcoholic beverage of price changes in other categories. The present study estimates the demand for all alcoholic beverages, finding a stable relationship over a 40-year period. Policy implications are also discussed.

Alcohol Drinking↗
PubMed1982

Analysis of the transport system for inorganic anions in normal and transformed hepatocytes.

The transport system for inorganic anions has been investigated in hepatocytes and hepatoma tissue culture cells. Sulfate transport in hepatocytes is temperature sensitive and occurs against an electrochemical gradient. Uptake was shown to occur by a sodium-dependent and a sodium-independent route with Km values of 2.3 and 33 mM and Vmax values of 2.1 and 10 nmol/mg of protein/min, respectively. An analysis of the sodium dependency indicates a Hill coefficient of 1.05 suggesting an equimolar stoichiometry for sodium and sulfate transport. The transport of sulfate was decreased by metabolic and sodium transport inhibitors. Bicarbonate was shown to effect the transport of sulfate, where uptake was accelerated by intracellular bicarbonate and competitively inhibited by extracellular bicarbonate. In addition, sulfate efflux was stimulated by extracellular bicarbonate. These results suggested that bicarbonate is a substrate for the sulfate transport system and can accelerate uptake and efflux by an anion exchange mechanism. Inhibition of bicarbonate uptake by extracellular sulfate and by the anion transport inhibitor 4,4'-diisothiocyano-2,2'-stilbene disulfonate demonstrates that bicarbonate does not enter the cell exclusively by CO2 diffusion but can be transported in part as an anionic species. These results are consistent with its role in the sulfate-bicarbonate exchange system. This inorganic anion transport system was shown to be inhibited by approximately 80% in hepatoma tissue culture cells where altered sodium dependency, Km, and Vmax values reflect possible alterations in the structure and/or membrane content of the carrier.

Animals↗
PubMed1982

Penicillin-resistant Streptococcus constellatus as a cause of endocarditis.

Endocarditis in a 2-year-old child was caused by a penicillin-resistant Streptococcus constellatus. Viridans streptococci in general and those associated with endocarditis in particular are usually believed to be penicillin sensitive. Although the patient did not receive prophylactic antibiotics, the child had recently been treated with an oral penicillin. Penicillin-resistant viridans streptococci are usually sensitive to the synergistic effects of penicillin and an aminoglycoside, but this organism was not. Clindamycin was ultimately shown to demonstrate admirable bactericidal activity against this patient's S constellatus.

Clindamycin↗
PubMed1982

Late-onset steroid 21-hydroxylase deficiency: a variant of classical congenital adrenal hyperplasia.

Hormonal studies and human leukocyte antigen (HLA) genotyping were performed in 5 males and 13 females who were demonstrated to have 21-hydroxylase deficiency. The enzymatic deficiency of steroidogenesis was detected by family studies of 10 females who presented with varying symptoms of androgen excess. The 10 index cases had normal genitalia at birth, but virilized to varying degrees postnatally. The additional 8 affected family members had not sought medical care, but some were found to have signs of virilization on physical examination, while others were normal. Thus both late-onset (symptomatic) and cryptic asymptomatic) 21-hydroxylase deficiency occurred in the same pedigree. The hormonal and genetic linkage studies indicate that the late-onset (symptomatic) form of 21-hydroxylase deficiency, like the cryptic (asymptomatic) and classical forms of 21-hydroxylase deficiency, is transmitted by an autosomal recessive gene which is linked to HLA-B. Furthermore, the classical form of 21-hydroxylase deficiency associated with prenatal virilization is transmitted by an allelic variant for steroid 21-hydroxylase different from that of the nonclassical forms, late-onset (symptomatic) and cryptic (asymptomatic) 21-hydroxylase deficiency. Although these latter 2 disorders have different clinical manifestations, they demonstrate a similar degree of steroid 21-hydroxylase deficiency that is less severe than that observed in classical 21-hydroxylase deficiency. The hormonal and genetic linkage data indicate that cryptic (asymptomatic) and late-onset (symptomatic) 21-hydroxylase deficiency result from the same allelic variant at the steroid 21-hydroxylase locus. A glossary of terms is presented to describe the various allelic forms of 21-hydroxylase deficiency with consistency.

Adolescent↗
PubMed1982

[Human pentastomiasis in Abidjan. A report on 29 cases].

The authors report 29 cases of human pentastomida detected radiologically in the medical thoracic service over 10 years and a fatal case occurring in the paediatric clinic. After a parasitological review of the life cycle and localisation of the pentastomida in man, the epidemiology clinical picture and typical radiological appearance of thoracic and abdominal calcification are discussed. They are always detected by chance and it is the case history which establishes the link between the eating of poorly cooked snakes or their handling. Finally a case is mentioned (which is currently unique in the literature) of a massive fatal septicaemia in a five years old child caused by Armillifer grandis, which poses the problem of the diagnostic difficulty in current clinical practice of this infestation. Since 1973 the disorder can be diagnosed immunologically thanks to the Marseilles school, but it is difficult to achieve in practice. It would only allow an estimation of the frequency of this infestation and to define the clinical features possible.

Adult↗
PubMed1981

Typing of murine cell-surface antigens by cellular radioimmunoassay.

A cellular radioimmunoassay utilizing 125I-labelled Protein A was used for detecting antigen-antibody complexes on glutaraldehyde fixed cells attached to microtiter plates. This method is rapid, sensitive and specific for revealing H-2 private and public specificities as well as Ia and Lyt antigens. As plates may be kept for months, several reactivities can be tested in one step on a large panel rendering a regular supply of animals unnecessary.

Animals↗
PubMed1981

Permanent tetraplegia as a consequence of tetanus neonatorum. Evidence for widespread lower motor neuron damage.

It is generally believed that no permanent neurological damage is found among survivors of tetanus neonatorum. Newborns dying shortly after the onset of tetanus also lack significant neurological abnormalities. In adults a variety of neuromuscular lesions have been reported; however, a uniform pathological picture is absent. We report a case of a newborn with severe tetanus in whom striking evidence of anterior horn neuronal damage was documented, causing permanent nonprogressive tetraplegia. We suggest that the mechanism responsible for this lesion involves the retrograde axoplasmic flow of tetanus toxin reaching the spinal cord via nerve endings in the infected umbilical cord stump.

Atrophy↗
PubMed1981

The somatic replication of DNA methylation.

We have tested the hypothesis that DNA methylation patterns are replicated in the somatic cells of vertebrates. Using M-Hpa II, the modification enzyme from Haemophilus parainfluenzae which methylates the internal cytosine residues in the sequence 5'CCGG 3' GGCC, we methylated bacteriophage phi X174 RF DNA and the cloned chicken thymidine kinase (tk) gene in vitro and then introduced these DNAs and unmethylated controls into tk- cultured mouse cells by DNA-mediated transformation. Twenty-five cell generations later, the state of methylation of transferred DNA was examined by restriction endonuclease analysis and blot hybridization. We conclude that methylation at Hpa II sites is replicated by these cultured cells but not with 100% fidelity. We have also noted that methylation of the cloned chicken tk gene decreases its apparent transformation efficiency relative to unmethylated molecules.

Animals↗
PubMed1980

The role of adjuvant therapy in Stage I ovarian cancer.

Women with Stage I epithelial carcinoma of the ovary were initially treated by an extirpative operation and were subsequently randomized to either no further treatment, radiotherapy, or chemotherapy. Only two patients (6%) treated with chemotherapy developed recurrence, compared to five (17%) and seven (30%) patients in the no-treatment and radiotherapy regimens, respectively (P < 0.05). All patients, with the possible exception of those with Stage IA(1)g1, appeared to benefit from adjuvant chemotherapy compared to no treatment or radiotherapy.

Adenocarcinoma↗
PubMed1980

Spontaneous immune response of bovine leukemia-virus-infected cattle against five different viral proteins.

The sera from cattle exposed to bovine leukemia virus (BLV) have been studied by the radioimmunoprecipitation assay (RIPA) of disrupted virus proteins. All sera of animals with the adult form of lymphosarcoma precipitated four different viral proteins: gp51, gp35, p24 and p12. In contrast, the sera of five animals with the juvenile or thymic forms of bovine lymphosarcoma were completely devoid of precipitating activity against BLV proteins, confirming the absence of relationship between these rare malignant diseases and BLV infection. The sera of non-leukemic cattle from areas of high risk of exposure to BLV were either negative or positive to a lower degree than the sera of lymphosarcomatous cows. When positive they precipitated gp51, p24 and p12. Only one serum precipitated gp35. The difference was probably quantitative, the sera of leukemic animals having higher levels of precipitating activity against all the viral proteins. The anti-gp51 reactivity was in most cases the strongest, whatever the origin of the serum. In the rare sera which were positive in the classical anti-gp51 radioimmunoassay (RIA) but negative in the anti-p24 RIA, an anti-p24 activity was, however, detected by the RIPA. These results suggest that BLV-infected cows regularly produce antibodies reacting with four different viral proteins including minor viral components. In three cases with no other special features a low level of activity was detected against a fifth component: p15. There was no apparent correlation, however, between the antibody response and an hypothetical protection against BLV-induced disease.

Absorption↗