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Biomedical subjects

M Cabrera

Publications and source records attributed to M Cabrera.

50 records · Page 3Linked to original sources
PubMed1988

T-cell subpopulations, expression of interleukin-2 receptor, and production of interleukin-2 and gamma interferon in human American cutaneous leishmaniasis.

Leukocyte subpopulations, the expression of the interleukin-2 (IL-2) receptor, and the production of IL-2 and gamma interferon (IFN-gamma) were studied in the peripheral blood mononuclear cells of American cutaneous leishmaniasis patients that had been stimulated in vitro with either leishmanial antigen or mitogen (phytohemagglutinin M). The 75 patients examined were classified as having either the localized (LCL; 66 patients), mucocutaneous (MCL; 5 patients), or the rare diffuse (DCL; 4 patients) form of the disease. Patients with DCL, who are characterized by their defective cell-mediated immune response to leishmanial antigen, failed to express the IL-2 receptor and did not produce IFN-gamma when exposed to the antigen but did so when stimulated by phytohemagglutinin M. Both LCL and MCL patients showed strong proliferative responses to leishmanial antigen; these were by far the greatest in MCL patients. Both groups had significantly increased IL-2 receptor expression and IFN-gamma production after exposure to either antigen or mitogen, and these were highest in the MCL patients. Concerning the leukocyte subpopulations evaluated (CD2, CD4, CD8, CD20, MO2), the most significant findings were a decrease of both CD4+ cells and the CD4/CD8 ratio in MCL patients compared with the other groups. Considering IL-2 production, in response to phytohemagglutinin M both MCL and LCL patients showed amounts of IL-2 comparable to those of the controls. Our results help explain the anergy of T cells from DCL patients to leishmanial antigen, which could lead to a defective production of IFN-gamma and possibly contribute to their incapacity to kill the Leishmania parasite. Concerning MCL patients, the significantly increased expression of IL-2 receptor, decreased expression of the CD4 (helper-inducer of suppression) phenotype, and elevated IFV-gamma production might partially explains the state of hypersensitivity and mucosal damage exhibited by these patients.

Adult↗
PubMed1984

Calorimetric validation of the doubly-labelled water method for determination of energy expenditure in man.

The turnover rates of water and carbon dioxide have been estimated at frequent intervals after a single dose of 2H2 18O had been given to an adult monitored continuously in a whole body calorimeter for 5 d. The integrated CO2 production rate for 5 d, estimated from the differential rates of 2H and 18O excretion in urine, was within 2 per cent of the actual CO2 output, based on an improved method of calculation. Changes occurred in the abundance of 2H and 18O in response to activity, so that the timing of samples was important. It was found better to compute the production rate of CO2 from multiple samples rather than from measurements at only two points of time. The proportion of total water lost by evaporation proved to be less than previously assumed. Direct validation of the technique requires calorimetric studies of 2 to 3 weeks duration, in either animals or human subjects. The potential value of this method for measurement of energy expenditure in man is such that exacting tests of its accuracy and precision are needed before it is adopted for general use in metabolic and epidemiological studies.

Adult↗
PubMed1983

Growth of Propionibacterium acnes strains on semisynthetic medium; antigenic polysaccharide production.

A semisynthetic medium, containing yeast extract as the only non defined component and glucose, glycerol, Tween 80 and mineral salts, has been developed to grow the strains of Propionibacterium acnes Beck 2037, Gerrath 2038 and Vogel 2039, at a rate comparable to that of complex media. An average of 10(12) cells per 1 (equivalent to approximately 1.5 g/l dry weight) was usually achieved. These yields are appropriated for biochemical and immunological studies, e.g. cell wall preparation, polysaccharides isolation, etc. In this work, some properties of the cell walls (sugar and amino acid composition) and the antigenic polysaccharides (neutral and amino sugar components) are described.

Amino Acids↗
PubMed1968

Gangliosides in subacute sclerosing leukoencephalitis: isolation and fatty acid composition of nine fractions.

Gangliosides from brain of an 8 yr old boy with subacute sclerosing leukoencephalitis have been studied in terms of pattern and structure. Thin-layer chromatography showed that both gray and white matter have a highly abnormal pattern, with elevation of the relative proportion of four gangliosides corresponding to minor species in normal brain. The total level of lipid-bound sialic acid, however, was not increased, which indicated a compensating loss of other gangliosides. Two of the proliferating species were monosialogangliosides (G(5) and G(6)) (Korey nomenclature), and two were disialo types (G(2A) and G(3A)). Studies of their carbohydrate structures are described. Nine ganglioside fractions were isolated by preparative TLC in combination with column chromatography, and the fatty acid compositions were determined. Seven contained stearate as the major component, while two (G(3A) and G(6)) had relatively large proportions of oleate and palmitate. Five of the fractions contained two fatty acids of long chain-length and unknown structure.

Brain Chemistry↗
PubMedDate not supplied

First case of natural infection in pigs. Review of Trypanosoma cruzi reservoirs in Mexico.

An epidemiological research project was performed in the State of Morelos including collection of samples for blood smears and culture, serological tests, and xenodiagnoses from a total of 76 domestic and peridomestic mammals. Two strains of Trypanosoma cruzi were isolated by haemocultures; one from a pig (Sus scrofa), the first case of natural infection reported in Mexico, and the other from a dog (Canis familiaris). This study summarizes current information in Mexico concerning confirmed reservoirs of T. cruzi.

Animals↗
PubMedDate not supplied

Pseudo-allergic reactions to corticosteroids: diagnosis and alternatives.

Two patients treated with parenteral paramethasone (Triniol) and dexamethasone (Sedionbel) are described. A few minutes after administration of the drugs, they presented urticaria (patients 1 and 2) and conjunctivitis (patient 1). The purpose of our study was to determine the cause of the patients' reactions, the immunological mechanisms involved and whether these patients would be able to tolerate any kind of corticoid. Clinical examinations and skin, oral and parenteral challenges with different corticosteroids and ELISA tests were performed. In the two patients, skin and ELISA tests with paramethasone were negative, as was the prick test with each of its excipients. A single-blind parenteral challenge with Triniol was positive in both patients after the administration of 1 ml of the drug, and negative with its excipients. We also carried out oral and parenteral challenges with other corticosteroids and found intolerance to some of them. These results suggest that paramethasone caused pseudoallergic reactions in our patients. Corticosteroids different from paramethasone also produced hypersensitivity reactions in these patients; however, a few of them were tolerated. The basic mechanisms of those reactions are not yet fully understood. To our knowledge, this is the first report of a pseudo-allergy caused by paramethasone.

Adult↗
PubMedDate not supplied

Genitourinary tuberculosis: the importance of early diagnosis and management. Case presentation.

Genitourinary tuberculosis is the second most common form of extrathoracic tuberculosis. The most common signs are persistent sterile pyuria in up to 90% of patients, irritative voiding symptoms and painless hematuria in up to 80% of the patients. In Puerto Rico the incidence of tuberculosis is rising, being 9.2 per 100000 population in 1992. A.I.D.S. has had a steady rise since 1983. With the rise in the incidence of both diseases and with the influx immigrants from countries were tuberculosis is endemic we should expect a rise in the number of cases of genitourinary tuberculosis. Chemotherapy is the mainstay of treatment. Surgery is performed less often. Early recognition and management is important to avoid irreversible damage to the genitourinary tract. The cases of a 43 y/o man and a 30 y/o male with A.I.D.S. are discussed.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Severe allergic conjunctivitis and chemosis caused by disodium cromoglycate.

A 63-year-old man with chronic, nonallergic rhinoconjunctivitis presented immediate adverse reactions, such as intense itching, burning, redness and severe swelling of both conjunctivae after using disodium cromoglycate eye drops. Skin prick tests and conjunctival provocation tests were positive with pure disodium cromoglycate. Circulating IgE-specific antibodies to disodium cromoglycate in serum were demonstrated by RAST. We suggest that the acute ocular reaction was caused by disodium cromoglycate and that the underlying mechanism was probably an IgE-mediated immunological reaction.

Conjunctivitis, Allergic↗