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Biomedical subjects

N Fernandez

Publications and source records attributed to N Fernandez.

101 records · Page 6Linked to original sources
PubMed1977

Pathologic findings in human scabies.

The histologic findings in the papular, vesicular, nodular, and Norwegian variant of scabies have in common a superficial and deep perivascular mixed inflammatory cell infiltrate of lymphocytes, histiocytes, and numerous eosinophils. A spongiotic vesicle occurs in the papulovesicular type, a dense cellular infiltrate in the nodular type, and a hyperkeratotic psoriasiform dermatitis in the Norwegian type. Eggs, larvae, and adult mites are abundant in the cornified layer of Norwegian scabies, are practically never found in biopsy specimens from lesions of nodular scabies, and are discovered only episodically in papulovesicular lesions.

Blood Cells↗
PubMedDate not supplied

Molecular profiles of the cell membrane bound and cytoplasmic forms of the human MHC class-II associated invariant polypeptides.

Several sub-types of histocompatibility class-II molecules are known to exist, including DR, DQ and DP, each subset organized in alpha and beta heterodimers. These molecules play a central role in immunorecognition via direct noncovalent binding of degraded nonself immunogenic peptides followed by ligand-interaction with T cells. In the cytoplasm the class-II alpha and beta chains associate, in addition with a third backbone molecule known as the invariant chain. In this study we show that all class-II subsets associate with the invariant chain probably from the same pool and that a subset of invariant chain is expressed as a cell surface subunit. This sub-unit, whose function is still unknown, was detected by flow-cytometry and by two-dimensional gel analysis followed by antibody-mediated immunoprecipitations.

Antibodies, Monoclonal↗
PubMedDate not supplied

Total homocysteine levels relation with chronic complications of diabetes, body composition, and other cardiovascular risk factors in a population of patients with diabetes mellitus type 2.

OBJECTIVE: The significance of hyperhomocysteinemia in type 2 diabetes is further complicated by the multiple ways of considering impaired renal function and vitamin status. The aim of our study was to analyze the relationship between total homocysteine (tHcy) in a population of type 2 diabetic patients and chronic complications. We also analyzed the relationship between tHcy and the body composition of these patients and other cardiovascular risk factors. DESIGN: In a cross-sectional study, a total of 155 patients with diabetes mellitus attending in our diabetes service (90 females/65 males) were enrolled in a consecutive way. MATERIAL AND METHODS: All enrolled patients underwent the following examinations: (i) biochemical cardiovascular risk factors including total cholesterol, triglyceride, lipoprotein (a), low-density lipoprotein (LDL-cholesterol), high-density lipoprotein (HDL-cholesterol), glucose, HbA(1c), fibrinogen, homocysteine, vitamin B12, folate, and microalbuminuria; and (ii) fat mass assessed by body mass index, weight, percentage of fat mass, and tricipital skinfold. RESULTS: Patients were divided in two groups (Group I: tHcy> or =15 micromol/l; Group II: tHcy<15 micromol/l). Smoking habit was similar in both groups. A prevalence of cerebrovascular accident was present in 3.3% in the total group. This prevalence was not different in both groups (7.4% vs. 2.3%; ns) (OR 3.3; 95% CI 0.49-19.68). The prevalence of coronary heart disease in the total group was 5.8% without statistical differences between groups (3.5% vs. 6.3%; ns) (OR 0.57; 95% CI 0.065-4.53). Concerning macrovascular complications, only peripheral vascular disease prevalence was higher in Group I (16% vs. 3.1%; P<0.05; OR 5.33; 95% CI 1.18-21.5). A prevalence of nephropathy was higher in Group I (93.3% vs. 12.8%; P<0.05; OR 7.15; 95% CI 2.9-17.9). No statistical differences were detected in prevalence of retinopathy (global group 41.9%) (42.5% vs. 40.9%; ns) (OR 1.75; 95% CI 0.78-3.9). Also, peripheral neuropathy was similar in both groups (7.1% vs. 6.5%; ns) (OR 1.1; 95% CI 0.15-8.2). No correlation was detected among homocysteine and anthropometric parameters (body mass index, weight, percentage of fat mass, fat mass, and tricipital skinfold). Elevated levels of fibrinogen, lipoprotein (a), microalbuminuria, and blood pressure were detected in Group I. CONCLUSION: The present study shows that elevation of plasma tHcy levels in type 2 diabetic patients is associated with a higher prevalence of peripheral arteriopathy and nephropathy. Our data suggest that hyperhomocysteinemia is not associated with fat mass but it is associated with high levels of fibrinogen, lipoprotein (a), microalbuminuria, and blood pressure levels.

Aged↗
PubMedDate not supplied

Porphyrin, chlorin, and bacteriochlorin isothiocyanates: useful reagents for the synthesis of photoactive bioconjugates.

A novel method for conjugating porphyrins and related molecules to proteins has been developed. The method, which involves synthesizing porphyrins, chlorins, and bacteriochlorins bearing a single amine-reactive isothiocyanate group represents a facile system for protein labeling with these photoactive species. Problems associated with the noncovalent binding of porphyrins to proteins are highlighted, and a method for purifying conjugates to yield exclusively covalently bound porphyrin protein species is demonstrated. Biological activity of porphyrin-bovine serum albumin conjugates formed and purified by these methods is demonstrated using laser scanning confocal microscopy.

Animals↗
PubMedDate not supplied

A critical review of the role of the major histocompatibility complex in fertilization, preimplantation development and feto-maternal interactions.

From conception to old age, the major histocompatibility complex (MHC) is at the centre of immune responses that aid survival, fitness and adaptation of mammalian species to the environment. Its main function is that of controlling adaptive immunity, particularly T-cell-mediated immunity towards pathogens. In several species, including humans, the MHC is also able to elicit T-cell-mediated immune responses to allogeneic MHC antigens (non-self MHC antigens expressed by another individual from the same species). Although this phenomenon was originally identified in mice by the somewhat unnatural means of tissue transplantation, it was soon realized that it may also play an important role in the natural state, since the mammalian fetus in the maternal uterus is semi-allogeneic, due to the presence of MHC genes inherited from the father. Thus, during normal pregnancy the maternal immune system undergoes changes that lead to tolerance of the fetus. The MHC can play a dual role in the reproduction process: firstly influencing mating choice in some species, affecting the mother-father MHC matching; and secondly influencing the development of the fertilized ovum during the preimplantation period. In this review we examine the role of the MHC at three distinct levels: (i) MHC expression in gametes and its role in fertilization; (ii) MHC expression in placental tissue; and (iii) MHC expression in embryonic tissue. We suggest that the MHC plays a pleiotropic role, both in fitness (survival and reproductive success) and in development, thereby ensuring the survival of the species in future generations.

Animals↗
PubMedDate not supplied

The expression of murine Qa region gene product(s) in L cell transformants.

The cosmid H3.5, containing genes mapping to the murine H-2 Qa region, was used to transfect L cells by the calcium phosphate co-precipitation method. The resultant transfected cells expressed a Qa-like determinant as detected by an immune serum raised against the transfectant cells and Qa specific monoclonal antibodies. Two-dimensional gel analysis revealed the expression of a class I-like heavy chain with a similar molecular mass to the Qa2 antigens of the positive strain B10 and B10.A but with a different isoelectric point. The cosmid H3.5 spans 40 kb of DNA and contains at least one complete Qa region gene which encodes the Qa-like determinant detected in this study.

Animals↗
PubMedDate not supplied

[Seroprevalence of T. cruzi infection in 6- and 12- year-old school children from three Uruguayan endemic departments].

The last national survey on seroprevalence of T. cruzi human infection in Uruguay, showed a 3.4% in adults from endemic areas. Since 1983, antivectorial actions of the control program have been carried out continually. In consequence, household infestation by Triatoma infestan, the main vector of T. cruzi in Uruguay, decreased in all endemic areas and was completely eliminated in some of them. The objectives of the present work are to evaluate the new seroepidemiological situation. A representative sampling of rural and urban population was undertaken, to include six and twelve year-old school children from three departments: Artigas, Rivera and Tacuarembo. The whole sample included 4,722 school children, evaluated by the indirect immunofluorescence (IFI) test for Chagaś disease. The seroprevalence of T. cruzi infection in the six year-old group was 0.3% in Artigas, 0.6% in Rivera and 1.0% in Tacuarembo. The seropositive children with seropositive mothers support the possible congenital transmission.

Animals↗
PubMedDate not supplied

Does preventive vaccination with engineered tumor cells work in cancer-prone transgenic mice?

The use of genetically modified tumor cells as vaccines has been successful in numerous animal models of grafted syngenic tumors and has provided the groundwork for many clinical trials of gene therapy in cancer patients. To investigate the real efficacy of ex vivo gene therapy-based vaccines, we used transgenic mice that express the SV40 large T and small t antigens under the control of hepatic antithrombin III (ASV-B)-regulatory sequences. These mice systematically develop hepatocarcinoma. Hepatoma cells, derived from ASV-B transgenic mice, were gene-transduced to express either interleukin-2, interleukin-4, the granulocyte-macrophage colony-stimulating factor, or the T-cell costimulatory molecule B7.1. First, we demonstrated the vaccine potential of engineered hepatoma cells by immunizing nontransgenic mice with these cells, which prevented the growth of subsequent grafted nontransduced hepatoma cells. However, vaccination of pretumoral transgenic animals with various combinations of engineered hepatoma cells failed to inhibit hepatoma onset and progression. Rather, tumor development in ASV-B mice appears to be dependent on the immune system, since neonatal induction of immunotolerance to tumor in ASV-B mice cells was associated with a moderate, but significant, acceleration of tumor development. These results seriously call into question the efficacy of this strategy of active vaccinotherapy against natural tumors.

Animals↗