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Biomedical subjects

J Vidal

Publications and source records attributed to J Vidal.

At least 127 records · Page 7Linked to original sources
PubMed1995

Lack of relationship between human immunodeficiency virus infection and systemic lupus erythematosus.

The objective of this work was to determine whether HIV-1 and HIV-2 could be involved in the pathogenesis of systemic lupus erythematosus (SLE). Seventy-five consecutive Caucasian patients with SLE presenting at one institution over a 2-year period were studied. Serum samples were surveyed for anti-HIV-1 antibodies by a commercial ELISA coated with HIV-1-p24. For confirmation, conventional immunoblots were performed with the following antigens: HIV-1-gp41, p31, p24 and p17 (recombinant) and HIV-2-gp36 (synthetic peptide). Additionally, Western blots with HIV-1-gp160, gp120, gp41, p65, p51, p24 and p18 bands were applied. Seventeen (23%) patients exhibited reactivity with HIV-1-p24 in the ELISA, but in the immunoblots and Western blots these sera samples were negative. Patients with SLE may exhibit a reactivity with HIV-1-p24 in the ELISA for HIV infection screening but not in the confirmatory blots. This false-positive reactivity is probably due to molecular mimicry between autoantigens and retroviruses or a contaminant or artefacts in the antigen preparation procedure.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Relationship between Epstein-Barr virus and lymphoproliferative syndromes in patients without immunodeficiency].

PURPOSE: The relationship between Epstein-Barr virus (EBV) and infectious mononucleosis, pharyngeal carcinoma and Burkitt's lymphoma is well known. Further relationship seems to exist between EBV and the lymphoproliferative syndromes appearing in immunodeficient subjects. The present work is aimed to study the possible relationship between the virus and the lymphoproliferative syndromes presented by people without any apparent immunodeficiency. PATIENTS AND METHODS: The presence of antibodies against different antigens of the virus was analysed. Antibodies against the viral capsid antigen were studied along with those against the early antigen and the viral core antigen in 55 patients with lymphoproliferative syndromes, of whom 38 had non-Hodgkin's lymphoma and 17 had acute lymphoblastic leukaemia, and none of them had immunodeficiency. RESULTS: Significantly higher geometric means of the titres against capsid antigen and of the prevalence of antibodies against early antigen were seen in the patients with non-Hodgkin's lymphoma with respect to the control group. On the contrary, patients with acute lymphoblastic leukaemia showed lower immunologic response than the control group, although the difference was not significant for any of the antibodies under study. CONCLUSIONS: The higher immunologic response against EBV and its reactivation in non-Hodgkin's lymphoma would suggest that such agent could play a role favouring the onset of the disease, if not as a direct aetiological factor.

Adolescent↗
PubMed1994

[Seroepidemiology of hepatitis C virus infection in pregnant women in Catalonia].

BACKGROUND: The aim of this study was to investigate the prevalence of hepatitis C virus (HCV) infection in a population of pregnant women in Catalonia and the sociodemographic variables and risk factors associated to this prevalence. METHODS: A representative sample of the pregnant women in Catalonia (n = 4,551) randomly selected by clusters (hospitals with maternity clinics) was studied. Detection of antiHCV antibodies was performed by the third generation ELISA test. Reactive cases were confirmed with RIBA 3 and MATRIX. RESULTS: The prevalence of antiHCV was found to be 1% and was not significantly associated with any of the sociodemographic variables studied (age, social and cultural level, origin and residence). A history of blood transfusion, intravenous drug consumption and hepatitis in the sexual partner were the only risk factors associated with the prevalence of infection found on univariate analysis although these were only present in 47% of the antiHCV positive cases detected. The association between the positivity of antiHCV and the history of hepatitis in the partner was lost on stratification of the cases according to the possible existence of history of drug addiction. CONCLUSIONS: A high proportion of young asymptomatic people (1%) were found to have hepatitis C virus infection with the possible mode of infection not being detected in approximately half of these subjects. In the other half of these cases the infection was found to have been acquired by an intravenous mechanism: blood transfusion or drug use.

Adult↗
PubMed1994

[Infection by the human immunodeficiency virus type 1 in the population of prisoners of Catalonia].

BACKGROUND: The prison population represents a high risk group for the human immunodeficiency virus type 1 infection. The present study was carried out to know the prevalence of infection in this collective in three penitentiary centers in Catalonia. METHODS: All the subjects who were in or who were admitted to the three penitentiaries for men from October 1987 to April 1988 were included in the study (n = 1,579). Demographic risk factor and penitentiary variables were obtained. The determination of anti-HIV-1 antibodies was performed by enzymoimmunoanalysis (Dupont HIV ELISA). RESULTS: The global prevalence of HIV-1 infection was of 40.6%. Significant statistical differences were found among intravenous drug users (IVDU) and non IVDU (chi 2 = 376.8, p < 0.0001, OR = 9.6, CI 95% = 7.5 - 12.3) and between habitual and sporadic users (chi 2 = 23.9, p < 0.0001, OR = 3.0, CI 95% = 1.9 x 4.7). CONCLUSIONS: The penitentiary population in Catalonia is a collective with a high prevalence of infection by the human immunodeficiency virus type 1, with intravenous drug use being the fundamental factor associated to this prevalence.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The effect of pH on the covalent and metabolic control of C4 phosphoenolpyruvate carboxylase from Sorghum leaf.

The influence of pH on the in vitro activity and regulatory properties of Sorghum leaf C4 phosphoenolpyruvate carboxylase (PEPC) was investigated with respect to the phosphorylation status of the enzyme. In vitro protein phosphorylation was achieved using the catalytic subunit of a cAMP-dependent protein kinase (PKA) and a recombinant, immunopurified PEPC (0.9 mol of covalent Pi/mol PEPC subunit). Between pH 6.8 and 8, velocity and IC50 for L-malate increased for both the nonphosphorylated and the phosphorylated forms. With respect to the nonphosphorylated PEPC, the phospho-PEPC always gave high values for these kinetic parameters at the pH range investigated, especially between pH 7 and 7.3. The phosphorylation-induced stimulation of PEPC activity was four- to fivefold at pH 7.1 and approximately twofold at pH 7.3. The IC50 for L-malate showed a two- to threefold increase at pH 7.3, but varied less at pH 7.1 upon PEPC phosphorylation. Thus, phosphorylation of PEPC caused a predominant V effect or a mixed (V/IC50) effect at pH 7.1 or 7.3, respectively. This was also observed with the enzyme from desalted crude protein extracts from dark or light-adapted Sorghum leaves and leaf-derived mesophyll protoplasts illuminated in the presence of methylamine, a compound known to increase cytosolic pH (pHc). At pH 7.3, desensitization to L-malate of phospho-PEPC was due to an enhanced ability of PEP to compete with the inhibitor. The positive effector glucose-6P acted similarly to phosphorylation; however, a combination of both factors (glucose-6P and phosphorylation) led to a much larger increase in the IC50 for L-malate than that observed by a single factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucosephosphates↗
PubMed1994

Congenital panhypopituitarism of late onset.

A 29-year-old male was diagnosed congenital panhypopituitarism due to pituitary hypoplasia, absence of pituitary stalk and ectopic neurohypophysis. This report, together with bibliographic review, may induce to reconsidering isolated GH failures, partial hypopituitarisms and panhypopituitarisms which have up to now been interpreted as idiopathic. The availability of new image techniques has allowed a better definition of the anatomic substrate of these alterations, and more subtle hormonal studies have pointed out, in some cases, their possible hypothalamic origin. On this basis, some of these cases may be interpreted as presenting the same alteration as those described in necropsy of newborns dead due to severe panhypopituitarism. Therefore, a unique clinical picture with various degrees of severity may be postulated.

Adult↗
PubMed1994

Diabetes mellitus in patients with liver cirrhosis.

In spite of the high prevalence of diabetes mellitus (DM) in patients with liver cirrhosis (LC) few studies have focused on the clinical implications of this association. We investigated the clinical and pancreatic-endocrine features of 34 patients who developed DM after LC (Group I). Results were compared with 34 carefully matched patients with only Type II DM (Group II). A standard meal test was performed in 26 patients with normal renal function from each group to assess beta-cell function. Group I patients, less frequently had retinopathy (14.7% vs. 45.5%, P < 0.05) and a family history of diabetes (23.5% vs. 58.8%, P < 0.01). Group I patients also showed signs of enhanced insulin resistance, reflected by higher insulin dose requirements in insulin-treated patients (0.87 +/- 0.10 vs. 0.62 +/- 0.05 IU/kg/day, P < 0.01) and increased basal C-peptide values (0.88 +/- 0.06 vs. 0.68 +/- 0.07 pmol/l, P < 0.05, respectively) than those in Group II. These results suggest that several clinical features, probably related to the hepatopathy, define DM occurring in patients with LC.

Blood Glucose↗
PubMed1994

Association of the antibody response to hemocyanin with behavior in mice bred for high or low antibody responsiveness.

Researchers attempted to find a genetic correlation between the antibody response and some behaviors by comparing the behavioral profile of good antibody-producing mice (Biozzi's H mice) with that of bad antibody producers (Biozzi's L mice). The behavioral tests used were 2 open fields, a light-darkness test, and reaction to capture; the antigen was keyhole limpet hemocyanin, and blood levels of immunoglobulin (Classes IgM and IgG) antibodies to hemocyanin were measured by diffusion-in-gel-enzyme-linked immunosorbent assay. H and L mice differed in the magnitude of the antibody response (H > L), in reaction to capture (L > H), and in rearing in 1 of the open fields (L > H). Yet the level of IgM or IgG antibodies was uncorrelated with those behaviors in the (H x L) F2 hybrids and in outbred CD1 mice. Thus, the behavioral differences between H and L mice are not due to the antibody response genes but to other genes fixed during selection for antibody responsiveness.

Animals↗
PubMed1994

Behavior and the antibody response as differential traits in three murine inbred strains (DBA/2, BALB/c, C57BL/6).

The goal of this research was to find out whether an antibody response is consistently associated with any particular behavior across three murine strains (C57BL/6, BALB/c, and DBA/2). The mice took the following behavioral tests: two open fields, a hole board, and a light-darkness test; afterward, they were immunized with rat erythrocytes, and serum levels of IgM and IgG antibodies were measured 5 and 15 days postimmunization. Nonparametric Kruskal-Wallis and Mann-Whitney tests were used to reveal the set of variables that differentiated the three strains or pairs of the strains. The set of (behavioral and immune) variables that distinguished any two strains or all three strains depended on the particular combination of strains compared.

Animals↗
PubMed1994

Crystal structure analysis of a beta-turn mimic in hydrazino peptides.

The crystal structures of four hydrazino peptides (Piv-Pro-h(N alpha-Bzl)Gly-NHiPr 1, Piv-Pro-hAla-NHiPr 2, Moc-hPro-NHiPr 3, and Boc-hPro-Gly-N(OH)Me 4) deriving from the hydrazino analogues of glycine (hGly), L-alanine (hAla) or L-proline (hPro) have been solved. They reveal a common folded structure of the alpha-hydrazino acid residue characterized by a bifurcated hydrogen bond closing an eight-membered cycle. This folded structure is topologically similar to the beta II'-turn in peptides, and the CO-NH-N hydrazide link can be considered as a good turn-inducer in peptide analogues.

Hydrazines↗
PubMed1994

Turn induction by N-aminoproline. Comparison of the Gly-Pro-Gly and Gly psi [CO-NH-N]Pro-Gly sequences.

The folded structure induced by the N-aminoproline residue (the hydrazino analogue of proline, denoted hPro) in the Boc-Gly1-hPro2-Gly3-NHiPr hydrazino tripeptide has been characterized in the solid state by X-ray diffraction, and compared to the usual beta II-turn structure in the Boc-Gly1-Pro2-Gly36-NHiPr cognate tripeptide. It is stabilized by a bifurcated hydrogen bond in which (Gly3)NH interacts with both (Gly1)CO and (hPro2)N alpha. This conformation is retained in CH2Cl2 and CHCl3 solutions, and allows an overall folded conformation of the hydrazino tripeptide in which (iPr)NH is hydrogen-bonded to (Boc)CO. The hPro alpha-hydrazino acid residue appears to promote a local folded structure, and might behave as a beta-turn mimic.

Amino Acid Sequence↗
PubMed1994

[Measurement of vibratory threshold in the diagnosis of diabetic neuropathy].

The usefulness of the quantitative measurement of vibration perception threshold (VPT) was assessed by a biothesiometer in the diagnosis of peripheral neuropathy in 36 patients with type I diabetes mellitus. The study included: a) clinical assessment (history and neurological examination); b) measurement of VPT at right metatarsus, right pretibial area and right metacarpus; c) electromiographical study (right peroneal, posterior tibial, right sural, right medial plantar); d) assessment of the autonomous nervous system (sympathetic and parasympathetic indexes); e) metabolic assessment (HbA1c at study and mean HbA1c in the previous year). The prevalence of peripheral neuropathy was 38%. VPT at metatarsal region in diabetic patients was higher than in controls (p < 0.05) and a positive correlation with evolution time of disease at metatarsal region (p < 0.05) and tibia (p < 0.05) was observed. Clinical symptoms and changes at examination correlated with VPT at metatarsus (p < 0.05) and tibia (p < 0.05). No relationship was observed between VPT and metabolic control. In conclusion, vibration threshold increases with evolution time in diabetes, but it was not influenced by metabolic control. Its measurement by a simple method, such as biothesiometer, could be useful in diagnosing peripheral neuropathy in clinically asymptomatic patients.

Adult↗