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Biomedical subjects

J Navarro

Publications and source records attributed to J Navarro.

At least 253 records · Page 14Linked to original sources
PubMed1993

Nutritional assessment in Duchenne muscular dystrophy.

A specific-weight chart and simple clinical tools are sufficient to obtain an accurate diagnosis of undernutrition or obesity among patients with Duchenne muscular dystrophy (DMD). The authors collected weight-for-age measures from a sample of 252 boys and anthropometric data from 109 of those boys with DMD. The data confirm the accuracy of the DMD ideal-weight chart previously proposed by Griffiths and Edwards (1988). Obesity may occur from the age of seven years; its prevalence seems to reach 54 per cent by the age of 13 years. Undernutrition occurs after the age of 14 years, involving 54 per cent of boys at about 18 years of age. Obese boys show a centralized body-fat distribution, in agreement with other obese populations.

Adipose Tissue↗
PubMed1993

Arbitrarily primed polymerase chain reaction as a rapid method to differentiate crossed from independent Pseudomonas cepacia infections in cystic fibrosis patients.

We used DNA fingerprinting by the arbitrarily primed polymerase chain reaction (AP-PCR) technique for an epidemiological investigation of 23 Pseudomonas cepacia isolates obtained from 11 cystic fibrosis (CF) patients attending our CF center. This approach was compared with ribotyping, pulsed-field gel electrophoresis (PFGE), and conventional phenotypic typing. AP-PCR and ribotyping were identical in resolving power, since the two methods generated four different profiles and identified the same group of strains. Six patients on the one hand and four on the other harbored strains of the same genotype, thus raising the possibility of either patient-to-patient transmission or acquisition from a common hospital environmental source. PFGE results were in good agreement with those of the other two methods, but PFGE seems more discriminative since it generated a fifth profile for a single strain in a group of four. Our results show in vivo stability for the three methods during a period extending from 3 to 41 months. These genotypic techniques are particularly promising for clinical laboratories to help to clarify the epidemiology of P. cepacia in CF patients. The AP-PCR method constitutes an easier alternative to the well-established ribotyping method. AP-PCR provides the quickest results with minimal technical complexity. However, our results suggest that it is less discriminative than the labor-intensive PFGE method.

Base Sequence↗
PubMed1993

Liver cirrhosis in cystic fibrosis--therapeutic implications and long term follow up.

Experience gained from liver studies in 450 patients with cystic fibrosis, seen in a 38 year period from 1964 to 1992, is surveyed. Of these, 31 (7%) showed findings that indicated multilobular cirrhosis. There was a slight but not significant male predominance: 19 males against 12 females. Liver disease had its onset during childhood in most cases. The natural course of liver disease and of cirrhosis is protracted. All patients were routinely evaluated by way of: (i) clinical examination, (ii) biochemical studies and specifically estimation of transaminases and gamma glutamyltransferase, and (iii) liver imaging, ultrasonography, and computed tomography. The study aimed to detect early liver disease, that is multilobular cirrhosis and its complications, with a view to optimal introduction of treatment with ursodeoxycholic acid as this drug shows promise for preventing or stabilising the cirrhotic process. Effects of surgical treatment on portal hypertension are surveyed. These include portacaval shunting, partial splenectomy (considered the procedure of choice), liver transplant in the event of liver failure, or a triple transplant (liver, lungs, and heart) if necessary. One triple transplant was successfully performed in a boy of 10 years with a 2 year follow up.

Adolescent↗
PubMed1993

Regulation of sarcoplasmic reticulum calcium pump gene expression by hindlimb unweighting.

Hindlimb unweighting (HU) causes upregulation of several muscle-specific genes responsible for the slow-to-fast transition in soleus skeletal muscle properties despite the profound muscle atrophy. The purpose of this study was to examine the expression of the fast and slow isoforms of the sarcoplasmic reticulum Ca(2+)-ATPase at the mRNA and protein level in the soleus muscle over a time course of HU and relate them to Ca(2+)-dependent ATPase activity and selected contractile properties. mRNA levels of the acetylcholine receptor (AChR) were measured to compare the signal of unweighting with denervation. Atrophy of the soleus muscles from tail-suspended rats was observed at all time points with muscle mass decreased by 52% at 28 days of HU (P < 0.05). Northern blot analysis showed the relative expression of the fast Ca2+ pump mRNA increased by 0, 250, 910, 1,340, and 4,050% over control levels at 1, 4, 7, 14, and 28 days of HU, respectively, whereas changes in slow mRNA were variable and modest in comparison. For the same time points, Western blot analysis showed relative expression of the fast Ca2+ pump protein increased by 30, 110, 320, 280, and 300% over control levels, whereas the slow-pump protein expression was unchanged except for a 75% decrease at 28 days of HU. Specific Ca(2+)-dependent ATPase activity was increased (P < 0.05) by 170% at 28 days of HU. Contractile properties measured in vitro at 14 and 28 days revealed time to peak tension and one-half relaxation time were shortened (P < 0.05) and a rightward shift in the tension-frequency curves in unloaded soleus muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Exogenous cGMP prevents decrease in diuresis and natriuresis induced by inhibition of NO synthesis.

We previously demonstrated that the intravenous infusion of the specific inhibitor of nitric oxide (NO) synthesis, NG-nitro-L-arginine methyl ester (L-NAME), over a period of 60 min elevates mean arterial pressure (MAP) and reduces renal hemodynamics and excretory function. The objective of the present study was to determine the ability of a guanosine 3',5'-cyclic monophosphate (cGMP) analogue, 8-bromo-cGMP (8-BrcGMP), in preventing the increase in MAP and the reductions in renal plasma flow (RPF), glomerular filtration rate (GFR), urine flow (UV), and sodium excretion rate (UNaV) induced by intravenous infusion of L-NAME in rats. As expected, the infusion of L-NAME (50 micrograms.kg-1.min-1) increased (P < 0.05) MAP and reduced (P < 0.05) RPF, GFR, UV, and UNaV. The administration of 8-BrcGMP (100 micrograms.kg-1.min-1) and L-NAME resulted in no change in MAP, RPF, and GFR. However, decreased (P < 0.05) UV and UNaV were still observed. When 8-BrcGMP (200 micrograms.kg-1.min-1) and L-NAME were infused together, no significant changes in MAP or in renal function were observed. To prove the specificity of the 8-BrcGMP preventive effects, dibutyryl cAMP (200 micrograms.kg-1.min-1) and L-NAME (50 micrograms.kg-1.min-1) were infused together. Under these conditions, MAP, RPF, GFR, UV, and UNaV were modified in a manner similar to that observed during the infusion of L-NAME.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Normal calcitonin response to pentagastrin stimulation in patients with chronic renal failure.

High calcitonin levels have been reported in chronic renal failure. To study the C cell response in patients with chronic renal failure, an intravenous bolus of pentagastrin was administered to 11 patients and 11 healthy subjects. Samples were obtained at 0, 1, 2, 3, 5 and 10 min for calcitonin assay. In order to detect only the active monomeric calcitonin, an immunoradiometric assay method was used. The influence of calcium, phosphate, alkaline phosphatase and intact parathyroid hormone was also evaluated. Although basal calcitonin levels were higher (p < 0.01) in chronic renal failure (mean +/- SEM: 10.1 +/- 2.9 pmol/l) versus healthy subjects (1.1 +/- 0.3 pmol/l), the area under the curve showed there to be no differences between the two groups. The rising branch of the area under the curve, employed as an expression of the C cell response capacity, showed no differences either (chronic renal failure vs healthy subjects: 5.6 +/- 2 vs 2.6 +/- 0.7 pmol l-1 min-1, p = 0.28). In the chronic renal failure group, a positive correlation was found (r = 0.625, p < 0.05) between the rising branch of the area under the curve and parathyroid hormone. We conclude that monomeric calcitonin is increased in chronic renal failure, but C cells of the thyroid respond to pentagastrin, as they do in normal subjects. This finding is of great clinical importance when a patient with renal impairment is evaluated for medullary thyroid carcinoma. The calcitonin response to pentagastrin seems to be related directly to the degree of secondary hyperparathyroidism in chronic renal failure.

Adolescent↗
PubMed1993

Segregation analysis in a man heterozygous for a pericentric inversion of chromosome 7 (p13;q36) by sperm chromosome studies.

We have analyzed 140 sperm chromosome complements from a subfertile man heterozygous for an inv(7)(p13;q36). Seventy-five percent of the chromosome complements were not recombinant: 37.9% contained the normal chromosome 7, and 37.1% contained the inverted chromosome 7. Twenty-five percent of the 140 were recombinant: 7.1% carried a recombinant chromosome 7 with a duplication p and deletion q, 17.1% carried a recombinant chromosome 7 with a duplication q and deletion p, and 0.7% carried both recombinant chromosomes. The frequency of structural chromosomal aberrations unrelated to the inversion was 11.4%, and the frequency of aneuploidy was 2.9%. Both frequencies were not significantly different from those in control donors. Two sperm complements with a second independent, contiguous inversion involving one of the original breakpoints (q36) were observed (1.4%). The risk of producing chromosomally abnormal offspring or spontaneous abortions would be 34.3%. The proportion of X-bearing and Y-bearing sperm was 46.8% and 53.2%, respectively, not significantly different from the expected 1:1 ratio.

Adult↗
PubMed1993

Altered production of PGE2, IL-1 beta and TNF-alpha by peripheral blood monocytes from HIV-positive individuals at early stages of HIV infection.

We analyzed the in vitro synthesis and release of PGE2, IL-1 beta, and TNF-alpha by peripheral blood monocytes from HIV-infected injection drug users at the early clinical stages of HIV infection. We investigated whether there is a concomitant altered production of PGE2 and proinflammatory cytokines by HIV-positive monocytes. We also evaluated T-cell subsets and lymphocyte transformation response to pokeweed mitogen (PWM) in HIV-positive patients and healthy controls. PGE2 and IL-1 beta levels in supernatants from monocyte cultures were determined by radioimmunoassay (RIA), and TNF-alpha by enzyme immunoassay (EIA). Monocytes from asymptomatic HIV-positive individuals produced spontaneous and significantly increased quantities of PGE2, IL-1 beta, and TNF-alpha. Concomitant increased production of PGE2 and IL-1 beta by monocytes from HIV-positive asymptomatic patients was significantly associated with low CD4+ T-cell numbers (< 500 cells/mm3). We also found a strong association between spontaneous and concomitantly increased production of PGE2 and cytokines by monocytes from asymptomatic HIV-positive individuals and a low lymphocyte transformation response to PWM. Further studies are necessary to establish whether this altered production of PGE2 and proinflammatory cytokines by monocytes from HIV-positive individuals might play a role in the mechanisms involved in the progressive impairment of cell-mediated immunity in HIV infection.

Cells, Cultured↗
PubMed1993

[Current view and outlook for cystic fibrosis therapy].

Cystic fibrosis therapy has obtained in the last few years substantial benefits optimizing nutritional antibiotic and ventilatory techniques. With the discovery of the gene and of CFTR protein pharmacological approach may be initiated: correction of transmembrane ionic exchanges, and of sputum rheology. Gene therapy represents the last development, but rises methodological and ethical problems even if representing an important hope. Pulmonary transplant is only indicated in severe forms of cystic fibrosis.

Cystic Fibrosis↗
PubMed1992

Amino terminus of the interleukin-8 receptor is a major determinant of receptor subtype specificity.

Interleukin-8 (IL-8) is a key mediator in the migration of neutrophils from the circulation to the site of inflammation in the tissue. IL-8 is secreted by many cell types in response to proinflammatory stimuli such as interleukin 1, tumor necrosis factor, and lipopolysaccharide and is a potent chemoattractant and activator of neutrophils. Neutrophil activating peptide-2 (NAP-2) and melanoma growth-stimulatory activity (MGSA/GRO) are structurally and functionally related to IL-8 and, like IL-8, bind to specific G protein-coupled receptors on neutrophils. In the present study two closely related cloned IL-8 receptor subtypes are characterized by expression of the cDNA clones in monkey kidney cells (COS-7) or chinese hamster ovary cells and analysis of their ligand binding profiles. Both receptor subtypes bind 125I-labeled IL-8 with similar high affinity, however, the F3R receptor binds IL-8 exclusively, while the 4Ab receptor binds both IL-8 and MGSA/GRO with high affinity and NAP-2 with lesser affinity. Furthermore, we demonstrate with the use of intersubtype chimeric receptors that the specificity of ligand binding to both IL-8 receptor subtypes is dictated by the heterogeneous NH2-terminal domain. The F3R receptor is representative of a restricted IL-8 receptor subtype, and 4Ab represents a nonrestricted receptor subtype. It is proposed that these subtypes be named IL-8 receptors alpha and beta, respectively.

Amino Acid Sequence↗
PubMed1992

Functional expression of the bradykinin-B2 receptor cDNA in Chinese hamster lung CCL39 fibroblasts.

The bradykinin (BK) B2 receptor cDNA was synthesized by rt-PCR and transfected into the Chinese hamster lung fibroblasts, CCL39. The CCL39 do not contain the mRNA for this receptor and do not bind BK. Clones of transfected cells were screened for BK receptor mRNA, binding of BK, and for [Ca2+]i response to BK. The clones showed various levels of receptor mRNA. Scatchard analysis of three clones, B6, B5 and B1, each gave a Kd of approximately 1.0nM while the Bmax for each clone differed at 320, 38.7, and 5.39 fmoles per 10(6) cells respectively. The [Ca2+]i response of the three clones to BK decreased with the receptor number/cell. Thus, levels of mRNA, BK binding and [Ca2+]i response proved proportionally related in the transfected clones. The actions of BK and alpha-thrombin, which has an endogenous receptor in these cells, were assessed in clone B6. BK proved active but also distinct from thrombin. BK at 10nM and thrombin at 2units/ml both effectively increased cytosolic [Ca2+]i. BK at 10nM stimulated PGE2 production three fold over basal, while thrombin only marginally elevated PGE2 levels. Alone, BK stimulated a small increase in 3H-thymidine incorporation into DNA. However, in combination with insulin, BK stimulated DNA synthesis to 76% of thrombin, a potent mitogen in these cells. These results illustrate that the BK-B2 receptor cDNA can be stably transfected into a mammalian cell and can activate transmembrane signalling pathways.

Animals↗