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Biomedical subjects

J Navarro

Publications and source records attributed to J Navarro.

At least 181 records · Page 10Linked to original sources
PubMed1996

In situ management and molecular analysis of candidaemia related to a totally implantable vascular access in a cystic fibrosis patient.

We describe a case of candidaemia in a paediatric cystic fibrosis (CF) patient with a totally implantable vascular access (TIVA). Serial quantitative blood cultures during therapy with amphotericin B delivered via the catheter suggested that the patient was responding to therapy. The TIVA was finally removed because of persistent fever, but its culture remained sterile. Randomly amplified polymorphic DNA (RAPD) analysis of Candida albicans from various anatomical sites showed that the patient's sputum was the most likely source of TIVA contamination. Investigation of TIVA-related candidaemia by molecular analysis could guide rational antifungal chemoprophylaxis of TIVA-related candidaemia.

Amphotericin B↗
PubMed1996

Modulation of antibody-forming cell and mitogen-driven lymphoproliferative responses by dietary nucleotides in mice.

Several studies have demonstrated that dietary nucleotides play a role in maintaining T-cell dependent immunity. In this work, we investigated the effects of nucleotide supplementation of a nucleotide-free diet (NFD) on some immunity parameters in BALB/c mice. Twenty day old mice were maintained on diets for 30 days prior to use in experiments. The addition of nucleotide mixtures to NFD resulted in an increase in the response of hemolytic IgG-forming cells induced by previous immunization with sheep erythrocytes. When NFD was supplemented with single nucleotides, AMP, GMP, or UMP increased the IgG response, whereas CMP and IMP were without effect. GMP was the only nucleotide that increased the hemolytic IgM-forming cell response. Neither the contact hypersensitivity response to dinitrofluorobenzene nor the time of death after transplantation of a syngenic lymphoma was modified by nucleotide addition to NFD. The in vitro proliferative response of splenocytes to LPS was not affected by nucleotide supplementation of NFD, but the ConA-driven proliferative response was increased in mice fed NFD supplemented with nucleotide mixtures or with UMP. These data show that dietary mononucleotides stimulated at least some T-cell dependent immunity mechanisms. Moreover, these stimulatory effects may be obtained by supplementing a nucleotide-free diet with a mixture in which mononucleotides are at the same levels as in murine breast milk.

Animals↗
PubMed1996

[Contribution of endosonography to the diagnosis and follow-up of pediatric gastric neurofibroma revealing von Recklinghausen's disease].

BACKGROUND: Gastrointestinal involvement in von Recklinghausen's disease (RD) is rare during childhood; its symptoms are late and its prognosis is poor, related to local recurrence and risk of malignant transformation. CASE REPORT: A 13 year-old boy was admitted for hematemesis revealing gastric ulcer. A second episode of hematemesis led to identify a sessile gastric tumor in this patient having numerous skin café-au-lait spots. Recurrent bleeding required laparotomy that showed diffuse infiltration into the anterior gastric wall: histological examination of the excised piece showed characteristic features of neurofibromatosis. The patient was not compliant to the endosonographic survey so that a symptomatic relapse led to total gastrectomy: histological examination did not show malignant transformation. CONCLUSION: Endoscopy is a major tool for identifying gastrointestinal localization of RD but endosonography is necessary to precise the extent of the tumor.

Adolescent↗
PubMed1996

Pentoxifylline inhibits acute HIV-1 replication in human T cells by a mechanism not involving inhibition of tumour necrosis factor synthesis or nuclear factor-kappa B activation.

OBJECTIVE AND DESIGN: To study the in vitro activity of pentoxifylline (PTX), which may be of benefit in AIDS, on cell proliferation, tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma (a type 1 cytokine) and interleukin (IL)-10 (a type 2 cytokine) production, viral replication and CD4+ depletion in acutely HIV-1-infected human T cells. METHODS: T cells were stimulated with anti-CD3 antibody or phytohaemagglutinin (PHA) and infected with HIV-1 in presence or absence of PTX. Cell proliferation, CD4+ cell number, nuclear factor (NF)-kappa B activation, p24 antigen release or lymphokine content of the supernatants were evaluated by [3H]-thymidine incorporation, cytofluorimetry, electrophoretic mobility shift assays and specific enzyme-linked immunosorbent assay, respectively. RESULTS: In HIV-1-infected T cells, PTX inhibited cell proliferation and p24 release and prevented CD4+ depletion associated with HIV replication. Moreover, PTX reduced TNF-alpha, IFN-gamma and IL-10 production and NF-kappa B activation. PTX inhibited with similar potency IFN-gamma, TNF-alpha and cell proliferation. However, the inhibition of p24 release and specially of IL-10 production required significantly lower doses of PTX. Exogenous addition of IL-2 or TNF-alpha in presence of PTX restore T-cell proliferation and NF-kappa B activation respectively, but did not affect p24 inhibition. CONCLUSIONS: Our data suggest that the inhibitory effect of PTX on HIV replication cannot be satisfactorily explained by the inhibition of NF-kappa B or TNF-alpha. Moreover, PTX cannot be primarily considered as a TNF-alpha inhibitor and has several immunomodulatory and antiviral properties which could be of benefit against HIV-1 at various levels.

Antiviral Agents↗
PubMed1996

Resting energy expenditure before and after surgical resection of gut lesions in pediatric Crohn's disease.

In pediatric Crohn's disease (CD), resection of gut lesions is necessary to remove stenoses and when frequent relapses occur despite nutritional support and medical treatment. After surgery, improved nutritional status and accelerated growth usually follow increased nutritional intake and lower doses of steroids. The aim of this study was to compare energy balance before and after surgery while nutritional intake and steroid therapy were unchanged. Eleven patients, aged 14.5 +/- 2.5 years and with mildly active CD, were explored 1 week before and 1 month after gut resection for stenosis (n = 7) and medical treatment failure (n = 4). Eleven matched children participated in the study as controls. Disease activity was assessed by the Pediatric Crohn's Disease Activity Index and serum orosomucoid concentration. Resting energy expenditure (REE) was measured by indirect calorimetry, and fat-free body mass (FFM) was measured by anthropometry. The patients' mean REE decreased from 46.6 +/- 10.5 kcal/kg FFM/day before surgery to 42.6 +/- 10.3 kcal/kg FFM/day after surgery, while the controls' mean REE was 39 +/- 7 kcal/kg FFM/day (analysis of variance, p = 0.02). After surgery, body weights were not significantly different, but the mean protein oxidation rate was reduced and arm muscle area was increased. Changes in REE per kilogram of FFM per day were not correlated with changes in orosomucoid serum concentrations (r2 = 0.35; p = 0.4). In conclusion, in children with mildly active CD, while nutritional intake and steroid therapy were maintained at preoperative levels, a significant decrease in REE and improved nitrogen utilisation were observed 1 month after resection of the CD gut lesion. This finding suggests better use of energy substrates when CD lesions are removed.

Adolescent↗
PubMed1996

Quantification of low levels of human immunodeficiency virus (HIV) type 1 RNA in P24 antigen-negative, asymptomatic, HIV-positive patients by PCR.

A nested PCR was used to quantify small numbers of human immunodeficiency virus (HIV) type 1 (HIV-1) RNA particles in the serum specimens of 26 p24 antigen-negative, asymptomatic, HIV-positive patients undergoing antiretroviral therapy. Fifteen patients received zidovudine (ZDV) and alpha interferon, and 11 patients received ZDV monotherapy. After PCR, the amounts of RNA were quantified by comparing the endpoint dilutions of serum samples with a standard curve with known amounts of viral particles. Before the beginning of the antiviral therapy, HIV-1 RNA was detected in 92% of the patients. After treatment, a fall in the number of viral particles was detected in patients receiving combination therapy (mean titers +/- standard errors of the means, 3,617 +/- 756 pretherapy versus 1,800 +/- 845 posttherapy; P < 0.05) and in patients receiving monotherapy (3,763 +/- 642 pretherapy versus 1,353 +/- 394 posttherapy; P < 0.05). Our results indicate that PCR with nested primers may be useful for assessing the changes in viremia in HIV-positive patients with low viral load undergoing antiviral therapy.

Antiviral Agents↗
PubMed1996

An analysis of human sperm chromosome aneuploidy.

A sperm chromosome analysis of 24 men with normal or balanced karyotypes was carried out to study the frequency of sperm chromosome aneuploidy. A total of 3,446 human sperm complements (36-315 per donor) was analyzed after in vitro penetration of hamster eggs. Two sets of donors were studied at two different centers in the United States (center 1) and Spain (center 2). The frequencies of hyperhaploidy and hypohaploidy in control donors were similar between center 1 (1.9% vs. 7.7%) and center 2 (1.8% vs. 10.3%). In carrier donors there were no significant differences between the two centers in the frequency of hyperhaploidy (0.8% vs. 1.9%), but that of hypohaploidy was significantly higher in center 2 (11.0%) than in center 1 (4.6%). A significant excess of hypohaploid complements, as compared to hyperhaploid complements, was found in both centers in both control and carrier donors. The sex ratio was similar in both centers and did not differ significantly from a 1:1 sex ratio. The larger chromosomes in the complement (1, 2, 3, 4, 5, 7, and 10) presented a significantly lower frequency of hypohaploidy, while some of the smaller chromosomes (13, 19, and 21) showed a higher frequency of hypohaploidy than expected. Chromosome 21 and the sex chromosomes showed an increase in the percentage of hyperhaploidy, as compared to other chromosomes, that was close to statistical significance (P = 0.08). Our results reflect a preferential loss of small chromosomes during slide preparation and suggest that chromosome 21 and the sex chromosomes could be more frequently involved in aneuploidy.

Aneuploidy↗
PubMed1996

Assessment of iron status in children and adolescents with Crohn's disease: value of basic red cell ferritin.

The iron status of 22 children and adolescents with Crohn's disease (mean age: 13 years) was evaluated. Eleven patients were suffering from active disease with inflammation, identified by at least one abnormal value for serum orosomucoid, C-reactive protein or sedimentation rate (group I). Eleven patients were in clinical remission and showed no biological evidence of inflammation (group II). Hemoglobin and red cell indices, erythrocyte protoporphyrin, serum iron, transferrin, serum ferritin and basic red cell ferritin were determined in all patients. The usual indicators of iron status, particularly serum ferritin, were affected by the inflammatory processes, but basic red cell ferritin appeared to be independent of inflammation. Basic red cell ferritin can therefore be considered to be a reliable indicator of iron status in children and adolescents with Crohn's disease.

Adolescent↗
PubMed1996

Relationship of virologic, immunologic, and clinical parameters in infants with vertically acquired human immunodeficiency virus type 1 infection.

We have investigated the relationship among the HIV-1 biologic phenotype, replicative capacity of virus isolates, HIV-RNA copy number in plasma, p24 antigenemia, CD4+ T lymphocyte counts in peripheral blood, and the clinical status in a cohort of 13 HIV-infected children younger than 12 mo of age, born of HIV-1 seropositive mothers. Six out of 13 HIV-1 isolates from these patients were classified as rapid/high and seven as slow/low. We have found a significantly positive correlation between the replication rate of HIV isolates and their capacity to induce syncytia in vitro. Most of the serial HIV-1 isolates obtained from infants with AIDS had the rapid/high phenotype and induced syncytia, whereas only two out of 23 HIV-1 isolates obtained from infants without AIDS showed these properties. In sequential analysis of HIV-1 isolates from infants with AIDS, the presence of viral isolates with rapid/high and SI phenotype was associated with higher levels of HIV-1 RNA in plasma, CD4+ T cell depletion, and clinical progression. By contrast, infants whose viruses exhibited nonsyncytium-inducing phenotype throughout the follow-up showed lower levels of HIV RNA, stable CD4+ T cell counts, and mild symptomatic HIV infection. Our findings indicate that infants who carried viruses with more cytopathic biologic phenotype and who had higher viral RNA coy numbers in blood were more likely to have lower CD4+ T cell counts and more likely to have AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Elevated levels of circulating intercellular adhesion molecule 1 and tumor necrosis factor alpha in the serum of children vertically infected with HIV-1.

OBJECTIVE: To evaluate serum levels of circulating intercellular adhesion molecule-1 (cICAM-1) and tumor necrosis factor-alpha (TNF-alpha) levels in HIV-1-infected children at different stages of infection in children treated or not treated with Zidovudine (ZDV). DESIGN: Serum levels of cICAM-1 and TNF-alpha, determined by enzyme immunoassays, were evaluated in 52 HIV-1-infected children, aged between 1 month and 13 years; 35 children were not treated with ZDV and 17 were treated with ZDV. RESULTS: cICAM-1 (596 +/- 41 ng/ml) and TNF-alpha (284 +/- 29 pg/ml) levels were significantly elevated in HIV-1-infected children compared with HIV-1-uninfected age-matched controls (cICAM = 295 +/- 17 ng/ml; TNF-alpha = 4.8 +/- 0.89 pg/ml). No significant differences in either parameter were observed between children at different stages of HIV-1 disease. By contrast, a marked statistically significant, reduction of cICAM and TNF-alpha levels was observed in HIV-infected children undergoing antiretroviral therapy. CONCLUSIONS: Serum levels of cICAM-1 and TNF-alpha were significantly elevated in HIV-1-infected children regardless of their clinical stage. Moreover, antiretroviral treatment appeared to reduce the serum levels of cICAM-1 and TNF-alpha.

Adolescent↗
PubMed1996

Chronic effects of nitric oxide and prostaglandin inhibition on pressure diuresis and natriuresis in rats.

The long-term interaction between nitric oxide (NO) and prostaglandins (PGs) in the pressure diuresis and natriuresis response has been studied. Experiments were performed in rats with chronic (8 weeks) inhibition of NO (NG-nitro L-arginine methyl Ester, L-NAME, 40 mg/kg/day) with or without simultaneous PGs synthesis blockade (indomethacin, 1 mg/kg/day). A time control group with no treatment was studied in parallel. At the end of this period, the animals were anesthetized and renal hemodynamics and excretion were studied at three levels of renal perfusion pressure (RPP; 100, 125 and 150 mm Hg). Renal blood flow, glomerular filtration rate, diuresis and natriuresis were lower at the three RPP levels in both L-NAME-treated groups than in the control or indomethacin-treated animals. Simultaneous administration of indomethacin plus L-NAME did not further modify the hemodynamic or excretory responses observed in the L-NAME-treated animals. These results show that chronic NO inhibition impairs the renal excretory response to changes in renal perfusion pressure, and simultaneous NO and prostaglandin synthesis inhibition does not reduce those responses further. It is concluded that, on a long-term basis, a preserved NO production, but not prostaglandin production, is critical for a normal pressure diuretic and natriuretic mechanism.

Animals↗
PubMed1996

Is nasal polyposis in cystic fibrosis a direct manifestation of genetic mutation or a complication of chronic infection?

Cystic fibrosis (CF) is the most common autosomal recessive disease among Caucasians. It is characterized by abnormal transepithelial sodium and chloride transport. The clinical expressions of the disorder are highly variable including nasal polyposis. Some authors have found that CF children with nasal polyposis form a distinct subgroup of patients within the clinical heterogeneity of the disease with milder gastrointestinal and pulmonary symptoms. The aim of this prospective study was to verify whether the clinical manifestations in CF children with nasal polyposis are different from control CF patients, and to identify any correlation between a phenotype of nasal polyposis and a genotype. Sixty-six CF children, aged 1-25 years, consecutively underwent ENT examination including nasal endoscopy. Twenty-one had nasal polyposis. The remainder formed the control group. There was no statistical difference in the mode and age of presentation of the disease between the two groups. The clinical manifestations (Schwachman and Kulczycki score, colonization by Staphylococcus aureus and Pseudomonas aeruginosa) were comparable between the two groups. We found no statistical difference in the repartition of genotypes between the polyposis and the control groups. Nasal polyposis does not seem to be genetically dependent, but a larger sample of patients is needed to reach an accurate conclusion.

Adolescent↗
PubMed1995

[Winter epidemic of carbon monoxide poisoning in Badia].

OBJECTIVE: To find the incidence, morbidity and possible causes of the acute carbon monoxide poisonings (ACMP) which occurred in Badia between january 1992 and june 1993. DESIGN: A longitudinal, retrospective study. PATIENTS: Every Badia resident discharged from the Hospital Consortium of Parc Taulí, Sabadell with a diagnosis of ACMP and/or from Barcelona's Red Cross Hospital (RCH) after hyperbaric treatment was considered. MEASUREMENTS AND RESULTS: Cases were identified using the hospital discharge records from Parc Taulí and the RCH. A systematic review of the primary care clinical records was undertaken. The causes of the poisoning were investigated by a technical committee and through the gas company carrying out inspections of dwellings in 1993. The incidence of ACMP was 76.5 per 100,000 inhabitants in 1992 and 109.4 per 100,000 in the first half of 1993. 94% of the 34 cases occurred in December, January, February and March. 50% of those affected were under 17. The number of cases per household varied between 2 and 5 people. The most common underlying cause was the existence of defects in the conduits taking fumes away from gas heaters. The gas review detected defects in installation in 54% of dwellings. CONCLUSIONS: ACMP is a common and serious problem in our environment. The underlying causes and the high number of dwellings at risk have suggested a need for information campaigns in the community.

Adolescent↗