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Biomedical subjects

F Martinez

Publications and source records attributed to F Martinez.

208 records · Page 12Linked to original sources
PubMedDate not supplied

Selective effect of mineralocorticoid replacement therapy on renal acid excretion in congenital adrenal hyperplasia.

The renal acid excretion of eight children with salt-losing congenital adrenal hyperplasia, was studied in three different situations: before treatment (period I), under glucocorticoid therapy (period II) and when both glucocorticoid and mineralocorticoid were given as replacement treatment (period III). Although administration of glucocorticoid therapy alone allowed the correction of acidemia, normalization of urinary net acid excretion was achieved only after mineralocorticoid was added to the treatment.

Acid-Base Equilibrium↗
PubMedDate not supplied

The monocyte/IgE connection: may polymorphisms in the CD14 gene teach us about IgE regulation?

BACKGROUND: Total IgE levels are known to be under genetic control. Linkage studies have indicated that one or more loci on chromosome 5q may control total IgE, as well as asthma and bronchial hyperresponsiveness to nonspecific stimuli. Our group has undertaken a systematic analysis of chromosome 5q, and has recently characterized five single nucleotide polymorphisms at position -1619, -1359, -1145, -809 and -159 in the promoter of the gene encoding CD14, the myeloid pattern recognition receptor that is critical for efficient innate immune response to lipopolysaccharide (LPS) and bacterial ligands. METHODS: Carriers of the major CD14 haplotypes were analyzed for serum levels of IgE and soluble CD14. In vitro IgE synthesis was assessed in peripheral blood mononuclear cells stimulated with IL-4 in the presence or absence of LPS or anti-CD14 monoclonal antibodies. RESULTS: An inverse correlation was found between serum levels of IgE and soluble CD14. On the other hand, in vitro IL-4-dependent IgE synthesis was strongly upregulated by LPS, but suppressed by anti-CD14 monoclonal antibodies. CONCLUSION: Our results highlight the complex role played by monocytes in IgE regulation.

Cells, Cultured↗
PubMedDate not supplied

Practical application of three polymorphic microsatellites in intron 40 of the human von Willebrand factor gene.

Intron 40 of the human von Willebrand factor gene contains a region with variable-number tandem repeats (VNTR), type (ATCT)n, showing length polymorphism. In order to carry out family studies of von Willebrand's disease, we performed PCR procedures to analyze 3 previously described microsatellites from that region, both in normal individuals and in von Willebrand disease patients. Three pairs of primers were used to amplify independently nucleotides 1890-1991 (VNTR 1), 2215-2380 (VNTR 2) and 1640-1794 (VNTR 3) from intron 40. The observed heterozygosities (0.75, 0.73 and 0.86 for VNTRs 1, 2 and 3, respectively) were in good agreement with the expected heterozygosities derived from the allele frequencies (0.70, 0.73 and 0.79, respectively). Furthermore, the combination of the 3 VNTRs showed 96% of heterozygosity, which correspond with the 98% expected value under linkage equilibrium. Therefore, our conclusion is that the use of these 3 markers, especially VNTR 3, constitutes a rapid and reliable method for performing segregation studies in von Willebrand disease families.

Alleles↗
PubMedDate not supplied

Pulse pressure responses in patients treated with Valsartan and hydrochlorothiazide combination therapy.

In a randomized, double-blind, parallel-group study of middle-aged and elderly patients, we examined the effects of treatment with the angiotensin receptor blocker valsartan (Val) in combination with hydrochlorothiazide (HCTZ) on pulse pressure (PP). After a 2-week washout period, patients entered a 4-week single-blind Val 160 mg once daily run-in period before randomization to one of three treatment groups: Val 160 mg (n = 666), Val 160 mg/HCTZ 12.5 mg (n = 670) or Val 160 mg/HCTZ 25 mg (n = 666), once daily for eight weeks. Sitting PP at baseline was similar in all groups. From baseline to randomization, Val monotherapy reduced PP by 4.7 +/- 10.2 mmHg (mean +/- SD). At the end of the study, overall reductions in PP were 6.7 mmHg for Val 160/HCTZ 12.5 and 7.5 mmHg for Val 160/HCTZ 25. Val monotherapy reduced PP in mild-to-moderate hypertensive patients. Val combined with HCTZ provides an additional dose-related reduction in PP.

Aged↗
PubMedDate not supplied

Ultrastructural study of the osteointegration of bioceramics (whitlockite and composite beta-TCP + collagen) in rabbit bone.

Study examines the osteointegration of two porous ceramic implants, beta-tricalcium phosphate (beta-TCP) and a composite (beta-TCP-collagen), in femur and tibias of 20 New Zealand white rabbits, which were sacrificed 1 week and 1, 4, and 12 months postimplant so that radiological, optical microscopic, and ultrastructural studies could be carried out. The results show a progressive degradation and resorption of both implant materials by means of a macrophagic reaction, which is at its most intense 1 month postimplant. The materials are substituted by newly formed bone tissue starting at the host bone-implant interface, the substitution being almost total by the end of the study, although less completely and earlier than in the case of the composite. Both materials can be considered as potential substitutes for bone tissue since they are biocompatible, bioreabsorbable, and osteogenic.

Animals↗
PubMedDate not supplied

[Pharmacokinetics of 3'-azido-3 deoxy-thymidine (AZT) in a patient undergoing hemodialysis].

Zidovudine (AZT) is the only effective drug in the treatment of AIDS. No data are available on the pharmacokinetics of this drug in patients with end-stage renal disease (ESRD). We report on the pharmacokinetics of zidovudine between sessions of hemodialysis and during the procedure in one patient with ESRD. In 1987 a 40-year-old man with ESRD treated with hemodialysis had the AIDS-related complex. The T4/T8 ratio was 0.49. An enzyme-linked immunosorbent assay and Western Blot studies revealed IgG antibodies specifically directed against HIV. The patient was then treated with zidovudine (100 mg three times daily). Studies of the pharmacokinetics of the drug, conducted between hemodialysis sessions, were performed on days 1 and 14 after the start of zidovudine treatment. Paired arterial and venous blood samples were obtained simultaneously one hour after the start of a hemodialysis session on day 20. The peak and the trough concentrations of zidovudine were 0.61 and 0.15 microgram per milliliter, respectively. We observed a marked accumulation of the main metabolite of zidovudine, G-AZT, with a concentration of about 65 micrograms per milliliter on day 14. The half-life was 2.9 hours. The hemodialysis clearance of zidovudine and its metabolite were 102 and 71 ml per minute, respectively. The half-life of zidovudine was three times longer in our patient than in a normal subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Possible protective role of calcium inhibitors in drug nephrotoxicity].

Many experimental studies have shown that calcium channel blockers could prevent drug-induced acute renal failure. In dog, nifedipine and verapamil prevent decreasing blood flow produced by contrast material. In rat, administration of verapamil has beneficial effects on gentamycin nephrotoxicity. Verapamil improves renal function in rats with acute renal failure due to cyclosporine. Calcium channel blockers have various effects on cisplatinum nephrotoxicity: in rat, nifedipine worsens nephrotoxicity; in man, verapamil prevents nephrotoxicity due to cisplatinum. In addition, nifedipine seems to improve renal function in transplanted patients treated with cyclosporine. In 2 control studies, we did not find any effect of diltiazem on prevention of renal toxicity due to methotrexate and cisplatinum. Calcium channel blockers could prevent nephrotoxicity by reducing calcium transfer across cell membranes and/or inhibiting the action of vasoconstrictive hormones.

Acute Kidney Injury↗
PubMedDate not supplied

Brainstem and middle latency auditory evoked responses in rabbits with halothane anaesthesia.

The effects of different concentrations of halothane (0.5, 1 and 1.5%) in brainstem and middle latency auditory evoked responses were studied in 14 adult rabbits. The animals were firstly curarized, tracheostomized and ventilated mechanically. Various recording were made under these conditions for control purposes. During the experiment, arterial pressure, temperature, arterial concentrations of O2, CO2 and pH were monitored. Halothane produce an increase in latency a decrease in amplitude and at higher concentrations even abolished the later waves of middle latency auditory evoked responses. Brainstem potentials are stable, but slight changes in latency were observed at high concentrations (1.5%). Modifications of these potentials as a result of the different concentrations of this anaesthetic in relation with the recordings obtained in the animals curarized without anaesthesia are discussed and the results compared with previous reports in humans.

Animals↗
PubMedDate not supplied

[Liver scanning].

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Carcinoma, Hepatocellular↗