Search PubMed⌕ Search

Biomedical subjects

F Martinez

Publications and source records attributed to F Martinez.

At least 91 records · Page 5Linked to original sources
PubMed1997

The GyneFix implant systems for interval, postabortal and postpartum contraception: a significant advance in long-term reversible contraception. International Study Group on Intrauterine Drug Delivery.

Intrauterine contraception has a number of important advantages over other forms of contraception and remains, therefore, an important method of birth control. However, side-effects and other drawbacks have reduced its overall acceptance. Also misconceptions and lack of updated scientific knowledge among the potential users and providers are major obstacles to the widespread use of intrauterine contraception. Ideally, an intrauterine device (IUD) should prevent pregnancy effectively, be well tolerated, not become displaced or expelled over time, cause a minimum of side-effects, be long-lasting, have a strictly local effect, and be easy to insert and remove. A group at the University of Ghent, Belgium, the International Study Group on Intrauterine Drug Delivery, has developed, since 1985, a totally new concept in order to improve current intrauterine contraceptive efficacy and enhance tolerance, by creating a harmonious relationship between the uterine cavity and the contraceptive 'foreign body'. The new concept (GyneFix) consists of a non-biodegradable suture thread made of surgical 00 monofilament polypropylene on which six copper tubes are threaded, providing a total surface area of 330 mm2. The upper and lower tubes are crimped onto the thread to keep the tubes in place. The upper extremity of the thread is provided with a knot which serves as an anchor. The knot is implanted in the myometrium of the uterine fundus with a specially designed insertion instrument, thereby permanently securing the device in the uterine cavity. Since the initial clinical investigations, over 10,000 woman years of experience and up to 10 years' follow-up in international multicenter, non-comparative and comparative clinical trials have been collected. The clinical material also included a large number of nulligravid and nulliparous women. Due to the design characteristics of the GyneFix and its anchoring in the uterine fundus, an optimal tolerance and almost complete absence of expulsion were obtained. The constant release of copper ions in the upper part of the uterine cavity results in the high effectiveness of the anchored device. The effectiveness is higher than in the high-load conventional copper IUDs which have a risk of becoming displaced, partially or totally expelled in 10% or more (nulliparous women), resulting in a significant number of accidental pregnancies. The absence of frame and, as a consequence, its flexibility, explain the low incidence of side-effects and the very low incidence of complications, such as pelvic inflammatory disease and ectopic pregnancies. This new concept could be a major step forward in the acceptance of intrauterine contraception worldwide and increase its popularity. This article reviews the experience with the new concept for interval, postabortal and postpartum contraception.

Abortion, Induced↗
PubMed1997

Responsibility of health providers and the media in response to scientific information.

During the last 2 years, there have been a number of reports on oral contraceptives (OCs) and their effects on breast cancer and vascular events. The pill scare that followed the controversy of the third-generation combined OCs has produced immeasurable amounts of medical publications and public mass media coverage, all showing great disparity on the aspects that they have emphasized. It would seem that personal points of view, whether or not they are associated with other interests, and not directly related to the nature of the scientific information, could lead to opposed interpretations of the same facts and would lead the reader to perceive a different message. The consequences of over-reporting the adverse effects of oral contraceptives on the general population, such as pill discontinuation and a rise in abortion rates, deserve special consideration in regard to the responsibility of health professionals and the mass media in the diffusion of scientific information. The aim of this paper is to analyze the repercussions of the diffusion of scientific information about oral contraceptives on the general public and the responsibility of health professionals and the mass media, and to propose some considerations to be taken into account when giving scientific information on oral contraceptives.

Bias↗
PubMed1997

Ureteral lesion secondary to vaginal ultrasound follicular puncture for oocyte recovery in in-vitro fertilization.

Techniques of oocyte retrieval have progressed from laparoscopy to transvaginal follicular aspiration under ultrasonographic control. This highly efficient method, routinely used nowadays, is not free of complications. We present a case of a ureteral lesion secondary to vaginal ultrasound follicular puncture for oocyte recovery in in-vitro fertilization. Despite the surgical procedure to reimplant the ureter, the patient achieved a twin pregnancy which is ongoing uneventfully.

Adult↗
PubMed1997

Worldwide variations in prevalence of symptoms of allergic rhinoconjunctivitis in children: the International Study of Asthma and Allergies in Childhood (ISAAC).

BACKGROUND: As part of the International Study of Asthma and Allergies in Childhood (ISAAC), prevalence surveys were conducted among representative samples of school children from locations in Europe, Asia, Africa, Australia, North and South America. SUBJECTS: 257,800 children aged 6-7 years from 91 centres in 38 countries, and 463,801 children aged 13-14 years from 155 centres in 56 countries. METHODS: Written symptom questionnaires were translated from English into the local language for self-completion by the 13-14-year-olds and completion by the parents of the 6-7-year-olds. Rhinitis was described as a problem with sneezing, or a runny, or blocked nose when you (your child) DID NOT have a cold or the flu. Additional questions were asked about rhinitis associated with itchy-watery eyes, interference with activities and a history of hay fever ever. RESULTS: The prevalence of rhinitis with itchy-watery eyes ("rhinoconjunctivitis") in the past year varied across centres from 0.8% to 14.9% in the 6-7-year-olds and from 1.4% to 39.7% in the 13-14-year-olds. Within each age group, the global pattern was broadly consistent across each of the symptom categories. In centres of higher prevalence there was great variability in the proportion of rhinoconjunctivitis labelled as hay fever. The lowest prevalences of rhinoconjunctivitis were found in parts of eastern Europe, south and central Asia. High prevalences were reported from centres in several regions. CONCLUSION: These results suggest substantial worldwide variations in the prevalence and labelling of symptoms of allergic rhinoconjunctivitis which require further study. These differences, if real, may offer important clues to environmental influences on allergy.

Adolescent↗
PubMed1997

Low urine flow reduces the capacity to excrete a sodium load in humans.

Recent studies in rats suggest that vasopressin and the resulting urinary concentrating activity reduce the capacity of the kidney to excrete sodium. The present study investigates the influence of the level of hydration on the excretion of a sodium load in humans. Eight healthy male volunteers (18-35 yr) were studied twice, in random order, under either low (LowH) or high (HighH) hydration. They drank throughout the study either 0.25 (LowH) or 2.0 ml water/kg body wt (HighH) every 30 min. After 1 h equilibration, urine was collected for 2 h before (basal) and 10 h after the NaCl load (5 g NaCl in 250 ml, infused intravenously over 30 min). Differences in excretory patterns between LowH and HighH were mostly confined to the first 4 h after the load. The increase in Na excretion after the load was more intense under HighH than under LowH (+ 10.9 +/- 2.6 vs. + 5.8 +/- 2.7 mmol/h in the first 4 postload h; P < 0.001). Under HighH, urine flow rate (V) increased markedly (+ 41%), with little change in urinary Na concentration (UNa), whereas under LowH, V declined slightly and UNa rose significantly (+ 33%). The capacity to raise UNa seemed to reach a maximum at approximately 280 mM. In both conditions, the changes in UNa observed after the load were positively correlated with basal UNa. After the load, urea excretion increased under HighH and decreased under LowH, whereas K excretion was unaffected in either condition. These results show that sodium excretion is facilitated by an abundant water supply. The less efficient sodium excretion occurring at low V is probably due to the influence of vasopressin on water, urea, and sodium movements across the collecting ducts. These observations suggest that, in everyday life, a low water intake could limit the capacity to excrete sodium. Whether this could contribute to salt-sensitive hypertension remains to be evaluated.

Adult↗
PubMed1997

Lung volume reduction surgery alters management of pulmonary nodules in patients with severe COPD.

OBJECTIVE: To examine the role of lung volume reduction surgery (LVRS) in expanding the treatment options for patients with single pulmonary nodules and emphysema. METHODS: Retrospective review of all patients undergoing LVRS at the University of Michigan between January 1995 and June 1996. Those undergoing simultaneous LVRS and resection of a suspected pulmonary malignancy formed the study group and underwent history and physical examination, pulmonary function tests, chest radiography, and high-resolution CT of the chest. If heterogeneous emphysema was found, cardiac imaging and single-photon emission CT perfusion lung scanning were performed. All study patients participated in pulmonary rehabilitation preoperatively. Age- and sex-matched patients who had undergone standard lobectomy for removal of pulmonary malignancy during the same period formed the control group. RESULTS: Of 75 patients who underwent LVRS, 11 had simultaneous resection of a pulmonary nodule. In 10 patients, the nodules were radiographically apparent with 1 demonstrating central calcification. Histologic evaluation revealed six granulomas, two hamartomas, and three neoplastic lesions (one adenocarcinoma, one squamous cell, and one large cell carcinoma). Preoperative FEV1 was 26.18+/-2.49% predicted in the LVRS group and 81.36+/-6.07% predicted (p=0.000001) in the control group, and the FVC was 65.27+/-5.17% predicted vs 92.18+/-5.53% predicted (p=0.002). Two LVRS patients had a PaCO2 >45 mm Hg while 11 exhibited oxygen desaturation during a 6-min walk test. Postoperative complications occurred in two LVRS patients and three control patients. The mean length of stay in the LVRS group (7.55+/-1.10 days) was not different than in the control group (8.81+/-1.56 days). Three months after LVRS and simultaneous nodule resection, FEV1 rose by 47%, FVC by 25%, and all study patients noted less dyspnea as measured by transitional dyspnea index. CONCLUSIONS: Simultaneous LVRS and resection of a suspected bronchogenic carcinoma is feasible and associated with minimal morbidity and significantly improved pulmonary function and dyspnea.

Aged↗
PubMed1997

Molecular analysis of snRNAs and scRNAs using autoantibodies from patients with systemic lupus erythematosus.

Immunoprecipitation analysis of total HeLa cells RNA extract by protein A-Sheparose purified autoantibodies and pCp 32P-3' end labeling RNAs revealed that U1, U2, U4 and U5 snRNAs are related with anti-Sm or U1nRNP autoantibodies, while the hY1, hY3, hY4 and hY5 scRNAs were related to anti-SSA/Ro autoantibodies present in sera of patients with Systemic Lupus Erythematosus. The authors detected molecular snRNAs and scRNAs specificities by autoantibodies in 71 sera, the molecular RNA specificity for anti-Sm (U1, U2, U4 and U5 snRNAs) was present in 39%; anti-SSA/Ro sera reacted against scRNAs (hY1, hY3, hY4 and hY5) in 36%, then anti-U1nRNP sera recognized U1 snRNA in 13% of sera and anti-rRNP related with rRNA were recognized in 8%. Twenty-nine SLE sera were RNA negative. A molecular characterization of the autoantibodies in sera from SLE patients may be a useful tool for clinical and laboratory diagnosis of SLE, and the use of autoantibodies as molecular probes allows to continue exploring some basic mechanism of gene expression.

Autoantibodies↗
PubMed1997

Acute hepatitis during hypersensitivity syndrome due to midecamycin.

We report here the first case of symptomatic acute hepatic injury due to midecamycin in a 58-year-old man. The clinical picture was compatible with a hypersensitivity syndrome with cutaneous, renal and hepatic involvement. Liver eosinophil polynuclear infiltrate, hypereosinophilia and acute interstitial nephritis were consistent with the hypothesis of an immunoallergic mechanism.

Acute Disease↗
PubMed1997

Study of a trimeric tandem repeat locus (SBMA) in the Basque population: comparison with other populations.

Microsatellites can be highly unstable and show a high level of polymorphism between individuals. Here we present the analysis of the CAG trinucleotide repeat polymorphism at the SBMA locus in 57 phenotypically normal individuals rigorously assigned to the Spanish Basque population. Results are compared with 100 Spanish non-Basque individuals who were already analyzed by us (175 alleles). This is the first study undertaken in these populations for this marker. In addition, we compared our results with those published for other populations. Relative allele frequencies showed differences between the samples and no unimodal distribution. The expected heterozygosity in the Basque sample was slightly lower than in the non-Basque sample. Conformity with Hardy-Weinberg equilibrium was verified by three tests. When compared with published data, the predominant alleles appear to be the same in the various populations. There are more differences between Basques and other Caucasoid samples than between non-Basques and Caucasoid samples. Population relationships were also examined by dendrograms based on genetic distances. The results obtained showed some peculiarities in the Basque population. The high degree of similarity with other dendrograms based on different markers and the efficiency of this STR marker in differentiating closely related populations, support the potential usefulness of microsatellites as tools for human population studies.

Ethnicity↗
PubMed1996

Alterations of the mucosal immune system due to Cryptosporidium parvum infection in normal mice.

The mechanism with which the immune system of an immunocompetent host responds to Cryptosporidium parvum infection is still poorly understood. We have therefore investigated the immune response of adult immunocompetent C57BL/6 mice at Days 6 and 10 to postinfection during a self-limiting C. parvum infection. We evaluated the immune changes at the levels of intestinal intraepithelium and lamina propria as well as mesenteric lymph nodes. At Day 6 postinfection, there was a decrease in the production of IFN-gamma, IL-5, IL-6, and IL-10 by in vitro mitogen-stimulated intraepithelial lymphocytes. Moreover, an increase in the number of gammadelta-TCR+, CD8+, and cytoplasmic IgE+ cells in intestinal lamina propria was found. Concomitantly, a significant decrease in the number of cytoplasmic IgA+ and IgG+ cells was observed. These phenotypic changes may be associated with the cytokine-producing profile (decreased IL-4, IFN-gamma, and IL-10) by lamina propria lymphocytes. At Days 6 and 10 postinfection cytoplasmic IgA+ and IgG+ cell numbers remained. Nevertheless, the production of IL-5 and IL-10 by intraepithelial lymphocytes was higher than the noninfected control values; these changes may be associated with the decreased CD4+ cell numbers. In mesenteric lymphocytes IgG and IgA production in vitro was elevated while no changes were observed in cytokine production except for a significant decrease in IL-5. In conclusion, our results demonstrate that an immunocompetent defense mechanism leading to a successful recovery from C. parvum infection involved changes of T(H1)- or T(H2)-type cytokine production as well as alterations of the lymphocyte subpopulation at mucosal-associated lymphoid tissues.

Animals↗
PubMed1996

Renal effects of angiotensin I-receptor blockade and angiotensin convertase inhibition in man.

1. The objective was to compare two means of inhibition of the renin-angiotensin system [angiotensin-converting enzyme inhibition and selective antagonism of angiotensin II subtype 1 (AT1) receptor] on renal function in 10 healthy normotensive volunteers on a normal sodium diet. Since mechanisms of action may differ between both drugs, a synergistic action was further studied by combining the two drugs. 2. The design was a double-blind randomized acute administration of either placebo or a single oral dose of enalapril, 20 mg, followed in each case by administration of the AT1 selective antagonist losartan potassium, 50 mg orally. 3. The methods included measurements of hormones (plasma renin activity, plasma aldosterone), blood pressure and renal function from 45 to 135 min after administration of placebo or enalapril, and from 45 to 135 min after losartan and placebo or losartan and enalapril. Renal function was studied using clearance of sodium, lithium, uric acid, inulin and para-aminohippuric acid. To examine further the determinants of glomerular filtration at the microcirculation level, fractional clearance of neutral dextran was determined and sieving curves were applied on a hydrodynamic model of ultrafiltration. 4. Losartan did not change plasma renin activity, blood pressure or glomerular filtration rate, but increased significantly renal plasma flow and urinary excretion of sodium and uric acid. Enalapril increased plasma renin activity and renal plasma flow, and decreased blood pressure without natriuretic, lithiuretic or uricosuric effects. The renal vasodilatation was potentiated when losartan and enalapril were combined, despite a further rise in plasma renin. In contrast to enalapril, losartan either alone or in combination with enalapril significantly depressed fractional clearances of dextran of small radii (34-42 A). These changes in fractional clearances of dextran were presumably related to the rise in glomerular plasma flow since the other major determinants of filtration, i.e. transcapillary glomerular pressure gradient, ultrafiltration coefficient and membrane property, were computed as unchanged by either losartan, enalapril or a combination of both. 5. In conclusion, these findings suggest that in normal sodium-repleted man the renal, hormonal and blood pressure effects of AT1 antagonism and angiotensin-converting enzyme inhibition are not strictly similar and could be synergistic.

Adult↗
PubMed1996

Chronic effects of endothelin-3 on blood pressure and renal haemodynamics in rats.

BACKGROUND: Renal vasoconstriction and systemic hypertension are well-known effects of bolus or short-term endothelin administration. However, the role of endothelin as a circulating hormone remains largely unknown. METHODS: The present study explores the effects of endothelin-3 (ET-3) on renal haemodynamics and systemic blood pressure during a 3-h and a 3-day intravenous infusion in rats. Male Sprague-Dawley (SD) rats were infused with vehicle (group 1) or ET-3 (group 2), 10 ng/kg per min; group 3, 50 ng/kg per min) delivered via osmotic minipumps into the right jugular vein for 3 days. On day 3 after pump implantation, rats were anaesthetized with Inactin and surgically prepared for assessment of mean arterial blood pressure (MABP), renal plasma flow (RPF), glomerular filtration rate (GFR), and renal vascular resistance (RVR). The same parameters were assessed during a 3-h ET-3 infusion study in SD rats (group 4, vehicle; group 5, ET-3, 10 ng/kg per min; group 6, ET-3, 50 ng/kg per min). RESULTS: In 3-day infused rats, ET-3 induced a significant decrease in RPF (-22+/-7% and -26+/-8% for group 2 and group 3 respectively, P<0.05 vs group 1) and an increase in RVR (+40+/-11% for groups 2 and 3; P<0.05 vs group 1); 50 ng/kg per min ET-3 significantly decreased GFR (-17%, P<0.05 vs group 1). MABP was not significantly affected by endothelin infusion. In acute infusion studies a decrease of the same magnitude was seen for the renal haemodynamics values. 50 ng/kg per min ET-3 increased MABP; a systemic effect that disappeared after the 3-day infusion. CONCLUSIONS: This study suggests that intravenously administered ET-3 in the rat has only a transient effect on systemic blood pressure, whereas it induces alterations in renal haemodynamics after both acute and chronic perfusions.

Animals↗
PubMed1996

Placental steroid hormone synthesis: unique features and unanswered questions.

Despite the amazing diversity of placental architecture across species, a number of common elements can be found, including the ability of all placentae to synthesize and metabolize steroid hormones; the assignment of steroidogenic activities to specific trophoblast phenotypes; the use of novel mechanisms to control expression of steroidogenic enzyme genes, which differ from those employed in the adrenal cortex and gonads; and interactions with the maternal and fetal compartments encompassing supply of steroid hormone precursors as well as regulatory influences of maternal ovarian and pituitary hormones and fetal adrenal cortical steroids.

Animals↗