Search PubMed⌕ Search

Biomedical subjects

F Martinez

Publications and source records attributed to F Martinez.

At least 55 records · Page 3Linked to original sources
PubMed2000

Stimulation protocols for poor responders and aged women.

There is a general consensus on the clinical fact that the more embryos replaced the higher pregnancy rates are achieved. For this reason those IVF cycles with a low response and a reduced number of oocytes and embryos will have very few chances of producing a pregnancy. It is very important to diagnose, by means of the anamnesis and hormonal tests which patients are most likely to present a poor response to conventional ovarian stimulation protocols. It is mandatory to know the patient's plasmatic levels of FSH and estradiol together with personal data such as the age and the previous history of the patient. Only young poor responders with a normal basal hormonal profile will have some chances that by applying new protocols and combining new drugs, improve their response and have higher pregnancy rates. For the old poor responders who have already failed to alternative protocols including natural cycles, oocyte donation is the last and best hope.

Adult↗
PubMed2000

Maternal asthma status alters relation of infant feeding to asthma in childhood.

The relation of infant feeding to childhood asthma is controversial. This study tested the hypothesis that maternal asthma alters the relation of breastfeeding to childhood asthma. Questionnaires were completed at age 6, 9 or 11 years by parents of 1043 children enrolled at birth. Active MD asthma was defined as a physician diagnosis of asthma plus asthma symptoms reported on one of the questionnaires. Duration of exclusive breastfeeding, categorized as never, < 4 months, or > or = 4 months, was based on prospective physician reports or questionnaires completed at 18 months. The relationship between breastfeeding and asthma differed by maternal asthma status. For children with maternal asthma, the percent developing active MD asthma increased significantly with longer duration of exclusive breastfeeding. Odds of developing asthma among these children were significantly elevated (OR: 5.7,CI: 2.8-11.5), after adjusting for confounders. This association of longer exclusive breastfeeding with increased risk of reported asthma among children with asthmatic mothers may be biologically based, or may reflect reporting biases.

Asthma↗
PubMed2000

Embryo transfer under ultrasound guidance improves pregnancy rates after in-vitro fertilization.

Between October 1998 and January 1999, we examined the influence of ultrasound guidance in embryo transfer on pregnancy rate in 362 patients from our in-vitro fertilization (IVF)-embryo transfer programme. These patients were prospectively randomized into two groups: 182 had ultrasound-guided embryo replacement, and 180 had clinical touch embryo transfer. There were no statistically significant differences between the two groups with respect to age, cause of infertility and in the characteristics of the IVF cycle. The pregnancy rate was significantly higher among the ultrasound-guided embryo transfer group (50%) compared with the clinical touch group (33.7%) (P < 0.002). Furthermore, there was also a significant increase in the implantation rate: 25.3% in the ultrasound group compared with 18.1% in the clinical touch group (P < 0.05). In conclusion, ultrasound assistance in embryo transfer significantly improved pregnancy and implantation rates in IVF.

Adult↗
PubMed2000

Transjugular versus percutaneous renal biopsy for the diagnosis of parenchymal disease: comparison of sampling effectiveness and complications.

PURPOSE: To compare the effectiveness and safety of transjugular renal biopsy with those of percutaneous renal biopsy for diagnosis of renal parenchymal disease. MATERIALS AND METHODS: Results and complications of 400 consecutive transjugular renal biopsies performed between 1993 and 1998 with a modified Colapinto transjugular hepatic biopsy system were compared retrospectively with those of 400 percutaneous renal biopsies performed during the same period. Transjugular renal biopsy was associated with 14 cardiac and 35 hepatic biopsies. Number of glomeruli per tissue core, adequacy of tissue core for histopathologic diagnosis, and rate and severity of complications were analyzed. RESULTS: Renal tissue was obtained with percutaneous renal biopsy in 382 (95.5%) of 400 patients and with transjugular renal biopsy in 383 (95.8%) of 400 patients. The mean numbers of intact glomeruli per tissue core with optical microscopy were 11.2 +/- 7.7 (SD) and 9.8 +/- 7.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. With immunofluorescent microscopy, the mean numbers were 6.4 +/- 5.3 and 4.6 +/- 4.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. Tissue cores were adequate for histopathologic diagnosis in 98.2% with both techniques. Major complications occurred with transjugular renal biopsy in four patients and with percutaneous renal biopsy in three patients. CONCLUSION: Use of transjugular renal biopsy provides diagnostic yield and safety similar to those of percutaneous renal biopsy and allows multiorgan biopsy during the same procedure. It can be recommended in patients with percutaneous renal biopsy contraindication or failure.

Adult↗
PubMed2000

Oscillations of exopolymeric composition and sludge volume index in nitrifying flocs.

Protein, carbohydrate, and lipid composition of the exopolymer fraction of a nitrifying sludge in steady-state culture was analyzed after dissociation with 50 mM EDTA and dialysis of the nonfilamentous flocs. Steady-state culture was established when the nitrification rate was constant. The nitrification efficiency at that regime was 93%, also constant. In steady state the concentration of exopolymer protein in the nitrifying sludge floc oscillated from 5 (lowest) to 45 (highest) mg/L with a consistent oscillating pattern having a duration period of 10 d each. Carbohydrate and lipid content in the flocs showed no significant variations (30 and 36 mg/L, respectively). Only 20% of the extracellular polysaccharides had molecular weights higher than 10 kDa, suggesting that the floc aggregation depended on smaller fractions of low-molecular-weight carbohydrates. The oscillations in the concentration of exopolymeric protein coincided with parallel variations in the sludge volumetric index (SVI) value (12.2+/-2.1 mL/g). Analysis of the polymeric substances of the floc and suspended solids corroborated by statistical analysis indicated that the variations in the SVI of the nitrifying nonfilamentous flocs were mainly related to the changes in the exopolymeric protein content.

Biodegradation, Environmental↗
PubMed2000

Human chorionic gonadotropin and intravaginal natural progesterone are equally effective for luteal phase support in IVF.

This prospective randomized study compared human chorionic gonadotropin (hCG) and micronized transvaginal progesterone for luteal support in 310 in vitro fertilization (IVF) patients treated with leuprolide acetate and gonadotropins in a long protocol, and showing normal ovarian response. Both treatment groups were homogeneous for age, BMI, stimulation treatment and ovarian response. Pregnancy rates per embryo transfer were not significantly different (33.1% for the hCG group versus 38.7% for the progesterone group). For IVF patients with a normal response to stimulation under pituitary suppression, the use of hCG or progesterone for luteal support does not seem to have any effect on pregnancy rate. The choice of luteal treatment must balance medical hazard and patient convenience, as both therapeutic regimens seem equally effective.

Administration, Intravaginal↗
PubMed2000

Antimicrobial resistance in Streptococcus pneumoniae: implications for patients with community-acquired pneumonia.

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. During the past decade, the prevalence of penicillin resistance in S pneumoniae has increased dramatically, with resistance rates approaching 45% in some areas of the United States. Streptococcus pneumoniae has also acquired resistance to other commonly used antimicrobials, including cephalosporins, macrolides, and trimethoprim-sulfamethoxazole. While vancomycin and the newer quinolones are currently highly active against most strains of S pneumoniae, reduced susceptibilities to these agents have been identified in some strains. Prior use of antimicrobial agents is the major risk factor for colonization and infection with antibiotic-resistant strains. beta-Lactam antibiotics remain the treatment of choice for infections caused by susceptible S pneumoniae. The optimum therapy for penicillin-resistant strains remains unclear. Appropriate empirical therapy for patients with community-acquired pneumonia depends in part on the community-specific resistance patterns of S pneumoniae to various antibiotics. In this article, we provide an overview of the development of S pneumoniae resistance to commonly used antibiotics and discuss the implications of the development of resistance on treatment decisions.

Anti-Bacterial Agents↗
PubMed2000

Hematologic and serum chemistry values of the captive European wildcat.

Hematologic and serum chemistry values were determined for 20 adult captive European wildcats (Felis silvestris) in Lleida (Catalonia, Spain). Seven wildcats (4 females and 3 males) were captured in the wild and 13 (4 females and 9 males) were born and raised in captivity. Samples were collected between September and December from 1993 to 1998. Blood was obtained by jugular venipuncture after administration of either ketamine and xylazine or ketamine and medetomidine. Females had significantly higher mean eosinophil counts, albumin concentration, (and A/G ratio) and lower mature neutrophil counts, although these differences were not clinically relevant. Results for many of the blood parameters fall within the reference range for domestic cats. Mean values for alanine aminotransferase, aspartate aminotransferase, creatine phosphokinase, and lactate dehydrogenase activities as well as blood urea nitrogen, glucose, and sodium concentrations were higher than the upper limit of the reference range for domestic cats.

Animals↗
PubMed2000

Retroperitoneal fibrosis and membranous nephropathy.

We report on a patient with a past history of Pott's abscess who suffered both from a retroperitoneal fibrosis and a membranous glomerulonephritis. Five cases of retroperitoneal fibrosis and immune complex glomerulonephritis are already reported in the literature. These associations might result from a particular systemic immune response to an unknown antigen. Consequently, we consider the role of tuberculosis in our case.

Adult↗
PubMed2000

Providing progesterone for pregnancy: control of cholesterol flux to the side-chain cleavage system.

Progesterone, which is required to support human gestation, is derived initially from the corpus luteum and subsequently from the placenta. The rate-limiting step in progesterone synthesis is the delivery of cholesterol to the mitochondrial cholesterol side-chain cleavage system. The steroidogenic acute regulatory protein (StAR) mediates this process in the corpus luteum, whereas in the placenta, which does not express StAR, a StAR homologue, MLN64, may accomplish this function. StAR expression is regulated in the ovary at the transcriptional level by a cAMP-activated signal transduction system and StAR activity is also increased acutely by protein kinase A-mediated phosphorylation. These long-term (transcriptional) and short-term (post-translational, that is, phosphorylation) mechanisms govern luteal steroidogenic activity. The StAR protein has two key functional domains. The StAR C-terminal domain increases cholesterol movement to cytochrome P450scc by promoting sterol desorption from the sterol-rich outer mitochondrial membrane, driving it to the relatively sterol-poor inner membrane. The N-terminal domain mitochondrial targeting sequence directs the StAR protein to the mitochondria.

Carrier Proteins↗
PubMed1999

Stimulation of tyrosine phosphorylation by progesterone and its 11-OH derivatives: dissection of a Ca(2+)-dependent and a Ca(2+)-independent mechanism.

Progesterone has previously been shown to exert non-genomic effects on human spermatozoa by opening plasma membrane ion channels and by stimulating protein tyrosine phosphorylation. Here we examined how these two activities are influenced by 11-hydroxyl substitution of the steroid molecule either in the alpha- or in the beta-configuration. Both the 11alpha-OH and the 11beta-OH derivatives of progesterone were more effective than progesterone in stimulating tyrosine phosphorylation, although 11alpha-OH-progesterone was a markedly weaker Ca(2+)-influx inducing agonist than the other two steroids. In Ca(2+)-containing medium, the agonist activity of the 11alpha-OH derivative was weaker than that of the 11beta-OH derivative, and it was completely abolished by genistein, whereas that of progesterone and its 11beta-OH derivative was inhibited only partly by this drug. In contrast, when applied in Ca(2+)-free medium, the 11alpha-OH derivative was the strongest of the three agonists tested, and the effects of all the three steroids were completely abolished by genistein. These data show that the structural motifs of steroid molecules that are responsible for the stimulation of tyrosine phosphorylation are different from those mediating the steroid action on Ca2+ influx through plasma membrane channels. The synthesis of selective agonists of both activities may lead to the development of new pharmacological agents to be used in the treatment of steroid-dependent pathologies.

Calcium↗
PubMed1999

Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.

BACKGROUND: Little is known about the prevalence of atopic eczema outside Northern Europe. OBJECTIVES: We sought to describe the magnitude and variation in the prevalence of atopic eczema symptoms throughout the world. METHODS: A cross-sectional questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries throughout the world. Those children with a positive response to being questioned about the presence of an itchy relapsing skin rash in the last 12 months that had affected their skin creases were considered to have atopic eczema. Children whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. RESULTS: Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 years in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Iran to over 16% in Japan and Sweden in the 6 to 7 year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Higher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Central Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. CONCLUSIONS: Atopic eczema is a common health problem for children and adolescents throughout the world. Symptoms of atopic eczema exhibit wide variations in prevalence both within and between countries inhabited by similar ethnic groups, suggesting that environmental factors may be critical in determining disease expression. Studies that include objective skin examinations are required to confirm these findings.

Adolescent↗
PubMed1999

Presence of two enzymes, different from the F1F0-ATPase, hydrolyzing nucleotides in human term placental mitochondria.

The hydrolysis of ATP, ADP or GTP was characterized in mitochondria and submitochondrial particles since a tightly-bound ATPase associated with the inner mitochondrial membrane from the human placenta has been described. Submitochondrial particles, which are basically inner membranes, were used to define the location of this enzyme. Mitochondria treated with trypsin and specific inhibitors were also used. The oxygen consumption stimulated by ATP or ADP was 100% inhibited in intact mitochondria by low concentrations of oligomycin (0.5 microgram/mg) or venturicidine (0.1 microgram/mg), while the hydrolysis of ATP or ADP was insensitive to higher concentrations of these inhibitors but it was inhibited by vanadate. Oligomycin or venturicidine showed a different inhibition pattern in intact mitochondria in relation to the hydrolysis of ATP, ADP or GTP. When submitochondrial particles were isolated from mitochondria incubated with oligomycin or venturicidine, no further inhibition of the nucleotide hydrolysis was observed, contrasting with the partial inhibition observed in the control. By incubating the placental mitochondria with trypsin, a large fraction of the hydrolysis of nucleotides was eliminated. In submitochondrial particles obtained from mitochondria treated with trypsin or trypsin plus oligomycin, the hydrolysis of ATP was 100% sensitive to oligomycin at low concentrations, resembling the oxygen consumption; however, this preparation still showed some ADP hydrolysis. Native gel electrophoresis showed two bands hydrolyzing ADP, suggesting at least two enzymes involved in the hydrolysis of nucleotides, besides the F1F0-ATPase. It is concluded that human placental mitochondria possesses ADPase and ATP-diphosphohydrolase activities (247).

Adenosine Triphosphate↗
PubMed1999

Prevention of graft-versus-host disease in high risk patients by depletion of CD4+ and reduction of CD8+ lymphocytes in the marrow graft.

From March 1994 to September 1997, 30 patients with hematological malignancies (12 ANLL, 10 CML, four ALL and four multiple myeloma) received HLA-identical allogeneic bone marrow transplants with the marrow graft selectively depleted of CD4+ lymphocytes and the CD8+ cell content adjusted to 1x10(6)/kg. Total depletion of CD4+ and partial depletion of CD8+ lymphocytes was carried out by an immunomagnetical method. All patients were considered as having high risk for developing GVHD by at least one of the following criteria: patient age >35 years; donor age >35 years; donor multiparity or marrow from an unrelated donor. Twenty-four cases received marrow from an identical sibling and six from an unrelated donor. In order to assess the role of methotrexate (MTX) in addition to cyclosporin A (CsA) after transplant, patients were randomly assigned to received either CsA alone (n = 15) or CsA plus a short course of MTX (n = 15). No case of primary graft failure was observed, but two patients developed late graft failure. Six patients presented grade II acute GVHD and no case of severe III-IV GVHD was seen. The actuarial probability of developing grade II-IV acute GVHD was 25.9+/-9.6% for the entire population. Patients receiving post-transplant CsA + MTX had significantly less probability of acute GVHD than those receiving CsA exclusively (6.7+/-6.4% vs. 50.5+/-17.8%, P = 0.03) and the schedule of post-transplant immunosuppression was the only factor associated with the incidence of acute GVHD in a multivariate analysis. The actuarial incidence of chronic GVHD for the entire population was 31.8+/-12.5, and there was no significant difference between both groups with additional prophylaxis. Four patients with CML and three with ANLL relapsed: the actuarial probability of remaining in complete remission for all patients was 53.6+/-17.3%. For patients with acute leukemia, the probability of remaining in complete remission did not differ significantly between those transplanted in first complete remission and those receiving a transplant in more advanced phases of the disease (87.5+/-11.6% vs. 72.9+/-16.5%; P = 0.44). The incidence of mixed chimerism assessed by PCR was 34%. Nineteen patients are alive between 2 and 43 months post-transplant, the probability of overall survival being 57.8+/-10.4%. Our data indicate that this method of selective T cell depletion is very effective in preventing acute GVHD in high risk patients, particularly when used in combination with post-transplant CsA + MTX.

Adolescent↗
PubMed1999

Allogeneic bone marrow transplantation vs chemotherapy for the treatment of childhood acute lymphoblastic leukaemia in second complete remission (revisited 10 years on).

In 1989 we carried out a trial comparing allogeneic BMT to chemotherapy (CT) in 76 children with relapsed acute lymphoblastic leukaemia (ALL). Ten years on we have clinically revised outcome to firmly establish the role of each treatment, to analyse the importance of length of first remission and to provide long-term actuarial results for disease-free survival (DFS) and relapse rate in each group. For 21 patients within the transplantation group, probability of DFS and relapse are 42.8 +/- 10.8% and 40.2 +/- 11.7% (s.e.), respectively. In the chemotherapy group, probability of DFS is 10.0 +/- 4.74% (P = 0.001) and probability of relapse 87.5 +/- 5.2% (P = 0.0004). These results strongly reflect those at initial analysis, confirming a key role of BMT in the management of ALL in second remission. Moreover, on univariate analysis only two factors influenced DFS: treatment group and length of first complete remission (less or more than 30 months from first CR). Thus, it seems clear that the best therapeutic option in early relapse is BMT, whereas DFS in late relapse is at the limit of significance (P = 0.07), with a higher relapse rate in the CT group. Although encouraging results using intensified rotational combination chemotherapy have been published, prospective randomised studies are needed to assess with certainty the best therapeutic option in these patients.

Adolescent↗
PubMed1999

On early sensitization to allergens and development of respiratory symptoms.

BACKGROUND: Various studies have suggested that a sequence of events occurring in childhood may affect the development of asthma in susceptible individuals. We have investigated whether early childhood sensitization to aeroallergens is an important risk factor in the later development of asthma symptoms. OBJECTIVE AND METHODS: In this study we examine this issue in children enrolled in the Tucson epidemiology study of obstructive airways disease, who had at least two allergen skin tests, one before and one after 8 years of age. Respiratory symptom data were available from 12 survey questionnaires, spanning a period of 20 years. During the first, sixth, seventh and eleventh surveys, skin tests were performed with commercially available allergens. CONCLUSION: As compared with children who were sensitized after 8 years of age, children over 8 years who were sensitized to any allergen before age 8 years were significantly more likely to report shortness of breath with wheeze (SOBWZ), wheeze apart from colds or wheeze most days (OR = 4.1 SOBWZ; OR = 3.88 WZ apart from colds; and OR = 2.83 WZ most days). Children who were sensitized after 8 years were no more likely to have the symptoms described above than children who were never found to be sensitized. Based on these results we conclude that early allergic sensitization is a significant risk factor for later development of wheezy symptoms, where as late sensitization is not.

Adolescent↗