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J Diaz

Publications and source records attributed to J Diaz.

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

Return of fertility after discontinuation of the once-a-month injectable contraceptive Cyclofem.

The objective of this study was to evaluate the return of fertility in women who used Cyclofem as a contraceptive method during the introductory studies conducted in Brazil, Chile, Colombia, and Peru. From these four cohorts, 101 women were eligible for the study. Thirty-one were not included in the study either because they refused to be interviewed, had initiated another contraceptive method the month after discontinuation, or were unable to be contacted. A total of 70 women were included in the study. Our results showed that the return to fertility rate after the discontinuation of Cyclofem was 1.4 per 100 women at the end of the first month and reached 82.9 at one year. More than 50% were pregnant at 6 months. Fifty-one (94.4%) pregnancies ended in a live birth, two were spontaneous first trimester abortions, and one was a hydatidiform mole. Return of fertility was not related to the woman's age at the time of discontinuation, her weight, or the number of Cyclofem injections. In conclusion, fertility is restored by 1 month following Cyclofem discontinuation. Users and potential users should be counseled regarding the rapid return of fertility after discontinuing this method of contraception.

Adult↗
PubMed1997

Introductory study of the once-a-month, injectable contraceptive Cyclofem in Brazil, Chile, Colombia, and Peru.

An introductory trial with the injectable contraceptive Cyclofem was carried out in Brazil, Chile, Colombia, and Peru, with participation by 3,183 women. Women were followed-up for up to 2 years of use and the data were evaluated by life table analysis. A total of 29,676 women-months were accumulated for up to 2 years. No pregnancies were observed in the 2 years. The discontinuation rates for amenorrhea in the first year ranged from 3.4 in Brazil to 8.1 in Colombia, and for menstrual disturbances from 5.1 in Chile to 9.2 in Brazil. The discontinuation rates for other medical reasons ranged from 7.8 in Brazil to 26.3 in Colombia, and for personal reasons from 17.2 in Chile to 23.5 in Brazil. Continuation rates ranged from 42.3 in Colombia to 52 in Chile. In the second year of observation the rates of discontinuation were lower than those observed in the first year, with the exception of personal reasons in Brazil, which were the same as those observed in the first year. Continuation rates ranged from 19.4 in Brazil to 36.8 in Chile. The comparison of reasons for discontinuation in selected clinics showed that the rate for amenorrhea in one clinic in Chile was more than three times that in others and in Peru was seven times more in one clinic than in another. Regarding menstrual disturbances, in Peru one clinic presented a rate three times higher than the others. The main reasons for discontinuation due to other medical reasons were headache and weight gain. In conclusion, Cyclofem presented a high contraceptive efficacy and an acceptable rate of continuation and discontinuation for up to 2 years in the four countries.

Adult↗
PubMed1997

nNOS and Ca2+ influx in rat pancreatic acinar and submandibular salivary gland cells.

Regulation of agonist-activated Ca2+ influx by the NOS pathway through generation of cGMP is being found in an increasing number of cell types. In the present work, we examined the role of the NOS pathway in agonist-evoked [Ca2+]i oscillations and attempted to identify the NOS isoform most likely to regulate Ca2+ influx. For this, we first show that two Ca(2+)-mobilizing agonists acting on pancreatic acinar cells, bombesin (BS) and the cholecystokinin analog CCK-JMV-180 (CCKJ), evokes different type of [Ca2+]i oscillations. The BS-evoked [Ca2+]i oscillations rapidly became acutely dependent on the presence of extracellular Ca2+, whereas the CCKJ-evoked oscillations continue for long periods of time in the absence of Ca2+ influx. This differential behavior allowed us to isolate Ca2+ influx and study its regulation while controlling for non specific effects on all other Ca2+ transporting events involved in generating [Ca2+]i oscillations. Inhibitors of selective steps in the NOS pathway inhibited agonist-induced cGMP production. The inhibitors were then used to show that scavenging NO with reduced hemoglobin, inhibition of guanylyl cyclase with 1H-[1,2,4] oxadiazolo[4,3-a] quinoxaline-1-one (ODQ) and inhibition of protein kinase G with Rp-8-pCPT-cGMPS inhibited [Ca2+]i oscillations evoked by BS but not those evoked by CCKJ. These findings were extended to duct and acinar cells of the SMG. In these cells, Ca(2+)-mobilizing agonists stimulate large Ca2+ influx, which was inhibited by all inhibitors of the NOS pathway. Western blot analysis and immunolocalization revealed that the cells did not express iNOS, eNOS was expressed only in blood vessels and capillaries whereas nNOS was expressed at high levels next to the plasma membrane of all cells. Accordingly, the nNOS inhibitor 7-nitroindazole (7-NI) inhibited BS- but not CCKJ-evoked [Ca2+]i oscillations and Ca2+ influx into SMG acinar and duct cells. Thus, together, our findings favor nNOS as the isoform activated by the Ca2+ released from internal stores to generate cGMP and regulate Ca2+ influx.

Animals↗
PubMed1997

Effect of Anapsos (Polypodium leucotomos extract) on in vitro production of cytokines.

AIMS: The aim of the study was to test the immunomodulating capacity of Anapsos, Polypodium leucotomos extract, in vitro in an attempt to explore how this extract acts from an immunological point of view and thus to identify a common link capable of explaining most of its effects. METHODS: Polypodium leucotomos rhizomes were harvested in Guatemala and the extract, Anapsos, obtained. Mononuclear cells were obtained by density gradient centrifugation from healthy donors, and stimulated with phytohemagglutinin or Pokeweed with and without Anapsos and with Anapsos alone. Cell proliferation was determined by thymidine incorporation. Cells were also stimulated and the following cytokines determined by ELISA at 0, 12, 24, 48, 72, and 96 h: IL-1 beta, TNF-alpha, IL-2, INF-8, IL-4 and IL-10. RESULTS: Anapsos, Polypodium leucotomos extract, has a modulating effect on the in vitro production and release of cytokines by peripheral blood mononuclear cells of healthy subjects. At doses effective in vivo, Anapsos can stimulate PBMNc proliferation, delay IL-1 beta secretion and at the same time increase that of IL-2, IL-10, and INF-gamma. CONCLUSIONS: Anapsos may have an antagonistic effect on some of the cytokines released on cell stimulation with LPS and/or PHA, which suggests that this product has a pleiotropic effect on different populations in the immune system.

Adult↗
PubMed1997

Urea inhibits Na-K-2Cl cotransport in medullary thick ascending limb cells.

We examined the effect of physiological concentrations of urea (100-500 mM) on Na-K-2Cl cotransport in cultured cells from mouse medullary thick ascending limb (mTAL). Urea acutely inhibited bumetanide-sensitive K influx in mTAL cells in a concentration-dependent fashion, with a statistically significant inhibition (19%) at 100 mM and 86% inhibition at 500 mM. The effect of urea was entirely reversible and was blocked by prior treatment with okadaic acid, a phosphatase inhibitor, suggesting that urea exerts its action upstream of the phosphorylation-dephosphorylation step. Cell volume was unchanged in the presence of 500 mM urea. The number of [3H]bumetanide binding sites, a measure of the number of functioning cotransporter sites, was decreased in the presence of urea, and the decrease in bumetanide binding was proportional to the decrease in bumetanide-sensitive K influx. Urea also stimulated the Ba-sensitive swelling-activated K efflux from mTAL cells. Thus urea, in concentrations that prevail in the renal medulla, alters ion transport in mTAL cells.

Animals↗
PubMed1997

Immuno and functional characterization of CFTR in submandibular and pancreatic acinar and duct cells.

Cystic fibrosis results from defective Cl- channel activity mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) gene product. In the gastrointestinal tract this is manifested in abnormal salivary secretion and pancreatic insufficiency. This is generally attributed to defective Cl- transport by the ductal system of the glands. We provide the first immunocytochemical and functional evidence for expression of CFTR protein and Cl- current in rat and mouse submandibular gland (SMG) and pancreatic acinar cells, a site proximal to the ductal system of these secretory glands. Monoclonal and polyclonal antibodies recognizing COOH-terminal epitopes of CFTR show that duct and acinar cells from the two glands express CFTR in the luminal membrane. Specificity of the polyclonal antibody was verified by absence of staining in duct and acinar cells of the SMG of cf-/cf- and delta F/delta F mice. Identification of CFTR in acinar cells was aided by demonstrating coexpression of CFTR and type 3 inositol 1,4,5-trisphosphate receptors in the luminal pole of acini and absence of type 3 inositol 1,4,5-trisphosphate receptors in ducts. Electrophysiological characterization in single SMG duct and acinar cells shows the presence of a protein kinase A-activated, voltage- and time-independent, ohmic Cl- current and absence of repolarization-dependent tail currents, all of which are kinetic properties of the CFTR-dependent Cl- channel. In addition, the channel was activated by the nonhydrolyzable ATP analog 5'-adenylylimidodiphosphate and the benzimidazalone NS-004. Channels activated by all activators were inhibited by glibenclamide and a known inhibitory antiserum [anti-CFTR-(505-511)]. Combined immunologic, functional, and pharmacological evidence allows us to conclude that acinar cells of the SMG and pancreas express functional CFTR-dependent Cl- channels. Because this site is proximal to the duct, modification of activity of this channel in acinar cells is likely to contribute to abnormal salivary secretion and pancreatic insufficiency typical of cystic fibrosis.

Animals↗
PubMed1996

Spacial compartmentalization of Ca2+ signaling complexes in pancreatic acini.

Imaging [Ca2+]i at high temporal resolution and measuring the properties of Ca2+ signaling in streptolysin O (SLO)-permeabilized cells were used to study the spacial organization of signaling complexes. Sequential stimulation of single cells within pancreatic acini with several Ca2+-mobilizing agonists revealed an agonist-specific pattern and propagation rate of Ca2+ waves in the same cells, with CCK8 stimulating the fastest and bombesin the slowest waves. More importantly, each agonist initiated the wave in a different region of the same cell. On the other hand, repetitive stimulation with the same agonist induced Ca2+ waves of the same pattern that were initiated from the same region of the cell. The agonist-specific Ca2+ signaling does not appear to be the result of coupling to different G proteins as infusion of an anti-Galphaq antibody into the cells through a patch pipette equally inhibited Ca2+ signaling by all agonists. Further evidence for compartmentalization of signaling complexes was developed in permeabilized cells. The time-dependent loss of Ca2+ signaling due to SLO permeabilization occurred in an agonist-specific manner in the sequence cabachol > bombesin > cholecystokinin. Signaling by all agonists could be completely restored with as low as 2 micro guanosine 5'-3-O-(thio)triphosphate (GTPgammaS). At this low concentration GTPgammaS recoupled inositol 1,4,5-trisphosphate production and Ca2+ release, rather than enhancing phospholipase C activity. Priming of Ca2+ signaling by GTPgammaS was agonist-specific. Guanosine 5'-O-(thio)diphosphate (GDPbetaS) uncoupled the ability of signaling complexes to release Ca2+ much better than stimulating inositol 1,4,5-trisphosphate production. The uncoupling of Ca2+ signaling by GDPbetaS was also agonist-specific. The combined findings of agonist-specific initiation sites of the Ca2+ wave and differential access of guanine nucleotides to signaling complexes suggest spacial compartmentalization of Ca2+ signaling complexes. Each complex must include a receptor, G protein, and phospholipase C that are coupled to a specific portion of the Ca2+ pool.

Acetylcholine↗
PubMed1996

Serum ionized magnesium monitoring during orthotopic liver transplantation.

During orthotopic liver transplantation (OLT) citrate accumulates and magnesium can be chelated, which can lead to ionized hypomagnesemia and cardiovascular dysfunction. Our aim was to study the serum ionized magnesium (Me2+) evolution and establish its relation to serum total Mg and citrate levels during OLT. We studied 58 adult patients undergoing OLT. The serum Me2+ level dropped significantly at the end of the preanhepatic phase, and remained low until the end of the procedure. Furthermore, the Me2+ levels remained below the range of reference from the beginning of the anhepatic phase onward. There was an inverse correlation between Me2+ and citrate for all patients. Me2+, like ionized calcium (Ca2+), is chelated by citrate and its evolution is a mirror image of that of citrate. In our patients, we did not observe any significant dysrhythmias that could be directly attributed to ionized hypomagnesemia. In conclusion, low preoperative levels, together with the massive transfusion of blood products and the increase in renal losses, cause progressive ionized hypomagnesemia in OLT patients. We propose that it he routinely monitored and treated accordingly, as is already done with Ca2+.

Adolescent↗
PubMed1996

Characterization, localization and axial distribution of Ca2+ signalling receptors in the rat submandibular salivary gland ducts.

1. To characterize [Ca2+]i signalling in salivary duct cells a procedure was developed for the rapid preparation and isolation of intralobular ducts, some of which had attached intercalated ducts. The isolated ducts retained agonist-induced Ca2+ signalling after permeabilization with streptolysin O (SLO). 2. The improved cell preparation technique was reflected in the repertoire and intensity of agonist responsiveness of the cells. Measurements of [Ca2+]i in intact cells showed that all agonists previously reported to affect electrolyte transport by the submandibular salivary gland (adrenaline, carbachol, isoprenaline and forskolin) mobilized Ca2+ from internal stores and increased Ca2+ influx across the plasma membrane. 3. The use of the SLO-permeabilized ducts showed that all agonists, including isoprenaline and forskolin, mobilized Ca2+ exclusively from the inositol 1,4,5 trisphosphate (IP3)-sensitive pool. However, in granular ducts only adrenaline mobilized the entire IP3-sensitive pool whereas all other agonists mobilized only part of the pool. 4. All regions of the duct responded to substance P and the luminally secreted agonist ATP. Interestingly, the intercalated duct was most responsive to ATP and demonstrated only a minimal response to all other agonists. The granular region of the same duct and the extralobular duct always responded best to stimulation by adrenaline. 5. The perfused extralobular duct was used to show that adrenaline and carbachol stimulated the duct through the basolateral membrane whereas the receptors for ATP were localized in the luminal membrane of the duct. This suggests the presence of an ATP-dependent positive feedback loop in salivary duct with decreased activity along the ductal tree.

Adrenergic alpha-Antagonists↗
PubMed1996

Bleeding complaints during the first year of norplant implants use and their impact on removal rate.

The frequency of bleeding complaints during the first year of use and their influence on removal rate were analyzed in a retrospective cohort study of 491 Norplant implants acceptors. Removal rates were significantly higher in women having menstrual complaints (1.98% and 29.23% in the first and fourth trimester) than in those who did not mention them (0.79 and 5.07% in the same periods). In all periods of observation, most women who mentioned menstrual problems decided to continue using the method. Two possible explanations for this are that 1) the complaints did not persist for very long, and 2) the most frequent complaint mentioned was bleeding irregularity, which was not as strongly associated with removals as increased or decreased bleeding. The authors conclude that bleeding problems are the most important factor limiting the acceptability of Norplant implants, either being the main reason for removal (3.9 per 100 women) or influencing the rate of removal for other reasons. Adequate counseling appears to be critical for reducing the impact of bleeding problems on removal rates, and thereby increasing the acceptability of the method. The importance of research aimed at preventing or treating menstrual problems to improve the acceptability of the method is emphasized.

Adult↗
PubMed1996

Factors influencing physicians' prescribing behaviour in the treatment of childhood diarrhoea: knowledge may not be the clue.

Proper diarrhoea treatment has received greater attention during the last 10 years. However, the unjustified use of medicines to treat simple episodes of acute diarrhoea continues to divert attention and available resources away from appropriate treatment. A study to identify the factors determining prescribing practices for diarrhoea treatment was carried out in a peri-urban part of Lima, Peru in 1991. Physicians were interviewed, and then their practice was assessed by visits of confederates with healthy children described as ill, by interviews with mothers of sick children leaving the clinic, or by both of these methods. Physicians' reported practices in treating diarrhoea cases were compared to their actual practices. Although physicians' knowledge of drug management seemed to influence the low frequency of prescription of antidiarrhoeal drugs, it did not have the same influence on prescription of antimicrobials. Our results suggest that the diagnostic process and consequently the treatment decision do not follow a scientific rationale for this illness. The physicians' prescribing practices seemed to be more related to agreement with social expectations and the caretakers' perception of the physicians' role than they were to the standard biomedical rules of diarrhoea management.

Advertising↗
PubMed1996

The use of vaginal ultrasound to identify copper T IUDs at high risk of expulsion.

A total of 235 women who had a TCu 380A IUD inserted had a vaginal ultrasound scan performed to identify if the IUDs were correctly placed in the uterine fundus. Women identified as having a misplaced IUD had it removed. The remaining women were compared to 201 women who had an IUD inserted and had no ultrasound evaluation, matched by age and parity. Women were followed-up for one year. Gross cumulative discontinuation rates and continuation rates were calculated by life table analysis. Comparison between groups was done by the Gehan test. The study group had 34 IUDs removed because they were misplaced according to the established criteria. The expulsion rate was significantly higher in the control group, also influencing the continuation rate which was lower in the same group. Of the 34 women who had their IUD removed because it was not correctly placed, only 22 requested and had another IUD inserted. The removal of IUD determined by an ultrasound to be incorrectly placed significantly decreased expulsion rates. However, many IUDs may have been removed unnecessarily, probably resulting in many women not returning to the clinic or deciding to use another contraceptive method.

Adult↗
PubMed1996

Pharmacodynamics and pharmacokinetics of cisatracurium in geriatric surgical patients.

BACKGROUND: Cisatracurium, one of ten stereoisomers that comprise atracurium, is more potent than atracurium and has less propensity to release histamine. This study compares the pharmacokinetics and pharmacodynamics of cisatracurium in elderly and young patients. METHODS: Twelve elderly (aged 65-82 yr) and 12 younger patients (aged 30-49 yr) were anesthetized with nitrous oxide, fentanyl, and isoflurane (0.7%, end-tidal). The mechanomyographic response to train-of-four stimulation was assessed every 15 s after the administration of cisatracurium (0.1 mg/kg). Arterial samples were obtained over 6 h. Plasma cisatracurium concentration versus time data were fit to compartmental models. Pharmacokinetic parameters were determined assuming that elimination occurred from the central compartment only. This provides accurate clearance and half-life estimates but underestimates V(ss) (reported herein as V(ss). The pharmacodynamic response was described by the neuromuscular blocking profile. RESULTS: Onset to 90% paralysis (mean +/- SD) was delayed in the elderly (3.4 +/- 1.0 vs. 2.5 +/- 0.6 min). Recovery profiles were the same for both groups. Elimination half-life was minimally prolonged in the elderly (25.5 +/- 3.7 vs. 21.5 +/- 2.4 min). The Vss was larger in the elderly (126 +/- 16 vs. 108 +/- 13 ml/kg), although the clearances were the same for the two groups (5.0 +/- 0.9 vs. 4.6 +/- 0.8 ml.kg(-1).min(-1). CONCLUSIONS: There are minor differences in the pharmacokinetics of cisatracurium between elderly and young patients. These differences are not associated with changes in recovery profile after a single bolus dose, although the mean time to onset was approximately 1 min longer in elderly patients.

Adult↗
PubMed1996

Consequences of electroencephalographic-suppressive doses of propofol in conjunction with deep hypothermic circulatory arrest.

BACKGROUND: Some patients who undergo cerebral aneurysm surgery require cardiopulmonary bypass and deep hypothermic circulatory arrest. During bypass, these patients often are given large doses of a supplemental anesthetic agent in the hope that additional cerebral protection will be provided. Pharmacologic brain protection, however, has been associated with undesirable side effects. These side effects were evaluated in patients who received large doses of propofol. METHODS: Thirteen neurosurgical patients underwent cardiopulmonary bypass and deep hypothermic circulatory arrest to facilitate clip application to a giant or otherwise high-risk cerebral aneurysm. Electroencephalographic burst suppression was established before bypass with an infusion of propofol, and the infusion was continued until the end of surgery. Hemodynamic and echocardiographic measurements were made before and during the prebypass propofol infusion and again after bypass. Emergence time also was determined. RESULTS: Prebypass propofol at 243 +/- 57 micrograms.kg-1.min-1 decreased vascular resistance from 34 +/- 8 to 27 +/- 8 units without changing heart rate, arterial or filling pressures, cardiac index, stroke volume, or ejection fraction. Propofol blood concentration was 8 +/- 2 micrograms/ml. Myocardial wall motion appeared hyperdynamic at the end of cardiopulmonary bypass, and all patients were weaned therefrom without inotropic support. After bypass, vascular resistance decreased further, and cardiovascular performance was improved compared to baseline values. Nine of the 13 patients emerged from anesthesia and were able to follow commands at 3.1 +/- 1.4 h. Three others had strokes and a fourth had cerebral swelling. CONCLUSIONS: Propofol infused at a rate sufficient to suppress the electroencephalogram does not depress the heart or excessively prolong emergence from anesthesia after cardiopulmonary bypass and deep hypothermic circulatory arrest.

Adolescent↗