Browsing by Author "Perez, A"

Now showing 1 - 6 of 6
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    Adverse outcomes of planned and unplanned pregnancies among users of natural family planning: A prospective study
    (1997) Bitto, A; Gray, RH; Simpson, JL; Queenan, JT; Kambic, RT; Perez, A; Mena, P; Barbato, M; Li, CJ; Jennings, V
    Objectives. The purpose of this study was to determine propectively whether unplanned pregnancies are associated with adverse pregnancy outcomes among users of natural family planning.
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    Fertilisation involving ageing gametes, major birth defects, and Down's syndrome
    (2002) Simpson, JL; Gray, R; Perez, A; Mena, P; Queenan, J; Barbato, M; Pardo, F; Kambic, R; Jennings, V
    For many years, ageing of gametes as a result of prolonged retention In the female reproductive tract before fertilisation has been circumstantially associated with major birth defects. To assess this association, we studied pregnant women who had recorded the timing, with regard to presumed ovulation, of the coital event leading to conception. We found major anomalies In 11 l of 400 Infants born to women with optimally timed conceptions (on the day of or 1 day before ovulation), compared with 14 (2.5%) of 538 Infants of women with non-optimally timed conceptions (odds ratio 0.94, 95% CI 0.43-2.06). The numbers of Infants with Down's syndrome were two l of 400, and four (0.7%) of 538, respectively (1.48, 0.27-8.06). There is no association between ageing gametes and major birth defects, Including Down's syndrome.
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    Further evidence that infection is an infrequent cause of first trimester spontaneous abortion
    (1996) Simpson, JL; Gray, RH; Queenan, JT; Barbato, M; Perez, A; Mena, P; Kambic, RT; Pardo, F; Stevenson, W; Li, CJ; Jennings, V
    A previous cohort study found pro clinical evidence that infection occurred more often in subjects experiencing pregnancy loss compared with those experiencing successful pregnancy [Simpson et al. (1996) Hum. Reprod, 11, 668-672]. Given these surprising findings, we conducted a similar analysis on another cohort arise followed prospectively. Using couples practising natural family planning for conception or contraception, information on clinical evidence of infection was gathered beginning with week 5 of gestation. Information on fever and signs of overt infection was specifically sought by interview and physical examination. Frequencies of urinary, vaginal and other infections in subjects experiencing pregnancy loss were 11.1, 9.5 and 8.7% respectively, not significantly different from rates in subjects having liveborns (10.1, 10.2 and 10.3% respectively). Thus, no association between clinical infection and early pregnancy loss (less than or equal to 16 weeks) was observed, Cohere studies utilizing biologically based assays are awaited because extant data do not provide evidence that clinically evident infections play major roles in first trimester pregnancy losses.
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    Glyphosate-resistant Lolium multiflorum in Chilean orchards
    (BLACKWELL PUBLISHING LTD, 2003) Perez, A; Kogan, M
    Lolium multiflorum (Italian ryegrass) seeds suspected of being resistant to glyphosate were collected from fruit orchards at two locations, San Bernardo (SB) and Olivar (OL), Chile, that had been treated an average of three times per year with the isopropylamine salt of glyphosate during the previous 8-10 years. Laboratory experiments were conducted for each orchard population and a susceptible population, a commercial cultivar called Tama (TM), using Petri dishes containing filter paper saturated with 5 mL of glyphosate solution (0-160 mg a.e. L-1 ). Pot dose-response experiments were also conducted in the greenhouse. The three L. multiflorum populations were treated with glyphosate (0.00-4.32 kg a.e. ha(-1) ). The dose needed to reduce shoot length (Petri dish experiment) and fresh weight (pot dose-response experiment) by 50% was determined for each population. Compared with the TM population, the Petri dish experiment found that the SB and OL populations were five- and sixfold, respectively, more resistant to glyphosate, whereas the pot dose-response experiment found that the SB and OL populations were two- and fourfold, respectively, more resistant to glyphosate. These results confirm a new case of glyphosate resistance in a novel species, L. multiflorum , and correspond to the first case of glyphosate resistance reported from South America.
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    Increased aortic NADPH oxidase activity in rats with genetically high angiotensin-converting enzyme levels
    (LIPPINCOTT WILLIAMS & WILKINS, 2005) Jalil, JE; Perez, A; Ocaranza, MP; Bargetto, J; Galaz, A; Lavandero, S
    In humans and rats, angiotensin I-converting enzyme activity is significantly determined by a gene polymorphism. Homozygous Brown Norway rats have higher plasma angiotensin I-converting enzyme activity and circulating angiotensin II (Ang II) levels than Lewis rats. Because Ang II induces NAD(P) H oxidase activation, we hypothesized here that Brown Norway rats have higher vascular NAD(P) H oxidase activity and superoxide anion production than Lewis rats. Homozygous Brown Norway (n = 15) and Lewis (n = 13) male rats were used. Plasma angiotensin I-converting enzyme activity (by fluorimetry), Ang II levels (by high-performance liquid chromatography and radioimmunoassay), and aortic NAD(P) H oxidase activity, as well as superoxide anion production ( by chemiluminescence with lucigenin) were measured. Plasma angiotensin I-converting enzyme activity and Ang II levels were 100% higher in Brown Norway rats than in Lewis rats (P < 0.05). Aortic angiotensin I-converting enzyme, but not Ang II, was elevated (P < 0.05). Aortic superoxide anion production and NAD(P) H oxidase activity were 300% and 260% higher in Brown Norway than in Lewis rats, respectively (P < 0.05), which was not observed in Brown Norway rats treated with candesartan (10 mg/kg per day for 7 days). Endothelial NO synthase activity in the aorta from Brown Norway rats was significantly lower than in Lewis rats. However, inducible NO synthase activity and both endothelial NO synthase and inducible NO synthase mRNA and protein levels were similar in both genotypes. In summary, Brown Norway rats have higher vascular NAD(P) H oxidase activity and superoxide anion production than Lewis rats, suggesting the presence of a higher level of vascular oxidative stress in rats with genetically higher angiotensin I-converting enzyme levels. This effect is mediated through the angiotensin I receptor.
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    The efficacy of the lactational amenorrhea method (LAM) among working women
    (2000) Valdés, V; Labbok, MH; Pugin, E; Perez, A
    The purpose of this study was to assess the efficacy of the lactational amenorrhea method (LAM) for family planning among mothers who are separated from their infants by work. The study population, 170 urban middle class women who planned to return to work before 120 days postpartum, were interviewed monthly for 6 months postpartum and contacted at 12 months. The study population received clinical support for expressing their milk and exclusively breast-milk feeding the infants and for the use of LAM for birth spacing. The cumulative life table pregnancy rate by 6-month was 5.2%, with 3 pregnancies, one at each of months 4, 5, and 6. LAM for working women, as described in this article, might be associated with a higher pregnancy risk than LAM use among non-working women. Therefore, women using LAM should be informed that separation from the infant might increase their risk of pregnancy. (C) 2001 Elsevier Science Inc. All rights reserved.