Biomedical subjects
G Alvarado
Publications and source records attributed to G Alvarado.
Gene introgression into Coffea arabica by way of triploid hybrids (C. arabica x C. canephora).
Interspecific triploid hybrid plants between the tetraploid species Coffea arabica L. and the diploid species C. canephora P. were backcrossed to C. arabica. Although characterised by a low production and an important fruit dropping, all attempted crosses (ie, 6) generated BC(1) progenies. Flow cytometric analysis of the nuclear DNA content revealed that most of the BC1 individuals were nearly tetraploid. Among the male gametes produced by the interspecific triploid hybrids, those presenting a high number of chromosomes appeared strongly favoured. Only pollen mother cells having nearly 22 chromosomes were effective, the others leading to deficient endosperm and fruit dropping. Molecular markers (ie, microsatellite and AFLP) combined with evaluations of morphological characteristics and resistance to leaf rust were applied to verify the occurrence of gene transfer from C. canephora into C. arabica, and to estimate the amount of introgression present in BC(1) individuals. The results reveal a strong deficiency in the C. canephroa alleles indicating a severe counter-selection against the introgression of genetic material from C. canephora into C. arabica by way of triploid hybrids. However, introgressants displaying desirable traits such as a high resistance to leaf rust were obtained. The low level of introgression could be an advantage by facilitating the recovery of the recurrent parent and possibly reducing the number of required backcrosses. On the other hand, this could be a limitation when attempting the transfer of a complex trait or several simply inherited traits.
Acceptability of two spermicides in five countries.
Data from a large, international, multicenter, randomized trial were analyzed to compare the acceptability of two nonoxynol-9 spermicide preparations. Women who wished to use a spermicide for contraception were randomly assigned to use either a foaming tablet (n = 383) or a nonoxynol-9 film (n = 382) for 28 weeks as their only method of contraception. Participants completed questionnaires about acceptability of the assigned product 4 weeks after admission and at discontinuation. Women in both groups had very favorable opinions of the spermicide. The proportion of women who said that they liked their assigned product very much was 50% in the tablet group and 55% in the film group. Significantly more women in the film group rated the spermicide difficult to insert and stated that the product stuck to the finger during insertion. More women in the tablet group said that the product was messy and that, at least once, it did not dissolve. In both groups, liking the product was significantly associated with consistency of use, but not with subsequent pregnancy. Participants' male partners had little influence on participants' opinions about, or use of, the spermicides. Although previous analyses showed that both spermicides are associated with high pregnancy rates, they are both highly acceptable to most women.
Identifying condom users at risk for breakage and slippage: findings from three international sites.
OBJECTIVES: This study examined whether past condom failure (breakage, slippage, or both) can predict future failure and evaluated other predictors of condom failure. METHODS: At each of 3 international sites, approximately 130 male condom users were enrolled and given 5 condoms to use for vaginal intercourse over a 3-week period. RESULTS: Men at increased risk (history of 1 or more condoms that broke or slipped off) reported approximately twice as many condom failures as those not in this group. Condom failure increased with the number of adverse condom use behaviors reported per participant. Opening condom packages with sharp objects and unrolling condoms before donning were associated with breakage. Unrolling condoms before donning and lengthy or intense intercourse were associated with slippage. Of background characteristics evaluated, having less education was associated with condom failure. CONCLUSIONS: These data suggest that a history of condom failure predicts future failure, a finding that may be useful for targeted intervention. Moreover, these data provide further evidence that certain behaviors and lower educational attainment are associated with condom failure.
A multicenter comparative study on the efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant and Norplant-II.
In order to assess efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant and Norplant-II in Mexican women, a comparative phase III clinical trial was undertaken in eight clinics across the country. The study involved 1052 women who were followed-up trimonthly for three years. Cumulative pregnancy rates were 0.29% and 0.34% for Norplant and Norplant-II implants, respectively. Similar overall cumulative discontinuation rates were observed at three years: 50.38% for Norplant capsules, and 50.44% for Norplant-II rods. The main method-related reason for termination was endometrial bleeding irregularity which led to discontinuation rates of 11.94% and 11.62% for Norplant and Norplant-II contraceptive systems, respectively. In 15,279 woman-months of experience accumulated with Norplant implants and 14,092 with Norplant-II implants, there were few adverse events reported. No difference was found between the two groups in either difficulty for implants placement and removal or women's discomfort, even though the time required for insertion and removal of Norplant capsules was longer than for Norplant-II rods. It is concluded that during the first three years of use, both implants systems are equally effective, safe, and acceptable.
Is the copper T 380A device associated with an increased risk of removal due to bleeding and/or pain? An analysis.
Previous studies have consistently shown that the family of the Copper T 380 devices is more effective in preventing accidental pregnancies than the inert, as well as most other, if not all, copper devices. However, a number of these studies also reported a higher removal rate due to bleeding and/or pain for the TCu 380A than for other devices. The programmatical importance of these findings prompted us to analyze the international multi-center randomized clinical trial datasets to examine this question on the new TCu 380A (ParaGard) recently marketed in the U.S. Our results, while confirming the inherent superior efficacy of the TCu 380A, did not reveal a significantly higher removal rate because of bleeding and/or pain among TCu 380A users than among users of the comparative devices, which included the Lippes Loop D, the TCu 200, the TCu 220 and the Multiload Cu 250 devices.
Estrogen-progestogen once-a-month injectable contraceptives and serum prolactin.
To assess the effect of hormonal monthly injectable contraceptives upon the serum values of immunoreactive prolactin (Prl), three groups of women of reproductive age exposed to different estrogen-progestogen injectable formulation for a minimum of one year were studied. The first group (n = 10) received dihydroxyprogesterone acetophenide 150 mg and estradiol enanthate 10 mg (DHPA/E2-EN), Group 2 (n = 21) received medroxyprogesterone acetate 25 mg and estradiol cypionate 5 mg (MPA/E2-C) and Group 3 (n = 19) was exposed to norethisterone enanthate 50 mg and estradiol valerate 5 mg (NET-EN/E2-V). A group of IUD users (n = 16) served as the control group. Serum Prl and 17 beta-estradiol (E2) concentration were determined in blood samples (0 and 15 min.) on days 0 (day of last injection), 10, 20 and 30 after last contraceptive injection. The results demonstrated a slight though not significant increase (p greater than 0.05) in serum Prl in the three experimental groups as compared with the IUD control group. This increase in Prl levels observed on day 10 post-last injection never exceeded the upper limits of the normal range (20 ng/ml). Overall, the data demonstrated that the chronic administration of these estrogen/progestogen once-a-month injectable contraceptives does not affect the Prl baseline secretion in women.
[The characteristics of the menstrual bleeding pattern in a group of normal women from Durango].
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Norethisterone contraceptive microspheres.
Two formulations of polylactic and polyglycolic acid microcapsules containing 75 and 100 mg of NET respectively were studied for a 90-day period of anticipated contraceptive effect in two groups of five women. A 200 mg dose of NET preparation was also studied for a 180-day period of anticipated contraceptive effect in 19 women. Alteration in menstrual cycle, with tendency to short bleeding episodes, spotting days, and amenorrhea were the most important collateral effects. In the majority of cases, ovulation was inhibited. No cases of pregnancy were presented. The obtained NET circulating levels were very stable during the period of anticipated contraceptive effect.
[Studies on cooperation-enhancing approach in dealing with children in the dental setting. 1. A detailed record of children's emotional and behavioral reactions in dental settings].
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The value of image post-processing in sonomammography: a preliminary report.
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[Early mechanical respiration with prolonged inspiration in the treatment of acute respiratory insufficiency in the newborn].
The experience at the Servicio de Medicina Perinatal Pediátrica of the Centro Hospitalario "20 de Noviembre" of the ISSSTE is reported on the application of a ventilatory assistance criterion to treat the severe respiratory distress syndrome in the newborn. Early application of intermittent mechanical ventilation (IMV) is established to avoid clinical impairment. The mechanical ventilator is used in such a way that without withdrawing therapeutic effectiveness, it may cut down to a minimum complications derived from the use of IMV. The results show increase in survivorship, specially among the lower weight population and less complications than with the previous management method, in spite of a 70% increase in the use of IMV.