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Biomedical subjects

A S Lopes

Publications and source records attributed to A S Lopes.

At least 19 recordsLinked to original sources
PubMed2006

Investigation of respiration of individual bovine embryos produced in vivo and in vitro and correlation with viability following transfer.

BACKGROUND: Quantification of oxygen consumption by individual preimplantation embryos has the potential to improve embryo selection. This study investigated whether respiration rates of individual embryos are useful indicators of embryo viability. The effect of the Nanorespirometer on embryo viability was also evaluated. METHODS: The respiration rates of individual day 7 bovine in vivo- (n=44) and in vitro-produced (n=156) embryos were measured using the Nanorespirometer. In vivo-produced embryos were individually transferred to recipients. RESULTS: The respiration rates of in vivo-produced embryos increased with increasing morphological quality and stage of development (P < 0.05). Pregnancy rates on days 35 and 60 were 65 and 60%, respectively. The mean respiration rate did not differ significantly between embryos producing and not producing a pregnancy, but the transfer of embryos with respiration rates <0.78 nl/h, between 0.78 and 1.10 nl/h, and >1.10 nl/h resulted in 48, 100 and 25% pregnancy rate, respectively. The mean respiration rate of in vitro-produced embryos was higher than that of in vivo-produced embryos because of differences in the morphological quality and stage of development. CONCLUSION: The Nanorespirometer does not adversely influence embryo viability, but the sample size was too small to confirm the significance of the correlation observed between respiration rates and viability.

Animals↗
PubMed2006

Relationship of pre-ovulatory follicle size, estradiol concentrations and season to pregnancy outcome in dairy cows.

This study was carried out to evaluate effects of pre-ovulatory follicle size, plasma concentrations of estradiol and progesterone, and season on pregnancy outcomes in dairy cows. Holstein cows (n = 144) were synchronized and inseminated (Ovsynch/TAI protocol) in two distinct periods (cold versus warm season). Blood samples were collected daily from AI (day 0) to day 8 and on days 15, 22, 29, 36 and 64 to measure progesterone and estradiol. Pregnancy diagnosis was performed at days 29, 43 and 64. The pre-ovulatory follicle size was larger and the plasma estradiol concentrations on the day of AI were greater in animals that became pregnant. Plasma progesterone concentrations diverged and became greater after day 5 post-AI, in cows diagnosed pregnant, as compared to non-pregnant cows. The overall pregnancy rate (33%) or late embryonic/early fetal losses (23%) did not differ between seasons, but plasma estradiol concentrations on the day of AI and plasma concentrations of progesterone in pregnant cows were lower in the warm season. Reduced CL function, measured as plasma progesterone concentrations, from days 22 or 29 post-AI onward for cold and warm season, respectively, was associated with subsequent late embryonic/early fetal mortality. Overall, pregnancy was related to diameter of the pre-ovulatory follicle and plasma E2 on the day of AI, but embryonic/fetal losses were not. Season did not affect these outcomes, even though it influenced luteal function after AI.

Abortion, Veterinary↗
PubMed2006

Effect of days post-partum, breed and ovum pick-up scheme on bovine oocyte recovery and embryo development.

The objective of this study was to investigate (i) the effect of two different ovum pick-up (OPU) schemes (once vs twice weekly aspirations) on oocyte recovery rate, quality and subsequent in vitro embryo development, (ii) the influence of days post-partum on oocyte recovery and (iii) possible differences in OPU results from two different herds. In group A, OPU was performed twice weekly in two Holstein Friesian (HF) and three Danish Red and White (DRW) cows from a private herd. In the research herd, two groups of eight HF cows were investigated: group B (OPU once weekly) and group C (OPU twice weekly). The collected oocytes were subsequently submitted to in vitro embryo production. More oocytes were recovered from the private herd when compared with the research herd. In the research herd, the twice weekly scheme aspirated more oocytes than the once weekly scheme. The quality of the retrieved oocytes was significantly different between groups B and C but not between groups A and C, and HF cows yielded higher quality oocytes than DRW cows (p = 0.029). Oocytes from group C showed higher level of embryonic development than group B oocytes. No differences in blastocyst rates were observed between groups A and C. Session affected the number of retrieved oocytes and subsequent developmental rates, with these being lower in the first compared with the last sessions. Finally, there was no significant effect of days post-partum in the number and quality of the retrieved oocytes, likely because of the small group size and high variation between sessions.

Animals↗
PubMed2005

Respiration rates of individual bovine in vitro-produced embryos measured with a novel, non-invasive and highly sensitive microsensor system.

Oxygen consumption is a useful parameter for evaluating embryo quality, since it provides a valuable indication of overall metabolic activity. Over the years, several approaches have been used to measure the respiration rates of individual embryos, but a convincing method has not yet been reported. In this study, we introduce and have validated a novel high resolution microsensor technology to determine the respiration rates of individual embryos at different developmental stages. We have employed this technology to investigate the correlation between respiration rate and embryo morphology, diameter and sex. Following morphological evaluation, individual respiration rates of day 3 (n = 18) and day 7 (n = 60) bovine in vitro-produced embryos were determined. Of the measured embryos, 64 were lysed for sex diagnosis by PCR. Average respiration rates of day 7 embryos (1.30 +/- 0.064 nl/h) were 3.4-fold higher than day 3 embryos (0.38 +/- 0.011 nl/h). On day 7, the average respiration rate of quality 1 blastocysts was significantly higher than the respiration rates of the lower qualities. For both day 3 and day 7 embryos, respiration rates were directly influenced by embryo diameter but did not differ between sexes. These results have demonstrated that the novel microsensor technology can be used to accurately and rapidly (8 min) measure the respiration rates of individual embryos at different developmental stages. Respiration rates were only in partial agreement with embryo morphology, suggesting a slight discrepancy between these two methods in assessing embryo quality. It is likely that a combined assessment of embryo respiration and morphology would improve embryo classification and subsequent selection.

Animals↗
PubMed1997

[Apical hypertrophic cardiomyopathy with right ventricular involvement].

We report right ventricular involvement in apical hypertrophic cardiomyopathy (HCMP) in two women and one man, aged from 19 to 44 years-old, who presented different signs from those with left ventricular disease (who have good clinical evolution), with signs and symptoms of severe diastolic restriction, showing great atrial enlargement and two with atrial fibrillation and death due to thromboembolism. The right ventricular involvement in apical HCMP leads to a worst prognosis than isolated left ventricular disease, does not have the typical electrocardiographic changes and presents with ventricular restriction and tricuspid regurgitation.

Adult↗
PubMed1997

[Is the apical hypertrophic cardiomyopathy seen in one population in Rio de Janeiro city similar to that found in the East?].

PURPOSE: To investigate the differences between clinical aspects and evolution of apical hypertrophic cardiomyopathy (AHCM) seen in Rio de Janeiro and the Oriental form, which was the first described. METHODS: In 156 patients with AHCM diagnosed in our institution, there were 13 (8.34%) with the apical form of the disease, whose clinical settings, diagnostic procedures and evolution were studied. RESULTS: There were 8 males and 5 females, between 19 and 75 years old, all white. Electrocardiogram (EKG) showed giant T waves in precordial leads in 10 (76.92%), echocardiogram (ECHO) demonstrated apical hypertrophy in all, 10 (76.92%) had only in the left ventricle, 2 in right ventricle and one involving both. Cineangiography corroborated ECHO findings. Follow-up ranged from 6 to 294 months (x = 95.4). Two deaths occurred in patients with RV involvement, due to large atria, atrial fibrillation, tricuspid or mitral insufficiency and thromboembolism. Among the survivors, the patient with RV disease has diastolic restriction and the ones with LV involvement, 9 are asymptomatic using either propranolol (8) or amiodarone (1), and one uses no medication. CONCLUSION: A HCM seen in Rio de Janeiro is similar to that found in the Orient (Japan) regarding presentation, diagnosis and evolution; but in 3 patients we have found RV disease, not described in Japan, characterizing a distinct group with a worse evolution.

Adolescent↗
PubMed1983

Isolated tricuspid stenosis: report of a case submitted to valvular commissurotomy.

In this report, a rare case of tricuspid stenosis uncomplicated by other valve lesions is presented, with clinical, hemodynamic, echocardiographic, and angiographic studies. The patient was markedly incapacitated, mostly as a result of a restricted cardiac output. Tricuspid commissurotomy was performed, with a stenotic deformity of a bicuspid atrioventricular valve, probably of congenital origin, found at surgery. Considerable improvement was observed, notwithstanding the persistence of some signs of residual tricuspid obstruction as a result of an incomplete commissurotomy, to avoid increasing the slight degree of preexistent valvular regurgitation.

Cardiac Catheterization↗