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Biomedical subjects

S Britten

Publications and source records attributed to S Britten.

16 recordsLinked to original sources
PubMed1995

Comparison of pulsatility indices on the day of oocyte retrieval and embryo transfer.

Transvaginal ultrasonography with colour blood flow imaging and analysis of impedance to uterine arterial blood flow has been used to provide an index of uterine receptivity for implantation after IVF/embryo transfer. A mean uterine arterial pulsatility index (PI) > 3.0 at the time of embryo transfer predicted 35% of failures to become pregnant. Cryopreserving embryos in non-receptive cycles and transferring them in receptive cycles would be expected to improve pregnancy rates. Earlier decisions regarding embryo cryopreservation can be made if receptive cycles can be predicted at the time of oocyte retrieval rather than at embryo transfer. To assess differences in uterine artery impedance, PI were measured serially in 107 women on both the day of oocyte retrieval and the day of embryo transfer. Mean PI on the day of oocyte retrieval was 2.52 +/- 0.59, and on the day of embryo transfer was 2.78 +/- 0.45. No significant difference was observed when PI determined on the day of oocyte retrieval were compared with PI on the day of embryo transfer. These data suggest that the PI measurement done on the day of oocyte retrieval could substitute for the measurement done on the day of embryo transfer. This would allow prediction of non-receptive endometria earlier in the cycle. Further studies are needed to evaluate whether cryopreservation of embryos and transfer when the uterus is more receptive will increase the implantation rates.

Adult↗
PubMed1994

Ultrasonographic predictors of implantation after assisted reproduction.

OBJECTIVE: To assess the utility of endometrial thickness, echogenic endometrial pattern, and uterine artery impedance measured as pulsativity index in predicting implantation. DESIGN: Prospective case-controlled study of infertile patients undergoing assisted reproductive technologies (ARTs). PATIENTS: Four hundred five women undergoing ARTs were studied: 100 women after ET of thawed embryos in natural cycles (frozen ET), 107 women after standardized IVF-ET, 99 women receiving donor oocytes after controlled endometrial development with estrogen and P, and 99 women undergoing IUI with various ovarian stimulation regimens (none, 16; GnRH, 7; clomiphene citrate [CC], 29; hMG, 47). INTERVENTIONS: Transvaginal ultrasonographic examination performed on the day of hCG administration during stimulated cycles; on E2 day 15 during controlled endometrial cycles; and on the day of ovulation during natural, CC, and GnRH pump cycles. MAIN OUTCOME MEASURE: The endometrial thickness, echogenic pattern, and pulsativity index results in 170 conception cycles were compared with 235 nonconception cycles. RESULTS: When conception and nonconception cycles were compared, no difference in mean endometrial thickness and significant differences in the frequency of nonmultilayered pattern and pulsativity index > 3.3 were observed. Forty-seven percent of nonconception and 9% of conception cycles were associated with at least one of these factors. CONCLUSION: Ultrasonic measurements of pulsativity index, resistance index, and echogenic pattern are useful in predicting implantation after assisted reproduction.

Case-Control Studies↗
PubMed1994

Very early (24-56 days from last menstrual period) embryonic heart rate in normal pregnancies.

To determine embryonic heart rate in early gestations, 426 ultrasonographic examinations from 24 to 56 days from onset of last menstrual period (LMP) were studied. All pregnancies had a subsequent successful outcome. Transvaginal ultrasonography was performed using an Acuson 128 10XP with a 5 MHz probe. Embryonic heart rate was determined by M-mode. No embryonic heart rate was observed prior to 34 days of gestation from onset of LMP (n = 65). At 35 days, two of 13 (15%) pregnancies had cardiac activity, and by 36 days 16 of 19 (82%) pregnancies had cardiac activity. By day 37 from onset of LMP all pregnancies demonstrated embryonic cardiac activity. From days 34 to 56, mean embryonic heart rate rose from 94 to 166 beats/min. We conclude that embryonic cardiac activity is first apparent at day 34 and should be visible by day 37 in normal pregnancies.

Female↗
PubMed1994

Effect of inhaled bradykinin on indices of airway responsiveness in asthmatic subjects.

Asthma is characterized by airway hyperresponsiveness, a physiopathological abnormality which may result from the complex interplay between inflammatory cells and proinflammatory mediators. Although kinins are thought to play a role in the pathogenesis of bronchial asthma, it is not known whether bradykinin is able to induce airway hyperresponsiveness. We have, therefore, investigated the effect of inhaled bradykinin on the changes in airway calibre and in airway hyperresponsiveness to histamine, in a double-blind, randomized study of nine asthmatic subjects. Subjects were studied on two study periods, separated by at least 15 days. On the first day of each study period, subjects inhaled either a single dose of bradykinin or methacholine (placebo) with changes in airway calibre being followed as forced expiratory volume in one second (FEV1) and as the maximum expiratory flow rate measured at 70% of the vital capacity below total lung capacity (TLC) from a partial forced expiratory manoeuvre (Vp30) at 3, 5, 10, 15, 30, 45 and 60 min, and then every hour for 7 h. Airway responsiveness to histamine, expressed as the provocative concentrations producing a 20% fall in FEV1 and 40% fall in Vp30 (PC20FEV1 and PC40Vp30), was measured at 3 and 7 h after inhaling the agonists, then on days 1, 3, 7 and 14. Inhalation of bradykinin caused rapid bronchoconstriction that peaked at 3-5 min. When compared to placebo, no significant difference in histamine responsiveness was seen after bradykinin in terms of changes in PC20FEV1 values.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1985

Chemical weapons.

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Chemical Warfare↗
PubMed1979

A study of stump growth in children with below-knee amputations.

The growth of the stump has been studied in eighteen children with below-knee amputations. Measurements were available shortly after operation and later at skeletal maturity. It was found that all patients achieved less than expected growth and that the reduction was greater in those patients who had had amputation for congenital deformity.

Adolescent↗
PubMedDate not supplied

Soviet AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Health care in Nicaragua.

A two-week health study tour in Nicaragua in 1987 organized by the Health Network of the (British) Nicaragua Solidarity Campaign afforded the author of this report access to health service planning, first-hand observation of the immunization programme, and visits to centres for rehabilitation of the disabled, both from the war and civil causes. The efficacy of the low technology immunization and oral rehydration programmes is contrasted with the struggle to rehabilitate the war disabled with grossly inadequate resources.

Child↗