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Biomedical subjects

C B Martin

Publications and source records attributed to C B Martin.

At least 55 records · Page 3Linked to original sources
PubMed1985

Behavioural states in growth-retarded human fetuses.

Behavioural state observations were carried out on 12 fetuses which subsequently had birthweights below the 10th percentile. Their gestational ages at the time of study ranged from 32 to 40 weeks. Real-time ultrasound scanning was used to detect fetal body and eye movements, and the fetal heart rate was continuously recorded using a clinical fetal monitor. None of these fetuses was severely acidemic or depressed at birth. Findings in the growth-retarded fetuses were compared with those obtained in the fetuses of 14 low risk nulliparae and 14 low risk multiparae by means of the same techniques (van Vliet et al. (1985) Early Hum. Dev., 12, 121-135.; Nijhuis et al. (1982) Early Hum. Dev., 6, 177-195). The appearance of states seemed to be delayed in the growth-retarded fetuses. States were present in only three of eight growth-retarded fetuses studied at 40 weeks, whereas only one of 16 low risk fetuses did not show states at this age. Also at 40 weeks, the proportion of discordant association of the state variables was increased in the growth-retarded fetuses in comparison to the low risk group. There were no consistent differences between the two groups in the occurrence of defined combinations of parameters of the state variables at earlier ages. The growth-retarded fetuses showed differences in the quality and quantity of somatic motility in comparison to low risk fetuses of equivalent gestational age. These observations suggest that some aspects of central nervous system function are disturbed in growth-retarded fetuses, even in the absence of fetal distress.

Birth Weight↗
PubMed1984

Intrauterine growth of chronically instrumented rhesus monkey fetuses.

The effect of surgical and experimental manipulations on intrauterine growth of the fetus was investigated in 61 rhesus monkey fetuses in which chronic preparations were attempted. The surgical procedure consisted of hysterotomy and insertion of vascular catheters and included unilateral ligation of the fetal carotid artery. The mother was kept in a restraining chair after the operation for the duration of the preparation (0 to 39 days). Thirty-four fetuses who died within 48 hours after operation served as the control group for the growth parameters. The remaining fetuses that survived 7 days or more after the operation were included in the experimental group. Body weight, crown-rump length, crown-heel length, and foot length of the fetus and placental weight were measured at the termination of the preparation. There were significant linear correlations between all parameters and gestational age. Comparison between the control and experimental groups revealed that none of the parameters from the experimental group differed significantly from those of the control group. No relationships were found between the duration of the preparation and any of the parameters. Total brain weights from 19 fetuses exhibited a significant increase with gestational age and these values were within the normal range reported previously. There were no significant differences in weight between right and left cerebral hemispheres. No evidence of unequal blood flow to the cerebral hemispheres was found with the radioactive microsphere technique. The data suggest that the surgery performed on both the mother and the fetus and prolonged maternal restraint did not alter intrauterine fetal development.

Animals↗
PubMed1984

The L/S ratio in vaginally collected amniotic fluid: a misleading result in a breech presentation.

A case is reported in which serial L/S ratios, determined from fluid samples collected vaginally after premature rupture of the membranes, led to a grossly erroneous conclusion of fetal pulmonary immaturity. The fetus was in breech presentation, and in retrospect several 'amniotic fluid' samples consisted largely of fetal urine. Determination of the creatinine concentration of suspect samples should permit distinction to be made between mixed amniotic fluid and fluid containing a disproportionately large amount of fetal urine when the possibility of this error exists.

Adult↗
PubMed1984

Female urethral pressure profile; reproducibility, axial variation and effects of low dose oral contraceptives.

The variability of the female urethral pressure profile as determined with the microtransducer technique was studied in a group of healthy nulliparous women according to a standardized methodology. Estimation of the short term reproducibility, as well as investigation of which of several serially recorded urethral pressure profiles can be considered as most representative of the basal condition, was carried out by performing serial urethral pressure profile recordings within the same study session in 12 women. Estimation of the long term reproducibility and investigation of the influence of axial rotation of the transducer membrane on the measurements were carried out in 20 women who were on low dose oral contraceptives. No influence of low dose oral contraceptives on the urethral pressure profile measurements could be detected. When serial recordings were made within the same study session, the lowest values for the urethral closure pressure were generally observed in the 3rd and 4th recordings. The short term and long term reproducibility of urethral pressure profile measurements were generally the same for the measurements in both the supine and the sitting positions. Rotation of the transducer membrane as well as positional changes significantly influenced the urethral pressure profile recordings. The recordings in which the transducer was oriented ventrally generally showed a shorter urethral length and a higher closure pressure than those in which the pressure transducer was oriented laterally or dorsally. These observations as well as the observations made during dynamic testing indicate an asymmetrical distribution of urethral closure forces in healthy nulliparous women.

Adult↗
PubMed1983

The rhythmicity of fetal breathing varies with behavioural state in the human fetus.

The rhythmicity of human fetal breathing movements was studied during two different behavioural states (1F and 2F, respectively), using real-time B-scan-directed M-mode ultrasound recordings. The mean breath-to-breath interval durations and the standard deviations (SD), and the standard deviations of the interval differences (SDDSI) were calculated. The mean breath-to-breath interval duration was not significantly shorter during 1F than during 2F. SD and SDDSI, however, showed significantly lower values during 1F, demonstrating that the fetal breathing rhythm is more regular during state 1F than during state 2F epochs. Regular fetal breathing is thus a concomitant of state 1F.

Female↗
PubMed1982

The urethral pressure profile in pregnancy and after delivery in healthy nulliparous women.

Simultaneous urethrocystometry by means of a dual microtransducer catheter was performed according to a precise, standardized technique serially at 8, 16, 28, and 36 weeks of pregnancy and at 8 weeks post partum in 43 healthy nulliparous women. The urethral pressure profile at rest and the effect of stress (cough) on the urethral pressure profile during pregnancy and after delivery were measured. At each recording session, blood was obtained for determination of 17 beta-estradiol (E2), progesterone (P), and 17-alpha-hydroxyprogesterone (17-OH-PO). The continence parameters functional urethral length and urethral closure pressure, as well as the urethral closure pressure response to stress, did not change systematically during the course of pregnancy. Engagement of the presenting part at 36 weeks did not influence the urethral pressure profile measurements. Alterations in hormone levels during pregnancy were not correlated with the changes in urethral pressure profile measurements. Both urethral pressure and length parameters in all women who underwent vaginal delivery were notably decreased 8 weeks post partum when compared with early pregnancy values and with values obtained in a group of healthy nulliparous women in the follicular phase of the cycle. The decrease in length parameters was not observed in the six women in whom delivery was by cesarean section. The postpartum changes were not significantly correlated with the duration of the second stage of labor or with the presence or absence of an episiotomy. Also, no relationship with infant birth weight was found. Values of the urethral pressure profile parameters below the median value and defective transmission of pressure over the urethra were observed in almost all women who experienced stress incontinence during pregnancy and/or after delivery. These observations suggest that an inherent weakness of the urethral sphincter mechanism plays a key role in the pathogenesis of stress incontinence.

Adult↗
PubMed1982

Fetal heart rate accelerations and late decelerations during the course of intrauterine death in chronically catheterized rhesus monkeys.

The appearance of late decelerations and the disappearance of accelerations in the fetal heart rate were observed during the days that preceded intrauterine fetal death in nine chronically instrumented rhesus monkeys. All nine animals had recovered satisfactorily from the initial surgical procedure, as evidenced by normal biophysical and biochemical parameters. After recovery, all the fetuses had shown accelerations and no late decelerations with spontaneous uterine contractions. The mean duration of the preparations was 16.1 days. The duration of the preterminal observation period varied from 3 to 13 days, during which time no experiments were performed. The fetuses died during labor at a mean gestational age of 143 days. Late decelerations were the first sign of fetal deterioration and occurred with a slight but significant decrease in fetal PaO2 without changes in pH, whereas accelerations in fetal heart rate were still present. The loss of accelerations in fetal heart rate was a later phenomenon and was associated with significant reductions in fetal pH and PaO2.

Animals↗
PubMed1982

The influence of long term beta-mimetic drug administration during pregnancy on blood loss postpartum.

Early blood loss after-delivery was measured in all prematurely ending singleton pregnancies (amenorrhea 29-38 wk) during which the patients had been treated with beta-mimetics (ritodrine or fenoterol) for the prevention of premature labor, during a 4 yr study period (1975--1978) (n = 129). For comparison, postpartum blood loss was measured in the same way in all other (not treated) patients who delivered with the same gestational ages during the first 2 yr of the investigation (n = 176). Only vaginal deliveries were included and some patient categories were excluded. Placental weight and episiotomy status were found to effect the amount of early postpartum blood loss at a significant level. Blood loss after delivery was found not to be increased by chronic beta-mimetic treatment, even when this treatment ended less than 24 h before delivery. Moreover, when the treatment--delivery interval exceeded 24 h, the average amount of blood loss by treated patients was less than that of the untreated patients in some comparison categories. No difference in the amount of blood loss was found according to the specific drug that had been used.

Birth Weight↗
PubMed1982

Are there behavioural states in the human fetus?

The aim of this study was to search for the existence of behavioural states in the human fetus and to describe their developmental course. In a longitudinal study, 14 low-risk fetuses were studied at 2-week intervals from 32 weeks of gestation onward. Fetal body movements as well as fetal eye movements, visualized by means of real-time ultrasonic imaging, and fetal heart rate patterns, recorded by means of a cardiotocograph, were used as state variables. At 38 and 40 weeks, four distinct behavioural states, named states 1F through 4F and corresponding respectively to states 1 through 4 of the neonate, could be identified. That these constellations of parameters represented true behavioural states was demonstrated by the stability of association of parameters for prolonged periods and by the simultaneity of change of parameters at state transitions. There is evidence for episodes of wakefulness in the fetus. Before 36 weeks, cycles were present in each of the state variables and combinations of parameters typical of particular states were observed. However, the relatively short durations of these combinations and the lack of simultaneity of change in the three state variables support the conclusion that these periods of coincidence occurred by chance and did not represent organized behavioural states.

Activity Cycles↗
PubMed1981

Effect of acute hypoxemia and respiratory acidosis on the fetal heart rate in monkeys.

The fetal heart rate (FHR) response to acute nonacidemic hypoxemia and to acute respiratory acidosis was studied in unanesthetized pregnant monkeys by means of chronically implanted catheters and electrodes. Average FHR and short- and long-term FHR variability were analyzed separately. The FHR response to either hypoxemia or hypercapnia consisted of slowing and increased variability. The slowing was more consistent with hypercapnia than with hypoxemia. Long-term FHR variability increased with both test stresses. The increase in short-term FHR variability was much greater in response to hypoxemia than to hypercapnia. Both the FHR slowing and the increases in variability in response to the test stresses were reduced by prior administration of atropine to the fetus.

Acidosis, Respiratory↗
PubMed1981

Urodynamic studies in the normal menstrual cycle: the relationship between hormonal changes during the menstrual cycle and the urethral pressure profile.

The influence of endogenous gonadal steroids on the urethral pressure profile (UPP) was studied in 27 healthy nulliparous women with the normal ovulatory cycles. The UPP and hormonal values were recorded in the follicular phase, at midcycle, and early and late in the luteal phase. Simultaneous urethrocystometry was performed by means of the microtransducer technique, according to a precise standardized methodology. The parameters of the UPP, as defined by the Standardization Committee of the International Continence Society, and the area under the urethral closure pressure curve (integrated pressure) were calculated. Reproducibility of the UPP measurements was evaluated. In addition to a basal body temperature (BBT) chart, serum levels of 17 beta-estradiol (E2), progesterone (P), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin were measured at each study session in order to confirm a normal ovulatory pattern for that cycle and for comparison with the urodynamic parameters. The mean values and standard deviation of the UPP parameters in healthy nulliparous women in the supine and sitting positions are presented. Values of the pressure measurements obtained during one menstrual cycle did not change systemically with the hormonal alterations. At midcycle and early in the luteal phase, however, and anatomic and functional lengths of the urethra were consistently increased over those found in the early follicular and late luteal phases. The data suggest a causal relationship between the changes in serum E2 concentrations and the changes in urethral length.

Adult↗
PubMed1981

Effect of catecholamine on fetal breathing activity in rhesus monkeys.

The effect of various catecholamines on fetal breathing movements (FMB) was studied in 10 established chronic fetal rhesus monkey preparations. Norepinephrine, epinephrine, isoproterenol (all 1:10(5) [w/v] in concentration), or saline was infused intravenously to the fetus, each on five separate occasions. The infusion of the catecholamines was started at 0.02 ml/min and increased in a stepwise fashion until the fetus exhibited cardiovascular responses. The infusion rate was then maintained for 30 minutes to observe FBM. The incidence of FBM was determined for each 5-minute period and also expressed as a percentage of preinfusion values. Statistical analysis revealed that the incidence of FBM was significantly increased by isoproterenol and decreased by norepinephrine. Epinephrine did not consistently alter the incidence of the FBM.

Animals↗