摘要:

Measurements have been made of the peripheral vascular factors influencing venous return, and hence cardiac output, in the fetus. These measurements show the fetus maintains a high venous return by means of a high mean systemic pressure, or driving pressure for venous return, and a low resistance to venous return. Increases in fetal blood volume cause increases in mean systemic pressure with no change in resistance to venous return and, as a result, venous return is increased. These studies show the possible importance of peripheral vascular factors in the control of cardiac output.

ISSN:0378-7346    

DOI:10.1159/000301088

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A retrospective study was designed to contrast the intrauterine pressure wave form characteristics of hypocontractile labor in patients with and without obstruction and before and after oxytocin therapy. No differences were observed between the patient groups (vaginal delivery vs. cesarean section), either before or after oxytocin. Problems in defining adequate contractility in patients with possible obstructed labors are discussed, and new parameters of potential value are identified.

ISSN:0378-7346    

DOI:10.1159/000301091

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Evidence obtained from laser light-scattering spectroscopy suggests that the molecular arrangement of cow estrous cervical mucus is an ensemble of entangled random-coiled macromolecules rather than a cross-linked macromolecular network, the model heretofore widely accepted. This new model can account for the following phenomena: The viscoelastic properties of the estrous mucus and human mid-cycle cervical mucus are the result of the way in which the glycoproteins are entangled. Variations of these properties during the reproductive cycle may simply be due to changes in the water content of the cervical mucus. Penetration of spermatozoa in mucus may be entirely mechanical without involving any kind of enzymatic lysis of cross-links (this is supported by changes in the pattern of spermatozoa flagellation during sperm penetration of cervical mucus as shown in motion picture films). The orientation of spermatozoa in the cervical mucus need not be due to the presence of ‘channels’ between micelles but simply to an artifact, the stretching or flow of the mucus, which orients the entangled macromolecules and thus facilitates the penetration of spermatozoa in an axis parallel to them.

ISSN:0378-7346    

DOI:10.1159/000301094

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The syncytial trophoblast has previously been shown to have minimal intrasyncytial galactosyltransferase activity at term. The biochemical and autoradiographic study reported here shows that the microvillous surface of term human placental syncytial trophoblast has a galactosyltransferase activity capable of transferring 3H-galactose from uridine diphosphate-D-galactose-l-3H to trichloroacetic-acid-precipitable, endogenous acceptors. This capability of resynthesizing cleaved galactose moieties in the glycocalyx, without dependence on cytoplasmically located galactosyltransferases, would allow for reinstatement of the original surface molecular configuration without requiring synthesis and insertion of a completely new membrane molecule. It is suggested that the surface galactosyltransferase might function to repair damage to syncytial trophoblast glycocalyx induced by enzymes in maternal blood.

ISSN:0378-7346    

DOI:10.1159/000301097

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The supine hypertensive or ‘roll-over’ test (ROT) was performed serially in 24 primigravid patients between 27 and 35 weeks of gestational age. Pregnancy-induced hypertension (PIH) developed in 3 women (12.5%). Test reproducibility one week to the next in the same patient was poor. A false-positive ROT was noted for 83% of our patients, a false-negative test for 12.5%. We conclude that serial testing reveals marked variations in response that reflect inherent biologic fluctuations that limit the predictive value of the ROT for screening outpatients.

ISSN:0378-7346    

DOI:10.1159/000301100

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The possibility that 24-hour rhythms exist in uterine blood flow (UtBF) and umbilical blood flow (UmBF) was investigated in 5 days postoperative chronically instrumented near-term pregnant sheep acclimated to a controlled environment. UtBF, UmBF and pressure measurements were made at 15-min intervals over 24 h beginning at 0800 h. Each data series was examined for the presence of significant rhythms of a 24-hour period using a method of Fourier analysis. UtBF 24-hour rhythms were found in all ewes; UmBF 24-hour rhythms were found in 4 of 5 lambs. A consistent reciprocal phase relationship between UtBF and UmBF was evident within animals. There were no associated rhythms in maternal arterial, fetal arterial, or amniotic fluid pressures. These results indicate that the presence of circadian rhythms must be considered as a possible variable when long-term uteroplacental hemodynamic studies are planned.

ISSN:0378-7346    

DOI:10.1159/000301103

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

10 fetal lambs prepared with sampling catheters in the common umbilical vein and distal aorta were studied at 2 h, 2 and 4 days postoperatively. Umbilical blood flow was measured by a diffusion equilibrium method. Oxygen, lactate, pyruvate, glucose and α-amino nitrogen concentrations were determined on umbilical arterial (UA) and umbilical vein (UV) blood. Fetal oxygen consumption averaged 10.4, 10.6 and 1.0 ml kg-1min-1 for the three study periods. Lactate/pyruvate ratios were higher in UV than in UA in 17 of 20 experiments. Significant reductions (p < 0.05) in (1) maternal mixed venous-UA glucose concentration difference, and (2) UA glucose concentrations occurred at 2 and 4 days compared to the 2-hour period. Fetal α-amino nitrogen balance was negative at the 2-hour period, but positive 2 days and 4 days postoperativel

ISSN:0378-7346    

DOI:10.1159/000301106

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The effects of estradiol, estrone and estriol on the tonus of the isolated vascular segments of human umbilical artery were studied by a perfusion technique. Estradiol (10 μg/ml), estrone (10 μg/ml) or estriol (2 and 10 μg/ml) produce relaxation of the vascular bed which was reflected in a significant reduction in basal pressure of segments perfused at constant rate. A dose-dependent relationship was demonstrated for estriol. The time dependence and extent of relaxation were similar for all three natural estrogens.

ISSN:0378-7346    

DOI:10.1159/000301109

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

An attempt of granulosa cell tumor (GCT) induction by prolonged administration of exogenous pregnant mare’s serum gonadotropin (PMSG) to young, mature, and middle-aged Balb-C mice resulted mainly in stromal luteal cell proliferation. 48.9% of young mice, 64.5% of mature mice and 65% of middle-aged mice developed luteal cell proliferation. This effect seemed to be dependent on duration of treatment, mainly in young mice. Young mice injected for less than 6 months developed significantly less luteal cell proliferation than those injected for more lhan 6 months. Only 1 GCT was found. This study seems to support the contention that besides gonadotropin stimulation, other factors may be involved in GCT development. A large number of PMSG-injected mice developed generalized lymphosarcoma, the mechanism of which remains unknown.

ISSN:0378-7346    

DOI:10.1159/000301112

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:0378-7346    

DOI:10.1159/000301115

出版商:S. Karger AG    

年代:1977

数据来源: Karger