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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 220 simultaneous pairs of measurements of cardiac stroke volume were made in twelve women before and during Caesarean section in order to compare impedance cardiography with the thermodilution method. A significantly higher coefficient of correlation was found before (r = 0.77) than during anaesthesia (r = 0.55). Further, there was a significant difference in the slope of the regression lines: before anaesthesia the slope was 1.07 and during anaesthesia with thiopentone, nitrous oxide, oxygen and suxamethonium it was 0.45. Significant changes in the intercept on the Y-axis were found before (-13.9 ml) and during anaesthesia (33.4 ml). When the uterus was displaced upwards and to the left from the 15 degrees tilt position the stroke volume and the cardiac output were increased when measured by both methods to nearly the same values as in the left lateral position. It is concluded that the impedance method is reliable for measuring cardiac stroke volume in late pregnancy under physiological conditions in the conscious patient, but that it cannot replace the thermodilution method in pharmacological studies.
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PMID:Measurements of cardiac stroke volume in various body positions in pregnancy and during Caesarean section: a comparison between thermodilution and impedance cardiography. 53 85

Ketamine, currently being evaluated as an obstetric anaesthetic agent, is said to provide analgesia without depression of the protective airway reflexes or depression of the respiratory or cardiovascular systems. We have studied the effects of ketamine on the uterine blood flow, the foetus and the newborn in five monkeys (Macaca nemistrina). Uterine blood flow, (UBF) was measured by the steady-state infusion technique using tritiated water as the indicator. All of the variables were measured during a control period and again at 10 and 90 min after the administration of ketamine in doses of 2 mg/kg in three monkeys or 1 mg/kg in two. Maternal respiration was maintained at normal physiological levels without significant variation. The maternal mean arterial pressure (MAP), cardiac output (CO), and stroke volume (SV) did not change significantly, but heart rate (HR) did increase significantly following the injection of ketamine and remained increased for the duration of the study. UBF, a-v oxygen difference, and the oxygen consumption of the uterus and its contents remained stable throughout. During the intrauterine period the foetus did not seem to be affected by the two doses of ketamine. However, the three newborn monkeys delivered of the mothers who had reveived ketamine 2 mg/kg had profound respiratory depression. This was not seen in the two infants delivered from mothers receiving 1 mg/kg. Others have shown that neonatal depression is dose- and time-related. We conclude that ketamine should be administered to obstetric patients in small single doses or by continuous infusion in very low concentrations.
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PMID:Respiratory depression in newborn monkeys at Caesarean section following ketamine administration. 81 Dec 35

Action taken by the Food and Drug Administration (FDA) toward the th erapeutic use of estrogens is reported. The FDA has 1st ordered revision of physician-labeling for estrogens, and 2nd has prepared a brochure explaining the advantages and disadvantages of estrogen therapy to patients. Some of the points made in the new labeling and brochure are: 1) the risk of cancer of the uterus increases with duration of use and dosage; 2) users of estrogens should be examined by their physicians at least every 6 months; 3) estrogens should never be given to pregnant women; 4) estrogens should not be given in cases of breast or uterine cancer, undiagnosed abnormal vaginal bleeding, clotting in the legs and lungs, or previous heart disease, angina, or stroke; and 5) estrogens should not be used to treat menopausal nervousness, as they have proved ineffective, or for improving the complexion. There is also no evidence that estrogens are effective in preventing threatened or habitual abortion. It is recommended that estrogens be administered cyclically (3 of 4 weeks), and that the dosage be reduced or discontinued every 3-6 months to assess the need for their continued use.
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PMID:Informing patients about estrogens. 82 30

Although chorion carcinoma of the uterus is the seventh commonest in the comparative frequency of malignant tumours seen at the Cancer Registry of the University College Hospital, Ibadan, Nigeria (being exceeded in order of commoness by the reticuloendothelial tumours, carcinoma of the cervix, liver, breast, stomach and ovary), it is the most frequent source of tumour deposit of the brain in this hospital. Between 1960 and 1969, 197 Nigerians with chorion cancer of the uterus were admitted to UCH; in twenty-five of them the nervous system was involved during the course of their disease. The neurological involvement presented as acute cerebrovascular accident in fourteen, encephalitis in five; as primary intracranial space-occupying lesion in three cases and in one patient, as cord compression. There were no obvious neurological features in two cases in which necropsy revealed brain metastases. Involvement of the nervous system carries a poor prognosis in chorion cancer of the uterus.
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PMID:The neurology of metastatic chorion carcinoma. 82 2

In quail oviduct epithelium, as in all metazoan and protozoan ciliated cells, cilia beat in a coordinated cycle. They are arranged in a polarized pattern oriented according to the anteroposterior axis of the oviduct and are most likely responsible for transport of the ovum and egg white proteins from the infundibulum toward the uterus. Orientation of ciliary beating is related to that of the basal bodies, indicated by the location of the lateral basal foot, which points in the direction of the active stroke of ciliary beating. This arrangement of the ciliary cortex occurs as the ultimate step in ciliogenesis and following the oviduct development. Cilia first develop in a random orientation and reorient later, simultaneously with the development of the cortical cytoskeleton. In order to know when the final orientation of basal bodies and cilia is determined in the course of oviduct development, microsurgical reversal of a segment of the immature oviduct was performed. Then, after hormone-induced development and ciliogenesis, ciliary orientation was examined in the inverted segment and in normal parts of the ciliated epithelium. In the inverted segment, orientation was reversed, as shown by a video recording of the direction of effective flow produced by beating cilia, by the three-dimensional bending forms of cilia immobilized during the beating cycle and screened by scanning electron microscopy, and by the position of basal body appendages as seen in thin sections by transmission electron microscopy. These results demonstrate that basal body and ciliary orientation are irreversibly determined prior to development by an endogenous signal present early in the cells of the immature oviduct, transmitted to daughter cells during the proliferative phase and expressed at the end of ciliogenesis.
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PMID:Determination of ciliary polarity precedes differentiation in the epithelial cells of quail oviduct. 175 9

Cold exposure (6 weeks at 4 degrees C) of normotensive (Wistar-Kyoto) and stroke-prone spontaneously hypertensive female rats led to cardiac hypertrophy (in stroke-prone spontaneously hypertensive rats), increased the level of plasma thyroxine, and increased the alpha-myosin heavy chain expression in the left ventricle. In contrast, myosin heavy chain expression of both main mesenteric artery and uterus was not affected by cold stress and chronic hypertension, suggesting different regulation of myosin heavy chain expression in smooth and cardiac muscle in vivo.
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PMID:The influence of cold stress on the myosin heavy chain expression of cardiac and smooth muscle in normotensive and spontaneously hypertensive female rats. 183 32

To assess the effects of the presence of the uteroplacental circulation on the systemic arterial pressure, blood volume, and cardiac output during pregnancy, we measured those variables and plasma renin activity (PRA) during a 30-min period before and after occlusion of the uterine circulation. After uterine vascular occlusion, pregnant rabbits (n = 7) experienced a drop in mean arterial pressure of 8.7%, heart rate of 9.5%, cardiac output of 30.2%, and hematocrit of 18.2% (each with P less than 0.05). Stroke volume decreased an average of 29.7%; however, it did not reach significance. PRA and venous pressure did not change significantly from the control period (P greater than 0.1). Nonpregnant rabbits did not experience changes in arterial or venous pressures, hematocrit, heart rate, cardiac output, or PRA after closure of the uterine circulation. To exclude the possibility that the findings were secondary to the release of toxic products to the peritoneal cavity by the ischemic pregnant uterus, we also studied the effect of closure of the uterine circulation in five anesthetized pregnant guinea pigs. These animals' uteri were exteriorized and maintained in a sealed plastic container during the experiment. In these animals, arterial pressure decreased 15.6% by 10 min (P less than 0.05). The finding of a significant decrease in arterial pressure and heart rate is compatible with the idea that the uterine circulation produces a substance with a short half-life that has a significant direct effect on the heart and/or systemic vascular tone.
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PMID:Cardiovascular changes after closure of uterine circulation during pregnancy. 236 Jun 92

Alterations in maternal physiology during pregnancy affect the physiological respect to aerobic exercise. Maternal resting oxygen consumption (VO2) and cardiac output increase during pregnancy. Heart rate (HR) becomes progressively elevated through gestation, whereas stroke volume (SV) increases until the third trimester and then declines until term, probably because of diminished venous return. Plasma volume increases earlier and to a greater magnitude than red cell volume, resulting in the 'haemodilutional anaemia' of pregnancy and a decline in the oxygen-carrying capacity. Ventilation is greater during pregnancy because of elevated tidal volume and unchanged rate of breathing. The acute and chronic (training) responses to aerobic exercise during pregnancy have not been thoroughly investigated. Specifically, the effect of gestational age, maternal activity status, and type, duration and intensity of exercise on maternal cardiovascular response have only recently begun to be explored. During pregnancy cardiac output during submaximal exertion increases above values in non-pregnant women, except perhaps late in gestation. Both heart rate and stroke volume contribute to the elevated cardiac output. Changes in submaximal exercise VO2 during pregnancy are dependent on the mode of exercise. At the same workload, VO2 increases during weight-bearing exercise, but usually does not differ from postpartum values during weight-supported exercise. One study found no change in VO2max during pregnancy compared to postpartum values. Some recent evidence indicates that the cardiac output vs VO2 relationship for pregnant women is within the range of average values reported for non-pregnant individuals. Exercise arterial-venous oxygen difference is lower during pregnancy, suggesting that the higher cardiac output is distributed to non-exercising vascular beds. The data are limited but suggest that the perfusion of exercising muscle is unchanged during pregnancy and that the major haemodynamic change is an augmented cardiac output so that blood flow to the uterus and fetus is not compromised. Only one study has measured blood flow during exercise in pregnant women. The reported 25% decrease in uterine blood flow during supine cycle exercise in women late in gestation must be interpreted cautiously because the uterus may obstruct the vena cava in the supine position. Studies of exercising pregnant animals usually indicate a decreased uterine blood flow but an enhanced oxygen extraction; the lower blood flow may be limited to non-placental areas. The applicability of these results to humans is unknown.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Aerobic exercise during pregnancy. Special considerations. 266 23

There are 2 striking differences in the practice of medicine in the US and in the UK: 1) in the former, there is a great emphasis on private medicine, and 2) in the US there is a much higher incidence of litigation, whereas in the UK, family planning services are free, and litigation in this area is almost unknown. British medical opinion agrees with the US on the following oral contraceptive contraindications: 1) cancer of the breast, ovary, uterus, vagina, or cervix; 2) coronary thrombosis, pulmonary embolism, deep vein thrombosis, angina pectoris, or stroke; and 3) unusual or unexplained vaginal bleeding. Both countries agree that it is inadvisable to give the combined pill over the age of 45, and over the age of 35 in smokers. The UK agrees with 75% of the routines adopted by US doctors on a patient's 1st visit for oral contraceptives. However, a patient who becomes amenorrheic while taking the pill is not regarded as lightly in the UK as she would be in the US; she is closely monitored. If 1 of 4 risk factors (age 35 or over, hypertension, obesity, or smoking) is evident, a patient in the UK is closely supervised while taking the pill. If more than 2 risk factors are present, a UK doctor may advise against the pill. Since the 1960s the media have both praisd and condemned the pill. There is no doubt that, in the field of contraceptive advice, the US and the UK lead the way, and a closer liaison between the 2 medical professions is essential to reassure patients.
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PMID:Contraceptive advice: how the English differ from the Americans. 309 Feb 54

In 33 out of 51 women studied in late gestation, the uterus was found to phasically compress the pelvic vessels and impede the venous blood flow during quiet standing. This caused a reduction of the cardiac stroke volume with resultant reduction of systemic blood pressure and a compensatory increased heart rate (range of increases 9-51 beats/min). In all cases uterine contractions (mostly subclinical) coincided with the phase of circulatory readjustment. Apparently, the contracting uterus, by changing its position and/or shape, relieves the venous obstruction and prevents decompensation. In the women displaying the uterine compression syndrome (UCS), uterine activity was markedly increased in standing compared to the left recumbent position. It was also investigated whether the UCS appeared more often and earlier in gestation in women with twins. In all 9 women with twin pregnancies (mean gestational age 28 5/7 weeks) the UCS associated with uterine contractions was apparent in the standing posture. Although at present no definite conclusions can be reached on the effect on the cervix of these contractions, quiet standing especially in twin pregnancies seems to provoke an increased uterine activity and should therefore be avoided.
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PMID:Premature contractions: are they caused by maternal standing? 383 29


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