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Biomedical subjects

H Nisell

Publications and source records attributed to H Nisell.

72 records · Page 4Linked to original sources
PubMed1989

The relation between life stress and hypertensive complications during pregnancy.

The relationship between life stress and hypertensive complications during pregnancy was studied in 345 women. A questionnaire was answered in the first trimester. The questions concerned education, employment, social network, traumatic experiences, housing conditions and stress of work. In this way a total life stress score for each woman was obtained. Hypertensive disorders, including chronic hypertension, were found in 63 women (18.3%). No significant difference was evident between women with low and high life stress scores with regard to hypertensive disorders during pregnancy. Nor did pressure changes during pregnancy differ between these groups.

Blood Pressure↗
PubMed1988

Reduced beta 2-adrenoceptor sensitivity in normal pregnancy but not in pregnancy-induced hypertension.

beta 2-Adrenoceptors on lymphocytes from healthy nonpregnant and pregnant women and patients with pregnancy-induced hypertension (PIH) were studied in vitro by a radioligand binding technique (125I-hydroxybenzylpindolol) and related to in vivo responses to infused adrenaline. Healthy pregnant women had significantly fewer beta 2-adrenoceptor binding sites than nonpregnant controls (47.1 +/- 5.6 vs. 73.6 +/- 10.5 fmol X mg-1 protein), PIH patients displaying intermediate values. Adrenaline-induced increases in plasma cyclic AMP (a beta 2-mediated in vivo response) also tended to be reduced during normal pregnancy. The systemic vasodilatation evoked by intravenously infused adrenaline and the density of lymphocyte beta 2-adrenoceptor binding sites were positively related in the nonpregnant controls (r = 0.50), but inversely related in both the pregnant controls (r = -0.40) and the PIH patients (r = -0.70). These regression lines differed significantly. The present results indicate a reduction of beta 2-adrenoceptor function during normal pregnancy, which is less pronounced in PIH, as well as an altered relationship between beta 2-mediated vasodilator responses and densities of beta 2-adrenoceptors on lymphocytes during pregnancy.

Centrifugation, Density Gradient↗
PubMed1988

Maternal hemodynamics and impaired fetal growth in pregnancy-induced hypertension.

Twenty-one subjects with pregnancy-induced hypertension were investigated with regard to the relationship between maternal hemodynamics and fetal growth. Five of the infants were small for gestational age (SGA) (less than tenth percentile) and 16 were appropriate for gestational age (AGA) (greater than tenth percentile). Mean arterial blood pressure, cardiac output, and stroke volume were significantly lower in the group of mothers with SGA infants than in the group with AGA infants (102 +/- 3 versus 115 +/- 3 mmHg, 5.8 +/- 0.2 versus 8.2 +/- 0.3 L/minute, and 76 +/- 7 versus 100 +/- 5 mL, respectively). The results of this investigation suggest that the hemodynamic background to the blood pressure increase in pregnancy-induced hypertension ranges from a low cardiac output, high vascular resistance condition to a high-output, low-normal resistance variant. The former subtype is often associated with the birth of an SGA infant.

Birth Weight↗
PubMed1987

Cardiovascular responses to isometric handgrip exercise: an invasive study in pregnancy-induced hypertension.

Nine patients with pregnancy-induced hypertension and nine healthy pregnant controls were compared in the last trimester with regard to cardiovascular and sympathoadrenal reactivity during a standardized isometric handgrip exercise test. At rest, the blood pressure elevation with pregnancy-induced hypertension resulted from increased systemic vascular resistance. The test increased the blood pressure, heart rate, cardiac output, stroke volume, and epinephrine and norepinephrine concentrations in arterial plasma, but did not change the calf or systemic vascular resistance. The responses of the two groups did not differ significantly with regard to any of the above variables. Thus, pregnancy-induced hypertension does not seem to be associated with exaggerated cardiovascular or sympathoadrenal reactivity to isometric exercise when compared with normal pregnancy. The mechanism underlying the blood pressure response appears to be similar in the two groups, ie, an increase in cardiac output.

Adult↗
PubMed1986

Sympathoadrenal and cardiovascular responses to mental stress in pregnancy-induced hypertension.

Nine patients with pregnancy-induced hypertension and nine healthy pregnant controls with similar gestational lengths were compared with regard to cardiovascular and sympathoadrenal reactivity during a standardized mental stress procedure (Stroop color word conflict test). The test induced increases in blood pressure, heart rate, cardiac output, arterial plasma epinephrine and norepinephrine concentrations, and a decrease in calf vascular resistance, but no changes in stroke volume or systemic vascular resistance. The responses of the two groups did not differ significantly with regard to any of the mentioned variables. Pregnancy-induced hypertension does not seem to be associated with an exaggerated cardiovascular or sympathoadrenal reactivity to mental stress when compared to normal pregnancy.

Adrenal Glands↗
PubMed1985

Sympathoadrenal and cardiovascular reactivity in pregnancy-induced hypertension. II. Responses to tilting.

Sympathoadrenal and cardiovascular responses to tilting were studied in patients with pregnancy-induced hypertension and healthy control subjects during the last trimester of pregnancy and 8 to 12 weeks post partum. Blood volumes were lower in the patients with pregnancy-induced hypertension during pregnancy (0.065 versus 0.081 L/kg, p less than 0.01) but not post partum. Tilting induced significantly smaller increases in heart rate and arterial plasma norepinephrine concentrations and smaller changes in blood pressure during pregnancy as compared to after pregnancy in both groups. Forearm vascular resistance increased significantly in both groups after pregnancy but only in the patients with pregnancy-induced hypertension during pregnancy. The forearm vasoconstrictor response to tilting was, in fact, totally abolished in the third trimester of normal pregnancy. The hypertensive patients had higher arterial plasma epinephrine levels at rest and greater epinephrine and norepinephrine responses to tilting than the control subjects during pregnancy. Normal pregnancy appears to reduce the circulatory and sympathoadrenal responses to orthostatic stress, presumably because of volume expansion that allows venous return to be better maintained in the upright position. The less pronounced pregnancy-induced increase in blood volume in patients with pregnancy-induced hypertension appears to explain the increased sympathoadrenal and forearm vascular reactivity in this group during pregnancy.

Adrenal Cortex↗
PubMed1985

Sympatho-adrenal and cardiovascular reactivity in pregnancy-induced hypertension. I. Responses to isometric exercise and a cold pressor test.

Sympatho-adrenal and cardiovascular reactivity was studied in patients with pregnancy-induced hypertension (PIH) and healthy pregnant controls subjected to an isometric handgrip test and a cold pressor test both during and after the pregnancy. At rest, heart rate was higher in the PIH group than in the control group both during and after pregnancy. Forearm vascular resistance was not affected by PIH or by pregnancy per se. During pregnancy arterial plasma adrenaline levels were suppressed in the control group both when compared with the PIH group and postpartum values. Arterial noradrenaline levels were similar and normal in the two groups at both examinations. The isometric exercise increased systolic and diastolic blood pressures, heart rate and noradrenaline and reduced vascular resistance similarly in the PIH and control groups on both occasions. Vasoconstrictor responses to the cold pressor test were reduced during pregnancy but there were no differences between the groups on either occasion. Noradrenaline responses to the cold pressor test were not influenced by PIH or by pregnancy per se. During pregnancy adrenaline responses to the two tests tended to be reduced in the controls but not in PIH. Our results indicate enhanced adrenomedullary activity in PIH when compared with the suppressed activity in normal pregnancy. Cardiovascular reactivity to the tests was similar in the PIH and control groups. The normal arterial noradrenaline levels at rest and during provocation do not support the contention of a generalized increase in sympathetic nerve activity in PIH.

Adult↗
PubMed1985

Cardiovascular responses to circulating catecholamines in normal pregnancy and in pregnancy-induced hypertension.

Patients with pregnancy-induced hypertension (PIH) and healthy pregnant and non-pregnant women were compared with regard to cardiovascular responses to i.v. infusions of noradrenaline (NA) and adrenaline (ADR). This resulted in physiologically relevant concentrations in arterial plasma (maximally 10 nmol/litre for NA and 6 nmol/litre for ADR). Non-pregnant women responded to NA with concentration-dependent increases in blood-pressure, which were caused by peripheral vasoconstriction, as systemic vascular resistance (SVR) was increased by 21%. Cardiac output was reduced by 6%. ADR caused concentration-dependent decreases in SVR (to values 36% below basal) and calf vascular resistance (CVR), as well as increases in cardiac output. Healthy pregnant women responded to NA with similar increases in blood-pressure, but this was due to stroke volume-dependent increases in cardiac output (11%) and not due to vasoconstriction. ADR-induced vasodilatation was attenuated in this group. Cardiac responses to ADR were unaffected by pregnancy. PIH patients demonstrated an enhanced systolic blood-pressure response to NA (19% increase vs 7-8% in the other groups) due to the combined effects of vasoconstriction (11% increase in SVR) and an essentially unchanged cardiac output. ADR-induced decreases in CVR and diastolic blood-pressure were similar to those found in the non-pregnant group. Increases in heart rate were less pronounced, but cardiac output increased as normal. These results indicate that normal pregnancy is associated with attenuated vascular responses to circulating catecholamines. PIH patients do not seem to have undergone this normal adaptation of the vascular system to pregnancy.

Blood Pressure↗
PubMed1982

Labetalol, a combined alpha- and beta-blocker, in hypertension of pregnancy.

Labetalol was given to women with hypertension of pregnancy in their last trimester to study its acute effect on circulation and metabolism. Seven women were given 50 mg labetalol i v. There was a significant decrease of blood pressure from a mean of 143/101 +/- 4/2 (SEM) to 127/88 +/- 5/2 mm Hg. Maternal heart rate fell significantly from 77 +/- 5 to 68 +/- 3 beats per min. These changes persisted during a three-hour observation period. The hypotensive response was accompanied by a significant increase in plasma noradrenaline from 1.54 +/- 0.16 to 2.37 +/- 0.41 nmol/l, suggesting sympathetic activation. Plasma cyclic AMP, which is increased by beta 2-adrenoceptor stimulation, was significantly elevated after labetalol. This supports the hypothesis of partial beta-agonist activity of labetalol. Lipid metabolism, as judged from measurements of plasma FFA, glycerol and 3-hydroxybuturic acid, showed little change. The acute effect of labetalol on uteroplacental blood flow was determined in eight women with pregnancy hypertension using a gammacamera on line with a computer. 0.5 mCi indium-113m was given i v before and 30 min after labetalol was administered i v in a dose of 1 mg per kg body weight. After the injections of indium-113m, serial scintigrams were recorded during 10 s periods for 240 s. By computerized summation of the scintigrams, an image was obtained in which the placenta could be outlined for time-activity analysis of the isotope accumulation curve. From this curve a uteroplacental blood flow index could be calculated. Labetalol induced a significant drop of mean arterial blood pressure from 114 +/- mm Hg to 100 +/- 3 mm Hg after 30 min in this group of women. However, the uteroplacental blood flow index did not change. As we have earlier shown with this technique that uteroplacental blood flow can be severely impaired in hypertension of pregnancy, the finding of substained uteroplacental blood flow simultaneously with a decrease in blood pressure should be of clinical importance. Taken together with other studies of clinical effects, these results indicate that labetalol is useful in the treatment of hypertension of pregnancy.

Adult↗
PubMed1982

Maternal kinetics and transplacental passage of pethidine during labour.

1 Pethidine is commonly used in single doses as an analgesic in obstetrics. Plasma concentration-time profiles of pethidine after intramuscular administration of 1.5 mg/kg body weight to 16 pregnant women during labour were investigated. There was only a two-fold variation in peak plasma concentration (300-650 ng/ml). The mean (+/- s.d.) value of the apparent plasma half-life of pethidine was 3.4 (+/- 1.0) h which is not different from that in healthy controls. norpethidine plasma levels were not measurable (less than 10 ng/ml). 2 The placental transfer transfer of pethidine was studied at delivery in samples from the umbilical cord vessels and from a maternal peripheral vein. In another 14 patients serial determinations of pethidine concentration were made in foetal scalp blood and maternal venous blood simultaneously during the different stages of labour. The foeto-maternal drug ratio varied between 0.35 and 1.5 with a positive correlation between ratio and dose delivery time interval. The concentration of pethidine in umbilical cord plasma or blood varied between 60 and 400 ng/ml with dose-delivery time intervals of 30 min to 10.5 h. The foetal concentration of pethidine reached a peak-plateau value between 1-5 h after dose.

Female↗
PubMed1981

Circulatory and metabolic effects of a combined alpha- and beta-adrenoceptor blocker (labetalol) in hypertension of pregnancy.

1 Seven women with hypertension of pregnancy were given the combined alpha- and beta-adrenoceptor blocking drug labetalol (50 mg i.v.) in their last trimester. Acute effects were studied for 3 h after administration. 2 Systolic and diastolic blood pressures were significantly reduced from 143 +/- 4 (s.e. mean) to 127 +/- 5 mmHg and from 101 +/- 2 to 88 +/- 2 mmHg, respectively. Maternal heart rate fell significantly from 77 +/- 5 to 68 +/- 3 beats/min. The changes remained during the 3 h of observation. Foetal heart rate was not affected. No side-effects were encountered. 3 Plasma noradrenaline increased significantly from 1.54 +/- 0.16 to a peak value of 2.37 +/- 0.41 nmol/l suggesting sympathetic activation following labetalol. Plasma adrenaline levels were essentially unchanged. Plasma glucose, insulin and C-peptide showed only minor changes. No major effects on lipid metabolism were seen except a significant fall of nonesterified fatty acids at 60 min. Plasma cyclic AMP increased significantly throughout the observation period, perhaps indicating beta-adrenoceptor agonist activity of labetalol. 4 The effectiveness of labetalol as an acute hypertensive agent together with apparent absence of metabolic disturbances and other side-effects makes it an interesting drug for the treatment of hypertension during pregnancy.

Blood Pressure↗
PubMed1981

Preterm breech delivery. Early and late complications.

One hundred and ten singleton breech infants with a birth-weight less than 2 500 g have been delivered at Huddinge University Hospital during the years 1972-78. The cesarean section rate was 30.1 per cent. Vaginal and abdominal deliveries were compared with regard to perinatal mortality and asphyxial morbidity at birth. All infants born with reduced Apgar scores or traumatic birth injuries have been followed up. During a 6-year period 3 children born with low Apgar scores were found to have persistent sequelae. Two of these were considered to relate to the delivery. We conclude that cesarean section is of benefit for infants weighing 1 000-1 500 g. However, it is doubtful if abdominal delivery is of benefit for the fetus weighing 1 500-2 500 g. A high congenital anomaly rate (13.6 per cent) was found.

Apgar Score↗
PubMed1981

Term breech delivery. Early and late complications.

Three hundred and sixty-six consecutive singleton breech presentations were analyzed for clinical factors associated with fetal complications related to vaginal delivery, and for the impact of different cesarean section rates on the incidence of fetal complications. The condition at birth of the vaginally delivered (243 cases) infants was found to correlate with maternal pre-pregnancy weight, and size of the fetal head. During the period of study the cesarean section rate changed from approximately 20 per cent of term breech presentations at the beginning to almost 50 per cent at its end. This was accompanied by a decrease in the traumatic morbidity. However, at follow-up only a small minority of those registered were found to be significantly affected. The fetal asphyxia rate was not influenced by the increased cesarean section rate. At follow-up one of 33 infants born asphyxiated showed late psychomotor development.

Asphyxia Neonatorum↗
PubMed1978

Role of blood and fibrinogen in development of intraperitoneal adhesions in rats.

One hundred and twenty rats were divided into six groups and laparotomized. In three of the groups the cecum was left intact. In one of these groups the cecum was only lifted up through the abdominal incision and then replaced in the abdominal cavity. In another group the intact cecum was bathed with a certain amount of blood from the animal's tail. In the third group the uninjured cecum was covered with fibrinogen in an amount equivalent to that in the blood used in the other group. In the remaining three groups the cecum was traumatized in a standardized way. In one of these groups the injured cecum was left untreated. In another group the traumatized cecum was bathed in homologous blood and in the third group the injured cecum was treated with fibrinogen as described above. Two weeks later the rats were killed and the number and quality of the intra-abdominal adhesions were studied. The findings in the present investigation indicate that neither blood nor fibrinogen per se induced adhesions to the serosa. On the contrary, a defect in the serosa initiated the formation of adhesions.

Animals↗
PubMed1978

Surgicel--an absorbable hemostatic material--in prevention of peritoneal adhesions in rats.

Forty rats were laparotomized and subjected to a standardized cecal trauma. In half the number of the rats, the injured cecum was embedded in oxidized regenerated cellulose (Surgicel). In the remaining 20 rats, which served as controls, the cecum was left uncovered. The rats were sacrificed at 14 days after the operation and examined for intraperitoneal adhesions. Adhesions were significantly (p less than 0.001) less common in the group treated with oxidized regenerated cellulose. In a separate series eight rats were used for histological examination of the traumatized cecal wall. No macroscopic residuum of the implant was seen after one or two weeks. However, the histological examination demonstrated small remnants surrounded by ingrowing fibroblasts and inflammatory cells.

Absorption↗
PubMedDate not supplied

The role of endogenous endothelin in the regulation of uteroplacental and renal blood flow during pregnancy in conscious rats.

Advancing pregnancy is characterized by a ten-fold increase in uterine blood flow and a 50 per cent increase in renal blood flow. To evaluate the involvement of endogenous endothelin (ET) in these haemodynamic changes the effect of bosentan, an ETA/B receptor antagonist, on uteroplacental and renal blood flow was studied in awake pregnant Sprague-Dawley rats. Regional blood flows were measured using microsphere technique immediately prior to and 30 min after bosentan administration (20 mg/kg i.v.). Four groups of animals (term: 23 days) were included: bosentan was administered to ten rats at gestation day (GD) 19 and nine at GD 20-21. In addition, four rats at GD 19 and five animals at GD 20-21 received saline and served as control groups. Basal placental blood flow increased significantly from 19 days' gestation to 20-21 days. Basal myometrial blood flow did not change with gestational age. At gestation day 19 bosentan increased placental and myometrial blood flow significantly (80 per cent and 43 per cent, respectively, P<0.05). This effect was not observed at gestation days 20-21. Renal blood flow did not change in response to bosentan at GD 19 but decreased by 20 per cent at GD 20-21 (P<0.01). In conclusion, in the awake pregnant rat there is a significant endogenous ET dependent vasoconstrictor tone in the uteroplacental vessels that diminishes towards term. We speculate that this change in responsiveness to endogenous ET contribute to the increase in placental blood flow in late gestation.

Animals↗