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Biomedical subjects

K Karlsson

Publications and source records attributed to K Karlsson.

At least 127 records · Page 7Linked to original sources
PubMed1983

Sound levels recorded within the symphony orchestra and risk criteria for hearing loss.

Investigations into noise-induced hearing loss should consist of two parts: a mapping of the sound environment and a charting of hearing loss. This paper is the first part of such an investigation: a mapping of sound levels and sound spectra within the symphony orchestra. It was found that 'heavy' symphonic music exceeds the permitted dose for industrial noise equivalent to 85 dB(A) for a full working week. The permitted noise dose is reached for 'heavy' music after a working time of 10 hours per week in 'exposed' positions, such as in front of trumpets, and after 25 hours in 'normal' positions. A simple method to estimate the 'noise' exposure in equivalent sound level for combination of different sorts of music has been developed.

Hearing Loss, Noise-Induced↗
PubMed1983

Hemodynamic changes after chronic pindolol administration in pregnant renal hypertensive rats.

The aim of the present study on pregnant renal hypertensive rats was to investigate the effects on central hemodynamics and uteroplacental blood flow after chronic administration of pindolol, a nonspecific beta-adrenergic receptor blocking agent with intrinsic beta-stimulatory effect. Renal hypertension was induced by partial clamping of both renal arteries four weeks before pregnancy. Pindolol was administered with the food during the entire pregnancy period. Two to four days before expected delivery mean arterial pressure, heart rate, cardiac output, (dye-dilution technique) and utero-placental blood supply (microsphere technique) were determined. The chronic pindolol treatment reduced heart rate by 25 per cent while both mean arterial pressure and cardiac output remained unchanged. However, blood flow to uterus and placentae was reduced by 43 and 64 per cent, respectively, after pindolol treatment. Clinical as well as experimental studies (15, 16) demonstrate a reduced utero-placental blood supply when pregnancies are complicated by hypertension. As pregnancies with severe hypertension are associated with an increased frequency of intrauterine growth retardation and intrauterine asphyxia the present results indicate that the combination of hypertension and long-term treatment with beta-blockers might reduce utero-placental blood flow enough as to seriously interfere with fetal oxygen supply thereby increasing the risk of intra- and extra-uterine asphyxia.

Animals↗
PubMed1983

The effect of pregnancy on heart size and blood pressure in renal hypertensive rats.

The main purpose of this study on rats was to examine the effect of pregnancy on experimental renal hypertension and cardiac size. Renal hypertension in the rats (RHR) was induced by standardized clamping of the left renal artery early in pregnancy (SRHR) or 4 weeks before mating (ERHR). As controls served non-pregnant RHR with the duration of hypertension matched to each above mentioned group, as well as non-pregnant and pregnant normotensive rats. Only 16% of the rats with renal artery clamping early in pregnancy (SRHR) developed hypertension in contrast to 41% of similarly operated non-pregnant rats and 56% of ERHR decreased their blood pressure to normal levels during pregnancy. Concerning left ventricular heart weight there was a slight increase in left ventricular weight during normal pregnancy in spite of a significantly reduced blood pressure. In both SRHR and ERHR an increased left ventricular heart weight was noticed during pregnancy even when arterial pressure was not increased. The present results suggest an antihypertensive effect of pregnancy and the existence of "trophic" influences and/or a volume induced adaptation of the heart causing an increased myocardial mass which is associated with pregnancy and partly independent of blood pressure influences.

Animals↗
PubMed1982

Cerebral arterio-venous difference for hypoxanthine and lactate during graded asphyxia in the fetal lamb.

Hypoxanthine (HX) and lactate are degradation products from energy-rich intracellular substrates (ATP and glycogen), and their concentration will increase during anaerobic conditions, such as fetal asphyxia. In this study the accumulation of the two metabolites in blood during asphyxia was studied in 7 acutely exteriorized fetal lambs. The arterio-venous difference of HX and lactate over the brain was related to the function of the fetal brain as reflected by the somato-sensory evoked electroencephalogram potentials (SEP). Increased concentrations of HX in plasma and lactate in blood occurred simultaneously with deterioration of the SEP and the 3 variables correlate highly significantly. During normoxia, a net cerebral influx was found for HX, which in combination with severe asphyxia gradually changed to a net efflux. A linear correlation was found between the cerebral arterio-venous differences of HX and the impairment of the SEP. No such correlation existed for lactate. The results suggest, that the fetal brain has a high threshold for degrading its energy-rich intracellular purines.

Animals↗
PubMed1982

Blood flow of the reproductive system in renal hypertensive rats during pregnancy.

An experimental study on pregnant rats was undertaken to explore whether renal hypertension interferes with uteroplacental blood supply and fetal weight. Renal hypertension was induced by standardized clamping of the left renal artery. Two days before expected delivery, blood flow to the reproductive organs was determined by microsphere technique in normal control rats, rats with short-standing renal hypertension induced early in pregnancy, and rats with established renal hypertension induced 4 weeks before pregnancy. Myometrial and placental blood supply was considerably reduced in renal hypertensive rats compared to that in normotensive pregnant rats, with the reduction in placental blood flow being as much as 68% in rats with established renal hypertension. Nevertheless, there was no reduction in fetal weights, placental weights, or number of fetuses in the litters. These findings suggest that the nutritional blood supply of the placenta normally has a considerable overcapacity, perhaps a necessary safety margin so that the fetus can manage the circulatory demands associated with delivery. If hypertension causes intrauterine growth retardation only by means of reduced placental blood flow, this reduction in flow obviously must be considerable.

Animals↗
PubMed1982

A scoring system for antenatal identification of fetal growth retardation.

A scoring system for selection of pregnancies at risk of intrauterine growth retardation (IUGR) is presented. It is based on eight weighted items which include information from previous pregnancies and from the current one including the increment of fundal height and of maternal weight. With a risk population of 7% all IUGR infants were included. The IUGR infants constituted 34% of the risk group.

Birth Weight↗
PubMed1982

Immuno-histochemical localization of myoglobin in human muscle tissue and embryonal and alveolar rhabdomyosarcoma.

An immuno-histochemical investigation of the presence and localization of myoglobin was performed on cardiac and skeletal muscle tissue and on 9 embryonal and 9 alveolar rhabdomyosarcomas, utilizing an immunoperoxidase technique. Cardiac muscle fibres were evenly stained whereas staining of skeletal muscle fibres varied, giving a mosaic-like pattern. Of the fixatives used (4 percent formaldehyde, 4 percent paraformaldehyde, formaldehyde-glutaraldehyde, and Bouin's fixative), 4 percent formaldehyde gave the most prominent staining; short fixation-time slightly increased the staining intensity. All the 9 embryonal and 9 alveolar rhabdomyosarcomas contained positively-stained tumour cells. The number of cells positively-stained and the intensity of the staining varied with differentiation: the most differentiated rhabdomyoblasts stained most intensely. However, also many poorly-differentiated tumour cells in highly cellular areas were positive. Myoglobin is considered a suitable marker of rhabdomyoblastic differentiation, thus the method used in this study may be valuable in the diagnosis.

Cell Differentiation↗
PubMed1982

Metabolic studies in gestational diabetic women during contraceptive treatment: effects on glucose tolerance and fatty acid composition of serum lipids.

Intravenous glucose tolerance tests (IVGTT) with simultaneous assessment of plasma insulin and analyses of the fatty acid composition of serum lecithin and cholesterol esters were performed in 11 women with previous gestational diabetes before and repeatedly during 6 months' administration of a low-dose progesterone (lynestrenol = LYN). 8 of these women were also followed in an identical manner during 6 months of nonhormonal contraception (intrauterine device = IUD) and additionally 6 of these women were followed also during the use of a combined oral contraceptive (OC) (ethinyl estradiol + lynestrenol - EE + LYN). LYN did not alter the IVGTT or plasma insulin but decreased the proportion of polyunsaturated fatty acids (PUFA) in serum lecithin (p less than 0.01) and cholesterol esters (p less than 0.01) where oleic acid was reciprocally increased (p less than 0.05). After 6 months' use of IUD, on the other hand, the k value of IVGTT increased by 45% (p less than 0.01) without significant changes in plasma insulin. In both lecithin and cholesterol ester PUFA increased (p less than 0.05) and cholesterol ester oleate decreased (p less than 0.01); i.e., virtually the reversal of the changes seen during LYN administration. The combined OC, EE + LYN, caused a decrease in the k value by 27% (p less than 0.05) which was apparent even when compared to the effects of LYN alone. EE + LYN also increased (p less than 0.05) lecithin palmitate and decreased stearate (p less than 0.05) and had a concomitant tendency to lower PUFA and increase oleic acid in both lecithin and cholesterol esters. These results indicate that LYN has little influence on the glucose tolerance in women predisposed to diabetes but may provide poorer conditions for dietary treatment of subclinical diabetes than do nonhormonal IUDs. The combined CO, EE + LYN, on the other hand, promptly diminishes glucose tolerance and may also have an unfavorable influence on liver metabolism.

Adult↗
PubMed1982

Metabolic studies in women with previous gestational diabetes during contraceptive treatment: effects on serum lipids and high density lipoproteins.

Triglycerides, cholesterol and phospholipids in serum and high density lipoproteins (HDL) were assessed in 11 women with previous gestational diabetes before and repeatedly during 6 months of low dose progestogen (lynoestrenol = LYN) contraceptive administration. Eight of these women also were followed in an identical manner during non-hormonal contraception (IUD) and 6 of them during combined oral contraceptive administration (EE + LYN). During the use of IUD or LYN administration neither serum nor HDL lipids changed. The combined OC, EE + LYN, increased serum triglycerides progressively: 73% (P less than 0.01) after 6 months concomitant with a 100%-increment of HDL triglycerides (P less than 0.01) HDL-cholesterol and -phospholipids were not consistently changed. The EE + LYN induced alterations differed from the effects of LYN alone (P less than 0.01). During the use of IUD or LYN administration neither serum nor HDL lipids changed. The combined OC, EE + LYN, increased serum triglycerides progressively: 73% (P less than 0.01) after 6 months concomitant with a 100%-increment of HDL triglycerides (P less than 0.01). HDL-cholesterol and -phospholipids were not consistently changed. The EE + LYN induced alterations differed from the effects of LYN alone (P less than 0.01). These results suggest that low dose progestogens, such as LYN, could be considered as contraceptive alternatives in women with gestational diabetes. However, combined OC should be avoided in these patients. The present findings differ from those obtained in insulin-dependent diabetics and suggest that a diabetic prediposition enhances the effects of synthetic oestrogens and/or diminishes some of the effects of progestogens on lipid metabolism.

Adult↗
PubMed1982

alpha 2-Antiplasmin and alpha 2-macroglobulin--the main inhibitors of fibrinolysis--during the menstrual cycle, pregnancy, delivery, and treatment with oral contraceptives.

alpha 2-Antiplasmin and alpha 2-macroglobulin have been studied during the menstrual cycle, pregnancy and parturition in healthy women, and during use of various types of contraception in both healthy and diabetic women, and compared with a reference group of healthy men and women. alpha 2-Antiplasmin showed a slight sex difference, with higher values in women. The luteal phase of the menstrual cycle showed slightly higher values than the other phases. alpha 2-Antiplasmin increased during pregnancy, decreased (probably due to consumption) during labor and increased again in the puerperium. Treatment with neither combined contraceptive pills nor low dose progestogen pills gave any changes in alpha 2-antiplasmin. alpha 2-Macroglobulin showed low values during menstruation. The increase during pregnancy and treatment with combined contraceptive pills is in accordance with earlier findings. It is concluded that synthesis and metabolism of alpha 2-antiplasmin are under hormonal influence. The role of alpha 2-antiplasmin in the decreased fibrinolysis in pregnancy is discussed.

Adolescent↗
PubMed1982

Changes in central hemodynamics during pregnancy in renal hypertensive rats.

Central hemodynamics during late pregnancy were studied in normotensive rats and in rats with short-standing and "established" renal hypertension. In normal pregnancy cardiac output was increased 33%, due to increased stroke volume while mean arterial pressure and systemic resistance were reduced 17 and 40% respectively. The same changes, though less pronounced were noted during pregnancy in rats with short-standing renal hypertension, where cardiac output was increased 31%, due to equal increases in heart rate and stroke volume while systemic resistance was reduced only 27%. By contrast, no significant cardiac output increase, nor any resistance reduction was noted during pregnancy in rats with established hypertension. Thus, renal hypertension in rats seems to interfere with circulation during pregnancy mainly by restricting both the cardiac output increase and the systemic resistance reduction seen during normal pregnancy. This restriction seems to be more pronounced the longer the duration of hypertension.

Animals↗
PubMed1982

Oral contraception in diabetic women. A cross-over study on serum and high density lipoprotein (HDL) lipids and diabetes control during progestogen and combined estrogen/progestogen contraception.

Twenty-three young women with insulin-dependent diabetes were randomly allocated to contraceptive treatment with either a progestogen only (Lynestrenol 0.5 mg) (LYN) or a combined oral contraceptive (OC) (ethinyl estradiol 50 micrograms + lynestrenol 2.5 micrograms) (EE + LYN). After six months treatment the medication was withdrawn for at least two months, after which the patients were placed on the other preparation. Diabetes control and serum and high density lipoprotein (HDL) lipids were assessed before and after 1, 3 and 6 months of treatment. Low-dose LYN administration did not alter the insulin requirement, blood glucose or body weight while the combined EE + LYN treatment increased the insulin requirement (p less than 0.01) without altering blood glucose or body weight. Low-dose LYN reduced serum triglycerides (p less than 0.001), serum cholesterol (p less than 0.001) and serum phospholipids (p less than 0.01) without affecting HDL lipids, while EE + LYN gave an inconsistent increase in serum triglycerides (p less than 0.01) but no change in HDL lipids. These findings confirm our earlier results and we conclude that EE + LYN influences diabetes control slightly more (although still not seriously) than the low-dose LYN. It is suggested that insulin-dependent diabetics (in contrast to non-diabetics) are more sensitive to the influence of 19-norprogestogens than to alkylated estrogens, with respect to lipid metabolism.

Adolescent↗
PubMed1982

Cardiac output in normal pregnancy measured by impedance cardiography.

Impedance cardiography was used to study cardiodynamic changes throughout normal pregnancy. Stroke volume, heart rate and cardiac output were determined in fourteen normal primigravidae from early pregnancy until 6-25 weeks after delivery. To elucidate the influence of the patient's position on cardiac output, measurements were made in the supine as well as in the left and right lateral positions. Stroke volume and cardiac output increased up to the 28th week of pregnancy and then decreased during late pregnancy. These changes seemed to be independent of the patient's position. After delivery a further reduction in cardiac output due to a significant decrease in heart rate was found. No significant differences in cardiac output were found between right and left lateral position. However, during pregnancy as well as after delivery, cardiac output measured by impedance cardiography was significantly higher in the supine position than in the lateral positions. Thus, the impedance method does not seem to be reliable in measuring absolute values of stroke volume and cardiac output but may be used for relative measurements during pregnancy.

Adult↗
PubMed1981

Effects on rat fetuses of intrauterine injections of insulin.

The effects on rat fetuses of a single intrauterine injection of long-acting insulin with respect to length, body and organ weights, total lipids, phospholipids, cholesterol, neutral fat, total nitrogen and water content were investigated. At the age of 498 hours the fetuses were injected in utero with 2 IU of long-acting insulin or a control solution. Twenty-four hours after the injections the insulin-treated fetuses weighed about 10 per cent more than the control fetuses, 5.32 +/- 0.05 g (75 fetuses) and 4.85 +/- 0.05 (73 fetuses) respectively (p less than 0.001). The body lengths were 54.1 +/- 0.2 mm and 52.9 +/- 0.2 mm respectively (p less than 0.001). The insulin-treated fetuses had higher organ weights and higher content of total lipids, phospholipids and neutral fat. The amount of total lipids was higher in insulin-treated fetuses even after taking into account differences in body weight, suggesting that the insulin-treated fetuses were obese. The finding of significantly lower water content in insulin-treated fetuses at equal body weight is consistent with the higher fat content. There was no increase in total nitrogen or length in the fetuses in the insulin-treated group compared to control fetuses at equal body weight indicating that the administered insulin mobilized maternal proteins and that protein, as well as length, increased proportionately to overweight. For quantitative analysis of morphological and biochemical variables dependent upon body weight, as in this investigation, multivariate analysis is indispensable.

Animals↗
PubMed1981

Changes in hypoxanthine and lactate during and after hypoxia in the fetal sheep with chronically-implanted vascular catheters.

The effect of intra-uterine hypoxia on the hypoxanthine and lactate concentration in fetal sheep with catheters chronically implanted was investigated. Experiments were conducted on five fetuses. Sixty-four blood samples from nine hypoxic and recovery periods were analysed. A significant increase of hypoxanthine and lactate occurred in parallel with the fall of arterial oxygen saturation (SaO2) and arterial oxygen pressure (PaO2) during the first 20 min of hypoxia. The elevations in plasma hypoxanthine and lactate were significantly greater during more severe hypoxia than mild hypoxia, as judged from the amount of low oxygen gas mixture given to the ewe (7 or 9%). There were no difference in PaO2 and only minor difference in SaO2 between the two groups. The increase in lactate over 20 min was the same throughout the one-hour period of hypoxia, while the increase of hypoxanthine was less pronounced at the end of the period. This might be due to the fact that hypoxanthine was cleared from fetal plasma at a fairly rapid rate, half of the excess concentration being eliminated after 25 +/- 21 min compared to 85 +/- 47 min for lactate in six experiments post hypoxia. Linear regression analysis revealed a highly significant correlation between hypoxanthine and SaO2, pH and lactate (P less than 0.001). These three variables explained 77% of the variance of hypoxanthine, when calculated by multiple regression analysis.

Animals↗