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Biomedical subjects

K Karlsson

Publications and source records attributed to K Karlsson.

At least 145 records · Page 8Linked to original sources
PubMed1980

Early insulin response in latent gestational diabetes.

The intravenous glucose tolerance and glucose-stimulated early insulin response (EIR) were studied in late pregnancy and post partum in a reference (R) group of 9 women and in 18 women with latent gestational diabetes (LD), defined as a k-value of < 0.66/h and a normal fasting blood glucose concentration. During pregnancy, the LD group showed a lower EIR than the R group. However, the response ranged between normal and non-detectable. In the non-pregnant state, the EIR was the same in the two groups. The inability to increase the EIR during pregnancy wss most evident in women who even post partum had an abnormal glucose tolerance. In some women in the LD group, the EIR during pregnancy was even lower than in the non-pregnant state. The magnitude of the response in the non-pregnant state was not decisive of the capacity to increase the secretion during pregnancy. None of the women in the LD group developed manifest diabetes during pregnancy. They gave birth to children with normal birth weight, and no neonatal problems were registered except for one child with congenital heart malformation.

Adult↗
PubMed1980

Application and usefulness of enzyme immunoassay for diagnosis of Salmonella typhimurium infection.

An enzyme immunoassay for serogroup specific immunological diagnosis of salmonella infections has been developed. Antigens representing salmonella O-antigens 4 (serogroup B) and 9 (serogroup D) were prepared by periodate oxidation of phenol-water extracted lipopolysaccharides from S. typhimurium and S. enteritidis respectively. Applied for seroepidemiological studies of S. typhimurium infections such chemically modified antigens showed a superior specificity compared to native lipopolysaccharides. The antibody titres against O-antigen 4 measured by the enzyme-linked immunosorbent assay (ELISA) were detectable during the second week and increased during the first 3--4 weeks of S. typhimurium infection. High titres persisted for at least 2--3 months and in some cases for more than 3 years. For reliable serodiagnosis a significant increase of the titre between acute and convalescent samples is necessary . Determination of ratio between IgG and IgM antibody titres against the pathogen may, however, be used on single serum samples to indicate whether the observed antibody titre is of recent or longstanding origin.

Antibodies, Bacterial↗
PubMed1979

Circulatory changes during pregnancy in spontaneously and renal hypertensive rats.

1. Mean arterial pressure, heart rate, cardiac output (dye-dilution technique), stroke volume, total peripheral resistance (TPR), utero-placental blood supply (microsphere technique) and foetal weights were determined 2 days before expected birth in normotensive control (NC) rats, spontaneously hypertensive (SH) rats, rats with short-standing renal hypertension induced early in pregnancy and rats with established renal hypertension induced 4 weeks before pregnancy. Non-pregnant rats in comparable states served as controls. 2. In normal pregnancy cardiac output increased by 33% and blood pressure and TPR decreased by 17 and 38% respectively. The same principal changes were noted in SH rats and those with short-standing renal hypertension, but no changes were found in rats with established renal hypertension during pregnancy. 3. Myometrial and placental blood supply was lower in all hypertensive groups compared with NC rats, the reduction being 46 and 36% in SH rats and in rats with established renal hypertension as much as 74 and 68% respectively. 4. In SH rats foetal weights were reduced compared with NC rats, but despite the 68% reduction of placental blood flow in rats with established renal hypertension foetal weights were here unchanged.

Animals↗
PubMed1979

ECG-changes in the fetal lamb during asphyxia in relation to beta-adrenoceptor stimulation and blockade.

Progressive changes in the S-T interval of the fetal electrocardiogram (FECG) were studied in 14 lamb fetuses, acutely exteriorized and subjected to graded hypoxia. The aims of the study were to investigate whether beta-adrenoceptor stimulation and hypoxia exerted additive or potentiating effects on the FECG and several cardiovascular parameters and whether the hypoxic changes of the FECG could be blocked by beta-adrenoceptor blocking agents. The FECG changes were studied in order to correlate them with cardiovascular function, as measured by heart rate, mean arterial pressure, end diastolic pressure, maximum dP/dt and combined cardiac output, estimated by the thermodilution method, as well as with blood gases, acid base status, blood lactate and glucose. Injections of small doses (0.02 to 0.4 microg kg-1 min-1) of isoprenaline induced the same pattern of changes in the FECG as we have previously recorded during hypoxia. By increasing the isoprenaline dose an increase in the duration of the FECG changes and amplitude of the T-wave changes was obtained. Propranolol was found to completely abolish the FECG changes induced by isoprenaline, as well as by mild hypoxia. During severe hypoxia the FECG changes could not be abolished by propranolol. Our previous findings indicated that the hypoxic changes could be regarded as a sign of myocardial glycolysis. Thus, the present finding that even small doses of isoprenaline given to the fetus, initiates the same pattern of FECG changes corroborate this hypothesis.

Animals↗
PubMed1978

Neonatal electrocardiographic changes in relation to cardiotocographic changes.

Electrocardiograms (ECG) were made immediately after delivery in 28 infants with normal cardiotocographic patterns in labour and in 29 with abnormal patterns. Changes in the S-T segment and T-wave were quantified in a scoring system. High and peaked T-waves (high T/QRS-ratios) were significantly more common in the group with abnormal cardiotocographic patterns. The infants with ECG-changes also had significantly lower Apgar scores and more neonatal complications. The immediate postpartum ECG seems to be a useful indication of the accumulated hypoxic stress to which the child has been subjected in labour.

Apgar Score↗
PubMed1978

Measurement of cerebral blood flow in the fetal lamb with a note on the flow-distribution.

The cerebral blood flow was measured in the acutely exteriorized fetal lamb by 133Xenon washout and microsphere distribution techniques. The measurements were performed at different blood gas levels. Regional cerebral blood flow was calculated from the microsphere distribution for five different parts of the brain. This gave estimates for blood flow in both the grey and white matter of the hemispheres, which were in close agreement with the cerebral blood flow estimated by the 133Xe washout technique. The microsphere distribution shows that the fetal cerebral hemisphere has a low blood flow compared to the basel parts of the brain and that this difference is increased during hypoxia and hypercarbia.

Animals↗
PubMed1977

Differetial staining of glycosaminoglycans, utilizing bacterial chondroitinase and chondrosulphatase.

A histochemical method for the differentiation of glucosaminoglycans, utilizing bacterial chondroitinase ABC and chondro-4- and -6 sulphatases, and staining with Alcian blue, is presented. The method is applied on human tissues with known glucosaminoglycan content (ganglion cyst, umbilical cord, foetal cartilage, adult cartilage) and the results are compared with the results obtained by staining with Alcian blue at controlled pH levels, with or without prior digestion with bovine testicular hyaloronidase, and the Scott method, utilizing Alcian blue at varying concentrations of MgCl2. It is concluded that chondroitinase ABC digest chondroitin-4 and -6 sulphate and to some extent also hyaluronic acid and dermatan sulphate, but not heparin and keratosulphate.

Alcian Blue↗
PubMed1977

Quantification of fetal heart rate variability in relation to oxygenation in the sheep fetus.

Beat-to-beat variability has been suggested as a sensitive indication of fetal well-being. The suggestion originates from case reports of observed decrease in variability preceding clinical signs of fetal asphyxia and fetal death. Against this background a study was performed to evaluate possible changes in heart rate variability in relation to changes in fetal oxygenation. Chloralose-anesthetized sheep were used. Short-term hypoxia was produced without acidosis. The FECGs were recorded on magnetic tape and later analysed by scrutinizing each QRS complex prior to the trigger of a rate meter. The differential index (DI) described by Yeh and co-workers was chosen because it is easily computed and reflects the variability of coefficient of variation for two successive R-R intervals. In contrast to the generally held view of a progressive diminution of variability during the development of asphyxia, the variability was found to increase parallel with a decrease in fetal arterial PO2 determined on blood samples withdrawn at intervals and ranging between 26 and 10 mmHg. The correlation between variability and PO2 in the range below 8-10 mmHg is still to be determined.

Animals↗
PubMed1976

Anesthesia for cesarean section III: effects of epidural analgesia on the respiratory adaptation of the newborn in elective cesarean section.

A rise in fetal Paco2 was observed after elective cesarean section in patients anesthetized both with a barbiturate and with nitrous oxide/oxygen. Epidural analgesia seemed to be a good alternative in order to attain better blood gas values in the newborn infant. Fourteen healthy mothers and their infants were studied in connection with elective cesarean section. Epidural analgesia with plain bupivacaine 0.75% was used. Doses varied between 90 and 120 mg. The time between the epidural injection and delivery was around 50 min. In six cases the fetal heart rate was registered continuously. Most of the mothers were sedated with diazepam intravenously or fully anesthetized, after delivery. The mothers were interviewed later. The respiratory adaptation of the infants was studied by blood gas and acid-base measurements in repeated arterial samples during the first 3 hours of life. A comparison was made with a group previously studied, where general anesthesia with a barbiturate, nitrous oxide/oxygen was the method used. The present material showed no differences concerning Pao2 and Paco2 but clearly indicated a tendency towards an earlier normalization of the initial metabolic acidosis. Mothers showed a respiratory alkalosis which was overcompensated by the metabolic component. Maternal blood pressure falls were observed in four cases, and fetal effects could be detected. Although epidural analgesia has a more favorable effect upon the newborn's metabolic component, both the compared methods allow good respiratory adaptation provided they are used correctly. Mothers can be given the opportunity to choose between being conscious or asleep when their child is delivered.

Adaptation, Physiological↗
PubMed1976

Anesthesia for cesarean section IV: placental transfer and neonatal elimination of bupivacaine following epidural analgesia for elective cesarean section.

Epidural analgesia with bupivacaine was used for elective cesarean section, and repeated maternal and neonatal blood samples were collected over 24 h for calculation of drug concentration. A gas-chromatogrphic micro-method was used for the analysis. The aim of this investigation was to evaluate the placental transfer and the elimination rate of the drug. No signs of systemic toxicity were observed in any mother or child, despite relatively high blood concentrations. The fetal-maternal ratio of concentrations at delivery was higher than in previous studies, most probably due to the protein-binding characteristics of bupivacaine and the dosage used. The biological half-life of the rapid phase of elimination (alpha-phase) in the newborn was shorter than in the mother (P less than 0.002), indicating a more rapid distribution process. The half-life of the slow phase of elimination (beta-phase) in the newborn was of the same magnitude as in the mother, indicating that neonatal elimination processes of bupivacaine may be well developed at birth.

Adult↗
PubMed1976

Anesthesia for cesarean section V: effects of enflurane anesthesia on the respiratory adaptation of the newborn in elective cesarean section.

The new anesthetic inhalation agent, enflurane, is supposed to allow rapid induction and recovery. Experinece with this agent in obstetrics is limited. Enflurane was therefore studied in 14 pregnant women undergoing elective cesarean section. Its effects upon the respiratory adaptation of the newborn infants were followed during the first 3 hours, as judged by oxygen tensions and acid-base balance measurements in serial neonatal arterial samples. Results were compared with those from a previously studied group of women anesthetized with a barbiturate and nitrous oxide-oxygen. There were no differences with respect to oxygen tension. Carbon dioxide values in the enflurane group were higher than those in the barbiturate group. In comparison with the barbiturate group the enflurane group of babies had lower BD values, which is a sign of a better metabolic state post-partum. Mothers anesthetized with enflurane were satisfied with the method, especially for the post-operative period.

Adaptation, Physiological↗