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.

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.

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.

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.

Oral contraception in diabetic women. Diabetes control, serum and high density lipoprotein lipids during low-dose progestogen, combined oestrogen/progestogen and non-hormonal contraception

Thirtyeight women with insulin-dependent diabetes were randomly allocated to contraception with either a progestogen only (Lynestrenol 0.5 mg daily) (LYN), a combined oral contraceptive (OC) (Ethinyl oestradiol 50 μg + Lynestrenol 2.5 mg) (EE + LYN) or a non-hormonal intrauterine device (IUD). Diabetes control (i.e. insulin dosage, blood and urinary glucose and body weight) and the lipid concentration in serum and in high density lipoprotein (HDL) were assessed before and during six months use of the respective contraceptives.

In the LYN group urinary glucose excretion increased 10% in spite of unchanged blood glucose, body weight and insulin requirement. All serum lipids decreased; triglycerides by 40% (P < 0.01), cholesterol by 13% (P < 0.01) and phospholipids by 12% (P = 0.06), without alteration of HDL lipids. In the group using combined OC (EE + LYN) the insulin requirement increased by 7% (P < 0.01) without any change in body weight or blood and urinary glucose. Serum as well as HDL lipids remained unchanged. In the IUD group neither diabetes control nor serum or HDL lipids were altered.

It is concluded that in insulin-dependent diabetics the progestogen (LYN) has little influence on diabetes control but has a marked, though probably not adverse, effect on lipid metabolism. The combined OC (EE + LYN) may impair glucose homeostasis slightly but has little influence on serum or HDL lipids. These findings seem to differ from those obtained in non-diabetics during administration of contraceptive steroids and these differences suggest that absence of endogenous insulin production enhances the effects of progestogen and reduces the effects of synthetic oestrogens on lipid metabolism.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Anesthesia for cesarean section II: effects of the induction-delivery interval on the respiratory adaptation of the newborn in elective cesarean section

Ten healthy mothers and their infants were studied in connection with elective cesarean section. Anesthesia was induced with 250-300 mg hexobarbitone followed by 100 mg succinylcholine for endotracheal intubation. The surgeon started the operation when the eyelid reflex disappeared, and delivered the baby as quickly as possible. Mean induction-delivery (I-D) interval was 2 min 45 s. Anesthesia was then deepened with further barbiturate, diazepam and methoxyflurane, and alcuronium used as muscle relaxant. The respiratory adaptation of the infant was studied by blood gas and acid-base measurements in repeated arterial samples during the first three hours of life. The mothers were interviewed after 3-12 months. A comparison was made with another barbiturate group with a longer I-D interval (x = 9 min 10 s). The present material showed initially higher PaO2 lower PaCO2, higher pH and less base deficit (BD), which relfected the maternal state at delivery. After 10-30 min, the results approached equivalence, though the babies in the short I-D group showed a tendency toward normalization of metabolic acidosis earlier. At the interviews, two mothers complained of pain during skin incision, and two of nightmares. Anesthesia with barbiturate for cesarean section with the I-D intervals studied in both groups allowed good respiratory adaptation in the infants. There is, neverless, the need for an adequate period of time between induction and the start of the operation in order to minimize the risk for maternal awareness.