The effects of thimerosal and cyclopiazonic acid on the Ca(2+)-pumps from rat cerebellum microsomes.
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Biomedical subjects
Publications and source records attributed to L Sayers.
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The concentration of melatonin in maternal peripheral plasma was measured during late pregnancy, term and pre-term labour. There was a small increase in the mean concentration of melatonin during labour which was significant in term labour. Umbilical arterial and venous plasma, whether obtained at term, after spontaneous vaginal delivery or at Caesarean section, contained significantly greater concentrations of melatonin than maternal plasma. A significant arterio-venous difference was demonstrated for both groups of umbilical samples with raised venous levels after spontaneous vaginal delivery but higher arterial levels at Caesarean section.
Mean serum concentrations of oestradiol-17beta, oestrone, and oestrone sulphate in postmenopausal women were the same when measured up to six hours after treatment with either piperazine oestrone sulphate 1.5 mg or oestradiol valerate 2 mg. Maximum concentrations of oestradiol were less than those of oestrone, but oestrone sulphate reached concentrations about 30 times higher than those of oestrone. The rapid conversion of oestradiol valerate to oestrone and oestrone sulphate does not support the suggestion that in menopausal women oestradiol is less likely to be associated with a risk of endometrial carcinoma than oestrone sulphate, since the two preparations appear to become identical after ingestion.
Concentrations of melatonin have been measured in amniotic fluid obtained during late pregnancy and labour. Samples obtained by amniotomy during labour contained higher concentrations of melatonin than samples taken at amniotomy for the induction of labour. Amniotic fluid obtained by amniocentesis in late pregnancy contained lower concentrations of melatonin than amniotic fluid obtained by amniotomy. The implications of these findings are discussed in relation to pineal influences on parturition.
The concentration of betamethasone has been measured in maternal peripheral plasma, umbilical cord artery and vein, and amniotic fluid following maternal administration of betamethasone phosphate and betamethasone acetate on 3 consecutive days. Betamethasone was measured by radioimmunoassay following column chromatography. The findings show that betamethasone is transferred across the human placenta, circulates in the fetus and appears in amniotic fluid. During the 3 days after the start of treatment, levels of the betamethasone were similar in maternal and umbilical cord blood and in amniotic fluid. Thereafter, although levels in the mother were measurable for up to 7 days after the initial injection, the drug was detected in the cord plasma of only one baby. In vitro incubation studies of human placental tissue with 3H betamethasone identified 11-keto betamethasone as the major metabolite of betamethasone.
Maternal plasma levels of cortisol were measured serially by radioimmunoassay in two groups of 12 patients during induced labour and in the puerperium. One group was given continuous extradural analgesia throughout labour, the other group received pethidine and promazine in response to pain. Pre-induction cortisol levels were significantly higher in patients who were to have extradural analgesia but the percentage increase in plasma cortisol during labour was considerably less than in patients with parenteral analgesia; in second stage labour, mean cortisol levels were the same in the two groups. This study suggests that patients who had chosen to have extradural analgesia may have been more anxious before labour than the other patients but continuous, extradural analgesia suppressed to some extent the percentage increase in mean cortisol levels found during labour in patients given parenteral analgesia. In the puerperium, there was no difference in mean cortisol levels in the two groups.
The coagulation system was studied in twenty-seven patients undergoing second-trimester abortion induced by intra-amniotic prostaglandin (P.G.) E2 alone and in combination with a hypertonic solution of urea or glucose. Changes consistent with intravascular coagulation, namely a rise in fibrin degradation products and a fall in plasma-fibrinogen and platelet-count, were observed in those patients treated using P.G.E2 with hypertonic urea. Similar but less pronounced changes were found in the group treated using P.G.E2 with hypertonic glucose. In patients treated with P.G.E2 alone no changes suggestive of intravascular coagulation were detected. One patient treated using P.G.E2 with hypertonic urea who did not abort for 26 hours demonstrated changes indicative of a pronounced degree of disseminated intravascular coagulation. These findings show that when abortion is induced using P.G.E2 and a hypertonic solution, particularly hypertonic urea, disseminated intravascular coagulation can occur as a result of a hypertonic agent being used.
1. In vitro, the lungs of male Wistar rats, 220-230 g, removed heart substance (HS) from saline perfusates. HS could not be recovered by subsequent perfusion with HS free solution.2. A maximum rate of HS-uptake, 8.5 ng biological equivalents of 18-monoacetate of D-aldosterone (18 MA)/min, was reached at a concentration of HS equivalent to 3.5 ng 18 MA/ml. at a flow of 6 ml./min.3. Uptake was not significantly affected by a fall in temperature from 38 to 18-20 degrees C or by reduction in P(CO) (2) to zero. Uptake was reduced by anoxia and was enhanced by decrease of pH from 7.4 to 6.6.4. 30% of the HS taken up by the lungs at 20 degrees C was recoverable: none of the HS taken up at 38 degrees C was recovered.5. Uptake of HS by binding is considered rate-limiting to the destruction of HS in the lungs.6. The concentrations of HS found in the pulmonary and carotid arterial blood of cats under chloralose anaesthesia, during haemorrhage, were biologically equivalent to 1098 +/- 38.7 and 169 +/- 13.4 ng 18 MA/100 ml. (means +/- S.E.) respectively, in four experiments.
Sun protection habits should begin early in life and be taught as part of routine preventive health care. Early teaching of parents aims to introduce an easily achieved means of sun protection with the goal of instilling these practices as habits in the parents and their young children. We developed a maternity nurse-led intervention for 187 mothers at newborn nurseries in Falmouth, Massachusetts, combining educational material and personal discussions. One year after the intervention we successfully contacted 73% of the mothers. Nearly 90% recalled the informational program and equal numbers stated that receiving educational materials in the newborn nursery was timely. Nearly two-thirds of mothers reported that this was the only sun protection information received from a provider in the past year.