Severe hypertriglyceridaemia in Type 2 diabetes mellitus: beneficial effect of continuous insulin infusion

BACKGROUND

Severe hypertriglyceridaemia is a recognized complication of Type 2 diabetes mellitus (T2DM); however, there is no consensus on acute management despite the significant risk of developing associated complications such as acute pancreatitis and hyperviscosity syndrome.

AIM

To identify the association between hyperglycaemia and severe hypertriglyceridaemia in patients with T2DM and assess the effect of continuous insulin infusion therapy on serum triglyceride (TG) concentrations and report any adverse events associated with this therapeutic approach.

DESIGN

Retrospective review of case records.

METHODS

Patients with uncontrolled hyperglycaemia and severe hypertriglyceridaemia (serum TG > 15 mmol/l) treated with continuous intravenous insulin infusion between October 2008 and September 2009 were retrospectively evaluated (n = 15). Details recorded included demographics, admission details, lipid profiles, glycaemic control, serum amylase and adverse events. Patients receiving treatment-dose unfractionated heparin infusion were excluded.

RESULTS

Severe hypertriglyceridaemia is associated with hyperglycaemia in our heterogeneous group of patients with T2DM presenting with new-onset diabetes or established disease on pre-existing insulin or oral hypoglycaemic agents. Administration of continuous exogenous insulin not only achieved normoglycaemia but also dramatically corrected severe hypertriglyceridaemia in all patients (P = 0.001).

CONCLUSION

The administration of continuous insulin in patients with T2DM with severe hypertriglyceridaemia is a simple and safe method of significantly reducing the immediate risk associated with this metabolic complication and should be considered in any T2DM patient presenting with severe hypertriglyceridaemia and hyperglycaemia.

Comparison of AFP and beta-hCG levels in infiltrating duct mammary carcinoma at different stages of malignancy

In order to assess the likely clinical value of AFP and beta-hCG levels as markers of the extent of spread of infiltrating duct mammary carcinoma, we compared (Mann-Whitney U test) the immunoreactive tumour tissue concentrations of the respective antigens, measured by specific RIA, after mastectomy in Chinese women at stages I (n = 9), II (n = 13) and III (n = 7) with that of normal breast tissue (n = 11). Elevated concentrations of the oncofetal antigens were found at all stages of malignancy. The discovery of an hCG-like material in the extract of normal breast tissues indicates limited value of beta-hCG assay in mammary tumours. However, our findings generally suggest that measurement of the tumour tissue AFP levels warrant consideration as a useful biochemical marker for in-vitro evaluation of tumour spread at all stages of malignancy.

alpha-Fetoprotein levels in fullterm and very low birthweight infants

Plasma alpha-fetoprotein (alpha-FP) levels were determined in fullterm and very low birthweight (VLBW) infants in the first week of life and serially in a cohort of VLBW infants for the first 24 weeks after delivery. A rapid decline in alpha-FP levels was observed in both the fullterm and VLBW infants initially. Beyond 2 weeks of age, there was a gradual, linear decline until 6 weeks, followed by a more rapid period of decline from 6 to 16 weeks. The decline in the ensuing weeks demonstrated an asymptotic pattern. The half-life of alpha-FP was 7.5 days in the first week of life in both fullterm and preterm infants, 28.7 days from 2 to 6 weeks of life and 11.9 days from 6 to 16 weeks of life in VLBW infants.

Effect of indomethacin on the injection-abortion interval of 15(S) 15 methyl PGF2 alpha-induced mid-trimester abortions--a randomized study

There have been conflicting reports on the effect of non-steroidal anti-inflammatory drugs on the abortifacient effect of prostaglandins. The efficacy of intra-amniotic 1.5 mg 15(S) 15 methyl PGF2 alpha (15 me PGF2 alpha) in terminating mid-trimester pregnancy in 10 subjects has been compared with the effect of the same medication given to 10 others who had had indomethacin 25 mg and 50 mg orally three and one hour before the PG administration. In the subjects who had the PG analogue only the injection-abortion interval was 17.0 hours. This was significantly shorter (P less than 0.01) than in those who had also received indomethacin (25.4 hours).

Histopathology of the testes from male transsexuals on oestrogen therapy

This study was conducted to determine whether the histopathology of the testis of the male transsexual would throw light on the pathogenesis of male transsexualism. Histological sections of testicular tissues obtained at sex reassignment surgery from phenotypic male transsexuals (n = 10, age 21-33 years) with XY sex chromosome constitution were studied by light microscopy. The patients were diagnosed on clinical and psychiatric evidence and had been on oestrogen therapy for 6-13 years. The significant histological findings in the ten subjects were: (i) Focal or normal spermatogenic activity associated with normal Leydig cell population in three cases, and (ii) Total absence of spermatogenic activity associated with reduced Leydig cell population in seven cases. We suggest that the observed histological features are due to refractoriness to oestrogen, and the iatrogenic effects of oestrogen superimposed on normal or altered hypoathalamo-pituitary function.

A comparative study of peritoneal fluid concentrations of oestradiol-17 beta, progesterone, and testosterone in controls and in patients with endometriosis

To ascertain whether a cyclical variation exists in the steroid hormone concentration of the peritoneal fluid between controls and patients with endometriosis, we set out to measure the concentration of oestradiol--17 beta (E2), progesterone (P4), and testosterone (T) by specific radioimmunoassay in the peritoneal fluid of these 2 groups. Forty six patients (mean age, 30.1 +/- 6 years) with pelvic endometriosis and 32 control patients (mean age, 32.2 + 3.8 years) without endometriosis were studied. The significance of differences between groups was determined by the Mann-Whitney mu test. In the control group a significant rise in peritoneal fluid E2 (P = 0.017) and P4 (P = 0.048) levels was observed in the luteal phase compared to the follicular phase, but no such difference was noted in women with endometriosis. It is suggested that peritoneal fluid steroid hormone assays are not helpful in the evaluation of ovarian function in endometriosis.

Geriatric gynaecology

The menopause is the physiologic cessation of normal, cyclic ovarian function. The development of vasomotor symptoms, atrophic changes in the genito-urinary system and osteoporosis are associated with oestrogen deficiency. Osteoporosis is the most important consequence of ovarian failure because it causes considerable morbidity and mortality. There is no simple screening test for detecting postmenopausal women who are at risk of developing osteoporosis. Oestrogen replacement therapy affects lipid metabolism and may be associated with the risk of developing endometrial cancer, breast cancer and thromboembolic disease. The addition of a progestogen regime have shown to reduce the risk of endometrial pathology. The most consistent and beneficial effect of oestrogen is the prevention of osteoporosis and subsequent fractures. Non-hormonal treatment regimes for postmenopausal osteoporosis include calcium, calcitonin and 1-alpha hydroxyvitamin D. It may be possible to use hormonal treatment for the optimal control of menopausal symptoms and non-hormonal treatment as long term prophylaxis.

Effect of a beta-adrenoceptor antagonist, pindolol, on human uterine smooth muscle

The effect of a beta-adrenoceptor antagonist, pindolol, on uterine smooth muscle in term pregnant women was studied in vitro and in vivo (in hypertensive women). In most preparations in vitro and in most patients in vivo, the drug induced an inhibitory effect on spontaneous uterine activity. The fetal heart rate was not affected by the drug. These actions of pindolol would make it an appropriate drug in the therapy of hypertension in pregnancy.

Oxytocinase activity in human amniotic fluid and its relationship to gestational age

Oxytocinase (EC 3.4.11.3) activity in amniotic fluid samples obtained from 200 normal pregnant women (mean age, 28 years) between 14 and 40 weeks of gestation and during active labor was assayed using S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN) separately as substrates. With both substrates, amniotic fluid oxytocinase activity correlated inversely with gestational age; the level of the enzyme, which was highest in early pregnancy, decreased exponentially to a minimum near term and during labor. However, whether oxytocinase activity in the amniotic fluid is of any significance for the maintenance and/or termination of pregnancy remains to be established.

Elevated intravesicular fluid thyroid-stimulating hormone concentration in hydatidiform mole

In an attempt to explain hyperthyroidism in hydatidiform mole, concentrations of immunoreactive thyroid-stimulating hormone (TSH) together with human-chorionic gonadotrophin (beta-hCG) were measured in the serous fluid obtained from 43 patients aged 15-45 years and with amenorrhea 11-31 weeks. Elevated concentrations of these two hormones were found in all samples. It is probable that hyperthyroidism could stem from TSH immunologically similar to pituitary TSH and distinct from hCG and luteinizing hormone (LH) that we have identified in hydatid vesicles.

Is vasoactive intestinal polypeptide the principal transmitter involved in human penile erection?

Previous work from this laboratory reported on the effects of several autacoids and other agents on strips of human corpus cavernosum (cc) muscle. These investigations indicated the presence in the cc muscle of a) atropine-sensitive cholinoceptors, b) alpha- and beta-adrenoceptors and c) a non-adrenergic non-cholinergic mechanism. Several recent publications have presented evidence in support of the possibility that vasoactive intestinal polypeptide (VIP) is an important, or the chief, transmitter in human penile erection. This paper describes the actions of VIP and other compounds on the cc muscle and the effect of intracavernous injection of VIP in volunteers. Among the agents tested, VIP was the most potent relaxant of the cc muscle. This effect, which was seen at a dose as low as 0.03 nM, was suppressed by VIP antiserum. The response of the isolated penile vasculature to VIP was similar. VIP antiserum had no effect on the relaxation of the cc muscle produced by field stimulation. In five of the seven subjects given intracavernous VIP (1.0 micrograms.) some degree of penile enlargement was evident, but none had an erection. It is suggested that local release of VIP, withdrawal of the alpha-adrenoceptor mediated tonic supply to the penis and the activation of the latter's beta-adrenoceptors are all probably involved in penile erection in man.

Steroidogenic expression of delta 5-3 beta-hydroxy pathway of androgen biosynthesis by human breast carcinoma

In order to determine whether human mammary tumours could contribute to cholesterol and dehydroepiandrosterone biosynthesis in breast cancer patients, incubations of homogenates of infiltrating ductal carcinoma were carried out separately with 2-14C acetate (patient, n = 6; 21-80 years) and 7n-3H pregnenolone (patient, n = 5, 36-74 years) as substrates. With the aid of the reverse-isotope dilution technique, 14C cholesterol and 3H dehydroepiandrosterone were characterized; these two gave maximum yields of 2.38 X 10(-4)% and 9.42 X 10(-2)% respectively. These results indicate that there exists a potential for the synthesis of cholesterol and dehydroepiandrosterone in vivo. It is suggested that the biosynthetic pathway involved in the synthesis of the latter is; acetyl CoA----cholesterol----pregnenolone----17 alpha-hydroxypregnenolone----dehydroepiandrosterone.

Intrauterine responses to nipple stimulation in late pregnancy

Characteristics of intrauterine activity in response to nipple stimulation were studied in 9 healthy pregnant subjects at term. All patients showed an increase in uterine activity varying from 10 to 730%. In 1 subject, marked uterine hypertonus was noted which resulted in profound fetal bradycardia. This response was transient, lasting 5.5 min, and fetal outcome unaffected. We believe that nipple stimulation is associated with a higher incidence of increased uterine activity in terms of frequency, intensity and basal tone, than has been previously recognized. This uterine hypertonus may affect the fetal heart rate adversely indicating the need to exercise caution when adopting this manoeuvre in late pregnancy, particularly when there is already evidence of fetal compromise.

Prostaglandins, not cyclic GMP, inhibit oxytocinase isoenzymes from human amniotic fluid in vitro

Two isoenzymes of oxytocinase (EC 3.4.11.3) activity were fractionated from human amniotic fluid samples between the 14th and 22nd weeks of gestation by Ultrogel acrylamide-agarose gel filtration and partially characterized. The isoenzymes were competitively inhibited by PGE1, PGE2 and PGF2 alpha more at pH 6.2 than at pH 6.8, whereas cyclic GMP (cGMP) and its 8-bromo derivative had no effect at either pH. The implications of these findings are discussed and it is suggested that since the activity of amniotic fluid oxytocinases is very low or minimal at or near term, inhibition of these by prostaglandins may not have physiological significance in the initiation of human parturition.

Complications of beta-mimetic therapy in preterm labour

Selective beta-mimetic drugs are the most frequently used agents for arresting preterm labour. For this purpose these drugs have to be given in high doses for several hours and since they act on several organ systems, side-effects, some of which are potentially dangerous, appear. These hazards, which involve chiefly the cardiovascular and metabolic areas, have been examined in the light of available experience with these drugs. This review considers the possible mechanisms for the side-effects and offers suggestions on how the dangers in the use of beta-mimetic drugs in preterm labour might be avoided.

Multimolecular forms of oxytocinase activity in the human uterus and their inhibition by prostaglandins and cyclic GMP

Oxytocinase (EC 3.4.11.3) activity was measured in uterine homogenates from pregnant and non-pregnant women using S-benzyl-L-cysteine-p-nitroanilide (BCN) and L-leucine-p-nitroanilide (LN) separately as substrates. There was no significant difference between the specific activity of the enzyme in the pregnant and non-pregnant uterus. The uterine homogenates were also subjected to gel filtration on Ultrogel AcA 22 column and two hydrolyzing activity peaks from the pregnant uterus (PUI, PUII) and three from the non-pregnant uterus (UI, UII, UIII) were obtained. Although the pattern of hydrolysis of the two substrates by the enzyme peaks was similar, the hydrolysis of LN was greater than that of BCN. PUII, UII and UIII showed higher affinity for the substrates than PUI and UI, and the affinity of all isoenzymes was significantly greater for LN than BCN. These uterine oxytocinases appeared to be metallo-aminopeptidases and were potently inhibited by Cu2+, Zn2+ and prostaglandins (PGs). Cyclic GMP (cGMP) and its 8-bromo derivative, however, inhibited only PUI and UI. The divalent cations and PGs were equipotent against the hydrolysis of both substrates, but cGMPs were more effective against BCN hydrolysis. All of these inhibitions depended on the pH of the incubation medium and types of the inhibition by PGs and cGMPs were mixed and uncompetitive respectively. The implications of these findings in relation to human parturition have been discussed.

Another look at initiation of human parturition

Despite our moderate understanding of the physiology of the initiation of labour in various animal species, notably ruminants and rodents, the mechanism in man remains enigmatic. In the initiation process in the human the major role is apparently taken by the placental and fetal membranes, while the fetus may modulate the timing of labour. This review sets out to examine current knowledge of the process of initiating and maintaining parturition in the human.

Inappropriate luteinizing hormone concentration in human breast cancer

As part of a programme to assess the para-endocrine behaviour of human infiltrating ductal breast carcinoma among Chinese women, this study was designed to compare (Mann-Whitney U test) the immunoreactive mammary tumour tissue concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), human chorionic gonadotrophin (beta-hCG) and prolaction (PRL) at stages I (n = 9), II (n = 12) and III (n = 7) with that of normal breast tissue (n = 8). It was found that with the exception of FSH and beta-hCG in stages I and III significantly elevated concentrations of protein hormones were noted at all stages of malignancy. The possible importance of these findings in multi-stage mammary carcinogenesis is discussed. It is suggested that measurement of LH concentration may provide an endocrine basis to facilitate the diagnosis of tumours to serve as a guide to the biological behaviour of mammary neoplasms.

Plasma levels of 13,14-dihydro-15-keto PGE2 after vaginal application of a new PGE2 film

To determine the release and absorption profile of prostaglandin E2 from a new vaginal film formulation containing 850 micrograms PGE2, serial plasma levels of 13,14-dihydro-15-keto PGE2 were measured by radioimmunoassay in pregnant women between 16 and 18 weeks gestation. A control group, using placebo vaginal film was included in the study. There was a somewhat uniform increase in the plasma levels of the PGE2 metabolite, reaching peak levels between 4 and 6 hours after application of the film. The findings suggest that this drug formulation could be used clinically when slow constant release of the prostaglandin is required over a period of hours such as in pre-induction cervical ripening of term pregnancy.

Anencephaly: a retrospective analysis in Singapore. 1976 to 1980

Records of 93 cases of anencephaly from three maternity hospitals in Singapore between 1976 and 1980 were analysed. The incidence was 0.54 per 1000 births. No significant correlation between anencephaly and local seasonal conditions could be found for Singapore.

Cholesterol synthesizing enzymes in term human fetal amnion

Based on the observations that human fetal membranes possess the ability to synthesize steroid hormones, we sought to investigate the precursor role of 2 - 14C acetate in cholesterol formation by term human fetal amnion. Concentrations of derivatized 14C cholesterol was measured by reverse-isotope dilution technique in incubations of 2 - 14C acetate with homogenates of term fetal amnion dissected from 5 human placentae (37-40 weeks gestation) delivered vaginally from uncomplicated pregnancies (age 22-29 years). Controls consisted of homogenates heated in a boiling water bath for 10 min. The data presented demonstrate incorporation of 2-14C acetate into 14C cholesterol by the viable tissue. The extent of enzymic conversion varied from 0.002% to 0.076%. The small but definite conversion indicates that the homogenates of term human fetal amnion contain the full complement of enzymes necessary to catalyse the transformation of acetate to cholesterol. The metabolic need for cholesterol supply during labor is discussed.

Altered hypothalamic-pituitary-testicular function in incomplete testicular feminization syndrome

An 18-year-old 46 XY patient with the syndrome of incomplete testicular feminization was investigated. The clinical phenotypic features were distinctive and typical of the 4 46 XY cases previously reported. The findings of elevated plasma T4 with evidence of incomplete development of female secondary sex characteristics suggest partial end organ insensitivity to the androgen at the target tissues. This possibility is substantiated by the high plasma LH level, presumably the consequence of the relative inability of the hypothalamic-pituitary unit to respond to testosterone in the feedback regulation of LH secretion. It is therefore suggested that, compared to normal males, the patient had an altered hypothalamic-pituitary-testicular function.

Thromboxane A2 and prostacyclin levels in molar pregnancy

Plasma levels of thromboxane (TX) A2 and prostacyclin (PGI2), as measured by radioimmunoassay of their respective stable metabolites TXB2 and 6-keto PGF1 alpha, were studied in six molar pregnancies immediately before, immediately following and 24 h after evacuation of the uterus. The mean (SD) levels for TXB2 were 150 (41), 137 (32) and 125 (25) pg/ml respectively, and for 6-keto PGF1 alpha the respective values were 225 (52), 226 (127) and 213 (49) pg/ml. There was no significant difference in the levels of prostanoids between the samples taken at the various time intervals. The concentration of these prostanoids in molar intravesicular fluid was also determined. Their respective mean (SD) pg/ml values were 3682 (760) for TXB2 and 2969 (744) for 6-keto PGF1 alpha. In 15 normal pregnancies of equivalent gestation, the mean amniotic fluid levels of TXB2 and 6-keto PGF1 alpha were 34 (17) and 146 (86) pg/ml respectively. The ability of molar trophoblast to generate the prostanoids from [14C]arachidonic acid in vitro was also demonstrated. Mean (SD) values for TXB2 and 6-keto PGF1 alpha were 12.2 (2.6) and 13.2 (1.8) pg/mg protein/min, respectively. It is likely that the high concentrations of prostanoids in vesicular fluid reflect the synthesizing ability of the villus vesicles. The mole contributes little to the circulatory prostanoids possibly because its villi are deficient in blood circulation.

Epidemiologic analysis of fetal death in utero in Singapore

Records on 1777 cases of missed abortion and 1001 cases of intrauterine fetal death in three major maternity hospitals in Singapore between 1976 and 1980 were analyzed. The overall incidence of these two conditions was 10.35 and 5.82 per 1000 births, respectively. During the 5-year period, the incidence of missed abortion increased consistently, from 8.05 to 12.76 per 1000 births. In contrast, during the same period, the incidence of intrauterine fetal death declined steadily from 6.44 to 4.68 per 1000 births. Missed abortions occurred more frequently in the early part of the year, especially in the months of March, April and May. The incidence of missed abortion and its correlation with possible environmental factors are discussed.

Maternal plasma estradiol and progesterone levels during therapeutic abortion induced by 16, 16 dimethyl PGE2 p-benzaldehyde semicarbazone ester

Estradiol and progesterone levels in maternal plasma after administration of 16, 16-dimethyl-PGE2 p-benzaldehyde semicarbazone ester (16,16-PGE2) 6 hourly for abortion were studied in 27 women in the second trimester of pregnancy and in 49 patients with fetal death in utero. Basal maternal plasma levels of estradiol and progesterone measured before prostaglandin injection were significantly lower in cases of fetal death in utero than in the other subjects. After 16,16-PGE2 injection, plasma levels of estradiol and progesterone fell more rapidly and to a greater extent in cases of fetal death in utero than those with normal pregnancy at corresponding gestations; the decline of plasma estradiol levels was quicker and more marked than that of progesterone. Thus, 16,16-PGE2 appears to exert a differential effect on estradiol and progesterone biosynthesis.

A comparison of some pharmacological actions of prostaglandin E1, 6-oxo-PGE1 and PGI2

Some pharmacological actions of prostaglandin E1 (PGE1), 6-oxo-PGE1 and PGI2 have been studied. 6-oxo-PGE1 and PGE1 relaxed guinea-pig tracheal muscle in vitro and increased nasal patency in normal volunteers and in subjects with vasomotor rhinitis whereas PGI2 produced opposite effects. All three compounds produced bronchodilatation in the anaesthetised guinea-pig and relaxed human respiratory tract muscle in vitro. PGI2 was several times more potent than either 6-oxo-PGE1 or PGE1 against ADP-induced aggregation of human and baboon platelets in vitro. Intravenous 6-oxo-PGE1 in the baboon caused an ex vivo inhibition of platelet aggregation, but the EC50 was 7.7 times that of PGI2. As a vasodepressor in the baboon 6-oxo-PGE1 and PGI2 were equipotent. Thus with the exception of the vasodepressor effect, the actions of 6-oxo-PGE1 qualitatively and quantitatively resembled those of the structurally related PGE1 rather than those of PGI2.

Selective inhibition of multimolecular forms of human serum and placental oxytocinase activity by prostaglandins and cyclic GMP

Ultrogel acrylamide-agarose chromatography was employed for fractionation of oxytocinase isoenzymes from serum of pregnant women and from human placenta. Using S-benzyl-L-cysteine-p-nitroanilide ( BCN ) and L-leucine-p-nitroanilide (LN) as substrates, three activity peaks (PI, PII, PIII) from placenta, and one peak (SI) from serum were identified. SI coincided with PII, and with all isoenzymes the hydrolysis of LN was greater than that of BCN . Prostaglandins E1, E2 and F2 alpha inhibited all oxytocinases , more potently the hydrolysis of LN than BCN and at pH 6.2 than at pH 6.8. Although cyclic GMP and its 8-bromo derivative similarly inhibited these isoenzymes except PIII, they were considerably more effective against the hydrolysis of BCN than LN.

Inhibition of platelet aggregation and antagonism of vasopressin-induced ECG changes in primates by a carboprostacyclin analogue, ZK 36374

A chemically stable carboprostacyclin analogue, ZK 36374 has been compared with two other prostacyclin derivatives with respect to ADP-induced in vitro aggregation of baboon and human platelets and ex vivo platelet aggregation in the baboon. ZK 36374 was also tested on the systemic arterial blood pressure of the baboon and against vasopressin-induced ECG changes in primates. Compared to the other two compounds, ZK 36374 displayed enhanced anti-platelet aggregating activity; there was dissociation between this property and its hypotensive potency. ZK 36374 antagonized the vasopressin-induced ECG changes. These results indicate that ZK 36374 possesses therapeutic potential in vascular disease including that affecting the coronary vessels.

Cholinoreceptors in the corpus cavernosum muscle of the human penis

Acetylcholine produced contraction, relaxation or a biphasic effect on corpus cavernosum muscle strips of human penis. These effects were antagonized by atropine but were modified by hexamethonium or tetrodotoxin suggesting the presence of excitatory and inhibitory muscarinic receptors in the human penis. Nicotine and DMPP also produced contraction or relaxation of the corpus cavernosum muscle strips. These effects were presumably indirect as they were abolished by hexamethonium and tetrodotoxin. Contractions produced by nicotine or DMPP were abolished by atropine whereas the relaxations produced by these agents were only partially blocked by atropine. Hence, the receptors mediating these relaxations are unlikely to be entirely muscarinic.

Inhibition of platelet aggregation and reversal of vasopressin-induced ECG changes by a carboprostacyclin analogue, ONO 41483, in primates

15-cyclopentyl-omega-pentanor-5(E)-carbacyclin (ONO 41483), a chemically stable carboprostacyclin analogue, was 3.3 times less active than prostacyclin but was 2.6 times more active than carboprostacyclin in inhibiting aggregation of ADP-induced baboon platelet in vitro. On human platelets in vitro, ONO 41483 was 9.4 times less active than prostacyclin and 12.7 times more active than carboprostacyclin. ONO 41483 was 3.7 times less active than prostacyclin but was 2.2 times more active than carboprostacyclin in producing a fall in arterial blood pressure in anaesthetised baboons. Intravenous and oral administration of ONO 41483 in baboons produced ex vivo inhibition of ADP-induced platelet aggregation at doses that did not affect blood pressure or heart rate. In addition, bolus intravenous doses (3 to 10 micrograms/kg) of ONO 41483 reversed vasopressin-induced ECG changes in the monkey, suggesting an ability of the compound to relieve coronary spasm.

Reversal of vasopressin-induced coronary vasoconstriction by a PGE1 analogue (ONO 1206) in primates

17 (S)methyl-omega-homo trans delta 2 PGE1 (ONO 1206) an analogue of PGE1 was studied on vasopressin-induced ECG changes in four male monkeys and three female baboons. Bolus intravenous doses of vasopressin (0.8 I.U. to 1.0 I.U./kg) produced flattening of the T wave (2 monkeys) elevation of ST segment (1 baboon and 1 monkey) and inversion of T wave (1 baboon). Inverted T waves were also present in one baboon and one monkey prior to any drug administration. In four out of seven animals, boLus intravenous doses (5 to 15 micrograms/kg) of ONO 1206 reversed the ECG changes produced by vasopressin and in one animal ONO 1206 reversed the existing inverted T wave. These findings indicate that vasopressin is a suitable agent for the induction of coronary vasoconstriction in primates and that ONO 1206 is able to reverse this effect.

Adverse reactions to isoniazid on ingestion of fish with a high histamine content

On eating preparations of a particular variety of fish, the skipjack (bonito), patients with tuberculosis on isoniazid repeatedly developed symptoms very similar to those of histamine poisoning. Skipjack was found to contain probably the highest concentration of histamine reported in fish. Isoniazid is a potent inhibitor of histaminase which normally plays an important role in the metabolism of histamine in the body. It is suggested that the symptoms seen in these patients were, in fact, due to histamine. In these circumstances the high histamine content of skipjack and the interference by isoniazid with the metabolism of the amine presumably play complementary roles in the production of histamine poisoning; each of these factors by itself is apparently inadequate to produce such intoxication. An analysis of the symptoms manifested by 21 patients is presented.

An analysis of possible nervous mechanisms involved in the peristaltic reflex

1. The effects of drugs on peristalsis and on the contractions of the two muscle coats of the isolated guinea-pig ileum in response to co-axial electrical stimulation have been studied.2. Co-axial stimulation (0.1 msec pulses) never produces simultaneous contraction of both muscle coats. When one muscle contracts, the other either relaxes or remains quiescent.3. The circular muscle contraction has two components. The first is reflex in origin and is brought about either by distension of the gut with increasing intraluminal filling or by the contraction of the longitudinal muscle in response to electrical stimulation at low frequency (1/sec), provided this raises the intraluminal pressure to the threshold for eliciting the circular muscle contraction. As the circular muscle contracts, the longitudinal muscle relaxes although stimulation continues. If the circular muscle contraction is prevented by reducing the intraluminal filling, or by adding a ganglion-blocking drug, the longitudinal muscle remains contracted until withdrawal of the stimulus.4. In the presence of hyoscine, the reflex contraction of the circular muscle is unimpaired but, since the longitudinal muscle contraction is abolished, a higher intraluminal pressure is required to elicit the reflex.5. The second component of the circular muscle contraction appears in response to electrical stimulation at high frequency (3-10/sec), upon withdrawal of electrical stimulation. This delay indicates the simultaneous stimulation of a dominant inhibitory innervation.6. The excitatory nerves to the circular muscle require a higher frequency of stimulation than those to the longitudinal muscle, which respond to single shocks.7. Cholinergic blocking agents (hyoscine, morphine, hemicholinium and botulinum toxin) antagonize the responses of the longitudinal muscle to co-axial stimulation without affecting those of the circular muscle, thus suggesting that the excitatory fibres to the circular muscle are not cholinergic. Prostaglandins (E(1) and E(2)) selectively antagonize the circular muscle contractions evoked by co-axial stimulation. Tetrodotoxin blocks both longitudinal and circular muscle responses.8. Dimethylphenylpiperazinium (DMPP) and 5-hydroxytryptamine (5-HT) stimulate ganglia but have no direct action on the smooth muscle of guinea-pig ileum.9. During a maintained contraction of the longitudinal muscle in the presence of high concentrations of acetylcholine (2.5 x 10(-7) to 10(-6) g/ml.) a contraction of the circular muscle accompanied by a relaxation of the longitudinal muscle is elicited by distension of the gut, and by co-axial stimulation. Similar reciprocal responses are produced by 5-HT or by DMPP and they are finally blocked by DMPP.10. These results are consistent with the hypothesis that in the myenteric plexus there exists an arrangement of nerves which ensures that the two muscle coats of the intestine do not contract simultaneously but are activated reciprocally so that when one muscle layer contracts the other relaxes or is prevented from contracting.