Enhancement of bradykinin-induced prostacyclin synthesis in porcine aortic endothelial cells by pertussis toxin Possible implication of lipocortin I

Bradykinin-stimulated prostacyclin synthesis in porcine aortic endothelial cells was enhanced by pretreatment of the cells with pertussis toxin or islet-activating protein (IAP) for 5 hr or longer. Although ADP-ribosylation of a protein with a molecular weight of 41–42 kD in the cell membranes was completed by 3 hr after the addition of IAP into the incubation medium, there was good correlation between enhancement of bradykinin-induced prostacyclin synthesis and ADP-ribosylation of the IAP substrate over a wide range of IAP concentrations. Furthermore, even if IAP was removed from the incubation medium at 3 hr, bradykinin-induced prostaglandin synthesis at 24 hr was still potentiated. Cycloheximide and actinomycin D enhanced bradykinin-induced prostacyclin synthesis and apparently blocked the effect of IAP. Since this result suggested the involvement of an inhibitor protein(s) of prostacyclin synthesis in the IAP effect, we studied the effect of IAP on the level of lipocortin I which is known to inhibit phospholipase A₂. Western and Northern blot analyses revealed that IAP decreased the amounts of protein and mRNA of lipocortin I. These results suggest that the enhancement of bradykinin-induced prostacyclin synthesis by IAP is associated with a decrease in the level of lipocortin I.     

Ontogeny of the pituitary-thyroid system in fetal rats: Observations on the fetal thyroid after maternal treatment with goitrogen

The critical time of onset of the reciprocal relationship between the pituitary and the thyroid in fetal rats was assessed by the appearance of goiters in fetuses after maternal treatment with goitrogen, propylthiouracil (PTU), on various days of gestation. The assessment was based on changes in the weight and histology of the fetal thyroids. The day following overnight mating was regarded as day 1 of gestation. Pregnant rats were treated with 40 mg PTU each day for two days and autopsied on the third day. The various experimental periods were days 16–18, 17–19, 18–20, 19–21, and 20–22. PTU given to pregnant rats on days 16 and 17 did not cause any change in the fetal thyroids. PTU given on days 17 and 18 caused only a slight increase of fetal “thyroid weight/body weight” ratio. In all other experimental periods (days 18–20, 19–21, and 20–22), PTU induced conspicuous goiters in fetuses, which was reflected by an increased weight of thyroids, an increased height of follicular cells, and a decreased amount of colloid stored in follicles. The results suggest that in fetal rats, the reciprocal relationship between the pituitary and the thyroid is established on approximately days 19–20 of gestation.     

Teratogenic Characteristics by Single Dosing of Antineoplastic Platinum Complexes in Rats

We investigated the embryolethality and teratogenicity of a new platinum complex, 254-S, and cisplatin (CDDP) by single dosing to dams on one day during the period of organogenesis. The results are summarized as follows: (1) Embryolethality was maximal after 254-S treatment on day 7 of gestation (Day 7) and after CDDP treatment on Days 6 to 9. It decreased with advancing gestational age. (2) Both 254-S and CDDP were teratogenic. The critical period for induction of malformation appeared twice for 254-S, at Days 6 to 9 and at Days 14 to 15, and once for CDDP, at Days 5 to 8. (3) The types of malformations induced by 254-S or CDDP were different, indicating different mode of teratogenesis. 254-S caused malformations mainly in the craniofacial or limb bud areas in the biphasic manner, whereas CDDP caused malformations mainly of the limb buds in the monophasic manner. (4) Malformations of the limb/digit and tail that are known to have critical periods during the late stage of organogenesis were induced by treatment with 254-S on Day 7 and with CDDP on Day 5 or 6.     

Ontogeny of thyrotrophin concentration in perinatal rats

Negative feedback control by triiodothyronine (T3) of thyrotrophin (TSH) secretion from rat pituitary glands was studied during the perinatal period of rat development. Foetal serum TSH concentration declined significantly between 20 and 21 days of gestation, reached a low level at delivery, and remained low for several days after birth. T3 suppressed serum TSH concentration in a dose-responsive manner when given to foetuses on day 20 of gestation at 0.13 to 2.0 micrograms/100 g body weight of the estimated body weight. The responses of serum TSH levels and thyroid weights to PTU treatments differed with gestational age. We conclude that negative feedback control by T3 of serum TSH concentration exists in rat foetuses as early as day 20 of gestation and differs from that found in adult rats.     

A change in the adrenocortical response in perinatal rat offspring given betamethasone 17,21-dipropionate

The potent synthetic glucocorticoid betamethasone 17,21-dipropionate (BMDP) produces adrenal hypertrophy in the rat foetus at late pregnancy by mediation of the hypothalamo-pituitary system, but causes adrenal atrophy, and acts as a normal glucocorticoid, in the adult rat. The change of the adrenal cortical response to the BMDP treatment was investigated in perinatal rat offspring. The pituitary ACTH potency was also determined in rat foetus treated with BMDP. The time course of the adrenal corticosterone level after the BMDP treatment was similar to that of the plasma level on day 19 to 21 in the rat foetus from the adrenalectomized mother, both decreased at 2 h, but rose gradually at 4 h to 6 h, exceeding the control level at 24 h and 48 h after the BMDP treatment. The pituitary ACTH potency in the foetus decreased at 24 h and 48 h after the BMDP treatment, suggesting that ACTH released from the foetal pituitary stimulated adrenal corticoidogenesis. Maternal adrenalectomy did not essentially alter this stimulating activity of BMDP, which appeared in the perinatal rat offspring, only when BMDP was administered during the foetal period. These findings suggest that the hypothalamo-pituitary adrenocortical response to the treatment with BMDP drastically changes at the early neonatal age.     

Predicting recovery of ambulatory function after hypertensive putaminal hemorrhage by multivariate analysis of acute-phase clinical data

In 66 patients with hypertensive putaminal hemorrhage, several acute-phase clinical parameters were subjected to multivariate analysis and the usefulness of such analysis in predicting the eventual recovery of ambulatory function was evaluated. Seven items were studied: age, laterality of the lesion, computed tomography classification, hematoma volume, level of consciousness on admission, severity of motor impairment of the affected leg on admission, and the treatment employed. A numerical prediction of ambulatory function was derived from an equation in which each item was scored and weighted. This value was compared with that of the actual ambulatory ability several months after onset, as rated on a 5-point scale. In these 66 cases, the predicted and actual outcomes were well correlated (r = 0.871). The results indicate that an accurate prognosis can be made on the basis of clinical data obtained in the acute phase of putaminal hemorrhage.     

LY315920NA/S-5920, a selective inhibitor of group IIA secretory phospholipase A2, fails to improve clinical outcome for patients with severe sepsis

OBJECTIVE: Group IIA secretory phospholipase A2 (sPLA2-IIA), released during inflammation, is increased in severe sepsis, and plasma levels are inversely related to survival. In a previous study, a selective inhibitor of sPLA2-IIA (LY315920NA/S-5920) was well tolerated and appeared to improve survival in a subgroup of patients who received the drug within 24 hrs of first sepsis-induced organ failure. This study was designed to determine whether improvement in survival could be confirmed in a larger patient population meeting the characteristics of that subgroup. DESIGN: Multicenter, double-blind, placebo-controlled, parallel-group clinical trial of LY315920NA/S-5920 in patients with severe sepsis. SETTING: Seventy-five institutions worldwide. PATIENTS: A total of 373 patients with at least two sepsis-induced organ failures. INTERVENTIONS: Patients were randomized 1:1 to receive LY315920NA/S-5920 (target plasma concentration of 800 ng/mL; n = 188) or placebo (n = 185). Study medication was administered as a continuous intravenous infusion for 168 hrs. MEASUREMENTS AND MAIN RESULTS: The study was terminated after data on 250 patients suggested a significant improvement in 28-day all-cause mortality would not be found if the trial continued as planned. The mortality rate was 39.4% in the LY315920NA/S-5920 group, compared with 31.9% in the placebo group (p = .092). The negative trend in mortality was most pronounced among patients with cardiovascular failure at baseline (41.6% vs. 28.7%; p = .008) and patients whose culture data at baseline were negative (42.9% vs. 22.7%; p = .045). The negative trend in mortality is not explained by adverse events, microbiology, or laboratory data. CONCLUSIONS: Continuous 7-day infusion of an inhibitor of sPLA2-IIA had no beneficial effect on 28-day all-cause mortality among severe sepsis patients with at least two organ failures. This study did not confirm earlier promising subgroup results with LY315920NA/S-5920, which provides a reminder that subgroup effects should be viewed cautiously, especially when primary effects are not significant.     

Cytochrome P-450-dependent monooxygenase activities in prenatal and postnatal human livers: comparison of human liver 7-alkoxycoumarin O-dealkylases with rat liver enzymes

Human liver samples from 17 embryos, 5 fetuses, 5 infants and 4 adults were used to investigate human liver cytochrome P-450-dependent 7-alkoxycoumarin O-dealkylase activities, and their drug-metabolizing activities were compared to those of rat livers. The O-dealkylase activities in human embryos and fetuses were very low, although detectable, similar to those in fetal rats. Both male and female rats showed a postnatal increase of hepatic O-dealkylase activities with a maximum at about 30-40 days after birth and then a decline in the activities which was marked in female rats. Adult female rats showed a marked decrease in the hepatic enzyme activity observed in the O-depropylation reaction rather than the O-demethylation and O-deethylation reactions. During the developmental period of human infants, the O-demethylase activity, but not O-depropylase activity, increased gradually. Enzymes in adult human livers metabolize the O-methyl derivative of 7-hydroxycoumarin in preference to the O-ethyl and O-propyl derivatives. The metabolic activities of human adult enzymes for 7-alkoxycoumarin resembled those in adult female rats and were quite different from those in male rats. The study demonstrated that caution must be exercised in extrapolating pharmacological results from animal to man in the field of drug metabolism.