Evidence that physiologic levels of circulating estrogens and neonatal sex-imprinting modify postpubertal hepatic microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase activity

Intact, but sham-operated female rats had 2- to 3-fold higher levels of hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity than their male counterparts (15--21.5 vs. 6.7--8.7 nmol mevalonate/mg protein per h). The activity of the hepatic enzyme declined to about the same relative degree (40--60%) in male and female rats that were gonadectomized after puberty (53 days of age) and killed 5 weeks later. Implantation of silastic capsules containing 17 beta-estradiol increased the level of hepatic 3-hydroxy-3-methylglutaryl CoA reductase to levels found in sham-operated controls. In rats that were gonadectomized in infancy (12 h old) and killed 7--8 weeks later, the level of enzyme activity was not altered in females, but it was increased from 60--240% in males. Consequently, following neonatal gonadectomy, male-female differences in enzyme activity were no longer apparent. Implantation of silastic capsules containing estradiol in neonatally gonadectomized rats resulted in a doubling of enzyme activity in both males and females. Ovariectomy reduced plasma estrogen levels, but implantation of estradiol in gonadectomized males and females increased the hormone level to that found in sham-operated females. Thus, the results strongly suggest a role for physiologic levels of estrogen as a positive effector of 3-hydroxy-3-methylglutaryl CoA reductase activity. Neonatal sex imprinting also appears to modulate the enzyme activity since sex-mediated differences are effaced by gonadectomy in infancy, but not by gonadectomy following puberty.     

Determination of dimethyl sulfoxide in serum and other body fluids by gas chromatography

A gas chromatographic procedure for the determination of dimethyl sulfoxide in serum, plasma, urine, and CSF is described. Features of the method include simple sample preparation, excellent accuracy, linearity, and precision. Results obtained on patient samples following intravenous administration are presented.     

Effects of mianserin, a new antidepressant, on the in vitro and in vivo uptake of monoamines

1 The effects of mianserin and of selected tricyclic antidepressants were compared in a number of monoamine uptake models. 2 The ability of mianserin to block the noradrenergic neurone membrane amine pump of rabbit brain stem slices was comparable to that of imipramine and amitriptyline and less than that of desipramine and nortriptyline. Both mianserin and desipramine were competitive inhibitors of noradrenaline uptake in vitro. The effect of mianserin on noradrenaline uptake in vivo was studied both peripherally and centrally. The ability of 6-hydroxydopamine to lower rat heart noradrenaline levels was found to be very sensitive to inhibition by tricyclic antidepressants. Mianserin was active in this model. However, its ability to block the 6-hydroxydopamine-induced fall in rat heart noradrenaline concentration was appreciably less than that of the tricyclics studied. 3 Mianserin, like tricyclic antidepressants, was essentially devoid of effect on dopamine uptake both in vitro and in vivo. 4 The ability of mianserin to inhibit [3H]-5-hydroxytryptamine uptake by rat hypothalamic synaptosomes was appreciably less than that of the tricyclic antidepressants studied. Mianserin was essentially devoid of effect on rat brain 5-hydroxytryptamine uptake in vivo. 5 It is concluded that in certain situations large doses of mianserin may block noradrenaline uptake in vivo. However, in no way does mianserin rival tricyclic antidepressants in blocking monoamine uptake in vivo. The clinical efficacy of mianserin cannot be attributed to inhibition of monoamine uptake.     

Incidence and hospitalization patterns of insulin-dependent diabetes mellitus

Data from a statewide insulin-dependent diabetes mellitus (IDDM) registry in Rhode Island show that IDDM affects young adults (20-29 yr) as frequently as adolescents and teenagers (10-19 yr). Overall incidence less than 30 yr was 14/100,000 population. Peak incidence occurred at 10-14 yr (19/100,000 population). Poor diabetic control and infection accounted for 46-62% of hospitalizations among 275 known diabetic persons. Despite a 10-yr mean duration of diabetes, only 31% of hospitalized diabetic persons less than 30 yr of age reported ever having received outpatient diabetes education of two or more hours. Readmissions 1 yr after initial registration were more frequent for known (43%) than new-onset (18%) IDDM cases. Increased risk of readmission for both groups was associated with a poverty socioeconomic status. Total direct hospitalization costs for IDDM in persons under 30 yr of age in Rhode Island was $530,000 per year of $2,245 per patient.     

A vector model for magnetic hysteresis based on interacting dipoles

A model for magnetic hysteresis is described in which the applied field intensity is free to rotate as well as vary in magnitude. The model is an infinite lattice of ellipsoidal Stoner-Wolfarth particles withN^{3} = 8,27,64,125,216...independent and not necessarily identical particles per unit cell. Techniques for making this simple yet very general model computationally tractable are described. The model is intended primarily for studying the magnetic recording process in particulate storage media.     

Idiosyncratic cardiovascular response of human neonates to acoustic stimuli

The heart rate response of acoustic stimuli was assssed for 15 newborns between the ages of 24 and 48 hr. Results of the analyses of covariance demonstrated that although the subjects responded to the stimuli, their responses were idiosyncratic in magnitude, direction, and pattern of rate change. Although spectrum and duration of the stimuli were varied, they were found not to be significant sources of response variation.     

Platinosomes produced in cultured cells by platinum coordination complexes

Cells in culture were exposed to cis-dichlorodiammineplatinum (II) and platinum-uracil blue. No platinum could be demonstrated in an intracellular location morphologically or by electron-probe x-ray analysis in the case of the former compound. However, platinum was readily demonstrated in phagosomes or phagolysosomes after exposure of cells to platinum-uracil blue.     

An analysis of reproductive motivation in Shiraz, Iran

In a sample of 260 married men in Shiraz, the relationship of fertility to demographic, socioeconomic, and psychosocial (perceived economic value of children) variables is studied. The number of children ever born is closely associated with duration of marriage, but socioeconomic variables also exert a significant influence, especially the wife's educational level. Recent fertility is more closely associated with age of wife, but also with ownership of modern goods, which is also the major factor in current contraceptive use. The perceived value of children appears unimportant, negligible in recent fertility and contraceptive use and showing only a slight positive relationship between expected reliance on children for support in old age and the number of children ever born.     

Determinants of young children's search strategies in a large-scale environment.

26 3–6 yr olds searched for an object after traveling a route along which the object was used and later discovered missing (critical events). Ss then recalled the order of locations along the traveled route (sequence recall) and the locations for critical events (event recall); they also drew a map of the search environment. The correlation between event recall and search scores was significant only for Ss with good sequence recall. Correlations between sequence recall and search scores were higher for Ss who placed locations on the route in drawing maps. It is concluded that the acquisition of route knowledge in the development of spatial representation determined the likelihood that inferences would be made. When inferences were made, the accuracy of memories for sequences and events further determined the accuracy of the inferred critical search area. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)