Effect of L-tryptophan and restraint stress on hypothalmic and brain serotonin turnover, and pituitary TSH and prolactin release in rats.

The dose response and time course effects of L-tryptophan and restraint stress on the metabolism of serotonin and release of thyroid stimulating hormone (TSH) and prolactin (PRL) were tested in male rats. Both treatments increased serotonin turnover in the hypothalamus (H) and remaining brain tissue minus the cerebellum (brain) as determined by enhanced accumulation of serotonin following monoamine oxidase (MAO) inhibition. L-tryptophan but not restraint stress elevated levels of tryptophan in the cerebellum. Both L-tryptophan and restraint stress inhibited TSH release and stimulated PRL release. These findings indicate that enhanced rates of serotonin turnover produced by L-tryptophan and physical restraint are associated with inhibition of TSH and stimulation of PRL release from the anterior pituitary.     

The effects of varying concentrations of colchicine on the progression of grasshopper neuroblasts into metaphase

The effects of four concentrations of colchicine (2.5 x 10^-7, x 10^-5, x 10^-3, and x 10^-2 M) on the cell cycle of grasshopper neuroblasts have been determined by direct observations on living cells. The lowest concentration, 2.5 x 10^-7 M, does not completely disorganize the spindle but does retard its action. The three higher concentrations disorganize the spindle, so that all cells reaching metaphase are blocked in a c-mitotic condition throughout the period of observations (308 min at 38°C, the minimum duration of the cell cycle in untreated neuroblasts). Continuous treatment with all concentrations reduces the rate at which neuroblasts enter metaphase, the extent of the reduction being a function of increasing concentration and time of exposure. After a short exposure to 2.5 x 10^-5 M colchicine, the neuroblasts recover from the inhibiting effects on progression through the cycle to metaphase, but they show no recovery from the inhibiting effects on spindle formation for more than 3 hr. Apparent stimulation of progression rate occurs early in exposure to all concentrations and during recovery from a short exposure to 2.5 x 10^-5 M. Morphological alterations in the chromatin of telophase, interphase, and prophase cells are induced by the higher concentrations of colchicine. The data indicate that caution should be exercised in the use of colchicine for determining cell cycle duration and/or the effects of physical and chemical agents on the cycle.     

Effects of dopaminergic agonists and antagonists on cerebellar guanosine-3',5'-monophosphate (cGMP).

Apomorphine was found to cause an increase in cerebellar cGMP content. Bromocriptine, at a dose that caused stereotypies, neither elevated cGMP, nor blocked the apomorphine- induced rise in cGMP. The apomorphine-induced rise in cGMP was effectively blocked by haloperidol and some other neuroleptics, but not by sulpiride. These actions of the neuroleptics correlated with their ability to displace ³H-spiroperidol from striatal membranes, suggesting that dopamine receptor interactions were important in the cGMP changes noted. Based on the observation that haloperidol antagonized the increase induced by restraint, it is suggested that dopaminergic systems are involved in the reaction to stress.     

Isolation of an acyl-CoA carboxylase from the tapeworm spirometra mansonoides

An acyl-CoA carboxylase, which catalyzes the carboxylation of acetylpropionyl-, and butyryl-CoA, has been isolated from the tapeworm $\text{Spirometra}\text{mansonoides}$. The enzyme has an absolute requirement for ATP, Mg²⁺, and HCO₃${}^{\mathrm{?}}$ and, in addition, requires K⁺ for full catalytic activity. The enzyme has been purified 50-fold by a combination of calcium phosphate gel adsorption, ion-exchange column chromatography, and gel filtration. In its substrate specificity, K⁺ requirement, molecular size, and antigenic behavior, the tapeworm enzyme is similar to the acyl-CoA carboxylase of another helminth— the free-living nematode $\text{Turbatrix}\text{aceti}$.     

A multinational Andean genetic and health program. VIII. Lung function changes with migration between altitudes.

Studies of lung function in high altitude populations have suggested the influence of hypoxic environment on the development of this characteristic independent of confounding variables such as ethnicity and habitual exercise. However, often the effect of altitude on vital capacity is greater in children than adults, suggesting that more than developmental adaptation is operative. Also selective migration could account for the similarity of migrants and permanent residents at a destination altitude. To explore these problems we studied the lung function (FVC, FEV1, PFR) of 377 individuals who had migrated between altitudes in northern Chile. Migrant measurements were adjusted to those of permanent residents of appropriate age, sex and height at the altitudes of origin and destination. The measurements were then related to ethnicity (Spanish-Aymara ancestry), occupation and permanence, the latter combining information on both age at migration to and length of stay at a destination altitude. Upward migration was associated with increased chest depth, FVC and FEV1, but not height or other chest measurements. Downward migration had no significant effect. The flow-dependent test PFR was so sensitive to observer variability and occupation that it was difficult to establish its relationship to permanence. Unlike the body measurements, lung function measurements (especially PFR) tended to deviate from permanent controls at the origin altitude in a direction suggestive of selective migration, nor was permanence itself independent of ethnicity and occupation. Because of these difficulties the question of developmental adaptation in lung function may not be answerable in cross-sectional studies like the present and previous efforts, but rather in longitudinal investigations in which the control is the individual him/herself.     

A multivariate analysis of fatness and relative fat patterning.

Skinfold measurements (triceps, subscapular, suprailiac and medial calf) in four samples (376 boys, 352 girs, 338 men and 380 women from rural Colombia) were subjected to principal components analysis to identify components of obesity and relative fat patterning. Three components emerged which were similar in the four samples: a first component of fatness explaining 70-80% of the variance and two fat pattern components each explaining 10-15% of the variance: trunk-extremity and upper-lower body. Fatness and the trunk-extremity pattern components changed with age in children (7-12 years), but none of the components changed with age in adults (25-60+). The fatter tended to be more patterned in both age groups. Canonical correlation analysis revealed that socioeconomic status was more related to fatness than to patterning. With the exception of brothers, all first degree relatives (sib, parent-off-spring) and spouses were correlated in fatness. Some of the correlations between relatives--usually sibs, but not spouses--were also significant for the pattern components, suggesting a genetic basis for the known stability of this characteristic (Garn, '55a). Principal components analysis is a useful multivariate alternative for quantitative studies of anthropometric patterning.