Facial expressivity in dominant macaques is linked to group cohesion.

Social living affords primates (including humans) many benefits. Communication has been proposed to be the key mechanism used to bond social connections, which could explain why primates have evolved such expressive faces. We assessed whether the facial expressivity of the dominant male (quantified from the coding of anatomically based facial movement) was related to social network properties (based on social proximity and grooming) in nine groups of captive rhesus macaques (Macaca mulatta) housed in uniform physical and social environments. More facially expressive dominant male macaques were more socially connected and had more cohesive social groups. These findings show that inter-individual differences in facial expressivity are related to differential social outcomes at both an individual and group level. More expressive individuals occupy more beneficial social positions, which could help explain the selection for complex facial communication in primates.

Hydroxylation of phenylethylamine by rat liver preparations. Inhibition studies.

1. Rat liver 100,000 g pellet microsomal fraction p-hydroxylate phenylethylamine to tyramine in a relatively slow proceeding, NADPH-requiring reaction; Km 2.1 x 10(-5) M and Vmax 0.32 nmol/mg protein/20 min. 2. This reaction is inhibited, either competitively, noncompetitively or uncompetitively by a number of behaviorally active monomethylated and monohalogenated derivatives of phenylethylamine. 3. Whereas formation of tyramine was not significantly affected by L-phenylalanine or its p-chloro derivative, it was competitively inhibited by imipramine, iprindole and alprazolam. 4. It is suggested that at least some of the effects of these drugs may result from their ability to interfere with phenylethylamine metabolism.

Studies of the in vitro human plasma degradation of methionine-enkephalin.

1. Incubation of [3H]tyrosine methionine-enkephalin (6 x 10(-9) M final concentration) with human platelet-poor plasma (1:9 ratio to Trizma Base buffer, pH 7.4) results mostly (greater than 95%) in hydrolysis of the tyrosyl-glycine peptide bond. This enzymatic reaction is essentially completed within 90 min, showing a half-life, Km and Vmax of 12.8 +/- 2.5 min, 0.70 +/- 0.01 mM and 17.90 +/- 1.05 mumol/L/min, respectively. These values are comparable to those previously reported for the human plasma degradation of leucine-enkephalin. 2. As expected hydrolysis of the methionine-enkephalin tyrosyl-glycine peptide bond was blocked by the known aminopeptidase inhibitors bestatin and puromycin (IC50 1.2 +/- 0.4 and 4.3 +/- 2.4 microM, respectively) but not by either thiorphan or captopril. 3. Neither the storing (up to 60 days) nor the freezing and thawing (up to ten times during a 60 days periods) significantly changed the above kinetic parameters, showing the stability of the plasma methionine-enkephalin degrading aminopeptidase.

Phenylethylamine metabolism to tyramine by postmortem human brain preparations.

Human brain preparations obtained from either the putamen, thalamus, hippocampus or lateral occipital gyrus p-hydroxylate phenylethylamine to tyramine, a reaction carried out by a microsomal (100,000 xg pellet) membrane bound, NADPH-requiring enzyme. This is a minor metabolic pathway occurring in chronic psychiatric patients, as well as in age-comparable controls.

Nasogastric compared with nasoduodenal feeding in low birthweight infants.

One hundred successive infants weighing less than 1500 g at birth were allocated alternately to intermittent nasogastric or continuous nasoduodenal feeding regimens. Eighty were appropriate for gestational age, and of these 25 fed successfully by nasogastric tube and 16 tolerated nasoduodenal feeding until 1600 g. No significant differences in either calorie intake or growth rates were identified throughout the seven weeks of the study. Because of the increased complexity and radiological exposure involved with feeding transpylorically, nasogastric feeding may be preferred as a method of feeding the low birthweight infant.

Platelet monoamine oxidase activity and plasma levels of non-catecholic phenylethylamines in insulin-dependent diabetic subjects.

The activity of blood platelets monoamine oxidase (MAO) was significantly reduced in a group of insulin-dependent diabetics when compared to sex- and age-matched controls. This enzymatic change was accompanied by a dramatic increase in the plasma levels of phenylethylamine, whereas no significant changes were observed for the concentration of either p-tyramine or phenylethanolamine. Levels of the o- and m-isomers of tyramine were below detectable limits (less than 0.050 ng/ml). A possible role of the MAO/monoamine system in the pathophysiology of diabetes is discussed.

Water pollution and diseases in fish (an epizootiologic survey).

Three watersheds, varying from highly polluted or moderately polluted to essentially pollution-free, were surveyed to determine the frequency of fish disease. Over a five year period, it was found that a relationship existed between the level of pollution and frequency of disease. The occurrence rates of microbial and oncogenic diseases increased similarly in relation to increases in pollution in the waters. Since the water systems studied provide recreational opportunities for man, it is suggested that catching and subsequent ingesting of diseased fish from these waters present a health hazard.

Effects of monoamine oxidase inhibitors on the borohydride stabilizable binding of serotonin and tryptamine in brain.

The in vivo and in vitro effects of various monoamine oxidase inhibitors (MAOI) on the borohydride stabilizable finding of serotonin (5-HT) or tryptamine in brain was investigated. A significant correlation between the extent of Mao inhibition and the amount of stabilized binding of the indolealkylamines was demonstrated. All hydrazine-type MAOI and harmine, a reversible nonhydrazine-type MAOI, employed in vitro, were shown to decrease the binding. beta-Phenylisopropylhydrazine apparently blocks the receptor carbonyl groups in the brain in vitro as well as in vivo.

Studies on membrane receptor sites for serotonin in the brain.

The competitive effect of 5,6-dihydroxytryptamine, morphine and chlorpromazine on the binding of serotonin (5-HT) to rat brain slices was investigated. Ths busynaptosomal localization of the binding of morphine in bovine midbrain preparations was compared to that of 5-HT and found to be considerably higher. The condensation of 5-HT and tryptamine receptor carbonyl groups in brain with phenylisopropylhydrazine was shown in vitro and vivo. Membrane particles labeled with [14C] tryptamine or 5-HT in presence or absence of sodium borohydride (NaBH4) were extracted with chloroform-methanol (C-M) 2:1. The labeled proteolipid precipitated by ether from these extracts showed on electropherograms one single radioautographic spot which was more intense with samples treated with sodium borohydride. In column chromatography, the bound radioactivity peak eluted with the gel void volume, was associated with a protein peak. The eluted, lyophilized material of this fraction was extracted by chloroform methanol (2:1) thus suggesting its proteo-lipid nature.

Subsynaptosomal localization and biochemical characterization of serotonin binding sites in the brain.

The subsynaptosomal distribution of the borohydride stabilizable binding of serotonin (5-HT) in the brain was investigated using various enzyme markers, such as NAD glycohydrolase (NADase), Na+, K+-activated ATPase for synaptic membranes, and monoamine oxidase (MAO) for outer mitochondrial membranes. The gross distribution of the activity of NADase and Na+, K+-activated ATPase in various membrane fractions was found to parallel the distribution of 5-HT binding in these fractions. Radioactivity bound to brain fractions was extractable with chloroform-methanol (2:1). The membranous material was solubilized by chloroform-methanol (2:1) and the recovered material, suspended in 0.32 M sucrose was found to retain its 5-HT binding capacity. The protein-phospholipid nature of the binding subcellular macromolecule was demonstrated with proteolytic and lipolytic enzymes.