Sex differences in vasopressin neurons in the bed nucleus of the stria terminalis by in situ hybridization

To determine whether a sex difference exists in the biosynthetic capacity of vasopressingergic (AVP) neurons in the bed nucleus of the stria terminalis (BNST), we have used in situ hybridization and quantitative autoradiography to measure propressophysin messenger RNA levels in these cells from adult male and female rats. We have found that significantly more (p less than 0.01) neurons are labeled in male rats than in female rats and that these labeled cells averaged more grains/cell (p less than 0.05) in males than in females. Therefore, the sexual dimorphism of AVP pathways in the BNST and lateral septum recently shown by immunohistochemistry results from a sex difference in the biosynthetic capacity of these AVP neurons.     

High density lipoprotein particle size distribution in subjects with obstructive jaundice

High density lipoproteins (HDL) from 14 patients with obstructive jaundice were examined by gradient gel electrophoresis to determine the effect of obstruction on particle size distribution. HDL from 7 of these patients were fractionated by gel permeation chromatography and further characterized by electron microscopy, SDS gel electrophoresis, apolipoprotein A-I and apolipoprotein A-II immunoturbidimetry, and analysis of chemical composition. In addition, lecithin:cholesterol acyltransferase (LCAT) activity was measured and correlated with plasma apolipoprotein A-I concentration and particle size distribution. HDL were abnormal in all patients regardless of severity, cause, or duration of obstruction. The major HDL subfraction in normal subjects, HDL3a (radius 4.1-4.3 nm) was either absent or considerably diminished, and HDL2b (radius 5.3 nm) was also frequently absent. Very small particles comparable in size to normal HDL3c (radius 3.8 nm) were prominent. In patients with a bilirubin concentration greater than 250 mumol/l, normal HDL had totally disappeared and were replaced by large discoidal particles of radius 8.5 nm and small spherical particles of radius 3.6-3.7 nm. Both populations of particles were markedly depleted of cholesteryl ester and enriched in free cholesterol and phospholipid. The discoidal particles were rich in apolipoproteins E, A-I, A-II, and C, while the small spherical particles contained predominantly apolipoprotein A-I. LCAT activity was diminished in all subjects to 8-54% of normal, and was strongly positively correlated (r = 0.91 P less than 0.05) with plasma apolipoprotein A-I levels.     

Songs of American Redstarts (Setophaga ruticilla): Sequencing Rules and their Relationships to Repertoire Size

In order to determine the rules of sequencing of songs used by American redstarts, we related Markovian and hierarchical models to recordings obtained from free-living males. In the smaller repertoires of three or four songs, low order Markov chain models fitted the data. 9 of the 10 sequences so examined were first-order, and the last was second-order. Larger repertoires of 6 and 8 songs were hierarchical in organization with subsets of songs having independent sequencing rules. Most samples of singing were stationary in their transition rules over periods of several days: non-stationarity was sometimes associated with a change in the number of songs forming the sequence, or in repetitions of songs. We examine causal models of song sequencing and conclude that our results generally favor competition models, although some sequential dependencies may also apply. Hierarchical organization in the serial repertoires of American redstarts may reflect developmental influences rather than effects of repertoire size itself.     

Particle sources and trace element reactivity in the Humber plume

Samples of suspended particulate matter (SPM) collected from the Humber Estuary had higher concentrations of particulate metals than SPM from Holderness coastal waters (U.K.). Characterised SPM from both sources was used in laboratory experiments involving the uptake of radiotracer¹⁰⁹Cd,¹³⁷Cs,⁵⁴Mn and⁶⁵Zn. Kinetic experiments, over five days, showed that the rate and extent of uptake was highly dependent on particle type, with¹⁰⁹Cd,⁵⁴Mn and⁶⁵Zn being more reactive with Humber Estuary particles than those from Holderness and¹³⁷Cs having the opposite trend. Adsorption experiments were also carried out on suspensions in which SPM from the Humber Estuary and Holderness coastal water were mixed in various proportions. These experiments revealed that K_d for⁶⁵Zn increased linearly with the proportion of Humber SPM, K_d for¹³⁷Cs decreased linearly with increase in Humber SPM and K_d for⁵⁴Mn and¹⁰⁹Cd displayed non-linear behaviour. The results of the study were used to develop an algorithm for predicting the partition coefficients in the Humber Plume based on the extent of particle mixing from the two source regions. The use of^206/207Pb ratios in determining the extent of particle mixing is discussed, along with the application of the algorithm to the modelling of particulate trace metal behaviour in the Humber-Wash coastal zone.     

Yeast hexokinase mutants.

Using yeast mutants, it is shown that growth on glucose occurs even in the absence of both hexokinase A and hexokinase B; fructose growth requires at least one of these two enzymes. Expression of hexokinase A and of glucokinase seem to be regulated.     

An Automated Technique for the Radiographic Determination of Bone Age

We have developed an automated procedure for determining bone-age in the monkey, Macaca fascicularis. The status of epiphysial junctions and sesamoids were determined from radiographs. Epiphyses were scored as either open or closed, and sesamoids were scored as either present or absent. Bone-age was calculated by a computer program that stored and used a data base of probabilities for epiphysial closure and sesamoid appearance. The simplicity of scoring, combined with the speed and accuracy of the calculations, make this technique potentially adaptable for use in a variety of primate species.