Behavioral responses of red hake,Urophycis chuss,to decreasing concentrations of dissolved oxygen

Synopsis Laboratory experiments were conducted to examine changes in behavior of red hake,Urophycis chuss, under decreasing concentrations of dissolved oxygen (DO). Since the ecological requirements of this species change with age, responses were measured for three different groups: (1) age 0+, = 89 mm total length (TL); (2) age 1+, = 238 mm TL; and (3) age 2–3+, = 397 mm TL. As DO decreased from 8–10 mg l^-1 to < 0.5 mg l^-1, changes were evident in active time, water column activity, range of horizontal movement, food searching, and agonistic behavior. Age 0+ fish were most sensitive, moving up into the water column and swimming continuously as DO levels fell below 4.2 mg l^-1. Age 2–3+ fish were the least responsive, remaining on the substrate and increasing only their range of movement at concentrations below 3 mg l^-1. Responses of age 1 + fish were variable, possibly reflecting a transition stage between the younger and older fish. Common to all groups was the decrease and eventual cessation of food searching.     

Sex determination from the radius in humans

The discriminatory capacity of the radius in sex determination was investigated in a Dutch skeletal collection of recent origin. Midshaft subperiosteal diameter, maximum length and maximum transverse distal width were measured from roentgenograms. The discriminatory capacity of the radius was found to be of the same order as that reported in the literature for the other long bones. Maximum transverse distal width showed the highest consistency (85%) between estimated and documented sex. This method requires only the presence of the distal fragment of the radius.     

Chromosome organisation in polyploid mouse trophoblast nuclei

At least one-third of mouse trophoblast cells undergo endoreduplication during the first half of gestation. It has been suggested that the endoreduplicated chromosomes may be polytenised. Here it is shown, using in situ hybridisation to the -1 antitrypsin genes, which map at a unique site, that while there is a tendency for duplicated chromosomes to cluster, this does not involve the complete fusion of replicated chromatids found in fully polytene chromosomes, and in a substantial proportion of homologues the sites on the chromosome arms corresponding to these genes are widely separated. The centromeres do not fuse into a single chromocentre but the possibility is not ruled out that individual chromosomes may be polytenised in the centromeric region. Evidence is also presented showing that endoreduplication in trophoblast nuclei is not accompanied by the formation of new prekinetochore structures, in contrast to the situation in polyploid mouse liver and C127 cells.     

Pathophysiology of pH and Ca2+ in bloodstream and brain

The highlights of the literature and our work on tetany and hyperventilation are reviewed. Our studies concern the following: (1) the changes of [Ca2+] in circulating plasma caused by respiratory and "metabolic" acidosis and alkalosis; (2) critical plasma [Ca2+] levels associated with signs of tetany and neuromuscular blockade; (3) changes in cerebral [Ca2+]o caused by hypo- and hyper-calcaemia, and the changes in cerebral [Ca2+]o and pHo caused by acute systemic acidosis and alkalosis; and (4) effects of changing [Ca2+]o and pHo levels on synaptic transmission in hippocampal formation. Our main conclusions are (1) changes of plasma [Ca2+] caused by "metabolic" pH changes are greater than those associated with varying CO2 concentration; (2) acute systemic [Ca2+] changes are associated with small cerebral [Ca2+]o changes; (3) the decreases in systemic and cerebral [Ca2+]o caused by hyperventilation are too small to account for the signs and symptoms of hypocapnic tetany; (4) moderate decrease of [Ca2+]o depresses and its increase enhances synaptic transmission in hippocampal formation; and (5) H+ ions in extracellular fluid have a weak depressant effect on neuronal excitability. CO2 is a strong depressant, which is only partly explained by the acidity of its solution. CO2 concentration is a significant factor in controlling cerebral function.     

Calcitonin gene-related peptide immunoreactivity in airway epithelial cells of the human fetus and infant

Summary Calcitonin gene-related peptide-immunoreactive cells were identified within the epithelium of distal conducting airways in the human fetus and infant. Several peptides and amines, including calcitonin, have been identified previously within a specific population of airway epithelial cells. These cells, referred to as pulmonary neuroendocrine cells, are postulated to be airway chemoreceptors responsible for changes in ventilation and perfusion in response to changes in airway gas composition. Calcitonin gene-related peptide immunoreactive cells could be identified throughout the period of development studies (20 weeks gestation to 3 months of age), but were present in only limited numbers in less than 50% of individuals (n=23). In contrast, large numbers of calcitonin gene-related peptide immunoreactive cells were identified in 100% of infants (1–3 months, n=5) with bronchopulmonary dysplasia. The differential processing of mRNA transcribed from the calcitonin gene in neural and non-neural tissue suggests that calcitonin, rather than calcitonin gene-related peptide, is the primary product of translation in pulmonary neuroendocrine cells. However, considering the potent vasodilatory and bronchoconstrictive effects of calcitonin gene-related peptide, its presence in pulmonary neuroendocrine cells, even in small amounts, may be important in controlling pulmonary vaso- and/or bronchomotor tone. The presence of large numbers of calcitonin gene-related peptide immunoreactive cells in infants with bronchopulmonary dysplasia suggests that calcitonin gene-related peptide may be one further agent contributing to the pulmonary pathophysiology seen in this disease.     

In vivo cytogenetic effects of cooked food mutagens

Using a variety of in vivo cytogenetic endpoints, we have investigated the effects of several compounds formed during the cooking of meat. C57Bl/6 mice were used to test for an increase in the frequency of sister-chromatid exchanges (SCEs), chromosomal aberrations, and micronucleated erythrocytes by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). MeIQx and DiMeIQx did not induce SCEs in mouse bone marrow cells. PhIP induced sister-chromatid exchanges, but not chromosomal aberrations in bone marrow. In peripheral blood lymphocytes, PhIP did induce aberrations at 100 mg/kg, the highest dose tested. PhIP induced a low but significantly increased frequency of micronuclei in normochromatic but not polychromatic erythrocytes in bone marrow and peripheral blood. However, dose responses were not observed. With the exception of the SCEs induced by PhIP, these results contrast with observations made in vitro, where these compounds were found to have significant genotoxicity in mammalian cells and a very high mutation frequency in prokaryotic systems.     

Phosphoribosyl pyrophosphate and the measurement on inorganic pyrophosphate in plant tissues

This work provides further evidence that plants contain appreciable amounts of inorganic pyrophosphate (PPi), and that breakdown of phosphoribosyl pyrophosphate (PPRibP) does not contribute significantly to the PPi detected in plant extracts. Inorganic pyrophosphate in extracts of the roots of Pisum sativum L., clubs of the spadices of Arum maculatum L., and the developing endosperm of Zea mays L. was assayed with pyrophosphate fructose 6-phosphate 1-phosphotransferase (EC 2.7.1.90), and with sulphate adenyltransferase (EC 2.7.7.4). The two different assays gave the same value for PPi content, and for recovery of added PPi. It was shown that PPRibP is converted to PPi during the extraction of PPi. However, the amounts of PPRibP in clubs of A. maculatum and the developing endosperm of Z. mays were negligible in comparison with the contents of PPi.Abbreviations EDTA ethylenediaminetetraacetic acid - PFK(PPi) pyrophosphate fructose 6-phosphate 1-phosphotransferase - PPi inorganic pyrophosphate - PPRibP phosphoribosyl pyrophosphate     

A ten-month study of endogenous testosterone levels and behaviour in outdoor-living female rhesus monkeys (Macaca mulatta)

Endogenous testosterone levels were measured in association with sexual, aggressive, and social/affiliative behaviors in 11 outdoor-housed female rhesus monkeys over a ten-month period. Several behaviors (sex directed toward the male, sex received from the male, aggression directed toward the male, submission directed toward the male, submission directed toward the female, and groom another female) were significantly (p<0.05) positively correlated with testosterone in from one to five females. No trends were strong enough across all females to suggest that any of these correlations have species-wide significance. Factor analysis revealed clearcut clusters of behaviors, but elevations in testosterone were not strongly associated with any of these clusters. It is concluded that endogenous testosterone levels have little measurable effect on overt behavior in female rhesus monkeys.