Ultrastructure and ATPase activity of the rectal gland of the chondrichthyean fish Hydrolagus colliei (Holocephali)

Summary The anatomy, histology, ultrastructure and ATPase activity of the intramural rectal gland of the chondrichthyean Hydrolagus colliei, are described. The cells of the rectal gland of Hydrolagus demonstrate the same well developed lateral and basal cisternae, elongate mitochondria and luminal border as those of their elasmobranch counterparts. ATPase activity within the rectal gland of Hydrolagus is as intense as that in a number of elasmobranchs examined in the course of the study. Despite its primitive intramural location the rectal gland of Hydrolagus respresents a homolog of the more specialized and better known elasmobranch gland and appears as well suited for cation excretion.     

Mortality in Grey seal pups: incidence and causes

Pup production and mortality of beach breeding Grey seals was studied at two contrasting types of rookery, the cliff-bound island of Ramsey, Dyfed, and the low, grassy island of Auskerry, Orkney. Thirty-five per cent of pups died on Ramsey compared with 14 % on Auskerry. Almost half of the Ramsey mortality was accounted for by animals being lost from the beaches so that they were not available for analysis. The main proximate causes of death revealed by post-mortem examination were starvation and infections. The other conditions which accounted for a small proportion of deaths were drowning, trauma, non-viability, stillbirths, atelectasis, dystokia and heart abnormality. Certain pathogens associated with disease were common to both sites, while others were specific to Ramsey or Auskerry.
The most important ultimate cause of pup deaths appeared to be failure of the mother/pup bond. The differences in levels of mortality between the sites is thought to be due to differences in the topography of the beaches. Pup survival on the narrow cliff-bound beaches, or in caves, on Ramsey was reduced either directly through pups being washed off, or indirectly by overcrowding of animals at high tide.     

Synergistic effect of ribose and 2-deoxy-ribose with nutrition and auxin in rooting hypocotyl cuttings of Phaseolus mungo

Exogenously supplied ribose and deoxyribose in a medium containingsucrose+ IAA considerably enhanced the formation of roots onhypocotyl cuttings of Phaseolus mungo with intact apex andleaves.The effect increased with increasing concentration of pentosesugars and was more pronounced with deoxyribose than with ribosesugar. (Received October 25, 1975; )     

Hypoxanthine-guanine phosphoribosyltransferase: Mosaicism in the peripheral erythrocytes of a heterozygote for a normal and a mutant enzyme

A mutant form of erythrocyte hypoxanthine-guanine phosphoribosyltransferase with an abnormal isoenzyme pattern was found in a patient with a partial enzyme deficiency and X-linked gout. This abnormal pattern was a marker for the mutant enzyme in hemolysate from the heterozygote for the enzyme deficiency.These studies were generously supported by the Medical Research Council of Canada (MRC # MA4758) and the Canadian Arthritis and Rheumatism Society.     

Prostaglandin biosynthesis and stimulation of cyclic AMP in primary monolayer cultures of epithelial cells from mouse mammary gland

Cyclic AMP levels in primary monolayer cultures of epithelial cells prepared from mid-pregnant mice are stimulated by prostaglandin E₁ and E₂. Prostaglandin F_1α and F_2α have only a slight effect upon cyclic AMP levels. In the absence of phosphodiesterase inhibitors the rise in cyclic AMP produced by PGE₁ is only transient and the levels return to normal within 30 minutes. High concentrations (16 mM) of theophylline are needed to prevent this decline, suggesting that the phosphodiesterase activity of epithelial cells in culture is high. However, theophylline alone produced only a small increase in basal cyclic AMP levels even over a 2-hour period indicating that basal cyclic AMP is turned over more slowly than cyclic AMP produced in response to stimulation with PGE₁.Both PGE and PGF synthesis were monitored using radioimmunoassay procedures previously reported. The observed levels were found to decrease as cell density increased and were sensitive to the addition of agents such as collagen and naproxen.     

Making Smart Social Judgments Takes Time: Infants' Recruitment of Goal Information When Generating Action Predictions

Previous research has shown that young infants perceive others'' actions as structured by goals. One open question is whether the recruitment of this understanding when predicting others'' actions imposes a cognitive challenge for young infants. The current study explored infants'' ability to utilize their knowledge of others'' goals to rapidly predict future behavior in complex social environments and distinguish goal-directed actions from other kinds of movements. Fifteen-month-olds (N = 40) viewed videos of an actor engaged in either a goal-directed (grasping) or an ambiguous (brushing the back of her hand) action on a Tobii eye-tracker. At test, critical elements of the scene were changed and infants'' predictive fixations were examined to determine whether they relied on goal information to anticipate the actor''s future behavior. Results revealed that infants reliably generated goal-based visual predictions for the grasping action, but not for the back-of-hand behavior. Moreover, response latencies were longer for goal-based predictions than for location-based predictions, suggesting that goal-based predictions are cognitively taxing. Analyses of areas of interest indicated that heightened attention to the overall scene, as opposed to specific patterns of attention, was the critical indicator of successful judgments regarding an actor''s future goal-directed behavior. These findings shed light on the processes that support “smart” social behavior in infants, as it may be a challenge for young infants to use information about others'' intentions to inform rapid predictions.     

Excess Maternal Salt Intake Produces Sex-Specific Hypertension in Offspring: Putative Roles for Kidney and Gastrointestinal Sodium Handling

Hypertension is common and contributes, via cardiovascular disease, towards a large proportion of adult deaths in the Western World. High salt intake leads to high blood pressure, even when occurring prior to birth – a mechanism purported to reside in altered kidney development and later function. Using a combination of in vitro and in vivo approaches we tested whether increased maternal salt intake influences fetal kidney development to render the adult individual more susceptible to salt retention and hypertension. We found that salt-loaded pregnant rat dams were hypernatraemic at day 20 gestation (147±5 vs. 128±5 mmoles/L). Increased extracellular salt impeded murine kidney development in vitro, but had little effect in vivo. Kidneys of the adult offspring had few structural or functional abnormalities, but male and female offspring were hypernatraemic (166±4 vs. 149±2 mmoles/L), with a marked increase in plasma corticosterone (e.g. male offspring; 11.9 [9.3–14.8] vs. 2.8 [2.0–8.3] nmol/L median [IQR]). Furthermore, adult male, but not female, offspring had higher mean arterial blood pressure (effect size, +16 [9–21] mm Hg; mean [95% C.I.]. With no clear indication that the kidneys of salt-exposed offspring retained more sodium per se, we conducted a preliminary investigation of their gastrointestinal electrolyte handling and found increased expression of proximal colon solute carrier family 9 (sodium/hydrogen exchanger), member 3 (SLC9A3) together with altered faecal characteristics and electrolyte handling, relative to control offspring. On the basis of these data we suggest that excess salt exposure, via maternal diet, at a vulnerable period of brain and gut development in the rat neonate lays the foundation for sustained increases in blood pressure later in life. Hence, our evidence further supports the argument that excess dietary salt should be avoided per se, particularly in the range of foods consumed by physiologically immature young.     

Primate Location Preference in a Double-Tier Cage: The Effects of Illumination and Cage Height

Nonhuman primates are frequently housed in double-tier arrangements with significant differences between the environments of the upper and lower-row cages. Although several studies have investigated whether this arrangement alters monkeys' behavior, no studies have addressed the two most notable differences, light and height, individually to determine their relative importance. This experiment examined how rhesus and long-tailed macaques allocated their time between the upper and lower-row cages of a 1-over-1 apartment module under different lighting conditions. In Condition A, monkeys' baseline degree of preference for the upper- and lower-row was tested. In Condition B, the lighting environment was reversed by limiting illumination in the upper-row cage and increasing illumination in the lower-row cage. In both conditions, monkeys spent more time in the upper-row cage, thus indicating a strong preference for elevation regardless of illumination. The amount of time that monkeys spent in the lower-row cage increased by 7% under reversed lighting, but this trend was not significant. These results corroborate the importance of providing captive primates with access to elevated areas.