Estimated feeding rates and energy requirements of gentoo penguins,Pygoscelis papua,at Macquarie Island

Summary Water and sodium turnovers of 6–7 week old gentoo penguin chicks and breeding adults were measured using isotopically labelled water and sodium. Influx rates for chicks averaged 188 ml·kg^-1·day^-1 and 13.9 mmol·kg^-1·day^-1 for water and sodium, respectively. Chicks consumed an estimated 228 g·kg^-1·day^-1 fresh food or 886 kJ kg^-1 day. These values correspond to 761 g·day^-1 or 2945 kJ·day^-1 for a gentoo chick mid-way through the growth period. Flux rates for adults attending chicks ranged from 199 to 428 ml·kg^-1·day^-1 for water and from 15 to 36 mmol·kg^-1·ay^-1 for sodium.     

Evaluation of eight and a half years of neonatal screening for haemoglobinopathies in Birmingham

A pilot neonatal screening programme for haemoglobinopathies linked with screening for phenylketonuria and congenital hypothyroidism was reviewed. During 1978 to December 1986 137 000 neonates were tested. There were improvements in the detection rate and accuracy of diagnosis for homozygotes and mixed heterozygotes, mainly associated with the introduction of citrate agarose gel electrophoresis as a follow up procedure on all specimens showing any abnormality on the initial cellulose acetate electrophoresis.We recommend that the programme is continued on a service basis.     

Nonenzymatic isolation and culture of adult islets from atrophic pancreata of copper-deficient rats: A morphologic analysis

Summary The purpose of this study was to develop a nonenzymatic method of isolating adult islets using atrophied pancreata from copper-deficient rats and to analyze their morphologic characteristics and behavior in culture. This unusual model of isolation was studied because islets remain intact in the course of dietary copper deficiency while the acinar glandular component of the pancreas undergoes selective atrophy and lipomatosis. Small fragments containing islets were readily microdissected from atrophied glands and placed in culture. Within 24 h the fragments congealed into small irregular- to spherical-shaped masses within which the darker profile of islets could be distinguished. Within a period of 3 to 5 d, islet tissue began to bud from the lipocytic mass until by Day 7 spherical aggregates of intact islet tissue separated from the residual fragments. Subsequent to further in vitro treatment, these islets could be maintained as free viable spherical masses if periodically agitated, as attached stationary islets which developed monolayer growth if left undisturbed and as aggregated masses of islet tissue forming megaislets if combined in small groups. Grouped islets treated with actinomycin D and cycloheximide did not exhibit aggregation when incubated with these inhibitors. This suggests that megaislet formation was an active process requiring protein-RNA synthesis rather than passive clumping or aggregation that can accompany metabolically altered or dying islets undergoing cellular shedding and adhesion. Immunohistochemical localization demonstrated that insulin, glucagon, somatostatin, and pancreatic polypeptide-immunoreactive cell types were present within the islets derived from this technique. The cellular topography of these islets was not unlike that described by others for islets cultured from enzymatic isolation. This culture model may serve as a resource for mature, viable islets isolated without mechanical or enzymatic disaggregation which can have attenuating effects on islet function. This work was supported by a research grant from the Diabetes Research and Education Foundation.     

Feedback delays and relaxation expectancies in EMG biofeedback

The use of noncontingent feedback controls in studies of the efficacy and process of electromyographic (EMG) biofeedback may yield results confounded by differential expectancies for relaxation. Furthermore, the role of expectancies in producing psychological and physical relaxation as well as reducing muscle activity is unclear. This study investigated the effects of feedback delays and induced relaxation expectancies on EMG activity and experienced relaxation. One hundred four non-clinical subjects participated in one auditory frontal EMG biofeedback training session. Subjects were assigned to one of four computerized feedback delay conditions (0.0037, 0.7493, 2.2481, 6.7444 s) and to one of two relaxation expectancy conditions (positive or negative). During 20 minutes of biofeedback training, all groups decreased frontal activity. Feedback delays interacted with training epochs in affecting EMG; the longest delay group reduced frontal activity more slowly than the shortest delay group during training. Positive relaxation expectancies produced greater experienced relaxation than did negative relaxation expectancies. Instrumental and expectancy factors in EMG biofeedback appear to operate independently of each other by reducing physiological activity and producing psychological relaxation respectively.This study was completed by the first author under the direction of the second author in partial fulfillment of the requirements for the Master of Arts degree. We gratefully acknowledge the computerization advice and assistance provided by Larry Wheeler, and the assistance in data collection provided by Dawn Dexter and Michael Winstanley.     

Daily relaxation modifies serum and salivary immunoglobulins and psychophysiologic symptom severity

This study investigated the effect of daily relaxation on concentrations of serum immunoglobulins A, G, and M and secretion rates of salivary immunoglobulin A (S-IgA). Twenty-four volunteers were randomly assigned to practice a relaxation technique daily for 3 weeks and 16 to a waiting list control condition. Blood and saliva samples were collected before and after a supervised 20-min relaxation session at the beginning and end of the 3-week practice period. S-IgA secretion rate increased significantly (p<.001) after 20 min of relaxation. A longer-term practice effect also occurred in that the increase in secretion rate in before to after relaxation samples was higher (p=.014) in subjects who had practiced relaxation once a day for 3 weeks than in waiting list control subjects practicing for the first time. Serum IgA (p<.001), IgG (p<.001), and igM (p<.05) increased significantly over the 3-week practice period. Relaxation may be a self-regulating strategy affecting both humoral and cellular divisions of the immune system.Parts of this paper were presented at the annual meeting of the Biofeedback Society of America, March 1987. Materials for the IgA assays were provided by Cooper Biomedical, Malvern, Pennsylvania.     

Interaction of opioid peptides and other drugs with multiple delta ncx binding sites in rat brain: further evidence for heterogeneity.

Recent pharmacological data strongly support the hypothesis of δ receptor subtypes as mediators of both supraspinal and spinal antinociception (δ₁ and δ₂ receptors). In vitro ligand binding data, which are fully supportive of the in vivo data, are still lacking. A previous study indicated that [³H][ -Ala², -Leu⁵]enkephalin labels two binding sites in membranes depleted of μ binding sites by pretreatment with the site-directed acylating agent, 2-(p-ethoxybenzyl)-1-diethylaminoethyl-5-isothiocyanatobenzimidazole-HCI (BIT). The main goal of the present study was to develop a ligand-selectivity profile of the two δ_ncx binding sites. The data indicated that naltrindole and oxymorphindole were relatively selective for site 1 (20-fold). [ -Ser²,Thr⁶]Enkephalin and deltorphin-II were only 2.7-fold and 2.2-fold selective for site 1. [ -Pen², -Pen⁵]Enkephalin and deltorphin-I were 80-fold and 38-fold selective for site 2.3-Iodo-Tyr- -Ala-Gly-Phe- -Leu was 52-fold selective for site 1. Morphine had moderate affinity for site 1 (K_i = 16 nM), and was about 11-fold selective for site 1. Thus, of the 10 drugs studied, only DPDPE and DELT-I were selective for site 2. Viewed collectively with other data, it is likely that the δ₁ receptor and the δ_ncx binding site are synonymous.     

Interactions between double-stranded RNA regulators and the protein kinase DAI.

The interferon-induced protein kinase DAI, the double-stranded RNA (dsRNA)-activated inhibitor of translation, plays a key role in regulating protein synthesis in higher cells. Once activated, in a process that involves autophosphorylation, it phosphorylates the initiation factor eIF-2, leading to inhibition of polypeptide chain initiation. The activity of DAI is controlled by RNA regulators, including dsRNA activators and highly structured single-stranded RNAs which block activation by dsRNA. To elucidate the mechanism of activation, we studied the interaction of DAI with RNA duplexes of discrete sizes. Molecules shorter than 30 bp fail to bind stably and do not activate the enzyme, but at high concentrations they prevent activation by long dsRNA. Molecules longer than 30 bp bind and activate the enzyme, with an efficiency that increases with increasing chain length, reaching a maximum at about 85 bp. These dsRNAs fail to activate at high concentrations and also prevent activation by long dsRNA. Analysis of complexes between dsRNA and DAI suggests that at maximal packing the enzyme interacts with as little as a single helical turn of dsRNA (11 bp) but under conditions that allow activation the binding site protects about 80 bp of duplex. When the RNA-binding site is fully occupied with an RNA activator, the complex appears to undergo a conformational change.     

Glomerular bypass shunts and distribution of glomeruli in the kidney of the lesser spotted dogfish,Scyliorhinus caniculus

Summary Scanning electron microscopy of corroded resin casts of the renal vasculature of Scyliorhinus caniculus has revealed a novel vascular pathway arising from the afferent arteriole and bypassing the glomerulus. This glomerulus bypass shunt occurred in 36% of the glomerular casts examined. The shunt ran to join a peritubular network of capillaries and thereby offers the potential to vary the degree of glomerular perfusion and control the proportion of active glomeruli. In 29% of glomeruli two efferent arterioles drained the capillary knot. Glomeruli were located close to the dorsal margin of the posterior mass of the kidney, and towards the lateral edge of the anterior lobes of the kidney of female dogfish. In male dogfish, glomeruli were evenly distributed through the posterior mass of kidney, while in female dogfish 89% of glomeruli occurred in the posterior mass and 11% of glomeruli were located within the small anterior lobes.