Re-establishment of the stress response in Gallus domesticus after hatching

Cold caused a hypercorticosteronaemia and hypothermia in the 2-day-old chick. Heat did not affect plasma corticosterone concentrations, despite the birds becoming hyperthermic. The 2-day-old chick has a lower resting concentration of corticosterone than the 1-day-old. The minimum effective dose of corticotrophin in stimulating a hypercorticosteronaemia was 0.5 IU/kg in the former, 1.0 IU/kg in the latter. It is concluded that stress non-responsiveness persists for about 48 hr after hatching and that it is due to a temporary inhibition of hypothalamic function.     

High-resolution gas chromatographic profiles of volatile organic compounds produced by microorganisms at refrigerated temperatures.

Three different strains of bacteria isolated from spoiled, uncooked chicken were grown in pure culture on Trypticase soy agar supplemented with yeast extract. The volatile organic compounds produced by each culture were concentrated on a porous polymer precolumn and analyzed by high-resolution gas chromatographic mass spectrometry. Twenty different compounds were identified. Both qualitative and quantitative differences in the chromatographic profiles from each culture were found.     

Cardiac Abnormalities in Poisoning with Tricyclic Antidepressants

Of 80 consecutive admissions to a general hospital for drug overdose, 10 had taken one or other of the tricyclic antidepressants. All 10 had abnormalities of cardiac conduction as shown by prolonged Q–T_e intervals, and eight had S–T segment and T-wave changes. Five of the 10 patients had arrhythmias and two of these died. Continuous electrocardiographic monitoring is recommended in patients with overdosage of tricyclic antidepressants.     

Impairments in availability of insulin to liver in vivo and in binding of insulin to purified hepatic plasma membrane during aging

The concentration of insulin in portal vein blood decreases 50–60% in fed or fasted rats as they age from 12- to 24-months. The binding capacity of purified hepatic plasma membrane for insulin decreases approximately 60% as rats age from 2- to 24-months, whereas the dissociation constant for insulin is not altered. It is proposed that these factors may contribute significantly to previously documented examples of age-dependent modifications in liver enzyme regulation.     

Recalcitrant High-Molecular-Weight Material, an Inhibitor of Microbial Metabolism in River Biofilms

Recalcitrant high (>1,000)-molecular-weight materials (>1K materials) have been proposed to inhibit the metabolic activity of river biofilms. Evidence is presented to support the hypothesis that the mode of action is through occlusion of the surface of the biofilm by recalcitrant >1K materials. The evidence includes the following. (i) The phenomenon was particularly prominent in brown-water rivers, which are rich in recalcitrant >1K material. (ii)Temporal changes in inhibition intensity were observed, which coincided with seasonal changes in the relative recalcitrance of river water >1K materials. (iii) Stores of intracellular carbon (poly-β-hydroxyalkanoates) were progressively compromised by increasing the supply of recalcitrant >1K materials. (iv) Nontoxic synthetic analogs of recalcitrant >1K materials were also demonstrated to be capable of producing an identical inhibitory effect. Finally, it was suggested that the application of recalcitrant >1K materials may represent a novel approach to the control of deleterious microbial communities.     

Human serum protein fractionation by gel filtration

The development of a quantitative immunological technique using polyvalent antiserum permits a more logical approach to the fractionation of complex protein mixtures. In this study whole serum was separated by conventional gel filtration and the fractions obtained were analysed. This demonstrates over 60 immunologically distinct serum proteins. Because the current terminology is inadequate to describe this number of proteins, a temporary numerical nomenclature has been used.     

Spermatozoa from the maned wolf (Chrysocyon brachyurus) display typical canid hyper-sensitivity to osmotic and freezing-induced injury,but respond favorably to dimethyl sulfoxide

We assessed the influences of medium osmolality, cryoprotectant and cooling and warming rate on maned wolf (Chrysocyon brachyurus) spermatozoa. Ejaculates were exposed to Ham’s F10 medium (isotonic control) or to this medium plus NaCl (350–1000 mOsm), sucrose (369 and 479 mOsm), 1 M glycerol (1086 mOsm) or dimethyl sulfoxide (Me₂SO, 1151 mOsm) for 10 min. Each sample then was diluted back into Ham’s medium and assessed for sperm motility and plasma membrane integrity. Although glycerol and Me₂SO had no influence (P > 0.05), NaCl and sucrose solutions affected sperm motility (P < 0.05), but not membrane integrity. Motility of sperm exposed to <600 mOsm NaCl or sucrose was less (P < 0.05) than fresh ejaculate, but comparable (P > 0.05) to the control. As osmolality of the NaCl solution increased, motility decreased to <5%. In a separate study, ejaculates were diluted in Test Yolk Buffer containing 1 M glycerol or Me₂SO and cooled from 5 °C to −120 °C at −57.8 °C, −124.2 °C or −67.0 °C/min, frozen in LN₂, thawed in a water bath for 30 s at 37 °C or 10 s at 50 °C, and then assessed for motility, plasma- and acrosomal membrane integrity. Cryopreservation markedly (P < 0.05) reduced sperm motility by 70% compared to fresh samples. Higher (P < 0.05) post-thaw motility (20.0 ± 1.9% versus 13.5 ± 2.1%) and membrane integrity (51.2 ± 1.7% versus 41.5 ± 2.2%) were observed in samples cryopreserved in Me₂SO than in glycerol. Cooling rates influenced survival of sperm cryopreserved in glycerol with −57.8 °C/min being advantageous (P < 0.05). The findings demonstrate that although maned wolf spermatozoa are similar to domestic dog sperm in their sensitivity to osmotic-induced motility damage, the plasma membranes tolerate dehydration, and the cells respond favorably to Me₂SO as a cryoprotectant.