Oxygen Transport System in Children Living in the Russian Far North

We studied 654 healthy ten- to twelve-year-old children living in the Russian Far North (Taimyr peninsula) and in Siberia (town of Krasnoyarsk). The state of the body oxygenation and the systems responsible for oxygen delivery were studied according to the length of time living in the Russian Far North and season of the year. An examination of newcomer children revealed the following changes during the first year of living in the Russian Far North: an increased respiration rate and changes in its circadian rhythm; an increase in the heart rate, cardiac output, and cardiac index; an increase in the mean corpuscular volume in the red blood system; the activation of lipid peroxidation, and the changes in electrolyte balance of cells. The control mechanisms of oxygen transport system gradually stabilized during the ages of two to five years. In children living more than five years in the Russian Far North, the increased oxygen demand was met by the activation of cardiovascular and red blood systems aimed at more effective and adequate oxygen delivery to tissues.     

Winter food availability limits winter survival of Mongolian gerbils (<Emphasis Type="Italic">Meriones unguiculatus</Emphasis>)

Food availability is important to the dynamics of animal social organizations or populations. However, the role of winter food availability in animal population dynamics is still controversial. We carried out an experimental study to test Lack’s hypothesis that reduced food in winter limits survival and spring numbers of breeding individuals of social groups, using the Mongolian gerbil (Meriones unguiculatus) as model species. We established 24 gerbil social groups in 24, 10 × 10 m, pens in September 2008. We provided wheat seeds as supplemental food in 12 enclosures from September 2008 to March 2009; the other 12 enclosures, not provided with supplemental food, served as controls. We live-trapped gerbils at a 2-week interval from September to April. Supplemental food during winter increased biweekly survival by 10% relative to that in control groups. Only four control social groups survived to the end of our study whereas all 12 food-supplemented social groups survived through our study period. Supplemental food also increased cumulative numbers of recruits and group sizes of gerbils. We conclude that winter food availability limits winter survival and spring social groups or population sizes of Mongolian gerbils.     

Effect of menthol on human temperature sensitivity

Application of 1% methol, which, along with cold, activates specific thermosensitive ionic channels, changes the number of functioning cold receptors on the skin of the forearm similarly to the cold exposure test; however, it does not affect the number of heat receptors and does not significantly change the threshold of cold sensation. Group variants of responses to menthol that indicate individual differences in the sensitivity of skin receptors to the effects of methol and cold have been found. The results obtained give grounds to suggest that, from the variant of response to menthol (a decrease, increase, or absence of changes in the number of functioning cold receptors 5 min after menthol application), it is possible to predict specific features of response to cold.     

Lipase-catalyzed transamidation of non-activated amides in organic solvent

A novel biocatalytic reaction of transamidation of non-activated amides with amines is reported. Among 45 different lipolytic and proteolytic enzymes tested, only the lipase from Candida antarcticawas able to catalyze this reaction. The reaction proceeded with up to ca. 80% conversion in anhydrous methyl tert-butyl ether and worked with both N-substituted and unsubstituted amides. The biocatalytic transamidation is an equilibrium process and, therefore, higher conversions to the desired amide were achieved by using increased concentrations of the amine nucleophile.     

Hypophysiotropic neurons in the goldfish hypothalamus demonstrated by retrograde transport of horseradish peroxidase

Summary The horseradish-peroxidase (HRP) technique was used to visualize the cell bodies of axons projecting to the goldfish pituitary. Following intravenous injections of HRP, HRP reaction products were observed in axons of the rostral pars distalis, proximal pars distalis, neurointermediate lobe, pituitary stalk and in axons coursing from the pituitary into the hypothalamus. HRP-labelled cells in the brain were localized in two regions only — the nucleus preopticus (NPO) pars magnocellularis and pars parvocellularis, and the nucleus lateralis tuberis (NLT) of the hypothalamus. These observations suggest that the NPO and NLT are the source of the neurosecretory innervation of the goldfish pituitary.     

Morphological changes in the cochlear nuclear complex in primate phylogeny and development

The primate cochlear nuclear complex exhibits several characteristic morphological differences in the various primate families from Lorisidae through Hominidae. The most striking differences occur in the organization of the dorsal cochlear nucleus in which the laminar pattern becomes progressively obscured. Granule cells form an external granular layer as well as being intermixed within the molecular and pyramidal layers in slow lorises and squirrel and rhesus monkeys. Whereas a prominent external granular layer remains in chimpanzees, granule cells are scant in other portions of the nucleus. Human adults lack an external granular layer. A small number of granule cells occur but with inconstant distribution. Primates lack the linear array of pyramidal cells oriented perpendicularly to the epithelial surface as seen in cats. The granule cell layer exhibits similar regression in development of the human cochlear complex. The external granular layer is prominent in the fetus but rapidly decreases in size after birth. It achieves its adult form prior to 18 months. The data suggest that neuronal attrition, or programmed cell death, may be the major mechanism accounting for the alterations that occur in the human granule cell layer. Other differences in cytoarchitecture, within the great apes and humans, include decreases in the small and giant cell populations of the cochlear complex. These changes, in consort with the organizational changes and reduction of granule cells as noted above, suggest a trend towards reduced intranuclear integration at the level of the cochlear nucleus coupled with encephalization of the auditory system.     

Avian hepatic T3 generation by 5'-monodeiodination: characterization of two enzymatic pathways and the effects of goitrogens

The enzymatic nature of 5'-monodeiodination (5'-D) in avian liver homogenates was demonstrated by abolishment of activity by iopanoic acid (IOP). T3 production from T4 was dependent on enzyme and substrate concentrations, incubation time, incubation temperature, and pH. Two pathways of 5'-D activity were present in avian liver and exhibited characteristics similar to those described in mammalian tissues. Type II activity was identified as propylthiouracil (PTU)-insensitive activity. Type I (PTU-sensitive) was determined by difference between Total and Type II. Km values were 1.58 microM T4 for Total activity and 0.90 nM T4 for Type II, corresponding to the characteristics of the mammalian pathways. The effects of goitrogens on avian hepatic 5'-D were equivalent to those reported for the mammalian enzyme.