Spermatogenesis, serum testosterone levels and immunolocalization of steroidogenic enzymes in the wild male Japanese black bear (Ursus thibetanus japonicus)

Twenty-one wild male Japanese black bears (Ursus thibetanus japonicus) were captured in the summer-autumn of 1998-2000 in the vicinity of Neo Village, Gifu Prefecture. Testes were measured, and testicular samples were biopsied and observed histologically. Four steroidogenic enzymes, i.e., cholesterol side-chain cleavage cytochrome P450 (P450scc), 3beta-hydroxysteroid dehydrogenase (3betaHSD), 17-alpha hydroxylase cytochrome P450 (P450c17), and aromatase cytochrome P450 (P450arom) were immunolocalized. Serum testosterone concentrations were measured by radioimmunoassay. Testis size changed little from 1-3 years of age, increased rapidly at 4 years, and attained its peak at 5 years. Serum testosterone concentrations ranged from 0.05 to 1.78 ng/m l, and the mean +/- standard deviation was 0.43 +/- 0.48 ng/ml. Age of sexual maturation in wild male Japanese black bears was estimated to be 3-4 years. Seasonal changes in spermatogenesis were obvious; active in June, July and August, degenerated by September. Leydig cells, Sertoli cells and germ cells have the capability of synthesizing androgen, and Leydig cells, Sertoli cells, spermatids and spermatogonia have the capability of synthesizing estrogen in Japanese black bears.     

NON-INVASIVE DIAGNOSIS OF ISCHEMIC BRAIN DAMAGE AFTER CARDIOPULMONARY RESUSCITATION IN DOGS BY USING TRANSCRANIAL DOPPLER ULTRASONOGRAPHY

We have attempted to identify whether it is possible to utilize transcranial Doppler ultrasonography to evaluate the brain damage that occurs after resuscitation from 3 min (control group) and 12 min (damage group) of cardiac arrest in dogs. In this study we used transcranial Doppler ultrasonography to follow the basilar arterial flow and middle cerebral arterial flow for 180 min following the induction of cardiac arrests. Two abnormal waveform patterns (the "to-and-fro" and "diastolic no-flow" patterns) were found in all dogs in the damage group whereas abnormal waveforms were not detected in the control group. Pathological diagnosis revealed that, compared with the control group, the damage group recognized ischemic alteration at the level of the hippocampus and caudate nucleus. In conclusion, this study shows that the basilar arterial flow of observed with transcranial Doppler ultrasonography may be use for the prediction of outcome and the diagnosis of brain damage in the dog.     

The effect of magmatic activity on hydrothermal venting along the superfast-spreading East pacific rise

A survey of hydrothermal activity along the superfast-spreading (approximately 150 millimeters per year) East Pacific Rise shows that hydrothermal plumes overlay approximately 60 percent of the ridge crest between 13 degrees 50' and 18 degrees 40'S, a plume abundance nearly twice that known from any other rige portion of comparable length. Plumes were most abundant where the axial cross section is inflated and an axial magma chamber is present. Plumes with high ratios of volatile ((3)He, CH(4), and H(2)S) to nonvolatile (Mn and Fe) species marked where hydrothermal circulation has been perturbed by recent magmatic activity. The high proportion of volatile-rich plumes observed implies that such episodes are more frequent here than on slower spreading ridges.     

Morphology and Distribution of Lamellar Corpuscles in the Mesentery of the Cat

Mesentery samples obtained from 13 mixed breed cats were stereoscopically and microscopically examined and yielded the following results. In the mesentery, lamellar corpuscles were densely distributed around blood vessels, with a mean number of 182.2 ± 20.9 and mean maximum and minimum diameters of 0.98 ± 0.18 mm and 0.54 ± 0.08 mm, respectively. While most lamellar corpuscles were isolated, some complex lamellar corpuscles were found in the mesentery. Lamellar corpuscles in the mesentery appear to serve more as internal receptors that detect changes in the internal environment than as external receptors. In addition, those found around blood vessels in the mesentery are likely to be involved in blood pressure regulation.     

A three-dimensional synthetic metallic crystal composed of single-component molecules

Molecular metals normally require charge transfer between two different chemical species. We prepared crystals of [Ni(tmdt)2] (tmdt, trimethylenetetrathiafulvalenedithiolate) and carried out crystal structure analyses and resistivity measurements. The analyses and measurements revealed that these single-component molecular crystals are metallic from room temperature down to 0.6 kelvin. Ab initio molecular orbital calculations suggested that pi molecular orbitals form conduction bands. The compact molecular arrangement, intermolecular overlap integrals of the highest occupied and lowest unoccupied molecular orbitals, and tight-binding electronic band structure calculation revealed that [Ni(tmdt)2] is a three-dimensional synthetic metal composed of planar molecules.     

Control of light emission by 3D photonic crystals

Three-dimensional (3D) photonic crystals containing artificial point defects have been fabricated to emit light at optical communications wavelengths. They were constructed by stacking 0.7-micrometer-period gallium arsenide striped layers, resulting in a 3D "woodpile" photonic crystal. Indium-gallium arsenide-phosphide quantum-well layers emitting at a wavelength of 1.55 micrometers were incorporated in the center of the crystal. Samples having up to nine stacked layers were constructed, and artificial point-defect cavities of different sizes were formed in the light-emitting layer. Light emission was suppressed in the photonic crystal regions, whereas cavity modes were successfully observed at the point defects and were size dependent.