Experimental 3-D digital TV studio

The Michelangelo Project at the University of Glasgow has developed an experimental three-dimensional television studio. This uses 24 video cameras and parallel computers to capture moving three-dimensional models of human actors. This allows the capture in real time of the appearance and three-dimensional positions of a human actor. It does this using stereo imaging techniques that have been under development at the University of Glasgow for several years. The development of the studio has thrown up many technical problems which are still to be fully resolved, nonetheless it is already producing convincing animated sequences.     

Voluntary waiting period management practices in dairy herds participating in a progeny test program

A survey was mailed to approximately 4,000 herds participating in a young sire progeny test program to estimate the percentage of herds that selectively alter the voluntary waiting period (VWP) for individual cows or groups of cows. Responses were received from 673 herds (17%; 583 Holsteins, 55 Jerseys, 35 other dairy breeds). The mean VWP cited by respondents was 56 ± 0.6 d (range = 30 to 90 d) and did not differ by breed. Among responding herds, 64% (432/673) indicated the VWP was selectively altered for one or more reasons. The most frequently cited reasons for altering the VWP were postpartum health (50%), season (18%), milk yield (18%), parity (14%), and other reasons (14%). In Holstein herds that altered the VWP based on milk yield, the highest production group averaged 14 more days to first service than the lowest production group (≥40 vs. <20 kg of energy-corrected milk, respectively). In contrast, days to first service were nearly identical for all production groups in Holstein herds that did not vary the VWP based on milk yield. In conclusion, management decisions to selectively alter the VWP led to differences in days to first service and may have a confounding effect on genetic estimates of daughter fertility. Opportunities to improve the accuracy of daughter pregnancy rate estimates may reside in models that adjust for VWP management decisions on a within-herd basis.     

L-ornithine vs. L-ornithine-L-aspartate as a treatment for hyperammonemia-induced encephalopathy in rats

BACKGROUND/AIMS: The effect of L-ornithine (ORN) and L-ornithine-L-aspartate (OA) therapy on "extracerebral" nitrogen metabolism, brain metabolism and neurotransmission has been investigated in portacaval shunted rats with hyperammonemia-induced encephalopathy. METHODS: One day before ammonium-acetate infusion, a portacaval shunt was performed in three experimental groups: 1-control rats, 2-ORN-treated rats and 3-OA-treated rats. Ammonium-acetate was given as an intravenous bolus injection (0.4 mmol.kg bw-1) followed by a constant infusion (1.9 mmol.kg bw-1.h-1) so that steady-state blood ammonia concentrations (500-800 microM) were obtained in the course of 5 h. After 1 h, ammonium-acetate infusion, either L-ornithine or L-ornithine-L-aspartate, was infused for the next 4 h (3.0 mmol.kg bw-1.h-1) in the treated groups. The following parameters were measured: clinical grade of encephalopathy, EEG activity (n = 10 - 20/group), amino acids in plasma (n = 10 - 20/group) and brain dialysate (n = 5 - 9/group), and brain metabolites obtained by in vivo cerebral 1H-MRS (n = 4 - 6/group). RESULTS: ORN and OA treatment resulted in significantly lower blood (34% and 39%) and brain (42% and 22%) ammonia concentrations, significantly higher urea production (39% and 86%) and significantly smaller increases in brain glutamine and lactate concentrations than in controls. These changes were associated with a significantly smaller increase in clinical grade of encephalopathy in ORN- and OA-treated rats, and a significant improvement in EEG activity in ORN-treated rats. OA-treated rats showed a significant increase in aspartate and glutamate concentrations in brain dialysate. CONCLUSIONS: The beneficial effects of both treatments on the manifestations of hyperammonemia-induced encephalopathy can be explained by a reduction in blood and brain ammonia concentrations. It is suggested that when OA is administered, the effect of ornithine is partly counteracted by aspartate, inducing high brain extracellular concentrations of the two excitatory amino acids glutamate and aspartate, and perhaps causing overstimulation of NMDA receptors.     

Sex differences in endocrine and psychological responses to psychosocial stress in healthy elderly subjects and the impact of a 2-week dehydroepiandrosterone treatment

Evidence from animal as well as human studies has suggested that significant sex differences exist in hypothalamus-pituitary-adrenal axis (HPA) activity. As gonadal steroids could be important modulators of HPA sex differences, stress responses were investigated in subjects of advanced age after dehydroepiandrosterone (DHEA) or placebo treatment. After a 2-week treatment with 50 mg DHEA daily or placebo, 75 men and women (mean age, 67.6 yr) were exposed to the Trier Social Stress Test (TSST). The TSST is a brief psychosocial stress that consists of a free speech and mental arithmetic task in front of an audience. The results show that the TSST induced significant increases in ACTH, salivary free cortisol, total plasma cortisol, norepinephrine, and heart rates (all P < 0.0001) as well as decreased positive affect in the elderly (P = 0.0009). Men showed larger stress responses in ACTH (P = 0.004), salivary free cortisol (P = 0.044), and plasma total cortisol (P = 0.076) compared to women. No sex differences were observed in norepinephrine, epinephrine, or heart rate responses. In contrast to ACTH and cortisol response differences, women reported that they were significantly more stressed by the TSST than men (P = 0.0051). Women treated with DHEA showed ACTH stress responses similar to those of men, but significantly enhanced compared to those of women taking placebos (P < 0.009). No other stress response differences emerged between DHEA and placebo groups. Finally, DHEA treatment did not result in an improvement of subjective well-being. We conclude that elderly men show larger HPA responses than women to psychosocial stress, as studied in the TSST. Estrogen effects on hypothalamic CRF-producing neurons might be responsible for these sex differences.     

Methodological aspects of Klebsiella pneumoniae serotyping and its use for characterization of clinical isolates

The method for serological typing of Klebsiella pneumoniae making use of Russian commercial K-sera manufactured by the Ilya Metchnikoff firm has been used to characterize 85 strains isolated from newborns at an obstetrical hospital and department of newborn diseases and from children with acute enteric infections hospitalized at the hospital for infectious diseases. The authors emphasize that their methods of serotyping are to be accurately performed, specifically, the selection of capsular forms and identification of serovars in strains which can be agglutinated by several sera. Serovars were identified by the proposed serotyping method in 89.4% of the studied strains. A wide spectrum of K-serovars typical of this or that hospital has been defined for each institution. K. pneumoniae K2 predominated in the obstetrical hospital, K. pneumoniae K24 and K25 prevailed in department for newborn diseases, and the K14 variant in the infectious diseases hospital.