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Biomedical subjects

H Shen

Publications and source records attributed to H Shen.

353 records · Page 20Linked to original sources
PubMed1984

Influence of vitamin deficiency and level of dietary protein on the incidence of leg problems in broiler chicks.

Diets containing either 22 or 30% protein were supplemented with a vitamin mix where one of 11 added vitamins were singly eliminated from the mix. Male, day-old broilers were fed these diets to 3 weeks of age, and weight gains, feed utilization, and leg problems were recorded. In general, the higher protein diet did not result in a greater incidence of leg problems; however, it did alter performance of several of the vitamin-deficient diets as compared to the lower protein diet. Of the 11 vitamins studied only nonsupplementation of riboflavin markedly reduced weight gain and feed utilization during the 3-week feeding period. However, deletions of vitamin D3 and niacin also resulted in reduced performance. Riboflavin deficiency resulted in paralysis in a high percentage of the birds while the niacin-deficient diet gave a high percentage of birds with deformed legs and problems of mobility. The results demonstrate that a high incidence of leg problems may be present in a flock with little or no signs of reduced gain or feed utilization. The data suggest that under practical conditions the elimination of a particular vitamin from a diet for a short period of time would probably have a negligible effect on performance.

Animals↗
PubMed1980

Alterations in levels of thyrotrophin releasing hormone and rates of hormone degradation in hypothalamic tissue of the developing rat.

Developmental changes in levels of hypothalamic thyrotrophin releasing hormone (TRH) and the role that hypothalamic degrading enzymes may play in these alterations were investigated. Levels of TRH in male and female fetal rats and in male neonatal rats were measured by radioimmunoassay. The hormone content of the hypothalamus was shown to increase from less than 1 ng at 1--4 days of age to approximately 10 ng at 20 days of age. Thereafter, the content of TRH declined to the adult level of about 5 ng. The ability of fractionated hypothalamic homogenates to degrade TRH was measured over the same time. The 27 000 g supernatant fraction contained a degrading activity that yielded only radiolabelled deamido-TRH upon incubation with [L-proline 2,3-3H]TRH. The corresponding particulate fraction contained at least two distinct TRH degrading activities as determined by the number of metabolites present. Changes in rates of degradation were not large enough to account for the differences observed in levels of TRH.

Animals↗
PubMed1976

A flow calorimetric method of determining electron beam energy.

The construction of an adiabatic flow calorimeter using water as the working substance is described. It is shown that at high dose rates the heat defect due to chemical reactions in water is small (of the order of 0-3%) and that under high dose rate conditions flow calorimetry can be used as a method of measuring the energy of high intensity electron beams. Measurements made with a 15 MeV linear accelerator are reported and compared with magnetic measurements.

Calorimetry↗
PubMedDate not supplied

Correlation of gene structure and psychophysical measurement in red-green color vision deficiency in Chinese.

PURPOSE: To study the correlation of genotype for X-linked red-green gene array with color vision phenotype in 58 subjects with red-green color vision deficiency. METHODS: The molecular structure of red and green pigment genes on 58 X chromosomes was studied exon-by-exon by using heteroduplex-SSCP analysis and sequencing. The color vision of these subjects was determined by a Neitz anomaloscope. RESULTS: Variations in the red and green pigment genes were detected in 43 subjects and a hybrid gene was found in 27 subjects. About 50% of the fusion sites occurred at intron 2-3. All 3 anomalous trichromats with intron 4 fusion were mild type but another 3 with intron 2-3 fusion were severe type. No subjects with mild type of color vision defects had a fusion site at intron 2-3 or its upstream. Three subjects with complete deletion of the green pigment gene manifested deuteranomaly. CONCLUSIONS: Protans can be differentiated from deutans on the basis of genotype. It is still difficult to establish a clear correlation of different anomalous trichromats with genotype. The fusion site of a hybrid gene affects the phenotype to some degree. Intron 2-3 is the common place for gene crossover.

Blotting, Southern↗
PubMedDate not supplied

Linkage disequilibrium and association with methamphetamine dependence/psychosis of mu-opioid receptor gene polymorphisms.

Several studies indicate that the mu-opioid receptor plays a role in addiction not only to opiate drugs but also to alcohol and non-opiate addictive drugs. Our studies aim to reveal the associations between gene polymorphisms and methamphetamine (MAP) dependence/psychosis. We newly identified several polymorphisms and four substantial linkage disequilibrium (LD) blocks in the mu-opioid receptor (OPRM1) gene. We found significant differences in both genotype and allele frequencies of the single-nucleotide polymorphism (SNP) IVS2+G691C between control (n=232) and MAP-dependent/psychotic patients (n=128). There was also a significant association between IVS2+G691C and patients with transient psychosis. These results suggest that the OPRM1 gene variations may be a factor in development and prognosis of MAP psychosis.

Adult↗
PubMedDate not supplied

Inheritance of resistance to zucchini yellow mosaic virus and watermelon mosaic virus in watermelon.

High resistance to zucchini yellow mosaic virus-China strain (ZYMV-CH) and moderate resistance to watermelon mosaic virus (WMV) were found in a selection of PI 595203 (Citrullus lanatus var. lanatus), an Egusi type originally collected in Nigeria. Mixed inoculations showed primarily that these two viruses have no cross-protection. This fact may explain the high frequency of mixed infection often observed in commercial fields. When plants were inoculated with a mixture of the two viruses, the frequency of plants resistant to ZYMV was lower than expected, indicating that WMV infection may reduce the ability of a plant to resist ZYMV. We studied inheritance of resistance to ZYMV-CH and WMV, using crosses between a single-plant selection of PI 595203 and the ZYMV-susceptible watermelon inbreds 9811 and 98R. According to virus ratings of the susceptible parents, the resistant parent, and the F1, F2, and BC1 generations, resistance to ZYMV-CH was conferred by a single recessive gene, for which the symbol zym-CH is suggested. The high tolerance to WMV was controlled by at least two recessive genes.

Citrullus↗
PubMedDate not supplied

Generation of early afterdepolarization in mouse ventricular fibers at long cycle length.

Early afterdepolarization (EAD) was studied in ventricular fibers of mouse heart. EAD could be occasionally induced under long cycle length of superfusion with Tyrode's solution (containing 3.0 or 5.0 mM KCl) at long cycle length. Three types of EAD were found: a second plateau with a prominence, a single triggered burst and a train of triggered bursts. Take-off potential of the first triggered burst or of the prominence varied from -40 to -60 mV. The triggered bursts in the third type often stopped at -35 to -45 mV level forming a very long second plateau before it completely repolarized. Changing abruptly from a long cycle length to a short one lead to a transient EAD induction. It is suggested that EAD in ventricular fiber in mouse heart shared the characteristics of that in atrial fibers, although it was very difficult to induce and was not very reproducible.

Action Potentials↗