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Biomedical subjects

J M Hyde

Publications and source records attributed to J M Hyde.

11 recordsLinked to original sources
PubMed1995

Olfactory performance during childhood. II. Developing a discrimination task for children.

OBJECTIVES: (1) To create a match-to-sample odorant discrimination task (MODT) for children and adolescents; (2) to assess whether nonolfactory factors affect olfactory performance more on an identification task than on the MODT; (3) to evaluate subjects with olfactory dysfunction; and (4) to create age-appropriate sets of odorants for use in the MODT format to test children of different ages. STUDY DESIGN: We tested 75 normal children, aged 2 to 18 years, and 17 other subjects, aged 7 to 53 years, with known or suspected olfactory dysfunction, with the MODT. We compared the age trends in variability of scores on the MODT with those on an odorant identification task, using a weighted linear regression analysis. RESULTS: The MODT was useful in children aged 5 years and older, but not generally in the 2- to 4-year-old children. There was an appreciable age trend in the variability of the scores on the identification task but not on the MODT. Mean MODT scores for subjects with suspected or known olfactory dysfunction were far below average. Finally, we created four sets of odorants that will likely be sensitive to age-specific changes in olfactory performance. CONCLUSIONS: The MODT appears to be a suitable test instrument to assess olfaction in children aged 5 and older and is less likely to be influenced by nonolfactory factors than an identification task. According to our preliminary results, it is likely that the MODT will allow us to detect olfactory deficits in children of many ages.

Adolescent↗
PubMed1975

Structure and position of a complex chromosomal aberration in bacteriophage P2.

The P2 phage mutation vir56, like the previously studied vir22, is the result of an unequal replacement of a chromosome segment with non-homologous DNA. The end positions of the replacements are essentially the same in the two mutants, whereas the lengths of the replacements are quite different. A third chromosomal aberration, del3, has similar structure and position. These results strengthen the suggestion that the left ends of these three aberrations coincide with the point of exchange in integrative recombination.

Coliphages↗
PubMed1968

Kinetics of viral deoxyribonucleic acid, protein, and infectious particle production and alterations in host macromolecular syntheses in equine abortion (herpes) virus-infected cells.

Infection of exponential-phase suspension cultures of mouse fibroblast cells (L-M) with equine abortion virus (EAV) resulted in inhibition of cell growth and marked alterations in host metabolic processes. The synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid was inhibited within 4 hr after infection and was suppressed by more than 90% by the time of maximal virus replication (14 to 18 hr). The overall rate of protein synthesis, however, was similar in uninfected and virus-producing cells as determined by measurements of net protein and isotope incorporation. The time course of viral DNA and protein synthesis and assembly into mature virus was determined with the inhibitors 5-fluorodeoxyuridine (FUdR) and cycloheximide, respectively. Thus, viral DNA synthesis was essentially completed at 14 hr, and viral protein and infectious virus synthesis was completed at 18 hr. Although the number of plaque-forming units (PFU) produced by FUdR-treated cells (10(3) to 10(4) PFU/ml) was at least 3 logs less than that produced by untreated cells, the yield of physical particles (as determined by electron microscopy) was approximately the same at 30 hr after infection. Besides being relatively non-infective, the particles produced in FUdR-treated cells appeared morphologically incomplete as they contained little or no nucleoid material.

Abortion, Veterinary↗
PubMed1967

Fine structure of quiescent and germinating aeciospores of Cronartium fusiforme.

Aeciospores of the long-cycle heteroecious rust fungus, Cronartium fusiforme, were found to have an extremely thick cell wall with striking spicules protruding from it. The wall was readily degraded by commercial chitinase, but spicules were unaffected. Quiescent spores contained two nuclei with distinct nuclear membranes possessing many pores. Numerous membrane-bounded lipid bodies were found both in wild-type orange and in white mutant aeciospores. An abundance of irregularly ovoid mitochondria was present in quiescent spores. After glutaraldehydeosmium fixation, the surface of the mitochondria appeared to be covered with ribosomes or microtubules in a paracrystalline array, whereas after permanganate fixation only smooth outer mitochondrial membranes were noted. The latter fixative revealed abundant vesicular endoplasmic reticulum in the spore. Spores incubated at 20 C on agar produced one to five distinct germ tubes within 65 to 180 min. These thin-walled tubes exhibited varying degrees of branching, and reached a total hyphal length of 300 to 500 mu prior to rupturing. Emergence of germ tubes took place through a pore in the spore wall and appeared to be mainly a physical flowing of cytoplasm from the spore into the germ tube without division of nuclei or other cell organelles. On completion of germination, the protoplasm of the germ tube contained both nuclei and nearly all of the other spore contents. Mitochondria had smooth outer membranes, were greatly elongated, and possessed distinct longitudinal cristae. A limited amount of rough endoplasmic reticulum was arranged parallel to the germ tube wall. Other organelles seen in germ tubes were lipid bodies, concentric membrane figures, and numerous ribosomes. Lipid bodies appeared smaller and fewer in number than in quiescent spores.

Basidiomycota↗
PubMed1966

Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior.

Randall, Charles C. (University of Mississippi, Jackson), Lanelle G. Gafford, Richard L. Soehner, and James M. Hyde. Physicochemical properties of fowlpox virus deoxyribonucleic acid and its anomalous infectious behavior. J. Bacteriol. 91:95-100. 1966.-Deoxyribonucleic acid (DNA) was extracted from fowlpox virus-infected tissue, purified inclusions, and purified virus by five variations of detergent and phenol methods. Phenol methods gave a poor yield, whereas detergent techniques extracted up to 78% of the DNA. The buoyant density was 1.695 g/ml, and the melting temperature in 7.2 m NaClO(4) was 39 C, both approximately equivalent to a guanine plus cytosine content of 35 moles per cent. Further proof of the double-stranded nature of the DNA was shown by the characteristic behavior toward deoxyribonuclease, formaldehyde, and heat. Infectious DNA was obtained by the various methods described, but this manifestation of biological activity was capricious and for unknown reasons was often not evident. The infectivity could not be related quantitatively to the amount of DNA employed. Furthermore, the infectious nature of fowlpox virus DNA was demonstrable only when the route of infection was the chorioallantoic membrane. In contrast, whole virus infected both membrane and chick skin with equal efficiency.

Biological Assay↗
PubMed1966

Ultrastructure of basidiospores and mycelium of Lenzites saepiaria.

Hyde, James M. (University of Mississippi Medical School, Jackson), and Charles H. Walkinshaw. Ultrastructure of basidiospores and mycelium of Lenzites saepiaria. J. Bacteriol. 92:1218-1227. 1966.-Ungerminated and germinated basidiospores and 2-day-old mycelial cultures of Lenzites saepiaria were similar in their fine structure. Fixation with glutaraldehyde, followed by osmium tetroxide, was far superior to permanganate. Cell organelles were seen in cytoplasm of spores and hyphae, and clamp connections were abundant in hyphal elements. Numerous lomasomes, vesicular bodies, and complex concentric membranes occurred in the cytoplasm and were often associated with the cell membrane or the dolipore membrane (parenthesome) of the septum. Endoplasmic reticulum was not found, but numerous ribosomes were seen; polyribosome groupings were frequently noted. The nucleus was bounded by a double membrane which contained few pores. Germinating spores exhibited one or more large osmiophilic bodies in association with a vacuole and membranous elements. Other than possessing a thin wall, the emerging germ tube was similar in structure to the parent spore.

Basidiomycota↗