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Biomedical subjects

W B Neaves

Publications and source records attributed to W B Neaves.

66 records · Page 4Linked to original sources
PubMed1969

Gene dosage at the lactate dehydrogenase b locus in triploid and diploid teiid lizards.

Triploid parthenogenetic lizards which are heterozygous at the lactate dehydrogenase b locus show approximately two doses of the b allele and approximately one dose of the b' allele. This finding agrees with the triploid karyotype composed of two haploid complements of chromosomes indistinguishable from those of species carrying the b allele and one complement indistinguishable from that of the species which carries the b' allele. Densitometry of electrophoretic patterns of lactate dehydrogenase from heart muscle and from kidney indicates approximately equal expression of each of the b alleles in the triploid lizards. Heterozygouis diploid lizards from the same parthenogenetic species, in agreement with their karyotype, show equal doses of b and b' alleles.

Alleles↗
PubMed1968

Lactate dehydrogenase isozymes in parthenogenetic teiid lizards (Cnemidophorus).

Heterozygosity occurs at the lactate dehydrogenase b-locus in two diploid parthenogenetic species of Cnemidophorus. Each such species produces two different B subunits, one of which is also found in two sexual species and in two triploid parthenogenetic species; the other occurs also in a third sexual species. Interspecific hybridization between sexual species carrying different b-alleles and producing different B subunits may be responsible for the heterozygosity at the lactate dehydrogenase b-locus in diploid parthenogenetic Cnemidophours.

Animals↗
PubMedDate not supplied

Age-related variation in seminiferous tubules in men. A stereologic evaluation.

Tubular boundary tissue and seminiferous epithelia were evaluated stereologically in testes from 28 men aged 20 to 48 years and 28 men aged 50 to 90 years. Testes obtained at autopsy within 15 hours of death were perfused with glutaraldehyde, embedded in Epon (Ladd Research Industries, Inc., Burlington, VT), sectioned at 0.5 micron, and stained with toluidine blue. Volume densities (percentage of the testicular parenchyma) of various parameters determined by point counting and diameter measurements were used to calculate total volumes, length of tubules, and number of cells. Electron microscopy was used to determine the volume density of myoid cells in the boundary tissue. Significant (P less than 0.01) age-related reductions occurred in paired testicular weights, paired parenchymal weights, total volume of seminiferous tubules and of seminiferous epithelium, and length of tubules. The volume density and thickness of boundary tissue increased (P less than 0.01) with age. The volume of boundary tissue per man and the volume density of myoid cells in the boundary tissue did not vary with age. Although the number of myoid cells per man tended to be lower in the older group, the number of myoid cells per cross section of seminiferous tubule was increased (P less than 0.01) in older men. The age-related thickening of the boundary tissue was not due to an increase in boundary tissue but resulted from a reduction in the length of the seminiferous tubules.

Adult↗
PubMedDate not supplied

Regional and subcellular localization of luteinizing hormone releasing hormone in the adult human brain.

The localization of luteinizing hormone releasing hormone (LHRH) in the post mortem adult human brain was investigated. LHRH was highly concentrated in medial basal hypothalamic tissue (1.14 ng/mg protein); lower levels of LHRH were present in tissue from the optic chiasm (0.05 ng/mg protein) and mammillary bodies (0.07 ng/mg protein). The concentrations of LHRH in hypothalamic tissue of men and women were similar. LHRH was undetectable (< 0.001 ng/mg protein) in the frontal cerebral cortex and cerebellum. When homogenates of the medial basal hypothalamus were fractionated on continuous or discontinuous sucrose density gradients, LHRH was found to be associated with subcellular particles. Upon examination by transmission electron microscopy, we found that these subcellular particles resembled isolated neuron terminals, i.e., synaptosomes. Low to undetectable amounts of LHRH were found in the cytosol or the myelin + microsome fraction of the gradients. The results of these studies are supportive of the view that LHRH is highly concentrated in neuron terminals of the adult human brain and may, therefore, be a central neurotransmitter or neuromodulator in the human.

Adolescent↗