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Biomedical subjects

D Nash

Publications and source records attributed to D Nash.

At least 73 records · Page 4Linked to original sources
PubMed1985

Three purine auxotrophic loci on the second chromosome of Drosophila melanogaster.

Mutations at three second-chromosomal loci of Drosophila melanogaster have been isolated, mapped, and shown to be purine nucleoside auxotrophs. Two of the loci, adenosine2 and adenosine3, located at map positions 18.4 and 20, respectively, produce mutations which are supplementable with adenine, adenosine, and inosine. Guanosine supplements mutations at the burgundy locus (55.7); this locus was described previously through a pteridine eye-color defect but identified as an auxotrophic locus after the isolation of a new allele, burgua2-1. The mutation ade2-1 also has defective pteridine metabolism.

Adenosine↗
PubMed1983

Properties of substantially chlorophyll-free pea leaf mitochondria prepared by sucrose density gradient separation.

Mitochondria isolated from pea leaves (Pisum sativum L. var Massey Gem) and purified on a linear sucrose density gradient were substantially free of contamination by Chl and peroxisomes. They showed high respiratory rates and good respiratory control and ADP/O ratios. Malate, glutamate, succinate, glycine, pyruvate, alpha-ketoglutarate, NADH, and NADPH were oxidized but little or no oxidation of citrate, isocitrate, or proline was detected. The oxidation of NADPH by the purified mitochondria did not occur via a transhydrogenase or phosphatase converting it to NADH. NADPH oxidation had an absolute requirement for added Ca(2+), whereas NADH oxidation proceeded in its absence. In addition, oxidation of the two substrates showed different sensitivities to chelators and sulfhydryl reagents, and faster rates of O(2) uptake were observed with both substrates than with either alone. This indicates that the NADPH dehydrogenase is distinct from the exogenous NADH dehydrogenase.

Journal Article↗
PubMed1981

Increased serum and urinary calcitonin levels in patients with pulmonary disease.

Serum and urinary calcitonin levels were measured in patients with acute and chronic inflammatory diseases of the lung. Using both carboxyl terminal and midportion antisera, the incidence of increased immunoreactive values of this hormone was 68 percent for patients with emphysema, 59 percent for tuberculosis, and 89 percent for acute bacterial pneumonitis. In order to determine the source of the high levels of calcitonin, immunoperoxidase stains were made of sections of human lung; the hormone was found within the bronchial Kultschitzky cell (K cell). This suggests a specific endocrine role for the K cell, and may explain not only the high calcitonin levels in patients with inflammatory lung disease, but also the high levels associated with both carcinoid tumor and small cell carcinoma, which may originate from K cells. It is apparent that moderately high levels of calcitonin in a patient with pulmonary disease cannot always be associated with tumor.

Adult↗
PubMed1980

A comparison of treatment modalities in carcinoma of the maxillary antrum.

Sixty-two patients with carcinoma of the maxillary antrum are observed to define symptoms, physical findings, and radiologic findings suggestive of a poor prognosis. Using these poor prognostic indicators, the cases are retrospectively analyzed according to the various treatment modalities that were used. It is concluded from the accumulated data that raesection of the orbital contents can be avoided in selected patients with T3 and T4 carcinoma of the paranasal sinuses.

Adenocarcinoma↗
PubMed1979

Cytogenetic localisation of the purine 1 and guanosine 1 loci of Drosophila melanogaster; the purine 1 locus specifies a vital function.

Three auxotrophic mutants at two loci (pur 1 and gua 1) apparently involved in purine metabolism were mapped cytologically to region 9E1-9E3 on the X-chromosome of Drosophila. Because mutants of pur 1 behaved as semi-lethals against deficiencies even on permissive medium, it appears that the pur 1 locus is vital to the fly and its auxotrophic mutants are hypomorphs.

Animals↗
PubMed1979

The value of hysterosalpingography prior to donor artificial insemination.

The value of hysterosalpingography as a tool in the pretreatment evaluation of candidates for donor artificial insemination has been retrospectively evaluated. In 89 consecutive artificial inseminations by donor candidates, hysterosalpingograms were evaluated for genital tract abnormalities. In only four of these studies was there a failure of dye to spill into the peritoneal cavity. The low incidence of significantly abnormal hysterosalpingographic studies, and the failure of these studies to correlate with pregnancy outcome, strongly argues against the use of hysterosalpingography in the preliminary evaluation of the patient considered for donor artificial insemination.

Adult↗
PubMed1979

A thermographic study of heat distribution during ultra-speed cavity preparation.

Thermography was employed to determine the pattern of heat generation, distribution and dissipation during ultra-high speed cavity preparation. Results indicate an increase in intrapulpal temperature during cutting procedures. No significant differences in the cooling effectiveness between air-water spray and air alone were found. Thermography appears to be an effective research tool for determining thermal changes.

Air↗
PubMed1976

Nucleoside auxotrophy in Drosophila: an autosomal locus yielding mutants supplementable by purine and pyrimidine ribonucleosides.

Two allelic auxotrophic mutants at a locus close to the bw locus (2-104.5) of Drosophila melanogaster are described. The mutants respond to dietary ribonucleosides (uridine, cytidine, adenosine, guanosine and inosine) but less well to bases or pyrimidine precursors. This phenotype is unique to these mutants. We suggest that the mutants are defective in phosphoribosyl pyrophosphate biosynthesis.

Adenosine↗
PubMed1976

Maternally influenced embryonic lethality: allele specific genetic rescue at a female fertility locus in Drosophila melanogaster.

A new locus, mel(1)R1, with a maternal effect on embryonic development, has been mapped at about 0.5 on the X chromosome of Drosophila melanogaster and localized cytologically between bands 2D6 and 3A1. Genotypically mutant embryos die if produced by homozygous mutant females but survive if produced by heterozygous females. Two mutant alleles have been isolated. One of these is genetically rescuable: when homozygous mutant females are mated to mutant males, all the embryos die, but when these females are mated to normal males, female offspring are produced. The other allele is not rescuable. Genetic rescue is dominant at this locus since females heterozygous for the two mutant alleles produce female offspring in crosses to normal males.

Alleles↗
PubMed1974

Sex-linked auxotrophic and putative auxotrophic mutants of Drosophila melanogaster.

Thirty-two mutants with improved growth response on a yeast-sucrose compared with a defined medium have been characterized with respect to ribonucleoside supplementability. Twenty mutants respond to either pyrimidine ribonucleoside. Four mutants respond to one or both purine ribonucleosides. Eight mutants ("putative" auxotrophs) do not respond to dietary RNA supplementation. Mapping and complementation studies suggest that eleven loci are represented: one, rudimentary, probably accounts for all pyrimidine requirers; there are three purine loci and seven at which the putative auxotrophs are found.

Animals↗