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D D Smith

Publications and source records attributed to D D Smith.

At least 109 records · Page 6Linked to original sources
PubMed1984

Production of a macromolecular bone-resorbing factor by the hypercalcemic variant of the walker rat carcinosarcoma.

The Walker rat 256 carcinosarcoma is a spontaneous rat breast tumor which has two unique variants, one of which is always associated with severe hypercalcemia and one which is not associated with hypercalcemia when the tumor is carried im. To determine the factor responsible for hypercalcemia, we established tumor cells derived from both variants in culture and found that the tumor cells from the hypercalcemic variant release an acid-soluble and acid-stable bone-resorbing factor of approximately 25,000 mol wt. Cells from the normocalcemic variant produce no bone-resorbing activity. These data are consistent with the notion that hypercalcemia in this animal model of the humoral hypercalcemia of malignancy is due to a macromolecular bone-resorbing factor which is acid and heat stable and requires disulfide bonds for biological activity.

Animals↗
PubMed1983

Subcellular location of chicken brain glutamine synthetase and comparison with chicken liver mitochondrial glutamine synthetase.

Chicken brain glutamine synthetase has been found to be localized in the cytosolic fraction of this tissue in contrast to its mitochondrial location in chicken liver. Despite this difference in subcellular distribution, the enzyme from brain exhibits the same molecular weight during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, has the same isoelectric point, and is immunochemically cross-reactive. In addition, the immunochemically isolated primary translation products for glutamine synthetase from brain and liver mRNA are the same size. These data suggest that cytosolic brain and mitochondrial liver glutamine synthetase may be derived from the same gene.

Animals↗
PubMed1983

Isolation of a bifunctional domain from the pentafunctional arom enzyme complex of Neurospora crassa.

Limited proteolysis of the arom enzyme complex of Neurospora crassa by trypsin or subtilisin yielded a stable fragment of Mr 68000. This fragment, which was purified by two-dimensional polyacrylamide-gel electrophoresis, was shown by activity staining to contain the shikimate dehydrogenase active site, and by substrate labelling with 3-dehydroquinate and NaB3H4 to contain the 3-dehydroquinase active site. The fragment thus constitutes a bifunctional domain containing the two enzymic activities that are known, from genetic evidence, to be located adjacently at the C-terminal end of the pentafunctional arom polypeptide.

Alcohol Oxidoreductases↗
PubMed1983

Preparation and cross-reactivity of anti-avian glutamine synthetase antibody.

Rabbit antibody to chicken liver mitochondrial glutamine synthetase was purified by immunoaffinity chromatography for analysis of the immunological relatedness of vertebrate glutamine synthetases. The antibody cross-reacted with enzymes from representatives of all five vertebrate classes, indicating a high degree of evolutionary conservatism in the structure of the enzymes. A unique aspect of the immunological similarity of these enzymes is that it exists between cytosolic and mitochondrial enzymes which are, in general, immunologically distinct. The antibody did not cross-react with two insect glutamine synthetases. Compositional difference indices, calculated from the amino acid compositions of glutamine synthetases from several species, gave a mean estimate of over 80% sequence homology for the vertebrate enzymes. The avian mitochondrial enzyme gave a mean 78% homology with the mammalian cytosolic enzyme.

Amino Acid Sequence↗
PubMed1982

Characterization of glutamine synthetase from avian liver mitochondria.

1. Glutamine synthetase has been purified to homogeneity from chicken liver mitochondria. 2. The native enzyme is an octamer composed of identical subunits with monomeric mol. wt of 42,000 dalton. 3. Apparent Kms for NH4+, ATP and glutamate were 0.5, 0.9 and 6 mM, respectively. D-Glutamate and L-alpha-hydroxyglutarate were utilized as substrates with activities approx. 40% those obtained with glutamate. Of several nucleotides tested, none were effective replacements for ATP. 4. Heavy metal ions were inhibitory as were Mn2+, Ca2+ and lanthanide ions. 5. Despite its different subcellular localization and physiological function, avian glutamine synthetase is markedly similar to the weakly-bound microsomal rat liver enzyme with respect to a number of physical and chemical properties.

Amino Acids↗
PubMed1982

Immunization of cats against shedding of Toxoplasma oocysts.

Development of immunity to the shedding of oocysts was examined in 75 kittens that survived infection with the three stages of Toxoplasma gondii. Of 16 kittens fed bradyzoites in cysts, 94% were immune and did not shed oocysts. Of seven injected with tachyzoites 86% were immune. Of 18 fed sporozoites only 11% were immune, but following injection, 54% of 12 were immune. After the administration of either bradyzoites or tachyzoites from nonoocyst-producing strains, only 9% of 22 were immune. Considering all inocula, immunity was present in 93% of kittens that had previously shed oocysts, 25% of those that only develop antibody, and none that had neither shed nor developed an antibody titer. After a second challenge with a different isolate, a similar percentage of immunity was observed. Infection with killed tachyzoites, alone, or together with Freund's complete or incomplete adjuvants was followed by immunity in only one of 24 kittens. Eighty-five percent of 13 kittens were immune, after they had been treated prophylactically with 200 mg/kg monensin, or 60 mg/kg cat sulfadiazine combined with 1 mg/kg cat of pyrimethamine; oocyst shedding had been suppressed in all. It is concluded that cats can be immunized against oocyst shedding by infections where oocysts are produced, or where developmental stages are suppressed by chemoprophylaxis, but not if enteroepithelial stages are absent, as in the oocyst-less strain examined.

Animals↗
PubMed1982

Inhibitory effects of monensin on shedding of Toxoplasma oocysts by cats.

Toxoplasma oocyst shedding by cats was suppressed by 0.02% monensin incorporated in dry cat food. Ten of 12 cats that had not shed oocysts were immune when reinfected with mice chronically infected with Toxoplasma. The medicated food, which was well accepted and tolerated by kittens, could be useful to minimize risks of infection for pregnant women and small children from pet cats defecating in soil close to homes. However, in the presence of stray cats a false sense of security may be engendered.

Animals↗
PubMed1981

Mycobacterial infections in immunosuppressed patients.

A brief account of the laboratory diagnosis of mycobacterial infections in 13 immunosuppressed patients, which were observed between 1967 and 1979 at one group of hospitals is presented. In nine patients, the infection was caused by Mycobacterium tuberculosis; of the "atypical" mycobacteria, M. fortuitum, M. haemophilum, M. kansasii and M. scrofulaceum (serotype Lunning) each caused one infection. These findings suggest that immunosuppressed patients are at risk of tuberculosis, despite the low incidence of the disease in Australia at the present time.

Adult↗
PubMed1980

Distribution of types of Streptococcus pneumoniae isolated in Sydney in 1973--1974 and in 1979.

At The Prince of Wales Hospital, 357 pneumococci isolated in the laboratory from September, 1973, to May, 1974, and 268 pneumococci isolated from June to November, 1979, were serotyped. The pneumococci were isolated from patients and carriers in the hospital and in general practice. The type distribution resembled that described by Hansman regarding 1247 pneumococci isolated from 1965 to 1969. In each of the periods, the same seven predominant types--19, 23, 6, 3, 9, 11 and 15--were isolated in almost exactly the same order of frequency. Of the "epidemic" types--1, 2, 4, 5, 7 and 12--only type 12 was not isolated in the present study. This information may be of value in the choice of components for an appropriate polyvalent pneumococcal vaccine for susceptible children and adults in Australia.

Australia↗
PubMed1980

The pathogenic effects of Mycobacterium haemophilum in immunosuppressed albino mice.

Of 30 prednisolone-treated mice challenged intravenously with Mycobacterium haemophilum, 12 developed skin lesions, primarily on the ears, from which the mycobacterium was isolated. These lesions were not observed in mice challenged with M. haemophilum but not given prednisolone. M. haemophilum infection prolonged the life and reduced the frequency of intercurrent infection with Corynebacterium murium in prednisolone-treated mice.

Animals↗
PubMed1980

Rapid tube CAMP test for identification of Streptococcus agalactiae (Lancefield group B).

A rapid CAMP test for the presumptive identification of Streptococcus agalactiae (Lancefield group B) is described. Sheep erythrocytes, sensitized by staphylococcal beta-lysin and suspended in phosphate-buffered saline, were used to determine the lytic capacity of the neutralized supernatant fluids of 4-h broth cultures of streptococci being tested. A total of 96.2% of 130 group B streptococci gave positive CAMP tests, that is, lysis of the sheep erythrocytes after 10 min of exposure of streptococcal supernatants, whereas none of 381 non-group B streptococci tested produced any lysis. The test described provides presumptive identification of group B streptococci within 4 h and eliminates problems of intermediate reactions so that a positive test is indicative only of CAMP factor production.

Animals↗
PubMed1980

Sarcocystis and related organisms in Australian Wildlife: IV. Studies on Sarcocystis cuniculi in European rabbits (Oryctolagus cuniculus).

The role of the cat (Felis domestica) as a definitive host for Sarcocystis cuniculi of European rabbits (Oryctolagus cuniculus) was confirmed. It was shown that after dosing with sporocysts from cats, rabbits developed sarcocysts and these became infective for cats at not less than 93 days post-infection (p.i.). The earliest infection detected was at 142 days p.i. Infected muscle from an experimental rabbit did not transmit Sarcocystis when fed to other rabbits. Microscopically, sarcocysts in European rabbits (O. cuniculus) were morphologically indistinguishable from those in cottontail rabbits (Sylvilagus floridanus).

Animals↗
PubMed1979

Trichomonas vaginalis infections in Sydney: laboratory diagnosis and prevalence.

The prevalence of trichomoniasis in Sydney was determined by examining 1070 sexually active females in three different practices. Infection rates ranged from 17.8% in a sympatomatic venereal-disease clinic group to 0.5% in non-promiscuous family-planning clinic patients. In each of these categories, the infestation rate, when compared with overseas reports, was lower but no explanation for this difference is apparent. Of the various laboratory methods used to detect Trichomonas vaginalis, the most sensitive was a culture method. The most convenient and reliable microscopy technique was phase-contrast microscopy which detected 80% of those with positive culture results. Stuart's Transport Medium will maintain trichomonad's viability for at least 24 hours and allow vaginal specimens to be reliably transported for examination.

Australia↗