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Biomedical subjects

D F Smith

Publications and source records attributed to D F Smith.

At least 217 records · Page 12Linked to original sources
PubMed1989

Binding of heat shock proteins to the avian progesterone receptor.

The protein composition of the avian progesterone receptor was analyzed by immune isolation of receptor complexes and gel electrophoresis of the isolated proteins. Nonactivated cytosol receptor was isolated in association with the 90-kilodalton (kDa) heat shock protein, hsp90, as has been described previously. A 70-kDa protein was also observed and was shown by Western immunoblotting to react with an antibody specific to the 70-kDa heat shock protein. Thus, two progesterone receptor-associated proteins are identical, or closely related, to heat shock proteins. When the two progesterone receptor species, A and B, were isolated separately in the absence of hormone, both were obtained in association with hsp90 and the 70-kDa protein. However, activated receptor isolated from oviduct nuclear extracts was associated with the 70-kDa protein, but not with hsp90. A hormone-dependent dissociation of hsp90 from the cytosolic form of the receptor complex was observed within the first hour of in vivo progesterone treatment, which could explain the lack of hsp90 in nuclear receptor complexes. In a cell-free system, hsp90 binding to receptor was stabilized by molybdate but disrupted by high salt. These treatments, however, did not alter the binding of the 70-kDa protein to receptor. Association of the 70-kDa protein with the receptor could be disrupted by the addition of ATP at elevated temperatures (23 degrees C). The receptor-associated 70-kDa protein is an ATP-binding protein, as demonstrated by its affinity labeling with azido[32P]ATP. These results indicate that the two receptor-associated proteins interact with the progesterone receptor by different mechanisms and that they are likely to affect the structure or function of the receptor in different ways.

Adenosine Triphosphate↗
PubMed1989

Hydroxyapatite associated disease in an elderly female: differentiation from aseptic necrosis.

The crystal arthropathies caused by monosodium urate and calcium pyrophosphate dihydrate are commonly recognised, but the destructive arthropathy associated with the deposition of calcium hydroxy-apatite is less well known in general clinical practice. We describe a case with many of the classical features of hydroxy-apatite associated disease and discuss the features differentiating the condition from aseptic necrosis.

Aged↗
PubMed1989

99Tcm-HMPAO single photon emission computed tomography in partial epilepsy: a preliminary report.

In the pre-operative assessment of patients being considered for temporal lobe surgery, accurate lateralization and localization of the epileptic focus is mandatory. Surface electroencephalography (EEG) can be misleading and confirmatory evidence, preferably non-invasive, of the site of the epileptic focus is valuable. Sixteen patients with partial epilepsy, six of whom were considered to be good surgical candidates, had technetium-99m hexamethylpropylene amine oxime (99Tcm-HMPAO) scanning. In those patients with poor epileptic control and a well localized EEG focus, there was a correlation between EEG and HMPAO scan abnormalities, whilst in all patients where no correlation existed, the HMPAO scan was normal. We conclude that 99Tcm-HMPAO single photon emission computed tomography may be a useful non-invasive, adjunctive investigation in the preoperative assessment of patients with partial epilepsy.

Adolescent↗
PubMed1989

Comparison of heparin and 0.9% sodium chloride injection in the maintenance of indwelling intermittent i.v. devices.

Heparin sodium 10 units/mL was compared with 0.9% sodium chloride injection as a flush solution for indwelling intermittent i.v. devices, or i.v. locks (IVLs), in a prospective, randomized, double-blind study. The heparin and 0.9% sodium chloride injections were prepared in the pharmacy using aseptic technique. Most of the IVLs were inserted by an i.v. therapy team member. Each patient's IVL site was evaluated for phlebitis and patency by one of three study nurses, and when a catheter was removed, its contents were flushed so that clots or fibrin strands could be detected. Nurses also collected information regarding disease states, surgical procedures, medications administered, and how long each site lasted. A total of 173 sites were studied in 76 patients in the heparin group, and 131 sites were studied in 71 patients in the sodium chloride group. The groups were well matched, except that the sodium chloride group received more vancomycin and dextrose-containing i.v. solutions, while the heparin group received more penicillins. There was no significant difference in the incidence of phlebitis or lost patency between the groups. When locks through which vancomycin, penicillins, and dextrose-containing i.v. solutions were administered were excluded, there was still no significant difference between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Vascular anatomy of the equine small colon.

The vasculature of 22 small colons from dead adult ponies was perfused with latex or barium sulphate solution. The vascular anatomy was studied by use of dissection and alkali digestion of the latex specimens and microangiography of the barium sulphate-perfused specimens. The small colon is supplied by the caudal mesenteric artery. The left colic artery arises from the caudal mesenteric artery, which then becomes the cranial rectal artery. Branches from the left colic and cranial rectal arteries form anastomosing arcades that become narrower distally along the length of the small colon. From these arcades arise terminal arteries, which enter the small colon wall and give rise to a subserosal, an intermuscular, and a large submucosal plexus, with frequent anastomoses between them. The venous drainage closely parallels the arterial supply, except near to its origin from the portal vein, when the left colic vein and caudal mesenteric vein are separate from the corresponding arteries.

Animals↗
PubMed1988

A novel sialylhexasaccharide from human milk: purification by affinity chromatography on immobilized wheat germ agglutinin.

A sialylhexasaccharide fraction (S-5) of human milk was obtained as described by A. Kobata and V. Ginsburg [(1972) Arch. Biochem. Biophys. 150, 273-281] and labeled by reduction with NaB[3H]4. When subjected to affinity chromatography on immobilized wheat germ agglutinin (WGA), a single component representing 60% of the S-5 fraction was retarded by the column. The asialo derivative of the WGA-retarded oligosaccharide had a higher affinity for the WGA column than the native sialyloligosaccharide. The neutral hexaose was identified as lacto-N-neohexaose by sequential exoglycosidase digestions in combination with gel filtration analyses of digestion products. Enzymatic removal of the nonsialylated branch of the intact sialyloligosaccharide by jack bean beta-galactosidase and beta-N-acetylhexosaminidase resulted in a single sialyl[3H]tetraose which was identified as sialyltetrasaccharide c (NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4GlcO[3H]) by cochromatography with authentic standard and specific antibody binding. Independent evidence for the structure of the sialylhexasaccharide was obtained by 500-MHz1H NMR spectroscopy of the WGA-purified oligosaccharide before and after neuraminidase digestion. The structural data are consistent with the following, previously undescribed, sialylhexaose in human milk: (formula; see text).

Chromatography, Affinity↗
PubMed1988

Intramural hematoma in the jejunum of a mare.

An intramural hematoma involving a 40-cm segment of the distal portion of the jejunum caused intestinal obstruction and colic in a mature mare. The involved intestine was resected, and an end-to-end anastomosis was performed. The mare recovered completely, but 4 years later had colic caused by incarceration and volvulus of the distal portion of the jejunum, involving fibrous abdominal adhesions. The cause of hematoma was not identified; however, rupture of an intramural vessel after migration of Strongylus vulgaris larvae was considered a possibility because of the histologic observation of an intense eosinophilic infiltrate in the region. Vascular rupture caused by blunt abdominal trauma was considered unlikely. Previous descriptions of intramural hematoma in the horse have been confined to the small colon.

Animals↗
PubMed1988

Jejunojejunal intussusception associated with a transmural adenocarcinoma in an aged cow.

After 3 days of intestinal obstruction, a proximal jejunojejunal intussusception was resected during surgery in an adult Holstein cow. A transmural adenocarcinoma was found at the proximal margin of the intussusception. The cow recovered well from surgery and produced milk and embryos to expectation. During the seventh month after surgery, the cow developed pneumonia and, therefore, was euthanatized. Disseminated abdominal and thoracic neoplasia was observed at necropsy.

Adenocarcinoma↗
PubMed1988

Hormone-dependent processing of the avian progesterone receptor.

Avian progesterone receptor exists as two forms, A and B, with molecular weights of 79,000 and 110,000 daltons, respectively. The origin and significance of these two forms is an area of active investigation and debate. Monoclonal antibodies produced against these two forms were used to examine receptor stability in cytosol and changes in the receptor forms induced by hormone binding. The lability of hormone binding at elevated temperatures is well documented. Analysis by Western blotting showed the receptor was stable in freshly prepared oviduct cytosol for 2 hr at 37 degrees C, while hormone binding was lost within 30 min. However, loss of receptor through degradation was seen when cytosol was prepared from frozen tissue or when homogenization was excessive. Progesterone was injected into diethylstilbestrol-stimulated chicks to examine, in vivo, effects of hormone treatment on receptor forms in the cytosol and nuclear fractions. Progesterone treatment caused a time- and dose-dependent conversion of the A receptor to a form (A') with a slower electrophoretic mobility. The cytosolic progesterone receptor was divided equally between the B and A forms, while the nuclear receptor was predominantly A'. The amount of nuclear receptor was consistently less than cytosolic receptor. Receptor phosphorylation was analyzed by incubating tissue minces with [32P]orthophosphate with or without progesterone followed by immune isolation of receptor forms. Progesterone treatment caused a time-dependent increase in cytosol receptor phosphorylation which was evident after 5 min of treatment. This phosphorylation was observed with both the A and B receptor forms. The results indicate that receptor phosphorylation is a very early event during progesterone action.

Animals↗
PubMed1988

Lithium attenuates clonidine-induced hypoactivity: further studies in inbred mouse strains.

Four strains of mice (C57, BALB, DBA, C3H) were used to determine whether genetic factors influence the effects of lithium on hypoactivity induced by a low dose of the alpha 2-adrenoceptor agonist clonidine (0.2 mg/kg). Lithium was administered in the diet for 3-4 weeks at a dosage that produced average serum lithium levels of 0.58-0.66 mmol/l. Locomotor activity was reduced by either clonidine or by lithium given alone. When combined, however, lithium attenuated the activity-suppressant effects of clonidine, and that action was influenced by genetic factors. The findings suggest that genetic differences in alpha 2-adrenoceptors play a role in behavioural effects of lithium.

Animals↗
PubMed1988

Purification of Forssman and human blood group A glycolipids by affinity chromatography on immobilized Helix pomatia lectin.

A method for the affinity purification of intact glycolipids having nonreducing terminal alpha 1-3 linked N-acetylgalatosamine residues has been developed. This technique relies on the retention of the carbohydrate-binding specificity of immobilized Helix pomatia lectin in aqueous solutions of tetrahydrofuran. Both Forssman glycolipid and a mouse blood group A-active hexaosylceramide were bound by columns of the lectin equilibrated in a solvent containing 95% tetrahydrofuran and 5% water. After application of a step gradient of increasing water content up to 50%, the specifically bound glycolipids were eluted in solvent containing N-acetylgalactosamine. The Forssman and A-active glycolipids were similarly purified in a single chromatographic step from total lipid extracts of sheep and human type A erythrocyte stroma, respectively. Nonspecifically bound lipids and glycolipids were eluted from this column by simply increasing the water content of the eluting buffer. The extension of this method to other carbohydrate-binding proteins including lectins and monoclonal antibodies may provide a rapid purification of glycolipids based on their carbohydrate structures.

Animals↗
PubMed1988

Separation of oligosaccharides containing terminal alpha-linked galactose residues by affinity chromatography on Griffonia simplicifolia I bound to concanavalin A-sepharose.

The seeds of Griffonia simplicifolia contain a family of five isolectins (GS-I) (L. A. Murphy and I. J. Goldstein (1977) J. Biol. Chem. 252, 4739-4742) that bind with high affinity to glycoconjugates containing terminal nonreducing alpha-linked galactose residues. Here, we report that GS-I itself is bound via its high mannose-type, Asn-linked sugar chains to immobilized concanavalin A (Con A-Sepharose). The GS-I in the GS-I-Con A-Sepharose complex retains its ability to bind glycoconjugates containing terminal alpha-linked galactose residues. This convenient method to immobilize GS-I is rapid and quantitative. We have exploited this affinity system to separate oligosaccharides based on their number of terminal alpha-linked D-galactose residues.

Animals↗