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D J Morris

Publications and source records attributed to D J Morris.

At least 163 records · Page 9Linked to original sources
PubMed1989

18-Substituted steroids. Part 15. 6 beta-Hydroxylation of aldosterone by liver.

6 beta-Hydroxyaldosterone and 6 beta-hydroxy-17-isoaldosterone, characterized by high-field NMR studies, are among the major polar metabolites formed from aldosterone by incubation with rat liver slices or microsomal fraction. It is uncertain at present whether the 17-iso product results from an enzymatic or a chemical inversion of configuration. Periodate degradation of the 6 beta-hydroxyaldosterone gave 6 beta-hydroxyaldosterone gamma-lactone, identical with a synthetic sample.

Aldosterone↗
PubMed1989

Inhibitory effects of various anticoagulants on the infectivity of human cytomegalovirus.

We assessed the extent to which the anticoagulants heparin, sodium citrate, Alsever's solution and ethylene diamine tetra-acetic acid (EDTA) (at standard low concentration or at high concentration as attained when only a small blood volume was collected into anticoagulant) inhibited the infectivity of human cytomegalovirus (HCMV). All four anticoagulants had minimal effects on cell-associated virus, but heparin at either low or high concentration and EDTA at high concentration reduced the titre of cell-free virus by 10-100 fold. The large inhibitory effects of heparin and EDTA on cell-free virus indicated that sodium citrate or Alsever's solution were preferable as anticoagulants when blood was collected for assay of CMV viraemia by virus isolation.

Anticoagulants↗
PubMed1989

Detection of cytomegalovirus DNA using probes labelled with digoxigenin.

Cloned HindIII restriction fragments of cytomegalovirus (CMV) DNA (strain AD169) were labelled with biotin, digoxigenin or 32P and used as probes to detect CMV DNA. Probes biotinylated by nick translation, random hexanucleotide priming (RHP) or "photobiotin" were able to detect 10-50 pg of homologous DNA. Probes labelled with digoxigenin or 32P by RHP detected 0.1 pg of homologous DNA, and 1-10 CMV-infected fibroblasts. Comparison of digoxigenin- and 32P-labelled probes in a DNA hybridisation assay on 186 urine specimens demonstrated that these probes were of similar sensitivity, detecting CMV DNA in 40 and 41 specimens, respectively. Positive results were obtained using this hybridisation assay with 11 of 14 specimens (79%) yielding CMV by virus isolation, and with 35 other specimens obtained from patients with laboratory evidence of CMV infection or symptoms compatible with CMV disease. Thus digoxigenin-labelled probes may provide an assay that can detect CMV DNA in specimens yielding a negative result by virus isolation.

Biotin↗
PubMed1989

Metabolism of aldosterone in the colostomized duck (Anas platyrhynchos): partial characterization of urinary metabolites.

1. Chronically colostomized ducks were injected with [4-14C]-aldosterone to study the metabolism of aldosterone and the pattern of metabolite excretion via the kidney. 2. Nearly half of the injected dose was excreted as radiometabolites during the first 24 hr; the largest amounts being excreted during the first 3 hr after injection. 3. Ion-exchange chromatography showed that monosulfate, disulfate, glucuronide, acidic, and neutral metabolites were excreted during each collection period, and that their relative proportions changed with time after injection of [4-14C]-aldosterone. 4. HPLC analysis of the neutral radiometabolites revealed 15 major peaks with retention times corresponding to both polar and reduced derivatives of aldosterone. 5. Only small quantities of unaltered labelled aldosterone were excreted. 6. Treatment of the birds with SKF 525-A caused a decrease in the total quantity of radiometabolite excreted and a change in the proportions of neutral and acidic metabolites in the cloacal fluid. 7. The decreases that occurred in the absolute amounts of some of the polar metabolites excreted by the birds treated with SKF-525A suggests that they may be hydroxylated and at least part of the aldosterone metabolizing system in the duck is cytochrome P450 dependent.

Aldosterone↗
PubMed1989

Laboratory diagnosis and clinical significance of rubella in children with cancer.

Virus-specific antibody responses were studied in 12 children with cancer in whom rubella was diagnosed by seroconversion or a rising titre (greater than or equal to fourfold) of haemagglutination inhibiting (HI) antibody. Our results confirmed the difficulties of making a diagnosis of rubella infection in immunocompromised children using criteria for interpreting antibody assays established in immunocompetent patients. Specific IgM antibody persisted for more than 2 months in 7 of 10 children with probable primary rubella, 3 of whom had high concentrations of such antibody 6, 7 and 11 months after the rash. Radial haemolysis and specific IgG1 and IgG3 antibody responses were low in 4, 2, and 4 patients, respectively. One child apparently had a rubella reinfection and, in another, rubella antibody passively acquired from blood transfusions was probably responsible for the HI seroconversion. Nonetheless, the benign clinical course of rubella in immunocompromised children was confirmed.

Antibodies, Viral↗
PubMed1989

Effect of carbenoxolone on glucocorticoid metabolism and Na transport in toad bladder.

In humans, diminished 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) enzyme activity has been associated with sodium retention and hypertension. These studies show that the toad bladder, another target tissue epithelium displaying steroid-induced sodium transport, possesses the enzyme 11 beta-OHSD. The toad urinary bladder rapidly transformed corticosterone (3 x 10(-8) M) (50% by 10 min and 90% by 180 min) with 11-dehydrocorticosterone being the major metabolite. The 11-dehydrocorticosterone produced reached an apparent plateau when the tissue incubations were repeated with higher concentrations of corticosterone (10(-7) and 10(-6) M). Carbenoxolone sodium (2.5 x 10(-5) M), a water soluble derivative of glycyrrhetinic acid, markedly inhibited the metabolism of corticosterone (3 x 10(-8) M) to 11-dehydrocorticosterone similar to previous observations in the mammalian kidney. Carbenoxolone sodium (2.5 x 10(-5) M) did not significantly affect short-circuit current (SCC) in toad bladders when added to either the serosal or mucosal bath. However, when carbenoxolone sodium was added to the mucosal bath and 60 min later corticosterone 10(-6) M was placed in the serosal bath, bladders generated a SCC 2.07 +/- 0.17 (mean +/- SE) times above base line at 360 min compared with 1.48 +/- 0.11 in bladders exposed to corticosterone alone (P less than 0.02). In parallel experiments, carbenoxolone sodium in the mucosal bath enhanced the rise in SCC induced by cortisol 10(-6) M; 1.66 +/- 0.16 times above base line at 360 min compared with 1.07 +/- 0.14 with cortisol alone (P less than 0.02). We conclude that the toad bladder contains 11 beta-OHSD and inhibition of this enzyme with carbenoxolone sodium is associated with amplification of glucocorticoid-induced transepithelial sodium transport in this tissue. However, since the quantity of 11-dehydro-product produced appears to be limited, other factors in addition to inhibition of 11 beta-OHSD may play a role in this amplification of sodium transport.

Animals↗
PubMed1989

The antinatriuretic and kaliuretic effects of the glucocorticoids corticosterone and cortisol following pretreatment with carbenoxolone sodium (a liquorice derivative) in the adrenalectomized rat.

Carbenoxolone Sodium (CS), a chemical derivative of liquorice is known to be associated with hypertension, increased sodium retention and hypokalemia. The present studies describe the effects of CS on the renal actions of the glucocorticoids Corticosterone (B) and Cortisol (F) on sodium and potassium in adrenalectomized male rats. B (50, 100 and 500 micrograms/rat) and F (1 mg/rat) were found to possess no intrinsic antinatriuretic activity which is represented by a decrease in the Na+ to creatinine ratio; while only B (500 micrograms/rat) demonstrated kaliuretic effects as indicated by an increase in K+ to creatinine ratios. B and F showed very significant antinatriuretic and kaliuretic properties following pretreatment with CS (2.5 mg/rat). CS alone was not found to be antinatriuretic at this dosage. Further experiments demonstrated that lower dosages of CS (500 and 1,000 micrograms/rat) also cause B to exhibit Na+ retaining and K+ excreting properties. Thus, we have demonstrated that pretreatment with CS can confer mineralocorticoid-like activity upon the glucocorticoids B and F.

Adrenalectomy↗
PubMed1988

Detection of cytomegalovirus by dot-blot DNA hybridization using probes labelled with 32P by nick translation or random hexanucleotide priming.

A DNA hybridization assay for the detection of human cytomegalovirus (HCMV) DNA was developed using random hexanucleotide-primed 32P-labelled Hind III restriction fragments of HCMV DNA as probes, and compared with a DNA hybridization assay using probes labelled with 32P by nick translation. Nick-translated probes were shown to be able to detect between 1 and 10 pg of homologous DNA or the DNA of 10-50 HCMV-infected fibroblasts. Random hexanucleotide-primed DNA probes lowered these detection limits to 0.1-0.5 pg of homologous DNA or one to five HCMV-infected fibroblasts. An increase in the autoradiographic exposure time from 18 h to 4 days increased the level of detection for homologous DNA or HCMV-infected fibroblast DNA by approximately five-fold. Preliminary screening of 35 urine samples by DNA hybridization using a random hexanucleotide-primed probe correctly identified three samples positive by virus isolation in tissue culture or immediate-early nuclear antigen detection and 29 of 32 samples negative by tissue culture.

Autoradiography↗
PubMed1988

Changes in 5 alpha- and 5 beta-reductase pathways of aldosterone metabolism by dietary sodium.

The effects of dietary Na+ on 5 alpha- and 5 beta-reductase pathways of aldosterone metabolism in the liver were studied in male rats maintained on low, control, and high Na+ diets. A high Na+ diet caused significant increases in the synthesis of 5 beta-reduced metabolites, primarily 3 alpha, 5 beta-tetrahydroaldosterone; whereas a low Na+ diet stimulated the 5 alpha-reductase pathway causing increases in the synthesis of 5 alpha-dihydroaldosterone and 3 beta 5 alpha-tetrahydroaldosterone, as well as certain polar, hydroxylated metabolites of aldosterone. These studies demonstrate that dietary Na+, a known regulator of aldosterone synthesis, may also regulate enzymes involved in aldosterone metabolism in peripheral tissues.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1988

Rhinocerebral mucormycosis in an anephric patient.

We have described a fatal case of rhinocerebral mucormycosis in a stable anephric patient who was not diabetic and was not receiving immunosuppressive therapy. In a literature search from 1966 to the present, ours is only the second case of a stable dialysis patient reported with this illness, and it is the only reported fatality.

Adult↗
PubMed1988

Time-dependent aldosterone metabolism in toad urinary bladder.

Aldosterone (Aldo) metabolism was examined in the toad bladder. Bladders were incubated with [3H]aldosterone (10(-7) M) for 5 h, 1 h, or 10 min. Tissues were analyzed for metabolites using high-pressure liquid chromatography (HPLC). In separate experiments, Na+ transport was assessed by the short-circuit current (SCC) technique. Following a 5-h tissue incubation, about 25% of the [3H]-aldosterone was converted into metabolites including a polar monosulfate metabolite, 20 beta-dihydroaldo (20 beta-DHAldo), small quantities of 5 beta-reduced products, and a variety of 5 alpha-reduced Aldo products including 5 alpha-DHAldo, 3 alpha,5 alpha-tetrahydroaldo (3 alpha,5 alpha-THAldo), and 3 beta,5 alpha-THAldo. Tissues metabolized approximately 10% of the labeled hormone into the same compounds by 1 h. Measurable quantities of these metabolites were also synthesized by bladders exposed to Aldo for only 10 min and then incubated in buffer for an additional 50 min without Aldo. Bladders pretreated with the spironolactone, K+-canrenoate (3.5 X 10(-4) M), and stimulated with Aldo (10(-7) M) generated a peak SCC 44 +/- 6% of that observed in matched pairs stimulated with Aldo (P less than 0.001; n = 6). K+-canrenoate also markedly diminished [3H]aldosterone metabolism at both 5 and 1 h. Thus, metabolic transformation of Aldo begins prior to hormone-induced increases in Na+ transport. Both the generation of certain metabolites (e.g., 5 alpha-reductase pathway products) and the increase in Na+ transport can be selectively inhibited by K+-canrenoate.

Aldosterone↗
PubMed1987

Enzymatic synthesis of 3H-labeled Ring-A reduced metabolites of aldosterone and their separation by high pressure liquid chromatography.

Specific methods are described for the enzymatic synthesis of each of the six possible 3H-labeled Ring-A reduced metabolites of aldosterone (5 alpha- and 5 beta-DHAldo; 3 alpha,5 alpha-THAldo; 3 beta,5 alpha-THAldo; 3 alpha,5 beta-THAldo; and 3 beta,5 beta-THAldo; see footnote 1 for full names). Use of heated jacketed columns (C8-reverse phase) and two HPLC solvent systems, with isocratic aqueous methanol or acetonitrile, respectively, have been developed which resolve all six Ring-A reduced metabolites of aldosterone. The relative retention times and elution order of each reduced metabolite are different with each solvent system and hence help confirm the identities of Ring-A reduced metabolites made in vivo from physiological quantities of [3H]aldosterone. The use of an on-line beta-radioactivity detector (Berthold LB-504) enhanced the sensitivity of detection and markedly improved the resolution of these metabolites, compared with that obtained by off-line scintillation counting. Thus, the use of increased temperature with these two solvent systems, together with an on-line radioactivity detector, provide a useful and efficient analytical tool for the separation and identification of each reduced metabolite of aldosterone.

Aldosterone↗
PubMed1987

Comparison of dot-blot DNA hybridisation and immediate early nuclear antigen production in cell culture for the rapid detection of human cytomegalovirus in urine.

The sensitivity and specificity of four modes of two assays, immediate early nuclear antigen detection in cell culture (IENAD) at 24 and 48 h post-infection (p.i.) by immunofluorescence using a murine monoclonal antibody, and dot-blot DNA hybridisation with overnight or prolonged autoradiography using the 32P-labelled HindIII J fragment of human cytomegalovirus (HCMV) DNA as probe, were compared for the rapid detection of HCMV in urine. The sensitivity of IENAD was enhanced by low-speed centrifugation at the time of inoculation. DNA hybridisation with overnight autoradiography was significantly less sensitive than IENAD at 24 h p.i. (P less than 0.001), and even with prolonged autoradiography the hybridisation assay was slower and significantly less sensitive than IENAD at 48 h p.i. (P less than 0.02). The specificity of the two assays was virtually 100%. The sensitivity of DNA hybridisation was thus clearly inferior to that of IENAD.

Antigens, Surface↗