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Biomedical subjects

G W Smith

Publications and source records attributed to G W Smith.

At least 127 records · Page 7Linked to original sources
PubMed1986

Seroimmunology of AIDS retrovirus infection. I. Use of immunofluorescence assay to confirm sera with ELISA reactivity.

One thousand sera shown to be reactive by one of two commercial enzyme linked immunosorbent assays (ELISA) for antibodies to the AIDS virus were referred to the NSW State Reference Laboratory for confirmatory assays. Each serum was retested by two commercial ELISA systems (Abbott and ENI), the ENI exclusionary H9 ELISA and an immunofluorescence assay. Three hundred and twenty four sera were reactive by all 3 tests whereas 244 demonstrated concordant non-reactivity. Three hundred and seventy seven sera were reactive by Abbott EIA only and could not be confirmed positive by the ENI ELISA incorporating exclusionary testing, immunofluorescence or Western immunoblot of representative sera. Sera obtained from teaching hospital laboratories were more likely to be positive and less likely to be negative by all 3 tests, and were also less likely to be Abbott EIA reactive only compared with sera obtained from the blood transfusion service. Of the remaining 55 sera, 52 demonstrated a negative immunofluorescent reaction or a pattern of equal fluorescence on AIDS virus infected and control cells. Representative sera were shown to be negative on Western immunoblot analysis. Of the 3 sera which demonstrated immunofluorescence reactivity, one was positive and one was negative by Western immunoblot, and one could not be determined. We conclude that a combination of two ELISAs, one with an exclusionary ELISA test and an immunofluorescence assay is a reliable and simple means of confirming reactive sera for AIDS virus antibodies.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Biliary-bronchial fistula after right hepatic lobectomy.

Biliary-bronchial fistula is an extremely unusual complication of thoracoabdominal trauma or suppurative hepatobiliary disease. We treated a patient with a biliary-bronchial fistula that developed after right hepatectomy for an infected traumatic intrahepatic hematoma. The diagnosis of biliary-bronchial fistula was confirmed by percutaneous transhepatic cholangiography. Surgical therapy included a primary transabdominal choledochostomy, with the insertion of a T-tube, sphincteroplasty, and open marsupialization of the chronic subphrenic abscess.

Adult↗
PubMed1985

Pig gastric mucus: a one-way barrier for H+.

Gastric mucus is thought to protect the underlying mucosal cells from mechanical hazards and back-diffusion of luminal H+. In health, a pH gradient exists across the mucus layer from the variable low pH of the lumen to a pH approaching neutrality at the epithelial cell surface. By current hypotheses this gradient is maintained by the combined effects of an unstirred layer, restricted or slowed diffusion of H+ in the mucus, and the epithelial cell secretion of bicarbonate, which is confined to the cell surface by the mucus layer. These mechanisms do not explain how H+ is secreted through mucus in the first place. Using a modified diffusion chamber we have shown that pig gastric mucus facilitates a low-efficiency Na+/H+ exchange--a property that helps to clarify some previously unexplained components of H+ secretion. When a solution containing Na+ was separated by a layer of fresh pig gastric mucus from a solution of similar pH containing a much lower concentration of sodium, the sodium-rich solution was electrically negative relative to the sodium-poor solution and its pH decreased significantly with time. A similar pH gradient developed when the barrier was a synthetic cation-exchange membrane, and one of opposite sign when it was an anion exchanger; no pH gradient developed across neutral barriers. It is suggested that similar electrical coupling of H+ diffusion to active Na+ transport might in vivo ensure that secreted H+ moves into the gastric lumen.

Animals↗
PubMed1985

A clinical comparison between Macrodantin and trimethoprim for prophylaxis in women with recurrent urinary infections.

Seventy-two patients with a history of at least three attacks of urinary infection in the previous 12 months were assigned randomly to long-term prophylaxis with 100 mg at night of either Macrodantin (34 patients) or trimethoprim (38 patients). The mean interval between symptomatic attacks while on either treatment was increased three-fold compared with the pretreatment period. Macrodantin was significantly more effective (P less than 0.05) at preventing bacteriuria. Prophylaxis was equally effective in patients with and without a radiological abnormality. Side effects were significantly more common (P less than 0.05) in the group taking Macrodantin. In patients taking trimethoprim acquisition of resistance by faecal coliforms occurred at a rate of about 5%/month, and breakthrough infections were almost exclusively caused by trimethoprim-resistant coliforms. No acquisition of resistance occurred in patients taking Macrodantin, and the few breakthrough infections noted were due to sensitive bacteria.

Feces↗
PubMed1985

Successful use of reduced dosage of cinoxacin in the treatment of recurrent urinary infection.

Ninety-seven patients with a history of recurrent bacteriuria were treated with cinoxacin in a dosage of either 250 mg (48 patients) or 500 mg (49 patients) 12-hourly for seven days. Both regimens had a success rate in excess of 85% one week after the end of treatment, and only 15% of the patients rendered abacteriuric had relapsed four weeks later. Both dosage regimens of cinoxacin were very well tolerated. Our results show that in patients with recurrent urinary infections the conventional dosage of cinoxacin (500 mg) can be reduced to 250 mg 12-hourly without any loss of efficacy. Consequently patients seen in family practice with uncomplicated lower tract urinary infection can confidently be expected to respond equally well to a dose of 250 mg 12-hourly with the obvious advantages of less toxicity, less chance of producing resistance in the bowel flora and lower cost.

Adult↗
PubMed1985

Synthesis of proteins and glycoproteins in dengue type 2 virus-infected vero and Aedes albopictus cells.

Fifteen proteins were detected in Vero cells infected by dengue type 2 (DEN-2) virus that were not observed in mock-infected cells, namely P98, p82, P67, GP60, gp54, GP46, p30, p28, gp22, GP20, p18, gp16, p15, p14 and gp13. With the exceptions of gp54 and gp13, polypeptides corresponding to those listed above were also observed in DEN-2 virus-infected Aedes albopictus C6/36 cells. Pulse-chase labelling experiments suggested a possible precursor-product relationship between p30 and p28, and between gp22 and GP20. Peptide mapping and immunoprecipitation experiments showed that the major glycoproteins GP60, GP46 and GP20 were unrelated. Immunoprecipitations of infected cells with antiserum prepared against the DEN-2 soluble complement-fixing (SCF) antigen demonstrated that this antigen is equivalent to the non-structural glycoprotein GP46. The envelope glycoprotein (E) from virus grown in C6/36 cells migrated faster through polyacrylamide gels containing SDS than E from virus grown in Vero cells. [3H]Mannose-labelled glycopeptides of GP60, GP46 and GP20 were separated by gel filtration and by electrophoresis in Tris-borate gels; in addition, the polypeptides synthesized in infected cells in the presence of tunicamycin were analysed. The results revealed heterogeneity among the glycan units of GP60 and GP46.

Aedes↗
PubMed1985

Dopexamine: a novel agonist at peripheral dopamine receptors and beta 2-adrenoceptors.

Dopexamine is an agonist at peripheral dopamine receptors and at beta 2-adrenoceptors. Dopexamine has approximately one-third the potency of dopamine in stimulating the vascular DA1-receptor in the dog, resulting in a fall in renal vascular resistance of 20% at 2.3 X 10(-8) mol kg-1 (i.a.). Prejunctional DA2-receptors are also stimulated by dopexamine, resulting in a reduction of neurogenic vasoconstriction in the rabbit isolated ear artery (IC50 of 1.15 X 10(-6)M) and of neurogenic tachycardia in the cat (ID50 of 5.4 X 10(-8) mol kg-1, i.v.), with a potency six and four times less respectively than that of dopamine. By contrast, dopexamine is approximately 60 times more potent than dopamine as an agonist at the beta 2-adrenoceptor of the guinea-pig isolated tracheal chain, with an EC50 of 1.5 X 10(-6)M. Both dopexamine and dopamine are weak agonists at the guinea-pig atrial beta 1-adrenoceptor over the concentration range 10(-7) to 10(-4) M, but dopexamine has an intrinsic activity of only 0.16 relative to dopamine. Dopexamine does not stimulate postjunctional alpha 1- or alpha 2-adrenoceptors in the canine isolated saphenous vein, whereas dopamine is an agonist, approximately 120 times less potent than noradrenaline. Unlike dopamine and salbutamol, dopexamine does not cause arrhythmias in the guinea-pig isolated perfused heart at doses of up to 10(-5) mol, which is a thousand times the minimum cardiostimulant dose. The combination of agonist properties at peripheral dopamine receptors and at beta 2-adrenoceptors, with little or no activity at alpha- and beta 1-adrenoceptors gives dopexamine a novel pharmacological profile. This may confer advantages over dopamine in the treatment of acute heart failure.

Adrenergic Agonists↗
PubMed1985

The effects of dopexamine on the cardiovascular system of the dog.

The cardiovascular effects of dopexamine and dopamine were compared in the anaesthetized and conscious dog by the use of intravenous infusions over the dose range 3 X 10(-9) - 10(-7)mol kg-1 min-1. In the anaesthetized dog, dopexamine produced a dose-related fall in blood pressure due to peripheral vasodilatation and a small rise in heart rate and contractility. By contrast, dopamine did not significantly reduce blood pressure but produced a larger dose-related increase in contractility. At the highest infusion rate (10(-7)mol kg-1 min-1) blood pressure and heart rate were increased by dopamine. Dopexamine dilated the renal and mesenteric vascular beds with a potency similar to that of dopamine. Femoral vascular responses produced by both agents were inconsistent but the highest infusion rate of dopamine did produce vasoconstriction. With the aid of selective receptor antagonists (haloperidol, propranolol and bulbocapnine) the vasodepressor activity of dopexamine was shown to be mediated by stimulation of DA2-, beta- and DA1-receptors. The cardiac stimulation and renal vasodilatation produced by both compounds were due to stimulation of beta-adrenoceptors and DA1-receptors respectively. In the conscious dog, intravenous infusion of dopexamine caused a dose-related fall in blood pressure, renal vasodilatation and an increase in cardiac contractility and heart rate. Dopamine also increased cardiac contractility, and renal blood flow due to renal vasodilatation but without affecting heart rate. At the highest infusion rate, blood pressure was increased. Dopexamine and dopamine produced a similar incidence of panting and repetitive licking at 3 X 10(-8)mol kg-1 min-1 and emesis at 10(-7)mol kg-1 min-1, due to stimulation of dopamine receptors in the chemoreceptor trigger zone. Dopexamine produces a different cardiovascular profile from dopamine in the anaesthetized and conscious dog. Both compounds reduce renal vascular resistance, but in contrast to dopamine, dopexamine reduces afterload and produces only mild inotropic stimulation. These differences reflect contrasting activity at adrenoceptors.

Animals↗
PubMed1985

A study of the personal meaning of suicide in the context of Baechler's typology.

This study investigates suicide from the vantage point of the suicidal person by analyzing the personal meaning(s) of the act for the individual. Twenty-seven suicidal persons and survivors contributed to the research. Their individual recollections are studied and ordered within the framework of Jean Baechler's approach (as presented in his book Suicides). The study indicates that there is, in each case, an identifiable purpose or a pattern of purposes that can be categorized within a restricted and meaningful system, which may help the observer understand what human beings are doing when they want to end their lives.

Adolescent↗
PubMed1984

Hepatic artery infusion of 5-fluorouracil and mitomycin C in cholangiocarcinoma and gallbladder carcinoma.

Eleven patients with histologically proven cholangiocarcinoma and gallbladder carcinoma were treated with hepatic artery infusion (HAI) of 5-fluorouracil (5-FU) and mitomycin C (Mito-C). Catheters were placed percutaneously through the femoral artery. The schedule used was 5-FU 1200/mg/m2/day given as a continuous infusion for 4 days, plus Mito-C 6 mg/m2 on days 1 and 4. Courses were repeated every 4 weeks. Complete responses (CR) occurred in one patient (9%), and partial response (PR) occurred in six patients (55%). Median survival for all patients from the start of the first treatment was 12.5+ months. Median duration of the response was 3.0 months. Median survival of the patients with gallbladder carcinoma was 12.5 months, and for patients with cholangiocarcinoma has not yet been reached. Drug toxicity was mild, and morbidity of the HAI was minimal. Further trials of chemotherapy in these two neoplasms are warranted.

Adenoma, Bile Duct↗
PubMed1984

Differences in properties between aromatic amino acid: aromatic keto acid aminotransferases and aromatic amino acid: alpha-ketoglutarate aminotransferases.

Homogenates of rat liver transaminate phenylpyruvate (PP), as well as alpha-ketoglutarate (alpha-KG), in the presence of L-tyrosine, 3,4-dihydroxyphenylalanine (L-DOPA) or L-tryptophan. Aminotransferase activity with phenylpyruvate and DOPA, but not with tyrosine, was inhibited by excess phenylpyruvate. Tyrosine and DOPA aminotransferase activities with phenylpyruvate were more heat stable than the corresponding activities with alpha-ketoglutarate. Aminotransferase activities with phenylpyruvate were not significantly induced following intraperitoneal injections of cortisol, glucagon or serotonin, compared with a 3 to 7-fold increase in the aminotransferase activities with alpha-ketoglutarate. Tyrosine:phenylpyruvate aminotransferase activity rose 40% at night, compared with a 300% increase in tyrosine:alpha-ketoglutarate aminotransferase activity. The results suggest that aminotransferases catalysing transfers between aromatic keto acids and aromatic amino acids are separate enzymes from those utilizing alpha-ketoglutarate as the acceptor keto acid.

Animals↗
PubMed1984

C1q binding and C1q deviation assays using enzyme labelled C1q.

Methods for the enzyme labelling of C1q are described. The C1q conjugates have been incorporated into suitably modified C1q deviation and C1q binding assays for circulating immune complexes. These assays show the expected high positivity rate in sera from patients with systemic lupus erythematosus. The assays using enzyme labelled C1q confer considerable advantages over their counterparts using 125I.

Alkaline Phosphatase↗
PubMed1984

Identification of a phosphorylated non-structural form of the P protein of Newcastle disease virus and analysis of P multimers.

Two phosphorylated and two non-phosphorylated variants of P protein isolated from Newcastle disease virions are known. Here, a fifth form of P was identified using two-dimensional polyacrylamide gel electrophoresis and peptide mapping. P form 5 was phosphorylated; however, unlike the four known variants of P, the new form was not a major protein in virions, which suggested an intracellular function. The subunit composition of four electrophoretically distinct, disulphide-linked multimers of P from virions was determined. Each homomultimer was composed of at least three molecules of a different one of the four virion-associated P variants.

Animals↗
PubMed1984

Penicillin concentrations in serum and cerebrospinal fluid after intramuscular injection of aqueous procaine penicillin 0.6 MU with and without probenecid.

Paired specimens of cerebrospinal fluid and serum were taken from 21 patients to estimate penicillin concentrations two to three hours after the last dose of a course of 14-21 daily intramuscular injections of procaine penicillin 0.6 MU. Of 10 patients treated with procaine penicillin alone, eight had no detectable penicillin and two had sub-treponemicidal concentrations (less than 0.018 mg/l) in the cerebrospinal fluid. Of 11 patients treated with procaine penicillin as above and probenecid 2 g a day by mouth, three had no detectable penicillin, two had sub-treponemicidal concentrations, and six had treponemicidal concentrations of penicillin in the cerebrospinal fluid. All 21 patients had treponemicidal concentrations of penicillin in the serum. This dose of procaine penicillin alone or with probenecid is therefore not recommended for treating neurosyphilis.

Biological Assay↗