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Biomedical subjects

G Smart

Publications and source records attributed to G Smart.

18 recordsLinked to original sources
PubMed2001

The use of 188Re to treat in-stent re-stenosis of coronary arteries.

A pilot study has been conducted in which coronary arteries subject to re-stenosis after angioplasty and stenting have been irradiated following further angioplasty. The method of irradiation has been to use radioactive 188Re in an angioplasty balloon. This paper considers all aspects of the procedure including elution of the rhenium from a tungsten/rhenium generator, its concentration, dispensing and safe delivery to the patient using specially designed equipment to reduce staff doses and radioactive spills. In the pilot study of 28 lesions in 26 patients only 1 was recorded as having angiographic re-stenosis in the treated region at 6 months although 4 other patients had edge re-stenosis. This represents less than 18% re-stenosis in a population that would have been expected to exhibit at least 50% re-stenosis at 6 months. A total of 72 patients have been treated either in the pilot study or a subsequent trial. In only one case has a minor spill of radioactivity occurred and in no case has the balloon burst. Radiation doses to staff are approximately 20 microSv per procedure and are therefore not of serious consequence. It is concluded that this procedure is safe, feasible and effective in reducing in-stent re-stenosis.

Angioplasty, Balloon, Coronary↗
PubMed1999

Gnotobiological study of infective juveniles and symbionts of Steinernema scapterisci: A model to clarify the concept of the natural occurrence of monoxenic associations in entomopathogenic nematodes.

Gnotobiology of Steinernema scapterisci and bacteriological study of its symbiont confirmed that this nematode harbors a symbiotic species of Xenorhabdus, as do other Steinermena species. Based on phenotypic and 16S rDNA data, this Xenorhabdus strain UY61 could be distinguished from other Xenorhabdus species. Bacteria reported previously as being associated with this nematode and belonging to several other genera were probably contaminating bacteria located in the intercuticular space of the infective juveniles (IJs). These bacteria were detrimental to nematode reproduction in Galleria mellonella. Axenic S. scapterisci and its symbiont Xenorhabdus strain UY61 alone were not pathogenic to G. mellonella. The combination of both partners reestablished the pathogenicity of the complex toward G. mellonella. This combination also gave the best yields of IJs when produced in this insect and in vitro production on artificial diet.

Animals↗
PubMed1999

Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population.

The living conditions of many aboriginal communities in Canada may place their residents at risk for H. pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) if H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collected from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H. pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and of hospitalizations associated with diagnoses of peptic ulcer were determined for the Indian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the amplicons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the time of the study were enrolled. The ELISA for H. pylori was positive in 291 (95%). There was no association between H. pylori seropositivity and age, sex, gastrointestinal complaints, medications, housing characteristics, and ABO or Lewis antigen status. CagA was positive in 84.5% of infected subjects. The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-status Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gastric cancer rates were similar (11.2/100,000 vs 11.6/100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of CagA-positive H. pylori is high in this representative Manitoban Indian community. This may be associated with an increased risk for peptic ulcer disease but is not associated with an increased risk for gastric cancer.

Adolescent↗
PubMed1999

The use of GAFchromic film to determine the absolute activity of beta emitters.

A method of using GAFchromic film to determine the absolute activity of beta emitters by immersing the film in a bath of activity is described. This includes calculations of the effect of part of the radioactive solution being displaced by the film that is performing the measurement. Calculations have been performed for 90Y, 32P and 188Re. It is shown that for the film used in this study, this effect will cause a correction of the order of 15-20% for the three radionuclides studied. The results of the GAFchromic film measurement are compared with results obtained from liquid scintillation counting and from a commercial dose calibrator. It is shown that for 32P all methods were in reasonable agreement, but for 188Re, although the GAFchromic film and the liquid scintillation counting methods give similar results, the dose calibrator measurement differed by more than 20%. The GAFchromic film was also used to perform a direct measurement of the radiation dose at a distance of 0.5 mm from the surface of a cylindrical source of 188Re activity. This gave good agreement with the value of the dose predicted from theoretical calculations.

Beta Particles↗
PubMed1999

Helicobacter pylori in the Canadian arctic: seroprevalence and detection in community water samples.

OBJECTIVE: Many North American arctic communities are characterized by risk markers associated with Helicobacter pylori (H. pylori) infection, including overcrowded housing and inadequate water supply and sanitation systems. Our aim was to determine the seroprevalence of H. pylori infection in two traditional Inuit communities in the central Canadian arctic and to test for the presence of H. pylori, by polymerase chain reaction (PCR), in local water supplies. METHODS: Samples of venous whole blood from adults and capillary blood from children were collected and analyzed by enzyme immunoassay and Helisal Rapid Test, respectively, for IgG antibody to H. pylori. Antibodies to CagA were detected by enzyme immunoassay, and ABO and Lewis antigens were also determined. Demographic and clinical information were collected by questionnaire. Water samples from each community were tested for H. pylori by PCR. RESULTS: One hundred-thirty (50.8%) of 256 subjects from the two communities were positive for H. pylori IgG antibodies. Seropositive subjects were more likely to be male, compared with seronegative individuals (p = 0.01). Antibody status did not differ with respect to age, community, alcohol or cigarette use, number of persons per household, gastrointestinal complaints or previous investigations, medications, or presence of blood group O, Lewis a-b+. CagA antibodies were detected in 78 (61.9%) of 126 H. pylori-seropositive subjects tested; however, 41 (35.3%) of 116 H. pylori-seronegative subjects were also CagA positive. Water samples taken from the water delivery truck in Chesterfield Inlet and two lakes near Repulse Bay were positive for H. pylori. CONCLUSION: The seroprevalence of H. pylori in the study group was higher than rates in southern Canadian populations, but lower than the seroprevalence previously documented in a Canadian subarctic Indian (First Nations) community. The detection of H. pylori in local water supplies may indicate a natural reservoir for the organism or possible contamination from human sewage.

ABO Blood-Group System↗
PubMed1988

Heart Link.

Explore the source record for details and available documents.

Child↗
PubMed1984

Extradural analgesia and ichthyosis.

Extradural analgesia is well established for relief of pain but in certain cases unusual difficulties may be encountered. We report our experiences of a patient with congenital ichthyosis who required extradural analgesia for the relief of pain in labour.

Adult↗
PubMed1983

Radioimmunoassay of O6-methyldeoxyguanosine in DNA of cells alkylated in vitro and in vivo.

Mouse monoclonal and rabbit polyclonal antibodies have been prepared against O6-methylguanosine complexed with bovine serum albumin. In radioimmunoassay 50% inhibition of binding of [3H]O6-methyldeoxyguanosine (O6-MedG) was obtained with 0.3 pmol or 0.16 pmol unlabelled O6-MedG using monoclonal or polyclonal antibodies having affinity constants of 3.0 X 10(9) and 5.9 X 10(9) I mol-1 respectively. Cross-reactivity with normal nucleosides and other adducts was determined. Sensitivity and reproducibility were improved by chromatographic separation using an Aminex A6 column eluted with 10 mM NH4HCO3 buffer which allowed quantitation of one molecule O6-MedG per 10(7) molecules dG in 2 mg calf thymine DNA. Values for O6-MedG from 14 samples of rat liver and kidney DNA analysed by the method described and by radiochromatography on Sephadex G10 were almost identical (correlation coefficient, 0.98). A modified procedure for the purification of 5-25 micrograms DNA from 1-5 X 10(6) fibroblasts applied to polycarbonate filters was used in providing further validation of the RIA system by measuring the persistence of O6-MedG in cell lines of known repair capacity.

Alkylation↗
PubMed1982

Assessment of lead intakes and dose-response for a population in Ayr exposed to a plumbosolvent water supply.

1 Dietary lead intakes, blood lead concentrations and water lead concentrations were measured and their relationships investigated for 31 adults and 11 infants living in dwellings in Ayr with lead plumbing. 2 For adults, some lead intakes were found to be higher than the provisional tolerable weekly intake for lead, and for infants most of the intakes were high. 3 A cube root relationship fitted the data on blood lead versus water lead better than a linear relationship. Similarly, blood lead varied with the cube root of weekly dietary lead intake. 4 These cube root equations provided a means of estimating the impact on blood lead concentrations of exposure to lead from food and water. If cube root relationships correctly describe the association between these parameters, then the curve fitted to the results for adults indicates that the contribution to the blood lead concentrations from sources other than the diet and water was relatively small.

Adult↗
PubMedDate not supplied

Early changes in hepatitis C virus (HCV) RNA levels predict response to interferon treatment in noncirrhotic HCV patients.

UNLABELLED: The role of hepatitis C virus (HCV) RNA quantification in determining ideal interferon (IFN) treatment of noncirrhotic HCV liver disease is uncertain. The specific aim of this study was to determine whether measurement of baseline HCV RNA or changes in HCV RNA levels (DHCV RNA) early during therapy predict response to IFN alpha in noncirrhotic HCV patients. PATIENTS AND METHODS: Twenty-one noncirrhotic patients with chronic HCV were treated with 3 MU IFN alpha-2a three times per week. HCV RNA levels were determined at baseline and after two, four, six, eight and 12 weeks of treatment. Baseline HCV RNA and DHCV RNA during therapy were compared with treatment response results at six months. Data were expressed as mean +/- SE, and differences were assessed using Student's t test. RESULTS: Twenty-one patients initiated IFN alpha therapy. Two patients were noncompliant and lost to follow-up. One patient discontinued IFN alpha due to side effects. Apart from age, where responders tended to be younger than nonresponders, the baseline clinical characteristics and alanine aminotransferase (ALT), aspartate aminotransferase, bilirubin and HCV RNA levels did not differ between IFN alpha responders and nonresponders. Levels of HCV RNA were significantly lower after both two and four weeks of therapy in IFN alpha responders compared with nonresponders (P<0.001). Changes in log HCV RNA levels after both two and four weeks of therapy were significantly greater in IFN alpha responders compared with nonresponders (P<0.001). Changes in log HCV RNA of more than 1.0 after two weeks of IFN alpha therapy identified all six-month responders, with a sensitivity of 100% and a specificity of 89%. Potential financial impact of these findings on patients' management was also calculated. Decisions regarding discontinuation of therapy based on early changes in HCV RNA levels would result in a 40% to 50% reduction in IFN alpha cost. CONCLUSIONS: In noncirrhotic HCV patients, the change in quantitative HCV RNA after the first two weeks of IFN alpha therapy identifies responders. This finding would result in a 40% to 50% cost savings if decisions about continuing IFN alpha were based on early changes in HCV RNA levels rather than ALT or HCV RNA assessment after the completion of three months of IFN alpha treatment.

Adult↗