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Biomedical subjects

G Long

Publications and source records attributed to G Long.

71 records · Page 4Linked to original sources
PubMed1971

Primary FFARACS.

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Education, Medical↗
PubMedDate not supplied

Induction of urinary bladder hyperplasia in Sprague-Dawley rats orally administered tri-n-butyl phosphate.

The effects of tri-n-butyl phosphate (TBP) were investigated in the Sprague-Dawley rat over an 18-wk period. Groups of randomized female (average weight [AW] = 206 +/- 10 g) and male (AW = 294 +/- 13 g) rats were divided into low-dose, high-dose, and control groups (12 rats/sex X group). Tri-n-butyl phosphate was administered by gavage once a day for 5 days/wk over an 18-wk period. Low-dose animals received 0.20 g/kg X day throughout the experiment and high-dose animals received 0.30 g/kg X day for the first 6 wk. For the remaining 12 wk, the high-dose level was increased to 0.35 g/kg X day. Histopathological examination of tissues revealed that all test rats examined developed diffuse hyperplasia of the urinary bladder epithelium. Similar changes were not found in the control animals.

Administration, Oral↗
PubMedDate not supplied

Chloroform: exposure estimation, hazard characterization, and exposure-response analysis.

Chloroform has been assessed as a Priority Substance under the Canadian Environmental Protection Act. The general population in Canada is exposed to chloroform principally through inhalation of indoor air, particularly during showering, and through ingestion of tap water. Data on concentrations of chloroform in various media were sufficient to serve as the basis for development of deterministic and probabilistic estimates of exposure for the general population in Canada. On the basis of data acquired principally in studies in experimental animals, chloroform causes hepatic and renal tumors in mice and renal tumors in rats. The weight of evidence indicates that chloroform is likely carcinogenic only at concentrations that induce the obligatory precursor lesions of cytotoxicity and proliferative regenerative response. Since this cytotoxicity is primarily related to rates of formation of reactive, oxidative metabolites, dose response has been characterized in the context of rates of formation of reactive metabolites in the target tissue. Results presented here are from a "hybrid" physiologically based pharmacokinetic (PBPK) animal model that was revised to permit its extension to humans. The relevant measure of exposure response, namely, the mean rate of metabolism in humans associated with a 5% increase in tumor risk (TC05), was estimated on the basis of this PBPK model and compared with tissue dose measures resulting from 24-h multimedia exposure scenarios for Canadians based on midpoint and 95th percentiles for concentrations in outdoor air, indoor air, air in the shower compartment, air in the bathroom after showering, tap water, and food. Nonneoplastic effects observed most consistently at lowest concentrations or doses following repeated exposures of rats and mice to chloroform are cytotoxicity and regenerative proliferation. As for cancer, target organs are the liver and kidney. In addition, chloroform has induced nasal lesions in rats and mice exposed by both inhalation and ingestion at lowest concentrations or doses. The mean rate of metabolism associated with a 5% increase in fatty cysts estimated on the basis of the PBPK model was compared with tissue dose measures resulting from the scenarios already described, and lowest concentrations reported to induce cellular proliferation in the nasal cavities of rats and mice were compared directly with midpoint and 95th percentile estimates of concentrations of chloroform in indoor air in Canada. The degree of confidence in the underlying database and uncertainties in estimates of exposure and in characterization of hazard and dose response are delineated.

Air Pollutants↗
PubMedDate not supplied

An HPLC method for analysis of clonazepam in serum.

A sensitive, accurate, and precise method for the analysis of clonazepam in serum was developed. The drug and internal standard from serum extracts were methylated to obviate carbamazepine interference and then resolved on a 5 micron C18 HPLC column. The mobile phase could also be used for many other basic drugs.

Benzodiazepinones↗
PubMedDate not supplied

Investing in practice: enquiry- and problem-based learning.

Enquiry-based learning (EBL) and problem-based learning (PBL) are two similar methods of educating nurses and midwives which have been recommended by the UKCC in its new report 'Fitness for Practice' (UKCC, 1999). The integration of theory and practice within the student programme is the key to bridging the theory/practice gap. The incorporation of EBL and PBL into the curriculum may help resolve this gap. As these methods of education foster learning through the use of real client scenarios it is important to stress that the partnership between clinical and academic staff is of paramount importance. This article explores EBL and PBL from the practitioner's perspective and examines some of the factors necessary for its successful implementation.

Clinical Competence↗
PubMedDate not supplied

Non-Hodgkin's lymphoma of the paranasal sinuses: clinical and pathological features, and response to combined-modality therapy.

PURPOSE: Lymphomas of the paranasal sinuses may have poorer prognoses compared with other extranodal lymphomas of the head and neck, and are not well defined as a particular clinicopathologic entity. The outcome of combined-modality therapy and central nervous system (CNS) prophylaxis has not been fully determined. PATIENTS AND METHODS: We retrospectively reviewed our experience with 16 consecutive, carefully defined patients, all treated with both chemotherapy and radiotherapy. RESULTS: There were 11 men and five women, mean age 52. All presented with local symptoms; 13 had stage I or II disease. Thirteen had diffuse large cell lymphoma, two diffuse mixed, and one small noncleaved. Phenotyping revealed 10 B-cell, four T-cell, and two T or natural killer (NK). Most received CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy; the order of chemotherapy and radiotherapy varied. Twelve received CNS prophylaxis. Of 12 complete responses, six relapsed, all at distant sites, and two died during initial therapy. Five-year survival was 29%, and median survival 18 months. Four of 10 B-lineage patients were relapse-free at 4 years; all six T- or T/NK-lineage patients relapsed or were dead within 6 months. Tumors of T or NK lineage often expressed CD56 and showed evidence of Epstein-Barr viral infection; otherwise, pathological features were not predictive of lineage or outcome. Neither age nor lactate dehydrogenase predicted prognosis. No complete responder recurred in the CNS as site of first relapse. CONCLUSION: Despite localized stage at presentation, sinus lymphoma is an aggressive disease, characterized by distant relapse and early mortality. Combined-modality therapy with CNS prophylaxis improves outcome compared with radiotherapy alone; however, prognosis remains poor. Patients with T-lineage disease appear to have a particularly bad outcome. Autologous bone marrow transplantation should be evaluated as first-line therapy for those at high risk of relapse.

Adolescent↗