PubMed Health⌕ Search

Biomedical subjects

D M Logan

Publications and source records attributed to D M Logan.

At least 19 recordsLinked to original sources
PubMed1998

How interested is the public in genetic testing for colon cancer susceptibility? Report of a cross-sectional population survey.

OBJECTIVE: To assess the public's interest in genetic testing for colon cancer susceptibility, to determine whether provision of information about the accuracy of the test or the population risk of inheriting the colon cancer gene influences interest, to determine the reasons for wanting to be tested and to identify the factors related to interest in testing. DESIGN: A cross-sectional random digit dialing telephone survey of 501 adults. SETTING: Ontario. MAIN OUTCOME MEASURES: Proportion of the public interested in genetic testing; reasons for interest in testing. RESULTS: Of the sample, 39.9% (95% confidence interval [CI] 35.5 to 44.3) stated that they would be very interested in taking a simple blood test if a positive result suggested they had an 80% chance of getting colon cancer sometime during their lifetime. When it was suggested that the test might be accurate only 90% of the time, 33.1% of the sample (95% CI 28.7 to 37.5) still said they would be very interested in testing. When informed that less than 1% of the population inherits the gene for colon cancer, the proportion of the sample stating they would still be very interested in genetic testing fell to 19.2% (95% CI 14.8 to 23.6). The main reasons given for wanting genetic testing were to take preventive action, for peace of mind and curiosity. For respondents who remained interested in testing after being given information about the population risk of inheriting the gene, 2 factors were identified by logistic regression analysis as being independently related to interest: worry about cancer and perceived risk of getting colon cancer. CONCLUSIONS: If the public's interest in testing for colon cancer susceptibility has any influence on its eventual request to be tested, then demand for genetic testing may be considerable once such tests become widely available and known to the public. This study reveals that the public's interest in genetic testing is substantial, although modifiable by the provision of information about the population risk of inheriting a colon cancer gene. This finding suggests that genetic researchers and others should be careful to provide the population risk of inheriting cancer genes when discussing the discovery of these genes with the media. Furthermore, public health educators will need to ensure that information aids include material on familial risk criteria, genetic counselling and genetic testing, as well as on the implications of genetic testing, the general population risk of developing colon cancer and the general population risk of carrying the colon cancer gene. This information should also be provided to those who seek assessment, to health care professionals and to the public.

Adolescent↗
PubMed1998

Capturing tumour stage in a cancer information database.

OBJECTIVE: 1. To present the steps taken and lessons learned from one cancer centre's efforts to capture tumour stage information in a cancer database. 2. To determine the accuracy of the stage data through a chart audit. 3. To describe the potential uses of stage information in a cancer centre. DESIGN AND SETTING: This is a retrospective review of an initiative to capture tumour stage information at a regional cancer centre in Ontario. DATA SOURCES: The minutes of the centre's Health Records and Medical Advisory Committees related to staging were reviewed. Data on stage by tumour type was extracted from the centre's Oncology Patient Information System (OPIS). Three hundred and ninety charts were analysed to assess the accuracy of stage information and identify staging errors. Health Information Services workload statistics were reviewed to determine the types and frequency of projects undertaken using stage-related data. RESULTS: In January 1994, the Ottawa Regional Cancer Centre introduced policies and procedures to capture stage-related information. Standardized staging forms and a physician reminder system encouraged the centre's physicians to record tumour stage within 3 months of new patient registration. Of all qualifying cases in 1994, 92% were staged. A medical audit in 1998 of 390 charts from the 3 previous years of staging data revealed that 71.5% of the charts reviewed had been staged completely. Of the incompletely staged cases, 19% to 57% had TNM recorded, but the stage grouping was not recorded, or the "stage" was the extent of disease at the time of disease progression rather than at initial diagnosis (35% to 71%). Physician-related staging errors occurred in 2% to 5% of cases; data-entry errors occurred in 3% to 6% of cases. CONCLUSIONS: Stage information has enabled the centre to better describe its patient clientele for accreditation purposes and to assist researchers in estimating the number of patients potentially available for prospective and retrospective studies. It is being used to guide targeted educational initiatives to selected populations in the region's catchment area and assists administrators in estimating resource needs. Resistance to the capture of stage information can be overcome with persistence, the development of procedures that facilitate physician compliance, including a reminder system, the development of institutional policies and procedures and by feedback on the uses and availability of stage information.

Accreditation↗
PubMed1997

Use of vinorelbine in non-small-cell lung cancer. Provincial Lung Disease Site Group.

GUIDELINE QUESTION: Is there a role for the use of vinorelbine in the treatment of patients with non-small-cell lung cancer (NSCLC)? OBJECTIVE: To make recommendations about the use of vinorelbine in the management of patients with NSCLC. OUTCOMES: Survival is the primary endpoint of interest. Response and toxicity are secondary endpoints. PERSPECTIVES: Evidence was selected and reviewed by the 4 members of the Lung Disease Site Group (Lung DSG). Early drafts of this practice guideline were reviewed by the Lung DSG and by the Systemic Treatment Program Committee (STPC). These committees comprise medical and radiation oncologists, pathologists, surgeons, epidemiologists, pharmacists, nurses, a psychologist, a medical sociologist and administrators. No consumers participated in the development of this guideline. QUALITY OF EVIDENCE: Only evidence from randomized controlled trials (RCTs) and phase II studies was evaluated. Six RCTs and 5 phase II studies were reviewed and are discussed in this report. Of the 6 RCTs, 3 have been fully published. BENEFITS: Vinorelbine, either as a single agent or in combination with cisplatin, produces higher response rates (12%-37%) than other single agent vinca alkaloids (10%-20%) in patients with previously untreated NSCLC. Two of 3 RCTs that reported survival differences demonstrated a survival benefit for previously untreated patients with NSCLC when treated with vinorelbine in combination with cisplatin as compared with patients treated with either vindesine plus cisplatin (p = 0.04) or leucovorin plus 5-fluorouracil (p = 0.03). The third study reported no statistically significant difference between patients treated with vinorelbine alone and those receiving vinorelbine plus cisplatin. HARMS: The major toxic effects are hematologic. Neutropenia is the dose-limiting toxic effect. However, there is less neurotoxicity than with other vinca alkaloids (e.g., vindesine) and less nausea and vomiting than with other active agents used in the treatment of NSCLC. PRACTICE GUIDELINE: Evidence from randomized controlled trials supports the use of vinorelbine as an option for the first-line treatment of patients with locally advanced or metastatic NSCLC. Whether vinorelbine is used as a single agent or in combination with cisplatin depends on the anticipated trade-offs between the expected symptomatic benefits of a higher response rate with the combination (as seen in randomized controlled trials) and the increased toxicity. Evidence for a possible survival advantage for the combination of vinorelbine and cisplatin over vinorelbine alone is conflicting. There is insufficient evidence at the present time to advocate the use of vinorelbine in previously treated patients who have recurrent or progressive disease. Similarly, there is insufficient evidence at the present time to advocate the use of vinorelbine as adjuvant or induction therapy for patients with stage I, II or early stage III disease. The enrolment of patients with NSCLC in clinical trials is encouraged.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Adjuvant radiotherapy and chemotherapy for stage II or IIIA non-small-cell lung cancer after complete resection. Provincial Lung Cancer Disease Site Group.

GUIDELINE QUESTIONS: 1) Does the use of postoperative, adjuvant radiotherapy or chemotherapy, alone or in combination, improve survival rates among patients with completely resected, pathologically confirmed stage II or IIIA non-small-cell lung cancer (NSCLC)? 2) Does the use of radiotherapy reduce the risk of local recurrence among patients with completely resected stage II or IIIA NSCLC? OBJECTIVE: To make recommendations about the use of postoperative adjuvant radiotherapy and chemotherapy in the treatment of patients with completely resected stage II or IIIA NSCLC. OUTCOMES: Overall survival and disease-free survival are the primary outcomes of interest. A secondary outcome of interest is local disease control. PERSPECTIVES (VALUES): Evidence was collected and reviewed by 4 members of the Lung Cancer Disease Site Group (Lung Cancer DSG) of the Cancer Care Ontario Practice Guidelines Initiative. The evidence-based recommendation resulting from this review was approved by the Lung Cancer DSG, which comprises medical oncologists, radiation oncologists, pathologists, surgeons and a medical sociologist. A community representative was present at 1 meeting during which the recommendation was discussed. QUALITY OF EVIDENCE: One meta-analysis and 22 randomized controlled trials (RCTs) were published between 1962 and 1996. The RCTs compared surgery plus radiotherapy with surgery alone; surgery plus adjuvant chemotherapy with surgery alone; surgery plus radiotherapy with surgery plus both chemotherapy and radiotherapy. Many studies included patients with stage IIIB NSCLC; some included patients with incompletely resected stage I NSCLC or with small cell lung cancer (maximum 10%). Older studies used chemotherapy or radiation that would now be considered inferior according to current standards of practice. BENEFITS: There was no survival benefit with adjuvant radiotherapy alone, although 3 RCTs reported a reduction in the rate of local recurrence among patients treated with adjuvant radiotherapy. The meta-analysis showed that postoperative, cisplatin-based chemotherapy alone reduced the relative risk of death by 13% (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.74 to 1.02); in combination with radiotherapy it resulted in a 6% reduction in the relative risk of death (HR 0.94, 95% CI 0.79 to 1.11). HARMS: Postoperative adjuvant chemotherapy with alkylating agents was found in the meta-analysis to increase the relative risk of death by 15%. A study involving prolonged adjuvant chemotherapy (busulfan or cytoxan daily for 2 years) reported that 4 of 726 patients had hematologic malignancies. In 1 study, only 53% of patients received all 4 cycles of chemotherapy with cyclophosphamide-doxorubicin-cisplatin (CAP); in another, 22% of patients refused therapy with CAP because of nausea and vomiting. PRACTICE GUIDELINE: There is evidence from RCTs that postoperative radiotherapy reduces rates of local recurrence by 11% to 18% (or 1.6 to 19-fold) among patients with completely resected, pathologically confirmed stage II or IIIA NSCLC. Therefore, if the outcome of interest is a reduction in the frequency of local tumour recurrence, radiotherapy is recommended. However, there is no evidence of a survival benefit from postoperative radiotherapy alone. In a meta-analysis, postoperative chemotherapy with or without radiotherapy resulted in a slightly reduced (statistically nonsignificant) risk of death among patients with surgically resected stage II or IIIA NSCLC. The survival benefit was small and achieved only with chemotherapy regimens that produced substantial toxic effects and that are no longer used. Newer chemotherapy regimens are currently being evaluated as adjuvant therapy, but there is insufficient evidence of benefit at this time to recommend them. Therefore, if the outcome of interest is survival, there is insufficient evidence to recommend current chemotherapy regimens with or without radiotherapy as postoperative, adjuvant the

Carcinoma, Non-Small-Cell Lung↗
PubMed1995

Oral etoposide and carboplatin. Effective therapy for elderly patients with small cell lung cancer.

PURPOSE: Elderly patients with small cell lung cancer (SCLC) and/or those with comorbid conditions are frequently not considered candidates for standard combination chemotherapy. An active, but less toxic regimen is needed for this group of patients. PATIENTS AND METHODS: Forty-seven elderly (> 65 years) or medically unfit patients with SCLC were treated with oral etoposide 100 mg/m2 x 7 days and carboplatin 150 mg/m2 day 1. Treatment was given every 3-4 weeks for six cycles in responding patients. Patients responding to the chemotherapy regimen were also treated with prophylactic cranial irradiation, and limited-stage patients received thoracic radiotherapy. The study population included 36 extensive-stage patients and 11 limited-disease patients with renal or cardiac disease that precluded standard chemotherapy. The median age of the study population was 69 years (range: 47-84). RESULTS: Nine of 47 patients were inevaluable for response, including four patients who succumbed to sepsis. Of the 38 patients evaluable for response, 71% responded (95% CI: 56-86%) (88% LD; 67% ED) with a complete response in 29% of patients (50% LD; 23% ED). Based on an analysis of intent to treat, the overall response rate was 60% and the median survival time of the whole group was 46 weeks (LD, 59 weeks; ED, 45 weeks). Treatment was generally well tolerated. Neutropenia was the dose-limiting toxicity; the median nadir granulocyte count was 1.04 x 10(9)/L (range: 0-8.2). CONCLUSION: We conclude that this regimen can provide palliation to SCLC patients who might not otherwise be considered for systemic chemotherapy.

Aged↗
PubMed1993

Limitations in the use of SSCP analysis.

Since its introduction in 1989, analyses by SSCPA of DNA sequences containing mutations by SSCPA have increased dramatically. While many workers have recognised the utility of the technique, few have examined its limitations. In this paper we report studies using part of the lacI gene from E. coli to measure assay variables. When assay conditions are carefully controlled, the assay is very reproducible. The position and type of mutation have little effect on detection efficiency and changes in sequences 176 and 354 bp in length are detected with comparable efficiencies. Overall detection efficiency is > 90% under most conditions. However, local heating due to excessive power levels, can introduce anomalies.

Base Sequence↗
PubMed1993

Improved polymerase fidelity in PCR-SSCPA.

Polymerase fidelity is important in any application of the polymerase chain reaction (PCR). In single-strand conformation polymorphism analysis (SSCPA) where one may be looking for a small number of altered DNA strands in the presence of thousands of unchanged strands it is critical. We have examined the effect of PCR conditions, product purification and SSCP analysis on the measured error rates with 4 thermostable polymerases (Taq, Vent, Pyrostase and Pfu). Error rates have been calculated by densitometric scanning of SSCPA gel images. Using PCR conditions which maximize fidelity and eliminating products which include large additions or deletions we have achieved error rates of 10(-5) to 10(-6). Such low rates heighten the probability that relatively infrequent mutations will be identified. Further, the densitometric scanning of gel images provides a useful modification of conventional SSCPA which facilitates such identification.

DNA-Directed DNA Polymerase↗
PubMed1992

The use of Tradescantia and Vicia faba bioassays for the in situ detection of mutagens in an aquatic environment.

Tests have shown plant bioassays to be excellent for mutagenicity studies. Most studies with plant bioassays, however, have been carried out either in the laboratory, or if, in situ, as monitors of atmospheric contaminants. The primary purpose of this study was to assess the utility of in situ plant mutagenicity bioassays in monitoring water contaminants. The assay systems tested were the Tradescantia stamen hair and micronucleus assays for the detection of gene mutations and chromosomal aberrations respectively, and the Vicia faba bioassay system which detects chromosomal aberrations in root tips. The assays were used to test the effluent from a pulp and paper mill located on the north shore of Lake Superior. Assays were performed in a creek containing raw effluent and in the bay of Lake Superior into which the creek emptied. All in situ treatments were carried out for 24 h. The effluent from the creek was heavy with pulp and debris which coated the plant cuttings and the Vicia faba seedlings and may have restricted the uptake from the effluent. In the creek, at test sites 11.5 km from the source, the effluent was toxic to the Vicia faba roots as evidenced by a reduction in the mitotic index. The data for the Tradescantia stamen hair assay in the creek were equivocal. The cuttings from the creek test sites and the air and water control sites appeared to have undergone a physiological delay. Within a day or two after the return to the laboratory, that is 6-8 days after testing, flowering almost ceased and did not fully resume until about day 35. This reduction in flowering was particularly severe with the cuttings from the effluent and air control sites, making it very difficult to interpret the results. In contrast, the Tradescantia micronucleus and Vicia faba chromosomal aberration data were unequivocal; each produced positive responses at both test sites relative to the air and water controls. The results obtained for the bay sites with all 3 assays were in agreement. In that section of the bay visibly contaminated by the creek effluent, increases in stamen hair mutants, micronuclei, and chromosome aberrations were measured. In general, there was a considerable reduction in the number of mutant events observed for the water samples brought back from the test sites and tested in the laboratory.(ABSTRACT TRUNCATED AT 400 WORDS)

Canada↗
PubMed1992

Cholesterol alterations in young dystrophic mice.

Cholesterol and cholesteryl ester concentrations and cholesteryl ester fatty acid substituents have been measured during the first 10 weeks of life in tissues of normal and dystrophic mice. In normal Swiss and 129ReJ(+/?) mice the concentrations of both cholesterol and cholesteryl esters remain essentially constant in liver, increase in brain and fall sharply in both thigh (mixed fiber type muscles) and chest muscles (predominantly slow oxidative muscles) over this period. In all cases the concentration of free cholesterol exceeds that of esterified cholesterol. In dystrophic mice, similar patterns are found in brain and liver. In both thigh and chest muscles, however, the developmental pattern is significantly different. After an initial decrease the concentrations of cholesterol and cholesteryl esters increase rapidly with the largest increase occurring in the concentration of cholesteryl esters which by 10 weeks of age exceeds the concentration of cholesterol in chest muscle. During the same period the pattern of esterified fatty acids changes gradually in dystrophic tissues towards an increasing ratio of unsaturated/saturated fatty acids. By 10 weeks of age this ratio is significantly higher in dystrophic tissues than normal in all tissues tested.

Animals↗
PubMed1990

Cholesterol metabolism in dystrophic mice. II. Altered enzyme activities.

In a previous study we found that free cholesterol (FC) and cholesterol ester (CE) concentrations in fast-glycolytic (FG) muscle tissue from dystrophic mice are significantly higher than normal. This increase is not due to an increased capacity for de novo cholesterol biosynthesis. HMG-CoA reductase (HMGR) (the enzyme which catalyzes the rate limiting step) activity is significantly decreased in dystrophic muscle compared to normal. This decrease is paralleled by an increased capacity for both CE production and hydrolysis, i.e., both Acyl-CoA:cholesterol acyltransferase (ACAT) activity and the activities of both lysosomal and sarcoplasmic cholesterol ester hydrolases (CEH) are greatly increased. These enzyme changes in dystrophic FG muscle are similar those observed in normal tissues with elevated levels of cholesterol, which suggests that such changes are not the cause of the altered cholesterol concentrations but are rather the response of the tissue to elevated levels of cholesterol.

Animals↗
PubMed1990

AIDS Kaposi sarcoma-derived cells produce and respond to interleukin 6.

Cell lines derived from Kaposi sarcoma lesions of patients with AIDS (AIDS-KS cells) produce several cytokines, including an endothelial cell growth factor, interleukin 1 beta, and basic fibroblast growth factor. Since exposure to human immunodeficiency virus increases interleukin 6 (IL-6) production in monocytes and endothelial cells produce IL-6, we examined IL-6 expression and response in AIDS-KS cell lines and IL-6 expression in AIDS Kaposi sarcoma tissue. The AIDS-KS cell lines (N521J and EKS3) secreted large amounts of immunoreactive and biologically active IL-6. We found both IL-6 and IL-6 receptor (IL-6-R) RNA by slot blot hybridization analysis of AIDS-KS cells. The IL-6-R was functional, as [3H]thymidine incorporation by AIDS-KS cells increased significantly after exposure to human recombinant IL-6 (hrIL-6) at greater than 10 units/ml. When AIDS-KS cells (EKS3) were exposed to IL-6 antisense oligonucleotide, cellular proliferation decreased by nearly two-thirds, with a corresponding decrease in the production of IL-6. The decrease from IL-6 antisense in AIDS-KS cell proliferation was reversed by the addition of hrIL-6. We confirmed that AIDS-KS cells produced IL-6 in vivo by preparing RNA and tissue sections from involved and uninvolved skin from a patient with AIDS Kaposi sarcoma. We detected immunoreactive IL-6 in the involved tumor areas and to a lesser extent in the surrounding normal epidermis. Slot blot hybridization showed a great excess of IL-6 and IL-6-R RNA in involved skin compared to uninvolved skin. These results show that both IL-6 and IL-6-R are produced by AIDS-KS cells and that IL-6 is required for optimal AIDS-KS cell proliferation, and they suggest that IL-6 is an autocrine growth factor for AIDS-KS cells.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Phase II study of flutamide in patients with metastatic breast cancer. A National Cancer Institute of Canada Clinical Trials Group study.

The National Cancer Institute of Canada (NCIC) Clinical Trials Group conducted a phase II study of the oral antiandrogen flutamide in 33 patients with metastatic breast cancer. Eight patients had received no prior systemic therapy for their metastatic disease and 13 had only one site of metastasis. Toxicity occurred in 18 of the 33 patients and was primarily gastrointestinal. It ranged in severity from mild to severe with 4 patients discontinuing treatment early because of nausea, vomiting, diarrhea or stomatitis. One response, of 8 weeks duration, was noted in 29 evaluable patients. We conclude that flutamide does not have meaningful antitumour activity in breast cancer and plan no further trials of the drug in this disease.

Anilides↗
PubMed1988

Dystrophic chick brain lacks a particular neurotrophic factor.

Extracts from normal embryonic chick brain act as "trophic" agents in the newt blastemata assay where they stimulate the incorporation of amino acids into protein. Equivalent extracts prepared from the brains of dystrophic (am/am) chick embryos are apparently devoid of any equivalent activity.

Animals↗
PubMed1987

Acetylcholine receptor density and binding in murine dystrophy.

The concentration and binding characteristics of acetylcholine receptors (AChR) in sarcolemmal fractions from normal and dystrophic mice have been measured. Unlike the results following denervation, AChR concentration (per g wet weight) is unchanged and AChR affinity for two different alpha-neurotoxins is also unchanged. In contrast sarcolemmal ATPase is significantly reduced in dystrophic tissues. These data reaffirm that denervation is a poor model of dystrophy.

Animals↗
PubMed1987

Fiber-specific cholesterol changes in murine dystrophy.

The cholesterol concentration in dystrophic mouse muscle is reported to be increased compared to normal. The muscles studied are, however, composed in most cases of more than one fiber type. As a result, the observed concentration increase may be due to a general increase or may be due to changes in the proportion of individual fiber types which themselves differ in cholesterol concentration. To decide between these possibilities we have measured the cholesterol concentrations (both free cholesterol and cholesterol esters) in normal and dystrophic whole gastrocnemius muscles and compared the values with the concentrations in fast-glycolytic muscle tissue alone. The cholesterol concentrations in both whole and fast-glycolytic sections of dystrophic muscle are increased compared to normal, with the largest increase in the cholesterol ester fraction. Furthermore, the concentration changes in fast-glycolytic fibers are due mainly to cholesterol ester differences in both membrane and sarcoplasm fractions, with differences in the latter being larger. The data show that changes in whole muscle concentrations cannot be ascribed solely to altered fiber type proportions.

Animals↗
PubMed1986

The importance of dose intensity of doxorubicin administration in non-Hodgkin's lymphoma. A case report.

A 30-year-old woman with Stage IIIA diffuse non-Hodgkins lymphoma was treated with doxorubicin, cyclophosphamide, vincristine, and prednisone (CHOP) every 3 weeks. When the cumulative doxorubicin dosage after nine courses of chemotherapy was 515 mg/m2 (average, 57 mg/m2/course and 19 mg/m2/week), the doxorubicin was discontinued. She relapsed 4.5 months later while receiving vincristine, prednisone, and an escalated dosage of cyclophosphamide (CVP) every 3 weeks. Single-agent chemotherapy consisting of weekly doxorubicin was administered for 15 courses (average dose 29 mg/m2/week) and resulted in a complete remission after nine courses. The cumulative dosage of doxorubicin was 955 mg/m2 at the end of the 15 courses. Mild cardiomyopathy was noted on left ventricular gated scan and electrocardiogram (ECG) at the cessation of therapy. Mild congestive heart failure occurred shortly after the discontinuation of the doxorubicin. It responded to treatment with digoxin and diuretics. At present, she has no dyspnea on exertion and no evidence of cardiomegaly on chest x-ray films; she continues to use digoxin alone. She remains in complete remission 29 months after discontinuation of intensive, weekly, single-agent doxorubicin administration (compared to a remission of only 4.5 months from the end of less intensive administration of doxorubicin every 3 weeks as part of combination chemotherapy). This case illustrates that intensive doxorubicin administration may be superior to conventional doxorubicin administration for the treatment of lymphomas, and raises the possibility that weekly administration could be superior to administration of doxorubicin every 3 weeks. Further studies investigating the efficacy of weekly versus conventional scheduling of doxorubicin are warranted in non-Hodgkin's lymphoma, particularly in light of published evidence that weekly doxorubicin administration is also less cardiotoxic than treatment given every 3 weeks.

Adult↗