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L Hoffman-Goetz

Publications and source records attributed to L Hoffman-Goetz.

81 records · Page 5Linked to original sources
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Predicting submaximal oxygen consumption during treadmill running in mice.

Treadmill exercise is the most common form of exercise used in studies involving laboratory rodents. However, oxygen consumption (VO2) is not usually monitored since the measurement of this parameter is particularly difficult in small, exercising animals. The purpose of this study was to develop a regression equation for predicting submaximal VO2 in mice during treadmill running. Twenty female mice of three strains were tested, in an Oxyscan metabolic treadmill, on different days at running speeds of 10, 13, 15, 17, and 20 m/min at a 0% grade. Each mouse was placed in the treadmill chamber for a 10-min period before running commenced. Running speed was increased in 2-min intervals by 5 m/min until the assigned speed was reached. Each mouse then ran for 10 min to reach steady state, followed by another 20 min at the steady-state plateau. During this period a 30-s expired gas sample was collected every minute. Gas samples were analyzed for O2 and CO2, using an Oxyscan gas analyzer. Trials were conducted during the nocturnal phase of the animals' photoperiod, and running speeds were assigned randomly to minimize order effects. This approach provided highly reliable measures of oxygen consumption (r = 0.96). By using the running speeds (10-20 m/min) and the animal's body weight it was possible to predict the submaximal oxygen consumption (mL/min) during running with a high degree of accuracy (i.e., R2 = 0.85). In an independent group of animals (n = 14) we compared the predicted VO2 with the measured VO2. This yielded a good correlation coefficient (r = 0.79) and a low prediction error (+2.4 +/- 2.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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Cancer coverage in mass-circulating Canadian women's magazines.

Mass media can inform health beliefs and shape cancer control behaviours. This study surveyed cancer coverage in 309 issues of Canadian women's magazines for the period 1991-1997. Magazines were selected if 1996 revenue > $10 million and circulation > 500,000; Canadian Living, Chatelaine, Flare and Homemaker's met these criteria. The volume of cancer coverage varied significantly by year and by magazine. However, coverage of specific cancers did not reflect their contribution as a cause of cancer death in Canadian women. The percentage of articles on lung cancer was lower and on breast cancer was higher than the percentage of deaths due to these cancers. All magazines had decreased coverage of lung cancer in 1997 compared to 1991. National cancer resource agencies and research initiatives on breast cancer were infrequently mentioned. These results argue for greater partnerships between the media and health educators to enhance balanced dissemination of cancer control information to Canadian women.

Canada↗
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Quality of breast cancer sites on the World Wide Web.

The Internet is a powerful tool for accessing information about complex health topics. The purpose of this study was to evaluate breast cancer Internet sites using published criteria about website structure. Two searches were undertaken (November 1998 and June 1999) using the Yahoo search engine, providing a sample of 136 unique addresses. The results showed 1) owner's credentials were identified in 31.6% of sites, 2) financial charges were stated in 10.3% of sites, 3) less than 14.0% identified site creation date, 4) 33.1% identified content posting update, 5) 30.1% identified information sources, and 6) just under 88% of sites provided e-mail interactivity. The results indicate variability in breast cancer Internet sites with respect to framework criteria of accountability. We suggest that websites that lack fundamental indicators (such as dating and sources) do not provide the user with fundamental information that could enable informed decision making about site quality.

Breast Neoplasms↗
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Cancer coverage in newspapers serving large and small communities in Ontario.

Local newspapers are an important source of health news, especially in small communities. We describe the amount and type of cancer information in Ontario daily newspapers dichotomized by circulation size (> 400,000 or < 40,000) and community size (> 250,000 or < 25,000 people) for 1991. All cancer articles (n = 1027) in five newspapers with large circulations, serving large communities, and five newspapers with small circulations, serving small communities, were read and evaluated for focus and newsplay. Although large newspapers had an absolute greater number of cancer articles, there were no significant differences by newspaper size in the number of cancer articles per 1,000 pages. Large newspapers included more cancer articles with a scientific vs. human interest focus than did small newspapers (p < 0.001). Large newspapers tended to use wire services whereas small newspapers tended to use staff reporters. Differences in the type and amount of cancer information varies by newspaper and community size, potentially contributing to differences in community cancer information resources.

Health Resources↗
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Exercise training and mouse mammary tumour metastasis.

The present study was designed to address whether exercise influences the experimental metastasis of a mouse mammary tumour; a related issue was the impact of timing of exercise onset relative to tumour exposure on NK and LAK mediated cytotoxicity. After 8 weeks of forced treadmill exercise or voluntary wheel running or remaining sedentary, female BALB/c mice received an intravenous (i.v.) injection of female BALB/c mice received an intravenous (i.v.) injection of MMT line 66 tumour cells. Mice were then randomized into continuation of activity (TT, WW), cessation of activity (TS, WS), initiation of activity (ST, SW) and maintenance of sedentary condition (SS) for three weeks. Tumour control (TC) mice, who were matched to the SS mice for age, received an i.v. injection of heat-killed MMT 66 tumour cells. In total there were 8 groups including the tumour control. The average number of lung tumours did not differ by activity condition; however, the mice in the continuous treadmill group (TT) tended to have a higher tumour multiplicity (162 +/- 22) and those in the treadmill x sedentary condition (TS) tended to have lower tumour multiplicity (109 +/- 16) compared with the other groups except the SW group (95 +/- 15). The lymphokine activated killer activity in the spleen was significantly elevated in the TS (49 +/- 3%) and WS (44 +/- 3%) mice compared with the sedentary animals (30 +/- 3%) (p < 0.003 and 0.05, respectively). NK activity was lower in the mice that had stopped exercising (TS and WS) after injection of tumour compared with sedentary animals. These data suggest that although exercise training influences natural immune cytotoxic mechanisms in vitro, this may not translate into clinically significant changes in tumour burden. The dissociation between natural immunity and tumour outcome may reflect the relative resistance of the tumour line to lysis by natural killer cells. It remains to be tested if infusion of IL-2 (to induce LAK activity) in exercise trained animals results in fewer tumour metastases.

Animals↗
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Exercise training and tumour metastasis in mice: influence of time of exercise onset.

The present study was designed to investigate the factor of timing of activity onset in determining the effects of exercise on experimental metastases. After 9 weeks of wheel running activity (W) or remaining sedentary (S), male C3H/He mice received an i.v. injection of CIRAS 1 tumor cells. Mice were then randomized into sedentary and wheel running groups (SS, SW, WS, WW) for a further 3 weeks. Although the average number of lung tumours did not differ by activity condition, the groups exercised prior to tumour injection had a greater incidence in the lowest tertile of tumour distribution relative to sedentary controls (SS = 8/20 vs. WS = 16/19, p < 0.005; SS vs. WW = 14/18, p < 0.05). In a replication trial, a similar outcome was present in the lowest tertile: increased incidence of animals exercised prior to injection (SS = 3/9 vs. WW = 7/9: p < 0.05). These data suggest that exercise training before, but not after, i.v. exposure to tumour reduces the number of lung metastases and that the timing of exercise onset influences the extent of experimental metastasis in this model.

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Effect of acute treadmill exercise on LFA-1 antigen expression in murine splenocytes.

The LFA-1 intercellular adhesion molecule (ICAM), expressed on human and murine CD8+ and natural killer (NK) cells, participates in cytolytic interaction with target cells. This study was designed to determine whether acute exercise alters the activity of CD11a (LFA-1) on NK cells. Fourty male C3H/HeNHSD mice were sacrificed before (sedentary) or at various time points after acute treadmill exercise (30 m/min, 4 degrees slope, 30 minutes). Splenic natural killer cell activity (NKCA) was determined using a standard 51Cr release assay, using fresh splenocytes or splenocytes which had been incubated for 3 days with 100 U rIL-2. 10 micrograms/ml of mAb to LFA-1(anti-CD11a) or an equal volume of culture medium were added to the effector:target suspensions prior to 4.5 h incubation. There was a significant main effect of antibody treatment on cytolysis of tumour targets by fresh and IL-2 augmented splenocytes (p < 0.001); for both fresh and IL-2 augmented splenocytes, addition of anti-CD11a antibody reduced cytolysis of tumour target cells. Further, there was a significant main effect of exercise on fresh (p < 0.01) but not IL-2 augmented splenocytes cytolysis; this effect was due to differences in cytolytic activity between 30 and 120 minutes post exercise. Calculation of delta% in cytotoxicity showed that the capacity of mAb to CD11a to inhibit cytolysis was the lowest at 30 minutes after exercise (25%). The delta% in cytotoxicity was less pronounced in samples obtained from IL-2 augmented splenocytes, irrespective of timing of exercise. These results suggest that acute exercise renders mouse splenocytes more resistant to the blockade effect of anti--CD11a (LFA-1) and, as result, may alter killing of tumour target cells in vitro.

Animals↗
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Cultural barriers to cancer screening among African American women: a critical review of the qualitative literature.

There have been numerous studies demonstrating the enormous cancer burden for African American women and the impact of structural barriers in the dissemination of cancer control interventions. Few of these studies have dealt with the influence of cultural factors in the success or failure of intervention research. The purpose of this review is to provide a critical appraisal of qualitative studies that inform on social-cultural factors in cancer screening programs for African American women, and to evaluate the extent to which general methodologic criteria have been used in these studies. The article discusses the theoretical underpinnings of social science qualitative methodologies, including ethnography, hermeneutics, ethnomethodology, and symbolic interactionism. Published qualitative studies from 1980 to 1996 on cancer screening among African American women are critically reviewed. Among the themes identified were bruises as contributory to breast cancer development; the low priority women placed on personal preventive screening behaviors in the context of other family health priorities; and the importance of female friends, relatives, and social networks in the flow of cancer information. The importance of qualitative approaches to cancer prevention and control programs and policies is threefold: (a) collection of greater depth of information, (b) identification of processes and relations among behaviors, and (c) framing of variables and hypotheses for quantitative research. Greater emphasis on methodologic rigor will be necessary, however, if qualitative studies of cancer screening are to effectively inform the development of research, programs, and policies.

Black or African American↗