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Biomedical subjects

D G Altman

Publications and source records attributed to D G Altman.

At least 19 recordsLinked to original sources
PubMed1992

Is the anterior-posterior axis of the fetus specified before implantation in the mouse?

The mouse conceptus is generally held to be radially symmetrical about its embryonic-abembryonic axis from the blastocyst stage until the primitive streak appears at the beginning of gastrulation. However, this notion has been challenged by recent observations on conceptuses sectioned in utero which suggest that the blastocyst is already bilaterally symmetrical when it begins to implant. Accordingly, the blastocyst has been assigned an anterior-posterior axis which appears to persist through gastrulation and is claimed to coincide with the anterior-posterior axis of the future fetus in both orientation and polarity. In the present investigation the relationship between these two axes was examined in conceptuses dissected from the uterus early in gastrulation so that it could be determined more accurately than is possible in situ. The anterior-posterior axis of the conceptus and nascent fetus were found to be either parallel or antiparallel to each other, suggesting that while the orientation of the fetal axis may be specified at the blastocyst stage its polarity is not.

Animals↗
PubMed1992

Policy alternatives for reducing tobacco sales to minors: results from a national survey of retail chain and franchise stores.

Minors' access to tobacco has become an important public health issue. Little is known, however, about the knowledge, attitudes, beliefs, and behavior toward access among executives from businesses that sell tobacco. This study examined access from the perspective of corporate and regional headquarters of retail chains and franchises that sell tobacco. A total of 148 U.S. companies with the largest overall retail sales volume that sold tobacco were asked to participate; 91 agreed. The sample included grocery stores, convenience stores, gas station mini-marts, liquor stores, and drug stores. Data revealed at least moderate support for policies limiting youth tobacco access. Although most companies reported having in place policies to prevent minors from purchasing tobacco, these policies did not seem intensive. In addition, executives underestimated the extent of youth access. We conclude that the time is right for passage of bold policies to protect young people from tobacco.

Adolescent↗
PubMed1991

Predictors of physician's smoking cessation advice.

OBJECTIVES: To determine the percentage of smokers reporting that a physician had ever advised them to smoke less or to stop smoking, and the effect of time, demographics, medical history, and cigarette dependence on the likelihood that respondents would state that a physician had ever advised them to stop smoking. DESIGN AND SETTING: Data were collected from the Stanford Five-City Project, a communitywide health education intervention program. The two treatment and three control cities were located in northern and central California. As there was no significant difference between treatment and control cities regarding cessation advice, data were pooled for these analyses. PARTICIPANTS: There were five cross-sectional, population-based Five-City Project surveys (conducted in 1979-1980, 1981-1982, 1983-1984, 1985-1986, and 1989-1990); these surveys randomly sampled households and included all residents aged 12 to 74 years. MAIN OUTCOME MEASURES: Improved smoking advice rates over time in all towns was an a priori hypothesis. RESULTS: Of the 2710 current smokers, 48.8% stated that their physicians had ever advised them to smoke less or stop smoking. Respondents were more likely to have been so advised if they smoked more cigarettes per day, were surveyed later in the decade, had more office visits in the last year, or were older. In 1979-1980, 44.1% of smokers stated that they had ever been advised to smoke less or to quit by a physician, vs 49.8% of smokers in 1989-1990 (P less than .07). Only 3.6% of 1672 ex-smokers stated that their physicians had helped them to quit. CONCLUSION: These findings suggest that physicians still need to increase smoking cessation counseling to all patients, particularly adolescents and other young smokers, minorities, and those without cigarette-related disease.

Adolescent↗
PubMed1991

The effects of combining education and enforcement to reduce tobacco sales to minors. A study of four northern California communities.

OBJECTIVE: To examine the effects of a community education and law enforcement intervention on illegal tobacco sales to minors. DESIGN: A 2-year, before and after trial with retail stores as the unit of analysis. SETTING: Implementation occurred in four suburban California communities with populations of 25,000 to 100,000. PARTICIPANTS: All the retail stores in one intervention community and half the retail stores, randomly selected, in the other three intervention communities (n = 169) were visited by minors aged 14 to 16 years with the intent to purchase tobacco. INTERVENTION: Ongoing community and merchant education and four law enforcement operations were conducted. MAIN OUTCOME MEASURES: Over-the-counter and vending machine sales of tobacco to minors were the primary outcomes. RESULTS: Among a cohort of stores visited by minors at the pretest (n = 104) in June 1988, 71% sold tobacco over the counter and 92% sold tobacco through vending machines. At posttest 2 in May 1990, 24% sold tobacco over the counter and 93% sold tobacco through vending machines. Of the 31 stores issued citations, 16 were followed into the courts where the fines were dismissed or reduced. CONCLUSIONS: Education alone had a limited effect on reducing illegal tobacco sales to minors. It did promote community support for more aggressive enforcement strategies. Education plus enforcement decreased significantly over-the-counter sales; vending machine sales were unaffected by these interventions. The lack of support at the judicial level may temper the effectiveness of enforcement. Legislative remedies addressing judicial obstacles and vending machine sales are needed.

Adolescent↗
PubMed1991

Randomisation.

Explore the source record for details and available documents.

Bias↗
PubMed1991

Statistics in medical journals: developments in the 1980s.

This paper reviews changes in the use of statistics in medical journals during the 1980s. Aspects considered are research design, statistical analysis, the presentation of results, medical journal policy (including statistical refereeing), and the misuse of statistics. Despite some notable successes, the misuse of statistics in medical papers remains common.

Clinical Trials as Topic↗
PubMed1991

Obstacles to and future goals of ten comprehensive community health promotion projects.

Over 100 project staff, community coalition members, and other representatives from 10 comprehensive community health promotion projects in the western United States were surveyed two years into a three year funding cycle about: (1) the problems or obstacles they judged as preventing successful completion of their current goals and objectives, and (2) future goals and objectives they envisioned for their projects. The key issues confronting respondents were diverse, although issues around the process of implementing community health promotion programs were cited more frequently than issues related to the content of health promotion. When respondents were asked to prioritize Future Goals in the second survey, consensus across communities was obtained despite broad differences in the type of community surveyed and the health problem targeted. This study identifies the common organizational and community development problems faced by newly emerging community health promotion programs and has implications for other communities involved in designing, implementing, and evaluating community-wide health promotion programs.

Community Health Services↗
PubMed1991

c-erbB-2 protein overexpression in breast cancer is a risk factor in patients with involved and uninvolved lymph nodes.

The c-erbB-2 gene is overexpressed in about 20% of human breast cancers. Four hundred and eighty-three cases previously examined by immunohistochemical staining for c-erbB-2 expression were analysed to assess the risk associated with the elevated protein expression. Oncoprotein expression was correlated with increasing tumour grade but not with oestrogen receptor status, nodal involvement, tumour size or age. There was an increased risk of relapse and death associated with c-erbB-2 expression irrespective of nodal involvement. This marker thus appears to be a significant prognostic factor in the early as well as the late stages of breast cancer.

Adult↗
PubMed1991

Responsible alcohol service: a study of server, manager, and environmental impact.

A responsible alcohol-service training program was evaluated for its impact on changing beliefs, knowledge, and behavior in 97 servers and 43 managers and on changing establishment policies that encourage safer drinking environments. The training program had a significant impact on changing the beliefs and knowledge of both servers and managers. Observation 4 to 6 weeks after training showed no effects on server behavior, but there was a tendency toward more establishment policies compared with controls.

Accidents, Traffic↗