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Biomedical subjects

J Whitehead

Publications and source records attributed to J Whitehead.

At least 91 records · Page 5Linked to original sources
PubMed1985

The relationship between Wolfe's classification of mammograms, accepted breast cancer risk factors, and the incidence of breast cancer.

Data collected between 1973 and 1984 on 696 incident cases of breast cancer and 1,376 matched controls from four Breast Cancer Detection Demonstration Project clinics in the United States were used to assess the role of mammographic parenchymal pattern as a risk factor and its relationship with other, accepted, risk factors. The data confirm previous reports of the influence of benign breast biopsy, age at first live birth, family history of breast cancer, and duration of menstruation on the incidence of breast cancer. Height is also found to be an influential factor. Parenchymal pattern is found to be a risk factor with effects comparable in magnitude to the other factors studied. It operates separately from them, except for its relationship with height and weight. After adjustment for parenchymal pattern, weight is seen to have a significant effect on breast cancer incidence, and height is no longer needed in a model for risk. A model which simultaneously incorporates all of the risk factors considered, including parenchymal pattern, is presented. While these factors are of interest in the epidemiology of breast cancer, it is demonstrated that they are insufficient to allow reliable prediction of the disease in an individual woman.

Body Height↗
PubMed1985

A randomized trial of antihuman thymocyte globulin versus murine monoclonal antihuman T-cell antibodies as immunosuppressive therapy for aplastic anemia.

A prospective randomized trial was undertaken to compare the efficacy and toxicity of murine antihunman T-cell monoclonal antibody (mcAb) therapy to that of horse antihuman thymocyte globulin (ATG) in the treatment of severe aplastic anemia (AA). Patients were randomized into one of the two treatment groups as well as to receive or not receive androgens. Median duration of aplasia prior to treatment was 1.5 and 2.2 months for the mcAb and ATG groups, respectively. One of 12 patients who received mcAb therapy had a partial response, whereas four of 13 patients receiving ATG had a complete or partial response. Of the 11 patients who failed mcAb treatment, six were subsequently treated with ATG and two improved. Ten of 13 patients who received ATG are surviving compared with seven of 12 patients who received mcAb. Toxicity of mcAb therapy was less than that of ATG. Future studies are needed to determine whether mcAbs known to be immunosuppressive are of benefit as therapy for patients with AA.

Adolescent↗
PubMed1985

Designing phase II studies in the context of a programme of clinical research.

Conventional statistical determinations of sample size in phase II studies typically lead to sample sizes of the order of 25 (Schoenfeld, 1980, International Journal of Radiation Oncology, Biology and Physics 6, 371-374). When the development of new treatments is proceeding rapidly relative to the recruitment of suitable patients, such requirements can prove to be too demanding. As a result, either sample sizes are reduced by a rather arbitrary weakening of the risk specifications, or certain new treatments go untested. In this paper, the phase II testing of a number of treatments will be considered as a single study which has the objective of identifying the most promising treatment for phase III investigation. It is seen to be advantageous to test more treatments, with fewer subjects receiving each, than the conventional methods would allow.

Biometry↗
PubMed1984

Pulmonary bronchoalveolar cell and protein kinetics in dogs given total-body irradiation, autologous marrow grafts, and methotrexate.

Patients receiving allogeneic marrow transplantation for hematologic malignancies commonly are conditioned with total body irradiation (TBI) and given methotrexate (MTX) in an attempt to prevent graft-versus-host disease. To study the effects of TBI with or without MTX on bronchoalveolar cells and proteins, we performed sequential bronchoalveolar lavages in dogs before and after irradiation. Ten dogs received 9 Gy TBI followed by autologous marrow grafts. Six dogs were given no additional treatment and four also received MTX at 0.4 mg/kg on days 1, 3, 6, and 11- and then weekly until day 100. TBI alone resulted in a significant decrease in alveolar macrophages and lymphocytes with recovery after day 30. The addition of MTX resulted in a more profound and prolonged decrease in alveolar macrophages and lymphocytes. The addition of MTX was also associated with a significant increase in alveolar granulocytes with a concomitant rise in lavage protein content in one animal. Lavage fluid IgA levels remained constant. We conclude that the irradiation and chemotherapy used in marrow transplantation has significant pulmonary effects and may contribute to the pulmonary complications following marrow transplantation.

Animals↗
PubMed1983

An outbreak of Mycobacterium bovis infection in cats in an animal house.

An outbreak of tuberculosis due to Mycobacterium bovis in cats in an animal house was investigated. It was concluded that the index case was infected by ingestion of contaminated meat obtained from a knackery and that some of the other cases were infected by inhalation of tubercle bacilli shed from a discharging sinus in the index case. A possum was also infected and a research worker apparently received a significant challenge.

Animals↗
PubMed1983

Group sequential clinical trials with triangular continuation regions.

In this paper a new class of group sequential procedures for clinical trials is introduced, and the use of these procedures is illustrated by reference to a recently completed comparative study. In a group sequential trial the decision to stop or to continue is made at regular intervals throughout the trial, but not as frequently as after every patient response. This more practical formulation retains most of the advantages of sequential analysis, particularly the economy in sample size. Comparisons are made with group sequential designs derived from the repeated significance test.

Anesthetics↗
PubMed1978

Variation in energy intake of aldolescent schoolgirls.

Twenty-four 16 to 17 year-old grammar school girls completed daily dietary histories (for eight weeks), and recorded details of mood, appetite and menstrual cycle. Marked daily variation in energy intakes was noted: on average an individual's highest daily intake was nearly four times her lowest intake, one subject having a nearly tenfold difference. Fluctuations were not related to mood, suggesting that this has less influence on dietary patterns than is generally supposed. While sitting examinations, energy intake was reduced by an average of 11.85%. It was not significantly changed during a field trip or by menstruation. This study suggests that dietary patterns previously considered to be abnormal or unusual are exhibited by and firmly entrenched in normal school girls.

Adolescent↗
PubMed1977

Biology of colon cancer: an overview.

The altered growth characteristics of neoplastic cells have recently been associated with changes in membrane glycoproteins present on the cell surface. Since the carbohydrate moieties of surface membrane glycoproteins are asymmetrically located on the external cell surface, these glycoconjugates are likely candidates for providing cell surfaces with many of their biological properties. Using specific external cell surface labeling techniques, we have broadened our investigation of tumor cell surface glycoconjugates to include studies on cultured human epithelial cells from fetal intestine and from colonic carcinoma. We have isolated by affinity chromatography and gel filtration and integral membrane glycoprotein, termed Galactoprotein I, from a cultured human colonic adenocarcinoma cell line, which appears to be identical in many respects to CEA. Further examination of cell surface glycoproteins regarding quantitative and qualitative alterations and topographical redistribution should provide an insight into the biological aspects of tumor development.

Carcinoma↗
PubMed1971

Geriatric practice.

Explore the source record for details and available documents.

Abdominal Neoplasms↗
PubMedDate not supplied

A unified theory for sequential clinical trials.

The theory underlying sequential clinical trials is now well developed, and the methodology is increasingly being implemented in practice, both by the pharmaceutical industry and in the public sector. The consequences of conducting interim analyses for frequentist interpretations of data are now well understood. A large number of approaches are available for the calculation of stopping boundaries and for the eventual terminal analysis. In this paper, the principles of the design and analysis of sequential clinical trials will be presented. Existing methods will be reviewed, and their relationships with the general principles will be clarified. Controversies and gaps within the methodology will be highlighted. It is intended that presentation of the subject as a single unified theory will allow the few essential underlying features to be better appreciated.

Clinical Trials, Phase III as Topic↗