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Biomedical subjects

M Weeks

Publications and source records attributed to M Weeks.

At least 19 recordsLinked to original sources
PubMed2003

Unintended consequences of using an oral HIV test on HIV knowledge.

This study assessed the effects of oral HIV testing on the belief that HIV can be transmitted in saliva and on overall AIDS knowledge. A sample of current or former street drug users (N = 155) was recruited to complete a survey of HIV risk behaviour at two points in time. The survey included three items that assessed beliefs in the possible transmission of HIV through saliva. Among the 80 participants who received oral HIV testing at baseline, accuracy on the three saliva items decreased at follow-up and, among the 75 participants who did not receive oral HIV testing, accuracy on these items increased at follow-up. This pattern of change was statistically significant. Oral HIV testing has been a significant advance. However, unintended effects may include increased belief in the transmission of HIV through saliva. This problematic outcome suggests the importance of enhanced HIV counselling among participants in oral HIV testing.

Female↗
PubMed2001

"War stories": AIDS prevention and the street narratives of drug users.

The day-to-day discourse of illicit drug users is replete with stylized narratives of street experience. These "war stories," as they are popularly known, are shared among drug users as they hustle for money, purchase drugs, get high, and hang out in diverse street locations. Drug-user narratives, which describe complex adventures and grave suffering, are primary ethnographic sources of information about patterns of drug consumption and risk behaviors. Importantly, in the time of AIDS, street narratives provide a much-needed window on the generally hidden lives of socially marginalized street drug users. As part of an effort to put the analysis of drug-user war stories to use in HIV prevention, in this article the authors analyze a corpus of street narratives told to members of an HIV-prevention research team in Hartford, Connecticut.

Adaptation, Psychological↗
PubMed2000

Evaluating the predictive value of osteoarthritis diagnoses in an administrative database.

OBJECTIVE: To assess the positive and negative predictive values of osteoarthritis (OA) diagnoses contained in an administrative database. METHODS: We identified all members (> or =18 years of age) of a Massachusetts health maintenance organization with documentation of at least one health care encounter associated with an OA diagnosis during the period 1994-1996. From this population, we randomly selected 350 subjects. In addition, we randomly selected 250 enrollees (proportionally by the age and sex of the 350 subjects) who did not have a health care encounter associated with an OA diagnosis. Trained nurse reviewers abstracted OA-related clinical, laboratory, and radiologic data from the medical records of both study groups (all but 1 chart was available for review). Pairs of physician reviewers evaluated the abstracted information for both groups of subjects and rated the evidence for the presence of OA according to 3 levels: definite, possible, and unlikely. RESULTS: Among the group of patients with an administrative diagnosis of OA, 215 (62%) were rated as having definite OA, 36 (10%) possible OA, and 98 (28%) unlikely OA, according to information contained in the medical record. The positive predictive value of an OA diagnosis was 62%. In those without an administrative OA diagnosis, 44 (18%) were assigned a rating of definite OA. The negative predictive value of the absence of an administrative OA diagnosis was 78%. CONCLUSION: Use of administrative data in epidemiologic and health services research on OA may lead to both case misclassification and under ascertainment.

Aged↗
PubMed1989

CBXC: a set of recombinant inbred strains between CBA/Ca and BALB/c.

A new set of nine recombinant inbred strains designated CBXC-1 to CBXC-9 has been developed from a cross between CBA/Ca female and BALB/c male mice. All of the strains have been brother x sister mated for more than 20 generations, and have been characterized at eight electrophoretic, one immunological and two coat colour loci at which the progenitor strains differ. This set of strains should be useful in investigating the genetics of any characters which differ between the two progenitor strains.

Animal Husbandry↗
PubMed1987

Modulation of human tumor antigen expression.

With membrane-enriched fractions prepared from human metastatic breast tissue used as immunogen, a group of monoclonal antibodies (MAbs) were generated that recognized several distinct antigens on breast and other carcinomas. The antibodies were found to react with established human tumor cells in culture as well as in immunohistochemical protocols using sections of primary and metastatic lesions. One MAb, B72.3, demonstrated a high degree of selective reactivity for human carcinomas in that no reactivity was found with a large number of different normal tissues. These MAbs were used to demonstrate the heterogeneity of expression of the tumor antigens as well as the intrinsic cellular factors (i.e., cell-cycle kinetics and clonal variability) that modulate their expression. Additional studies showed that recombinant human leukocyte interferon can act as a potent regulator of surface antigen expression on human carcinoma cells. Analysis of these cells by radioimmunoassay or flow cytometry revealed that interferon treatment resulted in a higher percentage of the cell population that bind the MAb to the surface antigen. Furthermore, interferon treatment also increases the level of expression for particular tumor antigen throughout the tumor cell population. Experimental models were also developed to investigate the active localization of a radiolabeled MAb by a human tumor xenograft in athymic mice. The results demonstrate active uptake of an 125I-B6.2 by a transplantable human breast tumor that expressed significant quantities of the B6.2-reactive 90 kD tumor antigen. In contrast, a human melanoma cell line grown as a solid, subcutaneous tumor in athymic mice did not localize the labeled B6.2 and does not express the associated 90 kD antigen. We report the generation and characterization of anti-breast carcinoma MAbs. These immunologic probes were used to study relevant breast tumor antigens, the factors that influence their level of expression, and the ability of human tumors grown in athymic mice to localize radiolabeled antibodies.

Animals↗
PubMed1984

Monoclonal antibodies to breast cancer-associated antigens as potential reagents in the management of breast cancer.

Monoclonal antibodies reactive with the surface of human breast carcinoma cells have been generated and characterized. The immunogens used were membrane-enriched fractions of metastatic carcinoma lesions. The various monoclonals were shown to react with previously known as well as with novel tumor-associated antigens (TAAs). The most specific of the latter group is monoclonal B72.3, which is reactive with a 220,000 to 400,000 high-molecular-weight glycoprotein complex found in 50% of human mammary carcinomas and 80% of human colon carcinomas. Monoclonal antibody B6.2, which recognizes a 90,000-d glycoprotein, was radiolabeled and shown to efficiently localize human carcinoma transplants in athymic mice via gamma imaging without the use of second antibody or background subtraction manipulations. F(ab')2 and Fab' fragments were shown to be more efficient for tumor localization than intact immunoglobulin. Whereas the phenomenon of antigenic heterogeneity of tumor cell populations has long been known to exist, this phenomenon was also shown to manifest itself as antigenic modulation, in which specific TAAs can modulate their expression on the cell surface concurrent with different phases of the cell cycle. A phenomenon known as antigen evolution, in which a specific cloned tumor cell population can gradually drift in antigenic phenotype, has also been demonstrated. Recombinant interferon has been employed to (1) enhance the expression of specific TAAs on the surface of tumor cells already expressing the antigen; and (2) induce the expression of specific TAAs on the surface of carcinoma cells not previously expressing the antigen. The clinical implications of such phenomena in gamma scanning for the detection of tumor masses and for tumor immunotherapy are discussed. Methods for circumvention of problems inherent in the clinical use of monoclonal antibodies are also addressed.

Animals↗
PubMed1981

Task difficulty and aberrant behavior in severely handicapped students.

The influence of task difficulty on aberrant behavior was investigated with three severely handicapped students. Noticeably higher rates of problem behavior occurred in demand compared to no-demand conditions. In addition, there were higher rates of problem behaviors on difficult versus easy tasks. Both these findings were validated with visual discrimination and perceptual motor tasks. An errorless learning procedure effectively minimized errors and aberrant behavior in visual discrimination tasks but not in perceptual motor tasks. It was conceptualized that aberrant behavior was maintained by negative reinforcement contingencies. Difficult tasks were aversive to the children, who emitted aberrant responses to escape or avoid such tasks. By contrast, conditions in which no demands were made, easy tasks, and, in visual discrimination learning, errorless tasks, were less aversive and resulted in little or no problem behavior. Implications for reducing maladaptive behaviors through curricular modifications are discussed and contrasted to more traditional consequence manipulation approaches.

Achievement↗