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Biomedical subjects

R M Rippey

Publications and source records attributed to R M Rippey.

At least 19 recordsLinked to original sources

A computerized cancer information system.

Cancer information was made available via a computer to patients visiting the University of Connecticut Dental Clinics. The computer program was menu driven. An option allowed users to leave messages for the system owners. The computer program generated a log of usage, user comments and items chosen. The user could choose from the following topics: (1) general information on cancer; (2) diet, nutrition and cancer; (3) smoking; (4) the environment, occupations and cancer; and (5) physical checkups. An option to leave a message for the system operators was the option chosen least. Analysis of the usage log shows that the system was used substantially while people were waiting in the clinic and that at least three or four individuals used the system every clinic day. Such information systems can provide important information to the public. The novelty of the system and the lack of supervision did not deter public use.

Connecticut↗

Methods used by urban, low-income minorities to care for their arthritis.

The purpose of this study is to describe the current treatment methods minorities use and believe are effective in relieving the pain and discomfort of arthritis. One hundred sixty subjects from two urban, low-income minority communities reported to case finders that they had some form of arthritis. Subsequently they were interviewed and examined by a rheumatologist. Sixty-six percent were black, and 34% were Hispanic. The study found that 83% had some type of rheumatic disease. Differences existed between the black and Hispanic samples in age, rheumatic disease distribution, and methods of care. The majority of black respondents were older, with a frequent diagnoses of osteoarthritis, compared to the Hispanics, who reported fibrositis as their dominant rheumatic problem. An array of conventional and nonconventional therapies were used by both groups to care for their arthritis. Prayer (92%), equipment (70%), and heat (33%) were reported as "most helpful" for the blacks. Hispanics reported prayer (50%), heat (40%), and topical ointments as "most helpful." In order to communicate and provide optimal care to patients from divergent cultural backgrounds, it is important to understand both likenesses and differences, and to be sensitive to the patient's belief system and health care practices.

Adult↗

Unfavourable outcomes of drug therapy--subjective probability versus confidence intervals.

To investigate how individual predictions compare with confidence intervals, we asked 50 medical residents and 28 graduate students with biostatistics training to estimate unfavourable outcomes of drug therapy (therapeutic failures and side-effects) in groups of 10 and 20 patients. The predictions made by physicians and graduate students were similar for both sample sizes and types of outcome. The majority (58%) of estimates were greater than the upper limit of the 95% confidence interval, a bias that may hamper the correct interpretation of therapeutic risks in medical decision-making.

Adult↗

Computer-based patient education for older persons with osteoarthritis.

A program of 8 lessons on various aspects of osteoarthritis (OA), its treatment, and patient self-care was prepared on an Apple IIc computer. The courses were then field-tested and evaluated by 72 older (age range 52-88) OA patients in community centers for senior citizens. Statistical analysis of the findings showed significant increases in knowledge and significant self-reported, beneficial behavior changes, including increased exercise, use of heat, and rest. Our findings demonstrate that older persons can use the computer to learn to cope with OA when a thoughtfully planned program is made available in a community setting.

Aged↗

Low level X-radiation effects on carcinogenesis by 7,12-dimethylbenz(a)anthracene in Syrian hamster cheek pouch epithelium: acute vs fractionated radiation dose studies.

Studies examined the effects of acute and fractionated low to moderate level X-ray exposures on hamster cheek pouch carcinogenesis in vivo by 7,12-dimethylbenz(a)anthracene (DMBA). Animals were grouped by treatment as follows: acute doses of 0.85-3.40 Gy X rays; 17 once weekly doses of 0.01-0.20 Gy X rays (fractionated radiation); topical DMBA for 10 weeks; DMBA plus fractionated radiation starting together; DMBA plus acute radiation in Week 1 or 10 of DMBA treatments; and sham irradiation, DMBA vehicle, or anesthesia controls. After 44 weeks, hamsters were sacrificed, and their cheek pouches were excised, serially sectioned, and examined by light microscopy for histopathology. No histologic changes were observed in radiation-only hamsters. Carcinoma incidences in DMBA-only groups ranged from 45 to 60%. Carcinoma incidences were greater in groups receiving DMBA plus fractionated radiation than in groups receiving either acute radiation + DMBA or DMBA alone. Carcinoma incidences in acute radiation plus DMBA groups were lower than those in DMBA-only groups. These results suggest complex interactions between radiation and DMBA, perhaps with radiogenic cell killing being a principal factor in acute radiation + DMBA groups, and reciprocal additive or synergistic effects of radiation and DMBA on cancer induction and manifestation in fractionated radiation + DMBA groups.

9,10-Dimethyl-1,2-benzanthracene↗

Premature conclusions in diagnostic reasoning.

The purpose of the study reported here was to explore the characteristics of premature diagnostic conclusions in a group of physicians, medical students, and residents. When the subjects were asked to construct complete, precise problem lists from three case abstracts, premature closure occurred frequently, it could be recognized with good interrater reliability, and it seemed to appear with equal frequency regardless of the level of training.

Clinical Competence↗

Low-level X-radiation effects on functional vascular changes in Syrian hamster cheek pouch epithelium during hydrocarbon carcinogenesis.

Effects of repeated low-level X radiation on functional microvascular changes in hamster cheek pouch epithelium during and following carcinogenesis by 7,12-dimethylbenz[a]anthracene (DMBA) were studied. Prior studies showed enhancement of such carcinogenesis by repeated 20 rad head and neck X-radiation exposures, and it was proposed that one possible mechanism was radiogenic alteration of the functional microvasculature in a manner which favored subsequent tumor development. Hamsters were treated with either radiation, DMBA, radiation + DMBA, or no treatment. Animals were sacrificed at 3-week intervals from 0 to 39 weeks after treatments began. Pouch vascular volume and permeability changes were studied by fractional distributions of radiotracers and were analyzed by a variety of statistical methods which explored the vascular parameters, treatment types, elapsed time, presence of the carcinogen, and histopathologic changes. All treatments resulted in significant changes in vascular volume with time, while only DMBA treatments alone resulted in significant changes in vascular permeability with time. Prior to the appearances of frank neoplasms, volumetric changes in DMBA only and radiation only groups were similar, while volume changes in DMBA + radiation groups increased slowly to a peak later than in other groups and then declined steadily to levels similar to the radiation only group. As in prior studies, there were significant vascular volume differences between DMBA and DMBA + radiation groups of tumor-bearing cheek pouches. DMBA maxima were significantly higher than those of DMBA + radiation. Radiation significantly affected DMBA-associated vascular volume and permeability changes during carcinogenesis. Several possible explanations for the relationship of these changes to the enhancement of DMBA carcinogenesis include: radiation blocking normal capillary proliferative and/or dilatory responses to inflammation secondary to neoplastic changes; radiation-induced focal increases in the pericapillary connective tissue histohematic barrier, stimulating angiogenesis but reducing nutrient diffusion; radiation exposures sensitizing vascular endothelium to subsequent angiogenic stimulation from premalignant tissues; DMBA vascular and epithelial effects partially or completely blocking radiation effects on epithelial and/or endothelial cells; and radiation damage to vessel walls partially or fully inhibiting normal physiologic mechanisms of repairing DMBA damage to the vessels.

9,10-Dimethyl-1,2-benzanthracene↗

Possible mechanistic roles of anatomical and functional vascular changes in rat urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine.

Anatomical and functional vascular changes during rat urinary bladder carcinogenesis were studied by scanning electron microscopy of vascular casts, transmission electron microscopy of bladder capillaries, and fractional distributions of 51Cr-erythrocytes, 125I-human serum albumin, and 86RbCl which were used to determine vascular volume, permeability, and perfusion. Histopathological changes and focal capillary changes in vascular casts were measured quantitatively by an image analyzer. Male Wistar rats received 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 8 weeks and were then maintained on tap water without BBN for an additional 32 weeks. Simple hyperplasia was first seen at Week 2. The percentage of the area of hyperplastic epithelium increased to about 95% by Week 8 and then decreased to 4 to 6% at Weeks 20 or 40. Papillary or nodular hyperplasia was first seen at Week 6. The percentage of the area of papillary or nodular hyperplasia increased with time to 31.0% at Week 40. Papillary transitional-cell carcinomas were found from Week 20, increasing with time, and their incidence was 100% after Week 35. Vascular cast diameters of normal-looking capillaries were larger during than after BBN treatment. Type 3 vascular proliferations were found beneath papillary or nodular hyperplasia and cancer. Capillaries beneath simple hyperplasia and type 3 capillaries beneath capillary or nodular hyperplasia and cancers were fenestrated and dilated. Changes in vascular volume were independent of changes in permeability and perfusion. Best-fit curve analyses showed the maximum vascular volume at 8 weeks and minimum at 25 weeks, and the permeability maxima at 4 and 25 weeks with minima at 15 and 32 weeks. While 86Rb values correlated 125I values (r = 0.58), they were unstable in intermediate time periods. Changes of vascular volume were coincident initially with increased areas of dilated capillaries beneath simple hyperplasia and later with areas of type 3 capillary proliferation beneath papillary or nodular hyperplasia and cancer. Changes of vascular permeability were related to inflammation indices throughout the study. Increases in permeability were coincident with fenestrated capillaries beneath simple hyperplasia in early stages, and subsequently with fenestrated type 3 capillaries beneath papillary or nodular hyperplasia and cancer. BBN appears to cause alterations in vascular volume via induction of capillary dilation and also possibly by enhancing the responsiveness of host endothelium to angiogenic stimulation from neoplastic or preneoplastic tissues.

Analysis of Variance↗

Anatomical and functional vascular changes in hamster cheek pouch during carcinogenesis induced by 7, 12-dimethylbenz(a)anthracene.

Anatomical and functional vascular changes during hamster cheek pouch carcinogenesis were studied by light microscopy; scanning electron microscopy of vascular casts; transmission electron microscopy of cheek pouch capillaries; and fractional distributions of 51Cr-erythrocytes, 125I-human serum albumin, and 86RbCI which were used to determine vascular volume, permeability, and perfusion. Histopathological changes and focal capillary changes in vascular casts were measured quantitatively by an image analyzer. Male Syrian hamsters received 0.5% 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil for 11 weeks and were sacrificed at periodic intervals from 2 to 20 weeks after initial treatment. Simple hyperplasia was first seen at Week 1. The area of hyperplastic epithelium, expressed as percentage, increased to about 60% by Week 8 and then decreased to 30% at Week 20. Dysplastic foci were first seen at Week 2. The percentage of the area of dysplasia increased with time to 41% at Week 20. Squamous cell carcinomas occurred from Week 10, increased with time, and were found in all animals at Week 20. Vascular cast diameters of normal-looking capillaries were larger during than after DMBA treatment. Type 3 vascular proliferations were found beneath dysplasia and cancer. Capillaries beneath simple hyperplasia and type 3 capillaries beneath dysplasia and cancers were dilated but not fenestrated. Changes in vascular volume were independent of changes in permeability and perfusion and also occurred in contralateral untreated pouches of treated animals. While 86Rb values initially correlated with 125I values, the 86Rb values were unstable in intermediate and later time periods. Changes of vascular volume were accompanied initially by the presence of DMBA and were coincident with increased areas of dilated capillaries beneath simple hyperplasia and later with areas of type 3 capillary proliferation beneath dysplasia and cancer. Changes of vascular permeability were related to inflammation indices throughout the study. DMBA may lastingly alter capillary endothelium in a manner which allows or aids in its subsequent dilatory and proliferative responses to angiogenic stimulation from malignant tumors, and possibly from premalignant or malignantly transformed cells.

9,10-Dimethyl-1,2-benzanthracene↗

Knowledge, realism, and diagnostic reasoning in a physical diagnosis course.

Two 20-item tests and a case problem were administered to 83 students in a physical diagnosis course. One test contained items related to the content of the case problem, and the other items related to the balance of the course content. Confidence scoring procedures yielded scores of both knowledge and realism on the two tests. The case problem determined the subject's ability to integrate clinical data into an accurate list of diagnoses and yielded scores reflecting incomplete assembly of clues into diagnoses (incomplete synthesis) and unjustified conclusions (premature closure). Reliability of the confidence-scored tests was significantly greater than the reliability on the same items scored as a single correct answer. Knowledge improvement scores on both tests (relevant and nonrelevant knowledge) were significantly correlated with errors of incomplete synthesis. The realism score correlated significantly with premature closures but only on the test where the item content was relevant to the case problem.

Curriculum↗

A study of the University of Connecticut's criteria for admission into medical school.

Scores on nineteen pre-admission and post-admission performance variables for four classes of medical students were analysed using canonical correlation and regression methods. Detailed interviews with 138 clinical preceptors were included among the criterion variables. National Board Part I scores could be predicted readily from conventional data such as Medical College Admission Test scores and grade point average. However, these same predictors generally correlated negatively with measures of clinical performance. Evidence supports pre-admission interviews and careful analysis of letters of recommendation as useful predictors of the clinical performance variables.

Connecticut↗