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Biomedical subjects

D L Bronson

Publications and source records attributed to D L Bronson.

52 records · Page 3Linked to original sources
PubMed1977

Properties of cell lines established from transitional cell cancers of the human urinary tract.

Characterization studies have been carried out on eight cell lines (253J, 192B, 639V, 647V, 486P, 575A,743E, and 751G) established from transitional cell cancers of the human urinary tract. Although subtle morphological differences exist among individual lines, each has an epithelial morphology and exhibits multilayering. The doubling times for the cells range from 20 to 56 hr, and at least a 1-to-3 split can be achieved when they are subcultured every 4th day. Karyotypic analysis revealed a hyperdiploid stemline for each cell line, and presence of a Y chromosome was confirmed by Q banding in five of the lines. The tumorigenic nature of the cell lines was demonstrated by their production of tumors in hamsters and confirmed by colony formation in agar. The transitional cell cancer lines were shown to be free of Mycoplasma, and their glucose-6-phosphate dehydrogenase mobility patterns and their Karyotypes prove that they are not HeLa cells.

Animals↗
PubMed1976

A comparison of four methods used to concentrate Rous sarcoma virus from tissue culture fluids.

Three methods of pelleting, pelleting followed by Pronase treatment, polyethylene glycol (PEG)-Pronase, and diaflo ultrafiltration (diafiltration) were used to concentrate RSV(RAV-1) from tissue culture fluids. Sucrose-gradient fractions containing virus preparations which had been concentrated by diafiltration or pelleting were heavily contaminated with amorphous debris. This debris was not present in similar, gradient-purified preparations that had been concentrated by the PEG-Pronase or pellet-Pronase methods. Maximum recovery of radiolabelled virus particles and virion-associated RNA-dependent DNA polymerase activity was obtained in gradient fractions containing virus concentrates prepared by the pellet-Pronase and PEG-Pronase methods. Although there were slight differences in recovery by these two methods, the advantages of the PEG-Pronase method make it the preferred method, especially when large volumes of tissue culture fluids are used.

Avian Sarcoma Viruses↗
PubMed1976

Biochemical characteristics of rat C-type virus WF-1.

The non-oncogenic rat C-type virus WF-1, isolated from a Wistar-Furth rat embryo cell line, was characterized biochemically. The purified virus has a buoyant density of 1.15 to 1.16 g/cm3 in sucrose, RNA-dependent DNA polymerase (reverse transcriptase) activity, and RNA with a sedimentation coefficient of 62 to 68 S. The viral RNA is single-stranded, and, upon treatment with heat, yields components with sedimentation coefficients of 36 S, 18 to 20 S, and 4 to 12 S.

Animals↗
PubMed1976

In vitro cultivation of epithelial cells derived from tumors of the human urinary tract.

Finely minced explants from 54 TCC2 of the human urinary tract were cultured in vitro in an attempt to establish cell lines. Cells with epithelial morphology grew out from 48 tumor explants, and long-term cell cultures were established from 10. Six of the cell cultures have been maintained for over 18 months with 50 to 70 transfers and, therefore, are considered permanent cell lines. The epithelial cells in the established cultures are small, exhibit rapid doubling time, and show multilayering. The cells were examined both microscopically and by cultivation techniques, and they were found to be free from contaminating microorganisms, including Mycoplasma. The established cultures grow rapidly in roller bottles and, therefore, can be produced in large quantities. These cells also remain viable after being stored for 3 years in liquid nitrogen.

Carcinoma, Transitional Cell↗
PubMed1975

Concentration of Rous sarcoma virus from tissue culture fluids with polyethylene glycol.

Concentration of Rous sarcoma virus from tissue culture fluids with polyethylene glycol, with and without NaCl or dextran sulfate, resulted in significant and highly variable losses caused by entrapment of virus particles in proteinaceous debris. Treatment of concentrated preparations with Pronase greatly enhanced the recovery of virions. Maximum recovery of virus particles was obtained by the addition of 8% polyethylene glycol and 0.4 M NaCl to tissue culture fluids, followed by Pronase treatment of the concentrated virus preparations.

Animals↗
PubMedDate not supplied

The impact of shared medical records on smoking awareness and behavior in ambulatory care.

In a randomized controlled trial of sharing medical records with ambulatory adults as part of periodic health examinations, 193 patients (experimental group; 37 smokers) received copies of their medical records while 208 patients (control group; 50 smokers) did not. Awareness of smoking as a health problem and smoking behavior were assessed two weeks and six months later. At two weeks, 46% of experimental group smokers indicated that smoking was a major health problem, compared with 21% of the control group (p less than 0.02), and 43% of the experimental group had quit or reduced smoking, compared with 20% of the control group (p less than 0.02). At six months smoking problem awareness was not significantly different (33% experimental group vs. 14% control group, p = NS), but 65% of the experimental group had quit or reduced compared with 29% of the control group (p less than 0.04). Sharing medical records with smokers after periodic health examinations is effective in enhancing patient awareness of smoking as a health problem and beginning the process of changing smoking behavior.

Female↗
PubMedDate not supplied

Establishing a quality improvement process for identification of psychosocial problems in a primary care practice.

OBJECTIVES: A quality improvement process that will significantly increase the rate of identification of psychosocial problems through routine use of case-finding instruments can be established in a general medicine practice. DESIGN: Two groups of patient examination reports written by physicians were retrospectively compared with the patients' responses on the case-finding database instrument. The samples were obtained by sequential selection in four time periods. SETTING AND PATIENTS: The study occurred in a university general internal medicine practice that utilizes the problem-oriented record. The patients studied were seen for first-time comprehensive examinations designed to identify all important health problems, including psychosocial problems. INTERVENTION: The authors compared performances of the physicians in identification of psychosocial problems before and after the intervention, which consisted of a pilot study audit of psychosocial problem identification, establishment of standards for interpretation of the case-finding instrument, design of a flow sheet to make case-finding data clearly available to the physician at each comprehensive examination, and feedback of physician performance according to practice-adopted standards for identification of psychosocial problems. MEASUREMENT: The result of the intervention was an increase in psychosocial problem identification from 67% to 90% of problems present, p less than 0.05 by chi-square distribution; or a decrease from 33% to 10% in psychosocial problems missed by the physicians. CONCLUSION: The quality improvement process for identification of psychosocial problems described in this report significantly increased the rate of identification of psychosocial problems by general internists.

Adolescent↗
PubMedDate not supplied

Preoperative risk factors for postoperative delirium.

The objective of this article was to estimate the incidence of delirium in a sample of patients undergoing elective surgery and to identify the preoperative factors most closely associated with developing this complication. Consecutive patients (n=500) underwent a full preoperative medical evaluation including assessment of cognitive and functional status. Daily evaluation on postoperative days 1 through 4 included medical record review and direct standardized patient interviews. Logistic regression was used to explore the associations between preoperative factors and postoperative delirium. Delirium was detected in 57 (11.4%) patients. Univariate factors associated with delirium included age> or =70 years (RR=3.1 [1.75,5.55]), preexisting cognitive impairment (RR=3.1 [1.73, 5.43]), greater preoperative functional limitations (RR=1.57 [1.27, 1.94]), and a history of prior delirium (RR 4.1 [1.98 to 8.27]. Adjusting for other factors, previous delirium (OR=4.08 [1.85, 9.0]), age> or =70 years (OR=3.2 [1.6, 6.0], and preexisting cognitive impairment (OR=2.16 [1.15, 4.0] remained predictive of delirium. Patients' perceptions that alcohol had affected their health (OR=6.53 [1.58 to 28.1]) and use of narcotic analgesics just prior to admission (OR=2.7 [1.37 to 5.3]) were also significantly associated with delirium postoperatively. Several easily obtained preoperative clinical factors can be used to identify patients at risk for postoperative delirium. This approach, when combined with specialized delirium teams using established guidelines, may be more effective in targeting patients at risk, thus reducing the number of episodes and days of delirium.

Age Factors↗
PubMedDate not supplied

Evaluating cardiac risk in noncardiac surgery patients.

The cornerstones of the evaluation of cardiac risk in patients undergoing noncardiac surgery remain a thorough history and physical examination, and a resting electrocardiogram. However, new techniques to assess cardiac function allow more complete evaluation of high-risk patients.

Algorithms↗
PubMedDate not supplied

Recruitment in a primary care trial on smoking cessation.

The purpose of this study was to describe and compare the rates of recruitment during a randomized clinical trial on smoking cessation in two primary care practices. One site was a five-physician private family practice setting with about 15,000 patients. During 34 days, 576 patients were screened, of whom 22% were smokers. Among the smokers screened, 54% consented, 33% refused consent, and 13% were called in too early to consent. The other site was a six-physician academic medical practice with about 16,000 patients. During 53 days, 1,692 subjects were screened, of whom 16.2% were smokers. Among the smokers, 19% consented, 81% refused consent, and none were called in early. The enrollment of smokers was 3.3 times greater in the private practice than the academic practice. At the first site, study personnel screened 26.6 subjects per day, whereas the practice receptionist screened only 13.4 subjects per day (P less than .01). A randomized trial of having subjects read the informed consent versus having study personnel read it to them showed no differences in recruitment. The data suggest that private practices may have greater potential for subject recruitment than academic sites, that using study personnel improves recruitment, and that having study personnel actively involved in informed consent does not improve recruitment.

Adult↗