SEARCH · Search PubMed

Results for “Pretesting”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources

PubMed2004

When sporadic disease is not sporadic: the potential for genetic etiology.

BACKGROUND: Approximately 2% of Alzheimer disease cases and 10% to 15% of prion disease cases are due to mutations in autosomal dominant genes. Mutations have been found in patients without family histories of neurological disease. OBJECTIVES: To emphasize the need for consideration of a genetic etiology of prion disease and early-onset Alzheimer disease, regardless of the absence of a significant family history, as well as the need for pretest genetic counseling of all patients or their families. DESIGN: Three case reports. PATIENTS AND RESULTS: Patient 1, a 53-year-old man with possible Creutzfeldt-Jakob disease, was enrolled in a research study that included sequencing of the prion protein gene. Although there was no family history of neurological disease, an E200K mutation was found. This unexpected result caused the family significant distress. Patient 2, a 55-year-old woman with biopsy-proven Creutzfeldt-Jakob disease, participated in a prion disease research study. Her family was counseled about the possibility of hereditary Creutzfeldt-Jakob disease, despite the lack of family history. After assessing the ramifications, the family decided not to learn about the patient's genetic test results. Patient 3 was a 54-year-old man with a 6-year history of memory loss. A diagnosis of probable Alzheimer disease was given, and the patient and his family were counseled on the availability of presenilin 1 testing, although there was no known family history of dementia. The family agreed to testing, and a presenilin 1 mutation was identified. CONCLUSIONS: Certain neurodegenerative diseases may have a genetic etiology, despite the lack of a positive family history. Revealing a newly discovered hereditary cause of Creutzfeldt-Jakob disease or Alzheimer disease can have a profound effect on families. Pretest counseling on genetic issues is essential to better prepare families and to allow them to make an informed choice about learning genetic test results.

Alzheimer Disease↗

PubMed1998

To teach is to learn twice. Resident teachers learn more.

OBJECTIVES: To describe the formal teaching activities of pediatric residents and to assess how the act of formal teaching affects residents' acquisition and retention of knowledge. DESIGN AND METHODS: Randomized controlled trial. Forty-three pediatric residents in a university-based program were surveyed about their teaching activities, given a pretest on a predetermined topic (oral rehydration), then randomly assigned to either teach (n = 18) or listen to (n = 25) a 30-minute lecture on that topic; 6 to 8 weeks later they completed a posttest. The difference between [retest and posttest scores was calculated for each resident as an index of knowledge acquisition. RESULTS: The mean number of resident teaching events per year was 3.5 for interns (n = 16), 2.9 for junior residents (n = 11), and 6.9 for senior residents (n = 16). Self-reported comfort with the teaching role, ability to hold a group's attention, and desire to teach were similar across year of training. Prior to randomization, teachers (experimental group) reported less interest in oral rehydration that did listeners (control group) (P < .03). However, knowledge acquisition was significantly greater for teachers than for listeners (posttest score minus pretest score [mean +/- SD], 6.1 +/- 4.2 vs 3.2 +/- 2.5; P < .01). IMPLICATIONS: Among pediatric residents, formal teaching enhances knowledge acquisition relative to self-study and lecture attendance.

Adult↗

PubMed1996

Computer instruction in learning concepts of streptococcal pharyngitis.

OBJECTIVE: To evaluate a computer-assisted instruction unit covering the basic concepts of streptococcal pharyngitis for effectiveness as a learning tool. DESIGN: Randomized control trial. SETTING: A medical school associated with a tertiary care hospital. PARTICIPANTS: Third-year medical students on a pediatric clerkship from December 1, 1992, to October 31, 1993. INTERVENTION: Students were randomized into a study or a control group and given a pretest on streptococcal pharyngitis. The study group then completed the computer-assisted instruction unit. No attempt was made to distinguish among the clinical experiences of the two groups during the next 4 weeks, after which a second test on streptococcal pharyngitis was given to both groups. MAIN OUTCOME MEASURES: Outcome was measured by scores (percentage correct) from tests given at day 1 and week 4 of the clerkship. RESULTS: The posttest scores of the study group increased by an average of 12.1 above the pretest scores, but the scores of the control group were only 3.4 points higher. The difference between these increases is statistically significant (P < .01, Student's t test). CONCLUSION: Short, well-designed computer-assisted instruction units can be effective tools in medical education.

Adult↗

PubMed2004

Is this patient dead, vegetative, or severely neurologically impaired? Assessing outcome for comatose survivors of cardiac arrest.

CONTEXT: Most survivors of cardiac arrest are comatose after resuscitation, and meaningful neurological recovery occurs in a small proportion of cases. Treatment can be lengthy, expensive, and often difficult for families and caregivers. Physical examination is potentially useful in this clinical scenario, and the information obtained may help physicians and families make accurate decisions about treatment and/or withdrawal of care. OBJECTIVE: To determine the precision and accuracy of the clinical examination in predicting poor outcome in post-cardiac arrest coma. DATA SOURCES AND STUDY SELECTION: We searched MEDLINE for English-language articles (1966-2003) using the terms coma, cardiac arrest, prognosis, physical examination, sensitivity and specificity, and observer variation. Other sources came from bibliographies of retrieved articles and physical examination textbooks. Studies were included if they assessed the precision and accuracy of the clinical examination in prognosis of post-cardiac arrest coma in adults. Eleven studies, involving 1914 patients, met our inclusion criteria. DATA EXTRACTION: Two authors independently reviewed each study to determine eligibility, abstract data, and classify methodological quality using predetermined criteria. Disagreement was resolved by consensus. DATA SYNTHESIS: Summary likelihood ratios (LRs) were calculated from random effects models. Five clinical signs were found to strongly predict death or poor neurological outcome: absent corneal reflexes at 24 hours (LR, 12.9; 95% confidence interval [CI], 2.0-68.7), absent pupillary response at 24 hours (LR, 10.2; 95% CI, 1.8-48.6), absent withdrawal response to pain at 24 hours (LR, 4.7; 95% CI, 2.2-9.8), no motor response at 24 hours (LR, 4.9; 95% CI, 1.6-13.0), and no motor response at 72 hours (LR, 9.2; 95% CI, 2.1-49.4). The proportion of individuals' dying or having a poor neurological outcome was calculated by pooling the outcome data from the 11 studies (n = 1914) and used as an estimate of the pretest probability of poor outcome. The random effects estimate of poor outcome was 77% (95% CI, 72%-80%). The highest LR increases the pretest probability of 77% to a posttest probability of 97% (95% CI, 87%-100%). No clinical findings were found to have LRs that strongly predicted good neurological outcome. CONCLUSIONS: Simple physical examination maneuvers strongly predict death or poor outcome in comatose survivors of cardiac arrest. The most useful signs occur at 24 hours after cardiac arrest, and earlier prognosis should not be made by clinical examination alone. These data provide prognostic information, rather than treatment recommendations, which must be made on an individual basis incorporating many other variables.

Brain Death↗

PubMed2005

Comparison of the instructional efficacy of Internet-based CME with live interactive CME workshops: a randomized controlled trial.

CONTEXT: Despite evidence that a variety of continuing medical education (CME) techniques can foster physician behavioral change, there have been no randomized trials comparing performance outcomes for physicians participating in Internet-based CME with physicians participating in a live CME intervention using approaches documented to be effective. OBJECTIVE: To determine if Internet-based CME can produce changes comparable to those produced via live, small-group, interactive CME with respect to physician knowledge and behaviors that have an impact on patient care. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial conducted from August 2001 to July 2002. Participants were 97 primary care physicians drawn from 21 practice sites in Houston, Tex, including 7 community health centers and 14 private group practices. A control group of 18 physicians from these same sites received no intervention. INTERVENTIONS: Physicians were randomly assigned to an Internet-based CME intervention that could be completed in multiple sessions over 2 weeks, or to a single live, small-group, interactive CME workshop. Both incorporated similar multifaceted instructional approaches demonstrated to be effective in live settings. Content was based on the National Institutes of Health National Cholesterol Education Program--Adult Treatment Panel III guidelines. MAIN OUTCOME MEASURES: Knowledge was assessed immediately before the intervention, immediately after the intervention, and 12 weeks later. The percentage of high-risk patients who had appropriate lipid panel screening and pharmacotherapeutic treatment according to guidelines was documented with chart audits conducted over a 5-month period before intervention and a 5-month period after intervention. RESULTS: Both interventions produced similar and significant immediate and 12-week knowledge gains, representing large increases in percentage of items correct (pretest to posttest: 31.0% [95% confidence interval {CI}, 27.0%-35.0%]; pretest to 12 weeks: 36.4% [95% CI, 32.2%-40.6%]; P<.001 for all comparisons). Chart audits revealed high baseline screening rates in all study groups (> or =93%) with no significant postintervention change. However, the Internet-based intervention was associated with a significant increase in the percentage of high-risk patients treated with pharmacotherapeutics according to guidelines (preintervention, 85.3%; postintervention, 90.3%; P = .04). CONCLUSIONS: Appropriately designed, evidence-based online CME can produce objectively measured changes in behavior as well as sustained gains in knowledge that are comparable or superior to those realized from effective live activities.

Education, Medical, Continuing↗

PubMed1975

Effect of induced locus of control on change in field independence.

Three groups, alike in Rod and Frame Test (RFT) scores on pretesting, were given different instructions for Rotter's Locus of Control scale. Thirty-two Ss were told to fake internal or external answers. Another 16 Ss were instructed to answer the scale according to their own actual beliefs. Analysis of RFT pretest-posttest changes revealed that in both experimental conditions initially field-dependent Ss changed in the direction of higher field independence, and field-independent Ss shifted toward higher field dependence. The total amount of change manifested by field-dependent Ss in both conditions was in excess of the change by field-independent Ss. Standard test-taking instructions raised the level of field independence for field-dependent and field-independent Ss, with the magnitude of change greater among field-independent Ss. When Ss given internal and external instructions filled out the Locus of Control scale again at the end of the experiment, field-independent Ss professed to hold significantly more beliefs than field-dependent Ss that were coincident with beliefs of their previously simulated role. The findings were discussed primarily in terms of the relationship between role-playing and development of identity.

Female↗

PubMed1976

The effect of structured and unstructured leader roles on internal and external group participants.

This study assessed the impact of structured and unstructured leader roles on measures of outcome for Ss who differed on the pretest dimension "locus of control." On the basis of their pretest locus of control scores, Ss were assigned to a structured or an unstructured marathon group. The treatment in the two 16-hour -arathons consisted of a defined series of exercises; the only difference between the two groups was the degree of leader control over member participation. As predicted, internal Ss in the unstructured group rated the leader and the group more psoitively than did external Ss, while the reverse responsivity occured in the structured group. Significant Locus of Control X Treatment interactions indicated that internal and external Ss reflected differential shifts in general anxiety, general depression, and locus of control as a function of treatment. The relationship between changes in self-actualization and locus of control and changes in conflict-handling styles and negative affects differed as a function of locus of control and treatment condition. The overall results coupled with prior findings tentatively support the appropriateness of an unstructured leader role for internal scores and a structured leader role for external scorers.

Adolescent↗

PubMed1983

Stability, concurrent and predictive validity of the PPVT-R.

Explored the relationship between the Peabody Picture Vocabulary Test-Revised (PPVT-R) and the Peabody Individual Achievement Test (PIAT), and pretest PPVT-R standard scores administered about 7 months earlier for a sample of 29 mentally retarded children between the ages of 5-5 and 12-7 (mean = 9-6, SD = 1-11). Pretest PPVT-R scores correlated moderately with PIAT standard scores (Median r = .43) and with posttest PPVT-R scores (r = .81). There was no significant difference between the mean pre and post PPVT-R scores (60.3 and 58.5, respectively). The PPVT-R and PIAT Total Test Score administered in the same session correlated .71 (Median r with the PIAT's subtests = .64). Implications are discussed in light of the stability and predictive and concurrent validity of the PPVT-R for this sample.

Aptitude Tests↗

PubMed1984

Dramatic induction of depressive mood.

Conducted an experiment (N = 105) wherein one group was exposed to a sad film in order to induce depressive feelings and another group was shown an emotionally neutral film. Two VROPSOM depressive affect checklists (the Dutch version of the DACL) were administered in a pretest-posttest design. Respondents who had watched the grievous movie reported more depressive mood, as compared to both the respondents at pretesting and those who had watched the neutral film. Specific analyses confirmed that it was a depressive emotional state that had been induced. These experimental effects, as well as intercorrelations with enduring depression, adjustment and approval-seeking, attested to the construct validity of the VROPSOM lists.

Adult↗

PubMed1988

Effects of education and relaxation training with essential hypertension patients.

Thirty subjects with essential hypertension were assigned randomly to either a no treatment control, education, or education with relaxation training group. Independent blood pressure recordings were collected by medical staff at pretest, posttest, and 8-week follow-up. Results suggest a significant interaction between treatment and time for the dependent physiological measure, systolic blood pressure. During the pretest to follow-up period, the control group averaged a 5.9 mm. Hg. increase, the education with relaxation group an 8.8 mm. Hg. decrease, and the education group a 14.9 mm. Hg. decrease in systolic blood pressure. There was no significant difference in group means for diastolic blood pressure within groups over time. As measured at follow-up, education appeared more effective in reducing systolic blood pressure than education with relaxation training. More than one-third of subjects associated unpleasant side effects with their antihypertensive medication. Almost all treatment subjects rated the education and relaxation as helpful for understanding and managing their hypertension.

Adult↗

PubMed1987

Attitudes of persons at risk for Huntington disease toward predictive testing.

Attitudes of 69 persons at risk for Huntington disease (HD) were obtained by means of semistructured interviews and questionnaires. About 79% of the individuals said that they would use a presymptomatic predictive test if it were available. All believed that the test should be made available even though there was no cure for HD. Nearly 2/3 of subjects would use the test for prenatal diagnosis, and of these 71% would terminate a pregnancy if the fetus was found to carry the HD gene. Most subjects believed that pretest counseling should be mandatory and many said that testing should be withheld from persons who were psychologically unstable or were threatening self-harm. The data suggest that about 2-6% of persons at risk for HD may have severe psychiatric or suicidal responses to a positive outcome of predictive testing. This underscores the need for adequate pretest counseling and the availability of professional and community resources to deal with the impact of predictive testing on individuals and their relatives.

Adult↗

PubMed1993

AI/LEARN/Rheumatology. A comparative study of computer-assisted instruction for rheumatology.

OBJECTIVE: To assess the effectiveness of AI/LEARN/Rheumatology, a computer-controlled interactive videodisc system for teaching. METHODS: We assessed improvement in knowledge about rheumatic diseases, using a pretest and posttest in a control year and a treatment year. The subjects were medical students and postgraduate trainees taking the rheumatology elective. The control year used traditional lectures and the standard rheumatology curriculum. The treatment year used AI/LEARN/Rheumatology in place of lectures on rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis. RESULTS: The trainees showed significant improvement in knowledge in both the control year and the treatment year (P < 0.0001 for both). The average time spent using AI/LEARN/Rheumatology was similar to the time spent in lectures (3 hours). The number of patient consultations in which trainees participated was lower in the treatment year than in the control year; however, the adjusted posttest scores using the pretest as a covariate tended to be higher in the treatment year (P = 0.10). Analysis of covariance of the adjusted posttest scores for the treatment year only showed that the trainees who spent more time using AI/LEARN/Rheumatology learned more (r = 0.57). Trainees felt that AI/LEARN/Rheumatology was the most helpful educational experience of the elective. CONCLUSION: AI/LEARN/Rheumatology is an effective means of teaching about the rheumatic diseases. It has many advantages: availability for independent study, effective use of trainee's time, and liberation of faculty time from lectures. Trainees enjoyed using AI/LEARN/Rheumatology.

Computer-Assisted Instruction↗

PubMed2004

Spanish Arthritis Empowerment Program: a dissemination and effectiveness study.

OBJECTIVE: To evaluate the effectiveness of the Spanish Arthritis Empowerment Program as presented by the Arthritis Foundation, Southern California Chapter, in Orange County, California. METHODS: Participants with arthritis (n = 141) enrolled in the program between October 1999 and May 2001. All materials were in Spanish. Written pretest, 6-week posttest, and 6-month followup tests measured pain rating, self-report joint counts, function (modified Health Assessment Questionnaire [mHAQ]), self efficacy, self-care behavior, and arthritis knowledge. RESULTS: Mean age was 51 years, 92% were female, 84% were born in Mexico, 55% had sixth grade education or less, and 60% had no medical insurance. Of the 141 participants, 118 completed 6-month followup testing. Repeated-measures analysis of variance showed significant improvement from pretest to 6-month followup in pain (6.0 versus 3.4); self efficacy (5.5 versus 8.4), self-care behavior (1.7 versus 4.9), arthritis knowledge (1.6 versus 4.5), and general health (2.1 versus 2.5), all at P < 0.001. Small improvement was reported in mHAQ (0.56 versus 0.50; P = 0.024). CONCLUSION: The Spanish Arthritis Empowerment Program was successfully disseminated. Significant improvements in self efficacy and in arthritis symptoms were maintained at the 6-month followup.

Analysis of Variance↗

PubMed2007

Latin and Greek in gross anatomy.

BACKGROUND: Medical students and practitioners learn and use a vocabulary originating almost entirely from classical Latin and Greek languages. Previous generations required Latin or Greek prior to medical school, but the current generation does not have such requirements. Anecdotal evidence suggests that understanding Latin or Greek helps students to learn and practitioners to recall otherwise foreign terminology. This study evaluated students' familiarity with Latin and Greek etymologies before and after a gross anatomy course that incorporated etymologies into its curriculum. METHODS: First-year medical students at Mayo Clinic College of Medicine were taught Latin and Greek etymologies through lectures and handouts during their gross anatomy course. They took a pretest and a posttest before and after the course to assess their understanding of etymologies. In addition, students from all four years of medical school, residents, and staff physicians also took a general etymology quiz to assess their understanding of etymologies. RESULTS: After their gross anatomy course emphasizing etymologies, first-year students scored higher on the posttest than they did on the pretest. First-year students also reported that learning etymologies enhanced anatomy learning, made the experience more enjoyable, and proved to be less difficult than they thought it would be prior to the course. Medical students, residents, and staff physicians scored almost equally on the general etymology quiz and almost equally reported that etymologies enhanced learning and recalling terminology. Medical students, residents, and staff physicians almost equally endorsed incorporating etymologies into medical education. CONCLUSIONS: This study provides novel scientific evidence that a basic understanding of Latin and Greek etymologies enhances performance and comfort when learning and using medical terminology.

Anatomy↗

PubMed2006

Effects of a distance learning program on physicians' opioid- and benzodiazepine-prescribing skills.

INTRODUCTION: Opioid misuse is common among patients with chronic nonmalignant pain. There is a pressing need for physicians to increase their confidence and competence in managing these patients. METHODS: A randomized controlled trial of family physicians (N = 88) attending 1 of 4 continuing medical education events helped to determine the effectiveness of e-mail case discussions in changing physician behavior. Before random assignment, participants completed a pretest and attended a 3-hour didactic session on prescribing opioids and benzodiazepines. The intervention group participated in 10 weeks of e-mail case discussions, with designated participants responding to questions on cases. An addictions physician facilitated the discussion. Several months after the e-mail discussion, participants took part in a mock telephone consultation; a blinded researcher posing as a medical colleague asked for advice about 2 cases involving opioid and benzodiazepine prescribing. Using a checklist, the researcher recorded the questions asked and advice given by the physician. RESULTS: On post-testing, both groups expressed greater optimism about treatment outcomes and were more likely to report using a treatment contract and providing advice about sleep hygiene. There were no significant differences between pretesting and post-testing between the groups on the survey. During the telephone consultation, the intervention group asked significantly more questions and offered more advice than the control group (odds ratio for question items, 1.27 [p = .03]; advice items, 1.33 [p = .01). DISCUSSION: Facilitated by electronic mail and a medical expert, case discussion is an effective means of improving physician performance. Telephone consultation holds promise as a method for evaluating physicians' assessment and management skills.

Adult↗

PubMed2001

Accelerated dobutamine stress testing: safety and feasibility in patients with known or suspected coronary artery disease.

BACKGROUND: Dobutamine pharmodynamics require approximately 10 min to reach steady state. Despite this, standard dobutamine stress echo typically uses 3-min stages of advancing dobutamine doses because of safety concerns. HYPOTHESIS: In patients with a high pretest probability of coronary artery disease (CAD), a continuous infusion of high-dose dobutamine is a feasible and safe method for performing a dobutamine stress test. METHODS: Forty-seven consecutive patients (mean age 64 +/- 11 years) with 3.0 +/- 1.4 cardiac risk factors underwent dobutamine stress testing utilizing a single, high-dose (40 mcg/kg/min), continuous dobutamine infusion. The 40 mcg/kg/min infusion was continued for up to 10 min or until a test endpoint had been reached. If a test endpoint was not achieved, atropine (up to 1.0 mg) was added. RESULTS: Heart rate rose from 71 +/- 12 to 137 +/- 18 beats/min at peak (p<0.0001) with a concomitant change in systolic blood pressure (143 +/- 35 vs. 167 +/- 38 mmHg; p = 0.001) but no change in diastolic blood pressure (74 +/- 19 vs. 75 +/- 18 mmHg; p = NS). Target heart rate was achieved in 20 of 47 (43%) patients with accelerated dobutamine alone and in 34 of 47 (72%) with the addition of atropine. An average of 11.6 +/- 3.7 min was required to obtain target heart rate. Subjective sensations from the dobutamine occurred in 49% of patients (palpitations 21%, nausea 6%, chest pain 6%, headache 6%, dizziness 13%), mild arrhythmia in 48% of patients (ventricular premature beats 38%, supraventricular tachycardia 10%), and one patient had nonsustained ventricular tachycardia. CONCLUSION: A single, high-dose (40 mcg/kg/min) dobutamine-atropine protocol provides an efficient means of performing dobutamine stress echocardiography with a similar symptom profile as conventional dobutamine infusion protocols in patients with a high pretest probability of CAD. Randomized, controlled studies will be necessary to assess the sensitivity and specificity of this accelerated dobutamine echo protocol.

Aged↗

PubMed2001

Secondary prevention of depressive symptoms in elderly inhabitants of residential homes.

The effects of a multifaceted secondary prevention intervention in residential homes in the Netherlands were examined, using a quasi-experimental design. In five experimental residential homes, the caregivers received three training sessions on detecting depression and on supporting depressed residents. Furthermore, an information session was organized for all personnel, a further session was organized for residents and their relatives, and several group interventions were offered. 213 residents participated in the study. 211 residents of five other residential homes, matched on basic variables, served as a comparison group. Effects on depressive symptoms (geriatric depression scale) and health related quality of life (MOS-SF-36) were measured at pretest and after the intervention, one year later. Because the drop-out rate was high and drop-outs differed significantly from the remaining population, the scores of drop-outs were imputed. Since we used a quasi-experimental design, we controlled for confounding variables. Regression analyses resulted in significant effects of the intervention on the GDS and on role functioning in the total population. When the analyses were limited to those scoring high on the GDS at pretest, significant effects were found on the GDS, and on four domains of health-related quality of life: psychological distress, role functioning, pain and social functioning. The improvement in GDS scores in GDS cases was significantly larger than in other subjects. Our results suggest that general approaches aimed at a residential home are capable of influencing depressive symptoms in inhabitants. Possibly, it may not be necessary to wait until depressive symptoms have escalated and inhabitants need extensive treatment.

Aged↗

PubMed1977

Morphological transformation of early passage golden Syrian hamster embryo cells derived from cryopreserved primary cultures as a reliable in vitro bioassay for identifying diverse carcinogens.

Cryopreserved primary cultures of golden Syrian hamster embryo cells were used as the source of target and feeder cells for establishing an in vitro carcinogenesis bioassay. The primary culture giving the best overall response in a pretest before freezing gave positive results in 20 consecutive experiments when retested with 3-methylcholanthrene after cryopreservation, indicating that pretested cryopreserved cultures can serve as a source of susceptible target cells in an in vitro carcinogenesis bioassay. Similarly prepared and cryopreserved cultures served satisfactorily as feeder cells. Susceptible positive cultures were used to test a large number of carcinogenic and non-carcinogenic chemicals in this system. The results showed a very high positive correlation (90.8%) between morphological transformation and the reported carcinogenic activity of the chemicals. Transformation was not observed when cells were tested with a few carcinogens that may not be metabolized to their active forms by early passage hamster embryo cells. N-2-acetylaminofluorene transformed cells only when tested in the presence of hamster liver microsomes. No false positive results were obtained when non-carcinogens were bioassayed, nor was spontaneous transformation observed in control cultures treated with medium alone, 0.2% dimethylsulfoxide or other solvents. Cultures derived from morphologically transformed colonies arising after treatment of cells with several known carcinogens were tumorigenic in vivo, confirming the correlation of morphological transformation with tumorigenicity and the validity of altered morphology as an in vitro criterion for carcinogenicity in vivo.

Animals↗