Biomedical subjects

M J Egger

Publications and source records attributed to M J Egger.

At least 19 recordsLinked to original sources

PubMed2000

Lens opacifications detected by slitlamp biomicroscopy are associated with exposure to organic nitrate explosives.

CONTEXT: Unusual cataracts (flecks) have been reported to occur at very low levels of trinitrotoluene exposure, but prevalence estimates vary widely. Cataracts have not been reported among workers in the United States exposed to organic nitrate explosives. OBJECTIVES: To determine the prevalence of unusual cataracts in a population of workers in the United States exposed to organic nitrate explosives, to determine whether associations exist with reported cataract risk factors, and to determine if other eye effects (eg, retinal hemorrhage) are associated with exposure. DESIGN: Cohort prevalence study. SETTING: A university-based ophthalmologic clinic. SUBJECTS: Sixty-one workers from an explosives plant comprised the exposed group. The comparison group consisted of 56 workers using chemicals other than organic nitrate explosives. OUTCOME MEASURES: The primary outcome measure was opacifications (flecks) of the crystalline lens, graded clinically on a scale of 0 to 4 +. Additional measures included visual acuity, applanation tonometry, and clinical evaluation using standard examination techniques. RESULTS: Sixty-three percent of the workers had anterior cortical lens opacifications in a pattern of peripheral flecks. Exposed subjects were 18 times more likely to exhibit changes than those not exposed, a statistically significant association (95% confidence interval [CI], 5.0-65.0; P<.001). A statistically significant association with the duration of exposure was also found. CONCLUSIONS: Asymptomatic, low-grade cataracts (flecks) were identified in 63% of the workers exposed to pentolite. No other eye effects were found to be associated with exposure. Cataracts were not associated with other known risk factors, but were associated with the duration of exposure. Biomicroscopy is widely available and useful for detecting changes in the asymptomatic stages.

Adult↗

PubMed1999

The laparoscopic management of appendicitis and cholelithiasis during pregnancy.

BACKGROUND: Laparoscopic management of appendicitis and symptomatic cholelithiasis during pregnancy remains controversial. We report the single largest series of laparoscopic cholecystectomies and appendectomies during pregnancy. METHODS: Medical records of all pregnant patients who underwent open or laparoscopic management of appendicitis/cholelithiasis at LDS Hospital from 1990 to 1998 were reviewed. RESULTS: Eighteen open appendectomies (OA) and 13 open cholecystectomies (OC) were performed. Forty-five laparoscopic cholecystectomies (LC) and 22 laparoscopic appendectomies (LA) were performed without birth defects, fetal loss or uterine injury. Preterm delivery rates (PTD) in the LA and OA groups were similar (15.8% versus 11.8%, P>0.9). The PTD rate in the LC group was not significantly different than in the OC group (11.9% versus 10.0%, P>0.9). Neither birth weights nor Apgar scores were significantly different across groups. CONCLUSIONS: Laparoscopic management of appendicitis and symptomatic cholelithiasis during pregnancy can be performed with minimal fetal and maternal morbidity when accepted management guidelines are followed.

Adult↗

PubMed1999

Variability in physician opinion on limiting pediatric life support.

OBJECTIVE: We conducted this study to investigate how physicians in a pediatric intensive care unit (ICU) currently make decisions to withdraw and withhold life support. Consultation with the patient's primary caregiver often precedes decisions about withdrawal and limitation of life support in chronically ill patients. In these scenarios, the patient's primary caregiver was the pediatric oncologist. To evaluate the influence of subspecialty training, we compared the attitudes of the pediatric intensivists and the oncologists using scenarios describing critically ill oncology patients. DESIGN: Cross-sectional survey. Each physician was randomly assigned 4 of 8 potential case scenarios. SETTING: A total of 29 American pediatric ICUs. PARTICIPANTS: Pediatric intensive care and oncology attendings and fellows. INTERVENTION: Systematic manipulation of patient characteristics in two hypothetical case scenarios describing 6-year-old female oncology patients presenting to the ICU after the institution of mechanical ventilator support for acute respiratory failure. Cases 1 through 4 described a patient who, before admission, had a 99% projected 1-year probability of survival from her underlying cancer and suffered from severe neurologic disabilities. Cases 5 through 8 described a patient who was neurologically normal before admission and had a <1% chance of surviving longer than 1 year because of her underlying cancer. Each physician was randomly assigned 2 cases from cases 1 through 4 and 2 cases from cases 5 through 8. Within each of these case scenarios, parental preferences (withdraw or advance support or look for guidance from the caregivers) and probability of survival (5% vs 40%) were manipulated. Before distribution, the survey instrument was pilot-tested and underwent a rigorous assessment for clinical sensibility. PRIMARY OUTCOME MEASURES: Physicians ratings of the importance of 10 factors considered in the decision to withdraw life support, and their decisions about the appropriate level of care to provide. Respondents were offered five management options representing five levels of care: 1) discontinue inotropes and mechanical ventilation but continue comfort measures; 2) discontinue inotropes and other maintenance therapy but continue mechanical ventilation and comfort measures; 3) continue with current management but add no new therapeutic intervention; 4) continue with current management, add additional inotropes, change antibiotics and the like as needed, but do not start dialysis; and 5) continue with full aggressive management and plan for dialysis if necessary. Respondents also were asked whether they would obtain an ethics consultation. RESULTS: A total of 270 physicians responded to our survey (165 of 198 potentially eligible pediatric intensivists and 105 of 178 pediatric oncologists for response rates of 83% and 59%, respectively). The respondents considered the probability of ICU survival and the wishes of the parents regarding the aggressiveness of care most important in the decision to limit life-support interventions. No clinically important differences were found when the responses of oncologists were compared with those of intensivists. In six of eight possible scenarios, the same level of intensity of care was chosen by less than half of all respondents. In three scenarios, >/=10% of respondents chose full aggressive management as the most appropriate level of care, whereas another >/=10% chose comfort measures only when viewing the same scenario. The most significant respondent factors affecting choices were professional status (attending vs fellow) and the self-rated importance of functional neurologic status. The majority of respondents (83%) believed that the intensive care and the oncology staff were usually in agreement at their institution about the level of intervention to recommend to the parents. (ABSTRACT TRUNCATED)

Child↗

PubMed1999

Early undifferentiated connective tissue disease (CTD). VI. An inception cohort after 10 years: disease remissions and changes in diagnoses in well established and undifferentiated CTD.

OBJECTIVE: (1) To review the diagnoses after 10 years in patients who were identified within 12 months of the onset of well established and undifferentiated connective tissue diseases (CTD). (2) To examine the death rates and disease remissions in these patients. METHODS: This inception cohort of 410 patients had less than one year of signs and/or symptoms of CTD. Diagnoses of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and poly/dermatomyositis (PM/DM) were made in 197 patients using accepted diagnostic and classification criteria. Diagnoses of undifferentiated CTD were made in 213 patients. These latter patients were placed in 3 categories: isolated Raynaud's phenomenon (RP), unexplained polyarthritis (UPA), and undifferentiated CTD (UCTD), defined as meeting at least 3 of 11 specific manifestations of CTD. The diagnoses and remissions in all patients after 10 years were determined. RESULTS: Patients with well established CTD tended to remain with the original diagnosis. The 10 year survival was at least 87% in all diagnostic categories, with the exception of SSc, in which it was 56%. The progression of UPA to RA occurred infrequently. The presence of antinuclear antibodies suggested that UPA may develop additional symptoms and/or a specific diagnosis, and RP in these patients increased the likelihood of progressing to UCTD or a specific well established CTD. Ten percent of patients with RP progressed to SSc. In patients with UCTD, joint pain/tenderness and swelling counts were associated with progression to other diagnoses including RA, while either serositis, malar rash, or discoid lupus suggested the eventual diagnosis of SLE. CONCLUSION: The survival of patients with SSc was poor, with most dying early in the course of their disease. Remissions were seen in all groups of patients except SSc. The remissions were sometimes transient in SLE. Undifferentiated disease at initial examination within 12 months of onset usually remains undifferentiated.

Connective Tissue Diseases↗

PubMed1998

Early undifferentiated connective tissue disease. V. An inception cohort 5 years later: disease remissions and changes in diagnoses in well established and undifferentiated connective tissue diseases.

OBJECTIVE: To review the diagnoses after 5 years in patients who were identified within 12 months of the onset of well established and undifferentiated connective tissue diseases (CTD); to examine death rates and disease remissions in these patients. METHODS: This inception cohort of 410 patients was identified in 10 academic rheumatology practices. They had less than one year of signs and/or symptoms of CTD. Diagnoses of specific well established CTD were made using accepted diagnostic and classification criteria. The diagnoses after 5 years were determined. RESULTS: Patients with well established CTD tended to remain with the original diagnosis. The progression of unexplained polyarthritis to rheumatoid arthritis occurred infrequently. Ten percent of patients with isolated Raynaud's phenomenon progressed to systemic sclerosis (SSc). The 5 year survival was over 90% in all diagnostic categories, with the exception of SSc, in which it was 64%. CONCLUSION: Patients with a well established CTD usually continued with the same diagnosis. Patients with undifferentiated CTD tended to remain undifferentiated or to remit.

Arthritis↗

PubMed1997

Lymphoblast morphology in predicting leukemic meningeal relapse with low chamber count and lymphoblasts.

The diagnostic criteria for meningeal relapse (MR) of acute lymphoblastic leukemia (ALL) are a cerebrospinal fluid (CSF) chamber count of more than five leukocytes per microliter and a cytomorphological evaluation revealing lymphoblasts. A dilemma arises when confronted with a patient with a low CSF white blood cell (WBC) chamber count and lymphoblasts. We utilized a scoring system to review lymphoblast morphology in 12 such patients. A cell was defined as a lymphoblast if it could not be easily categorized as a lymphocyte, monocyte. histiocyte, or granulocyte. Each lymphoblast was scored on four parameters: presence of nucleoli, homogeneous distribution of chromatin, nucleocytoplasmic ratio greater than 75%, and nuclear irregularity. Cells were scored without knowledge of the patients' out come. Seven patients eventually developed MR by current criteria and five patients never relapsed. The mean lymphoblast scores for patients that did and did not relapse were 2.35 and 1.53, respectively (P < .001). The percent of cells scored as lymphoblasts was also significantly higher in patients that relapsed, 36.9% vs. 19.4% (P = .01). Our study shows that careful cytomorphologic analysis can predict which patients with low chamber counts and "blasts" on cytocentrifuge examination will progress to meningeal relapse. We recommend reviewing the definition of MR and using a scoring system when confronted with blasts in a low chamber count cerebrospinal fluid specimen.

Adolescent↗

PubMed1997

Electron arc irradiation of the postmastectomy chest wall: clinical results.

BACKGROUND AND PURPOSE: Since 1980 electron arc irradiation of the postmastectomy chest wall has been the preferred technique for patients with advanced breast cancer at our institution. Here we report the results of this technique in 140 consecutive patients treated from 1980 to 1993. MATERIALS AND METHODS: Thoracic computerized tomography was used to determine internal mammary lymph node depth and chest wall thickness, and for computerized dosimetry calculations. Total doses of 45-50 Gy in 5 to 5 1/2 weeks were delivered to the chest wall and internal mammary lymph nodes via electron arc and, in most cases, supraclavicular and axillary nodes were treated with a matching photon field. Patients were assessed for acute and late radiation changes, local and distant control of disease, and survival. Patients had a minimum follow-up of 1 year after completion of radiation treatment, and a mean follow up interval of 49 months and a median of 33 months. All patients had advanced disease: T stages 1, 2, 3, and 4 represented 21%, 39%, 21% and 19% of the study population, with a mean number of positive axillary lymph nodes of 6.5 (range, 0-29). Analysis was performed according to adjuvant status (no residual disease, n = 90), residual disease (positive margin, n = 15, and primary radiation, n = 2), or recurrent disease (n = 33). RESULTS: Acute radiation reactions were generally mild and self limiting. A total of 26% of patients developed moist desquamation, and 32% had brisk erythema. Actuarial 5 year local-regional control, freedom from distant failure, and cause-specific survival was 91%, 64%, and 75% in the adjuvant group; 84%, 50%, and 53% in the residual disease group; and 63%, 34%, and 32% in the recurrent disease group, respectively. In univariate Cox regressions, the number of positive lymph nodes was predictive for local failure in the adjuvant group (P = 0.037). Chronic complications were minimal with 11% of patients having arm edema, 17% hyperpigmentation, and 13% telangectasia formation. CONCLUSION: These data demonstrate that local-regional control with electron are therapy of the postmastectomy chest wall is comparable to photon techniques. Acute radiation reactions are well tolerated and mostly of minor extent. A previous report demonstrated a significant reduction in the dose-volume relationship of the lung using the electron arc compared with two photon techniques. Consequently, with careful attention to treatment planning and dosimetry, electron arc therapy of the postmastectomy chest wall is safe and effective. The radiation dose to heart and lung is minimized without compromise on local control.

Adult↗

PubMed1997

Transrectal ultrasound versus digital rectal examination for the staging of carcinoma of the prostate: results of a prospective, multi-institutional trial.

PURPOSE: We determined the accuracy of transrectal ultrasonography versus digital rectal examination in staging the local extent of biopsy proved carcinoma of the prostate. MATERIALS AND METHODS: A National Institutes of Health funded network was developed to perform prospective, multi-institutional trials. A total of 386 patients judged by the investigators to be candidates for radical prostatectomy underwent transrectal ultrasonography with recording of data according to a numerical analog for construction of receiver operating characteristic curves. The results of digital rectal examination were similarly recorded. After radical prostatectomy whole mount histology was performed on all surgical specimens, and pathological findings were correlated with preoperative transrectal ultrasound and digital rectal examination results. RESULTS: The calculated area under the curve for transrectal ultrasound in predicting extracapsular tumor extension was 0.69 compared to 0.72 for digital rectal examination (p = 0.64), while that for predicting seminal vesicle invasion was 0.74 and 0.69, respectively (p = 0.36). There was a nonstatistically significant trend for improved accuracy of both examinations as tumor volume increased. Transrectal ultrasound was more accurate for staging posterior cancers than for those in the anterior portion of the prostate. CONCLUSIONS: Neither transrectal ultrasound nor digital rectal examination proved to be superior to each other for staging the local extent of prostate cancer. No imaging modality or examination that depends on gross architectural changes is likely to have a high degree of accuracy in detecting microscopic extension of extracapsular tumor frequently observed in radical prostatectomy specimens.

Adenocarcinoma↗

PubMed1997

Transrectal prostate ultrasonography: variability of interpretation.

PURPOSE: The current study was designed to compare the interpretation of the individual performing transrectal ultrasound examination (operator) with experienced individuals who interpreted the examination with and without the availability of clinical data. Inter-observer and intra-observer variability was compared to determine the reproducibility and reliability of the study. MATERIALS AND METHODS: All patients undergoing radical prostatectomy for treatment of localized carcinoma of the prostate underwent a transrectal ultrasound examination before the procedure. The sonogram was interpreted by the operator and reviewers. The radical prostatectomy specimen was examined pathologically and the staging as determined by ultrasound was compared with the pathological findings. RESULTS: Ultrasound operator accuracy for extracapsular extension and seminal vesicle invasion was 0.70 and 0.74, respectively, compared with the accuracy of the reviewers, which ranged from 0.59 to 0.75 and 0.44 to 0.74 for extracapsular extension and seminal vesicle invasion, respectively. In general, blinded reviews were less accurate than unblinded reviews but this was only statistically significant for 2 reviewers. CONCLUSIONS: Although for most reviewers the addition of clinical data did not improve the accuracy of the interpretation, an advantage was noted for the operator, that is, the individual performing the examination. In general, the technical quality of the examination was related to the accuracy of the readings.

Humans↗

PubMed1995

Reliability and validity of the CSSRD functional assessment survey in rheumatoid arthritis. Cooperative Systematic Studies of Rheumatic Diseases.

OBJECTIVE: To demonstrate the reliability and validity characteristics of a fast, intensively focused functional assessment questionnaire that has been used in rheumatoid arthritis clinical trials by the Cooperative Systematic Studies of Rheumatic Diseases group (CSSRD). METHODS: Data from three double-blind, controlled clinical trials by CSSRD were used to examine the properties of the Functional Assessment Survey as a measure of physiologic function. RESULTS: The Functional Assessment Survey has reasonable test-retest reliability and convergent validity with the Steinbrocker et al. functional class. It demonstrated appropriate divergent validity with other clinical measures of response, as well as discriminant validity. CONCLUSIONS: The CSSRD Functional Assessment Survey is brief, intensive, and focused. Reliability and validity characteristics have been documented.

Activities of Daily Living↗

PubMed1995

High-resolution computed tomography sampling for detection of asbestos-related lung disease.

RATIONALE AND OBJECTIVES: We determined whether a limited number of high-resolution computed tomography (HRCT) scans will effectively screen for interstitial lung disease (ILD) in a population of individuals exposed to asbestos. METHODS: We retrospectively reviewed the computed tomography studies of 49 patients exposed to asbestos. HRCT in the supine and prone positions had been performed at specifically preselected levels. Two teams of thoracic radiologists evaluated, on separate occasions: (1) all images, (2) prone images only, and (3) a single prone image through the lung bases for the presence of diffuse ILD. RESULTS: A relatively high level of accuracy was obtained with a single prone scan. However, improvement to 95% or better was found when additional prone images were used. CONCLUSION: A screening study for ILD, in this case patients exposed to asbestos, may be performed by preselected prone HRCT images only. The ease and decreased time of performing the procedure make screening relatively large patient groups for ILD more feasible.

Asbestos↗

PubMed1994

Comparison of hydroxychloroquine and placebo in the treatment of the arthropathy of mild systemic lupus erythematosus.

OBJECTIVE: To compare the relative safety and efficacy of hydroxychloroquine (HCQ) and placebo (Pl) in the treatment of the articular complaints of systemic lupus erythematosus (SLE). METHODS: Seventy-one patients with mild SLE requiring < or = 10 mg of prednisone or equivalent daily and with arthritis or arthralgias were entered into a 48-week prospective, controlled, double blind multicenter trial and randomly assigned to either HCQ or Pl. RESULTS: Both HCQ and Pl were well tolerated in the 48-week trial. There were no remissions. With the exception of the patient assessment of joint pain, all other joint measures were similar between the groups. Twenty-nine patients withdrew before the end of the trial although only 2 patients withdrew for adverse drug effects. CONCLUSION: Our study found subjective pain relief as the only statistically significant difference in joint count variables from HCQ in the treatment of the articular manifestations of SLE.

Adult↗

PubMed1993

Comparison of naproxen and acetaminophen in a two-year study of treatment of osteoarthritis of the knee.

OBJECTIVE: To compare the relative safety and efficacy of naproxen and acetaminophen in the treatment of osteoarthritis (OA) of the knee. The major outcome measures were radiographic progression and withdrawal from the trial due to lack of efficacy. METHODS: One hundred seventy-eight patients with OA of the knee were enrolled in a 2-year prospective, controlled, double-blind multicenter trial and were randomly assigned to receive acetaminophen (ACT) or naproxen (NPX) treatment. RESULTS: After 6 weeks of treatment, modest improvement in pain on motion and in physician's global assessment was seen in both the ACT and the NPX groups, and the NPX group also had modest improvement in pain at rest and in 50-foot walk time. Sixty-two patients completed the 2-year study. Among these patients, radiographic progression was similar in the 2 treatment groups. Withdrawal from the trial due to lack of drug efficacy was slightly more frequent among patients in the ACT group (22% versus 16%), but withdrawal due to adverse drug effects was slightly more common in the NPX group (23% versus 18%). CONCLUSION: The efficacy of ACT treatment and NPX treatment was similar, although it was slightly better for NPX. The toxicity rate was slightly lower with ACT. However, the high rate of withdrawal in both treatment groups suggests that neither is satisfactory for the treatment of OA.

Acetaminophen↗

PubMed1992

Misclassification of exposure in a case-control study: the effects of different types of exposure and different proxy respondents in a study of pancreatic cancer.

This investigation addressed three questions about misclassification in a case-control study of risk factors for pancreatic cancer in which all exposure data were obtained from proxy respondents. These questions were: (1) To what degree was misclassification dependent on the type of exposure? (2) To what degree did misclassification vary by the type of proxy? (3) What was the magnitude of the effect of proxy misclassification on odds ratios measured across several levels of exposure? To answer these questions, we interviewed 163 control (index) subjects and next-of-kin (proxy) respondent pairs. Each of the controls and their respective proxies reported the control's use of coffee, cigarettes, and alcohol and weekly exposure to beef, milk, bacon, fruits, and vegetables. Nonspouse proxies misclassified exposures more than spouse proxies with the exception of cigarettes. Cigarette use was the most accurately reported exposure, followed by alcohol, coffee, and foods. For nondifferential misclassification between cases and controls, the slope of a dose-response curve was decreased from 6.6% to 100% depending on the exposure and the type of proxy respondent. Investigators conducting studies using proxy respondents need to recognize that misclassification is a function of multiple factors, including both the type of exposures under study and the type of proxies available.

Adult↗

PubMed1991

Dose volume histogram analysis of lung radiation from chest wall treatment: comparison of electron arc and tangential photon beam techniques.

The technique of electron arc irradiation of the post-mastectomy chest wall was developed to improve dose uniformity and to reduce lung irradiation in comparison to that seen with standard chest wall tangent photon beam methods. Because of the cephalocaudal variation in chest wall shape and thickness, electron arc treatment planning requires anatomical detail provided by multiple axial CT images of the thorax. To compare the fixed beam and rotational techniques, computer simulated beams covering the chest wall and internal mammary lymphatics were retrospectively applied to the CT-derived contours obtained during treatment planning for 12 consecutive patients receiving adjuvant chest wall treatment by electron arc. The lung dose distribution for each technique was calculated using heterogeneity corrections. The multiplanar 2-dimensional isodose distributions were summed to provide estimated 3-dimensional dose distributions of integral histograms. These reveal that for most of these patients a modest to large improvement in volume-dose relationship occurs with the electron arc technique.

Breast Neoplasms↗

PubMed1990

Analysis of improvement in individual rheumatoid arthritis patients treated with disease-modifying antirheumatic drugs, based on the findings in patients treated with placebo. The Cooperative Systematic Studies of Rheumatic Diseases Group.

A composite index for estimating improvement in individual rheumatoid arthritis (RA) patients during trials of slow-acting, disease-modifying antirheumatic drugs (DMARDs) was developed by analyzing the responses of 130 placebo-treated participants in Cooperative Systematic Studies of Rheumatic Diseases studies. If responses in 4 of 6 selected measures were required for improvement (by greater than or equal to 20% for morning stiffness, Westergren erythrocyte sedimentation rate, joint pain/tenderness score, and joint swelling score, and by greater than or equal to 2 grades on a 5-grade scale, or from grade 2 to grade 1 for patient's and physician's overall assessments of current disease severity), few placebo-treated patients qualified as improved, whereas significantly more DMARD-treated patients demonstrated improvement. The proposed index appears to be useful in estimating the probability that an RA patient will improve if taking a placebo during a DMARD trial, and may be a useful tool for analysis of DMARD studies.

Anti-Inflammatory Agents↗

PubMed1989

Diet and survival of patients with colon cancer in Utah: is there an association?

The extent to which diet influenced colon cancer survival was examined in 411 colon cancer cases identified in Utah between 1976 and 1981 using data from two population based case-control studies. After adjustment by proportional hazards regression models for the effects of tumour stage, age, sex, and religion, the hazard rate ratios (HRR) comparing highest to lowest quartile of intake for total calories, fat and protein were 0.60, 0.81 and 0.66 respectively, with the effect of calories being greatest for short-term survival (less than or equal to 24 months), HRR = 0.49. By contrast, the highest quartile of dietary fibre intake was associated with decreased survival (HRR = 1.53) when compared with the lowest quartile. More extensive studies are needed to verify these findings and to identify mechanisms underlying these associations.

Adult↗

PubMed1988

Method for probing cells in radiation-induced G2 arrest: demonstration of potentially lethal damage repair.

Chinese hamster ovary cells were arrested in the G2 phase of the cell cycle by X-irradiation. When subsequently treated with 5 mM caffeine the arrested population progressed into mitosis as a synchronous cohort where it was harvested by mitotic cell selection. This procedure provides a means to isolate cell populations treated in G2, for the investigation of G2 arrest. Comparisons were made of the number of cells retrieved from G2 arrest with the number suffering arrest, as determined by flow cytometry and by matrix algebraic simulations of irradiated cell progression. The retrieved population was not significantly less than expected for doses up to 3.5 Gy, indicating that the retrieval process does not favour the isolation of any population subset below this dose. Cell populations retrieved from arrest at varying intervals (0-3 h) after irradiation (0-3.5 Gy) showed an increase in survival with increase in interval, consistent with repair of potentially lethal damage. The repair curves (surviving fraction vs time) were each described by a single exponential. G2 cells that were brought to mitosis without a period of arrest exhibited the same radiation response as cells irradiated in mitosis.

Animals↗