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Biomedical subjects

J Fix

Publications and source records attributed to J Fix.

7 recordsLinked to original sources

Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries.

OBJECTIVES: To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental, occupational, and medical diagnostic exposures. DESIGN: Multinational retrospective cohort study of cancer mortality. SETTING: Cohorts of workers in the nuclear industry in 15 countries. PARTICIPANTS: 407 391 workers individually monitored for external radiation with a total follow-up of 5.2 million person years. MAIN OUTCOME MEASUREMENTS: Estimates of excess relative risks per sievert (Sv) of radiation dose for mortality from cancers other than leukaemia and from leukaemia excluding chronic lymphocytic leukaemia, the main causes of death considered by radiation protection authorities. RESULTS: The excess relative risk for cancers other than leukaemia was 0.97 per Sv, 95% confidence interval 0.14 to 1.97. Analyses of causes of death related or unrelated to smoking indicate that, although confounding by smoking may be present, it is unlikely to explain all of this increased risk. The excess relative risk for leukaemia excluding chronic lymphocytic leukaemia was 1.93 per Sv (< 0 to 8.47). On the basis of these estimates, 1-2% of deaths from cancer among workers in this cohort may be attributable to radiation. CONCLUSIONS: These estimates, from the largest study of nuclear workers ever conducted, are higher than, but statistically compatible with, the risk estimates used for current radiation protection standards. The results suggest that there is a small excess risk of cancer, even at the low doses and dose rates typically received by nuclear workers in this study.

Dose-Response Relationship, Drug↗

Effects of low doses and low dose rates of external ionizing radiation: cancer mortality among nuclear industry workers in three countries.

Studies of the mortality among nuclear industry workforces have been carried out, and nationally combined analyses performed, in the U.S., the UK and Canada. This paper presents the results of internationally combined analyses of mortality data on 95,673 workers (85.4% men) monitored for external exposure to ionizing radiation and employed for 6 months or longer in the nuclear industry of one of the three countries. These analyses were undertaken to obtain a more precise direct assessment of the carcinogenic effects of protracted low-level exposure to external, predominantly gamma, radiation. The combination of the data from the various studies increases the power to study associations between radiation and specific cancers. The combined analyses covered a total of 2,124,526 person-years (PY) at risk and 15,825 deaths, 3,976 of which were due to cancer. There was no evidence of an association between radiation dose and mortality from all causes or from all cancers. Mortality from leukemia, excluding chronic lymphocytic leukemia (CLL)--the cause of death most strongly and consistently related to radiation dose in studies of atomic bomb survivors and other populations exposed at high dose rates--was significantly associated with cumulative external radiation dose (one-sided P value = 0.046; 119 deaths). Among the 31 other specific types of cancer studied, a significant association was observed only for multiple myeloma (one-sided P value = 0.037; 44 deaths), and this was attributable primarily to the associations reported previously between this disease and radiation dose in the Hanford (U.S.) and Sellafield (UK) cohorts. The excess relative risk (ERR) estimates for all cancers excluding leukemia, and leukemia excluding CLL, the two main groupings of causes of death for which risk estimates have been derived from studies of atomic bomb survivors, were -0.07 per Sv [90% confidence interval (CI): -0.4, 0.3] and 2.18 per Sv (90% CI: 0.1, 5.7), respectively. These values correspond to a relative risk of 0.99 for all cancers excluding leukemia and 1.22 for leukemia excluding CLL for a cumulative protracted dose of 100 mSv compared to 0 mSv. These estimates, which did not differ significantly across cohorts or between men and women, are the most comprehensive and precise direct estimates of cancer risk associated with low-dose protracted exposures obtained to date. Although they are lower than the linear estimates obtained from studies of atomic bomb survivors, they are compatible with a range of possibilities, from a reduction of risk at low doses, to risks twice those on which current radiation protection recommendations are based.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

Comparison of costs of new atherectomy devices and balloon angioplasty for coronary artery disease.

The in-hospital cost for 126 consecutive patients undergoing 1-vessel, single-lesion coronary atherectomy (atherectomy group) beginning January 1, 1991, was reviewed (65 directional, 44 rotational, and 17 extractional atherectomies), and compared with the cost for 126 consecutive patients matched by sex and age who underwent 1-vessel, single-lesion standard balloon coronary angioplasty (angioplasty group). The in-hospital cost for each patient was determined using charges divided by a correction factor for each hospital department involved. Six different cost fields were created. The overall cost/charge ratio was 0.72. Angiographic and clinical success was 91% and 90% in the angioplasty group and 93% and 90% in the atherectomy group, respectively. Patients who underwent angioplasty required 1.3 +/- 0.6 devices/procedure, as compared with those who underwent atherectomy (2.4 +/- 1 devices/procedure) (p < 0.0001). The mean cost of angioplasty was $7,301 +/- $4,637 and of atherectomy devices $9,345 +/- $8,856 (28% increase). The difference was principally related to an increase in cost of supplies: angioplasty $2,028 +/- $1,196 versus atherectomy $3,632 +/- $1,525 (79% increase). There were no significant differences in hospitalization cost, procedure-room cost, and pharmacy and laboratory costs. Thus, higher risk morphologic lesions can be approached with new atherectomy devices with clinical and complication rates similar to coronary angioplasty. However, these results were obtained at a 28% increase in cost.

Angioplasty, Balloon, Coronary↗

Do patients with less than 'echo-perfect' results from mitral valve repair by intraoperative echocardiography have a different outcome?

BACKGROUND: Not all valve repairs for mitral regurgitation (MR) have a perfect result, with no MR on postpump intraoperative echocardiography. Although more than 2+ MR by postpump echocardiography has led to second pump runs for further surgery in 6% to 8% of our patients, those left with 1+ or 2+ MR, traditionally an acceptable result, have not previously been evaluated for clinical outcome. METHODS AND RESULTS: Among 530 patients undergoing mitral repair during 1987 to 1989, 76 patients with 1+ or 2+ MR by postpump intraoperative echocardiography were compared with 76 patients who had equivalent age, sex, left ventricular function, and concomitant surgery but who had no MR by postpump echo. In-hospital morbidity measured by the frequency of respiratory complications, strokes, time in intensive care unit, and duration of hospital stay was actually higher in the patients with no MR after repair. Hospital mortality was not significantly different. There were no significant differences in posthospital mortality (4-year survival estimate of 86% in both groups), thromboembolic events, hospitalizations for heart failure, or functional class, although more patients in the group with no MR after repair were using diuretics. There was a trend toward more reoperations in patients with 1+ or 2+ MR compared with those with no MR by intraoperative echocardiography after repair (4-year estimates of freedom from reoperation, 83% versus 94%; adjusted risk ratio, 3.30). CONCLUSIONS: The presence of 1+ or 2+ MR by postpump intraoperative echocardiography does not confer increased morbidity or mortality. However, the trend toward more reoperations suggests the need for close follow-up for possible recurrence of MR. These data support our low threshold for performing further surgery during second pump runs.

Female↗

Sapphire ring constriction syndrome.

An uncommon case of a partially embedded ring under the skin is presented. A technique for removal is described. All previously reported cases as well as ours occurred in mentally handicapped individuals.

Adult↗