Statistical analysis of historical occupational dose records at a large medical center

Routine monitoring of occupational radiation exposure is done primarily to demonstrate compliance with dose limits. Statistical analysis of past and present dose records provides a useful tool in the management of institutional radiation safety programs. In this study, a statistical analysis of annual dose records from 1985-1999 from a large tertiary care medical center with a cyclotron and radiopharmaceutical production facility is performed. A total of 6,089 annual dose records, categorized into ten occupational groups, were included in the analysis. Dose distribution is skewed, with 85% of workers receiving an annual dose of less than 1.0 mSv, while 1.3% have doses > or =10 mSv. The mean annual dose of all monitored workers during this 15-y period ranged from 0.5 to 1.2 mSv. Large variation in the mean annual dose exists among the different occupational groups. Four occupational groups were identified as relatively highly exposed, namely cyclotron and radiopharmaceutical production, cardiac catheterization, nuclear medicine, and diagnostic radiology. These four occupational groups also showed different trends in the mean annual dose. A correlation study showed that total annual collective dose has no linear association with the number of monitored workers, the number of measurably exposed workers, or the number of workers with annual dose between 0.1 to <10 mSv. Moderate correlation (r = 0.64) was observed between the annual collective dose and the collective dose of workers with an annual dose between 0.1 to <10 mSv. A strong and significant correlation (r = 0.95) exists between the total annual collective dose and both the number of workers with annual dose of > or =10 mSv and the corresponding collective dose due to these highly exposed workers. Although the fraction of these highly exposed workers is small (about 1%), they have a significant impact on the total collective dose and their contribution can be as high as 50%. Workers with annual dose of > or =10 mSv tend to concentrate in a few identified occupational groups and not across all occupational groupings. The cyclotron and radiopharmaceutical production department is of particular concern due to its high individual dose levels and increasing mean annual dose trend for the last 5 y. Radiochemists and cyclotron engineers tend to receive an annual dose exceeding the dose limit. A plot of the collective dose of highly exposed workers vs. the total collective dose shows that if a dose constraint of 10 mSv is imposed on highly exposed occupational groups, the total collective dose is expected to be about 200 person-mSv.     

Serum intercellular adhesion molecule-I in children with chronic liver disease: relationship to disease activity

Intercellular adhesion molecule-I (ICAM-I) is a member of the immunoglobulin supergene family. It is expressed on the surface membrane of cells of multiple lineages at sites of inflammation. A soluble form of ICAM (sICAM-I) comprising the five extracellular Ig-like domains of ICAM-I has been detected in human serum and has been found to be increased in a variety of acute and chronic liver disorders. However, little is known about sICAM-I levels in children with chronic liver disease. Therefore, we measured sICAM-I in 23 children with chronic hepatitis, 14 children with cirrhosis, and 10 age- and sex-matched normal children by commercially available ELISA. We also correlated the sICAM-I levels with the histological activity index (HAI) score as determined from liver biopsies. Patients with chronic hepatitis had higher sICAM-I levels compared to controls (723 ± 272 ng/ml vs 282 ± 43 ng/ml, mean ± sd; P < 0.05). sICAM-I levels were also higher in patients with cirrhosis compared to controls (630 ± 218 ng, mean ± sd; P < 0.05). However, there was no significant difference between sICAM levels in patients with chronic hepatitis and cirrhosis. A significant correlation was found between the ICAM-I level and the histological activity index score in patients with chronic hepatitis (r = 0.58; P < 0.001) and in patients with cirrhosis (r = 0.7; P < 0.001). We also found that by using the cutoff level of 346 ng/ml, sICAM-I can be used as a screening test with high specificity (100%) and sensitivity (94%) to differentiate children with chronic liver disease from normal children. We conclude that sICAM is increased in children with chronic hepatitis and cirrhosis compared to controls. The degree of elevation correlates with the HAI score. sICAM may be used as a marker of the disease activity and may provide diagnostic and prognostic information in children with chronic liver disease. However, this needs to be further studied.     

Angiogenic factors for the prediction of pre-eclampsia in women with abnormal midtrimester uterine artery Doppler velocimetry

OBJECTIVE: To determine whether assessing uterine perfusion and angiogenic factors concurrently in the second trimester improves the prediction of pre-eclampsia and intrauterine growth restriction (IUGR). METHOD: Plasma levels of soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) were measured for 108 women with abnormal uterine perfusion on Doppler velocimetry in the 23rd week. Later, 33 cases of pre-eclampsia and 9 of IUGR developed. RESULTS: Compared with the plasma levels of the women whose pregnancies remained normal, sFlt-1 levels were significantly higher and PlGF levels significantly lower in the women whose pregnancies became complicated by pre-eclampsia and/or IUGR (P<0.001). The alterations were more pronounced in cases of early-onset pre-eclampsia and in cases of IUGR that necessitated delivery before 34 weeks. Using the sFlt-1/PlGF ratio, these complications could be predicted with 98% sensitivity, 95% specificity, and 93% positive predictive value. CONCLUSION: Measuring uterine perfusion and angiogenic factors concurrently in the second trimester improved the prediction of pre-eclampsia and IUGR.     

Prolonged effectiveness of Norplant(R) capsule implants: a 7-year study

Soft tubing Norplant(R) contraceptive implants were studied in 1210 women for 7 years to measure the duration of effectiveness and the magnitude of the pregnancy rates over that time. Mean age at enrollment was 27.4 years. Of the enrollees, 42% were US residents. One-sixth (16.1%) weighed >/=70 kg at the time of implant placement. At the end of 5 years, the cumulative pregnancy rate was 1.1/100; at the end of 7 years, it was 1.9/100. No pregnancies occurred to any of the 400 women who enrolled in the study at age >/=30 years and who weighed <100 kg. Among women aged 18-33 years, the 7-year Norplant pregnancy rates are comparable to the median pregnancy rates of tubal sterilization methods for women of the same age and duration of use. For women aged >/=34 years, without regard to weight at admission, the 7-year effectiveness of soft tubing Norplant equals or surpasses that of tubal sterilization. For continuing implant users, annual pregnancy rates <1.0/100 in years 6 and 7, together with low cumulative pregnancy rates, testify that Norplant capsule implants remain highly effective for 7 years.     

Dimensional and architectural disproportion between the intrauterine device and the uterine cavity. A casue of bleeding

Hysterograms were performed on 172 women fitted with 30 mm Lippes Loops to determine uterine dimensions. Uteri classifications were: normal; triangular, divided into 1) small triangle, 30 mm. loop was too large; 2) medium triangle, device fits snugly, less severe bleeding at 7 months; 3) large triangle, device too small, mild bleeding at 10 months and formal conical cavity, divided into 1) narrow fundus, too small for device, leading to traumatic bleeding; 2) medium, device fits snugly causes intermenstrual bleeding; 3) large, loop covers only a portion of uterine cavity, bleeding less severe later. Ideally the IUD should fit snugly against the various borders of the uterine cavity, exerting light and equal pressure. Congenital anomalies and devices incorrectly positioned caused intermenstrual bleeding.     

Critical appraisal of the clinical and pathologic predictors of survival after resection of large hepatocellular carcinoma

HYPOTHESIS: A subset of patients with hepatocellular carcinoma (HCC) with a diameter of 10 cm or larger may benefit from hepatic resection. DESIGN: Retrospective study of a multi-institutional database. SETTING: Five major hepatobiliary centers. PATIENTS: We identified 300 patients who underwent hepatic resection for HCC 10 cm or larger. MAIN OUTCOME MEASURES: Clinical and pathologic data were collected, and prognostic factors were evaluated by univariate and multivariate analyses. Patient survival was stratified according to a clinical scoring system and pathologic T classification. RESULTS: The perioperative mortality rate was 5%. At a median follow-up of 32 months, the median survival was 20.3 months, and the 5-year actuarial survival rate was 27%. Four clinical factors-alpha-fetoprotein of 1000 ng/mL or higher, multiple tumor nodules, the presence of major vascular invasion, and the presence of severe fibrosis-were significant predictors of poor survival (all P<.05). Patients were assigned a clinical score according to the following risk factors: 1, no factor; 2, one or two factors; or 3, three or four factors. On the basis of the clinical score, patients could be stratified into only 2 distinct prognostic groups: no factor (score of 1) vs 1 or more factors (score of 2 or 3) (P<.001). In contrast, when patients were stratified according to pathologic T classification, 3 distinct groups were identified: T1 vs T2 vs T3 and T4 combined (P<.001). Fifty-six percent of the patients with a clinical score of 2 and 20% of patients with a clinical score of 3 actually had T1 or T2 disease on pathologic examination. CONCLUSIONS: Patients with large HCCs should be considered for liver resection as this treatment is associated with a 5-year survival rate exceeding 25%. Clinical predictors should not be used to exclude patients from surgical resection because these factors do not reliably predict outcome.