Best leads in the standard electrocardiogram for the emergency detection of acute coronary syndrome

BACKGROUND AND PURPOSE

The purpose of this study was to determine which leads in the standard 12-lead electrocardiogram (ECG) are the best for detecting acute coronary syndrome (ACS) among chest pain patients in the emergency department.

METHODS

Neural network classifiers were used to determine the predictive capability of individual leads and combinations of leads from 862 ECGs from chest pain patients in the emergency department at Lund University Hospital.

RESULTS

The best individual lead was aVL, with an area under the receiver operating characteristic curve of 75.5%. The best 3-lead combination was III, aVL, and V2, with a receiver operating characteristic area of 82.0%, compared with the 12-lead ECG performance of 80.5%.

CONCLUSIONS

Our results indicate that leads III, aVL, and V2 are sufficient for computerized prediction of ACS. The present results are likely important in situations where the 12-lead ECG is impractical and for the creation of clinical decision support systems for ECG prediction of ACS.

Road traffic noise in southern Sweden and its relation to annoyance, disturbance of daily activities and health

OBJECTIVES

This study investigated residential noise from road traffic and its relation to annoyance, disturbance of daily activities, and general health.

METHODS

A large public health survey in southern Sweden in 1999-2000 supplied data (N=13 557; 54% participation rate) on the demography, annoyance, and disturbance of daily activities, and on general health problems regarding concentration, sleep, stress, and treatment for hypertension. Residential road noise exposure was assessed with a geographic information system. Associations with 24-hour equivalent (average) and maximum road noise level were investigated for all participants and for selected subgroups using the Cochran-Armitage trend test and Cox regression analysis.

RESULTS

Annoyance from road traffic noise and the disturbance of daily activities increased markedly with road noise exposure. More than 25% reported at least occasional disturbance from traffic noise during relaxation and sleep in the highest exposure category for each noise measure. No overall pattern between road noise exposure and general health problems emerged. Among the participants that reported annoyance from road traffic noise (N=623), the average road noise level was associated with concentration problems (P for trend = 0.03) and with treatment for hypertension (P for trend = 0.02). Positive associations between average road noise exposure and health problems were found among females (hypertension), persons born outside Sweden (sleep), the unemployed (stress), and participants that reported financial problems (concentration problems).

CONCLUSIONS

Exposure to road traffic noise at high levels was common and produced frequent disturbances of daily activities. Negative health effects from road traffic noise were observed in important subgroups. The findings are of concern for southern Sweden, as well as for other regions with similar or higher traffic intensity.

Comparison between neural networks and multiple logistic regression to predict acute coronary syndrome in the emergency room

OBJECTIVE

Patients with suspicion of acute coronary syndrome (ACS) are difficult to diagnose and they represent a very heterogeneous group. Some require immediate treatment while others, with only minor disorders, may be sent home. Detecting ACS patients using a machine learning approach would be advantageous in many situations.

METHODS AND MATERIALS

Artificial neural network (ANN) ensembles and logistic regression models were trained on data from 634 patients presenting an emergency department with chest pain. Only data immediately available at patient presentation were used, including electrocardiogram (ECG) data. The models were analyzed using receiver operating characteristics (ROC) curve analysis, calibration assessments, inter- and intra-method variations. Effective odds ratios for the ANN ensembles were compared with the odds ratios obtained from the logistic model.

RESULTS

The ANN ensemble approach together with ECG data preprocessed using principal component analysis resulted in an area under the ROC curve of 80%. At the sensitivity of 95% the specificity was 41%, corresponding to a negative predictive value of 97%, given the ACS prevalence of 21%. Adding clinical data available at presentation did not improve the ANN ensemble performance. Using the area under the ROC curve and model calibration as measures of performance we found an advantage using the ANN ensemble models compared to the logistic regression models.

CONCLUSION

Clinically, a prediction model of the present type, combined with the judgment of trained emergency department personnel, could be useful for the early discharge of chest pain patients in populations with a low prevalence of ACS.

Gadolinium contrast media are more nephrotoxic than iodine media. The importance of osmolality in direct renal artery injections

A study was undertaken of the role of osmotoxicity in gadolinium (Gd) and iodine contrast media (CM) nephrotoxicity in ischemic porcine kidneys. Test solutions: mannitol iso-osmotic to 0.5 M: gadopentetate (1.96 Osm/kg H2O), 0.5 M: gadodiamide (0.78 Osm/kg H2O) and 0.5 M: iohexol (190 mg I/ml, 0.42 Osm/kg H2O). Each solution was injected [3 ml/kg body weight (BW)] into the balloon-occluded (10 min) renal artery of eight left-sided nephrectomized pigs. The plasma half-life of a glomerular filtration rate (GFR) marker was used to compare their effects on GFR 1-3 h post-injection. The median half-lives of the GFR marker after injection of gadopentetate (1,730 min) and mannitol 1.96 Osm/kg H2O (2,782 min) did not differ statistically (P = 0.28), but were significantly longer than after all other solutions (P < 0.001). There was no significant difference (P = 0.06) between gadodiamide (218 min) and mannitol 0.82 Osm/kg H2O (169 min), while there was (P = 0.03) between iohexol (181 min) and mannitol 0.43 Osm/kg H2O (148 min). The difference between gadodiamide and iohexol was significant (P = 0.01). Reduction in GFR, as a marker of nephrotoxicity, induced by gadopentetate correlated with its high osmolality, while the effect of gadodiamide and iohexol may include chemotoxicity. Iohexol molecules were less nephrotoxic than the Gd-CM molecules and contain three-times the number of attenuating atoms per molecule.

A simple statistical model for prediction of acute coronary syndrome in chest pain patients in the emergency department

BACKGROUND

Several models for prediction of acute coronary syndrome (ACS) among chest pain patients in the emergency department (ED) have been presented, but many models predict only the likelihood of acute myocardial infarction, or include a large number of variables, which make them less than optimal for implementation at a busy ED. We report here a simple statistical model for ACS prediction that could be used in routine care at a busy ED.

METHODS

Multivariable analysis and logistic regression were used on data from 634 ED visits for chest pain. Only data immediately available at patient presentation were used. To make ACS prediction stable and the model useful for personnel inexperienced in electrocardiogram (ECG) reading, simple ECG data suitable for computerized reading were included.

RESULTS

Besides ECG, eight variables were found to be important for ACS prediction, and included in the model: age, chest discomfort at presentation, symptom duration and previous hypertension, angina pectoris, AMI, congestive heart failure or PCI/CABG. At an ACS prevalence of 21% and a set sensitivity of 95%, the negative predictive value of the model was 96%.

CONCLUSION

The present prediction model, combined with the clinical judgment of ED personnel, could be useful for the early discharge of chest pain patients in populations with a low prevalence of ACS.

The utility of the growth hormone (GH) releasing hormone-arginine test for diagnosing GH deficiency in adults with childhood acute lymphoblastic leukemia treated with cranial irradiation

CONTEXT

The insulin tolerance test (ITT) is the current standard diagnostic test for the diagnosis of adult GH deficiency (GHD), but alternative tests, such as the GHRH-arginine test, have been proposed.

OBJECTIVE

We investigated the sensitivity and specificity of the GHRH-arginine test using ITT as the gold standard in diagnosing GHD in a group of young adults treated with cranial irradiation (CRT) for childhood acute lymphoblastic leukemia (ALL). We estimated the positive and negative predictive values of the GHRH-arginine test among patients as well as a number of individual characteristics and therapy-related factors during both the GHRH-arginine test and ITT.

DESIGN

Forty-three young adults, treated for childhood ALL with 18-30 Gy CRT and chemotherapy, were studied, and comparison was made with matched controls.

RESULTS AND CONCLUSIONS

We evaluated four different cutoff levels for GHD in the GHRH-arginine test: 5, 7.5, 9, and 16.5 microg/liter. Using 7.5 microg/liter as the cutoff yielded high specificity (94%), but at the same time the sensitivity was only 66%, which leads to a low negative predictive value (27%). In contrast, a failed GH response to the GHRH-arginine test accurately reflects the presence of radiation-induced GHD, illustrated by a high positive predictive value (95% at 7.5 microg/liter). Only age at CRT and body mass index remained significant predictors of the peak GH during the GHRH-arginine test. Because a high proportion of GHD patients show a normal response to the GHRH-arginine test, it cannot be used reliably to exclude GHD in these patients. Complementary ITT is also warranted to confirm GHD in obese patients.

Model specification and unmeasured confounders in partially ecologic analyses based on group proportions of exposed

OBJECTIVES

The aim of this study was to quantify bias from a partially ecologic analysis due to (i) model misspecification and (ii) an unmeasured confounder, considering various scenarios that may occur in occupational and environmental epidemiology. A study with an aggregate exposure variable, PE, but with outcome, group membership, and covariates assessed individually is partially ecologic. In this paper, PE is the proportion exposed; PE can vary across geographic areas or occupational groups.

METHODS

Several hypothetical scenarios were considered, varying the baseline risk, the exposure effect, the exposure distribution across groups, the impact of the (unmeasured) confounder, and the confounder distribution across groups. First, confounding within groups was introduced. Thereafter, confounding between groups was introduced by co-varying PE and the confounder prevalence across the groups. The expected odds ratio (exposed versus unexposed) was calculated in two alternative models, the logistic regression and linear odds models, both with PE as the independent variable. Moreover, empirical data on noise exposure and sleeping disturbances were analyzed.

RESULTS

Compared with the logistic regression model, the linear odds model yielded a markedly less biased odds ratio (OR) when the outcome was rare (< or = 5% baseline risk). Confounding within groups resulted in marginal bias, whereas confounding between groups resulted in more pronounced bias.

CONCLUSIONS

A logistic regression analysis, with PE as an independent variable, can yield substantial model misspecification bias. By contrast, the linear odds model is valid when the outcome is rare. Confounding between groups should be of more concern than confounding within groups in partially ecologic analyses.

Simple cystatin C-based prediction equations for glomerular filtration rate compared with the modification of diet in renal disease prediction equation for adults and the Schwartz and the Counahan-Barratt prediction equations for children

BACKGROUND

Serum creatinine is the most commonly used marker for estimation of glomerular filtration rate (GFR). To compensate for its drawbacks as a GFR marker, several prediction equations including several parameters are being used, with the Modification of Diet in Renal Disease (MDRD), Schwartz, and Counahan-Barratt equations being the ones most widely accepted for estimation of relative GFR in mL x min(-1) x (1.73 m(2))(-1). The present study analyzes whether these GFR prediction equations for adults and children might be replaced by simple prediction equations based on plasma concentrations of cystatin C.

METHODS

Data from 536 patients (0.3-93 years), consecutively referred for determination of GFR by an invasive gold standard procedure, were used for the analysis. Calculations of bias (median percentage of error), correlation (adjusted R(2)), and percentage of estimates within 30% and 50% of measured GFR were used in the comparisons.

RESULTS

A cystatin C-based prediction equation using only concentration in mg/L and a prepubertal factor: GFR [mL x min(-1) x (1.73 m(2))(-1)] = 84.69 x cystatin C (mg/L)(-1.680) x 1.384 (if a child <14 years) assessed GFR equally well or better than the simplified MDRD, the Schwartz, and the Counahan-Barratt prediction equations for the adult (> or =18 years) and juvenile groups of the investigated cohort. Age did not influence the cystatin C-based prediction equation for adults, whereas gender did, but with a factor close to unity (0.948 for females).

CONCLUSION

A GFR prediction equation based solely on cystatin C (in mg/L) and a prepubertal factor might replace the simplified MDRD prediction equation for adults and the Schwartz and Counahan-Barratt prediction equations for children.

Constitutional short telomeres are strong genetic susceptibility markers for bladder cancer

Lack of functional telomeres can cause chromosomal aberrations. This type of genetic instability may promote tumorigenesis. We have investigated the association between mean telomere length in buccal cells (assessed with quantitative real-time PCR) and bladder cancer risk in a case-control study. Patients with bladder cancer displayed significantly shorter telomeres than control subjects (P = 0.001). Median telomere length ratio was 0.95 (range 0.53-3.2) for cases and 1.1 (0.51-2.4) for controls. Moreover, the adjusted odds ratio (OR) for bladder cancer was significantly increased in the quartile with the shortest telomere length OR = 4.5 [95% confidence interval (CI) 1.7-12]. It is known that oxidative stress, alkylation or UV radiation increases shortening of telomeres. Therefore, we also analyzed whether environmental and genetic factors associated with DNA damage, i.e. smoking and polymorphisms in the genes involved in the metabolism of genotoxic carcinogens (EPHX1, GSTA1, GSTM1, GSTP1, GSTT1, NAT1, NAT2 and NQO1) or DNA repair (APE1, NBS1, XPC, XPD, XRCC1, XRCC3 and XRCC4), could modify the association between telomere length and cancer risk. A clear effect of smoking and telomere length could be observed. Current smokers with short telomeres had more than six times as higher risk as non-smokers/former smokers with long telomeres (OR = 6.3, 95% CI 1.7-23). Lack of the biotransformation gene GSTM1 and short telomeres were associated with OR = 6.5 (95% CI 2.4-18), whereas homozygous carriers of 312Asn in the DNA repair gene XPD, with short telomeres, displayed an OR of 17 (95% CI 1.9-150). However, no significant interaction for cancer risk could be proven for telomere length, smoking and susceptibility genotypes of metabolizing and DNA-repairing genes.

Blood supply and oxidative metabolism in muscle biopsies of female cleaners with and without myalgia

OBJECTIVES

Pathomechanisms of work-related myalgia are poorly understood. Myalgia is thought to be caused by excitation of nociceptors present in the muscular tissue but not in the muscle fiber itself. Muscle contraction in combination with hypoxia is known to excite nociceptors. Morphologic analysis can contribute to the knowledge of the excitation of nociceptors. This study thoroughly examines the morphology of the trapezius muscle's capillary supply and signs of disturbed oxidative metabolism to understand their role in work-related myalgia.

METHODS

Surgical trapezius muscle biopsies were obtained from 25 female cleaners with long-standing work-related myalgia, 25 female cleaners without trapezius myalgia, and 21 healthy teachers. Enzyme and immunohistochemical stainings were performed to highlight fibers with aberrant intermyofibrillar patterns, indicating a disturbed oxidative metabolism (also known as moth-eaten fibers) and a disturbed capillary supply of different fibers.

RESULTS

A significantly lower number of capillaries per fiber area in cleaners suffering from myalgia compared with cleaners without trapezius myalgia was found. Moth-eaten fibers were found in the 3 groups, but these fibers were significantly more prevalent in the groups of cleaners than in the healthy teacher group.

CONCLUSION

This work indicates that the capillary supply of trapezius is affected in work-related trapezius myalgia. More studies are needed to understand possible mechanisms that would explain the occurrence of moth-eaten fibers.

Growth hormone deficiency predicts cardiovascular risk in young adults treated for acute lymphoblastic leukemia in childhood

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, and until recently prophylactic cranial radiotherapy (CRT) was important for achieving long-term survival. Hypothalamic-pituitary hormone insufficiency is a well-recognized consequence of CRT for childhood cancer. Another problem is increased cardiovascular risk, which has been shown in long-term survivors of other childhood cancers. In the only previously reported study on cardiovascular risk after childhood ALL, obesity and dyslipidemia were recorded in a small subgroup treated with CRT, compared with patients treated with chemotherapy. The mechanisms behind the increase in cardiovascular risk in survivors of childhood cancer are not clarified. The aim of the present study was to elucidate mechanisms of increased cardiovascular risk in former childhood ALL patients. A group of 44 ALL survivors (23 males, median age 25 yr, range 19-32 yr at the time of study) treated with CRT (median 24 Gy, 18-30 Gy) at a median age of 5 yr (1-18 yr) and chemotherapy were investigated for prevalence of GH deficiency and cardiovascular risk factors. Comparison was made with controls randomly selected from the general population and individually matched for sex, age, smoking habits, and residence. All patients and controls underwent a GHRH-arginine test, and patients with a peak GH 3.9 microg/liter or greater were further investigated with an additional insulin tolerance test. Significantly higher plasma levels of insulin (P = 0.002), blood glucose (P = 0.01), and serum levels of low-density lipoprotein cholesterol, apolipoprotein (Apo) B, triglycerides, fibrinogen, and leptin (all P <or= 0.05) were recorded among the ALL patients, compared with controls. Furthermore, the serum levels of high-density lipoprotein cholesterol (P = 0.03) and Apo A1 (P = 0.005) were significantly lower among the patients. Compared with controls, the patients had higher body mass index and waist to hip ratio, and body composition measured with dual-energy x-ray absorptiometry showed significantly higher fat mass and lower lean mass (P < 0.001). Forty of 44 ALL patients (91%) were considered GH deficient according to the insulin tolerance test and/or the GHRH-arginine test, and the rest were considered GH insufficient. In patients, peak GH during GHRH-arginine was significantly negatively correlated to total body fat mass measured with dual-energy x-ray absorptiometry (r = -0.48, P = 0.001), waist to hip ratio (r = -0.32, P = 0.03), plasma insulin (r = -0.49, P = 0.001), and leptin (r = -0.46, P = 0.002). Moreover, a significantly positive correlation was recorded with high-density lipoprotein cholesterol (r = 0.38, P = 0.012). Using Doppler echocardiography, a marked reduction in cardiac dimensions and performance (ejection fraction P < 0.001 and fractional shortening P = 0.01), compared with controls, was recorded. In conclusion, at a median 17 yr after treatment with CRT and chemotherapy in former childhood ALL patients, a significant increase in cardiovascular risk factors was recorded. We suggest that GH deficiency, induced by CRT, is a primary cause for this because strong correlations between the stimulated GH peak and several of the cardiovascular risk factors were observed.

Incorporating group-level exposure information in case-control studies with missing data on dichotomous exposures

In case-control studies with exposure data obtained from interviews, participation is an issue of concern. Use of external group-level exposure information, available for all cases and controls (including nonparticipants), can reduce participation bias and improve precision of effect estimates. Our methodologic investigation was motivated by a population-based case-control study on occupational exposures and leukemia. We assessed exposure using dichotomous data collected in interviews, and also using census data on past and current occupational groups for all subjects. Based on information from a job-exposure database, a group-level probability of exposure was assigned to each subject. We studied the performance of the iterative expectation-maximization method for estimating the odds ratio (OR) by using the individual-level exposure data on the interviewed participants together with the assigned group-level exposure probabilities for the nonparticipants. In each iteration, the expected numbers of exposed and unexposed among the nonparticipating cases and controls were calculated from their assigned exposure probabilities and, for the cases only, from the current OR estimate. We then estimated the OR based on the total (observed plus expected) numbers and repeated the procedure until convergence. The expectation-maximization method eliminated participation bias and improved precision for scenarios with error-free group-level exposures and individual-level exposure data missing at random conditional on disease status and group affiliation. We specifically addressed consequences of assigning erroneous exposure probabilities to the nonparticipating subjects. In such situations, the expectation-maximization method can produce biased estimates if the participation rates among the cases and controls differ substantially.

Prevalence of current and chronic pain and their influences upon work and healthcare-seeking: a population study

OBJECTIVE

To investigate the prevalence of current and chronic pain and their relationship to pain intensity, sex, age, income, employment status, citizenship, marital status, urban residence, occupational activity, and healthcare-seeking based on a representative sample from a Swedish county.

METHODS

A cross-sectional survey using a postal questionnaire was sent to a representative sample (n = 9952) of the target population (284,073 people, age 18-74 yrs) in a county (Ostergötland) in southern Sweden. A questionnaire was mailed and followed by 2 postal reminders if necessary.

RESULTS

The participation rate was 76.7% (n = 7637); nonparticipants were on average younger, male, and earned less money. The overall point prevalence of pain was 48.9%. The corresponding one-month period prevalence was 63.0%, and pain on several occasions during the previous 3 months was reported by 61.3% of participants. The prevalence of chronic pain (pain > 3 months) was 53.7%. Female sex, age, and sick leave/early retirement were generally of significant importance in the regressions of pain. No sex factor was found in the regressions of pain frequency and pain intensity. Chronic pain especially frequent and intensive pain showed clear associations with healthcare-seeking and occupational activity.

CONCLUSION

High prevalence of current pain (48.9%) and chronic pain (53.7%) were found in this community-based study. Being female, older, and on sick leave or early retirement were generally of significant importance in the regressions of pain. Chronic pain showed clear associations with healthcare-seeking and occupational activity, indicating considerable socioeconomic costs.

Duodenal adenomatosis in familial adenomatous polyposis

BACKGROUND

The prevalence of duodenal carcinoma is much higher in familial adenomatous polyposis (FAP) than in the background population, and duodenal adenomatosis is found in most polyposis patients.

AIMS

To describe the long term natural history of duodenal adenomatosis in FAP and evaluate if cancer prophylactic surveillance of the duodenum is indicated.

METHODS

A prospective five nation study was carried out in the Nordic countries and the Netherlands.

PATIENTS

A total of 368 patients were examined by gastroduodenoscopy at two year intervals during the period 1990-2001.

RESULTS

At the first endoscopy, 238 (65%) patients had duodenal adenomas at a median age of 38 years. Median follow up was 7.6 years. The cumulative incidence of adenomatosis at age 70 years was 90% (95% confidence interval (CI) 79-100%), and of Spigelman stage IV 52% (95% CI 28-76%). The probability of an advanced Spigelman score increased during the study period (p<0.0001) due to an increasing number and size of adenomas. Two patients had asymptomatic duodenal carcinoma at their first endoscopy while four developed carcinoma during the study at a median age of 52 years (range 26-58). The cumulative incidence rate of cancer was 4.5% at age 57 years (95% CI 0.1-8.9%) and the risk was higher in patients with Spigelman stage IV at their first endoscopy than in those with stages 0-III (p<0.01).

CONCLUSIONS

The natural course of duodenal adenomatosis has now been described in detail. The high incidence and increasing severity of duodenal adenomatosis with age justifies prophylactic examination, and a programme is presented for upper gastrointestinal endoscopic surveillance.

Effect of intravenous L-NMMA on nitric oxide production in collagenous colitis

BACKGROUND

Nitric oxide (NO) is greatly increased in the colon of patients with inflammatory bowel disease of different aetiology, including collagenous colitis. In man, NO can be generated from NO synthases as well as from non-enzymatic sources. The source of the NO found in luminal intestinal gas has not been exactly pinpointed. We investigated the effect of the NO synthase inhibitor L-NMMA on intestinal concentrations of NO in patients with clinically active collagenous colitis. In addition, we measured NO levels from the respiratory tract.

METHODS

Ten patients with active collagenous colitis were studied. NO levels were measured from the respiratory tract and in the rectum before and after i.v. administration of L-NMMA (7.5 mg/kg) using a chemiluminescence method.

RESULTS

Airway NO release decreased markedly, and mean arterial blood pressure increased in all patients following L-NMMA treatment. Basal rectal NO levels were high (median > 10000 ppb) and decreased markedly in 5 patients after L-NMMA. In contrast, NO levels remained completely unchanged or even increased in the other 5 patients.

CONCLUSION

Rectal levels of NO are greatly increased in patients with symptomatic collagenous colitis. Intravenous administration of an NO synthase inhibitor reduced rectal NO only in half of the patients despite clear evidence of effective systemic NO synthase inhibition. This could indicate alternative NOS-independent sources of intestinal NO in this disease.

Cytogenetic and morphologic subgroups of myelodysplastic syndromes in relation to occupational and hobby exposures

OBJECTIVES

This study investigated the association between occupational and hobby exposure and the risk of myelodysplastic syndromes (MDS) while focusing on differential patterns of clonal chromosome aberrations and morphologic subgroups.

METHODS

A case-referent study was conducted with 330 MDS patients investigated cytogenetically in 1976-1993 (cases) and matched referents. Telephone interviews with either the person or a next-of-kin were used. The participation rate of the cases and referents was 85% and 60%, respectively. Information was obtained from the next-of-kin more often for the cases (88%) than for the referents (26%). Occupational hygienists assessed the exposure using interview data on worktasks and hobbies. Associations with disease risk were evaluated for 10 exposures with a logistic regression analysis.

RESULTS

The investigated exposures were generally not associated with cytogenetically abnormal MDS. Effect estimates for specific cytogenetic or morphologic subgroups were generally imprecise. Occupational exposure to extremely low-frequency magnetic fields (EMF) was associated with MDS with a normal karyotype [odds ratio (OR) 2.0, 95% confidence interval (95% CI) 1.0-4.0]. The exposure-response association was consistent for intensity but inconclusive for duration. A decreased risk was observed for MDS, irrespective of karyotypic pattern, among farmers and farmhands (OR 0.53, 95% CI 0.35-0.81).

CONCLUSIONS

Cytogenetically abnormal MDS was generally not associated with occupational or hobby exposure to known or suspected genotoxic agents. However, exposure prevalences and intensities were low for several agents. An association was suggested between occupational exposure to EMF and MDS with a normal karyotype. Biases due to differential information quality and selective participation cannot be ruled out.

Worldwide survey among polyposis registries of surgical management of severe duodenal adenomatosis in familial adenomatous polyposis

BACKGROUND

The lifetime risk of developing duodenal cancer in familial adenomatous polyposis (FAP) is about 5 per cent. When and to what extent surgical intervention should be undertaken to prevent death from invasive carcinoma is controversial. The aim of this study was to determine the effectiveness of various surgical treatments for cancer and severe duodenal adenomatosis.

METHODS

A questionnaire was mailed to the members of the Leeds Castle Polyposis Group to obtain data on patients with FAP, treated for duodenal cancer or severe duodenal adenomatosis after 1990.

RESULTS

Sixty-nine patients were included. The indication for surgery was invasive cancer in 13 patients, of whom six died from metastatic disease. Fifty-six patients were initially treated for severe duodenal adenomatosis, five (9 per cent) of whom died from metastatic disease (P = 0.002). In surviving patients, adenomas recurred after ampullectomy (six of eight, at mean follow-up of 11 months), after duodenotomy with polypectomy (17 of 21, at mean 29 months) and after pancreatoduodenectomy (six of 25, at mean 47 months). None of six patients who underwent a pancreas-sparing duodenectomy had recurrence of adenoma (mean follow-up 11 months).

CONCLUSION

Surgery for duodenal adenomatosis should take place before endoscopic biopsy reveals invasive cancer. Even after extensive surgical procedures, small bowel adenomas may occur, emphasizing the need for chemoprevention.

Female fecundity before and after operation for familial adenomatous polyposis

BACKGROUND

Knowledge about the fertility of women suffering from familial adenomatous polyposis (FAP) is scarce and inconclusive. The purpose of this study was to investigate the fecundity of women with FAP before and after operation, and to compare the findings with those of a general population database and women with ulcerative colitis.

METHODS

A questionnaire concerning reproductive experiences and waiting times to pregnancy was sent to all 230 women on the polyposis registers in Denmark, Finland, Sweden and Norway in whom primary surgery had consisted of ileorectal anastomosis or ileal pouch-anal anastomosis. Data on the general population and women with ulcerative colitis came from an existing database. Cox regression and Kaplan-Meier plots were used for analysis.

RESULTS

The fecundity of women with FAP before operation and after colectomy with ileorectal anastomosis was similar to that of the general population. However, fecundity dropped to 54 per cent (P = 0.015) following proctocolectomy with ileal pouch-anal anastomosis, although it was greater than the postoperative fecundity of women with ulcerative colitis.

CONCLUSION

The significant reduction in female fecundity after ileal pouch-anal anastomosis should be communicated to young women with FAP before it is decided which surgical option to follow.

Pooled analysis of clinical and cytogenetic features in treatment-related and de novo adult acute myeloid leukemia and myelodysplastic syndromes based on a consecutive series of 761 patients analyzed 1976-1993 and on 5098 unselected cases reported in the literature 1974-2001

To ascertain the frequency of treatment-related acute myeloid leukemias and myelodysplastic syndromes (t-AML/t-MDS) in an unselected series, we have identified all adult cases analyzed in our department from 1976 to 1993. Further aims were to compare karyotypic features of t-AML/t-MDS with de novo AML/MDS, in our material as well as in 5098 unselected, cyto- genetically abnormal, published cases, and to analyze associations between type of prior therapy and karyotype. Among our 372 AML and 389 MDS, 47 (13%) were t-AML and 62 (16%) were t-MDS. Clonal abnormalities were significantly more common in t-AML and t-MDS than in de novo disease (68% vs 50%, P < 0.05 and 84% vs 45%, P < 0.001, respectively). Among the available 4230 AML and 1629 MDS (the present series and published cases), 14% were t-AML and 15% were t-MDS. In t-AML/t-MDS, the number of anomalies and the ploidy levels differed significantly from de novo cases, with complex and hypodiploid karyotypes being more common in t-AML/t-MDS. In t-AML, unbalanced changes in general, t(1;3), der(1;7), 3p-, -5, 5q-, -7, 7q-, t(9;11), t(11;19), t(11q23), der(12p), -17, der(17p), -18, and -21 were significantly more frequent than in de novo AML. In t-MDS, -5, -7, 7q-, 13q-, der(17p), and -18 were significantly more common. Type of prior treatment correlated significantly with number of anomalies in t-AML and with ploidy levels in t-AML/t-MDS. The frequencies of several aberrations varied with type of therapy, eg, 5q- was more frequent in radiotherapy-associated t-MDS, monosomy 7 was more common in t-AML and t-MDS after treatment with alkylators, and t(11q23) in t-AML was associated with topoisomerase II inhibitors. Abnormalities significantly more common in de novo disease were +8 as a sole anomaly, balanced changes in general, t(8;21), t(9;22), t(15;17), inv(16), and t(21q22) in AML, and -Y, 5q-, and 20q- as sole anomalies and +8 in MDS. The results emphasize the strong association between previous genotoxic exposure and karyotypic features.

Risk factors for cerebrovascular deaths in patients operated and irradiated for pituitary tumors

Vascular mortality, especially cerebrovascular disease (CVD), are the most pronounced cause of mortality in women with hypopituitarism. In a cohort of 342 patients operated and irradiated for pituitary tumors, 31 died from CVD (CVD patients) between 1952 and 1996. The study assessed whether the radiation regimens and duration of symptoms of hypopituitarism before operation differed between the 31 CVD patients and the 62 matched patients from the same cohort who had not died from CVD (control patients). Furthermore, the infarction/hemorrhage ratio, type of clinical stroke syndrome, and time to death after stroke were investigated in the CVD patients and in matched controls from the general population who had died from CVD (population controls). No significant differences in maximum or centrally absorbed dose, maximum or central biological equivalent dose, field size, or number of fraction were recorded between CVD and control patients. A significant difference in the duration of symptoms of hypopituitarism before operation was recorded, but only in women (P = 0.01). There were no significant differences in the infarction/hemorrhage ratio (P > 0.3) of lacunar or posterior circulation syndrome compared with middle cerebral artery syndrome with cortical features (P = 0.22) or the proportion of patients who died within the first month after stroke onset (60% vs. 59%, respectively) between CVD patients and population controls. In conclusion, no significant effect on CVD deaths could be detected for any radiation parameter. A long history of unsubstituted pituitary insufficiency may be a contributing factor to the very high CVD mortality among women. There were no indications of significant differences in type of stroke, clinical stroke syndromes, or stroke fatality between the CVD patients and the population controls.

Myosin heavy chain isoforms influence surface EMG parameters: a study of the trapezius muscle in cleaners with and without myalgia and in healthy teachers

The present study had two aims: (1) to investigate potential differences in proportion of myosin heavy chain isoforms in the trapezius muscle between female cleaners with and without trapezius myalgia and healthy teachers, and (2) to elucidate if myosin heavy chain composition and surface electromyogram (EMG) during an isokinetic endurance test of shoulder flexors are significantly related. The subjects were divided into three groups: (1) 25 female cleaners with diagnosed work-related trapezius myalgia; (2) 25 female cleaners without work-related trapezius myalgia; (3) a control group of 21 healthy female teachers who were not exposed to repetitive or static muscle work. All subjects performed a test involving150 forward flexions using an isokinetic dynamometer. During the test surface EMG was recorded from the trapezius muscle. Muscle samples were obtained from the descending part of the trapezius muscle. The fibre type area percentage based on ATPase staining and the proportions of different MHC isoforms as determined by gel electrophoresis. The trapezius was dominated by MHC I (71%), followed by MHC IIA (22-24%), and MHC IIX (5-7%); no significant differences between the three groups of subjects were found. The proportion of MHC I correlated negatively with MHC IIA ( r=-0.78; P<0.001) and MHC IIX ( r=-0.53; P<0.001). Significant correlations existed between the proportion of the MHC isoforms and the corresponding proportion of the fibre type area; 27-45% of the variance was explained. The multivariate analysis of the three groups of subjects revealed that MHC variables showed intercorrelations with EMG (both amplitude and frequency variables). However, the directions of the relationships differed among the three groups; the cleaners with myalgia and the teachers showed the greatest similarities in patterns. Intrinsic muscle properties appear to influence the frequency content of the EMG, which is in contrast to some of the theoretical models of the EMG. Our data could suggest that monotonous work such as professional cleaning can change the relationships between muscle structure and the frequency content of the EMG.

Estimating attributable fraction in partially ecologic case-control studies

Partially ecologic case-control studies combine group-level exposure data with individual-level data on disease status, group membership, and covariates. If the exposure measure is the exposure prevalence of various groups, the attributable fraction (AF; the estimated proportion of cases that are attributable to exposure) can be estimated by classifying all subjects in groups with exposure prevalence above zero as exposed. Such a threshold AF estimator ([AF]T) is unbiased in confounding-free situations if the threshold is 100% sensitive, but it might be imprecise. We propose an alternative AF estimator, [AF]L, for partially ecologic case-control studies under a linear model for the association between the exposure prevalence and the odds ratio. The proposed estimator can also be applied to situations in which covariate adjustment is necessary. [AF]T and [AF]L are compared with respect to precision and bias. [AF]L is also unbiased when the exposure prevalence is zero in the group(s) assessed as unexposed. Using [AF]L will consistently result in improved precision compared with [AF]T, although the results may not differ substantially. The 95% confidence intervals for both AF estimators show satisfactory coverage in bias-free exposure scenarios. Pronounced negative bias and decreased coverage result for both AF estimators even when small fractions (3-9%) of exposed subjects are included in the group assessed as unexposed.

Effects of systematic exposure assessment errors in partially ecologic case-control studies

BACKGROUND

In ecologic studies, group-level rather than individual-level exposure data are used. When using group-level exposure data, established by sufficiently large samples of individual exposure assessments, the bias of the effect estimate due to sampling errors or random assessment errors at the individual-level is generally negligible. In contrast, systematic assessment errors may produce more pronounced errors in the group-level exposure measures, leading to bias in ecologic analyses.

METHODS

We focus on effects of systematic exposure assessment errors in partially ecologic case-control studies. Individual-level information on disease status, group membership, and covariates is obtained from registries, whereas the exposure is a group-level measure obtained from an established exposure database. Effects on bias and coverage of 95% CI in various error situations are investigated under the linear risk model, using both simulated and empirical ecologic data on exposures that are binary at the individual level.

RESULTS

Our simulations suggest that the bias produced by systematic exposure assessment errors under the linear risk model is generally approximately equal to the ratio of the slope bias and the intercept bias in ordinary linear regression with measurement errors in the independent variable. Consequently, bias in either direction can occur. Exposure assessment errors that systematically distort the group-level exposure measures have more pronounced effects on bias and coverage than errors producing random fluctuations of the group-level measures, which imply bias towards the null.

CONCLUSIONS

The results indicate the need for careful consideration of potential effects of systematic distortions of the group-level exposure measures when constructing and applying group-level exposure databases, such as probabilistic job exposure matrices.

Effects of irradiation on intestinal cells in vivo and in vitro

The effects of irradiation on intestinal epithelial cells were analyzed in vivo and in vitro. The in vivo study was carried out on the rat small intestine and for the in vitro study the intestinal crypt cell-line IEC-6 was used. Rat intestine and IEC-6 cells were irradiated with X-ray doses ranging between 1-16 Gy. Energy-dispersive X-ray microanalysis was used for detection of the elemental changes in the cells. Cell morphology was investigated in the scanning electron microscope, DNA-synthesis by autoradiography of 3H-thymidine incorporating nuclei and proliferation by cell counting. Our results indicate that in vivo, in the crypt cells, the increasing doses of irradiation led to increased sodium and lowered potassium and phosphorus concentrations. Corresponding ion shifts were found in the irradiated IEC-6 cells. Cells continued to proliferate up to the dose of 8 Gy, although the proliferation rate became lower with increasing dose of irradiation. The increasing dose of irradiation significantly reduced DNA-synthesis (16 Gy decreased DNA-synthesis by 50%) which resulted in a complete inhibition of cell proliferation. Analysis of goblet cells also showed characteristic radiation-dependent elemental changes. Scanning electron microscopical investigation of cells in culture revealed that most of the control cells were flat and had rather smooth cell membranes. Irradiation led to the appearance of numerous different membrane manifestations (microvilli of varying length and distribution, and blebs). Frequency of differences in the topology of the cells was related to the dose of irradiation. Our study clearly demonstrates that even low doses of irradiation cause changes in the ionic composition of the cells and inhibit DNA-synthesis and cell proliferation. The effects observed in the crypt cells in vivo were the same as in the intestinal cell line in vitro, which indicates that IEC-6 cells can be used for investigation of side effects of radiation to the abdomen.

Periampullary adenomas and adenocarcinomas in familial adenomatous polyposis: cumulative risks and APC gene mutations

BACKGROUND & AIMS

Patients with familial adenomatous polyposis (FAP) have a high prevalence of duodenal adenomas, and the region of the ampulla of Vater is the predilection site for duodenal adenocarcinomas. This study assessed the risk of stage IV periampullary adenomas according to the Spigelman classification and periampullary adenocarcinomas in Swedish FAP patients screened by esophagogastroduodenoscopy (EGD). The genotype of patients with stage IV periampullary adenomas and periampullary adenocarcinomas was also investigated.

METHODS

A retrospective study of 180 patients screened by EGD in 1982-1999 was undertaken. Kaplan-Meier analysis was performed to evaluate cumulative risk. Mutation analysis was carried out in patients with periampullary adenocarcinomas diagnosed outside the screening program, in addition to patients in the screening group with stage IV periampullary adenomas and adenocarcinomas.

RESULTS

Periampullary adenoma stage IV was diagnosed in 14 patients (7.8%), with a cumulative risk of 20% at age 60 years. Periampullary adenocarcinoma was diagnosed in 5 patients (2.8%), with a cumulative risk of 10% at age 60. Three of the adenocarcinomas occurred in patients with stage IV periampullary adenomas compared with 2 in patients with less severe periampullary adenomatosis at screening (odds ratio, 31; 95% confidence interval, 4.6-215). Fifteen (88%) of the APC gene mutations were detected; 12 of these were located downstream from codon 1051 in exon 15.

CONCLUSIONS

The life time risk of severe periampullary lesions in FAP patients is high, and an association between stage IV periampullary adenomas and a malignant course of the periampullary adenomatosis is strongly suggestive. Mutations downstream from codon 1051 seem to be associated with severe periampullary lesions.

Are occupational, hobby, or lifestyle exposures associated with Philadelphia chromosome positive chronic myeloid leukaemia?

OBJECTIVES

To investigate a broad range of occupational, hobby, and lifestyle exposures, suggested as risk factors for Philadelphia chromosome positive (Ph+) chronic myeloid leukaemia (CML).

METHODS

A case-control study, comprising 255 Ph+CML patients from southern Sweden and matched controls, was conducted. Individual data on work tasks, hobbies, and lifestyle exposures were obtained by telephone interviews. Occupational hygienists assessed occupational and hobby exposures for each subject individually. Also, occupational titles were obtained from national registries, and group level exposure-that is, the exposure proportion for each occupational title-was assessed with a job exposure matrix. The effects of 11 exposures using individual data and two exposures using group data (organic solvents and animal dust) were estimated.

RESULTS

For the individual data on organic solvents, an effect was found for moderate or high intensity of exposure (odds ratio (OR) 3.4, 95% confidence interval (95% CI) 1.1 to 11) and for long duration (15-20 years) of exposure (OR 2.1, 95% CI 1.1 to 4.0). By contrast, the group data showed no association (OR 0.69, 95% CI 0.27 to 1.8; moderate or high intensity versus no exposure). For extremely low frequency electromagnetic fields (EMFs), only individual data were available. An association with long occupational exposure to EMFs was found (OR 2.3, 95% CI 1.2 to 4.5). However, no effect of EMF intensity was indicated. No significant effects of benzene, gasoline or diesel, or tobacco smoking were found. OR estimates below unity were suggested for personal use of hair dye and for agricultural exposures.

CONCLUSIONS

Associations between exposure to organic solvents and EMFs, and Ph+CML were indicated but were not entirely consistent.

Evaluation of occupational and leisure time exposure assessment in a population-based case control study on leukaemia

OBJECTIVES

To increase the credibility of retrospective exposure assessments. documentation of the procedures and presentation of measures on quality control is recommended. The aim of this study was to present and evaluate the procedures used in a case-control study on leukaemia.

METHODS

A series of 1,087 cases and matched controls were interviewed. Exposure assessments were performed for 13 occupational agents and ten leisure-time activities and the confidence of the assessments was coded. The exposure assessments were performed blind by three occupational hygienists. Ten percent of the interviews were reassessed by two of the three occupational hygienists.

RESULTS

The leisure-time activities contributed to a large extent to the overall prevalence of exposure. For organic solvents approximately 25% of the controls classified as exposed would be misclassified if leisure-time exposure were not considered. The proportions of subject assessments with low confidence were higher for next-of-kin than for in-person interviews. A negative correlation was seen between the proportions of assessments with low confidence and the reliability. A significant difference was seen in the inter-rater comparison between cases and controls when the reliability was calculated for each assessed period; no difference was seen for the subject assessments used for relative risk estimation.

CONCLUSION

When low-dose exposure in epidemiological studies are being assessed there is an obvious risk of misclassification if leisure-time activities are not included. Furthermore, the reliability of the assessments may suffer if next-of-kin interviews are used to a large extent. For cancers with poor prognoses, prospective studies are preferable to minimise possible information bias.

Smoking and acute myeloid leukemia: associations with morphology and karyotypic patterns and evaluation of dose-response relations

This case-control study of tobacco smoking and acute myeloid leukemia (AML), emphasizing specific associations with morphologic and cytogenetic subtypes, comprised smoking histories for 333 cases and 351 controls. Smoking status (ever smokers versus life-long non-smokers) showed no evident effect on AML risk. However, an effect of smoking was indicated at high cumulative smoking doses (pack-years), e.g. 40 pack-years was associated with an odds ratio (OR) of 1.5 [95% confidence interval (CI) 1.0-2.3]. Among morphologic subtypes, the smoking associated OR for acute erythroleukemia was 8.9 (95% CI 1.0-76). No clear associations between smoking and cytogenetic subtypes of AML were observed.

Decision analysis in the surgical treatment of patients with familial adenomatous polyposis: a Dutch-Scandinavian collaborative study including 659 patients

BACKGROUND AND AIMS

The choice of colorectal surgery in patients with familial adenomatous polyposis lies between the morbidity of proctocolectomy and ileum-pouch-anal anastomosis (IPAA) and the mortality from rectal cancer after total colectomy and ileorectal anastomosis (IRA). The aims of the present study were: (1) to assess the risk of dying from rectal cancer after IRA, (2) to compare the life expectancy between patients with an IRA and those with an IPAA, and (3) to investigate whether regular endoscopic examination of the rectum leads to detection of cancer at an earlier stage.

METHODS

Clinical and pathological data on 659 patients who underwent colectomy and ileorectal anastomosis were collected from four national polyposis registries-that is, in Denmark, Finland, Sweden, and the Netherlands. Data were analysed using survival analysis methods. Decision analysis was used to compare the life expectancy between patients with an IRA and those with an IPAA.

RESULTS

A total of 47 patients developed rectal cancer after IRA. The risk of dying from rectal cancer was 12.5% (95% confidence interval 7.1--17.9%) by age 65. Compared with IRA, IPAA would lead to an increase in life expectancy of 1.8 years. Seventy five per cent of patients with rectal cancer had a negative rectoscopy within 12 months before the diagnosis.

CONCLUSION

IRA is associated with substantial mortality due to rectal cancer. Follow up examinations of the rectum does not have sufficient preventive effect on morbidity and mortality of rectal cancer.

Outcome of primary and secondary ileal pouch-anal anastomosis and ileorectal anastomosis in patients with familial adenomatous polyposis

PURPOSE

The aim of this study was to present Swedish experiences of the ileal pouch-anal anastomosis in patients with familial adenomatous polyposis from the introduction in 1984. The study also compared the surgical and functional outcome of different anal continence preserving procedures: ileal pouch-anal anastomosis as primary surgery, ileal pouch-anal anastomosis as secondary surgery after colectomy and ileorectal anastomosis, and ileorectal anastomosis alone.

METHODS

The material comprises all 120 patients with familial adenomatous polyposis reported to the Swedish Polyposis Registry who had undergone prophylactic colorectal surgery, including those operated on because of colorectal cancer from 1984 until the end of 1996. Anal continence preserving surgery was performed on 102 patients: 20 had ileal pouch-anal anastomosis as primary surgery at a median age of 24.5 years, 39 had ileal pouch-anal anastomosis as secondary surgery at a median age of 34 years, and 43 had ileorectal anastomosis alone, at a median age of 26 years, because 6 of the initially ileorectal anastomosis-operated patients were converted to ileal pouch-anal anastomosis as secondary surgery. Surgical outcome was assessed on the basis of hospital records. A questionnaire was used to evaluate the functional outcome. Fisher's exact probability test was used for statistical analysis.

RESULTS

Complications occurred in 51 percent of the patients after ileal pouch-anal anastomosis: 40 percent after ileal pouch-anal anastomosis as primary surgery and 56 percent after ileal pouch-anal anastomosis as secondary surgery. When the previous ileorectal anastomosis was taken into account 67 percent of the patients suffered complications which was significantly more compared with ileal pouch-anal anastomosis as primary surgery. After ileorectal anastomosis, 26 percent had complications which was significantly less compared with all other procedures but ileal pouch-anal anastomosis as primary surgery. No cancer occurred after ileal pouch-anal anastomosis, either in the ileal pouch or in retained rectal mucosa, but two of the patients who had an ileorectal anastomosis developed rectal cancer. One pouch excision was performed compared with ten rectal excisions. Functional outcome did not differ between ileal pouch-anal anastomosis as primary surgery and ileal pouch-anal anastomosis as secondary surgery. However, ileorectal anastomosis-operated patients had significantly better bowel function with regard to nighttime stool frequency, continence and perianal soreness.

CONCLUSION

These findings indicate that major advantages of ileal pouch-anal anastomosis are the low excision rate and, so far, no cancer in the ileal pouch. Moreover, the surgical outcome of ileal pouch-anal anastomosis as primary surgery is not significantly different from that of ileorectal anastomosis. However, the good surgical and functional outcome of ileorectal anastomosis, despite the long-range prognosis including rectal cancer and excision risks, has to be taken into consideration when selecting patients with familial adenomatous polyposis for primary surgery.

Fibre type proportion and fibre size in trapezius muscle biopsies from cleaners with and without myalgia and its correlation with ragged red fibres, cytochrome-c-oxidase-negative fibres, biomechanical output, perception of fatigue, and surface electromyography during repetitive forward flexions

In the literature enlarged/increased cross-sectional area (CSA) of type I muscle fibres has been reported as a morphological mark of work-related localised myalgia in the descending part of the trapezius muscle of women. These studies did not use enough subjects or lacked an adequate control group. The recording of surface electromyograms (EMG) is central to the research field of work-related myalgia. However, the influence of intrinsic muscle properties such as the effect of muscle fibre distribution upon surface EMG has to be better understood in order properly to evaluate this method as a possible diagnostic and preventive tool. This study had two aims. Firstly, it investigated the muscle fibre distribution and CSA in work-related myalgia in trapezius muscles. Secondly, the multivariate relationships among muscle morphology and histochemistry [ragged-red (RR) fibres, and cytochrome-c-oxidase-negative-fibre changes] EMG, perceived fatigue, and biomechanical output of shoulder flexions were analysed. The raw data have been presented in an earlier study. The participants in this study were 25 female cleaners with work-related myalgia of the trapezius muscle and 25 female cleaners not experiencing work-related myalgia of this muscle. The control group comprised 21 healthy female teachers who had not been exposed to highly repetitive work or static muscle work. Smaller CSA of type II fibres were found in cleaners compared to teachers. In this study the CSA of type I fibres of the trapezius muscles associated with myalgia were no greater than in muscles without myalgia. The prevalence of RR fibres together with age, fibre type proportions, CSA and working as a cleaner correlated with the ability to relax as recorded electromyographically. The relative mean frequency of the EMG of the trapezius muscle correlated with the prevalence of RR fibres, but it did not correlate with the proportions and CSA of different fibre types. Low biomechanical outputs and low signal amplitude increases of the EMG during the test were associated with high proportions of type -IIB fibres. The smaller CSA of type II fibres in cleaners might have reflected a different muscle activation pattern due to different occupational demands in cleaners than in teachers. Morphological or histopathological variables can influence the three EMG variables investigated.

Plasma levels of persistent organohalogens and hormone levels in adult male humans

In this study the authors assessed the possible relationship between high dietary exposure to persistent organohalogens (OHS) through fatty fish from the Baltic Sea and hormone levels in adult men. Blood samples were drawn from 110 men who consumed varying amounts of fish (i.e., 0-32 meals per month) for analysis of plasma levels of 18 polychlorinated biphenyl (PCB) congeners, 5 hydroxy-PCBs, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)-ethane (p,p'-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE), hexachlorobenzene, and 2,2',4,4'-tetrabromodiphenyl ether. In addition, plasma levels of follicle-stimulating hormone, luteinizing hormone, prolactin, plasma thyrotropin, free and total T3, free and total T4, and free testosterone were analyzed. The authors adjusted for age, and the only significant associations that remained were negative correlations between 2,2',4,4'-tetrabromodiphenyl ether and plasma thyrotropin (p < .001), and between pentachlorophenol and follicle-stimulating hormone (p = .04). The authors expected that there would be some significant correlations that resulted from pure chance. High consumption of organohalogen-polluted fish did not appear to affect plasma concentrations of pituitary, thyroid, or testosterone hormone levels in male adults.

Abnormal nuclear shape in solid tumors reflects mitotic instability

Abnormalities in nuclear morphology are frequently observed in malignant tissues but the mechanisms behind these phenomena are still poorly understood. In this study, the relation between abnormal nuclear shape and chromosomal instability was explored in short-term tumor cell cultures. Mitotically unstable ring and dicentric chromosomes were identified by fluorescence in situ hybridization at metaphase and subsequently localized in interphase nuclei from five malignant soft tissue tumors. The vast majority (71 to 86%) of nuclear blebs, chromatin strings, and micronuclei contained material from the unstable chromosomes, whereas few (<11%) were positive for stable chromosomes. Nuclear morphology was also evaluated in fibroblasts and an osteosarcoma cell line exposed to irradiation. A linear correlation was found between the frequency of abnormalities in nuclear shape, on one hand, and cells with unstable chromosomes (r = 0.87) and anaphase bridge configurations (r = 0.98), on the other hand. The relation between nuclear shape and karyotypic pattern was investigated further in cultures from 58 tumors of bone, soft tissue, and epithelium. Blebs, strings, and micronuclei were significantly more frequent in tumors that contained rings, dicentrics, or telomeric associations than in those exhibiting only stable aberrations (P: < 0.001) and a positive correlation (r = 0.78) was found between the frequency of such nuclear abnormalities and the intratumor heterogeneity of structural chromosome aberrations. These results indicate that the formation of nuclear blebs, chromatin strings, and micronuclei in malignant tissues is closely related to the breakage-fusion-bridge type of mitotic disturbances. Abnormalities in nuclear shape may thus primarily be regarded as an indicator of genetic instability and intratumor heterogeneity, independent of cytogenetic complexity and the grade of malignancy.

Acute myeloid leukemia and clonal chromosome aberrations in relation to past exposure to organic solvents

OBJECTIVES

The effects of occupational and leisure-time exposures on the risk of acute myeloid leukemia (AML) were investigated with emphasis on clonal chromosome aberrations (CCA) and morphological subtypes.

METHODS

Consecutively diagnosed cases of AML (N=333) and 1 population referent per case were retrospectively included in the study. Information on worktasks, companies, and leisure-time activities was obtained with telephone interviews. Exposure probability and intensity were assessed by occupational hygienists. Associations were evaluated with logistic regression.

RESULTS

Exposure to organic solvents was associated with an increased risk of AML [low exposure: OR 1.5 (95% confidence interval (95% CI) 1.0-2.3, moderate-high exposure: OR 2.3 (95% CI 1.0-5.0)]. For exposure to solvents, but not to benzene, the OR was 1.2 (95% CI 0.69-2.0) for "low" and 2.7 (95% CI 1.0-7.3) for "moderate-high" exposure. The observed effects increased with intensity and duration of exposure. The estimated effects were higher for patients >60 years of age at the time of diagnosis. The effect of exposure to organic solvents was not differential with regard to morphology [except possibly erythroleukemia: OR 4.2, 95% CI 1.0-17 or the presence of CCA in general]. No increased risk for AML with complex CCA or with total or partial losses of chromosomes 5 or 7 were observed, but a higher risk was found for AML with trisomy 8 (OR 11, 95% CI 2.7-42) as the sole aberration.

CONCLUSIONS

Exposure to organic solvents was associated with an increased risk of AML. This association was not due to benzene exposure alone and may be modified by age. Furthermore, specific associations with trisomy 8, and possibly also erythroleukemia, were suggested.

Ileorectal anastomosis is appropriate for a subset of patients with familial adenomatous polyposis

BACKGROUND & AIMS

This study reevaluates the risk of rectal cancer and the frequency of subsequent proctectomy for nonmalignant causes in patients with familial adenomatous polyposis (FAP) who have undergone colectomy with ileorectal anastomosis (IRA). Potential risk factors for rectal cancer in this setting are also examined, and recommendations for the choice of surgical procedure are made.

METHODS

The national polyposis registries in Denmark, Finland, The Netherlands, and Sweden included 659 patients undergoing surgery with IRA in 1940-1997. Kaplan-Meier analysis and Cox regression analysis were performed to evaluate cumulative risk, survival, and predictive risk factors.

RESULTS

Rectal carcinoma was diagnosed in 47 patients, with a cumulative 40-year risk of 0.32. The cumulative risk according to chronologic age was 0.30 at age 60, and higher in patients undergoing surgery above age 25 (P = 0.0016). Chronologic age was the only independent risk factor (P = 0.0016). The cumulative 5-year survival rate after rectal carcinoma was 0.60. The apc mutation was known in 167 patients, of whom 7 had rectal cancer. The cumulative 40-year risk of secondary proctectomy was 0.70, and higher in patients with a mutation in codon 1250-1500 than outside this region (P = 0.005). However, all 7 rectal cancers were found in the latter group. None of the 18 patients with attenuated FAP (mutation in codon 0-200 or >1500) had a secondary proctectomy.

CONCLUSIONS

IRA is recommended in (1) young patients with few rectal adenomas and a family history of a mild phenotype and (2) patients with attenuated FAP (a mutation in codon 0-200 or >1500), provided there is acceptance of life-long rectal surveillance. Patients with many rectal polyps and/or a family history of severe polyposis should be offered a restorative proctocolectomy with an ileal pouch-anal anastomosis.

Influence of the consumption of fatty Baltic Sea fish on plasma levels of halogenated environmental contaminants in Latvian and Swedish men

We examined the influence of widely varied consumption of fatty fish from the Baltic Sea and of age on plasma concentrations of polychlorinated biphenyls (PCBs), polychlorobiphenylols (OH-PCBs), 2, 2-bis(4-chlorophenyl)-1,1,1-trichloroethane (4,4'-DDT), 2, 2-bis(4-chlorophenyl)-1,1-dichloroethane (4,4'-DDE), 2,2',4, 4'-tetrabromodiphenyl ether (BDE-47), hexachlorobenzene (HCB), and pentachlorophenol (PCP) in Latvian and Swedish men. Both age and fish consumption were significantly correlated with the concentrations of [sigman]PCB, [sigman]OH-PCB, 4,4'-DDE, 4,4'-DDT, and HCB. In the case of BDE-47, no significant relationship with age was observed, and fish consumption had the largest relative effect on plasma concentrations of this contaminant. This relationship may be a result of exposure to BDE-47 having been more recent than that of PCBs and DDE, or because the half-life of BDE-47 may be shorter than that of PCB and DDE. Latvian men demonstrated higher plasma levels of DDE and DDT but lower levels of [sigman]PCB and PCP than did Swedish men. The corresponding levels of HCB and BDE-47 were similar in both countries. The Spearman's rank correlation coefficient obtained by comparing the level of the metabolite 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) to the combined levels of its parent compounds, 2,3,3',4, 4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118), was higher than the median correlation coefficient obtained upon comparing the level of this metabolite to all other possible combinations of two PCB levels. No other increased correlation between metabolite and parent PCB concentration was observed.

Influence of the consumption of fatty Baltic Sea fish on plasma levels of halogenated environmental contaminants in Latvian and Swedish men

We examined the influence of widely varied consumption of fatty fish from the Baltic Sea and of age on plasma concentrations of polychlorinated biphenyls (PCBs), polychlorobiphenylols (OH-PCBs), 2, 2-bis(4-chlorophenyl)-1,1,1-trichloroethane (4,4'-DDT), 2, 2-bis(4-chlorophenyl)-1,1-dichloroethane (4,4'-DDE), 2,2',4, 4'-tetrabromodiphenyl ether (BDE-47), hexachlorobenzene (HCB), and pentachlorophenol (PCP) in Latvian and Swedish men. Both age and fish consumption were significantly correlated with the concentrations of [sigman]PCB, [sigman]OH-PCB, 4,4'-DDE, 4,4'-DDT, and HCB. In the case of BDE-47, no significant relationship with age was observed, and fish consumption had the largest relative effect on plasma concentrations of this contaminant. This relationship may be a result of exposure to BDE-47 having been more recent than that of PCBs and DDE, or because the half-life of BDE-47 may be shorter than that of PCB and DDE. Latvian men demonstrated higher plasma levels of DDE and DDT but lower levels of [sigman]PCB and PCP than did Swedish men. The corresponding levels of HCB and BDE-47 were similar in both countries. The Spearman's rank correlation coefficient obtained by comparing the level of the metabolite 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107) to the combined levels of its parent compounds, 2,3,3',4, 4'-pentachlorobiphenyl (CB-105) and 2,3',4,4',5-pentachlorobiphenyl (CB-118), was higher than the median correlation coefficient obtained upon comparing the level of this metabolite to all other possible combinations of two PCB levels. No other increased correlation between metabolite and parent PCB concentration was observed.

Mechanical performance and electromyography during repeated maximal isokinetic shoulder forward flexions in female cleaners with and without myalgia of the trapezius muscle and in healthy controls

This cross-sectional study aimed at investigating the influence of occupational exposure to static and highly repetitive work involving the neck and shoulder muscles, myalgia of and tender point in the trapezius muscle on biomechanical output, and electromyogram (EMG) variables (mean frequency MNF, signal amplitude and ability to relax) during maximal forward flexions of the shoulder muscles. Groups of 25 cleaners suffering from chronic myalgia of the trapezius muscle, 25 cleaners free from myalgia of the trapezius muscle and 21 teachers performed 150 forward flexions using an isokinetic dynamometer. Perception of fatigue was reported and surface EMG was recorded from four muscles during the endurance test. The cleaners were stronger than the teachers. Myalgia was associated with lower levels of endurance and a high degree of perceived fatigue. The ability to relax the trapezius muscle decreased with age and was even lower in cleaners with and without myalgia. Higher MNF of the deltoid muscle but not of the trapezius muscle was found in the group suffering from myalgia compared to the groups free from myalgia. This cross-sectional study indicated that myalgia of the trapezius muscle did not influence the strength but did influence the endurance of the forward flexor muscles of cleaners. The observed decrease in the ability to relax the trapezius muscle in cleaners compared to healthy teachers might be indicative of a future insufficiency in the muscle. Prospective studies are needed to define the significance of the results presented here.

Smoking and myelodysplastic syndromes

The purpose of this case-control study was to investigate tobacco smoking as a risk factor for myelodysplastic syndromes, emphasizing karyotypic aberrations as markers for exposure and risk differentiation with respect to morphology. We obtained smoking history by interview of 330 cytogenetically investigated adult myelodysplastic syndrome cases and 337 controls, matched with respect to sex, year of birth, and county of living. Smoking for at least 1 year at some time 20 years or less before diagnosis was associated with an elevated relative risk (RR) for primary myelodysplastic syndromes (odds ratio (OR) 1.8; 95% confidence interval (CI) = 1.2-2.7). The results indicated a relation with intensity and duration of smoking as well as a decrease in risk a few years after cessation of smoking. Smoking was associated with an increased RR for primary myelodysplastic syndromes with chromosome 7 abnormalities (OR 5.0; 95% CI = 1.1-23). Elevated RRs were also seen for refractory anemia (OR 2.5; 95% CI = 1.2-5.6) and for refractory anemia with ringed sideroblasts (OR 3.2; 95% CI = 0.88-12). The findings suggest that smoking is a risk factor for myelodysplastic syndromes.

The prevalences of cytochrome c oxidase negative and superpositive fibres and ragged-red fibres in the trapezius muscle of female cleaners with and without myalgia and of female healthy controls

The association of cytochrome c oxidase negative fibres (COX-negative) and ragged-red fibres (RR-fibres) with work related trapezius myalgia has been proposed. Hitherto studies have been small or without control groups. The aim of the present study was to investigate the prevalences of RR-fibres and COX-negative fibres in female cleaners with (n=25) and without (n=23) trapezius myalgia and in clinically healthy female teachers (n=21). The cleaners did mainly floor cleaning requiring monotonous loading on the trapezius muscle. A questionnaire covering background data and aspects of pain (prevalence, duration, intensity and influence on daily living) was answered. Biopsies were obtained from the trapezius muscle by an open surgical technique. The three groups did not differ in prevalence of COX-negative or COX-superpositive (i.e. type-I fibres with extremely strong brownish reaction in both the COX and SDH/COX stainings) fibres. The prevalence of COX-negative fibres was age dependent. Two subgroups of RR-fibres were present when stained for COX; COX-negative (73%) and COX-superpositive (26%) fibres. Forty-two percent of the COX-negative fibres were RR-fibres and 79% of the COX-superpositive were RR-fibres. A significantly (P=0.002) higher proportion of the COX-superpositive fibres in the cleaners were RR-fibres compared to the teachers. Multivariate regression analysis revealed that age, occupation as cleaner and a tender point in the trapezius were significantly associated with increased prevalences of RR-fibres; a cleaner with a tender point had a 4.35 higher prevalence of RR-fibres compared to a teacher without a tender point. No correlations between other pain related variables and prevalence of RR-fibres were noted. In conclusion, RR-fibres but not COX-negative or COX-superpositive fibres were correlated with cleaning work tasks and with a tender point in the trapezius.

Epidemiology of familial adenomatous polyposis in Sweden: changes over time and differences in phenotype between males and females

BACKGROUND

The Swedish Polyposis Registry was set up in Sweden in the late 1950s to promote screening of familial adenomatous polyposis (FAP). The aim of this study was to examine the epidemiology of FAP in Sweden, including the influence of screening on morbidity and mortality in colorectal cancer (CRC).

METHODS

Four hundred and thirty-one patients (213 males and 218 females) with FAP from 145 families recorded by the Swedish Polyposis Registry were investigated. The effect of screening on morbidity and mortality in CRC was evaluated by comparing the 216 probands with the 215 call-up patients. Three different periods were studied: the pre-screening period (1912-1956), the first screening period (1957-1976), and the second screening period (1977-1996).

RESULTS

The mean annual incidence rates during the three periods were 0.2, 1.38, and 0.86 per million, respectively. The birth frequency was calculated to be 1 in 18,000 between 1947 and 1966, and the prevalence was 32 per million at the end of 1996. The proportion of new mutants among the FAP patients born between 1927 and 1966 was estimated to be 11%. The median age at diagnosis of probands was 39 (range, 11-71) years and did not change over time, although an increase was seen in the subgroup with CRC at diagnosis (P = 0.02). In the call-up group the median age at diagnosis was 22 (range, 3-65) years. Sixty-seven per cent of the probands and 3.3% of the call-up patients had CRC at diagnosis, and the corresponding mortality figures were 44% and 1.9%. The risk among probands of having CRC at diagnosis decreased from 81% to 49% (P = 0.0006). Female probands were diagnosed with symptoms (P = 0.03) and CRC (P = 0.04) earlier than male probands.

CONCLUSIONS

A nationwide screening program facilitates detection and early diagnosis of FAP. A decrease in CRC morbidity among probands contributed to the improved prognosis. An earlier onset of symptoms and CRC in females indicate that the course of FAP is influenced by sex.

Familial adenomatous polyposis is associated with a marked decrease in alkaline sphingomyelinase activity: a key factor to the unrestrained cell proliferation?

The hydrolysis of sphingomyelin generates key molecules regulating cell growth and inducing apoptosis. Data from animal cancer models support an inhibitory role for this pathway in the malignant transformation of the colonic mucosa. In the intestinal tract, a sphingomyelinase with an optimum alkaline pH has been identified. We recently found that the activity of alkaline sphingomyelinase is significantly decreased in colorectal adenocarcinomas, indicating a potential anticarcinogenic role of this enzyme. To further examine whether the reduction of sphingomyelinase is present already in the premalignant state of neoplastic transformation, we measured sphingomyelinase activities in patients with familial adenomatous polyposis (FAP) and in sporadic colorectal tubulovillous adenomas. Tissue samples were taken from adenomas and surrounding macroscopically normal mucosa from 11 FAP patients operated with ileorectal anastomosis, from three FAP patients with intact colon, from 13 patients with sporadic colorectal adenomas and from 12 controls. Activities of acid, neutral and alkaline sphingomyelinase were measured together with alkaline phosphatase. In FAP adenoma tissue, alkaline sphingomyelinase activity was reduced by 90% compared to controls (P < 0.0001), acid sphingomyelinase by 66% (P < 0.01) and neutral sphingomyelinase by 54% (P < 0.05). Similar reductions were found in the surrounding mucosa. In sporadic adenoma tissue, only alkaline sphingomyelinase was reduced significantly, by 57% (P < 0.05). Alkaline phosphatase was not changed in FAP adenomas, but decreased in the sporadic adenomas. We conclude that the markedly reduced levels of alkaline sphingomyelinase activities in FAP adenomas and in the surrounding mucosa may be a pathogenic factor that can lead to unrestrained cell proliferation and neoplastic transformation.

The inhibitory effect in experimental autoimmune encephalomyelitis by the immunomodulatory drug Linomide (PNU-212616) is not mediated via release of endogenous glucocorticoids

The immunomodulatory drug Linomide (PNU-212616) is an efficient inhibitor of experimental autoimmune encephalomyelitis (EAE) and a variety of other models of autoimmunity. The mechanism of action of the drug is, however, incompletely resolved. It was recently suggested that Linomide might exert its immunomodulatory activity by stimulation of the hypothalamic-pituitary-adrenal axis. To investigate the relevance of this mechanism of action, we monitored the plasma levels of endogenous corticosterone after treatment with Linomide, and also directly compared the inhibitory activity of the drug on acute EAE induced in sham or adrenalectomized SJL/N mice. Treatment with Linomide resulted in a dose related inhibition of EAE in line with previously reported results. Upon onset of clinical signs of EAE, there was a 7-10 fold elevation of plasma corticosterone from the normal baseline level. Administration of Linomide did however not by itself result in any change in plasma corticosterone levels, neither at the pre-symptomatic phase of the disease nor during acute short term treatment. In adrenal ectomized animals immunized for EAE, paralytic disease developed rapidly and was of a more severe and fatal nature as compared to sham-operated controls. Treatment with Linomide had a profound inhibitory effect on development of paralytic disease in both the ectomized and sham-operated groups. These results strongly suggest that Linomide does not exert its immunomodulatory activity via the release of endogenous glucocorticoids.

Linomide suppresses experimental autoimmune neuritis in Lewis rats by inhibiting myelin antigen-reactive T and B cell responses

Linomide (quinoline-3-carboxamide) is a synthetic immunomodulator that suppresses several experimental autoimmune diseases. Here we report the effects of Linomide on experimental autoimmune neuritis (EAN), a CD4+ T cell-mediated animal model of acute Guillain-Barré syndrome (GBS) in humans. EAN induced in Lewis rats by inoculation with bovine peripheral nervous system (PNS) myelin and Freund's complete adjuvant was strongly suppressed by Linomide administered daily subcutaneously from the day of inoculation. Linomide dose-dependently delayed the interval between immunization and onset of clinical EAN, as well as the severity of EAN symptoms. These clinical effects were associated with dose-dependent down-modulation of PNS antigen-induced T and B cell responses and with suppression of the proinflammatory cytokines IL-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) mRNA. In PNS sections, Linomide suppressed IL-12 and TNF-alpha, and up-regulated IL-10 mRNA expression. These findings suggest that Linomide could be useful in certain T cell-dependent autoimmune diseases.

Linomide suppresses chronic-relapsing experimental autoimmune encephalomyelitis in DA rats

Linomide (quinoline-3-carboxamide) is a synthetic immunomodulator that suppresses several experimental autoimmune diseases. Here we report the effects of Linomide on chronic progressive and/or relapsing experimental autoimmune encephalomyelitis (PR-EAE), a CD4+ T cell mediated animal model of multiple sclerosis (MS). PR-EAE induced in DA rats by inoculation with homogenized guinea pig spinal cord and Freund's complete adjuvant, was strongly suppressed by Linomide administered daily subcutaneously from the day of inoculation. Linomide dose-dependently delayed the interval between immunization and onset of clinical PR-EAE, reduced severity and relapse of clinical PR-EAE, and shortened clinical PR-EAE. These clinical effects were associated with the down-modulation of CNS antigen-induced T cell responses and production of proinflammatory cytokines (IFN-gamma and TNF-alpha) as well as with upregulation of IL-4 (except in spleen MNC), IL-10 and TGF-beta in both spleen MNC and the spinal cord. These effects indicate that Linomide can suppress PR-EAE and may mediate its suppressive effects by regulation of cytokines.

Linomide suppresses acute experimental autoimmune encephalomyelitis in Lewis rats by counter-acting the imbalance of pro-inflammatory versus anti-inflammatory cytokines

Linomide (quinoline-3-carboxamide) is a synthetic immunomodulator that suppresses several experimental autoimmune diseases. Here we report the effects of Linomide on experimental autoimmune encephalomyelitis (EAE), a CD4+ T cell-mediated animal model of multiple sclerosis (MS). EAE induced in Lewis rats by inoculation with homogenized guinea pig spinal cord and Freund's complete adjuvant was strongly suppressed by Linomide administered daily subcutaneously from the day of inoculation. Linomide dose-dependently delayed the interval between immunization and onset of clinical EAE, and reduced severity of EAE symptoms. These clinical effects were associated with dose-dependent down-modulation of myelin antigens-induced T cell responses and by suppression of the proinflammatory cytokines IFN-gamma and TNF-alpha, and upregulation IL-4, IL-10 and TGF-beta as evaluated by in situ hybridization for mRNA expression in spleen mononuclear cells and spinal cord sections. These findings suggest that Linomide could be useful in certain T cell dependent autoimmune diseases.