Glutathione S-transferases M1, T1, and P1 and breast cancer

We examined associations for glutathione S-transferases M1 (GSTM1), T1 (GSTT1), and P1 (GSTP1) genotypes and breast cancer in the Carolina Breast Cancer Study, a population-based, case-control study in North Carolina. Odds ratios were close to the null value for each GST locus among African-American women (278 cases and 271 controls) and white women (410 cases and 392 controls), as well as pre- and postmenopausal women. For women with a history of breast cancer in one or more first-degree relatives, odds ratios were 2.1 (95% confidence interval, 1.0-4.2) for GSTM1 null and 1.9 (0.8-4.6) for GSTT1 null genotypes. Among women with a family history, age at diagnosis was significantly earlier for those with the GSTM1 null genotype. We did not observe strong evidence for modification of odds ratios for smoking according to GST genotypes. There was no evidence for combined effects of GSTM1, GSTT1, and GSTP1 genotypes, and there were no combined effects for GST genotypes and the catechol O-methyltransferase genotype. We conclude that GSTM1, GSTT1, and GSTP1 genotypes do not play a strong role in susceptibility to breast cancer. However, the role of GST genotypes in age at onset and risk of breast cancer among women with a family history merits further investigation.

Participation rates in a case-control study: the impact of age, race, and race of interviewer

PURPOSE

Despite concerns about declining participation rates in epidemiologic studies in recent years, relatively few papers have discussed obstacles to recruiting study participants or strategies for optimizing response rates. This report describes factors associated with nonparticipation in a population-based, case-control study of breast cancer and discusses ways to overcome barriers to participation.

METHODS

Contact and cooperation rates were calculated for participants in the Carolina Breast Cancer Study (CBCS), stratified by case status, age, race, and race of interviewer. Demographic and breast cancer risk factor characteristics of partial and full responders also were compared.

RESULTS

Contact rates and cooperation rates varied by case/control status and demographic characteristics. Contact rates were lower among controls, younger women, and black women. Cooperation rates were lower among controls, older women, and black cases. Cooperation rates were higher among both black and nonblack women when participants and interviewers were concordant on race.

CONCLUSIONS

Obstacles to recruitment seem to differ among race and age subgroups, suggesting that recruitment strategies may need to be tailored to potential participants based upon demographic characteristics. Strategies have been implemented to improve response rates in this and other epidemiologic studies; however, additional research and innovation in this area are needed.

P57 (KIP2) polymorphisms and breast cancer risk

A previous report in this journal has suggested that germline deletions in the proline-alanine-rich (PAPA-repeat) region of P57 (KIP2) are associated with increased risk of a variety of cancers, including breast cancer. We have analyzed the association of P57 PAPA-repeat deletion polymorphisms and breast cancer risk as part of a population-based case-control study of breast cancer. We have not observed an association between the presence of one or two copies of deletion polymorphisms in P57 and breast cancer risk (adjusted odds ratio: 1.1, 95% confidence interval: 0.6-2.0). Further investigation is necessary to determine the functional significance of P57 deletion polymorphisms and their potential relationship with disease.

Catechol-O-methyltransferase and breast cancer risk

Recent studies suggest that a polymorphism in catechol-O-methyltransferase (COMT) is associated with increased risk of breast cancer. Methylation by COMT is the principal pathway for inactivation of catechol estrogens, which are hypothesized to participate in estrogen-induced carcinogenesis. We examined the association of COMT genotype and breast cancer risk in a population-based, case-control study of invasive breast cancer in North Carolina. The study population consisted of 654 cases and 642 controls, with approximately equal numbers of African-American and white women and women under the age of 50 and aged 50 or over. Contrary to previous reports, we did not observe an association between one or more copies of the low activity COMT allele (COMT-L) and breast cancer risk. Multivariate relative risks (RRs) were 0.8 (95% confidence interval: 0.6-1.1) for COMT-HL and 0.8 (0.6-1.1) for COMT-LL, compared with the COMT-HH genotype. RRs for COMT did not differ among African-American and white women and we did not observe strong modification of RR estimates by menopausal status, body mass index, physical activity or other covariates. Our results suggest that COMT genotype is not related to breast cancer risk.

Cigarette smoking, N-acetyltransferases 1 and 2, and breast cancer risk

To examine the effects of smoking and N-acetylation genetics on breast cancer risk, we analyzed data from an ongoing, population-based, case-control study of invasive breast cancer in North Carolina. The study population consisted of 498 cases and 473 controls, with approximately equal numbers of African-American and white women, and women under the age of 50 and age 50 years or older. Among premenopausal women, there was no association between current smoking [odds ratio (OR), 0.9; 95% confidence interval (CI), 0.5-1.5] or past smoking (OR, 1.0; 95% CI, 0.6-1.6) and breast cancer risk. Among postmenopausal women, there was also no association with current smoking (OR, 1.2; 95% CI, 0.7-2.0); however, a small increase in risk was observed for past smoking (OR, 1.5; 95% CI, 1.0-2.4). For postmenopausal women who smoked in the past, ORs and 95% CIs were 3.4 (1.4-8.1) for smoking within the past 3 years, 3.0 (1.3-6.7) for smoking 4-9 years ago, and 0.6 (0.3-1.4) for smoking 10-19 years ago. Neither N-acetyltransferase 1 (NAT1) nor N-acetyltransferase 2 (NAT2) genotype alone was associated with increased breast cancer risk. There was little evidence for modification of smoking effects according to genotype, except among postmenopausal women. Among postmenopausal women, ORs for smoking within the past 3 years were greater for women with the NAT1*10 genotype (OR, 9.0; 95% CI, 1.9-41.8) than NAT1-non*10 (OR, 2.5; 95% CI, 0.9-7.2) and greater for NAT2-rapid genotype (OR, 7.4; 95% CI, 1.6-32.6) than NAT2-slow (OR, 2.8; 95% CI, 0.4-8.0). Future studies of NAT genotypes and breast cancer should investigate the effects of environmental tobacco smoke, diet, and other exposures.

Electrical occupations and neurodegenerative disease: analysis of U.S. mortality data

Investigators have hypothesized that occupations involving electric and magnetic field exposure are associated with a variety of health problems, including neurological disease. The authors conducted a case-control study, and they used U.S. death certificates with occupational coding to compare male cases of Alzheimer's disease (n = 256), Parkinson's disease (n = 168), and amyotrophic lateral sclerosis (n = 114) with controls matched for age and calendar time. The authors selected controls in a 3:1 ratio to cases from persons who died of causes other than leukemia, brain cancer, and breast cancer. Overall associations with electrical occupations were modest (i.e., adjusted odds ratios of 1.2, 1.1, and 1.3 for Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, respectively). Individual electrical occupations were associated more strongly with disease than overall electrical occupations, particularly amyotrophic lateral sclerosis, for which relative risks ranged from 2 to 5 across several job categories. The largest associations with all three diseases occurred for power plant operators.

Male and female occupation in relation to miscarriage and preterm delivery in central North Carolina

PURPOSE

This study was undertaken to evaluate the role of parental occupation in miscarriage and preterm delivery. Previous studies raise the possibility that both male and female exposures could affect pregnancy.

METHODS

Data from a population-based study of miscarriage and preterm delivery in central North Carolina were used to examine potential associations with male and female occupation. Medically treated miscarriage cases (n = 418), preterm delivery cases identified through hospital record review (n = 582), and term, normal birth weight controls (n = 787) were sought for telephone interview. The interview included information on jobs the woman held before and during the pregnancy, reports of her partner's job around the time of pregnancy, and information on potential confounding factors.

RESULTS

Female employment overall, or in specific jobs, around the time of conception or early pregnancy was not associated with the risk of miscarriage, whereas working during pregnancy, especially in the seventh month, was inversely associated with risk of preterm delivery. Male employment in several industrial occupations was weakly associated with miscarriage (adjusted odds ratios (OR) of 1.6 to 1.8), and somewhat more strongly associated with preterm delivery, particularly for chemists and sheet metal workers (adjusted OR over 3). Restriction to married men strengthened the associations.

CONCLUSIONS

Our results are limited by nonresponse, imprecision, incomplete identification of miscarriages, and lack of detailed occupational exposure information. Nonetheless, we found greater support for further examination of male compared to female jobs in relation to pregnancy outcome.

Male and female employment in the textile industry in relation to miscarriage and preterm delivery

To address potential reproductive hazards in textile manufacturing, we conducted a community-based case-control study in central North Carolina. Miscarriage cases were identified from medical records (280 interviewed cases): preterm delivery cases and term, normal birth weight controls (454 and 605, respectively) were identified from area hospitals. Exposures were based on job title, an interview concerning textile-related exposures, expert imputation of exposure based on job titles and interviews, and self-reported exposures by women. Relative to women and men working in nonhazardous occupations, workers in the textile industry were not at increased risk of miscarriage or preterm delivery, with the possible exception of preterm delivery among women and men employed in sectors other than knitting and yarn mills and men employed in yarn mills. Inferred exposures to specific agents were also not associated with adverse pregnancy outcome. Subject to uncertainty in exposure assessment and nonresponse, these data indicate an absence of adverse effects of the textile workplace environment on these pregnancy outcomes.

Cigarette smoking and semen quality

OBJECTIVE

To determine whether cotinine levels provide stronger evidence for an association between smoking and semen quality than the number of cigarettes smoked per day or years smoked controlling for potential confounders and effect modifiers.

DESIGN

Cross-sectional study.

SETTING

Male volunteers at the Reproductive Endocrinology-Fertility Laboratory.

PARTICIPANTS

Eighty-eight men (ages 18 to 35 years) provided a semen, urine, and blood specimen and completed a self-administered questionnaire concerning smoking and demographic information as well as caffeine and alcohol consumption. Urine, blood, and semen cotinine levels were analyzed via RIA.

MAIN OUTCOME MEASURE

Standard clinical semen analysis.

RESULTS

Number of cigarettes smoked per day, years smoked, and log-transformed cotinine levels were associated negatively with semen quality (density, total count, and motility). The association was evident among men age > or = 22 years. For example, the correlation coefficient for the overall association between logged urine cotinine and logged sperm density was -0.23; those stratified by age were 0. 13 (age < 22 years) and - 0. 39 (age > or = 22 years). Potential confounders included in regression models did not diminish the associations.

CONCLUSIONS

Smoking is associated with lowered semen quality.

Anxiety and depressive symptom identification using the Duke Health Profile

Duke Health Profile (DUKE) subscales were compared for their ability to identify anxiety and depressive symptoms as measured by the State Anxiety Inventory (SAI) and the Center for Epidemiologic Studies Depression Scale (CES-D) in 413 primary care patients. The seven-item Duke Anxiety-Depression Scale (DUKE-AD) was the best symptom identifier, with sensitivities and specificities greater than 70% for high scores on both the SAI and CES-D. Also, baseline DUKE-AD scores predicted five clinical outcomes during an 18-month follow-up period, with receiver operating characteristic (ROC) curve areas ranging from 57.1 to 58.7%. Patients shown by DUKE-AD scores to be at high risk (>30, scale 0-100) for symptoms of anxiety and/or depression were more often women, less well-educated, not working, and with lower socioeconomic status. The severity of illness was higher than that of low-risk patients. Although the providers did not know which patients were at high risk, they made a clinical diagnosis of anxiety or depression more often in high-risk patients.

Perceived family stress as a predictor of health-related outcomes

OBJECTIVE

To measure the predictive effect of patient-perceived family stress for health-related outcomes.

DESIGN

Prospective study of patients whose social stress and support were measured by self-report at baseline with the Duke Social Support and Stress Scale and used as predictors of outcomes during an 18-month follow-up period.

SETTING

Rural primary care community health clinic.

PATIENTS

Convenience sample of ambulatory adults.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Follow-up (one or more follow-up visits), frequent follow-up (more than six visits), referral and/or hospitalization (one or more), high follow-up severity of illness (upper-tertile mean Duke Severity of Illness Checklist scores), and high follow-up total charges (> or = $268).

RESULTS

There were 413 patients with a mean age of 40.4 years. Of these, 58.6% were women; 47.2%, African American; 52.8%, white; 56.7%, married; 77.2%, wage earners or housekeepers; and 52.3% had more than one health problem. At baseline, patients with high self-reported family stress (upper-tertile Duke Social Support and Stress Scale scores) had lower quality of life, functional health, and social support scores and higher dysfunctional health and social stress scores than other patients. High baseline family stress scores (scale of 0 to 100) predicted follow-up (odds ratio [OR] = 1.014), frequent follow-up (OR = 1.021), referral and/or hospitalization (OR = 1.018), high severity of illness at follow-up (OR = 1.016), and high follow-up charges (OR = 1.018) after controlling for the effects of social support, age, gender, and race. Family stress scores were stronger predictors of these outcomes than the other social stress and support variables.

CONCLUSION

The finding of patient-perceived family stress as a risk factor for unfavorable health-related outcomes suggests the need for early detection and treatment of family stress by family physicians.

Computer-prompted diagnostic codes

BACKGROUND

The purpose of this study was to develop and evaluate a computer system that would translate patient diagnoses noted by a physician into appropriate International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes and maintain a patient-specific up-to-date problem list.

METHODS

The intervention consisted of a computerized list (dictionary) of diagnoses, including practice-specific synonyms and abbreviations, linked to their corresponding ICD-9-CM codes. To record the diagnoses for the office visit before the intervention, physicians used International Classification of Health Problems in Primary Care (ICHPPC-2) codes. After the intervention, physicians used their own words or checked previously identified diagnoses on the computer-generated problem list. The computer then identified the correct ICD-9-CM code. Accuracy of coding was compared before and after the new computerized system was implemented.

RESULTS

Visits in which all diagnoses matched increased from 58% to 76% (P < .001) with use of the computer system. Visits in which no computer diagnoses matched the chart decreased from 22% to 8% (P < .001). Errors of omission declined from 38% to 18% (P < .001). Errors of commission decreased from 19% to 11% (P = .006). Overall accuracy increased from 62% to 82% (P < .001).

CONCLUSIONS

Outpatient medical diagnosis coding can be simplified and accuracy improved by using a computerized dictionary of practice-specific diagnoses and synonyms linked to appropriate ICD-9-CM codes. Such a system provides a computer-generated problem list that accurately reflects the chart and assists with prompted coding on subsequent visits.

Assessing Impact of Weight on Quality of Life

This paper is a preliminary report on the development of a new instrument, the Impact of Weight on Quality of Life (IWQOL) questionnaire, that assesses the effects of weight on various areas of life. We conducted two studies utilizing subjects in treatment for obesity at Duke University Diet and Fitness Center. The first study describes item development, assesses reliability, and compares pre- and post-treatment scores on the IWQOL. In the second study we examined the effects of body mass index (BMI), gender, and age on subjects' perceptions of impact of weight on quality of life. Results indicate adequate psychometric properties with test-retest reliabilities averaging .75 for single items, and .89 for scales. Scale internal consistency averaged .87. Post-treatment scores differed significantly from pre-treatment scores on all scales, indicating that treatment produced positive changes in impact of weight on quality of life. The results of the second study indicate that the impact of weight generally worsened as the patients' size increased. However for women there was no association between BMI and impact of weight on Self-Esteem and Sexual Life. Even at the lowest BMI tertile studied, women reported that weight had a substantial impact in these areas. There were also significant gender differences, with women showing greater impact of weight on Self-Esteem and Sexual Life compared with men. The impact of age was a bit surprising, with some areas showing positive changes and others showing no change.

Health status and severity of illness as predictors of outcomes in primary care

Two measures of health status and severity of illness were tested as indicators of patient case-mix to predict health-related outcomes in a rural primary care community health clinic, using a convenience sample of 413 ambulatory adults (mean age = 40.4 years: 58.6% women, and 47.2% black). At baseline; patients completed the Duke Health Profile, and providers completed the Duke Severity of Illness Checklist. During the 18-month follow-up study, patients experienced the following outcomes: at least one follow-up visit (74.3%), more than six visits (20.6%), at least one referral or hospital admission (17.3%), upper tertile severity scores (24.9%), and upper tertile office charges (24.9%). Baseline physical health, perceived health, and severity scores were statistically significantly predictive of all five outcomes. Predictive accuracy (i.e., area under the receiver operating characteristic curves) for outcome probabilities estimated from a case-mix model of physical health, severity, age, gender, and race was 72.3% for follow-up, 69.7% for frequent follow-up, 70.5% for referral and/or hospital stay, 65.7% for high follow-up severity of illness, and 67.6% for high follow-up charges. These data support health status and severity of illness as case-mix indicators and outcome predictors of follow-up utilization, severity of illness, and cost in the primary care setting.

Disease-specific versus generic measurement of health-related quality of life in insulin-dependent diabetic patients

The health-related quality of life of 170 adult insulin-dependent diabetic patients was measured cross-sectionally to compare a disease-specific instrument, Diabetes Quality of Life (DQOL) questionnaire, and two generic instruments, the Duke Health Profile (DUKE) and the General Health Perceptions Questionnaire (GHP). The generic measures provided as much or more information about health-related quality of life as the disease-specific instrument. This was demonstrated both by comparison of the DQOL with the DUKE and GHP and by comparison of the disease-specific with the generic components of a modified version of the DQOL. Patients with the diabetic complication of nephropathy had increased worry over their health and lower general health perceptions. Neither the duration of diabetes nor the intensity of insulin therapy, however, was found to have a statistically significant effect on any of the health-related quality of life scores. Nondiabetic factors, such as the comorbidity, nondiabetic medications, marital status, social relationships, and family arguments were found to be predictors of health-related quality of life more often than the diabetic factors duration of diabetes, complications, and intensity of insulin therapy. These analyses suggest the clinical value of using generic questionnaires to measure health-related quality of life and psychosocial factors to identify nondiabetic problems that might respond to intervention, thereby potentially enhancing the effect of diabetes-specific therapy.

The Duke Severity of Illness Checklist (DUSOI) for measurement of severity and comorbidity

The Duke Severity of Illness Checklist (DUSOI) was evaluated on 414 primary care adult patients using data collected both by medical providers at the time of the patient visit and later by a chart auditor. Severity scores for individual diagnoses were determined by summing the ratings for four non-disease-specific parameters: symptom level, complications, prognosis without treatment, and expected response to treatment. Mean diagnosis severity scores (scale 0-100) among the 21 most prevalent diagnoses varied from a low of 13.9 for menopausal syndrome to a high of 43.0 for sprains and strains. An overall severity score was calculated by combining diagnosis severity scores and giving highest weights to the most severe diagnoses. Provider-generated overall severity scores (mean = 43.3) and auditor-generated overall severity scores (mean = 38.9) were significantly correlated (coefficient of agreement = 0.59, p < 0.0001). Diagnoses varied in their individual contribution to the overall severity score, from 8.9% for lipid disorder to 90.0% for sprains and strains. Separate comorbidity severity scores were calculated to measure the severity of all of each patient's health problems except the diagnosis under study. For example, patients with menopausal syndrome had co-existing health problems which generated a high mean comorbidity severity score of 43.2, while patients with sprains and strains had a low mean comorbidity score of 4.7. The DUSOI Checklist can be used in the clinical setting by both providers and auditors to produce quantitative severity scores (by diagnosis, overall, and for comorbidity) which are based entirely upon clinical judgment. This method should be useful in controlling for severity of illness in clinical studies and indicating the outcome of medical care in terms of reduction in severity of illness following medical interventions.

Increasing compliance with mammography recommendations: health assessment forms

BACKGROUND

Inexpensive reminder systems are needed to ensure that primary care physicians consistently provide health maintenance services to their patients. The purpose of this study was to determine the effectiveness of a simple, inexpensive health assessment form in place of the standard chart note to increase physician compliance with mammography recommendations.

METHODS

A health assessment form with a reminder for screening mammography was implemented in a family practice in 1987 and was to be used as the official chart record for health maintenance visits. The charts of all women 50 years of age and older with two or more office visits during the years 1985 through 1988 were audited to determine how many mammograms were completed. Results were compared with mammography completion rates at a similar practice that did not use a health assessment form.

RESULTS

The study group showed a significant increase in mammography completion after implementation of the form, with compliance increasing from 7.3% to 32.0% (P < .001). The comparison group had an increase in mammogram completion from 12.0% to 17.8% (P < .001). The difference between the changes in rates of mammography in the two practices was statistically significant (P < .001). Among women in the study group who had a scheduled health maintenance visit during the study period the average rate of mammography completion increased from 21.2% to 65.2% (P < .001).

CONCLUSIONS

The addition of a health assessment form with a mammography reminder at the health maintenance visit is an effective and inexpensive method to increase compliance with mammography.

Quality of life and functional health of primary care patients

Quality of life and functional health were measured cross-sectionally for 314 adult ambulatory primary care patients in a rural clinic and found to be much better for patients with low severity of illness who required no confinement to home because of health problems, than for patients with high severity of illness who required confinement. Severity of illness was the strongest predictor for patient-reported physical health function and for patient quality of life when assessed by the health provider. Confinement was the strongest predictor for patient quality of life when assessed by the patient. There was very little agreement between patient-assessed and provider-assessed quality of life. Family stress was the strongest predictor of function in terms of mental health, social health, general health, self-esteem, anxiety, and depression. These data suggest that clinicians should direct increased attention to patient-assessed quality of life, patient-reported functional health status, and psychosocial factors such as family stress in an effort to improve medical outcomes.

Development of the 17-item Duke Health Profile

The 17-item Duke Health Profile (DUKE) was developed as a refined version of the 63-item Duke-UNC Health Profile (DUHP) using a methodology based upon a balanced clinical and statistical rationale. The result is a brief, valid functional health measure with 10 scales that compares well with the MOS Short-form and the COOP Charts. In addition to the five constructs (ambulation, emotional symptoms, activities with friends or relatives, health perception, and pain) which are measured by all three of the instruments, the DUKE quantitates cognition, social self-esteem, confinement, and somatic symptoms other than pain.

Validation of the Duke Social Support and Stress Scale

The Duke Social Support and Stress Scale (DUSOCS) was validated in 249 adult family practice patients using the Family Strengths, the Family Inventory of Life Events, and the Duke Health Profile (DUKE) as comparison instruments. Validity was supported in that the DUSOCS family support measure had the clinically expected positive associations with DUKE health measures (regression coefficients of +7.4 to +18.7) and negative associations with DUKE anxiety and depression measures (-2.0 to -17.2). DUSOCS family stress had negative associations with the health measures (-11.6 to -34.5) and positive associations with anxiety and depression (+18.9 to +32.1). Family and non-family stress contributed more than severity of illness to elevated levels of anxiety and depression and lowered levels of mental health, social health, and self-esteem, while these same stresses contributed only half as much as severity of illness to lowered physical health.

The Duke Health Profile. A 17-item measure of health and dysfunction

The Duke Health Profile (DUKE) is a 17-item generic self-report instrument containing six health measures (physical, mental, social, general, perceived health, and self-esteem), and four dysfunction measures (anxiety, depression, pain, and disability). Items were derived from the 63-item Duke-UNC Health Profile, based upon face validity and item-remainder correlations. The study population included 683 primary care adult patients. Reliability was supported by Cronbach's alphas (0.55 to 0.78) and test-retest correlations (0.30 to 0.78). Convergent and discriminant validity were demonstrated by score correlations between the DUKE and the Sickness Impact Profile, the Tennessee Self-Concept Scale, and the Zung Self-Rating Depression Scale. Clinical validity was supported by differences between the health scores of patients with clinically different health problems. Patients with painful physical problems had a DUKE physical health mean score of 58.1, while patients with only health maintenance problems had a mean score of 83.9 (scale: 0.0 = poorest health and 100.0 = best health). Patients with mental health problems had a DUKE mental health mean score of 49.2, in contrast to 75.7 for patients with painful physical problems and 79.2 for those with health maintenance. The DUKE is presented as a brief technique for measuring health as an outcome of medical intervention and health promotion.

The health status and life satisfaction of first-year medical students

The self-reported health status and life satisfaction of 286 first-year Duke University medical students in four consecutive classes were measured at the beginning and end of the school year and compared statistically with relevant sociodemographic and behavioral factors. Health status, quantitated in terms of Duke Health Profile scores, was generally lower for women than for men. Although there was a definite trend of worsening along all parameters of health and satisfaction during the year for both women and men, the most marked change was the increase in depressive symptoms. The students who were very satisfied with life had fewer symptoms of depression and anxiety; higher self-esteem, better physical, mental, and social health; stronger social ties; more physical activity; more sleep; and fewer stressful life events. Strong social ties was the factor most positively related to better health and life satisfaction.

Acetylcholinesterase antibodies and thyroid autoimmunity

It has been suggested that anti-thyroglobulin antibodies cross-react with acetylcholinesterase (AChE) and that this may explain the pathogenesis of Graves' ophthalmopathy. We have tested this hypothesis using an ELISA. Antibodies to human red blood cell AChE were found in 21% of 47 patients with thyroid autoimmunity. However antibodies to AChE were also detected in one of 25 normal subjects and two of 16 patients with non-organ specific autoimmunity. The anti-AChE antibodies showed no correlation with anti-thyroglobulin antibody levels and they were not associated with the presence of severe ophthalmopathy. Inhibition studies suggested only limited cross reactivity, if any, between anti-Tg and anti-AChE antibodies. Immunoblotting demonstrated antibody binding to at least four human AChE determinants at 130, 55, 32 and 22 kD. Our results demonstrate quite frequent anti-AChE reactivity in sera but no relationship with the development of orbital pathology.

Actions of beta-bungarotoxin on spontaneous release of transmitter at muscle end-plates treated with botulinum toxin

Rat leg muscles were injected subcutaneously with sublethal doses of type A botulinum neurotoxin, and the extensor digitorum longus muscle removed three days later. Intracellular microelectrode recordings were then made of miniature end-plate potentials (mepps). The mepp frequency was reduced by botulinum toxin, while mepp rise times were slowed. Mepp amplitude distributions became characteristically skew. beta-Bungarotoxin (140 nM) was applied to normal muscles in vitro and recordings were made 10-30 min later. The main effect was an increase in mepp frequency during this period. Mepp rise times were unaffected. When beta-bungarotoxin was applied in vitro to muscles treated with botulinum toxin there was also an increase in mepp frequency, although to a value less than in normal muscles. The mepp rise times were speeded up to normal values. The mepp amplitude and rise time distributions showed no obvious evidence for the addition of a second component to the distribution. The data appear to support the hypothesis that the sites for spontaneous release in botulinised muscle may be located at or near the usual release sites at the active zones.