Elemental mercury exposure among children of thermometer plant workers.

Because evidence of mercury exposure was found among workers of a mercury thermometer-manufacturing plant in March 1984, the Vermont Department of Health studied the workers' children for both exposure to mercury and evidence of mercury toxicity. The median urine mercury level of 23 workers' children was 25 micrograms/L. This was significantly higher than the level (5 micrograms/L) among 39 children randomly selected from nonworkers' households in the same community (P less than .001). Mercury-in-air levels measured in workers' homes were higher than those measured in control homes. A significant correlation was found between the urine mercury levels of the workers' children and the urine mercury levels of their working parents. No child had frank mercury toxicity. No evidence of neurologic toxicity among exposed children was discovered by a pediatric neurologist who examined these and unexposed children without knowledge of their exposure status. This is the first report demonstrating mercury exposure in children of mercury workers. Although toxic effects of mercury were not demonstrated at these levels of exposure, children of mercury workers are at risk for mercury exposure and potential mercury toxicity.

Drinking-water-induced copper intoxication in a Vermont family.

Three of four family members reported recurrent episodes of gastrointestinal illness while residing in a house in a small northwestern Vermont village. The father and two daughters repeatedly experienced episodes of emesis and abdominal pain after drinking water drawn from their kitchen faucet. One early-morning water sample taken from the family household contained a copper level of 7.8 mg/L, which is above the standard for drinking water (1.0 mg/L). Values for the second daughter's copper in hair analysis (1,200 micrograms/g) and copper in nail analysis (100 micrograms/g) were elevated (normal range 11 to 53 micrograms/g). The household was at the end of a 3/4-in (19.05-mm) copper main, and it is suspected that copper levels increased in water when the water remained stagnant in the main. All symptoms of the family resolved when they stopped drinking water in their home. This is the first report of copper-induced gastrointestinal illness attributable to a public supply of drinking water.

Investigation of a food-borne outbreak of salmonellosis among hospital employees.

An explosive outbreak of Salmonella enterocolitis developed in 27 hospital employees in an acute-care community hospital in Rhode Island in 1987. Salmonella typhimurium was isolated from the stools of 19 employees during the outbreak. In each patient the implicated organism had an identical antibiotic susceptibility pattern, biotype, plasmid profile, and restriction endonuclease digestion pattern. The outbreak was limited to health care workers and other hospital employees; there were no cases in hospitalized patients. Of the afflicted employees 96% ate in the hospital cafeteria on July 11 or 12, 1987. Food-specific attack rates, based on the dietary histories of ill employees and 50 healthy employees who ate in the cafeteria that weekend, indicated an association between the ingestion of salads and illness (p less than 0.01). One food service employee, in whom symptoms of abdominal cramping and diarrhea had developed 6 days earlier, had prepared the implicated foods. S. typhimurium with the identical characteristics of the outbreak strain was isolated from the stools of this food service employee. Environmental cultures and cultures of meat, poultry, and dairy sources for the cafeteria all showed negative results. Food service employees need to be counseled against working during any symptomatic enteric illness and require thorough instruction on hygienic food handling.

On-line pork carcass grading with the Autofom ultrasound system.

On-line pork carcass grading with the Autofom ultrasound system is described. The system consists of 16 ultrasound transducers positioned in a frame. The carcass is measured fully automatically at 3,200 positions to a depth of approximately 12 cm with a depth resolution of .19 mm. The ultrasound data form a three-dimensional ultrasound image, which is processed for noise reduction, orientation detection, and extraction of 127 features describing the carcass composition. The image features are used in a multivariate regression model, that is used for on-line predictions. On-line tests performed at line speeds up to 1,150 carcasses/h provide predictions of the meat percentage with an accuracy of 1.58 to 1.95%. Good predictions of the fat thickness and primal meat cuts have also been made.

Determination of lean meat in pig carcasses with the Autofom classification system.

A fully automatic classification equipment called Autofom for use at pig abattoirs has been developed and tested. It measures fat- and meat depth in carcasses by use of ultrasound. Measurement with Autofom is very fast (measuring up to 1250 carcasses per hour). It is non-invasive and low maintenance costs can be expected due to lack of moving parts. The repeatability and reproducibility have been estimated. An equation for calculating lean meat percentage on the basis of Autofom measurements has been calculated. The accuracy of the equation, expressed by residual mean square error and by standard error of prediction, is 1.84 and 1.95, respectively. A functionality test shows that, when installed on-line at the abattoir, 99% of the carcasses can be classified by Autofom. The equipment will be a suitable alternative to automatic on-line determination of lean meat percentage in pig carcasses.

Prediction of water-holding capacity and composition of porcine meat by comparative spectroscopy.

Four spectroscopic instruments, a fibre optical probe (FOP), a visual (VIS) and near infrared (NIR) reflectance spectrophotometer, a reflectance spectrofluorometer and a low-field (1)H nuclear magnetic resonance (LF-NMR) instrument were used to perform measurements on two muscles (longissimus dorsi and semitendinosous) from 39 pigs, 18 of which were carriers of the Halothane gene. Water-holding capacity (drip loss and filter paper wetness) and chemical composition (intramuscular fat and water) of the muscle samples were determined for spectroscopic calibration. Prediction models were established by partial least squares regression to evaluate the potential of using the spectroscopic techniques in an on-line slaughterhouse system. VIS data gave good prediction models, indicating that current industrial colour systems can be advanced into more specific meat evaluation systems by including the entire visible spectral range. The FOP and fluorescence measurements were less successful, and suffered from sampling problems since they measure only a small area. The best regression models were obtained from LF-NMR data for all reference quality measures and yielded a correlation coefficient of 0.75 with drip loss. LF-NMR proved able to distinguish between the two muscles and the results for their longitudinal relaxation times, T(21), were proportional to their average myofibrillar cross-sectional areas reported in the literature.

Warmed-over flavour in porcine meat - a combined spectroscopic, sensory and chemometric study.

The effectiveness of applying rapid spectral techniques in the prediction of meat quality in relation to pre-slaughter stress and warmed-over flavour (WOF) was investigated. The effect of pre-slaughter stress on the development of WOF is a relatively new area of interest in WOF research. The present study investigated the relationship between pre-slaughter stress and WOF characteristics (after 0 to 5 days' storage) in porcine meat as evaluated by chemical, sensory and spectroscopic methods. Sensory evaluation, visual reflectance spectroscopy (VIS) and low-field (1)H NMR (LF-NMR) proved efficient in describing the different stress groups and the storage period, whereas fluorescence spectroscopy and the TBARS test were only able to follow WOF during storage. Near Infrared Reflectance (NIR) and Raman scatter showed a very weak relationship to pre-slaughter stress and levels of WOF during storage. Good correlations (up to r=0.93) of sensory terms were achieved with VIS and fluorescence spectroscopy and LF-NMR.

The Minnesota Fatal Accident Circumstances and Epidemiology Study. Surveillance of occupational fatalities.

This report describes the Minnesota Fatal Accident Circumstances and Epidemiology Study (MN FACE), a new federally funded initiative to study fatal injuries in the workplace. Its primary objective is to reduce occupational fatalities. Fatalities due to falls, electrocutions, and asphyxiation caused by entry into confined spaces are currently investigated in Minnesota. MN FACE determines risk factors associated with fatalities then develops interventions for their mitigation or elimination. A comprehensive, statewide surveillance system, including state agencies, associations, organized labor, and industry, has been established to reduce the amount of bias in reporting.

Motor events in equine large colon.

The equine large colon is the major cellulose-fermentation locus of these species. The area of juncture of the ventral and dorsal divisions of the equine large colon was characterized, in 13 chronic unanesthetized animals and in 25 in vitro preparations, as an area of resistance to aboral flow. This is a probable pacemaker area. The reservoir function of this part of the colon is apparently facilitated by the presence of a pacemaker at this level. There was a general rise in recorded intraluminal pressure peaks during the first hour of feeding. This characteristic was not altered after resection of the extrinsic nerve supply. Electrical stimulation of the extrinsic nerve net in conscious animals at times mimicked the groups of intraluminal pressure peaks seen at the beginning of feeding.

Equine pelvic flexure impaction. A model used to evaluate motor events and compare drug response.

Pelvic flexure fistulas (2.5 cm diameter) were established in eight 160 kg Shetland X ponies. Impaction was induced at the pelvic flexure 25 times in the 8 animals through partial obstruction by a 1 litre rubber rebreathing bag fixed at the fistula site. Blood flow probes were implanted on the dorsal and ventral colic arteries (right colic artery and colic branch of ileocolic artery) in two of the ponies. Intraluminal pressure changes were measured at 8 different locations in the large colon during episodes of colic and following administration of flunixin or xylazine. Episodes of colic characterized by pawing, anxiety, anorexia, and attempts to lie down during impaction correlated with longer, louder sounds on auscultation and multiple contraction (closely grouped series lasting 3-5 minutes) of greater than 40 mm Hg as interpreted from simultaneous intraluminal pressure recordings. Flunixin and xylazine relieved clinical signs for 30-60 minutes. Xylazine resulted in cessation of intraluminal pressure changes for 30 minutes, Flunixin relieved signs but did not interfere with intraluminal pressure changes. Mean arterial blood flow through the colic arteries doubled during episodes of colic. Following administration of flunixin during colic, blood flow remained elevated; however, following administration of xylazine during colic, blood flow decreased.

A large outbreak of acupuncture-associated hepatitis B.

An epidemiologic investigation of an acupuncturist's practice in Rhode Island identified 35 patients who were infected with hepatitis B virus during 1984. Of 366 patients seen by the acupuncturist during 1984, 316 (86%) completed questionnaires and submitted serum for hepatitis B serology. Use of tests for immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) identified 17 case-patients who otherwise may have gone undetected. Thirty-four of the 35 case-patients were treated in only one of the two clinics run by the acupuncturist. Patients who received a greater number of acupuncture needles during their treatment course were more likely to have been infected; the attack rate for patients who received less than 150 needles was 9%, compared with 33% for patients who received greater than or equal to 450 needles (p less than 0.001). Attack rates were higher during a one-month period when the index case-patient was more likely to have been viremic than during any other period in 1984 (relative risk = 4.1, 95% confidence interval = 2.3-7.3). While observing the acupuncturist's technique, the investigators noted several potential mechanisms for needle contamination. This study highlights the potential for transmission of hepatitis B in situations of repeated needle use.

Plasmid, serotypic, and enterotoxin analysis of Bacillus cereus in an outbreak setting.

Bacillus cereus is a recognized agent of food-borne disease. In this report we describe an outbreak of B. cereus gastroenteritis associated with consumption of beef stew among patients and staff at a Rhode Island nursing home. The beef had been improperly stored after preparation. The predominant symptoms of the illness were cramps and diarrhea; it lasted an average of 16 h. No deaths occurred. The organism was recovered from 10 of 23 stools collected from ill patients and 1 of 21 stools collected from controls (P = 0.0044, Fisher's two-tailed exact test). All isolates had the same biotype and serotype, newly designated H.26; all elaborated the diarrheal B. cereus enterotoxin when tested in rabbits by the vascular permeability reaction; and all had identical plasmid profiles, which differed from those of B. cereus strains selected randomly from other outbreaks. Plasmid analysis may prove to be a useful new tool in investigating outbreaks of B. cereus food poisoning.

Studies of glucose production in sheep using (6-3H)glucose and (U-14C)glucose.

Simultaneous primed-continuous intravenous infusions of [6-3H]glucose and [U-14C]glucose were performed on 13 fed, 4 fasted, and 4 dexamethasone-treated sheep. In 10 of the experiments on fed sheep, glucagon or insulin was infused intraportally for 2 h after control values were obtained. The 3H-labeled glucose gave glucose production values that were only 4.4 +/- 0.5, 5.4 +/- 1.0, and 5.8 +/- 0.8% higher than 14C-labeled glucose in the normal fed, fasted, and dexamethasone-treated sheep, respectively. Glucagon or insulin infusions did not significantly alter this recycling. It is condluced that a recycling of glucose carbon through metabolic intermediates is minimal in the sheep as compared with other species and also that it is not significantly altered by fasting or by hormones that affect glucose production.

Parental cigarette smoking and the risk of acute leukemia in children.

BACKGROUND: Studies of the relation between parental smoking and childhood leukemia have produced inconsistent results. In the largest case-control studies of childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) conducted to date, the authors evaluated leukemia risk relative to parental self-report of cigarette smoking. METHODS: In telephone interviews in which a structured questionnaire was used, parents of 1842 ALL patients, 517 AML patients, and their matched controls were asked about their cigarette smoking habits before, during, and after the pregnancy with the index child. Risk of leukemia was examined by histologic type, age of the child at diagnosis, immunophenotype (for ALL), and French-American-British morphology group (for AML). RESULTS: The risk of ALL was not associated with the father's ever having smoked (odds ratio [OR] = 1.04, 95% confidence interval [CI] 0.90-1.20) or the mother's ever having smoked (OR = 1.04, 95% CI 0.91-1.19). Similarly, no significant risk of AML was observed for paternal (OR = 0.88, 95% CI 0.67-1.16) or maternal smoking (OR = 0.95, 95% CI 0.74-1.22). The relative risk of leukemia was not significantly different from the null for parental smoking in any time period during or around the index pregnancy, nor was it related to the number of cigarettes, the number of years of smoking, or the number of pack-years. A small number of sporadic, statistically significant associations were found, but overall there appeared to be no association between parental cigarette smoking and ALL or AML, or any subgroup of leukemia. CONCLUSIONS: Parental smoking while pregnant or exposure to cigarette smoke shortly after birth is unlikely to contribute substantially to the risk of childhood leukemia in North America.

Occupation and industry on death certificates of long-term chemical workers: concordance with work history records.

This study evaluated the concordance between occupation and industry listed on death certificates with actual work history information for a group (n = 5,882) of long-term (10 years or more) workers at a chemical company. Match rates were calculated as the percent of death certificate occupation and company entries that were confirmed by work history data using 3-digit 1980 U.S. Census Bureau group codes. The concordance rate for industry differed by employment status at death: employed, 94.9%; inactive, 30.8%; and retired, 91.1%. Concordance on occupation was analyzed for employed (n = 467) and retired (n = 932) subjects who had computerized work histories (randomly done prior to the study) and who had matched on the company on the death certificate. Concordance ranged from 0 to 50% for the first job, to 50 to 70% for the last job, longest job, and longest job in the last 10 years of company employment. The most consistent predictor of concordance was job duration. Misclassification was reviewed by occupational category. Results from this and other investigations lead to the inevitable conclusion that usual occupation data from death certificates are grossly inadequate for studies of occupational risks.

Evidence for school transmission of Neisseria meningitidis during a Vermont outbreak.

A meningitis outbreak due to Neisseria meningitidis, serogroup C, serotype 2b, occurred in central Vermont in February, 1984. The highest incidence was in Northfield, where 7 cases occurred (129 per 100,000 population). Of these 7 cases 2 were students at Northfield High School and 5 were younger children; all had had close contact with Northfield High School students or staff in the week before illness. A case-control study demonstrated that these cases had significantly more exposure to Northfield High School students or staff in the 2 weeks before illness (112 hours) than did controls (8 hours) (P = 0.006). This finding was confirmed by a second case-control study designed to determine risk factors for the entire outbreak. School children in Northfield and their household contacts were given meningococcal A-C vaccine and sulfisoxazole prophylaxis. No further cases of meningococcal disease occurred in Northfield after the week that these control methods were initiated. Transmission of the outbreak strain of N. meningitidis appears to have occurred in a school setting with subsequent illness in household and close contacts of carriers of the outbreak strain.

Effects of elemental mercury exposure at a thermometer plant.

This study compares 84 mercury-exposed workers at a thermometer manufacturing facility with 79 unexposed workers for evidence of chronic mercury toxicity. Personal breathing-zone air concentrations of mercury ranged from 25.6 to 270.6 micrograms/m3 for thermometer workers. Urinary mercury levels in the study population ranged from 1.3 to 344.5 micrograms/g creatinine, with eight (10%) participants exceeding 150 micrograms/g creatinine and three workers exceeding 300 micrograms/g creatinine, which indicates increased absorption of mercury among the thermometer workers. All urine mercury levels in the comparison group were compatible with normal background levels in unexposed adults (less than 10 micrograms/g creatinine). Thermometer plant workers reported more symptoms than did controls; in general, these differences were not statistically significant and could not be specifically associated with mercury exposure. Static tremor, abnormal Romberg test, dysdiadochokinesia, and difficulty with heel-to-toe gait were more prevalent among thermometer workers than control workers, which could not be associated with recent mercury exposure; there was some suggestion of an association with chronic exposure. There were no intergroup differences for the standard clinical tests of renal function except for a significantly higher mean specific gravity among the thermometer workers. A positive correlation was found, however, between urinary N-acetyl-b-D-glucosaminidase (NAG) and urinary mercury. There was no consistent evidence for intergroup differences in proximal renal tubule function, as measured by urinary beta 2-microglobulin (B2M) or retinol binding protein (RBP).

Pasteurized milk as a vehicle of infection in an outbreak of listeriosis.

Between June 30th and August 30th, 1983, 49 patients in Massachusetts acquired listeriosis. Seven cases occurred in fetuses or infants and 42 in immunosuppressed adults; 14 patients (29 per cent) died. Of 40 Listeria monocytogenes isolates available for testing, 32 were serotype 4b. Two case-control studies, one matching for neighborhood of residence and the other for underlying disease, revealed that the illness was strongly associated with drinking a specific brand of pasteurized whole or 2 per cent milk (odds ratio = 9, P less than 0.01 for the neighborhood-matched study; odds ratio = 11.5, P less than 0.001 for the illness-matched study). The association with milk was further substantiated by four additional analyses that suggested the presence of a dose-response effect, demonstrated a protective effect of skim milk, associated cases with the same product in an independent study in another state, and linked a specific phage type with the disease associated with milk. The milk associated with disease came from a group of farms on which listeriosis in dairy cows was known to have occurred at the time of the outbreak. Multiple serotypes of L. monocytogenes were isolated from raw milk obtained from these farms after the outbreak. At the plant where the milk was processed, inspections revealed no evidence of improper pasteurization. These results support the hypothesis that human listeriosis can be a foodborne disease and raise questions about the ability of pasteurization to eradicate a large inoculum of L. monocytogenes from contaminated raw milk.