A case for medical, environmental, and safety screening.

Agriculture is one of the most hazardous occupations in the United States, yet there has been no improvement noted over the past 30 years. While occupational health and safety improvements have been noted in other industrial sections, agriculture continues to pose many unusual health threats to the farmer. Screening programs are fraught with many problems in view of the widely dispersed nature of agriculture. Pulmonary function studies, dust levels, serological testing, hearing testing and noise level production, and cholinesterase levels are but a few of the tools that are available, and are helpful in looking for problems in this most vital industry in the United States.

Cohort studies of immunologic lung disease among Wisconsin dairy farmers.

Traditionally, hypersensitivity pneumonitis (HP) or farmer's lung disease (FLD) was thought to be the major occupational respiratory problem of farmers. In recent years, other acute conditions, particularly organic dust toxic syndrome (ODTS), have been recognized as significant features of the agricultural respiratory disease picture. The differences between HP and ODTS are discussed in this article. A cohort of workers on 90 dairy farms has been under study since 1975. Prevalence of FLD was calculated at 4.2/1,000. Extensive immunologic testing of this group was conducted. Serum antibody reactivity to farmer's lung antigens was related to chronic symptoms of bronchitis and occupational asthma, but not FLD. Serology may be thought of as a measure of exposure, but not FLD.

Occupational health services for farmers.

There are many unmet health needs in the farming community, needs that are peculiar to the agriculture industry. Health research and regulations to protect the safety of the farmer have lagged far behind those for other sectors of our economy. At a time when health needs are increasing, there is a decreasing availability of hospitals, physicians, nurses, and other health care personnel. The ability of the rural section to pay for these services is also declining. The evidence calls for a multifaceted solution, with improved cooperation and understanding on the part of the consumer as well as the provider. The regional health network is one system that may help solve some of these dilemmas.

Coronary bypass operation for early postinfarction angina.

A consecutive series of 38 patients who were hospitalized in the CCU for acute myocardial infarction and who had early postinfarction angina develop were operated upon on an emergency basis within two weeks after the initial infarction. The average time for the reapperance of angina was 1.7 days. Ten patients had reinfarction which occurred on an average of 3.2 days after the reappearance of the angina. Cardiogenic shock occurred in six patients between one to six days after the angina recurred. Three of these patients had severe mitral insufficiency that required mitral valve replacement in addition to the coronary bypass operation. Delay in evaluating these patients angiographically led to complications requiring the use of the intra-aortic balloon pump in 12 patients. The mean time for the angiographic evaluation was 6.8 days after the angina had recurred and the average time for surgical intervention was 1.2 days. The operative mortality in the patients undergoing coronary angiography and surgical treatment within 24 hours after the reappearance of angina (15 patients) was zero per cent; however, when this was delayed up to 48 hours (12 patients), the mortality increased to 8.3 per cent (one patient) and if the angiographic evaluation was delayed over 48 hours after the patient became symptomatic, the operative mortality rose substantially to 27.2 per cent (three patients). Most of the delay in obtaining angiocardiographic evaluation was caused by the attempt to use additional drug therapy or the introduction of new drugs, most of them calcium-blocking agents (nifedipine). It is our belief that physicians caring for patients who have recurrent angina after acute myocardial infarction should be aware that they represent a high risk group that should be studied angiographically promptly to determine operability in order to avoid a high rate of complications and death.

Precipitating antibodies to farmer's lung antigens in a Wisconsin farming population.

The prevalence of farmer's lung disease and antibodies to farmer's lung antigens were studied in a probability sample of over 1,400 farmers in north central Wisconsin. The prevalence rate of farmer's lung disease was 4.2 per 1,000 farmers. The most prevalent antibody type was directed against Micropolyspora faeni, with 6% of the study population precipitin-positive. Prevalence of antibodies to M. faeni was associated with dairy farming, larger farms, and larger dairy herds. An additive effect of hay acreage and size of dairy herd was observed. An independent relationship was also observed for cigarette smoking, with antibodies to M. faeni more prevalent among nonsmokers.

Skin testing in farmers' lung disease.

Intradermal skin tests with a culture filtrate antigen of Micropolyspora faeni grown on a synthetic medium were performed on patients with farmers' lung disease (FLD) and well farmers with and without antibodies to a panel of FLD antigens. Seventy-five percent of the FLD patients, 79% of the well farmers with M. faeni antibody, and 5% of well farmers without M. faeni antibody had a 2+ or greater intradermal immediate skin-test reaction. Prausnitz-Küstner (P-K) reactions were positive using serum of M. faeni immediate skin test-positive FLD patients. IgG-rich fractions from a staphylococcal protein A-Sepharose column of such serum contained the sensitizing factor whereas IgG-depleted fractions did not. M. faeni-specific IgE could not be detected in serum by a polystyrene radioimmunoassay. Positive late-onset (6-hr) skin tests occurred only in FLD patients and farmers with precipitating antibody. Biopsy specimens of the 6-hr reactions revealed a generalized dermal and perivascular polymorphonuclear infiltrate with deposits of immunoglobulin and complement about blood vessels. The skin-sensitizing factor noted in FLD patients and well farmers with antibody is not disease specific. This factor appears to be associated with the IgG-rich fraction of serum, and its role in the pathogenesis of FLD is unclear.

Angiotensin-converting enzyme in farmer's lung.

Serum levels of angiotensin-converting enzyme were measured in a group of patients with farmer's lung and a group of precipitin-positive subjects with no history of farmer's lung. The levels did not differ significantly from control subjects matched for age and smoking history. The mean serum level of angiotensin-converting enzyme in a group of acutely ill patients with farmer's lung was significantly reduced. An acute challenge of three patients with Micropolyspora faeni did not produce an increase in serum levels of angiotensin-converting enzyme. These studies suggest that an increased serum level of angiotensin-converting enzyme can be a diagnostic aid in making a differential diagnosis between sarcoidosis and farmer's lung.

Serologically detectable HLA-A, B, and C loci antigens in farmer's lung disease.

The frequency of serologically detectable (SD) HLA-A, B, and C loci antigens in subjects with farmer's lung disease (N = 100) was compared with that of age- and sex-matched normal normal farmers with no precipitating antibodies to extracts of thermophilic actinomycetes. A subset of the farming population with antibodies to the thermophilic actinomycetes and no evidence of clinical disease (N = 55) was also agae- and sex-matched to the farmer's lung disease population. No significant associations between any of the SD HLA antigens tested and farmer's lung disease were found in the study. The data demonstrated that there was no association between SD HLA antigens and farmer's lung disease in random populations.

What is the probability that coronary artery surgery prolongs life?

Two-hundred and nine male patients who had coronary artery surgery from 1972 to 1974 at the Marshfield Clinic (MC) were compared with Veterans Administration (VA) coronary patients to determine the probability of coronary surgery prolonging life. The survival data includes operative and late cardiac and noncardiac deaths. Including the MC operative mortality rates but considering late noncardiac deaths withdrawn as alive at the time of death, the MC cumulative 5-year surgical survival rate is 93%. This is identical to predicted 93% 5-year survival rate for any man of 54.5 years, the average age of MC patients living in this geographic locale in 1973. Annual attrition rates, including the noncardiac deaths, are 1.4% for any man 1.5% per year for MC patients, based on MC 5-year survival data. It is probable that coronary surgery prolongs life by sharply reducing late cardiac deaths.

Characterization of precipitin response to Micropolyspora faeni in farmer's lung disease by quantitative immunoelectrophoresis.

Sera from 12 patients with farmer's lung disease (FLD) drawn during an acute episode and displaying precipitins to Micropolyspora faeni were analyzed by crossed immunoelectrophoresis with an intermediate gel combined with a rabbit reference precipitate system. Forty-six precipitin arcs were identified in the reference system, and FLD sera reacted with 36 of these antigens. The FLD sera displayed significantly more precipitates and higher precipitin scores when compared with sera from 16 precipitin-positive subjectw who did not have FLD. However, there was overlap between the 2 groups, and neither measurement distinguished the 2 persons who became ill after challenge from one person who did not. Three disease specific antigens were identified that may have special relevance for pathogenesis of disease. Ten exposure-relevant antigens were also identified. We propose that these antigens be important components of a standardized M. faeni antigen preparation.

The limited utility of fibrinogen I 125 leg scanning.

Using venography as the reference procedure, this study examined the utility of fibrinogen I 125 scanning for the detection or demonstration of deep venous thrombosis. The results demonstrate the inability of leg scanning to detect accurately the presence or absence of thrombi in the deep venous system. Most striking was the lack of sensitivity of this procedure in areas where the propensity for embolization is greatest. Sensitivity is extremely low in the anatomic areas where leg scanning demonstrates reasonable specificity. The results are nearly identical in the extremity not operated upon. The validity of all prior studies relying heavily or exclusively on 125I leg scans to determine the presence or absence of thrombi must be critically reassessed.

Farmer's lung disease among farmers with precipitating antibodies to the thermophilic actinomycetes: a clinical and immunologic study.

Farmers were evaluated for the presence of farmer's lung disease by serologic methods and by clinical histories. From a large farming population screened serologically, 40 of 92 farmers with precipitating antibodies to the thermophilic actinomycetes consented to be evaluated for clinical evidence of farmer's lung disease. Each subject completed a standardized questionnaire which was reviewd by a trained observer. On the basis of the questionnaire and an indepth clinical history, the subjects were grouped into those farmers who had a history of farmer's lung disease (38%), those with no history (50%), or a doubtful group (12%). When these groups were compared for radiologic changes, pulmonary function abnormalities, and immune function, no differences were discernible. None of the parameters tested were useful in predicting which farmer would develop clinical farmer's lung disease. The parameters tested did not provide reliable criteria for differentiating those patients who present without acute symptoms but relate a history of recurrent pulmonary illnesses associated with moldy forage.

Antibodies of different immunoglobulin classes against antigens causing farmer's lung.

A solid phase radioimmunoassay technique was used to demonstrate antibodies of various immunoglobulin classes in sera against farmer's lung antigens. IgG, IgA, and IgM antibody activity in normal patients and in patients with farmer's lung were detected against Micropolyspora faeni. Only the IgG and IgA antibody activity was different in farmers and in control subjects. An asymptomatic subject could not be differentiated from symptomatic farmers by IgG antibody activity. No IgE antibody activity was detected. The radioimmunoassay technique can be used to show antibody activity against carbohydrate antigens and as a method of evaluation of antigens by inhibition analysis. Certain types of hypersensitivity lung disease can be discriminated by in vitro analysis of serum antibody of various immunoglobulin classes. This is apparent for IgE and possibly true for IgM.

The frequency of precipitins to trichloroacetic acid-extractable antigens from thermophilic actinomycetes in farmer's lung patients and asymptomatic farmers.

The hypothesis that the trichloroacetic acid (TCA)-extractable antigen fractions prepared from Micropolyspora faeni cells and other thermophilic actinomycetes are better diagnostic immunodiffusion reagents for the detection of farmer's lung disease than the crude extracellular antigen concentrates has been tested. The frequency of serum precipitins to the TCA-extractable antigens has been compared in symptomatic farmer's lung patients and in healthy farmers having positive precipitin tests to the crude antigen concentrates of the analogous thermophilic actinomycetes. Sixty-eight per cent of the symptomatic group were found to have precipitins to the M. faeni TCA-extractable antigens compared with only 22 per cent of the asymptomatic group. With regard to the other thermophilic actinomycetes tested, no significant differences in frequencies of precipitins to TCA-extractable antigens between the symptomatic and asymptomatic groups were found. However, the total number of patients available for testing with each of these antigens was small. Sufficient chemical characterization of the TCA-extractable antigens was carried out to show that they were chemically similar to the TCA-extractable antigens prepared by other workers.

Precipitating antibodies in a midwest dairy farming population toward the antigens associated with farmer's lung disease.

A survey of the frequency of precipitins to the antigens of the thermophilic actinomycetes and Aspergillus species was conducted on serum samples from 1,045 farmers obtained at a 3-day exposition on modern farm equipment and farming practices in central Wisconsin. Each farmer filled out a questionnaire including socioeconomic information, lung disease history, exposure history, and smoking history. Precipitins were detected by the double-diffusion method. The antigen panel included eight thermophilic actinomycetes species and a mixture of Aspergillus species. Precipitins were found in the sera of 93 famers (8.9%). The distribution of positive precipitins was: Micropolyspora faeni 63 (67.7%), Thermoactinomyces vulgaris 7 (7.5%), Thermomonospora viridis 2 (2.2%), M. faeni + T. viridis 16 (17.2%), M. faeni + T. vulgaris 1 (1.1%), Aspergillus species 4 (4.3%). Of all the parameters tested for in the questionnaire, those with positive serology differed significantly from the whole population only in that a higher proportion of the positives reported exposure to silo gas and illness after uncapping silos. Comparison of the size of the farm and the number of dairy cows in the state of Wisconsin with the population samples indicated that the sample population was skewed toward those with larger farms and larger dairy herds. This study confirms that a significant proportion of the farm population in Wisconsin does have precipitins to the microorganisms associated with farmer's lung disease. Follow-up studies to establish the relationship between the positive precipitin reactions to the presence of clinical disease are now under way.

Open pulmonary biopsy. Nineteen-year experience with 416 consecutive operations.

Four hundred and sixteen open pulmonary biopsies through limited thoracotomies are reported. Tissue sufficient for diagnosis was obtained in all cases. Case selection, operative technique, spectrum of diagnoses, complications, and comparisons with other techniques are defined. Diagnoses by category were as follows: occupational, 105 patients (25 percent); neoplastic disease, 80 patients (19 percent); specific histologic diagnosis, (ie, sarcoidosis), 70 patients (17 percent); specific infection, 23 patients (6 percent); vascular diagnosis, 16 patients (4 percent); and nonspecific pulmonary disease, 122 patients (29 percent). Pneumothorax, minor in most cases, was the most common complication. It occurred in 97 (23 percent) of the patients, but only 24 (6 percent) required the placement of a chest tube. Pleural effusion occurred in 106 patients (25 percent) and was minor. Hemothorax occurred in two (0.5 percent) and superficial wound infection in three (0.7 percent). Overall mortality was 4.5 percent (19 patients). Only two deaths (0.4 percent) were related to the procedure. Open pulmonary biopsy remains our diagnostic method of choice in diffuse lung disease of undetermined etiology.

Pulmonary mycotoxicosis.

Mycotoxicosis is a term used to define a toxic reaction due to the ingestion of toxins produced by fungi. Oral ingestion, however, may not be the sole means of exposure. We have recently observed ten patients who had inhaled massive amounts of fungi, which resulted in an apparent toxic pulmonary reaction. Immunologic studies showed no sensitivity to various fungal antigen preparations and histologic study of the lung showed a multi-focal acute process, with primary involvement of the terminal bronchioles containing large numbers of various spores. Cultures from lung biopsy material revealed at least five fungal organisms. A one to ten year followup indicates that avoidance of massive reexposure to fungal dust is the key to the prevention of recurrent pulmonary mycotoxicosis.