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Biomedical subjects

R C Roberts

Publications and source records attributed to R C Roberts.

At least 163 records · Page 9Linked to original sources
PubMed1977

Serum lysozyme levels in inflammatory bowel disease.

Serum lysozyme levels were compared in patients with Crohn's disease (CD) and chronic ulcerative colitis (CUC) to determine if the two diseases could be differentiated by this parameter. The lysozyme concentrations were measured by three different methods: 1. the turbidimetric clearance of Micrococcus lysodeikticus utilizing egg white lysozyme as a standard; 2. the lysoplate assay of Osserman and Lawlor using a human lysozyme standard obtained from Dr. Osserman and 3. the lysoplate assay obtained as a commercial kit using human lysozyme as a standard. A series of 19 CD and 23 CUC patients were compared. Contrary to the report of Falchuk, et al, the serum lysozyme levels by any of the three methods were not statistically significantly different in the two diseases. The serum levels of those with severe, moderate, or inactive disease were also not significant for CD or CUC nor in serially followed patients did levels always correspont to changes in clinical course.

Adolescent↗
PubMed1976

Visualisation of thrombi with technetium-99m urokinase. A negative report.

Direct imaging of thrombi with isotopically labelled agents would provide a convenient atraumatic method of diagnosing deep venous thrombosis. Urokinase labelled with technectium-99m has many theoretical advantages and successful use of this agent has been reported. A method for tagging urokinase with Tc-99m has been developed which preserves the clot-lysing ability of the urokinase. The thrombus imaging previously reported has not been duplicated.

Acute Disease↗
PubMed1976

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.

Antigens, Bacterial↗
PubMed1976

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.

Antigens, Bacterial↗
PubMed1976

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.

Adult↗