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Biomedical subjects

M M Wagner

Publications and source records attributed to M M Wagner.

At least 55 records · Page 3Linked to original sources

Treatments affecting the rate of asbestos-induced mesotheliomas.

256 Wistar rats received a single injection into the right pleural cavity of UICC crocidolite in order to induce mesotheliomas. They were then given right intrapleural injectons of BCG, crystalline silica, talc, carrageenan or saline (as a control). There was no significant change in the mesothelioma rate in the rats exposed to BCG, silica or talc, but there was a 3-fold increase in mesothelioma incidence in the group injected with carrageenan.

Animals↗

Immunology and asbestos.

A population exposed to asbestos while working in a dockyard has been studied longitudinally. Immunological tests using markers for subsets of lymphocytes and monocytes were employed. Evidence is presented that suggests that those with progressing pulmonary fibrosis may be pinpointed. From animal experimental work in relation to mesothelioma, it is suggested that macrophages may play a role in the control of this tumour.

Asbestos↗

Effects of chrysotile asbestos on mononuclear cells in vitro.

Chrysotile asbestos (400 micrograms/ml) was not found to be cytotoxic towards human blood lymphocytes in culture over a 72 h period, although there was indirect evidence of cytoxicity towards plastic adherent mononuclear cells (PAM). There was significant suppression of 3H-thymidine incorporation into cells cultured with phytohaemagglutinin (PHA) in the presence of fibres. It was found even when chrysotile was added 24 h after PHA. No suppression was found for chrysotile-treated PAM-depleted cultures in comparison to control cultures. Antibody-dependent cell-mediated cytotoxicty (ADCC) was inhibited by the presence of chrysotile, and appeared to be due to prevention of contact between antibody-coated target cells and effector cells.

Antibody-Dependent Cell Cytotoxicity↗

Sequential immunological studies in an asbestos-exposed population. II. Factors affecting lymphocyte function.

As part of an immunological study being carried out on a population exposed to asbestos the effect of two mitogens, phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) on lymphocyte transformation has been assessed on three separate occasions for each mitogen. Both mitogens were assayed using foetal calf (FCS) or autologous serum (AS). Those men with pulmonary fibrosis (as measured by the presence of small opacities on X-ray) had a decrease (P less than 0.05) using PHA (FCS) when compared with those men with normal chest X-rays. Allowance has had to be made for the significant decline with age for both PHA (FCS and AS) transformation. There is a significant increase in PHA (FCS) and PWM (FCS) in ex-smokers and a further increase in smokers. These trends were consistent (at a lower level of significance) from survey to survey. There was no interaction between X-ray category and smoking. The lymphocyte antibody dependent cytotoxic test was measured on four occasions; the only observable effect was a non-significant increase in relation to smoking.

Aging↗

HLA-A and B antigen frequencies in an asbestos exposed population with normal and abnormal chest radiographs.

Previous studies of HLA antigen frequencies in asbestos related pulmonary fibrosis have suggested some weak associations both with susceptibility to the disease (B12 and B27) and protection from the disease (B18 and Bw35). HLA typing was performed on a further series of 64 asbestos workers with no chest abnormality and 166 workers with various radiographic changes, 78 having pulmonary fibrosis. The results fail to give statistical confirmation of these associations although B27 was twice as frequently associated with pulmonary fibrosis and diffuse pleural thickening. Analysis of the combined data from this and four other studies failed to show any consistent associations.

Asbestosis↗

HLA-A and B antigen frequencies in Welsh coalworkers with pneumoconiosis and Caplan's syndrome.

HLA typing was performed on 267 Welsh coalworkers with pneumoconiosis (96 cases of simple pneumoconiosis, 115 cases of progressive massive fibrosis and 56 cases of Caplan's Syndrome) and 134 coalworkers with no abnormality. The presence or absence of rheumatoid factor was also determined. The results fail to confirm a previously reported increase in HLA-A1 and B18 in coalworkers with no pneumoconiosis. When correction was made for the number of antigens typed (i) HLA-Bw21 was significantly increased from 1.1% in the total group with pneumoconiosis to 8.2% in coalworkers with no abnormality (P corrected less than 0.032); (ii) HLA-Bw45 was increased in Caplan's Syndrome (10.7%) and Caplan's Syndrome patients with rheumatoid factor (16.1%) when compared to a non-occupationally exposed control group (0.8%) (P corrected = 0.019 and 0.0064 respectively). These results were not significant when comparisons were made with the coalworker group with no abnormality. The apparent higher frequency of Bw45 in Welsh coalworkers is discussed.

Caplan Syndrome↗

Sequential immunological studies on an asbestos-exposed population. I. Factors affecting peripheral blood leucocytes and T lymphocytes.

Peripheral blood leucocyte counts, and E binding rosettes were measured on 138 men on five separate occasions. Little effect was seen from age, or length of asbestos exposure. Overall the most marked effect was that obtained from smoking. Most relevant was an increase in percentage of E-rosettes read after 1 1/2 hrs, which was obtained in the group of those with radiological evidence of fibrosis who smoked. Restricted to subjects with small opacities, those who smoke have a significantly higher (P less than 0.05) percentage E 1 1/2 hr rosettes than those who do not smoke. (Percentage E rosettes read overnight remained unaltered by smoking or X-ray). This increase was found on each occasion that it was measured. Since the absolute number of T lymphocytes rosetting at 1 1/2 hr did not increase, it is suggested that there is either no stimulation of the central pool of T lymphocytes or a decrease in the absolute number of T lymphocytes which could only rosette overnight.

Adult↗

Assessment of cell-mediated immunity to malignant mesothelioma by microcytotoxicity tests.

Cell cultures were established from pleural effusions of patients with pleural mesothelioma, and peripheral mononuclear effector cells were tested for cytotoxicity against these cells by means of microcytotoxicity assay. Effector cells were obtained from normal healthy donors and from persons exposed occupationally to asbestos, including apparently healthy persons, patients with benign pleural conditions and patients with malignant mesothelioma. The overall incidence of cytotoxicity was low, and there was no evidence of increased cytotoxicity in mesothelioma patients or other asbestos-exposed donors. It is concluded that little or no tumour-directed cell-mediated immunity is detectable against malignant mesothelioma by microcytotoxicity methods.

Asbestos↗

Changes with age in the hematopoietic system in a cesarean-derived, barrier-maintained colony of Wistar rats.

In a colony of cesarean-derived barrier-maintained inbred W rats given saline injections into the right pleural cavities, histologic and cytologic changes due to age were examined in the bone marrow, lymphatic tissue, and lungs; hematologic trends were also evaluated. The thymus showed two changes with age: 1) atrophy, which was evidenced by plasma cells near the blood vessels and among the cords of epithelial cells; and 2) disruption of the normal architecture of the gland. In all available thymuses, changes showed a transition toward malignancy. As the bone marrow showed increasing cellularity with time, polymorphonuclear cells and precursors appeared to increase. In lymph nodes, lymphocytes in the paracortical area were excessive and resembled the lymphocytes of the "lymphoid bursts" found in the thymus. In the lungs, small parabronchial and paravascular collections of mononuclear cells, occurring with slightly increasing frequency with age, were consistently found; however, any lung disease associated with these cells was not evident. In the blood, absolute numbers of mononuclear and polymorphonuclear cells were altered.

Aging↗

Pathogenesis of malignant histiocytic lymphoma induced by silica in a colony of specificpathogen-free Wistar rats.

The occurrence of malignant histiocytic lymphomas (MHLT) after an intrapleural inoculation of silica and the presence of a hyperplastic or granulomatous reaction to the silica were confirmed in cesarean-derived barrier-maintained inbred W rats. A specific hyperplastic reaction in the silica granulomas preceded the appearance of MHLT. Hyperplastic changes were observed when the absolute monocyte count at weeks 25-30 was slightly higher than that seen in the controls. Silica injected intrapleurally penetrated the thymus tissue but the carbon and coal dusts and the silica, which was administered by other routes, did not involve the thymus. Also, silica was the sole dust, when introduced into the coelomic cavities that produced MHLT, which grew rapidly on entering the thymus. Rats that died with MHLT had widespread dissemination with malignant foci situated most consistently above the diaphragm.

Animals↗

The accuracy of medication data in an outpatient electronic medical record.

OBJECTIVE: To measure the accuracy of medication records stored in the electronic medical record (EMR) of an outpatient geriatric center. The authors analyzed accuracy from the perspective of a clinician using the data and the perspective of a computer-based medical decision-support system (MDSS). DESIGN: Prospective cohort study. METHODS: The EMR at the geriatric center captures medication data both directly from clinicians and indirectly using encounter forms and data-entry clerks. During a scheduled office visit for medical care, the treating clinician determined whether the medication records for the patient were an accurate representation of the medications that the patient was actually taking. Using the available sources of information (the patient, the patient's vials, any caregivers, and the medical chart), the clinician determined whether the recorded data were correct, whether any data were missing, and the type and cause for each discrepancy found. RESULTS: At the geriatric center, 83% of medication records represented correctly the compound. dose, and schedule of a current medication; 91% represented correctly the compound. 0.37 current medications were missing per patient. The principal cause of errors was the patient (36.1% of errors), who misreported a medication at a previous visit or changed (stopped, started, or dose-adjusted) a medication between visits. The second most frequent cause of errors was failure to capture changes to medications made by outside clinicians, accounting for 25.9% of errors. Transcription errors were a relatively ucommon cause (8.2% of errors). When the accuracy of records from the center was analyzed from the perspective of a MDSS, 90% were correct for compound identity and 1.38 medications were missing or uncoded per patient. The cause of the additional errors of omission was a free-text "comments" field-which it is assumed would be unreadable by current MDSS applications-that was used by clinicians in 18% of records to record the identity of the medication. CONCLUSIONS: Medication records in an outpatient EMR may have significant levels of data error. Based on an analysis of correctable causes of error, the authors conclude that the most effective extension to the EMR studied would be to expand its scope to include all clinicians who can potentially change medications. Even with EMR extensions, however, ineradicable error due to patients and data entry will remain. Several implications of ineradicable error for MDSSs are discussed. The provision of a free-text "comments" field increased the accuracy of medication lists for clinician users at the expense of accuracy for a MDSS.

Aged↗