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Biomedical subjects

R B Marshall

Publications and source records attributed to R B Marshall.

At least 73 records · Page 4Linked to original sources

Epidemiology of leptospirosis in dairy farm workers in the Manawatu. Part II. A case-control study of high and low risk farms.

Subsequent to a cross-sectional serological survey of Manawatu dairy farm workers, a case-control study was carried out to investigate the correlation between titres to leptospiral serovars in workers and those in cattle in their herds. A total of 52 herds was investigated, 25 of which were high risk where milkers had titres of 1:96 or greater, and 27 were case-controls where milkers had no detectable agglutinin titres at a minimum serum dilution of 1:24. The serological prevalence of titres to hardjo in cattle on high risk farms (76.5%) was significantly higher (P<0.05) than on the case-control farms (60.0%). The geometric mean titres of seropositive cattle on high risk farms were also significantly higher (P<0.01) than in the cattle from the case-control farms, especially in the younger cohorts. These findings suggest that there was active endemic hardjo infection in the two- to three-year-old cattle on the high risk farms. Titres to pomona were demonstrated in only 5.2% of the cattle from both types of farm. Workers with titres to pomona tended to be from farms on which stock, especially calves, were bought-in and pigs were kept. Conventional measures for protecting milkers from contact with infected urine appeared to be ineffective and it is concluded that prevention of leptospirosis in dairy farm workers can only be achieved by elimination of infection in the herd by vaccination of cattle.

Journal Article↗

Prevention of Leptospira interrogans serovar pomona infection in cattle.

A commercial hardjo-pomona vaccine which has previously been shown to be effective against hardjo infection was tested against pomona. Following challenge all 11 six-month-old non-vaccinated calves seroconverted and pomona was isolated from blood or urine on at least one occasion from nine of them. Pomona was isolated once only, on the third day after challenge, from the blood of one of 11 vaccinated calves.

Journal Article↗

Differentiation of subtypes within Leptospira interrogans serovars Hardjo, Balcanica and Tarassovi, by bacterial restriction-endonuclease DNA analysis (BRENDA).

Various strains of Leptospira interrogans were compared by bacterial restriction-endonuclease DNA analysis (BRENDA). Field strains of serovar hardjo isolated from domestic animals in New Zealand, Australia and Northern Ireland were indistinguishable from one another but differed strikingly from the hardjo reference strain Hardjoprajitno. Similarly, field isolates of balcanica and tarassovi differed from their serovar reference strains, probably owing to a difference in epidemiological niche. Subdivision of these serovars into distinct subtypes as defined by BRENDA is therefore useful and justified. In contrast, analysis of serovars pomona, ballum and copenhageni shows that field and reference strains were identical, or differed only by a single band. It is suggested that BRENDA will overcome many of the problems associated with serological methods of identifying serovars and allow more precise definition of epidemiological relationships between strains and their hosts.

Base Sequence↗

Multiple primary malignant tumors (MPMT): study of 68 autopsy cases (1963-1980).

Review of 8428 autopsies (1870 for known cancer) showed that 68 patients had had multiple primary malignant tumors (MPMT). Those 68 cases represented 0.8 per cent of all autopsies done, 3.6 per cent of all cancer autopsies. Diagnosis of MPMT was made only at autopsy in 24 cases (35.3 per cent). Thirty-six patients were male, 32 female. Their average age was 64 +/- 2.3 years. Cancers were "synchronous" (diagnosed within a six-month period) in 15 patients, "metachronous" (diagnosed at greater than six-month intervals) in 49, and "combined" in four. Metastatic foci were seen in 53 patients. Fifty-nine patients had two primary malignant tumors (PMTs); seven had three PMTs; one had four PMTs; and one had five PMTs, for a total of 148 tumors. Over half (53.1 per cent) of the second PMTs occurred within five years of the first PMTs. First PMTs were most common in the hematopoietic system and the cervix; second PMTs were most common in the lungs and the hematopoietic system. Second PMTs were less well differentiated than index PMTs. Forty-four deaths had not been directly tumor-related. Nineteen patients with metachronous MPMT lived more than ten years. Of 23 patients with one pulmonary PMT, 22 died within two years. Concomitant findings of pulmonary artery embolism, gallstone(s), thyroid or prostatic hyperplasia, and benign tumor were common in these patients. It is hoped that accumulation of data from this and other series of MPMT will provide insight into the clinicopathologic characteristics, the causes, and the interrelationships of these lesions that constitute primarily a disease of the elderly.

Aged↗

Malignant fibrous histiocytoma of the mediastinum and lung: a report of three cases.

One case of primary malignant fibrous histiocytoma of the lung and two cases of that tumor in the mediastinum are reported. Primary malignant fibrous histiocytoma is rare in those areas, appearing more commonly in deep fascia and skeletal muscles of the extremities and torso and in the retroperitoneum. Most of the tumors contain both fibroblast-like and histiocyte-like cells; some contain pleomorphic giant cells and inflammatory cells. They are often confused with other sarcomas, and their true biologic potential is not clearly defined. Radiation appears to be a very useful adjunct to surgical therapy and was used in the cases reported here.

Female↗

Oxyphil cell adenoma and hyperparathyroidism.

Although the oxyphil cells of the human parathyroid generally are not thought to be involved in the secretion of parathyroid hormone, there have been numerous reports in the literature describing functional oxyphil cell adenomas. We reviewed 453 consecutive parathyroid explorations in 446 patients over a 13-year period and identified 15 patients whose hyperparathyroidism had been caused by adenomas composed almost exclusively of oxyphil cells. All patients were relieved of their hypercalcemia postoperatively, and there have been no recurreness during a mean follow-up of 40 months (100% follow-up). Three patients have died, all without evidence of recurrent hyperparathyroidism at the time of death. Immunoperoxidase and ultrastructural studies confirm that oxyphil cells from these adenomas contain parathyroid hormone and suggest that they are capable of secretory activity. A review of the literature showed that functional oxyphil adenomas occur more frequently than is usually appreciated, although they are an uncommon cause of primary hyperparathyroidism.

Adenoma↗

Hypercalcemic crisis secondary to a functioning parathyroid cyst.

A case of hypercalcemic crisis secondary to a large functioning parathyroid cyst is presented. Because none of the theories about the origin of parathyroid cysts are well substantiated or accepted, these cysts should be referred to simply as parathyroid cysts, functional or nonfunctional.

Aged↗

Identification of Leptospira serovars by restriction-endonuclease analysis.

Strains of Leptospira interrogans were examined by restriction-endonuclease analysis. Serovars hardjo and balcanica gave patterns that differed from each other, and from those of other members of the Hebdomadis serogroup and members of other serogroups. The method should be useful for the identification of leptospires and might throw light on problems of their classification.

DNA Restriction Enzymes↗

Leptospirosis in free-living species in New Zealand.

A total of 1296 free-living mammals and birds of 12 species was examined for serologic and bacteriologic evidence of leptospiral infection. Endemic infection with serovar ballum was found in several introduced species of mammals. Endemic ballum infection is not recognized in the same species in Great Britain, their country of origin. Possums (Trichosurus vulpecula) were found to have a high prevalence of infection with balcanica, a serovar that has been isolated from possums in Australia and from cattle, pigs and humans in Eastern Europe. Free-living lagomorphs and deer were both serologically and bacteriologically negative. Waterfowl were bacteriologically negative, and only one serological titre was found.

Animal Population Groups↗

Malignant lymphoma of the thyroid gland with plasma cell differentiation (plasmacytoma).

An unusual case of malignant lymphoma of the thyroid is reported. The predominant appearance of the neoplasm was that of a large cell ("histiocytic") lymphoma, but a discrete portion of the tumor showed features typical of plasmacytoma. Electron microscopy revealed a wide spectrum of cell types, ranging from very immature lymphoid cells to relatively well-developed plasma cells. The findings support the concept that the neoplastic process represents an immunoblastic sarcoma composed of proliferating transformed B lymphocytes (immunoblasts) and their progeny (plasma cells) rather than two distinct lymphoid neoplasms occurring simultaneously.

Aged↗