Biomedical subjects

R B Marshall

Publications and source records attributed to R B Marshall.

At least 55 records · Page 3Linked to original sources

PubMed1986

Respiratory disease in foals and the epizootiology of equine herpesvirus type 2 infection.

The epizootiology of equine herpesvirus type 2 (EHV-2) infection was investigated in Thoroughbred foals on a stud farm which in previous years had suffered economic loss due to respiratory disease. Sixteen pairs of foals and their dams were selected for this study and all of the foals became infected with EHV-2 by two to four months of age. These animals responded serologically to the virus infection as detected by an enzyme-linked immunosorbent assay (ELISA). EHV-2 infection persisted in these foals for two to six months with constant or intermittent virus recovery. This persistent infection stimulated continuous production of antibodies against EHV-2. As soon as the antibody levels reached their peak at five to six months, the isolation rate of EHV-2 from the nasal cavity of these animals decreased, and eventually by nine months of age virus could no longer be recovered. Respiratory disease was observed in ten of the 16 foals; and two severely affected animals died at two months of age. EHV-2 was isolated from both foals at ante and/or post mortem examination. It is postulated that EHV-2, either as an initiating agent or by means of immnunosuppression, caused the respiratory disease observed in these foals.

Journal Article↗

PubMed1986

Analysis of the relationships of the ploidy and cell cycle kinetics to differentiation and the female sex steroid hormone receptors in adenocarcinoma of the endometrium.

Flow cytometry was used to evaluate proliferative activity and ploidy status in 21 endometrial adenocarcinomas. These data were compared with their histologic and nuclear grades and their estrogen and progesterone receptor contents. Proliferative activity was significantly related to histologic and nuclear grades and the progesterone receptor status but not to the estrogen receptor status. Unlike the majority of solid human malignant neoplasms, only seven tumors were aneuploid, the remainder being diploid. Ploidy was not significantly associated with either grading system, receptor status, or the proliferative index.

Adenocarcinoma↗

PubMed1985

Colonisation of the respiratory tract of lambs by strains of Mycoplasma ovipneumoniae.

The age and time of year when colonisation of the nasal cavity of lambs by Mycoplasma ovipneumoniae occurs; the persistence of the organism, and its prevalence in the lungs at slaughter were examined in 2 flocks of sheep in New Zealand. No colonisation had occurred at the time of weaning at 6-7 weeks, but M. ovipneumoniae was recovered from most lambs on at least one occasion before they were slaughtered when about 8 months old. In most cases, colonisation of the nasal cavity by M. ovipneumoniae was a transient phenomenon. At slaughter M. ovipneumoniae was recovered from the lungs of 89% of the lambs of one flock and 80% of the other flock. Bacterial restriction endonuclease DNA analysis (BRENDA) of 34 nasal isolates from one flock showed that it was possible to identify 7 "groups" each with markedly different BRENDA patterns. Lambs initially colonised by one strain, often lost that strain, and if recolonisation occurred it was with a different strain. M. ovipneumoniae was recovered at slaughter from the lungs of most lambs, both normal and pneumonic. The isolates from one flock were examined by BRENDA, and approximately 90% of them gave similar or identical patterns. The predominant strain isolated from the lungs had been recovered from the nasal cavity of many of the lambs about 3 weeks earlier. This suggests that the nasal and lung isolates do not represent independent populations. However, nasal strains may differ in their ability to colonise the lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1985

Comparison of Mycoplasma ovipneumoniae isolates using bacterial restriction endonuclease DNA analysis and SDS-PAGE.

Sixteen isolates of Mycoplasma ovipneumoniae recovered from the nasal tract or lungs of sheep from different flocks in New Zealand were examined by bacterial restriction endonuclease DNA analysis (BRENDA) using EcoR1 and by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). All isolates gave BRENDA patterns which differed entirely from one another. Following 20 serial passages (corresponding to approximately 67 generations) of an isolate, no change was detected in the BRENDA pattern. When eight isolates were examined by SDS-PAGE most bands were common but, nevertheless, each isolate was unique in the sense that they differed from one another in one or more bands. The marked heterogeneity of patterns observed when strains of M. ovipneumoniae are compared by BRENDA, together with the stability of such patterns over many generations, will enable this approach to be used to study the epidemiology of individual strains of M. ovipneumoniae within a flock.

Animals↗

PubMed1985

Pathobiologic study of pituitary tumors: report of 62 cases with a review of the recent literature.

Advances in radioimmunoassay procedures, immunocytochemistry, neuroradiologic imaging, and the surgical and medical treatment of pituitary adenomas have led to reappraisal of their classification as well as refinements in the diagnostic approaches used by pathologists. Sixty-two pituitary adenomas are described, and recent advances in this field are reviewed. Most of the patients were adults, but one of the adrenocorticotropic hormone (ACTH)-producing adenomas occurred in an 11-month-old infant. Endocrine-inactive tumors (43.5 per cent) were less common than hormone-producing tumors (56.5 per cent). Local invasion was most common in the former group, followed by ACTH-producing and other hormone-producing tumors. Ultrastructural features correlated with hormonal levels in the growth hormone(GH)-secreting tumors but not in the prolactin(LTH)- or ACTH-producing tumors. The formation of 7-nm filaments in the cytoplasm of tumor cells, corresponding to Crooke's hyaline change on light microscopy, was characteristic of ACTH-producing tumors. Ultrastructural changes in the ACTH granules suggested that the filaments may be derived from the feedback action of cortisol. Prior to surgery, a Rathke's cleft cyst and a chordoma were mistaken for endocrine-inactive pituitary adenomas. In two additional cases ectopic ACTH-producing tumors of lung clinically mimicked pituitary adenoma. Conversely, one pituitary adenoma mimicked sphenoid wing meningioma. Clinical, hormonal, and radiologic data and immunocytochemical and electron microscopic studies are needed for accurate pathologic interpretation and classification of pituitary adenomas.

Adenoma↗

PubMed1985

The significance of mitotic rate: a retrospective study of 127 thyroid carcinomas.

The association between mitotic rate and biologic behavior was studied in 127 cases of thyroid cancer. Based on the observation of 12,700 high-power fields (HPF), the mitotic rate varied from 0 to 316 (33.3 +/- 4.9) mitoses/100 HPF. Mitotic rate differed among the four types of thyroid cancers and correlated inversely with the differentiation of the tumors, being highest (156.8 +/- 32.9) in the undifferentiated tumors and lowest (17.3 +/- 2.4) in the papillary tumors. By analysis of variance (AOVA), the relations between mitotic rate and the sex or age of the patient, maximal diameter of the tumor, and vascular or capsular invasion were assessed, but significant relations were not found (r2 = 44.2 per cent). Follow-up observation, possible in 74 patients, showed mitotic rate to be significantly related to the survival period (Student's t-test; P values ranging from 0.02 to 0.05). The patients who were alive five and ten years after surgery had had lower mitotic rates than those who had died during the same follow-up period. The correlation of low mitotic rate with a high degree of differentiation and low potential for invasion might, in part, explain the better surgical cure rates for papillary thyroid carcinoma than for other types of thyroid cancers.

Adenocarcinoma↗

PubMed1985

A study of enterotoxigenic Escherichia coli, serogroup 0126, by bacterial restriction endonuclease DNA analysis (BRENDA).

Sixteen isolates of Escherichia coli were subjected to bacterial restriction endonuclease DNA analysis (BRENDA). Nine of these isolates were from an outbreak of human diarrhoea and produced stable toxin, the remaining seven were non-toxigenic strains from animal and human sources. The isolates from the outbreak produced indistinguishable DNA electrophoretic patterns in spite of their assignment to seven different H serotypes. Their BRENDA patterns were markedly different from the other isolates examined. These results support the epidemiological evidence that a single-strain outbreak had occurred, and they cast doubt on the value of H typing for this particular investigation.

Bacterial Toxins↗

PubMed1985

Subspecies differentiation of Moraxella bovis by restriction endonuclease DNA analysis (BRENDA).

A total of 94 strains of Moraxella bovis have been examined by bacterial restriction endonuclease DNA analysis (BRENDA). These strains comprised isolates from the U.S.A., the U.K., in Australia, and from a number of widely separated areas within New Zealand. The strains were classified into a total of 26 different types on the basis of their BRENDA patterns. Fourteen types were present among 34 strains from the U.S.A., eight types from 17 strains in the U.K. three types from five strains in Australia but only one type resulted from all 38 New Zealand strains. Moraxella liquifaciens, M. nonliquifaciens and an atypical Moraxella sp. isolated from cattle eyes in Australia were tested and produced BRENDA patterns clearly different from those of the Moraxella bovis strains. BRENDA, when used with the restriction endonuclease EcoR1, did not provide a means of distinguishing between avirulent, nonhaemolytic M.bovis, and the virulent haemolytic strains.

Journal Article↗

PubMed1985

Age and the ability of calves to respond to a leptospiral vaccine.

The serological responses of calves at two different ages to a commercial hardjo/pomona vaccine were examined. Microscopic agglutination test (MAT) titres of a group of ten three-month-old calves and three groups of 11,12 and 12 six-month-old calves were monitored over a period of 28 weeks. The calves vaccinated at three months of age had a poorer serological response rate to vaccination (30% responded to pomona and 40% responded to hardjo) compared with those vaccinated at six months of age (91-100% responded to pomona and 83-91% responded to hardjo). Those three-month-old calves which did respond also produced a lower level of-antibody than six-month-old calves. It was concluded that in order to achieve adequate protection using commercially available leptospiral bacterins at the recommended dose, vaccination should not be undertaken routinely with animals less than six months of age. Where circumstances arise in which earlier vaccination is necessary, repeat vaccination for continued protection at six months or older is suggested.

Journal Article↗

PubMed1985

Differentiation of reference strains of leptospires of the Pomona serogroup by cross-agglutination absorption and restriction endonuclease analysis.

The serological classification of all reference strains that have been described as representing separate serovars of Leptospira interrogans within the Pomona serogroup was investigated using cross-agglutination absorption and bacterial restriction endonuclease analysis (BRENDA). Comparative cross-agglutination absorption studies indicated that cornelli CB, monjakov Monjakov and kennewicki LT1026 were homologous with pomona Pomona, and dania K1 and tsaratsova B81/7 were homologous with mozdok 5621. BRENDA confirmed these results, except that pomona Pomona and monjakov Monjakov showed a difference in the high molecular weight region. It is proposed that four serovars be currently recognised within the Pomona serogroup: pomona, mozdok, proechimys and tropica. The relative merits of the use of cross-agglutination absorption and BRENDA with respect to identification of Pomona serogroup isolates are discussed.

Agglutination Tests↗

PubMed1985

Identification by cross-agglutination absorption and restriction endonuclease analysis of leptospires of the Pomona serogroup isolated in the United Kingdom.

Five strains of Leptospira interrogans isolated in the United Kingdom and belonging to the Pomona serogroup were subjected to cross-agglutination absorption and bacterial restriction endonuclease DNA analysis (BRENDA) for their identification. British isolates were compared with reference strains representing the known serovars in the Pomona serogroup and also with isolates of the Pomona serogroup obtained from other countries. Three strains isolated from wildlife in England produced equivocal results when the cross-agglutination absorption and BRENDA results were compared. According to the World Health Organisation definition of a serovar the three English strains represented two new serovars, whereas by BRENDA all three had DNA electrophoresis patterns indistinguishable from serovar mozdok. Serovar pomona has not as yet been isolated in Great Britain and the epidemiology of the Pomona serogroup infections that have been detected by serology suggests that a serovar such as mozdok, maintained by wildlife, may be the causal agent. Two strains isolated in Northern Ireland were identified as pomona by the cross-agglutination absorption test. Further studies are needed to investigate the homogeneity of field and reference strains that are designated as pomona using the cross-agglutination absorption test.

Agglutination Tests↗

PubMed1985

Infectious jejunitis with stricture after gastrojejunostomy.

Although bacterial overgrowth has often been reported in postgastrectomy patients, inflammatory stricture near the surgical anastomosis is rare. We describe a 36-year-old woman with infectious jejunitis and subsequent jejunal stenosis after gastrojejunostomy.

Adult↗

PubMed1984

A serological study of bovine leptospirosis in the district of Taranaki.

A cross-sectional serological survey of dairy cattle in Taranaki in 1979-80 indicated that 62% (551/891) of the animals had evidence of Leptospira interrogans serovar hardjo infection as disclosed by the microscopic agglutination test. Titres to Leptospira interrogans serovar pomona were demonstrated in only 4% (23/591) of the animals examined. The high prevalence of hardjo infection is suggestive of an endemic infection whilst the low level to pomona is indicative of sporadic infection. In a detailed examination of 10 herds, 9 revealed high (55%-91%) prevalence of serological reactions to hardjo and the herd profiles of titres, indicated that the animals had become infected at one to two years of age. A field strain of hardjo from cattle as well as the usual laboratory strain (hardjoprajitno) was incorporated in the test but there were no significant differences between the results given by the two antigens.

Journal Article↗

PubMed1984

ACTH-producing pituitary adenoma in an infant with cysts of the kidneys and lungs.

The light microscopical, electron microscopical and immunohistological features of a rare ACTH-producing chromophobe adenoma of the pituitary gland in an 11-month-old infant are presented. An unusual histological feature was the presence of numerous follicles. These follicles may develop secondary to necrosis of individual tumour cells. There is only one previous report in the literature of a pituitary adenoma occurring in infancy and that tumour also produced ACTH and showed a follicular histological pattern. It is of interest that our patient also had a combination of medullary cysts of the kidneys and congenital peripheral cysts of the lungs. The association of cysts in lungs with cysts in kidneys also has been reported only once previously. We conclude that the occurrence of cysts in kidneys and lungs and a pituitary tumour in infancy represents a bizarre coincidence although an unknown common embryonic insult to these organs cannot be ruled out.

Adenoma↗

PubMed1984

Identification of Campylobacter coli isolates from animals and humans by bacterial restriction endonuclease DNA analysis.

Ninety-nine Campylobacter coli isolates were examined by bacterial restriction endonuclease DNA analysis (BRENDA) with HindIII. Isolates from poultry from the same environment had identical patterns, patterns of isolates carried by suckling piglets were generally the same as those of isolates recovered from their dams, and one human patient yielded the same BRENDA type when sampled 6 weeks later. The 14 human isolates examined produced 11 distinct BRENDA types. Forty-three C. coli isolates from pigs were represented by 20 BRENDA types. Ten C. coli isolates from the feces of gulls yielded five different BRENDA types. Thirty-two C. coli isolates from live chickens and processed chicken yielded five different BRENDA types. Three human isolates had identical DNA patterns; two were from brothers living in the same house, and the third was from a human with no apparent relationship to the brothers. Another human isolate was identical to a poultry isolate. None of the pig strains had DNA patterns resembling those of human strains, nor were the DNA patterns like those of any strains recovered from poultry or gulls. Four C. coli isolates were subcultured onto agar 23 times over a period of 45 days, and their BRENDA patterns were preserved. BRENDA shows great promise for use in epidemiological studies of C. coli.

Animals↗

PubMed1984

Restriction endonuclease DNA analysis of Leptospira interrogans serovars icterohaemorrhagiae and hebdomadis.

Antigenic variants of Leptospira interrogans serovars copenhageni and hebdomadis were examined by bacterial restriction endonuclease DNA analysis with EcoRI, XhoI, SalI, BstEII, and HindIII as the digesting enzymes. The antigenic variants were stable cloned strains which had been cultivated in media containing homologous immune serum. One of the strains examined has been reported elsewhere (R. Yanagawa and J. Takashima, Infect. Immun. 10:1439-1442) as having an antigenic makeup which more closely resembles serovar kremastos than the serovar hebdomadis parent. The closely antigenically related but naturally occurring serovars icterhaemorrhagiae strain RGA and copenhageni strain M20 were examined in parallel. No differences could be shown between the hebdomadis parent and any of its mutants. Serovars copenhageni and icterohaemorrhagiae produced patterns which differed in the high-molecular-weight bands only. The Shibaura parent strain did not differ from copenhageni M20, but the Shibaura M1 strain differed from the other mutants and from icterohaemorrhagiae RGA in its high-molecular-weight bands.

DNA Restriction Enzymes↗

PubMed1983

Leptospirosis and the maintenance host: a laboratory mouse model.

A laboratory mouse model was used to investigate the criteria that have been suggested as differentiating between a maintenance host and an accidental host for a particular leptospiral serovar. The comparative studies were conducted with serovars ballum, pomona, balcanica and hardjo. The relative pathological response, ratio of serological to bacteriological prevalence, level of serological response, age-susceptibility to infection and demonstration of artificial intraspecies transmission were found to be inadequate criteria with which to differentiate maintenance and accidental hosts for a particular serovar. The demonstration of natural intraspecies transmission was considered to be the definitive criterion for differentiating such hosts. In the light of the results obtained from the laboratory mouse model and the results obtained from field studies, a maintenance host may be defined as an animal which is capable of acting as a natural source of leptospiral infection for its own species. A maintenance population may be defined as a population of a species of animal which acts as a continuous reservoir of a serovar in a specific ecosystem.

Age Factors↗

PubMed1982

The epidemiological interpretation of serological responses to leptospiral serovars in sheep.

Serum samples were examined for evidence of leptospiral agglutinins from 928 sheep from 45 lines and kidneys from 12 of these lines for evidence of leptospiral infection. All sheep had been submitted for slaughter at meat works in the Manawatu. Serological results were analysed using the results at a minimum serum dilution in the microscopic agglutination test (MAT) of 1:24 and at a minimum dilution of 1:48. It was shown that a minimum dilution of 1:24 resulted in many non-specific or cross-reactions. A minimum dilution of 1:48 was more accurate for detecting the serological prevalence of specific agglutinins to leptospires in ovine sera. Twenty percent of the sheep had titres of 1:48 or greater to hardjo, 3.8% to pomona, 2.6% to tarassovi, 2.3% to copenhageni and 2.7% to ballum. No titres of 1:48 or greater to australis were detected. Serovar hardjo was isolated from the kidneys of three animals in one line. Eighteen months later 291 serum samples and 95 urine samples were collected from live animals on the property from which the three hardjo infected animals originated. No titres to hardjo were detected in the sera of lambs, but a serological prevalence of 44% and 84% to this serovar was demonstrated in the hoggets and ewes respectively. No leptospires were demonstrated in any of the urine samples. These results show that sporadic infection of sheep with hardjo can occur but they also indicate that infection with this serovar is not endemic and that sheep are unlikely to act as maintenance hosts for hardjo in New Zealand.

Journal Article↗