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Biomedical subjects

S M Dennis

Publications and source records attributed to S M Dennis.

At least 19 recordsLinked to original sources
PubMed2005

Experimental transmission of Actinobacillus seminis infection to rams.

Nine groups of four 18- to 24-month-old rams were inoculated with Actinobacillus seminis by the following routes: intraconjunctival, intranasal, oral, intravenous, intramuscular, intraepididymal, vas deferens, intraurethral or intrapreputial. Eight similar rams were left uninoculated as controls. Systemic clinical signs were minimal and were confined primarily to the inoculation sites and the scrotal contents. Mild to severe epididymitis resulted from all the routes of inoculation except intraconjunctival and intranasal. Direct inoculation into the genital tract, especially into the cauda epididymis, was more effective. Intrapreputial and intraurethral inoculation led to ascending urethral infection, and inoculation into the vas deferens resulted primarily in descending infection of the accessory sex glands. A seminis was isolated from 11 of the 36 test rams (30.6 per cent); 26 of the 36 rams, some from each of the test groups except those inoculated intravenously, reacted serologically.

Actinobacillus Infections↗
PubMed2005

Increase in daytime symptoms is a sensitive and specific criterion for predicting corticosteroid-treated exacerbations in a clinical asthma trial.

BACKGROUND: To determine which diary card variables are the most predictive for administration of additional courses of corticosteroids using the TRUST (The Regular Use of Salbutamol Trial) data set. METHODS: Logistic regression models were used to identify the extent to which a change in diary card variable affected the odds ratio (OR) for administering a course of oral or increased inhaled corticosteroids. The complete TRUST diary card data were used with over 200,000 days of diary card observations from 983 mild to moderate asthmatic subjects. RESULTS: An increase in daytime symptoms of 1-5 U over baseline was associated with an increase in the OR for starting all types of corticosteroids from two- to 60-fold. CONCLUSIONS: These results indicate that an increase in daytime symptoms of two or more over baseline strongly predicts the administration of additional corticosteroids. The results have significant implications for both clinical practice and design of clinical trials in asthma.

Acute Disease↗
PubMed2004

The dissemination of the British Guideline on the Management of Asthma 2003.

The BTS/SIGN British Guideline on the Management of Asthma was published in February 2003 (4). If health outcomes are to be influenced successfully, dissemination of the guideline and implementation of recommendations is essential. We report the dissemination activities undertaken during the 18 weeks following the guideline launch. To facilitate implementation a range of educational materials were produced reflecting the key messages from the guideline. In addition to postal mailing of the guideline to appropriate healthcare professionals, both educational materials and the guidelines were made freely available from the BTS and SIGN websites. In total, 135,710 copies of the guideline and 90,198 copies of the Quick Reference Guide were downloaded in the first 18 weeks, representing a considerable increase over the number of copies of the 1997 guidelines disseminated by mailing alone. Large quantities of educational materials were downloaded with many used for teaching purposes. An on-line survey suggested that most respondents rated the materials as useful or very useful. Using websites to disseminate guidelines is a cost-effective method of informing health professionals of their content and is a more active process than the passive receipt of mailed copies. The availability of interactive educational materials for use in teaching appears to have been popular.

Asthma↗
PubMed2000

Regular inhaled salbutamol and asthma control: the TRUST randomised trial. Therapy Working Group of the National Asthma Task Force and the MRC General Practice Research Framework.

BACKGROUND: Previous work has suggested that the long-term regular use of inhaled beta2-agonist bronchodilators might lead to a deterioration in asthma control. The aim of TRUST (The Regular Use of Salbutamol Trial) was to study the effects of regular use of inhaled salbutamol, the most widely prescribed bronchodilator in the UK, on the control of asthma. METHODS: A randomised, double-blind, placebo-controlled trial was undertaken in 983 patients with asthma being treated at least twice a week with short-acting beta2-agonist, alone or in combination with inhaled steroids (2 mg or less) daily. Patients were aged 18 years and over and were recruited from 115 general practices in the UK. 90% (881) of the patients used inhaled corticosteroid therapy, and all patients continued to use their usual inhaled beta2-agonist for symptomatic relief. Patients were randomised to receive 400 microg salbutamol or matched placebo via a Diskhaler four times per day for 12 months. The primary outcome measure was rate of exacerbations of asthma, with criteria based on data from diary cards completed daily by each patient, treatment with additional corticosteroids, or both. FINDINGS: There were no differences in the annual rate, timing, or duration of exacerbations between the two groups. The mean morning peak expiratory flow was similar for the two groups. The mean evening peak expiratory flow (p<0.001) and the diurnal variation (p<0.001) were greater, and the use of rescue bronchodilator was less (p<0.001), in the group receiving regular salbutamol. INTERPRETATION: There was no evidence that regular use of inhaled salbutamol 400 microg four times daily for a year increased the exacerbation rate of asthma in the population studied.

Administration, Inhalation↗
PubMed1993

Congenital defects of the bovine central nervous system.

What should you do if you observe a defective calf in a herd? Our suggestion is to seek qualified help to examine and diagnose the condition. Parentage should be verified by blood typing. But, most important, you can keep cattle genetically clean by having your clients report all defects in calves to their breed association and artificial insemination centers.

Animals↗
PubMed1993

Congenital defects of the bovine musculoskeletal system and joints.

A variety of structural and functional congenital defects affecting the central nervous system of cattle have been identified. This article discusses specific defects of the central nervous system. Spastic and paralytic, metabolic, and storage diseases are reviewed.

Animals↗
PubMed1993

Congenital duplication.

Almost all types of congenital duplication described in humans have been observed in food animals, and a number are illustrated in this article. Congenital duplications, especially conjoined symmetric twins, are relatively common defects in cattle. The incidence is less in sheep and in hogs, and they appear to be rare in goats. In cattle, cranial duplication is predominant; this is in contrast to caudal duplication in sheep and hogs. These differences among species are interesting and may explain why congenital duplications appear more frequently in cattle than in other domestic animals. Based on the number of eyes and ears, classification criteria for cranial duplications are proposed. The cause of congenital duplications is not known.

Abnormalities, Severe Teratoid↗
PubMed1993

Congenital defects of sheep.

With increasing incrimination of viruses, plants, and drugs as causes of ovine congenital defects, concerted efforts are required to identify environmental teratogens. Expanding knowledge of congenital defects requires studying as many defective lambs as possible; recording and documenting; detailed diagnostic examinations; genetic analyses and chromosomal examinations, whenever possible; and field investigations. Adopting standardized classification, terminology, and diagnostic procedures should improve descriptions, diagnoses, and interdisciplinary exchange of information. That, in turn, should improve our knowledge of and diagnosis of congenital defects of sheep in the future. Finally, veterinary clinicians and diagnosticians are encouraged to take an interest in congenital defects and teratology.

Animals↗
PubMed1987

Congenital defects of the bovine central nervous system.

Congenital brain defects in cattle are usually obvious at birth, but detection may depend on the nature and extent of the defect. The cause may be genetic or environmental, or the cause may be unknown. Many central nervous system defects are inherited as a simple autosomal recessive trait and may have a significant economic impact on purebred and commercial cattle operations. A common structural defect of genetic nature is internal hydrocephalus. A functional defect of simple autosomal recessive inheritance is bovine progressive degenerative myeloencephalopathy. The most significant teratogenic agents causing central nervous system defects are prenatal viral infections such as bovine virus diarrhea and bluetongue viruses. Many other defects of the central nervous system are reviewed.

Animals↗
PubMed1987

Brachygnathia superior and degenerative joint disease: a new lethal syndrome in Angus calves.

Brachygnathia superior and generalized diarthrodial degenerative joint disease were seen in 17 related, purebred Angus calves ranging in age from 2 days to 4 months. Craniometrical studies revealed decreased maxillary and palatine bone lengths and increased cranial, skull, and facial indices. Radiological evaluation of major appendicular joints demonstrated lipping of the joint margins with osteophyte formation, sclerosis of subchondral bone, and narrowing of joint spaces. Synovial fluid evaluation indicated joint degeneration but no etiologic agent. Rheumatoid factor analysis of plasma was negative. Grossly, all major appendicular joints were defective including the atlanto-occipital articulation. Lesions ranged from loss of surface luster to erosions and deep ulcers with eburnation of the subchondral bone and secondary proliferative synovitis. Histological changes were degeneration of the articular cartilage matrix, chondrocyte necrosis, flaking and fibrillation, chondrone formation, erosions and ulcers of the articular cartilage with subchondral bone sclerosis, vascular invasion with fibrosis, and chronic, nonsuppurative, proliferative synovitis. Growth plates had defective chondrocyte proliferation and hypertrophy with aberrant ossification of calcified cartilaginous matrix. Histochemical analysis of cartilage and bone failed to incriminate which component was defective, glycosaminoglycan or collagen, but indicated different distribution or absence of one or the other. Genealogic studies revealed a genetic basis for the new defect.

Animals↗
PubMed1986

Congenital cardiac defects in calves.

In a 14-year study of calves with cardiac defects, 36 had 78 congenital cardiac defects: ectopia cordia cervicalis (n = 10 defects), common aortic trunk (n = 3 defects), dextraposed aorta (n = 8 defects), duplicated major trunks (n = 1 defect), hypoplastic aorta (n = 2 defects), interventricular septal defect (n = 11), interatrial septal defect (n = 2), left ventricular hypoplasia (n = 10), patent ductus arteriosus (n = 5), patent foramen ovale (n = 5), right ventricular hypoplasia (n = 10), cor triloculare biatriatum (n = 1), endocardial fibroelastosis with calcification (n = 3), and valvular hematomas (n = 7). All septal defects were high in location and ranged from 5 to 35 mm in diameter. One calf with a septal defect also had bilateral microphthalmia.

Animals↗
PubMed1986

Effect of lasalocid, monensin and thiopeptin on rumen protozoa.

The effects of lasalocid, monensin and thiopeptin on the total number and the generic composition of rumen protozoa were determined in vivo and in vitro. Feeding lasalocid or monensin to cattle on either high grain or high roughage diets reduced total protozoal counts. Addition of lasalocid or monensin (6 to 48 micrograms ml-1) to the in vitro rumen fermentation resulted in marked reduction in protozoal numbers. The inhibition was dose dependent. Thiopeptin had no effect on rumen protozoa either in vivo or in vitro. Among the protozoal types, holotrichs (Dasytricha, Isotricha and Charonina) were unaffected by either lasalocid or monensin. Among the entodiniomorphs, Entodinium, Diplodinium and Ophryoscolex were more sensitive than the other types. Ophryoscolex purkynei was more sensitive to monensin than to lasalocid. Protozoal inhibition by lasalocid and monensin was transient because prolonged antibiotic feeding resulted in the selection of a resistant population in the rumen of cattle.

Animals↗
PubMed1985

Pathology of acute experimental Actinobacillus seminis mastitis in ewes.

Sequential pathological changes were studied for 9 days after inoculating Actinobacillus seminis in the mammary gland of sheep. The inoculated mammary glands became enlarged (2 to 4 times normal), turgid or consolidated and contained creamy or greenish-yellow viscid contents. A seminis was isolated from all inoculated udders at necropsy. Microscopically, the reaction in the udder to A. seminis may be divided into 4 overlapping phases; acute purulent, subacute purulent, necrotising, and proliferative. It was concluded that A. seminis was pathogenic for the ovine mammary gland, the clinical and pathological findings were nonspecific, and that A. seminis could survive within ovine mammary tissue for at least 9 days after inoculation.

Actinobacillus Infections↗
PubMed1984

Histopathology of experimental brucellosis in rams following vaccination with Brucella ovis.

Lesions induced by inoculation of Brucella ovis into the epididymis were compared in rams previously vaccinated with B. ovis bacterin and unvaccinated rams. Inoculation of killed B. ovis did not produce significant lesions in either group whereas prior vaccination exacerbated epididymal lesions following inoculation of live B. ovis. Increased numbers of neutrophils, macrophages and lymphocytes were present in the interstitium and neutrophilic infiltration of the epididymal duct epithelium and intraepithelial cyst formation was more prominent. The inflammatory response surrounding extravasated spermatozoa was more severe in vaccinated rams but it was not determined if the response was directed at spermatozoa or intermixed brucellae, or both.

Animals↗
PubMed1983

Comparison of the enzyme-linked immunosorbent assay and complement fixation test for detecting Brucella ovis antibodies in sheep.

A solid-phase, indirect, enzyme-linked immunosorbent assay (ELISA) was compared with the microtitre complement fixation test for detecting Brucella ovis antibodies in 220 ram sera. The ELISA was more sensitive than the complement fixation test; it demonstrated antibodies in 11 sera from known infected or vaccinated rams that were complement fixation test negative. No false positives were recorded with the ELISA and, in 36 sera positive to both tests, the ELISA titres were consistently higher than the corresponding complement fixation test titres.

Animals↗
PubMed1983

Relation of rumen ATP concentration to bacterial and protozoal numbers.

Cultures of Streptococcus bovis and mixed populations of rumen bacteria were used to investigate the concentration of ATP and rumen bacterial numbers at various stages of growth. ATP, extracted with Tris buffer, was analyzed using the firefly luciferin-luciferase bioluminescent reaction. ATP concentrations of S. bovis and mixed cultures of rumen bacteria significantly correlated with live cell counts during the log phase of growth but not during the stationary phase. The average cellular ATP concentration of rumen bacteria was calculated to be 0.3 fg of ATP per cell. Studies done with in vivo artificial rumen apparatus revealed that the protozoal contribution to rumen fluid ATP pool size was much more substantial than was the bacterial contribution. The rumen fluid ATP concentration was greater in cattle with protozoa than in those that were defaunated. Differences in ATP concentration due to size differences of ciliate protozoa were observed. Due to the unbalanced distribution of ATP in rumen microbes, ATP appears to be an unsuitable indicator of rumen microbial biomass.

Adenosine Triphosphate↗