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Biomedical subjects

D Bennett

Publications and source records attributed to D Bennett.

At least 289 records · Page 16Linked to original sources

Osteochondritis dissecans and fragmentation of the coronoid process in the elbow joint of the dog.

Of 26 dogs with elbow osteochondrosis, 11 had osteochondritis dissecans of the medial humeral condyle, seven had fragmentation of the coronoid process of the ulna and eight had both these lesions. Sixteen cases had bilateral involvement. The labrador and retriever breeds were most often affected and the male sex predominated. The clinical features included a foreleg lameness in a young immature dog with pain localised to the elbow joint. The most consistent radiological feature was the presence of osteophyte development especially on the dorsal aspect of the anconeal process, caused by secondary osteoarthritis. The authors are not certain that surgical treatment of elbow osteochondrosis is justified; more extended long-term studies are necessary before surgical and conservative therapeutic regimens can be fully evaluated.

Animals↗

Arthroscopy of the canine stifle joint.

An arthroscopic examination of 59 canine stifle joints, both normal and diseased, was carried out. Endoscopically the stifle joint was divided into five main anatomical compartments - the suprapatellar pouch, femoropatellar joint, medical compartment, intercondylar notch and the lateral compartment. It was possible to identify all the intra-articular structures using a single infrapatellar approach and the technique allowed an assessment of the non-osseous structures of the joint. Pathological changes were appreciated. eg, hypertrophy of the synovial membrane, articular cartilage fibrillation and erosion, meniscal degeneration and osteophyte development. The arthroscopy and biopsy forceps allowed synovial membrane biopsies to be taken under direct vision. Arthroscopy is likely to become a useful aid to the diagnosis and assessment of joint disease in the veterinary patient but it is a technique which requires patience and practice before it can be used proficiently.

Animals↗

Primary autoimmune haemolytic anaemia in the dog.

Nineteen cases of primary autoimmune haemolytic anaemia are reported in the dog. The clinical features included pale mucous membranes, weakness, lethargy and collapse. The intravascular haemolytic type of the disease was seen in nine cases and was characterised by evidence of haemolysis (eg, marked bilirubinaemia). The other 10 cases were classed as the extravascular destructive type of autoimmune haemolytic anaemia. The presence of autoantibodies (of the IgG class) and complement (C3) on the red blood cells from affected patients was demonstrated by a commercial Coombs' (antiglobulin) test which, although it has disadvantages, is satisfactory providing it is interpreted in association with the clinical, haematological and biochemical features. Treatment of these 19 dogs was with prednisolone and was successful in most cases.

Anemia, Hemolytic, Autoimmune↗

Inhibition of complement-mediated cytotoxicity of antisera by fluid secreted by the seminal vesicle of the house mouse.

The fluid from the seminal vesicles of the house mouse inhibited complement-mediated cytotoxicity of antisera against both sperm and lymphocytes. This inhibition was not reduced by heating or by absorption with sperm. Fractionation of the seminal vesicle fluid on Sephadex G-100 columns revealed three peaks of inhibitory activity, one of which appeared in the void volume of the columns. This inhibitory action of the seminal vesicle fluid may protect sperm from immunological attack in the female reproductive tract. It could explain the observation that immunization of female house mice with sperm does not prevent pregnancy. The relationship between this activity in the seminal vesicles of house mice, which is directed against the cytotoxicity of antisera, and the inhibition of cell-mediated responses to sperm reported for human and bull semen have not been investigated.

Absorption↗

Immunological studies of mouse decidual cells. II. Studies of cells in artificially induced decidua.

Cells from artificially induced decidual tissue (deciduoma) in the mouse were examined for Thy-1 surface antigen and receptors for the Fc portion of immunoglobulin G (FcR) and compared with cells of the normal decidua from 6 to day 9 of pregnancy. It was shown that (1) Thy-1 antigen is present on the same proportion of cells in decidua and deciduoma on day 6 and day 7, (2) FcR-bearing cells can be detected in similar numbers on day 6 and day 7 but this does not increase on day 8 in deciduoma as it does in decidua, and (3) progesterone treatment after induction of decidualization allowed further increase of FcR-bearing cells in deciduoma. These results present further evidence of the similarity between deciduoma and decidua in the mouse. They indicate that these two membrane markers are present in the early decidua, regardless of the presence of an embryo, and suggest that progesterone may play a part in the increase of FcR-bearing cells in the decidua during pregnancy.

Animals↗

Observations on autoimmune orchitis in sterile mice carrying a recessive lethal mutation at the T/t complex exhibiting spontaneous allergic orchitis.

Electron microscopic observations of testes of sterile, backcross T/tw18 mice which spontaneously develop allergic orchitis have demonstrated accumulations of lymphocytes and occasional plasma cells between seminiferous tubules in affected mice. Many lymphocytes appeared to be insinuated amongst cytoplasmic processes of the peritubular adventitial cells which, in most samples, provided a barrier to direct infiltration of the germinal epithelium by lymphocytes. Although lymphocytes were rarely observed within the seminiferous epithelium, extensive degeneration of spermatogenic cells was observed within affected tubules. Sertoli cells phagocytosed degenerating germ cells at all stages of differentiation. In-vitro co-cultivation of syngeneic T/tw18 spleen and testicular cells revealed that testicular cells from sterile T/tw18 mice failed to activate suppressor T lymphocytes; consequently, the syngeneic splenocytes displayed a vigorous proliferative response to testicular autoantigens. Testicular cells from younger, fertile T/tw18 males, on the other hand, behaved like testicular cells from normal mice, triggering suppressor T cell activity and, thereby, abrogating proliferation of splenocytes. These results suggest genetic factors, introduced in the course of inbreeding and associated with chromosome 17, are responsible for the failure of spermatogenic cells from sterile T/tw18 males to maintain normal tolerance to their own antigens in vivo; allergic orchitis is an extreme manifestation of the inability of the defective germ cells to initiate normal T lymphocyte mediated suppression of an immune response.

Animals↗

Immunoglobulins in the mouse uterus before implantation.

An indirect immunoperoxidase technique was used to study the distribution of IgA, IgG, IgM and albumin in the uterus of primigravid mice. As pregnancy proceeds from Days 2 to 6, IgA-containing plasma cells concentrate around the uterine glands, IgA is found in an increasing number of glands and then in the uterine lumen. At the same time the stroma is progressively invested by IgG, but IgG plasma cells are not present in significant numbers and IgG is very rarely found in glands. IgM remains in blood vessels until Day 5 when it is present in small amounts in the stroma. Albumin tends to follow a pattern similar to that of IgG but in addition is present in the lumen and in a few cells in the luminal epithelium. The growing decidua does not contain immunoglobulin. These results suggest that, as the embryo reaches the uterine lumen, IgA, produced locally by plasma cells, is secreted into the uterine lumen via uterine glands while IgG infiltrates the stroma as a result of increased permeability of the uterine capillaries at the time of implantation.

Albumins↗

Erythrocyte deformability in the pathophysiology of the microcirculation.

The most commonly used technique for assessing the deformability of red cells, i.e. the filtration of the red cells through 5 mu pore filters, is discussed in regard to the criteria which have to be fulfilled in order to accept that an in vitro measurement truly reflects a valid physiological and pathological variable.

Animals↗

The T/t-complex in the mouse: mutations that impair differentiation.

The T/t-complex in the mouse contains multiple genetic factors, capable of independent mutation and separable by recombination, that affect specific events of differentiation during embryonic development and spermatogenesis. Morphological and serological as well as biochemical studies have suggested that t-mutations are associated directly or indirectly with abnormalities of the cell surface. Recent efforts to identify the molecular nature of theses abnormalities gives evidence for at least two different types of molecules associated with complex lethal t-haplotypes. One molecule, a non-glycosylated protein of 63,000 daltons, is a direct gene product specified in apparently the same mutant form by each of over 30 independent t-haplotypes examined that contain the mutant gene responsible for tail interaction. On the other hand, the serologically defined antigenic determinants that define specific lethal t-haplotypes have been shown to reside on different oligosaccharides. The implication of these data with respect to the arrangement and function of mutant factors within the T/t-complex will be discussed.

Animals↗

Molecular analysis of the genetic relationship of trans interacting factors at the T/t complex.

The T/t complex is an extensive genetic region proximal to the H-2 complex on mouse chromosome 17, with multiple effects on embryonic development, spermatogenesis and recombination. Recently, two-dimensional gel analysis of testicular cell proteins identified a gene within the T/t complex that codes for a major cell surface-associated protein, p63/6.9 (ref. 4). The wild-type gene, Tcp-1b, codes for a 63,000-molecular weight protein (p63/6.9b), whereas a mutant allele, Tcp-1a, which occurs in all intact t haplotypes, codes for a more acidic form of the protein (p63/6.9a). Analysis of partial t haplotypes obtained from rare recombination events showed that Tcp-1a correlated completely with the tail interaction factor tT, which is thought to be a genetic allele of T, thus raising the possibility that the locus of T codes for the p63/6.9 protein. We report here that the p63/6.9 proteins produced by seven chromosomes carrying independently derived dominant mutations at the locus of T are all indistinguishable from the wild-type form; thus, the cumulative data indicate that the Tcp-1 gene is most probably not at the locus of T.

Animals↗

Early intravenous atenolol treatment in suspected acute myocardial infarction. Preliminary report of a randomised trial.

214 patients were studied in a randomised trial to determine whether administraiton of intravenous atenolol within 12 hours of chest pain reduced eventual infarct size, as estimated by cumulative enzyme release and by ECG changes. 135 patients already had ECG evidence of infarction at entry; 72 received atenolol which significantly decreased subsequent enzyme release (atenolol and control means = 121 IU, SE +/- 10 and 177 IU, SE +/- 17; 2p < 0.005) and enhanced R-wave preservation (atenolol and control means = 46% +/- 3 and 36% +/- 3; 2p < 0.02). 79 patients had no evidence of infarction at entry; 44 did not receive atenolol and 27 of these subsequently developed infarction, whereas only 11 of 35 treated patients infarcted during their hospital stay (2p < 0.01). In hospital, fewer atenolol patients died (4 vs 9), had non-fatal cardiac arrests (2 vs 6), or required therapy for heart-failure (36 vs 47). Unlike many previous trials which had negative results, in this trial we gave the drug intravenously and promptly (median of 4 hours from onset of pain to injecton), thereby achieving early beta-blockade.

Acute Disease↗

Bullous autoimmune skin disease in the dog: (2) immunopathological assessment.

The immunological examinations of two cases of pemphigus vulgaris and four cases of bullous pemphigoid in the dog are reported. Deposits of immunoglobulin and complement were identified betweeen epithelial cells of the pemphigus cases and at the epithelial/connectivce tissue junction in the pemphigoid dogs. The bullous autoimmune diseases must be considered in the differential diagnosis of mucosal and skin ulceration in the dog.

Animals↗