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Biomedical subjects

D Bennett

Publications and source records attributed to D Bennett.

At least 253 records · Page 14Linked to original sources
PubMed1983

Reduction in infarct size, arrhythmias and chest pain by early intravenous beta blockade in suspected acute myocardial infarction.

Four hundred seventy-seven patients suspected of having had acute myocardial infarction within less than 12 hours were randomized to receive i.v. atenolol followed by oral treatment for 10 days or to a control group. In patients with ECG changes indicative of infarction at entry, i.v. atenolol significantly reduced enzyme release by one-third and enhanced R-wave preservation. In patients without such ECG changes, treatment significantly prevented the development of infarction in a proportion of patients. There was also a significant reduction in R-on-T ectopics, repetitive ventricular arrhythmias and supraventricular arrhythmias. Treated patients had significantly greater pain relief and required fewer opiate analgesics. Significantly fewer atenolol-treated patients died by 10 days (the treatment period), had nonfatal cardiac arrests, developed heart failure, or suffered reinfarction.

Administration, Oral↗
PubMed1982

Hip luxation in small animals: an evaluation of some methods of treatment.

The results of closed manipulative reduction and De Vita pinning in the treatment of small animal hip luxations have been analysed. Closed reduction is worth attempting as an initial form of treatment even in chronic luxations, but successful relocation may require more than one manipulative reduction. Inadequate placement of De Vita pins or their early migration predisposes to reluxation. Hip luxations are prone to reluxation during the eight weeks following reduction.

Animals↗
PubMed1982

Gene mapping within the T/t complex of the mouse. I. t-Lethal genes are nonallelic.

The t haplotypes of mouse chromosome 17 are natural polymorphisms in wild populations that contain mutations that affect or control such diverse functions as tail length, embryonic lethality and maturation and function of male germ cells. The major impediment to dissecting the genetics of this complex region has been its unusual property of recombination suppression in heterozygotes with wild-type chromosomes. Recently it was shown that recombination suppression does not occur in heterozygotes containing two different t haplotypes, which suggested that t chromosomes may be mismatched with respect to wild-type but share sequences that permit crossing-over between them. Thus for the first time questions of allelism and map positions of the t-lethal mutations can be addressed. We report here the results of three experiments that analyzed the tw12 haplotype trans to either tw5, tw32 or tw18. In all cases these lethal mutations were nonallelic to tw12. These results, together with evidence for functional relatedness, suggest the t-lethals may be a gene family spread out over more than 15 centiMorgans of chromosome 17.

Alleles↗
PubMed1982

Gene mapping within the T/t complex of the mouse. II. Anomalous position of the H-2 complex in t haplotypes.

Naturally occurring t haplotypes are chromosome 17 polymorphisms that suppress genetic recombination in t/+ heterozygotes over a long distance that includes the H-2 complex. There is strong linkage disequilibrium between t haplotypes and H-2 haplotypes; over 20 independently isolated t chromosomes representing eight different complementation groups share only four H-2 haplotypes. Thus t haplotypes and their associated H-2 loci are inherited en bloc as a "supergene" complex, whose frequency is driven in wild mouse populations by their high transmission from male t heterozygotes. This phenomenon must therefore serve as an important regulator of H-2 polymorphisms. Genes within the region of recombination suppression in t haplotypes have been mapped by crossing-over that occurs readily between two different t haplotypes situated in trans, and by this means we show here that the H-2 complex occupies an anomalous position in t haplotypes, mapping proximal to the locus of tf closely flanked by t-lethal mutations.

Animals↗
PubMed1982

Genetic structure and origin of t haplotypes of mice, analyzed with H-2 cDNA probes.

We investigated the genetic organization and evolutionary origin of t chromosomes of mice by examining the restriction fragment patterns of DNA from t haplotypes and normal chromosomes with cDNA probes to H-2 class I genes. On genomic DNA blots, the restriction fragments containing H-2-related sequences were highly variable among different inbred strains of mice, whereas they were very similar among different t haplotypes even when the t haplotypes carried serologically different H-2 haplotypes. These observations suggest that all t haplotypes have a common origin and are not products of independent mutational events. We also mapped the position of several restriction fragments characteristic of t DNA by using a battery of recombinant t haplotypes, defined with respect to their t-lethal factors and H-2 haplotypes. We thus show that restriction fragments containing H-2-related sequences map to the left of the H-2 class I genes in t chromosomes, a region in which the tw32 b-lethal factor also maps. The cloning of these fragments can be expected to provide an entry for the structural analysis of t DNA.

Animals↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1981

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↗
PubMed1981

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↗