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Biomedical subjects

M R Hall

Publications and source records attributed to M R Hall.

At least 19 recordsLinked to original sources
PubMed1992

Clinical evaluation of the efficacy of inoculating cattle with a vaccine containing Tritrichomonas foetus.

To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 x 10(7) killed T foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (+/- 7.5 days), compared with 5.4 weeks (+/- 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals. Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1991

Endocrinological and behavioral changes associated with the onset of incubation in the duck.

Plasma levels of prolactin were measured during the onset of incubation in ducks. A rapid rise in prolactin levels from a mean of 5.7 to 33.1 ng/ml occurred during the formation of the final 20% of the clutch; during which the females increased their nest-box occupancy from 9.9 to 22.2 hours per day. A pronounced decrease in plasma progesterone levels, but not estradiol, occurred in females in the days immediately preceding the onset of incubation and termination of egg laying. A similar decrease in plasma LH occurred. Plasma corticosterone levels also decreased during the transition from egg laying to incubation. In male ducks, who play no role in incubation, LH remained constant until well into incubation when it decreased. Changes in plasma levels of prolactin are discussed in relation to tactile stimulation from the clutch and nutritional stress.

Animals↗
PubMed1990

Host response to Pasteurella multocida turbinate atrophy toxin in swine.

A porcine strain of Pasteurella multocida (serotype D:3) produced a toxin causing turbinate atrophy (TA) in pigs. The toxin (TAT), processed on a high performance liquid chromatography size exclusion column, eluted as a single peak (molecular weight of about 160,000) containing trace amounts of endotoxin (lipopolysaccharide, LPS; protein:LPS, 85:1). The eluted fraction migrated on sodium dodecyl sulfate polyacrylamide gels as a single band. It could be prevented from dissociating into two prominent polypeptides by addition of a protease inhibitor. A single dose (2.0 to 79.0 micrograms/kg) of TAT given to pigs intravenously was lethal. Doses from 0.02 to 1.0 microgram/kg caused transient clinical signs of porcine systemic toxicosis with reduced appetite, generalized weakness, depression, lethargy, weight loss, and in some instances, death. Intradermal doses of TAT (greater than or equal to 0.1 microgram/site) produced hemorrhagic areas within four hours. Systemically, TAT causes bilateral TA, lymphopenia, liver dysfunctions, and possible renal impairment. Affinity of TAT for cells of epithelial origin was demonstrated in mice given 125I-TAT. In vitro, TAT stimulated DNA and protein syntheses of peripheral blood lymphocytes and suppressed syntheses in turbinate and kidney cell cultures without being cytolytic. Biological effects of TAT were eliminated by exposure to either heat, trypsin or anti-TAT antibody.

Animals↗
PubMed1989

Immunological responses of cross-bred and in-bred miniature pigs to swine poxvirus.

Swine poxvirus (SPV), topically and subdermally applied to skin of the inguinal region of cross-bred and in-bred miniature pigs, caused typical pox lesions to occur with a pustular stage at 4 to 5 days p.i., and healing by 10 to 14 days p.i. Following inoculation, peripheral blood lymphocytes (PBLs) of the pigs showed lower transformation responses to SPV and mitogens (Concanavalin A, phytohemagglutinin and 12-0-tetradecanoyl-phorbol 13-acetate) than PBLs from uninoculated controls. The PBLs generally responded to SPV from 7 to 9 days p.i. to 23 to 30 days p.i. with a maximum transformation response at the 12 to 13 days p.i. interval. Sera from the animals generally showed presence of SPV-neutralizing antibody as early as 7 days p.i. and a peak titer at 20 days p.i. of 1:512. No detectable SPV-antibody was observed at 50 days p.i. By 51Cr release assays, PBLs displayed the ability to lyse target cells in the presence of SPV-antibody with peak lysis from the 11th through the 21st day p.i. An antibody-histocompatibility restricted cell lysis was observed at 11 and 14 days p.i. When PBLs were depleted of adherent cells, there was a reduction in lysis of target cells indicating the adherent cells were instrumental as effector cells in the presence of SPV-antibody. Control pigs not exposed to SPV showed no PBL response to SPV-antigen. Partially histocompatible and non-histocompatible porcine kidney cells were found useful as cell models for evaluating SPV-infected pigs in their effort to immunologically respond to SPV.

Animals↗
PubMed1989

Antigenic relationship among field isolates of Tritrichomonas foetus from cattle.

Analysis of protein and antigen profiles of Tritrichomonas foetus isolates from cattle from 5 western states was accomplished by sodium dodecyl sulfate polyacrylamide-gel electrophoresis, immunoblot, immunoprecipitation, and fluorography techniques. Total protein profiles of all isolates were compared by Coomassie brilliant blue staining of T foetus protein samples prepared by 4 protein-extraction methods. Antigenic tritrichomonas proteins were identified by immunoblot assay with polyclonal bovine or rabbit anti-T foetus serum. Additionally, [14C]glucosamine-labeled T foetus was used for total and antigenic glycoprotein analyses. Detectable differences in the composition of total proteins or antigenic tritrichomonal proteins were not observed among all isolates. However, intensity differences in some antigenic protein bands were apparent. Bovine and rabbit sera from immunized animals possessed antibodies to the same antigenic tritrichomonal proteins. Each T foetus isolate contained 4 to 7 molecular weight size classes of glycoprotein, which were labeled by [14C]glucosamine; however, only 3 to 4 glycoproteins were identified as antigens by bovine or rabbit antiserum.

Animals↗
PubMed1979

Histone modifications in simian virus 40 and in nucleoprotein complexes containing supercoiled viral DNA.

Simian virus (SV40) nucleoprotein complexes containing circular supercoiled viral DNA were extracted from infected cells and purified by differential centrifugation. The protein content of these complexes was compared by electrophoresis on 15% acrylamide gels with the protein content of purified SV40 virions and with histones from virus-infected cells. The electrophoretic patterns of histones from each of the sources revealed several major differences. SV40 virions contained histones H3, H2B, H2A, and H4 but not H1. Nucleoprotein complexes and host cells contained all five major histone groups. Relative to cellular histones, virion and nucleoprotein complex histones were enriched 15 to 40% in histones H3 and H4. In addition to the major classes of histones, several subfractions of histones H1, H3, and H4 were observed in acrylamide gels of proteins from SV40 virions and viral nucleoprotein complexes. Acetate labeling experiments indicated that each subfraction of histones H3 and H4 had a different level of acetylation. The histones from SV40 virions and nucleoprotein complexes were acetylated to significantly higher levels than those of infected host cells. No apparent differences in phosphorylation of the major histone groups were observed.

Acetylation↗
PubMed1979

Chromophobe adenoma of the pituitary with Cushing's syndrome and skin pigmentation.

A 76-year-old man with pigmentation and Cushing's disease is described, who was found to have a large chromophobe adenoma of the pituitary. Despite normal skull X-rays the presence of bitemporal hemianopia led to the diagnosis which was later confirmed at post-mortem. Adrenalectomy performed in the treatment of Cushing's disease may be followed by skin pigmentation and an enlarging pituitary tumour (Nelson's syndrome), changes which are commonly attributed to the removal of the negative feed-back mechanism. The spontaneous occurrence of these changes in this patient who did not undergo adrenalectomy supports the view that a pituitary tumour pre-exists in cases of Nelson's syndrome and emphasizes the importance of directing initial treatment to the pituitary.

Adenoma, Chromophobe↗
PubMed1977

A second look at emepronium bromide in urinary incontinence.

Response to oral and intramuscular emepronium bromide was assessed cystometrically in nine patients with urinary incontinence caused by an uninhibited bladder. Oral therapy had no effect, whereas intramuscular administration increased bladder capacity and significantly delayed the onset of bladder spasm and the desire to void. Plasma-propranolol response was delayed and concentrations were reduced after an oral 40 mg dose of propranolol in 3 patients who had received oral emepronium bromide. These results indicate that although oral emepronium bromide had some anticholinergic effect--i.e., in reducing gastrointestinal motility--absorption of an oral dose was not sufficient for the bladder to be affected.

Administration, Oral↗
PubMed1977

The teaching of medical ethics at Southampton University Medical School.

For centuries medical schools in Britain and elsewhere had a fairly static curriculum based on what might be called the 'three Rs' of medicine, and consequently had to make room for new subjects as the need arose in a fashion which was sometimes makeshift. However, Southampton University has only had a medical school for six years, and therefore their course on medical ethics and legal medicine was carefully integrated into the curriculum after some preliminary experiments carried out by a subcommittee which is continually reviewing the situation. Medical ethics has now a definite place in the fourth year, preceded by an introduction to ethical problems encountered in medicine in the first year. Not only do members of the medical faculty participate in this teaching but also members of the faculties of law and the arts.

Curriculum↗
PubMed1977

Gastric histology and its relation to anaemia in the elderly.

During 1 year 725 consecutive patients admitted to a geriatric unit were investigated for anaemia. 51% of men had haemoglobin levels below 13.5 g/dl and 41% of women had levels below 12 g/dl. 657 patients had an azuresin tubeless test meal following an augmented dose of histamine acid phosphate and 450 (68%) had achlorhydria. Gastric biopsies were performed on 240 of the patients with achloryhdria and 201 satisfactory biopsies were obtained. These were graded into five categories: (1) normal; (2) surface gastritis; (3) diffuse gastritis; (4) chronic atrophic gastritis, and (5) chronic atrophic gastritis with intestinal metaplasia. The grades of mucosal change could not be correlated with the presence or absence of anaemia, the state of gastric function as measured by the Schilling test for absorption of vitamin B12, or the level of vitamin B12 in the serum.

Achlorhydria↗