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Biomedical subjects

T O Jones

Publications and source records attributed to T O Jones.

At least 19 recordsLinked to original sources
PubMed1995

Haemocyte changes in the Pacific oyster, Crassostrea gigas, caused by exposure to domoic acid in the diatom Pseudonitzschia pungens f. multiseries.

The physiological effects of domoic acid on the immune system of marine invertebrates, which are known to accumulate this neurotoxin, have not been investigated previously. Changes in the number and relative phagocytic activity of circulating haemocytes in Crassostrea gigas exposed to domoic acid in the diatom Pseudonitzschia pungens f. multiseries for 48 hr, followed by clearance for 240 hr, were investigated using chemiluminescence. An initial stress response to the toxin assimilation was characterized by a marked increase in number and activity of haemocytes with 4 hr of exposure to the algae. Although the toxin level in the oyster increased during the 48 hr exposure, both number and activity of haemocytes declined from the 4 hr peak values to those significantly lower than control values after 24 hr clearance. This suppression in number and activity of circulating haemocytes following the initial toxin response was rectified only after 48 hr clearance, when domoic acid levels in the oyster tissue had declined to trace levels, allowing blood cells to regain their normal characteristics.

Analysis of Variance↗
PubMed1994

Polioencephalomalacia associated with the ingestion of ammonium sulphate by sheep and cattle.

In the latter part of 1991 an unusual neurological disease was recognised on several farms in England. This report describes the case histories and clinical, biochemical and pathological findings in six calves and two lambs aged from two to 44 weeks obtained from five of these farms. Laminar cerebrocortical necrosis and severe bilateral necrosis of the thalamus and/or striatum progressing to cavitation were recognised in their brains. These changes are similar to those of experimental sulphate toxicity. Morbidity rates of 16 to 48 per cent and mortality rates of 0 to 8 per cent were recorded. The affected animals did not respond to vitamin B1 treatment; the erythrocyte transketolase levels of in-contact cattle and of one untreated affected calf and one untreated lamb were within the normal range. All five farms had recently introduced a proprietary concentrate ration containing ammonium bicarbonate. After this ration was withdrawn no new cases of nervous clinical disease were observed. It is suggested that, in at least some cases, the morphology and topography of lesions may distinguish sulphate induced polioencephalomalacia from that of sporadic thiamine-dependent cerebrocortical necrosis.

Ammonium Sulfate↗
PubMed1990

A vertically transmitted cystic renal dysplasia of lambs.

A new form of bilateral renal dysplasia in lambs appeared in a commercial sheep flock in 1982. The nature of the problem, the field investigations and the laboratory examinations carried out over three lambing seasons are described. It was concluded that the condition was vertically transmitted and genetic in origin. During the two years that accurate records were kept approximately 30 per cent of the suspected ram's progeny died with lesions of renal dysplasia. The condition recurred during a breeding trial in progeny from one of the two commercial rams originally used on the farm. An autosomal dominant mode of inheritance is suggested. The incidence illustrates the importance of keeping breeding records, especially when several rams are maintained in a flock, and the value of examining a large number of lambs post mortem.

Age Factors↗
PubMed1987

Prevention of experimental haemorrhagic septicaemia with a live vaccine.

Pasteurella multocida serotype B:3,4 isolated from a fallow deer in England was used as a vaccine to prevent haemorrhagic septicaemia. The deer strain was less virulent for calves than typical serotype B:2 of haemorrhagic septicaemia strains. It elicited antibodies in cattle that protected mice against serotype B:2 infection. The live deer vaccine containing 2 X 10(7) viable organisms per dose was used to immunise calves. Six months after vaccination, five of six calves were protected against serotype B:2 challenge. Two calves challenged nine months after vaccination survived the same challenge. The live vaccine was more efficacious than an alum precipitated vaccine in protecting calves against B:2 challenge.

Animals↗
PubMed1987

Poultry waste associated type C botulism in cattle.

Botulism in UK cattle has been confirmed by demonstrating type C botulinum toxin in sera from affected animals. Evidence is presented indicating the source of intoxication to be poultry carcasses containing type C Clostridium botulinum and its toxin. The organism was also found in poultry litter and in alimentary tract samples from slaughtered animals. The implications of these findings are discussed.

Animal Feed↗
PubMed1986

Cow milk yield and composition before development of Escherichia coli mastitis.

High milk yield, low milk fat and low milk protein were considered as possible predisposing factors to bovine Escherichia coli mastitis. Morning and afternoon milk yields were recorded in 46 Friesian cows later developing E coli mastitis and compared with 92 uninfected controls. Animals developing E coli mastitis gave a significantly higher milk yield than controls. The overall morning: afternoon ratio was (mean +/- se) 1.66 +/- 0.41, with no difference in ratio for the two groups. Further studies on 85 animals later developing E coli mastitis, and 192 controls, in four Friesian herds did not reveal differences in milk fat content (except as related to yield), milk protein or in the interrelationship of days of lactation, milk protein or in the interrelationship of days of lactation, milk fat and milk protein in the two groups. Again there was a correlation between high milk yield and a tendency to develop E coli mastitis but this may have been an age effect in both investigations. No correlation between milk yield and mastitis severity was detected. High yielders which succumbed to E coli mastitis in three herds were producing less milk than mastitis-free controls in the fourth herd which suggests that the correlation is not with yield per se.

Animals↗
PubMed1986

A review of teat factors in bovine E coli mastitis.

Escherichia coli mastitis was first reproduced in 1903 by sticking the organism to teat orifices. E coli is very common in the environment of housed dairy cows and mastitis can easily be reproduced experimentally by the introduction of as few as 20 organisms into the teat cistern via the teat duct. It is generally accepted that this is the route of natural infection but the processes by which the organisms traverse the teat duct remain unclear. The literature is reviewed and the facts and hypotheses are considered.

Animals↗
PubMed1986

Antimicrobial drug susceptibility of Staphylococcus aureus isolated from bovine mastitis.

Isolates of Staphylococcus aureus (106) from bovine mastitis were tested for susceptibility to antimicrobial agents. beta-lactamase was produced by 69.8 per cent of isolates and 7.5 per cent were resistant to streptomycin (minimum inhibitory concentration more than 32 micrograms/ml). Resistance to other agents was rare. Intrinsic resistance or tolerance to beta-lactam antibiotics was not found.

Animals↗
PubMed1986

Characterization of clinical strains of Staphylococcus aureus associated with pneumonia.

A total of 5 Staphylococcus aureus strains from patients with postinfluenzal staphylococcal pneumonia, 7 from burn patients with staphylococcal pneumonia, and 21 from the nasopharynx of carriers were phenotypically characterized. All or most strains produced coagulase, clumping factor, DNase, thermostable DNase, protease, gelatinase, lipase, and pigment; the strains were low to moderate producers of extracellular protein A, fibrinolysin, and alpha-hemolysin. All strains were sensitive to mercury, half were sensitive to arsenate and cadmium, and 67 to 92% were resistant to penicillin. Differences between strains were not statistically significant. Cell surface hydrophobicity was determined by measuring percent adsorption to hexadecane. Hydrophobicity of postinfluenzal staphylococcal pneumonia strains was significantly lower than that of pneumonia strains from burn patients and carriers (P less than 0.005). Immunoblot experiments with sera immune to one clinical test strain allowed the separation of all strains into three groups based on probe-positive reactions with primarily four staphylococcal polypeptides (154,200, 130,000, 77,100, and 64,400 molecular weight). The difference in distribution of clinical and carrier strains was highly significant (P = 0.007).

Adolescent↗