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Biomedical subjects

J Kenny

Publications and source records attributed to J Kenny.

At least 73 records · Page 4Linked to original sources

Exposure of cattle immunised against redwater to tick-induced challenge in the field: challenge by a heterologous strain of Babesia divergens.

Eighteen, one-and-a-half-year-old Friesian heifers and a three-year-old Friesian bull were immunised against bovine redwater by inoculation with blood infected with a known strain of Babesia divergens which had been irradiated at 30 kilorads. Three weeks later these cattle plus 10 Friesian bullocks of the same age which served as controls were introduced to a grazing area infested with ticks able to transmit infections of a heterologous strain of B divergens. The control cattle all became infected with the heterologous strain, two severely. None of the inoculated cattle became clinically affected.

Animals↗

Exposure of cattle immunised against redwater to tick challenge in the field: challenge by a homologous strain of B divergens.

A field trial was conducted in Northern Ireland to determine whether calves could be protected against babesiosis by the prior inoculation of irradiated blood infected with Babesia divergens; The trial involved 30 yearling calves. Ten were inoculated with infected blood from a donor calf after the blood had been irradiated at 25 kilorads, and 10 with blood irradiated at 30 kilorads. Their reactions to the inoculation were observed daily for a month. They were then released, along with a control group of 10 susceptible calves, into an area heavily infested with B divergens-infected Ixodes ricinus ticks for two months. Between 24 and 41 days after exposure all the control animals contracted babesiosis and six of them reacted severely. None of the immunised animals suffered clinical babesiosis although 14 had detectable low-level infections. The relative severity of the reactions of the groups of calves was reflected in their haematology.

Animals↗

Long-term lithium treatment and the kidney. Interim report on fifty patients.

This is a report on the first part of our study of the effects of long-term lithium treatment on the kidney. Creatinine clearance, maximum urinary osmolality and 24 hour urine volume have been tested in 50 affectively ill patients who have been on long-term lithium for more than one year. These findings have been compared with norms and with values of the same tests from screening prior to lithium, available for most of our patients. No evidence was found for any reduction of glomerular filtration during lithium treatment. Low clearance values found in several patients could be accounted for by their age and their pre-lithium values. Urinary concentration defect appeared frequent but the extent of the impairment is difficult to assess because of the uncertainty about the norms applicable to this group of patients. The concentration defect appeared reversible, at least in part. Polyuria above 3 litres/24 hours was found in 10% of patients. An attempt is made to draw practical conclusions from the preliminary findings.

Adult↗

A morphometric and biochemical investigation of the vesiculation of kidney microvilli.

The vesiculation of kidney proximal tubule microvilli has been examined in tissue slices, isolated brush borders and isolated microvilli. Vesiculation could be induced in tissue slices by 2,4-dinitrophenol and anoxia. Cycloheximide and fluoride had no effect. In brush borders and microvilli, the vesiculation was found to be essentially temperature-dependent. Whilst an osmotic swelling could be produced by hypo-osmolar media, the temperature-dependent vesiculation could not be prevented in hyper-osmolar media. Of a wide variety of reagents tested, only glutaraldehyde, mercuric chloride and mersalyl were effective in arresting the vesiculation. Electron micrographs show that vesiculation involves a collapse of the internal structure of the microvillus. However, the collapse was not associated with depolymerization of the microvillus actin filaments. Rather it appeared to be due to the parting of cross-bridges between the membrane and the actin filaments. The nature of these cross-bridges is discussed: it is suggested that alpha-actinin possesses the characteristics for the cross-bridging protein and that vesiculation might be explained by the displacement of alpha-actinin by tropomyosin.

Animals↗

A new two-dimensional gel electrophoresis system for the analysis of complex protein mixtures: application to the ribosome of E. coli.

A new method for two-dimensional polyacrylamide gel electrophoresis of proteins is described. The method, illustrated here by its application for the analysis of ribosomal proteins of E. coli, has a high resolving power. The proteins S15 and S16 can be resolved either following alkylation or under reducing conditions. This was not possible with urea gel systems previously employed. The method should be advantageous in the identification of the components of dimers formed with the reagent methyl 4-mercaptobutyrimidate. An additional advantage of the new method is that both dimensions are run at an acidic pH. For ribosomal proteins it is therefore unnecessary to either polymerize the protein sample in the middle of the first dimension disc gel or to electrophorese two samples with opposite polarity.

Bacterial Proteins↗

Studies on the enzymology of purified preparations of brush border from rabbit kidney.

1. A method for the preparation of brush border from rabbit kidneys is described. Contamination by other organelles was checked by electron microscopy and by the assay of marker enzymes and was low. 2. Seven enzymes, all hydrolases, were substantially enriched in the brush-border preparation and are considered to be primarily located in this structure. They are: alkaline phosphatase, maltase, trehalase, aminopeptidase A, aminopeptidase M, gamma-glutamyl transpeptidase and a neutral peptidase assayed by its ability to hydrolyse [(125)I]iodoinsulin B chain. 3. Adenosine triphosphatases were also present in the preparation, but showed lower enrichments. 4. Alkaline phosphatase was the most active phosphatase present in the preparation. The weak hydrolysis of AMP may well have been due to this enzyme rather than a specific 5'-nucleotidase. 5. The two disaccharidases in brush border were distinguished by the relative heat-stability of trehalase compared with that of maltase. 6. The individuality of the four peptidases was established by several means. The neutral peptidase and aminopeptidase M, both of which can attack insulin B chain, differed not only in response to inhibitors and activators but also in the inhibitory effect of a guinea-pig antiserum raised to rabbit aminopeptidase M. This antiserum inhibited both the purified and the brush-border activities of aminopeptidase M. The neutral peptidase and gamma-glutamyl transpeptidase were unaffected but aminopeptidase A was weakly inhibited. The characteristic responses to Ca(2+) and serine with borate served to distinguish aminopeptidase A and gamma-glutamyl transpeptidase from other peptidases. 7. No dipeptidases, tripeptidases or carboxypeptidases were identified as brush-border enzymes. 8. Incubation of brush border with papain released almost all the aminopeptidase M activity but only about half the activities of maltase, gamma-glutamyl transpeptidase and aminopeptidase A. No release of alkaline phosphatase, trehalase or the neutral peptidase was observed.

Acyltransferases↗

Hepatic incidentaloma: a modern problem.

As clinical skills give way to increased reliance on organ imaging, a new clinical problem is identified--the hepatic "incidentaloma." This may be defined as an unexpected solid filling defect in the liver of a well patient. Thirty-six such lesions have been seen in one practice over a period of 36 months. Twenty-nine (81%) were benign: 24 (67%) nonneoplastic conditions 5 (14%) benign tumors. The remaining 7 (19%) were malignant: 5 secondary tumors and 2 primary tumors. Patients with physical signs of liver mass or enlargement were more likely to harbor malignancies. An elevated serum alkaline phosphatase (SAP) was suggestive of malignancy. Hepatic hemangioma was the most common single diagnosis (20 patients, 56%). We propose a regimen of investigation which should allow diagnosis to be reached in about one-half of these patients without admission to the hospital. The rest will need at least a short hospital admission for angiography and fine-needle aspiration biopsy.

Adult↗

Schedule-induced ethanol dependence and phenobarbital preference.

Rats exposed to a daily 3-hr session of intermittent food delivery ingested physical-dependence-produced levels of 5% ethanol solution. Although this schedule induced a chronic, voluntary, daily overindulgence, this had no effect on 21-hr home-cage phenobarbital preference. The substitution of water for 5% ethanol during the daily 3-hr binge session did not change home-cage phenobarbital preference, which remained stable and similar to that of a control group of non-binging animals. This experiment and others indicate that physical dependence on ethanol does not play a major role in the maintenance of ethanol abuse or cross-abuse of the barbiturates.

Alcohol Drinking↗