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Biomedical subjects

T M Wilson

Publications and source records attributed to T M Wilson.

At least 127 records · Page 7Linked to original sources

The origin of multiple polypeptides of molecular weight below 110 000 encoded by tobacco mosaic virus RNA in the messenger-dependent rabbit reticulocyte lysate.

Multiple polypeptides encoded by tobacco mosaic virus (TMV) RNA in the messenger-dependent rabbit reticulocyte lysate are not attributable to contaminating 3'-coterminal RNA fragments, multiple leaky termination codons or endonuclease activity opening-up legitimate or spurious internal initiation sites. Quantitative analysis of polypeptides encoded over a range of added RNA concentrations from 0.09 microgram X ml-1 to 180 micrograms X ml-1 compared with those synthesized in response to size-fractionated RNAs from a crude virus preparation, or with RNA extracted from the alkali-stable fraction of TMV suggest that apart from four legitimate virus-coded products of apparent Mr approx. 165 000, 110 000, 30 000 and 17 500 all other polypeptides arise from the overlapping 5'-proximal cistrons either by (i) site-selective endonucleolytic cleavage, (ii) sense codon misreading, or (iii) specific regions of secondary structure on TMV RNA which impede ribosome translocation.

Animals↗

Selenium toxicity and porcine focal symmetrical poliomyelomalacia: description of a field outbreak and experimental reproduction.

An acute afebrile paretic condition was diagnosed in 18 of 225 feeder pigs between eight to ten weeks of age. Nine pigs died acutely, seven pigs were euthanatized and two appeared to recover. Macroscopic lesions in the ventral horns of the cervical and lumbar/sacral spinal cord enlargements consisted of focal, bilateral, depressed areas. Histopathologically, the lesion consisted of endothelial proliferation, glial cell reaction and microcavitation. Similar lesions were observed in some brain stem motor nuclei. High selenium levels were detected in the pig feed and in pig tissues and blood. Two of five experimental pigs fed a commercial grower ration and supplemented with 52 ppm selenium as sodium selenite developed paresis and paralysis after a 29 day feeding trial. Histopathological lesions of focal symmetrical poliomyelomalacia confined to the cervical and lumbar/sacral spinal cord enlargements, and identical to those in the field cases, were produced. Select brain stem motor nuclei were also affected.

Animal Feed↗

Efficient translation of the coat protein cistron of tobacco mosaic virus in a cell-free system from Escherichia coli.

Translation of tobacco mosaic virus (TMV) RNA in a cell-free system derived from Escherichia coli (MRE 600) reveals several discrete polypeptides in the Mr range of 10,000-50,000. The major product is a polypeptide of Mr 17,500 which comigrates with authentic TMV coat protein on sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Structural investigations by peptide-mapping techniques and differential radiolabelling confirm that the major product is TMV coat protein with an N-terminal methionine. The major polypeptide product can be assembled in vitro into virus-like ribonucleoprotein particles. The structural and evolutionary implications of this observation, and the values of TMV in elucidating eukaryotic mRNA interactions with the prokaryotic protein-synthesizing machinery, are discussed.

Cell-Free System↗

Abdominal mesothelioma in an aged guinea pig (Cavia porcellus).

An adult, male guinea pig died of Bordetella bronchiseptica pneumonia during quarantine and was necropsied, Numerous, firm, pale nodules were found attached to the omentum, the parietal peritoneum, and the serosal surface of the liver and intestinal tract. Gross, light, and electron microscopic examination revealed the tumors to be mesotheliomas. To our knowledge, mesotheliomas have not been reported in this species.

Abdominal Neoplasms↗

Porcine focal symmetrical poliomyelomalacia.

An acute afebrile paretic condition was diagnosed in 16 of 100 feeder pigs between eight to ten weeks of age. Nine pigs died acutely and seven pigs were euthanized. Macroscopic lesions in the ventral horns of the cervical, thoracic, lumbar and sacral segments of the spinal cord consisted of focal, bilateral, grey depressed areas. There was a bilateral symmetrical focal poliomyelomalacia histopathologically characterized by microcavitation, endothelial and glial cell proliferation and infiltration of eosinophils. Clinical and pathological findings resemble spontaneous and experimental lesions associated with acute nicotinamide deficiency and selenium toxicosis in swine.

Animals↗

TRH testing, T4-thyrotoxicosis and the aging thyroid gland.

Secondary thyroid function tests were compared in 41 mildly thyrotoxic and 36 euthyroid patients with an elevated free thyroxine index (FT4I). A serum TSH measurement 20 minutes after intravenous TRH (delta TSH) most reliably separates these two groups. A significant delta TSH response (greater than 0.5 microU/ml) is also helpful in excluding clinical thyrotoxicosis in patients with nodular goitre. The free T3 index was normal in one-third of mildly thyrotoxic patients and in all euthyroid patients with a falsely elevated FT4I. Blunted delta TSH responses to TRH in elderly New Zealand women were associated with nodular goitre or occult thyroid nodularity revealed only by thyroid scan. The reduced TRH responses are more likely due to partial thyroid autonomy than reduced synthetic capacity of thyrotrophs in old age.

Adolescent↗

Image splitting--a technique for measuring retinal vascular reactivity.

The observation of changes of pial vessel calibre has withstood the test of time in assessing cerebrovascular reactivity. A recent refinement has been the adoption of the image splitting television technique of Baez, which allows accurate and rapid measurements of vessel calibre to be made in situ. This method has been successfully applied to the eye, where the retinal vessels are readily visible through the pupil. Results are presented of preliminary experiments in normal persons, in whom an induced increased in intraocular pressure was associated with retinal vasodilatation.

Arterioles↗

Leiomyosarcoma of urinary bladder.

Leiomyosarcoma of the bladder remains a rare diagnosis with poor therapeutic results. The available data continue to support surgical intervention as the mainstay of therapy, although other modalities have been employed with varying success. A case report and review of the literature with current treatment alternatives are presented.

Adult↗

An epizootic of bovine tuberculosis in Barbados, West Indies.

A 57 cow dairy herd, believed to be in excellent condition and producing well, was found to contain 30 tuberculous cattle after cervical skin testing employing bovine PPD tuberculin with the single intradermal comparative test. Testing was initiated after two cows from this herd were found at meat inspection to have tuberculosis. The reliability of bovine PPD tuberculin for testing as well as significant epidemiological, laboratory and meat inspection factors are presented.

Animals↗

Choroidal and cerebral blood flow in baboons measured by the external monitoring of radioactive inert gases.

Quantitative measurements of blood flow using xenon-133 to measure cerebral blood flow and krypton-85 to measure choroidal blood flow were made in 12 anesthetized baboons (Papio anubis). Analysis of the clearance curves of krypton from the eye and studies of the diffusion of krypton in the eye show that the inert gas-clearance method measures choroidal blood flow only. The mean choroidal blood flow at normocapnia in this group of baboons is 463 +/- 44 ml./100 mg./min., and the mean cerebral blood flow is 46 +/- 5 ml./100 mg./min. (mean +/- 1 S.D.).

Animals↗

The response of the choroidal and cerebral circulations to changing arterial PCO2 and acetazolamide in the baboon.

Having established control values for choroidal and cerebral blood flow in twelve baboons, the response of both circulations to changing arterial PCO2 and intravenous acetazolamide was studied. The blood flow in both circulations varied directly with the PACO2, the magnitude of the response being very similar. There was a 3.6 percent change in both choroidal and cerebral blood flow per millimeter of mercury change in PACO2. Intravenous acetazolamide (25 mg./kg.) produced an increase in flow lasting approximately 50 minutes in both cerebral and choroidal circulations.

Acetazolamide↗

Myodegeneration and suspected selenium/vitamin E deficiency in horses.

The clinical, macroscopic, and microscopic features of 10 isolated cases of myodegeneration in foals were compared. Low values for selenium and vitamin E content were found in the hay and oats from one breeding stable. Serum selenium concentrations in mares at this stable were also low. Creatinine phosphokinase and serum glutamic oxaloacetic transaminase activities were increased in 2 young foals at this stable; in 1 of these foals, both enzymatic activities were markedly reduced after treatment with vitamin E and selenium. Nutritional myodegeneration was suggested as a diagnosis in this stable, on the basis of the histologic findings, feed analyses, serum selenium values, response to treatment, and enzymatic determinations. Nine other isolated cases of nutritional myodegeneration were tentatively diagnosed on the basis of macroscopic and microscopic findings and the young age of the animal. The gross lesions included pale areas in the myocardium and skeletal muscle masses. Histologically, lesions were characterized by fragmentation and hyaline and granular changes in swollen muscle fibers in widely distributed skeletal muscle masses.

Animals↗