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Biomedical subjects

M Leach

Publications and source records attributed to M Leach.

At least 55 records · Page 3Linked to original sources
PubMed1988

Ethylene glycol toxicosis in a pygmy goat.

Ingestion of ethylene glycol was responsible for severe azotemia, acidosis, and abnormal anionic gap value in a pygmy goat. Clinical signs consisted of ataxia, polydipsia, decreased rumen motility, and constipation. Nervous signs included depression, absence of menace response, vertical nystagmus, and terminal convulsions. Four days after onset of clinical signs, antidotal treatment was ineffective. Lesions and oxalate crystals in the kidney were typical of ethylene glycol or plant oxalate toxicosis in other species. Toxicologic analysis revealed ethylene glycol in the rumen content and glycolic acid in urine and ocular fluid.

Animals↗
PubMed1988

A study of childhood scalds.

A retrospective review of admissions to the Wessex Regional Burn Centre was made to determine the incidence and causes of childhood scalds during the periods 1960-65 and 1979-84. No reduction in numbers injured or significant change in causes were observed. Children aged 1-2 years old are still the most prone to scalding injury.

Accidents, Home↗
PubMed1983

Gastroesophageal reflux--the acid test: scintigraphy or the pH probe?

The best established technique for diagnosing gastroesophageal reflux in children is the 24 hr esophageal pH probe test. No simultaneous comparison of this technique with radionuclide scans has been reported. Therefore, simultaneous 1 hr pH monitoring and gastroesophageal scintigraphy were performed in 49 infants and children with suspected gastroesophageal reflux. Forty-seven of these patients also were later monitored by the 24 hr pH probe test. Upper gastrointestinal series were performed on all patients. All patients with a positive 1 hr pH monitoring also had positive simultaneous scintigraphy. All patients with positive scintigraphy and pH probe monitoring also had a positive upper gastrointestinal series for reflux. The sensitivity of gastroesophageal scintigraphy, when compared to the 24 hr probe as a standard, was 79%; its specificity was 93%. The sensitivity of the upper gastrointestinal series was 86%, when compared to the 24 hr pH probe test. However, it specificity was only 21%.

Child↗
PubMed1982

A comparison of stapled and sutured anastomoses in colonic operations.

Stapled colonic anastomoses can be performed both above and below the peritoneal reflection with complication rates that are comparable with those achieved when these anastomoses are sutured by hand. The new circular stapling instrument may facilitate the performance of a lower colorectal anastomosis than can be done by hand. Operative time, return of intestinal activity and postoperative hospital stay are not significantly affected by the anastomotic technique used.

Adenocarcinoma↗
PubMed1979

Functional interactions beween the DNA ligase of Escherichia coli and components of the DNA metabolic apparatus of T4 bacteriophage.

T4 phage completely defective in both gene 30 (DNA ligase) and the rII gene (function unknown) require at least normal levels of host-derived DNA ligase (E. coli lig gene) for growth. Viable E. coli mutant strains that harbor less than 5% of the wild-type level of bacterial ligase do not support growth of T4 doubly defective in genes 30 and rII (T4 30- rII- mutants). We describe here two classes of secondary phage mutations that permit the growth of T4 30- rII- phage on ligase-defective hosts. One class mapped in T4 gene su30 (Krylov 1972) and improved T4 30- rII- phage growth on all E. coli strains, but to varying degrees that depended on levels of residual host ligase. Another class mapped in T4 gene 32 (helix-destabilizing protein) and improved growth specifically on a host carrying the lig2 mutation, but not on a host carrying another lig- lesion (lig4). Two conclusions are drawn from the work: (1) the role of DNA ligase in essential DNA metabolic processes in T4-infected E. coli is catalytic rather than stoichiometric, and (2) the E. coli DNA ligase is capable of specific functional interactions with components of the T4 DNA replication and/or repair apparatus.

Coliphages↗
PubMed1979

Antibiotic X-5108. IX. Chemical conversion of mocimycin to aurodox and derivatives of aurodox, goldinamine and mocimycin.

Mocimycin was converted to the acylesters by selective acylation of the hydroxyl group of the 4-hydroxy-1-methyl-2(1H)pyridinone moiety. Subsequent N-methylation at the nuclear nitrogen and removal of the protective group from the resulting reaction products afforded aurodox. Mono-O-acetylmocimycin and several analogous aurodox esters thus prepared possess antibacterial activity in vitro and growth-promotion properties in poultry. Esters of aurodox involving the hydroxyl group of the 4-hydroxy-1-methyl-2(1H)pyridinone moiety are activated. Accordingly, acetic acid treatment of the aurodox esters generates O-acylgoldinamines which undergo transacylation furnishing N-acylgoldinamines. Alternatively, N-acylgoldinamines can be prepared by selective mono--o-arylsulfonylation of aurodox, liberating o-arylsulfonylgoldinamine by treatment with acetic acid followed by N-acylation and removal of the protective arylsulfonyl group. A third approach to N-acylgoldinamines consists in direct N-acylation of goldinamine itself which is prepared by acetic acid treatment of aurodox. None of these derivatives prepared, however, exhibited significant antimicrobial or growth-promoting properties, suggesting that goldinonic acid moiety, or a closely related derivative thereof, is required for biological activity.

Acylation↗
PubMed1978

Antimetabolites produced by microorganisms XVI. Synthesis of N5-hydroxy-2-methylarginine and N5-hydroxy-2-methylornithine.

N5-Hydroxy-2-methylornithine and N5-hydroxy-2-methylarginine were synthesized. 2-Amino-5-hydroxy-2-methylpentanoic acid was prepared from 5-hydroxy-2-pentanone and converted to N-(tetrahydro-3-methyl-2-oxo-2H-pyran-3-yl) acetamide which was treated with hydrogen bromide affording 2-(acetylamino)-5-bromo-2-methylpentanoic acid. This acid was esterified with methanol and used to alkylate anti-benzaldoxime yielding methyl 2-(acetylamino)-2-methyl-5-[(phenylmethylene)amino]-pentanoate N5-oxide which, upon hydrolysis, yielded N5-hydroxy-2-methylornithine, and, upon aminolysis and short acid-treatment, gave N2-acetyl-N5-hydroxy-2-methylornithinamide. Carbamimidoylation and hydrolysis of the latter compound furnished N5-hydroxy-2-methylarginine.

Antimetabolites↗
PubMed1977

In vivo functional interaction between DNA polymerase and dCMP-hydroxymethylase of bacteriophage T4.

Some mutations in the structural gene for T4 DNA polymerase (gene 43) behave as suppressors of a deficiency in T4 dCMP-hydroxymethylase (gene 42). The suppression appears to involve a functional interaction between the two enzymes at the level of DNA replication. The hydroxymethylase deficiency caused DNA structural abnormalities in replication, and DNA polymerase lesions appeared to partially reverse these abnormalities. The results do not necessarily imply protein-protein interactions between the two enzymes, although both enzymes appear to play roles in controlling the fidelity of phage DNA replication.

Coliphages↗
PubMed1976

Antimetabolites produced by microorganisms. XV Synthesis of 2-methyl-L-arginine, 2-methyl-L-ornithine and their enantiomers.

5-(3-Azidopropyl)-5-methyl-2, 4-imidazolidinedione was prepared either from 5-(3-chloropropyl)-5-methyl-2,4-imidazolidinedione or 5-methyl-5-(3-[(4-methylphenyl)sulfonyloxy]-propyl)-5-methyl-2, 4-imidazolidinedione and hydrogenolyzed to the corresponding amine which, after carbamimidoylation, afforded 2-methyl-DL-arginine upon acid hydrolysis. Racemic 2-methylarginine was converted enzymically to a mixture of 2-methyl-D-arginine and 2-methyl-L-ornithine. 2-Methyl-L-arginine was reconstructed from 2-methyl-L-ornithine via its Cu(II) chelate with O-methyl-isourea and 2-methyl-D-ornithine was obtained by alkaline hydrolysis of 2-methyl-D-arginine.

Arginine↗