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Biomedical subjects

I Roberts

Publications and source records attributed to I Roberts.

At least 271 records · Page 15Linked to original sources
PubMed1984

The isolation of lambda phage carrying DNA from the histidine and isoleucine-valine regions of the Bacillus subtilis chromosome.

From a lambda gtWES library of the chromosome of Bacillus subtilis, phages carrying DNA from the hisA and ilv-leu regions were isolated. They were identified by their ability to form complementing plaques on hisB, ilvC or leuB mutants of Escherichia coli K12 under selective conditions and in the presence of a helper phage. The his phages complemented E. coli his A, B or D mutations and could transform seven mutations in the hisA region of the B. subtilis chromosome; each carried a single EcoR1 insert of about 8.2 kb. Phages complementing E. coli ilvC or leuB mutations and carrying the equivalent B. subtilis genes ilvC and leuC transformed a range of mutations in the B. subtilis ilv-leu region. The distribution of genetic markers carried by the phages suggests that the entire ilv-leu cluster from az1A through leuD is covered in the collection of phages obtained and is carried in three EcoR1 restriction fragments of approximately 6.7, 4.7 and 2.85 kb.

Bacillus subtilis↗
PubMed1984

Paracetamol metabolites in the neonate following maternal overdose.

A case of paracetamol overdose in a 36 week pregnant woman is described. The baby was delivered by Caesarian section 6 h after the overdose. The mother but not the baby was treated with N-acetylcysteine and neither suffered liver damage. The plasma paracetamol half-life was prolonged to 10 h in the neonate compared to 2.5 h in the mother and was unaffected by a two volume exchange transfusion. The pattern of urinary metabolites in the neonate was similar to that observed in the mother, but there was a marked delay in the time taken to reach peak plasma concentrations of metabolites. This is consistent with a very slow biotransformation of the drug and may explain the relative resistance of very young children to the hepatotoxicity of paracetamol. There was no evidence of limited or decreasing capacity in sulphate conjugation nor was sulphation the major metabolic pathway. In retrospect both the obstetrical intervention and the exchange transfusion were unnecessary.

Acetaminophen↗
PubMed1984

A simple method for the measurement of arginine in serum.

A simple method for the direct measurement of arginine in 40 microL of serum is described. The technique is rapid (22 samples within 10 minutes), inexpensive (reagent cost: pounds 0.03 per test), accurate and relatively precise. The limit of detection is 1 mmol/L: it is therefore not suitable for normal basal arginine concentrations, but can be used when arginine concentrations are known to be raised.

Arginine↗
PubMed1983

Respiratory illness and hypophosphatemia.

We retrospectively reviewed the charts of 308 admissions to a pulmonary disease ward and 100 admissions to the general medical service over one year to find the prevalence, sequelae, and etiology of hypophosphatemia. The overall prevalence of low serum phosphate levels (less than 2.4 mg/dl) occurring at least once during hospitalization in chest patients was 17 percent, but was higher in patients with respiratory infections (28 percent). Moreover, the prevalence of hypophosphatemia on admission (before institution of intravenous fluid or drug therapy) was ten times higher in patients with respiratory infections than in patients with noninfectious respiratory illness or general medical patients (21 vs 2 percent, p less than 0.001). Serum phosphate less than 2.0 mg/dl occurred in 4 percent of patients. Twenty-seven percent of the patients (including two with ventilatory failure) with abnormally low serum phosphate levels had symptoms or signs of uncertain etiology later explicable by the presence of hypophosphatemia. The most common additional laboratory finding associated with hypophosphatemia was elevation of muscle enzymes. Although mortality was no higher in hypophosphatemic patients, hospital stay was twice as long as that of patients with normal levels of serum phosphate. No correlation was found between simultaneous arterial blood gases and serum phosphate levels. Two patients given antacids had severe hypophosphatemia and worsened ventilatory function; phosphate-binding antacids should be used judiciously in patients with severe respiratory disease, since they may lead to the development or worsening of hypophosphatemia and diminished ventilatory function.

Female↗
PubMed1982

Carcinoma of the lung with marked hyperamylasemia and elevated serum calcitonin.

Ectopic production of multiple peptide hormones is a frequent concomitant of neoplasia. An elderly man with metastatic small cell carcinoma of the lung presented with back pain, a right hilar mass, and was demonstrated to have markedly elevated serum calcitonin and amylase levels. Polyacrylamide gel electrophoresis revealed a striking elevation of a "salivary type" isoamylase. We report this case as an unusual association of production of both a peptide hormone and a nonhormonal peptide in a patient with a tumor of "neural crest" origin.

Aged↗
PubMed1979

The nature of piecemeal necrosis in chronic active hepatitis.

On the basis of histological studies, it is proposed that the type of liver-cell death in piecemeal necrosis is apoptosis. The characteristic inconspicuousness of apoptosis explains why the mode of hepatocyte elimination in piecemeal necrosis has hitherto remained obscure. Cell-mediated immune attack induces apoptosis, not classical necrosis, and the occurrence of apoptosis in piecemeal necrosis links the observed morphological changes in chronic active hepatitis with the other evidence for an autoimmune pathogenesis. It is significant that apoptosis does not evoke inflammation or fibroplasia. In attempting to elucidate the cause of the fibrosis that accompanies progression to cirrhosis in chronic hepatitis, it may thus be more relevant to study the effect on fibroblasts of substances liberated during lymphocyte-hepatocyte interactions than the death of the hepatocytes.

Autoimmune Diseases↗
PubMed1977

Nonspecific test reaction for antibodies to hepatitis B surface antigen in chronic HBAg carriers.

Anti-HBs was undetectable in the plasma of 303 HBsAg-positive blood donors. The apparent reactivity of anti-HBs in the chromatographically isolated IgG fractions of these antigen-positive donors was shown to be nonneutralizable by HBsAg. The false-positive antiHBs reactions were apparently due to the isolation and concentration of IgG from the plasma which was initially nonreactive for anti-HBs.

Antibodies, Viral↗
PubMed1971

Hospital beds.

Explore the source record for details and available documents.

Beds↗
PubMedDate not supplied

Rapid method for altering bacterial ribosome-binding sequences for overexpression of proteins in Escherichia coli.

In an Escherichia coli expression system, two genes, one from an anaerobic intestinal bacterium and one from E. coli, were overexpressed following the alteration of ribosome-binding (Shine-Dalgarno) sequences. For both genes, the polymerase chain reaction (PCR) was used to modify the ribosome-binding sequence and, at the same time, provide restriction endonuclease sequences at each end of the gene. These restriction endonuclease sequences were used for inserting the DNA into the E. coli plasmid vector pGEM2, which has the T7 promoter upstream from its multiple cloning sites. Each chimeric plasmid, made by ligating the PCR product into pGEM2, was transformed into E. coli strain HMS174(DE3) which, when induced, produces T7 RNA polymerase for regulated overexpression. The gene isolated from the anaerobic intestinal bacterium, a 27-kDa polypeptide gene from Eubacterium sp. strain 12708, when expressed using this system, produced about one-third of the total cell protein as measured in Coomassie-stained protein gels and confirmed by Western blots with rabbit antibody. The E. coli enzyme, a 28.4-kDa tRNA methylation enzyme, was increased fivefold in activity of cell extracts over that of the best previous strain.

Bacterial Proteins↗