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Biomedical subjects

I Smith

Publications and source records attributed to I Smith.

At least 397 records · Page 22Linked to original sources
PubMed1976

Thiostrepton-resistant mutants of Bacillus subtilis: localization of resistance to the 50S subunit.

A number of thiostrepton-resistant mutants of Bacillus subtilis were obtained. The thi mutations map proximally to strA. Effects of thiostrepton on polyphenylalanine synthesis with ribosomes of S-100 fractions from parent and mutant strains indicated that resistance was localized to the ribosomes. Furthermore, effects of thiostrepton on binding of [3H]GTP to ribosomes and 50S subunits from thiostrepton-sensitive and -resistant strains localized the site of resistance to the 50S subunit. In addition, revertants from thiostrepton-resistance to thiostrepton-sensitivity were obtained. Ribosomes and 50S subunits from these thiostrepton-sensitive revertants were sensitive to thiostrepton similar to parental sensitive B. subtilis.

Anti-Bacterial Agents↗
PubMed1976

Ameloblastic dentinosarcoma- a case report.

A rare case of ameloblastic dentinosarcoma is reported. The literature regarding ameloblastic fibro- and odontosarcomas is reviewed. There have been 16 reported cases of ameloblastic fibrosarcoma and another six cases (one uncertain) of ameloblastic fibrosarcoma which showed induction of dentin or enamel and which therefore according to the WHO Classification should be separately classified as ameloblastic odontosarcomas. Our case showed no enamel and therefore is better called ameloblastic dentinosarcoma. Ameloblastic sarcomas of the jaws are of low grade malignancy, do not often metastasize, and if treated by radical resection have a good prognosis.

Adult↗
PubMed1976

Recurrent ameloblastoma of the mandible.

Ameloblastoma is by nature an invasive tumour and the full extent of the infiltration is not always appreciated when the lesion is being excised. Included in a series of 40 cases are 7 recurrent lesions. Pertinent clinical features of the 7 recurrent cases are discussed. A close study has been made of the recurrent tumours in the hope that some explanation could be found for the unsuccessful primary treatment. The investigation considered a number of aspects of the behavior of this growth and from this certain facts have emerged. Definitive treatment should not be embarked on before the diagnosis has been established. Only then can an overall plan of management be devised. It is noteworthy that the rate of growth of the lesion is more rapid in the younger age group. Ameloblastoma varies in it's clinical and radiological presentation. Primary treatment is influenced by the size and site of the particular lesion. The management of the recurrent lesion depends on the mode of presentation of the particular growth.

Adolescent↗
PubMed1976

Quantitative studies on the dispersal of skin bacteria into the air.

Dispersal of skin micro-organisms into the air during undressing was studied in 72 members of surgical and nursing staff. Few pathogens were found to be dispersed. Males dispersed more normal skin organisms than did females. Males were also more heavily colonised than females, and sex differences in dispersal diminished when allowance was made for the denser colonisation of males. Dispersal was correlated most strongly with the counts on the thighs and abdomen in males but on the shins in females.

Air Microbiology↗
PubMed1976

Binding of thiostrepton to ribosomes from thiostrepton-sensitive and -resistant Bacillus subtilis strains.

Binding of [(35)S]thiostrepton to ribosomes from thiostrepton-sensitive and -resistant strains of Bacillus subtilis was studied. Ribosomes from thiostrepton-resistant strains bound relatively little thiostrepton compared with ribosomes from thiostrepton-sensitive B. subtilis. In addition, ribosomes from revertant strains that were obtained as thiostrepton-sensitive revertants from thiostrepton-resistant strains bound [(35)S]thiostrepton similarly to ribosomes from the sensitive parental strain.

Anti-Bacterial Agents↗
PubMed1976

The concentration of 67Ga and 45Ca in the lactating mammary gland and its relevance to the tumor uptake of 67Ga citrate.

67Ga is known to concentrate in the breasts of pregnant and postpartum women, and a case is now described in which 67Ga uptake was seen in the breasts of a woman who was neither pregnant nor postpartum, but was receiving chemotherapy for Hodgkin's disease. Comparative studies of the uptake of 67Ga and 45Ca in lactating dogs have shown that both nuclides are secreted in the milk in similar amounts and in protein-bound form. The concentration of 67Ga in mammary tissue is about one-half of that found in the milk at 5 hr postinjection but, by 48 hr, the concentrations are approximately equal. There were similarities in the subcellular distributions of 67Ga and 45Ca in the lactating mammary gland at 5 and 48 hr. Although there was a correlation between 67Ga and 45Ca in individual pieces of a lactating mammary gland at 5 hr after injection, no such correlation was seen between the two nuclides in multiple samples of a transmissible venereal tumor measured at various time intervals. The rate of dispersion of 67Ga and 45Ca from the lactating mammary gland was similar but, in the tumor, 67Ga was present in very much greater amounts than 45Ca and was retained longer. It is concluded that, although there may be similarities in the metabolic pathways of gallium and calcium in the lactating mammary gland, there is no similarity in the mechanism of uptake of these two elements into tumors.

Animals↗
PubMed1975

New variant of phenylketonuria with progressive neurological illness unresponsive to phenylalanine restriction.

Three children, two of them siblings, with an unusual type of phenylketonuria are described. The three patients, two of them observed from the neonatal period, had a progressive neurological illness which was unlike that of classical phenylketonuria, and which did not respond to a low phenylalanine diet. The biochemical features suggested that the block in the conversion of phenylalanine to tyrosine was less severe than in the classical disease, and phenylalanine rho-hydroxylase activity, measured in one patient was normal. It is suggested that the patients have a disorder of biopterin metabolism possibly due to a defect of the enzyme dihydropteridine reductase.

Biopterins↗
PubMed1975

Comparison of an amino acid mixture and protein hydrolysates in treatment of infants with phenylketonuria.

This study compares three feeding regimens for infants with phenylketonuria diagnosed by neonatal screening. Group 1 (five children) received Minafen (Cow & Gate) until they weighed twice their birthweights; Aminogran (Allen & Hanbury) was then added to the feeds in increasing amounts and replaced Minafen at between 8 and 10 months of age. Group 2 (five children) received Aminogran from the neonatal period. Group 3 (five children) received Minafen until they weighed twice their birthweights; Cymogran (Allen & Hanbury) was then added in increasing amounts and replaced Minafen at between 8 and 10 months of age. In all three groups growth was normal and control of phenylalanine levels satisfactory. During the first few months of life the Aminogran regimen proved more complicated and caused more practical difficulties than the regimens starting with Minafen. Later in the first year, when mixed feeding was introduced, and particularly when the bottle was exchanged for the cup, Aminogran had advantages over Cymogran because of its low calorie content, small bulk, and less unpleasant taste. At this age feeding problems were fewer and easier to manage with Aminogran than with Cymogran. A method of using Aminogran in the management of such problems is described. For these reasons, the regimen fed group 1, in which Minafen is used initially and then replaced by Aminogran, is preferred to the other two.

Alkaline Phosphatase↗