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Biomedical subjects

J G Bell

Publications and source records attributed to J G Bell.

68 records · Page 4Linked to original sources
PubMed1977

An elementary study of deformation of molar teeth during amalgam restorative procedures.

A technique using an optical comparator was employed to examine the dimensional changes resulting from cavity preparation, application of the matrix and packing with amalgam in three extracted molar teeth. The changes have been reported and the nature of the change discussed. A modification in the use of the matrix and amalgam packing technique is suggested.

Dental Amalgam↗
PubMed1975

Transformation by a temperature sensitive mutant of Rous sarcoma virus in the absence of serum.

Cultures of chicken embryo fibroblasts infected with the temperature-sensitive transformation mutant of Rous sarcoma virus, tsLA24PR-A, were arrested between mitosis and S phase by exposure to serum-free medium at the non-permissive temperature (41degree C) for 2 days. On shifting to the permissive temperature (35degree C) the cells assumed a transformed morphology and increased uptake of [2minus 3H]-Deoxy-glucose. There was a concomitant increase in acid insoluble [3H]-thymidine. This suggests that the virus transforming function can cause stationary cells to enter their growth cycle. The level of release of infectious virus was shown to decrease on cell cycle arrest in serum-free medium and not to recover on a shift to 35 degrees, when cellular DNA synthesis and transformation was induced. Cultures rendered stationary in medium containing serum depleted of multiplication stimulating factor did not show this reduction in virus production.

Animals↗
PubMed1975

Genetic recombination among temperature-sensitive mutnats of Rous sarcoma virus.

Genetic recombination of RSV has been studied, using ts mutations in both initiation and maintenance of transformation as markers. The progeny of a single cycle of mixed infection appears to contain no recombinants, but yields heterozygous particles or viral clumps. On subsequent cycles of infection some of these heterozygotes/clumps persist, but they also segregate recombinant viruses. Some of the markers in these recombinants show evidence of linkage and thus probably recombine by intramolecular exchanges. Studies of td ts mutants (the class most frequently isolated from stock virus) show that recombination between them occurs at a level sufficient to explain cooperative transformation by these viruses. Furthermors, this genetic recombination is probably a necessary prerequisite for cooperative transformation since complementation between the mutants is absent or inefficient. The simplest explanation for this apparent lack of complementation is that the td ts mutants are all derived by lesions in the same cistron.

Avian Sarcoma Viruses↗
PubMedDate not supplied

Red blood cell fatty acid compositions in a patient with autistic spectrum disorder: a characteristic abnormality in neurodevelopmental disorders?

The fatty acid compositions of red blood cell (RBC) phospholipids from a patient with autistic spectrum disorder (ASD) had reduced percentages of highly unsaturated fatty acids (HUFA) compared to control samples. The percentage of HUFA in the RBC from the autistic patient was dramatically reduced (up to 70%) when the sample was stored for 6 weeks at -20 degrees C. However, only minor HUFA reductions were recorded in control samples stored similarly, or when the autistic sample was stored at -80 degrees C. A similar instability in RBC HUFA compositions upon storage at -20 degrees C has been recorded in schizophrenic patients. In a number of other neurodevelopmental conditions, including attention deficit hyperactivity disorder (ADHD) and dyslexia, reduced concentrations of RBC HUFA have been recorded. The extent and nature of these aberrations require further assessment to determine a possible common biochemical origin of neurodevelopmental disorders in general. To facilitate this, a large scale assessment of RBC fatty acid compositions in patients with ASD, and related disorders, should be performed as a matter of urgency. Supplementing cells in culture with the tryptophan metabolite indole acrylic acid (IAA) affected the levels of cellular HUFA and prostaglandin production. Indole acroyl glycine (IAG), a metabolite of IAA excreted in urine, is found in high concentrations in patients with neurodevelopmental disorders including ASD, ADHD, dyslexia, Asperger's syndrome and obsessive compulsive disorder.

Asperger Syndrome↗
PubMedDate not supplied

Velogenic viscerotropic Newcastle disease virus strains in Morocco.

Isolates of Newcastle disease virus (NDV) in Morocco were characterized as velogenic. Two isolates were from tracheal swabs taken at a Moroccan live poultry market, and four isolates were from field cases. Infection of 8-week-old chickens showed that these isolates and previously characterized Moroccan isolates were of the viscerotropic pathotype. Based on hemagglutinin thermostability and the capacity to agglutinate equine erythrocytes, the Moroccan velogenic viscerotropic NDV isolates were classified as belonging to at least three distinct strains.

Animals↗
PubMedDate not supplied

Isolation and biological properties of some Moroccan strains of Newcastle disease virus.

Newcastle disease virus was isolated from six field cases in Morocco. On the basis of the mean death time of chicken embryos, the intracerebral pathogenicity index, and plaque formation on chicken embryo fibroblast monolayers, five isolates were determined to be of the velogenic pathotype. One of these differed from the others in that it agglutinated equine erythrocytes. The sixth isolate was found to be of low virulence but differed from the vaccinal strain tested.

Animals↗