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Biomedical subjects

S Hamilton

Publications and source records attributed to S Hamilton.

At least 145 records · Page 8Linked to original sources
PubMed1978

Psychological test performance and sedation thresholds of elderly dements, depressives and depressives with incipient brain change.

As expected, dements, depressives and patients with a mixed psychopathology were differentiated from one another on the sedation threshold measure and on a number of psychological tests. In depressives responding to treatment significant changes in physiological and psychological measures, which had been reported in an earlier study could not be replicated except for an increase of psychomotor speed. In the present sample of patients there were significant correlations between various psychological measures and between them and the levels of the sedation threshold, suggesting that sedation thresholds and psychological tests measured related cerebral functions. Evidence obtained from the earlier investigations to the effect that cerebral age changes short of those occurring in dementia may facilitate the occurrence of depression in late life was only weakly confirmed by the replication study.

Aged↗
PubMed1977

The effect of cyclandelate in depressed and demented patients: a controlled study in psychogeriatric patients.

In a double-blind clinical trial the effects of the vasodilator drug cyclandelate (in a dose of 1200 mg daily) were studied in a group of patients with depressive illnesses or dementing conditions. The measures used before treatment and after six weeks' treatment were: clinical rating, psychometric tests (Paired Associate Learning Test, Digit Copying Test, Digit Substitution Test, and Serial Learning Test), cortical evoked potentials, the sedation threshold and the Gresham Questionnaire. In the depressive group there were no significant differences in the changes in scores at six weeks in three groups: those who received cyclandelate plus amitriptyline, those who received placebo plus amitriptyline, and those who received neither placebo nor cyclandelate. In the demented group there were significant changes in favour of the placebo on two measures (Digit Copying test, and one component of the auditory evoked response). The results do not support the previously reported views claiming, in a number of studies, a significant improvement in the performance of both demented and normal elderly subjects treated with cyclandelate. The significance of these findings is discussed.

Aged↗
PubMed1977

Cyproheptadine inhibition of stimulated plasma renin activity.

Plasma renin activity (PRA) was stimulated by oral frusemide (60 mg) in 4 normal male subjects. Cyproheptadine (Periactin), a serotonin antagonist, was then administered (2 mg orally four times daily) for 7 days and the PRA response to frusemide re-evaluated in the 4 subjects. A highly significant mean inhibition (P less than 0.01) of frusemide stimulated PRA was demonstrated after cyproheptadine administration. Our results show that serotonin, presumably acting via central pathways, may play a role in renin regulation and that this pathway can be inhibited by cyproheptadine.

Adult↗
PubMed1976

The growth of respiratory syncytial virus in organ cultures of bovine foetal trachea.

Respiratory syncytial (RS) virus grown in organ cultures of bovine foetal trachea at 37 degrees C and pH 7.2 reached maximum titres of up to 1 X 10(5) PFU/ml between 11 and 21 days after inoculation. Virus yield was increased three fold by incubation at 33 degrees C, but depressed by the addition of RS virus antiserum, with or without bovine complement, or by the addition of alveolar macrophages. Variation in pH or the concentration of foetal calf serum and magnesium chloride did not affect the virus yield. Virus growth did not affect ciliary activity of the cultures. Histological changes involved slight flattening of the epithelium and the appearance of phloxinophilic inclusion bodies. Fluorescent antibody staining showed more virus antigen in the peri-tracheal connective tissue than in the ciliated epithelium. The presence of non-cytopathic mucosal disease (MD) virus in RS virus infected organ cultures slightly depressed RS virus growth but did not influence ciliary activity. These in vitro experiments suggest that the tracheal epithelium may not be an important target in the pathogenesis of RS virus infection in vivo.

Animals↗
PubMed1976

Properties of condensed bacteriophage T4 DNA isolated from Escherichia coli infected with bacteriophage T4.

Methods developed for isolating bacterial nucleoids were applied to bacteria infected with phage T4. The replicating pool of T4 DNA was isolated as a particle composed of condensed T4 DNA and certain RNA and protein components of the cell. The particles have a narrow sedimentation profile (weight-average s=2,500S) and have, on average, a T4 DNA content similar to that of the infected cell. Their dimensions observed via electron and fluorescence microscopy are similar to the dimensions of the intracellular DNA pool. The DNA packaging density is less than that of the isolated bacterial nucleoid but appears to be roughly similar to its state in vivo. Host-cell proteins and T4-specific proteins bound to the DNA were characterized by electrophoresis on polyacrylamide gels. The major host proteins are the RNA polymerase subunits and two envelope proteins (molecular weights, 36,000 and 31,000). Other major proteins of the host cell were absent or barely detectable. Single-strand breaks can be introduced into the DNA with gamma radiation or DNase without affecting its sedimentation rate. This and other studies of the effects of intercalated ethidium molecules have suggested that the average superhelical density of the condensed DNA is small. However, these studies also indicated that there may be a few domains in the DNA that become positively supercoiled in the presence of high concentrations of ethidium bromide. In contrast to the Escherichia coli nucleoid, the T4 DNA structure remains condensed after the RNA and protein components have been removed (although there may be slight relaxation in the state of condensation under these conditions).

Bacterial Proteins↗
PubMed1974

Cell-mediated immunity to intrinsic factor in autoimmune disorders.

Evidence of cell-mediated immunity to gastric intrinsic factor was present in 86% of patients with pernicious anaemia and in at least 13% of patients with hyperthyroidism, 21% of patients with atrophic gastritis, and four out of nine (46%) patients with hypogammaglobulinaemia. Controls gave negative results. The four patients with hypogammaglobulinaemia and cell-mediated immunity to intrinsic factor had evidence of impaired gastric function.

Agammaglobulinemia↗