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Biomedical subjects

R Hamilton

Publications and source records attributed to R Hamilton.

At least 127 records · Page 7Linked to original sources
PubMed1977

Effect of respiratory syncytial virus infection of HeLa-cell macromolecular synthesis.

Cells infected with respiratory syncytial (RS) virus eventually die but there appears to be no specific mechanism for shutting off cellular synthesis of macromolecules. DNA and RNA synthesis, as measured by the incorporation of labelled thymidine or uridine, do not begin to shut down until some time between 11 and 18 h after infection. By 18 h their rates of synthesis are reduced to approx. 50% for DNA and 35% for RNA. Protein synthesis continues throughout the course of infection at approximately the same rate. Synthesis of most of the cellular polypeptides also continues, but the distribution of polypeptides of high and low mol. wt. shifts. The increase in the proportion of those of high mol. wt. includes a peak that represents one of the seven previously identified virion polypeptides. Another consequence of RS virus infection is an increase in glucosamine incorporation, beginning near the end of the virus eclipse period (12 h after infection), which may be associated with virion glycoprotein synthesis. Polyacrylamide-gel electrophoresis of glucosamine-labelled cells reveals that at 18 h after infection two of the three previously identified virion glycoproteins are present.

Cell Survival↗
PubMed1977

Activities of various 4-aminoquinolines against infections with chloroquine-resistant strains of Plasmodium falciparum.

The studies reported here stemmed from a personal report by Geiman on the capacity of the 4-aminoquinoline amodiaquin to inhibit in vitro maturation of ring stages of the chloroquine-resistant Monterey strain of Plasmodium falciparum. This observation, confirmed in owl monkeys infected with this strain, led to a comparison of the activities of chloroquine, amodiaquin, amopyroquin, and dichlorquinazine (12,278 RP) against infections with various chloroquine-susceptible and chloroquine-resistant strains. The results showed that: (i) these 4-aminoquinolines were essentially equally active against infections with chloroquine-susceptible strains and (ii) the activities of amodiaquin, amopyroquin, and dichlorquinazine were reduced significantly in the face of chloroquine resistance, but (iii) well-tolerated doses of these compounds would cure infections with strains that fully resisted treatment with maximally tolerated doses of chloroquine. Two other 4-aminoquinolines, SN-8137 and SN-9584, which also exhibited activity against chloroquine-resistant parasites in vitro, displayed curative activity in monkeys infected with a chloroquine-resistant strain. These observations show that there is cross-resistance among the 4-aminoquinolines, confirming earlier findings, but indicate that the dimensions of this phenomenon are sufficiently limited so that some derivatives are therapeutically effective against infections refractory to maximally tolerated doses of chloroquine.

Aminoquinolines↗
PubMed1977

Acid-base balance and plasma composition in the aestivating lungfish (Protopterus).

Upon entering into aestivation, Protopterus aethiopicus develops a respiratory acidosis. A slow compensatory increase in plasma bicarbonate suffices only to partially restore arterial pH toward normal. The cessation of water intake from the start of aestivation results in hemoconcentration and marked oliguria. The concentrations of most plasma constituents continue to increase progressively, and the electrolyte ratios change. The increase in urea concentration is disproportionately high for the degree of dehydration and constitutes an increasing fraction of total plasma osmolality. Acid-base and electrolyte balance do not reach a new equilibrium within 1 yr in the cocoon.

Acclimatization↗
PubMed1977

Clinical, laboratory, and epidemiologic features of a viral gastroenteritis in infants and children.

We studied 27 infants admitted to the hospital with acute diarrhea caused by human rotavirus (HRV) and obtained additional data on fecal excretion from ten outpatients with the same infection. The disease was characterized by watery diarrhea with fever and vomiting at the onset, isotonic dehydration, compensated metabolic acidosis, and increased concentrations of sodium and chloride but low concentrations of sugar in stools. Diarrhea usually ceased in three to four days when oral feedings were reduced or stopped but recurred mildly in four patients. Of 57 household contacts, 12 were symptomatic, 6 had HRV in their stools, and 19 had significantly increased serum HRV antibody titers. These features of the disease accord with available information on the pathogenesis of HRV infection. Knowledge of the clinical pattern of this newly diagnosable infection should help physicians to recognize and treat quickly this highly infectious, potentially dangerous illness.

Adult↗
PubMed1973

Subacute sclerosing panencephalitis measles virus: study of biological markers.

Comparative studies between two measles virus strains isolated from patients with subacute sclerosing panencephalitis (SSPE) and a prototype low tissue culture passage Edmonston measles virus are described. Differences were noted in several properties. The findings described in this report suggest that strains of measles virus associated with SSPE have different biological properties and apparently cannot be distinguished from laboratory and field strains of the virus.

Animals↗