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Biomedical subjects

D W Roberts

Publications and source records attributed to D W Roberts.

At least 199 records · Page 11Linked to original sources
PubMed1976

Effects of two cetylpyridinium chloride-containing mouthwashes on bacterial plaque.

The purpose of this single blind clinical study was to determine the effects of two commerical mouthwashes (one containing cetylpyridinium chloride and domiphen bromide and the other containing only cetlypridinium chloride) on existing plaque accumulations. A second purpose was to determine if a residual effect could be shown 2 weeks after cessation of using these mouthwashes. A total of 120 adult subjects, who had been divided into three groups, were initially in the study. For a period of 31 days, the subjects in Group A rinsed with a commercial mouthwash containing cetylpyridinium chloride and domiphen bromide; Group B rinsed with a commercial mouthwash containing only ceytlpyridinium chloride; and Group C served as controls and rinsed with colored flavored water. All subjects continued their normal home oral hygiene practices, except that mothwashes other than as assigned were forbidden. The subjects received three identical examinations to determine their plaque scores. The examinations were conducted the day preceding initiation; the day following cessation; and 15 days after cessation of the rinsing procedures. A total of 105 subjects received the first and second examinations, and 93 subjects received all three examinations. Based upon the data obtained, the daily use of each of the cetylpyridinium chloride mouthwashes tested, appears to be partially effective in reducing existing bacterial plaque accumulations. The cetylpyridinium chloride-domophen bromide product was slightly, but not significantly, more effective than the other commercial mouthwash. Neither commerical product demonstrated a significant residual effect 2 weeks after cessation of use.

Adolescent↗
PubMed1975

RNA polymerase activity of Amsacta moorei entomopox virions.

Optimum conditions for in vitro RNA synthesis by the entomopoxvirus from Amsacta moorei, except for a temperature optimum of 26 degrees, were similar to those reported for vaccinia. Incorporation of 3H-ATP in the presence of CTP, GTP and UTP was significantly inhibited by actinomycin D; incorporation of 3H-ATP alone was not. The products formed by incorporation of 3H-ATP alone or with the three other nucleotides contained polyadenylic acid sequences. The sedimentation coefficient of the 3H-ATP-labeled product formed in the presence of CTP, GTP and UTP was reduced from 8-23S to 3-5S after RNase treatment. The product formed from 3H-ATP alone had an apparent sedimentation value of 3-5S.

Cell-Free System↗
PubMed1975

Inhibition by 4'-demethyl-epipodophyllotoxin 9-(4,6-O-2-thenylidene-beta-D-glucopyranoside) of human lymphoblast cultures in G2 phase of the cell cycle.

4'-Demethyl-epipodophyllotoxin 9-(4,6-0-2-thenylidene-beta-D-glucopyranoside) is a semisynthetic derivative of podophyllotoxin with oncolytic activity against a variety of neoplasms, Unlike the parent compound and other derivatives, which cause methaphase arrest, 4'-Demethyl-epipodophyllotoxin 9-(4,6-0-2-thenylidene-beta-D-glucopyranoside) apparently blocks the entry of CCRF-CEM cells into mitosis by inhibiting cells in the G2 phase of the cell cycle. The inhibition of precursor incorporation into DNA, RNA, and the protein, if observed, was delayed and probably secondary to inhibition of cells in the G2 phase of the cell cycle.

Cell Count↗
PubMed1975

Acute, chronic and terminal toxicity to 4'-demethylepipodophyllotoxin thenylidene glucoside (VM26) in mice.

The development of toxicity to 4'-demethylepipodophyllotoxin-9-(4,6,-O-thenylidene-beta-glucopyranoside) an epipodophyllotoxin with oncolytic activity, was characterized in mice treated three times at 3-day intervals with 10 mg of drug i.p. per kg of body weight. Changes in organ function and general metabolism were determined by measuring 18 constituents of blood for up to 10 weeks after drug administration. The results indicate three distinct phases of toxicity to 4'-demethylepipodophyllotoxin 9-(4,6-O-2-thenylidene-beta-glucopyranoside). Acute toxicity developed within the first 10 days and was expressed by a depressed hematocrit and elevated plasma levels of glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, lactic dehydrogenase, amylase, lipase, and uric acid. By 4 weeks, levels ahd returned to normal. The acute phase was followed by a chronic phase, which was characterized by progressive decreases in plasma levels of glucose, cholesterol, albumin, and total protein. Finally, about 7 weeks after treatment, a terminal phase indicated by correlated increases in glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, lactic dehydrogenase, and blood urea nitrogen became apparent. Plasma levels of creatine phosphokinase, calcium, inorganic phosphate, total bilirubin, ketones, and alkaline phosphatase did not change. Although the pancreas liver and marrow were all affected during acute toxicity, boserved changes in blood components during the chronic and terminal phases correlate best with continued hepatotoxicity. The present evidence on delayed toxicity to 4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) is most compatible with irreversible hepatotoxocity which leads to metabolic deficiencies and terminates in death of mice.

Alanine Transaminase↗