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Biomedical subjects

D Sims

Publications and source records attributed to D Sims.

32 records · Page 2Linked to original sources
PubMed1986

Efficacy of repeated doses of levamisole, morantel, fenbendazole, and ivermectin against gastrointestinal nematodes in ewes.

Levamisole, morantel, fenbendazole, or ivermectin was administered at 2-week intervals from May 1 through Sept 14, 1985, to breeding ewes (20 ewes/drug) infected with various gastrointestinal nematodes. All ewes had fewer gastrointestinal nematode eggs per gram of feces (epg) after 2 treatments, compared with pretreatment epg counts. Ewes administered ivermectin continued to have a low mean epg (0 to 3) throughout the study. The mean epg counts of ewes treated with levamisole increased from 3 to 483 during the study. This increase was similar to that of ewes treated with morantel (7 to 485 epg). The mean epg count of fenbendazole-treated ewes increased from 4 to 192 during the study. By the end of the study, the mean epg counts when expressed as a percentage of the pretreatment epg counts were 4% (ivermectin), 249% (fenbendazole), 627% (levamisole), and 630% (morantel). With the exception of the ivermectin-treated ewes, the epg count increased almost linearly in the ewes after the 2nd anthelmintic treatment. These data indicate that the gastrointestinal nematodes (including Haemonchus contortus) may have developed more resistance to levamisole and morantel than to fenbendazole. On the basis of the epg counts, resistance to ivermectin did not develop during the 4.5-month treatment period. The percentage of ewes shedding eggs after 2, 4, and 6 anthelmintic treatments was lowest for ewes treated with ivermectin (20%) and was similar (40%) for ewes treated with 1 of the other 3 anthelmintics. At the conclusion of the study, most of the ewes (90%) were shedding at least a small number of eggs, regardless of the anthelmintic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Follicular cysts in sheep.

A flock of 188 sheep was surveyed for cutaneous lesions that were noticed 3 days after shearing. On the basis of histologic features of the cyst wall, ie, association with sebaceous glands and lack of follicular structures or rete pegs, the cysts were classified as follicular cysts.

Animals↗
PubMed1983

Protective effect of vitamin E on intraventricular haemorrhage in the newborn.

Forty-four consecutively born babies of birth weights under 1751 g were randomly selected to receive a daily intramuscular injection of vitamin E (all-rac-alpha-tocopheryl acetate) from the day of birth (Day 0) until Day 3, or were allocated to a non-supplemented control group. Frequent ultrasound examinations of the brain were made during the first week of life and babies were classified as having 'no haemorrhage', 'subependymal haemorrhage (SEH) only' or 'intraventricular haemorrhage' (IVH). The incidence of SEH or IVH was similar in supplemented (42.9%) and control babies (43.5%). SEH or IVH was observed only in babies of less than 32 weeks gestation; when only babies under 32 weeks were considered, IVH was less common in those supplemented (18.8%) than in the controls (56.3%). Babies with IVH had lower median plasma vitamin E concentrations when compared with babies without any haemorrhage and compared with those with only SEH. Three supplemented babies suffered IVH and they were the three with the lowest plasma vitamin E concentrations among the babies supplemented with vitamin E from Day 0 to Day 3. We speculate that vitamin E protects endothelial cell membranes of capillaries in the subependymal layer of the brain against oxidative damage and disruption and thereby limits the magnitude of haemorrhage in the subependymal layer, and reduces the risk of extension into the ventricles.

Cerebral Hemorrhage↗
PubMed1983

Antitumor agents LXIII: the effects of microlenin on nucleic acid and protein syntheses of Ehrlich ascites cells.

Microlenin, a novel dimeric sesquiterpene lactone isolated from Texas Helenium microcephalum, was shown to inhibit Ehrlich ascites carcinoma growth. Metabolic studies demonstrated that DNA synthesis and protein synthesis were significantly inhibited by two doses of microlenin at 5 mg/kg/day. DNA synthesis appeared to be blocked at several sites including DNA polymerase, purine synthesis, and dihydrofolate reductase. Thymidine nucleotide pools were significantly reduced by microlenin. Protein synthesis inhibition by microlenin appeared to occur during the initiation step of polypeptide synthesis. The metabolic effects of microlenin were similar to other sesquiterpene lactones in the Ehrlich ascites carcinoma cells. However, a lower dose of microlenin was required to bring about these metabolic effects when compared with other sesquiterpene lactones. Thus, microlenin may be a more likely therapeutic agent than helenalin which has demonstrated cellular toxicity.

Animals↗
PubMed1981

Antitumor agents XLII: Comparison of antileukemic activity of helenalin, brusatol, and bruceantin and their esters on different strains of P-388 lymphocytic leukemic cells.

Based on the fact that some known antineoplastic agents possess an ester moiety within their structure, the esters of helenalin, a sesquiterpene lactone, and of brusatol and bruceantin, quassinoids, were synthesized and tested for antileukemic activity in the P-388 screen. These agents gave different T/C% values dependent on the P-388 lymphocytic leukemia strain and the host strain of mice used. Later studies demonstrated that the agents caused different degrees of inhibition of nucleic acid and protein synthesis in the various P-388 strains. The higher the degree of inhibition of precursor incorporation into the nucleic acid or protein, the higher was the T/C% value obtained in a given P-388 strain. The study demonstrates the lack of consistency of P-388 lymphocytic leukemia cell lines used in various laboratories and indicates that the inbred strain of mice is a critical factor in the tolerance of drug toxicity and, thus, T/C% obtained.

Animals↗
PubMed1981

Antitumor agents. 44. Bis(helenalinyl) esters and related derivatives as novel potent antileukemic agents.

Bis(helenalinyl), bis(plenolinyl), bis(2,3-dihydrohelenalinyl), and bis(2,3,11,13-tetrahydrohelenalinyl) esters have been synthesized in an effort to elucidate the role of the two enone alkylating centers, beta-unsubstituted cyclopentenone and alpha-methylene gamma-lactone, as well as the significance of the diester linkage with respect to the enhanced in vivo P-388 lymphocytic leukemia antileukemic activity of bis(helenalinyl) malonate (2) against P-388 lymphocytic leukemia in the mouse. The bisesters (2-5; 7, 8; 10, 11) are, in general, more potent and less toxic than their corresponding parent alcohols (1, 6; 9; 14). The beta-unsubstituted cyclopentenone ring and the alpha-methylene gamma-lactone moiety in the bisesters play important roles for the enhancement of the P-388 antileukemic activity. Removal of the enone double bonds in both alkylating centers of 2 gave rise to inactive compounds. Except for 2, the potent antileukemic activity of the bis(helenalinyl) esters (3-5) appears to be independent of the ester chain length.

Animals↗
PubMed1980

Antitumor agents XXXVI: Structural elucidation of sesquiterpene lactones microhelenins-A, B, and C, microlenin acetate, and plenolin from Helenium microcephalum.

The antitumor sesquiterpene lactones microhelenins-A, B, and C, microlenin acetate, and plenolin were isolated from Helenium microcephalum. The structures and stereochemistry of these lactones were determined by physical methods as well as by chemical transformations and correlations. Microlenin acetate appears to be the first novel dimeric sesquiterpene lactone demonstrated to have significant antileukemic activity.

Acetylation↗
PubMedDate not supplied

Antitumor agents 37. The isolation and structural elucidation of isohelenol, a new antileukemic sesquiterpene lactone, and isohelenalin from Helenium microcephalum.

The known compound isohelenalin (1) was isolated from Helenium microcephalum and the previously reported structure confirmed on the basis of physicochemical data and chemical transformation. In addition, a new antileukemic sesquiterpene lactone, isohelenol (2), was isolated and its structure elucidated.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

Bacteriology of diabetic foot ulcers.

Diabetic foot ulcerations exhibit a wide range of the bacterial spectrum. A long-standing question is whether any particular bacterium or class of bacteria is responsible for the more involved ulcers. A review of such cases at Sheridan Park Hospital reveals that there may be factors other than bacterial type that may account for the virulence of diabetic ulcers. Multifactorial causes host a vital role in this common, but potentially serious, podiatric problem.

Bacteria↗