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Biomedical subjects

D Owen

Publications and source records attributed to D Owen.

At least 145 records · Page 8Linked to original sources
PubMed1975

Eimeria falciformis (Eimer, 1870) in specific pathogen free and gnotobiotic mice.

The endogenous and exogenous stages of a species of murine Eimeria were examined and compared with descriptions of other species isolated from Mus musculus. Developing stages of the parasite were found in the epithelial cells of the caecum and colon. Three asexual generations were observed, the third becoming apparent on the fourth day concurrently with gametogeny. The total length of the prepatent period was 5 days. Oocysts of the coccidian, identified as Eimeria falciformis, were administered to a group of germfree mice. Despite a dose level of 1 x 10(6), the coccidium was not established. Histological examination indicated the failure of the sporozoite to penetrate its host epithelium. The possible causes of this phenomenon were discussed.

Animals↗
PubMed1975

A method of removing starch powder from surgeons' gloves.

A method of washing the outside of surgeons' gloves with cetrimide is described. Experiments on animals showed that the method resulted in a considerable reduction in the amount of intraperitoneal contamination by starch powder.

Animals↗
PubMedDate not supplied

Toxicology of n-pentane (CAS no. 109-66-0).

n-Pentane (CAS no. 109-6-0) is a hydrocarbon solvent with an estimated production volume of 50000 metric tons in Europe. The present work was carried out to strengthen the toxicological information available for regulatory decision-making, particularly product classification, occupational exposure limits and risk assessment. The work described in this report was sponsored either by the Pentane Special Interest Group under the auspices of the Hydrocarbon Solvent Producers Association of CEFIC (European Chemical Industry Council) or by Exxon Chemical Europe. The following results were obtained: n-pentane was not acutely toxic by oral or inhalation routes, it was not a skin or eye irritant and did not induce skin sensitization. It did not exhibit cumulative toxicity at levels up to 20000 mg m(-3), which is approximately one-half of the lower explosive limit and the highest level considered safe to test. It did not induce developmental toxicity and was not mutagenic. From this and other existing information, it is concluded that n-pentane does not require classification for potential toxic hazards (as defined by Annex VI of the EU Dangerous Substance Directive, 1993), although the physical properties indicate that it would be appropriate to warn for the potential for aspiration. Further, there is no reason to reduce the current occupational exposure recommendations. Finally, although there are some safety issues relating to the flammability of n-pentane, the absence of any demonstrable toxicity at high treatment levels indicates that the risk of adverse health effects is minimal for all segments of the population.

Administration, Inhalation↗
PubMedDate not supplied

Bismuth-based triple therapy with bismuth subcitrate, metronidazole and tetracycline in the eradication of Helicobacter pylori: a randomized, placebo controlled, double-blind study.

OBJECTIVE: To determine the rate of Helicobacter pylori eradication following bismuth-based triple therapy with colloidal bismuth subcitrate, tetracycline hydrochloride and metronidazole. PATIENTS AND METHODS: One hundred and eleven patients were randomly assigned, in a two to one ratio, to colloidal bismuth subcitrate 120 mg qid plus metronidazole 250 mg qid plus tetracycline 500 mg qid (Gastrostat), or matching placebo tablets and capsules for 14 days. Presence or absence of H pylori was documented by histology at entry and at least 28 days after treatment. Patients had dyspeptic symptoms with or without a history of peptic ulcer. Patients with any previous attempt(s) at eradication of H pylori, who used bismuth, antibiotics, H2 receptor antagonists or proton pump inhibitors in the previous four weeks were excluded. RESULTS: Fifty-three of 59 (90%) patients on bismuth-based treatment and only one of 35 (3%) on placebo achieved eradication by per protocol analysis. Fifty-three of 65 (82%) patients on bismuth-based treatment achieved eradication, while only two of 34 (5%) achieved eradication on placebo by intention to treat analysis. Eradication rates for bismuth-based treatment across sites ranged from 83% to 100%. Only two patients in the bismuth-based treatment group (4%) and one in the placebo group (3%) discontinued treatment because of adverse events. CONCLUSIONS: Colloidal bismuth subcitrate plus metronidazole plus tetracycline, given in the doses studied for 14 days, is safe and highly effective against H pylori infection and would be appropriate as a first-line therapy for eradication.

Adolescent↗
PubMedDate not supplied

Investigation of the Mek-MAP kinase-Rsk pathway in human breast cancer.

BACKGROUND: Mitogenic signaling through the principal growth factor receptor tyrosine kinase (RTK) pathway, i.e. RTK-->Ras-->Raf-->Mek-->MAPK has been implicated in the pathogenesis of human cancer. However, biochemical characterization of this has not been adequately assessed in human cancers. MATERIALS AND METHODS: Using extracts from 23 human breast cancers and control tissue from the same resected specimens, the protein levels, phosphotransferase activities and subcellular locations of the mitogen-activated protein (MAP) kinase isoforms p42 Erk2 and p44 Erk1 were examined, together with their phosphotransferase activities towards myelin basic protein (MBP) and a peptide substrate patterned after the Thr-669 site in the epidermal growth factor receptor (EGFR T669) that is phosphorylated by MAP kinase. RESULTS: Overexpression of both Erk2 and Erk1 isoforms was evident using specific antibodies. A universal activation of MBP and EGFR T669 peptide phosphotransferase activities was also found (up to 3-fold). MonoQ fractionation resolved the bulk of the EGFR T669 peptide phosphorylation from elution of the MAP kinase protein. Erk1 and Erk2 activities determined by specific immunoprecipitation were increased by up to only 2.5-fold in only 50% of tumors overall. Immunohistochemical studies, using a monoclonal antibody specific for Erk2 demonstrated that the cellular distribution of this MAP kinase was similar in both control and tumor tissues, and Erk2 was largely confined to normal and malignant acini, whilst the intensity of staining was actually reduced in the tumor tissue. Mek1 and especially Mek2 protein expression, as well as MAP kinase kinase activity as determined by phosphorylation of kinase-inactive Erk [GST-K71A] were increased in cancer samples. CONCLUSIONS: a) This confirms that MAP kinase activity is increased in human breast cancer. However, the frequency and magnitude of this change is dependent upon the chosen methodology (i.e. crude lysate assays versus specific immunoprecipitation). b) A MAP-kinase-independent source of increased EGFR T669 phosphotransferase activity in tumor extracts has been demonstrated for the first time in human breast cancer. c) By immunohistochemistry, Erk2 protein was actually found to exhibit lower intensity in tumor samples; the increased expression was most likely due to its increased distribution. d) Increased Mek protein expression and activation have been demonstrated for the first time in human breast tumors.

Anion Exchange Resins↗
PubMedDate not supplied

Celiac sprue and ulcerative colitis in three South Asian women.

The association of celiac disease and inflammatory bowel disease has not been described in females of South Asian descent. We report three women, aged 33, 43 and 46 years, of South Asian origin, with both ulcerative colitis and celiac disease.

Adult↗