Biomedical subjects
Publications and source records attributed to J Holton.
Forty strains of Helicobacter pylori had an MIC(50) of 4 mg/L of the non-absorbably antibiotic, rifaximin. Neither synergy nor antagonism was demonstrated when the drug was combined with ampicillin, metronidazole and omeprazole and the rate of spontaneous mutation was less than 1 in 10(8). With these in-vitro characteristics, rifaximin should now be assessed for clinical efficacy.
Perceptions of functioning levels of baccalaureate students nearing graduation were assessed, comparing views of 15 educators, 15 health department administrators, and 185 students. A modified list of the 47 essential public health nursing competencies identified through the U. S. Department of Health and Human Services Division of Nursing served as the basis for data collection and analyses. Student competencies in individual skills were ranked higher than group and community competencies by all three groups surveyed. Students ranked competencies at higher levels than educators and educators at higher levels than administrators. Although administrators continue to advise new graduates to work in acute care before entering community health, support for continuation of this practice was not observed based on administrator ratings.
OBJECTIVES: To compare the seroprevalence of Helicobacter pylori in gastric and nongastric carcinoma patients and to investigate the relationship between H. pylori, gastric cancer site, and histological type. METHODS: In a 24-month period, 307 gastric cancer patients (male/female: 185/122; age range 19-94 yr, mean 69 yr) were investigated by serology (IgG to H. pylori), histology, and urease test for H. pylori. One hundred and seventy-seven gastric cancers were in the antrum, 98 were in the corpus, and 32 were in the fundus; 227 were intestinal and 80 were diffuse type. In the same study period, we assessed the H. pylori seroprevalence in 162 patients with nongastric carcinoma (lung n = 41, breast n = 42, genitourinary n = 41, GI tract n = 22, others n = 16) (male/female: 84/78; age range 31-81 yr, mean 56 yr). RESULTS: The overall seroprevalence of H. pylori in gastric cancer and in nongastric cancer was 82 and 56%, respectively (p < 0.001). In asymptomatic blood donors (age range 55-65 yr) and in dyspeptic patients older than 60 yr, a seroprevalence of 55 and 58% was found, respectively, which is significantly lower (p > 0.001) than the gastric cancer patients but similar to the nongastric cancer population. No difference was found in the H. pylori status according to the gastric cancer site (83, 82, and 81% in the antrum, corpus, and fundus, respectively). Two hundred and twenty-seven gastric cancers [185 (81%) H. pylori-positive] were found to be of an intestinal type and 80 [66 (82%) H. pylori-positive] of a diffuse type (not significant). No age-related difference (below and above 60 yr) in H. pylori prevalence was observed within each cancer population, and, in both age groups, the seroprevalence of infection was higher in gastric cancer patients (86 and 81%) than in nongastric cancer patients (56 and 56%) (below and above 60 yr, respectively). CONCLUSION: H. pylori seroprevalence is significantly higher in gastric cancer compared with nongastric cancer patients. No differences were observed in H. pylori seroprevalence according to gastric cancer site or histological type. The higher H. pylori seroprevalence in gastric cancer patients is not age related.
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OBJECTIVES: to determine and compare the microbial retention efficiency of 3 types of heat and moisture exchange (HME) filters. DESIGN: randomised prospective study. SETTING: Intensive Care Unit at the Middlesex Hospital and the microbiology laboratory of the Department of Academic Microbiology, University College London Medical School. MEASUREMENTS AND RESULTS: An aerosol challenge to each filter using a suspension containing. S. marcescens and the bacteriophage MS2. In total 45 filters of 3 types were tested, 15 previously unused and 30 that had been used in ventilator circuits of 30 patients. The 3 types of filter generally had microbial retention efficiencies of > 99.99% for both S. marcescens and the bacteriophage MS2. CONCLUSION: The 3 types of HME filter were effective microbial filters and comparable in their microbial retention.
We have tested the in-vitro efficacy of various disinfectants against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium-intracellulare, and against the protozoon Cryptosporidium parvum. The disinfectants were tested both with and without an organic load. 'Sactimed sinald' (a quaternary ammonium compound), 'Steris 20' (a peracetic acid compound) and 'Pentapon DC1' (a beta-ene compound) were all equally as effective as 'Cidex' (glutaraldehyde) against all the mycobacteria tested, as well as C. parvum. 'Virkon' (a per-oxygen compound) and 'Phoraid' (an iodine compound) were less effective than glutaraldehyde. 'Pentapon DHY' (a beta-ene compound) was ineffective against any of the organisms tested. We have also assessed a method of determining disinfectant efficacy using [35S]-methionine labelling of proteins, which appears promising, although it requires further evaluation.
An outbreak of infections with non-encapsulated Haemophilus influenzae, resistant to ampicillin, chloramphenicol, sulphonamide and tetracycline involved 13 elderly patients and three nurses on acute admission and care of the elderly wards. Thirty-two isolates were found to be indistinguishable on analysis of biotype, antibiogram, serotype and major outer membrane proteins (MOMP). Plasmids could not be identified in the original isolates but after mating with a Rec A H. influenzae recipient, the resultant transconjugates were found to harbour either a 72 kilobase pair (kB) plasmid coding for resistance to chloramphenicol, ampicillin, sulphonamide and tetracycline or a 65 kB plasmid coding for resistance to chloramphenicol, ampicillin and sulphonamide. Both plasmids yielded virtually indistinguishable restriction digest patterns. This suggests that the tetracycline resistance gene (Tc gene) is a non-essential component of one basic plasmid responsible for the multiple antibiotic resistances seen in the strains recovered during the outbreak. This illustrates the value of plasmid profiles to compare strains of non-encapsulated H. influenzae, and suggests that plasmid restriction enzyme analysis is critical.
The Wolf 35100 and DSD-91 endoscope disinfection machines were compared. Using a total viable count method, the degree of contamination of an Olympus GIFXQ20 endoscope was assessed following inoculation with a suspension of Pseudomonas aeruginosa and again following disinfection cycles in each machine, using 2% glutaraldehyde as the disinfectant. Both machines performed satisfactorily, with an average reduction of between 7 and 8 log10 cfu ml-1 P. aeruginosa following disinfection. The dilution effect on the glutaraldehyde of repeated disinfection cycles was also assessed for each machine. After 40 cycles in the DSD-91 and 25 cycles in the Wolf 35100 machines, the dilution of glutaraldehyde may give rise to concern, especially if adequate pre-cleaning of the endoscope is not carried out. The DSD-91 machine has certain advantages over the Wolf 35100 in terms of endoscope capacity, running costs and ease of maintenance. Both machines give similar results for endoscope disinfection.
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This study aimed to determine the importance of raised antibodies to Helicobacter pylori in an asymptomatic population. A total of 128 asymptomatic blood donors who were seropositive for H pylori and consented to endoscopy were investigated. These subjects were from a population of 1010 blood donors screened for antibodies to H pylori. A questionnaire was completed to determine if any subjects had complained of symptoms, and they subsequently had endoscopy. Altogether 121 of 128 were positive for H pylori by histology and urease test and/or culture and all 121 had chronic active gastritis on histology. Twenty five of these subjects had peptic ulcer (20 duodenal, five gastric), a further 21 had erosive duodenitis, and two were found to have gastric cancer. H pylori associated peptic ulcer disease and duodenitis occur more frequently than previously recognised and this suggests that H pylori infection, even if asymptomatic, is of far greater clinical relevance than originally thought.
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OBJECTIVES: To determine the concentrations of interleukin-1 beta, interleukin-6, and interleukin-8 in tissue homogenates of mucosal biopsy specimens from Helicobacter pylori-positive and -negative patients. METHODS: In 43 consecutive patients who underwent upper gastrointestinal endoscopy, seven antral biopsies were taken; three specimens were used for cytokine determination and the remaining four biopsies were processed for H. pylori detection. Peripheral venous blood was collected and IgG to H. pylori was assayed by an ELISA technique. RESULTS: Twenty-nine of 43 patients (67%) were histologically positive for H. pylori; all had chronic gastritis. The mucosal levels of interleukin-6 and interleukin-8 were significantly higher in H. pylori-positive patients than in the negative patients (p < 0.001). A significantly higher percentage of interleukin-8 was found in patients colonized by H. pylori with active superficial chronic gastritis (85.7%), compared to quiescent superficial gastritis (12.5%) (p < 0.01), and the median and range were, respectively, 400 (0-1000) and 0 (0-200) pg/mg protein (p < 0.001). In patients with active superficial gastritis, a significant correlation between interleukin-6 and -8 was found (p 0.01). No difference was found regarding the mucosal levels of interleukin-1 beta according to the presence of H. pylori. CONCLUSIONS: These results suggest a possible pathogenetic role for interleukin-6 and interleukin-8 in H. pylori-associated gastritis.
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AIMS: To investigate the association between histologically confirmed gastritis, carriage of Helicobacter pylori and pepsinogen (PG) I and PG II concentrations. METHODS: Prospective study of 81 dyspeptic patients undergoing upper gastrointestinal endoscopy was made. The extent of gastric mucosal inflammation and the presence of H pylori was determined, and serology to evaluate PG I and II concentrations and IgG titres to H pylori was carried out. RESULTS: The presence of H pylori was strongly correlated with high IgG antibody titres to H pylori and gastritis. Patients who were H pylori positive had significantly higher PG I and PG II concentrations and a significantly lower PG I:PG II ratio than patients who were negative for H pylori. In 13 patients with duodenal ulcer and H pylori positive gastritis serum PG I concentrations were significantly higher than in H pylori positive patients without duodenal ulcer. Significant correlations were found between the age of patients and serum PG II, the PG I:PG II ratio, IgG antibodies to H pylori, the severity of body gastritis and H pylori infection, and between the degree of gastritis in the body of the stomach and the PG II concentration. CONCLUSIONS: Serum PG I and II concentrations, together with a fall in the PG I:PG II ratio, could be used as predictors of H pylori infection as well as serum IgG antibody response to H pylori.
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The importance of pro-inflammatory leukotriene C4 in Helicobacter pylori (H. pylori) associated gastritis in man is unknown. Fresh gastric biopsy specimens from 28 dyspeptic patients were obtained: 10 showed normal antral histology with no evidence of H. pylori, the remaining 18 patients exhibited histological gastritis and were H. pylori positive as assessed by histology, culture and urease test. Twelve of these 18 patients received 240 mg twice daily colloidal bismuth subcitrate for four weeks before re-endoscopy. Gastric biopsies from H. pylori positive patients were incubated under basal and Ca(2+)-ionophore mediated conditions: Radioimmunoassay analysis of the supernatant showed basal release of prostaglandin E2 and leukotriene C4 was slightly but not significantly elevated in H. pylori positive mucosa. However in H. pylori positive mucosa there was an 85% increase in leukotriene C4 synthesis when biopsies were incubated with ionophore, compared to only 13% increase in H. pylori negative mucosa (p less than 0.02). After eradication of H. pylori by colloidal bismuth subcitrate, there was a clearance of inflammatory cell infiltrate as assessed by histology and a significant reduction in ionophore-mediated leukotriene C4 formation compared with before treatment (p less than 0.02). These results suggest that H. pylori gastritis is associated with increased capacity to generate leukotriene C4, which may amplify the damaging effects of the bacteria on gastric mucosa.