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Biomedical subjects

J Bickley

Publications and source records attributed to J Bickley.

18 recordsLinked to original sources
PubMed1992

DNA patterns of Helicobacter pylori isolated from gastric antrum, body, and duodenum.

Biopsy specimens for culture of Helicobacter pylori were obtained from two different sites in the antrum, gastric body, and duodenal cap in 20 patients during endoscopic investigation of dyspepsia. H. pylori was identified in 64 isolates obtained from 15 of the 20 patients. Analysis of chromosomal DNA from these isolates of H. pylori showed that 13 of 15 patients harbored a single strain of H. pylori throughout their stomach and duodenum. Two differing H. pylori types were found in two patients. Unique DNA patterns were shown in each of the 15 patients. The genetic heterogeneity of H. pylori is unexplained but it could be of considerable value for epidemiological studies.

Biopsy↗
PubMed1992

Ribosomal RNA gene patterns of Helicobacter pylori from surgical patients with healed and recurrent peptic ulcers.

Fifty-two strains of Helicobacter pylori were examined by DNA restriction endonuclease digestion, ribosomal (r)RNA gene probe hybridization and biotyping. Most (49) strains originated from gastric (antral) biopsies of patients before or after elective surgery for duodenal ulcers. Chromosomal DNA Hind III ribopatterns showed 9 strain clusters of which the largest contained 12 strains each with 3 common bands (1.50, 3.45, and 4.26 kb) but which were heterogeneous with respect to biotype and total digest pattern. Isolates from post-operative patients with either healed or recurrent ulcers showed ribopattern heterogeneity and exhibited a similar distribution of H. pylori ribopattern types; no single type predominated in any patient group or was more highly associated with recurrent ulcers than with healed ulcers. Multiple isolates from two surgical patients had only minor genomic variations in each set whereas isolates from two brothers had different ribopatterns. We conclude that Hind III ribopatterns in conjunction with total digest patterns might provide the basis for future epidemiological typing studies.

Adult↗
PubMed1992

Evidence of clonal variants of Helicobacter pylori in three generations of a duodenal ulcer disease family.

Nine members of a family with a high incidence of duodenal ulcer disease were studied by interview, examination of hospital records, endoscopy, and antral biopsy. Helicobacter pylori was confirmed by CLO test, histology and culture. DNA extraction from pure isolates of H pylori was possible in six family members and strain typing was performed by restriction fragment length polymorphism. DNA restriction digestion was followed by vacublotting and then DNA hybridisation, using a cDNA probe complimentary to H pylori rRNA cistrons. Eight of the nine family members were H pylori positive by CLO test and histology. Five had duodenal ulcer disease. Three family members (one from each generation) harboured clonal variants of a single parent strain of H pylori but only two had duodenal disease. The other three members harboured different strains. Intrafamilial clustering of clonal variants of H pylori occurs in some duodenal ulcer disease families. Family members however, may develop duodenal disease irrespective of the colonising strain.

Adolescent↗
PubMed1992

DNA fingerprints of Helicobacter pylori before and after treatment with omeprazole.

AIMS: To test whether a hypoacidic environment may potentially "stress" Helicobacter pylori DNA, encouraging the emergence of strain variation. METHODS: This hypothesis was tested by inducing prolonged hypoacidity with omeprazole, a potent antisecretory drug. The genomic DNA of H pylori was studied by electrophoretic separation of restriction endonuclease fragments followed by rRNA gene hybridisation in seven patients infected with H pylori before and after treatment with omeprazole 20-40 mg daily for six to eight weeks. DNA was isolated and purified using the guanidium thiocyanate reagent method. DNA samples were digested with Hae III, electrophoresed, vacublotted, and hybridised using a biotinylated cDNA probe prepared from 16S and 23S rRNA from H pylori NCTC 11638. Isolates were compared using their ribopatterns (DNA fingerprints). RESULTS: A total of 26 isolates were obtained; all DNA isolates were cut by Hae III, which was the enzyme that gave the best resolved hybridisation patterns for analysis. No two patients harboured the same strain. The isolates from two patients showed evidence of subtypic variation; one patient had two distinct strains and four patients had their own indistinguishable strains before and after treatment with omeprazole. For each patient, the paired ribopatterns of H pylori DNA were not affected by treatment with omeprazole for six to eight weeks. CONCLUSION: The H pylori genome is relatively stable when exposed to the conditions of prolonged hypoacidity that result from treatment with omeprazole.

DNA Fingerprinting↗
PubMed1992

Ribosomal RNA gene restriction patterns of Helicobacter pylori: analysis and appraisal of Hae III digests as a molecular typing system.

Ribosomal RNA gene restriction patterns (ribopatterns) of 162 strains of Helicobacter pylori from 93 patients were studied to assess their suitability for use as the basis of a molecular typing system. Computer-assisted numerical analysis of Hae III ribopatterns of 122 strains from 9 countries in 4 continents showed that almost every strain had a distinct and unique ribopattern and only strains from the same individual were genomically matched in all bands or with minor (1-2 band) differences. Hae III ribopatterns offered high typability and reproducibility but were too discriminatory for large-scale epidemiological typing purposes because no rational basis for grouping strains was evident. In contrast, composite band profiles based on 21 band loci within the Hae III ribopatterns, which were used to compare strain sets selected on toxigenicity and geographical origin, were more conserved. Minor differences between some strain sets in several band loci were detected but generally the composite profiles were a reproducible feature of H. pylori. We conclude that Hae III ribopatterns provide an excellent fingerprint for small-scale studies of genomic variation in defined populations, such as sequential patient isolates, but are too specific for general typing of H. pylori.

Blotting, Southern↗
PubMed1992

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Humans↗
PubMed1991

Biotype and macromolecular profiles of cytotoxin-producing strains of Helicobacter pylori from antral gastric mucosa.

Biotype, genome, protein and plasmid profile diversity amongst 40 epidemiologically unrelated strains of Helicobacter pylori was studied. Strains were API Zym biotypes II, III and IV but most (87%) were biotype II. Four subsets of strains were defined on a combination of motility (56% positive) and cytotoxin production (44% positive). A close association (P = 0.45) between these two features was observed for 69% of strains. Each strain of H. pylori had a unique DNA type defined by either HaeIII or HindIII total digest patterns and by ribopatterns, except for DNA of the rare strains not cut by these endonucleases. Strain diversity was confirmed by one-dimensional SDS-PAGE electrophoretic protein patterns. No consistent associations between cytotoxin activity and overall ribopattern or band subsets within a ribopattern were detected. Some strains (39%) contained a plasmid but the presence of plasmids was not consistently associated with either cytotoxin activity, biotype, motility or ribopattern. We conclude that the cytotoxin-producing strains of H. pylori were genomically as diverse as the non-cytotoxin producing strains.

Bacterial Proteins↗
PubMed1991

Molecular techniques for studying the epidemiology of infection by Helicobacter pylori.

The efficacy of one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell protein patterns for fingerprinting isolates of Helicobacter pylori was assessed by means of computerized numerical analysis. Virtually all strains were found to have unique, stable, and reproducible protein profiles. The application of this technique to a collection of isolates from eight patients showed clearly that each harboured a distinct strain that was present before treatment and persisted after treatment. This suggests that relapse was due to recrudescence of the same strain rather than re-infection with a different strain. Minor differences in protein banding profiles within sets of isolates from the same patient were evident, and this was confirmed by means of both two-dimensional PAGE protein patterns and restriction endonuclease analysis of DNA on the same strains.

DNA Fingerprinting↗
PubMed1991

Genomic variation in Helicobacter pylori: application to identification of strains.

DNA digest analysis, ribopatterns, and plasmid profiling were used to determine genomic variation in 55 strains of Helicobacter pylori from patients with gastritis in the USA, Peru, Australia, and the U.K. HaeIII-ribopatterns and total DNA digest patterns showed a high degree of heterogeneity, with at least 33 different genomic types among strains, including some sequential isolates. Plasmids, present in 51% of strains, were less useful as epidemiologic markers. Investigation of 14 multiple isolate sets showed that genotypic variants were present in pre- and post-treatment gastric mucosa, that relapse in some patients was due to reinfection by a genotypically different strain, and that the same strain persisted in most treatment failures. We conclude that molecular methods were excellent for precise identification of H. pylori, but ribopatterns had the advantages of reproducibility, high discrimination, and visual simplicity.

DNA Fingerprinting↗
PubMed1991

The kind of health service that nurses want.

What nurses see as an effective, efficient health service: In summary, an effective efficient health service in New Zealand will be based on: 1) Keeping what's good in our current service. 2) A nursing voice in decision-making about services. 3) Looking for successful models to follow. 4) The government having a major role. 5) Collective responsibility for funding. 6) Accountability and consultation. 7) Stability in industrial relations. 8) A strong, diverse nursing and midwifery service.

Health Policy↗