900

among the higher social-economic groups. There is no ground forcomplacency--something that the Health Select Committee plainlyrealised, since they unanimously rejected the industry’s view thatadvertising does not influence consumption. Despite the clearevidence of the Smee report-severely criticised only by the tobaccoand advertising industries-the Government seems still to cling tothis "highly implausible argument". I quote Sir Michael Atiyah,president of the Royal Society, who criticised their refusal toendorse a ban as "utterly irresponsible". How regrettable that theydid not take the opportunity of their response to the SelectCommittee to announce a change of policy.Action on Smoking and Health,109 Gloucester Place,London W1 H 3PH, UK DAVID POLLOCK

1. Lader D, Matheson J. Smoking among secondary school children in 1990. London:HM Stationery Office, 1991.

Diabetes in the developing worldSIR,-Last year, Friends of Overseas Hospitals sent a short,

open-ended, questionnaire on diabetes to 300 randomly selectedrural district hospitals in the developing world. The questionnairewas designed to explore the possible prevalence of the disease, itspresentation and course, and any difficulties in management.

Replies were received from 105 hospitals in 32 countries, 21 fromsub-Saharan Africa. We analysed 100 of these replies. A newdiabetic patients was seen every month in 40 hospitals, and everythree months in 30, whereas 26 hospitals reported that they rarelysaw a case. Questions were asked about the incidence of common (inthe developed world) complications: blindness, foot infections, andgangrene. Of the 12 hospitals replying from Malawi only 1 had seenthe occasional blind diabetic, and from rural areas, foot infectionsand gangrene appeared equally rare. However, the 2 specialistcentres that replied did see many diabetics with retinopathy andcataracts, and these often presented with symptoms.

Although insulin was thought to be necessary in 20-50% of allpatients, availability and expense were major problems. None of the13 hospitals in Zambia that replied had a secure supply, but boughtinsulin from overseas. A Tanzanian presented the stark economicfacts: one vial of 100 U insulin cost Sh 1700, patients were chargedSh 250 (a month’s wages), and the hospital absorbed the deficit.There were also difficulties in keeping insulin, inconsistency inpotency, and a lack of correlation of strength with available syringes.There were three recorded deaths from hypoglycaemia, all of whichwere caused by overdoses administered by health professionals.Some hypoglycaemic episodes after discharge from hospital werethought to be due to differences in lifestyle between inpatients andrural workers. Tragically, deaths caused by running out of insulinwere reported in patients previously well-maintained.

This preliminary and incomplete investigation has resulted inmore questions than were asked, and we hope to follow these up.Only two firm conclusions can be reached: guidelines on whichpatients need treatment should be available to all health workers,and if insulin is needed, a secure supply is vital, perhaps on a"named patient" basis as reported from the Gambia.Friends of Overseas Hospitals,7 Akenside Road,London NW3 5RA, UK ANNE SAVAGE

Detection of Helicobacter pylori DNA byPCR in gastrointestinal equipment

SIR,- The polymerase chain reaction (PCR) has been usedsuccessfully for the diagnosis of gastric infections by Helicobacterpylori, and was more sensitive than culture and other routinelaboratory tests.1-5 That gastric biopsy specimens were positive forH pylori by PCR but negative by culture and histologyl raises thequestion whether fibreoptic endoscopes could retain bacterialDNA. We therefore tested endoscopes for the presence of

amplifiable H pylori DNA after cleaning and disinfection accordingto an all-channel procedure with 2 % glutaraldehyde.

Five endoscopes were flushed on 23 occasions divided betweentwo endoscopy programmes with about 05 ml water, of which

10 µL was tested in the PCR with primers directed at the 16S RNAgene.4 Definite results were obtained after Southern blot analysis ofPCR products with a 32P-labelled internal oligoprobe. In 8 of 23instances the PCR appeared to be positive. In 5 of these cases thebiopsy specimen taken during the previous endoscopical procedureby the same endoscope was H pylori positive either by culture orPCR. In 1 case the preceding gastric tissue sample was negative.However, the same endsocope proved to be H pylori positive byPCR on the previous check. For the remaining 2 occasions no resultfrom a preceding biopsy specimen was available. Of the 15 flushingfluids that were PCR negative for H pylori, 8 were preceded by anH pylori negative biopsy specimen. On 7 occasions no culture orPCR result from a preceding biopsy specimen was available.

Positive PCR results due to sample contamination in the

laboratory are highly unlikely since negative controls showed nodetectable signal after amplification. To validate our procedure weadditionally tested 10 strongly positive gastric biopsy specimens and10 PCR buffer solutions in the H pylori PCR according to ourstandard procedure in a blinded way. This experiment was repeatedtwice. After breaking, the code all results were correct.Thus, we showed that H pylori DNA could be detected by PCR

in gastrointestinal fibreoptic equipment that had been cleaned anddisinfected according to current standards. Before PCR can befurther assessed for the detection of H pylori DNA in gastric tissue,cleaning and disinfection methods have to be evaluated for theeradication of H pylori DNA from gastrointestinal equipment.

Departments of Clinical Microbiology,Gastroenterology and Pathology,

Free University Hospital,1081 HV Amsterdam, Netherlands

ROBERT ROOSENDAALERNST J. KUIPERSADRIAAN J. C. VAN DEN BRULEA. SALVADOR PEÑASTEFAN G. M. MEUWISSEN

JAN M. M. WALBOOMERSJOHANNES DE GRAAFF

1. Clayton CL, Kleanthous H, Coates PJ, Morgan DD, Tabaqchali S. Sensitive

detection of Helicobacter pylori by using polymerase chain reaction. J Clin Microbiol1992; 30: 192-200.

2. Engstrand L, Nguyen A-MH, Graham DY, El-Zaatari FAK. Reverse transcriptionand polymease chain reaction amplification of rRNA for detection of Helicobcterspecies. J Clin Microbiol 1992; 30: 2295-301.

3. Hammar M, Tyszkiewicz T, Wadström T, O’Toole PW. Rapid detection ofHelicobacter pylori in gastric biopsy material by polymerase chain reaction. J ClinMicrobiol 1992; 30: 54-58.

4. Ho S-A, Hoyle JA, Lewis FA, et al. Direct polymerase chain reaction test for detectionof Helicobacter pylori in humans and animals. J Clin Microbiol 1991; 29: 2543-49.

5. Hoshina S, Kahn SM, Jiang W, et al. Direct detection and amplification ofHelicobacter pylori ribosomal 16S gene segments from gastric endoscopic biopsies.Diagn Microbiol Infect Dis 1990; 13: 473-79.

Helicobacter pylori: host responses in pepticulceration

SIR,-In your Jan 30 commentary, Professor Lee concludes thatthere are no ulcerogenic strains of Helicobacter pylori and suggeststhat the research priority should be to examine host responses.Although we concur that host factors have a pivotal role in thegenesis of gastric and duodenal ulcers, we do not agree with theconclusion that there are no ulcerogenic strains of H pylori. Webelieve that there is increasing evidence from molecular biology andimmunology for the division of H pylori strains into at least twomajor groups-one producing the 128 kDa antigen and thevacuolating cytotoxin and another that does not produce theseantigens. Evidence from our laboratory shows that despite the highgenomic variability of different H pylori isolates, the two groups canbe differentiated genetically. 1

Examination of the antibody responses of patients with duodenalulceration has shown a significant association between ulcerationand mucosal 19A2 and systemic IgG3,4 recognition of a 120-130 kDaprotein of H pylori. We have developed a specific enzyme-linkedimmunosorbent assay based on a purified recombinant fragment ofthe 128 kDa antigen, which has allowed quantitative assessment ofserological responses to this protein in patients with differentgastroduodenal pathology. Examination of serum samples of 82dyspeptic patients (mean age 50-6 [SD 13 4] years) undergoingendoscopy showed that patients with duodenal ulcers (n = 20) havesignificantly higher systemic IgG responses to the antigen than do