Gastroesophageal reflux disease is a common cause of noncardiac chest pain in a country with a low prevalence of reflux esophagitis

Gastroesophageal reflux disease is believed to be uncommon in the East. This study aimed to determine if such a condition was a significant cause of noncardiac chest pain in Singapore. Eighty consecutive patients with recurrent chest pain, who had cardiac and other obvious causes excluded, underwent esophagogastroduodenoscopy, standard manometry, acid perfusion test, and prolonged ambulatory pH and pressure monitoring. Endoscopic esophagitis, positive acid perfusion tests, pathologic reflux, and positive chest pain-reflux correlation were detected in 7/80 (8.8%), 11/70 (15.7%), 14/61 (23.0%), and 12/25 (48.0%) patients, respectively. Among those with pathologic reflux, endoscopic esophagitis was present in only two (14.3%). Overall, 32 (40%) patients had gastroesophageal reflux disease. Esophageal motility disorder, alone or in association with gastroesophageal reflux disease, was demonstrated in only five (6.3%) patients. Our results confirmed western reports that gastroesophageal reflux disease was a common cause of noncardiac chest pain, whereas motility disorder was an infrequent cause of such pain.

Suppression of mouse skin tumor promotion and induction of apoptosis in HL-60 cells by Alpinia oxyphylla Miquel (Zingiberaceae)

There have been considerable efforts to search for naturally occurring substances for the intervention of carcinogenesis. Many components from dietary or medicinal plants have been identified that possess substantial chemopreventive properties. An example is curcumin (Curcuma longa Linn., Zingiberaceae), which has been shown to inhibit tumor promotion in experimental carcinogenesis. Alpinia oxyphylla Miquel, another plant of the ginger family used in oriental herbal medicine, contains diarylheptanoids whose structures are analogous to that of curcumin. In the present study, we have tested A.oxyphylla for its ability to suppress tumor promotion. Thus, topical application of the methanolic extract of dried fruits of A.oxyphylla significantly ameliorated 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin tumor promotion as well as ear edema in female ICR mice. In another study, treatment of HL-60 cells with the methanolic extract of A.oxyphylla significantly reduced the viability of the cells and also inhibited DNA synthesis. Microscopic examination of the treated cells showed characteristic morphology of apoptosis. Furthermore, cells treated with the extract of A.oxyphylla exhibited internucleosomal DNA fragmentation in time- and concentration-dependent manners. TPA-stimulated generation of superoxide anion in differentiated HL-60 cells was also blunted by A.oxyphylla. Taken together, these findings suggest that A.oxyphylla possesses potential chemopreventive and antitumorigenic activities.

Validation of [13C]urea breath test for Helicobacter pylori using a simple gas chromatograph-mass selective detector

OBJECTIVE

Isotope ratio mass spectrometry (IRMS) is the accepted method for accurately measuring the 13CO2:12CO2 ratio in the non-invasive and non-radioactive [13C]urea breath test (13C-UBT) for Helicobactor pylori. The IRMS instrument, an expensive and highly specialized analyser, is rarely available. The objective of this project was to modify and validate the use of a simple bench-top gas chromatograph-mass selective detector (GC-MSD) for 13C-UBT.

METHODS

Breath samples from 71 patients were taken at baseline and 30 min after ingestion of 100 mg [13C]urea. The breath samples were analysed using GC-MSD in the selected ion monitoring mode. The reference 13CO2:12CO2 ratio was from NBS19 obtained from the US National Institute of Standards and Technology. 13CO2:12CO2 ratios of the breath samples were determined. Excess delta per thousand (per mil, delta/thousand) of the 30 min sample over the baseline (deltadelta/thousand) of > or = 6deltadelta/thousand was considered H. pylori positive. Results from 13C-UBT and histology determined blind to each other were compared.

RESULTS

The coefficient of variation of the reference 13CO2:12CO2 ratio was 0.06%. Using histology as the 'gold standard', the sensitivity (97.9%) and specificity (95.8%) of the GC-MSD 13C-UBT were comparable to those of other methods of H. pylori diagnosis.

CONCLUSION

A gas chromatograph coupled to a mass selective detector that is available in many analytical and biomedical laboratories can be used for the 13C-UBT. This method will increase the availability and reduce the cost of this non-invasive, non-radioactive diagnostic test.

Non-cardiac, non-oesophageal chest pain: the relevance of psychological factors

BACKGROUND

No cause has been determined for chest pain that is neither cardiac nor oesophageal in origin.

AIMS

To compare the prevalence of life-time psychiatric disorders and current psychological distress in three consecutive series of patients with chronic chest or abdominal pain.

PATIENTS

Thirty nine patients with non-cardiac chest pain and no abnormality on oesophagogastroduodenoscopy, oesophageal manometry, and 24 hour pH monitoring; 22 patients with non-cardiac chest pain having endoscopic abnormality, oesophageal dysmotility, and/or pathological reflux; and 36 patients with biliary colic.

METHODS

The Diagnostic Interview Schedule and the 28 item General Health Questionnaire were administered to all patients.

RESULTS

Patients with non-cardiac chest pain and no upper gastrointestinal disease had a higher proportion of panic disorder (15%), obsessive-compulsive disorder (21%), and major depressive episodes (28%) than patients with gallstone disease (0%, p < 0.02; 3%, p < 0.02; and 8%, p < 0.05, respectively). In contrast, there were no differences between patients with non-cardiac chest pain and upper gastrointestinal disease and patients with gallstone disease in any of the DSM-111 defined lifetime psychiatric diagnoses. Using the General Health Questionnaire, 49% of patients with non-cardiac chest pain without upper gastrointestinal disease scored above the cut off point (that is, more than 4), which was considered indicative of non-psychotic psychiatric disturbance, whereas only 14% of patients with gallstones did so (p < 0.005). The proportions of such cases were however similar between patients with non-cardiac chest pain and upper gastrointestinal disease (27%) and patients with gallstones.

CONCLUSIONS

Psychological factors may play a role in the pathogenesis of chest pain that is neither cardiac nor oesophagogastric in origin.

Prolonged ambulatory oesophageal pH and pressure recording in healthy adults in Singapore

BACKGROUND/AIM OF STUDY

Data on prolonged ambulatory oesophageal pH and pressure monitoring in normal subjects in the East are limited. This study aimed to define the normal characteristics of ambulatory oesophageal pH and motility among healthy adults in Singapore.

METHOD

Prolonged ambulatory oesophageal pH and pressure recording was performed on 10 healthy volunteers using a one-channel pH probe, a two channel pressure probe, a portable digital data recorder and a computerised data analysis system. The median (range) number of episodes with pH < 4 and the percentage of total time with pH < 4 were 24% (4%-56%) and 3.0% (0.2%-4.0%) respectively. They were greater in the upright than supine positions.

RESULTS

The median percentages of peristaltic and simultaneous contractions were 65.8%-80.5% and 10.6%-12.7% respectively. The frequency, amplitude and duration of peristaltic contractions were greater during mealtimes than between meals in the upright position.

CONCLUSION

This study provides the first data on prolonged ambulatory oesophageal pH and manometry in healthy Singaporean adults.

Calcitonin gene-related peptide protects cultured rat gastric mucosal cells

Capsaicin exerts its gastroprotective effect by stimulating primary afferent neurons, releasing calcitonin gene-related peptide (CGRP), which in turn increases gastric blood flow. In this work, the effects of capsaicin, rat alpha-CGRP, and relative peptides hCGRP(8-37) and beta-hCGRP, and substance P on cultured gastric mucosal cells independent of neural and vascular mechanisms were studied. Damage was produced by indomethacin, ethanol or taurocholate 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and trypan blue exclusion tests were used to assess viability of the cultured cells. Capsaicin administration alone did not injure gastric cells. However, capsaicin pretreatment potentiated the damaging effect of indomethacin and ethanol. In the sodium taurocholate model, capsaicin slightly protected the cells against injury. Alpha-rCGRP was protective against indomethacin, ethanol and taurocholate in a dose-dependent manner. hCGRP(8-37) and beta-hCGRP both dose-dependently prevented injury caused by indomethacin at concentrations about eight times higher than that of alpha-rCGRP, but substance P was ineffective in the three different damage models. A combination of alpha-CGRP and hCGRP(8-37) was also protective against indomethacin damage to a similar extent as use of either agent alone. The defence mechanism of capsaicin against gastric cell injury may in part be mediated by a direct effect of CGRP on gastric mucosal cells, in addition to effects dependent on neural and vascular mechanisms. hCGRP(8-37) has no antagonist effect against CGRP in this model, suggesting that CGRP receptors in this model may be different from those in other tissues.

Role of capsaicin sensitive nerves in epidermal growth factor effects on gastric mucosal injury and blood flow

BACKGROUND

Epidermal growth factor (EGF) and capsaicin protect against experimental gastric mucosal injury. Capsaicin exerts its gastroprotective effect by stimulating afferent neurones leading to release of calcitonin gene related peptide (CGRP) which causes gastric hyperaemia. EGF also causes gastric hyperaemia but whether it acts via capsaicin sensitive neurones is unknown.

AIMS

To assess the influence of: (1) capsaicin desensitisation on EGF effects on gastric mucosal injury and gastric mucosal blood flow: and (2) close arterial infusion of hCGRP8-379, a CGRP antagonist, on EGF effects on gastric mucosal blood flow.

METHODS

The absolute ethanol induced gastric mucosal injury model in the rat was used. Gastric mucosal damage was assessed by planimetry and light microscopy. Gastric mucosal blood flow was measured by laser Doppler flowmetry in a gastric chamber preparation.

RESULTS

Capsaicin desensitisation abolished the gastroprotective and gastric hyperaemic effects of EGF. Close arterial infusion of hCGRP8-37 antagonised the hyperaemic effect of both capsaicin and EGF.

CONCLUSION

Results show that EGF may exert its gastroprotective and gastric hyperaemic effects via capsaicin sensitive afferent neurones.

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Tropical liver abscess

Forty-one consecutive cases of liver abscesses seen at the National University Hospital, Singapore from 1988 to 1994 were reviewed. Twenty-seven cases (65%) were pyogenic, six (15%) amoebic, two (5%) tuberculous and six (15%) indeterminate. The predominance of pyogenic abscesses is in marked contrast to previous studies from the region a decade ago in which amoebic abscesses were the commonest type. The commonest pathogen causing pyogenic abscess was Klebsiella pneumoniae. Two cases were due to Mycobacterium tuberculosis, and this organism needs to be actively looked for in smears and cultures of aspirated material. As the majority of organisms isolated were resistant to ampicillin, empirical antibiotic treatment for suspected pyogenic abscess should include gentamicin or a cephalosporin. Percutaneous needle aspiration of the abscess was performed for 85% of pyogenic abscesses and surgery was necessary in only two cases because of complications. We found that percutaneous aspiration of liver abscess is helpful to confirm the diagnosis, provides a better bacteriological culture yield, gives a good outcome, and may uncover clinically unsuspected conditions like malignancy and tuberculoma which may mimic the presentation of liver abscesses. We recommend routine cytological examination of aspirated abscess material as well as stains and cultures for acid-fast bacilli.

Effect of cisapride on functional dyspepsia in patients with and without histological gastritis: a double-blind placebo-controlled trial

In the present double-blind placebo-controlled study the effect of cisapride on functional dyspepsia was evaluated in patients with and without histological gastritis. Patients with functional dyspepsia and whose symptoms persisted after a 2 week run-in period with antacid treatment were randomized to receive cisapride (10 mg) or matching placebo three times daily for 4 weeks. Symptoms of epigastric pain, bloating, nausea, belching, early satiety and heartburn were graded on a four-point scale based on patients' feedback and diary card recording. A global response was also formulated by the investigators. One hundred and four patients entered the study and 76 completed the trial, comprising 36 patients with histological gastritis and 40 patients without gastritis. Symptom scores in both gastritis and non-gastritis groups were significantly improved by both cisapride and placebo; however, the improvement was not statistically different between the two treatment groups. Cisapride produced a good or better global response in 58% of subjects with histological gastritis and in 53% of subjects without gastritis compared with 47% and 52%, respectively, of patients on placebo; this difference was not statistically significant. Gastric histology did not influence the effect of cisapride on the symptoms of functional dyspepsia.

Subcutaneously administered recombinant human beta-interferon in the treatment of chronic hepatitis B virus infection

BACKGROUND

Treatment of chronic replicative hepatitis B virus (HBV) infection is aimed at stopping viral replication and preventing the development of chronic liver disease. beta-Interferon treatment has been less well studied than alpha-interferon.

METHODS

The efficacy and tolerability of a 6-month course of subcutaneously administered human recombinant beta-interferon (rINF-beta ser) was studied and the results of a low-dose regime compared with a high-dose regime. Twenty patients (17 men and three women), aged 24-54 years, with chronic hepatitis B virus infection (all hepatitis B surface antigen-positive with detectable HBV-DNA in their sera for at least 3 months prior to therapy) were randomized into two treatment groups of 10 patients each. The low-dose group received 6 x 10(6) U/dose and the high-dose group received 30 x 10(6) U/dose, both groups receiving their respective doses three times a week initially for 1 month and continuing for a total of 6 months.

RESULTS

The treatment was well tolerated in both groups. None of the patients required dosage reduction or cessation of treatment because of side-effects. HBV-DNA decreased in all patients during treatment, demonstrating the anti-viral efficacy of rINF-beta ser, and was undetectable in 20 and 40% of patients receiving low-dose and high-dose regimes, respectively, at the end of 6 months treatment (P = N.S.). One year after completion of treatment, HBV-DNA was undetectable in 50 and 30% of patients in the low-dose and high-dose groups, respectively (P = N.S.). However, only one patient achieved seroconversion with loss of the hepatitis B surface antigen and appearance of an antihepatitis B 'e' antigen at the end of 18 months.

CONCLUSION

This study shows that subcutaneously administered rINF-beta ser is well tolerated, but the optimal dose and duration of treatment still needs to be defined by further studies.

Endoscopic banding ligation treatment for bleeding oesophageal varices

Endoscopic variceal ligation (EVL) is a promising new method for controlling actively bleeding oesophageal varices as well as for their eradication. Compared to conventional endoscopic injection sclerotherapy, EVL has a lower rebleeding rate, fewer complications and can achieve faster variceal obliteration. Disadvantages of EVL include overtube trauma and possibly longer procedure time. However, recent development of newer devices such as the multiple banding ligator may overcome these shortcomings and improve results.

Working party report of the Gastroenterological Society of Singapore. Part II--Helicobacter pylori and non-ulcer dyspepsia in Singapore

Non-ulcer dyspepsia (NUD) is a common symptom whose cause is currently unclear. Helicobacter pylori (H pylori) infection is found in half of all patients with NUD but other pathophysiological abnormalities eg delayed gastric emptying, have also been described. NUD patients with or without H pylori infection have identical symptom patterns and pathophysiological parameters. Studies on the efficacy of H pylori treatment in NUD give equivocal results to date. We therefore do not recommend treatment for H pylori in NUD.

Effect of capsaicin and cimetidine on the healing of acetic acid induced gastric ulceration in the rat

BACKGROUND

Capsaicin protects the gastric mucosa against experimental injury while capsaicin desensitisation reduces the rate of gastric ulcer healing. The effect of exogenous capsaicin on gastric ulcer healing has not to date been reported.

AIM/METHOD

To investigate the effect of capsaicin, cimetidine, and in combination, given intragastrically in the healing of acetic acid induced chronic gastric ulcer in the rat. Treatment started immediately after ulcer induction.

RESULTS

At the end of one week, capsaicin, cimetidine, and in combination increased ulcer healing but the effect of combined treatment was less than that of capsaicin alone. In an in vivo gastric chamber preparation, capsaicin increased, while cimetidine decreased, gastric mucosal blood flow measured by laser Doppler flowmetry. A dose response effect in reduction of gastric mucosal blood flow could be demonstrated for cimetidine. The gastric hyperaemic effect of capsaicin was blunted by prior administration of cimetidine. In contrast, capsaicin had no effect on gastric acid secretion and its addition to cimetidine did not affect the acid suppressant effect of the latter.

CONCLUSIONS

Capsaicin promotes the healing of acetic acid induced gastric ulcer, probably by its gastric hyperaemic effect. Although cimetidine also promotes ulcer healing due to its inhibitory effect on acid secretion it may have an antagonistic effect on the gastric ulcer healing effect of capsaicin by virtue of inhibition of gastric hyperaemia.

Chronic upper abdominal pain due to duodenal ulcer and other structural and functional causes: its localization and nocturnal occurrence

The aim of the present study was to determine the degree of pain localization and frequency of nocturnal pain in duodenal ulcer and other causes of chronic upper abdominal pain. These parameters were prospectively recorded in a consecutive series of 1615 patients with chronic upper abdominal pain presenting to one gastroenterologist. The proportion of patients who were able to localize the site of their pain using a single finger was 13% for duodenal ulcer, 5% for gastric ulcer, 17% for biliary disease, 7% for functional dyspepsia and 8% for irritable bowel syndrome. The numbers of subjects with the above diagnoses who experienced nocturnal pain were 63, 63, 51, 41 and 58%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for duodenal ulcer were 13, 92, 14 and 91%, respectively, for localized pain; 63, 50, 11 and 93%, respectively, for nocturnal pain occurrence; and 9, 96, 20 and 90%, respectively, if the pain was both localized and nocturnal. If the pain was neither localized nor nocturnal, the corresponding values for the absence of duodenal ulcer disease were 49, 68, 93 and 13%, respectively. The pain of duodenal ulcer was therefore more likely to be nocturnal and well localized compared with pain from other causes. However, while the absence of these features made duodenal ulcer unlikely, their presence was less helpful in the diagnostic process.

Working Party report of the Gastroenterological Society of Singapore. Part I--Helicobacter pylori and peptic ulcer disease in Singapore

The Gastroenterological Society Working Party on Helicobacter pylori (H pylori) recommends eradication of H pylori in patients with peptic ulcer, provided H pylori infection has been demonstrated. H pylori treatment is not indicated for non-ulcer dyspepsia, histological gastritis or mere demonstration of H pylori infection. H pylori infection can be demonstrated by a urease test, culture or histological assessment on gastric antral biopsy or by a 13C and 14C urea breath test: serology is acceptable if validated in the local population. There are many eradication regimens for H pylori infection and follow-up assessments to demonstrate eradication is desirable.

Serological profiles of hepatitis B carrier patients in Singapore with special reference to the frequency and significance of concurrent presence of HBsAg and anti-HBs

Hepatitis B serological markers were investigated in 1,132 consecutive Singaporean HBV carriers. Hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) were found concurrently in 234 carriers (234/1132 or 21%). Serum anti-HBs levels were more than 10 mIU/mL in 80 of these carriers (80/234 or 34%). There were no difference in HBeAg positive status, as well as HBV-DNA positive status in concurrent HBsAg/anti-HBs carriers compared to carriers without anti-HBs. Our results suggested that concurrent HBsAg and anti-HBs is a common serologic pattern in Singaporean HBV carriers.

Primary biliary cirrhosis--an uncommon disease in Singapore

Primary biliary cirrhosis (PBC) is uncommon in Singapore. Twelve consecutive patients with PBC were seen between 1987 and 1994 at the National University Hospital. Eleven were women and the mean age at presentation was 53 years. Three patients presented with pruritus and jaundice whilst three had decompensated cirrhosis. The remaining six patients had no symptoms attributed to their liver disease when first detected, three of them presented with associated conditions including sicca syndrome and interstitial lung fibrosis, lichen planus, and carcinoma of breast. All patients had elevated serum alkaline phosphatase and positive anti-mitochondrial antibodies. Liver histology (10/12) showed Stage II disease (2), Stage III (5) and Stage IV (3). Three patients also had co-existing gall bladder stones but their endoscopic retrograde cholangiograms were normal. The mean follow-up period was 32.6 months and four patients died during follow-up. The only male patient had liver transplantation, two patients had symptomatic treatment while the rest were treated with ursodeoxycholic acid. In conclusion, local patients tended to presented relatively early in the course of the disease with 50% being asymptomatic and in the precirrhotic Stages.

The effect of polyunsaturated phosphatidyl choline in the treatment of acute viral hepatitis

BACKGROUND

Polyunsaturated phosphatidyl choline is a preparation often advocated for diseases of the liver.

METHODS

In a randomized open controlled trial, a preparation of polyunsaturated phosphatidyl choline, at a dose of 900 mg orally daily, was given to 22 patients with acute viral hepatitis. A control group of 25 patients was not treated.

RESULTS

Serial serum bilirubin and alanine amino transferase levels were measured up to 12 weeks. The falls in their levels after 2 and 5 weeks, and the lengths of time to their normalization, were not significantly different in the treated group compared to the control group.

CONCLUSION

The results indicated that polyunsaturated phosphatidyl choline had no beneficial effect on the course of acute viral hepatitis.

Treatment of hepatitis B surface antigen carriers in the early stage of the infection using recombinant alpha-interferon with steroid priming

BACKGROUND

Alpha-interferon has been found to inhibit hepatitis B virus (HBV) replication in Chinese patients with chronic HBV infection although a sustained effect was rarely achieved in those with normal pretreatment serum alanine amino transferase (ALT) levels. Prednisolone priming has been found to be beneficial over treatment with interferon alone in these subjects. We studied the effect of steroid pre-treatment followed by recombinant interferon alpha-2a in the treatment of asymptomatic HBV carriers with positive hepatitis Be antigen (HBeAg), hepatitis B viral DNA (HBV-DNA) and minimal changes in liver histology.

METHODS

The treatment regimen included a 6-week prednisolone priming, a 2 week rest followed by 14 weeks of three times weekly 9 mega units of interferon alpha-2a injection and 52 weeks of follow-up. There were seven patients in the treatment group and seven controls.

RESULTS

The mean age, pre-treatment ALT (normal in all except for one in each of the treatment and control groups), HBV-DNA levels and histological scores were similar in the two groups. Serum HBV-DNA levels fell in six patients during treatment and became undetectable in two of them by the end. During follow-up, serum HBV-DNA returned to pre-treatment levels in all patients. None of the treated patients had HBeAg sero-conversion and none of the controls had spontaneous clearance of HBV-DNA or sero-conversion of HBeAg. No improvement of liver histology was observed in any of the treated patients. There were only mild flu-like side-effects noted and interferon alpha-2a was well tolerated at the doses given among treated patients.

CONCLUSION

Prednisolone priming followed by interferon alpha-2a treatment has no beneficial effect on HBV carriers in the early stages of chronic hepatitis B infection.

How does chili cause upper gastrointestinal symptoms? A correlation study with esophageal mucosal sensitivity and esophageal motility

Chili ingestion produces gastrointestinal symptoms in many subjects. Some of these symptoms, such as heartburn, might well arise from the esophagus, but the pathogenesis is unknown. We studied the effects of chili ingestion on esophageal motility in 16 healthy volunteers and correlated these with the production of chili-induced upper gastrointestinal symptoms. We also studied the effects of chili instillation into the esophagus in 15 of the subjects to determine whether typical symptoms were produced. There were no changes in esophageal manometric parameters in all 16 subjects after the ingestion of a chili suspension (5 g chili powder in 100 ml water), although half of them reported one or more symptoms. Direct instillation of the same chili suspension into the lower esophagus produced typical symptoms in all 15 volunteers tested. Chili-induced upper gastrointestinal symptoms were not accompanied by changes in esophageal motility. The esophageal mucosa itself was sensitive to chili, suggesting that at least some of the upper gastrointestinal symptoms produced by chili are mediated by direct stimulation of chili-sensitive afferent nerve endings in the esophageal mucosa.

Roxatidine versus ranitidine in the treatment of duodenal ulcers: a randomized double-blind controlled multicentre study in Singapore

Roxatidine acetate, a new H2 receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25-33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P = NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P = NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine.

Immunogenicity and safety of an inactivated hepatitis A vaccine amongst Singaporeans

The immunogenicity and reactogenicity of an inactivated hepatitis A virus (HAV) vaccine was studied in healthy Singaporean adult volunteers. One hundred and forty healthy volunteers with normal alanine (ALT) and aspartate (AST) transaminases and no previous exposure to HAV, received three 1 ml doses (720 ELISA units) of an inactivated HAV vaccine (Smithkline Beechams Biologicals) following a 0, 1, 6 months vaccination schedule. All subjects were asked to record and grade the severity of any reactions for three consecutive days after each dose. Serum ALT and AST as well as anti-HAV were measured at 0, 1, 2, 6 and 7 months after the first vaccine dose. Anti-HAV seroconversion occurred when levels rose above 40 mIU/ml. Eighty-five percent of vaccinees seroconverted after the first innoculation and 99% after the second injection. All vaccinees seroconverted after the third dose. Geometric mean anti-HAV titers (GMTs) were, respectively, 119, 391, 4406 mIU/ml one month after each of the three doses. The most common side effect was transient pain and tenderness at the vaccination site. No elevation of ALT or AST levels were noted during the study period. The inactivated hepatitis A vaccine used in this study is safe and highly immunogenic in the local adult population. Two doses one month apart appeared to give adequate protection.