Displaying publications 81 - 100 of 333 in total

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  1. Goh KL, Chen Y, Chou SM, Listrat A, Bechet D, Wess TJ
    Animal, 2010 Sep;4(9):1613-7.
    PMID: 22444710 DOI: 10.1017/S1751731110000698
    The basic mechanism of reinforcement in tendons addresses the transfer of stress, generated by the deforming proteoglycan (PG)-rich matrix, to the collagen fibrils. Regulating this mechanism involves the interactions of PGs on the fibril with those in the surrounding matrix and between PGs on adjacent fibrils. This understanding is key to establishing new insights on the biomechanics of tendon in various research domains. However, the experimental designs in many studies often involved long sample preparation time. To minimise biological degradation the tendons are usually stored by freezing. Here, we have investigated the effects of commonly used frozen storage temperatures on the mechanical properties of tendons from the tail of a murine model (C57BL6 mouse). Fresh (unfrozen) and thawed samples, frozen at temperatures of -20°C and -80°C, respectively, were stretched to rupture. Freezing at -20°C revealed no effect on the maximum stress (σ), stiffness (E), the corresponding strain (ε) at σ and strain energy densities up to ε (u) and from ε until complete rupture (up). On the other hand, freezing at -80°C led to higher σ, E and u; ε and up were unaffected. The results implicate changes in the long-range order of radially packed collagen molecules in fibrils, resulting in fibril rupture at higher stresses, and changes to the composition of extrafibrillar matrix, resulting in an increase in the interaction energy between fibrils via collagen-bound PGs.
  2. Goh KL
    Med J Malaysia, 2009 Sep;64(3):187-92.
    PMID: 20527265
    Observations of racial differences in the prevalence of Helicobacter pylori in Malaysia have been intriguing. The Indians and Chinese consistently have a higher prevalence compared to the Malays. The racial cohort theory has been proposed to explain these differences where transmission and perpetuation of infection takes place within a racial group rather than between races, races being separate owing to the low rate of interracial marriages. Studies have demonstrated distinctive bacterial strains between races. Phylogenetic studies have shown that H. pylori isolates amongst Chinese and Indians are distinctive while Malays have Indian and other strains suggesting a more recent acquisition of the bacterium from Indians. H. pylori is recognized as the major causative factor in peptic ulcer disease and gastric cancer. Despite the high prevalence of H. pylori, Indians have a relatively low prevalence of peptic ulcer disease and a low incidence of gastric cancer. This paradox with regards to gastric cancer has been termed the "Indian enigma". Bacterial strain differences between races may be putative but this observation may also indicate gastroprotective environmental factors or a lower genetic susceptibility to develop cancer in the Indians.
  3. Goh KL
    J Gastroenterol Hepatol, 2011 Jan;26 Suppl 1:2-10.
    PMID: 21199509 DOI: 10.1111/j.1440-1746.2010.06534.x
    Gastroesophageal reflux disease (GERD), previously uncommon in Asia, has now become an important disease in the region. Although much variability exists between studies, most endoscopy-based studies show a prevalence of erosive esophagitis of more than 10%. Symptom-based studies also show a prevalence of 6-10%. Two longitudinal follow-up studies on GERD symptoms have shown an increase with time, and several endoscopy-based time trend studies have also shown a significant increase in erosive reflux esophagitis. Studies on Barrett's esophagus have been confounded by the description of short (SSBE) and long segment (LSBE) Barrett's esophagus. Great variation in prevalence rates has been reported. SSBE vary from 0.1% to more than 20% while LSBE vary from 1-2%. Of the putative causative factors, obesity has been the most important. Many studies have linked GERD-esophagitis as well as occurrence of reflux symptoms with an increase in body mass index (BMI), obesity, especially visceral or central obesity, and metabolic syndrome. A decline in Helicobacter pylori infection with growing affluence in Asia has been broadly thought to result in healthier stomachs and a higher gastric acid output resulting in reflux disease. However, variable results have been obtained from association and H. pylori eradication studies.
  4. Goh KL, Wong HT, Lim CH, Rosaida MS
    Aliment Pharmacol Ther, 2009 Apr 1;29(7):774-80.
    PMID: 19183160 DOI: 10.1111/j.1365-2036.2009.03930.x
    Dramatic changes in the prevalence and pattern of gastrointestinal disease has taken place in Asia in recent years.
  5. Goh KL
    J Dig Dis, 2007 Nov;8(4):179-85.
    PMID: 17970873
    The new millennium has seen distinct changes in the pattern of gastrointestinal disease in the Asia-Pacific region. These changes are important as more than half of the world's population come from the region and therefore impact significantly on the global disease burden. The highest incidence of gastric cancer (GCA) has been reported from Asia and GCA remains a very important cancer. However time-trend studies have shown a decrease in GCA incidence in several countries in Asia. A rise in cardio-esophageal cancers as seen in the West has not been reported. On the other hand, colorectal cancer has been steadily increasing in Asia with age-standardized incidence rates of some countries approaching that of the West. The pattern of acid-related diseases has also changed. Gastroesophageal reflux disease is a fast emerging disease with an increasing prevalence of reflux esophagitis and reflux symptoms. The prevalence of peptic ulcer disease has at the same time declined in step with a decrease in H. pylori infection. Many of the changes taking place mirror the Western experience of several decades ago. Astute observation of the epidemiology of emerging diseases combined with good scientific work will allow a clearer understanding of the key processes underlying these changes. With rapid modernization, lifestyle changes have been blamed for an increase in several diseases including gastroesophageal reflux disease, nonalcoholic fatty liver disease and colorectal cancer. A worrying trend has been the increase in obesity among Asians, which has been associated with an increase in metabolic diseases and various gastrointestinal cancers. Conversely, an improvement in living conditions has been closely linked to the decrease in GCA and H. pylori prevalence.
  6. Goh KL, Cheah PL, Navaratnam P, Chin SC, Xiao SD
    J Dig Dis, 2007 Aug;8(3):139-42.
    PMID: 17650225
    The gastric biopsy urease test is an accurate and robust diagnostic test for Helicobacter pylori infection. Large endoscopy units use their own homemade unbuffered ultra-rapid urease test for diagnosis of H. pylori infection but several commercial rapid urease tests are available.
  7. Goh KL
    J Gastroenterol Hepatol, 2004 Sep;19 Suppl 3:S22-5.
    PMID: 15324378
    Gastroesophageal reflux disease (GERD) is a common disease in the West, which now appears to be also increasing in prevalence in the Asian Pacific region. The reasons for this changing epidemiology are two-fold: an increased awareness among doctors and patients, and/or a true increase in the prevalence of the disease. Prevalence rates of reflux esophagitis (RE) of up to 16% and prevalence of GERD symptoms of up to 9% have been reported in the Asian population. However, the frequency of strictures and Barrett's esophagus remain very low. Non-erosive reflux disease (NERD) appears to be the most common form of GERD among Asian patients accounting for 50-70% of cases with GERD. Among Asian patients differences can also be discerned among different ethnic groups. For example, in Malaysia where a multiracial society exists, RE is significantly more common among Indians compared to Chinese and Malays whereas NERD is more frequently seen in the Indian and Malays compared to the Chinese. The reasons for these differences are not known but may indicate both genetic factors and environmental factors peculiar to the particular racial group. GERD has also been increasing in the region demonstrating a time-lag phenomenon compared to the West. Differing predisposition to GERD among different ethnic groups would mean that such an increase would be more prominent among certain racial groups.
  8. Goh KL, Quek KF, Yeo GT, Hilmi IN, Lee CK, Hasnida N, et al.
    Aliment Pharmacol Ther, 2005 Nov 1;22(9):859-64.
    PMID: 16225496
    Colorectal cancer is one of the most common forms of gastrointestinal cancer in the world today. In the Asia-Pacific area, it is the fastest emerging gastrointestinal cancer.
  9. Goh KL
    Med J Malaysia, 2005 Jul;60 Suppl B:94-8.
    PMID: 16108185
    Chronic pancreatitis is a difficult disease to treat. Worldwide, alcohol is the most common aetiology but based on recent studies it is clear that genetic susceptibility plays an important role in determining disease. Several important genetic mutations have been identified. The prevalence of chronic pancreatitis appears to be lower in Asia although very high rates have been reported in parts of India. Severe intractable pain is the predominant presenting complaint of patients. The natural history of the disease and the onset of exocrine and endocrine insufficiency depend on the classification of disease as early onset, late-onset or alcohol associated. Complications of chronic pancreatitis are important and include pseudocyst formation, bile duct and duodenal strictures.
  10. Goh KL, Mahendra Raj S, Parasakthi N, Kew ST, Kandasami P, Mazlam Z
    Med J Malaysia, 1998 Sep;53(3):302-10.
    PMID: 10968173
    The Working Party Report on the Management of Helicobacter pylori serves as a clinical practice guideline for Malaysian doctors. H. pylori is not uncommon in the Malaysian population. Marked racial differences and the consistently low prevalence rates amongst Malays are noted. The working party recommends that if endoscopy is to be performed, a rapid urease test should be used for diagnosis. Where suspicion of the infection is strong and the urease test is negative, histology should be performed on gastric biopsies. Culture should be used to monitor resistance patterns to antibiotics and regional laboratories should assume this responsibility. The urea breath tests are highly accurate tests for diagnosis of H. pylori but is as yet not widely available in Malaysia. The working party strongly recommends that all peptic ulcer patients infected with H. pylori whether active, in remission and complicated ulcers should be treated for the infection. Patients with low-grade gastric mucosal lymphoid tissue lymphoma should also be treated for H. pylori infection. It is considered advisable that patients on long term nonsteroidal antinflammatory drug (NSAID) treatment with a history of peptic ulcers or dyspepsia and patients following resection of early gastric cancer or those with a family history of gastric cancer should also be tested and treated for H. pylori. The working party recommends, as first line treatment a 7-day combination therapy of a proton pump inhibitor, clarithromycin and metronidazole or amoxicillin. High metronidazole resistance rates locally may adversely affect regimens containing the antibiotic. It should also be noted that regimens that yield lower eradication rates may result in higher long term expenditure.
  11. Goh KL, Chang CS, Fock KM, Ke M, Park HJ, Lam SK
    J Gastroenterol Hepatol, 2000 Mar;15(3):230-8.
    PMID: 10764021
    Gastro-oesophageal reflux disease (GORD) occurs more frequently in Europe and North America than in Asia but its prevalence is now increasing in many Asian countries. Many reasons have been given for the lower prevalence of GORD in Asia. Low dietary fat and genetically determined factors, such as body mass index and maximal acid output, may be important. Other dietary factors appear to be less relevant. Increased intake of carbonated drinks or aggravating medicines may influence the increasing rates of GORD in some Asian countries but no strong evidence links other factors, such as the age of the population, smoking or alcohol consumption, to GORD. The management of GORD in Asia is similar to that in Europe and North America but the lower incidence of severe oesophagitis in Asia may alter the approach slightly. Also, because Asians tend to develop stomach cancer at an earlier age, endoscopy is used routinely at an earlier stage of investigation. Gastro-oesophageal reflux disease is essentially a motility disorder, so short-term management of the disease can usually be achieved using prokinetic agents (or histamine (H2)-receptor antagonists). More severe and recurrent GORD may require proton pump inhibitors (PPI) or a combination of prokinetic agents and PPI. The choice of long-term treatment may be influenced by the relative costs of prokinetic agents and PPI.
  12. Goh KL
    J Gastroenterol Hepatol, 2002 Apr;17(4):482-7.
    PMID: 11982731
    Helicobacter pylori infection has many different clinical outcomes. Not all infected persons need to be treated. Therefore, indications for treatment have to be clear, and several consensus guidelines have been formulated to aid the medical practitioner in this decision-making process. Triple therapy with a proton pump inhibitor (PPI), in combination with amoxicillin and clarithromycin is the established treatment of choice. For patients with penicillin hypersensitivity, metronidazole can be substituted for amoxicillin. Bacterial resistance to antibiotics is a major factor adversely affecting treatment success. Resistance to metronidazole has been reported in up to 80%, and resistance to clarithromycin in 2-10% of strains cultured. Resistance to either one of the antibiotics has been reported to result in a drop in efficacy of up to 50%. Emergence of resistance to both metronidazole and clarithromycin following failed therapy is a cause for concern; this underlines the need to use the best available first-line therapy. To avoid the emergence of resistance to both key antibiotics, the combination of metronidazole and clarithromycin should be avoided where possible. For failed treatment, several strategies can be employed. These include ensuring better compliance with repeat therapy, and maximizing the efficacy of repeat treatment by increasing dosage and duration of treatment, as well as altering the choice of drugs. Quadruple therapy incorporating a bismuth compound with a PPI, tetracycline and metronidazole has been a popular choice as a "rescue" therapy. Ranitidine bismuth citrate has been shown to be able to overcome metronidazole and clarithromycin resistance; it may be a useful compound drug to use in place of a PPI in "rescue" therapies. In the case of persistent treatment failures, it is useful to consider repeating gastroscopy and obtaining tissue for culture, and then prescribe antibiotics according to bacterial susceptibility patterns. It is also important in refractory cases to review the original indication for treatment and determine the importance of the indication.
  13. Goh KL
    J Gastroenterol Hepatol, 1997 Jun;12(6):S29-35.
    PMID: 9195409
    The aim of the present study was to determine the risk factors for Helicobacter pylori in a dyspeptic Malaysian population. A cross-sectional survey of 1060 consecutive patients presenting with dyspepsia at the Endoscopic Unit, University Hospital, Kuala Lumpur, Malaysia from January 1994 to July 1995 was undertaken. All patients answered a detailed questionnaire and underwent endoscopy, with two antral biopsies taken for diagnosis of H. pylori using a rapid urease test. An overall H. pylori prevalence of 49.0% was recorded. Helicobacter pylori prevalence in relation to the major endoscopic diagnoses were as follows: non-ulcer dyspepsia (NUD) 31.2%; duodenal ulcer (DU) 91.4%; and gastric ulcer (GU) 74.1%. The prevalence among the races were as follows: Malay 16.4%; Chinese 48.5%; and Indians 61.8%. Multiple logistic regression analysis identified the following as independent risk factors: > 45 years old 1.5 (1.1,2.0); male gender 1.6 (1.2,2.1); ethnic group: Chinese 2.5 (1.7,3.7); Indians 4.9 (3.2,7.5); level of education: low 2.3 (1.5,3.5); middle 1.7 (1.1,2.6); and smoking 1.6 (1.2,2.3). Analysis was also performed on DU, GU and non-UD patients separately; in both DU and GU patients, H. pylori prevalence was high regardless of age, sex, race or level of education. However, in DU patients, Indian race had an independent risk factor (Odds ratio = 7.8 (1.2,48.4)). The findings in the NUD group reflected the findings in the ¿all patients' group; > 45 years old, male gender, Indian and Chinese race, and low level of education were also significant, independent risk factors. The overall differences in H. pylori prevalence between the different subgroups were mainly due to differences in the NUD group. The increased risk of H. pylori infection in Chinese and Indians points to either an inherent ethnic genetic predisposition or to socio-cultural practices peculiar to the particular race which may be responsible for transmission of the infection.
  14. Goh KL, Parasakthi N, Peh SC, Ong KK
    Med J Malaysia, 1995 Sep;50(3):208-11.
    PMID: 8926896
    Sixty-three breath samples were collected from patients who underwent a 14C-urea breath test. Following ingestion of a radiolabelled 14C-labelled urea solution, breath samples containing 14C-labelled carbon dioxide were trapped in a solution containing hyamine hydroxide. Samples were then counted in a liquid scintillation counter. Breath samples were collected at 2, 15, 20, 25 and 30 minutes following ingestion of the urea solution. The presence or absence of Helicobacter pylori (HP) infection was determined on the basis of endoscopic biopsy tests which included culture, histological examination, rapid urease test and a gram stain of a fresh tissue smear. Thirty-two HP positive and 31 HP negative samples were collected. The mean counts at 15, 20, 12 and 30 minutes time points were: 4413, 4458, 4109 and 3795 dpm respectively for the positive samples and 1275, 877, 690 and 565 dpm respectively for the negative samples. Based on a cutoff value (mean of the negative samples + 3 standard deviations) for every time point, HP positive and negative samples could be clearly differentiated giving a sensitivity and specificity of 100%. The 14C-urea breath test is a reliable and convenient diagnostic test for H. pylori.
  15. Goh KL, Parasakthi N, Chuah SY, Cheah PL, Lo YL, Chin SC
    Aliment Pharmacol Ther, 1997 Dec;11(6):1115-8.
    PMID: 9663838
    OBJECTIVES: To determine and compare the efficacy and tolerability of two 1-week regimen comprising omeprazole, clarithromycin and amoxycillin or metronidazole in the eradication of Helicobacter pylori, and to determine the influence of bacterial resistance to metronidazole and clarithromycin on the outcome of treatment.

    PATIENTS AND METHODS: Patients with unequivocal evidence of H. pylori infection based on culture, histology and rapid urease test of both antrum and corpus biopsies were recruited for the study. The study was a randomized, investigator-blind, comparative study. Patients received either omeprazole 20 mg o.m., clarithromycin 250 mg b.d. and amoxycillin 500 mg b.d. (OAC) or omeprazole 20 mg o.m., metronidazole 400 mg b.d. and clarithromycin 250 mg b.d. (OMC) for 1 week. Patients were assessed for successful eradication, which was defined as absence of bacteria in all tests (culture, histology and urease test on both antral and corpus biopsies), at least 4 weeks after completion of therapy.

    RESULTS: Eighty-two patients were recruited for the study. Eradication rates on intention-to-treat analysis were--OAC: 36/41 (87.8%, 95% CI: 73.8, 95.9); OMC: 33/41 (80.5%, 95% CI: 65.1, 91.2). On per protocol analysis were--OAC: 36/40 (90%, 95% CI: 76.3, 97.2); OMC: 32/38 (84.2%, 95% CI: 68.7, 94.0). All side-effects encountered were mild and no patient discontinued treatment because of intolerance to medications. The most common side-effects were altered taste (OAC 31.7%, OMC 53.7%) and lethargy (OAC 14.6%, OMC 19.5%). Pre-treatment metronidazole resistance was encountered in 34/63 (54.0%) patients. No bacterial strains were found with primary resistance to clarithromycin. Metronidazole resistance did not significantly affect eradication rates. Emergence of resistance to clarithromycin was not seen post-therapy.

    CONCLUSIONS: Both the OAC and the OMC regimens were convenient and well-tolerated treatments for H. pylori. However, eradication rates were lower than anticipated.

  16. Goh KL
    Med J Malaysia, 1997 Jun;52(2):161-8.
    PMID: 10968075
    The link between Helicobacter. pylori and peptic ulcer disease in 1997 is an irrefutable one. The association between infection and ulcerogenesis has been shown to be biologically plausible with induction of epithelial inflammation and cell damage and its effect on gastrin/acid homeostasis. The association of H. pylori infection and peptic ulcer disease is a close and consistent one. There is ample evidence indicating that H. pylori eradication results in virtual abolition of ulcer relapse. Several studies have demonstrated that eradication of H. pylori results in ulcer healing and there is evidence showing a temporal relationship between infection and development of peptic ulcer disease.
  17. Goh KL, Paramsothy M, Azian M, Parasakthi N, Peh SC, Bux S, et al.
    J Gastroenterol Hepatol, 1997 Dec;12(12):790-4.
    PMID: 9504887
    The objectives of the study were first, to determine if gastric emptying was altered in patients with functional dyspepsia with and without Helicobacter pylori infection compared with normal healthy volunteers; and second, to determine if there were further alterations in gastric emptying when the infection was eradicated. Gastric emptying was measured using a 99mtechnetium radiolabelled solid meal and gastric emptying time was measured as t1/2, viz. time taken for half the radiolabelled meal to be emptied from the stomach. The mean gastric emptying time for H. pylori-positive patients (n=20) was 56.4+/-24.8 min; H. pylori-negative patients (n=19) 67.8+/-31.8 min; and normal controls (n=20) 58.8+/-18.8min. No significant difference was obtained between the groups (ANOVA; P=0.348). Thirteen of 18 H. pylori-positive patients successfully eradicated the infection following treatment with omeprazole 40 mg o.m. and amoxycillin 500 mg t.d.s. for 2 weeks. The mean difference in the gastric emptying time before and after H. pylori eradication was 23.9+/-13.2 min (P= 0.556). There was no significant difference in the frequency of specific dyspeptic symptoms as well as the overall mean symptom score between the H. pylori-positive and -negative patients. Gastric emptying was not different between patients with functional dyspepsia and normal controls. Helicobacter pylori infection does not appear to affect gastric emptying in patients with functional dyspepsia.
  18. Goh KL, Cutler A, Chua AB, Ding RP, Kandasami P, Mazlam MZ, et al.
    J Gastroenterol Hepatol, 1999 Jan;14(1):32-8.
    PMID: 10029275
    The aim of the present study was to determine the cost-efficiency of different duodenal ulcer disease treatment practices in Malaysia. Six Malaysian gastroenterologists met to discuss the direct costs related to Helicobacter pylori (HP) eradication treatment. Five treatment strategies were compared: (i) histamine H2 receptor antagonists (H2RA), acid suppression therapy for 6 weeks followed by maintenance therapy as needed; (ii) bismuth triple + proton pump inhibitor (PPI), bismuth (120 mg, q.i.d.), metronidazole (400 mg; t.i.d.), tetracycline (500 mg, q.i.d.) for 7 days and PPI, b.i.d., for 7 days; (iii) OAC, omeprazole (20 mg, b.i.d.), amoxycillin (1000 mg, b.i.d.) and clarithromycin (500 mg, b.i.d.) for 7 days; (iv) OMC, omeprazole (20mg, b.i.d.), metronidazole (400mg, b.i.d.) and clarithromycin (500 mg, b.i.d.) for 7 days; and (v) OAM, omeprazole (20 mg, b.i.d.), amoxycillin (1000 mg, b.i.d.) and metronidazole (400 mg, b.i.d.) for 7 days. A decision tree model was created to determine which therapy would be the most cost-effective. The model considered eradication rates, resistance to anti-microbial agents, compliance and cost implications of treatment regimens, physician visits and ulcer recurrences during a 1 year time period assumption. The H2RA maintenance therapy was the most expensive treatment at Malaysian Ringgit (MR) 2335, followed by bismuth triple therapy (MR 1839), OMC (MR 1786), OAM (MR 1775) and OAC, being the most cost-effective therapy, at MR 1679. In conclusion, HP eradication therapy is superior to H2RA maintenance therapy in the treatment of duodenal ulcer disease. Of the HP eradication regimens, OAC is the most cost-effective.
  19. Goh KL, Boonyapisit S, Lai KH, Chang R, Kang JY, Lam SK
    J Gastroenterol Hepatol, 1995 1 1;10(1):92-7.
    PMID: 7620115
    We report the first double-blind, placebo-controlled study that assesses the efficacy and safety of omeprazole 20 mg daily in the maintenance treatment of duodenal ulcer. For the healing phase, 128 patients with endoscopically proven active duodenal ulcer and a history of three or more relapses during the 2 years prior to the study were treated until healing with omeprazole 40 mg daily for 2 and up to 8 weeks. One hundred and twenty-three patients whose ulcers were healed were randomized to receive omeprazole 20 mg daily (n = 60) or placebo (n = 63) for 12 months as maintenance treatment. Patients were interviewed at 3, 6, 9 and 12 months, and endoscopy was performed at 3, 6 and 12 months and whenever symptoms recurred. The healing rates of the 124 patients completing the healing phase were 84, 98 and 100% at 2, 4 and 8 weeks, respectively. During the maintenance phase, eight and four patients discontinued treatment from the omeprazole and placebo groups, respectively. The proportion of patients in remission in the omeprazole group and placebo group after 12 months were 94 and 9% respectively (life table estimates, P < 0.0001). No significant clinical or laboratory changes were observed in patients on therapy with omeprazole. Patients with a history of frequent relapses thus continued to have a very high relapse rate without prophylactic treatment. Omeprazole 20 mg daily was effective and safe in maintaining such patients in remission.
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