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Biomedical subjects

K Y Ho

Publications and source records attributed to K Y Ho.

At least 19 recordsLinked to original sources
PubMed2005

Melatonin improves bowel symptoms in female patients with irritable bowel syndrome: a double-blind placebo-controlled study.

BACKGROUND: Melatonin is involved in the regulation of gastrointestinal motility and sensation. AIM: To determine the potential therapeutic effects of melatonin in irritable bowel syndrome (IBS). METHOD: Seventeen female patients satisfying the Rome II criteria for IBS were randomized to receive either melatonin 3 mg nocte or identically appearing placebo 1 nocte for 8 weeks, followed by a 4-week washout period and placebo or melatonin in the reverse order for another 8 weeks. Three validated questionnaires - the GI symptom, the sleep questionnaires and the Hospital Anxiety and Depression Scale - were used to assess symptom severity and to compute the IBS, sleep and anxiety/depression scores, respectively. RESULTS: Improvements in mean IBS scores were significantly greater after treatment with melatonin (3.9 +/- 2.6) than with placebo (1.3 +/- 4.0, P = 0.037). Percent response rate, defined as percentage of subjects achieving mild-to-excellent improvement in IBS symptoms, was also greater in the melatonin-treated arm (88% vs. 47%, P = 0.04). The changes in mean sleep, anxiety, and depression scores were similar with either melatonin or placebo treatment. CONCLUSIONS: Melatonin is a promising therapeutic agent for IBS. Its therapeutic effect is independent of its effects on sleep, anxiety or depression.

Adult↗
PubMed2005

Empirical treatment for the management of patients presenting with uninvestigated reflux symptoms: a prospective study in an Asian primary care population.

BACKGROUND: Data on Asian patients who present with reflux symptoms to their primary care physicians are limited. AIM: To determine whether empirical therapy without endoscopy is appropriate for patients who present to their primary care physicians with uninvestigated reflux symptoms without alarm symptoms. METHOD: Forty-seven patients presenting with uninvestigated, dominant reflux symptoms but without alarm features to their primary care physicians underwent endoscopy within 2 weeks of referral. Their endoscopic findings were compared with those of 162 primary care patients presenting with uninvestigated dominant dyspepsia. All patients, except those with ulcers, were treated with esomeprazole 20 mg b.d. for 2 weeks. Their treatment response was assessed at 2 weeks using a symptom score. RESULTS: Among patients with dominant reflux symptoms, 14 (30%) had erosive oesophagitis. No other clinically significant endoscopic findings were detected among them. In contrast, erosive oesophagitis and peptic ulcer were found in 13 (8%, P < 0.001 vs. reflux group), and 12 (7%, P = 0.06 vs. reflux group), respectively, of patients with dominant dyspepsia. Thirty-seven of forty-five (82%) of those with dominant reflux symptoms and 109 of 139 (78%; P = N.S. vs. reflux group) of those with dominant dyspepsia reported > or = 50% resolution of symptoms after esomeprazole treatment. CONCLUSIONS: Empirical proton pump inhibitor without endoscopy is reasonable for uninvestigated patients who present to primary care physicians with dominant reflux symptoms.

Adult↗
PubMed2005

Melatonin improves abdominal pain in irritable bowel syndrome patients who have sleep disturbances: a randomised, double blind, placebo controlled study.

BACKGROUND AND AIMS: Melatonin, a sleep promoting agent, is involved in the regulation of gastrointestinal motility and sensation. We aimed to determine if melatonin was effective in improving bowel symptoms and sleep disturbances in irritable bowel syndrome (IBS) patients with sleep disturbance. METHODS: Forty IBS patients (aged 20-64 years; 24 female) with sleep disturbances were randomly assigned to receive either melatonin 3 mg (n = 20) or matching placebo (n = 20) at bedtime for two weeks. Immediately before and after the treatment, subjects completed bowel, sleep, and psychological questionnaires, and underwent rectal manometry and overnight polysomnography. RESULTS: Compared with placebo, melatonin taken for two weeks significantly decreased mean abdominal pain score (2.35 v 0.70; p<0.001) and increased mean rectal pain threshold (8.9 v -1.2 mm Hg; p<0.01). Bloating, stool type, stool frequency, and anxiety and depression scores did not significantly differ after treatment in both groups. Data from sleep questionnaires and polysomnography showed that the two week course of melatonin did not influence sleep parameters, including total sleep time, sleep latency, sleep efficiency, sleep onset latency, arousals, duration of stages 1-4, rapid eye movement (REM) sleep, and REM onset latency. CONCLUSIONS: Administration of melatonin 3 mg at bedtime for two weeks significantly attenuated abdominal pain and reduced rectal pain sensitivity without improvements in sleep disturbance or psychological distress. The findings suggest that the beneficial effects of melatonin on abdominal pain in IBS patients with sleep disturbances are independent of its action on sleep disturbances or psychological profiles.

Abdominal Pain↗
PubMed2005

Melatonin attenuates stress-induced defecation: lesson from a rat model of stress-induced gut dysfunction.

Melatonin is known to alleviate stress and modulate gut motility. We investigated the modulating effects of melatonin on stress-induced gut dysfunction. One hundred Wistar rats were randomly assigned to five equal groups, receiving intraperitoneal injections of 0, 1, 10, 100 or 1000 microg kg(-1) melatonin, respectively. Fifteen minutes later, each group was divided again into four subgroups receiving no treatment, 0.25 mg luzindole (a non-selective melatonin receptor antagonist) intraperitoneally, wrap-restraint stress, and 10 mg kg(-1) serotonin intraperitoneally, respectively. Two hours later, serum serotonin, corticotropin-releasing factor (CRF) and melatonin levels, and faecal output were recorded. Results showed that intraperitoneal melatonin increased faecal output, but this effect was abolished by luzindole. In wrap-restraint group, prior intraperitoneal melatonin at doses of 100 or 1000 microg kg(-1) significantly inhibited stress-induced defecation. This effect was associated with corresponding reductions in serum serotonin and CRF concentrations. In serotonin-treated group, serotonin-induced defecation was also inhibited by melatonin. In conclusion, melatonin exhibited an excitatory effect on bowel output in rats placed under resting state, while attenuated defecation in those subjected to wrap-restraint stress or serotonin treatment. The inhibitory effects of melatonin on stress-induced defecation may stem from its antagonistic effect on stress-induced enhancement of serotonin and CRF secretion.

Animals↗
PubMed2005

Lipid peroxidation: a possible role in the induction and progression of chronic periodontitis.

OBJECTIVES: Reactive oxygen species (ROS) are implicated in the destruction of the periodontium during inflammatory periodontal diseases. The imbalance in oxidant/antioxidant activity may be a key factor in the damaging effects of ROS. This study aimed to determine the lipid peroxidation levels in gingival crevicular fluid and saliva, and glutathione (GSH) and glutathione peroxidase (GPx) in saliva in patients with chronic periodontitis. METHODS: Gingival crevicular fluid and saliva were collected from 13 patients and 9 healthy control subjects during the preliminary study, and from 21 patients during the subsequent study. Lipid peroxidation level, GSH level and GPx activity were determined by spectrophotometric assay. RESULTS: The preliminary study found that when comparing patients to healthy controls, the gingival crevicular fluid samples produced the following results, respectively: higher lipid peroxidation concentration (microm) (by sites: 167.55 vs. 53.71, p < 0.0001; by subjects: 151.99 vs. 50.66, p < 0.005) and total amount (pmol) (by sites: 93.02 vs. 8.47, p < 0.0001, by subjects: 80.44 vs. 7.84, p < 0.0005). In saliva samples, lower GSH concentration (microm) (373.04 vs. 606.67, p < 0.05), higher lipid peroxidation concentration (microm) (0.66 vs. 0.13, p < 0.0005), and no difference in GPx activity were found in patients than in those of healthy controls. The subsequent study showed statistically significant (p < 0.05) improvement of clinical periodontal parameters (plaque index, gingival index, probing attachment level, probing pocket depth and gingival crevicular fluid volume), decreases in gingival crevicular fluid lipid peroxidation levels (concentration and total amount) at the sites after the completion of phase 1 periodontal treatment. Similarly, the periodontal treatment resulted in a significant decrease of lipid peroxidation concentrations (p < 0.05), increase in GSH concentration (p < 0.001), and no change in GPx activity in saliva samples. CONCLUSION: The increased levels of lipid peroxidation may play a role in the inflammation and destruction of the periodontium in periodontitis.

Antioxidants↗
PubMed2005

Factors influencing cardiac auscultation proficiency in physician trainees.

INTRODUCTION: We assessed the accuracy of physician trainees in identifying different cardiac sounds and examined the factors influencing their cardiac auscultation proficiency. METHODS: A total of 106 physicians in the Family Medicine Training Programme were asked to identify 10 cardiac sounds played sequentially on the Littmann electronic stethoscope, which functioned as a surrogate patient. Their auscultation accuracy was scored numerically out of a maximum of 10. Demographical data of the physicians was collected prospectively. RESULTS: The mean (+/-SD) auscultation proficiency score of the study population was 4.0 +/- 1.7. Physicians who graduated in 1994 or earlier fared significantly poorer than those who obtained their Bachelor of Medicine and Bachelor of Surgery degrees between 1995 and 2000 (p-value equals 0.02). Auscultation proficiency was not related to current practice, previous years of primary care, cardiology, internal medicine or paediatric medicine postings, or cumulative years of postings. Normal heart sounds were most accurately identified. Prosthetic cardiac sounds were better identified than other extra-cardiac sounds while systolic murmurs were more accurately identified than diastolic murmurs. Tachycardia had the lowest identification rate. CONCLUSION: Our data suggest that cardiac auscultation skill declined with time, being significantly impaired eight years after graduation. We suggest that there is a need for retraining in the form of continuing medical education to address not only new knowledge and skills, but also basic skill competency.

Adult↗
PubMed2005

Multimodal antiemetic therapy and emetic risk profiling.

INTRODUCTION: Postoperative nausea and vomiting (PONV) is a common problem with no simple solution. This review highlights factors that are known to increase the risk of PONV. It examines the various data on pharmacological and non-pharmacological methods that have been used to prevent PONV. METHODS: Peer-reviewed journals on the subject were covered. CONCLUSION: Patient, surgical and anaesthetic factors increase the risk of PONV. While patient and surgical factors are understandably difficult to control, a multimodal approach involving both pharmacological and non-pharmacological interventions has been successfully adopted to reduce the incidence of PONV. Various factors have been identified to categorise patients into different profiles to determine their risk of PONV. Perioperative strategies can then be targeted at these patient groups.

Anesthesia, General↗
PubMed2001

Need for background suppression in contrast-enhanced peripheral magnetic resonance angiography.

To determine if background suppression is beneficial for peripheral magnetic resonance angiography (pMRA), nonsubtracted, subtracted, and fat-saturated contrast-enhanced (CE) pMRA were compared in 10 patients with peripheral arterial disease. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs), as well as venous enhancement and subjective interpretability, were determined in a station-by-station fashion for each technique. In three patients X-ray angiography was available as a standard of reference. SNRs and CNRs were significantly higher for fat-saturated vs. the other two techniques (P = 0.005). Subjective interpretability was best for subtracted data sets in the lower-leg station. In the iliac station, fat-saturated data sets were considered to have significantly lower interpretability than subtracted data sets. Venous enhancement occurred significantly more often in the lower-leg station with the fat-saturated technique. The value of subtraction depends on the hardware one has available and is a useful tool if dedicated surface coils are used. Background suppression by means of magnitude subtraction leads to the best lower-leg image interpretability. Care must be taken to avoid venous enhancement in the lower-leg station when using fat saturation.

Arterial Occlusive Diseases↗
PubMed2001

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis.

The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis.

Actinobacillus↗
PubMed2001

A prospective study of p53 expression and its correlation with clinical response of radiotherapy in nasopharyngeal carcinoma.

OBJECTIVES/HYPOTHESIS: Nasopharyngeal carcinoma (NPC) is a common malignant neoplasm of the head and neck that occurs in people in the southeastern Asian area, including Taiwan. The significant association of p53 expression in NPC suggested that p53 overexpression seemed to occur at an early stage in the development of NPC. Alterations of p53 status were probably the most commonly encountered in head and neck carcinomas, and there was extensive evidence that p53 status might determine tumor response to therapy. Ionizing radiation was studied extensively for the relationship between its damaging effect and p53 status in human cancer cells. STUDY DESIGN: This study was carried out to investigate whether there was any correlation between overexpression of p53 protein and locoregional tumor response in patients with NPC treated with 7000 cGy of radiotherapy. METHODS: Sixty-eight patients (50 males, 18 females) with NPC who were diagnosed and treated with radiotherapy were studied prospectively. Before they had received a radiation dose of 7000 cGy in 35 fractions, five fractions a week, p53 status from a nasopharyngeal biopsy was studied using immunohistochemical staining (IHC). RESULTS: The locoregional response rate of primary tumor was analyzed statistically. Forty-seven patients (69.1%) showed positive p53 staining in their tumors. There were 5 positive stains in 6 squamous cell carcinomas (SCC; 83.3%), 34 positive in 53 non-keratinizing carcinomas (NKC; 64.2%), and 8 positive in 9 undifferentiated carcinomas (UC; 88.9%). The mean ages for patients with three different histopathologies were 48.5, 46.1, and 61.1 years. There were 8 patients (7 positive stains, 1 negative stain) with residual tumor after radiotherapy and all were NKC (6 males, 2 females). Therefore, the clinical response rate of primary tumor was 85.1% in positive p53 immunostaining (40 of 47 cases), 95.2% in those with no immunostaining (20 of 21 cases); the former was poorer in locoregional tumor response than the latter, but there was no significant difference (P > .05, chi2 test). CONCLUSIONS: We conclude that there is no statistically significant correlation in locoregional response of primary tumor between p53 overexpression and radiotherapy in patients with NPC (P > .05, Fisher exact test).

Adolescent↗
PubMed2001

Antimicrobial activity of tannin components from Vaccinium vitis-idaea L.

Reactive oxygen species have been implicated as important pathological mediators in many clinical disorders, including periodontal disease. As a possible alternative for the treatment of periodontal disease, the antimicrobial activity of six tannins isolated from Vaccinium vitis-idaea L., with confirmed antioxidant activity, were assayed by the agar dilution method against selected periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. The results showed that epicatechin-(4beta-->8)-epicatechin-(4beta-->8, 2beta-->O-->7)-catechin had strong antimicrobial activity against P. gingivalis and P. intermedia, but not A. actinomycetemcomitans. The other tannins tested did not show antimicrobial activity. We conclude that tannins isolated from V. vitis-idaea L. with antimicrobial activity could potentially be used for the treatment of periodontal disease.

Aggregatibacter actinomycetemcomitans↗
PubMed2001

Palliation of malignant gastric outlet obstruction caused by gastric cancer with self-expandable metal stents.

Gastric carcinoma is among the most common cancers worldwide. Surgery remains the mainstay of potentially curative treatments. Unfortunately, most patients have an advanced form of the disease. We evaluated our experience in palliating malignant gastric outlet obstruction caused by gastric cancer with expandable metal stents (Wallstent Enteral; Boston Scientific, Singapore). Six patients with a median age of 68 years (range, 45-88) underwent the procedure. Three had metastatic gastric cancer; two recurrent gastric cancer; and one locally advanced gastric cancer with poor comorbid status. After the procedure, five of the six patients were able to resume an oral feeding within 24 hours. One patient with gastric dysmotility caused by linitus plastica required nasogastric tube feeding. Three patients died during a median follow-up period of 4 weeks (range, 2-8). The other three patients were still well at a median follow-up period of 10 weeks (range, 5-12). There was no procedure-related mortality or morbidity, nor was there any stent migration or blockage in any of these patients. In conclusion, palliation of malignant gastric outlet strictures caused by gastric cancer with expandable metal stents is an effective and safe alternative to surgery, particularly in patients with postgastrectomy anastomotic recurrence and in those who are poor candidates for surgery. Patients who are not expected to survive beyond 1 month and those with linitus plastica and associated gastric dysmotility may not be appropriate candidates for such a procedure.

Aged↗
PubMed2001

Expression of transforming growth factor-beta 1 and alpha-smooth muscle actin of myofibroblast in the pathogenesis of nasal polyps.

The pathophysiology of nasal polyps remains unclear, but recent work suggests that many cytokines are produced in nasal polyps (NPs) and that they may play various important roles in the pathogenesis of NPs. Transforming growth factor-beta 1 (TGF-beta 1), secreted by many inflammatory cells, is a potent inducer of myofibroblasts. Myofibroblasts express alpha-smooth muscle actin (alpha-SMA) and a source of extracellular matrix (ECM). In this study, we investigated a potential link between inflammation and the growth process in human NPs. Sixteen patients who were affected by NPs and who had undergone functional endoscopic sinus surgery were included in this study. Nasal mucosa of inferior turbinate (NM) of 10 patients who had received rhinoplasty or turbinectomy for other disease was used as the control. alpha-SMA and TGF-beta 1 were detected using immunohistochemistry and the number of labeled cells were counted (alpha-SMA and TGF-beta 1 indices). The expression of alpha-SMA and TGF-beta 1 indices found in NPs and NM was compared using Student's t-test. In our study, alpha-SMA and TGF-beta 1 indices were found to be significantly higher in nasal polyps than in nasal mucosa. TGF-beta 1 produced by inflammatory cells can influence the development of myofibroblasts which in turn can induce extracellular matrix accumulation and, therefore, TGF-beta 1 plays a important role in the formation of nasal polyps.

Actins↗
PubMed2000

Three-dimensional contrast-enhanced moving-bed infusion-tracking (MoBI-track) peripheral MR angiography with flexible choice of imaging parameters for each field of view.

A technique to image peripheral arteries with flexible choice of scan parameters for separate stations was developed based on moving-bed single-bolus three-dimensional gradient-recalled echo magnetic resonance angiography. A volunteer study yielded higher signal- and contrast-to-noise ratios, less venous enhancement, and better subjective interpretability compared with imaging with fixed parameters for each station. Additionally, six patients were imaged to test the feasibility of the new method in a clinical setting. Imaging peripheral arteries with the new technique in volunteers yielded better image quality and is feasible for patients.

Adult↗