Search Results - (Author, Cooperation:K. Y. Ho)

2015-06-05

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Bacterial Toxins/pharmacology ; Cell Differentiation/drug effects ; Cell Lineage ; Cells, Cultured ; Clone Cells/cytology/metabolism ; Clostridium difficile/physiology ; Colon/cytology/drug effects ; Enterocolitis, Pseudomembranous/microbiology/pathology ; Epigenesis, Genetic/genetics ; Epithelium/drug effects/metabolism ; Fetus/cytology ; Genomic Instability/genetics ; Humans ; Intestine, Small/cytology ; Intestines/*cytology/drug effects ; Organoids/cytology/growth & development ; Stem Cells/*cytology/*metabolism

2018-02-09

BMJ Publishing Group

0017-5749

1468-3288

Medicine

Open access, Gut

1365-2826

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Corticotropin-releasing hormone and arginine vasopressin are known to interact in stimulating secretion of adrenocorticotropin-related peptides from corticotropes. However, the mechanism mediating this interaction is uncertain. Recently, evidence has been provided using a reverse haemolytic plaque assay that in rat pituitary cells, arginine vasopressin potentiates the effects of corticotropin-releasing hormone by increasing the percentage of target cells that secrete adrenocorticotropin. To determine whether a similar mechanism also operates in the sheep corticotrope, which is reportedly more sensitive to arginine vasopressin than that of the rat, a reverse haemolytic plaque assay for β-endorphin secretion was used to study the response of ovine corticotropes to stimulation by increasing doses of corticotropin-releasing hormone or arginine vasopressin (0.1 nM to 10.0 nM) alone or in combination.In the reverse haemolytic plaque assay, β-endorphin antiserum at 1:50 and complement at 1:10 were found to be optimal dilutions for plaque formation. A concentration-dependent response curve to corticotropin-releasing hormone was obtained with a significant increase in plaque area from basal to reach maximal levels at 1.0 nM. Arginine vasopressin also stimulated an increase in plaque area, however, plaques formed were significantly smaller than those caused by corticotropin-releasing hormone. Since in the reverse haemolytic plaque assay, plaque area is related to the amount of hormone secreted by the cell, results demonstrate that although corticotropin-releasing hormone and arginine vasopressin both stimulate β-endorphin secretion from ovine corticotropes, corticotropin-releasing hormone is a more potent secretagogue than arginine vasopressin in that it causes the formation of significantly larger plaques.The addition of arginine vasopressin to low concentrations of corticotropin-releasing hormone caused plaque areas to reach maximal levels at 0.1 nM whereas these levels were only attained at 1.0 nM when corticotropin-releasing hormone was used alone. Therefore, arginine vasopressin interacts with corticotropin-releasing hormone to increase corticotrope responses by increasing their secretory response to corticotropin-releasing hormone. These data are consistent with previous work suggesting that arginine vasopressin increases the expression of corticotropin-releasing hormone receptors on the corticotrope cell surface. However, no significant increase in the percentage of plaque-forming cells was seen with either corticotropin-releasing hormone or arginine vasopressin alone or in combination implying that there was no recruitment of previously non-secreting cells.

Electronic Resource

1600-0765

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

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 (µm) (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 (µm) (373.04 vs. 606.67, p 〈 0.05), higher lipid peroxidation concentration (µm) (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.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

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.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

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 pre-treatment 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.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

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.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

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 ≥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.

Electronic Resource

0304-8853

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0304-8853

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0304-8853

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

1432-1084

Key words: Peripheral contrast ; Enhanced MR angiography

Springer Online Journal Archives 1860-2000

Medicine

Abstract. Magnetic resonance angiography has taken a huge step forward since the introduction of contrast-enhanced MR angiography using gadolinium chelates. The more conventional MR angiographic techniques, such as time-of-flight and phase-contrast MR angiography, have been ousted by contrast-enhanced MR angiography in most vascular areas. However, in imaging the lower extremities, the major obstacle is the length of the vascular tree. In order to cover the entire peripheral vasculature, at least two to three fields of view are required. Using contrast-enhanced MR angiography, the best results are obtained if the vessels of interest are imaged during passage of a bolus of contrast material. Vessel-to-background contrast in subsequent acquisitions using subsequent injections of contrast material is hampered by recirculation and leakage of previously injected gadolinium, enhancing both the venous system and surrounding tissue. To overcome this problem several research groups have come up with various solutions. The three main strategies employed can be classified as either bolus catch, bolus chase, or bolus track techniques. The purpose of this article is to explain working mechanisms of the three bolus imaging strategies for imaging both inflow and outflow vessels of the lower extremities, to show their advantages and disadvantages, and to review results described in the literature in imaging patients using these techniques.

Electronic Resource

1432-1084

Key words: Peripheral occlusive vascular disease ; Peripheral MR angiography ; Time-of-flight MRA ; Contrast-enhanced MRA ; Gadolinium chelates

Springer Online Journal Archives 1860-2000

Medicine

Abstract. Atherosclerotic disease of the lower extremities is a common disorder in western society. Its debilitating nature calls for accurate diagnosis and treatment. The gold standard for diagnosing this disease by depiction of vessel morphology is X-ray angiography (either conventional or digital subtraction angiography). However, the invasive nature of this technique and the possible harmful effects of iodinated contrast agents have led to the idea that non-invasive MR angiography might be a good alternative for acquiring information about vessel morphology. Most extensively studied was time-of-flight MR angiography. Although first results with this technique were encouraging, it is now apparent that time-of-flight MR angiography is hampered by the virtue of which it exists, since blood flow not only generates vessel-to-background contrast, but is also the cause of disturbing artifacts. However, with the introduction of minimally invasive contrast-enhanced MR angiography, using gadolinium chelates to reduce the T1 of blood, image quality has improved dramatically. Moreover, using contrast-enhanced MR angiography, high-resolution three-dimensional data about the entire peripheral vascular tree can be obtained within several minutes, which might make MR angiography a true competitor of X-ray angiography as a diagnostic tool in the clinical work-up of a patient with complaints of peripheral atherosclerosis. The purpose of this article is to explain working mechanisms and usefulness of both time-of-flight and contrast-enhanced MR angiography.

Electronic Resource