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Biomedical subjects

S C Chung

Publications and source records attributed to S C Chung.

At least 109 records · Page 6Linked to original sources
PubMed1997

Stigmata of hemorrhage in bleeding peptic ulcers: an interobserver agreement study among international experts.

BACKGROUND: Stigmata of hemorrhage predict rebleeding and outcome of patients with bleeding peptic ulcers. There are variabilities in reported incidences of stigmata and their respective rebleeding risks. We sought to study the interobserver agreement among experts. METHODS: Between June 1994 and July 1994, 100 consecutive patients with bleeding peptic ulcers underwent videoendoscopy within 24 hours of their admissions. An edited videotape of these ulcers was compiled and sent to an international panel of 14 experts. They independently rated these ulcers exclusively into one of the six categories: spurting, oozing, nonbleeding visible vessel, adherent clot, flat pigmented spot, or clean based. Agreement between any two experts was expressed by a kappa estimate (kappa). Agreements over individual stigmata and a composite kappa estimate (kappa(w)) signifying overall agreement were also computed. RESULTS: Out of the possible 91 pairwise kappa estimates among 14 experts, 35 (38.5%) were less than or equal to 0.40, indicating poor agreement. None of the kappa estimates was greater than 0.75. Composite kappa estimates for individual stigmata were as follows: spurting kappa = 0.664, oozing kappa = 0.420, nonbleeding visible vessel kappa = 0.342, adherent clot kappa = 0.426, flat pigmented spot kappa = 0.393, and clean-based ulcer kappa = 0.371. The weighted kappa estimate was 0.426. CONCLUSION: Agreement between experts was poor in more than a third of occasions. Although the overall interobserver agreement was fair (0.4 < kappa < 0.75), agreements for nonbleeding visible vessels, flat pigmented spots, and clean-based ulcers were poor.

Endoscopy, Digestive System↗
PubMed1997

Regulation of thyroid hormones in the secretion of insulin and gastric inhibitory polypeptide in male rats.

The effect of thyroid hormones on glucose-induced secretion of gastric inhibitory polypeptide (GIP) and insulin was studied. Male rats were thyroidectomized (Tx) or sham Tx. Sham Tx rats were injected with either propylthiouracil ([PTU] 20 mg/kg intraperitoneally) or saline for 2 weeks. In addition, thyroid-intact rats were injected intravenously with triiodothyronine ([T3]5 microg/kg) or saline 10 minutes before an oral glucose load (3.2 g/kg). Blood samples were collected from each animal via a jugular catheter at 0, 10, 20, 30,45, 60, and 90 minutes following glucose ingestion. Plasma levels of GIP and insulin were measured by specific radioimmunoassays (RIAs). Thyroidectomy-induced hypothyroidism increased the basal level of plasma GIP, but decreased that of insulin. Insulin levels at 10, 20, and 30 minutes following oral glucose were lower in hypothyroid rats than in euthyroid rats. Conversely, GIP levels at 60 and 90 minutes following glucose ingestion in PTU-induced hypothyroid rats were higher than those in euthyroid rats. Furthermore, glucose-stimulated insulin secretion was unaltered by pretreatment with T3, whereas the glucose-induced increase in plasma GIP was completely abolished by preinjection of T3 in thyroid-intact rats. These results suggest that thyroid functions are involved in the regulation of insulin and GIP secretion in rats.

Animals↗
PubMed1997

Analysis of acoustic noise in MRI.

Acoustic or sound noise due to gradient pulsing has been one of the problems in magnetic resonance imaging (MRI), both in patient scanning as well as in many areas of psychiatric and neuroscience research such as functional MRI. Our recent observations in functional MRI for the visual and motor cortex show very different results with sound noise in comparison with the results obtained without sound noise. Although a number of ideas have been suggested in the literature about the possible elimination or reduction of sound noise, progress has been slow due to the basic role of gradient pulsing in MR imaging. Before we tackle the sound-noise-reduction problem, we believe that a systematic study of sound or acoustic noise behavior will provide important information for future endeavors in this area of research in MRI systems, in both commercial and research systems. Therefore, we report on some typical behavior of sound noise observed from MRI scanners and the analyses of their characteristics. Data are obtained both from a commercial MRI scanner (GE Signa 1.5-T EPI system) as well as a research-type MRI scanner (KAIS 2.0-T) developed at a university laboratory setting.

Magnetic Resonance Imaging↗
PubMed1997

Biliary infection.

Biliary infections are common conditions that can be life threatening. In the past, many of these conditions mandated emergency surgery, but advances in endoscopic and radiological techniques have allowed some of these to be managed in a minimally invasive fashion. Acute cholangitis is caused by infection in an obstructed biliary tree. Endoscopic drainage, together with broad-spectrum antibiotics, has replaced emergency common duct exploration and T-tube drainage as standard treatment. Oriental cholangitis, sclerosing cholangitis and AIDS-related cholangitis are some of the variants of cholangitis. Pyogenic liver abscesses complicating cholangitis can be managed by radiological percutaneous drainage. Close collaboration between surgeons, endoscopists and radiologists is the key to success in managing biliary infections.

Acute Disease↗
PubMed1997

One-week antibiotics versus maintenance acid suppression therapy for Helicobacter pylori-associated peptic ulcer bleeding.

Bleeding peptic ulcer is the most important cause of upper gastrointestinal bleeding. Our aim was to compare the effect of anti-Helicobacter therapy with maintenance treatment of H2-receptor antagonist in the prevention of relapses of ulcer and bleeding. Patients with bleeding duodenal or gastric ulcers and H. pylori infection were randomized to receive either a one-week course of triple therapy with bismuth subcitrate, metronidazole, and tetracycline plus ranitidine or a six-week course of ranitidine 300 mg/day. After the ulcers healed, the antibiotic-treated patients were not given any medication, whereas the ranitidine-treated patients continued to receive a maintenance dose of 150 mg/day. One hundred twenty-six patients were randomized to receive anti-Helicobacter therapy and 124 patients to receive long-term ranitidine. H. pylori eradication was achieved in 98.2% in those who received triple therapy and 6.1% in those who received ranitidine (P < 0.0001). At the six-week follow-up, ulcer healing was documented in 88.2% in those who received triple therapy and 86.1% in those who received ranitidine (P = 0.639). Recurrent ulcer developed in nine of the ranitidine-treated patients and three of them presented with recurrent upper gastrointestinal bleeding. One patient in the antibiotic group developed recurrent ulcer without rebleeding (P = 0.01). It is concluded that eradication of H. pylori is sufficient for the prevention of recurrent bleeding ulcers.

Adult↗
PubMed1997

Large paraesophageal varices on endosonography predict recurrence of esophageal varices and rebleeding.

BACKGROUND & AIMS: Recurrence of varices and rebleeding after endoscopic therapy is very common. Data on the prediction of recurrent varices after initial obliteration by endoscopic therapy are few. The aim of this study was to correlate the presence and the size of paraesophageal varices (PEVs) in patients after endoscopic variceal ligation with recurrent varices and rebleeding. METHODS: Forty patients who underwent endoscopic banding ligation for esophageal variceal bleeding were studied by endosonography within 4 weeks after obliteration of varices. PEVs were classified as none, small, or large (maximum diameter, > or =0.5 cm). Esophagoscopy and endosonography were then repeated every 6 months for up to 1 year. RESULTS: Two patients (5%) were not detected to have PEVs. Small and large PEVs were identified in 24 (60%) and 14 (35%) patients, respectively. During the follow-up period of 1-year, recurrent submucosal esophageal varices were detected in 24 patients, including 13 patients (93%) with large PEVs and 11 patients (46%) with no or small PEVs (P = 0.0019). Recurrent bleeding occurred in 6 patients (43%) with large PEVs and in 3 patients (12%) with small PEVs (P = 0.044). CONCLUSIONS: Patients with large PEVs have a higher risk of developing recurrent varices and rebleeding.

Adult↗
PubMed1997

Endoscopic surgery of the oesophagus.

Conventional surgical access to the oesophagus often requires a thoracotomy. The application of techniques borrowed from laparoscopic surgery allows transthoracic dissection of oesophagus without thoracotomy. These techniques are useful in treatment of oesophageal leiomyomas, motility disorders and iatrogenic perforations. Oesophageal resection for cancer can be accomplished using minimal access, either thoracoscopically or with the aid of an operating mediastinoscope. Whether these techniques should replace transthoracic or transhiatal oesophagectomy for most patients with cancer remains to be seen.

Endoscopy↗
PubMed1997

Does smoking predispose to peptic ulcer relapse after eradication of Helicobacter pylori?

OBJECTIVES: To investigate whether smoking would increase ulcer recurrence after eradication of Helicobacter pylori (H. pylori) without maintenance acid-suppression therapy. METHODS: A total of 287 patients, 256 patients with duodenal ulcers and 31 patients with gastric ulcers, were followed-up for up to 18 months after ulcer healing and successful eradication of H. pylori. There were 83 smokers (defined as smoking > or = 10 cigarettes/day) and 204 patients who never smoked or stopped smoking after the diagnosis of peptic ulcer disease. None were taking nonsteroidal anti-inflammatory drugs or receiving maintenance acid suppression therapy. Endoscopy was repeated either at the end of the follow-up period or when ulcer symptoms recurred. RESULTS: Of the 83 smokers, 3 (3.6%) had ulcer recurrence, which included two duodenal ulcers and one gastric ulcer. Of the 204 nonsmokers, 4 (2.0%) had ulcer relapse, and all being recurrent duodenal ulcers. Four smokers (4.8%) and nine nonsmokers (4.4%) had recurrence of H. pylori infection after 10-18 months. There was no significant difference in ulcer relapse or recurrence of H. pylori infection between smokers and nonsmokers. CONCLUSIONS: Cigarette smoking did not increase the recurrence of peptic ulcers after eradication of H. pylori.

Adolescent↗
PubMed1997

Comparison of muscle activity and occlusal contacts during maximal and habitual clenching in varied chair positions.

The activity of anterior temporal muscle, the number of tooth contacts, and total duration of closure during maximal and habitual clenching were studied in varied chair positions. Fifteen subjects were evaluated. The means for the muscle activity of anterior temporal muscle during habitual clenching were 63.5-73.5% of maximum muscle activity. The number of tooth contacts and total duration of closure were significantly increased as biting pressure was increased from habitual to maximal clenching. No significant differences were detected in all variables among varied chair positions. The above results also suggested that occlusal instability was very common. Further research is required to explain the relationship, if any, of these variables to craniomandibular disorders.

Adult↗
PubMed1996

Risk of further ulcer complications after an episode of peptic ulcer bleeding.

To identify the risk factors for developing recurrent ulcer complications after recovery from an episode of peptic ulcer bleeding 611 patients admitted with peptic ulcer bleeding were studied. Some 557 (91 per cent) were discharged without operation. A total of 22 patients were lost to follow-up and five were excluded as maintenance H2 blockers were required. Of the remaining 530 patients at risk, 169 (32 per cent) developed another complication (166 bleeding, three perforations) over a median follow-up period of 36 months. Patients with duodenal ulcers at the time of bleeding, previous history of peptic ulcer, previous bleeding, history of dyspepsia longer than 3 months, and a short interval between previous ulcer complications and the index bleed were more likely to develop further complications. Sex, age, smoking, coexisting illness, non-steroidal anti-inflammatory drugs intake and time taken to achieve ulcer healing had no predictive value.

Adolescent↗
PubMed1996

High prevalence of Helicobacter pylori infection in duodenal ulcer perforations not caused by non-steroidal anti-inflammatory drugs.

There has been controversy regarding the relationship between Helicobacter pylori and perforated peptic ulcer, which is known to have a high recurrence rate if only simple patch repair is performed. The aim of this study was to evaluate the association between H. pylori infection and intake of non-steroidal anti-inflammatory drugs (NSAIDs) in patients with perforated duodenal ulcers. Of the 73 patients recruited over a 16-month period, 51 (70 per cent) had evidence of H. pylori infection by intraoperative gastroscopy and antral biopsies. The infection rate rose to 80 per cent if NSAID users were excluded. The H. pylori-infected group was significantly younger (mean 47.6 versus 62.5 years), with a male preponderance (49 of 51 versus 14 of 22 patients), and had significantly less NSAID consumption (three of 51 versus ten of 22) and more prolonged dyspepsia (40 of 51 versus ten of 22), compared with H. pylori-negative patients. H. pylori infection probably plays an important role in the causation of non-NSAID-induced duodenal ulcer perforation. Whether eradication of the bacteria can alleviate the strong ulcer diathesis in this subgroup of patients is unknown.

Aged↗
PubMed1996

NMR functional imaging using a tailored RF gradient echo sequence: a true susceptibility measurement technique.

The tailored radio frequency gradient echo (TRFGE) technique that has been used in venography (Cho et al., Magn. Reson. Med. 28, 25-38, 1992; Ro, Cho, Magn. Reson. Med. 28, 237, 1992) is applied to functional imaging. The TRFGE technique has the advantage that it is sensitive to the field gradient created by the susceptibility effect, thereby enhancing only the signals from the regions with local field gradient. In addition, the method is insensitive to the in-flow effect, especially from the arterial blood. The latter further simplifies the functional MRI data analysis. The TRFGE sequence is, therefore, suitable for functional MR imaging for which true susceptibility effect measurements are of prime importance. To examine the TRFGE functional imaging systematically, experiments with various imaging parameters such as flip angle alpha, repetition time, and echo time were performed and the results were compared with the data obtained from the conventional gradient echo functional MR imaging. The experimental results shown were all obtained from human volunteers with a 2.0T whole body MRI system.

Arousal↗
PubMed1996

Somatostatin reduces gastric mucosal blood flow in patients with portal hypertensive gastropathy: a randomized, double-blind crossover study.

Agents which decrease gastric mucosal blood flow (GMBF) are postulated to have beneficial effects in arresting gastrointestinal bleeding in cirrhotic patients with portal hypertension. Our objective was to test the hypothesis that in a dose that significantly lowers wedged hepatic venous pressure (WHVP), a bolus injection of somatostatin will significantly decrease GMBF in patients with portal hypertensive gastropathy (PHG). In this placebo-controlled, double-blind, crossover study, 20 cirrhotic patients with PHG were randomly assigned to receive either somatostatin followed by placebo (Group A) or placebo followed by somatostatin (Group B). Wedged hepatic venous pressure was monitored. GMBF in the antrum and corpus was assessed by reflectance spectrophotometry. Indices of hemoglobin concentration (IHb) and indices of oxygen content (ISO2) were recorded. Nine patients were assigned to Group A, and 11 to Group B. Mild PHG was seen in 16 patients, and severe PHG in 4 patients. Baseline WHVP, IHb, and ISO2 were similar in both treatment groups. Wedged hepatic venous pressure (WHVP) was significantly lowered [median, 17.6%; interquartile range (-27.0,-12.6%); P = 0.0008] after a 250-microg bolus injection of somatostatin. This dose of somatostatin significantly reduced IHb both in the antrum [-10.2% (-23.4, 0.4%)] and in the corpus [-5.8% (-16.6, 5.6%)] compared to placebo (P = 0.02 and 0.04, respectively). Intravenous bolus injection of 250 microg somatostatin significantly reduces WHVP and GMBF in patients with PHG. Whether this ability to decrease the GMBF in PHG makes somatostatin an effective treatment in acute gastrointestinal bleeding in PHG deserves to be studied.

Aged↗
PubMed1996

Dual therapy versus triple therapy for Helicobacter pylori-associated duodenal ulcers.

We compared the ulcer healing effect and eradication of H. pylori by one-week triple therapy of bismuth, metronidazole, and tetracycline with two-week dual therapy of amoxicillin and omeprazole. One hundred twelve patients with confirmed H. pylori infection and duodenal ulcers were recruited in a prospective, randomized, single-blinded trial. Ulcer healing, eradication of H. pylori in the stomach six weeks after randomization and side effect reported by patients during the therapy. Duodenal ulcers were healed in 44 of 49 (89.8%, 95% CI, 81.3-98.3 %) patients receiving triple therapy and in 44 of 53 (83.0%, 95% CI, 72.9-93.1%) patients receiving dual therapy (P=0.32). H. pylori was successfully eradicated in 41 of 49 (83.6%, 95% CI 73.4-94%) patients and in 40 of 53 (75.5%, 95% CI 63.9-87.1%) patients in the triple therapy group and the dual therapy group respectively (P=0.31). Side effects experienced by patients who received triple therapy were significantly more frequent than those who received dual therapy (P=0.0076). In conclusion, a two-week course of omeprazole and amoxicillin achieves a comparable rate of H. pylori and ulcer healing with fewer side effect.

Adolescent↗
PubMed1996

Absorbable clips for cystic duct ligation in laparoscopic cholecystectomy.

BACKGROUND: The efficacy and applicability of an absorbable polydioxanone (PDS) clip for cystic duct ligation were evaluated in 297 patients undergoing laparoscopic cholecystectomy. METHODS: The indications for cholecystectomy were symptomatic gallstones (179 patients), acute cholecystitis (67), biliary pancreatitis (23), acute cholangitis (24), and gallbladder polyp (4). RESULTS: Twenty-five patients required conversion to open surgery (8.4%). The conversion rate was 2.7% for uncomplicated and 17.5% for complicated gallbladder diseases. Of the 272 patients with laparoscopic cholecystectomy, the cystic ducts were successfully ligated with PDS clips in 227 patients (83.5%). The success rate was higher in uncomplicated (163/178) than in complicated (64/94) gallbladder diseases (chi square = 24.6, P < 0.001). There was no clip-related complication on follow-up (range 0.4-39.2, median 17.5 months). In 45 patients, PDS clip failed. They were treated with endoloop (14 patients), Roeder slip knot (13), metallic clips and endoloop (8), metallic clips alone (6), and intracorporeal tie (4). CONCLUSIONS: The PDS clip is effective and applicable to the majority of patients. It should be attempted first because of the ease of application.

Absorption↗
PubMed1996

Laparoscopic truncal vagotomy and gastroenterostomy for pyloric stenosis.

BACKGROUND: Gastric outlet obstruction secondary to chronic duodenal ulceration is an indication for surgery as conservative management with balloon dilatation frequently fails. The standard operation is truncal vagotomy and a drainage procedure. However, development of minimally invasive surgery has revolutionized the surgical approach to this clinical problem. METHODS: Twelve male patients with pyloric stenosis secondary to duodenal ulceration underwent laparoscopic truncal vagotomy and gastrojejunostomy. The perioperative and long term outcome of this group of patients were analyzed. RESULTS: The median operating time was 210 (range 180 to 240) minutes. Median postoperative stay was 6 (range 4 to 41) days. Conversion to laparotomy was necessary in one patient. Delayed gastric emptying occurred in two patients but resolved on conservative measures. At a median postoperative followup of 6 (range 1 to 12) months all patients had a good symptomatic outcome (Visick grades I or II). CONCLUSIONS: Laparoscopic truncal vagotomy and gastrojejunostomy is a feasible technique. Intermediate followup shows good symptomatic results when used for pyloric stenosis.

Adult↗