Biomedical subjects

A S Cheng

Publications and source records attributed to A S Cheng.

9 recordsLinked to original sources

PubMed2001

Up-regulation of cyclooxygenase-1 and -2 in human gastric ulcer.

BACKGROUND: The expression of cyclooxygenase (COX) in human gastric ulcers is unknown. AIM: To study the expression and cellular localization of cyclooxygenase in human gastric ulcers. METHODS: A total of 38 surgical gastric ulcer specimens were studied; 20 were Helicobacter pylori-positive and 18 were associated with NSAID use. Twenty non-ulcerated, histologically normal gastric specimens were used as controls. The cellular localization of COX-1 and COX-2 were determined by immunohistochemistry and double immunofluorescence. Cyclooxygenase messenger RNA (mRNA) was measured by reverse transcription-polymerase chain reaction and localized by in situ hybridization. RESULTS: In control specimens, COX-1 was detected in stromal cells in the lamina propria. There was focal and weak immunostaining for COX-2 in the foveolar epithelium. At the ulcer edge, COX-1 was significantly increased in lamina propria cells whereas COX-2 was strongly expressed in the hyperplastic foveolar epithelium in H. pylori- and non-steroidal anti-inflammatory drugs (NSAID)-associated ulcers. At the ulcer base, there was strong expression of COX-1 and COX-2 in myofibroblasts, macrophages and endothelial cells in the granulation tissue, irrespective of H. pylori status or NSAID use. Messenger RNA of COX-1 and COX-2 were demonstrated by reverse transcription-polymerase chain reaction. Double immunofluorescence and in situ hybridization confirmed the cellular localization of cyclooxygenase at protein and mRNA levels, respectively. CONCLUSION: Both COX-1 and COX-2 are up-regulated in human gastric ulcers.

Adult↗

PubMed2001

Expression and cellular localization of COX-1 and -2 in Helicobacter pylori gastritis.

BACKGROUND: There are conflicting reports on the expression of cyclooxygenase in Helicobacter pylori infection. AIM: To evaluate the expression of COX-1 and COX-2 in H. pylori gastritis at messenger RNA (mRNA) and protein levels. METHODS: Endoscopic gastric biopsies were obtained from patients with non-ulcer dyspepsia. The levels of COX-1 and COX-2 mRNA were compared between H. pylori-infected and uninfected specimens using reverse transcription-polymerase chain reaction. The immunohistochemical findings were correlated with the cellular localization of cyclooxygenase mRNA using in situ hybridization. RESULTS: A total of 40 H. pylori-infected and 40 uninfected specimens were studied. mRNA of COX-2 but not COX-1 was elevated in H. pylori-infected mucosa. COX-1 was localized to the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria. COX-2 was barely detectable in uninfected mucosa but was strongly expressed in the foveolar and glandular epithelia in H. pylori gastritis. CONCLUSION: Cyclooxygenase-1 is expressed in the mononuclear inflammatory, endothelial and smooth muscle cells in the lamina propria irrespective of the H. pylori status. By contrast, H. pylori induces COX-2 expression in the foveolar and glandular epithelia.

Adult↗

PubMed2001

A prospective study of early tactile stimulation after digital nerve repair.

Forty-nine patients with 65 digital nerve injuries were randomized into two groups after nerve repair. Group 1 received early tactile stimulation and Group 2 was a control group. The patients were assessed prospectively for 6 months for recovery of functional sensibility. Tactile stimulation in Group 1 was provided from 3 weeks after nerve repair with a specially designed rotating tactile stimulator and a pocket tactile stimulator. Constant two-point discrimination, moving two-point discrimination, and cutaneous pressure threshold were measured and sensibility was graded with the Medical Research Council (UK) sensibility grading. At 6 months, 68.8% of patients in Group 1 had a Medical Research Council grading of S3+ or S4 sensibility compared with 36 % in Group 2. With this prospective randomized study, the value of sensory reeducation in improving sensibility after digital nerve injury was confirmed. Starting tactile stimulation from the early postoperative period is recommended; however, use of the rotating tactile stimulator and pocket tactile stimulation need additional study.

Adult↗

PubMed2000

Cyclooxygenase-2 expression in Helicobacter pylori-associated premalignant and malignant gastric lesions.

Expression of cyclooxygenase-2 (COX-2) in various stages of the Helicobacter pylori-associated gastric carcinogenesis pathway has not been elucidated. We investigated the distribution and intensity of COX-2 expression in premalignant and malignant gastric lesions, and monitored the changes after H. pylori eradication. Gastric biopsies from H. pylori-infected patients with chronic active gastritis, gastric atrophy, intestinal metaplasia (IM), gastric adenocarcinoma, and noninfected controls were studied. Expression of COX-2 was evaluated by immunohistochemistry and in situ hybridization. Endoscopic biopsies were repeated 1 year after successful eradication of H. pylori in a group of IM patients for comparing COX-2 expression and progression of IM. In all H. pylori-infected patients, COX-2 expression was predominantly found in the foveolar and glandular epithelium and, to a lesser extent, in the lamina propria. In the noninfected group, only 35% of cases demonstrated weak COX-2 expression. Intensity of COX-2 was not significantly different between the chronic active gastritis, gastric atrophy, IM, and gastric adenocarcinoma groups. In 17 patients with IM, COX-2 expressions in the epithelial cells and stromal cells were reduced 1 year after H. pylori eradication. However, the changes in COX-2 expression did not correlate with progression/regression of IM. Both premalignant and malignant gastric lesions demonstrate strong COX-2 expression. Successful eradication of H. pylori leads to down-regulation of COX-2 expression but failed to reverse IM at 1 year.

Adenocarcinoma↗

PubMed1993

Visual losses in early age-related maculopathy.

Age-related maculopathy (ARM) can be considered a transition from normal retinal changes to pathological processes. It is important to recognize patients who have progressed beyond a normal state in order to provide appropriate clinical management. This pilot study considers the clinical dilemma of diagnosing and monitoring early ARM. We carried out a controlled study and tested the visual functions of 11 pre-ARM (PARM) and 11 early ARM subjects. Apart from compromised visual acuity, losses in central visual field, color vision, and visual adaptation were also recorded in our ARM subjects. We found a low contrast (LC) Amsler grid to be most sensitive to central field defects and that the desaturated panel D-15 gave too many false positives among normal elderly subjects. Our results indicate foveal sparing in early ARM and question the capacity of acuity assessment to reflect early functional changes adequately. A clinical battery is recommended to detect and monitor ARM.

Adaptation, Ocular↗

PubMed1993

Preliminary results from a field study of wild Guizhou snub-nosed monkeys (Rhinopithecus brelichi).

The Guizhou snub-nosed monkey, Rhinopithecus brelichi, is a large-bodied colobine confined to the subtropical semi-deciduous forests of Fanjing Mountain Reserve in Guizhou province, southwest China. Field work beginning in 1979 and including 10 months of intensive study in 1991 has revealed several aspects of the behavior and ecology of this species that are distinct from other colobines, including the closely related species R. roxellana and R. bieti. The Guizhou snub-nosed monkey is arboreal, traveling through the trees by quadrupedal walking, climbing, leaping, semibrachiation and (occasionally) by full brachiation. Terrestrial locomotion is use occasionally. Social organization centers around family groups of 5-10 individuals with a single adult male. Many family groups range and rest together in large, semicohesive bands. These bands may split up or coalesce temporarily to form large aggregations of over 400 animals and perhaps more. All-male groups of 2-5 adult or subadult males are found on the periphery of the bands.

Aging↗

PubMed1991

Relative legibility study using Chinese optotypes.

Traditionally, visual acuity test charts have been constructed using the English alphabet. It is desirable to have charts made in the native language of the Chinese and Asian populations. Previous efforts in this respect have not considered the relative legibility of Chinese optotypes. In this study, twelve Chinese optotypes were constructed according to the Snellen principle and subjected to a relative legibility trial. This study provides a basis on which Chinese optotypes of near-equal legibility may be selected.

Adolescent↗

PubMed1989

Immunologic changes in children with Henoch-Schonlein purpura in the acute stage.

T-lymphocyte subsets, B-lymphocyte, immunoglobulins and complement were studied in 38 children with Henoch Schonlein Purpura (HSP) in the acute stage. They had significantly lower CD3 percentage and lymphocyte blastogenesis rate, greater CD8 variation coefficient and B-lymphocyte percentage and higher levels immunoglobulins (IgA, IgG, IgM) and complement 3 than the controls. 21 (55%) of them had a low CD8 percentage. The results indicated that children with HSP had low T-lymphocyte percentages and function, increased B-lymphocyte percentage and function, high immunoglobulins, normal or elevated complement. On the other hand, no significant differences were found in the T-lymphocyte subsets values among healthy children aged 7-11 years. The normal values of T cell subsets in 35 normal controls were CD3 66-70%, CD4 37-41%, CD8 28-32%, respectively.

B-Lymphocytes↗

PubMedDate not supplied

Use of early tactile stimulation in rehabilitation of digital nerve injuries.

OBJECTIVE: Digital nerves are the most frequently injured peripheral nerve. To improve the recovery of functional sensibility of digital nerve injuries, a prospective randomized controlled study was conducted to see the effect of using early tactile stimulation in rehabilitation of digital nerve injuries. METHOD: Two specific tactile stimulators were made and prescribed for patients with digital nerve-injury. Twenty-four participants with 32 digital nerve injuries received the prescribed tactile stimulators (experimental group), and another 25 participants with 33 digital nerve injuries received only routine conventional therapy (control group). RESULTS: A significant difference (p < .05) was seen in the experimental group, although there were some variations between the different classes of associated injuries, with least benefit observed in the combined nerve, tendon, and bone injury class. CONCLUSION: Use of early tactile stimulation as described in this study can be considered an effective way to improve both quality and quantity of recovery of functional sensibility in digital nerve injuries without combined nerve, tendon, and bone injuries.

Adult↗