Search PubMed⌕ Search

Biomedical subjects

K S Cheng

Publications and source records attributed to K S Cheng.

At least 19 recordsLinked to original sources
PubMed2001

Anticonvulsive and free radical scavenging activities of Gastrodia elata Bl. in kainic acid-treated rats.

Gastrodia elata Bl. (GE) is a traditional Chinese herb that is commonly used in Chinese communities to treat convulsive disorders such as epilepsy. The purpose of the present study was to determine the anticonvulsive and free radical activities of GE in rats. In vitro studies were conducted by using brain tissue from 6 male Sprague-Dawley (SD) rats treated with 120 microg/ml of kainic acid (KA), with or without the addition of various concentrations of GE. In vivo studies were conducted in a total of 30 male SD rats divided into 5 groups of 6 rats which were treated as follows: 1) the normal group received an intraperitoneal injection (i.p.) of PBS (Phosphate buffer saline, 1 ml/kg); 2) the control group received KA (12 mg/kg) i.p.; 3) the GE 1.0 group received oral administration of GE 1.0 g/kg 30 min prior to KA administration; 4) the GE 0.5 group received oral administration of GE 0.5 g/kg 30 min prior to KA administration; 5) the PH group received oral administration of phenytoin 20 mg/kg 30 min prior to KA administration. Seizures were verified by behavioral observations, electroencephalograph (EEG) and electromyography (EMG). Lipid peroxide levels in the rat brain, luminol chemiluminescence (CL) and lucigenin-CL in the peripheral blood were measured simultaneously after behavioral observations. The results indicate that GE administration significantly reduced KA-induced lipid peroxide levels in vitro. Oral administration of GE 1.0 g/kg and phenytoin 20 mg/kg significantly reduced counts of wet dog shakes (WDS), paw tremor (PT) and facial myoclonia (FM) in KA-treated rats. In addition, oral administration of GE 1.0 g/kg significantly delayed the onset of WDS, from 30 min in the control group to 46 min in the 0.5 g/kg group, and 63 min in the GE 1.0 g/kg group. A significantly reduced level of lipid peroxides in the rat brain was found in the GE 1.0 g/kg, 0.5 g/kg, and phenytoin 20 mg/kg groups. The GE 1.0 g/kg group showed significant reduction of luminol-CL and lucigenin-CL counts in the peripheral blood compared to the control group. The results of the present study demonstrate that GE has anticonvulsive and free radical scavenging activities. Further studies are needed to determine the clinical effectiveness of GE as an anticonvulsant in humans.

Analysis of Variance↗
PubMed2001

Factors affecting the recovery of Legionella pneumophila serogroup 1 from cooling tower water systems.

A total of 20 water samples collected from the cooling towers at 20 different sites were analyzed under various conditions for the presence of Legionella pneumophila serogroup 1. A comparative assessment was performed to evaluate methods of sample collection (spray drops, beneath water at 20- to 40-cm depth, and water outlet), concentration (filtration and centrifugation), acid buffer treatment (no treatment, treatment for 3, 5, and 15 min), and CO2 incubation or candle jar incubation. The reduction in viable colonies and false negative rate were compared for the different factors. No quantitative differences in isolation of L. pneumophila serogroup 1 was found among samples collected from water at a depth of 20 to 40 cm, from water outlet, and from spray drops. Treatment in an acid buffer for 15 min significantly reduced the recovery rate, with a reduction in bacterial counts of about 40%, compared with a 3-min (12%) or a 5-min (25%) treatment. Acid buffer treatment for 3 or 5 min reduced the overgrowth of commensal flora. This treatment improved the selectivity but not the sensitivity for L. pneumophila serogroup 1. Colonies on plates incubated at 37 degrees C in a candle jar with a humidified atmosphere grew better than those incubated at 35 degrees C with 5% CO2. These results demonstrate that methods of sample collection, concentration, and incubation, but not collection site, can affect the isolation rate for L. pneumophila serogroup 1.

Air Conditioning↗
PubMed2000

Theoretical study of convergent ultrasound hyperthermia for treating bone tumors.

This study investigates the optimal external parameters for using an ultrasound applicator for treating bone tumors. This system utilized spherically arranged applicators such as scanned focused ultrasound, and spherically focused multielement applicators. The power deposition pattern is modeled as geometric gain with exponential attenuation. The specific absorption rate ratio (SARR) criteria have been used to determine the proper heating domain of ultrasound driving frequency and therapeutic tumor diameter. The results demonstrate that the optimal driving frequency depends on tumor depth, ultrasound absorption of bone marrow, and diameter of bone, but it is independent of the acoustic window area and SARR. The treatable diameter of bone tumor increased when the absorption ratio of bone marrow to tumor, acoustic window of surface skin, and diameter of bone were elevated. However, the treatable diameter of bone tumor decreased when muscle thickness, SARR of bone tumor site to the surface skin, bone marrow, and bone declined. To deliver the ultrasound energy into the tumor site and to avoid the potential damage to the normal tissue as much as possible, the specific absorption rate (SAR) in the bone tumor site has to be three times higher than that in the surface skin, tumor/marrow, and marrow/bone interfaces. The temperature distributions can verify the SARR criteria in this model. This study provides the information for choosing the optimal operating frequency of the ultrasound transducer and the acoustic window on the skin surface, and for designing the ultrasound applicator for clinical implementation.

Biomedical Engineering↗
PubMed2000

Accuracy of computerized automatic identification of cephalometric landmarks.

Computerized cephalometric analysis can include both landmark identification and determination of linear or angular measurements. Although its use is time saving compared with a manual method, the accuracy of automatic landmark identification remains unclear. The purpose of this study was to evaluate the accuracy of a computerized automatic landmark identification system that used an edge-based technique. The technique divides the scanned cephalogram into 8 rectangular subimage regions. After the resolution of these subimages is reduced, the edges are detected and the landmarks are located automatically. Thirteen landmarks were selected for assessment on a set of 10 test cephalograms. The results showed that the errors between manual and computerized identification for landmarks were not significantly different (P > .05) for 5 of 13 landmarks: sella, nasion, porion, orbitale, and gnathion. These results suggest that the accuracy of computerized automatic identification is acceptable for certain landmarks only. Further studies to improve the accuracy of computerized automated landmark identification are needed.

Cephalometry↗
PubMed2000

Genetic analysis and clinical evaluation of vacuolating cytotoxin gene A and cytotoxin-associated gene A in Taiwanese Helicobacter pylori isolates from peptic ulcer patients.

The aims of this study were to investigate the cytotoxin-associated gene A (cagA) and vacuolating cytotoxin gene A (vacA) subtype in Taiwanese H. pylori isolates from patients with gastroduodenal diseases and to assess the relationship between genotypes of isolates and clinical features. The vacA s1a allele was found in all isolates and vacA m1 allele was found in 15% of isolates. The cagA gene was found in 82.5% of isolates. The vacA s1a/m2 strains had a significantly higher prevalence rate than vacA s1a/m1 strains in Taiwan (p < 0.05). By aligning and comparing the nucleotide and amino acid sequences of vacA from the Taiwanese isolates, the signal sequence and N-terminal region were found to be highly conserved, but the middle region was found to be highly heterogeneous. Determining the relationship between the genotypes and clinical features, we found that the cagA gene was more closely associated with duodenal ulcer than with gastric ulcer and the vacA s1a/m2 strain was more closely associated with active chronic gastritis and atrophic gastritis than with chronic gastritis. Together, our results indicated that (i) the middle region of vacA gene in Taiwanese isolates was heterogeneous; (ii) s1a/m2 vacA strains had a high prevalence in Taiwanese peptic ulcers; and (iii) the cagA gene was significantly associated with duodenal ulcer.

Acute Disease↗
PubMed2000

Expression of proliferating cell nuclear antigen in luminal epithelium during the growth and regression of rat uterus.

Proliferating cell nuclear antigen (PCNA), a processivity factor of DNA synthesis, has often been used as a marker that reveals proliferating cells. However, it also plays a role other than in DNA replication. The aim of this study was to examine the relationship between the expression of PCNA and cell proliferation, and also its relation to cell death in the uterine epithelium under various hormonal conditions. Rats with regular estrous cycles were killed at various stages of the cycle, and their uteri were removed for the detection of PCNA and apoptosis by immunohistochemical and terminal deoxynucleotidyl transferase-mediated nick end-label staining respectively. There was an inverse relationship between the expression of PCNA and apoptosis in the uterine epithelium during the estrous cycle. From diestrus to proestrus, the expression of PCNA increased, and few apoptotic cells were detected in the luminal epithelium. However, at estrus, apoptosis occurred markedly, and the expression of PCNA disappeared. To study further the effects of estrogen on PCNA expression and cell growth in the uterus, rats were ovariectomized and then implanted s.c. with estrogen capsules 2 weeks later. In ovariectomized rats, only a few PCNA-positive cells were observed in the uterine epithelium. After estrogen treatment, PCNA was expressed strongly in the luminal and glandular epithelia. In these rats, the removal of estrogen capsules resulted in apoptotic death and surprisingly strong PCNA expression in the cells of luminal epithelium. Our results demonstrate that PCNA is expressed not only in the estrogen-stimulated uterine growth, but also in the processes of regression induced by the withdrawal of estrogen. Although the expression of PCNA has been reported to represent cell proliferation, our results implicate functions other than cell replication for PCNA in the uterus.

Animals↗
PubMed2000

Cost-effective approach of video-assisted thoracic surgery: 7 years experience.

BACKGROUND: Cost containment is the driving force behind current health care reform. While video-assisted thoracic surgery (VATS) permits a less invasive approach to surgical diseases of the chest, cost is one aspect that is seldom discussed. In Asia, cost-effectiveness essential for the survival of this approach. We present our cost-effective experience with VATS in 2300 patients over a 7-year period. METHOD: Between 1992 and 1999, 2300 patients underwent video-assisted thoracic surgery at Chang Gung Memorial Hospital. The mean age was 53.2 years (range, 22 days to 102 years); 67% (1541 patients) were men. The VATS technique was mainly performed based on traditional surgical principles. Conventional instruments and the fundamental surgical techniques of dissection, suturing, hemostasis, and tissue approximation that are familiar in the open setting were modified and used to enhance cost savings during VATS. RESULTS: Surgery was performed on 41 patients on an emergency basis (24 with impending cardiac tamponade and 17 with hemothorax). The mean hospital stay of the patients treated by VATS was 4.5 days. The majority of the patients were operated on successfully using conventional instruments under video vision. The overall operative cost was decreased as compared to common VATS techniques. No delayed morbidity was noted in our patients after a mean follow-up period of 39 months (range, 1 to 68 months). CONCLUSION: It is our experience that VATS procedures should be performed with the same expertise as open surgery. Conventional instruments similar to those used in open thoracotomy can be incorporated in VATS, and with a more natural hand manipulation. Only through stringent use of expensive endoscopic consumables and application of modified techniques based on traditional surgical principles can VATS be performed efficaciously and economically for a wide range of thoracic conditions.

Adolescent↗
PubMed2000

Propofol-sodium thiopental admixture reduces pain on injection.

BACKGROUND: Propofol injection associated with a high incidence of pain is well known. Propofol and sodium thiopental mixture has recently been reported to be used for cost saving and able to reduce pain on injection. METHODS: This prospective, randomized, double blind trial was designed to compare the efficacy of different percentages of propofol and sodium thiopental mixture in minimizing propofol injection pain. 146 ASA class 1 patients were assigned to seven groups (pure propofol, pure sodium thiopental, and propofol premixed with 10%, 20%, 30%, 40%, and 50% of sodium thiopental). The intensity of pain was graded and recorded as severe, moderate, mild and no pain according to the response of the patients to the injection. RESULTS: The intensity of injection pain was significantly greater for pure propofol than the others while it was not significantly different among the other groups in comparison. CONCLUSIONS: Sodium thiopental, when added to propofol, can significantly reduce propofol injection pain. This attenuation effect was noted even with as low as 10 volume % of sodium thiopental.

Adult↗
PubMed1999

Emphysema surgery--loop ligation approach.

OBJECTIVES: To demonstrate the efficacy of using thoracoscopic endoloop ligation of bullae in patients with bullous emphysema. METHODS: From 1992 to 1997, 93 advanced age (mean age, 66 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Thoracoscopic loop ligation of bulla was carried out under general anesthesia with double lumen endotracheal tube and single lung ventilation. RESULTS: Eighty-two patients (88%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 7.5 days (range, 4-19 days). Average hospital stay was 9.5 (range, 5-26) days. There was no post-operative death. A comparison of pre-operative and post-operative functional evaluation was available in 27 patients who showed an average increase in FEV1 (from 0.89 to 1.12 l) and declined in residual volume after operation. Complications include persistent airleak over 10 days in nine patients (9.7%), wound infection in three patients and localized empyema in five patients. There was no recurrent after a mean follow-up of 37 months. CONCLUSION: Thoracoscopic loop ligation of bulla has proven to be a safe, reliable and cost effective means of technique for bullous emphysema.

Aged↗
PubMed1999

Epiglottic hematoma secondary to endotracheal intubation.

Though trauma related to direct laryngoscopy may occur anywhere from the lips to the glottis, damage to the epiglottis during intubation is a rare complication. Although large hematoma formation in the epiglottis after intubation is uncommon, its nature is potentially lethal. We report a case of epiglottic hematoma secondary to endotracheal intubation.

Adult↗
PubMed1999

Comparison of nasal trauma associated with nasopharyngeal airway applied by nurses and experienced anesthesiologists.

BACKGROUND: Insertion of a nasopharyngeal airway by nurses is considered to be invasive. We compared the incidence and severity of nasal injury associated with nasopharyngeal airway insertion by trained nurses to those by anesthesiologists to determine the safety of inserting a nasopharyngeal airway by nurses in cardiopulmonary resuscitation (CPR). METHODS: One hundred and sixteen male and 96 female patients scheduled for general anesthesia were included in the study. The male and female patients were randomly assigned to two groups respectively. Anesthesia was induced with sodium thiopental and fentanyl intravenously. The patients were then ventilated with a bag-valve-mask by trained nurses or anesthesiologists. In the unsuccessfully ventilated patients, nasopharyngeal airways were inserted to facilitate subsequent ventilation. The nasopharyngeal airway, oropharynx, and nostrils were then examined. The incidence and severity of nasal trauma induced by trained nurses or by anesthesiologists were compared. RESULTS: The study revealed that nasopharyngeal airways applied by trained nurses did not induce more severe nasal trauma than those by anesthesiologists. CONCLUSION: We suggest that nasopharyngeal airways may be applied safely by trained nurses in CPR.

Adult↗
PubMed1998

Characterization of the relationship between motor end-plate jitter and the safety factor.

A mathematical model developed for a personal computer was used to simulate the jitter phenomenon in neuromuscular transmission in order to characterize the relationship between jitter and the safety factor. Four models of normal and abnormal neuromuscular transmission were investigated. In a human experiment, the mean consecutive difference (MCD) values for stimulated single-fiber electromyography at firing rates of 1, 2, 5, and 10 Hz were measured in 137 motor end-plates of myasthenic patients. Results of the computer simulations show that the relationship between jitter and the safety factor is exponential like. Variations in jitter are most prominent in end-plates with low safety factors. This relationship agrees with results of human end-plate studies. Changes in the MCD values caused by presynaptic depression or facilitation are linearly correlated to the initial jitter, whereas the logarithmic values of MCD are not. It is very important to keep in mind this nonlinear relationship when relating single-fiber jitter to the safety factor.

Computer Simulation↗
PubMed1998

Expression of fibroblast growth factor-1 and fibroblast growth factor-2 in normal liver and hepatocellular carcinoma.

This study was performed to examine the immunohistochemical expression of fibroblast growth factor-1 and fibroblast growth factor-2 in normal liver and a total of 31 cases of hepatocellular carcinoma (HCC). Reactivity for both types of angiogenic factor did not exist in any cellular component of normal liver. For HCC, variable amounts of fibroblast growth factor-1 were detected in 6 of 31 cases (19.4%). There was no apparent relationship between the expression pattern and clinicopathologic factors (P > 0.1, respectively), except a positive correlation with histologic grading (P = 0.04). No tumor showed reactivity for fibroblast growth factor-2 in their cancer cells. However, both types of peptide could be demonstrated in the pericellular stroma of HCC. With a mean follow-up at 60 months, fibroblast growth factor-1 expression did not correlate with patients' outcome (P > 0.1). Our study suggested that fibroblast growth factor-1 appears to play a certain role in hepatocarcinogenesis.

Adolescent↗
PubMed1998

Incidental computed tomography diagnosis of a giant oesophageal leiomyosarcoma.

Leiomyosarcoma of the oesophagus is a very unusual tumour; only 53 cases have been reported in the English-language literature. A case is reported here of a patient with a giant leiomyosarcoma, without any symptoms of dysphagia. The diagnosis was made incidentally during CT examination of the chest for detection of possible pulmonary metastases from a coexisting carcinoma of the bladder. This was confirmed by a barium swallow, oesophagoscopy and tissue diagnosis. The literature pertaining to this most uncommon tumour is reviewed.

Aged↗