A modified endotracheal tube for infants and small children undergoing video-assisted thoracoscopic surgery.
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Auscultation↗
Biomedical subjects
K S Cheng
Publications and source records attributed to K S Cheng.
Displacement of double-lumen tubes after patient positioning.
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Bronchoscopy↗
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↗
Specific absorption rate ratio patterns of cylindrical ultrasound transducers for breast tumors.
The purpose of this paper is to examine the optimal driving frequency and to configure the ultrasound energy deposition schema for a various size and location of breast tissues when a portion or the entire cylindrical ultrasound transducer is employed for breast hyperthermia treatments. This work employs a computer simulation program based on an ideal ultrasound power deposition from a cylindrical transducer. The ultrasound power within the breast is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam and a uniform absorption for the entire breast is also assumed. The distribution of the specific absorption rate (SAR) ratio is employed to determine the heating pattern of a set of given parameters. The control parameters considered are the ultrasound frequency in the breast tissue, the active portion of cylindrical transducer, and the shifting distance between the central axes of the breast and the transducer. The effect of the breast size on the SAR ratio is also considered. Simulation results demonstrate that the breast size, the ultrasound frequency in breast tissue, the shifting distance, and the active portion of the cylindrical transducer are the potential parameters for influencing the distribution of the SAR ratio. High frequencies should be used for the superficial heating treatments and the active portion of the transducer can be changed to obtain a region with an appropriate SAR ratio to cover the treatment region. Low frequencies are used for deep heating treatments and the region of the high SAR ratio can be moved by shifting the transducer and its pattern is varied with the transducer's active portion. The distribution of the SAR ratio indicates the domain of treatable tumor size and tumor depth for a given set of parameters (driving frequency, shifting distance and active portion of the transducer, as well as breast diameter). Findings of this study can be used to know whether or not the tumor is treatable as well as to select the optimal driving frequency and the appropriate active portion of the cylindrical transducer for a treatment, and hopefully to design an appropriate cylindrical ultrasound heating system for breast tumors.
Biophysical Phenomena↗
Helicobacter pylori in gastric biopsies of Taiwanese patients with gastroduodenal diseases.
This study was designed to study the in vivo prevalence and the heterogeneity of H. pylori in patients with gastroduodenal diseases in central Taiwan. H. pylori infection was detected in 74.1% (575/776) of the symptomatic population studied. The prevalence of H. pylori infection increased from 11.1% in those between the ages of one to 20, to 82.9% in those between the ages of 41 and 50, and to 84% in those between the ages of 51 and 60. There was no significant difference in the prevalence of H. pylori infection between men and women. Among different blood types, the prevalence and relative risk of H. pylori infection was significantly higher in blood group O patients (90.3%) than in blood group A (41%), blood group B (27.4%), or blood group AB (62%) patients. Metronidazole resistance was found in 6.7% of the primary isolates. The prevalence of metronidazole-resistant H. pylori strains was higher in women (7.69%) than in men (6.25%), but this difference was not significant. A total of 88% of H. pylori strains were cagA-positive. CagA gene-positive strains were present in 90.1% of duodenal ulcers, 90% of duodenal ulcers combined with gastric ulcer, 85.8% of gastric ulcers, and 69.2% of gastritis patients, and was significantly higher in peptic ulcer disease groups than in the gastritis group. In conclusion, there was a low incidence (6.7%) of metronidazole-resistant H. pylori strains and a high prevalence (88%) of H. pylori cagA-positive strains in central Taiwan. This study also demonstrated a significant in vivo correlation between active H. pylori infection and blood group O-positive patients, and showed a significant association between cagA gene-positive H. pylori strains and the development of peptic ulcers.
ABO Blood-Group System↗
Incidence and clinical manifestations of Campylobacter enteritis in central Taiwan.
BACKGROUND: Campylobacter species are recognized as a major cause of acute gastroenteritis in humans throughout the world and are increasingly associated with the development of Guillain-Barré syndrome. The age distribution of persons and the seasonal patterns of Campylobacter infection are different in many developed and developing countries. The present study reports the investigation of the clinical and epidemiologic features of Campylobacter infections in central Taiwan. METHODS: From January 1994 to December 1996, stool specimens from patients with diarrhea or gastroenteritis were cultured for the Campylobacter species at the China Medical College Hospital. Data collected and evaluated included the type of Campylobacter species isolated, date of report, age and sex of the person from whom the isolate came, and clinical symptoms. RESULTS: Of 6,540 patients with diarrhea or gastroenteritis, 162 Campylobacter isolates were identified, yielding an isolation rate of 2.5% from the population studied. One hundred and fifty-four patients (95%) with Campylobacter infection were younger than five years old, which was significantly different from the population studied (p < 0.001). The Campylobacter infection was significantly higher in males (62.3%) than females (37.7%) (p = 0.0017). In central Taiwan, the incidence of Campylobacter enteritis is higher during the winter (35.2%) than during the spring (19.1%), summer (24.1%) or fall (21.6%) (35.2 vs 24.1%, p = 0.021). Campylobacter jejuni was found to comprise 81% (132 strains) of 162 Campylobacter isolates, and its isolation rate was significantly higher than Campylobacter lari (10%) and Campylobacter coli (9%) (p < 0.001). From 1994 to 1996, isolation rates of Campylobacter species increased from 1.9 to 2.8% of the population studied (34/1, 754 vs 57/2, 187) and the positive isolation rate ratio of Campylobacter species to Salmonella species also increased from 15.4 to 27.8% (34/221 vs 57/205). However, no significant difference was found between these results (p > 0.05). Watery diarrhea is the most characteristic manifestation of illness, and fever occurs in more than half of the patients. CONCLUSIONS: In central Taiwan, the incidence of Campylobacter enteritis in patients with diarrhea or gastroenteritis is lower than those in China and Tanzania, but the highest prevalence occurs before five years of age in central Taiwan as well as these countries. The Campylobacter infection rate was significantly higher in males than females, and occurred primarily in winter. We conclude that Campylobacter cultures should be performed for fecal specimens of all diarrheal children aged up to five years.
Adolescent↗
Characterization of arylamine N-acetyltransferase in Enterobacter aerogenes.
N-acetyltransferase (NAT) activity was determined by incubation of purified Enterobacter aerogenes enzyme with 2-aminofluorene (2-AF) as the substrate, followed by high pressure liquid chromatography assays. The NAT activity from E. aerogenes was 0.58 +/- 0.08 nmol/min/mg protein for 2-AF. The values of apparent K(m) and Vmax were 0.72 +/- 0.14 mM and 2.45 +/- 0.29 nmol/min/mg protein, respectively, for 2-AF. The optimal pH value for the enzyme activity was 7.5 for the 2-AF tested. The optimal temperature for enzyme activity was 37 degrees C for the 2-AF substrate. The molecular weight of NAT from E. aerogenes was 44.9 kD. Among a series of divalent cations and salts, Zn2+, Ca2+, and Fe2+ were demonstrated to be the most potent protease inhibitors, and only ethylenediaminetetraacetic acid significantly protected the NAT. Iodoacetamide, in contrast to other agents, markedly inhibited NAT.
Arylamine N-Acetyltransferase↗
Expression of vascular endothelial growth factor in normal liver and hepatocellular carcinoma: an immunohistochemical study.
Angiogenesis is of vital importance during the development and progression of solid tumors. To examine the role of vascular endothelial growth factor (VEGF) in hepatocarcinogenesis, we evaluated the expression of peptide in normal human liver (n = 6) and in 36 cases of hepatocellular carcinoma (HCC). Immunoreactivity for VEGF was present in the extracellular matrix of the portal tracts in the normal and nontumor part of liver, but not in hepatocytes and bile duct epithelium. For HCC, variable amounts of VEGF were expressed in 13 cases (36.1%) of tumor cells. Using a logistic regression model, expression of VEGF was significantly associated with a higher proliferative index (P = .01) and sonographic portal vein thrombosis (P = .05). However, VEGF expression did not correlate with a biochemical liver profile, alpha-fetoprotein levels, histological grading, gender, or clinical stage of cirrhosis (P > 0.1, respectively). Log-rank test showed that evaluation of VEGF did not provide more prognostic information (P > .5) than that from tumor volume and portal vein thrombosis (P < .01, respectively). In addition, VEGF was always present in the fibrovascular stroma or pericellular matrix of HCC, although no strong relationship was observed with the expression of VEGF in tumor cells (P > .5). Our data suggested that expression of VEGF may characterize a progression toward higher proliferation in hepatocarcinogenesis in vivo. The relevance of VEGF existing in the extracellular matrix of the normal liver and HCC remains to be clarified.
Adolescent↗
Prevalence and heterogeneity of Helicobacter pylori in gastric biopsies of patients with gastroduodenal diseases.
Helicobacter pylori is a risk factor for development of peptic ulcers and adenocarcinoma of distal stomach. There are several highly specialized virulence factors, such as the production of sialic acid-specific hemagglutinins, cytotoxins and enzymes. This study was designed to study the in vivo prevalence of H. pylori in patients with gastroduodenal diseases, the in vivo correlation between H. pylori infection and blood group O, and the heterogeneity of H. pylori isolates in central Taiwan. We enrolled 776 symptomatic patients residing in the central Taiwan area. The age-specific in vivo prevalence of H. pylori in patients with gastroduodenal diseases increased from 11.1% in those between the ages of 1 to 20, 73.1% in those between the ages of 21 and 30, and to 79.8% in those between the ages of 51 and 60. In conclusion, H. pylori was present in 70% of biopsied specimens of symptomatic patients with gastroduodenal diseases and had the highest incidence (86%) in patients with peptic ulcers. The prevalence of H. pylori cag A expression positive strains in central Taiwan was 92.5%. This study has also demonstrated the high correlation between H. pylori and the blood group O-positive patients with gastroduodenal diseases. The prevalence of H. pylori infection in blood O-positive patients in central Taiwan was 86.4%.
ABO Blood-Group System↗
Evaluation of CLO test and polymerase chain reaction for biopsy-dependent diagnosis of Helicobacter pylori infection.
Helicobacter pylori is now recognized as possibly playing an etiologic role on the development of chronic gastritis, peptic ulcers and adenocarcinoma of the distal stomach. CLO test and polymerase chain reaction (PCR) assay are rapid, biopsy-dependent diagnostic tests for H. pylori identification. In this study, we assessed four diagnostic methods (CLO test, PCR assay, culture and histological examination) for H. pylori detection in biopsy specimens from 78 patients with gastroduodenal diseases and investigating the efficiency of CLO test and PCR assay for the diagnosis of H. pylori infection. H. pylori was identified in 75.6%, 75.6%, 64.1%, 69.2% of patients by CLO test, PCR assay, culture and histological examination, respectively. Compared with the detection of H. pylori by culture and/or histological examination, the sensitivity and specificity of the CLO test were 98.2% and 81.8%, respectively, whereas the sensitivity and specificity of PCR assay were 96.4% and 77.3%, respectively. According to the H. pylori infection state as determined from the results of three concordant tests, the sensitivities of culture, CLO test, histological examination, and PCR assay were 90.9%, 96.4%, 98.2% and 100%, respectively. Whereas, the specificity was 100%, 95%, 95% and 90% for culture, CLO test, histological examination, and PCR assay, respectively. We found that both CLO test and PCR assay were highly sensitive and specific for H. pylori identification; however, PCR assay was more sensitive than other methods for detecting the specimens after patients received treatment. The results of this study suggest that CLO test is a rapid and sensitive method of screening for H. pylori infection and that PCR assay could provide an accurate indication of the state of infection both during treatment for eradication of H. pylori and at follow-up.
Biopsy↗
High frequency jet ventilation for severe pulmonary hemorrhage during aortic dissection operation--a case report.
Massive endobronchial bleeding during extracorporeal circulation was encountered in a patient during aortic dissection operation. The use of high frequency jet ventilation resulted in successful staunching of the bleeding, thus avoiding the need of pneumonectomy or lobectomy.
Aortic Dissection↗
Segmentation of multispectral magnetic resonance image using penalized fuzzy competitive learning network.
Segmentation (tissue classification) of the medical images obtained from Magnetic resonance (MR) images is a primary step in most applications of computer vision to medical image analysis. This paper describes a penalized fuzzy competitive learning network designed to segment multispectral MR spin echo images. The proposed approach is a new unsupervised and winner-takes-all scheme based on a neural network using the penalized fuzzy clustering technique. Its implementation consists of the combination of a competitive learning network and penalized fuzzy clustering methods in order to make parallel implementation feasible. The penalized fuzzy competitive learning network could provide an acceptable result for medical image segmentation in parallel processing using the hardware implementation. The experimental results show that a promising solution can be obtained using the penalized fuzzy competitive learning neural network based on least squares criteria.
Adult↗
Multispectral magnetic resonance images segmentation using fuzzy Hopfield neural network.
This paper demonstrates a fuzzy Hopfield neural network for segmenting multispectral MR brain images. The proposed approach is a new unsupervised 2-D Hopfield neural network based upon the fuzzy clustering technique. Its implementation consists of the combination of 2-D Hopfield neural network and fuzzy c-means clustering algorithm in order to make parallel implementation for segmenting multispectral MR brain images feasible. For generating feasible results, a fuzzy c-means clustering strategy is included in the Hopfield neural network to eliminate the need for finding weighting factors in the energy function which is formulated and based on a basic concept commonly used in pattern classification, called the 'within-class scatter matrix' principle. The suggested fuzzy c-means clustering strategy has also been proven to be convergent and to allow the network to learn more effectively than the conventional Hopfield neural network. The experimental results show that a near optimal solution can be obtained using the fuzzy Hopfield neural network based on the within-class scatter matrix.
Algorithms↗
Recurrent panniculitis as the first clinical manifestation of recurrent acute pancreatitis secondary to cholelithiasis.
A case of recurrent panniculitis in the legs as the first clinical manifestation of recurrent acute pancreatitis secondary to cholelithiasis is described in a 59-year-old Caucasian woman.
Acute Disease↗
Double-lumen endotracheal tube intubation in difficult intubation-use the WuScope System: a case report.
Although not an absolute requirement in most cases, there are many anesthetic and surgical advantages for using a double-lumen tube during intrathoracic operations. It is almost impossible that double-lumen tube intubation by conventional methods in patients whose glottis can not be visualized by direct laryngoscopy. We describe the previously unreported method by using The WuScope System for double-lumen endotracheal tube intubation in a patient with acromegaly and difficult airway.
Female↗
[The incidence of double-lumen tubes displacement after positioning of patients during anesthesia].
BACKGROUND: Although many reports have described that unexpected displacement of double-lumen endobronchial tube (DLT) may be caused by patient positioning, however, in Taiwan the matter has not been reported, nor its incidence has been determined. The purpose of this study was to determine the incidence of DLT displacement after patient positioning. METHODS: Eighty patients undergoing elective thoracotomy that required an anesthesia with the use of left DLT were studied. An Olympus LF-P broncho-fiberscope was used to estimate the distance between the carina and the distal end of the DLT via the tracheal lumen before and after patient positioning. RESULTS: All DLT were confirmed to be in the correct position in eighty patients before patient positioning. After patient positioning, the DLT moved proximally 1.5 cm, 1 cm and 0.5 cm in eighteen (22.5%), sixteen (20%) and eight (10%) patients respectively. In nine patients (11.25%) DLT displacement after positioning resulted in a failure to ventilate the lungs separately and required readjustment of the DLT. CONCLUSIONS: Our result suggests that there is a high incidence of DLT displacement during patient positioning. Whenever the patient is repositioned, we recommend that constant vigilance is necessary to guard against tube displacement. Attention should be focused on possible causative factors so that the incidence can be decreased and the safety of DLT application assured.
Anesthesia↗
Radiological imaging of a massive dermoid in the male pelvis.
A dermoid cyst, arising from the posterior aspects of the prostate and seminal vesicles, and extending into the pelvis to masquerade as a full bladder, must be exceedingly rare. Ultrasound, computed tomography and especially magnetic resonance imaging (MRI) proved to be invaluable in making the diagnosis, and MRI in particular was very useful in providing an anatomical road map for surgery.
Adult↗
Gastrointestinal bleeding due to whipworm (Trichuris trichiura) infestation: a case report.
Severe whipworm infestation, an exceedingly uncommon cause of gastrointestinal bleeding, has not been reported in Taiwan. The reported case concerns a 59-year-old female who had suffered from abdominal pain and passage of tarry stool for several days. Esophagogastroduodenoscopy was performed, and several roundworms were seen in the second portion of duodenum. After removal, the characteristic appearance of Trichuris trichiura was apparent. After exploratory laparotomy for intractable bloody stool, the result of operative findings and pathological reports also confirmed our diagnosis. This is a case presented of massive gastrointestinal bleeding in which the cause of bleeding was diagnosed before operation to be whipworm infestation by endoscopic examination. The clinical and pathologic characteristics of the trichuriasis are described, with a brief review and discussion.
Female↗