Biomedical subjects

Chung-Ming Chen

Publications and source records attributed to Chung-Ming Chen.

At least 19 recordsLinked to original sources

PubMed2007

Continuous intraarterial infusion chemotherapy for early lip cancer.

Most lip cancers are usually diagnosed and can be treated with good prognosis at an early stage. This study reports our experience of treating seven, previously untreated, patients with lip cancer in stage I or II using intraarterial infusion chemotherapy with a single agent. They were all males with ages ranging from 37 to 69 years. An implantable port-catheter system was used for catheterization. Methotrexate 50mg was infused continuously to the external carotid artery every 24h using a portable pump. Methotrexate was given continuously for a mean period of 7 days (range, 4-10 days) and the total administrated dose of methotrexate for intraarterial infusion ranged from 200 to 500 mg (mean, 350 mg). These seven patients were then given weekly bolus of methotrexate (25mg) via intraarterial route for a range of 6-12 weeks. In every case the tumor regressed dramatically and disappeared completely after treatment within a mean period of 2.5 months. Only one patient died, of non-disease related pneumonia 3 years after infusion therapy. The remaining patients are still alive and no recurrence of carcinoma has been observed at a median follow-up period of 28 months. There was no catheter-related complication. The side effects of infusion chemotherapy were mild and tolerable. Our technique of continuous intraarterial infusion therapy for treatment of early lip cancers seems to be as effective as other standard techniques such as surgery or radiation therapy. This modality achieves good tumor response rates, an excellent cosmetic result, preservation of function and minimal side effects.

Adult↗

PubMed2006

Which octogenarians do poorly after major open abdominal surgery in our Asian population?

BACKGROUND: As the elderly population grows and surgeons are faced with more octogenarians, there is a need to know how our Asian patients fair after major surgery. METHODS: A retrospective review of 125 octogenarians who underwent major abdominal surgery between January 1997 and September 2003 was performed. Preoperative condition was assessed using a weighted index of comorbidity used in Charlson Comorbidity Index and classification of patients according to the American Society of Anaesthesiologists (ASA). Outcome was measured as to whether complications developed, 30-day mortality and whether there was return to premorbid function. RESULTS: The patients had a mean age of 84.6 years (range: 80-106). Nearly half (48.8%, n = 61) the cases were emergency cases. The median index of comorbidity was 3, and 29.6% of patients were classified either ASA III or IV. The operations were mostly stomach, small bowel or large bowel resection. Multivariate analysis revealed that emergency operations were associated with significantly increased odds of morbidity. The overall 30-day mortality was 5.6%, being only 4.7% for elective cases, despite high morbidity rates. ASA classification, comorbidity index >5, development of acute coronary syndrome and anastomotic leakage were found on multivariate analysis to significantly increase the odds of mortality. For elective cases, 82.8% of patients were able to return to their premorbid functional status. Development of complications and comorbidity index >5 were found to predict failure of its occurrence. Low serum albumin and haemoglobin and renal impairment were also predictors of adverse outcome. CONCLUSIONS: Efforts to improve outcome in geriatric surgery patients should emphasize a shift of attitude towards elective surgery rather than doing emergency operations when complications occur and also target the optimization of predictors of adverse outcome. Octogenarians should not be denied elective surgery.

Abdomen↗

PubMed2005

Computational analysis and refinement of sequence structure on chromosome 22q11.2 region: application to the development of quantitative real-time PCR assay for clinical diagnosis.

The low-copy repeat (LCR) is a new class of repetitive DNA element and has been implicated in many human disorders, including DiGeorge/velocardiofacial syndrome (DGS/VCFS). It is now recognized that nonallelic homologous recombination (NAHR) through LCRs flanking the chromosome 22q11.2 region leads to genome rearrangements and results in the DGS/VCFS. To refine the structure and content of chromosome 22q11.2 LCRs, we applied computational analysis to dissect region-specific LCRs using publicly available sequences. Nine distinct duplicons between 1.6 and 65 kb long and sharing >95% sequence identity were identified. The presence of these sequence motifs supports the NAHR mechanism. Further sequence analysis suggested that the previously defined 3-Mb deletion may actually comprise two deletion intervals of similar size close to each other and thus indistinguishable when using fluorescence in situ hybridization (FISH) analysis. The differentially deleted regions contain several hypothetical proteins and UniGene clusters and may partially explain the clinical heterogeneity observed in DGS/VCFS patients with the 3-Mb common deletion. To implement further sequence information in molecular medicine, we designed a real-time quantitative PCR assay and validated the method in 122 patients with suspected DGS/VCFS. The assay detected 28 patients with chromosome 22q11.2 deletion later confirmed using FISH. Our results indicated that the developed assay is reliable as well as time and cost effective for clinical diagnosis of chromosome 22q11.2 deletion. They also suggest that this methodology can be applied to develop a molecular approach for clinical detection and diagnosis of other genomic disorders.

Chromosomes, Human, Pair 22↗

PubMed2005

Transforming growth factor-beta1 upregulation is independent of angiotensin in paraquat-induced lung fibrosis.

Transforming growth factor-beta1 (TGF-beta1) contributes to the fibrosis of injured organs. Angiotensin II (Ang II) is an inducer of TGF-beta1 in cells of the heart and kidneys, and the regulation of TGF-beta1 by Ang II has not yet been confirmed in lung tissue. We evaluated the role of TGF-beta1 and its relationship with Ang II in paraquat-induced lung fibrosis. Adult male Sprague-Dawley rats were treated intraperitoneally with paraquat (20mg/kg) or saline in the control group. On days 1, 3, 7, and 21 after paraquat treatment, TGF-beta1 and collagen gene expressions, TGF-beta1 protein, angiotensin-converting enzyme (ACE) activity, Ang II, and hydroxyproline contents were measured in lung tissue. Lung TGF-beta1 mRNA expression progressively increased and reached a peak on day 7 after paraquat treatment. Increases in TGF-beta1 mRNA expression and TGF-beta1 levels preceded the onset of increased collagen I mRNA expression and hydroxyproline contents. c-myc mRNA expressions were inversely correlated with TGF-beta1 protein levels in paraquat-treated lungs. Lung ACE activity decreased after paraquat administration and the decrement was maximal on day 7. Lung Ang II concentrations immediately decreased after paraquat administration and the values were not related to TGF-beta1 levels. We conclude that TGF-beta1 is upregulated and contribute to the paraquat-induced lung fibrosis and this effect is independent of the renin-angiotensin system.

Actins↗

PubMed2005

Effects of maternal nicotine exposure on lung surfactant system in rats.

Maternal smoking during pregnancy may impair pulmonary function in infants and children, but the exact mechanisms underlying these changes remain to be determined. Timed pregnant Sprague-Dawley rats were injected subcutaneously with nicotine at a dose of 2 mg/kg/day from days 3-21 of gestation. A control group was injected with saline. Nicotine-treated dams had lower body weights than control dams from gestational days 5-21, and the values reached statistical significance on gestational days 17, 20, and 21. Total lung saturated phosphatidylcholine contents tended to be lower in nicotine-exposed rats than in control rats from postnatal day 21, and the values reached statistical significance on postnatal days 35 and 42. Maternal nicotine exposure significantly increased surfactant protein (SP)-A, SP-B, SP-C, and SP-D mRNA expression on postnatal day 7, and decreased SP-A, SP-B, SP-C, and SP-D mRNA expression on postnatal day 14. In conclusion, maternal nicotine exposure during pregnancy reduces lung surfactant lipids and produces variable changes in surfactant protein gene expression during the late postnatal period. As good surface activity of pulmonary surfactant is essential for normal lung function, these results suggest that derangement of the pulmonary surfactant system may be important in the pathogenesis of impaired pulmonary function in children exposed in utero to nicotine.

Animals↗

PubMed2005

Interpretation of magnetic resonance imaging for locally advanced rectal carcinoma after preoperative chemoradiation therapy.

PURPOSE: Neoadjuvant concomitant chemoradiotherapy has been used in cases of locally advanced rectal cancer to preserve sphincter function, decrease local recurrence, and improve survival. Preoperative staging is essential for planning and providing optimal therapy. The purpose of this study is to determine the accuracy of staging with magnetic resonance imaging and to define any factors that interfere in interpretation of images obtained after preoperative chemoradiation therapy. METHODS: Thirty-six patients with biopsy-proven, locally advanced rectal cancer were treated with preoperative concomitant 5-fluorouracil-based chemotherapy and radiation, followed six to eight weeks later by radical surgery. Preoperative magnetic resonance images were reinterpreted by one radiologist and the results compared with histopathologic staging. RESULTS: T-level downstaging occurred in 10 of 36 patients (28 percent), and N-level downstaging occurred in 29 of 36 patients (80 percent) after completion of chemoradiation therapy. Pathologic complete remission after chemoradiotherapy occurred in five patients (12 percent). Of the 36 patients, 17 (47 percent) were overstaged and 2 (6 percent) were understaged in T-level, whereas 10 patients (28 percent) were overstaged and 3 patients (8 percent) were understaged in N-level. The accuracy of magnetic resonance imaging for determining depth of wall invasion was 47 percent, with 64 percent accuracy for nodal staging. CONCLUSIONS: Magnetic resonance imaging is commonly used in staging of pelvic malignancies because of its fine resolution, but chemoradiotherapy may decrease its accuracy. Thickening of the rectal wall after radiation by marked fibrosis, and peritumoral infiltration of inflammatory cells and vascular proliferation may contribute to overestimation of stage. By contrast, pathologic residual cancer beneath normal mural structure after chemoradiation therapy may result in understaging of rectal cancer.

Adult↗

PubMed2005

Cell-competition algorithm: a new segmentation algorithm for multiple objects with irregular boundaries in ultrasound images.

Segmentation of multiple objects with irregular contours and surrounding sporadic spots is a common practice in ultrasound image analysis. A new region-based approach, called cell-competition algorithm, is proposed for simultaneous segmentation of multiple objects in a sonogram. The algorithm is composed of two essential ideas. One is simultaneous cell-based deformation of regions and the other is cell competition. The cells are generated by two-pass watershed transformations. The cell-competition algorithm has been validated with 13 synthetic images of different contrast-to-noise ratios and 71 breast sonograms. Three assessments have been carried out and the results show that the boundaries derived by the cell-competition algorithm are reasonably comparable to those delineated manually. Moreover, the cell-competition algorithm is robust to the variation of regions-of-interest and a range of thresholds required for the second-pass watershed transformation. The proposed algorithm is also shown to be superior to the region-competition algorithm for both types of images.

Algorithms↗

PubMed2005

Mortality, morbidity and functional outcome after total or subtotal abdominal colectomy in the Asian population.

OBJECTIVE: This study reviews the functional outcome and satisfaction of patients after subtotal or total colectomy (STTC). METHODS: A retrospective review of patients who underwent STTC between June 1999 and September 2003 was performed. A standardized questionnaire was formulated and phone interviews were conducted with these patients. RESULTS: There were 50 patients who underwent STTC during this period. The most common indications were bleeding diverticular disease, patients with synchronous colorectal cancers or polyps and left-sided colonic obstruction. The presence of ischaemic heart disease and the development of perioperative acute coronary syndrome were found to be statistically significant predictors of 30 day mortality with P = 0.01 and 0.05, respectively. Phone interviews were successfully conducted in 33 patients. The patients interviewed were between 4 and 54 months postsurgery. Ninety-four percent reported that they were either happy or satisfied. Cleveland Clinic Incontinence Score (CCIS) revealed good or perfect continence in 94% of patients. Less than one-quarter of those interviewed had five or more bowel movements in a day while most had either two or three bowel movements a day. Patient satisfaction after STTC correlated strongly with the severity of CCIS and number of bowel movements a day (P < 0.01). Also, those with less than five bowel movements a day were more likely to report a better satisfaction (P < 0.01). CONCLUSION: Subtotal or total colectomy is associated with a good functional outcome and most patients were satisfied with their bowel function on follow-up.

Adult↗

PubMed2005

Endoscopic retrograde cholangiopancreatography management of common bile duct stones in a surgical unit.

BACKGROUND: Choledocholithiasis, if left untreated, can lead to significant morbidity and mortality. The management of such a problem has progressed tremendously but controversy still exists as to ideal management, laparoscopic exploration or endoscopic retrograde pancreatography with sphincterotomy. The purpose of this study is to evaluate the results of endoscopic retrograde cholangiopancreatography (ERCP) in a surgical unit. METHODS: We performed a retrospective review on 336 patients who underwent ERCP between 1997-2000. RESULTS: We achieved a successful cannulation rate of 98% and stone clearance rate exceeding 90%. Morbidity has been minimal and there was no mortality in our study. CONCLUSION: We conclude that ERCP is an effective and safe surgical alternative for the management of choledocholithiasis.

Adult↗

PubMed2005

A pilot study applying digital radiography for estimating ratio of supported single-root surface area.

BACKGROUND: The prognosis of a tooth with periodontitis is affected by the amount of supporting bone. A key factor in retaining a tooth is the ratio of supported root surface. Currently, root surfaces cannot be accurately measured using conventional dental radiographs, which only measure the length of bone support on proximal surfaces. METHODS: Eight extracted, single-rooted teeth were 3-dimensionally digitized using a contact technique for true surface area measurements. Root length, projection area, and pixel values were then measured on digital radiographs. The accuracy of the ratio estimation of supported surface area from linear, area, and pixel values was calculated and compared. RESULTS: The mean error from linear estimation was 7.9%; the mean error from area estimation was 1.0%; and the mean error from pixel value estimation was 1.3%. One-way analysis of variance (ANOVA) showed significant differences in all estimations while Scheffé's analysis further revealed significant differences only in the linear estimation. CONCLUSIONS: A three-dimensional digitizing device could be used as a non-destructive method of measuring root surface area. The ratio of supported single-root surface area could be estimated with high accuracy from the projected area data acquired on the digital dental radiographs. The thickness data as reflected from the pixel values in the digital images did not improve the estimation accuracy. Estimations using only length data yielded significantly less accuracy. Digital dental x-ray images provide the potential for estimating the ratio of supported root surface efficiently.

Analysis of Variance↗

PubMed2004

Effects of maternal undernutrition during late gestation on the lung surfactant system and morphometry in rats.

Intrauterine growth restriction (IUGR) is associated with reduced lung function during infancy and throughout adulthood. We investigated the effects of maternal undernutrition (50% rations of the control food intake) during the last week of gestation on the pulmonary surfactant system and lung morphometry in postnatal rats. IUGR rats exhibited a significantly lower body weight, lower lung weight, lower lung/body weight ratio, lower lung volume, and lower lung volume/body weight ratio on some postnatal days. IUGR rats had a significantly lower lung saturated phosphatidylcholine and lower plasma corticosterone levels on postnatal d 1 only, and values were comparable between control and IUGR rats in the ensuing weeks. Lung surfactant protein (SP)-A, SP-B, SP-C, and SP-D mRNA expressions were similar between control and IUGR rats. Volume fractions of the alveolar airspace were significantly lower in IUGR rats on postnatal d 7, 14, and 42. Alveolar surface areas were significantly lower in IUGR rats during the study period. The alveolar surface area/body weight ratio reached a peak on postnatal d 7, and values were significantly lower in IUGR rats on postnatal d 1, 14, 28, and 42. We conclude that maternal undernutrition during late gestation decreases lung surfactant lipid levels in the immediate postnatal period and alters the development of lung structure during the postnatal period. Alteration of lung surfactant and structure may be important in the pathogenesis of impaired pulmonary function in IUGR infants and children.

Animals↗

PubMed2004

Accuracy of supported root ratio estimation from projected length and area using digital radiographs.

BACKGROUND: The purpose of this study was to evaluate the accuracy of supported single-root surface ratio estimated from the length and projected area of the tooth, using digital dental radiographs. METHODS: Eight extracted, single-root teeth were three-dimensionally digitized using a contact technique for surface area measurement. The data were then processed using engineering application software and length, projection area, and true surface area of the root at a designated length were obtained. Based on these three measurements, the accuracy of the supported surface area ratio measurement at different lengths of the root was evaluated. RESULTS: The largest mean errors from linear and area estimation were 9.58% and -1.16%, respectively. The 95% confidence intervals were all positive, indicating that linear measurements overestimated supported ratio. T tests showed that linear estimations resulted in significant differences in all eight teeth and area estimations in five teeth. When analyzing the supported ratio of the alveolar bone receding from the cemento-enamel junction (CEJ) toward the apex of the root at each mm, linear estimation showed significant differences down to 8 mm, while area estimation showed significant differences only up to 2 mm. CONCLUSIONS: The results of this study indicate that a reliable estimate of the ratio of root surface area supported by alveolar bone cannot be determined from linear or area data. However, when the marginal bone destruction exceeds 2 mm from the CEJ, area estimation does not show a significant difference in the supported region. As demonstrated in this study, root surface ratio estimation function could be an advantage of digital dental x-ray systems in which projected root area is readily observed.

Alveolar Process↗

PubMed2004

Clinical features of influenza A and B in children and association with myositis.

Influenza virus is among the most common causes of respiratory illness, which may manifest as a range of conditions, from mild upper respiratory tract infection to bronchiolitis and pneumonia. Acute childhood myositis associated with influenza occurs mostly in influenza B infection. In this retrospective study, we analyzed the characteristics of 197 children with influenza virus treated from January 2000 to December 2001. Among them, 73 children had influenza A infection and 124 had influenza B infection. Influenza A virus outbreaks occurred in January 2000, July 2001, and December 2001, while influenza B virus outbreaks occurred from March 2000 to May 2000 and from December 2000 to February 2001. The most common clinical manifestations of influenza A and influenza B virus infection included fever, cough, and rhinorrhea. These infections also frequently manifested as laryngo-tracheobronchitis, pneumonia, and unexplained fever, which led to hospitalization. The most common clinical diagnosis was upper respiratory tract infection. The rates of benign acute childhood myositis in influenza A and influenza B were 5.5% and 33.9%, respectively. Creatine kinase levels were elevated in most myositis cases and boys were more commonly affected. Acute childhood myositis was more commonly seen in influenza B infection.

Child↗

PubMed2004

Femoral neuropathy after pelvic surgery.

Postoperative femoral neuropathy is an uncommon complication occurring after pelvic surgery. Inappropriate stretching and prolonged compression of the nerve are 2 major mechanisms of the neuropathy. Here we report 2 cases of femoral neuropathy immediately following pelvic surgery. Both cases had neither previous vascular nor peripheral nerve disease. They suffered from weakness of left hip flexion and knee extension and sensory impairment over the left lower limb after surgery. Electromyography and nerve conduction studies confirmed left femoral neuropathy. Both of the patients received physical therapy and had nearly total neurological recovery within 3 months. We report this unusual complication that followed major pelvic surgery and also review the literature and discuss the possible etiology for prevention of this injury.

Adenocarcinoma↗

PubMed2003

How aggressive should we be in patients with stage IV colorectal cancer?

PURPOSE: The prognosis for metastatic colorectal cancer is grave. Whether to perform surgical resection or palliative treatment remains controversial for this advanced disease. In this retrospective study, we collected data from patients with Stage IV colorectal cancer to identify prognostic factors for predicting selection criteria for surgical treatment in patients with metastatic disease. METHODS: A retrospective chart review was performed for patients treated from 1992 to 1999 from the Koo Foundation Sun Yat-Sen Cancer Center Tumor Registry. Seventy-four patients were identified as having Stage IV disease at the time of diagnosis. Data concerning the patients' demographics, laboratory results, operative procedure, mortality, morbidity, and survival were collected. Independent variables and survival time were analyzed by the independent t-test method. The difference was considered statistically significant at P < 0.05. RESULTS: Overall survival time for the patients with Stage IV colorectal cancer was 16.1 months. Survival in the curative resection group was significantly longer than that in the noncurative group (31.9 vs. 12.7; P < 0.016). The operative mortality and morbidity rates were 5.6 percent (4 of 71) and 21.1 percent (15 of 71), respectively. The two most common complications were leakage at the site of anastomosis and urinary tract infection. Based on these results, we conclude that patients older than 65 years, with metastases at multiple sites, intestinal obstruction, preoperative carcinoembryonic antigen level > or =500 ng/ml, lactate dehydrogenase > or =350 units/liter, hemoglobin <10 mg/dl, or hepatic parenchymal replacement by tumor >25 percent have poor prognosis for surgical intervention. CONCLUSION: Whether to perform primary tumor resection in patients with asymptomatic Stage IV colorectal cancer remains controversial; however, the more aggressively we perform radical resection and metastasectomy to selected patients, the more survival benefits the patients obtain.

Adult↗

PubMed2003

Adaptive ultrasonic speckle reduction based on the slope-facet model.

The flat-facet model has been implicitly assumed for the structure of the image surface by most conventional speckle-reduction algorithms. However, this model is rarely found in a real ultrasound (US) image. To preserve the higher order structures and to capture the spatially variant property of the speckle, a new adaptive speckle-reduction algorithm, called the symmetrical speckle-reduction filter (SSRF), was developed based on the slope-facet model. The basic idea of the SSRF was to estimate the uncorrupted signal on the largest symmetrical slope facet centered at each target pixel. The symmetry constraint ensured the correctness of the mean value. An empirical speckle model was incorporated to account for the nature of the speckle in US image. A two-stage despeckling strategy was employed to enhance the statistical reliability of each estimate by forming a union of a set of symmetrical despeckling windows. The proposed SSRF algorithm was compared with two filtered-based and one wavelet-based approaches and the experimental results showed that the proposed SSRF outperformed these three previous approaches in both the synthetic images and the clinical US images tested in this study.

Acoustics↗

PubMed2003

Methylprednisolone effects on oxygenation and histology in a rat model of acute lung injury.

We examined the effects of methylprednisolone on gas exchange, pressure-volume curve, lavage fluid inflammatory cell counts, protein content, surfactant pool size, and lung histology in a rat model of paraquat-induced lung injury. Twenty-three adult male Sprague-Dawley rats received intraperitoneal paraquat injection (35 mg/kg) and were randomly divided into three groups: (1). control group received no further treatment; (2). 1-dose methylprednisolone group received a concomitant intraperitoneal methylprednisolone injection (30 mg/kg); (3). 3-dose methylprednisolone group received a concomitant and daily intraperitoneal methylprednisolone injection (30 mg/kg) for three doses. Three days after paraquat injection, the rat was ventilated for 90 min, a static pressure-volume curve and bronchoalveolar lavage was performed, and postmortem histology was examined. Surfactant pool size of the 3-dose methylprednisolone group was significantly increased when compared with the control and 1-dose methylprednisolone groups. Methylprednisolone treatment increased oxygenation and the value was statistically significant for 3-dose methylprednisolone group at 90 min of ventilation. Inflammatory cell counts in bronchoalveolar lavage fluid and lung injury score were decreased as the methylprednisolone dose increased. We conclude that high-dose methylprednisolone treatment increased surfactant pool size and improved lung histology of paraquat-injured lungs but this augmentation could not significantly improve oxygenation throughout the ventilation period.

Animals↗

PubMed2003

Effects of baicalin on the gene expression of surfactant protein A (SP-A) in lung adenocarcinoma cell line H441.

Pulmonary surfactant, a complex lipoprotein, is secreted by alveolar type II cells. It lies at the alveolar air-fluid interface and prevents alveolar collapse by reducing surface tension. The high incidence of respiratory distress syndrome (RDS) in premature infants results principally from a deficiency of pulmonary surfactant. Surfactant protein A (SP-A) is the most abundant surfactant protein and reduces surface tension at the alveolar air-liquid interface in lung cells. In this study, RT-PCR and Western blot analyses of SP-A were performed to evaluate the biological activity of baicalin, a Chinese medicine prescribed extensively for preventing miscarriage. In in vitro experiments, lung adenocarcinoma cell line H441 was cultured with baicalin in varying concentrations and for varying lengths of time. The results show that the expression of SP-A gene was positively affected by baicalin in dose-dependent and time-course manners. The maximal expression of the SP-A gene, 1.7-fold greater than control, is induced at 150 nM of baicalin treated for 48 h.

Blotting, Western↗