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Biomedical subjects

T W Chen

Publications and source records attributed to T W Chen.

At least 19 recordsLinked to original sources
PubMed2006

Intrapericardial isolation of the inferior vena cava through a transdiaphragmatic pericardial window for tumor resection without sternotomy or thoracotomy.

AIMS: The prognosis for patients with advanced tumors invading the inferior vena cava (IVC) is dismal and surgical treatments for these tumors are challenging. A surgical approach that avoids sternotomy and thoracotomy for tumors invading the IVC even to the level of the hepatocaval junction would be extremely helpful. METHODS: The intrapericardial IVC was isolated via a transdiaphragmatic pericardial window using a transabdominal approach. Hepatectomy was then applied via an anterior approach until the IVC was seen. Total hepatic vascular exclusion was achieved by clamping the portal triad, intrapericardial IVC and infrahepatic IVC. We removed the primary tumor, the liver portion involved and the tumor thrombi, with segmental resection of the IVC. Vascular continuity was reestablished using a 20-mm-diameter polytetrafluoroethylene graft. RESULTS: Four patients with tumors invading the IVC were treated with this method. All underwent gross en-bloc tumor resections and all survived. CONCLUSION: This method for the resection of IVC tumors could avoid emboli dislodging from the tumor thrombi, prevent the complications of sternotomy, cardiopulmonary bypass and shorten operative times.

Adrenal Cortex Neoplasms↗
PubMed2006

Comparison of clinical staging systems in predicting survival of hepatocellular carcinoma patients receiving major or minor hepatectomy.

AIM: To compare the utility of seven commonly used staging systems in the prediction of survival among patients with hepatocellular carcinoma (HCC) undergoing major or minor hepatectomy. METHODS: All patients were classified by the Okuda, the TNM, the CLIP, the BCLC, the CUPI, the JIS and the MELD classifications to estimate the probabilities of survival. Survival curves were calculated using the Kaplan-Meier method and were examined using log-rank testing. The overall predictive power for patient survival with each staging system was evaluated using linear trend chi(2) tests and from the area under the receiver operating characteristic (ROC) curve. RESULTS: In our patient cohort, the log-rank test and the linear trend chi(2) test of the CLIP and JIS systems gave better results than did the other staging systems. The discriminatory ability of the CLIP and JIS staging for death, evaluated by ROC curve areas, was also better. In the subgroups of major hepatectomy patients with a non-cirrhotic liver or minor hepatectomy patients with a cirrhotic liver, the CLIP and JIS systems showed similar better performances in these three tests. The discriminatory ability of the CLIP system was the best in major hepatectomy patients with a non-cirrhotic liver while JIS score discriminated best in minor hepatectomy patients with a cirrhotic liver. CONCLUSION: Among the seven staging systems, the CLIP and JIS systems perform better than do the others. While the CLIP system should be considered to stage major hepatectomy patients, the JIS system could be chosen to stage minor hepatectomy patients.

Carcinoma, Hepatocellular↗
PubMed2005

An alternative technique for totally implantable central venous access devices. A retrospective study of 1311 cases.

AIM: The aim of the present study was to report our experience of totally implantable central venous access devices (TICVAD) implantation using two techniques and attempt to define the better technique. MATERIALS AND METHODS: From January 1998 to September 2003, 1131 patients were reviewed and divided into two groups with implantation by cephalic vein cut-down (group A) done by general surgeons and subclavian vein puncture with the Seldinger technique (group B) done by vascular surgeons. The operative time, early and late complications of these two groups were compared. Data were analysed by Student's t-test. RESULTS: The average of operative time was 43 min in group A (35-70 min) and 40 min in group B (35-60 min) (P>0.05). No post-operative pneumothorax, hemothorax and fragmentation occurred in group A; the incidence of peri-operative complication was higher in group B. The overall and early complications of group A were significantly lower than that of group B (P<0.0001). CONCLUSION: This retrospective study showed that the cephalic vein cut-down approach for TICVAD placement avoided the risks of pneumothorax, hemothorax and catheter fragmentation.

Blood Vessel Prosthesis Implantation↗
PubMed2005

Prediction of the risk of hepatic failure in patients with portal vein invasion hepatoma after hepatic resection.

AIM: Hepatic failure can develop after curative hepatectomy in patients with a hepatocellular carcinoma (HCC) invading the portal vein, because of cirrhosis and excessive tissue loss. This study aimed to identify the risk factors for hepatic failure in such patients. METHOD: Forty patients with an HCC invading the portal vein underwent curative hepatectomy from January 1995 to June 2003. Eight patients developed hepatic failure and died within 3 months. Possible risk factors for this were analysed using univariate and multivariate regression. These included the liver function index, surgical blood loss, tumour pattern, portal hypertension, estimated residual liver volume measured by computed tomography (ERLV(CT)) and estimated residual liver volume using the indocyanine green (ICG) retention rate at 15 min (ERLV(ICG15)). RESULTS: The ERLV(CT) smaller than the ERLV(ICG15) and presence of portal hypertension were independent risk factors for post-hepatectomy hepatic failure. CONCLUSION: Having portal vein invasion HCC with portal hypertension or an ERLV(CT) less than an ERLV(ICG15) are significant predictors of post-hepatectomy hepatic failure. These factors are important considerations for patients with portal vein invasion HCC who could undergo curative hepatic resection.

Carcinoma, Hepatocellular↗
PubMed2003

The effect of surgical stress on insulin sensitivity, glucose effectiveness and acute insulin response to glucose load.

Hyperglycemia after stress is a very common clinical phenomenon. It is generally hypothesized that the underlying cause is a neuroendocrine-mediated deterioration in glucose metabolism. However, the detailed roles of insulin sensitivity, glucose effectiveness and acute insulin response to glucose load in response to stress have not been well established. Hernioplasty was used as a minor stress model for studying stress-induced hyperglycemia. Eleven healthy young men were enrolled voluntarily in this study. Their mean age was 22.0 +/- 0.9 yr and BMI 23.3 +/- 0.6 kg/m2. Frequently sampled i.v. glucose tolerance tests were performed one day before and one day after the surgery. Insulin sensitivity (SI), glucose effectiveness (EG) and area under acute insulin response (AIR) were calculated from "minimal model" algorithms. We also measured fasting concentrations of human GH, ACTH and F on the days of the test. Compared to the pre-operation data, levels of ACTH and F did not change significantly after the surgery. Only GH levels were marginally significant. On the other hand, the SI (0.75 +/- 0.1, 0.52 +/- 0.9 x 10(-5) min(-1)/pmol, p = 0.04), EG (0.023 +/- 0.03, 0.016 +/- 0.003 min(-1), p = 0.01) and AIR (6738.5 +/- 1111.6, 5130.0 +/- 1047.2 pmol, p = 0.005) were all significantly decreased after surgery. The percentages of decrease were 16.3 +/- 15.5, 32.1 +/- 10.3 and 17.8 +/- 10.3%, respectively. Finally, only the changes of EG positively correlate with the changes of ACTH before and after surgery. No significant changes were noted among other stress hormones and the changes of SI, EG and AIR. In conclusion, hernioplasty results in reduced SI, EG and AIR. Among them, although not statistically significant, the EG showed the most distinct decrease after the surgery, which has not been found in previous literature.

Adolescent↗
PubMed2003

Interpretation of skull radiographs for facial fractures by medical staff working in UK emergency departments: a pilot study.

OBJECTIVES: This was a pilot study to determine the ability of hospital doctors (1) to assess the technical quality of occipitomental (OM) radiographs and (2) to identify facial fractures. METHOD: Twenty-two doctors from four UK Accident and Emergency (A&E) departments participated in a two part study: Part A was a postal questionnaire containing questions on demographic data, educational background, selection criteria, assessing radiographs and radiation protection; and Part B was a clinical viewing session to interpret 20 randomized OM radiographs divided into four groups; technically good and poor without fractures, and technically good and poor with fractures. RESULTS: Study participants ranged from junior house officers to senior consultants. There was considerable variation in educational background and radiographic interpretation instruction at undergraduate and postgraduate level. OM radiographs constituted 10% of all skull radiographs examined per week, yet only 40% of the doctors felt confident when assessing technical quality. The majority of participants had only a limited knowledge of radiation protection legislation. During the viewing session, only 50% of the participants correctly identified those radiographs with fractures and those with technique errors. There was no significant difference between house officers and other grades of staff. A higher level of seniority did not equate with greater interpretative ability. Subjective confidence in assessing film quality did not correlate with the actual film viewing. CONCLUSION: Only half of the A&E doctors taking part in the study were able to correctly assess film quality and identify facial fractures on OM radiographs. If the pilot sample is representative, then the findings are of considerable concern.

Clinical Competence↗
PubMed2001

Thiamine deficiency and unexplained encephalopathy in hemodialysis and peritoneal dialysis patients.

Patients with end-stage renal disease undergoing regular dialysis are prone to encephalopathy, but the cause is often unclear. Dialysis patients are at risk for thiamine deficiency, which may mimic many uremic complications, including encephalopathy. To determine whether unexplained encephalopathy in regular dialysis patients is associated with thiamine deficiency, we conducted a prospective study that enrolled 30 consecutive dialysis patients with altered mental status admitted to a referred hospital during a 1-year period. A complete history, physical and neurological examinations, laboratory investigations, and computed tomographic scans or magnetic resonance imaging of the brain were obtained for each subject. In 10 of the 30 patients, diagnoses remained obscure after the initial workup. Manifestations included confusion, chorea, acute visual loss, rapidly progressive dementia, myoclonus, convulsions, and coma. Intravenous thiamine was administered to these 10 patients. All 10 patients had thiamine deficiency confirmed by a marked response to thiamine supplementation and/or a low serum thiamine concentration (35.3 +/- 6.0 nmol/L; normal, >50 nmol/L). Nine patients recovered, but one patient failed to respond because of delayed treatment. We conclude that in regular dialysis patients, unexplained encephalopathy can be mainly attributed to thiamine deficiency. This condition is fatal if unrecognized and can be successfully treated with prompt thiamine replacement.

Adult↗
PubMed2000

The effects of weight reduction on the rehabilitation of patients with knee osteoarthritis and obesity.

OBJECTIVE: To evaluate the effect of weight reduction on the rehabilitation of patients with knee osteoarthritis and obesity. METHODS: A total of 126 patients with bilateral knee osteoarthritis and obesity were classified into 3 groups by their stages of osteoarthritis. Each group was divided into subgroups a, b, and c. The subjects in subgroup a received weight reduction treatment, those in subgroup b received weight reduction and electrotherapy modalities, and those in subgroup c received electrotherapy modalities to relieve pain. RESULTS: Pain reduction, weight reduction, ambulation speed, and changes of Lequesne's index were greater in patients in subgroups a and b than in subgroup c after treatment. Although the last pain scores in subgroup b were less than those in subgroup a, as measured by a visual analog scale (VAS), there was no significant difference between their functional status. Significant pain relief (VAS < 2) and an acceptable functional status (Lequesne's index < 7) were indicated when weight reduction was more than 15% and 12%, respectively, of the initial body weight of the individual. CONCLUSION: Weight reduction was found to be a practical adjuvant treatment in the rehabilitation of patients with knee osteoarthritis.

Acupuncture Therapy↗
PubMed2000

Mycotic aneurysm of the abdominal aorta in a patient undergoing hemodialysis: an unusual complication of Staphylococcus aureus bacteremia.

When Staphylococcus aureus is repeatedly positive in blood cultures even under effective antibiotics therapy (vancomycin, teicoplanin, or rifampin), computed tomography scan and sonography should be performed early to exclude mycotic aneurysm of the deeply seated arteries, especially in patients with abdominal aortic calcification. Before 1990, the most common causative organism of suprarenal aortic mycotic aneurysm was Salmonella; since 1990, it has been gram-positive cocci (i.e., Streptococcus and Staphylococcus) rather than gram-negative bacilli (i.e., Salmonella), possibly because of the more invasive procedures performed in clinical settings, but this hypothesis needs further investigation.

Aged↗
PubMed2000

Significance of nitrogen removal mass in uremic patients on different modalities of dialysis therapy.

BACKGROUND AND PURPOSE: While most nephrologists use Kt/V values for dialysis prescriptions, some researchers are beginning to view the role of solute removal mass as an indicator of adequate dialysis. This study, using nitrogen as a surrogate for solute removal, probed whether solute removal mass can be used as the target of adequate dialysis. Mathematical formulas for easy bedside calculation of nitrogen removal mass were used to avoid the problems associated with direct measurement. METHODS: The weekly removal mass of urea nitrogen (M) and the urea generation rate (G) of 32 conventional hemodialysis (HD) and 21 continuous ambulatory peritoneal dialysis (CAPD) patients were calculated. All the patients were anuric, clinically stable, and under adequate dialysis pursuant to either the criterion of the urea index, Kt/V, or clinical requirements. RESULTS: The difference in MHD (MHD = 41.9 +/- 9.5 g/week, MCAPD = 38.8 +/- 11.9 g/week) and G (GHD = 3.90 +/- 1.02 mg/min, GCAPD = 3.85 +/- 1.21 mg/min) between the two groups was statistically insignificant (p = 0.119 and p = 0.868, respectively). When protein nitrogen leaking through the peritoneal membrane was considered and added to MCAPD, nitrogen removal in CAPD patients (M'CAPD = 42.3 +/- 13.0 g/week) approached that in HD patients (p = 0.886). There was no correlation between dialysis dosage and urea removal mass in either the CAPD or HD groups. CONCLUSIONS: Urea nitrogen removal mass is similar to the protein catabolic rate (PCR) in stable patients. It is meaningful in dialysis evaluation only when it is used simultaneously with blood urea nitrogen measurement. However, because M changes at the inception of dialysis, it more significant than PCR in the evaluation of unstable patients.

Adult↗
PubMed2000

The effect of electroacupuncture on shoulder subluxation for stroke patients.

In this study, we evaluated the effect of electroacupuncture on shoulder subluxation for stroke patients. Twenty hemiplegic patients with shoulder subluxation were randomly and equally divided into two groups. The subjects in the control group received conventional therapy, and the subjects in the study group were treated with electroacupuncture and conventional therapy for four weeks. The visual analog scale (VAS) for shoulder pain, motor function status, anthropometry, and X-ray assessment were used to evaluate the status of shoulder subluxation before and after treatment. The results indicated that the pain scores decreased in the study groups significantly more than those in the control group. The degrees of shoulder reduction, including the measurement of anthropometry and X-ray assessment in the study group, were more than those of the control group. However, the motor function status showed no significant difference between two groups. It is concluded that electroacupuncture can be an effective adjuvant management in the treatment of shoulder subluxation for stroke patients.

Adolescent↗
PubMed1999

Erythropoietin hyporesponsiveness: from iron deficiency to iron overload.

Iron deficiency is the most frequently encountered cause of suboptimal response to recombinant human erythropoietin (rHuEPO). Carefully assessing iron status is of paramount importance in chronic renal failure patients prior to or during rHuEPO therapy. Because there is great need for iron in the EPO-stimulated erythroid progenitors, it is essential that serum ferritin and transferrin saturation levels should be maintained over 300 microg/liter and 30%, respectively. Investigators have shown that oral iron is unlikely to keep pace with the iron demand for an optimal rHuEPO response in uremics. Therefore, patients with iron deficiency will always require intravenous iron therapy. The early and prompt iron supplementation can lead to reductions in rHuEPO dose and hence cost. After the iron deficiency has been corrected or excluded, we must remember all of the possible causes of hyporesponsiveness in every rHuEPO-treated patient. As dose requirements vary, it is not clear which dose of rHuEPO causes this hyporesponsiveness. However, if the patient with iron repletion does not respond well after the induction period, the major causes blunting the response to rHuEPO should be investigated. Most factors are reversible and remediable, except resistant anemia associated with hemoglobinopathy or bone marrow fibrosis, which requires a further increase in the rHuEPO dose. By means of early detection and correction of the possible causes, the goal of increasing therapeutic efficacy can be achieved. Iron overload may lead to an enhanced risk for infection, cardiovascular complication, and cancer. Over-treatment with iron should be avoided in dialysis patients, despite the fact that the safe upper limit of serum ferritin to avoid iron overload is not clearly defined. On the other hand, functional iron deficiency may develop even when serum ferritin levels are increased. Controversy remains as to whether intravenous iron therapy can overcome this form of hyporesponsiveness in iron-overloaded patients. Moreover, a treatment option of iron supplementation is not warranted in these patients, as the potential hazards of iron overload will be worsened. We demonstrated that the mean hematocrit significantly increased from 25.1+/-0.9% to 31+/-1.2% after eight weeks of intravenous ascorbate therapy (300 mg three times a week) in 12 hemodialysis patients with serum ferritin levels of more than 500 microg/liter. The enhanced erythropoiesis paralleled with a rise in transferrin saturation (27.8+/-2.5% vs. 44.8+/-9.5%, P < 0.05) and reductions in erythrocyte zinc protoporphyrin (130+/-32 vs. 72+/-19 micromol/mol heme, P < 0.05) and monthly rHuEPO dose (24.2+/-4.5 vs. 16.8+/-3.4 x 10(3) units, P < 0.05) at the end of study. It is speculated that ascorbate supplementation not only facilitates the iron release from storage sites and its delivery to hematopoietic tissues, but also increases iron utilization in erythroid cells. Our study provides a more complete understanding of the pathogenesis of iron overload-related anemia and the development of an adjuvant therapy, intravenous ascorbic acid, to the existing treatments.

Aluminum↗
PubMed1999

Is serum transferrin receptor a sensitive marker of iron repletion in patients with iron-deficiency anemia and hemodialysis patients?

BACKGROUND: Serum transferrin receptor (sTfR) concentration has been recognized as a reliable laboratory indicator of iron deficiency in recent years. But its response to iron supplementation has not been investigated. METHODS: We evaluated the sTfR concentrations in 15 patients diagnosed with iron-deficiency anemia, in 30 patients receiving maintenance hemodialysis (HD) with iron repletion and in 31 healthy controls. The serial changes of sTfR concentration and their correlation with serum ferritin in patients with iron deficiency under iron repletion were also examined in three patients. RESULTS: In patients with iron-deficiency anemia, the sTfR concentration was 5.6 +/- 2.4 mg/ml, significantly higher than that in the control group (1.8 +/- 0.4 mg/ml) and patients receiving maintenance HD with iron repletion (1.7 +/- 0.5 mg/ml). The three patients with iron-deficiency anemia who received eight to 16 weeks of iron supplementation showed steady and significant decreases in sTfR concentration and significant increases in serum ferritin and transferrin saturation. However, the decreases in sTfR concentration did not occur immediately, as did the increases in serum ferritin and transferrin saturation, following iron repletion. There was a four-week delayed response in the decrease of sTfR concentrations as measured against serum ferritin and transferrin saturation. CONCLUSIONS: sTfR concentration may not be as effective as an early index of iron repletion compared with serum ferritin and transferrin saturation.

Adult↗
PubMed1999

Prosthetic reconstruction in the cleft lip and palate patient with an extracoronal resilient attachment retained removable partial overdenture: case report.

There are still some difficulties in prosthetic reconstruction of cleft lip and palate patients with conventional prostheses or implant retained prostheses. The most common difficulties are insufficient alveolar bone quality and quantity, inadequate soft tissue, and abutment teeth. The patient we report on was a 23-year-old man with a clinical diagnosis of right incomplete cleft lip and palate combined with midface dysplasia. The maxillary six anterior teeth were reconstructed. The maxillary right central incisor and canine were used as abutments for an extracoronal resilient attachment (ERA) retained removable partial overdenture. The STERN ERA SYSTEM is a hinged resilient attachment with an ideal stress breaking characteristic, a good retentive function, and easy chairside replacement. The 2-year follow-up examination revealed an adequate esthetic appearance with good retention and stability of the prosthesis. A removable partial overdenture using the teeth adjacent to the cleft area as abutments with an adequate attachment design is an alternative method for prosthetic reconstruction of cleft lip and palate deformity.

Adult↗