Biomedical subjects

T C Chao

Publications and source records attributed to T C Chao.

At least 73 records · Page 4Linked to original sources

PubMed1997

Pancreaticojejunal anastomotic leak after pancreaticoduodenectomy--multivariate analysis of perioperative risk factors.

The records of 131 consecutive patients with periampullary carcinoma who underwent pancreaticoduodenectomy within a 12-year period were reviewed to determine the perioperative risk factors of pancreaticojejunal (PJ) anastomotic leak. Twenty-one PJ leaks were identified, for a frequency of 16% (21 of 131); 19% (4 of 21) of these patients eventually died of PJ leak-related complications. A total of 23 items of perioperative data, presumed as risk factors predisposing to PJ leak, were examined. By univariate analysis, advanced age, prolonged duration of untreated jaundice, deep jaundice, decreased creatinine clearance, increased intraoperative blood loss, and shock during operation were statistically significant. However, by multivariate analysis, only duration of jaundice, creatinine clearance, and intraoperative blood loss turned out to be independent risk factors. Noteworthily, jaundiced patients with impaired creatinine clearance not only had a higher incidence of PJ leak, but were also more liable to experience sepsis and intraabdominal bleeding, which uniformly elicited a grave clinical course. Routine preoperative biliary drainage failed to enhance the security of PJ. Completion pancreatectomy continued to carry a poor prognosis, and should be avoided when possible and replaced by early, aggressive radiologic intervention.

Adult↗

PubMed1997

Experimental pulmonary sarcoma metastases in athymic nude mice.

BACKGROUND: Pulmonary metastases remain a challenging therapeutic problem in the treatment of patients with soft tissue sarcomas. A pulmonary sarcoma metastases animal model might facilitate studying the biology of metastases, diagnosis, and treatment modalities of this disease. Intravenous injection of human tumor cells into nude mice has been reported using human melanoma and colorectal carcinoma to produce pulmonary metastases. Human fibrosarcoma cells were intravenously administered to athymic nude mice to simulate clinical pulmonary metastases. METHODS: HT-1080 human sarcoma cells derived from a poorly differentiated fibrosarcoma were used to prepare inoculant at a concentration of 5 x 10(6) cells per ml. Male athymic nude mice were injected subcutaneously with 1 x 10(6) cells in the right hind flank and sacrificed when the tumors were 1-2 cm in diameter. Age- and weight-matched athymic nude mice were intravenously injected through tail veins with 10(4), 10(5), and 10(6) cells. The mice were sacrificed at 7, 14, and 21 days after intravenous injection of the tumor cells. Tissues were histologically examined for pulmonary metastases. RESULTS: Neither gross nor microscopic spontaneous metastases were found in any of the animals that received subcutaneous xenografts, and no pulmonary metastases were identified in mice intravenously injected with < 10(5). All mice inoculated with 10(6) cells developed tumor colonies in the lungs, which were microscopically evident as early as day 7. No metastases were found in the liver, spleen, heart, or other tissues. In a second experiment, HT-1080 cells were injected at 10(6); all animals developed lung metastases and died of lung tumor involvement, with an average survival of 35 days. CONCLUSIONS: These experiments identify a sarcoma animal pulmonary metastases model that is readily available, relatively inexpensive, easily utilized, and reproducible.

Animals↗

PubMed1997

Binding and internalization of anti-sarcoma IgG and IgM antibodies.

A variety of monoclonal antibodies directed against tumor cell surface antigens have been employed for tumor detection and delivery of toxins and radioisotopes to tumors in situ. The sequence of events following antibody binding to tumor cells may be critical to the success or failure of tumor imaging or therapy. Using indirect immunofluorescence, we have examined the binding and internalization of two different monoclonal antibodies (19-24 and MFH 4.10) by HT-1080, a cultured human sarcoma cell line. MAb 19-24 (IgG1) and MAb MFH 4.10 (IgM) are directed against surface antigens on cells from human malignant fibrous histiocytoma (MFH). For both of these antibodies, the initial binding on the surface of HT-1080 cells at 4 degrees C was uniform. After binding secondary fluorescent antibody, monoclonal antibodies underwent rapid internalization at 37 degrees C. Surface-bound antigen-antibody complexes were completely cleared from the cell surface in 30-60 min. In the absence of secondary fluorescent antibody, MAb 19-24 remained bound to the cell surface at 37 degrees C for up to 20 hr without being released or internalized. However, under these same conditions MAb MFH 4.10 was internalized completely within 30 min by HT-1080 cells and did not subsequently return to the cell surface. Such differences in the mechanisms of binding and uptake for these two antibodies may have significant implications for their future clinical or therapeutic uses.

Animals↗

PubMed1997

Factors that predict metastasis of papillary and follicular thyroid cancers in Taiwan.

The purpose of this study is to explore the relationship of postoperative thyroglobulin level and other clinical factors with tumor metastasis. Analysis of 281 pathologic lesions verified patients with papillary and follicular thyroid cancer who received their primary treatment at Chang Gung Memorial Hospital. Clinical information-including postoperative thyroglobulin levels, age, sex, primary tumor size, clinical staging, surgical methods, surgical findings, chest x-ray findings, and 131I uptake-were stored in the computer. Actual survival rate and univariate and multivariate analyses of these factors with the relationship of distant metastases were undertaken. Twenty-three patients in this study died of distant metastases from the thyroid cancer. Of these patients, 30.4% were older than 60 years. In contrast only 8.5% of patients in the survival group were older than 60 years (p < 0.05 in chi2). All of the papillary thyroid cancer patients with distant metastases displayed thyroglobulin levels higher than 25 ng/ml, but only 24% (41 of 173 cases) of those without distant metastases had thyroglobulin levels higher than 25 ng/ml. In 12 follicular thyroid cancer patients with distant metastases, 11 patients' serum thyroglobulin levels were higher than 25 ng/ml. In contrast, only 7 of 33 patients with follicular thyroid cancer without distant metastases displayed similar thyroglobulin levels. Univariate analysis revealed that age, postoperative thyroglobulin levels, chest x-ray findings, pathologic type, and tumor size are associated with distant metastases. One-month postoperative serum thyroglobulin level could be used as a prognostic factor for papillary and follicular thyroid cancer patients with distant metastases.

Adenocarcinoma, Follicular↗

PubMed1997

Prognostic study of gastric cancer without serosal invasion: reevaluation of the definition of early gastric cancer.

BACKGROUND: Early gastric cancer, a term defined by Japanese researchers in the 1960s, is equivalent to pT1 tumor stage regardless of nodal status. Recently, there were suggestions to exclude node-positive pT1 gastric cancer from this entity and to consider node-negative pT2 gastric cancer as early gastric cancer. STUDY DESIGN: A survival analysis was conducted of 294 patients who underwent resection for gastric cancers confined within the gastric wall (pT1, n = 164; pT2, n = 130) between 1986 and 1992. RESULTS: The cumulative 5-year survival rate was 93.5% for pT1 patients and 67.9% for pT2 patients, with an overall survival of 82.5%. There was a significant difference in the 5-year survival rate between node-positive and node-negative pT1 patients (72.8% versus 95.6%; p = 0.0095). The 5-year survival rate of node-negative pT2 patients (80.4%) was significantly worse than that of node-negative pT1 patients (p = 0.011) but was not significantly better than that of node-positive pT1 patients (p = 0.4). If excellent prognosis is a prerequisite for the definition of early gastric cancer, then node-positive pT1 cancer and node-negative pT2 cancer should not be considered early gastric cancer. CONCLUSIONS: In the 1990s, now that new imaging techniques such as endoscopic ultrasonography has been introduced, the preoperative staging of gastric cancer can be made more accurately than in the 1960s, when the term "early gastric cancer" was defined. Because the prognosis of early gastric cancers, if subcategorized by nodal status, is not homogeneously excellent, a reevaluation of the definition of early gastric cancer may be necessary.

Adolescent↗

PubMed1997

Beware of charm needles!

This report describes the case of a man accused of murder who had the prosecution case dismissed after he complained that he had been coerced (following assault with a needle) into providing a statement. Subsequent events determined that a more complete examination following his complaint may not have resulted in the case being (wrongfully) dismissed.

Journal Article↗

PubMed1997

Role of hepatic resection in surgery for bilateral intrahepatic stones.

BACKGROUND: Hepatic resection is the treatment of choice for unilateral intrahepatic stones. The availability of the flexible choledochoscope has greatly changed the management of intrahepatic stones. Little has been reported regarding hepatic resection for bilateral intrahepatic stones. METHODS: Fifty-nine (15.1 per cent) of 392 patients with bilateral intrahepatic stones underwent hepatic resection. The indications and results were reported. Surgical outcome and long-term follow-up were analysed, and results were compared with those in patients not undergoing hepatectomy. RESULTS: Fifty-nine patients underwent hepatic resection because of destruction of the left liver by repeated infection (n = 40), multiple cholangitic liver abscesses (n = 18) or associated intrahepatic cholangiocarcinoma (n = 1). The hospital mortality rate was 1.7 per cent. The majority of complications were wound infection (9 per cent), haematobilia (5 per cent) and biliary fistula (3 per cent). The incidence of residual stones after surgery was 60 per cent. One year after postoperative choledochoscopic stone extraction, the rate of complete stone clearance was 84 per cent. In patients who did not have hepatectomy the respective rates were 90.1 and 52.9 per cent. The recurrence rate for stones in the hepatectomy and no-hepatectomy groups was 12 and 33.0 per cent respectively. CONCLUSIONS: Compared with patients not undergoing hepatectomy, those having hepatic resection had similar operative risks, fewer residual stones and a low incidence of recurrent stones (P < 0.05).

Adult↗

PubMed1996

Primary carcinoma of the gallbladder in Taiwan.

To define more precisely the prognostic index for patients with primary carcinoma of the gallbladder in Taiwan, we retrospectively reviewed the data of 74 patients with gallbladder carcinoma treated over a period of 15 years, from 1979 to 1993. Of these patients, 75% had Nevin stage V gallbladder cancer. The most common presenting complaint was abdominal pain, followed by jaundice, fever, and nausea and vomiting. Accurate preoperative diagnosis was made in 29.7% of the patients. Ultrasonography and computed tomography had a diagnostic accuracy of 34.0% and 40.9%, respectively. The most common histologic type was adenocarcinoma. Liver was the organ most commonly invaded (51.9%) by direct extension and/or metastases, followed by regional lymph nodes (38.5%). The overall 5-year survival rate was 4.1%. Age, sex, white cell count, hemoglobulin, SGOT, SGPT, total bilirubin, alkaline phosphatase, and cholelithiasis were not significant prognostic factors. Patients with cancers confined in the gallbladder wall (stages I, II, III) had a better (P < 0.05) cumulative survival rate than did those with regional lymph nodes and distant metastases. Cholecystectomy or extended surgery had a better survival rate than did palliative surgery, but there was no significant difference between cholecystectomy and extended surgery. High index of suspicion of the disease and earlier surgical treatment may improve patient survival.

Adult↗

PubMed1996

Establishment of xenografts and cell lines from well-differentiated human thyroid carcinoma.

BACKGROUND: Our aim was to establish Chinese human thyroid cancer cell lines and to provide the material for thyroid cancer research. METHODS: We collected thyroid cancer tissues from 93 patients with thyroid cancer for developing the primary culture. Thyroid cancer tissues were verified by frozen sections during the operations, then subjected to primary cell culture. During the first several passages, fibroblasts were removed by selective attachment. RESULTS: From the 93 cancer tissues used, two follicular cancer tissues from the metastatic area (CGTH W-1, CGTH W-2) and one papillary thyroid cancer tissue (CGTH W-3) could be passed over 50 times. Cellular transformation with loss of contact inhibition occurred during passages 5-8. Electron microscopic studies of the CGTH W-1 cell line showed the presence of an abundance of mitochondria and Golgi complex. Presence of microvilli with interdigitations between neighboring cells were found in CGTH W-2 and CGTH W-3 cell lines. Severe combined immunodeficient (SCID) mice were used to determine whether these cells were tumorigenic. Two months after transplantation of 1 x 10(7) CGTH W-1, 2, and 3 cells into SCID mice, subcutaneous tumors approximately 2-2.5 cm in size were clearly visible. After affinity cross-linking an IGF-I with insulin-like growth factor binding proteins complex corresponding to a molecular size of 41 kDa was observed in culture media collected from CGTH W-1, SW 579, and RO82 W-1 cells. CONCLUSIONS: Three thyroid cancer cell lines were established, which may provide material for future thyroid cancer research.

Animals↗

PubMed1996

Clinical presentations and treatment for 74 occult thyroid carcinoma. Comparison with nonoccult thyroid carcinoma in Taiwan.

There is limited clinical information of Chinese patients with occult well-differentiated thyroid cancer (OTC). The purposes of this study were to elucidate the clinical presentations and results of treatment in the patients with OTC in Taiwan. The data of 568 patients with pathologically verified papillary and follicular thyroid carcinomas who received primary treatment in Chang Gung Memorial Hospital were retrospectively reviewed. Seventy-four of 568 patients with well-differentiated thyroid carcinoma were OTC; those included 71 papillary thyroid carcinomas and three follicular carcinomas. Among the 74 OTC patients, five cases (6.8%) presented with distant metastases, but 41 cases (10.1%) were found with distant metastases in 416 nonoccult thyroid cancer (NOTC) (p = 0.509). In the five OTC with distant metastases, there were three papillary carcinomas and two follicular carcinomas. Only one case (1.4%) died of distant metastasis of the occult papillary thyroid carcinoma versus 20 cases out of the total 568 (4.1%) well-differentiated thyroid carcinomas. After statistical analysis, there were no differences between the survival rates of OTC and NOTC patients. In the present study, 1 month postoperative serum thyroglobulin level could be used as prognostic factor in both OTC and NOTC patients. Only 54.17% of OTC patients were diagnosed as thyroid cancer by thyroid ultrasonography with the fine needle aspiration cytology. In conclusion, most OTC had relatively benign clinical courses, but distant metastases may result in mortality still observed. Therefore, OTC should be treated as NOTC, since relatively high rate of distant metastases were found in the patients with OTC.

Adenocarcinoma, Follicular↗

PubMed1996

Steroid sex hormones and macrophage function: regulation of chemiluminescence and phagocytosis.

PROBLEM: Female sex hormones modulate a variety of humoral and cell-mediated immunologic functions. In this study, the effects of estrogen, progesterone, and testosterone on the chemiluminescence (CL) response and phagocytic ability of male rat peritoneal macrophages (M luminal diameter) were examined. METHOD: In M luminal diameter pretreated with 10(-2) ng/ml of 17 beta-estradiol (E2) for 20 hours, the CL generated in response to phorbol myristate acetate (PMA), 1,2-dioctanoyl-rac-glycerol (C8:0), or opsonized zymosan (OZ) was significantly increased by 135%, 140%, and 136% of control values, respectively. In addition, M luminal diameter treated with 10(-5) ng/ml or 10 ng/ml of E2 exhibited a significantly greater PMA- or OZ-stimulated CL response than did untreated controls. RESULTS: At 10(-2) ng/ml, progesterone enhanced and testosterone reduced the CL response, but these changes were not statistically significant. In time course studies, the PMA-stimulated CL response of M luminal diameter treated with 10(-2) ng/ml of E2 or progesterone for 5 h was significantly less than that of the untreated group. In the presence of endotoxin (12 pg/ml), the CL response in M luminal diameter treated with E2 or testosterone was significantly depressed as compared to untreated controls. Phagocytosis of opsonized sheep erythrocytes also was significantly enhanced (140% to 190% of control) when M luminal diameter were pretreated with 10(-12) M to 10(-8) M of either E2 or progesterone. CONCLUSIONS: These findings suggest that, at physiological concentrations, E2 is capable of modulating both CL generation and phagocytic uptake by M luminal diameter in a manner not shared by other steroid hormones.

Animals↗

PubMed1996

Forensic applications of DNA profiling.

Deoxyribonucleic acid (DNA) profiling is a powerful forensic tool to identify and individualise biological evidence recovered at crime scenes. Its discriminating power and evidential value are exemplified by many actual forensic cases. Development of new DNA typing techniques, such as the amplification of fluorescently tagged short tandem repeats, would further enhance this capability in forensic investigation.

DNA↗

PubMed1996

Female sex hormones and the immune system.

Generally, females have a more active immune response and a concomitantly higher incidence of autoimmune diseases as compared to males. Growing evidence has shown that female sex hormones play a major role in this heightened immune response. However, despite extensive studies, the mechanisms of female sex hormones are not precisely understood. Earlier evidence suggest that female sex hormones acted via the thymus gland. In recent years it has become apparent that female sex hormones have distinct effects on the function of T cells, B cells, or mononuclear phagocytes. The presence of sex hormone receptors on the immune cells indicates the effects of female sex hormones on these cells are mediated by these receptors. The effects of female sex hormones on the immune system and the possible mechanisms are discussed in this review. Female sex hormone modulation of immune responses provides a basis for understanding gender-related differences in certain autoimmune and neoplastic disorders.

Animals↗

PubMed1996

Ammonia gassing deaths--a report on two cases.

The gross postmortem features of two victims (a 17-year-old and a 33-year-old male, both of Chinese descent) who died shortly after an ammonia-gassing exposure, are presented. The findings of extensive thermal burns on the body surfaces and on the lips, conjunctivitis and opaque cornea on both eyes, oedematous and congested lungs with large areas of haemorrhages, etc, were consistent with injuries inflicted by a corrosive gas such as ammonia. The postmortem toxicological findings of elevated blood ammonia levels supported the postmortem findings. The pulmonary and femoral blood ammonia levels (0.26 mg/mL and 0.65 mg/mL) of decedent one were at least 371 times and 928 times respectively higher than normal. Similarly, the pulmonary and femoral blood ammonia levels (0.51 mg/mL and 0.43 mg/mL) of decedent two were at least 728 times and 614 times respectively higher than normal.

Accidents, Occupational↗

PubMed1995

Somatostatin and macrophage function: modulation of hydrogen peroxide, nitric oxide and tumor necrosis factor release.

Recent studies have shown that somatostatin modulates lymphocyte function, but the effects of somatostatin on macrophage function are not clearly defined. In the present study, peritoneal macrophages (Mluminal diameter) obtained from male rats were treated in vitro with somatostatin or octreotide and their effects on the release of hydrogen peroxide (H2O2), nitrite, and tumor necrosis factor (TNF) determined. Macrophages treated with somatostatin (10(-9) M to 10(-7) M) or octreotide (10(-8) M and 10(-7) M) released significantly greater amounts of PMA-stimulated H2O2 than did the untreated controls. In addition, 10(-9) M of somatostatin significantly enhanced PMA-stimulated H2O2 release by LPS-treated Mluminal diameter. Octreotide had no effect on H2O2 release by LPS-treated Mluminal diameter. At concentrations of 10(-14) M, 10(-13) M, or greater than 10(-8) M, somatostatin or octreotide suppressed nitrite release by Mluminal diameter. Somatostatin or octreotide did not affect nitrite release by LPS-treated Mluminal diameter. On the other hand, Mluminal diameter treated with 10(-11) M of somatostatin or octreotide released greater amounts of TNF than did the untreated controls. In contrast, TNF release by Mluminal diameter treated with 10(-9) M to 10(-5) M of somatostatin or 10(-7) M to 10(-5) M of octreotide was less than that of the controls. Anti-TNF antibody (1:1000) caused a reduction in the release of H2O2 and nitrite. These findings demonstrate that somatostatin and octreotide modulate the release of H2O2, nitric oxide, and TNF by Mluminal diameter depending on the concentration of hormones used.

Animals↗

PubMed1995

Steroid sex hormones regulate the release of tumor necrosis factor by macrophages.

Generally, females have been found to have a heightened immune response and a concomitantly higher incidence of autoimmune diseases compared to males. We have used male rat peritoneal macrophages (M phi) to study the effect of female sex hormones on tumor necrosis factor (TNF) release. The amount of TNF released by macrophages (M phi) exposed to 10(-2) and 10(-3) ng/ml of 17 beta-estradiol (E2) (35.1 +/- 7.3 and 23.2 +/- 2.5 units/ml, respectively) was significantly (P < 0.05; n = 9) greater than that released by untreated M phi. Progesterone (P) also significantly (P < 0.05; n = 8) stimulated a maximal TNF release (24.4 +/- 2.8 units/ml TNF) at 10(-2) ng/ml. On the other hand, the amount of TNF released by M phi exposed to E2 or P at concentrations greater than 10(-1) or less than 10(-4) ng/ml was significantly (P < 0.05) reduced compared to untreated controls. In contrast, testosterone did not significantly affect TNF release at any concentration. Within the physiological range of E2 and P concentrations, TNF release from M phi is finely regulated and dramatically affected by relatively small changes in hormone concentrations.

Animals↗

PubMed1995

Primary carcinoma of the gallbladder associated with anomalous pancreaticobiliary ductal junction.

Anomalous pancreaticobiliary ductal junction (APBDJ) is a rare anomaly but is a risk factor for primary carcinoma of the gallbladder. To define the relationship between APBDJ and gallbladder carcinoma, we retrospectively reviewed data of 57 patients with gallbladder carcinoma. Of these patients, 25 had undergone endoscopic retrograde cholangiopancreaticography (ERCP) and four (16%) exhibited APBDJ. The age of those patients with APBDJ was 58.0 +/- 8.6 years and that of the patients without APBDJ was 59.2 +/- 3.1 years. Two (50.0%) of the APBDJ patients had gallstones and 47.6% of the patients without APBDJ had gallstones. The mean length of the common channel was 30 mm (range 22-38). The mode of ductal junction was three pancreatic-biliary types and one biliary-pancreatic type. One patient had an associated choledochal cyst. All the four patients with APBDJ had advanced gallbladder cancers. Consideration of gallbladder carcinoma in the patients with APBDJ may improve early detection and their survival rate.

Adenocarcinoma↗

PubMed1995

Blood aflatoxin levels in patients with hepatocellular carcinoma in Singapore.

Aflatoxin (AF), a highly potent hepatocarcinogen, is strongly implicated in the pathogenesis of human hepatocellular carcinoma (HCC). In this study, our aim was to determine if this carcinogen is associated with cases of HCC in Singapore. Blood levels of the naturally-occurring AFs--B1, B2, G1 and G2--were assayed in 56 cases of HCC. AF was detected in only 2/56 (3.6%) cases of HCC, one each of AF-B1 and AF-G1. In contrast, in a similar survey done in Singapore on normal subjects, AF was positive in 64/423 (15.1%) cases. The low frequency of AF detection in our patients suggests that HCC in Singapore is not associated with significant chronic exposure to AF.

Adult↗