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C K Chang

Publications and source records attributed to C K Chang.

At least 37 records · Page 2Linked to original sources
PubMed2003

Hyperinsulinaemia and hyperglycaemia: possible risk factors of colorectal cancer among diabetic patients.

Hyperinsulinaemia and hyperglycaemia are two possible risk factors for colorectal cancer, which constitutes the third leading cause of cancer death in Western countries. Molecular evidence as well as animal models provide support for these associations: Insulin has been shown to be an important growth factor for colonic carcinoma cells, and both insulin and insulin-like growth factor-1 receptors have been detected in colon cancer tissue. The insulin-signal transduction pathway is involved in the regulation of gene expression and apoptosis. The role of hyperglycaemia in carcinogenesis could include pathways via luminal factors (related to fecal bile acid concentrations, stool bulk, and prolonged transit time) or circulatory factors (via glucose as the only energy source for neoplastic cells). This review summarizes the epidemiologic literature with respect to hyperinsulinaemia and hyperglycaemia as risk factors for colorectal cancer, and aims to integrate the biological and epidemiological evidence. Epidemiologic findings to date indicate a slightly increased risk of colorectal cancer for diabetic patients; however, there are some inconsistencies. Possible explanations for these inconsistencies include inadequate information about patients' diabetic disease and treatment states. We suggest that future studies should take medical history, staging and treatment for hyperinsulinaemia and hyperglycaemia into account to further our understanding of the role of hyperglycaemia and hyperinsulinaemia in colorectal carcinogenesis.

Colonic Neoplasms↗
PubMed2003

High isotope counts and sentinel node positivity in patients with melanoma.

BACKGROUND: Radioisotope mapping is an essential technical component of sentinel lymph node (SLN) biopsy, and most authors define success by an arbitrary threshold SLN-background ratio. HYPOTHESIS: Few studies have examined the degree to which the relative level of SLN counts correlates with the presence of metastasis. Having removed the SLN with the highest counts, there are no data suggesting how far the surgeon should persist in removing additional SLNs that contain much lower levels of isotope. METHODS: We performed 134 SLN biopsy procedures in 132 patients with melanoma. Successful isotope localization was defined using an SLN/"hottest" SLN ratio; we defined an SLN as any node containing counts at least 10% of that of the hottest SLN. RESULTS: Of 83 patients with more than 1 SLN site identified, 21 (25%) had SLNs that contained metastasis. In 17 (81%) of these cases, the SLN with the highest countcontained tumor, but in 4 (19%) it was benign. Among these 4 patients, the counts of the hottest benign SLNs exceeded those of SLNs positive for metastasis on histological examination by a ratio of at least 10:1, and the counts of the positive SLNs were less than 4:1 of those of the background counts or the presence of blue dye failed to identify the positive SLN. No optimum ratio of SLN/SLN or SLN/background counts identified the positive SLN in all cases. CONCLUSIONS: Although the SLN with the highest counts contained metastasis in 81% of patients with malignant melanoma and multiple SLNs, neither a relatively high isotope count nor the presence of blue dye consistently predicted SLN positivity. For maximum accuracy, SLN biopsy requires the removal of all nodes containing isotope regardless of the relative magnitude of counts and the concurrent use of blue dye to salvage those procedures in which isotope mapping fails.

Adult↗
PubMed2003

Melanoma in the elderly patient.

BACKGROUND: The incidence of cutaneous melanoma is rising steadily, and the rate of increase is among the highest for any form of cancer. Although the reliability of age as a prognostic factor is debatable, several studies suggest that age has an important prognostic use. HYPOTHESIS: Age alone does not predict a poor prognosis in the older patient with melanoma. SETTING: University teaching hospital. METHODS: A retrospective review was undertaken to identify patients aged 65 years or older with intermediate-thickness melanoma (1-4 mm). Two hundred thirteen such patients were identified. Data are given as mean +/- SD. RESULTS: The mean age was 72.2+/-6.1 years. The mean follow-up was 49 months. By univariate analysis, the mean disease-free survival (DFS) and overall survival (OS) for lymph node-positive patients was 36.0+/-9.6 and 56.0+/-10.6 months, respectively. The mean DFS for node-negative patients was 155.0+/-9.8 months, and the mean OS was 166.0+/-9.2 months (P<.001 for both). The mean DFS and OS for women were 151.0+/-11.2 and 163.0+/-10.9 months, respectively. In contrast, men had 116.0+/-9.5 months' DFS and 127.0+/-9.0 months' OS (P=.01 for both). By multivariate analysis, lymph node status was the most predictive variable for DFS and OS (P<.001 for both). Sex tended to affect OS (P=.02) but did not achieve prognostic significance on DFS (P=.09). Other factors such as location, ulceration, histological type, and mitoses per square millimeter failed to show any prognostic significance. Stratification into 3 age groups (65-70, 71-80, and >80 years) had no significant effect on DFS (P=.95) or OS (P=.92). CONCLUSIONS: Lymph node status is the most important prognostic factor in older patients with intermediate-thickness melanoma. Identification of high-risk factors may help stratify these patients for recommendation of more aggressive treatment or adjuvant therapies. Among these patients, age alone was not a significant prognostic factor in the clinical management of melanoma.

Age Factors↗
PubMed2003

Significance of dual-basin drainage in patients with truncal melanoma undergoing sentinel lymph node biopsy.

BACKGROUND: The number of nodal basins and the number of lymph nodes containing regional metastases are important prognostic factors in patients with truncal malignant melanoma. Because the lymphatic drainage pattern of truncal melanoma often includes more than 1 basin, we designed a study to evaluate whether: (1) patients with dual-basin drainage were at an increased risk of lymph node metastases identified by sentinel lymph node (SLN) biopsy; and (2) the histologic status of an individual basin reliably predicted the status of the other draining basin in patients with dual-basin drainage. METHODS: The records of 269 consecutive patients with melanoma, who were treated primarily with intraoperative lymphatic mapping and SLN biopsy between 1997 and 2002, were reviewed. Of these patients, 122 had primary truncal melanomas. All patients underwent preoperative lymphoscintigraphy, which established the number and location of draining nodal basins. The chi-square and Fisher's exact tests of relevant clinicopathologic factors determined which factors were predictive of the presence of a pathologically positive SLN. RESULTS: At least one SLN was identified in all patients. Dual-basin drainage was present in 39 (32%) patients, and a pathologically positive SLN was found in 12 (31%) of these patients. By chi-square and Fisher's exact tests, dual-basin drainage was not a significant independent risk factor for the presence of at least 1 pathologically positive SLN (P =.846). Tumor thickness (P <.001), Clark level (P =.003), and tumor ulceration (P =.003) were significant independent risk factors for the presence of at least 1 pathologically positive SLN. SLN pathology in one basin did not predict the histology of the other basin in 7 (18%) of 39 patients with dual-basin drainage. CONCLUSIONS: Dual-basin drainage is not independently associated with an increased risk of nodal metastases in patients with truncal melanoma. Because the histologic status of an individual basin did not reliably predict the status of the other draining basins in patients with dual-basin drainage, it is important to adequately identify and completely assess all nodal basins at risk, as defined by lymphoscintigraphy, in patients with truncal melanoma.

Adult↗
PubMed2003

Dunnett's many-to-one test and least square means.

Dunnett's many-to-one test is used frequently today, especially in dose-finding studies. Using Dunnett's test, the Type I error level for the comparison between the raw mean of the control and the raw means of the study drug groups can be exactly calculated for the normal data. However, this computability depends on the independence of the raw means. Unfortunately, this independence does not exist for the model-based likelihood estimates (least square means) in the cases of ANCOVA and two-way ANOVA models without interaction for unbalanced data. This paper investigates this dependence between the least square means and derives some new procedures to calculate the joint distribution of the statistic for Dunnett's test.

Analysis of Variance↗
PubMed2003

Role of sentinel lymph node biopsy in patients with thin (<1 mm) primary melanoma.

BACKGROUND: Thin melanomas have become increasingly prevalent, and lesions < or =1 mm in thickness are frequently diagnosed. They are considered highly curable when treated solely with wide local excision, with reported 5-year disease-free survivals of 95% to 98%. However, thin Clark level III and IV melanomas may have increased potentials for metastasizing and late recurrences because of dermal lymphatics located at the interface of the papillary and reticular dermis. We have addressed this controversial area by reviewing the outcomes of patients with invasive thin melanomas. METHODS: We performed 266 sentinel lymph node biopsy procedures, using both radioisotope and blue dye, over a 5-year period. Sixty-five of the 266 invasive melanomas were thin and were treated by wide local excision and sentinel lymph node biopsy. RESULTS: Two (3%) of the 65 thin melanomas were found to have a positive sentinel lymph node. In melanomas thinner than.75 mm, no positive sentinel lymph node was found. Therefore, only 3% of patients may benefit from tumor upstaging by sentinel lymph node biopsy. CONCLUSIONS: The occurrence of regional lymph node metastases in thin melanomas is rather low. Our data suggest that sentinel lymph node biopsy may not justified in patients with melanoma <.75 mm thick.

Adult↗
PubMed2003

Interdisciplinary approach to abdominal Burkitt's lymphoma.

Burkitt's lymphoma is a high-grade, rapidly growing B-cell neoplasm. It is recognized by its aggressive course, brief median survival, and low rates of long-term survival. The authors discuss the case of a patient who acutely presented with intraabdominal complications from a new onset of Burkitt's lymphoma. The clinical and pathological features, staging, treatment options, and survival data are reviewed. In addition, the role of surgical intervention is carefully analyzed.

Abdominal Neoplasms↗
PubMed2003

Metastatic infiltrating syringomatous adenoma of the breast.

Infiltrating syringomatous adenoma of the breast is classified as a benign, locally invasive neoplasm. To our knowledge, there have been no reported cases of metastasizing syringomatous adenomas. We used sentinel lymph node mapping to identify metastatic cells, leading to a diagnosis of infiltrating syringomatous adenoma of the breast.

Adenoma, Sweat Gland↗
PubMed2003

Hepatic radiofrequency ablation of metastatic ovarian granulosa cell tumors.

Intrahepatic recurrences of a granulosa cell tumor of the ovary after primary resection has traditionally been considered a relative contraindication to surgical management. Improvements in ablative technologies such as radiofrequency ablation (RFA) offer the surgeon additional alternatives in the management of selected intrahepatic tumors. We present a case report of an intrahepatic recurrence of a metastatic ovarian granulosa cell tumor 6 months after primary resection. The patient received RFA of the intrahepatic lesions and the patient remains free of detectable disease 14 months later. A review of the literature is presented. This is the first known report of the use of RFA for intrahepatic recurrence of a metastatic ovarian granulosa cell tumor. In selected cases of metastatic ovarian granulosa cell tumors to the liver RFA may increase the percentage of patients considered surgically treatable.

Catheter Ablation↗
PubMed2003

Thick melanoma in the elderly.

The objective of this analysis is to ascertain the natural history of elderly patients greater than 65 years of age with thick melanoma (T4) who were treated with surgery only. Although there are multiple data on elderly patients, there is not a systematic review of survival in elderly patients over 65 years, and with our analysis we tried to enlighten this field in view especially of the growing population of the elderly in the United States. We retrospectively evaluated 112 patients with thick (> or = 4 mm) melanoma aged 65 or greater. Mean age was 73 years. Mean follow-up was 36 months. The overall survival (OS) and disease-free survival (DFS) were 69 and 52 months, respectively. Univariate analysis predicted worse OS and DFS when patients have positive lymph nodes, high mitotic rate, and increasing thickness. By multivariate analysis, lymph node status was most predictive of OS and DFS. Lymph node status is the most important prognostic factor in elderly patients with thick melanoma. Our analysis has shown that elderly patients that received no adjuvant treatment did significantly worse than the historical controls. Patients with nodal metastases are candidates for adjuvant therapy. Those without nodal disease constitute a favorable patient group and thus have much better prognosis and may not need adjuvant therapy. However, they must be closely monitored or enrolled in randomized trials. Thus, treatment for melanoma patients older than 65 should be as aggressive as in younger patients, and these patients should not be denied adjuvant treatment based on their age only.

Age Factors↗
PubMed2002

Radiofrequency ablation of the porcine liver with complete hepatic vascular occlusion.

BACKGROUND: We studied the effects of radiofrequency ablation, relative to hepatic blood flow, on the volume and shape of the resulting tissue necrosis. The extent of necrosis is directly proportional to the size of the electrode and inversely related to blood flow, which dissipates the heat generated. METHODS: Two areas of necrosis were created in each of eight porcine livers, which were assigned to four groups according to blood flow occlusion: no occlusion, occlusion of the hepatic artery and portal vein, occlusion of the hepatic veins, and complete hepatic vascular occlusion. After 25 minutes of liver reperfusion, the animals were euthanized, and the livers were examined. RESULTS: Complete vascular occlusion resulted in the greatest area of necrosis (28.6 +/- 3.4 cm(3)), followed by occlusion of the hepatic artery and portal vein (19.2 +/- 5.9 cm(3)), occlusion of hepatic veins (14.4 +/- 2.6 cm(3)), and no occlusion (4.9 +/- 1.5 cm(3)). The volume of the necrotic areas created during complete vascular occlusion were significantly greater than those created with no occlusion, as well as those created with only the hepatic artery and portal vein occluded (P <.05). CONCLUSIONS: Complete vascular occlusion, combined with radiofrequency ablation, increases the volume of necrosis and creates a more spherical ablative area.

Animals↗
PubMed2002

Blunt injury to the external iliac artery: a case report.

Blunt vascular trauma is rare as compared with penetrating vascular trauma. The incidence of iliac artery injury has been reported as low as 0.4 per cent of total arterial trauma. Iliac artery injury in blunt trauma is rare because of its anatomic location and protection by the pelvis. This article presents a case of external iliac artery injury secondary to blunt trauma. A deceleration-type mechanism is suggested that results in the production of an intimal flap and later vessel thrombosis. We discuss the clinical details of presentation and angiographic diagnosis as well as treatment options.

Abdominal Injuries↗
PubMed2001

DL-Tetrahydropalmatine may act through inhibition of amygdaloid release of dopamine to inhibit an epileptic attack in rats.

DL-Tetrahydropalmatine (THP), an active component isolated from corydalis (a Chinese herbal medicine), possesses analgesic effects. Systemic administration of picrotoxin (3-4 mg/kg) produced increases of locomotion (including horizontal motion, vertical motion, and total distance traveled), elevations of turnings (including both clockwise and anticlockwise), and inhibition of postural freezing in freely moving rats, and increases of amygdaloidal release of dopamine in anesthetizes rats. All the afore-mentioned activity measures induced by picrotoxin were suppressed following THP pretreatment. The results indicate that THP may act through inhibition of amygdaloid dopamine release to inhibit an epileptic attack.

Amygdala↗
PubMed2001

Mechanical and histological evaluations of hydroxyapatite-coated and noncoated Ti6Al4V implants in tibia bone.

This paper evaluates the behavior of hydroxyapatite (HAP) coated and noncoated Ti6Al4V implants in dog tibia after 3 and 5 months implantation. HPA-coated implants were obtained by plasma spraying. XRD, SEM, and EPMA were employed to estimate the coating characteristics and their behavior in vivo. Investigation of material characteristics showed that the as-received coatings consisted mainly of amorphism and HAP phase. Other phases such as TCP and CaO were identified due to thermal changes of HAP particles in plasma flame. SEM micrographs showed a typical microstructure of plasma-sprayed coating. The as-received coating was formed by well-melted pancake-like splats that lead to a dense coating with a rough surface. Lamellar structure, micropores, and microcracks, observed inside the coating, are characteristic of plasma spraying. Push-out tests revealed that HAP coating had a significant promotion of interfacial shear strength. The shear strength between bone and HAP-coated implants was much higher than that between bone and noncoated implants due to the different bone-implant interfaces formed after implantation. SEM observation revealed a direct attachment between HAP coating and newly formed bone. However, noncoated implants were separated from newly formed bone by fibrous tissues. Ti ions were found to be released into the surrounding environment after long time immersion in body fluid, and thus caused low shear strength. Prolongation of implantation time had different effects on shear strength. It improved the shear strength between HAP-coated implant and newly formed bone. However, it had little effect on that between noncoated implant and surrounding tissues.

Alloys↗
PubMed2001

Therapeutic effect of dimethyl sulfoxide on ICAM-1 gene expression and activation of NF-kappaB and AP-1 in septic rats.

BACKGROUND: Dimethyl sulfoxide (DMSO) is a potent antioxidant which protects against endotoxemia and septic shock in animal models. We investigated the therapeutic effect of DMSO on intercellular adhesion molecule 1 (ICAM-1) gene expression and activation of nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1) in a rat model of peritonitis sepsis. This postchallenge model simulates the clinical treatment of ruptured viscus peritonitis. MATERIALS AND METHODS: Peritonitis was produced by subjecting rats to laparotomy, followed by a 1-cm cecal incision (CI) to produce fecal soilage of the peritoneum. Rats were subjected to laparotomy only for the sham-operated group. For the protection study, DMSO (6 ml/kg) was injected ip at 30, 60, or 90 min post-CI surgery. The levels of ICAM-1 mRNA expression and activation of NF-kappaB and AP-1 in livers were determined at 3 and 6 h post-CI. RESULTS: At 3 h post-CI surgery (early sepsis), DMSO treatment at 30 and 60 min post-CI surgery significantly inhibited sepsis-induced ICAM-1 mRNA expression and activation of NF-kappaB and AP-1. DMSO has no effect on ICAM-1 gene expression and activation of NF-kappaB and AP-1 when administered at 90 min post-CI surgery. At 6 h post-CI surgery (late sepsis), DMSO administered at 30, 60, or 90 min post-CI surgery significantly inhibited ICAM-1 mRNA expression and NF-kappaB activation but not AP-1 activation. CONCLUSIONS: Therapeutic treatment of DMSO inhibited sepsis-induced activation of NF-kappaB and AP-1, resulting in the suppression of ICAM-1 gene expression in the livers of peritonitis septic rats. This finding suggests that reactive oxidants are involved in the signal transduction pathways for activation of NF-kappaB and AP-1. Thus, antioxidants which inhibit NF-kappaB and AP-1 activation may be beneficial in treating sepsis and septic shock.

Animals↗
PubMed2001

Cholesteryl ester transfer and cholesterol esterification in type 1 diabetes: relationships with plasma glucose.

The activities of two crucial enzymes of reverse cholesterol transport, cholesterol ester transfer protein (CETP) and lecithin:cholesterol acyltransferase (LCAT), and their relationships with lipid profile and fasting plasma glucose were examined in 35 type 1 diabetic children. The CETP and LCAT activities were significantly lower (p<0.05) in the 4 subjects with normal fasting plasma glucose levels (<6.39 mmol/l) than in the 28 with high plasma glucose levels (CEPT activity, 10.63+/-3.81 vs. 32.18+/-13.94 nmol/ml h; LCAT activity, 25.52+/-4.53 vs. 39.52+/-12.52 nmol/ml h; both p<0.05). The subjects with high plasma glucose levels also had higher total and LDL-cholesterol than those with normal glucose levels. CETP activity was positively correlated with fasting plasma glucose, CETP concentration, LCAT activity, total cholesterol, free cholesterol, LDL-C, and LDL-cholesteryl ester, while negatively correlated with cholesteryl ester to free cholesterol ratio, LDL triglyceride to protein ratio, and LDL triglyceride to cholesteryl ester ratio. LCAT activity was found to positively correlate with CETP activity, total cholesterol, free cholesterol, LDL-C, CETP concentration, and LDL-cholesteryl ester, while it negatively correlated with cholesteryl ester to free cholesterol ratio. The results observed in type 1 diabetic subjects suggest that (1) accelerated LCAT and CETP activities may result in the accumulation of LDL-cholesteryl ester; and (2) fasting plasma glucose may be a major determinant of CETP activity.

Blood Glucose↗
PubMed2001

Changes in endogenous monoamines in aged rats.

1. It has been documented that ageing may alter endogenous neurotransmitters. However, these results are controversial. Thus, in the present study, cerebral cortex and plasma from male Wistar rats aged 8 weeks and 6, 12 or 24 months were used to investigate the changes in monoamines using electrochemical detection. 2. A marked decrease in L-dihydroxyphenylalanine (L-DOPA) was observed in aged rats. Like the decrease in dopamine (DA), levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindolacetic acid (5-HIAA), the major metabolite of 5-HT, in aged rats were decreased in the cerebral cortex and plasma. Plasma levels of noradrenaline and levels of adrenaline in the cerebral cortex were also decreased in aged rats. Moreover, levels of 3,4-dihydroxyphenylacetic acid (DOPAC), a metabolite of DA, in the cerebral cortex and plasma were reduced by ageing. The level of homovanillic acid (HVA) in all samples was markedly increased with ageing. 3. The ratio of DOPAC/DA and 5-HIAA/5-HT, being closely linked with the activity of monoamine oxidase, was increased in the cerebral cortex and plasma with ageing. The ratio of HVA/DOPAC, an index of the activity of catechol-O-methyltransferase, was also higher in the cerebral cortex and plasma of aged rats. 4. These data suggest that ageing may alter endogenous monoamines in both the brain and peripheral tissues.

3,4-Dihydroxyphenylacetic Acid↗