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.

Skull metastasis with brain invasion from thyroid papillary microcarcinoma

Thyroid papillary microcarcinoma has a notably benign clinical course among carcinomas. The occurrence of distant metastases is exceptional, but significantly increases the risk of mortality. We report the case of a 75-year-old woman with a 1.0 cm primary thyroid papillary microcarcinoma with skull metastases and brain invasion. The clinical presentation was a large mass over the occipital area which progressively grew over the course of 1 year. No thyroid nodule or lymph nodes were palpable. The metastatic mass and primary tumor were surgically removed. The serum thyroglobulin level was 163 ng/mL 1 month after surgery. There was no further management because the patient refused follow-up. She returned to the hospital 15 months later due to a seizure. The tumor had further extended into the brain tissue. Her condition progressively deteriorated and she died 2 months later due to uncontrollable seizures.

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 χ 2 ). 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.

Ketoacidosis with hyperglycemia in heavy drinkers: a report of 12 cases

BACKGROUND

Heavy alcohol intake (> 45 g daily) might be a cause of diabetes. The short-term risks of heavy alcohol intake include ketoacidosis, glucose intolerance and pancreatitis. Alcoholic ketoacidosis (AKA) in combination with hyperglycemia mimics diabetic ketoacidosis (DKA). We described the characteristics of heavy drinkers with ketoacidosis and hyperglycemia but without a prior history of diabetes.

METHODS

Twelve habitually heavy drinkers who had not been previously diagnosed as diabetes were identified by reviewing the records of diabetic patients admitted to Chang Gung Memorial Hospital from 1989 to 1992. All of them met DKA criteria.

RESULTS

Elevated glycohemoglobulin (HbAlc) level is an indicator for the diagnosis of diabetes. Among these 12 patients, 10 had elevated levels of HbAlc and 2 had normal HbAlc levels. Of these 2 patients, 1 had an elevated level of HbAlc 6 months later; the other who was a female who after observation, had normal levels of HbAlc and glucose for the follow-up of two years.

CONCLUSION

We found that most heavy drinkers with both ketoacidosis and hyperglycemia also had diabetes as indicated by high levels of HbAlc. The only female patient had normal HbAlc and was diagnosed as AKA rather than DKA.

CYP2D6-related oxidation polymorphism in a Canadian Inuit population

The xenobiotic oxidation polymorphism associated with cytochrome P450 2D6 (CYP2D6) was investigated in 152 genetically related and unrelated healthy Inuit subjects living in the High Arctic of eastern Canada. Phenotyping was based on HPLC determination of the CYP2D6-related dextromethorphan metabolic ratio in overnight urine samples after oral administration of 30 mg dextromethorphan hydrobromide. The log metabolic ratio was bimodally distributed, with three subjects classified as poor metabolizers (PMs). In subjects unrelated in the first degree, the incidence of the PM phenotype was 3 of 90 or 3.3%. PCR-based analyses of DNA for variants of the CYP2D6 gene demonstrated that the PMs of dextromethorphan had the defective allele CYP2D6*4. The estimated frequency of the CYP2D6*4 allele was 0.067-0.083, which is lower than the frequency in Caucasians but higher than the frequency in Oriental populations. The CYP2D6*3 and the CYP2D6*6 alleles were not detected in the Inuit population. The CYP2D6*10 allele was present in only four unrelated subjects, classified as extensive metabolizers (EMs), resulting in an estimated allele frequency of 0.022, which is much lower than in Oriental populations. This study demonstrated the existence of the CYP2D6 polymorphism in Canadian Inuit, while the frequencies of allelic variants of CYP2D6 point to the uniqueness of this population. Several important therapeutic drugs that are being prescribed in Arctic communities will have altered pharmacokinetics in PMs of CYP2D6.

Posttraumatic stress symptoms, intrusive thoughts, loss, and immune function after Hurricane Andrew

OBJECTIVE

To examine the impact of and relationship between exposure to Hurricane Andrew, a severe stressor, posttraumatic stress symptoms and immune measures.

METHODS

Blood draws and questionnaires were taken from community volunteer subjects living in the damaged neighborhoods between 1 and 4 months after the Hurricane.

RESULTS

The sample exhibited high levels of posttraumatic stress symptoms by questionnaire (33% overall; 76% with at least one symptom cluster), and 44% scored in the high impact range on the Impact of Events (IES) scale. A substantial proportion of variance in posttraumatic stress symptoms could be accounted for by four hurricane experience variables (damage, loss, life threat, and injury), with perceived loss being the highest correlate. Of the five immune measures studied Natural Killer Cell Cytotoxicity (NKCC) was the only measure that was meaningfully related (negatively) to both damage and psychological variables (loss, intrusive thoughts, and posttraumatic stress disorder (PTSD). White blood cell counts (WBCs) were significantly positively related with the degree of loss and PTSD experienced. Both NKCC (lower) and WBC were significantly related to retrospective self-reported increase of somatic symptoms after the hurricane. Overall, the community sample was significantly lower in NKCC, CD4 and CD8 number, and higher in NK cell number compared to laboratory controls. Finally, evidence was found for new onset of sleep problems as a mediator of the posttraumatic symptom-NKCC relationship.

CONCLUSIONS

Several immune measures differed from controls after Hurricane Andrew. Negative (intrusive) thoughts and PTSD were related to lower NKCC. Loss was a key correlate of both posttraumatic symptoms and immune (NKCC, WBC) measures.

The enhanced tumorigenic activity of a mutant epidermal growth factor receptor common in human cancers is mediated by threshold levels of constitutive tyrosine phosphorylation and unattenuated signaling

Deregulation of signaling by the epidermal growth factor receptor (EGFR) is common in human malignancy progression. One mutant EGFR (variously named DeltaEGFR, de2-7 EGFR, or EGFRvIII), which occurs frequently in human cancers, lacks a portion of the extracellular ligand-binding domain due to genomic deletions that eliminate exons 2 to 7 and confers a dramatic enhancement of brain tumor cell tumorigenicity in vivo. In order to dissect the molecular mechanisms of this activity, we analyzed location, autophosphorylation, and attenuation of the mutant receptors. The mutant receptors were expressed on the cell surface and constitutively autophosphorylated at a significantly decreased level compared with wild-type EGFR activated by ligand treatment. Unlike wild-type EGFR, the constitutively active DeltaEGFR were not down-regulated, suggesting that the altered conformation of the mutant did not result in exposure of receptor sequence motifs required for endocytosis and lysosomal sorting. Mutational analysis showed that the enhanced tumorigenicity was dependent on intrinsic tyrosine kinase activity and was mediated through the carboxyl terminus. In contrast with wild-type receptor, mutation of any major tyrosine autophosphorylation site abolished these activities suggesting that the biological functions of DeltaEGFR are due to low constitutive activation with mitogenic effects amplified by failure to attenuate signaling by receptor down-regulation.

Macroaggregated albumin potentiates the hypoglycemic effect of microencapsulated islets in the fed state of streptozotocin-induced diabetic mice

Prolonged postprandial hyperglycaemia was noted in streptozotocin-induced diabetic mice which had been treated intraperitoneally with 2000-3000 alginate-poly-L-lysine-alginate (A-P-A) microencapsulated rat islets. We hypothesized that the persistent postprandial hyperglycaemia was due to shortage of intracapsular calcium ion. In order to study the effect of encapsulated macroaggregated albumin (MAA) on the function of microencapsulated islets, we coencapsulated MAA and islets in A-P-A microcapsules which we implanted intraperitoneally into streptozotocin-induced diabetic mice. From binding study and Scatchard analysis, we found that MAA-containing A-P-A microcapsules had a lower calcium binding affinity 5.24 +/- 1.20 mM versus 2.35 +/- 0.86 mM, n = 12, p < 0.01) and a higher calcium binding capacity (14.34 +/- 1.22 micrograms/mg versus 7.24 +/- 0.82 micrograms/mg, n = 12, p < 0.01) than empty A-P-A microcapsules. After intraperitoneal transplantation of 2000-3000 microcapsules containing islets and encapsulated MAA, the basal and postprandial blood glucose levels of the treated diabetic mice were not significantly different from that of normal mice. The improvement of persistent postprandial hyperglycaemia in these treated diabetic mice was not due to the difference of food intake in amount. In conclusion, A-P-A microcapsules containing islets and encapsulated MAA functioned better than microcapsules containing islets alone in treating streptozotocin-induced diabetic mice. The former preparation restored both fasting and postprandial hyperglycaemia and put these treated diabetic mice into a cured status of diabetes.

Prolyl aminopeptidase gene from Flavobacterium meningosepticum: cloning, purification of the expressed enzyme, and analysis of its sequence

In spite of the numerous studies regarding prolyl aminopeptidase, little is known about its mechanism and the significance of its similarity to a number of hydrolases of diverse specificity that belong to the alpha/beta hydrolase-fold family (Pseudomonas 2-hydroxymuconic semialdehyde hydrolase, atropinesterase, and 2-hydroxy-6-oxophenylhexa-2,4-dienoic acid hydrolase; human and rat epoxide hydrolases). We report the cloning and sequencing of the novel prolyl aminopeptidase gene from Flavobacterium meningosepticum (FPAP) which allowed a more comprehensive sequence comparison. FPAP was found to be a 35-kDa monomeric enzyme, releasing N-terminal proline but not hydroxyproline residues from small peptides and naphthylamide esters. Using the unweighted pair group method with arithmetic mean method, an evolutionary tree that depicts the probable relationship between the prolyl aminopeptidases and the alpha/beta hydrolase-fold enzymes was constructed. Since the alpha/beta hydrolase-fold family might also include the members of the prolyl oligopeptidase family (prolyl oligopeptidase, dipeptidyl peptidase IV, and prolyl carboxypeptidase), this proposal links all the known Pro-Y bond-cleaving proline-specific peptidases (prolyl oligopeptidase family, prolyl aminopeptidases, and prolinase) as enzymes with similar scaffolds and hydrolytic mechanisms. On the other hand, the enzymes that cleave X-Pro bonds are metalloenzymes grouped within the "pita-bread" fold family (aminopeptidase P and prolidase). Although the latter two enzymes show significant sequence homology, prolyl aminopeptidase, prolinase, and the members of the prolyl oligopeptidase family do not, and might share the alpha/beta hydrolase-fold scaffold. This rationale would explain the failure in finding a common "proline-recognizing motif" in the primary structures of these proline-specific peptidases.

Enhanced tumorigenic behavior of glioblastoma cells expressing a truncated epidermal growth factor receptor is mediated through the Ras-Shc-Grb2 pathway

A mutant epidermal growth factor receptor (DeltaEGFR) containing a deletion of 267 amino acids from the extracellular domain is common in human glioblastomas. We have previously shown that the mutant receptor fails to bind EGF, is constitutively phosphorylated, and confers upon U87MG glioblastoma cells expressing it (U87MG. DeltaEGFR), an increased ability to form tumors in mice. Here we demonstrate that the constitutively phosphorylated DeltaEGFR enhances growth of glioblastoma cells through increased activity of Ras: 1) there was an increase in the proportion of Ras present in the GTP-bound form, and 2) introduction of neutralizing anti-Ras 259 antibodies into U87MG and U87MG.DeltaEGFR cells by microinjection inhibited DNA synthesis to the same low level in both cell populations. We also show that the truncated EGF receptor constitutively associates with the adapter proteins Shc and Grb2 which are involved in the recruitment of Ras to activated receptors. Several derivatives of DeltaEGFR containing single, or multiple mutations at critical autophosphorylation sites were constructed and used to demonstrate that the major Shc binding site is Tyr-1148, and that Grb2 association occurs primarily through Tyr-1068. We conclude that the increased tumorigenic potential of glioblastoma cells expressing the truncated EGF receptor is due at least in part to Ras activation presumably involving the Shc and Grb2 adapter proteins.

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.

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.

Antipsoriatic anthrones with modulated redox properties. 3. 10-thio-substituted 1,8-dihydroxy-9(10H)-anthracenones as inhibitors of keratinocyte growth, 5-lipoxygenase, and the formation of 12(S)-HETE in mouse epidermis

The synthesis of a series of 1,8-dihydroxy-9(10H)-anthracenones bearing sulfur-linked substituents in the 10-position is described. These compounds were evaluated for their ability to inhibit the growth of the human keratinocyte cell line HaCaT and the 5- and 12-lipoxygenase enzymes in bovine polymorphonuclear leukocytes and mouse epidermal homogenate, respectively. In addition, the following redox properties of the compounds were determined: reactivity against 2,2-diphenyl-1-picrylhydrazyl, generation of hydroxyl radicals as measured by deoxyribose degradation, and inhibition of lipid peroxidation in model membranes. Compounds 4e and 4h of this series compare favorably in the cellular assays with the antipsoriatic anthralin. They have the combined inhibitory action against leukotriene B4 and 12(S)-HETE formation and are highly potent antiproliferative agents against keratinocyte growth. In contrast to anthralin, 4h, 1,8-dihydroxy-10-[(4-hydroxyphenyl)thio]-9(10H)-anthracenone, is not cytotoxic as documented by the LDH activity released from cytoplasm of keratinocytes and does not enhance lipid peroxidation in model membranes.

Cytotoxicity of unsaturated metabolites of valproic acid and protection by vitamins C and E in glutathione-depleted rat hepatocytes

Valproic acid (VPA) and the unsaturated metabolites, 2-ene VPA and (E)-2,(Z)-3'-diene VPA, demonstrated dose-dependent cytotoxicity in primary cultures of rat hepatocytes, as evaluated by lactate dehydrogenase (LDH) leakage. Cellular glutathione (GSH) was depleted by adding buthionine sulfoximine (BSO) to the culture medium. Induction of cytochrome P450 by pretreatment of rats with phenobarbital or pregnenolone-16 alpha-carbonitrile enhanced the cytotoxicity of parent VPA in BSO-treated hepatocytes. The cytotoxicity of 4-ene VPA was apparent in BSO-treated hepatocytes with detectable loss of cell viability at 1 microM of added 4-ene VPA. Depletion of cellular GSH also increased the cytotoxicities of 2-ene VPA and (E)-2,(Z)-3'-diene VPA. The cytotoxicity of 2-ene VPA was comparable to or higher than that of VPA, producing loss of viability at concentrations > or = 5 mM. Time-course evaluation of hepatocyte response to 4-ene VPA in the GSH-depleted state revealed a delayed cytotoxicity with no effect during the first 12 h of exposure followed by a pronounced toxicity between 12 and 14 h. Two major GSH conjugates of 4-ene VPA metabolites, namely 5-GS-4-hydroxy VPA lactone and 5-GS-3-ene VPA, were detected in 4-ene VPA treated hepatocytes. Consistent with this finding, a 50% decrease in cellular GSH levels was observed following 4-ene VPA treatment. Under similar conditions, neither toxicity nor the GSH conjugated metabolite were detected in cells treated with the alpha-fluorinated 4-ene VPA analogue (alpha-F-4-ene VPA). The antioxidants, vitamin C and vitamin E, demonstrated a cytoprotective effect against 4-ene VPA-induced injury in GSH-depleted hepatocytes. These results are in support of hepatocellular bioactivation of VPA via 4-ene VPA to highly reactive species, which are detoxified by GSH. The susceptibility of hepatocytes to VPA metabolite-mediated cytotoxicity depends on cellular GSH homeostasis.

The accuracy of ultrasonography and 201Tl-99mTc subtraction scan in localization of parathyroid lesions

We reviewed 27 patients who received preoperative localization using both parathyroid ultrasonography and parathyroid 201Tl-99mTc subtraction (TTS) scan from March 1986 to July 1993 in Chang Gung Memorial Hospital, Linkou. These 27 patients were diagnosed hyperparathyroidism by the pathological reports. There were 16 patients with primary hyperparathyroidism [PHPT; 9 males, 7 females; (mean age: 56.3 +/- 4.6 yrs)] and 11 patients with secondary hyperparathyroidism [SHPT; 8 males, 3 females; (mean age: 38.3 +/- 2.5 yrs)] due to end stage renal disease. The diagnostic accuracy was compared, and the results were as follow: (1) in localization of PHPT, the sensitivity and specificity of ultrasonography were 75.0% and 95.8% respectively, whereas the sensitivity and specificity of TTS were 87.5% and 100.0% respectively. The differences were not statistically significant; (2) the sensitivity and specificity of ultrasonography and TTS for patients with SHPT were 32.4% and 85.7% vs. 32.4% and 100.0%; and (3) higher sensitivity and specificity were achieved when both methods were chosen for localizing either PHPT or SHPT.

Clinical experience of medullary thyroid carcinoma in Chang Gung Memorial Hospital

Total 19 cases of medullary thyroid carcinoma (MTC) diagnosed at Chang Gung Memorial Hospital from Jan. 1979 to Dec. 1994 were studied retrospectively. All of them were pathologically proved. All cases except one were thought as sporadic MTC. The gender distribution showed a female preference with female : male (F:M) ratio of 3.8:1. The mean age at diagnosis was 44.9 +/- 13.7 years. The most common clinical presentation was thyroid mass in all (100%). The staging of MTC in our cases demonstrated: 12 (63%) stage I, 1 (5%) stage II, 3 (16%) stage III, and 3 (16%) stage IV. Thyroid ultrasonography with fine-needle aspiration cytology (FNAC) were performed in 15 patients. Eleven cases were diagnosed as malignancy, including 5 cases diagnosed as MTC preoperatively. Neck nodal metastases were noted in 7 cases and all occurred in tumors larger than 3 cm. All cases received operation according to clinical stage. Six of 7 patients who had preoperative calcitonin data showed abnormal high values. After operation, there were 8 patients with persistent hypercalcitoninemia. Of these, 5 received 131I therapy which induced undetectable calcitonin level in 2 stage I patients. Three cases received external beam radiotherapy but all failed. During a period of 0.5 to 9.4 years follow-up (mean +/- SE: 3.6 +/- 0.7 years), 3 patients died of pulmonary infection, 1 lost follow-up and 15 patients are alive and well. In conclusion, the preliminary data suggests that the medullary thyroid carcinoma in Taiwan has following characteristics: (1) gender distribution showed a female preference; (2) accuracy of preoperative FNAC was 42%; (3) most of the diagnoses of MTC were made postoperatively.

Silencing of p16/CDKN2 expression in human gliomas by methylation and chromatin condensation

The product of the p16/CDKN2 locus, p16ink4, negatively regulates the cell cycle through binding and inactivation of cyclin-dependent kinases (CDKs) 4 and 6. This locus is frequently targeted for deletion in cell lines and primary tumor tissues. In gliomas, although up to 50% do not have detectable expression of p16/CDKN2 protein or mRNA, often the gene is wild type in sequence. Here, we tested the hypothesis that transcriptional repression of p16/CDKN2 in gliomas may be mediated by aberrant methylation of the CpG island, which is in the 5' region of the locus. Partial rather than complete p16/CDKN2 methylation was detected in 24% (10 of 42) of the gliomas, regardless of tumor grade, but was not observed in normal brain (0 of 10). We tested whether this partial methylation could inhibit expression in a human tumor cell line in which suppressed p16/CDKN2 expression was associated with both methylation and tightly compacted chromatin around the p16/CDKN2 promoter. Exposure of these cells to 5-aza-2-deoxycytidine resulted in a dramatic increase in promoter accessibility and induction of p16/CDKN2 expression, indicating that chromatin structure, CpG island methylation, and p16/CDKN2 expression are intimately associated. Taken together, these data suggest that methylation occurs in only a subset of cells within gliomas and that the methylation-associated inactivation of p16/CDKN2 expression observed in many common human cancers may mechanistically result from structural changes in the chromatin containing the p16/CDKN2 locus.

No primary association between the 308 polymorphism in the tumor necrosis factor alpha promoter region and insulin-dependent diabetes mellitus

Whereas TNF-alpha has been implicated in the pathogenesis of IDDM, its possible role as a primary genetic susceptibility factor has not been well investigated. In this study, we analyzed a biallelic polymorphism in the TNF-alpha promotor region in a large collection of IDDM patients and controls ascertained from two ethnic populations (U.S. Caucasians and Chinese in Taiwan). We report that the associations with TNF-alpha are due to linkage disequilibrium between TNF-alpha and the DR3-DQB1*0201 haplotype in both ethnic populations. Our analyses of extended haplotypes for the HLA region further substantiate the conclusion that no primary association exists between IDDM and the TNF-alpha promoter polymorphism.

Identification of malnutrition-related diabetes mellitus among hospitalized patients in Taiwan

A retrospective review of 1,089 diabetes mellitus admitted to the metabolic ward of Chang Gung Memorial Hospital was performed to screen for malnutrition-related diabetes mellitus (MRDM). None of the patients fulfilled the MRDM criteria, although 20 patients with a body mass index < or = 15 kg/m2 were further analyzed. These patients presented with poor glycemic control and most had associated chronic diseases. C-peptide levels were < 0.8 ng/mL in 17 patients and undetectable in six patients. Two patients experienced diabetic ketoacidosis (DKA). Insulin treatment was required by 18 patients with a mean (+/- SD) dosage of 30 +/- 9 U/day. During follow-up of 14 of the patients for 9.8 +/- 4.3 months, HbA1c decreased significantly. Their mean body weight and body mass index increased significantly from 36.6 +/- 4.6 kg to 47.2 +/- 6.2 kg and 13.9 +/- 0.9 to 18.0 +/- 1.9 kg/m2, respectively. Careful attention should be paid to diabetic control and associated chronic illness in patients with severe undernutrition.

Surgical treatment of papillary and follicular thyroid carcinoma

There is limited clinical information about the prognostic factors in survival and distant metastasis for well differentiated thyroid cancer in Chinese patients. Pitfalls were noted when applying the results of published studies to another population. In order to realize the differences of these factors between different areas, we retrospectively analyzed the data of 569 papillary or follicular thyroid carcinoma patients who received their primary treatment at the Chang Gung Memorial Hospital during the period from January 1979 to June 1994. Actuarial survival rates were calculated by the Kaplan-Meier method. For the analysis of prognostic variables, 14 clinical parameters were coded into the computer for the univariate and multivariate analyses. Multivariate analysis was performed to assess the independent effect of these variables using the Cox model. Among these cases, there were 466 papillary thyroid carcinoma (81.9%), 103 cases of follicular thyroid carcinoma (18.1%). The subjects included 440 female patients with mean age of 38.8 +/- 14.4 years and 129 male patients with the mean age of 44.7 +/- 14.4 years (p = 0.0001). Most of the cases received total thyroidectomy treatment after the diagnosis was confirmed by a frozen section during the operation. In the follow-up period, 30 (5.3%) patients died of metastatic thyroid cancer. The one year Greenwood survival probability after the disease diagnosed in papillary and follicular thyroid carcinomas was 0.986 and 0.909 respectively. Using a log-rank univariate analysis, survival was significantly associated with the histological type of primary tumors, age, clinical staging, post-operative 131I pattern, tumor size, postoperative serum thyroglobulin (Tg) level and post-operative X-ray findings. Tumor size larger than 2.5 centimeters could influence both the survival and distant metastases of these well differentiated thyroid cancer patients. In the Cox multivariate regression analysis, the combination factors that gave the best prognostic values were the association of distant metastasis (0.005), age (p = 0.027), and one month postoperative serum Tg level (p = 0.042). Well differentiated thyroid cancer is not an unusual disease in Taiwan. In this limited period of follow-up study, distant metastasis at the time of surgery, the patients' age and one month post-operative serum Tg level may serve as the prognostic factors for the well differentiated thyroid cancer patients.

Induction of CYP3A and associated terfenadine N-dealkylation in rat hepatocytes cocultured with 3T3 cells

Long-term culture of hepatocytes has been challenged by the loss of differentiated functions. In particular, there is a rapid decline in cytochrome P450 (CYP). In this study, we cocultured rat hepatocytes with 3T3 fibroblasts for 10 days, and examined hepatocyte viability, morphology, and expression of CYP3A. Terfenadine was incubated with the cultures, and its biotransformation was quantitatively analyzed by HPLC. Terfenadine is metabolized by two major pathways: C-hydroxylation to an alcohol metabolite which is further oxidized to a carboxylic acid, and N-dealkylation to azacyclonol. In rat liver, only the N-dealkylation pathway appears to be mediated by CYP3A since anti-rat CYP3A antibody inhibited azacyclonol but not alcohol metabolite formation in incubations of terfenadine with liver microsomes. Freshly isolated rat hepatocytes were seeded on top of confluent 3T3 cells. Cultures were maintained in Williams' E medium supplemented with 10% fetal bovine serum and either 0.1 mumol/L or 5 mumol/L dexamethasone. In pure hepatocyte cultures, viability, as determined by lactate dehydrogenase (LDH) activity, decreased steadily to less than 30% of initial levels by day 10. In cocultures, LDH activity remained high and was 70% of initial levels on day 10. The half-life of terfenadine disappearance was optimally maintained in cocultures treated with 5 mumol/L dexamethasone, and was associated with the increased formation of azacyclonol. On day 5, nearly 50% of added 5 mumol/L terfenadine was converted to azacyclonol within 6 h, whereas the conversion was only 4% on day 1. Western and RNA-slot blot analyses confirmed that treatment with 5 mumol/L dexamethasone induced CYP3A mRNA expression and CYP3A protein expression. This coculture system could offer a useful approach in the study of drugs and xenobiotics metabolized by CYP3A.

HLA-encoded susceptibility to insulin-dependent diabetes mellitus is determined by DR and DQ genes as well as their linkage disequilibria in a Chinese population

HLA-DRB1 and -DQB1 genes were analyzed in 98 Chinese IDDM patients and 205 control subjects from Taiwan. The DRB1*0301-DQB1*0201 haplotype conferred strong susceptibility (RR = 7.7, pc < 10(-5)). DRB1*0405 also conferred susceptibility (RR = 3.1, Pc < 0.0005) whereas DRB1*0403 (RR = 0.7) and DRB1*0406 (RR = 0.2) conferred protection. Indeed, the relative risk for the DRB1*0405-DQB1*0302 haplotype (RR = 33.7, Pc < 0.002) was 48 and 168 times higher than those conferred by the DRB1*0403-DQB1*0302 and DRB1*0406-DQB1*0302 haplotypes, respectively, suggesting that the protection conferred by DRB1*0403 and 0406 is dominant over DQB1*0302. The strong linkage disequilibrium observed between DQB1*0302 and DRB1*0403(0406) can thus explain the surprising finding that the frequency of DQB1*0302 was not significantly increased in the Chinese IDDM patients (RR = 0.9). Because the DRB1*0405-DQB1*0302 haplotype (RR = 33.7) conferred higher susceptibility than the DRB1*0405-DQB1*0401 (RR = 2.5) or DRB1*0405-DQB1*0301 (RR = 2.1) haplotypes, DQB1*0302 is indeed a susceptibility factor, while both DQB1*0301 and DQB1*0401 may confer protection against IDDM. The increased frequency of the protective DQB1*0401 allele in patients compared to controls is due to linkage disequilibrium between DRB1*0405 and DQB1*0401. Interestingly, the previously demonstrated protective effect of DQB1*0602 was not very strong in the Chinese (RR = 0.4). Our results suggested that HLA-encoded susceptibility to IDDM is determined by the combined effects of all DR and DQ molecules present in an individual. Therefore, the genotypic combinations of DR and DQ genes as well as their linkage disequilibria can influence IDDM susceptibility. At least four DR and DQ molecules conferring high susceptibility (DRB1*0301, DRB1*0405, and DQ alpha/beta 0301/0201 and 0301/0302) occur at high frequency in the Chinese population. However, linkage disequilibria between highly susceptible DR and protective DQ or vice versa (e.g., DRB1*0405-DQB1*0301[0401] and DRB1*0403[0406]-DQB1*0302) are probably responsible for the lower incidence of IDDM in the Chinese.