A cross-sectional analysis of executive function in Down syndrome from 2 to 35 years.

BACKGROUND: Previous research has indicated a unique profile of executive function (EF) in children and adolescents with Down syndrome (DS). However, there is a paucity of research on EF in adults with DS. This study aimed to gain a broader understanding of strengths and weaknesses in EF in DS from 2 to 35 years. METHOD: Parents of 112 individuals with DS between 2 and 35 years participated in this study. Parents either completed the Behaviour Rating Inventory of Executive Function - for individuals 6+ years - or the Behaviour Rating Inventory of Executive Function Preschool Version - for children 2-5 years. RESULTS: Results suggest not only overall difficulties but also patterns of strength and weakness within EF for individuals with DS. For the 2 to 5-year-old group, emotional control and shift were relative strengths, planning/organisation and inhibit were intermediate skills, and working memory was a relative weakness. For the 6 to 18-year-old group, emotional control and organisation of materials were relative strengths, inhibit and initiate were intermediate skills, and working memory, monitor, planning/organisation, and shift were relative weaknesses. Most abilities were consistent from 2 to 18 years, except shift, which decreased in preadolescence before beginning to recover in adolescence. Across the full age range (2-35 years), composite scores indicated quadratic trends in inhibit, working memory, and planning/organisation, and a cubic trend in shift, with EF abilities generally declining in middle childhood before recovering in adulthood. CONCLUSIONS: This study extends previous research on EF in DS by providing an initial description of EF profiles across the lifespan. More longitudinal and behavioural research is needed to further characterise the development of EF in DS.

Post-tooth extraction sepsis without locoregional infection--a population-based study in Taiwan.

OBJECTIVE: To investigate the incidence and risk factors of post-tooth extraction sepsis in patients without locoregional infection. SUBJECTS AND METHODS: We assessed all claim records of the Taiwanese National Health Insurance program in 2005. Admissions for patients aged > or =16 years containing a discharge diagnosis of sepsis, and who received tooth extraction within 14 days before the admission were identified. Patient charts were reviewed to confirm the diagnosis of sepsis and rule out other infection sources. The relationship between postextraction sepsis (PES) and clinical parameters was analyzed. RESULTS: Thirty-three of the 2 223 971 extraction cases met the criteria of PES, an incidence of 1.48 per 100 000, and seven patients (21.2%) died of the disease. Aging significantly increased the risk of PES (P < 0.001). Pre-existing comorbidities were found in 20 of the 33 cases, with diabetes mellitus and hematologic diseases the most common. The method, number, and position of extraction had no influence on PES incidence. Blood cultures were positive in 25 patients (75.8%) and isolates included species of the Streptococcus, Actinomyces, Klebsiella, Bacteroides, Prevotella, and Enterococcus genera. CONCLUSION: Tooth extraction is associated with a low but significant risk of postoperative sepsis, especially in the elderly and patients with underlying diseases.

Cell-mediated immunity and head and neck cancer: with special emphasis on betel quid chewing habit.

Betel quid (BQ) chewing is popular in Taiwan, India, and many southeast-Asian countries. BQ chewing has strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF), and oral cancer (OC). BQ components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in production of antigenicity. BQ ingredients are also shown to induce keratinocyte inflammation by stimulating the production of prostaglandins, TNF-alpha, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in keratinocytes. These events may provoke tissue inflammation, early cell-mediated immunity (CMI), and immune surveillance in BQ chewers. However, BQ components also directly affect the functional activities of immunocompotent cells, and moreover tumor cells may hypo-respond to the CMI via diverse mechanisms such as induction of apoptosis of lymphocytes, induction of production of suppressor T cells, downregulation of MHC molecules in tumor cells, etc. Clinically, an alteration in lymphocyte subsets, a decrease in total number of lymphocytes, and a reduction in functional activities of CMI have been observed in isolated peripheral blood mononuclear cells (PBMC) and tumor infiltrated lymphocytes (TIL) in patients with OSF, OL or OC. Adaptation of tumor cells to immune system may promote clonal selection of resistant tumor cells, leading to immune tolerance. Future studies on effects of BQ components on CMI and humoral immunity in vitro and in vivo can be helpful for chemoprevention of BQ-related oral mucosal diseases. To elucidate how virus infection, tobacco, alcohol and BQ consumption, and other environmental exposure affect the immune status of patients with oral premalignant lesions or OC will help us to understand the immunopathogenesis of OC and to develop immunotherapeutic strategies for OC.

Reactive oxygen species are crucial for hydroxychavicol toxicity toward KB epithelial cells.

Betel quid (BQ) chewing shows a strong correlation to the incidence of oral submucous fibrosis (OSF), leukoplakia and oral cancer. BQ contains mainly areca nut, lime, Piper betle leaf (PBL) and the inflorescence of P. betle (IPB). Hydroxychavicol (4-allyl-catechol, HC), as a major phenolic compound in PBL and IPB, is shown to induce oxidative stress, glutathione (GSH) depletion and cell cycle deregulation. Using bivariate BrdU/PI flow cytometry, KB cells in DNA synthesis (S phase) are shown to be sensitive to the toxic effect of HC and show cell cycle arrest and apoptosis following exposure to 0.1 and 0.3 mM HC. HC-induced apoptosis and cell cycle arrest are associated with mitochondrial membrane potential (delta Psim) depolarization as revealed by a decrease in rhodamine fluorescence. N-acetyl-L-cysteine (1 mM), superoxide dismutase (100 U/ml) and catalase (1000 U/ml) were effective in prevention of HC-induced GSH depletion (as indicated by chloromethylfluorescein fluorescence), reactive oxygen species (ROS) production (by dichlorofluorescein fluorescence), cell cycle arrest and apoptosis. However, dimethylthiourea (2 mM), neocuproine (1 mM), 1,10-phenanthroline (200 microM) and desferrioxamine (0.5 mM) showed little effect on HC-induced cell changes. HC elevated the cellular and mitochondrial GSH levels at moderate concentrations (0.05-0.1 mM), whereas at a concentration of 0.3 mM, inhibitory effects were noted. These results indicate that HC consumption may be associated with BQ-chewing-related oral mucosal diseases via GSH depletion, ROS production, mitochondrial dysfunction, cell cycle disturbance and the induction of apoptosis. These events are related to the production of superoxide radicals and hydrogen peroxide.

Prevention of the areca nut extract-induced unscheduled DNA synthesis of gingival keratinocytes by vitamin C and thiol compounds.

There are about 600 million betel quid (BQ) chewers in the world. BQ chewing is the major risk factor of oral cancer in India, Taiwan, South Africa and numerous other countries. Areca nut (AN) extract, the main component of BQ, exerts cytotoxicity and genotoxicity to several types of cells. In the present study, AN extract induced the unscheduled DNA synthesis (UDS) of gingival keratinocytes (GK). Vitamin C, at concentration of 50 and 200 microg/ml prevented the AN-induced UDS by 41 and 56%, respectively. Glutathione (GSH, 1-3 mM) and N-acetyl-L-cysteine (NAC, 1-3 mM) also protected the AN-induced UDS by 89-100 and 76-90%. These preventive effects were not due to cytotoxicity as analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Deferoxamine (20 and 30 mM), an iron chelator and a free radical scavenger, also prevented AN extract induced UDS of GK by 30-55%. On the contrary, banthocuproine (50-200 microM, a copper chelator) and 1,10-phenanthroline (50, 100 microM, a lipid permeable iron chelator), lacked preventive effects. Specific reactive oxygen species scavengers such as dimethyl-sulfoxide (2%), mannitol (10-20 mM), dimethylthiourea (10-20 mM), pyruvate (10 mM), catalase (200 and 400 U/ml), and superoxide dismutase (50 and 200 U/ml) also lacked these preventive effects. Moreover, higher concentrations of H(2)O(2) (0.5-1 mM) inhibited the basal levels of UDS by 19-37%. Interestingly, NAC, GSH, Vitamin C and deferoxamine cannot prevent the AN-induced morphological changes of GK at similar concentrations. These results reveal that AN extract-induced UDS of GK is associated with free radical reactions. Possibly different ingredients of AN is responsible for genotoxicity and cytotoxicity. Vitamin C, GSH and NAC may be potentially used in the future for chemoprevention of BQ chewing related oral mucosal lesions.

Inducing the cell cycle arrest and apoptosis of oral KB carcinoma cells by hydroxychavicol: roles of glutathione and reactive oxygen species.

Hydroxychavicol (HC; 10 - 50 microM), a betel leaf component, was found to suppress the 2% H(2)O(2)-induced lucigenin chemiluminescence for 53 - 75%. HC (0.02 - 2 microM) was also able to trap superoxide radicals generated by a xanthine/xanthine oxidase system with 38 - 94% of inhibition. Hydroxyl radicals-induced PUC18 plasmid DNA breaks was prevented by HC (1.6 - 16 microM). A 24-h exposure of KB cells to HC (0.5, 1 mM) resulted in 54 - 74% cell death as analysed by a 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. HC (10, 50 microM) further suppressed the growth of KB cells (15 and 76%, respectively). Long-term colony formation of KB cells was inhibited by 51% with 10 microM HC. Pretreatment of KB cells with 100 microM HC inhibited the attachment of KB cells to type I collagen and fibronectin by 59 and 29%, respectively. Exposure of KB cells to 0.1 mM HC for 24 h resulted in cell cycle arrest at late S and G2/M phase. Increasing the HC concentration to 0.25 and 0.5 mM led to apoptosis as revealed by detection of sub-G(0)/G(1) peaks with a concomitant decrease in the number of cells residing in late S and G(2)/M phase. Inducing the apoptosis of KB cells by HC was accompanied by marked depletion in reduced form of GSH (>0.2 mM) and the increasing of reactive oxygen species production (>0.1 mM) as analysed by CMF- and DCF-single cell fluorescence flow cytometry. These results indicate that HC exerts antioxidant property at low concentration. HC also inhibits the growth, adhesion and cell cycle progression of KB cells, whereas its induction of KB cell apoptosis (HC>0.1 mM) was accompanied by cellular redox changes.

Repair of oroantral communications in the third molar region by random palatal flap.

Various palatal flap procedures based on the greater palatine vessels have been advocated for the repair of oroantral communications (OACs). However, when the defect is located in the third molar region, difficulty is encountered in using the palatal flap because rotation is hindered by the vascular pedicle. In this study, we used random palatal flaps to repair OACs in the third molar area in 21 patients. The vascular pedicles were ligated and severed in all cases in order to evaluate whether it was necessary to preserve the greater palatine vessels when using the palatal rotation flap (PRF). The repair was successful in 16 cases (76.2%). The length/width ratio of the flap was the most important factor determining the outcome. The ratios were 2.23 +/- 0.12 and 2.40 +/- 0.14 in the success and failure groups, respectively and their difference was statistically significant (P<0.05). Other clinical parameters such as age, gender, antral infection, tooth displacement into the sinus and duration of the communication had no influence on the outcome (P>0.05). The study showed that the PRF with the appropriate length/width ratio can safely be used in a random fashion. This provided another option in the repair of oroantral communications of difficult locations such as in the tuberosity area.

Areca nut extract and arecoline induced the cell cycle arrest but not apoptosis of cultured oral KB epithelial cells: association of glutathione, reactive oxygen species and mitochondrial membrane potential.

There are 600 million betel quid (BQ) chewers in the world. BQ chewing is a major etiologic factor of oral cancer. Areca nut (AN) and arecoline may inhibit the growth of oral mucosal fibroblasts (OMF) and keratinocytes. In this study, AN extract (100-800 microg/ml) and arecoline (20-120 microM) inhibited the growth of oral KB cells by 36-90 and 15-75%, respectively. Exposure to arecoline (> 0.2 mM) for 24 h induced G(2)/M cell cycle arrest of OMF and KB cells. Areca nut extract (> 400 microg/ml) also induced G(2)/M arrest of KB cells, being preceded by S-phase arrest at 7-h of exposure. No evident sub-G(0)/G(1) peak was noted. Marked retraction and intracellular vacuoles formation of OMF and KB cells were observed. Glutathione (GSH) level, mitochondrial membrane potential (Deltabetam) and H(2)O(2) production of KB cells were measured by flow cytometry. GSH level [indicated by 5-chloromethyl-fluorescein (CMF) fluorescence] was depleted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml), with increasing the percentage of cells in low CMF fluorescence. By contrast, arecoline (0.1-1.2 mM) and AN extract (800-1200 microg/ml) induced decreasing and increasing H(2)O(2) production (by 2',7'-dichloro- fluorescein fluorescence), respectively. Hyperpolarization of Deltabetam (increasing of rhodamine uptake) was noted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml). AN extract (100- 1200 microg/ml) and arecoline (0.1-1.2 mM) induced little DNA fragmentation on KB cells within 24 h. These results indicate that AN ingredients are crucial in the pathogenesis of oral submucous fibrosis (OSF) and oral cancer by differentially inducing the dysregulation of cell cycle control, Deltabetam, GSH level and intracellular H(2)O(2) production, these events being not coupled with cellular apoptosis.

Role of areca nut in betel quid-associated chemical carcinogenesis: current awareness and future perspectives.

Betel quid (BQ)-chewing is a popular oral habit with potential links to the occurrence of oral cancer. Many of the literature-based studies reveal that areca nut (AN) extract may demonstrate mutagenic and genotoxic effects, in addition to inducing preneoplastic as well as neoplastic lesions in experimental animals. Areca nut should, thus, be highly suspected as a human carcinogen. Toxicity studies relating to AN-contained polyphenols and tannins are not conclusive, with both carcinogenic and anti-carcinogenic effects being reported. The mutagenicity and genotoxicity of areca alkaloids has been detected by many short-term assays. However, their genotoxicity to oral fibroblasts and keratinocytes, the target cells of BQ, has not been identified. It would thus appear that AN toxicity is not completely due to its polyphenol, tannin and alkaloid content. The single agent which is responsible for AN carcinogenicity awaits further clarification. Reactive oxygen species produced during auto-oxidation of AN polyphenols in the BQ-chewer's saliva, are crucial in the initiation and promotion of oral cancer. Nitrosation of areca alkaloids also produces AN-specific nitrosamines, that have been demonstrated to be mutagenic, genotoxic and are capable of inducing tumors in experimental animals. Arecaidine and AN extract are further suggested to be tumor promoters. Antioxidants such as glutathione and N-acetyl-L-cysteine can potentially prevent such AN-elicited cytotoxicity. Further studies are needed to delineate the metabolism of AN ingredient and their roles in the multi-step chemical carcinogenesis, in order to enhance the success of the future chemoprevention of oral cancer and oral submucous fibrosis.

Association between genetic polymorphism of tumor necrosis factor-alpha and risk of oral submucous fibrosis, a pre-cancerous condition of oral cancer.

Many cytokines have been thought to play important roles in the pathogenesis of oral submucous fibrosis (OSF), an areca nut chewing-specific pre-cancerous condition characterized by the deposition of collagen in oral submucosa. Tumor necrosis factor-alpha (TNF-alpha), situated in the class III region of human leukocyte antigen (HLA), is a mediator with multiple functions, including the regulation of inflammatory reaction and transcriptions of collagen and collagenase. In total, 809 male subjects were recruited for assessment of the association of OSF with a bi-allelic promoter-region (-308) polymorphism on the TNFA gene. The high production allele, TNF2, was significantly lower among OSF subjects (n = 166) than in areca-chewing controls (n = 284). This association was independent of oral cancer status. The multivariate-adjusted odds ratio for the TNFA 11 genotype was 2.6 (95% confidence interval = 1.4-4.9; p = 0.004). The finding may imply a multifunctional etiological factor of TNF-alpha in OSF pathogenesis.

Expression of proliferating cell nuclear antigen (PCNA) in oral submucous fibrosis, oral epithelial hyperkeratosis and oral epithelial dysplasia in Taiwan.

To test whether the oral epithelia of oral submucous fibrosis (OSF), epithelial hyperkeratosis (EH) and epithelial dysplasia (ED) may have increased proliferative activity under the long-term exposure to areca quid ingredients and whether there is an increased expression of proliferating cell nuclear antigen (PCNA) in oral premalignant lesions with disease progression, we used an immunohistochemical technique with the mouse monoclonal antibody PC10 to investigate PCNA expression in histologic sections of OSF, EH, ED and normal oral mucosa (NOM). Positive PCNA staining was found mainly in basal and parabasal epithelial cells in all specimens of OSF, EH, ED and NOM. The mean PCNA labeling indices (LI) in NOM, OSF, EH and ED were 8.8+/-2.7%, 22.1+/-12.5%, 25.5+/-5. 2% and 44.9+/-15.4%, respectively. Significant differences in the PCNA LI were noted between NOM and OSF (P<0.01), EH (P<0.001) or ED (P<0.001), as well as between ED and OSF (P<0.001) or EH (P<0.01). The gradual increase of PCNA expression with the morphologic transformation of normal epithelial cells into dysplastic epithelial cells suggests that there is increased proliferative activity in oral premalignant lesions with disease progression. However, no significant correlation was found between PCNA LI in OSF epithelium and the clinicohistologic parameters of OSF. In addition, the mean PCNA LI of p53-positive OSF cases (23.7+/-12.0%) was very close to that of p53-negative OSF cases (23.9+/-13.1%), suggesting that there was no association between PCNA and p53 expression in OSF.

Risk factors for leukoplakia and malignant transformation to oral carcinoma: a leukoplakia cohort in Taiwan.

The effects of betel nut chewing, smoking and alcohol on the occurrence of leukoplakia and its malignant transformation to oral carcinoma were quantified in a leukoplakia cohort (n = 435) from one medical centre between 1988 and 1998 in Taiwan. Sixty oral carcinomas were ascertained in this cohort. A case-control study within the leukoplakia cohort was used to study, risk factors. Using the Weibull survival model, the incidence of malignant transformation of leukoplakia was shown to increase with follow-up years. After adjustment for other relevant risk factors, betel nut chewing (adjusted odds ratio (OR) = 4.59; 95% confidence interval (CI) 1.25-16.86) remained a significant risk factor for malignant transformation. Results from the case-control study showed that the adjusted odds ratios for betel nut chewing and smoking on the occurrence of leukoplakia were 17.43 (95% CI 1.94-156.27) and 3.22 (95% CI 1.06-9.78), respectively. Similar findings were observed when daily frequency and duration were taken into account. This implies that cessation of smoking may reduce by 36% leukoplakia cases, while elimination of betel nuts may prevent 62% of leukoplakia and 26% of malignant transformation to oral carcinoma in the underlying population.

Areca nut extract up-regulates prostaglandin production, cyclooxygenase-2 mRNA and protein expression of human oral keratinocytes.

There are about 600 million betel quid (BQ) chewers in the world. BQ chewing is associated with increased incidence of oral cancer and submucous fibrosis. In this study, areca nut (AN) extract (200-800 microg/ml) induced the prostaglandin E(2) (PGE(2)) production by 1. 4-3.4-fold and 6-keto-PGF(1 alpha) production by 1.1-1.7-fold of gingival keratinocytes (GK), respectively, following 24 h of exposure. Exposure of GK to AN extract (>400 microg/ml) led to cell retraction and intracellular vacuoles formation. At concentrations of 800 and 1200 microg/ml, AN extract induced cell death at 21-24 and 32-52% as detected by MTT assay and cellular lactate dehydrogenase release, respectively. Interestingly, AN-induced morphological changes of GK are reversible. GK can still proliferate following exposure to AN extract. Cytotoxicity of AN extract cannot be inhibited by indomethacin (1 microM) and aspirin (50 microM), indicating that prostaglandin (PG) production is not the major factor responsible for AN cytotoxicity. PGE(2) exhibited little effect on the growth of GK at concentrations ranging from 100-1000 pg/ml. Stimulating GK production of PGs by AN extract could be due to induction of cyclooxygenase-2 (COX-2) mRNA expression and protein production. These results suggest that AN ingredients are critical in the pathogenesis of oral submucous fibrosis and oral cancer via their stimulatory effects on the PGs, COX-2 production and associated tissue inflammatory responses. AN cytotoxicity to GK is not directly mediated by COX-2 stimulation and PG production.

Expression of p53 protein in oral submucous fibrosis, oral epithelial hyperkeratosis, and oral epithelial dysplasia.

BACKGROUND AND PURPOSE: In our previous study, positive p53 staining was observed in 47 of 81 (58%) cases of oral squamous cell carcinoma associated with areca quid (AQ) chewing and cigarette smoking. This study looked for expression of p53 protein in premalignant oral lesions in patients who chewed AQ or smoked cigarettes, or both. METHODS: Expression of p53 protein was examined in histologic sections of oral submucous fibrosis (OSF, n = 50), epithelial hyperkeratosis (EH, n = 10), epithelial dysplasia (ED, n = 10), and normal oral mucosa (NOM, n = 10) with antibodies against p53 protein using an immunoperoxidase technique. RESULTS: Positive p53 staining was observed in 30 (60%) OSF specimens, four (40%) EH specimens, seven (70%) ED specimens, and none of the NOM specimens. Only four (8%) of the OSF specimens and none of the EH specimens had more than 25% p53-positive keratinocytes. However, in four (40%) of the ED specimens, more than 50% of the keratinocytes were p53-positive. The degree of p53 staining increased with the morphologic transformation of normal-appearing epithelial cells into dysplastic epithelial cells. There was no significant correlation between expression of p53 in OSF epithelium and the clinicohistologic parameters of patients with OSF. CONCLUSIONS: These results demonstrate that p53 is often present in precancerous lesions of patients who chew AQ and smoke cigarettes. We suggest that p53 may play a role in dysplastic cell transformation in premalignant oral lesions.

Arecoline cytotoxicity on human oral mucosal fibroblasts related to cellular thiol and esterase activities.

Betel quid (BQ) chewing is associated with an increased risk of oral submucous fibrosis (OSF) and oral cancer in India and many south-east Asian countries. Recently, we have shown that arecoline is cytotoxic to cultured human oral mucosal fibroblasts. This study investigated protective effects of various agents against the cytotoxicity of arecoline and its mechanisms. Arecoline, at concentrations of 0.2 and 0.4 mM, decreased the cell numbers by 38% and 63%, respectively. At a concentration of 2 mM, N-acetyl-L-cysteine [a glutathione (GSH) synthesis precursor] could prevent arecoline-induced cytotoxicity. The decrease in cell numbers was reduced to 17% relative to control. Extracellular addition of esterase at a concentration of 0.1 U/ml could almost completely protect the oral mucosal fibroblast (OMF) from arecoline-induced cytotoxicity. Arecoline is a muscarinic receptor agonist. However, atropine, a muscarinic receptor antagonist was unable to protect the cells from arecoline cytotoxicity at a concentration of 10 microM. Pretreatment of OMF with 50 microM buthionine sulfoximine (a cellular GSH synthesis inhibitor) or 0.5 mM diethylmaleate (a cellular GSH depleting agent) potentiated the cytotoxic effects of arecoline. These results indicate that cytotoxicity of arecoline on OMF is associated with cellular GSH levels and esterase activities. Factors that induce the GSH synthesis or esterase activity of oral mucosal cells can be used for future chemoprevention of BQ chewing-related lesions.

Expression of cyclin D1 is correlated with poor prognosis in patients with areca quid chewing-related oral squamous cell carcinomas in Taiwan.

Abnormal expression of cell cycle regulatory proteins, particularly cyclin D1, has been implicated in the pathogenesis of several types of cancer. We have examined the expression of cyclin D1 in histological sections of oral squamous cell carcinomas (SCCs) using anti-cyclin D1 antibodies with an immunoperoxidase technique. Cyclin D1 nuclear staining was observed in 73 of 88 (83%) cases of oral SCC. In 54 of these 73 (74%) cases, positive cyclin D1 staining was also found in the normal appearing epithelium immediately adjacent to the cyclin D1-positive SCCs. No significant correlation was found between the expression of cyclin D1 and the patients' age, sex, oral habits, cancer location and STNM status. The Kaplan-Meier analysis showed that patients with tumors containing more than 10% cyclin D1-positive cells had significantly shorter overall survival than those with tumors containing less than 10% cyclin D1-positive cells or with cyclin D1-negative tumors (P<0.05). Patients with positive lymph node status also had significantly shorter overall survival (P<0.01). These results indicate that cyclin D1 may play an important role in the genesis of oral SCC and may serve as an adjuvant marker of worse prognosis in patients with oral SCCs in Taiwan.

Automatic three-dimensional multimodality registration using radionuclide transmission CT attenuation maps: a phantom study.

UNLABELLED: Coregistration of images from a single subject, acquired by different modalities, is important in clinical diagnosis, surgery and therapy planning. The purpose of this study was to evaluate, using a physical torso phantom, a novel, fully automated method for three-dimensional image registration of CT and SPECT, using radionuclide transmission (RNT) attenuation maps. METHODS: We obtained CT scans and SPECT scans paired with RNT maps of an anthropomorphic cardiac phantom. RNT attenuation maps were acquired using an uncollimated 99mTc-filled flood source. RNT and SPECT scans were acquired in the same spatial orientation (usual clinical practice in nonuniform attenuation correction). In addition, CT attenuation maps (CTMAPs) for 99mTc SPECT were generated from CT by linear energy scaling. RNT maps were registered to CT and CTMAPs by iterative simplex minimization of count difference and uniformity index (sum of RNT map intensity variances corresponding to each intensity level in the CT volume). In each iteration, three shifts and three angles were adjusted. To register SPECT to CT, we applied the RNT transformation parameters to SPECT. RESULTS: RNT maps could be registered to CT and CTMAP images using both criteria. The average three-dimensional distance between landmark and automated registration was 2.5 +/- 1.2 mm for count difference and 3.3 +/- 1.3 mm for uniformity index. The three-dimensional reproducibility errors were 1.2 +/- 0.7 mm for count difference, 2.1 +/- 0.5 mm for uniformity index and 2.3 +/- 1.0 mm for manual marker registration. The minimization of uniformity index was robust when up to 50% CT or RNT slices were missing and was not affected significantly (<2 mm) by realistic variation in CT values (+/- 12 Hounsfield units). CONCLUSION: In addition to typical use in nonuniform attenuation correction, RNT maps can be used for fully automated three-dimensional registration of SPECT to CT. Such registration is not affected by features and quality of SPECT images and avoids difficulties associated with fiducial markers. Our method can be applied to SPECT-CT registration of various organs, such as brain, heart, lungs, breasts and abdomen, including oncological scans.

Effects of areca nut, inflorescence piper betle extracts and arecoline on cytotoxicity, total and unscheduled DNA synthesis in cultured gingival keratinocytes.

Betel quid (BQ) chewing has a strong correlation with oral leukoplakia, submucous fibrosis and oral cancer. For elucidation of its pathogenesis, we investigated the effects of areca nut (AN) and inflorescence piper betle (IPB) extracts and arecoline on the growth, total DNA synthesis (TDS) and unscheduled DNA synthesis (UDS) of cultured human gingival keratinocytes (GK). Arecoline and AN extract suppressed the growth of GK over 5 days of incubation in a dose-dependent fashion. At concentrations of 100, 200 and 400 microg/ml, AN extract suppressed the growth of GK by 31%, 46% and 90%, respectively. The IPB extracts exerted less inhibitory effect on the growth of GK. IPB extract (200-400 microg/ml) decreased cell numbers by 20-40% over 5 days of incubation. Moreover, at a concentration of 0.1, 0.2 and 0.4 mM, arecoline suppressed cell growth by 44%, 77% and 96%, respectively. However, only AN extract induced TDS and UDS in cultured GK within 6 h of exposure. Induction of UDS by AN extract was concomitant with the presence of apparent intracellular vacuolization. Arecoline was also toxic to GK, but did not induce intracellular vacuolization. At a concentration range of 200-1600 microg/ml, AN extract induced TDS by 2.1- to 6.5-fold. Furthermore, at a concentration of 400-1600 microg/ml, AN extract elevated the UDS by 2.4- to 5.5-fold more than that of untreated control. On the contrary, IPB extract (200-1600 microg/ml) and arecoline (0.2-1.6 mM) inhibited the TDS and UDS of GK to a different extent. Simultaneous exposure of confluent GK to AN extract, IPB extract and arecoline for 1 to 5 days led to different degrees of cytotoxicity that was dose- and time-dependent. These results indicate that AN, IPB and arecoline take part in the pathogenesis of BQ chewing-related oral mucosal lesions, possibly through both genotoxic and non-genotoxic mechanisms.

Expression of p53 protein correlates with decreased survival in patients with areca quid chewing and smoking-associated oral squamous cell carcinomas in Taiwan.

Expression of p53 protein was examined in oral squamous cell carcinoma (SCC) from patients who were areca quid (AQ) chewers and/or tobacco smokers, using anti-p53 antibodies with an immunoperoxidase technique. Positive p53 stain was observed in 47 of 81 (58%) cases of oral SCC. p53 overexpression was found to be higher in patients without AQ chewing and smoking habits than in patients with these two habits (80% vs 52%, P=0.076). No significant correlation was found between p53 expression and the patients' age, sex, cancer location, clinical staging, primary tumor TNM status, or histological differentiation of SCC. The Kaplan-Meier analysis showed that the prognosis for patients with p53-negative tumors was significantly better than that for patients with p53-positive tumors (P<0.05). A significant correlation was also observed between positive lymph node status and poor prognosis (P<0.05). These results suggest that p53 may serve as an adjuvant marker of poor survival in patients with oral SCCs in Taiwan.