Evaluation of oxidative stress and nitric oxide levels in patients with oral cavity cancer

OBJECTIVE

The aim of this study was to evaluate the magnitude of oxidative stress and levels of nitric oxide in patients with oral cavity cancer by analyzing the levels of lipid peroxidation products, antioxidants and nitric oxide products.

METHODS

This prospective study was conducted on 15 patients with biopsy proven squamous cell cancer of the oral cavity with clinical stage III/IV and an equal number of age and sex matched healthy subjects. The levels of lipid peroxidation products, antioxidants and nitric oxide products were determined by colorimetric methods.

RESULTS

Lipid peroxidation products like lipid hydroperoxide (LHP) and malondialdehyde (MDA) and nitric oxide products like nitrite (NO(2)(-)), nitrate (NO(3)(-)) and total nitrite (TNO(2)(-)) were significantly elevated, whereas enzymatic and non-enzymatic antioxidants were significantly lowered in oral cavity cancer patients when compared to normal healthy subjects.

CONCLUSIONS

Enhanced lipid peroxidation with concomitant decrease in antioxidants is indicative of oxidative stress that provides evidence of the relationship between lipid peroxidation and oral cavity cancer. Increased nitric oxide production represents a general mechanism in its pathogenesis.

Loss of heterozygosity at 9q33 and hypermethylation of the DBCCR1 gene in oral squamous cell carcinoma

The DBCCR1 gene at chromosome 9q33 has been identified as a candidate tumour suppressor, which is frequently targeted by promoter hypermethylation in bladder cancer. Here, we studied the possible involvement of DBCCR1 in the development of oral squamous cell carcinoma. DNA from 34 tumours was examined for loss of heterozygosity (LOH) at three markers surrounding DBCCR1 and for hypermethylation of the DBCCR1 promoter, using methylation-specific PCR and methylation-specific melting-curve analysis. LOH was found in 10 of 31 cases (32%), and DBCCR1 hypermethylation was present in 15 of 34 cases (44%). Hypermethylation of DBCCR1 was also present in three of seven epithelial tissues adjacent to the tumours, including two hyperplastic and one histologically normal epithelia. Furthermore, of four oral leukoplakias with dysplasia, one showed LOH at 9q33 and two showed DBCCR1 hypermethylation. These data suggest that LOH at 9q33 and hypermethylation of the DBCCR1 promoter are frequent and possibly early events in oral malignant development.

Masticatory efficiency before and after surgery in oral cancer patients: comparative study of glossectomy, marginal mandibulectomy and segmental mandibulectomy

This study evaluated the effect of oral cancer surgery on masticatory efficiency. Masticatory efficiency was measured using the ATP absorption method. Eating ability was measured using a questionnaire. Two groups were employed as controls: The "normal occlusion group" consisted of subjects who had a complete set of natural maxillary teeth opposed to mandibular teeth, and the "unilateral occlusion group" consisted of subjects who had lost their molar and premolar teeth on one side of the mandible as a result of caries or periodontal diseases. Three treatment groups, each of 6 patients, were studied: a glossectomy group, a marginal mandibulectomy group and a segmental mandibulectomy group. There were no differences in masticatory efficiency between two control groups. Masticatory efficiencies of the three oral cancer treatment groups were lower than in the unilateral occlusion group, even 12 months after surgery. Masticatory efficiency of the glossectomy group was significantly higher 12 months after surgery compared with pre-surgery. Masticatory and eating abilities of the marginal mandibulectomy group and the segmental mandibulectomy were reduced at 3 and 6 months after surgery. The masticatory efficiency 12 months after surgery was higher in the marginal mandibulectomy group than the segmental mandibulectomy group, although the difference was not statistically significant. The self assessed eating ability 12 months after surgery was significantly higher in the marginal mandibulectomy group than the segmental mandibulectomy group. These results suggest that discontinuation of the mandible may lead patients to eat only foods that do not require a substantial amount of chewing. Hence, the quality of life of patients in the marginal mandibulectomy group was considered to be better than that in the segmental mandibulectomy group.

Differential oblique angle spectroscopy of the oral epithelium

Increasing evidence suggests that inflammation may contribute to the process of carcinogenesis. This is the basis of several clinical trials evaluating potential chemopreventive drugs. These trials require quantitative assessments of inflammation, which, for the oral epithelium, are traditionally provided by histopathological evaluation. To reduce patient discomfort and morbidity of tissue biopsy procedures, we develop a noninvasive alternative using diffuse reflectance spectroscopy to measure epithelial thickness as an index of tissue inflammation. Although any optical system has the potential for probing near-surface structures, traditional methods of accounting for scattering of photons are generally invalid for typical epithelial thicknesses. We develop a single-scattering theory that is valid for typical epithelial thicknesses. The theory accurately predicts a distinctive feature that can be used to quantify epithelial thickness given intensity measurements with sources at two different angles relative to the tissue surface. This differential measure approach has acute sensitivity to small, layer-related changes in scattering coefficients. To assess the capability of our method to quantify epithelial thickness, detailed Monte Carlo simulations and measurements on phantom models of a two-layered structure are performed. The results show that the intensity ratio maximum feature can be used to quantify epithelial thickness with an error less than 30% despite fourfold changes in scattering coefficients and 10-fold changes in absorption coefficients. An initial study using a simple two-source, four-detector probe on patients shows that the technique has promise. We believe that this new method will perform well on patients with diverse tissue optical characteristics and therefore be of practical clinical value for quantifying epithelial thickness in vivo.

Increased expression of amyloid precursor protein in oral squamous cell carcinoma

In our previous study, we identified amyloid precursor protein (APP) in an oral squamous cell carcinoma (OSCC)-enriching subtractive hybridization library. Our present study attempts to define the significance of APP expression in the genesis of OSCC. RT-PCR analysis showed increase in APP mRNA expression for more than 2-fold in 76% of OSCC (n = 55) relative to corresponding non-cancerous matched tissues (NCMT). The majority of esophageal SCCs also had increase in APP mRNA expression. OSCC patients exhibiting increase in APP mRNA expression had significantly lower survival rate compared to patients exhibiting the opposite status. Western blotting analysis identified APP751 and APP770 as the major APP isoforms in oral keratinocytes. A high correlation between mRNA and protein expressions of APP was noted in OSCC/NCMT pairs. Immunohistochemistry further showed a remarkable increase of APP in OSCC tissue relative to NCMT. Treatment with an antisense oligonucleotide against APP reduced cellular and secreted APP as well as growth in an OSCC cell line. Our study provides novel clues that APP expression is involved in the proliferation and carcinogenesis of OSCC. Correlated with such pathogenesis was the survival of its victims. The degree of APP expression could serve as an invaluable marker for oral carcinogenesis.

Loss of cyclin E requirement in cell growth of an oral squamous cell carcinoma cell line implies deregulation of its downstream pathway

Cyclin E and Cdk2 have been shown to play an important role in G1/S transition of the cell cycle. Two E-type cyclins (E1 and E2) have been identified to date and share functionally similarities. Upregulation of these cyclins has been observed frequently in human cancers. We examined the expression profile of cyclin E1 and E2 in cell lines derived from human oral squamous cell carcinoma (SCC), and found that the expression of cyclin E1 protein was hardly detected in HSC-2 cells. Although cyclin E2 was abundantly expressed, histone H1 kinase activities of both E-type cyclins were virtually undetectable in this cell line. Inhibition of cyclin E1, but not that of E2, by using vectors expressing antisense-oriented their cDNAs induced drastic growth suppression on HOC313 cells that express both E-type cyclins. Inhibition of neither cyclin E1 nor E2 suppressed the growth of HSC-2 cells, and compensatory elevation of cyclin E1 was not evident in cyclin E2-inhibited HSC-2 cells. In contrast, HSC-2 cells expressed cyclin D1 and hyperphosphorylated forms of Rb family proteins, and were arrested in G1 by overexpression of p16(INK4), a specific inhibitor against D-type cyclin activity. These results indicate that HSC-2 cells lost proper growth control specifically mediated by cyclin E and suggest that deregulation of its downstream pathway may contribute to tumorigenesis of oral SCC.

The role of apoptosis in oral disease: mechanisms; aberrations in neoplastic, autoimmune, infectious, hematologic, and developmental diseases; and therapeutic opportunities

Apoptosis is a genetically programmed form of cell death, which primarily functions to eliminate senescent or altered cells that are useless or harmful for the multicellular organism. Contrary to necrosis, apoptosis represents a physiologic cellular mechanism, normal function and control of which are critical for the development and homeostasis of multicellular organisms. In contrast, aberrations of the apoptotic mechanisms that cause excessive or deficient programmed cell death have been linked to a wide array of pathologic conditions. This review briefly summarizes the major apoptotic pathways and molecules and presents the most important oral diseases that are related to dysregulation of apoptosis. Knowledge of the association between aberrations in apoptotic mechanisms and human pathology hopefully will be implemented for the design of improved diagnostic and prognostic assays and the development of novel, more efficient, therapeutic strategies.

Functional differences between integrin alpha4 and integrins alpha5/alphav in modulating the motility of human oral squamous carcinoma cells in response to the V region and heparin-binding domain of fibronectin

The high-affinity heparin-binding domain and the V region of fibronectin (FN) mediate invasion and migration of human oral squamous cell carcinoma (SCC) cells. We investigated the role of the alpha4, alpha5, and alphav integrin receptors--which are central to mediating interactions with these domains of FN--in regulating SCC cell migration. SCC cells expressed the alpha4, alpha5, and alphav integrin subunits on their surface, although alpha4 expression was low. Treatment with recombinant FN proteins containing an alternatively spliced V region (V+) and either an unmutated (H+) or a mutated, nonfunctional high-affinity heparin-binding domain (H-) increased expression of alpha5 and alphav and cell motility. Antisense alpha5 or alphav oligonucleotides inhibited cell motility stimulated by FN proteins, as did blocking antibodies to alpha5 or alphav. Blocking antibodies to alpha5 increased alphav and alpha4 levels, and blocking antibodies to alphav increased the levels of alpha5 and alpha4, without increasing cell motility. In contrast, an antisense alpha4 oligonucleotide and alpha4-blocking antibodies increased cell motility, especially migration stimulated by V+H+ and V+H- FN proteins. alpha4-Blocking antibodies alone increased motility, probably by inducing alpha5 and alphav expression. Transfection with alpha4 cDNA decreased cell motility and alpha5 and alphav expression. Thus, the increased motility induced by the FN protein is probably mediated by alphav and alpha5, whereas alpha4 downregulates this process in a transdominant fashion.

Expression of hepatocyte growth factor and c-met protein is significantly associated with the progression of oral squamous cell carcinoma in Taiwan

BACKGROUND

Hepatocyte growth factor (HGF) is a pleotropic growth factor that regulates cell proliferation, migration, survival, tumor angiogenesis, and tumor cell invasion and metastasis. Its diverse biological effects are mediated through its interaction with its receptor, c-met protein.

METHODS

In this study, we examined the expression of HGF and c-met protein in 93 specimens of oral squamous cell carcinoma (OSCC), 10 specimens of oral epithelial dysplasia (OED), 14 specimens of oral epithelial hyperkeratosis (OEH), and 16 specimens of normal oral mucosa (NOM) by immunohistochemistry. The HGF and c-met labeling indices (LIs) in OSCC, OED, OEH, and NOM groups were calculated and compared between groups. The correlation between the expression of HGF or c-met in OSCCs and clinicopathological parameters, or survival of OSCC patients was analyzed statistically to investigate the possible influence of HGF or c-met on the progression and prognosis of OSCCs in Taiwan.

RESULTS

Positive HGF or c-met staining was mainly cytoplasmic. The mean HGF LI increased significantly from NOM (3.1 +/- 5.1%) through OEH (32.5 +/- 19.8%) and OED (52.0 +/- 19.3%) to OSCC (71.9 +/- 28.6%; P = 0.000). The mean c-met LI also increased significantly from NOM (25.8 +/- 30.8%) and OEH (34.4 +/- 19.3%) through OED (53.0 +/- 20.0%) to OSCC (73.0 +/- 29.4%; P = 0.000). Statistical analysis showed that the c-met LI in either the tumor center or invasion front was significantly associated with T status, N status, and clinical staging of OSCC. However, only the HGF LI in the tumor invasion front was significantly correlated with N status and clinical staging of OSCC.

CONCLUSION

Our results suggest that the expression of HGF and c-met protein is an early event in oral carcinogenesis in Taiwan. The HGF LI in the tumor invasion front and the c-met LI in either the tumor center or invasion front can predict the progression of OSCCs in Taiwan.

Oral functional outcome after intraoral reconstruction with nasolabial flaps

In this study, the functional and aesthetic outcome of patients with nasolabial flaps in the floor of the mouth was examined. Sixteen patients underwent reconstruction of the floor of the mouth with 19 nasolabial flaps after resection of a squamous cell carcinoma. Eight patients received postoperative radiotherapy. The patients were questioned concerning oral disabilities. Speech, mastication, deglutition, oral continence and the aesthetic result were evaluated. Two-point discrimination, temperature sensation and blunt-sharp discrimination of the intraoral flaps were tested. Speech and the wearing of dentures were hardly affected. Consumption of solid foods caused moderate problems in half of the patients. No sensibility problems were found. The aesthetic deformity was minimal. The use of nasolabial flaps in patients with limited defects of the anterior floor of the mouth after tumor resection showed adequate functional and aesthetic results.

Induction of apoptosis in oral cancer cells: agents and mechanisms for potential therapy and prevention

Oral cancer is one of the most disfiguring types of cancer, since the surgical removal of the tumor may result in facial distortion. Oral cancer is also known to exhibit "field cancerization", resulting in the development of a second primary tumor. Furthermore, the five-year survival rate of this disease has remained approximately 50% during the past 30 years. Prevention and early detection/treatment of oral cancer could significantly improve the quality of life for individuals at risk. Recently, the targeted elimination of oral squamous cell carcinoma cells by inducing apoptosis has emerged as a valued strategy to combat oral cancer. Studies utilizing a variety of chemical or biological interventions demonstrated promising results for induction of apoptosis in oral malignant cells. This review summarizes the results of a number of investigations focused specifically on induction of apoptosis in oral cancer cells by synthetic compounds and naturally occurring chemopreventive agents with apoptotic potential.

Delivery of 10boron to oral squamous cell carcinoma using boronophenylalanine and borocaptate sodium for boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a unique radiation therapy in which boron compounds are trapped into tumor cells. To determine the biodistribution of boronophenylalanine (BPA) in nude mice carrying oral squamous cell carcinoma (SCC), BPA was administered at a dose of 250 mg/kg body weight intraperitoneally. Two hours later, (10)B concentration in the tumor was 15.96 ppm and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 6.44, 4.19, 4.68 and 4.56, respectively. Two hours after the administration of borocaptate sodium (BSH) at a dose of 75 mg/kg body weight, (10)B concentration in the tumor was 3.61 ppm, and tumor/blood, tumor/tongue, tumor/skin and tumor/bone (10)B concentration ratios were 0.77, 1.05, 0.60 and 0.59, respectively. When cultured oral SCC cells were incubated with BPA or BSH for 2 h and then exposed to thermal neutrons, the proportion of survival cells that were capable of forming cell colonies decreased exponentially, depending on (10)B concentration. BPA-mediated BNCT was more efficient than BSH-mediated BNCT. Addition of boron compounds in the cell suspension during neutron irradiation enhanced the cell-killing effect of the neutrons. These results indicate that BPA is more selectively incorporated into human oral SCC as compared with normal oral tissues, and that both extra- and intra-cellular BPA contribute to the cell-killing effect of BNCT. BPA may be a useful boron carrier for BNCT in the treatment of advanced oral SCC.

Implications of cytokeratin 8/18 filament formation in stratified epithelial cells: Induction of transformed phenotype

The cytokeratin (CK) pair 8 and 18 is normally expressed in all simple epithelia. This pair is not normally seen in stratified epithelial cells. Squamous cell carcinomas derived from stratified epithelia show anomalous expression of this CK pair. It is not known whether CKs 8 and 18 in any way contribute to the malignant phenotype of these cells. We used an immortalised, nontransformed human foetal buccal mucosa (FBM) cell line that expresses significantly higher amounts of CK18 compared to CK8. FBM cells were transfected with the full-length CK8 gene to study the role of CKs 8 and 18 in malignant transformation. Clones with higher expression of CK8 compared to untransfected FBM cells were studied for changes in their phenotypic characteristics. Immunofluorescence studies using antibodies to CKs 8 and 18 revealed well-decorated filaments throughout the cytoplasm in CK8 gene-transfected cells vs. untransfected FBM cells. Transmission images showed that FBM cells were isolated while transfected cells were in groups of well-spread cells with cellular projections. Transfected cells were independent of growth supplement requirements and showed anchorage-independent growth in soft agar assay and significantly reduced doubling time compared to nontransfected FBM cells. DNA flow-cytometric studies revealed increased DNA content and prolonged S phase in transfected clones vs. FBM cells. Injection of cells s.c. obtained from soft agar colonies developed from 2 of the clones resulted in tumour formation at the site of injection. In both cases, lung metastasis was also seen. Thus, in conclusion, it appears that increased expression of CK8 in some way changes the phenotypic characteristics of stratified epithelial cells, resulting in malignant transformation.

Longitudinal health-related quality of life after mandibular resection for oral cancer: a comparison between rim and segment

BACKGROUND

Mandibular resection for oral cancer is often necessary to achieve an adequate margin of tumor clearance. Segmental mandibulectomy has been associated with a poor health-related quality of life (HRQOL), particularly before composite free tissue transfer to reconstruct the defect. Little is published in the literature contrasting the subjective deficit of segmental compared with rim resection. The aim of this study was to use a validated head and neck HRQOL questionnaire to compare rim and segmental mandibular resection in patients having primary surgery for oral cancer.

METHOD

There were 224 consecutive patients between 1995 and 1999 who were treated by primary surgery for oral squamous cell carcinoma. One hundred twenty-tree had no mandibular resection, 44 had a rim resection, and 57 had a segmental resection. The University of Washington Quality of life questionnaire (UW-QOL) was administered before treatment, at 6 months, 12 months and after 18 months.

RESULTS

Preoperatively, patients undergoing segmental resection reported significantly more pain, chewing problems, and a lower composite UW-QOL score. Postoperatively, the segment group tended to score worse at all time points, particularly in appearance, swallowing, recreation, and chewing; however, the difference between rim and segment was only seen in smaller resections without adjuvant radiotherapy. Little difference was seen between rim or segment for tumors < 4 cm with radiotherapy and between rim and segments for tumors > 4 cm.

CONCLUSION

After segmental mandibulectomy and reconstruction using composite free tissue transfer, the UW-QOL scores were relatively good. The only 2 difference between rim and segments was noted in the small resections without radiotherapy, and some of this was reflected in differences at baseline.

[Clinical study of the area under the blood concentration-time curve of targeting intra-arterial infusion chemotherapy with nedaplatin for primary oral cancer]

We treated oral cancer using a targeting intra-arterial infusion chemotherapy with CDGP (nedaplatin); dosages were determined by the original formula. We compared the expected AUC (area under the curve) with the actual AUC in primary oral cancer cases to assess the optimal dosage of CDGP for intra-arterial chemotherapy and to study relevance of AUC, effectiveness of independent chemotherapy and side effects. Eleven cases were treated at the Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa Medical University, from October 1998 to June 2002. The results are as follows. 1) A correlation was seen between the AUC and degree of thrombocytopenia. 2) AUC may reveal renal function, especially for GFR. 3) The response rate of the targeted intra-arterial infusion chemotherapy with CDGP was remarkably high and serious side effects were not observed. It appears that the set-up of the optimum dose should be decided based on the actual AUC. 4) There was about a 4/3 difference between the value of the expected AUC and the actual AUC. The equation for dosages based on the actual AUC needs to be studied further.

Evaluation of quality of life of patients with oral cavity cancer in three counties of south Bulgaria

AIM

To evaluate the quality of life of patients with oral cavity cancer in three counties of South Bulgaria.

MATERIALS AND METHODS

A standard questionnaire was developed to evaluate the social status. Twenty two patients with oral cancer were interviewed (diagnoses by ICD 9th Revision 141-149). SPSS statistical software version 8.0 was used for statistical analysis employing the alternative analysis and ANOVA.

RESULTS AND DISCUSSION

Oral cancer affects 1) mostly men-68.2%, 2) smokers-59.1% (of the people we interviewed, smoking regularly twenty and more cigarettes daily), and 3) people who consume alcohol on regular basis - 40.9% of the interviewees. The life quality of the interviewed people was evaluated on a specially developed five-degree scale. 22.7% of the interviewed people were classified as first scale group characerised with speaking and alimentary disorders, impaired aesthetics and pains in the oral cavity. 36.4% were scored as the second scale group--these had speaking disorders and disorders of the alimentary tract, oral cavity pain without impairment of the orofacial aesthetics. 27.3% were classified as third scale group in which the patients had only two functions impaired. Group five contained 4.5% of all patients with no manifest disorders.

CONCLUSIONS

The results suggest that oral cancer patients need a lot of prosthetic care to mend their oral defects and a lot of rehabilitation to restore their ability to function socially, a task which must be realized by a rehabilitation team including the general dental practitioner.

Indications for vascularized free rectus abdominis musculocutaneous flap in oromandibular region in terms of efficiency of anterior rectus sheath

The anterior rectus sheath, efficacious in reconstructive surgery, is used in oromandibular reconstruction with the free rectus abdominis musculocutaneous flap. This study describes reconstruction with this sheath in 20 patients: to preserve only the swallowing function in 10 patients (formation of the bulge of the reconstructed oral floor and prevention of its sinking); to preserve both swallowing and articulation in 5 patients (formation of the bulge of the reconstructed tongue and prevention of its sinking, concurrent with a money-pouch-like reconstruction of the tongue, laryngeal suspension, and neuroanastomosis); and to prevent exposure of the reconstruction plate, replacing the resected mandibular continuity in 5 patients. The purpose of reconstruction was achieved in all patients. The vascularized free rectus abdominis musculocutaneous flap with a firm anterior rectus sheath may be the first choice for these types of reconstruction.

Speech evaluation and swallowing ability after intra-oral cancer

In this study, four methods of postoperative speech evaluation are compared for 19 persons with oral cancers who have undergone oral surgery and/or radiotherapy. The Munich Intelligibility Profile was used for intelligibility testing and semiquantitative scoring by novice listeners. Expert ratings were done on the Therapy Outcome Measure (TOM) Phonological Disability form. For self-evaluation, the EORTC QLQ-C30 and the Head and Neck module was used. Swallowing function was scored on the TOM Dysphagia form. There was a high intercorrelation between the results of subjective speech evaluation by experts and non-experts and the intelligibility test, but no correlation with any of these methods could be shown for the self-evaluation by the participants. Voice quality seemed to have an influence on non-expert scores. Swallowing was a more severe problem for our group than speech impairment.

Repair of anterior floor of mouth defects by a central or paramedian island tongue flap

One method for restoring the anterior floor of mouth defects resulting from T(1) and especially T(2) cancer excision involves the creation of a myomucosal island flap from the dorsal median portion of the tongue and transferring it as a transit flap to the floor of the mouth. We are not the first to advocate this method. In this paper we present a previously unreported, slightly modified technique utilizing this tongue flap. The modification consists of a 90 degrees twisting of the flap to achieve a more appropriate adaptation to the defect. In the case of spreading carcinoma from the floor of the mouth to the central portion of the tongue, a similar paramedian one-sided tongue flap was created instead of a central island tongue flap. Our present experience consists of a small series of 12 patients. The procedures were successful in all patients. No remarkable disturbances of speech or deglutition were observed in any of the patients. There were two complications: one haematoma and one partial necrosis of the tip of the tongue. In our opinion, the reconstruction of the anterior floor of mouth defects using a central island tongue flap has not gained the popularity it deserves.

Do multiple consecutive head and neck reconstructions improve the patients functional outcome?

BACKGROUND

The purpose of this study was to determined the functional outcome of surgically treated head and neck cancer patients who required more than "standard" microsurgical reconstruction.

METHODS

Data concerning all patients with head and neck cancers, who underwent free-tissue transfers in our institution between January 1, 1994 and August 31, 1999 were reviewed. The cases of tumor recurrences and those with micro-surgical complications were excluded. Among 68 primary microsurgical reconstructions, we identified five cases where limitations in speech and/or swallowing required additional flap procedures. An objective assessment of speech and swallowing could be performed in four patients.

RESULTS

In these five patients up to three consecutive additional procedured including three free-tissue transfers in one case, had to be performed mainly because of secondary contraction of the surrounding irradiated tissue. A total of 13 pedicled and free flaps were transferred to the head and neck. Three patients underwent two consecutive free tissue transfers. The additional reconstructions were requested to improved tongue mobility in three patients and to enlarge the upper digestive tract in two patients. The mean follow-up was 23 months (range : 9-53 months). Functional evaluation was rated average in three patients and poor in one patient. One patient died before functional evaluation could be performed because of disease. The four patients judged the final cosmetic result as satisfactory.

CONCLUSION

We report five cases of head and neck microsurgical reconstructions where additional flap procedures were requested because of inadequately restored speech or nutrition capabilities. We show that, maybe because of extensive fibrosis, only limited improvement in the functional outcome can be expected despite the use of even sophisticated microsurgical reconstructions. This paper supports the idea that every effort should be put in the initial reconstruction, as further procedures are of poor functional prognosis.

Quantification of doxorubicin and validation of reversal effect of tea polyphenols on multidrug resistance in human carcinoma cells

HPLC was used to analyze doxorubicin in multidrug-resistance (MDR) human carcinoma cells. This method is novel, simple, sensitive, linear, accurate and precise. The minimal detectable concentration is 0.2 microg ml(-1). The reversal effects of tea polyphenols on MDR are elucidated by this method. The results indicate that the tea polyphenol, (-)-epigallocatechin gallate, is a potential modulator of MDR.

[Transfection of the nm23-H1 gene into BcaCD885 cell line inhibits the potential of invasion, adhesion and mobility]

OBJECTIVE

To transfect nm23-H1 into the BcaCD885 cell lines in order to get safe high-efficiency and low-toxicity, and to find out whether nm23-H1 could affect the invasion and metastases ability of BcaCD885 cell lines.

METHODS

Lipofect was used to transfect nm23-H1 into BcaCD885 cell lines; immunohistochemistry was used to detect the difference expression of nm23-H1 between transfected and non-transfected cell lines; then transwell-room and wash way were used to detect the difference of invasion and metastases ability between transfected and non-transfected cell lines.

RESULTS

PCMV-NEO-BAM system gave the stability expression of nm23-H1; there was significant different NDPKA expression between transfected and non-transfected BcaCD885 cell lines; the invasion and metastases ability of transfected BcaCD885 cell lines decreased obviously.

CONCLUSION

nm23-H1 can inhibit the metastases of BcaCD885 cell lines significantly.

Retinoic acid receptors and cancer

Retinoids have been shown to inhibit the growth of many human tumor cells. Although the exact molecular mechanism of retinoid-mediated growth suppression remains known, the importance of the retinoic acid receptors (RARs) and retinoid X receptors (RXRs) has been in established a number of tumor cell models. We wanted to determine if modulation of RAR/RXR function would alter the retinoid sensitivity of oral squamous carcinoma cells (SCCs). Growth of SCCs was significantly suppressed by treatment with either all-trans retinoic acid (RA) or the synthetic, conformationally restricted RAR-gamma-selective retinoids SR 11254 and SR 11389. In contrast, stable oral SCC clones that constitutively overexpressed the mouse dominant negative mutant, RAR-beta (R269Q), were shown to exhibit reduced RAR/RXR transcriptional transactivation function and reduced sensitivity to growth inhibition by RA, SR 11254 and SR 11389. Likewise, the RAR-gamma antagonist SR 11253 was found to block the ability of SR 11254 and SR 11389 to inhibit SCC growth. These results indicate that modulation of RAR function through the use of either an RAR-gamma-selective antagonist or a pan-RAR dominant negative mutant significantly alters the growth inhibitory response of oral SCCs to retinoids.