Comparison of Tooth Whitening Efficacy between Gel and Strip with Light Activator / 치위생과학회지

The study aimed to compare the whitening efficacy of a strip and gel containing 2.9% hydrogen peroxide, using a tooth whitening light activator. The whitening effect was compared through in vitro and in vivo studies. In the in vitro study, we used stained hydroxyapatite (HAP) specimens as artificial teeth. HAP specimens were made using HAP powder and polyvinyl alcohol solution, and stained by modified Stookey's method. A whitening gel and whitening strip were applied to the respective specimens for 20 minutes, with a light activator. The color changes were measured using a colorimeter. In the in vivo study, one group (test 1) used the gel with a light activator and the other group (test 2) used a strip with the same activator for 15 minutes a day, for four consecutive days. An organoleptic evaluation using a Vita shade guide and instrumental evaluation using a Shade eye-NCC (Shofu Co., Japan) were performed. The color change values (ΔE*) in the in vitro study revealed the strip with the light activator to be more effective than the gel with the same activator (p<0.001). In the in vivo study, even though there was no significant difference between the groups with respect to the ΔE*, using either the Shade eye-NCC or the Vita shade guide, the change in yellowness (Δb*) was statistically significant (p=0.024). In conclusion, test 2 group that used 2.9% hydrogen peroxide strip with a light activator, showed a tendency towards increased whitening than test 1 group that used the gel with the same activator; however further studies are needed to validate the above finding.

Evaluation of In-Vitro Efficacy of Active Ingredients in Dentifrice Used for Different Treatment Times / 치위생과학회지

The purpose of this study was to evaluate the in-vitro efficacy of the active ingredients of dentifrice following treatment time. The whitening effect was evaluated by a change in lightness value relative to the contact time of hydrogen peroxide, by using artificially stained hydroxyapatite discs. The anti-calculus effect was assessed based on the amount of calcium eluted from the human dental calculus by sodium pyrophosphate. Remineralization was evaluated by the Vickers hardness test following the application of sodium fluoride to bovine enamel. In order to view dentinal tubules occlusion, the formation of insoluble calcium salts by bovine dentin specimens was observed using scanning electron microscopy. Change in lightness value (ΔL) was 5.50±1.51 after 1 min of treatment, 5.73±0.43 after 3 min, 8.64±0.24 after 10 min, 18.93±0.76 after 30 min, and 27.35±0.54 after 60 min. The amount of calcium eluted from the human dental calculus was 4.23±0.14 ppm after 1 min of treatment, 4.51±0.04 ppm after 3 min, 12.12±0.16 ppm after 10 min, 17.85±0.81 ppm after 30 min, and 25.15±0.32 ppm after 60 min. The Vickers hardness change value (ΔVHN) was 1.96±1.44 after 1 min, 1.52±1.06 after 3 min, 9.06±0.15 after 10 min, 10.83±5.13 after 30 min, and 12.55±2.09 after 60 min. Partial dentinal tubules occlusion was observed at 10 min and complete occlusion was evident at 60 min. In summary, the use of patch type dentifrices for 10, 30, or 60 min were 1.57 to 8.26 times more effective than using the paste type dentifrices for 1 to 3 min. Based on these findings, it is reasonable to expect that the use of patch type dentifrices for 10 min would lead to remineralization, anti-calculus and dentinal tubules occlusion effects, and that use for 30 min would result in a whitening effect.

Effects of a whitening strip combined with a desensitizing primer on tooth color / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the efficacy of a 2.9% hydrogen peroxide (HP) whitening strip with a desensitizing agent as a primer. METHODS: This study was approved by the Institutional Review Board of Kyungpook National University Hospital. A total of 144 subjects (mean age: 21.7 years) were recruited after they provided informed consent for participation in the study. All participants used the whitening strip and primer for 1.5 h a day for 14 days. ShadeEye-NCC and Vita classical shade guide were used to determine the color changes, with respect to baseline, after 1, 3, 5, 7, and 14 days. A self-administered questionnaire was used to collect data on satisfaction after bleaching and irritating symptoms during the 14 days. All collected data were analyzed with repeated measures ANOVA and one-way ANOVA using SPSS 20.0 for windows. RESULTS: Brightness (ΔL*) was significantly higher in groups 2 and 3 than in the control group after 3 days of the experiment. Chroma (Δb*) started to decrease in groups 2 and 3, compared to control, after 1 day. Perceived symptoms of irritation were significantly lower in groups using the strip combined with the desensitizing primer than in the control group. Satisfaction after bleaching was higher in the experimental groups than in control. CONCLUSIONS: The HP whitening strip with a desensitizing agent as a primer is clinically effective in bleaching human enamel after 3 days of use. It also reduces the prevalence of gingival irritation.

Protective role of oligonol from oxidative stress-induced inflammation in C6 glial cell

BACKGROUND/OBJECTIVES: Natural products or active components with a protective effect against oxidative stress have attracted significant attention for prevention and treatment of degenerative disease. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from Litchi chinensis Sonn. We investigated the protective effect and its related mechanism of oligonol against oxidative stress. MATERIALS/METHODS: Oxidative stress in C6 glial cells was induced by hydrogen peroxide (H2O2) and the protective effects of oligonol on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) synthesis, and mRNA expression related to oxidative stress were determined. RESULTS: Treatment with oligonol inhibited NO and ROS formation under cellular oxidative stress in C6 glial cells. In addition, it recovered cell viability in a dose dependent-manner. Treatment with oligonol also resulted in down-regulated mRNA expression related to oxidative stress, nuclear factor kappa-B (NF-kappaB) p65, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), compared with the control group treated with H2O2. In particular, expression of NF-kappaB p65, COX-2, and iNOS was effectively reduced to the normal level by treatment with 10 microg/mL and 25 microg/mL of oligonol. CONCLUSIONS: These results indicate that oligonol has protective activity against oxidative stress-induced inflammation. Oligonol might be a promising agent for treatment of degenerative diseases through inhibition of ROS formation and NF-kappaB pathway gene expression.

Nomogram for Prediction of Prostate Cancer with Serum Prostate Specific Antigen Less than 10 ng/mL

Although prostate-specific antigen (PSA) is a very useful screening tool, prostate biopsy is still necessary to confirm prostate cancer (PCA). However, it is reported that PSA is associated with a high false-positive rate and prostate biopsy also has various procedure-related complications. Therefore, the authors have devised a nomogram, which can be used to estimate the risk of PCA, using available clinical data for men with a serum PSA less than 10 ng/mL. Prostate biopsies were obtained from 2,139 patients from January 1998 to March 2011. Of them, 1,171 patients with a serum PSA less than 10 ng/mL were only included in this study. Patient age, PSA, free PSA, prostate volume, PSA density and percent free PSA ratio were analyzed. Among 1,171 patients, 255 patients (21.8%) were diagnosed as PCA. Multivariate analyses showed that patient age, prostate volume, PSA and percent free PSA had statistically significant relationships with PCA (P < 0.05) and were used as nomogram predictor variables. The area under the (ROC) curve for all factors in a model predicting PCA was 0.759 (95% CI, 0.716-0.803).

Laparoscopic Ureteroneocystostomy: Modification of Current Techniques

PURPOSE: To review the feasibility of laparoscopic ureteroneocystostomy with extracorporeal eversion of the ureteral end in various distal ureteral lesions. MATERIALS AND METHODS: We conducted a retrospective review of 5 laparoscopic procedures of ureteroneocystostomy with extracorporeal eversion of the ureteral end. Of these, 4 patients (range, 45 to 54 years) had distal ureter stricture or obstruction after gynecological surgeries for endometriosis or a large uterine myoma. One patient (male, 67 years) had low-grade distal ureter cancer. The laparoscopic procedure was combined with cystoscopic insertion of a ureteral stent and extracorporeal eversion of the ureter through the 10-mm port on the affected side. RESULTS: The laparoscopic ureteral reimplantations with and without a psoas hitch in patients with distal ureteral lesions was successful in all patients. The mean operation time was 137 minutes (range, 104 to 228 minutes). Two patients underwent additional psoas hitch. In all patients, short-term success was confirmed by voiding cystourethrography and intravenous pyelography conducted 3 months after the operation. The mean follow-up of the entire group was 12 months (range, 3 to 30 months). We noted no major or minor complications over the follow-up period. CONCLUSIONS: The technique of laparoscopic ureteroneocystostomy for benign or malignant ureteral strictures continues to evolve. Surgeons should be versatile with various options and technical nuances when dealing with these cases. Simple modifications of laparoscopic ureteroneocystostomy with extracorporeal eversion of the ureteral end, nonreflux extravesical anastomosis, and simultaneous cystoscopy will be crucial to the ease of performance and a successful outcome.

Primary Undifferentiated Penile Sarcoma in Adolescence

We report a case of primary penile undifferentiated sarcoma. A 16-year-old adolescent man visited Pusan National University Hospital complaining of a painless mass on his penis that was increasing in size. Magnetic resonance images revealed a 5x5-cm mass and pathological examinations revealed small round cell sarcomas with neuroendocrine differentiation. The tumor, which had metastatic pulmonary nodules, was treated by tumorectomy and systemic chemotherapy. Thirty-four months after the initial diagnosis, the patient was still alive without evidence of local recurrence or metastatic disease. This is our second case of an undifferentiated penile sarcoma.

Torsion of an Indirect Hernia Sac Causing Acute Scrotal Swelling in a Child

Torsion of a hernia sac is an extremely rare condition that presents as acute scrotum in children. We report a case of a 6-year-old boy who presented with an acute scrotum and was found during surgical exploration to have torsion of an indirect hernia sac associated with hydrocele. Upon scrotal exploration, deterioration of the scrotum due to inflammatory changes was found. A necrotic cyst was recognized within a communicating hydrocele of the scrotum and was twisted at an angle of about 360degrees. All urologists should be aware of this special condition in the differential diagnosis of acute scrotum.

Malignant Inflammatory Myofibroblastic Tumor of the Bladder with Rapid Progression

A 71-year-old man was referred for painless hematuria and a bladder tumor. Cystoscopy and computed tomography revealed a 3-cm oval nodular mass on the left lateral side of the bladder. The patient underwent a complete transurethral resection of the lesion and histology showed a proliferation of atypical spindle cells with inflammation consistent with a myofibroblastic tumor. After 4 and 7 months, follow-up cystoscopy demonstrated nodular mass lesions and transurethral resection of bladder tumor was done, which showed chronic cystitis and a recurred myofibroblastic tumor, respectively. Five months later, multiple lymph node, bone, and soft tissue metastases were found by positron emission tomography. The patient was treated first with palliative chemotherapy, including doxorubicin and cisplatin. After that, radiologic studies showed disease progression but the patient refused further treatment and died 6 months later.

Vesico-Appendiceal Fistula Misdiagnosed as Meckel's Diverticulum: A Laparoscopic Approach

A 26-year-old man complained of a vague low abdominal discomfort for the previous 2 months. Radiologic evaluations demonstrated that there was tubular structure connected with the right side wall of the bladder, suggesting Meckel's diverticulum with fistula formation to the bladder as well as a mass-like bladder wall thickening. With an impression of Meckel's diverticulum with fistula with the bladder, laparoscopic surgery was performed to confirm a diagnosis and to manage the Meckel's diverticulum with fistula with the bladder. The distal tip of the appendix was firmly attached to the right side of the bladder. The final diagnosis was corrected by laparoscopy followed by laparoscopic appendectomy and fistula repair. Vesico-appendiceal fistula is an uncommon type of vesico-enteral fistula and a rare complication of unrecognized appendicitis. Additionally, this report showed the significant value of laparoscopy as a diagnostic and therapeutic tool to this entity.

Postoperative renal function in patients is unaltered after robotic-assisted radical prostatectomy / 대한마취과학회지

BACKGROUND: Pneumoperitoneum with an intra-abdominal pressure (IAP) of 14 mmHg is known to decrease renal function. Robotic-assisted radical prostatectomy (RARP) requires an IAP of more than 15 mmHg for operation. Therefore, we retrospectively investigated whether patients who underwent RARP experienced renal insufficiency during the postoperative period (at postoperative days 7 and 30). METHODS: One hundred patients who underwent RARP were enrolled in this study. Preoperative serum blood urea nitrogen (BUN) and serum creatinine (Cr) levels were measured. Creatinine clearance (CrCl) was calculated using the Cockcroft and Gault formula. CrCl was calculated at 1 day before surgery (baseline), 2 hr postoperatively, and at 1, 3, 7, and 30 days postoperatively (POD 1, POD 3, POP 7, and POD 30). Patients were assigned to abnormal CrCl (n = 52) or normal CrCl groups (n = 48) on the basis of these measurements. RESULTS: Significant inter-group differences in BUN, Cr, and CrCl were observed at all postoperative time points. BUN and Cr decreased significantly at postoperative 2 hr and POD 1, 3, and 7 versus baseline in both groups, whereas CrCl increased significantly at postoperative 2 hr and POD 1, 3, and 7 versus baseline in both groups. However, BUN, Cr, and CrCl were similar at POD 30 and preoperatively in the two groups. CONCLUSIONS: RAPR, which requires an IAP of 15-20 mmHg for more than 4 hr, does not induce renal dysfunction during the postoperative period, and even in those patients with an abnormal CrCl.

Feasibility of ultrasound-guided posterior approach for interscalene catheter placement during arthroscopic shoulder surgery / 대한마취과학회지

BACKGROUND: Continuous interscalene block has been known to improve postoperative analgesia after arthroscopic shoulder surgery. This was a prospective study investigating the ultrasound-guided posterior approach for placement of an interscalene catheter, clinical efficacy and complications after placement of the catheter. METHODS: Forty-two patients undergoing elective arthroscopic shoulder surgery were included in this study and an interscalene catheter was inserted under the guidance of ultrasound with posterior approach. With the inplane approach, the 17 G Tuohy needle was advanced until the tip was placed between the C5 and C6 nerve roots. After a bolus injection of 20 ml of 0.2% ropivacaine, a catheter was threaded and secured. A continuous infusion of ropivacaine 0.2% 4 ml/hr with patient-controlled 5 ml boluses every hour was used over 2 days. Difficulties in placement of the catheter, clinical efficacy of analgesia and complications were recorded. All patients were monitored for 48 hours and examined by the surgeon for complications within 2 weeks of hospital discharge. RESULTS: Easy placement of the catheter was achieved in 100% of the patients and the success rate of catheter placement during the 48 hr period was 92.9%. Postoperative analgesia was effective in 88.1% of the patients in the post anesthetic care unit. The major complications included nausea (7.1%), vomiting (4.8%), dyspnea (4.8%) and unintended vascular punctures (2.4%). Other complications such as neurologic deficits and local infection around the puncture site did not occur. CONCLUSIONS: The ultrasound-guided interscalene block with a posterior approach is associated with a success high rate in placement of the interscalene catheter and a low rate of complications. However, the small sample size limits us to draw definite conclusions. Therefore, a well-designed randomized controlled trial is required to confirm our preliminary study.

Clinical Characteristics of Papillary Thyroid Microcarcinoma (PTMC) / 대한내분비외과학회지

PURPOSE: PTMC is defined as a papillary thyroid cancer smaller than 10 mm in its greatest diameter. It is the most common form of differentiated thyroid cancer and its prognosis is known to be very favorable. The aim of this study is to identify its biologic behavior and to formulate a reasonable therapeutic strategy for the treatment of PTMC. METHODS: 379 patients with papillary thyroid cancer were analyzed. Each patient was diagnosed preoperatively or postoperatively and treated between Jan. 2000 and Dec. 2007. Among these patients, 143 had been identified as having PTMC (37.7%) with a mean tumor size of 0.72 cm in diameter. RESULTS: There were no significant differences of the clinical characteristics such as gender, age, the operative methods, or multicentricity between the PTMC group and the non-PTMC group, except for LN metastases. Also, there were fewer symptoms of palpable neck mass and preoperative findings such as capsular invasion and microcalcification in the PTMC group. We performed unilateral lobectomy with or without central compartment neck node dissection for the early stage diseases, but for the later stages of disease we performed near-total or total thyroidectomy with routine central compartment neck node dissection. And for the patients with lateral node enlargement, we performed ipsilateral modified radical neck dissection (MRND). CONCLUSION: This study shows that PTMC is quite similar to conventional papillary thyroid cancer in its biological behavior, and we conclude that total thyroidectomy with central compartment neck node dissection is the proper therapeutic strategy to treat PTMC. However, further study is necessary for identifying the low-risk and high-risk patients with PTMC.

Risk Factors that Influence the Early Access Patency of an Arteriovenous Fistula in Hemodialysis Patients

PURPOSE: It is very important to obtain vascular access that resists repeated punctures and maintains an adequate blood flow for performing hemodialysis in patients with end stage renal disease. This study was designed to identify the risk factors that may influence the early patency rate of arteriovenous fistulas (AVFs). METHOD: We analyzed 304 cases of AVFs in 299 patients who underwent hemodialysis access surgery in our hospital from January 2000 to March 2007. The rate of early access failure and the risk factors of early access patency were evaluated retrospectively. RESULT: The rate of early access failure of an AVF was 14.5%. The early access failure group showed a higher incidence in women and in the patients with a previous history of ipsilateral central venous catheterization. Further examination by multivariate analysis demonstrated that a history of ipsilateral central venous catheterization was an independent risk factor for early access failure of AVFs. CONCLUSION: A history of ipsilateral central venous catheterization was an independent risk factor for early access failure of AVFs in this study.

Diagnosis and Treatment of Malocclusions using the Invisalign System / 대한치과교정학회지

Recent developments in software technology have made it possible to create a virtual three-dimensional model of the dental arches from digitally scanned casts of a patient's dentition. This modelmay then be manipulated with software to produce stages of tooth movement from the initial malocclusion to the final desired occlusion. A sterolithograghic model is made for each stage of tooth movement which is the basis for construction of a series of clear and thin overlay appliances. These appliances are worn full time by the patient to move the teeth according to the programmed stages of movement. Malocclusions involving mild to moderate crowding and space closure have been proven to be successfully treated with this appliance. Experience with this appliance has demonstrated excellent patient compliance with less discomfort, improved esthetics and oral hygiene control, when compared with fixed orthodontic appliances. Orthodontic treatment with this appliance is a potentially useful alternative approach to fixed appliances for treatment of a variety of malocclusions in patients with fully erupted permanent teeth.

The Change of Muscle Strength, Muscle Endurance, Flexibility and Activities of Daily Living of the Kidney Transplant Recipients / 성인간호학회지

The purpose of this study was to explore the change of muscle strength, muscle endurance, flexibility and activities of daily living to develop a rehabilitational program. The subjects were selected randomly among the patients who underwent kidney transplantations at one major transplantation hospital in Seoul, Korea. This study was carried out between November 23, 1999 and February 15, 2000. The subjects in this study consisted of 16 patients who had kidney transplantations between 1 month and 12 months ago prior to this study. They were all on steroids and did not take any physical exercise regularly. The muscle strength, muscle endurance, flexibility and activities of daily living were evaluated at 1st week and after 12 weeks. The data were analyzed with numbers, percentiles, mean, standard deviation and t-test. The results were as follows: 1. After 12 weeks, the grip strength was significantly decreased than 1st week (p=.0002). 2. After 12 weeks, the back lift strength was significantly decreased than 1st week (p=.0002). 3. After 12 weeks, the muscle endurance was increased than 1st week, but it was not significant(p=.5487). After 12 weeks, the flexibility was significantly decreased than 1st week (p=.0002). 5. After 12 weeks, the activities of daily living was significantly decreased than 1st week (p=.0006). Like the above result, the kidney transplant receipients' muscle strength, flexibility and activities of daily living were reduced. In order to solve this problem, the writer has found that program development to prevent the defects should be extremely required. Since now on the number of patients should expand. After the kidney transplantation, the periods of 4, 8, 12 and 16 weeks are extended. The writer proposes to examine the different phase of change in each periods.

The Effects of the Self Efficacy Promotion and Exercise Training Program on Anxiety, Depression and Quality of Life of Kidney Transplant Recipients / 성인간호학회지

The purpose of this study is to develop and evaluate the Self Efficacy Promotion and Exercise Training Program to decrease anxiety and depression and to increase the quality of life for kidney transplant recipients. The subjects were selected randomly among the patients who underwent renal transplant at three major transplantation hospitals in Seoul, Korea. The observed subjects in this study consisted of 56 patients who had renal transplantations between one to twelve months prior to this study. The patients did not take any regular physical exercise. This study was carried out between November, 1999 and March, 2000. The study groups were divided into 3 groups; exercise training group (n=16), self efficacy group (n=18) and control group (n=22). The exercise training group received self efficacy promotion and exercise training program for 12 weeks. The self efficacy group received self efficacy promotion education, but no exercise training was given. The control group was not offered any education. The anxiety, depression and quality of life were evaluated 3 times, before the experiment, after 8 weeks and after 12 weeks. The data were analyzed with mean, standard deviation, Chi-square test, ANOVA and Scheff test. The results were as follows: 1. After the experiment, anxiety and depression scores of the exercise training group and self efficacy group were more significantly decreased than those of the control group (p=.05). 2. After the experiment, the quality of life score of the exercise training group and self efficacy group were more significantly increased than those of the control group (p=.05). This study showed that the Self Efficacy and Exercise Training Programs were effective. Therefore, it is expected that the Self Efficacy Promotion and Exercise Training Program could be widely applied as an effective independent nursing intervention to decrease anxiety and depression and to increase quality of life for kidney transplant recipients.

The Effects of the Self Efficacy Promotion and Exercise Program on the weight, body fat rate, exercise time and cardiopulmonary function of kidney transplant recipients / 성인간호학회지

The purpose of this study is to develop and evaluate the Self Efficacy Promotion and Exercise Program to prevent of obesity and cardiovascular diseases for the kidney transplant recipients. The subjects were selected randomly among the patients who underwent kidney transplantations at one major transplantation hospital in Seoul, Korea. This study ws carried out between November 23, 1999 and February 15, 2000. The subjects in this study consisted of 16 patients who had kidney transplantations between 1 month and 12 months ago prior to this study. They were all on steroids therapy and did not take any physical exercise regularly. The subjects received the self efficacy promotion and exercise program for 12 weeks which contained self efficacy promotion education and exercise program. The weight, body fat rate, exercise time and cardiopulmonary function were evaluated before the experiment and after the experiment. The results were as follows: 1. After the experiment, the weight was significantly decreased than that of before the experiment(p=.0001). 2. After the experiment, the body fat rate was significantly decreased than that of before the experiment(p=.0010). 3. After the experiment, the exercise time was significantly increased than that of before the experiment(p=.0002). 4. After the experiment, the absolute VO2 was significantly increased than that of before the experiment(p=.0008). 5. After the experiment, the relative VO2 was significantly increased than that of before the experiment(p=.0002). This study showed that the self efficacy promotion and exercise program was effective. So it would be expected that this self efficacy promotion and exercise program could be applied as an effective independent nursing intervention widely in prevention of obesity and cardiovascular diseases for kidney transplant recipients.

Experience of the Elective Neck Dissection in Clinical N0 Neck / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The status of cervical lymph node is a great influence to the prognosis of patient with head and neck cancer. There has been a great controversies on the treatment of clinical N0 neck. The purpose of this study is to analyze the outcomes of the elective neck dissection in clinical N0 neck of various sites of primary lesion. MATERIALS AND METHODS: The authors analyzed the outcomes of elective neck dissection by retrospective study with review of records of 38 head and neck cancer patients (56 sites) who had clinically N0 neck. RESULTS: The overall rate of occult neck metastasis was 31.6%. Occult neck metastasis rates according to primary sites were 37.5% (supraglottic larynx), 25.0% (glottis), 25.0% (hypopharynx) and 20. 0% (tongue) and according to T stage were 50,0% (T1), 13.3% (T2), 57.1% (T3) and 0% (T4). Four cases had nodal recurrence (1 out of 4 had occult neck metastasis) after elective neck dissections and there were no significant postoperative complications. CONCLUSION: Due to relatively high overall occult neck metastasis rate, and no significant postoperative complications, the elective neck dissection should be considered against potential possibility of occult neck metastasis in the primary sites and extent of head and neck cancers.

Correlation of the Expression of nm23-H1/NDP Kinase A and CD44v8-10 with Head and Neck Cancer Metastasis / 체질인류학회지

The expressions of nm23-H1/NDP kinase and CD44 genes which are associated with tumor proliferation and metastasis, in 10 cases of head and neck cancer were studied by immunohistochemistry using monoclonal antibody H1-203 and CD44v8-10. And the relationship between the expressions of two genes and cancer metastasis was studied. Eight cases out of 10 head and neck cancers were squamous cell carcinomas. Normal skin epidermis and squamous cell carcinoma of the skin were used as control. The expression of nm23-H1/NDP kinase A was decreased generally in head and neck cancer comparing with normal epidermis, and more decreased in metastatic head and neck cancer. CD44v8-10 was shown strong expression in non-metastatic head and neck cancer but weak or no expression in metastatic head and neck cancer. With differentiation of tumor tissue, the expression of CD44v8-10 gene decreased. These results suggest that nm23-H1/NDP kinase and CD44 genes play a role as inhibitor to metastasis in head and neck cancer.