Eichner classification based on panoramic X-ray images using deep learning: A pilot study.

BACKGROUND: Research using panoramic X-ray images using deep learning has been progressing in recent years. There is a need to propose methods that can classify and predict from image information. OBJECTIVE: In this study, Eichner classification was performed on image processing based on panoramic X-ray images. The Eichner classification was based on the remaining teeth, with the aim of making partial dentures. This classification was based on the condition that the occlusal position was supported by the remaining teeth in the upper and lower jaws. METHODS: Classification models were constructed using two convolutional neural network methods: the sequential and VGG19 models. The accuracy was compared with the accuracy of Eichner classification using the sequential and VGG19 models. RESULTS: Both accuracies were greater than 81%, and they had sufficient functions for the Eichner classification. CONCLUSION: We were able to build a highly accurate prediction model using deep learning scratch sequential model and VGG19. This predictive model will become part of the basic considerations for future AI research in dentistry.

Recurrence of renal cell carcinoma after simultaneous radical nephrectomy and cadaver renal transplant.

Introduction: Generally, renal transplantation is contraindicated in cancer patients, and a certain follow-up period is required. We report a case of late recurrence of renal cell carcinoma in a patient who underwent simultaneous radical nephrectomy and cadaver renal transplantation due to renal cell carcinoma observed during renal transplantation after 12 years. Case presentation: Incidental renal cell carcinoma was found in a 48-year-old man during kidney transplantation who subsequently underwent simultaneous cadaver kidney transplantation and radical nephrectomy. Twelve years after transplantation, he developed an anterior mediastinal tumor, a lung tumor which was resected and a right adrenal gland mass which was resected along with the right kidney. Currently, he is being treated with tyrosine kinase inhibitors owing to the metastasis in the left adrenal gland. Conclusion: In patients with metastatic carcinoma undergoing renal transplant, the indications for surgical procedures and choice of immunosuppressants should be carefully considered.

Prevalence of reflux esophagitis in obese Japanese undergoing bariatric surgery.

BACKGROUND: Currently, the data on the relationship between obesity and gastroesophageal reflux disease (GERD) in Asian populations are scarce. METHODS: The aim of this study is to investigate the prevalence of reflux esophagitis (RE) among obese Japanese patients in each body mass index (BMI) range group. In addition, we aim to investigate the risk factors for RE in obese Japanese patients. The present retrospective cohort study included 674 obese Japanese patients who underwent bariatric surgery between January 2003 and April 2016. The patients were stratified into five groups based on BMI range. RESULTS: The mean BMI was 42.7 ± 9.24 kg/m2. The prevalence of RE among each of the groups was as follows: Group 1 (BMI 30-34.9) = 20.7%; Group 2 (BMI 35-39.9) = 24.0%; Group 3 (BMI 40-44.9) = 25.2%; Group 4 (BMI 45-49.9) = 26.7%; and Group 5 (BMI ≥50) = 24.8%. Overall, the prevalence of RE was 24.2% in our study. Furthermore, no significant difference in BMI was noted between the RE and non-RE groups (43.4 ± 9.3 kg/m2 and 42.5 ± 10.2 kg/m2, respectively; p = 0.24). According to the multivariate logistic regression model, gender, Helicobacter pylori infection status, GERD-related symptoms, and hiatal hernia were significantly correlated with RE. CONCLUSION: Our study shows that the prevalence of RE in severely obese Japanese patients was significantly higher than the average prevalence of RE in Japan. However, the prevalence of RE did not increase with BMI in our cohort.

[CLINICAL STUDY OF THE PROSTATE CANCERS WITH A SERUM PROSTATE SPECIFIC ANTIGEN LEVEL OF MORE THAN 100 ng/ml AT THE FIRST DIAGNOSIS].

In patients with prostate cancer high serum prostate specific antigen (PSA) at diagnosis was generally regarded as a strong impression of advanced disease with distant metastasis and poor prognosis. (Objective) We reported a retrospective study of prognostic factor and Overall survival (OS) in patients with prostate specific antigen (PSA) level of greater than 100 ng/ml (PSA≥100 ng/ml). (Subjects and methods) Between January 2002 and December 2015, 60 patients were diagnosed prostate cancer with PSA≥100 ng/ml and performed hormonal monotherapy at Kanazawa Medical University hospital. We evaluated initial PSA level, Gleason score, Gleason Grading Group, clinical stage, site of metastasis, PSA nadir level, Time to PSA nadir (TTN), serum Hemoglobin (Hb) level, serum C-Reactive Protein (CRP) level, serum Lactate Dehydrogenase (LDH) level, serum Alkaline Phosphatase (ALP) level, clinical passage and survival time. (Results) The median age of the patients was 73 years old (54-90) and the initial PSA levels ranged from 100 ng/ml to 15,823 ng/ml (median 390).Prognostic factors of overall survival were site of metastasis, Gleason score, Gleason Grading Group, PSA nadir level, TTN, serum CRP level, serum LDH level and serum ALP level at the diagnosis. In multivariate analysis serum LDH level remained an independent predictor of OS.

Early gastric cancer successfully treated by endoscopic submucosal resection 1 year after laparoscopic sleeve gastrectomy with duodenal-jejunal bypass.

This case involved a 64-year-old female patient with a BMI of 35.3 kg/m2 and poorly controlled type 2 diabetes mellitus. Preoperative upper gastrointestinal endoscopy revealed chronic, atrophic gastritis. Helicobacter pylori antibody was negative. The patient underwent laparoscopic sleeve gastrectomy with duodenal-jejunal bypass as a metabolic surgery to treat obesity and type 2 diabetes mellitus. At 1 year postoperatively, routine endoscopy detected a flat elevated lesion at the distal gastric sleeve, near the posterior wall of the antrum; biopsy revealed adenocarcinoma. Endoscopic submucosal resection was performed without complication. This case shows the advantage of laparoscopic sleeve gastrectomy with duodenal-jejunal bypass in screening the excluded stomach as compared to laparoscopic Roux-en-Y gastric bypass. Therefore, laparoscopic sleeve gastrectomy with duodenal-jejunal bypass can be a viable alternative to laparoscopic Roux-en-Y gastric bypass for regions where gastric cancer is endemic.

[Clinical Study on the Efficacy and Continuous Docetaxel Based Chemotherapy Treatment for Castration-Resistant Prostate Cancer].

We report a retrospective study on the efficacy, adverse events and the factors for continuous docetaxel (DOC) therapy for patients with castration-resistant prostate cancer (CRPC). Between April 2007 and April 2015, 37 CRPC patients were treated with DOC therapy at Kanazawa Medical University Hospital. DOC was administered every 3 weeks at 70 mg/m2. Prostatic specific antigen (PSA) level, adverse events, cycles of DOC therapy, survival time and clinical passage were examined. Fifteen patients showed a decrease in PSA level of 50% or more, 9 patients showed less than 50% decrease in PSA level and 13 patients showed no decrease in PSA level. Adverse effect of grade 3 consisted of neutropenia in 29.7% and leukocytopenia in 10.8%. The median number of treatment cycles was 11.7 courses. The patients were divided into two groups ; the first group comprised of 26 patients who received short-term DOC therapy (≤10 cycles) and the second group comprised of 11 patients who received long-term DOC therapy (≥11 cycles). The 1-year survival rate was 59 and 100% for the short-term and long-term groups, respectively. Long-term treatment was related to pretreatment PSA nadir, time to progression of CRPC and serum lactate dehydrogenase level.

L-Arginine L-Glutamate Enhances Gastric Motor Function in Rats and Dogs and Improves Delayed Gastric Emptying in Dogs.

Amino acids are not only constituents of proteins, but also have multiple physiologic functions. Recent findings have revealed that ingested amino acids either activate luminal receptors or are metabolized, causing physiologic reactions in the gastrointestinal (GI) tract. We examined the effect of oral L-arginine L-glutamate (ArgGlu), a pharmaceutical amino acid salt used i.v. for the treatment of hyperammonemia, on gastric motor function in rats and dogs. Gastric emptying was determined using phenol red and 13C-breath test methods, whereas gastric relaxation was determined using the barostat method. ArgGlu (10-30 mg/kg, p.o.) dose-dependently promoted gastric emptying in rats. This effect was dependent on vagus nerve activation and comparable to that of the prokinetic mosapride. Intragastric ArgGlu (3-30 mg/kg intragastrically) also dose-dependently enhanced adaptive relaxation of rat stomachs, which was negated not by vagotomy of gastric branches, but by pretreatment with N omega-nitro-L-arginine methyl ester (20 mg/kg i.v.), a nitric oxide synthase inhibitor. Its relaxing effect on the stomach was also confirmed in dogs and was equally as efficacious as treatment with sumatriptan (1-3 mg/kg s.c.). ArgGlu (30 mg/kg p.o.) significantly reduced the half gastric emptying time in clonidine-induced delayed gastric emptying of solids in dogs, and its effect was comparable to that of cisapride (3 mg/kg p.o.). This study demonstrated that the pharmaceutical ingredient ArgGlu, currently used i.v., enhanced gastric motor function when administered orally, suggesting that it could be a new oral medicine indicated for treatment of upper GI hypofunction or dysfunction like functional dyspepsia.

THE EFFECT OF RADIATION THERAPY FOR BONE METASTASIS IN URINARY ORGAN CANCER.

(Objective) Bone metastasis symptoms are complications that greatly reduce the quality of life (QOL) of cancer patients. We report a retrospective study on the efficacy of radiation therapy for patients with bone metastasis in urinary organ cancer. (Subjects and methods) Subjects are comprised of 17 patients; total irradiated areas consist of 25 sites. There are 5 patients diagnosed with renal cell carcinoma, 1 patient with bladder cancer and 11 patients with prostatic cancer. All of them have undergone radiation therapy for bone metastasis in urinary organ cancer between April 2007 and March 2014 in the Department of Urology, Kanazawa Medical University. The mean age of the patients was 66.7 years old. We looked at irradiated areas, exposure dose and changes of symptom in all patients. (Results) Irradiated areas are thoracolumbar vertebrae (14 sites), cranial base (2 sites), pubic bone (1 site), ilium bone (2 sites), sacral bone (1 site), rib bone (1 site) and hip joint (1 site). The mean exposure dose of one area is 37.5 Gy (13.5-60). 19 irradiated sites which were previously reported to have sharp pain have gained improvement at 16 sites. These 16 sites have comparatively lesser pain or no pain. 8 cases in acknowledgment of walk difficulty, it was with 7 cases walking alone possibility again. (Conclusion) This study showed that radiation therapy have significant improvement in terms of symptoms and QOL for the patients with bone metastasis in urinary organ cancer.

Classification of Physiological 18F-fluorodeoxyglucose Uptake in the Large Intestine: a Preliminary Study.

Varying degrees of physiological uptake of 18F-fluorodeoxyglucose (FDG) are often noted in the large intestine and can be problematic when interpreting positron emission tomography (PET) images. In relation to colorectal tumor detection with FDG PET, we tentatively classified physiological FDG uptake in the large intestine according to its patterns and intensity. Subjects were 144 asymptomatic individuals (109 men, 35 women; mean age 57.5 ± 10.1 years) in our cancer screening program who underwent total colonoscopy within 24 days of FDG PET study and showed no evidence of colonic lesions on colonoscopy. Distinct FDG uptake on FDG PET images was classified into four types: focal, defined as distinctly nodular and visible on at least 4 axial; localized, 2 to 8 cm with SUVmean ≥ 4; diffuse, > 8 cm with SUVmean ≥ 4; and mixed, of more than one type. SUVmeans were examined by placing multiple circular regions of interest of 1 cm in diameter on the axial images. We found 21 distinct FDG uptakes matching our criteria in 20 of 144 subjects (13.9%): focal (n = 4), localized (n = 1), diffuse (n = 14), and mixed (n = 1; focal and diffuse). With regard to colorectal tumor detection, 6 subjects (4.2%) with focal or localized type of uptake were considered at risk of false-positive tumor identification, and 15 subjects (10.4%) with diffuse type of uptake were considered at risk of their tumors being missed at the site of FDG uptake. To confirm the feasibility of our criteria, this classification should be tested with a larger number of subjects.

Quantitative assessments of arousal by analyzing microsaccade rates and pupil fluctuations prior to slow eye movements.

It is well known that a decline of arousal level causes of poor performance of movements or judgments. Our previous study indicates that microsaccade (MS) rates and pupil fluctuations change before slow eye movements (SEMs) (Honda et al. 2013). However, SEM detection of this study was obscure and insufficient. In this study, we propose a new SEM detection method and analyze MS rates and pupil fluctuations while subjects maintain their gaze on a target. We modified Shin et al.'s method, which is optimized for EOG (electrooculography) signals, to extract the period of sustaining SEMs using a general eye tracker. After SEM detection, we analyzed MS rates and pupil fluctuations prior to the initiation of SEMs. As a result, we were able to detect SEMs more precisely than in our previous study. Moreover, the results of eye movements and pupil fluctuations analyses show that gradual rise of MS rate and longitudinal miosis are observed prior to the initiation of SEMs, which is consistent with our previous study. These findings suggest that monitoring eye movements and pupil fluctuations may evaluate the arousal level more precisely. Further, we found that these tendencies become more significant when they are restricted to the initial SEMs.

Quantitative evaluation of arousal level based on the analyses of microsaccade rates and pupil fluctuations.

In this study, we proposed an objective estimation of decline of arousal level by analyzing microsaccade rate and pupil fluctuation while subjects were continuously gazing a fixation target. Previous studies show that the slow eye movements (SEMs) could be a candidate for an indicator of decline of arousal. However, it is not sufficient to evaluate transition of arousal states since SEMs appear just prior to sleep onset. To establish more objective assessment of arousal, we examined the effects of the transition of arousal on microsaccade rate and pupil fluctuation. The subjects were instructed to indicate by mouse clicks when they were aware of having slept. We have analyzed the eye movement and pupil fluctuation data in advance of the occurrence of SEMs which were detected just before the mouse clicks. In the results, longitudinal pupil diameter shrinking and gradual rise of microsaccade rate were observed prior to SEMs. These results suggest that the arousal level could be evaluated by monitoring eye movements and pupil fluctuations.

[Combination chemotherapy of docetaxel and UFT against hormone refractory prostate cancer].

Docetaxel-based chemotherapy has been shown to be effective and well tolerated by Japanese patients with metastatic hormone-refractory prostate cancer (HRPC). This study was undertaken to assess the feasibility of docetaxel in combination with UFT (a combination of tegafur and uracil) in Japanese patients with HRPC. Ten patients aged 60-86 years with HRPC, who were pre-treated with hormonal therapy and expected to have more than 3 month survival and without major organ dysfunction, were included in this study. Treatment consisted of docetaxel 70 mg/m2 every 3 weeks plus UFT 260 mg/m2 /day. The primary end point was prostate-specific antigen (PSA) response, and the secondary end points included progression-free survival and toxicity. Nine patients were evaluable for efficacy and toxicity. The PSA response rate was 50% (1 CR and 4 PR). The most common non-hematological adverse events (of any grade) possibly related to treatment were neutropenia and anorexia. Grade 3/4 neutropenia and anorexia occurred in 50 and 20% of patients, respectively. The combination of docetaxel and UFT was feasible and active in Japanese patients with HRPC, with a manageable adverse-event profile similar to that observed in lung cancer chemotherapy.

[Evolution of strategy to measure urinary supersaturation].

Urinary stones have an estimated lifetime morbidity of 15.1% in males and 6.1% in females ; in other words, one out of seven males and one out of fifteen females are affected with this disease at least once in their life. Previously, we reported a simple and easy method using microplates to measure the metastable limit (ML), which indicate the upper limit of supersaturation dissolution. In this study, we examined the usability of this microplate method. We confirmed that ML is correlated with the urinary calcium concentration in healthy subjects, single stone formers (SF), and recurrent stone formers (RSF). There was no significant difference between healthy subjects and RSF in urinary magnesium concentration, and ML was found to be correlated with urinary the concentration of oxalate and citrate acid in healthy subjects only. These results suggest that ML is a simple and easy way to measure the urinary calcium level and that ML could be a useful test item in outpatient settings as a convenient indicator for preventing recurrence of urinary stones in the future.

[Marginal - donor and recipient].

A significant gap exists between organ supply and demand in the world. Marginal donors have been accepted as organ donors in recent years. On the other hand, aging recipients and recipients with complications have increased. This symposium was organized to discuss marginal donors and high risk recipients. We discussed fundamental researches such as prevention of renal ischemia reperfusion injury by erythropoitin and hepatocyte growth factor-macrophage stimulating protein (HGF-MSP) chimera, and the acquired tolerance induction using the CD28 superagonist antibody. We believe that this discussion will help increase the number of cadaveric kidney transplantations and improve the treatment outcome.

[Renal protective effects of erythropoietin on ischemic reperfusion injury].

We reexamined the conditions of tissue disorders resulting from temporary ischemia of the organs as well as changes in tissue function and the effects on the preservation of renal function over time by using rat models in order to clinically utilize erythropoietin, which has inhibitory effects on ischemia-reperfusion disorders. In 8- to 9-week-old Wister male rats, after the right kidney had been resected under general anesthesia, the left renal artery was clamped to inhibit the blood flow for 45 minutes. At 30 minutes before inhibiting the blood flow and after releasing the inhibited blood flow, 100 U/kg of recombinant human erythropoietin (rhEPO) was administered via the inferior vena cava and the abdominal cavity, and then the tissues and blood samples were extracted at 6 hours and 24 hours after the release. The renal tissue specimens were evaluated for apoptosis and renal function using hematoxylin eosin staining and TUNEL staining. Changes in the emergence of active oxygen were investigated by using blood samples. The degree of renal dysfunction was evaluated by measuring neutrophil gelatinase-associated lipocalin (NGAL) in the spot urine samples. The changes in the serum creatinine level, showed that the renal function was preserved with a significant difference in the rhEPO administration group. The liver deviation enzymes clearly decreased in the rhEPO administration group. Active oxygen did not change before and after the ischemia-reperfusion nor was it changed by rhEPO administration. Apoptosis was inhibited by rhEPO administration. No direct effects of rhEPO administration on the emergence of active oxygen were observed. The administration of rhEPO, was suggested to help preserve the renal function in marginal donors with a longer agonal stageby effectively.

A case of second renal transplantation with acute antibody-mediated rejection complicated with BK virus nephropathy.

We reported a 40-year-old female case of second renal transplantation with antibody-mediated rejection (AMR) complicated by BK virus nephropathy. She started hemodialysis (HD) at the age of 17 because of IgA nephropathy. At the age of 18, she underwent living-donor kidney transplantation from her father, but two and a half years after transplantation, she developed chronic rejection. This time, she received cadaveric renal transplantation under the negative cross-match (AHG-LCT), and HLA-AB 1 mismatch and -DR 1 mismatch. Immunosuppressive therapy was initiated using the following four immunosuppressants: methylprednisolone, mycophenolate mofetil, cyclosporine, and basiliximab. However, renal graft showed delayed function, the biopsy showed glomerulitis (g2), endarteritis (v1), and cellular infiltration (ptc3) consisting mainly of mononuclear cells in the peritubular capillary with diffusely positive C4d and anti-SV 40 large T-antigen-positive renal tubular epithelial cells on post-operative day 19. The donor-specific antibody for HLA-B46 was proven by the LAB screen method. We performed plasma exchange three times and administered immunoglobulin (15 g in total). Then, methylprednisolone pulse therapy was added, and the serum creatinine (SCr) levels gradually decreased. On post-operative day 44, the patient was removed from HD and was discharged with SCr level of 3.3 mg/dL.

Renal protective effects of erythropoietin on ischemic reperfusion injury.

While the problem of organ shortage has not yet been solved, the number of patients who need to be treated with dialysis due to end-stage renal disease (ESRD) is increasing each year. With the aim of eliminating dialytic therapy as much as possible, the opportunities for organ donation from expansive criteria donor (ECD) or marginal donors due to cardiac death have been increasing. With the purpose of extracting organs in a state in which the function is preserved as much as possible, we reexamined the conditions of tissue disorders resulting from temporary ischemia of the organs as well as changes in tissue function and the effects on the preservation of renal function over time by using rat models in order to clinically utilize erythropoietin, which has inhibitory effects on ischemia-reperfusion disorder, as has been conventionally reported. With 8- to 9-week-old Wister male rats, after the right kidney had been resected under general anesthesia, the left renal artery was clamped to inhibit the blood flow for 45 min. At 30 min before inhibiting the blood flow and after releasing the inhibited blood flow, 100 U/kg of recombinant human erythropoietin (rhEPO) was administered via the inferior vena cava and the abdominal cavity, and then the tissues and blood samples were extracted at 6 and 24 h after the release. The renal tissue specimens were evaluated using H&E staining and TUNEL staining in order to observe differences in the expression of apoptosis as well as the renal function and changes in the emergence of active oxygen were investigated by using samples that had been obtained from drawn blood. Moreover, we examined the degree of renal dysfunction by means of neutrophil gelatinase-associated lipocalin (NGAL) in the spot urine samples. The changes in renal function, which were observed according to the serum creatinine level, showed that the renal function was preserved with a significant difference in the rhEPO administration group. The liver deviation enzymes, which had also shown increases in the serum as well as the occurrence of renal dysfunction, showed clear decreases in the serum, even though changes with a significant difference were not observed in the rhEPO administration group. The active oxygen did not show changes before and after ischemia-reperfusion nor changes due to the rhEPO administration. When examining the status of apoptosis in the tissues, apoptosis was shown to be inhibited due to the rhEPO administration. It is believed that the main preservation effects of rhEPO are the elimination of cytopathy/cell death, as derived from the resulting ischemic condition that extends to the target organ before ischemia occurs. In this examination, no direct effects of rhEPO administration on the emergence of active oxygen were observed. It is therefore suggested that there is a possibility of preserving the renal function in marginal donors with a longer agonal stage by effectively using rhEPO.

Significance of dynamic magnetic resonance sialography in prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia.

PURPOSE: To evaluate the clinical significance of dynamic magnetic resonance (MR) sialographic images in prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia. MATERIALS AND METHODS: Morphologic findings and functional parameters were evaluated by use of dynamic MR sialography before saline solution irrigation of the parotid gland for the treatment of xerostomia in 17 patients. In addition, the MR sialographic data before the saline solution irrigation treatment in patients with improvement of salivary secretion and the sensation of dry mouth after irrigation treatment were compared with data in patients without improvement. RESULTS: The maximum changing ratio in the group of patients with improvement after treatment was significantly higher (P = .042) than that in the group of patients without improvement. In addition, high correlations were found between the changing ratio and improvement on the visual analog scale for dry mouth sensation after treatment (Pearson r = 0.63, P = .001) and improvement of salivary flow rate (Pearson r = 0.77, P = .001). Moreover, in 12 patients with improvement of salivary flow rate after the saline solution irrigation treatment, the maximum changing ratio before the saline solution irrigation treatment was over 1.2. However, no significant differences in other parameters, including the detectable ductal area, were found between the group of patients with improvement after treatment and the group without improvement. CONCLUSIONS: Our study suggests that dynamic MR sialography might be useful for the prognostic evaluation of saline solution irrigation of the parotid gland for the treatment of xerostomia.

Inhibitions of urinary oxidative stress and renal calcium level by an extract of Quercus salicina Blume/Quercus stenophylla Makino in a rat calcium oxalate urolithiasis model.

OBJECTIVES: To clarify the mechanism of Urocalun, an extract of Quercus salicina Blume/Quercus stenophylla Makino (QS), in the treatment of urolithiasis. METHODS: Rat calcium oxalate urolithiasis was induced by oral administration of ethylene glycol and the vitamin D3 analog alfa-calcidol for 14 days. QS extract was repeatedly given to rats. After the last administration, biochemistries in urine and plasma, renal calcium, and urinary malondialdehyde (an oxidative stress marker) were measured. RESULTS: Ethylene glycol and alfa-calcidol treatment increased urinary malondialdehyde and renal calcium levels. This increase was significantly suppressed by the administration of QS extract, suggesting that the inhibition of renal calcium accumulation by QS extract is due to its antioxidative activity. CONCLUSIONS: These findings suggest that the antioxidative activity of QS extract plays a role in the prevention of stone formation and recurrence in urolithiasis.

Effects of oxalate exposure on Madin-Darby canine kidney cells in culture: renal prothrombin fragment-1 mRNA expression.

It has been suggested that renal tubular cell damage induced by oxalic acid, one of the components of urinary calculi, may be involved in a variety of ways in the development of urolithiasis. During our study on a calculus related protein, renal prothrombin fragment-1 (RPTF-1), we noted that this is an inflammation related substance that mediates an acute inflammatory reaction, one of the original roles of prothrombin. RPTF-1 is a part of prothrombin that is a coagulation factor known to be expressed in the renal tubule. We examined whether oxalic acid may cause cytotoxic effects on tubular epithelial cells and whether such chemical stimulation may promote the translation of RPTF-1 mRNA into RPTF-1 proteins. We used Madin-Darby canine kidney (MDCK) cells derived from the distal tubule of a dog kidney. In this study, the effects of oxalic acid in culture solution at different concentrations on cytotoxicity were assessed using a MTT assay. The location of active oxygen species was identified using dichlorofluorescein diacetate. After the prothrombin sequence of RPTF-1 was confirmed in MDCK cells, RPTF-1 mRNA expression was determined by RT-PCR. The gene sequence of the same promoter area was ligated, and a luciferase sequence was inserted downstream of the vector. The target sequence was transfected into MDCK cells and the relation between oxalic acid and prothrombin promoter was examined. In addition, the variable expression of RPTF-1 mRNA was quantitatively compared depending on oxalic acid concentrations using real-time PCR. When cytotoxicity was investigated, cells were not damaged but, by contrast, were stimulated and activated under oxalic acid below a certain concentration. The relation between cytotoxicity on the cultured MDCK cell membrane and active oxygen species was confirmed. Luminescence in MDCK cells containing the luciferase gene was detected by the addition of oxalic acid, which activated the prothrombin promoter. A part of the prothrombin gene sequence in the MDCK cells was detected and an increase in the expression of RPTF-1 mRNA in MDCK cells by the addition of oxalic acid was confirmed using real-time PCR. Increased expression of prothrombin by adding oxalic acid has already been demonstrated in previous studies. In this study, however, RPTF-1 mRNA was promoted by oxalic acid and a direct association between oxalic acid and RPTF-1 is indicated. This finding shows that increased oxalic acid in urine induces the expression of RPTF-1 in tubular epithelial cells and thereby causes the generation of active oxygen species.