Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Keiji Tomita is active.

Publication


Featured researches published by Keiji Tomita.


BioMed Research International | 2015

Gamma-Glutamylcyclotransferase: A Novel Target Molecule for Cancer Diagnosis and Treatment

Susumu Kageyama; Eiki Hanada; Hiromi; Keiji Tomita; Tatsuhiro Yoshiki; Akihiro Kawauchi

Gamma-glutamylcyclotransferase (GGCT) is one of the major enzymes involved in glutathione metabolism. However, its gene locus was unknown for many years. Recently, the gene for GGCT was found to be identical to C7orf24, which is registered as a hypothetical protein. Orthologs have been found in bacteria, plants, and nematodes as well as higher organisms, and the GGCT gene is highly preserved among a wide range of species. GGCT (C7orf24) was also reported as an upregulated protein in various cancers. Although the function of GGCT in cancer cells has not been determined, the following important activities have been reported: (1) high expression in various cancer tissues and cancer cell lines, (2) low expression in normal tissues, (3) inhibition of cancer cell proliferation via anti-GGCT RNAi, (4) inhibition of cancer cell invasion and migration via anti-GGCT RNAi, (5) an epigenetic transcriptional regulation in cancer cells, and (6) an antitumor effect in cancer-bearing xenograft mice. Therefore, GGCT is promising as a diagnostic marker and a therapeutic target for various cancers. This review summarizes these interesting findings.


Reproductive Biomedicine Online | 2012

Successful delivery following ICSI with macrocephalic sperm head syndrome: a case report.

Yoshihiko Shimizu; Fuminori Kiumura; Shoji Kaku; Mika Izuno; Keiji Tomita; Dean Thumkeo; Takashi Murakami

This article reports a case of macrocephalic sperm head syndrome, which is defined as the presence of a very high percentage of spermatozoa with enlarged heads and multiple flagellae, together with detailed morphological analysis. After a couple presented with infertility, sperm analysis showed severe teratozoospermia and almost all of the spermatozoa had macrocephaly with multiple tails. The morphological analysis revealed that most of the sperm heads contained several nuclei and had a similar number of tails as that of nuclei. However, detailed analysis revealed that there were a very few spermatozoa with an almost normal morphology. After genetic counselling, intracytoplasmic sperm injection was performed using a few spermatozoa that had an almost normal morphology, resulting in pregnancy and successful delivery. Even in macrocephalic sperm head syndrome, which may be caused by meiotic division failure, pregnancy is possible if some spermatozoa with almost normal morphology can be utilized, although there may be genetic risks.


Biology of Reproduction | 2016

The Effect of d-Aspartate on Spermatogenesis in Mouse Testis

Keiji Tomita; Hiroyuki Tanaka; Susumu Kageyama; Masayuki Nagasawa; Akinori Wada; Ryosuke Murai; Kenichi Kobayashi; Eiki Hanada; Yasutoshi Agata; Akihiro Kawauchi

ABSTRACT Spermatogenesis is controlled by hormonal secretions from the hypothalamus and pituitary gland, by factors produced locally in the testis, and by direct interaction between germ cells and Sertoli cells in seminiferous tubules. Although the mammalian testis contains high levels of d-aspartate (d-Asp), and d-Asp is known to stimulate the secretion of testosterone in cultured Leydig cells, its role in testis is unclear. We describe here biochemical, immunohistochemical, and flow cytometric studies designed to elucidate developmental changes in testicular d-Asp levels and the direct effect of d-Asp on germ cells. We found that the concentration of d-Asp in mouse testis increased with growth and that fluctuations in d-Asp levels were controlled in part by its degradative enzyme, d-aspartate oxidase expressed in Sertoli cells. In vitro sperm production studies showed that mitosis in premeiotic germ cells was strongly inhibited by the addition of d-Asp to the culture medium. Moreover, immunohistochemical analysis demonstrated that d-Asp accumulated in the differentiated spermatids, indicating either transport of d-Asp to spermatids or its de novo synthesis in these cells. Such compartmentation seems to prevent premeiotic germ cells in mouse testis from being exposed to the excess amount of d-Asp. In concert, our results indicate that in mouse testis, levels of d-Asp are regulated in a spatiotemporal manner and that d-Asp functions as a modulator of spermatogenesis.


International Journal of Urology | 2015

Proteome research in urothelial carcinoma.

Susumu Kageyama; Takahiro Isono; Hideaki Iwaki; Eiki Hanada; Keiji Tomita; Tetsuya Yoshida; Tatsuhiro Yoshiki; Akihiro Kawauchi

In all creatures including humans, the molecules that function in accordance with the genetic code are mainly proteins. After completing the sequencing of the human genome, rapid progress has been made in proteome analysis. The primary structures of almost all proteins were determined by the human genome sequence. However, the whole picture of proteins cannot be elucidated because of alternative splicing and post‐translational modifications. Therefore, genomic as well as systematic and comprehensive information of proteins is required. Modern methods of proteomics have dramatically improved the quality and speed of protein analysis. Developments in both bioinformatics and mass spectrometry have contributed to the technical improvement, making it possible to identify proteins in a short time with high accuracy even from a very small sample. In the field of cancer research, many studies of useful diagnostic and prognostic biomarkers using these proteomic technologies have been reported, and target molecules for treatment have been explored. The aim of the present review was to summarize the basic technologies of proteomics and recent research in the field of urothelial cancer obtained using proteomic methods.


Clinical Nuclear Medicine | 2009

Evaluation of hydronephrosis with tubeless cutaneous ureterostomy using Tc-99m MAG3 diuretic renography.

Chul Jang Kim; Keita Takimoto; Keiji Tomita; Takashi Osafune; Nobuyuki Nishikawa; Kazuyoshi Johnin; Yusaku Okada

Purpose: To assess hydronephrosis of tubeless cutaneous ureterostomy using Tc-99m mercaptoacetyltriglycine (MAG3) diuretic renogram. Materials and Methods: Cutaneous ureterostomy with a unilateral stomal creation was performed in 15 patients (27 renal units) with a minimum follow-up period of 6 months. Stomal obstruction was evaluated with Tc-99m MAG3 diuretic renography 3 months after the surgery. The data analyses were performed with half-times to tracer clearance (T1/2) after furosemide (0.5 mg/kg) administration. Results: T1/2 means were 7.27 ± 7.11, 5.69 ± 4.63, and 8.96 ± 8.37 minutes for total, ipsilateral, and contralateral kidneys, respectively, in side relationships between ureter and stoma. There were no statistical differences among the groups. Six months after the surgery, of 26 renal units (96.3%) that had achieved a tubeless condition, and 25 renal units (92.6%) had no hydronephrosis. T1/2 was within 20 minutes in these 25 renal units, and of 25 renal units 23 (92%) revealed less than 15 minutes in T1/2, suggesting that the upper limit of T1/2 for nonobstructed systems after construction of a cutaneous ureterostomy might be 15 minutes. Mild hydronephrosis without the need for intervention was present in 1 renal unit (T1/2, 31.70 minutes). Catheterization was performed in one renal unit (T1/2, 21.04 minutes) due to acute pyelonephritis and persistence of grade 2 hydronephrosis 5 months after the surgery. Only these 2 renal units showed more than 20 minutes in T1/2, resulting in an obstructive pattern on diuretic renography. Conclusion: Tc-99m MAG3 diuretic renography with T1/2 assessment is useful to evaluate stomal stenosis in tubeless cutaneous ureterostomy.


PLOS ONE | 2018

Prediction of intravesical recurrence of non-muscle-invasive bladder cancer by evaluation of intratumoral Foxp3+ T cells in the primary transurethral resection of bladder tumor specimens

Ryosuke Murai; Yasushi Itoh; Susumu Kageyama; Misako Nakayama; Hirohito Ishigaki; Kazuo Teramoto; Mitsuhiro Narita; Tetsuya Yoshida; Keiji Tomita; Kenichi Kobayashi; Akinori Wada; Masayuki Nagasawa; Shigehisa Kubota; Kazumasa Ogasawara; Akihiro Kawauchi

Patients with a history of non-muscle-invasive bladder cancer sometimes have recurrence of tumors after transurethral resection of bladder tumor treatment. To find factors related to the recurrence of non-muscle-invasive bladder cancer, we examined tissue specimens taken at transurethral resection of bladder tumor as an initial treatment. We revealed the association between prognosis of non-muscle-invasive bladder cancer and infiltration of Foxp3+ T cells that suppress anti-tumor immunity in 115 primary non-muscle-invasive bladder cancer patients retrospectively identified and followed for at least 3 months after primary transurethral resection. In immunohistological staining, we counted the number of cells positive for CD3 and positive for CD3 and Foxp3 together and calculated the percentage of Foxp3+ T cells among the CD3+ T cells. The recurrence-free survival rate was calculated by the Kaplan-Meier method, and a Cox regression analysis of recurrence factors was performed. The median (interquartile range) percentage of Foxp3+ T cells in all cases was 17.1% (11.9, 11.4–23.3%). Compared by risk stratification, it was 11.4% (10.4, 7.8–18.2%) in the low-risk group (n = 32), 16.8% (12.6, 11.6–24.2%) in the intermediate-risk group (n = 45), and 22.0% (9.7, 16.4–26.1%) in the high-risk group (n = 38). The Kaplan-Meier survival analysis indicated that the Foxp3+ T cell high group (≥ 17.1%) had a worse RFS rate than did the low group (< 17.1%) (P = 0.006). In multivariate analysis, the percentage of Foxp3+ T cells was an independent risk factor for intravesical recurrence (hazard ratio 2.25). Thus, peritumoral Foxp3+ T cell infiltration was correlated to risk stratification and recurrence-free survival. Therefore, the percentage of Foxp3+ T cells in tumor specimens may predict a risk for intravesical recurrence.


Urology | 2017

Indocyanine Green Angiography-assisted Laparoendoscopic Single-site Varicocelectomy

Keiji Tomita; Susumu Kageyama; Eiki Hanada; Tetsuya Yoshida; Yuki Okinaka; Shigehisa Kubota; Masayuki Nagasawa; Kazuyoshi Johnin; Mitsuhiro Narita; Akihiro Kawauchi

OBJECTIVE To study the efficacy of a new laparoscopic varicocelectomy technique using indocyanine green (ICG) angiography. METHODS Laparoendoscopic single-site (LESS) varicocelectomy using ICG angiography was performed in a single institution on 11 patients with a grade 2 or 3 varicocele. Adult men (N = 9, 82%) who were apparently infertile and had a varicocele, as well as prepubertal boys (N = 2, 18%) with testicular growth retardation, underwent a LESS varicocelectomy using ICG angiography. After the separation of testicular veins, arteries, and lymphatics, ICG was injected intravenously, and arterial and venous blood flows were observed by ICG fluorescence. Spermatic veins were cauterized by bipolar forceps and cut. The spermatic artery and lymphatics were preserved. RESULTS The mean time to the arterial phase (AP) from the ICG injection was 34.9 seconds and the mean time to the venous phase was 58.3 seconds. The mean interval from the arterial phase to the venous phase was 23.3 seconds, and in all cases, this time interval facilitated the identification of arteries and veins. The rates of residual varicocele 3 and 6 months after surgery were 9.1% and 0%, respectively. Serious postoperative complications were not observed nor were adverse events induced by ICG. CONCLUSION ICG angiography appears to be safe and appears to facilitate the detection of artery and veins during LESS varicocelectomy. Continuing investigations of efficacy are required of this new and promising procedure in a larger number of patients.


The Journal of Urology | 2017

V9-05 LAPAROSCOPIC VARICOCELECTOMY USING INTRAOPERATIVE NAVIGATION: INDOCYANINE GREEN ANGIOGRAPHY AND INDIGO CARMINE LYMPHATIC DYE

Keiji Tomita; Eiki Hanada; Susumu Kageyama; Kazuyoshi Johnin; Mitsuhiro Narita; Akihiro Kawauchi

INTRODUCTION AND OBJECTIVES: Male circumcision (MC) provides a variety of medical benefits, including a 50-60% reduced risk of HIV transmission. The ShangRing is one of two WHO-prequalified MC devices and it comprises a key component of the scale-up of MC services in Africa. The No-Flip ShangRing circumcision technique represents a further simplification of this procedure. The objective of this study was to evaluate the outcomes of this technique in African adults and adolescents with regard to procedure duration, pain, adverse events, healing time, and patient satisfaction. Further, we sought to compare safety, healing rates and patient satisfaction after ring removal at 7 days versus spontaneous detachment. METHODS: We enrolled patients 10 years of age or older at two study sites in Kenya. All procedures were performed by physicians or nurses trained in the No-Flip ShangRing technique. Patients were randomized in 1:1 fashion to ring removal at 7 days versus spontaneous detachment. Outcomes were assessed weekly until 42 days or complete wound healing. RESULTS: 230 patients were enrolled in this study, age ranges 10 to 54. Over 80% of circumcisions were performed by nurses trained in the No-Flip technique. All patients (230/230) were suitable for ShangRing MC regardless of the presence of phimosis or adhesions. On subgroup analysis of patients 10-15 years of age versus >15 years, though more patients in the younger group required a dorsal slit and breaking down of adhesions prior to ring insertion, there was no difference in operative time and all circumcisions were successfully completed (Table 1). There was no difference in pain or adverse events between the age groups, and there was 97% patient satisfaction in both groups. Within the group randomized to spontaneous detachment, 72.4% of patients experienced detachment at median 14 days; 27.6% of patients requested ring removal due to pain or discomfort. There were no differences between spontaneous detachment and 7-day removal with regard to healing time, adverse events, or patient satisfaction. CONCLUSIONS: The No-Flip ShangRing procedure is simple, safe, effective, and acceptable for use in patients 10 years of age or older. Spontaneous detachment is safe and effective, and has the potential to reduce the burden of service provision in resource-poor settings.


Case Reports in Oncology | 2015

Metastatic Prostatic Ductal Adenocarcinoma Successfully Treated with Docetaxel Chemotherapy: A Case Report

Ryo Fujiwara; Susumu Kageyama; Keiji Tomita; Eiki Hanada; Teruhiko Tsuru; Tetsuya Yoshida; Mitsuhiro Narita; Takahiro Isono; Akihiro Kawauchi

A 68-year-old man presented with gross hematuria. A papillary urethral tumor adjacent to the verumontanum was found by cystourethroscopy. Serum prostate-specific antigen (PSA) was 3.246 ng/ml. A transurethral biopsy specimen was most suggestive of a primary urothelial carcinoma of the prostate, for which a radical cystoprostatectomy was performed. The final pathology was prostatic ductal adenocarcinoma with very focal acinar features (Gleason score 5 + 4 = 9, pT3bN0M0). Local recurrence and pelvic bone metastases developed 17 months later, and his PSA rose to 10.806 ng/ml. He was treated with combined androgen blockade and radiation. Two years later, the lesion showed progressive growth. Treatment followed with docetaxel (70 mg/m2 every 3 weeks) and prednisolone 5 mg twice daily. After 10 cycles of chemotherapy, all lesions disappeared and PSA decreased to <0.005 ng/ml. Three years after chemotherapy, he maintains a complete response without any additional treatments. Docetaxel chemotherapy can be an effective treatment for patients with recurrent prostatic ductal adenocarcinoma.


BMC Urology | 2018

The location of the bladder neck in postoperative cystography predicts continence convalescence after radical prostatectomy

Susumu Kageyama; Tetsuya Yoshida; Masayuki Nagasawa; Shigehisa Kubota; Keiji Tomita; Kenichi Kobayashi; Ryosuke Murai; Teruhiko Tsuru; Eiki Hanada; Kazuyoshi Johnin; Mitsuhiro Narita; Akihiro Kawauchi

Collaboration


Dive into the Keiji Tomita's collaboration.

Top Co-Authors

Avatar

Akihiro Kawauchi

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Susumu Kageyama

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Eiki Hanada

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Mitsuhiro Narita

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Tetsuya Yoshida

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Kazuyoshi Johnin

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Masayuki Nagasawa

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Kenichi Kobayashi

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Ryosuke Murai

Shiga University of Medical Science

View shared research outputs
Top Co-Authors

Avatar

Shigehisa Kubota

Shiga University of Medical Science

View shared research outputs
Researchain Logo
Decentralizing Knowledge