Search PubMed⌕ Search

Biomedical subjects

M Tawada

Publications and source records attributed to M Tawada.

5 recordsLinked to original sources
PubMed2004

Beam-beam limit in e+e- circular colliders.

Beam-beam effects limit the luminosity of circular colliders. Once the bunch population exceeds a threshold, the luminosity increases at a slower rate. This phenomenon is called the beam-beam limit. Onset of the beam-beam limit has been analyzed with various simulation methods based on the weak-strong and strong-strong models. We have observed that an incoherent phenomenon is mainly concerned in the beam-beam limit. The simulation have shown that equilibrium distributions of the two colliding beams are distorted from Gaussians when the luminosity is limited. The beam-beam limit is estimated to be xi approximately 0.1 for a B factory with damping time of several thousand turns.

Journal Article↗
PubMed2001

[A case of renal pelvic tumor with heterotopic bone formation].

The patient was a 74-year-old man who was referred to our hospital with a complaint of left flank pain. Laboratory data were almost within normal limits and urine cytology was positive. X-ray examination revealed a calcification in the left kidney and abdominal CT scan confirmed the presence of a heterogenous renal pelvic mass which contained a calcification. Based on these examinations, a diagnosis of a renal pelvic cancer with heterotopic bone formation was made. Subsequently, left nephroureterectomy was performed. Grossly, the renal pelvis of the resected kidney was filled with a mass which had a white cut surface and bone-like tendency. Histopathologically, a poorly differentiated transitional cell carcinoma with massive bone formation was found. Fifty five cases of heterotopic bone formation in the kidney have been reported in Japan. Among the cases, 4 cases were complicated with renal pelvic tumor and our case was the second case of heterotopic bone formation complicated with a transitional cell carcinoma of the renal pelvis in Japan.

Aged↗
PubMed2000

[Two cases of nephrogenic adenoma in the bladder diverticulum].

We report two cases of a nephrogenic adenoma in the bladder diverticulum. The first patient was an 81-year-old man with gross hematuria. Cystoscopy revealed bladder diverticulum and a papillary tumor within. Bladder diverticulectomy was performed and the histopathological diagnosis was a nephrogenic adenoma. The second patient was a 50-year-old man with gross hematuria and dysuria. Transabdominal ultrasound revealed bladder diverticulum. Transurethral coagulation of the bladder diverticulum was performed. Then three papillary tumors were detected, and were resected transurethrally. The histopathological diagnosis was a nephrogenic adenoma. These are the first and second cases of a nephrogenic adenoma in the bladder diverticulum reported in Japan.

Adenoma↗
PubMed2000

[Intra-arterial infusion chemotherapy for liver metastases of testicular tumors: report of two cases].

Two cases of testicular tumors with lymph node involvement and multiple lung and liver metastases were treated successfully with intra-arterial infusion chemotherapy. Case 1: A 30-year-old man presented with right scrotal swelling and an abdominal mass. He had a large retroperitoneal mass and multiple lung and liver metastases on computed tomographic (CT) scan and chest X-ray. Right inguinal orchiectomy was performed. Histopathological diagnosis revealed embryonal cell carcinoma and choriocarcinoma. Cisplatin, vinblastine, VP-16 and pepleomycin combination chemotherapy (PVeBV) was started and repeated for 2 courses. The retroperitoneal mass and lung tumors decreased in size, but liver tumors enlarged. Systemic and intrahepatic arterial infusion combined with chemotherapy was administered, and intra-arterial chemotherapy (cisplatin, VP-16) was added. The patient also received systemic chemotherapy (carboplatin, VP-16, ifosfamide). After chemotherapy, retroperitoneal lymph node dissection was performed. Microscopic examination revealed no viable cancer cells. On CT scan, no retroperitoneal, liver, or lung tumor was detected. Case 2: A 43-year-old man presented with right scrotal swelling and an abdominal mass. CT scan revealed a large retroperitoneal mass as well as lung and multiple liver metastases. Right inguinal orchiectomy was performed. Histopathological diagnosis revealed seminoma. Cisplatin, vinblastine, VP-16 and pepleomycin combination chemotherapy (PVeBV) was administered, but the liver tumors ware enlarged on CT scan. Intrahepatic arterial infusion chemotherapy (cisplatin, VP-16) was started and repeated for 4 courses. On CT scan, the lung metastasis seemed to have disappeared, and the retroperitoneal mass and liver metastases were decreased in size.

Adult↗