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Biomedical subjects

Y Shioyama

Publications and source records attributed to Y Shioyama.

At least 19 recordsLinked to original sources
PubMed2006

Usefulness of mini-tracheostomy and torque controlled insertion of applicator in fractionated endobronchial brachytherapy.

Endobronchial brachytherapy was developed as effective treatment of endobronchial cancer and fractionated schedule is applied to decrease late toxicity. However, repeated bronchofiberscopy is onerous to the patient and restricts the treatment schedule itself. We applied mini-tracheostomy for a ready access route, and a torque controlled technique for easy insertion of the endobronchial applicator. Eight patients with tracheobronchial cancer invasion were treated with endobronchial brachytherapy of 18-30 Gy/3-5 fractions/1.5-2.5 weeks (median 24 Gy/4 fractions/2 weeks) at reference points of 5 mm from the bronchial surface. The averaged individual irradiation and single session times were 4 min and 24 min, respectively. There were no procedure-related complications. These technical improvements may facilitate flexible fractionated dose prescriptions.

Aged↗
PubMed2004

Gluteal muscular and sciatic nerve metastases in advanced urinary bladder carcinoma: case report.

We present a case of gluteal muscular and sciatic nerve metastases from urinary bladder carcinoma. T2-weighted magnetic resonance images demonstrated diffuse swelling and an increase in the signal of the right gluteus maximus muscle without destruction of the original arrangement of muscular fibers. Further, remarkable thickening of the right sciatic nerve showing a relatively hypointense signal was detected. Postcontrast T1-weighted images showed strong enhancement of these structures. Fine-needle aspiration biopsy with ultrasonographic guidance confirmed metastatic carcinoma cells in the right gluteal muscle and the sciatic nerve. These radiologic findings may represent a rare pattern of metastasis from urinary bladder carcinoma.

Adenocarcinoma↗
PubMed2001

Self-expandable metallic stents for patients with recurrent esophageal carcinoma after failure of primary chemoradiotherapy.

BACKGROUND: Recent advances in chemoradiotherapy for esophageal carcinoma have resulted in improved survival rates. However, there are few options for recurrent dysphagia due to refractory carcinoma after failure of primary chemoradiotherapy. The aim of this study was to evaluate the safety and efficacy of self-expandable metallic stent placement for patients with recurrent esophageal carcinoma where definitive chemoradiotherapy has failed. METHODS: Thirteen consecutive patients with recurrent squamous cell carcinoma of the esophagus, in whom self-expandable metallic stents were placed after failure of primary chemoradiotherapy, were studied retrospectively. All patients had esophageal obstruction or malignant fistula. RESULTS: The oral alimentation status of nine of 13 patients (69%) improved after successful placement of the stent. Following placement of the stent, fever (>38 degrees C) and severe chest pain occurred in 85% (11/13) of the patients. In all patients examined, C-reactive protein was elevated within 1 week of the operation. Esophageal perforation occurred in three patients. Stent-related mediastinitis and pneumonia developed in six (46%) and three (23%) patients, respectively. Seven of the 13 patients (54%) died of stent-related pulmonary complications. CONCLUSION: Although the placement of a self-expandable metallic stent for patients with recurrent esophageal carcinoma after failure of chemoradiotherapy improved their oral alimentation status, we found that this treatment increases the risk of life-threatening pulmonary complications.

Adult↗
PubMed2001

[Visualization of abdominal arteries by super-high-flow venous injection using multidetector helical CT].

The purpose in this study was to compare the ratio of visualization of upper abdominal arteries using MDHCT between the super-high-flow injection method (Group A) and the conventional injection method (Group B). The subjects ects were 200 patients who were randomly divided into Group A (100 patients) and Group B (100 patients). In Group A, visualization of the large arteries, including the CE, SMA, HA and LGA, was possible at a rate exceeding 96%, and that of the small arteries, including the DPA, SPDA, RGA and Cyst A, was more than 79%. Visualization of upper abdominal arteries was markedly improved by the super high flow injection technique.

Abdomen↗
PubMed2000

Different mutation frequencies and spectra among organs by N-methyl-N-nitrosourea in rpsL (strA) transgenic mice.

The frequencies and spectra of N-methyl-N-nitrosourea (MNU)-induced in vivo somatic mutations were determined in rpsL (strA) transgenic mice. The wild-type rpsL gene, which exhibits a streptomycin-sensitive (Sm(S)) phenotype, was used as the rescue marker gene. Studies of mutation spectra among different organs and tissues were simplified using this system because of the short coding sequence (375 bp) of the rpsL gene. MNU administration to transgenic mice significantly elevated the mutation frequencies in various adult organs. Two distinctive patterns of mutation spectrum were observed, depending on the organs tested. Mutations derived from labile organs (spleen and thymus) were predominantly G:C to A:T transitions, as expected for MNU mutagenesis. Stable organs like the liver and brain, however, carried many fewer G:C to A:T transitions but significantly more single base deletions, of which the spectrum was very similar to that of background mutations in the rpsL transgenic mice. This spectrum difference among more and less proliferating organs was confirmed by the predominant occurrence of G:C to A:T transitions in fetal liver cells exposed to transplacental MNU treatment. In addition, most (approximately 90%) of the G:C to A:T transitions induced by MNU were detected in the first nucleotide of some 5'-G-(C or G)-3' sequences, many of which corresponded to the middle guanine residue of 5'-purine-G-(C or G)-3' sequences. It is thus suggested that at particular sites, the neighboring bases in both the 5' side and 3' side seem to influence either the susceptibility to DNA damage or the ability to repair MNU-induced lesions.

Age Factors↗
PubMed2000

[Long-term results of TIPS].

The long-term results of transjugular intrahepatic portosystemic shunt(TIPS) were analyzed in 48 patients between February 1992 and December 1998, for treatment of esophageal varices and ascites caused by portal hypertension. The procedure was successful in 42 patients. Portal vein pressure was reduced from 29 mmHg +/- 7.9 to 19 mmHg +/- 7.3 immediately after TIPS and to 17 mmHg +/- 6.5 one year later. Varices were controlled in 82% (23/28) of patients after one year and in 78% (7/9) of patients after five years. Ascites disappeared or decreased in 79% (11/14) after one year. Primary shunt patency was 12%, with a secondary patency rate of 79% after five years. The overall incidence of new or worsened encephalopathy was 31% (13/42). Long-term follow-up showed one-, three-, and five-year survival rates of 82%, 68%, and 59%, respectively. TIPS is an effective means of lowering portal hypertension, and it controls varices and ascites with little risk of hepatic encephalopathy.

Adult↗
PubMed2000

[Therapeutic effect of TAE in patients with hepatocellular carcinoma using color Doppler imaging with intravenous ultrasound contrast agent].

We evaluated the therapeutic effect of TAE in 9 nodules with hepatocellular carcinoma (HCC) using color Doppler flow imaging with an intravenous ultrasound contrast agent. The intratumoral color signal enhancement that was detected in 7 nodules resulted in complete disappearance after TAE. The other 2 nodules without color signal enhancement showed well-differentiated HCC with fatty degeneration on histological study. The intratumoral enhancement noted in dynamic MRI in 7 of the 9 nodules resulted in complete disappearance after TAE. Color Doppler flow imaging with an intravenous contrast agent is a promising method for assessing the therapeutic effect of TAE.

Aged↗
PubMed1999

Pancreatoduodenectomy for locally advanced or recurrent colon cancer: report of two cases.

A 66-year-old man, who had ascending colon cancer which invaded the duodenum, pancreas, and superior mesenteric vein, underwent a curative resection including an extended right hemicolectomy, pylorus-preserving pancreatoduodenectomy, and a partial resection of the superior mesenteric vein. The pathological examination revealed adenocarcinoma of the colon, which directly invaded the duodenum and pancreas, thus causing duodenocolic fistula. Tumor infiltration to the superior mesenteric vein was not histologically proven. Two out of 40 lymph nodes were also involved. The patient is still alive and disease-free 37 months after the operation. A 72-year-old man, with a history of surgery two previous times for ascending colon cancer and its recurrence, underwent a third operation including a resection of the former ileocolic anastomosis en bloc by means of a pylorus-preserving pancreatoduodenectomy with a curative intent. The pathological examination revealed adenocarcinoma of the colon, which directly invaded the duodenum and pancreas. Seven out of 31 lymph nodes were also involved. The patient died of recurrence 24 months after the third operation. These two cases demonstrated the usefulness of a resection of the colon en bloc by means of a pancreatoduodenectomy in patients with either locally advanced colon cancer or locally advanced recurrent colon cancer.

Adenocarcinoma↗
PubMed1999

Inhibition of benzo[a]pyrene-induced mutagenesis by (-)-epigallocatechin gallate in the lung of rpsL transgenic mice.

Epigallocatechin gallate (EGCG) is a major water-soluble component of green tea. The antimutagenic activity of EGCG against benzo[a]pyrene (B[a]P)-induced mutations was assessed by using transgenic mice carrying the rpsL gene as a monitor of mutations. Seven-week-old male mice were given drinking water containing EGCG for 3 weeks. On day 7, mice were treated with a single i.p. injection of B[a]P (500 mg/kg body wt). Two weeks after the injection, the mutations in the rpsL gene were analyzed. B[a]P treatment resulted in an approximately 4-fold increase of mutation frequency at the rpsL gene in the lung. An approximately 60% reduction in the B[a]P-induced mutations in the lung was observed when mice were given EGCG at concentrations >0.005%. B[a]P-induced mutations mainly occurred at G:C basepairs in the several specific nucleotide sequences of the rpsL gene. These were AGG, CGG, CGT, TGG, TGC and GGT: all of them contained a guanine residue. Mutations seen similarly in the human Ki-ras codon 12 or p53 codons 157, 248, and 273 of lung tumor were also found in the rpsL gene, and the mutations were suppressed by the EGCG treatment. In conclusion, the antimutagenic effects of EGCG for B[a]P-induced mutagenesis in vivo suggest that drinking green tea may reduce the tumor-initiating potency of B[a]P in the lung.

Animals↗
PubMed1999

Non-Hodgkin lymphoma and coexisting primary cancers: a retrospective clinical analysis of 10 patients.

The simultaneous occurrence of non-Hodgkin lymphoma (NHL) and primary cancers is rare, and the treatment strategy for both malignancies is unclear. The authors analyzed the clinical records of 10 patients with NHL and coexisting primary cancers. All patients initially had symptoms of NHL, and all carcinomas were found at the initial workup of NHL by chance. The most common primary sites of coexisting cancers were the stomach (six patients) and the colon (two). Histologically, the majority of NHLs were intermediate grade, and all lesions were B-cell type. All primary cancers were adenocarcinoma. Initially, NHL was treated with radiotherapy or chemotherapy. Six primary cancers were resected surgically or endoscopically after the remission of NHL. The remaining four patients received no treatment for primary cancers because of advanced stages or early relapse of NHL. Three patients died of NHL, one died of cancer, and six were still alive, five without evidence of disease and one with disease. The authors conclude that early detection of a coexisting cancer and appropriate treatment after the remission of NHL may increase the possibility of a cure.

Adenocarcinoma↗
PubMed1998

The high susceptibility of heterozygous p53(+/-) mice to malformation after foetal irradiation is related to sub-competent apoptosis.

PURPOSE: To investigate the relationship between the incidence of radiation-induced malformations and the extent of p53-dependent apoptosis. MATERIALS AND METHODS: Wild-type p53(+ / +) and heterozygous p53(+ / -) mice were exposed to X-rays at the mid-gestational period. The incidence of anomalies and prenatal deaths, the extent of apoptosis, and the levels of p53 protein were assessed. RESULTS: After X-irradiation with 2 Gy, the incidence of malformation (corrected for control levels) was 0 and 30%, respectively, for p53(+ / +) and p53(+ / -). After irradiation of p53(+ / +) foetuses with 3 Gy, the frequency (F) of apoptotic cells rapidly peaked at 80% at 4 h and fell close to the control level at 48 h. The relationship between F 4h after irradiation and dose (D) (1-3Gy) is accurately expressed by a single-hit equation, F= 1 -exp ( -(a + bD)¿, where the radiation-induced apoptosis rate, b, is 0.47 for the wild type and 0.22 for the heterozygous mice. The X-irradiated foetuses showed no increase in the levels of p53 protein. CONCLUSION: The higher susceptibility of irradiated p53(+ / -) foetuses to malformation is related to a twofold lower rate of apoptosis; competent removal by apoptosis of damaged cells from irradiated tissues is impaired dramatically if one of two wild-type p53 alleles is lost. The frequency of apoptotic cells in the wild type reached a maximum 4h after foetal irradiation with no measurable increase in the level of p53 protein, indicating that radiation-induced p53-mediated foetal apoptosis depends on non-transcriptional events.

Alleles↗
PubMed1997

[Comparison of Gore-tex covered Ultraflex stent and bare Ultraflex stent: preliminary clinical results].

We clinically compared the covered Ultraflex stent and the bare Ultraflex stent for malignant esophageal strictures. Materials were 6 cases with esophageal carcinomas. We placed the Gore-tex covered stents (A group) in 4 cases including 2 cases of esophagorespiratory fistulae, and the bare stents (B group) in 2 cases. The stents were well-expanded in all cases. After stenting, dysphagia was improved in all cases. Fistulae were obstructed by the cover in 2 cases in A group. Mean survival term was 123 days in A group and 45 days in B group. Complications were fistulation of bare portion of the covered stent in one case in A group, and tumor bleeding in one case in B group. Considering of the risk of fistula or tumor bleeding, the cover is necessary to increase the safety and efficacy of the esophageal stent.

Aged↗
PubMed1997

[Evaluation of hepatic encephalopathy and portal hemodynamics by Doppler ultrasonography after a transjugular intrahepatic portosystemic shunt].

TIPS (transjugular intrahepatic portosystemic shunt) is an efficacious treatment for esophagogastric varices, ascites and hypertensive gastrointestinal vasculopathy associated with portal hypertension. The main complication after the procedure is hepatic encephalopathy. We tried to elucidate the correlation between hepatic encephalopathy and changes in portal hemodynamics after TIPS, based on observation by Doppler ultrasonography. We carried out Doppler ultrasonography in 28 cases of TIPS to assess hepatopetal and hepatofugal blood flow in the right and left portal branches. Hepatic encephalopathy occurred after TIPS in 9 cases out of 28 (32%), and new onset of disease was observed in 6 of 9. Doppler ultrasonography revealed hepatofugal blood flow in both right and left portal branches in 6 cases, 5 of which showed encephalopathy. Hepatopetal blood flow of the right and left portal branches was observed in 17 of 28 cases after TIPS. Hepatic encephalopathy occurred in only 2 of 17 cases. The changes in portal vein hemodynamics after TIPS were investigated by color Doppler ultrasonography, which were considered to be very useful for prediction of hepatic encephalopathy and indication of medical treatment to prevent the occurrence of this disease.

Adult↗
PubMed1996

A novel positive detection system of in vivo mutations in rpsL (strA) transgenic mice.

To positively detect the in vivo mutations accumulated in different mouse organs, we have developed a transgenic mouse system. This transgenic mouse carried an Escherichia coli (E. coli) plasmid pML4 as a shuttle vector that consisted of a replication origin (ori), the kanamycin-resistant gene (KanR) and the rpsL+ gene (strAS) derived from E. coli. These E. coli elements were expected to be inert in the transgenic mouse system; thus, neutral mutations would be accumulated on the shuttle plasmid in the transgenic mice. The shuttle plasmid vector was recovered from the mouse genomic DNA and introduced into kanamycin-sensitive (KmS) and streptomycin-resistant (SmR) E. coli cells by using electroporation. The original pML4 shuttle plasmid transformed the host E. coli to KmR and SmS, since both the KanR and rpsL genes exhibited dominant traits of KmR and SmS, respectively. On the other hand, when the retrieved pML4 shuttle plasmid carried a mutated rpsL gene, it could be positively detected as both KmR and SmR. Based on this principle, we were able to positively detect the in vivo mutations accumulated in the rpsL transgene of the shuttle vector pML4 integrated into the mouse genome. The total number of rescued shuttle plasmids were counted on the plates containing Km alone, while only mutants were detected on the plates containing both Km and Sm. We have so far established 22 independent transgenic mouse lines that carried up to approx. 750 copies of the shuttle plasmid pML4 in a haploid genome. By using high-copy-number transgenic mouse lines which carried 350 copies or more of the shuttle vector, we also developed a simple and proficient method for retrieving the shuttle plasmid from various tissues of the transgenic mice. The background mutant frequency was approx. 5 x 10(-5). In order to validate the applicability of the positive-detection transgenic system for the induced mutagenicity assay, methylnitrosourea (MNU) was administered to the transgenic mice, and an increase in the number of mutant frequencies was seen in all tested organs including spleen, liver and brain. The rpsL transgenic mouse system was therefore considered to provide a quick-and-easy risk assessment test for in vivo tissue-specific mutagenicity, using positive detection by streptomycin.

Animals↗
PubMed1996

[Spiral volumetric CT venography of the lower extremities: preliminary report].

Twelve cases, including varicose veins (7), deep venous thrombosis (3), A-V malformation (1) and skin ulcer (1), were examined by three-dimensional CT venography (3D CTV), and comparison was made with conventional ascending venography. In the "double phase method," the first phase scan (40 seconds) of the femoral region was performed in order to rule out deep venous thrombosis, and the second phase scan (30 seconds) of the lower leg was performed to visualize varicose veins. Veins of the thigh and popliteal space were relatively well visualized. It is thought that 3D-CTV is particularly useful for spatially evaluating deep venous thrombosis and varicose veins.

Arteriovenous Malformations↗
PubMed1996

[Gore-tex covering of ultraflex stent and its usefulness for malignant esophageal stenosis: preliminary clinical results].

Malignant esophageal stenoses develop esophagorespiratory fistulae or perforations so frequently that esophageal stents must be required. We devised a covered stent with a thin Gore-Tex sheet and a nitinol stent system, Ultraflex, without increasing the size of the introducer assembly. Nine patients with malignant esophageal stenoses, including seven patients with perforation or fistulation, were carefully treated with the covered stent. All stent deployments were successfully carried out under fluoroscopic guidance. The average time required for full self-expansion was two weeks. The average grade of dysphagia improved from 3.7 to 1.2. Clinical symptoms due to esophagorespiratory fistulae were improved in three of four patients. No clinical or technical complications, such as migration, were observed, but a fistula developed at the bare site of the stent. This covering method for the flexible stent was simple and safe, and was considered to be useful in the treatment of malignant esophageal stenosis.

Adenocarcinoma↗