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Kouichi Isobe

Publications and source records attributed to Kouichi Isobe.

9 recordsLinked to original sources
PubMed2005

Toxicities and effects of involved-field irradiation with concurrent cisplatin for unresectable carcinoma of the pancreas.

PURPOSE: To evaluate local effects and acute toxicities of involved field irradiation with concurrent cisplatin (CDDP) for unresectable pancreatic carcinoma. MATERIALS AND METHODS: Thirty-three patients with unresectable pancreatic carcinoma were treated with chemoradiotherapy. Sixteen were Stage IVA; 17 were Stage IVB. The total prescribed dose of radiotherapy was 50 Gy/25 fractions or 50.4 Gy/28 fractions, using a three-dimensionally determined involved-field that included only the primary tumor and clinically enlarged lymph nodes. Twelve patients received a daily i.v. infusion of CDDP; 21 patients received a combination of CDDP and 5-fluorouracil either i.v. or through the proper hepatic artery. RESULTS: Twenty-seven (82%) patients completed planned chemoradiotherapy. Nausea was the most frequent complaint. No patient experienced Grade 4 toxicities. More than half achieved pain relief. As for the primary site, only 4 patients (12%) achieved a partial response at 4 weeks; however, 3 additional patients attained >50% tumor reduction thereafter. The most frequent site of disease progression was the liver, and only 3 patients developed local progression alone. No regional lymph nodal progression outside the treatment field was seen. Median survival time and survival at 1 year were 7.1 months and 27%, respectively, for the entire group. Difference in overall survival between patients with and without distant metastases was significant (p = 0.01). CONCLUSIONS: Involved-field irradiation with concurrent daily CDDP was well tolerated without compromising locoregional effects.

Abdominal Pain↗
PubMed2005

Differences in pulmonary function before vs. 1 year after hypofractionated stereotactic radiotherapy for small peripheral lung tumors.

PURPOSE: To evaluate long-term pulmonary toxicity of stereotactic radiotherapy (SRT) by pulmonary function tests (PFTs) performed before and after SRT for small peripheral lung tumors. METHODS AND MATERIALS: A total of 17 lesions in 15 patients with small peripheral lung tumors, who underwent SRT between February 2000 and April 2003, were included in this study. Twelve patients had primary lung cancer, and 3 patients had metastatic lung cancer. Primary lung cancer was T1-2N0M0 in all cases. Smoking history was assessed by the Brinkman index (number of cigarettes smoked per day multiplied by number of years of smoking). Prescribed radiation doses at the 80% isodose line were 40-60 Gy in 5-8 fractions. PFTs were performed immediately before SRT and 1 year after SRT. Test parameters included total lung capacity (TLC), vital capacity (VC), forced expiratory volume in 1 s (FEV1.0), and diffusing capacity of lung for carbon monoxide (DLCO). PFT changes were evaluated in relation to patient- and treatment-related factors, including age, the Brinkman index, internal target volume, the percentages of lung volume irradiated with >15, 20, 25, and 30 Gy (V15, V20, V25, and V30, respectively), and mean lung dose. RESULTS: There were no significant changes in TLC, VC, or FEV1.0 before vs. after SRT. The mean percent change from baseline in DLCO was significantly increased by 128.2%. Univariate and multivariate analyses revealed a correlation between DLCO and the Brinkman index. CONCLUSIONS: One year after SRT as compared with before SRT, there were no declines in TLC, VC, and FEV1.0. DLCO improved in patients who had been heavy smokers before SRT, suggesting a correlation between DLCO and smoking cessation. SRT seems to be tolerable in view of long-term lung function.

Aged↗
PubMed2003

Fatal infectious mononucleosis with evidence suggestive of the development of B cell lymphoma.

A 4-year-old girl presented to a local hospital in August 1999 with fever and cervical lymphadenopathy. A diagnosis of Epstein-Barr virus (EBV) infection was made and the patient was treated with corticosteroids. One month later she developed dyspnea secondary to tonsilar swelling, and underwent tonsillectomy and adenoidectomy. Her dyspnea increased, however, and by mid September she required mechanical ventilation. Six weeks later, she was transferred to Chiba Children's Hospital (Chiba, Japan). Despite vigorous treatment, she died within four weeks of admission. At autopsy, microscopic examination revealed numerous histiocytes with frequent hemophagocytosis in her lungs, liver, spleen, thymus, and lymph nodes. The tentative diagnosis was EBV-associated hemophagocytic syndrome (EBVAHS). A proliferation of atypical lymphocytes was observed in the lymph nodes, the majority of which stained positive with CD79a antibody. A whitish nodule, 8 mm in diameter, was noted in her right ovary. It consisted of a proliferation of pleomorphic lymphoid cells expressing CD79a antigen. In situ hybridization detected EBV RNA within CD79a antigen-positive cells in the lungs, spleen, thymus, bone marrow, lymph nodes, and the right ovary. Polymerase chain reaction analysis of DNA from the ovarian nodule demonstrated a monoclonal rearrangement of the immunoglobulin heavy chain gene indicating that it consisted of a clone of B lymphocytes. We suggest that EBVAHS develops into polyclonal and monoclonal lymphoproliferative disorder in a short period, and that EBVAHS is a preneoplastic condition that may result in B cell lymphoma.

Adenoidectomy↗
PubMed2003

Radiation-induced chromosome aberrations in ataxia telangiectasia cells: high frequency of deletions and misrejoining detected by fluorescence in situ hybridization.

The mechanisms underlying the hyper-radiosensitivity of AT cells were investigated by analyzing chromosome aberrations in the G(2) and M phases of the cell cycle using a combination of chemically induced premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) with chromosome painting probes. Confluent cultures of normal fibroblast cells (AG1522) and fibroblast cells derived from an individual with AT (GM02052) were exposed to gamma rays and allowed to repair at 37 degrees C for 24 h. At doses that resulted in 10% survival, GM02052 cells were approximately five times more sensitive to gamma rays than AG1522 cells. For a given dose, GM02052 cells contained a much higher frequency of deletions and misrejoining than AG1522 cells. For both cell types, a good correlation was found between the percentage of aberrant cells and cell survival. The average number of color junctions, which represent the frequency of chromosome misrejoining, was also found to correlate well with survival. However, in a similar surviving population of GM02052 and AG1522 cells, induced by 1 Gy and 6 Gy, respectively, AG1522 cells contained four times more color junctions and half as many deletions as GM02052 cells. These results indicate that both repair deficiency and misrepair may be involved in the hyper-radiosensitivity of AT cells.

Ataxia Telangiectasia↗
PubMed2003

Consolidation radiotherapy following brief chemotherapy for localized diffuse large B-cell lymphoma: a prospective study.

Many physicians administer involved field radiation therapy (RT) following brief chemotherapy for localized aggressive non-Hodgkin's lymphoma. Involved field irradiation usually implies treatment to the involved nodal regions with and without the contiguous lymphatic region, however, there is no agreements about its definition. Here we assess the appropriateness of RT irrespective of lymph node regions (localized field) following chemotherapy for patients with early stage diffuse large B-cell lymphoma. The localized field encompassed all original gross tumor volumes before chemotherapy with at least a 2- to 3-cm margin irrespective of lymphatic regions. We also evaluated the suitable radiation dose on the basis of response to chemotherapy. Twenty five eligible patients were treated with 3 cycles of chemotherapy (CHOP) followed by RT. All 25 patients had disease confined to Waldeyer's ring and/or cervical lymph nodes. Twenty two patients in complete response following chemotherapy received 30 Gy, and the remaining 3 in partial response received 40 Gy. With a median follow up of 42 months, both event free and overall survival rates at 2 years were 96.0%. There were no in-field recurrences, however, two patients experienced relapses. One developed central nervous system involvement and subsequently died of his disease. The other had mediastinal and submental lymph node relapse at 32 months, and is alive after salvage chemotherapy. Our study demonstrated that it should be possible to reduce treatment volume to less than the conventional involved field, and to limit the dose of RT in the range of 30-40 Gy.

Adult↗
PubMed2003

MR imaging study of edema-like change along the optic tract in patients with pituitary region tumors.

BACKGROUND AND PURPOSE: Edema-like change along the optic tract commonly occurs in association with craniopharyngiomas. The aim of this study was to clarify whether it occurs in association with other common pituitary region tumors and to elucidate its mechanism as seen on MR images. METHODS: Fifty patients with pituitary region tumors that were touching or compressing the optic pathway underwent heavily T2-weighted MR imaging before and after treatment. RESULTS: Edema-like change along the optic tract was visible on the images of four of 25 pituitary adenomas, eight of 11 craniopharyngiomas, one germ cell tumor, and one malignant lymphoma and was not visible on the images of seven meningiomas and five Rathke's cleft cysts. After therapeutic decompression of the optic pathway, the edema-like change disappeared and large Virchow-Robin spaces, present under normal conditions, became visible along the optic tract. Comparison of pre- and post-treatment coronal and axial view MR images revealed that the edema-like change had been located at, along, and/or around the large Virchow-Robin spaces along the optic tract. CONCLUSION: Edema-like change occurs in association with pituitary region tumors other than craniopharyngiomas. It is related with distension of normally present large Virchow-Robin spaces adjacent to the optic tract. Because Virchow-Robin spaces are speculated to be a drainage route of interstitial fluid into the subarachnoid space, their distension may be related to the fluid retention in and along the Virchow-Robin spaces, the outlet of which into the subpial and/or subarachnoid space(s) is blocked by pituitary region tumors.

Adenoma↗
PubMed2002

VH gene analysis in sporadic Burkitt's lymphoma: somatic mutation and intraclonal diversity with special reference to the tumor cells involving germinal center.

We analyzed the immunoglobulin heavy chain variable region (V(H)) gene in seven cases of sporadic Burkitt's lymphoma (sBL) to elucidate their cell of origin. In particular, we focused on the V(H) gene status of tumor cells involving adjacent germinal center (GC) by microdissecting histological sections. Among the seven V(H) genes V(H)1 family was found in two, V(H)3 in four, and V(H)4 in one. All rearranged V(H) genes demonstrated somatic mutations at percentages ranging from 1.4 to 7.5% (mean, 4.2%), which is a similar level to that seen in IgM-only B cells. Three out of four V(H) genes with more than 2% sequence difference from their corresponding germline counterpart showed evidence of antigen selection in their framework region 3. Three cases demonstrated signs of intraclonal diversity with a mutational frequency of 0.47-0.98%, which was 13.5-28.8 times as great as the Taq infidelity in our experimental conditions. However the level of somatic mutation and the effect of antigen selection on V(H) gene were diverse in these three cases, and the relationship between V(H) gene somatic mutation status and intraclonal diversity was unclear in sBL. In the analysis of microdissected tissues, all 20 tumor clones in the adjacent GCs showed additional replacement mutations in complementarity determining region 3, suggesting a role of antigen in tumor progression. This finding resembles the phenomenon that memory B-cells reenter into GC to undergo further affinity maturation. In contrast, 7/11 V(H) gene sequences irrelevant to GC were identical to those of the major tumor clone. Thus our findings suggested that sBL is derived from memory B-cells rather than GC B-cells, and that antigen stimulation is involved in the clonal expansion of a proportion of sBL.

Amino Acid Sequence↗
PubMed2002

Diffuse pulmonary involvement by mycosis fungoides: high-resolution computed tomography and pathologic findings.

The authors report the high-resolution computed tomography (HRCT) appearance of diffuse pulmonary involvement by mycosis fungoides in a 74-year-old woman whose clinical and radiographic manifestations simulated pneumonia. The HRCT showed multiple, dense, peribronchovascular nodules with surrounding ground-glass opacity and several wedge-shape peripheral opacities. The autopsy specimen revealed angiocentric and peribronchovascular involvement of mycosis fungoides and pulmonary infarctions distal to angiocentric infiltration of the tumor cells.

Aged↗