Search PubMed⌕ Search

Biomedical subjects

M Sasaki

Publications and source records attributed to M Sasaki.

At least 289 records · Page 16Linked to original sources
PubMed2000

Vascular endothelial growth factor-driven glioma growth and vascularization in an orthotopic rat model monitored by magnetic resonance imaging.

OBJECTIVE: The goal of the present study was to develop an orthotopic in vivo model for the investigation of vascular endothelial growth factor (VEGF)-dependent glioma growth and vascularization. METHODS: C6 glioma cells were infected with viruses encoding sense or antisense VEGF. Expression of the transgene was controlled by Northern blot analysis, Western blot analysis, and immunohistochemistry. Spheroids generated from both clones as well as from wild-type and mock-transfected cells were implanted in the brains of Sprague-Dawley rats. Growth and vascularization were assessed using magnetic resonance imaging after 7 and 11 days. Histology was studied using hematoxylin and eosin staining, immunohistochemistry with anti-von Willebrand staining, anti-VEGF, anti-CD8, and assessment of vessel density. RESULTS: Cell proliferation, migration, and invasion in vitro were very similar in all cell clones. Sense gliomas demonstrated by far the fastest growth in vivo, with intense contrast enhancement meeting criteria for highly malignant tumors. Histological examination revealed masses of von Willebrand- and VEGF-positive tumor vessels with a high vessel density. Antisense gliomas depicted the radiological features of low-grade gliomas, with slow growth and poor vascularization, although they were highly infiltrative. Wild-type and mock-transfected gliomas demonstrated similar growth and vascularization patterns intermediate between sense and antisense gliomas. Any influence of the allogeneic response of the hosts on different tumor sizes could be excluded. CONCLUSION: Our model elucidates glioma growth and vascularization as strongly VEGF dependent, which is consistent with human gliomas. Thus, this model is suitable for testing antiangiogenic strategies to interfere with the VEGF/VEGF receptor system, as well as for exploring VEGF-independent mechanisms using the antisense-transfected clone.

Animals↗
PubMed2000

Focal fatty infiltration in the posterior aspect of hepatic segment IV: relationship to pancreaticoduodenal venous drainage.

OBJECTIVE: We aimed to investigate the relationship between fatty infiltration in the posterior aspect of hepatic segment IV and pancreaticoduodenal venous drainage. METHODS: Pancreaticoduodenal arteriography was performed in 21 patients who had nontumorous portal perfusion defects in the posterior aspect of hepatic segment IV, as demonstrated on CT during arterial portography (CTAP). RESULTS: In 10 patients, pancreaticoduodenal arteriography showed an aberrant nonportal vessel with flow toward the hepatic hilum in the venous phase. Four of the 10 patients with nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in segment IV. In three of these four patients, the fatty infiltration was focal and localized to that area. On the other hand, none of the 11 patients without nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in the regions corresponding to the nontumorous portal perfusion defects on CTAP. Moreover, three patients with diffuse fatty liver had a focal nonfatty area in segment IV. CONCLUSIONS: Focal fatty infiltration in the posterior aspect of hepatic segment IV seems to be related to pancreaticoduodenal venous drainage.

Aged↗
PubMed2000

Analysis of TH1 and TH2 cells by intracellular cytokine detection with flow cytometry in patients with ovarian cancer.

OBJECTIVE: Our aim is to assess the immune status of patients with ovarian cancer by analyzing the ratio of T helper type 1 (TH1) to T helper type 2 (TH2) populations in peripheral blood lymphocytes (PBL). METHODS: We examined TH1/TH2 ratios in PBL obtained from 21 ovarian cancer patients who had just received postoperative chemotherapy, by detecting the intracellular IFN-gamma and IL-4 production with 3-color flow cytometry. Additionally, we evaluated the influence of a granulocyte-colony stimulating factor (G-CSF) injection on TH1 and TH2 populations for a rescue of granulocytopenia due to the chemotherapy. RESULTS: We could not find any significant difference of the TH1/TH2 ratios in terms of age, International Federation of Gynecology and Obstetrics (FIGO) clinical stage and clinical tumor status. As for the clinical tumor status, however, the patients with residual cancer had a higher TH1/TH2 ratio, though it was not statistically significant (p = 0. 15). Anticancer chemotherapy is also considered to lead to the immunosuppressive state of the patients. TH1 and TH2 populations of PBL in the patients during chemotherapy showed an unfavorable imbalance that was shifted from TH1 to TH2 10 days after anticancer drug administration (p = 0.049). G-CSF administration, on the other hand, was likely to induce a cell population shift from TH2 to TH1 assessed by the intracellular cytokine assay (p = 0.051), and never induced an unfavorable imbalance from TH1 to TH2 in the T cell population by a 1-day injection of G-CSF. CONCLUSION: Together, these data indicate that the TH1/TH2 ratio analyzed by intracellular cytokine flow cytometry seems to be a good indicator to assess the immune status in cancer.

Adult↗
PubMed2000

Effect of follicle-stimulating hormone on sertoli cell division in cultures of fetal rat testes.

The present study was performed to determine when follicle-stimulating hormone (FSH) begins to promote Sertoli cell division in fetal rats, and to determine whether the effect of FSH is mediated by cAMP-dependent protein kinase (PKA). When testes from 15- to 17-day fetuses were cultured with or without FSH for 48 h, FSH did not promote Sertoli cell division in 15-day testes, but did in 16- and 17-day testes. Anti-rat FSH was injected into 16-day fetuses in utero. Twenty-four hours later, the testes of the injected fetuses and those of their intact littermates were cultured with or without FSH for 48 h. Without FSH, the Sertoli cell division index was significantly lower in anti-FSH-treated fetuses than in intact fetuses. With FSH, however, the index increased. When PKA inhibitor was added to cultures of 16-day testes with FSH, the promotion of Sertoli cell division by FSH was inhibited. We conclude that between 16 and 17 days of gestation, fetal pituitary FSH stimulates the division of Sertoli cells by activating the PKA activity.

Animals↗
PubMed2000

Adaptation of the muscles of mastication to the flat skull feature in the polar bear (Ursus maritimus).

The muscles of mastication of the polar bear (Ursus maritimus) and those of the brown bear (U. arctos) were examined by anatomical approach. In addition, the examination of the skull was carried out in the polar bear, brown bear and giant panda (Ailuropoda melanoleuca). In the polar bear, the rostro-ventral part of the superficial layer of the M. masseter possessed the abundant fleshy portion folded in the rostral and lateral directions like an accordion. Moreover, the rostro-medial area of the superficial layer became hollow in the nuchal direction when the mouth was closed. The M. temporalis of the polar bear covered up the anterior border of the coronoid process of the mandible and occupied the almost entire area of the cranial surface. The M. pterygoideus medialis of the polar bear was inserted on the ventral border of the mandible and on the ventral part of the temporal bone more widely than that of the brown bear. As results of our measurements of the mandible, an effect of the leverage in the polar bear was the smallest in three species. In the polar bear, the skull was flat, and the space between zygomatic arch and ventral border of the mandible, occupied by the M. masseter was the narrowest. It is suggested that the muscles of mastication of the polar bear is adapted to the flat skull feature for supplementing the functions.

Animals↗
PubMed2000

Geographical variation of mandible size and shape in the Japanese wild pig (Sus scrofa leucomystax).

The mandibles of the Japanese wild pigs (Sus scrofa leucomystax) from various geographical locations, which have been stored in the University of Tokyo and National Science Museum, Tokyo were examined. The mandibles from northern localities were larger in size than those from southern localities. The Oita population was significantly smaller than the Honshu populations. The Mie population was smaller than the Hyogo population in length from the angle of the mandible. In the multivariate analysis, the Kyushu populations could be obviously distinguished from the Honshu populations in the principal component charts. However, each Honshu population did not show the locality-specific distribution of the principal component plots.

Animals↗
PubMed2000

Relationship between the pixel value in digital subtraction angiography and iodine concentration: study in high iodine concentration with original phantom.

Quantitative digital subtraction angiography (DSA) image analysis based on densitometry is widely accepted and used. For the densitometoric DSA image analysis, it is required that there is a linear relationships between the pixel values on DSA images (DSA values) and contrast medium iodine concentration or the thickness of the vessels or the chambers filled with contrast material. We studied on relationship between the DSA value and iodine concentration especially in high iodine concentration. As for the relationship between DSA values and iodine concentration on the DSA images at low concentration, DSA phantom had a good linear relationship. However, the relationship at the high iodine concentration, DSA phantom sometimes lost this linear relationship. Our results suggested that it was necessary to identify relationship between DSA values and iodine concentration in each DSA system, especially in high iodine concentration setting, for densitometoric DSA image analysis.

Angiography↗
PubMed2000

Meningitis carcinomatosa originating from an alpha fetoprotein-producing gastric cancer.

Alpha fetoprotein (AFP)-producing gastric cancer is relatively rare and meningitis carcinomatosa is similarly a rare manifestation among the neoplastic diseases. There have been no previous reports of meningitis carcinomatosa originating from AFP-producing gastric cancer. A 68-year-old man with AFP-producing gastric cancer was treated with cisplatin and doxifluridine because of multiple liver metastases. Although the liver lesion was reduced to 30% of pretreatment size after 6 courses of chemotherapy, meningitis carcinomatosa subsequently occurred. Immunostaining of AFP and magnetic resonance imaging (MRI) were useful in the diagnosis of meningitis caused by AFP producing cancer cells.

Adenocarcinoma↗
PubMed2000

Intraductal papillary mucinous tumors of the pancreas: thin-section helical CT findings.

OBJECTIVE: The purpose of this study was to evaluate the thin-section helical CT findings of intraductal papillary mucinous tumors and to investigate whether helical CT could distinguish between malignant and benign intraductal papillary mucinous tumors. MATERIALS AND METHODS: Twenty-seven patients (nine with malignant and 18 with benign intraductal papillary-mucinous tumors) underwent thin-section (3- or 5-mm) helical CT. Two-phase enhanced CT was started 30 and 60-70 sec after injection of contrast material at 3 ml/sec. RESULTS: In six patients (22.2%), a bulging papilla was depicted on CT. Twenty-five patients (92.6%) had a dilated main pancreatic duct. Cystic lesions were seen in 25 patients (92.6%). Thirteen lesions (48%) were located in the uncinate process, seven (25.9%) were in the head, two (7.4%) were in the body, and three (11%) were in the tail. The cystic lesion was unilocular in five patients (18.5%) and multilocular with a lobulated margin in 20 patients (74%). Communication between the main pancreatic duct and the cystic lesion was depicted in 19 patients (70.4%). The papillary projections corresponding to 3-mm or larger papillary neoplasms were depicted in five patients (18.5%). The bulging papilla was more often observed in malignant than in benign intraductal papillary mucinous tumors (p < 0.05). The caliber of the main pancreatic duct was significantly larger in patients with malignant intraductal papillary mucinous tumors (p > 0.001). CONCLUSION: The most frequently found feature of intraductal papillary mucinous tumors was a lobulated multilocular cystic lesion located in the uncinate process and in contiguity with the dilated main pancreatic duct. In some patients, a bulging papilla and papillary projections in the ducts, which were specific findings, were visualized on CT. The bulging papilla and the caliber of the main pancreatic duct helped differentiate malignant from benign intraductal papillary mucinous tumors.

Adenocarcinoma, Mucinous↗
PubMed2000

Macroscopic anatomy of the auditory tube diverticulum (guttural pouch) in the thoroughbred equine--a silicon mold approach.

The characteristics of the equine auditory tube diverticulum (guttural pouches) were studied in detail by the naked eye and silicon mold method. First, we examined the anatomical relationship between the guttural pouches and their associated bones and muscles. Secondly, a silicon mold was fabricated to clarify the three-dimensional aspect of the guttural pouches, paying a special attention to the distribution of major arteries and nerves surrounding it. Thirdly, the volume of the silicon mold was measured by immersing it in water. The guttural pouches are a pair of pouches located dorso-posteriorly to the posterior pharynx. The pouches had a close contact rostrally with the Os sphenoidale, ventrally with the pharynx and the esophagus, and caudally with the Articulatio atlantoaxialis. The left and right guttural pouches had almost the same capacity in each horse. The A. carotis interna, cranial ganglia of cervical nerves and cervical Truncus sympathicus, as well as the N. vagus, N. glossopharyngeus, N. hypoglossus, and Radices spinales of the N. accessorius, were present in the mucosal crease extending from the roof of the guttural pouches towards the middle of the caudal wall. The N. facialis appeared from the Foramen stylomastoideum ran dorsocaudally along the lateral recess. The N. mandibularis appeared from the Foramen lacerum went over the muscular process of an ear bone, ran along the roof of the lateral recess and finally continued with the rostral side of the guttural pouches. Lymph nodes, scattered on the mucosal surface, appeared as tiny indentations with approximately millet seed size on the silicon surface. The capacity of guttural pouches in adult horses (472 +/- 12.4 cm3) was three-fold larger than that in foals (145 +/- 9.4 cm3).

Animals↗
PubMed2000

Successful neuroendoscopic third ventriculostomy for hydrocephalus and syringomyelia associated with fourth ventricle outlet obstruction. Case report.

The authors report the use of neuroendoscopic third ventriculostomy to treat successfully both hydrocephalus and syringomyelia associated with fourth ventricle outlet obstruction. A 27-year-old woman presented with dizziness, headache, and nausea. Magnetic resonance (MR) imaging demonstrated dilation of all ventricles, downward displacement of the third ventricular floor, obliteration of the retrocerebellar cerebrospinal fluid (CSF) space, funnellike enlargement of the entrance of the central canal in the fourth ventricle, and syringomyelia involving mainly the cervical spinal cord. Cine-MR imaging indicated patency of the aqueduct and an absent CSF flow signal in the area of the cistema magna, which indicated obstruction of the outlets of the fourth ventricle. Although results of radioisotope cisternography indicated failure of CSF absorption, neuroendoscopic third ventriculostomy completely resolved all symptoms as well as the ventricular and spinal cord abnormalities evident on MR images. Neuroendoscopic third ventriculostomy is an important option for treating hydrocephalus in patients with fourth ventricle outlet obstruction.

Adult↗
PubMed2000

[Long-term complete response in a case of unresectable rectal cancer following chemoradiation].

We report a case of unresectable rectal cancer in a 53-year-old male treated with chemoradiation. Radiation therapy was delivered with a total pelvic dose of 45 Gy together with oral administration of 5'-DFUR (1,200 mg/day). The patient received one course of combination chemotherapy consisting of cisplatin, 100 mg/body x 1 day, and 5-FU, 1,000 mg/body x 5 days, followed by radiation therapy. Oral administration of tegafur-uracil (300 mg/day) was continued for five years following the chemoradiation. The patient is now disease-free 75 months after the initial surgery. Chemoradiation can be managed to obtain a complete remission of some locally advanced rectal cancers.

Adenocarcinoma↗
PubMed2000

[Percutaneous mechanical thrombectomy for thrombosed vessels with a hydrolyser (hydrodynamic thrombectomy catheter): clinical experience].

A hydrodynamic thrombectomy catheter was prospectively evaluated for the treatment of thrombosed vessels. Seven patients (7 males: age range from 56 to 82 years; mean age: 79 years) presenting with acute or chronic occlusion of peripheral native arteries (n = 6) and dialysis shunt (n = 1) were treated with the hydrolyser (Cordis, Johnson and Johnson, Japan). Mean occlusion time was 135 days (range: 2-300 days), and mean thrombus length 16 cm (range: 5-20 cm). Removal of the thrombus was successful in five patients (71%), regardless of the length of the thrombus. Mean procedure time was 20 minutes (range: 15-30 minutes). No major complications occurred. Adjunctive thrombolysis was required for persistence of the residual thrombosed distal vessel in one patient. Adjunctive balloon angioplasty was performed in two patients (one native vessel and one dialysis shunt), and stent placement was performed in one patient (dialysis shunt). In two unsuccessful cases, the hydrolyser could not be advanced to the distal side because of the solid thrombus. Therefore, thrombolytic therapy was chosen. However, this therapy failed because the guidewire did not pass within the thrombus. Surgery was performed in these two patients. We conclude from this clinical experience that percutaneous thrombectomy with a hydrolyser is a promising technique for the treatment of thrombosed vessels. Especially in the acute stage of thrombosed occlusion, percutaneous thrombectomy with a hydrolyser is superior to thrombectomy with a Fogarty balloon catheter because of its shorter procedure time and fewer complications.

Acute Disease↗
PubMed2000

Volume-weighted mean nuclear volume. Is this new prognosticator comparable in different institutions?

OBJECTIVE: To determine whether volume-weighted mean nuclear volume (MNV) obtained at one institution is comparable to that from other institutions. STUDY DESIGN: MNV calculated from histologic slides obtained at three hospitals--Shizuoka Prefectural Hospital (SPH), Shimada Municipal Hospital (SMH) and Shizuoka City Hospital (SCH)--were compared. Between December 1994 and June 1996, transurethral resection of bladder tumor or transurethral resection of the prostate was performed on 37 patients at SPH and 50 patients at SMH; histologic specimens from 40 cases of bladder tumors, 63 cases of normal bladder mucosa, 28 cases of benign prostatic hyperplasia and 1 case of prostate cancer were obtained. A portion of each specimen obtained at SPH or SMH was carried to SCH, and histologic slides were made at SCH using it. Using the remaining position of each specimen, histologic slides were then prepared at each hospital. Estimates of MNV were made from all histologic slides from each hospital, and the differences in MNV between the hospitals were analyzed. In addition, intraobserver and interobserver reproducibility were analyzed using 50 specimens obtained between December 1994 and August 1995. RESULTS: On linear regression analysis, comparison of MNVs calculated from the histologic slides from SPH and SCH and those calculated from SMH and SCH revealed high correlation coefficients (R = .966 and .966, respectively), and the slope of the regression line did not differ significantly from unity. The paired t test also disclosed no significant difference between MNVs calculated at the two hospitals. Furthermore, the correlation coefficients for intraobserver and interobserver reproducibility of MNV estimates were also high (R = .918 and .949, respectively). CONCLUSION: The results of this study indicate that estimates of MNV are comparable in multiple institutions, and we recommend that they be used to support subjective histologic grading.

Cell Nucleus↗
PubMed2000

[Complete remission in a case of sigmoid colon cancer with multiple liver metastases-treatment with arterial chemotherapy and percutaneous microwave coagulation therapy].

A 59-year-old man was admitted to our hospital for advanced sigmoid colon carcinoma with synchronous multiple liver metastases. The patient received sigmoidectomy with regional lymph node dissection on June 8, 1998. We started intra-arterial combination chemotherapy on July 1, 1998. MMC (4 mg/body) was administered via rapid intra-arterial infusion on day 1. After MMC administration, 5-day intra-arterial continuous infusion of 5-FU at 500 mg/body/day was performed with oral administration of LV (30 mg/body/day). The treatment cycle was defined as every three weeks. The patient was treated with 4 courses of chemotherapy. From September 30, he received intra-arterial infusion of bolus MMC 4 mg/body, LV 6 mg/body and 5-FU 1,000 mg/body/4 hrs every two weeks with oral administration of Tegafur-uracil 400 mg/day. After 4 intra-arterial chemotherapy sessions, the metastatic liver tumors disappeared except for a focus in the right lobe. Therefore we decided to give the remnant liver metastasis percutaneous microwave coagulation therapy (PMCT). He obtained a complete remission in the liver metastases after two PMCT (70 W, 60 sec) sessions. Intra-arterial chemotherapy is effective for unresectable metastatic liver tumors from colon cancer. If a patient shows a partial response on the metastatic tumors through the chemotherapy, one must consider other modalities such as PMCT.

Adenocarcinoma↗
PubMed2000

The expansion of the CAG repeat in exon 1 of the human androgen receptor gene is associated with uterine endometrial carcinoma.

Uterine endometrial carcinoma is common among women. Several reports indicated that this cancer is influenced by androgens mediated through their receptors. The human androgen receptor gene contains a polymorphic CAG repeat in the coding region of exon 1. Other studies suggested a possible association between the CAG repeat of this gene and the development of several cancers. DNA samples isolated from 29 patients with sporadic endometrial cancer were analyzed for allelic changes in 12 highly polymorphic microsatellite loci on nine chromosomes, containing CAG repeat in the exon 1 of the androgen receptor gene. A significantly high rate of allelic change in the CAG repeat was observed (51.7%) in these patients, although the frequencies of additional loci were similar to those reported by others (0-22.2%). The changed alleles of the tumor tissue were always longer than that of normal tissue except in only one case. Since only one allele on the X chromosome is commonly active in female cells, a differential methylation assay was carried out by using genomic DNA cut with HpaII. In 14 of 15 cases, we found that the activated allele was longer in these samples from tumor tissues than those from normal tissue; in the remaining case, the length of this repeat was unchanged. The expression assays were done by using poly(A+) RNA from tumor and normal uterine tissues, revealing that an activated allele in these tumor tissues was longer than that in the normal tissues in all the cases examined. These findings suggest that expansions of the CAG repeat in the androgen receptor gene may play an important role in the carcinogenesis of uterine endometrial cells.

Alleles↗