Search PubMed⌕ Search

Biomedical subjects

S Yasuda

Publications and source records attributed to S Yasuda.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Serial angiographical changes of a ruptured dissecting vertebral aneurysm].

A 54-year-old woman presented a subarachnoid hemorrhage from a ruptured dissecting aneurysm on the right vertebral artery. A right vertebral angiogram revealed a fusiform dilatation distal to the right posterior inferior cerebellar artery and "pseudo lumen" was observed in a delayed arterial phase. Conservative treatment was carried out, and the patient condition gradually improved. An angiographical examination for planned endovascular treatment 46 days after the onset, revealed the normalization of the formerly dilated caliber of the right vertebral artery with only a minor luminal irregularity. However, 83 days after the onset, right vertebral angiogram showed reappearance of the fusiform dilatation. The right vertebral angiogram obtained 204 days after the onset showed that the dilated segment of the dissecting aneurysm had become normalized to a slight degree. The serial angiographical changes of the dissecting site might have been due to regression and organization following transient thrombosis of intramural hematoma. Such drastic changes within a short period have not been reported yet. In conclusion, careful repeated follow-up is recommended in monitoring aneurysmal formation during the early to chronic phase after rupture of a dissecting aneurysm. The repetition of angiography is important, because later, if angiography has been performed only once, aneurysmal dilatation may be overlooked. One has to be aware of such changes, because such changes may alter the clinician's decision about treatment, as they did in our case.

Aneurysm, Ruptured↗
PubMed2001

[Optimal lymph node dissection for colorectal cancer].

Previous studies on the distribution of positive lymph nodes have revealed that the colon should be resected 10 cm from the tumor on both sides and that the intermediate nodes along the main vessel should be dissected in patients with colon cancer. In rectal cancer, superior lymphatic spread along the inferior mesenteric artery (IMA) is the main metastatic route. The IMA should be dissected immediately after the bifurcation of the left colic artery, and the intermediate lymph nodes should be removed. The positive rate of the lateral lymph nodes is about 10%. The rate of local failure is high and the prognosis is poor in patients with positive lateral lymph nodes, even if the lateral lymph nodes have been dissected. However, it has been reported that lateral lymph node dissection combined with excision of the internal iliac vessels results in good disease-free survival in patients with positive lateral nodes. Therefore the indications for lateral node dissection remain controversial. Lymphatic spread into the mesorectum on the anal side has been shown to be an important factor in local failure. The mesorectum should be resected for up to 4 or 5 cm from the inferior tumor margin in middle rectal cancer, and the entire mesorectum should be removed in lower rectal cancer. Nerve tissue preserved in pelvic autonomic nerve-preserving surgery contains a small amount of lymphoid tissue and lymph nodes. Therefore the extent of lymph node dissection and the area of autonomic nerves to be preserved based on tumor site or tumor penetration remain controversial.

Colonic Neoplasms↗
PubMed2001

18F-FDG PET detection of colonic adenomas.

UNLABELLED: The adenomatous polyp of the colon is clinically important as a precursor of colonic cancer. The aim of this preliminary study was to evaluate the potential usefulness of (18)F-FDG PET for detecting adenomatous polyps of the colon. METHODS: We performed a retrospective study of 110 subjects who underwent both PET study and total colonoscopy. On nonattenuation-corrected PET images, focal distinct FDG accumulation along the large intestine was considered a positive finding, and the PET results were compared with colonoscopic findings. Histology and adenoma size were determined by polypectomy. RESULTS: Fifty-nine adenomatous polyps, 5-30 mm in size, were found in 30 subjects by total colonoscopy. PET findings were positive for 14 of the 59 adenomas (24%). The positivity rate for PET images rose with the increase in size of the adenomas; it was 90% in adenomas (9/10) that were > or =13 mm. The overall false-positive rate was 5.5% (6/110 subjects). CONCLUSION: Increased glucose metabolism is observed in colonic adenomas, and detectability with PET increases with the increase in adenoma size. Adenomas are premalignant lesions, and it is important to realize that colonic adenomas may be found incidentally during an FDG PET study.

Adenomatous Polyps↗
PubMed2001

Preliminary study for sentinel lymph node identification with Tc-99m tin colloid in patients with esophageal or gastric cancer.

The purpose of this study is to determine whether a lymph node identified with high radioisotope (RI) activity is a sentinel node. We studied 26 patients with either esophageal or gastric cancer whose preoperative imaging studies showed no lymph node metastasis. Before surgery, Tc-99m tin colloid was injected via endoscopy into the submucosa. In lymph nodes dissected at surgery, RI activity was measured by a scintillation counter, and metastatic status was examined by hematoxylin-eosin staining. The number of dissected nodes was 45 +/- 15 (mean +/- SD) per patient, and the number of nodes with high RI activity was 4 +/- 1. Nodal metastasis occurred in 11 of 26 patients. In 9 of these 11 patients, metastatic foci were found in one or more nodes with high RI activity. In one of the 2 remaining patients, endoscopic clipping was applied just above the injection sites, and in the other patient, the tumor invasion was beyond the muscle layer. For further analysis, the case with clipping was excluded, and only those in which the tumor invasion was confined within the muscle layer were evaluated. Six of 18 patients in this analysis showed nodal metastasis. Each of the 6 patients had at least one node that showed high RI activity and that was positive for metastasis. We conclude that when tumor invasion remains within the muscle layer, lymph nodes with high RI activity can be regarded as sentinel nodes.

Aged↗
PubMed2001

[Continuous epidural administration of droperidol for the prevention of postoperative nausea].

Continuous antiemetic effect of epidural droperidol was evaluated by prospective, double-blinded study using 145 ASA physical status I-II patients undergoing major gynecological surgery. All patients received bolus epidural infusion of buprenorphine at the end of the operation and continuous epidural infusion of buprenorphine for 48 hours. Patients were divided into 3 groups, 49 patients of Group I received placebo, 50 patients of Group II received only bolus doses of droperidol 2.5 mg and the remaining 46 patients of Group III received continuous epidural infusion of droperidol 10 mg in 48 hours. Visual analogue scales for nausea, the incidence of emetic episodes and side effects were evaluated at 3 hr, 24 hr and 48 hr postoperatively. The scores for nausea were significantly lower in Group III (P < 0.05) compared with Group I 24 hr after the operation. The incidence of emesis was significantly lower in Group III (P < 0.05) as compared with Group I and II 48 hr after the operation. Extrapyramidal side effects and sedative effects were not observed in any patients. The continuous epidural administration of droperidol is effective in prevention of postoperative nausea and vomiting and the effect lasts during its infusion with no side effects.

Analgesia, Epidural↗
PubMed2001

Expression of METH-1 and METH-2 in pancreatic cancer.

PURPOSE: METH-1/hADAMTS-1 and METH-2/hADAMTS-8 are recently identified genes that inhibit angiogenesis, and the murine homologue, ADAMTS-1, shows metalloproteinase function. Because the significance of METH-1 and METH-2 has not been determined in solid tumors, we examined the mRNA expressions of these molecules in pancreatic cancer and hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN: METH-1 and METH-2 mRNA expressions were identified in six pancreatic cancer cell lines and were quantified by TaqMan reverse transcription-PCR in 18 paired samples of pancreatic cancer and surrounding noncancerous pancreas, and in 14 samples of pancreatic cancer. METH-1 mRNA expression was also examined in 16 pairs of HCC and cirrhotic liver. Vascularity was estimated by CD34 staining. The correlation between clinicopathological factors and METH-1 expression was additionally analyzed. RESULTS: Four of six pancreatic cancer cell lines expressed METH-1, and 1/6 expressed METH-2. METH-1 was substantially expressed in both pancreatic cancer and noncancerous pancreas, but METH-2 was not. METH-1 expression in pancreatic cancer tissue was significantly lower than that in noncancerous pancreas (P = 0.002), and a similar result was obtained between HCC and cirrhotic liver (P = 0.003). METH-1 expression did not show a significant correlation with vascularity in pancreatic cancer or in HCC. However, pancreatic cancer with higher expression of METH-1 showed significantly severe lymph node metastasis or retroperitoneal invasion (P = 0.033 and P = 0.018, respectively) and worse prognosis (P = 0.038). CONCLUSIONS: METH-1, which was initially reported to have a potent antiangiogenic effect, does not seem to be a predominant determinant of tumor vascularity in pancreatic cancer. Rather, METH-1 seems to be involved in progression of pancreatic cancer through local invasion and lymph node metastasis.

ADAM Proteins↗
PubMed2001

[A case of advanced gastric cancer producing alpha fetoprotein with multiple liver metastases responding to TS-1 after TAE].

We report a case of advanced gastric cancer producing Alpha Fetoprotein (AFP) with multiple liver metastases in which TS-1 is effective. Prognosis of gastric cancer producing AFP is well known to poor. A 74-year-old female was admitted complaining of anemia. She was diagnosed as having advanced gastric cancer with multiple liver metastases producing AFP by endoscopy, computed tomography and angiography. Her serum AFP level was 17,666 ng/ml and her serum CEA level was 5-2 ng/ml. After transarterial embolization (TAE), her family rejected her operation because it would not be curative. So, she was treated with TS-1, 40 mg, administered orally every day, followed by 14 days rest, as the first course. The next was TS-1, 80 mg orally administered for 6 courses. Her serum AFP level was down from 17,666 ng/ml to 94 ng/ml after 6 courses of TS-1. CT revealed that liver metastases did not change and endoscopy showed the primary lesion has diminished. Our report is the first to demonstrate that TS-1 is effective for patients with advanced gastric cancer producing AFP with multiple liver metastases.

Adenocarcinoma↗
PubMed2001

A case of duodenal involvement of multiple myeloma imaged by positron emission tomography with 18F-fluorodeoxyglucose.

A 61-year-old woman had been treated for multiple myeloma for 4 years when she developed abdominal pain. Ultrasonography and computed tomography revealed a tumor in the abdomen. Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) showed increased FDG uptake in the tumor. In previous bone marrow lesions, which were in clinical remission after chemotherapy and radiotherapy, abnormal FDG uptake was not recognized. Pathological examination after surgery revealed the tumor to be a plasmacytoma of the duodenum. Plasmacytoma of the duodenum is rare but can be seen during the clinical course of multiple myeloma. A few reports have described FDG PET findings of plasmacytoma. Those previous reports and our present case suggest a potential value of FDG PET in the evaluation of multiple myeloma.

Duodenal Neoplasms↗
PubMed2001

[Bone metabolic markers and osteoporosis associated with diabetes mellitus].

Diabetes mellitus has been documented to affect bone and calcium metabolism. However, there is conflicting data on the frequency of fractures, changes of bone mineral density and the levels of bone metabolic markers in diabetes. These results may be related to heterogeneity of the patients in the studies, i.e., the presence or absence of insulin injection, body mass index, the amounts of intrinsic insulin secretion and/or insulin resistance. The combination of poor bone quality and frequent injurious falls would be expected to increase fracture incidence and a recent report revealed that older women with diabetes had a particularly increased risk of fractures. The metabolic effects of poor glycemic control lead to increased bone resorption without sufficient bone formation. With respect to bone metabolic markers, decreased levels of osteocalcin (OC) have been commonly reported. It is not known whether decreased OC is a predictive factor for fractures in diabetes, but the osteocalcin levels have been found to return toward the normal range after glycemic control. Since OC is known to be glycosylated, it is also possible that the measurement would be affected by high glucose conditions. The exact value of bone metabolic markers in diabetes has not been established, but measurement of osteocalcin may be a useful tool for evaluation of risk of fractures in diabetic patients.

English Abstract↗
PubMed2001

[Appropriate clinical usage of calcitonin escape phenomenon and intermittent v.s. daily administration of calcitonin].

Since Calcitonin (CT) inhibits osteoclastic bone resorption, it has been widely used to treat metabolic bone disorders, such as Paget's disease of bone, malignancy-associated hypercalcemia, and osteoporosis. It is recognized, however, that continuous treatment with CT causes a loss of its inhibitory effects on bone resorption. We and other investigators have studied the mechanism and the results indicated that desensitization to CT was closely associated with the down regulation of the CT receptor (CTR). This down regulation was due not only to internalization of the receptor but also to reduced cell surface receptor concentration through inhibition of de novo CTR synthesis. An essential signal for osteoclast differentiation from its precursor cells, which was termed as ODF, was also found identical to tumor necrosis factor (TNF) related activation induced cytokine (TRANCE) and receptor activator of nuclear factor-kappa B ligand (RANKL). Using soluble RANKL and macrophage colony stimulating factor, we recently studied the mechanisms of the biological responses to CT in cells of human osteoclast lineage. The signaling pathway responsible for CTR down regulation in human osteoclasts is different from that observed in mouse osteoclasts: the activation of protein kinase A pathway is primarily responsible for CTR regulation in mouse osteoclasts, while the activation of protein kinase C was predominant in humans. Treatment with CT reduced concentration of cellular surface CTR and CTR mRNA expression also in human osteoclasts. The reduced specific binding, CTR mRNA levels and CT-sensitive adenylate cyclase responsiveness returned to the control levels by 96h after removal of CT. These results may suggest that intermittent administration of CT would be effective for the treatment of osteoporosis, resulting in reduced desensitization in CT target cells.

English Abstract↗
PubMed2000

Reconstitution of ATP- and cytosol-dependent transport of de novo synthesized ceramide to the site of sphingomyelin synthesis in semi-intact cells.

Transport of ceramide synthesized at the endoplasmic reticulum to the Golgi compartment, where sphingomyelin (SM) synthase exists, was reconstituted within semi-intact Chinese hamster ovary cells. When [(3)H]ceramide that had been produced from [(3)H]sphingosine at 15 degrees C in perforated cells was chased at 37 degrees C, [(3)H]ceramide-to-[(3)H]SM conversion occurred in a cytosol-dependent manner. In various aspects (i.e. kinetics, ATP dependence, and temperature dependence), [(3)H]ceramide-to-[(3)H]SM conversion in perforated cells was consistent with that in intact cells. The cytosol from LY-A strain, a Chinese hamster ovary cell mutant defective in endoplasmic reticulum-to-Golgi transport of ceramide, did not support [(3)H]ceramide-to-[(3)H]SM conversion in perforated wild-type cells, whereas the wild-type cytosol rescued the conversion in perforated LY-A cells. Brefeldin A-treated cells, in which the endoplasmic reticulum and the Golgi apparatus were merged, no longer required cytosol for conversion of [(3)H]ceramide to [(3)H]SM. These results indicated that the assay of [(3)H]ceramide-to-[(3)H]SM conversion in semi-intact cells is a faithful in vitro assay for the activity of cytosol-dependent transport of ceramide and that LY-A cells are defective in a cytosolic factor involved in ceramide transport. In addition, conversion of [(3)H]ceramide to [(3)H]glucosylceramide in semi-intact cells was little dependent on cytosol, suggesting that ceramide reached the site of glucosylceramide synthesis by a cytosol-independent (or less dependent) pathway.

Adenosine Triphosphate↗
PubMed2000

Target volume definition for upper abdominal irradiation using CT scans obtained during inhale and exhale phases.

PURPOSE: To evaluate the clinical utility of a treatment-planning technique involving the use of CT images obtained during both the static exhalation phase and static inhalation phase (two-phase planning). METHODS AND MATERIALS: Ten patients with pancreatic or liver tumors underwent CT scanning under static exhale and inhale conditions, after a period of mild ventilation. By setting image positions differently, we were able to treat the two-phase images as one dataset. Each gross tumor volume (GTV) was contoured separately and the mixed GTV was used for the two-phase treatment planning. Treatment plans were constructed to compare the two-phase plans with the plans constructed using static exhalation images. The shift of the center of the GTV and kidneys and the minimum dose of GTV were then calculated. RESULTS: The shift of the GTV ranged from 2.6 to 27. 3 mm and that of the kidneys from 2.2 to 24 mm. In some patients whose treatment was planned using exhalation planning, the minimum dose of GTV at inhalation was less than 90% of the isocenter dose. CONCLUSION: Two-phase planning is a simple technique that can visualize tumor and organ movement simultaneously using CT. It further defines adequate field margins around the tumor and prevents unexpected radiation exposure to critical organs. Routine use of this technique for upper abdominal irradiation is recommended.

Abdominal Neoplasms↗
PubMed2000

Coagulation and fibrinolytic activities in 2 siblings with beta(2)-glycoprotein I deficiency.

beta(2)-Glycoprotein I (beta(2)GPI) is a major antigen for antiphospholipid antibodies, and its multiple in vitro functions have been reported. This glycoprotein not only down-regulates thrombin formation by inhibiting contact activation or prothrombinase activity, but also up-regulates coagulation by reducing protein C anticoagulant activity. However, the in vivo roles of beta(2)GPI remain obscure. Coagulation and fibrinolytic characteristics were investigated in individuals with beta(2)GPI deficiency. An apparently healthy woman and her brother are homozygotes for beta(2)GPI deficiency. In these patients, Russell viper venom time was shortened (40.4 seconds; normal range, 47.8 +/- 4.95 seconds), but all markers of thrombin generation and fibrin turnover were within normal ranges. Exogenous activated protein C adequately prolonged the clotting time of the beta(2)GPI-deficient plasma, and euglobulin lysis time was also normal. Thus, elevated thrombin generation, enhancement of activated protein C response, and an altered fibrinolytic system were not found in congenitally beta(2)GPI-deficient plasma. (Blood. 2000;96:1594-1595)

Adult↗
PubMed2000

Single low-dose administration of human recombinant hepatocyte growth factor attenuates intimal hyperplasia in a balloon-injured rabbit iliac artery model.

BACKGROUND: Previous studies have shown that repeated systemic administration of human recombinant hepatocyte growth factor (hrHGF) in mg/kg levels modulates the wound-healing process in various diseases. Recently, HGF has been characterized as one of the most potent endothelial-cell-specific growth factors. We tested our hypothesis that local delivery of hrHGF, even at low microg/kg levels (> or =2 orders of magnitude lower than systemically administered doses), might attenuate neointimal hyperplasia in response to vascular injury via accelerated reendothelialization. METHODS AND RESULTS: The iliac artery was denuded in 16 New Zealand White rabbits (3 kg), followed by administration, via a drug delivery catheter, of either hrHGF (10 microg; n = 11) or control vehicle (n=5) over 20 minutes. In pilot studies using this device, the drug permeated into the medial tissues, where it persisted for > or =24 hours. Four weeks after the local delivery of hrHGF, computer-assisted morphometric analysis revealed significant reduction in the intimal area (hrHGF, 0.37+/-0.21 versus control, 0.68+/-0.16 mm(2), mean +/- SD; P<0.05) but no change in the medial area (hrHGF, 1.03+/-0.21 versus control, 1.10+/-0.52 mm(2)). Scanning electron microscopy revealed extensive endothelialization with regular and confluent endothelial cell layer regeneration in the hrHGF-treated vessels. CONCLUSIONS: Accelerated endothelialization after local delivery of hrHGF, a novel and potent endothelial cell mitogen, effectively attenuates neointimal proliferation even after single low-dose administration. This observation could have potential therapeutic implications in the prevention of restenosis after angioplasty.

Animals↗
PubMed2000

Transcriptional regulation of HIV-1 LTR during antigen-dependent activation of primary T cells by dendritic cells.

Numerous factors are known to bind human immunodeficiency virus (HIV) long terminal repeat (LTR) and activate viral transcription, but little is known as to how they function in naturally activated T cells and to what extent their binding is relevant to HIV replication in vivo. To characterize the HIV LTR-binding factors responsible for antigen-dependent activation of HIV, we examined replication of LTR mutant viruses in CD4+ T cells activated by different stimuli. NF-kappaB or Sp1 mutant virus replicated well in CD4+ T cells activated by phorbol ester and calcium ionophore. When they were activated by antigen-pulsed dendritic cells, the replication of the Sp1-deleted virus was severely impaired in CD45RA+, but not in CD45RO+ T cell subsets that dominantly produce interleukin-2 (IL-2). Stimulation via CD3/CD28 induced a high level of IL-2 production in both T cell subsets, but Sp1-deleted virus poorly replicated in CD45RA+ subset. The level of NF-kappaB and Sp1-binding factors did not differ between these subsets. Our results suggest that additional cofactors distinct from IL-2-inducing signaling molecules are important for LTR activation during antigen-dependent T cell activation.

Antigen Presentation↗
PubMed2000

Characterization of audiogenic-like seizures in naive rats evoked by activation of AMPA and NMDA receptors in the inferior colliculus.

The role of glutamate receptors in the inferior colliculus (IC) in audiogenic and audiogenic-like seizures was investigated in adult rats with transient neonatal hypothyroidism by 0.02% propylthiouracil (PTU) treatment through mother's milk (PTU rats) and in naive rats treated intracisternally with N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic acid (AMPA), or cyclothiazide, an inhibitor of rapid AMPA receptor desensitization. All rats showed audiogenic or audiogenic-like seizures characterized by running fit (RF) and generalized tonic-clonic seizures (GTCS). While systemically administered MK-801 inhibited GTCS, intracisternally administered NBQX inhibited RF and GTCS in both audiogenic and audiogenic-like seizures. Auditory stimulation shortened the latency to GTCS induced by AMPA, but not NMDA, at a subclinical dose and further elongated the shortened duration of RF, but not GTCS, induced by MK-801 pretreatment. Furthermore, Northern blot analysis was used to evaluate the expression of the immediate-early gene c-fos in the IC following induction of audiogenic or audiogenic-like seizures. The significant induction of c-fos mRNA by audiogenic seizures in PTU rats or by AMPA- or cyclothiazide-induced seizures in naive rats was prominent in the IC. MK-801 suppressed c-fos mRNA expression in the IC induced by audiogenic seizures in PTU rats or by AMPA-induced seizures in naive rats. NBQX suppressed the expression of c-fos mRNA in the IC induced by AMPA-induced seizures but did not suppress c-fos mRNA in PTU rats or rats with cyclothiazide-induced seizures. Auditory stimuli failed to affect c-fos mRNA induction by AMPA. The present study suggests that audiogenic-like seizures can be reproduced by glutamate receptor agonists in which AMPA receptors are primarily linked to the initiation of audiogenic seizures (RF) while NMDA receptors presumably located within the IC are involved in the propagation of GTCS in audiogenic seizures.

Acoustic Stimulation↗