PubMed Health⌕ Search

Biomedical subjects

I Sakamoto

Publications and source records attributed to I Sakamoto.

At least 19 recordsLinked to original sources
PubMed2003

Mutations in the ST7/RAY1/HELG locus rarely occur in primary colorectal, gastric, and hepatocellular carcinomas.

Human cancers frequently show a loss of heterozygosity on chromosome 7q31, which indicates the existence of broad-range tumour-suppressor gene(s) at this locus. Truncating mutations in the ST7 gene at this locus are seen frequently in primary colon cancer and breast cancer cell lines. Therefore, the ST7 gene represents a novel candidate gene for the tumour suppressor at this locus. However, more recent studies have reported that ST7 mutations are infrequent or absent in primary cancer and cell lines. To ascertain the frequency of mutations of the ST7 gene in cancer cells, we examined mutations in the ST7 coding sequence in 48 colorectal, 48 gastric, and 48 hepatocellular carcinomas using polymerase chain reaction-single-strand conformational polymorphism and direct sequencing. We detected somatic mutations, which were located near the exon-intron junction in intron 8, in only three out of 144 cases. We conclude that mutations in the ST7 gene are rare in primary colorectal, gastric, and hepatocellular carcinomas.

Bacterial Proteins↗
PubMed2003

Intramucosal adenocarcinoma of the appendix: how to find and how to treat.

A colonoscopic examination of a 58-year-old man revealed a small elevated lesion inside the orifice of the appendix. Using a polypectomy snare, a nodular polypoid lesion with a diameter of ca. 20 mm was removed from the lumen of the appendix. Histopathology showed that it was a well-differentiated adenocarcinoma. This is the first report of an intramucosal adenocarcinoma of the appendix diagnosed preoperatively; laparoscopy-assisted colectomy with a D2 lymph-node dissection was carried out. Endoscopists should consider an appendiceal tumor when an erosion, elevation, or deformity is seen in the head of the cecum.

Adenocarcinoma↗
PubMed2001

Immunohistochemical and electron microscopic study of extrinsic hepatic reinnervation following orthotopic liver transplantation in rats.

BACKGROUND/AIMS: Because little has been known about the morphological and functional consequences of liver transplantation on hepatic autonomic nerves, we examined the time-course of extrinsic hepatic innervation at the level of the porta hepatis of liver allografts. METHODS: Orthotopic liver transplantation was performed using male Lewis rats. Crosscut tissue specimens were obtained postoperatively for up to 6 months from the porta hepatis of transplanted livers, and processed for immunohistochemical staining for protein gene product 9.5 (PGP 9.5) and growth-associated protein 43 (GAP-43), and for transmission electron microscopy (TEM). RESULTS: Extrinsic nerve fibers at the porta hepatis stained positively for PGP 9.5 throughout the entire study period. In contrast, the immunoreactivity of GAP-43 was negative at postoperative day (POD) 1 and 2. GAP-43-positive nerves were first observed to appear in the porta hepatis at POD 3. The immunoreactivity of GAP-43 remained positive thereafter until 3 months post-OLT, and became negative in all the specimens at 4 months post-OLT. Transmission electron microscopy demonstrated a small number of regenerating axons existing among many degenerating axons at POD 3. At 3 months post-OLT, most regenerating axons had been fully ensheathed by the cytoplasm of Schwann cells, although their density remained at a lower level compared with normal. CONCLUSION: The results of this study suggest that liver allografts become extrinsically reinnervated, with the regenerating axons reaching the hepatic hilus 3 days after transplantation. The process of extrinsic hepatic reinnervation is considered to almost terminate 4 months after transplantation in rats.

Animals↗
PubMed2001

Evaluation of pancreatic secretion after administration of secretin: application of magnetic resonance imaging.

BACKGROUND: To evaluate pancreatic exocrine function, we measured the changes in T2 enhanced hydrograhic intensity on magnetic resonance (MR) images of the pancreas following an injection of secretin, which is representative of the changes in duodenal fluid volume. METHODS: The subjects were 10 patients with normal pancreatic function (N > 70% detected by using a pancreatic function diagnostant test) and 12 patients with hypo-function, including those with mild hypo-function (MH, 50-70%, six patients) and severe hypo-function (SH < 50%, six patients). RESULTS: In the N group, T2 enhanced intensity of the pancreas increased to a maximum value (more than 10% compared with baseline) within 5 min of stimulation, then gradually decreased. No significant difference in the response was observed between the head and body of the pancreas. Changes in the MH group were similar to those of the N group. In contrast, significantly lower changes in T2 enhanced intensity were observed in SH group, relative to both the N and MH group (P < 0.05). The amount of secretin-induced increase in duodenal fluid after 16 min was not significantly different among the three groups. Furthermore, an evaluation of the residual pancreatic tissue after a pancreatoduodenectomy was also feasible. CONCLUSIONS: Our results indicate that the MR-secretin test is useful for the evaluation of severe pancreatic exocrine dysfunction. The diagnostic test is simple, direct and non-invasive.

Adult↗
PubMed2001

Fibrous adhesions in the joint compartment of the temporomandibular joint associated with experimental opposite drawing mandibular ramus in rabbit.

The purpose of this study was to develop a rabbit model of fibrous adhesions in the joint compartment of the temporomandibular joint (TMJ) without surgical invasion into the joint compartment. A unilaterally elastic force of about 120 grams was applied from the anterior edge of masseteric tuberosity to the posterior part of the zygomatic arch between the masseteric fascia layer and the subcutaneous layer in 14 rabbits. The blocks of nondrawing side TMJ were removed after four weeks. Fibrous adhesions were observed in 13 rabbits except for one rabbit that lost over 30% of its body weight. In eight of the rabbits, the adhesions were detected in both joint compartments. This animal model for fibrous adhesion of the TMJ will be useful in understanding the pathogenesis of adhesion in human TMJs.

Animals↗
PubMed2001

Suppressive effect of Lactobacillus gasseri OLL 2716 (LG21) on Helicobacter pylori infection in humans.

To examine the efficacy of Lactobacillus gasseri OLL2716 (LG21) as a probiotic for Helicobacter pylori in humans, 31 subjects infected with the bacterium ingested yogurt containing LG21 daily for an 8 week period. The [(13)C]urea breath test and assays of serum pepsinogens revealed a significant improvement following LG21 treatment. LG21 was thus determined to be effective in both suppressing H. pylori and reducing gastric mucosal inflammation.

Female↗
PubMed2001

Inhibition of the Wnt signaling pathway by Idax, a novel Dvl-binding protein.

In attempting to clarify the roles of Dvl in the Wnt signaling pathway, we identified a novel protein which binds to the PDZ domain of Dvl and named it Idax (for inhibition of the Dvl and Axin complex). Idax and Axin competed with each other for the binding to Dvl. Immunocytochemical analyses showed that Idax was localized to the same place as Dvl in cells and that expression of Axin inhibited the colocalization of Dvl and Idax. Further, Wnt-induced accumulation of beta-catenin and activation of T-cell factor in mammalian cells were suppressed by expression of Idax. Expression of Idax in Xenopus embryos induced ventralization with a reduction in the expression of siamois, a Wnt-inducible gene. Idax inhibited Wnt- and Dvl- but not beta-catenin-induced axis duplication. It is known that Dvl is a positive regulator in the Wnt signaling pathway and that the PDZ domain is important for this activity. Therefore, these results suggest that Idax functions as a negative regulator of the Wnt signaling pathway by directly binding to the PDZ domain of Dvl.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[CT-guided needle biopsy of the lung: factors affecting risk of complications].

PURPOSE: To analyze factors influencing the risk of complications associated with CT-guided percutaneous needle biopsy for lung lesions. MATERIALS AND METHODS: Sixty patients, aged 24-85 years (37 men and 23 women), underwent CT-guided needle biopsy. A definite diagnosis was made in 49 of 60 cases (81.7%), including 38 of 43 malignant lesions (88.4%) and 11 of 17 benign lesions (64.7%). Complications associated with biopsy were observed in 35 patients (58.3%). Major complications included pneumothorax (n = 26) and pulmonary hemorrhage (n = 20). Chest tube placement was needed in 5 (19.2%) of 26 pneumothorax cases (8.3% of all biopsies). RESULTS: The high frequency of pneumothorax (43.3%) in this series had several contributing factors, including the presence of pulmonary emphysema, lesion size, and traversal of aerated lung. Chest tube replacement was necessary more frequently in patients with pulmonary emphysema. The number of pleural passes, location of lesions, and size of needles were not correlated with the incidence of pneumothorax. CONCLUSION: The presence of pulmonary emphysema, lesion size, and traversal of aerated lung are the predominant risk factors for pneumothorax in patients with CT-guided lung biopsy.

Adult↗
PubMed2001

A model for internal derangement and osteoarthritis of the temporomandibular joint with experimental traction of the mandibular ramus in rabbit.

OBJECTIVES: The purpose of this study is to make a model of internal derangement (ID) and osteoarthritis (OA) by postero-superior displacement of the mandible in the rabbit temporomandibular joint (TMJ). MATERIALS AND METHODS: Sixteen Japanese white rabbits (8 months old) were subjected to traction of the mandibular ramus in the postero-superior direction unilaterally using elastic force and five rabbits were used as the control. The operations were performed without surgical invasion of the TMJ capsule. Temporomandibular joint tissue was removed after 4 weeks and Technovit and paraffin sections with or without decalcification were observed histologically. RESULTS: In contrast to the control group, it showed anterior disc displacement, disc deformity, resorption of subchondral bone and osteophyte formation in the drawing side of the experimental group. Intra-articular fibrous adhesions were observed in both sides. CONCLUSION: It is concluded that posterosuperior displacement of the mandible caused ID and OA in the rabbit TMJ. This model may contribute to the understanding of the etiology of human temporomadibular disorders (TMD).

Animals↗
PubMed2000

A novel beta-catenin-binding protein inhibits beta-catenin-dependent Tcf activation and axis formation.

beta-Catenin is efficiently phosphorylated by glycogen synthase kinase-3beta in the Axin complex in the cytoplasm, resulting in the down-regulation. In response to Wnt, beta-catenin is stabilized and translocated into the nucleus where it stimulates gene expression through Tcf/Lef. Here we report a novel protein, designated Duplin (for axis duplication inhibitor), which negatively regulates the function of beta-catenin in the nucleus. Duplin was located in the nucleus. Duplin bound directly to the Armadillo repeats of beta-catenin, thereby inhibiting the binding of Tcf to beta-catenin. It did not affect the stability of beta-catenin but inhibited Wnt- or beta-catenin-dependent Tcf activation. Furthermore, expression of Duplin in Xenopus embryos inhibited the axis formation and beta-catenin-dependent axis duplication, and prevented the beta-catenin's ability to rescue ventralizing phenotypes induced by ultraviolet light irradiation. Thus, Duplin is a nuclear protein that inhibits beta-catenin signaling.

Amino Acid Sequence↗
PubMed2000

An evaluation of Bosniak's radiological classification of cystic renal masses.

OBJECTIVE: To determine the clinical usefulness of Bosniak's classification of cystic renal masses, the differentiation of which remains difficult despite significant advances in diagnostic imaging. PATIENTS AND METHODS: The computed tomography (CT) findings of all histopathologically examined cystic renal masses diagnosed at our institution were analysed retrospectively; 35 patients with cystic renal masses were treated between 1986 and 1998. Tissues surgically removed were examined pathologically and the final diagnosis compared with the preoperative CT category of Bosniak's classification. RESULTS: The histopathological examined showed cystic renal cell carcinoma in 21 patients, a benign renal cyst in 12, haemangiosarcoma in one and transitional cell carcinoma in one. Most of the 35 masses (26, 74%) were found incidentally during evaluation for an unrelated disease or a routine health check. All 11 masses of Bosniak category I were benign and one category II mass was malignant. All 10 masses of category III and 12 of category IV were malignant. CONCLUSIONS: Bosniak's classification is useful for differentiating category I, III and IV cystic renal masses. There were too few samples to allow meaningful conclusions to be drawn for category II renal masses. It is critical to differentiate between complicated cysts of category II and III because of the major implications for prognosis and clinical management.

Adult↗
PubMed2000

Symptomatic peripheral vascular tree stenosis. Comparison of subtracted and nonsubtracted 3D contrast-enhanced MR angiography with fat suppression.

OBJECTIVE: To determine the clinical feasibility of contrast-enhanced three-dimensional (3D) MR angiography (MRA) with fat suppression spectral inversion at lipids and to compare subtracted and nonsubtracted images. MATERIAL AND METHODS: In 13 patients suspected of having lower extremity ischemia, 3D dynamic contrast-enhanced MRA of the iliac and femoral arteries was performed using the fat suppression technique. The validity of the MRA interpretations of the degree of stenoses was evaluated by comparing with conventional angiography as the gold standard. The contrast-to-noise (C/N) ratios of both subtracted and nonsubtracted maximum-intensity-projection (MIP) images were calculated. RESULTS: In the arteries with stenosis of 50% or greater, the sensitivity and specificity of the subtracted MR angiograms were 100% and 96.5%, respectively, not significantly different from the corresponding values in nonsubtracted MRAs (100% and 94.1%, respectively). The C/N ratios of the subtracted images were significantly higher than those of the nonsubtracted images (p<0.001). CONCLUSION: With this technique, fat suppression can be performed with only a slight increase in the examination time. A lower dose of contrast material can be used in MRA with fat suppression than without it. Subtracted MRA improves the ease of interpretation compared to nonsubtracted MRA.

Aged↗
PubMed2000

Comparison of the effectiveness of arthrocentesis in acute and chronic closed lock: analysis of clinical and arthroscopic findings.

The objective of this study was to investigate the effectiveness of temporomandibular joint arthrocentesis in acute and chronic closed lock patients. Eighteen patients with closed lock of the temporomandibular joint (TMJ) were treated with fine needle fiber arthroscopic observation following arthrocentesis. Maximal mouth opening (MMO) and intensity of pain (VAS) were evaluated at pretreatment and each posttreatment appointment (one week, one month, three months following treatment). The clinical and arthroscopic findings were analyzed categorizing two groups into: good (A) and poor (B) groups. At pretreatment there was no significance relative to age or the mean MMO and VAS between the groups, but the mean of duration of the symptoms in group B was significantly longer than in group A (P < 0.03). Group B showed more severe synovitis, adhesions, and chondromalacia than group A (P < 0.01). Results suggest that arthrocentesis is more effective in closed lock of short duration where there is less severe synovitis, adhesions, and chondromalacia.

Acute Disease↗