Biomedical subjects

K Yamashita

Publications and source records attributed to K Yamashita.

At least 19 recordsLinked to original sources

PubMed2006

Intraoperative detection of cell injury and cell death with an 800 nm near-infrared fluorescent annexin V derivative.

The intraoperative detection of cell injury and cell death is fundamental to human surgeries such as organ transplantation and resection. Because of low autofluorescence background and relatively high tissue penetration, invisible light in the 800 nm region provides sensitive detection of disease pathology without changing the appearance of the surgical field. In order to provide surgeons with real-time intraoperative detection of cell injury and death after ischemia/reperfusion (I/R), we have developed a bioactive derivative of human annexin V (annexin800), which fluoresces at 800 nm. Total fluorescence yield, as a function of bioactivity, was optimized in vitro, and final performance was assessed in vivo. In liver, intestine and heart animal models of I/R, an optimal signal to background ratio was obtained 30 min after intravenous injection of annexin800, and histology confirmed concordance between planar reflectance images and actual deep tissue injury. In summary, annexin800 permits sensitive, real-time detection of cell injury and cell death after I/R in the intraoperative setting, and can be used during a variety of surgeries for rapid assessment of tissue and organ status.

Animals↗

PubMed2006

Comparison of the transcutaneous oxygen and carbon dioxide tension in different electrode locations during general anaesthesia.

BACKGROUND AND OBJECTIVE: The best place for the electrode of transcutaneous measurement of oxygen tension (tcPO2) and carbon dioxide tension (tcPCO2) during general anaesthesia was investigated in three different locations. METHODS: Fifteen patients for major abdominal surgery in the supine position were studied. The electrode of the TCM4 (Radiometer, Copenhagen, Denmark) was put on the chest, upper arm or forearm. TcPO2, tcPCO2, end-tidal carbon dioxide tension (etCO2), percutaneous oxygen saturation (SaO2), arterial oxygen tension (PaO2 ) and arterial carbon dioxide tension (PaCO2) were simultaneously measured at four different etCO2 concentrations and inhaled oxygen percentages and the location of the electrode was changed to other places to repeat the same measurement. In total, 12 measurements for each patient and 60 measurements for each place were performed. RESULTS: TcPO2 correlated better than SaO2 (R2 = 0.58) with PaO2 (R2 = 0.76), and tcPCO2 correlated well with PaCO2 (R2 = 0.76) and etCO2 (R2 = 0.74) when the electrode was put on the chest, while not on the upper arm or forearm (R2 < 0.5). However, limits of agreement were too big to use tcPO2 (bias, -67.9; limits of agreement, 16.5, -152.3) and tcPCO2 (bias, -0.47; limits of agreement, 8.7, -9.64) as surrogate measures of PaO2 and PaCO2, respectively even when the electrode was put on the chest. CONCLUSIONS: When the electrode was put on the chest, tcPO2 and tcPCO2 might be available as non-invasive monitors of oxygenation and CO2 status during general anaesthesia, while the absolute values were not interchangeable with PaO2 and PaCO2, respectively.

Aged↗

PubMed2006

A single amino acid in the RNA-dependent RNA polymerase of Plantago asiatica mosaic virus contributes to systemic necrosis.

From a lily isolate of Plantago asiatica mosaic virus (PlAMV-Li), two sub-isolates (Li1 and Li6) were obtained. Although the nucleotide sequences of Li1 and Li6 were highly conserved, they showed different pathogenicity in Nicotiana benthamiana. Li1 caused necrosis, whereas Li6 infected the plant asymptomatically. Inoculation tests with chimeric and point-mutated viruses revealed that amino acid 1154 of the RNA-dependent RNA polymerase (RdRp) contributes to the necrotic symptoms. The accumulation of the mutant viruses, in which amino acid 1154 of the RdRp was exchanged to the wild-type codon in Li1 and Li6, was almost equal.

Amino Acids↗

PubMed2006

Pleomorphic adenoma of the salivary gland in two dogs.

Pleomorphic adenomas of the salivary gland were diagnosed in two dogs. The tumours were single, firm and well circumscribed, with a smooth cut surface. Metastatic tumours were not detected. Histopathological examination revealed that the tumours contained multiple cysts lined with luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues. Immunohistochemical examination demonstrated labelling of luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues with antibodies to cytokeratin LU-5, AE1/AE3, CK-14, CALP, a-SMA, vimentin, GFAP, and S-100. Labelling for GFAP indicated stromal transformation into myxoid and chondroid tissues.

Adenoma, Pleomorphic↗

PubMed2006

Effect of electrical polarization of hydroxyapatite ceramics on new bone formation.

Large surface charges can be induced on hydroxyapatite (HAp) ceramics by proton transport polarization, but this does not affect beta-tricalcium phosphate (TCP) because of its low polarizability. We wished to examine differences in osteogenic cell activity and new bone growth between positively or negatively surface-charged HAp and HAp/TCP plates using a calvarial bone defect model. In the first group of rats, test pieces were placed with their positively charged surfaces face down on the dura mater. In the second group, test pieces were placed with their negatively charged surfaces face down on the dura mater. A third group received noncharged test pieces. Histological examination, including enzymatic staining for osteoblasts and osteoclasts, was carried out. While no bone formation was observed at the pericranium, direct bone formation on the cranial bone debris and new bone growth expanded from the margins of the sites of injury to bridge across both the positively and negatively charged surfaces of HAp and HAp/TCP plates occurred. Electrical polarization of implanted plates, including positive charge, led to enhanced osteoblast activity, though decreased osteoclast activity was seen on the positively charged plate surface. Thus, polarization of HAp ceramics may modulate new bone formation and resorption.

Animals↗

PubMed2006

The complete nucleotide sequence of attenuated onion yellow dwarf virus: a natural potyvirus deletion mutant lacking the N-terminal 92 amino acids of HC-Pro.

The complete nucleotide sequence of a severe isolate of Onion yellow dwarf virus contains 10,459 nucleotides encoding 3,403 amino acids, while that of an attenuated isolate contains 10,183 nucleotides encoding 3,311 amino acids. The sequence coding for the N-terminal 92 amino acids of HC-Pro was missing in the attenuated isolate. Interestingly, garlic plants growing in commercial gardens were co-infected with isolates of both types. This is the first report of a natural potyvirus deletion mutant lacking the N-terminal region of HC-Pro.

Base Sequence↗

PubMed2006

Effect of adoptive transfer of antigen-specific B cells on periodontal bone resorption.

BACKGROUND AND OBJECTIVES: Host immune responses to periodontal pathogens have been considered to contribute to the alveolar bone destruction in periodontitis. However, the role of B lymphocytes in the pathogenesis of periodontal bone loss is not clear. METHODS: We examined the effect of adoptive transfer of antigen-specific B cells from rat spleens on experimental periodontal bone resorption. Donor rats were immunized intraperitoneally (i.p.) with formalin-killed Actinobacillus actinomycetemcomitans. Antigen-specific B cells were prepared from splenocytes by first binding CD43(+) cells to Petri dishes coated with anti-CD43 antibody to remove T cells, and non-binding cells were passed through a nylon wool column to deplete accessory cells. The retained cells were then collected and bound to A. actinomycetemcomitans-coated Petri dishes for enrichment of A. actinomycetemcomitans-binding B cells (AAB). A. actinomycetemcomitans non-binding B cells (ANB) and B cells from non-immunized donor rats (NIB) were also collected from these procedures. Each type of B cell was injected into a group of recipient rats that were then orally infected with live A. actinomycetemcomitans. RESULTS: At termination, the antibody levels to A. actinomycetemcomitans in serum and gingival wash fluids were significantly higher in the recipients transferred with AAB when compared to the recipients transferred with ANB or NIB. A markedly elevated number of antibody-forming cells were observed in the spleens of the recipients transferred with AAB, and these recipient rats also exhibited significantly increased bone resorption when compared to the other groups. CONCLUSIONS: It is suggested that B cells can contribute to periodontal bone resorption and that antigen-triggering of B cells is required for the bone resorption.

Actinobacillus Infections↗

PubMed2006

Simultaneous colorectal and liver resections for synchronous colorectal metastases.

BACKGROUND: The surgical strategy for the treatment of colorectal cancer and synchronous hepatic metastases remains controversial. Many surgeons fear anastomotic leakage and intraperitoneal abscesses when performing a one-step procedure. They prefer a two-step procedure with a liver resection 2 to 3 months after resection of the colorectal primary lesion. SUBJECTS AND METHODS: We analysed medical records from April 1994 to April 2002 for a total of 42 patients with colorectal cancer and synchronous liver metastases who underwent simultaneous liver and colorectal resections with a primary anastomosis. Special attention was paid to data on surgical procedures, postoperative morbidity, and mortality. RESULTS: Forty-two patients, 24 men and 18 women, were studied. Median operating time was 6.50 hours (3.75-11.0 hours), and median blood loss was 1522 ml (range 288 to 5650 ml). Postoperative complications included pleural effusion in 4 patients, ileus in 3, anastomotic leakage in 2, intraperitoneal pelvic abscesses in 1, pneumonia in 1, bile leakage in 1, atelectasis in 1, and wound infection in 1. There was no perioperative mortality. CONCLUSION: Simultaneous colorectal resection with a primary anastomosis and hepatectomy for synchronous liver metastases is considered a safe procedure.

Adult↗

PubMed2006

[Successful surgical management of papillary muscle rupture following acute myocardial infarction in an elderly patient].

Papillary muscle rupture is rare but catastrophic complication of acute myocardial infarction. We report a 91-year-old woman who underwent successful management of papillary muscle rupture following acute myocardial infarction. She was transferred to our hospital because of severe pulmonary edema and cardiogenic shock. Echocardiography revealed severe mitral valve regurgitation due to total rupture of anterolateral papillary muscle. After intubation, intraaortic balloon pumping (IABP) and percutaneous cardiopulmonary support (PCPS) insertion, mitral valve replacement was successfully performed. She was discharged 134 days after operation. In papillary muscle rupture deteriorating hemodynamics, early diagnosis and immediate cardiopulmonary support are required before surgical treatment. She was, to the best of our knowledge, the oldest among the reported cases of successful surgical treatment of papillary muscle rupture in Japan.

Aged, 80 and over↗

PubMed2005

Cystadenoma of the liver with ovarian-like stroma: case report.

Cystadenomas are rare benign tumors with malignant potential. A 36-year-old woman presented with a 20-cm cystic mass in the left lobe of the liver. Surgery confirmed the diagnostic imaging findings. We present a case of cystadenoma of the liver with ovarian-like stroma and its associated radiologic characteristics.

Adult↗

PubMed2005

Complete nucleotide sequences of attenuated and severe isolates of Leek yellow stripe virus from garlic in northern Japan: identification of three distinct virus types in garlic and leek world-wide.

We have determined the complete nucleotide sequence of three isolates (two severe and one attenuated) of the potyvirus Leek yellow stripe virus (LYSV), the main causal agent of the garlic mosaic disease that is prevalent in Aomori prefecture, northern Japan. They contained 10,296-10,297 nucleotides and encoded a deduced polyprotein of 3,215 amino acids. Sequence variation among the three isolates was 1.5% at both the nucleotide and amino acid levels. Surprisingly, the sequences of all three isolates were quite different from that of recently described garlic isolate of LYSV from China. Sequence similarities among the 5'-UTR and P1 regions were only 56-57% and 52-53%, respectively, raising the possibility that these isolates may actually be distinct virus species. Phylogenetic analyses using 5'-UTR, P1 protein and coat protein revealed that all LYSV isolates described to date can be divided into three groups; i.e., those from leek, those from garlic in northern Japan, and those from garlic in southern Japan, China, and other parts of the world. The garlic isolates from northern Japan were more closely related to LYSV isolates from leek than to garlic isolates from southern Japan and China, suggesting a different origin for the garlic cultivars now cultivated in northern Japan.

5' Untranslated Regions↗

PubMed2005

[Successful treatment of bronchial mucoepidermoid carcinoma by bronchoplasty].

A 63-year-old man who was pointed out abnormal shadow on chest X-ray admitted to our hospital. Chest computed tomography (CT) showed a tumor originated from right upper bronchus and grew into right main bronchus. The tumor was diagnosed as mucoepidermoid carcinoma by bronchoscopic biopsy. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed abnormal uptake localized at the tumor. The standardized uptake values of the tumor 60 minutes after injection were 2.86, and 120 minutes after injection, it increased to 3.97. Right upper lobectomy with bronchoplasty by deep wedge resection of right main bronchus at the orifice of right upper bronchus and lymphadenectomy was performed. Pathological diagnosis was high-grade mucoepidermoid carcinoma without lymph nodes metastasis which was compatible with FDG-PET. Postoperative course was uneventful.

Bronchi↗

PubMed2004

Clinical significance of the overexpression of the candidate oncogene CYP24 in esophageal cancer.

BACKGROUND: By using array comparative genomic hybridization (CGH), the increased copy number of CYP24 (which encodes vitamin D 24-hydroxylase) at 20q13.2 was previously reported, leading to the identification of CYP24 as a candidate oncogene in breast cancer. CYP24 leads to abrogate growth control mediated by vitamin D. MATERIALS AND METHODS: We examined CYP24 expression as well as VDR (vitamin D receptor) gene expression in 42 esophageal cancer cases using semi-quantitative RT-PCR assay. We induced CYP24 in seven esophageal cancer cell lines using 25-hydroxyvitamin D3 [25(OH)D3] and compared cell growth rate, measured using the 3-(4, 5-dimethylthiazol-2-y)-2, 5-diphenyltetrazolium bromide (MTT) assay system. RESULTS: The overall survival rate was significantly higher in 25 cases of lower CYP24 expression than 17 cases of higher CYP24 expression (P <0.05); on the other hand, 23 cases of low VDR expression had a poorer prognosis than 19 cases of high VDR expression. Moreover, we disclosed that the inverse correlation between CYP24 and VDR expression is significant in esophageal cancer cases (P <0.05). Furthermore, the cell growth evaluated by MTT assay was greatly increased in CYP24-induced and VDR-diminished cells than non-responding cells by 25(OH)D3 activity (P <0.01). CONCLUSIONS: Overexpression of the candidate oncogene CYP24 is inversely correlated to vitamin D receptor expression, and may play an important role in determination of the malignant potential of esophageal cancer.

Adult↗

PubMed2004

[Spinal cord protection and operative results of the thoracoabdominal aortic aneurysm].

The purpose of this study was to review retrospectively recent results in 75 patients undergoing thoracoabdominal aortic operations using the technique of distal aortic perfusion with segmental aortic clamping. Between July 1997 and November 2003, 46 males (61%) and 29 females (39%) were treated. The patients ranged in age from 26 to 82 (mean 63 +/- 13) years. Indications for surgery included dissecting thoracoabdominal aortic aneurysm (n = 28), atherosclerotic thoracoabdominal aortic aneurysm (n = 46), and traumatic aneurysm (n = 1). Emergency operation was performed in 8 (11%). The extent of aneurysm was Crawford type I in 12 patients, type II in 19, type III in 34, and type IV in 10. Profound hypothermic circulatory arrest was used in 3 patients and retrograde segmental clamping technique in 5. Cerebrospinal fluid drainage and naloxone hydrochloride administration were performed as adjunctive methods since February 2000. There were 6 (8%) in-hospital deaths. The overall incidence of postoperative paraplegia or paraparesis was 8% (6/75). Although the survival rate has improved, the problem of a complete prevention of ischemic spinal cord injury on the thoracoabdominal aortic operations remains unsolved. The multimodality approach is needed to reduce the risk of this devastating complication.

Adult↗

PubMed2004

[Total arch replacement with reconstruction of non-coronary sinus for acute type A aortic dissection after previous coronary artery bypass grafting; report of a case].

A 73-year-old man, who underwent coronary artery bypass grafting (CABG) 2 years previously, had suffered from acute type A aortic dissection with concomitant mild to moderate aortic regurgitation. A median resternotomy was performed. Arterial and venous cannulae were inserted into the femoral artery and vein to institute a cardiopulmonary bypass. The intimal tear was existed just above the sino-tubular junction. As the non-coronary sinus was involved in the dissection severely, it was resected in a scallop-shaped configuration. The aortic graft was tailored accordingly and anastomosis was performed in a curviliner fashion following the edge of scallop and the horizontally between the right and left coronary sinuses. Next, total arch replacement was performed using an aortic arch branched graft. Postoperative course was uneventful. Aortography revealed no aortic regurgitation and good patency of bypass graft.

Acute Disease↗

PubMed2003

Possible alternative carcinogenesis pathway featuring microsatellite instability in colorectal cancer stroma.

Differential microsatellite instability (MSI) in tumour epithelial and stromal compartments has not been well examined for colorectal cancers. Using laser-captured microdissection, separate specimens of these compartments of 40 sporadic colorectal cancers were sampled and MSI was tested with four markers. To examine the relation between the MSI phenotype in the stroma and other genetic events and histopathological features, p53 and K-ras gene mutations were analysed, and the expression of p53, hMLH1, and hMSH2 protein was determined by immunohistochemistry. Microsatellite instability positive results were obtained for both epithelium (34%) and stromal tissue (41%). While MSI in epithelium correlated with differentiation and Dukes' stage, that in stroma demonstrated an inverse relation, being particularly frequent in well-differentiated adenocarcinomas (54%) and Dukes' A lesions (55%). Further, a significant inverse correlation between p53 protein overexpression in the epithelium and MSI in the stroma was found (P=0.02475). The results suggest an alternative pathway of carcinogenesis involving stromal genetic instability in the development of colorectal cancers.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Response to preoperative chemotherapy affects prognosis in esophageal cancer.

The effect of preoperative chemotherapy on prognosis is still controversial. We have investigated the relationship between responses to preoperative chemotherapy and prognosis after curative operations in patients with esophageal squamous cell carcinoma. Thirty-nine patients received preoperative chemotherapy with continuous infusion of 500 mg/m2 of 5-fluorouracil (5-FU) and intravenous injection of 20 mg/m2 of leucovorin every 12 hours for 5 days. On the 5th day alone, 70 mg/m2 of cisplatin was also infused. The effect was evaluated approximately 14 days after the end of one course of chemotherapy. The rates of responders and non-responders were 64.1% and 35.9%, respectively. After an interval of 21-28 days, transthoracic esophagectomy was performed. Significant histological effect by chemotherapy was found in responders compared to non-responders (P < 0.05). Responders had a significantly better prognosis than non-responders by Log-rank test (P < 0.01). This suggests that preoperative chemotherapy may contribute to better prognosis when the tumor is sensitive to chemotherapy.

Adult↗

PubMed2003

Endoscopic mucosal resection scissors for the treatment of early gastric cancer.

Endoscopic mucosal resection (EMR) is currently a common treatment for superficial gastrointestinal tumors. We have developed new EMR scissors for superficial lesions in the esophagus and stomach. These scissors have stainless steel blades with an electrocoagulation device for hemostasis. We report a case in which superficial gastric cancer was treated by means of the EMR scissors. The lesion was removed using the scissors and no major complication was encountered. EMR scissors can be used for endoscopic resection of superficial lesions of the esophagus and stomach.

Aged↗