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Biomedical subjects

S Yamamoto

Publications and source records attributed to S Yamamoto.

At least 163 records · Page 9Linked to original sources
PubMed2002

[A report of initial clinical use of left ventricular assist system with left ventricular inflow cannula for acute myocardial infarction].

Previous clinical results of left ventricular assist system (LVAS) therapy for cardiogenic shock due to acute myocardial infarction (AMI) are still unacceptable. Japanese LVAS was designed for left atrial inflow cannulation. However, to obtain higher initial LVAS flow and more decompression of left ventricular (LV) cavity and to avoid thromboembolic event, LV inflow cannulation is a preferable procedure. Therefore, LV inflow cannula for Japanese LVAS (Toyobo) was developed. We treated three AMI cases with Toyobo-LVAS using the new LV inflow cannula. All patients were in cardiogenic shock status since broad antero-septal AMI and treated with percutaneous cardio-pulmonary support before the LVAS installation. The LVAS was effective for recovery from cardiogenic shock status and multiple organ failure. Two patients died because of serious LVAS associated complications such as bleeding (case 1, 8 days) and cerebral thromboembolism (case 2, 45 days). One of them was assisted for 202 days and underwent second operation. Sixty days after removal of LVAS, the patient died due to sepsis. The technique of LV inflow cannulation is improved through our experiences. However, our result suggests that renovation of the regimen for anti-coagulation and anti-septic therapy are necessary.

Aged↗
PubMed2002

Effect of an Na+/H+ exchange inhibitor, SM-20550, on ischemic preconditioning in rabbits.

The effects of SM-20550 [N-(aminoiminomethyl)-1,4-dimethyl-1H-indole-2-carboxamide methanesulfonic acid], an Na+/H+ exchange inhibitor, on ischemic preconditioning (IPC) were studied in a rabbit model of myocardial ischemia and reperfusion injury. Anesthetized rabbits underwent occlusion of the coronary artery (30 min) followed by reperfusion (5 h). In SM-20550-treated animals, SM-20550 was intravenously administered at 0.03 mg/kg or 0.1 mg/kg before ischemia (30 min). Treatment with SM-20550 at 0.03 mg/kg had a nonsignificant tendency to reduce infarct size (18%). In contrast, 0.1 mg/kg of SM-20550 significantly reduced infarct size by 62%. In animals with IPC, the condition was induced by 2 or 5 min of ischemia and 10 min of reperfusion prior to sustained ischemia (30 min). Although 5 min of IPC significantly reduced infarct size by 72%, 2 min of IPC reduced infarct size by only 27%, which was not significant. The combination of 5 min of IPC and 0.1 mg/kg of SM-20550 significantly reduced infarct size by 78%. This reduction in infarct size was similar to that produced by 0.1 mg/kg SM-20550 or 5 min of IPC alone. Moreover, the combination of 2 min of IPC and 0.03 mg/kg of SM-20550 significantly reduced infarct size by 64%, although neither 0.03 mg/kg SM-20550 nor 2 min of IPC alone reduced infarct size significantly. These results indicate that an Na+/H+ exchange inhibitor SM-20550, does not antagonize the cardioprotective effect of IPC. SM-20550 and IPC appeared to act synergistically to exert a combined cardioprotective effect.

Amidines↗
PubMed2002

[Endobronchial brachytherapy for intra-luminal recurrence after lung cancer resection].

A 63-year-old man who had squamous cell carcinoma in left lung was received left lower lobectomy with lymph node dissection (pT3N0M0). Twenty months after surgery, the patient showed bloody sputum and bronchofiberscopy revealed intra-luminal recurrence on trachea. Endobronchial brachytherapy in combination with external beam radiotherapy was selected and complete remission was achieved. After the brachytherapy, bronchitis was observed and was healed 23 months after the therapy.

Brachytherapy↗
PubMed2002

[Surgical treatment of two cases with Marfan syndrome].

We report 2 cases of aortic disease with Marfan syndrome underwent surgery. Case 1 was 38-years-old man and case 2 was 36-years-old woman. They were brothers and they had 8 times operation for 13 years. Surgical procedure included aortic root reconstruction, descending aortic aneurysm repair and abdominal aortic aneurysm repair. Patients with Marfan syndrome sometimes require repeated surgical repair of aortic disease.

Adult↗
PubMed2002

[Surgically treated pancoast tumor].

A 40-year-old male was detected his right apical lung tumor by roentgenographic screening on January 1997, but he did not refer to a hospital since he had no symptom. He went a orthopedics because of his right chest, back, and arm pain on October 1997, and he received traction and physical therapy. He went roentgenographic screening again on January 1998 and he was pointed out that the tumor increased. He admitted our hospital. Biopsy using bronchofiberscopy revealed adenocarcinoma and induction radiotherapy (40 Gy) was performed. Right upper lobectomy with chest wall resection and lymph node dissection was performed under hook approach. This approach was useful to dissect the tumor from the invaded plexus brachialis. Postoperative radio-chemotherapy was added but the patient died 7-postoperative months because of multiple metastases. Early detection should be led to early starting of the therapy.

Adult↗
PubMed2002

[Acute pulmonary thromboembolism complicating lung lobectomy; report of a case].

Acute pulmonary thromboembolism is fatal if the diagnosis and treatments are delayed. Here we present a case of acute thromboembolism to the right and left pulmonary arteries after right lung lobar resection. A 52-year-old woman who admitted to our hospital with lung cancer was performed right upper lobectomy with mediastinal lymph node dissection (pT1N0M0, well differentiated adenocarcinoma). Two days after surgery, she complained sudden chest discomfort and dyspnea. The blood pressure and oxygen saturation were rapidly decreased. Because there was no lung edema or atelectasis in the chest portable roentgenogram and no ischemic change in the electrocardiogram, pulmonary thromboembolism was suspected and emergency chest computed tomography (CT) was performed. The CT showed left and right pulmonary arterial thromboembolism and immediate anti-coagulator therapy was started. Her condition was improved and chest CT, which was performed three days after the onset of the thromboembolism, showed decreased but still remained thrombus. The anti-coagulator therapy was continued and one month after the onset of the thromboembolism, thrombus was disappeared on chest CT. She is doing well 17 months after surgery. Early diagnosis and treatments are critical for the pulmonary thromboembolism.

Adenocarcinoma↗
PubMed2001

Transcription factor expression and Notch-dependent regulation of neural progenitors in the adult rat spinal cord.

Recent studies have demonstrated that neural stem cells and other progenitors are present in the adult CNS. Details of their properties, however, remain poorly understood. Here we examined the properties and control mechanisms of neural progenitors in the adult rat spinal cord at the molecular level. Adult and embryonic progenitors commonly expressed various homeodomain-type (Pax6, Pax7, Nkx2.2, and Prox1) and basic helix-loop-helix (bHLH)-type (Ngn2, Mash1, NeuroD1, and Olig2) transcriptional regulatory factors in vitro. Unlike their embryonic counterparts, however, adult progenitors could not generate specific neurons that expressed markers appropriate for spinal motoneurons or interneurons, including Islet1, Lim1, Lim3, and HB9. Cells expressing the homeodomain factors Pax6, Pax7, and Nkx2.2 also emerged in vivo in response to injury and were distributed in unique patterns in the lesioned spinal cord. However, neither the expression of the neurogenic bHLH factors including Ngn2, Mash1, and NeuroD1 nor subsequent generation of new neurons could be detected in injured tissue. Our results suggest that signaling through the cell-surface receptor Notch is involved in this restriction. The expression of Notch1 in vivo was enhanced in response to injury. Furthermore, activation of Notch signaling in vitro inhibited differentiation of adult progenitors, whereas attenuation of Notch signals and forced expression of Ngn2 significantly enhanced neurogenesis. These results suggest that both the intrinsic properties of adult progenitors and local environmental signals, including Notch signaling, account for the limited regenerative potential of the adult spinal cord.

Animals↗
PubMed2001

Structural and sequence diversity of the pathogenicity island of uropathogenic Escherichia coli which encodes the USP protein.

A total of 321 uropathogenic Escherichia coli (UPEC) strains and 12 strains of E. coli isolated from stool samples of healthy individuals, which were previously shown to be positive in colony hybridization test using the usp (encoding for the uropathogenic-specific protein) DNA probe, were examined by PCR amplification to determine the size of the usp gene and the pathogenicity island (PI). Three types of size variation were observed for the usp gene and four types for the PI. Sequencing analysis of the PIs from seven representative strains (six UPEC and one from a normal healthy individual) revealed that the usp genes can be classified into two groups, each having different sequences in the 3'-terminal region. The peptides encoded by the three open reading frames (ORFs) downstream of usp had identical 23 amino acid residues in the C-terminal region. The subregion encoding these small ORFs has a mosaic structure constituted of six segments. The positions of these segments vary from strain to strain, and in some strains, two to four segments are deleted. This indicates that rearrangements occur frequently in this region and the mosaic arrangement apparently contributes to the size variation observed in the PCR examination of the usp genes and PIs.

Amino Acid Sequence↗
PubMed2001

Inhibition of angiogenesis by humulone, a bitter acid from beer hop.

On the basis of our previous finding that humulone, a bitter acid from beer hop extract, was a potent inhibitor of bone resorption and inhibited the catalytic activity of cyclooxygenase-2 (COX-2) and more potently the transcription of the COX-2 gene, we examined the effect of humulone on angiogenesis, using chick embryo chorioallantoic membranes (CAMs) and vascular endothelial and tumor cells. Humulone significantly prevented in vivo angiogenesis in CAM in a dose-dependent manner with an ED(50) of 1.5 microg/CAM. Humulone also inhibited in vitro tube formation of vascular endothelial cells. Moreover, it suppressed the proliferation of endothelial cells and the production of vascular endothelial growth factor (VEGF), an angiogenic growth factor, in endothelial and tumor cells. Thus, humulone is a potent angiogenic inhibitor, and may be a novel powerful tool for the therapy of various angiogenic diseases involving solid tumor growth and metastasis.

Allantois↗
PubMed2001

Total synthesis of (+/-)-stemodinone via an efficient ring-exchange strategy.

A total synthesis of (+/-)-stemodinone, a tetracyclic stemodane diterpene, from the known tricyclic methyl olefin 11 is described. The key steps involve an efficient ring-exchange reaction and palladium(0)-catalyzed lactone migration. The ring-exchange strategy for controlling the stereochemistry was based on an initial Diels-Alder reaction to form a new ring followed by cleavage of the original ring. Cleavage of the original ring of the Diels-Alder adduct 9 was achieved by an initial regio- and chemoselective Baeyer-Villiger oxidation followed by the Pd(0)-catalyzed lactone-migration reaction reported by us.

Antiviral Agents↗