Biomedical subjects

Jun Kawamoto

Publications and source records attributed to Jun Kawamoto.

7 recordsLinked to original sources

PubMed2025

Rapid screening and identification of genes involved in bacterial extracellular membrane vesicle production using a curvature-sensing peptide.

Bacteria secrete extracellular membrane vesicles (EMVs). Physiological functions and biotechnological applications of these lipid nanoparticles have been attracting significant attention. However, the details of the molecular basis of EMV biogenesis have not yet been fully elucidated. In our previous work, an N-terminus-substituted FAAV peptide labeled with nitrobenzoxadiazole (NBD; nFAAV5-NBD) was developed. This peptide can sense the curvature of a lipid bilayer and selectively bind to EMVs even in the presence of cells. Here, we applied nFAAV5-NBD to a genome-wide screening of hyper- and hypo-vesiculation transposon mutants of a Gram-negative bacterium, Shewanella vesiculosa HM13, to identify the genes involved in EMV production. We analyzed the transposon insertion sites in hyper- and hypo-vesiculation mutants and identified 16 and six genes, respectively, with a transposon inserted within or near them. Targeted gene-disrupted mutants of the identified genes showed that the lack of putative dipeptidyl carboxypeptidase, glutamate synthase β-subunit, LapG protease, metallohydrolase, RNA polymerase sigma-54 factor, inactive transglutaminase, PepSY domain-containing protein, and Rhs-family protein caused EMV overproduction. On the other hand, disruption of the genes encoding putative phosphoenolpyruvate synthase, d-hexose-6-phosphate epimerase, NAD-specific glutamate dehydrogenase, and sensory box histidine kinase/response regulator decreased EMV production. This study demonstrates the utility of a novel screening method using a curvature-sensing peptide for mutants with altered EMV productivity and provides information on the genes related to EMV production.IMPORTANCEConventional methods for isolation and quantification of extracellular membrane vesicles (EMVs) are generally time-consuming. nFAAV5-NBD can detect EMVs in the culture without separating EMVs from cells. In situ detection of EMVs using this peptide facilitated screening of the genes related to EMV production. We succeeded in identifying various genes associated with EMV production of Shewanella vesiculosa HM13, which would contribute to the elucidation of bacterial EMV formation mechanisms. Additionally, the hyper-vesiculating mutants obtained in this study would be valuable for EMV applications, such as secreting useful substances as EMV cargoes and producing artificially functionalized EMVs.

Shewanella↗

PubMed2006

[Successful treatment for intractable ascites with uterine cancer using double Denver peritoneovenous shunt system].

A 59-year-old woman, who underwent uterectomy for uterine cancer in February 2000, was diagnosed having carcinomatous peritonitis with intractable ascites due to recurrent uterine cancer in November 2004. We conducted a peritoneovenous shunting at the right side of the abdominal cavity using the Denver peritoneovenous shunt system. A significant reduction in body weight and abdominal girth was seen during the follow up period. After 2 months, the intractable ascites was aggrayating. Because of the partition of the abdominal cavity by the greater omentum, the intractable ascites was dominant in the left side of the abdominal cavity compared with the right side. So we tried additional moreperitoneovenous shunting at the left side of the abdominal cavity using the Denver peritoneovenous shunt system. Finally, ascites and body weight were decreased. She was discharged from our hospital with a good quality of life. Double peritoneovenous shunt (Denver peritoneovenous shunt system) is a useful palliative treatment for intractable such as this case. Further experience and discussion are necessary to indicate this procedure.

Ascites↗

PubMed2005

Evaluation of platelet indexes in patients with aortic aneurysm.

The purpose of this study was to investigate whether platelet indexes [platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR), and platelet distribution width (PDW)] could serve as diagnostic tools to evaluate the potential significance of platelet heterogeneity on thrombus formation. Blood samples were obtained from 54 patients with aortic aneurysm (AA; mean age 73 years; 40 males, 14 females), from 120 age-matched controls (AC; mean age 74 years; 61 males, 59 females), and from 38 young controls (YC; mean age 30 years; 20 males, 18 females). We measured the blood platelet indexes using an automated counter, as well as plasma D-dimer and thrombin-antithrombin III complex (TAT) using ELISA. The AA patients were divided into two groups, group A (platelet count more than 150 x 10(9)/l, n = 36) and group B (platelet count below 150 x 10(9)/l, n = 18). There was no difference in the platelet count between AC and YC. However, P-LCR was significantly higher (p = 0.0113) in AC. MPV and PDW were also higher, but not significantly so. The platelet count was not different between group A and AC. MPV (p = 0.0024 and <0.0001, respectively), P-LCR (p < 0.0012 and <0.0001, respectively) and PDW (p = 0.0006 and 0.0005, respectively) were significantly lower in group A than in group B and AC. The platelet indexes were significantly lower in the 54 AA patients than in the AC. There were significant inverse relationships between the platelet count and other indexes in the AC and 54 AA patients; however, no relationships were observed in group A, B and YC. The D-dimer and TAT levels were significantly higher in group B than in groups A and YC. In conclusion, these findings suggest that large platelets decrease rather than increase in patients with AA.

Adolescent↗

PubMed2005

[Portal vein stenting for portal hypertension caused by local recurrence following hepato-pancreatoduodenectomy for bile duct cancer].

The patient was a 73-year-old man diagnosed with bile duct cancer. He underwent hepato-pancreatoduodenectomy and a combined resection of portal vein in July 2002. The post operative course was uneventful. In December 2003 he had a loss of consciousness, and was admitted to our hospital as an emergency patient. Abdominal CT scan and angiography revealed the presence of portal vein stenosis due to local recurrence of bile duct cancer resulting in portal hypertension. Thus, a metallic stent was placed in the portal vein to maintain portal blood flow. A non-covered metallic stent, 10 mm in diameter and 80 mm in length (SMART stent, Cordis Endovascular), was deployed through the stenotic portal vein. Portography after the stent placement showed a relief of the portal vein stenosis. Intravenous heparin administration was performed at a dose of 5,000 IU per day for 5 days after the stent placement, and this was followed by oral warfarin potassium administration. The clinical course was uneventful and the patient was discharged 21 days after portal stent placement. Portal stenting successfully improved portal hypertension due to stenosis of the portal vein without any complication. Our experience suggests that the portal vein stenting using the SMART stent is useful palliative therapy for portal vein stenosis.

Aged↗

PubMed2002

Aortic root replacements in reoperations.

We evaluated 4 patients who had undergone previous cardiac surgery underwent reoperation involving aortic root replacement. Subjects were a 55-year-old man who had undergone separate valve graft replacement for a dissecting aneurysm (DeBakey type I) 3.25 years earlier; a 51-year-old woman who had undergone separate valve graft replacement for a dissecting aneurysm (DeBakey type I) 6 years earlier; a 66-year-old woman who had undergone aortic valve replacement and single coronary artery bypass grafting for severe aortic regurgitation, angina pectoris, and aortitis syndrome 11 years earlier; a 47-year-old man who had undergone mitral valve replacement and 3-coronary artery bypass grafting for severe mitral regurgitation and angina pectoris 4 years earlier. Development of a surgical technique, coupled with myocardial protection, and pharmacological treatment at reoperation yielded excellent early surgical results. To reduce the incidence of reoperation and ensure satisfactory long-term results, we recommend radical management for the individual case be selected at initial operation and entire resections be conducted for aneurysmal degeneration or dissected segments.

Aged↗

PubMed2002

Minimally invasive direct redo coronary artery bypass grafting.

Redo coronary artery bypass grafting due to graft failure and the progression of new lesions has been increasing in frequency recently. We are often forced to revascularize only the left anterior descending artery (LAD) in very elderly patients with a high risk to median sternotomy. We performed reoperative minimally invasive direct coronary artery bypass grafting (MIDCABG) in seven patients. The target sites were as follows: LAD, 7; first diagonal branch, 1; and the graft material was the left internal thoracic artery (LITA), 7; and saphenous vein graft (SVG), 1. Complete revascularization was accomplished in all patients, by including hybrid therapy in three patients and axillo-coronary bypass grafting with SVGs in two patients. Postoperative angiography showed all patent grafts and all patients were discharged. During a mean follow-up period of 2.4 years (range: 0.5 to 3.5 years), all were free from cardiac events, except for one patient who had recurrent angina due to failure of a previously patent graft 3 years after redo MIDCAB. These results suggest that MIDCABG via left antero-lateral thoracotomy is an effective and safe technique in redo cases, as well as an alternative procedure for hybrid revascularization that combines minimally invasive revascularization of LAD with additional catheter interventional therapy.

Aged↗

PubMedDate not supplied

Relationship between hemostatic markers and circulating biochemical markers of collagen metabolism in patients with aortic aneurysm.

Our objective was to determine the relationship between plasma levels of hemostatic molecular markers--D-dimer and thrombin-antithrombin III complex (TAT)--and circulating biochemical markers of collagen metabolism--aminoterminal propeptide of type III procollagen (PIIIP) and carboxyterminal propeptide of type I procollagen (PICP)--in patients with aortic aneurysm. The subjects were 43 patients with aortic aneurysm (AA; mean age 71 years) and 26 age-matched controls (mean age 75 years). The mean D-dimer, TAT and PIIIP levels were higher in the patients than in the controls (p < 0.0001, 0.0001 and 0.012, respectively), while the mean PICP level was similar to that in the controls. Increased D-dimer had a significant correlation with PIIIP (r = 0.412, p = 0.006) and PICP (r = 0.342, p = 0.0246), while TAT correlated with PIIIP (r = 0.3194, p = 0.0374), but not with PICP. There was also a significant correlation (r = 0.306, p = 0.0463) between PIIIP and PICP. As shown by the significant positive correlations among D-dimer, TAT and PIIIP, accelerated fibrinolysis and thrombogenesis induce an increase of collagen degradation and procollagen synthesis in atherosclerotic lesions. These findings show that D-dimer and TAT, especially the former, may be useful markers to monitor the progression and predict the prognosis of AA.

Aged↗