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Biomedical subjects

K Imanaka

Publications and source records attributed to K Imanaka.

At least 19 recordsLinked to original sources
PubMed2006

A new method of diagnosing gastric intestinal metaplasia: narrow-band imaging with magnifying endoscopy.

BACKGROUND AND STUDY AIMS: With endoscopy, there is a high rate of interobserver variability in the identification of gastric intestinal metaplasia, and the endoscopic findings correlate poorly with the histological findings. Previous studies by our group investigating the use of a narrow-band imaging system with magnifying endoscopy (NBI-ME) in the gastric mucosa suggested that the appearance of a light blue crest (LBC) on the epithelial surface may be a distinctive endoscopic finding associated with the presence of intestinal metaplasia. The aim of the present study was to clarify the value of NBI-ME for diagnosing gastric intestinal metaplasia. PATIENTS AND METHODS: The LBC was defined as a fine, blue-white line on the crests of the epithelial surface/gyri. To investigate the histology underlying the appearance of LBC, 44 biopsy specimens were obtained from regions containing LBC and 44 from non-LBC mucosa in 34 patients with atrophic gastritis. Three endoscopists then carried out NBI-ME in 107 consecutive patients to validate the diagnostic accuracy of the novel endoscopic technique. The degree of correlation between the LBC grading and the histological parameters of intestinal metaplasia was then assessed. RESULTS: The LBC grading correlated with cells that were positive for CD10 ( P = 0.0001) and Alcian blue ( P = 0.036). The appearance of LBC correlated with histological evidence of intestinal metaplasia with a sensitivity of 89 % (95 % CI, 83 - 96 %), a specificity of 93 % (95 % CI, 88 - 97 %), a positive predictive value of 91 % (95 % CI, 85 - 96 %), a negative predictive value of 92 % (95 % CI, 87 - 97 %), and an accuracy of 91 % (95 % CI, 88 - 95 %). CONCLUSIONS: In narrow-band imaging with magnifying endoscopy, observation of a light blue crest on the epithelial surface in the gastric mucosa is a highly accurate sign of the presence of histological intestinal metaplasia.

Adult↗
PubMed2005

Hemodynamic infarction of the spinal cord: involvement of the gray matter plus the border-zone between the central and peripheral arteries.

OBJECTIVE: Hemodynamic infarction of the spinal cord that affected an 81-year-old female having a dissecting aortic aneurysm is presented. During the graft replacement operation, systemic hypotension occurred and the patient was subsequently complicated with paraplegia of the lower limbs. The patient died 2 weeks after the surgery due to gastrointestinal bleeding. An autopsy, which did not include the brain, was performed and the spinal cord was sampled. The aim of this report is to describe the pathologic profile of the spinal cord of the patient, and to gain insight into the pathogenesis of the lesion. METHODS: Histochemical and immunohistochemical methods were employed to study the spinal cord ranging from the lower thoracic to sacral segments. RESULTS: The whole central areas of the spinal cord showed coagulation and/or liquefaction necroses, while the white matter on the circumference of the cord remained unaffected, thus exhibiting a 'ring-like' appearance. CONCLUSION: This case is an example of hemodynamic infarction of the spinal cord involving the gray matter that is supplied by the central artery, plus the border-zone that is supplied by both the central and peripheral arteries. The former is probably associated with selective vulnerability of the gray matter to ischemia, while the latter is probably associated with intrinsic vulnerability of the border-zone to systemic hypotension or low blood-flow states.

Aged↗
PubMed2005

Enhanced expression of suppressor of cytokine signalling-1 in the liver of chronic hepatitis C: possible involvement in resistance to interferon therapy.

Interferon-alpha (IFN-alpha) is widely used in the treatment of chronic hepatitis C (CHC). The suppressor of cytokine signalling (SOCS) family has been implicated in the regulation of JAK-STAT signalling, including IFN signalling. The negative effect of SOCS expression on the response of CHC to IFN-alpha is demonstrated here. The transcriptional levels of SOCS-1 and -3 in the livers of 21 patients with CHC and eight controls were investigated by quantitative reverse transcription-polymerase chain reaction. We established stable transfectants of SOCS-1 in a human hepatoma cell line, PLC/PRF/5 and analysed the effects of SOCS-1 on the phosphorylation of IFN-alpha-induced STAT-1 tyrosine by immunoblotting and the expression of antiviral genes by Northern blot. A prospective cohort study on SOCS-1 expression and clinical outcome was carried out in 77 patients with CHC who received IFN therapy. SOCS-1, but not SOCS-3, transcripts in the livers of CHC were significantly higher than controls (P < 0.005). IFN-alpha-induced STAT-1 phosphorylation and the expression of antiviral genes were inhibited in SOCS-1-transfected cells. Patients showing high SOCS-1 expression in the liver had a significantly lower rate of sustained virological response (SVR) to IFN therapy than those with low SOCS-1 expression (P = 0.0014). A multivariate analysis performed with host factors revealed that SOCS-1 staining in the liver can serve as a significant predictor for IFN SVR (P = 0.004). SOCS-1 expression is enhanced in the livers of CHC patients and might be involved in resistance to IFN therapy.

Adult↗
PubMed2005

[Aortic root remodeling and coronary artery bypass grafting for acute type A aortic dissection involving the left main coronary artery; report of a case].

A 56-year-old male was admitted for sudden chest pain followed by loss of consciousness and paraplegia. The electrocardiogram (ECG) revealed ST-elevation in leads II, III, and aVF and ST-depression in leads V3 to V6. The ultrasonic cardiography (UCG) demonstrated an intimal flap in the ascending aorta, grade III aortic regurgitation (AR), and akinesis of the posterior wall of the left ventricle. Transesophageal echocardiography directly showed dissection of the left main coronary artery. Emergency coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD), obtuse marginal artery (OM) and posterolateral artery (PL) was performed using the saphenous vein. In addition, valve-sparing aortic root remodeling was performed in conjunction with replacement of the ascending aorta. The left coronary orifice was repaired and reattached to the prosthetic graft. The patient was weaned from cardiopulmonary bypass without catecholamine support. He was discharged from the hospital on foot after rehabilitation of the paraplegia. AR remains mild by UCG 3 years after surgery.

Acute Disease↗
PubMed2004

[Long survival with chronic ventricular fibrillation under support of uni-left-ventricular assist system].

Few minutes of suspended malignant ventricular arrhythmia may be permitted for the patient with left ventricular assist system (LVAS). However, longer and continuous ventricular arrhythmia, especially ventricular fibrillation (Vf), may induce the low output of LVAS, which leads circulatory collapse immediately. Our presenting case is a female dilated cardiomyopathy patient who has been supported with LVAS. Four months after the LVAS installation, her electrocardiogram has changed to Vf without any symptoms. Her ventricular function has never recovered, even ventricular tachycardia. She has been a candidate of heart transplantation for more than 19 months with this rare hemodynamic condition (LVAS+Vf), like the Fontan circulation. Her performance status is limited due to deceasing of the LVAS flow, which caused by the change of her position: 2.5-2.9 l/min (lie down) to 2.0 l/min (rise). Her peak VO2/W is 6.9 ml/min/kg measured by the cardio-pulmonary exercise test. However, she has developed her general status by doing rehabilitation program and is able to walk for more than 100-150 meters.

Adult↗
PubMed2004

[Infective endocarditis caused by methicillin resistant Staphylococcus aureus following corticosteroid pulse therapy; report of a case].

A 51-year-old man, with a history of corticosteroid pulse therapy 3 weeks previously, developed infective endocarditis of the mitral valve due to methicillin resistant Staphylococcus aureus, and underwent mitral valve replacement. Since the second postoperative day, clinical course was seriously complicated because of recurrent abdominal pain corresponding with commencement of oral intake, unremitting spike fever, and renal and hepatic dysfunction. Various examinations except angiography failed to demonstrate the etiology. Two months later, the patient developed panperitonitis due to perforation of ischemic ulcer of the cecum and underwent ileo-cecal resection. After this operation, he convalesced very quickly. Ischemia is one of the main causes of abdominal complication following cardiac surgery. Angiography should be positively considered in cases like the present one.

Abdominal Pain↗
PubMed2003

[Coronary artery aneurysm developed acute myocardial infarction: report of a case].

A 68-year-old woman without angina developed acute antero-septal myocardial infarction. Coronary angiogram revealed saccular coronary artery aneurysm at the origin of the diagonal branch and relatively mild coronary artery stenosis. Emboli from the coronary aneurysm was strongly suggested. We placed coronary bypass grafts onto left anterior descending, diagonal and obtuse marginal branches, and excluded the coronary aneurysm by ligating both its inflow and outflow. The postoperative course was uneventful. There are several treatments of choice for patients with coronary aneurysm. We believe that surgery is mandatory and that exclusion of the coronary aneurysm should be considered in every possible case.

Aged↗
PubMed2003

[Resection of freely mobile atheroma in the ascending aorta under circulatory arrest during coronary artery bypass grafting surgery].

A 52-year-old male with a 13 years history of hemodialysis developed unstable angina. Preoperative examination revealed critical stenoses in 3 coronary arteries and extensive calcification in the ascending aorta. During urgent coronary artery bypass surgery, epiaortic ultrasonography demonstrated a large and markedly mobile atheroma in the ascending aorta. Therefore, he underwent resection of this atheroma using cardiopulmonary bypass and circulatory arrest. His postoperative course was fine. This aggressive strategy for a diseased aorta can be a viable option in selected cases. Epiaortic ultrasonography appeared to be indispensable during surgery for patients like a present one.

Aorta↗
PubMed2001

Covered Gianturco stent for tracheal stricture: application of polychlorovinylidene and polyurethane as covering materials.

The aim of this study was to assess the efficacy and safety of thin membranes of polychlorovinylidene (PCV) or polyurethane (PU) as covering materials for Gianturco stents in the treatment of severe tracheal stricture caused by intraluminal tumor. Manufactured Gianturco stents covered with PCV or PU membrane were used to treat six malignant and one benign tracheal stricture. The initial results, complications, clinical follow-up, bronchoscopic findings, and three autopsy microscopic examinations were reviewed. Informed consent was obtained after the nature of the treatment had been fully explained before every procedure. The stents successfully dilated the tracheal strictures, providing immediate relief of respiratory symptoms in all patients with no major complications. During the follow-up period, the covering materials prevented tumor ingrowth until death or intraluminal granuloma formation. Autopsies proved that no histological change occurs in the tracheal mucosa in response to the presence of PCV or PU; however, ulcer formation occurred in one patient and penetration of the stent struts into the tracheal wall in two. Bloody sputum with ulcer formation, minimal granuloma formation at the distal end of the stent, and abnormal bacterial load in the sputum were long-term complications. The Gianturco stent covered with PCV or PU membrane is a useful option as a palliative treatment for malignant and an emergent salvage for benign tracheal stricture, because both materials are thinner and less voluminous than the others. However, the indications for its use are limited to patients with poor prognoses, because hemoptysis, granuloma formation, and bacterial propagation remain problematic.

Aged↗
PubMed2001

Patterns of muscle activation in human hopping.

In the present study, we examined the electromyogram (EMG) patterns of the soleus and medial gastrocnemius (MG) muscles during rhythmical, two-legged hopping to investigate the contributions of the monosynaptic short- and long-latency stretch reflexes during such a natural movement in human. During rhythmical hopping, soleus muscle is activated reflexly at near-monosynaptic latency by stretch resulting from passive ankle flexion upon landing. Soleus muscle also contracts voluntarily in order to launch the body into the next hop. This is part of the rhythmical bursts of activity producing the hops. Depending on the hopping interval, this phase of activation can follow the short-latency phase or precede landing at very short hopping intervals. In MG, there is an initial phase of activity that stiffens the muscle in preparation for landing, and continues through the contact phase. The monosynaptic reflex response to landing is usually superimposed on this activity. Depending on the hopping interval, both of these responses may be overlaid with activity that is time-locked to the take-off into the next hop, and serves to launch the body into the next hop. However, no evidence for a long-latency stretch reflex was found. In addition, the preferred hopping frequency for all subjects was about 2 Hz. This frequency is associated with a pattern of EMG activity the timing of which indicates that it balances the requirement for a comfortable landing from a hop with the optimal muscle activation required for launching the following hop.

Adult↗
PubMed2001

L-Arginine given after ischaemic preconditioning can enhance cardioprotection in isolated rat hearts.

OBJECTIVE: Ischaemic or pharmacological preconditioning with L-arginine has been reported to be insufficient for optimal cardioprotection. The ability of nitric oxide (NO) to enhance ischaemic preconditioning was assessed, and the role of L-arginine-induced ischaemic preconditioning in myocardial protection was determined. METHODS: Isolated rat hearts were prepared and divided into six groups: control hearts (control, n=6) were perfused without global ischaemia at 37 degrees C for 160 min; global ischaemia hearts (GI, n=6) were subjected to ischaemia for 20 min and reperfusion for 120 min; ischaemic preconditioned hearts (IP, n=6) received 2 min of zero-flow global ischaemia followed by 5 min reperfusion, before 20 min of global ischaemia; L-arginine hearts (ARG, n=6) received 1 mmol/l L-arginine for 5 min, before 20 min of global ischaemia; ischaemic preconditioning plus nitro-L-arginine methyl ester hearts (IP+L-NAME, n=6) received 2 min of ischaemic preconditioning and 5 min reperfusion with 3 mmol/l L-NAME in Krebs-Henseleit buffer, before 20 min of global ischaemia; and ischaemic preconditioning plus L-arginine hearts (IP+ARG, n=6) received 2 min of ischaemic preconditioning and 5 min reperfusion with 1 mmol/l L-arginine in Krebs-Henseleit buffer. Haemodynamic parameters and coronary flow were recorded continuously. Nitrites and nitrates (NOx) were measured 5 and 60 min after reperfusion, and infarct size was also determined. RESULTS: In the IP+ARG group, significant amelioration and preservation of left ventricular peak developed pressure and coronary flow was observed compared with the GI, IP, ARG and IP+L-NAME groups. Infarct size in the IP+ARG group was reduced significantly compared with that in the GI, IP, ARG and IP+L-NAME groups. Significant preservation of NOx was observed during reperfusion in the IP+ARG group compared with the GI group. CONCLUSIONS: Inhibition of NO synthase with L-NAME had little impact on ischaemic preconditioning, suggesting that endogenous NO is not a major mediator of ischaemic preconditioning. Nevertheless, enhancement of the effects of ischaemic preconditioning can be achieved with L-arginine, a precursor of NO, improving post-ischaemic functional recovery and infarct size in the isolated rat heart.

Animals↗
PubMed2001

Favorable results in patients with small size CarboMedics heart valves in the aortic position.

Hemodynamic performance of the CarboMedics heart valve in the aortic position and its clinical impacts were investigated in 126 consecutive patients. The actuarial survival rates of patients who had undergone isolated aortic valve replacement and concomitant aortic and mitral valve replacement were 82.6+/-5.7% and 71.0+/-9.2% at 8 years, respectively. Morbid events were rare, and almost all late survivors were free from evident cardiac symptoms regardless of the valve size. Echocardiography revealed suboptimal transvalvular pressure gradients and effective orifice areas of 19 mm and 21 mm valves. However, relief of the left ventricular overload and improvement of the clinical symptoms as well as cardiac function were comparable to those of patients with larger valves. Valve function measured by echocardiography did not show significant correlation to late outcome. Good results can be expected even in the presence of echocardiographic data such as peak pressure gradient over 40 mmHg, effective orifice area less than 1.0 cm(2), and effective orifice area index less than 0.7 cm(2)/m(2).

Adolescent↗
PubMed2001

Effects of recombinant human erythropoietin therapy on blood coagulation and fibrinolysis system.

This study was designed to examine the effects of recombinant human erythropoietin (rHuEPO) therapy on blood coagulation and fibrinolysis in patients scheduled for elective heart surgery and undergoing preoperative autologous blood donation. Twenty-seven patients were studied, of whom 16 patients received rHuEPO (group E) and 11 patients no rHuEPO therapy (group N). The patients in group E were given 6000 units of rHuEPO intravenously every other day, three times a week, beginning from two weeks prior to the operation. In both groups, 400 ml of blood was collected preoperatively for predeposit once a week for two weeks, and the self-donated blood was returned to the patient intra- and postoperatively. Blood samples were drawn at the beginning of the study, immediately before the operation and two weeks after the operation. They were analyzed to assess blood coagulation, fibrinolysis, platelet function and vascular endothelial cell function, in order to examine the effects of the administration of rHuEPO. No significant difference was observed between the two groups in the degree of changes in these parameters following the operation. As enhancement of blood coagulability and fibrinolytic activity was evident postoperatively in both groups, changes in these parameters during the preoperative autologous blood donation period were also assessed excluding the postoperative data. Again, there was no significant intergroup difference in any of the markers evaluated. It was concluded that the administration of rHuEPO during preoperative autologous blood donation is unlikely to affect coagulation and fibrinolysis.

Adult↗
PubMed2000

Easy aortic cannulation: a transxyphoid approach.

An easy aortic cannulation technique in minimally invasive pediatric cardiac surgery is described. We have developed a dilator which fits an aortic perfusion cannula. The aortic cannula over the dilator with a hole for passage of a guide wire is inserted into the ascending aorta by the Seldinger technique. Using this technique, the cannula never slips off, even at a slant angle to the aorta owing to the guidance of the guide wire. We recommend this safe and reliable technique for insertion of an aortic cannula into the ascending aorta in minimally invasive pediatric cardiac surgery.

Aorta↗