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Biomedical subjects

M Yamagishi

Publications and source records attributed to M Yamagishi.

At least 19 recordsLinked to original sources
PubMed2006

A novel method for measuring human hepatic lipase activity in postheparin plasma.

The objective of this study was to establish a hepatic lipase (HL) assay method that can be applied to automatic clinical analyzers. Seventy-four hyperlipidemic subjects (men/women 45/29) were recruited. Lipase activity was assayed measuring the increase in absorbance at 546 nm due to quinonediimine dye production. Reaction mixture R-1 contained 50 mM Tris-HCl (pH 9.5), 0.5 mM glycerol-1,2-dioleate, 0.4% (unless otherwise noted) polyoxyethylene-nonylphenylether, 3 mM ATP, 3 mM MgCl(2), 1.5 mM CaCl(2), monoacylglycerol-specific lipase, glycerol kinase, glycerol-3-phosphate oxidase, 0.075% N,N-bis-(4-sulfobutyl)-3-methylaniline-2 Na, peroxidase, ascorbic acid oxidase. Reaction mixture R-2 contained 50 mM Tris-HCl (pH9.5), 0.15% 4-aminoantypirine. Automated assay for activity was performed with a Model 7080 Hitachi analyzer. In the lipase assay, 160 microl of R-1 was incubated at 37 degrees C with 3 microl of samples for 5 min, and 80 microl of R-2 was added. Within-run coefficient of variations was 0.9-1.0%. Calibration curve of lipase activity was linear (r = 0.999) between 0 and 320 U/l. Analytical recoveries of purified HL added to plasma were 96.6-99.8%. HL activity in postheparin plasma measured in this method had a closer correlation with HL mass by a sandwich ELISA (r = 0.888, P < 0.0001) than those in the conventional method using [(14)C-]triolein (r = 0.730, P < 0.0001). This assay method for HL activity can be applied to an automatic clinical analyzer.

Adult↗
PubMed2005

Lack of chemopreventive effects of alpha-eleostearic acid on 7,12-dimethylbenz[a]anthracene (DMBA) and 1,2-dimethylhydrazine (DMH)-induced mammary and colon carcinogenesis in female Sprague-Dawley rats.

alpha-Eleostearic acid is one of the conjugated linolenic acids from tung oil, which is obtained from the seeds of Aleurites fordii. The effects of dietary alpha-eleostearic acid (18:3, n-5) on the post-initiation period of 7,12-dimethylbenz[a]anthracene (DMBA) and 1,2-dimethylhydrazine (DMH)-induced mammary and colon carcinogenesis were examined using female Sprague-Dawley (SD) rats. For initiation, rats were given subcutaneous injections of 40mg/kg body weight (5 times) and 20mg/kg body weight (3 times) of DMH during the age of 6-8 weeks and a single intragastric administration of 50mg/kg body weight of DMBA at 9 weeks. Then, the animals were treated with 0%, 0.01%, 0.1% or 1.0% alpha-eleostearic acid for 34 weeks. Control rats received the basal diet alone or 1.0% alpha-eleostearic acid without prior initiation treatment. All surviving animals were killed at week 37 of the experiment. There were no statistically significant alterations in any of the parameters for either mammary or colon tumors. These results thus indicate that alpha-eleostearic acid does not exert clear modification effects on DMBA and DMH-induced mammary and colon carcinogenesis, at least under the present experimental conditions.

1,2-Dimethylhydrazine↗
PubMed2005

Commentary on the prevention of paralysis after traumatic spinal cord injury in humans: the neglected factor--urgent restoration of spinal cord circulation.

Although advances in the management of spinal injuries during the past 60 years have led to greatly increased life expectancy for paralysed patients, most remain disabled. Around the world, spinal injury centres have become specialized rehabilitation units, where staff accepts the inevitability of persisting paralysis. In part, this pessimism has been based on incorrect information about the anatomy and function of the circulation of the spinal cord. Since the publication of accurate descriptions of the segmental nature of spinal vasculature, research and clinical data suggest that reversal or prevention of paralysis after spinal injury may be possible in many patients. These improved outcomes will depend on the recognition that urgent correction of cord blood supply in patients with traumatic spinal injury is critical to the long-term results of treatment. The creation of specialist spinal units within trauma centres for the urgent treatment of patients following spinal injury will require considerable logistical change, but has the potential to lead to a revolution in spinal care, driven by the knowledge that spinal cord function can often be saved.

Adult↗
PubMed2005

Synthesis of nanoporous graphite-derived carbon-silica composites by a mechanochemical intercalation approach.

A mechanochemical intercalation approach which applies a simple mechanical milling to induce intercalation reaction was applied to introduce controlled amount of tetraethoxylsilane (TEOS) into surfactant-preexpanded graphite oxide, and the relationships between the intercalation structure, the porosities of the calcined products, and the Si addition were examined. It was found that a small added amount of TEOS produced a more expanded ordered layer structure with the interlayer distance and silicon content increasing with the amount of TEOS added, although a large amount of added TEOS easily induces layer delamination, resulting in a less ordered structure. The silica structure in the composite is changed from a disordered structure having enhanced bond strain to a condensed silica network when the amount of TEOS added increases. The porosities of the final calcined samples increase with the increase of silicon content but then decrease slightly after reaching a maximum where silicon content starts to become constant, indicating that both silicon content and the composition state of silica particles and carbon layers play important roles in porosity formation.

Journal Article↗
PubMed2005

[Surgically resected lung cancer in patients complicated with diffuse interstitial pulmonary shadow].

In 25 patients operated on for idiopathic interstitial pneumonia (IIP) associated with primary lung cancer, we clinically examined the predictive factors related to the acute exacerbation of IIP preoperatively and during operation. Most were male heavy smokers. Ages ranged 57 to 78 years. Standard surgery was performed in 11 patients, extended resection in 4 patients and limited resection in 10 patients. The incidence of postoperative acute exacerbation of IIP was 40% (10 patients). These patients were treated with steroid pulse therapy, 3 patients died due to acute exacerbation but 7 patients recovered. It seemed difficult to anticipate postoperative exacerbation of IIP based on preoperative patients evaluation and the degree of surgical invasiveness. Seven patients were alleviated with erythromycin before and after the operation and 4 patients were alleviated with high-dose steroid during or after surgery, with these patients not developing exacerbation of IIP. From these results, it was suggested that high-dose steroid administration during or after surgery and erythromycin before and after the operation were effective to avoid postoperative exacerbation of IIP.

Aged↗
PubMed2004

Mechanism of improvement in exercise capacity after the maze procedure combined with mitral valve surgery.

OBJECTIVE: To clarify the mechanism of improvement in exercise capacity after the maze procedure. DESIGN: Retrospective study. SETTING: Tertiary referral centre. PATIENTS: 26 patients (mean (SD) age 57 (9) years) with atrial fibrillation (AF) and mitral valve disease were studied with echocardiography and cardiopulmonary exercise testing before and after the maze procedure combined with mitral valve surgery. Of these, eight had persistent AF and 18 had restored sinus rhythm (SR) by the surgery. Six patients (mean (SD) age 59 (12) years) with AF undergoing mitral valve surgery without the maze procedure who had cardiopulmonary exercise testing before and after the surgery formed the control group. MAIN OUTCOME MEASURES: Echocardiographic parameters of atrial function were measured from transmitral flow recordings. Peak oxygen uptake (VO2) and the slope of the relation between VO2 and workload (ratio of DeltaVO2 to Delta work) were determined as indices of exercise capacity. RESULTS: The degree of improvements in peak VO2 and the ratio of DeltaVO2 to Delta work after the mitral valve surgery was comparable between the maze and control group. It was also comparable between patients with and those without successfully restored SR after the maze procedure. The degree of the increase in peak VO2 correlated with the change in left atrial diameter (r = -0.40, p = 0.047) but atrial contraction did not correlate with the increase. CONCLUSIONS: Improvement in exercise capacity may not be caused by restored SR and atrial contraction but may at least partly relate to the reduction of left atrial size and improvement of haemodynamic variables by the surgery.

Adult↗
PubMed2004

[Solitary hemangioma of the rib; report of a case].

A case of solitary hemangioma which occurred in the rib. Tumor located in the right seventh rib, incidentally taken X-ray film demonstrated bone tumor, but she had no symptoms. Four years after, chest pain occurred and taken X-ray film, tumor size was inceeced. Computed tomography (CT) showed an expansile, well demarcated lesion, with thin corices and fine trabeclae. Chest wall, from the sixth rib to the eighth rib resection was performed and surgical margin was 4 cm. This case were diagnosed hemangioma of the rib. Hemangiomas of the bone are rare benign vascular tumors that account for less than 1% of all bony neoplasms. These lesions are most often occurring in the vertebral column or in the skull. The localization to the ribs is even more rare, with only sporadic case reports in the literature.

Aged↗
PubMed2003

Mitral valve injury during balloon valvuloplasty for an infant with severe aortic stenosis: spatial evaluation using three-dimensional echocardiography.

We report on a 4-month-old infant with mitral valve injury that was induced by percutaneous balloon valvuloplasty for severe aortic valve stenosis. Three-dimensional echocardiography revealed a laceration at the anterior leaflet of the mitral valve. The mitral valve injury was successfully repaired by surgical operation 1 year after the valvuloplasty. This unexpected complication is associated with anatomical disorders of congenital aortic stenosis, including hypoplastic left ventricle, short chordae tendae, and large papillary muscles.

Aortic Valve Stenosis↗
PubMed2003

Vertebral arch reconstruction based on 90 degree rotational laminoplasty after removal of spinal cord and cauda equina tumours.

BACKGROUND: A variety of procedures for reconstructing the spine following the removal of spinal cord and cauda equina tumours have been developed to prevent postoperative spinal deformities and nerve entrapment. The purpose of this paper is to introduce a new reconstructive procedure based on rotational laminoplasty and to report preliminary results in a small series. METHOD: The trough is drilled at the border of the laminae and articular processes and the ligamentum flavum is resected on its cephalocaudal aspect, so the vertebral arch can be separated as a single mass. After tumour resection, the vertebral arch is removed en bloc with the laminae, and is rotated 90 degrees and placed on the articular facets and fixed using suture passing through holes drilled in the bone. FINDINGS: One man and six women underwent rotational laminoplasty following resection of spinal or cauda equina tumours. Operative exposure was good and permitted complete resection. Patients did well postoperatively from both spine-surgical and neurosurgical points of view. Computed tomography documented a bony union with preservation of widely patent spinal canal. INTERPRETATION: Rotational laminoplasty affords a satisfactory operative exposure for the resection of large, complex lesions. It creates a widely patent, stable spinal canal easily, without the need for special tools.

Aged↗
PubMed2003

Lumbar disc herniation associated with separation of the posterior ring apophysis: analysis of five surgical cases and review of the literature.

BACKGROUND: Separation of the posterior ring apophysis of an adjacent vertebral body can sometimes accompany lumbar intervertebral disc herniation. The condition can be both difficult to detect in conventional radiographs and is somewhat controversial to treat. Although there is general agreement on the frequent need for surgery, there is no consensus on the choice of operation. One procedure, posterior lumbar interbody fusion (PLIF), has never been examined for effectiveness. METHOD: Computed tomography (CT) either or with discography (CTD) was compared to plane radiographs and magnetic resonance imaging (MRI) for its ability to reveal the fragmentation. Five cases were identified and the severity of the condition evaluated using the Japanese Orthopaedic Association's Assessment of Treatment for Low Back Pain (JOA score). The fragments were removed by impaction with a shoe shaped device and posterior lumbar interbody fusion (PLIF) was performed using autogenous iliac crest bone. A second evaluation using the JOA score was performed after a 4 to 5 year follow-up. FINDINGS: CT identified the separation in all 5 cases while plain films showed the defect in two and MRI in none. JOA scores prior to surgery were between 5 and 19 (mean, 13) and between 25 and 29 (mean, 27.4) at follow-up. The scores represented a recovery of 80% to 100%t (mean, 89.4). INTERPRETATION: CT and CT discography (CTD) are the diagnostic tools of choice for detecting this condition. Posterior lumbar interbody fusion (PLIF) is an effective procedure for patients who have low back pain due to lumbar disc herniation accompanied by a separation of the posterior ring apophysis.

Adolescent↗
PubMed2002

A transient ghrelin surge occurs just before feeding in a scheduled meal-fed sheep.

Ghrelin, a gastric-derived peptide, has recently been identified as an endogenous natural ligand for the growth hormone (GH) secretagogue receptor. However, secretory characteristics of ghrelin are still obscure in ruminants. To investigate the diurnal rhythm in ghrelin secretion and its relationship to GH secretion, plasma ghrelin and GH concentrations were determined in Suffolk rams fed with a roughage diet once daily (Experiment 1). Abrupt increases (P<0.05) in plasma ghrelin occurred just before a meal-feeding compared with that at 1h before feeding, then rapidly fell with a minimum during the feeding. A pulsatile surge (P<0.01) in plasma GH concentrations, which seemed to follow a single surge in plasma ghrelin, was observed during the feeding. In Experiment 2, plasma ghrelin and GH were determined in sheep subjected to a pseudo-feeding of 2h to determine whether feed ingestion itself influences ghrelin and GH secretions. Compared with those at 1h before feeding, a tendency of increases (P<0.1) in plasma ghrelin and significant increases (P<0.05) in GH occurred just before and during a pseudo-feeding, respectively. Plasma ghrelin temporally declined within 1h after the start of the pseudo-feeding, and increased again and maintained higher levels during the last period of the pseudo-feeding. These results suggest that the transient surge of ghrelin secretion just before a scheduled meal feeding would not be due to the ingestion of feed, and that a pulsatile increase in plasma GH during the actual- or pseudo-feeding could be induced by the transient ghrelin surge.

Animals↗
PubMed2002

Fan-shaped expanded polytetrafluoroethylene valve in the pulmonary position.

BACKGROUND: Residual pulmonary insufficiency remains a problem after transannular repair in pediatric patients. We have developed fan-shaped monocuspid and bicuspid valves made of expanded polytetrafluoroethylene (ePTFE) membrane for repair of right ventricular outflow tract obstruction in patients with tetralogy of Fallot. METHODS: We studied 20 patients (mean age, 39.6 months) with tetralogy of Fallot. The right ventricular outflow tract was reconstructed with use of a short, wide transannular patch and a fan-shaped valve made of 0.1-mm-thick expanded ePTFE membrane (PRECLUDE Pericardial Membrane, W.L. Gore & Associates, Inc, Flagstaff, AZ). The width of the valve and the outflow patch were constructed so that the neopulmonary annulus was approximately 130% the normal size. RESULTS: A monocuspid valve was used in 17 patients and a bicuspid valve in 3. The mean follow-up time was 32.3 months (range, 14.7 to 56.7 months). Right ventricular function was well maintained in all patients. Valvular motion remained competent in 13 patients (65%). In the remaining 7 (35%), the valve became fixed in the open position. Trivial and mild pulmonary insufficiency was detected in 10 patients with a competent valve and 7 with an incompetent valve. No pressure gradient across the neopulmonary annulus or calcification of the expanded ePTFE membrane was detected in any patient. CONCLUSIONS: The fan-shaped expanded ePTFE valve is a useful substitute with adequate function in transannular right ventricular outflow reconstruction.

Bioprosthesis↗
PubMed2002

The role of plasma endothelin in the Fontan circulation.

BACKGROUND: Various vasoactive substances are released during cardiopulmonary bypass. They may deteriorate pulmonary circulation after the Fontan operation. Effects of plasma endothelin-1 (ET-1), a vasoconstricting peptide, on the Fontan circulation have not been investigated. METHODS: Eleven patients (aged 11.1+/-7.5 years) who underwent the modified Fontan operation (group F) and seven patients (aged 9.9+/-6.0 years) who underwent the biventricular repair (group C) were studied. Plasma samples were obtained for measuring ET-1 on the first postoperative day (Early I), on returning to floor care from the intensive care unit (Early II), and during postoperative cardiac catheterization (Late). RESULTS: Plasma concentrations of ET-1 increased in group F (Early I, 4.37+/-1.78 pg/ml; Early II, 4.07+/-1.90 pg/ml) as compared with the basal value of 1.0+/-0.5 pg/ml. The central venous pressure, which reflects the pulmonary circulatory state, soon after the Fontan operation correlated significantly with the increased ET-1 concentration (y=1.809 x+6.484; r=0.809; p=0.0026). Although the Late ET-1 concentrations in group F were significantly decreased, the central venous pressure and the ET-1 concentrations demonstrated a significant correlation (y=3.074 x +5.427; r=0.740; p=0.0227). CONCLUSIONS: The increased humoral vasoactive substances such as ET-1, which induces pulmonary vasoconstriction following the Fontan operation, may have important implications for the Fontan circulation.

Adolescent↗
PubMed2001

Elevated circulating level of ghrelin in cachexia associated with chronic heart failure: relationships between ghrelin and anabolic/catabolic factors.

BACKGROUND: Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, that may also cause a positive energy balance by stimulating food intake and inducing adiposity. We sought to investigate the pathophysiology of ghrelin in the cachexia associated with chronic heart failure (CHF). METHODS AND RESULTS: Plasma ghrelin was measured in 74 patients with CHF and 12 control subjects, together with potentially important anabolic and catabolic factors, such as GH and tumor necrosis factor (TNF-alpha). Patients with CHF were divided into two groups, those with cachexia (n=28) and those without cachexia (n=46). Plasma ghrelin did not significantly differ between all CHF patients and controls (181+/-10 versus 140+/-14 fmol/mL, P=NS). However, plasma ghrelin was significantly higher in CHF patients with cachexia than in those without cachexia (237+/-18 versus 147+/-10 fmol/mL, P<0.001). Circulating GH, TNF-alpha, norepinephrine, and angiotensin II were also significantly higher in CHF patients with cachexia than in those without cachexia. Interestingly, plasma ghrelin correlated positively with GH (r=0.28, P<0.05) and TNF-alpha (r=0.31, P<0.05) and negatively with body mass index (r=-0.35, P<0.01). CONCLUSIONS: Plasma ghrelin was elevated in cachectic patients with CHF, associated with increases in GH and TNF-alpha and a decrease in body mass index. Considering ghrelin-induced positive energy effects, increased ghrelin may represent a compensatory mechanism under catabolic-anabolic imbalance in cachectic patients with CHF.

Adolescent↗
PubMed2001

Lumen loss in transplant coronary artery disease is a biphasic process involving early intimal thickening and late constrictive remodeling: results from a 5-year serial intravascular ultrasound study.

BACKGROUND: Coronary artery disease is the major cause of late cardiac allograft failure. However, few data exist regarding the natural history of changes in intimal and external elastic membrane (EEM) areas after heart transplantation. METHODS AND RESULTS: In 38 transplant recipients, serial intravascular ultrasound examinations were performed 3.7+/-2.2 weeks after transplantation and annually thereafter for 5 years. In 59 coronary arteries, we compared 135 matched segments among serial studies. In each segment, intravascular ultrasound images were digitized at 1-mm intervals, and mean values of EEM and lumen and intimal areas were analyzed. In the first year after transplantation, the intimal area increased significantly from 1.8+/-1.6 to 3.0+/-2.1 mm(2) (P<0.001). Subsequently, the annual increase in intimal area decreased. EEM area did not change during the first year; however, between years 1 and 3, significant expansion of EEM area occurred (15.4+/-4.6 to 17.2+/-5.4 mm(2), P<0.001). Thereafter, EEM area decreased significantly from 17.2+/-5.4 mm(2) (year 3) to 15.1+/-4.9 mm(2) (year 5, P=0.01). Different mechanisms of lumen loss were observed during 2 phases after transplantation: early lumen loss primarily caused by intimal thickening and late lumen loss caused by EEM area constriction. CONCLUSIONS: This serial ultrasound study revealed that most of the intimal thickening occurred during the first year after heart transplantation. Changes in the EEM area showed a biphasic response, consisting of early expansion and late constriction. Thus, different mechanisms of lumen loss were observed during the early and late phases after transplantation.

Adult↗