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Biomedical subjects

K Matsuyama

Publications and source records attributed to K Matsuyama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Pioglitazone, a specific PPAR-gamma ligand, inhibits aspirin-induced gastric mucosal injury in rats.

BACKGROUND: Neutrophils activation and tumour necrosis factor-alpha (TNF-alpha) induction play a critical role in aspirin-induced gastric mucosal injury. Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, has recently been implicated as a regulator of inflammatory responses. The aim of the present study was to determine whether pioglitazone, a specific PPAR-gamma ligand, can ameliorate aspirin-induced gastric mucosal injury in rats, and whether the agent can inhibit the increase in neutrophil accumulation associated with TNF-alpha expression. METHODS: Aspirin-induced injury was produced by the intragastric administration of aspirin (200 mg/kg) and HCl (0.15 N, 8.0 mL/kg). Pioglitazone was given to the rats by gastric intubation 1 h before the aspirin administration. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in gastric mucosa as indices of lipid peroxidation and neutrophil infiltration. The gastric concentration of TNF-alpha and the expression of TNF-alpha mRNA was determined by ELISA and reverse transcriptase-polymerase chain reaction. RESULTS: The intragastric administration of acidified aspirin induced hyperemia and haemorrhagic erosions in rat stomachs. The increase in the total gastric erosive area after aspirin administration was significantly inhibited by treatment with pioglitazone in a dose-dependent manner. The increases in thiobarbituric acid-reactive substances and myeloperoxidase activity after aspirin administration were both significantly inhibited by pre-treatment with pioglitazone (10 mg/kg). The gastric content of TNF-alpha increased and the expression of TNF-alpha mRNA was up-regulated after aspirin treatment. However, the peak TNF-alpha mRNA expression 1 h after aspirin administration was inhibited by pioglitazone. CONCLUSION: Based on these data, the beneficial effects of pioglitazone on aspirin-induced gastric mucosal injury may be attributed to its anti-inflammatory properties.

Animals↗
PubMed2001

Variation of des-gamma-carboxyprothrombin (PIVKA-II) levels in cord blood throughout gestation.

The variation of des-gamma-carboxyprothrombin (PIVKA-II, protein induced by vitamin K absence) levels in umbilical cord blood throughout gestation was examined using a highly sensitive method, electrochemiluminescence immunoassay (ECLIA). PIVKA-II levels in infants without any complications were low, but modestly high, exceeding the normal range of healthy adults during the preterm period, followed by a remarkable increase after the 37th week of gestation. Among infants complicated with severe preeclampsia a marked increase of PIVKA-II levels was observed in preterm infants, showing a good correlation with the existence ofinfarctions on the placenta. On the other hand, among infants complicated with preterm premature rupture of the membranes (PROM) in which antibiotics were administered during the prenatal period, a moderate elevation of PIVKA-II levels was observed. These data suggest that the normal range of PIVKA-II in fetuses is modestly high compared with adults and any deficient status of vitamin K would not exist throughout the preterm period. Nevertheless, the vitamin K status might readily fall into a deficient condition in term infants. Furthermore, it is notable that vitamin K deficiency would be induced in complicated gestation with severe preeclampsia and medication with antibiotics.

Biomarkers↗
PubMed2001

Early and late results of partial plication annuloplasty for congenital mitral insufficiency.

BACKGROUND: Partial plication annuloplasty is the main technique for congenital mitral insufficiency because this technique allows the mitral anulus to grow, in contrast to ring annuloplasty. However, this technique is not satisfactory for mitral insufficiency with some anomalies of the mitral valve apparatus. METHODS: Forty-one patients underwent partial plication annuloplasty for mitral regurgitation from July 1979 to December 1998. Mitral regurgitation associated with an atrioventricular defect, an atrioventricular discordance, and a univentricular heart was excluded from this study. RESULTS: There were no early or late deaths. In early results, partial plication annuloplasty was more effective for mitral regurgitation with abnormality of the posterior leaflet (n = 14) or normal leaflet motion (n = 8) than with abnormality of the anterior leaflet and its apparatus (n = 14) or absence of chordae (n = 4). The mean follow-up period was 145.8 months. During the follow-up period, 2 patients underwent mitral valve replacement, and a third patient underwent mitral valve repair with partial plication annuloplasty after the first repair. The main cause of mitral regurgitation of 2 of the 3 patients was absence of chordae. The actuarial freedom from reoperation rate was 94.9% +/- 3.6%, 91.9% +/- 4.7%, and 91.9% +/- 4.7% at 5, 10, and 15 years after the operation, respectively. CONCLUSION: Early and long-term results of partial plication annuloplasty were acceptable for congenital mitral insufficiency with any type of malformation of the mitral valve, and results were excellent with abnormality of the posterior leaflet and its apparatus or normal leaflet motion. However, late results were suboptimal for mitral regurgitation with absence of chordae. Other techniques, such as artificial chorda replacement, should be adapted in these cases.

Actuarial Analysis↗
PubMed2001

Preparation and characterization of biodegradable or enteric-coated microspheres containing the protease inhibitor camostat.

We have produced biodegradable or enteric-coated microspheres containing camostat mesylate, a protease inhibitor, using a water-oil-water emulsion solvent evaporation method. The characteristics of the microspheres were determined. When polylactic acid, a biodegradable polymer, was used as a wall material, the optimized microsphere obtained showed a loading efficiency of almost 95% and had a mean diameter of 30 microm. This microsphere showed a sustained-release profile, with nearly 25% of drug being released at seven days in a dissolution test. When hypromellose acetate succinate (AS-HG type, with a high content of succinyl group) was used as an enteric wall material, optimized microspheres showed a loading efficiency of almost 80%. In this case, pH 3.0 citrate buffer was used as an internal aqueous phase, and citrate buffer containing 0.5% polyvinylalcohol was used as the external aqueous phase. These microspheres showed a rapid release profile in pH 6.8 buffer, whereas the release was extremely slow in pH 1.2 buffer. Hypromellose acetate succinate microspheres were also prepared containing 10% (w/w) N-benzoyl-dl-arg-4-nitroanilide as a model substrate for trypsin, with or without 5% (w/w) camostat. These microspheres were incubated in pH 6 or 7 buffer containing trypsin at 37 degrees C. When camostat was included in the microspheres, the substrate was protected from attack by trypsin, while in the absence of camostat, the released substrate was immediately attacked by trypsin to produce the degradation product N-benzoyl-dl-arginine.

Buffers↗
PubMed2001

Preparation and characterization of insulin-loaded acrylic hydrogels containing absorption enhancers.

The objectives of this study were to prepare insulin-loaded acrylic hydrogel formulations containing various absorption enhancers, to perform in vitro and in vivo characterization of these formulations, and to evaluate the factors which affecting insulin availability on rectal delivery of insulin using this hydrogel system. The acrylic block copolymer of methacrylic acid and methacrylate, Eudispert, was used to make the hydrogel formulations. As absorption enhancers, 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CyD), lauric acid (C12), or the sodium salt of C12 (C12Na), were incorporated into the hydrogels. In an in vitro release test, the release rate of insulin from the hydrogels decreased as the polymer concentration of the hydrogel increased. The addition of C12Na to the hydrogel further increased the insulin release rate, which was greater at higher concentrations of the enhancer. A portion of the C12Na was found to remain bound to the acrylic polymer in dissolution medium. Serum insulin levels were determined at various time points after the administration of insulin solution or insulin-loaded (50 units/kg body weight) Eudispert hydrogels containing 5% (w/w) of C12, C12Na, or DM-beta-CyD to in situ loops in various regions of the rat intestine. The most effective enhancement of insulin release was observed with formulations containing C12Na. The bioavailability of insulin from the hydrogels was lower than that from the insulin solutions. Hydrogel formulations containing 7% or 10% Eudispert remained in the rectum for 5 h after rectal administration. However, the 5% (w/w) C12Na solution stained with Evan's-blue had diffused out and the dye had reached the upper intestinal tract within 2 h. Finally, the rectal administration of insulin-loaded hydrogels, containing 4%, 7%, or 10% (w/w) Eudispert and 5% (w/w) of enhancer (C12, C12Na, or DM-beta-CyD) to normal rats was shown to decrease serum glucose concentrations. The greatest effect was found with insulin-loaded 7% (Eudispert) hydrogel containing C12Na which having cosiderable large insulin release rate and bioadhesive characteristics.

Acrylates↗
PubMed2001

A new method for evaluating the bitterness of medicines by semi-continuous measurement of adsorption using a taste sensor.

We describe a new method for the evaluation of the bitterness of medicines by semi-continuous measurement of adsorption using a multichannel taste sensor or 'electric tongue'. The bitterness of 10 basic medicines was evaluated by both the taste sensor and in human gustatory sensation tests with 11 volunteers. The sensor part of the taste sensor consists of eight electrodes made of lipid/polymer membranes. Three variables were obtained from the taste sensor data: sensor output (S), the change of membrane potential caused by adsorption, corresponding to aftertaste (C), and the ratio C/S. These variables were used to predict an estimated bitterness score in multiple regression analysis. Semi-continuous measurement of C (every 30 s up to 150 s) was adopted as an additional explanatory variable, and the attenuation rate of C was defined as C'. These data were also subjected to multiple regression analysis. The correlation coefficient (r) estimated for the bitterness score predicted by the taste sensor, using C' for channel 2 and C/S for channel 4, and the score obtained by human gustatory sensation, was 0.824. This value was greater than that obtained using C/S for both channels 2 and 4 (0.734). The method described in the present study seems to offer good predictability for the evaluation of bitterness.

Adsorption↗
PubMed2001

Clinical characteristics of patients with constrictive pericarditis after coronary bypass surgery.

Constrictive pericarditis (CP) is an unusual sequela of cardiac surgery, so the present study evaluated the clinical characteristics of patients with CP after coronary artery bypass grafting (CABG). Four hundred and sixty-three patients who underwent isolated CABG between January 1989 and March 1999 were examined retrospectively. The first choice of treatment for postoperative pericardial effusion was non-steroid anti-inflammatory agents, and an increased dose of diuretics. The second treatment choice was corticosteroids or pericardial drainage. When CP was suspected during the follow-up period (mean, 54+/-31 months), cardiac catheterization was carried out to establish the diagnosis. Of the 463 patients undergoing CABG, there were 11 (2.4%) who developed CP after surgery. The median time to the onset of symptoms after CABG was 4 weeks (range, 3-96 weeks). On univariate and multivariate analysis, normal left ventricular ejection fraction, warfarin administration, and early postoperative pericardial effusion were significantly associated with a greater potential of postoperative CP. The effusion was bloody in all cases of pericardial drainage despite warfarin therapy. Not draining the postoperative effusive pericardial effusion was a risk factor for the development of CP. Pericardial drainage for patients with significant effusion after CABG is important for the prevention of subsequent CP, especially in those patients being treated with warfarin or with normal left ventricular function.

Aged↗
PubMed2001

[Surgery for thoracic aortic aneurysms involving the distal arch through a left thoracotomy].

Surgical outcome for thoracic aortic aneurysms involving the distal arch via a left thoracotomy using retrograde cerebral perfusion combined with profound hypothermic circulatory arrest was reviewed. Twelve patients with a atherosclerotic aortic aneurysm between 1994 and 1997 were involved. A proximal aortic anastomosis was made by means of an open aortic technique. For the first four patients, oxygenated arterial blood from cardiopulmonary bypass was perfused retrogradely through a venous cannula positioned into the right atrium. In the last eight cases, venous blood provided by a low-flow perfusion of the lower half body via the femoral artery, which was still oxygen-saturated, was circulated passively in the brain in a retrograde fashion with the descending aorta clamped. Prosthetic replacement was done between the distal arch and the proximal descending aorta in 6 patients and from the distal arch to the entire descending thoracic aorta in 6 patients. The median duration of hypothermic circulatory arrest and continuous retrograde cerebral perfusion was 36 minutes and 33 minutes respectively. The overall outcome was satisfactory without early mortality--all patients survived, although an octogenarian died of respiratory failure 1 year postoperatively. Another octogenarian with a ruptured aneurysm developed delay of meaningful consciousness, and other two patients with a severely atherosclerotic aneurysm suffered permanent neurological dysfunction (stroke) presumably due to an embolic episode. The safe and simple combination of profound hypothermic circulatory arrest, retrograde cerebral perfusion, and open aortic anastomosis protects the brain adequately and produces satisfactory results in surgery for aortic aneurysms involving the distal arch through a left thoracotomy.

Aged↗
PubMed2001

[A case of docetaxel-resistant breast cancer responsive to paclitaxel therapy].

A 73-year-old woman underwent docetaxel therapy for lung metastasis from breast cancer after having received CAF therapy. Because of the progressive disease due to secondary resistance to docetaxel, the patient was given three courses of paclitaxel therapy (60 mg/m2, day 1, 8, 15 and 22, repeated every 6 weeks). The paclitaxel therapy brought about no adverse effects and a 51%-reduction in the size of the metastatic lung tumor (PR). Although the duration of the response to the paclitaxel therapy was limited to about one month due to progression of a brain metastasis, paclitaxel therapy may be effective against docetaxel-resistant breast cancer.

Aged↗
PubMed2001

Aortic laceration due to prolapse of the bicuspid aortic valve: case report.

Reports of aortic regurgitation due to rupture of the aortic valve commissures are rare. Prompt surgical intervention is necessary, as the condition results in rapid, progressive heart failure and subsequent death. We report the case of a 78-year-old man who presented with aortic laceration and cardiac tamponade that was probably induced by prolapse of the bicuspid aortic valve. We speculate that prompt initial surgery may have prevented aortic laceration and cardiac tamponade in this patient. Thus, in order to optimize clinical outcome, clinicians must consider early, precautionary surgical management in patients who have sudden cardiac failure due to aortic regurgitation associated with prolapse of the bicuspid aortic valve.

Aged↗
PubMed2001

[Non-small cell lung cancer with liver metastasis responsive to gemcitabine--a case report].

A 56-year-old male patient underwent a right upper lobectomy and lymph node dissection for non-small cell lung cancer in March 1994. Multiple lung metastases in the right lung were found 45 months after the operation, and chemotherapy with docetaxel was administered. A liver metastasis was detected 11 months later, and it was refractory to docetaxel. Therefore, the patient was treated with cisplatin, mitomycin C and vinorelbine, which resulted in no change to the liver metastasis. He was next treated with gemcitabine, which resulted in a partial response of the liver metastasis. The adverse effects of gemcitabine were Grade 3 thrombocytopenia and Grade 2 neutropenia. The response duration for gemcitabine therapy was three months.

Adenocarcinoma↗
PubMed2001

De Vega annuloplasty and Carpentier-Edwards ring annuloplasty for secondary tricuspid regurgitation.

BACKGROUND AND AIM OF THE STUDY: Residual or recurrent tricuspid regurgitation (TR) has been reported after several types of surgical repair. The development of late TR is an important complication of left heart surgery. The results of De Vega annuloplasty were compared with those obtained after Carpentier-Edwards ring (CE ring) annuloplasty in patients with secondary TR. METHODS: The records of 45 patients who underwent surgery for secondary TR between January 1995 and July 2000 were reviewed retrospectively. Twenty-eight patients underwent De Vega annuloplasty, and 17 had a CE ring annuloplasty. The groups were similar with respect to associated cardiac lesions. No significant preoperative differences were observed in NYHA functional class, TR grade, and pulmonary artery pressure between the two groups. RESULTS: One CE patient died of left ventricular dysfunction after postoperative bleeding. The 28 De Vega patients and remaining 16 CE patients had an uneventful recovery, and were discharged. Tricuspid ring size after repair was similar between groups. Mean (+/- SD) follow up in the entire patient cohort was 39+/-23 months (range: 6 to 75 months). TR recurrence was rated as grade II or III in 13 patients (45%) after De Vega annuloplasty, but was grade II or III in only one patient (6%) patient after CE ring annuloplasty. There was a significant difference in TR recurrence between the groups (p = 0.027), but no significant difference in NYHA class. CONCLUSION: CE ring annuloplasty significantly decreased the recurrence of TR; thus, CE ring annuloplasty is superior to De Vega annuloplasty in patients with secondary TR.

Aged↗
PubMed2001

[Emergent surgical treatment of type A acute aortic dissection in an elderly patient].

An 86-year-old man with severe chest pain and shock was transferred to our hospital. Computed tomography revealed type A aortic dissection with cardiac tamponade. He needed intubation and closed chest massage preoperatively. At operation, intrapericardial space was filled with clotted blood and rupture of the ascending aorta was confirmed. He underwent a successful emergency graft replacement of the ascending aorta. Postoperative course was uneventful except for mild hemianopsia due to cerebral infarction. He had recovered to be able to walk and is doing well.

Acute Disease↗
PubMed2000

beta-blocker therapy in patients after aortic valve replacement for aortic regurgitation.

BACKGROUND: beta-blocker therapy for dilated or ischemic cardiomyopathy is now an accepted and effective treatment. However, little is known about its efficacy in patients with postoperative impaired left ventricular function. This retrospective study was designed to assess the effects of beta-blocker therapy in patients after aortic valve replacement (AVR) for aortic regurgitation (AR). METHODS: A total of 59 patients who underwent AVR for chronic AR were assigned to four groups. Twelve patients were treated with both ACE inhibitors and beta-blockers, 12 patients with only ACE inhibitors, eight patients with only beta-blockers, and 27 patients without beta-blockers or ACE inhibitors. A postoperative echocardiographic study was performed one year after surgery. RESULTS: The heart rate was significantly reduced in patients with beta-blockers despite the use of ACE inhibitors after surgery. Postoperative left ventricular volume was more significantly decreased in beta patients than in non-beta patients despite the use of ACE inhibitors. There were also significant reductions in left ventricular mass index in ACE+beta patients compared to ACE+non-beta patients. However, there were no significant differences in NYHA functional class and survival rate between beta patients and non-beta patients. CONCLUSIONS: beta-blocker therapy may improve cardiac performance by reducing cardiac volume and mass in patients with impaired LV function after AVR for AR.

Adrenergic beta-Antagonists↗
PubMed2000

Bisphosphonate therapy for bone metastases from breast cancer: clinical results and a new therapeutic approach.

BACKGROUND: We evaluated the usefulness of bisphosphonate (BIS) monotherapy, the safety of rapid infusion of BIS and the efficacy of BIS-sequential therapy for bone metastases from breast cancer. PATIENTS AND METHODS: Twenty-nine patients with bone metastasis or invasion were treated with BIS monotherapy. Each BIS (pamidronate 30 mg, alendronate 10 mg, or incadronate 10 mg) was infused over 30 minutes every two weeks a median of 12 times. RESULTS: With BIS therapy, five patients (17%) showed partial response of the bone lesions, and eighteen patients (64%) had pain relief. Of the nine patients treated with BIS-sequential therapy, one (11%) showed a partial response of the bone metastases, three (33%) had pain relief, and one (11%) showed a decrease in the serum tumor marker level. CONCLUSION: BIS therapy is effective against bone metastases from breast cancer, and rapid infusion of BIS is both safe and convenient for patients. BIS-sequential therapy can be a unique therapeutic option in some cases.

Adult↗
PubMed2000

Repeated procedure after radical surgery for tetralogy of Fallot.

BACKGROUND: Although the immediate results of radical operation for tetralogy of Fallot are excellent, long-term follow-up has shown that the number of repeated procedures has increased in many institutions. We describe patients who underwent a second or third procedure after radical operation for tetralogy of Fallot. METHODS: Between April 1981 and August 1996, we operated on 44 patients for the second time and on 4 for the third time after radical operation for tetralogy of Fallot. Indications for a second and third procedure included right ventricular outflow tract obstruction in 38 patients, infective endocarditis in 4, and isolated residual ventricular septal defect in 3. RESULTS: One patient died after concomitant replacement of the pulmonary and tricuspid valves. Three patients who underwent sternotomy more than twice (before the second or third operation) underwent accidental cardiovascular trauma during this procedure (30%). Moreover, when patients underwent more than two sternotomy procedures before the repeated operation for tetralogy of Fallot, the total bypass time, interval between cessation of the cardiopulmonary pump to completion of the operation, amount of blood transfusion, and length of intensive care unit stay were significantly higher compared with those who underwent less than two sternotomy procedures (p < 0.05). Right ventricular outflow tract obstruction was the main indication for a second operation. After the second operation for right ventricular outflow tract obstruction in 35 patients, the preoperative right ventricle to left ventricle pressure ratio decreased significantly (from 0.75 +/- 0.13 to 0.51 +/- 0.12; p < 0.0001). However, the right ventricle to left ventricle pressure ratio did not significantly decrease in patients who underwent a third procedure to treat right ventricular outflow tract obstruction. CONCLUSIONS: The surgical results of a second procedure after radical operation for tetralogy of Fallot were acceptable. However, the risk of accidental cardiovascular trauma during dissection was high among patients who underwent sternotomy more than twice before repeat operation.

Adolescent↗
PubMed2000

The cat neostriatum: relative distribution of cholinergic neurons versus serotonergic fibers.

The distribution of choline acetyltransferase (ChAT)-containing neurons and serotonin (5-HT)-containing nerve fibers in the cat neostriatum was investigated by use of immunohistochemical techniques. Both ChAT- and 5-HT-staining techniques were applied to alternate brain sections, thereby allowing a precise comparison of the distribution pattern of ChAT-immunopositive cells (ChAT cells) and 5-HT-immunopositive fibers (5-HT fibers). In the neostriatum, ChAT cells were strongly stained throughout their cell bodies and proximal (first-order) dendrites. The majority of them were multipolar cells with a soma diameter of 20-50 microm (long axis)x10-30 microm (short axis). In the caudate nucleus, ChAT cells were evenly and diffusely distributed except for the dorsolateral region of its rostral half, in which latter region they were distributed in loosely formed clusters. In the rostral portion of the putamen, the density of ChAT-cell distribution was like that in the medial region of the caudate nucleus. In contrast, this distribution was more dense in the caudomedial region of the putamen, adjacent to the globus pallidus. 5-HT fibers in the neostriatum were dark-stained, of quite fine diameter (<0.6 microm), and they contained small, round varicosities (diameter, usually 0.5-1.0 microm, but some >1.0 microm). Such 5-HT fibers were distributed abundantly throughout the caudate nucleus and putamen. In the rostrocaudal portion of the caudate nucleus, their density was high in its dorsal and ventral components, and low in the middle component. Throughout the putamen, 5-HT fibers were distributed homogeneously in the mediolateral and dorsoventral directions. In the caudal portion of the putamen adjacent to the globus pallidus, the 5-HT fibers had a higher density while maintaining their homogenous distribution pattern. In the two main divisions of the striatum, the so-called 'patch' (acetylcholinesterase (AChE)-poor) and 'matrix' (AChE-rich) compartments, there was a near-even distribution of 5-HT fibers and terminals. The above results suggest that the 5-HT-dominated, raphe-striatal pathway is optimally arranged for modulating the activity of both the intrinsic and the projection neurons of the neostriatum.

Acetylcholine↗