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Biomedical subjects

M Kawauchi

Publications and source records attributed to M Kawauchi.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Successful redo-AVR with cryopreserved allograft for prosthetic valve endocarditis : report of a case].

A 20-year-old male undergoing mechanical aortic valve replacement suffered from prosthetic valve endocarditis by Coagulase negative Staphylococci 3 months postoperatively. Echocardiography revealed left ventricular distention, severe paravalvular leakage, valve detachment and large periannular abscess adjacent to the left main coronary artery. Redo-AVR was successfully performed with a cryopreserved aortic allograft by cylinder technique. The orifice of abscess was covered with the aortic wall of the graft. Postoperative echocardiography showed trivial central regurgitation and the abscess cavity went on vanishing. He discharged from hospital 2 months later without any symptom.

Abscess↗
PubMed1996

[Echocardiographic evaluation of hemodynamic function of CarboMedics heart valve in the aortic position in patients with small aortic annuli].

Hemodynamic parameter of CarboMedics heart valve in the aortic position was evaluated using Doppler echocardiography in 46 patients with small aortic annuli. The size of prosthetic valve were 19 mm in 6 cases, 21 mm in 15 and 23 mm in 25. In patients with 19 mm valve, trans-valvular peak pressure gradient was 42.2 +/- 11.8 mmHg, mean pressure gradient was 17.3 +/- 9.3 mmHg, and left ventricular systolic pressure was 174 +/- 12 mmHg. These values were significantly larger than those of the other two groups. Effective orifice area index, discharge coefficient, doppler velocity index and stroke volume showed no significant difference among each group. After aortic valve replacement for aortic stenosis, left ventricular mass decreased to around 70% of preoperative value in all groups, but significant left ventricular hypertrophy remained at two years postoperatively. We conclude that hemodynamic performance of CarboMedics heart valve in the aortic position was satisfactory, although 19 mm valve seemed to be fairly small for adult patients and deliberate patient selection is necessary.

Adult↗
PubMed1995

Expression of Cu,Zn-superoxide dismutase mRNA after cold and contusion injury in the rat brain.

We analyzed the expression of Cu,Zn-superoxide dismutase (SOD) mRNA in both contusion and cold injury. Twenty-three rats were divided into 3 groups: a control group, a contusion group, and a cold injury group. Six hours after the injury, the rats were decapitated and the gray matter was resected from 3 portions: the core of the injured cortex, its periphery, and a distal portion on the non-lesion side. Based on the specific gravity of each sample, almost the same degree of edema developed in both injury groups. The mRNA expression in the cold injury group, however, significantly decreased in all portions. The extremely low temperature associated with cold injury is a possible cause of the decrease in Cu,Zn-SOD mRNA.

Animals↗
PubMed1995

Long-term results of surgical treatment of intracardiac tumors. Effectiveness and limitation of surgical treatment.

Twenty-five cases of intracardiac tumors were operated upon from 1975 through 1994. Twenty-four operative survivors were followed up. The follow-up period ranged from 2 months to 19 years with an average of 8 years. The histological diagnoses of the tumors were as follows: benign tumors 21 (myxoma 20, leiomyoma 1) and malignant tumors 4 (sarcoma 3, carcinoma 1). In 21 cases, tumors had cardiac origins, while there were four intracardiac tumors which had originated in other organs and extended transvenously to the intracardiac cavity (leiomyoma 1, sarcoma 2, carcinoma 1). The results of surgical treatment of intracardiac benign tumors were satisfactory, regardless of their origins and multiplicity, both in the short-term and in the long-term. On the other hand, the long term results for malignant intracardiac tumors were extremely poor, although their excision or resection had a beneficial effect on the hemodynamics in patients with congestive heart failure or cardiogenic shock.

Adult↗
PubMed1995

Meningiomas arising from the falcotentorial junction. Clinical features, neuroimaging studies, and surgical treatment.

Meningiomas arising from the falcotentorial junction are extremely rare. The authors describe the clinical features, neuroimaging studies, and results of surgical treatment of meningiomas of the falcotentorial junction and clarify the characteristics of this lesion based on a review of the literature and seven patients treated at their institution. The most common symptoms resulted from intracranial hypertension. Upward-gaze palsy appeared in only one patient. Computerized tomography (CT) showed no specific findings, but there was no evidence of edema around the tumor. Magnetic resonance (MR) imaging revealed a round, smooth-bordered mass with a peritumoral rim, without edema, and showing marked contrast enhancement. The multiplanar capability of MR imaging delineated the relationship between the tumor and adjacent structures better than did CT. Detailed knowledge of the vascular structures, especially evidence of occlusion of the galenic venous system and the development of collateral venous channels, is critical for successful surgery; stereoscopic cerebral angiography is necessary to achieve this aim. The seven patients described developed five types of collateral venous channels: through the basal vein of Rosenthal to the petrosal vein, through the veins on the medial surface of the parietal and occipital lobes to the superior sagittal sinus, through superficial anastomotic veins, through veins of the posterior fossa to the transverse or straight sinus, and through the falcian veins to the superior sagittal sinus. The first three types mainly developed after occlusion of the galenic system. The tumors were removed through the occipital transtentorial approach with a large window at the posterior part of the falx. A favorable prognosis for patients undergoing surgical treatment of falcotentorial junction meningiomas can be expected if detailed neuroimaging studies and microsurgical techniques are used.

Adult↗
PubMed1995

[Pulsatile total cavopulmonary shunt for hypoplastic right heart syndrome with abnormal systemic venous return--a case report].

A pulsatile total cavopulmonary shunt was successfully performed on a 5-year-old girl with hypoplastic right heart syndrome associated with abnormal systemic venous return; at the same time, modified mitral valve replacement was performed for mitral regurgitation. The right atrium, tricuspid valve and right ventricle were all extremely dimunitive. The diameter of the tricuspid valve was 50% of normal and the volume of the right ventricle was 8.6% of normal. In addition, there were severe subpumonary stenosis, a restrictive ventricular septal defect (VSD) and an atrial septal defect (ASD). The bilateral superior venae cavae (SVCs) and the hepatic vein drained to the left atrium, and the inferior vena cava was infrahepatically interrupted with a hemiazygos connection to the left superior vena cava. At the operation, each SVC was anastomosed end-to-side to each branch of the pulmonary artery (PA). The restrictive ventricular septal defect and stenotic subpulmonary lesion were left. The diameter of the ASD was reduced from 12 mm to 7 mm. The main PA was neither divided nor banded. The pulsatile blood flow from the left heart to the PA was regurated by a native restrictive VSD and stenotic subpulmonary lesion, and that from the right heart via the ASD was limited by reducing the size of the ASD. These described anatomic arrangements produced adequate antegrade pulsatile flow in the PA, which might prevent the development of pulmonary arteriovenous fistulae and, besides permit transfer of drainage of the hepatic vein from the left to the right atrium via the ASD in future.

Arteriovenous Shunt, Surgical↗
PubMed1995

[The left-sided atrioventricular replacement of corrected transposition of the great arteries through a left thoracotomy].

In a 17-year-old female with dextrocardia and corrected transposition of the great arteries, whose VSD and PFO had been surgically closed through median sternotomy two years previously, the left-sided atrioventricular valve replacement was performed for its severe insufficiency. The left anterolateral thoracotomy was chosen to have good visual field and to prevent unnecessary dissection of the adhesion. The postoperative course was uneventful.

Adolescent↗
PubMed1994

Induction of Cu,Zn-superoxide dismutase after cortical contusion injury during hypothermia.

To determine the effect of hypothermia on superoxide injury after cerebral contusion, the induction of Cu,Zn-superoxide dismutase was examined 6 h after contusion in rats using Northern blotting. Cu,Zn-superoxide dismutase gene expression increased at the periphery of the contusion, which may indicate the severity of the superoxide stimulus. This increase was preserved after contusion under hypothermia, which may show that superoxide injury is still severe although brain edema is decreased.

Animals↗
PubMed1994

Detection of endogenous albumin as an index of blood parenchymal border alteration.

We used a microdialysis technique to establish a method to detect sequential changes in disruption of the blood parenchymal border. Twelve cats were divided into two groups; one group underwent occlusion of the middle cerebral artery for 60 minutes, the other a cold injury model. Microdialysis probes were implanted bilaterally into the white matter, and dialysates were collected successively at 30 minute intervals for 6 hours in the occlusion model and 4 hours in the cold injury model. Regional cerebral blood flow was measured simultaneously using the hydrogen clearance method. The water content of the white matter was measured using specific gravity. The proteins in the dialysate were analyzed using electrophoresis with silver stain, and, with densitometric analysis, the density of the 66.2 kDa band was quantified as albumin. The ratio of this density to the preoperative density was defined as the "albumin index." On the side of the lesion in the cold injury model, this index significantly increased 3 hours after the cold injury compared with the contralateral side, and a correlation between the water content and this index was observed. The albumin index was believed to indicate the severity of disruption of the blood parenchymal border.

Animals↗
PubMed1994

Endogenous superoxide dismutase activity in reperfusion injuries.

To elucidate the relationship between reperfusion injuries and free radicals, we monitored the endogenous superoxide dismutase (SOD) activity by intracerebral microdialysis. Six cats underwent a transient occlusion of the middle cerebral artery for 60 minutes after microdialysis probes were implanted bilaterally into the white matter under the ectosylvian gyrus. Dialysates were collected at 30 minute intervals over the course of 5 hours after reperfusion. The SOD activity of the dialysates was measured with electron spin resonance spectrometry. Regional cerebral blood flow was measured simultaneously and the water content of the white matter was assayed at the end of the experiment. After reperfusion, SOD activity increased significantly in the first 30 minutes compared with the preoperative value, and decreased over 4-4.5 hours and 4.5-5 hours in the occluded side. The water content in the occluded side was significantly higher than that in the contralateral side. The highest SOD activity during reperfusion and the water content in the occluded side seemed to correlate, although not significantly. A leakage of intracellular SOD or a reactive increase of SOD activity in response to the reperfusion injury are possible mechanisms of increase in extracellular SOD.

Animals↗
PubMed1994

Superoxide scavenging activity in vitro and in the cerebral extracellular space measured by microdialysis.

Using the electron spin resonance (ESR) spin-trapping method and a high molecular cut-off membrane, we measured the superoxide scavenging activity in dialysates obtained from microdialysis. The activity in the dialysates of the Cu,Zn-superoxide dismutase (SOD) solution and feline serum were measured in vitro, and the recovery rate was calculated to be 12.88 +/- 0.9% in Cu,Zn-SOD solution and 21.52 +/- 4.38 in feline serum, which was significantly different. This difference was believed to originate from the higher osmotic pressure due to proteins in the serum and substances other than Cu,Zn-SOD that acted as antioxidants in the serum. In an in vivo study, microdialysis probes were implanted into the cerebral hemispheres in 6 cats. The sequential changes of superoxide scavenging activity were measured for 16 h and during induced cardiac arrest. No significant difference was observed and the microdialysis technique itself did not seem to cause the significant alteration of the activity in the extracellular space, although at cardiac arrest, the activity varied widely. This method can be used to study the reaction against superoxide injury in further experiments involving brain insult.

Animals↗
PubMed1994

Superoxide scavenging activity in the extracellular space of the brain in forming edema.

We carried out a time course study of cerebral superoxide scavenging activity using a modified microdialysis technique. Twelve cats were divided into two groups; six were the reperfusion injury models, and six were cold injury models. In the reperfusion injury model, dialysates were collected during 60 minutes of middle cerebral artery occlusion and at 300 minutes during reperfusion. In the cold injury model, dialysates were collected 240 minutes after the injury. Regional cerebral blood flow on the injured side decreased during occlusion in the reperfusion injury model and 60 minutes after injury in the cold injury model. In the reperfusion model, superoxide scavenging activity, as determined with electron spin resonance, increased in the first 30 minutes and decreased 300 and 330 minutes after occlusion. In the dialysate, albumin increased 180 minutes after cold injury, which may show the progress of vasogenic edema. An increase in water content was observed on the injured side of both models, and a correlation between water content and superoxide scavenging activity was found in the reperfusion injury model. By this technique, a method of detecting the alteration of superoxide scavenging activity in the extracellular space of the brain was established.

Animals↗
PubMed1994

Experimental analysis of brain surface elastance in cats.

Brain surface elastance, defined as the pressure needed to compress the cortex 3 mm, was measured using the ophthalmodynamometer in six cats using three burr holes (frontal, parietal, and occipital) on each side. An intracranial mass was then used to compress the right side for 3 hours, and cardiac arrest was induced after the mass was removed. Elastance was measured four times: before insertion of the mass, 10 and 70 minutes after removal of the mass, and 60 minutes after cardiac arrest. The results showed that: brain surface elastance does not change between sides, but varies among regions with the parietal region having the highest elastance; elastance increases after compression by an intracranial mass, but not after cardiac arrest; and stiff brain tends to restore poorly. Elastance is apparently increased by the formation of edema. Measuring brain elastance may be useful in predicting brain restoration subsequent to removal of mass lesions.

Animals↗