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Biomedical subjects

M Machii

Publications and source records attributed to M Machii.

14 recordsLinked to original sources
PubMed2001

Protection of the spinal cord with pentobarbital and hypothermia.

BACKGROUND: Ischemic spinal cord damage during thoracic aortic operations has not been eliminated despite application of various adjuncts. We experimentally investigated the protective effects of pentobarbital and hypothermia on the spinal cord subjected to ischemia. METHODS: Among nine groups of 6 rabbits each, groups AI to AIII underwent 20-minute infrarenal aortic occlusion, and groups BI to BVI underwent 40-minute occlusion. Five milligrams per kilogram of pentobarbital was administered to groups AII and BII; 10 mg/kg in groups AIII, BIII, and BVI; 20 mg/kg in group BIV; and none in groups AI, BI, and BV. In groups BV and BVI, hypothermia was induced. Forty-eight hours postoperatively, the motor function of the lower limbs was evaluated. RESULTS: Statistically significant recovery of motor function was observed in animals in groups AII, AIII, BIII, BIV, BV, and BVI. CONCLUSIONS: Pentobarbital showed dose-dependent protective effects of the spinal cord. Moderate hypothermia alone also showed protective effects. Combined use of pentobarbital and hypothermia resulted in highly significant recovery of spinal cord function.

Animals↗
PubMed2000

Free-floating left atrial ball thrombus early after mitral valve replacement.

A 61-year-old woman was found to have a free-floating ball, thrombus in the left atrium on echocardiographic examination 2 weeks after mitral valve replacement and tricuspid, annuloplasty. The free-floating thrombus was successfully, removed by an open-heart procedure without clinical sequelae. The diagnostic value of routine echocardiography on follow-up of valve surgery is emphasized.

Female↗
PubMed1999

Aortic stump tailoring with GRF glue and a felt strip.

We describe herein a new technique of aortic stump tailoring for aortic dissection. This method involves the application of gelatine-resorcin-formalin (GRF) glue and a felt strip, with manipulation using the balloon of an endotracheal tube. The conjoined wall consists of three layers, but it is completed like a single layer. This procedure facilitates anastomosis to the graft in the next step.

Aortic Dissection↗
PubMed1999

Stent grafting for aortic dissection.

We report the successful treatment of a patient with Stanford type B aortic dissection, "thrombosed" type with ulcer-like projections, by insertion of a stent-graft. The false lumen completely disappeared within 1 year after surgery. This maturing procedure is promising in the treatment of thrombosed, aggravated aortic dissection.

Aortic Dissection↗
PubMed1997

Hypoplastic aortic arch morphology pertinent to growth after surgical correction of aortic coarctation.

BACKGROUND: Whether a hypoplastic transverse arch will grow after successful coarctectomy remains controversial. METHODS: We studied 15 coarctation specimens with hypoplastic transverse arch. Eight patients were less than 1 month old and 7 were between 1 and 3 months. The diameter and length of the various segments of the aortic arch were measured. The number of elastin lamellae was determined histologically. Collagen density was quantified with a microdensitophotometer. Using immunohistochemistry, we determined alpha-actin-positive smooth muscle cells in the media of the ascending aorta and the hypoplastic transverse arch. RESULTS: Despite a hypoplastic transverse arch, the ascending and descending aorta grew. The absolute number of elastin lamellae in the hypoplastic transverse arch was low, but when expressed as a ratio versus its diameter, this number was high (p < 0.05). Collagen density showed high absolute values in the descending aorta. In the older group, 4 of 7 showed no staining for alpha-actin in the hypoplastic transverse arch, whereas under 1 month of age, only 2 of 8 cases were negative. CONCLUSIONS: The hypoplastic transverse arch is characterized by a relatively high number of elastin lamellae. Fewer alpha-actin-positive cells in the hypoplastic transverse arch occur in older specimens, which could indicate a diminished potential growth.

Actins↗
PubMed1997

Morphologic features of the normal aortic arch in neonates, infants, and children pertinent to growth.

BACKGROUND: The aorta in newborns rapidly adapts by growth to postnatal circulatory conditions. The question arises what structural features are associated with growth and whether differences occur between the various segments. METHODS: Nineteen specimens have been studied: seven from babies less than 1 month, seven from 1 month to 1 year, and five from 1 to 4 years. In each baby the diameter of the aortic segments and its branches were measured. Histologically the number of elastin lamellae was counted, and furthermore, collagen density was quantified at several measurement sites. RESULTS: The diameter of each segment increases rapidly after birth and more so than that of the descending aorta, except for the brachiocephalic artery and its branches and the left common carotid artery, albeit not at the same rate. The ascending aorta is the only segment that shows a decrease in the ratio of elastin lamellae to diameter. Collagen density was always highest in the descending aorta. CONCLUSIONS: These observations show that postnatal growth of the thoracic aorta is associated with distinct structural remodeling soon after birth; these observations are of clinical relevance in case of aortic arch abnormalities.

Aorta, Thoracic↗
PubMed1996

Simplified physiological pacing after cardiac surgery.

Temporary pacing wires are routinely placed at the end of cardiac surgery. These pacing wires are helpful in maintaining patients with postoperative bradycardias, and physiological pacing is also more desirable in critically ill patients. We herein report our simplified procedure for atrial pacing. This technique uses commercially available intravenous pacing catheters. The catheter is passed through the skin, and its tip is placed at the pericardial oblique sinus just between the right and left pulmonary veins. Atrial pacing is then initiated with a temporary pulse generator. This procedure is simple and effective for patients undergoing cardiac surgery. We also report two clinical cases that satisfactorily underwent atrial pacing using this procedure.

Adult↗
PubMed1995

Nature of coarctation in hypoplastic left heart syndrome.

The study was designed to establish the underlying pathology of aortic coarctation in hypoplastic left heart syndrome. Aortic coarctation in patients with hypoplastic left heart syndrome is a significant problem when a Norwood procedure or heart transplantation is performed. Previous reports have claimed that the obstruction was merely a branch-point phenomenon and that ductal tissue was absent. Five heart specimens with hypoplastic left heart syndrome and aortic coarctation were examined histologically. The distal segment of the aortic arch, together with the arterial duct, were dissected and processed en bloc. The blocks were sectioned parallel to the longitudinal axis of the aortic arch. In 4 hearts the coarctation was in the preductal position. Ductal tissue encircled the aortic lumen and extended into the aorta both proximally and distally from the ductal orifice. The fifth case showed medial thickening of the aortic wall in the preductal position, but without ductal tissue. The arterial duct showed histologic characteristics of persistent patency. Our observations suggest that aortic coarctation in the preductal position in hypoplastic left heart syndrome is caused by the extension of ductal tissue. The findings may have an impact on clinical strategies for hypoplastic left heart syndrome.

Angioplasty, Balloon↗
PubMed1993

Long-term follow up of ventricular endocardial pacing leads. Complications, electrical performance, and longevity of 561 right ventricular leads.

Five hundred and sixty-one endocardial pacing leads implanted in the right ventricle of 502 patients between 1971 and 1990 were followed for up to 17 years regarding their complications, stimulation threshold behavior, and overall longevity. Lead tip dislodgment occurred in 16 leads (2.9%), in 14 of which dislodgement occurred within 2 months after implantation. The incidence of dislodgement was significantly smaller in tined leads than in nontined leads. Lead conductor fracture occurred in 19 leads (3.4%), in 15 of which fracture occurred within 5 years after implantation. Two particular sites of lead fracture were identified; i.e., one within the pacemaker pocket and the other at a particular point in the subclavian vein between the clavicle and the first rib. Fixation ligature in the former site and the venopuncture point for lead insertion in the latter site are thought to be related to lead fracture. Other complications included insulator break in 3 leads (0.5%), exit block in 7 leads (1.2%), and poor sensing in 2 leads (0.4%). The cumulative survival of leads was 94.1 +/- 2.7% (mean +/- 95% confidence interval) at 5 years, 86.3 +/- 6.3% at 10 years, and 74.2 +/- 14.0% at 15 years after implantation. The minimal stimulation threshold, lead impedance and R wave amplitude were all found to be stable for up to 10 years, and there were no tendencies toward higher stimulation threshold during the observation period of this study.

Electrodes, Implanted↗
PubMed1992

A case report of purulent pericarditis with cardiac tamponade: echocardiographic findings.

A five year old girl with cardiac tamponade due to purulent pericarditis caused by Staphylococcus aureus was treated successfully with a combination therapy of appropriate antibiotics and surgical open drainage. Right atrial collapse was observed during early systole using two-dimensional echocardiography. This case illustrated the usefulness of echocardiography for early detection and treatment of cardiac tamponade in pediatric patients.

Cardiac Tamponade↗
PubMed1992

[Surgical treatments of nonconfluent pulmonary arteries with congenital cardiac defects].

Pulmonary artery angioplasty or reconstruction was performed in seven patients with nonconfluent pulmonary arteries and congenital cardiac defects. Age of these patients were ranged from 6 months to 41 years old. Five of them had pulmonary truncal atresia and complex cardiac anomalies. Two of these five patients demonstrated nonconfluent pulmonary arteries due to deformities at ductal insertion of pulmonary arteries. Three patients had had previous systemic to pulmonary artery shunt operations which caused pulmonary artery distortions. Other two patients had intrapulmonary arterial obstructions due to pulmonary artery thrombosis. Patch pulmonary artery plasty was carried out in three patients, dilatation of severe stenotic pulmonary artery was done in one patient simultaneously with pulmonary valvotomy. Central shunt operation was added in one patient with the pulmonary artery which was unable to be reconstructed. Last two patients underwent intrapulmonary artery reconstruction with the rolled pericardial graft. Hospital death occurred in one patient with unproperly increased pulmonary blood flow by central shunt. Average follow-up period of these six survivors after operation was 1.4 +/- 0.8 years. As definite repairs, two patients had Fontan operation, two patients had right ventricle to pulmonary artery reconstruction. And remaining two patients are still to be followed until sufficient growth of pulmonary artery suitable for Fontan operation.

Adolescent↗
PubMed1989

[Is left ventricular venting necessary in open heart surgery?].

In this study we intended to clarify the benefits of left ventricular venting by comparing the surgical results and clinical courses of 19 adult patients who underwent open heart procedures with venting and those of 44 adult patients who had open heart procedures without venting. All of the patients of both groups underwent operations for acquired heart diseases. The hospital mortality was 10.5% in the vent group and 2.3% in the no-vent group (NS). None of the deaths occurred due to the postoperative low output syndrome in either group. The incidence of spontaneous defibrillation was not different in the two groups, and no patients required postoperative IABP support in either group. The number of patients who needed catecholamine infusion for longer than 24 hours postoperatively were not statistically different in the two groups, and incidence of ventricular arrhythmias was not different in the two groups. The cardiac index determined 6 hours postoperatively was significantly higher in the no-vent group. The left atrial pressure in the no-vent group did not exceed 10 mmHg during cardiopulmonary bypass, if the central venous pressure was maintained below 7 mmHg. It was suggested that distension of the left ventricle and myocardial injuries do not occur during cardiopulmonary bypass without left ventricular venting, provided the central venous pressure is maintained below 6 or 7 mmHg.

Adult↗