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Biomedical subjects

S Kawada

Publications and source records attributed to S Kawada.

At least 109 records · Page 6Linked to original sources
PubMed1995

Combined cisternal drainage and intrathecal urokinase injection therapy for prevention of vasospasm in patients with aneurysmal subarachnoid hemorrhage.

The effect of cisternal drainage and intrathecal urokinase injection in preventing symptomatic vasospasm (SVS) after aneurysmal subarachnoid hemorrhage was studied in 60 patients with uniform background (Hunt & Kosnik grade III, younger than 70 yrs, undergoing surgery within 72 hrs after hemorrhage). The incidence of permanent neurological deficits caused by vasospasm was 5/16 without cisternal drainage, 5/34 with drainage alone, and 1/10 with drainage and urokinase injection. Analysis of patients without postoperative cisternal drainage showed the amount of subarachnoid clot on the initial computed tomographic scan was closely related to the occurrence of SVS (p < 0.05, unpaired t test). Analysis of patients with cisternal drainage showed the amount of bloody cerebrospinal fluid (CSF) drained during the 10 days after surgery and the duration of drainage placement were critical in preventing vasospasm (p < 0.05, unpaired t test). Greater CSF drainage significantly reduced the incidence of permanent neurological deficits caused by vasospasm (p < 0.01, chi 2), but significantly increased the incidence of hydrocephalus requiring shunt procedures (p < 0.01, chi 2). Urokinase injection via cisternal drainage achieved a further reduction in the occurrence of SVS. Intrathecal thrombolytic therapy after aneurysmal surgery is an effective method for SVS prophylaxis, and CSF drainage (> 1500 ml for 10 days) enhances the effect.

Brain↗
PubMed1995

Terpentecin and ECT4B, new family of topoisomerase II targeting antitumor antibiotics produced by Streptomyces: producing organism, fermentation and large scale purification.

Terpentecin and UCT4B are new family of antitumor antibiotics with topoisomerase II mediated DNA cleavage activity. Based on the taxonomic studies, the producing strain S-464 was identified as Streptomyces sp. This strain is different from Kitasatosporia griseola which had been identified as the terpentecin-producing strain in 1988. Fermentation studies showed that natural nitrogen sources supported higher titer of terpentecin, and the synthetic medium with inorganic nitrogen sources supported selective production of UCT4B. An improved isolation method was developed for the large scale purification of terpentecin.

Antibiotics, Antineoplastic↗
PubMed1995

[A case of acquired von Willebrand disease due to pulmonary stenosis after Jatene's operation].

The case of a 9-year-old girl with pulmonary stenosis complicated by acquired bleeding tendency after Jatene's operation is reported. Coagulation study revealed that platelet count and von Willebrand factor were reduced. Catheterization study revealed severe pulmonary stenosis, the pressure gradient between the right ventricle (RV) and pulmonary artery (PA) being 190 mmHg. A link between pulmonary stenosis and bleeding tendency was suggested and the patient was diagnosed as having acquired von Willebrand disease due to activated platelet/von Willebrand factor interactions enhanced by "shear stress" at the site of pulmonary stenosis. Right ventricular outflow reconstruction was done when she was 9 years-old. Due to a protocol based on the results of the challenge test that we instituted to determine the efficacy and effective duration of blood derivatives and hemostatic agents, perioperative massive bleeding was avoided. Bleeding tendency disappeared and coagulation study findings normalized with correction of the abnormal hemodynamic state.

Child↗
PubMed1994

Combined anteroposterior tibial perforator-based flap with a vascularized deep peroneal nerve for repair of facial defect.

To reconstruct deep facial defects involving the facial nerves after resection of a malignant parotid tumor, a flap with a vascularized nerve graft is often required because the lesion is often accompanied by poor vascularization as a result of preoperative or postoperative radiotherapy. These defects can be repaired in one stage with a combined anteroposterior tibial perforator-based flap including a vascularized deep peroneal nerve graft. This combined flap can include the long vascularized deep peroneal nerve, and augumentation of the lower leg flaps is possible by additional vascular anastomosis of branches of the source vessel of the neighboring flap, the "mosaic" principle.

Aged↗
PubMed1994

Different modes of cell-killing action between DNA topoisomerase I and II inhibitors revealed by kinetic analysis.

We compared the modes of cell-killing by DNA topoisomerase I and II inhibitors. The effects of camptothecin (CPT), KT-6528 and UCE6 upon colony formation by inhibiting DNA topoisomerase I, and of etoposide (VP-16), teniposide, amsacrine and UCT4-A as inhibitors of DNA topoisomerase II were analyzed based upon a kinetic method that distinguishes between cell cycle phase-specific and -nonspecific agents. Human colorectal cancer WiDr cells were exposed to several concentrations of each agent for various periods and 90%-inhibitory concentrations (IC90) at each time were determined by means of a clonogenic assay. When exposure times and corresponding IC90s were plotted on a log-log scale, all inhibitors of DNA topoisomerase II gave curves including a linear portion with a slope of -1, which is characteristic of cell cycle phase-nonspecific agents. In contrast, the curves for all inhibitors of DNA topoisomerase I had a much steeper slope than -1, which is typical of cell cycle phase-specific agents. In agreement with this finding, the cells were remarkably accumulated in the G2-M phase when exposed to VP-16, but in late S-phase when exposed to CPT as determined by a flow cytometric assay. These results indicated that the two classes of agents kill cells in a quite different manner although they are inhibitors of similar enzymes.

Amsacrine↗
PubMed1994

The effect of stimulating voltage on time characteristics of contraction in cardiomyoplasty.

In cardiomyoplasty (CMP), the strength of a skeletal muscle increases as the stimulating voltage increases. On the other hand, timing of stimulation in CMP is a problem not yet solved. This experiment assessed the relationship between stimulating voltage and time characteristics in the contraction of skeletal muscles. In acute experiments using rabbits, the time required to reach maximal muscle contraction did not change significantly with voltage. In conclusion, stimulation voltage does not affect time characteristics. Thus, the best timing of stimulation in CMP can be assessed independently of voltage.

Animals↗
PubMed1994

Do we really need pulse? Chronic nonpulsatile and pulsatile blood flow: from the exercise response viewpoints.

The response of the body and the blood pump was evaluated in animals with a pulsatile artificial heart (total artificial heart [TAH]) and those with a nonpulsatile artificial heart (nonpulsatile biventricular bypass [NPBVB]) subjected to the same exercise load. The animals used in this study were 5 calves implanted with a pusher-plate type TAH (45-206 days) and 5 calves implanted with a nonpulsatile centrifugal pump (34-99 days). The pre-exercise pump flow rate was 92.1 +/- 8.1 ml/kg/min for the TAH group and 94.8 +/- 9.1 ml/kg/min for the NPBVB group, with no significant difference between the two groups. The workload was administered at a rate of 1.5 mph for 15 min. The artificial heart driving conditions were kept constant throughout the test period. Sequential changes in hemodynamic response and metabolism were determined before, during, and for 30 min after exercise. Both TAH and NPBVB calves showed excellent tolerance of the workload (1.5 mph exercise); in NPBVB calves, oxygen demand was compensated for by an increase in the arteriovenous oxygen difference during exercise; and norepinephrine showed a greater response in the NPBVB group. Based on the results presented, the nonpulsatile pump seems to lend itself to a mechanically driven artificial heart of the complete implantation type because of its small size, high efficiency, and the lack of need for a compliance chamber.

Animals↗
PubMed1994

A miniaturized centrifugal pump for assist circulation.

The newly developed Nikkiso HMS-15 is a miniaturized centrifugal pump. It has an impeller diameter of only 50 mm and a priming volume of only 25 ml. A totally new approach was applied to develop this very small pump. The new pump showed comparable hemolysis with pumps twice as big (e.g., the most widely used cone-shaped centrifugal pump [index of hemolysis, 0.005]). This finding refutes the belief that the pump diameter must be sufficiently large in size. Clinical application for cardiac assist was performed for 48 h without any thrombus formation despite low heparin dosage. Also, the pump showed quite favorable blood trauma when applied as a pump for cardiopulmonary bypass during open heart surgery. The compactness, the high controllability, and the system versatility proved to be very effective for clinical application. This pump is considered very reliable for its highly optimized design.

Aged↗
PubMed1994

[Preliminary clinical results of surgery for type A acute aortic dissections using gelatin-resorcin-formaldehyde glue].

We used gelatin-resorcin-form-aldehyde (GRF) glue to fuse the false lumen of type A acute aortic dissection in four patients. All were operated on within 3-24 hours after onset, and gluing of the two cylinders of the dissecting aorta could be done safely in a short time. Initial intimal tears were located in the transverse aorta in three patients and in the proximal descending aorta in one. Simple transection and end-to-end anastomosis of the ascending aorta was done for the first two cases. But in the last two patients, we resected the intimal tear in the transverse aorta and applied GRF glue to the stump of the aortic arch and to that of the aortic root, followed by graft replacement of the ascending aorta. There were no hospital deaths. But we had to reoperate on one patient five months after the first operation due to potentially residual dissection in the aortic root. GRF glue is a very useful adhesive for acute aortic dissection operations, but further refinement of the operative technique using it is necessary.

Acute Disease↗
PubMed1994

[The surgical treatment of coarctation of the aorta and interruption of the aortic arch in the first three months of life--effectiveness of temporary bypass between the pulmonary artery and the descending aorta].

From February 1987 to January 1994, we operated on 24 patients with coarctation of the aorta (CoA) and 9 patients with interruption of the aortic arch (IAA). A policy of staged repair was followed, consisting of reconstruction of the aortic arch with pulmonary artery banding and ligation of the ductus arteriosus in the first stage and intracardiac repair with pulmonary artery band removal in the second stage. In recent cases an extended aortic arch anastomosis was performed using a heparin-coated "shunt tube" between the pulmonary artery and the descending aorta to maintain blood flow to the lower half of the body during aortic cross-clamping. The use of the shunt increased intraoperative urine output (p < 0.05). This technique may allow patients whose condition is poor to undergo aortoplasty more safely. One patient died. This patient had CoA and total anomalous pulmonary venous return, who underwent a one-stage repair, in violation of our policy (early mortality 3.0%). There were two interim deaths before the second stage repair. At present, 18 patients have undergone staged intracardiac repair, including VSD closure (14 cases), Jatene's procedure (1), Ratelli's procedure (1), Damus-Kaye-Stansel (DKS) procedure (1), total cavo-pulmonary connection (TCPC) + DKS procedure+annuloplasty of a common atrioventricular valve (1). There were two early deaths and one late death following intracardiac repair, all in patients with IAA plus VSD.

Anastomosis, Surgical↗
PubMed1994

[A case of successful surgical treatment for coarctation of the aorta associated with ruptured cerebral aneurysm].

We present a case of a sixteen year old boy with coarctation of the aorta who suffered ruptured cerebral aneurysm. Both cerebral and aortic lesions were successfully corrected. He complained of sudden headache and nausea. Subarachnoid hemorrhage was diagnosed by computed tomography of the head. Cerebroangiography demonstrated coarctation of the aorta. Clipping of cerebral aneurysm was done at first, then three months later, complete resection of the aortic coarctation and artificial graft replacement was done by using femoral veno-arterial cardiopulmonary bypass.

Adolescent↗
PubMed1994

[A case of partial atrioventricular canal with discrete subvalvular aortic stenosis worsened 3 years after the replacement of the mitral valve].

The extension of the left ventricular outflow tract is provoked by a partial atrioventricular canal, and is easy to cause stenosis after a radical operation and/or a replacement of the left atrioventricular valve because of its anatomical structure. This report shows a case of a partial atrioventricular canal with a discrete subvalvular aortic stenosis which was worsened three years after the replacement of mitral valve. In this case the left ventricular outflow tract obstruction (LVOTO) had been found before the replacement of mitral valve but it was kept observing without surgical treatment because the degree was judged slight. Subvalvular aortic stenosis was worsened three years after the replacement. It was suspected that the stenosis developed because of the proliferation of heterologous tissue by a turbulent flow of a site of stenosis. For this diagnosis, the transesophageal echocardiography was very effective, and in this case the cause of LVOTO is uncertain, so a careful observation is necessary for it.

Adult↗
PubMed1994

[A concomitant operation of Damus-Kaye-Stansel procedure, atrioventricular valvuloplasty and total cavopulmonary connection].

A 2-year-old girl with single ventricle and coarctation of aorta, who received subclavian flap aortoplasty and pulmonary artery banding at 30 days of age, developed subaortic stenosis and atrioventricular valve regurgitation. At the age of 2 years and 10 months, physiologic correction with atrioventricular valvuloplasty, Damus-Kaye-Stansel procedure, and total cavopulmonary connection were performed concomitantly. She showed uneventful convalescence, and postoperative cardiac catheterization revealed trivial atrioventricular valve regurgitation with a mild pressure gradient between the left ventricle and aorta.

Anastomosis, Surgical↗
PubMed1994

[Removal of infected total pacemaker system under extracorporeal circulation--a case report and review of the Japanese literature].

A 35-year-old male with sick sinus syndrome was complicated with recurrent local infection at the site of the generator pocket associate with a retained pacemaker lead, followed by septicemia presenting with Staphylococcus aureus. Several attempts to remove the lead via the implantation vein by direct traction were performed unsuccessfully because the leads were strongly adhered to the trabecula of the right ventricle. Repeated debridement employing antibiotic therapy was ineffective. As a last resort, we finally operated under extracorporeal circulation (ECC) 24 months after the first implantation and 22 months after initiation of the local infectious episode. As we found it difficult to remove the leads by traction even under direct vision, we used the vinyl chloride tube, which is a part of the ECC circuit, as a sheath for applying countertraction around the lead tip to prevent the myocardial wall from being torn and extracted together with the lead tip. The lead was removed successfully and a new epicardial lead was implanted. The postoperative course uneventful and no recurrence has occurred after 1 year. In reviewing the Japanese literature, 10 case, operated on under ECC to remove the infected retained leads, were described in detail. Among them, eight cases had undergone previous debridement including removal of the generator and the subcutaneous portion of the lead. It is clear that removal of all of the pacemaker system is necessary for eradication of infection. Adhesion of the lead to the wall is firm. Only one case besides ours succeeded in having its lead removed without requiring incision of the tissue around the lead tip.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Redo operations for dissecting aortic aneurysm].

We reoperated twenty-four times upon twenty cases of dissecting aortic aneurysm since 1983. Nine of them (45%) were Marfan patients. Reoperations on the same part of the aorta as the prior procedure was done 15 times upon 13 cases with six hospital deaths (40%). Reoperations on the different part of the aorta from the prior operation was done 9 times on 9 cases with one hospital death (11%). Over all hospital mortality rate was 29%. The hospital mortality rate for Marfan patients (8%) was significantly better than that for non-Marfan patients (50%).

Adult↗
PubMed1993

Assisted circulation using cardiomyoplasty together with aortomyoplasty.

Both dynamic cardiomyoplasty and counterpulsation by the synchronous paced contraction of skeletal muscles in aortomyoplasty can improve ventricular function. The goal of this study was to clarify the effect of cardiomyoplasty combined with aortomyoplasty on cardiac dysfunction in dogs. The percentage of increase in various hemodynamic parameters was calculated during assisted and unassisted cardiac cycles and was compared for three groups: cardiomyoplasty only (Group A), aortomyoplasty only (Group B), and both methods combined (Group C). In Group A, the left ventricular pressure (LVP), systolic aortic pressure (systolic AoP), and dp/dt of LVP (LV dp/dt) increased significantly; the diastolic aortic pressure (diastolic AoP) did not change; and the endocardial viability ration (EVR) decreased during assisted cardiac cycles. In Group B, the diastolic AoP and EVR were improved significantly, but the LVP, LV dp/dt, and systolic AoP were unchanged during assisted cardiac cycles. In contrast to Groups A and B, all parameters were improved in Group C during assisted cardiac cycles. Cardiac assistance using cardiomyoplasty together with aortomyoplasty was more effective than either procedure used alone.

Animals↗