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Biomedical subjects

H Ohzeki

Publications and source records attributed to H Ohzeki.

At least 19 recordsLinked to original sources
PubMed2000

Transcription modulation by a rat nuclear scaffold protein, P130, and a rat highly repetitive DNA component or various types of animal and plant matrix or scaffold attachment regions.

The XmnI fragment, a highly repetitive DNA component, and animal and plant matrix or scaffold attachment region (MAR/SAR) were examined for similarity in interaction with nuclear scaffold. As the XmnI fragment bound a 130 kDa scaffold protein (P130) in vitro, various types of MAR/SAR fragments could bind 130 and 123 kDa scaffold proteins. The native XmnI and MAR/SAR fragments clearly augmented SV40 promoter-mediated luciferase gene transcription following transient transfection of recombinant plasmids into various types of recipient cells. In contrast, the XmnI fragment methylated at the cytosine base of the unique HindIII site, and a synthetic variant DNA deficient in base unpairing characteristic of MAR/SAR, could neither bind P130 nor augment this transcription. These two types of genomic regions appeared to have similar properties of interaction with nuclear scaffold, by which the activity of appropriately positioned promoter can be modulated.

Animals↗
PubMed2000

Changes in graft flow pattern from the descending aorta due to intraaortic balloon pump.

During surgery for lung cancer in a patient who had undergone coronary artery bypass grafting through the descending aorta by left thoracotomy, we measured graft bypass blood flow from the descending aorta under intraaortic balloon pump (IABP) assistance. Under IABP assistance, the diastolic waveform changed to a spiky pattern with a sharp drop in blood flow of approximately 16% compared to that without IABP assistance. We report changes in graft flow pattern during IABP assistance when the graft is placed from the descending aorta.

Aorta, Thoracic↗
PubMed1999

The effect of fibrin glue on inhibition of pericardial adhesions.

The effect of fibrin glue on inhibition of pericardial adhesions was tested using 26 beagle dogs. Dacron patches were sutured to the heart and tincture of iodine was applied to promote adhesions. Fibrin glue (3 ml) was sprayed over the patches in 15 dogs (test group), and was not separated in the remaining 11 dogs (control group). All animals in the test group had minimal adhesions between the pericardium and the epicardium or patched region, and an accumulation of gelatinous material was found in the subpericardial space. Marked fibrosis and a poor demarcation of the subpericardial space were found in the control group. The adhesion score and the visibility of coronary anatomy in the test group were significantly better than in the control group. The tension strength in the test group was significantly less than in the control group. We concluded, therefore, that fibrin glue may also be useful as an adhesion inhibitor.

Animals↗
PubMed1999

Biocompatibility of a silicone-coated polypropylene hollow fiber oxygenator in an in vitro model.

BACKGROUND: A silicone-coated microporous hollow-fiber membrane oxygenator has been developed to prevent plasma leakage during long-term use. The objective of this study was to evaluate the biocompatibility of the oxygenator. METHODS: A silicone-coated oxygenator was compared with an uncoated oxygenator in an in vitro model of cardiopulmonary bypass. Simulated circulation was maintained for 6 h at 37 degrees C. RESULTS: Platelet counts decreased significantly (p < 0.05) and leukocyte counts tended to decline; however, the differences between groups were not significant. Concentrations of C3a increased significantly in both groups (p < 0.05), but levels were significantly less in the silicone-coated oxygenator (p = 0.008). In contrast, concentrations of C4a, beta-thromboglobulin, and granulocyte elastase increased significantly (p < 0.05), but the differences between groups were not significant. CONCLUSIONS: Silicone coating over a microporous hollow-fiber membrane may improve biocompatibility by reducing C3a activation.

Coated Materials, Biocompatible↗
PubMed1999

Surgical management of cardiovascular lesions caused by systemic inflammatory diseases.

BACKGROUND: The surgical treatment of cardiovascular disorders caused by inflammatory diseases presents many difficulties, including suture detachment and progression of vascular lesions. We here report the various surgical procedures used to treat these disorders and their long-term outcomes. METHODS: We operated on 14 patients: eight with Takayasu's disease, three with systemic lupus erythematosus, two with rheumatoid arthritis, and one with Behçet's disease. Patients were divided into three groups as follows; patients (n=7) requiring aortic valve replacement; patients (n = 4) requiring reconstruction of the coronary artery; and patients (n = 3) requiring aortic aneurysm repair. RESULTS: There were no early or late deaths in the postoperative follow-up period of 70 +/- 40 months, but there was one operative death. Three patients received postoperative steroids due to progression of the inflammation. However, there were no major complications such as valve detachment, pseudoaneurysmal formation, or occlusion of the bypass conduit. CONCLUSIONS: We conclude that it is crucial to reduce inflammation pre- and postoperatively, to reinforce the suture line, and to carefully select the operative procedures when treating cardiovascular disorders caused by inflammatory diseases.

Adolescent↗
PubMed1999

Special cerebral perfusion in surgery for the ruptured thoracic aortic aneurysm.

BACKGROUND: For surgical treatment of the ruptured thoracic aortic aneurysm (TAA), it is important to control bleeding and to protect the brain, spinal cord, and myocardium. We have developed and performed a new procedure on 6 patients with a ruptured TAA, a true aneurysm in 3 patients and a type A dissection in the other 3. METHOD: Cardiopulmonary bypass is installed with cannulations to the iliac artery and vein and to the common carotid arteries on both sides of the neck before the sternum is divided. For control of bleeding, venous drainage is accelerated, whereas cerebral perfusion is maintained via the carotid arteries. After insertion of the occlusion catheters into the descending aorta and the left subclavian artery following the aortotomy, the bypass flow to the iliac artery is increased. RESULTS: The arch replacement was performed in 4 patients and hemiarch replacement in two. Five patients are alive without neurologic deficits; one patient died of multi-organ failure on the 24th postoperative day. CONCLUSIONS: We conclude that our procedure may be advantageous for patients with a ruptured TAA, a large retrosternal aneurysm, or reoperation of the thoracic aorta.

Aged↗
PubMed1999

Respiratory insufficiency caused by an aneurysm with multiple vascular lesions.

A 71-year-old woman, who presented tracheobronchial obstruction caused by a thoracic aortic aneurysm, was admitted to our institution. Although she had multiple cerebral infarctions, old myocardial infarction, bilateral iliofemoral atherosclerotic lesions with abdominal aortic aneurysm, and superior vena cava syndrome, aneurysmectomy was undertaken in order to rescue her from respiratory insufficiency. The operation successfully relieved her of exertional dyspnea and dysphagia.

Aged↗
PubMed1999

"Tail sign" associated with microembolic signals.

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound (TCD) can detect circulating microembolic signals (MES). We focused our attention on tail signs (TS), a signal associated with MES that appeared as a small reversal signal after MES on the high time resolution spectral display. We examined MES and artifacts in an animal study to determine whether TS were specific changes associated with MES and investigated the characteristics of TS in both animal and clinical studies. METHODS: In an animal study, adult pigs with venoarterial extracorporeal membrane oxygenation and minimal anticoagulation therapy were used as a model for cerebral embolism. After performing TCD monitoring with a multigated approach, we did an offline analysis to investigate several parameters concerning MES and TS. We also examined TS in patients in a clinical study. RESULTS: From a total of 362 MES investigated in the animal study, 72.9% were followed by TS. We could not find any TS associated with artifacts. The time delay between TS and MES was negatively correlated with the velocity of MES. MES almost always appeared first in the proximal channel, whereas TS conversely appeared first in the distal channel. In the clinical study, we were also able to observe TS associated with MES. CONCLUSIONS: TS may represent emboli passing down a branch vessel or twisted downstream vessel. TS are specific for MES and can be used as another criterion for MES identification.

Adult↗
PubMed1998

Involvement of DNA methylation in binding of a highly repetitive DNA component to nuclear scaffold proteins from rat liver.

Experimental reduction of the amount of CpG methylation in a highly repetitive DNA component was achieved by growth of Ac2F cells in the presence of 5-aza-2'-deoxycytidine or procainamide, as judged by the results of methyl-sensitive restriction endonuclease digestion and colony hybridization. Modification of genomic DNA with these DNA methylation inhibitors increased the release of 370-bp highly repetitive DNA from rat chromosomal DNA by HindIII digestion. This result indicated that highly repetitive DNA components in the nuclear scaffold fraction are hypermethylated. On the other hand, methylated DNA was used for southwestern analysis to investigate the protein(s) which bind specifically to the DNA in the nuclear scaffold fraction. The introduction of additional methylated cytosines within a highly repetitive DNA component affected the binding of DNA to the nuclear scaffold proteins. Thus, cytosine methylation may be involved in the regulation of gene expression and construction of the higher-order structure of chromatin.

Animals↗
PubMed1998

Involvement of phosphorylation in binding of nuclear scaffold proteins from rat liver to a highly repetitive DNA component.

The results of our previous work [Hibino et al., Biochim. Biophys. Acta 1174 (1993) 162-170] suggested that a highly repetitive DNA component facilitates bending of the helix axis to be recognized by the nuclear scaffold proteins from rat liver, P123 and P130. In the present experiment, it was shown that binding of these proteins to such a repetitive DNA component from rat liver nuclei (370-bp XmnI fragment) is based on a cooperative mode of interaction, although the binding activity of P130 is much higher than that of P123. The immunoblot analysis with anti-phosphoamino acid antibodies suggested that phosphorylation of serine and threonine residues occurs on P123 and P130, but also of tyrosine residue(s) on P130. The phosphatase assay showed that phosphoryl groups on these proteins may be involved in altering the DNA binding activities of the proteins. Thus, the results in the present study imply that phosphorylation of a nuclear scaffold protein in addition to the degree of bending of the DNA helix axis plays an important role in anchoring chromatin to the nuclear scaffold and in construction of a higher-order chromatin structure.

Animals↗
PubMed1998

Successful surgery for an acute type A aortic dissection following repair of a descending thoracic aortic aneurysm.

Acute type A aortic dissection in the presence of a previously repaired atherosclerotic descending thoracic aortic aneurysm is rarely reported. We experienced a patient who underwent an ascending aortic replacement with reconstruction of the aortic arch 16 months after repair of a descending thoracic aortic aneurysm. We succeeded in the redo operation with comprehensive techniques involving selective cerebral perfusion, deep hypothermia, early antegrade systemic circulation for cerebral protection, and femoro-femoral bypass with occlusion of the descending aorta for lower systemic perfusion as well as renal perfusion. The patient recovered and is doing well one year after the redo operation.

Acute Disease↗
PubMed1998

Left atrial ball thrombi without mitral valve disease treated by surgical removal.

We describe two patients with free-floating left atrial ball thrombi with no evidence of cardiac disease except atrial fibrillation. One patient had experienced an embolic stroke, and the second patient had a history of stroke and peripheral thromboembolism. In each patient, the thrombi, which were not visible on transthoracic echocardiography, were detected by transesophageal echocardiography. Each patient underwent successful surgical removal using cardiopulmonary bypass.

Aged↗
PubMed1998

Successful removal of massive cardiac neurilemoma with cardiopulmonary bypass.

A 46-year-old woman was referred to our hospital because of cardiac enlargement seen on a chest radiograph. Imaging studies showed a massive intrapericardial tumor with a size of 12x8x7 cm. Tumor dissection included inspection of the inner aspect of the superior vena cava with use of cardiopulmonary bypass, because the mass was tightly adherent to both superior vena cava and right atrium. The pathologic diagnosis was neurilemoma.

Cardiopulmonary Bypass↗
PubMed1998

Surgery for giant popliteal artery aneurysm with a modified Sims' position.

A 73-year-old man with a giant popliteal artery aneurysm extending from the mid-thigh to the popliteal fossa underwent exclusion, bypass, and obliterative endoaneurysmorrhaphy while in a modified Sims' position. The use of this position allowed for exposure of the saphenous vein and the entire popliteal artery in the same operative field. No muscle division was required. Moreover, this position provided easy access to the superficial femoral and distal below-knee popliteal arteries.

Aged↗
PubMed1998

Complete intercostal artery reimplantation using a method of aneurysmoplasty.

We report the case of a 58-year-old woman who underwent repair of a chronic dissecting thoracoabdominal aortic aneurysm. Using a method of aneurysmoplasty under normothermic cardiopulmonary bypass, all intercostal arteries were quickly reperfused, and the spinal cord ischemic time was minimized. No neurological deficits developed in our patient using this method.

Aortic Dissection↗
PubMed1997

Acute acalculous cholecystitis after cardiovascular surgery.

The development of acute acalculous cholecystitis (AAC) after cardiovascular surgery is an infrequent but devastating complication, the etiology and management of which remains controversial. To evaluate the etiology, treatment, and outcome of patients with AAC, the cases of six patients encountered within an 8-year period who developed AAC after cardiovascular surgery requiring cardiopulmonary bypass (CPB) were reviewed. Atherosclerotic risk factors including diabetes, hyperlipidemia, and smoking were evident in five patients, three of whom had a history of stroke or arteriosclerosis obliterans, while low cardiac output was recognized in three. Percutaneous transhepatic cholecystostomy was performed in five patients, and another required cholecystectomy for peritonitis due to gangrene of the gallbladder. Two patients died of respiratory failure and sepsis after 15 and 82 days of percutaneous drainage, respectively; however, the four survivors had an excellent outcome without any biliary tract disease during a mean follow-up period of 5.3 years. In conclusion, AAC after cardiovascular surgery may result from hypoperfusion of the gallbladder due to various factors including CPB, visceral atherosclerosis, and low cardiac output. We advocate early percutaneous cholecystostomy for patients without peritonitis, while early cholecystectomy is indicated for those with peritonitis.

Acute Disease↗
PubMed1997

Surgical treatment of aortic root abscess with damage of the mitral valve apparatus.

A 35-year-old man with an aortic root abscess successfully underwent aortic valve replacement and mitral valve repair using a prosthetic valve with a skirt which was secured to the sewing cuff. This is a useful technique for reinforcement of a fragile annulus and prevention of annular detachment. A further useful technique is to infuse normal saline from a Foley catheter inserted into the aortic root to estimate mitral valve coaptation.

Abscess↗