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Biomedical subjects

H Iida

Publications and source records attributed to H Iida.

At least 199 records · Page 11Linked to original sources
PubMed1997

[The differences of the cerebral and spinal vessels in sensitivity to PaCO2 and vasoconstrictors].

We investigated the differences in the response to arterial CO2 tension and vasoconstrictors between the cerebral and spinal vasculatures using cranial and spinal window technique which provided the direct observation of pial vessels. Pentobarbital anesthetized dogs (n = 18) (CO2 tension; n = 6 and vasoconstrictor; n = 12) were instrumented for measurement of pial vessel diameters by intravital microscopy in the cranial and spinal window preparation simultaneously. We achieved hypocarbia (20-25 mmHg) followed by adjusting CO2 levels for normocarbia (35-40 mmHg) and for hypercarbia (55-60 mmHg) using CO2 gas addition. After obtaining the desired PaCO2, the measurements were made. In the next experiment, we administered 2 different concentrations of epinephrine or phenylephrine solutions (1:2 x 10(6), 1:2 x 10(5)) through the window, and the measurement was made sequentially. The response of cerebral and spinal vasculature to change in PaCO2 was almost similar. Topical application of both drugs produced a significant constriction of spinal pial arterioles compared with the cerebral ones, while epinephrine but not phenylephrine constricted cerebral pial venules compared with spinal ones. These results suggest that the responses to vasoconstrictor of cerebral and spinal pial vessels are not similar, and high sensitivity of spinal arterioles to vasoconstrictors may possibly contribute to a risk of ischemic damage of the spinal cord.

Animals↗
PubMed1997

[Beneficial effects of continuous hemodiafiltration after cardiac surgery in patients with chronic renal failure].

From December 1993 to June 1996, fourteen patients with chronic renal failure (CRF) were underwent cardiac surgery. Thirteen of them had coronary artery bypass grafting (CABG) and one patient had aortic valve replacement. We employed continuous hemodiafiltration (CHDF) with or without peritoneal dialysis in eleven cases in the early postoperative course of open heart surgery. In these cases, the usefulness of CHDF were examined. CHDF was started after 16.9 +/- 13.7 hours of surgery, and continued for 31.9 +/- 18.0 hours. We adjusted blood flow as 80 ml/min, perfusate flow of hemofilter as 500 ml/hr, and the activated clotting time (ACT) as 150-200 seconds with heparin or nafamostat mesilate. No hemorrhagic tendency was observed. Mean serum creatinine level before and after 24 hours of CHDF was 5.6 +/- 2.2 and 5.6 +/- 2.1 mg/dl respectively, and it was not elevated. The average removal volume was 2,223 +/- 1,256 ml for the first 24 hours, and pulmonary wedge pressure was decreased from 9.0 +/- 2.3 to 6.4 +/- 3.0 mmHg (p < 0.05). However, there was no significant change at cardiac output before and after CHDF. Total dose of dopamine and dobutamine were unchanged. No significant change were noted at systemic vascular resistance and pulmonary vascular resistance. We conclude that CHDF allows an adequate removal of fluid and waste products without deleterious effects on hemodynamics even in patients after cardiac surgery. CHDF is a safe and effective alternative in patients with CRF after cardiac surgery.

Aged↗
PubMed1997

[Evaluation of coronary artery bypass grafts with magnetic resonance imaging].

Currently, the efficacy of magnetic resonance imaging (MRI) for evaluating coronary artery disease has been reported. In this study, we have evaluated the usefulness and the problems of MRI for evaluating the patency of coronary artery bypass grafts. Thirty-five patients who received coronary artery bypass grafting (CABG) were evaluated by using MRI for determining the graft patency compared with conventional coronary angiography. There were 30 men and 5 women. The mean age was 61.2 years (range 45 to 75). The 35 patients had a total of 92 grafts (28 internal thoracic artery, 7 gastroeploic artery and 57 saphenous vein grafts). Magnetic resonance coronary angiogram (MRCA) was performed with SIGNA HORIZON 1.5 T (GE Inc.) by using 2D-FASTCARD sequence. All patients underwent imaging in the transverse and coronal planes, most had imaging in the sagittal plane, and a few had in the oblique plane. By using MRCA, 82 of 90 grafts were diagnosed correctly as patent, and 1 of 2 grafts were diagnosed correctly as occluded. Thirty-four of 40 LAD grafts (85%), 20 of 22 RCA grafts (91%) and 29 of 30 Cx grafts (97%) were correctly evaluated. The efficacy of MRCA for evaluating the patency of coronary artery bypass grafts was recognized. But the sternal wire (stainless steel) and hemoclip interfere with the interpretation and reduce the sensitivity. Higher sensitivity may be obtained by changing the material of the sternal wires and hemoclips at coronary surgery.

Aged↗
PubMed1997

[Urgent coronary reoperation under the beating heart via the left thoracotomy].

An 80-year-old female, who had received coronary artery bypass grafting (CABG) 12 years ago was admitted to our hospital because of unstable angina. The vein grafts to the left anterior descending artery (LAD) and circumflex artery (Cx) were both occluded. Chest computerized tomography showed a severely calcified aorta. An intra-aortic balloon pump was inserted and an urgent reoperation was performed. The patient was positioned for an anterolateral left thoracotomy. The chest was entered through the forth intercostal space. The pericardium was opened parallel to the phrenic nerve. Femorofemoral bypass was instituted. Anastomosis of the saphenous vein graft and the diagonal branch and anastomosis of a second saphenous vein to the old SVG just proximal to the anastomotic site of Cx were performed under a beating heart. Proximal anastomosis of the two saphenous veins and the left subclavian artery was then performed. The patient had an uncomplicated postoperative recovery. A postoperative angiogram showed that the new SVG anastomosed to the diagonal branch was patent while the other new SVG anastomosed to the old SVG/Cx was occluded. The patient was discharged and is now free from angina.

Aged↗
PubMed1997

Regional cerebral blood flow measurement with iodine-123-IMP autoradiography: normal values, reproducibility and sensitivity to hypoperfusion.

UNLABELLED: We recently proposed a simplified technique for measuring regional cerebral blood flow (rCBF) using the [123I]N-isopropyl-p-iodoamphetamine (IMP) autoradiographic (ARG) method with SPECT (the IMP-ARG method). We examined normal values of rCBF and the reproducibility and sensitivity to hypoperfusion in stroke patients using this method. METHODS: By using a standard arterial input, a single static scan, a fixed distribution volume (Vd) and one-point arterial blood sampling, we measured rCBF in 39 normal volunteers (19 men and 20 women; mean ages 61 +/- 11 yr for the men and 60 +/- 12 yr for the women). Eighteen neurologically stable patients with prior stroke (mean age = 65 +/- 11 yr) were studied twice at a mean interval of 97 days. In 16 patients (7 men and 9 women, mean age = 63 +/- 5 yr) with subarachnoid hemorrhage, rCBF was measured 1-2 wk after onset. Cerebral vasospasm was evaluated by repeated angiography. The mean rCBF in the vasospastic area was compared with that in a nonvasospastic area. RESULTS: The mean rCBFs of the cerebral cortex and centrum semiovale in the volunteers were 33.0 +/- 5.1 ml/100 g/min and 25.0 +/- 4.5 ml/100 g/min, respectively. There was no age-dependent change in rCBF, but the women showed significantly higher cortical rCBF than the men (p < 0.05). In the stroke patients, the whole-brain CBF values showed high reproducibility, with high correlations between those obtained at the first and second studies (y = -3.5 + 1.03x; r = 0.90; p < 0.001). In the subarachnoid hemorrhage patients, the vasospastic area showed significantly lower rCBF than the normal cortical rCBF (p < 0.01) and the nonvasospastic area (p < 0.01). Brain regions with rCBF levels below 20 ml/100 g/min showed infarction on the follow-up CT scan. CONCLUSION: The IMP-ARG method is reproducible, sensitive to hypoperfusion and feasible for the quantitative evaluation of rCBF in routine clinical practice.

Aged↗
PubMed1997

[Coronary bypass surgery in the elderly: characteristics and quality of life].

From November 1991 to December 1996, 66 patients aged 70 years or more underwent coronary artery bypass grafting (CABG). They were compared with a group of 200 consecutive patients aged less than 70 years of age who underwent CABG during the same period. The elderly patients had a higher incidence of female gender, smaller body structure, left main trunk disease, calcification of ascending aorta and emergency operation. However, there were no significant differences between two groups in hospital mortality, IABP insertion or length of stay in intensive care unit. Quality of life (QOL) of the elderly patients was evaluated for all the 58 survivors by means of Specific Activity Scale Questionnaires. Forty of the 58 patients (69%) had functional capacity of 5 METs or more. All the 43 patients who worked before CABG were able return to work, although some patients reduced their workload. We conclude that CABG in elderly patients can be performed with mortality and morbidity similar to those in younger patients. QOL is generally maintained.

Age Factors↗
PubMed1997

[A case of aortic valve replacement 3 years after coronary artery bypass grafting].

A rare case of aortic valve replacement (AVR) with poor left ventricular function, following coronary artery bypass grafting, was reported. The patient was 57-year-old man who received urgent CABG with 2 saphenous vein grafts 3 years ago. At that time, aortic regurgitation (AR) was grade 2. He suffered acute myocardial infarction 1 year after CABG because of the occlusion the saphenous vein graft to the obtuse marginal branch. Percutaneous transluminal angioplasty was successfully performed for occluded graft. Since then, however, AR increased gradually and the left ventricular function decreased. Three years after the initial operation, he was admitted again with congestive heart failure. Heart catheterization revealed grade 3 AR and 17% left ventricular ejection faction (LVEF). AVR was performed through a median sternotomy and 2 saphenous vein grafts were preserved. He showed uneventful postoperative recovery and is now very well with 40% LVEF.

Angina, Unstable↗
PubMed1997

Bone bonding ability of bioactive bone cements.

The bone bonding ability of three types of bioactive bone cement A, B, and C consisting of glass or glass ceramic powder and bisphenol-alpha-glycidyl methacrylate resin was evaluated. Type A contained MgO-CaO-SiO2-P2O5-CaF2 glass powder; Type B, MgO-CaO-SiO2-P2O5-CaF2 glass ceramic powder; and Type C, MgO free CaO-SiO2-P2O5-CaF2 glass powder. Rectangular plates (2 x 10 x 15 mm) of Types A, B, C, and polymethylmethacrylate cements were implanted into the tibial metaphyses of male rabbits and the failure load measured by mechanical failure testing (detaching test) 10 and 25 weeks after implantation. The failure loads of Types A, B, C, and polymethylmethacrylate cements were respectively, 29.52, 41.48, 28.22, and 0.29 N at 10 weeks and 33.42, 41.27, 33.64, and 0.20 N at 25 weeks. Examination of the bone cement interface revealed that all the bioactive bone cements achieved direct bone contact with the bone. These results showed that all three types of bioactive bone cement have the ability to bond to bone, and the cement containing glass ceramic powder revealed higher bonding strength than did those containing glass powder.

Animals↗
PubMed1997

[Hemodynamic effects of continuous epidural infusion with local anesthetics].

Epidural blockade with local anesthetic may cause hypotension resulting from sympathetic block and/or systemic effect produced by absorbed local anesthetic through epidural blood vessels. In the present study, we compared the hemodynamic effects of saline 0.5 ml.h-1, lidocaine 0.5 ml.h-1, bupivacaine 0.5 ml.h-1, lidocaine 2 ml.h-1, and bupivacaine 2 ml.h-1, which were given epidurally combined with morphine. There was not significant difference in hemodynamics among 5 groups. Continuous epidural infusion with a small dose of local anesthetic agent combined with morphine is unlikely to induce apparent hemodynamic effects during postoperative period.

Adult↗
PubMed1997

[Etiological analysis of thrombophilia].

We have established a system for etiological analysis of thrombophilia which includes assays of antithrombin III, protein C, protein S, plasminogen, fibrinogen, heparin cofactor II and lupus anticoagulants as well as gene analysis. The analysis conducted on 115 patients with venous thrombosis, arterial thrombosis and small vessel thrombosis revealed that forty-one patients(36% of the examined patients) were accompanied with decreased activities of protein S, protein C, antithrombin III and plasminogen. Eleven candidate causal mutations were found by gene analysis. These studies indicate that a comprehensive examination is instrumental in identifying and confirming the etiology in patients with thrombophilia.

Antithrombin III↗
PubMed1997

[A case of impending rupture of coronary aneurysm after rapid growth within a month].

A case of successful surgery for a rapidly growing aneurysm is described. The patient, a 47-year-old woman, had suffered from recurrent aphtous and genital ulcers for 17 years and hyperthyroidism for two years. One month after myocardial infarction, follow-up coronary angiography showed total obstruction at the distal part of the aneurysm in the left anterior descending artery with rapid dilation to 37 mm. Echocardiography revealed gradually increasing pericardial effusion. Urgent surgery was performed on January 11, 1995. Because Behçet's disease was suspected and since the vascular wall was suspected to have become fragile, surgery was performed using the aortic-no-touch technique. Under ventricular fibrillation, the proximal and distal part of the left anterior descending artery of the coronary aneurysm was ligated and bypass grafting was achieved at the distal part of the left anterior descending artery with the left internal thoracic artery. Low dose steroid treatment was started from nine days after surgery. The post operative course was satisfactory and coronary angiography during the first month showed no abnormal signs.

Aneurysm, Ruptured↗
PubMed1997

Fatal pulmonary embolism after total hip arthroplasty. Three Japanese cases.

It has been reported that the incidence of postoperative pulmonary embolism is significantly lower in Asians than in Westerners, however, several recent reports have cited an increase in the incidence in Asia. We have experienced three cases of fatal pulmonary embolism after total hip replacement in Japanese patients. Our three patients had received no preoperative prophylaxis, even though they had risk factors for pulmonary embolism. Prophylaxis for pulmonary embolism seems necessary in Asian patients who are at risk.

Adult↗
PubMed1997

Severe metallosis caused by shaving down of the stem neck due to outer cup impingement of a bipolar endoprosthesis. A case report. off.

The authors report on a patient with severe metallosis caused by shaving down of the stem neck due to outer cup impingement. A primary arthroplasty was performed using an Omnifit bipolar endoprosthesis (Stryker) with an acetabular bone graft fixed by ceramic screws. At the time of revision surgery the synovium was stained black. Two ceramic screws were broken, but no scratch was observed on the metal surfaces of the outer cup and the inner head. The ultra-high molecular weight polyethylene (UHMWPE) of the inner-bearing collar was worn and flat. During the operation, a groove was observed at the stem neck where the outer cup impinges. An analysis of the black pseudocapsule by scanning electron microscopy with electron prove microanalysis (SEMEPMA) revealed that the pseudocapsule contained titanium metal particles. To our knowledge, metallosis caused by the same mechanism has only been reported in four joints, which were replaced by a Zimmer BHP bipolar endoprosthesis and Howmedica bicentric cup.

Female↗
PubMed1997

[A case report of thoracic outlet syndrome with acute arterial obstruction caused by abnormal first rib].

A 33-year-old male was transferred to our hospital because of coldness, numbness and pain in his right arm. Chest X-ray showed abnormal first ribs on both sides that were attached to the second ribs below the clavicles. Angiogram revealed an aneurysm of right subclavian artery, thrombus in the aneurysm and embolism to the brachial artery. Thrombectomy using a Fogarty catheter was done and the radial pulse recovered. Surgical resection of the abnormal first rib and thrombectomy was performed, because ischemic symptoms recurred in spite of anticoagulation and antiplatelet therapy. Acute arterial occlusion in patients with thoracic outlet syndrome is rare. The literature on arterial complications of thoracic outlet syndrome is reviewed.

Acute Disease↗
PubMed1996

Relationship between limb and muscle blood flow in man.

1. Since direct measurement of muscle blood flow in humans has been difficult, estimations of muscle flow have been made from measured total limb blood flow using a classic equation that predicts that the fraction of resting blood flow through muscle tissue decreases as total limb flow increases. 2. We used positron emission tomography and 15O-labelled water to directly quantify resting muscle and total limb blood flow in cross-sections of the femoral region in twenty-eight normal subjects (age, 30 +/- 8 years; body mass index, 24.1 +/- 3.3 Kg m-2) under conditions of constant environmental temperature of 22-23 degrees C. 3. Muscle blood flow averaged 3.1 +/- 1.7 ml (100 ml muscle)-1 min-1 (range, 1.1-7.5 ml (100 ml muscle)-1 min-1 and cross-sectional limb blood flow averaged 2.5 +/- 1.1 ml (100 ml limb)-1 min-1) (range, 1.0-4.8 ml (100 ml limb)-1 min-1). A linear relationship was observed between limb and muscle blood flow, and a regression equation was calculated for estimation of muscle blood flow bases on limb flow: muscle flow = (1.41 +/- 0.10) limb flow - (0.43 +/- 0.28). The slope of this equation was significantly greater than 1 (P < 0.001) indicating that the fraction of blood flow perfusing muscle tissue increases as a function of total limb flow. 4. These data provide a new equation for estimation of resting muscle blood flow in normal subjects, and demonstrate that muscle blood flow is the primary determinant of resting blood flow in man.

Adult↗
PubMed1996

Noninvasive quantification of regional myocardial metabolic rate for oxygen by use of 15O2 inhalation and positron emission tomography. Theory, error analysis, and application in humans.

BACKGROUND: A method has been developed to measure the regional myocardial metabolic rate of oxygen consumption (rMMRO2) and oxygen extraction fraction (rOEF) quantitatively and noninvasively in humans by use of 15O2 inhalation and positron emission tomography. This article describes the theory, an error analysis of the technique, and procedures of the method used in a human feasibility study. METHODS AND RESULTS: Inhaled 15O2 is transported to peripheral tissues, where it is converted to 15O-labeled water of metabolism, which exchanges with the relatively large extravascular tissue space. Quantification of this buildup of radioactivity allows the calculation of rMMRO2 and rOEF. However, a correction for the spillover of the pulmonary gas radioactivity signal into myocardial regions is required and has been made by use of a gas volume distribution estimated from the transmission scan. This was validated by comparative measurements using the inert gas [11C]CH4 in four greyhounds. Spillover of the cardiac chamber radioactivity has been corrected for with an inhaled [13O]CO (blood volume) scan. The underestimation of myocardial radioactivity due to wall motion and thickness has been corrected for by use of values of tissue fraction obtained from the flow measurement [15OKCO2 scan). Values of rOEF were similar (within 4%) whether obtained from gas volume measurements determined from the transmission or [11C]CH4 scan data. 15O2 scan information from six healthy volunteers showed a clear distribution of myocardial radioactivity after the vascular and pulmonary gas 15O background was subtracted. Subsequent compartmental analysis resulted in values for rOEF and rMMRO2 of 0.60 +/- 0.11 and 0.10 +/- 0.03 mL.min-1.g-1 in the human myocardium at rest. CONCLUSIONS: The results of this study are in good agreement with established values. This is the first known approach to allow the direct quantitative determination of rOEF and oxygen metabolism to be made noninvasively on a regional basis.

Adult↗