PubMed Health⌕ Search

Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 145 records · Page 8Linked to original sources
PubMed1999

Osteonecrosis of the femoral head associated with pregnancy.

A 31-year-old pregnant woman suddenly complained of bilateral hip pain 2 weeks before delivery. She was delivered of triplets by Caesarean section. She had been treated with human menopausal gonadotropin and human chorionic gonadotropin (hMG-hCG) before pregnancy. Radiograms of the hip joint showed collapse of the femoral heads bilaterally. Magnetic resonance imaging revealed a band pattern of low signal intensity for both hips on T1- and T2-weighted images. She had no history of steroid therapy or alcohol abuse. Osteonecrosis of the femoral heads bilaterally associated with pregnancy was confirmed. Pathology of the femoral head showed typical empty lacunae and necrosis of the trabecula.

Adult↗
PubMed1999

Effects of recombinant human erythropoietin on thrombosis and fibrinolysis in autologous transfusion for hip surgery.

Recombinant human erythropoietin (rHuEPO) is effective in allowing autologous blood donation in patients unable to donate because of anemia. As adverse effects of rHuEPO might include activation of coagulation and possibly fibrinolysis, we investigated these possibilities in the context of autologous blood donation preceding hip surgery. Thirty-seven patients who donated 800 ml of autologous blood for elective hip surgery were randomly assigned to either a group of 20 receiving preoperative treatment with rHuEPO (erythropoietin beta), 6000 U i.v. twice weekly for 3 weeks, or an untreated control group of 17. A significant increase in platelet count was associated with autologous blood donation and intraoperative blood loss with or without rHuEPO. Coagulation and fibrinolysis were increased significantly by intraoperative blood loss in both groups, but not by rHuEPO. Coagulation and fibrinolysis were not activated by rHuEPO for elective hip surgery.

Adult↗
PubMed1999

Predictive factors for mortality and cerebral complications in arteriosclerotic aneurysm of the aortic arch.

BACKGROUND: The incidence of cerebral complications is high in patients with aortic arch aneurysm. METHODS: Between December 1977 and December 1995, 246 patients with arteriosclerotic arch aneurysm underwent operation. Thirty-nine patients had an aneurysm involving the entire arch, 193 had only distal arch aneurysm, and 14 had arch aneurysm extending to the descending aorta. Eighty-seven patients underwent replacement of the total arch, 85 had replacement of only the distal arch, 14 had simultaneous replacement of the descending aorta, 45 had patch repair, and 15 had thromboexclusion. Selective cerebral perfusion was used in 112 patients and partial bypass in 58 in the earlier series of patients, but deep hypothermic circulatory arrest with retrograde cerebral perfusion technique was exclusively applied in the most recent 76 patients. RESULTS: There were 50 (20%) early deaths and 37 (19%) late deaths. Postoperative stroke was found in 26 (11%) patients of which 13 (50%) died. Mutual predictive factors for postoperative mortality and stroke were earlier series, preoperative chronic renal failure, ruptured aneurysm, arch clamping during procedure, and using partial cardiopulmonary bypass. Among 129 patients operated on during the most recent 5 years, early mortality and incidence of stroke decreased to 14.7% and 6.9%, respectively. CONCLUSIONS: Results of operations for arteriosclerotic aneurysms of the transverse aortic arch in 246 patients during a period of 17 years have been improving but are still not satisfactory.

Adult↗
PubMed1999

Surgical treatment of Behçet's disease involving aortic regurgitation.

BACKGROUND: Behçet's disease involving aortic regurgitation is rare, and prosthetic valve detachment after aortic valve replacement is one of the most serious complications reported. We investigated the surgical results in 10 patients with aortic regurgitation caused by Behçet's disease. METHODS: Between 1981 and 1997, 10 patients with aortic regurgitation secondary to Behçet's disease had surgery. There were 8 men and 2 women, and their ages ranged from 33 to 60 years (mean, 46+/-8 years). The surgical procedures for aortic regurgitation were aortic valve replacement in 6 patients and Bentall type operation in 4. RESULTS: No patient died during the hospital stay. The follow-up periods ranged from 11 to 185 months (mean, 87 months). Two patients died during the follow-up period. The acturial survival rate was 89% at 5 years and 67% at 10 years. Prosthetic valve detachment or suture detachment requiring redo operation occurred in 4 patients, 3 of whom had redo operations twice. Four patients had a composite graft replacement, and 1 patient died after the operation. No prosthetic valve detachment was noted in 64% of the patients at 5 years and in 43% at 10 years. CONCLUSIONS: The rate of prosthetic valve detachment was 40% (4 of 10 patients), with a higher incidence in patients with Behçet's disease than in those treated during the same period at the same hospital for aortitis caused by other diseases. Surgical techniques for treatment of this condition should be modified to improve the surgical outcome in these patients.

Adult↗
PubMed1999

Is distal anastomosis only to the true channel in chronic type B aortic dissection justified?

BACKGROUND: We investigated long-term outcomes of the distal false lumen of the aorta and aortic branches after distal anastomosis of the graft only to the true lumen in chronic type B aortic dissection. METHODS: From November 1979 until June 1998, we treated 98 patients without Marfan syndrome who had chronic type B aortic dissection and underwent replacement of the descending aorta, 79 of whom had distal anastomosis to the true lumen only. The celiac artery originated from the false lumen in 11 patients, superior mesenteric artery in 5, right renal artery in 19, and left renal artery in 16. RESULTS: There were 12 (15.1%) early deaths. Spinal cord ischemia was detected in 5 patients. Postoperative follow-up was achieved in 67 patients, and 13 patients died. Postoperative survival at 10 years was 67.6% +/- 7.1%. Eight patients had complete occlusion of the distal false lumen, 54 patients had occlusion of the false lumen down to the celiac artery, and 5 patients had a patent false lumen. Four patients required further replacement of the thoracoabdominal aorta. CONCLUSIONS: In non-Marfan patients with chronic type B aortic dissection, the false lumen distal to the graft anastomosis was likely to be thrombosed when the graft was anastomosed to the true lumen only. Postoperative visceral circulation was not compromised, but spinal cord ischemia is a problem that remains to be solved.

Adult↗
PubMed1999

Autofluorescence in human dentine in relation to age, tooth type and temperature measured by nanosecond time-resolved fluorescence microscopy.

Stationary and dynamic characteristics of autofluorescence in human dentine were examined with a nanosecond time-resolved fluorescence microphotometer. With ageing, the intensity of the fluorescence increased whereas the decay time decreased. There were no differences in fluorescence intensity, decay time or spectral profile among tooth types taken from the same individuals or from individuals of the same age. Fluorescence intensity was enhanced after the application of heat (37 and 50 degrees C), but remained unchanged when specimens were kept at 4 degrees C. These results suggest that the increase in fluorescence intensity was partially due to a temperature-dependent physicochemical mechanism.

Aged↗
PubMed1999

Strain differences of the ability to hydroxylate methotrexate in rats.

Converting activity of methotrexate (MTX) to 7-hydroxymethotrexate (7-OH-MTX) was examined using eight strains of rats. Marked variability of the activity was found in liver cytosols from the rats. The highest activity was observed with Sea:SD rats, followed by LEW/Sea and Jcl:Wistar rats. The lowest activity was observed with WKA/Sea rats. The difference in the activity between Sea:SD and WKA/Sea strains was 104-fold. The variation was correlated to the strain difference of benzaldehyde oxidase activity in the rats. The cytosolic 7-hydroxylase activities in other tissues of Sea:SD rats were much higher than those of WKA/Sea, similarly to the case in liver. The liver microsomes of Sea:SD rats exhibited no 7-hydroxylase activity toward MTX even in the presence of NADPH. The cytosolic 7-hydroxylating activity of the livers of Sea:SD rats was inhibited by menadione, beta-estradiol, chlorpromazine and disulfiram, inhibitors of aldehyde oxidase, but not oxypurinol, an inhibitor of xanthine oxidase. The purified aldehyde oxidase from the livers of Sea:SD rats exhibited a significant 7-hydroxylating activity toward MTX. However, xanthine oxidase had no ability to hydroxylate MTX. These facts suggest that MTX hydroxylating activity in rats is predominantly due to aldehyde oxidase, and the strain differences are due to the variations of the flavoenzyme level.

Aldehyde Oxidase↗
PubMed1999

Catastrophic failure of cementless total hip arthroplasty using a femoral component without surface coating.

Consecutive series of 90 hips that had had a primary cementless arthroplasty with use of straight collarless stems between January 1988 and September 1992 were reviewed. Twenty-eight hips with Omnifit Normalized Stems (Fit-N) and 45 hips with Omniflex Normalized Stems (Flex-N) without porous coatings were compared clinically and radiographically with 17 hips with Omnifit Microstructured Stems (Fit-M) with porous coating. The average follow-up periods for the 3 stems were 97 months, 73 months, and 93 months. Revision was performed or awaited in 9 cases (32.1%) in the Fit-N group, 18 cases (40.0%) in the Flex-N group, and 1 case (5.8%) in the Fit-M group. The average annual subsidence was 0.62 mm/y, 0.73 mm/y, and 0.17 mm/y. Osteolysis of more than 3 mm occurred in 28.6%, 37.8%, and 23.5%. Fit-N stems and Flex-N stems without porous coatings are not appropriate for cementless total hip arthroplasty.

Bone Cements↗
PubMed1999

Elevated plasma brain natriuretic peptide levels in chronic respiratory failure with cor pulmonale.

Elevated plasma brain natriuretic peptide (BNP) levels have been described in patients with congestive heart failure and acute myocardial infarction. We measured plasma BNP levels in patients with chronic respiratory failure to evaluate the correlation between plasma BNP levels and pulmonary haemodynamics. Plasma BNP levels were measured in 28 patients with chronic respiratory failure accompanied by three underlying diseases [14 with chronic obstructive pulmonary disease (COPD), seven with sequelae of pulmonary tuberculosis (sequelae Tbc) and seven with diffuse panbronchiolitis (DPB)] by immunoradiometric assay methods (IRMA). Twenty-one of 28 patients had already received oxygen supplementation and 16 of 21 patients were treated as outpatients with home oxygen therapy. Plasma BNP levels were significantly elevated in patients with chronic respiratory failure complicated by cor pulmonale (81.5 +/- 13.1 pg ml-1) compared to patients without cor pulmonale (13.3 +/- 2.7 pg ml-1, P < 0.001). As controls, plasma BNP levels in 10 patients with primary lung cancer were studied, and the results (3.5 +/- 1.0 pg ml-1) were not significantly different from those of patients with chronic respiratory failure without cor pulmonale. Plasma BNP levels in 12 healthy subjects were also studied, and the results (7.2 +/- 1.0 pg ml-1) were not significantly different from those of the control subjects. Plasma BNP levels showed a weak linear correlation with systolic pulmonary arterial blood pressure, estimated by Doppler echocardiography (r = 0.43; P = 0.068), but there was no significant correlation between BNP levels and the degree of hypoxaemia (r = 0.30; P = 0.138). Plasma atrial natriuretic peptide (ANP) levels in patients with chronic respiratory failure were also measured using the same samples. Plasma ANP levels were also significantly elevated in patients with chronic respiratory failure complicated by cor pulmonale (80.8 +/- 12.1 pg ml-1) compared to patients without cor pulmonale (26.1 +/- 4.4 pg ml-1, P = 0.003). A significant correlation was found between plasma BNP and ANP levels (r = 0.68; P < 0.001). Our results suggest that the plasma BNP or ANP level may be a useful indicator for detecting the presence of cor pulmonale in patients with chronic respiratory failure.

Adult↗
PubMed1999

Use of expanded polytetrafluoroethylene sutures as artificial tendinous cords in children with congenital mitral regurgitation.

OBJECTIVE: To determine the efficacy in the intermediate term of artificial cords inserted in children with congenital mitral regurgitation. METHODS: We reconstructed the tendinous cords using expanded polytetrafluoroethylene (ePTFE) sutures in 11 children with severe mitral regurgitation. In these patients, the aortic (anterior) leaflet of the mitral valve had been markedly prolapsed, the tendinous cords being partially lacking in seven, and elongated in the remaining four. In addition, one of the papillary muscles was hypoplastic in five and absent in three. The number of artificial cords constructed varied from two to six. Conventional annuloplasty was performed in all to plicate the dilated annular attachment of the valve. Ventricular septal defect was present in four patients, and other associated malformations in another two. Age at operation ranged from 9 months to 9 years old, with a mean of 4.5 years. RESULTS: All patients survived the operation. No reoperation has been needed thus far. No complications were encountered related to the use of the prosthetic materials or anticoagulation. As judged by echocardiography, regurgitation became trivial or slight immediately after the repair. In two patients, however, regurgitation recurred within 1 year of the operation. Coaptation between the leaflets was maintained by a compensatory growth at the site of attachment of the artificial cords. Catheterization demonstrated significant improvements in the end-diastolic volume of the left ventricle. CONCLUSION: Expanded polytetrafluoroethylene sutures can be used as artificial cords when attempting to repair the malformed mitral valve in children, providing excellent results in the short- and the intermediate-term after the surgical procedure.

Child↗
PubMed1999

Ventricular outflow tracts after Kawashima intraventricular rerouting for double outlet right ventricle with subpulmonary ventricular septal defect.

OBJECTIVE: To determine whether or not the ventricular outflow tracts can be efficiently constructed in patients with double outlet right ventricle with subpulmonary ventricular septal defect by the Kawashima intraventricular rerouting in which the morphologically right ventricular outlet is divided into two, one for the systemic and the other for the pulmonary circulations. METHODS: The intraventricular rerouting procedure was carried out in nine patients with this particular malformation. Age at repair ranged from 35 days to 3 years old. The distance between the attachments of the tricuspid and the pulmonary valves was 10 mm or greater in all except one patient in whom the measured value was 3 mm. Resecting subaortic musculature appropriately, a tailored patch, either oval-shaped (in seven) or heart-shaped (in two), was placed to construct an unobstructed channel for the left ventricular outflow tract with its diameter greater than that of the anticipated normal aortic orifice at the time of repair. For an unobstructed channel to the pulmonary arteries, enlargement of the right ventricular outflow tract was carried out using a patch in six. RESULTS: All patients survived the operative procedure. On postoperative catheterization, mean pulmonary arterial pressure was 15 +/- 8 mmHg, and cardiac index was calculated as 3.3 +/- 0.6 l/min per m2. It proved that the constructed left ventricular outflow tract can become larger in the longer term. Pressure gradient across the left ventricular outflow tract was greater than 20 mmHg in two patients in the intermediate term. One of these two underwent reoperation for the obstruction 10 years after the initial repair. It was suspected that use of a heart-shaped internal conduit, which seems to result from inadequate conal resection, was one of the possible causes of such obstruction in the longer term. Pressure gradient of 47 mmHg was seen across the right ventricular outflow tract in one patient, although this patient has undergone no reoperation. Enlargement of the right ventricular outflow tract could minimize postoperative obstruction for the pulmonary pathway. CONCLUSIONS: The intraventricular rerouting remains one of the attractive surgical options for repair in this particular setting, in terms of successful construction of the ventricular outflow tracts.

Child, Preschool↗
PubMed1999

The formation of two layers detectable by intraoperative echocardiography is a reliable predictor of late thrombosis within the false lumen of a dissected aorta.

The subjects consisted of one patient with chronic type A and three patients with chronic type B aortic dissection, who underwent replacement of an aorta obliterating distal false lumen. After the repair, the formation of two layers was detected by direct scanning echocardiography within the false lumen even during heparinization. In all cases, postoperative computed tomography confirmed complete thrombosis of the false lumen. The formation of two layers was considered to be a reliable predictor of late thrombosis.

Adult↗
PubMed1999

Early and long-term results of surgery for aneurysms of the thoracic aorta in septuagenarians and octogenarians.

OBJECTIVE: The purpose of this study was to demonstrate early and long-term results of surgery for thoracic aortic aneurysm in patients over 70 years of age compared with those of patients under 70 years and to clarify the clinical problems peculiar to this subset of patients. PATIENTS AND METHODS: Of 1157 patients who underwent surgery for thoracic aortic aneurysm from 1978 to December 1997, 261 who were 70 years or older were selected for analysis. Mean age at the time of surgery was 74.4 +/- 3.5 years. Aneurysms were atherosclerotic in 177 patients and aortic dissection in 84. Acute aortic dissection was found in 25 patients and ruptured aneurysm in 44. The control group consisted of 896 patients under 70 years. Preoperative complications such as AAA, peripheral arterial disease, emphysema, and old cerebral infraction were more common in the older group. Operative procedures consisted of replacement of the ascending aorta or hemiarch in 51 patients, total arch replacement in 75, distal arch replacement in 35, descending aorta replacement in 75, replacement of the thoracoabdominal aorta in 28, and extra-anatomical repair and others in 15. The technique of extracorporeal circulation was selective cerebral perfusion in 69 patients, deep hypothermic circulatory arrest in 90, femoro-femoral bypass in 39, left heart bypass in 12, and temporary aorto-arterial bypass in 30, and others in 21. RESULT: Early mortality was 21% (54 patients), which was greater than that of the control group (113 patients, 13%, P < 0.01). The incidence of postoperative stroke, transient brain dysfunction, and respiratory problems was higher in the study group (P < 0.01 in all). Mean duration in ICU among survivors was 9.3 +/- 20.2 days and that of the control group was 5.9 +/- 2.8 days (P < 0.01). In a recent series (from 1991 to 1997) postoperative mortality improved to 15.6% (30/192 patients) in the study group however this result was still inferior to that of the control group (8.6%, 39/452, P = 0.03) however mortality of emergency surgery during the same periods was still high (31%, 11/35 patients). Logistic regression analysis revealed that significant risk factors for postoperative hospital death were surgery before 1991, age over 70 years, preoperative cardiac problems, aneurysm rupture, postoperative stroke, low output syndrome, bleeding, and acute renal failure. Postoperative follow-up was obtained in 408 patients/year and the longest period was 10.2 years. Late deaths were documented in 31 patients. Five-year and 10-year survival were 61.2 +/- 5.7% and 31.3 +/- 16.4%, respectively. In the control group the 5-year and 10-year survival were 78.0 +/- 2.1% and 62.5 +/- 4.0%, respectively (P = 0.03). However, survival of the early survivors in the study group was similar with that of the age-matched normal population. Aortic reoperation was performed in 13 patients. Freedom from aortic reoperation was 86.7 +/- 4.2% at 5 years and 80.5 +/- 7.1% at 10 years in the study group and 83.4 +/- 1.8% at 5 years and 64.1 +/- 13.3% at 10 years in the control group (P = 0.27). CONCLUSION: Although recent advances have been achieved, early and long-term results of surgery for thoracic aortic aneurysm in patients older than 70 years were less satisfactory compared with those of patients under 70 years of age, especially in patients who required emergency surgery. Preoperative disorder of the vital organ systems was considered to be the main causative factor for high mortality, however, pertinent surgical strategies are necessary to improve the outcome of elderly patients.

Age Factors↗
PubMed1999

Comparative Surface Studies at Atomic Resolution with Ultrahigh Vacuum Variable-Temperature Atomic Force and Scanning Tunneling Microscopes.

: With the ultrahigh vacuum variable-temperature scanning tunneling microscope (UHV-VT-STM), atomic-level observation has been achieved. An ultrahigh vacuum atomic force microscope (UHV-AFM) has also been developed, with success in obtaining atom images where observation in noncontact (NC) mode with a frequency modulation (FM) detection method was attempted. Using the FM detection method in the constant oscillation amplitude of the cantilever excitation mode, we have obtained atomic-resolution images of Si(111) 7 x 7 structures and Si(100) 2 x 1 structures and other structures together with STM images in an ultrahigh vacuum environment. Also shown here are contact potential difference (CPD) images using the NC-AFM method.

Journal Article↗
PubMed1999

Interaction between surface active drug (FK906:rennin inhibitor) and cyclodextrins in aqueous solution.

The aggregation behavior of FK906, which is a peptide like hypertensive agent, in aqueous solution was studied by static light scattering, 1H-nuclear magnetic resonance (NMR), and surface tension. These experiments showed a clear critical micelle concentration (cmc) at around 6.3 x 10(-3) to 1.3 x 10(-2) M of FK906 aqueous solution. The result of 1H NMR experiments revealed that FK906 aggregates primarily by hydrophobic interactions involving the benzyl moiety. The Debye plots from light-scattering studies showed that the apparent molecular weight of aggregated FK906 molecule is 1670 which corresponds to 2-3 molecules of FK906. The effect of alpha- and beta-cyclodextrins on the surface tension of FK906 aqueous solution was investigated. It appeared that the addition of alpha-cyclodextrin showed very small shift of cmc, but that of beta-cyclodextrin shifted the cmc to much higher concentration. The investigation on the surface tension of FK906 aqueous solution in the presence of beta-cyclodextrin indicated that FK906 forms a 1:1 complex with beta-cyclodextrin. On the basis of these experiments, it appears that beta-cyclodextrin has an ability to change the surface active property of FK906 in its aqueous solution. Therefore, it is expected that the addition of beta-cyclodextrin to FK906 aqueous solution may prevent the adsorption onto container walls and/or reduce the local irritancy.

Antihypertensive Agents↗
PubMed1999

Cytokine-induced neutrophil chemoattractant in a rat model of lipopolysaccharide-induced acute lung injury.

To elucidate the role of major chemotactic factors, cytokine-induced neutrophil chemoattractant (CINC), leukotriene B4 (LTB4) and C5a in lipopolysaccharide (LPS)-induced acute lung injury in rat, we employed three reagents: anti-CINC-1 antibody, an LTB4 receptor antagonist (ONO-4057) and an anti-complementary agent (K-76COONa). Rats were divided into five groups: (1)control group; (2) LPS group, which received intratracheal instillation of LPS (100 microg/kg); (3) Anti-CINC group, which received intratracheal coinstillation of LPS with anti-CINC-1 antibody (1 mg/kg); (4) LTB4-Ra group, which received intravenous ONO-4057 (10 mg/kg) prior to intratracheal LPS; (5) Anti-C5a group, which received intravenous K-76COONa (100 mg/kg) prior to intratracheal LPS. The number of neutrophils in bronchoalveolar lavage (BAL) fluids 6 h after LPS instillation was significantly reduced in the Anti-CINC group, however, no reduction was found in either the LTB4-Ra group or Anti-C5a group. The levels of CINC-1, CINC-2alpha and CINC-3 in BAL fluids were significantly higher in the LPS group than in the saline-instilled control group. In vitro, the production of CINC-1 and CINC-3 from LPS-stimulated macrophages was significantly elevated compared to unstimulated macrophages 6 h later. The increase in CINC-2alpha production was markedly less than that of CINC-1 or CINC-3. These results indicate that CINCs, especially CINC-1 and CINC-3 play an important role in the recruitment of neutrophils to the lung in LPS-induced acute lung injury.

Albumins↗