Biomedical subjects

N Sugano

Publications and source records attributed to N Sugano.

At least 55 records · Page 3Linked to original sources

PubMed2000

Matrix metalloproteinases in patients with osteoarthritis of the hip.

In 78 patients undergoing a total hip replacement we examined the production of matrix metalloproteinases (MMP) by the fibroblasts from the connective tissue of the acetabulum; we then correlated these findings with clinical and radiological characteristics of the same patients. In 53 patients only MMP-2 was produced; in 15 cases MMP-1, -2 and -3 were present; and in 10 cases not only MMP-1, -2, -3 but also MMP-9. Significant differences among the clinical and radiological parameters were found in the 3 subsets. A positive correlation between the production of MMP-9 and a rapid destruction of the hip joint was found.

Adolescent↗

PubMed2000

Pathology of femoral head collapse following transtrochanteric rotational osteotomy for osteonecrosis.

We investigated the pathology of femoral head collapse following transtrochanteric anterior rotational osteotomy. Six femoral heads were obtained during total hip arthroplasty some 2-12 years after osteotomy. In all cases, the preoperatively necrotic lesions exhibited mostly osteonecrosis with accumulation of bone marrow cell debris and trabecular bone with empty lacunae, although repair tissue such as granulation tissue and appositional bone formation were observed in limited areas in some cases. In the transposed intact articular surface of the femoral head, osteoarthritic changes such as fissure penetration to the subchondral bone and osteophyte formation were commonly observed. In newly created subchondral areas at weight-bearing sites, trabecular thickness and the number of trabecular bones had decreased, with few osteoblasts, osteoclasts, and osteocytes being present, resulting in a coarse lamellar structure of the trabecular bone. These findings suggest that transposed areas in cases of failure consist mostly of low-turnover osteoporotic lesions which could cause collapse of the femoral head.

Adult↗

PubMed2000

Optimizing femoral anteversion and offset after total hip arthroplasty, using a modular femoral neck system: an experimental study.

To investigate the effectiveness of a modular femoral neck system, consisting of two neutral and four types of retroverted necks for the correction of femoral anteversion and offset in total hip arthroplasty, an experimental study was carried out, using sawbones with four different angles of femoral anteversion (16 degrees, 34 degrees, 47 degrees, and 59 degrees ). With the neutral neck, reconstruction of the preoperative anteversion and offset in the normal femur was achieved. While the 15 degrees retroverted long neck was effective for the mildly or moderately anteverted femur, this retroverted neck showed insufficient correction for the severely anteverted femur. This modular neck system proved to be useful for correction of the medial component of femoral offset in femora with anteversion of less than 47 degrees. For patients with greater anteversion, a feature which is rarely seen in the clinical situation, femoral necks with a greater degree of retroversion may be useful.

Arthroplasty, Replacement, Hip↗

PubMed2000

Serial magnetic resonance imaging in a non-traumatic rabbit osteonecrosis model: an experimental longitudinal study.

We investigated the time-dependent natural course of experimental osteonecrosis (ON), including initial changes in ON and the reparative process, using in vivo serial repetitive magnetic resonance imaging (MRI) in a non-traumatic rabbit serum sickness ON model. Some necrotic lesions were detected at 1 week (3 of 16 femora with necrotic lesions) and some in the metaphysis were detected by 12 weeks (2 of 6 femora with lesions) on T(1)-weighted, T(2)-weighted, and fat suppression T(1)-weighted images. On contrast-enhanced MRI, extravasation of the erythrocytes was detected at 72 h (7 of 26 femora with lesions) as a small, focal enhanced area. Necrotic lesions were detected in all abnormal femora by 6 weeks (16 of 16 femora with lesions) as focal, homogeneously or inhomogeneously enhanced areas. Reparative tissue replaced with new vascular and trabecular formation in necrotic areas was detected as an extended marginal enhanced area at 12 weeks. These results suggest that the enhancement patterns on contrast-enhanced MRI may provide helpful information about the developmental and reparative process of clinical ON.

Animals↗

PubMed2000

Osteonecrosis of the patella in patients with nontraumatic osteonecrosis of the femoral head: MRI findings in 60 patients.

We examined both knees in 60 patients with nontraumatic osteonecrosis of the femoral head with three-dimensional MRI. We found osteonecrosis of the patella in 9 patients (10 knees) and osteonecrosis of the femoral or tibial condyles/metaphyses in 35 patients (61 knees). In the patella, the necrosis was located in the proximal half and tended to develop in patients with other necrotic lesions in the knee.

Adolescent↗

PubMed2000

Scintigraphic assessment of the rotated femoral head after transtrochanteric rotational osteotomy for osteonecrosis.

BACKGROUND: The purpose of this study was to assess the usefulness of bone scintigraphy in predicting progressive collapse of the femoral head after transtrochanteric rotational osteotomy for the treatment of osteonecrosis of the femoral head. METHODS: We studied thirty-three hips in thirty patients with osteonecrosis of the femoral head who had undergone transtrochanteric rotational osteotomy. There were twenty male and ten female patients, with a mean age of 34.4 years at the time of the operation. The mean duration of follow-up was 10.0 years. According to the staging system of Ficat and Arlet, there were nineteen stage-2 hips and fourteen stage-3 hips at the time of the operation. Conventional anteroposterior and lateral radiographs were assessed. In addition, bone scans were performed at three weeks after the operation to predict the outcome with regard to the rotated femoral head. On the basis of the location of low scan activity within the femoral head, the scintigraphic findings were classified into one of two categories: type A if there was no low scan activity in the weight-bearing area of the femoral head or type B if low scan activity occupied the entire weight-bearing area. Six hips with collapse were studied histologically. RESULTS: Postoperative scintiscans revealed sixteen type-A hips and seventeen type-B hips. Of the type-A hips, only three exhibited progressive collapse of the femoral head after the osteotomy, whereas fourteen of the type-B hips exhibited progressive collapse. A significant association was found between the postoperative scintigraphic findings and the final radiographic result (p < 0.01). CONCLUSIONS: Bone scintiscans made three weeks after transtrochanteric rotational osteotomy were useful for predicting the final clinical result.

Adult↗

PubMed2000

Evaluation of periprosthetic bone-remodeling after cementless total hip arthroplasty. The influence of the extent of porous coating.

BACKGROUND: Total hip arthroplasty changes the levels of stress within the proximal part of the femur, and the femur remodels adjacent to the prosthesis. The stem size and the initial bone-mineral density around the distal portion of the stem affect postoperative bone-remodeling after the insertion of a fully porous-coated metal-cancellous prosthesis. The purpose of this study was to evaluate the influence of the extent of porous coating of this prosthesis on femoral bone-remodeling. METHODS: A longitudinal examination of sixty-one hips in fifty-four patients was performed. Thirty-one hips in twenty-seven patients with a fully porous-coated stem (Group A) and thirty hips in twenty-seven patients with a proximally porous-coated stem (Group B) were followed for twenty-four to thirty months. Periprosthetic bone-mineral density was measured with dual-energy x-ray absorptiometry at specific intervals after the operation. RESULTS: In both groups, the greatest loss of bone-mineral density, compared with the initial (three-week) value, was approximately 20 percent in zone 7 at twelve to eighteen months. In other zones, bone-remodeling appeared to cease by twelve months. At the last follow-up evaluation, the loss of bone-mineral density in the distal and middle regions in Group A was significantly greater than that in Group B (p < 0.01 for zone 3 and p < 0.05 for zone 6). In contrast, with the numbers available, there were no significant differences in loss of bone-mineral density in the proximal regions (zones 1 and 7) between the two groups at any follow-up period. CONCLUSIONS: The extent of porous coating affects bone-remodeling in the distal periprosthetic region rather than in the proximal region. The results in the present report are specific to the particular implants that were studied.

Absorptiometry, Photon↗

PubMed2000

Detection of mitochondrial DNA mutations in human gingival tissues.

The accumulation of mitochondrial DNA mutation is an important contributor to the aging process. Polymerase chain reaction (PCR) amplification was carried out on total DNA from gingival tissues of human subjects with ages of 19 to 64 years, and 5.0-kb and 7.4-kb deletions were found in the mitochondrial genomes of these subjects. This is the first report of mitochondrial DNA deletion detectable in human gingival tissues.

Adolescent↗

PubMed1999

Enhancement of excision repair of cisplatin-DNA adducts by cell-free extract from a cisplatin-resistant rat cell line.

To characterize the enhanced repair synthesis of defined DNA lesions, oligodeoxyribonucleotides were synthesized and inserted into plasmid DNA. The inserted plasmid DNA was treated with cis-diamminedichloroplatinum(II) (cisplatin) and subjected to in vitro DNA repair assay with soluble extract from the rat liver cell line Ac2F. All cisplatin adducts tested stimulated DNA repair synthesis. Moreover, two cisplatin-resistant cell lines, Ac2F-CR4 and Ac2F-CR10, were established by stepwise exposure of Ac2F cells to this drug. The DNA repair synthesis was enhanced 3- to 4-fold in the extract from cisplatin-resistant Ac2F cells relative to that from Ac2F cells. Such repair synthesis was suppressed by the specific DNA polymerase inhibitor aphidicolin. The results of the present study suggested that the enhanced repair activity induced by a cisplatin adduct can be detected by in vitro DNA repair assay with soluble cell extract.

Animals↗

PubMed1999

Cyclosporin A inhibits H2O2-induced apoptosis of human fibroblasts.

Several clinical studies have shown that cyclosporin A (CsA) is effective for treating a variety of chronic inflammatory and autoimmune diseases. Because reactive oxygen species are believed to play a key role in the development of these diseases, causing cell apoptosis, we investigated whether CsA inhibits H2O2-induced apoptosis. Preincubation of human fibroblasts with CsA dose-dependently decreased H2O2-induced apoptosis. Apoptosis suppression by CsA was correlated with the prevention of mitochondrial dysfunction and caspase activation. Thus, our results suggest that the inhibition of apoptosis by CsA may at least partly contribute to the anti-inflammatory effect of CsA.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

Contrast-enhanced magnetic resonance imaging in a nontraumatic rabbit osteonecrosis model.

We investigated early osteonecrosis using in vivo magnetic resonance imaging in a nontraumatic rabbit model of serum-sickness osteonecrosis in which osteonecrosis was induced after two intravenous injections of horse serum with a 3-week interval. One week (group A, 17 rabbits) and 3 weeks (group B, 13 rabbits) after the second serum injection, coronal magnetic resonance images of the femur were obtained and it was removed for histological study. Some of the necrotic lesions in the diaphysis were detected on T1-weighted, T2-weighted, or fat-suppression T1-weighted images (six of 24 necrotic lesions in group A and 16 of 18 in group B), and all of the necrotic lesions in the epiphysis, metaphysis, and diaphysis were detected on T1-weighted or fat-suppression T1-weighted images enhanced with gadolinium-diethylene triamine pentaacetic acid. All focal homogeneous enhanced areas on T1-weighted or fat suppression T1-weighted images corresponded to necrotic lesions (22 of 24 necrotic lesions in group A and 18 of 18 in group B); the contours of the enhanced areas were displayed more clearly on the fat-suppression T1-weighted than on the T1-weighted images. The fat-suppression T1-weighted image enhanced with gadolinium-diethylene triamine pentaacetic acid was thus the most sensitive and specific of five kinds of magnetic resonance images for the detection of early necrotic lesions. The results suggest that this image may be useful for early diagnosis of clinical osteonecrosis and for obtaining information about the pathomechanism of osteonecrosis.

Animals↗

PubMed1999

Stem length and canal filling in uncemented custom-made total hip arthroplasty.

We reviewed 60 custom-made femoral components of two different lengths : 125 mm (group A) and 100 mm (group B), in order to investigate the relationship between stem length and canal filling in uncemented custom-made total hip arthroplasty. There were no statistical differences between the two groups in age, gender, height, body weight, canal flare index, or bowing angle of the femur. Postoperatively there was no statistical difference between the two groups in the proximal canal filling, but significant difference in the distal canal filling (75.5% vs 85.8% on the anteroposterior view and 76.0% vs 82.5% in the lateral view, P<0.001). The distal canal filling inversely correlated with the ratio of the proximal portion and the distal portion of the stem curvature on the lateral view (lateral curve ratio of the stem, P=0.002). We conclude that superior filling at both the proximal and the distal levels can be obtained by using 100-mm custom made components with a small lateral curve ratio.

Adult↗

PubMed1999

Predicting the position of the femoral head center.

To find an accurate method to predict the position of the normal head center in severely deformed hips without a contralateral reference, we studied the relationships between the head center and dimensions of the normal proximal femur using cadaveric specimens. From a large anatomic collection, 32 cadaveric femora with neck-shaft angles ranging from 115 to 146 were selected. The two parameters with the greatest correlation with the height of the femoral head were the height of the neck isthmus (r = .932) and the lowest point of neck saddle (r = .790). Medial head offset was most strongly correlated with the offset of the neck isthmus (r = .945) and the distance from the medullary axis to the outer borders of the medial cortex at the +30% level (r = .861). As a rule of thumb, the height of the head center can be predicted as the height of the midpoint of the neck isthmus plus 10 mm or as the height of the neck saddle with an accuracy of +/-5.1 mm and +/-8.3 mm. The offset of the head center can be predicted as the offset of the midpoint of the neck isthmus plus 15 mm or as the distance from the medullary axis to the medial cortex at the +30% level plus 15 mm with an accuracy of +/-4.6 mm and +/-6.3 mm.

Adult↗

PubMed1999

Planning acetabular redirection osteotomies based on joint contact pressures.

Acetabular redirection osteotomy can be used to relieve pain, improve function, and extend the life of dysplastic hip joints. To understand better the factors that may determine the acetabular reorientation that minimizes pressures, joint contact pressures were calculated by computer assisted methods in 70 dysplastic and 12 normal hips (82 patients). Calculated pressures were consistent with pressures estimated and measured by other investigators. Contact areas were 26% smaller, and contact pressures were 23% higher, in the dysplastic hips compared with the normal hips. When the acetabula were reoriented to minimize contact pressures for an activity such as the midstance phase of gait, then contact pressures were elevated for dissimilar activities such as stair ascent. Contact pressures in the dysplastic hips were reduced when the acetabula were rotated in the frontal plane to increase lateral coverage or rotated in the sagittal plane to increase anterior coverage. In most of the dysplastic hips, contact pressures were reduced twice as much when the acetabulum was rotated in the frontal and the sagitta' planes. Computer assisted methods to quantify joint contact pressures can be used to assess potential candidates for reconstruction, plan acetabular redirection surgery, and possibly may improve the long term success of acetabular redirection osteotomy.

Acetabulum↗

PubMed1999

Diagnostic criteria for non-traumatic osteonecrosis of the femoral head. A multicentre study.

Six major and seven minor diagnostic criteria have been developed by the Japanese Investigation Committee for osteonecrosis of the femoral head (ONFH). We have carried out a multicentre study to clarify these. We studied prospectively 277 hips in 222 patients, from six hospitals, who had ONFH and other hip pathology and from whom histological material was available. We identified five criteria with high specificity: 1) collapse of the femoral head without narrowing of the joint space or acetabular abnormality on radiographs, including the crescent sign; 2) demarcating sclerosis in the femoral head without narrowing or acetabular abnormality; 3) a 'cold-in-hot' appearance on the bone scan; 4) a low-intensity band on T1-weighted images (band pattern); and 5) evidence of trabecular and marrow necrosis on histological examination. With any combination of two of these criteria, the sensitivity and specificity of the diagnosis were 91% and 99%, respectively.

Adolescent↗

PubMed1999

[Experimental study on intraperitoneal administration of 5-fluorouracil for liver metastasis in comparison with intravenous administration].

We studied the effects of 5-fluorouracil intraperitoneal administration using mouse liver metastasis model. We inoculated 50 microliters Colon26 cell suspension into the spleen and resected it 15 min after cell inoculation under general anesthesia with Ketamine. Control group (n = 7) had no treatment. The intraperitoneal (i.p.) group (n = 8) and intravenous (i.v.) group (n = 7) underwent the treatment on the 2nd and 4th day after the operation. Experimental chemotherapies consisted of 1.5 ml 5-fluorouracil solution (50 mg/kg) for i.p. group and 0.2 ml 5-fluorouracil solution (50 mg/kg) for i.v. group. On the 14th day after the cell implantation, necropsies were performed. Deposits on mouse livers were counted and the mouse livers weighted. Counting of metastatic liver deposits revealed the number of deposits in the control group was 25.6 +/- 12.9, against 2.9 +/- 1.9 and 16.0 +/- 15.6, in the i.p. and i.v. group, respectively. Significant differences in the number of liver deposits were obtained between the control group and i.p. group, and between i.p. group and i.v. group (p < 0.05). The mean liver weight (mg)/mouse body weight (g) were 76.3 +/- 24.7 in the control group, 54.3 +/- 4.7 in the i.p. group and 60.0 +/- 12.7 in the i.v. group. A significant difference was observed only between the control group and the i.p. group (p < 0.05). I.p. administration of 5-fluorouracil was superior to i.v. administration for control of the liver metastasis. Moreover, the side effect by 5-fluorouracil i.p. treatment was milder than by i.v. therapy. We confirmed the effectiveness of 5-fluorouracil intraperitoneal chemotherapy for the potential liver metastasis and liver micrometastasis. Intraperitoneal chemotherapy is also useful for peritoneal seeding. We think intraperitoneal chemotherapy is a recommendable administration route for gastrointestinal malignancies.

Animals↗

PubMed1999

[Analysis of micronuclei induced under hyperthermic conditions in human lymphocyte culture by fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY) methods].

The spectral karyotyping (SKY) method is a novel molecular cytogenetic technique which simultaneously discerns entire chromosomes. In order to elucidate the origins of micronuclei induced under hyperthermic conditions in human lymphocyte culture, peripheral blood cells were cultured at 40 degrees C or 42 degrees C for 3-24 h, using the cytokinesis-block method with cytochalasin B. The induced micronuclei were identified by the fluorescence in situ hybridization (FISH) and SKY methods. At 42 degrees C for more than 6 h, the frequency of occurrence of micronuclei in binucleated cells rose with increasing incubation time. By the FISH method, 83.3% of micronuclei induced in 24 h culture at 42 degrees C were shown to be positive for the human centromeric probes. By the SKY method, each micronucleus induced under the hyperthermic conditions was identified unequivocally and shown to contain a specific chromosome. These results suggest that the micronuclei induced under the hyperthermic conditions in human lymphocyte culture contain chromosomes which do not migrate to the poles at the anaphase of the cell cycle because of the breakdown of the spindle apparatus.

Cells, Cultured↗

PubMed1999

[Hemodynamics at hepatoarterial infusion of 5-FU in a chronic renal failure patient maintained by hemodialysis].

The authors studied the hemodynamics of 5-FU hepatoarterial infusion in a colorectal cancer patient with multiple liver metastases, who had chronic renal failure maintained by hemodialysis. Under weekly high dose 5-FU hepatoarterial infusion (1,000 mg/m2, 5 hours), on a non-dialysis day, serum 5-FU concentration was 1,090 ng/ml just after the 5 h infusion, 391 ng/ml at 15 min, 217 ng/ml at 30 min, 47 ng/ml at 60 min, and < 4 ng/ml at 120 min after infusion. On a dialysis day it was 1,500 ng/ml just after infusion, 41 ng/ml at 15 min, 5 ng/ml at 30 min, and < 4 ng/ml at 60 and 120 min after infusion. A control group (n = 4), who had liver metastases from colorectal cancers and normal renal functions, showed 5-FU serum concentration of 987 +/- 384 ng/ml just after infusion, 226 +/- 117 ng/ml at 15 min, 18.5 +/- 5.8 ng/ml at 30 min, < 4 ng/ml at 60 and 120 min after infusion. The serum 5-FU concentration of the patient was maintained higher on non-dialysis days, while it decreased more rapidly on dialysis days than that of the control group. There were no clinical complications due to the weekly high dose 5-FU hepatoarterial infusion. Under the treatment of continuous 5-FU hepatoarterial infusion (500 mg/day), the serum 5-FU concentration of this patient was kept under 115 ng/ml. After hemodialysis, the concentration decreased. The serum 5-FU concentration of the control group (n = 4) was under 66 ng/ml. There were no side effects under the protocol of continuous 5-FU hepatoarterial infusion. 5-FU hepatoarterial infusion for liver metastasis was a safe treatment for a renal failure patient with hemodialysis.

Aged↗