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Biomedical subjects

Koji Hattori

Publications and source records attributed to Koji Hattori.

At least 19 recordsLinked to original sources
PubMed2006

High tibial osteotomy that does not cause recurrence of varus deformity for medial gonarthrosis.

It is widely accepted that high tibial osteotomy (HTO) is an effective surgical treatment for medial gonarthrosis. However, long-term follow-up studies have revealed that the clinical results deteriorate over time and varus deformity often recurs. We performed barrel-vault osteotomy in HTO with a correction angle that did not cause arthritic progression in the medial compartment of the knee or recurrence of varus deformity. Thirty patients (44 knees) were followed clinically and radiographically for a minimum of 10 years (average, 11.4 years). We aimed for an average postoperative femorotibial angle (FTA) of 165.3 degrees (range, 162-169 degrees ) according to our method using a correction angle chosen on the basis of the so-called Mikulicz's mechanical axis. The clinical results were good in 30 (68.2%) knees, fair in 7 (15.9%) and poor in 7 (15.9%). Arthritic progression in the medial compartment was only found in 1 (2.3%) knee, while in the lateral compartment it was found in 17 (38.6%) knees. Of the knees with arthritic progression in the lateral compartment, six (35.3%) were classified as poor. The average postoperative FTAs were 164.3 degrees at 1 year, 164.0 degrees at 5 years and 163.5 degrees at 10 years after the operation, indicating that the knees tended to become slightly valgus over time. The clinical results were not poor after slightly overcorrected osteotomy was performed. Since overcorrection tended to occur, when the preoperative lateral tibial thrust was severe, HTO is not a good indication for such cases.

Adult↗
PubMed2006

Mycotic aneurysm of the distal aortic arch caused by Aspergillus.

We describe an unusual case of a thoracic aortic aneurysm caused by Aspergillus. A 70-year-old man underwent prednisolone and Ara-C treatments for a myelodysplastic syndrome. Blood examination revealed pancytopenia. Under these treatments, an aneurysm presented at the distal aortic arch. He underwent resection of the aneurysm with a graft repair covered by a pedicled omentum flap, followed by prolonged administration of micafungin and itraconazole for a mycotic aneurysm. The postoperative course was favorable without complications. Serum C-reactive protein became negative and he was discharged 2 months after the surgery. However, 4 months after the surgery, he died from worsening of the myelodysplastic syndrome. The prognosis for patients with mycotic aneurysms is poor due to their immunocompetent condition arising from underlying diseases. Therefore, in addition to prompt treatment with antifungal agents combined with surgical debridement, control of the underlying disease is essential for improving the outcome.

Aged↗
PubMed2006

Treatment of Kienböck's disease with cultured stem cell-seeded hybrid tendon roll interposition arthroplasty: experimental study.

BACKGROUND: Several procedures that consist of excision arthroplasty, intercarpal arthrodesis with or without excision of the lunate, proximal row carpectomy, and joint leveling procedures are used to treat advanced Kienböck's disease. However, no reconstructive surgery for a collapsed lunate has been established. The aim of this study was to develop a method of tendon roll interposition arthroplasty using a tissue-engineering technique to improve the clinical results of the tendon roll interposition arthroplasty for treating advanced Kienböck's disease. METHODS: Twenty-four Japanese white rabbits were used for this study as three treatment models of Kienböck's disease. The lunate of the right paw was excised, and then one of three kinds of tendon roll was interposed into the excision space as follows: group A (controls), a conventional tendon roll made of autologous Achilles tendon; group B (cored tendon roll) a tendon roll with a core of the collagen-ceramic composite; and group C (hybrid tendon roll), a scaffold seeded with cultured cells was rolled in the Achilles tendon. In all groups the right wrist was immobilized with cast 6 weeks after surgery. Wrist radiography was evaluated 0, 4, 6, and 12 weeks after surgery; specimens were sectioned and evaluated histologically 12 weeks after surgery. RESULTS: In group C the small shadow of the hydroxyapatite granule gradually increased until 12 weeks after surgery, whereas in group B the shadow of the core gradually decreased. The deficit spaces of the lunate remained radiographically lucent for 12 weeks after surgery in group A. Histological findings revealed new bone formation at the center and stained cartilage matrix at the peripheral of the hybrid tendon roll group (group C) but not in group A or B. CONCLUSIONS: Radiological and histological examinations proved that it is possible to make new hybrid tendon rolls using this method, as osteogenesis in the center and cartilage matrix in the peripheral of the tendon roll were revealed.

Animals↗
PubMed2006

Long-term clinical and radiographic follow-up of total resection for discoid lateral meniscus.

PURPOSE: The purpose of this retrospective study was to analyze the effects of age at surgery on the clinical results, arthritic progression, and changes in lower limb alignment during long-term follow-up of total resection for discoid lateral meniscus. METHODS: A total of 37 knees in 32 patients were reviewed as a whole group and also after division into the following 3 groups according to the age at surgery: group A, 11 knees in patients aged less than 20 years; group B, 13 knees in patients aged 20 to 39 years; and group C, 13 knees in patients aged greater than 39 years. The mean age at surgery was 31.2 years (range, 9 to 52 years), and the mean length of follow-up was 14.5 years (range, 10 to 22.4 years). RESULTS: According to the scale of Ikeuchi, clinically excellent or good results at the final follow-up were found in 84% of the knees in the whole group, 91% of those in group A, 85% of those in group B, and 77% of those in group C. Moderate or severe narrowing of the lateral joint space was seen in 11% of the knees in the whole group, 0% of those in group A, 8% of those in group B, and 23% of those in group C. In an analysis of lower limb alignment, statistically significant postoperative lateral shifts of Mikulicz's mechanical axis were observed in groups B and C. CONCLUSIONS: The clinical results were satisfactory and the postoperative arthritic changes were mild in patients aged under 40 years. However, it is necessary to carefully monitor arthritic progression in patients who are aged over 19 years and have valgus deformities, because most of the knees in patients above this age became more valgus postoperatively. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Adolescent↗
PubMed2006

Rapid preparation of fresh frozen tissue-engineered bone sections for histological, histomorphological and histochemical analyses.

Fresh frozen sections are the best materials to assess tissue-engineered bone using cells/ceramic complexes. However, there are a lot of technical difficulties in obtaining serial sections suitable for microscopic examinations. Kawamoto et al. developed a method for the production of fresh frozen sections using new adhesive tape, and showed that sections were very useful for histological and histochemical studies. However, no study reported that the method was useful for tissue-engineered bone from histochemical and histomorphological points of view. This study aimed to determine the efficacy of fresh frozen sectioning for evaluating tissue-engineered bone. We revealed that fresh frozen sections retained the original morphology of tissue-engineered bone, and their biochemical characteristics. Therefore, rapid preparation of fresh frozen sections using adhesive tape is extremely useful for research of tissue-engineered bone, and serial sections can be assessed from both histomorphological and biochemical point of views. It is expected that this method will become a powerful tool in tissue-engineering of hard tissues.

Animals↗
PubMed2005

Evaluation of the effect of collagen network degradation on the frictional characteristics of articular cartilage using a simultaneous analysis of the contact condition.

BACKGROUND: Superficial conditions and integrity of collagen network play an important role on the lubrication performance of articular cartilage. In this work, a technique based on the evanescent waves is used for the evaluation of contact condition during friction tests. METHODS: The frictional and superficial characteristics of the normal and degraded articular cartilages with high and low concentration of collagenase were evaluated. The optical apparatus was set in order to decrease the intensity of a light reflected at the interface between a prism and specimens when collagen fibers are found near the interface. FINDINGS: For all conditions, an increase in the attenuation of reflectance as the friction coefficient increases was observed with reasonable correlation. For the specimens degraded with collagenase, low friction and reduced attenuation of reflectance were observed at the beginning of sliding followed by a gradual increase in both friction and attenuation of reflectance. In comparison to the degraded specimens, normal specimens presented high friction at beginning and low friction at the end of test. INTERPRETATION: The superficial conditions and the presence of water at the articular surface play an important role in the lubrication of synovial joints. The ability to retain water for degraded specimens is impaired due to the loss of proteoglycan observed in the histological sections and hence, their low friction observed at the beginning of the test is not sustained for a long time. The use of evanescent waves demonstrated to be very useful in the analysis of the contact condition of articular cartilage.

Animals↗
PubMed2005

Evaluation of the superficial characteristics of articular cartilage using evanescent waves in the friction tests with intermittent sliding and loading.

Articular cartilage plays an important role in the lubrication of synovial joints because of its peculiar characteristics. In this work, the frictional and superficial characteristics of articular cartilage were evaluated simultaneously during intermittent sliding and loading. The apparatus used for the analysis of the articular surface was based on the evanescent waves, where a laser light was reflected at the interface between a prism and a specimen of articular cartilage. Friction forces were measured due to the sliding of specimens on the prism. Images of reflected light were analyzed and attenuation of the reflectance was associated with the presence of collagen fibers near the interface, which interacted with the evanescent waves because of the high refractive index of these fibers. Specimens were tested in the intervals of 5.5 min with an interruption of 10 and 30 s in the sliding and loading. Results indicated a decrease in the both friction coefficient and attenuation of reflectance after the unloading. The level of reduction of the friction as well as of the attenuation of reflectance increased as the time of unloading increased. Decrease of friction after unloading was related to the decrease of collagen contents, or increase in water contents, at the articular surface, which was observed through the decrease of the attenuation of reflectance. Results indicated that the increase in the water content at the articular surface and the rehydration ability of articular cartilage after unloading could be responsible for the maintenance of friction in low levels.

Animals↗
PubMed2005

Quantitative ultrasound can assess the regeneration process of tissue-engineered cartilage using a complex between adherent bone marrow cells and a three-dimensional scaffold.

Articular cartilage (hyaline cartilage) defects resulting from traumatic injury or degenerative joint disease do not repair themselves spontaneously. Therefore, such defects may require novel regenerative strategies to restore biologically and biomechanically functional tissue. Recently, tissue engineering using a complex of cells and scaffold has emerged as a new approach for repairing cartilage defects and restoring cartilage function. With the advent of this new technology, accurate methods for evaluating articular cartilage have become important. In particular, in vivo evaluation is essential for determining the best treatment. However, without a biopsy, which causes damage, articular cartilage cannot be accurately evaluated in a clinical context. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the cartilage are measured by introducing an ultrasonic probe during arthroscopy of the knee joint. The purpose of the current study was to determine the efficacy of this ultrasound system for evaluating tissue-engineered cartilage in an experimental model involving implantation of a cell/scaffold complex into rabbit knee joint defects. Ultrasonic echoes from the articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the percentage maximum magnitude (the maximum magnitude of the measurement area of the operated knee divided by that of the intact cartilage of the opposite, nonoperated knee; %MM) was used as a quantitative index of cartilage regeneration. Using this index, the tissue-engineered cartilage was examined to elucidate the relations between ultrasonic analysis and biochemical and histological analyses. The %MM increased over the time course of the implant and all the hyaline-like cartilage samples from the histological findings had a high %MM. Correlations were observed between the %MM and the semiquantitative histologic grading scale scores from the histological findings. In the biochemical findings, the chondroitin sulfate content increased over the time course of the implant, whereas the hydroxyproline content remained constant. The chondroitin sulfate content showed a similarity to the results of the %MM values. Ultrasonic measurements were found to predict the regeneration process of the tissue-engineered cartilage as a minimally invasive method. Therefore, ultrasonic evaluation using a wavelet map can support the evaluation of tissue-engineered cartilage using cell/scaffold complexes.

Animals↗
PubMed2005

Differential acoustic properties of early cartilage lesions in living human knee and ankle joints.

OBJECTIVE: Although numerous studies have been performed to determine whether there are histologic, biochemical, biomechanical, and metabolic differences between knee and ankle cartilage, none have investigated the presence of such differences in living human cartilage. We previously developed an ultrasonic evaluation system for articular cartilage that analyzes the A-mode echogram using wavelet transformation. The current study was undertaken to determine whether the acoustic properties of living human cartilage differ between knee and ankle joints. METHODS: Twenty-eight patients were subjected to ultrasonic evaluation under arthroscopy. After arthroscopic grading, the cartilage was measured using an ultrasonic probe. Two quantitative parameters were used, i.e., the maximum magnitude and the echo duration at the 95% interval of the maximum magnitude. RESULTS: In intact cartilage, the maximum magnitude and echo duration did not differ between the knee and the ankle. In lesional cartilage, in contrast, the maximum magnitude was higher, and the echo duration was shorter, in the ankle than in the knee. These differences were statistically significant. CONCLUSION: Ultrasound findings could be used to judge the degree of early cartilage degeneration in vivo on the basis of objective data such as the maximum magnitude and echo duration. Because we were unable to quantitatively analyze the biochemical and biomechanical properties of the cartilage in this study, our biochemical and biomechanical findings are based only on qualitative assessment. Nevertheless, the results indicate that this ultrasonic evaluation system may be useful for elucidating the processes of articular cartilage degeneration in osteoarthritis.

Acoustics↗
PubMed2005

Cartilage regeneration using mesenchymal stem cells and a three-dimensional poly-lactic-glycolic acid (PLGA) scaffold.

Cartilage engineered from mesenchymal stem cells (MSCs) requires a scaffold to keep the cells in the cartilage defect and to act as a support for inducing hyaline cartilage formation. We developed a novel three-dimensional special poly-lactic-glycolic acid (PLGA) scaffold that provided structural support and stimulated repair. Three-dimensional PLGA scaffolds seeded with cultured MSCs were transplanted into large defects in rabbit knees and analyzed histologically at 4 and 12 weeks after the operation. Our findings showed that in the engineered cartilage with the PLGA scaffold, the defects were filled with smooth, shiny white tissue macroscopically and hyaline-like cartilage histologically at 12 weeks after the transplantation. The structure of the novel PLGA scaffolds provided architectural support for the differentiation of progenitor cells and demonstrated successful induction of in vivo chondrogenesis.

Absorbable Implants↗
PubMed2005

Relationship between granulocyte elastase and C3a under protamine dosing in on-pump cardiac surgery.

OBJECTIVE: The complement cascade and granulocytes are activated in on-pump cardiac surgery. If activation of complement directly regulates granulocytes, granulocyte elastase (GEL) should increase significantly after protamine administration. We examined the effect of protamine on granulocytes by protamine administration and observation of the effect on GEL and C3a. METHODS: Thirty patients who underwent coronary artery bypass grafting were randomly assigned to two groups. In 15 patients, protamine was administered 5 min after the termination of cardiopulmonary bypass, and was administered 35 min after cardiopulmonary bypass in the other 15 patients. All patients were perfused with heparin-coated circuits and received 300 IU/kg heparin and 3 mg/kg protamine. GEL and C3a concentrations were measured at 7 time points. RESULTS: GEL concentrations increased significantly just before aortic declamping and did not increase significantly after protamine administration. C3a concentrations, however, did not increase during cardiopulmonary bypass and did increase significantly after protamine administration. CONCLUSIONS: This study indicates that GEL does not increase after protamine administration and that complement concentration does not directly affect GEL release.

Aged↗
PubMed2005

Novel ultrasonic evaluation of tissue-engineered cartilage for large osteochondral defects--non-invasive judgment of tissue-engineered cartilage.

Although numerous methods for regenerating articular cartilage have been investigated, the regenerated tissue showed various histological findings from hyaline-like cartilage to fibrous tissue. Without biopsy, we are unable to know whether the cartilage regeneration method was histologically successful or not. We developed a new ultrasonic evaluation system for articular cartilage using the maximum magnitude (MM) from ultrasonic analysis. The purpose of this study was to investigate the usefulness of ultrasonic judgment of the cartilage regeneration procedure. Using our system we quantitatively evaluated tissue-engineered cartilage in rabbit cartilage defects. The specimens were retrospectively divided into two groups on the basis of histological findings and investigated whether significant differences in ultrasonic analysis could be found between the two (group H: hyaline-like cartilage group, successful; group F: fibrous tissue group, failure). In the ultrasonic findings, the MM was 1.11+/-0.32 in group H and 0.65+/-0.18 in group F and these differences were significant (P=0.00061). Our results suggest that the ultrasonic evaluation system used in the present study is capable of judging the success or failure of cartilage regeneration procedures, and therefore, it could be a valuable tool arthroscopic diagnosis of cartilage regeneration.

Animals↗
PubMed2005

Contralateral meningeal artery supply of paramedian meningiomas.

BACKGROUND: When resecting at falcine or parasagittal portion of paramedian meningiomas, intraoperative hemostasis often is difficult despite effective management of ipsilateral meningeal arteries. We attribute such difficulties to meningeal artery blood supply from the contralateral side. We retrospectively studied feeding arteries from both sides in case of paramedian meningioma in terms of patient and tumor characteristics. METHODS: Forty-three patients with paramedian meningiomas underwent selective internal and external carotid angiography. We investigated how contralateral meningeal arterial feeders related to patient profiles and imaging, histopathologic, and immunohistochemical findings. RESULTS: Contralateral meningeal supply existed for 14 of 25 falcine meningiomas and 6 of 18 parasagittal meningiomas. Patients with contralateral feeders were 8.5 years younger than the others (P=.027) and were more likely to have larger tumors (P=.028). These were histopathologically malignant (P=.048), while showing more proliferation followed by monoclonal antibody against the Ki-67 antigen index (P=.012) and angiogenetic potential associated with vascular endothelial growth factor expression (P=.0085). CONCLUSIONS: Contralateral meningeal supply may reflect strong angiogenetic recruitment from rapid tumor growth followed by high expression of vascular endothelial growth factor. This angiographical feature may predict the aggressive growth of paramedian meningiomas.

Adult↗
PubMed2005

[Surgical treatment for chronic pulmonary thromboembolism].

Chronic pulmonary thromboembolism is a serious disorder because hypoxemia and pulmonary hypertension progress, finally resulting in respiratory and right-side heart failures. We evaluated the results of surgical treatment in patients in whom circulatory arrest was induced under profound hypothermia. Between 1995 and April 2004, 89 cases were surgically treated. The pathologic condition of these patients was classified as being degree III or greater in the NYHA classification. Following a median sternotomy, profound hypothermia was induced using cardiopulmonary bypass, and pulmonary thromboendarterectomy in the bilateral pulmonary arteries was performed under intermittent circulatory arrest. Of the 89 patients, 4 of 5 who underwent emergent surgery died after postoperatively. Among 84 patients who underwent elective surgery, 7 died of respiratory and cardiac failure. Clinical symptoms were markedly improved by surgery in 73 patients. Because this disease is resistant to medical treatment, pulmonary thromboendarterectomy using intermittent circulatory arrest under profound hypothermia is effective in treating patients with chronic thromboembolic pulmonary hypertension.

Chronic Disease↗
PubMed2005

Bio-artificial periosteum for severe open fracture--an experimental study of osteogenic cell/collagen sponge composite as a bio-artificial periosteum.

In an attempt to reduce complications in cases of severe open fracture, we developed a bio-artificial periosteum composed of osteogenic cells and collagen sponge. In the present study, we evaluated the osteogenic potential of the bio-artificial periosteum in vivo and in vitro. After 4-week incubation in vitro, the bio-artificial periosteum had high alkaline phosphatase activity and osteocalcin content. Moreover, energy dispersive X-ray analysis revealed numerous crystal structures consisting of P and Ca on the surface of the bio-artificial periosteum. Using a rat model for severe bone injury, we examined the bone formation process in defect sites covered with the bio-artificial periosteum. New bone formation occurred in the central part of the bone defect as well as at the bone edge. We conclude that by using the bio-artificial periosteum, the fracture site benefited from an improved osteogenic environment. These results indicate that a clinical trial to further evaluate this technique should be conducted.

Alkaline Phosphatase↗
PubMed2005

Stimulatory effects of statins on bone marrow-derived mesenchymal stem cells. Study of a new therapeutic agent for fracture.

Recent studies have reported that statins, inhibitors of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase, increase bone formation in osteoblasts in vitro, suggesting that statins may have a new therapeutic application in the treatment of osteoporosis. During the reparative phase of healing of bone fractures, bone marrow-derived mesenchymal stem cells differentiate into osteoblasts or chondrocytes to form callus. If statins also stimulate bone formation in bone marrow-derived mesenchymal stem cells they may have beneficial effects in the treatment of bone fractures. In this study, we assessed the effect of statins on bone formation in rat bone marrow-derived mesenchymal stem cells in vitro. The statins fluvastatin, simvastatin and pravastatin did not significantly enhance mineralization, alkaline phosphatase (ALP) activity and bone gra protein (BGP, osteocalcin). These findings suggest that statins do not increase bone formation in bone marrow-derived mesenchymal stem cells.

Animals↗
PubMed2004

Quantitative ultrasonic assessment for detecting microscopic cartilage damage in osteoarthritis.

Osteoarthritis (OA) is one of the most prevalent chronic conditions. The histological cartilage changes in OA include surface erosion and irregularities, deep fissures, and alterations in the staining of the matrix. The reversibility of these chondral alterations is still under debate. It is expected that clinical and basic science studies will provide the clinician with new scientific information about the natural history and optimal treatment of OA at an early stage. However, a reliable method for detecting microscopic changes in early OA has not yet been established. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the articular cartilage are measured by introducing an ultrasonic probe into the knee joint under arthroscopy. The purpose of this study was to assess microscopic cartilage damage in OA by using this cartilage evaluation system on collagenase-treated articular cartilage in vivo and in vitro. Ultrasonic echoes from articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the maximum magnitude and echo duration were selected as quantitative indices. Using these indices, the articular cartilage was examined to elucidate the relationships of the ultrasonic analysis with biochemical, biomechanical and histological analyses. In the in vitro study, the maximum magnitude decreased as the duration of collagenase digestion increased. Correlations were observed between the maximum magnitude and the proteoglycan content from biochemical findings, and the maximum magnitude and the aggregate modulus from biomechanical findings. From the histological findings, matrix staining of the surface layer to a depth of 500 mum was closely related to the maximum magnitude. In the in vivo study, the maximum magnitude decreased with increasing duration of the collagenase injection. There was a significant correlation between the maximum magnitude and the aggregate modulus. The evaluation system therefore successfully detected microscopic changes in degenerated cartilage with the use of collagen-induced OA.

Algorithms↗