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Biomedical subjects

R Takeuchi

Publications and source records attributed to R Takeuchi.

At least 19 recordsLinked to original sources
PubMed2003

Unicompartmental knee arthroplasty for osteoarthritis of the knee: remaining postoperative flexion contracture affecting overall results.

The success rate of unicompartmental knee arthroplasty has been variable, and controversy still surrounds its use. Achieving good functional results from this surgery may require understanding surgical principles, precise operative techniques, and careful patient selection. This paper evaluates clinical results and factors influencing postoperative knee function after unicompartmental knee arthroplasty. The follow-up assessment of 109 knees that underwent unicompartmental knee arthroplasty showed that 90 of 109 knees were classified as excellent or good (82.6%) using the Hospital for Special Surgery knee scoring system. In the excellent group (54 knees), 52% of the postoperative, standing femorotibial angles converged on a range of 170 degrees to 175 degrees with a mean of 174 degrees +/- 4 degrees. The knees with residual flexion contracture after surgery showed poorer clinical results. Therefore, complete elimination of the flexion contracture during surgery is considered mandatory.

Arthroplasty, Replacement, Knee↗
PubMed2002

Significance of magnetic resonance imaging in the diagnosis of nodular regenerative hyperplasia of the liver complicated with systemic lupus erythematosus: a case report and review of the literature.

Nodular regenerative hyperplasia of the liver (NRH), characterized by multiple hepatic nodules in the absence of fibrosis, is a rare but important complication of systemic lupus erythematosus (SLE) associated with non-cirrhotic portal hypertension. The diagnosis of NRH is based on the pathological examination, and radiological findings of NRH are poorly documented. We report a case of a 40-year-old woman with SLE complicated with NRH. Sixteen years after diagnosis of SLE, esophageal varices were incidentally found and diagnosis of portal hypertension due to NRH was made by magnetic resonance imaging (MRI) and confirmed by needle liver biopsy. Although MRI showed the lesions as significant nodules, neither computed tomography nor ultrasonography could demonstrate the nodules. However, serial MRI showed significant enlargement of the nodules for 2 years Because NRH may lead to portal hypertension with life-threatening variceral haemorrhage in patients with SLE, MRI is a useful, non-invasive examination to screen the patients for its presence and follow-up. We reviewed the literature regarding NRH in SLE and discuss the management of the affected patients.

Adult↗
PubMed2001

Iridium complex-catalyzed allylic amination of allylic esters.

Iridium complex-catalyzed allylic amination of allylic carbonates was studied. The solvent strongly affected the catalytic activity. The use of a polar solvent such as EtOH is essential for obtaining the products in high yield. The reaction of (E)-3-substituted-2-propenyl carbonate and 1-substituted-2-propenyl carbonate with pyrrolidine in the presence of a catalytic amount of [Ir(COD)Cl](2) and P(OPh)(3) (P/Ir = 2) gave a branch amine with up to 99% selectivity. Both secondary and primary amines could be used for this reaction. When a primary amine was used, selective monoallylation occurred. No diallylation product was obtained. The reaction of 1,1-disubstituted-2-propenyl acetate with amines exclusively gave an alpha,alpha-disubstituted allylic amine. This reaction provides an alternative route to the addition of an organometallic reagent to ketimines for the preparation of such amines. The reaction of (Z)-3-substituted-2-propenyl carbonate with amines gave (Z)-linear amines with up to 100% selectivity. In all cases, no (E)-linear amine was obtained. The selectivities described here have not been achieved in similar palladium complex-catalyzed reactions.

Journal Article↗
PubMed2001

Reliability of the transepicondylar line as a parameter of femoral axial alignment.

The purpose of this research was to determine the significance of the transepicondylar line as a parameter of femoral axial alignment. Standing full-length X-ray films of 124 knees of 91 patients (63 women, 28 men) with osteoarthritis, rheumatoid arthritis, or osteonecrosis were used in this study, in which the lateral angles formed by the femoral anatomical axis intersecting with the transepicondylar line (angle a'), horizontal line (angle b'), and femoral condylar line (angle r') were measured. The mean value of angle b' in knees with neutral alignment was significantly smaller than that in knees with varus alignment, and significantly larger than that in knees with valgus alignment; no significant difference was found in angle a'. Also, there was no significant difference in angle a' among the patients with osteoarthritis, rheumatoid arthritis, and osteonecrosis. These findings suggest that the transepicondylar line, which is a stable reference of femoral rotation, is also a very reliable parameter of axial alignment of the femur. In the future design of extramedullary guiding for total knee arthroplasty, the transepicondylar line may play an important role as a parameter for proper and accurate implant setting.

Adult↗
PubMed2001

Effects of collagen gel mixed with hydroxyapatite powder on interface between newly formed bone and grafted achilles tendon in rabbit femoral bone tunnel.

The Achilles tendon was implanted into a bone tunnel made in the femoral condyle of 20 rabbits. In the left femur, collagen gel mixed with hydroxyapatite powder (C-HAp) was injected between the graft and the bone tunnel. On the other hand, as a control, simple saline was injected in the right femur. Five rabbits were sacrificed at 4, 8, 12, and 16 weeks after surgery. Histological findings showed that in the C-HAp group, the grafted tendon came in direct contact with new bone, and Sharpey-like collagen fibers arising from the grafted tendon were observed to penetrate new bone by 4 weeks after surgery. In the control group, however, fibrous tissue was observed between new bone and the grafted tendon, but no penetrating fibers from the grafted tendon into the new bone were observed until 16 weeks. The area of new bone in the C-HAp group was significantly greater than that in the control group 4, 8, and 12 weeks after surgery (p < 0.0001, p < 0.0007, p < 0.0013, respectively).

Achilles Tendon↗
PubMed2001

Treatment of the unstable distal radius fracture with external fixation and a hydroxyapatite spacer.

A prospective study was performed on 25 patients (15 women, 10 men) with unstable fractures of the distal radius selectively treated with a dynamic type of external fixation combined with a hydroxyapatite spacer. The fractures ranged from type VI to type VIII according to Frykman's classification. The patients' mean age at surgery was 49 years (range, 19-75 years). The mean follow-up period was 2.5 years, and overall outcome was assessed using Gartland and Werley's demerit point system as modified by Sarmiento. Radial inclination was 26 degrees +/- 4 degrees at the time of reduction and 26 degrees +/- 5 degrees at follow-up, palmar tilt was 9 degrees +/- 2 degrees at reduction and 8 degrees +/- 3 degrees at follow-up, and ulnar variance was 1.4 +/- 0.6 mm at reduction and 2.1 +/- 0.9 mm at follow-up. The mean range of motion at follow-up was 80 degrees +/- 10 degrees in flexion, 80 degrees +/- 10 degrees in extension, 85 degrees +/- 10 degrees in supination, and 80 degrees +/- 5 degrees in pronation. The outcome in 24 of 25 patients was evaluated as excellent. In the surgical treatment of unstable fractures of the distal radius using external fixator, the fracture reduction should be supported with bone graft or a bone substitute, and a hydroxyapatite spacer was considered to be a useful substitute for a bone graft.

Adult↗
PubMed2001

[Destructed knee in patient with systemic lupus erythematosus treated with total knee arthroplasty: a case report].

We reported a case of a 61-year-old female with arthritis of right knee associated with systemic lupus erythematosus (SLE). She suffered from SLE at age 31 and felt pain around her right knee at age 60. It gradually increased despite intraarticular injections of steroid and arthroscopic synovectomy. On admission, the range of motion of her right knee was 20 to 135 degrees and remarkable gait disturbance were noted due to the pain. Radiographs of the right knee showed joint space narrowing and bone erosion. YMCK total knee arthroplasty was performed. Operation findings showed smooth and thick synovium and cartilage defect. Histological examination revealed fibrin on surface, proliferad connective tissue and newly development of vasculature. Synovium eroded both cartilage and bone. In SLE, soft tissue contructure was reported to be a main cause of joint dislocation, but there were only a few report of progressive joint destruction due to SLE. In this case, the main cause of joint destruction may be invasion synovium into cartilage and bone.

Arthritis↗
PubMed2000

Coagulation and fibrinolytic activities in 2 siblings with beta(2)-glycoprotein I deficiency.

beta(2)-Glycoprotein I (beta(2)GPI) is a major antigen for antiphospholipid antibodies, and its multiple in vitro functions have been reported. This glycoprotein not only down-regulates thrombin formation by inhibiting contact activation or prothrombinase activity, but also up-regulates coagulation by reducing protein C anticoagulant activity. However, the in vivo roles of beta(2)GPI remain obscure. Coagulation and fibrinolytic characteristics were investigated in individuals with beta(2)GPI deficiency. An apparently healthy woman and her brother are homozygotes for beta(2)GPI deficiency. In these patients, Russell viper venom time was shortened (40.4 seconds; normal range, 47.8 +/- 4.95 seconds), but all markers of thrombin generation and fibrin turnover were within normal ranges. Exogenous activated protein C adequately prolonged the clotting time of the beta(2)GPI-deficient plasma, and euglobulin lysis time was also normal. Thus, elevated thrombin generation, enhancement of activated protein C response, and an altered fibrinolytic system were not found in congenitally beta(2)GPI-deficient plasma. (Blood. 2000;96:1594-1595)

Adult↗
PubMed2000

beta(2)-glycoprotein I deficiency: prevalence, genetic background and effects on plasma lipoprotein metabolism and hemostasis.

beta(2)-glycoprotein I (beta(2)-GPI=apolipoprotein H) is an important autoantigen in patients with the antiphospholipid syndrome. It also plays a role in lipoprotein metabolism, such as anti-atherogenic property, triglyceride removal, and enhancement of lipoprotein lipase. Serum beta(2)-GPI concentration of 812 apparently healthy Japanese individuals was measured by sandwich EIA. Two families with complete beta(2)-GPI deficiency were identified. In one family, all affected had increased serum LDL-cholesterol levels or smaller particle sizes of LDL, while the other had no apparent abnormality in lipid metabolism. Individuals investigated had no history of thrombosis or overt abnormalities in hemostatic tests. A thymine corresponding to position 379 of the beta(2)-GPI cDNA was deleted in every beta(2)-GPI deficient individual. The incidence of this heterozygous deficiency determined by RFLP was 6. 3% in Japanese and none in Caucasians. Heterozygotes had significantly lower concentrations of serum beta(2)-GPI than did those without the mutation, yet no significantly different lipid profiles, such as total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, apoA-I, apoB and Lp(a), were observed. A low concentration of beta(2)-GPI seemed not to be associated with apparent abnormality in lipoprotein metabolism.

Adult↗
PubMed2000

Anaerobic transformation of chlorophenols in methanogenic sludge unexposed to chlorophenols.

Transformation of all 19 chlorophenol (CP) isomers was investigated in a laboratory anaerobic methanogenic sludge that had not been exposed to synthetic chemicals. Concentration of CP was analyzed over time to calculate disappearance rate constants using first-order reaction kinetics and all possible CP degradation pathways were estimated. The rate constants ranged between 0.46 x 10(-3) and 0.161 day(-1). CPs were transformed via dechlorination. The chlorine atom at the ortho-position was the most easily dechlorinated, whereas dechlorination rate at the para-position was lowest. The overall pathways of CP transformation were much less diverse than that we previously found for contaminated sediment. The Dolfing hypothesis of microbial selection of the most thermodynamically favorable pathways was not applicable for CP transformation in this study as well as previous study performed by our group.

Anaerobiosis↗
PubMed2000

Recent increase in the frequency of infant measles in Japan.

BACKGROUND: Because there has been no major outbreak of measles in Japan during the last decade, subclinical boosting of pre-existing immunity by exposure to epidemic measles is unlikely to have occurred. Consequently, the measles immunity of mothers of this generation is less well developed and they provide less effective passive immunity to their infants. An increase in the frequency of infant measles is therefore probable. METHOD AND RESULTS: A retrospective review was undertaken of the clinical records of all measles cases that occurred in the last 3 years in eight hospitals and two out-patient clinics in Hokkaido. Of 541 recorded cases, 96 (17.7%) were infants and of these, 66 patients (68.8%) were over 9 months of age. Only 20 children had received measles vaccination. CONCLUSION: There has been a recent increase in the frequency of infant measles, suggesting an increased population of infants susceptible to measles before the age of 1. Of the older patients, 95% had not been vaccinated against measles. Increasing the rate of measles vaccination may help suppress future measles outbreaks and assist in protecting infants until they pass their first birthday.

Adolescent↗
PubMed2000

Effects of beta2-glycoprotein I and monoclonal anticardiolipin antibodies on extrinsic fibrinolysis.

Antiphospholipid antibodies (aPLs) are associated with an increased incidence of thrombosis, but the mechanisms responsible for thrombosis are unclear. The present study investigated the effect of both beta2-glycoprotein I (beta2-GPI) and aPLs on the activity of extrinsic fibrinolysis. The remaining tissue-plasminogen activator (t-PA) of the sample consisting of beta2-GPI, two-chain recombinant t-PA, plasminogen activator inhibitor (PAI) -1 was measured by a chromogenic assay using synthetic substrate S-2251, Glu-plasminogen, and soluble fibrin monomer. Without PAI-1, beta2-GPI did not affect t-PA activity. When 14.3 ng/ml PAI-1 was added to 3.6 U/ml t-PA, the remaining t-PA activity was increased from 48.9% to 60.4% by the addition of beta2-GPI (190 microg/ml). The effect of beta2-GPI did not require phospholipids. The beta2-GPI seems to protect t-PA activity from the inhibition by PAI-1. When monoclonal anticardiolipin antibodies (aCLs), EY1C8, and EY2C9, which were established from a patient with antiphospholipid syndrome, were further added to the mixture with a diluted phospholipid (Platelin) to investigate the influence of aPL, the remaining t-PA activity decreased to 50.1 and 80.7%. Monoclonal aCLs appeared to inhibit the effect of beta2-GPI, that is, these monoclonals inhibited the fibrinolytic activity by an elevation in PAI-1 activity. These results suggest the possibility that the impairment of fibrinolytic activity by aCLs is one of reasons for the increased incidence in thrombosis in patients with aCLs.

Antibodies, Anticardiolipin↗
PubMed2000

Possible contaminant origins of the red cosmetics decorating ancient burial sites in Japan.

Marker elements were estimated from the red cosmetics collected from different ancient burials and mine ruins in three separate districts of Japan. Element levels were displayed in reference to the relative amount to sulfur (RA/S), by which the cosmetics were divided into five types: I--a low Hg/S with a low Fe/S; II--both moderate Hg/S and Fe/S; III--a moderate Hg/S with a high Fe/S; III 2--a high Hg/S with a moderate Fe/S; IV--a high Hg/S with a high Fe/S. The cosmetics can be further characterized by referring to other contaminants such as Zn, Cu, and Mn. These combined analyses with contaminant metals were capable of characterizing the origins of the cosmetics; it is useful to compare them to each other. The cosmetics were identified as being due to several groups of contaminants from ancient mines in Japan, and also with this system analysis of the markers it is possible to identify them from neighboring countries.

Archaeology↗