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Biomedical subjects

Y Uchio

Publications and source records attributed to Y Uchio.

At least 37 records · Page 2Linked to original sources
PubMed2000

Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients.

We present a new surgical technique of anterior cruciate ligament (ACL) augmentation using autogenous hamstring tendons or allogenic fascia lata under arthroscopy for patients in whom considerable ACL remnants with mechanoreceptors are preserved. We review the clinical results of 40 patients who underwent this ACL augmentation, as assessed by manual instability tests, KT-2000 knee arthrometer, Lysholm and Gillquist score, joint position sense and magnetic resonance imaging (MRI), and compare them with those of ACL reconstruction. The side-to-side differences of anterior displacement measured by the KT-2000 knee arthrometer at 30 lbs, an average of 5.3 +/- 2.6 mm preoperatively, was significantly improved to an average of 0.7 +/- 1.8 mm in the augmentation group, while an average of 6.0 +/- 2.4 mm was improved to 1.8 +/- 2.1 mm in the reconstruction group. There was no statistically significant difference between the preoperative values in the two groups, but the postoperative values of the augmentation group were significantly less than those of the reconstruction group. The ratio of anterior terminal stiffness of the augmentation group was 1.2 +/- 1.8, and that of the ACL reconstruction group was 0.7 +/- 0.4. This was a statistically significant difference (P < 0.05). Thus, as for the KT-2000 knee arthrometer, the ACL augmentation group showed significantly better anteroposterior stability and terminal stiffness than the ACL reconstruction group. The final inaccuracy of joint position sense of the augmentation group was 0.7 degrees +/- 0.7 degrees, while that of the reconstruction group was 1.7 degrees +/- 1.2 degrees indicating a significant difference (P < 0.05). This study demonstrates that ACL augmentation, which can preserve ACL remnants with mechanoreceptors, is superior to ACL reconstruction from the viewpoint of position sense and joint stability.

Adolescent↗
PubMed2000

Adverse effects of saline neurolysis on a chronically compressed rat sciatic nerve.

We have evaluated the effect of saline neurolysis compared with a simple decompression procedure on chronically compressed sciatic nerves in rats. Eight months after the initiation of nerve compression within a silicone tube, rats were divided into three groups of 35. In group I, saline was injected subepineurially at the compressed segment of the nerve after removal of the tube (decompression plus saline neurolysis). The nerves in group II were treated by removal of the tube only (simple decompression). In group III the tubes were left in place. Adding saline neurolysis to decompression provided no histological, morphometric, electrophysiological, or vascular advantages up to four months, and even gave worse results than simple decompression. We conclude that saline neurolysis has no beneficial effect on a chronically compressed nerve and it is not recommended for clinical use.

Animals↗
PubMed2000

Proprioceptive improvement in knees with anterior cruciate ligament reconstruction.

The correlation between the prospective course of proprioceptive improvement and knee stability after anterior cruciate ligament reconstruction was investigated in 38 patients. Proprioception, on the basis of the patient's capacity to reposition the limb accurately, was evaluated at 3-month intervals for 24 months after hamstring graft anterior cruciate ligament surgery. Knee stability was evaluated concurrently with a KT-2000 knee arthrometer. Thirty patients experienced improvement in postoperative position sense in at least one of the examinations, although eight patients had no improvement at any time. Of the 30 patients who had improvement, 28 maintained improved position sense from 18 months to the final followup. Thirty patients maintained significantly better knee stability for a postoperative period of at least 24 months. These results indicated that a minimum of 18 months after anterior cruciate ligament reconstruction may be needed for complete restoration of the proprioceptive function in knees, although the mean position sense in all patients gradually improved from 9 months. Improvement in postoperative knee stability may have facilitated recovery of proprioception.

Adolescent↗
PubMed2000

Effectiveness of an insole with a lateral wedge for idiopathic osteonecrosis of the knee.

For the purpose of investigating the effect of an insole with a lateral wedge, we studied 30 patients (31 knees) aged from 46 to 78 years with idiopathic osteonecrosis of the knee for at least three years. The 18 knees treated with an insole (group I) were matched by age, gender, obesity index, area of lesion, femorotibial angle, stage, and clinical evaluation with 13 treated conservatively without an insole (group II). The clinical results, as rated by a knee score, improved significantly more in group I than in group II. Radiologically, the necrotic area and ratio decreased in group I, whereas in group II they increased. In advanced cases, with stage 4 or a femorotibial angle of more than 180 degrees, the use of an insole did not improve the clinical or radiological findings. The insole is a valuable method of conservative treatment for the early stages of osteonecrosis of the medial femoral condyle.

Aged↗
PubMed1999

Unilateral sciatic nerve injury stimulates contralateral nerve regeneration.

Axonal outgrowth in tissue cultures was measured to determine whether unilateral peripheral nerve injuries affect contralateral nerve regeneration. The right sciatic nerves of young male Wistar rats were cut at mid-thigh level. Sham operation as a control was limited to the exposure of the nerve without cutting. At day 6 post-surgery, bilateral L5 dorsal root ganglia (DRG) with attached nerve stumps were resected and cultured. Axonal outgrowth from the nerve stump was measured in situ. The contralateral preparations showed longer outgrowths than controls. Therefore the conditioning effect was not merely restricted to the ipsilateral neurons but also affected undamaged sensory neurons of the contralaretal DRG.

Animals↗
PubMed1999

Hyaluronic acid enhances proliferation and chondroitin sulfate synthesis in cultured chondrocytes embedded in collagen gels.

The effects of hyaluronic acid (HA) on the proliferation and chondroitin sulfate (CS) synthesis of chondrocytes embedded in collagen gels were examined. Articular cartilage was isolated from the humerus, femur, and tibia of 21 10-week-old Japanese white rabbits. Chondrocytes isolated by collagenase digestion were embedded in type I collagen gels and cultured in Dulbecco's modified Eagle's medium (DMEM) with various doses of HA for 4 weeks. Histological and biochemical evaluations were performed at postculture weeks 1, 2, 3, and 4. For biochemical evaluations, isomers such as chondroitin 6-sulfate (delta(di)-6S) and chondroitin 4-sulfate (delta(di)-4S) synthesized by cultured chondrocytes were determined by high performance liquid chromatography (HPLC) combined with fluorometry. Morphological and histological studies demonstrated that HA-treated chondrocytes in collagen gel proliferated profusely while maintaining their phenotype. At postculture week 4, 0.1 mg/ml of HA induced an eightfold increase in cell counts compared with HA pretreatment values, or 1.5-fold more than control group. Synthesis of delta(di)-6S (delta(di)-6S content/cell) in groups treated with 0.01 and 0.1 mg/ml of HA significantly increased, while gel accumulation rates in groups treated with 0.1 and 1.0 mg/ml of HA scored significantly higher values than other groups. In collagen gel culture, HA enhanced the proliferation and delta(di)-6S synthesis of chondrocytes while maintaining their phenotype. In clinical application, since the supply of autologous chondrocytes for transplantation is not unlimited, the HA-treated culture method may be useful for increasing the number of chondrocytes and thus improving the quality of implants.

Animals↗
PubMed1999

Clinical significance of magnetic resonance imaging (MRI) for focal chondral lesions.

To evaluate the diagnostic potential of magnetic resonance imaging (MRI) and define its role, focal chondral lesions of the femoral surface of the tibiofemoral joint were examined. Full-thickness defects were well detected prospectively (93%) with conventional MRIs initially administered for observation reference of ligaments and menisci. Optimized MRIs, which included right-angled planes to the lesion surface and magnetization transfer contrast (MTC) sequences, delineated the size of lesions (R2 = 0.648,p < 0.0001) and the difference between full-and partial-thickness defects (88% in accuracy). A forward-tilt of 30 degrees to the femoral shaft was the average plane angle that afforded optimal visualization of the chondral lesions. Our findings advocate that routine MRIs are sufficient in detecting severe chondral lesions that require further examination, and the optimized images are highly useful in facilitating the recently developed therapeutic approaches and follow-up studies for articular cartilage defects.

Adolescent↗
PubMed1999

Meniscal rasping for repair of meniscal tear in the avascular zone.

We examined experimentally whether a longitudinal tear in the avascular zone of a rabbit meniscus can be healed by meniscal rasping. A full-thickness longitudinal tear 5-mm long was artificially created in the avascular zone of the anterior segment of both medial menisci. Meniscal rasping was then done on the femoral surface of the right meniscus from the parameniscal synovium to the inner segment including the tear. The left meniscus was left without further treatment as control. Two to 4 weeks after surgery, the hypertrophic synovium was observed invading from the parameniscal region to the injured portion. Eight to 16 weeks after surgery, the tear was almost completely healed. In contrast, neither hypertrophy of the synovium covering the tear nor healing was induced in the control meniscus. The mechanical test showed that there was a significant difference in the tensile strength and the stiffness of the injured portion between the rasped meniscus and the control meniscus. Meniscal rasping is easy to do, is effective, and causes few adverse effects with menisci. This procedure may be a treatment option for clinical cases of meniscal tear in the avascular zone for which we have no effective and clinically applicable methods at present, although further investigation is needed before clinical application.

Animals↗
PubMed1999

The time-dependent difference of GAP-43 expression between sensory neurons and motoneurons after peripheral nerve transection.

The L5 dorsal root ganglion (DRG) cells and L5 anterior horn (AH) cells of rats were studied and examined immunocytochemically after transection of the sciatic nerve to find out whether there would be time-dependent differences in the increase of growth-associated protein (GAP-43) expression between sensory neurons and motoneurons. On the seventh day after transection at mid-thigh level, the levels of GAP-43 in the DRG cells significantly increased, while those in the AH cells began to increase gradually from the 14th day onward. Transection at the piriform muscle level induced a significant increase in immunoreactivity of GAP-43 on the third day in the DRG cells, and on the seventh day in the AH cells. These results showed that sensory neurons expressed GAP-43 immunoreactivity earlier than motoneurons after peripheral nerve transection regardless of the site, suggesting that sensory neurons might start to produce cytoskeletons for axonal elongation earlier than motoneurons after nerve transection.

Analysis of Variance↗
PubMed1999

The regeneration of sensory neurones in the reconstruction of the anterior cruciate ligament.

We examined whether somatosensory evoked potentials (SEPs) were detectable after direct electrical stimulation of injured, reconstructed and normal anterior cruciate ligaments (ACL) during arthroscopy under general anaesthesia. We investigated the position sense of the knee before and after reconstruction and the correlation between the SEP and instability. We found detectable SEPs in all ligaments which had been reconstructed with autogenous semitendinosus and gracilis tendons over the past 18 months as well as in all cases of the normal group. The SEP was detectable in only 15 out of 32 cases in the injured group, although the voltages in the injured group were significantly lower than those of the controls. This was not the case in the reconstructed group. The postoperative position sense in 17 knees improved significantly, but there was no correlation between it and the voltage. The voltage of stable knees was significantly higher than that of the unstable joints. Our findings showed that sensory reinnervation occurred in the reconstructed human ACL and was closely related to the function of the knee.

Adolescent↗
PubMed1998

Sensory neurons regenerate more dominantly than motoneurons during the initial stage of the regenerating process after peripheral axotomy.

This study was designed to determine whether sensory neurons or motoneurons were dominant during the earlier stage of the regeneration process after peripheral axotomy. After transection of the right sciatic nerves of rats, epineurial end neurorrhaphy was performed. At 5, 7 and 14 days postoperatively, the nerves were re-transected at the positive pinch site, and their proximal stumps were exposed to the retrograde neurotracer, Fluoro-Gold (F-G). Seventy-two hours later, the lumbar spinal cords and the L4 and L5 dorsal root ganglia (DRG) were harvested and evaluated. The incidence and the intensity of F-G labelling in DRG were significantly higher than in anterior horns (AH). These results demonstrated that sensory neurons were more dominant than motoneurons in nerve regeneration.

Animals↗
PubMed1998

Anatomic bases of ankle arthroscopy: study of superficial and deep peroneal nerves around anterolateral and anterocentral approach.

We studied the anatomy of the anterolateral and anterocentral portal sites for ankle arthroscopy with reference to the superficial peroneal nerve (SPN) in 29 cadavers (51 ankles) and the deep peroneal nerve (DPN) in 11 cadavers (21 ankles). In relation to the level of division into the medial and intermediate cutaneous nerves and their terminal branches, we classified the structure of the SPN surrounding the ankle into five types. We also identified the point where the SPN and the DPN cross the level of the talocrural joint. 32% of specimens had different SPN division types on the two sides and there was an average of 2 nerves at the level of the talocrural joint. Branches of the SPN were found lateral to the edge of the peroneus tertius tendon in 11.8% of specimens, and at its lateral edge in 27.5%. The DPN and some branches of the SPN were positioned around the lateral edge of the extensor hallucis longus tendon. We consider that the anterolateral portal should be made at least 2 mm lateral to the peroneus tertius tendon to avoid injury to the SPN, since the diameter of the scope is 27 mm. The anterocentral portal is unsuitable for arthroscopy due to a high risk of injury to the DPN and branches of the SPN.

Aged↗
PubMed1998

Bilateral piriformis syndrome after total hip arthroplasty.

We present the case of a 39-year-old man with bilateral piriformis syndrome 4 and 6 years after two cementless total hip arthroplasties, respectively. During surgical exploration, each sciatic nerve was found to be entrapped by a tense piriformis muscle and hypertrophic posterior hip capsule. The sciatic-type pain was relieved after sectioning each piriformis muscle with external neurolysis. This is the first reported case of piriformis syndrome after total hip arthroplasty.

Adult↗
PubMed1998

A new guide system for posteromedial portal in arthroscopic knee surgery.

A view through the posteromedial portal is necessary to observe the posterior portion of the knee joint such as the tibial attachment of the posterior cruciate ligament (PCL) or the posterior horn of the medial meniscus, which is barely, visible through anterior portals. Especially in arthroscopic PCL reconstruction, the arthroscopic view through the posteromedial portal is indispensable for boring a tibial bone tunnel that is correctly sited. However, it is difficult to create this portal safely without cartilaginous or meniscal damage. We have produced new guidelines to facilitate the process of creating the posteromedial portal even by inexperienced hands. With a cannulated K-wire and a cannulated rod with sharp teeth, the joint capsule of the posteromedial corner can be penetrated safely with or without viewing the posteromedial corner through the anterolateral portal. Based on our experience of using this guide system, we believe it will be a great help to many orthopaedic surgeons in performing various types of arthroscopic surgery, not only for PCL reconstruction but also for arthroscopic synovectomy.

Arthroscopes↗
PubMed1998

Effects of basic fibroblast growth factor on proliferation and phenotype expression of chondrocytes embedded in collagen gel.

1. Whether basic fibroblast growth factor (bFGF) can stimulate proliferation and synthesis of chondroitin sulfate of chondrocytes in gel culture while maintaining the phenotype was studied. 2. At 3 weeks in culture, the cell number in 1.0 ng/ml (18.5+/-2.1 x 10(5)) and 10.0 ng/ml of the bFGF group (15.3+/-1.9 x 10(5)) was significantly larger than that in 0 ng/ml (12.3+/-2.1 x 10(5)), 0.1 ng/ ml (11.7+/-2.2 x 10(5)) and 100.0 ng/ml of the bFGF group (9.8+/-2.3 x 10(5)). 3. All doses of bFGF used in this study suppressed synthesis of chondroitin 6-sulfate. 4. Chondrocyte phenotype in gel culture was maintained for 4 weeks even with stimulation of bFGF.

Animals↗
PubMed1998

Antimicrobial activity of the diterpenes flexibilide and sinulariolide derived from Sinularia flexibilis Quoy and Gaimard 1833 (Coelenterata: Alcyonacea, Octocorallia).

The soft coral Sinularia flexibilis is rarely overgrown by bacteria and algae. Various studies have shown that it contains diterpenes that protect it from competitors and predators. However, of the many diterpenoids isolated from S. flexibilis, only sinulariolide has been studied for antibiotic properties. Samples of soft corals were collected from Orpheus Island and freeze-dried for chemical extraction and isolation of pure diterpenes. Antimicrobial activity of the diterpenes was determined using the disc assay method with antibiotics as controls and the minimum inhibitory concentrations of the diterpenes were determined using the Tube Dilution Technique. Two out of the five diterpenes tested (sinulariolide and flexibilide), showed marked antimicrobial activity and inhibited growth of Gram-positive bacteria. Flexibilide was effective even at concentrations as low as 5 ppm, whereas sinulariolide was effective at concentrations of 10 ppm. These compounds show potential as antibiotics.

Animals↗
PubMed1997

Mennen plate fixation for fractures of the femoral shaft after ipsilateral hip arthroplasty.

We performed osteosynthesis with the use of a Mennen plate for six patients with femoral fractures in the vicinity of the stem, which occurred after ipsilateral hip arthroplasty. The fixation was so favorable that postoperative deformity was slight. At 4 months after surgery, bone fusion was obtained in all patients, and their hip joint functions recovered to the preinjury level. For femoral fractures in the vicinity of the stem after ipsilateral arthroplasty, there are no suitable fixation methods other than treatment with the Mennen plate. Therefore, this method is recommended.

Adult↗