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Biomedical subjects

F Kanaya

Publications and source records attributed to F Kanaya.

16 recordsLinked to original sources
PubMed2005

Growth kinetics and integrin expression of fibroblasts infiltrating devitalised patellar tendons are different from those of intrinsic fibroblasts.

We compared the biological characteristics of extrinsic fibroblasts infiltrating the patellar tendon with those of normal, intrinsic fibroblasts in the normal tendon in vitro. Infiltrative fibroblasts were isolated from the patellar tendons of rabbits six weeks after an in situ freeze-thaw treatment which killed the intrinsic fibroblasts. These intrinsic cells were also isolated from the patellar tendons of rabbits which had not been so treated. Proliferation and invasive migration into the patellar tendon was significantly slower for infiltrative fibroblasts than for normal tendon fibroblasts. Flow-cytometric analysis indicated that expression of alpha5beta1 integrin at the cell surface was significantly lower in infiltrative fibroblasts than in normal tendon fibroblasts. The findings suggest that cellular proliferation and invasive migration of fibroblasts into the patellar tendon after necrosis are inferior to those of the normal fibroblasts. The inferior intrinsic properties of infiltrative fibroblasts may contribute to a slow remodelling process in the grafted tendon after ligament reconstruction.

Animals↗
PubMed2001

Search for active endogenous retroviruses: identification and characterization of a HERV-E gene that is expressed in the pancreas and thyroid.

To elucidate possible physiological functions of human endogenous retroviruses (HERVs) and their role in the pathogenesis of human diseases, we have developed a strategy to identify transcriptionally active HERV genes. By this approach, we have identified and isolated an active HERV-E gene that was mapped to 17q11. Although the gene was predicted to produce no intact viral particles due to the presence of stop codons, long open reading frames were retained in each gag and pol region. Northern blot analyses revealed in the pancreas (and thyroid) two major transcripts, 3.3 and 4.1 kb in size, associated with 500- to 600-nucleotide-longer minor bands. Preferential expression in pancreas and thyroid gland tissues may suggest a role for this gene in physiological functions common to these tissues.

Base Sequence↗
PubMed2000

Preserved sympathetic skin response at the distal phalanx in patients with carpal tunnel syndrome.

OBJECTIVE: To assess the viability of sympathetic sudomotor fibers in carpal tunnel syndrome (CTS). METHODS: We recorded sympathetic skin response (SSR) with a multichannel recording system. Forty-four patients with CTS (51 hands), 7 patients (7 hands) with asymptomatic median mononeuropathy at the wrist (MMW), and 20 normal subjects (20 hands) were studied. We classified the patients into 4 grades of increasing severity. RESULTS: In the hands of normal subjects, SSR was evoked easily at all recorded sites. SSR at the wrist in patients with asymptomatic MMW decreased in amplitude. SSR was markedly distorted at the wrist in severe grades of CTS. The SSR amplitude ratio (wrist/distal phalanx) decreased significantly with more severe grade (rh=-0.4; P<0.05), but the sensitivity was lower than that of other electrodiagnostic criteria. A patient with persistent allodynia at the wrist after surgery showed the slight recovery of SSR amplitude ratio; the other two patients without allodynia showed substantial recovery of SSR amplitude ratio within 24 weeks after surgery. CONCLUSION: SSR amplitude ratio is a poor indicator of CTS diagnosis, but may be useful in assessing the viability of sympathetic sudomotor fibers and may assist in evaluating the response to surgery.

Adult↗
PubMed1998

Mobilization of a congenital proximal radioulnar synostosis with use of a free vascularized fascio-fat graft.

We present the results of a new mobilization procedure for the treatment of a congenital proximal radioulnar synostosis in seven patients. The operative procedure included separation of the synostosis and placement of a free vascularized fascio-fat graft to prevent recurrent ankylosis. The average age at the time of the operation was eight years and two months (range, six years and four months to eleven years and ten months). All of the patients were boys who had no other congenital anomalies. The radial head was dislocated in all seven patients (anteriorly in two and posteriorly in five). The final four index operations included an osteotomy of the radius in order to reduce the dislocated radial head. The average duration of follow-up was three years and eight months (range, two years and four months to four years and five months). Preoperatively, the patients had had difficulty with holding a bowl of soup and accepting objects, such as coins, into the palm. Postoperatively, they were able to perform these activities. None of the patients had recurrent ankylosis or loss of the flap. The average supination was 26 degrees (range, 10 to 45 degrees), and the average pronation was 45 degrees (range, 10 to 80 degrees). The four patients who had had an osteotomy of the radius in addition to the index procedure did not have a dislocation of the radial head and had an average arc of motion of 83 degrees of pronation and supination. The three patients who had not had an osteotomy had a dislocation of the radial head and an average arc of motion of 40 degrees after the index procedure. These findings demonstrate that separation of a congenital radioulnar synostosis with a vascularized fascio-fat graft and osteotomy of the radius can achieve pronation and supination of the forearm.

Adipose Tissue↗
PubMed1996

Vascularized bone grafts for congenital pseudarthrosis of the tibia.

Eight vascularized fibula grafts and two vascularized rib grafts were used for the treatment of 10 Boyd's Type II congenital pseudarthrosis of the tibia. All but one vascularized fibula graft united within 4 months. The two vascularized rib grafts did not unite until receiving a conventional bone graft. Nine spontaneous fractures were seen in four patients; all were subsequently treated successfully with cast or conventional bone graft. Corrective osteotomies were done in two patients. Follow-up averaged 8 years and 5 months (range, 5 years and 1 month to 14 years and 4 months). Average age at end of follow-up was 13 years and 6 months (range, 7 years and 10 months to 20 years and 4 months). After bony union was achieved, shortening of the affected leg averaged 3.8 centimeters, flexion deformity averaged 20 degrees, and valgus deformity averaged 24 degrees. In three patients, whose leg discrepancy averaged 4.9 centimeters, the leg was lengthened at an average patient age of 13 years and 9 months (age range, 11 years and 7 months to 15 years and 2 months). The resulting limb length discrepancy averaged 2.2 centimeters. Vascularized bone grafting is a reliable technique for achieving bony union in congenital pseudarthrosis of the tibia. Residual shortening may be corrected later by limb lengthening.

Adolescent↗
PubMed1996

Functional degradation of the rabbit sciatic nerve during noncompressive segmental ischemia.

The purpose of this study was to evaluate functional degradation in a nerve with a local ischemic segment created without a direct compression effect. Ischemia of one segment of a rabbit sciatic nerve was induced by stripping the nerve's extrinsic blood supply along 15 cm. Blood flow of both in situ and ischemic nerves was quantitatively measured with radioactive microspheres in six serial segments in seven animals. The flow in one middle segment of the stripped nerve was significantly reduced to 0.1 ml/min per 100 g (p = 0.006). In another eight animals, both in situ and stripped nerves were metabolically challenged with repetitive stimuli (200 Hz). Conduction velocity and peak amplitude were measured before stimuli, after 30 and 60 minutes of stimuli, and after a 30-minute recovery period. Conduction velocity was reduced in both nonischemic and stripped nerves during prolonged repetitive stimulation. Peak amplitude was reduced slightly in the nonischemic group and markedly in the stripped group. Normal or higher values were seen again in both groups during the recovery period. It was demonstrated, therefore, that conduction properties of the nerve, especially amplitude, can be affected by localized ischemia in one segment.

Action Potentials↗
PubMed1996

Sciatic function index, nerve conduction tests, muscle contraction, and axon morphometry as indicators of regeneration.

The purpose of this study was to determine which parameters were the best measure of nerve regeneration, assuming that the sciatic functional index (SFI) represented the "gold standard." Three different sciatic functional indexes and 11 commonly used electrophysiologic and morphologic indicators of regeneration were all determined in 24 rats 12 weeks after one of three lesions was created in the sciatic nerve. With linear regression analysis, only fiber/axon diameter ratio (D/d) and myelin thickness/axon diameter ratio showed statistically significant correlations with sciatic functional index (r = 0.55 and 0.53, respectively). The other 11 parameters had poorer correlation. Therefore, if sciatic functional index is the best measure of comprehensive nerve function, then other parameters are not. It is probable that each parameter measures some different component of the regeneration process. A stepwise multiple linear regression analysis produced a model that included D/d, nerve conduction velocity, and nerve action potential amplitude that gave a slightly better correlation (r = 0.67). The relatively poor correlation between sciatic functional index and the other parameters of nerve function indicates that all nerve regeneration studies must be interpreted carefully before comparisons are made. Furthermore, the best measure of nerve function remains unproved or undiscovered in the experimental animal.

Animals↗
PubMed1995

Free vascularized medial plantar flap with functioning abductor hallucis transfer for reconstruction of thenar defects.

We devised a medial plantar flap with a functioning abductor hallucis for simultaneous reconstruction of thenar skin and muscle defects. The anatomy of the flap was studied in five cadaver dissections before surgical attempts were made in patients, who in this series included three men and one woman (average age 38 years, range 26 to 50 years). All patients were followed a minimum of 3 years (average 3 years and 9 months). In all cases, voluntary abduction of the thumb by the transferred abductor hallucis was achieved and confirmed by electromyography. The functioning medial plantar flap provides not only stable skin to the thenar area with sufficient thenar bulk but also satisfactory abduction of the thumb.

Adult↗
PubMed1993

Blood flow of segmentally divided and folded nerve.

The integrity of the blood supply to three equal segments of a nerve was determined, after the nerve was cut and folded but with its epineurial vasculature remaining intact. A 7.5-cm length of the rabbit sciatic nerve was elevated on a single pedicle. The epineurium was slit longitudinally, and the nerve fascicles were exposed, cut transversely into three equal segments, and then folded so that they were parallel. This is equivalent to a vascularized, folded, nerve graft in the clinical setting. Blood flow was quantified with microspheres in six rabbits, both after elevating the nerve and then again after it had been cut and folded. Mean blood flows in the three segments ranged from 4.4 to 6.2 ml/min/100 g after elevation, and from 4.7 to 8.0 ml/min/100 g after cutting and folding. Dividing and folding of the nerves did not significantly decrease blood flow in any of the nerve segments. The results support this technique as a valid method for vascularized, cable, nerve grafting.

Animals↗
PubMed1992

Functional results of vascularized versus nonvascularized nerve grafting.

Functional results of vascularized nerve grafts (VNG), end-to-end (E-E) repair, and nonvascularized nerve grafts (NNG) were compared using 75 rats. For all three groups, the sciatic function index (SFI) was measured for 12 weeks. For the vascularized nerve graft and nonvascularized nerve graft groups, it was measured every 4 weeks to week 36. The vascularized nerve graft and end-to-end repair groups showed significantly better recovery than the nonvascularized nerve graft group 4 weeks after surgery, and this pattern continued throughout the experiment. Results from the vascularized nerve graft and end-to-end repair groups did not differ significantly. Twelve weeks after surgery, morphologic and electrophysiologic assessments were used to compare the experimental and contralateral legs. The vascularized nerve graft group showed significantly better recovery than the nonvascularized nerve graft group on all measures except muscle weight and axon count, even though the grafts were completed in a normal bed.

Analysis of Variance↗
PubMed1992

Effect of electrostimulation on denervated muscle.

The influence of electrostimulation on denervated and reinnervated muscle was investigated. First, the left peroneal nerve was severed in rats. Wet weight and muscle fiber diameter of denervated anterior tibial muscle was compared as a percentage of contralateral muscle in stimulated and non-stimulated rats. In a second experiment, four weeks after the peroneal nerve was severed, the tibial nerve was cross-sutured to the distal stump of the peroneal nerve. Electrostimulation was continued in rats that had electrostimulation before nerve-crossing. Recovery of wet weight was assessed at eight weeks and at one year after nerve-crossing. The mean decrease in weight and fiber diameter of the denervated muscle was significantly less in the group that was electrostimulated for eight weeks. Recovery of weight of reinnervated muscle was significantly better in the electrostimulated group. Electrostimulation of denervated muscle retarded denervation atrophy and improved recovery after reinnervation.

Animals↗
PubMed1991

Sensory and motor fiber differentiation with Karnovsky staining.

We examined four acetylthiocholine methods based on Karnovsky's procedure--two fast-acting requiring 1 hour and two slow-acting requiring 24 hours. We compared these with our modification, which requires less than an hour and is simple to use. Rabbit sciatic nerves and spinal cords were used to compare methods. Our modification showed clearer differentiation than other fast-acting methods and staining identical to slow-acting methods. In blind examination of radial nerve specimens stained with our method, motor and sensory fascicles were correctly identified, showing sensitivity and specificity of 100%. In 12 clinical cases, our method produced staining in the proximal stump as long as 16 months after injury and in the distal stump as long as 5 days after injury. In 10 of 12 patients, this staining helped in aligning motor fascicles to motor fascicles and sensory fascicles to sensory fascicles.

Acetylthiocholine↗
PubMed1990

Improvement in motor function after brachial plexus surgery.

Motor functional recovery of 52 patients with brachial plexus surgery followed up for more than 2 years was evaluated. Fifty-eight surgical procedures were done, including autologous nerve grafting (38 cases), neurolysis (14 cases), and neurotization (6 cases). Overall results, evaluated according to the 0 to 5 formula of the Medical Research Council, were as follows: good, 58%; fair, 15%; and poor, 27%. Good results were evident in 58% of patients with nerve grafts and in 64% of those with neurolysis. In patients with neurotization, no good recovery and only one fair recovery were seen. Patients with open injuries showed good recovery, whereas the group with closed injury showed good recovery in only 48%. Patients with closed injuries caused by traffic accidents showed a worse recovery than those caused by other means. Patients with closed injuries and nerve grafting done within 3 months of injury or neurolysis within 6 months showed better recovery.

Adolescent↗
PubMed1988

[An experimental study on denervated muscle atrophy--effect of electrostimulation and comparison with immobilization muscle atrophy].

The efficacy of causing muscle atrophy was compared among denervation, arthrodesis and tenotomy in rat anterior tibial muscle. Reduction of wet weight was most pronounced in denervated muscle and least in arthrodesed muscle. Histochemical investigation by ATPase stain revealed that atrophy of Type 1 and Type 2 fiber was more severe in denervated muscle group than in the other two groups. Type 2 fiber atrophy was dominant in denervated muscle and in arthrodesed muscle. Type 1 fiber atrophy was dominant in tenotomized muscle. The effect of electrostimulation on denervated muscle was investigated. Electrostimulation significantly reduced the degree of denervation atrophy. Four weeks after severance of peroneal nerve, tibial nerve-crossing was done and electrostimulation was continued for eight weeks. Recovery of wet weight of re-innervated muscle with electrostimulation was significantly better than that without electrostimulation. Electrostimulation applied to denervated muscle reduced the progress of atrophy and improved the recovery after nerve repair.

Animals↗