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Biomedical subjects

J Nagano

Publications and source records attributed to J Nagano.

At least 19 recordsLinked to original sources
PubMed1990

Replacing the medial collateral ligament with an allogenic tendon graft. An experimental canine study.

In order to determine whether an allogeneic tendon could be used to replace an extra-articular ligament, the right medial collateral ligament from 11 adult dogs was replaced with a fresh-frozen allogeneic patellar tendon. At each of 3, 6, 15, 30 and 52 weeks postoperatively, one dog was killed for micro-angiographical and histological studies; at 52 weeks the remaining six dogs were killed for tensile testing. Micro-angiograms showed that the allogeneic tendon was revascularised with infiltration of the mesenchymal cells from the surrounding tissues and both ends of the graft. Histologically, the alignment of the fibroblasts and collagen bundles became more regular over time, without any immunological rejection. A biomechanical study performed at 52 weeks found no significant difference in stiffness or ultimate load between normal and reconstructed ligaments. Fresh-frozen allogeneic tendons are therefore considered useful for extra-articular ligament reconstruction.

Angiography↗
PubMed1989

Arthropathy of the wrist in leprosy--what changes are caused by long-standing peripheral nerve palsy?

A radiographical screening study of 338 leprotic patients was performed. Clinically, according to a nerve score (NS) designed by us, 12.9% of 674 hands showed mild nerve palsy (NS 5 or 6), 75.9% moderate (NS 3 or 4), and 11.4% severe (NS less than 2). Twenty-nine hands of 26 patients (NS 4.2 on average) demonstrated abnormal changes of the wrist joint on radiographs. We classified them into four groups: (a) lunate collapse (four patients), (b) scaphoid nonunion (eight), (c) scaphoid cyst (three), and (d) trapezium OA (11). In the lunate collapse and the scaphoid nonunion groups, destructive and reconstructive changes as described by Eichenholtz were identified on plain film. These groups demonstrated remarkable instability of the stress and dynamic roentgenograms. In contrast, the scaphoid cyst and trapezium OA wrists showed neither fracture nor instability and fewer changes than the other two groups. We considered the destructive changes that had taken place in the lunate collapse and the scaphoid nonunion wrists to be neuroarthropathy due to long-standing nerve palsy.

Adult↗
PubMed1988

Neuroarthropathy of the foot in leprosy.

Among 449 patients with leprosy, 40 had clinical and radiographic evidence of neuroarthropathy in 50 feet. These changes were classified into four types according to the joints first involved by major lesions: ankle (25 feet), midtarsal (15 feet), tarsometatarsal (7 feet) and subtalar (3 feet). The progression of joint destruction was different in each type, but despite the severe destructive changes seen in radiographs, the patients had relatively few complaints. The muscles innervated by the peroneal nerve were severely paralysed in ankle and midtarsal types and it seems that, over a long term, repeated trauma and/or abnormal stress may lead to these types of neuroarthropathy. Neuropathy was less severe in the tarsometatarsal type of joint degeneration; the pathogenesis in this type seemed to be mainly direct trauma to the forefoot.

Adult↗
PubMed1988

Maturation of allograft tendons transplanted into the knee. An arthroscopic and histological study.

We have performed an arthroscopic and histological study of the remodelling process of allogeneic tendons transplanted into the human knee as anterior cruciate ligament substitutes. Arthroscopic observations from six weeks to 55 months after operation showed that the grafts were viable, and that early surface hypervascularity subsided with time; moreover, these appearances remained unchanged from 11 months postoperatively onwards. Histological studies from three to 55 months after operation showed that all the grafts were infiltrated with fibroblasts, and that cellularity in their substance reduced with time, remaining unchanged from 18 months onwards; the collagen bundles were aligned as in a normal ligament from six months onwards. These findings suggest that the grafts reach maturity within the first 18 months and remain unchanged as viable ligaments thereafter.

Adolescent↗
PubMed1986

Critical analysis of results of treatment of 201 tibial shaft fractures.

Two hundred one tibial shaft fractures, 160 closed and 41 open (Grades I and II), were treated between January 1978 and June 1982. Sixty patients underwent closed intramedullary Arbeitsgemeinschart Osteosynthesisfragen/Association for the Study of Problems of Internal Fixation (AO/ASIF) nailing with reaming and 141 patients were treated with closed reduction and cast immobilization. Intramedullary nailing resulted in one (1.7%) nonunion, two (3.3%) infections, and no malunions. In the cast treatment group there were 14 (9.9%) delayed or nonunions, two (1.4%) infections, and six (4.3%) malunions. Within this group there were 19 early failures from either inadequate reduction or loss of reduction, which led to a change from nonoperative to operative methods of management. The interval between injury and return to work was 22 weeks in the nailed group, compared with 25.8 weeks in the cast immobilization group.

Adolescent↗