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Biomedical subjects

S Soeda

Publications and source records attributed to S Soeda.

At least 19 recordsLinked to original sources

Binding and transport of gangliosides by prosaposin.

Prosaposin, the precursor of saposins A, B, C, and D, which activate lysosomal hydrolysis of sphingolipids, exists in various tissues and body fluids and is especially abundant in the nervous system. Prosaposin and saposins A,B, C, and D formed stable complexes with 13 different gangliosides as measured by an assay using column chromatography. Gangliosides of the gangliotetraose type (a series) were bound with high affinity, whereas b series gangliosides, O-acetylated gangliosides, and gangliosides with shorter carbohydrate chains, were bound with lower affinity. Prosaposin and saposins transferred gangliosides from donor liposomes to erythrocyte ghost membranes. Prosaposin also stimulated ganglioside GM1 beta-galactosidase more than mature saposins. Prosaposin exists as a secretory protein and as an integral membrane protein, and we propose that prosaposin is active as a ganglioside binding and transport protein in vivo.

Biological Transport

Fibrinolytic and anticoagulant activities of highly sulfated fucoidan.

A series of fucoidan [sulfated poly(L-fucopyranose)] derivatives were prepared by chemical sulfation and desulfation, and they were tested for their abilities to stimulate tissue plasminogen activator (t-PA)-catalyzed plasminogen activation, clot lysis, and the inhibition of fibrin polymer formation. The magnitude of their activities was dependent upon the degree of sulfation. A striking feature of the sulfated fucoidan was that, unlike heparin, it stimulated t-PA-induced plasma clot lysis by protecting plasmin activity from alpha 2-plasmin inhibitor and decreased the rate of fibrin polymer formation. The inhibition of hyaluronic acid-mediated enhancement of fibrin clot formation was also observed with the fucoidan derivative. We also showed that highly sulfated fucoidan prevents significantly endotoxin-induced hepatic vein thrombosis in the hyperlipemic rat model. The present results are the first to describe the fibrinolytic and anticoagulant activities of fucoidan, and thus may provide useful clues for the development of an ideal thrombolytic agent.

Animals

Free thin osteo-onychocutaneous flaps from the big toe for reconstruction of the distal phalanx of the fingers.

Free osteo-onychocutaneous flaps from the big toe have frequently been used for the reconstruction of distal phalangeal loss of the fingers. The thickness of the fatty tissue, however, makes these flaps bulky. We believe this disadvantage can be overcome with a free thin osteo-onychocutaneous flap from the big toe and consider this thin composite flap to be a superior method of reconstruction for the treatment of distal phalangeal loss.

Adolescent

Free thin paraumbilical perforator-based flaps.

A free paraumbilical perforator-based flap fed by a muscle perforator from the inferior deep epigastric artery and with no muscle was used in 13 patients. Among them, a free thin paraumbilical perforator-based flap with a thin layer of fat, to protect the subdermal plexus of the vessels, was used in seven patients. The dominant pedicle perforator of this thin flap is usually located around the umbilicus and a large flap can be obtained. Its critical length-to-breath ratio is considered to be 4:3. The advantages of this flap are a long and large vascular pedicle, rare postoperative abdominal herniation, little bulkiness of the flap, and a relatively large skin territory. The disadvantages are technical difficulties in dissection of the perforator and anatomical variation in the location of the perforator. We believe this flap largely overcomes the problems of the conventional rectus abdominis musculocutaneous flap.

Abdominal Muscles

Extended latissimus dorsi musculocutaneous flaps for extremely wide cervical skin defects involving the cervical esophagus.

Two cases using island distally and anteriorly extended latissimus dorsi musculocutaneous flaps for one-stage reconstruction of pharyngoesophageal defects of the entire front of the neck are reported. The advantage of this flap is its extremely large skin territory, which provides a reliable vascular supply. This flap is suitable for extremely wide cervical defects where the recipient vessels are damaged after severe infection and irradiation.

Aged

The use of arteriovenous anastomosis for replantation of the distal phalanx of the fingers.

Microvascular replantation at the distal phalangeal level has recently been reported by several authors, but as yet the rate of success has not been constant owing to the technical difficulties associated with small vessels. To solve this problem, over the last 4 years we have used arteriovenous anastomosis to reestablish either the arterial system or the venous drainage system in the 33 digits of our 23 patients. The results have been excellent, with a 91 percent success rate. Such results for replantation of the distal phalanx may be maintained and improved if a small venous graft with several branches is also utilized.

Adolescent

An enzyme-linked immunosorbent assay for the detection of plasminogen activator-induced fribrin clot lysis in a circulating plasma system.

A technically easy and sensitive method for the evaluation of the fibrinolytic potency of plasminogen activator in a circulating plasma system was developed. A circulating apparatus was prepared by connecting silicone tubes with two separate chambers. Human plasma and plasminogen activator were allowed to circulate from one chamber through a peristaltic pump into another one which contained biotin-labeled fibrin clot. The extent of fibrinolysis was evaluated on streptavidin-coated microtiter plates by measuring the amount of the avidin-bound fibrin degradation products with peroxidase-linked antibody. The detection limit of the fibrinolytic products was 1.5 ng/ml. The present method dose not require any specialized equipment and is also applicable to a low-cost routine measurement of the thrombus selectivity of plasminogen activator.

Bacterial Proteins

Electron microscopic observations of degeneration of human Pacinian corpuscles in amputated fingers.

Amputated human fingers were used to observe the morphologic changes in degeneration of Pacinian corpuscles, and postoperative moving two-point discrimination of the replanted fingers was examined to analyze sensory recovery after replantation. Normal corpuscles are composed of an axon terminal and inner and outer cores, resembling a sliced onion. The inner core is composed of thin, multilayered lamellar cells, and the outer core consists of multiple layers of thin perineurial cells. Based on our morphologic findings, following mitochondrial degeneration in the axon terminal, the terminal and inner core cells disappeared within 9 to 16 hours, but the outer core did not lose its structure until more than 24 hours after amputation. Collagen fibrils in the corpuscles appeared from 5 hours after amputation and periodically increased their amount up to 27 hours after amputation. Postoperative sensory recovery of the replanted fingers was significantly poorer with 9 hours or more of cold ischemia. These findings suggest that the inner core cells originating from Schwann cells degenerate at over 9 hours after amputation, and this may be related to the poor sensory recovery of replanted fingers. It also appears that the outer core cells originating from the perineurial cells in the amputated fingers survive even up to 27 hours after amputation and produce collagen fibrils in the extramatrix spaces of the outer core cells.

Adult

An arterialised venous flap using the long saphenous vein.

Free arterialised venous flaps and an arterialised osteocutaneous venous flap, fed by an arterialised long saphenous vein, were used successfully in three cases. This flap has a larger skin territory than those previously reported and the incorporation of bone into such a flap has not been reported before.

Aged

Free vascularized deep peroneal neurocutaneous flap for repair of digital nerve defect involving severe finger damage.

A free vascularized deep peroneal nerve graft seems to be the most suitable method for repairing digital nerve defects involving severe finger damage. We report a patient in which this graft was used as a neurocutaneous flap. The advantages of this method are its excellent vascularity, minimal functional disturbance to the donor foot, and the possibility of versatile application.

Finger Injuries

One-stage reconstruction for amputated thumbs with melanoma.

The reconstruction of amputated thumbs is difficult because of a poor prognosis, and the varying length and volume of the lost thumbs. Two patients underwent reconstruction of amputated thumbs in one stage with the use of a modified wrap-around flap procedure. An onychocutaneous flap from the big toe is suitable for partial defects, including the nail of the distal phalanx. A combined dorsalis pedis flap and wrap-around flap is also superior for total thumb reconstruction after amputation at the metacarpal phalanx involving the thenar region.

Amputation, Surgical

Free posterior tibial perforator-based flaps.

Free posterior tibial perforator-based flaps, fed by a perforator from the posterior tibial artery, were applied in 2 patients. The advantages of this flap are that they are reliable, relatively large and thin flaps, making it possible to use an innervated flap without sacrificing the posterior tibial artery. This flap provides great advantages for the reconstruction of skin defects at the extremities.

Adult

A new dressing method for free skin grafting in hands.

Using adhesive drapes and a disposable suction drain, the grafted area is compressed by positive pressure that is equivalent to the negative pressure of a suction drain. With this dressing method, the graft can be observed throughout the postoperative course, and can be applied with uniform and constant pressure. Thin drapes accommodate well to various shapes, so this method is uniquely qualified in free skin grafting of hands.

Adult

High-voltage electrical injury: electron microscopic findings of injured vessel, nerve, and muscle.

Bilateral legs damaged by high-voltage electrical injury were treated by amputation and a free thin rectus abdominis myocutaneous flap with reduced muscle. Damaged arteries at 2 months after injury showed disappearance of endothelium, and a decreased number and morphological changes in smooth-muscle cells. Injured nerves and muscles showed early regenerating processes after total degeneration, and no progressive muscular necrosis. These results suggest that severe degeneration of the neurovascular bundle and muscle is unavoidable in high-voltage electrical injuries of the extremities. Therefore, early amputation, sequential debridement, late coverage by a flap, and prolonged rehabilitation are required in this injury.

Amputation, Surgical

Combined vascularized fibula and peroneal composite-flap transfer for severe heat-press injury of the forearm.

A free combined vascularized fibula and peroneal composite flap was transferred to the forearm in a patient with a severely damaged forearm following a heat-press injury. The operative technique, postoperative management, and subsequent clinical course are described, and the advantages of this method are outlined. Not only can the fibula now be used as a free vascularized bone graft in simple bone defects, but further applications, such as a combined fibula and peroneal composite flap, can be employed in the treatment of severely damaged forearms.

Burns

A combined rectus abdominis musculocutaneous flap and vascularized iliac bone graft with double vascular pedicles.

Although a free vascularized iliac bone graft has been successfully used for the reconstruction of large bone defects, there is a serious problem of how to repair in one stage patients having a large bone defect with a very wide skin defect. A free combined rectus abdominis musculocutaneous flap and vascularized iliac bone graft with double vascular pedicles seems to be one of the most suitable methods for patients having large defects of both bone and skin. Based on our patient, the main advantage of this flap is the extreme width of the skin territory. The pedicle vessels are large and long, and the donor scar can be made in an unexposed area. This flap should be considered for use in one-stage reconstructions of large defects of both bone and skin in the leg region.

Humans

Free, thinned, paraumbilical perforator-based flaps.

Free, thinned paraumbilical perforator-based flaps, fed by a muscle perforator from the inferior, deep epigastric artery and having no muscle and little fatty tissue components, were used in two cases. This flap provides great advantages in overcoming some of the problems of the conventional rectus abdominis musculocutaneous flap.

Abdominal Muscles