Biomedical subjects

S Soeda

Publications and source records attributed to S Soeda.

At least 55 records · Page 3Linked to original sources

PubMed1995

Hereditary multiple glomus tumors involving the glans penis. A case report and review of the literature.

BACKGROUND: Multiple glomus tumors are extremely rare and seldom demonstrate malignant change. OBJECTIVE: To describe an exceptionally rare case of familial multiple glomus tumors involving the glans penis. METHODS: Multiple glomus tumors in a father and son were studied by light and electron microscopy. RESULTS: The clinical presentation of the two patients was similar, and atypical glomus cells were identified in both son and father. The histology of the tumor cells suggested that they were malignant, yet the clinical course has been benign. CONCLUSION: Despite their malignant histologic appearance, the behavior of familial glomus tumors is benign. A conservative approach to treatment appears warranted. The diagnosis and management of these lesions should be based on clinical behavior rather than histopathology.

Adult↗

PubMed1995

Fatty acyl-Co A: sphingosine acyltransferase in bovine brain mitochondria: its solubilization and reconstitution onto the membrane lipid liposomes.

Fatty acyl-Co A: sphingosine acyltransferase (ceramide synthase, EC 2.3.1.24) is mainly localized in the microsomal and mitochondrial membranes. Attempts to isolate the enzyme have failed, largely because there has been little or no detection of the enzyme activity in detergent extracts. In this study, we solubilized the membrane-bound enzyme from bovine brain mitochondria with a Tris-HCl buffer containing 2% Triton X-100 and, after removal of the detergent, reconstituted it with the membrane lipid liposomes. The specific activity of the reconstituted enzyme was approx. 8 times higher than that of the solubilized enzyme. We next examined the lipid dependence of the enzyme, using various phospholipid liposomes. The ability of phospholipids to enhance the activity of solubilized ceramide synthase was specific and structure-related. The most potent stimulator was phosphatidylserine liposomes, suggesting an important role of the net negative charges. This paper also describes a highly reproducible high-performance liquid chromatographic (HPLC) procedure for the determination of ceramide synthase activity. Combination of the HPLC method with the reconstituted enzyme system appears to be suitable for elucidating the characteristics of this enzyme.

Acyltransferases↗

PubMed1994

Aminated fucoidan promotes the invasion of 3 LL cells through reconstituted basement membrane: its possible mechanism of action.

Fucoidan is reported to have an antimetastatic activity. In the present study, we prepared an amino group-introduced derivative of fucoidan and examined its effect on the invasion of 3 LL cells through a reconstituted basement membrane (MatrigelTM). Unlike native fucoidan, the aminated derivative promoted the tumor cell invasion: maximal promotion (240% of control invasion) was obtained with 5 micrograms/ml. However, with higher concentrations (10-30 micrograms/ml) of the fucoidan derivative, the promotion was gradually reduced to 130% of control. Both native and aminated fucoidans inhibited specifically the attachment of 3 LL cells to laminin. Interestingly, aminated fucoidan, unlike the native one, promoted the tumor cell adhesion to immobilized synthetic laminin B 1 chain peptide, YIGSR, over a concentration range of 0.5-5 micrograms/ml. Higher concentrations (7-20 micrograms/ml) of the aminated derivative suppressed the adhesive ability of 3 LL cells to YIGSR. 3 LL cells secreted a 50-kDa form of urokinase-type plasminogen activator (u-PA) in the culture medium. Addition of aminated fucoidan (5 micrograms/ml) or YIGSR (10 micrograms/ml) resulted in a 1.7-fold increase in u-PA activity. This effect was enhanced up to 3.5-fold when both substances were simultaneously added. The addition of native fucoidan had no effect. The present results suggest that the 67-kDa receptor-mediated binding of 3 LL cells to laminin activates their invasiveness, especially by enhancing the extracellular u-PA levels. Aminated, but not native, fucoidan may act to enhance the laminin-receptor interaction at the limited concentration range.

Amination↗

PubMed1994

Regulation of prolyl oligopeptidase activity in regenerating rat liver.

We have previously shown that the naturally occurring polyamines, spermidine and spermine, reverse effectively the in vitro inhibition of prolyl oligopeptidase (POPase) by its endogenous inhibitor by forming a kinetically significant complex (Soeda et al., J. Neurochem. (1986) 46, 1304-1307). In this study, we examined changes in the activities of POPase and its endogenous inhibitor and in the concentrations of polyamines during the regeneration of rat liver. POPase activity in the liver cytosol peaked 2 days after partial hepatectomy and then decreased near to control activity by 9 days, without its altered synthetic levels. Total polyamine concentrations also peaked at 2 days and remained elevated by 9 days, while cytosolic POPase inhibitor activity was minimal (56% of control) at 2 days. Treatment of the animals with a synthetic POPase inhibitor, Z-Gly-Pro-CHN2 (4 mg/kg), resulted in an obvious suppression of the liver regeneration. These results imply that the activity of POPase involved in nonlysosomal proteolytic pathway is exquisitely regulated by changes not only in its endogenous inhibitor levels but also in intracellular cationic potentials such as polyamines, and that POPase plays a crucial role for the growth and differentiation of liver cell.

Amino Acid Sequence↗

PubMed1994

Facial contour reconstruction in lipodystrophy using a double paddle dermis-fat radial forearm free flap.

Facial lipodystrophy is a relatively rare disease and very little has been reported concerning the reconstruction of this facial deformity compared with Romberg's disease. In this article we report a new surgical procedure using a double paddle radial forearm dermis--fat free flap. By using this unique flap, we could reconstruct soft tissue defects on both cheeks in a one-stage operation using one flap. In the previous conventional procedure, two flaps are required for the reconstruction of bilateral defects on the face. Therefore, we also made a comparison between our flap and the conventional flap with regard to their advantages and disadvantages. Although this is a limited experience, we think using this flap is a preferable method of treating facial lipodystrophy.

Adult↗

PubMed1994

Free vascularized iliac osteomusculocutaneous flaps based on the lateral circumflex femoral system for repair of large mandibular defects.

A free vascularized iliac osteocutaneous flap based on the ascending and transverse branches of the lateral circumflex femoral system was studied by cadaveric investigation. These composite flaps were successfully used in 2 patients with both large mandibular and soft-tissue defects. The advantages of this flap are that (1) the distal portion of the flap is relatively thin, (2) the pedicle vessels are long and large, (3) the skin territory is extremely wide, (4) repositioning of the patient during the operation is unnecessary, (5) the flap can be elevated while the recipient mandibular region is resected by two teams because the donor site is far from the head and neck regions, (6) the donor scar is in an unexposed area and its location permits easy concealment, and (7) subtotal loss of the mandible can be reconstructed with the use of split crests from either side of the ilium because the external and the internal cortices are fed independently by the lateral circumflex femoral and the deep circumflex iliac systems. This appears to be a new concept for reconstruction of total mandibular loss.

Aged↗

PubMed1994

Free rectus femoris muscle transfer for one-stage reconstruction of established facial paralysis.

The free vascularized rectus femoris muscle graft with a long motor nerve was used for reconstruction of unilateral established facial paralysis in one stage. The pedicle vessels were anastomosed to the recipient vessels in the ipsilateral face, and the motor nerve of the muscle, which was led through the upper lip, was sutured to the contralateral facial nerve. The advantages of this one-stage reconstruction as compared with surgery involving second-stage reconstruction are that the reconstruction can be completed in one stage and that the period required for muscle refunctioning after surgery is short. The vascular supply of the rectus femoris muscle can emanate mainly from the lateral circumflex femoral artery. In our cadaveric study, five types of variation were found for origination of a nutrient artery of the muscle. The most common type was one in which the artery derived from the descending branch of the lateral circumflex femoral artery (39 percent). The motor nerve of the rectus femoris muscle is derived from the femoral nerve under the inguinal ligament and runs downward through the intermuscular space between the sartorius muscle and the iliopsoas muscle before entering the posteromedial part of the upper third of the rectus muscle. The advantages of using the rectus muscle are as follows: (1) safety and simplicity exist with one main large arterial supply for arterial anastomosis; (2) the length of the femoral nerve (more than 20 cm) is adequate for reaching the contralateral facial nerve for suturing; (3) a simultaneous operation by two teams is possible with the patient in the supine position; (4) the force and distance of contraction are appropriate to reanimate the face; (5) the rectus muscle can be separated as a segment with appropriate lengths, size, and power for replacing lost muscles in the face; (6) the tendinous fascia in both ends provides a reliable point for anchoring sutures, which provides firmer attachment; and (7) no loss of donor leg function occurs.

Adolescent↗

PubMed1994

Inhibitory effect of oversulfated fucoidan on invasion through reconstituted basement membrane by murine Lewis lung carcinoma.

We investigated the effects of native, oversulfated, and desulfated fucoidans and heparin on the invasion of 3 LL cells through Matrigel. Of the four polysaccharides tested, oversulfated fucoidan was the most potent inhibitor of tumor cell invasion and inhibited most potently and specifically the tumor cell adhesion to laminin. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the binding of elastase-cleaved laminin to fucoidan- and heparin-Sepharoses showed that both polysaccharides bound to the 62 and 56 kDa fragments. Pretreatment of 3LL cells with native or oversulfated fucoidan reduced their adhesive potency to laminin. The two fucoidans inhibited further the laminin binding of 3 LL cells which had been pretreated with a laminin-based pentapeptide, YIGSR. These results suggest that fucoidan specifically binds to not only the heparin binding domain(s) of laminin but also site(s) other than the cell surface laminin receptor. 3 LL cells secreted a 50 kDa form of urokinase-type plasminogen activator (u-PA). The extracellular level of u-PA activity was increased 1.7 times by addition of laminin but not type IV collagen. Oversulfated fucoidan most potently reduced the increased u-PA levels. Therefore, the reduction in in vitro invasiveness of 3 LL cells in response to either fucoidan or its oversulfated derivative may result from an inhibition of physical interaction between the tumor cells and the Matrigel (laminin), followed by a suppression of the laminin-induced increase in extracellular u-PA.

3T3 Cells↗

PubMed1994

Preparation of aminated fucoidan and its evaluation as an antithrombotic and antilipemic agent.

Fucoidan, a sulfated poly(L-fucopyranose), is an effective anticoagulant in vitro and in vivo. In the present study, an aminated derivative of fucoidan was prepared and examined for its fibrinolytic and anticoagulant activities. The aminated derivative was more potent than native fucoidan as a stimulator of tissue plasminogen activator-induced plasma clot lysis, and its effectiveness was comparable to that of oversulfated fucoidan reported previously. Furthermore, the ability of aminated fucoidan to accelerate heparin cofactor II-mediated thrombin inhibition was 2.3 times more potent than that of native fucoidan. Aminated fucoidan effectively prevented endotoxin-induced hepatic vein thrombosis in hyperlipemic rats and decreased the elevated levels of serum cholesterol and triglyceride. The present results that the anticoagulant and antilipemic potency of fucoidan can be improved by charge modification may provide useful clues for the development of an ideal anticoagulant and antilipemic drug.

Amines↗

PubMed1993

Preparation of oversulfated fucoidan fragments and evaluation of their antithrombotic activities.

Oversulfated fucoidan fragments (20-40 and 40-60 kDa) were prepared, and their fibrinolytic and anticoagulant activities were compared with those of oversulfated fucoidan (100-130 kDa) reported previously [Soeda et al., Biochem. Pharmacol. 43, 1853-1858, 1992]. The results of these experiments indicated that the in vitro abilities of oversulfated fucoidan to stimulate tissue plasminogen activator (t-PA)-catalyzed plasminogen activation and to potentiate thrombin inhibition by antithrombin III or heparin cofactor II decreased with a decrease in its molecular size. However, the preventive effects of both fucoidan fragments on endotoxin-induced hepatic vein thrombosis in hyperlipemic rats were almost the same as that of oversulfated fucoidan (100-130 kDa). We also found that, unlike heparin treatment, the concentrations of serum and vascular endothelium t-PA in rats treated with oversulfated fucoidan or its fragments (1 mg each/kg/week) were maintained at normal levels. The 20-40 and 40-60 kDa fragments had an ability to decrease the elevated levels of serum cholesterol in hyperlipemic rats, whereas the 100-130 kDa fucoidan derivative did not. These results suggest that oversulfated fucoidan and its fragments have another function(s), besides the regulation of blood coagulation and fibrinolysis, and are of therapeutic benefit for the prevention of thrombus formation in hyperlipemia.

Animals↗

PubMed1993

Binding of cerebrosides and sulfatides to saposins A-D.

Saposins are a family of four small glycoproteins, all of which are derived from prosaposin, and are involved in the lysosomal hydrolysis of various sphingolipids. Results from this investigation demonstrate that saposins A-D bind to galactosyl- and glucosylceramide. The binding was highly dependent on the solution pH; maximum binding of glucosylceramide to all saposins occurred at pH 7. Maximum binding of galactosylceramide to saposins B and D occurred at a more basic pH (8.5). The binding of glucosylceramide to saposins was significantly inhibited by Mg2+, Ca2+, or Zn2+. Although maximum binding of sulfatide to saposins A, C, and D occurred at acidic pH, the binding to saposin B was maximum at pH 8.5. Saposin A also bound sphingomyelin or phosphatidylcholine at neutral pH. No significant binding was evident between these lipids and saposins B-D at any pH value. The existence of saposin-lipid complexes was further confirmed in selected samples by gel filtration, isoelectric focusing, and a TLC binding assay. We have also shown that galactosylceramide bound to saposins A-D was efficiently transported to a rat brain microsomal fraction. This result suggests that saposins and possibly their precursor, prosaposin, may be involved in membrane biogenesis such as the assembly of myelin and plasma membranes.

Animals↗

PubMed1993

Effect of saposins on acid sphingomyelinase.

The effect of saposins (A, B, C and D) on acid sphingomyelinase activity was determined using a crude human kidney sphingomyelinase preparation and a purified sphingomyelinase preparation from human placenta. Saposin D stimulated the activity of the crude enzyme by increasing its apparent Km and Vmax. values for sphingomyelin hydrolysis. Unlike the crude enzyme, the activity of the purified enzyme was strongly inhibited by saposin D as well as other saposins. Saposin D decreased the apparent Km and Vmax values of purified sphingomyelinase activity. The effects of saposin D on the activity of different sphingomyelinase preparations appear to depend on Triton X-100, which is present in the crude enzyme but not in the purified enzyme. When the detergent was removed from the crude preparation, the effect of saposin D changed from being stimulatory to inhibitory. Conversely, when the detergent is added to the purified enzyme, the effect of saposin D on sphingomyelinase activity changed from being inhibitory to stimulatory. While other saposins were inhibitory or had no effect on sphingomyelinase activity in the above assay system, not only saposin D but also saposins A and C exhibited a stimulatory effect upon purified sphingomyelinase activity when the substrate, sphingomyelin, was added in the form of liposomes without detergent. Saposin B was not only inhibitory in the liposome system, but also reduced the stimulatory effect of saposins A, C and D. These observations indicate that the stimulatory effect of saposins A, C and D on acid sphingomyelinase activity is greatly influenced by the physical environment of the enzyme and suggest that similar effects by saposins may be exerted in lysosomal membranes.

Detergents↗

PubMed1993

The effect of carbohydrate removal on stability and activity of saposin B.

Saposin B is involved in the hydrolysis of sulfatides, GM1 ganglioside, globotriaosylceramide, and several other sphingolipids and glycerolipids by lysosomal hydrolases. Saposin B is one of four small glycoproteins (saposins) derived from prosaposin. The carbohydrate chain of saposin B was removed and deglycosylated saposin B was characterized and compared with native saposin B. Deglycosylated saposin B stimulated the enzymatic hydrolysis of ganglioside GM1 by acid beta-galactosidase and sulfatide by arylsulfatase A to the same extent as native saposin B. In addition deglycosylated saposin B bound sulfatide and GM1 ganglioside identical to native saposin B. The stability of native saposin B to proteolytic digestion was unchanged by deglycosylation. Neither native saposin B nor deglycosylated saposin B were hydrolyzed by trypsin, endoproteinase Glu-C (V-8), chymotrypsin, or a mixture of acid proteases isolated from human testis. Unlike its effect on metabolic stability, the carbohydrate chain appears to affect folding of saposin B. When native and deglycosylated saposin B were reduced under denaturing conditions and refolded under identical conditions examination of the refolded products indicated that each protein was refolded in a qualitatively different way. A human mutation in saposin B-deficient metachromatic leukodystrophy, in which its glycosylation site is eliminated, has been reported. Our observations suggest that instability of the mutated saposin B is not due to the absence of a protective effect of the carbohydrate chain on proteolysis, but is likely due to aberrant folding resulting from the absence of a carbohydrate chain.

Carbohydrates↗

PubMed1993

The gluteal perforator-based flap for repair of sacral pressure sores.

A gluteal perforator-based flap employing the gluteus maximus muscle perforators located around the sacrum is described. A cadaveric study disclosed the existence of several significant perforators all around the gluteal region. Among these, the parasacral perforators originating from the internal pudendal artery and lateral sacral artery have proven useful for the repair of sacral pressure sores. A total of eight decubitus in seven patients were treated with gluteal perforator-based flaps. There were no postoperative complications, such as flap necrosis and wound infection, with the exception of fistula formation in one case. This flap requires no transection or sacrifice of the gluteus maximus muscle, and elevation time for the flap is short. However, the perforators are located at various sites and thus require some careful dissection.

Adult↗

PubMed1993

Extended wrap-around flap for reconstruction of the finger with recurrent arteriovenous malformation.

Treatment of arteriovenous malformations of the finger is difficult because complete resection of malformations by ligation or en bloc resecting methods is impossible. We used an extended wrap-around flap consisting of a combined wrap-around flap and a dorsalis pedis flap to reconstruct the soft-tissue defects following complete resection of a recurrent malformation in the index finger. This method has two advantages: no postoperative recurrence of the malformation is expected, and the affected finger can be preserved. However, it is indicated only for malformations with no invasion to the bone and localized in one finger.

Adult↗

PubMed1993

Sixty cases of partial or total toe transfer for repair of finger losses.

Our experience with partial or total toe transfers for the reconstruction of finger deficits is presented. Sixty-one toes were transferred to reconstruct finger deficits in 60 patients. The transfers from the big toe consisted of 3 vascularized whole-nail grafts, 4 onychocutaneous flaps which included the nail and a skin flap from the toetip, 16 thin osteo-onychocutaneous flaps, 4 wrap-around flaps, and 3 combined wrap-around and dorsalis pedis flaps. The transfers from the second toe consisted of 6 trimmed toetips including the nail, 16 second toes, 1 combined second toe and a dorsalis pedis flap, and 1 second toe and third toe. The other transfers mainly consisted of other flaps, including a hemipulp flap and a first web space flap. Regarding the transfers from the big toe, vascularized nail grafts and onychocutaneous flaps were found to be most suitable for the treatment of total nail loss, thin osteo-onychocutaneous flaps for distal phalangeal loss of the thumb, wrap-around flaps with a vascularized iliac bone graft for thumb loss above the metacarpal joint, and the combined wrap-around and dorsalis pedis flaps for a total thumb deficit. Regarding the transfers from the second toe, the trimmed toetips including the nail were most suitable for claw nail deformities, the second toe was most suitable for finger loss except for the thumb with the proximal interphalangeal joint, and the combined second toe and dorsalis pedis flap was most applicable for a total thumb deficit including thenar skin loss.

Adult↗

PubMed1993

Free anterolateral thigh flaps for reconstruction of head and neck defects.

The anterolateral thigh flap is a septocutaneous artery flap based on the septocutaneous or muscle perforators of the lateral circumflex femoral system. Little has been reported about the variations in its vascular anatomy and its application for head and neck reconstruction. We report 22 cases in which this flap was used for the reconstruction of head and neck defects. Based on our clinical and cadevaric experiences, the derivation of the vascular pedicle of this flap has four variations by which the septocutaneous perforators are derived from the descending branch of the lateral circumflex femoral system and/or from the transverse branch of that system, or for which there are no septocutaneous perforators but there are muscle perforators originating from the lateral circumflex femoral system. Clinically, the vascular variations and the locations of perforators of this system can be determined preoperatively with stereoangiograms or simple angiograms and Doppler audiometry. The anterolateral thigh fasciocutaneous flap is suitable for reconstruction of defects in an oral floor with tongue and esophageal deficits, scalp defects with dural defects, and for large full thickness defects of the lip. The advantages of this flap are safe elevation, a long and wide vascular pedicle, skin that is generally thin, and good pliability. Even if the skin is thick, a thinner flap can be created by sacrificing a large amount of fatty tissue. Furthermore, the skin territory is very wide and long. The donor defect can often be closed directly with its scar being less noticeable. The disadvantage of this flap is that the anatomy of the pedicle vessels has irregular derivation from the main vessels. This can be overcome, however, by employing preoperative stereoangiograms.

Adult↗

PubMed1993

Reinnervation of denervated Pacinian corpuscles: ultrastructural observations in rats following free nerve grafts.

Nerve transection and immediate free nerve grafts using rat sciatic nerves were employed to observe the morphologic changes in periodical denervation and reinnervation of Pacinian corpuscles located on the interosseous membrane between the fibula and tibia. During periods of from 2 weeks to 20 months after the surgery, a total of 28 corpuscles were obtained under an operating microscope and processed for morphologic analysis using light and electron microscopes. Based on our morphologic findings, normal corpuscles were composed of an axon terminal and inner and outer cores. The axon terminal disappeared within 2 weeks after the nerve grafts, but the original inner and outer core cells remained for up to 20 months. In addition, a small number of collagen fibrils was observed between the inner and outer core cells. After 4 months, multiple axon terminals began to regenerate in the inner core. From 7 to 20 months, these axon terminals in some corpuscles developed a structure resembling that of normal terminals. Some of these terminals were located in the center of the inner core, but a few were in contact with the outside of the inner core. The production of collagen fibrils in denervated corpuscles was periodically activated in the intercellular spaces. These findings suggest that the morphologic changes in denervated corpuscles correspond to those in denervated nerves. Inner core cells, which are continuous with Schwann cells, remain in their original condition in denervated corpuscles until regenerating nerves enter the inner core and are essential for corpuscle regeneration, because they may produce some trophic substances that induce the regeneration of multiple axon terminals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗