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Biomedical subjects

T S Chang

Publications and source records attributed to T S Chang.

At least 91 records · Page 5Linked to original sources
PubMed1989

Microwave: an alternative to electric heating in the treatment of peripheral lymphedema.

The results of a new method of treating chronic lymphedema with heat, using microwaves, are described in 98 patients with peripheral lymphedema. Thirteen had bilateral lymphedema and were included only to provide additional evidence of the lack of side-effects using this technique. The remaining 85 patients showed a significant (p less than .001) reduction in the amount of peripheral edema with edema reduction greater than 50% in three-fourths of the patients. The incidence and severity of secondary acute inflammation ("erysipelas") were also sharply reduced (p less than .001). The microwave method of heat application has a number of advantages over an older technique which used electrically-powered heating elements.

Arm↗
PubMed1988

The effect of sulfhydryl oxidation on the morphology of immature hamster epididymal spermatozoa induced to acquire motility in vitro.

Immotile spermatozoa from the caput epididymidis become progressively motile when incubated in medium containing theophylline, seminal plasma, and albumin. We previously reported that under these incubation conditions the spermatozoa induced to acquire motility exhibited a marked flagellar angularity, with the sperm head or midpiece bent 90-180 degrees towards the tail. In addition, we demonstrated that sperm flagellar bending did not occur when the sulfhydryl oxidant diamide was added to the motility induction medium. In the present study, we examined further the effect of sulfhydryl oxidation on the morphology and sulfhydryl content of immature caput spermatozoa induced to acquire motility in vitro. We found that flagellar bending was prevented and sperm flagellar straightness was maintained in a dose-dependent manner by diamide. Moreover, flow cytometric analysis of caput sperm sulfhydryls using the sulfhydryl reagent monobromobimane (mBBr) revealed that 1) diamide oxidizes caput sperm sulfhydryls, and 2) less than 15% of the total reactive sperm sulfhydryls were oxidized at diamide concentrations capable of preventing sperm angulation. Sodium tetrathionate (NaTT), another sulfhydryl oxidant, and hamster cauda epididymal fluid (CEF) containing sulfhydryl oxidase enzyme activity also maintained flagellar straightness in induced caput spermatozoa and oxidized sperm sulfhydryls. The flagellar straightness in caput spermatozoa treated with sulfhydryl oxidants, however, was temporary; with extended incubation, diamide- or CEF-treated spermatozoa exhibited flagellar bending. Additional studies showed that the flagellar straightness observed in sulfhydryl-oxidized spermatozoa was sustained when nitrofurantoin, an inhibitor of glutathione reductase, was included in the induction medium. Flow cytometric analysis of nitrofurantoin-treated spermatozoa showed that nitrofurantoin maintained the sperm disulfides formed by diamide and prevented the reduction of sperm disulfides back to sulfhydryls. Taken together, these studies demonstrate the significance of sulfhydryl oxidation in maintaining the morphology of immature caput epididymal spermatozoa induced to acquire motility in vitro and suggest that sulfhydryl oxidation may be important in the development of motility during sperm epididymal maturation in vivo.

Animals↗
PubMed1988

The application of free twin flaps in one-stage treatment of severe hand deformity.

Twin flaps from the plantar non-weight-bearing region and lower medial leg have been designed and performed in 7 patients, 1 of whom had bilateral twin flaps. The twin flaps possess different textures of tissues that are particularly suitable for repair of hand deformity involving both the palm and the dorsum. Technical points of raising twin flaps are detailed and their indications discussed.

Accidents, Occupational↗
PubMed1986

Induction and enhancement of progressive motility in hamster caput epididymal spermatozoa.

Progressive motility was induced in hamster caput epididymal spermatozoa incubated in Tyrodes medium containing 50 mM theophylline, 1.0% Fraction V bovine serum albumin, and 15% (v/v) heat-treated human seminal plasma. Under these induction conditions, however, the maximum percent of caput spermatozoa exhibiting progressive motility (21%) and the time during which motility was sustained (120 min) were significantly less (p less than 0.05) than that of controls from the cauda epididymidis. Moreover, in contrast to caudal spermatozoa, the majority of the induced caput spermatozoa exhibited some degree of flagellar bending at the neck or midpiece. In subsequent experiments the procedure for motility induction was modified to achieve levels of motility in caput spermatozoa equivalent to those observed for caudal spermatozoa. The addition of 5 microM diamide, a sulfhydryl oxidant, to the induction medium prevented the flagellar angularity observed in induced caput sperm preparations. The percentage of caput spermatozoa induced to progressive motility was increased to levels characteristic of caudal spermatozoa (48%) by the addition of hamster caudal epididymal fluid (CEF) to the induction medium. Finally, the viability of the induced caput spermatozoa was significantly enhanced (p less than 0.05) by the removal of Fraction V albumin from the induction medium. In the presence of CEF and in the absence of albumin, 50% of the caput spermatozoa acquired progressive motility and sustained this motility for 4 h. Moreover, when fatty acid-free, charcoal-extracted albumin instead of Fraction V albumin was utilized in the induction procedure, a maximum of 43% of the caput spermatozoa acquired progressive motility and maintained this motility for 4 h, suggesting that the decreased sperm viability observed in the presence of Fraction V albumin was due to a contaminant of albumin, possibly fatty acids. The studies described herein demonstrate for the first time that immature quiescent caput epididymal spermatozoa can be induced to acquire progressive and sustained motility equivalent to that observed in mature caudal epididymal spermatozoa.

Animals↗
PubMed1985

Tissue plasminogen activator and urokinase mediate the binding of Glu-plasminogen to plasma fibrin I. Evidence for new binding sites in plasmin-degraded fibrin I.

The effect of tissue plasminogen activator (TPA) or urokinase on the specific binding of human Glu-plasminogen to fibrin I formed in plasma by clotting with Reptilase was studied using 125I-plasminogen and 131I-fibrinogen. In the absence of TPA, small amounts of plasminogen were bound to fibrin I. TPA induced binding of plasminogen to plasma fibrin I that was dependent upon the concentrations of TPA and plasminogen as well as upon the time of incubation. Plasminogen binding occurred in association with fibrin clot lysis and the formation in the clot supernatant of alpha 2-plasmin inhibitor-plasmin complexes. Urokinase also induced binding of plasminogen to plasma fibrin I that was concentration- and time-dependent. The molecular form of plasminogen bound to the fibrin I plasma clot was identified as Glu-plasminogen by dodecyl sulfate-polyacrylamide gel electrophoresis and by fast performance liquid chromatography. Further studies demonstrated that fibrin I formed from fibrinogen that had been progressively degraded by plasmin-bound Glu-plasminogen. The mole ratio of plasminogen bound increased with the time of plasmin digestion. Glu-plasminogen did not bind to fibrin I formed from fibrinogen progressively digested by human leukocyte elastase, thereby demonstrating the specificity of plasmin. These studies demonstrate that plasminogen activators regulate the binding of Glu-plasminogen to fibrin I by catalyzing plasmin-mediated modifications in the fibrin substrate.

Densitometry↗
PubMed1985

Experiences in the clinical use of the medial genicular flap.

Four cases with defects at varying sites were reconstructed with the medial genicular flap. Three cases utilized free microvascular skin flaps based on the saphenous artery and one case a pedicled flap based on the same artery. All flaps survived well with satisfactory functional and cosmetic results. Regional anatomy is briefly reviewed, dissection of the flap is described in detail, and some special technical points are mentioned.

Adult↗
PubMed1985

Venous versus lymphatic duct autotransplantation in the treatment of experimental lymphedema.

Experimental autologous lymphatic duct transplantation is technically feasible and therapeutically effective in the treatment of chronic lymphedema of the extremity. However, we demonstrate that the risk of inducing lymphedema in the donor limb is evident; therefore, the clinical application of lymphatic transplantation is compromised. To obviate this risk, a vein graft was substituted in experimental animals with good prophylactic results. Postoperative lymphangiography showing free passage of contrast media through the interposed vein, rapid disappearance of acute lymphedema in the recipient limb (28.6%), and no risk of inducing lymphedema of the donor limb all favor the possibility of using a vein graft transfer in clinically treating chronic lymphedema of the extremity.

Acute Disease↗
PubMed1985

Experimental model of chronic limb lymphedema and determination of lymphatic and venous pressures in normal and lymphedematous limbs.

Experimental studies on chronic lymphedema of the extremities were performed using dogs, and an improved technique after the method of Danese in the preparation of chronic limb lymphedema is described. The incidence of chronic lymphedema in this model was 81.8%, whereas with Danese's method, it was only 66.7%. In addition, the measurement of lymphatic and venous pressure was studied in experimental animals. In the normal limb, the lymphatic pressure was always lower than the venous pressure, while in the chronic lymphedematous limb, the lymphatic pressure was higher than the venous pressure. Thus, after a lymphaticovenous anastomosis, a pressure gradient reversal exists between the two sides of the anastomosis. Although the high lymphatic pressure gradually dropped as the anastomosis became patent, ultimately the venous pressure was often higher than the lymphatic pressure. A venous back flow can be ensured by the anastomosis and the resulting thrombosis, which obstructs the lymphaticovenous anastomosis, is inevitable.

Animals↗
PubMed1985

Reversed island forearm fascial flap in hand surgery.

We present a technique using a reversed island forearm fascial flap based on the distal portion of the radial artery and veins, with a skin graft on top, to repair a soft tissue defect of the hand. Good results were obtained in a total of 18 operations in 17 postburn cases. The operation can be completed in one stage even when it involves the excision of scar tissue, correction of the secondary deformities of deep structures, and repair of the soft tissue defect of the hand. The advantages and disadvantages of the method and key points of the technique are discussed.

Adult↗
PubMed1985

One-stage reconstruction of esophageal defect by free transfer of jejunum: treatment and complications.

We report on 20 patients with esophageal defects that were reconstructed by jejunum transplant with the help of microsurgical techniques. Sixteen attempts were successful, for a success rate of 80%. Three types of reconstruction were used: free jejunum transfer, free jejunum flap transfer, and partially pedicled jejunum transfer with the distal portion revascularized. This article emphasizes the complications of these procedures, including tearing of the jejunum mesentery, thrombosis at the anastomotic stoma, balloon-like distention of the cervical portion of the transferred jejunum, strangulation at the diaphragm foramen, and stenosis of the anastomotic stoma between the remnant of the esophagus and the transferred jejunum. Measures for prevention and treatment of these complications are also discussed.

Burns, Chemical↗
PubMed1985

Vaginal reconstruction using labia minora flaps in congenital total absence.

A simplified technique using labia minora for total lining of the neovagina succeeded in 7 of our 10 patients with encouraging cosmetic and physiological results. In the remaining 3 patients, because of the smaller size of the labia minora, additional free skin grafts were necessary. The surgical technique, especially the surgical anatomy of the labia minora, is described in detail.

Adult↗
PubMed1984

Anterior urethral advancement: a one-stage technique for hypospadias repair.

This paper presents a new technique of repairing congenital hypospadias by a one-stage method using the principle of advancement of the anterior urethra. It can also be applied in the secondary repair of urethral strictures or fistulae. No urinary diversion is necessary. It eliminates the possibility of post-operative urethral stricture or fistula formation which are frequent complications of the more classical procedures and the repair can be completed in one stage. The clinical details of 16 patients in whom this technique was successfully used are presented.

Adult↗
PubMed1984

Forearm flap in one-stage reconstruction of the penis.

Seven cases of one-stage reconstructions of the penis with use of a free forearm flap have been successfully carried out with excellent cosmetic and functional results. Flap design and surgical techniques are described herein.

Forearm↗
PubMed1984

Aspirin inhibits vascular plasminogen activator activity in vivo. Studies utilizing a new assay to quantify plasminogen activator activity.

Vascular or tissue-type plasminogen activator (TPA) is a key enzyme in physiologic fibrinolysis. To study the role of prostaglandins in modulating the synthesis and release of TPA in vivo, we prospectively studied the effect of aspirin (650 mg/d X 2) on TPA activity in 13 human subjects before and after 10 min of forearm venous occlusion. TPA activity was quantified by a newly developed enzyme-linked immunosorbent assay that both measures and differentiates between TPA and urokinase (UK)-like plasminogen activator activity. This assay is based on the observation that the concentration of alpha 2-plasmin inhibitor-plasmin complexes in Reptilase-clotted plasma increases linearly in proportion to the amount of activator added. Resting TPA activity was higher in women than in men (0.56 +/- 0.59 vs. 0.15 +/- 0.11 U/ml, P = 0.049). Venous occlusion induced an eightfold rise in TPA activity in women (to 4.5 U/ml, P = 0.006) and a 15-fold rise in men (to 2.28 U/ml, P = 0.004), whereas UK activity was not detected. Aspirin inhibited the rise in TPA activity after venous occlusion by 69% in men (P = 0.004) and 70% in women (P = 0.014). In contrast, aspirin had no effect on pre- or post-occlusion hematocrits or Factor VIII-related antigen levels. There was no correlation between plasma salicylate level and percentage inhibition of TPA. Neither exogenous aspirin (0-1 microgram/ml) nor salicylate (0-70 micrograms/ml) inhibited the generation of alpha 2-plasmin inhibitor-plasmin complexes by exogenous TPA or interfered with the assay system. We conclude that aspirin may have an antifibrinolytic effect in man that has not been previously described.

Aspirin↗