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Biomedical subjects

C K Chou

Publications and source records attributed to C K Chou.

At least 127 records · Page 7Linked to original sources
PubMed1992

[Treatment of large skin defect with 6:1 meshed skin autograft and 1.5:1 meshed fresh porcine skin overlay].

The use of expanded mesh skin graft from limited donor sites has greatly increased wound coverage. However, grafts with an expansion size of 6:1 or greater often heal slowly or are lost because of local infection. Three patients with large skin defects in lower extremity have been treated with 6:1 mesh autograft overlayed by 1.5:1 fresh porcine skin mesh graft. Epithelium grown from both grafts could be found. The autografts continuously expanded under the xenografts. The outer xenografts gradually separated and desquamated, on an average, in 14 days. This technique enables resurfacing of a large area of skin defect from smaller donor sites.

Aged↗
PubMed1992

Microsurgical replantation of avulsed scalp--two cases report.

Two female patients with scalp avulsion were treated successfully by microsurgical replantation. The first patient suffered an avulsion of the right half of scalp and which survived fully after replantation. The second patient suffered avulsion of the entire scalp as well as the forehead skin and nape of the neck. Almost all of the avulsed part survived except partial skin loss in the posterior neck and left occipital area. Only one temporal artery and one vein was anastomosed in each case. Near normal hair growth recurred in both cases.

Adult↗
PubMed1992

Reconstruction of children's scalp defects with the Orticochea flap.

From January 1985 to February 1990, 4 children with scalp defects were selected for use of the Orticochea flap technique for reconstruction. The ages ranged from 15 months (the youngest in the literature) to 7 years. The defects ranged from 6 x 7 to 11 x 13 cm. Three defects were traumatic and 1 was acute lymphocytic leukemia septic emboli in cause. All these children got satisfactory results with follow-up periods ranging from 5 months to more than 5 years. With these preliminary experiences, we have verified that the Orticochea flap scalp reconstruction surgery described 20 years ago can be performed safely even in children, especially when tissue expansion is not suitable or readily available.

Child↗
PubMed1991

Overexpression of epidermal growth factor and insulin-like growth factor-I receptors and autocrine stimulation in human esophageal carcinoma cells.

The growth-stimulatory effects of epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and insulin-like growth factor-I (IGF-I) on the human esophageal carcinoma cell line CE48T/VGH were evaluated. Under serum-free conditions, EGF, TGF-alpha, and IGF-I promoted 3.6- to 4.1-fold increased cell proliferation. Scatchard analyses and Northern blot hybridization revealed that both the EGF/TGF-alpha receptor and the IGF-I receptor were overexpressed in CE48T/VGH cells. Furthermore, ligand-dependent autophosphorylation of the EGF receptor and the IGF-I receptor was clearly detected using antireceptor and antiphosphotyrosine antibodies. Autocrine regulation was strongly indicated by the following evidence: (a) CE48T/VGH cells were found to express TGF-alpha and IGF-I genes, (b) serum-free conditioned medium promoted the growth of CE48T/VGH cells and stimulated the autophosphorylation of the EGF/TGF-alpha receptor and the IGF-I receptor, and (c) the addition of IGF-I receptor antibodies significantly suppressed CE48T/VGH cell growth under serum-free conditions. Our studies suggest that the overexpression of EGF and IGF-I receptors and autocrine growth regulation may concertedly control the proliferation of esophageal carcinoma cells.

Animals↗
PubMed1991

Adipofascial turn-over flap for reconstruction of the dorsum of the foot.

Local adipofascial turn-over flaps with skin grafts were successfully used to reconstruct complicated skin defects over the dorsum of the foot in 7 patients. The blood supply of the flap comes from perforators in the base and from the surrounding subcutaneous and fascial plexuses. A new concept of base-to-flap area ratio is proposed to predict the survival of the turn-over flaps in addition to the conventional base-to-length ratio. This appears to be a valuable technique for difficult wounds of the dorsum of the foot.

Adult↗
PubMed1991

Microskin grafting of rabbits with pigskin xenograft overlay.

Pigskin xenografts were used to replace allografts in microskin grafting (10:1 expansion ratio) on 15 rabbits. Rabbits were selected randomly for the removal of the overlaid pigskin at days 7, 10 or 14 for the evaluation of the degree of epithelialization. Histological examination of the removed pigskin 7 days after application showed obvious eosinophilic changes in the epidermal cells and pyknotic changes of the nuclei, however in some areas newly formed epidermis could be found. The pigskin became an eschar or slough on day 14. The microskin autografts proliferated and expanded actively under the protection of this overlaid pigskin. The epidermis increased in thickness and with increasing differentiation. The dermal layer was well vascularized with a large number of capillaries and fibroblasts. The wound was covered by the neoepithelium with almost normal skin texture on day 14, by which time the overlaid pigskin became a dry eschar. In areas where the overlaid pigskin was sloughing, the epithelialization of the underlying microskin grafts was not complete at the same time. In these animal studies of microskin grafting, these overlaid pigskin xenografts showed the same effects as those of allografts.

Animals↗
PubMed1991

Use of a cross-leg free muscle flap to reconstruct an extensive burn wound involving a lower extremity.

A young patient sustained a high-voltage burn with extensive destruction of the soft tissue in his left lower extremity. Occlusion of the anterior and posterior tibial arteries, loss of toe extensors and the superficial and deep peroneal nerves were noted, besides the exposure of the lower end of the tibia and metatarsal bones. In the absence of proper recipient vessels, a cross-leg free latissimus dorsi muscle flap with overlying skin and depending on the vessels of the contralateral foot was used successfully for reconstruction of the defect. The pedicle was divided 3 weeks after microvascular anastomosis and the flap survived completely. This technique permits transfer of free flaps to compromised wounds without available recipient vessels, and the latissimus dorsi muscle flap, with its characteristics of large size and copious vascularity, could be split to cover exposed bones in different areas simultaneously.

Adult↗
PubMed1991

Management of hypertrophic scars on the pubic area with an iliac flap.

Postburn hypertrophic scars on the pubic area are rare. A local iliac flap has been used in four female patients for covering the raw areas after total excision of these scars. The largest flap in this series was 7 x 13 cm. Although bilateral flaps could be used simultaneously, only a unilateral flap was used in each patient. All the donor sites were closed primarily. The postoperative course was uneventful in each patient. Itching subsided completely in all patients and distortions of the genitalia were corrected. There was no recurrence of the scar formation in the follow-up period from 2 to 7 years. The only drawback of this flap for coverage of the symphysis pubis is that it is hairless. The experience with the present patients proved that this is an easy, quick and reliable method for removing hypertrophic scars on the pubic area.

Burns↗
PubMed1991

Limb salvage of infected diabetic foot ulcers with microsurgical free-muscle transfer.

This study was comprised of 9 diabetic patients with 10 infected foot ulcers, including osteomyelitis in 4 limbs and gangrene in 3 limbs. Adequate debridement of these complicated wounds inevitably resulted in exposure of bones or tendons. All defects were successfully reconstructed with free gracilis muscle flaps covered with split-thickness skin grafts. No recurrence of ulcer or infection was noted in the muscle-transplanted area during the follow-up period. Laser Doppler perfusion monitor measurement showed that the perfusion unit of the denervated free muscle flap increased to a peak at the second week after transplantation; the neovascularization of the grafted skin, the progressive decrease of the muscle swelling, and the decreased interstitial pressure may be the main contributing factors. The perfusion unit of the muscle flap reached equilibrium with the surrounding tissue at about 8 weeks after microsurgical transfer. Lower extremity amputation is a major health problem in the diabetic population. The microvascular free-muscle transfer was proved to play an effective and important role in limb salvage in diabetic patients with infected foot ulcers. The gracilis muscle flap was recommended due to its lack of bulkiness and minimal donor site deformity.

Aged↗
PubMed1991

cAMP and vascular action of endothelin.

Endothelin, a potent vasoconstricting peptide, induced maximal contraction of the rat tail artery within 3 min of administration. Endothelin also caused a dose-dependent decrease in tissue levels of cAMP. Concentrations of cAMP decreased about 60% 1 min after endothelin (10(-8) M) administration, but returned to basal levels in 5 min. By contrast, tissue levels of cGMP were not changed by endothelin. Modulation of cAMP production may provide one mechanism for the vascular action of endothelin.

Animals↗
PubMed1991

[Surgical treatment of diffuse scrotal epidermal cysts: case report].

Epidermal cysts are common, benign skin tumors that are found mainly on the face, neck, and trunk. This case was a 53-year-old male bus driver who had suffered from multiple papules on his scrotum for 7 years. This affliction had caused intractable itching and responded poorly to medical treatment. The patient received an excision of these papules (total 32) 3 years ago. According to the pathological reports, these papules were epidermal cysts; unfortunately, these papules recurred within 3 months after the operation and then resulted in itching more severe than before. The patient was again admitted to the hospital ward and received an operation in Oct. 1990. The diseased tissue (14cm x 8cm) was then excised and the defective scrotal skin was covered with a meshed, split-thickness skin graft. The cosmetic result was enhanced by the rugate appearance of the healed meshed graft. The patient was satisfied with both the functional and cosmetic results. The itching sensation on the scrotum improved and there was no recurrence of epidermal cysts within the graft area during the 9 month follow-up period. With this simple and safe operation, the result gave a satisfying improvement in both symptoms and appearance; so this case is offered for reference.

Epidermal Cyst↗
PubMed1990

Elevation of facilitated glucose-transporter messenger RNA in human hepatocellular carcinoma.

Complementary DNA of a rat brain glucose transporter gene was used to examine the expression of glucose-transporter messenger RNA in paired human hepatocellular carcinomas and adjacent nontumorous liver tissues, as well as in human hepatoma cell lines and human fetal liver samples. High expression of a major 2.8-kilobase glucose-transporter transcript was seen in all hepatoma cell lines and fetal liver samples examined, whereas a much lower level of expression was observed in liver tissues. When pairs of liver tissues were examined, elevation of glucose-transporter RNA levels was observed in most of the hepatocellular carcinoma tissues examined.

Animals↗
PubMed1990

Immediate reconstruction of the penis with an iliac flap.

Immediate reconstruction of the penis can save time and significantly reduce postoperative psychological morbidity. A patient suffered a cancerous lesion in his glans penis. After total amputation, an iliac flap based on the superficial circumflex iliac artery was used to reconstruct the penis. The subcutaneous tissue around the vascular pedicle was carefully preserved for enhancing the venous drainage of the new penis. A self-sculptured silicone implant was inserted later to increase the penile rigidity. The advantages of this technique include ready availability, easy mobilisation, hairlessness, elimination of multi-staged procedures, and saving time. The patient is pleased with the operative results.

Amputation, Surgical↗
PubMed1990

The role of receptor kinase in insulin action and the effects of insulin on human hepatoma cells.

Insulin has both short- and long-term effects on cellular metabolism. The short-term effects are known to involve the insulin receptor, a protein kinase capable of phosphorylating itself and other proteins. The role of the receptor was elucidated by studies of a mutant insulin receptor which lacked kinase activity and inhibited several actions of insulin. The long-term effects of insulin could be demonstrated by its growth-promoting effect on hepatoma cells, and by the suppression in transfected hepatoma cells of hepatitis B virus antigen production in a dose-dependent manner. The process whereby insulin appears to regulate gene expression is not clearly understood.

Cell Division↗
PubMed1990

Effects of endothelin and vasopressin on portal pressure of rats.

Endothelin is a vasoconstrictor peptide which has recently been isolated and sequenced from the vascular endothelial cells. It was reported to increase blood pressure in vivo and produce a prolonged contraction with a slow onset in vitro. The purpose of this study was to investigate whether endothelin can lower the portal pressure as another endogenous vasoconstriction peptidevasopressin (AVP) can. Heart rate, systemic blood pressure, portal pressure, and portal vein blood flow were measured. Effects of endothelin on these parameters were compared with those of AVP. Endothelin 10(-10) mol/Kg significantly decreased all of the parameters mentioned. At the higher dose (5 x 10(-10) mol/Kg), however, the portal pressure and blood pressure were increased and portal vein blood flow was unchanged. On the other hand, AVP decreased the portal pressure and portal vein blood flow but elevated the systemic blood pressure. In vitro experiments revealed that endothelin contracted both tail artery and portal vein of rat and vasopressin contracted only tail artery. We concluded that although both are endogenous vasoconstricting peptides, endothelin and AVP affect differently on arterial and venous vascular beds as well as on portal pressure.

Animals↗
PubMed1990

Effects of fat thickness on heating patterns of the microwave applicator MA-151 at 631 and 915 MHz.

Previous studies showed that the surface heating patterns of the MA-151 applicator on a 2 cm fat and 10 cm thick muscle phantom had center heating at 581 and 930 MHz and two hot spots near the edges of the applicator at 657 and 779 MHz. The hot spots at 657 MHz were consistent with two blisters on a patient's thigh. Since the heating patterns on muscle only showed good center elliptical heating at all frequencies, in this study we have investigated the effects of fat thickness on the heating patterns. Thermograms of fat and muscle surfaces were taken on phantoms with 0, 0.25, 0.5, 1, and 2 cm thick fat exposed to 631 or 915 MHz energy. The 631 MHz was selected to provide reasonable energy coupling for all phantoms. At 631 MHz, two hot spots were evident on all fat surfaces. The pattern on the muscle surface under the 0.25 cm fat did not show two hot spots, but the heating was elongated in the E-field direction. At 915 MHz, the heating was elongated on the surface of the 0.25 and 2 cm fat, and two hot spots were observed on the 0.5 and 1 cm fat surfaces. However, the muscle heating was elliptical in all cases. The ratio of muscle to fat heating decreased as the fat thickness increased. At 0.5 cm fat the ratio was about 1. These results indicate that fat thickness influences heating in muscle. During treatment with this applicator, surface temperature probes should be placed over potential hot spots. Surface cooling is desirable for heating tumors beneath the fat.

Adipose Tissue↗
PubMed1990

V-Y advancement flap for facial defects.

V-Y advancement flaps based on subcutaneous pedicles are an ideal option for closure of small to medium sized facial defects. This technique has been used to treat 69 patients with various lesions of the face, (30 basal cell carcinoma, 9 squamous cell carcinoma, 18 nevus, 4 traumatic defect, 3 old scar and 5 others) during the past seven years. There was no necrosis of any single flap. All the designs could be planned so that the long axes of the flaps were parallel to the wrinkle line, contour line or line of dependency. All wounds healed uneventfully with fine or undelineated scar. There were no secondary operation for these cases. Clinical results of this series have shown advantages of this flap in reconstruction of facial defects. It is reliable in circulation and is easy to design and execute. It causes no distortion of critical features and offers excellent cosmetic satisfaction in color and texture matching. Therefore, the V-Y advancement flap is recommended for closure of properly selected facial defects.

Adolescent↗