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Biomedical subjects

C K Chou

Publications and source records attributed to C K Chou.

At least 91 records · Page 5Linked to original sources
PubMed1995

Reconstruction of the totally degloved little finger with a bilobed digital neurovascular island flap.

Treatment of a completely degloved finger injury is a challenge to plastic surgeons. We used a simple method, a bilobed digital neurovascular island flap harvested from the dorsolateral side of the middle and proximal phalanges of the ring finger, to reconstruct the complete degloved little finger. This method provides a one-stage operation for coverage of the degloved little finger and also results in good sensation and an acceptable appearance.

Adult↗
PubMed1995

Clinical application of the distally based medial adipofascial flap for soft tissue defects on the lower half of the leg.

OBJECTIVE: Reconstruction of soft tissue defects on the lower half of the leg. DESIGN: The distally based medial adipofascial flap nourished by the lower perforator originating from the posterior tibial artery was harvested, and the pivot point of flap transposition is 9 to 12 cm above the tip of the medial malleolus. MATERIALS AND METHODS: Twelve cases of open tibial fracture associated with soft tissue defects on the lower half of the leg were reconstructed with this flap. The cases consisted of ten males and two females, and their ages ranged from 16 to 71 (averaging 41 years). MEASUREMENTS AND MAIN RESULTS: Size of the flap varied from 4 x 7 cm to 5 x 18 cm. Eleven flaps had good perfusion and survived completely. Tip necrosis of the flap occurred in one case. In the early postoperative period, take of the meshed split-thickness skin graft on the flap was not complete. All wounds, however, were resurfaced completely without the need of a second grafting. Discharging sinuses occurred in one case, which was managed by removal of infected bony fragments. All the donor sites were closed primarily, and desquamation of wound edges occurred occasionally. CONCLUSIONS: The distally based medial adipofascial flap was a reliable and effect local flap for the reconstruction of soft tissue defects on the lower half of the leg.

Adolescent↗
PubMed1995

Differential pathways of insulin action upon the hepatitis B surface antigen gene expression and cell proliferation in human hepatoma cells.

We have shown previously that insulin at the physiological concentration suppresses hepatitis B surface antigen (HBsAg) gene expression in cultured human hepatoma Hep3B cells, and this suppression phenomenon is concomitant with the stimulation of cell proliferation. We have now examined whether these two distinct insulin actions on the Hep3B cells are mediated through the same or different signaling pathways. After prolonged treatment with high concentration of tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA), the protein kinase C-alpha (PKC-alpha) level in the Hep3B cells was diminished and could not be detected by Western blot analysis. Under this condition, TPA treatment has no effect on the number or affinity of the insulin receptor on Hep3B cells. However, insulin-stimulated cell proliferation was completely abolished in the PKC-alpha depleted cells. In contrast, insulin still suppressed HBsAg gene expression with the same ED50 (approximately 0.5 nM) as the control cell. The induction of proto-oncogene egr-1 (early-growth-regulatory-1) by insulin and TPA under similar conditions were also examined. Both insulin and TPA stimulated egr-1 gene expression up to 10-fold in the control cell, but neither of these two agents showed any effect on egr-1 gene expression in the PKC-alpha down-regulated Hep3B cells. These observations indicate that the PKC-alpha may be involved in the insulin induced egr-1 expression and cell proliferation but not in the insulin suppressed HBsAg gene expression in human hepatoma cells.

Carcinoma, Hepatocellular↗
PubMed1995

A clinical analysis of necrotizing fasciitis: a review of 54 cases.

Necrotizing fasciitis is a severe and sometimes life-threatening soft tissue infection that is characterized by rapidly widespreading necrosis of fascia and subcutaneous tissue. Fifty-four cases of necrotizing fasciitis were reviewed over a 5-year period. Among them, 25 patients (46%) had diabetes mellitus. The majority of the wound bacterial cultures (71%) yielded a mixed growing. There were negative cultures in six patients, and single organism growth in 14 patients (29%). The predominant organisms growth were Streptococci, Staphylococci, and Escherichia coli. The overall mortality rate was 22% (12/54). Death was caused by systemic septic complications in these patients. All 12 mortalities resulted from delayed debridement (averaging 25 days after initial symptoms appeared). Our study indicates that the early recognition and prompt debridement of all necrotic tissue is essential for reducing the mortality rates of this potentially lethal condition.

Adolescent↗
PubMed1994

Character of the effect of microwave on conduction velocity of frog ventricular muscle.

Thirty-two frog hearts were divided into four groups and placed individually in temperature-controlled waveguides filled with Ringer's solution. The pacemaker was removed, and stimulation was provided at 0.3 Hz by three carbon-loaded Teflon electrodes located on the aorta and the ventricular muscle. Conduction velocity was measured from the difference between two action potentials. One group served as control; the three other groups were exposed for 2 h to pulsed 2,450 MHz microwave fields (10 microseconds, 0.001 duty cycle, 16 Hz modulation) at specific absorption rates (SARs) of 0.003, 2, and 6 W/kg, respectively. No significant difference in conduction velocity was found between the control and the exposed groups.

Animals↗
PubMed1994

The reverse lateral arm flap, based on the interosseous recurrent artery, for cubital fossa burns.

The reverse lateral arm flap based on the interosseous recurrent artery was used successfully to reconstruct cubital fossa defects caused by high voltage electric burn in two cases. The flap is nourished by the septocutaneous perforators of the posterior radial collateral artery which anastomoses around the lateral epicondyle with the interosseous recurrent artery. The primary benefits of this flap are that it is an easy and rapid one-stage procedure, with no necessity of sacrificing a main artery or local muscle, and it requires no immobilisation of the involved joint.

Adolescent↗
PubMed1994

A mixture of allogeneic and autologous microskin grafting of rabbit skin wounds with Biobrane overlay.

A mixture of allogeneic and autologous microskin grafts (10:1 expansion ratio) were transplanted and overlain with Biobrane, on to full-thickness skin wounds (8.0 x 5.0 cm in size) in 16 rabbits. They were divided into two groups: in group I, the expansion ratio of both allo- and autograft was 20:1; in group II, the expansion ratio of allo- and autograft was 15:1 and 30:1 respectively. On day 9, all wounds of group I and II were almost completely resurfaced with neoepithelium. There was no serious rejection reaction within the neoepithelium and the wounds were maintained completely resurfaced after day 9. There were scales on the epithelialized wound which were more numerous in group II than in group I. Histological examination revealed that these wounds were resurfaced with well-differentiated epithelium which contained two different histological patterns. They were identified as the survived transplanted allogeneic and autologous microskin grafts, each having their own characteristic histological features and different sex chromosome. Thus both the largely expanded allogeneic and autologous microskin grafts could proliferate together and contribute to the resurfacing of the wound. With this method, the rabbit skin wound could be resurfaced completely after the ninth postoperative day with markedly minimized amounts of autologous and allogeneic grafts.

Animals↗
PubMed1994

An easy way to prepare microskin grafts.

The conventional technique to produce microskin grafts is a relatively time-consuming procedure. We developed an easy method by using a trimmed circular dermacarrier with the non-grooved side up and driving forward in the meshgraft instrument through six different angles that were 30 degrees apart. The tiny skin particles obtained by this method not only saved operation time but also survived well in the grafted wounds.

Adult↗
PubMed1993

Retinoic acid biphasically regulates the gene expression of hepatitis B virus surface antigen in human hepatoma Hep3B cells.

We used human hepatoma Hep3B/C16 cells as a model to examine the effect of all-trans retinoic acid on the gene expression of hepatitis B surface antigen (HBsAg). Hep3B/C16 is a clonal derivative of human hepatoma Hep3B cell which was stably transfected with HBsAg DNA sequences and can produce hepatitis B virus surface antigen. We analyzed the HBsAg product and mRNA in Hep3B/C16 cells which were exposed to retinoic acid for different periods of time. The level of HBsAg started to increase after 24 h and reached maximum at 48 h of retinoic acid treatment. However, the level of HBsAg expression was severely suppressed compared to the control cells after long term (120 h) retinoic acid treatment. Such biphasic regulation of HBsAg production by retinoic acid was paralleled by the changes of HBsAg mRNA. Nuclear run-on assays also demonstrated that the retinoic acid-mediated regulation was determined at least in part at the transcriptional level. Furthermore, an exposure of the cells to retinoic acid for only 8 h was sufficient to show that up- and down-regulation of HBsAg gene occurred 2 and 5 days later. Using a transient expression system, we demonstrated that the retinoic acid response element is located within the 5'-flanking region of the HBsAg gene.

Gene Expression Regulation, Viral↗
PubMed1993

MRI demonstration of peritoneal ligaments and mesenteries.

The normal appearances of 14 peritoneal ligaments and mesenteries were demonstrated by magnetic resonance imaging (MRI). Antegrade or retrograde air introduction was employed to distend and mark the gastrointestinal tract. Delineation of these ligaments and mesenteries was helped by the presence of ascites and air-distended bowel loops. The different intraperitoneal compartments are also demonstrated.

Humans↗
PubMed1993

The use of MRI in bowel obstruction.

Nine patients with clinical or radiographic evidences of bowel obstruction were examined by magnetic resonance imaging. Retrograde insufflation of 1000-1200 ml of air through a Foley catheter placed in the rectum was employed. Scopolamine was used to inhibit bowel peristalsis and possibly relax the ileocecal valve. The administered air successfully distended the colon and the small bowel distal to the obstruction in seven of the nine cases. The air-filled small bowel loops were useful in delineating the obstruction sites and adjacent lesions in these seven cases. The diagnosis was established by means of surgery in six cases and by clinical course in three cases. The causes of obstruction included four peritoneal carcinomatoses, and one each of supravesical hernia, intussusception, adhesive band, benign granulomatous stricture, and radiational stricture. The site of obstruction was the distal small bowel in eight cases, and the rectosigmoid colon in one case.

Female↗
PubMed1993

Abdominal MR imaging following antegrade air introduction into the intestinal loops.

Air was used to distend the gastrointestinal tract and act as a contrast medium to effectively delineate the other abdominal organs/masses and to outline intraluminal or mural lesions. We used a nasogastric tube to introduce air into the stomach. Metoclopramide was administered to propel air throughout the gastrointestinal tract. Bowel peristalsis was then controlled by scopolamine butylbromide. Most of the alimentary tract could be distended by air. The normal bowel walls were barely visible between intraluminal signal-void air and extraluminal high-signal fat. Intraluminal tumor, wall thickening, and adjacent structures could be clearly delineated.

Adolescent↗
PubMed1993

Retrograde air insufflation in MRI: a technical note.

Retrograde air insufflation was employed to distend the colon and the ileum in 18 patients and five volunteers for magnetic resonance examination. Good and moderate marking of the ileum was obtained in 18 cases. The colon was nearly completely distended in every case. Intraluminal tumor, mural thickening, and extraluminal lesion were outlined by intraluminal air and surrounding air-distended bowel. This study shows that retrograde air insufflation is a useful method to mark the colon and most parts of the ileum.

Adult↗
PubMed1993

Innervated reverse digital artery flap through bilateral neurorrhaphy for pulp defects.

To provide sensation to the reverse digital artery (RDA) flap, both the dorsal branch from the proper digital nerve and the superficial sensory branch from the corresponding radial or ulnar nerve are sectioned at their proximal ends and included with the RDA flap. These are then anastomosed with the distal ends of both radial and ulnar digital nerves at the recipient wound. Three cases of pulp defects reconstructed by this technique achieved very favourable functional and cosmetic results. The RDA flap, innervated through bilateral neurorrhaphy, seems to be an excellent option for one-stage reconstruction of major pulp defects.

Adolescent↗
PubMed1993

Effect of an extract from Phyllanthus amarus on hepatitis B surface antigen gene expression in human hepatoma cells.

It has been suggested that Phyllanthus amarus may be helpful in the treatment of hepatitis B virus infection. We studied the effect of an aqueous extract of P. amarus on the cultured hepatoma cell line HepA2. This cell line had been transfected with tandemly arranged HBV DNA and continued to synthesize and secrete both HBsAg and HBeAg. Extract of P. amarus reversibly inhibited cellular proliferation and suppressed HBsAg production but not HBeAg production in HepA2 cells. We also found that P. amarus suppressed HBsAg gene expression at mRNA level in a time-dependent manner, and selectively abolished the HBsAg gene promoter driven CAT activity. Our results demonstrate that P. amarus contains some active components which can suppress the HBsAg gene expression in human hepatoma cells. Such suppression may contribute the antiviral activity of P. amarus in vivo.

Animals↗
PubMed1993

Clinical application of adipofascial turn-over flaps for burn wounds.

Local adipofascial turn-over flaps overlaid with skin grafts were used successfully to reconstruct nine deep burn wounds following electric injuries or contact burns in seven patients. Durable flap coverage of the exposed tendons, joints or bones can be achieved with a one-stage procedure. Appropriate length-to-width ratio and flap-to-base area ratio, and the tension-free insetting of the flap are essential for flap survival. The non-adherent characteristic of the adiposal component of the flap enables the underlying involved tendons or joints to glide through without adherence, and the rich vascular network in the fascia provides an ideal bed for the skin graft. The adipofascial turn-over flap is a reliable and simple technique for reconstruction of certain deep burn wounds if the surrounding soft tissue is available. The functional and cosmetic results in our series have been rewarding and satisfactory.

Adipose Tissue↗
PubMed1993

Allogeneic microskin grafting of rabbits' skin wounds.

Allogeneic microskin grafts (expansion ratio of 10:1), overlain with Biobrane, were applied to 30 rabbits. There were two groups. In group I, the allogeneic donor microskin grafts were transplanted without specific management. In group II, the donor skin was treated with ultraviolet (312 nm) irradiation to depress Langerhans cells immediately before the transplantation. Histological examination of these grafted wounds in the early stage showed that these micrografts proliferated actively with increased mitotic figures and became regularly stratified under the conditions provided by the Biobrane. By day 9, these wounds in group I were almost resurfaced with neoepithelium. In group II, the rate of regeneration of the neoepithelium was slower than those of group I. Subsequently there was rejection with moderate mononuclear infiltration, hydropic degeneration and satellite necrosis of basal and suprabasal keratinocytes, and local destruction of epithelium. Grossly these reactions caused 'melting' of the neoepithelium and resulted in raw areas. These rejections were more severe about 2 weeks after transplantation and then subsided gradually. Mild cellular infiltration continued to prevent the formation of rete ridges and the dermoepidermal junction was smooth at all times. Langerhans cells could not be found in these grafted wounds using OKT-6 and S100 stain. In spite of the destruction caused by these rejections in both groups, 25 wounds were completely resurfaced with well-differentiated neoepithelium by day 21. This study revealed that the transplanted allogeneic microskin grafts could proliferate to form neoepithelium and resurface the skin wounds of rabbits.

Animals↗