Biomedical subjects

C K Chou

Publications and source records attributed to C K Chou.

At least 109 records · Page 6Linked to original sources

PubMed1993

Aspergillosis complicating the grafted skin and free muscle flap in a diabetic.

A case of infected diabetic foot ulcer was reconstructed by a free muscle flap overlaid with a skin graft. Primary cutaneous aspergillosis involving the grafted skin and the transplanted muscle was described. The patient presented with an indurated grey-yellow plaque or black eschar in the wound without purulent discharge. Biopsies and cultures demonstrated A. flavus as the etiologic agent without evidence of systemic dissemination. Early diagnosis necessitates a high index of suspicion in immunocompromised patients with unusual cutaneous manifestation. Treatment consisted of aggressive debridement, systemic and local antifungal therapy, and delayed grafting. We concluded that primary cutaneous aspergillosis may occur at the reconstructed wound in an immunocompromised diabetic, and that it is a rare complication requiring prompt diagnosis and treatment.

Aspergillosis↗

PubMed1993

Tracheal deviation: an unusual complication of platysma myocutaneous flap.

Reconstruction of the intraoral defect caused by tongue cancer was done for a patient by using a platysma myocutaneous flap. The relatively short neck, scar contracture, and inactive movement of the involved side of the neck resulted in tracheal deviation, an unusual complication not appearing in previous reports. In order to avoid airway problems during intubation, the surgeon and anesthestist should seriously consider the possibility of this rare complication in patients who have had the platysma myocutaneous flap technique. Careful preoperative evaluation and skillful intubation of the fiberoptic bronchoscope are demanded in cases where next general anesthesia is needed.

Adult↗

PubMed1993

The subgalea-periosteal turnover flap for reconstruction of scalp defects.

Subgalea-periosteal flaps were successfully used in a turnover pattern to reconstruct two scalp defects with exposed calvaria caused by tumor ablation. A copious vascular network of the subgaleal fascia in the base and its attached lateral territories provide adequate blood inflow for the turnover flap. The periosteum is included in the flap to protect the blood supply of the subgaleal component from damage during dissection, and its uniform surface constitutes an ideal bed to receive skin grafts. The tissue is readily available and a large flap can be created in a single surgical step without deformities or sequelae left in the donor area. The subgalea-periosteal turnover flap overlaid with skin graft seems to make reconstruction of the complicated scalp defect much simpler and straightforward.

Adult↗

PubMed1993

Management of windshield facial injuries.

Between Jan. 1986 and Dec. 1990, 99 patients with automobile windshield facial injuries were hospitalized in Kaohsiung Medical College hospital. All patients were injured by old type windshields in car accidents. Seventy-three patients (74%) were male and twenty-six (26%) were female. Ages ranged from 6 to 62 years (mean age 31 years). Fifty-seven patients (58%) were car drivers and forty-two (42%) were front seat passengers. All patients had typical multiple U-shaped lacerations on the face. The major injury sites were localized to the upper one third of the face. The wounds were repaired immediately after careful debridement. A total of 21 facial bone fractures were noted. All were open fractures with large, deep avulsion wounds. Displaced and comminuted fractures received reduction and fixation before wound closure. Three patients had cranial bone fracture with no displacement. Brain edema and subarachnoid hemorrhage were found by brain CT scan in two and one patients respectively. They were treated conservatively. In one patient with frontal sinus fracture the glass pieces penetrated into the brain. The foreign bodies were removed from the brain and frontal sinus. Eyeball rupture was found in 16 patients, including two patients in whom both eyes were involved. Eight eyeballs needed immediate evisceration and ten eyeballs received reparation. Blindness occurred in all these patients. Of the 99 patients in this study, 15% sustained additional injury. Most were wounds on the extremities. Because serious injuries can be caused by the old type of windshields, it should be abandoned. Driving with the seat belt fastened is the best way to insure safety.

Accidents, Traffic↗

PubMed1993

Flow cytometric study of anterior chamber aqueous humor after neodymium: yttrium aluminum garnet laser iridotomy.

Laser iridotomy is a safe and effective treatment of pupillary-block glaucoma; however, increased intraocular pressure (IOP) may occur after the procedure. A flow cytometric study of aqueous humor was done 1.5 hours after neodymium: yttrium aluminum garnet laser iridotomy in 20 eyes. This sensitive and precise method did not reveal an apparent correlation between the degree of postoperative IOP spike and the amount of inflammatory cells or cellular debris induced by laser iridotomy. Although slit-lamp examination showed many "cells" in the anterior chamber in most after laser iridotomy, DNA histography found only scanty chromatin coating cells. We believe the so-called cells observed using slit-lamp biomicroscopy might not all be real cellular aggregates but rather aggregates of protein or fibrin in some situations.

Acute Disease↗

PubMed1992

Transcriptional regulation of transferrin and albumin genes by retinoic acid in human hepatoma cell line Hep3B.

Transferrin and albumin, which are both secreted from the human hepatoma cell line Hep3B, were regulated transcriptionally by retinoic acid (RA) in a dose-dependent manner. The cell growth rate was little affected under the same conditions. The treatment of Hep3B cells with RA (10 microM for 48 h) resulted in an 8-fold increase in transferrin protein synthesis, a 10-fold increase in the steady-state transferrin mRNA level, and a 5-fold increase in its transcriptional rate. The same treatment led to 4-fold decrease in albumin synthesis, as well as a 7-fold decline in the steady-state albumin mRNA level and a 4-fold decrease in the transcriptional rate. Cycloheximide and actinomycin D blocked the action of RA, suggesting that RA may regulate transferrin and albumin gene expression indirectly in human liver cells.

Blotting, Northern↗

PubMed1992

In vitro apoptosis in the human hepatoma cell line induced by transforming growth factor beta 1.

The effect of transforming growth factor beta 1 (TGF-beta 1) on human hepatoma cells (Hep 3B) was studied. Cell death was observed when the serum starved Hep 3B cells were exposed to a very low concentration of TGF-beta 1. The half-maximal cytocidal concentration of TGF-beta 1 was around 20 pM. Cell death began approximately 24 h following treatment, with more than 80% of the cells dying after 48 h. In contrast, the control cells, which were cultured in serum-free condition, still gradually proliferated. Furthermore, the cytocidal effect of TGF-beta 1 on Hep 3B cells was not altered by either cycloheximide or actinomycin D. It was discovered, using diphenylamine assay, that TGF-beta 1 induced DNA fragmentation in Hep 3B cells. Using gel electrophoresis, the fragmented DNA could be displayed, and showed a characteristic stepladder pattern. Thus, it appeared that TGF-beta 1 induced a particular pathway in Hep 3B cells in which de novo protein synthesis was not actively involved, but endogenous nuclease was activated which cleaves cellular DNA and induces cell death.

Carcinoma, Hepatocellular↗

PubMed1992

Long-term, low-level microwave irradiation of rats.

Our goal was to investigate effects of long-term exposure to pulsed microwave radiation. The major emphasis was to expose a large sample of experimental animals throughout their lifetimes and to monitor them for effects on general health and longevity. An exposure facility was developed that enabled 200 rats to be maintained under specific-pathogen-free (SPF) conditions while housed individually in circularly-polarized waveguides. The exposure facility consisted of two rooms, each containing 50 active waveguides and 50 waveguides for sham (control) exposures. The experimental rats were exposed to 2,450-MHz pulsed microwaves at 800 pps with a 10-microseconds pulse width. The pulsed microwaves were square-wave modulated at 8-Hz. Whole body calorimetry, thermographic analysis, and power-meter analysis indicated that microwaves delivered at 0.144 W to each exposure waveguide resulted in an average specific absorption rate (SAR) that ranged from 0.4 W/kg for a 200-g rat to 0.15 W/kg for an 800-g rat. Two hundred male, Sprague-Dawley rats were assigned in equal numbers to radiation-exposure and sham-exposure conditions. Exposure began at 8 weeks of age and continued daily, 21.5 h/day, for 25 months. Animals were bled at regular intervals and blood samples were analyzed for serum chemistries, hematological values, protein electrophoretic patterns, thyroxine, and plasma corticosterone levels. In addition to daily measures of body mass, food and water consumption by all animals, O2 consumption and CO2 production were periodically measured in a sub-sample (N = 18) of each group. Activity was assessed in an open-field apparatus at regular intervals throughout the study. After 13 months, 10 rats from each group were euthanatized to test for immunological competence and to permit whole-body analysis, as well as gross and histopathological examinations. At the end of 25 months, the survivors (11 sham-exposed and 12 radiation-exposed rats) were euthanatized for similar analyses. The other 157 animals were examined histopathologically when they died spontaneously or were terminated in extremis.

Animals↗

PubMed1992

Evaluation of microwave hyperthermia applicators.

Hyperthermia has been used in conjunction with radiation and chemotherapy for cancer treatment. When using electromagnetic heating, applicators are critical components in contact with or in proximity to patients and can be the determining factor for effective and safe treatment. Tissue absorption of electromagnetic energy is determined by many factors. Three cases are shown to illustrate the complexity of microwave heating: 1) The BSD MA-151 applicator has good center heating on a muscle-only phantom as shown in the operation manual. When fat slabs of 0.25, 0.5, 1, and 2 cm thick were added, two hot spots near the periphery of the applicator were evident on all fat surfaces, exposed at 631 MHz. At 915 MHz, the heating was elongated on the surface of the models with 0.25- and 2-cm fat, and two hot spots were observed on the 0.5- and 1-cm fat surfaces. 2) Heating patterns of the Clini-Therm applicators on a muscle-only phantom, as indicated in the operations guide, are elliptical with their major axes perpendicular to the electric field. However, when a bolus is used, the elliptical pattern is parallel to the E field. 3) Heating patterns in cylindrical structures were studied with inhomogeneous models of limbs. Arm and thigh models consisting of fat, bone, and muscle material were heated with Clini-Therm L, M, and MS applicators at 915 MHz. In addition to the geometric effect, the results indicated that placing the applicators with E field parallel to the long axis of cylindrical structures can minimize required power, produce less heating of fats and reduce stray radiation. In conclusion, to apply penetrating microwave or other RF fields for tissue heating, one must simulate the clinical exposure conditions as closely as possible to obtain useful heating patterns.

Evaluation Studies as Topic↗

PubMed1992

Glucocorticoid stimulates hepatitis B viral gene expression in cultured human hepatoma cells.

Glucocorticoids have been shown to influence the severity of hepatitis B virus-related chronic hepatitis in human. However, very little is known about the effects of glucocorticoids on hepatitis B virus replication in vitro. In this report, we used a well-differentiated human hepatoma cell line, Hep3B, transfected with hepatitis B virus complementary DNA as a model to show that a glucocorticoid analog, dexamethasone, can directly stimulate the production of HBsAg and HBeAg. Elevation of 3.5-kb pregenomic RNA and all other viral RNAs in the transfected Hep3B cells after dexamethasone treatment supports the hypothesis that glucocorticoids directly stimulate hepatitis B virus gene expression in vitro. The concentration of dexamethasone for its half-maximal stimulatory activity toward HBsAg, HBeAg and all viral transcripts was approximately 10(-8) mol/L, close to the affinity of glucocorticoid receptors to [3H]-triamcinolone acetonide in Hep3B cells (approximately 10(-8) mol/L). Specific glucocorticoid antagonist RU38486 completely blocked dexamethasone-induced HBV gene expression, suggesting that the stimulatory effect of dexamethasone was mediated through specific glucocorticoid receptors.

Carcinoma, Hepatocellular↗

PubMed1992

MRI manifestations of peritoneal carcinomatosis.

Three cases of proved peritoneal carcinomatosis were examined by magnetic resonance imaging (MRI). Air was used to distend the entire gastrointestinal tract via an antegrade method. The findings included seedings along the small intestine, transverse and sigmoid colon, stellate pattern in the mesentery, plaque-like and bulky tumor masses in the mesentery and greater omentum, and focal thickenings along the right subdiaphragmatic parietal peritoneum. Stenosis caused by tumor encasement at the duodenojejunal junction and ileocolic anastomosis were first detected by MRI and later confirmed by barium studies. Ascites was present in all cases. One case showed ascites located only along the left paracolic gutter. This report shows that MRI is also able to demonstrate peritoneal carcinomatosis by using air as a gastrointestinal contrast medium.

Adenoma, Bile Duct↗

PubMed1992

Microskin grafting of rabbit skin wounds with Biobrane overlay.

Biobrane was used to overlay micrografts and the wound using the microskin grafting technique with an expansion ratio of 10:1 in 16 rabbits. The rabbits were divided randomly into four groups, with four rabbits in each group, for evaluating the wound conditions on days 7, 10, 12 and 14. Histological examination of the removed Biobrane showed a variable degree of entrapment of inflammatory cells within the nylon fabric. Biobrane adhered well to the wounds although many wrinkles containing fluid accumulations were noted on day 7. By 10, 12 and 14 days all the wounds become dry and their Biobrane adhered completely. Histological examination of the grafted wound on day 7 showed active proliferation and spread of micrografts. In the later groups, the neoepidermis increased in thickness and differentiated into skin with a normal texture. On day 10, the wounds were almost completely resurfaced with neoepithelium. The growth of these grafts progressed smoothly as the adherent Biobrane was kept on the wound for 12 or 14 days. In these animal studies, the overlain Biobrane provided favourable conditions for the successful growth of micrografts.

Animals↗

PubMed1992

Microskin autograft with pigskin xenograft overlay: a preliminary report of studies on patients.

Split-thickness pigskin graft (STPSG) was used to replace allograft skin for microskin grafting in 16 patients, nine of whom were burn patients, five suffered from traumatic defects and two from diabetic ulcers. The expansion ratios used in these patients ranged from 8:1 to 12:1. The STPSG preparation described was found to be safe for clinical application. The autogenous donor skin was excised from the inguinal area, and the donor site was primarily closed. There were no instances of donor site morbidity. The majority of the STPSG overlays adhered to the wound firmly. Histological examination showed that the microskin grafts proliferated actively immediately beneath the STPSG overlay. The time for the wound to be fully resurfaced varied from 13 to 21 days depending on the expansion ratio employed. There were only two episodes of pseudomonas infection and no further grafting was required in any of the patients. In this study the pigskin xenograft was found to provide a suitable environment for the epithelialization of microskin autografts. When allograft is not available, this is an alternative way of ensuring successful microskin grafting.

Adolescent↗

PubMed1992

The adipofascial turnover flap for elbow coverage.

Closure of soft tissue defects in the vicinity of the elbow with exposed bone or joint remains a difficult problem. Local adipofascial turnover flaps covered by a skin graft were successfully used to reconstruct two elbow defects. The flap's base was placed 1.5 to 2.0 cm from the wound edge. The flap-to-base area ratio, which is an important index of flap survival, in addition to the traditional length-to-width ratio were 3.25 and 3.3, respectively. The undermined skin of the flap donor site was preserved rather than discarded as in the conventional deepithelialized turnover flap. The primary benefits of this flap are that it is an easy and rapid one-stage procedure, it requires limited immobilization of the involved joint, and it leaves an inconspicuous donor site scar. The motion of the elbow joint was not impeded because the adiposal component of the flap faced the exposed vital structures. The padding is not thick, but is sufficient to cover and protect the elbow. The flap is especially indicated for small- to medium-sized, complicated elbow wounds.

Accidents, Traffic↗

PubMed1992

Clinical application of the adipofascial turnover flap in the leg and ankle.

In soft-tissue defects with bone exposure over the leg and ankle, it is often impossible to achieve wound closure by a simple skin graft. In this article, we present a simple and effective way to reconstruct complicated skin defects on the pretibial region (four patients), the ankle (three patients), the distal fibula (one patient), and the medial aspect of the leg (one patient). Dissection of the local adipofascial turnover flap is quite easy and quick, requires less time, and involves less risk to the patient. It can be completed as a single-stage procedure, and no muscle function or major artery must be expended. Although there are numerous options for reconstruction of soft-tissue defects of the leg and ankle, the nonbulky adipofascial turnover flap appears particularly indicated for small- to medium-sized defects. The contours of the recipient and donor sites are acceptable aesthetically. Adequate flap-to-base area ratio and length-to-width ratio, tension-free insetting of the flap, and noncompression dressing are essential for the flap's survival.

Adolescent↗

PubMed1992

CRF increases protein phosphorylation and enhances retention performance in rats.

This study examines the roles of PKC and protein phosphorylation in the retention performance of a passive avoidance learning (PAL) task in rats. Results revealed that H7 injected into the dentate gyrus (DG) of the hippocampus impaired retention in a dose-dependent manner. Corticotropin-releasing factor (CRF) injected into the DG improved retention and this facilitation was antagonized by H7 pretreatment. CRF increased phosphorylation of five proteins, whereas H7 decreased phosphorylation in three of these proteins in both the cytosol and the membrane fractions of hippocampus. These effects were shown not to be associated with stress. These results demonstrate that CRF increased protein phosphorylation associated with enhanced retention of PAL task in rats.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1992

An eccentrically coated asymmetric antenna applicator for intracavitary hyperthermia treatment of cancer.

In this paper a model based on transmission line theory is used to predict the behavior of an eccentrically coated asymmetric antenna applicator for use in intracavitary hyperthermia. Theoretical results for the heating rate (HR) of the applicators are compared to experimental results. The experimental results were obtained at City of Hope National Medical Center using four different 915-MHz applicators, each with a different antenna size and eccentricity of the coating. A parameter delta is defined where delta << 1.0 is a thin wire approximation; delta is primarily a function of the eccentricity of the coating, the antenna diameter, and the coating diameter. It is found that when delta approximately less than 0.5, the theoretical model works well. In particular, it predicts the directivity due to the eccentricity of the coating. However, as this eccentricity is increased or as the antenna diameter is increased (delta approximately greater than 0.6), the model no longer accurately predicts directivity. Thus, the model that can be used to predict the HR profiles for an eccentrically coated asymmetric antenna only when delta approximately less than 0.5.

Computer Simulation↗

PubMed1992

Pneumatosis cystoides intestinalis arising in jejunal diverticular disease: report of a case and a suggestion to its pathogenesis.

The occurrence of pneumatosis cystoides intestinalis (PCI) in the gastrointestinal tract is rare. Among the cases already documented in the English language literature, the association of PCI with jejunal diverticulosis has only been mentioned once or twice. We herein report a case of a 63-year-old woman who had both entities concurrently in a segment of the jejunum. What is important to note is the relationship of PCI to the diverticulosis and its possible pathogenesis. Through histological examination and review of related articles, we are convinced that a mechanical theory plays a pivotal role when both diseases occur in the same segment of intestine and are compounded by obstruction or impaired peristalsis. This finding, when properly applied to PCI in other settings, helps to resolve the pathogenesis of PCI and other related gas-filled cysts.

Diverticulum↗