Biomedical subjects
Publications and source records attributed to Y Chao.
Complication of endoscopic variceal injection sclerotherapy for esophageal variceal hemorrhage is not unusual. However, sclerotherapy complicated panophthalmitis was never reported before. We report such an unusual complication and discuss its possible mechanism and treatment.
The repair of defects of articular cartilage has continued to be a difficult problem. This article provided a collective review from literature pertaining to the advances gained in the repair of cartilaginous defects. In the spontaneous repair, if the defect of the cartilage was less than 3 mm, might result in complete or partial repair, but in those the diameter was more than 3 mm, the defect could not be repaired by normal cartilage. Although the cartilaginous autograft could give good result, but it could not be widely applied because short of supply of the autogenous cartilage. Cartilagious allograft could not be taken to repair cartilaginous defect because of reaction from tissue rejection. The transplantation of periosteal or perichondral graft had been tried but was eventually abandoned because of poor long-term result. The transplantation of free chondrocytes might be a method of hope. In general, transplantation of free chondrocytes into the cartilaginous defect will be lost. The supply of autogenous chondrocytes was very limited, and the heterogenous chondrocytes would inflict immunoreaction after being transplanted. In late of 1980, a new concept of tissue engineering was proposed. The problem that a scaffold of appropriate material which could hold the free chondrocytes in place from being lost might undergo proliferation and differentiation into new cartilage was far from being solved. Although tissue engineering still had various problems needed further investigation, but it will probably be the main direction of development in this field.
This study was aimed at the feasibility of using HA-coated titanium endosseous implants as orthodontic anchorage. These implants installed in dog's mandibles were loaded with the orthodontic force of 150 g for 3 months. The stability of the implant and the peri-implant neck tissue were investigated with radiograph and index evaluation. The findings demonstrated that no implant was mobile or loose or dislocated. The soft tissue around the cervical part of the implants had a slight inflammation because of bad oral hygiene and the stimulation of residual food attached to the stainless string. However, no resorption of marginal alveolor bone was found under sustained orthodontic force. The above results suggest that the HA-coated titianium implant can be used as anchorage for short-term orthodontic treatment.
To develop a new ceramic material that can be machined and infiltrated with glass, a porous alumina blank sintered at 1350 degrees C was made of high purity, super fine alpha-alumina and then infiltrated with glass in this study. The density, bending strength and fracture toughness of the partially sintered alumina and alumina-glass composite were determined. The results indicated that the porous alumina density was 2.12 g/cm3, the three point bending strength 102 MPa, the fracture toughness 1.61 MPam1/2; that the alumina-glass composite density was 3.85 g/cm3, the three point bending strength 385 MPa, and the fracture toughness 4.05 MPam1/2. By SEM and EDXA analysis, lanthanum boroslicate glass was completely infiltrated into the 3 mm thick porous alumina blank for 6 h at 1150 degrees C. These suggest that the new developed alumina blank is suited for clinical use.
OBJECTIVE: To study the optimal level of PEEP at early stage of ARDS. METHOD: The parameters of hemodynamics, lung mechanics, and gas exchange were compared at different levels of PEEP, including maximal static compliance PEEP, point-inflection PEEP, 3 cmH2O higher or lower than point-inflection PEEP, and zero end-expiratory pressure. RESULTS: Point-inflection PEEP (6.8 +/- 1.4 cmH2O) was significantly lower than maximal static compliance PEEP (9.3 +/- 1.4 cmH2O), P < 0.01. The hemodynamic parameters were not significantly different in point-inflection PEEP compared with 0cmH2O-PEEP (P > 0.05), but oxygenation index (PaO2/FiO2) and lung mechanics (static compliance and airway resistance) were improved significantly at point-inflection PEEP (P < 0.01). At maximal static compliance PEEP or 3 cmH2O higher than point-inflection PEEP, the hemodynamic parameters and PaO2/FiO2 were not different from those at point-inflection PEEP (P > 0.05). The pulmonary vascular resistance index (PVRI) was significantly higher (P < 0.05) and the mean airway pressure and peak inspiratory pressure increased significantly (P < 0.01). CONCLUSION: In the treatment of early ARDS, the PEEP needed may be lower than the "optimal PEEP" determined by obtaining the maximal static compliance. The application of point-inflection PEEP determined at inspiratory static pressure-volume curve was appropriate as the best PEEP.
BACKGROUND: Colonic complications in patients with acute pancreatitis may be very severe and have rarely been analyzed in Chinese patients. METHODS: We retrospectively evaluated 1,637 patients with acute pancreatitis who were admitted to the Veterans General Hospital-Taipei from January 1986 to December 1995 in order to identify those with severe colonic complications. The clinical, radiologic and pathologic features and surgical findings in these patients are reviewed. RESULTS: Eight of 1,637 patients with acute pancreatitis had severe colonic complications. Six of them were diagnosed between two and eight weeks after the onset of clinical pancreatitis. All had a Ranson's score of at least 3. Four patients, including one with hematochezia, had a strong positive reaction for occult blood in stool specimens. Computed tomography (CT) revealed necrotizing pancreatitis and colonic wall swelling in all eight patients. Colonic involvement was discovered by CT in two patients prior to surgery, one with colocutancous fistula and the other with colonic perforation. The other six patients were found to have colonic involvement incidentally at the time of laparotomy. All of the colonic involvements were located near the splenic flexure. In addition to necrosectomy, three patients underwent segmental hemicolectomy and the remaining five patients had simple closure of the perforation. Diverting loop ileostomy or colostomy was also carried out in all patients. Three patients (34%) died of overwhelming sepsis superimposed on the subsequent multiple organ failure between 44 and 122 days after the onset of pancreatitis. CONCLUSIONS: Severe colonic complications of acute pancreatitis are rare. Although preoperative diagnosis is difficult, CT may be helpful to make an early diagnosis. These complications should be suspected in patients with severe acute pancreatitis when acute lower gastrointestinal hemorrhage or positive stool occult blood is found two to eight weeks after the onset of pancreatitis or when CT reveals necrotizing pancreatitis and colonic wall swelling; this will allow early surgical intervention.
BACKGROUND/AIMS: To realize the roles of peripheral vasodilatation and atrial natriuretic peptide in the formation of cirrhotic ascites, the effects of long-term administration of octreotide on carbon tetrachloride-induced cirrhotic rats were evaluated. METHODS: Urine sodium excretion, hemodynamics, plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations were compared between cirrhotic and control rats (protocol 1); and between octreotide- (65 micrograms/kg, twice daily for 10 days, subcutaneously) and placebo-treated (5% dextrose) cirrhotic rats (protocol 2). In an in vitro experiment, right atrial tissue of cirrhotic rats was incubated with different concentrations of octreotide to evaluate the release of atrial natriuretic peptide (protocol 3). RESULTS: Cirrhotic rats had significantly lower urine sodium excretion and systemic vascular resistance, and significantly higher plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations than control rats. Compared with placebo-treated cirrhotic rats, octreotide caused increased urine sodium excretion (-10 +/- 4% vs. 13 +/- 8% from baseline values, p < 0.05) and systemic vascular resistance (2.6 +/- 0.1 vs. 3.3 +/- 0.3 mmHg.min.100 g.ml-1, p < 0.05); and decreased plasma atrial natriuretic peptide levels (166.7 +/- 24.8 vs. 234.0 +/- 19.2 pg/ ml, p < 0.05), renin activities (2.45 +/- 0.49 vs. 4.36 +/- 0.53 ng.ml-1.h-1, p < 0.01) and aldosterone concentrations (290.2 +/- 40.0 vs. 483.3 +/- 82.6 pg/ml, p < 0.05). In the in vitro experiment, right atrial release of atrial natriuretic peptide of cirrhotic rats was not significantly changed when incubated with different concentrations of octreotide. CONCLUSIONS: Octreotide ameliorates renal sodium retention and suppresses plasma levels of atrial natriuretic peptide of ascitic cirrhotic rats with a novel mechanism via, at least partly, the modification of peripheral vascular resistance.
This is a report of a phase II study of megestrol acetate (160 mg/day, orally) in the treatment of hepatocellular carcinoma (HCC). Forty-six patients with advanced HCC were studied and tumour response, changes in appetite, bodyweight, a feeling of well-being, survival and toxicity were evaluated. Thirty-two patients were able to be evaluated for response; there were no complete responders or partial responders. Twelve patients (38%) had stable disease and seven of these patients had a minor response with a median size reduction in the tumour of 18%. Twenty patients (62%) had progressive disease. Five of 24 (21%) patients had a median reduction in alpha-fetoprotein levels of 59 ng/mL. The overall median survival was 4 months (range 1 week to 27 months). Twenty of 32 (62%) patients had an increased appetite and feeling of well-being. Fourteen of 22 (64%) patients had a median lean bodyweight gain of 5 kg (range 1-14 kg). Toxicities were minimal. Tests for glucocorticoid receptors were performed in 10 patients. Four of five patients who were positive for glucocorticoid receptors in the tumour had a stable disease and all five patients who were negative for glucocorticoid receptors had progressive disease. Megestrol acetate had no significant effect on the tumour in HCC patients. However, megestrol acetate is useful in the palliative management of HCC patients, with improvements in appetite, bodyweight and a feeling of well-being with minimal side effects. Some patients had stable disease, a minor reduction of tumour size and a prolonged survival after megestrol acetate treatment and this response may be related to the presence of glucocorticoid receptors in the HCC tumour.
This experiment studied the influence of porcelain thickness and non-uniformity on porcelain crack in implant-supported metal-porcelain fixed bridge. The result indicated that porcelain crack began to appear when the body porcelain powder was 3-5 mm in thickness; more cracks took place when the powder thickness increased by 1 mm to 2 mm on the axial surface in the axial direction; cracks became serious when the thickness suddenly changed to zero; and connectors were liable to cracks. Therefore, in designing and fabrication, one should avoid and sudden change in the shapes of the connector and the porcelain on it, any sudden change in the thickness of porcelain and a thickness of porcelain powder not less than 3.5 mm. Other-wise, it is neccessary to use internal crown between metal base and abutment to meet the demands.
In order to explore the infiltration condition of GI- I slip casting aluminous ceramic core glass material to aluminous ceramic substratum and provide reference for clinical use, the linear change relationship between the minimal infiltration depth and infiltration time was determined by measuring the minimal depth of glass material infiltrated to aluminous ceramic substratum from one to six hours. The result showed: there is a high linear relationship between the minimal infiltration depth for GI- I infiltration glass and the infiltration time. For clinical use, the minimal infiltration time for GI- I slip casting aluminous ceramic core at least 2.5 hrs and 5 hrs for bridge framework.
The stress distributions of the modified bar-clip implant-borne overdenture in the edentulous mandible were performed under punching loads with both porcelain and resin chosen as the restorative materials by means of three-dimensional anisotropic finite element method. The purpose of this study was to investigate the patterns of stress distributions and to compare the effect of different restorative materials on the stress distributions under punching loads. The results showed that the value of stress peaks in implants with porcelain restorations seemed higher than those with resin restorations. On the contrary, in the bone-implant interface had little difference, except a comparative uniform stress distribution found in resin restorations. It implies that resin restoration produces a cushioning effect on reducing the stress peaks in implants themselves under punching loads. Both porcelain and resin restorations can be chosen as the restorative materials because of a little influence on the stress peaks in bone-implant interface under punching loads.
An experiment on fitness of retainers of one-piece casting frameworks was performed between two non-noble metals and among three of abutment positions fixture implant with a coordinate measuring machine for three-dimensional analysis. The results showed that there was no statistically significant differences in retainer fitness between the two metals, and among the three fixture abutment positions. However, all retainer displayed shrinkage in three dimensions, and the retainer shrinkage on the cervical surface were more than on the occlusal surface. The fitness of retainers of one-piece casting frameworks would be improved if used in multi-unit implant fixed denture.
The setting time, the setting expansion ratio and the compatibility with impression materials of the HX-I refractory die material were determined. The results showed: the setting time was 11 +/- 3 min: the setting expansion ratio was 0.23%; the compatibility with impression materials was excellent between HX-I die material and agar or silicone rubber respectively, but the compatibility was bad between HX-I die material and alginate. These properties of HX-I die material were close to the ones of Lamina die material.
GL331 is a semisynthetic topoisomerase II inhibitor derived from a plant toxin podophyllotoxin. In 72-h exposure assays, LD50 values of GL331 range from 0.5 to 2 microM, which are three- to ten-fold lower than those of its homologous compound etoposide (VP-16), depending on different cancer cell lines including nasopharyngeal, hepatocellular, gastric, cervical and colon cancer types. Apoptotic DNA ladders could be detected when cancer cells were treated with GL331 for 24 h even if the Bcl-2 and Bax protein levels were not altered during the period. Besides acting as topoisomerase II inhibitors, both GL331 and VP-16 decrease the cellular protein tyrosine kinase (PTK) activities in cancer cells. The activities of protein tyrosine phosphatase (PTP) are significantly increased after GL331 treatment but are not affected by VP-16. GL331-induced internucleosomal cleavage can be efficiently prevented by two inhibitors of PTP, sodium orthovanadate and zinc chloride, but not by okadaic acid, which inhibits serine/threonine phosphatase activity. These results indicate that GL331 may induce apoptotic cell death, and that activation of protein tyrosine phosphatases may be involved in this process.
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BACKGROUND: Hepatocellular carcinoma (HCC) is a male predominant disease and may be an androgen-dependent or androgen-responsive tumor. This Phase 11 study was designed to investigate the clinical activity and toxicity of flutamide in the treatment of patients with advanced HCC. METHODS: Thirty-two patients with measurable advanced HCC were studied. Flutamide, 750 mg per day, was administered orally for 8 weeks. Ten patients died before repeat tumor measurements could be performed. RESULTS: Twenty-two patients were evaluable for response and toxicities. There were no complete responses nor partial responses. Nine of 22 patients (41%) had stable disease and 13 patients (59%) had progressive disease. Serum alpha-fetoprotein was reduced in three patients. The median survival was 10 weeks (range, one to 35 weeks). Toxicities were minimal and tolerable. CONCLUSIONS: Flutamide is not effective in the treatment of advanced HCC. Clinically, HCC may not be an androgen-responsive tumor. Other new methods of treatment of HCC warrants future clinical investigations.
AIMS/METHODS: Frozen sera obtained from 70 patients (35 with hepatocellular carcinoma and 35 with benign chronic liver disease) with serum alpha-fetoprotein > 20 ng/ml were studied to evaluate the diagnostic indices of lentil lectin affinity of alpha-fetoprotein in detecting hepatocellular carcinoma. RESULTS: The proportion of alpha-fetoprotein-L3 was significantly higher in patients with hepatocellular carcinoma than in those with benign chronic liver disease (41.0 +/- 33.6% vs. 16.4 +/- 15.3%, p < 0.001). This difference led to a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 57, 89, 83, 67 and 73%, respectively, in detecting hepatocellular carcinoma using the proportion of alpha-fetoprotein-L3 > 35% as a parameter. Within a 1-year period, 1500 high-risk persons were collaborating, leading to 22 cases with serum total alpha-fetoprotein > 20 ng/ml. These 22 cases included six pregnant women. The parameter, alpha-fetoprotein-L3 > 35% was used along with sonography to detect hepatocellular carcinoma for the remaining 16 cases. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 75, 83, 60, 91 and 81%, respectively, by the proportion of alpha-fetoprotein-L3 > 35%; and 100, 92, 80, 100 and 94%, respectively, by sonography. CONCLUSIONS: Lentil lectin affinity of alpha-fetoprotein provides a moderately high sensitivity and a high specificity in the detection of hepatocellular carcinoma for persons with high alpha-fetoprotein levels. It may be a useful adjuvant tool of sonography and total alpha-fetoprotein level in a mass survey of hepatocellular carcinoma for a high-risk population.