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Biomedical subjects

S H Chao

Publications and source records attributed to S H Chao.

At least 37 records · Page 2Linked to original sources

Renal transplantation at Allegheny General Hospital with special reference to the use of extreme-age cadaveric donors.

We report our experience with 25 living-donor and 427 cadaveric-donor kidneys followed for over 6 years. Patient survival exceeds 90% at 5 years for all recipients. Overall one-year and 5-year graft survival rates were 82.7% and 65.5%, respectively. Approximately one-third of CAD were of extreme age (eg, < or = 10 and > or = 60 years old). One-year and 5-year GS rates of this group were 72.2% and 54.8%, respectively. Kidneys from elderly donors probably should be given to age-matched recipients. Infant en bloc kidneys had good GS. They also adapted well their growth and function to adult recipients and should be used more frequently to alleviate the organ shortage problem. HLA mismatches, transplant PRA level, original kidney disease, and immunosuppressive regimens significantly affected the GS. Race, sex, cytomegaloviral antibody states, unacceptable antigens, length of pretransplant dialysis, and CAD cold ischemic time had no significant effect on GS.

Adolescent↗

In vivo antithrombotic effect of triflavin, an Arg-Gly-Asp containing peptide on platelet plug formation in mesenteric microvessels of mice.

Triflavin, an Arg-Gly-Asp-containing snake venom peptide, inhibits platelet aggregation through the blockade of fibrinogen binding to the activated platelets. In this study, platelet thrombus formation was induced by irradiation of the mesenteric venules with filtered light in mice pretreated intravenously with fluorescein sodium. Electron microscopy reveals moderately damaged endothelial cells, as well as aggregates consisting almost exclusively of platelets with pseudopod formation, and degranulated appearance. Triflavin (10-20 micrograms/g) significantly prolonged the lag period of inducing platelet plug formation in mesenteric venules when it was intravenously infused. Triflavin (20 micrograms/g) prolonged the occlusion time about 2-fold (from control 112 +/- 23 to 240 +/- 47 s). Furthermore, PGE1 briefly prolonged the occlusion time about 1.5-fold (from 105 +/- 21 to 168 +/- 20 s) when it was given by continuous infusion (40 micrograms/kg/min). On the other hand, triflavin was also effective in reducing the mortality of ADP-induced acute pulmonary thromboembolism in mice when administered intravenously at dose of 2-4 micrograms/g. Heparin (1.5 U/g) and indomethacin (200 micrograms/g) had no significant effect in prolonging the occlusion time or in reducing ADP-induced pulmonary embolism in mice. Therefore, triflavin is an effective antithrombotic agent in preventing the thromboembolism in these two in vivo models.

Acute Disease↗

Epilogue: health care reform and productivity.

Only a health care system that balances the best interests of consumers with those of employers and government payers will ultimately provide quality care at manageable costs. These need not be opposing interests.

Consumer Advocacy↗

Revision of dysfunctional Tenckhoff catheters by laparoscopic technique in continuous ambulatory peritoneal dialysis patients.

A laparoscopic technique was used to rescue dysfunctional Tenckhoff catheters in five continuous ambulatory peritoneal dialysis (CAPD) patients. This method proved to be effective in recovering the function of the catheters, whose malfunction was found to be due to catheter entrapment or endoluminal tamponing by the omentum. The videoscope-assisted laparoscopic technique provides access and allows identification and eradication of the specific etiology leading to catheter drainage failure. It also provides an alternative for treating patients with a dysfunctional Tenckhoff catheter. This method avoids the need to remove the original catheter or to reimplant a new catheter.

Adult↗

Laparoscopic-guided gastrostomy.

Gastrostomy is commonly performed in patients who have esophageal stenosis or difficulty in swallowing. The fact that most patients who require a gastrostoma are usually malnourished or debilitated urges surgeons to seek a convenient and reliable method for performing the operation. Percutaneous endoscopic gastrostomy (PEG) was introduced into clinical practice and recommended as the procedure of choice in the 1980s. However, PEG was not indicated and only traditional open gastrostomy was considered for those who had obstruction in their oroesophageal canal. We describe a technique for placement of a gastrostomy tube under laparoscopic control. The technique is easily mastered, requires equipment routinely used in laparoscopic control. The technique is easily mastered, requires equipment routinely used in laparoscopic surgery, and can be used by surgeons untrained in gastroendoscopy. When performed properly, the method is accurate, economic and reliable.

Gastrostomy↗

Entrapment of cultured pancreas islets in three-dimensional collagen matrices.

In vitro culture of islets of Langerhans decreases their immunogenicity, presumably by eliminating passenger leukocytes and other Ia+ presenting cells within the islets. Islets cultivated in petri dishes either at 37 degrees C or at 25 degrees C gradually disintegrate during culture in a time-dependent manner which is related to the free-floating condition of the islets. Also, a fraction of the islets disperse as single cells and beta-cell aggregates or adhere to the bottom of the culture dishes. Thus, the retrieval rate of transplantable islets is dampened due to their disintegration and spontaneous dispersion in conventional petri dish cultures. Entrapment of freshly harvested islets of Langerhans in a three-dimensional collagen matrix was studied as an alternative method for islet cultivation. The contraction of collagen fibrils during in vitro culture counteracts the dispersion of islets and helps in maintaining their integrity while in culture. It was observed that the entrapped islets maintain satisfactory morphology, viability, and capability of glucose-dependent insulin secretion for over 2 wk. The oxygen consumption rate and glucose metabolism of these islets was not deranged when entrapped in collagen. Also, the retrieval of islets is easier and more efficient than that observed in conventional culture systems. Our results indicate that culture of islets in three-dimensional collagen gels can potentially develop into an ideal system applicable to clinical transplantation of cultured islets or beta-cell aggregates.

Animals↗

Serum interleukin-2 and soluble interleukin-2 receptor in renal transplant recipients.

Interleukin-2 (IL-2) and soluble interleukin-2 receptor (sIL-2R), released during T-lymphocyte activation, were measured in serial samples of serum from 32 patients with renal allografts and other uremic patients. Patients undergoing chronic hemodialysis had elevated sIL-2R levels (1,801.93 +/- 753.23 U/mL) which dropped after stable renal transplantation (822 +/- 438 u/mL). However, these values were higher than those of a normal control group (397.3 +/- 84.5 u/mL, p < 0.01). Marked elevation of sIL-2R (1,503.78 +/- 640 u/mL) was noted in patients with acute rejection episodes compared to those in a stable allograft condition (p < 0.02) and those with cyclosporine nephrotoxicity (793.2 +/- 245.2 u/mL, p < 0.01), but returned to a stable level after successful anti-rejection treatment (745.91 +/- 345.8 u/mL, p < 0.01). Acute tubular necrosis and infection also showed a comparable rise in the sIL-2R level. The increase in sIL-2R with rejection was found one to four days earlier than the clinical diagnosis of acute rejection. There was a marked rise in the serum IL-2 level of uremic and post-transplant patients when compared to normal subjects (34.76 +/- 32.16 u/mL and 9.3 +/- 12.7 u/mL vs 4.38 +/- 3.38 u/mL, p < 0.001), but no significant differences were found between the IL-2 level of patients with acute rejection and cyclosporine nephrotoxicity or acute tubular necrosis (3.74 +/- 4.51 u/mL, 1.57 +/- 1.25 u/mL and 6.73 +/- 6.3 u/mL, p > 0.05). The diagnostic value of sIL-2R assay was more meaningful than that of IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

An analysis of traffic injuries in Taiwan in relation to alcohol use and economic loss.

Breath alcohol analysis of 449 patients with motor vehicle injuries attending the emergency department of a Taiwan urban general hospital during a 10-week period showed that 19.2 per cent had breath alcohol concentration (BAC greater than 0.002 per cent and 8.5 per cent greater than or equal to 0.05 per cent). Injured males were more likely to have BAC greater than or equal to 0.05 per cent than women (11 per cent vs 0 per cent). Injuries resulting from alcohol-associated collisions were about 6.7 times more likely to occur between 1800 and 0600 than at other time periods. A telephone survey after hospital discharge showed that the risk factors of alcohol use, speed at time of collision and type and site of collision were significantly associated with degree of economic loss resulting from the accidents. Logistic regression analysis showed that the odds of high economic loss associated with BAC greater than 0.002 per cent were three times greater than for persons in whom no alcohol was detected. This is the first study in Taiwan to use breath alcohol analysis in assessing the effect of alcohol consumption on motor vehicle injuries. The results show that alcohol use is an important cause of motor vehicle injuries. Preventive measures such as strict legal control of drunk driving and limitation of the hours that drinking places can stay open at night are recommended to reduce the damage caused by this severe public health problem.

Accidents, Traffic↗

Activation of troponin C by Cd2+ and Pb2+.

Certain heavy metal actions such as Cd2+ and Pb2+ mimic Ca2+ effectively in stimulating calmodulin (CaM). We now show that these cations also activate skeletal muscle troponin C (TnC), a Ca2(+)-binding protein highly homologous to CaM. Like Ca2+, these cations allow TnC to alter its electrophoretic mobility on polyacrylamide gels, and to bind to phenyl-Sepharose. Moreover, they activate TnC to stimulate myofibrillar ATPase. When TnC was removed from the skeletal myofibrils by treatment with trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CDTA), the ATPase activity was no longer stimulated by the cations. However, after reconstitution of CDTA-treated skeletal myofibril with TnC, the response of ATPase to Ca2+, Cd2+ or Pb2+ was restored. These findings suggest that the activation of myofibrillar ATPase by Cd2+ and Pb2+ is mediated through TnC. The ability of the heavy metals to stimulate TnC-supported ATPase activity correlated quite well with the ability to increase the extent of the myofibrillar superprecipitation. The activation of TnC by Cd2+ or Pb2+ could constitute a possible molecular basis for their toxicity.

Adenosine Triphosphatases↗

A technique using V-shaped transmural suture fixation in percutaneous endoscopic gastrostomy.

A new method of percutaneous endoscopic gastrostomy (PEG) using V-shaped transmural suture fixation was performed on 2 patients with advanced carcinoma. This method secures the gastrostoma in a way superior to the conventional technique. It facilitates exchange of the catheter and avoids potential morbidity caused by peritoneal leakage even when tube feeding has been initiated in the early post-insertion stage. Inadvertent complications of hematoma formation and necrotizing fasciitis can also be prevented.

Aged↗

Aortomesenteric bypass using autogenous saphenous vein graft for superior mensenteric artery aneurysm: report of a case.

We report a 62-year-old man who had symptoms of abdominal angina and was diagnosed preoperatively with a superior mesenteric artery (SMA) aneurysm. The findings of the CT scan and angiography revealed a 3 X 4 cm saccular aneurysm at the proximal site of the SMA. During abdominal exploration, a weak pulsation of the SMA branches distal to the aneurysm was felt. The aneurysmal cavity was full of old thrombi. Brisk retrograde bleeding from the orifices of the connecting collaterals was seen after removal of the thrombi. Our operative procedures included endoaneurysmorrhaphy, proximal ligation, and distal interruption of the aneurysm. Vascular reconstruction by an aortomesenteric bypass using a segment of autogenous saphenous vein graft was also done. After creating the vein graft bypass, the weak pulsation of the distal SMA branches became normalized. The patient enjoyed an uneventful postoperative course and did not complain of abdominal pain on clinical follow up. Four months later, he received an evaluation including angiography and CT scan, which confirmed that the vein graft was patent and without deformity.

Aneurysm↗