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Biomedical subjects

Y Chang

Publications and source records attributed to Y Chang.

At least 307 records · Page 17Linked to original sources
PubMed1989

[A new operation for the management of gastric varix bleeding].

Gastric varices is a special oriental type manifestation of gastroesophageal collaterals in portal hypertension patients. It has gained more attention in recent years following the popularity of endoscopy and sclerotherapy. Catastrophic bleeding from ruptures of gastric varices is a life threatening emergency. Gastric varices are generally located at the greater curvature side of the cardiofundic region. Neither a Sengstaken-Blakemore balloon tube nor a Linton balloon tube can stop the bleeding. This area is also beyond the field of sclerotherapy. Surgery is the only definite therapy. Devascularization procedures as described by Dr. Hassab sometimes fail to control active bleeding and also fail to adequately decongest the whole varices area. The radical resection procedures such as terminal esophagectomy, proximal gastrectomy or cardiectomy as proposed by Japanese groups interrupts the normal esophgo-gastric continuity and is also too invasive for a cirrhotic patient. In between, besides terminal esophago-proximal gastric devascularization and splenectomy, we use a TA-90 stapler to perform an oblique cardiofundectomy to resect en bloc the tortuous gastric varices area. From Nov. 1983 to May 1988, at the Veterans General Hospital-Taipei, 16 patients received this new operation to manage gastric varices bleeding. Ten of them were on an emergency basis and 6 were elective surgery. Only one patient in the emergency group died. All catastrophic bleeding in the emergency group was dramatically controlled and all other patients recovered rapidly. With a follow-up range from 6 months to 4.5 year and an average of 19 months, there was no recurrent bleeding and no hepatic encephalopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Esophageal and Gastric Varices↗
PubMed1988

IgA:IgM and IgA:IgA hybrid hybridomas secrete heteropolymeric immunoglobulins that are polyvalent and bispecific.

Polyvalent bispecific antibodies were secreted by hybrid hybridoma cells when both parental clones expressed a naturally polymerizing immunoglobulin. Hybrid hybridomas made from IgA lambda 2 anti-trinitrophenyl (TNP) and IgA kappa anti-phosphocholine (PC) parental cells secreted polymeric IgA antibodies that bound both TNP and PC. Some of the TNP binding was dissociated from the PC binding under conditions of mild reduction and alkylation suggesting that the bispecific polymeric IgA contained disulfide-linked parental monomers as well as bispecific hybrid monomers. Hybrid hybridomas constructed from IgA lambda 2 anti-TNP and IgM kappa anti-ox erythrocyte parental cells secreted bispecific, polymeric immunoglobulin that contained mu-, alpha-, kappa-, and lambda 2-chains. The mu and kappa-chains dissociated from the alpha- and lambda 2-chains under conditions of mild reduction and alkylation, indicating that both parental monomers had been incorporated into the same polymeric immunoglobulin to form a heteropolymeric antibody molecule. Heterologous pairing of alpha and mu heavy chains in monomers was not detected. Hybrid hybridomas constructed from IgA lambda 2 and IgG3 lambda 2 or IgA lambda 2 and IgG1 kappa parents co-secreted both parental immunoglobulins, but the antibodies secreted by these clones did not form heteropolymers or exhibit heterologous heavy chain pairing. These findings establish that polyvalent, bispecific, polymeric immunoglobulin molecules can be produced by hybrid hybridomas when both parents express a naturally polymerizing class of heavy chain but not when only one parent does. Hybrid hybridomas that produce heteropolymeric immunoglobulins are sources of high avidity bispecific antibodies that may find a number of basic and practical applications. The hybridoma cells that produce these antibodies may provide useful tools for investigating the in situ determinants of immunoglobulin chain association and the regulation of antibody assembly and secretion.

Animals↗
PubMed1988

Structure-activity relationship studies of hemicholinium (HC-3) congeners.

In a continuing investigation of structural requirements for hemicholinium-like activity (inhibition of neuromuscular transmission due to inhibition of uptake of choline into nerve terminals), some additional molecular modifications of hemicholinium ("HC-3"; structure 1) were made. The target compounds were prepared by standard one- or two-step sequences. Noncyclic acetal moieties in general permitted retention of pharmacological activity, as did concomitant replacement of the central biphenyl "spacer" by other bulky cyclic groupings and replacement of the oxazinium rings by piperidine or 4-methylpiperidine. However, these modifications generally produced compounds of a lower potency. Replacement of the biphenyl moiety of HC-3 with polyakylene chains permitted retention of a considerable degree of activity. In these target compounds, the two quaternary nitrogens can exist the same distance apart (approximately 14 A) as in the hemicholinium molecule. The ditertiary amino congener of a pharmacologically active bis-quaternary oxazinium compound was almost completely inactive. To date, only one tertiary amine has been found which displays a significant degree of hemicholinium-like activity.

Animals↗
PubMed1988

Smooth muscle cells can express cytokeratins of "simple" epithelium. Immunocytochemical and biochemical studies in vitro and in vivo.

Cytokeratins are a set of 19 proteins that together constitute the class of intermediate filament protein expressed by epithelial cells and tumors. Using a panel of 9 different monoclonal anti-cytokeratin antibodies, the authors have performed immunocytochemistry on methanol-fixed, frozen sections and methacarn-fixed, paraffin-embedded tissue of human myometrial specimens. Anomalous cytokeratin expression (ACE) by smooth muscle cells was found in all specimens. Immunoblots of this tissue confirmed the presence of cytokeratin 19, and possibly 8. In addition, immunocytochemical studies demonstrated ACE in human fetal tissues within the intestinal muscularis and the heart, especially in the region of the aortic outflow tract, and in 8 of 19 cases of leiomyosarcoma from adults. Indirect immunofluorescence studies were also performed on cells explanted from myometrial tissue; the overwhelming majority of cells derived from these cultures were smooth muscle cells as verified by expression of muscle actins, and a subpopulation of these cells was found to be cytokeratin-positive. ACE was confirmed in vitro by double labeling experiments demonstrating simultaneous expression of muscle actins and cytokeratins within the same cell. The significance of this smooth muscle cell ACE is unknown, but it may be a phenotypic marker of smooth muscle in a proliferative state. ACE could be a source of confusion in the immunocytochemical analysis of poorly differentiated malignancies if a complete panel of antibodies is not employed.

Cells, Cultured↗
PubMed1988

Emergency distal splenorenal shunt for medically uncontrollable variceal haemorrhage.

Emergency distal splenorenal shunt was prospectively carried out on 14 patients presenting with active bleeding from esophagogastric varices which was not controllable by medical treatment. Patients were composed of nine males and five females. Age ranged from 34 to 76 years with an average of 56.2. Underlying liver disease were cirrhosis of the liver in seven, cirrhosis and hepatocellular carcinoma (HCC) in five, primary biliary cirrhosis in one, and chronic hepatitis in one instance. Preoperatively, the Child's classification was A in one, B in five, and C in eight patient. Two patients underwent the original Warren shunt but the remaining 12 were treated by modified distal splenorenal shunts using Gore-Tex interposition. Three patients with Child's class C disease died within one month (operative mortality 21.4%). An oldest woman transiently had hepatic encephalopathy but recurrent variceal bleeding was not observed in any of the patients. Distal splenorenal shunt is a safe and reliable means in the treatment of medically intractable variceal hemorrhage.

Adult↗
PubMed1988

Prophylactic distal splenorenal shunt for child's class A and B patients at high risk of bleeding.

During recent 17 years, prophylactic distal splenorenal shunt was carried out on 29 patients. Patients were composed of 18 males and 11 females. Age ranged from 34 to 66 years with an average of 52.4. All patients had risky esophagogastric varices; varices larger than 5 mm in diameter and or varices with red color signs such as cherry red spots endoscopically. Underlying liver disease were cirrhosis of the liver in 27, chronic hepatitis in one, and idiopathic portal hypertension in one. Twenty-three patients were in Child's class A and six were in class B. Thirteen patients underwent the original Warren shunt but the remaining 16 had modified distal splenorenal shunts with expanded polytetrafluoroethylene interposition. Portal-azygos disconnection was routinely performed. One patients (3.4%) died of hepatic failure on the 6th postoperative day. Four patients (14.3%) developed hepatic encephalopathy of mild to moderate degree but no patients have suffered from variceal bleeding until now. The 5-, 10-, and 15-year survival rates were all 85.5 per cent. It is concluded that distal splenorenal shunt is a safe and reliable method to prevent variceal bleeding in a selected group of patients.

Adult↗