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Biomedical subjects

C W Yang

Publications and source records attributed to C W Yang.

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

Overexpression of transforming growth factor-beta 1 mRNA is associated with up-regulation of glomerular tenascin and laminin gene expression in nonobese diabetic mice.

Nonobese diabetic (NOD) mice spontaneously develop immune-mediated insulin-dependent diabetes mellitus and nephropathy, providing an opportunity to study the early molecular events in a model of diabetic glomerulosclerosis. The expression of several genes coding for growth factors and extracellular matrix was examined in microdissected glomeruli, by the use of reverse transcription-competitive polymerase chain reaction, in diabetic NOD mice (mean duration of diabetes, 28.5 +/- 7 days) and age-matched nondiabetic NOD mice with normal glucose tolerance. The levels of mRNA coding for transforming growth factor-beta 1, tenascin, and laminin B1 increased 1.9-, 2.0-, and 1.7-fold, respectively, whereas platelet-derived growth factor (PDGF)-B, alpha 1(IV) collagen, 72-kd collagenase, alpha-smooth muscle actin, and beta-actin mRNA remained stable in the diabetic mice. The kidney advanced glycosylation end-products levels increased 2.1-fold in the diabetic mice, and the diabetic glomeruli showed an accumulation of tenascin and laminin but not of type IV collagen by immunofluorescence microscopy. There was no increase in cell number per glomerulus after the onset of diabetes, a finding consistent with stable PDGF-B and alpha-smooth muscle actin mRNA levels. These findings provide evidence that increased glomerular transforming growth factor-beta 1, but not PDGF-B, mRNA is associated with the up-regulation of tenascin and laminin expression after advanced glycosylation endproduct accumulation, early after the onset of diabetes.

Animals↗
PubMed1995

Calcification in retroperitoneal non-Hodgkin lymphoma prior to treatment: a case report.

Calcification in malignant lymphoma before treatment is rare. Here we report a case of low grade non-Hodgkin lymphoma of sclerosing type presenting as a retroperitoneal calcified mass. The calcification was demonstrated with various imaging modalities, including conventional radiographs, sonography, computed tomography (CT) and magnetic resonance (MR) imaging. This case and other isolated reports show that radiographical examinations may, rarely, reveal calcification in lymphoma prior to treatment.

Adult↗
PubMed1995

Comparison of peritoneal catheter survival with fistula survival in hemodialysis.

OBJECTIVE: To compare continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) with regard to long-term maintenance of access. DESIGN: Retrospective study of a four- to six-year time period at one center. PATIENTS: One hundred and twenty-two CAPD patients between December 1988 and December 1992, and 172 HD patients between May 1986 and December 1992. MAIN OUTCOME MEASURE: Cumulative survival rate of peritoneal catheters and arteriovenous fistulas (AVF) was the main outcome measure. Variables affecting the survival rate including sex, age, presence or absence of diabetes, and type of AVF (autogenous or prosthetic graft) were assessed. The causes of peritoneal catheter failures were analyzed. RESULTS: The cumulative survival rate of all peritoneal catheters was significantly longer than the AVF survival rate (84% vs 74% at one year; 73% vs 61% at two years; and 63% vs 48% at three years) (p = 0.029). There were no differences in peritoneal catheter survival according to sex, age, or diabetes. Compared with AVF survival, peritoneal catheter survival was significantly longer in male (p = 0.0492), elderly (p = 0.0082), and diabetic (p = 0.0022) patients. Prosthetic graft and old age were risk factors for AVF survival. Of all peritoneal catheter failures, infectious complications were responsible for 75% (33/44) and mechanical complications for 25% (11/44). Peritonitis was the leading infectious complication (21/33) and outflow obstruction was the leading mechanical complication (9/11). CONCLUSION: In terms of long-term maintenance of access, CAPD is superior to HD, especially in the elderly or diabetics. Prevention and proper management of peritonitis may prolong the peritoneal catheter survival.

Adult↗
PubMed1995

Collagen and collagenase mRNAs in normal and sclerotic glomeruli: predictors of progression and response to therapy.

Progressive glomerulosclerosis is associated with decreasing kidney function, eventuating in end-stage renal failure. There are multiple components of the extracellular matrix, and the exact composition in various renal diseases is not known. Thus, we examined some of the major components of the extracellular matrix (ECM) in murine and human glomerular diseases. We studied matrix synthesis and degradation at the level of gene expression and ECM composition in the intact glomerulus. To determine whether the composition of sclerosis was similar among diseases, we examined a normal mouse strain and compared it with strains which spontaneously developed glomerulosclerosis. The baseline levels of matrix components varied between different mouse strains, and this level correlated with their propensity to develop glomerulosclerosis. In addition, when glomerulosclerosis was induced, the baseline ECM mRNA level predicted the subsequent outcome. We studied mice transgenic for bovine growth hormone, since they develop progressive glomerulosclerosis. Treatment with heparin substantially decreased the lesions without changes in type IV collagen mRNAs. However, there was an up-regulation of both the mRNA and enzyme activity for the 92 kD matrix metalloproteinase. In contrast, when these mice were treated with either angiotensin converting enzyme inhibitors or angiotensin II (Ang II) receptor antagonists, the glomerulosclerosis was accentuated histologically and the ECM synthetic and degradative mRNAs were elevated. These data suggest that the mRNA levels reflect response to therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Administration of AGEs in vivo induces genes implicated in diabetic glomerulosclerosis.

Administration of advanced glycosylation end products (AGEs), prepared on mouse albumin, to normal young adult mice, resulted in an increase in mean glomerular volume and up-regulation of laminin B1 and alpha 1 type IV collagen mRNAs measured by competitive PCR in single microdissected glomeruli. Both glomerular hypertrophy and overexpression of genes coding for extracellular matrix were abrogated when aminoguanidine, an inhibitor of AGE cross-linking, was added to the AGEs injections, suggesting that the glomerular response to AGEs was specific. The effects of AGEs administration in vivo are comparable to those occurring in the early stage of diabetic nephropathy, suggesting a participation of AGEs in these events.

Animals↗
PubMed1994

Advanced glycation end products up-regulate gene expression found in diabetic glomerular disease.

Several lines of evidence suggest that the excessive accumulation of extracellular matrix in the glomeruli of diabetic kidneys may be due to reactive intermediates forming between glucose and matrix proteins called advanced glycation end products (AGEs). Normal mice received AGE-modified mouse serum albumin i.p. for 4 weeks, and glomerular extracellular matrix, growth factor mRNA levels, and morphology were examined. We found that AGE induced an increase in glomerular extracellular matrix alpha 1(IV) collagen, laminin B1, and transforming growth factor beta 1 mRNA levels, as measured by competitive PCR, as well as glomerular hypertrophy. The AGE response was specific because the coadministration of an AGE inhibitor, aminoguanidine, reduced all these changes. We conclude that AGEs affected expression of genes implicated in diabetic kidney disease and may play a major role in nephropathy.

Actins↗
PubMed1994

Activation of a calcium- and pH-dependent phospholipase A2 by cyanide in PC12 cells.

Previous studies suggested that alterations in phospholipid composition of plasma membranes may contribute to neuronal injury associated with cyanide-induced histotoxic hypoxia. This prompted a study of the effects of KCN on phospholipase A2 (PLA2), an enzyme which catalyzes breakdown of membrane phospholipids. PLA2 activity was measured by quantitating the release of [3H]arachidonic acid ([3H]AA) from rat pheochromocytoma (PC12) cells. KCN produced a time (1-15 min)- and concentration (0.5-10 mM)-dependent release of [3H]AA from the cells. When cells were incubated in Ca(2+)-free buffer, KCN (5 mM) was still able to release [3H]AA. In cells loaded with BAPTA, an intracellular Ca2+ chelator, cyanide-induced release of [3H]AA was blocked, indicating that mobilization of intracellular Ca2+ can activate the enzyme. The PLA2 inhibitors dibucaine (50 microM) and mepacrine (50 microM) inhibited KCN-mediated [3H]AA release. Incubation of PC12 cells in an extracellular pH of 6.50 reduced the KCN effect, whereas incubation at pH 7.90 enhanced [3H]AA release. These data indicate that in PC12 cells KCN activates a Ca(2+)- and pH-dependent PLA2 which may contribute to cyanide-induced cell damage.

Animals↗
PubMed1994

Liver, renal and subcutaneous histopathology in PEPCK-bGH transgenic pigs.

Transgenic pigs were created that harboured a phosphoenolpyruvate carboxykinase-bovine growth hormone construct (PEPCK-bGH). Four founder animals and two transgenic offspring from one line were evaluated between 6 1/2 and 12 months of age. There was no evidence of severe hepatic or renal lesions in these pigs, which characterised transgenic PEPCK-bGH mice previously described. While glomerular and tubular lesions in kidney sections were not identified in the transgenic pigs, mesangial cell proliferation was observed in two transgenic offspring from a single line. Additionally, glomerular size was significantly increased in four of four puberal transgenic swine when compared to age- and sex-matched controls (28.30 +/- 4.1 vs. 14.2 +/- 2.7 x 10(5) microns 3; representing 3 transgenic lines, p < 0.05). Surprisingly, no mature adipocytes were observed in subcutaneous sections obtained in transgenic GH pigs. Histological evaluation of these transgenic pigs further illustrates the requirement for precise control of growth-related genes and their protein products.

Adipocytes↗
PubMed1994

Acute focal bacterial nephritis presented as acute renal failure and hepatic dysfunction in a renal transplant recipient.

We describe acute focal bacterial nephritis (AFBN) presented as acute renal failure and hepatic dysfunction in a renal transplant recipient. He had received a renal transplantation 5 years previously and maintained good renal function without an episode of acute rejection or any urinary abnormalities. He had been an HBsAg carrier and showed mild elevation of liver enzymes after renal transplantation. For 5 days before admission, the patient suffered from fever, graft kidney swelling, tenderness and oliguria. On admission, renal biopsy was performed and solumedrol pulse therapy was started under the impression of acute rejection. The following laboratory findings revealed acute renal failure and hepatic dysfunction. From the abdomen CT and renal biopsy findings this case was confirmed as AFBN in a grafted kidney. With successive hemodialysis and antibiotic therapy clinical symptoms and renal function improved promptly. In acute hepatic dysfunction we discontinued cyclosporine (CsA) to prevent irreversible fulminant hepatic failure until the normalization of liver function. It should be considered that AFBN must be included in the differential diagnosis of acute rejection, and the early diagnosis and treatment of AFBN is important to save the grafted kidney. In addition, early withdrawal of CsA is essential to prevent irreversible hepatic failure when infection triggers hepatic dysfunction in HBsAg-positive renal transplant recipients.

Acute Kidney Injury↗
PubMed1994

Primary aldosteronism detected after renal transplantation.

A 44-year old female was admitted to our hospital for evaluation of uncontrolled hypertension. She received renal transplantation 3 months ago and suffered from a tingling sensation and weakness on both hands. Laboratory findings (low serum potassium, low plasma renin activity and elevated plasma aldosterone level) was consistent with primary aldosteronism. Through the postural study for plasma aldosterone and the adrenal CT finding we diagnosed this case as adrenal adenoma, which was confirmed by surgical removal. A retrospective review of medical records showed that characteristic findings in primary aldosteronism (hypokalemia and low plasma renin activity) were masked by renal failure and became evident after successful renal transplantation. It was suggested that impaired urinary potassium excretion and excess release of renin from the ischemic kidney masked the characteristic findings of primary aldosteronism. To our knowledge, this is the first report documenting the change of renin-angiotensin-aldosterone system after renal transplantation in a case of coexistence of primary aldosteronism and chronic renal failure.

Adrenal Cortex Neoplasms↗
PubMed1994

Assessment of 72-kilodalton gelatinase and TIMP-1 gene expression in normal and sclerotic murine glomeruli.

Mice transgenic for bovine growth hormone (bGH) develop progressive diffuse glomerulosclerosis. Because murine mesangial cells in vitro were found to express the genes for 72-kd gelatinase and the metalloproteinase inhibitor TIMP-1, the expression of these genes in vivo in isolated whole glomeruli from bGH mice and normal control littermates was examined. Intact glomeruli were isolated by microdissection and subjected to reverse transcription. TIMP-1 cDNA was not detected by standard polymerase chain reaction (PCR) in glomeruli from bGH or control mice. In contrast, cDNA for 72-kd gelatinase was detected by standard PCR in both bGH and control mice, and the level was subsequently measured by quantitative competitive PCR. The gelatinase cDNA level was 14.7 +/- 2.8 x 10(-4) attomoles/glomerulus in 2- to 3-month-old control mice and was unchanged in 6-month-old controls. The bGH mice had 3.5-fold and 4.5-fold higher cDNA levels at 2 to 3 months and 6 months of age, respectively. Finally, zymography of glomerular extracts revealed increased levels of 72-kd and 96- to 100-kd gelatinase activity in bGH glomeruli in comparison to that in controls. In summary, whereas the genes for both TIMP-1 and 72-kd gelatinase are expressed in vitro in cultured mesangial cells, only the gelatinase gene appeared to be expressed in vivo in intact glomeruli. In addition, there was an up-regulation in the glomerular expression of the 72-kd gelatinase in bGH mice, a murine model of glomerulosclerosis.

Animals↗
PubMed1994

Five cases of cytomegalovirus infection detected by in situ hybridization and antigenemia assay.

We report five cases of cytomegalovirus infection in immunocompromised patients which were detected by either cytomegalovirus antigenemia assay or in situ hybridization. Four cases had leukemia and the other had chronic renal failure. All the three BMT recipients suffered from GvHD. Interestingly, there was an unique case of CMV disease without a history of BMT, which reminded us that CMV could attack immunocompromised patients who had not undergone transplantation, too. Four out of five cases died. We think that cytomegalovirus infection or disease should not be regarded as a minor problem in post-transplantation infection in Korea.

Adolescent↗
PubMed1994

MR imaging of sports-related muscle injuries.

Magnetic resonance (MR) imaging of the thighs of 26 baseball athletes and one softball athlete were studied to evaluate muscle injuries. We documented the abnormalities present in MR imaging after a muscle injury and evaluated the role of MR imaging in muscle injuries. Fifteen of the athletes showed muscle abnormalities in MR images. These include muscle strains without tear, muscle tear, scar and chronic tendon injury. Having the advantages of high tissue contrast and multiplanar display capability, MR allowed direct visualization of the injured muscles and characterization of traumatic lesions. We conclude that MR could be a good imaging modality for evaluating muscle injuries.

Adult↗