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S L Wu

Publications and source records attributed to S L Wu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Structure, expression, and properties of an atypical protein kinase C (PKC3) from Caenorhabditis elegans. PKC3 is required for the normal progression of embryogenesis and viability of the organism.

Little is known about differential expression, functions, regulation, and targeting of "atypical" protein kinase C (aPKC) isoenzymes in vivo. We have cloned and characterized a novel cDNA that encodes a Caenorhabditis elegans aPKC (PKC3) composed of 597 amino acids. In post-embryonic animals, a 647-base pair segment of promoter/enhancer DNA directs transcription of the 3.6-kilobase pair pkc-3 gene and coordinates accumulation of PKC3 protein in approximately 85 muscle, epithelial, and hypodermal cells. These cells are incorporated into tissues involved in feeding, digestion, excretion, and reproduction. Mammalian aPKCs promote mitogenesis and survival of cultured cells. In contrast, C. elegans PKC3 accumulates in non-dividing, terminally differentiated cells that will not undergo apoptosis. Thus, aPKCs may control cell functions that are independent of cell cycle progression and programmed cell death. PKC3 is also expressed during embryogenesis. Ablation of PKC3 function by microinjection of antisense RNA into oocytes yields disorganized, developmentally arrested embryos. Thus, PKC3 is essential for viability. PKC3 is enriched in particulate fractions of disrupted embryos and larvae. Immunofluorescence microscopy revealed that PKC3 accumulates near cortical actin cytoskeleton/plasma membrane at the apical surface of intestinal cells and in embryonic cells. A candidate anchoring/targeting protein, which binds PKC3 in vitro, has been identified.

Amino Acid Sequence↗
PubMed1998

Single-column purification of syncephapepsin--an aspartic proteinase from Syncephalastrum racemosum.

Syncephapepsin is a fungal aspartic proteinase from Syncephalastrum racemosum. By using the property of syncephapepsin after having increased activity at higher temperature, two rapid purification protocols were developed. In the former case, a crude extract was initially diluted fivefold with an activity assay buffer and heated at 50 degrees C overnight. In this situation, syncephapepsin would digest most of the proteins that the crude extract contained. Subsequently, syncephapepsin of the crude extract was precipitated from 50 to 70% of ammonium sulfate and the preparation was then directly applied to the Superdex 200 HR FPLC column. In this manner, syncephapepsin was rapidly purified to apparent homogeneity within 24 h. In this report, an alternative method of purification is also provided. Compared with the procedure mentioned above, the heating step was proceeded after FPLC chromatography through which the same result was obtained. Using cytochrome c and RNase A as substrates, the cleavage sites of both substrates were identified by HPLC peptide mapping. The results showed that syncephapepsin had a broad specificity. Residues recognized to be cleaved were primarily those of trypsin and chymotrypsin and Lys was the most susceptible.

Amino Acid Sequence↗
PubMed1998

Identification, expression, and characterization of the pseudorabies virus DNA-binding protein gene and gene product.

The pseudorabies virus (PRV) gene encoding a DNA-binding protein (DBP) was first identified in this study. The DBP gene has an open reading frame of 3531 nucleotides, capable of coding a 1177-amino-acid polypeptide of 125 kDa. The deduced DBP exhibits a conserved zinc-binding motif and a conserved DNA-binding region, suggesting the similar DNA-binding mechanism occurs among alphaherpesviral DBP homologs. To further identify the biochemical properties of PRV DBP, this protein was expressed in Escherichia coli by using a pET expression vector and purified to homogeneity. The PRV DBP binds cooperatively and preferentially to single-stranded DNA with no significant base preference, judged by agarose gel electrophoresis and competitive nitrocellulose filter binding assays. Taken together, these results suggest that PRV DBP may play an important role in PRV DNA replication by binding cooperatively and nonspecifically to single-stranded DNA that is formed during the replication origin unwinding and replication fork movement.

Amino Acid Sequence↗
PubMed1998

Effects of high dose octreotide on retrograde bile salt-induced pancreatitis in rats.

The effects of somatostatin and octreotide (a long acting somatostatin analogue) in acute pancreatitis are inconclusive. This study examined the prophylactic and therapeutic effects of different doses of octreotide on retrograde sodium taurodeoxycholate-induced acute necrotizing pancreatitis in rats. The rats were divided into 4 groups receiving subcutaneous injection of saline, octreotide 10 microg/kg, 20 microg/kg at 0, 8 and 16 h and octreotide 20 microg/kg at 5, 13 and 21 h, separately. The serum levels of amylase and lipase, pancreatic histopathology, mortality and hemodynamics were examined. Octreotide significantly reduced serum levels of amylase and lipase at 12 h and the degree of pancreatic edema, necrosis and hemorrhage at 18-24 h as compared to the control group. Prophylactic octreotide 10 microg/kg significantly decreased the 24-h mortality from 100% to 44.4% (p < 0.05). The 24-h mortality further reduced to 12.5% and 10% with prophylactic and therapeutic octreotide 20 microg/kg, respectively. The decrease of mean arterial pressure at 12 h was significantly lower in octreotide groups than in the control group. We conclude that octreotide improves pancreatic histopathology and survival in acute necrotizing pancreatitis in rats.

Amylases↗
PubMed1998

Chronic administration of octreotide ameliorates portal hypertension and portal hypertensive gastropathy in rats with cirrhosis.

1. Portal hypertension and hyperdynamic circulation have been postulated to play a role in the pathogenesis of portal hypertensive gastropathy. Administration of octreotide to portal hypertensive rats has been shown to reduce portal pressure and ameliorate hyperdynamic circulation. 2. This study investigated the effects of chronic administration of octreotide on systemic and portal haemodynamics and the development of portal hypertensive gastropathy in carbon tetrachloride-induced cirrhotic rats. 3. After 12 weeks of carbon tetrachloride induction, cirrhotic rats were randomly assigned to receive either placebo (5% dextrose in water) or octreotide (65 micrograms/kg in 5% dextrose in water) subcutaneously twice daily for 10 days. Haemodynamic studies with a thermodilution technique and gastric morphometric analyses were performed at 10 days after treatment. 4. In cirrhotic rats, octreotide treatment induced a significant increase in systemic vascular resistance (2.7 +/- 0.2 versus 3.4 +/- 0.2 mmHg/ml.min-1.100 g-1, P < 0.05) and decrease in portal pressure (12.5 +/- 1.2 versus 9.9 +/- 0.5 mmHg, P < 0.05) compared with placebo-treated rats. In addition, octreotide treatment significantly reduced the mean cross-sectional area of gastric mucosal vessels (2290 +/- 145 versus 1810 +/- 101 micron 2, P < 0.05). 5. This study shows that chronic octreotide treatment ameliorates the development of portal hypertensive gastropathy in cirrhotic rats. The effect of octreotide on portal hypertensive gastropathy may, at least partly, be due to the alleviation of portal hypertension and hyperdynamic circulation.

Animals↗
PubMed1998

Aminoguanidine ameliorates splanchnic hyposensitivity to glypressin in a haemorrhage-transfused rat model of portal hypertension.

1. Hyposensitivity to vasopressin is a well-documented phenomenon in animals with portal hypertension and patients with cirrhosis subjected to haemorrhage. Excessive formation of nitric oxide is at least partly responsible for the vascular hyporesponsiveness to vasoconstrictors observed in experimental portal hypertension or in rats with haemorrhagic shock. This study investigated whether addition of aminoguanidine, a preferential inducible nitric oxide synthase inhibitor, to glypressin (a long-acting vasopressin analogue) could enhance its portal hypotensive effect in portal-hypertensive rats with bleeding.2. Portal hypertension was induced by partial portal vein ligation. Fourteen days after operation, systemic and portal haemodynamics were measured in stable or bleeding portal vein-ligated rats receiving intravenous glypressin (0.07 mg/kg) or aminoguanidine (70 mg/kg) followed by glypressin infusion. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was reinfused before the administration of glypressin or aminoguanidine.3. Glypressin resulted in a significantly greater decrease in portal pressure in portal vein-ligated rats without bleeding than in those with bleeding (P<0.001). In contrast, glypressin induced similar changes in mean arterial pressure between the two groups (P>0.05). The addition of aminoguanidine significantly potentiated the portal-hypotensive effect of glypressin in bleeding portal vein-ligated rats (P<0.005) without an effect on the changes in mean arterial pressure induced by glypressin infusion (P>0.05).4. Splanchnic hyposensitivity to glypressin exists in a haemorrhage-transfused rat model of portal hypertension. This hyposensitivity can be ameliorated by the administration of aminoguanidine.

Animals↗
PubMed1998

Three amino acid substitutions in the L protein of the human parainfluenza virus type 3 cp45 live attenuated vaccine candidate contribute to its temperature-sensitive and attenuation phenotypes.

Studies were initiated to define the genetic basis of the temperature-sensitive (ts), cold adaptation (ca), and attenuation (att) phenotypes of the human parainfluenza virus type 3 (PIV3) cp45 live attenuated vaccine candidate. Genetic data had previously suggested that the L polymerase protein of cp45, which contains three amino acid substitutions at positions 942, 992, and 1558, contributed to its temperature sensitivity (R. Ray, M. S. Galinski, B. R. Heminway, K. Meyer, F. K. Newman, and R. B. Belshe, J. Virol. 70:580-584, 1996; A. Stokes, E. L. Tierney, C. M. Sarris, B. R. Murphy, and S. L. Hall, Virus Res. 30:43-52, 1993). To study the individual and aggregate contributions that these amino acid substitutions make to the ts, att, and ca phenotypes of cp45, seven PIV3 recombinant viruses (three single, three double, and one triple mutant) representing all possible combinations of the three amino acid substitutions were recovered from full-length antigenomic cDNA and analyzed for their ts, att, and ca phenotypes. None of the seven mutant recombinant PIVs was cold adapted. The substitutions at L protein amino acid positions 992 and 1558 each specified a 105-fold reduction in plaque formation in cell culture at 40 degrees C, whereas the substitution at position 942 specified a 300-fold reduction. Thus, each of the three mutations contributes individually to the ts phenotype. The triple recombinant which possesses an L protein with all three mutations was almost as temperature sensitive as cp45, indicating that these mutations are the major contributors to the ts phenotype of cp45. The three individual mutations in the L protein each contributed to restricted replication in the upper or lower respiratory tract of hamsters, and this likely contributes to the observed stability of the ts and att phenotypes of cp45 during replication in vivo. Importantly, the recombinant virus possessing L protein with all three mutations was as restricted in replication as was the cp45 mutant in both the upper and lower respiratory tracts of hamsters, indicating that the L gene of the cp45 virus is a major attenuating component of this candidate vaccine.

Animals↗
PubMed1998

RET protooncogene mutations in patients with apparently sporadic medullary thyroid carcinoma.

We examined RET protooncogene mutations in sporadic medullary thyroid carcinoma (MTC), using polymerase chain reaction (PCR)-based sequencing. DNA was extracted from tumor tissue and peripheral blood leukocytes of seven unrelated individuals with apparently sporadic MTC. Oligonucleotide primers were selected to amplify exons 10, 11, 13, 15, and 16 of the RET protooncogene, to examine the sequences of codons 609, 611, 618, and 620 of exon 10, codon 634 of exon 11, codon 768 of exon 13, codon 883 of exon 15, and codon 918 of exon 16. Direct DNA sequencing from PCR products was then performed. The results showed that one patient had a somatic mutation at codon 918 (ATG-->ACG), causing a Met-->Thr substitution. One patient had a de novo germline mutation at codon 634 (TGC-->CGC), causing a Cys-->Arg substitution. Another patient had a germline mutation at codon 634 (TGC-->TTC), causing a Cys-->Phe substitution. In the remaining four cases, no RET mutations were found. Unexpectedly, two offspring of the patient (a female) with a germline mutation at codon 634 (TGC-->TTC) harbored homozygous alleles for the mutation; because the father did not carry this mutation, the other affected allele was suspected to have resulted from a de novo germline mutation of paternal origin. One of these offspring was subsequently diagnosed as having MTC. Our findings suggest that all patients with apparently sporadic MTC should be screened for the RET protooncogene by molecular analysis to detect occult or de novo multiple endocrine neoplasia 2 (MEN 2) or familial MTC. This would allow early treatment of affected family members.

Adult↗
PubMed1998

Germline RET proto-oncogene mutations in two Taiwanese families with multiple endocrine neoplasia type 2A.

To elucidate the germline RET proto-oncogene mutations in Taiwanese families with multiple endocrine neoplasia type 2A (MEN 2A), we extracted DNA from peripheral blood leukocytes of 28 members of two families with MEN 2A. Oligonucleotide primers for exons 10 and 11 were used to analyze the nucleotide sequence of codons 609, 611, 618, and 620 of exon 10, and codon 634 of exon 11 of the RET proto-oncogene. Two fragments of genomic DNA were amplified by polymerase chain reaction (PCR). The amplified PCR products were separated and purified from primers and free nucleotides in agarose gels, and the expected 187-bp and 234-bp bands were cut from the gels and sequenced. Thirteen family members in the two MEN 2A kindreds had mutations in codon 634 of exon 11. In kindred 1 (15 members available for this study), a heterozygous codon 634 mutation in nine members and a homozygous codon 634 mutation in one member led to the substitution of Phe (TTC) for Cys (TGC). Three members of kindred 2 (13 members available for this study) had a heterozygous base pair change in codon 634, which led to the substitution of Arg (CGC) for Cys (TGC). In this study, we found two mutation events occurring in two MEN 2A kindreds and also discovered a homozygous point mutation in one woman that led to heterozygous mutations in all of her children.

Drosophila Proteins↗
PubMed1997

The use of sequential high-performance liquid chromatography and capillary zone electrophoresis to separate the glycosylated peptides from recombinant tissue plasminogen activator to a detailed level of microheterogeneity.

The advantage of using the two-dimensional separation method was demonstrated by the separation of the complex tryptic peptides of recombinant human tissue plasminogen activator (rt-PA) glycoprotein. This method hybridizes two analytical methods where fractions containing glycopeptides are collected from reversed-phase high-performance liquid chromatography (RP-HPLC) and separated by capillary zone electrophoresis (CZE). CZE readily resolved carbohydrate structural variants, based on sialic acid content and branching, on the same peptide. Nonglycosylated peptides incidentally collected in the same RP-HPLC fraction were well resolved from the glycopeptides. This combination of RP-HPLC and CZE was able to uniquely resolve all of the peptides and glycopeptide variants in rt-PA. Confirmation of the specific peaks in the CZE was made by matrix-assisted laser-induced ionization time-of-flight mass spectrometry. The advantages and disadvantages of the existing methods for carbohydrate characterization in the biotech industry were compared. The advantage of this approach is to provide a simple extension of the existing tryptic digest protocols to include carbohydrate analysis to a detailed level of microheterogeneity.

Amino Acid Sequence↗
PubMed1997

Effects of long-term administration of octreotide on sodium retention and atrial natriuretic peptide in carbon tetrachloride-induced cirrhotic rats.

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.

Animals↗
PubMed1997

Aminoguanidine corrects hyperdynamic circulation without ameliorating portal hypertension and portal hypertensive gastropathy in anesthetized portal hypertensive rats.

BACKGROUND/AIMS: Portal hypertension and hyperdynamic circulation (i.e. generalized vasodilation and increased cardiac output and regional organ blood flows) may play an important role in the development of portal hypertensive gastropathy. This study investigated the effect of chronic administration of aminoguanidine, a selective inducible nitric oxide synthase inhibitor, to portal hypertensive rats on hemodynamics and the development of portal hypertensive gastropathy. METHODS: Partial portal vein-ligated or sham-operated rats were randomly assigned to receive either placebo (distilled water) or aminoguanidine (approximately 100 mg/kg per day subcutaneously) for 2 days prior to and 14 days. Hemodynamic studies with a thermodilution technique and gastric morphometric analysis were performed at 14 days after the operation. RESULTS: In rats given placebo, portal vein-ligated rats had a significantly lower mean arterial pressure and systemic vascular resistance associated with a significantly higher cardiac index and portal pressure than sham-operated rats (p<0.05). In portal vein-ligated rats aminoguanidine induced a significant increase in mean arterial pressure and systemic vascular resistance accompanied by a significant decrease in cardiac index (p<0.05) without changes in portal pressure (p>0.05). Despite persistence of portal hypertension, the aminoguanidine-treated portal vein-ligated rats had similar mean arterial pressure, cardiac index, and systemic vascular resistance as seen in placebo-treated sham-operated rats. The mean cross-sectional area of gastric mucosal vessels was significantly higher in placebo-treated portal vein-ligated than in placebo-treated sham-operated rats (p<0.05). Treatment with aminoguanidine did not induce changes in the mean cross-sectional area of gastric mucosal vessels in either portal vein-ligated or sham-operated rats (p>0.05). CONCLUSIONS: The results show that in portal hypertensive rats long-term aminoguanidine therapy corrects the hyperdynamic circulation without inducing changes in portal pressure and ameliorating the development of portal hypertensive gastropathy. This study suggests that, instead of correcting hyperdynamic circulation, treatment of portal hypertensive gastropathy should be aimed at reducing portal pressure.

Animals↗
PubMed1997

Hemodynamic studies and esophageal morphometric analyses in portal hypertensive rats with left adrenal vein ligation.

BACKGROUND: Despite many attempts to create esophageal varices in experimental animals, most of them have failed. This study investigated whether rats with partial portal vein ligation (PVL) and left adrenal vein ligation (LAL) develop hyperdynamic circulation and dilated esophageal submucosal veins as compared with sham-operated (Sham) plus LAL rats. METHODS: Two series of experiments were performed to measure (a) systemic and portal hemodynamics and (b) the cross-sectional area of esophageal submucosal veins in Sham, PVL, Sham plus LAL, and PVL plus LAL rats. Hemodynamic studies with a thermodilution technique and esophageal morphometric analyses were performed 14 days after the operation. RESULTS: PVL rats with or without LAL had a significantly lower mean arterial pressure and systemic vascular resistance accompanied by a significantly cardiac index and portal pressure than Sham rats with or without LAL (P < 0.05). LAL did not induce changes in mean arterial pressure, cardiac index, systemic vascular resistance, hear rate, or portal pressure in either Sham or PVL rats (P > 0.05). The mean cross-sectional area of esophageal submucosal veins in PVL rats with LAL (7340 +/- 833 microns2) was significantly larger than that in Sham rats with LAL (4236 +/- 556 microns2; P < 0.05). There was no significant difference in the mean cross-sectional area of esophageal submucosal veins between PVL and Sham rats without LAL. CONCLUSIONS: PVL rats with LAL developed hyperdynamic circulation similar to PVL rats without LAL. In addition, PVL plus LAL rats had larger esophageal submucosal veins than Sham plus LAL rats. This study shows that the esophageal submucosal veins of the 14-day partially portal vein-ligated rats with LAL resemble the structural abnormalities observed in human esophageal varices, suggesting that this model could be useful to investigate this entity.

Adrenal Glands↗
PubMed1997

Hyperdynamic circulation of cirrhotic rats: role of substance P and its relationship to nitric oxide.

BACKGROUND: It has been suggested that excessive formation of nitric oxide (NO) is responsible for the hyperdynamic circulation observed in portal hypertension. Substance P is a neuropeptide partly cleared by the liver and causes vasodilatation through the activation of the endothelial NO pathway. However, there are no previously published data concerning the plasma level of substance P in cirrhotic rats and its relationship to NO. METHODS: Plasma concentrations of substance P and nitrate/nitrite (an index of NO production) were determined in control rats and cirrhotic rats with or without ascites using an enzyme-linked immununosorbent assay and a colorimetric assay, respectively. In addition, systemic and portal hemodynamics were evaluated by a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with and without ascites had a lower systemic vascular resistance (2.6 +/- 0.2 and 3.9 +/- 0.4 mmHg ml(-1) x min x 100 g body weight, respectively) and higher portal pressure (14.6 +/- 0.6 and 11.3 +/- 1.8 mmHg) than control rats (6.5 +/- 0.3 mmHg x ml(-1) x min x 100 g BW and 6.8 +/- 0.2 mmHg, respectively, P < 0.05), and cirrhotic rats with ascites had the lowest systemic vascular resistance. Plasma levels of nitrate/nitrite progressively increased in relation to the severity of liver dysfunction (control rats, 2.7 +/- 0.5 nmol/ml; cirrhotic rats without ascites, 5.6 +/- 1.3 nmol/ml; cirrhotic rats with ascites, 8.3 +/- 2.2 nmol/ml; P < 0.05). Cirrhotic rats with ascites displayed higher plasma values of substance P (57.7 +/- 5.9 pg/ml) than cirrhotic rats without ascites (37.9 +/- 3.1 pg/ml, P < 0.05) and control rats (30.1 +/- 1.0 pg/ml, P < 0.05). There was no significant difference in plasma substance P values between control rats and cirrhotic rats without ascites (P > 0.05). No correlation was found between plasma levels of substance P and nitrate/nitrite (r = 0.318, P > 0.05). CONCLUSIONS: Excessive formation of NO may be responsible, at least partly, for the hemodynamic derangements in cirrhosis. Although substance P may not participate in the initiation of a hyperdynamic circulation in cirrhosis, it may contribute to the maintenance of the hyperdynamic circulation observed in cirrhotic rats with ascites.

Analysis of Variance↗
PubMed1997

Hyperdynamic circulation in prehepatic portal hypertension: role of tumor necrosis factor-alpha.

BACKGROUND: Portal hypertension is associated with a hyperdynamic circulation characterized by increased cardiac output and reduced systemic vascular resistance. Tumor necrosis factor-alpha (TNF-alpha) is a peptide mediator released by mononuclear cells on activation by endotoxin, tissue injury and malignancy. This cytokine induces vasodilatation by activating nitric oxide synthesis. The aim of this study is to investigate if TNF-alpha is involved in the pathogenesis of hyperdynamic circulation observed in portal vein-ligated (PVL) rats. METHODS: Systemic and portal hemodynamics were determined in seven PVL and five sham-operated (SHAM) rats using a thermodilution technique. In addition, plasma TNF-alpha concentrations were determined in another 34 PVL and 16 SHAM rats using commercially available enzyme-linked immunosorbent assay. RESULTS: PVL rats had a significantly lower mean arterial pressure (109 +/- 17 mmHg vs. 133 +/- 12 mmHg, p < 0.001) and systemic vascular resistance (2.5 +/- 0.6 mmHg.ml-1.min.100 g BW vs. 4.6 +/- 0.8 mmHg.ml-1.min.100 g BW, p < 0.001) accompanied by a significantly higher portal pressure (14 +/- 1.9 mmHg vs. 9 +/- 2.1 mmHg, p < 0.001) and cardiac index (47.0 +/- 12.1 ml.min-1.100 g BW-1 vs. 29.3 +/- 3.5 ml.min-1.100 g BW-1, p < 0.001) when compared with SHAM rats. Also, PVL rats had significantly higher plasma levels of TNF-alpha as compared with SHAM rats (13.8 +/- 0.9 pg/ ml vs. 11.1 +/- 0.5 pg/ml, p < 0.05). CONCLUSIONS: This study suggests that elevated plasma levels of TNF-alpha observed in PVL rats may participate in the development and/or maintenance of the hyperdynamic circulation occurring in prehepatic portal hypertension.

Animals↗
PubMed1996

Cloning and sequencing of complete thyrotropin receptor transcripts in pretibial fibroblast culture cells.

Pretibial fibroblasts are considered to be targets of autoimmune attack in pretibial myxedema. A possibility of the pathogenesis of pretibial myxedema is that T cells, reacting with thyrotropin (TSH) receptor, will be targeting to the pretibial fibroblasts where, in the presence of antigen (TSH receptor), they will secrete various cytokines and stimulate fibroblasts to secrete glycosaminoglycans. We have demonstrated that TSH and TSH receptor antibody can bind to fibroblasts and the presence of RNA encoding the extracellular domain of the TSH receptor in fibroblasts derived from skin lesions of two patients with pretibial myxedema. The present study was designed to determine whether there are complete TSH receptor transcripts in pretibial fibroblasts obtained from patients with pretibial myxedema. RNA was prepared from pretibial fibroblasts obtained from 11 patients with pretibial myxedema and from four normal subjects, then reverse-transcribed by polymerase chain reaction using three sets of primers (-11/+8 and +754/+773; +353/+373 and +1265/+1285; +1000/+1017 and +2284/+2301). The overlapped 2312 bp cDNA sequence was expected to contain the genetic sequences of the signal peptide (+1/+60), extracellular domain (+61/+1254), transmembrane domain (+1255/+2046), and cytoplasmic domain (+2047/ +2292) of the TSH receptor. The sequences were determined using dideoxy sequencing method. All of the 2312 nucleotide sequences in 15 samples were consistent with the reported TSH receptor sequence of transcripts in thyroid. These data suggest that the complete TSH receptor transcripts are very possible to be present in the fibroblasts derived from pretibial skin.

Adult↗