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Biomedical subjects

W C Yang

Publications and source records attributed to W C Yang.

At least 73 records · Page 4Linked to original sources
PubMed1997

Unusual imaging presentations in renal transitional cell carcinoma.

PURPOSE: To report on unusual imaging presentations in renal transitional cell carcinoma (TCC). MATERIAL AND METHODS: Imaging studies of 140 cases of pathologically proven renal TCC were retrospectively studied with the focus on unusual presentations. RESULTS: Unusual imaging manifestations were found in 20 cases (14.3%). These findings were classified into 5 categories: perirenal abscesses or perirenal hematomas in 6 cases; parenchymal masses in 5; undue thickening of the hydronephrotic wall in 4; "tuberculoid" pyelograms in 3; and tumors with massive necrosis in 2. CONCLUSION: Deceptive imaging presentations may occur in renal TCC. Recognition of these presentations may help to prevent delay in diagnosis.

Abscess↗
PubMed1997

Application of a sensitive and specific reagent for the determination of serum iron to the Bayer DAX48.

We describe a modification of a previously described serum iron procedure applied to the Bayer DAX48 (Bayer Diagnostics, Tarrytown, NY) automated chemistry analyzer. The iron-ligand used in this assay, 2-(5-nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamine) phenol (nitro-PAPS), has a molar absorptivity of 94,000 L mol(-1) cm(-1), which is three to four times more sensitive than the more commonly used ligands. The increased sensitivity of the iron-ligand complex facilitates modification of a Ferene S method that requires a smaller sample volume while it maintains the precision of the assay. Because the reagent does not contain ascorbate, the "onboard" stability has been increased to more than 4 weeks. The reagent seems to be quite insensitive to icterus and hemolysis. Furthermore, the interference of turbidity caused by triglycerides, abnormal proteins, or fibrinogen, present in samples from patients undergoing anticoagulant therapy, seems to have been eliminated.

Azo Compounds↗
PubMed1997

Ethylene provides positional information on cortical cell division but is not involved in Nod factor-induced root hair tip growth in Rhizobium-legume interaction.

Nod factors secreted by Rhizobium leguminosarum bv. viciae induce root hair deformation, involving a reinitiation of tip growth, and the formation of nodule primordia in Vicia sativa (vetch). Ethylene is a potent inhibitor of cortical cell division, an effect that can be counteracted by applying silver ions (Ag+) or aminoethoxy-vinylglycine (AVG). In contrast to the inhibitory effect on cortical cell division, ethylene promotes the formation of root hairs (which involves tip growth) in the root epidermis of Arabidopsis. We investigate the possible paradox concerning the action of ethylene, putatively promoting Nod factor induced tip growth whilst, at the same time, inhibiting cortical cell division. We show, by using the ethylene inhibitors AVG and Ag+, that ethylene has no role in the reinitiation of root hair tip growth induced by Nod factors (root hair deformation) in vetch. However, root hair formation is controlled, at least in part, by ethylene. Furthermore, we show that ACC oxidase, which catalizes the last step in ethylene biosynthesis, is expressed in the cell layers opposite the phloem in that part of the root where nodule primordia are induced upon inoculation with Rhizobium. Therefore, we test whether endogenously produced ethylene provides positional information controlling the site where nodule primordia are formed by determining the position of nodules formed on pea roots grown in the presence of AVG or Ag+.

Amino Acid Oxidoreductases↗
PubMed1996

A novel type of DNA-binding protein interacts with a conserved sequence in an early nodulin ENOD12 promoter.

The pea genes PsENOD12A and PsENOD12B are expressed in the root hairs shortly after infection with the nitrogen-fixing bacterium Rhizobium leguminosarum bv. viciae or after application of purified Nod factors. A 199 bp promoter fragment of the PsENOD12B gene contains sufficient information for Nod factor-induced tissue-specific expression. We have isolated a Vicia sativa cDNA encoding a 1641 amino acid protein, ENBP1, that interacts with the 199 bp ENOD12 promoter. Two different DNA-binding domains were identified in ENBP1. A domain containing six AT-hooks interacts specifically with an AT-rich sequence located between positions -95 and -77 in the PsENOD12B promoter. A second domain in ENBP1 is a cysteine-rich region that binds to the ENOD12 promoter in a sequence non-specific but metal-dependent way. ENBP1 is expressed in the same cell types as ENOD12. However, additional expression is observed in the nodule parenchyma and meristem. The presence of three small overlapping ORFs in the 5'-untranslated region of the ENBP1 cDNA indicates that ENBP1 expression might be regulated at the translational level. The interaction of ENBP1 with a conserved AT-rich element within the ENOD12 promoter and the presence of the ENBP1 transcript in cells expressing ENOD12 strongly suggest that ENBP1 is a transcription factor involved in the regulation of ENOD12. Finally, the C-terminal region of ENBP1 shows strong homology to a protein from rat that is specifically expressed in testis tissue.

Amino Acid Sequence↗
PubMed1996

Determination of dextromethorphan metabolic phenotype by salivary analysis with a reference to genotype in Chinese patients receiving renal hemodialysis.

BACKGROUND: The polymorphic metabolism of debrisoquin and sparteine by cytochrome P450IID6 (CYP2D6) is genetically determined. Determination of the CYP2D6 metabolic phenotype with conventional urine analytic methods is not feasible in anuric patients with renal failure. The possibility of using salivary analysis, with dextromethorphan as a probe drug, to determine the CYP2D6 metabolic phenotype in patients with renal failure was evaluated. METHODS AND RESULTS: One hundred four Chinese patients with renal failure were recruited. All 104 patients were receiving hemodialysis. Saliva was collected before and at 3 hours after each patient took a capsule of dextromethorphan hydrobromide (30 mg). Four patients were excluded because of insufficient samples of saliva. The distribution of logarithms of the metabolic ratios (log[MR]) in the 100 patients appeared to be normal. Administration of quinidine sulfate (200 mg twice daily) to nine of the patients significantly and markedly increased the dextromethorphan metabolic ratios. The metabolic ratios of nine patients pretreated with quinidine were higher than any of the 100 patients with renal failure who did not receive quinidine pretreatment. A metabolic ratio of 33 separated these two groups. Genomic deoxyribonucleic acid was extracted from whole blood in a subset of patients. Polymerase chain reaction (PCR)-based methods were used to detect the CYP2D6 and B mutant genes. Mutant B alleles (which are common in white poor metabolizers) of CYP2D6 genes were not detected in any of the 47 subjects tested. A PCR-based test of cytosine (C188) to thymine (T188) polymorphism at 188 base pairs in exon 1 of CYP2D6 genes was performed in 61 patients. Subjects who were homozygous for C188 had significantly (p = 0.0067) lower log[MR] values than those who were homozygous for T188. CONCLUSIONS: Determination of dextromethorphan metabolic ratios in saliva is feasible in patients with renal failure requiring hemodialysis. All subjects in this study appeared to be "extensive metabolizer" phenotype for CYP2D6, and no poor metabolizer was identified. From the results with quinidine pretreatment, a metabolic ratio of 33 is suggested to be a tentative antimode for identification of poor metabolizers in patients with renal failure.

Adult↗
PubMed1996

Urinary PCO2 for hemodynamically unstable patients.

BACKGROUND: Gastric intramural pH (pHi) derived from gastric PCO2 has been successfully used to assess splanchnic ischemia for patients with unstable hemodynamics, but with some limitations. Urinary bladder, also an easily accessible hollow viscus, should provide as a useful route for the same purpose. However, no study has used urinary PCO2 to evaluate the adequacy of perfusion in critically ill patients. METHODS: Fifty patients admitted to intensive care unit were included and divided into hemodynamically stable and unstable groups. Several parameters such as arterial pressure, dopamine dosage, heart rate, serum lactate, arterial blood gas, urinary PCO2, and concentrations of Na, K and Cl in urine were measured. Patients with some other renal or pre-renal conditions that might affect urinary PCO2 were excluded. RESULTS: Urinary PCO2 was markedly higher (78.6 +/- 9.9 vs. 43.1 +/- 1.7 mmHg, p < 0.0001) in unstable group. Serum anion gap level, dopamine dosage and heart rate were significantly higher and PaO2/FiO2 ratio as well as mean arterial pressure was lower in unstable group. Serum lactate, arterial pH and other parameters failed to distinguish between groups. Dopamine dosage significantly correlated with urinary PCO2 (r = 0.5357, p = 0.0149) in unstable group. CONCLUSIONS: With careful selection of patients, urinary PCO2 can effectively differentiate hemodynamically unstable patients from stable ones. It also correlates significantly with dopamine dosage in patients with unstable hemodynamics.

Aged↗
PubMed1995

VsENOD5, VsENOD12 and VsENOD40 expression during Rhizobium-induced nodule formation on Vicia sativa roots.

We isolated ENOD5, ENOD12 and ENOD40 homologues from Vicia sativa and studied their expression pattern during Rhizobium-induced nodule formation. Comparison of the VsENOD40 nucleotide sequence with the pea, soybean and alfalfa ENOD40 sequences showed that the sequences contain two conserved regions, called region I and region II. Comparison of all the potential open reading frames (ORFs) showed that all the five different ENOD40 clones encode a highly conserved small polypeptide of 12 or 13 amino acids encoded by an ORF located in region I. Furthermore we studied with in situ hybridization the expression pattern of VsENOD5, VsENOD12 and VsENOD40 during Rhizobium-induced nodule formation. Although the expression of these genes is largely similar to that of the pea counterparts, differences where found for the expression of VsENOD12 and VsENOD40 in Vicia. VsENOD12 is expressed in the whole prefixation zone II, whereas in pea ENOD12 is only expressed in the distal part of this zone. VsENOD40 is expressed in the uninfected cells of interzone II-III, while in pea ENOD40 is expressed in both the uninfected and infected cells of this zone.

Amino Acid Sequence↗
PubMed1995

Early nodulin gene expression during Nod factor-induced processes in Vicia sativa.

Rhizobium leguminosarum bv. viciae-secreted Nod factors are able to induce root hair deformation, the formation of nodule primordia and the expression of early nodulin genes in Vicia sativa (vetch). To obtain more insight into the mode of action of Nod factors the expression of early nodulin genes was followed during Nod factor-induced root hair deformation and nodule primordium formation. The results of these studies suggested that the expression of VsENOD5 and VsENOD12 is not required for root hair deformation. In the Nod factor-induced primordia both VsENOD12 and VsENOD40 are expressed in a spatially controlled manner similar to that found in Rhizobium-induced nodule primordia. In contrast, VsENOD5 expression has never been observed in Nod factor-induced primordia, showing that the induction of VsENOD5 and VsENOD12 expression are not coupled. VsENOD5 expression is induced in the root epidermis by Nod factors and in Rhizobium-induced nodule primordia only in cells infected by the bacteria, suggesting that the Nod factor does not reach the inner cortical cells.

Base Sequence↗
PubMed1995

Renal function in gout patients.

Patients with gouty arthritis were examined at Veterans General Hospital to evaluate whether their renal function is impaired and to define the factor(s), if any, of renal function deterioration. A total of 152 cases were included in the study, and the patients were divided into two groups. One group (n = 80) exhibited pure gout without any associated medical problems or preexisting renal disorders. The second group (n = 72) included patients with gout and hypertension. The group with pure gout was further stratified into patients with tophi (n = 21) and those without (n = 59). Seventy-two sex- and age-matched normal adults served as the control group. We found (1) that the renal function was impaired in the pure-gout group when compared with sex- and age-matched normal individuals (serum creatinine 1.56 +/- 0.64 vs. 0.90 +/- 0.16 mg/dl, p = 0.0001; creatinine clearance 59.91 +/- 30.90 vs. 97.10 +/- 27.19 ml/min, p = 0.0001); (2) that the renal function was significantly more aggravated in patients with clinically visible tophi than in those without (gout with tophi vs. gout without tophi: serum creatinine 1.89 +/- 0.90 vs. 1.44 +/- 0.48 mg/dl, p = 0.040; creatinine clearance 47.27 +/- 31.90 vs. 64.40 +/- 29.53 ml/min, p = 0.030), and (3) that a further significant decline of the renal function was noted in gouty patients with an associated medical illness, i.e., hypertension (gout with hypertension vs. pure gout: serum creatinine 2.10 +/- 0.97 vs. 1.56 +/- 0.64 mg/dl, p = 0.0001; creatinine clearance 45.06 +/- 24.69 vs. 59.91 +/- 30.90 ml/min, p = 0.0029).(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Gouty↗
PubMed1994

Characterization of a monoclonal antibody recognizing an epitope designated as canine leukocyte-associated antigen.

An IgG1 monoclonal antibody (mAb), designated as 15F1.5, was generated against surface determinants of a dog peripheral blood-derived PHA-induced IL-2-dependent T cell line. It reacted with 65-80% of peripheral blood mononuclear cells (PBMCs), 90-95% of polymorphonuclear cells (PMNs), 65-70% of thymocytes, 85-95% of Thy-1 positive cells and 85-95% of IL-2-dependent T lymphoid cells in flow cytometry. It was nonreactive with peripheral blood red cells and platelets. It immunoprecipitated 95 and 150 Kd proteins derived from detergent solubilized lymphocyte membranes. Indirect immunofluorescent and immunoperoxidase staining of frozen tissue sections demonstrated positive reactivity to cells in lymphoid but not nonlymphoid tissues. The 15F1.5 antibody was not directly mitogenic for PBMC's. It caused significant decrease (P < or = 0.05) in the lymphoproliferative response to T-dependent B cell mitogens, such as pokeweed mitogen (PWM) and staphage lysate (SPL), without significant effects on responses to the T cell mitogens, phytohemagglutinin (PHA), and concanavalin A (Con A). The mixed lymphocyte culture (MLC) response and both the proliferative and effector arms of the cell-mediated cytotoxicity reactions (CMC) were inhibited in a dose-dependent manner. The mAb also inhibited the auto- and allolymphoproliferative reactivity of mixed lymphocyte kidney or islet cell cultures (MLKC and MLIC), and the adhesion of T lymphoblasts and PMA-treated PMNs to endothelial cells. In vivo administration of the 15F1.5 (20 mg/day for 5 days) caused an immediate and prolonged reduction in MLC responses, associated with cell binding of the mAb to PBMC and epitope modulation during the course of treatment, as indicated by flow cytometry. These results suggest that 15F1.5 is an immunomodulating antibody reacting with canine LFA-1. Thus, this mAb would be useful in studying the role of LFA-1/ICAM-1 in graft rejection as well as other inflammatory responses. It would also allow the use of an animal model to investigate the immunoregulatory effects of in vivo administration of anti-CD11/CD18 antibodies in organ/tissue transplants.

Animals↗
PubMed1994

The root epidermis-specific pea gene RH2 is homologous to a pathogenesis-related gene.

Two-dimensional gel electrophoresis of pea root and root hair proteins revealed the existence of at least 10 proteins present at elevated levels in root hairs. One of these, named RH2, was isolated and a partial amino acid sequence was determined from two tryptic peptides. Using this sequence information oligonucleotides were designed to isolate by PCR an RH2 cDNA clone. In situ hybridization studies with this cDNA clone showed that rh2 is not only expressed in root hairs, but also in root epidermal cells lacking these tubular outgrowths. During post-embryonic development the gene is switched on after the transition of protoderm into epidermis and since rh2 is already expressed in a globular pea embryo in the protoderm at the side attached to the suspensor, we conclude that the expression of rh2 is developmentally regulated. At the amino acid level RH2 is 95% homologous to the pea PR protein I49a. These gene encoding I49a is induced in pea pods upon inoculation with the pathogen Fusarium solani [12]. We postulate that rh2 contributes to a constitutive defence barrier in the root epidermis. A similar role has been proposed for chalcone synthase (CHS) and chitinase, pathogenesis-related protein that are also constitutively present in certain epidermal tissues.

Amino Acid Sequence↗
PubMed1994

Comparison of soybean and pea ENOD40 cDNA clones representing genes expressed during both early and late stages of nodule development.

A pea cDNA clone representing the homologue of the soybean pGmENOD40-1 was isolated and characterized. At the nucleotide level both clones share 55% homology. Strikingly, the homology between the polypeptides derived from the pea and soybean ENOD40 cDNA sequences is only 14%. Despite this low homology Southern analyses revealed that the isolated pea cDNA clone represents the single pea ENOD40. In situ hybridizations showed that at early stages of nodule development and in mature nodules the expression pattern of pea ENOD40 is comparable to that of soybean ENOD40. Although ENOD40 show similar expression patterns in these two nodules, it is questionable whether the putative polypeptides have a similar function, since the homology is very low.

Amino Acid Sequence↗
PubMed1994

Hypokalemic effects of intravenous infusion or nebulization of salbutamol in patients with chronic renal failure: comparative study.

To examine and compare the efficacy and safety of different routes of administration of salbutamol in treating hyperkalemia, 15 patients with chronic renal failure (blood urea nitrogen > 80 mg/dL, serum creatinine > 8.0 mg/dL) were enrolled to sequentially receive either intravenous infusion (0.5 mg) or nebulization (10 mg) of salbutamol. Five of these patients (33.3%) did not respond to the intravenous salbutamol and were excluded from the study. Both treatments significantly decreased plasma potassium in 10 patients and the decrease was sustained for at least 3 hours. After infusion, the maximal reduction in plasma potassium levels was 0.92 +/- 0.10 mEq/L and occurred after 30 minutes. On the other hand, the maximal reduction in plasma potassium after nebulization (0.85 +/- 0.13 mEq/L) was similar to that after infusion, but it occurred after 90 minutes. Insulin and blood glucose increased, whereas blood pH, PCO2, sodium, osmolality, and blood pressure did not change after either treatment. Heart rate increased significantly after both treatments, but less after nebulization than after infusion. It is concluded that both infusion and nebulization are simple, effective, and safe therapeutic modalities for the treatment of hyperkalemia in patients with chronic renal failure. Infusion should be used in patients requiring a rapid decrease in plasma potassium; nebulization, on the other hand, should be used in patients with coronary artery diseases.

Administration, Inhalation↗
PubMed1994

Rhizobium nod factors reactivate the cell cycle during infection and nodule primordium formation, but the cycle is only completed in primordium formation.

Rhizobia induce the formation of root nodules on the roots of leguminous plants. In temperate legumes, nodule organogenesis starts with the induction of cell divisions in regions of the root inner cortex opposite protoxylem poles, resulting in the formation of nodule primordia. It has been postulated that the susceptibility of these inner cortical cells to Rhizobium nodulation (Nod) factors is conferred by an arrest at a specific stage of the cell cycle. Concomitantly with the formation of nodule primordia, cytoplasmic rearrangement occurs in the outer cortex. Radially aligned cytoplasmic strands form bridges, and these have been called preinfection threads. It has been proposed that the cytoplasmic bridges are related to phragmosomes. By studying the in situ expression of the cell cycle genes cyc2, H4, and cdc2 in pea and alfalfa root cortical cells after inoculation with Rhizobium or purified Nod factors, we show that the susceptibility of inner cortical cells to Rhizobium is not conferred by an arrest at the G2 phase and that the majority of the dividing cells are arrested at the G0/G1 phase. Furthermore, the outer cortical cells forming a preinfection thread enter the cell cycle although they do not divide.

Amino Acid Sequence↗
PubMed1994

Intravenous infusion or nebulization of salbutamol for treatment of hyperkalemia in patients with chronic renal failure.

BACKGROUND: Hyperkalemia is one of the frequent medical emergencies in patients with chronic renal failure (CRF). We studied and compared the efficacy and safety of salbutamol either by intravenous infusion (i.v.) or nebulization (NB) in treating CRF patients with hyperkalemia. METHODS: Thirty-four patients (BUN > 80 mg/dl, serum creatinine > 8.0 mg/dl, and plasma potassium > 5.0 mEq/L) were randomly assigned to receive either i.v. (0.5 mg) or NB (10 mg) treatment of salbutamol. Plasma potassium, sodium, osmolarity, glucose, insulin, PCO2, blood pH, blood pressure and heart rate were monitored. RESULTS: One third of i.v. group and one fourth of NB group of patients were resistant to salbutamol treatment and were excluded from the study. All the baseline data were similar between 2 groups. After treatment, significant decrease in plasma potassium was found in both groups. The maximal reduction of plasma potassium was 0.95 +/- 0.14 mEq/L and occurred 30 minutes after i.v. treatment (n = 12) while it was 0.88 +/- 0.13 mEq/L and occurred 90 minutes after NB treatment (n = 12). During the first ninety minutes after treatments, the decrease of plasma potassium in IV group was faster and greater than in NB group. After that, the hypokalemic effect was more profound in NB group till the end of the study. The hypokalemic effects of both treatments sustained for at least 3 hours. Plasma insulin and glucose increased (p < 0.05) in both groups, whereas blood pH, PCO2, sodium, osmolarity and blood pressure did not change significantly. The reduction of potassium was significantly correlated with the elevation of insulin (i.v.: r = -0.56, p < 0.05; NB: r = -0.54, p < 0.05). Heart rate elevated significantly in both groups; nevertheless, this elevation was less marked in NB group. CONCLUSIONS: Both routes of administration of salbutamol resulted in a prompt and significant decrease of plasma potassium concentrations and both are considered as simple, effective and safe alternatives in treating hyperkalemia in patients with CRF. However, i.v. therapy might be preferred in CRF patients requiring a rapid lowering in plasma potassium; nebulization, on the other hand, should be preferred in CRF patients with coronary artery diseases.

Administration, Inhalation↗
PubMed1993

The pea late nodulin gene PsNOD6 is homologous to the early nodulin genes PsENOD3/14 and is expressed after the leghaemoglobin genes.

The pea late nodulin gene PsNOD6 has been cloned and sequenced. PsNOD6 is homologous to the pea early nodulin genes PsNOD3 and PsENOD14. In situ hybridization experiments showed that, like the PsENOD3 and PsENOD14 genes, the PsNOD6 gene is only expressed in the infected cell type. The PsNOD6 gene is first expressed at the transition of the pre-fixation zone II into the interzone II-III (the amyloplast-rich zone preceding the fixation zone III), whereas the early nodulin genes PsENOD3 and PsENOD14 are already induced in the pre-fixation zone II. Thus these nodulin genes encoding homologous proteins are induced at consecutive stages of nodule development. The expression of the late nodulin genes encoding leghaemoglobin precedes the expression of the late nodulin gene PsNOD6. Therefore these late nodulin genes have to be regulated by different mechanisms despite the fact they are expressed in the same cell type. This conclusion is consistent with the fact that PsNOD6 lacks one of the conserved regions occurring in the promoters of all other late nodulin genes studied.

Amino Acid Sequence↗