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At least 433 records · Page 24Linked to original sources
PubMed2002

[Long-standing high-transport membrane as a risk factor for EPS development after PD withdrawal: an analysis based on changes in peritoneal function during and after CAPD withdrawal].

The pathophysiology of encapsulating peritoneal sclerosis (EPS) that develops after withdrawal from long-standing dependence on CAPD remains unclear. The aim of this study was to clarify the risk factors for EPS as expressed in the peritoneal function. Fourteen patients who had shifted to standard hemodialysis after long-term CAPD (average, 105 months) were studied: 3 developed EPS after PD withdrawal while 11 did not. Analysis of the data obtained from the peritoneal equilibration test (PET) revealed that: (1) the dialysate/plasma creatinine ratio (D/Pcr) was significantly higher in the EPS group than in the non-EPS group during the course of PD as well as after PD withdrawal; and (2) eight patients, including the 3 with EPS, were classified as being in a high-transport membrane state (HTS) at PD withdrawal. The duration of HTS during PD was longer in those patients with EPS. During the periods after PD withdrawal, none of these EPS patients recovered from HTS, whereas 4 of the 5 non-EPS patients did. These data suggest that long-standing HTS during the course of PD as well as post-withdrawal, may be risk factors for EPS development. For this reason, it is indicated that PET has clinical relevance in examining sequential changes in peritoneal function and in detecting those patients at risk of EPS.

Adult↗
PubMedDate not supplied

IFN gamma-induced up-regulation of PD-ECGF/TP enhances the cytotoxicity of 5-fluorouracil and 5'-deoxy-5-fluorouridine in bladder cancer cells.

BACKGROUND: PD-ECGF/TP is an essential enzyme in converting 5'DFUR and 5FU to their active metabolites and can be up-regulated by some cytokines. MATERIALS AND METHODS: PD-ECGF/TP mRNA and protein expressions were determined by RT-PCR and Western blot, respectively. The cytotoxicity of 5FU, 5'DFUR or MMC against RT-4 and T24 cells was evaluated by MTS assay. The PD-ECGF/TP expressions in primary bladder cancers were also analyzed. RESULTS: Levels of PD-ECGF/TP mRNA and protein were concomitantly elevated in RT-4 and T24 cells after IFN gamma treatment. IFN gamma decreased the IC50 of 5FU and 5'DFUR in both cell lines, while it did not alter the IC50 of MMC, which is not a substrate of PD-ECGF/TP. PD-ECGF/TP expression correlated with tumor stage and grade in primary bladder cancers. CONCLUSION: IFN gamma enhances the cytotoxicity of 5FU and 5'DFUR against human bladder cancer cells through induction of PD-ECGF/TP. The results imply that an IFN gamma/5FU or IFN gamma/5'DFUR combination therapy may be applicable to clinical bladder cancers.

Adult↗
PubMed1977

G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia.

The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G-6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

Adult↗
PubMed2001

[Study on the interaction between Pd(II) and Rhus vernicifera laccase].

The influence of the mixing time of Pd(II) and Rhus vernicifera laccase on the oxidation of 5,6-dibromo-2,3-dicyanohydroquinone (DDBQH2) catalyzed by laccase has been studied through spectrophotometer at pH 4.5 and (30 +/- 0.1 degree C). The activation of Pd(II) on the laccase activity is gradually converted into inhibition and ultimately inactivation with the extension of the mixing time of Pd(II) and laccase, and the rate of such conversion goes up with the increase of Pd(II) concentration. The influence of Pd(II) on the absorption spectrum of laccase suggests that it is the type I site in laccase with which Pd(II) interacts and Pd(II) may gradually and at last substitute Cu(II) from the site. The substitution may be the cause of decrease and disappearance of laccase activity.

Binding Sites↗
PubMedDate not supplied

Biocompatibility of a bicarbonate/lactate-buffered PD fluid tested with a double-chamber cell culture system.

OBJECTIVE: In peritoneal dialysis (PD), neutrally buffered PD fluids with lower concentrations of glucose degradation products (GDP) have tested superior to conventional fluids in terms of biocompatibility. However, conventional in vitro studies provoke debate because, due to the lack of subsequent equilibration with the blood, they do not resemble the true intraperitoneal situation of PD. METHODS: We established a double-chamber cell culture system with peritoneal mesothelial cells seeded on top of a permeable membrane, with a physiological buffer below. Thus adequately reflecting the in vivo equilibration pattern, we compared a conventional fluid with a neutral bicarbonate/lactate-buffered PD solution. Using an exchange pattern adapted from an 8-hour continuous ambulatory PD regimen, cell viability was assessed with an MTT assay, and cell function via constitutive and stimulated interleukin (IL)-6 release. As an indicator of potential induction of fibrosis and as a parameter of mesothelial cell integrity, respectively, transforming growth factor-beta 1 (TGF-beta1) generation and cancer antigen 125 (CA125) release were measured. RESULTS: The conventional solution significantly compromised mesothelial cell viability and function in terms of mitochondrial activity (p < 0.05) and stimulated IL-6 release (p < 0.05). The bicarbonate/lactate fluid had no effect on cell viability or IL-6 release and turned out to be equivalent to the properties of the growth medium. Whereas lactate-incubated cells did not respond to IL-1beta stimulation, bicarbonate/lactate-treated cells adequately increased IL-6 release after stimulation (p < 0.0005). Release of TGF-beta1 and CA125 did not differ between the different fluids and the control. CONCLUSIONS: Due to the sustained equilibration process, the double-chamber cell culture model allows a more realistic insight into mesothelial cell viability and function in terms of PD. As in classic in vitro studies, an adverse effect of conventional PD solutions on mesothelial cells was overt in the present cell culture system. The neutral bicarbonate/lactate-buffered fluid with low GDP content, however, did not interfere with mesothelial cell vitality or function, indicating superior biocompatibility.

Bicarbonates↗
PubMed1979

[Investigation of Pd-Ag alloy for porcelain fusing. (Part 3) Mechanical properties (author's transl)].

The most suitable composition of Pd-Ag alloys added In and/or Sn for porcelain fusing was determined by means of the measurement of the mechanical properties (tensile strength, elongation and hardness). The results were summarized as follows: (1) This highest tensile strength was obtained when 5% In and 5% Sn, or 10% Sn were added to the 60 Pd-40 Ag mother alloy, and it was about 52 kgf/mm2 (570 MPa). (2) The effect of the addition of In and Sn to the tensile strength depended on the concentration of Pd and Ag. (3) The elongation increased with increase of the amount of Pd. (4) The Vickers hardness number of the alloys was ranged between 100 and 200. It increased with increase of Ag or Sn content. (5) The most suitable compositions of Pd-Ag alloys for porcelain fusing deduced from the properties such as the bonding strength (in part 1), the thermal expansion coefficient (in part 2) and the mechanical properties (in this paper) were 60 Pd-40 Ag or 64 Pd-36 Ag with addition of 4 Sn-6 In or 8 Sn-2 In. Some characteristic properties of these alloys were as follows; the bonding strength 220 kgf/cm2 (22 MPa), thermal expansion coefficient 14.7 +/- 1x10(-6)/degrees C, thermal expansion hysteresis. 0.00 approximately 0.02%, tensile strength 51 kgf/mm2 (500 MPa), elongation 5% and Vickers hardness number 160 approximately 190.

Dental Alloys↗
PubMed1981

[The fluidity of alloys in high temperature. (Part 2) The fluidity of 20% Au-Ag-Pd-Cu alloy (author's transl)].

The flow length of 20% Au-Ag-Pd-Cu alloy in the mold heated up to 650 degrees C was measured by the apparatus reported in the previous paper with partial improvement added. The results were summarized as follows. (1) The flow length of Au-Ag-Pd-Cu alloy containing 20% Au in the mold heated up to 650 degrees C increased as the content of Cu increased in the range of 10-20% Pd; however, in the range of more than 22% Pd, it decreased as the content of Pd increased. (2) The maximum flow length was obtained around the composition of 20 Au-40 Ag-15 Pd-25 Cu. On the other hand the minimum flow length was obtained around the composition of 20 Au-65 Ag-10 Pd-5 Cu. (3) There was no correlation between the flow length and both of the melting point and the melting range solidifying area.

Copper↗
PubMed1981

The influence of G-6-PD activity on the response of erythrocyte glutathione reductase to riboflavin deficiency.

Erythrocyte NAD(P)H2 glutathione oxidoreductase (EC 1.6.4.2.) activation coefficients (EGR AC) and D-glucose-6-phosphate: NADP 1-oxidoreductase, EC 1.1.1.49 (G-6-PD) activities were measured in 155 West African women to determine whether heterozygous G-6-PD deficiency produces false negative results in the EGR test for riboflavin deficiency. A positive correlation was found between EGR AC and G-6-PD activity demonstrating that heterozygous G-6-PD deficiency does result in abnormally depressed EGR AC values when G-6-PD activity is significantly reduced. However, heterozygous deficient genotypes with normal G-6-PD activity showed undepressed EGR AC values. These results indicate that, in its present form, the EGR test is not a suitable index of riboflavin status in subjects whose G-6-PD activity is less than 9 IU/g Hb when measured by the WHO-37 degrees assay.

Adult↗
PubMed1995

Molecular heterogeneity of G-6-PD deficiency in Mexico.

DNA samples from seven G-6-PD deficient Mexican mestizo patients were analyzed. Three different G-6-PD genotypes were observed: G-6-PD A-202A/376G (three patients), G-6-PD A-376G/968C (three patients) and G-6-PD Seattle844C. The present results, along with previous reports, suggest not only G-6-PD A-genotypes are relatively common but also G-6-PD deficiency seems to be heterogeneous at DNA level in Mexico.

Africa↗
PubMed1995

Pharmacological characterization of PD 156707, an orally active ETA receptor antagonist.

We describe the pharmacological characteristics of PD 156707 (sodium 2-benzo[1,3]dioxol-5-yl-4-(4-methoxy-phenyl)-4-oxo-3-(3,4,5- trimethoxy-benzyl)-but-2-enoate), a potent, orally active, nonpeptide antagonist of the endothelin A (ETA) receptor subtype. PD 156707 was designed on the basis of a compound identified by screening the Parke-Davis chemical library. PD 156707 is highly selective for the ETA receptor (ETAR) and inhibits the binding of [125I]-ET-1 to cloned human ETAR and ETBR with Ki values of 0.17 and 133.8 nM, respectively. PD 156707 antagonizes ET-1-stimulated phosphoinositide hydrolysis in Ltk- cells expressing cloned human ETAR with an IC50 value of 2.4 nM. PD 156707 inhibits vasoconstriction in isolated blood vessels mediated by ETAR (rabbit femoral artery) and ETBR (rabbit pulmonary artery) with pA2 values of 7.5 and 4.7, respectively. PD 156707 administered orally to rats blocked subsequent ETAR-mediated pressor responses in vivo but had no effect on ETBR-mediated dilator responses. As a potent and orally active ETA-selective antagonist, PD 156707 will be useful in defining the physiological and pathological roles of ETAR.

Administration, Oral↗
PubMed1994

Behavioral effects of the dopamine autoreceptor agonist PD 128483 alone and in combination with cocaine.

Many of the behavioral effects of cocaine are thought to be mediated via dopamine (DA) reuptake inhibition and a subsequent increase in DA activity. As a DA agonist with selectivity for autoreceptors, PD 128483 has behavioral effects consistent with decreased DA neurotransmission and might be expected to attenuate the behavioral effects of cocaine. The present study was designed to evaluate PD 128483 ((+)-4,5,5a,6,7,8-hexahydro-6-methyl-thiazolo[4,5-f]quinoline-2-amine) alone and in combination with cocaine in three behavioral paradigms. One group of rhesus monkeys (n = 7) was allowed to self-administer cocaine (0.03 or 0.1 mg/kg/injection i.v., fixed-ratio 10, 2 hr/day) in baseline sessions. When behavior was stable, PD 128483 (0.01-0.3 mg/kg/injection i.v.) was made available for self-administration, and failed to maintain responding in three of four monkeys tested. PD 128483 (1.0-10.0 mg/kg i.m.) decreased cocaine self-administration in all four monkeys tested when given before cocaine availability. Another group of monkeys (n = 4) was trained to discriminate cocaine (0.2 or 0.4 mg/kg i.m.) from saline in a two-lever, food-reinforced drug discrimination paradigm. High doses of PD 128483 (3.2-12.8 mg/kg i.m.) substituted for cocaine as a discriminative stimulus in three of four monkeys. Administered in combination with cocaine, PD 128483 had little effect on the cocaine discriminative stimulus up to doses which decreased response rate. PD 128483 (1.0-2.0 mg/kg i.p.) decreased milk intake in rats (n = 9) and, when given in combination with cocaine, shifted the cocaine dose-response function (4.0-16.0 mg/kg i.p.) to the left.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoquinolines↗
PubMed1995

Inhibition of basic fibroblast growth factor-mediated tyrosine phosphorylation and protein synthesis by PD 145709, a member of the 2-thioindole class of tyrosine kinase inhibitors.

PD 145709, which represents one member of a new structural class of tyrosine kinase inhibitors, the thioindoles, inhibited basic fibroblast growth factor (bFGF)-mediated tyrosine phosphorylation in Swiss 3T3 murine fibroblasts. Half-maximal suppression was attained when cells were exposed for 2 h to 4.5 microM. Little or no inhibition of epidermal growth factor (EGF)- or platelet-derived growth factor (PDGF)-mediated tyrosine phosphorylation was observed at concentrations as high as 50 microM. The inhibition of bFGF-mediated phosphorylation occurred rapidly with maximal effects occurring after the cells were exposed to PD 145709 for 90 min. Once established, the inhibition was irreversible and remained for at least 2 h after PD 145709 was removed from the extracellular medium. PD 145709 also inhibited bFGF-mediated phosphorylation as well as FGF receptor autophosphorylation in a human breast carcinoma, MDA-MB-134, which overexpresses the FGF1 receptor. PD 145709 caused an increase of c-jun mRNA in response to EGF, PDGF, bFGF and serum. This effect may be due to the fact that this compound was a potent inhibitor of protein synthesis in cells and may cause superinduction of growth factor-mediated gene expression similar to other inhibitors of protein synthesis. Inhibition of protein synthesis occurred in fibroblasts exposed to PD 145709 with half-maximal inhibition at 0.5 microM, but not in an in vitro translation system at concentrations as high as 20 microM. This indicates that an intact viable cell is necessary for inhibition to occur and is compatible with a mechanism by which PD 145709 interferes with signals or protein factors that are involved with the initiation or protein synthesis.

3T3 Cells↗
PubMed1996

Heat-sterilized PD fluid blocks leukocyte adhesion and increases flow velocity in rat peritoneal venules.

Data from cell culture experiments indicate that heat sterilization of peritoneal dialysis (PD) fluids produces cytotoxic glucose degradation products. The present vital microscopic study investigated the effects of different sterilization methods on the biocompatibility of PD fluids. Thus, heat-sterilized (commercially obtained and experimentally produced) and filter-sterilized PD fluids (pH = 5.30-5.40; 1.5% glucose) were compared with Tyrode buffer, with respect to the effects on microvascular blood flow velocity and leukocyte adhesion in the rat mesentery. Exteriorization of the mesentery produced a mild inflammation, known from the literature and characterized by the adhesive rolling of leukocytes along venular walls. Superfusion of the mesentery with filter-sterilized PD fluid had no significant effects on leukocyte rolling or flow velocity in venules 25-40 microns in diameter compared with buffer superfusion. Heat-sterilized PD fluid decreased the concentration of rolling leukocytes and increased flow velocity significantly, as compared with buffer and filter-sterilized PD fluid. The results indicate that heat sterilization of PD fluids produces substances that interact with microvascular tone and leukocyte-endothelial adhesion, which hypothetically could impair the acute, granulocyte-mediated defense against bacterial infections.

Animals↗
PubMed1996

Less infusion pain and elevated level of cancer antigen 125 by the use of a new and more biocompatible PD fluid.

Our objective was to investigate the clinical effect of a less toxic and less acidic peritoneal dialysis (PD) fluid produced in a two-compartment bag (PD-Bio). The study had an open cross-over design in 4 stable patients, where the patient served as his/her own control. After a period of three months using conventional PD fluid the patients were switched to three months on the new PD fluid. Routine blood chemistry and transport characteristics were measured. Cell samples from overnight spent dialysis fluid were analyzed for viability, differential count, release of superoxide radicals, and cancer antigen 125 (CA 125). Subjective patient symptoms and handling properties were investigated by a patient questionnaire. Cancer antigen 125 increased significantly, and patients with discomfort or infusion pain during the control period improved during the PD-Bio period. Patient acceptance with respect to handling of the two-compartment bag was excellent and did not differ from the use of standard bags. No changes were seen in the cell samples from spent dialysate, blood chemistry, or transport characteristics between the two treatment periods. PH in the effluent dialysate was, however, significantly higher for PD-Bio at all times during the two-hour dwell. Our results suggest that a PD fluid produced to minimize the level of toxic glucose degradation products and to obtain a more physiological pH has an impact on CA 125 levels, reduces pain and discomfort in connection with infusion of fluid, and does not influence the transport characteristics.

CA-125 Antigen↗
PubMed1997

Expression and transcriptional regulation of the PD-Ialpha/autotaxin gene in neuroblastoma.

Autotaxin (ATX) is a newly found autocrine tumor cell motility-stimulating factor. ATX is a member of the ecto-phosphodiesterase I (PD-I)/ nucleotide pyrophosphatase family. PD-Ialpha was found as a brain-type ecto-phosphodiesterase I/nucleotide pyrophosphatase. ATX and PD-Ialpha are alternative splicing products from one gene. ATX stimulates motility of A2058 melanoma cells in vitro; however, it has not been known if PD-Ialpha/ATX is expressed in naturally occurred human tumors. In this study, we examined the expression of the human PD-Ialpha/ATX gene in human neuroblastoma tumor tissues and the motility stimulating activity of recombinant ATX on neuroblastoma cells and investigated its transcriptional regulatory mechanism in a human neuroblastoma cell line. The PD-Ialpha/ATX gene was expressed in the primary tumor tissues from neuroblastoma patients to varying degrees. This gene is also expressed in the SMS-KAN neuroblastoma cell line. We identified both isoforms, PD-Ialpha and ATX, in these tumor tissues and SMS-KAN cells. The recombinant ATX stimulated the motility of SMS-KAN cells at low nanomolar concentration. We situated the promoter region, which is essential for its transcription in SMS-KAN cells, at -287 to -254 nucleotides by the promoter activity assay. The gel-shift assay revealed that there exists a nuclear protein in SMS-KAN cells that binds this region. These new insights about autocrine tumor cell motility-stimulating protein will help us to understand the metastatic mechanism of human neuroblastoma.

Cell Movement↗
PubMed1998

Assessment of PD treatment delivered by 125I-Iothalamate plasma disappearance.

The calculation of treatment delivered to PD patients requires the collection of PD effluent, plasma and urine samples. 125I-Iothalamate plasma disappearance, which eliminates the need for PD effluent collections, was tested as an alternate method to measure the weekly PD treatment delivered. Two protocols were designed. In protocol A, a 35 microCi dose of 125I-Iothalamate was injected in three subjects and allowed to equilibrate. A plasma sample was taken and patients returned on both of the following two days with timed labeled effluent bags and a 24-hour urine collection for each day. The timed PD effluent and 24-hour urine collections were measured for 125I-Iothalamate, urea and creatinine concentrations. 125I-Iothalamate and urea clearances were strongly correlated for both PD (R2 = 0.76, n = 24) and renal (R2 = 0.92, n = 6) clearances. In protocol B, thirteen subjects were given a 35 microCi injection of 125I-Iothalamate. A blood sample was taken one hour post injection and a second blood sample taken on day five. Kt/V were calculated from the 125I-Iothalamate plasma disappearance curve and compared to weekly Kt/V values extrapolated from one day's collections (Traditional Method). The comparison of Kt/V values found by 125I-Iothalamate Method vs. the "Traditional Method" yielded R2 = 0.79, n = 13. In conclusion, the plasma disappearance of 125I-Iothalamate is an alternate method of determining weekly Kt/V, over an extended period of time, which eliminates the need for PD effluent collections.

Creatinine↗
PubMedDate not supplied

Clinical validation of PD Adequest software: modeling error assessment.

OBJECTIVE: PD ADEQUEST software (Baxter Healthcare, Deerfield, IL, U.S.A.) is used in peritoneal dialysis for calculating the indices of dialysis efficiency and for the mathematical simulation of the results of various dialysis regimens. The aim of our study was to quantify the modeling errors and find the methods which give best results. DESIGN: Nonrandomized, repeated measurement, clinical validation study. PATIENTS: The study included 78 patients on continuous ambulatory peritoneal dialysis (PD), daytime ambulatory PD, and automated PD. MEASUREMENTS: We used 207 collections of dialysate and urine associated with peritoneal equilibration tests (PETs) performed with different glucose concentrations (1.36%, 2.27%, 3.86%). The measured urea Kt/V, creatinine clearance (CRCL) and ultrafiltration (UF) were compared with the same data simulated mathematically using the PD ADEQUEST software version 1.4. RESULTS: The Kt/V, CRCL, and UF measured values were significantly correlated and in agreement with modeled data [concordance correlation (rc) was 0.849, 0.839, 0.625 respectively]. The errors (modeled - measured) were: Kt/V = -0.04 +/- 0.27 (p = ns), CRCL = 2.1 +/- 7.7 L (p < 0.001), UF = -121 +/- 711 mL (p = 0.016). Applying ANOVA to both the peritoneal transport data calculated by PD ADEQUEST (mass transfer area coefficient of the solutes, fluid reabsorption, and hydraulic permeability) and the modeling errors, significant differences were found in relation to the PET glucose concentrations. CONCLUSION: PD ADEQUEST proves to be a useful instrument in peritoneal dialysis, although there is undoubtedly still room for improvement in its prediction efficacy, which is influenced by the glucose concentration used in the PET.

Computer Simulation↗
PubMed1999

The relation of the MMPI-2 Pd Harris-Lingoes subscales to psychopathy, psychopathy facets, and antisocial behavior: implications for clinical practice.

Little is known concerning the correlates of the MMPI-2 Psychopathic deviate (Pd) Harris-Lingoes subscales. In four studies with undergraduates, Pd2 (Authority Problems) emerged as the most consistent marker of psychopathy and antisocial behavior and was the only Pd subscale to assess the callousness traditionally associated with psychopathy. Pd3 (Social Imperturbability) correlated highly with social potency and was the only Pd subscale to consistently assess low anxiety proneness. Pd1, Pd4, and Pd5 (Familial Discord, Social Alienation, and Self-Alienation, respectively) correlated highly with externalization of blame but exhibited few differential correlates. Pd2 exhibited statistically significant levels of incremental validity above and beyond all other Pd subscales in the prediction of global psychopathy and antisocial behavior. These findings indicate that several Pd subscales assess markedly different facets of psychopathy and suggest that consideration of different Pd subscale elevations may hold important implications for clinical practice and assessment.

Adolescent↗