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51.
PV Romero B Rodriguez J Lopez-Aguilar F Manresa 《Canadian Metallurgical Quarterly》1998,84(3):1040-1047
To investigate whether changes of tissue resistance (Rti) during methacholine (MCh)-induced constriction correspond to an intrinsic mechanism or are an artifact of increased airways inhomogeneity, rabbits were studied after exposure to air (n = 7) or 1.5 parts/million O3 (n = 6). Animals were anesthetized and mechanically ventilated. Tracheal flow and pressure (Ptr) and four alveolar capsule pressures (Pcap) were measured during 3 min after administration of an intrajugular bolus of 0.8 mg/ml MCh. By adjustment of the equation of motion [P(t) = E . V(t) + R . dV(t)/dt + P0] [where P(t), V(t), and dV(t)/dt are pressure, volume, and flow as a function of time, respectively, E is elastance, R is resistance, and P0 is end-expiratory pressure] to Ptr, lung resistance (RL) and dynamic elastance (EL) were determined breath by breath. Rti and airways resistance (Raw) were determined from Pcap in phase with rate of change of pulmonary expansion. Hysteresivity (eta) was calculated. Parallel inhomogeneity was estimated from the coefficients of variation (CV) of every Pcap at end inspiration and end expiration. Increase in CV significantly lagged Rti, RL, and eta. A linear relationship between EL and Raw was observed. Our results suggest that changes in tissue mechanics during the transition to the constricted state are not artifactual. 相似文献
52.
HJ Lenz KD Danenberg CG Leichman B Florentine PG Johnston S Groshen L Zhou YP Xiong PV Danenberg LP Leichman 《Canadian Metallurgical Quarterly》1998,4(5):1227-1234
We initiated a retrospective study to determine whether p53 status and thymidylate synthase (TS) protein expression in primary colon tumors influence recurrence and survival for patients with stage II colon cancer. Tumor specimens from 45 consecutive untreated patients with stage II colon cancer were examined for p53 and TS protein expression using immunohistochemistry. The median follow-up was 5.1 years. Eighteen patients had left-sided tumors, and 27 had right-sided tumors. Fourteen of 45 patients (31%) developed recurrence. p53 overexpression was detected in the tumors of 18 patients (40%); 10 patients (55%) with p53 overexpression recurred; and 4 of 27 (15%) without evidence of p53 overexpression recurred (P = 0.002). High TS expression was detected in the tumors of 16 patients (36%): 8 patients (50%) with high TS expression recurred, and 6 patients (21%) with low TS expression recurred (P = 0.027). Patients with p53 overexpression had a significantly poorer survival than did those patients without p53 overexpression (P < 0.001). High TS expression was associated with poor survival (P = 0.004). p53 overexpression and high TS expression were significantly associated with left-sided tumors (P = 0.003 and P = 0.022). Thirteen of 16 patients (81%) with high TS expression also overexpressed p53, and 24 of 29 patients (81%) with low TS expression did not manifest p53 overexpression (P < 0.001). p53 and TS expression in primary stage II colon cancer are associated and appear to influence recurrence and survival. In this pilot study, left-sided tumors demonstrate significantly more p53 overexpression and significantly higher TS expression than do right-sided tumors, which may explain the significantly poorer survival for patients with left-sided tumors. 相似文献
53.
PV Sulochana J Mathai S Sathyabhama P Augustine 《Canadian Metallurgical Quarterly》1998,41(4):495-498
The purpose of this study was to determine whether there are changes in anterior and posterior glenohumeral translation after arthroscopic, nonablative, thermal capsuloplasty with a laser. Two anteriorly and two posteriorly directed loads were sequentially applied to the humerus of nine cadaveric glenohumeral joints, and anterior and posterior translation of the humerus on the glenoid was measured. The glenoid was rigidly fixed, and the glenohumeral joint was positioned simulating 90 degrees of shoulder abduction and 90 degrees of external rotation. Using the holmium:yttrium-aluminum-garnet laser, thermal energy was then applied to the anterior capsuloligamentous structures and anterior and posterior translation measurements were then repeated. The results showed a significant reduction in anterior and posterior translation after laser anterior capsuloplasty. Anterior translation decreased from 10.9 +/- 2.0 mm (mean +/- SEM) to 6.4 +/- 1.5 mm with the 15-N load; and from 13.4 +/- 2.1 mm to 8.9 +/- 1.8 mm with the 20-N load. Posterior translation decreased from 7.2 +/- 1.2 mm to 4.4 +/- 0.6 mm with the 15-N load and from 10.4 +/- 1.4 mm to 6.5 +/- 0.9 mm with the 20-N load. These results indicate that the holmium:yttrium-aluminum-garnet laser can be used to decrease glenohumeral joint translation and may be an effective treatment for glenohumeral joint instability. 相似文献
54.
PV LoGrasso J Hawkins LJ Frank D Wisniewski A Marcy 《Canadian Metallurgical Quarterly》1996,93(22):12165-12170
There is a growing body of evidence, including data from human genetic and T-cell receptor function studies, which implicate a zeta-associated protein of M(r) 70,000 (Zap-70) as a critical protein tyrosine kinase in T-cell activation and development. During T-cell activation, Zap-70 becomes associated via its src homology type 2 (SH2) domains with tyrosine-phosphorylated immune-receptor tyrosine activating motif (ITAM) sequences in the cytoplasmic zeta chain of the T-cell receptor. An intriguing conundrum is how Zap-70 is catalytically activated for downstream phosphorylation events. To address this question, we have used purified Zap-70, tyrosine phosphorylated glutathione S-transferase (GST)-Zeta, and GST-Zeta-1 cytoplasmic domains, and various forms of ITAM-containing peptides to see what effect binding of zeta had upon Zap-70 tyrosine kinase activity. The catalytic activity of Zap-70 with respect to autophosphorylation increased approximately 5-fold in the presence of 125 nM phosphorylated GST-Zeta or GST-Zeta-1 cytoplasmic domain. A 20-fold activity increase was observed for phosphorylation of an exogenous substrate. Both activity increases showed a GST-Zeta concentration dependence. The increase in activity was not produced with nonphosphorylated GST-Zeta, phosphorylated zeta, or phosphorylated ITAM-containing peptides. The increase in Zap-70 activity was SH2 mediated and was inhibited by phenylphosphate, Zap-70 SH2, and an antibody specific for Zap-70 SH2 domains. Since GST-Zeta and GST-Zeta-1 exist as dimers, the data suggest Zap-70 is activated upon binding a dimeric form of phosphorylated zeta and not by peptide fragments containing a single phosphorylated ITAM. Taken together, these data indicate that the catalytic activity of Zap-70 is most likely activated by a trans-phosphorylation mechanism. 相似文献
55.
MK Sly MD Prager J Li FB Harris P Shastri R Bhujle R Chao PV Kulkarni A Constantinescu ME Jessen RC Eberhart 《Canadian Metallurgical Quarterly》1996,42(5):M494-M499
The authors used quantitative gamma scintigraphy to evaluate the influence of nitric oxide gas on platelet and neutrophil deposition in Cobe Duo microporous oxygenators during cardiopulmonary bypass (CPB). The effects of nitric oxide gas on circulating platelet and neutrophil counts and platelet function also were assessed. Animals were prepared by standard methods. Cells were harvested, labeled (111 In platelet and 99mTc neutrophil), infused, and recirculated. Nitric oxide gas, a guanylate cyclase pathway promoter, was infused int he Duo gas port at 500 ppm (t = 0-60 min), increased to 1,000 (t = 60-80 min), and stopped (final, 10 min). Images were taken at 10-15 min intervals during CPB. Standard isotope image corrections were made. No differences between nitric oxide gas and control experiments were observed for flow, pressure, hematocrit, or replacement volume. Nitric oxide gas infusion significantly (p < 0.05) reduced both platelet adherence to the oxygenator and in vitro platelet aggregation. Neutrophil adhesion tended to be lower, and circulating platelet and neutrophil counts tended to be higher with nitric oxide gas infusion. Results of in vitro aggregometry studies using rabbit platelets indicate that the class V phosphodiesterase inhibitor zaprinast can strongly enhance the inhibitory effects of nitric oxide. The authors conclude nitric oxide gas is a promising platelet sparing agent in the setting of CPB. 相似文献
56.
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58.
OV Gerasimenko JV Gerasimenko PV Belan OH Petersen 《Canadian Metallurgical Quarterly》1996,84(3):473-480
In pancreatic acinar cells low (physiological) agonist concentrations evoke cytosolic Ca2+ spikes specifically in the apical secretory pole that contains a high density of secretory (zymogen) granules (ZGs). Inositol 1,4,5-trisphosphate (IP3) is believed to release Ca2+ from the endoplasmic reticulum, but we have now tested whether the Ca(2+)-releasing messengers IP3 and cyclic ADP-ribose (cADPr) can liberate Ca2+ from AGs. In experiments on single isolated ZGs, we show using confocal microscopy that IP3 and cADPr evoke a marked decrease in the free intragranular Ca2+ concentration. Using a novel high resolution method, we have measured changes in the Ca2+ concentration in the vicinity of an isolated AG and show that IP3 and cADPr cause rapid Ca2+ release from the granule, explaining the agonist-evoked cytosolic Ca2+ rise in the secretory pole. 相似文献
59.
Two series of mono- and dysfunctional aniline mustards linked to a bisbenzimidazole minor groove binder have been prepared using a new method (polyphosphate ester-mediated direct coupling of appropriate mustard acids with a preformed advanced phenylenediamine intermediate). As the linker chain attaching the mustard was lengthened the binding site size of the compounds to calf thymus DNA remained essentially constant at 2.6 nucleotides, but reversible binding strength declined by a factor of 2. Analogues with longer linker chains alkylated DNA much more rapidly than those with shorter chains, consistent with the electronic factors. The short chain analogues also failed to alkylate a 120 bp HindIII to Bg/II fragment of the gpt gene, as measured by gel electrophoresis cleavage assays. The longer chain analogues (both mono- and dysfunctional mustards) showed patterns of DNA alkylation that varied with chain length. In particular, while most compounds showed substantial N7 alkylation at many guanine residues, the analogue with a (CH2)3 linker chain showed strong alkylation at adenine sites in poly-AT regions. For the longer chain analogues, the bifunctional mustards were substantially (10- to 20-fold) more cytotoxic than the corresponding monofunctional analogues. 相似文献
60.