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11.
The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment. The efficacy of the machine was tested by contaminating a standard set of instruments with different organisms and using a filtration method to assess recovery of organisms from the wash fluids of instruments post-sterilization. Experiments were performed under clean (the organism only) and dirty (organism mixed with egg protein) conditions. A parallel study conducted using a 3M STERIVAC ethylene oxide sterilizer could not be completed owing to closure of the ethylene oxide plant. For sterilization of instruments with long and narrow lumens, hydrogen peroxide adaptors are necessary. The STERRAD 100 sterilizer can achieve effective sterilization of heat labile instruments with a reduction of 6 log10 cfu/mL of organisms tested. This method has the advantages over ethylene oxide sterilization of safety, ease of maintenance and no requirement for aeration time. 相似文献
12.
MS Kurian RS de la Cuesta GL Waneck DT MacLaughlin TF Manganaro PK Donahoe 《Canadian Metallurgical Quarterly》1995,1(3):343-349
Müllerian inhibiting substance (MIS), an inhibitor of growth and development of the female reproductive ducts in male fetuses, requires precise proteolytic cleavage to yield its biologically active species. Human plasmin is now used to cleave and, thereby, activate immunoaffinity-purified recombinant human MIS at its monobasic arginine-serine site at residues 427-428. To avoid the need for exogenous enzymatic cleavage and to simplify purification, we created an arginine-arginine dibasic cleavage site (MIS RR) using site-directed mutagenesis to change the serine at position 428 (AGC) to an arginine (cGC). The mutant cDNA was then stably transfected into a MIS-responsive ocular melanoma cell line, OM431, followed by cloning for amplified expression to test its biological activity in vitro and in vivo. Media from each clone were assayed for production of MIS RR by a sensitive ELISA for holo-MIS, and high- and low-producing clones were selected for further study. Media from the highest MIS RR producer caused Müllerian duct regression in an organ culture bioassay. Other transfections were done with an empty vector (pcDNAI Neo) or a construct lacking the leader sequence and thus failing to secrete MIS, to serve as controls. The OM431 clones containing the MIS RR mutant were growth inhibited in monolayer culture. The high- and low-producing MIS RR OM431 clones, along with transfected OM431 controls, were injected into the tail veins of immunosuppressed severe combined immunodeficiency mice for in vivo analyses. Four to 6 weeks later, pulmonary metastases were counted in uniformly inflated lungs. OM431 clones containing the more easily cleaved MIS RR displayed a significant dose-dependent reduction in pulmonary metastases when compared to the lungs of animals given injections of OM431 clones containing empty vector, leaderless MIS, or wild-type MIS that requires activation by plasmin cleavage. Since the purification protocol of MIS RR is less complicated than that for wild-type MIS, which requires subsequent enzymatic activation, MIS RR can be used for scale-up production with increased yields for further therapeutic trials against MIS-sensitive tumors. 相似文献
13.
GW Lambert DM Kaye HS Cox M Vaz AG Turner GL Jennings MD Esler 《Canadian Metallurgical Quarterly》1995,57(3):255-267
Veno-arterial plasma concentration differences and regional organ plasma flows were used to quantify the relative amounts of 5-hydroxyindoleacetic acid (5-HIAA) contributed by various sites into the peripheral circulation. Positive venoarterial concentration gradients were found in the hepatosplanchnic, forearm, cardiac and jugular vessels in the healthy subjects. The renal circulation was determined to be the principal site of 5-HIAA clearance, extracting 18 +/- 2 nmol/min. The gut was the greatest contributor to the total 5-HIAA plasma pool with the relative contributions of the various organs being as follows: hepatosplanchnic organs 58%, skeletal muscle 26%, brain 6% and the heart 3%. The source of 5-HIAA stemming from these regional beds remains unknown, it may derive from serotonin taken up by and deaminated in ubiquitous endothelial cells, enterochromaffin cells of the gut, peripheral serotonergic nerves, serotonin turnover in platelets or perhaps the metabolism of serotonin taken up by sympathetic nerves. To test the latter hypothesis we examined 23 patients with chronic congestive heart failure and 9 patients with pure autonomic failure to investigate the possible effects of sympathetic nervous system overactivity and underactivity on peripheral 5-HIAA production and plasma 5-HIAA concentration. The resting arterial plasma 5-HIAA concentration in the heart failure patients was increased three-fold. This elevated plasma 5-HIAA concentration was attributable to an increased rate of whole body 5-HIAA production. The arterial 5-HIAA plasma concentration in the autonomic failure patients was paradoxically elevated, being 70% greater than that of the healthy subjects. The increased 5-HIAA plasma concentration in these patients was accounted for by a reduction in 5-HIAA plasma clearance. In all subjects studied there was a weak relationship only between total body norepinephrine spillover to plasma and the arterial 5-HIAA plasma concentration. We found that in healthy subjects the overflow of 5-HIAA into the hepatic vein was significantly related to the underlying degree of sympathetic activity. It can be concluded that 5-HIAA is produced at a number of sites throughout the body with the arterial plasma concentration being dependent on both the level of production and plasma clearance. By far the majority of 5-HIAA in plasma is derived from the gut with only minimal contribution from the brain. 相似文献
14.
Recently some heat-shock proteins have been linked to functionsof chaperoning protein folding in vivo. Here currentexperimental evidence is reviewed and possible requirementsfor such an activity are discussed. It is proposed that onemode of chaperone action is to actively unfold misfolded orbadly aggregated proteins to a conformation from whkh they couldrefold spontaneously; that improperly folded proteins are recognizedby excessive stretches of solvent-exposed backbone, rather thanby exposed hydrophobic patches; and that the molecular mechanismfor unfolding is either repeated binding and dissociation (plucking)or translocation of the protein backbone through a binding cleft(threading), allowing the threaded chain to refoldspontaneously. The observed hydrolysis of ATP would providethe energy for active unfolding. These hypotheses can be appliedto both monomeric folding and oligomeric assembly and are sufficientlydetailed to be open to directed experimental verification. 相似文献
15.
F Gonzalez RL Walton B Shafer WE Matory GL Borah 《Canadian Metallurgical Quarterly》1993,91(7):1270-1276
The condition macromastia has not been defined and characterized precisely by the medical community. Whether the patient with hypertrophic breasts is a candidate for or can be helped by reduction mammaplasty is unclear to both the medical and the lay community. A prospective study of 39 women undergoing reduction mammaplasty surgery was initiated to answer these questions. Patients rated the severity of their somatic pain symptoms and discomfort before reduction mammaplasty and again after complete recovery. The severity of their symptoms and complaints was numerically graded and analyzed. These data were compared with similar data obtained from 40 "small-breasted" women of similar age. Headache, neck pain, back pain, shoulder pain, and bra strap groove pain were present in 60 to 92 percent of patients, and 97 percent of patients had at least three of these pain symptoms preoperatively. All the patients had reduction of their pain symptomatology postoperative, and 25 percent of the study patients had total elimination of pain symptoms by reduction mammaplasty. The postoperative incidence and severity of pain symptoms and discomfort complaints were statistically equivalent to or less than the levels in the control group. 相似文献
16.
17.
Ion beam enhanced deposition (IBED) was adopted to synthesize biocompatible titanium oxide film. Structure characteristics of titanium oxide film were investigated by RBS, AES, and XRD. The blood compatibility of the titanium oxide film was studied by measurements of blood clotting time and platelet adhesion. The results show that the anticoagulation property of titanium oxide film is improved significantly. The mechanism of anticoagulation of the titanium oxide film was discussed. 相似文献
18.
Atherogenic effect of oxidized products of cholesterol 总被引:4,自引:0,他引:4
Cholesterol under certain in vitro and possibly in vivo conditions may be oxidized to oxysterols, which are suspected of being initiators of atherosclerotic plaques. Oxysterols inhibit HMG-CoA reductase activity resulting in a decreased cholesterol concentration in the cell membrane, which leads to endothelial membrane injury and probable premature cell death. Exogenous oxidation of cholesterol in human tissues under certain unusual conditions is highly probable. Dietary oxysterols are absorbed in the gastrointestinal tract and are selectively transported by the athrogenic lipoproteins LDL and VLDL. The oxysterols cholestanetriol and 25-OH cholesterol have been shown to be atherogenic. Oxysterols are commonly found in dried egg products, powdered milk, cheeses and in a variety of high temperature dried animal products. 相似文献
19.
Hamp M.J. Wright J. Hubbard M. Brimacombe B. 《Photonics Technology Letters, IEEE》2002,14(11):1524-1526
The change in the chromatic dispersion of optical fiber with temperature is an important design parameter for 40-Gb/s systems. We derive an equation for the change in dispersion with a temperature that is more general than what has previously been published. We present experimental results for the change in fiber dispersion with temperature for six commercially available fiber types of interest for 40-Gb/s communication systems. In addition, we demonstrate that the empirical model developed by Ghosh et al in 1994 for the temperature-dependent index of refraction of SiO2 can be used to accurately model the temperature dependence of the chromatic dispersion of a wide variety of optical fibers 相似文献
20.
Green R.P.M. Crofts G.J. Hubbard W. Udaiyan D. Dong Hwan Kim Damzen M.J. 《Quantum Electronics, IEEE Journal of》1996,32(3):371-377
We demonstrate that self-induced gain gratings can provide nonlinear optical feedback that results in single frequency selection and passive self Q-switching of a conventional linear laser cavity. An experimental Nd:YAG laser system is described that yields a temporally-smooth 20 ns pulse at 1.064 μm. In addition, we show that the feedback has phase-conjugate properties that permit “flower-like” mode formation even though the azimuthal symmetry of the cavity is broken 相似文献