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1.
Abstract: Ultrafiltration of water from blood to dialysate decreases the rate of back–diffusion of solutes from dialysate to blood. Therefore, back–clearance ( bK ) of hemodialyzers may be expressed as bK = bK o – bTrQ u , where bK o is the diffusive back–clearance, bTr is the "back–"transmittance coefficient, and Qu is the net ultrafiltration rate. A formula for bK was derived from the one–dimensional theory of hemodialyzer, and bTr was described as a function of bK o and the Staverman reflection coefficient. The transport parameters, bK o and bTr , for creatinine and vitamin B12 were measured in two types of hemodialyzers with negligible back–filtration, using water solutions, and compared with the transport parameters, K o and Tr , for the case of both diffusion and ultrafiltration from blood to dialysate. bK o was in general equal to Ko . bTr was not different from Tr for creatinine whereas bTr was lower than Tr for vitamin B12 . Experimental values of bTr for vitamin B12 were in general agreement with theoretical predictions. However, experimental values of bTr for creatinine were lower than predicted values. We conclude that the impact of ultrafiltration on back–clearance for slowly diffusing solutes is weaker than on their clearance. 相似文献
2.
BORON PIOTR; SOKOLEWICZ-BOBROWSKA ELZBIETA; BORON-KACZMARSKA A.; SIDUN Z.; PILASIEWICZ R. 《Alcohol and alcoholism (Oxford, Oxfordshire)》1986,21(3):281-283
Serological markers of hepatitis B virus infection were studiedin a group of recently presenting alcoholic out-patients andcompared with a group of long-stay in-patients suffering fromchronic alcoholism. All markers of infection were increasedin the chronic group and Were thought to be related to admissionto the Alcohol Unit. Although both groups had normal liver functiontests, the patients with the longer alcohol history had evidenceof two coexisting causes of liver disease and may, therefore,have a much poorer prognosis. 相似文献
3.
HEATHER K. SPENCE LASCHINGER RN PhD PIOTR WILK PhD JULIA CHO RN MScN PAULA GRECO RN MScN 《Journal of nursing management》2009,17(5):636-646
Aims We examined the impact of empowering work conditions on nurses' work engagement and effectiveness, and compared differences among these relationships in new graduates and experienced nurses.
Background As many nurses near retirement, every effort is needed to retain nurses and to ensure that work environments are attractive to new nurses. Experience in the profession and generational differences may affect how important work factors interact to affect work behaviours.
Methods We conducted a secondary analysis of survey data from two studies and compared the pattern of relationships among study variables in two groups: 185 nurses 2 years post-graduation and 294 nurses with more than 2 years of experience.
Results A multi-group SEM analysis indicated a good fit of the hypothesized model. Work engagement significantly mediated the empowerment/effectiveness relationship in both groups, although the impact of engagement on work effectiveness was significantly stronger for experienced nurses.
Conclusions Engagement is an important mechanism by which empowerment affects nurses feelings of effectiveness but less important to new graduates' feelings of work effectiveness than empowerment.
Implications for nursing management Managers must be aware of the role of empowerment in promoting work engagement and effectiveness and differential effects on new graduates and more seasoned nurses. 相似文献
Background As many nurses near retirement, every effort is needed to retain nurses and to ensure that work environments are attractive to new nurses. Experience in the profession and generational differences may affect how important work factors interact to affect work behaviours.
Methods We conducted a secondary analysis of survey data from two studies and compared the pattern of relationships among study variables in two groups: 185 nurses 2 years post-graduation and 294 nurses with more than 2 years of experience.
Results A multi-group SEM analysis indicated a good fit of the hypothesized model. Work engagement significantly mediated the empowerment/effectiveness relationship in both groups, although the impact of engagement on work effectiveness was significantly stronger for experienced nurses.
Conclusions Engagement is an important mechanism by which empowerment affects nurses feelings of effectiveness but less important to new graduates' feelings of work effectiveness than empowerment.
Implications for nursing management Managers must be aware of the role of empowerment in promoting work engagement and effectiveness and differential effects on new graduates and more seasoned nurses. 相似文献
4.
PIOTR KULAKOWSKI MIROSLAW DLUZNIEWSKI SEAN O'NUNAIN A. JOHN CAMM MALGORZATA WARDZYNSKA LESZEK CEREMUZYNSKI 《Pacing and clinical electrophysiology : PACE》1992,15(6):895-904
Transesophageal atrial pacing (TAP) is used in the diagnosis and treatment of paroxysmal narrow QRS complex tachycardia (NQT). The aim of this study was to assess the value of this technique in predicting the efficacy of antiarrhythmic therapy. The study group consisted of 30 consecutive patients with spontaneous NQT whose clinical tachycardia was inducible by TAP. Baseline TAP was performed off all antiarrhythmic medication and repeated during oral antiarrhythmic drug therapy. The pacing protocol consisted of three stages: a single extrastimulus introduced at progressively shorter coupling intervals during sinus rhythm, pacing at incremental rates to the point of second-degree AV block, and bursts of rapid pacing. On repeat stimulation while on oral antiarrhythmic therapy (37 pacing studies) NQT was still inducible in 12 cases. During the follow-up period ten patients developed a recurrence of NQT:nine cases out of 12 (75%), in whom NQT was inducible while on antiarrhythmic therapy, and one case out of 25 (4%), in whom NQT was not inducible (P less than 0.001). The sensitivity of TAP in predicting the outcome of the patients with NQT was 90%, and the specificity 89%. The negative predictive value of TAP (prediction of no recurrence of NQT) was 96%, and the positive predictive value (prediction of recurrence of NQT) was 75%. We conclude that TAP is a simple and accurate method for predicting the efficacy of antiarrhythmic treatment in patients with NQT. 相似文献
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6.
BEATA SREDNIAWA† AGATA MUSIALIK-LYDKA† PIOTR JARSKI† ZBIGNIEW KALARUS† LECH POLONSKI 《Pacing and clinical electrophysiology : PACE》2005,28(S1):S211-S216
The dynamic QT relationship between the QT and RR intervals in normal individuals, including sex differences, has not been well examined. The aim of this Holter monitor-based study was to assess circadian and sex-related variations in QT dynamics in healthy subjects. The study population consisted of 50 healthy volunteers (mean age = 32 ± 6 years, 25 men), in whom 24-hour digital Holter monitoring and QT interactive, beat-by-beat analyses were performed. The mean lengths of QT and RR intervals were measured from the 24-hour recordings. In order to assess QT dynamics, QT/RR linear regression was performed, and the slope was calculated over 24 hour and for day and night periods, and both genders separately. In the whole population, the mean QT interval was 356.5 ± 19.2 ms and RR interval was 785.9 ± 80.7 ms. The mean value of the slope over 24 hour was 0.17 ± 0.03, though significantly steeper during the day (0.13 ± 0.03) than at night (0.09 ± 0.03, P < 0.001). The analysis of QT/RR dynamics over 24 hour revealed a significantly steeper slope in women (0.18 ± 0.03) than in men (0.16 ± 0.03, P = 0.006), as well as during daytime (0.14 ± 0.03 vs 0.12 ± 0.03, P = 0.04). Circadian variations and sex differences were observed in QT dynamics. The latter may explain the greater susceptibility of women to torsades de pointes during treatment with drugs that prolong repolarization. 相似文献
7.
ARTUR PIETRUCHA JERZY MATYSEK WIESAWA PIWOWARSKA DANUTA MROCZEK-CZERNECKA RZEJ GACKOWSKI BOENA STOBIERSKA JADWIGA NESSLER PIOTR MUSIAEK ANTONI DZIATKOWIAK 《Pacing and clinical electrophysiology : PACE》1994,17(11):2064-2067
The aim of our study was to analyze circadian distribution of premature ventricular contractions (PVC) and its coupling interval (CI) in patients after orthotopic heart transplantation (HTx). Forty-two patients (5 females, 37 males) were monitored from 2 weeks to 5 years after HTx; 180 24-hour Holter ECG studies were performed. All recordings were divided into two groups: group I, within 1 month after HTX; and group II, after 1 month. Patients with more than 250 PVC/24 hours were selected for distribution of PVC and CI evaluation. Conclusions : Ventricular arrhythmias occur frequently in patients after heart transplantation. In patients with high Lown scale arrhythmias low occurrence (< 250/24 hours) of PVC was frequently observed (IVa: 81.8%; IVb: 84.7%). Similar patterns of circadian distribution (CD) of PVC and CD of HR in denervated heart after HTx suggest the influence of circulating catecholamines on their occurrence. 相似文献
8.
ROBERT G. MORRIS LUCY J. CURTIS PIOTR ROMANOWSKI JACK D. HARDCASTLE DAVID A. JENKINS MICHAEL ROBINSON ANDREW H. WYLLIE COLIN C. BIRD 《The Journal of pathology》1996,180(4):357-363
Activating mutations in the Ki- ras 2 oncogene are frequently observed in sporadic colorectal adenomas and their incidence is reported to rise in large and tubulovillous adenomas to values close to those in carcinomas. This study shows that this property is a feature of adenomas growing in large bowel that has already demonstrated its propensity to engender malignant tumours: i.e., bowel in which there is a synchronous carcinoma. Adenomas from cancer-free bowel do not share this high incidence of Ki- ras mutations. This difference in mutation incidence between adenomas from cancer-free and cancer-bearing patients does not appear to derive from sampling bias relative to adenoma size, site, or patient age, nor is it found in another gene (APC) known to be of importance in adenoma formation. Large, dysplastic adenomas from cancer-bearing bowel, however, are particularly liable to carry Ki- ras mutations when they arise in patients over 70 years old. The observations suggest that the role of Ki- ras mutations may be more subtle than merely enhancing adenoma growth. Adenoma cells of cancer-prone individuals may suffer more mutational events than those in persons selected as cancer-free. 相似文献
9.
Effect of Therapeutic Ionizing Radiation on Implantable Electronic Devices: Systematic Review and Practical Guidance
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MATEUSZ TAJSTRA M.D. Ph.D. ELZBIETA GADULA‐GACEK M.D. PIOTR BUCHTA M.D. Ph.D. SLAWOMIR BLAMEK M.D. Ph.D. MARIUSZ GASIOR M.D. Ph.D. JEDRZEJ KOSIUK M.D. 《Journal of cardiovascular electrophysiology》2016,27(10):1247-1251
Cardiac implantable electronic devices (CIEDs) have been in use for over 50 years and their therapeutic value is undisputable. With the rapidly aging population, it is estimated that the number of CIEDs will grow dramatically over the next 2 decades. Given these predictions, the topic of management of concomitant conditions associated with older age becomes more relevant than ever. In particular, the number of patients with an implanted CIED diagnosed with cancer is expected to rise by about 70%, from 14 million in 2012 to 22 million within the next 2 decades. Treatment of most of these tumors and tumor metastases requires radiation therapy. However, the necessary high doses of radiation can potentially interact with the function, longevity, and integrity of the CIEDs and/or cause harm to the patient. The impact of an absence of clear therapeutic guidelines for oncology patients with CIEDs who should undergo radiation therapy is vast; and due to the fear of possible complications related to device failure, many of these patients may not be treated adequately to their needs, which can strongly affect their prognosis. This article summarizes the available data on the management of patients with CIEDs undergoing radiotherapy. It systematically presents possible causes and consequences of direct and scattered radiation on CIEDs, highlights possible complications that may occur during this kind of treatment, and provides practical guidance for this challenging real life clinical setting. 相似文献
10.
BERNARD LAMMEK MAGORZATA CZAJA IZABELA DERDOWSKA ELBIETA EMPICKA PIOTR SIKORA WITOLD SZKR
BKA HENRYK I. TRZECIAK 《Chemical biology & drug design》1998,51(2):149-154
In this study we described the synthesis and pharmacological properties of five new analogues of arginine vasopressin (AVP). Four of these analogues contained ethylene-bridged dipeptide Phe-Phe in positions 2 and 3; one had two N-Me-Phe residues. All new peptides were tested for vasopressor and antidiuretic activities. We also estimated the uterotonic activities of these compounds in vitro. Three analogues were highly potent V1-antagonists. One of them, namely [Cpa1,(Phe-Phe)2,3,Val4]AVP, which seemed to not interact with either V2 and oxytocic receptors, was outstandingly selective. It is interesting that the high antipressor potency of our second peptide, [(N-Me-Phe)2,3]AVP, was achieved without modification of position 1. Our results open new possibilities for the design of very potent and selective V1-antagonists of AVP. 相似文献