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S Zajac

Publications and source records attributed to S Zajac.

At least 19 recordsLinked to original sources
PubMed1999

The cytotoxicity of mafosfamide on G-CSF mobilized hematopoietic progenitors is reduced by SH groups of albumin--implications for further purging strategies.

The efficacy of mafosfamide purging depends on factors like incubation time, drug and erythrocyte concentration. To determine the influence of protein-bound SH groups in the incubation medium, the cytotoxicity of mafosfamide on G-CSF mobilized CD34+/- cells was evaluated by short-term culture assays and drug concentration measurements. 100 micromol/ml mafosfamide was incubated for 30 min in five buffers (PBS, PBS with 1%, 5% and 10% BSA and plasma). The mean calculated areas under the concentration-time curves (AUC) were 2489 +/- 198, 1561 +/- 286, 976 +/- 201, 585 +/- 62 and 605 +/- 196 micromol/l/min. The mean reductions of CFU-GM growth were 79.4%, 73.0%, 62.5%, 30.3%, 6.2% respectively. Similar results were obtained for BFU-E. Regression analysis showed a good correlation between cytotoxicity and AUCs (CFU-GM: r = 0.8195; BFU-E: r = 0.8207). This effect is well explained by the different concentrations of SH moieties in the incubation medium resulting in a higher drug binding capacity. The profound difference between AUCs and CFU-GMs in plasma and 10% BSA cannot be explained by the quantity of SH-groups. It is probably due to an additional enzymatic drug degeneration by the 3'-5'exonuclease subsite of plasma DNA polymerase. In conclusion, the concentration of albumin-associated SH groups strongly influences the cytotoxicity of mafosfamide. It has to be considered as a new and important aspect in ex vivo bone marrow purging.

Albumins↗
PubMed1998

[The natural history study of 208 patients with atherosclerosis of the lower extremities and diabetes mellitus].

Analysis of 208 patients with atherosclerosis of the lower extremities and co-existing diabetes mellitus was performed to document actual symptoms, to propose a classification of extremity ischemic to localisate atherosclerotic changes and to evaluate therapeutic methods and their results. Authors suggest that to improve therapeutic results in this group of patients necessary is as follows: (a) early diagnosis of atherosclerotic ischemia of extremities, (b) proper preparing to revascularization, (c) early reconstruction of ischemic vessels, (d) good specialist controls in after surgery period.

Adult↗
PubMed1997

On the abdominal aortic aneurysms: pulsatile state considerations.

Pulsatile blood flow using incompressible newtonian fluid is investigated numerically in abdominal aortic aneurysm models with the aid of transient Navier-Stokes equations for axisymmetric geometry. The arterial wall is assumed to be rigid. The actual arterial pressure-velocity pulse at the abdominal aorta is used as the inlet boundary condition to the aneurysm. The corresponding velocity at every time-step is assumed to be fully developed parabolic profile at the inlet. Time-dependent formation of vortices and occurrence of stagnation zones are analyzed in this numerical study. It has been found that the distal end of the aneurysm is subjected to maximum shear stress and pressure during the entire cycle. This analysis also confirms that the mechanical forces on the arterial wall, developed by the blood flow which is pulsatile in nature, may play an important role in both development and growth of aneurysms. It has also been found that a quasi-steady state may be used to explain sufficiently the basic flow characteristic within the aneurysm. The wall shear stress in the quasi-steady state at the distal end of the aneurysm during the most adverse condition was approximately the same as in the pulsatile state for a similar situation.

Aorta, Abdominal↗
PubMed1996

[A study of natural history in 208 patients with atherosclerosis of lower limb arteries and diabetes mellitus].

In the recent years a constant increase of the number of surgical patients with associated diabetes mellitus is observed. Surgical risk is still higher and therapeutic results are worse than in patients without diabetes mellitus. Many years of experience of our department in the surgical treatment of lower limb atherosclerosis (A0) in patients with diabetes, and also the previously published results of studies make possible drawing of conclusions and formulating of a general view. The studies were carried out in 208 patients with A0 and diabetes mellitus. On admission, 65.9% of the patients had IV degrees of limb ischaemia according to Fontaine. Vascular operations in these patients accounted only for 25% of all operations and were performed in 37% of patients. Amputations accounted even for 53.7% of all operations, and among them major amputations accounted for 56.3%. The early and remote results of the operations carried out were subjected to statistical analysis and presented using cumulated indices.

Adult↗
PubMed1992

On the subclavian steal syndrome in vitro studies.

An elastic model of the arterial system has been used in which a specially designed pumping unit simulated the heart action. Physiological pressures and normal geometry, size, and flow distribution together with the normal cardiac output and use of prosthetic heart valves are the features of the system. Atherosclerosis was simulated by introducing blockages of known cross-section at specific sites of predilection. It has been shown that, for some specific occlusion magnitude in the left or right subclavian, or in the brachycephalic arteries, the stagnant no blood flow condition will appear in the left vertebral, or the right vertebral, or right common carotid, or the right internal carotid arteries. For larger occlusions the blood flow in these arteries reverses its direction, i.e., the "steal syndrome" appears. It is shown that besides the known single steal syndrome there exists also a double steal syndrome, i.e., blood reverses its flow direction simultaneously in two arteries, both on the right side of the arterial system. This blood is taken from the circle of Willis, which at the same time is significantly supplemented by the increased blood flow through the other arteries leading into the circle of Willis.

Arteriosclerosis↗
PubMed1988

Recurrences after surgical treatment of patients with post-thrombotic syndrome of the lower extremities.

A Linton flap operation was performed in 148 patients with post-thrombotic syndrome of the lower extremities. One-hundred and five patients were followed up from 6 months to 10 years and 14.5% of cases had recurrent ulcers. The most common causes of recurrence was further deep venous thrombosis or remaining incompetent perforating veins. All patients with a recurrence of their ulcer had a further operation and incompetent perforating veins were ligated and divided with good clinical results.

Female↗
PubMed1976

Effect of ischemic anoxia on electrical and mechanical activity of the totally isolated porcine stomach.

Electrical and mechanical activity were recorded from totally isolated whole porcine stomachs perfused with homologous blood. Stagnant, complete ischemia was then produced by closing the gastric artery and vein for various periods of time up to 3 h. After a given period of ischemia, blood was recirculated for 10 min and then pentagastrin was injected into the gastric artery. The vagus nerve was also electrically stimulated at various stages of anoxia and recirculation. After up to 90 min of ischemia, stomachs were able to demonstrate electrical control activity of low frequency after 10 min of blood recirculation. After injection of pentagastrin, electrical control activity rapidly became normal. When ischemia lasted 120 min or longer, recirculation of blood did not induce reappearance of electrical control activity, but pentagastrin injection produced a normal response. After ischemia of 240 min duration or longer, recirculation and pentagastrin had no effect. In previously ischemic stomachs the response to vagal stimulation occurred only in the stomachs responding to pentagastrin.

Animals↗