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J Masín

Publications and source records attributed to J Masín.

6 recordsLinked to original sources
PubMed2005

[Mechanical cardiac support--the first use in Czech Republic].

BACKGROUND: Implantation of mechanical assist device is widely accepted modality of treatment of patients with refractory heart failure. In the present study we evaluated our first one-year experiences with this method for bridging patients to cardiac transplantation. METHODS AND RESULTS: Between April 2003 and May 2004, the Thoratec VAD (Thoratec, Pleasanton, CA, USA) was implanted in 6 patients ( males; age 28-61 years) as a bridge-to-transplant procedure after having received maximum inotropic support and who were at imminent risk of death. In all patients was performed VAD as biventricular device (BiVAD). During a week after placement was observed recovery of organs function in all patients. Five patients survived to heart transplantation. One patient died 21 days after BiVAD placement due to massive bleeding to the respiratory tract. In post-transplantation period 1 patient died second day from acute graft failure and other patient died 34 days after from intracranial bleeding. Three patients has been discharged from the hospital and they are surviving more than I year. CONCLUSIONS: Analysis of our first experiences with the Thoratec BiVAD implantation as bridging to heart transplantation suggests that it is well suited method with respect to long- term prognosis of this group of patients.

Adult↗
PubMed2000

Chaperone activity of tobacco HSP18, a small heat-shock protein, is inhibited by ATP.

NtHSP18P (HSP18), a cytosolic class I small heat-shock protein from tobacco pollen grains, was expressed in Escherichia coli. The viability of these cells was improved by 50% at 50 degrees C, demonstrating its functionality in vivo. Purified recombinant protein formed 240 kDa HSP18 oligomers, irrespective of temperature. These oligomers interacted with the model substrate citrate synthase (CS) to form large complexes in a temperature-dependent manner. Furthermore, HSP18 prevented thermally induced aggregation of CS at 45 degrees C. The fluorescence probe bis-ANS revealed the exposure of HSP18 hydrophobic surfaces at this temperature. Reactivation of chemically denatured CS was also significantly enhanced by HSP18. Surprisingly, HSP18 function was inhibited (in contrast to the related chaperone alphabeta-crystallin and plant sHSPs studied so far) by the presence of ATP in a concentration-dependent manner. The conformational changes of HSP18 imposed by ATP binding were indicated by the difference in the quenching of intrinsic tryptophan fluorescence, and implied more compact structure with ATP. Fluorescence measurements with bis-ANS showed that the conformational shift of HSP18 is suppressed in the presence of ATP. Decreased chaperone activity of HSP18 in the presence of ATP is caused by the lower affinity of conformationally blocked HSP18 for the substrate, as demonstrated by a higher susceptibility of model substrate, malate dehydrogenase, to proteolytic cleavage. Our results suggest that the chaperone activity of some plant sHSPs could be regulated by the availability of ATP in the cytoplasm, which would provide a mechanism to monitor the cell environment, control biological activity of sHSPs, and coordinate it with other ATP-dependent chaperones such as HSP70.

Adenosine Triphosphate↗