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J Nozynski

Publications and source records attributed to J Nozynski.

8 recordsLinked to original sources
PubMed2006

Atomic force microscopy and FT-IR spectroscopy investigations of human heart valves.

Human aortic, mitral, tricuspid and pulmonary heart valves were investigated by the contact mode atomic force microscopy (AFM) in air, and using FT-IR spectroscopy in the frequency range 950-4000 cm(-1). Heart valves were collected post mortem from 65-78 years old patients who died from non-cardiac diseases. All of the examined valves showed considerable heterogeneity in the surface topography of collagen fibrils as well as in their organization on the tissue surface. The AFM images revealed areas with significantly different spatial organization of the collagen fibril bundles. We observed zones with multidirectional, stacked collagen fibrils as well as areas of thin fibrils packed regularly, densely and "in phase". The majority of the collagen fibrils reproduced the typical transverse D-banding pattern, with the band interval varying in rather wide range of 70-90 nm. Using AFM imaging, objects that correspond to some pathological states of heart valves at their early stages, i.e. some forms of mineral deposits, were observed. The FT-IR spectra allowed us to recognize main components, i.e. collagen and elastin, in di.erent layers (ventricularis, fibrosa) of the valve leaflets as well as they gave also support for the presence of mineral deposits on the valve surface. The presented results showed, that the AFM imaging and FT-IR spectroscopy can be applied as a complementary methods for structural characterization of heart valves at the molecular and supramolecular levels.

Aged↗
PubMed2005

Structural changes in pericardium tissue modified with tannic acid.

INTRODUCTION: Structural modification of proteins, mainly collagen in connective tissues, is important in the manufacture of tissue-derived biomaterials. Natural compounds like genipin or tannic acid (TA) have been proposed instead of glutaraldehyde which shows cytotoxic effects on the processed tissue. Furthermore, calcification of glutaraldehyde-treated tissue limits the functional lifetime of bioprostheses. TA is known to form numerous hydrogen bonds with proteins. The purpose of our study was to investigate structural changes in porcine pericardium upon chemical modification with tannic acid. METHODS: Porcine pericardium tissue (PP) was soaked in 2% TA for 4, 24 or 48 hours. Changes in tissue structure were studied using electrophoresis (SDS-PAGE) and histological examination. Structural stability of PP tissue was evaluated by SDS/NaCl extraction method and enzymatic digestion with pancreatin. RESULTS: TA-modification of PP caused a time-dependent decrease in the number of peptides extracted from tissue. Microscopic studies revealed no significant morphological differences between native and TA-modified tissues, except for the native pancreatin-digested tissue where lack of both cells and low molecular peptides was observed. CONCLUSION: Modification of PP with TA causes the structural changes leading to an increase in the tissue resistance to SDS/NaCl extraction and enzymatic digestion, providing experimental evidence for the higher structural stability of TA-treated tissue.

Animals↗
PubMed2003

Pathologic assessment of cardiomyocytes in heart transplant recipients treated with rapamycin or cyclosporine.

The aim of this study was to compare cardiomyocytes and stromal pathology in heart transplant recipients treated with rapamycin (RAPA) versus cyclosporine (CyA). We analyzed elective biopsies obtained during first 3 months after heart transplantation in four patients treated with RAPA (24 biopsies) and seven patients receiving CyA (49 biopsies). Additional medications in both groups consisted of mycophenolate mofetil or azathioprine and prednisone. The intensity of rejection was assessed using the ISHLT scale; it was comparable in both groups based upon the number of results showing significant rejection and the average biopsy scores. Each slide was also examined under high-power magnification to sarcoplasmic and nuclear changes. Sarcoplasmic vacuolation, premyocytolysis and myocytolysis, nuclear staining, stromal fibrosis and edema, presence of vasculopathy, and lymphocytes infiltrating the myocardium occurred more frequently in the CyA group. The difference in the degree of hyperchromasia of the nuclei was highly significant (67% versus 10%, P <.00001). Our findings suggest that despite comparable levels of rejection as assessed using the ISHLT scale, patients treated with RAPA display fewer signs of cardiomyocytic alterations early after heart transplantation.

Biopsy↗
PubMed2003

Deterioration of renal function after replacement of cyclosporine with sirolimus in five patients with severe renal impairment late after heart transplantation.

A retrospective analysis of all cases when cyclosporine (CyA) was replaced with sirolimus (SIR) to avoid the renal toxicity of CyA late after heart transplant (OHT) was discontinued due to advanced renal impairment in all five heart transplant recipients (four men, 1 women; age 41 years, range 38-45; time after OHT 5 years, range 4-14). The serum creatinine level at the time of SIR introduction, which was 298 micromol/L (range 217-676), had remained stable for the 6 months prior to conversion. Target SIR trough levels were 12-20 ng/mL. In four patients the last dose of CyA was immediately followed by the first dose of SIR, whereas in one patient CyA was tapered gradually in the presence of low-dose SIR. Deterioration of renal function with signs of fluid overload and increased serum creatinine levels (Delta: 77, 33-150 micromol/L) was observed in all patients. Two patients required dialysis during SIR treatment including one case of pulmonary edema requiring emergency hemodialysis. None of four biopsies showed significant rejection. Four patients were converted back to low-dose CyA (including the two patients requiring dialysis during SIR therapy); one was maintained on mycophenolate mofetil. The creatinine level at the time of SIR discontinuation was (range 250-753) micromol/L, 448. Eventually, all patients required dialysis. In conclusion, replacement of cyclosporine with sirolimus in heart transplant recipients with severe renal impairment late after transplantation may accelerate renal failure.

Adult↗
PubMedDate not supplied

Nuclear mean gray level and chromatin distribution changes in cardiomyocytes of heart transplant recipients suffering from acute cellular rejection.

BACKGROUND: Distribution and staining of the nuclear chromatin are sensitive indicators of changes in physiology and pathology of cells. However, their use in heart transplant recipients is rare. The aim of this study was to compare cardiomyocyte status in heart transplant recipients suffering from moderate acute cellular rejection and subjects without signs of active cellular rejection. MATERIALS AND METHODS: One hundred twenty-nine endomyocardial biopsy samples from 43 heart transplant recipients (no later than 6 months after surgery) were evaluated. Overall, 3235 cardiomyocytic nuclei were analyzed using the Quantimet image analysis system to assess the mean gray level: 1584 nuclei were found in biopsies without signs of rejection or with nonsignificant rejection (ISHLT grades 0, 1A, and 1B), whereas the remaining 1651 nuclei were measured from biopsies showing ISHLT grade 3A (significant rejection). Additionally, the chromatin distribution was assessed in all eligible nuclei. RESULTS: The mean gray level was markedly increased in nuclei from biopsy samples with significant rejection (182.6 vs 112.5, P < .001, Mann-Whitney U test). Moreover, the analysis of chromatin distribution revealed significantly more frequent chromatin marginalization and irregular distribution in rejecting subjects (P < .001, chi-square test). CONCLUSION: Inflammatory stimulation of cardiomyocytes during acute cellular rejection of the transplanted heart influences the chromatin distribution in the nuclei, which may have an additional value, when assessing the severity of rejection.

Acute Disease↗