Search PubMed⌕ Search

Biomedical subjects

P Szenohradszky

Publications and source records attributed to P Szenohradszky.

At least 19 recordsLinked to original sources
PubMed2005

Peritubular capillary damage in acute humoral rejection: an ultrastructural study on human renal allografts.

The ultrastructural features of peritubular capillary (PC) damage was studied in 12 kidney allografts with acute humoral rejection (AHR). AHR manifested in diffuse linear PC staining for C4d, and histology consistent with Banff grade III in 7 recipients and Banff grade II in 5. Allografts with acute tubular necrosis served as controls. First biopsies (post-transplantation day 16.2 +/- 2.2): The intra-capillary exudate comprised monocytes (59%), polymorphonuclears (14%), lymphocytes (12%) and not otherwise specified mononuclears (15%). Three patterns of focal PC endothelial injury were observed: lysis, an increased rate of apoptosis and fragmentation. No correlation was found between the respective damage types and the inflammatory cell types or the Banff grades. Controls revealed endothelial swelling, detachment from basement membrane and fragmentation. Follow-up biopsies: Monocytes transformed into macrophages intra-luminally. The reparative changes comprised endothelial cytoplasmic protrusions, binucleated endothelial cells and capillary sprouts. Early transplant capillaropathy and transplant glomerulopathy were noted in 2 recipients. Literature data indicate that lysis is mediated by anti-HLA alloantibodies; apoptosis, demonstrated first in the present study, may be induced by non-HLA-type anti-endothelial antibodies. Fragmentation is caused by ischemia. Ongoing endothelial injury leads to transplant capillaropathy and transplant glomerulopathy, the characteristic lesions of chronic rejection.

Acute Disease↗
PubMed2002

The cellular electrophysiologic effect of a new amiodarone like antiarrhythmic drug GYKI 16638 in undiseased human ventricular muscle: comparison with sotalol and mexiletine.

The cellular electrophysiologic effect of GYKI 16638, a new antiarrhythmic compound was studied and compared with that of sotalol and mexiletine in undiseased human right ventricular muscle preparation by applying the conventional microelectrode technique. GYKI 16638 (5 microM), at stimulation cycle length of 1000 ms, lengthened action potential duration (APD(90)) from 338.9 +/- 28.6 ms to 385.4 +/- 24 ms (n = 9, p > 0.05). This APD lengthening effect, unlike that of sotalol (30 microM), was rate-independent. GYKI 16638, contrary to sotalol and like mexiletine (10 microM), exerted a use-dependent depression of the maximal rate of depolarization (V(max)) which amounted to 36.4 +/- 11.7% at cycle length of 400 ms (n = 5, p < 0.05) and was characterised with an offset kinetical time constant of 298.6 +/- 70.2 ms. It was concluded that GYKI 16638 in human ventricular muscle shows combined Class IB and Class III antiarrhythmic properties, resembling the electrophysiological manifestation seen after chronic amiodarone treatment.

Action Potentials↗
PubMed2001

The slow component of the delayed rectifier potassium current in undiseased human ventricular myocytes.

OBJECTIVE: The purpose of this study was to investigate the properties of the slow component of the delayed rectifier potassium current (I(Ks)) in myocytes isolated from undiseased human left ventricles. METHODS: The whole-cell configuration of the patch-clamp technique was applied in 58 left ventricular myocytes from 15 hearts at 37 degrees C. Nisoldipine (1 microM) was used to block inward calcium current (I(Ca)) and E-4031 (1-5 microM) was applied to inhibit the rapid component of the delayed rectifier potassium current (I(Kr)). RESULTS: In 31 myocytes, an E-4031 insensitive, but L-735,821 and chromanol 293B sensitive, tail current was identified which was attributed to the slow component of I(K) (I(Ks)). Activation of I(Ks) was slow (tau=903+/-101 ms at 50 mV, n=14), but deactivation of the current was relatively rapid (tau=122.4+/-11.7 ms at -40 mV, n=19). The activation of I(Ks) was voltage independent but its deactivation showed clear voltage dependence. The deactivation was faster at negative voltages (about 100 ms at -50 mV) and slower at depolarized potentials (about 300 ms at 0 mV). In six cells, the reversal potential was -81.6+/-2.8 mV on an average which is close to the K(+) equilibrium potential suggesting K(+) as the main charge carrier. CONCLUSION: In undiseased human ventricular myocytes, I(Ks) exhibits slow activation and fast deactivation kinetics. Therefore, in humans I(Ks) differs from that reported in guinea pig, and it best resembles I(Ks) described in dog and rabbit ventricular myocytes.

Adult↗
PubMed2001

The value of electron microscopy in the diagnosis of chronic renal allograft rejection.

The main causes of the late dysfunction of renal allografts are chronic rejection and chronic transplant nephropathy. Both are clinicopathologic entities, with a similar clinical presentation, but different histologic appearances. Chronic rejection is characterized by the presence of alloantigen-induced lesions (transplant arteriopathy and transplant glomerulopathy), and chronic transplant nephropathy by nonspecific sclerosing changes. The incidence of transplant arteriopathy and transplant glomerulopathy is relatively low. Electron microscopy (EM) may overcome the limitations in the histologic diagnosis of chronic rejection, because it verifies alloantigen-induced chronic microvasculopathy in the peritubular capillaries (transplant capillaropathy), and identifies transplant glomerulopathy more precisely than does light microscopy. To assess the value of EM in chronic rejection diagnosis, a retrospective search for transplant capillaropathy and transplant glomerulopathy was performed in a consecutive series of 91 biopsies performed > or = 6 months after implantation (median: 26 months, range 6-186) and the diagnoses were reclassified on the basis of the ultrastructural findings. The definitions used were: transplant capillaropathy: a peritubular capillary profile with seven or more circumferential basement membrane layers, or at least three profiles with five or six circumferential layers; ultrastructurally verified transplant glomerulopathy: thickening of the capillary wall in at least three loops in consequence of the widening of the subendothelial space by abnormal basement membrane material, and the formation of a new layer(s) of basal lamina; and chronic rejection: the presence of transplant capillaropathy and/or transplant glomerulopathy and/or transplant arteriopathy. Histologically, chronic transplant nephropathy, chronic rejection, chronic cyclosporine nephrotoxicity, glomerulonephritis, acute rejection, "suspicious" for acute rejection, and "others" were diagnosed in 37%, 34%, 21%, 19%, 57%, 30%, and 5% of the specimens, respectively. The results of EM increased the diagnosis of chronic rejection to 69% of the cases, and decreased chronic transplant nephropathy to 15%. The individual incidence of transplant capillaropathy and transplant glomerulopathy was 79% and 57%, respectively, and their cumulative incidence was 92%. Five biopsies exhibited merely transplant arteriopathy. A late dysfunction typically had more than one cause; the most frequent combination was chronic rejection and acute rejection. In conclusion, the EM search for transplant capillaropathy and transplant glomerulopathy doubled the frequency of the diagnosis of chronic rejection. Currently, the evaluation of renal allograft biopsies from recipients with a late dysfunction relies on standard light microscopy. Because light microscopy per se proved to be insensitive in the diagnosis of chronic rejection, incorporation of EM into the evaluation of late dysfunction biopsies is strongly recommended.

Adolescent↗
PubMed2000

Peritubular capillaries in chronic renal allograft rejection: a quantitative ultrastructural study.

Peritubular capillaries (PCs) with a circumferentially multilayered basement membrane have been suggested as an ultrastructural indicator of chronic renal allograft rejection (CR). The authors validated this lesion as a marker for CR, by analyzing its quantitative features, specificity, and sensitivity in 169 renal biopsy specimens. The mean number of circumferential layers (PCcirc) and the incidences of the grades (mild: 2 to 4, moderate: 5 to 6, severe: 7 or more layers) were investigated in biopsy specimens involving CR (CR(Bx), n = 46), acute rejection (n = 11), normal kidneys (n = 20), psoriatics treated with cyclosporine (n = 13), renal transplants with chronic cyclosporine toxicity (n = 12), native kidney diseases (NKD, n = 56), and transplant nephrectomies attributable to CR (Cr(nephr), n = 11). CR was diagnosed with regard to the clinical features and the presence of intimal fibrosis in 41 biopsy specimens or transplant glomerulopathy in 35 biopsy specimens (cg; identified only by electron microscopy in 10 cases). NKD included chronic glomerulonephritis, chronic tubulointerstitial nephritis, benign nephrosclerosis, thrombotic microangiopathy, diabetic nephropathy, and renal disease in elderly patients (median age, 72 years). All PCs around glomeruli were sampled (median, 14 profiles per case). PCs with a moderate/ severe lesion appeared as serrated profiles with a thick, ribbon-like basement membrane layer in semithin plastic sections. The numbers of circumferentially multilayered PCs were significantly characteristic of CR (PCcirc in CR(Bx): 2.87+/-1.83 SD; range, 0 to 7.36; P < .001 v other groups). A severe lesion occurred exclusively in CR (in 12% of the PCs in CR(Bx), and in 38% in CRnephr). A moderate lesion was observed in 0.6% of the PCs in NKD, 16% in CR(Bx), and 21% in CRnephr. Three or more PCs with a moderate lesion were encountered only in CR. A mild lesion was not suggestive of CR at all. In CR(Bx), 27 cases showed a severe lesion or 3 or more PCs with a moderate lesion (cpc; sensitivity: 59%). Four of the 27 cases lacked cg. The cumulative incidence of cpc and cg was 85%. In transplants with cyclosporine toxicity, the presence of cpc verified the coexistence of CR in 7 specimens. In conclusion, cpc is a specific marker of CR. The incidence of cpc increases as CR progresses. The lesion may be caused by a low-grade rejection injury to the PCs. Careful analysis of semithin sections promotes the better sampling of cpc. An ultrastructural demonstration of cpc and cg defines CR more precisely than does light microscopic evaluation per se.

Adolescent↗
PubMed1999

Ureter diverticulum of transplanted kidney. Case report.

OBJECTIVES: Authors present a case of successful surgical treatment of a ureter diverticulum observed 3 months after kidney transplantation. METHODS: The fluid collection was detected by ultrasound. Percutaneous drainage was performed, after that the excretion of 4 litres of fluid was observed during 12 hours. This finding clearly indicated the connection with the urinary system. This fact was proved and precisely localised by contrast filling of the lesion under fluoroscopic control. RESULTS: Resection of the ureter diverticulum was performed, and the patient recovered fully, there was no change observed in the graft function during the whole procedure. CONCLUSION: The ureter diverticulum is a rare complication after kidney transplantation: the present case is the only one observed among more then 600 kidney transplantations performed during 20 years in our centre.

Adult↗
PubMed1998

[The role of ultrasonography and biopsy following kidney transplantation].

Several complications can occur during both the early and late postoperative periods after kidney transplantation. The methods used to follow up 575 kidney transplanted patients, (transplantations performed between October 1979 and November 1997) in the early (within 6 weeks) and late postoperative periods have been assessed. The diagnostic value of core biopsies and ultrasound examinations, the prevalence of complications, and the applicability of the diagnostic tools in the evaluation of the graft status and viability were analyzed. In the early postoperative period, graft rupture occurred more frequently after biopsy than in the late period (7.4% vs 0.82%), this leading graft loss in 18 of 20 cases. The sonographically diagnosed morphologic and functional changes were also analyzed. Sonography proved a very accurate method for the detection of perirenal fluid collections and masses and severe vascular complications. The data demonstrated that biopsy is indicated in the early postoperative period when the result of sonography is doubtful. In the late postoperative period, biopsy should be performed in every case.

Biopsy↗
PubMed1998

Childhood membranous nephropathy, circulating antibodies to the 58-kD TIN antigen, and anti-tubular basement membrane nephritis: an 11-year follow-up.

Childhood membranous nephropathy (MNP) with anti-tubular basement membrane (anti-TBM) nephritis is a rare disorder that may have extrarenal manifestations. This article describes a new case to be added to the 10 previously reported. A renal biopsy specimen from a 1-year-old white boy with nephrotic syndrome, microhematuria, and hypertension showed MNP (granular global IgG, IgA and C3, and segmental IgM and C1q) associated with hypercellularity and granular deposits of IgM and C1q in the mesangium, arteriolar IgA, and linear TBM IgG, IgA, and C3. A biopsy at age 4 years showed MNP (IgG and C3) and linear IgG and C3 along the TBM. Six months later, temporary glucosuria suggested a mild tubular dysfunction. Biopsy at age 8 years showed sclerosing MNP (IgG and C3), linear TBM IgG and C3, and chronic active tubulointerstitial nephritis (TIN). Indirect immunofluorescence showed circulating anti-TBM antibodies, and the enzyme-linked immunosorbent assay (ELISA) approach verified strong reactivity with the 58-kd TIN antigen. Despite trials with steroids, chlorambucil, azathioprine, and cyclosporine, end-stage renal disease developed by the age of 9 years. At age 10 years, the patient received a cadaveric kidney transplant. With the patient now aged 12 years, the graft is still functioning well, without any clinical evidence of disease recurrence. Neurological, ocular, and abdominal symptoms, including nonbacterial diarrhea, were observed during the follow-up period. The pathophysiology of these extrarenal symptoms remains unclear. Serotyping and genotyping of HLA antigens (A2, A10, B12, B41, DR5 [1101, 1103-4, 1106 or 1108-1113], DR6 [1303, 1312, or 1413], DRB3 [*0101 and 0201-2 or 0301], DQA1 [*0501 homozygous], and DQB1 [*0301 homozygous]) did not indicate any HLA association similar to those described previously in childhood MNP with anti-TBM nephritis (HLA-B7 in four patients, HLA-DR8 in two patients). The presented case is the fifth in the literature that displays reactivity with the 58-kd TIN antigen, and for which data on HLA antigens are reported.

Antibodies↗
PubMed1994

[Comparative analysis of ultrasonic studies, histopathological data and clinical parameters in dysfunctioning renal transplantation].

The correlation of B mode and Doppler sonographic parameters and diagnoses established by histological examination of graft biopsies, nephrectomies and clinical data are discussed. 48 histological samples from 36 patients were reevaluated. The maximum interval between sonography and histology was 36 hours. The Banff classification criteria were used during histological examinations. Doppler examination evaluation was based on the resistance index (RI). Reproducibility was controlled by means of intra- and interobserver variability in 10 patients. RI values higher than 75% were regarded as abnormal. On the basis of these observations and the literature data specific sonographic features can be detected in renal artery occlusion and renal vein thrombosis. In pyelonephritis, dilatation of the collecting system was frequent. No morphological changes were detected in cyclosporin-A nephrotoxicity and the Doppler signs were not characteristic for this disease. No differentiation was found between acute rejection and acute tubular necrosis. The noninvasive duplex sonographic examinations can provide very important information regarding the flow situation of a transplanted kidney. In some cases a definitive diagnosis can be achieved, but in other cases biopsy is the method of choice.

Biopsy, Needle↗
PubMed1991

Comparative distribution of laminin and collagen types I, III and IV in transplant vasculopathy.

Composition of the extracellular matrix (ECM) was studied in transplant vasculopathy occurring in rejected renal allografts using the immunoperoxidase technique with antisera against laminin, and collagen types I, III and IV. In acute transplant vasculopathy the loose ECM network of the intima showed intense immunostaining for laminin and type IV collagen. Type III collagen was detected in the advanced acute cellular intimal proliferations, while early acute lesions did not show immunreactions. Type I collagen was not seen in significant amount. In contrast to these findings in chronic transplant vasculopathy associated with intimal fibrosis the ECM was largely composed of interstitial collagen types III and I, while staining for the basement membrane type ECM components were markedly reduced. Degradation of the matrix components with variable composition was noted in foci of mononuclear infiltrates occurring inside the fibrotic intima. These results indicate that the ECM shows a compositional change in transplant vasculopathy which is associated with the age of the lesion.

Collagen↗
PubMed1991

Pathogenesis of transplantation arteriopathy. Myointimal cells express HLA-DR antigens during rejection.

Arteries were investigated ultrastructurally in material from 40 needle and wedge biopsies of renal allografts, and immunohistochemically in another 10 cases with signs of chronic obliterative transplantation arteriopathy. In the early biopsies, but even in the control kidneys, thin extensions of the smooth muscle cells of the media were observed, which were in direct contact with the endothelial cells through the lamina elastica interna. These extensions may contain receptors mediating endothelial noxae to the smooth muscle cells thus initiating their proliferation, migration to the intima presumably begins in the early post-transplant period and continues until the lumen is occluded. Concomitantly, inflammatory cells (mainly macrophages, with a smaller number of CD4 and CD8-positive T lymphocytes) invade the intima. The proliferating myointimal cells, possibly having become HLA-DR-positive, may behave as antigen-presenting cells, enhancing the anti-graft immune response further, and aggravating the arterial injury.

Cell Movement↗
PubMed1990

[Pathomechanism of the development of chronic obliterative transplantation arteriopathy in human kidney allografts].

Authors examined cells participating in intimaproliferation in transplantation arteriopathy ultrastructurally in needle and wedge biopsy material from 40 transplanted kidneys, and immunohistochemically in 10 cases. In early biopsies--even in two control kidneys--it could be observed that the smooth muscle cells of media are in direct contact with endothel cells by their small processes. Processes can fulfil a receptor function and can transmit endothel noxa to smooth muscle cells. Smooth muscle cells of media react to endothel damage caused by rejection with migration to intima and during this period they are transformed to myofibroblasts (myointimal cells). In the mean time inflammatory cells (mainly macrophages, helper and cytotoxic cells in lower number) from the lumen infiltrate the intima, and mediators, enzymes released from them can inspire smooth muscle cells to further proliferation, migration to intima and transformation to myofibroblast. To effect of mediators (gamma interferon) released from inflammatory cells, the myointimal cells during rejection will press out 2nd class transplantation antigens (HLA-DR), and as vicious circle it further aggravates immune reply to graft, causing vascular damage, intimaproliferation.

Chronic Disease↗