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Biomedical subjects

I Ríha

Publications and source records attributed to I Ríha.

At least 19 recordsLinked to original sources
PubMed2006

[Meningiomas with skull bone involvement].

One of factors responsible for meningioma recurrencies is tumorous involvement of calvarial and basal bone structures. Primary intraosseous meningiomas should be distinguished from secondary involvement in prevailing intracranial tumor and hyperostotic reactive changes. The paper is based on prospective study of 167 patient operated on for intracranial meningioma. Based on clinical investigation, radiological and intraoperative data bone invasion was suspected in 20 patients and histologically confirmed in 17. In 14 patients bone involvement was secondary, meningothelial hamartoma was described in one patient and in 2 patient primary intraosseous meningioma was found. Prevalence of tumors to periorbital area and bone sutures is confirmed. Neuronavigation is used to optimise tumor resection and limit the risk for neurovascular structures. Results were good in 87.5% of patients and poor in 12.5% of patients (extent of tumor and general condition). Discussion provides analysis of intraosseous meningiomas formation, pathological classification (Lang), causes of bone invasion and surgical possibilities. It is necessary to undeline the problems of intraosseous meningiomas both from the aspects of diagnosis and subsequent treatment.

Adult↗
PubMed1997

The in vivo antibody response against exogenous antigens is not influenced by the mouse Bcg (Nramp1) gene.

The mouse Nramp1 (Bcg) gene on chromosome 1 exerts pleiotropic effects on macrophage function. The gene is known to affect presentation of mycobacteria, and other antigens in vitro, so that macrophages carrying the resistant Bcg allele better support the proliferation of antigen-specific T cells compared with macrophages of the sensitive phenotype. To determine whether the Bcg allele could affect in vivo the antibody response to antigens not related to mycobacterial infections, we tested the primary and secondary responses to sheep red blood cells (SRBC) and glycosylated bovine insulin (G-insulin) in two pairs of Bcg congenic strains: BALB/c (Bcgs) versus BALB/c.CD2 (Bcgr), and B10.A (Bcgs) versus B10Ar (Bcgr), and in C57BL/10ScSn (B10; Bcgs) and A/J (Bcgr) mice. Furthermore, the antigen-specific proliferative responses of T cells primed in vivo by protein antigens were also tested in Bcg congenic mice. We found no significant difference in in vivo antibody response either to SRBC or G-insulin between the Bcgr and Bcgs strains. The magnitude of in vitro antigen-specific proliferation of lymph node cells sensitized in vivo by hen egg lysozyme (HEL) or chicken ovalbumin (OVA) was also similar in Bcgs and Bcgr congenic mice. However, we have documented a higher antigen-presenting capacity of Bcgr macrophages in in vitro antigen-specific proliferation to OVA. Since the macrophages are the only cells in which the Nramp1 gene is expressed, we suggest that the activity of other types of antigen-presenting cells masks the effect of the Bcgr allele on antigen-presentation in vivo.

Animals↗
PubMed1997

[Charge interactions of immune deposits in glomeruli (experimental study)].

An i.v. injection of 8-40 mg (kg cationized and heat-aggregated rabbit or human Ig (cat-aggr RIg,-HuIg; pI 9.5) elicited a strong diffuse linear fixation in rat glomerular capillaries revealed by one-step immunofluorescence or immunoenzyme histochemistry 1 and 2 h post-injection. Preferential binding to the lamina rara externa (LRE) was documented in ultrastructure by preembedding and postembedding assays (HRP-coupled antibody and protein A-colloidal gold, respectively). After 24 and 48 h the glomeruli were negative. Polyethylenimine (PEI)-reactive polyanion of LRE was significantly reduced 1 h after cat-aggr-Ig; depletion persisted even after 48 h. Non-cationized Ig aggregates did not bind to the glomerular capillaries. A subsequent i.p. injection of swine anti-rabbit-Ig antibody (SwAR, 15 mg i.p. after 4 h) produced the same linear binding of both two antigens which, however, persisted after 10 days and assumed a granular pattern. After presensitization with RIg (1-2 mg i.p. or s.c.; 4 days before cat-aggr RIg) the early linear fixation underwent a gradual transformation into the granular pattern and deposits of mesangial, rarely of epimembranous type were found 1 week after cat-aggr RIg and later. RIg and SwIg were proved in both types of deposits. After 2 weeks both rat Ig and C 3 were present, too. Rarefaction of deposits and their concentration in the vascular poles took place during 3 months, and deposits also appeared in the media of vas afferens. The antigen load did not produce an acute glomerulonephritis or significant proteinuria; slight focal mesangial sclerosis and a discrete increase in serum creatinine were noted after 2-3 months. To sum up: The one-shot charge interaction is prompt but short-lived whereas the local binding of additional proteins, especially after a specific preimmunization, significantly prolongs the contamination of glomeruli and promotes the build-up of immune complex-type deposits which gradually retreat to the mesangial stalk and vascular pole.

Animals↗
PubMed1996

Limited T helper cell activity in C57BL/10 (B10) mice with inherited low IgG responsiveness.

Due to limitations in antigen processing, mice of the C57BL/10ScSn (B10) strain exhibit a low IgG production against a variety of T-dependent antigens. To characterize the T-cell functions, the authors studied antigen-specific T-cell proliferation and cytokine production in vitro. The response of B10 mice was compared with that of the high IgG producing strain A/J. A highly restricted proliferative response and almost no interleukin-2 (IL-2) and interleukin-3 (IL-3) production was detected in lymph node (LN) cells of B10 mice primed in vivo by protein antigens and subjected to a specific restimulation in vitro, whilst A/J cells responded by significant proliferation and cytokine production. The antigen-specific T-cell response of B10 mice could not be increased by lipopolysaccharide treatment in vivo or by in vitro cultivation with IL-2. However, the T cells of B10 mice produced high levels of IL-2 and IL-4 when stimulated by phorbol myristate acetate (PMA) and Ca2+ ionophore, proving the existence of a functionally intact signal transduction pathway downstream of protein kinase C (PKC). The results suggest that the in vivo antigen priming does not effectively activate the T cells in B10 mice. The limited activation consequently leads to the low IgG response described in B10 mice.

Animals↗
PubMed1993

IL-2 and IL-3 production in high and low IgG-responding strains of mice.

The antibody response of mouse strain C57Bl/10ScSn (B10) is characterized by a low IgG responsiveness to a number of different antigens. Aberrant function of antigen-presenting cells and/or low activity of the Th cell population have been suggested as the cause of the defect. We studied the production of IL-2 and IL-3 in vitro by unstimulated and ConA-stimulated spleen cells. Unstimulated spleen cells of low-responding B10 mice produce significantly less IL-2 compared with the high-responding A/J mice in both intervals tested, i.e. after 24 and 48 h of in vitro incubation. IL-3 production is low but almost comparable in unstimulated cells of both strains. Stimulation of spleen cells by 5 micrograms/ml of ConA leads to considerably higher production of IL-2 in A/J spleen cells. IL-3 production by ConA-stimulated spleen cells showed the same pattern of activity. This low IL-3 production by B10 cells is most likely due to the low production of IL-2 during Th cell activation and to the limited proliferation of these cells. The low IgG production of B10 spleen cells during the secondary response to SRBC in vitro could be restored by IL-2 added to the medium. 50 U/ml of IL-2 increased the number of anti-SRBC IgG-producing cells 40 times in B10 cells, but only 4 times in A/J cells, so that the IgG production in B10 cells reached the same level as that in the A/J cells without exogenous IL-2. We suppose that the limited IL-2 production in the low-responding strain B10 is the cause of the low IgG responsiveness of these mice.

Animals↗
PubMed1991

Thy 1 expression in the brain of nude mice.

The expression and cell distribution of Thy 1 antigen was studied in the brain of both normal and athymic (nude) young adult mice of the BALB/c strain by immunochemistry. In nude animals Thy 1 fluorescence was less intense and less regularly distributed in the molecular layer of the cerebellum and hippocampus. Thy 1 content determined by ELISA was lower by 10-16% in the cerebellum and 20-25% in the olfactory bulbs of nude mice. The total wet weight of the brain was lower by 16% than in control animals; the deficit in body weight ranged from 34-45%. It is supposed that the changes in Thy 1 expression in nude animals are caused mainly by the underdevelopment of late developing brain regions due to thermoregulatory problems and other postnatal strains occurring in the mutants.

Animals↗
PubMed1990

Experimental ablation nephropathy. Fine structure, morphometry, cell membrane epitopes, glomerular polyanion and effect of subsequent transplantation.

The subtotal (5/6) nephrectomy performed in 23 adult female rats induced severe hypertrophy of residual parenchyma with interstitial fibrosis, tubular dilatation, and focal and segmental glomerulosclerosis (FSG). This ablation nephropathy (AbN) caused proteinuria, progressive renal failure, and hypertension. The extent of FSG was assessed by semiquantitative scoring. The ultrastructure revealed widespread foot process fusion, many dense cytoplasmic inclusions in podocytes, and degenerative changes or disruption of mesangium with glomerular "microcysts". Numerous granular deposits of rat Ig were seen in the glomeruli but a short praeterminal i.v. load by heat-aggregated human Ig did not alter the morphology of AbN and produced discrete and inconstant glomerular deposits. Similarly an i.v. injection of protamine and heparin generated protamine-heparin complexes seen in various layers of glomerular capillary wall, similar to those found previously in normal rats. AbN displayed a partial irregular depletion of polyanion sites reactive with polyethylenimine in lamina rara externa. A significant increase in both glomerular and interstitial Ia+ cells and a marked predominance of W3/25+ cells in the interstitial infiltrates were documented by immunohistochemistry in the remnant kidneys. Both AbN and FSG could be largely corrected (or prevented?) by subsequent syngeneic renal transplantation (TPL; 6 animals). On the other hand a severe AbN was found in two post-ablation residues after unsuccessful TPL with graft necrosis or sclerosis.--AbN has some analogies to various chronic human nephropathies (e.g. FSG) and may explain their progression to the terminal failure. Degenerative and finally destructive mesangial lesion seems to be of prime importance in AbN.

Animals↗
PubMed1990

Omental dendritic cells: Ia expression and relation to macrophages.

Rat omental dendritic cells (ODC) occur in two forms, mainly spindle-shaped, Ia-, on the surface, and stellar, Ia+ within the omentum. Like macrophages, most ODC label with W3/25 mAb and have a demonstrable activity of non-specific esterase, acid phosphatase and ATPase. Up to 30% of ODC are actively phagocytic. The proportion of Ia+ ODC rises 7 days after ip antigenic stimulation and there seems to be a reciprocal development of Ia positivity and phagocytic capacity between ODC and macrophages 3 and 5 days after ip immunization. ODC contribute to the overall fluctuation of Ia expression in the entire omentum after immunization. Ia+ ODC display a linear arrangement along preilymphatic spaces and may be related to the formation of new lymph vessels. They also constitute the stroma of pseudofollicles containing clusters of what are presumably T-helper lymphocytes closely attached to ODC, scattered suppressor T lymphocytes and B cells accumulating in later stages at the immune response.

Acid Phosphatase↗
PubMed1989

Detection of cationic and non-cationic markers in the rat glomerulus by electron probe analysis.

Acidic glycans (glomerular polyanion substances) in the rat kidney were visualized ultrastructurally by three cationic markers: colloidal iron, ruthenium red, and polyethylenimine-phosphotungstic acid (PEI-PTA). Heavy metal atoms (Fe, Ru and W) were detected in ultrathin sections by energy-dispersive electron probe microanalysis (EPMA). Characteristic peaks of the locally bound elements were obtained in spectra derived from the dense structures seen by transmission electron microscopy (TEM)--i.e. the glycocalyx of podocytes and/or the polyanion sites in the lamina rara externa of the glomerular basement membrane. Weaker signals were emitted by some extraglomerular structures. This finding may reflect a low concentration of glycans in structures lacking apparent density by TEM, and/or incomplete specificity of the markers, partial dislocation of reactive substances or the presence of an endogenous element (Fe). Experimental argyrosis was elicited by the peroral administration of silver nitrate. Dense Ag precipitates were seen chiefly in the lamina densa and characteristic peaks of silver were displayed in this site by EPMA, and was best demonstrated in non-contrasted sections. A single i.v. injection of Ag proteinate failed to produce glomerular pigmentation. The only dense granular product in tubular cells yielded characteristic peaks of Fe (endogenous siderosomes) but EPMA excluded detectable amounts of silver.

Animals↗
PubMed1987

Protein aggregates in extracorporally perfused rabbit kidneys.

Eighteen rabbit kidneys were perfused ex vivo for 1 h with allogeneic blood, and in 16 a solution of xenogeneic aggregate-free, aggregated or antibody-complexed protein was added to the perfusate 5 min after the start (human immunoglobulins or serum albumin, partly cationized, were used). The kidneys were examined by light and electron microscopy and the human and rabbit immunoglobulin (or albumin) precipitates were detected by direct immunofluorescence and ultrastructural immunohistochemistry. In 13 kidneys the perfusion produced small segmental glomerular endocapillary aggregates of platelets, leukocytes, and granular precipitates reactive with both anti-rabbit and anti-human antibodies. No typical deposits were seen in mesangium or in periphery of glomerular capillaries but rabbit Ig penetrated to the inter- and subepithelial spaces of proximal convoluted tubules. Three kidneys perfused by cationized aggregated human Ig (or by cationized albumin-antialbumin complexes) exhibited a destructive lesion with rapid breakdown of blood flow and massive global endocapillary plugs of similar ultrastructure but with focal endothelial sloughing. Pericapillary granular precipitates of human and rabbit Ig were seen in these kidneys. When the blood with cationized Ig aggregates was used for perfusion of two further kidneys extensive endocapillary aggregates with endothelial damage reappeared but the extracapillary penetration and precipitation were lacking and the blood flow largely improved. Membrane polyanion of podocytes stained by colloidal iron was preserved even in close proximity of cationized complex precipitates. Thus, in the ex-vivo perfusion model the preformed neutral aggregates did not penetrate through the glomerular capillary wall and were not phagocytized by mesangial cells. The cationized aggregates induced rapid circulatory failure with massive platelet clumping and granular pericapillary "humps" ultrastructurally different from the deposits of human and experimental immune complex glomerulonephritis.

Animals↗
PubMed1986

Different handling of antigen by macrophages of low responder C57BL/10ScSn strain and high responder A/J strain of mice. I. Presentation of antigen and induction of helper and suppressor cells.

The SRBC-pulsed peritoneal macrophages from low IgG producing B10 mice were defective in induction of primary as well as secondary antibody responses in (A/J X B10)F1 recipients. This is most probably due to a low number of Ia+ macrophages in the defective B10 mice. Immunization caused a significant increase in numbers of Lyt 2+ cells in spleens of the B10 strain, whereas the percentage of L3T4+ cells remained unchanged. The opposite situation was found in mice of the high responding A/J strain. Simultaneous application of LPS and SRBC prevented the elevated appearance of Lyt 2+ cells in spleens of low responding B10 mice.

Animals↗
PubMed1985

Low IgG response of the mouse strain C57BL/10ScSn after immunization with protein antigens.

The low IgG response of the strain C57BL/10ScSn is not restricted to the reaction to sheep red blood cells; but it can be demonstrated even after immunization with ARS, DNP or FITC haptens, coupled to various heterologous (BGG, RSA) or autologous (MGG) protein carriers. The level of the IgG response is - using the same immunization schedule - influenced both by the bound hapten and the carrier. In both strains tested (i.e. in the high-responding A/J and the low-responding C57BL/10ScSn), the highest IgG response is elicited by FITC-BGG. The response of the C57BL/10ScSn strain is, similarly as after immunization with SRBC, approximately ten times lower. The IgG response to other antigens tested was lower in both strains and therefore the quantitative differences were less pronounced. The affinity of antibodies against the ARS and TNP determinant, detected by inhibition of plaque-forming cells, is similar in the two strains. Thus the low reactivity of the strain C57BL/10ScSn is not caused by the absence of suitable VH and VL genes, but it rather indicates a defect of some general regulatory mechanism, involved in the synthesis of IgG antibodies. After repeated administration of ARS-BGG, the antigen and the antigen - antibody complexes accumulate in high concentrations primarily in the liver of mouse strain A/J. The amount of antigen accumulated in the liver of strain C57BL/10ScSn is significantly lower.

Animals↗
PubMed1984

Immunostimulatory effect of cis-diamine dichloroplatinum (II).

Cis-diamine dichloroplatinum (II) (DDP) injected i.p. or i.v. at the dosage of 0.83 mg/kg to BALB/c mice on days 0, 7 and 14 elicited antibodies against proteins (RSA, BGG) and haptens (TNP, FITC) detectable by ELISA or by passive haemagglutination. Significant increase in antibody production was observed with either route of DDP application. A similar set of antibodies against antigens which do not cross-react with the immunizing proteins was observed when mice were immunized with complexes formed by an in vitro incubation of RSA and BGG with DDP. Thus, proteins modified in vivo or in vitro by DDP may stimulate the production of antibodies of unexpected specificities.

Adjuvants, Immunologic↗
PubMed1984

Interaction of xenogeneic antiglomerular antibodies with foetal pig tissues.

Rabbit anti-swine-glomerular-immunoglobulin (AG Ig) was administered in utero to 14 pig foetuses 40-103 d post-conception. In nine foetuses AG Ig was injected into the umbilical vein and 60 min later kidneys and other organs were collected. In five others, AG Ig was injected via the intact uterine wall, and the tissues were examined after further 11 or 35 d of uninterrupted pregnancy. No signs of glomerular inflammation were found by light microscopy. In electron microscopy, especially in younger foetuses, focal endothelial defects and subendothelial granular "deposits" were seen in deep glomeruli, but they appeared also in control foetuses of corresponding age. Immunofluorescence microscopy showed a strong diffuse linear positivity of the swine-anti-rabbit-Ig conjugate in the capillary loops of deep juxtamedullary glomeruli irrespective of foetal age and dose of antigen injected. Immature glomeruli and S-bodies yielded a poor to negative staining. Proof of swine Ig was negative in all kidneys as well as the test for rabbit and swine Ig in various other organs. Traces of rabbit Ig were only detected in disseminated platelet aggregates of myocardium in the early post-injection period. Ultrastructural enzyme-antibody assay visualized AG Ig throughout all three layers of glomerular capillary basement membrane, and in the early period signs of transendothelial passage and escape of unbound rabbit Ig molecules were evident. The mesangial matrix, cell membranes, and extraglomerular basement membranes remained all negative. As follows, xenogeneic antiglomerular antibodies specifically react with target structures even at the end of the first third of intrauterine life, afflicted being only the deep mature polyanion-coated glomeruli. The foetal immune system is incapable of an adequate autologous antibody response, and we have failed to find even an early glomerular lesion comparable with the postnatal anti-basement-membrane glomerulonephritis.

Animals↗
PubMed1981

Genetic regulation of antibody response to sheep red blood cells: isoelectric focusing analysis of sera of well responding strain A/J and poorly responding strain B10 mice.

Isoelectric focusing (IEF) on a thin layer of polyacrylamide gel revealed that strain A/J produces antibodies with pI values distributed over the whole assayed pH range (pH 5.05-7.75), while strain B10 produces antibodies of a limited heterogeneity with pI values distributed between pH 6.3 and 7.5. The analysis of sera of congenic resistant (CR) and recombinant strains showed that haplotype H-2a is associated with wide-heterogeneity antibodies, while the presence of haplotype H-2b is associated with the occurrence of limited-heterogeneity antibodies. Thus a gene located within the I region of the major histocompatibility complex (MHC) may affect the degree of heterogeneity of the anti-sheep red blood cell (SRBC) response. The gene is transmitted to the F1 generation as a dominant trait. After administration of endotoxin (LPS LT2, 10 microgram/mouse) to the B10 mice, antibodies with pI values below pH 6.3 and above 7.5 appear in the serum; the heterogeneity of these antibodies resembles that of the A/J strain spectrotype.

Animals↗
PubMed1981

Genetic regulation of antibody response to sheep red blood cells: linkage to H-2 complex.

The analysis of anti-sheep red blood cell (SRBC) antibody production in the congenic resistant (CR) mouse strains A/J and A.BY, B10 and B10.A showed that the level of IgG antibodies after immunization with SRBC is controlled by a gene(s) localized in the H-2 complex. The use of h2,h4, and i5H-2 recombinant haplotypes allowed us to map this gene into a region proximally defined by subregion I-J and distally by region H-2G. The IgG antibody level is simultaneously under the influence of non-H-2 genes, of which those of the A/J strain origin determine the high IgG level and those of the B10 strain origin determine the low IgG level. Weights of spleens of the A/J and B10 mice before and after primary and secondary immunization with SRBC were compared. Before immunization, spleens of the A/J mice were approximately 10% lighter than those of the B10 mice (0.08 g vs 0.09 g). After the first immunization the spleen weights equalized (0=0.12 g). Four days after the second immunization the weight of the spleens of A/J mice increased by 312% (relative to the nonimmune state) while that of the B10 mice increased by only 74%. These findings indicate that the cell antigen-specific proliferation in spleens of A/J mice was considerably higher than that in spleens of B10 mice.

Animals↗