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I Blasko

Publications and source records attributed to I Blasko.

15 recordsLinked to original sources
PubMed2000

The amyloid beta peptide abeta (25-35) induces apoptosis independent of p53.

Apoptosis of neuronal cells apparently plays a role in Alzheimer's disease (AD). The amyloid beta (Abeta) peptide derived from beta-amyloid precursor protein is found in AD brain in vivo and can induce apoptosis in vitro. While p53 accumulates in cells of AD brain, it is not known if p53 plays an active role in Abeta-induced apoptosis. We show here that inactivation of p53 in two experimental cell lines, either by expression of the papillomavirus E6 protein or by a shift to restrictive temperature, does not affect apoptosis induction by Abeta (25-35), indicating that Abeta induces apoptosis in a p53-independent manner.

Amyloid beta-Peptides↗
PubMed2000

Diseases of aging.

By definition, diseases of aging become clinically manifested in elderly patients. However, their pathogenetic basis has to be sought earlier in life. The general thread of this presentation relies on the concept of an evolutionary-Darwinian view of the development of age-related diseases. In essence, this concept states that we may have to "pay" for genetic traits that play a beneficial role earlier in life by the later development of diseases since there is no post-reproductive selective pressure that may have eliminated the potential late onset detrimental effects of such genes. Examples for this kind of trade-off are taken from diseases involving the immune system (infections), the endocrine system (andropause), the nervous system (Alzheimer's disease), the locomoter system (osteoporosis), the cardio-vascular system (atherosclerosis) and cancer.

Adult↗
PubMed1999

Transfected human B cells: a new model to study the functional and immunostimulatory consequences of APP production.

The ubiquitously expressed Alzheimer amyloid precursor protein (APP) has raised wide interest in view of its connection with Alzheimer's disease. We now provide a novel extraneuronal cell model in which human Epstein-Barr virus transformed B cells that constitutively hardly produce APP are transfected with wild-type or mutated APP695, harboring the Swedish mutation APPsw, or a dilysine endoplasmic reticulum retrieval motif--APP(ER). This leads to the generation of three types of cells, one with a high secretion of soluble APPs but low levels of intracellular APP, another with a high intracellular APP retention but a low APP secretion, and a third in which APP maturation and secretion are strongly impaired. The suitability of our cell model for various purposes is proven by its usage in different systems. We demonstrate that it is a useful tool for studies on the physiology of APPs and represents a good model system to analyze the cellular mechanisms of Abeta-directed autoimmune reactivity.

Amyloid beta-Protein Precursor↗
PubMed1999

TNFalpha plus IFNgamma induce the production of Alzheimer beta-amyloid peptides and decrease the secretion of APPs.

The appearance of inflammatory markers associated with amyloid plaques indicates a state of chronic inflammation in Alzheimer's disease (AD). Multiple epidemiological studies also suggest that patients taking anti-inflammatory drugs have a decreased risk of developing AD. Here we present evidence that inflammatory cytokines can alter the metabolism of the beta-amyloid precursor protein (betaAPP). We show that the combination of tumor necrosis factor alpha and interferon gamma triggers the production of beta-amyloid peptides and inhibits the secretion of soluble APPs by human neuronal and extraneuronal cells. The results demonstrate a new mechanism by which inflammatory components can exacerbate the fundamental pathology in AD.

Alzheimer Disease↗
PubMed1999

Mechanisms of immune regulation in Alzheimer's disease: a viewpoint.

The immune system may play an important role in the neurodegenerative process in Alzheimer's disease (AD). Complement components, eicosanoids and cytokines are found in cerebral amyloid plaques. These inflammatory proteins may stimulate the amyloid beta (Abeta) production, support its aggregation and increase its cytotoxicity, thus aggrevating the pathology of AD. Abeta may trigger their release from activated microglia and astrocytes which are the main sources of these proteins. However, there are also indications for a protective role of the immune system against the development of AD. Microglial cells have been shown to degrade Abeta and recent evidence suggests a role of autoreactive Abeta-specific T cells in the elimination of the peptide. This mechanism seems to be impaired in the majority of patients with AD. An Abeta-specific immune reaction may thus represent a natural defence mechanism directed against the accumulation of dangerous amyloidogenic substances. Impairment of the immune system and the failure to eliminate a toxic metabolite can be the basis for a chronic non-specific inflammatory process in the brain, as described above. AD is a good example how an immune response may lead to tissue destruction and neuronal loss instead of maintaining the integrity of the body.

Alzheimer Disease↗
PubMed1998

Sex steroids do not prevent amylin-induced apoptosis in human cells.

Formation of amylin-containing islet amyloid deposits may contribute to the progressive deterioration of beta cell function in non-insulin-dependent diabetes mellitus. As diabetes mellitus occurs in male, but rarely in female transgenic mice expressing human amylin in their pancreatic beta cells, it is of interest to study the influence of estradiol (E2) and testosterone (T) on amylin-induced cytotoxicity in human cells. The insulinoma cell line CM, thyroid epithelial cells (TEC) in primary culture, and nontransformed fibroblast lines were used. The occurrence of apoptotic cell death was assessed by nuclear labeling with propidium iodide. Amylin was cytotoxic on all cell types tested, but had the most pronounced effect on TEC and the weakest on the CM cell line. Although both E2 and T decreased the proportion of apoptotic cells in cultures kept in the absence of amylin, neither of the two hormones was able to counteract amylin-induced cytotoxicity. beta cell death and hyperglycemia can thus presumably not be prevented by the neutralization of amylin effects by sex steroids.

Amyloid↗
PubMed1998

The production of the Alzheimer amyloid precursor protein (APP) in extraneuronal tissue does not increase in old age.

Alzheimer's disease (AD) is characterized by the cerebral deposition of beta-amyloid (A beta). A beta plaques also occur in the brains of healthy aged individuals, and A beta concentrations are increased in the cerebrospinal fluid (CSF) in old age. Based on results from an in vitro senescence model on human fibroblasts, it was proposed that the production of the beta-amyloid precursor protein (APP) was increased during aging. No information was available as to whether APP production was also augmented in aged humans. It was therefore the aim of the present study to analyze APP in connective tissue, skeletal muscle, peripheral blood mononuclear cells, and serum samples from young and aged healthy individuals. APP production was assessed by Northern and Western blotting. The expression of the different APP isoforms was studied by reverse transcription-polymerase chain reaction (RT-PCR) technique. The results demonstrate that APP messenger ribonucleic acid (mRNA) and protein concentrations were identical in blood and tissue samples from young and aged individuals and that there were no age-dependent changes in the APP isoform production pattern. Thus, our data strongly argue against the possibility of an altered production of APP during healthy aging and underline the point that in vitro aging models may not accurately reflect the in vivo situation.

Adult↗
PubMed1997

Tumor necrosis factor alpha augments amyloid beta protein (25-35) induced apoptosis in human cells.

No information is yet available on the effect of tumor necrosis factor alpha (TNFalpha) on amyloid beta protein (Abeta)-induced cytotoxicity in human cells. For this reason the induction of apoptosis by TNFalpha and Abeta (25-35) was studied in primary cultures of human thyroid and kidney cells as well as in the neuroblastoma line SK-N-SH and in DU-145 cells. Apoptosis occurred in all cell types after Abeta (25-35) treatment, but was markedly enhanced when TNFalpha was additionally present. This effect was less pronounced in transformed cell lines than in primary cultures, in which TNFalpha on its own was not cytotoxic. Apoptosis was still more prevalent under serum free culture conditions. The results demonstrate that TNFalpha may support the occurrence of Abeta-mediated cell death and thus contribute to the development of pathological changes in Alzheimer's disease (AD).

Amyloid beta-Peptides↗
PubMed1991

[Long-term results of the Collona acetabuloplasty].

The authors evaluate in their paper the long-term results of capsular acetabuloplasty by Colonna's method in the material of the First Orthopaedic Clinic, Faculty Hospital Bratislava. The mean time interval after operation was 20 years. The results are compared with previous evaluations made by Cervenanský and Kalman. Very favourable results were recorded in 3% of the patients, good results in 24%, satisfactory results in 39% and poor results in 39% and poor results in 34% of the patients. A marked shift towards unsatisfactory results is due to incorrect indication of acetabuloplasty which in the was a certain compromise, and also due to the surgical technique. The authors assume that correct and early prevention and treatment will eliminate capsular acetabuloplasty from the range of standard surgical therapeutic procedures in L.c.c.

Acetabulum↗
PubMed1989

[Problems in the diagnosis of Ewing's sarcoma].

The aim of the work was to analyze by the method of retrospective study the difficulties in diagnosing the Ewing sarcoma at the Department of Orthopaedic of the Teaching Hospital in Bratislava in the years 1967-1987. The authors found out that there were diagnosticated 28 cases of the Ewing sarcoma, the boy-girl ratio was: 1:1. Most frequently it occurred between 12 and 18 years of age. Apart from clinical examination they use classical sciagraphy, macropictures, tomography, arteriography, gammagraphy of the skeleton, computer tomography, lymphography, histological, and electron microscopic examination. In the conclusion the authors point out that the timely treatment may be ensured by a precise and demanding screening carried out by pediatricians, practitioners in charge of adolescents and orthopaedists and by further reduction of the time interval necessary for performing all above mentioned examinations. The care of the Ewing sarcoma is the responsibility of suitably equipped special centres of bone oncology.

Adolescent↗
PubMed1989

[Mineralization status in bones in patients with femoral neck fractures].

The authors present the results of the evaluation of the state of the art of mineralization of the bone in 56 patients over 45 years of age with the fracture of the femoral neck. The state of the art of mineralization was evaluated by means of bone indices. In each patient there were determined 6 values of bone indices and thus they got a more objective picture of the state of the art of bone tissue. They found out that most cases of fractures occurred on the osteporous skeleton. For pathological values corresponding to osteoporosis they considered such values when the bone index according to Barnet-Nordin was less than 45, Garn index less than 67, Singh index equal to the values I, II, III and Kocian index corresponded to normograms. Lower cortico-diaphyseal index on the side of the fracture in comparison with the contralateral side they explain by timely demineralization after the fracture during immobilization. Proceeding from the results achieved they emphasize the necessity of a timely prevention and treatment of osteoporosis.

Aged↗
PubMedDate not supplied

The possible role of the immune system in Alzheimer's disease.

Currently, there is little doubt that the immune system plays a role in the neurodegenerative process in Alzheimer's disease (AD). Inflammatory proteins such as complement components, enzymes, eicosanoids, and cytokines are found in association with cerebral amyloid plaques and may exacerbate the fundamental pathology of AD, by stimulating Amyloid beta (A beta) production, supporting its aggregation and increasing its cytotoxicity. Activated microglia and astrocytes are the main source of these proteins, and A beta may trigger their release. Interestingly, there are also indications that the immune system may play a protective role against the development of AD. Microglial cells have been shown to degrade A beta, and recent evidence suggests that autoreactive A beta-specific T cells may be relevant to the elimination of the peptide. This mechanism seems, however, impaired in the majority of patients with AD. The immune system seems thus to represent a natural line of defense against the accumulation of dangerous amyloidogenic substances. Impairment of this specific immunological defense mechanism and the failure to eliminate a toxic metabolite can be the basis for a chronic nonspecific inflammatory process in the brain, as described above. AD is a good example how an immune response initially aiming at maintaining the integrity of the body may fail and consequently lead to tissue destruction and neuronal loss.

Alzheimer Disease↗