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Biomedical subjects

I Kiss

Publications and source records attributed to I Kiss.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hydrogen-dependent denitrification in a two-reactor bio-electrochemical system.

An autotrophic biological process was developed for the treatment of nitrate-contaminated drinking water. The system comprised of two steps: the water to be treated was first enriched with hydrogen (energy source) in the cathodic chamber of an electrochemical cell, and then denitrified in the bioreactor. The bioreactor was a packed bed of granulated activated carbon, and the water flow was directed in an upward continuous mode. The system was operated for one year, at various water velocities and current intensities. Denitrification rates up to 0.25 kg N m-3 d-1 were obtained at the hydraulic residence time of 1 h. The system was stable. When detected in the effluent, the concentration of nitrite was low, even under conditions that resulted in the elution of very high concentrations of nitrate.

Bioreactors↗
PubMed2001

Working memory deficits associated with chronic fatigue syndrome.

Cognitive impairments are among the most frequently reported and least investigated components of the chronic fatigue syndrome (CFS). As part of a multifaceted study of the CFS, the present study investigated the cognitive functioning of chronic fatigue patients. The performance of 20 CFS patients was compared to that of controls (N = 20) on 4 tests of working memory (WM). Digit Span Forward was used to assess the storage capacity of WM. Multiple aspects of central executive functioning were assessed using several standard measures: Digit Span Backward, and Trails A and Trails B. More recently developed measures of WM were used to assess control of processing under temporal demands (working memory task) and resistance to interference (a sustained attention task). Deficits were restricted to more demanding tasks, requiring resistance to interference and efficient switching between processing routines. The overall results clearly implicate deficits in the control aspects of central executive function in CFS.

Adolescent↗
PubMed2001

Association between gastric cancer mortality and nitrate content of drinking water: ecological study on small area inequalities.

The carcinogenic feature of N-nitroso compounds has been well established. Similarly, the transformation of ingested nitrate to N-nitroso compounds in the stomach has been thoroughly documented, nevertheless nitrates' carcinogenic effect has not been proved convincingly in human. The present study was aimed to investigate a population of small villages provided by drinking water with high and widely variable nitrate content (72 mg/l median, 290.7 mg/l 95-percentile concentration). Empirical Bayes estimates for settlement-specific age-, sex-, and year-standardised mortality ratios of gastric cancer (GC) were related to the settlement level average nitrate concentrations in drinking water controlling for confounding effects of smoking, ethnicity and education. The log-transformed average nitrate concentration showed significant positive association with stomach cancer mortality in linear regression analysis (p = 0.014). The settlements were aggregated according to the nitrate concentration into 10-percentile groups and the standardised mortality ratios (SMRs) were calculated. Those groups with higher than 88 mg/l average nitrate concentration showed substantial risk elevation and the log-transformed exposure variables proved to be significant predictors of mortality (p = 0.032) at this level of aggregation also. The association seemed to be fairly strong (r2 = 0.46). Although this investigation constituting an ecological study has certain limitations, it supports the hypothesis that the high level of nitrate in drinking water is involved in the development of GC.

Bayes Theorem↗
PubMed2001

Cofilin/ADF is required for cell motility during Drosophila ovary development and oogenesis.

The driving force behind cell motility is the actin cytoskeleton. Filopodia and lamellipodia are formed by the polymerization and extension of actin filaments towards the cell membrane. This polymerization at the barbed end of the filament is balanced by depolymerization at the pointed end, recycling the actin in a 'treadmilling' process. One protein involved in this process is cofilin/actin-depolymerizing factor (ADF), which can depolymerize actin filaments, allowing treadmilling to occur at an accelerated rate. Cofilin/ADF is an actin-binding protein that is required for actin-filament disassembly, cytokinesis and the organization of muscle actin filaments. There is also evidence that cofilin/ADF enhances cell motility, although a direct requirement in vivo has not yet been shown. Here we show that Drosophila cofilin/ADF, which is encoded by the twinstar (tsr) gene, promotes cell movements during ovary development and oogenesis. During larval development, cofilin/ADF is required for the cell rearrangement needed for formation of terminal filaments, stacks of somatic cells that are important for the initiation of ovarioles. It is also required for the migration of border cells during oogenesis. These results show that cofilin/ADF is an important regulator of actin-based cell motility during Drosophila development.

Actin Depolymerizing Factors↗
PubMed2001

Age-related decline in perception of prosodic affect.

Perception of affect in speech is an important aspect of language, often conveying more about the intent of the speaker than semantic content. Impairment of perception of affect is seen in patients with right-hemisphere lesions. Nevertheless, little attention is paid to perception of emotional prosody in clinical neuropsychology. We present data concerning a revised version of the Emotional Perception Test (EPT-R), which indicates that older participants are significantly worse in prosodic perception than IQ-matched younger participants. The apparent age-related differences in perception of prosody are similar in magnitude to those seen on memory tests.

Adult↗
PubMed2001

Bovine abortion associated with Neospora caninum in Hungary.

The authors report the first case of bovine neosporosis in Hungary based on investigations made on an aborted fetus. The diagnostic methods included traditional as well as molecular techniques. This record extends further the geographic range of the disease.

Abortion, Veterinary↗
PubMed2001

Role of environmental factors on the reproducibility of Lemna test.

Lemna minor is a species easy to collect and culture in laboratory, and can give rapid test results. However, in order to standardise toxicity tests using Lemna minor as test organism, it is important to find out what natural variability different populations might have. Five Lemna populations were used for comparison. It contained two standard cultures and three populations collected in natural habitats. Potassium dichromate was applied as test material. Lemna populations cultured under the same conditions showed different T(D) and LC50 values. There is an inverse relation between the sensitivity and T(D) of the strains. It is supposed that growth rate and sensitivity of Lemna populations depend on environmental factors characterising the habitat in which the given popluation originally lives.

Magnoliopsida↗
PubMed2001

[Investigation of oncogene amplification or deletion, and oncoprotein expression in papillary thyroid cancer]

AIM: Assessment of occurrence and possible prognostic significance of c-myc and Ha-ras amplification, p53 deletion and overexpression of cyclin D1, p53 and p21 in papillary thyroid cancer. MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded tumor tissue from 24 patients were investigated. Dot-blot DNA hybridization was used to detect oncogene amplification or deletion. The expression of oncoproteins was determined by immunohistochemical method. RESULTS: In our samples neither Ha-ras amplification nor p53 deletion were found. Low c-myc amplification (mean: 2.55) occured in 4 cases (17%). p53 protein was detected in 16 samples (66.6%), with p21 expression (chi(2)=7.02, p<0.01) in 6 cases (25%). The p53 expression did not influence the tumor fenotype. Cyclin D1 overexpression was found in 12 cases (50%), it was often associated with p21 expression (chi2=10.1, p<0.001) and in inverse relation to the tumor lymphocytic infiltration (chi(2)=5.35, p<0.05). Increased expression of estrogen receptor was shown in 4 cyclin D1 positive samples (17%). CONCLUSIONS: The p53 detected in our study is likely not to be mutant protein in all cases because its presence was associated with p21 expression that the mutant protein cannot induce and also it did not mean more aggressive tumor phenotype. The connection of cyclin D1 overexpression with the lymphocytic infiltration of the tumor suggests that the increased expression of cyclin D1 means poor prognosis. The coexpression of cyclin D1 and p21 raises the modulative character of the p21 protein, thought to be a tumor suppressor originally, but we find a CDK-independent, estrogen receptor mediated effect of cyclin D1 more likely, which has been described in breast cancer and is also proved by the coexpression of cyclin D1 and estrogen receptor detected here.

Journal Article↗
PubMed2001

[In vitro testing for drug resistance and drug sensitivity in clinical oncology].

In vitro methods for testing chemosensitivity and chemoresistance can contribute considerably to more individual chemotherapy of a given patient. Different tests which reflect with a different reliability and specificity the probable ineffectiveness of chemotherapy can be divided into several categories: 1. Indirect tests associated with general biological activity of the tumour. 2. Tests based on the specific relationship to a certain cytostatic. 3. Examination of hormonal receptors. 4. Direct tests based on testing of the sensitivity or resistance of a tumour to different cytostatics in primocultures or stabilized cultures. The submitted review presents information on different methods.

Animals↗
PubMed2001

[Personal experience with intra-arterial locoregional chemotherapy of liver metastases from colorectal carcinoma].

Locoregional chemotherapy is one of the possible ways of treatment of inoperable metastatic affection of the liver by colorectal carcinoma. The advantage of regional administration of the cytostatic is the possibility to achieve a higher local concentration of the cytostatic associated with a higher percentage of therapeutic responses. In our department we preferred combined locoregional intraarterial chemotherapy (5-fluorouracil/Mitmycin C/Doxorubicin) combined with systemic intravenous chemotherapy (5-fluorouracil/leukovirin). Locoregional cghemotherapy was administered in the majority as chemotherapy of series 2 or 3 with a very good tolerance. In 2/19 patients we observed marked diminution of liver metastases and subsequent operability and with a duration of complete response for 13 and 18 months. In 7/19 patients a partial therapeutic response was achieved. The total therapeutic response (complete and partial) was 47%. Locoregional chemotherapy attains a higher therapeutic response as compared with systemic chemotherapy and is associated with an acceptable toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Prod is a novel DNA-binding protein that binds to the 1.686 g/cm(3) 10 bp satellite repeat of Drosophila melanogaster.

The proliferation disrupter (prod) gene of Drosophila melanogaster encodes a novel protein associated with centromeric chromosomal regions that is required for chromatin condensation and cell viability. We have examined the binding of the Prod protein to DNA in vitro. Co-immunoprecipitation experiments demonstrate that Prod is a DNA-binding protein that specifically recognizes the 10 bp AGAATAACAT satellite repeat of D.melanogaster. Footprinting experiments show that the protein interacts with a 5-8 bp target sequence in each 10 bp repeat and suggest that it can mediate condensation of this satellite into a superhelix. Gel retardation experiments indicate that Prod does not have a well defined DNA-binding domain and it binds the satellite in a co-operative manner, probably forming Prod multimers. Since Prod localizes to both heterochromatin and euchromatin in vivo, we discuss the possibility that the ability of pre-existing euchromatic proteins to bind DNA in a co-operative manner, might be a prerequisite of satellite compaction and satellite amplification, thereby providing a basic factor in heterochromatin evolution.

Animals↗
PubMed2000

[Placebo].

BACKGROUND: The placebo reaction is a widely known phenomenon but the way it develops is not fully understood. This fact has given rise to numerous misinformed opinions on this subject. PLACEBO ANALGESIA: More research has been done in the field of placebo analgesia, where the involvement of the endogenous opioid systems was discovered some twenty years ago. Recently there have been some new discoveries concerning the role of expectancy and drug conditioning in experimentally induced placebo analgesia. PLACEBO REACTION: The placebo reaction is very impressive not only following drug administration, but also after surgical operations. In many cases, it is extremely difficult to decide whether a therapeutic success is due to a given medical intervention or to a placebo response. The use of placebo controlled clinical studies remains an ethically charged issue.

English Abstract↗
PubMed2000

Preliminary studies on feline coronavirus distribution in naturally and experimentally infected cats.

The shedding, tissue distribution and quasispecies composition of feline coronaviruses were studied in naturally and experimentally infected cats. The infection remained subclinical, but the majority of the animals shed the virus via faeces throughout the experiment. Sequences corresponding to the viral nucleocapsid region were amplified by reverse-transcription polymerase chain reaction from the cortex, dura mater, pancreas, lungs, third eyelid, and the heart muscle in four cases. Interestingly, the ORF7b viral region - a supposed virulence factor - was detected in fewer organs, raising the possibility that this region can be affected by deletions during virus replication in vivo. It is demonstrated that the composition of the viral quasispecies differs between organs, and that genomic regions with different functions undergo distinct processes of selection, which should be considered during the evolution of feline coronaviruses.

Animals↗
PubMed2000

Prevalence and genetic pattern of feline coronaviruses in urban cat populations.

The prevalence and phylogeny of feline coronaviruses were studied in urban cat populations by sampling of 113 clinically healthy cats. Rectal swab samples were subjected to a nested reverse-transcription polymerase chain reaction, specific for the conservative nucleocapsid region of the virus genome. More than 30% of the sampled animals proved positive for the presence of feline coronaviruses. The nucleotide sequences of amplified 440 bp products were determined, aligned and the phylogenetic analysis revealed noticeable genetic clusters among the prevalent feline coronaviruses in the surveyed geographic area. These findings will hopefully contribute to the elucidation of the epidemiology of feline infectious peritonitis.

Animals↗
PubMed2000

Allelic polymorphism of GSTM1 and NAT2 genes modifies dietary-induced DNA damage in colorectal mucosa.

Typically, cancer is caused by the interaction of genetic and environmental factors. In colorectal carcinogenesis, diet and nutritional habits are the most important external risk determinants. Allelic polymorphisms of certain metabolizing enzymes may have an influence on cancer risk by modifying the concentration of active carcinogenic compounds in the body. In the present study we investigated the interaction between nutritional and genetic susceptibility factors in human colon carcinogenesis. Healthy volunteers were divided into four groups, based on allelic polymorphisms of N-acetyltransferase 2 and glutathione-S-transferase M1 enzymes. Comet assay was used to determine the level of DNA strand breaks in exfoliated colorectal mucosal cells, following a 2-day vegetarian diet, and after switching to a 2-day 'high-meat' diet. The 'high-meat' diet statistically significantly increased the amount of single-strand breaks in rapid acetylators and among individuals with a GSMT1 + genotype, while it caused only a slight and not significant increase in the other groups. Our study emphasizes the importance of using susceptibility markers in cancer epidemiology, since environmental effects are strongly modified by these genetic factors.

Alleles↗
PubMed2000

Comparison of early onco/suppressor gene expressions in peripheral leukocytes and potential target organs of rats exposed to the carcinogen 1-nitropyrene.

An in-vivo model has been developed to study early expressions of c-myc, Ha-ras oncogenes and p53 suppressor gene as biomarkers of carcinogenic exposure and/or tumorigenesis. In order to validate the in-vivo expression changes as biomarkers, rats were treated with the outdoor air pollutant carcinogen 1-nitropyrene. The gene expression levels were measured after 24 and 48 h in potential target tissues (lung, liver, lymph nodes, kidneys, spleen) and in peripheral blood leukocytes. Another main objective was to prove the applicability of leukocytes as a surrogate tissue, having a similar expression pattern of the selected genes upon carcinogenic exposure. The c-myc oncogene was not suitable as an early biomarker because of the lack or low level of its expression. However, in the case of the other oncogene Ha-ras and the suppressor gene p53, remarkable and early changes were detected in the expression signals. Similar expression patterns could only be detected in leukocytes and the spleen; therefore we continue this validation study by using other types and routes of exposure.

Animals↗
PubMed2000

Primary structure of human matrilin-2, chromosome location of the MATN2 gene and conservation of an AT-AC intron in matrilin genes.

We isolated full-length cDNA clones for human matrilin-2, an oligomeric protein, which forms filamentous networks in the extracellular matrices of various tissues. The human matrilin-2 precursor is encoded by a 4.0-kb mRNA, it consists of 956 amino acids and shows 93% similarity to the mouse protein. Out of the two von Willebrand factor type A-like domains, the 10 epidermal growth factor-type modules, one unique sequence and the oligomerization module, the first A domain is the most conserved. RT-PCR demonstrated wide expression of the gene in human cell lines of fibroblastic or epithelial origin. Alternative splicing affected only 19 amino acids in a 75-moiety-long segment, unique to matrilin-2. Isolation and analysis of the 3' end of the gene revealed that the reason for alternative splicing is alternative 3' splice site selection. Further, we identified in the human matrilin-2 gene a U12 type AT-AC intron between the last two exons encoding the oligomerization domain. We mapped the matrilin-2 gene (MATN2) by fluorescence in situ hybridization at chromosome position 8q22.

Alternative Splicing↗