Mitochondria dysfunction is one of the causes of diclofenac toxicity in the green alga Chlamydomonas reinhardtii.

Background: Non-steroidal anti-inflammatory drugs (NSAIDs), such as diclofenac (DCF), form a significant group of environmental contaminants. When the toxic effects of DCF on plants are analyzed, authors often focus on photosynthesis, while mitochondrial respiration is usually overlooked. Therefore, an in vivo investigation of plant mitochondria functioning under DCF treatment is needed. In the present work, we decided to use the green alga Chlamydomonas reinhardtii as a model organism. Methods: Synchronous cultures of Chlamydomonas reinhardtii strain CC-1690 were treated with DCF at a concentration of 135.5 mg × L-1, corresponding to the toxicological value EC50/24. To assess the effects of short-term exposure to DCF on mitochondrial activity, oxygen consumption rate, mitochondrial membrane potential (MMP) and mitochondrial reactive oxygen species (mtROS) production were analyzed. To inhibit cytochrome c oxidase or alternative oxidase activity, potassium cyanide (KCN) or salicylhydroxamic acid (SHAM) were used, respectively. Moreover, the cell's structure organization was analyzed using confocal microscopy and transmission electron microscopy. Results: The results indicate that short-term exposure to DCF leads to an increase in oxygen consumption rate, accompanied by low MMP and reduced mtROS production by the cells in the treated populations as compared to control ones. These observations suggest an uncoupling of oxidative phosphorylation due to the disruption of mitochondrial membranes, which is consistent with the malformations in mitochondrial structures observed in electron micrographs, such as elongation, irregular forms, and degraded cristae, potentially indicating mitochondrial swelling or hyper-fission. The assumption about non-specific DCF action is further supported by comparing mitochondrial parameters in DCF-treated cells to the same parameters in cells treated with selective respiratory inhibitors: no similarities were found between the experimental variants. Conclusions: The results obtained in this work suggest that DCF strongly affects cells that experience mild metabolic or developmental disorders, not revealed under control conditions, while more vital cells are affected only slightly, as it was already indicated in literature. In the cells suffering from DCF treatment, the drug influence on mitochondria functioning in a non-specific way, destroying the structure of mitochondrial membranes. This primary effect probably led to the mitochondrial inner membrane permeability transition and the uncoupling of oxidative phosphorylation. It can be assumed that mitochondrial dysfunction is an important factor in DCF phytotoxicity. Because studies of the effects of NSAIDs on the functioning of plant mitochondria are relatively scarce, the present work is an important contribution to the elucidation of the mechanism of NSAID toxicity toward non-target plant organisms.

Long-term exposure to nicotine markedly reduces kynurenic acid in rat brain--in vitro and ex vivo evidence.

Kynurenic acid (KYNA) is a recognized broad-spectrum antagonist of excitatory amino acid receptors with a particularly high affinity for the glycine co-agonist site of the N-methyl-D-aspartate (NMDA) receptor complex. KYNA is also a putative endogenous neuroprotectant. Recent studies show that KYNA strongly blocks alpha7 subtype of nicotinic acetylcholine receptors (nAChRs). The present studies were aimed at assessing effects of acute and chronic nicotine exposure on KYNA production in rat brain slices in vitro and ex vivo. In brain slices, nicotine significantly increased KYNA formation at 10 mM but not at 1 or 5 mM. Different nAChR antagonists (dihydro-beta-erythroidine, methyllycaconitine and mecamylamine) failed to block the influence exerted by nicotine on KYNA synthesis in cortical slices in vitro. Effects of acute (1 mg/kg, i.p.), subchronic (10-day) and chronic (30-day) administration of nicotine in drinking water (100 microg/ml) on KYNA brain content were evaluated ex vivo. Acute treatment with nicotine (1 mg/kg i.p.) did not affect KYNA level in rat brain. The subchronic exposure to nicotine in drinking water significantly increased KYNA by 43%, while chronic exposure to nicotine resulted in a reduction in KYNA by 47%. Co-administration of mecamylamine with nicotine in drinking water for 30 days reversed the effect exerted by nicotine on KYNA concentration in the cerebral cortex. The present results provide evidence for the hypothesis of reciprocal interaction between the nicotinic cholinergic system and the kynurenine pathway in the brain.

Mature Luffa Leaves (Luffa cylindrica L.) as a Tool for Gene Expression Analysis by Agroinfiltration.

We exploited the potential of cucurbits for ectopic gene expression. Agroinfiltration is a simple and commonly used method to obtain transient expression of foreign genes in plants. In contrast to in vitro transformation techniques, agroinfiltration can be used for genetic modification of mature plant tissues. Although the cucurbits are commonly used as model plants for molecular biology and biotechnology studies, to date there are no literature sources on the possibility of transient gene expression in mature cucurbit tissues. Our research has shown that mature leaves of Luffa cylindrica L. (luffa), in contrast to other cucurbit species, can be successfully transiently transformed with Agrobacterium tumefaciens. We efficiently transformed luffa leaves with a reporter gene encoding ß-glucuronidase (GUS). The GUS activity in transiently transformed leaf tissues was detected within 24 h after the infiltration with bacteria. Additionally, we have shown that the activity of a transiently expressed the GUS gene can be monitored directly in the EDTA-exudates collected from the cut petioles of the agroinfiltrated leaves. The results suggest that luffa leaves can be useful as a plant expression system for studies of physiological and biochemical processes in cucurbits.

Effect of pesticides on kynurenic acid production in rat brain slices.

Kynurenic acid (KYNA) is a broad spectrum antagonist of ionotropic glutamate receptors, preferentially active at the strychnine-insensitive glycine allosteric site of the N-methyl-D-aspartate (NMDA) receptor, and a noncompetitive antagonist of alpha7 nicotinic receptor. Animal studies showed that it possesses anticonvulsant and neuroprotective properties. Its involvement in the pathophysiology of various brain disorders was suggested. In this study, the effect of pesticides on KYNA production in brain cortical slices was investigated. Pyrethroids, deltamethrin and fenpropathrin significantly lowered KYNA production. Methomyl, bensultap, fipronil, diquat and MCPA were ineffective in this regard. In view of this data, the inhibition of KYNA synthesis appear to merit further investigation as a potential factor contributing to the toxicology of pyrethroids.

Ontogenic changes of kynurenine aminotransferase I activity and its expression in the chicken retina.

Kynurenine aminotransferases are key enzymes for the synthesis of kynurenic acid (KYNA), an endogenous glutamate receptor antagonist. The study described here examined ontogenic changes of kynurenine aminotransferase I (KAT I) activity and its expression in the chicken retina. KAT I activity measured on embryonic day 16 (E16) was significantly higher than at all other stages (E12, P0 and P7). Double labeling with antibodies against glutamine synthetase showed that on P7 KAT I was expressed in Müller cell endfeet and their processes in the inner retina. Since KAT I activity is high in the late embryonic stages, it is conceivable that it plays a neuromodulatory role in the retina during the late phase of embryogenesis.

[Controversy concerning optimal prophylaxis and empirical antifungal therapy in immunocompromised patients]. / Kontrowersje dotyczace optymalnej profilaktyki i leczenia zakazen grzybami w stanach obnizonej odpornosci.

This article presents actual major problem about a steady increase in frequency of opportunistic invasive fungal infections (IFIs) in immunocompromised patients. However, there still remains much uncertainty regarding the best methods for establishing the diagnosis of most IFIs. An international consensus, that defining opportunistic IFIs proposed three levels of probability: "proven", "probable", and "possible". Practising physicians approach this uncertainty by prophylaxis and antifungal empirical therapy. Unfortunately, up to now we dispose only few antifungals compounds and all have narrow of therapeutic windows. This article reviews the therapeutic options in chemoprevention and antifungal therapy. Fluconazole and itraconazole are the first durable alternatives to polyenes in chemoprophylaxis. However their use remains controversial as debate continues over both their effectiveness and their potential to select out resistant Candida sp. Amphotericin B is the "gold" standard for the treatment both empirical and proven IFIs, but this drug is frequently associated with severe nephrotoxicity. The lipid formulations of amphotericin B enable higher dosages to be administrated with lower incidences of side effects but its effectiveness is not sufficient. It is to be hoped that rationally designed clinical trials with the new compounds, such as for example echinocandins will lead to improved prevention and treatment of IFIs.

[Polymorphism at the glutathione S-transferase pi locus as a risk factor for ifosfamide nephrotoxicity in children]. / Polimorfizm genu kodujacego transferaze S-glutationowa klasy P1 jako czynnik ryzyka nefrotoksycznego dzialania ifosfamidu u dzieci.

The aim of the study was an assessment of various risk factors for nephrotoxicity of ifosfamide (IF) in children taking into account the importance of the concentrations of toxic metabolites of the drug excreted with urine and the polymorphism of genes encoding S-glutathione transferases of mi, pi, and theta classes (GSTM1, GSTP1 and GSTT1). The study was carried out in 37 children aged 2-17 years (mean age 8.9 +/- 4.5 years) treated with IF in 3 g/m2 dose for various malignant diseases. For the assessment of the incidence of deletion of GSTM1 and GSTT1 genes PCR method was applied while in the case of GSTP1 gene the polymorphism of A-G codon 105 was detected by the PCR-RFLP method. Before and after each treatment cycle the cumulative ifosfamide dose was calculated and the biochemical indices of renal canalicular and glomerular function were assessed which were graduated according to extended WHO criteria. Additionally, nuclear magnetic resonance 31P NMR method was applied for calculation of the concentrations of ifosfamide nephrotoxic metabolites and of the unchanged drug excreted with urine. The analysis performed demonstrated that in children with GSTP1 gene A-G codon 105 transition, a statistically significantly (p = 0.01) higher urinary excretion of toxic ifosfamide metabolites occurred, that increased with the cumulative drug dose. The age, sex and deletions of GSTM1 and GSTT1 genes exerted no effect on the concentrations of the toxic metabolites excreted with urine. The results of the studies demonstrate that GSTP1 gene mutations are the genetic risk factor for nephrotoxic complications of ifosfamide use.

[Urinary tract infections in children under three years of age]. / Zakazenia ukladu moczowego u dzieci do 3 roku zycia.

Urinary tract infection (UTI) in infants and babies is still a challenging problem. The aim of the study was the clinical analysis of children under three years of age with UTI, hospitalised in The Department of Paediatrics, Medical University of Lodz in 2000-2001. The study included 91 children (45 girls and 46 boys), aged 1-36 months; 10 months on the average. Acute UTI was observed in 29% of children, recurrent UTI was diagnosed in 71% of patients. Voiding cystography was performed in 82% of children. Among 28/91 cases of vesicoureteral reflux, 36% were unilateral and 64% were bilateral. Vesicoureteral reflux grade 2 was most frequent (64%) in patients with UTI. The most common pathogen was Escherichia coli. The obtained results demonstrate the necessity of early imaging diagnosis of the urinary system in infants and babies with UTI. Patients under three years of age with UTI require hospitalisation and performance of early diagnostic examinations of the urinary tract.

The correlation analysis of WWOX expression and cancer related genes in neuroblastoma- a real time RT-PCR study.

Neuroblastoma is one of the most common paediatric cancers, described as unpredictable due to diverse patterns of behaviour. WWOX is a tumour suppressor gene whose expression is reduced in many tumour types. Loss of its expression was shown to correlate with more aggressive disease stage and mortality rate. The aim of this study was to investigate the role of the WWOX tumour suppressor gene in neuroblastoma formation. We performed real-time RT-PCR to analyse levels of WWOX expression in 22 neuroblastic tumour samples in correlation with genes involved in cell cycle regulation (CCNE1, CCND1), proliferation (MKI67), apoptosis (BCL2, BIRC5, BAX) and signal transduction (EGFR, ERBB4). We also evaluated two potential mechanisms - promoter methylation (MethylScreen method) and loss of heterozygosity (LOH) status, which could be connected with regulation of WWOX gene expression. We found a positive correlation between WWOX gene and BCL2 and HER4 JM-a and negative with cyclin D1 and E1. Our observations are consistent with previous findings and emphasise the role of WWOX in cell cycle and apoptosis regulation. Moreover, strong positive association with HER4 JM-a in this tumour type may indicate a role for WWOX in neuroblastoma cell differentiation. The presented results indicate that LOH in locus D16S3096 (located in intron 8) may be involved in the regulation of WWOX mRNAexpression. However, no association between methylation status of WWOX promoter and its expression was observed.

Genetic alterations of WWOX in Wilms' tumor are involved in its carcinogenesis.

Loss of heterozygosity (LOH) in 16q appears in ~20-30% cases of Wilms' tumor. Within this region, known as common fragile site FRA16D, the WWOX tumor suppressor gene is located. Abnormalities of WWOX gene expression levels were observed in many tumor types and were associated with worse prognosis. The purpose of this study was to investigate the role of the WWOX tumor suppressor gene in Wilms' tumor samples. We evaluated the correlation between expression of WWOX and genes involved in proliferation (Ki67), apoptosis (BCL2, BAX), signal transduction (ERBB4, ERBB2, EGFR), cell cycle (CCNE1, CCND1), cell adhesion (CDH1) and transcription (TP73) using real-time RT-PCR in 23 tumor samples. We also analyzed the potential causes of WWOX gene expression reduction i.e., promoter methylation status (MethylScreen method) and loss of heterozygosity (LOH) status. We revealed a positive correlation between WWOX expression and BCL2, BCL2/BAX ratio, EGFR, ERBB4 isoform JM-a, TP73 and negative correlation with both cyclins. Loss of heterozygosity of the WWOX gene was observed only at intron 8, however, it had no influence on the reduction of its expression levels. Contrary to LOH, methylation of the region covering the 3' end of the promoter and part of exon 1 was associated with statistically significant reduction of WWOX gene expression levels. In the present study we reveal that in Wilms' tumors the WWOX expression levels are positively associated with the process of apoptosis, signal transduction through the ErbB4 pathway and EGFR and negatively with the regulation of the cell cycle (by cyclin E1 and D1). Moreover, our analysis indicates that in this type of tumor the expression of the WWOX gene can be regulated by an epigenetic mechanism--its promoter methylation.

NMDA antagonists exert distinct effects in experimental organophosphate or carbamate poisoning in mice.

Organophosphate (OP) and carbamate acetylcholinesterase (AChE) inhibitors produce seizures and lethality in mammals. Anticonvulsant and neuroprotective properties of N-methyl-D-aspartate (NMDA) antagonists encourage the investigation of their effects in AChE inhibitor-induced poisonings. In the present study, the effects of dizocilpine (MK-801, 1 mg/kg) or 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 10 mg/kg), alone or combined with muscarinic antagonist atropine (1.8 mg/kg), on convulsant and lethal properties of an OP pesticide dichlorvos or a carbamate drug physostigmine, were studied in mice. Both dichlorvos and physostigmine induced dose-dependent seizure activity and lethality. Atropine did not prevent the occurrence of convulsions but decreased the lethal effects of both dichlorvos and physostigmine. MK-801 or CPP blocked or attenuated, respectively, dichlorvos-induced convulsions. Contrariwise, NMDA antagonists had no effect in physostigmine-induced seizures or lethality produced by dichlorvos or physostigmine. Concurrent pretreatment with atropine and either MK-801 or CPP blocked or alleviated seizures produced by dichlorvos, but not by physostigmine. Both MK-801 and CPP co-administered with atropine enhanced its antilethal effects in both dichlorvos and physostigmine poisoning. In both saline- and AChE inhibitor-treated mice, no interaction of the investigated antidotes with brain cholinesterase was found. The data indicate that both muscarinic ACh and NMDA receptor-mediated mechanisms contribute to the acute toxicity of AChE inhibitors, and NMDA receptors seem critical to OP-induced seizures.

[Increased urinary excretion of the neurotoxic side-chain metabolites of ifosphamide in children with polymorphism of the glutathione S-transferases genes]. / Zwiekszone dobowe wydalanie neurotoksycznych metabolitów ifosfamidu u dzieci z dziedziczonym polimorfizmem genów kodujacych transferazy S-glutationu.

UNLABELLED: From 5% to 30% of children treated with ifosphamide (IF) develop symptoms of neurotoxicity due to toxic metabolites of the drug: 2- and 3- dechloroifosphamide (2- and 3-DCIF) and chloracetaldehyde (CAA), which cause glutathione depletion in cells. The aim of the study is to establish the influence of polymorphism of genes encoding for glutathione S-transferases classes pi (GSTP1), mi (GSTM1) and theta (GSTT1) on frequency of neurotoxicity of IF and amounts of toxic metabolites of the drug excreted in urine. MATERIAL AND METHODS: Neurotoxicity of IF was assessed in 76 children (38 girls and 38 boys), aged 9 to 210 months with diffrent kinds of neoplasms. They were treated with IF in 3-hours infusion in doses from 1.5 g/m2 to 3 g/m2 for 3 to 5 days. Before chemotherapy, deletions of GSTT1, GSTM1 genes and transition at +313 A-G in GSTP1 gene were identified with PCR and PCR-FRLP method, respectively. Daily urine excretion of 2-DCIF, 3-DCIF and unmetabolised IF was assessed with nuclear magnetic resonance (31P NMR). RESULTS: Symptoms of neurotoxicity were observed in 14 (18%) of 76 examined children treated with IF Comparing to children without neurological symptoms, in children with encephalopathy urinary excretion of unchanged ifosphamide was lower (p=0.055) and 2DCIF and 3DCIF was increased. Concomitantly, in children with transition at 313 A-->G GSTP1 gene concentrations of 2DCIF and 3DCIF were increased. Excretion of unmetabolised IF was statistically significantly higher in children with deletion of GSTT1 gene (p=0.02). Moreover, no correlation was found between the GSTM1 genotype and the excretion of ifosphamide and its metabolites. CONCLUSION: The results suggest that ifosphamide can be the substrate for glutathione S-transferases. Polymorphism of genes coding for glutathione S-transferases can influence individual reactions to iphosphamide.

Are seeds suitable for flow cytometric estimation of plant genome size?

BACKGROUND: Nuclear DNA content in plants is commonly estimated using flow cytometry (FCM). Plant material suitable for FCM measurement should contain the majority of its cells arrested in the G0/G1 phase of the cell cycle. Usually young, rapidly growing leaves are used for analysis. However, in some cases seeds would be more convenient because they can be easily transported and analyzed without the delays and additional costs required to raise seedlings. Using seeds would be particularly suitable for species that contain leaf cytosol compounds affecting fluorochrome accessibility to the DNA. Therefore, the usefulness of seeds or their specific tissues for FCM genome size estimation was investigated, and the results are presented here. METHODS: The genome size of six plant species was determined by FCM using intercalating fluorochrome propidium iodide for staining isolated nuclei. Young leaves and different seed tissues were used as experimental material. Pisum sativum cv. Set (2C = 9.11 pg) was used as an internal standard. For isolation of nuclei from species containing compounds that interfere with propidium iodide intercalation and/or fluorescence, buffers were used supplemented with reductants. RESULTS: For Anethum graveolens, Beta vulgaris, and Zea mays, cytometrically estimated genome size was the same in seeds and leaves. For Helianthus annuus, different values for DNA amounts in seeds and in leaves were obtained when using all but one of four nuclei isolation buffers. For Brassica napus var. oleifera, none of the applied nuclei isolation buffers eliminated differences in genome size determined in the seeds and leaves. CONCLUSIONS: The genome size of species that do not contain compounds that influence fluorochrome accessibility appears to be the same when estimated using specific seed tissues and young leaves. Seeds can be more suitable than leaves, especially for species containing staining inhibitors in the leaf cytosol. Thus, use of seeds for FCM nuclear DNA content estimation is recommended, although for some species a specific seed tissue (usually the radicle) should be used. Protocols for preparation of samples from endospermic and endospermless seeds have been developed.

Role of GSTM1, GSTP1, and GSTT1 gene polymorphism in ifosfamide metabolism affecting neurotoxicity and nephrotoxicity in children.

The aim of this study was to evaluate the impact of GSTM1, GSTT1, and GSTP1 gene polymorphism on urinary excretion of unchanged ifosfamide, 2-dechloroethylifosfamide (2DCIF), and 3-dechloroethylifosfamide (3DCIF) with regard to the incidence of ifosfamide-related nephrotoxicity and neurotoxicity in children. The study comprised 76 children (38 girls, 38 boys) ages 9.84 to 210 months who were being treated for various malignant diseases with ifosfamide. The children were enrolled after identification of genotype coding for three classes of glutathione S-transferases (GSTM1, GSTT1, and GSTP1) at the initial stage of diagnosis. (P) nuclear magnetic resonance spectroscopy was used to analyze the urinary excretion of unchanged ifosfamide, 2DCIF, and 3DCIF metabolites on consecutive days after the end of the 3-hour infusion of ifosfamide. In children with polymorphic locus of the GSTP1 gene compared with children with homozygous wild alleles, increased urinary excretion of 3DCIF (P=0.029) and decreased creatinine clearance was found (Mann-Whitney P=0.03; median 81.1 mL/min/1.73 m vs. 105.0 mL/min/1.73 m, respectively). The authors' multidimensional analysis model revealed that besides the total ifosfamide dose and co-administration of other toxic drugs, polymorphic locus of GSTP1 gene may be one of the factors determining a higher toxicity of the cytostatic agent. The model was construed at P=0.029. Moreover, no correlation was found between the GSTM1 or GSTT1 genotype and ifosfamide toxicity and the urinary excretion of its metabolites. The results of this analysis indicate that individual reactions to ifosfamide can depend on inherited genetic polymorphisms, especially associated with the GSTP1 gene coding detoxifying enzyme.

[Prognosis of clinical course of primary brain tumours in children in relationship to the duration and characteristic features of initial clinical symptoms]. / Prognozowanie przebiegu klinicznego pierwotnych guzów mózgu u dzieci w odniesieniu do dlugosci trwania i charakteru wstepnych objawów klinicznych.

UNLABELLED: Primary tumours of the central nervous system belong to the most frequently occurring neoplastic diseases in paediatric patients. During the initial phase of disease development, the clinical symptoms of brain tumours might suggest disorders of other organs and their diagnosis is frequently delayed in relation to therapeutic possibilities. The aim of the study was to analyse the characteristic features and duration of preliminary symptoms arising due to brain tumours in paediatric patients treated in a single centre and to try to assess their prognostic significance for recurrence and death. MATERIAL AND METHODS: We performed a retrospective assessment of the characteristic features of preliminary symptoms of brain tumours in 81 paediatric patients (45 female, 35 male) in the age range of 1.5 month - 17.2 years. Those characteristic features included the duration of symptoms until diagnosis (Pre-Diagnostic Symptoms Interval, PSI) and their correlation with the tumour type, its localization and size at the moment of diagnosis. RESULTS: The mean duration of symptoms in the studied group was 3 months. In nearly 45% of patients PSI was longer then 3 months and in 17,5% it was over 6 months. The predominant preliminary disease symptoms were the symptoms of increased intracranial pressure (n=56, 69,1%) The longer PSI correlated with the disease recurrence rate (p=0.024) and death rate (p=0.04). When PSI was longer then 6 months, all the tumours diagnosed were larger then 30 mnm, however no relationship was found between PSI duration and the tumor size (p=0.35). There was no correlation between the tumour size and the frequency of death (p=0.8), but in patients with tumours smaller then 30 mm in their greatest dimension, the recurrence of the neoplastic process was more frequent. CONCLUSIONS: Duration of preliminary symptoms may have an effect on the tumour recurrence and on the rate of death in paediatric patients with brain tumours. Early diagnosis plays an evident role in prognosis.

Analysis of the urinary excretion of ifosfamide and its N-dechloroethylated metabolites in children using 31P-NMR spectroscopy.

Amounts of ifosfamide (CAS 3778-73-2) and its N-dechloroethylated metabolites excreted in the urine were measured using 31P-NMR spectroscopy in 26 cancer children treated with this drug. Strong inter-patient variation in levels of these compounds were found. These differences were independent from patients age, body surface area, and sex, the dose of the drug, suggesting genetic base of observed variations in ifosfamide metabolism.

Polymorphism within the glutathione S-transferase P1 gene is associated with increased susceptibility to childhood malignant diseases.

BACKGROUND: Glutathione S-transferases (GSTs) are involved in the metabolism of carcinogens and anticancer drugs. Functional polymorphisms exist in at least three genes that code for the GSTs, such as the GSTM1 and GSTT1 gene deletions or the A-G transition within the GSTP1 gene, which represents distinct GSTP1a and GSTP1b alleles. In the present case-control study, we aimed at estimation of the relationship between the GSTM1, GSTT1, and GSTP1 genotypes and the susceptibility to various types of childhood malignancies and the early relapses of diseases. PROCEDURE: Using the polymerase chain reaction on the DNA extracted from peripheral blood leukocytes, we identified the GSTM1, GSTT1, and GSTP1 genotypes in 234 children at the initial stage of a childhood malignancy as well as in 460 age-and sex-matched healthy subjects who served as controls. The follow-up period for the effects of the anticancer therapy ranged from 11 to 43 months. RESULTS: Compared to the controls, a significant increase in the frequency of the GSTP1b/GSTP1b genotype (odds ratio (OR) 5.7; 95% confidence limit (CL) from 2.4 to 13.8; Pearsons Chi-square P = 0.0001) was detected in the children with neoplasms. The GSTM1 and GSTT1 genotypes did not show any correlation with the risk of the de novo diagnosed neoplasms. During the observation, 62 children (26%) were found to be present with a local or disseminated recurrence of the diseases. The analysis indicated a trend in increasing risk of relapse for carriers of the GSTP1a allele (OR = 3.29; 95% CL from 0.73 to 14.67 P = 0.03). CONCLUSIONS: Our results support the hypothesis that GST genotype affects etiology and outcome of a variety of childhood malignancies.

[Increased frequency of A-G transition at exon 5 of GSTP1 as a genetic risk factor for acute childhood leukaemia]. / Zwiekszona czestosc tranzycji A-G eksonu genu GSTP1 jako genetyczny cynnik ryzyka podatnosci na ostre bialaczki wieku dzieciecego. Doniesienie I.

UNLABELLED: Polymorphism of genes encoding glutathione S-transferases GSTM1, GSTT1 GSTP1 is one of the genetic predictors of susceptibility to cancers in the adults. The frequency of deletions of GSTM1. GSTT1 genes and transition A-G in GSTP1 gene were taken into consideration. THE AIM of this study was to investigate the role of GST genes polymorphisms as a genetic risk factor for acute lymphoblastic leukaemia (ALL), and to study the relationship of these polymorphisms with clinical outcome in childhood leukaemias. MATERIAL AND METHODS: 86 children with newly diagnosed acute leukaemia (female: male ratio = 37:49. median age = 7.8 years) and 460 healthy controls were examined using the PCR and PCR-RFLP methods to identify polymorphisms within GSTM1, GSTT1 and GSTP1 genes. In the group of children with ALL. the frequency of relapses, deaths, clinical course, immunophenotype of blasts and the initial response to prednisone were also analyzed. RESULTS: the higher frequency of A-G transition in the GSTP1 gene was identified in the group of children with ALL in comparison to healthy controls (OR=3.13, 95%CI=1.4-7). We also found that the combination of GSTPl (Val/Val) and GSTM1 null genotypes further increased the risk of ALL (OR= 10.63, 95%CI=3.47 - 32.58; p =0.0001). No differences in the frequency of GSTM1 and GSTTI genes between both groups (OR=1; 95%CI=0,59-1,74 and OR=0, 71; 95%CI=0.45-1.13 respectively) were observed. Statistical analysis has not revealed any connections between polymorphisms within glutathione S-transferases genes and the frequency of relapses and death or poor initial response to prednisone. However, the biphenotypic immunophenotype or B-line blasts were the risk factors of relapse or death of progression in ALL (p=0.03). CONCLUSION: transition in exon 5 of GSTP1 gene (alone or combined with GSTM1 deletion) may be one of the molecular predictors of higher susceptibility to acute leukaemia in children. but not of the clinical course of this disease.

Deficit of endogenous kynurenic acid in the frontal cortex of rats with a genetic form of absence epilepsy.

The present studies sought to determine the concentrations of endogenous kynurenic acid (KYNA) and to measure the activity of kynurenine aminotransferases (KAT) I and II in the discrete brain regions of 3- and 6-month old WAG/Rij rats, a genetic model of absence epilepsy. Analogues experiments were performed using age-matched ACI rats, which served as a non-epileptic control. The age-dependent increase in KYNA concentration in the frontal cortex of WAG/Rij rats was considerably reduced in comparison to what was found in ACI rats. Consequently, the concentration of KYNA in the frontal cortex of epileptic rats was significantly lower than in non-epileptic controls. There were no such strain differences in other brain regions. The activities of KAT I and II also showed age-dependent increase with an exception for KAT II in the frontal cortex. Our data suggest that selective deficits of endogenous KYNA may account for increased excitability in the frontal cortex, which in turn may lead to the development of spontaneous spike-wave discharges in WAG/Rij rats.

Down-regulation of DELLA genes is not essential for germination of tomato, soybean, and Arabidopsis seeds.

The relationship between expression of a negative regulator of GA signal transduction (RGL2) belonging to the DELLA gene family and repression of Arabidopsis seed germination has been studied (Lee S, Cheng H, King KE, Wang W, He Y, Hussain A, Lo J, Harberd NP, Peng J [2002] Genes and Development 16: 646-658). There is one DELLA gene (LeGAI) present in tomato (Lycopersicon esculentum Mill.), which is expressed in both vegetative and reproductive tissues. During germination of wild-type tomato seed, there was no decline in the expression of LeGAI in either the embryo or the endosperm. Rather, LeGAI transcripts increased in these tissues following imbibition and remained high during and following germination. A similar increase in LeGAI transcripts occurred in the endosperm and embryo of GA-treated gib-1 mutant seed during and following germination. Likewise in soybean (Glycine max) seed, there was no decline in the expression of two DELLA genes in the radicle before or after germination. Upon reexamination of RGL2 in Arabidopsis seeds, a decline in its expression was noted but only after radicle emergence, i.e. after germination had been completed. Taken together, these data are consistent with GA-induced down-regulation of DELLA genes not being a prerequisite for germination of tomato, soybean, and Arabidopsis seeds.