PDE10A and PDE10A-dependent cAMP catabolism are dysregulated oppositely in striatum and nucleus accumbens after lesion of midbrain dopamine neurons in rat: a key step in parkinsonism physiopathology.

Loss of dopamine neurons in experimental parkinsonism results in altered cyclic nucleotide cAMP and cGMP levels throughout the basal ganglia. Our objective was to examine whether expression of phosphodiesterase 10A (PDE10A), an isozyme presenting a unique distribution in basal ganglia, is altered after unilateral injection of 6-hydroxydopamine in the medial forebrain bundle, eliminating all midbrain dopaminergic neurons, such that cyclic nucleotide catabolism and steady state could be affected. Our study demonstrates that PDE10A mRNA levels were decreased in striatal neurons 10 weeks after 6-hydroxydopamine midbrain lesion. Such changes occurred in the striatum ipsilateral to lesion and were paralleled by decreased PDE10A protein levels and activity in striatal neurons and in striato-pallidal and striato-nigral projections. However, PDE10A protein and activity were increased while PDE10A mRNA was unchanged in the nucleus accumbens ipsilateral to the 6-hydroxydopamine midbrain lesion. Accordingly, cAMP levels were down-regulated in the nucleus accumbens, and up-regulated in the striatum ipsilateral to the lesion, but they were not significantly changed in substantia nigra and globus pallidus. Unlike cAMP, cGMP levels were decreased in all dopamine-deafferented regions. The opposite variations of cAMP steady state in striatum and nucleus accumbens are concordant and likely dependent, at least in part, on the down-regulation of PDE10A expression and activity in the former and its up-regulation in the latter. On the other hand, the down-regulation of cGMP steady state in the striato-nigral and striato-pallidal complex is not consistent with and is likely independent from the concomitant down-regulation of PDE10A. Therefore, dopamine loss inversely regulates PDE10A gene expression in the striatum and PDE10A post-transcription in the nucleus accumbens, therein differentially modulating PDE10A-dependent cAMP catabolism.

Hearing and cognitive impairment: a functional evaluation of associative brain areas in patients affected by Alzheimer's disease.

Auditory dysfunction observed in patients with cognitive diseases is probably due to the alteration of some brain areas involved in sound stimulus processing. The present study aimed to investigate differences in such processing and in connectivity of the primary auditory cortex in patients affected by Alzheimer's disease (AD) and in normal subjects. We examined 131 diagnosed AD patients and a control group (CG) of 36 normal subjects. After a complete clinical investigation, focused on hearing function, all subjects underwent a brain FDG PET/CT. AD subjects vs CG showed reduced glucose consumption in BA 6,7,8,39, whereas we did not find differences in the primary auditory cortex. In AD, connectivity analyses showed a positive correlation of the primary auditory cortex with BA 6,8,21,31,39,40,42 and a negative correlation with BA 19, cerebellum and basal ganglia. Our findings suggest that neurological evaluation of patients with hearing loss might allow earlier (preclinical) identification of those affected by cognitive impairment.

Lowered cAMP and cGMP signalling in the brain during levodopa-induced dyskinesias in hemiparkinsonian rats: new aspects in the pathogenetic mechanisms.

Dysregulation of dopamine receptors is thought to underlie levodopa-induced dyskinesias in experimental models of Parkinson's disease. It is unknown whether an imbalance of the second messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), is involved in the alterations of levodopa/dopamine signal transduction. We examined cAMP and cGMP signalling in the interconnected cortico-striatal-pallidal loop at the peak of levodopa-induced dyskinesias in rats with 6-hydroxydopamine lesions in the substantia nigra. In addition, we examined the role of phosphodiesterase (PDE) and the rate of cAMP and cGMP degradation on the severity of levodopa-induced dyskinesias in animals pretreated with PDE inhibitor, zaprinast. Unilateral lesion of substantia nigra led to an increase in cAMP but a decrease in cGMP levels in the ipsilateral basal ganglia. After chronic levodopa treatment, cAMP and cGMP were differentially regulated in eukinetic animals: the cAMP level increased in the cortex and striatum but decreased in the globus pallidus of both hemispheres, whereas the cGMP decreased below baseline levels in the contralateral cortico-striatal-pallidal regions. In dyskinetic animals chronic levodopa treatment led to an absolute decrease in cAMP and cGMP levels in cortico-striatal-pallidal regions of both hemispheres. Pretreatment with zaprinast reduced the severity of levodopa-induced dyskinesias, and partly prevented the decrease in cyclic nucleotides compared with pretreatment with saline-levodopa. In conclusion, using a rat model of hemiparkinsonism, we observed a significant reduction in the levels of cyclic nucleotides in both hemispheres at the peak of levodopa-induced dyskinesias. We propose that such a decrease in cyclic nucleotides may partly result from increased catabolism through PDE overactivity.

Sub-cellular localization of manganese in the basal ganglia of normal and manganese-treated rats An electron spectroscopy imaging and electron energy-loss spectroscopy study.

We have studied at the ultrastructural level the presence of manganese (Mn) in rat basal ganglia, which are target regions of the brain for Mn toxicity. The rats underwent a moderate level of Mn exposure induced per os for 13 weeks. Mn was detected by means of electron spectroscopy imaging (ESI) and electron energy-loss spectroscopy (EELS) analyses on perfusion fixed samples embedded in resin. While no significant contamination by exogenous Mn occurred during the processing procedures, less than 50% of endogenous Mn was lost during fixation and dehydration of the brain samples. The residual Mn ions in the samples appeared as discrete particles, localized in selected sub-cellular organelles in a cell, suggesting that no significant translocation had occurred in the surrounding area. In control rats, the Mn sub-cellular localization and relative content were the same in neurons and astrocytes of rat striatum and globus pallidus: the Mn level was highest in the heterochromatin and in the nucleolus, intermediate in the cytoplasm, and lowest in the mitochondria (p<0.001). After chronic Mn treatment, while no ultrastructural damage was detected in the neurons and glial cells, the largest rate of Mn increase was noted in the mitochondria of astrocytes (+700%), an intermediate rate in the mitochondria of neurons (+200%), and the lowest rate in the nuclei (+100%) of neurons and astrocytes; the Mn level in the cytoplasm appeared unchanged. EELS analysis detected the specific spectra of Mn L(2,3) (peak at DeltaE = 665 eV) in such organelles, confirming the findings of ESI. Although a consistent loss of Mn occurred during the processing of tissue samples, ESI and EELS can be useful methods for localization of endogenous Mn in embedded tissues. The high rate of Mn sequestration in the mitochondria of astrocytes in vivo may partly explain the outstanding capacity of astrocytes to accumulate Mn, and their early dysfunction in Mn neurotoxicity. The high level of Mn in the heterochromatin and nucleoli of neurons and astrocytes in basal conditions and its further increase after Mn overload should provide insight into new avenues of investigating the role of Mn in the normal brain and a baseline for future Mn toxicity studies.

Manganese intoxication decreases the expression of manganoproteins in the rat basal ganglia: an immunohistochemical study.

Manganese (Mn) is a cofactor for some metalloprotein enzymes, including Mn-superoxide dismutase (Mn-SOD), a mitochondrial enzyme predominantly localized in neurons, and glutamine synthetase (GS), which is selectively expressed in astroglial cells. The detoxifying effects of GS and Mn-SOD in the brain, involve catabolizing glutamate and scavenging superoxide anions, respectively. Mn intoxication is characterized by impaired function of the basal ganglia. However, it is unclear whether regional central nervous system expression of manganoproteins is also affected. Here, we use immunocytochemistry in the adult rat brain, to examine whether Mn overload selectively affects the expression of GS, Mn-SOD, Cu/Zn-SOD, another component of the SOD family, and glial fibrillary acid protein (GFAP), a specific marker of astrocytes. After chronic Mn overload in drinking water for 13 weeks, we found that the number and immunostaining intensity of GS- and Mn-SOD-positive cells was significantly decreased in the striatum and globus pallidus, but not in the cerebral frontal cortex. In addition, we found that GS enzymatic activity was decreased in the strio-pallidal regions but not in the cerebral cortex of Mn-treated animals. In contrast, Cu/Zn-SOD- and GFAP-immunoreactivity was unchanged in both the cerebral cortex and basal ganglia of Mn-treated rats. Thus, we conclude that in response to chronic Mn overload, a down-regulation of some manganoproteins occurs in neurons and astrocytes of the striatum and globus pallidus, probably reflecting the vulnerability of these regions to Mn toxicity.

Oligodendrocytes express P2Y12 metabotropic receptor in adult rat brain.

In the CNS, nucleotide receptors termed P2 receptors are identified on neurons and glial cells, mediating neuron-neuron, glia-glia and glia-neuron communication. In the present work, we qualify in vivo in the adult rat CNS the cellular/subcellular distribution of P2Y12 receptor protein in cerebral cortex, white matter and subcortical nuclei (striatum and substantia nigra), by means of immunofluorescence-confocal, electron microscopy and Western blot analysis. P2Y12 receptor immunoreactivity colocalizes neither with markers such as neuronal nuclei, neurofilament light chain, calbindin and tyrosine hydroxylase, nor with glial fibrillary acidic protein and isolectin B4, but with myelin basic protein and the oligodendrocyte marker RIP, in both cell bodies and processes, indicating therefore oligodendrocyte localization. Electron microscopy identifies P2Y12 receptors in both the perikaryon and under the plasmalemma of oligodendrocyte cell bodies and radiating processes, until the paranodal region of fibers. By Western blot analysis, P2Y12 receptor shows a specific band of 42-44 kDa, matching the molecular mass predicted from amino acid sequencing. Since in platelets P2Y12 receptor is known to regulate adhesion/activation and thrombus growth/stability, from our results we could speculate by analogy that, in oligodendrocytes, P2Y12 receptor signaling might contribute to the migration and adhesion of the glial processes to axons to be myelinated.

Lymph node metastases displaying lower Ki-67 immunostaining activity than the primary breast cancer.

UNLABELLED: The aim of the study was to verify by Ki-67 immunostaining if any difference exists in the cell proliferating fraction between primary breast tumors (PTs) and matching positive axillary lymph nodes (ALNs). PATIENTS AND METHODS: Immunohistochemistry with the monoclonal antibody against Ki-67 was performed in 160 node-positive breast carcinomas and in their respective lymph node metastases. RESULTS: An increase of Ki-67 immunoreactive cells in ALN compared with that of PTs was observed in 84% of cases (ALN: mean 17%, PTs: mean 8%; p < 0.001), whereas 16% of the cases showed Ki-67 value two to six times lower in the ALNs than in the corresponding PTs (ALN: mean 3.2%, PTs mean 12.5%; p < 0.005). The decrease of Ki-67 positive cells in the ALN was independent from the histotype and the histological grade of the tumor. CONCLUSION: A different cell proliferation fraction between PTs and matching positive ALNs was demonstrated and underlined that the existence of a group of patients with decreased number of Ki-67 immunoreactive cells in lymph node metastases compared with that of the primary tumors could be taken into account in the choice of therapeutic strategy.

Difference in Ki67 and thymidylate synthase expression in primary tumour compared with metastatic nodes in breast cancer patients.

Breast cancer is a heterogeneous disease, so therapeutic predictive biological markers need to be identified. To date an accurate evaluation of predictive markers is mainly done at the primary site; however, the main goal of adjuvant therapy for breast cancer is the control of micrometastases. The aim of this study is to assess as therapeutic and/or prognostic marker, the proliferation status of primary tumors and involved nodes as measured by Ki67 and thymidylate synthase (TS) expression, in 30 breast cancer node positive patients. TS is the main target of 5-fluorouracil (5-FU) activity, and its overexpression is one of the mechanisms of 5-FU drug resistance; however, in some studies its absence is responsible for a worse response to 5-FU. Our results show that malignant cells of involved nodes were in a post mitotic phase of the cell cycle, and show a low proliferation index and TS expression, while the primary tumours and controls, were strongly positive. On these basis we can hypothesize that these cells could be less sensitive to 5-FU. Further studies are necessary to identify other mechanisms responsible for their metastasing capability and/or for their aggressiveness.

Epithelial cells up-regulate matrix metalloproteinases in cells within the same mammary carcinoma that have undergone an epithelial-mesenchymal transition.

A metastatic rat mammary carcinoma cell line, BC1, contains cells that have retained epithelial differentiation characteristics and metaplastic cells that have undergone an epithelial-mesenchymal transition. These two subpopulations cooperate to degrade collagen. We have used novel PCR assays to quantitate, for the first time, absolute levels of the mRNAs encoding matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in cell and tumor samples. BC1 tumors expressed high levels of the collagenase-3, TIMP-2, stromelysin-1, and gelatinase B genes and low levels of the stromelysin-2 and TIMP-1 genes. This pattern of expression was repeated in cultures of BC1 and cultures containing mixed clones of epithelial cells and metaplastic cells. In both BC1 and the biclonal cultures, metaplastic cells were the main source of collagenase-3, stromelysin-1 and stromelysin-2, whereas TIMPs were equally distributed and epithelial cells were the main source of gelatinase B. High levels of all four MMP mRNAs in metaplastic cells were dependent on coculture with epithelial cells, suggesting the production of an inducing factor by the epithelial cells. In contrast, gelatinase B mRNA was produced at a high level by epithelial cells in the absence of metaplastic cells. TIMP-2 mRNA was abundant in both subpopulations grown alone and did not change substantially upon coculture. Thus, the interclonal cooperativity to degrade collagen in BC1 cells required the induction of MMPs in metaplastic cells by epithelial cells. Interclonal cooperativity may be important to the progression of neoplastic tumors, a feature of which is phenotypic heterogeneity.

Activation of beta1-adrenoceptors excites striatal cholinergic interneurons through a cAMP-dependent, protein kinase-independent pathway.

The role of noradrenergic neurotransmission was analyzed in striatal cholinergic interneurons. Conventional intracellular and whole-cell patch-clamp recordings were made of cholinergic interneurons in rat brain slice preparations. Bath-applied noradrenaline (NA) (1-300 microm) dose-dependently induced both an increase in the spontaneous firing activity and a membrane depolarization of the recorded cells. In voltage-clamped neurons, an inward current was induced by NA. This effect was not prevented by alpha-adrenoceptor antagonists, whereas it was mimicked by the beta-adrenoceptor agonist isoproterenol and blocked by the beta1 antagonists propranolol and betaxolol. Interestingly, forskolin, activator of adenylate cyclase, mimicked and occluded the membrane depolarization obtained at saturating doses of both dopamine and NA. Accordingly, SQ22,536, a selective adenylate cyclase inhibitor, reduced the response to NA. Analysis of the reversal potential of the NA-induced current did not provide homogeneous results, indicating the involvement of multiple membrane conductances. Because cAMP is known to modulate Ih, the effects of ZD7288, a selective inhibitor of Ih current, were examined on the NA-induced membrane depolarization/inward current. ZD7288 mostly reduced the response to NA. However, both KT-5720 and H-89, selective protein kinase A (PKA) blockers, failed to prevent the excitatory action of NA. Likewise, calphostin C, antagonist of PKC, genistein, inhibitor of tyrosine kinase, and 8-Bromo-cGMP, blocker of PKG, did not affect the response to NA. Finally, double-labeling experiments combining beta1-adrenoceptor and choline acetyltransferase immunocytochemistry by means of confocal microscopy revealed a strong beta1-adrenoceptor labeling on cholinergic interneurons. We conclude that NA depolarizes striatal cholinergic interneurons via beta1-adrenoceptor activation, through a cAMP-dependent but PKA-independent mechanism.

Solubilization, gel filtration and sedimentation behaviour of prolactin receptors from human ovarian tissue.

Receptors for 125I-labelled human prolactin have been identified in the crude membrane fraction isolated from human ovarian tissue. The non-ionic detergent Triton X-100, has been used to solubilize the membrane fraction. The presence of the receptor in the detergent extract was demonstrated by gel filtration and sucrose density gradient centrifugation. The binding was time-temperature dependent, being maximal at 23 degrees C after 15 h of incubation. Large amounts of other peptide hormones did not inhibit the binding of 125I-labelled human prolactin. The binding Scatchard analysis demonstrated that the affinity of the soluble receptor (Ka 1.13 +/- 0.15 X 10(10) M-1) for the labelled hormone was slightly greater than that of the crude membrane fraction (Ka 0.91 +/- 0.12 X 10(10) M-1). The binding capacity of the solubilized receptor was also significantly greater than that seen in the particulate before solubilization. The apparent Stokes radius of the solubilized receptor was estimated to be 57 A and that the hormone-receptor complex 60 A. The sedimentation coefficient of the solubilized receptor was 7.0 +/- 0.1 s, whereas that of the hormone-receptor complex was 7.5 +/- 0.2 s.

Absolute quantitation of specific mRNAs in cell and tissue samples by comparative PCR.

A comparative PCR assay, for the absolute quantitation of specific mRNAs in cell and tissue samples, has been designed to overcome problems with previous techniques. cDNAs made from the RNAs are co-amplified with "competitor" plasmid templates under conditions in which reagents are not limiting at the equivalence point, thereby preventing competition between target and competitor templates and distinguishing the assay from competitive PCR assays. The cDNAs are serially diluted, and competitor templates concentrations are kept constant, rather than vice versa, as occurs in competitive PCR assays. Products from target and competitor templates are resolved by electrophoresis and measured by phosphorescent or fluorescent imagery. Both products are measured to minimize errors in the competitor:target ratio. A synthetic external standard RNA is included in the tissue lysis solution and co-purified with endogenous mRNAs, thereby being subjected to identical losses of yield during subsequent procedures. The determination of the number of copies of external standard cDNA allows inefficiencies of RNA extraction and cDNA synthesis to be taken into account. Standard concentrations of plasmids containing the endogenous target sequences are also measured, so that corrections can be made for discrepancies due to unequal amplification of target and competitor sequences. These corrections, together with the use of an external standard and the PCR conditions chosen, allow for the accurate, specific and sensitive determination of the absolute number of mRNA copies in a sample.

Thymidylate synthase gene promoter polymorphisms are associated with TSmRNA expressions but not with microsatellite instability in colorectal cancer.

BACKGROUND: Microsatellite instability (MSI) is a biological characteristic of most tumours, being involved in 85% of hereditary non-polyposis colorectal cancer (HNPCC). It also occurs in 10-15% of sporadic colorectal cancers (CRC). HNPCC appears to be caused by germline mutations in mismatch repair (MMR) genes, which are responsible for repairing single base-pair mismatches. MSI is also associated with a better response of CRC to adjuvant chemotherapy with fluoropyrimidines. We investigated any relationship between the MSI status and the TSmRNA expression, the polymorphisms of 5-Fluorouracil (5-FU cellular target, the enzyme thymidylate synthase (TS) and TS expression evaluated by means of immunohistochemistry. MATERIALS AND METHODS: A series of 80 colorectal cancers was evaluated for MSI and polymorphisms in the 3'UTR and the 5'UTR of the TS gene by a PCR assay. TSmRNA was quantified by real-time PCR and the TS expression by immunohistochemical assay. RESULTS: There was no significant association between the polymorphisms in the TS gene and the MSI or between the TSmRNA expression and the MSI status. CRC with a 3R/3R or 2R/3R genotype showed a significantly higher TSmRNA expression than those with the 2R/2R genotype (p = 0.001 and p = 0.028, respectively). Another significant association was found between the TSmRNA expression and the TS immunohistochemical determination (p = < 0.05). No association was found between the polymorphism of the 3'UTR and the TSmRNA expression. CONCLUSION: Our data show that there is no association between MSI status and the polymorphisms in the 3' and 5' UTRs and the TS expression. Tumour samples displaying the 3R/3R or 2R/3R genotype of TS have higher TSmRNA levels than the 2R/2R genotype. Polymorphic variant of the 3'UTR does not influence the TSmRNA level. We found a relationship between the TSmRNA expression, evaluated by real-time PCR, and with the TS level determined by immunohistochemical assay. Thus, genotyping of the 5'UTR and quantification of the TSmRNA expression in human CRC could be considered as predictors for response to SFU-based chemotherapy. The evaluation of the TS expression by means of immunohistochemistry assay remains a safe and reliable assay in CRC.

Structure and dynamics of water confined in silica hydrogels: X-ray scattering and dielectric spectroscopy studies.

We have used a sol-gel technique to obtain optically transparent hydrogels in which water is confined within a 3D silica matrix. In this work we report X-ray scattering and dielectric spectroscopy measurements on samples having different aging times and compare them with previously obtained results with near-infrared (NIR) absorption spectroscopy. X-ray scattering at room temperature enables to characterize the structure and size of the matrix pores and the non-uniform distribution of water inside the hydrogel. Broad band dielectric spectroscopy in the temperature range 130-280 K enables to study water dynamics. In aged hydrogels two relaxations are clearly evident and show characteristic temperature dependence. The faster relaxation has an Arrhenius behavior in the whole temperature range investigated with an activation enthalpy of approximately 50 kJ/mol; it is attributed to water molecules strongly interacting with the silica matrix. The slower relaxation has a markedly non-Arrhenius behavior which can be fitted with a Vogel-Fulcher-Tamman (VFT) relation with critical temperature of approximately 100 K and activation enthalpies of 35 and 95 kJ/mol at 300 and 170 K respectively; it is attributed to water molecules within the pores that do not interact strongly with the matrix and behave collectively. The VFT temperature dependence of the dielectric relaxation time suggests that this water does not crystallize, in agreement with previous results from NIR spectroscopy.

Biological aggressiveness evaluation in prostate carcinomas:immunohistochemical analysis of PCNA and p53 in a series of Gleason 6 (3+3) adenocarcinomas.

We selected 63 prostate tumors with Gleason's grade 6 (3+3), commonly showing both tubular and cribrous patterns. We compared in both patterns the expression of two of the most used biologic markers: PCNA and p53, with the aim to verify the validity of the Gleason's grading system to compare the morphologic grade with biologic aggressiveness and prognostic value. We did not find any statistical difference in the protein immunopositivity, indicating that both patterns could have identical biologic behaviour; then we confirmed the validity of Gleason's system for considering both tubular and cribrous patterns as an intermediate grade of tumoral differentiation. Moreover, we found a linear relationship between the increase of PCNA and the accumulation of mutated p53; this datum could confirm the hypothesis that p53 mutation is a late event in prostate carcinogenesis.

[Lipid metabolism in newborn infants at birth. Obstetrical-pediatric aspects]. / Alcune osservazioni sul metabolismo lipidico del neonato alla nascita. Aspetti ostetrico-pediatrici.

Lipid parameters in the cord blood of neonates and that of their mothers at birth were studied in a series of 67 subjects divides in accordance with prior disease or diseases arising during pregnancy. From the results obtained in this albeit restricted study, agreement is expressed with the literature view that there is a common genetic control of lipid metabolism in the foetus, which is unusual and independent of that in the mother. An interesting, though unexplained finding was the absence of prebetalipoproteins in the cord blood of 71.5% of the control group.

[Sex steroids and function of the liver]. / Steroidi sessuali e funzione epatica

PIP: The effects of the sex steroids (androgens, estrogens, and protesterone) on liver function, and the metabolism of these substances and their regulation by the liver, are reviewed. The physiology of the hepatocyte is discussed in relation to the enzyme systems active in various aspects of steroid metabolism, the reductases and dehydrogenases, the hydrolases, and the isomerases. Because of the central regulatory and metabolic importance of the liver, primary genito-endocrine disorders may also have hepatic repercussions. Conversely, correlations between liver disease and menstrual disorders have been found by many authors. Reports of clinical symtomatology and laboratory findings are related to the metabolic processes of the liver and the sex hormones.^ieng

[Androgenic evaluation of women with late-onset or persistent acne]. / Valutazione androgenica in donne con acne ad insorgenza tardiva o persistente.

The authors have studied the androgenic patterns in 29 women with late-onset persistent acne vulgaris. Clinical evaluation of acne, menstrual history and serum determinations of SHBG, total-T, free-T, DHEAS, delta 4A have been carried out. A mild and heterogeneous hyperandrogenism was found in 70% of women, thus, a greater steroid bioavailability for peripheral conversion and/or a direct stimulation of the pilosebaceous unit can be postulated. Androgenic evaluation in women with late-onset or persistent acne vulgaris is useful, mainly for hormonal management.

Which kind of vascular access for hemodialysis in pediatric patients?

The choice of vascular access in hemodialysis pediatric patients can be challenging, due to the small diameter of vessels. In the last 19 years, 38 arteriovenous fistulas (AVF) for hemodialysis have been created on 21 patients; 25 of them were radio-cephalic AVF. The evaluation of the vessels was, in the majority of cases, done by clinical criteria. A local anesthesia was used in all surgical procedures. The percentage of early AVF failure was 24%. Long-term AVF survival was 97%, 65% and 55% at respectively 1, 3 and 5 years. Our data indicate that even in pediatric patients the radio-cephalic fistula is the first choice surgical procedure.