Collateral circulation of the rat lower limb and its significance in ischemia-reperfusion studies.

PURPOSE: Rats are the most commonly used animal model for studies of acute lower limb ischemia-reperfusion. The ischemia induced by arterial clamping may cause milder damage than the application of a tourniquet if the presence of a possible collateral system is considered. METHODS: Male Wistar rats were randomized into three groups: in group A, the muscle weight affected by ischemia was measured; in group B, the severity of muscle damage caused by the application of a tourniquet and by infrarenal aortic occlusion was examined. Blood and muscle samples were taken from group B to assess the serum necroenzyme, potassium and TNF-α levels, as well as the muscle fiber viability and for histological examinations. In group C, the identification of the lower limb collateral system was performed using corrosion casting. RESULTS: Tourniquet application affected the lower muscle mass and resulted in significantly more severe injury compared to infrarenal aortic occlusion. This difference was reflected in the serum necroenzyme, potassium and TNF-α levels. The histological examination and viability assay confirmed these findings. The corrosion casts showed several anastomoses capable of supplying the lower limb. CONCLUSION: Tourniquet application proved to be capable of inducing absolute lower limb ischemia, in contrast to infrarenal aortic ligation, where a rich collateral system is considered to help mitigate the injury.

A new operative technique for aural haematoma in dogs: A retrospective clinical study.

Aural haematoma is treated either by surgical or by conservative treatment. Both techniques usually require several interventions and re-checks. A new operation technique has been evaluated that requires only a single procedure but is as effective as the techniques used previously. The haematoma is opened, cleaned surgically and the two layers of the auricular cartilage are appositioned inside with several suture lines placed on both sides of the incision, alternating the sides approaching to the sagittal cavity. None of the suture lines is stitched through the auricle completely as they all run intradermally on the side of the haematoma and to the cartilage on the other side. Twenty-three dogs with aural haematoma were treated between 2006 and 2012. In 21 (91%) of them, the haematoma healed without any auricle deformity. No secondary intervention was necessary in any of the cases. None of the 23 animals experienced a relapse during follow-up. The new method offers a minor risk of postoperative complications while accomplishing high healing rates.

[The possible options for the prevention of preeclampsia]. / A praeeclampsia megelozésének lehetoségei.

This review summarizes the possible options for the prevention of preeclampsia based on important factors of patomechanism. The effects of antioxidants have been described in numerous clinical researches based on the oxidative hypothesis. Another important factor is the change of nitric oxide activity. Nitric oxide donors are able to compensate the symptoms of preeclampsia. The inverse relationship between the calcium intake and gestational hypertension has been known for a long time. The calcium supplementation seems to be a good opportunity to prevent preeclampsia. With low molecular weight heparins we can intervene in the patomechanisms of preeclampsia by antithrombocyte effects, vasoactive properties and impact on throphoblast cell morphology and differentiation. Thrombocyte aggregation inhibitors were examined in number of studies because they reduced thromboxane mediated vasoconstriction and inhibited placental thrombosis. Several studies verify whether prophylaxis with low molecular weight heparins and low dose aspirin could improve pregnancy outcome in preeclampsia.

[Hemorrheological changes and their clinical relevance in pre-eclampsia]. / Haemorrheologiai változások és azok klinikai jelentosége praeeclampsiában.

This review summarizes the hemorheological changes during gestation and their clinical relevance in pre-eclampsia. The gestational disease named pre-eclampsia, characterized by proteinuria (more than 0.3 g/day) and hypertension (blood pressure above 140/90 mmHg), exists from the 20th gestational week until the sixth postpartum week. Its etiology is complex; the pathomechanism mainly involves disturbances in cross talks among the vegetative system, the placenta and the circulatory system. Soluble factors of placenta mediate circulatory changes, which result in adaptive responses in both vegetative and circulatory systems. Derailment of this adaption, however, leads to increased turbulence and local damages in cellular elements of the circulatory system. The initial local lesion progresses to a generalized form. Later, these events will continue to strengthen their own cycle. As a result, an unstable circulatory state will be established, which causes organ damages.

Elimination of Dirofilaria (syn. Nochtiella) repens microfilariae in dogs with monthly treatments of moxidectin 2.5%/imidacloprid 10% (Advocate, Bayer) spot-on.

Elimination of microfilaria in dogs infected with zoonotic Dirofilaria repens would be desirable to reduce further spread. Moxidectin has demonstrated efficacy against microfilariae and safety in dogs infected with Dirofilaria immitis and could be an option for controlling D. repens microfilariae. A field study with 64 dogs previously confirmed positive for D. repens microfilaria was conducted in Hungary, in which a spot-on product (Advocate, Bayer) was tested. Treatments were applied to 44 dogs once a month for 3 months (five dogs) or 6 months (22 dogs), alternatively every 2 weeks for 6 months (17 dogs). Twenty dogs remained untreated. Microfilaria counts were performed once a month and for a further 6 months following the last treatment. Two weeks after the first treatment, 38 of 44 dogs were microfilaria negative. Four weeks after the initial treatment, one dog still showed a low microfilaria count. Following the second treatment, all treated dogs were negative. This status was maintained during the 6-month observation period after the last treatment. These data demonstrate the successful long-lasting elimination of microfilariae. Moreover, it may be supposed that adult D. repens were killed based on the observation that no further microfilariae were seen up to 6 months after the end of the treatment period.

Promoter analysis suggests the implication of NFkappaB/C-Rel transcription factors in biliary atresia.

BACKGROUND/AIMS: Microarray studies used to describe altered gene expression patterns in tissues are a promising new way to provide insight into the pathomechanism of biliary atresia (BA). The hypothesis in this study was that altered gene expression in BA may be linked to regulatory transcription factors (TF). The overrepresentation of transcription factor binding sites (TFBS) in the promoter regions of genes with altered expression would support this hypothesis. METHODOLOGY: Using previously published data, the prevalence of TFBSs in the promoter regions of genes with altered expression in BA was analyzed and compared with the overall prevalence in known promoter sequences. RESULTS: In the pooled BA gene list 195 different TFBS were identified. The prevalence of TFBSs of the members of NFkappaB/c-Rel family was higher compared with the background model. CONCLUSIONS: NFkappaB/c-Rel play a role in the development and function of the immune system. Thus, the results of this study support current theories and experiments which link the immune system to perinatal BA. The information obtained in this analysis will help to understand the pathogenesis of BA, but further experimental and human data are required to validate the significance of these TFs in disease pathogenesis.

Identification of consensus genes and key regulatory elements in 5-fluorouracil resistance in gastric and colon cancer.

BACKGROUND: 5-fluorouracil (5-FU) is widely used in the treatment of gastric and colorectal cancer. Recent microrarray studies associated different gene lists with 5-FU resistance. A major challenge in the genomic era is to find the most validated genes, and to decipher the regulatory networks responsible for the expression changes in a set of co-regulated transcripts. Our aim was to find genes repeatedly associated with 5-FU resistance, and to identify transcription factors (TFs) having overrepresented binding sites (TFBSs) in the promoter regions of genes associated with 5-FU resistance. MATERIALS AND METHODS: The analyzed data originated from 5 different publications describing genome-wide gene expression patterns associated with 5- FU resistance in gastric and colorectal cancer. First, a data warehouse containing all genes associated with resistance was set up. 39 genes were identified which were repeatedly associated with resistance. Of these, using the EZ-Retrieve web service, proximal promoter sequences were available for 33 genes. The MotifScanner software was used to detect TFBSs in this set of sequences. RESULTS: A total of 200 different TFBSs were identified. Using the statistics tool of the Java program TOUCAN, 4 binding sites were found to be significantly overrepresented: NFKappaB50 (p = 0.01), EGR2 (p = 0.027), EGR3 (p = 0.007), and NGFIC (or EGR4) (p = 0.001). These genes intercept apoptotic pathways at multiple locations in the tumor cells. CONCLUSION: We identified a consensus gene list associated with 5-FU resistance, performed an in silico comparative promoter analysis, and highlighted the potential implication of some TFs in the development of chemoresistance.

Highly expressed genes are associated with inverse antisense transcription in mouse.

There is a growing evidence, that antisense transcription might have a key role in a range of human diseases. Although predefined sense-antisense pairs were extensively studied, the antisense expression of the known sense genes is rarely investigated. We retrieved and correlated the expression of sense and antisense sequences of 1182 mouse transcripts to assess the prevalence and to find the characteristic pattern of antisense transcription. We contrasted three Affymetrix MGU74A version 1 mouse genome chips to six MGU74A version 2 chips. For these 1182 transcripts, the version 1 chips contain the antisense sequences of the transcripts presented on the version 2 chips. The original data was taken from the GEO database (GDS431 and GDS432). As the Affymetrix data are semiquantitative, the relative expression levels of antisense partners were analysed. We detected antisense transcription, although the average antisense expression is shifted towards smaller expression values (MGU74A version 1, 516; version 2, 1688). An inverse direct correlation between sense and antisense expression values could be observed at high expression values. At a very high relative expression--above 40,000--the Pearson correlation coefficient is getting closer to -1. Transcripts with high inverse expression ratio may be correlated to the investigated gene (major histocompatibility complex class II trans activator). The ratio of sense to antisense transcripts varied among different chromosomes; on chromosomes 14 and 1 the level of antisense expression was higher than that of sense. We conclude that antisense transcription is a common phenomenon in the mouse genome. The hypothesis of regulatory role of antisense transcripts is supported by the inverse antisense gene expression of highly expressed genes.

Comparative promoter analysis of doxorubicin resistance-associated genes suggests E47 as a key regulatory element.

Working under the assumption that up- or downregulation of genes implicated in chemoresistance may be the result of altered function of regulatory transcription factors (TF), over-represented TF-binding sites of gene lists previously associated with doxorubicin resistance were the target of our search. First, a data warehouse was set up containing 52 genes which were present in at least two gene lists; of those, proximal promoter sequences (1 kb upstream and 0.05 kb downstream of the transcriptional start sites) could be retrieved from genomic databases for 45 genes using the EZ-Retrieve. The TOUCAN tool MotifScanner, which searches the TRANSFAC database, was used to detect TF-binding sites (TFBSs) in our set of sequences. The statistics tool of the Java program TOUCAN was applied to the data with the appropriate expected frequencies file to compare the measured prevalence to a background model. The most significantly over-represented TFBS was that of E47 (p=0.00024, prevalence: 0.2 vs. background: 8.19E-6). In summary, based on the results of our analysis it is hypothesized that the E47 transcription factor may contribute to doxorubicin resistance.

Computational analysis reveals 43% antisense transcription in 1182 transcripts in mouse muscle.

It is increasingly evident that there is a widespread antisense transcription in the human and other eukaryotic genomes. However, the concept of general antisense expression is rarely investigated. We retrieved and correlated the expression of sense and antisense sequences of 1182 mouse transcripts to assess the prevalence of antisense transcription. We contrasted 20 Affymetrix MGU74A version 1 mouse genome chips to 12 MGU74A version 2 chips. For these 1182 transcripts, the version 1 chips contained the antisense sequences of the transcripts presented on the version 2 chips. The original data was taken from the GEO database. As the Affymetrix data is semi quantitative, the relative levels of antisense partners were analysed. We detected antisense transcription with an overall magnitude of 43% relative to sense transcription in the investigated transcripts. The average MGU74A version 1 expression is shifted towards smaller expression values (MGU74A version 1: 525.1; version 2: 1219.1; t-test: p < 0.001). A direct correlation between sense and antisense expression values could not be observed. Genes with high inverse expression values may be correlated to the investigated condition: genes where sense/control and control/antisense ratios were above two may be included in the pathogenetic pathways associated with dystrophin deficiency. The ratio of sense to antisense transcription varied between different chromosomes. We conclude that antisense transcription is a common phenomenon in the mouse genome and may have indirect regulatory functions.

[Microelectrodes and their application in diagnostic medicine]. / Mikroelektródok az orvosi diagnosztikában.

Microelectrodes are in common use in medical detection systems. The binding of two complementary nucleic acid sequences is called hybridization. Today the major obstacle of large-scale hybridization approaches is the large time-dependency of a single reaction, which is up to 16 hours. As the DNA molecules can be electronically charged, the binding could be facilitated and confirmed using an electronic control system. The authors' team aimed to develop a microelectrode system capable for the detection and control of hybridization. A microelectrode head is immersed in small liquid drop. Here, the platinum counterelectrode is surrounded by a non-conducting quartz capillary. The reference electrode is chloridized silver immersed in saturated Ag/Cl dilution. The Ag/AgCl/1 M KCl +AgCl microelectrode in stabilized against the calomel electrode in the first hours, and remains stable between 7th and 30th hours. This can be verified by the minimal drop in the potential difference. Thus the AgCl saturated KCl electrode is usable for several days for actual measurements. The detector is controlled by an attached computer. The system can be used to detect hybridization in a micro-cell located on a gold-plate. The electrode can be dismounted and reused after repeated chloridization of the Ag wire. The microelectrode is simple, cheap; thus is best suited for application in future automated diagnostic detection systems.

[The problem of multiple testing and solutions for genome-wide studies]. / A "multiple testing" problémája és a genomiális kísérletekre alkalmazott megoldások.

The problem of multiple testing and its solutions for genome-wide studies. Even if there is no real change, the traditional p = 0.05 can cause 5% of the investigated tests being reported significant. Multiple testing corrections have been developed to solve this problem. Here the authors describe the one-step (Bonferroni), multi-step (step-down and step-up) and graphical methods. However, sometimes a correction for multiple testing creates more problems, than it solves: the universal null hypothesis is of little interest, the exact number of investigations to be adjusted for can not determined and the probability of type II error increases. For these reasons the authors suggest not to perform multiple testing corrections routinely. The calculation of the false discovery rate is a new method for genome-wide studies. Here the p value is substituted by the q value, which also shows the level of significance. The q value belonging to a measurement is the proportion of false positive measurements when we accept it as significant. The authors propose using the q value instead of the p value in genome-wide studies.

[Hybridization and their application in the DNA array technology]. / A hibridizáció es alkalmazása DNS-array rendszerekben.

Hybridization and their application in the DNA array technology. DNA hybridization arrays measure simultaneously the expression of several genes. First, a known DNA sequence (probe) is fixed on a firm basis. Then the complementer sequence (target sequence) is linked to it during the hybridization process. The target sequence extracted from biological samples is fluorescently, enzimatically or radioactively labeled before detection. Higher expression results in higher signal in the detection system. Unlabeled DNA strands can also be detected, as the electronic and optical characteristics of the DNA is altered after complementer hybridization. In this review we summarize the basics of hybridisation and its newest application area in the DNA array systems.

Reanalysis of genotype distributions published in "Neurology" between 1999 and 2002.

The authors tested 123 genotypes described in 54 papers published in the journal Neurology between 1999 and 2002 to ascertain whether these genotype distributions deviated from Hardy-Weinberg equilibrium (HWE). Unreported deviations from HWE in 19 genotype distributions described in 11 of the papers were discovered. The authors also report additional information that could have been extracted after calculating HWE and conclude that HWE values should be mandatory in population genetic studies published in Neurology.