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181.
Cellular and molecular control of dendritic growth and development of cerebellar Purkinje cells 总被引:5,自引:0,他引:5
Kapfhammer JP 《Progress in histochemistry and cytochemistry》2004,39(3):131-182
Purkinje cells are the principal neurons of the cerebellar cortex and are characterized by a large and highly branched dendritic tree. For this reason, they have for a long time been an attractive model system to study the regulation of dendritic growth and differentiation. In this article, I will first review studies on different aspects of Purkinje cell dendritic development and then go on to present studies which have aimed at experimentally altering Purkinje cell dendritic development. Some of the cellular and molecular mechanisms which have been shown by these studies to be important determinants of Purkinje cell dendritic development will be discussed, in particular the role of the parallel fiber input, of hormones, and of neuronal growth factors. The organotypic slice culture method will be introduced as an important experimental tool to study Purkinje cell dendritic development under controlled conditions. Using cerebellar slice cultures, protein kinase C (PKC) has been identified as a major determinant of Purkinje cell dendritic development and the contribution of specific isoforms of PKC will be discussed. Finally, it will be shown that Purkinje cell dendritic development in slice cultures does not depend on the activation of glutamate receptors and appears to be independent of the presence of the neurotrophin BDNF. These studies indicate that the initial outgrowth of the Purkinje cell dendritic tree can occur in the absence of signals derived from afferent fibers, but is under control of PKC signaling. 相似文献
182.
Xiao L Ryan UM Graczyk TK Limor J Li L Kombert M Junge R Sulaiman IM Zhou L Arrowood MJ Koudela B Modrý D Lal AA 《Applied and environmental microbiology》2004,70(2):891-899
The genetic diversity of Cryptosporidium in reptiles was analyzed by PCR-restriction fragment length polymorphism and sequence analysis of the small subunit rRNA gene. A total of 123 samples were analyzed, of which 48 snake samples, 24 lizard samples, and 3 tortoise samples were positive for Cryptosporidium: Nine different types of Cryptosporidium were found, including Cryptosporidium serpentis, Cryptosporidium desert monitor genotype, Cryptosporidium muris, Cryptosporidium parvum bovine and mouse genotypes, one C. serpentis-like parasite in a lizard, two new Cryptosporidium spp. in snakes, and one new Cryptosporidium sp. in tortoises. C. serpentis and the desert monitor genotype were the most common parasites and were found in both snakes and lizards, whereas the C. muris and C. parvum parasites detected were probably the result of ingestion of infected rodents. Sequence and biologic characterizations indicated that the desert monitor genotype was Cryptosporidium saurophilum. Two host-adapted C. serpentis genotypes were found in snakes and lizards. 相似文献
183.
Free-living nitrogen-fixing prokaryotes (diazotrophs) are ubiquitous in soil and are phylogenetically and physiologically highly diverse. Molecular methods based on universal PCR detection of the nifH marker gene have been successfully applied to describe diazotroph populations in the environment. However, the use of highly degenerate primers and low-stringency amplification conditions render these methods prone to amplification bias, while less degenerate primer sets will not amplify all nifH genes. We have developed a fixed-primer-site approach with six PCR protocols using less degenerate to nondegenerate primer sets that all amplify the same nifH fragment as a previously published PCR protocol for universal amplification. These protocols target different groups of diazotrophs and allowed for direct comparison of the PCR products by use of restriction fragment length polymorphism fingerprinting. The new protocols were optimized on DNA from 14 reference strains and were subsequently tested with bulk DNA extracts from six soils. These analyses revealed that the new PCR primer sets amplified nifH sequences that were not detected by the universal primer set. Furthermore, they were better suited to distinguish between diazotroph populations in the different soils. Because the novel primer sets were not specific for monophyletic groups of diazotrophs, they do not serve as an identification tool; however, they proved powerful as fingerprinting tools for subsets of soil diazotroph communities. 相似文献
184.
Scholz D Baumann K Grassberger M Wolff-Winiski B Rihs G Walter H Meingassner JG 《Bioorganic & medicinal chemistry letters》2004,14(11):2983-2986
The 17-alpha-substituted triterpene 1 [(17alpha)-23-(E)-dammara-20,23-diene-3beta,25-diol] showed promising activity in animal models of immunosuppression and inflammation. Using a mouse model for inflammatory skin diseases (oxazolone-induced allergic contact dermatitis, ACD) as the directing in vivo test system, Structure-activity-relationship studies with the aim to understand the necessary structural requirements for the biological activity of 1 were conducted. Furthermore, we anticipated to identify biologically active compounds with the 17beta configuration, which are thermodynamically more stable and much easier to synthesize. This was achieved by identifying the 17-beta substituted dammarane 5B and its analogues. 相似文献
185.
Manley PW Breitenstein W Brüggen J Cowan-Jacob SW Furet P Mestan J Meyer T 《Bioorganic & medicinal chemistry letters》2004,14(23):5793-5797
The constitutively active Abl kinase activity of the Bcr-Abl oncoprotein is causative for chronic myelogenous leukemia. Urea derivatives, structurally related to the therapeutic agent STI571, have been identified, which potently inhibit the tyrosine kinase activity of recombinant Abl. In particular a dimethylamino-aniline derivative (18) inhibited c-Abl transphosphorylation with an IC(50) value of 56 nM. Although this activity was not translated into cellular activity against the constitutively activated oncogenic Bcr-Abl, a number of compounds from this series potently inhibited cellular PDGFR autophosphorylation. It was also possible to differentiate between c-Abl and PDGFR kinase inhibition, with compound 22 being selective towards Abl and 23 selective for PDGFR. 相似文献
186.
Zadrazil J Jabry SA Bachleda P Gibejová A 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2004,148(2):171-173
This paper presents our experience to date with using a cyclosporine formulation Equoral (IVAX Pharmaceuticals) together with mycophenolate mofetil plus a steroid immunosuppressive regimen in the treatment of de novo renal transplant recipients. Ten cadaveric donor renal transplant recipients of mean age 51.6 years (range 37-66) were followed up over 6 months for the development of rejection attacks and side effects. All patients received prednisolone, mycophenolate mofetil (1 g/day during the first 5 days posttransplant and then 20 mg/kg/day) plus cyclosporine (3 mg/kg/day). Biopsy proven acute rejection episodes were observed in 2 out of 10 patients (20%). Six months patient as well as renal graft survival rate was 100%. The development of graft function was immediate after transplantation. The mean serum creatinine levels were gradually decreased. Over the 6-month posttransplant period, the function of the graft was satisfactory and stable. The majority of observed adverse events were those commonly reported with the use of cyclosporine and they resolved with a reduction in cyclosporine dose. Equoral treatment demonstrated an acceptable safety profile with maintenance of adequate renal function without incidence of malignancy/lymphoproliferative disease or serious infections. In conclusion, Equoral plus mycophenolate mofetil immunosuppression seems effective and safe on terms acute rejection rates, patient and renal graft survival rates and side profiles. 相似文献
187.
Rejtarová O Slízová D Smoranc P Rejtar P Bukac J 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2004,148(2):241-243
Mineralization and ossification in the human costal cartilages were studied radiologically. The aim of our study was to evaluate differences between males and females with respect to patterns of costal cartilage calcification and also with respect to ageing. Material for this study consists of 1044 chest and abdominal radiograms of the Czech population from the Department of Radiology (537 males and 507 females). Further radiograms of 18 chest plates were obtained at routine necropsy of cadavers. The radiograms were examined for pattern of ossification of the costal cartilage. The first rib cartilages were not considered because there are no sex differences. The lower ribs exhibit sexual dimorphism. Mineralization and ossification changes appear at the end of puberty and their occurrence increases with age. The sexual difference in pattern of human costal cartilages is statistically significant and thus highly predictive of sex determination. 相似文献
188.
Petrek J 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2004,148(2):157-160
The present findings show the existence of significant differences in latency and amplitude of some waves of ERPs to three subclasses of nouns or verbs. Latency LP3 of ERPs to action verbs was shorter than latency of the same wave to abstract verbs. In nouns the relation was a similar (manipulable objects versus abstract ones). The amplitude of early positive components (P1, P2) and BN3 wave also depended on semantic attributes of nouns and verbs. Some waves of ERPs to motion verbs in our experiment had significantly higher amplitude than the same waves of ERPs to nonmanipulable objects. Also revealed was interaction between some ERP features and the subject's gender. It was primarily the amplitude of BP2, the size of which depended on gender in all cases--BP2 amplitude was significantly higher in females then in males. In the other components (BP1, BP4, BN2 and BN4) there were fewer significant differences and if they do occurred, then their amplitude was higher in males than in females. In some cases, gender also affected latency of waves LP2, LN1 and LN4 of ERPs to the same noun or verb subclass--latencies of these waves were shorter in females. 相似文献
189.
Petrek J 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2004,148(2):145-152
Event-related potentials (ERPs) to word stimuli were registered in 20 twenty-one-year-old students (7 males and 13 females) of the Faculty of Medicine of Palacky University. In an ideal case in the first 800 ms after the onset of stimulus ERP consists of three clear positive and four negative waves. The amplitude of some waves of ERPs shows a high degree of inter-individual variability. It was also revealed that the latency and amplitude of some ERPs waves to word stimuli depends on the gender and on the site of the registration electrode on the scalp of the subject. Latencies of components LP2 and LN4 in all electrodes are shorter in females than in males, component LN2 behaves reversely--its latency is shorter in males. On the other hand, the amplitude of dependent variables BP2, BN2 and PV1 is in most electrodes higher in females than in males--except for the amplitude of components BP4 and BN1. 相似文献
190.
The c-Jun N-terminal kinase (JNK/SAPK) signaling cascade controls a spectrum of cellular processes, including cell growth, differentiation, transformation, and apoptosis. We recently demonstrated that stress kinase MKK7, a direct activator of JNKs, couples stress signaling to G2/M cell cycle progression, CDC2 expression, and cellular senescence. We further explored other molecules involved in JNK pathway and found that both MKK4, another direct activator of JNK, and c-Jun, a direct substrate of JNK, have similar roles to MKK7. Here we discuss the importance of the MKK4/MKK7-JNK-c-Jun pathway linking stress and developmental signals to cell proliferation, cell cycle progression, cellular senescence, and apoptosis including recent unpublished data from our lab. 相似文献