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Sleeve fractures are generally restricted to children or adolescents, and usually occur at the lower patella pole. Here we report on a superior pole sleeve fracture in an adult that occurred following forceful passive physiotherapy after cast immobilization. To our knowledge, this is the first report of a superior pole sleeve fracture in an otherwise healthy adult. The case highlighted that a diagnosis of a superior patella pole sleeve fracture in an adult can easily be missed because it is a rare injury, and hence is unlikely to be suspected by physicians. [ABSTRACT FROM AUTHOR]

An embryonic stem cell is a powerful tool for investigation of early development in vitro. The study of embryonic stem cell mediated neuronal differentiation allows for improved understanding of the mechanisms involved in embryonic neuronal development. We investigated expression profile changes using time course cDNA microarray to identify clues for the signaling network of neuronal differentiation. For the short time course microarray data, pattern analysis based on the quadratic regression method is an effective approach for identification and classification of a variety of expressed genes that have biological relevance. We studied the expression patterns, at each of 5 stages, after neuronal induction at the mRNA level of embryonic stem cells using the quadratic regression method for pattern analysis. As a result, a total of 316 genes (3.1%) including 166 (1.7%) informative genes in 8 possible expression patterns were identified by pattern analysis. Among the selected genes associated with neurological system, all three genes showing linearly increasing pattern over time, and one gene showing decreasing pattern over time, were verified by RT-PCR. Therefore, an increase in gene expression over time, in a linear pattern, may be associated with embryonic development. The genes: Tcfap2c, Ttr, Wnt3a, Btg2 and Foxk1 detected by pattern analysis, and verified by RT-PCR simultaneously, may be candidate markers associated with the development of the nervous system. Our study shows that pattern analysis, using the quadratic regression method, is very useful for investigation of time course cDNA microarray data. The pattern analysis used in this study has biological significance for the study of embryonic stem cells. [ABSTRACT FROM AUTHOR]

Methamphetamine, a commonly used addictive drug, is a powerful addictive stimulant that dramatically affects the CNS. Repeated METH administration leads to a rewarding effect in a state of addiction that includes sensitization, dependence, and other phenomena. It is well known that susceptibility to the development of addiction is influenced by sources of reinforcement, variable neuroadaptive mechanisms, and neurochemical changes that together lead to altered homeostasis of the brain reward system. These behavioral abnormalities reflect neuroadaptive changes in signal transduction function and cellular gene expression produced by repeated drug exposure. To provide a better understanding of addiction and the mechanism of the rewarding effect, it is important to identify related genes. In the present study, we performed gene expression profiling using microarray analysis in a reward effect animal model. We also investigated gene expression in four important regions of the brain, the nucleus accumbens, striatum, hippocampus, and cingulated cortex, and analyzed the data by two clustering methods. Genes related to signaling pathways including G-protein-coupled receptor-related pathways predominated among the identified genes. The genes identified in our study may contribute to the development of a gene modeling network for methamphetamine addiction. [ABSTRACT FROM AUTHOR]

The gene encoding Thermus caldophilus GK24 (Tca) DNA polymerase was cloned into Escherichia coli using the structural gene coding for Thermus aquaticus YT-l (Taq) DNA polymerase as a hybridization probe. The nucleotide sequence of the cloned DNA was determined. The primary structure of the Tca DNA polymerase was deduced from the nucleotide sequence. The Tca DNA polymerase comprised 834 amino acid residues and its molecular mass was determined to be 93,810. On alignment of the whole amino acid sequence, Tca DNA polymerase showed a high sequence homology with the E. coli DNA polymerase I-like DNA polymerases, and 86% identity with Taq DNA polymerase, 38% with E. coli and Streptococcus pneumoniae (Spn) DNA polymerase I. An extremely high sequence identity was observed in the region containing the polymerase activity. The codon usage in the Tca DNA polymerase gene was in fact similar to the characteristic usages in the genes for proteins from bacteria of genus Thermus: the G+ C content in the third position of the codons was as high as 93 %. The Tca DNA polymerase gene was expressed under the control of tac promoter on a high copy plasmid, pTCA in E. coli. [ABSTRACT FROM AUTHOR]

The article describes the case of a 24-year-old soldier who was admitted in an orthopedic institute for the swelling, bruising as well as pain in his right foot and ankle. Based on the examination conducted by medical professionals on the patient, they found that he is suffering from calcaneo-fibular ligament (CFL) tenderness. Several months after his treatment, they found that he had bony lesion and expanded sclerotic area.

LY6K is a cancer biomarker and a therapeutic target that induces invasion and metastasis. However, the molecular mechanisms that determine human LY6K transcription are completely unknown. To elucidate the mechanisms involved in human LY6K gene regulation and expression, multiple cis-elements were predicted usingTRANSFACsoftware, and the LY6K regulatory region was identified using the luciferase assay in the human LY6K gene promoter. We performed ChIP, EMSA, and supershift assays to investigate the transcription factor activity on the LY6K promoter, and the effect of a SNP and CpG site methylation on AP-1 transcription factor binding affinity. AP-1 and the CREB transcription factor bound to LY6K promoter within -550/-1, which was essential for LY6K expression, but only the AP-1 heterodimer, JunD, and Fra-1, modulates LY6K gene transcriptional level. A decrease in LY6K was associated with the SNP242 C allele, a polymorphic G/C-SNP at the 242 nucleotide in the LY6K promoter region (rs2585175), or methylation of the CpG site, which was closely located with the AP-1 site by interfering with binding of the AP-1 transcription factor to the LY6K promoter. Our findings reveal an important role for AP-1 activation in promoting LY6K gene expression that regulates cell mobility of breast cancer cells, whereas the SNP242 C allele or methylation of the CpG site may reduce the risk of invasion or metastasis by interfering AP-1 activation. [ABSTRACT FROM AUTHOR]

The SeqA protein, which prevents overinitiation of chromosome replication, has been suggested to also participate in the segregation of chromosomes in Escherichia coli. Using a bacterial two-hybrid system, we found that SeqA interacts with the Parc subunit of topoisomerase IV (topo IV), a type II topoisomerase involved in decatenation of daughter chromosomes and relief of topological constraints generated by replication and transcription. We demonstrated that purified SeqA protein stimulates the activities of topo IV, both in relaxing supercoiled plasmid DNA and converting catenanes to monomers. The same moderate levels of SeqA protein did not affect the activities of DNA gyrase or topoisomerase I. At higher levels of SeqA, topo IV favored the formation of catenanes, caused by intermolecular strand exchange among plasmid DNA aggregates formed by SeqA. Excess SeqA inhibited the activity of all topoisomerases. We also found that stimulation of topo IV was dependent upon the affinity of SeqA for DNA. Our results suggest that this stimulation is mediated by the specific interaction of topo IV with SeqA. Some of the known phenotypes of mutant cells lacking SeqA, such as deficient chromosome segregation and increased negative superhelicity, support that the SeqA protein is required for topo IV-mediated relaxation and decatenation of chromosomes and plasmids, during and after their replication. [ABSTRACT FROM AUTHOR]

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disorder. Although a myriad of research groups have attempted to identify a new therapeutic target for AD PKD, no drug has worked well in clinical trials. Our research group has focused on the receptor for advanced glycation end products (RAGE) gene as a novel target for ADPKD. This gene is involved in inflammation and cell proliferation. We have already confirmed that blocking RAGE function attenuates cyst growth in vitro. Based on this previous investigation, our group examined the effect of RAGE on cyst enlargement in vivo. PC2R mice, a severe ADPKD mouse model that we generated, were utilized. An adenovirus containing anti-RAGE shRNA was injected intravenously into this model. We observed that RAGE gene knockdown resulted in loss of kidney weight and volume. Additionally, the cystic area that originated from different nephron segments decreased in size because of down-regulation of the RAGE gene. Blood urea nitrogen and creatinine values tended to be lower after inhibiting RAGE. Based on these results, we confirmed that the RAGE gene could be an effective target for ADPKD treatment. [ABSTRACT FROM AUTHOR]

Mutations in the SO42-/Cl- /OH- exchanger Slc26a2 cause the disease diastrophic dysplasia (DTD), resulting in aberrant bone development and, therefore, skeletal deformities. DTD is commonly attributed to a lack of chondrocyte SO42- uptake and proteoglycan sulfation. However, the skeletal phenotype of patients with DTD is typified by reduction in cartilage and osteoporosis of the long bones. Chondrocytes of patients with DTD are irregular in size and have a reduced capacity for proliferation and terminal differentiation. This raises the possibility of additional roles for Slc26a2 in chondrocyte function. Here, we examined the roles of Slc26a2 in chondrocyte biology using two distinct systems: mouse progenitor mesenchymal cells differentiated to chondrocytes and freshly isolated mouse articular chondrocytes differentiated into hypertrophic chondrocytes. Slc26a2 expression was manipulated acutely by delivery of Slc26a2 or shSlc26a2 with lentiviral vectors. We demonstrate that slc26a2 is essential for chondrocyte proliferation and differentiation and for proteoglycan synthesis. Slc26a2 also regulates the terminal stage of chondrocyte cell size expansion. These findings reveal multiple roles for Slc26a2 in chondrocyte biology and emphasize the importance of Slc26a2-mediated protein sulfation in cell signaling, which may account for the complex phenotype of DTD. [ABSTRACT FROM AUTHOR]

Cilia in ciliated cells consist of protruding structures that sense mechanical and chemical signals from the extracellular environment. Cilia are assembled with variety molecules via a process known as intraflagellar transport (IFT). What controls the length of cilia in ciliated cells is critical to understand ciliary disease such as autosomal dominant polycystic kidney disease, which involves abnormally short cilia. But this control mechanism is not well understood. Previously, multiple tubular cysts have been observed in the kidneys of max-interacting protein 1 (Mxi1)-deficient mice aged 6 months or more. Here, we clarified the relationship between Mxi1 inactivation and cilia disassembly. Cilia phenotypes were observed in kidneys of Mxi1-deficient mice using scanning electron microscopy to elucidate the effect of Mxi1 on renal cilia phenotype, and cilia disassembly was observed in Mxi1-deficient kidney. In addition, genes related to cilia were validated in vitro and in vivo using quantitative PCR, and Ift20 was selected as a candidate gene in this study. The length of cilium decreased, and p-ERK level induced by a cilia defect increased in kidneys of Mxi1-deficient mice. Ciliogenesis of Mxi1-deficient mouse embryonic fibroblasts (MEFs) decreased, and this abnormality was restored by Mxi1 transfection in Mxi1-deficient MEFs.We confirmed that ciliogenesis and Ift20 expression were regulated by Mxi1 in vitro. Wealso determined that Mxi1 regulates Ift20 promoter activity via Ets-1 binding to the Ift20 promoter. These results indicate that inactivating Mxi1 induces ciliary defects in polycystic kidney. [ABSTRACT FROM AUTHOR]

The pathogenic mechanisms of human autosomal dominant polycystic kidney disease (ADPKD) have been well known to include the mutational inactivation of PKD2. Although haploinsufficiency and loss of heterozygosity at the Pkd2 locus can cause cyst formation in mice, polycystin-2 is frequently expressed in the renal cyst of human ADPKD, raising the possibility that deregulated activation of PKD2 may be associated with the cystogenesis of human ADPKD. To deter- mine whether increased PKD2 expression is physiologically pathogenic, we generated PKD2-overexpressing transgenic mice. These mice developed typical renal cysts and an increase of proliferation and apoptosis, which are reflective of the human ADPKD phenotype. These manifestations were first observed at six months, and progressed with age. In addition, we found that ERK activation was induced by PKD2 overexpression via B-Raf signaling, providing a possible molecular mechanism of cystogenesis. In PKD2 transgenic mice, B-Raf/MEK/ERK sequential signaling was up-regulated. Additionally, the transgenic human polycystin-2 partially rescues the lethality of Pkd2 knock-out mice and therefore demonstrates that the transgene generated a functional product. Functional strengthening or deregulated activation of PKD2 may be a direct cause of ADPKD. The present study provides evidence for an in vivo role of overexpressed PKD2 in cyst formation. This transgenic mouse model should pro- vide new insights into the pathogenic mechanism of human ADPKD. [ABSTRACT FROM AUTHOR]

Human peroxiredoxins 1 and 2, also known as Prx1 and Prx2, are more than 90% homologous in their amino acid sequences. Prx1 and Prx2 are elevated in various cancers and are shown to influence diverse cellular processes. Although their growth regulatory role has traditionally been attributed to the peroxidase activity, the physiological significance of this function is unclear because the proteins are highly susceptible to inactivation by H2O2. A chaperone activity appears to emerge when their peroxidase activity is lost. Structural studies suggest that they may form a homodimer or doughnut-shaped homodecamer. However, little information is available whether human Prx1 and Prx2 are duplicative in structure and function. We noted that Prx1 contains a cysteine (Cys83) at the putative dimer-dimer interface, which is absent in Prx2. We studied the role of Cys83 in regulating the peroxidase and chaperone activities of Prx1, because the redox status of Cys83 might influence the oligomeric structure and consequently the functions of Prx1. We show that Prx1 is more efficient as a molecular chaperone, whereas Prx2 is better suited as a peroxidase enzyme. Substituting Cys83 with Ser83 (Prx1C83S) results in dramatic changes in the structural and functional characteristics of Prx1 in a direction similar to those of Prx2. Here we also report the first crystal structure of human Prx1 and the presence of the Cys83-Cys83 bond at the dimer-dimer interface of decameric Prx1. These findings are consistent with the hypothesis that human Prx1 and Prx2 possess unique functions and regulatory mechanisms and that Cys83 bestows a distinctive identity to Prx1. [ABSTRACT FROM AUTHOR]

Cdt1, a protein essential in G1 for licensing of origins for DNA replication, is inhibited in S-phase, both by binding to geminin and degradation by proteasomes. Cdt1 is also degraded after DNA damage to stop licensing of new origins until after DNA repair. Phosphorylation of Cdt1 by cyclin-dependent kinases promotes its binding to SCF-Skp2 E3 ubiquitin ligase, but the Cdk2/Skp2-mediated pathway is not essential for the degradation of Cdt1. Here we show that the N terminus of Cdt1 contains a second degradation signal that is active after DNA damage and in S-phase and is dependent on the interaction of Cdt1 with proliferating cell nuclear antigen (PCNA) through a PCNA binding motif. The degradation involves N-terminal ubiquitination and requires Cul4 and Ddb1 proteins, components of an E3 ubiquitin ligase implicated in protein degradation after DNA damage. Therefore PCNA, the matchmaker for many proteins involved in DNA and chromatin metabolism, also serves to promote the targeted degradation of associated proteins in S-phase or after DNA damage. [ABSTRACT FROM AUTHOR]