High resolution flat crystal spectrometer for the Shanghai EBIT

We report on a high resolution flat crystal spectrometer designed for the Shanghai EBIT. Its energy range is from 0.5 to 10 keV. Three crystals can be installed in the vacuum chamber simultaneously, and its effective Bragg angle can be covered from 15 degrees to 75 degrees . A vacuum version charge-coupled device detector is used for detection of photons. An energy resolution under 1 eV was reached in measurements of the 4.5 keV Kalpha(1) line by using an x-ray generator with a titanium anode. The spectrometer was also tested to operate well on the Shanghai EBIT by observing the lines of tungsten at around 3.2 keV.

A novel frameshift mutation of the EDA1 gene in a Chinese Han family with X-linked hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a rare skin disease characterized by hypotrichosis, hypodontia and hypohidrosis. HED can be autosomal dominant, autosomal recessive or X-linked. However, X-linked HED (XLHED; OMIM 305100) is the most common form. Mutations within the EDA1 gene, which encodes ectodysplasin-A, are responsible for XLHED. In this study, we investigated the EDA1 gene in a Chinese Han family with XLHED, and found a novel 1-bp deletion mutation (c.952delG) in exon 9 of the EDA1 gene, which results in a frameshift and premature termination codon. This result suggests that the c.952delG mutation of the EDA1 gene is likely to be the disease-causing mutation for XLHED in this family. Our study adds new data to the worldwide knowledge of the molecular basis of XLHED.

X-Ray structures and binding properties of molecular clips based on diethoxycarbonyl glycoluril

The crystal structures of two molecular clips derived from diethoxycarbonyl glycoluril were reported. Their unique binding behavior towards hydroquinone, which is different from Nolte's clips (high affinity for resorcinol), has been characterized through 1H NMR and IR. Job-plot analyses provide good evidence of a 1:1 stoichiometry for the complexes.Key words: crystal structure, molecular clips, binding properties

A novel missense mutation L468Q of keratin 6a in pachyonychia congenita type 1

BACKGROUND

Pachyonychia congenita is an autosomal dominant disorder that usually develops in early infancy. The major features of the syndrome are hypertrophic nail dystrophy, palmoplantar keratoderma and oral leucokeratosis, accompanied by other ectodermal defects, according to subtype.

OBJECTIVE

To analyse the K6a gene mutation in a sporadic Chinese patient with pachyonychia congenita type 1 (PC-1) and to explore the relationship between the genotype and phenotype of PC-1.

METHODS

Genomic DNA was extracted from peripheral blood of the patient with PC-1 and 100 unrelated controls. The whole coding region of K6a gene was amplified using long-range polymerase chain reaction (PCR); nested PCR was then used to amplify the mutation 'hot-spot' of the K6a gene. The PCR products were directly sequenced to detect the mutation.

RESULTS

A novel missense mutation L468Q in the helix 2B domain of the K6a polypeptide was identified in the patient but not in the healthy individuals from the family and 100 unrelated control individuals.

CONCLUSIONS

We describe this mutation for the first time, and provide further evidence that the helix boundary motif sequences of K6a are a mutation 'hot-spot'.

The familial risk of acne vulgaris in Chinese Hans ? a case-control study

BACKGROUND

Acne is a chronic inflammatory disease of the pilosebaceous follicles. Recent studies bring us increasing evidences that hereditary factors play an important but indirect role in acne.

OBJECTIVE

To investigate the possible role of genetic factors in the pathogenesis of acne vulgaris in Chinese Han ethnic group.

PATIENTS AND METHODS

Volunteers of 975 acne cases and 580 controls were included, contributing 3009 and 1825 first-degree relatives, respectively. One thousand and eighty-five first-degree relatives of acne cases were affected with facial acne. This compared with 223 first-degree relatives of non-acne controls. The odds ratio was used to estimate the relative risk for acne vulgaris associated with having an affected first-degree relative.

RESULTS

The risk of acne vulgaris occurring in a relative of a patient with acne vulgaris was significantly greater than for the relative of an unaffected individual (odds ratio 4.05, 95% confidence interval (CI): 3.45-4.76, P<0.001).

CONCLUSION

Our study suggests that familial factors are important in determining individual susceptibility to acne vulgaris.

Effects of seed migration on post-implant dosimetry of prostate brachytherapy

Brachytherapy using permanent seed implants has been an effective treatment for prostate cancer. However, seeds will migrate after implant, thus making the evaluation of post-implant dosimetry difficult. In this study, we developed a computer program to simulate seed migration and analyzed dosimetric changes due to seed migration at various migration amounts. The study was based on 14 patients treated with Pd-103 at the James Cancer Hospital. Modeling of seed migration, including direction, distance as well as day of migration, was based on clinical observations. Changes of commonly used dosimetric parameters as a function of migration amount (2, 4, 6 mm respectively), prostate size (from 20 to 90 cc), and prostate region (central vs peripheral) were studied. Change of biological outcome (tumor control probability) due to migration was also estimated. Migration reduced prostate D90 to 99+/-2% of original value in 2 mm migration, and the reduction increased to 94+/-6% in 6 mm migration. The reduction of prostate dose led to a 14% (40%) drop in the tumor control probability for 2 mm (6 mm) migration, assuming radiosensitive tumors. However, migration has less effect on a prostate implanted with a larger number of seeds. Prostate V100 was less sensitive to migration than D90 since its mean value was still 99% of original value even in 6 mm migration. Migration also showed a different effect in the peripheral region vs the central region of the prostate, where the peripheral mean dose tended to drop more significantly. Therefore, extra activity implanted in the peripheral region during pre-plan can be considered. The detrimental effects of migration were more severe in terms of increasing the dose to normal structures, as rectum V50 may be 70% higher and urethra V100 may be 50% higher in the case of 6 mm migration. Quantitative knowledge of these effects is helpful in treatment planning and post-implant evaluation.

Fibroblast growth factor-10 prevents H2O2-induced cell cycle arrest by regulation of G1 cyclins and cyclin dependent kinases

We studied the effects of fibroblast growth factor (FGF-10) on H2O2-induced alveolar epithelial cell (AEC) G1 arrest and the role of G1 cyclins. FGF-10 prevented H2O2-induced AEC G1 arrest. FGF-10 induced 2-4-fold increase in cyclin E, cyclin A and CDKs (2,4) alone and in AEC treated with H2O2. H2O2 downregulated cyclin D1; FGF-10 blocked these effects. FGF-10 prevented H2O2-induced upregulation of CDK inhibitor, p21. SiRNAp21 blocked H2O2-induced downregulation of cyclins, CDKs and AEC G1 arrest. Accordingly, we provide first evidence that FGF-10 regulates G1 cyclins and CDKs, and prevents H2O2-induced AEC G1 arrest.

Effect of Akt inhibition on scatter factor-regulated gene expression in DU-145 human prostate cancer cells

The cytokine scatter factor (SF) (hepatocyte growth factor) transduces various biologic actions, including cell motility, invasion, angiogenesis and apoptosis inhibition. The latter is relevant to understanding the role of SF in promoting tumor cell survival in different contexts, for example, detachment from basement membrane, growth in metastatic sites and responses to chemo- and radiotherapy. Previously, we showed that SF protects cells against apoptosis owing to DNA damage, by a mechanism involving phosphoinositol-3-kinase/c-Akt signaling. Here, we used DNA microarray assays to identify c-Akt-regulated genes that might contribute to cell protection. DU-145 human prostate cancer cells were transfected+/-a dominant-negative mutant Akt, treated+/-SF and analysed for gene expression using Affymetrix arrays. These studies identified SF-regulated genes for which induction was c-Akt-dependent vs -independent. Selected microarray findings were confirmed by semiquantitative and quantitative reverse transcription-polymerase chain reaction. We tested the contribution of four SF-inducible/c-Akt-dependent genes (AMPD3, EPHB2, MX1 and WNT4) to protection against adriamycin (a DNA topoisomerase IIalpha inhibitor) using RNA interference. Knockdown of each gene except EPHB2 caused a small but significant reduction in the SF cell protection. The lack of effect of EPHB2 knockdown may be due to the fact that DU-145 cells contain a single-mutant EPHB2 allele. A combination of three small interfering RNAs blocked most of the protection by SF in both DU-145 and T47D cells. These findings identify novel c-Akt-regulated genes, some of which contribute to SF-mediated cytoprotection.

MHC haplotypic association in Chinese Han patients with vitiligo

BACKGROUND

Serological typing of the human leucocyte antigen (HLA) has shown discrepancies in HLA associations with vitiligo in different ethnic populations.

OBJECTIVE

To evaluate the distributions of HLA at class I and II loci that may contribute to the genetic susceptibility of vitiligo patients in Chinese Hans population.

METHODS

We analysed the allelic frequencies of HLA class I and II by using the polymerase chain reaction sequence-specific primer (PCR-SSP) method in 187 patients with vitiligo and 273 controls in Chinese Hans. The linkage disequilibrium was calculated from a 2 x 2 table.

RESULTS

Two-locus haplotypes including HLA-A25-B13, HLA-A25-B27, HLA-A25-Cw*0602, HLA-A25-DQA1*0302, HLA-A25-DQA1*0601, HLA-A25-DQB1*0303, HLA-B13-Cw*0602, HLA-B13-DQA1*0302, HLA-B13-DQA1*0601, HLA-B27-Cw*0602, HLA-B27-DQA1*0302, HLA-B27-DQA1*0601, HLA-B27-DQB1*0303, HLA-B27-DQB1*0503, HLA-Cw*0602-DQA1*0302, HLA-Cw*0602-DQA1*0601, HLA-Cw*0602-DQB1*0303, HLA-Cw*0602-DQB1*0503 and HLA-DQA1*0302-DQB1*0503 were associated with all types of vitiligo in Chinese Hans. The extended haplotypes HLA-A25-B13-Cw*0602, HLA-A25-B27-Cw*0602, HLA-DQA1*0302-DQB1*0303-Cw*0602 and HLA-B13-DQB1*0303-Cw*0602 were found to be associated with all types of vitiligo in Chinese Hans, whereas the frequency of HLA-A25-Cw*0602-DQA1*0302 was significantly increased in generalized vitiligo but not in localized vitiligo. The frequencies of HLA-A25-DQA1*0302-DQB1*0503 and HLA-A30-DQA1*0302-DQB1*0303 were higher in childhood vitiligo than in adult vitiligo, and the frequency of HLA-A25-B13-DQB1*0303-Cw*0602 was shown to be associated with adult vitiligo but not childhood vitiligo.

CONCLUSION

This study demonstrates not only the differential association between HLA markers and types of vitiligo according to distribution or age at onset but also newly found high-risk haplotypes in Chinese vitiligo patients.

RAD001 (everolimus) down-regulates cyclin D3 and c-Myc and is particularly effective in the treatment of aggressive B-cell lymphomas

17573

Background: Aggressive B-cell lymphoma is recently found to be associated with constitutive activation of the PI3K/Akt pathway, and thereby is relatively resistant to apoptosis. Furthermore, activation of the PI3K/Akt signaling pathway can result in the upregulation of cyclin D3 and c-Myc through inhibition of the cap-independent RNA translation. Since mTOR is closely associated with the regulation of the translation process, and is a downstream mediator of the PI3K/Akt signalling pathway, this study aimed to examine if RAD001, an inhibitor of mTOR, can be effective in the treatment of aggressive B-cell lymphoma. Methods: Pfeiffer (diffuse large cell lymphoma), Ramos (EBV (−) Burkitt’s lymphoma), Raji (EBV (+) Burkitt’s lymphoma), and MC116 (EBV (−) undifferentiated lymphoma) cell lines were used in this study. Expression of pAkt, p70S6 kinase, pp70 S6 kinase, 4E-BP1, p4E-BP1, cyclin D3, and c-Myc was measured by immunoblotting. Results: Akt was constitutively activated in all four lymphoma cell lines. Downstream effectors of PI3/Akt signaling pathway, including p70S6 kinase and 4E-BP1, were also phosphorylated in these lymphoma cell lines. RAD001 downregulated p70S6 kinase and 4E-BP1, and the IC50s of growth suppression ranged from 5 to 50 nM, without significant difference between EBV (+) and EBV (−) cell lines. The IC50s of these lymphoma cell lines appeared to be much lower than those obtained from the carcinoma cell lines, suggesting that lymphomas may be particularly sensitive to growth inhibition by RAD001. RAD001 blocked cell cycle progression in G0/G1 phase in all four lymphoma cell lines while there was no significant increase in sub-G1 phases, suggesting that apoptosis was not the major mechanism of RAD001-induced growth inhibition. In addition, in parallel with the RAD001-induced growth inhibition, a dose-dependent down-regulation of the expression of cyclin D3 and c-Myc was demonstrated. Conclusions: The mechanism of action is at least partly due to downregulation of cyclin D3 and c-Myc, and subsequent G0/G1 block. Since overexpression of cyclin D3 and c-Myc is also closely associated with chemoresistance of aggressive B-cell lymphoma, RAD001 may be a useful adjunct in the treatment of this group of tumors.

No significant financial relationships to disclose.