Genome-wide analysis of cyclins in maize (Zea mays)

Cyclins are primary regulators of the activity of cyclin-dependent kinases and play crucial roles in cell cycle progression in eukaryotes. Although extensive studies have revealed the roles of some cyclins and underlying mechanisms in plants, relatively few cyclins have been functionally analyzed in maize. We identified 59 cyclins in the maize genome, distributed on 10 chromosomes; these were grouped into six types by phylogenetic analysis. The cyclin genes in the maize genome went through numerous tandem gene duplications on five chromosomes. However, no segmental duplications, which occur in rice, were found on maize chromosomes. This information allows us to assess the position of plant cyclin genes in terms of evolution and classification, which will be useful for functional studies of maize cyclins.

Antitumour response of a double mutant of staphylococcal enterotoxin C2 with the decreased affinity for MHC class II molecule

Staphylococcal enterotoxin C2 (SEC2) is one of the most potent known activators of human T lymphocytes, and recombinant SEC2 shows promising clinical values, but SEC2 can cause food poisoning and toxic shock syndrome in vivo. In this study, site-directed mutagenesis has been used to introduce alanine substitutions at Phe144 and Leu45 in the molecule. The mutant genes were cloned and expressed, and the corresponding proteins were purified by nickel agarose affinity chromatography. We found that the SEC2 mutant proteins could stimulate the proliferation of human peripheral blood lymphocytes and inhibit the growth of tumour cells as native SEC2. Furthermore, flow cytometry assay showed that mSEC2(F44A, L45A) drastically reduced the ability of the toxin to bind to MHC class II. Physiological parameters revealed that mSEC2(F44A, L45A) reduced significantly rat temperature compared with native SEC2 in vivo. Our results clearly suggest that this genetically modified SEC2 protein is less toxic and justifies its further development as a new, safer antitumour superantigen to prevent SEC2 intoxication.

Effects of adenoviral-mediated coexpression of bone morphogenetic protein-7 and insulin-like growth factor-1 on human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Bone morphogenetic protein-7 (BMP-7) and insulin-like growth factor-1 (IGF-1) are important in periodontal reconstruction. However, their synergistic effect in periodontal regeneration by gene delivery has not been reported. In this study, gene delivery of these two growth factors to human periodontal ligament cells (hPDLCs) was examined for its effects on cell proliferation and differentiation.

MATERIAL AND METHODS

Recombinant adenoviruses containing both human BMP-7 and IGF-1 cDNA created by introducing the internal ribosome entry site (IRES) sequence were used to transfer the genes into hPDLCs. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle analysis were used to observe their effects on cell proliferation, while alkaline phosphatase activity measurement, RT-PCR and in vivo tests were conducted to investigate their effects on cell differentiation.

RESULTS

The proliferation of hPDLCs transduced by adenoviruses coexpressing BMP-7 and IGF-1 was suppressed while their differentiation ability was enhanced. There was a synergism of BMP-7 and IGF-1 in up-regulating alkaline phosphatase activity and mRNA levels of collagen type I and Runx2. Implantation in vivo with scaffolds illustrated that the transduced cells exhibited osteogenic differentiation and formed bone-like structures.

CONCLUSION

The combined delivery of BMP-7 and IGF-1 genes using an IRES-based strategy synergistically enhanced differentiation of hPDLCs. It is suggested that this could be a new potential method in gene therapy for periodontal reconstruction.

AKT1 polymorphisms are associated with tuberculosis in the Chinese population

AKT1, a serine/threonine kinase, plays a critical role in the controlling of intracellular growth of Mycobacterium tuberculosis. In this study, we investigated whether polymorphisms in AKT1 affect susceptibility to tuberculosis (TB). Two single nucleotide polymorphisms of AKT1, IVS3+18C>T and +726G>A were genotyped in Chinese patients with pulmonary TB by polymerase chain reaction-restriction fragment length polymorphism. Patients with pulmonary TB had significantly lower IVS3+18 C/C genotype and higher C/T genotype compared with age-, gender- and ethnically matched controls (P < 0.05). The T-A haplotype frequency was significantly higher in patients than in controls (P < 0.05). In conclusion, our result indicates that AKT1 polymorphisms are associated with susceptibility to pulmonary TB.

Rapid domain wall motion in permalloy nanowires excited by a spin-polarized current applied perpendicular to the nanowire

We study domain wall dynamics in Permalloy nanowires excited by alternating spin-polarized current applied perpendicular to the nanowire. Spin torque ferromagnetic resonance measurements reveal that domain wall oscillations at a pinning site in the nanowire can be excited with velocities as high as 800 m/s at current densities below 10{7} A/cm{2}.

Overexpression of type-A rice response regulators, OsRR3 and OsRR5, results in lower sensitivity to cytokinins

Response regulators are part of a two-component regulatory system. The type-A Arabidopsis response regulators act as negative regulators. To understand the function of type-A response regulators in the model monocot plant, rice (Japonica cultivar-group: Zhonghua11), we overexpressed two type-A OsRR genes, OsRR3 and OsRR5 (pACT1:OsRR3 and pACT1:OsRR5). We hoped to gain insight into their molecular function in cytokinin-signaling pathways. Both OsRR3 and OsRR5 overexpressors had longer roots and more lateral roots compared with Zhonghua11, when treated with exogenous cytokinin. Using callus formation and chlorophyll content assays, we found that Zhonghua11 was more sensitive to cytokinin compared with other cultivars of rice, expressing high transcript levels of OsRR3 and OsRR5. The expression of most type-A OsRR genes was repressed by OsRR3 and OsRR5 overexpression. However, semi-quantitative RT-PCR showed that three type-A OsRR genes showed increased expression. Our results suggest that both OsRR3 and OsRR5 mainly act as negative regulators of cytokinin signaling, as indicated by the reduced sensitivity of OsRR3 and OsRR5 overexpressors to exogenous cytokinins.

What is the benefit of bevacizumab combined with chemotherapy in patients with recurrent ovarian, fallopian tube or primary peritoneal malignancies?

The aim of this retrospective analysis was to investigate the efficacy and adverse effects of the monoclonal antivascular endothelial growth factor antibody bevacizumab (Avastin(R)) combined with chemotherapeutic agents in non-protocol patients with recurrent ovarian, fallopian tube, or primary peritoneal malignancies. Using our databases, we identified patients treated with bevacizumab combination therapy since June 2005. Responses were evaluated with Response evaluation Criteria in Solid tumors and serum CA125 Rustin criteria. Toxicity was assessed according to the Common toxicity Criteria (CTC) v.3.0. Data from 64 patients were included. The median patient age was 58 years, and they had undergone a median of 4.5 (range, 1-10) prior cytotoxic chemotherapy regimens. The median length of follow-up was 8 months (range, 2-29). The most commonly used combinations were bevacizumab plus taxanes (26.6%) and plus cyclophosphamide (26.6%). A median of 4 cycles of therapy with a median bevacizumab dose of 3,600 mg (range, 500-18,240) were administered. An overall response rate of 21.3% was observed in 13 patients with partial response, and another 42.6% of patients had stable disease. Among the patients with elevated pretreatment serum CA125 concentration, an overall response rate of 46.3% (25/54) was observed according to modification of the Rustin criteria. Fifteen (23.4%) patients had grades 3 or 4 adverse events. Gastrointestinal perforations occurred in 2 (3.1%) patients. Seventeen (26.6%) patients had improved performance status scores. Bevacizumab combined with chemotherapy showed promising clinical benefits, with significant response of serum CA125 concentration and moderate adverse effects.

A novel allele, HLA-A*110203, was identified in a Chinese individual

This allele is characterized by a nucleotide substitution (C>T) in exon 4 at position nt 672, codon 200 (ACC>ACT), no coding change.

A frame shift due to a two-nucleotide deletion results in an HLA-B null allele, B*9549N

This report describes the identification of a new human leukocyte antigen (HLA) class I null allele, B*9549N, resulting from a premature stop codon in exon 3.

A novel HLA-B*37 allele, B*370105, was identified in a Chinese Han individual

We report here the sequence of a novel human leukocyte antigen B*37 allele, B*370105, which is identical to B*370101 except for a single nucleotide substitution in exon 3 at nucleotide 558 where C>A, codon 162 GGC>GGA, no coding change.

Resonant nonlinear damping of quantized spin waves in ferromagnetic nanowires: a spin torque ferromagnetic resonance study

We use spin torque ferromagnetic resonance to measure the spectral properties of dipole-exchange spin waves in Permalloy nanowires. Our measurements reveal that geometric confinement has a profound effect on the damping of spin waves in the nanowire geometry. The damping parameter of the lowest-energy quantized spin-wave mode depends on applied magnetic field in a resonant way and exhibits a maximum at a field that increases with decreasing nanowire width. This enhancement of damping originates from a nonlinear resonant three-magnon confluence process allowed at a particular bias field value determined by quantization of the spin-wave spectrum in the nanowire geometry.

Origin of the inverse spin switch effect in superconducting spin valves

Known as the spin switch effect (SSE), the resistance of a ferromagnet/superconductor/ferromagnet (F/S/F) spin valve near its superconducting transition temperature T c is different for parallel (R P) and antiparallel (R AP) configurations of the F layers. Here, we report the observation of the coexistence of the standard (RP>RAP) and inverse (RP<RAP) SSE in Ni81Fe19/Nb/Ni81Fe19/Ir25Mn75 spin valves. Our measurements reveal that the inverse SSE arises from a dissipative flow of vortices induced by stray magnetic fields from Néel domain-wall pairs in the F layers.

The role of secondary cytoreductive surgery for recurrent mucinous epithelial ovarian cancer (mEOC)

BACKGROUND

Mucinous epithelial ovarian cancer (mEOC) may exhibit a distinct biological behavior in epithelial ovarian cancer (EOC). The role of secondary cytoreductive surgery was evaluated in patients with recurrent mEOC, and the prognosis was assessed.

METHODS

Twenty-one patients with stages IIc to IV mEOC who experienced disease recurrence and received secondary cytoreductive surgery at Fudan University Cancer Hospital between Jan. 1997 and Dec. 2005 were retrospectively reviewed. Survival curves were generated using the Kaplan-Meier method and the significant comparison of survival rate was estimated by the log-rank test.

RESULTS

The median progression-free interval (PFI) was 14 months (range, 5-46 months) after the first cytoreduction. Seven patients (33%) who received secondary cytoreductive surgery were optimally cytoreduced with residual disease less than or equal 1cm, and the other 14 patients (67%) underwent suboptimal surgical cytoreduction. The overall median survival time was 27 months (range, 8-64 months). The median survival time after recurrence was 10 months (range, 3-32 months). There was no significant statistical difference in median survival between patients with optimal and suboptimal secondary surgical cytoreduction, with an estimated survival of 10 months and 9.8 months, respectively (P>0.05).

CONCLUSION

Optimal primary cytoreductive surgery for advanced mEOC was very important. Once it recurs, the prognosis is very poor. Patients with recurrent mEOC should be carefully assessed before performing secondary cytoreductive surgery, as this may have limited impact on the overall survival rates.