Cytokinin‐dependent specification of the functional megaspore in the Arabidopsis female gametophyte

The life cycle of higher plants alternates between the diploid sporophytic and the haploid gametophytic phases. In angiosperms, male and female gametophytes develop within the sporophyte. During female gametophyte (FG) development, a single archesporial cell enlarges and differentiates into a megaspore mother cell, which then undergoes meiosis to give rise to four megaspores. In most species of higher plants, including Arabidopsis thaliana, the megaspore closest to the chalaza develops into the functional megaspore (FM), and the remaining three megaspores degenerate. Here, we examined the role of cytokinin signaling in FG development. We characterized the FG phenotype in three triple mutants harboring non‐overlapping T–DNA insertions in cytokinin AHK receptors. We demonstrate that even the strongest mutant is not a complete null for the cytokinin receptors. Only the strongest mutant displayed a near fully penetrant disruption of FG development, and the weakest triple ahk mutant had only a modest FG phenotype. This suggests that cytokinin signaling is essential for FG development, but that only a low threshold of signaling activity is required for this function. Furthermore, we demonstrate that there is elevated cytokinin signaling localized in the chalaza of the ovule, which is enhanced by the asymmetric localization of cytokinin biosynthetic machinery and receptors. We show that an FM‐specific marker is absent in the multiple ahk ovules, suggesting that disruption of cytokinin signaling elements in Arabidopsis blocks the FM specification. Together, this study reveals a chalazal‐localized sporophytic cytokinin signal that plays an important role in FM specification in FG development.     

Inhibitory effect on NO production of triterpenes from the fruiting bodies of Ganoderma lucidum

Four new lanostane triterpenes, butyl lucidenate P (1), butyl lucidenate D₂ (2), butyl lucidenate E₂ (3) and butyl lucidenate Q (4) along with 11 known compounds (5–15) were isolated from the fruiting bodies of Ganoderma lucidum. Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. Their anti-inflammatory activity was evaluated against LPS-induced NO production in macrophage RAW 264.7 cells. Compounds 1, 3, 4, 9, 10 and 15 showed inhibitory potency with IC₅₀ values of 7.4, 6.4, 4.3, 9.4, 9.2 and 4.5 μM, respectively. Compounds 1, 3 and 15 dose-dependently reduced the LPS-induced iNOS expressions. Preincubation of cell with 1, 3 and 15 significantly suppressed LPS-induced expression of COX-2 protein.     

Synthesis and SAR of potent and selective tetrahydropyrazinoisoquinolinone 5-HT2C receptor agonists

The 5-HT_2C receptor has been implicated as a critical regulator of appetite. Small molecule activation of the 5-HT_2C receptor has been shown to affect food intake and regulate body weight gain in rodent models and more recently in human clinical trials. Therefore, 5-HT_2C is a well validated target for anti-obesity therapy. The synthesis and structure–activity relationships of a series of novel tetrahydropyrazinoisoquinolinone 5-HT_2C receptor agonists are presented. Several members of this series were identified as potent 5-HT_2C receptor agonists with high functional selectivity against the 5-HT_2A and 5-HT_2B receptors and reduced food intake in an acute rat feeding model upon oral dosing.     

Electron microscopy: essentials for viral structure, morphogenesis and rapid diagnosis

Electron microscopy(EM) should be used in the front line for detection of agents in emergencies and bioterrorism,on accounts of its speed and accuracy.However,the number of EM diagnostic laboratories has decreased considerably and an increasing number of people encounter difficulties with EM results.Therefore,the research on viral structure and morphology has become important in EM diagnostic practice.EM has several technological advantages,and should be a fundamental tool in clinical diagnosis of viruses,particularly when agents are unknown or unsuspected.In this article,we review the historical contribution of EM to virology,and its use in virus differentiation,localization of specific virus antigens,virus-cell interaction,and viral morphogenesis.It is essential that EM investigations are based on clinical and comprehensive pathogenesis data from light or confocal microscopy.Furthermore,avoidance of artifacts or false results is necessary to exploit fully the advantages while minimizing its limitations.     

Brain structure and spatial sensitivity profile assessing by near‐infrared spectroscopy modeling based on 3D MRI data

The goal of this study is to prove that the light propagation in the head by used the 3‐D optical model from in vivo MRI data set can also provide significant characteristics on the spatial sensitivity of cerebral cortex folding geometry based on Monte Carlo simulation. Thus, we proposed a MRI based approach for 3‐D brain modeling of near‐infrared spectroscopy (NIRS). In the results, the spatial sensitivity profile of the cerebral cortex folding geometry and the arrangement of source‐detector separation have being necessarily considered for applications of functional NIRS. The optimal choice of source‐detector separation is suggested within 3–3.5 cm by the received intensity with different source‐detector separations and the ratio of received light from the gray and white matter layer is greater than 50%. Additionally, this study has demonstrated the capability of NIRS in not only assessing the functional but also detecting the structural change of the brain by taking advantage of the low scattering and absorption coefficients observed in CSF of sagittal view. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Population-Based 5-Year Follow-Up Study in Taiwan of Dementia and Risk of Stroke

Background

This study estimates the risk of stroke within 5 years of newly diagnosed dementia among elderly persons aged 65 and above. We examined the relationship between antipsychotic usage and development of stroke in patients with dementia.

Methods

We conducted a nationwide 5-year population-based study using data retrieved from the Longitudinal Health Insurance Database 2005 (LHID2005) in Taiwan. The study cohort comprised 2243 patients with dementia aged ≥65 years who had at least one inpatient service claim or at least 2 ambulatory care claims, whereas the comparison cohort consisted of 6714 randomly selected subjects (3 for every dementia patient) and were matched with the study group according to sex, age, and index year. We further classified dementia patients into 2 groups based on their history of antipsychotic usage. A total of 1450 patients were classified into the antipsychotic usage group and the remaining 793 patients were classified into the non-antipsychotic usage group. Cox proportional-hazards regressions were performed to compute the 5-year stroke-free survival rates after adjusting for potentially confounding factors.

Results

The dementia patients have a 2-fold greater risk of developing stroke within 5 years of diagnosis compared to non-dementia age- and sex-matched subjects, after adjusting for other risk factors (95% confidence interval (CI) = 2.58–3.08; P<.001). Antipsychotic usage among patients with dementia increases risk of stroke 1.17-fold compared to patients without antipsychotic treatment (95% CI = 1.01–1.40; P<.05).

Conclusions

Dementia may be an independent risk factor for stroke, and the use of antipsychotics may further increase the risk of stroke in dementia patients.     

The Influence of Hepatitis B Viral Load and Pre-S Deletion Mutations on Post-Operative Recurrence of Hepatocellular Carcinoma and the Tertiary Preventive Effects by Anti-Viral Therapy

Background

Whether or not hepatitis B virus (HBV) genotypes, mutations, and viral loads determine outcomes for patients with HBV-induced hepatocellular carcinoma (HCC) remains controversial.

Aims

To study the influence of HBV viral factors on prognoses for patients with HBV-induced HCC after resection surgery and investigate if antiviral therapy could counteract the adverse effects of viral factors.

Methods

A total of 333 HBV-related HCC patients who underwent tumor resection were enrolled retrospectively. Serum HBV DNA levels, mutations, anti-viral therapy, and other clinical variables were analyzed for their association with post-operative recurrence.

Results

After a median follow-up of 45.9 months, 208 patients had HCC recurrence after resection. The 5-year overall survival and recurrence-free survival rates were 55.4% and 35.3%, respectively. Multivariate analysis showed indocyanine green retention rate at 15 minutes >10%, gamma-glutamyltransferase (GGT) level >60 U/L, macroscopic and microscopic venous invasion, and the absence of anti-viral therapy were significant risk factors for recurrence. Anti-viral therapy could decrease recurrence in patients with early stage HCC, but the effect was less apparent in those with the Barcelona-Clinic Liver Cancer stage C HCC. For patients without antiviral therapy after resection, serum HBV DNA levels >10⁶ copies/mL, GGT >60 U/L, and macroscopic and microscopic venous invasion were significant risk factors predicting recurrence. Among the 216 patients without anti-viral therapy but with complete HBV surface gene mapping data, 73 were with pre-S deletion mutants. Among patients with higher serum HBV DNA levels, those with pre-S deletion had significantly higher rates of recurrence. Moreover, multivariate analysis showed multi-nodularity, macroscopic venous invasion, cirrhosis, advanced tumor cell differentiation, and pre-S deletion were significant risk factors predictive of recurrence.

Conclusions

Ongoing HBV viral replication and pre-S deletion are crucial for determining post-operative tumor recurrence. Anti-viral therapy can help reduce recurrence and improve prognosis, especially for those with early stage HCC.     

Risk Factors for Progressive Visual Field Loss in Primary Angle-Closure Glaucoma: A Retrospective Cohort Study

Purpose

To investigate risk factors associated with progressive visual field (VF) loss in primary angle closure glaucoma (PACG).

Methods

We retrospectively reviewed medical record of PACG patients who had ≥5 reliable VF examinations (central 24-2 threshold test, Humphrey Field Analyzer) and ≥2 years of follow-up. Each VF was scored using Collaborative Initial Glaucoma Treatment Study system. Progression was defined if 3 consecutive follow-up VF tests had an increased score of ≥3 above the mean of the first 2 VF scores. Factors associated with VF progression were evaluated by Cox proportional hazards models.

Results

A total of 89 eyes from 89 patients (mean age, 69.8 ± 7.9 years), who received a mean of 6.9 ± 2.3 VF tests (mean deviation at initial, -8.1 ± 4.4 dB) with a mean follow-up of 63.9 ± 23.9 months were included. VF progression was detected in 9 eyes (10%). The axial length (AL), anterior chamber depth, and intraocular pressure (IOP) in patients with and without progression were 22.5 ± 0.6 and 23.1 ± 0.9 mm, 2.5 ± 0.3 and 2.5 ± 0.3 mm, 14.8 ± 2.4 and 14.3 ± 2.3 mm Hg, respectively. AL was the only factor associated with progression in both Cox proportional hazards univariate (p = 0.031) and multivariate models (p = 0.023).

Conclusion

When taking into account age, IOP, follow-up period, and number of VF tests, a shorter AL is the only factor associated with VF progression in this cohort of Chinese patients with PACG. Further studies are warranted to verify the role of AL in progressive VF loss in PACG.     

A Novel Cell-Penetrating Peptide Derived from Human Eosinophil Cationic Protein

Cell-penetrating peptides (CPPs) are short peptides which can carry various types of molecules into cells; however, although most CPPs rapidly penetrate cells in vitro, their in vivo tissue-targeting specificities are low. Herein, we describe cell-binding, internalization, and targeting characteristics of a newly identified 10-residue CPP, denoted ECP^32–41, derived from the core heparin-binding motif of human eosinophil cationic protein (ECP). Besides traditional emphasis on positively charged residues, the presence of cysteine and tryptophan residues was demonstrated to be essential for internalization. ECP^32–41 entered Beas-2B and wild-type CHO-K1 cells, but not CHO cells lacking of cell-surface glycosaminoglycans (GAGs), indicating that binding of ECP^32–41 to cell-surface GAGs was required for internalization. When cells were cultured with GAGs or pre-treated with GAG-digesting enzymes, significant decreases in ECP^32–41 internalization were observed, suggesting that cell-surface GAGs, especially heparan sulfate proteoglycans were necessary for ECP^32–41 attachment and penetration. Furthermore, treatment with pharmacological agents identified two forms of energy-dependent endocytosis, lipid-raft endocytosis and macropinocytosis, as the major ECP^32–41 internalization routes. ECP^32–41 was demonstrated to transport various cargoes including fluorescent chemical, fluorescent protein, and peptidomimetic drug into cultured Beas-2B cells in vitro, and targeted broncho-epithelial and intestinal villi tissues in vivo. Hence this CPP has the potential to serve as a novel vehicle for intracellular delivery of biomolecules or medicines, especially for the treatment of pulmonary or gastrointestinal diseases.