Dengue causing fulminant hepatitis in a hepatitis B virus carrier

Dengue is an acute febrile illness resulting from infection by a flavivirus transmitted by the Aedes mosquito. It is characterized by bleeding manifestations and a plasma leak syndrome. Hepatic involvement in the form of elevation in transaminases is common. However, acute hepatic failure is uncommon. It is not known how the presence of an underlying chronic hepatitis or liver disease affects the likelihood of severity of hepatitis from dengue. The present report is of a 33-year-old man, a carrier of hepatitis B virus, who presented with fever, altered sensorium, thrombocytopenia, and coagulopathy. He was diagnosed to have developed acute hepatic failure due to dengue. The patient improved with supportive measures.

Metformin attenuates ovarian cancer cell growth in an AMP-kinase dispensable manner

Metformin, the most widely used drug for type 2 diabetes activates 59 adenosine monophosphate (AMP)-activated protein kinase (AMPK), which regulates cellular energy metabolism. Here, we report that ovarian cell lines VOSE, A2780, CP70, C200, OV202, OVCAR3, SKOV3ip, PE01 and PE04 predominantly express -α₁, -β₁, -γ₁ and -γ₂ isoforms of AMPK subunits. Our studies show that metformin treatment (1) significantly inhibited proliferation of diverse chemo-responsive and -resistant ovarian cancer cell lines (A2780, CP70, C200, OV202, OVCAR3, SKVO3ip, PE01 and PE04), (2) caused cell cycle arrest accompanied by decreased cyclin D1 and increased p21 protein expression, (3) activated AMPK in various ovarian cancer cell lines as evident from increased phosphorylation of AMPKα and its downstream substrate; acetyl co-carboxylase (ACC) and enhanced β-oxidation of fatty acid and (4) attenuated mTOR-S6RP phosphorylation, inhibited protein translational and lipid biosynthetic pathways, thus implicating metformin as a growth inhibitor of ovarian cancer cells. We also show that metformin-mediated effect on AMPK is dependent on liver kinase B1 (LKB1) as it failed to activate AMPK-ACC pathway and cell cycle arrest in LKB1 null mouse embryo fibroblasts (mefs). This observation was further supported by using siRNA approach to down-regulate LKB1 in ovarian cancer cells. In contrast, met formin inhibited cell proliferation in both wild-type and AMPKα_1/2 null mefs as well as in AMPK silenced ovarian cancer cells. Collectively, these results provide evidence on the role of metformin as an anti-proliferative therapeutic that can act through both AMPK-dependent as well as AMPK-independent pathways.

Broken chain effect in doped SrCuO2

We report the effect of magnetic (Ni) and nonmagnetic (Zn, Ga) doping on the overall magnetic behaviour of the spin chain compound SrCuO(2). The doping causes systematic reduction in the intrachain exchange interaction, and the influence is found to be almost independent of the dopant. The low temperature Curie tail in the temperature dependence of susceptibility also increases with the doping concentration, which is an indication of the enhanced chain breaking effect with doping. The doping also gives rise to nonlinearity in the isothermal magnetization behaviour, which can be accounted for by the effect of free/quasi-free spin in the doped sample. Our analysis indicates that doped Ni(2+) ions remain in a low spin state (S = 0) and behave almost similar to the nonmagnetic counterpart as far as the doping effects are concerned.

Structural and magnetic properties of spontaneously phase-separated Eu0.5Sm0.5MnO3

We have studied structural and magnetic properties of Eu(0.5)Sm(0.5)MnO(3). The system shows strong orthorhombic distortion. The static Jahn-Teller effect modifies the low temperature magnetic properties, creating a complicated anisotropic magnetic ground state. A low temperature magnetic phase separation has also been realized that builds magnetic interfaces exhibiting strong exchange bias. Careful analysis of the magnetic behaviour indicates the origin of the exchange bias to be a phase separation between an A-type antiferromagnetic phase and a low temperature highly anisotropic phase originating from another ordering at the rare-earth sublattice.

Exchange bias effect in alloys and compounds

The phenomenology of exchange bias effects observed in structurally single-phase alloys and compounds but composed of a variety of coexisting magnetic phases such as ferromagnetic, antiferromagnetic, ferrimagnetic, spin-glass, cluster-glass and disordered magnetic states are reviewed. The investigations on exchange bias effects are discussed in diverse types of alloys and compounds where qualitative and quantitative aspects of magnetism are focused based on macroscopic experimental tools such as magnetization and magnetoresistance measurements. Here, we focus on improvement of fundamental issues of the exchange bias effects rather than on their technological importance.

Unusual magnetocaloric effect in R2Al (R = Dy, Ho, Er) compounds

The magnetic properties of the orthorhombic intermetallic compounds R(2)Al (R = Dy, Ho, Er) are reported. Dy(2)Al undergoes a long-range canted antiferromagnetic-type ordering below T(1) = 105 K, and a further spin reorientation-type ordering below T(2) = 33 K. The low temperature magnetic state of the sample is found to be quite unusual, where a large hysteresis loop is observed in the magnetization curves (coercive field ∼ 33 kOe at 2 K). The isostructural compositions Ho(2)Al and Er(2)Al show multiple magnetic transitions: however, they do not show a large hysteresis loop at low temperature. Dy(2)Al is also associated with an interesting magnetocaloric effect, which is negative and moderate around T(1), but becomes large and positive below T(2). The observed behavior is related to the large magnetocrystalline anisotropy and narrow domain wall propagation coupled with a field-induced state at low temperature.

Dirichlet boundary conditions and effect of confinement on chemical reactivity

To understand the source of discrepancy in the qualitative trends in the reactivity of the spherically confined atoms/ions when the high pressure is generated through the use of a proper Dirichlet boundary condition [J. Chem. Sci. 2005, 117, 379; Phys. Chem. Chem. Phys. 2008, 10, 1406] and of a cutoff function [Chem. Phys. Lett. 2003, 372, 805; J. Phys. Chem. A 2003, 107, 4877], a modified Herman-Skilman program is run. Results obtained from different formulas of reactivity parameters are analyzed. Change in reactivity for different electronic configurations is also reported. It is observed that the use of different formulas is the major source of discrepancy and not the Dirichlet condition, although the latter is highly recommended. As the cutoff radius of the confining spherical box decreases, the energy of the atom/ion increases, the electronegativity decreases, and the hardness increases and ultimately slightly decreases in an ultraconfined situation. For small R(C) values, softness decreases and electrophilicity increases and attains relatively small values. The reactivity of confined atoms/ions is put in a proper perspective.

Grain size effect on the magnetic cluster-glass properties of La0.88Sr0.12CoO3

We report the grain size effect of hole-doped cobaltite, La(0.88)Sr(0.12)CoO(3), where average sizes are varied from ∼35 to ∼240 nm. The bulk compound is a cluster-glass (CG) compound composed of short range ferromagnetic (FM) clusters embedded in the spin-glass (SG) matrix at low temperature. The short range FM clusters are still retained in the nanocrystalline compound with average size ∼35 nm which are associated with the SG component, displaying CG-like spin dynamics at low temperature. The exchange bias (EB) effect manifested by the shifts in the hysteresis loop is observed due to the field cooling where EB effect is weakened systematically with decreasing grain size. The decrease in the fraction of the FM component is found to be correlated with the weakening of the EB effect with decreasing grain size. Interestingly, the signature of the EB phenomenon due to the field-cooled effect is also evidenced in the temperature as well as the time dependence of resistivity. The grain interior phase separation scenario around the FM/SG interface region has been proposed to interpret the experimental results.

Exchange bias effect and intragranular magnetoresistance in Nd(0.84)Sr(0.16)CoO(3)

Electrical transport properties as a function of magnetic field and time have been investigated in polycrystalline, Nd(0.84)Sr(0.16)CoO(3). A strong exchange bias (EB) effect is observed associated with the fairly large intragranular magnetoresistance (MR). The EB effect observed in the MR curve is compared with the EB effect manifested in the magnetic hysteresis loop. A training effect, described as the decrease of EB effect when the sample is successively field cycled at a particular temperature, has been observed in the shift of the MR curve. The training effect could be analyzed by successful models. The EB effect, MR and a considerable time dependence in MR are attributed to the intrinsic nanostructure giving rise to varieties of magnetic interfaces in the grain interior.

Anomalous magneto-transport behaviour near the first order phase transition in Gd(5)Ge(3.8)Ga(0.2) alloy

We study the effect of Ga doping at the Ge site of the metamagnetic compound Gd(5)Ge(4). For 5% Ga doping, the resulting alloy (Gd(5)Ge(3.8)Ga(0.2)) shows antiferromagnetic ordering around 130 K, and a thermally driven first order magneto-structural transition at low temperature leading to the ferromagnetic ground state. The alloy shows a noticeable amount of training effect in resistivity when thermally cycled through this first order phase transition (FOPT). The training effect is present in the case of isothermal field cycling. The FOPT region is found to be metastable and extremely sensitive to the applied magnetic field with a clear signature of a metamagnetic transition in the magnetization and resistivity. The metastability is further supported by the large relaxation observed in the resistivity. The giant magnetoresistance observed in the sample is found to be positive near the FOPT, while below the transition it is negative. The resistivity shows irreversibility due to field cycling, which is related to both a field-induced arrested state and some permanent micro-structural changes in the sample.

Effect of saponins from Helicteres isora on lipid and glucose metabolism regulating genes expression

ETHNOPHARMACOLOGICAL RELEVANCE

We characterized saponins as active constituents from traditionally used antidiabetic plant Helicteres isora.

AIM OF THE STUDY

To evaluate the changes in the gene expression of the glucose and lipid metabolism regulating genes in C57BL/KsJ-db/db mice.

MATERIALS AND METHODS

C57BL/KsJ-db/db mice were divided into four different groups; one diabetic control, the mice in other three groups were treated with methanol extract (100 mg/kg), saponins (100 mg/kg) and pioglitazone (30 mg/kg) for 14 days. After completion of the treatment period biochemical parameters and the expression levels of adipsin, adiponectin, glucose transporter 4 (Glut4), peroxisome proliferator activated receptor gamma (PPARgamma), fatty acid binding protein 4 (FABP4), lipoprotein lipase (LPL) in adipose tissue and for liver RNA samples glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), glucose transporter 2 (Glut2) and acyl-co-enzyme A oxidase (ACOX) were determined by quantitative real time PCR and angiopoeitin like 3 (ANGPTL3), angiopoeitin like 4 (ANGPTL4) and peroxisome proliferator activated receptor alpha (PPARalpha) by semiquantitative reverse transcription PCR.

RESULTS

Treatment caused a significant reduction in the serum lipid and glucose levels and increased the expression of adipsin, PPARgamma and Glut4 while reduced expression of FABP4 and G6Pase, whereas there was no effect on the expression levels of adiponectin, LPL, PEPCK, ACOX, Glut2, ANGPTL3, ANGPTL4 and PPARalpha.

CONCLUSIONS

Saponins are beneficial for improving hyperlipidemia and hyperglycemia by increasing the gene expression of adipsin, Glut4 and PPARgamma and reducing the gene expression of the enzyme G6Pase and FABP4 in C57BL/KsJ-db/db mice.

Activation of AMPK inhibits inflammation in MRL/lpr mouse mesangial cells

Recent reports show that 5-amino-4-imidazole carboxamide riboside (AICAR), a pharmacological activator of AMP-activated protein kinase (AMPK), inhibits the lipopolysaccharide (LPS)-induced production of proinflammatory cytokines. MRL/MPJ-Fas(lpr) (MRL/lpr) mice show an intrinsic decreased threshold for the production of inflammatory mediators when stimulated. In our current studies, we sought to determine if AMPK activation would inhibit inflammatory mediator production in stimulated kidney mesangial cells. Cultured mesangial cells from MRL/lpr mice were treated with AICAR and stimulated with LPS/interferon (IFN)-gamma. AICAR decreased dose-dependently inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and interleukin-6 production in LPS/IFN-gamma-stimulated mesangial cells. Mechanistically, AICAR inhibited the LPS/IFN-gamma-stimulated PI3K/Akt signalling inflammatory cascade but did not affect LPS/IFN-gamma-mediated inhibitory kappa B phosphorylation or nuclear factor (NF)-kappaB (p65) nuclear translocation. Treatment with the adenosine kinase inhibitor 5'-iodotubercidin blocked the ability of AICAR to activate AMPK and prevented AICAR from inhibiting the LPS/IFN-gamma-stimulated PI3K/Akt pathway and attenuating iNOS expression. Taken together, these observations suggest that AICAR inhibits LPS/IFN-gamma-induced Akt phosphorylation through AMPK activation and may serve as a potential therapeutic target in inflammatory diseases.

The exchange bias effect in phase separated Nd(1-x)Sr(x)CoO(3) at the spontaneous ferromagnetic/ferrimagnetic interface

We report new results for the exchange bias effect in Nd(1-x)Sr(x)CoO(3) for x = 0.20 and 0.40, where the exchange bias phenomenon is involved with the ferrimagnetic (FI) state in a spontaneously phase separated system. The zero-field-cooled magnetization exhibits FI (T(FI)) and ferromagnetic (FM; T(C)) transitions at ∼23 and ∼70 K, respectively, for x = 0.20. Negative horizontal and positive vertical shifts of the magnetic hysteresis loops are observed when the system is cooled through T(FI) in a positive static magnetic field. A training effect is observed for x = 0.20, which could be interpreted satisfactorily by the spin configurational relaxation model. The unidirectional shifts of the hysteresis loops as a function of temperature exhibit an absence of exchange bias above T(FI) for x = 0.20. Analysis of the cooling field dependence of the exchange bias field and magnetization indicates that the FM clusters consist of a single magnetic domain with an average size of around ∼20 and ∼40 Å for x = 0.20 and 0.40, respectively. The sizes of the FM clusters are close to the percolation threshold for x = 0.20; these grow and coalesce to form the bigger size for x = 0.40 resulting in a weak exchange bias effect.

Reply to comment on 'Particle size dependent exchange bias and cluster-glass states in LaMn(0.7)Fe(0.3)O(3) '

In reply to the comment by Geshev we emphasize that loop shift in the compounds is not a simplified phenomenon of minor loop effect of a ferromagnet rather, it is a genuine signature of exchange bias effect. The estimate of anisotropy field and the plot of exchange bias field at 5 K with the maximum field used for the measurement of hysteresis loop, in addition to the previously reported results such as temperature dependence of exchange bias field, training effect, etc, confirm the exchange bias effect.

Role and extent of neck dissection for persistent nodal disease following chemo-radiotherapy for locally advanced head and neck cancer: how much is enough?

PURPOSE

Neck dissection (ND) is routinely performed for persistent nodal disease after definitive chemo-radiotherapy (CRT) for locally advanced head and neck cancer. This study analyzes the role and extent of ND necessary after CRT based on pathologic outcome.

PATIENTS AND METHODS

The study is based on 42 patients undergoing 48 ND's for persistent nodal disease after CRT. Patients were treated to a median radiation dose of 70.4 Gy at 1.8-2 Gy per fraction concurrently with platinum based chemotherapy. Patients with documented residual disease in neck, based on clinical or radiological examination underwent ND at a median interval of 59 days after completion of CRT.

RESULTS

Of the 42 patients undergoing ND, 11 (26%) had positive findings on pathologic evaluation. The clinical and treatment characteristics were similar for node negative and positive patients. The involved nodal level(s) were always confined within the clinically documented persistent disease. The median percentage of positive nodes to total nodes removed was 10%. Almost 50% of positive nodes removed had only microscopic or minute viable cancer pathologically. The outcome was better for pathologically node negative patients in comparison to node positive patients.

CONCLUSION

The results of this study suggest that standard ND appears to be an excessive treatment for persistent nodal disease after CRT. Limited ND or even gross nodal resection confined to involved nodal level(s) as identified clinically or radiologically should be tested in a prospective randomized trial for reducing treatment related morbidity while maintaining excellent loco-regional control.

A role for candidate tumor-suppressor gene TCEAL7 in the regulation of c-Myc activity, cyclin D1 levels and cellular transformation

The pathophysiological mechanisms that drive the development and progression of epithelial ovarian cancer remain obscure. Recently, we identified TCEAL7 as a transcriptional regulatory protein often downregulated in epithelial ovarian cancer. However, the biological significance of such downregulation in cancer is not currently known. Here, we show that TCEAL7 is downregulated frequently in many human cancers and that in immortalized human ovarian epithelial cells this event promotes anchorage-independent cell growth. Mechanistic investigations revealed that TCEAL7 associates with cyclin D1 promoter containing Myc E-box sequence and transcriptionally represses cyclin D1 expression. Moreover, downregulation of TCEAL7 promotes DNA-binding activity of Myc-Max, and upregulates the promoter activity of c-Myc-target gene, ornithine decarboxylase (ODC), whereas enhanced expression of TCEAL7 inhibits Myc-induced promoter activity of ODC. Our findings suggest that TCEAL7 may restrict ovarian epithelial cell transformation by limiting Myc activity. These results also suggest a potential, alternative mechanism by which c-Myc activity may be deregulated in cancer by the downregulation of TCEAL7.