Fungal biomolecules assisted biosynthesis of Au-Ag alloy nanoparticles and evaluation of their catalytic property.

The catalytic reduction of methylene blue was studied using biosynthesised gold-silver (Au-Ag) alloy nanoparticles (NPs). The fungal biomass of Trichoderma harzianum was used as a reducing and stabilising agent in the synthesis of Au-Ag alloy NPs. The synthesised NPs were well characterised by UV-vis spectroscopy, dynamic light scattering, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The plausible synthesis mechanism involved in the formation of Au-Ag alloy NPs was also discussed with diagrammatic representation. A series of experiments was performed to investigate the catalytic activity of the as-prepared Au-Ag alloy NPs and found that the alloy NPs show excellent catalytic activity.

Gallbladder cancer incidence in Gwalior district of India: Five-year trend based on the registry of a regional cancer center.

BACKGROUND: We have reported here the 5-year incidence (2004-2008) of gallbladder cancer (GBC) in North Central India along with its descriptive epidemiology. This provides potential clues for better prevention. The present study has also evaluated the association of ABO blood groups with GBC. PATIENTS AND METHODS: The study comprised 742 GBC cases referred to the regional cancer hospital, Gwalior, during 2004-2008. The demographic statistics of Gwalior district was considered to calculate the relative risk and incidence rates. ABO blood group distribution amongst 90,000 healthy subjects registered in the local blood bank during 2002-2007 was taken as controls to study the association of blood groups with GBC. RESULTS: The age-standardized total incidence rate of GBC was calculated to be 7.16/1,00,000. The relative risk of females getting GBC was 2.693 at 95% confidence interval of 2.304-3.151 (P < 0.0001). The females formed 69.5% of total cancer cases, with age-standardized incidence rate of 10/1,00,000. The mean age of male and female GBC cases was found to be 55.4 years (SD = 13, SE = 0.77) and 51.5 years (SD = 12.3, SE = 0.50), respectively. The blood groups A (P = 0.0022) and AB (P < 0.0001) had a positive association with GBC with significant level of differences in comparison to controls. CONCLUSION: Our study provided an estimate of a 5-year incidence of GBC in North Central India for the first time. With regard to the association of risk factors like obesity, age, and urban living with GBC, the findings of the present study are contradictory to the general opinion. Blood groups A and AB were found to be associated with GBC, which would be provisional for further investigations.

Biogenic gold nanoparticles: As a potential candidate for brain tumor directed drug delivery.

Gold nanoparticles have tremendous application in the area of nanotechnology that raises new possibility in the treatment of brain tumor. These nanoparticles can be used for selectively gaining access to tumor due to their small size and modifiability. Gold nanoparticles are functionalized with various molecules such as anticancer drug, transferrin and monoclonal antibody to produce nanocarriers. These nanocarriers have ability to deliver the drug at targeted site. Transferrin crosses the blood-brain barrier because of the receptor-mediated endocytosis. The monoclonal antibody facilitates the release of anticancer drug at targeted sites. This approach of delivery saves the normal cells surrounding the tumor.

ZnO nanoflowers: novel biogenic synthesis and enhanced photocatalytic activity.

We demonstrate a novel, unprecedented and eco-friendly mode for the biosynthesis of zinc oxide (ZnO) nanoflowers at ambient room temperature using Bacillus licheniformis MTCC 9555 and assessed their photocatalytic activity. The photocatalytic degradation of methylene blue (MB) dye was analyzed under UV-irradiation. An enhanced photocatalytic activity of ZnO nanoflowers was obtained compared to the earlier reports on ZnO nanostructures and other photocatalytic materials. The mechanism behind the enhanced photocatalytic activity was illustrated with diagrammatic representation. It is assumed that due to larger content of oxygen vacancy ZnO nanoflowers shows enhanced photocatalytic activity. Photostability of ZnO nanoflowers was analyzed for consecutive 3 cycles. The size and morphology of ZnO nanoflowers have been characterized by SEM, TEM and found to be in the size range of 250 nm to 1 µm with flower like morphology. It was found that ZnO nanoflowers was formed by agglomeration of ZnO nanorods. Further the EDX established the presence of the elemental signal of the Zn and O. XRD spectrum of ZnO nanoflowers confirmed 2θ values analogous to the ZnO nanocrystal. FTIR analysis was carried to determine the probable biomolecules responsible for stabilization of ZnO nanoflowers. The plausible mechanism behind the synthesis of ZnO nanoflowers by Bacillus licheniformis MTCC 9555 was also discussed with diagram representation.

The liver function test enzymes and glucose level are positively correlated in gallbladder cancer: a cancer registry data analysis from north central India.

AIM OF STUDY: To investigate the trend of expression of liver function test enzymes and other biochemical changes during gallbladder carcinogenesis. MATERIALS AND METHODS: Eight hundred and seventy-eight gallbladder disease patients were selected to study the liver function test enzymes and routine blood biochemical changes in the last five years (2004-08). Statistical analysis was performed using Graph Pad prism 5.02 software. RESULTS: The liver function test enzymes showed significant correlations among themselves, and with glucose in gallbladder cancer and gallstone disease patients (N = 878). Out of 878 gallbladder cases, 46 (5.24%) showed significantly higher glucose level of 216.66 mg/dL (P < 0.0001). All the three pathological conditions of gallbladder, gallbladder cancer with stones (GBCS), gallbladder cancer without stones (GBC) and calculus cholecystitis (CC), showed highly significant positive correlation (Pearson) between Serum Glutamic Oxaloactetic Transaminase (SGOT) and Serum Glutamic Pyruvic Transaminase (SGPT) [P < 0.0001, (GBCS); P < 0.0001, (GBC), and P < 0.0001, (CC)]. SGOT and SGPT also showed positive correlation with higher glucose level independently, in both GBCS and CC (P < 0.0001 and P < 0.0001), respectively. CONCLUSION: Simultaneous elevation of glucose and liver function test enzymes in GBC makes the diagnosis complex. Any patient of gallbladder diseases with higher level of glucose may have the possibility of developing gallbladder cancer.

Cellular and biophysical evidence for interactions between adenosine triphosphate and P-glycoprotein substrates: functional implications for adenosine triphosphate/drug cotransport in P-glycoprotein overexpressing tumor cells and in P-glycoprotein low-level expressing erythrocytes.

P-glycoprotein is involved with the removal of drugs, most of them cations, from the plasma membrane and cytoplasm. Pgp is also associated with movement of ATP, an anion, from the cytoplasm to the extracellular space. The central question of this study is whether drug and ATP transport associated with the expression of Pgp are in any way coupled. We have measured the stoichiometry of transport coupling between drug and ATP release. The drug and ATP transport that is inhibitable by the sulfonylurea compound, glyburide (P. E. Golstein, A. Boom, J. van Geffel, P. Jacobs, B. Masereel, and R. Beauwens, Pfluger's Arch. 437, 652, 1999), permits determination of the transport coupling ratio, which is close to 1:1. In view of this result, we asked whether ATP interacts directly with Pgp substrates. We show by measuring the movement of Pgp substrates in electric fields that ATP and drug movement are coupled. The results are compatible with the view that substrates for Pgp efflux are driven by the movement of ATP through electrostatic interaction and effective ATP-drug complex formation with net anionic character. This mechanism not only pertains to drug efflux from tumor cells overexpressing Pgp, but also provides a framework for understanding the role of erythrocytes in drug resistance. The erythrocyte consists of a membrane surrounding a millimolar pool of ATP. Mammalian RBCs have no nucleus or DNA drug/toxin targets. From the perspective of drug/ATP complex formation, the RBC serves as an important electrochemical sink for toxins. The presence in the erythrocyte membrane of approximately 100 Pgp copies per RBC provides a mechanism for eventual toxin clearance. The RBC transport of toxins permits their removal from sensitive structures and ultimate clearance from the organism via the liver and/or kidneys.

Effects of halothane and hydrostatic pressure on sodium channels in squid axon.

The effects of halothane and hydrostatic compression have been studied on the voltage-dependent sodium conductances in the squid giant axon. Compression to 150 atmospheres reduced the time course of both the activation and inactivation phases of the sodium current, reduced the amplitude of the peak inward current, and shifted the sodium reversal potential in a slightly hyperpolarizing direction. Halothane also depressed the sodium current amplitude and shifted the reversal potential but did not alter the membrane kinetics. Subsequent compression to 100 ATA did not restore the inward current flux to its control value, nor reverse the shift in the sodium reversal potential. We conclude that pressure and halothane do not act antagonistically at common sites in this preparation.

Hydrostatic pressure reduces synaptic efficiency by inhibiting transmitter release.

The amplitude of post-synaptic potentials at an identified synapse in the Aplysia central nervous system can be modulated by the application of hydrostatic pressure. Postsynaptically controlled functions, including responses to acetylcholine and the time course of decay of the synaptic responses, remain unaffected by compression. In contrast, frequency facilitation and posttetanic potentiation, which result from presynaptic processes, are altered by pressure in a manner similar to that of agents that block transmitter release. It is concluded that pressure reduces synaptic efficiency by interfering with certain presynaptic mechanisms associated with transmitter release.

A versatile high-pressure chamber for electrophysiological measurements.

A modular high-pressure chamber is described. This chamber will allow stable microelectrode recordings to be made for a variety of intracellular preparations at pressure of 200-300 atmospheres absolute. Its features include internal temperature control, easy visibility, continuous perfusion, electrical penetrations, and manipulation of several internal controls while the system is at pressure. The small size and high versatility of the Wilson chamber make it a convenient and inexpensive research unit for experiments in the moderately high-pressure ranges that affect biological preparations.

Effect of interaction of volatile anesthetics and high hydrostatic pressure on central neurons.

Autoactive neurons in the central nervous system of Helix and Aplysia were studied after exposure to several volatile anesthetics and under compression by mineral oil. Voltage clamp studies reveal that halothane will eliminate the slow inward current that underlies oscillatory activity in burster neurons, while high pressure shifts the negative resistance region of the current without causing its elimination. Simultaneous application of the anesthetic and pressure results in the loss of inward current over a time course similar to that of halothane application alone. It is concluded that in this system, pressure and anesthetics are not acting antagonistically at the site in the membrane that controls slow wave conductances.

Mechanism of ketamine block of nerve conduction.

The node of action of ketamine on the nerve membrane has been studied in intact and internally perfused squid giant axons at 10-12 degrees C. Voltage clamp techniques have been employed to measure the maximal values of peak transient and steady-state conductances as an index of activity and to measure the apparent reversal potential for peak transient current. When applied externally to intact axons, kketamine decreased the resting membrane potential, suppressed steady-state conductances and slightly decreased theleakage conductance, although the last effect was not statistically significant. Peak transient conductance was not appreciably affected. However, when the drug was applied internally, both peak transient and steady-state conductances were suppressed. Ketamine applied externally either to intact axons or to internally perfused axons with internal flow temporarily suspended shifted the apparent reversalpotential for peak transient current towards hyperpolarization. The shift was estimated to be 28.5 mV for 200 micronM ketamine. Wahing the intact axons with drug-free sea water shifted the reversal potential further towards membrane hyperploarization. However, internal washing quickly returned the reversal potential to near control value. The change in resting sodium influx caused by external exposure to ketamine was also measured by using radioactive sodium in external sea water at 10 degrees C. Ketamine (200 micronM) changed the resting sodium influx from (28.9 +/- 5.6) x 10(-12 mol/cm2-sec to (41.8 +/- 5.6) x 10(-12 mol/cm2-sec (mean +/- S.E.M.). The data presented in this paper strongly suggest that the shift in the reversal potential for peak current caused by ketamine is due partly to sodium ion accumulation inside the nerve and partly to the increase in the PR/PNa ratio during peak current. These changes would have a profound narcotic effect on the electrical activity of nerve fibers and nerve endings in the brain during ketamine anesthesia.

Active form of ketamine in squid giant axons.

The active form of ketamine has been studied with internally perfused squid qiant axons. The drug was applied internally, and decreases in peak transient and steady-state conductances as measured by voltage clamp technique were taken as an index of activity. When the total internal ketamine concentration was maintained constant, the suppression peak transient and steady-state conductances decreased with an increase in internal pH from 7.0 TO 8.4. When the concentration of the internally present charged form of ketamine was kept constant, the suppression of the peak transient conductance remained almost constant at internal pH values of 7.0, 7.3 and 7.7, but increased at pH 8.4. However, the suppression of the stead-state conductance became more prominent as the pH was raised from 7.0 to 8.4. With a constant internal concentration of the uncharged form, the suppression of both conductances decreased as the pH was raised from 7.0 to 8.4. Computation of dissociation constants to suppretamine is more potent than the charged form at all internal pH values examined. These data also show that the potency to suppress the peak transient conductance by the charged and uncharged forms of ketamine decreased as the intertance of the charged form increased, and that of the uncharged form decreased considerably with increase in the internal pH.

Mode of action of trichloroethylene on squid axon membranes.

The mode of action of trichloroethylene on electrical properties of squid giant axons has been studied by means of voltage clamp techniques. Trichloroethylene decreased the resting membrane potential in a manner dependent upon the concentration, the depolarization by 50% saturated trichloroethylene attaining 28.4 and 32.7% of the initial value at 20 and 10 degrees C, respectively. Leakage conductance was decreased to 34.6% of the control by 30% saturated trichloroethylene at 10-12 degrees C. It appears that the trichloroethylene-induced depolarization is at least in part due to a decrease in resting potassium permeability. Both peak transient and steady-state conductance increases were suppressec by trichloroethylene, and the curve relating the steady-state conductance to the membrane potential was shifted in the depolarizing direction while the peak transient conductance curve was not appreciably shifted. The reversal potential for the peak transient current was greatly shifted by trichloroethylene in the direction of hyperpolarization in a manner dependent on the concentration, the maximum shift amounting to 25 mV at 10 degrees C. This effect was less pronounced at 20 degrees C. The shift in the reversal potential is mostly due to a decrease in selectivity of the peak transient channel and partly due to an accumulation of sodium ions inside. Analyes of dose-response relation in suppressing peak transient and steady-state conductances show that trichloroethylene interacts with receptor on a one-to-one stoichiometric basis. Steady-state sodium inactivation curve was shifted by trichloroethylene in the direction of hyperpolarization. All of these effects were partially reversed after washing the axon with anesthetic-free media. The accumulation of sodium ions inside would be much more pronounced in small nerve fibers in the brain than in giant axon and, together with the observed decrease in the selectivity of peak transient channels, would play a significant role in general anesthesia.