Effect of calcium channel blockers on experimentally induced seizures in rats

Chemically different classes of calcium channel blockers were examined in rats for their effects on behavior, tolerability and protection against maximal electroshock seizures (MES) and pentylenetetrazol (PTZ) induced seizures. In MES test at doses (mg/kg, ip) that were devoid of side effects, felodipine, 50, afforded 100% protection, while nimodipine, 5; pimozide, 10; and thioridazine, 25, showed 50 to 66% protection. Nifedipine, 10, and diltiazem, 50, showed 30 and 66% protection respectively, but were associated with side effects. Verapamil and loperamide were ineffective against MES and PTZ induced seizures. Nimodipine, 1 mg/kg, ip, was the most potent agent and produced 100% protection against PTZ. Equieffective doses were pimozide, 25, felodipine, 50, and thioridazine, 50. The rest of the calcium channel blockers showed marginal to moderate activity against chemoshock. The data obtained suggest that some calcium channel blockers possess anticonvulsant activity and may be considered as adjuvant therapeutic agents in epileptics refractory to conventional antiepileptic medication.     

C-cell in vestiges of the ultimobranchial body in human thyroid glands.

Calcitonin-containing cells were demonstrated in the so-called solid cell nests of three human thyroid glands, which supports the theory of the ultimobranchial origin of these cell nests.     

The non-canonical functions of p27Kip1 in normal and tumor biology

p27^Kip1 was first discovered as a key regulator of cell proliferation. The canonical function of p27^Kip1 is inhibition of cyclin-dependent kinase (CDK) activity. In addition to its initial identification as a CDK inhibitor, p27^Kip1 has also emerged as an intrinsically unstructured, multifunctional protein with numerous non-canonical, CDK-independent functions that exert influence on key processes such as cell cycle regulation, cytoskeletal dynamics and cellular plasticity, cell migration, and stem-cell proliferation and differentiation. Many of these non-canonical functions, depending on the cell-specific contexts such as oncogenic activation of signaling pathways, have the ability to turn pro-oncogenic in nature and even contribute to tumor-aggressiveness and metastasis. This review discusses the various non-canonical, CDK-independent mechanisms by which p27^Kip1 functions either as a tumor-suppressor or tumor-promoter.     

Plant latex thrombin-like cysteine proteases alleviates bleeding by bypassing factor VIII in murine model

Hemostasis is a tightly regulated process which maintains a fluid state of blood within the vasculature and provides thrombotic response upon tissue injury. Various scientific studies have implicated the role of plant latex proteases in hemostasis using in vitro experiments. However, in vivo models substantiate their role in hemostasis. Therefore, in the present study, the effect of plant latex thrombin-like proteases (PTLPs) on hemostasis was investigated systematically using mice tail bleeding as a preclinical model. In this direction, latex protease fractions (LPFs), which showed potent thrombin-like activity, were selected as they act directly on fibrinogen to form clot and quickly stop bleeding. Thrombin-like activity was exhibited mainly by cysteine proteases. Calotropis gigantea, Carica papaya, Jatropha curcas, Oxystelma esculentum, Tabernaemontana divaricata, and Vallaris solanacea LPFs and papain from C. papaya latex significantly reduced bleeding on a topical application in normal and aspirin administered mice. In addition, PTLPs accelerated the clotting of factor VIII deficient plasma, while, papain brought back the clotting time to normal levels acting like a bypassing agent. Further, papain failed to show activity in the presence of specific cysteine protease inhibitor iodoacetic acid; confirming protease role in all the activities exhibited. At the tested dose, PTLPs except C. gigantea did not show toxicity. Further, structural and sequence comparison between PTLPs and human thrombin revealed structural and sequence dissimilarity indicating their unique nature. The findings of the present study may open up a new avenue for considering PTLPs including papain in the treatment of bleeding wounds.     

Identification,functional characterization,assembly and structure of ToxIN type III toxin–antitoxin complex from E. coli

Toxin–antitoxin (TA) systems are proposed to play crucial roles in bacterial growth under stress conditions such as phage infection. The type III TA systems consist of a protein toxin whose activity is inhibited by a noncoding RNA antitoxin. The toxin is an endoribonuclease, while the antitoxin consists of multiple repeats of RNA. The toxin assembles with the individual antitoxin repeats into a cyclic complex in which the antitoxin forms a pseudoknot structure. While structure and functions of some type III TA systems are characterized, the complex assembly process is not well understood. Using bioinformatics analysis, we have identified type III TA systems belonging to the ToxIN family across different Escherichia coli strains and found them to be clustered into at least five distinct clusters. Furthermore, we report a 2.097 Å resolution crystal structure of the first E. coli ToxIN complex that revealed the overall assembly of the protein-RNA complex. Isothermal titration calorimetry experiments showed that toxin forms a high-affinity complex with antitoxin RNA resulting from two independent (5′ and 3′ sides of RNA) RNA binding sites on the protein. These results further our understanding of the assembly of type III TA complexes in bacteria.     

Livers with Constitutive mTORC1 Activity Resist Steatosis Independent of Feedback Suppression of Akt

Insulin resistance is an important contributing factor in non-alcoholic fatty liver disease. AKT and mTORC1 are key components of the insulin pathway, and play a role in promoting de novo lipogenesis. However, mTORC1 hyperactivity per se does not induce steatosis in mouse livers, but instead, protects against high-fat diet induced steatosis. Here, we investigate the in vivo mechanism of steatosis-resistance secondary to mTORC1 activation, with emphasis on the role of S6K1-mediated feedback inhibition of AKT. Mice with single or double deletion of Tsc1 and/or S6k1 in a liver-specific or whole-body manner were generated to study glucose and hepatic lipid metabolism between the ages of 6–14 weeks. Following 8 weeks of high-fat diet, the Tsc1-/-;S6k1-/- mice had lower body weights but higher liver TG levels compared to that of the Tsc1-/- mice. However, the loss of S6k1 did not relieve feedback inhibition of Akt activity in the Tsc1-/- livers. To overcome Akt suppression, Pten was deleted in Tsc1-/- livers, and the resultant mice showed improved glucose tolerance compared with the Tsc1-/- mice. However, liver TG levels were significantly reduced in the Tsc1-/-;Pten-/- mice compared to the Pten-/- mice, which was restored with rapamycin. We found no correlation between liver TG and serum NEFA levels. Expression of lipogenic genes (Srebp1c, Fasn) were elevated in the Tsc1-/-;Pten-/- livers, but this was counter-balanced by an up-regulation of Cpt1a involved in fatty acid oxidation and the anti-oxidant protein, Nrf2. In summary, our in vivo models showed that mTORC1-induced resistance to steatosis was dependent on S6K1 activity, but not secondary to AKT suppression. These findings confirm that AKT and mTORC1 have opposing effects on hepatic lipid metabolism in vivo.     

A rare case of congenital heart disease with ambiguous genitalia

Birth defects have become the important cause of mortality and morbidity in the perinatal period. Congenital heart disease (CHD) is the most common birth defect which includes the varying forms of cardiac abnormalities and occurs with an incidence of 1 per 100 live births. In most of the cases, CHD is an isolated malformation, but about 33% have associated anomalies. Ambiguous genitalia are one such rare anomaly that is associated with CHD among other genital abnormalities. The possible causes for this association could be pseudohermaphroditism, which in turn, may be due to congenital adrenal hyperplasia. The government of any country should consider providing for its people a free prenatal diagnosis for susceptible disorders.     

Decreased GABA receptor in the cerebral cortex of epileptic rats: effect of Bacopa monnieri and Bacoside-A

Abstact

Background

Gamma amino butyric acid (GABA), the principal inhibitory neurotransmitter in the cerebral cortex, maintains the inhibitory tones that counter balances neuronal excitation. When this balance is perturbed, seizures may ensue.

Methods

In the present study, alterations of the general GABA, GABA_A and GABA_B receptors in the cerebral cortex of the epileptic rat and the therapeutic application of Bacopa monnieri were investigated.

Results

Scatchard analysis of [³H]GABA, [³H]bicuculline and [³H]baclofen in the cerebral cortex of the epileptic rat showed significant decrease in B_max (P < 0.001) compared to control. Real Time PCR amplification of GABA receptor subunits such as GABA_Aά1, GABA_Aγ, GABA_Aδ, GABA_B and GAD where down regulated (P < 0.001) in epileptic rats. GABA_Aά5 subunit and Cyclic AMP responsible element binding protein were up regulated. Confocal imaging study confirmed the decreased GABA receptors in epileptic rats. Epileptic rats have deficit in radial arm and Y maze performance.

Conclusions

Bacopa monnieri and Bacoside-A treatment reverses epilepsy associated changes to near control suggesting that decreased GABA receptors in the cerebral cortex have an important role in epileptic occurrence; Bacopa monnieri and Bacoside-A have therapeutic application in epilepsy management.