Anti-ulcer activity of arachidonic acid (PUFA) oils in different induced ulcer animal models.

Background: Ulcers of the lower part of the oesophagus, the stomach and the first part of the duodenum are also known as peptic ulcers. Peptic ulcers can affect people of any age, but they are more common as you get older. There is a focus on research for better tolerated and efficacious anti-ulcer agents. Methods: Effect of anti-ulcer activity of fish oil and Arasco oil was evaluated in different animal models of ulcers i.e. ethanol induced, water immersion and pyloric ligation techniques. The Superoxide dismutase activity in gastric tissue was also ascertained in two groups of animals. The animals received either fish oil (40 μl, PO), Arasco oil (40 μl, PO), omeprazole (20 mg/kg PO) or ranitidine (30 mg/kg PO). The gastro-protection was calculated based on ulcer index, pH and gastric juice volume. Results: The results of this study suggest that poly unsaturated fatty acid (PUFA) contained in fish oil and Arasco oil have moderate anti-ulcer activity although probably lesser in potency than the available anti-ulcer drugs like omeprazole and ranitidine. Conclusion: These results have shown that PUFA containing oils provided moderate gastrointestinal protection in all the induced ulcer models employed. Thus it can be concluded that PUFA containing oils like the Fish oil and Arasco oil have anti-ulcer properties and the mechanisms involved in these actions need to be investigated.

Cardiovascular and biochemical studies on the effects of thrombin and dabigatran and the interaction with vasopressor molecules.

Background: The effect of serine protease thrombin and its directly acting inhibitor dabigatran were evaluated on the heart rate, blood pressure, and phospholipase C (PLC) enzyme activity and the intracellular calcium levels in the platelets. Methods: Heart rate and blood pressure were estimated using electrophysiology equipment. Results: While thrombin was unable to significantly affect the heart rate and blood pressure, the inhibitor dabigatran was able to reduce the heart rate appreciably but its effects on the blood pressure were minimal. The thrombin induced increase in PLC enzyme activity, and intracellular calcium levels were attenuated by dabigatran in the platelets. The posterior pituitary hormone, vasopressin, and the adrenergic agonist noradrenaline were used to stimulate the PLC and calcium levels in platelets. Conclusion: The thrombin inhibitor, dabigatran reduces vascular oxidative stress and inflammation, improves endothelial function, and decreases atherosclerosis in rodents.

Lipoprotein associated phospholipase A2 enzyme; possible new roles and inhibition for therapeutic intervention.

Lipoprotein-Associated Phospholipase A2 (Lp-PLA2) is a 45-kDa protein of 441 amino acids encoded by the pla2g7 gene in the humans. In the blood it is associated mainly with Low Density Lipoprotein (LDL) and less than 20% is associated with High Density Lipoprotein (HDL). This enzyme is characterized by its ability to specifically hydrolyze PAF as well as glycerophospholipids containing short, truncated, and/or oxidized fatty acyl groups at the sn-2 position of the glycerol backbone. Genetic studies conducted in humans harboring an inactivating mutation at this locus suggest that loss of Lp-PLA2 function is a risk factor for inflammatory and vascular conditions. Consistently, overexpression of Lp-PLA2 has anti-inflammatory or pro-inflammatory actions and anti-atherogenic properties in animal models. This article discusses two simple techniques to estimate Lp-PLA2 activity. New therapeutic agents inhibiting the activity of Lp-PLA2 are being investigated for curative purpose.

R-Loop Hybrid Structure Formation and their Role in Health and Disease; Possible Implications for Unusual Nucleic Acid Structure Formation.

The R-loop is a stable RNA–DNA hybrid structure in which the RNA strand is base-paired with one DNA strand of a DNA duplex, leaving the opposite DNA strand single-stranded. This structure can be involved in the hypermutation and double stranded DNA breaks in mammalian immunoglobulin (Ig) genes, oncogenes and neurodegenerative disease related genes. R-loops have not been studied at the genome scale extensively. It has been shown that many oncogenes and tumour suppressors (e.g. Tp53, BRCA1, BRCA2 and Ptprd) and neurodegenerative diseases related genes (e.g. ATM, Park2, and GLDC) could be prone to significant R-loop formation. The recent findings suggest that R-loops provide a novel level of RNA–DNA interactome complexity, playing key roles in gene expression controls, mutagenesis, recombination process, chromosomal rearrangement, alternative splicing, DNAediting a R-loops have been described in vivo at the immunoglobulin class switch sequences and at prokaryotic and mitochondrial origins of replication. However, the biochemical mechanism and determinants of R-loop formation are unclear and how also they can affect epigenetic modifications needs to be elucidated. R-loop hybrid structure could be used as a novel source of prospective therapeutic targets.

Evaluation of the effect of metformin on the inhibitory effect of oxytocin on potassium chloride stimulated goat ileum.

The posterior pituitary hormone, oxytocin is expressed in the myenteric and submucous ganglia and nerve fi bers along the entire human gastrointestinal (GI) tract. The role for oxytocin in the physiology and pathophysiology of the bowel remains to be clearly elucidated. Many studies have described that oxytocin exerts stimulatory or inhibitory effects on gut functions. Recently, mRNA for oxytocin and its receptor was found throughout the entire human GI tract. In this study, we examined the responses of the posterior pituitary hormone, oxytocin on the contractile responses to KCl and the effect of metformin on these responses as it affects the glucose transport and causes monoamine release in the gut.

The Influence of Epithelial Sodium Channels in Isolated Goat Ileum Segment; Interaction with Steroids.

The contractile effect of Acetylcholine (Ach) in the isolated longitudinal ileal muscle of adult goats was studied over a varying concentration range. Ach produced a concentration dependent-response curve indicative of an interaction with muscarinic receptors in the ileum, with a maximum contraction seen at 12 μM. On the other hand, pretreatment with the ENaC blocker, Amiloride (100 μM) substantially reduced the Ach induced contractions by 67.11 %. However, pretreatment with Prednisolone (2mM) restored this effect and the relaxation induced was only 14.26 %. This change was found to be statistically significant. This study emphasizes the importance of ENaC channels in the goat intestinal smooth muscle.

ABL Tyrosine Kinases and DNA Methylation May Mediate in High Glucose Induced Hyperosmolality; Role of Target Proteins.

Phosphorylation of proteins on their threonine, serine, and tyrosine residues is one of the most commonly occurring posttranslational modifications in eukaryotic cells. Cellular phosphorylation cascades facilitates the amplification of extracellular signals following changes in environmental conditions via the ability of phosphorylated activators to modulate the expression of numerous genes. Because these reactions are rapidly reversible, they are important for the regulation of many cellular functions including signal transduction, cell division, and proliferation. Hyperosmolality can induce tyrosine phosphorylation of TonEBP/OREBP. Tyrosine phosphorylation by Abl kinases of several target proteins is a key mechanism for modulating signal transduction in hyperosmolar conditions. In this review article we discuss the role of Abl tyrosine kinases and DNA methylation during glucose induced hyperosmolality.

Application of Liquid Chromatography-Mass Spectrometry for Detecting Terlipressin Levels in Rat Plasma.

This work describes a liquid chromatography– electrospray tandem mass spectrometry method for detection of terlipressin in Wistar rat plasma in the low nano-gram range. Terlipressin is a synthetic analogue of the antidiuretic hormone arginine vasopressin and it might be used when Arginine vasopressin (AVP) is not readily available. For experimental evaluation of the pharmacokinetics of terlipressin, rats can be injected 3.0 μg/kg or 6.0 μg/kg i.v. of terlipressin and blood can be collected for Mass spectrometry characterization of terlipressin which can be performed with a high-resolution Orbitrap-based mass spectrometer.

Biosynthesis of silver nano-particles by the bacterium micrococcus luteus.

Nanotechnology is the application of science to control matter at the molecular level. It is a field that is burgeoning in the recent times, making an impact in all spheres of human life. Microorganisms play an important role in the eco-friendly synthesis of metal nanoparticles. The use of microorganisms for the synthesis of nanoparticles in the lime light of modern nanotechnology is a novel approach. Biological methods of synthesis have paved the way for the greener synthesis of these nanoparticles which can have application in biomedical sciences. In this study, we report the synthesis of nanoparticles of silver by the reduction of aqueous Ag+ by a culture of Micrococcus luteus. The formation of silver nano-particles was monitored by X-ray diffraction spectroscopy (XRD) and elucidated by transmission electron microscopy (TEM).

Is oxytocin a key hormone for gene regulation and physiological function in postmenopausal women; an inquest into possible mechanisms.

Oxytocin (OT) is a pituitary hormone and acts on the oxytocin receptor which are expressed in the brain, heart, kidney and blood vessels. OT has been implicated in its role in social bonding, and oxytocin's role in the parasympathetic nervous system includes the control of memory and learning processes and of various types of behaviour such as feeding, locomotion, as well as maternal and sexual behaviour. Oxytocin is also suggested to participate in the control of cardiovascular functions, thermoregulation, and pain threshold and fluid balance. Inefficient thermoregulation leads to hot flashes, and is associated with memory loss is a common symptom of menopause. Several studies suggest that the use of oxytocin and additional substances that amplify its effects can be used for treating weight changes, mood swings, hot flushes, somatic discomfort, dry and ulcerous mucous membranes, fissures, and bone loss during pre-menopause, menopause itself and post menopause. This review suggests its possible role in gene regulation and physiological function in post menopausal women and the possible mechanisms.

Application of western blotting technique for evaluating the expression of vasopressin receptors in the heart cells; importance in the cardiovascular system.

Vasopressin, a posterior pituitary hormone is responsible for water reabsorption by the kidneys and maintenance of cardio-vascular homeostasis. Vasopressin receptors are characterized as VR 1 (V1a), VR2 (V2), and VR3 (V1b). VR1, which is abundant in vascular smooth muscles, causes vasoconstriction by increasing intracellular calcium via the phosphatidylinositol bisphosphonate pathway and a positive inotropic effect in cardiac muscle. VR2 has also been shown to be expressed in the heart. There is emerging role for vasopressin receptors in health and disease. This study describes the application of Western blotting to elucidate the importance of vasopressin receptors in the heart cells.

Central nervous regulation of spleen function: New insights from animal studies.

The spleen is located in the upper left quadrant of the abdomen. It has two main functions that is acting as part of the immune system and as a filter. The spleen has a thin connective tissue capsule from which short septa extend inwards. These septa are, in turn, connected to a complex reticulin framework.There are two distinct components of the spleen, the red pulp and the white pulp. The red pulp consists of large numbers of sinuses and sinusoids filled with blood and is responsible for the filtration function of the spleen. The splenic venomotor fibres join the left phrenic nerve in the mid-cervical region. Coursing with it as non-medullated fibres, they eventually perforate the diaphragm, where for a time they accompany the inferior phrenic artery. Deviating towards the celiac ganglion, they next join company with the splenic vein, and are eventually distributed to localised parts of the vein. This review article evaluates the conventional knowledge and points to new insights into neural regulation of spleen.

Investigation of seizure activity after cyclic nucleotide phosphodiesterase inhibition with second messenger and calcium ion channel inhibition in mice.

The role of PDE-4 inhibitor etazolate, was evaluated in the presence of PDE-7 inhibitor, BRL-50481, in animal models of epilepsy. Seizures were induced in the animals by subjecting them to injection of chemical convulsants, Pilocarpine, Kainic acid (KA) and maximal electroshock (MES). The combination of etazolate and BRL50481 treated mice showed a significant (P<0.001) quick onset of action, jerky movements and convulsion when compared to gabapentin. The combination of etazolate and sGC inhibitor, methylene blue (MB) treated mice showed a significant (P<0.001) delay in onset of action, jerky movements and convulsion when compare to gabapentin as well as against the combination of etazolate with BRL 50481.The present study mainly highlights the individual effects of etazolate and combination with BRL-50481 potentiates (P<0.001) the onset of seizure activity against all models of convulsion. The study mainly comprises the onset of seizures, mortality/recovery, percentage of prevention of seizures (anticonvulsant) and total duration of convulsive time. The total convulsive time was prolonged significantly (P<0.05 and P<0.01) in combination of methylene blue with etazolate treated (28.59% and 35.15 %) groups, compared to DMSO received group (100%) in the MES model. In the same way, the combination of calcium channel modulator (CCM) and calcium channel blocker (CCB) amiodarone and nifedipine respectively, with etazolate showed a significant (P<0.001) delay in onset of seizures, compared to DMSO and etazolate treated groups in all models of epilepsy. This confirms that both CCM and CCB possess anticonvulsant activity. Finally, the study reveals that identification of new cAMP mediated phosphodiesterases family members offers a potential new therapy for epilepsy management in future.

Vasopressin hormone receptor density and gene expression in lithium induced polyuria rats.

Lithium, a drug frequently used for treatment of affective disorders, is known to cause a vasopressin resistant state, leading to polyuria and polydipsia. It has been suggested that lithium interacts with the renal V2-vasopressin receptor and makes the receptor dysfunctional. Detailed studies on the influence of lithium on the AVP receptor, however, have so far been difficult due to the lack of a suitable radioligand with high specific activity and high affinity. In this study, the effect of Lithium carbonate (20mg/kg i.p) on vasopressin receptor binding in the kidney and brain and the effect on mRNA expression was determined. The results of this study suggest that there was significant change in the receptor binding and gene expression in tissues of polyuria rats as compared to the control rats.

Influence of DNA Methylation and Core Binding Factors in Expression of Leukemia Virus in Hemapoietic Stem Cells.

Retroviral vectors based upon the Moloney murine leukemia virus (MLV) have been used due to their high efficiency of stable gene transfer. Core binding factors (CBF) are heterodimeric transcription factors containing a DNA binding Runx 1, Runx 2, or Runx 3 subunit, along with a non DNA binding CBF ẞ subunit. All four subunits are required at one or more stages of hematopoiesis. This review describes the role of Runx1 and CBF ẞ in the initiation of hematopoiesis in the embryo, and in the emergence of hematopoietic stem cells. The core site in the Moloney murine leukemia virus (Moloney MLV) enhancer was previously shown to be an important determinant of the T-cell disease specificity of the virus. Mutation of the core site resulted in a significant shift in disease specificity of the Moloney virus from T-cell leukemia to erythro-leukemia. It has been shown that a protein that binds the core site, one of the core-binding factors is highly expressed in thymus and is essential for hematopoiesis in stem cells. Earlier studies suggest that CBF plays a critical role in mediating pathogenesis of Moloney MLV in vivo. Spontaneous leukemia was not observed either upon CBF expression, consistent with a model in which the increase in HSC and progenitor populations represents a pre-leukemic state, and additional mutations are required for progression to leukemia.

Current status of glycoprotein IIB/IIIA receptor antagonists and evaluation of their molecular modeling.

Abciximab, Eptifibatide and Tirofiban are the three main glycoprotein IIb/IIIa receptor antagonists which have played a vital role in the field of cardiac medicine. They work by blocking the final mechanism of platelet aggregation pathway. These antagonists are widely used in treating acute coronary syndrome, myocardial infarction and during percutaneous coronary intervention (PCI). In this review, we have examined the chemistry, mechanism of action and clinical uses of these glycoprotein IIb/IIIa receptor antagonists. We also tried to study the binding mode of both eptifibatide and tirofiban with the glycoprotein IIb/IIIa receptors using molecular docking software. It appears that blocking the ASP 224 may be the cause for platelet activity inhibition.

A simple technique for estimation of phospholipase d and phospholipase c enzymes in smooth muscle and its cells.

This research article describes two novel and simple techniques for the estimation of phospholipase D and phospholipase C enzymes in aortic smooth muscle and cells cultured from the bovine aorta. The techniques encompass the use of ion exchange chromatography and liquid scintillation spectrophotometry.

Newer insights into renal regulation of water homeostasis.

The regulation of high osmolality is an important driving force for water reabsorption and urinary concentration--the key functions of the kidney for maintaining optimum body fluid volume. New evidence shows that transcription factor tonicity responsive enhancer binding protein (TonEBP) and calcineurin-nuclear factor of activated T cells through cross-talk enhance Aquaporin 2 (AQP2) expression. AQP2 is the predominant vasopressin regulated water channel of the kidney collecting duct and is essential for urinary concentration. The serine/threonine phosphatase calcineurin is an important signaling molecule involved in kidney development and function. One potential target of calcineurin action is the water channel AQP2. The nuclear factor of activated T cells (NFAT) family has recently been expanded by the discovery of a new member, NFAT 5, or Ton EBP. Ton EBP is the only known mammalian transcription factor that regulates gene expression in response to hypertonicity. This review examines the importance of AQP2, calcineurin, NFATc and TonEBP in the renal regulation of water homeostasis.

PAF antagonism modifies neuroprotective action of histone deacetylase and calcineurin phosphatase inhibitors in mice.

To evaluate the hypothesis that platelet activating factor (PAF) antagonism may affect the functional recovery following the nerve injuries and also to evaluate the effect of PAF receptor antagonism on the neuroprotective effect of tacrolimus and sodium valproate, effect of PAF receptor antagonist, WEB2086 was evaluated in animal models of sciatic nerve crush and endothelin-1 induced focal cerebral ischemia. WEB2086, per se, while attenuating spontaneous sensory motor recovery after sciatic nerve crush, enhanced functional recovery after focal cerebral ischemia. WEB2086 also attenuated the neuroprotective effect of tacrolimus and sodium valproate subsequent to peripheral nerve injury, while it significantly improved the neuroprotective action of tacrolimus and sodium valproate following cerebral ischemia reperfusion injury. These results suggest that PAF receptor antagonists alone and in combination with tacrolimus/sodium valproate could be used in the treatment of cerebral ischemia reperfusion injuries however, their use following peripheral nerve injuries could be detrimental.

Renal humoral modulation of skeletal muscle tone in mice: implications for 'the pulmonary-renal cascade'.

The pulmonary-renal cascade may regulate the respiration and skeletal muscle contractility. To evaluate this working hypothetical model, we conducted experiments to ascertain the skeletal muscle tone of the Swiss mice (20-35 g). The animals were evaluated for their skeletal muscle tone via several techniques i.e. inclined plane test, grip strength test and swim test. Groups of mice (n=6) were pre-treated with mefenamic acid (60 mg/kg, i.p), carbenoxolone (100 mg/kg i.p) or vehicle only 15 minutes before the treatment with heparin (500 U/kg, i.v), urokinase (5500 U/kg, i.v) and erythropoietin (150 U/kg, i.v). Heparin potentiated the loss of skeletal muscle tone induced by mefenamic acid and carbenoxolone while urokinase & erythropoietin significantly enhanced the skeletal muscle tone as evaluated by all or one of the tests. Other groups of mice (n=6) were pretreated with mefenamic acid (1 mg i.c.v), carbenoxolone (160 microg i.c.v) or minoxidil (30 microg i.c.v) and the effects of heparin & urokinase and erythropoietin on skeletal muscle tone were evaluated. To study the effects of heparin and urokinase on nerve regeneration, two groups of mice underwent a sham and sciatic nerve crush procedure. The mice treated with urokinase recovered much faster as compared to those treated with heparin or saline. These experimental results suggest that gap junction blockers and potassium channel openers interact with heparin, urokinase and erythropoietin to control the skeletal muscle tone.