Arachidonic acid inhibits Na⁺-K⁺-ATPase via cytochrome P-450, lipoxygenase and protein kinase C-dependent pathways in sheep pulmonary artery

The purpose of the study was to examine whether arachidonic acid inhibits vascular Na(+)-K(+)-ATPase in pulmonary vasculature and if so, what are the mechanisms involved. Functional Na(+)-K(+)-ATPase activity was studied in terms of K(+)-induced relaxation in sheep pulmonary arterial rings contracted with K(+)-free solution and 5-HT. Arachidonic acid (10-100 μM) caused concentration-dependent inhibition of KCl-induced relaxations and also increased basal arterial tone. Cytochrome P-450 inhibitor, 17-octadecynoic acid (17-ODYA) completely reversed the arachidonic acid (30 μM)-induced inhibition of KCl relaxation. Further, in the presence of HET0016, a selective blocker of 20-hydroxyeicosatetraenoic acid (20-HETE), arachidonic acid-induced inhibition of KCl relaxation was not evident. Accordingly, 20-HETE, a cytochrome P-450 metabolite of arachidonic acid, also significantly attenuated KCl-induced relaxations. Norhydihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, however, partially restored the relaxation to K(+), impaired in the presence of arachidonic acid (30 μM). On the other hand, cyclooxygenase inhibitor indomethacin failed to reverse the inhibitory effect of arachidonic acid on KCl-induced relaxation. Staurosporin, a protein kinase C inhibitor, completely reversed the inhibitory effect of arachidonic acid and 20-HETE on K(+)-induced relaxation. In conclusion, the results suggest that 20-HETE, a cytochrome P-450 metabolite of arachidonic acid has a predominant role in the inhibition of functional Na(+)-K(+)-ATPase activity in the sheep pulmonary artery, while the lipooxygenase pathway has a secondary role. It is also evident that protein kinase C is involved in the inhibition of Na(+)-K(+)-ATPase by arachidonic acid/20-HETE in sheep pulmonary artery.     

The in vivo behavior and antitumor activity of doxorubicin-loaded poly(γ-benzyl l-glutamate)-block-hyaluronan polymersomes in Ehrlich ascites tumor-bearing BalB/c mice

The in vivo efficacy of doxorubicin (DOX)-loaded poly(γ-benzyl l-glutamate)-block-hyaluronan (PBLG(23)-b-HYA(10))-based polymersomes (PolyDOX) was evaluated. Samples were efficiently labeled with technetium-99m radionuclide with good stability for in vivo studies. PolyDOX enhanced circulation time compared to free DOX. Biodistribution studies revealed selective accumulation of PolyDOX in the Ehrlich ascites tumor (EAT) as a result of passive accumulation and active targeting (CD44-mediated endocytosis) in EAT-bearing mice. Toxicity studies demonstrated PolyDOX is a safe drug carrier, and no hemolysis was observed with PolyDOX equivalent to 200 μg/mL of free DOX. PolyDOX dominantly controlled tumor growth by delaying doubling time of EATs compared to free DOX over 30 days after treatment. PolyDOX also increased life span six times more than free DOX. Hence, it is reasonable to expect that higher DOX levels attributable to PolyDOX improve the therapeutic index and reduce side effects due to site-specific drug accumulation. FROM THE CLINICAL EDITOR: In this preclinical project, doxorubicin loaded polymersomes enhanced intracellular uptake of doxorubicin in a murine model of Ehrlich Ascites Tumor (EAT) through CD44 receptor mediated endocytosis, resulting in prolonged Tumor Doubling Time and increase in life span of mice.     

Detection of urinary antigens and their seroreactivity with serum of patients in Leishmania donovani infection

ObjectiveTo detect leishmanial antigens in pre and post treated urine of visceral leishmaniasis (VL) patients.MethodsUrine and serum sample from three VL patients were collected. Ammonium sulphate precipitation and purification of urine sample was done for proteins isolation. SDS PAGE of proteins was done followed by western blotting, with the patient's pre and post treatment serum.ResultsEight proteins of molecular weights 17 kDa, 25 kDa, 28 kDa, 42 kDa, 47 kDa, 54 kDa, 60 kDa and 85 kDa were detected in the urine of VL patients before treatment. After treatment with miltefosine, none of the above proteins was detected in urine samples. The western blot analysis with pre treatment serum confirmed the antigenicity of four urinary proteins of molecular weights 25 kDa, 28 kDa, 54 kDa and 60 kDa. The seropositivity with 25 kDa and 28 kDa antigens was negative with serum obtained after the completion of treatment.ConclusionsIn the context to unavailability of a prognostic tool, urinary leishmanial antigens may offer a better choice and may also be useful as immunoprophylactic candidates.     

Synergy of microRNA and stem cell: a novel therapeutic approach for diabetes mellitus and cardiovascular diseases

MicroRNAs ( miRNAs) are highly conserved, 19-23 nucleotide long, non-coding, endogenous RNA, which are transcribed from either intergenic, intronic or polycistronic regions and modulate gene expression through mRNA degradation or translational repression. They are fine tuners of biological processes and have recently emerged as biomarkers and therapeutic targets of cardiovascular diseases. Several miRNAs regulate stem cell for differentiation, proliferation and degeneration. Stem cells are pluripotent, self-renewing and clonogenic cells having tremendous potential for regenerative therapy. The current therapeutic approach is unable to cope up with rapidly increasing rates of diabetes and cardiovascular diseases. The empirical and clinical evidences revealed that transplantation of exogenous stem cells can regenerate beta cells in diabetic patients and myocardium in patients with myocardial infarction. Nevertheless, the major limitation of stem cell therapy is unpredictable behavior of exogenous stem cells that incur few reports of teratoma and cancer after transplantation. Therefore, understanding the regulation of newly transplanted stem cells into the foreign body is a major challenge to translational research / clinical trail. Since miRNA plays pivotal role in the fine regulation of proliferation and differentiation of stem cells, investigations on the regulation of miRNA in transplanted stem cells in a specific micro-environment that houses the stem cell is indispensable. Additionally, the inhibition or over expression of specific miRNAs in the niche surrounding the stem cell will be crucial for maintaining the specific lineage of exogenous stem cells. This review embodies major advancement in the field of miRNA biogenesis and its regulatory mechanisms, role of different miRNAs and stem cells as a therapeutic target for diabetes and cardiovascular diseases. It also provides insights into the novel future therapy, where synergistic approach for manipulating miRNAs and stem cells will emerged as a potential treatment for diabetes and cardiovascular diseases.     

Isolated nocturnal auditory hallucinations: a case report

Sleep-related hallucinations (hypnagogic and hypnopompic) are transient and occur in normal individuals. Rarely, they are prominent and distressing and are associated with diverse conditions including narcolepsy. We report a case of prominent hypnopompic auditory hallucinations — which gradually became continuous and distressing with characteristics of schizophrenia-like hallucinations — that responded to a low dose of olanzapine.     

Antipsychotic sensitivity in normal pressure hydrocephalus

Normal pressure hydrocephalus is characterized by a clinically progressive triad of an abnormal gait, dementia and urinary incontinence, which might present as paranoid psychosis, mood disorder, obsessive-compulsive disorder and, occasionally, with frontal lobe symptoms. We are reporting a patient having schizophrenia with intolerance to even low dose of antipsychotics, who was subsequently revealed to be having communicating hydrocephalus.     

Curcumin prevents haloperidol-induced development of abnormal oro-facial movements: possible implications of Bcl-XL in its mechanism of action

Curcumin (Curcuma Longa Linn), the active component of turmeric, has been shown to be effective in ameliorating several stress and drug-induced disorders in rats and humans. However, it is unclear whether short term curcumin administration can prevent the abnormal oro-facial movements (AOFM) which develop following blockade of dopamine D2 receptors by antagonist such as Haloperidol. The objective of this study is to determine whether short term treatment with curcumin along with Haloperidol can prevent the development of AOFM in rats. Male Sprague Dawley rats were administered curcumin at 200 mg/kg, and Haloperidol at 2 mg/kg daily for 2 weeks, and AOFMs and locomotor activity were assessed at baseline, day 7 and day 14. By day 14, rats receiving concurrent curcumin administration had a significant reduction in the incidence of Haloperidol-induced AOFMs, but no change on the Haloperidol-induced hypolocomotion. There was no spiked increase in locomotor activity in absence of challenge with dopamine D2 receptor agonist. The exact mechanism by which curcumin attenuates AOFMs remains unknown, therefore, we performed a proteomic analysis of the striatal samples obtained from control and curcumin treated groups. A number of proteins were altered by curcumin, among them an antiapoptotic protein, Bcl-XL, was significantly upregulated. These results suggest that curcumin may be a promising treatment to prevent the development of AOFMs and further suggest some therapeutic value in the treatment of movement disorders.