Polymerase chain reaction detection of Leishmania DNA in skin biopsy samples in Sri Lanka where the causative agent of cutaneous leishmaniasis is Leishmania donovani

Leishmania donovani is the known causative agent of both cutaneous (CL) and visceral leishmaniasis in Sri Lanka. CL is considered to be under-reported partly due to relatively poor sensitivity and specificity of microscopic diagnosis. We compared robustness of three previously described polymerase chain reaction (PCR) based methods to detectLeishmania DNA in 38 punch biopsy samples from patients presented with suspected lesions in 2010. Both, Leishmaniagenus-specific JW11/JW12 KDNA and LITSR/L5.8S internal transcribed spacer (ITS)1 PCR assays detected 92% (35/38) of the samples whereas a KDNA assay specific forL. donovani (LdF/LdR) detected only 71% (27/38) of samples. All positive samples showed a L. donovani banding pattern upon HaeIII ITS1 PCR-restriction fragment length polymorphism analysis. PCR assay specificity was evaluated in samples containing Mycobacterium tuberculosis, Mycobacterium leprae, and human DNA, and there was no cross-amplification in JW11/JW12 and LITSR/L5.8S PCR assays. The LdF/LdR PCR assay did not amplify M. leprae or human DNA although 500 bp and 700 bp bands were observed in M. tuberculosis samples. In conclusion, it was successfully shown in this study that it is possible to diagnose Sri Lankan CL with high accuracy, to genus and species identification, using Leishmania DNA PCR assays.     

Effects of intima stiffness and plaque morphology on peak cap stress

Background  

Rupture of the cap of a vulnerable plaque present in a coronary vessel may cause myocardial infarction and death. Cap rupture occurs when the peak cap stress exceeds the cap strength. The mechanical stress within a cap depends on the plaque morphology and the material characteristics of the plaque components. A parametric study was conducted to assess the effect of intima stiffness and plaque morphology on peak cap stress.     

Acute analgesic effect of loperamide as compared to morphine after intrathecal administration in rat

Loperamide, a mu opioid receptor agonist, which is commonly used as an antidiarrhoeal agent has been reported to possess analgesic activity after intrathecal administration. However, the exact analgesic profile, i.e., onset, duration and intensity of analgesia in relation to morphine is not fully known. In the present study, the acute analgesic effect of loperamide (5 microg) was compared with that of morphine (5 microg) and morphine + loperamide (5 microg of each) using the tail flick method after intrathecal administration. Naloxone (5 mg/kg) reversibility of the analgesic effect was also studied. The analgesic response of loperamide was significantly higher than morphine. Even after 22 hr, maximum possible effect was greater than 49%. Naloxone partially antagonized the analgesic effect of loperamide. This suggested that loperamide may be acting through blockade of Ca2+ channels besides activating mu opioid receptors. Loperamide may prove to be a better substitute for morphine as spinal analgesic.     

A topological model of biofeedback based on catecholamine interactions

Background  

The present paper describes a topological model of biofeedback. This model incorporates input from a sensory organ and a transduction phase mediated through catecholamine production in the feedback path. The transduction phase comprises both conservative and dissipative systems, from which the appropriate output is combined in a closed loop.     

Activation of wild type p53 function by its mortalin-binding, cytoplasmically localizing carboxyl terminus peptides

The Hsp70 family member mortalin (mot-2/mthsp70/GRP75) binds to a carboxyl terminus region of the tumor suppressor protein p53. By in vivo co-immunoprecipitation of mot-2 with p53 and its deletion mutants, we earlier mapped the mot-2-binding site of p53 to its carboxyl terminus 312-352 amino acid residues. In the present study we attempted to disrupt mot-2-p53 interactions by overexpression of short p53 carboxyl-terminal peptides. We report that p53 carboxyl-terminal peptides (amino acid residues 312-390, 312-352, 323-390, and 323-352) localize in the cytoplasm, whereas 312-322, 337-390, 337-352, and 352-390 locate mostly in the nucleus. Most interestingly, the cytoplasmically localizing p53 peptides harboring the residues 323-337 activated the endogenous p53 function by displacing it from p53-mortalin complexes and relocating it to the nucleus. Such activation of p53 function was sufficient to cause growth arrest of human osteosarcoma and breast carcinoma cells.     

Extracellular matrix proteoglycans control the fate of bone marrow stromal cells

Extracellular matrix glycoproteins and proteoglycans bind a variety of growth factors and cytokines thereby regulating matrix assembly as well as bone formation. However, little is known about the mechanisms by which extracellular matrix molecules modulate osteogenic stem cells and bone formation. Using mice deficient in two members of the small leucine-rich proteoglycans, biglycan and decorin, we uncovered a role for these two extracellular matrix proteoglycans in modulating bone formation from bone marrow stromal cells. Our studies showed that the absence of the critical transforming growth factor-beta (TGF-beta)-binding proteoglycans, biglycan and decorin, prevents TGF-beta from proper sequestration within the extracellular matrix. The excess TGF-beta directly binds to its receptors on bone marrow stromal cells and overactivates its signaling transduction pathway. Overall, the predominant effect of the increased TGF-beta signaling in bgn/dcn-deficient bone marrow stromal cells is a "switch in fate" from growth to apoptosis, leading to decreased numbers of osteoprogenitor cells and subsequently reduced bone formation. Thus, biglycan and decorin appear to be essential for maintaining an appropriate number of mature osteoblasts by modulating the proliferation and survival of bone marrow stromal cells. These findings underscore the importance of the micro-environment in controlling the fate of adult stem cells and reveal a novel cellular and molecular basis for the physiological and pathological control of bone mass.     

Angiogenesis and rhodopsin-like receptors: a role for N-terminal acidic residues?

Numerous rhodopsin-like G-protein coupling receptors induce or inhibit angiogenesis. The active human receptors include several chemokine receptors, apelin APJ receptor, neuropeptide Y Y2 receptor, Duffy antigen, and herpes virus-8 receptor. A common and striking feature of these receptors is the large fraction (up to 42%) of residues with anionic sidechains (Asp, Glu, and benzene anions Tyr, Trp, and Phe) in the N-terminal extracellular domain. These residues (which are frequently clustered) can assist the binding of ligand peptides, but should also support interactions that help tubular arraying of cells, e.g., via cationic bridges and/or hydrogen bonding with cell-connecting receptors such as integrins, or with proteins of the extracellular matrix.