Friday, May 29, 2009

What's new for 'Trypanosomatids' in PubMed

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Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results
Items 1 -7 of 7

1: Indian J Pediatr. 2009 May 27. [Epub ahead of print]Click here to read

Unusual presentations of visceral leishmaniasis.

Prasad R, Muthusami S, Pandey N, Tilak V, Shukla J, Mishra OP.

Department of Pediatrics, Banaras Hindu University, Varanasi, India, rajnitip@gmail.com.

We report 3 cases of Visceral leishmaniasis, who presented with unusual clinical manifestations. One child was diagnosed as hemophagocytic syndrome; another masqueraded with features of leukemoid changes alongwith hemophagocytosis and trilineage myelodysplasia; the third case presented with pyothorax. All the three patients showed amastigote forms of Leishmania donovani and positive serology (rk39 antigen). They showed complete clinical, hematological and parasitological resolution with Amphotericin B therapy.

PMID: 19475352 [PubMed - as supplied by publisher]

2: J Clin Pathol. 2009 Jun;62(6):574-5.Click here to read

Greater abundance of extracellular Leishmania donovani bodies: possible clue from comparison of bone marrow aspirate and imprint findings.

Chopra A, Anand M, Kalita D, Singh S, Kumar R.

Laboratory Oncology Unit, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India.

PMID: 19474363 [PubMed - in process]

3: Clin Nephrol. 2009 May;Volume 71(May):492-500.

Renal tubular dysfunction in human visceral leishmaniasis (Kala-azar).

Agenor Araújo Lima Verde F, Araújo Lima Verde F, De Francesco Daher E, Martins Dos Santos G, Saboia Neto A, Mendoça Lima Verde E.

1Nephrology Institute of Ceará (INECE), 2Resident of Nephrology, Federal University of Rio Grande do Sul, Brazil, 3Department of Internal Medicine, School of Medicine, Federal University of Ceará, Fortaleza, 4Resident of Nephrology, Department of Internal Medicine, School of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil, and 5Medical Student at Christus University, Fortaleza, Brazil.

Background: There are few studies about the functional tubular disturbances in human Kala-azar. The aim of this study was to investigate alterations in tubular reabsorption of urinary proteins, sodium, potassium, chloride, glucose, uric acid, inorganic phosphate and amino acids in patients with the chronic form of kala-azar. Patients and methods: This is a cross-sectional study of 55 patients with visceral leishmaniasis (Kala-azar). The laboratorial investigation was: creatinine clearance and daily urinary excretion of total proteins, albumin, IgG, beta2-microglobulin, sodium, potassium, chloride, calcium, inorganic phosphate, uric acid and glucose. Plasma and urinary protein electrophoresis were performed in agarose gel. Urinary light chains were determined by the nephelometric method and amino acids by chromatography. All data were compared to those of a control group. Results: Hypoalbuminemia, hypergammaglobulinemia as well as increased plasma levels of both IgG and beta2-microglobulins were found in all patients with Kala-azar. The mean urinary protein excretion was 277 +/- 66 mg/day. Increased albumin excretion was observed in 44% of patients accounting for 17% of the total urinary protein excretion. Proteinuria consisted predominantly of low molecular weight protein fractions that migrated with alpha1, alpha2, beta and especially gamma globulins. Urinary beta2-microglobulin excretion was elevated in all patients. Immune electrophoresis showed increased urinary excretion rates of kappa (27%) and lampda (42%) light chains. The Bence-Jones test was positive in 20% of patients. Immunofixation was negative for monoclonal peak. The principal alterations were hyponatremia 94.6%, hypokalemia 26%, hypochloremia 27.2%, hypocalcemia 32%, hypomagnesemia 41.8%, hypouricemia 14.3%, Increased urinary excretion fraction were: sodium 15%, potassium 26%, chloride 33.3%, calcium 32%, inorganic phosphate 27.2%, magnesium 100% with hypermagnesiuria, uric acid 44%. Glucosuria was found in one third of patients. Conclusion: There was evidence of renal proximal tubular damage with alterations in the reabsorption of proteins and light chains with characteristics of a tubular proteinuria, Disturbances of tubular reabsorption of uric acid, calcium, phosphate, glucose and magnesium were also observed.

PMID: 19473608 [PubMed - as supplied by publisher]

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4: PMC Biophys. 2009 May 27;2(1):4. [Epub ahead of print]Click here to read

Three-dimensional studies of pathogenic peptides from the c-terminal of Trypanosoma cruzi ribosomal P proteins and their interaction with a monoclonal antibody structural model.

Martin OA, Villegas ME, Aguilar CF.

ABSTRACT: The acidic C-terminal peptides from Trypanosoma cruzi ribosomal P proteins are the major target of the antibody response in patients suffering Chagas's chronic heart disease. It has been proposed that the disease is triggered by the cross-reaction of these antibodies with the second extra cellular loop of the beta1-adrenoreceptor, brought about by the molecular mimicry between the acidic C-terminal peptides and the receptor's loop. To improve the understanding of the structural basis of the autoimmune response against heart receptors, the 3-dimensional structure of the C-terminal peptides of Trypanosoma cruzi ribosomal proteins P0 (EDDDDDFGMGALF) and P2beta (EEEDDDMGFGLFD) were solved using the Electrostaticaly Driven MonteCarlo method. Their structures were compared with the second extra-cellular loop of our homology model of human rhodopsin and the existing experimental NMR structures of the C-terminal peptides from human P0 (EESDDDMGFGLFD) and from Leishmania braziliensis P0 (EEADDDMGFGLFD). Docking of Trypanosoma cruzi peptides P0, P2beta and human rhodopsin loop into our anti-P2beta monoclonal antibody homology model allowed to explore their interactions. The solution structure of peptides P0 and P2beta can be briefly described as a bend. Although the global conformations of the peptides are not identical they shared a common region of four residues (3 to 6) that have a similar structure. The structural alignment of the five peptides also showed a surprising conformational similarity for the same residues. The antibody model and docking studies revealed a most remarkable feature in the active site, a positively charged, narrow and deep cavity where the acidic residues 3 to 6 were accommodated. These results suggest that the most important elements in the molecular peptide recognition by the antibody may be the shape of the loop and the presence of negative charges in positions 3-5 (P0, P2beta) or a negative charge in position 4 (rhodopsin loop). This work describes clearly the interactions of the structural elements involved in the autoimmune mechanism of anti-P auto-antibodies cross-reaction and stimulation of the beta1-adrenoreceptor and the visual pigment rhodopsin. Results from this study could lead eventually to the development of treatments to abolish receptor mediated symptoms in Chagas. PACS code: 87.15.-v.

PMID: 19473527 [PubMed - as supplied by publisher]

5: Am J Trop Med Hyg. 2009 May;80(5):782-7.Click here to read LinkOut

Role of NO synthase in the development of Trypanosoma cruzi-induced cardiomyopathy in mice.

Durand JL, Mukherjee S, Commodari F, De Souza AP, Zhao D, Machado FS, Tanowitz HB, Jelicks LA.

Department of Physiology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

Trypanosoma cruzi infection results in an increase in myocardial NO and intense inflammation. NO modulates the T. cruzi-induced myocardial inflammatory reaction. NO synthase (NOS)1-, NOS2-, and NOS3-null mice were infected with T. cruzi (Brazil strain). Infected NOS1-null mice had increased parasitemia, mortality, and left ventricular inner diameter (LVID). Chronically infected NOS1- and NOS2-null and wild-type mice (WT) exhibited increased right ventricular internal diameter (RVID), although the fold increase in the NOS2-null mice was smaller. Infected NOS3-null mice exhibited a significant reduction both in LVID and RVID. Reverse transcriptase-polymerase chain reaction showed expression of NOS2 and NOS3 in hearts of infected NOS1-null and WT mice, whereas infected NOS2-null hearts showed little change in expression of other NOS isoforms. Infected NOS3-null hearts showed an increase only in NOS1 expression. These results may indicate different roles for NOS isoforms in T. cruzi-induced cardiomyopathy.

PMID: 19407124 [PubMed - indexed for MEDLINE]

6: Int J Syst Evol Microbiol. 2009 Apr;59(Pt 4):893-909.Click here to read Nucleotide, Taxonomy via GenBank, Protein, PopSet, LinkOut

Selective recovery of the cultivation-prone components from mixed trypanosomatid infections: a case of several novel species isolated from Neotropical Heteroptera.

Yurchenko VY, Lukes J, Jirku M, Maslov DA.

Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA.

Mixed trypanosomatid infections (a simultaneous presence of two or more parasites in the same host) have long been suspected to represent an obstacle for recovering cultures that would faithfully represent original species descriptions. However, without the means to directly compare the parasites in the host and in culture, this would remain just a possibility. Here we have used PCR-based genotyping of spliced leader RNA gene repeats to analyse several novel species of insect trypanosomatids isolated from heteropteran hosts and to compare them with the parasites that had been detected in the gut smears of the same hosts. We have found that, whereas the original infections were dominated by some blastocrithidia-like parasites, most of the respective axenic cultures contained novel species of Crithidia and Leptomonas. Therefore, we concluded that, in each case, this replacement was caused by differences in cultivation properties between the original predominant blastocrithidia and the less fastidious parasite that was later recovered in culture. The properties of the new organisms, including their morphology and ultrastructure, as well as their phylogenetic affinities within the family, were investigated and used to describe five novel species.

PMID: 19329626 [PubMed - indexed for MEDLINE]

7: Biochemistry. 2009 Apr 21;48(15):3398-406.Click here to read LinkOut

Modulation of catalytic function by differential plasticity of the active site: case study of Trypanosoma cruzi trans-sialidase and Trypanosoma rangeli sialidase.

Demir O, Roitberg AE.

Department of Chemistry and Quantum Theory Project, University of Florida, Gainesville, Florida 32611-8435, USA.

trans-Sialidase is an essential enzyme for Trypanosoma cruzi, the causative agent of Chagas' disease, to escape from the host immune system and to invade the host cells. Therefore, T. cruzi trans-sialidase (TcTS) presents a potential and appealing therapeutic target for this lethal disease. The availability of a structurally very similar enzyme with strict hydrolase activity (Trypanosoma rangeli sialidase, TrSA) provides us a unique opportunity to understand the determinants of their structure and catalytic mechanism. In this study, we compare the catalytic cleft plasticity of free (apo) and ligand-bound (holo) forms of the two enzymes using molecular dynamics simulations. We focus on the mouth of the catalytic cleft that is defined by two residues: W312 and Y119 in TcTS and W312 and S119 in TrSA. Our results indicate that TcTS has a very flexible, widely open catalytic cleft, mostly due to W312 loop motion, in apo form. However, when the catalytic cleft is occupied by a ligand, the flexibility and solvent exposure of TcTS is significantly reduced. On the other hand, TrSA maintains a more open catalytic cleft compared to its crystal structures in both apo and holo forms (and compared to TcTS in holo forms). The reduced solvent exposure of TcTS catalytic cleft might be partially or fully responsible for TcTS to be a less efficient hydrolase than TrSA.

PMID: 19216574 [PubMed - indexed for MEDLINE]

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