Search results for "erythrocyte"

Staphylococcal alpha-toxin: formation of the heptameric pore is partially cooperative and proceeds through multiple intermediate stages.

1997

Staphylococcal alpha-toxin is a 293 residue polypeptide that assembles into pore-forming heptamers, residues 118-140, thereby inserting to form an amphipathic beta-barrel in the lipid bilayer. Fluorometric analyses were here conducted using cysteine-substitution mutants site-specifically-labeled at positions 35 or 130 with the environmentally-sensitive fluorophore acrylodan. In conjunction with functional assays, three conformational states of the heptamer were defined, which may represent transitional configurations of the toxin molecule along its way to membrane insertion and pore formation. The first was the freshly assembled, SDS-sensitive heptamer alpha7*a, where a minor alteration in …

The hemagglutinin of Staphylococcus saprophyticus is a major adhesin for uroepithelial cells.

1996

The 160-kDa hemagglutinin of Staphylococcus saprophyticus also serves as a fibronectin-binding protein, and the two activities may be present on different parts of the molecule. Bacteria expressing the 160-kDa hemagglutinin bound in large numbers to histological sections of human ureters, whereas nonhemagglutinating bacteria did not bind. Binding was decreased by an antiserum to the 160-kDa protein and by a preparation of sheep erythrocyte membranes. Fibronectin had no effect. We therefore conclude that binding of S. saprophyticus to uroepithelial cells is mediated by the hemagglutinating activity of the 160-kDa surface protein.

Putative identification of an amphipathic alpha-helical sequence in hemolysin of Escherichia coli (HlyA) involved in transmembrane pore formation.

2008

Abstract Escherichia coli hemolysin is a pore-forming protein belonging to the RTX toxin family. Cysteine scanning mutagenesis was performed to characterize the putative pore-forming domain of the molecule. A single cysteine residue was introduced at 48 positions within the sequence spanning residues 170–400 and labeled with the polarity-sensitive dye badan. Spectrofluorimetric analyses indicated that several amino acids in this domain are inserted into the lipid bilayer during pore formation. An amphipathic α-helix spanning residues 272–298 was identified that may line the aqueous pore. The importance of this sequence was highlighted by the introduction of two prolines at positions 284 and…

Erythropoietin mediates tissue protection through an erythropoietin and common beta-subunit heteroreceptor

2004

The cytokine erythropoietin (Epo) is tissue-protective in preclinical models of ischemic, traumatic, toxic, and inflammatory injuries. We have recently characterized Epo derivatives that do not bind to the Epo receptor (EpoR) yet are tissue-protective. For example, carbamylated Epo (CEpo) does not stimulate erythropoiesis, yet it prevents tissue injury in a wide variety ofin vivoandin vitromodels. These observations suggest that another receptor is responsible for the tissue-protective actions of Epo. Notably, prior investigation suggests that EpoR physically interacts with the common β receptor (βcR), the signal-transducing subunit shared by the granulocyte-macrophage colony stimulating fa…

Acanthocytes in urinary sediment--a pathognomonic marker?

1998

Purification, isolation and characterization of a phosphoglycolate phosphatase isoenzyme from human erythrocytes.

1982

1. Preparation, purification and characterization of a phosphoglycolate phosphatase (PGP) isoenzyme from human erythrocytes was achieved by DEAE-Sepharose CL-6B chromatography and isoelectric focusing using carrier ampholytes, pH 4-6. 2. The isoenzyme has an isoelectric point of 5.00 +/- 0.05 and could be purified 33,000 fold to a specific activity of 32.7 U/mg of protein. It represents the PGP phenotype 1 consisting of a single isoenzyme. 3. The enzyme is composed of two subunits (mol. wt 35,000) which are identical and not connected by SS-bridges. 4. At 4 degrees C the isoenzyme is more stable in the pH range of 7-9 than at acid pH values. 5. Incubation at 30 and 40 degrees C for 4 hr doe…

Pyrrolo[2,3-h]quinolinones: A new ring system with potent photoantiproliferative activity

2006

A new class of compounds, the pyrrolo[2,3-h]quinolin-2-ones, nitrogen isosters of the angular furocoumarin Angelicin, was synthesized with the aim of obtaining new photochemotherapeutic agents with increased antiproliferative activity and lower undesired toxic effects than the lead compound. Two synthetic pathways were approached to allow the isolation both of the dihydroderivatives 10-17 and of the aromatic ring system 23. Compounds 10-17 showed a remarkable phototoxicity and a great UVA dose dependence reaching IC(50) values at submicromolar level. Intracellular localization of these compounds has been evaluated by means of fluorescence microscopy using tetramethylrhodamine methyl ester a…

Early Biochemical and Hematological Response to Intramuscular Cyanocobalamin Therapy in Vitamin B<sub>12</sub>-Deficient Patients

2013

<b><i>Background:</i></b> Data on early biochemical and hematological responses to cobalamin therapy in vitamin B<sub>12</sub>-deficient patients are scarce. Therefore, we investigated whether cobalamin injections would include prompt biochemical and hematological responses in vitamin B<sub>12</sub>-deficient patients. <b><i>Subjects and Methods:</i></b> Seven female patients (mean age: 69.4 years, range: 61-78) with a mean serum cobalamin level of 104 ± 38 pmol/l mean ± SD and 7 male patients (mean age: 67.0 years, range: 53-78) with a mean serum cobalamin level of 84 ± 40 (±SD) participated in the study. They were adm…

Reply to "The association of red blood cell distribution width and morbid obesity" by Aydin et al.

2014

We thank Aydin & cols. for their comments about our recently published paper “Red blood cell distribution width is not related with inflammatory parameters in morbidly obese patients” in Clinical Biochemistry Journal [1]. The authors show their concern about the clinical interpretation of our findings since we did not report folate and B12 vitamin levels. Moreover, they state that we should demonstrate the elimination of thrombocytopenic diseases by showing platelet count data. Aswe state in the paper, exclusion criteria for obese patients included “organic, malignant, hematological, infectious or inflammatory disease”. Therefore, any case of thrombocytopenic disease was not included. Moreo…

N-3 fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring.

2006

We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitami…