Lipids and carotid plaque in the Northern Manhattan Study (NOMAS)

Background

Heterogeneity in B-type natriuretic peptide (BNP) levels, especially among individuals with acute heart failure with normal left ventricular ejection fraction (HFNEF), can cause confusion in interpreting results. We investigated the characteristics of cases of acute HFNEF with only modestly elevated BNP.

Methods

One hundred forty-two patients with acute or acute exacerbation of chronic HFNEF were divided into two groups by BNP level: BNP < 100 pg/ml (NB group, n = 45) and BNP ≥ 100 pg/ml (B group, n = 97). We compared clinical findings, echocardiography results, and neurohormonal factors between these two groups.

Results

In the NB group, a history of open-heart surgery (OHS) was more frequent (71% vs. 22%, p < 0.0001) and hypertension was less frequent (p = 0.0005). Left atrial diameter (LAd) was higher (p = 0.0026), while interventricular septal thickness, posterior wall thickness, relative wall thickness, left ventricular mass index were lower (p = 0.0005, p = 0.0225, p = 0.0114, p = 0.0051, respectively) in the NB group. In patients with HFNEF, a history of OHS remained an independent predictor of BNP level (< 100 pg/ml) after adjustment for hypertension, age, LAd, and interventricular septal thickness (odds ratio 3.6, p = 0.0252).

Conclusion

We found associations between acute HFNEF with less elevated BNP and a history of OHS. In a patient suspected of HFNEF, a history of OHS is considered diagnostic evidence of presence of diastolic heart failure when plasma levels of BNP are less elevated.     

Interactions of ribosomal protein L1 with ribosomal and messenger RNAs

Crystal structures of unbound protein L1 and of its complexes with ribosomal an messenger RNAs are analyzed. It is shown that the values of the apparent association rate constant for L1-RNA depend on conformation of unbound protein L1. It is suggested that L1 binds to rRNA with higher affinity than to mRNA because of additional interactions between domain II of L1 and the loop rRNA region, which is absent in mRNA.     

The internal cavities of pike alpha-parvalbumin probably contain water

The kinetics of hydrogen exchange of pike a-parvalbumin was investigated using the method of infrared spectroscopy (sensitive to the amide hydrogen atoms in the peptide) and radioisotope method (sensitive to all labile hydrogen atoms). Ultraslow exchangeable hydrogen atoms were found to be substantially less in the first case than in the second one. Taking into account that the internal cavities in the parvalbumin are formed by hydrophobic amino acid residues, devoid of labile hydrogen atoms, it is possible to make the most appropriate assumption, namely, these cavities contain water molecules, hydrogen atoms of which are ultraslow exchangeable.     

Hydration of the compact and extended forms of pFh fragments from IgG3 Kuc and Sur

It has been shown using scanning microcalorimetry and densitometry that partial specific heat and specific partial volume of two pFh fragments of IgG3 increase during the decay of its tertiary structure, the secondary structure, the double poly-L-proline helix, being unchanged. This effect may be explained by a high degree of hydration, which increases on globule decompactization due to increased accessibility of peptide groups of the helix to solvent.     

The unusual thermodynamic properties of compact forms pFh fragments (hinge region) IgG3 Kuc and Sur

pFh fragments from the hinge region of human IgG3 Kuc and Sur can fold into compact form, resulting the formation of proteins with secondary (super-secondary) structure, which is represented almost exclusively double poly-L-proline helix. It was demonstrated by several methods that the thermal denaturation of compact form pFh fragment (hinge region) IgG3 Kuc and Sur occurs in two stages. The "two-state" model described the disintegration of the compact structure with preservation of the secondary structure (double poly-L-proline helix). In the second stage melts itself helix consisting of four cooperative units, which are formed by the sections with a high content of proline residues. Poliproline conformation of secondary structure and large number of disulfide bonds is responsible for high specific enthalpy of denaturation and high thermal stability.     

Extraction of the 3D Plasmon Field

We present the novel approach to investigate properties of the 3D plasmon excited on a metal sphere. The exact plasmon field extracted from the scattered field given by Mie theory allows for a new interpretation of the 3D plasmon by four short-range-like plasmons excited and rotating simultaneously around the sphere.     

Complexing of bovine serum albumin with phosphatidyl choline liposomes

Thermodynamic parameters of the bovine serum albumin interaction with phosphatidyl choline liposomes have been determined. It is shown that the bovine serum albumin is adsorbed on the liposomal surface without change of the globule conformation, the polar interactions making dominant contribution in immobilization. The complexing is characterized by a binding constant and a great number of binding sites.     

Limited proteolysis of prolactin in secretory granules from the pituitary gland of estrogenized rats

The LTH-converting proteolytic activity in LTH granules isolated from estrogenized rat hypophysis was studied. Suspensions of granules were incubated at different values of pH for 4 hours at 37 degrees C. The reaction was controlled by SDS electrophoresis. Intensive proteolysis of LTH was observed at pH 6.0 and 3.9, which was accompanied by the formation of fragments with Mr 10, 12 and 17 kD and probably of smaller peptides. An inhibitory analysis revealed that the formation of the 17 kD fragment at pH 3.9 was partly and selectively inhibited by chloroquine, phenanthroline and phenylmethylsulfonyl fluoride. Pepstatin A fully inhibited the proteolysis, whereas leupeptin had no inhibiting influence. The data obtained testify to the presence in the granular fraction of the endopeptidase LTH-converting activity which is sensitive to pepstatin A, an aspartyl proteinase inhibitor as well as to chelators and a serine proteinase inhibitor.     

An Experimental Tool to Estimate the Probability of a Nucleotide Presence in the Crystal Structures of the Nucleotide–Protein Complexes

A correlation between the ligand–protein affinity and the identification of the ligand in the experimental electron density maps obtained by X-ray crystallography has been tested for a number of RNA-binding proteins. Bacterial translation regulators ProQ, TRAP, Rop, and Hfq together with their archaeal homologues SmAP have been used. The equilibrium dissociation constants for the N-methyl-anthraniloyl-labelled adenosine and guanosine monophosphates titrated by the proteins have been determined by the fluorescent anisotropy measurements. The estimated stability of the nucleotide–protein complexes has been matched with a presence of the nucleotides in the structures of the proposed nucleotide–protein complexes. It has been shown that the ribonucleotides can be definitely identified in the experimental electron density maps at equilibrium dissociation constant <10 μM. At K_D of 20–40 μM, long incubation of the protein crystals in the nucleotide solution is required to obtain the structures of the complexes. The complexes with K_D value higher than 50 μM are not stable enough to survive in crystallization conditions.