Acute meningitis caused by Streptococcus constellatus.
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Acute Disease↗
Biomedical subjects
A Romero
Publications and source records attributed to A Romero.
Left ventricular pseudoaneurysm.
Left ventricular (LV) pseudoaneurysms form when cardiac rupture is contained by adherent pericardium or scar tissue. Although LV pseudoaneurysms are not common, the diagnosis is difficult and they are prone to rupture. We evaluated the clinical presentation, diagnostic accuracy of imaging modalities, results of therapy and prognosis of 290 patients with LV pseudoaneurysms. Most cases of LV pseudoaneurysm were related to myocardial infarction (particularly inferior wall myocardial infarction) and cardiac surgery. Congestive heart failure, chest pain and dyspnea were the most frequently reported symptoms, but >10% of patients were asymptomatic. Physical examination revealed a murmur in 70% of patients. Almost all patients had electrocardiographic abnormalities, but these were usually nonspecific ST segment changes; only 20% of patients had ST segment elevation. Although radiographic findings were also usually nonspecific, the appearance of a mass was present in more than one half of patients and may be an important clue to the correct diagnosis. Left ventricular angiography was the most definitive test and can be useful in planning surgery since concomitant coronary angiography can be performed. Regardless of treatment, patients with LV pseudoaneurysms had a high mortality rate, especially those who did not undergo surgery. Because the symptoms, signs, electrocardiographic abnormalities and radiographic findings seen in patients with LV pseudoaneurysms can be indistinguishable from those in patients with coronary disease alone, a high clinical index of suspicion is needed to avoid missing the diagnosis.
Aneurysm, False↗
Cyril Ponnamperuma and the origin of life: a bibliography.
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Biological Evolution↗
Power measurements of spark discharge experiments.
An accurate and precise knowledge of the amount of energy introduced into prebiotic discharge experiments is important to understand the relative roles of different energy sources in the synthesis of organic compounds in the primitive Earth's atmosphere and other planetary atmospheres. Two methods widely used to determine the power of spark discharges were evaluated, namely calorimetric and oscilloscopic, using a chemically inert gas. The power dissipated by the spark in argon at 500 Torr was determined to be 2.4 (+12%/-17%) J s-1 by calorimetry and 5.3 (+/- 15%) J s-1 by the oscilloscope. The difference between the two methods was attributed to (1) an incomplete conversion of the electric energy into heat, and (2) heat loss from the spark channel to the connecting cables through the electrodes. The latter contribution leads to an unwanted effect in the spark channel by lowering the spark product yields as the spark channel cools by mixing with surrounding air and by losing heat to the electrodes. Once the concentrations of the spark products have frozen at the freeze-out temperature, any additional loss of heat from the spark channel to the electrodes has no consequence in product yields. Therefore, neither methods accurately determines the net energy transferred to the system. With a lack of a quantitative knowledge of the amount of heat loss from the spark channel during the interval from ignition of the spark to when the freeze-out temperature is reached, it is recommended to derive the energy yields of the spark products from the mean value of the two methods with the uncertainty being their standard deviation. For the case of argon at 500 Torr, this would be 3.8 (+/-50%) J s-1.
Argon↗
Diagnostic electrocardiography in epidemiological studies of Chagas' disease: multicenter evaluation of a standardized method.
An electrocardiographic recording method with an associated reading guide, designed for epidemiological studies on Chagas' disease, was tested to assess its diagnostic reproducibility. Six cardiologists from five countries each read 100 electrocardiographic (ECG) tracings, including 30 from chronic chagasic patients, then reread them after an interval of 6 months. The readings were blind, with the tracings numbered randomly for the first reading and renumbered randomly for the second reading. The physicians, all experienced in interpreting ECGs from chagasic patients, followed printed instructions for reading the tracings. Reproducibility of the readings was evaluated using the kappa (kappa) index for concordance. The results showed a high degree of interobserver concordance with respect to the diagnosis of normal vs. abnormal tracings (kappa = 0.66; SE 0.02). While the interpretations of some categories of ECG abnormalities were highly reproducible, others, especially those having a low prevalence, showed lower levels of concordance. Intraobserver concordance was uniformly higher than interobserver concordance. The findings of this study justify the use by specialists of the recording of readings method proposed for epidemiological studies on Chagas' disease, but warrant caution in the interpretation of some categories of electrocardiographic alterations.
Argentina↗
Twenty-four-month oral carcinogenicity study of ebrotidine in rats.
Three groups of Sprague-Dawley CD rats (males and females) were initially administered p.o. with ebrotidine, a novel H2-receptor antagonist, mixed with the diet, at 50, 200, and 500 mg/kg/d, respectively. Two concurrent control groups of animals were used. After 13 months, initial 200 mg/kg was lowered to 150 mg/kg, and a new group was administered with 300 mg/kg, due to the body weight reduction observed in the top dose group. After 24 months, survivors were killed and necropsied, and a histopathological study was performed. The frequencies of the different tumour types that were found were not raised due to the treatment. Lower frequencies of some types of pituitary and mammary gland tumours, in the groups treated with the higher doses, were the only statistically significant changes. Among the non-neoplastic effects, a lower body weight increment and food consumption (500 and 300 mg/kg, both sexes), lower survival (500 mg/kg, males), presence of lipoid pneumonia (500 mg/kg, only in males, and 300 mg/kg, both sexes), and lithiasis in urinary system (500 mg/kg) were observed. No changes in gastric mucosa (the main target organ) were attributable to ebrotidine. Regarding the non-neoplastic effects, 150 mg/kg was the no observed adverse effect level. According to the previous results of the carcinogenicity study in mice, conjointly with those of the study in rats reported here, there is no evidence of carcinogenic risk either in males or in females in these species.
Animals↗
[Risk factors of ischemic cardiopathy. Study of patients hospitalized in a coronary unit].
The purpose of this study is to determine the knowledge level patients hospitalized and diagnosed as suffering from ischemic cardiopathia have about their risk factors by means of an observationally, descriptively and cross-sectionally designed study. This study was carried out in the Coronary Care Unit at the Vall d'Hebron General Hospital between December 1995 and March 1996. Data was taken from clinical reports; furthermore, patients involved in the study were interviewed. Among the results obtained, the following are worth special mention: 57 patients or 47.5% knew about a HTA relationship; 97 patients or 81% knew about tobacco as a risk factor; 80 patients or 67% were aware of the cholesterol risk factor; and 58 patients or 48% had information regarding diabetes as a risk factor. No significant statistical differences were found among known coronary patients and nondiagnosed-coronary patients regarding their knowledge of risk factors. Only two-thirds of the study group considered it important to control their risk factors. Given the importance of knowledge about risk factors, perhaps this is the time to consider implementing a health educational program for this segment of the population.
Adult↗
Ligand-binding capabilities, 2.4-A resolution crystal structure, and characterization of oligosaccharides of PSP-I/PSP-II, a porcine heterodimeric lectin of glycosylated spermadhesins.
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Animals↗
Crystal structure of acidic seminal fluid protein (aSFP) at 1.9 A resolution: a bovine polypeptide of the spermadhesin family.
We report the three-dimensional crystal structure of acidic seminal fluid protein (aSFP), a 12.9 kDa polypeptide of the spermadhesin family isolated from bovine seminal plasma, solved by the multiple isomorphous replacement method and refined with data to 1.9 A resolution with a final R-factor of 17.3%. aSFP is built by a single CUB domain architecture, a 100 to 110 amino-acid-residue extracellular module found in 16 functionally diverse proteins. The structure of aSFP reveals that the CUB domain displays a beta-sandwich topology organised into two 5-stranded beta-sheets, each of which contain two parallel and four antiparallel strands. The structure of aSFP is almost identical to that of porcine spermadhesins PSP-I and PSP-II, which in turn show limited structural similarity with jellyroll topologies of certain virus capsid proteins. Essentially, topologically conserved residues in these proteins are those internal amino acids forming the hydrophobic core of the CUB and the jellyroll domains, suggesting their importance in maintaining the integrity of these protein folds. On the other hand, the structure of aSFP shows structural features that are unique to this protein and which may provide a structural ground for understanding the distinct biological properties of different members of the spermadhesin protein family.
Amino Acid Sequence↗
The 2.4 A resolution crystal structure of boar seminal plasma PSP-I/PSP-II: a zona pellucida-binding glycoprotein heterodimer of the spermadhesin family built by a CUB domain architecture.
The crystal structure of porcine seminal plasma spermadhesin PSP-I/PSP-II heterodimer has been determined in two crystal forms by multiple isomorphous replacement in an hexagonal crystal (space group P6(1)22) and molecular replacement in a trigonal crystal of space group P3(2)21. The crystal structure has been refined at 2.4 A resolution to an R-factor of 20.0% (Rfree = 25.9%) for 14,809 independent reflections with intensities greater than 2 sigma (I), with root-mean-square deviations of 0.009 A and 1.657 degrees from ideal bond lengths and bond angles, respectively. The final model includes 1688 non-hydrogen protein atoms of 221 amino acids and 79 water molecules. PSP-I/PSP-II represents the first crystal structure of a mammalian zona pellucida-binding protein. PSP-II displays a putative carbohydrate-recognition site located around its Asn50. This region shares structural features with sugar binding sites of known lectin structures of the leguminous and galectin families. PSP-I and PSP-II are N-glycosylated at asparagine residues 50 and 98, respectively, and show site heterogeneity. Only the innermost N-acetylglucosamine of PSP-I is defined in the crystal structure. Both subunits of the PSP-I/PSP-II heterodimer are built by a single CUB domain architecture. The CUB domain displays a novel fold, which consists of a compact ellipsoidal beta-sandwich structure (42 A x 27 A x 23 A) organized into two 5-stranded beta-sheets. Each sheet contains parallel and antiparallel beta-strands. Two disulphide bridges, which are conserved in all spermadhesin molecules and many CUB domains, crosslink loop LA and strand beta 4 and loops LE and LG, respectively, at opposite edges of the same face of the domain. The four highly conserved aromatic residues and 15 out of 17 invariant hydrophobic residues, which define the CUB domain signature, display an interior location, suggesting that this hydrophobic core may be essential for maintaining the overall folding of the domain. Most of the hydrophobic core residue characteristics are conserved in the jellyroll topology of certain icosahedral virus capsid proteins, indicating that the CUB domain and the viral proteins share a minimal structural core.
Amino Acid Sequence↗
The disulphide bond pattern of bitistatin, a disintegrin isolated from the venom of the viper Bitis arietans.
The disulphide bond pattern of the long disintegrin bitistatin (83 amino acids, 14 cysteines) was established using structural information gathered by amino acid analysis, N-terminal sequencing, and molecular mass determination of fragments isolated by reversed-phase HPLC after polypeptide degradation with trypsin and oxalic acid. A computer program was used to calculate all possible combinations of disulphide-bonded peptides matching the mass spectrometric data, and the output was filtered using compositional and sequence data. Disulphide bonds between cysteines 16-34, 18-29, 28-51, 42-48, 47-72, and 60-79 are conserved in medium-long disintegrins flavoridin and kistrin (70 amino acids, 12 cysteines), and the two cysteine residues at positions 5 and 24 found in bitistatin but not in other disintegrin molecules are disulphide-bridged. This linkage creates an extra, large loop, which, depending on whether the NMR structure of flavoridin or kistrin is used for modelling the structure of bitistatin, lies opposite or nearly parallel, respectively, to the biologically active RGD-containing loop.
Amino Acid Sequence↗
Processing of thionin precursors in barley leaves by a vacuolar proteinase.
Thionins are synthesized as precursors with a signal peptide and a long C-terminal acidic peptide that is post-translationally processed. A fusion protein including the maltose-binding protein from Escherichia coli (MalE), thionin DG3 from barley leaves, and its acidic C-terminal peptide has been used to obtain antibodies that recognize both domains of the precursor. In barley leaf sections, mature thionins accumulated in the vacuolar content, while the acidic peptide was not detected in any cell fraction. Brefeldin A and monensin inhibited processing of the precursor but its export from the microsomal fraction was not inhibited. Both purified vacuoles and an acid (pH 5.5) extract from leaves processed the fusion protein into a MalE-thionin and an acidic peptide fragment. A 70-kDa proteinase that effected this cleavage was purified from the acid extract. Processing of the fusion protein by both lysed vacuoles and the purified proteinase was inhibited by Zn2+ and by Cu2+, but not by inhibitors of the previously described vacuolar processing thiol or aspartic proteinases. In vivo processing of the thionin precursor in leaf sections was also inhibited by Zn2+ and Cu2+. Variants of the fusion protein with altered processing sites that represented those of thionin precursors from different taxa were readily processed by the proteinase, whereas changing the polarity of either the C-terminal or N-terminal residues of the processing site prevented cleavage by the proteinase.
Antimicrobial Cationic Peptides↗
Crystallization and preliminary X-ray diffraction analysis of bovine seminal plasma PDC-109, a protein composed of two fibronectin type II domains.
PDC-109 is a 13 kDa glycoprotein and the major phosphorylcholine- and heparin-binding protein of bull seminal plasma. It is built by an acidic 23-residue N-terminal sequence followed by a tandem of fibronectin type II domains. Full-length PDC-109 was crystallized in complex with o-phosphorylcholine by vapor diffusion in sitting drops. Crystals grew to maximal size of 0.5 x 0.3 x 0.2 mm3, diffract x-rays beyond 2.6 A resolution, and belong to space group P321 with unit cell dimensions a = b = 93.6 A, c = 52.7 A.
Animals↗
Crystallization and preliminary X-ray diffraction studies of aSFP, a bovine seminal plasma protein with a single CUB domain architecture.
Bovine acidic seminal fluid protein (aSFP) is a 1.29 kDa polypeptide of the spermadhesin family built by a single CUB domain architecture. The CUB domain is an extracellular module present in 16 functionally diverse proteins. To determine the three-dimensional structure of aSFP, the protein was crystallized at 21 degrees C by vapor diffusion in hanging drops, using ammonium sulfate, pH 4.7, and polyethyleneglycol 4,000 as precipitants, containing 10% dioxane to avoid the formation of clustered crystals. Elongated prismatic crystals with maximal size of 0.6 x 0.3 x 0.2 mm3 diffract to beyond 1.9 A resolution and belong to space group P2(1)2(1)2(1), with cell parameters a = 52.4 A, b = 41.5 A, c = 48.2 A. There is one aSFP molecule per asymmetric unit, which corresponds to a crystal volume per unit molecular mass of 2.04 A3/Da, and analytical ultracentrifugation analysis show that aSFP is a monomeric protein.
Animals↗
X-ray crystallographic analysis of boar PSP-I/PSP-II complex. A zona pellucida-binding protein.
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Animals↗
Amplification and cloning of a long RNA virus genome using immunocapture-long RT-PCR.
A rapid and easy method was developed in order to amplify long fragments of the genome of potato virus Y (PVY), a virus possessing a 10-kb genomic RNA. The method of immunocapture-RT-PCR was adapted, by using thermostable DNA polymerases with proofreading activity and the proper buffers and cycles, to amplify almost the whole genome of PVY in two fragments (5.6 and 4.3 kb) without purifying virions nor viral RNA. Both fragments were cloned subsequently and their ends sequenced. The method is applicable to the rapid cloning and molecular characterization of the genomes of many other RNA viruses.
Cloning, Molecular↗
Less efficacy with alternating regimen as adjuvant chemotherapy in stage II node-positive breast cancer: results at 8 years (Pronacam 85).
A randomized trial to compare adjuvant treatment with an alternating regimen with conventional chemotherapy was performed. A total of 589 node-positive patients were included and stratified according to number of positive nodes (N1-3 and N > 4) and menopausal status. Premenopausal N1-3 patients were randomized to cyclophosphamide, methotrexate and fluorouracil (CMF) or CMF/4'-epirubicin, cyclophosphamide (EC), post-menopausal N1-3 patients to fluorouracil, 4 epirubicin, cyclophosphamide (FEC) or CMF/EC and pre- and post-menopausal patients with N > or = 4 to fluorouracil, 4' epirubicin, cyclophosphamide, methotrexate, prednisone (FECMP) or CMF/EC. In premenopausal patients, CMF was superior to CMF/EC in terms of disease-free survival (DFS) (65% vs 45%, P = 0.0149) and survival (72.3% vs 50.2%, P = 0.0220) whereas, for N > or = 4 patients, differences between FECMP and CMF/EC did not achieve statistical significance (DFS 35% vs 26.2%; survival 50% vs 38.1%, P = NS). For post-menopausal patients, FEC was superior to CMF/EC in DFS (58.6% vs 36.8%, P = 0.0215) and survival (66.2% vs 46%, P = 0.0155). In post-menopausal patients with N > 4, differences favouring CMF/EC were significant in DFS (40.4% vs 22%, P = 0.0371) but not in survival (47.4% vs 32.2%, P = 0.1185). Alternating regimens did not offer better results in premenopausal and post-menopausal N1-3 patients. Results regarding post-menopausal N > 4 women require further confirmation.
Adult↗
The crystal structures of two spermadhesins reveal the CUB domain fold.
Spermadhesins, 12,000-14,000 M(r) mammalian proteins, include lectins involved in sperm-egg binding and display a single CUB domain architecture. We report the crystal structures of porcine seminal plasma PSP-I/PSP-II, a heterodimer of two glycosylated spermadhesins, and bovine aSFP at 2.4 A and 1.9 A resolution respectively.
Amino Acid Sequence↗