Analysis of anti-U1 RNA antibodies in patients with connective tissue disease. Association with HLA and clinical manifestations of disease

Histatin 1 is a histidine-rich phosphoprotein present in human parotid saliva that possesses candidacidal activity and functions in mineralization by adsorbing to hydroxyapatite. The objective of the present study was to develop a system for recombinant production of histatin 1 and to examine the role of phosphorylation in the functional activities of this molecule. Native histatin 1 (containing a phosphoserine at residue 2) was purified from parotid saliva, whereas a bacterial expression system was used to produce a recombinant form of histatin 1 (re-Hst1) that lacked phosphorylated serine. Histatin 1 cDNA was inserted into the vector pGEX-3X, which expresses foreign genes as soluble fusion proteins attached to the carboxyl-terminus of glutathione S-transferase (GST). The GST/re-Hst1 fusion protein was isolated from cell lysates by affinity chromatography on glutathione (GSH)-Sepharose and digested with cyanogen bromide to separate re-Hst1 from the GST fusion partner. The digest was subjected to reversed-phase high-performance liquid chromatography on a C18 column, and re-Hst1 was eluted as a well-defined peak. The yield of re-Hst1 was 4 mg/L of bacterial culture. Amino-terminal sequencing and amino acid analysis confirmed the final product as re-Hst1. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that native histatin 1 and re-Hst1 had the same apparent molecular weights, while cationic PAGE showed that re-Hst1 was more basic. Phosphate analysis indicated 1 mol phosphate/mol of native histatin 1, while re-Hst1 lacked any detectable phosphate. Re-Hst1 demonstrated candidacidal activity comparable to that of native histatin 1, but displayed substantially lower binding to hydroxyapatite. These results show that phosphorylation of histatin 1 at residue 2 contributes significantly to its ability to bind to hydroxyapatite.     

Salt effects on ligand-DNA binding. Minor groove binding antibiotics

Salt dependent electrostatic effects play a central role in intermolecular interactions involving nucleic acids. In this paper, the finite-difference solution to the nonlinear Poisson-Boltzmann (NLPB) equation is used to evaluate the salt dependent contribution to the electrostatic binding free energy of the minor groove binding antibiotics DAPI, Hoechst 33258 and netropsin to DNA using detailed molecular structures of the complexes. For each of these systems, a treatment based on the NLPB equation accurately describes the variation of the experimentally observed binding constant with bulk salt concentration. A solvation formalism is developed in which salt effects are described in terms of three free energy contributions: the electrostatic ion-molecule interaction free energy, delta delta G degrees im; the electrostatic ion-ion interaction free energy, delta delta G degrees ii; and the entropic ion organization free energy, delta delta G degrees org. The electrostatic terms, delta delta G degrees im and delta delta G degrees ii, have both enthalpic and entropic components, while the term delta delta G degrees org is purely a cratic entropy. Each of these terms depends significantly on salt dependent changes in the counterion and coion concentrations around the DNA. In each of the systems studied, univalent ions substantially destabilize charged ligand-DNA complexes at physiological salt concentrations. This effect involves a salt dependent redistribution of counterions near the DNA. The free energy associated with the redistribution of counterions upon binding is dominated by the unfavorable change in the electrostatic ion-molecule interactions, delta delta G degrees im, rather than the change in the cratic entropy of ion organization, delta delta G degrees org. In addition, the observed slope of the salt dependence of the free energy is determined by electrostatic ion-molecule and ion-ion interactions as well as the cratic entropy of ion release. These findings are in contrast to models in which the cratic entropy of counterion release drives binding.     

Focal hyperexpression of hemeoxygenase-1 protein and messenger RNA in rat brain caused by cellular stress following subarachnoid injections of lysed blood

Induction of the hemeoxygenase-1 (ho-1) stress gene is of importance for rapid heme metabolism and protection against oxidative injury in vitro and in vivo. Although ho-1 expression is observed in glia following exposure to whole blood and oxyhemoglobin, expression is mild, and other stress genes are not induced simultaneously in this setting. Hemeoxygenase-1 can be induced by several other physiological stresses in addition to heme. In the brain, ho-1 induction has been observed in the penumbra following focal cerebral ischemia. Because lysed blood is a spasmogen, the authors studied focal hyperexpression of the ho-1 gene after injection of lysed blood, whole blood, or saline into the cisterna magna of adult rats. Immunocytochemical analysis of HO-1 was performed at 1, 2, 3, and 4 days after the injections. Because the 70-kD inducible heat shock protein (HSP70) is induced by cellular stress, alternate sections were immunostained for HSP70 to assess whether focal hyperexpression was a stress phenomenon. An oligonucleotide probe was also used for in situ hybridization to demonstrate that ho-1 messenger (m)RNA was present. Focal HO-1 immunostained areas were observed after lysed blood injection only and were located mainly in the basal cortex and cerebellar hemisphere, although focal hyperexpression was also found in many other regions. The intensity of staining and the number of regions were maximum at 1 day. Double-labeled immunofluorescence revealed that many HO-1-immunoreactive cells were microglia. The HSP70 immunostaining of adjacent sections from the same animals demonstrated focal regions of immunoreactivity whose topography corresponded exactly with the topography of the HO-1-immunostained areas. Conventional histology in regions of HO-1 hyperexpression was often normal. In situ hybridization using the same oligonucleotide demonstrated that ho-1 mRNA was induced in focal areas of forebrain and in large regions of cerebellum within 6 hours of injection. These results demonstrate that focal hyperexpression of the ho-1 stress gene occurs after lysed blood injection and appears to be an indicator of cellular stress and injury in regions in which infarction does not occur. These results also suggest that cellular injury that occurs after injection of lysed blood may go undetected using conventional histology. Although direct heme metabolism was not investigated, our results indicate that rapid metabolism of heme, both intracellular and extracellular, may prove to be beneficial after subarachnoid hemorrhage.     

Dilutional and modified ultrafiltration reduces pulmonary hypertension after operations for congenital heart disease: a prospective randomized study

OBJECTIVE: A prospective randomized study was performed to test whether removal of endothelin-1, by ultrafiltration techniques, will reduce pulmonary hypertension after operations for congenital heart disease. METHODS: Twenty-four patients with pulmonary hypertension (systolic pulmonary/systemic arterial pressure ratio > 60%) undergoing cardiac operations were randomized into a control group (n = 12) having conventional ultrafiltration and an experimental group (n = 12) undergoing dilutional ultrafiltration during and modified ultrafiltration after cardiopulmonary bypass. Plasma endothelin-1, nitric oxide metabolites, and cyclic guanosine monophosphate were assayed before bypass, 10 minutes into bypass, after bypass, and 0, 3, 6, and 12 hours after the operation in both groups, as well as in the ultrafiltrates and after modified ultrafiltration in the experimental group. Both groups received alpha-blockers (chlorpromazine and/or prazosin) postoperatively using the same guidelines. RESULTS: The ultrafiltrates contained significant amounts of endothelin-1 (1.81 +/- 0.86 pg/ml, dilutional, and 6.44 +/- 1.82 pg/ml, modified ultrafiltrate). Endothelin-1 and the pulmonary/systemic pressure ratio were significantly lower in experimental compared with control patients. Nitric oxide metabolites and cyclic guanosine monophosphate increased similarly in both groups for 12 hours after the operation (p = not significant). Three of 12 control patients (25%) but no experimental patients had pulmonary hypertensive crises (p = 0.07). The experimental patients required significantly less ventilatory support (67 +/- 47 hours vs 178 +/- 139 hours for control patients, p = 0.048). CONCLUSIONS: Dilutional and modified ultrafiltration reduce endothelin-1 and the pulmonary/systemic pressure ratio postoperatively and may become an important adjunct for preventing pulmonary hypertension after operations for congenital heart disease in high-risk patients.     

Factors relating to urinary protein excretion in children with autosomal dominant polycystic kidney disease

Adults with autosomal dominant polycystic kidney disease (ADPKD) who have overt proteinuria (>300 mg/d) have higher mean arterial pressures, lower creatinine clearances, larger renal volumes, and a more aggressive course of renal disease than ADPKD patients without proteinuria. This study examines the relationship between proteinuria and microalbuminuria and similar factors in ADPKD children. A total of 189 children from 81 ADPKD families was included in the analysis. The ADPKD children (n = 103) had significantly greater urine protein excretion rates than the non-ADPKD children (n = 86) (3.9+/-0.3 versus 2.8+/-0.2 mg/m2 per h, P < 0.001). Children with severe renal cystic disease (> 10 cysts; n = 54) had greater protein excretion than those with moderate disease (< or = 10 cysts; n = 49) (4.4+/-0.5 versus 3.3+/-0.2 mg/m2 per h, P < 0.05). The ADPKD children had significantly greater albumin excretion rates than the non-ADPKD children (32+/-6 versus 10+/-2 mg/m2 per 24 h, P < 0.001), and a higher percentage of ADPKD children had significant microalbuminuria (>15 mg/m2 per 24 h in boys and >23 mg/m2 per 24 h in girls) than their unaffected siblings (30% versus 10%, P < 0.05). Thirty percent of ADPKD children had albuminuria and 23% had overt proteinuria. For all ADPKD children, there was no correlation between proteinuria and hypertension. However, there was a significant correlation between urinary protein excretion and diastolic BP among children diagnosed after the first year of life (r = 0.23, P < 0.05). Therefore, proteinuria and albuminuria occur early in the course of ADPKD and may be markers of more severe renal disease.     

Regional cooperation in telecommunications: two examples fromAfrica

An example of cooperation among telecommunications entities in different developing countries is examined. Two multicountry projects in sub-Saharan Africa are discussed in the framework of the International Telecommunication Union's recent recommendations for concerted actions at the regional level. The problems that the least developed countries encounter in carrying out what in the industrialized world might be considered straightforward tasks are highlighted. The examples also illustrate the difficulty of reconciling individual institutional objectives and practices and the practical limits of regional cooperation     

Process safety management of a fuel gas conditioning facility using fault tree analysis

This paper discusses a process hazard management study of a fuel gas conditioning facility based on stateof-the-art fault tree analysis techniques. This facility lowers the water and hydrocarbon dewpoints of a high pressure fuel gas exposed to frigid temperatures during distribution. Using hazards checklists and guidelines as well as internal reviews, various process hazards were identified for this facility. Computerized fault tree analysis techniques were used to identify the failure sequences which could lead to process hazards, and analysts used these results to evaluate the impact of specific hazards upon process safety. Through recommendations presented in the study, the facility owner gained an increased awareness of potential problems and made modifications to reduce the possibility of a hazardous condition and subsequent catastrophic failure.     

Glucose activates both K(ATP) channel-dependent and K(ATP) channel-independent signaling pathways in human islets

We investigated the effects of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) on intracellular Ca2+ concentration ([Ca2+]i) and cell length in isolated and field-stimulated rat cardiomyocytes. [Ca2+]i and cell length of field-stimulated cells were determined simultaneously by confocal laser scan microscopy by using the fluorescent Ca2+ dye Fluo-3. PAF (10(-12)-10(-8) M) inhibited systolic [Ca2+]i increase in a time- and concentration-dependent manner. Maximal effects were observed after an incubation time of 6-8 min, resulting in a 17% (10(-12) M), 41% (10(-10) M), and 52% (10(-8) M PAF) inhibition of systolic [Ca2+]i increase. A time- and concentration-dependent decrease in simultaneously measured cell shortening also was demonstrated. Cell shortening was inhibited by 10% (10(-12) M), 32% (10(-10) M), and 50% (10(-8) M) after an incubation time of 8 min. The effects of PAF could be antagonized by the PAF-receptor antagonist WEB 2170. These data demonstrate that PAF receptor-dependently induces a negative inotropic effect, which is correlated with a decrease in systolic [Ca2+]i and is most likely not due to a decrease in myofilament sensitivity.     

The double-edged sword of rewards for participation in psychology experiments.

This quasi-experimental study examined participation rates and sample characteristics of participants recruited with and without the offer of course credit. In Sample 1, where course credit is not usually offered, credit was added in one condition (N = 195) and not in the other (N = 175). In Sample 2, where credit is usually offered, it was maintained in one condition (N = 92) and removed in the other (N = 178). Results in both samples revealed that participation rates were higher in the credit conditions; they plunged when customary rewards were taken away. Results also revealed evidence of sample bias. More specifically, the motivational characteristics of participants and nonparticipants differed in all conditions except the new credit condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)