The CoPhyLab comet-simulation chamber.

The Comet Physics Laboratory (CoPhyLab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. The project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners, the physics of comets, including the processes inside cometary nuclei, the activity leading to the ejection of dust and gas, and the sub-surface and surface evolution of cometary nuclei when exposed to solar illumination. CoPhyLab will provide essential information on the formation and evolution of comets and insights into the origins of primitive Solar System bodies. To this end, we constructed a new laboratory that hosts several small-scale experiments and a large-scale comet-simulation chamber (L-Chamber). This chamber has been designed and constructed to host ice-dust samples with a diameter of up to 250 mm and a variable height between 100 and 300 mm. The cometary-analog samples will be kept at temperatures below 120 K and pressures around 10-6 mbar to ensure cometary-like conditions. In total, 14 different scientific instruments are attached to the L-Chamber to study the temporal evolution of the physical properties of the sample under different insolation conditions. Due to the implementation of a scale inside the L-Chamber that can measure weight changes of the samples with high precision, the cooling system is mechanically decoupled from the sample holder and cooling of the samples occurs by radiation only. The constructed chamber allows us to conduct uninterrupted experiments at low temperatures and pressures up to several weeks.

Electron spin resonance studies on the inorganic-anion-transport system of the human red blood cell. Binding of a disulfonatostilbene spin label (NDS-TEMPO) and inhibition of anion transport.

The disulfonatostilbene spin label, NDS-TEMPO, was synthesized (purity over 96%) and the binding of the spin label to human red-cell ghosts was studied. NDS-TEMPO is readily absorbed to the membrane surface. Both pretreatment of the ghosts with FDNB and DIDS and the presence of DNDS completely prevent the binding of NDS-TEMPO to red-cell ghosts. Chloride and sulfate competitively inhibit the binding of NDS-TEMPO. Conversely, NDS-TEMPO is a strong, competitive inhibitor of chloride and of sulfate transport. The dissociation constants of NDS-TEMPO from the ESR studies were in the range 1.0-2.0 microM (pH 7.6, 20 degrees C). The inhibition constants of NDS-TEMPO as obtained from the flux experiments were in the range 0.5-2.5 microM (pH 7.3, 25 degrees C). The close accordance of the NDS-TEMPO dissociation constants from the ESR studies with the NDS-TEMPO inhibition constants from the flux measurements indicate a specific labeling of the inorganic-anion-transport system.

High dose titration of calcium channel blocking agents for primary pulmonary hypertension: guidelines for short-term drug testing.

Forty-seven patients with primary pulmonary hypertension were evaluated with a dose titration protocol utilizing nifedipine (20 mg orally) or diltiazem (60 mg orally) given every hour until maximal effectiveness was achieved. Of the patients tested, 15 (32%) had a greater than 20% reduction in pulmonary artery pressure (mean 36.2 +/- 8%, p less than 0.01) and pulmonary vascular resistance (mean 50.2 +/- 7%, p less than 0.01) (pressure responders). Nineteen (40%) had a greater than 20% reduction in pulmonary vascular resistance (mean 25.2 +/- 12%, p less than 0.01), with less than a 20% decrease in pulmonary artery pressure (resistance responders). Ten had no significant change in pulmonary artery pressure or pulmonary vascular resistance (nonresponders), and three were unable to tolerate the calcium channel blocking agents. No hemodynamic profile allowed prediction of the type of response to these agents. No mortality or serious morbidity was associated with the drug testing. These findings indicate that calcium channel blockers, when titrated to maximally effective doses, may cause substantial reductions in pulmonary artery pressure and pulmonary vascular resistance in patients with primary pulmonary hypertension. Testing with hemodynamic monitoring is necessary to ascertain which patients will respond. Patients with primary pulmonary hypertension are able to tolerate short-term administration of high doses of calcium channel blockers.

Effects of adenosine in combination with calcium channel blockers in patients with primary pulmonary hypertension.

OBJECTIVES: The purpose of this study was to evaluate the effects of vasodilator combination therapy in patients with primary pulmonary hypertension. BACKGROUND: Calcium channel blockers and adenosine have each been shown to be effective in reducing pulmonary artery pressure and pulmonary vascular resistance in patients with primary pulmonary hypertension. However, the effects of combining these vasodilators have not been studied. METHODS: To test the combination, 12 patients were placed on oral nifedipine and 3 on diltiazem therapy, using a dose titrated to maximal effect (mean nifedipine dose 103 +/- 24 mg, mean diltiazem dose 300 +/- 49 mg). Patients were then given maintenance doses of the calcium channel blocker at half the cumulative loading dose at 6-h intervals. One hour after the maintenance dose of calcium blocker, all patients received an infusion of adenosine, starting with 50 micrograms/kg per min and increasing by 50 micrograms/kg per min at 2-min intervals to a maximally tolerated dose (180 +/- 63 micrograms/kg per min). RESULTS: Ten patients responded to calcium channel blockers (defined as a > or = 20% decrease in pulmonary vascular resistance), with a 16% decrease in mean pulmonary artery pressure (p = 0.057), a 39% decrease in pulmonary vascular resistance (p = 0.002) and a 24% increase in stroke volume (p = 0.007). Five patients were nonresponders, with no significant changes in pulmonary artery pressure, pulmonary vascular resistance, cardiac index or stroke volume. In the calcium channel blocker responders, the combination of adenosine and calcium blocker reduced pulmonary vascular resistance by 49%, increased stroke volume by 33% and decreased mean pulmonary artery pressure by 14% compared with drug-free baseline values. In nonresponders, combination therapy resulted in nonsignificant changes in pulmonary artery pressure and pulmonary vascular resistance. CONCLUSIONS: Adenosine has the ability to further decrease pulmonary artery pressure and pulmonary vascular resistance in patients with primary pulmonary hypertension who respond to calcium channel blockers. Those who fail to respond to these agents have little added effect from adenosine.

Neurohormonal activation in patients with right ventricular failure from pulmonary hypertension: relation to hemodynamic variables and endothelin levels.

OBJECTIVES: This study sought to determine whether neurohormonal activation occurs in isolated right heart failure. BACKGROUND: Neurohormonal activation appears to parallel the severity of left heart failure, but little is known about its role in right heart failure. METHODS: We evaluated neurohormonal activation and endothelin levels in 21 patients with primary pulmonary hypertension at the time of right heart catheterization. RESULTS: Plasma norepinephrine levels correlated significantly with pulmonary artery pressure (r = 0.66, p < 0.01), cardiac index (r = -0.56, p < 0.01) and pulmonary vascular resistance (r = 0.69, p < 0.001). Atrial natriuretic peptide levels were higher in the pulmonary artery than the right atrium and femoral artery and correlated closely with pulmonary artery oxygen saturation (r = -0.73, p < 0.0001). Plasma renin levels were not elevated. Endothelin levels were increased and correlated with right atrial pressure (r = 0.74, p < 0.0001) and pulmonary artery oxygen saturation (r = -0.070, p < 0.0004). CONCLUSIONS: Neurohormonal activation occurs in patients with isolated right ventricular failure and inherently normal left ventricles and appears to be related to the overall severity of cardiopulmonary derangements. The elevation in endothelin levels is consistent with its release in response to pulmonary hypertension.

DNA recognition site analysis of Xenopus winged helix proteins.

DNA binding proteins of the winged helix family contain a conserved 110 amino acid region, the fork head/HNF-3 domain. Three members of the recently described XFD (Xenopus fork head domain related) multigene family in the frog Xenopus laevis that contain this DNA-binding domain have been studied. We determined the in vitro DNA recognition sequences by means of two independent methods: PCR supported site selection with degenerated deoxyoligonucleotides and affinity chromatography of genomic Xenopus DNA fragments. In contrast to a remarkable sequence divergence within their protein sequence of the fork head domains, all three proteins share a similar 7 bp DNA target motif. The protein-DNA interaction has been studied by means of DMS interference and hydroxyl radical footprinting. A region of 18 bp encompassing the 7 bp target motif is sufficient to confer binding and specificity. The specificity of binding could be attributed on the DNA level to residues located 5' to the 7 bp core region, and on the protein level most likely to a region within the first half of the fork head domain. The possible role of specific nucleotides within the target site in binding the protein is discussed in the context of the current crystal structure of the complex of this domain with DNA.

Intermediate filament forming ability of desmin derivatives lacking either the amino-terminal 67 or the carboxy-terminal 27 residues.

Amino acid sequence data and results from limited proteolytic digestion have been used to define the three-domain structure of intermediate filament proteins. A centrally located highly alpha-helical domain of about 310 residues well-conserved in sequence principles and length is flanked by the highly variable sequences of the non-alpha-helical headpiece and tailpiece. A direct involvement in filament formation of one or both terminal domains was previously proposed for desmin since chymotryptic removal of head and tailpiece provided a derivative unable to form filaments. In order to evaluate directly the importance of these regions we have prepared desmin derivatives lacking either the amino-terminal 67 (T-desmin) or carboxy-terminal 27 residues (L-desmin). Whereas the latter derivative is fully polymerization-competent the fragment lacking only the basic and arginine-rich headpiece cannot form filaments on its own and remains in a protofilamentous stage. These structures of T-desmin are not incorporated into filaments when mixed with protofilaments of desmin. If, however, the two proteins are mixed in 7 M-urea subsequent dialysis provides morphologically normal filaments containing T-desmin. The results suggest that at least certain hybrid protofilaments containing less than four headpieces are accepted in the filament. The removal of the 27 carboxy-terminal residues in L-desmin, although not interfering with filament formation, leads to a change in surface since filaments show lateral aggregation at 170 mM but not at 50 mM salt. The results are discussed in relation to current models of intermediate filament structure.

Antiparallel orientation of the two double-stranded coiled-coils in the tetrameric protofilament unit of intermediate filaments.

The chymotryptically excised middle domain of desmin slightly exceeds in length the structurally conserved alpha-helical middle region documented in all intermediate filament proteins by amino acid sequence data. This rod domain is a protofilament derivative with a tetrameric organization, thus indicating the presence of two double-stranded coiled-coil units. We now show by immunoelectron microscopy that Fab fragments of a desmin-specific monoclonal antibody mixed with the rod lead to dumb-bell-shaped structures. The tagging of both ends together with the length of the rod (48 nm) argues for an antiparallel orientation of the two coiled-coils without a major stagger. This information combined with the lateral 21 nm periodicity of the intermediate filament observed by us and others leads to a structural hypothesis similar to those entertained from X-ray data on wool alpha-keratins, although here an antiparallel tetrameric unit of some 60 to 66 nm is invoked, which has never been isolated. The structure that we discuss allows for the existence of both the particles, and the antibody experiment strongly supports the antiparallel orientation postulated in both approaches. The tube-like filament structure proposed for the intermediate filament agrees with recent mass per unit length measurements and allows for two minor classes of intermediate filaments with different values in this property as also found experimentally.

Five years on the wings of fork head.

Since its discovery five years ago the conserved family of fork head/HNF-3-related transcription factors has gained increasing importance for the analysis of gene regulatory mechanisms during embryonic development and in differentiated cells. Different members of this family, which is defined by a conserved 110 amino acid residues encompassing DNA binding domain of winged helix structure, serve as regulatory keys in embryogenesis, in tumorigenesis or in the maintenance of differentiated cell states. The purpose of this review is to summarize the accumulating amount of data on structure, expression and function of fork head/HNF-3-related transcription factors.

COMETARY SCIENCE. Thermal and mechanical properties of the near-surface layers of comet 67P/Churyumov-Gerasimenko.

Thermal and mechanical material properties determine comet evolution and even solar system formation because comets are considered remnant volatile-rich planetesimals. Using data from the Multipurpose Sensors for Surface and Sub-Surface Science (MUPUS) instrument package gathered at the Philae landing site Abydos on comet 67P/Churyumov-Gerasimenko, we found the diurnal temperature to vary between 90 and 130 K. The surface emissivity was 0.97, and the local thermal inertia was 85 ± 35 J m(-2) K(-1)s(-1/2). The MUPUS thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength. A sintered near-surface microporous dust-ice layer with a porosity of 30 to 65% is consistent with the data.

SDS-PAGE strongly overestimates the molecular masses of the neurofilament proteins.

Direct molecular mass determination of the three porcine neurofilament proteins (H, M and L) was performed in 6 M guanidine-HCl using analytical gel filtration and sedimentation equilibrium centrifugation. The results show that SDS-PAGE strongly overestimates the values of the 'higher molecular mass' components H and M. This discrepancy stems from the carboxyterminal extensions known to have unusual amino acid composition.

Comparative acute effects of adenosine and prostacyclin in primary pulmonary hypertension.

Vasodilators have been a main focus of therapy for primary pulmonary hypertension. Adenosine and prostacyclin have been shown to reduce pulmonary vascular resistance acutely in these patients. In order to compare the acute hemodynamic effects of adenosine and prostacyclin, ten patients with severe primary pulmonary hypertension, unresponsive to medical therapy, were studied. After baseline hemodynamics were obtained, an adenosine infusion, 50 to 100 ng/kg/min, was begun and titrated to the maximum tolerated dose. Hemodynamics were allowed to return to baseline, and thereafter, a prostacyclin infusion was begun at 2 ng/kg/min, and titrated to the maximum tolerated dose. Overall, adenosine (200 +/- 53 ng/kg/min) produced a 33 +/- 18% (p < 0.001) fall in pulmonary vascular resistance and a 52 +/- 25% (p < 0.001) increase in cardiac output with no effect on pulmonary or systemic arterial pressures. Prostacyclin (8 +/- 4 ng/kg/min) caused a 22 +/- 18% (p < 0.01) fall in pulmonary vascular resistance and a 25 +/- 26% (p < 0.05) increase in cardiac output with a 14 +/- 6% (p < 0.001) decrease in systemic arterial pressure, but no change in pulmonary arterial pressure. The effects of adenosine and prostacyclin on pulmonary vascular resistance were similar (r = 0.70, r2 = 0.49, p = 0.02). Adenosine and prostacyclin have similar hemodynamic effects acutely in primary pulmonary hypertension. Adenosine may be useful as a test of the potential for long-term prostacyclin therapy in patients with primary pulmonary hypertension.

The prevalence and significance of a patent foramen ovale in pulmonary hypertension.

In order to determine the prevalence and significance of a patent foramen ovale (PFO) in pulmonary hypertension, 58 patients were studied with transesophageal echocardiography, right-sided heart catheterization, and exercise testing. In order to examine if a PFO might be associated with a better outcome, survival was estimated, based on a formula derived from the National Institutes of Health Primary Pulmonary Hypertension Registry, for the patients with primary pulmonary hypertension (PPH). A PFO was found in 26 percent (15 of 58) of all patients studied, 25 percent (10 of 40) of those with PPH, and 28 percent (5 of 18) of those with secondary pulmonary hypertension. We found no significant difference in any hemodynamic variable or exercise tolerance between the patients with and without a PFO, or for subsets of patients with primary and secondary pulmonary hypertension. We also found no significant difference in the 1-, 2-, 3-, 4-, or 5-year estimated survival, for the patients with PPH between those with and without a PFO. The prevalence of a PFO in pulmonary hypertension appears similar to the normal population. A PFO provides no detectable influence on resting hemodynamics or exercise tolerance in patients with pulmonary hypertension and is not clearly associated with patients expected to survive longer.

Evaluation of osteoblast response to porous bioactive glass (45S5) substrates by RT-PCR analysis.

Previous studies have shown that neonatal rat calvaria osteoblasts elaborate substantial amounts of extracellular material with bone-like characteristics when cultured on porous bioactive glass substrates in vitro. However, the osteoblastic response to this material has not been fully characterized. The objective of this study was to characterize osteoblast response to porous bioactive glass substrates following the expression of the classical markers for osteoblast differentiation. In this study we synthesized porous bioactive glass substrates, seeded them with osteoblast-like cells (ROS 17/2.8) and followed the temporal expression of alkaline phosphatase (AP) activity, as well as the expression of mRNA for collagen type I (Coll-1), osteonectin (OSN), osteopontin (OPN), osteocalcin (OCN), and bone sialoprotein (BSP). The data confirm that porous bioactive glass substrates are capable of supporting the in vitro growth and maturation of osteoblast-like cells. At a porosity of 42% and an average pore size of 80 microm, the substrates promote the expression and maintenance of the osteoblastic phenotype. The results additionally suggest that there is both a solution-mediated and a surface-controlled effect on cell activity.

Timing of single lung transplantation for primary pulmonary hypertension.

Single lung transplantation has been advocated as a definitive treatment for primary pulmonary hypertension. Because of reports of improved survival in some patients with vasodilators and anticoagulants, the timing of referral for single lung transplantation needs to be examined. Survival in primary pulmonary hypertension was estimated, with the use of a proportional hazards model, from data obtained from the National Institutes of Health registry on primary pulmonary hypertension. Waiting times for single lung transplantation, obtained from the United Network for Organ Sharing, were found to follow an exponential distribution. Under the assumption that waiting time and survival are independent, a model was developed to estimate the probability of surviving to single lung transplantation, depending on the waiting time for a single lung transplantation, and the delay in transplant referral. Examples were computed with hemodynamic data from the National Institutes of Health registry on primary pulmonary hypertension: waiting times of 6, 12, 18, and 24 months and delays in single lung transplantation referral of 0, 1, 2, and 3 years. For a waiting time of 6 months, the chance of surviving to single lung transplantation with a 3-year delay varies from 19% for a patient with a mean pulmonary artery pressure of 80 mm Hg to 72% for a patient with a mean pulmonary artery pressure of 41 mm Hg. For a waiting time of 24 months and a 3-year delay in single lung transplantation referral, this probability varies from 14% (mean pulmonary artery pressure 80 mm Hg) to 59% (mean pulmonary artery pressure 41 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

The advanced glycation end-product N epsilon-(carboxymethyl)lysine level is elevated in cerebrospinal fluid of patients with amyotrophic lateral sclerosis.

Oxidative stress is involved in the aetiopathogenesis of amyotrophic lateral sclerosis (ALS), a fatal degenerative disorder. To test whether oxidative stress in ALS is increased and confined to the central nervous system, we have measured the glycoxidation product N(epsilon)-(carboxymethyl)lysine (CML) in serum and cerebrospinal fluid (CSF) samples by means of a novel enzyme immunoassay. Significant increases of CSF/serum ratio of CML in ALS patients (n = 25) as compared to normal controls (n = 20, p = 0.001) and to Alzheimer disease patients (n = 9, p = 0.029) suggest intrathecal production of this glycoxidation product. Measurement of CML levels may provide a novel diagnostic tool and may supplement current monitoring strategies in interventional trials.

[Has the pH meter replaced the Apgar score?]. / Le pH mètre a-t-il détrôné le score d'Apgar

The introduction of measuring the pH appears to place it in competition with Apgar scoring because of its precision. A study of this which has been carried out has illustrated that there are two different criteria for assessing the state of the infant at birth. The usual agreement between pH values and Apgar scoring can be broken when clinical fetal distress has become established before metabolic equilibrium of the infant has become modified. In these circumstances the Apgar score will be bad while the pH will be good.

[Inhibition of lactation by bromocriptine. 470 cases over a 3-year period]. / Inhibition de la lactation par la bromocriptine. 470 observations recueillies en 3 ans.

Three years of experimental work on 470 cases have given us the opportunity of confirming the usefulness of 2-Bromo-ergocryptine and the excellent way it is tolerated when used for inhibition of lactation. The dosage which is necessary to achieve an approximately 100 p. 100 success rate has been worked out in detail. Pharmacological study has shown that the substance is effective because it inhibits the secretion of prolactin by the pituitary gland.

[Wellness holidays--wholesome wish or one-sided reality]. / Wellness-Ferien--ganzheitlicher Wunschtraum oder einseitige Realität.

The term wellness is widely used in European tourism. The principal observations regarding the wellness industry concern an expanding supply of and an insufficiently researched demand for wellness programs. The quality dimension of wellness services is increasingly becoming the decisive competitive factor. For this reason quality management plays an important role. Market research shows that average 3- to 5-star hotels provide fairly comprehensive wellness facilities. Wellness hotels should therefore specialize in health information, individual care and a wide range of cultural and relaxation programs. Although the same hotel can host cure and wellness guests at the same time, these two segments have to be considered separately when deciding on the marketing strategy. We therefore assume that wellness is pursued solely by 'healthy' people, the prime aim being prevention. 'Normal cure guests' aim to heal their illness.

Detection of ethyl glucuronide in blood spotted on different surfaces.

This study aims to show that sensitive detection of ethyl glucuronide in dried blood spotted onto various surfaces after a period of 24h is feasible. At present, there is insufficient information how tightly ethyl glucuronide (EtG) binds to various materials and how easily it can be eluted. 4ml aliquots of blood samples obtained from seven volunteers after consumption of alcoholic beverages were applied to six different surfaces. After drying and a 24h-storage at 20±2°C the samples were re-dissolved in water, and EtG was subsequently analyzed by a LC-MS Paul-type ion trap. A comparison was made between dried and corresponding fluid samples. EtG was detectable in all subjects' samples following consumption of alcohol. EtG was also detectable after a storage time of four weeks at 4°C in whole blood that had been preserved with EDTA. EtG was detectable in all samples dried on different surfaces and its concentration remained relatively constant irrespective of the particular condition of the material. Detection of EtG in blood spots from the scene may indicate recent alcohol consumption in cases where collection of blood remained undone or could not be performed.