Measurement of the α-Particle Monopole Transition Form Factor Challenges Theory: A Low-Energy Puzzle for Nuclear Forces?

We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to the 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in a broad Q^{2} range (from 0.5 to 5.0 fm^{-2}). The precision of the new data dramatically supersedes that of older sets of data, each covering only a portion of the Q^{2} range. The new data allow the determination of two coefficients in a low-momentum expansion, leading to a new puzzle. By confronting experiment to state-of-the-art theoretical calculations, we observe that modern nuclear forces, including those derived within chiral effective field theory that are well tested on a variety of observables, fail to reproduce the excitation of the α particle.

First principles description of the giant dipole resonance in 16O.

We present a calculation of the giant dipole resonance in (16)O based on a nucleon-nucleon (NN) interaction from chiral effective field theory that reproduces NN scattering data with high accuracy. By merging the Lorentz integral transform and the coupled-cluster methods, we extend the previous theoretical limits for breakup observables in light nuclei with mass numbers (A ≤ 7) and address the collective giant dipole resonance of (16)O. We successfully benchmark the new approach against virtually exact results from the hyperspherical harmonics method in (4)He. Our results for (16)O reproduce the position and the total strength (bremsstrahlung sum rule) of the dipole response very well. When compared to the cross section from photoabsorption experiments, the theoretical curve exhibits a smeared form of the peak. The tail region between 40 and 100 MeV is reproduced within uncertainties.

Analysis of living cells grown on different titanium surfaces by time-lapse confocal microscopy.

In this study we have combined fluorescence- and reflection-confocal laser scanning microscopy for the simultaneous visualization of living cells and surface topography beneath them. To this purpose we have designed a specific flow chamber and we have tested it with osteoblasts grown on an opaque, thick support, made of smooth or sandblasted titanium. Cells were loaded with Calcein-AM or tetramethylrhodamine methyl ester (TMRM), two probes employed as indicators of cell viability/morphology and mitochondrial membrane potential, respectively. Besides the acquisition of stacks of confocal sections, the system allowed also vertical views and faithful three-dimensional reconstruction of the samples. Confocal microscope implemented with our flow chamber proved to be a promising tool for time-lapse investigation of cell-biomaterial interactions.

Cytoskeletal reorganization in skeletal muscle differentiation: from cell morphology to gene expression.

Actin cytoskeleton profoundly influence a variety of signaling events, including those related to cell growth, survival and differentiation. Recent evidence have provided insights into the mechanisms underlying the ability of cytoskeleton to regulate signal transduction cascades involved in muscle development. This review will deal with the most recent aspects of this field paying particular attention to the role played by actin dynamics in the induction of skeletal muscle-specific genes.

A possible role for polyamines in cartilage in the mechanism of calcification.

The role of polyamines in cartilage is not known: they may be somehow related to the mechanism of calcification. In epiphyseal cartilage from calf scapulas, they are more concentrated in the ossifying area, where calcification takes place, than in the resting region. Spermidine is present in greater amounts than spermine and putrescine. Since ornithine decarboxylase (EC 4.1.1.17) is measurable only in the resting region of the tissue, it is in this area that polyamine biosynthesis occurs, while they accumulate in the ossifying area. Immunohistochemical evidence is obtained that only in the ossifying zone is spermidine extracellular. It is at this level that the matrix is rearranged to become calcified, and proteoglycans are dissociated and partially removed. The effect of polyamines on solutions of proteoglycan subunits has been studied in vitro by following variations of turbidity and viscosity. While in the presence of putrescine the specific viscosity decreases to asymptotic values, in the presence of either 30 mM spermidine or 2.5-10 mM spermine, the decrement is more marked. At the same concentrations, increase of the turbidity of proteoglycan subunit solutions was observed. Only spermidine showed the capacity of displacing proteoglycan subunits from a column of Sepharose 4B-type II collagen: at 15 mM concentration, about 90% of proteoglycans were removed from the column. Alkaline phosphatase activity, which plays an important role in calcification, is enhanced by spermidine and spermine. These results obtained in vitro support the hypothesis that polyamines may be related to calcification of preosseous cartilage.

Dietary sodium change in primary aldosteronism. Atrial natriuretic factor, hormonal, and vascular responses.

Atrial natriuretic factor (ANF) may be physiopathologically involved in several clinical conditions including human hypertension. However, few data are available regarding this putative hormone and its relationship to aldosterone, blood pressure, and vascular responsiveness to alpha-adrenergic receptor stimulation in primary aldosteronism, a volume-expanded, low-renin model of human hypertension. For this reason, the behavior of supine and upright plasma ANF as related to aldosterone, blood pressure, and forearm alpha-adrenergic sensitivity (plethysmographic technique) to intra-arterial norepinephrine infusion was studied in eight patients with primary aldosteronism (five with adenomas, three with hyperplasia) before and at the end of two sequential 1-week low (20 mmol/day) and high sodium (200 mmol/day) diet periods. Basal, predict ANF concentrations decreased and increased after low and high sodium intakes, respectively. Furthermore, highly significant postural ANF decrements after 1 hour of standing occurred with each diet, although they were lower after the low than after the high sodium diet. Plasma aldosterone, either supine or upright, was insensitive to dietary sodium manipulations, suggesting the absence of ANF-mediated control of aldosterone secretion in our patients. In spite of about twofold higher ANF concentrations during the high than during the low sodium diet, forearm vascular sensitivity to intra-arterial norepinephrine infusion did not change during the study. Furthermore, systemic arterial blood pressure rose to a highly significant extent after dietary sodium content was increased, thus casting doubt on a role for ANF as an endogenous long-term modulator of systemic blood pressure and peripheral alpha-adrenergic sensitivity in patients with primary aldosteronism.

Use of Fourier shape descriptors to improve the reproducibility of echographic measurements of arterial intima-media thickness.

BACKGROUND: A major source of error in the longitudinal assessment of the intima-media thickness (IMT) is the difficulty in retrieving the same echographic view of the vessel. OBJECTIVE: To present a method for increasing the reproducibility of IMT measurements by ultrasound in large arteries. METHOD: The Fourier descriptor is a well-known means of describing an object's shape. By means of the discrete Fourier transform (DFT), the shape was represented in a frequency domain; the computational advantages of the DFT then permitted a measure of unlikeness between different shapes (the 'distance' measure; DM) to be defined and used as a criterion for reproducing the contour. When the sonographer compared successive images of a complex vascular segment, like the carotid bifurcation, the identity of the echographic cut was deduced from the identity of the vessel's contour. The best match of the baseline image was the view that minimized the contour DM. RESULTS: Preliminary studies in the carotid artery bifurcations of eight subjects showed that the DM responds to systematic variations in the ultrasound interrogation angle and reveals minimal changes in transducer position. Duplicate scans of 12 subjects were performed by three sonographers with different strategies for acquisition of the same images: a low DM was associated with a low difference in pairs of IMT measurements. Data were classified into two groups (normal or borderline vessels with a pooled mean IMT of 0.62 mm and overtly thickened segments with a pooled mean IMT of 1.31 mm). When minimization of the DM was the criterion for the acquisition of replicate scans, the mean absolute difference of paired data for the mean IMT of the distal common carotid artery was 0.03 +/- 0.02 mm for the first group and 0.06 +/- 0.03 mm for the second group. This is a significant reduction in comparison with non-quantitative alternative criteria for image reproduction. For the maximum IMT of the same segments the mean absolute differences were 0.07 +/- 0.03 and 0.13 +/- 0.06 mm in the first and second groups, respectively. CONCLUSION: This method can be applied to the serial assessment of single atherosclerotic segments. The computational time is negligible. By reducing the scatter in sequential IMT data, longitudinal investigations (e.g. of the results of antihypertensive therapy) with shorter durations and smaller sample groups may be rendered feasible.

Comparison of annexin V and calcein-AM as early vital markers of apoptosis in adherent cells by confocal laser microscopy.

Although morphological criteria for apoptosis are in general reliable, no systematic comparison of the techniques employed thus far has yet been performed. In this study, using confocal laser microscopy, we compared the performance of annexin V-FITC and calcein-AM for early detection of apoptosis in living adherent cells. Experiments were carried out on two distinct cell lines, PC 12 and NIH3T3, endowed with different shape and adhesion properties. The apoptotic process was followed for a prolonged period in the same cells of a predetermined field by means of a special flow chamber. Our results show that both probes allowed the detection of apoptotic cells in either cell line. However, some cells that clearly exhibited apoptotic changes on calcein visualization were annexin-negative. In NIH3T3 cells, annexin negativity of apoptotic cells was correlated with the preservation of cell shape and adhesion properties. These findings show that, at least in PC12 and NIH3T3 cells, annexin might be less sensitive than calcein-AM for early apoptosis detection and, for NIH3T3 cells, suggest that phosphatidilserine exposure is in some way linked to changes in cell shape and/or adhesion to culture substrate. (J Histochem Cytochem 46:895-900, 1998)

Effects of reduced preload on diastolic filling in essential hypertensive patients with increased left ventricular mass.

Doppler-derived indices of diastolic filling are widely used in the routine evaluation of essential hypertensives. However, these indices are affected by loading conditions and systolic performance. This study aimed at monitoring the transmitral flow pattern and indices of left ventricular systolic function during acute nonpharmacological isolated reduction of preload in essential hypertensives with left ventricular hypertrophy. Nine essential hypertensive patients with left ventricular hypertrophy and nine age- and sex-matched normotensive controls underwent echocardiographic and Doppler evaluation of both systolic function and diastolic filling indices at baseline and during lower body suction at -40 mm Hg. Lower body suction caused a similar decrease in end-diastolic volume index, stroke volume index, and midwall fractional shortening in the normotensives and hypertensives. Circumferential end-systolic stress was unaffected in both groups. Acceleration time of early diastolic filling and isovolumic relaxation time increased in the normotensives but not in the hypertensives. Deceleration time of early diastolic filling increased in both groups. The ratio of peak velocities during early filling and at atrial contraction decreased in the normotensives, whereas it was unchanged in the hypertensives; this was due to the fact that early filling velocity decreased in both groups, whereas peak velocity at atrial contraction decreased only in the hypertensives. We conclude that Doppler-derived diastolic filling indices are not affected by a reduction of preload in essential hypertensives with left ventricular hypertrophy.

Ethanol increases the paracellular permeability of monolayers of CAPAN-1 pancreatic duct cells.

When grown on permeable supports, pancreatic duct adenocarcinoma CAPAN-1 cells establish very high values of transepithelial resistance (TER). The addition of ethanol produced a dose-related, reversible drop in the TER of these cells, ranging from 15% (with 1% ethanol) to 65% (with 10% ethanol). The ethanol effect was rapid and reversible. The resistance decrease was associated with an increase in monolayer permeability to mannitol. No significant decrease in cell ATP was detected for ethanol concentrations lower than 7%. Confocal vertical sections of calcein-loaded monolayers of CAPAN-1 cells, grown on plasticware, showed a progressive deflation of domes detectable after 5 min of treatment with 2% ethanol. Incubation in an ethanol-free medium caused a progressive dome restoration. Immunocytochemical analysis of ethanol-treated cells indicated that ZO-1 and occludin exhibited clear cut distribution changes while the perijunctional actin pattern was slightly modified. Electron microscopy showed that a discrete intercellular space was detectable between adjacent ethanol-treated cells but not between control cells. These data indicate that ethanol is a tight junction barrier opener in pancreatic duct cells.

Pattern of human blood spermidine and spermine in prematurity.

Blood polyamines have been determined in preterm newborns (24-37 gestation weeks) during the first hours of life and until 20 days after birth. The most elevated polyamine concentrations were found in preterm newborns from the 24th-33rd gestational week. In all preterms, however, polyamine concentrations are higher than in full term newborns. In preterm infants two different patterns of blood polyamines appear in relation to the gestational age: in infants born at 24-34 wk, spermidine reaches the peak at 12 h and spermine shows high concentrations between 12 and 48 h. In infants born at 35-37 wk maximal concentrations of polyamines were reached at 12 h. Successively, in both groups the polyamines progressively decrease up to the 20th day, with some individual variations. Our results may provide a further support to the suggestion of a fetal genesis of polyamines and their involvement in fetal growth.

Intracellular free [Ca2+] in circulating lymphocytes of spontaneously hypertensive rats.

In the light of previous reports suggesting a common abnormality of Ca handling in most tissues of hypertensive humans and rats, we applied a novel technique using the fluorescent probe Quin 2 for measurement of cytosolic free Ca2+ in lymphocytes of spontaneously hypertensive rats (SHR). (Ca2+)i is increased in SHR (122.1 +/- 7.4 nM) versus normotensive Wistar-Kyoto (WKY) control rats (81.1 +/- 6.3 nM) Membrane exchange, as challenged by varying the extracellular Ca concentration over a 10(5)-fold range proved to be relatively unimportant in regulating (Ca2+)i and did not significantly affect the difference between SHR and WKY. Catecholamines and ouabain had no appreciable effect on (Ca2+)i. The mechanisms of increased (Ca2+)i in SHR lymphocytes remain to be fully elucidated.

EuCliD (European Clinical Database): a database comparing different realities.

Quality and variability of dialysis practice are generally gaining more and more importance. Fresenius Medical Care (FMC), as provider of dialysis, has the duty to continuously monitor and guarantee the quality of care delivered to patients treated in its European dialysis units. Accordingly, a new clinical database called EuCliD has been developed. It is a multilingual and fully codified database, using as far as possible international standard coding tables. EuCliD collects and handles sensitive medical patient data, fully assuring confidentiality. The Infrastructure: a Domino server is installed in each country connected to EuCliD. All the centres belonging to a country are connected via modem to the country server. All the Domino Servers are connected via Wide Area Network to the Head Quarter Server in Bad Homburg (Germany). Inside each country server only anonymous data related to that particular country are available. The only place where all the anonymous data are available is the Head Quarter Server. The data collection is strongly supported in each country by "key-persons" with solid relationships to their respective national dialysis units. The quality of the data in EuCliD is ensured at different levels. At the end of January 2001, more than 11,000 patients treated in 135 centres located in 7 countries are already included in the system. FMC has put the patient care at the centre of its activities for many years and now is able to provide transparency to the community (Authorities, Nephrologists, Patients.....) thus demonstrating the quality of the service.

CagA-positive Helicobacter pylori infection may increase the risk of food allergy development.

The aim of this study was to test whether patients with symptomatic food allergy and significant levels of immunoglobulin E (IgE) to alimentary antigens were more likely infected by H. pylori, especially by strains expressing the CagA protein, with respect to controls. A group of 38 patients with symptomatic food allergy and 53 age-matched controls were examined serologically for H. pylori infectious status, and for CagA seropositivity. IgE to alimentary allergens were measured by a commercial kit. The prevalence of H. pylori infection in patients with food allergy and controls was similar (42.1%, and 48.3%, respectively). However, anti-CagA antibodies in H. pylori-infected persons were detected in 62.5% of patients with food allergy, and 28% of controls (P = 0.030, odds ratio = 4.29). The mean level of IgE to the most common alimentary antigens in serum samples from infected patients with anti-CagA antibodies was significantly higher than in CagA-negative infected patients: 3.28 kU/L (SD 3.93), vs. 1.99 kU/L (SD 1.53), P = 0.002, 95% confidence interval = 0.61 to 2.53). Infection by CagA-positive H. pylori increases the risk of developing food allergy.

The infection by Helicobacter pylori strains expressing CagA is highly prevalent in women with autoimmune thyroid disorders.

UNLABELLED: H. pylori infection is putatively associated with extra-digestive disorders and may also play a role in the development of autoimmune thyroid diseases (ATD). It was recently found that monoclonal antibodies to an H. pylori strain with cagA-positivity reacted with follicular cells of the thyroid gland, and that an H. pylori organism possessing the cag pathogenicity island carried a gene encoding for an endogenous peroxidase. The aims of this study was (1); To ascertain whether the infection by strains endowed with an increased inflammatory potential (those expressing CagA) could further enhance the risk of developing ATD (2); To verify the possible existence of an immune cross-reactivity between autoantibodies to peroxidase and thyroglobulin and H. pylori antigens (3). To establish whether thyroid colloid antigens could cross-react with an anti-H. pylori serum. The study was partly designed retrospectively. We examined 41 consecutive women with ATD, and, as a control, 33 consecutive age- and socio-economic class-matched women without autoimmune thyroid disorders, living in the same area as patients, occurred at the same institution in the same period (six months). Both patients and controls were examined serologically for H. pylori infection and CagA status by Western blotting. Some serum samples were absorbed with H. pylori to determine whether the antibody levels decreased. Colloid proteins were resolved electrophoretically and matched with a hyperimmune serum raised in rabbits against a CagA-positive H. pylori. Thirty-two patients (78.0%) tested seropositive for H. pylori infection, vs. 16 controls (48.4%) (P = 0.008, OR = 3.78, RR = 1.61). The prevalence of anti-CagA antibodies was 71.8% in infected patients, and 50% in infected controls (P = 0.161, n.s.). The overall prevalence of infection by CagA-positive H. pylori was significantly higher in patients with ATD (23/41, or 56.0%) than that in controls (8/33, or 24.2%) (P = 0.006, OR = 3.99, RR = 2.31). The other tests gave negative or inexplicable results. IN CONCLUSION: CagA-positive H. pylori infection increases the risk of ATD development.

An in vitro model for the assessment of manganese neurotoxicity.

PC12 (undifferentiated and differentiated) and C6 cells have been used to investigate kinetics, morphological and functional endpoints following exposure to MnCl(2) and manganic transferrin (Mn-Tf). [Mn](i) in undifferentiated (non-differentiated cells) exposed to both free (MnCl(2)) and bound Mn (Mn-Tf), was three- to fivefold lower as compared to differentiated (differentiated) PC12 cells and higher by one order of magnitude as compared to glial C6 cells. Exposure to both MnCl(2) and Mn-Tf was followed by time- and dose-dependent morphological changes characteristic of apoptosis, which was never observed in Mn-exposed C6 glial cells. Results from cell viability assays were consistent with apoptotic response rates quantified by cell count. Threshold concentrations for undifferentiated and differentiated PC12 cells were 10(-6) and 10(-5)m, respectively. Thus, despite their greater ability to accumulate Mn, differentiated PC12 cells are less sensitive to Mn-induced apoptosis. This model might be relevant to neuronal degeneration induced by Mn occurring in the developing brain and possibly in clinical manganism. Such critical doses at the cellular level seem to be consistent with Mn levels (5x10(-6)m) recorded in the basal ganglia of monkeys chronically exposed to Mn and developing clinical signs of manganism.

Changes of polyamine concentrations in infants during the first six months of life.

Polyamines were detected in the blood of infants during the first six months of life. The highest spermidine levels were found at the 2nd and the 4th month after birth. Spermine, on the contrary, does not show significant differences. Different types of diet produced no changes in the polyamine pattern.

Histochemical detection of sugar residues in chick embryo developing lingual glands with horseradish-peroxidase conjugated lectins.

Tongue anlage were taken in chick embryos from the 7th to the 21st d of incubation and in 3 d old chicken. A battery of 7 different horseradish peroxidase-conjugated lectins (PNA, ConA, DBA, SBA, LTA, WGA, UEA I) was used to study the carbohydrate residues of glycoconjugates at the epithelial cells of the anterior and posterior lingual glands. Some sugar residues, detected at the surface of the epithelial cells in early developmental stages of glandular primordia, seemed to play a role in inducing and regulating the first differentiative steps of the glands. Differences in type, amount, time of appearance and cellular localization between the 2 groups of glands were detected. The group of the anterior lingual glands, adjacent to the entoglossal cartilage (paraentoglossal glands), showed some peculiar histochemical characteristics.

EuCliD--a medical registry.

OBJECTIVES: The European Clinical Database EuCliD small star, filled has been developed as a tool for supervising selected quality indicators of about 200 European dialysis centers. Major efforts had to be made to comply with local and European laws regarding data security. METHOD: EuCliD is a Lotus Notes based flat-file database currently containing medical data of more than 14,000 dialysis patients from 10 European countries. Another 15,000 patients from 150 centers in 4 South-American countries will be added soon. Data are entered either manually or by means of interfaces to existing local data managing systems. This information is transferred to a central Lotus Notes Server. Data evaluation was performed with statistical tools like SPSS. RESULTS: EuCliD is used as a part of the CQI (Continuous Quality Improvement) management system of Fresenius Medical Care (FMC) dialysis units. Each participating dialysis center receives (currently every half year) benchmarking reports at a regular interval. The benchmark for all quality parameters is the weighted mean of the corresponding data of all centers. CONCLUSIONS: An obvious impact of data sampling and data evaluation on the quality of the treatments could be observed within the first one and a half years of working with EuCliD. This also concerns important outcome predictors like Kt/V and hemoglobin concentration as the outcome itself expressed in hospitalization days and survival rates. With the help of EuCliD the user is able to sample clinical data, identify problems, search for solutions with the aim of improving the dialysis treatment quality and guarantee a high-class treatment quality for all patients.

Fluorescent in situ hybridisation on tissue sections: a quantitative approach with confocal laser scanning microscopy.

The use of fluorescent detection methods in association with digital microscopy technologies is an innovative approach for tissue localisation of messenger RNA. The success of such methods relies on the tissue preservation, local availability of the probe and on the existence of high resolution tridimensional analysis systems. Cryostatic sections, mild denaturation, short oligonucleotide probes (20mer) and confocal laser scanning microscopy allow the fulfillment of all these conditions avoiding photobleaching and tissue autofluorescence. In this paper, we describe in detail a method for in situ hybridisation set up with digoxigenin-coupled oligonucleotide complementary to beta-actin mRNA as a probe and an anti-hapten fluorescent antibody as second step for detecting specific hybridisation. Fluorescence was analysed by means of a confocal laser scanning microscope (CLSM) that provides images with low out-of-focus blurring also with relatively low numerical aperture (NA) objectives. We propose also an easy method to perform semi-quantitative thresholding analysis which allows to discriminate between background and specific signal.