Bone strain index reproducibility and soft tissue thickness influence: a dual x-ray photon absorptiometry phantom study.

BACKGROUND: Bone strain index (BSI) is a tool measuring bone strain, derived from dual x-ray photon absorptiometry. It is able to characterise an aspect of bone quality that, joined to the quantity and quality parameters of bone mineral density (BMD) and trabecular bone score (TBS), permits an accurate definition of fracture risk. As no data are available about BSI precision, our aim was to assess its in vitro reproducibility. METHODS: A Hologic spine phantom was used to perform BSI scans with three different scan modes: fast array (FA), array (A), and high definition (HD). Different soft tissue thicknesses (1, 3, 6 cm) of fresh pork rind layers as a surrogate of abdominal fat were interposed. For each scan mode, the phantom was consecutively scanned 25 times without repositioning. RESULTS: In all scan modes (FA, A, HD) and at every fat thickness, BSI reproducibility was lower than that of BMD. The highest reproducibility was found using HD-mode with 1 cm of pork rind and the lowest one using HD-mode with 6 cm of pork rind. Increasing fat thickness, BSI reproducibility tended to decrease. BSI least significant change appeared to be about three times that of BMD in all modalities and fat thicknesses. Without pork rind superimposition and with 1-cm fat layer, BSI reproducibility was highest with HD-mode; with 3 or 6 cm fat thickness, it was higher with A-mode. CONCLUSIONS: BSI reproducibility was worse than that of BMD, but it is less sensitive to fat thickness increase, similarly to TBS.

Assessment of climate change effects on mountain ecosystems through a cross-site analysis in the Alps and Apennines.

Mountain ecosystems are sensitive and reliable indicators of climate change. Long-term studies may be extremely useful in assessing the responses of high-elevation ecosystems to climate change and other anthropogenic drivers from a broad ecological perspective. Mountain research sites within the LTER (Long-Term Ecological Research) network are representative of various types of ecosystems and span a wide bioclimatic and elevational range. Here, we present a synthesis and a review of the main results from ecological studies in mountain ecosystems at 20 LTER sites in Italy, Switzerland and Austria covering in most cases more than two decades of observations. We analyzed a set of key climate parameters, such as temperature and snow cover duration, in relation to vascular plant species composition, plant traits, abundance patterns, pedoclimate, nutrient dynamics in soils and water, phenology and composition of freshwater biota. The overall results highlight the rapid response of mountain ecosystems to climate change, with site-specific characteristics and rates. As temperatures increased, vegetation cover in alpine and subalpine summits increased as well. Years with limited snow cover duration caused an increase in soil temperature and microbial biomass during the growing season. Effects on freshwater ecosystems were also observed, in terms of increases in solutes, decreases in nitrates and changes in plankton phenology and benthos communities. This work highlights the importance of comparing and integrating long-term ecological data collected in different ecosystems for a more comprehensive overview of the ecological effects of climate change. Nevertheless, there is a need for (i) adopting co-located monitoring site networks to improve our ability to obtain sound results from cross-site analysis, (ii) carrying out further studies, in particular short-term analyses with fine spatial and temporal resolutions to improve our understanding of responses to extreme events, and (iii) increasing comparability and standardizing protocols across networks to distinguish local patterns from global patterns.

beta-adducin (Add2) KO mice show synaptic plasticity, motor coordination and behavioral deficits accompanied by changes in the expression and phosphorylation levels of the alpha- and gamma-adducin subunits.

Adducins are a family of proteins found in cytoskeleton junctional complexes, which bind and regulate actin filaments and actin-spectrin complexes. In brain, adducin is expressed at high levels and is identified as a constituent of synaptic structures, such as dendritic spines and growth cones of neurons. Adducin-induced changes in dendritic spines are involved in activity-dependent synaptic plasticity processes associated with learning and memory, but the mechanisms underlying these functions remain to be elucidated. Here, beta-adducin knockout (KO) mice were used to obtain a deeper insight into the role of adducin in these processes. We showed that beta-adducin KO mice showed behavioral, motor coordination and learning deficits together with an altered expression and/or phosphorylation levels of alpha-adducin and gamma-adducin. We found that beta-adducin KO mice exhibited deficits in learning and motor performances associated with an impairment of long-term potentiation (LTP) and long-term depression (LTD) in the hippocampus. These effects were accompanied by a decrease in phosphorylation of adducin, a reduction in alpha-adducin expression levels and upregulation of gamma-adducin in hippocampus, cerebellum and neocortex of mutant mice. In addition, we found that the mRNA encoding beta-adducin is also located in dendrites, where it may participate in the fine modulation of LTP and LTD. These results strongly suggest coordinated expression and phosphorylation of adducin subunits as a key mechanism underlying synaptic plasticity, motor coordination performance and learning behaviors.

Multi Tbit/in(2) storage densities with thermomechanical probes.

Exploiting the spatial resolution of scanning probes presents an attractive approach for novel data storage technologies in particular for large-scale data repositories because of their inherent potential for high storage density. We show that multi-Tbit/in(2) density can be achieved by means of thermomechanically embossing the information as indentation marks into a polymer film. The data density is determined by the nonlinear interaction between closely spaced indents and the fundamental scaling relations governing the shape and size of the indents. We find that cooperative effects in polymers give rise to a minimum indentation radius on the order of the correlation length of the cooperatively rearranged region even if formed by an infinitely sharp indenter. Thus, cooperativity coupled to alpha-transitions in polymers is evinced in a real space geometrical experiment. Furthermore, we predict that indentation marks cannot be made smaller than 5 nm in diameter, which limits the feature resolution for embossing technologies in general.

Heparin induced thrombocytopenia: pathogenetic, clinical, diagnostic and therapeutic aspects.

Heparin induced thrombocytopenia (HIT) in addition to bleeding complications are the most serious and dangerous side effects of heparin treatment. HIT remains the most common antibody-mediated, drug-induced thrombocytopenic disorder and a leading cause of morbidity and mortality. Two types of HIT are described: Type I is a transitory, slight and asymptomatic reduction of platelet count occurring during 1-2 days of therapy. HIT type II, which has an immunologic origin, is characterized by a thrombocytopenia that generally onset after the fifth day of therapy. Despite thrombocytopenia, haemorrhagic complications are very rare and HIT type II is characterized by thromboembolic complications consisting in venous and arterial thrombosis. The aim of this paper is to review new aspects of epidemiology, pathophysiology, clinical features, diagnosis and therapy of HIT type II. There is increasing evidence that platelet factor 4 (PF4) displaced from endothelial cells, heparan sulphate or directly from the platelets, binds to heparin molecule to form an immunogenic complex. The anti-heparin/PF4 IgG immune-complexes activates platelets through binding with the Fcgamma RIIa (CD32) receptor inducing endothelial lesions with thrombocytopenia and thrombosis. Cytokines are generated during this process and inflammation could play an additional role in the pathogenesis of thromboembolic manifestations. The onset of HIT type II is independent from dosage, schedule, and route of administration of heparin. A platelet count must be carried out prior to heparin therapy. Starting from the fourth day, platelet count must be carried out daily or every two days for at least 20 days of any heparin therapy regardless of the route of the drug administration. Patients undergoing orthopaedic or cardiac surgery are at higher risk for HIT type II. The diagnosis of HIT type II should be formulated on basis of clinical criteria and confirmed by in vitro demonstration of heparin-dependent antibodies detected by functional and antigen methods. However, the introduction of sensitive ELISA tests to measure anti-heparin/PF4 antibodies has showed the immuno-conversion in an higher number of patients treated with heparin such as the incidence of anti-heparin/PF4 exceeds the incidence of the disease. If HIT type II is likely, heparin must be immediately discontinued, even in absence of certain diagnosis of HIT type II, and an alternative anticoagulant therapy must be started followed by oral dicumaroids, preferably after resolution of thrombocytopenia. Further studies are required in order to elucidate the pathogenetic mechanism of thrombosis and its relation with inflammation; on the other hand large clinical trials are needed to confirm the best therapeutic strategies for HIT Type II.

Cancer and thromboembolism: from biology to clinics.

The association between cancer and thromboembolic disease is a well-known phenomenon and can contribute significantly to the morbidity and mortality of cancer patients. Recent studies evidenced that malignant growth has also been linked to activity of heparin-like glycosoaminoglycans, to neoangiogenesis, to protease activity, to immune function and gene expression in addition with activation of coagulation and fibrinolysis. These evidences suggest that antithrombotic drugs may play an additional role in tumour cell growth and in cancer dissemination. The spectrum of thromboembolic manifestations in cancer patients includes deep vein thrombosis, pulmonary embolism, but also intravascular disseminated coagulation and abnormalities in the clotting system in the absence of clinical manifestations. Antithrombotic drugs such as unfractioned heparin (UFH) and, particularly, low molecular weight heparins (LMWH) in addition with dicumaroids, are widely used for the prevention and treatment of thromboembolic manifestations that commonly accompanies malignancies. The aims of the study are to review the pathogenetic mechanisms of thromboembolic disease in cancer patients, the efficiency of antithrombotic drugs in preventing and treating of cancer related thromboembolic complications and review the thromboprophylaxis strategies to prevent thromboembolic complications of cancer patients. Meta-analyses comparing UFH and LMWH for the treatment of deep vein thrombosis have shown better outcome with reduction of major bleeding complications in patients treated with LMWH. Many studies have demonstrated the efficiency and the safeness of antithrombotic agents in the prophylaxis and in the treatment of thromboembolic complication that accompanies malignancies. Many experimental studies, reviewed in this paper, support the hypothesis that antithrombotic agents, but especially heparins can affect cancer progression in many of the different steps of cancer biology. First of all, due to their anticoagulant effect, antithrombotic agents may interfere with thrombin generation and with fibrin formation induced by cancer cells, thus inhibiting the mechanism of metastasis.

New antithrombotic agents.

The main clinical indications for anticoagulant agents are treatment and prophylaxis of venous and arterial thromboembolism and acute coronary syndromes. For decades, two anticoagulants, heparin and warfarin, have been the principal drugs available. Dicumaroid agents have serious limitations due to their narrow therapeutic range, needing close monitoring. The interaction with food and drugs and the numerous interindividual variations result in unstable effects on coagulation parameters. On the other side, heparins have an exclusive parenteral use and a risk of immunological adverse reactions. Heparin induced thrombocytopenia is the most serious complication. The limitations of existing oral and parenteral anticoagulant agents have prompted the search for alternative anticoagulant drugs. This paper reviews new anticoagulant agents describing their pharmacological and clinical properties. It focuses on the target of their anticoagulant action inside the coagulation pathway, and analyzes the clinical trials providing indications for new clinical anticoagulation strategies. Agents currently under study include direct thrombin inhibitors, indirect activated factor X inhibitors, and inhibitors of tissue factor and activated factor VII. The new anticoagulant agents may demonstrate improvements in effectiveness, safety convenience and cost-effectiveness compared with current anticoagulants.

Syncope in patients with pulmonary embolism: comparison between patients with syncope as the presenting symptom of pulmonary embolism and patients with pulmonary embolism without syncope.

Syncope as an initial presentation of pulmonary embolism occurs in 10% of patients. We compared clinical and instrumental parameters in patients with syncope as the presenting symptom of pulmonary embolism and in patients with documented pulmonary embolism without syncope. Seventy patients with the diagnosis of pulmonary embolism and apparently stable clinical conditions were evaluated. They were divided in two groups: 10 patients with syncope as the presenting symptom of pulmonary embolism (group 1) and 60 patients without syncope (group 2). Patients with syncope showed a more pronounced tendency to present with main pulmonary artery embolus than patients without syncope (contingency coefficient = 0.301, p < 0.04; one-tailed). However, despite the evidence that patients with syncope have significant reductions in systolic and/or diastolic blood pressure, shock was not observed in any patient. In no case was thrombolytic treatment given and all patients received standard anticoagulation with unfractioned heparin and oral anticoagulant. We suggest that syncope in the setting of non-massive pulmonary embolism may be due to vaso-vagal mechanism that can lead to a reduction of arterial blood pressure when central artery thrombosis is involved.

Hypertension in beta-adducin-deficient mice.

Polymorphic variants of the cytoskeletal protein adducin have been associated with hypertension in humans and rats. However, the direct role of this protein in modulating arterial blood pressure has never been demonstrated. To assess the effect of beta-adducin on blood pressure, a beta-adducin-deficient mouse strain (-/-) was studied and compared with wild-type controls (+/+). Aortic blood pressure was measured in nonanesthetized, freely moving animals with the use of telemetry implants. It is important to note that these mice have at least 98% of C57Bl/6 genetic background, with the only difference from wild-type animals being the beta-adducin mutation. We found statistically significant higher levels of systolic blood pressure (mm Hg) (mean+/-SE values: -/-: 126.94+/-1.14, n=5; +/+: 108.06+/-2. 34, n=6; P:

Mild spherocytic hereditary elliptocytosis and altered levels of alpha- and gamma-adducins in beta-adducin-deficient mice.

The membrane skeleton, a dynamic network of proteins associated with the plasma membrane, determines the shape and mechanical properties of erythrocytes. Deficiencies or defects in membrane skeletal proteins are associated with inherited disorders of erythrocyte morphology and function. Adducin is one of the proteins localized at the spectrin-actin junction of the membrane skeleton. In this work we show that deficiency of beta-adducin produces an 80% decrease of alpha-adducin and a fourfold up-regulation of gamma-adducin in erythrocytes. beta-Adducin or any other isoform generated by translation of abnormally spliced messenger RNAs could not be detected by our antibodies either in ghosts or in cytoplasm of -/- erythrocytes. Actin levels were diminished in mutant mice, suggesting alterations in the actin-spectrin junctional complexes due to the absence of adducin. Elliptocytes, ovalocytes, and occasionally spherocytes were found in the blood film of -/- mice. Hematological values showed an increase in reticulocyte counts and mean corpuscular hemoglobin concentration, decreased mean corpuscular volume and hematocrit, and normal erythrocyte counts that, associated to splenomegaly, indicate that the mice suffer from mild anemia with compensated hemolysis. These modifications are due to a loss of membrane surface and dehydration that result in an increase in the osmotic fragility of red blood cells. The marked alteration in osmotic fragility together with the predominant presence of elliptocytes is reminiscent of the human disorder called spherocytic hereditary elliptocytosis. Our results suggest that the amount of adducin remaining in the mutant animals (presumably alphagamma adducin) could be functional and might account for the mild phenotype. (Blood. 2000;95:3978-3985)

[Meningococcal meningitis in the adult complicated by cutaneous necrosis: description of a clinical case]. / Meningite meningococcica dell'adulto complicata da necrosi cutanea: descrizione di un caso clinico.

Meningitis and meningococcal sepsis are emergency conditions associated with high mortality. The outcome is worsened by the onset of disseminated intravascular coagulation. This may present, particularly in children, with the clinical picture of purpura fulminans, characterized by extensive necrotic-hemorrhagic skin lesions, ischemia of the extremities and multiorgan failure. It has been observed that depletion of coagulation inhibitors, particularly protein C, plays a key role in the development of this severe complication. We describe the case of a woman who presented in the Emergency Room with signs of meningitis, drowsiness, hypotension and petechie. Bacterioscopic examination of the cerebrospinal fluid evidenced characteristic gram-negative diplococci. Laboratory data disclosed initial disseminated intravascular coagulation with low levels of proteins C and S. Following intravenous infusion of antibiotics, fluids and fresh frozen plasma, the patient's condition rapidly improved. However, multiple skin lesions appeared on her fingers, toes and heels. It is likely that the infusion of coagulation inhibitors contained in fresh frozen plasma, prevented evolution to full-blown purpura fulminans. The first choice treatment for purpura fulminans in meningococcal sepsis is infusion of protein C concentrate, which is not, however, currently available on the market.

Expression of RGD minus fibronectin that does not form extracellular matrix fibrils is sufficient to decrease tumor metastasis.

Fibronectin (FN) is a plasma and extracellular matrix (ECM) glycoprotein, the expression of which may modulate the invasive and metastatic abilities of cancer cells. LMM3 is a cell line derived from the highly metastatic mouse mammary adenocarcinoma MM3 and is unable to express FN both at protein and mRNA levels. To study the role of FN in the metastatic process, LMM3 cells were stably transfected with 2 variants (wt and RGD-minus) of a full length human FN cDNA. All analyzed clones secreted recombinant FN and although none assembled FN in the ECM they showed an in vitro reduced migratory ability and an increased adhesive capacity. FN-producing cells were assayed for experimental and spontaneous metastasis. All clones tested showed a significant reduction in the number of experimental lung metastasis when compared with a control clone. Similar trends were observed for spontaneous metastatic ability. Our results indicate that the expression of FN that lacks the well-recognized RGD cell-binding site and that does not form ECM fibrils, is sufficient to decrease the metastatic potential of cancer cells. Our results also suggest that an RGD-independent mechanism may be acting in the prevention of metastasis.

A new epitope presenting system displays a HIV-1 V3 loop sequence and induces neutralizing antibodies.

The principal neutralizing domain, IGPGRAF sequence, from the V3-loop of HIV-1 was inserted in two positions on the surface of the protein that makes up the capside shell of the insect Flock House Virus. The hybrid proteins were expressed in insect cells via recombinant baculoviruses. Three different hybrids were used as immunogens: two with a single copy of the insert in different positions of the carrier protein and a third with two copies of the insert at the same positions as before. All hybrid proteins induced strong and broad specific immune response in guinea pigs against different V3-loop sequences. However, only one of the hybrid proteins was able to induce a strong neutralizing response against MN and IIIB HIV-1 isolates. Our results demonstrate that a very short peptide sequence of HIV-1 can constitute a valuable immunogen able to induce a neutralizing response if presented to the immune system in the context of the FHV capsomer structure.

[Reliability of clinical parameters in the diagnosis of pulmonary thromboembolism at an emergency department]. / Affidabilità dei parametri clinici nella diagnosi di tromboembolia polmonare in Pronto Soccorso.

BACKGROUND: Pulmonary thromboembolism (PTE) mortality rate is four times greater among non-diagnosed than among diagnosed and hence suitably treated patients. Diagnosis, however, may be difficult due to the aspecific and polymorphic clinical picture of the disease. OBJECTIVE: We made a comparison between two groups of patients with PTE. In the first group the diagnosis was immediately suspected, in the second group it was delayed. The aim of our work was to identify any clinical or laboratory feature which may be helpful (singularly or jointly considered) to immediately recognize PTE in the Emergency Department. MATERIALS AND METHODS: 62 patients with PTE were studied retrospectively in 5 consecutive years. They came to E.D. because of symptoms and signs of cardiorespiratory failure. Pulmonary embolism was demonstrated in 60 cases by high probability pulmonary scan; in 2 cases (who suddenly died after the first visit) by autopsy. They were divided in two groups according to the first provisional diagnosis made after the first visit: group A (n 33 = 53.2%) with assumed pulmonary embolism; group B (n 29 = 46.8%) with other diagnosis. History, clinical findings, ECG, chest X-ray, blood gas analysis and routine laboratory tests were then compared between group A and group B patients. RESULTS: No differences were observed between diagnosed and non-diagnosed patients, except for a significantly higher rate of clinically overt deep venous thrombosis in group A. Three main clinical pictures were detected among our patients: 1-circulatory collapse syndrome: n = 20 (32.3%), of whom 8 in group A and 12 in group B (p = n.s.); 2-pulmonary infarction syndrome: n = 12 (19.4%), of whom 5 in group A and 7 in group B (p = n.s.); 3-uncomplicated embolism syndrome: n = 30 (48.4%), of whom 20 in group A and 10 in group B (p = n.s.). CONCLUSIONS: In our study, history and signs of deep vein thrombosis were the only clues significantly more represented in early diagnosed cases. The possibility of thromboembolic accident should never be dismissed, even despite lack of a proven emboligenous cause in patients with unexplained chest pain or cardiorespiratory failure.

Immunoreactivity of chimeric proteins carrying the HIV-1 epitope IGPGRAF. Correlation between predicted conformation and antigenicity.

Sera from HIV-1 infected individuals were examined for their reactivity to the principal neutralizing domain, IGPGRAF sequence, of the V3-loop of HIV-1. Four hybrid proteins carrying this sequence inserted in four different outer loops of a protein that makes up the capsid of an insect virus were used as antigen in a Western blot assay for this survey. All the four antigens showed different activity: sera that recognise all antigens to sera that reacted with only one of them. Competition experiments indicated that the antibodies recognised these proteins with different affinity. Molecular modelling of the hybrid proteins predicted that the inserted sequence adopted different conformations in each position. Comparison of predicted most stable conformations for IGPGRAF indicated that there is a close relationship between conformational similarity to a V3-loop reference structure and the degree of reactivity with sera.

Platelet count and platelet function in patients with angina pectoris (before and after a cycloergometric exercise test).

Platelet count and platelet function (circulating platelet aggregates, retention by glass beads and aggregation) were studied under basal conditions and after a cycloergometric exercise test in 10 subjects with stable angina pectoris and 10 normal subjects. There were no baseline differences between patients and controls in any of the tests of platelet function, nor did the values change after the exercise test. There was, however, a significant increase in the number of circulating platelets after the test in angina patients. Possible reasons for this phenomenon are discussed, with emphasis on the role of catecholamine hypersecretion induced by the physical exercise.

A polygraph study of ischemic heart disease: behavior of systolic times in acute myocardial infarction.

The authors investigated systolic time intervals in 28 cases of acute myocardial infarction (AMI). Polygraph recordings were made on the first day of illness and repeated at two, three, five, and seven hospital days. The patients were divided into two groups: one with a contributory history of ischemic and/or hypertensive heart disease (Group PH for "positive history") and one without such history (Group NH for "negative history"). The influence of numerous variables on systolic times were explored in both groups, and the emerging data were processed by multiple stepwise regression analysis. The results show that the left ventricular ejection time (LVET) is invariably shortened in AMI, whereas the pre-ejection indices (PEP and ICT) afford definite differentiation of patients of Group PH (with lengthened PEP and ICT values) from those of Group NH (shortened PEP and ICT). The authors emphasize the importance of obtaining polygraph recordings very early in the course of AMI and of taking into account the patient's history in view of a correct assessment of pre-ejection times.