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Amyloidosis are a group of diseases in which soluble proteins aggregate and deposit in fibrillar conformation extracellularly in tissues. The effectiveness of therapeutic strategies depends on the specific protein involved, being crucial to accurately determine its nature. Moreover, following the diagnosis, the search for the mutation within relatives allows the clinical advice. Here we report the precise diagnosis and explored the possible reasons of the structural pathogenicity for a renal amyloidosis related to a fibrinogen Aα‐chain variant. Whole‐exome sequencing and GATK calling pipeline were leveraged to characterize the protein variant present in a patient with kidney failure. Bioinformatics strategies were applied to suggest potential explanations of the variants aggregation. Our pipeline allowed the identification of a single‐point variant of fibrinogen Aα‐chain, which opened the possibility of curative transplantation. In silico structural analysis suggested that the pathogenicity of the variant may be attributed to a heightened susceptibility to yield a peptide prone to deposit as an oligomer with a β‐sheet structure. Exploiting the comprehensive coverage of whole‐genome sequencing, we managed to fill a vacant stage in the diagnosis of hereditary amyloidosis and to stimulate the advancement in biomedicine. [ABSTRACT FROM AUTHOR]

Choking (or foreign body airway obstruction) is a widespread phenomenon with serious consequences of morbidity and mortality. Choking (often also called suffocation) can be caused by food or inedible objects and leads to various degrees of asphyxiation or lack of oxygen in the blood stream. The incidence is very high in both young children and adults, especially seniors. However, since not all choking episodes end up in the emergency room or become fatalities, they often escape statistics. Although episodes of choking from non-edible bodies are infrequent, they affect mostly young children. Three of the most common risks for choking in general are neurological disorders, dysphagia and dental issues (few or no teeth, unstable or unsuitable prosthesis or orthodontic appliances). The purpose of this study was to evaluate the risk factors of choking and ways to reduce/avoid this event. We reported data on a series of 138 patients admitted to the emergency department following a choking event, at a hospital in Rome, Italy. The age group of the analyzed population ranged from 1 to 88 years, with the most represented age group of these between 40 and 59, with a similar distribution between males and females. The types of foods on which people choked reflected the seasonal, traditional and local foods: 67% of patients reported choking on fish bones followed by meat bones (9%) and artichokes (3%). Three relevant non-food choking elements reported were: orthodontic items, toothpicks and pins (one occurrence each). We also reported on two clinical cases of patients choking on meat and a chicken bone. In conclusion, choking awareness and prevention are essential for implementing potential life-saving precautions. Prevention is the first tool to reduce the occurrence of this event, therefore it is necessary to analyze the risk factors and educate the population to eliminate them. Proper chewing and oral manipulation are paramount functions in preventing choking, along with meal-time supervision if little children and elderly. Then, it behooves the healthcare professionals to disseminate knowledge of emergency maneuvers (e.g., Heimlich maneuver) to be implemented in the event of choking. [ABSTRACT FROM AUTHOR]

Apolipoprotein A‐I (apoA‐I) has a key function in the reverse cholesterol transport. However, aggregation of apoA‐I single point mutants can lead to hereditary amyloid pathology. Although several studies have tackled the biophysical and structural consequences introduced by these mutations, there is little information addressing the relationship between the evolutionary and structural features that contribute to the amyloid behavior of apoA‐I. We combined evolutionary studies, in silico mutagenesis and molecular dynamics (MD) simulations to provide a comprehensive analysis of the conservation and pathogenic role of the aggregation‐prone regions (APRs) present in apoA‐I. Sequence analysis demonstrated that among the four amyloidogenic regions described for human apoA‐I, only two (APR1 and APR4) are evolutionary conserved across different species of Sarcopterygii. Moreover, stability analysis carried out with the FoldX engine showed that APR1 contributes to the marginal stability of apoA‐I. Structural properties of full‐length apoA‐I models suggest that aggregation is avoided by placing APRs into highly packed and rigid portions of its native fold. Compared to silent variants extracted from the gnomAD database, the thermodynamic and pathogenic impact of amyloid mutations showed evidence of a higher destabilizing effect. MD simulations of the amyloid variant G26R evidenced the partial unfolding of the alpha‐helix bundle with the concomitant exposure of APR1 to the solvent, suggesting an insight into the early steps involved in its aggregation. Our findings highlight APR1 as a relevant component for apoA‐I structural integrity and emphasize a destabilizing effect of amyloid variants that leads to the exposure of this region. [ABSTRACT FROM AUTHOR]

Introduction: In this paper, we investigated whether cholecalciferol supplementation may increase the risk of stone recurrence in patients with calcium nephrolithiasis and Vitamin D deficiency. Methods: Thirty-three stone formers (56 ± 17 years old, 12 males) with 25(OH)D < 20 ng/mL were considered. Calcium excretion and urine supersaturation with calcium oxalate (ßCaOx) and brushite (ßbsh) were evaluated, both before and after cholecalciferol supplementation. Values of ß > 1 mean supersaturation. Cholecalciferol was prescribed as oral bolus of 100,000–200,000 IU, followed by weekly (5000–10,000 IU) or monthly (25,000–50,000 IU) doses. Calcium intake varied between 800 and 1000 mg/day. In urine, total nitrogen (TNE) was taken as an index of protein intake, sodium as a marker of dietary intake, and net acid excretion (NAE) as an index of acid–base balance. Results: TNE, sodium, and NAE did not change during the study (p = ns). Compared to baseline values, after cholecalciferol, both serum calcium and phosphate did not vary (p = ns); 25(OH)D increased from 11.8 ± 5.5 to 40.2 ± 12.2 ng/mL (p < 0.01); 1.25(OH)2D increased from 41.6 ± 17.6 to 54 ± 16 pg/mL (p < 0.01); PTH decreased from 75 ± 27.2 to 56.7 ± 21.1 pg/mL (p < 0.01); urinary calcium increased from 2.7 ± 1.5 to 3.6 ± 1.6 mg/Kg b.w. (p < 0.01); ßbsh increased from 0.9 ± 0.7 to 1.3 ± 1.3 (p = 0.02); whereas ßCaOx varied but not significantly. Before cholecalciferol supplementation, 6/33 patients were hypercalciuric (i.e., urine Ca ≥ 4 mg/Kg b.w.) and increased to 13/33 after cholecalciferol supplementation (pX2 = 0.03). Conclusions: Cholecalciferol supplementation may increase calcium excretion, or reveal an underlying condition of absorptive hypercalciuria. This may increase both urine supersaturation with calcium salts and stone-forming risk. [ABSTRACT FROM AUTHOR]

Abstract The cascade of molecular events leading to Human apolipoprotein A–I (apoA–I) amyloidosis is not completely understood, not even the pathways that determine clinical manifestations associated to systemic protein deposition in organs such as liver, kidney and heart. About twenty natural variants of apoA–I were described as inducing amyloidosis, but the mechanisms driving their aggregation and deposition are still unclear. We previously identified that the mutant Gly26Arg but not Lys107-0 induced the release of cytokines and reactive oxygen species from cultured RAW 264.7 murine macrophages, suggesting that part of the pathogenic pathway could elicit of an inflammatory signal. In this work we gained deep insight into this mechanism and determined that Gly26Arg induced a specific pro-inflammatory cascade involving activation of NF-κB and its translocation into the nucleus. These findings suggest that some but not all apoA–I natural variants might promote a pro-oxidant microenvironment which could in turn result in oxidative processing of the variants into a misfolded conformation. [ABSTRACT FROM AUTHOR]

Among other components of the extracellular matrix (ECM), glycoproteins and glycosaminoglycans (GAGs) have been strongly associated to the retention or misfolding of different proteins inducing the formation of deposits in amyloid diseases. The composition of these molecules is highly diverse and a key issue seems to be the equilibrium between physiological and pathological events. In order to have a model in which the composition of the matrix could be finely controlled, we designed and synthesized crosslinked hydrophilic polymers, the so-called hydrogels varying the amounts of negative charges and hydroxyl groups that are prevalent in GAGs. We checked and compared by fluorescence techniques the binding of human apolipoprotein A-I and a natural mutant involved in amyloidosis to the hydrogel scaffolds. Our results indicate that both proteins are highly retained as long as the negative charge increases, and in addition it was shown that the mutant is more retained than the Wt, indicating that the retention of specific proteins in the ECM could be part of the pathogenicity. These results show the importance of the use of these polymers as a model to get deep insight into the studies of proteins within macromolecules. [ABSTRACT FROM AUTHOR]

This is the second part of an article on the metabolic diagnosis of nephrolithiasis, the first part of which was published in the previous issue of this journal. Here we report on three clinical cases representative of a rational diagnostic workup of nephrolithiasis in specific clinical contexts: secondary hyperuricemia, cystinuria, and primary hyperoxaluria. Nephrolithiasis is one of the most frequent causes of hospitalization in nephrology and urology units in our country and is an important source of discomfort in affected patients. Despite the availability of modern, minimally invasive endourological procedures to remove stones from the urinary tract, prevention of stone recurrences remains an essential strategy. Chemical analysis of stones, whether passed spontaneously or removed surgically, is a crucial step in etiological diagnostics aimed at devising adequate prevention strategies. Modern endoscopic lithotripsy techniques provide complete fragmentation of stones and, compared to extracorporeal shock wave lithotripsy, have the advantage of avoiding painful elimination of fragments through the urinary tract. This means, however, that stone fragments are often unavailable for analysis, thereby depriving the nephrologist of an important tool for diagnosis. As a consequence, metabolic evaluation tends to be the only means of establishing the etiology of stones and preventing their recurrence. We conclude that close collaboration between nephrologists and urologists is a prerequisite for optimizing the diagnosis and treatment of stone disease. [ABSTRACT FROM AUTHOR]

Methyl-β-cyclodextrins (MβCDs) are molecules that are extensively used to remove and to load cholesterol (Chol) from artificial and natural membranes; however, the mechanism of Chol extraction by MβCD from pure lipids or from complex mixtures is not fully understood. One of the outstanding questions in this field is the capability of MβCD to remove Chol from lipid domains having different packing. Here, we investigated the specificity of MβCD to remove Chol from coexisting macrodomains with different lipid packing. We used giant unilamellar vesicles (GUVs) made of 1,2-dioleoylphosphatidylcholine:1,2-dipalmitoylphatidylcholine:free cholesterol, 1:1:1 molar ratio at 27°C. Under these conditions, individual GUVs present Chol distributed into lo and ld phases. The two phases can be distinguished and visualized using Laurdan generalized polarization and two-photon excitation fluorescence microscopy. Our data indicate that MβCD removes Chol preferentially from the more disordered phase. The process of selective Chol removal is dependent on the MβCD concentration. At high concentrations, MβCD also removes phospholipids. [ABSTRACT FROM AUTHOR]

Metabolic diagnosis of nephrolithiasis. Clinical cases (Part I) Nephrolithiasis is one of the most frequent causes of hospitalization in nephrology and urology units in our country and is an important source of discomfort in affected patients. Despite the availability of modern, minimally invasive endourological procedures to remove stones from the urinary tract, prevention of stone recurrences remains an essential strategy. Chemical analysis of stones, whether passed spontaneously or removed surgically, is a crucial step in etiological diagnostics aimed at devising adequate prevention strategies. Modern endoscopic lithotripsy techniques provide complete fragmentation of stones and, compared to extracorporeal shock wave lithotripsy, have the advantage of avoiding painful elimination of fragments through the urinary tract. This means, however, that stone fragments are often unavailable for analysis, thereby depriving the nephrologist of an important tool for diagnosis. As a consequence, metabolic evaluation tends to be the only means of establishing the etiology of stones and preventing their recurrence. Among patients attending our kidney stone center, we selected five clinical cases representative of a rational diagnostic workup in specific clinical contexts. Two of these nephrolithiasis cases (in a patient with osteoporosis and in a patient with primary hyperparathyroidism) are reported here (Part I); the remaining three will be discussed in the next issue of this journal (Part II). [ABSTRACT FROM AUTHOR]

A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses. [ABSTRACT FROM AUTHOR]

This paper considers numerical simulations of fluid-structure interaction (FSI) problems in hemodynamics for idealized geometries of healthy cerebral arteries modeled by both nonlinear isotropic and anisotropic material constitutive laws. In particular, it focuses on an anisotropic model initially proposed for cerebral arteries to characterize the activation of collagen fibers at finite strains. In the current work, this constitutive model is implemented for the first time in the context of an FSI formulation. In this framework, we investigate the influence of the material model on the numerical results and, in the case of the anisotropic laws, the importance of the collagen fibers on the overall mechanical behavior of the tissue. With this aim, we compare our numerical results by analyzing fluid dynamic indicators, vessel wall displacement, Von Mises stress, and deformations of the collagen fibers. Specifically, for an anisotropic model with collagen fiber recruitment at finite strains, we highlight the progressive activation and deactivation processes of the fibrous component of the tissue throughout the wall thickness during the cardiac cycle. The inclusion of collagen recruitment is found to have a substantial impact on the intramural stress, which will in turn impact the biological response of the intramural cells. Hence, the methodology presented here will be particularly useful for studies of mechanobiological processes in the healthy and diseased vascular wall. [ABSTRACT FROM AUTHOR]

Background: The senescence of the immune system is a complex phenomenon, characterized by impairment of several lymphocyte activities and generally considered a state of immune dysregulation. Aging is a condition associated with many social changes likely to induce psychological stress, which is often perceived as uncontrollable and can lead, in some cases, to clinically relevant depression. In the recent years a growing interest has been raised for the study of bidirectional interactions between the central nervous system and the immunological network (psychoneuroimmunology).Objective and Methods: We analyzed the possibility that chronic psychological distress and depression could worsen some immune functions in the aged. We postulate the neuroendocrine mechanisms of psychoimmune interaction, analyzing both the human and animal studies focused on aging.Results: The data from the literature reviewed suggest a significant impact of affective disorders on immune functions in the elderly subjects. This psychoimmune imbalance appears particularly important when the studies are carried out in otherwise healthy aged people.Conclusions: Here we reviewed the relationships between psychological stress and depression and immunological functions, with particular regard to those aspects pertinent to the aging process. The clinical relevance of these interactions remains to be elucidated, but the high frequency in the aged of autoimmune, infectious, and neoplastic diseases suggests to focus on the psychoneuroimmune interactions in the old age. We also propose some outlines for future studies concerning psychoneuroimmunology and aging. [ABSTRACT FROM AUTHOR]

Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins. This protein has key functions in lipoprotein metabolism and its plasma concentration is inversely correlated with the incidence of atherosclerosis and cardiovascular diseases. There is an increasing need to develop methods for efficient production of recombinant apoA-I for using it in basic research or pharmacological therapy. An apoA-I variant lacking two amino acid residues at the N-terminus can be easily produced by bacterial expression. We report here the characterization of this variant comparing its properties with those of the protein isolated from human serum. The results validate the use of this variant in future assays and investigations. [ABSTRACT FROM AUTHOR]

Human apolipoprotein A-I (apoA-I)-derived amyloidosis can present with either wild-type (Wt) protein deposits in atherosclerotic plaques or as a hereditary form in which apoA-I variants deposit causing multiple organ failure. More than 15 single amino acid replacement amyloidogenic apoA-I variants have been described, but the molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here, we have investigated by fluorescence and biochemical approaches the stabilities and propensities to aggregate of two disease-associated apoA-I variants, apoA-IGly26Arg, associated with polyneuropathy and kidney dysfunction, and apoA-ILys107-0, implicated in amyloidosis in severe atherosclerosis. Results showed that both variants share common structural properties including decreased stability compared to Wt apoA-I and a more flexible structure that gives rise to formation of partially folded states. Interestingly, however, distinct features appear to determine their pathogenic mechanisms. ApoA-ILys107-0 has an increased propensity to aggregate at physiological pH and in a pro-inflammatory microenvironment than Wt apoA-I, whereas apoA-IGly26Arg elicited macrophage activation, thus stimulating local chronic inflammation. Our results strongly suggest that some natural mutations in apoA-I variants elicit protein tendency to aggregate, but in addition the specific interaction of different variants with macrophages may contribute to cellular stress and toxicity in hereditary amyloidosis. [ABSTRACT FROM AUTHOR]

Cellular membranes are heterogeneous in composition, and the prevailing theory holds that the structures responsible for this heterogeneity in vivo are small structures (10-200 nm), sterol- and sphingolipid-enriched, of different sizes, highly dynamic denominated rafts. Rafts are postulated to be platforms, which by sequestering different membrane components can compartmentalize cellular processes and regulate signaling pathways. Despite an enormous effort in this area, the existence of these domains is still under debate due to the characteristics of the structures itself: small in size and highly mobile, which from the technical point of view implies using techniques with high spatial and temporal resolution. In this report we measured rapid fluctuations of the normalized ratio of the emission intensity at two wavelengths of Laurdan, a membrane fluorescent dye sensitive to local membrane packing. We observed generalized polarization fluctuations in the plasma membrane of intact rabbit erythrocytes and Chinese hamster ovary cells that can be explained by the existence of tightly packed micro-domains moving in a more fluid background phase. These structures, which display different lipid packing, have different sizes; they are found in the same cell and in the entire cell population. The small size and characteristic high lipid packing indicate that these micro-domains have properties that have been proposed for lipid rafts. [ABSTRACT FROM AUTHOR]

Amyloidoses constitute a group of diseases in which soluble proteins aggregate and deposit extracellularly in tissues. Nonhereditary apolipoprotein A-I (apoA-I) amyloid is characterized by deposits of nonvariant protein in atherosclerotic arteries. Despite being common, little is known about the pathogenesis and significance of apoA-I deposition. In this work we investigated by fluorescence and biochemical approaches the impact of a cellular microenvironment associated with chronic inflammation on the folding and pro-amyloidogenic processing of apoA-I. Results showed that mildly acidic pH promotes misfolding, aggregation, and increased binding of apoA-I to extracellular matrix elements, thus favoring protein deposition as amyloid like-complexes. In addition, activated neutrophils and oxidative/proteolytic cleavage of the protein give rise to pro amyloidogenic products. We conclude that, even though apoA-I is not inherently amyloidogenic, it may produce non hereditary amyloidosis as a consequence of the pro-inflammatory microenvironment associated to atherogenesis. [ABSTRACT FROM AUTHOR]

An excess of intracellular free cholesterol (Chol) is cytotoxic, and its homeostasis is crucial for cell viability. Apolipoprotein A-I (apoA-I) is a highly efficient Chol acceptor because it activates complex cellular pathways that tend to mobilize and export Chol from cellular depots. We hypothesize that membrane composition and/or organization is strongly involved in Chol homeostasis. To test this hypothesis, we constructed a cell line overexpressing stearoyl coenzyme A (CoA) desaturase (SCD cells), which modifies plasma membrane (PM) composition by the enrichment of monounsaturated fatty acids, and determined this effect on membrane properties, cell viability, and Chol homeostasis. PM in SCD cells has a higher ratio of phospholipids to sphingomyelin and is slightly enriched in Chol. These cells showed an increase in the ratio of cholesteryl esters to free Chol; they were more resistant to Chol toxicity, and they exported more caveolin than control cells. The data suggest that cell functionality is preserved by regulating membrane fluidity and Chol exportation and storage. [ABSTRACT FROM AUTHOR]

Colorectal cancer is one of the most common cancers in developed countries. Increasing numbers of early stage colorectal cancers and precancerous adenomatous lesions, polypoidal type lesions, and flat and depressed type lesions can be visualised and treated endoscopically thanks to endoscopic ultrasonography, high magnification chromoendoscopy and other technical advances. Polypectomy is generally considered for protuberant lesions, with both sessile and pedunculate morphology, and endoscopic mucosal resection (EMR) is indicated for superficial, flat or depressed types of lesions. Endoscopic therapy for colonic adenoma with dysplasia and early colorectal cancer is more advantageous than the conventional operative treatment, in that it is a relatively non-invasive and less costly method. However, endoscopic therapy is completely ineffective in lesions with lymph node or distant metastasis. Therefore, it is becoming more and more important to understand the correct indications and limitations of endoscopic polypectomy/mucosectomy as well as complication rates and the correct follow-up schedule. [ABSTRACT FROM AUTHOR]

Background: Between peripheral blood and tissue-infiltrating lymphocytes there is an intermediate compartment, the blood of the organ-draining vessels, which could show unusual features. The aim of the present study was to analyse the characteristics of the lymphocytes from the stomach-draining vessels and the cytokine secretion by these lymphocytes. The CagA-mediated lymphocyte activation in Helicobacter pylori-infected subjects and the humoral response to this antigen were evaluated and correlated with clinical data. Methods: We studied lymphocyte proliferation either with mitogens or with the CagA antigen and cytokine production and IgG anti-CagA by means of an enzyme-linked immunosorbent assay in peripheral blood and gastric-vein blood obtained during surgical intervention. Results: We showed higher proliferative response and cytokine production in lymphocytes from the gastric vein. The mitogenic response to the CagA antigen was highly specific but poorly sensitive for the H. pylori infection in both the compartments. The overall cytokine profile in our patients affected by non-ulcer disease was of the Th0 type. Conclusions: Gastric-vein-derived lymphocytes seem to show unusual features, as they behave like peripheral blood lymphocytes but show higher responses to all the tested stimuli. It is possible that the interaction of the lymphocytes with the mucosal environment could activate the synthetic mechanisms, making the cells more `responsive' to the stimulation. The CagA antigen is able to induce a specific T-lymphocyte response and is therefore a valid candidate antigen for the development of a vaccine. [ABSTRACT FROM AUTHOR]

Academic stress is a good model of psychological stress in humans for studying psychoneuroimmune correlations. We looked for correlations between psychological scores, immune tests and plasma levels of cortisol and neuropeptide Y (NPY). A group of medical students were evaluated at the beginning of the academic year (Baseline) and the day before an examination (Stress). They underwent evaluation by The Profile of Mood States (POMS), The Malaise Inventory, The Self Efficacy Scale and A Global Assessment of Recent Stress (GARS). The lymphocyte subsets, the lymphocyte proliferative response and the cytokine production were also evaluated. We detected modifications of some psychological test scores between the Baseline and Stress evaluation, a significant reduction of lymphocyte proliferation, IL-2 production and percentage of the lymphocyte CD19, and an increase in plasma cortisol levels during stress. The lymphocyte proliferation negatively correlated with the POMS score as well as the percentage of CD16+ cells with NPY plasma levels. NPY levels were not different from Baseline. The emotional and mood states seem to influence immunity.Copyright © 1999 S.Karger AG, Basel [ABSTRACT FROM AUTHOR]

Little research within the field of developmental or educational psychology has addressed teachers' perceptions of the characteristics of children who interact in different types of peer organizations. This study was designed to examine teachers' perceptions of the characteristics of boys and girls who interact in groups or in dyads. Participants (teachers and children) were recruited from 10 classes from all grade levels of 2 elementary schools. The children were asked to name those in their classes who played together frequently. On the basis of participants' responses, 2 categories of target children were identified: those who played with at least 3 other children (group) and those children who played with 1 other child (dyad). Two teachers then rated each target child on 6 characteristics. The results indicated that, compared with children who played in dyads, target children who played in groups were rated by teachers as being more competitive, receiving more attention from peers, valuing their friends more, and being more emotionally expressive. No differences were found between target children who played in groups or dyads in empathy or self-confidence. In addition, no interaction between sex and type of social organization was found for any of the measures. Results are discussed in terms of the relation between social organization and functions of peer relations. [ABSTRACT FROM AUTHOR]

The influence of a fat-free diet on the molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) of rat liver microsomes was studied by using reversed-phase high-pressure liquid chromatography. In the three phosphoglyceride classes analyzed, the fat-free diet produced a large decrease in the 18:0/20:4n−6 species but less important changes were found in the 16:0/20:4n−6 species. In PC, the most abundant phosphoglyceride class of rat liver microsomes, the fall in the 18:0/20:4n−6 species was counterbalanced mainly by an enhancement in the 16:0/18:1n−9 species although it was not evident in PE. In PI, the decrease in the 18:0/20:4n−6 species was counterbalanced by an increase in the 18:0/20:3n−9 species. Fluorescence polarization measurements of 1,6-diphenyl-1,3,5-hexatriene in liposomes of 16:0/18:1n−9-, 18:0/18:1n−9-, 16:0/20:4n−6-, and 18:0/20:4n−6-PC indicated that the change in the saturated fatty acid in the sn-1 position accompanying the replacement of 20:4n−6 by 18:1n−9 could be very important for a homeoviscous compensation, maintaining the membrane physical properties without large alterations in spite of the essential fatty acid deficiency due to the fat-free diet. [ABSTRACT FROM AUTHOR]

To investigate the presence of reduced bone mineral density (BMD) and to assess determinants of bone loss in rheumatoid arthritis, 45 female patients suffering from non-steroid treated rheumatoid arthritis were submitted to dual photon absorptiometry of the lumbar spine and to laboratory tests for calcium metabolism. The rheumatoid arthritis patients were divided into two groups according to anatomic grade and functional class; no abnormalities in calcium metabolism were defected whereas BMD was significantly lower in the third and fourth grade and in the third and fourth class patients ( P<0.005 versus controls, versus grades I and II and versus classes 1 and 2). BMD was significantly correlated with age ( P<0.001) and years postmenopausal ( P<0.01), but not with duration of disease. By multiple inear regression we derived an equation predictive of BMD. Osteoporosis in rheumatoid arthritis is observed even in non-corticosteroid treated patients; articular lesions with subsequent reduction in physical activity appear to play an important role in axial bone loss in rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

We prove that it is possible to associate to each infinitesimal model on a Euclidean vector space V a locally homogeneous Riemannian manifold. As an application, we characterize, in the space of the algebraic curvature tensors on V, the orbits which can occur for locally homogeneous Riemannian manifolds. [ABSTRACT FROM AUTHOR]

Some «natural» metrics on the tangent and on the sphere tangent bundle of Riemannian manifold are constructed and studied via the moving frame method. [ABSTRACT FROM AUTHOR]

Juxtaarticular osteoporosis is a recognized clinical feature in both rheumatoid arthritis (RA) and psoriatic arthritis (PA), while generalised osteopenia seems to be characteristic of RA only. To assess differences in bone turnover in the two forms of disease, we measured serum osteocalcin levels and other parameters of bone metabolism in two groups of female, ambulant, age-matched patients suffering from active RA or active PA and never treated with steroid therapy. Serum osteocalcin levels were significantly higher in RA patients than in PA patients (13.05±1.27 ng/ml vs 4.83±0.88 ng/ml; p<0.001), with a significant positive correlation between osteocalcin and serum alkaline phosphatase in both groups. These data suggest that bone turnover is higher in active RA than in active PA. Juxtaarticular osteoporosis could be mediated by local disease mechanisms both in RA and in PA, while factors specifically related to active RA seem to determine a more generalized impairment of bone turnover. [ABSTRACT FROM AUTHOR]

We first prove that a Riemannian manifold $(M,g)$ with globally constant additive Weyl invariants is locally homogeneous. Then we use this result to show that a manifold $(M,g)$ whose Laplacian commutes with all invariant differential operators is a locally homogeneous space. [ABSTRACT FROM AUTHOR]