Evidence of Covid-19 lockdown effects on riverine dissolved organic matter dynamics provides a proof-of-concept for needed regulations of anthropogenic emissions

The fast spread of SARS-CoV-2 virus in Italy resulted in a 3-months lockdown of the entire country. During this period, the effect of the relieved anthropogenic activities on the environment was plainly clear all over the country. Herein, we provide the first evidence of the lockdown effects on riverine dissolved organic matter (DOM) dynamics. The strong reduction in anthropogenic activities resulted in a marked decrease in dissolved organic carbon (DOC) concentration in the Arno River (-44%) and the coastal area affected by its input (-15%), compared to previous conditions. The DOM optical properties (absorption and fluorescence) showed a change in its quality, with a shift toward smaller and less aromatic molecules during the lockdown. The reduced human activity and the consequent change in DOM dynamics affected the abundance and annual dynamics of heterotrophic prokaryotes. The results of this study highlight the extent to which DOM dynamics in small rivers is affected by secondary and tertiary human activities as well as the quite short time scales to return to the impacted conditions. Our work also supports the importance of long-term research to disentangle the effects of casual events from the natural variability.

THU0257 ESTIMATED 10-YEARS CARDIOVASCULAR RISK IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS: PRELIMINARY RESULTS FROM THE “CARDIOVASCULAR OBESITY AND RHEUMATIC DISEASE (CORDIS)” STUDY GROUP OF THE ITALIAN SOCIETY OF RHEUMATOLOGY

Background:

Systemic lupus erythematosus (SLE) patients are at high risk for CV events, and EULAR recommends assessing the 10-year CV-risk using the Systematic Coronary Risk Evaluation (SCORE) [1]. The QRISK3, another score to assess CV-risk in UK population, considers different factors among which also SLE. The Progetto Cuore score (PCS) is validated to estimate CV risk in Italian people and largely replicates the SCORE project [2].

Objectives:

This cross-sectional study aimed to estimate CV-risk using SCORE, QRISK3 and, for the first time, PCS in a multicentric cohort of Italian SLE patients.

Methods:

During 2019 we evaluated 173 SLE patients (87.7% female; age 40±16 years; disease duration 138±105 months), fulfilling the 1997 ACR classification criteria. Clinical and laboratory data were registered, and individual CV-risk was calculated using suitable algorithms for the SCORE, QRISK3 and PCS. Statistical analysis was performed using Graphpad Instat 8.0 (San Diego, CA-USA).

Results:

In 13 (7%) SLE patients a previous CV event was recorded. Hypertension was present in 60 (37.5%) and diabetes in 27 (16.9%) patients. Mean total cholesterol was 184±39 mg/dL, HDLc 58±18 mg/dL, LDLc 124±37 mg/dL, triglycerides 105±63 mg/dL; dyslipidaemia was reported in 58 (36.2%) patients and 29 (18.1%) were on statin. Mean BMI was 24.9±5.3 Kg/sm, 60 (37.5%) and 23 (14.3%) patients were overweight and obese, while 25 (15.6%) patients were smokers. 87 (54.3%) SLE patients had a SLEDAI<4, 91% of patients were taken HCQ and 65% were on prednisone (mean dose 5.4±5.9 mg/day), but only 7.5% took >7.5 mg/day. The CV-risk of SLE patients according to SCORE, QRISK3 and PCS was 1.1±2.1%, 10.5±12.3% and 3.7±5.4%, respectively. Stratifying patients at low, moderate or high CV risk according to the PCS and SCORE a double proportion of patients was at moderate (8% vs 3.9%) or high (1.9% vs 0.9%) CV risk (p=0.03). Finally, CV-risk according to QRISK3 was higher than 20% (high risk) in 32/160 (20%) patients.

Conclusion:

This multicentre study demonstrated that the mean estimated CV-risk in SLE patients is globally low using the SCORE, QRISK3 and PCS. The PCS seems to better intercept those patients at moderate/high risk, at least in Italian SLE patients, while QRISK3 predicts the highest CV risk. The lack of disease-specific CV-risk factors (such as autoantibodies profile or organ involvement) probably account for the underestimation of CV risk using the SCORE and PCS.

References:

[1]ARD 2019;78(6):736-745.

[2]ARD 2019;0:1–2.doi:10.1136/annrheumdis-2019-215715

Disclosure of Interests:

Fabio Cacciapaglia Speakers bureau: BMS; Roche; Pfizer; Abbvie, Andreina Manfredi: None declared, Gianluca Erre: None declared, Elena Bartoloni Bocci: None declared, Garifallia Sakellariou Speakers bureau: Abbvie, Novartis, MSD, Ombretta Viapiana: None declared, Sergio Colella: None declared, Anna Abbruzzese: None declared, Marco Fornaro: None declared, Giacomo Cafaro: None declared, Maria Antonietta Fenu: None declared, Bianca Lucia Palermo: None declared, Martina Dessì: None declared, Adalgisa Palermo: None declared, Alessandro Giollo: None declared, Elisa Gremese Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Speakers bureau: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Francesca Romana Spinelli Grant/research support from: Pfizer, Speakers bureau: Lilly, BMS, Celgene, Fabiola Atzeni: None declared, Matteo Piga: None declared

THU0127 Estimated cardiovascular risk in a large cohort of rheumatoid arthritis patients from the “Cardiovascular Obesity and Rheumatic DISease (CORDIS)” Study Group of the Italian Society of Rheumatology

Background:

Rheumatoid arthritis (RA) patients present high cardiovascular (CV) morbidity and mortality and EULAR recommends estimating their CV-risk [1]. The Systematic Coronary Risk Evaluation (SCORE) algorithm is suggested if National Guidelines are lack, but few data are available about different strategies.

Objectives:

To estimate the 10-years CV-risk using different algorithms in RA compared to osteoarthritis (OA) patients, as control group.

Methods:

A total of 1467 RA patients (78.3% female; mean age 59.8±11.5 years; mean disease duration 131±109 months), fulfilling the 2010 EULAR/ACR classification criteria, and 342 age and sex matched patients with OA (79.8% female; mean age 58.7±11.5 years) were enrolled in this multicentre cross-sectional study during 2019. Clinical and laboratory data were registered, and individual CV-risk was calculated using: SCORE chart, “Progetto Cuore” model (PCM), QRisk3, Reynolds Risk Scores (RRS) and Expanded Risk Score in RA (ERS-RA), as stated by suitable algorithms. Statistical analysis was performed using the Statistical System Graphpad Instat 8.0 (San Diego, CA-USA).

Results:

In 46 (3%) RA patients a previous CV event was observed. Among traditional CV-risk factors, RA patients presented higher frequency of diabetes (9.9% vs 6.4%; p=0.04) and lower prevalence of dyslipidaemia (21.7% vs 32.5%; p<0.0001) compared to OA patients. Prevalence of hypertension was similar in both groups (40% vs 39.2%). Mean BMI (25.6±4.8 vs 26.6±4.4; p<0.0001) and prevalence of obesity (15% vs 21%; p=0.003) were significantly lower in RA patients. Finally, RA patients were more frequently smokers (20.4% vs 12.5% - p=0.002). 441 (30%) RA patients were in CDAI remission, 998 (68%) patients were on csDMARDs while a biologic agent was used in 617 (42%) patients. About 43% of RA patients were on a mean prednisone-dose of 4.5±3.5 mg/day. The 10-years CV-risk resulted 2 to 3-fold higher in RA compared to OA patients using the different algorithms. The QRisk3 estimated the highest CV risk in our cohort of patients, while the ERS-RA and RRS were significantly higher than PCM and SCORE.

Conclusion:

Our study demonstrates a higher estimated CV-risk in RA compared to OA patients. The commonly used algorithms to estimate CV-risk in clinical practice perform differently, evaluating different traditional CV-risk factors and disease specific characteristic, as for QRisk3 or ERS-RA. Rheumatologist should impact on both traditional and RA related modifiable CV-risk factors.

References:

[1]Agca R, et al. Ann Rheum Dis 2017;76:17–28.

Disclosure of Interests:

Fabio Cacciapaglia Speakers bureau: BMS; Roche; Pfizer; Abbvie, Matteo Piga: None declared, Gianluca Erre: None declared, Andreina Manfredi: None declared, Elena Bartoloni Bocci: None declared, Garifallia Sakellariou Speakers bureau: Abbvie, Novartis, MSD, Ombretta Viapiana: None declared, Sergio Colella: None declared, Anna Abbruzzese: None declared, Martina Dessì: None declared, Caterina Vacchi: None declared, Floriana Castagna: None declared, Giacomo Cafaro: None declared, Bianca Lucia Palermo: None declared, Alessandro GIollo: None declared, Marco Fornaro: None declared, Elisa Gremese Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Speakers bureau: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Janssen, Merck Sharp & Dohme, Novartis, Sanofi, UCB, Roche, Pfizer, Francesca Romana Spinelli Grant/research support from: Pfizer, Speakers bureau: Lilly, BMS, Celgene, Fabiola Atzeni: None declared

Elucidating the effect of the lead iodide complexation degree behind the morphology and performance of perovskite solar cells

The inclusion of iodide additives in hybrid perovskite precursor solutions has been successfully exploited to improve the solar cell efficiency but their impact on perovskite formation, morphology and photovoltaic performance is still not clear. Here an extensive analysis of the effect of iodide additives in the solution-phase and during the perovskite film formation, as well as their effect on device performance is provided. The results demonstrate that in the solution-phase the additives promote the formation of lead poly-iodide species resulting in the disaggregation of the inorganic lead iodide framework and in the formation of smaller nuclei inducing the growth of uniform and smooth perovskite films. Most importantly, the complexation capability of different iodide additives does not only directly affect film morphology but also influences the density of defect states by varying the stoichiometry of precursors. These findings demonstrate that the fine control of the interactions of the chemical species in the solution-phase is essential for the precise control of the morphology at the nanoscale and the growth of the perovskite films with a reduced density of defect states. Therefore, the in-depth understanding of all the processes involved in the solution-phase is the first step for the development of a facile and reproducible approach for the fabrication of hybrid perovskite solar cells with enhanced photovoltaic performance.

An unusual thoracic localizations of Erdheim- Chester disease: A case report

Erdheim- Chester disease is a rare non- Langerhans cell histiocytosis that usually involves the bones, heart, central nervous system, retroperitoneum, eyes, kidneys, skin and adrenals. Lungs are affected in up to one-half cases; at CT scan various patterns are described: interstitial disease, consolidations, micronodules and microcysts, with or without pleural involvement. We presented a case of a 59 year-old man with unusual intrathoracic manifestation of Erdheim- Chester disease. Singularities of our report are the lonely thoracic involvement at the onset of the disease and a histiocytic lesion in the posterior mediastinum.

Cytokine modulation in patients with idiopathic pulmonary fibrosis undergoing treatment with steroids, immunosuppressants, and IFN-γ 1b

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown etiology and pathogenic mechanisms. From an etiopathogenic point of view, alveolar macrophages play a key role in accumulation of fibroblasts and deposition of collagen and extracellular matrix by releasing specific cytokines and inflammatory mediators. IPF seems to be also associated with circulating fibrocytes, which might be involved with an abnormal pulmonary vascular repair and remodeling. Based on its hypothesized pathologic mechanisms, anti-inflammatory, anti-fibrotic and immunosuppressive therapies are often used. For these reasons, Interferon-g (IFN-g) has been used to exploit its activity on macrophages and fibroblasts. The aim of this study was to investigate the response to corticosteroids and/or IFN-g 1b treatments based on pulmonary function tests and on inflammatory cytokine patterns of expression on bronchoalveolar lavage (BAL), at baseline and during and after the therapies. Unlike previous studies, we analyzed a period of therapy longer than 1 year. Our results demonstrated the effectiveness of IFN-γ in a group of IPF patients in whom the treatment was prolonged for over a year. These data suggest a positive role of IFN-γ; treatment in patients in the initial stage of the disease.

Absorption correction and phase function shape effects on the closure of apparent optical properties

We present a closure experiment between new inherent optical properties (IOPs: absorption a, scattering b, backscattering b_b) and apparent optical properties (AOPs: remote-sensing reflectance R_rs, irradiance reflectance R, and anisotropic factor at nadir Q_n) data of Ionian and Adriatic seawaters, from very clear to turbid waters, ranging across one order of magnitude in R_rs. The internal consistency of the IOP-AOP matchups was investigated though radiative transfer closure. Using the in situ IOPs, we predicted the AOPs with the commercial radiative transfer solver Hydrolight. Closure was limited by two unresolved issues, one regarding processing of in situ data and the other related to radiative transfer modeling. First, different correction methods of the absorption data measured by the Wetlabs ac-s produced high variations in simulated reflectances, reaching 40% for the highest reflectances in our dataset. Second, the lack of detailed volume scattering function measurements forces us to adopt analytical functions that are consistent with a given particle backscattering ratio. The analytical phase functions named Fournier-Forand and two-term Kopelevich presented reasonable angular shapes with respect to measurements at a few backward angles. Between these phase functions, induced changes were within 4% for R_rs, within 11% for R, and within 10% for Q_n. Additionally, closure of Q_n was generally not successful considering radiometric uncertainties. Simulated Q_n overestimated low values and underestimated high values, especially at 665 nm, where Hydrolight was unable to predict measured Q_n values greater than 6 sr. The physical nature of Q_n makes this mismatch almost independent of the measured IOPs, thus precluding Q_n tuning by varying the former. The non-closure of Q_n might be caused by an inaccurate phase function and, to a lesser extent, by the modeling of the incoming radiance. For the future, this remains the task of accurate absorption and phase function measurements, especially at red wavelengths.

Endobronchial-ultrasound needle aspiration and endoscopic ultrasound-fine-needle aspiration in thoracic diseases

EBUS-TBNA and EUS-FNA are minimally invasive techniques rapidly gaining ground in the non-surgical invasive diagnostic approach to thoracic diseases due to their high accuracy and low morbidity and mortality compared to surgical techniques. Moreover, in the diagnosis and staging of lung cancer the combination of the two techniques is superior to either test alone. In this review we focus on the role of EBUS-TBNA and EUS-FNA in both malignant and non-malignant thoracic diseases.

Hierarchical multiple peeling simulations

We model hierarchical multiple peeling through finite element simulations, quantifying how hierarchy optimizes the strength of the bioinspired attachment.

LRRTM1 on chromosome 2p12 is a maternally suppressed gene that is associated paternally with handedness and schizophrenia

Left-right asymmetrical brain function underlies much of human cognition, behavior and emotion. Abnormalities of cerebral asymmetry are associated with schizophrenia and other neuropsychiatric disorders. The molecular, developmental and evolutionary origins of human brain asymmetry are unknown. We found significant association of a haplotype upstream of the gene LRRTM1 (Leucine-rich repeat transmembrane neuronal 1) with a quantitative measure of human handedness in a set of dyslexic siblings, when the haplotype was inherited paternally (P=0.00002). While we were unable to find this effect in an epidemiological set of twin-based sibships, we did find that the same haplotype is overtransmitted paternally to individuals with schizophrenia/schizoaffective disorder in a study of 1002 affected families (P=0.0014). We then found direct confirmatory evidence that LRRTM1 is an imprinted gene in humans that shows a variable pattern of maternal downregulation. We also showed that LRRTM1 is expressed during the development of specific forebrain structures, and thus could influence neuronal differentiation and connectivity. This is the first potential genetic influence on human handedness to be identified, and the first putative genetic effect on variability in human brain asymmetry. LRRTM1 is a candidate gene for involvement in several common neurodevelopmental disorders, and may have played a role in human cognitive and behavioral evolution.

Reduced expression of the Aalpha subunit of protein phosphatase 2A in human gliomas in the absence of mutations in the Aalpha and Abeta subunit genes

Protein phosphatase 2A (PP2A) consists of 3 subunits: the catalytic subunit, C, and the regulatory subunits, A and B. The A and C subunits both exist as 2 isoforms (alpha and beta) and the B subunit as multiple forms subdivided into 3 families, B, B' and B". It has been reported that the genes encoding the Aalpha and Abeta subunits are mutated in various human cancers, suggesting that they may function as tumor suppressors. We investigated whether Aalpha and Abeta mutations occur in human gliomas. Using single strand conformational polymorphism analysis and DNA sequencing, 58 brain tumors were investigated, including 23 glioblastomas, 19 oligodendrogliomas and 16 anaplastic oligodendrogliomas. Only silent mutations were detected in the Aalpha gene and no mutations in the Abeta gene. However, in 43% of the tumors, the level of Aalpha was reduced at least 10-fold. By comparison, the levels of the Balpha and Calpha subunits were mostly normal. Our data indicate that these tumors contain very low levels of core and holoenzyme and high amounts of unregulated catalytic C subunit.

Impaired insulin-like growth factor I vasorelaxant effects in hypertension

Insulin-like growth factor I (IGF-I) can be considered a factor potentially involved in arterial hypertension not only for its growth-promoting features but also for its effects on vascular tone. Nevertheless, the actions of the hormone on vascular reactivity are still unexplored in hypertension. Therefore, the vasodilation induced by increasing doses of IGF-I and the modulation of norepinephrine vasoconstriction induced by low levels of the hormone were tested on aortic rings of spontaneously hypertensive and normotensive rats. The results indicate that the vasodilation evoked by IGF-I is impaired in hypertensive rats (Delta% of maximal vasorelaxation, 30+/-1 versus 41+/-1; P<0.01), and after the removal of endothelium or the inhibition of endothelial NO synthase, the vasodilation evoked by the hormone was blunted in both rat strains and became similar between hypertensive and normotensive rats (Delta% of maximal vasorelaxation, 21+/-1 versus 20+/-1; P=NS). Moreover, IGF-I does not show any effect on norepinephrine vasoconstriction in hypertensive rats, and this alteration may depend on the lack of sensitizing effect exerted by IGF-I on alpha(2)-adrenergic-evoked NO vasorelaxation. The defect in IGF-I vascular action is also present in young spontaneously hypertensive rats (age 5 weeks). In conclusion, our data demonstrate that IGF-I vasorelaxant properties are impaired in spontaneously hypertensive rats, suggesting that such defect may play a causative or permissive role in the development of hypertensive conditions.

Mutation analysis of hBUB1, hBUBR1 and hBUB3 genes in glioblastomas

Glioblastomas, the most malignant human brain tumors, are characterized by marked aneuploidy, suggesting chromosomal instability which may be caused by a defective mitotic spindle checkpoint. We screened 22 glioblastomas for mutations in the mitotic spindle check-point genes hBUB1, hBUBR1 and hBUB3. DNA sequencing revealed a silent mutation at codon 144 of hBUB1 (CAG-->CAA, Gln-->Gln) in one glioblastoma, a silent mutation at codon 952 of hBUBR1 (GAC-->GAT, Asp-->Asp) in another glioblastoma, and a silent mutation at codon 388 of the hBUBR1 gene (GCG-->GCA, Ala-->Ala) in 8 glioblastomas. We also observed a known polymorphism at hBUBR1 codon 349 (CAA/CGA, Gln/Arg), with an allelic frequency of 0.75 for Gln and 0.25 for Arg, which is similar to that among healthy Caucasian individuals (0.73 vs 0.27). The coding sequence of the hBUB3 gene did not contain any mutation, but in 4 glioblastomas (18%), a C-->T point mutation was detected at position -6 (6 nucleotides upstream of the ATG initiator codon). Analysis of blood DNA of these patients showed identical sequence alterations, indicating that this is a polymorphism. Again, the frequency in glioblastomas was similar to that in healthy Caucasians (15%). We further screened hBUB1 in 18 cases of giant cell glioblastoma, a variant characterized by a predominance of bizarre, multinucleated giant cells. There were no changes, except for a silent mutation at codon 144 in two cases. These results suggest that mutations in these mitotic spindle checkpoint genes do not play a significant role in the causation of chromosomal instability in glioblastomas.

Gene expression profiling of low-grade diffuse astrocytomas by cDNA arrays

Diffuse astrocytoma WHO grade II is a well-differentiated, slowly growing tumor that has an inherent tendency to progress to anaplastic astrocytoma (WHO grade III) and, eventually, to glioblastoma (WHO grade IV). Little is known about its molecular basis, except for p53 mutations that are found in >60% of cases. In a search for additional genetic alterations, we carried out gene expression profiling of 11 diffuse astrocytomas using cDNA expression arrays. Expression of six genes (TIMP3, c-myc, EGFR, DR-nm23, nm23-H4, and GDNPF) was detected in 64-100% of diffuse astrocytomas, but not in nontumorous brain tissue. Seven genes (AAD14, SPARC, LRP, PDGFR-alpha, 60S ribosomal protein L5, PTN, and hBAP) were found to be up-regulated more than 2-fold in 20-60% of cases, whereas 11 genes (IFI 9-27, protein kinase CLK, TDGF1, BIN1, GAB1, TYRO3, LDH-A, adducin 3, GUK1, CDC10, and KRT8) were down-regulated to less than 50% of normal levels in 64-100% of cases. Semiquantitative conventional reverse transcription-PCR was performed for 11 genes, 9 of which showed an expression profile similar to that obtained with cDNA expression arrays. Immunohistochemical staining for SPARC showed cytoplasmic immunoreactivity of neoplastic cells in all diffuse astrocytomas analyzed. These results indicate significant changes in gene expression in diffuse astrocytomas, but it remains to be shown which of these are causally related to the transformation of glial cells.

Identical mutations in the CSB gene associated with either Cockayne syndrome or the DeSanctis-cacchione variant of xeroderma pigmentosum

Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are two hereditary disorders in which photosensitivity is associated with distinct clinical and cellular phenotypes and results from genetically different defects. We have identified the primary molecular alteration in two patients in whom clinical manifestations strongly reminiscent of a severe form of XP were unexpectedly associated with the CS cellular phenotype and with a defect in the CSB gene. Sequencing of the CSB -coding region in both cDNA and genomic DNA showed that these patients had identical alterations to those in a patient with the clinical features of the classical form of CS. These data, together with fluorescence in situ hybridization analysis, demonstrated that the two siblings with XP as well as the CS patient were homozygous for the same CSB mutated allele, containing a silent C2830T change and a nonsense mutation C2282T converting Arg735 to a stop codon. The finding that the same inactivating mutation underlies different pathological phenotypes indicates that there is no simple correlation between the molecular defect and the clinical features. Therefore, alterations in the CSB gene give rise to the same repair defect at the cellular level but other genetic and/or environmental factors determine the pathological phenotype.

Loss of heterozygosity on chromosome 10 is more extensive in primary (de novo) than in secondary glioblastomas

Glioblastomas develop de novo (primary glioblastomas) or through progression from low-grade or anaplastic astrocytoma (secondary glioblastomas). There is increasing evidence that these glioblastoma subtypes develop through different genetic pathways. Primary glioblastomas are characterized by EGFR and MDM2 amplification/overexpression, PTEN mutations, and p16 deletions, whereas secondary glioblastomas frequently contain p53 mutations. Loss of heterozygosity (LOH) on chromosome 10 (LOH#10) is the most frequent genetic alteration in glioblastomas; the involvement of tumor suppressor genes, other than PTEN, has been suggested. We carried out deletion mappings on chromosome 10, using PCR-based microsatellite analysis. LOH#10 was detected at similar frequencies in primary (8/17; 47%) and secondary glioblastomas (7/13; 54%). The majority (88%) of primary glioblastomas with LOH#10 showed LOH at all informative markers, suggesting loss of the entire chromosome 10. In contrast, secondary glioblastomas with LOH#10 showed partial or complete loss of chromosome 10q but no loss of 10p. These results are in accordance with the view that LOH on 10q is a major factor in the evolution of glioblastoma multiform as the common phenotypic end point of both genetic pathways, whereas LOH on 10p is largely restricted to the primary (de novo) glioblastoma.

Alterations in the CSB gene in three Italian patients with the severe form of Cockayne syndrome (CS) but without clinical photosensitivity

Cockayne syndrome (CS) is a rare autosomal recessive disorder characterized by postnatal growth failure, mental retardation and otherwise clinically heterogeneous features which commonly include cutaneous photosensitivity. Cultured cells from sun-sensitive CS patients are hypersensitive to ultraviolet (UV) light and, following UV irradiation, are unable to restore RNA synthesis rates to normal levels. This has been attributed to a specific deficiency in CS cells in the ability to carry out preferential repair of damage in actively transcribed regions of DNA. We report here a cellular and molecular analysis of three Italian CS patients who were of particular interest because none of them was sun-sensitive, despite showing most of the features of the severe form of CS, including the characteristic cellular sensitivity to UV irradiation. They all were altered in the CSB gene. The genetically related patients CS1PV and CS3PV were homozygous for the C1436T transition resulting in the change Arg453opal. Patient CS2PV was a compound heterozygote for two new causative mutations, insertions of an A at position 1051 and of TGTC at 2053, leading to truncated proteins of 367 and 681 amino acids. These mutations result in severely truncated proteins, as do many of those that we previously identified in several sun-sensitive CS-B patients. These observations confirm that the CSB gene is not essential for viability and cell proliferation, an important issue to be considered in any speculation on the recently proposed additional function of the CSB protein in transcription. Our investigations provide data supporting the notion that other factors, besides the site of the mutation, influence the type and severity of the CS clinical features.

Molecular analysis of mutations in the CSB (ERCC6) gene in patients with Cockayne syndrome

Cockayne syndrome is a multisystem sun-sensitive genetic disorder associated with a specific defect in the ability to perform transcription-coupled repair of active genes after UV irradiation. Two complementation groups (CS-A and CS-B) have been identified, and 80% of patients have been assigned to the CS-B complementation group. We have analyzed the sites of the mutations in the CSB gene in 16 patients, to determine the spectrum of mutations in this gene and to see whether the nature of the mutation correlates with the type and severity of the clinical symptoms. In nine of the patients, the mutations resulted in truncated products in both alleles, whereas, in the other seven, at least one allele contained a single amino acid change. The latter mutations were confined to the C-terminal two-thirds of the protein and were shown to be inactivating by their failure to restore UV-irradiation resistance to hamster UV61 cells, which are known to be defective in the CSB gene. Neither the site nor the nature of the mutation correlated with the severity of the clinical features. Severe truncations were found in different patients with either classical or early-onset forms of the disease.

Cloning a new human gene from chromosome 21q22.3 encoding a glutamic acid-rich protein expressed in heart and skeletal muscle

The identification and functional characterization of genes on chromosome 21 is a necessary step to understand the pathogenesis of the various phenotypic anomalies that affect Down syndrome patients. Using direct cDNA selection we have identified a new gene, SH3BGR, that maps to 21q22.3, proximal to HMG14, and is differentially expressed in heart and skeletal muscle. SH3BGR encodes a novel protein that is characterized by the presence of a proline-rich region containing the consensus sequence for a SH3-binding domain and by an acidic carboxyl-terminal region containing a glutamic acid-rich domain predicted to assume a coiled coil. The presence of two functional domains involved in protein-protein interactions suggests that SH3BGR could be part of a multimeric complex. Its overexpression might alter specific functions of muscular tissue and therefore take part in the pathophysiology of muscular hypotonia in Down syndrome.

Prenatal diagnosis of 30 fetuses at risk for fragile X syndrome

The results of 30 prenatal diagnoses for fragile X syndrome are reported. Amniotic fluid cells were examined in 1 case, fetal blood in 4, and chorionic villi samples in the others. Of the 5 fetuses analyzed by cytogenetic methods, 1 had showed 4% of fraXq27.3 expression sites and the pregnancy was terminated. For 1 diagnosis, linkage analysis was used: the female fetus turned out to be normal. In 24 fetuses, the direct analysis of the mutation by StB12.3 probe was performed: 6 female and 3 male fetuses were found to carry a full mutation and 1 female fetus was found to carry a premutation. In 3 cases, the diagnoses were verified on fetal blood samples. Several tissues of 2 aborted male fetuses were analyzed for the fragile X mutation. The results are reported and discussed.

Interaction of fibronectin with cultured human endothelial cells: characterization of the specific receptor

In this study we provide a characterization of the fibronectin (FN) binding to endothelial cells (EC), and we identify the FN binding site on these cells. 125I-FN binding to EC in suspension was time dependent and reached a plateau at 4 h. Cold FN inhibited this interaction in a concentration-dependent way, but vitronectin, fibrinogen, and IgG were poorly effective. About 80% of the total FN associated to EC at the equilibrium was specifically bound; of this, 60% was reversibly bound, while 20% appeared to be internalized. The FN binding was saturable and an apparent dissociation constant of about 0.23 x 10(-6) mol/L and a maximal number of binding sites of about 9.8 x 10(5) was estimated from binding isotherms. Autoradiography data showed that EC-associated 125I-FN was all in high mol wt form that did not enter the gel. We then characterize the FN receptor (FNR) in EC. An antiserum to the FNR isolated from human placenta inhibited FN binding to EC by 89%, and using the immunoblotting technique, it recognized two bands in the EC detergent extract of mol wt 125/160 Kd. This antiserum also recognized the EC membrane protein complex eluted from the FN affinity column by an arg-gly-asp (RGD) peptide. When this complex was included into liposomes, it poorly bound to FN. However, the binding was strikingly increased by addition of Mn in the buffer and was specific for FN in respect to other substrata. These data define the FN binding site in EC and indicate that it is functionally and structurally related to that isolated from human placenta.

Fibrinogen-endothelial cell interaction in vitro: a pathway mediated by an Arg-Gly-Asp recognition specificity

It has been previously shown that fibrinogen (FG) associates specifically with human umbilical vein and bovine aortic endothelial cells (EC) in culture and induces EC migration. In the present study, we have investigated whether the FG-EC interaction is mediated by an Arg-Gly-Asp (RGD) recognition specificity and whether EC membrane proteins related to platelet GPIIb-IIIa are involved. Highly purified radioiodinated human FG, containing no detectable fibronectin, interacted with cultured human and bovine EC in suspension in a time-dependent and specific manner. The binding was inhibited by EDTA. Two polyclonal antibodies to platelet GPIIb-IIIa, which immunoprecipitated a heterodimer molecule from EC, inhibited FG binding to EC. These same antibodies inhibited FG-induced EC migration in a dose-dependent manner as measured in a Boyden chamber. Preabsorption of the antibodies with purified platelet GPIIb-IIIa markedly reduced both inhibitory activities. A series of synthetic RGD-containing peptides inhibited FG binding to EC and FG-induced EC migration. Gly-Arg-Gly-Asp (GRGD) was the most active peptide tested in inhibiting FG binding and EC migration (ID50 of 30 microM), and conservative substitutions in the RGD sequence markedly reduced inhibitory activity (ID50 greater than 1,000 microM). These results indicate that FG binding and EC migration are events mediated by an RGD recognition specificity and that EC surface proteins immunologically related to the GPIIb-IIIa complex on platelets are involved in this recognition.

Chemotactic activity of recombinant human granulocyte colony-stimulating factor

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) induced migration across polycarbonate filters of human polymorphonuclear leukocytes (PMN). rhG-CSF was active in inducing PMN migration at concentrations greater than or equal to 10 to 100 U/mL (7 to 70 ng/mL). rhG-CSF did not contain appreciable levels of endotoxin contamination as assessed by Limulus amebocyte assay, and Polymixin B did not affect the chemotactic activity of rhG-CSF. A monoclonal anti-G-CSF antibody blocked the induction of migration by G-CSF, thus establishing that the cytokine was responsible for the activity of the recombinant preparation. Checkerboard analysis was performed by seeding different concentrations of G-CSF above and/or below the filter and revealed that the migratory response to this cytokine was best observed in the presence of a positive concentration gradient between the lower and upper compartments of the chamber, thus indicating an actual chemotactic effect. When different migrating cells were examined, rhG-CSF was inactive on large granular lymphocytes and endothelial cells under conditions in which appropriate reference attractants were active. In contrast, rhG-CSF elicited a chemotactic response in monocytes inhibited by specific antibody. Thus, G-CSF is a chemotactic signal for phagocytes. This cytokine, when produced at inflammatory sites, may contribute to the recruitment of phagocytes from the blood compartment to amplify resistance against certain noxious agents.

Fibronectin and vitronectin regulate the organization of their respective Arg-Gly-Asp adhesion receptors in cultured human endothelial cells

Human umbilical vein endothelial cells (ECs) adhere in vitro to proteins of the extracellular matrix including fibronectin (fn) and vitronectin (vn). Specific receptors for fn and vn have been previously characterized. These receptors belong to a family of membrane glycoproteins characterized (a) by being a transmembrane complex of two noncovalently linked subunits and (b) by recognizing the tripeptide Arg-Gly-Asp on their respective ligands. In this paper we investigated how vn and fn control the organization of their respective receptors over the surface of ECs. It was found that the clustering of individual receptors and the organization thereafter of focal contacts occurred only when ECs were exposed to the specific ligand and did not occur on the opposite ligand. The shape of receptor clusters was slightly different and a colocalization of the two receptors was found when ECs were cultured on a mixed matrix of fn plus vn. Adhesion was selectively inhibited by vn or fn receptor antibodies on their respective substrates. The clustering of both receptors preceded the association of vinculin with focal contacts and stress fiber formation. Also, the vn receptor, in the absence of associated fn receptor, was capable of inducing the organization of the membrane-microfilament interaction complex. Overall, these results indicate that individual matrix ligands induce only the clustering of their respective membrane receptors. The clustering of only one receptor is capable of supporting the subsequent formation of focal contacts and the local assembly of related cytoskeletal proteins.

The localization of a platelet GpIIb-IIIa-related protein in endothelial cell adhesion structures

Previous studies have shown that human endothelial cells (ECs) adhere to fibrinogen (fg) and fibronectin (fn) and organize their cytoskeleton on these substrata. However, the mechanism governing this chain of events is poorly known. In ECs glycoproteins immunologically and biochemically similar to the platelet membrane GpIIb-IIIa complex have been described. The functional role of this complex in ECs remains to be established. In this study we show that the antigens recognized by polyclonal antibodies raised against human platelet GpIIb-IIIa and crossreacting with the EC form have a discrete and well-organized distribution at cell adhesion structures. Indeed these antigens are located at vinculin-rich focal contacts found at the membrane insertion of microfilament bundles of the stress fiber type. They are also found at cell-to-cell contacts and, with a diffuse pattern, at the dorsal surface of ECs. GpIIb-IIIa antibodies, added to EC suspensions prior to plating, inhibit EC spreading on fg and vitronectin (vn) substrata in a concentration-dependent way. In contrast, the antibodies are very poorly active when the cells are seeded on fn-coated glass. The same antibodies, added to adherent cells, disrupt cell-to-cell contacts and cause their rounding and detachment. Overall these results indicate that EC GpIIb-IIIa complex is involved in controlling the adhesion mechanism of these cells to extracellular matrix proteins.

Fibrinogen induces adhesion, spreading, and microfilament organization of human endothelial cells in vitro

Human umbilical vein endothelial cells (ECs) have been shown to attach to a substratum of fibrinogen (fg). Later, ECs undergo spreading, organization of thick microfilament bundles of the stress fiber type, and formation of focal contacts (adhesion plaques) that correspond to accumulation of vinculin at the cytoplasmic aspect of the ventral membrane. The rate of attachment to fg and the type of spreading is virtually identical to that obtained on substrata coated with fibronectin (FN). Antibodies to fg, but not to FN, prevent EC adhesion to fg; conversely, antibodies to FN, but not to fg, prevent adhesion of ECs to a FN-coated substratum. The removal of residual FN contamination from fg preparations by means of DEAE-cellulose chromatography does not result in any difference in EC adhesion on fg. Moreover, pretreatment of cells with inhibitors of synthesis and release of proteins does not impair their adhesion capacity on an fg-coated substratum. In contrast, human arterial smooth muscle cells do not adhere and spread on fg substrata but do so on FN. The synthetic peptides (Gly-Arg-Gly-Asp[GRGD] and Gly-Arg-Gly-Asp-Ser-Pro[GRGDSP]) containing the tripeptide Arg-Gly-Asp (RGD), originally found to be responsible for the cell binding activity of FN, have been found to inhibit EC spreading and the redistribution of their cytoskeleton, including the formation of stress fibers and the localization of vinculin either on fg or on FN. Conversely, the synthetic peptide Arg-Gly-Gly (RGG) was completely uneffective in inhibiting the adhesion and the sequence of events leading to spreading and cytoskeletal organization. These results indicate that ECs, but not smooth muscle cells, specifically adhere and spread on an fg substratum and this occurs by recognition mechanisms similar to those reported for FN.

Chemotactic activity of human recombinant granulocyte-macrophage colony-stimulating factor

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) seeded in the lower compartment of chemotaxis chambers induced migration of human peripheral blood monocytes and polymorphonuclear phagocytes. rhGM-CSF was active in inducing phagocyte migration at concentrations as low as 10 CML units/ml (corresponding to 0.002 microgram), and maximal activity was observed at 10(2)-10(4)/ml. Checkerboard analysis performed by seeding different concentrations of rhGM-CSF above and below the filter revealed that maximal induction of migration required a positive concentration gradient between the lower and upper compartment, and that rhGM-CSF elicited an actual chemotactic response in phagocytes. Human umbilical vein endothelial cells and blood large granular lymphocytes (LGL) responded poorly or not at all (endothelial cells) to rhGM-CSF under conditions in which appropriate reference chemoattractants were active. The chemotactic activity of rhGM-CSF may serve to recruit phagocytic cells from the blood compartment to amplify resistance against noxious agents.