Role of Endothelium in Cardiovascular Sequelae of Long COVID

The global action against coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 infection, shed light on endothelial dysfunction. Although SARS-CoV-2 primarily affects the pulmonary system, multiple studies have documented pan-vascular involvement in COVID-19. The virus is able to penetrate the endothelial barrier, damaging it directly or indirectly and causing endotheliitis and multi-organ injury. Several mechanisms cooperate to development of endothelial dysfunction, including endothelial cell injury and pyroptosis, hyperinflammation and cytokine storm syndrome, oxidative stress and reduced nitric oxide bioavailability, glycocalyx disruption, hypercoagulability, and thrombosis. After acute-phase infection, some patients reported signs and symptoms of a systemic disorder known as long COVID, in which a broad range of cardiovascular (CV) disorders emerged. To date, the exact pathophysiology of long COVID remains unclear: in addition to the persistence of acute-phase infection mechanisms, specific pathways of CV damage have been postulated, such as persistent viral reservoirs in the heart or an autoimmune response to cardiac antigens through molecular mimicry. The aim of this review is to provide an overview of the main molecular patterns of enduring endothelial activation following SARS-CoV-2 infection and to offer the latest summary of CV complications in long COVID.

Gut Microbiota and Cardiovascular Disease: Evidence on the Metabolic and Inflammatory Background of a Complex Relationship

Several studies in recent years have demonstrated that gut microbiota-host interactions play an important role in human health and disease, including inflammatory and cardiovascular diseases. Dysbiosis has been linked to not only well-known inflammatory diseases, such as inflammatory bowel diseases, rheumatoid arthritis, and systemic lupus erythematous, but also to cardiovascular risk factors, such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus. The ways the microbiota is involved in modulating cardiovascular risk are multiple and not only related to inflammatory mechanisms. Indeed, human and the gut microbiome cooperate as a metabolically active superorganism, and this affects host physiology through metabolic pathways. In turn, congestion of the splanchnic circulation associated with heart failure, edema of the intestinal wall, and altered function and permeability of the intestinal barrier result in the translocation of bacteria and their products into the systemic circulation, further enhancing the pro-inflammatory conditions underlying cardiovascular disorders. The aim of the present review is to describe the complex interplay between gut microbiota, its metabolites, and the development and evolution of cardiovascular diseases. We also discuss the possible interventions intended to modulate the gut microbiota to reduce cardiovascular risk.

High prevalence of lower limb atherosclerosis is linked with the gut-liver axis in patients with primary biliary cholangitis

BACKGROUND AND AIMS

Hypercholesterolemia is frequent in people with primary biliary cholangitis (PBC); however, it does not seem to confer an increased risk of cardiovascular disease. We aimed to evaluate the prevalence of peripheral arterial disease in PBC women and its association with the gut-liver axis and systemic inflammation.

METHODS

Thirty patients affected by PBC and hypercholesterolemia were enrolled, with equal-sized groups of women with non-alcoholic fatty liver disease (NAFLD) and healthy controls (CTRL). All patients underwent Doppler ultrasound examination of peripheral arteries, assessment of flow-mediated dilation, quantification of circulating cytokines and vasoactive mediators and characterization of the gut microbiota.

RESULTS

PBC patients had a higher prevalence of lower extremity arterial disease (LEAD) defined as atherosclerotic plaques in any of femoral, popliteal and/or tibial arteries compared with both NAFLD and CTRL women (83.3% vs. 53.3% and 50%, respectively; p = .01). Factors associated with LEAD at univariate analysis were VCAM-1 (p = .002), ICAM-1 (p = .003), and TNF-alpha (p = .04) serum levels, but only VCAM-1 (OR 1.1, 95% CI 1.0-1.1; p = .04) and TNF-alpha (OR 1.12, 95% CI 0.99-1.26; p = .04) were confirmed as independent predictors in the multivariate model. Gut microbiota analysis revealed that Acidaminococcus (FDR = 0.0008), Bifidobacterium (FDR = 0.001) and Oscillospira (FDR = 0.03) were differentially expressed among groups. Acidaminococcus, which was increased in PBC, was positively correlated with TNF-alpha serum levels. Down-regulation of metabolic pathways linked to fatty acid and butyrate metabolism, glyoxylate metabolism and branched-chain amino acids degradation was found in the functional gut metagenome of PBC women.

CONCLUSIONS

LEAD is common in patients affected by PBC and is associated with inflammatory markers and alterations in the gut-liver axis.

Effects of l-Arginine Plus Vitamin C Supplementation on Physical Performance, Endothelial Function, and Persistent Fatigue in Adults with Long COVID: A Single-Blind Randomized Controlled Trial

Long COVID, a condition characterized by symptom and/or sign persistence following an acute COVID-19 episode, is associated with reduced physical performance and endothelial dysfunction. Supplementation of l-arginine may improve endothelial and muscle function by stimulating nitric oxide synthesis. A single-blind randomized, placebo-controlled trial was conducted in adults aged between 20 and 60 years with persistent fatigue attending a post-acute COVID-19 outpatient clinic. Participants were randomized 1:1 to receive twice-daily orally either a combination of 1.66 g l-arginine plus 500 mg liposomal vitamin C or a placebo for 28 days. The primary outcome was the distance walked on the 6 min walk test. Secondary outcomes were handgrip strength, flow-mediated dilation, and fatigue persistence. Fifty participants were randomized to receive either l-arginine plus vitamin C or a placebo. Forty-six participants (median (interquartile range) age 51 (14), 30 [65%] women), 23 per group, received the intervention to which they were allocated and completed the study. At 28 days, l-arginine plus vitamin C increased the 6 min walk distance (+30 (40.5) m; placebo: +0 (75) m, p = 0.001) and induced a greater improvement in handgrip strength (+3.4 (7.5) kg) compared with the placebo (+1 (6.6) kg, p = 0.03). The flow-mediated dilation was greater in the active group than in the placebo (14.3% (7.3) vs. 9.4% (5.8), p = 0.03). At 28 days, fatigue was reported by two participants in the active group (8.7%) and 21 in the placebo group (80.1%; p < 0.0001). l-arginine plus vitamin C supplementation improved walking performance, muscle strength, endothelial function, and fatigue in adults with long COVID. This supplement may, therefore, be considered to restore physical performance and relieve persistent symptoms in this patient population.

Impaired Endothelial Function in Convalescent Phase of COVID-19: A 3 Month Follow Up Observational Prospective Study

Background: Endothelial dysfunction has a role in acute COVID-19, contributing to systemic inflammatory syndrome, acute respiratory distress syndrome, and vascular events. Evidence regarding COVID-19 middle- and long-term consequences on endothelium are still lacking. Our study aimed to evaluate if COVID-19 severity could significantly affect the endothelial function after three months from the acute phase. Methods: We assessed endothelial function in outpatients with previous COVID-19 three months after negative SARS-CoV-2 molecular test by measuring flow-mediated dilation (FMD) in patients categorized according to a four-variable COVID-19 severity scale (“home care”; “hospital, no oxygen”; “hospital, oxygen”; “hospital requiring high-flow nasal canula, non-invasive ventilation, invasive mechanical ventilation, or extracorporeal membrane oxygenation”). FMD difference among COVID-19 severity categories was assessed with analysis of variance; we further clarified the relationship between FMD and previous COVID-19 severity with multivariate logistic models. Results: Among 658 consecutive COVID-19 subjects, we observed a significant linear trend of FMD reduction with the increase of the COVID-19 category (p < 0.0001). The presence of endothelial dysfunction was more frequent among hospitalized patients (78.3%) with respect to home-care patients (21.7%; p < 0.0001). COVID-19 severity was associated with increased endothelial dysfunction risk (OR: 1.354; 95% CI: 1.06−1.71; p = 0.011) at multivariate binary logistic analysis. FMD showed a significant direct correlation with PaO2 (p = 0.004), P/F ratio (p = 0.004), FEV1 (p = 0.008), and 6MWT (p = 0.0001). Conclusions: Hospitalized COVID-19 subjects showed an impaired endothelial function three months after the acute phase that correlated with pulmonary function impairment. Further studies are needed to evaluate if these subjects are at higher risk of developing pulmonary disease or future cardiovascular events.

Distinctive Role of the Systemic Inflammatory Profile in Non-Small-Cell Lung Cancer Younger and Elderly Patients Treated with a PD-1 Immune Checkpoint Blockade: A Real-World Retrospective Multi-Institutional Analysis

An immune checkpoint blockade with mAbs to PD-1 and PD-L1 is an expanding therapeutic option for mNSCLC patients. This treatment strategy is based on the use of mAbs able to restore the anti-tumor activity of intratumoral T cells inhibited by PD-1 binding to PD-L1/2 on tumor and inflammatory cells. It has been speculated that a chronic status of systemic inflammation as well as the immunosenescence physiologically occurring in elderly patients may affect the efficacy of the treatment and the occurrence of irAEs. We performed a multi-institutional retrospective study aimed at evaluating the effects of these mAbs (nivolumab or atezolizumab) in 117 mNSCLC patients younger (90 cases) and older (27 cases) than 75 years in correlation with multiple inflammatory parameters (NLR, CRP, ESR, LDH and PCT). No differences were observed when the cohorts were compared in terms of the frequency of PFS, OS, inflammatory markers and immune-related adverse events (irAEs). Similarly, the occurrence of irAEs was strictly correlated with a prolonged OS survival in both groups. On the contrary, a negative correlation between the high baseline levels of inflammatory markers and OS could be demonstrated in the younger cohort only. Overall, PD-1/PD-L1-blocking mAbs were equally effective in young and elderly mNSCLC patients; however, the detrimental influence of a systemic inflammation at the baseline was only observed in young patients, suggesting different aging-related inflammation immunoregulative effects.

Improved gut microbiota features after the resolution of SARS‑CoV‑2 infection

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) has a tropism for the gastrointestinal tract and several studies have shown an alteration of the gut microbiota in hospitalized infected patients. However, long-term data on microbiota changes after recovery are lacking.

METHODS

We enrolled 30 patients hospitalized for SARS‑CoV‑2-related pneumonia. Their gut microbiota was analyzed within 48 h from the admission and compared with (1) that of other patients admitted for suspected bacterial pneumonia (control group) (2) that obtained from the same subject 6 months after nasopharyngeal swab negativization.

RESULTS

Gut microbiota alpha-diversity increased 6 months after the resolution of SARS-CoV-2 infection. Bacteroidetes relative abundance was higher (≈ 36.8%) in patients with SARS-CoV-2, and declined to 18.7% when SARS-CoV-2 infection resolved (p  =  0.004). Conversely, Firmicutes were prevalent (≈ 75%) in controls and in samples collected after SARS-CoV-2 infection resolution (p  =  0.001). Ruminococcaceae, Lachnospiraceae and Blautia increased after SARS-CoV-2 infection resolution, rebalancing the gut microbiota composition.

CONCLUSION

SARS-CoV-2 infection is associated with changes in the gut microbiome, which tend to be reversed in long-term period.

Depression and Endothelial Dysfunction in Psoriatic Arthritis: Is There Any Possible Relationship?

Background: Cardiovascular events (CVEs) are the first cause of death in patients with psoriatic arthritis (PsA). Depression is a recognized risk factor in cardiovascular events and is frequently associated with PsA. Flow-mediated dilatation (FMD) is a widely used method for assessing endothelial dysfunction, a parameter with strong prognostic implications for CVEs. The study aims to explore the relationship between FMD, depressive symptoms and serum cytokines in a cohort of patients with PsA. Patients and Methods: FMD was assessed in 50 consecutive PsA patients aged between 30 and 75 years without known cerebrovascular and coronary heart disease or diabetes. Depressive symptoms were reported using the related subscale of the Hospital Anxiety and Depression Scale (HDS). Disease features, activity indexes, and adjusted Framingham risk score (aFRS) were calculated. Serum level of IL-6, TNF-α, and IL-17A were also assessed. Results: In PsA patients (age 50.7 ± 10.2 years, male 42%, disease duration 5.9 ± 3.3 years, Disease Activity in PSoriatic Arthritis (DAPSA) score 14.0 ± 9.4) FMD inversely correlated with the severity of depressive symptoms according to HDS (ρ = -0.339, p = 0.016), age (ρ = -0.507, p = 0.001), aFRS (rs = -0.453, p < 0.001), duration of PsA (ρ = -0.507, p = 0.001), intensity of pain (ρ = -0.507, p = 0.001), and DAPSA (ρ = -0.507, p = 0.001). No statistically significant correlation was found between FMD or HDS and serum cytokines concentrations. HDS predicted FMD in a model adjusted for age, aFRS, PsA duration, and pain intensity (β = -0.271, p = 0.008), with depressive symptoms contributing directly to 6.4% of the variance. Conclusions: Depressive symptoms correlate with endothelial dysfunction with an exposure-response pattern in our cohort of PsA patients.

Conyza bonariensis as an alternative host for Colletotrichum species in Argentina

AIMS

This study investigated the diversity of Colletotrichum isolates recovered from Conyza bonariensis leaves through the use of morphological characteristics, growth rate, carbon sources utilization and phylogenetic analysis.

METHODS AND RESULTS

In all, 30 Colletotrichum isolates recovered from C. bonariensis leaves showing symptoms of disease were included in the present study. Based on the analysis of morphology and sequences, the isolates were distributed into six Colletotrichum species complexes. The concatenated alignment of GAPDH and ITS sequences showed that 20 out of 30 isolates were included in four species complexes which comprise the most important pathogens causing anthracnose in soybean or anthracnose and stalk rot in maize: C. truncatum, C. orchidearum, C. gloeosporioides and C. graminicola. The remaining 10 isolates were included in the C. boninense and C. destructivum species complexes or could not be assigned to any complex with the available information.

CONCLUSION

Weeds belonging to genus Conyza are host to soybean and maize potential pathogenic species of Colletotrichum and could have a role as inoculum reservoir for cross contamination in the agroecosystem.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combined use of morphological, kinetics and physiological parameters of growth and phylogenetic analysis in Colletotrichum isolates from Conyza leaves allowed the detection of species complexes previously not identified in Argentina.

Low molecular weight heparin as cause of liver injury: case report and literature review

Low molecular weight heparins (LMWH) are a class of drugs including various molecules that inhibit predominantly the factor V of coagulation and are used in a wide range of clinical settings for the management of venous thromboembolism and acute coronary syndrome. Despite LMWH are considered safe and associated with a lower incidence of side effects compared to unfractioned heparin, it is worth considering that the use of LWMH can be associated with complications. Some of these, such as bleeding and thrombocytopenia, are well-known, whereas other ones are often underestimated leading to a diagnostic delay. In this case report, we describe a case of a 73-years-old man who recently started nadroparin for deep vein thrombosis presenting with acute hepatitis. The diagnostic workup of drug-induced liver injury (DILI) requires the exclusion of other causative agents and temporal association between the initiation of the culprit drug and hyper aminotransferasemia. This clinical case analyzes how to deal with a suspicion of DILI and consider LWMH as a potential cause of DILI, which requires a modification of the anticoagulant treatment.

Liver involvement is not associated with mortality: results from a large cohort of SARS-CoV-2-positive patients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is frequently associated with liver test abnormalities.

AIMS

To describe the evolution of liver involvement during SARS-CoV-2 infection and its effect on clinical course and mortality.

METHODS

Data of 515 SARS-CoV-2-positive patients were collected at baseline and during follow-up, last evaluation or death. Stratification based on need for hospitalisation, severe disease and admission to intensive care unit (ICU) was performed. The association between liver test abnormalities (baseline and peak values) and ICU admission or death was also explored.

RESULTS

Liver test abnormalities were found in 161 (31.3%) patients. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) were increased in 20.4%, 19% and 13.6% of patients, respectively. Baseline liver test abnormalities were associated with increased risk of ICU admission (OR 2.19 [95% CI 1.24-3.89], P = 0.007) but not with mortality (OR 0.84 [95% CI 0.49-1.41], P = 0.51). Alkaline phosphatase (ALP) peak values were correlated with risk of death (OR 1.007 [95% CI 1.002-1.01], P = 0.005) along with age, multiple comorbidities, acute respiratory distress syndrome, ICU admission and C-reactive protein. Alterations of liver tests worsened within 15 days of hospitalisation; however, in patients with the longest median follow-up, the prevalence of liver test alterations decreased over time, returning to around baseline levels.

CONCLUSIONS

In SARS-CoV-2-positive patients without pre-existing severe chronic liver disease, baseline liver test abnormalities are associated with the risk of ICU admission and tend to normalise over time. The ALP peak value may be predictive of a worse prognosis.

Incidence of deep vein thrombosis among non-ICU patients hospitalized for COVID-19 despite pharmacological thromboprophylaxis

BACKGROUND

A remarkably high incidence of venous thromboembolism (VTE) has been reported among critically ill patients with COVID-19 assisted in the intensive care unit (ICU). However, VTE burden among non-ICU patients hospitalized for COVID-19 that receive guideline-recommended thromboprophylaxis is unknown.

OBJECTIVES

To determine the incidence of VTE among non-ICU patients hospitalized for COVID-19 that receive pharmacological thromboprophylaxis.

METHODS

We performed a systematic screening for the diagnosis of deep vein thrombosis (DVT) by lower limb vein compression ultrasonography (CUS) in consecutive non-ICU patients hospitalized for COVID-19, independent of the presence of signs or symptoms of DVT. All patients were receiving pharmacological thromboprophylaxis with either enoxaparin or fondaparinux.

RESULTS

The population that we screened consisted of 84 consecutive patients, with a mean age of 67.6 ± 13.5 years and a mean Padua Prediction Score of 5.1 ± 1.6. Seventy-two patients (85.7%) had respiratory insufficiency, required oxygen supplementation, and had reduced mobility or were bedridden. In this cohort, we found 10 cases of DVT, with an incidence of 11.9% (95% confidence interval [CI] 4.98-18.82). Of these, 2 were proximal DVT (incidence rate 2.4%, 95% CI -0.87-5.67) and 8 were distal DVT (incidence rate 9.5%, 95% CI 3.23-5.77). Significant differences between subjects with and without DVT were D-dimer > 3000 µg/L (P < .05), current or previous cancer (P < .05), and need of high flow nasal oxygen therapy and/or non-invasive ventilation (P < .01).

CONCLUSIONS

DVT may occur among non-ICU patients hospitalized for COVID-19, despite guideline-recommended thromboprophylaxis.

AB0757 ASSOCIATION BETWEEN DEPRESSIVE SYMPTOMS AND ENDOTHELIAL DYSFUNCTION IN PATIENTS WITH PSORIATIC ARTHRITIS

Background:

Cardiovascular complications are the leading cause of death in patients with psoriatic arthritis (PsA), but current strategies for reducing cardiovascular risk are still inadequate. Depression is a common comorbidity in PsA patients and it is recognized as an independent cardiovascular risk factor in the general population. Endothelial dysfunction, assessed as a reduction in brachial artery Flow Mediated Dilation (FMD), is a predictor of major cardiovascular events in high and low risk populations.

Objectives:

To investigate the relationship between endothelial function and depressive symptoms in a cohort of patients with PsA.

Methods:

Sixty consecutive patients with PsA, aged between 30 and 79 years, with no history of major cardiovascular events, were characterized for traditional cardiovascular risk factors and features of psoriatic disease. The risk of cardiovascular events according to traditional risk factors was calculated using the Framingham Risk Score (FRS) and the presence of depressive symptoms was defined through the Hospital Anxiety and Depression Scale (HDS) using the validated cut-off of 8. Endothelial function was assessed by FMD. Serum IL-6 was quantified by ELISA, IL-17 and TNF-α levels by Luminex method.

Results:

Patients had an average age of 52.1±11.0 years, 43.3% of them were male, 23.3% obese and 25.0% active smokers; 38.3%, 25.0% and 11.7% were treated for high blood pressure, dyslipidemia and diabetes mellitus, respectively. The 10-year risk of major cardiovascular events estimated by FRS was 10.4%. The mean duration of PsA was 9.4 years, 30.0% of patients were in minimal disease activity (MDA) and 61.7% and 46.7% were treated with conventional and biotechnological DMARDs, respectively. The mean HDS value was 6.9±3.2 and 43.4% of patients had significant depressive symptoms. The severity of depressive symptoms according to HDS correlated with disease activity according to DAPSA (r=0.449, p=0.001). The mean FMD was 7.8±3.8%, this value correlated inversely with age (r=-0.408,p<0.001), risk of major cardiovascular events according to FRS (r=-0.327, p=0.011) and severity of depressive symptoms according to HDS (r=-0.285, p=0.027). The correlation between FMD and serum IL-6, IL-17 and TNF-alpha levels was not statistically significant. In multivariate linear regression models, the relationship between FMD and HDS was significant also when corrected for age (β=-0.26, p=0.03, R2=0.23) and FRS normalized through logarithmic transformation (β=-0.32, p=0.009, R2=0.22).

Conclusion:

The degree of endothelial dysfunction quantified by FRS correlates with the severity of the depressive symptoms in patients with PsA, independently of the cardiovascular risk attributable to classical risk factors. The weak relationship between FRS and serum levels of IL-6, IL-17 and TNF-alpha suggests a role of factors independent of inflammation in the regulation of endothelial function in patients with PsA. Systematic research and treatment of depressive symptoms could contribute to a more complete stratification and a better management of cardiovascular risk in patients with PsA.

Disclosure of Interests:

Enrico De Lorenzis: None declared, Angela Di Giorgio: None declared, Gerlando Natalello: None declared, Antonio Nesci: None declared, Dario Bruno: None declared, Donatella Lucchetti: None declared, Giacomo Tanti: None declared, Clara Di Mario: None declared, Pietro Rubortone: None declared, Maria Rosaria Magurano: None declared, Barbara Tolusso: None declared, Angelo Santoliquido: None declared, Giusy Peluso: 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

Association between peripheral arterial disease and cardiovascular risk factors: role of ultrasonography versus ankle-brachial index

OBJECTIVE

Most studies on atherosclerotic processes include peripheral arterial disease diagnosis only if patients report symptoms suggestive of peripheral arterial disease and/or an instrumental demonstration of lower limbs perfusion deficit is provided, rather than the sole presence of atherosclerotic lesions localized at lower limbs, this attitude leading to ignore early stages of the disease. To overcome these limitations, we have proposed a new ultrasonographic semiquantitative score to better identify all disease stages. The aim of this study is to compare ultrasonography versus ankle-brachial index in the association between peripheral arterial disease and cardiovascular risk factors.

PATIENTS AND METHODS

This cross-sectional observational study included subjects undergoing lower limbs evaluation through ultrasonography and ankle-brachial index determination because of symptoms suggestive of peripheral arterial disease or presence of known cardiovascular risk factors. Associations between ultrasonography and ankle-brachial index with cardiovascular risk factors were assessed by first fitting logistic regression models and then comparing the respective areas under the Receiver Operating Characteristic and 95% confidence intervals.

RESULTS

The areas under the Receiver Operating Characteristic for each cardiovascular risk factors were consistently larger in magnitude for ultrasonography compared with ankle-brachial index, this comparison being statistically significant for age, male gender, smoking status, hypertension, diabetes mellitus and previous cardiovascular events.

CONCLUSIONS

Our study demonstrates that ultrasonography is a better method to screen peripheral arterial disease respect to ankle-brachial index in order to identify all disease stages. These findings are useful in particular when including peripheral arterial disease as organ damage marker in cardiovascular risk stratification.

Subclinical atherosclerosis and endothelial dysfunction in patients with polymyalgia rheumatica: a pilot study

Objective: The aim of the study was to investigate endothelial function in treatment-naïve polymyalgia rheumatica (PMR) patients and its modification during steroid therapy, in relation to changes in clinical and laboratory parameters.Method: This prospective observational study involved patients with a new diagnosis of PMR according to provisional American College of Rheumatology/European League Against Rheumatism 2012 criteria, who were naïve to steroid therapy, and control subjects matched for age, gender, and comorbidities. All participants underwent clinical and vascular ultrasound evaluations at baseline and after 1, 3, 6, and 12 months of steroid therapy. For the study of endothelial function, we evaluated the brachial artery reactivity, which has emerged as the most well-established technique used in adults, by assessing flow-mediated dilatation (FMD), which measures the endothelium-dependent vasodilatation.Results: Sixteen newly diagnosed PMR patients were compared with a population of 16 matched controls. FMD values in all subjects showed an inverse correlation with the values of erythrocyte sedimentation rate and C-reactive protein. At baseline, the FMD of PMR patients was significantly lower than controls and remained significantly lower with respect to controls until the sixth month of therapy, despite a clinical improvement already being evident after 1 month of therapy.Conclusions: PMR is characterized by an important chronic subclinical inflammatory component. This pilot study demonstrates that affected patients show endothelial dysfunction that slowly responds to steroid therapy. Further studies are needed to investigate the clinical relevance of these observations and, in particular, to monitor the cardiovascular risk profile of PMR patients.

Evaluation of long term survival in pretreated metastatic colorectal cancer patients undergoing GOLFIG chemoimmunotherapy regimen

e15057

Background: In the last few years, there has been a renewed interest on the potential use of immunotherapy alone or combined to chemotherapy (CHT) for mCRC patients. GOLFIG regimen (biweekly Gemcitabine+FOLFOX and IL2 and GM-CSF) was designed to enhance immunomodulating effects of selected cytotoxic drugs by combining them with cytokines able to promote priming and effector phases of the immune-response. This regimen has been tested in two different phase II and III clinical trials in mCRC patients, whose successful results have been published. Here we present the results a retrospective analyses including all the patients treated in a period of 16 years. Methods: This is a multi-institutional retrospective study including 179 mCRC patients (106 men, 73 women). They received a median of 12 courses of GOLFIG regimen (treated between June 2002 and November 2018). K-RAS mutational status has also been evaluated in 74 pts (41 wild type and 33 mutated); as for sidedness 112 pts had a left disease and 67 pts right disease; 71 pts received only one previous CHT line and 100 more than two lines. PFS and OS were evaluated by Kaplan-Meier curves and Cox-regression analyses in different subgroups (RAS mutational status, sidedness, previous CHT lines) to estimate their effect on survival endpoints. Results: We recorded a mean PFS and OS of 15,28 [95%CI:10,36-20,20] and 24,61 [95%CI:19,07-30,14] months, respectively, with no difference in efficacy outcomes observed among the different subgroups (one vs. more than one previous CHT lines; left vs. right primary side; k-ras status mutated vs. wt). Finally, we recorded a 2, 5 and 10 year OS-rate, in 42, 17 and 14 percent of the patients, respectively. The occurrence of self-limiting autoimmunity was confirmed as highly predictive of longer survival. Conclusions: These results confirm that GOLFIG regimen has strong efficacy in mCRC pts and may represent a reliable option in pretreated setting without evident effect of known prognostic variants. Such data offer a strong basis for future clinical trials in mCRC patients, where GOLFIG may represent a scaffold for combinatory immunotherapy approaches with immune-checkpoint blocking drugs.

Development of a third-generation biosensor to determine sterigmatocystin mycotoxin: An early warning system to detect aflatoxin B1

A third-generation enzymatic biosensor was developed to quantify sterigmatocystin (STEH). It was based on a glassy carbon electrode modified with a composite of the soybean peroxidase enzyme (SPE) and chemically reduced graphene oxide. The optimal conditions to construct the biosensor were obtained through an experimental design based on the response surfaces methodology. The experiments were performed in 0.1 mol L-1 phosphate buffer solution, pH 5. Amperometric measurements were carried out at - 0.09 V vs Ag/AgCl (3 mol L-1 NaCl). The biosensor showed a lineal response in the concentration range from 6.9 × 10-9 to 5.0 × 10-7 mol L-1. The limit of detection was 2.3 × 10-9 mol L-1 for a signal: noise ratio of 3: 1. Values of the apparent Michaellis-Menten constant, KMapp, obtained by using both Lineweaver-Burk and Eadi-Hofstee methods were (1.5 ± 0.2) × 10-6 and (1.2 ± 0.2) × 10-6 mol L-1, respectively. STEH was analyzed in corn samples spiked with STEH, with an average recovery of 96.5%. The biosensor was also used to determine STEH in corn samples inoculated with the Aspergillus flavus fungus, which is an aflatoxins producer. Considering that STEH is a precursor of aflatoxin B1 (AFB1) in its biological transformation, its decrease over time was related to the production of AFB1. The STEH concentration determined using the biosensor was in very good agreement with that determined by HPLC.

Influence of crop residues, matric potential and temperature on growth of Exserohilum turcicum an emerging maize pathogen in Argentina

Northern corn leaf blight (NCLB) caused by Exserohilum turcicum is an endemic foliar disease in the Argentinean maize production area. Before applying a control method, it is essential to focus on factors that lead to the survival and conservation of E. turcicum inoculum. However, there is little information about the life cycle of this emerging pathogen in our country. The objective of the present work was to analyse the growth ability of three E. turcicum isolates under different type and conditions of maize, wheat and soybean residues, matric potential, temperature and their interactions. Statistical analysis demonstrated a significant effect of three factors on growth rate: residues-based media, matric potential and temperature. Among them the major effect was produced by matric potential followed by temperature. Although there were no significant differences in the growth rate among different residues types, the range of conditions in which growth occurred was different. According to these results, soybean residues would allow a better survival of E. turcicum inoculum under no-tillage system and providing an inoculum source for maize infections in subsequent year. SIGNIFICANCE AND IMPACT OF THE STUDY: Exserohilum turcicum is an emerging pathogen in Argentina that has caused significant economic losses in different maize growing areas. However, at present there is a lack of information about the life cycle of this fungal pathogen. The present study shows the influence of abiotic factors such as temperature and water potential on the growth of E. turcicum on different crop residues used in rotations with maize under no-till system cultivation. According to our results, soybean residues allowed the pathogen growth in a wider range of conditions compared to wheat and maize residue, providing an inoculum source for maize infections in subsequent season.

A novel ultrasound-based vascular calcification score (CALCS) to detect subclinical atherosclerosis

OBJECTIVE

To quantify non-coronary vascular calcifications (VC) in asymptomatic patients at low-intermediate cardiovascular risk by a new color Doppler ultrasound (DUS)-based score (the carotid, aortic, lower limbs calcium score, CALCs), and to correlate this score with classical parameters associated with cardiovascular risk [carotid intima media thickness (IMT), and arterial stiffness (AS)].

PATIENTS AND METHODS

All consecutive asymptomatic patients who underwent a screening DUS of non-coronary circulation were evaluated and patients at low-intermediate cardiovascular risk were selected according to Framingham risk score (FRS). Among them, we enrolled 70 patients with US evidence of VC and 71 age, sex and FRS matched controls. The presence of VC was correlated with classical markers of cardiovascular risk, such as AS and intima-media thickness (IMT). AS, expressed as pulse wave velocity (PWV) and arterial distensibility, carotid IMT and CALCs were measured for both groups. AS and c-IMT were assessed by a new Radio-Frequency (RF) DUS-based method. CALCs was generated by our previously described B-mode DUS-based method according to number/size of VC in 11 non-coronary segments (range 0-33).

RESULTS

Patients with VC presented higher AS and IMT values than controls (PWV 8.34±0.98 m/s vs. 6.74±0.68 m/s, p<0.0001; arterial distensibility 267±12 mm vs. 315±65 mm, p=0.001; IMT 687±132 mm vs. 572±91 mm, p<0.0001). Mean CALCs of patients with VC was 8.41±7.78. CALCs were significantly correlated with c-IMT (p<0.0001; r=0.3), PWV (p<0.0001; r=0.4) and arterial distensibility (p=0.002; r=-0.1).

CONCLUSIONS

DUS-based CALCs is highly correlated with other validated markers of subclinical atherosclerosis, such as c-IMT and AS. Our results demonstrated the ability of CALCs to identify individual predictive factors beyond the traditional risk factors by quantifying an interesting and novel step of the atherogenic process. Future studies on larger series and with adequate follow up are necessary to confirm these results and to evaluate the role of this new marker in monitoring calcific atherosclerosis progression.

New semiquantitative ultrasonographic score for peripheral arterial disease assessment and its association with cardiovascular risk factors

The data concerning the distribution, extent and progression of peripheral arterial disease (PAD), as well as its association with traditional cardiovascular (CV) risk factors, have generally been obtained from studies of patients in advanced stages of the disease undergoing surgical or endovascular treatment. In this study, we have introduced a new semiquantitative ultrasonographic score (ultrasonographic lower limb atherosclerosis (ULLA) score) that is able to categorize lower limb atherosclerotic lesions at all stages of PAD. We then associated these ultrasonographic categories with a CV risk profile. We enrolled 320 consecutive subjects with symptoms suggestive of PAD or with known CV risk factors referring to our angiology unit between 1 July 2014 and 30 June 2015 for ultrasonographic evaluation of the lower limb arteries. Femoropopliteal and run-off segments were categorized together and separately based on their ultrasonographic characteristics. In univariate and multivariate analyses, the ULLA scores were significantly associated with the main CV risk factors, that is, age, male gender, cigarette smoking, arterial hypertension, diabetes, dyslipidemia, sedentary lifestyle, previous CV events and family history of CV disease, and also confirming the specific association of single risk factors with different segments of lower limb arteries. The proposed ULLA score enables a complete evaluation of the entire lower limb atherosclerotic burden, extending the results concerning the association of PAD with CV risk factors to all stages of the disease, including the early stages. It can be feasible that this new score will facilitate better evaluation of the progression of PAD and its prospective role in CV risk stratification.

New modalities of ultrasound-based intima-media thickness, arterial stiffness and non-coronary vascular calcifications detection to assess cardiovascular risk

BACKGROUND

Carotid intima-media thickness (c-IMT), arterial stiffness (AS) and vascular calcification (VC) are now considered important new markers of atherosclerosis and have been associated with increased prevalence of cardiovascular events. An accurate, reproducible and easy detection of these parameters could increase the prognostic value of the traditional cardiovascular risk factors in many subjects at low and intermediate risk. Today, c-IMT and AS can be measured by ultrasound, while cardiac computed tomography is the gold standard to quantify coronary VC, although concern about the reproducibility of the former and the safety of the latter have been raised. Nevertheless, a safe and reliable method to quantify non-coronary (i.e., peripheral) VC has not been detected yet.

AIM

To review the most innovative and accurate ultrasound-based modalities of c-IMT and AS detection and to describe a novel UltraSound-Based Carotid, Aortic and Lower limbs Calcification Score (USB-CALCs, simply named CALC), allowing to quantify peripheral calcifications. Finally, to propose a system for cardiovascular risk reclassification derived from the global evaluation of "Quality Intima-Media Thickness", "Quality Arterial Stiffness", and "CALC score" in addition to the Framingham score.

Biomarkers of low-grade inflammation in primary varicose veins of the lower limbs

OBJECTIVE

To analyze serum biomarkers of CVD in selected patients with primary axial reflux of great saphenous vein in one or both lower limbs.

PATIENTS AND METHODS

Ninety-six patients affected by uncomplicated varicose veins, were enrolled in the study. A unilateral, primary axial reflux in great saphenous veins was detected in 54 patients (U-CVD group) and a bilateral one in 42 (B-CVD group). Sixty-five age and sex-matched subjects without venous reflux were enrolled as controls. Mean venous pressure of both lower limbs at the distal great saphenous vein (mGSVP) and venous reflux were measured by continuous-wave Doppler ultrasound and echoduplex scanning, respectively. Reactive Oxygen Species (ROS), tissue Plasminogen Activator (t-PA) and its Inhibitor 1 (PAI-1) activities, Hematocrit (HTC), White Blood Cells (WBC), Neutrophyls (NEU), Platelets (PLT), Fibrinogen (FIB) and Blood Viscosity (BV) were assessed in blood samples drawn from the antecubital vein.

RESULTS

B-CVD group showed higher fibrinogen values (p < 0.005) and higher mean venous pressure (0 < 0.0001) in comparison to controls, while U-CVD did not. No difference was found between both groups and controls for all the other parameters.

CONCLUSIONS

Increased fibrinogen levels in patients with bilateral varicose veins may represent an early warning signal, as it could be associated to the long-term progression of chronic venous disease.

Kinetic and mechanistic aspects of sensitized photodegradation of β-lactam antibiotics: microbiological implications

Amoxicillin (Amx) and cephalexin (Cfx) are β-lactam antibiotics widely used in human and veterinary medicine. Two points of interest surrounding these molecules are the photodegradation of the molecules and their microbiological implications, as well as the persistence and bioaccumulation in the environment which may cause resistance to bacterial strains. The kinetic and mechanistic aspects of the photosensitized degradation of Amx and Cfx have been studied in water at pH 7.4 and 10 by stationary and time-resolved methods. Kinetic evidence indicates that the Rose Bengal-sensitized photooxidation of Amx at pH 7.4 proceeds via O(2)((1)Δ(g)) and O(2•-) mechanisms while at pH 10 the degradation path occurs, principally, via O(2)((1)Δ(g)). For Cfx, this process is attributed to O(2)((1)Δ(g)) and O(2•-). Photoproducts, which arise from the addition of oxygen atoms and subsequent oxidation of the groups -CH(3) to -COOH, were detected. For both antibiotics the bacteriostatic activity decreases in parallel to their photodegradation. The results of this study could potentially help scientists to better understand and predict the photodegradability of these antibiotics on living organisms and in different environmental compartments.

Ghrelin system in alcohol-dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving

Animal studies suggest that the gut-brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics. This investigation consisted of two studies. Study 1 was a 12-week study with alcohol-dependent subjects, where plasma ghrelin determinations were assessed four times (T0-T3) and related to alcohol intake and craving [Penn Alcohol Craving Score (PACS) and Obsessive Compulsive Drinking Scale (OCDS)]. Serum growth hormone levels and assessment of the nutritional/metabolic status were also performed. Study 2 was a pilot case-control study to assess ghrelin gene polymorphisms (Arg51Gln and Leu72Met) in alcohol-dependent individuals. Study 1 showed no significant differences in ghrelin levels in the whole sample, while there was a statistical difference for ghrelin between non-abstinent and abstinent subjects. Baseline ghrelin levels were significantly and positively correlated with the PACS score at T1 and with all craving scores both at T2 and T3 (PACS, OCDS, obsessive and compulsive OCDS subscores). In Study 2, although there was a higher frequency of the Leu72Met ghrelin gene polymorphism in alcohol-dependent individuals, the distribution between healthy controls and alcohol dependent individuals was not statistically significant. This investigation suggests that ghrelin is potentially able to affect alcohol-seeking behaviors, such as alcohol drinking and craving, representing a new potential neuropharmacological target for AD.

Natural maize phytochemicals for control of maize mycoflora and aflatoxigenic fungi

This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) alone at concentrations of 20 and 25 mM, ferulic acid (FA) at concentration of 30 mM and two mixtures, CA-FA (20+30 mM) and CA-FA (25+30 mM) on natural maize mycoflora, Aspergillus section Flavi population and aflatoxin B1 production. These studies were carried out in maize grain in relation to a water activity of 0.99, 0.97 and 0.94. CA at 25 mM and the mixture CA-FA (25+30 mM) were the most effective treatments at inhibiting natural maize mycoflora at all aw assayed after 11 and 35 days of incubation at 25 °C. In general, 20 mM CA caused complete inhibition of Aspergillus section Flavi population at all aw values tested during all incubation period without an additional inoculum. 20 mM CA and 25 mM CA showed the major inhibitory effect on aflatoxin B1 accumulation of control and Aspergillus section Flavi additionally inoculated during all incubation periods. The data showed that CA and FA could be considered as effective fungitoxicants for natural maize mycoflora and aflatoxigenic fungi in the aw range 0.99 to 0.94. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize.

Impact of two bacterial biocontrol agents on bacterial and fungal culturable groups associated with the roots of field-grown maize

AIMS

To assess the impact of Bacillus amyloliquefaciens and Microbacterium oleovorans on bacterial and fungal groups associated to the roots of field-grown maize.

METHODS AND RESULTS

Identification and count of bacterial and fungal culturable populations associated to the roots of maize seedlings, changes in culturable community structure according to the richness and diversity indexes concept and shifts in microbial activity through analysis of cellulolytic, ammonification and nitrification potentials were determined, in relation to kernel treatment with biological control agents. Following the treatment of maize kernels with B. amyloliquefaciens at 10(7) CFU ml(-1), an increase in bacterial diversity was observed at the rhizoplane of resultant seedlings. Bacterial richness was significantly increased at the root inner tissues of seedlings treated with Mic. oleovorans. Fusarium, Aspergillus, Penicillium and Trichoderma were the main fungal genera isolated and there population sizes were unequally affected by the addition of biocontrol agents.

CONCLUSIONS

Numbers and types of isolated bacteria and fungi changed in response to the addition of biocontrol agents, while microbial activity remained unchanged with respect to control.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides an insight of the effects of proven biocontrol agents on micro-organisms naturally associated to the target crop.

Affective and psychiatric disorders in celiac disease

Several extraintestinal clinical manifestations have been reported in celiac disease (CD). Among them, growing evidence suggests the association between CD and affective and psychiatric disorders. In this review the most frequent affective and psychiatric disorders associated with CD and the possible mechanisms involved in these associations were analyzed. The available data suggest that screening for CD in patients with affective and/or psychiatric symptoms may be useful since these disorders could be the expression of an organic disease rather than primary psychiatric illnesses.

Interrelation of growth media and water activity in sclerotia characteristics of Aspergillus section Flavi

AIMS

To examine sclerotium characteristics of two Aspergillus flavus and two A. parasiticus strains at different growth media and water stress.

METHODS AND RESULTS

The effects of growth media and water activity (0.999, 0.971, 0.955 and 0.937) on characteristics of sclerotia production (number, size and volume) of four isolates of Aspergillus section Flavi were examined. There was total inhibition under the driest conditions (0.955 and 0.937). When an osmotic potential of 0.971 was generated in Czapek agar (CD) and maize meal extract agar with sucrose and sodium nitrate (MMEA S/N), an increase in sclerotial size and volume was observed. The amount of sclerotia produced by cultures at 0.999 a(w) value was higher on CD.

CONCLUSIONS

The data show that the sclerotia characteristics of A. flavus and A. parasiticus have been influenced by water availability and growth media composition.

SIGNIFICANCE AND IMPACT OF THE STUDY

The information obtained shows that if we know the nutritional and water stress requirements for sclerotia production, it could be possible to develop effective prevention strategies to inhibit the survival of these fungi in grain.

Osmotic and matric potential effects on growth, sugar alcohol and sugar accumulation by Aspergillus section Flavi strains from Argentina

AIMS

The effect of osmotic and matric potential stress on growth and sugar alcohols (polyols: glycerol, erythritol, arabitol and mannitol) and sugars (trehalose and glucose) accumulation in toxigenic and nontoxigenic colonies of Aspergillus flavus and A. parasiticus was evaluated.

METHODS AND RESULTS

Growth of Aspergillus section Flavi with significant reductions at 20 and 30 degrees C was more sensitive to changes in matric potential, between 60 and 100% in the range of -7 to -14 MPa. No significant differences were found between toxigenic and nontoxigenic strains for both species. Total polyol accumulation in unamended maize meal agar medium (-0.75 MPa water potential) was higher at 30 than 20 degrees C. The major change in concentrations of endogenous sugars and total polyols was in matrically amended medium (with PEG 8000) at -7 and -10 MPa. Accumulation of glucose, arabitol, mannitol and erythritol content of A. flavus and A. parasiticus mycelial colonies was greater in normal unstressed maize meal agar medium (-0.75 Mpa) at 20 degrees C. This was modified by solute and matric stress.

CONCLUSIONS

The data showed relative sensitivity to osmotic and matric potential, and temperature, and the impact on growth rates, polyol and sugar accumulation in mycelia of A. flavus and A. parasiticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The matric potential effects on growth may be of particular importance for growth and survival in environments with low-matric potential stress. The tolerance of spoilage fungi such as Aspergillus section Flavi to such modifications could increase the potential for spoilage and mycotoxin production in such substrates. This knowledge is important for understanding the relative ecological fitness of these aflatoxigenic species and in the development of prevention strategies for their control.

In vitro studies on the potential for biological control on Aspergillus section Flavi by Kluyveromyces spp

AIMS

Antagonist activity of Kluyveromyces spp. isolates on Aspergillus section Flavi was studied.

METHODS AND RESULTS

The screening of isolates were made through studies of growth at different water activities and temperatures, index of dominance (I(D)), ecological similarity, antifungal activity and impact on aflatoxin B1 accumulation. High optical density was obtained at 25 and 30 degrees C and 48 h of incubation. Cell growth decreases with decrease in water activity. The predominant interaction was mutual intermingling at a(w) = 0.982 and 0.955, while at a(w) = 0.999 and 0.937 mutual inhibition for contact was exhibited. All isolates were catabolically identical to Aspergillus section Flavi and compete by nutritional source. At high water activities yeasts showed inhibitory activity on Aspergillus strains, inhibition percentages varied between 75 and 100%. The isolates Y9, Y14, Y16, Y22, Y25 and Y33 showed antifungal activity and inhibitory activity on aflatoxin B1 accumulation at all water activities assayed from all Aspergillus section Flavi strains.

CONCLUSIONS

The data show that the isolates selected in a wide range of environmental conditions could exert their roll like biological control agents for Aspergillus section Flavi in storage maize ecosystem.

SIGNIFICANCE AND IMPACT OF THE STUDY

Isolates of Kluyveromyces spp. may have practical value in the postharvest control of storage maize.

Control of Aspergillus growth and aflatoxin production using antioxidants at different conditions of water activity and pH

AIMS

The effect of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trihydroxybutyrophenone (THB) and propyl paraben (PP) (at concentrations of 1, 10 and 20 mmol l(-1)) on germination, growth and aflatoxin B1 production by Aspergillus section Flavi was evaluated.

METHODS AND RESULTS

Studies on the percentage of spore germination, elongation rate, growth rate and aflatoxin B1 production were carried out in vitro in relation to water activity (aw) at 0.982, 0.937, 0.809 and 0.747 values. At 0.809 and 0.747aw values none of the isolates was able to germinate. Overall, PP and BHA were the antioxidants most effective at inhibiting germination of both species. In the presence of the lowest concentration of BHA and PP (1 mmol l(-1)) the conidial germination percentage ranged from 2 to 19% after 15 h of incubation at the highest water activity tested. BHA and PP at 10-20 mmol l(-1) completely inhibited conidial germination. The antioxidants more efficient in controlling Aspergillus elongation rate were PP, BHT and BHA. All strains were much more sensitive to all antioxidants tested on the percentage of spore germination and growth rate at 0.937aw. The antioxidants PP and BHA completely inhibited aflatoxin B1 production by all strains when added at 1 mmol l(-1). Decreased aflatoxin B1 levels in comparison with the control, were observed with BHT at 1, 10 and 20 mmol(-1) with the strain T20 at 0.982aw. In contrast, stimulation was observed with the antioxidant THB at 10 and 20 mmol l(-1) at 0.937aw with the strains T20 and T23. The effect of BHA and PP at 1 mmol l(-1) on lag phase and growth rate was maintained in the pH range between 6 and 8. At all pH values the inhibitory effect of BHA was higher than PP. No aflatoxin B1 was detected at all pH values.

CONCLUSIONS

The data show that BHA and PP could be considered as effective fungitoxicants for A. flavus and A. parasiticus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The information obtained show promise for controlling growth and aflatoxin B1 in stored maize. Futher studies should be carried out to examine the potential for antioxidants, such as BHA and PP to effectively control both growth and aflatoxin production.

Aspergillus section Flavi populations from field maize in Argentina

AIMS

Populations of Aspergillus section Flavi were studied from a commercial field of maize in Río Cuarto, Córdoba, Argentina.

METHODS AND RESULTS

The Aspergillus species were isolated from soil, debris and insects during three periods: pre-planting, growing maize and post-harvest. The colony count from non-rhizospheric soil in the pre-planting period was higher than in growing maize and the post-harvest period. Debris samples analysed during all periods showed similar infection percentages for Aspergillus section Flavi. The samples of insects collected during the maize-growing period showed a lower percentage of Aspergillus isolates than the samples from soil and debris. Aflatoxigenic strains were present in lower levels in each component of the agroecosystem studied. All the strains that produced sclerotia were L strains.

CONCLUSIONS

In this field agroecosystem, the only strains with a high probability for transfer to the storage agroecosystem were L strains with low toxigenic potential.

SIGNIFICANCE AND IMPACT OF THE STUDY

Maize pre-harvest contamination with aflatoxigenic inoculum was not significant.

Aflatoxin B1 and fumosin B1 in mixed cultures of Aspergillus flavus and Fusarium proliferatum on maize

Production of aflatoxin B1 and fumonisin B1 in pure and mixed cultures of Aspergillus flavus and Fusarium proliferatum were determined on irradiated maize seeds inoculated with different spore concentrations at 0.97 water activity (a(w)) and a temperature of 25 degrees C. The highest levels of aflatoxin B1 were produced by A. flavus at the lowest levels of inoculum (10(3) spore ml(-1)). There was no spore concentration influence on fumonisin B1 production after 10, 20 and 35 days of incubation. When A. flavus was co-inoculated with F. proliferatum, aflatoxin B1 production was inhibited. The higher the inocula levels of Fusarium produced, the higher the inhibition and this inhibition increased during the incubation period. Total inhibition was reached at 35 days of incubation. There was no interaction influence on fumonisin B1 production at all inoculum levels assayed. These results suggest that under optimal environmental conditions of substrate, water activity and temperature, the interaction between A. flavus and F proliferatum could produce inhibition of aflatoxin B1 and stimulation of fumonisin B1.

Quantitative amplitude and phase measurement by use of a heterodyne scanning near-field optical microscope

A coherent photon scanning tunneling microscope is presented. The setup employs heterodyne interferometry, allowing both the phase and the amplitude of the optical near field to be measured. Experimental results of measurements on a standing evanescent wave reveal the high resolution that is obtainable with such an approach. In fact we have measured the amplitude and the phase of the near field, with a resolution of 1.6 nm between sample points.

A unique type I keratin intermediate filament gene family is abundantly expressed in the inner root sheaths of sheep and human hair follicles

A unique type I keratin intermediate filament group, comprising three highly related proteins and expressed in the inner root sheath of hair follicles, has been identified in both sheep and human. The first members from these species are named oIRSa1 and hIRSa1 and each encodes a protein of 450 amino acids, with compositional characteristics intermediate between those of previously described hair keratin and epidermal cytokeratin type I intermediate filaments. Detection of abundant mRNA transcripts derived from the sheep and human genes by cRNA in situ hybridization only in the inner root sheath and not in the medulla concurs with the findings of earlier ultrastructural analyses that have reported intermediate filaments only in the inner root sheath. Clustering of the IRSa keratin genes is apparent in the genomes of both species. The three hIRSa genes, known to reside on human chromosome 17, are closely linked to three further type I keratin intermediate filament genes of unknown function. This new gene complex, contained almost entirely within a 156 kb BAC (hRPK.142_H_19), is likely to lie near the type I intermediate filament cytokeratin and hair keratin gene loci at 17q12-q21. A phylogenetic analysis including all known human type I intermediate filament cytokeratins, hHa keratins, hIRSa, and hIRSa-linked keratins suggests that origin of the IRSa keratin intermediate filament linkage group preceded origin of most of the epidermal cytokeratins and all hair keratins during emergence of the keratin intermediate filament genes.

Expression of the homeobox gene, Barx2, in wool follicle development

We have cloned ovine Barx2, a member of the Bar class of homeobox genes, and present the first description of Barx2 expression in wool follicle development. Barx2 is uniformly expressed in the embryonic ectoderm but is transiently downregulated during the initiation of follicle morphogenesis. Subsequently, Barx2 is expressed throughout the epithelial component of the developing follicle except for a small group of cells at the leading edge of the follicle placode. These Barx2-negative cells are destined to form the follicle bulb and are the progenitors of the inner root sheath and hair shaft. In adult follicles, Barx2 is expressed throughout the outer root sheath but not in the inner root sheath or hair shaft, or in dermal cells associated with the follicle. The pattern of Barx2 expression in follicle morphogenesis is similar to that of the cell adhesion molecule E-cadherin, a similarity that echoes Barx2 coexpression with the L1 cell adhesion molecule in other tissues during mouse embryogenesis. Barx2 is also expressed in tongue and esophagus, two other keratinizing tissues, and we speculate that Barx2 may have a general function in controlling adhesive processes in keratinizing epithelia.

Occurrence of Aspergillus section flavi and aflatoxin B1 in corn genotypes and corn meal in Argentina

A study has been carried out in Argentina on samples of corn genotypes from a breeding station as well as in commercially available corn meal. All samples were analyzed for fungal infection and aflatoxin B1. Mycological analysis of corn genotypes showed the presence of three principal genera of filamentous fungi Fusarium (100%), Penicillium (67%) and Aspergillus (60%). In the genus Fusarium three species were identified, F. moniliforme (42%), F. nygamai (56%) and F. proliferatum (1.8%). Eight species of Penicillium were identified, the predominant species isolated were P. minioluteum, P. funiculosum and P. variabile. In the genus ranked third in isolation frequency, two species were identified, A. flavus and A. parasiticus, the percentage of infection was 78% and 21%, respectively. Only one corn genotype was contaminated with aflatoxin B1 at a level of 5 ppb. The corn meal samples showed great differences in fungal contamination, the values ranging from 1 x 10(1) to 7 x 10(5) cfu g-1. Fusarium (68%), Aspergillus (35%) and Penicillium (21%) were the most frequent genera isolated. Among the genus, Aspergillus, A. parasiticus (38%) was the most frequent species isolated. All the samples of corn meal were negative to aflatoxin B1. These results indicate a low degree of human exposure to aflatoxins in Argentina through the ingestion of maize or corn meal.

Transsulfuration, protein synthesis rate and follicle mRNA in the skin of young Merino lambs in response to infusions of methionine and serine

Methionine (Met) is usually the first limiting amino acid for sheep and supplements of Met may increase production of wool and meat. The wool response may be due to an increased supply of cysteine (Cys) from transsulfuration (TS) of Met. Met is catabolized through homocysteine to form Cys when the S from Met is transferred to serine (Ser). We hypothesized that providing additional Met would create a deficiency of Ser and that by simultaneously providing Met and Ser, TS and wool growth could be increased more than by providing Met alone. The effects of i.v. infusions of Met and Ser to young Merino lambs on TS, fractional synthesis rate (FSR) of protein in skin, follicle mRNA and wool growth were examined. Following 4 d of constant i.v. infusion of 3 g Met/d, or 10 g Ser/d or both, the isotope tracers: L-[3-(13)C]Cys, L-[ring-d5]phenylalanine (Phe) and L-[2,3,3-d3]Ser were infused over 8 h to allow for measurements of irreversible loss rate (ILR), and TS in whole body and skin. Skin biopsies were taken for measurement of FSR. Wool growth rate was measured using autoradiography. An infusion of Met significantly (P < 0.05) improved wool growth rate and increased skin FSR, Cys supply from TS and enhanced levels of follicle mRNA (from the K2.10 intermediate filament gene and three gene families encoding keratin associated proteins KAP1, KAP4 and KAP12). The extra Met lowered Ser ILR. The infusion of Ser doubled Ser ILR in the body and increased skin FSR calculated using the Cys tracer in plasma (P < 0.05). However, there were no significant (P > 0.05) changes in TS, skin FSR calculated using the Phe and Ser tracers, follicle mRNA or wool growth rate as a result of Ser infusion. While there were trends towards increased TS and FSR with Ser infusion, the overall lack of significant changes indicates a high capacity for the de novo synthesis of Ser.

Dynamic expression of ornithine decarboxylase in hair growth

Ornithine decarboxylase (ODC) is the key enzyme in the synthesis of polyamines, small cationic molecules believed to have a role in many cellular processes such as cell migration, proliferation and differentiation. We show that ODC expression is associated with cell proliferation and commitment in hair follicle development and hair growth. In embryonic epidermis, ODC is expressed in ectodermal cells at sites where follicles develop, and persists in cells at the leading edge of the follicle placode. ODC is abundantly expressed in proliferating bulb cells of anagen follicles, except for a pocket of cells at the base of the bulb. Entry of the follicle into catagen is accompanied by a down-regulation of ODC expression, which is not resumed until a new follicle is initiated. In vibrissae, ODC expression is more complex. ODC is expressed not only in the bulb but also in the hair shaft, presenting a striking biphasic pattern. Additionally, ODC is expressed in a group of outer root sheath cells in the vicinity of the follicle bulge, the putative site of hair follicle stem cells.

The Notch signalling pathway in hair growth

The Notch signalling pathway is an important mediator of cell fate selection whose involvement in epidermal appendage formation is now becoming recognised. Hair follicle development and hair formation involve the co-ordinated differentiation of several different cell types in which Notch appears to have a role. We report intricate expression patterns for the Notch-1 receptor and three ligands, Delta-1, Jagged-1 and Jagged-2 in the hair follicle. Notch-1 is expressed in ectodermal-derived cells of the follicle, in the inner cells of the embryonic placode and the follicle bulb, and in the suprabasal cells of the mature outer root sheath. Delta-1 is only expressed during embryonic follicle development and is exclusive to the mesenchymal cells of the pre-papilla located beneath the follicle placode. Expression of Jagged-1 or Jagged-2 overlaps Notch-1 expression at all stages. In mature follicles, Jagged-1 and Jagged-2 are expressed in complementary patterns in the follicle bulb and outer root sheath, Jagged-1 in suprabasal cells and Jagged-2 predominantly in basal cells. In the follicle bulb, Jagged-2 is localised to the inner (basal) bulb cells next to the dermal papilla which do not express Notch-1, whereas Jagged-1 expression in the upper follicle bulb overlaps Notch-1 expression and correlates with bulb cell differentiation into hair shaft cortical and cuticle keratinocytes.

Characterization of a gene encoding a cysteine-rich keratin associated protein synthesized late in rabbit hair follicle differentiation

Many different cysteine-rich proteins are synthesized during hair follicle differentiation, forming part of the interstitial matrix between bundles of intermediate filaments. We have isolated a rabbit gene (rKAP4L), a member of a multigene family that encodes a small cysteine-rich hair keratin associated protein. This is the first complete gene sequence for this family. The rKAP4L gene is expressed in the cortex of rabbit pelage hair follicles at a late stage of hair follicle differentiation, well after the synthesis of the other major hair proteins, the intermediate filament and glycine/tyrosine-rich keratin associated proteins, has commenced. The protein contains 36 mol % cysteine, with a molecular size of 13593 daltons, and its sequence appears to be based on a pentapeptide repeat. It is predicted to adopt a folded conformation characterized by beta-turns interspersed with short stretches of beta-sheet or random coil.