Design, synthesis, and biological evaluation of first-in-class indomethacin-based PROTACs degrading SARS-CoV-2 main protease and with broad-spectrum antiviral activity

To date, Proteolysis Targeting Chimera (PROTAC) technology has been successfully applied to mediate proteasomal-induced degradation of several pharmaceutical targets mainly related to oncology, immune disorders, and neurodegenerative diseases. On the other hand, its exploitation in the field of antiviral drug discovery is still in its infancy. Recently, we described two indomethacin (INM)-based PROTACs displaying broad-spectrum antiviral activity against coronaviruses. Here, we report the design, synthesis, and characterization of a novel series of INM-based PROTACs that recruit either Von-Hippel Lindau (VHL) or cereblon (CRBN) E3 ligases. The panel of INM-based PROTACs was also enlarged by varying the linker moiety. The antiviral activity resulted very susceptible to this modification, particularly for PROTACs hijacking VHL as E3 ligase, with one piperazine-based compound (PROTAC 6) showing potent anti-SARS-CoV-2 activity in infected human lung cells. Interestingly, degradation assays in both uninfected and virus-infected cells with the most promising PROTACs emerged so far (PROTACs 5 and 6) demonstrated that INM-PROTACs do not degrade human PGES-2 protein, as initially hypothesized, but induce the concentration-dependent degradation of SARS-CoV-2 main protease (Mpro) both in Mpro-transfected and in SARS-CoV-2-infected cells. Importantly, thanks to the target degradation, INM-PROTACs exhibited a considerable enhancement in antiviral activity with respect to indomethacin, with EC50 values in the low-micromolar/nanomolar range. Finally, kinetic solubility as well as metabolic and chemical stability were measured for PROTACs 5 and 6. Altogether, the identification of INM-based PROTACs as the first class of SARS-CoV-2 Mpro degraders demonstrating activity also in SARS-CoV-2-infected cells represents a significant advance in the development of effective, broad-spectrum anti-coronavirus strategies.

The hope and hype of ellagic acid and urolithins as ligands of SARS-CoV-2 Nsp5 and inhibitors of viral replication

Non-structural protein 5 (Nsp5) is a cysteine protease that plays a key role in SARS-CoV-2 replication, suppressing host protein synthesis and promoting immune evasion. The investigation of natural products as a potential strategy for Nsp5 inhibition is gaining attention as a means of developing antiviral agents. In this work, we have investigated the physicochemical properties and structure-activity relationships of ellagic acid and its gut metabolites, urolithins A-D, as ligands of Nsp5. Results allow us to identify urolithin D as promising ligand of Nsp5, with a dissociation constant in the nanomolar range of potency. Although urolithin D is able to bind to the catalytic cleft of Nsp5, the appraisal of its viral replication inhibition against SARS-CoV-2 in Vero E6 assay highlights a lack of activity. While these results are discussed in the framework of the available literature reporting conflicting data on polyphenol antiviral activity, they provide new clues for natural products as potential viral protease inhibitors.

Estimating the hydrophobicity extent of molecular fragments using reversed-phase liquid chromatography

A fast HPLC method was developed to study the hydrophobicity extent of pharmaceutically relevant molecular fragments. By this strategy, the reduced amount of sample available for physico-chemical evaluations in early-phase drug discovery programs does not represent a limiting factor. The sixteen acid fragments investigated were previously synthesized also determining potentiometrically their experimental log D values. For four fragments it was not possible to determine such property since their values were outside of the instrumental working range (2 < pKa  < 12). An RP-HPLC method was therefore optimized. For each scrutinized method, some derived chromatographic indices were calculated, and Pearson's correlation coefficient (r) allowed to select the so-called "φ0 index" as the best correlating with the log D. Thew s p H ${}_w^spH$ was fixed at 3.5 and a modification of some variables [organic modifier (methanol vs. ACN), stationary phase (octyl vs. octadecyl), presence/absence of the additives n-octanol, n-butylamine, and n-octylamine], allowed to select the best correlation conditions, producing a r = 0.94 (p < 0.001). Importantly, the φ0 index enabled the estimation of log D values for four fragments which were unattainable by potentiometric titration. Moreover, a series of molecular descriptors were calculated to identify the chemical characteristics of the fragments explaining the obtained φ0 . The number of hydrogen bond donors and the index of cohesive interaction correlated with the experimental data.

Combining Solid-State NMR with Structural and Biophysical Techniques to Design Challenging Protein-Drug Conjugates

Several protein-drug conjugates are currently being used in cancer therapy. These conjugates rely on cytotoxic organic compounds that are covalently attached to the carrier proteins or that interact with them via non-covalent interactions. Human transthyretin (TTR), a physiological protein, has already been identified as a possible carrier protein for the delivery of cytotoxic drugs. Here we show the structure-guided development of a new stable cytotoxic molecule based on a known strong binder of TTR and a well-established anticancer drug. This example is used to demonstrate the importance of the integration of multiple biophysical and structural techniques, encompassing microscale thermophoresis, X-ray crystallography and NMR. In particular, we show that solid-state NMR has the ability to reveal effects caused by ligand binding which are more easily relatable to structural and dynamical alterations that impact the stability of macromolecular complexes.

A back-door insights into the modulation of Src kinase activity by the polyamine spermidine

Src is a protein tyrosine kinase commonly activated downstream of transmembrane receptors and plays key roles in cell growth, migration and survival signaling pathways. In conventional dendritic cells (cDCs), Src is involved in the activation of the non-enzymatic functions of indoleamine 2,3-dioxygenase 1 (IDO1), an immunoregulatory molecule endowed with both catalytic activity and signal transducing properties. Prompted by the discovery that the metabolite spermidine confers a tolerogenic phenotype on cDCs that is dependent on both the expression of IDO1 and the activity of Src kinase, we here investigated the spermidine mode of action. We found that spermidine directly binds Src in a previously unknown allosteric site located on the backside of the SH2 domain and thus acts as a positive allosteric modulator of the enzyme. Besides confirming that Src phosphorylates IDO1, here we showed that spermidine promotes the protein-protein interaction of Src with IDO1. Overall, this study may pave the way toward the design of allosteric modulators able to switch on/off the Src-mediated pathways, including those involving the immunoregulatory protein IDO1.

A multicentric consortium study demonstrates that dimethylarginine dimethylaminohydrolase 2 is not a dimethylarginine dimethylaminohydrolase

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) protects against cardiovascular disease by metabolising the risk factor asymmetric dimethylarginine (ADMA). However, the question whether the second DDAH isoform, DDAH2, directly metabolises ADMA has remained unanswered. Consequently, it is still unclear if DDAH2 may be a potential target for ADMA-lowering therapies or if drug development efforts should focus on DDAH2's known physiological functions in mitochondrial fission, angiogenesis, vascular remodelling, insulin secretion, and immune responses. Here, an international consortium of research groups set out to address this question using in silico, in vitro, cell culture, and murine models. The findings uniformly demonstrate that DDAH2 is incapable of metabolising ADMA, thus resolving a 20-year controversy and providing a starting point for the investigation of alternative, ADMA-independent functions of DDAH2.

Stabilization of the Dimeric State of SARS-CoV-2 Main Protease by GC376 and Nirmatrelvir

The main protease (Mpro or 3CLpro) is an enzyme that is evolutionarily conserved among different genera of coronaviruses. As it is essential for processing and maturing viral polyproteins, Mpro has been identified as a promising target for the development of broad-spectrum drugs against coronaviruses. Like SARS-CoV and MERS-CoV, the mature and active form of SARS-CoV-2 Mpro is a dimer composed of identical subunits, each with a single active site. Individual monomers, however, have very low or no catalytic activity. As such, inhibition of Mpro can be achieved by molecules that target the substrate binding pocket to block catalytic activity or target the dimerization process. In this study, we investigated GC376, a transition-state analog inhibitor of the main protease of feline infectious peritonitis coronavirus, and Nirmatrelvir (NMV), an oral, bioavailable SARS-CoV-2 Mpro inhibitor with pan-human coronavirus antiviral activity. Our results show that both GC376 and NMV are capable of strongly binding to SARS-CoV-2 Mpro and altering the monomer-dimer equilibrium by stabilizing the dimeric state. This behavior is proposed to be related to a structured hydrogen-bond network established at the Mpro active site, where hydrogen bonds between Ser1' and Glu166/Phe140 are formed in addition to those achieved by the latter residues with GC376 or NMV.

Turning a Tumor Microenvironment Pitfall into Opportunity: Discovery of Benzamidoxime as PD-L1 Ligand with pH-Dependent Potency

PD-1/PD-L1 protein complex is attracting a great deal of interest as a drug target for the design of immune therapies able to block its assembly. Although some biologic drugs have entered clinical use, their poor response rate in patients are demanding further efforts to design small molecule inhibitors of PD-1/PD-L1 complex with higher efficacy and optimal physicochemical properties. Dysregulation of pH in the tumor microenvironment is indeed one of the key mechanisms promoting drug resistance and lack of response in cancer therapy. Integrating computational and biophysical approaches, herein we report a screening campaign that has led to identifying VIS310 as a novel ligand of PD-L1, with physicochemical properties enabling a pH-dependent binding potency. Additional optimization efforts by analogue-based screening have been instrumental to disclosing VIS1201, which exhibits improved binding potency against PD-L1 and is able to inhibit PD-1/PD-L1 complex formation in a ligand binding displacement assay. While providing preliminary structure–activity relationships (SARs) of a novel class of PD-L1 ligands, our results lay the foundation for the discovery of immunoregulatory small molecules resilient to tumor microenvironmental conditions for escaping drug-resistance mechanisms.

554 HYPERLIPOPROTEIN(A) AND PREMATURE CORONARY ARTERY DISEASE: A CALL FOR ACTION

Background and Aims

elevated Lipoprotein (a) levels are well recognized as a genetic risk factor for atherothrombotic events. Recently, new therapeutic approaches – such as small interfering RNA (siRNA) and antisense oligonucleotides (ASOs) – have been developed and are under evaluation in phase 3 trials.

Evidences from literature suggest the need for screening Lp(a) in premature coronary artery disease. Aim of our study was to evaluate, in a real world scenario: 1) the percentage of premature CAD in whom clinicians choose to screen Lp(a); 2) the prevalence of hyperLp(a) in premature CAD.

Methods

we retrospectively evaluated data of patients admitted for acute coronary syndrome at Department of Cardiology of Careggi University Hospital, Florence, between 1st January 2018 and 31th July 2022. Inclusion criteria were: age &lt; 50 years for men and &lt; 55 years for women; confirmed diagnosis of acute coronary syndrome with obstructive coronary artery disease at hospital discharge.

Results

we selected 226 patients (50 F and 176 M; total median age 46 years, F median age 49 years, M median age 45 years). LDL median values at admission were 117.12 mg/dl). Nine out of 226 pts (3.9%) had LDL levels higher than 190 mg/dl, suggesting the possible diagnosis of Heterozygous Familial Hypercholesterolemia (with respect to the expected prevalence in the general population: 1/250 (0.004%). No patient had hepatic or thyroid disease. Sixty-eight out of 226 pts (30%) had triglycerides levels higher than 150 mg/dl; 41/226 (18.1%) with levels higher than 200 mg/dl. As regards Lp(a) levels, a dosage was performed in 93/226 patients (41.2%). We found that lipoprotein dosage was required more frequently in the 2020, 2021 and 2022 years (respectively in the 61%, 49% and 70% of patients) than in the 2018 and 2019 years (respectively in the 27% and 23% of patients) (Figure 1). Among patients in whom lipoprotein was dosed, elevated Lp(a) levels (&gt; 300 mg/L) were documented in 45/93 (48.4%). 15/93 (16.1%) patients had extreme elevated Lp(a) levels (&gt; 700 mg/L) (Figure 2). In two patients we documented both extreme Lp(a) levels and LDL levels higher than 190 mg/dl; in the other patients, elevated Lp(a) levels were the only lipid parameter out of range, and the only risk factor for premature CAD. By comparing these patients with an historical cohort of patients with ACS and age &gt;50 and 55 yrs in men and women respectively, we found at a multivariate analysis adjusted for classical risk factors that both elevated Lp(a) levels (OR:2.1 (95% CI 1.3–4.2), p&lt;0.005) and extreme elevated Lp(a) levels were significantly associated with the risk of premature CAD (OR: 1.8 (95% CI 1.4–3.9); p&lt;0.05).

Conclusions

these results demonstrated that: 1) it is urgent, from a clinical point of view, to apply screening protocols in premature CAD including Lp(a) dosage; 2) elevated Lp(a) levels, and in particular extreme elevated Lp(a) levels, have an elevated prevalence in a population of premature CAD and are significantly and independently associated with the disease.

Peripheral artery disease and all-cause and cardiovascular mortality in patients with NAFLD

PURPOSE

Cardiovascular disease (CVD) is the first cause of death in patients with non-alcoholic fatty liver disease (NAFLD) and risk stratification is recommended by current guidelines. The aim of this study is to assess the prevalence of peripheral arterial disease (PAD) in patients with NAFLD and its association with all-cause and cardiovascular disease (CVD) mortality.

METHODS

9145 participants 40 years or older attended a mobile examination center visit in the 1999-2004 cycles of the National Health and Nutrition Examination Survey. PAD was defined as an ankle-brachial index (ABI) < 0.90 in either of the legs and mortality data through December 2015 were obtained from the National Death Index. NAFLD was defined by a fatty liver index ≥ 60 in the absence of other liver conditions, leading to a final sample of 3094 subjects.

RESULTS

The overall prevalence of PAD was 5.9% (95% CI 5.0-6.9). Over a median follow-up of 13 years, 876 participants died, 208 of cardiovascular causes. Incidence rates of all-cause mortality (for 1000 person-years) were 20.2 (95% CI 18.7-21.7) and 70.0 (95% CI 60.1-81.6) for participants without and with PAD, respectively. Multivariable-adjusted Cox proportional hazard models showed that PAD was associated with a higher risk of all-cause (1.8, 95% CI 1.4-2.4) and cardiovascular mortality (HR 2.5, 95% CI 1.5-4.3) after adjustment for potential confounders including prevalent CVD.

CONCLUSION

Current guidelines strongly encourage the screening of CVD in patients with NAFLD and the use of the simple and inexpensive measurement of ABI in routine clinical practice may find indication.

Can CHA2DS2-VASc and HAS-BLED Foresee the Presence of Cerebral Microbleeds, Lacunar and Non-Lacunar Infarcts in Elderly Patients With Atrial Fibrillation? Data From Strat-AF Study

Anticoagulants reduce embolic risk in atrial fibrillation (AF), despite increasing hemorrhagic risk. In this context, validity of congestive heart failure, hypertension, age ≥ 75 years, diabetes, stroke, vascular disease, age 65-74 years and sex category (CHA2DS2-VASc) and hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly (HAS-BLED) scales, used to respectively evaluate thrombotic and hemorrhagic risks, is incomplete. In patients with AF, brain MRI has led to the increased detection of "asymptomatic" brain changes, particularly those related to small vessel disease, which also represent the pathologic substrate of intracranial hemorrhage, and silent brain infarcts, which are considered risk factors for ischemic stroke. Routine brain MRI in asymptomatic patients with AF is not yet recommended. Our aim was to test predictive ability of risk stratification scales on the presence of cerebral microbleeds, lacunar, and non-lacunar infarcts in 170 elderly patients with AF on oral anticoagulants. Ad hoc developed R algorithms were used to evaluate CHA2DS2-VASc and HAS-BLED sensitivity and specificity on the prediction of cerebrovascular lesions: (1) Maintaining original items' weights; (2) augmenting weights' range; (3) adding cognitive, motor, and depressive scores. Accuracy was poor for each outcome considering both scales either in phase 1 or phase 2. Accuracy was never improved by the addition of cognitive scores. The addition of motor and depressive scores to CHA2DS2-VASc improved accuracy for non-lacunar infarcts (sensitivity = 0.70, specificity = 0.85), and sensitivity for lacunar-infarcts (sensitivity = 0.74, specificity = 0.61). Our results are a very first step toward the attempt to identify those elderly patients with AF who would benefit most from brain MRI in risk stratification.

Critical Assessment of a Structure-Based Screening Campaign for IDO1 Inhibitors: Tips and Pitfalls

Over the last two decades, indoleamine 2,3-dioxygenase 1 (IDO1) has attracted wide interest as a key player in immune regulation, fostering the design and development of small molecule inhibitors to restore immune response in tumor immunity. In this framework, biochemical, structural, and pharmacological studies have unveiled peculiar structural plasticity of IDO1, with different conformations and functional states that are coupled to fine regulation of its catalytic activity and non-enzymic functions. The large plasticity of IDO1 may affect its ligand recognition process, generating bias in structure-based drug design campaigns. In this work, we report a screening campaign of a fragment library of compounds, grounding on the use of three distinct conformations of IDO1 that recapitulate its structural plasticity to some extent. Results are instrumental to discuss tips and pitfalls that, due to the large plasticity of the enzyme, may influence the identification of novel and differentiated chemical scaffolds of IDO1 ligands in structure-based screening campaigns.

One Key and Multiple Locks: Substrate Binding in Structures of Tryptophan Dioxygenases and Hydroxylases

Since its discovery at the beginning of the past century, the essential nutrient l-Tryptophan (l-Trp) and its catabolic pathways have acquired an increasing interest in an ever wider scientific community for their pivotal roles in underlying many important physiological functions and associated pathological conditions. As a consequence, enzymes catalyzing rate limiting steps along l-Trp catabolic pathways - including IDO1, TDO, TPH1 and TPH2 - have turned to be interesting drug targets for the design and development of novel therapeutic agents for different disorders such as carcinoid syndrome, cancer and autoimmune diseases. This article provides a fresh comparative overview on the most recent advancements that crystallographic studies, biophysical and computational works have brought on structural aspects and molecular recognition patterns of these enzymes toward l-Trp. Finally, a conformational analysis of l-Trp is also discussed as part of the molecular recognition process governing the binding of a substrate to its cognate enzymes.

Impact of using different biomarkers of liver fibrosis on hepatologic referral of individuals with severe obesity and NAFLD

PURPOSE

The purpose of this study was to estimate how many individuals with severe obesity and NAFLD should be referred to hepatologists according to the EASL-EASD-EASO guidelines and whether the choice of specific indicators of liver fibrosis would significantly impact the number of referrals.

METHODS

This was a single-center retrospective study of 495 individuals with severe obesity screened at our institution between 2012 and 2018 for a bariatric surgery intervention. The guidelines were applied using the NAFLD Liver Fat Score (NLFS) to assess the presence of steatosis and the NAFLD fibrosis score (NFS), Fibrosis-4 (FIB-4) and Hepamet Fibrosis Score (HFS) to assess the risk of advanced fibrosis.

RESULTS

Three hundred and seventy-nine patients (76.6%) had evidence of liver steatosis. The application of the guidelines would lead to referral of 66.3% of patients using NFS, 31.7% using FIB-4 and 34.2% using HFS. When referrals due to abnormal liver function tests were excluded, these percentages dropped to 55.8%, 7.3% and 12.1%, respectively. The strongest inter-biomarker agreement was found between FIB-4 and HFS (κ = 0.86, 95% CI 0.815-0.910).

CONCLUSION

Strict application of the guidelines in individuals with severe obesity would probably lead to over-referral, although a great variability exists among the different scores.

Antithyroid drug treatment for Graves' disease: baseline predictive models of relapse after treatment for a patient-tailored management

BACKGROUND

Antithyroid drugs (ATDs) are first-line treatment for Graves' hyperthyroidism worldwide, but relapses are frequent. The reliability of individual risk factors to predict at baseline subsequent relapse is poor. Predictive scores grouping single risk factors might help to select the best treatment (pharmacological vs. ablative).

OBJECTIVE

To assess the predictivity of a recently developed score (Clinical Severity Score, CSS) and to compare it with another score (GREAT score).

PATIENTS

A retrospective observational, single-center study was conducted of 387 consecutive, newly diagnosed Graves' patients, who completed an 18-24 months ATD course and were followed for at least 2 years.

RESULTS

Hyperthyroidism relapsed in 185 patients (48%). At diagnosis and before treatment, the relapse group had higher serum TSH-receptor antibody and free thyroxine levels and larger goiters than the remission group, with no differences in Graves' orbitopathy prevalence and severity. In the multivariate analyses, only large goiter size was significantly associated with an increased recurrence hazard ratio. Using CSS, the risk of relapse increased from 36% in the mild category and 49% in the moderate category to 59% in the severe category, with quite a good area under the curve (AUC) (0.60; 95% CI: 0.55; 0.66). GREAT score showed an increase in relapse from 34% for class I (mild) and 49% for class II (moderate) to 64% for class III (severe) (AUC, 0.63; CI: 0.58; 0.68).

CONCLUSIONS

Both CSS and GREAT score are useful, although imperfect, tools to predict at baseline relapse of hyperthyroidism after treatment. In real life they may help the clinician to tailor a treatment for newly diagnosed Graves' hyperthyroidism.

Physical performance in newly diagnosed hypothyroidism: a pilot study

OBJECTIVE

Hypothyroidism is complicated by neuromuscular symptoms (myalgias, slowness of movements, and tiredness) and signs (easy fatigability and cramps), which may have a negative impact on general well-being and quality of life. In a pilot, prospective, controlled study, we investigated the features of muscle dysfunction in hypothyroidism by disease questionnaire, biochemical measures, and physical performance tests.

MATERIALS AND METHODS

Fifty-seven consecutive patients with newly diagnosed hypothyroidism were enrolled, 27 subclinical (S-Hypo) and 30 overt (O-Hypo). A series of 30 euthyroid subjects, with similar demographic characteristics, served as controls. Patients were administered a short disease questionnaire and underwent laboratory exams and standardized physical tests, both at baseline and after restoration of biochemical euthyroidism.

RESULTS

Compared to euthyroid controls, the O-Hypo group showed significantly higher prevalence of neuromuscular symptoms and significantly higher serum creatine phosphokinase (CPK) levels (p value < 0.0001). S-Hypo had slightly higher CPK levels and prevalence of neuromuscular symptoms than controls. Both S-Hypo and O-Hypo patients performed worse than controls in the six-minute walking test. Differences between patients and controls in handgrip strength test and timed chair standing test failed to reach statistical significance (although a trend was noticeable), possibly due to the small sample size. In O-Hypo, an inverse correlation was found between CPK levels and the handgrip strength test (p value < 0.001). Restoration of euthyroidism was associated with normalization of questionnaire responses, six-minute walking test, as well as serum CPK levels.

CONCLUSION

In addition to neuromuscular symptoms, hypothyroidism is associated with abnormalities of physical performance. The six-minute walking test is the most valuable test to assess this aspect. In the pilot study, levothyroxine therapy could reverse muscle functional abnormalities.

The phenotype of newly diagnosed Graves' disease in Italy in recent years is milder than in the past: results of a large observational longitudinal study

OBJECTIVE

The Merseburg triad (hyperthyroidism, goiter, and orbitopathy) characterizes classical description of Graves' disease (GD). Aim of this observational, longitudinal study was to evaluate the current clinical features of newly diagnosed GD in Italy.

MATERIALS AND METHODS

In two Northern Italy centers (Varese and Pavia), 283 consecutive patients (211 women, 72 men; mean age 47.4 years) with newly diagnosed GD were recruited in the years 2010-2014. Diagnosis was based on established criteria, and thyroid volume was assessed by ultrasonography. A clinical severity score (CSS) to assess the overall disease severity was developed by grading each component of the Merseburg triad.

RESULTS

At diagnosis, 45 % of patients had no goiter, and 30 % had a small goiter. The proportion of goitrous patients was much lower than in two Italian studies performed 20-30 years ago. Hyperthyroidism was subclinical in 16 % and mild in 29 % of patients, and Graves' orbitopathy was present in 20 %, usually mild, and active in only 2.5 % of patients. Using the CSS, less than half (44 %) of the patients had severe GD, while 22 % had mild and 34 % moderate disease. CSS was associated with a significantly higher risk of poorly controlled hyperthyroidism at 6 months.

CONCLUSIONS

In Italy, a relevant proportion of Graves' patients at diagnosis have mild to moderate GD; about half of them have no goiter, slightly less than one-fifth have subclinical hyperthyroidism, and only 20 % have GO. Thus, the clinical phenotype of GD is milder than in the past, possibly due to both earlier diagnosis and treatment, and improved iodine nutrition.

Albumin as marker for susceptibility to metal ions in metal-on-metal hip prosthesis patients

Metal-on-metal (MoM) hip prostheses are known to release chromium and cobalt (Co), which negatively affect the health status, leading to prosthesis explant. Albumin (ALB) is the main serum protein-binding divalent transition metals. Its binding capacity can be affected by gene mutations or modification of the protein N-terminal region, giving the ischaemia-modified albumin (IMA). This study evaluated ALB, at gene and protein level, as marker of individual susceptibility to Co in MoM patients, to understand whether it could be responsible for the different management of this ion. Co was measured in whole blood, serum and urine of 40 MoM patients. A mutational screening of ALB was performed to detect links between mutations and metal binding. Finally, serum concentration of total ALB and IMA were measured. Serum total ALB concentration was in the normal range for all patients. None of the subjects presented mutations in the investigated gene. Whole blood, serum and urine Co did not correlate with serum total ALB or IMA, although IMA was above the normal limit in most subjects. The individual susceptibility is very important for patients’ health status. Despite the limited results of this study, we provide indications on possible future investigations on the toxicological response to Co.

Takayasu's arteritis associated with Crohn's disease. Report of a case

The authors report a rare case of Takayasu's arteritis with aortic arch and abdominal aorta involvement associated with Crohn's disease of the colon which both occurred in a young female patient. The coexistence of two immune mediated diseases in the same subject is unusual for they are generally considered to be independent of each other, however a hypothesis of their possible interrelationship is put forward.

[Tularemia: considerations on a new case in the Monte Amiata]

One sporadic case of tularemia induced by direct contact with an infected hare is described. Human epidemiological data of the last ten years in Tuscany, emphasize that this infection, although at low incidence, shows the presence and persistence of Francisella tularensis in the animals and the ensuing transmission to humans so that it continues to be responsible for significant morbididy in "at risk" territories. Difficulties in the differential diagnosis, above all for glandular and pharyngeal forms, are reviewed.