A Facile Access to Green Fluorescent Albumin Derivatives

A Morita-Baylis-Hillman Adduct (MBHA) derivative bearing a triphenylamine moiety was found to react with human serum albumin (HSA) shifting its emission from the blue to the green-yellow thus leading to green fluorescent albumin (GFA) derivatives and enlarging the platform of probes for aggregation-induced fluorescent-based detection techniques. A possible interaction of MBHA derivative 7 with a lipophilic pocket within the HSA structure was suggested by docking studies. DLS experiments showed that the reaction with HSA induce a conformational change of the protein contributing to the aggregation process of GFA derivatives. The results of investigations on the biological properties suggested that GFA retained the ability of binding drug molecules such as warfarin and diazepam. Finally, cytotoxicity evaluation studies suggested that, although the MBHA derivative 7 at 0.1 μg/mL affected the percentage of cell viability in comparison to the negative control, it cannot be considered cytotoxic, whereas at all the other concentrations≥0.5 μg/mL resulted cytotoxic at different extent.

The discovery of aryl-2-nitroethyl triamino pyrimidines as anti-Trypanosoma brucei agents

Pteridine reductase 1 (PTR1) is a catalytic protein belonging to the folate metabolic pathway in Trypanosmatidic parasites. PTR1 is a known target for the medicinal chemistry development of antiparasitic agents against Trypanosomiasis and Leishmaniasis. In previous studies, new nitro derivatives were elaborated as PTR1 inhibitors. The compounds showing a diamino-pyrimidine core structure were previously developed but they showed limited efficacy. Therefore, a new class of phenyl-, heteroaryl- and benzyloxy-nitro derivatives based on the 2-nitroethyl-2,4,6-triaminopyrimidine scaffold were designed and tested. The compounds were assayed for their ability to inhibit T. brucei and L. major PTR1 enzymes and for their antiparasitic activity towards T. brucei and L. infantum parasites. To understand the structure-activity relationships of the compounds against TbPTR1, the X-ray crystallographic structure of the 2,4,6-triaminopyrimidine (TAP) was obtained and molecular modelling studies were performed. As a next step, only the most effective compounds against T. brucei were then tested against the amastigote cellular stage of T. cruzi, searching for a broad-spectrum antiprotozoal agent. An early ADME-Tox profile evaluation was performed. The early toxicity profile of this class of compounds was investigated by measuring their inhibition of hERG and five cytochrome P450 isoforms (CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4), cytotoxicity towards A549 cells and mitochondrial toxicity. Pharmacokinetic studies (SNAP-PK) were performed on selected compounds using hydroxypropyl-β-cyclodextrins (50 % w/v) to preliminarily study their plasma concentration when administered per os at a dose of 20 mg/kg. Compound 1p, showed the best pharmacodynamic and pharmacokinetic properties, can be considered a good candidate for further bioavailability and efficacy studies.

Antitarget, Anti-SARS-CoV-2 Leads, Drugs, and the Drug Discovery-Genetics Alliance Perspective

The most advanced antiviral molecules addressing major SARS-CoV-2 targets (Main protease, Spike protein, and RNA polymerase), compared with proteins of other human pathogenic coronaviruses, may have a short-lasting clinical efficacy. Accumulating knowledge on the mechanisms underlying the target structural basis, its mutational progression, and the related biological significance to virus replication allows envisaging the development of better-targeted therapies in the context of COVID-19 epidemic and future coronavirus outbreaks. The identification of evolutionary patterns based solely on sequence information analysis for those targets can provide meaningful insights into the molecular basis of host-pathogen interactions and adaptation, leading to drug resistance phenomena. Herein, we will explore how the study of observed and predicted mutations may offer valuable suggestions for the application of the so-called "synthetic lethal" strategy to SARS-CoV-2 Main protease and Spike protein. The synergy between genetics evidence and drug discovery may prioritize the development of novel long-lasting antiviral agents.

Optimization of 1,2,4-Triazole-3-thiones toward Broad-Spectrum Metallo-β-lactamase Inhibitors Showing Potent Synergistic Activity on VIM- and NDM-1-Producing Clinical Isolates

Metallo-β-lactamases (MBLs) contribute to the resistance of Gram-negative bacteria to carbapenems, last-resort antibiotics at hospital, and MBL inhibitors are urgently needed to preserve these important antibacterial drugs. Here, we describe a series of 1,2,4-triazole-3-thione-based inhibitors displaying an α-amino acid substituent, which amine was mono- or disubstituted by (hetero)aryl groups. Compounds disubstituted by certain nitrogen-containing heterocycles showed submicromolar activities against VIM-type enzymes and strong NDM-1 inhibition (K_i = 10-30 nM). Equilibrium dialysis, native mass spectrometry, isothermal calorimetry (ITC), and X-ray crystallography showed that the compounds inhibited both VIM-2 and NDM-1 at least partially by stripping the catalytic zinc ions. These inhibitors also displayed a very potent synergistic activity with meropenem (16- to 1000-fold minimum inhibitory concentration (MIC) reduction) against VIM-type- and NDM-1-producing ultraresistant clinical isolates, including Enterobacterales and Pseudomonas aeruginosa. Furthermore, selected compounds exhibited no or moderate toxicity toward HeLa cells, favorable absorption, distribution, metabolism, excretion (ADME) properties, and no or modest inhibition of several mammalian metalloenzymes.

Structural Characterization of Human Heat Shock Protein 90 N-Terminal Domain and Its Variants K112R and K112A in Complex with a Potent 1,2,3-Triazole-Based Inhibitor

Heat shock protein 90 (Hsp90) is a ubiquitous molecular chaperone that stabilizes client proteins in a folded and functional state. It is composed of two identical and symmetrical subunits and each monomer consists of three domains, the N-terminal (NTD), the middle (MD), and the C-terminal domain (CTD). Since the chaperone activity requires ATP hydrolysis, molecules able to occupy the ATP-binding pocket in the NTD act as Hsp90 inhibitors, leading to client protein degradation and cell death. Therefore, human Hsp90 represents a validated target for developing new anticancer drugs. Since protozoan parasites use their Hsp90 to trigger important transitions between different stages of their life cycle, this protein also represents a profitable target in anti-parasite drug discovery. Nevertheless, the development of molecules able to selectively target the ATP-binding site of protozoan Hsp90 is challenging due to the high homology with the human Hsp90 NTD (hHsp90-NTD). In a previous work, a series of potent Hsp90 inhibitors based on a 1,4,5-trisubstituted 1,2,3-triazole scaffold was developed. The most promising inhibitor of the series, JMC31, showed potent Hsp90 binding and antiproliferative activity in NCI-H460 cells in the low-nanomolar range. In this work, we present the structural characterization of hHsp90-NTD in complex with JMC31 through X-ray crystallography. In addition, to elucidate the role of residue 112 on the ligand binding and its exploitability for the development of selective inhibitors, we investigated the crystal structures of hHsp90-NTD variants (K112R and K112A) in complex with JMC31.

1,2,4-Triazole-3-Thione Analogues with a 2-Ethylbenzoic Acid at Position 4 as VIM-type Metallo-β-Lactamase Inhibitors

Metallo-β-lactamases (MBLs) are increasingly involved as a major mechanism of resistance to carbapenems in relevant opportunistic Gram-negative pathogens. Unfortunately, clinically efficient MBL inhibitors still represent an unmet medical need .  We previously reported several series of compounds based on the 1,2,4-triazole-3-thione scaffold. In particular, Schiff bases formed between diversely 5-substituted-4-amino compounds and 2-carboxybenzaldehyde were broad-spectrum inhibitors of VIM-type, NDM-1 and IMP-1 MBLs. Unfortunately, they were unable to restore antibiotic susceptibility of MBL-producing bacteria, probably because of poor penetration and/or susceptibility to hydrolysis. To improve their microbiological activity, we developed compounds where the hydrazone-like bond of the Schiff bases was replaced by a stable ethyl link. This small change resulted in a narrower inhibition spectrum, as all compounds were poorly or not inhibiting NDM-1 and IMP-1, but some showed a significantly better activity on VIM-type enzymes, with  K i  values in the μM to sub-μM range. The resolution of the crystallographic structure of VIM-2 in complex with one inhibitor yielded valuable information about their binding mode. Interestingly, several compounds were shown to restore the β-lactam susceptibility of  K. pneumoniae  clinical isolates. In addition, selected compounds were found to be devoid of toxicity toward human cells at high concentration, thus showing promising safety.

Xanthopsin-Like Systems via Site-Specific Click-Functionalization of a Retinoic Acid Binding Protein

The use of light-responsive proteins to control both living or synthetic cells, is at the core of the expanding fields of optogenetics and synthetic biology. It is thus apparent that a richer reaction toolbox for the preparation of such systems is of fundamental importance. Here, we provide a proof-of-principle demonstration that Morita-Baylis-Hillman adducts can be employed to perform a facile site-specific, irreversible and diastereoselective click-functionalization of a lysine residue buried into a lipophilic binding pocket and yielding an unnatural chromophore with an extended π-system. In doing so we effectively open the path to the in vitro preparation of a library of synthetic proteins structurally reminiscent of xanthopsin eubacterial photoreceptors. We argue that such a library, made of variable unnatural chromophores inserted in an easy-to-mutate and crystallize retinoic acid transporter, significantly expand the scope of the recently introduced rhodopsin mimics as both optogenetic and "lab-on-a-molecule" tools.

Iron Binding in the Ferroxidase Site of Human Mitochondrial Ferritin

Ferritins are nanocage proteins that store iron ions in their central cavity as hydrated ferric oxide biominerals. In mammals, further the L (light) and H (heavy) chains constituting cytoplasmic maxi-ferritins, an additional type of ferritin has been identified, the mitochondrial ferritin (MTF). Human MTF (hMTF) is a functional homopolymeric H-like ferritin performing the ferroxidase activity in its ferroxidase site (FS), in which Fe(II) is oxidized to Fe(III) in the presence of dioxygen. To better investigate its ferroxidase properties, here we performed time-lapse X-ray crystallography analysis of hMTF, providing structural evidence of how iron ions interact with hMTF and of their binding to the FS. Transient iron binding sites, populating the pathway along the cage from the iron entry channel to the catalytic center, were also identified. Furthermore, our kinetic data at variable iron loads indicate that the catalytic iron oxidation reaction occurs via a diferric peroxo intermediate followed by the formation of ferric-oxo species, with significant differences with respect to human H-type ferritin.

Evidence of Pyrimethamine and Cycloguanil Analogues as Dual Inhibitors of Trypanosoma brucei Pteridine Reductase and Dihydrofolate Reductase

Trypanosoma and Leishmania parasites are the etiological agents of various threatening neglected tropical diseases (NTDs), including human African trypanosomiasis (HAT), Chagas disease, and various types of leishmaniasis. Recently, meaningful progresses in the treatment of HAT, due to Trypanosoma brucei (Tb), have been achieved by the introduction of fexinidazole and the combination therapy eflornithine-nifurtimox. Nevertheless, due to drug resistance issues and the exitance of animal reservoirs, the development of new NTD treatments is still required. For this purpose, we explored the combined targeting of two key folate enzymes, dihydrofolate reductase (DHFR) and pteridine reductase 1 (PTR1). We formerly showed that the TbDHFR inhibitor cycloguanil (CYC) also targets TbPTR1, although with reduced affinity. Here, we explored a small library of CYC analogues to understand how their substitution pattern affects the inhibition of both TbPTR1 and TbDHFR. Some novel structural features responsible for an improved, but preferential, ability of CYC analogues to target TbPTR1 were disclosed. Furthermore, we showed that the known drug pyrimethamine (PYR) effectively targets both enzymes, also unveiling its binding mode to TbPTR1. The structural comparison between PYR and CYC binding modes to TbPTR1 and TbDHFR provided key insights for the future design of dual inhibitors for HAT therapy.

Dynamic Interplay between Copper Toxicity and Mitochondrial Dysfunction in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder, affecting millions of people worldwide, a number expected to exponentially increase in the future since no effective treatments are available so far. AD is characterized by severe cognitive dysfunctions associated with neuronal loss and connection disruption, mainly occurring in specific brain areas such as the hippocampus, cerebral cortex, and amygdala, compromising memory, language, reasoning, and social behavior. Proteomics and redox proteomics are powerful techniques used to identify altered proteins and pathways in AD, providing relevant insights on cellular pathways altered in the disease and defining novel targets exploitable for drug development. Here, we review the main results achieved by both -omics techniques, focusing on the changes occurring in AD mitochondria under oxidative stress and upon copper exposure. Relevant information arises by the comparative analysis of these results, evidencing alterations of common mitochondrial proteins, metabolic cycles, and cascades. Our analysis leads to three shared mitochondrial proteins, playing key roles in metabolism, ATP generation, oxidative stress, and apoptosis. Their potential as targets for development of innovative AD treatments is thus suggested. Despite the relevant efforts, no effective drugs against AD have been reported so far; nonetheless, various compounds targeting mitochondria have been proposed and investigated, reporting promising results.

Discovery of small molecule inhibitors of Leishmania braziliensis Hsp90 chaperone

Leishmaniasis is a neglected disease caused by the protozoa Leishmania ssp. Environmental differences found by the parasites in the vector and the host are translated into cellular stress, leading to the production of heat shock proteins (Hsp). These are molecular chaperones involved in the folding of nascent proteins as well as in the regulation of gene expression, signalling events and proteostasis. Since Leishmania spp. use Hsp90 to trigger important transitions between their different stages of the life cycle, this protein family becomes a profitable target in anti-parasite drug discovery. In this work, we implemented a multidisciplinary strategy coupling molecular modelling with in vitro assays to identify small molecules able to inhibit Hsp90 from L. braziliensis (LbHsp90). Overall, we identified some compounds able to kill the promastigote form of the L. braziliensis, and to inhibit LbHsp90 ATPase activity.

High-resolution crystal structure of Trypanosoma brucei pteridine reductase 1 in complex with an innovative tricyclic-based inhibitor

The protozoan parasite Trypanosoma brucei is the etiological agent of human African trypanosomiasis (HAT). HAT, together with other neglected tropical diseases, causes serious health and economic issues, especially in tropical and subtropical areas. The classical antifolates targeting dihydrofolate reductase (DHFR) are ineffective towards trypanosomatid parasites owing to a metabolic bypass by the expression of pteridine reductase 1 (PTR1). The combined inhibition of PTR1 and DHFR activities in Trypanosoma parasites represents a promising strategy for the development of new effective treatments for HAT. To date, only monocyclic and bicyclic aromatic systems have been proposed as inhibitors of T. brucei PTR1 (TbPTR1); nevertheless, the size of the catalytic cavity allows the accommodation of expanded molecular cores. Here, an innovative tricyclic-based compound has been explored as a TbPTR1-targeting molecule and its potential application for the development of a new class of PTR1 inhibitors has been evaluated. 2,4-Diaminopyrimido[4,5-b]indol-6-ol (1) was designed and synthesized, and was found to be effective in blocking TbPTR1 activity, with a K_i in the low-micromolar range. The binding mode of 1 was clarified through the structural characterization of its ternary complex with TbPTR1 and the cofactor NADP(H), which was determined to 1.30 Å resolution. The compound adopts a substrate-like orientation inside the cavity that maximizes the binding contributions of hydrophobic and hydrogen-bond interactions. The binding mode of 1 was compared with those of previously reported bicyclic inhibitors, providing new insights for the design of innovative tricyclic-based molecules targeting TbPTR1.

Identification of Phosphate-Containing Compounds as New Inhibitors of 14-3-3/c-Abl Protein-Protein Interaction

The 14-3-3/c-Abl protein-protein interaction (PPI) is related to carcinogenesis and in particular to pathogenesis of chronic myeloid leukemia (CML). Previous studies have demonstrated that molecules able to disrupt this interaction improve the nuclear translocation of c-Abl, inducing apoptosis in leukemia cells. Through an X-ray crystallography screening program, we have identified two phosphate-containing compounds, inosine monophosphate (IMP) and pyridoxal phosphate (PLP), as binders of human 14-3-3σ, by targeting the protein amphipathic groove. Interestingly, they also act as weak inhibitors of the 14-3-3/c-Abl PPI, demonstrated by NMR, SPR, and FP data. A 37-compound library of PLP and IMP analogues was investigated using a FP assay, leading to the identification of three further molecules acting as weak inhibitors of the 14-3-3/c-Abl complex formation. The antiproliferative activity of IMP, PLP, and the three derivatives was tested against K-562 cells, showing that the parent compounds had the most pronounced effect on tumor cells. PLP and IMP were also effective in promoting the c-Abl nuclear translocation in c-Abl overexpressing cells. Further, these compounds demonstrated low cytotoxicity on human Hs27 fibroblasts. In conclusion, our data suggest that 14-3-3σ targeting compounds represent promising hits for further development of drugs against c-Abl-dependent cancers.

Targeting Methyltransferases in Human Pathogenic Bacteria: Insights into Thymidylate Synthase (TS) and Flavin-Dependent TS (FDTS)

In cells, thymidylate synthases provide the only de novo source of 2′-deoxythymidine-5′-monophosphate (dTMP), required for DNA synthesis. The activity of these enzymes is pivotal for cell survival and proliferation. Two main families of thymidylate synthases have been identified in bacteria, folate-dependent thymidylate synthase (TS) and flavin-dependent TS (FDTS). TS and FDTS are highly divergent enzymes, characterized by exclusive catalytic mechanisms, involving different sets of cofactors. TS and FDTS mechanisms of action have been recently revised, providing new perspectives for the development of antibacterial drugs targeting these enzymes. Nonetheless, some catalytic details still remain elusive. For bacterial TSs, half-site reactivity is still an open debate and the recent evidences are somehow controversial. Furthermore, different behaviors have been identified among bacterial TSs, compromising the definition of common mechanisms. Moreover, the redox reaction responsible for the regeneration of reduced flavin in FDTSs is not completely clarified. This review describes the recent advances in the structural and functional characterization of bacterial TSs and FDTSs and the current understanding of their mechanisms of action. Furthermore, the recent progresses in the development of inhibitors targeting TS and FDTS in human pathogenic bacteria are summarized.

Chemically stable inhibitors of 14-3-3 protein–protein interactions derived from BV02

14-3-3 are regulatory proteins that through protein–protein interactions (PPI) with numerous binding partners could be involved in several human diseases, including cancer, neurodegenerative disorders, and pathogens infections. Following our research interest in the development of 14-3-3 PPI inhibitors, here we exploited the privileged 4-aminoantipyrine scaffold in the design and synthesis of some derivatives endowed with antiproliferative activity against K-562 cells, and capable of binding to recombinant 14-3-3σ as evidenced by NMR spectroscopy. The binding mode was further explored by molecular modelling, while coupling confocal microscopy with intensitometric analysis showed that compound 1 was able to promote the nuclear translocation of c-Abl at low micromolar concentrations. Overall, 1 is chemically stable compared to parent 14-3-3 PPI inhibitors, and thus emerged as a confirmed hit for further development.

Probing the role of Arg97 in Heat shock protein 90 N-terminal domain from the parasite Leishmania braziliensis through site-directed mutagenesis on the human counterpart

In Brazil, the mucocutaneous form of leishmaniasis, caused by the parasite Leishmania braziliensis, is a widespread and very challenging disease responsible for disfiguration and, in the most severe cases, death. Heat shock protein 90 (Hsp90) is a ubiquitous molecular chaperone playing a pivotal role in the folding process of client proteins, and therefore its activity is fundamental for cell survival and proliferation. Since the chaperone activity requires ATP hydrolysis, molecules able to occupy the ATP binding pocket in the protein N-terminal domain (NTD) act as Hsp90 inhibitors. The development of selective molecules targeting the ATPase site of protozoan Hsp90 is tricky for the high homology with the human Hsp90 NTD (hNTD). Notably, only the human Lys112 is replaced by Arg97 in the L. braziliensis enzyme. Recently, this difference has been probed to design selective inhibitors targeting parasite Hsp90s. Here, a reliable protocol for expression and purification of LbHsp90-NTD (LbNTD) was developed but its structural characterization was unsuccessful. The role of Arg97 in LbNTD was hence probed by means of the "leishmanized" K112R variant of hNTDα. To deeply investigate the role of this residue, also the hNTDα K112A variant was generated. Structural studies performed on hNTDα and its variants using various ADP and ATP analogues and cAMP revealed that this residue is not crucial for nucleotide binding. This finding strongly suggests that Arg97 in LbNTD and more generally the conserved arginine residue in parasite Hsp90s are not exploitable for the development of selective inhibitors.

Efficacy of complex herbal compound of Echinacea angustifolia (Imoviral® Junior) in recurrent upper respiratory tract infections during pediatric age: preliminary results

AIM

Among pediatric population the recurrent upper respiratory tract infections are very common. Several phytotherapies are been proposed as support therapies and, in particular, the efficacy of Echinacea angustifolia is controversial. This paper presents an evaluation of a new herbal compound in the treatment of recurrent upper respiratory tract infections in a pediatric cohort.

METHODS

An immunostimulant herbal compound of Echinacea angustifolia, Arabinogalactan, Acerola (Vitamin C), Beta- Glucan e Zinc (Imoviral® Junior) was given to 37 children affected by recurrent pharyngotonsillitis or otitis media.

RESULTS

The mean number of inflammatory episodes (i.e. tonsillitis or otitis media) during 6 months before treatment was 3±2.19, during the 6 months following treatment initiation it was 1±0.93 (P=0.04). After the complete treatment, 77% of children reported an improvement of chronic inflammatory in frequency of acute episodes. The total score of a questionnaire about life quality is improved (P=0.04). Finally, none collateral effects was occurred.

CONCLUSION

The herbal compound of echinacea, beta-glucan, vitamin c, arabinoglactan and zinc (Imoviral® Junior) can improve the quality of life in pediatric patients affected by recurrent pharyngotonsillitis and otitis media without contralateral effects.

Lesion load quantification in serial MR of early relapsing multiple sclerosis patients in azathioprine treatment. A retrospective study

Azathioprine (AZA) has a slight but consistent effect on clinical outcome in multiple sclerosis (MS), but very few data are available on magnetic resonance imaging (MRI) changes. We performed a retrospective study aimed to quantify changes of lesion load in two serial proton density weighted MRI sequences (TR 2500, TE 30, 1.5 T) at a mean interval of 2.5 years in 36 relapsing-remitting (RR) MS patients: 19 had been treated with AZA, beside steroids after relapses (AZA group), and 17 had been treated with steroids only (control group). All but 3 patients were in the early phase of the disease. Total lesion area (TLA) was measured by manual outlining method and the arbitrary score proposed by Ormerod (total score) was also calculated from the number and diameter of lesions. Lesion load was the same at baseline, but median percentage difference of TLA between first and second scan was + 15.6% in control, -43.7% in the AZA group (p < 0.05, Mann-Whitney test). The distribution of patients according to TLA change, assuming that an increase or decrease was significant if larger than 50%, was found to be significantly different in favor of AZA-treated patients (chi(2) = 35.92, p < 0.001). These results suggest an effect of AZA treatment on MRI lesion load in early RR MS: a larger prospective study is worthwhile.

[Phonorhinorheometric study and laryngeal sonography in subjects affected by velopharyngeal insufficiency]

The aim of the present study was to evaluate the validity of combining two non invasive diagnostic approaches, (photorhinorheometry and sonography) in order study phonatory pathology in subjects suffering from velopharyngeal insufficiency (VPI). Twenty-six patients with nasal air escape during phonation and/or hyperrhinophonia due to to VPI were evaluated employing both methods. Phonorhinorheometry permitted air escape through the nasal cavities during phonation to be evaluated. Compartmentalization of the pharyngeal and nasal resonators during phonation was measured through MCF (maximal consonantic flow) values and MCV (mean consonantic volume), both normalized to the intensity of sound emission during the consonatic phases of speech. Sonography gave information concerning the phonema of resonance and articulation: a modification of the method, which also permitted sound production through an electroacoustic transductor kept in contact with the prelaryngeal skin, was made. This reduced intrinsic noise and increased dynamic modulations of the resonators of the vocal tract. Comparison between sonographic recordings obtained through a standard microphone and skin transducer permitted evaluation of influence of the vocal tract above the glottis on the phonatory process. In particular, recordings had by skin transducers showed a wider amplitude display and a better identification of vocal attack. Phonorhinorheometry and sonography are useful objective and non-invasive tools in evaluating phonatory pathology in patients suffering from VPI and in monitoring therapeutic approaches.

Prevalence of lupus anticoagulant in patients with cirrhosis: relationship with beta-2-glycoprotein I plasma levels

We have previously demonstrated that patients with cirrhosis may be positive for lupus anticoagulant and anticardiolipin antibodies. The prevalence and clinical value of antiphospholipid antibodies in cirrhosis have never been described. Besides, it has not yet been determined if serum levels of beta-2-glycoprotein I, which is synthesized by the liver and mediates the interaction between cardiolipin and anticardiolipin antibodies affects lupus anticoagulant detectability in cirrhosis. We evaluated the prevalence of lupus anticoagulant in 63 patients with cirrhosis and related it to beta-2-glycoprotein I serum levels. We also analyzed whether lupus anticoagulant and anticardiolipin antibodies were associated with previous thrombotic complications. Eleven patients (18%) were lupus anticoagulant positive; 14 (22%) had high values of anticardiolipin antibodies. Fourteen patients had a previous history of splanchnic venous thrombosis (n = 9) or thrombophlebitis (n = 5). A significant association between lupus anticoagulant (p = 0.0001), anticardiolipin antibodies (p = 0.0001) and venous thrombosis was found. Patients with severe liver failure had significantly lower beta-2-glycoprotein I levels than those with moderate (p < 0.01) or low (p < 0.001) hepatic insufficiency. Among 14 anticardiolipin antibodies positive patients, six with severe liver failure were lupus anticoagulant negative and had beta-2-glycoprotein I values below 100 micrograms/ml. In four of these, basal values of dilute activated partial thromboplastin time were not modified by the addition of 50 micrograms/ml of exogenous beta-2-glycoprotein I. This study shows that antiphospholipid antibodies are relatively frequent in cirrhosis and that beta-2-glycoprotein I levels are not so low as to affect lupus anticoagulant detectability.(ABSTRACT TRUNCATED AT 250 WORDS)

Cutaneous circulation in Raynaud's phenomenon during emotional stress. A morphological and functional study using capillaroscopy and laser-Doppler

In order to assess the effects of emotional stress on the cutaneous microcirculation in patients suffering from Raynaud's phenomenon (RP) a group of 18 patients with this pathology and 16 healthy control subjects underwent an "arithmetical test". The microcirculatory response was examined using a laser Doppler apparatus. The results obtained showed a constantly reduced flow during mental stress in normal subjects; in the RP group it was possible to observe: a first subgroup with a reduced flow similar to that seen in normal subjects, and a second subgroup with a paradoxically increased flow. It is likely that the normal vasoconstrictor response is the expression of the functional impairment of the microcirculation alone (primary RP), whereas vasodilatation in response to mental stress is a sign, of the organic development of the disease right from an early stage.

Differential control of in-phase and anti-phase coupling of rhythmic movements of ipsilateral hand and foot

Rhythmic flexion-extensions of ipsilateral hand and foot are easily performed ("easy" association) when the two segments are moved in phase (isodirectionally), whereas great care and attention are required ("difficult" association) to move them in phase opposition. We searched for features distinguishing the two types of coupling by analyzing, on ten subjects: 1) the frequency limit in each association; and, 2) if coupling is modified by inertial or elastic loading of the hand. 1) Subjects were asked to oscillate hand and foot at various paced frequencies, in the easy or in the difficult association for one minute at least. In the easy coupling, the task was performed up to 2.0-2.5 Hz, the duration being thereafter shortened by muscular fatigue. In the difficult coupling when the frequency was increased above 0.7-1.7 Hz, the performance rapidly shortened, not because of fatigue but because of an inevitable reversal to the in-phase movement. The frequency-duration curve always followed a similar decay, although it covered different frequency ranges in the various subjects. 2) The effect of charging the hand with inertial or elastic loads was studied at the subject's preferred frequency, chosen when the hand was unloaded. Without loading, in the easy association the hand cycle slightly lagged the foot cycle while in the difficult one an almost perfect phase opposition was maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of transmastoid electrical stimulation on the triceps brachii EMG in man

Transmastoid galvanic stimulation was applied to five subjects while records were taken of the rectified and averaged EMG from the triceps brachii of both sides. In four subjects current pulses of 1.6 mA, lasting 10-100 ms, evoked an excitatory response with a latency of 30-35 ms from the side ipsilateral to the anode and inhibition appeared at 40 ms on the side ipsilateral to the cathode. In the fifth subject the stimulus evoked inhibition at 40 ms on both sides. Thresholds for both excitatory and inhibitory responses were between 0.6 and 1 mA. Control experiments excluded a possible cutaneous origin. These actions might therefore represent reflex responses elicited by activation of the vestibular systems.