Gene therapy for liver diseases: recent strategies for treatment of viral hepatitis and liver malignancies

Gene therapy has emerged as a powerful and very plastic tool to regulate biological functions in diseased tissues with application in virtually all medical fields. An increasing number of experimental and clinical studies underline the importance of genes as curative agents in the future. However, intense research is needed to evaluate the potential of gene therapy to improve efficacy and minimise the toxicity of the procedure.

Molecular modelling of the differential interaction between several non-steroidal anti-inflammatory drugs and human prostaglandin endoperoxide H synthase-2 (h-PGHS-2)

The prostaglandin endoperoxide H synthase-1 (PGHS-1) and prostaglandin endoperoxide H synthase-2 (PGHS-2) are the targets of non-steroidal anti-inflammatory drugs (NSAIDs). The high degree of selectivity for inhibition of PGHS-2 shown by certain compounds appears to stem from two mechanisms (time-dependent, time-independent inhibition) by which they interact with each isoform. Molecular models of the complexes between indomethacin, fenamates, 2-phenylpropionic acids and the selective cyclooxygenase-2 (COX-2) inhibitors, with the cyclooxygenase active site of human PGHS-2 have been built by combining homology modelling, conformational searching and automated docking techniques. The stability of the resulting complexes has been assessed by molecular dynamics simulations combined with extended linear response calculations. The results allow us to identify regions of biological significance consistent with both X-ray crystallographic and kinetic results. The selective PGHS-2 inhibitors exploit the extra space of a side-pocket in the active site of PGHS-2 that is not found in PGHS-1. The results obtained point out a marked relationship between the experimental affinity and the electrostatic interaction energy alone for a series of NSAIDs. Analysis of the structural and the energetic data provides evidence supporting that network of hydrogen bonds between Tyr355, Glu524, Arg120 and Arg513 might be involved in mediating the binding of the time-dependent inhibitors of PGHS-2.

["MODY" diabetes. Beyond a monogenic disease]

Maturity Onset Diabetes of the Young is a particular form of type 2 diabetes, classically defined by an autosomal dominant inheritance, a young age at diagnosis (before 25 years) and an insulin secretion defect. At this time, six MODY genes have been described. Beyond the apparent simplicity, the study of such monogenic model of disease may help us to approach a complex disease such as type 2 diabetes, where is involved to conserve a genetic and environmental factors network. This different approach may help us to better understand type 2 diabetes physiopathology.

[Therapeutic strategies in type 2 diabetes]

UKPDS and DCCT studies have demonstrated the critical role of tight glycaemic control to reduce the micro- and macro-vascular damage linked to diabetes. Unfortunately, the insulin requirement of type 2 diabetic patients remains elevated since 5 to 7% of these patients will required, yearly, a change from oral antidiabetic drug to insulin treatment to maintain a good glycaemic control. This manuscript is intended to review the currently available oral antidiabetic drugs, their benefits as well as potential arms and to propose a simplified therapeutic strategy in presence of type 2 diabetes.

[Diabetic nephropathies: therapeutic aspects]

The incidence of diabetic nephropathy has declined these last decades, but diabetes mellitus still remains the commonest cause of end-stage renal failure, due to an increased prevalence of diabetes mellitus and a longer life expectancy for diabetic patients. The aim of this review is to describe the natural history of diabetic nephropathy and discuss the influence of many factors such as genetic and non-genetic progression promoters, hypertension, hyperglycemia, dyslipidemia, proteinuria and tobacco. Because only a comprehensive treatment strategy of these promoters will reduce the risk of end-stage renal failure, the inclusion of cardiovascular risk factors management and the screening of cardiovascular disease will further contribute to reduce the very high mortality of diabetic patients suffering of diabetic nephropathy.

[Diabetic foot: a public health problem too often underestimated. Consequences and therapeutic possibilities]

The clinical screening of diabetic patients at risk for foot ulcer should be regularly performed by all physicians and health professionals in charge of these patients. In addition, the high risk patient should be also educated to detect high risk foot lesions. This step represents the first strategy in order to prevent this too frequent complication of diabetes mellitus. The amputation which represents the most dramatic evolution of foot ulcer, has profound psychosocial, economic and functional effects on diabetic patients. For these reasons a global strategy should be developed in order to reduce the incidence of diabetic foot ulcer. A systematic follow-up strategy in high risk patients is highly recommended. The patient education is one of the most important step for the success of this strategy.

Decreased invasive capacity of quinolone-resistant Escherichia coli in patients with urinary tract infections

Quinolone-resistant (QR) Escherichia coli may have lower invasive capacity than does quinolone-susceptible E. coli. To evaluate this, we prospectively collected data regarding all cases of E. coli invasive urinary tract infections (IUTI) in 669 adults admitted to the Infectious Diseases Unit of our hospital during a 3-year period, as well as 10,950 patients with cystitis or asymptomatic bacteriuria who presented to the outpatient clinic during a 1-year period. QR E. coli was isolated in 20% of patients with cystitis, compared with 8% of those with IUTI (P<.05). The proportion of E. coli isolates that were quinolone resistant was similar in patients with bacteremic and nonbacteremic IUTI. The factors of urinary manipulation and structural abnormalities were independently associated with the presence of quinolone resistance. Old age was the only variable independently associated with blood invasion. QR E. coli is less likely to produce invasive disease (pyelonephritis and prostatitis) than is quinolone-susceptible E. coli. However, once pyelonephritis or prostatitis have developed, there is no difference in the incidence of bacteremia.

New device for direct extraction of volatiles in solid samples using SPME

A new device that allows extraction of volatiles from solid materials by SPME, avoiding preparation of the sample, was designed and tested in two different food products. Volatiles from dry-cured ham and canned liver sausage were analyzed by headspace SPME (HS SPME) and by using a new device that protects the SPME fiber in the core of the solid material. Volatile profiles generated by using both methods of extraction were very similar in both products. Compounds that have been previously highlighted as quality markers, such as products from oxidative degradation of lipids, products from Strecker degradation of amino acids, or terpenes, were satisfactorily extracted by SPME coupled to the device for direct extraction. In addition, by using this method no laboratory contaminants were extracted, whereas some major laboratory solvents were presented in the chromatogram using the HS SPME method. However, coefficients of variation were higher when performing the direct sampling procedure. This new device appears to have potential as a simple method for extracting volatiles in solid materials while at the same time avoiding taking samples.

Fungemia due to Scedosporium prolificans: a description of two cases with fatal outcome

Two cases, probably related, of fungemia due to Scedosporium prolificans are described in two patients with acute leukemia. Both were admitted to the hematological ward in nearby rooms, during building work in the hospital. After a previous bacterial sepsis in the neutropenic phase, which improved with antibiotic treatment, the respiratory status in both patients deteriorated presenting acute dypsnea, with a lung infiltrate in one of them. A few hours later both patients died. Blood cultures were positive for S. prolificans. These two new cases of S. prolificans infection stress the importance of awareness of this emerging pathogen in patients who suffer a hematologic malignancy during the neutropenic phase, especially if building work is taking place in the hospital.

New approach to the chemistry of polysulfides using diphosphanylmethanide complexes of manganese(I)

The study of the nucleophilic degradation of S8 by the methanide complex [Mn(CO)4[(PPh2)2CH]] (2) has led to the preparation of a unique class of polysulfide derivatives of formula [(CO)4Mn[(PPh2)2C-Sn-C(PPh2)2]-Mn(CO)4]. The structures of 3 (n = 6), 4 (n = 2), and 7 (n = 1) have been determined by X-ray crystallography, whereas those polysulfides with the sulfur chains S7, S5, S4, and S3 have been detected by spectroscopic methods. The polysulfides with n > 2 lose sulfur spontaneously, a process that can be accelerated by treatment with PPh3 or Na/Hg. Complexes 3, 4, and 7 were protonated at the two methanide carbon atoms to give the cationic dinuclear derivatives [(CO)4Mn[(PPh2)2C(H)-Sn-C(H)-(PPh2)2]Mn(CO)4]2+ (8, n=6; 9, n=2; 10, n = 1). The 1H NMR spectrum of 9 suggests the existence of intramolecular C-H...S interactions, in agreement with the X-ray structural determination of this complex. By treatment of 4 and 7 with one equivalent of HBF4 it is possible to selectively protonate just one methanide carbon atom, which allows the isolation of the mixed cationic derivatives R(CO)4Mn[(PPh2)2C(H)-Sn-C(PPh2)2]Mn(CO)4]+ (11, n = 2; 6, n = 1). Additionally, heterometallic complexes containing a bridging disulfide unit, of general formula [(CO)4Mn[(PPh2)2C(AuPPh3)S-SC-(AuPPh3)(PPh2)2]Mn(CO)4]2+ (12) and [(CO)4Mn[(PPh2)2C(H)S-SC(AuPPh3)-(PPh2)2]Mn(CO)4]+ (13), were prepared by reaction of 4 and 11, respectively, with [AuCl(PPh3)] in the presence of TlPF6.

Synthesis and reactivity of bridging and terminal hydrosulfido palladium and platinum complexes. Crystal structures of [NBu4]2[(Pt(c6F5)2(mu-SH)]2], [Pt(C6F5)2(PPh3)[S(H)AgPPh3]], and [Pt(C6F5)2(PPh3)[S(AuPPh3)2]]

The reactions of the hydroxo complexes [M(2)R(4)(mu-OH)(2)](2)(-) (M = Pd, R = C(6)F(5), C(6)Cl(5); M = Pt, R = C(6)F(5)), [[PdR(PPh(3))(mu-OH)](2)] (R = C(6)F(5), C(6)Cl(5)), and [[Pt(C(6)F(5))(2)](2)(mu-OH)(mu-pz)](2-) (pz = pyrazolate) with H(2)S yield the corresponding hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-), [[PdR(PPh(3))(mu-SH)](2)], and [[Pt(C(6)F(5))(2)](2)(mu-SH)(mu-pz)](2-), respectively. The monomeric hydrosulfido complexes [M(C(6)F(5))(2)(SH)(PPh(3))](-) (M = Pd, Pt) have been prepared by reactions of the corresponding binuclear hydrosulfido complexes [M(2)(C(6)F(5))(4)(mu-SH)(2)](2-) with PPh(3) in the molar ratio 1:2, and they can be used as metalloligands toward Ag(PPh(3))(+) to form the heterodinuclear complex [(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and toward Au(PPh(3))(+) yielding the heterotrinuclear complexes [M(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]]. The crystal structures of [NBu(4)](2)[[Pt(C(6)F(5))(2)(mu-SH)](2)], [Pt(C(6)F(5))(2)(PPh(3))[S(H)AgPPh(3)]], and [Pt(C(6)F(5))(2)(PPh(3))[S(AuPPh(3))(2)]] have been established by X-ray diffraction and show no short metal-metal interactions between the metallic centers.

Gold nanoparticles containing redox-active supramolecular dendrons that recognize H2PO4-

Gold nanoparticles have been functionalized with thiol dendrons containing three redox active amidoferrocenyl or silylferrocenyl units; using cyclic voltammetry, these dendronized gold nanoparticles recognize H2PO4-.

Protection against woodchuck hepatitis virus (WHV) infection by gene gun coimmunization with WHV core and interleukin-12

Woodchuck hepatitis virus (WHV) and hepatitis B virus (HBV) are closely similar with respect to genomic organization, host antiviral responses, and pathobiology of the infection. T-cell immunity against viral nucleocapsid (HBcAg or WHcAg) has been shown to play a critical role in viral clearance and protection against infection. Here we show that vaccination of healthy woodchucks by gene gun bombardment with a plasmid coding for WHcAg (pCw) stimulates proliferation of WHcAg-specific T cells but that these cells do not produce significant levels of gamma interferon (IFN-gamma) upon antigen stimulation. In addition, animals vaccinated with pCw alone were not protected against WHV inoculation. In order to induce a Th1 cytokine response, another group of woodchucks was immunized with pCw together with another plasmid coding for woodchuck interleukin-12 (IL-12). These animals exhibited WHcAg-specific T-cell proliferation with high IFN-gamma production and were protected against challenge with WHV, showing no viremia or low-level transient viremia after WHV inoculation. In conclusion, gene gun immunization with WHV core generates a non-Th1 type of response which does not protect against experimental infection. However, steering the immune response to a Th1 cytokine profile by IL-12 coadministration achieves protective immunity. These data demonstrate a crucial role of Th1 responses in the control of hepadnavirus replication and suggest new approaches to inducing protection against HBV infection.

Frequency of selection of fluoroquinolone-resistant mutants of Neisseria gonorrhoeae exposed to gemifloxacin and four other quinolones

We studied the frequency of mutation of clinical isolates of Neisseria gonorrhoeae (two nalidixic acid susceptible and two nalidixic acid resistant), and the stability of the mutants obtained, in the presence of three different concentrations of five fluoroquinolones. The frequency of mutation was low for all the quinolones. Only one N. gonorrhoeae mutant, obtained with trovafloxacin at 4 x MIC presented a stable increase in the MIC of this quinolone, not attributable to novel mutation(s), both in the gyrA and parC genes, although not showing any increase in the MIC of the other quinolones tested. In summary, gemifloxacin was the only quinolone tested for which resistant mutants were not obtained.

Phosphorylation-induced activation of tilapia nonspecific cytotoxic cells by serum cytokines

Cytokines as soluble mediators of immunity are important in understanding immunological mechanisms against infectious organisms and during stress conditions. In the present study, the role of protein tyrosine phosphorylation is assessed in the activation of nonspecific cytotoxic cells (NCC) from tilapia Oreochromis niloticus by cytokine-like serum factors. NCC are the teleost equivalent of mammalian natural killer (NK) cells. In teleost fish, NCC are important mediators of innate immunity against bacterial and parasite insult and tumor growth. We have previously shown that exposure of tilapia (a tropical fish) to cold water temperatures (3 to 5 min at 5 to 10 degrees C) produces physiological stress responses characterized by immediate phenotypic and immunological changes. The serum obtained from stressed tilapia contains a 'stress activating serum factor' (SASF) which passively increases in vitro naive NCC cytotoxicity 2- to 4-fold over control levels. In an effort to identify the mechanisms of activation of cytotoxicity by SASF, the phosphorylation status of tyrosine residues in proteins from treated NCC was determined. NCC were incubated with heat-inactivated or untreated stress serum and Western blots of the cell lysates were probed with anti-phosphotyrosine monoclonal antibodies (mabs). The levels of tyrosine phosphorylation in several proteins of the SASF-activated NCC were higher than in control cells. Increased tyrosine phosphorylation was also induced by incubation of NCC in the presence of the tyrosine phosphatase inhibitor Na orthovanadate (vanadate). In every case, an increase in phosphorylation status shown by Western blotting was correlated with increases in cytotoxic activity of NCC against HL-60 target cells. The enzyme inhibitor Herbimycin A (HA) has been previously used to inhibit the activity of the src-family of tyrosine kinases. In the present study, a 4 h pretreatment of NCC with HA (2 microM), followed by treatment with SASF blocked the activation of cytotoxicity produced by SASF. These results suggested that activation of NCC by cytokine-like factors is mediated through activation of the src family of protein tyrosine kinases. Activation was associated with increased phosphorylation and higher cytotoxic effector functions.

[Oral anti-diabetic agents: update]

Type 2 diabetes mellitus is one component of the metabolic syndrome. The treatment of the metabolic syndrome includes the control of hyperglycaemia, which represents one aspect of the management of this complex disease. Indeed, the intensive treatment of hyperglycaemia is clearly associated with the prevention of the micro- and macro-vascular complications. This review describes how to use oral antidiabetic agents: sulfonylurea, glinide, biguanide, alpha-glucosidase inhibitors and glitazone.

Characterization of sparfloxacin-resistant mutants of Staphylococcus aureus obtained in vitro

A sparfloxacin-susceptible clinical isolate of Staphylococcus aureus was grown in increased concentrations of sparfoxacin. The presence of mutations in gyrA, gyrB, grlA and grlB genes was analyzed. The primary point mutation was located in the gyrA gene (Glu-88 to Lys). Two further mutation steps appeared in the amino acid change Ser-80 to Tyr in GrlA. No mutations occurred in the gyrB or grlB genes. Efflux pumps involved in the increase of resistance were also found to affect norfloxacin and ciprofloxacin. This effect may be related to NorA. An overexpression of NorA, may be associated with the increase of the MIC of norfloxacin from 32 mg/l to >200 mg/l in the final mutant. The MICs levels of sparfloxacin were affected by unknown mechanism.

[Nosocomial fungemias in a general hospital. Epidemiology and prognostic factors. Prospective study 1993-1998]

BACKGROUND

Nosocomial fungemias are infections with a high mortality rate. In last years the incidence of these infections has increased probably because of the growing population of immunocompromised patients who undergo aggressive diagnostic and therapeutic techniques.

OBJECTIVE

To know the epidemiologic characteristics, risk factors, clinical features and prognosis of fungemia.

PATIENTS AND METHODS

We prospectively evaluated all the patients with proven fungemia in our center during a 5 year-period. After finishing antifungal treatment a minimum follow-up of 1 month was carried out. Fungal isolation and identification were performed by standard tests.

RESULTS

During the period of study we evaluated 81 patients with an episode of nosocomial fungemia. Global incidence was 0,9 episodes per thousand admitted patients. Candida albicans was the more frequently isolated species (n=53), followed by C. parapsilosis (n=11), C. tropicalis (n=6) and C. glabrata (n=5). Most of the patients had a central intravenous line and were on parenteral nutrition therapy. All of them previously received at least one course of broad-spectrum antibiotics. Overall mortality was 49,6%. A worst prognosis was significantly associated with: age over 65 years, surgical procedures during present admission, leucocytosis, shock, and delay in antifungal treatment.

CONCLUSIONS

Fungal bloodstream infection incidence is high in our environment. It is associated with a high mortality rate, specially in patients in whom the beginning of antifungal treatment was delayed. A higher clinical suspicion index may improve the poor outcome in these patients.

The stability against freezing of an internal liquid-water ocean in Callisto

The discovery of the induced magnetic field of Callisto-one of Jupiter's moons-has been interpreted as evidence for a subsurface ocean, even though the presence of such an ocean is difficult to understand in the context of existing theoretical models. Tidal heating should not be significant for Callisto, and, in the absence of such heating, it is difficult to see how this internal ocean could have survived until today without freezing. Previous work indicated that an outer ice layer on the ocean would be unstable against solid-state convection, which once begun would lead to total freezing of liquid water in about 108 years. Here I show that when a methodology for more physically reasonable water ice viscosities (that is, stress-dependent non-newtonian viscosities, rather than the stress-independent newtonian viscosities considered previously) is adopted, the outer ice shell becomes stable against convection. This implies that a subsurface ocean could have survived up to the present, without the need for invoking antifreeze substances or other special conditions.

Osmotic properties of internally perfused barnacle muscle cells. I. Isosmotic conditions

Barnacle muscle cells regulate their volume when exposed to anisotonic conditions. Due to their large size, these cells can be internally perfused. Interestingly, perfused cells maintain their volume regulatory properties (17,21). Thus, the osmotic properties of barnacle muscle cells can be studied under conditions in which the intracellular and extracellular osmolalities, the membrane potential (V(M)), the cell volume and the intracellular pressure can all be measured simultaneously. In this manuscript we report the effect that various rates of isosmotic (1000 mOsm x kg H2O(-1)) intracellular perfusion have on cell volume, intracellular pressure, intracellular osmolality, V(M), and the apparent sarcolemmal hydraulic water permeability (L'p). Replacement of the cytosol with the perfusate at a perfusion rate of 0.83 microl x min(-1) took 120 min. During this transition period, the cell volume increased from 45.1+/-6.9 microl to 73.7+/-5.8 microl, the intracellular osmolality decreased from 1406+/-133 to 1188+/-64 mOsm x kg H2O(-1), and the intracellular pressure underwent a transient drop of 2.8 cm H2O. After 2.5 hr of continuous perfusion at 0.83 microl min(-1), the above mentioned parameters reached steady values: the L'p was 1.35 x 10(-5) cm x sec(-1) x Osm(-1) x kg H2O(-1); cell volume was 67.2+/-6 microl; the intracellular osmolality was 1052+/-10 mOsm x kg H2O(-1); the intracellular pressure was 5.6+/-0.4 cm H2O; V(M) depolarized slowly at a rate of 0.03 mV x min(-1). Stepwise increases in the rate of perfusion (from 0.83 to 3.18 microl min(-1)) produced reversible increases in the intracellular pressure, L'p and cell volume and decreases in intracellular osmolality. We conclude that intracellular perfusion: i/ produces a transient removal of intracellular osmotically active components; ii/ promotes sarcolemmal water filtration; iii/ induces a laminar flow of perfusate at the center of the cell, and iv/ enables calculations of sarcolemmal L'p values under isosmotic conditions.

[Kinetics of potassium transfer during hemodialysis]

INTRODUCTION

In order to study whether the removal of potassium in haemodialysis patients could be increased, we analyzed the kinetics of potassium transfer in the dialyzer.

METHOD

40 patients were included in the study. We studied: a) in vitro potassium exchanges between erythrocytes and plasma; b) plasma and erythrocyte potassium concentrations at dialyzer input and output; c) potassium transfers into the dialysate, using plasma clearance and direct measurement in the collected dialysate and d) erythrocyte potassium concentrations at the beginning and the end of dialysis.

RESULTS

In vitro, there is virtually no potassium transfer between erythrocytes and plasma. In vivo, erythrocyte potassium concentration is not affected by the dialyzer (98.7 +/- 6.4 mmol/l to 97.7 +/- 7.5 mmol/l, p = NS). Potassium transfer levels determined by calculated plasma clearance were similar to values obtained by measuring potassium in dialysate (0.71 +/- 0.10 mmol/min vs 0.68 +/- 0.10 mmol/min, p = NS). These results suggest that erythrocytes do not participate in potassium exchange in the dialyzer. This was confirmed by measured erythrocyte potassium concentrations, which were the same at the beginning and the end of dialysis (104.0 +/- 5.6 mmol/l vs 104.2 +/- 5.0 mmol/l, p = NS).