Critical active-site residues identified by site-directed mutagenesis in Pseudomonas aeruginosa phosphorylcholine phosphatase, a new member of the haloacid dehalogenases hydrolase superfamily.

Pseudomonas aeruginosa phosphorylcholine phosphatase (PChP), the product of the PA5292 gene, is synthesized when the bacteria are grown with choline, betaine, dimethylglycine, or carnitine. In the presence of Mg(2+), PChP catalyzes the hydrolysis of both phosphorylcholine (PCh) and p-nitrophenylphosphate (p-NPP). PCh saturation curve analysis of the enzyme with or without the signal peptide indicated that the peptide was the fundamental factor responsible for decreasing the affinity of the second site of PChP for PCh, either at pH 5.

DNA conformational changes and cleavage by ruthenium(II) nitrofurylsemicarbazone complexes.

Metal complexes that establish interactions with DNA are being studied not only because of their potential use as therapeutic agents but also as tools for biochemistry and molecular biology. Searching for drugs with anti-trypanosome activity, we previously synthesized a series of ruthenium mixed ligand dimethyl sulfoxide complexes of the type [Ru(II)Cl(2)(DMSO)(2)L], where L is 5-nitrofurylsemicarbazone derivatives and DMSO is dimethyl sulfoxide. Though they present the ability to bind DNA, no activity against parasites in cell culture was observed.

[Research on sexually transmitted infections in asymptomatic heterosexual males whose partners have cervical intraepithelial neoplasia].

Introduction: Human papillomaviruses (HPV) are the etiological agents of genital warts and of cervical intraepithelial neoplasia (CIN), and they are sexually transmitted. The aim of this study is to determine the prevalence of sexually transmitted infections (STI) in asymptomatic heterosexual males who consult their physicians seeking advice after their partners have been diagnosed with CIN.

Methods: 181 asymptomatic males whose partners were women diagnosed with CIN were studied at the STI unit in Gijón over a five-year period (1999-2003).

Carboxyphenyl metalloporphyrins as photosensitizers of semiconductor film electrodes. A study of the effect of different central metals.

Free-base (P), Zn(II) (P(Zn)), Cu(II) (P(Cu)), Pd(II) (P(Pd)), Ni(II) (P(Ni)), and Co(II) (P(Co)) 5-(4-carboxyphenyl)-10,15,20-tris(4-methylphenyl) porphyrins were designed and synthesized to be employed as spectral senzitizers in photoelectrochemical cells. The dyes were studied adsorbed on SnO(2) nanocrystalline semiconductor and also in Langmuir-Blodgett film ITO electrodes in order to disclose the effect of molecular packing on the studied properties. Electron injection yields were obtained by fluorescence quenching analysis comparing with the dyes adsorbed on a SiO(2) nanocrystalline insulator.

Nitrofurylsemicarbazone rhenium and ruthenium complexes as anti-trypanosomal agents.

Rhenium and ruthenium complexes of the type [Re(V)OCl(2)(PPh(3))L] and [Ru(II)Cl(2)(DMSO)(2)L], where L are 5-nitrofurylsemicarbazone derivatives, were prepared in an effort to obtain new anti-trypanosomal agents combining the recognized biological activity of these metals and the trypanocidal activity of the free ligands. Rhenium complexes resulted unstable in aqueous solution not allowing their use as potential drugs. On the other hand, complexation to ruthenium of the bioactive ligands lead to the lack of antiprotozoa activity even though free radical production and redox cycling induction were detected when the compounds were incubated in presence of Trypanosoma cruzi cells.

Conductance of a biomolecular wire.

Carotenoids (Car) act as "wires" that discharge unwanted electrons in the reaction center of higher plants. One step in this "side-path" electron conduction is thought to be mediated by Car oxidation. We have carried out direct measurements of the conductance of single-Car molecules under potential control in a membrane-mimicking environment, and we found that when Car are oxidized conductance is enhanced and the electronic decay constant (beta) is decreased.

Novel antitrypanosomal agents based on palladium nitrofurylthiosemicarbazone complexes: DNA and redox metabolism as potential therapeutic targets.

In the search for new therapeutic tools against American Trypanosomiasis palladium complexes with bioactive nitrofuran-containing thiosemicarbazones as ligands were obtained. Sixteen novel palladium (II) complexes with the formulas [PdCl2(HL)] and [Pd(L)2] were synthesized, and the crystal structure of [Pd(5-nitrofuryl-3-acroleine thiosemicarbazone)2] x 3DMSO was solved by X-ray diffraction methods. Most complexes showed higher in vitro growth inhibition activity against Trypanosoma cruzi than the standard drug Nifurtimox.

Electrochemical and ESR study of 5-nitrofuryl-containing thiosemicarbazones antiprotozoal drugs.

Cyclic voltammetry and electron spin resonance (ESR) techniques were used in the investigation of several potential antiprotozoal thiosemicarbazones nitrofurane derivatives. A self-protonation process involving the protonation of the nitro group due to the presence of an acidic proton in the thiosemicarbazone moiety was observed in the first step of a CEE(rev) reduction mechanism of these derivatives. ESR spectra of the free radicals obtained by electrolytic reduction were characterized and analyzed.

[Care according to diabetes patients and their main caregivers].

This case study aims to describe how diabetes patients and their main caregivers perceive the difficulties faced to control the disease. Data were collected through audio records made at the Nursing Education Center for Adults and Elderly in April 2003 and submitted to thematic content analysis. The following themes emerged from the analysis: dietary transgressions, medication-related problems and interpersonal influences.

Liquid water-ice I phase diagrams under high pressure: sodium chloride and sucrose models for food systems.

The knowledge of high pressure and low temperature phase diagrams of aqueous systems is required in fields such as food sciences, biology, cryo-microscopy and geology, to reduce processing costs, improve treatments results or advance in physical phenomena understanding. The phase transition curve between liquid water and ice I for sucrose and sodium chloride solutions has been obtained for concentrations ranging from 16% to 36% and from 1.63% to 16.

Sarcoptes scabiei in a sexually transmitted infections unit: a 15-year study.

Background: Few epidemiologic studies of scabies in sexually transmitted infection (STI) unit attenders exist.

Goal: The goal of this study was to determine epidemiology and trends of infestation among attenders at a Spanish STI unit.

Study: A prospective 15-year (1988-2002) study was conducted of 9751 STI unit attenders, investigating scabies and other STIs.

Variation of microbiological and biochemical parameters in the faeces of two healthy people over a 15 day period.

Background: Recent years have seen increasing interest in the complex microbial ecosystem of the human gastrointestinal tract. Knowledge of its microbial colonists and their beneficial/detrimental activities is important. However, generalized assumptions about the microbial composition of the human gut should be taken with caution until more studies in different human communities have been conducted.

[Up to date in sexually transmitted infections: epidemiology, diagnostic approaches and treatments].

In the last years, there have been important advances in sexually transmitted infections such as genome sequencing of Treponema pallidum, Chlamydia trachomatis or Mycoplasma genitalium; the new taxonomic position of Calymmatobacterium granulomatis; commercial diagnostic systems based on nucleic acid amplification; the emergence of quinolone resistance in Neisseria gonorrhoeae; new therapeutic approaches in vulvovaginal candidiasis that include boric acid; the demonstration that valacyclovir reduces the risk of transmission of genital herpes or the availability of immune-response modifier in the treatment of genital warts, and that are questions in the goal of this review. Viral hepatitis and HIV were no reviewed by space reasons.

In vitro activity and mechanism of action against the protozoan parasite Trypanosoma cruzi of 5-nitrofuryl containing thiosemicarbazones.

The in vitro growth inhibition activity of new thiosemicarbazone derivatives against the protozoan parasite Trypanosoma cruzi, the causative agent of American trypanosomiasis, are described. The designed compounds combine in the same molecule the thiosemicarbazone function, recently described as a potent cruzain-inhibitor moiety, and the recognised 5-nitrofuryl group, an oxidative stress promoter. Some of the derivatives were found to be very active against the cultured (epimastigote) form of the parasite, being 1.

Ruthenium (II) nitrofurylsemicarbazone complexes: new DNA binding agents.

Complexes of the type [Ru(II)Cl(2)(DMSO)(2)L], where L are 5-nitrofurylsemicarbazone derivatives, were prepared in an effort to combine the potential anti-tumor activity of the metal and the free ligands. The new complexes are excellent DNA binding agents for calf thymus DNA. So, their in vitro anti-tumor activity was tested in cellular models and the complexes were found to be non-cytotoxic on the tumor cell lines assayed, neither in aerobic conditions nor in the bio-reductive assay performed.

Ice VI freezing of meat: supercooling and ultrastructural studies.

While "classical" freezing (to ice I) is disruptive to the microstructure of meat, freezing to ice VI has been found to preserve it. Ice VI freeze-substitution microscopy showed no traces of structural alteration on muscle fibres compared with the extensive damage caused by ice I freezing. The different signs of the freezing volume changes associated with these two ice phases is the most likely explanation for the above effects.

Detection of Iberian ham aroma by a semiconductor multisensorial system.

A semiconductor multisensorial system, based on tin oxide, to control the quality of dry-cured Iberian hams is described. Two types of ham (submitted to different drying temperatures) were selected. Good responses were obtained from the 12 elements forming the multisensor for different operating temperatures.

Molecular characterization of ciprofloxacin resistance of gonococcal strains in Spain.

Background: Over the past several years, the emergence of gonococcal isolates with intermediate or full resistance to fluoroquinolones has become a significant concern in several countries, including Spain.

Goal: The goal was to determine the occurrence of ciprofloxacin resistance among Neisseria gonorrhoeae strains in Spain during 2000 to 2001 and determine the frequency and patterns of mutations at gyrA, gyrB, and parC genes in these isolates.

Study Design: Eleven ciprofloxacin-resistant strains (with MICs ranging from 1 to 64 micrograms/mL) and two intermediate isolates (with MICs of 0.

Phthirus pubis in a sexually transmitted diseases unit: a study of 14 years.

Background: There have been few epidemiologic studies of pubic lice in recent times, and the exact incidence is unknown.

Goal: The goal was to determine the trends of pubic lice infestation in a risk group of males and female prostitutes in an STD unit in Spain.

Study Design: This was a prospective 14-year study, from 1988 to 2001, of all patients attending the STD unit in Gijón (Asturias, Spain), investigating crab lice and other STDs.

Trends in the prevalence of pathogens causing urethritis in Asturias, Spain, 1989-2000.

Background: There are few studies of recent trends in the etiology and epidemiologic characteristics of specific microorganisms causing urethritis in men.

Goal: The objective of the current study was to show the clinical experience in our country and to evaluate the trends in the prevalence of the pathogens in male urethritis, as well as the epidemiologic patterns in a series of 2101 patients.

Study Design: This was a descriptive study of the etiological agents causing urethritis in our sexually transmitted disease clinics in a period of 12 years (1989-2000), with a comparison of two periods of time.

Active transport of Ca2+ by an artificial photosynthetic membrane.

Transport of calcium ions across membranes and against a thermodynamic gradient is essential to many biological processes, including muscle contraction, the citric acid cycle, glycogen metabolism, release of neurotransmitters, vision, biological signal transduction and immune response. Synthetic systems that transport metal ions across lipid or liquid membranes are well known, and in some cases light has been used to facilitate transport. Typically, a carrier molecule located in a symmetric membrane binds the ion from aqueous solution on one side and releases it on the other.

Cytogenetic analysis of 100 consecutive newly diagnosed cases of acute lymphoblastic leukemia in Rio de Janeiro.

We report the cytogenetic analysis of newly diagnosed Brazilian children with acute lymphocytic leukemia (ALL). We investigated 100 ALL cases from four different institutions in Rio de Janeiro. The frequency of chromosomal abnormalities was 92.