Metal-sulfur valence orbital interaction energies in metal-dithiolene complexes: determination of charge and overlap interaction energies by comparison of core and valence ionization energy shifts.

The electronic interactions between metals and dithiolenes are important in the biological processes of many metalloenzymes as well as in diverse chemical and material applications. Of special note is the ability of the dithiolene ligand to support metal centers in multiple coordination environments and oxidation states. To better understand the nature of metal-dithiolene electronic interactions, new capabilities in gas-phase core photoelectron spectroscopy for molecules with high sublimation temperatures have been developed and applied to a series of molecules of the type Cp(2)M(bdt) (Cp = η(5)-cyclopentadienyl, M = Ti, V, Mo, and bdt = benzenedithiolato). Comparison of the gas-phase core and valence ionization energy shifts provides a unique quantitative energy measure of valence orbital overlap interactions between the metal and the sulfur orbitals that is separated from the effects of charge redistribution. The results explain the large amount of sulfur character in the redox-active orbitals and the 'leveling' of oxidation state energies in metal-dithiolene systems. The experimentally determined orbital interaction energies reveal a previously unidentified overlap interaction of the predominantly sulfur HOMO of the bdt ligand with filled π orbitals of the Cp ligands, suggesting that direct dithiolene interactions with other ligands bound to the metal could be significant for other metal-dithiolene systems in chemistry and biology.

Hydrogen generation from weak acids: electrochemical and computational studies of a diiron hydrogenase mimic.

Extended investigation of electrocatalytic generation of dihydrogen using [(mu-1,2-benzenedithiolato)][Fe(CO)3]2 has revealed that weak acids, such as acetic acid, can be used. The catalytic reduction producing dihydrogen occurs at approximately -2 V for several carboxylic acids and phenols resulting in overpotentials of only -0.44 to -0.71 V depending on the weak acid used. This unusual catalytic reduction occurs at a potential at which the starting material, in the absence of a proton source, does not show a reduction peak. The mechanism for this process and structures for the intermediates have been discerned by electrochemical and computational analysis. These studies reveal that the catalyst is the monoanion of the starting material and an ECEC mechanism occurs.

An ovine adenovirus vector lacks transforming ability in cells that are transformed by AD5 E1A/B sequences.

Adenoviruses of the Mastadenovirus and Aviadenovirus genera are able to transform certain cell types and induce tumor formation in susceptible animals. For the mastadenoviruses the E1A/B sequences are largely responsible for these properties but E4 sequences may also be involved. The transforming sequences of the aviadenoviruses, which lack E1A/B and E4 homologues, have not yet been fully identified. The recent proposal for a third genus of adenoviruses, which apparently lack an E1A homologue and have weak E1B homology, prompted an examination of the transforming properties of ovine adenovirus OAV287 (OAV), the prototype member of the new group. When OAV and human adenovirus type 5 (Ad5) were used to infect primary rat embryo cells, transformed foci developed in Ad5- but not in OAV-infected cultures. Similarly, after plasmid transfection, baby rat kidney cells were transformed by Ad5 E1A/B but not by OAV sequences. When CSL503 cells, an ovine cell line that is permissive for OAV, were transfected with Ad5 E1A/B sequences, transformed foci again appeared. However, plasmids or fragments containing complete or partial OAV genome sequences did not detectably transform CSL503 cells under the same conditions. When Ad5 E1A/B sequences were incorporated into the complete OAV genome and transfected, transformed clones were again obtained, showing that the gene dosage and transfection conditions were not limiting for transformation. The provision of Ad5 E1A and OAV sequences in combination marginally increased the number of morphologically altered foci in baby rat kidney cells but failed to induce multilayered focus formation. The data suggest that OAV lacks transforming functions in the cell types examined. Additional information suggesting that OAV may have a fundamentally distinct strategy for replication compared with other Ads is discussed.

In vivo gene therapy for prostate cancer: preclinical evaluation of two different enzyme-directed prodrug therapy systems delivered by identical adenovirus vectors.

Advanced prostate cancer is invariably lethal once it becomes androgen independent (AI). With the aim of developing a new treatment we have used the human androgen-independent prostate cancer cell line, PC-3, to evaluate the effectiveness of two enzyme-directed prodrug therapy (EPT) systems as a novel means for promoting tumor cell destruction in vivo. We have confined our study to the use of a PSA promoter, in a preliminary attempt to achieve prostate specificity. The two EPT systems used were the HSVTK/GCV and PNP/6MPDR systems. These were chosen for their differential dependence on DNA replication for their mechanism of action. In the present work, either the HSVTK or PNP gene, each controlled by a PSA promoter fragment, was delivered by an E1-, replication-deficient human adenovirus (Ad5) into PC-3 tumors growing subcutaneously in BALB/c nude mice. Tumors were injected with a single dose of recombinant Ad5 and mice were treated intraperitoneally with the appropriate prodrug, twice daily, for 6 days thereafter. The growth of established PC-3 tumors was significantly suppressed and host survival increased with a single course of HSVTK/GCV or PNP/6MPDR treatment. HSVTK/GCV-treated PC-3 tumor growth was 80% less than that of control treatments on day 33, while PNP/6MPDR-treated tumor growth was approximately 75% less than that of control treatments on day 52. Survival data showed that 20% of HSVTK/GCV- or PNP/6MPDR-treated animals lived >45 and >448 days, respectively, longer than control animals. These results demonstrate that both HSVTK/GCV and PNP/6MPDR therapies interrupt the growth of an aggressive human prostate cancer cell line in vivo.

The role of priority programmes in the provision of health services in the state of Oaxaca, Mexico.

An assessment of the performance of five priority health programmes (basic sanitation, tuberculosis, vaccination, acute respiratory infections and acute diarrheal diseases) was carried out using ethnographic techniques in the region of La Cañada in the state of Oaxaca, Mexico. The region presents a large percentage of Indian and peasant population living in extreme poverty and health care is mainly provided by the Ministry of Health. Both characteristics of the population and the health services are used to analyze the performance of the programmes. With access to abundant resources, vaccination and diarrheal disease programmes have been highly successful in involving the population and achieving their operative targets. Consequently this capacity to concentrate resources results in a lack of resources for other programmes. Despite partial successes, all programmes face serious operational difficulties demonstrating, in turn, the lack of capacity of health services to respond to the specific demands of local populations. The information presented is relevant for the discussion of selective versus comprehensive PHC.

Primary pulmonary meningioma: report of a case and review of the literature.

Ten cases of benign primary pulmonary meningioma have been reported in the English literature. We describe herein an additional case of a benign meningioma arising in the lung showing comparable histologic features of sheets and whorls of epithelioid and meningothelial cells with numerous psammoma bodies. Immunohistochemistry showed that the tumor expressed vimentin and epithelial membrane antigen and was negative for keratin, CD34, glial fibrillary acidic protein, CAM 5.2 and S-100, in keeping with previously reported findings. Our review of the literature reveals similar clinical presentations and follow-up behavior and, where reported, similar electron microscopic and immunostaining features.

[Complementary health care models: a neglected component in the health care systems reform]. / Modelos complementarios de atención: un componente excluido en la reforma de los Sistemas de Salud.

Complementary health care models represent a neglected and scarcely studied area of the health services structure. Within them a myriad of medical therapies of various origins are included. Lately, their importance has grown by means of the increase in demand for such services, both in industrialized and developing countries. It is urgent to reinforce research in the area aiming at understanding the processes through which the population demands these services and the processes through which complementary practitioners are able to maintain their presence in a market environment where the forces of supply and demand are significant. The context created by the health services reform should be used to review the therapeutic value of these models, to promote its regulation, and to amplify the availability of therapeutic options for the population.

Relative efficiency of tumor cell killing in vitro by two enzyme-prodrug systems delivered by identical adenovirus vectors.

Enzyme-prodrug therapy for the treatment of cancer is an experimental procedure that is under intensive investigation. However, the relative merits of the various systems for use under specific conditions are still being determined. We have compared the efficacy of cell killing by the herpesvirus thymidine kinase (HSVTK)/ganciclovir and the purine nucleoside phosphorylase (PNP)/9-(beta-M-2-deoxy-erythropentofuranosyl)6-methylpurine enzyme/prodrug systems. These were chosen because of their differential dependence on DNA replication for their mechanism of action. The HSVTK and PNP genes, expressed from the identical prostate-specific antigen promoter, were transduced into human prostate and breast cancers cells using the same human adenovirus vector. The kinetics of cell killing in the presence of the respective prodrugs was monitored using a nondestructive assay that measured total cell bioactivity. The PNP/9-(beta-D-2-deoxy-erythropentofuranosyl)6-methylpurine system was clearly superior in its ability to cause cell death in vitro. Cells were killed in about half the time and at a 5-10-fold lower input of virus relative to the HSVTK/ganciclovir system. The PNP system may offer advantages for the treatment of slow-growing tumors in which the daily proliferative rate is low or in situations in which gene delivery or expression is inefficient.

Membrane binding and endoplasmic reticulum retention sequences of rotavirus VP7 are distinct: role of carboxy-terminal and other residues in membrane binding.

The sequences responsible for binding rotavirus glycoprotein VP7 to the membrane of the endoplasmic reticulum (ER) have not been identified. Here we show that the sequences which promote membrane binding in vitro are distinct from the N-terminal sequences which promote retention of VP7 in the ER in vivo. The role of the C-terminal region in membrane binding was also examined by using truncation mutants. Membrane binding in vitro was reduced but not abolished by removing up to 102 residues from the C terminus. The data suggest that the last 36 residues of VP7 may be present in the membrane or translocation pore, possibly with the C terminus protruding into the cytoplasm, since these residues contribute to, but do not account for, membrane binding. Surprisingly, modified forms of VP7 which are secreted from transfected cells showed the same membrane-binding properties in vitro as the protein retained in the ER membrane. Thus, secreted VP7 may not be present as a soluble polypeptide in the ER. A model to explain these results is presented. Previously published data are consistent with the idea that the highly conserved C terminus of nascent VP7 could have a cytoplasmic orientation which is important for assembly of mature virus particles.

Cost of diseases in Brazil: breast cancer, enteritis, cardiac valve disease and bronchopneumonia.

The results from the need to develop methodologies for performing cost analysis in developing countries, principally in the region of Latin America, were studied. It, furthermore, serves to generate knowledge from an economic evaluation in order to support decision-making related to the organization of health systems, particularly in the efficient use of resources which are allocated for the provision of medical services. Two chronic diseases (breast cancer and cardiac valve disease) and two infections (enteritis and bronchopneumonia) were selected for the study. The results recommend the use of a valid methodology for economic cost analysis of any disease to be studied and the use of this information in the decision-making process.

Massive hemoptysis in Takayasu's arteritis during pregnancy.

Takayasu's arteritis is an uncommon condition affecting predominantly young women. Because the disorder affects women in childbearing age, it may be recognized the first time during pregnancy. Various cardiovascular events may occur in the perinatal period. We describe a patient with Takayasu's arteritis who presented with massive hemoptysis. To our knowledge, this manifestation has not been documented previously.

Protective immunity to rotavirus-induced diarrhoea is passively transferred to newborn mice from naive dams vaccinated with a single dose of a recombinant adenovirus expressing rotavirus VP7sc.

VP7sc is a novel rotavirus antigen engineered for presentation at the cell surface. Several recombinant viruses were constructed in which VP7sc was inserted into the E3 region of the human type 5 adenovirus (Ad5) genome and expression and transport of the antigen was monitored in cultured 293 cells. The recombinant virus showing the greatest level of expression (Ad5/7.4) was then used to determine whether antibodies to VP7sc could be induced in a nonhuman host. BALB/c and CBA/H mice were inoculated with Ad5/7.4 by iv, ip, oral and intranasal routes and serum antibody levels were assayed by ELISA. All vaccinated animals seroconverted but, depending on the route of vaccination, not all animals showed a significant secondary response following re-inoculation. The ability of Ad5/7.4 to induce protective immunity in mice was also examined using several vaccination regimes. A single dose of Ad5/7.4 given intranasally to dams not previously exposed to rotavirus was sufficient to induce immunity which could be passively transferred to protect suckling neonates. Recombinant adenoviruses expressing protective antigens therefore may provide an alternative to the use of attenuated rotaviruses in the development of a vaccine against gastroenteritis.

Intragluteal spindle cell hemangioendothelioma. An unusual presentation of a recently described vascular neoplasm.

A 40-year-old woman noted a large tumor mass in the left buttock that, on microscopic examination, proved to be a recently described, relatively uncommon spindle cell hemangioendothelioma. This particular neoplasm, which has some features of Kaposi's sarcoma, seems not to have been reported previously in a deep, intramuscular location.

A unique case of reducing body myopathy.

The clinical, electromyographic, and histologic characteristics of a 17-year-old girl with reducing body myopathy are described. She is, to our knowledge, the oldest reported case and the only patient described with severe mitral valve prolapse and scoliosis. Electromyography demonstrated spontaneous positive sharp waves and fibrillation potentials with many low-amplitude, short, polyphasic motor unit potentials. The right deltoid muscle was characterized by focal areas with large fibers associated with increased endomysial connective tissue and "split" fibers. Purple-gray sarcoplasmic masses stained with trichrome were PAS-negative, appeared as "empty" spaces with both ATPase and NADH-TR, and stained darkly with menadione NBT. The features described expand the clinical presentation of this myopathy, and may lead to a better understanding of its etiology.

The immunogenicity of VP7, a rotavirus antigen resident in the endoplasmic reticulum, is enhanced by cell surface expression.

The glycoprotein VP7, the major serotype antigen of rotaviruses, is localized to the endoplasmic reticulum (ER) of the cell, where it is retained as a membrane-associated protein before assembly into mature virus particles. Wild-type VP7 expressed by a recombinant vaccinia virus was also located internally and was poorly antigenic. Using recombinant techniques, a correctly processed, secreted form of VP7 (S.C. Stirzaker and G.W. Both, Cell 56:741-747, 1989) was modified by addition to its C terminus of the membrane anchor and cytoplasmic domains from the influenza virus hemagglutinin. The hybrid protein was directed to the surface of cells, where it was anchored in the plasma membrane. When expressed in mice and rabbits by a recombinant vaccinia virus, the surface-anchored antigen stimulated a level of rotavirus-specific antibodies that was greater than 100-fold above the level induced by wild-type VP7. T-cell responses to the novel antigen were also elevated in comparison with the wild-type, intracellular protein. Cell surface anchoring may provide a strategy to increase the immunogenicity of intracellular antigens from other parasites and viruses.

Gas chromatographic-mass spectroscopic characterisation of the psychotomimetic indolealkylamines and their in vivo metabolites.

The use of liquid chromatography with on-line fluorescence detection has formed the basis for the separation, characterisation and quantitation of a number of metabolites of the psychotomimetic indolealkylamines N,N-dimethyltryptamine and 5-methoxy-N,N-dimethyltryptamine formed both in vitro and in vivo. Verification of the identity of metabolites has previously been facilitated by the combined use of a number of analytical techniques including multidimensional liquid chromatography and stop-flow spectroscopic analysis. We now describe the combination of liquid chromatography with gas chromatography-mass spectrometry for the unequivocal verification of a number of structurally characteristic metabolites of the psychotomimetic indolealkylamines.

In vivo metabolism of 5-methoxy-N,N-dimethyltryptamine and N,N-dimethyltryptamine in the rat.

Following intraperitoneal administration, 5-methoxy-N,N-dimethyltryptamine and N,N-dimethyltryptamine are subject to both a very rapid uptake into, and clearance from, all tissues examined. The current studies in vivo confirm previous in vitro observations that the routes involved in the metabolism of these compounds include oxidative deamination, N-demethylation, O-demethylation, and N-oxidation. The analysis of metabolic profiles in various tissues led to the identification of the N-oxides as major metabolites. The successful inhibition and redirection of metabolism away from the indole acids towards the parent compounds and their structurally unique metabolites were demonstrated in animals pretreated with iproniazid.

A source of false results in the intraoperative parathyroid density test.

A simple density test offering a valuable clue for the intraoperative differentiation of parathyroid hyperplasia from neoplasia has been described. According to the authors, if a sliver of parathyroid tissue taken from the central portion of a parathyroid gland does not sink in a mannitol solution of a defined specific gravity, it is normal. We have encountered a situation in which a sliver from the central position of an abnormal gland did not sink, thereby seemingly negating the test's utility. However, microscopic examination of the sliver revealed the reason it floated, and an additional sliver from near the surface of the same gland sank. Caution in choosing the appropriate portion of the gland to be tested is emphasized in order to avoid confusing false-negative results, or abandoning what has otherwise been a simple, fast, and accurate adjuvant intraoperative test in our laboratory.

Differential microbiological diagnosis of protothecosis from non-human sources.

Primary isolation of Prototheca was accomplished on MacConkey's, sheep blood agar, and Sabouraud dextrose agar. Prototheca was differentiated from similar organisms by its ability to grow on MacConkey's agar, and by its colonial morphology. Further differentiation was based on staining procedures to reveal the characteristic microscopic morphology. In the process of identification of several isolates of Prototheca zophii obtained from animal sources, a simple guideline for isolation and identification of these organisms was developed.