Nucleophilic epoxidation of gamma-hydroxyvinyl sulfoxide derivatives

The nucleophilic epoxidation of simple (gamma-silyloxy)vinyl sulfoxides takes place with complete stereocontrol and high yields. For substrates bearing an additional substituent at the gamma position, a reinforcing/nonreinforcing scenario is operative. While E and Z silylated substrates undergo a primarily sulfur directed epoxidation with good to excellent diastereocontrol, the related (E)-(2-methoxyethoxy)methyl ethers display diminished selectivity for the diastereomer derived from the nonreinforcing scenario.

[Lung cancer in the health care area of A Coruña (Spain): incidence, clinical approach and survival]

OBJECTIVE

To determine the incidence, clinical approach, diagnostic delay and survival for bronchogenic carcinoma (BC) in the public health area of A Coruña (Spain).

PATIENTS AND METHOD

This was a retrospective study of patients with a diagnosis of BC made in 1995 and 1996 in a health care area with 509,000 inhabitants. For analysis we gathered demographic, clinical and cyto-histologic data and analyzed diagnostic delay, extension of disease and time of death. Crude, age-specific and age-standardized incidences were calculated.

RESULTS

BC was diagnosed in 378 patients (95% men and 5% women). The crude incidence was 37 per 100,000 inhabitants (73.7 per 100,000 men and 3 per 100,000 women) and the age-standardized incidence was 21.7 per 100,000. Diagnosis was by cyto-histology in 87% of the cases, and the most frequent biopsy finding was epidermoid carcinoma. Diagnosis was by clinical or radiologic findings for 13.7%, and patients in that group were older and had greater comorbidity. No symptoms were present in 13% and in those patients diagnosis was earlier, with non-small BC predominating and 60% treated surgically. The diagnostic delay (time from the first symptom to histologic confirmation) was 2.5 months (median, 2.1), and length of delay did not affect survival. Surgery was performed in 23% of the patients with non-small BC. The median survival was 7.1 months (5.2 months for patients who were not treated surgically, and 37.6 for those who were).

CONCLUSIONS

The incidence of BC in men in our study is consistent with that reported for other Spanish regions, although the incidence we observed for women is much lower. Diagnostic delay did not affect survival. The percentage of patients with surgical-stage disease is very low and survival is very short. These findings support the need for early diagnosis.

Exogenous myristoylated-G(i2)alpha subunits of GTP-binding proteins are mitogens following their internalization by astrocytes in culture

Heterotrimeric GTP-binding proteins (G proteins) are involved in the coupling of a variety of cell surface receptors to different intracellular signalling pathways, some of which take part in the regulation of growth by affecting cell proliferation and/or differentiation. In cultured astrocytes, many receptors of neuropeptides and hormones are coupled to the heterotrimeric G(i) proteins which regulate the mitogen-activated protein kinase (MAPK/ERK) cascade through both the Galpha and Gbetagamma subunits. We have previously reported that functionally active recombinant myr-G(i2)alpha subunits added to such cultures are internalised and distributed within the plasma membrane and cytosol as well as in the nuclei of dividing astrocytes. Here we show that astrocytes proliferate dose-dependently in response to exogenous myr-G(i2)alpha subunits. Concentrations of 100 pM-30 nM myr-G(i2)alpha caused more than 2.5-fold increase of [3H]thymidine incorporation over basal levels. Other classes of myr-Galpha subunits, such as G(i3)alpha or G(o)alpha, induced a much lower proliferative effect. The addition of G(i1)alpha subunits to the cultures produced no change, indicating the selectivity of this effect. Even though myr-G(i2)alpha subunits are internalised by the cells regardless of their guanine nucleotide-bound state, much less [3H]thymidine incorporation was observed in the presence of GDPbetaS-myr-G(i2)alpha or GTPgammaS-myr-G(i2)alpha. Further, the fluorescent labelling was dissimilarly distributed, the signal being concentrated in the nucleus and perinuclear regions of the astrocytes. Selective disassembly of caveolae impaired both myr-G(i2)alpha internalisation and DNA induction. Together, these data reveal a proliferative effect of myr-G(i2)alpha subunits in astrocytes, and provide evidence for the incorporation of exogenous myr-G(i2)alpha subunits into the mitogen cascade activated by neurotransmitters or growth factors. The fact that Galpha proteins can enter cells is particularly interesting because options for delivering functional proteins into cells are limited. Thus, these proteins may have clinical applications for compensating deficits in the transduction mechanisms associated with several neurological diseases, or as a non-invasive membrane traversing carriers.

trans-Resveratrol and grape disease resistance. A dynamical study by high-resolution laser-based techniques

Two modern laser-based techniques were synchronously applied to study the dynamics of the trans-resveratrol activity in Botrytis cinerea-infected grapes. Direct analysis of trans-resveratrol in both infected and noninfected grapes (Vitis vinifera, Aledo variety) was performed by using an analytical technique incorporating laser desorption coupled with laser resonant ionization and time-of-flight mass spectrometry. On the other hand, one of the most sensitive on-line methods for trace gas detection, laser photoacoustic spectroscopy, was used to investigate the involvement of the plant hormone ethylene (C(2)H(4)) in the B. cinerea grapes interaction and its temporal relationship with the trans-resveratrol content upon infection. The trans-resveratrol content and the ethylene released by noninfected grapes showed an opposite behavior. In this case, a high trans-resveratrol content corresponds to a low ethylene emission. For the B. cinerea-infected grapes, ethylene emission rises up after 48 h when the analogous content of trans-resveratrol started to decrease irreversibly. Moreover, the activity of trans-resveratrol as natural pesticide has been investigated by exogenous application on grapes. A short submerge (5 s) of the grapes in 1.6 x 10(-4) M solution of trans-resveratrol delays the increase of C(2)H(4) emission with about 48 h and produces a decrease of the C(2)H(4) concentration and its emission rate. The treatment has positive effects on fruit conservation during storage; it doubled the normal shelf-life of grapes at room temperature, maintaining their post-harvest quality within 10 d.

Improving postharvest resistance in fruits by external application of trans-resveratrol

As it is well-known, one of the main problems of modern agriculture is the postharvest fruit losses due to pathogen's attack and natural senescence during storage. Well established solutions to improve this situation, such as, for example, storage under controlled conditions and the use of synthetic pesticides, are not free of problems due to human health risks and environmental effects caused by chemical pesticides. A new strategy to solve these problems consists of developing methods to improve the natural plant resistance by using, upon their identification, the plant's own defense molecules, in other words, applying methods based on the plant's own natural processes of pest suppression to control spoilage. This requires the identification of components of the natural defense response in plants, which, in turn, demands highly sensitive, fast, and versatile analytical methods especially for trace, nonvolatile, compounds. In this work a laser-based technique has been applied for screening the postharvest elicitation of resveratrol by Botrytis cinerea in grapes. Besides antifungal character, resveratrol is known to present important antioxidant properties, which could also have positive effects on fruit conservation during storage. Consequently, several experiments were carried out in which exogenous application of resveratrol to several fruits maintained their postharvest quality. The quality of both resveratrol-treated and untreated fruits has been studied by the assessment of the biochemical composition and sensory analysis. Indeed, the present work demonstrates that the external application of resveratrol does not alter the sensorial and biochemical properties of the fruit.

Sulfinyl-mediated chirality transfer in diastereoselective Claisen rearrangements

[reaction: see text] The highly selective Claisen rearrangements of substrates bearing a sulfinyl moiety at C-5 allow for creation of up to two asymmetric centers and preserve a useful vinyl sulfoxide.

Analysis of trans-resveratrol by laser desorption coupled with resonant ionization spectrometry. Application to trans-resveratrol content in vine leaves and grape skin

A method has been developed for nonvolatile compound analysis in fruits, namely, trans-resveratrol in grapes and vine leaves. This has been accomplished by the combination of laser desorption with resonance-enhanced multiphoton ionization coupled to time-of-flight mass spectrometry detection. After the optimization of the experimental conditions and the finding of the resonant wave-length of the substance, the full validation of the technique (i.e., linearity, repeatability, reproducibility, accuracy, detection limit, and quantification limit) was carried out with satisfactory results. Essential features of the method are as follows: (1) an enhanced desorption yield due to the mixing of the analyte with metal powder and (2) a high resolution and sensitivity and a low detection limit due to laser resonant ionization and mass spectrometric detection. Application to the analysis of trans-resveratrol in vine leaves and grape skin demonstrated the capabilities of the analytical method reaching detection limits of only few ppb.

Intrinsic resistance of Mycobacterium smegmatis to fluoroquinolones may be influenced by new pentapeptide protein MfpA

The fluoroquinolones (FQ) are used in the treatment of Mycobacterium tuberculosis, but the development of resistance could limit their effectiveness. FQ resistance (FQ(R)) is a multistep process involving alterations in the type II topoisomerases and perhaps in the regulation of efflux pumps, but several of the steps remain unidentified. Recombinant plasmid pGADIV was selected from a genomic library of wild-type (WT), FQ-sensitive M. smegmatis by its ability to confer low-level resistance to sparfloxacin (SPX). In WT M. smegmatis, pGADIV increased the MICs of ciprofloxacin (CIP) by fourfold and of SPX by eightfold, and in M. bovis BCG it increased the MICs of both CIP and SPX by fourfold. It had no effect on the accumulation of (14)C-labeled CIP or SPX. The open reading frame responsible for the increase in FQ(R), mfpA, encodes a putative protein belonging to the family of pentapeptides, in which almost every fifth amino acid is either leucine or phenylalanine. Very similar proteins are also present in M. tuberculosis and M. avium. The MICs of CIP and SPX were lower for an M. smegmatis mutant strain lacking an intact mfpA gene than for the WT strain, suggesting that, by some unknown mechanism, the gene product plays a role in determining the innate level of FQ(R) in M. smegmatis.

The evaluation of yeast derivatives as adjuvants for the immune response to the Bm86 antigen in cattle

BACKGROUND

The Gavac vaccine against the cattle tick Boophilus microplus has proven its efficacy in a large number of controlled and field experiments. However, this vaccine could be further improved by searching for new alternative adjuvants that would induce a stronger long-lasting immune response. We conducted several experiments to assay the adjuvant effect of fractions of the recombinant yeast Pichia pastoris in mouse and cattle models. In previous experiments, the combination of the yeast membrane with saponin was the most effective formulation in stimulating the humoral immune response in mice, eliciting a response higher than Montanide 888. The response was predominantly of the IgG1 isotype. Here, we evaluated the response in cattle and compared the results with that obtained in mice.

RESULTS

Bm86 on the membrane of P. pastoris plus saponin produced high antibody titers in cattle, though the protection level against tick infestations was lower when compared to Gavac, probably due to a decrease in the IgG1/IgG2 ratio. The predictive value of the mouse model was studied through correlation analysis between the isotype levels in mice and the efficacy of formulations in cattle. Good correlation was established between the level of antibodies in mice and cattle, and between the amount of anti -Bm86 IgG1 in mice and the degree of protection in cattle.

CONCLUSION

Mouse model have the potential to predict immunogenicity and efficacy of formulations in cattle. These results also support the use of the yeast expression system for recombinant vaccine formulations, enabling the prediction of more cost--effective formulations.

Sulfoxide-controlled S(N)2' displacements between cyanocuprates and epoxy vinyl sulfoxides

Two short and convergent routes have been devised for the preparation of enantiomerically pure acyclic epoxy vinyl sulfoxides. These substrates undergo highly regio- and stereoselective S(N)2' displacements with lithium cyanocuprates to give alpha'-alkylated, gamma-oxygenated Z alpha,beta-unsaturated sulfoxides in moderate to good yields and with good to excellent diastereoselectivities. The absolute configuration of the newly formed carbon-carbon bond is primarily controlled by the chiral sulfur atom, which in a nonreinforcing situation can override the intrinsic anti tendency of the vinyl oxirane moiety and forces the cuprate to undergo syn addition. The hydroxy vinyl sulfoxide functionality of the resulting adducts should allow for subsequent asymmetric transformations thus enhancing the synthetic usefulness of this methodology.

Chronic calf pain in athletes due to sural nerve entrapment. A report of 18 cases

We retrospectively analyzed the charts of 13 athletes (18 limbs) who had sural nerve entrapment localized in the passage of the nerve through the superficial sural aponeurosis. There were 11 men and 2 women (average age, 43 years; range, 31 to 59). All patients reported chronic calf pain that was exacerbated during physical exertion. Delay to diagnosis averaged 9 months (range, 5 to 24). Tenderness in the calf was identified along the course of the sural nerve in all cases. In 10 patients (15 limbs) electrodiagnostic testing before surgery was positive. After failure of nonoperative treatment, surgery was conducted under local anesthesia. Neurolysis was performed by incising the superficial sural aponeurosis and the fibrous band in it through which the nerve passes. The results of the operation were evaluated in terms of residual symptoms, ability to return to the former sport, and degree of patient satisfaction. A final follow-up examination was performed an average of 14 months (range, 6 to 30) after the operation. The final result was excellent in 9 limbs (2 bilateral), good in 8 limbs (2 bilateral), and fair in 1 case. The differential diagnosis of sural nerve entrapment in athletes is discussed. Increase in sural muscle mass or development of local fibrous scar tissue compromised the sural nerve in its course through the unyielding and inextensible superficial sural aponeurosis.

Antiviral and antiluteolytic activity of recombinant bovine IFN-omega1 obtained from Pichia pastoris

The gene coding for bovine interferon-omega1 (BoIFN-omega1) was recently cloned and expressed at high levels in the yeast Pichia pastoris. The recombinant BoIFN-omega1 protein shows antiviral activity in different cell lines and has an antiluteolytic effect in cyclic ewes. In this article, we describe a method for purification of BoIFN-omega1 expressed in the methylotrophic yeast P. pastoris and characterization of its activity in vivo. The recombinant protein secreted to the culture medium had low activity because of self-aggregation. BoIFN-omega1 was solubilized using urea and desalting and finally purified by ion exchange chromatography on Q-Sepharose Fast Flow. The yield of purified product was approximately 300 mg/L of fermentation culture, with a specific antiviral activity of 10(8) IU/mg. Its purity was at least 80%. The biologic characterization of purified BoIFN-omega1 was determined by induction of an antiviral state on ewes challenged with 100 lethal doses (LD) of Aujeszky virus and by the extension of the corpus luteum life span and interestrous interval in cyclic cows. Ewes treated with 2 x 106 IU/kg BoIFN-omega1 were protected from Aujeszky virus infection. In cows receiving an intrauterine infusion of 1 mg BoIFN-omega1, equally distributed between the two uterine horns, twice daily from day 14 to day 22 of the experimental estrous cycle, the lifespan of the corpus luteum (25 vs. 19 days) and the interestrous intervals (26 vs. 21 days) were extended when compared with a control group (p < 0.05). We show that recombinant BoIFN-omega1 purified from P. pastoris has high antiviral activity and is an effective antiluteolytic agent in cattle.

Control of ticks resistant to immunization with Bm86 in cattle vaccinated with the recombinant antigen Bm95 isolated from the cattle tick, Boophilus microplus

The recombinant Bm86-containing vaccine Gavac(TM) against the cattle tick Boophilus microplus has proved its efficacy in a number of experiments, especially when combined with acaricides in an integrated manner. However, tick isolates such as the Argentinean strain A, show low susceptibility to this vaccine. In this paper we report on the isolation of the Bm95 gene from the B. microplus strain A, which was cloned and expressed in the yeast Pichia pastoris producing a glycosylated and particulated recombinant protein. This new antigen was effective against different tick strains in a pen trial, including the B. microplus strain A, resistant to vaccination with Bm86. A Bm95-based vaccine was used to protect cattle against tick infestations under production conditions, lowering the number of ticks on vaccinated animals and, therefore, reducing the frequency of acaricide treatments. The Bm95 antigen from strain A was able to protect against infestations with Bm86-sensitive and Bm86-resistant tick strains, thus suggesting that Bm95 could be a more universal antigen to protect cattle against infestations by B. microplus strains from different geographical areas.

Application of the critical molar concentration concept to heat-mediated antigen retrieval in immunohistochemistry

Previously we have applied Scott's critical molar concentration concept to show that divalent cations, especially Mg2+ may be used to measure the affinity of a known monoclonal antibody for its antigen. In this paper we report the application of this same procedure to a study of a series of antigens (three globular proteins and three intermediate filaments). The concept was applied to samples without any previous treatment or after the application of heat-mediated antigen retrieval (using a pressure cooker). Our findings suggest that heat-mediated antigen retrieval sets free protein side-chain(s) that have been masked by formaldehyde fixation. This is reflected in a higher affinity of the antibody for the antigen in question.

Planar Bragg gratings made by excimer-laser modification of ion-exchanged waveguides

The refractive indices of planar silver-ion-exchanged waveguides have been modified by UV excimer laser irradiation (lambda=193 nm) . The effective index changes of the fundamental modes of the waveguides after exposition are as large as 2x10(-2) . The procedure permits the fabrication of integrated optical components in a direct way, with neither the use of standard lithography nor previous sensitizing of the substrate. Optical characterization of the irradiated samples is presented. By the use of appropriate masks, we have fabricated planar Bragg gratings.

Vaccination against ticks (Boophilus spp.): the experience with the Bm86-based vaccine Gavac

The control of tick infestations and the transmission of tick-borne diseases remain a challenge for the cattle industry in tropical and subtropical areas of the world. Traditional control methods have been only partially successful and the parasites continue to result in significant losses for the cattle industry. Recently, vaccines containing the recombinant B. microplus gut antigen Bm86 have been developed. Our vaccine formulation (Gavac, Heber Biotec S.A., Havana, Cuba) has been registered and is commercially available in Cuba, Colombia, Dominican Republic, Brazil and Mexico. In controlled pen trials, Gavac has been effective for the control of artificial infestations of B. annulatus, B. decoloratus and chemical-sensitive and resistant B. microplus strains from Australia, Africa, America and Iran. In controlled field trials in Cuba, Brazil, Argentina and Mexico, Gavac has shown a 55-100% efficacy in the control of B. microplus infestations in grazing cattle 12-36 weeks after the first vaccination. Field trials under production conditions have been conducted in Cuba, Colombia, Brazil and Mexico in pure and cross-bred cattle herds. The application of Gavac has increased the time between acaricide treatments by an average of 32 /-21 days (P = 0.0005) resulting in important savings for the cattle industry. In Cuba, a cost-effectiveness analysis was conducted in more than 260000 animals. The cost-effectiveness analysis showed a 60% reduction in the number of acaricide treatments, together with the control of tick infestations and transmission of babesiosis, which resulted in savings of 23.4 dollars animal(-1) year (-1). These results clearly demonstrate the advantage of vaccination and support the application of Gavac for the control of Boophilus spp. infestations.

Integrated control of acaricide-resistant Boophilus microplus populations on grazing cattle in Mexico using vaccination with Gavac and amidine treatments

Throughout most of the twentieth century, tick infestations on cattle have been controlled with chemical acaricides, typically administered by dipping or spraying. This approach can cause environmental and residue problems and has created a high incidence of acaricide resistance within tick populations in the field. Recently we developed a vaccine against Boophilus microplus employing a recombinant Bm86 antigen preparation (Gavac), (Heber Biotec S.A., Havana, Cuba) which has been shown to induce a protective response in vaccinated animals. Here we show for the first time under field conditions a near 100% control of B. microplus populations resistant to pyrethroids and organophosphates, by an integrated system employing vaccination with Gavac and amidine treatments. This method effectively controls tick infestations while reducing the number of chemical acaricide treatments and consequently the rise of B. microplus populations resistant to chemical acaricides.

Reproductive and safety assessment of vaccination with Gavac against the cattle tick (Boophilus microplus)

Recent developments in cattle tick control have incorporated the use of recombinant Bm86 vaccines against this ectoparasite. The vaccine developed by our group (Gavac) contains an antigen expressed in Pichia pastoris, and has been successfully employed for the control of tick infestations and transmission of tick-borne diseases. Here, we examined the safety and effect of the Gavac vaccine on reproductive parameters in cattle. Toxicity tests in mice and guinea pigs demonstrated the safety of Gavac. To study the adverse effects of vaccination on reproduction, a field trial involving 9,500 animals in Cuba was conducted. The cattle at 3 farms were vaccinated while those on a fourth farm were left unvaccinated and served as the control. Following vaccination, the control of tick infestation and the transmission of babesiosis were used to demonstrate the efficacy of the vaccine. No adverse effects were observed in any of the reproductive parameters studied when comparing the data before and after vaccination with Gavac and between the vaccinated farms and the control farm. These results demonstrate that under the conditions of our study vaccination with Gavac is safe for use on cattle.

Fibrosing mediastinitis: CT and MR findings

The aim of this study is to present the computed tomography (CT) and magnetic resonance (MR) findings in three cases of fibrosing mediastinitis, probably secondary to tuberculosis. Two patients had diffuse involvement of the mediastinum and one patient presented with a posterior mediastinal mass. On CT, the patients with diffuse involvement showed infiltrating soft-tissue masses with multiple foci of dense calcifications. One of these lesions enhanced mildly with contrast and one did not enhance. On MR examination, diffuse masses were of heterogeneous, intermediate and low signal on T1-weighted images (n = 2) and were of homogeneous low signal (n = 1) or heterogeneous (n = 1) signal intensity on T2-weighted images. After administration of Gd-DTPA, these mediastinal masses showed heterogeneous enhancement. The posterior mediastinal mass showed homogeneous pronounced enhancement on CT and was homogeneous with intermediate T1 signal intensity and hypointense T2 signal intensity. The CT findings of an infiltrative or well-defined mediastinal mass with scattered calcifications should suggest the diagnosis of fibrosing mediastinitis in the appropriate clinical setting. Although the appearance of calcification on MR are not specific, this technique provides further information than CT especially in those cases in which the lesions appear noncalcified, because MR imaging revealed areas of low signal intensity characteristic of fibrous tissue.