[Guillain-Barre syndrome in times of arbovirosis. Reply]. / Sindrome de Guillain-Barre en tiempos de arbovirosis. Replica.

TITLE: Sindrome de Guillain-Barre en tiempos de arbovirosis. Replica.

[The most frequent causative agents of Guillain-Barre syndrome in a Mexican general hospital]. / Agentes causales mas frecuentes del sindrome de Guillain-Barre en un hospital de Veracruz, Mexico.

INTRODUCTION: After Zika virus outbreak and the increase in the incidence of Guillain-Barre syndrome (GBS), the causal relationship has been studied, however a full etiological correlation has not been found. PATIENTS AND METHODS: From January 1 to December 31, 2017, patients with GBS were included. In addition to the basic serologies, enterovirus, herpes, Campylobacter, hepatitis B and C, TORCH, HIV, Brucella and Salmonella were requested. RESULTS: Cohort of seven male patients. Five patients analyzed cerebrospinal fluid reporting normal; all of them underwent brain scan, reporting normal. Neuroconduction was performed, resulting in acute inflammatory demyelinating polyneuropathy in four cases and acute motor axonal neuropathy in one case. All received intravenous immunoglobulins, five cases had a good prognosis and two deaths. No positive cases were reported to Zika virus. A positive case was reported to dengue and another to chikungunya. Five positive cases were reported to Campylobacter. One case positive to enterovirus. Dengue + Campylobacter coinfections were reported in one case and chikungunya + Campylobacter in another case. CONCLUSIONS: The present cohort shows that it was not possible to establish a causal relationship between GBS and Zika virus, but other viral and bacterial causal agents were identified, such as dengue, chikungunya and enterovirus, with the identification of Campylobacter cases even more remarkable.

TITLE: Agentes causales mas frecuentes del sindrome de Guillain-Barre en un hospital de Veracruz, Mexico.Introduccion. Con posterioridad a la oleada del virus del Zika y el incremento en la incidencia de sindrome de Guillain-Barre (SGB), se ha estudiado la relacion causal, pero no se ha encontrado una plena correlacion etiologica. Pacientes y metodos. Del 1 de enero al 31 de diciembre de 2017, se incluyeron pacientes con SGB. Ademas de las serologias basicas, se solicitaron determinaciones de enterovirus, virus del herpes, Campylobacter, hepatitis B y C, TORCH, virus de la inmunodeficiencia humana, Brucella y Salmonella. Resultados. Cohorte de siete pacientes de sexo masculino. A cinco pacientes se les analizo el liquido cefalorraquideo, que era normal. A todos se les realizo una tomografia encefalica, tambien normal, y se realizo neuroconduccion, que mostro polineuropatia inflamatoria desmielinizante aguda en cuatro casos y neuropatia motora axonal aguda en uno. Todos recibieron inmunoglobulinas intravenosas; tuvieron buen pronostico cinco casos y hubo dos defunciones. No se informo de casos positivos al virus del Zika. Hubo un caso positivo al dengue, uno al chikungunya, cinco a Campylobacter y uno a enterovirus. Se informo de coinfecciones de dengue + Campylobacter en un caso y de chikungunya + Campylobacter en otro. Conclusiones. La presente cohorte demuestra que no fue posible establecer una relacion causal entre el SGB y el virus del Zika, pero se identificaron otros agentes causales viricos y bacterianos, como dengue, chikungunya y enterovirus, y fue aun mas destacable la identificacion de los casos de Campylobacter.

The Reaction between Sodium Hydroxide and Atomic Hydrogen in Atmospheric and Flame Chemistry.

We report the first direct kinetic study of the gas-phase reaction NaOH + H → Na + H2O, which is central to the chemistry of sodium in the upper atmosphere and in flames. The reaction was studied in a fast flow tube, where NaOH was observed by multiphoton ionization and time-of-flight mass spectrometry, yielding k(NaOH + H, 230-298 K) = (3.8 ± 0.8) × 10-11 cm3 molecule -1 s-1 (at 2σ confidence level), showing no significant temperature dependence over the indicated temperature range and essentially in agreement with previous estimates of the rate constant in hydrogen-rich flames. We show, using theoretical trajectory calculations, that the unexpectedly slow, yet T-independent, rate coefficient for NaOH + H is explained by severe constraints in the angle of attack that H can make on NaOH to produce H2O. This reaction is also central to explaining Na-catalyzed flame inhibition, which has been proposed to occur via the sequence Na + OH (+ M) → NaOH followed by NaOH + H → Na + H2O, thereby effectively recombinating H and OH to H2O. RRKM calculations for the recombination of Na and OH yield k(Na + OH + N2, 300-2400 K) = 2.7 × 10-29 (300/T)1.2 cm6 molecule-2 s-1, in agreement with a previous flash photolysis measurement at 653 K and Na-seeded flame studies in the 1800-2200 K range. These results therefore provide strong evidence to support the mechanism of flame inhibition by Na.

Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae).

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus worldwide due to its ability to transmit the bacteria associated with huanglongbing. Vision, behavior, and performance of insect pests can be manipulated by using ultraviolet (UV)-blocking materials. Thus, the aim of our study was to evaluate how UV-blocking plastic films may affect the take-off and host plant finding ability of D. citri. To assess the effect of a UV-deficient environment on take-off, adult psyllids were released from a vial inside a screenhouse covered by a UV-blocking or standard (control) film and the number of insects remaining on each vial under each treatment was counted at different time intervals. Moreover, to assess the ability of D. citri to find citrus plants under a UV-deficient environment, two independent no-choice host plant finding assays with different plant arrangements were conducted. In each treatment, the number of psyllids per plant at different time intervals was counted. Both D. citri take-off and host plant finding ability was clearly disrupted under a UV-deficient environment. The number of psyllids remaining in the vials was significantly higher under UV-blocking than standard film in all periods recorded. Furthermore, psyllids were present in significantly higher number on citrus plants under standard film than under UV-blocking film in all of the periods assessed and experiments conducted. Our results showed that UV-blocking materials could become a valuable strategy for integrated management of D. citri and huanglongbing in citrus grown in enclosed environments.

Polifenóis totais e flavonoides em amostras de chá verde (Camellia sinensis L. ) de diferentes marcas comercializadas na cidade de Salvador-BA / Contents of phenolics and flavonoids in green tea (Camellia sinensis) from samples of different brands available for sale in Salvador-Ba

RESUMO Camellia sinensis é amplamente conhecida por seus efeitos benéficos à saúde humana. Dentre as diversas formas de processamento desta erva, o chá verde e chá preto são os mais populares. Neste trabalho objetivou-se avaliar os teores de fenólicos totais e flavonoides em amostras de 25 diferentes marcas disponíveis à venda em farmácias e supermercados de Salvador-Ba. Os resultados obtidos apresentaram diferenças significativas na concentração dos compostos fenólicos entre as marcas de chá verde estudadas. No estudo também ficou comprovado que, no preparo do chá verde, as amostras obtidas por infusão aquosa com agitação mecânica apresentaram maiores teores de polifenóis e flavonoides em relação àquelas que não foram submetidas à agitação.

ABSTRACT Camellia sinensis is widely known for its beneficial effects to human health. Among the various forms of processing this herb, the green and the black tea are the most popular ones. The objective of this work was to evaluate the contents of total polyphenol and flavonoids in samples of 25 different brands available for sale in pharmacies and supermarkets of Salvador-Ba. The results showed great variation in the concentration of phenolic compounds among the brands of green tea which were tested. In the study it was also proven that in the green tea preparation the samples obtained by mechanical agitation with aqueous infusion showed higher levels of phenolics and flavonoids contents than those which were not subjected to stirring.

The reactive collision mechanism evinced: stereodynamical control of the elementary Br + H2 → H + HBr reaction.

From a kinetics standpoint, reactive molecular collisions are the building blocks of the mechanisms of chemical reactions. In contrast, a dynamics standpoint reveals molecular collisions to have their own internal mechanisms, which are not mere theoretical abstractions: through suitable preparation of the reactants internal and stereochemical states, features of the mechanisms of a reactive molecular collision can be made evident and used as "handles" to control the reaction outcome. Using time-independent quantum dynamical calculations, we demonstrate this for the Br + H2(v = 0-1, j = 2) → H + HBr reaction in the 1.0-1.6 eV range of total energies. Despite its pronounced effect on reactivity, which is in agreement with the predictions from Polanyi rules, reactant vibration is found to have little effect on the mechanism of this endoergic, late-barrier reaction. Analysis of the correlations between directional reaction properties shows that the collision stereochemistry strongly depends on the total energy, but not on how this energy is partitioned between reactant translation and vibration. The stereodynamical preferences implied by the collision mechanisms determine how and to what extent one can control the reaction. Regarding the overall reaction, the extent of control is found to be large near the reaction threshold but not when the total energy is high. Regarding state-to-state reactions, the effect of reactant stereochemistry on the product rotational state distribution is found to be nontrivial and energy dependent.

Rotational alignment effects in NO(X) + Ar inelastic collisions: a theoretical study.

Rotational angular momentum alignment effects in the rotational inelastic scattering of NO(X) with Ar have been investigated by means of close-coupled quantum mechanical, quasi-classical trajectory, and Monte Carlo hard shell scattering calculations. It has been shown that the hard shell nature of the interaction potential at a collision energy of Ecoll = 66 meV is primarily responsible for the rotational alignment of the NO(X) molecule after collision. By contrast, the alternating trend in the quantum mechanical parity resolved alignment parameters with change in rotational state Δj reflects differences in the differential cross sections for NO(X) parity conserving and changing collisions, rather than an underlying difference in the collision induced rotational alignment. This suggests that the rotational alignment and the differential cross sections are sensitive to rather different aspects of the scattering dynamics. The applicability of the kinematic apse model has also been tested and found to be in excellent agreement with exact quantum mechanical scattering theory provided the collision energy is in reasonable excess of the well depth of the NO(X)-Ar potential energy surface.

Aortic clamping in pancreas transplantation: is there any harm to the transplanted kidney graft?

INTRODUCTION: Some special situations may require aortic clamping during pancreas transplantation (PT). The most important problem is ischemic injury to a previous transplanted kidney. We sought to demonstrate experience with aortic clamping in PT without special kidney allograft protection measures and its impact on kidney function. METHODS: Retrospective study that analyzed 6 patients who underwent PT (5 pancreas after kidney and 1 simultaneous pancreas-kidney) with aortic clamping. In all cases, the pancreas graft was placed on the right with retrocolic portal-enteric drainage. Serum creatinine was evaluated pre- and posttransplantation. RESULTS: The average clamping time was 19 minutes. The mean serum creatinine was 1.1, 1.15, 0.95, and 1.0, respectively, at pre and postoperative days 1 and 7 and at hospital discharge. Patient, kidney, and pancreatic graft survivals were 100%, 100%, and 83%, respectively. CONCLUSION: The need for aortic clamping in selected cases of PT did not seem to affect the transplanted kidney, even without protective measures, provided that the ischemic time was short.

Three-vector correlation in statistical reactions: the role of the triatomic parity.

This article presents a methodology for the determination of the k-j-k' three-vector correlation assuming a statistical model for atom-diatom reactions; k and k' are the reagent-approach and product-recoil directions, respectively, and j is the rotational angular momentum of the reagent diatomic. Although the polarization of reagent angular momentum is in most cases negligible, conservation of the triatomic parity imposes a certain polarization for some combinations involving low reagent and product rotational states. Statistical and quantum-mechanical polarization-dependent differential cross sections were calculated for the barrierless D(+) + H(2)(v = 0,j) → HD(v' = 0,j') + H(+) reaction. The agreement between the two is in most cases excellent, confirming the statistical character of the reaction at low and moderate collision energies.

Orientation effects in Cl + H2 inelastic collisions: characterization of the mechanisms.

Based on quantum mechanical scattering (QM) calculations, we have analyzed the polarization of the product hydrogen molecule in Cl + H(2) (v = 0, j = 0) inelastic collisions. The spatial arrangements adopted by the rotational angular momentum and internuclear axis of the departing molecule have been characterized and used to prove that two distinct mechanisms, corresponding to different dynamical regimes, are responsible for the inelastic collisions. Such mechanisms, named as low-b and high-b, correlate with well defined ranges of impact parameter values, add in an essentially incoherent way, and can be clearly differentiated through the quantum mechanical polarization moment that measures the orientation of the products rotational angular momentum with respect to the scattering plane. Other directional effects turn out to fail when it comes to distinguishing the mechanisms. Quasiclassical trajectories (QCT) calculations have been used as a supplement to the purely quantum mechanical analysis. By combining QM and QCT results, which are in very good agreement, we have succeeded in obtaining a clear and meaningful picture of how the two types of collisions take place.

Liver transplantation in bearers of hepatitis B associated or not with delta hepatitis in the age of the new antiviral drugs: is hyperimmune globulin still necessary?

Hepatitis B (HBV) is a public health problem worldwide; one-third of the population has already been in contact with HBV, and 350 million people are chronic carriers of virus. The appearance of hyperimmune gamma globulin and antiviral drugs has allowed that group to undergone hepatic transplantation, achieving satisfactory results to prevent a relapse. But the use of hyperimmune gamma globulin has an extremely high cost, and combined therapies with new antiviral drugs seem to be a therapeutic alternative. We analyzed 21 patients with hepatitis B associated or not with Delta hepatitis over a mean follow-up period of 19.5 months, concluding that use of only nucleotide analogues has sufficient to achieve satisfactory results.

Simultaneous pancreas-kidney transplantation in a human immunodeficiency virus-positive recipient: a case report.

BACKGROUND: After the development of highly active antiretroviral therapy (HAART) for patients with human immunodeficiency virus (HIV), there has been increased interest in organ transplantation for this selected population. There is a lack of reports about pancreas transplant in HIV+ recipients. CASE REPORT: We report the case of a 43-year-old HIV+ man who presented with type 1 diabetes for 25 years and end-stage-renal disease. He underwent dialysis therapy for the prior 3 years. His CD4 count was 830 cells/mL and a negative viral load was achieved after 3 months of antiretroviral therapy. His nutritional status was favorable; no opportunistic infections had occurred. A simultaneous pancreas-kidney transplantation (SPKT) was performed from a 19-year-old deceased trauma victim. Pancreas implantation was enteric-portal drainage. No induction immunosuppression was used, but rather tacrolimus, sodium mycophenolate, and steroids. In the postoperative period, there was a delayed kidney graft function requiring hemodialysis for 14 days. On postoperative day 11, a kidney biopsy specimen showed mild rejection, which was successfully treated with steroids. The patient was discharged after 22 days; he was normoglycemic and insulin-independent with a serum creatinine value of 1.9 mg/dL. Currently, his outcome has been uneventful, without a readmission or opportunistic infections. After 5 months postoperation, the viral load is negative and the CD4 count is 460 cells/mL. The current serum creatinine level is 1.1 mg/dL; no insulin has been required. COMMENT: HIV has been considered to be an absolute contraindication to organ transplantation, because of the infection risk due to severe immunosuppression, to interactions between antiretroviral and immunosuppressive drugs, and to reluctance to offer an organ to a terminal patient. However, transplants in HIV+ patients have shown good results, when a patient has an acceptable CD4 level, a low viral load, and minimal antiretroviral therapy.

The collisional depolarization of (2S+1)Sigma radicals by closed shell atoms: Theory and application to OH(A (2)Sigma(+))+Ar.

Classical and quantum mechanical expressions for the j-j(') vector correlation (also referred to as the rotational tilt) are presented for the situation in which the initial and final relative velocity directions are unresolved. The quantum mechanical expressions are compared with previous descriptions in the literature. It is shown that in the case of (2S+1)Sigma radicals in collision with closed shell species, a tensor opacity formalism can be employed in quasiclassical trajectory calculations to provide classical estimates of both open shell spin-rotation state and nuclear hyperfine state changing (or conserving) cross sections. Polarization parameters are also obtained from the same formalism. The method is applied to calculations on the OH(A (2)Sigma(+))-Ar system using a recently developed potential energy surface. The results of both the closed and open shell quasiclassical trajectory calculations are found to compare favorably with those from close-coupled closed and open shell quantum mechanical scattering calculations. The accompanying paper provides an experimental test of these calculations and of the potential energy surface they employ.

Constraints at the transition state of the D + H2 reaction: quantum bottlenecks vs. stereodynamics.

This article presents a quasiclassical trajectory method for the calculation of cumulative reaction probabilities by sampling of the helicity quantum number of the reagents (k). The method is applied to the D + H(2) reaction at various total angular momentum (J) values, and the helicity-resolved quasiclassical cumulative reaction probabilities are compared to their quantum mechanical counterparts. The agreement between the two sets of results is fairly good. In particular, k-dependent, J-independent reaction thresholds found with quantum methods are reproduced by the quasiclassical calculations. The shift of these thresholds with increasing k, which has been previously attributed to the quantum bottleneck states taking part in the reaction, is revisited and discussed also in terms of the reaction stereodynamics.

Mechanism and control of the F+H2 reaction at low and ultralow collision energies.

This article uses theoretical methods to study the dependence on stereodynamical factors of the mechanism and reactivity of the F+H2 reaction at low and ultralow collision energies. The impact of polarization of the H2 reactant on total and state-to-state integral and differential cross sections is analyzed. This leads to detailed pictures of the reaction mechanism in the cold and ultracold regimes, accounting, in particular, for distinctions associated with the various product states and scattering angles. The extent to which selection of reactant polarization allows for external control of the reactivity and reaction mechanism is assessed. This reveals that even the simplest of reactant polarization schemes allows for fine, product state-selective control of differential and (for reactions involving more than a single, zero orbital angular momentum partial wave) integral cross sections.

Analysis of the H + D2 reaction mechanism through consideration of the intrinsic reactant polarisation.

The effect of reactant polarisation on the dynamics of the title reaction at collision energies up to 1.6 eV is analysed in depth. The analysis takes advantage of two novel theoretical concepts: intrinsic reaction properties and stereodynamical portraits. Exact quantum methods are used to determine the polarisation moments that quantify the intrinsic reactant polarisation at various levels of detail, including or not product state and/or scattering angle resolution. The data is then examined with the aid of stereodynamical portraits, which facilitate the rationalisation of the stereochemical effects that are relevant for the reaction dynamics. This allows for detailed characterisations of the so-called direct and delayed reaction mechanisms.

No induction versus anti-IL2R induction therapy in simultaneous kidney pancreas transplantation: a comparative analysis.

UNLABELLED: The optimal immunosuppressive regimen for simultaneous kidney pancreas transplantation (SKPT) is still not established. We conducted a study to compare the safety and efficacy of no induction versus anti-IL-2 receptor induction protocols in SKPT recipients receiving the same maintenance regimen. METHODS: Sixty-three SKPT recipients were divided into two groups: no induction group (n = 42) and anti-IL-2 receptor induction group (n = 21). All patients were maintained on tacrolimus, mycophenolate mofetil, and prednisone. Primary endpoints were 1-year acute rejection incidence and patient and graft survivals. RESULTS: Demographic characteristics were similar between the groups. Acute rejection incidence at 1 year was equal in both groups (28.6%). Kidney and pancreas allograft survival in the no induction group were 78.6% and 76.2%, and in the anti-IL-2R induction group, 81% and 71.4%, respectively (P = NS). Patient survival was also similar: 83.3% in the no induction versus 85.7% in the anti-IL-2R induction group. Deaths due to sepsis were higher in the anti-IL-2R induction group, albeit not significantly. CONCLUSION: The use of a no-induction protocol in SKPT is safe and effective immunosuppression that also reduces transplantation costs.

Metabolic engineering of a xylose-isomerase-expressing Saccharomyces cerevisiae strain for rapid anaerobic xylose fermentation.

After an extensive selection procedure, Saccharomyces cerevisiae strains that express the xylose isomerase gene from the fungus Piromyces sp. E2 can grow anaerobically on xylose with a mu(max) of 0.03 h(-1). In order to investigate whether reactions downstream of the isomerase control the rate of xylose consumption, we overexpressed structural genes for all enzymes involved in the conversion of xylulose to glycolytic intermediates, in a xylose-isomerase-expressing S. cerevisiae strain. The overexpressed enzymes were xylulokinase (EC 2.7.1.17), ribulose 5-phosphate isomerase (EC 5.3.1.6), ribulose 5-phosphate epimerase (EC 5.3.1.1), transketolase (EC 2.2.1.1) and transaldolase (EC 2.2.1.2). In addition, the GRE3 gene encoding aldose reductase was deleted to further minimise xylitol production. Surprisingly the resulting strain grew anaerobically on xylose in synthetic media with a mu(max) as high as 0.09 h(-1) without any non-defined mutagenesis or selection. During growth on xylose, xylulose formation was absent and xylitol production was negligible. The specific xylose consumption rate in anaerobic xylose cultures was 1.1 g xylose (g biomass)(-1) h(-1). Mixtures of glucose and xylose were sequentially but completely consumed by anaerobic batch cultures, with glucose as the preferred substrate.

Diabetes mellitus: new therapeutic approaches to treat an old disease

Diabetes mellitus is a widespread disease whose frequency increases constantly and is expected to reach alarming levels by the year 2025. Introduction of insulin therapy represented a major breakthrough; however, a very strict regimen is required to maintain blood glucose levels within the normal range and to prevent or postpone chronic complications associated with this disease. Frequent hyper- and hypoglycemia seriously affect the quality of life of these patients. Reversion of this situation can only be achieved through whole organ (pancreas) transplant or pancreatic islet transplant, the former being a high-risk surgical procedure, while the latter is a much simpler and may be accomplished in only 20-40 min. The advantages and perspectives of islet cell transplantation will be discussed, in the light of tissue engineering and gene therapy. Ongoing research carried out in our laboratory, aimed at developing clinical cell and molecular therapy protocols for diabetes will also be focused