Estructura y composición arbórea en un gradiente altitudinal del Área Natural Protegida Metzabok, Chiapas, México / Tree structure and composition in an altitude gradient of the Metzabok Protected Natural Area, Chiapas, Mexico

Introducción: Las selvas albergan más de la mitad de las especies del planeta, a pesar de la biodiversidad que poseen son los ambientes más amenazados, principalmente por actividades antrópicas, y su complejidad con relación a la altitud alberga vacíos de información a pesar de los valores que representa. Objetivo: Describir la estructura y diversidad de árboles en un gradiente altitudinal. Métodos: En cinco estratos altitudinales (EA) se establecieron 21 unidades de muestreo (UM) de 20 x 50 m: seis en el EA1, cinco en EA2, cuatro en EA3, tres en EA4 y 5. La estructura se caracterizó mediante las categorías diamétricas y de altura, y de los índices de valor de importancia (IVI) y forestal (IVF). La diversidad se analizó con los índices de Shannon-Wiener (H´) y Simpson (S), mientras la semejanza florística con el coeficiente de Sørensen (IS). Resultados: Se registraron 209 especies, ocho registradas en la Norma Oficial Mexicana-059-Secretaría de Medio Ambiente y Recursos Naturales-2010 (NOM-059-SEMARNAT-2019). Las especies con los mayores IVI e IVF fueron: Haematoxylum campechianum y Manilkara zapota en EA1; Rinorea guatemalensis y Pouteria reticulata en EA2; M. zapota y Brosimum alicastrum en EA3; Guatteria anomala y Pseudolmedia spuria en EA4; y Terminalia amazonia y Pouteria durlandii en EA5. En los cinco EA se identificaron tres rangos de altura y seis de diámetro, el mayor número de individuos se encontró en la primera categoria diamétrica. La diversidad de las especies fue menor a mayor altitud. En los EA 2 y 3 se presentó la mayor semejanza (IS = 58.7 %). Conclusión: La estructura y diversidad de las especies arbóreas, presentan mayores cambios en intervalos altitudinales más amplios, relacionados con la necesidad ambiental de cada especie.

Introduction: The forests are home to more than half of the planet's species, despite of their biodiversity, they are the ecosystems most threatened mainly by anthropic activities, but their complexity in relation to altitude has information gaps despite of the values it represents. Objective: Describe the structure and diversity of trees on an altitudinal gradient. Methods: In five altitudinal strata (EA) 21 sampling plots (UM) of 20 x 50 m were established: six in EA1, five in EA2, four in EA3, three in EA4 and 5. The structure was characterized by the categories diametric and height, and the importance value indexes (IVI) and forestry (IVF). Diversity was analyzed with the Shannon-Wiener (H´) and Simpson (S) indices, while the floristic similarity with the Sørensen coefficient (IS). Results: It was registered 209 tree species, eight are listed in the Official Mexican Standard-059-Secretariat of the Environment and Natural Resources-2010 (NOM-059-SEMARNAT-2019) as vulnerable species. The species with the highest IVI and IVF were Haematoxylum campechianum and Manilkara zapota in EA1; Rinorea guatemalensis and Pouteria reticulata in EA2; M. zapota and Brosimum alicastrum at EA3; Guatteria anomala and Pseudolmedia spuria in EA4; and Terminalia amazonia and Pouteria durlandii at EA5. In the five EAs, three ranges of height and six of diameter were identified, the largest number of individuals was found in the first diametric range. Species diversity was lower at higher altitudes. In EA 2 and 3 the greatest similarity was presented (IS= 58.7 %). Conclusion: The structure and diversity of the tree species present greater changes in wider altitude ranges, related to the environmental need of each species.

Hairy roots as a vaccine production and delivery system.

Prevention of infectious diseases by vaccination is often limited because of the lack of safe, effective, and accessible vaccines. Traditional vaccines are expensive and require special conditions for storage, distribution, and administration. Plants have potential for large-scale production of a variety of inexpensive and highly effective recombinant proteins for biomedical and pharmaceutical applications, including subunit vaccines. There are several approaches for the production of vaccine antigens in plants, including transient expression systems based on Agrobacterium delivery of binary vectors or plant viral vectors, stable transgenic plants, and plant cell or tissue cultures. Axenic plant cultures maintained under defined physical and chemical conditions appear to be an attractive production platform when target proteins need to be synthesized in a fully controlled environment. Hairy root cultures meet the criteria for such a system. Hairy root cultures, generated from edible plants and producing target antigens, provide a potential approach for the development of vaccines for oral delivery. With this approach, there are no protein extraction and purification costs and the active biomolecule is protected by the plant cell wall during passage through the upper gastrointestinal tract. This allows for gradual release of antigen at mucosal surfaces in the gut. Lyophilized hairy root cultures expressing vaccine antigens can be stored at ambient temperature for extended periods of time, which should facilitate storage and distribution, ultimately allowing for large populations to be vaccinated.

Rotación a metadona para el dolor por cáncer: estudio prospectivo / Switching to metadone for cancer pain: prospective study

El objetivo de este estudio fue evaluar los beneficios de la rotación de morfina a metadona oral en pacientes con poca respuesta analgésica o efectos adversos derivados de la morfina. Diecisiete pacientes con cáncer avanzado que recibían morfina por dolor no controlado o efectos adversos severos fueron rotados a metadona cada ocho o doce horas, según un esquema de rotación rápida utilizando diferentes dosis ratios. La intensidad del dolor y efectos adversos fueron evaluados diariamente y comparados antes y después del cambio. Se documentó la dosis de morfina prerrotación, la dosis media inicial de metadona, dosis al séptimo día así como la dosis media final. Antes de la rotación la dosis media equivalente de morfina oral fue 118.71 mg/día, luego de la misma la dosis media inicial de metadona fue de 17.94 mg/día, al séptimo día fue 27.06 mg/día y la dosis media final de metadona fue 34.12 mg/día. Los motivos de la rotación fueron: dolor no controlado, efectos adversos limitantes o la suma de ambos. Se encontraron mejorías significativas en la analgesia (p<0.05) así como alivio sintomático relevante en los efectos adversos. Se registraron efectos colaterales debidos a la utilización de metadona en ocho pacientes que revirtieron con el tratamiento sintomático. La metadona demostró ser una opción terapéutica válida para el grupo de pacientes estudiados. Se recomienda precaución en la rotación a metadona en pacientes tolerantes a altas dosis de opioides.

The aim of this study was to evidence the clinical benefits of switching from morphine to oral methadone in patients who experience poor analgesia or adverse effects from morphine. Seventeen advanced cancer patients receiving morphine but with uncontrolled pain or severe opioid adverse effects were switched to oral methadone administered every 8 or 12 hours according to a scheme of rapid switching using different dose ratios.Intensity of pain and adverse effects were assessed daily and compared before and after switching. Pre switching doses of morphine, initial, day 7 and final methadone doses were recorded. Before the switch, the median equivalent daily dose of morphine was 118.71 mg/day; after the switch the initial dose of methadone (median) was 17.94 mg/day, 27.06 mg/day at day 7 and the final dose of methadone (median) was 34.12 mg/day. The reasons for switching were: uncontrolled pain, adverse effects or both. Significant improvements in pain (p<0.05) and relevant changes in adverse effects were reported. Methadone - related side effects reported in 8 patients were relieved after treatment. In patients with cancer pain and/or adverse effects of oral methadone is a valid therapeutic option.Caution is recommended when switching from any opioid to methadone, in patients who are tolerant to high doses of opioids.

O objetivo deste estudo foi avaliar os benefícios da passagem de morfina a metadona oral em pacientes com pouca resposta analgésica o efeitos adversos derivados da morfina. Dezessete pacientes com câncer avançado que recebiam morfina por dor não controlada o efeitos adversos severos foram medicados com metadona cada 8 ou 12 horas, adotando um esquema de conversão rápida utilizando diferentes doses-ratios. A intensidade da dor e efeitos adversos foi avaliada diariamente e comparados antes e depois da troca. Foi documentado a doses de morfina pré-conversão, a doses media inicial de metadona, a dosagem ao dia 7, como também a doses media final. Antes da troca a doses media equivalente de morfina oral foi de 118.71 mg/dia, logo após as doses media inicial de metadona foi de 17.94 mg/dia, ao dia 7 foi de 27.06 mg/dia e a doses final de metadona foi 34.12 mg/dia. O motivo da passagem a metadona foi: dor não controlada, efeitos adversos limitantes o a soma deles. Foram encontradas melhorias significativas na analgesia (p<0.05) alem do alivio relevante dos efeitos adversos. Se registraram efeitos colaterais pela utilização da metadona em 8 pacientes que melhoraram com o tratamento sintomático. A metadona demonstrou ser uma opção terapêutica valida para o grupo de pacientes estudados. Recomendamos cuidados na passagem a metadona em pacientes tolerantes a altas doses de opioides.

Plant-expressed HA as a seasonal influenza vaccine candidate.

Influenza is a globally important respiratory pathogen that causes a high degree of morbidity and mortality annually. Although current vaccines are effective against virus infection, new strategies need to be developed to satisfy the global demand for an influenza vaccine. To address this point, we have engineered and produced the full-length hemagglutinin (HA) protein from the A/Wyoming/03/03 (H3N2) strain of influenza in plants. The antigenicity of this plant-produced HA was confirmed by ELISA and single-radial immunodiffusion (SRID) assays. Immunization of mice with plant-produced HA resulted in HA-specific humoral (IgG1, IgG2a and IgG2b) and cellular (IFNgamma and IL-5) immune responses. In addition, significant serum hemagglutination inhibition (HI) and virus neutralizing (VN) antibody titers were obtained with an antigen dose as low as 5mug. These results demonstrate that plant-produced HA protein is antigenic and can induce immune responses in mice that correlate with protection.

A plant-produced influenza subunit vaccine protects ferrets against virus challenge.

BACKGROUND: Influenza A viruses are of major concern for public health, causing worldwide epidemics associated with high morbidity and mortality. Vaccines are critical for protection against influenza, but given the recent emergence of new strains with pandemic potential, and some limitations of the current production systems, there is a need for new approaches for vaccine development. OBJECTIVE: To demonstrate the immunogenicity and protective efficacy of plant-produced influenza antigens. Method We engineered, using influenza A/Wyoming/3/03 (H3N2) as a model virus, the stem and globular domains of hemagglutinin (HA) produced in plants as fusions to a carrier protein and used purified antigens with and without adjuvant for ferret immunization. RESULTS: These plant-produced antigens were highly immunogenic and conferred complete protection against infection in the ferret challenge model. The addition of plant-produced neuraminidase was shown to enhance the immune response in ferrets. CONCLUSIONS: Plants can be used as a production vehicle for vaccine development against influenza. Domains of HA can generate protective immune responses in ferrets.

Immunogenicity of a subunit vaccine against Bacillus anthracis.

The current approved vaccine against anthrax is based on protective antigen (PA) of Bacillus anthracis, requires six injections over an 18-month period and has a known history of side effects. Therefore, there is significant effort towards developing an improved vaccine against B. anthracis. Here we separately engineered and expressed domain 4 of PA (PAD4) and domain 1 of lethal factor (LFD1) as fusions to lichenase (LicKM), a thermostable enzyme from Clostridium thermocellum, and transiently expressed these fusions in Nicotiana benthamiana. Plant-produced antigens were combined and immunogenicity was evaluated in mice. All animals that received the experimental vaccine developed high antibody titers that were predominantly IgG1 and were able to neutralize the effects of LeTx in vitro.

The polysaccharide antibody response after Streptococcus pneumoniae vaccination is differentially enhanced or suppressed by 3,4-dichloropropionanilide and 2,4-dichlorophenoxyacetic acid.

Propanil (3,4-dichloropropionanilide) and 2,4-D (2,4-dichlorophenoxyacetic acid) are commonly used herbicides that have toxic effects on the immune system. The present study determined the effect of exposure to these chemicals on the immune response to a bacterial vaccine. The antibody responses to the T-independent type 2 antigen, phosphorylcholine (PC) and the T-dependent antigen, pneumococcal surface protein A (PspA) were characterized in C57BL/6 mice after heat-killed Streptococcus pneumoniae (HKSP) immunization and single or mixture herbicide exposure. Propanil exposure significantly increased the number of PC-specific IgM, IgG2b, and IgG3 antibody-secreting B cells (ASC) in the spleen 4-6-fold over control animals in a dose-dependent manner. However, the number of ASC in the bone marrow and serum titers were comparable in control and propanil-treated mice. In contrast, 2,4-D exposure decreased the number of PC-specific IgM and IgG bone marrow ASC 2-3-fold from control animals. The decrease in bone marrow ASC in 2,4-D-treated mice corresponded to a 3-4-fold decrease in PC-specific IgM, IgG2b, and IgG3 serum titers compared to control mice. The number of ASC in the spleens of 2,4-D-treated mice was, however, comparable to control mice. The antibody response to PspA was not affected by any of the treatments. There were no mixture interactions between the two herbicides in any of the responses measured. These results characterize the primary PC-specific antibody response in the bone marrow, spleen, and serum after HKSP vaccination and herbicide exposure. The differential effects of propanil and 2,4-D on the antibody response to a bacterial vaccine demonstrate the potential of chemical exposure to augment or suppress immune responses to vaccines and infectious diseases.

Characterization of thymic atrophy and the mechanism of thymocyte depletion after in vivo exposure to a mixture of herbicides.

3,4-Dichloropropionanilide (propanil) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two commonly used herbicides that are marketed as a chemical mixture. It was hypothesized that the interaction between these two herbicides, when administered as a mixture, would result in a greater effect on the immune system than the individual components of the mixture. The present study demonstrates in a murine model that a mixture of propanil and 2,4-D, when compared to single herbicide exposures, exacerbates decreases in thymocyte populations 2 d postexposure and inhibits the repopulation of T-cells in the thymus 7 d postexposure. Exposure to 150 mg herbicide/kg body weight of propanil or 2,4-D alone had no effect on thymus weight. In contrast, decreases in the ratio of thymus weight to body weight (TW:BW) occurred 2 d after treatment with the mixture of 150 mg propanil/kg body weight + 150 mg 2,4-D/kg body weight (150/150). Thymic atrophy was associated with a decrease in the double-positive thymocyte population (CD4+CD8+) and correlated with sera corticosterone levels from 600 to 1000 pg/ml. Therefore, the hypothesis was tested that glucocorticoids, induced after exposure to herbicides, were responsible for the thymic atrophy and depletion of thymocytes. However, similar levels of corticosterone were induced after exposure to 50, 100, or 150 mg propanil/kg body weight, and 50/50 or 100/100 mixture treatments, doses that did not produce thymic atrophy or cell loss. In addition, RU 486, a glucocorticoid receptor blocker, only partially abrogated the thymic atrophy in mice exposed to the 150/150 mixture of herbicides. These results suggest that glucocorticoids are only partially responsible for herbicide-induced thymic atrophy. This study demonstrates that the effects of exposure to a mixture of chemicals cannot always be predicted based on single exposure data and emphasizes the importance of mixture-based studies.

Loss of pre-B and IgM(+) B cells in the bone marrow after exposure to a mixture of herbicides.

This study determined alterations to bone marrow B-cell populations after in vivo exposure to a mixture containing the herbicides 3,4-dichloropropionanilide (propanil) and 2,4-dichlorophenoxyacetic acid (2,4-D) and compared them to the effects of exposure to the individual herbicides. Propanil and 2,4-D are postemergent herbicides that are sold commercially as a mixture. The individual herbicides or the mixture containing propanil and 2,4-D were administered intraperitoneally to C57Bl/6 female mice at doses from 50 to 200 mg herbicide/kg body weight. The mixtures were given in a 1:1 ratio. Flow cytometric analysis was performed to quantitate bone marrow B-cell populations at 1, 2, 7, and 14d posttreatment. Mixture treatment decreased pre-B and immunoglobulin (Ig) M(+) B-cell populations at all doses by 2 d postexposure. The cell populations were still decreased at 7d posttreatment. In contrast, exposure to the individual herbicides only caused decreases in the pre-B and IgM(+) B-cell populations 7d after exposure to the high doses. Previous studies have demonstrated that corticosterone levels are increased by exposure to propanil. Therefore, the glucocorticoid hormone, corticosterone, was investigated as a possible mediator of cell loss in the bone marrow. Treatment with the glucocorticoid receptor antagonist, RU 486, however, did not prevent cell loss in the bone marrow of mice exposed to the mixture of propanil and 2,4-D. This study demonstrates that pre-B and IgM(+) B-cell populations are decreased after exposure to propanil, 2,4-D, or the mixture containing propanil and 2,4-D. Exposure to the mixture had greater toxic effects than the individual herbicides on bone marrow pre-B and IgM(+) B-cell populations, emphasizing the need to study mixture interactions.