Biotic communities of freshwater marshes and mangroves in relation to saltwater incursions: implications for wetland regulation

An ecosystem-level study was conducted in the Guandu wetlands in subtropical coastal Taiwan to examine how salinity influences the abundance, diversity, and structure of biotic communities. We surveyed eight permanent study sites, spanning freshwater marshes, to the gate on the dyke, and mesohaline mangroves representing a gradient of the extent of saltwater incursions. Analyses of abiotic variables showed that salinity was the primary determining factor for discriminating habitat types in the wetlands, but communities differed in their sensitivity to salinity. The composition of plant and insect communities was most affected by the salinity gradient, suggesting the utility of these communities for ecological monitoring of saltwater incursions. However, spatial changes in communities at higher trophic levels, including macrobenthos, mollusks, fish, and birds, could not be explained simply by the salinity gradient. Instead, changes in these communities were more relevant to the composition of other biotic communities. Our results show that species richness and diversity of plant communities were higher in the marshes than in the mangroves. Nevertheless, insect communities censused in the mangroves had higher diversity, despite lower abundance and species richness. Macrobenthos surveyed in the mangroves showed higher biomass and number of taxa. Mollusks and fish were also more abundant at sites near the gate compared to the marsh sites. This suggests that maintaining a tidal flux by means of gate regulation is necessary for conserving the spatial heterogeneity and biodiversity of coastal wetlands

Canopy CO2 concentrations and Crassulacean acid metabolism in Hoya carnosa in a subtropical rain forest in Taiwan: consideration of CO2 avallability and the evolution of CAM in epiphytes

The potential importance of CO2 derived from host tree respiration at night as a substrate for night time CO2 uptake during CAM was investigated in the subtropical and tropical epiphytic vine Hoya carnosa in a subtropical rainforest in north-eastern Taiwan. Individuals were examined within the canopies of host trees in open, exposed situations, as well as in dense forests. Although night time CO2 concentrations were higher near the epiphytic vines at night, relative to those measured during the day, presumably the result Of CO2 added to the canopy air by the host tree, no evidence for substantial use of this CO2 was found. In particular, stable carbon isotope ratios of H. carnosa were not substantially lower than those of many other CAM plants, as would be expected if host-respired CO2 were an important source Of CO2 for these CAM epiphytes. Furthermore, laboratory measurements of diel CO2 exchange revealed a substantial contribution of daytime CO2 uptake in these vines, which should also result in lower carbon isotope values than those characteristic of a CAM plant lacking daytime CO2 uptake. Overall, we found that host-respired CO2 does not contribute substantially to the carbon budget of this epiphytic CAM plant. This finding does not support the hypothesis that CAM may have evolved in tropical epiphytes in response to diel changes in the CO2 concentrations within the host tree canopy

Multiplex Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR) for diagnosis of natural infection with canine distemper virus

<p>Abstract</p> <p>Background</p> <p>Canine distemper virus (CDV) is present worldwide and produces a lethal systemic infection of wild and domestic <it>Canidae</it>. Pre-existing antibodies acquired from vaccination or previous CDV infection might interfere the interpretation of a serologic diagnosis method. In addition, due to the high similarity of nucleic acid sequences between wild-type CDV and the new vaccine strain, current PCR derived methods cannot be applied for the definite confirmation of CD infection. Hence, it is worthy of developing a simple and rapid nucleotide-based assay for differentiation of wild-type CDV which is a cause of disease from attenuated CDVs after vaccination. High frequency variations have been found in the region spanning from the 3'-untranslated region (UTR) of the matrix (M) gene to the fusion (F) gene (designated M-F UTR) in a few CDV strains. To establish a differential diagnosis assay, an amplification refractory mutation analysis was established based on the highly variable region on M-F UTR and F regions.</p> <p>Results</p> <p>Sequences of frequent polymorphisms were found scattered throughout the M-F UTR region; the identity of nucleic acid between local strains and vaccine strains ranged from 82.5% to 93.8%. A track of AAA residue located 35 nucleotides downstream from F gene start codon highly conserved in three vaccine strains were replaced with TGC in the local strains; that severed as target sequences for deign of discrimination primers. The method established in the present study successfully differentiated seven Taiwanese CDV field isolates, all belonging to the Asia-1 lineage, from vaccine strains.</p> <p>Conclusions</p> <p>The method described herein would be useful for several clinical applications, such as confirmation of nature CDV infection, evaluation of vaccination status and verification of the circulating viral genotypes.</p

Comparative study of sustained-release lipid microparticles and solid dispersions containing ibuprofen

Ibuprofen is one of the most important non-steroidal anti-inflammatory drugs used in the treatment of inflammatory diseases. In its pure state, ibuprofen presents poor physical and mechanical characteristics and its use in solid dosage forms needs the addition of excipients that improve these properties. The selection of the best excipients and the most suitable pharmaceutical dosage form to carry ibuprofen is very important for the industrial success of this drug. Given these factors, lipid microparticles and solid dispersions of ibuprofen with cetyl alcohol, stearic acid, and hydrogenated castor oil were prepared. These formulations were intended to improve the physical and mechanical characteristics and to sustain the release of this drug. Physical mixtures were also prepared with the same ingredients in similar proportions. The solid dispersions of ibuprofen/stearic acid and ibuprofen/hydrogenated castor oil showed the best flow characteristics compared with pure ibuprofen. Further, gelatin capsules filled with lipid microparticles and solid dispersions were submitted to dissolution tests in order to study the influence of the prepared systems in the release profiles of ibuprofen. Prolonged release of ibuprofen was achieved with the lipid microparticles and solid dispersions prepared with the different types of excipients.O ibuprofeno é um dos antiinflamatórios não esteróides mais utilizados no tratamento de patologias associadas a processos inflamatórios. Este fármaco, quando no seu estado puro, apresenta características físicas e mecânicas pouco satisfatórias e a sua utilização em formas sólidas só é possível se forem adicionados excipientes que permitam melhorar estas propriedades. A seleção dos excipientes ideais e da forma farmacêutica mais adequada para veicular o ibuprofeno é fundamental para o sucesso industrial deste fármaco. Tendo em conta estes fatores, prepararam-se micropartículas lipídicas e dispersões sólidas de ibuprofeno com cada um dos seguintes excipientes: álcool cetílico, ácido esteárico e óleo de rícino hidrogenado. Estas formulações tinham por finalidade melhorar as características físicas e mecânicas e prolongar a liberação deste fármaco. Foram, também, preparadas misturas físicas do ibuprofeno com os mesmos excipientes e nas mesmas proporções. As dispersões sólidas de ibuprofeno/ácido esteárico e as dispersões sólidas de ibuprofeno/óleo de rícino hidrogenado foram aquelas que apresentaram melhores características de escoamento comparativamente com o ibuprofeno puro. Por outro lado, foram preparadas cápsulas de gelatina com as diferentes micropartículas lipídicas e dispersões sólidas e submetidas a ensaios de dissolução com o objetivo de estudar a influência dos sistemas preparados nos perfis de liberação do ibuprofeno. A liberação prolongada do ibuprofeno foi conseguida nas diferentes micropartículas lipídicas e dispersões sólidas preparadas com os diferentes excipientes

Use of solid dispersions to increase stability of dithranol in topical formulations

The present study was planned to improve the stability of dithranol using solid dispersions (SD). Two different SD at a 1:9 ratio of dithranol/excipient were prepared: one of them using glyceryl behenate as excipient and the other using a mixture of argan oil with stearic acid (1:8 ratio) as excipient. Pure dithranol and SD of dithranol were incorporated in an oil-in-water cream and in a hydrophobic ointment in a drug/dermatological base ratio of 1:10. The physical and mechanical properties of semisolid formulations incorporating the pure drug and the developed SD were evaluated through rheological and textural analysis. To evaluate the stability, L*a*b* color space parameters of SD and semisolid formulations, and pH of hydrophilic formulations were determined at defined times, during one month. Each sample was stored at different conditions namely, light exposure (room temperature), high temperature exposition (37 °C) (protected from light) and protected from light (room temperature). Despite higher values of firmness and adhesiveness, hydrophobic ointment exhibited the best rheological features compared to the oil-in-water cream, namely a shear-thinning behavior and high thixotropy. These formulations have also presented more stability, with minor changes in L*a*b* color space parameters. The results of this study indicate that is possible to conclude that the developed SD contributed to the increased stability of dithranol

Preparation and evaluation of azithromycin binary solid dispersions using various polyethylene glycols for the improvement of the drug solubility and dissolution rate

ABSTRACT Azithromycin is a water-insoluble drug, with a very low bioavailability. In order to increase the solubility and dissolution rate, and consequently increase the bioavailability of poorly-soluble drugs (such as azithromycin), various techniques can be applied. One of such techniques is "solid dispersion". This technique is frequently used to improve the dissolution rate of poorly water-soluble compounds. Owing to its low solubility and dissolution rate, azithromycin does not have a suitable bioavailability. Therefore, the main purpose of this investigation was to increase the solubility and dissolution rate of azithromycin by preparing its solid dispersion, using different Polyethylene glycols (PEG). Preparations of solid dispersions and physical mixtures of azithromycin were made using PEG 4000, 6000, 8000, 12000 and 20000 in various ratios, based on the solvent evaporation method. From the studied drug release profile, it was discovered that the dissolution rate of the physical mixture, as the well as the solid dispersions, were higher than those of the drug alone. There was no chemical incompatibility between the drug and polymer from the observed Infrared (IR) spectra. Drug-polymer interactions were also investigated using Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD) and Scanning Election Microscopy (SEM). In conclusion, the dissolution rate and solubility of azithromycin were found to improve significantly, using hydrophilic carriers, especially PEG 6000

Polymorphism: an evaluation of the potential risk to the quality of drug products from the Farmácia Popular Rede Própria

Polymorphism in solids is a common phenomenon in drugs, which can lead to compromised quality due to changes in their physicochemical properties, particularly solubility, and, therefore, reduce bioavailability. Herein, a bibliographic survey was performed based on key issues and studies related to polymorphism in active pharmaceutical ingredient (APIs) present in medications from the Farm&#225;cia Popular Rede Pr&#243;pria. Polymorphism must be controlled to prevent possible ineffective therapy and/or improper dosage. Few mandatory tests for the identification and control of polymorphism in medications are currently available, which can result in serious public health concerns