Relative potency of different generic brands of meropenem, colistin and fosfomycin: Implications for antimicrobial therapy and antimicrobial formulary

There is a need of a relatively simple and inexpensive method for the determination of relative potency of various generic brands of antibiotics in comparison to original products. The current study describes an agar diffusion method which can be performed in any microbiology laboratory, is cheap (costs $2 per test) and its results can be available after overnight incubation. The results show that neither all generics are reliable nor are all generic antibiotics of poor quality.

Encefalopatía traumática crónica, definición, diagnóstico y prevención: revisión de la literatura / Chronic traumatic encephalopathy, definition, diagnosis and prevention: review of literature

La encefalopatía traumática crónica (ETC) es una enfermedad neurodegenerativa que se produce como consecuencia traumatismos cerebrales repetitivos; concusiones, que son un síndrome clínico que se caracteriza por una alteración de la función cerebral. Una concusión, bajo su estricta definición, no debiese causar cambios estructurales en el cerebro por lo que no sería visible a través de imágenes, sí existen cambios a nivel microscópicos, bioquímicos y biomecánicos. La mayoría de los pacientes tienen completa resolución de sus síntomas dentro de 10 días (90 por ciento), pero existe un pequeño porcentaje que persiste con estos, pudiendo presentarse como un síndrome postconcusional, síndrome de segundo impacto o una encefalopatía traumática crónica. La ETC se caracteriza por la acumulación de prot-tau hiperfosforilada en neuronas y astrocitos. Estas se van a presentar en forma de ovillos o hilos neurofibrilares. En etapas iniciales las encontraremos de forma focalizada en la corteza frontal y en las formas más severas su distribución será más generalizada, distribuyéndose en la mayoría de las regiones del cerebro. Su diagnóstico se realiza a través de histopatología, por lo que hasta el momento sólo se ha logrado post-mortem. Se está trabajando en nuevas tecnologías asociadas a biomarcadores y PET para lograr una diagnostico premortem. El mayor énfasis en el manejo de esta taupatía es la prevención y adecuado manejo de las concusiones.

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease which is produced as a consequence of repeated brain trauma: concussions, which are a clinical syndrome characterized by an alteration in brain functions. A concussion, understrict definition, should not cause structural changes to the brain. Therefore, it would not be possible to see through images if there were changes at a microscopic, biochemical level. Most patients see their symptoms completely resolved within 10 days (90 percent), but there is a small percentage which persists, and these might cause a post-concussional syndrome, second impact syndrome of chronic traumatic encephalopathy. CTE is characterized by the accumulation of hyper-phosphorylated Tau protein in neurons and astrocytes. These appear in the form of neurofibrillary tangles. During the initial stages they are focalized in the frontal cortex and, in more severe cases, their distribution is more generalized, spreading through the majority of the regions in the brain. It is diagnosis is done through histopathology. Thus, it has only been possible to do post mortem. New technologies associated with bio-markers and PET are being worked on to achieve a pre-mortem diagnosis. The greatest emphasis in the handling of this tauopathy lies in the prevention and the adequate handling of concussions.

Cadmium tolerance and antibiotic resistance in Escherichia coli isolated from waste stabilization ponds.

The incidence pattern of cadmium tolerance and antibiotics resistance by Escherichia coli was examined periodically from the samples of water, sludge and intestine of fish raised in waste stabilization ponds in a sewage treatment plant. Samples of water and sludge were collected from all the selected ponds and were monitored for total counts of fecal coliform (FC), total coliform (TC) and the population of Escherichia coli, which was also obtained from the intestine of fishes. Total counts of both FC and TC as well as counts of E. coli were markedly reduced from the facultative pond to the last maturation pond. Tolerance limit to cadmium by E. coli tended to decline as the distance of the sewage effluent from the source increased; the effective lethal concentration of cadmium ranged from 0.1 mM in split chamber to 0.05 mM in first maturation pond. E. coli isolated from water, sludge and fish gut were sensitive to seven out of ten antibiotics tested. It appears that holistic functions mediated through the mutualistic growth of micro algae and heterotrophic bacteria in the waste stabilization ponds were responsible for the promotion of water quality and significant reduction of coliform along the sewage effluent gradient.

O ciclo da vesícula sináptica, espinhos dendríticos e a transdução de sinal / Synaptic vesicle cycle, dendritic spines and signal transduction

No sistema nervoso, a sinapse é a estrutura que permite a um neurônio passar um sinal elétrico ou químico a outro neurônio ou outra célula (muscular ou glandular). A palavra sinapse vem de "synaptein", palavra que Sir Charles Scott Sherrington e seus colegas acunharam do grego "syn" (junto) e "haptein"(afivelar). As sinapses podem ser separadas entre elétricas e químicas, porém a maior parte da transmissão sináptica é realizada através das sinapses químicas. Apesar das sinapses químicas terem uma resposta mais lenta que as elétricas, elas possuem a vantagem da amplificação do sinal gerada através de uma cascata de segundos mensageiros. As sinapses químicas podem ser excitatórias ou inibitórias e são caracterizadas por um terminal pré-sináptico (onde estão presentes as vesículas que contêm os neurotransmissores) em contato com um terminal pós-sináptico (onde estão presentes os receptores ionotrópicos e metabotrópicos para esses neurotransmissores) separados pela fenda sináptica. As sinapses típicas acontecem sobre axônios (axo-axônicas), sobre dendritos (axo-dendríticas), sobre o soma de outro neurônio (axo-somáticas) e sobre os espinhos dendríticos...

In the nervous system, the synapse is the structure that allows a neuron pass an electrical or chemical signal to another neuron or another cell (muscle or glandular). The word synapse comes from "synaptein" that Sir Charles Scott Sherrington and his colleagues minted from the Greek "syn" (together) and "haptein"(buckling). Most part of the synaptic transmission is performed through chemical synapses. Chemical synapses have a slower response than the electric ones; they have the advantage of amplifying the signal generated through a cascade of second messengers. Chemical synapses can be excitatory or inhibitory and are characterized by a presynaptic terminal (where there are vesicles that contain the neurotransmitters) in contact with a postsynaptic terminal (where there are the ionotropic and metabotropic receptors) separated by the synaptic cleft. Synapses can occur on axons (axo-axonal), on dendrites (axodendritic), on soma (axo-somatic) and on dendritic spines...

Neurotransmissão glutamatérgica e plasticidade sináptica: aspectos moleculares, clínicos e filogenéticos / Glutamatergic neurotransmission and synaptic plasticity: molecular, clinical, and phylogenetic aspects

A comunicação entre neurônios é passível de constantes modificações, até mesmo no encéfalo adulto. Esta capacidade de circuitos neuronais fortalecerem ou enfraquecerem suas interações sinápticas específicas (fenômeno conhecido como plasticidade sináptica) pode ocorrer de acordo com as diferentes demandas ambientais, o que favorece a noção de que alterações dinâmicas na comunicação entre neurônios estão na base da flexibilidade comportamental (i.e., processos de aprendizagem e memória). Nas últimas décadas, o avanço das neurociências tem permitido uma melhor compreensão a respeito da plasticidade sináptica, especialmente a plasticidade de sinapses glutamatérgicas, cujos processos moleculares de modificação sináptica parecem estar entre os mais comuns de todo o sistema desse progresso na ciência básica tem contribuído para uma melhor compreensão acerca dos processos patológicos envolvendo as sinapses glutamatérgicas, como a doença de Alzheimer. Além disso, a crescente compreensão sobre o funcionamento da comunicação glutamatérgica tem ajudado a esclarecer como as sinapses, em geral, teriam se originado e evoluído na escala filogenética do reino animal (Metazoa)...

Communication between neurons is subject to constant changes, even in the adult brain. This ability of neural circuits to strengthen or weaken their specific synaptic interactions (a phenomenon known assynaptic plasticity) may occur according to different environmental demands, which favors the idea that dynamic changes in the communication between neurons underlie behavioral flexibility (i.e., learning and memory processes). In recent decades, advances in neuroscience has allowed a better understanding of synaptic plasticity, specially the plasticity of glutamatergic synapses, whose molecular processes of synaptic change appear to be among the most common throughout the central nervous system.Much of this progress in basic science has contributed to a better understanding of pathological processes involving the glutamatergic synapses, such as Alzheimer's disease. Furthermore, the growing understanding about the physiology of glutamatergic communication has helped explain how synapses, in general, would have originated and evolved in the phylogenetic scale of the Metazoa...

Cadmium tolerance and antibiotic resistance of Pseudomonas sp. isolated from water, sludge and fish raised in wastewater-fed tropical ponds.

The numbers of Pseudomonas sp. isolated were counted in samples collected from water, sludge and intestine of fishes raised in different wastewater ponds along an effluent gradient in a sewage treatment plant. Total fish yield in the last maturation pond increased by 73% over the yield in first maturation pond or facultative pond. The number of Pseudomonas sp. isolated from the intestine of the tilapia (Oreochromis mssambicus) raised in facultative pond, was more than three times the counts (7.22 × 108/g) observed in the last maturation pond (2.025 × 108/g). The effective lethal concentration of cadmium for Pseudomonas sp. isolated from the intestine of the tilapia was 0.6 mM and 0.08-0.09 mM when the fish was procured from facultative pond and last maturation pond, respectively. The Pseudomonas sp. isolated from the intestine of the tilapia did not have resistance to any of the ten antibiotics tested. However, the bacterium isolated from raw sewage, water and sediment of the anaerobic pond was resistant to seven out of ten antibiotics tested.

Responses of succinate dehydrogenase and non-specific alkaline phosphatases and mortality of tilapia to ambient pH stress in a sewage-fed aquaculture pond.

The fish, tilapia (Oreochromis mossambicus) of 50-60 g body weight was experimentally exposed to effluent gradients of highly alkaline pH in a sewage-fed aquaculture farm for examining the pH stress-induced responses of mortality and the stress marker enzyme succinate dehydrogenase and the non-specific alkaline phosphatases of fish prior to death at different hours of intoxication. A second trial was performed after two months when water quality changed along the sewage effluent gradient. An in situ experiment was also performed for better understanding of the responses of enzymatic activities attributable to different levels of pH conditions. Time required for 100% mortality of fish tended to increase from 30 min in pH 11.6 to 22 hr in pH 10.2. There was no mortality of fish when water quality improved significantly (with pH ranging between 9.6 to 8.0) after two months. The activities of succinate dehydrogenase and intracellular alkaline phosphatases assayed in gills and liver prior to death of fish tended to reduce with increase in survival hour, following a pattern of decay curve. On the other hand, percent of enzymatic inhibition of the exposed fish over the control increased as the survival hour increased following a pattern of exponential curve. It appears that the highest water pH of 11.6. maximum ratio for ammonium to ammonium hydroxide (1: 21) and reduced level of dissolved oxygen (2.62 mg/l) were perhaps responsible for the 100% mortality of fish within 30 min of their exposure and the enzymatic activities in the gills and liver assayed prior to death of fish tended to reduce as the acclimatization period of fish increased and vice-versa.

Oxygen uptake and filtration rate as animal health biomarker in Lamellidens marginalis (Lamarck).

The freshwater bivalve, L. marginalis was experimentally exposed to 10 and 30 ppm concentrations of CdCl2 to examine filtration rate, oxygen uptake and glycogen level of liver and gills for health assessment for their reuse in the reclamation of cadmium intoxicated environments. In situ experiment was also performed for better appraisal of the filtration rate in the lake. Oxygen uptake in the treated group exceeded that of control by 15-22% during the early 24 hr after cadmium exposure, but followed an essential decline (23-30%) thereafter. The reduction of filtration rate ranged from 12-62% in laboratory to 83-85% in field trials. At the tissue level, glycogen content was reduced by 61-72% in liver and 52-63% in gill. In both tissues, glycogen content was inversely proportional to the cadmium contents of the animal. Critical appraisal of data suggests that the threshold values of cadmium in gill and liver were 50-80 microg/g dw for oxygen uptake and 50-60 microg/g for filtration rate because of marked reduction of these parameters beyond the values of cadmium. It is concluded that filtration rate, oxygen uptake of the freshwater bivalve, L. marginalis can be used as biomarker for animal health assessment and for possible reuse of the stock animals.