Lumbar muscle electromyographic dynamic topography during flexion-extension

The objective of this study is to introduce dynamic topography of surface electromyography (SEMG) to visualize lumbar muscle myoelectric activity and provides a new view to analyze muscle activity in vivo. A total of 20 healthy male subjects and 15 males LBP were enrolled. An electrode-array was applied to the lumbar region to collect SEMG. The root mean square (RMS) value was calculated for each channel, and then a 160×120 matrix was constructed using a linear cubic spline interpolation of each scan to create a 2-D color topographic image. Along a definite interval of action, a series of RMS topography matrices was concatenated as a function of position and time, to form a dynamic topographical video of lumbar muscle activity. Relative area (RA), relative width (RW), relative height (RH) and Width-to-Height Ratio (W/H) were chosen as the four quantitative parameters in measuring topographic features. Normal RMS dynamic topography was found to have a consistent, symmetric pattern with a high intensity area in the paraspinal area. LBP patients had a different RMS dynamic topography, with an asymmetric, broad, or disorganized distribution. Quantitative SEMG features were found significantly different between normal control and LBP. After physiotherapy rehabilitation, the dynamic topography images of LBP tended towards the normal pattern.There are obvious differences in lumbar muscle coordination between healthy subjects and LBP patients. The dynamic topography allows the continuous visualization of the distribution of surface EMG signals and the coordination of muscular contractions.     

Evolution and functional divergence of the anoctamin family of membrane proteins

Background  

The anoctamin family of transmembrane proteins are found in all eukaryotes and consists of 10 members in vertebrates. Ano1 and ano2 were observed to have Ca²⁺ activated Cl^- channel activity. Recent findings however have revealed that ano6, and ano7 can also produce chloride currents, although with different properties. In contrast, ano9 and ano10 suppress baseline Cl^- conductance when co-expressed with ano1 thus suggesting that different anoctamins can interfere with each other. In order to elucidate intrinsic functional diversity, and underlying evolutionary mechanism among anoctamins, we performed comprehensive bioinformatics analysis of anoctamin gene family.     

Serotonin synthesis,release and reuptake in terminals: a mathematical model

Background  

Serotonin is a neurotransmitter that has been linked to a wide variety of behaviors including feeding and body-weight regulation, social hierarchies, aggression and suicidality, obsessive compulsive disorder, alcoholism, anxiety, and affective disorders. Full understanding of serotonergic systems in the central nervous system involves genomics, neurochemistry, electrophysiology, and behavior. Though associations have been found between functions at these different levels, in most cases the causal mechanisms are unknown. The scientific issues are daunting but important for human health because of the use of selective serotonin reuptake inhibitors and other pharmacological agents to treat disorders in the serotonergic signaling system.     

Sheep prions with molecular properties intermediate between classical scrapie,BSE and CH1641–scrapie

Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641–a rare scrapie variant–could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrP^res) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrP^res found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrP^res population. The existence of these 2 PrP^res populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing.     

Three novel ABCC5 splice variants in human retina and their role as regulators of ABCC5 gene expression

Background  

The ABCC5 gene encodes an organic anion pump of the ATP-binding cassette (ABC) transporter family, subclass C. The exact physiological function of ABCC5 however is not known. Here, we have isolated three novel ABCC5 splice variants and characterized their role in the regulation of ABCC5 gene expression.     

Flavin-dependent thymidylate synthase ThyX activity: implications for the folate cycle in bacteria

Although flavin-dependent ThyX proteins show thymidylate synthase activity in vitro and functionally complement thyA defects in heterologous systems, direct proof of their cellular functions is missing. Using insertional mutagenesis of Rhodobacter capsulatus thyX, we constructed the first defined thyX inactivation mutant. Phenotypic analyses of the obtained mutant strain confirmed that R. capsulatus ThyX is required for de novo thymidylate synthesis. Full complementation of the R. capsulatus thyX::spec strain to thymidine prototrophy required not only the canonical thymidylate synthase ThyA but also the dihydrofolate reductase FolA. Strikingly, we also found that addition of exogenous methylenetetrahydrofolate transiently inhibited the growth of the different Rhodobacter strains used in this work. To rationalize these experimental results, we used a mathematical model of bacterial folate metabolism. This model suggests that a very low dihydrofolate reductase activity is enough to rescue significant thymidylate synthesis in the presence of ThyX proteins and is in agreement with the notion that intracellular accumulation of folates results in growth inhibition. In addition, our observations suggest that the presence of flavin-dependent thymidylate synthase X provides growth benefits under conditions in which the level of reduced folate derivatives is compromised.     

The control of body size in insects

Control mechanisms that regulate body size and tissue size have been sought at both the cellular and organismal level. Cell-level studies have revealed much about the control of cell growth and cell division, and how these processes are regulated by nutrition. Insulin signaling is the key mediator between nutrition and the growth of internal organs, such as imaginal disks, and is required for the normal proportional growth of the body and its various parts. The insulin-related peptides of insects do not appear to control growth by themselves, but act in conjunction with other hormones and signaling molecules, such as ecdysone and IDGFs. Size regulation cannot be understood solely on the basis of the mechanisms that control cell size and cell number. Size regulation requires mechanisms that gather information on a scale appropriate to the tissue or organ being regulated. A new model mechanism, using autocrine signaling, is outlined by which tissue and organ size regulation can be achieved. Body size regulation likewise requires a mechanism that integrates information at an appropriate scale. In insects, this mechanism operates by controlling the secretion of ecdysone, which is the signal that terminates the growth phase of development. The mechanisms for size assessment and the pathways by which they trigger ecdysone secretion are diverse and can be complex. The ways in which these higher-level regulatory mechanisms interact with cell- and molecular- level mechanisms are beginning to be elucidated.     

Impact of ivermectin on onchocerciasis transmission: assessing the empirical evidence that repeated ivermectin mass treatments may lead to elimination/eradication in West-Africa

BACKGROUND: The Onchocerciasis Control Program (OCP) in West Africa has been closed down at the end of 2002. All subsequent control will be transferred to the participating countries and will almost entirely be based on periodic mass treatment with ivermectin. This makes the question whether elimination of infection or eradication of onchocerciasis can be achieved using this strategy of critical importance. This study was undertaken to explore this issue. METHODS: An empirical approach was adopted in which a comprehensive analysis was undertaken of available data on the impact of more than a decade of ivermectin treatment on onchocerciasis infection and transmission. Relevant entomological and epidemiological data from 14 river basins in the OCP and one basin in Cameroon were reviewed. Areas were distinguished by frequency of treatment (6-monthly or annually), endemicity level and additional control measures such as vector control. Assessment of results were in terms of epidemiological and entomological parameters, and as a measure of inputs, therapeutic and geographical coverage rates were used. RESULTS: In all of the river basins studied, ivermectin treatment sharply reduced prevalence and intensity of infection. Significant transmission, however, is still ongoing in some basins after 10-12 years of ivermectin treatment. In other basins, transmission may have been interrupted, but this needs to be confirmed by in-depth evaluations. In one mesoendemic basin, where 20 rounds of four-monthly treatment reduced prevalence of infection to levels as low as 2-3%, there was significant recrudescence of infection within a few years after interruption of treatment. CONCLUSIONS: Ivermectin treatment has been very successful in eliminating onchocerciasis as a public health problem. However, the results presented in this paper make it almost certain that repeated ivermectin mass treatment will not lead to the elimination of transmission of onchocerciasis from West Africa. Data on 6-monthly treatments are not sufficient to draw definitive conclusions.     

Elements of butterfly wing patterns

The color patterns on the wings of butterflies are unique among animal color patterns in that the elements that make up the overall pattern are individuated. Unlike the spots and stripes of vertebrate color patterns, the elements of butterfly wing patterns have identities that can be traced from species to species, and typically across genera and families. Because of this identity it is possible to recognize homologies among pattern elements and to study their evolution and diversification. Individuated pattern elements evolved from non-individuated precursors by compartmentalization of the wing into areas that became developmentally autonomous with respect to color pattern formation. Developmental compartmentalization led to the evolution of serially repeated elements and the emergence of serial homology. In these compartments, serial homologues were able to acquire site-specific developmental regulation and this, in turn, allowed them to diverge morphologically. Compartmentalization of the wing also reduced the developmental correlation among pattern elements. The release from this developmental constraint, we believe, enabled the great evolutionary radiation of butterfly wing patterns. During pattern evolution, the same set of individual pattern elements is arranged in novel ways to produce species-specific patterns, including such adaptations as mimicry and camouflage.