Sincronismo muscular en patrones de movimiento de miembros superiores descritos por Kabat: latencia al inicio del pico de la máxima activación electromiográfica / Muscle timing in upper limb movement patterns described by Kabat: Latency at the beginning of the peak of maximum electromyographic activation

Introducción El método Kabat sostiene que el sincronismo normal se produce de distal a proximal, lo cual requiere evidencia electromiográfica. Objetivo Describir el sincronismo muscular de patrones motores de miembros superiores descritos por Kabat, en posiciones sedente y supina, a partir de la medición de la latencia al inicio del pico de la máxima activación electromiográfica (IPMA-EMG) de músculos seleccionados. Material y métodos Se realizó un estudio analítico comparativo. Se evaluó a 20 hombres y 20 mujeres entre 19 y 26 años. Cada participante realizó 3repeticiones activas sin resistencia externa de cada uno de los patrones de movimiento (flexor y extensor) de las 2diagonales. Se registró la latencia del IPMA-EMG para cada uno de los 8músculos evaluados en los 4patrones de movimiento, tanto en supino como en sedente. Estos se promediaron y se ordenaron de menor a mayor para obtener la secuencia de contracciones musculares en cada patrón de movimiento. Se compararon las secuencias obtenidas para cada patrón en sedente y supino y se valoró la existencia de correlaciones entre ellas. Resultados Se observó correlación significativa en las secuencias del IPMA-EMG entre posiciones supina y sedente, en todos los patrones de movimiento (p<0,05), excepto en el patrón extensor de la primera diagonal (p=0,139). No hubo diferencias estadísticamente significativas entre posiciones en ninguno de los patrones (p>0,05). Conclusiones Aunque con variaciones en la IPMA-EMG, se halló, en general, un sincronismo muscular de proximal a distal, más evidenciado en la posición sedente y en los patrones flexores (AU)

Introduction The Kabat method argues that normal synchronism occurs from distal to proximal, which requires electromyographic evidence. Objective To describe the muscular timing of motor patterns of the upper limbs described by Kabat, in seated and supine positions, from the measurement of the latency at the beginning of the peak of the maximum electromyographic activation (BPM-EMG-A) of selected muscles. Material and methods A comparative analytical study was carried out. Twenty men and 20 women between 19 and 26 years old were evaluated. Each participant performed 3active repetitions without external resistance of each of the movement patterns (flexor and extensor) of the 2diagonals. BPM-EMG-A latency was recorded for each of the 8muscles tested in the 4movement patterns, both supine and seated. These were averaged and ordered from lowest to highest to obtain the sequence of muscle contractions in each movement pattern. The sequences obtained for each pattern in seated and supine were compared and the existence of correlations between them was assessed. Results Significant correlation was observed in the BPM-EMG-A sequences between supine and seated positions, in all movement patterns (P<0.05), except in the extensor pattern of the first diagonal (P=0.139). There were no statistically significant differences between positions in any of the patterns (P>0.05). Conclusion Although with variations in BPM-EMG-A, muscle timing was generally found from proximal to distal, more evident in the sitting position and in flexor patterns (AU)

Glutathione depletion sensitizes cisplatin- and temozolomide-resistant glioma cells in vitro and in vivo.

Malignant glioma is a severe type of brain tumor with a poor prognosis and few options for therapy. The main chemotherapy protocol for this type of tumor is based on temozolomide (TMZ), albeit with limited success. Cisplatin is widely used to treat several types of tumor and, in association with TMZ, is also used to treat recurrent glioma. However, several mechanisms of cellular resistance to cisplatin restrict therapy efficiency. In that sense, enhanced DNA repair, high glutathione levels and functional p53 have a critical role on cisplatin resistance. In this work, we explored several mechanisms of cisplatin resistance in human glioma. We showed that cellular survival was independent of the p53 status of those cells. In addition, in a host-cell reactivation assay using cisplatin-treated plasmid, we did not detect any difference in DNA repair capacity. We demonstrated that cisplatin-treated U138MG cells suffered fewer DNA double-strand breaks and DNA platination. Interestingly, the resistant cells carried higher levels of intracellular glutathione. Thus, preincubation with the glutathione inhibitor buthionine sulfoximine (BSO) induced massive cell death, whereas N-acetyl cysteine, a precursor of glutathione synthesis, improved the resistance to cisplatin treatment. In addition, BSO sensitized glioma cells to TMZ alone or in combination with cisplatin. Furthermore, using an in vivo model the combination of BSO, cisplatin and TMZ activated the caspase 3-7 apoptotic pathway. Remarkably, the combined treatment did not lead to severe side effects, while causing a huge impact on tumor progression. In fact, we noted a remarkable threefold increase in survival rate compared with other treatment regimens. Thus, the intracellular glutathione concentration is a potential molecular marker for cisplatin resistance in glioma, and the use of glutathione inhibitors, such as BSO, in association with cisplatin and TMZ seems a promising approach for the therapy of such devastating tumors.

Acridones as antiviral agents: synthesis, chemical and biological properties.

Acridones are a class of compounds that have attracted attention in recent years for their wide range of biological properties, including selective inhibition of diverse human pathogenic viruses. The wide spectrum of antiviral activity includes DNA and RNA viruses, such as herpes simplex virus, cytomegalovirus, adenovirus, hepatitis C virus, dengue virus, and Junin virus, among others, indicative of the involvement of cellular factors as potential targets of acridone derivatives. At the present, their precise mode of action is not clearly determined, although the predominant action seems to be centered on the synthesis of nucleic acids. Regarding this point, inhibitory activity against cellular and viral enzymes and the ability to intercalate into nucleic acid molecules was demonstrated for some acridone compounds. Then, the possibility of a multiple effect on different targets renewed interest in these agents for virus chemotherapy allowing a potent inhibitory effectiveness associated to less feasibility of generating antiviral resistance. This review summarizes the current knowledge regarding the methods of synthesis, the antiviral properties of acridone derivatives, their mechanism of action, and structural characteristics related to antiviral activity as well as the perspectives of this class of compounds for clinical application against human viral infections.

Contrast-enhanced dynamic magnetic resonance nephrography in healthy dogs.

Twenty-three healthy mixed-breed male adult dogs were examined using serial magnetic resonance (MR) renograms. The images were obtained using a dynamic gradient-echo, fast SPGR, T1-weighted sequence and low doses of gadolinium chelates (0.025 mmol/kg). Time-intensity curves were obtained to assess typical urinary excretion parameters, namely, time to vascular peak (TVP), time to vascular drop (TVD), time to glomerular peak (TGP), parenchymal phase length (PPL), gradient of parenchymal phase (GPP) and pattern of excretory segment. The mean TVP, TVD, TGP and PPL were 31.6±11.8, 43.4±11.2, 154.0±36.2 and 115.2±37.7s, respectively. The GPP was 24.1±8.6% of signal intensity per min. The excretory segment was concave in all cases, and at the end of the examination, 87.1% of kidneys had shown a reduction in signal intensity of 50%. This MR nephrography protocol can provide adequate time-intensity curve parameters for the urinary system of dogs, offers excellent anatomical detail, and represents an alternative to radionuclide nephrography.

AMPA receptor downregulation induced by ischaemia/reperfusion is attenuated by age and blocked by meloxicam.

AIM: Stroke prevalence increases with age, while alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) and inflammation have been related to ischaemia-induced damage. This study shows how age and treatment with an anti-inflammatory agent (meloxicam) modify the levels of AMPAR subunits GluR1 and GluR2, as well as the mRNA levels of the GluR2-editing enzyme, ADAR2, in a global brain ischaemia/reperfusion (I/R) model. METHODS: Two days after global ischaemia CA1, CA3, dentate gyrus and cerebral cortex were obtained from sham-operated and I/R-injured 3- and 18-month-old Sprague-Dawley rats. Real time polymerase chain reaction, Western blotting and immunohistochemical assays were performed. Meloxicam treatment was assayed on young animals. RESULTS: Data showed that age attenuates the downregulation induced by I/R in the AMPAR subunits GluR1 and GluR2 and modifies the GluR1/GluR2 mRNA level ratio in a structure-dependent way. The study of the ADAR2 mRNA levels showed more downregulation in older animals than young ones. Meloxicam treatment prevented the transcriptional arrest induced by I/R. CONCLUSION: Our data suggest that changes in the AMPAR isoforms could be associated with ageing in the different structures studied. Although GluR2 editing seems to be involved in age-dependent vulnerability to ischaemia supporting the 'GluR2 hypothesis', this alone does not explain the differential vulnerability in the different brain regions. Finally, inflammation could play a role in protection from I/R-induced injury.

100% efficient sub-nanoliter sample introduction in laser-induced breakdown spectroscopy and inductively coupled plasma spectrometry: implications for ultralow sample volumes.

Recently, nanoflow nebulizers with low-volume drain-free spray chambers became available for inductively coupled plasma-mass spectrometry application for analysis of very small sampling volumes. The present technical note reports on a different approach for 100% efficient subnanoliter sample introduction, the application of monodisperse piezoelectric microdroplet dispensers which generate 40-50 microm droplets with high reproducibility if nozzles of 30 microm diameter are applied. The droplets having volumes below 0.1 nL can be introduced loss-free and without plasma loading, with frequencies up to approximately 100 Hz into analytical plasmas. In this technical note, the analytical figures of merit of laser-induced breakdown spectroscopy and inductively coupled plasma-optical emission spectrometry with single droplet introduction are reported using Ca and Au standard solutions as examples. Future engineering is required to reduce the total sample volumes from the relatively large sample reservoir of the current study, thereby reducing potential issues of washout while enabling analysis of ultralow total sample volumes.

An antiviral disulfide compound blocks interaction between arenavirus Z protein and cellular promyelocytic leukemia protein.

The promyelocytic leukemia protein (PML) forms nuclear bodies (NB) that can be redistributed by virus infection. In particular, lymphocytic choriomeningitis virus (LCMV) influences disruption of PML NB through the interaction of PML with the arenaviral Z protein. In a previous report, we have shown that the disulfide compound NSC20625 has antiviral and virucidal properties against arenaviruses, inducing unfolding and oligomerization of Z without affecting cellular RING-containing proteins such as the PML. Here, we further studied the effect of the zinc-finger-reactive disulfide NSC20625 on PML-Z interaction. In HepG2 cells infected with LCMV or transiently transfected with Z protein constructs, treatment with NSC20625 restored PML distribution from a diffuse-cytoplasmic pattern to punctate, discrete NB which appeared identical to NB found in control, uninfected cells. Similar results were obtained in cells transfected with a construct expressing a Z mutant in zinc-binding site 2 of the RING domain, confirming that this Z-PML interaction requires the integrity of only one zinc-binding site. Altogether, these results show that the compound NSC20625 suppressed Z-mediated PML NB disruption and may be used as a tool for designing novel antiviral strategies against arenavirus infection.

Early modifications in N-methyl-D-aspartate receptor subunit mRNA levels in an oxygen and glucose deprivation model using rat hippocampal brain slices.

Glutamatergic N-methyl-d-aspartate NMDA receptors (NMDAR) are considered to play a key role in ischemia-induced damage. Long-term (hours) changes in their expression upon ischemia have been shown. Here we report short-term changes in the mRNA levels of the major hippocampal NMDAR subunits (NR1, NR2A and NR2B), as well as c-fos, in an ex vivo ischemia model using hippocampal slices. This effect can be observed also in a calcium free incubation solution. Striking early decreases in the NMDAR subunit mRNA levels were observed after 30 min of oxygen and glucose deprivation (OGD) as well as a partial recovery when the tissues were returned to the balanced salt solution (reperfusion-like period) for 3 h. Since OGD-induced damage has been reported to be a consequence of the increase in OGD-related glutamate release, we also analyzed NMDAR mRNA levels following increased glutamate levels in hippocampal sections in which no significant effects on NMDAR subunit mRNA levels were detected. Furthermore, we describe that the presence of MK-801 (a selective NMDAR antagonist), CNQX (a selective AMPA/kainate receptor antagonist) or their combined action in the incubation solution is able to induce a significant decrease in NMDAR expression but in these conditions the OGD does not induce further decreases in mRNA levels. We suggest that the mechanisms triggered during OGD to downregulate mRNA levels of NMDAR subunits could be the same than those induced by glutamate receptor antagonists.

Zn finger containing proteins as targets for the control of viral infections.

The zinc finger proteins have fascinated many research groups because of their modular assembly, broad range of biological functions and more recently because they are attractive targets for antiviral therapy. The zinc finger domain is a very stable structural element whose hallmark is the coordination of a zinc ion by several amino acid residues, usually cysteines and histidines. These structural motifs are associated with protein-nucleic acid recognition as well as protein-protein interactions. The biological function of the zinc finger proteins is strongly dependent on the zinc ion, which assure integrity and stability. Thus, the disruption of critical zinc finger viral proteins represents a fundamentally new approach to inhibit viral replication in the absence of mutations leading to drug resistance phenotypes. This review summarizes the drug design and potential therapeutic applications of viral zinc fingers disrupting agents for the control of viral diseases.

Identification of a mutation in synapsin I, a synaptic vesicle protein, in a family with epilepsy.

A four generation family is described in which some men of normal intelligence have epilepsy and others have various combinations of epilepsy, learning difficulties, macrocephaly, and aggressive behaviour. As the phenotype in this family is distinct from other X linked recessive disorders linkage studies were carried out. Linkage analysis was done using X chromosome microsatellite polymorphisms to define the interval containing the causative gene. Genes from within the region were considered possible candidates and one of these, SYN1, was screened for mutations by direct DNA sequencing of amplified products. Microsatellite analysis showed that the region between MAOB (Xp11.3) and DXS1275 (Xq12) segregated with the disease. Two point linkage analysis demonstrated linkage with DXS1039, lod score 4.06 at theta = 0, and DXS991, 3.63 at theta = 0. Candidate gene analysis led to identification of a nonsense mutation in the gene encoding synapsin I that was present in all affected family members and female carriers and was not present in 287 control chromosomes. Synapsin I is a synaptic vesicle associated protein involved in the regulation of synaptogenesis and neurotransmitter release. The SYN1 nonsense mutation that was identified is the likely cause of the phenotype in this family.

Virucidal activity of essential oils from aromatic plants of San Luis, Argentina.

Essential oils obtained from eight aromatic plants of San Luis Province, Argentina, were screened for virucidal activity against herpes simplex virus type 1 (HSV-1), Junin virus (JUNV) and dengue virus type 2 (DEN-2). The most potent inhibition was observed with the essential oil of Lippia junelliana and Lippia turbinata against JUNV with virucidal concentration 50% (VC(50)) values in the range 14-20 ppm, whereas Aloysia gratissima, Heterotheca latifolia and Tessaria absinthioides inhibited JUNV in the range 52-90 ppm. The virucidal activity was time- and temperature-dependent. The essential oils of A. gratissima, Artemisia douglasiana, Eupatorium patens and T. absinthioides inactivated HSV-1 at 65-125 ppm. However, only A. douglasiana and E. patens had any discernible effect on DEN-2 infectivity with VC(50) values of 60 and 150 ppm, respectively.

A simple procedure to perform intravenous injections in the Mongolian gerbil (Meriones unguiculatus).

We describe a simple and feasible procedure for performing intravenous administration of substances in the gerbil. Under light anaesthesia, animals were held in dorsal recumbency and a very small incision of skin, parallel to the femoral vein on the internal side of the thigh, was made. The vein is easily accessible via thin skin incision. An insulin syringe and a 30 G needle were used for the injection. This is an easy and quick method, which, with appropriate anaesthesia, allows rapid recovery.

Mode of inactivation of arenaviruses by disulfide-based compounds.

Several disulfide-based compounds, including intermolecular aromatic disulfides of the type Ph-S-S-Ph and dithianes with the sulfur atoms tethered in a ring structure, have shown effective inhibitory activity against the arenaviruses Junin (JUNV), agent of Argentine hemorrhagic fever, and Tacaribe (TCRV). These compounds showed a strong virucidal effect with inactivating concentration 50% (IC(50)) values in the range 0.6-5.0 microM, and also were effective to reduce virus yields from infected cells. The mode of inactivating action of two active compounds, the aromatic bis disulfide NSC20625 and the dithiane NSC624152, was further studied. Both compounds were able to inactivate arenaviruses after a few minutes of direct contact with virions, in a concentration- and time-dependent manner. The ability of drug-treated virus to perform several steps of the replication cycle was analyzed. The killed virus particles were found to bind and enter to Vero cells with the same efficacy as infectious native virions, but the ability of inactivated virions to synthesize viral proteins in Vero cells was abolished. Thus, treatment of JUNV and TCRV with these compounds destroyed virion infectivity, generating particles which entered the host cell but were unable to complete the viral biosynthetic processes.

Time-resolved laser-induced plasma spectrometry for determination of minor elements in steelmaking process samples.

A pulsed Nd:YAG laser operating on the fourth (266 nm) and second (532 nm) harmonics has been used to generate plasmas on the target surface in air at atmospheric pressure. The influence of wavelength on quantitative analysis of 4 minor elements in stainless steel samples (Si, Ti, Nb and Mo) was investigated. Stainless steel samples with different elemental concentrations were prepared and analyzed by laser-induced plasma spectrometry (LIPS). The effect of laser wavelength on analytical figures of merit (calibration curves, correlation coefficients, linear dynamic ranges, analytical precision, and accuracy values) was found to be negligible when internal standardization (an Fe line) and time-resolved laser-induced plasma are employed. For both wavelengths, the calibration curves presented a good linearity and an acceptable linear dynamic range in the concentration interval investigated. For the four elements studied, limits of detection lower than 150 microg g(-1) were achieved. To evaluate the influence of wavelength on precision and accuracy, a set of fifteen high-alloyed steel samples from different stages of steelmaking process have been analyzed. Finally, the long-term stability of the analytical measurements for Mo with 532 nm wavelength has been discussed. RSD values were lower than 5.3% for the elements studied.

Microbiological quality and safety of ready-to-eat cooked foods from a centralized school kitchen in Argentina.

The purpose of this study was to evaluate the microbiological and sensory quality as well as the safety of ready-to-eat (RTE) cooked foods prepared in and distributed from a centralized kitchen to schools in Argentina. A total of 101 cooked food samples delivered as hot RTE cooked foods (group A) and as RTE cooked foods at room temperature (group B) and 140 surface swab environment samples were collected from February to November 1999. Petrifilm plates were used for aerobic (PAC), coliform (PCC), and Escherichia coli (PEC) counts. Standard methods were used to determine Enterobacteriaceae (EntC) and thermotolerant coliform counts (TCC). Samples were also tested for the presence of Salmonella spp., Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens. Food temperatures just before samples were put into containers ranged from 80 to 98 degrees C and from 28 to 32 degrees C for group A and group B, respectively. For group A food samples, PAC ranged from 1.04 to 3.50 log CFU/g, and PCC, PEC, TCC, and EntC were not detected. For group B food samples, PAC ranged from 3.63 to 6.48 log CFU/g, PCC ranged from 1.90 to 5.36 log CFU/g, TCC ranged from 1.30 to 3.95 log CFU/g, and EntC ranged from 3.60 to 5.46 log CFU/g. Of the foodborne pathogens, only B. cereus was isolated (63.4% of samples) in both food groups (<4 log CFU/g). The microbiological and sensory quality and the safety of group A foods were satisfactory. Large numbers of PAC and EntC detected in group B foods show that better control is needed to avoid potential foodborne diseases.

Evaluation of the antiviral activity against Junin virus of macrocyclic trichothecenes produced by the hypocrealean epibiont of Baccharis coridifolia.

Four macrocyclic trichothecenes, roridin A, roridin E, verrucarin A and verrucarin J, produced by the hypocrealean epibiont of Baccharis coridifolia, were evaluated for their inhibitory activity against the arenavirus Junin (JUNV), the etiological agent of Argentine hemorrhagic fever. The trichothecenes achieved a dose-dependent inhibition of JUNV multiplication at concentrations not affecting cell viability. The 50 % inhibitory concentration (IC50) values determined by a virus yield inhibition assay were in the range 1.2 - 4.9 ng/ml. The most active compound was verrucarin J which reduced JUNV yield more than 2 log units and had a similar effect against the arenavirus Tacaribe. The trichothecenes lacked virucidal effects on JUNV virions. From time of addition and removal experiments, it can be concluded that verrucarin J inhibited a late stage in the replicative cycle of JUNV, after 5 h of adsorption.

Effect of fatty acids on arenavirus replication: inhibition of virus production by lauric acid.

To study the functional involvement of cellular membrane properties on arenavirus infection, saturated fatty acids of variable chain length (C10-C18) were evaluated for their inhibitory activity against the multiplication of Junin virus (JUNV). The most active inhibitor was lauric acid (C12), which reduced virus yields of several attenuated and pathogenic strains of JUNV in a dose dependent manner, without affecting cell viability. Fatty acids with shorter or longer chain length had a reduced or negligible anti-JUNV activity. Lauric acid did not inactivate virion infectivity neither interacted with the cell to induce a state refractory to virus infection. From mechanistic studies, it can be concluded that lauric acid inhibited a late maturation stage in the replicative cycle of JUNV. Viral protein synthesis was not affected by the compound, but the expression of glycoproteins in the plasma membrane was diminished. A direct correlation between the inhibition of JUNV production and the stimulation of triacylglycerol cell content was demonstrated, and both lauric-acid induced effects were dependent on the continued presence of the fatty acid. Thus, the decreased insertion of viral glycoproteins into the plasma membrane, apparently due to the increased incorporation of triacylglycerols, seems to cause an inhibition of JUNV maturation and release.

Diagnosis of renal agenesis in a beagle.

A case of right renal agenesis in a beagle, of interest because of the age of the dog at the time of diagnosis, is described. Physical, haematological, biochemical and urinary examinations, including measurement of endogenous creatinine clearance, were performed to assess renal function. Survey radiography, excretory urography, ultrasonography, computed tomography and nuclear magnetic resonance examinations were also used to confirm the absence of a kidney. The effect of kidney agenesis on renal function, evaluated on the basis of endogenous creatinine clearance, is discussed together with the benefits of the various imaging techniques to enable in vivo detection of renal abnormalities.

Antiviral and virucidal activities against arenaviruses of zinc-finger active compounds.

Fifteen antiretroviral Zn-finger active compounds with diverse chemical structures, including azoic compounds, hydrazide derivatives, disulphide-based reagents and others were screened in vitro against Junin virus (JUNV), the aetiological agent of Argentine haemorrhagic fever, by a virus yield inhibition assay in Vero cells. Cytotoxicity was evaluated simultaneously by the MTT method. Of the compounds, three were totally inactive as antivirals, nine presented moderate anti JUNV-activity and three were truly active with EC50 (effective concentration 50%) values in the range 6.5-9.3 microM and with selectivity indices greater than 10. The most active inhibitors, named NSC20625, 3-7 and 2-71, demonstrated a broad range of action against arenaviruses, including several attenuated and pathogenic strains of JUNV as well as the antigenically related Tacaribe virus (TACV) and Pichinde virus (PICV). The direct treatment of JUNV and TACV virions with the compounds showed two types of behaviour: the aromatic disulphide NSC20625 was a very potent virucidal agent, whereas the other two compounds exhibited moderate or negligible virus-inactivating properties.