Axial Diffusivity of the Corona Radiata at 24 Hours Post-Stroke: A New Biomarker for Motor and Global Outcome

Fractional anisotropy (FA) is an effective marker of motor outcome at the chronic stage of stroke yet proves to be less efficient at early time points. This study aims to determine which diffusion metric in which location is the best marker of long-term stroke outcome after thrombolysis with diffusion tensor imaging (DTI) at 24 hours post-stroke. Twenty-eight thrombolyzed patients underwent DTI at 24 hours post-stroke onset. Ipsilesional and contralesional FA, mean (MD), axial (AD), and radial (RD) diffusivities values were calculated in different Regions-of-Interest (ROIs): (1) the white matter underlying the precentral gyrus (M1), (2) the corona radiata (CoRad), (3) the posterior limb of the internal capsule (PLIC) and (4) the cerebral peduncles (CP). NIHSS scores were acquired at admission, day 1, and day 7; modified Rankin Scores (mRS) at 3 months. Significant decreases were found in FA, MD, and AD of the ipsilesional CoRad and M1. MD and AD were also significantly lower in the PLIC. The ratio of ipsi and contralesional AD of the CoRad (CoRad-rAD) was the strongest diffusion parameter correlated with motor NIHSS scores on day 7 and with the mRS at 3 months. A Receiver-Operator Curve analysis yielded a model for the CoRad-rAD to predict good outcome based on upper limb NIHSS motor scores and mRS with high specificity and sensitivity. FA values were not correlated with clinical outcome. In conclusion, axial diffusivity of the CoRad from clinical DTI at 24 hours post-stroke is the most appropriate diffusion metric for quantifying stroke damage to predict outcome, suggesting the importance of early axonal damage.     

Temperature coupling in cricket acoustic communication

Summary Temperature effects on calling song production and recognition were investigated in the North American field cricket, Gryllus firmus. Temporal parameters of field-recorded G. firmus calling song are strongly affected by temperature. Chirp rate and syllable rate increase, by factors of 4 and 2, respectively, as linear functions of temperature over the range in which these animals sing in the field (12°–30 °C). Temperature affects syllable duration to a lesser extent, and does not influence calling song carrier frequency. Female phonotactic preference, measured on a spherical treadmill in the laboratory, also changes with temperature such that warmer females prefer songs with faster chirp and syllable rates. Best phonotaxis, measured as accuracy of orientation to the sound source, and highest walking velocity, occur in response to temperature-matched songs at 15°, 21°, and 30 °C. Experiments under semi-natural conditions in an outdoor arena revealed that females perform phonotaxis at temperatures as low as 13 °C. Taken together, the song and phonotaxis data demonstrate that this communication system is temperature coupled. A strategy is outlined by which temperature coupling may be exploited to test hypotheses about the organization of neural networks subserving song recognition.Abbreviations CP chirp period - SP syllable period - SD syllable duration     

Improving protein extraction yield in reversed micellar systems through surface charge engineering

The mechanism of extraction of rat cytochrome b(5) from water into a sodium dioctylsulfosuccinate (AOT) micellar organic phase was studied using protein engineering of surface charged residues. The extraction behavior of native cytochrome b(5) and modified proteins with substitutions of the type glutamic acid --> lysine at positions 44 (E44K), 56 (E56K), and 92 (E92K), was studied as a function of pH. The results indicate that an important mechanism of extraction is an electrostatic interaction of this protein with the negatively charged surfactant. We demonstrate that it is possible to improve extraction by engineering the protein surface charge, increasing the driving force responsible for the protein transfer to the micellar phase. (c) 1994 John Wiley & Sons, Inc.     

Survey of bovine mycotic mastitis in dairy herds in the State of São Paulo,Brazil

The purpose of this study was to isolate fungi from the quarter milk of cow udders from several dairy herds and to identify the different genera and species involved in mastitis. A total of 2078 milk samples from normal, clinical and subclinical mastitis quarters from 22 dairy herds of 16 districts in the State of São Paulo, Brazil was utilized in this survey. Two hundred and fifty one (12.07%) fungi were isolated from the samples. Two hundred and eight of these (82.86%) were yeasts and 30 (11.95%) were moulds. The fungi were isolated in pure culture (24.77%) or in cultures mixed with bacteria (72.22%). The yeasts isolated were:Cryptococcus spp. (71 strains),Rhodotorula spp. (40),Candida spp. (68),Trichosporon cutaneum (21),Aureobasidium pullulans (7), andPichia ohmeri (1). Moulds classified in following genera were also isolated:Aspergillus (3),Penicillium (3),Alternaria (3),Phoma (3),Epicoccum (2), andGeotrichum (16).     

Natural lignin modulators improve bagasse saccharification of sugarcane and energy cane in field trials

The burgeoning cellulosic ethanol industry necessitates advancements in enzymatic saccharification, effective pretreatments for lignin removal, and the cultivation of crops more amenable to saccharification. Studies have demonstrated that natural inhibitors of lignin biosynthesis can enhance the saccharification of lignocellulose, even in tissues generated several months post-treatment. In this study, we applied daidzin (a competitive inhibitor of coniferaldehyde dehydrogenase), piperonylic acid (a quasi-irreversible inhibitor of cinnamate 4-hydroxylase), and methylenedioxy cinnamic acid (a competitive inhibitor of 4-coenzyme A ligase) to 60-day-old crops of two conventional Brazilian sugarcane cultivars and two energy cane clones, bred specifically for enhanced biomass production. The resultant biomasses were evaluated for lignin content and enzymatic saccharification efficiency without additional lignin-removal pretreatments. The treatments amplified the production of fermentable sugars in both the sugarcane cultivars and energy cane clones. The most successful results softened the most recalcitrant lignocellulose to the level of the least recalcitrant of the biomasses tested. Interestingly, the softest material became even more susceptible to saccharification.     

The vegetable rennet of Cynara cardunculus L. contains two proteinases with chymosin and pepsin-like specificities

The flowers of cardoon (genus Cynara) are traditionally used in Portugal for cheese making. In this work the vegetable rennet of the species Cynara cardunculus L. was characterized in terms of enzymic composition and proteolytic specificity of its proteinases (cardosin A and cardosin B). Cardosin A was found to cleave insulin B chain at the bonds Leu15-Tyr16, Leu17-Val18 and Phe25-Tyr26. In addition to the bonds mentioned cardosin B cleaves also Glu13-Ala14, Ala14-Leu15 and Phe24-Phe25 indicating that it has a broader specificity. The kinetic parameters for the hydrolysis of the synthetic peptide Leu-Ser-Phe(NO₂)-Nle-Ala-Leu-oMe were also determined and compared to those of chymosin and pepsin. The results obtained indicate that in terms of specificity and kinetic parameters cardosin A is similar to chymosin whereas cardosin B is similar to pepsin. It appears therefore that the enzyme composition of cardoon rennet closely resembles that of calf rennet.     

Purification and properties of myosin light-chain kinase from fast skeletal muscle.

1. A procedure is described for the isolation of myosin light-chain kinase from rabbit fast skeletal muscle as a homogeneous protein. 2. Myosin light-chain kinase is a monomeric enzyme of mol.wt. 77000. Under some conditions of storage it is converted into components of mol.wts. about 50000 and 30000 that possess enzymic activity. 3. The enzyme is clearly different in structure and properties from any other protein kinase so far isolated from muscle. 4. The enzyme is highly specific for the P-light chain (18000-20000-dalton light chain) of myosin and requires Ca2+ for activity. 5. The P-light chain is phosphorylated at a similar rate whether isolated or associated with the rest of the myosin molecule. 6. The effects of pH, bivalent cation and other nucleotides on the enzymic activity are described. 7. The role of the phosphorylation of the P-light chain of myosin in muscle function is discussed.     

Prevalence, biotypes, plasmid profile and antimicrobial resistance of Campylobacter isolated from wild and domestic animals from northeast Portugal.

The incidence of Campylobacter jejuni and Campylobacter coli in wild and producing animals has been studied to evaluate their importance as potential reservoirs of campylobacter infection. These organisms were isolated from: 59 chicken (60.2%), 65 swine (59.1%), 31 black rats (57.4%), 61 sparrows (45.5%), 21 ducks (40.5%), 32 cows (19.5%) and 27 sheep (15.3%). Biotypes, plasmid and resistance profiles were studied in order to characterize the isolates. Biotypes I and II of C. jejuni were predominant in all reservoirs except swine, where C. coli I was more frequent. Plasmid prevalence was higher in strains isolated from swine (53.8%) and rats (45.5%). The size of the plasmids ranged from 1.3 to 82 MDa. A 2.3 MDa plasmid was the most frequent, detected in all the reservoirs except ducks. Antimicrobial susceptibility testing revealed that 5.5% of the strains were resistant to ampicillin, 5.5% to tetracycline, 12.6% to erythromycin and 23.5% to streptomycin. Resistance to erythromycin (26.2%) and to streptomycin (58.4%) was particularly high in isolates from swine. Tetracycline resistance was encoded by a 33 or a 41 MDa plasmid and transferred by conjugation.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Luminescence properties of the Ln–EDTA complexes covalently linked to the chitosan biopolymers containing β‐diketonate as antenna ligands

This paper reports on the preparation, characterization, and photoluminescence properties of novel hybrid materials, in which the EDTA–Ln–L complexes (where L: H₂O, acac, bzac, dbm, and tta ligands, and Ln: Eu, Gd, and Tb) were covalently linked to the precursor medium molecular weight chitosan surface (CS) matrices or on the chitosan surfaces previously crosslinked with epichlorohydrin (CSech). The emission spectra of these materials were characterized by intraconfigurational‐4fN transitions centred on the Eu³⁺ and Tb³⁺ ions. Some broad bands from the polymeric matrix were also observed in the emission spectra, however the relative intensities of the intraconfigurational bands increased significantly for systems containing diketonate ligands when the antenna effect became more efficient. The values of the radiative rates (A_rad) were higher for crosslinked hybrid systems with epichlorohydrin, while nonradiative rates (A_nrad) presented the opposite behaviour. These data contributed to an increase in the values of emission quantum efficiency (η) for crosslinked materials. The effect of the modification process and antenna ligand on the values of intensities, intensity parameters Ω₂ e Ω₄ of the Eu³⁺ complexes were also investigated. The results showed that the crosslinked biopolymer surfaces have great potential for applications in molecular devices light converters.