Showing papers by "Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto published in 1995"
Journal Article•
TL;DR: The results behaviorally and pharmacologically validate the elevated plus maze with transparent walls and suggest that this test could be a useful tool for the study of anxiolytic drugs and the neurobiology of anxiety.
Abstract: In this study we compared the performance of male Wistar rats, weighing 250-300 g, submitted to the standard plus maze (vertical surfaces of the closed arms with opaque walls) to their performance in a modified maze with raised Plexiglas edges in the closed arms (transparent walls). The animals (N = 12 for each group) continued to show a clear preference for the closed arms with transparent walls of the modified elevated plus maze. In addition, exploratory activity was higher in the open arms of the modified plus maze (4.25 +/- 0.42 entries and 53.50 +/- 5.10 s) as compared to that of the standard plus maze (2.10 +/- 0.25 entries and 24.00 +/- 4.91 s). Intraperitoneal injection of midazolam produced an increase in the number of entries (6.40 +/- 1.21 and 8.50 +/- 1.15 for 1.0 and 2.0 mg/kg, respectively) and in the time spend in the open arms (85.32 +/- 14.56 and 125.50 +/- 22.16 s for 1.0 and 2.0 mg/kg, respectively) while pentylenetetrazole caused a decrease in the number of entries (3.68 +/- 0.54 and 2.33 +/- 0.62 for 5.0 and 10 mg/kg, respectively) and in the time spent in the open arms of the modified maze (39.60 +/- 6.67 and 23.60 +/- 6.40 s for 5.0 and 10 mg/kg, respectively). The anxiolytic effect of midazolam and the anxiogenic effect of pentylenetetrazole were similar to those usually reported in the literature by authors using the standard test. These results behaviorally and pharmacologically validate the elevated plus maze with transparent walls and suggest that this test could be a useful tool for the study of anxiolytic drugs and the neurobiology of anxiety.
54 citations
TL;DR: The possibility that the soluble form of the enzyme, detected during endochondral ossification, would arise by the hydrolysis of the P1-anchored form of osseous plate alkaline phosphatase is discussed.
Abstract: Alkaline phosphatase activity was released up to 100% from the membrane by incubating the rat osseous plate membrane-bound enzyme with phosphatidylinositol-specific phospholipase C. The molecular weight of the released enzyme was 145,000 on Sephacryl S-300 gel filtration and 66,000 on PAGE-SDS, suggesting a dimeric structure. Solubilization of the membrane-bound enzyme with phospholipase C did not destroy its ability to hydrolyse PNPP, ATP and pyrophosphate. The hydrolysis of ATP and PNPP by phosphatidylinositol-specific phospholipase C-released enzyme exhibited ‘Michaelian’ kinetics with K0.5=70 and 979 μM, respectively. For pyrophosphate, K0.5 was 128 μM and site-site interactions were observed (n=1.4). Magnesium ions were stimulatory (K0.5=1.5 mM) and zinc ions were a powerful noncompetitive inhibitor (Ki=6.2 μM) of phosphatidylinositol-specific phospholipase C-released enzyme. Phosphatidylinositol-specific phospholipase C-released alkaline phosphatase was relatively stable at 40°C. However, with increasing temperature from 40–60°C, the enzyme was inactivated rapidly following first order kinetics and thermal inactivation constants varied from 5.08×10−4 min−1 to 0.684 min−1. Treatment of phosphatydilinositol-specific phospholipase C-released alkaline phosphatase with Chellex 100 depleted to 5% its original PNPPase activity. Magnesium (K0.5=29.5 μM), manganese (K0.5=5 μM) and cobalt ions (K0.5=10.1 μM) restored the activity of Chelex-treated enzyme, demonstrating its metalloenzyme nature. The stimulation of Chelex-treated enzyme by calcium ions (K0.5=653 μM) was less effective (only 26%) and occurred with site-site interactions (n=0.7). Zinc ions had no stimulatory effects. The possibility that the soluble form of the enzyme, detected during endochondral ossification, would arise by the hydrolysis of the P1-anchored form of osseous plate alkaline phosphatase is discussed.
52 citations
TL;DR: The human head dynamic response to side impact by finite element modelling, e.g. viscoelastic material in a rigid spherical shell--a rotational head injury model, is studied.
Abstract: axisymmetric vibrations of a spheroidal model of the head,' J. Biomech., 9, pp. 803-812 LIU, Y. K., CHANDRAN, K. B., and VoN ROSENBURG, D. U. (1975): 'Angular Acceleration of viscoelastic(kelvin) material in a rigid spherical shell--a rotational head injury model,' J. Biomech., 8, pp. 285-292 MERCHANT, H. C., and C~uSPtNO, A. J. (1974): \"A dynamic analysis of an elastic model of the human head,' .I. Biomech., 7, pp. 295-301 MISRA, J. C., and CI~,KRAVARrHY, S. (1984): 'A study on rotational brain injury,' J. Biomech., 7, pp. 459-466 NmA, (1990): Numerically Integrated Element for System Analysis, Engineering Mechanics Research Centre, Michigan Ntnu Ag.g.AS (1975): 'Dynamic analysis of a fluid filled spherical sandwich shell--a model of the human head,' J Biomech., 8, pp. 275-284 RUAN, J. S., KHALIL, T. B., and KING, A. I. (1991): 'Human head dynamic response to side impact by finite element modelling,' ASME J Biomech. Eng., 113, pp. 276-283 SHUGAR, T. A., and KATONA, M. G. (1975): 'Development of finite element model of the human head.' ASCE EM3, 109, E173, pp. 223-239 WARD, C. C., N[KRAVESH, P. E., and THOMPSON, IL B. (1978): 'Biodynamie finite element models used in brain injury research,' J Aviation Space, Env. Med., pp. 136-142 WARD, C. C., L--'KAN, M., and NAHUM, A. (1981): 'InWacranial pressure----a brain injury criterion.' Proc. 24th STAPP Car Crash Conf., pp. 163-185
51 citations
TL;DR: Production was maximal for Humicola grisea var.
Abstract: β-d-Xylosidase production was maximal for Humicola grisea var. thermoidea grown on xylan as the sole carbon source. The main β-d-xylosidase activity was localised in the periplasm. β-Xylosidase was purified from crude extracts by heat treatment, ammonium sulfate precipitation and chromatography on DEAE-cellulose and Sephadex G-100. The purified enzyme was a monomer of molecular mass estimated to be 43 kDa by SDS-PAGE and gel filtration. Optima of pH and temperature were 6.0 and 50 °C, respectively. The enzyme activity was stimulated by Ca2+, Fe2+, and Mg2+. The purified β-xylosidase did not exhibit xylanase, carboxymethylcelullase, galactosidase, glucosidase, fucosidase or arabinosidase activities. The purified β-xylosidase hydrolysed xylobiose and xylo-oligosaccharides of up to five monosaccharide units. The enzyme had a Km of 0.49 mM for p-nitrophenyl-β-d-xylopyranoside and was not inhibited by its product, xylose.
46 citations
TL;DR: In this article, β-dicarbonyl and β-cyanocaronyl compounds were dimenzed chemically by CAN or by electrocatalysis using cerous nitrate as mediator.
34 citations
TL;DR: Results argued against the participation of the periplasmic trehalase of N. crassa in the catabolism of intracellular trehalose, and are also conflictant with the enzyme/substrate decompartmentation hypothesis.
30 citations
TL;DR: A lyoluminescence reader was constructed and the response of irradiated dl -alanine and sucrose was investigated as a function of the sensitizer concentration, solution pH, mass of material and absorbed dose.
30 citations
23 citations
TL;DR: Rats living in a laboratory foraging paradigm began each meal by bar pressing to procure access to food and then could eat any amount, and saved foraging cost at the expense of greater-than-normal daily fluctuations in food intake and body weight.
16 citations
TL;DR: Polidocanol-solubilized osseous plate alkaline phosphatase was modulated by cobalt ions in a similar way as by magnesium ions, and a steady-state kinetic model for the modulation of enzyme activity by Cobalt ions is proposed.
6 citations
Journal Article•
TL;DR: The data show that this relatively simple and inexpensive SQUID biogradiometer can be used for noninvasive in utero investigation of fetal heart activity without requiring a special environment.
Abstract: The magnetic field produced by the fetal heart magnetocardiogram (FMCG) was measured by a single channel SQUID biogradiometer in an unshielded environment. FMCG amplitude ranged from 1 to 4 pT. Instantaneous fetal heart rate and averaged FMCG waveforms were computed. Spectral analysis was used to quantify fetal heart rate variability, and revealed peaks from 0.5 to 1.0 Hz, consistent with respiratory sinus arrhythmia. The duration of the QRS complex was approximately 50 msec, and its amplitude and shape showed strong spatial variation. Signal-to-noise ratio was inadequate for the study of P and T waves. These data show that this relatively simple and inexpensive instrument can be used for noninvasive in utero investigation of fetal heart activity without requiring a special environment.
Journal Article•
TL;DR: Results indicate the importance of Zn 2+ before and during pregnancy and show that Zn2+ deficiency causes metabolic alterations which impair normal reproductive processes.
Abstract: The objective of the present study was to determine the consequences of Zn2+ deficiency on the gestational process. The study was conducted on adult Wistar virgin female rats fed isocaloric diets containing 16% protein and different Zn2+ concentrations, i.e., 2 ppm (severe restriction), 6 ppm (moderate restriction), and 20 ppm (control). Rats received the diets and water ad libitum for 7, 14 or 21 days before mating and throughout pregnancy. Survival of dams and pups decreased with increasing Zn2+ restriction and with time of exposure to the deficient diet. Mean survival rate for control dams and pups was 100%, whereas severe restriction (2 ppm for 21 days premating and during pregnancy) resulted in survival rates of 25% and 0 for dams and pups, respectively. Dam and pup survival rates for moderate restriction (6 ppm) for the same period were 83% and 72%, respectively. These results indicate the importance of Zn2+ before and during pregnancy and show that Zn2+ deficiency causes metabolic alterations which impair normal reproductive processes.
TL;DR: In this article, the cyclohexane ring adopts a chair conformation and the cis-fused cyclo-hexanone ring is in a slightly distorted chair-conformity.
Abstract: C14H22O3,M r
=238.33, P212121,Z=4,a=6.892(2),b=11.453(1),c=17.159(5) A. [1R−[1α(R*), 4β, 4aβ, 8aβ]]−α,4-Dimethyl-decahydro-7-oxo-1-naphtaleneacetic acid. The cyclohexane ring adopts a chair conformation and thecis-fused cyclohexanone ring is in a slightly distorted chair conformation. The molecular packing involves an hydrogen bond and C−H...O contacts.