Lactate sequestration by osteoderms of the broad-nose caiman, Caiman latirostris, following capture and forced submergence

Lactate accumulation in osteoderms; of the broad-nose caiman, Caiman latirostris, was determined following capture and surgery and after a period of forced submergence and related to concurrent values in blood. Control samples of bone and blood were taken after recovery from surgery and before submergence. In addition, samples of osteoderm were incubated in a lactate solution to determine equilibrium concentration, and additional samples were analyzed for elemental and CO2 concentrations. The composition of the osteoderms closely resembles that of typical vertebrate bone, with a high concentration of calcium and phosphate. Plasma and osteoderm lactate concentrations were both elevated following surgery and decreased significantly after 1 day of recovery. Submergence produced a typical lactate pattern in the plasma, with only a modest increase during the dive and then a sharp increase during recovery to a peak of 31.2 +/- 1.9 mumol ml(-1) after 1 h. When caimans were anesthetized 2 h after submergence, osteoderm lactate in the same animals was significantly increased to 14.8 mumol g(-1) wet mass. The ratio of the osteoderm: plasma lactate concentration after submergence was similar to the ratio observed in the incubated samples, suggesting that osteoderm lactate concentrations in vivo were equilibrated with circulating plasma levels. We conclude that caiman osteoderms sequester lactate during lactic acidosis and that the time course is fast enough to have benefit to these animals following normal anaerobic burst activity.

Effects of calcium gluconate and PMSF in the treatment of acute intoxication of chicken by TOCP

To examine the efficacy of calcium gluconate (two doses of Ca-Glu 5 mg/kg i.v.) to alleviate the injurious effects of organophosphorus induced delayed neuropathy (OPIDN) in the presence or absence of phenylmethanesulfonyl fluoride (PMSF go mg/kg i.m.), 14 groups of four isabrown hens were used. To measure the lymphocyte neuropathy target esterase (LNTE)activity, groups receiving just distilled water (control), groups receiving just Tri-orto-cresyl phosphate (TOCP; 500 mg/kg p.o.) (Positive control), and other groups receiving TOCP and Ca-Glu or PMSF simultaneously or 12 hours later following intoxication by TOCP were used. They were sacrificed 12 and 24 hours after the administration of TOCP. To observe a 28-day time course of neurotoxicity scores and calcium plasma concentration, five groups were used. Regarding free Ca(2+)in the plasma, the positive control produced a characteristic profile time course up and down (luring 28 days, and some hens with maximum score of neurotoxicity in 28 days. The treatment, which prevented greater oscillation in free Ca(2+) in the plasma, presented a decrease in OPIDN in relation to the positive control. Twelve hours after the administration of TOCP, LNTE was 70-80% inhibited when compared with control, whereas the first decrease in the free Ca(2+) in the plasma was significantly different from the control only 24 hours after the administration of TOCP. In summary, the sooner the Ca-Glu is started, the less severe the neuropathy effects.

Estudo clínico e níveis de ansiedade em uma série de casos de líquen plano oral

Oral Lichen Planus (OLP) is a relatively common, cronic inflammatory disease. Its etiopathogenesis is no completely understood and several factors have proposed in attempt to explain the appearance, variety of clinical manifestations and periods of exacerbation and remission of the symptons of the lesions. The objective of the present study was to assess the presence of local factors, systemic diseases and levels of anxiety in patients with OLP, investigating their association with the clinical characteristics of the lesions. The sample consisted of 37 patients with histopathologically confirmed OLP that were submitted to a clinical exam to evaluate the presence of smoking habits, consumption of alcoholic beverages, diabetes mellitus, hypertension and hepatitis C virus (HCV) infection. The existence of skin lesions, as well as the time course, clinical form, symptomatology, number and location of the oral lesions were also registered. The trait anxiety was measured by Spielberger s Stai-Trait Anxiety Inventory (STAI), and to associate the variables we used the chi-square or Fisher s exact test. It was observed that females were the most affected (75%) and the mean age of the patients was 53,3 years. Most cases were non-smoker (97,3%) and none was drinker. Diabetes mellitus and hypertension were present in 10,8% e 16,2% of the sample, respectively and only one patient was HCV-seropositive (2,7%). Moderate levels of anxiety were seen in most cases (78,4%) and 21,6% had elevated levels. The oral lesions persisted in 95% of the cases for a period of 6 months to 13 years. The erosive form was the most prevalent (57,1%) and symptons were reported by 45,7% of the patients. Multiple lesions were frequent (60%), affecting mainly the buccal mucosa, followed by gums e tongue. There was no significant association of the presence of diabetes mellitus, hypertension and levels of anxiety with the clinical form or symptomatology of the oral lesions (p>0,005), despite a trend in patients with hypertension to have erosive lesions. It was concluded that, in the sample studied, moderate levels of anxiety were commonly observed, and the HCV infection apparently is not related to the onset of the OLP. In this study, the presence of diabetes mellitus, hypertension and levels of anxiety seem not to be associated with the clinical characteristics of the lesions of OLP

Oscilações Teta no hipocampo do rato durante tarefa de tomada de decisão espacial

The processing of spatial and episodic information during memory tasks depends on hippocampal theta oscillations. In the present study, I investigated the relationship between theta power and choice selection during spatial decision-making. I recorded local field potentials from the CA1 region of rats retrieving reward locations in a 4-arm maze. In trained but not in naïve animals, I observed a significant increase in theta power during decision-making, which could not be explained by changes in locomotion speed. Furthermore, a Bayesian decoder based on theta power predicted choice outcomes in speed-matched trials. The decoding time course revealed that performance increased above chance before the decision moment exclusively for theta power, remaining flat for other frequency bands. These results occurred for trained animals, but no significant prediction could be made for naïve animals. Altogether, the data support a mnemonic function of theta rhythm during spatial decision-making, indicating that these oscillations correlate with the retrieval of memories required for successful decisions

Effects of castration and of testosterone replacement on alpha(1)-adrenoceptor subtypes in the rat vas deferens

The contractions of the rat vas deferens in response to noradrenaline are mediated through alpha(1A)-adrenoceptors. We observed participation of alpha(1B)-adrenoceptors in these contractions after castration. We now investigated the time course of this plasticity and the effects of testosterone by determining the actions of competitive antagonists on noradrenaline-induced contractions after 7, 14, 21 and 30 days of castration. BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride) antagonised noradrenaline-induced contractions in control and castrated rats with low pA(2) values (congruent to 6.8). In control vas deferens, WB 4101 (2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride) had a slope in the Schild plot no different from 1.0, while slopes lower than 1.0 ( approximate to 0.6) were observed for vas deferens from castrated rats. Chloroethylclonidine was ineffective in the control vas while it inhibited noradrenaline-induced contractions in vasa from castrated rats and converted the complex antagonism by WB 4101 into simple competitive antagonism. Treatment of castrated rats with testosterone prevented the effects of castration. The results suggest that alpha(1B)-adrenoceptors are detectable in vas deferens from at least the 7th through the 30th day after castration and that testosterone prevents this plasticity. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Germinação de sementes de Drymaria cordata (L.) Willd. ex Roem & Schult.: efeito do potencial hídrico

Modelos matemáticos baseados no conceito de graus dia (thermal-time) e Ψw dia (hydrotime) podem ser usados para a elaboração de modelos mais gerais sobre a germinação e emergência de plântulas no campo, podendo ser uma importante ferramenta para estudos sobre a biologia de plantas daninhas e seu controle. Neste trabalho, avaliou-se a germinação de sementes de D. cordata em resposta ao potencial hídrico (Ψw), usando-se o modelo Ψw dia. Tanto a germinabilidade como a velocidade de germinação decresceram linearmente com a redução do Ψw, atingindo valores próximos a zero em -0.8 MPa. em temperatura ótima, a taxa de queda na germinação foi maior em comparação com as temperaturas sub- e supra-ótima. O Ψw base (Ψwb) mediano foi similar entre as temperaturas sub-ótima (19 ºC) e supra-ótima (32 ºC), mas foi maior (menos negativo) à temperatura ótima (25 ºC), mostrando que sementes de D. cordata são menos sensíveis à redução do potencial hídrico à 19 ºC do que à 25 ºC. O Ψw dia foi maior para sementes germinadas à temperatura sub-ótima do que à temperatura ótima, mostrando que a velocidade de germinação num dado potencial hídrico é maior em temperatura ótima. A quantidade de Ψw dia necessária para a germinação foi maior em temperatura supra-ótima do que em temperatura ótima, e menor em temperatura supra-ótima do que em sub-ótima. em geral, Ψw dia foi relativamente constante entre as diferentes sub-populações. O modelo de Ψw dia pode descrever bem o efeito do potencial hídrico sobre as curvas de germinação (porcentagem acumulada x tempo), especialmente às temperaturas sub-ótima e supra-ótima.

Endogenous annexin A1 counter-regulates bleomycin-induced lung fibrosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oxidation of chalcopyrite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in shake flasks

Chalcopyrite oxidation was evaluated with two acidophilic thiobacilli that are important in bioleaching processes. Acidithiobacillus thiooxidans in pure culture did not oxidize CuFeS2 but oxidized externally added S in the presence of CuFeS2. Acidithiobacillus ferrooxidans released Cu2+ and soluble Fe from chalcopyrite, and the time course lead to a gradual passivation of chalcopyrite whereby Cu2+ dissolution leveled off. Fe3+ acted as a chemical oxidant in CuFeS2 leaching and was reduced to Fe2+. Parallel bacterial re-oxidation of Fe2+ contributed to a high Fe3+/Fe2+ ratio and an increase in redox potential. Chemical oxidation of chalcopyrite was slow compared with A. ferrooxidans-initiated solubilization. X-ray analysis revealed new solid phases: (i) jarosite, found in solids from A. ferrooxidans cultures and in chemical controls that initially received Fe2+ or Fe3+, and (ii) S-0, found mostly in iron-amended A. ferrooxidans culture and the corresponding chemical controls. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

A new class of neurotoxin from wasp venom slows inactivation of sodium current

The effects of alpha-pompilidotoxin (alpha-PMTX), a new neurotoxin isolated from the venom of a solitary wasp, were studied on the neuromuscular synapses in lobster walking leg and the rat trigeminal ganglion (TG) neurons. Paired intracellular recordings from the presynaptic axon terminals and the innervating lobster leg muscles revealed that alpha-PMTX induced long bursts of action potentials in the presynaptic axon, which resulted in facilitated excitatory and inhibitory synaptic transmission. The action or alpha-PMTX was distinct from that of other known facilitatory presynaptic toxins, including sea anemone toxins and alpha-scorpion toxins, which modify the fast inactivation of Na+ current. We further characterized the action of alpha-PMTX on Na+ channels by whole-cell recordings from rat trigeminal neurons. We found that alpha-PMTX stowed the Na+ channels inactivation process without changing the peak current-voltage relationship or the activation time course of tetrodotoxin (TTX)-sensitive Na+ currents, and that alpha-PMTX had voltage-dependent effects on the rate of recovery from Na+ current inactivation and deactivating tail currents. The results suggest that alpha-PMTX slows or blocks conformational changes required for fast inactivation of the Na+ channels on the extracellular surface. The simple structure of alpha-PMTX, consisting of 13 amino acids, would be advantageous for understanding the functional architecture of Na+ channel protein.

Effect of cyclosporine on adriamycin induced nephritis

The effects of cyclosporine A (CSA) administration, started as early as renal lesion is induced, on the development of Adriamycin-induced nephropathy were assessed by comparing the time course of this nephropathy in rats receiving CSA with that in non-treated animals (group ADR) over 16 weeks. Throughout the experiment, no significant difference in proteinuria was observed between the groups. At the end of the experiment, there was no significant difference between the groups regarding the frequency of glomerular lesion (Group AADR: Md=23%, P25=15%, P75=75%; Group ADR-CSA: Md=48%, P25=11%, P75=70%); tubulointerstitial lesion index (Group ADR: Md=1.5, P25=1.0, P75=2.5); glomerulosclerosis area (Group ADR = 18.2 +/- 4.2%; Group ADR-CSA = 13.2 +/- 1.4%); and, interstitial fibrosis area (Group ADR+V: 1.75 +/- 0.10%; group ADR-CSA: 1.34 +/- 0.09%). In conclusion, CSA, when, administered since nephropathy induction does not change the course of the disease.

Sufentanil-2-hydroxypropyl-beta-cyclodextrin inclusion complex for pain treatment: Physicochemical, cytotoxicity, and pharmacological evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Archipelago of Fernando de Noronha: An Intriguing Malformed Toad Hotspot in South America

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

LH Response (in vivo and in vitro) to an LHRH Agonist Administered to Domestic Male Cats

We investigated plasma luteinizing hormone (LH) concentration in domestic male cats challenged with Luteinizing Hormone Releasing Hormone Analog (LHRH-A) [des Gly10, (DTrp6)-LHRH ethylamide] that mediates the function of the hypothalamic-piruitary-gonadal axis (HPG). Plasma LH concentrations in cats treated daily with LHRH (10 μg/ 100 μl/kg/day, subcutaneously - sc) for 19 days (LHRH group) and in controls treated with saline (NaCl - 0.9%, same volume - SAL group) were chronically studied. LHRH administration (sc) for 15 days induced a significant fall (P < 0.05) in plasma LH concentrations during the chronic study. After the 15th day of treatment the groups were divided once more into animals treated with LHRH (10 μg/100 μl/kg) or saline (iv), and a time course study (300 min) was performed (acute study). Next, four groups of cats were compared in an acute study involving the sc/iv administration of SAL/SAL, SAL/LHRH, LHRH/SAL, and LHRH/LHRH. The responses of the SAL animals challenged by acute iv administration of LHRH (group SAL/LHRH) were significantly higher (P < 0.01) than those of animals treated with LHRH (sc) (group LHRH/LHRH). LH release was also significantly increased in the latter group (P < 0.05), although the effect was short lasting, being recorded only at the first observation (45 min). An in vitro study with the pituitaries was also performed on day 20. Mean (±SEM) LH concentrations in the culture medium containing pituitaries with LHRH (10-7 M) or saline were determined. In vitro analysis of these pituitaries demonstrated a significantly reduced response (P < 0.05) by animals treated sc with LHRH for 19 days. This study represents a source of data for the domestic cat going beyond its own physiology. Serving as a model, this animal provide important information for the study of reproductive physiology in other members of its family (Felidae), almost all of them threatened with extinction.

Characterization of bornite (Cu5FeS4) electrodes in the presence of the bacterium Acidithiobacillus ferrooxidans

Bornite electrodes were characterized in the absence or in the presence of Acidithiobacillus ferrooxidans, which is an important microorganism involved in metal bioleaching processes. The presence of the bacterium modified the mineral/electrolyte interface, increasing the corrosion rate, as revealed by interferometric, AEM, ICP and EIS analyses. As a consequence of bacterial activity the electrode became porous, increasing its surface heterogeneity. This behavior was correlated with the evolution of impedance diagrams obtained during the time course of experiments. The main difference in these diagrams was the presence of an inductive feature (up to 44 h), which was related to bacterial action on the mineral dissolution, better than to its adhesion on the bornite. The total real impedance measured in presence of the bacterium was about 10 times lower than in its absence, due to the acceleration of the mineral dissolution, because an oxidant environment was maintained.

Changes in norepinephrine and epinephrine concentrations in adrenal gland of the rats submitted to acute immobilization stress

Catecholamines act as neurotransmitters and hormones. Studies conducted to understand the synthesis and metabolism of these monoamines during stress have been the main concern of many authors. This work proposes to investigate the time course of changes in epinephrine and norepinephrine concentration in adrenal gland obtained from rats submitted to acute immobilization stress. The results of the present study indicate that acute immobilization stress during 5 and 15min did not provoke changes in epinephrine and norepinephrine concentrations in adrenal gland in relation to the control group. Such results are justified due to the short time of the stress, showing that the stress did not provoke physiological alteration. The epinephrine and norepinephrine concentrations in adrenal gland increased significantly after the immobilization session in stressed groups during 30 and 50min as compared to control group. This increase probably is due to the emotional component of the immobilization stress. In this way, we suggested that the immobilization stress provoke increase in the biosynthesis of catecholamines in the adrenal gland from rats. However, the results shows that a maximum increase is reached at 30min of immobilization stress and then a decrement of catecholamines levels starts at 50min of the experimental design. This decline in catecholamines level may be consequence of adaptation to stress situations, an increase of the activity of the uptake systems and/or metabolization of catecholamines. In conclusion, these results suggest an effective participation of the adrenal glands to maintain the homeostasis of organism to the stressful conditions. © 2003 Elsevier Ltd. All rights reserved.