Leishmania spp. in Didelphis albiventris and Micoureus paraguayanus (Didelphimorphia: Didelphidae) of Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potential role for dog fleas in the cycle of Leishmania spp.

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

Astrocytes and human cognition: Modeling information integration and modulation of neuronal activity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes

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

Ligand Exchange Inducing Efficient Incorporation of CisPt Derivatives into Ureasil-PPO Hybrid and Their Interactions with the Multifunctional Hybrid Network

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Enhanced ERbeta immunoexpression and apoptosis in the germ cells of cimetidine-treated rats

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

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 1)

The participation of the trapezius (pars media) and rhomboideus major muscles in free movements of abduction, adduction, flexion, extension and hyperextension of the arm was studied electromyographically. These muscles were active and synergic in all analysed movements, both acting with intensity that ranged from moderate to very marked.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 2)

The participation of the trapezius (pars media) and rhomboideus major muscles were studied electromyographically in movements of lateral and medial rotation (free and against resistance) of the arm. In the majority of cases both muscles were inactive during the performance of the analysed movements. Cases in which only one or both muscles acted in free rotation occurred only at the second half or ending of the movement. Records of electrical potentials during against resistance rotation were due to tensional efforts at the shoulder level.

Effect of cholinergic and adrenergic stimulation of the subfornical organ on water intake

Cholinergic and adrenergic agonists and antagonists were injected directly into the subfornical organ (SFO), via implanted cannulae, and the volume of water ingested was recorded over a period of 1 hour after injection. Application of 2 nmol carbachol caused intense water intake in 100% of the animals (8.78±0.61 ml), with a very short intake latency. When the 2 nmol carbachol dose was preceded by increased doses of atropine, a progressive reduction in water intake was observed, with complete blockage of the thirst-inducing response to carbachol at the 20 nmol dose level with atropine. Followed by several doses of hexamethonium, the water intake caused by application of 2 nmol carbachol was reduced, although the response was not totally blocked. Injection of 80 nmol of nicotine had a significant thirst-inducing inducing effect in 50% of the animals studied (1.06±0.18 ml) and increase in water intake was further reduced by application of increased doses of hexamethonium. Raising the dose levels of noradrenaline into th SFO caused an increase in water intake although to a lesser degree than was observed after carbachol injection. When the 40 nmol dose of noradrenaline was preceded by increased doses of propranolol (5 to 40 nmol), there was a gradual reduction in water intake, with total blockage at the 40 nmol dose. Application of phentolamine in doses of 10 to 80 nmol caused no reduction in water intake after 40 nmol of noradrenaline. Application of isoproterenol at doses from 20 to 160 nmol into the SFO caused a dosedependent increase in water intake which was blocked by previous applications of propranolol. These results support the hypothesis that the water intake caused by chemical stimulation of the SFO is mainly due to muscarinic cholinergic receptors, although the influence of nicotinic receptors or participation of adrenergic mediation should not be ruled out. © 1984.

Changes in sensitivity of the isolated guinea-pig vas deferens induced by a lyophilized Phoradendron latifolium leaf infusion

The effect of a lyophilized mistletoe infusion (LMI) was studied on isolated guinea-pig vas deferens. LMI caused a contraction which was partially blocked by phentolamine but not by atropine. LMI caused a shift to the left of the norepinephrine concentration-effect curve (CEC), an effect which appeared to be blocked by atropine and was absent in animals previously treated with reserpine and α-methyl-para-tyrosine. The increase of the norepinephrine maximal response induced by LMI was not blocked by atropine or pharmacological denervation. LMI caused a shift to the right of the acetylcholine CEC and had no effect on the acetylcholine maximal response. These results suggest that the effects seem to be due mainly to the presence of potassium ion in the LMI; however, the participation of muscarinic agonist(s) of reduced intrinsic activity or some tyramine-like substance could not be ruled out.

Effect of adrenergic stimulation of the amygdaloid complex on water intake

The effect of noradrenaline, isoproterenol, phentolamine and propranolol, injected into the basolateral nuclei of the amygdala on water intake, was investigated in male Holtzman rats. The injection of noradrenaline (40 nmol) into the amygdaloid complex (AC) of satiated rats produced no change in water intake (0.05 ± 0.03 ml/1 hour). The injection of isoproterenol (40 nmol) produced an increase in water intake in sedated rats (1.93 ± 0.23 ml/1 hour). Noradrenaline injected into the AC produced a decrease in water intake in deprived rats (0.40 ± 0.19 ml/1 hour). The injection of isoproterenol into the AC of deprived rats produced no change in water intake in comparison with control (11.65 ± 1.02 and 10.92 ± 0.88 ml/1 hour, respectively). When compared with control values, phentolamine injected prior to noradrenaline blocked the inhibitory effect of noradrenaline on water intake in deprived rats (10.40 ± 1.31 ml/1 hour). Propranolol blocked the effect of isoproterenol in satiated rats (0.85 ± 0.49 ml/1 hour) and also blocked the water intake induced by deprivation (0.53 ± 0.38 ml/1 hour). In satiated and deprived animals the injection of phentolamine before hexamethonium blocked the inhibitory effect of hexamethonium on water intake. In satiated animals, when hexamethonium was injected alone, water intake was 0.39 ± 0.25 ml/1 hour and when hexamethonium was injected with phentolamine, water intake was 1.04 ± 0.3 ml/1 hour. In deprived animals, hexamethonium alone blocked water intake (0.40 ± 0.17 ml/1 hour) and when injected with phentolamine it elicited an intake of 9.7 ± 1.8 ml/1 hour. these results clearly demonstrate the participation of catecholaminergic receptors of the AC in the regulation of water intake.

Characterization of the antinociceptive and sedative effect of amitraz in horses

Amitraz, an acaricide used to control ectoparasites in animals has a complex pharmacological activity, including α2-adrenergic agonist action. The purpose of this research was to investigate the possible antinociceptive and/or sedative effect of amitraz in horses. The sedative effect of the intravenous (i.v.) injection of dimethylformamide (DMF, 5 mL, control) or amitraz (0.05, 0.10, 0.15 mg/kg), was investigated on the head ptosis test. The participation of α2-adrenergic receptors in the sedative effect provoked by amitraz was studied by dosing yohimbine (0.12 mg/kg, i.v.). To measure the antinociception, xylazine hydrochloride (1 mg/kg, i.v., positive control) and the same doses of amitraz and DMF were used. A focused radiant light/heat directed onto the fetlock and withers of a horse were used as a noxious stimulus to measure the hoof withdrawal reflex latency (HWRL) and the skin twitch reflex latency (STRL). The three doses of amitraz used (0.05, 0.10 and 0.15 mg/kg) provoked a dose-dependent relaxation of the cervical muscles. The experiments with amitraz and xylazine on the HWRL showed that after i.v. administration of all doses of amitraz there was a significant increase of HWRL up to 150 min after the injections. Additionally, there was a significant difference between control (DMF) and positive control (xylazine) values up to 30 min after drug injection. On the other hand, the experiments on the STRL show that after administration of amitraz at the dose of 0.15 mg/kg, a significant increase in STRL was observed when compared with the control group. This effect lasted up to 120 min after injection. However, no significant antinociceptive effect was observed with the 0.05 and 0.10 mg/kg doses of amitraz or at the 1.0 mg/kg dose of xylazine.

Apoptosis in the early developing periodontium of rat molars

Development of the periodontium involves a series of complex steps that result in the formation of root dentine, cementum, bone and fibres of the ligament. These precisely controlled and timed events require the participation of the enamel organ derived epithelial cells of Hertwig's (HRS) and ectomesenchymal cells of the dental follicle. These events involve rapid turnover of the tissues and cells, including disappearance of epithelial cells of HRS. Thus, it seemed likely to us that programmed cell death (apoptosis) may play a role in the development of the periodontium. Fragments of first molars, obtained from 14- and 29-day-old rats, were fixed in glutaraldehyde-formaldehyde and processed for light and electron microscopy. For the TUNEL method for detection of apoptosis, specimens were fixed in 4% formaldehyde and embedded in paraffin. Results confirmed that epithelial cells of HRS maintain a close relationship with the forming dentine root, and that they may become trapped in the dentino-cemental junction. Some of the epithelial cells exhibited ultrastructural features which are consistent with the interpretation that they were undergoing programmed cell death, i.e. apoptosis. Periodontal fibroblast-like cells showed typical images of apoptosis and engulfed apoptotic bodies. TUNEL positive structures were present in all corresponding regions. It seems therefore that apoptosis of epithelial cells of HRS and fibroblast-like cells of the periodontal ligament constitutes an integral part of the developmental process of the tissues of the periodontium. (C) 2000 Wiley-Liss, Inc.

Intrauterine dentistry: an integrated model of prevention.

Intrauterine Dentistry is a highly relevant subject of our time. The use of preventive measures in the intrauterine stage can avoid several diseases, among these, dental caries. The WHO advises that from the 4th month of pregnancy, women should avoid the intake of sugar, so that the fetus, future child, does not develop an exaggerated attraction for these types of foods, thus being susceptible to caries. Through questionnaires sent to gynecologist-obstetricians and dentists, this research investigated the information they have about this subject and how they instruct their patients. Questionnaires were also sent to pregnant women requesting information about the instructions they had received for the prevention of oral diseases of their fetus. Seventy-one percent of the dentists and 80% of the gynecologist-obstetricians reported having instructed the pregnant women to reduce the intake of sugar. However, only 13.6% of the dentists and no gynecologist-obstetrician instructed the reduction of sugar intake between the 12th and 18th week of pregnancy. A total of 42.2% of the pregnant women referred to these instructions, but none received instruction as to the specific period of the 12th and 18th week. An ideal model of treatment for pregnant women must include integrated and multiprofessional treatment, in which general dentists and gynecologist-obstetricians work together with the participation of the patient.

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.