Disfunções orofaciais em pacientes infantojuvenis com leucemia aguda / Orofacial dysfunctions in infants and young children with acute leukemia

RESUMO Objetivo Identificar a ocorrência de disfunções orofaciais em pacientes infantojuvenis com leucemia aguda, submetidos à quimioterapia de remissão. Métodos Em um período de 16 meses, 40 pacientes com leucemias agudas, entre 3 e 18 anos de idade, foram admitidos em um hemocentro no estado do Amazonas. Destes, 23 foram incluídos neste estudo transversal e submetidos à avaliação das funções orofaciais, por meio do Nordic Orofacial Test-Screening (NOT-S), entre o trigésimo (D30) e o trigésimo terceiro dia (D33) da fase de indução da remissão. A presença de manifestações orais também foi avaliada por meio de exame clínico. Resultados Disfunção orofacial foi observada em, aproximadamente, metade dos casos avaliados (n=11). Destes pacientes, todos tiveram o domínio Secura de Boca (VI) alterado e 81,8% (n=9) apresentaram alteração no domínio Mastigação e Deglutição (IV). Mucosites em lábios, língua, soalho e orofaringe foram as lesões orais mais encontradas após a fase de indução. Houve associação entre a ocorrência de lesões orais nos pacientes avaliados e a presença de disfunção orofacial, segundo o NOT-S (IC 95%, p-valor = 0,027). Conclusão Sugere-se que a disfunção orofacial seja frequente na fase de indução da remissão em pacientes infantojuvenis com leucemias agudas. Estudos sobre as disfunções orofaciais nessa população, bem como sua relação com as lesões orais são necessários para melhor esclarecimento e compreensão dos impactos funcionais.

ABSTRACT Purpose To Identify the occurrence of orofacial dysfunctions in young children and adolescents with acute leukemia who are undergoing remission chemotherapy. Methods Over a period of 16 months, 40 three to eighteen year -old patients with acute leukemia were admitted to the Amazonas State Hemocenter. Of these, 23 were included in the cross-sectional study and submitted to the evaluation of orofacial functions using the Nordic Orofacial Test-Screening, between D30 and D33 of the remission induction phase. The presence of oral manifestations was also evaluated via clinical examination. Results Orofacial dysfunction was observed in approximately half of the evaluated cases (n=11). Of these patients, all had alterations in the Dryness of the Mouth (VI) domain and 81.8% (n=9) showed alterations in the Chewing and Swallowing (IV) domain. Mucosites on lips, tongue, floor of the mouth and the oropharynx were the most commonly found oral lesions after the remission induction phase. According to the NOT-S, there was an association between the occurrence of oral lesions in the evaluated patients and the presence of orofacial dysfunction (95% CI, p-value = 0.027). Conclusion It is suggested that orofacial dysfunction is frequent in the remission induction phase in children and adolescents with acute leukemia. Studies regarding these orofacial dysfunctions in this population, as well as their relationship with oral lesions, are needed in order to fully understand their functional impact.

Clinical Aspects of the Use of Botulinum Toxin Type A in the Treatment of Dysfunction of the Masticatory System.

The purpose of this work is to present a new, still experimental method of treating temporomandibular disorders (TMD) by injecting botulinum toxin Type A (TBX-A), using its effects not as a toxin but as a medication. The mechanism of TBX-A, indications and contraindications for its use, as well as possible side effects, are discussed. Temporomandibular disorders are of concern to approximately 70-80% of the population. The effect of botulinum toxin depends on blocking the release of acetylcholine from a presynaptic neuromuscular synapse and, in the autonomous system, blocking its release from post-ganglionic cholinergic neurons. In cases of long-term TMJ disorders, muscle activity increases and spastic contractions may even appear. TBX-A offers an opportunity for a normal social and family life for many patients suffering from masticatory system disorders (MSD), who have been isolated from the environment by pain. The study is based on a review of the literature and the authors' own experiences during several attempts to treat patients by this method. TBX-A is a safe medicine when the injection is performed by a well-trained physician.

Involvement of NMDA receptors in the ventrolateral striatum of rats in apomorphine-induced jaw movements.

The role of NMDA receptors in the ventrolateral striatum to modulate dopamine receptor-mediated jaw movements was investigated in freely moving rats, using a magnetic sensor system combined with intracerebral microinjection of drugs. Apomorphine (1mg/kg i.v.) induced repetitive jaw movements that were reduced, in a dose-dependent manner, by bilateral microinjections of the NMDA receptor agonist NMDA (0.1 and 1mug/0.2mul bilaterally) into the ventrolateral striatum. Apomorphine-induced repetitive jaw movements were also reduced, in a dose-dependent manner, by bilateral microinjections of the NMDA receptor antagonists d-APV (0.01 and 0.1mug) or MK-801 (0.5 and 5mug). The inhibitory effect of NMDA (1mug) was reduced by co-administration of MK-801 (0.5mug). Microinjections of drugs into the ventrolateral striatum in the absence of apomorphine did not affect jaw movements. These results suggest that NMDA receptors in the ventrolateral striatum play an important modulatory role in the expression of dopamine receptor-mediated jaw movements. However, similar effects of NMDA and NMDA antagonists echo previous paradoxical findings and indicate that interactions between dopamine and NMDA receptors are complex and multifaceted. Cellular mechanism(s) may involve differential effects of NMDA agonism and antagonism on dopamine D1-like vs D2-like receptors and, possibly, on related GABAergic processes.

Effects of use of anabolic steroids on the masticatory system: a pilot study.

The use of androgenic anabolic steroids (AAS) has increased significantly among athletes in Brazil and other countries. These drugs alter the physiological behavior of bone and muscles, also affecting these structures in masticatory system. This paper aims to evaluate bone and dental changes in users of AAS, as well as the incidence of temporomandibular dysfunction (TMD), compared to athletes not using AAS. Eight athletes were equally divided in two groups, AAS users and non-users. The groups were evaluated using Helkimo index, McNamara cephalometric tracing and cast analysis. The AAS users presented more intense TMD signs and symptoms (Di total value, P = 0.096, Mann-Whitney test), increased cephalometric measures (Co-A, P = 0.020, Mann-Whitney test) and Angle Class II malocclusion, compared to the non-users. These results suggested that the use of AAS alters masticatory structures and increases the incidence of TMD.

The mandible opening response: quantifying aggression elicited by chemical cues in ants.

Social insects have evolved efficient recognition systems guaranteeing social cohesion and protection from enemies. To defend their territories and threaten non-nestmate intruders, ants open their mandibles as a first aggressive display. Albeit chemical cues play a major role in discrimination between nestmates and non-nestmates, classical bioassays based on aggressive behaviour were not particularly effective in disentangling chemical perception and behavioural components of nestmate recognition by means of categorical variables. We therefore developed a novel bioassay that accurately isolates chemical perception from other cues. We studied four ant species: Camponotus herculeanus, C. vagus, Formica rufibarbis and F. cunicularia. Chemical analyses of cuticular extracts of workers of these four species showed that they varied in the number and identity of compounds and that species of the same genus have more similar profiles. The antennae of harnessed ants were touched with a glass rod coated with the cuticular extract of (a) nestmates, (b) non-nestmates of the same species, (c) another species of the same genus and (d) a species of a different genus. The mandible opening response (MOR) was recorded as the aggressive response. In all assayed species, MOR significantly differed among stimuli, being weakest towards nestmate odour and strongest towards odours originating from ants of a different genus. We thus introduce here a new procedure suitable for studying the chemical basis of aggression in ants.

Pharmacology of ionotropic and metabotropic glutamate receptors on neurons involved in feeding behavior in the pond snail, Helisoma trivolvis.

Glutamate is a key regulatory neurotransmitter in the triphasic central pattern generator controlling feeding behavior in the pond snail, Helisoma trivolvis. It excites phase two motor neurons while inhibiting those in phases one and three. However, the receptors that mediate this regulation are only partially characterized. The purpose of these experiments was to further characterize the glutamate receptors on three buccal neurons modulated by glutamate. Intracellular recordings from B5, B19 and B27 neurons were taken during the perfusion of isolated buccal ganglia with agonists that are selective for different vertebrate glutamate receptors. The firing rate of all three neurons was inhibited in a dose-dependent manner by glutamate, including that of B27, a phase 2 motor neuron known to be excited by glutamate in vivo. Quisqualate also reduced the firing rate in all three neurons, and (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD), a relatively non-selective metabotropic glutamate receptor (mGluR) agonist, reduced the firing rate in B5 neurons, but not in B19 or B27 neurons. Agonists selective for vertebrate group I, II and III mGluRs did not affect the firing rate in any of the Helisoma buccal neurons tested, suggesting that mGluR agonist binding sites on these neurons do not closely resemble those on any vertebrate mGluR subtypes. An increase in frequency of action potentials was observed in all three cell types in the presence of 100 micromol l(-1) kainate (KA), suggesting the presence of excitatory (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/KA-like receptors. However, electrotonic coupling between B19 and B27 neurons, and a lack of effect of KA on isolated B19 neurons suggest the excitatory effects of KA on this neuron are indirect. These findings suggest the presence of multiple glutamate receptor subtypes in molluscan neurons that do not always resemble vertebrate receptors pharmacologically.

Long-term exposure to histamine induces the expression of an embryonic-like motor pattern in an adult nervous system.

Neuromodulatory inputs play important roles in shaping the outputs of neural networks. While the actions of neuromodulatory substances over the short term (seconds, minutes) have been examined in detail, far less is known about the possible longer-term (hours) effects of these substances. To investigate this issue, we used the stomatogastric nervous system (STNS) of the lobster to examine the short- and long-term effects of histamine on rhythmic network activity. The application of histamine to the entire STNS had strong inhibitory effects on all three of the STNS networks, observable within minutes. In contrast, longer-term (> 1 h) application of histamine induced the expression of a single, unified rhythm involving neurons from all three networks. Selective application of histamine to different regions of the STNS demonstrated that a unified rhythm arises following the long-term application of histamine to the commissural ganglia (CoGs; modulatory centres), but not the stomatogastric ganglion (site of neural networks). Strikingly, the single rhythm observed following the long-term application of histamine to the CoGs exhibits many similarities with the single rhythm expressed by the embryonic STNS. Together, these results demonstrate that histamine has markedly different short- and long-term effects on network activity; short-term effects arising through direct actions on the networks and long-term effects mediated by actions on modulatory neurons. Furthermore, they indicate that histamine is able to induce the expression of an embryonic-like rhythm in an adult system, suggesting that long-term actions of histamine may play key roles in the development of the STNS networks.