Influence of laser photobiomodulation (GaAlAs) on salivary flow rate and histomorphometry of the submandibular glands of hypothyroid rats.

The aim of this study was to analyze the influence of laser photobiomodulation in salivary flow, weight, and histomorphometry of the submandibular glands of hypothyroid rats. Fifty-six male Wistar albino rats were divided in euthyroid group and hypothyroid group, treated with propylthiouracil (PTU) to induce hypothyroidism. Each group was divided into control (without laser) and laser groups (GaAlAs): λ660 nm (40 mW), λ780 nm (40 mW), and λ780 nm (70 mW). The laser application on the submandibular gland occurred after 2 weeks of PTU treatment and repeatedly during 2 weeks every 48 h. The rats were anesthetized, tracheostomized, and the evaluation of the salivary flow rate (µL/min/100 g body weight) was made by the weight of the saliva collected for 15 min from the first drop. After the animals' death, the glands were dissected and processed for histological analysis. There was an evident reduction of the salivary flow of hypothyroid rats in all groups in comparison to euthyroid group (Mann-Whitney test, p < 0.05). No significant difference was found in the salivary flow of rats that received laser photobiomodulation compared with their control groups. Histological analysis revealed a decrease in the parenchyma of the salivary glands of hypothyroid rats, but the laser was not able to reverse this process. Hypothyroid rats irradiated or not with laser showed acini and acinar cells with significantly smaller areas than euthyroid groups. The laser photobiomodulation protocol used was not able to change salivary flow or reverse the acinar atrophy process in the submandibular glands of hypothyroid rats.

Effects of LED phototherapy on relative wound contraction and reepithelialization during tissue repair in hypothyroid rats: morphometric and histological study.

The aim of this study was to assess morphometrically and histologically, the effects of light-emitting diode (LED) (λ630 ± 20 nm) phototherapy on reepithelialization and wound contraction during tissue repair in hypothyroid rats. Thyroid hormone deficiency has been associated with disorders of tissue repair. LED phototherapy has been studied using several healing models, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. Under general anesthesia, a standard surgical wound (1 cm(2)) was produced on the dorsum of 48 male Wistar rats divided into four groups of 12 animals each: EC-control euthyroid, ED-euthyroid + LED, HC-control hypothyroid, and HD-Hypothyroid + LED. The irradiation started immediately after surgery and was repeated every other day for 7 and 14 days. Photographs of the wound were taken at the day of the surgical procedure and on days 8 and 15 after surgery, when animals' deaths occurred. The specimens were removed, routinely processed, and stained with hematoxylin/eosin. Seven days after the surgery, it was possible to observe statistically significant reductions in the wound area of the irradiated euthyroid group, in comparison to hypothyroid group, irradiated and non-irradiated (ANOVA, p < 0.05). The reepithelialization was significantly higher in the euthyroid and hypothyroid groups irradiated with LED than in the non-irradiated groups (Fisher's test, p < 0.05). No significant difference was found in the experimental period of 14 days among the groups. The hypothyroidism delayed wound healing and the LED phototherapy, at these specific parameters, improved the process of reepithelialization in the presence of hypothyroidism.

Headache after evaluation with transcranial magnetic stimulation in a healthy participant. Case report / Cefaleia após avaliação com estimulação magnética transcraniana em participante saudável. Relato de caso

ABSTRACT BACKGROUND AND OBJECTIVES: Adverse effects during noninvasive stimulation of the brain are rare events. The objective of this study is to present a patient´s case with an intense headache with autonomic signs after single-pulse transcranial magnetic stimulation. CASE REPORT: A 28-year old female patient, volunteered to participate in a study on the evaluation of motor cortical excitability after the injection of lidocaine in the first dorsal interosseous muscle. The resting motor threshold was estimated at four moments: before the procedure, immediately after the procedure, 30 minutes, and one hour after the procedure. At the end of the experiment, 240 pulses were performed. The participant reported mild-intensity headache that rapidly progressed to severe, left hemicranial headache, the same region where the transcranial magnetic stimulation pulses were applied. In association with the pain, she had nausea, vomiting, photophobia, conjunctival hyperemia, lacrimation, and ipsilateral eyelid edema, requiring emergency care. CONCLUSION: It is possible that supraliminal intensities (>100% of resting motor threshold) in single-pulse transcranial magnetic stimulation may predispose to adverse effects. Other factors such as skull anatomy, electrical impedance, age, gender, cognitive and affective status, use of medications, hormone levels, the concentration of neurotransmitters and receptor expression, genetic factors and the circadian cycle may also be involved. There are no well-established safety models to guide assessment protocols with single-pulse transcranial magnetic stimulation, considered a technique with a low incidence of adverse effects and with little demand for safety studies.

RESUMO JUSTIFICATIVA E OBJETIVOS: Efeitos adversos durante a estimulação não invasiva do cérebro são eventos considerados raros. O objetivo deste estudo foi apresentar um caso de paciente com cefaleia intensa com sinais autonômicos após estimulação magnética transcraniana de pulso único. RELATO DO CASO: Paciente do sexo feminino, 28 anos, saudável, voluntariamente se apresentou para participar de pesquisa sobre avaliação de excitabilidade cortical motora após a realização de injeção de lidocaína no músculo primeiro interósseo dorsal. O limiar motor em repouso foi estimado em quatro momentos: antes do procedimento, imediatamente após o procedimento, 30 minutos e uma hora após o procedimento. Foram realizados ao final do experimento 240 pulsos. A participante referiu cefaleia, de leve intensidade, que rapidamente progrediu para cefaleia intensa, hemicraniana à esquerda, na região onde os pulsos da estimulação magnética transcraniana foram aplicados. Em associação à dor, apresentou náuseas, vômitos, fotofobia, hiperemia conjuntival, lacrimejamento e edema palpebral ipsilaterais, com necessidade de atendimento em unidade de emergência. CONCLUSÃO: É possível que intensidades supralimiares (>100% do limiar motor em repouso) em estimulação magnética transcraniana de pulso único possam predispor a efeitos adversos. Outros fatores como anatomia do crânio, impedância elétrica, idade, sexo, estado cognitivo e afetivo, uso de fármacos, níveis hormonais, concentração de neurotransmissores e expressão de receptores, fatores genéticos e ciclo circadiano também podem ser implicados. Não há modelos de segurança bem estabelecidos para guiar protocolos de avaliação com estimulação magnética transcraniana de pulso único, considerada uma técnica com baixa incidência de efeitos adversos e com baixa demanda de atenção de estudos sobre segurança.

Effect of laser phototherapy (λ660 nm) on type I and III collagen expression during wound healing in hypothyroid rats: an immunohistochemical study in a rodent model.

OBJECTIVE: The aim of this study was to assess, immunohistochemically, the impact of hypothyroidism and the effect of laser phototherapy on the expression of type I and III collagen during wound healing. BACKGROUND DATA: Hypothyroidism has been associated with the disruption of the body's metabolism, including the healing process. Laser phototherapy has been shown to be effective in improving wound healing, but its usefulness on enhancing wound healing under hypothyroid condition remains unknown. MATERIALS AND METHODS: Using general anesthesia, a standard surgical wound (1 cm(2)) was created on the dorsa of 48 Wistar rats divided into four groups of 12 animals each: control euthyroid (EC), euthyroid plus laser (EL), control hypothyroid (HC), and hypothyroid plus laser (HL). The irradiation with laser GaAlAs [λ660 nm, 40 mW, 1 W/cm(2), continuous wave (CW), ø=0.04 cm(2)] started immediately after surgery and was repeated every other day until end-point of study was reached, and animals were euthanized (i.e., 7 and 14 days). Laser light was applied on four different points (6 J, 150 sec and 150 J/cm(2) per point). Hypothyroidism was induced in rats with propylthiouracil (0.05 g/100 mL) administered orally for 4 weeks and maintained until the end of the experiment. Immunohistochemistry for collagen I and III was performed with EnVision(™) in the specimens removed. RESULTS: Seven days after the surgery EC, EL, and HL groups showed higher immunoexpression of collagen I and lower immunoexpression of collagen III in the newly formed tissue. There was increased immunoexpression of collagen I in EC when compared with HC (p=0.019). The immunoexpression of collagen III was significantly lower in EL than in EC (p=0.047) and HL (p=0.019). No significant difference was found in the experimental period of 14 days among the groups. CONCLUSIONS: Laser light therapy performed with the parameters of this investigation increased immunoexpression of collagen type I during tissue repair, and improved the quality of newly formed tissue in the presence of hypothyroidism.

Participation of nitric oxide synthase and cyclooxygenase-2 in the salivary secretion of hypothyroid endotoxemic rats / Participação da sintase do óxido nítrico e da ciclooxigenase-2 na secreção salivar de ratos hipotireoidianos endotoxêmicos

Purpose: In the present study the participation of nitric oxide synthase (NOS) and cyclooxygenase-2 (COX-2) on salivary secretion in endotoxemic hypothyroid rats was investigated. Methods: Male Wistar rats with an initial weight of 180 g were distributed into two groups, normal (N) or treated with propylthiouracil, 0.05 g/100 mL, administered orally for 5 weeks to induce hypothyroidism. Both groups were treated with lypopolysaccharide (LPS) (2.5 mg/kg; i.p.) to induce endotoxemia, or saline solution (SL), 90 min before salivary stimulation with pilocarpine (5 mg/kg; i.p.). Normal and PTU rats were divided into two groups each (n=07/09), receiving either L-NAME (10 mg/kg; i.p.), NOS inhibitor, or meloxicam (MLX) (0.5 mg/kg; i.p.), preferential COX-2 inhibitor, 30 min before endotoxemia challenge. Saliva was collected over a 15 min period (µL/min/100 g body wt.) from the time of the first drop of saliva. Results: Hypothyroidism decreased salivary flow rate in both groups of rats (LPS and SL). Endotoxemia and NOS inhibition by L-NAME reduced salivary flow in N rats. Meloxicam stimulated salivary secretion in the physiological state and systemic inflammation, induced by LPS, in N and PTU rats (Mann-Whitney Test; P < 0.05). Conclusion: In hypothyroid endotoxemic rats, it is COX-2 that modulates salivary secretion, not NOS.

Objetivo: Investigou-se a participação da sintase do óxido nítrico (NOS) e da ciclooxigenase-2 (COX-2) na secreção salivar de ratos hipotireoidianos endotoxêmicos. Metodologia: Ratos Wistar com peso inicial de 180 g foram distribuídos em dois grupos, normais (N) ou tratados com propiltiouracil (PTU) 0,05 g/100 mL, via oral, durante 5 semanas, para induzir hipotireoidismo. Ambos os grupos foram tratados com lipopolissacarídeo (LPS), 2,5 mg/kg i.p., para indução de endotoxemia ou salina (SL), 90 min antes da estimulação salivar com pilocarpina (5 mg/kg; i.p.). Os ratos N e PTU foram divididos em dois grupos cada (n = 07/09) e receberam injeções de L-NAME (10 mg/kg; i.p.), inibidor da NOS, ou meloxicam (MLX) (0,5 mg/kg;i.p.), inibidor preferencial da COX-2, 30 min antes da indução da endotoxemia. O fluxo salivar (µl/min/100 g de p.c.) foi avaliado durante um período de 15 min a partir da primeira gota de saliva. Resultados: O hipotireoidismo diminuiu o fluxo salivar em ratos tratados ou não com LPS. A endotoxemia e a inibição da NOS, através do L-NAME reduziu o fluxo salivar em ratos N. O MLX estimulou a salivação em situações fisiológicas e inflamatórias nos ratos N e PTU (Mann-Whitney; P < 0,05). Conclusão: A COX-2, mas não a NOS, modula a secreção salivar em ratos hipotireoidianos endotoxêmicos.

Participation of nitric oxide synthase and cyclooxygenase-2 in the salivary secretion of hypothyroid endotoxemic rats / Participação da sintase do óxido nítrico e da ciclooxigenase-2 na secreção salivar de ratos hipotireoidianos endotoxêmicos

Purpose: In the present study the participation of nitric oxide synthase (NOS) and cyclooxygenase-2 (COX-2) on salivary secretion in endotoxemic hypothyroid rats was investigated. Methods: Male Wistar rats with an initial weight of 180 g were distributed into two groups, normal (N) or treated with propylthiouracil, 0.05 g/100 mL, administered orally for 5 weeks to induce hypothyroidism. Both groups were treated with lypopolysaccharide (LPS) (2.5 mg/kg; i.p.) to induce endotoxemia, or saline solution (SL), 90 min before salivary stimulation with pilocarpine (5 mg/kg; i.p.). Normal and PTU rats were divided into two groups each (n=07/09), receiving either L-NAME (10 mg/kg; i.p.), NOS inhibitor, or meloxicam (MLX) (0.5 mg/kg; i.p.), preferential COX-2 inhibitor, 30 min before endotoxemia challenge. Saliva was collected over a 15 min period (µL/min/100 g body wt.) from the time of the first drop of saliva. Results: Hypothyroidism decreased salivary flow rate in both groups of rats (LPS and SL). Endotoxemia and NOS inhibition by L-NAME reduced salivary flow in N rats. Meloxicam stimulated salivary secretion in the physiological state and systemic inflammation, induced by LPS, in N and PTU rats (Mann-Whitney Test; P < 0.05). Conclusion: In hypothyroid endotoxemic rats, it is COX-2 that modulates salivary secretion, not NOS.

Objetivo: Investigou-se a participação da sintase do óxido nítrico (NOS) e da ciclooxigenase-2 (COX-2) na secreção salivar de ratos hipotireoidianos endotoxêmicos. Metodologia: Ratos Wistar com peso inicial de 180 g foram distribuídos em dois grupos, normais (N) ou tratados com propiltiouracil (PTU) 0,05 g/100 mL, via oral, durante 5 semanas, para induzir hipotireoidismo. Ambos os grupos foram tratados com lipopolissacarídeo (LPS), 2,5 mg/kg i.p., para indução de endotoxemia ou salina (SL), 90 min antes da estimulação salivar com pilocarpina (5 mg/kg; i.p.). Os ratos N e PTU foram divididos em dois grupos cada (n = 07/09) e receberam injeções de L-NAME (10 mg/kg; i.p.), inibidor da NOS, ou meloxicam (MLX) (0,5 mg/kg;i.p.), inibidor preferencial da COX-2, 30 min antes da indução da endotoxemia. O fluxo salivar (µl/min/100 g de p.c.) foi avaliado durante um período de 15 min a partir da primeira gota de saliva. Resultados: O hipotireoidismo diminuiu o fluxo salivar em ratos tratados ou não com LPS. A endotoxemia e a inibição da NOS, através do L-NAME reduziu o fluxo salivar em ratos N. O MLX estimulou a salivação em situações fisiológicas e inflamatórias nos ratos N e PTU (Mann-Whitney; P < 0,05). Conclusão: A COX-2, mas não a NOS, modula a secreção salivar em ratos hipotireoidianos endotoxêmicos.

Hipotireoidismo altera secreção e composição salivar em ratos sépticos / Hypothyroidism alters salivary secretion and composition in septic rats

Objetivo: Este estudo investigou os efeitos do hipotireoidismo na secreção salivar total, nas concentrações de proteína e de eletrólitos (Na+, K+ e Ca+2) da saliva estimulada de ratos sépticos. Metodologia: Foram utilizados ratos Wistar (200-280g) separados em dois grupos: tireoidectomizados (TX) e controle (N). Os ratos receberam injeção intraperitoneal de lipopolissacarídeo (LPS), 250 μg/100g de peso corporal (p.c.), ou salina (SL), 90 min antes da estimulação salivar com pilocarpina (5mg/kg de p.c.) para coleta de fluxo salivar total por 15 min (μL/min/100g de p.c.). A concentração de proteínas totais foi analisada pelo método de Lorwy e as concentrações de eletrólitos através de reagente padrão (Doles) para fotômetro de chama (Na+, K+) e teste colorimétrico (Ca+2). Resultados: O hipotireoidismo e a endotoxemia induzida pelo LPS diminuíram o fluxo salivar (Teste de Mann-Whitney, P < 0,05). A sepse reduziu significativamente a concentração de proteínas totais salivar de ratos TX e a concentração de íon sódio na saliva de ratos N. Não houve alteração nas concentrações de íon potássio em nenhum dos grupos, mas o hipotireoidismo provocou aumento da concentração de íon cálcio na saliva. Conclusão: A secreção salivar e a composição da saliva são alteradas pelo hipotireoidismo em ratos sépticos.

Purpose: We investigated the effects of hypothyroidism on salivary flow rate, total protein and electrolytes concentrations (Na+, K+ and Ca+2) in septic rats. Methods: Male Wistar rats (200-280g) were thyroidectomized (TX) or sham operated (N) and treated with lypopolysaccharide (LPS) (250 μg/100g b.w.; i.p.) or saline (SL), 90 min before salivary stimulation with pilocarpine (5mg/kg; i.p.). Saliva was collected over 15 min (μL/min/100g of b.w.). Total proteins were analyzed by Lorwy method and electrolytes concentrations were determined by flame fotometry (Na+, K+) and colorimetric test (Ca+2).Results: Hypothyroidism and sepsis by LPS injection caused a decrease in salivary flow rates (Mann-Whitney Test, P < 0.05). LPS injection decreased salivary total protein concentration in TX rats and sodium concentration in N rats. Sepsis and thyroid hormones do not participate in the molecular mechanism of potassium transport, but hypothyroidism increased calcium concentration in saliva. Conclusion: Salivary flow rate and composition are modified by hypothyroidism in rats with sepsis.

Influência da proporçäo pó: líquido nas propriedades biológicas de cimento endodôntico à base de óxido de zinco e eugenol / Biological properties of a zinc oxide-eugenol endodontic sealer related to is powder: liquid ratio

O comportamento do tecido conjuntivo subcutâneo ao implante de tubos de polietileno contendo proporçöes variadas de um cimento endodôntico à base de óxido de zinco e eugenol foi avaliado a fim de verificar a relaçäo entre as características da reaçäo inflamatória tecidual e a proporçäo de eugenol empregada. Foi demonstrado que a técnica do implante de tubos de polietileno é viável para o estudo preliminar da biocompatibilidade de materiais odontológicos. O cimento analisado mostrou-se irritante em todas as proporçöes empregadas, porém houve evidências da capacidade de reparo tecidual, a longo prazo. A intensidade da resposta inflamatória tecidual foi diretamente proporcional à quantidade de eugenol. Aos 60 dias, o grupo experimental com menor quantidade de eugenol apresentou a menor intensidade de resposta inflamatória dentre todos grupos experimentais ( Mann Whitney p < 0,001). Concluiu-se que o eugenol é diretamente responsável por, no mínimo, parte da citoxicidade dos cimentos endodônticos à sua base