Evaluation of subchronic formaldehyde exposure in rats with open field test / Evaluación de la exposición al formaldehído subcrónico en ratas con prueba de campo abierto

SUMMARY: Formaldehyde (FA), which is an indispensable chemical substance in anatomy and pathology, is a very harmful substance for living things. In our study, the purpose was to investigate the changes in behavior of rats exposed to subchronic formaldehyde with open field test. We divided 24 Wistar-Albino rats into 3 groups. The first group (n=8) was identified as the control group, and normal air breathing was ensured. Low-dose FA (mean 1 ppm) was inhaled in the second group, and high-dose FA (mean 10 ppm) was inhaled in the third group. FA exposure was done for 4 hours, 12 weeks, and 5 days a week. The rats were subjected to open field test during the first week and the last week of FA exposure. We observed significant decreases in the number of vertical movements and grooming in rats in the experimental group compared to the control group in the open field test (p 0.05). As a conclusion, we can argue that FA causes changes in the behaviors of rats regardless of dose and duration.

RESUMEN: El formaldehído (FA), una sustancia química indispensable en la anatomía y patología, pero es un elemento sumamente nocivo para todos los seres vivos., El objetivo de nuestro estudio fue investigar los cambios en el comportamiento de ratas expuestas a formaldehído subcrónico con prueba de campo abierto. Utilizamos 24 ratas Wistar-Albino divididas en 3 grupos. El primer grupo (n = 8) se identificó como el grupo de control y se aseguró una respiración normal de aire. En el segundo grupo se inhalaron dosis bajas de FA (media de 1 ppm) y en el tercer grupo se inhalaron dosis altas de FA (media de 10 ppm). La exposición a FA se realizó durante 4 horas, 12 semanas y 5 días a la semana. Las ratas fueron sometidas a una prueba de campo abierto durante la primera semana y la última semana de exposición a FA. Observamos disminuciones significativas en el número de movimientos verticales y acicalamiento en ratas en el grupo experimental en comparación con el grupo control en la prueba de campo abierto (p 0,05). Como conclusión, podemos argumentar que la AF provoca cambios en el comportamiento de las ratas independientemente de la dosis y la duración.

Análise da presença de formol e avaliação do ph de alisantes capilares / Analysis of presence of formol and ph assessment in hair straighteners

O processo de alisamento capilar é uma prática comum realizada nos salões de beleza. O procedimento exige a utilização de substâncias com capacidade de rompimento das cadeias dissulfídricas da fibra capilar com posterior modelamento para o efeito desejado, sendo o formol um dos compostos mais utilizados para esta finalidade, porém indevidamente. De acordo com a legislação vigente, o formol só pode ser utilizado em produtos cosméticos com a função de conservante em uma concentração máxima de 0,2%. Devido a seu uso incorreto em produtos capilares o presente trabalho teve como objetivo realizar uma análise semi-quantitativa da presença de formol em amostras de alisantes capilares, bem como verificar o pH destes produtos. Foram obtidas 22 amostras de alisantes capilares doadas por salões de beleza da região de Umuarama - PR. A determinação da presença de formol foi realizada através da reação de Shiff e comparação com escala colorimétrica de concentrações padronizadas de formaldeído variando de 0,005% a 10%. A verificação do pH foi realizada através da preparação de soluções aquosas de 10% do alisante e posterior aferição em pHmetro digital. Das amostras analisadas, verificou-se 22,72% encontraram-se em conformidade, apresentando quantidade de formaldeído adequada com a legislação (até 0,2%) ou ausência do composto, enquanto que 77,28% apresentaram valores acima do permitido. Já o pH adequado foi constatado em apenas 13,64% amostras. O uso incorreto ou exagerado do formol pode acarretar danos à saúde, como cefaléia, dispnéia, queimadura, edema pulmonar e até câncer. Uma maior fiscalização deve ser realizada nos estabelecimentos que realizam procedimentos de alisamento capilar, bem como nas indústrias produtoras e ainda em importadoras, para uma melhor garantia do cumprimento da legislação tanto para a preservação da saúde dos profissionais quando dos usuários.

The hair-straightening process is a common practice in most beauty salons. The procedure requires the use of substances capable of disrupting the disulfide chains of the hair fiber with subsequent modeling for the desired effect, with formaldehyde being one of the most commonly but improperly used compounds for this purpose. According to the current legislation, formaldehyde can only be used in cosmetic products as a preservative function in a maximum concentration of 0.2%. Due to its incorrect use in capillary products, this work has the purpose of developing a semi-quantitative analysis of the presence of formaldehyde in samples of hair straighteners, as well as verifying the pH of those products. Twenty-two samples of hair straighteners were donated by beauty salons from the region of Umuarama-PR. The determination of the presence of formaldehyde was performed using the Shiff reaction and compared using the colorimetric scale for standard formaldehyde concentrations varying from 0.005% to 10%. The pH verification was carried out by the preparation of 10% aqueous solutions of the straightener and subsequent measurement in a digital pH meter. From the analyzed samples, 22.72% were found to be in compliance, presenting the amount of formaldehyde within the legislation (up to 0.2%) or absence of the compound, while 77.28% presenting values above the legal limitations. Additionally, adequate pH was verified in only 13.64% of the samples. Incorrect or exaggerated use of formaldehyde can lead to health issues, such as headache, dyspnea, burns, pulmonary edema and even cancer. Greater surveillance should be carried out in establishments that perform hair straightening procedures as well as in the producing and importing industries in order to guarantee better compliance with the legislation both for the preservation of the health of professionals and users alike.

La inflamación inducida por formalina favorece el desarrollo del melanoma B16 en ratones Balb/C / inflamation induced by formaline promotes the development of melanoma B16 in Balb/C mice

El cáncer es la segunda causa de muerte en el mundo representando el melanoma 1% de todos los tipos de cáncer. Se ha planteado que el cáncer es una enfermedad inflamatoria sistémica que genera radicales libres causando mutaciones y liberan factores tróficos que favorecen la iniciación tumoral y la proliferación celular, respectivamente. Con el objetivo de estudiar el efecto de la inflamación inducida por formalina sobre el desarrollo del melanoma B16, 22 ratones Balb/C fueron distribuidos en tres grupos: Control Melanoma, Melanoma-Formalina y Control Formalina. A los grupos CF y MF se les aplicó 20 µl de Formalina al 2% en el dorso de la pata trasera derecha a nivel subcutáneo; a los grupos CM y MF se le trasplantaron 100.000 células melanocíticas vía subcutánea en la superficie plantar de la pata derecha, 24 horas posteriores a la formalina. Los ratones del grupo CF desarrollaron una inflamación que fue máxima entre la primera y segunda semana y luego cedió progresivamente hasta desaparecer a la sexta semana. Los ratones del grupo CM desarrollaron máculas tumorales hasta 30 mm² que involucionaron espontáneamente. Los ratones del grupo MF desarrollaron masas tumorales que alcanzaron hasta 300 mm³ entre la 3-4 semanas post-trasplante y luego disminuyeron progresivamente de volumen. Los ratones de los grupos CF y MF disminuyeron significativamente de peso respecto al grupo CM. En conclusión, la inflamación inducida por formalina favorece el desarrollo tumoral en un modelo alogénico de melanoma maligno.

Cancer is the second cause of death around the world, representing melanoma 1% of all cancer. It has been suggested that cancer is a systemic inflammatory disease that generates free radicals causing mutations and releasing trophic factors that favors tumor initiation and cell proliferation. In order to study the effect of formalin-induced inflammation on the development of B16 melanoma, 22 Balb/C mice were divided into three groups: Control Melanoma (CM), Melanoma-Formalin (MF) and Control Formalin (CF). CF and MF groups were injected with 20 µl of 2% formalin on the back of the right paw at the subcutaneous level; CM and MF groups were transplanted with 100,000 melanocytic cells subcutaneously in the plantar surface of the right paw, 24 hours after formalin. CF group mice developed an inflammation that was maximal between the first and second week, then progressively diminished until disappearance by the sixth week. CM group mice developed tumoral macules up to 30 mm², which involute spontaneously. MF group mice developed tumor masses that reached up to 300 mm³ between 3-4 weeks post-transplant and then progressively decreased in volume. CF and MF mice significantly decreased in weight with respect to CM group. In conclusion, inflammation induced by formalin favors tumor development in an allogenic model of malignant melanoma, indicating that anti-inflammatory treatments may be useful in the management of melanoma.

Sintomatología causada por la exposición al formaldehído en estudiantes de medicina y sus posibles mecanismos fisiopatológicos / Symptomatology caused by exposition of medical students to formaldehyde, and its possible pathophysiologic mechanisms / Sintomatologia causada pela exposição ao formaldeído em estudantes de medicina e seus possíveis mecanismos fisiopatológicos

El formaldehído (FA) se utiliza en la preservación de muestras anatómicas. En el programa académico de Medicina se utilizan diversos especímenes preservados con él para el aprendizaje de la Anatomía y la Patología. Durante las prácticas con dichos especímenes es frecuente que haya emisión vapores y contacto directo con el FA, lo que implica niveles altos de exposición; se han informado diversos síntomas según la vía de exposición, más frecuentemente respiratorios y de la piel. Por consiguiente, el FA constituye un riesgo ocupacional para la salud de profesionales y estudiantes cuyas actividades los exponen a él. Este artículo es una revisión de la literatura actual sobre las bases fisiopatológicas y las manifestaciones clínicas asociadas a la exposición a FA en ámbitos académicos, especialmente en estudiantes de Medicina; se incluyen además las medidas de protección.

Formaldehyde (FA) is used for preservation of anatomical specimens that are used during practices of Anatomy and Pathology. Emission of vapors of FA and direct contact with it often occur during such practices, thus exposing students and instructors to this substance. Clinical manifestations of this exposition are mainly respiratory and cutaneous. Therefore, FA constitutes an occupational risk for the health of exposed individuals. This article is a review of recent literature on this subject focused on the clinical manifestations associated to FA exposition and their pathophysiological bases. Protection measures are also included.

O formaldeído (FA) utiliza-se na preservação de mostras anatômicas. No programa acadêmico de Medicina se utilizam diversos espécimenes preservados com ele para a aprendizagem da Anatomia e a Patologia. Durante as práticas com ditos espécimenes é frequente que tenha emissão vapores e contato direto com o FA, o que implica níveis altos de exposição; informaram- se diversos sintomas segundo a via de exposição, mais frequentemente respiratórios e da pele. Portanto, o FA constitui um risco ocupacional para a saúde de profissionais e estudantes cujas atividades os expõem a ele. Este artigo é uma revisão da literatura atual sobre as bases fisiopatológicas e as manifestações clínicas sócias à exposição a FA em âmbitos acadêmicos, especialmente em estudantes de Medicina; incluem-se ademais as medidas de proteção.

Long-term cytotoxic effects of contemporary root canal sealers

Objectives: The aim of the present study was to investigate the effects of root canal sealers on the cytotoxicity of 3T3 fibroblasts during a period of 5 weeks. Material and Methods: Fibroblasts (3T3, 1×105 cells per well) were incubated with elutes of fresh specimens from eight root canal sealers (AH Plus, Epiphany, Endomethasone N, EndoREZ, MTA Fillapex, Pulp Canal Sealer EWT, RoekoSeal and Sealapex) and with elutes of the same specimens for 5 succeeding weeks after immersing in simulated body fluid. The cytotoxicity of all root canal sealers was determined using the MTT assay. Data were analyzed using ANOVA and Tukey's test. Results: RoekoSeal was the only sealer that did not show any cytotoxic effects (p<0.05). All the other tested sealers exhibited severe toxicity initially (week 0). MTA Fillapex remained moderately cytotoxic after the end of experimental period. Toxicity of the other tested sealers decreased gradually over time. The evaluated root canal sealers presented varying degrees of cytotoxicity, mainly in fresh mode.Conclusions: RoekoSeal had no cytotoxic effect both freshly mixed and in the other tested time points. MTA Fillapex was associated with significantly less cell viability when compared to the other tested root canal sealers.

Effects of Co-Administration of Intrathecal Nociceptin/Orphanin FQ and Opioid Antagonists on Formalin-Induced Pain in Rats

PURPOSE: Nociceptin/orphanin FQ (N/OFQ) as an endogeneous hexadecapeptide is known to exert antinociceptive effects spinally. The aims of this study were to demonstrate the antinociceptive effects of i.t. N/OFQ and to investigate the possible interaction between N/OFQ and endogenous opioid systems using selective opioid receptor antagonists in rat formalin tests. MATERIALS AND METHODS: I.t. N/OFQ was injected in different doses (1-10 nmol) via a lumbar catheter prior to a 50 microL injection of 5% formalin into the right hindpaw of rats. Flinching responses were measured from 0-10 min (phase I, an initial acute state) and 11-60 min (phase II, a prolonged tonic state). To observe which opioid receptors are involved in the anti-nociceptive effect of i.t. N/OFQ in the rat-formalin tests, naltrindole (5-20 nmol), beta-funaltrexamine (1-10 nmol), and norbinaltorphimine (10 nmol), selective delta-, micro- and kappa-opioid receptor antagonists, respectively, were administered intrathecally 5 min after i.t. N/OFQ. RESULTS: I.t. N/OFQ attenuated the formalin-induced flinching responses in a dose-dependent manner in both phases I and II. I.t. administration of naltrindole and beta-funaltrexamine dose-dependently reversed the N/OFQ-induced attenuation of flinching responses in both phases; however, norbinaltorphimine did not. CONCLUSION: I.t. N/OFQ exerted an antinociceptive effect in both phases of the rat-formalin test through the nociceptin opioid peptide receptor. In addition, the results suggested that delta- and micro-opioid receptors, but not kappa-opioid receptors, are involved in the antinociceptive effects of N/OFQ in the spinal cord of rats.

Toxicidade animal por formaldeídeo e complucad® em ratos wistar: exposição aguda / Animal toxicity caused by formaldehyde and complucad® in wistar rats: acute exposure

Objetivos: Verificar a toxicidade em ratos Wistar expostos ao formaldeídeo a 10% e Complucad®, analisando-se as enzimas hepáticas alaninaaminotransferase e aspartatoaminotransferase, os tecidos pulmonar, renal e hepático, após período de exposição aguda. Métodos. A amostra contou com 24 ratos machos adultos, da linhagem Wistar-Tecpar, divididos aleatoriamente em três grupos com oito animais cada. O Grupo Controle Negativo (G.C), não foi exposto às substâncias. O Grupo Controle Positivo (G.F) foi exposto ao formaldeído a 1.33 ppm e o Grupo Experimental (G.CP) exposto à substância Complucad®. Os animais foram mantidos sob condições normais de temperatura, com fotoperíodo de 12h claro/escuro, alimentados com ração balanceada para roedores e água ad libitum, sendo expostos diariamente (8 horas/dia) às respectivas substâncias. Após o período de exposição os mesmos foram anestesiados para coleta sanguínea, seguida de eutanásia para coleta dos tecidos. Resultados: O teste ANOVA seguido de TUKEY realizado com nível de significância de 5% demonstrou para a enzima alanina diferença (p=0,04) entre o G.F quando comparado ao controle. A enzima aspartato apresentou (p=0,20). A avaliação histológica dos órgãos demonstrou alteração significativa para o tecido hepático sendo (p=0,0001), tecido pulmonar (p=0,0085) e tecido renal (p=0,00), mediante o teste estatístico com Qui-Quadrado. Através da aplicação do teste Kruskall Wallis 5% para as variáveis dos tecidos, observou-se infiltração de células e perda da arquitetura (p<0,03), dilatação alveolar (p=0,01), tumefação celular cortical, congestão vascular cortical e dilatação tubular (p<0,01). Conclusão: Houve grau de toxicidade aos referidos xenobióticos, sendo em maior intensidade no grupo exposto ao formaldeídeo a 10%.

Objectives: Verify the toxicity in Wistar rats exposed to formaldehyde solutions at 10% and Complucad®, analyzing the alaninaaminotransferase/aspartatoaminotransferase hepatic enzymes and the lung, kidney and liver tissues, after a sharp period of exposition. Methods: The 24 Wistar-Tecpar adult male rats, divided randomly into three groups, with eight animals each group. The Negative Control Group (G.C) was not exposed to the substances; the Positive Control Group (G.F) was exposed to formaldehyde at 1.33 ppm, and the Experimental Group (G. CP) was exposed to Complucad®. The animals were kept under room temperature, in a 12 hour light/dark photo period, fed with a balanced diet for rodents and ad libitum water, being daily exposed (8 hours a day) to the respective substances. After a period of exposition, they were anesthetized for blood collection, then the euthanasia for tissue collection. Results: the ANOVA followed by TUKEY performed with a significance level of 5% showed for enzyme alanine (p=0,04) between the G.F compared with the control group. The enzyme aspartate, showed (p=0,20). The organs histological evaluation showed a significant alteration for the liver tissue, being (p=0,0001), lung tissue (p=0,085), and kidney tissue (p=0.00), before treatment with the Qui-Quadrado Test. Applying the test Kruskall Wallis 5% for the variables of the tissues, observed, cell infiltration and loss of architecture (p=0,03), dilated alveolar (p=0,01), cortical cell swelling, cortical vascular congestion and dilatation tubular (p<0,01). Conclusion: There was a degree of toxicity to the referred xenobiotic, being more intense on the group exposed to formaldehyde at 10%.

Can formaldehyde exposure induce histopathologic and morphometric changes on rat kidney? / ¿La exposición al formaldehído puede inducir cambios histopatológicos y morfométricos sobre el riñón de rata?

Formaldehyde is used traditionally for fixing the cadaver, and vaporized during dissection and practical studying on cadaver. This study was designed to determine the histopathologic and morphometric changes of rat kidney while all of the experiments were exposed to formaldehyde for 18 weeks. 28 male albino Wistar rats were divided into the following three experimental groups (E1: 2hrs/d, 2d/w; E2: 2hrs/d, 4d/w; E3: 4hrs/d, 4d/w) and one control group (C). when the exposure period was expired the animals were anaesthetized with chloroform. After cervical dislocation, the abdomen was dissected and the kidneys were taken. The kidney specimens were sectioned and stained with Haematoxylin and Eosin technique for histologic and morphometric study. Data were obtained from an Olympus light microscope and the analyzed with spss (version 11.5) and ANOVA test. In all histopathology sections of groups E1, E2 and E3, these similar changes were seen: mild glumerolar congestion, focal congestion, and vacuolar degeneration of tubular cells. There were no evidences of inflammatory cells infiltration or fibrotic changes of interstitial tissue. Only mild, non-specific congestion was seen in cortical vessels. Also there were not any abnormalities in the staining of nucleus and cytoplasm. According to Morphometric study, Mean +/- SD of glomerulus's area in control, E1, E2 and E3 group were 10802.66 +/- 1038.18, 10759.50 +/- 1971.88, 10434.73 +/- 1763.76 and 10077.64 +/- 2068.78 micrometer, respectively. Mean +/- SD inner proximal tubule diameter in control, E1, E2 and E3 group were 16.16 +/- 2.49, 16.92 +/- 2.90, 16.31 +/-2.79 and15.66 +/-4.11 µm, respectively. Mean +/- SD of inner distal tubule diameter in control, E1, E2 and E3 group were 15.96 +/- 4.47, 16.20 +/- 1.66, 16.96 +/- 1.63 and17.45 +/- 3.26 µm, respectively. These differences were not significant between cases and control. This study showed that formaldehyde inhalation in 1.5 ppm can not make specific...

El formaldehído se utiliza tradicionalmente para la fijación de cadáveres y vaporiza durante la disección y los estudios prácticos en el cadáver. Este estudio fue diseñado para determinar los cambios histopatológicos y morfométricos de riñones de ratas expuestos al formaldehído, durante 18 semanas. 28 ratas albinas Wistar se dividieron en tres grupos experimentales (E1: 2 h/d, 2d/s, E2: 2 h/d, 4d/s; E3: 4 h/d, 4d/s) y un grupo control (C). Cuando el período de exposición se cumplió los animales fueron anestesiados con cloroformo. Después de la dislocación cervical, el abdomen fue disecado y se obtuvieron los riñones. Los especímenes de riñon fueron seccionados y teñidos con técnica hematoxilina y eosina para el estudio histológico y morfométrico. Los datos fueron obtenidos con un microscopio óptico Olympus, el análisis con el software SPSS (versión 11.5) y la prueba de ANOVA. En todas las secciones histopatológicas de los grupos E1, E2 y E3, se observaron cambios similares: congestión glumerular leve, congestión focal y degeneración vacuolar de las células tubulares. No hubo evidencias de la infiltración de células inflamatorias o cambios de tejido fibrótico intersticial. Sólo una leve congestión no específica fue observada en vasos corticales. Además no hubo anormalidad en la tinción del núcleo y el citoplasma. De acuerdo al estudio morfométrico, la Media +/- DS del área glomerular en los grupos control, E1, E2 y E3 fue 10802,66 +/- 1038,18, 10759,50 +/- 1971,88, 10434,73 +/-1763,76 y 10077,64 +/- 2068,78 µm, respectivamente. La Media +/- DS del diámetro interno del túbulo proximal en los grupos control, E1, E2 y E3 fueron 16,16 +/- 2,49, 16,92 +/- 2,90, 16,31 +/- 2,79 y 15,66 +/- 4,11 µm, respectivamente. La Media +/- SD del diámetro interno de los túbulos distales en los grupos control, E1, E2 y E3 fueron 15,96 +/- 4,47, 16,20 +/- 1,66, 16,96 +/- 1,63 y 17,45 +/- 3,26 µm, respectivamente. Estas diferencias no fueron significativas entre los casos...

Additive Antinociception between Intrathecal Sildenafil and Morphine in the Rat Formalin Test

The possible characteristics of spinal interaction between sildenafil (phosphodiesterase 5 inhibitor) and morphine on formalin-induced nociception in rats was examined. Then the role of the opioid receptor in the effect of sildenafil was further investigated. Catheters were inserted into the intrathecal space of male Sprague-Dawley rats. For induction of pain, 50 microliter of 5% formalin solution was applied to the hindpaw. Isobolographic analysis was used for the evaluation of drug interaction between sildenafil and morphine. Furthermore, naloxone was intrathecally given to verify the involvement of the opioid receptor in the antinociception of sildenafil. Both sildenafil and morphine produced an antinociceptive effect during phase 1 and phase 2 in the formalin test. The isobolographic analysis revealed an additive interaction after intrathecal delivery of the sildenafil-morphine mixture in both phases. Intrathecal naloxone reversed the antinociception of sildenafil in both phases. These results suggest that sildenafil, morphine, and the mixture of the two drugs are effective against acute pain and facilitated pain state at the spinal level. Thus, the spinal combination of sildenafil with morphine may be useful in the management of the same state. Furthermore, the opioid receptor is contributable to the antinocieptive mechanism of sildenafil at the spinal level.

Formaldehyde levels in absorbent paper points through hplc

Formaldehyde tablets have been frequently used to keep absorbent paper points sterilized. However, the toxicity of this drug must be considered. The present study aims to determine rates of formaldehyde impregnation in absorbent paper points kept in environments containing formaldehyde tablets. Thus, an accurate analytical methodology requiring simple operations and providing the determination of low concentration levels (ppm) of the formaldehyde impregnated in absorbent paper points was used. The absorbent paper points which had been kept in environments containing formaldehyde tablets were placed in test tubes containing 2.4-dinitrophenylhydrazine and, following an ultrasound bath, were transferred to a microcolumn and washed withdistilled water. The retained hydrazones were diluted in acetonitrile and the amount of 10ml was injected in the High Performance Liquid Chromatographer. The results were subjected to descriptive statistics encompassing the estimation of mean values, the standard deviation, and the confidence interval (95%) for mean values. This study showed a significant rate of formaldehyde impregnation in absorbent paper points of any size, especially in those kept in environments containing formaldehyde tablets over a seven-day period.

Formaldeído na odontologia: aspectos antimicrobianos, carcinogênicos e mutagênicos. Um estudo da sua viabilidade na clínica odontológica / Formaldehyde in dentistry: antimicrobial, carcinogenic, and mutagenic aspects. A study of its viability in dentistry

O formaldeído é um medicamento usado na prática odontológica desde o século XVIII. Ele foi um dos agentes medicamentosos mais usados na Odontologia, ao se tratar de terapêutica pulpar. Porém, apesar de apresentar alto índice de sucesso clínico e radiográfico, têm-se dado atenção especial para as propriedades tóxicas deste material. O presente artigo visa revisar a ação do formaldeído sobre os tecidos dentários, enfatizando os aspectos citotóxicos e antimicrobianos, considerando sua ação sobre cultura de células e de bactérias, em diferentes concentrações, e seus efeitos mutagênicos e carcinogênicos. Pode-se concluir que, apesar de ser um eficiente antimicrobiano, o formaldeído apresenta numerosos efeitos citopatológicos, além de ser mutagênico e carcinogênico.

Toxic effects of embalming fluid on medical students and professionals.

Vapours of embalming fluid in the dissection room are a perennial cause of irritation to the mucous membranes of the pharynx, upper respiratory tract and eyes. We made an attempt to assess the discomfort level produced by formalin and that produced by the standardized embalming fluid used in our department. A list of twenty symptoms was made and circulated among students attending dissection and students were asked to grade the severity of each symptom experienced on a scale of 1 to 4. Individual scores of each symptom were statistically compared and summated, and the same reflected the general acceptability of the embalming fluid.

Study of the inflammatory process induced by injection of carrageenan or formalin in the rat temporomandibular joint

O objetivo deste trabalho foi avaliar os efeitos da injecão de dois agentes flogísticos, ou seja, carragenina ou formalina, na ATM do rato, e a evolucão do quadro inflamatório provocado por essas substâncias. Foram utilizados 45 ratos, divididos em dois grupos experimentais e um grupo controle. Os animais foram sacrificados em lotes de três de cada grupo após três horas, 24 horas, três dias, sete dias e 15 dias da injecão. Histologicamente a reacão inflamatória em ambos os grupos experimentais iniciou-se com infiltrado inflamatório agudo, tornando-se misto e depois crônico. Sinais de hiperplasia da membrana sinovial foram observados aos três dias, intensos aos sete dias, estando presentes aos 15 dias somente no grupo da formalina. A injecão de solucão salina (grupo controle) não provocou reacão inflamatória. No presente trabalho foi concluído que uma injecão local única na região da ATM de carragenina ou de formalina foi suficiente para induzir reacão inflamatória na articulacão e nos tecidos moles periarticulares. As reacões inflamatórias resultantes da injecão desses agentes flogísticos foram semelhantes, mas o grupo da formalina mostrou infiltrado inflamatório mais persistente.

Pre-versus post-formalin effects of intrathecal ketamine on spinal Fos-like immunoreactivity in rats.

BACKGROUND & OBJECTIVES: The spinal expression of the c-Fos immediate early gene in response to formalin pain of the hind paw of rat was used as a marker of neuronal activity. Ketamine, a Nmethyl-D-aspartate (NMDA) receptor antagonist produces analgesic action due to the blockade of glutamate action at the NMDA receptor. Earlier study showed that ketamine acts differently depending on its route of administration. We undertook this study to compare a preemptive suppression of noxious stimulation induced spinal Fos-like immunoreactivity (FLI) after receiving intrathecal ketamine before or after formalin pain. METHODS: Male Sprague-Dawley rats received ketamine 1 mg/kg or saline (control group) intrathecally either 5 min before (pre-treatment group) formalin or 5 min after (post-treatment group) formalin (5%, 50 microl) injection. Animals were killed 2 h after the formalin injection, and the lumbar spinal cord was dissected, and processed by immunoperoxidase staining using an antibody against Fos protein. RESULTS: The FLI was significantly reduced in the pre-treatment group, only laminae I-II of the side ipsilateral to the formalin injection (P < 0.05 vs. control). In laminae V-VI, neither of the ketamine treatment groups showed a significant decrease than the control group. INTERPRETATION & CONCLUSION: The results provide evidence that intrathecal ketamine does not have a preemptive blocking effect of FLI expression in whole spinal laminae area. FLI expression of laminae I-II only might not be a good predictor of the ability of agents to produce preemptive effect. The central patterns of activity generated during central sensitization differ regionally in the spinal dorsal horn.

Interaction between Intrathecal Gabapentin and Adenosine in the Formalin Test of Rats

Spinal gabapentin and adenosine have been known to display an antinociceptive effect. We evaluated the nature of the interaction between gabapentin and adenosine in formalin-induced nociception at the spinal level. Male Sprague-Dawley rats were prepared for intrathecal catheterization. Pain was evoked by injection of formalin solution (5%, 50 microliter) into the hindpaw. After examination of the effects of gabapentin and adenosine, the resulting interaction was investigated with isobolographic and fractional analyses. Neither gabapentin nor adenosine affected motor function. Gabapentin or adenosine decreased the sum of the number of flinches during phase 2, but not during phase 1 in the formalin test. Isobolographic analysis, in phase 2, revealed an additive interaction between gabapentin and adenosine. Taken together, intrathecal gabapentin and adenosine attenuated the facilitated state and interacted additively with each other.

Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium

The increasing use of alcohol as an alternative fuel to gasoline or diesel can increase emission of formaldehyde, an organic gas that is irritant to the mucous membranes. The respiratory system is the major target of air pollutants and its major defense mechanism depends on the continuous activity of the cilia and the resulting constant transportation of mucous secretion. The present study was designed to evaluate the effects of formaldehyde on the ciliated epithelium through a relative large dose range around the threshold limit value adopted by the Brazilian legislation, namely 1.6 ppm (1.25 to 5 ppm). For this purpose, the isolated frog palate preparation was used as the target of toxic injury. Four groups of frog palates were exposed to diluted Ringer solution (control, N = 8) and formaldehyde diluted in Ringer solution at three different concentrations (1.25, 2.5 and 5.0 ppm, N = 10 for each group). Mucociliary clearance and ciliary beat frequency decreased significantly in contact with formaldehyde at the concentrations of 2.5 and 5.0 ppm after 60 min of exposure (P<0.05). We conclude that relatively low concentrations of formaldehyde, which is even below the Brazilian threshold limit value, are sufficient to cause short-term mucociliary impairment

Formaldehído: efectos tóxicos y recomendaciones / Formaldehyde: toxis effects and recomendatoris

Personas de la profesión médica y del área de la salud en general, estudiantes de los departamentos de anatomía normal o patologica, histología etc; o profesores, técnicos, obreros y empleados de estas áreas, utilizan y están en contacto directo con una sustancia que desde hace más de una década está siendo analizada y estudiada para comprobar sus efectos tóxicos; el formaldehído. He podido observar que un gran número de personas expuestas al formaldehído, aunque conocen los efectos mediatos (irritación de la mucosa nasal, lagrimeo profuso, tos etc) desconocen la mayoría de los efectos y daños a la salud que esta sustancia puede ocasionar a largo plazo y como consecuencia de exposiciones repetidas, otras personas están al tanto de los efectos pero no toman las medidas del caso. También sugiero medidas de seguridad tomadas en su mayor parte de los estándares norteamericanos que dicta la Agencia para la Protección del Ambiente (US. EPA) y la Agencia para la salud y seguridad ocupacional (OSHA)

Gradual decline of formaldehyde-induced male recombination in successive generations of Drosophila melanogaster.

Transmission of formaldehyde (FA)-induced male recombination was studied in D. melanogaster for three generations. Among recombinants, al dp was the most and b pr the next most frequent phenotype in the progenies of F1, TC1, TC2 and TC3 males of genotype + /al dp br. Non-reciprocal male recombination for dp-b and b-pr regions whereas reciprocal male recombination for al-dp region were noted. Percentages of recombinants observed in TC1 (1.052), TC2 (0.876), TC3 (0.698) and TC4 (0.497) progenies of D. melanogaster males were not statistically different from each other in any two successive generations. A continuous but gradual decline in the frequency of FA-induced male recombination was observed in the three subsequent generations studied.