Citral inhibits the nociception in the rat formalin test: effect of metformin and blockers of opioid receptor and the NO-cGMP-K+ channel pathway.

The objective of the present study was to scrutinize the effect of nitric oxide (NO), cyclic GMP (cGMP), potassium channel blockers, and metformin on the citral-produced peripheral antinociception. The rat paw 1% formalin test was used to assess nociception and antinociception. Rats were treated with local peripheral administration of citral (10-100 µg/paw). The antinociception of citral (100 µg/paw) was evaluated with and without the local pretreatment of naloxone, NG-L-nitro-arginine methyl ester (L-NAME, a NO synthesis inhibitor), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, a soluble guanylyl cyclase inhibitor), metformin, opioid receptors antagonists, and K+ channel blockers. Injection of citral in the rat paw significantly decreased the nociceptive effect of formalin administration during the two phases of the test. Local pretreatment of the paws with L-NAME and ODQ did not reduced the citral-induced antinociception. Glipizide or glibenclamide (Kir6.1-2; ATP-sensitive K+ channel blockers), tetraethylammonium or 4-aminopyridine (KV; voltage-gated K+ channel blockers), charybdotoxin (KCa1.1; big conductance calcium-activated K+ channel blocker), apamin (KCa2.1-3; small conductance Ca2+-activated K+ channel antagonist), or metformin, but not the opioid antagonists, reduced the antinociception of citral. Citral produced peripheral antinociception during both phases of the formalin test. These effects were due to the activation of K+ channels and a biguanide-dependent mechanism.

Neonatal pain modulates in adolescent rats the antinociceptive effects of fluoxetine and buspirone administrated to their depressive dams during gestation.

Previously, we have shown that the administration of a selective serotonin reuptake inhibitor fluoxetine or a 5-HT1A receptor agonist buspirone to stressed rats during gestation causes in the offspring alleviation of formalin-induced pain, strengthened by prenatal stress. We have also found that neonatal inflammatory pain strengthens formalin-induced pain in prenatally unstressed rats in later life. In the present study, we investigated the effect of neonatal inflammatory pain on the time-course of the biphasic pain response in the formalin test in prenatally stressed adolescent rats of both sexes to evaluate whether neonatal pain affects the antinociceptive properties of these drugs administered to their depressed mothers during gestation. Our findings demonstrate that neonatal pain modulates in prenatally stressed rats the antinociceptive effect of fluoxetine and buspirone depending on the level of organization of pain response in the central nervous system, the phase of the time-course of the formalin-induced pain, and sex of the rat.

Participation of the opioid receptor - nitric oxide - cGMP - K+ channel pathway in the peripheral antinociceptive effect of nalbuphine and buprenorphine in rats.

The aim of this study was to examine if the peripheral antinociceptive effects of the opioid agonist/antagonist nalbuphine and buprenorphine involve the sequential participation of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) synthesis followed by K+ channel opening in the formalin test. Wistar rats (180-220 g) were injected in the dorsal surface of the right hind paw with formalin (1%). Rats received a subcutaneous (s.c.) injection into the dorsal surface of the paw of vehicles or increasing doses of nalbuphine (50-200 µg/paw) or buprenorphine (1-5 µg/paw) 20 min before formalin injection into the paw. Nalbuphine antinociception was reversed by the s.c. injection into the paw of the inhibitor of NO synthesis (NG-nitro-l-arginine methyl ester (L-NAME)), by the inhibitor of guanylyl cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ)), by the Kir6.1-2, ATP-sensitive K+ channel inhibitors (glibenclamide and glipizide), by the KCa2.1-3, small conductance Ca2+-activated K+ channel blocker (apamin), by the KCa1.1, large conductance Ca2+-activated K+ channel blocker (charybdotoxin), and by the KV, voltage-dependent K+ channel inhibitors (4-aminopyridine (4-AP) and tetraethylammonium chloride (TEA)). The antinociceptive effect produced by buprenorphine was blocked by the s.c. injection of 4-AP and TEA but not by L-NAME, ODQ, glibenclamide, glipizide, apamin, or charybdotoxin. The present results provide evidence for differences in peripheral mechanisms of action between these opioid drugs.

Local antinociceptive action of fluoxetine in the rat formalin assay: role of l-arginine/nitric oxide/cGMP/KATP channel pathway.

The present study was conducted to evaluate the local antinociceptive actions of fluoxetine, a selective serotonin reuptake inhibitor, and the possible involvement of the l-arginine/NO/cGMP/KATP channel pathway in this effect using the formalin test in rats. To elucidate the underlying mechanisms, animals were pre-treated with l-NAME, aminoguanidine, methylene blue, glibenclamide, l-arginine, sodium nitroprusside, or diazoxide. Local ipsilateral, but not contralateral, administration of fluoxetine (10-300 µg/paw) dose-dependently suppressed flinching number during both early and late phases of the test, and this was comparable with morphine also given peripherally. Pre-treatment with l-NAME, aminoguanidine, methylene blue, or glibenclamide dose-dependently prevented fluoxetine (100 µg/paw)-induced antinociception in the late phase. In contrast, administration of l-arginine, sodium nitroprusside, and diazoxide significantly enhanced the antinociception caused by fluoxetine in the late phase of the test. However, these treatments had no significant effect on the antinociceptive response of fluoxetine in the early phase of the formalin test. Our data demonstrate that local peripheral antinociception of fluoxetine during the late phase of the formalin test could be due to activation of l-arginine/NO/cGMP/KATP channel pathway. The peripheral action of fluoxetine raises the possibility that topical application of this drug (e.g., as a cream, ointment, or jelly) may be a useful method for relieving the inflammatory pain states.

A Prospective Study of Distal Microscopic Spread in Rectal Cancer After Neoadjuvant Chemoradiation in Pinned and Unpinned Specimen.

The most important margin in determining the prognosis of rectal cancer is circumferential resection margin (CRM). But, the type of surgery is determined by distal rectal margin (DRM), whether sphincter saving procedure is possible or patient needs an abdominoperineal resection. There are no standardized uniform guidelines for measurement of DRM. The purpose of this study is to assess the distal microscopic spread beyond gross margin after neoadjuvant concurrent chemoradiation (CCRT) in rectal cancers, the factors influencing the distal microscopic spread, the shrinkage of the distal margin in pinned and unpinned fresh and fixed specimen, and to find out the best method of measurement of distal rectal margin. A prospective analytical study was conducted from May 2013 through February 2015 in 47 cases of carcinoma rectum (both AR and APR) who had received neoadjuvant CCRT. Fresh specimen was collected within 30 min of specimen retrieval and a longitudinal cut was made in the distal margin of all specimens. One side of the specimen was pinned onto a cork board and the other side was left unpinned. Measurements were made from the distal end of clinical gross tumor. DRM was determined in both pinned and unpinned sides in fresh and fixed specimen. Of the 47 patients, 2 patients (4.2%) had small focus of tumor beyond gross margins, 1 at 6 mm and another at 3.5 mm on the unpinned side. The average margin for fresh and fixed pinned specimens was 3.67 and 3.47 cm, respectively, with percentage shrinkage of 5.4% for the pinned specimens. The average margin for fresh and fixed unpinned specimens was 3.32 and 2.84 cm, respectively, with percentage shrinkage of 14.4% for the unpinned specimens. Six patients (12.7%) had complete pathological response. Correlation of distal margin was better in pinned specimen. A correction factor of 15% for shrinkage needs to be taken into account while assessing unpinned specimen. Only in 4.2% of patients, there was distal submucosal spread beyond gross margin. Long-term follow up is required for assessing adequacy of DRM post neoadjuvant CCRT.

Avaliação de diferentes fixadores na preservação das características histológicas de pele de orelha de cães / Evaluation of different fixatives for histological studies in canine ear skin

Os fixadores biológicos desempenham um papel importante na qualidade final da histologia. Na rotina veterinária, a biópsia de pele é um procedimento comum e a escolha do fixador é primordial para resultado final adequado. Os fixadores mais usados são à base de formalina, ainda que sejam tóxicos, cancerígenos, de baixa penetração e de fixação lenta. Mesmo assim, não existe um fixador ideal que substitua as suas qualidades. O objetivo deste trabalho foi avaliar qualitativamente a preservação das características histológicas de pele de cão utilizando diferentes fixadores de tecidos incluídos em parafina, cortados e corados pela hematoxilina-eosina. Utilizou-se uma caneta Punch de 4 milímetros para coletar amostras de pele de orelha em seis cadáveres de cães. Após coleta, os tecidos foram fixados em: (1) Bouin, durante seis horas; (2) Carnoy, durante quatro horas; (3) formaldeído tamponado 10% durante 24 horas, todos sob refrigeração (4ºC). Posteriormente, os tecidos foram processados, cortados e corados em hematoxilina e eosina. As lâminas foram avaliadas, às cegas, por quatro patologistas diferentes, que consideraram aspectos qualitativos a seguir: (1) qualidade da coloração; (2) preservação das características histológicas; e (3) preservação dos limites citoplasmáticos utilizando a escala de LIKERT de pontuação para cada lâmina. O fixador com a maior média de pontuação em todos os itens foi o formol tamponado com 3,76 pontos, seguido pelo Bouin (3,39) e pelo Carnoy (2,52). O formol pode trazer riscos à saúde do profissional que rotineiramente o manuseia, portanto se faz necessária a busca por fixadores com as mesmas qualidades, mas menos nocivos à saúde.(AU)

The biological fixatives have an important role in the final histology quality. In veterinary, routine skin biopsy is a common procedure and the choice of fixative is essential for the final result. The most common fixative is Formalin, even though it is toxic, carcinogenic, and has low and slow penetration. Still, there isn't a fixer which can replace the qualities of formalin. The aim of this study was to evaluate qualitatively the preservation of the histological features of dog skin using different tissue fixative embedded in paraffin, sectioned and stained with hematoxylin - eosin. We used a 4 mm punch pen to collect ear skin samples in six dog cadavers. After collection, the tissues were fixed in: (1) Bouin for 6 hours; (2) Carnoy for 4 hours; (3) 10% buffered formaldehyde for 24 hours, all under refrigeration (4 ° C). The tissues were then processed, sectioned and stained with hematoxylin and eosin. The slides were evaluated blindly by four different pathologists who considered the qualitative aspects below: (1) quality of coloring; (2) preservation of the histological characteristics; (3) preservation of cytoplasmic boundaries using a Likert scale score for each blade. The fixative with the highest mean score on all items was buffered formalin with 3.76 points followed by Bouin (3.39) and Carnoy (2.52). Formaldehyde can bring health a risk of professional routine handling, so it is necessary to search for a biological fixative with the same qualities being less harmful to health.(AU)

Antinociceptive properties of shikonin: in vitro and in vivo studies.

Shikonin possess a diverse spectrum of pharmacological properties in multiple therapeutic areas. However, the nociceptive effect of shikonin is not largely known. To investigate the antinociceptive potential of shikonin, panel of GPCRs, ion channels, and enzymes involved in pain pathogenesis were studied. To evaluate the translation of shikonin efficacy in vivo, it was tested in 3 established rat pain models. Our study reveals that shikonin has significant inhibitory effect on pan sodium channel/N1E115 and NaV1.7 channel with half maximal inhibitory concentration (IC50) value of 7.6 µmol/L and 6.4 µmol/L, respectively, in a cell-based assay. Shikonin exerted significant dose dependent antinociceptive activity at doses of 0.08%, 0.05%, and 0.02% w/v in pinch pain model. In mechanical hyperalgesia model, dose of 10 and 3 mg/kg (intraperitoneal) produced dose-dependent analgesia and showed 67% and 35% reversal of hyperalgesia respectively at 0.5 h. Following oral administration, it showed 39% reversal at 30 mg/kg dose. When tested in first phase of formalin induced pain, shikonin at 10 mg/kg dose inhibited paw flinching by ∼71%. In all studied preclinical models, analgesic effect was similar or better than standard analgesic drugs. The present study unveils the mechanistic role of shikonin on pain modulation, predominantly via sodium channel modulation, suggesting that shikonin could be developed as a potential pain blocker.

Medidas de bioseguridad en una sala de disección de anatomía patológica / Biosecurity measures in a dissecting room pathology

El objetivo principal es analizar las medidas de bioseguridad en el laboratorio de disecciÓn de anatomía patolÓgica del hospital Max Peralta en Cartago. Con el fin de valorar los riesgos asociados con la exposición al forma debido, se utilizaron las guías de referencia de la Administración en Salud y Seguridad Ocuapcional (OSHA) y del Instituto Nacional de Salud y Seguridad (NIOSH). Tomando en cuenta tres variables: uso de medidas de protección, diseño del laboratorio y ventilación. Los datos fueron analizados en el mes de diciembre del 2009. Se encontró que en la sala de disección no existe un adecuado sistema de ventilación para evitar la acumulación de formalina en el aire. El personal que labora allí si toma las medidas de seguridad para protección personal. El diseño de la sala cumple con la mayor parte de los requerimientos tales como que se encuentre separado del area de oficinas, presencia de lavamanos y mesas de materiales resistente que permitan una fácil limpieza y desinfección. Pero los estantes que se encuentran en el pasillo principal en los cuales se almacenan tejidos para la docencia, no se encuentran asegurados a la pared, lo que evidencia un potencial riesgo en caso de sismo o incendio al obstruir la única salida del laboratorio. Conclusión: Es importante identificar los riesgos en el lugar de trabajo que podrían causar daño. Deben anticiparse y evaluarse cuidadosamente la prevención de riesgo y salud, para que se incorporen medidas de diseño recomendadas según sea posible. Si embargo, no importa que tan bien estructurado esté un laboratorio, pues su uso inapropiado puede producir riesgos laborales...

A Case of Re-Dissection of Aortic Root after Reconstruction of Acute Aortic Dissection / 日本心臓血管外科学会雑誌

A 69-year-old man had been treated with total arch replacement for acute Stanford type A aortic dissection. He had cardiac failure at 9 years after his previous operation. Computed tomography and transesophageal echocardiography showed re-dissection of the aortic root and aortic regurgitation. He was referred to our hospital for surgical treatment. In the second operation, aortic root replacement was performed. Re-dissection of the aortic root at the site of the non-coronary sinus was noted intraoperatively, and intraoperative findings suggested necrosis of the aortic wall related to the use of GRF glue. Care should be taken to ensure proper use of GRF glue. The aortic root replacement using a Freestyle valve provided good hemodynamic function and low thrombogenicity. The use of this valve in this case which had residual dissection of the descending aorta seemed useful because of the excellent hemodynamic function without anticoagulant therapy.