Light-curing of calcium hydroxide-based liners: pH analysis and calcium ion release / Fotoativação de forradores a base de hidróxido de cálcio: análise de pH e liberação de íons cálcio

Objective: Compare the pH values and calcium ion release of calcium hydroxide-based liner materials before and after light-curing. Material and Methods: The materials evaluated were: hydrox-cal white (HW), hydrox-cal dentin (HD), Biocal (BC) and UltraBlend Plus (UB). 120 samples of the liner materials were inserted into a PVC tube (n=15). The samples from HW+A, HD+A, BC+A and UB+A were subjected to photoactivation. The other groups HW+N, HD+N, BC+N and UB+N were only inserted in a glass tube with deionized water. The pH was measured 24 hours and 14 days after the inclusion of the samples with the aid of a pH meter. The calcium release was analyzed with the aid of an atomic absorption spectophotometer at 24h and 14 days. The results were submitted to the Shapiro-Wilk test, followed by ANOVA and Tukey test (p=0.05). Results: In 24h, the groups that were not light cured showed the highest pH values (p<0.05). In 14 days, BC+N and BC+A demonstrated the lowest pH values. The groups that were not light cured also showed higher calcium release values in 24h and 14 days (p<0.05). Conclusion: Photoactivation of calcium hydroxide-based liner materials negatively interferes with calcium ion release, as well as with pH.(AU)

Objetivo: Comparar os valores de pH e liberação de íons cálcio de materiais forradores à base de hidróxido de cálcio antes e depois da fotopolimerização. Material e métodos: Os materiais avaliados foram: Hidrox-cal branco (HW), Hidrox-cal dentina (HD), Biocal (BC) e UltraBlend Plus (UB). 120 amostras dos materiais de revestimento foram inseridas em um tubo de PVC (n=15). As amostras de HW +A, HD+A, BC+A e UB+A foram submetidas à fotoativação. Os demais grupos HW +N, HD+N, BC+N e UB+N foram inseridos apenas em um tubo de vidro com água deionizada. O pH foi medido 24 horas e 14 dias após a inclusão das amostras com o auxílio de um medidor de pH. A liberação de cálcio foi analisada com o auxílio de um espectrofotômetro de absorção atômica em 24h e 14 dias. Os resultados foram submetidos ao teste de Shapiro-Wilk, seguido de ANOVA e teste de Tukey (p=0,05). Resultados: Em 24h, os grupos não fotopolimerizados apresentaram os maiores valores de pH (p<0,05). Em 14 dias, BC+N e BC+A apresentaram os menores valores de pH. Os grupos não fotopolimerizados também apresentaram maiores valores de liberação de cálcio em 24h e 14 dias (p<0,05). Conclusão: A fotoativação de materiais de revestimento à base de hidróxido de cálcio interfere negativamente na liberação de íons cálcio e no pH (AU)

Lidocaína 2 % con adrenalina 1: 80000 alcalinizada con bicarbonato de sodio 8, 4 % en la anestesia dental / Lidocaine 2% with adrenaline 1: 80,000 alkalinized with sodium bicarbonate 8. 4 % in dental anesthesia

Introducción: La alcalinización de la lidocaína ha resultado ser exitosa en el bloqueo del nervio dentario inferior, sin embargo, existen resultados contradictorios respecto a su eficacia clínica. Objetivo: Determinar el efecto de la lidocaína 2 por ciento con adrenalina 1:80000 alcalinizada con bicarbonato de sodio al 8,4 % sobre el bloqueo del nervio dentario inferior. Material y métodos: Estudio experimental, prospectivo y longitudinal conformado por 50 pacientes de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos. Las siguientes soluciones fueron administradas para el bloqueo del nervio dentario inferior: lidocaína 2 por ciento con adrenalina 1:80000 alcalinizada con bicarbonato de sodio al 8,4 por ciento y lidocaína 2 por ciento con adrenalina 1:80000 no alcalinizada. Se evaluó la intensidad del dolor por la inyección, parámetros hemodinámicos y periodos anestésicos (tiempo de inicio de acción y duración del efecto anestésico). Resultados: Se evidenció una menor intensidad del dolor por la inyección en el grupo de lidocaína alcalinizada (19,16 ± 2,7) en comparación al grupo de lidocaína no alcalinizada (22,88 ± 4,2); p=0,02. Así mismo, el tiempo de inicio de acción fue menor en el grupo de lidocaína alcalinizada (105,72 ± 9,7s) en comparación con el grupo de lidocaína no alcalinizada (157,52 ± 12,1); p=0,002. Sin embargo, no se evidenciaron diferencias significativas en los parámetros hemodinámicos (p>0,05) y la duración del efecto anestésico (p=0,114). Conclusiones: La lidocaína 2 por ciento con adrenalina 1:80000 alcalinizada con bicarbonato de sodio al 8,4 por ciento sobre el bloqueo del nervio dentario inferior produce una disminución de la intensidad del dolor por la inyección y del tiempo de inicio de acción, en comparación con la formulación no alcalinizada. Sin embargo, no se evidencian diferencias en relación con los parámetros hemodinámicos ni a la duración del efecto anestésico(AU)

Introduction: The alkalinization of lidocaine has been successful in blocking the inferior dental nerve; however, there are contradictory results regarding its clinical efficacy. Objective: To determine the effect of 2 percent lidocaine with 1: 80,000 adrenaline alkalinized with 8.4 percent sodium bicarbonate on inferior dental nerve block. Material and methods: Experimental, prospective and longitudinal study that comprised 50 patients from the Dental School of the National University of San Marcos. The following solutions were administered for inferior dental nerve block: 2 percent lidocaine with epinephrine 1: 80,000 alkalinized with 8.4 percent sodium bicarbonate and 2 percent lidocaine with 1: 80,000 adrenaline not alkalinized. Pain intensity was evaluated by injection, hemodynamic parameters and anesthetic periods (time of onset of action and duration of the anesthetic effect). Results: There was a lower pain intensity due to injection in the alkalized lidocaine group (19.16 ± 2.7) compared to the non-alkalinized lidocaine group (22.88 ± 4.2); p=0.02. Likewise, the onset time of action was lower in the alkalized lidocaine group (105.72 ± 9.7) compared to the non-alkalinized lidocaine group (157.52 ± 12.1); p=0.002. However, no significant differences were found in the hemodynamic parameters (p>0.05) and the duration of the anesthetic effect (p=0.114). Conclusions: Lidocaine 2 percent with adrenaline 1: 80,000 alkalized with sodium bicarbonate at 8.4 percent on the block of the inferior dental nerve produces a decrease in pain intensity due to injection and the time of onset of action, compared to the non-alkalinized formulation. However, there are no differences in relation to the hemodynamic parameters or the duration of the anesthetic effect(AU)

Ácido 2-4 diclorofenoxiacético, un herbicida olvidado: reporte de dos casos / 2-4 dichlorophenoxyacetic acid, a forgotten herbicide: Two case report / Ácido 2-4 diclorofenoxiacético, um herbicida esquecido: reporte de dois casos

Los plaguicidas están entre las principales causas de intoxicación por sustancias químicas en Colombia. Entre ellos se cuentan herbicidas como el paraquat, el glifosato y el ácido 2,4-diclorofenoxiacético (2,4-D). Este último es uno de los herbicidas más usados en el mundo y la intoxicación por causa de este tiene una presentación similar a la intoxicación por inhibidores de la colinesterasa. El abordaje clínico de la intoxicación por 2,4-D es un reto para el primer respondiente, pues el cuadro sintomático es amplio dados los diferentes efectos de la sustancia, entre los que están el gastrointestinal, el metabólico, el renal, el neurológico, y, por supuesto, el toxicológico. Si bien la alcalinización urinaria es una piedra angular del manejo, cada vez hay más información sobre la efectividad y seguridad del uso de la hemodiálisis en casos graves. En este reporte se presentan los casos de dos pacientes con ingesta de 2,4-D, los únicos reportados en Colombia.

In Colombia one of the main sources of intoxication for chemical compounds are pesticides, finding in this groups herbicides like Paraquat, Glyphosate and 2,4-D, the last is one of the most used herbicides worldwide, finding similar clinical manifestations from those intoxications due to cholinesterase inhibitors. The access to this patient might represent a great challenge for the primary responder, because the symptomatic manifestations are wide due to the different risks it configures, like gastrointestinal, metabolic, renal, neurologic, and toxicological risk. Urinary alkalization was the recommended strategy for the management of this intoxication, but the evidence so far shows better safety and effectiveness using hemodialysis in the most severe cases. Then, the clinical cases of two patients with 2,4-D intake are presented, being those the only ones reported in Colombia so far.

Os praguicidas estão entre as principais causas de intoxicação por substâncias químicas na Colômbia. Entre eles se encontram herbicidas como o Paraquat, o glifosato e o ácido 2,4-diclorofenoxiacético (2,4-D). Este último é um dos herbicidas mais usados no mundo e a intoxicação por causa deste tem uma apresentação similar à intoxicação por inibidores da colinesterase. A abordagem clínica da intoxicação por 2,4-D é um desafio para o primeiro respondente, pois o quadro sintomático é amplo dados os diferentes efeitos da substância, entre os que está o gastrointestinal, o metabólico, o renal, o neurológico, e, por suposto, o toxicológico. Se bem que a alcalinização urinária é uma pedra angular do manejo, cada vez mais há mais informação sobre a efetividade e segurança do uso da hemodiálise nos casos graves. Neste reporte se apresentam os casos de dois pacientes com ingestão de 2,4-D, os únicos reportados na Colômbia.

Impact of extracellular alkalinization on the survival of human CD24-/CD44+ breast cancer stem cells associated with cellular metabolic shifts

Cancer stem cells reside in a distinct region within the tumor microenvironment that it is believed to play a fundamental role in regulating stemness, proliferation, survival, and metabolism of cancer cells. This study aimed to analyze the effect of extracellular alkalinization on metabolism and survival of human CD24-/CD44+ breast cancer stem cells (BCSCs). BCSCs were cultured in alkalinized DMEM-F12 and incubated at 37°C, 5% CO2, and 20% O2 for 30 min, 6, 24, and 48 h. After each incubation period, we analyzed the modulation of various mRNA expressions related to pH and cellular metabolic regulation using the qRT-PCR. Metabolic state was measured using colorimetric and fluorometric assays. To examine cell proliferation and apoptosis, we used trypan blue and annexin V/propidium iodide assay, respectively. This study demonstrated that alkalinization could stimulate extracellular carbonic anhydrase (CAe) activity, as well as CA9 and HIF1α expression. Under alkaline pH and HIF1α regulation, glucose consumption, extracellular lactate production, and LDH activity of BCSCs were upregulated while O2 consumption was downregulated. These metabolic shifts seemed to promote apoptosis and suppress the proliferation of BCSCs. To conclude, modulation of the extracellular environment through alkalinization could change the metabolic states of BCSCs, which in turn affect the cell survival.

Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

OBJECTIVE: To evaluate at which pH level various local anesthetics precipitate, and to confirm which combination of corticosteroid and local anesthetic crystallizes. METHODS: Each of ropivacaine-HCl, bupivacaine-HCl, and lidocaine-HCl was mixed with 4 different concentrations of NaOH solutions. Also, each of the three local anesthetics was mixed with the same volume of 3 corticosteroid solutions (triamcinolone acetonide, dexamethasone sodium phosphate, and betamethasone sodium phosphate). Precipitation of the local anesthetics (or not) was observed, by the naked eye and by microscope. The pH of each solution and the size of the precipitated crystal were measured. RESULTS: Alkalinized with NaOH to a certain value of pH, local anesthetics precipitated (ropivacaine pH 6.9, bupivacaine pH 7.7, and lidocaine pH 12.9). Precipitation was observed as a cloudy appearance by the naked eye and as the aggregation of small particles (300 µm, pH 7.5). Ropivacaine with dexamethasone sodium phosphate also precipitated, but it was only observable by microscope (a few crystals of 10-100 µm, pH 7.0). Bupivacaine with betamethasone sodium phosphate formed precipitates of non-aggregated smaller particles (<10 µm, pH 7.7). Lidocaine mixed with corticosteroids did not precipitate. CONCLUSION: Ropivacaine and bupivacaine can precipitate by alkalinization at a physiological pH, and therefore also produce crystals at a physiological pH when they are mixed with betamethasone sodium phosphate. Thus, the potential risk should be noted for their use in interventions, such as epidural steroid injections.

Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil

The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km² and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1) a climate with an important water deficit and poverty in Ca2+ in both superficial and phreatic waters; and (2) an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.

O Pantanal da Nhecolândia é o maior e mais diversificado campo de lagos da região tropical do planeta, com cerca de 10.000 lagos de variadas salinidade, pH, alcalinidade, cor, fisiografia e atividade biológica dispostos em uma área de 24.000 km². Os lagos hipossalinos têm pH variável, baixa alcalinidade, macrófitas e baixa densidade de fitoplâncton. Os lagos salinos tem pH acima de 9 ou 10, elevada alcalinidade, alta densidade de fitoplâncton e praias de areia. A causa da diversidade desses lagos é uma questão ainda em aberto que é abordada nesta pesquisa. Propõe-se como principal causa um processo híbrido, geoquímico e biológico, baseado em (1) clima com um déficit hídrico importante e pobreza em Ca2+na água superficial e do freático e (2) na elevação do pH durante florações de cianobactérias. Estes dois aspectos desestabilizam a tendência geral de pH neutro para as águas superficiais da Terra. Este desequilíbrio resulta em aumento do pH e dissolução da areia quartzosa do fundo dos lagos salino-alcalinos. Durante secas extremas há precipitação de sílica amorfa nos espaços inter-granulares dos sedimentos de fundo destes lagos, aumentando seu isolamento do freático. O artigo discute este processo biogeoquímico, à luz de dados físico-químicos, químicos, fitoplânctonicos e de altimetria de precisão.

Análise da formação de carbonato de cálcio pela reação do hidróxido de cálcio com diferentes veículos anestésicos / Analysis of calcium carbonate formation from the reaction of calcium hydroxide with different anesthetic vehicles

Objetivo: Avaliar in vitro a formação de carbonato de cálcio (CaCO3) nas pastas de hidróxido de cálcio e seu pH, utilizando cinco veículos diferentes.Método: Foi utilizado o hidróxido de cálcio pró-análise e como veículos os anestésicos Septodont (mepivacaína 3% sem vasoconstritor), Mepiadre (mepivacaína 2% com epinefrina 1:100.000), Alphacaine (lidocaína 2% com epinefrina 1:100.000) e Novocol (lidocaína a 2% com fenilefrina 1:2.500) e água destilada milliQ (Millipore) como controle. Ependorfes com hidróxido de cálcio (0,8g) foram misturados em agitador (Phoenix AP 56) com os solventes (0,8 mL) até obtenção de uma pasta homogênea e armazenados (37 ºC±1). Cada solução anestésica constituiu um grupo analisado em três períodos de tempo: inicio, sete e quatorze dias (n=9). A quantidade de (CaCO3) foi determinada através de titulometria (0,1N de H2SO4) e o pH das soluções anestésicas e das pastas aferidos através de phmetro (Micronal). Análise de variância (ANOVA) e comparações múltiplas com Schefee foram empregados para verificar o comportamento dos valores obtidos entre os tempos testados para cada grupo e entre os grupos entre si nos períodos de tempo.Resultados: O pH das pastas ficou entre 12,46 e 12,88 imediatamente após a mistura. O grupo controle apresentou um maior percentual de formação de CaCO3 aos 14 dias de armazenamento enquanto que Novocol e Alphacaine maior formação nos tempos iniciais e 7 dias. Os demais grupos (Scandicaine e Mepiadre) não apresentaram diferenças estatisticamente significante entre os períodos de tempo avaliados. No entanto, entre os grupos no mesmo período de tempo, apenas aos 7 dias foi possível observação de alteração estatisticamente significativa no anestésico Novocol. Conclusão: O pH das pastas se mostrou elevado (entre 12.46 e 12.88), imediatamente após a mistura e que houve a formação de (CaCO3) nas pastas de hidróxido de cálcio independente do veículo empregado.

The Effects of the Alkalinization of Intracuff Lidocaine after Nitrous Oxide Anesthesia / 대한마취과학회지

BACKGROUND: Diffusion of nitrous oxide into the cuff of the endotracheal tube (ETT) results in an increase in cuff pressure. This method was used to test whether tracheal morbidity is related to fill the cuff of the endotracheal tube with alkalinized lidocaine instead of air or lidocaine only. METHODS: Adult patients scheduled for total thyroidectomy surgery were randomly enrolled (n = 30 for each group).The ETT cuff was filled with air 6 ml (Group C), with 2% lidocaine 6 ml (Group L), or with alkalinized lidocaine (4 ml or 2 ml of 2% lidocaine) using 2 ml (Group A) or 4 ml (Group B) of 8.4% NaHCO3.After tracheal extubation, sore throat was evaluated by visual analog scale as the main end-point of the study. RESULTS: Compared with group air or lidocaine only, the alkalinized-lidocaine groups had a significant reduction in sore throat during the 24-h postoperative period (P < 0.001).The difference was not significant between the two alkalinized lidocaine groups. Cough before tracheal extubation, nausea, postoperative vomiting, dysphonia, and hoarseness after extubation were decreased in the alkalinized-lidocaine groups compared with Group C and L, and a better tolerance was recorded with alkalinized-lidocaine groups compared with Group C and L. CONCLUSIONS: We concluded that use of intracuff alkalinized lidocaine is an effective adjunct to endotracheal intubation instead of air or lidocaine only during nitrous oxide anesthesia, however there were no differences between two alkalinizations.

Is There Any Relationship Between Hematuria in Rhabdomyolysis and Renal Injury?

PURPOSE: In previous literature, urinalysis in rhabdomyolysis has been known to be positive for occult blood, but without overt hematuria. Recently, however, we have reported hematuria in patients with doxylamine overdose in association with rhabdomyolysis. We wanted to determine whether the hematuria resulted from the toxicity of doxylamine itself or from rhabdomyolysis, and further to investigate the relationship between hematuria, acute renal failure (ARF), and the presence of urine alkalinization. METHODS: The medical records of 167 patients diagnosed with rhabdomyolysis who were admitted to Kyung Hee Medical Center between 2000 and 2004 were retrospectively examined. Patients without laboratory results 3 times a day, patients with inaccurate records, and patients with diseases that could cause hematuria were excluded, leaving 79 patients for evaluation. The relationship between laboratory results, occurrences of ARF and urine alkalinization were compared and assessed. RESULTS: Hematuria was observed in 76 of 79 patients with rhabdomyolysis, irrespective to the cause of rhabdomyolysis. The percentage of dysmorphic RBC was 58% and MCV (mean corpuscular volume) was 76+/-15 fL found in hematuria. Urine alkalinization was not associated with the presence of hematuria. The laboratory results of ARF patients compared to those of non-ARF patients showed a significant difference in the average urine pH, and ARF with rhabdomyolysis was not associated with muscle enzyme levels but rather was associated with the duration of hematuria. CONCLUSION: Hematuria was found in patients with rhabdomyolysis irrespective of the cause of rhabdomyolysis. Therefore, hematuria is associated with rhabdomyolysis rather than doxylamine intoxication. The occurrence of hematuria in rhabdomyolysis is unrelated to urine alkalinization. The duration of hematuria in ARF group was significantly longer than in non-ARF group. It is therefore important to bear in mind the possibility that ARF will develop when hematuria lasts for a long time. Furthermore, we feel that additional prospective studies and investigations into the mechanism of hematuria in rhabdomyolysis should be done.

Protective Effect of Urinary Alkalinization on Gentamicin Nephrotoxicity in Rats

We investigated the effect of urinary alkalinization accomplished by intraperitoneal injection of sodium bicarbonate and acetazolamide on gentamicin nephrotoxicity in male Fisher 344rats. Forty rats (body weight 200-300g) were divided into four groups: control (gentamicin 20mg/kg, bid), high sodium load (gentamicin 20mg/kg, 25cc of saline, bid), low bicarbonate (gentamicin 20mg/kg, 25cc of sodium bicarbonate 100mEq/L, 2.5mg of Diamox, bid) and high bicarbonate (gentamicin 20mg/kg, 10cc of sodium bicarbonate 250mEq/L, 2.5mg of Diamox, bid) groups. All drugs and electrolyte solutions as mentioned above were administered intraperitoneally twice a day for seven days and changes in renal functions were studied. While salt loading failed to influence the severity of gentamicin nephrotoxicity, urinary alkalinization induced by bicarbonate and acetazolamide injection showed remarkable ameliorating effects on gentamicin nephrotoxicity. The high bicarbonate group exhibited more beneficial effects than the low bicarbonate group on gentamicin nephrotoxicity. So, urinary alkalinization seems to be an effective method for the prevention of gentamicin nephrotoxicity in rats.