After myringotomy, can topical Mesna application be an alternative method to ventilation tube application?

Sodium-2-mercaptoethanesulfonate (Mesna) is a mucolytic substance that is also used for chemically assisted tissue dissection in otological surgery. We investigated the effects of Mesna as a chemical agent on the closing time of perforation of the eardrum in an experimental animal model. We performed simple myringotomy with a knife on 44 tympanic membranes of 22 rats. Four rats were excluded from the study because of serosity in their ears. Rats were divided into two study groups and a control group. These groups were the Mesna-administered group (Group A) (8 rats, 15 tympanic membranes), the saline-administered group (Group B) (8 rats, 14 tympanic membranes) and the control (native) group (6 rats, 11 tympanic membranes) (Group C). We applied Mesna locally for 20 min following myringotomy. Examination was made with an otoendoscope on days 1, 2, 3, 5, and 7, and patency rates were recorded. According to our results, we found that the closing time of the tympanic membrane was significantly longer in the Mesna group than in the saline administrated and native group. After myringotomy procedure, the application of a single dose of Mesna may contribute to the recovery duration of middle-ear pathologies by delaying the closing time of tympanic membrane perforation. However, Mesna cannot be an alternative method for the application of ventilation tubes.

A comparative study on daily evapotranspiration estimation by using various artificial intelligence techniques and traditional regression calculations.

Evapotranspiration is an important parameter to be considered in hydrology. In the design of water structures, accurate estimation of the amount of evapotranspiration allows for safer designs. Thus, maximum efficiency can be obtained from the structure. In order to accurately estimate evapotranspiration, the parameters affecting evapotranspiration should be well known. There are many factors that affect evapotranspiration. Some of these can be listed as temperature, humidity in the atmosphere, wind speed, pressure and water depth. In this study, models were created for the estimation of the daily evapotranspiration amount by using the simple membership functions and fuzzy rules generation technique (fuzzy-SMRGT), multivariate regression (MR), artificial neural networks (ANNs), adaptive neuro-fuzzy inference system (ANFIS) and support vector regression (SMOReg) methods. Model results were compared with each other and traditional regression calculations. The ET amount was calculated empirically using the Penman-Monteith (PM) method which was taken as a reference equation. In the created models, daily air temperature (T), wind speed (WS), solar radiation (SR), relative humidity (H) and evapotranspiration (ET) data were obtained from the station near Lake Lewisville (Texas, USA). The coefficient of determination (R2), root mean square error (RMSE) and average percentage error (APE) were used to compare the model results. According to the performance criteria, the best model was obtained by Q-MR (quadratic-MR), ANFIS and ANN methods. The R2, RMSE, APE values of the best models were 0,991, 0,213, 18,881% for Q-MR; 0,996; 0,103; 4,340% for ANFIS and 0,998; 0,075; 3,361% for ANN, respectively. The Q-MR, ANFIS and ANN models had slightly better performance than the MLR, P-MR and SMOReg models.

Effect of nonsteroidal anti-inflammatory drugs on colorectal distension-induced visceral pain.

OBJECTIVES: To investigate nonsteroidal anti-inflammatory drugs effectiveness in colorectal distension (CRD)-induced visceral pain model. MATERIALS AND METHODS: Male Sprague-Dawley (250-300 g) rats were anesthetized with ketamine (50 mg/kg, intraperitoneally [i.p.]) and chlorpromazine (25 mg/kg, i.p.). Two bipolar Teflon-coated Ni/Cr wire electrodes (80-M diameter) were placed in the abdominal external oblique muscle for the recording of electromyography. Jugular vein catheter was placed for the administration of drugs. CRD method was applied to evaluate of visceral pain. All drugs (paracetamol, meloxicam, metamizole, and dexketoprofen) administered intravenously. RESULTS: Paracetamol 200, 400, and 600 mg/kg did not change the visceromotor response (VMR) when compare with the control group. Meloxicam 2 and 4 mg/kg showed no effect but at doses of 6 mg/kg meloxicam significantly ([51.9 ± 6.4%] [P < 0.001]) decreased VMR compared with the control group. Metamizole 200 mg/kg did not change responses but dose of 400 and 600 mg/kg metamizole reduced VMR. Dexketoprofen 2 and 4 mg/kg did not cause a change in VMR but 6 mg/kg dose significantly reduced response compared with the control group ([43.9 ± 3.9%, 36.8 ± 2.8%, 34.8 ± 2.5%, 42.1 ± 4.8%, 40.7 ± 3.5%, 36.4 ± 2.7%, and 26.1 ± 2.2%]; from 10 min to 70 min, respectively, [P < 0.05]). CONCLUSION: Metamizole, dexketoprofen and meloxicam show antinociceptive effect with different duration of action on CRD-induced visceral pain model. This condition can be explained due to different chemical structures and different mechanisms which play a role in modulation of pain.

The false-positive responses of analgesic drugs to the intradermal serotonin- and compound 48/80-induced scratches as an animal model of itch.

Intradermal injection of pruritogens such as serotonin, histamine and compound 48/80 into the skin and then, the evaluation of the scratching behavior is the commonly used animal model to advance pruritic research and drug development. However, predictive validity of this model is poorly documented. There is a close interaction between itch and pain sensations with regard to mediation through an anatomically and functionally identical neuronal pathway. One approach is whether the existing animal model of itch differentiates itch or pain to show efficacy of clinically effective analgesic drugs as a back translation. In this study, we explored the effects of different group of analgesic drugs on serotonin and compound 48/80-induced scratching behavior in Balb-C mice. Serotonin (25 µg) and compound 48/80 (100 µg) was injected intradermally in a volume of 50 µl into the rostral part of skin on the back of male mice and scratches were counted for a 30-min observation period. Morphine (1, 3, 10 mg/kg), tramadol (20, 40, 80 mg/kg), cannabinoid agonist CP 55,940 (0.1, 0.3, 1 mg/kg), paracetamol (100, 200, 300 mg/kg) and diclofenac (50, 100, 200 mg/kg) were given intraperitoneally 30 min prior to pruritogen injection. The analgesic drugs dose dependently blocked serotonin and compound 48/80-induced straching behavior with exerting complete inhibition at certain doses. Our data suggests that intradermal pruritogen-induced scratching models may not discriminate pain and itch sensations and give false positive results when standard analgesic drugs are used.

Can empirical hypertonic saline or sodium bicarbonate treatment prevent the development of cardiotoxicity during serious amitriptyline poisoning? Experimental research.

OBJECTIVE: The aim of this experimental study was to investigate whether hypertonic saline or sodium bicarbonate administration prevented the development of cardiotoxicity in rats that received toxic doses of amitriptyline. METHOD: Thirty-six Sprague Dawley rats were used in the study. The animals were divided into six groups. Group 1 received toxic doses of i.p. amitriptyline. Groups 2 and 3 toxic doses of i.p. amitriptyline, plus i.v. sodium bicarbonate and i.v. hypertonic saline, respectively. Group 4 received only i.v. sodium bicarbonate, group 5 received only i.v. hypertonic saline, and group 6 was the control. Electrocardiography was recorded in all rats for a maximum of 60 minutes. Blood samples were obtained to measure the serum levels of sodium and ionised calcium. RESULTS: The survival time was shorter in group 1. In this group, the animals' heart rates also decreased over time, and their QRS and QTc intervals were significantly prolonged. Groups 2 and 3 showed less severe changes in their ECGs and the rats survived for a longer period. The effects of sodium bicarbonate or hypertonic saline treatments on reducing the development of cardiotoxicity were similar. The serum sodium levels decreased in all the amitriptyline-applied groups. Reduction of serum sodium level was most pronounced in group 1. CONCLUSION: Empirical treatment with sodium bicarbonate or hypertonic saline can reduce the development of cardiotoxicity during amitriptyline intoxication. As hypertonic saline has no adverse effects on drug elimination, it should be considered as an alternative to sodium bicarbonate therapy.