The phenol red compound: A potential artifact in pharmacological induction of ferroptosis.

Phenol red (PR) is a commonly used compound in culture media as a pH indicator. However, it is unknown whether this compound can interfere with the pharmacological induction of ferroptosis. Here, using high-content live-cell imaging death analysis, we determined that the presence of PR in the culture medium preconditioned normal and tumor cells to ferroptosis induced by system xc- inhibition mediated by imidazole ketone erastin (IKE) or GPX4 blockade in response to RSL-3, but had no significant effects against treatment with the endoperoxide FINO2. Mechanistically, we revealed that PR decreases the levels of the antiferroptotic genes Slc7a11, Slc3a2, and Gpx4, while promoting the overexpression de Acls4, a key inducer of ferroptosis. Additionally, through superresolution analysis, we determined that the presence of PR mislocalizes the system xc- from the plasma membrane. Thus, our results show that the presence of PR in the culture medium can be a problematic artifact for the accurate interpretation of cell sensitivity to IKE or RSL-3-mediated ferroptosis induction.

Enterotoxigenic profiles and submerged and interface biofilms in Bacillus cereus group isolates from foods.

Biofilm formation by Bacillus cereus strains is now recognized as a systematic contamination mechanism in foods; the aim of this study was to evaluate the production of submerged and interface biofilms in strains of B. cereus group in different materials, the effect of dextrose, motility, the presence of genes related to biofilms and the enterotoxigenic profile of the strains. We determine biofilm production by safranin assay, motility on semi-solid medium, toxin gene profiling and genes related to biofilm production by PCR in B. cereus group isolated from food. In this study, we observe strains used a higher production of biofilms in PVC; in the BHI broth, no submerged biofilms were found compared to phenol red broth and phenol red broth supplemented with dextrose; no strains with the ces gene were found, the enterotoxin profile was the most common the profile that includes genes for the three enterotoxins. We observed a different distribution of tasA and sipW with the origin of isolation of the strain, being more frequent in the strains isolated from eggshell. The production and type of biofilms are differential according to the type of material and culture medium used.

Removal of Anionic and Cationic Dyes Present in Solution Using Biomass of Eichhornia crassipes as Bioadsorbent.

The discharge of large amounts of effluents contaminated with gentian violet (GV) and phenol red (PR) threatens aquatic flora and fauna as well as human health, which is why these effluents must be treated before being discarded. This study seeks the removal of dyes, using water lily (Eichhornia crassipes) as an adsorbent with different pretreatments. PR and GV were analyzed by a UV-visible spectrophotometer. Equilibrium experimental data showed that Freundlich is the best model to fit PR and SIPS for GV, showing that the adsorption process for both dyes was heterogeneous, favorable, chemical (for GV), and physical (for PR). The thermodynamic analysis for the adsorption process of both dyes depends directly on the increase in temperature and is carried out spontaneously. The Pseudo first Order (PFO) kinetic model for GV and PR is the best fit for the dyes having an adsorption capacity of 91 and 198 mg/g, respectively. The characterization of the materials demonstrated significant changes in the bands of lignin, cellulose, and hemicellulose, which indicates that the functional groups could participate in the capture of the dyes together with the electrostatic forces of the medium, from which it be concluded that the adsorption process is carried out by several mechanisms.

Chemical Analysis by LC-MS of Cannabis sativa Root Samples from Northeast Brazil and Evaluation of Antitussive and Expectorant Activities.

Cannabis sativa is a millenary medicinal plant. However, contrary to worldwide paradigm-shifting, countries like Brazil still prohibit C. sativa cultivation and its medicinal use, even though many populations use aerial parts and roots of this plant for healthcare. As such, the objective of this work was to identify substances in the samples of the C. sativa roots, tracing a correlation with antitussive and expectorant effects. Therefore, samples of C. sativa roots were donated by the Polícia Federal Brasileira, and its aqueous extract (AECsR) was prepared with subsequent lyophilization, to maintain the material stability. After that, the material was analyzed by LC-MS to observe its chemical profile. Four samples (AECsR-A, B, C, and D) were tested in animal models of citric acid-induced cough (0.4 M) and phenol red expectoration (500 mg/kg). Using LC-MS it was possible to identify 5 molecules in C. sativa roots: p-coumaroyltyramine, tetrahydrocannabinol-C4, feruoiltyramine, anhydrocanabisativine, and cannabisativine. In experimental protocols, male mice (Mus musculus) were treated with samples of AECsR at doses of 12.5, 25, or 50 mg/kg regardless of the pharmacological test. In these tests, all samples showed the potential to treat cough and promote fluid expectoration, differing only in the dose at which these effects were observed. Therefore, the data showed that the C. sativa roots of the Brazilian Northeast showed antitussive and expectorant effects, even with intense secondary metabolites' variation, which alters its potency, but not its effect. This highlights the importance of this medicinal plant for future therapy and corroborates to traditional use.

Colorimetric loop-mediated isothermal amplification (LAMP) for cost-effective and quantitative detection of SARS-CoV-2: the change in color in LAMP-based assays quantitatively correlates with viral copy number.

We demonstrate a loop-mediated isothermal amplification (LAMP) method to detect and amplify SARS-CoV-2 genetic sequences using a set of in-house designed initiators that target regions encoding the N protein. We were able to detect and amplify SARS-CoV-2 nucleic acids in the range of 62 to 2 × 105 DNA copies by this straightforward method. Using synthetic SARS-CoV-2 samples and RNA extracts from patients, we demonstrate that colorimetric LAMP is a quantitative method comparable in diagnostic performance to RT-qPCR (i.e., sensitivity of 92.85% and specificity of 81.25% in a set of 44 RNA extracts from patients analyzed in a hospital setting).

Analytical and pharmacological validation of the quantification of phenol red in a mouse model: An optimized method to evaluate expectorant drugs.

INTRODUCTION: The evaluation of expectorant activity has been extensively studied in murine models, involving the secretion of phenol red in the trachea or bronchus to estimate the secretory capacity of lower airway mucosa. However, differences in the experimental protocols of several studies evidenced the need of to standardize the quantification of phenol red in the bronchoalveolar fluid (BALF). METHODS: The analytical methodology for the quantification of phenol red in the BALF was optimized by investigation of pH influence, quantity of the alkali agent added and appropriate wavelength for quantification of phenol red by UV-VIS spectroscopy. Different phenol red suspensions (0.05, 0.5, 1.25, 2.5 and 5%) were prepared and administered intraperitoneally in mice at doses 5, 25, 50, 250 or 500 mg/kg. RESULTS: It was shown that phenol red should be used at dose 500 mg/kg and intraperitoneal administration should be performed from a suspension at 1.25% (w/v). Furthermore, the alkalinizing agent of choice would be NaOH (0.1 M). The pharmacological validation of the analytical method showed that ambroxol (30, 60 or 120 mg/kg), guaifenesin (100 mg/kg), NH4Cl (2000 mg/kg) or salbutamol (4 mg/kg) can be used as positive controls. DISCUSSION: The phenol red quantification in the BALF is a rapid and low cost assay for the discovery of new expectorant drugs. Thus, it was proposed a standardization of the analytical and pharmacological methods to ensure the reliability of BALF processing and reproducibility of phenol red quantification for data analysis.

Kinetic Evaluation of Dye Decolorization by Fenton Processes in the Presence of 3-Hydroxyanthranilic Acid.

The fungal metabolite 3-hydroxyanthranilic acid (3-HAA) was used as a redox mediatorwith the aim of increasing dye degradation by Fenton oxidative processes (Fe2+/H2O2, Fe3+/H2O2). ItsFe3+-reducing activity can enhance the generation of reactive oxygen species as HO● radicals.Initially, the influence of 3-HAA on decolorization kinetics of five dyes (methylene blue,chromotrope 2R, methyl orange, phenol red, and safranin T) was investigated using decolorizationdata from a previous work conducted by the present research group. Fe3+-containing reaction datawere well fitted with first-order and mainly second-order kinetic models, whereas the BMG(Behnajady, Modirshahla and Ghanbary) model obtained optimal fit to Fe2+. Improvements inkinetic parameters (i.e., apparent rate constants and maximum oxidation capacity) were observedwith the addition of 3-HAA. In another set of experiments, a decrease in apparent activation energywas observed due to introducing 3-HAA into reactions containing either Fe2+ or Fe3+ in order todecolorize phenol red at different temperatures. This indicates that the redox mediator decreasesthe energy barrier so as to allow reactions to occur. Thus, based on recent experiments and thereaction kinetics models evaluated herein, pro-oxidant properties have been observed for 3-HAAin Fenton processes.

Evaluation of tear production in juvenile opossum using three different methods / Avaliação da produção lacrimal em gambás filhotes por três diferentes métodos

The establishment of parameters for tear production in different species is important for better understanding eye´s health and is one of the components of the ophthalmic semiological technique. Particularities derived from the anatomophysiology of non-domestic species induce the search for more reliable methodologies. The aim was to evaluate and compare tear production of white-eared opossum (Didelphis albiventris) and Brazilian common opossum (Didelphis aurita) by three different methods. Fifteen individuals of each species, juveniles, healthy, of both sexes, with 60 to 90 days of life, were physically restrained. Phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT) and modified -Schirmer tear test (mSTT) were performed. PRTT was the most difficult to perform because of the wire malleability, while EAPPTT was more feasible for both species. The median ± semi-quartile range for PRTT were 19.79±2.61mm/15 "and 5.22±2.92mm/15", for EAPPTT were 16.25±1.82mm/min and 10.9±3.04mm/min, and for STTm were 0±1.63mm/min and 0±1.63mm/min for white-eared opossum and Brazilian common opossum respectively. There was no difference between the right and left eye neither sex. A significant difference was obtained for the same test to different species. No significant correlation was found between the tests for both species. The description of tear production parameters for juvenile white-eared opossum and Brazilian common opossum may be used as a tool, which will allow the early diagnosis of ocular diseases.(AU)

O estabelecimento do parâmetro de produção lacrimal nas diferentes espécies é importante para o entendimento da saúde do olho e é um dos componentes da semiotécnica oftálmica. Particularidades derivadas da anatomofisiologia das espécies não domésticas induzem a busca de metodologias que sejam mais fidedignas aos parâmetros. Objetivou-se com este estudo avaliar e comparar a produção lacrimal de gambás-de-orelha-branca (Didelphis albiventris) e gambás-de-orelha-preta (Didelphis aurita) por três diferentes métodos. Quinze indivíduos de cada espécie, juvenis, hígidos, de ambos os sexos, com 60 a 90 dias de vida, foram contidos fisicamente para realização do teste lacrimal do vermelho de fenol (TLVF), da ponta de papel absorvente estéril e do teste lacrimal de Schirmer modificado (TLSm). O TLVF foi o mais difícil de ser executado devido à maleabilidade do fio, enquanto a TEPA se mostrou mais exequível para ambas as espécies. A mediana ± intervalo semi-interquartil para o TLVF foi de 19,79±2,61mm/15" e 5,22±2,92mm/15", para a TEPA foram de 16,25±1,82mm/min e 10,93±3,04mm/min, e para o TLSm foram de 0±1,63mm/min e 0±1,63mm/min, para gambás-de-orelha-branca e gambás-de-orelha-preta, respectivamente. Não houve diferença entre o olho direito e esquerdo e nem quanto ao sexo. Obteve-se diferença significativa para um mesmo teste entre as espécies. Não foi encontrada correlação significativa entre os testes para ambas as espécies. A quantificação da porção aquosa da lágrima poderá auxiliar no diagnóstico precoce de doenças oculares nas espécies estudadas.(AU)

Evaluation of tear production in juvenile opossum using three different methods / Avaliação da produção lacrimal em gambás filhotes por três diferentes métodos

The establishment of parameters for tear production in different species is important for better understanding eye´s health and is one of the components of the ophthalmic semiological technique. Particularities derived from the anatomophysiology of non-domestic species induce the search for more reliable methodologies. The aim was to evaluate and compare tear production of white-eared opossum (Didelphis albiventris) and Brazilian common opossum (Didelphis aurita) by three different methods. Fifteen individuals of each species, juveniles, healthy, of both sexes, with 60 to 90 days of life, were physically restrained. Phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT) and modified -Schirmer tear test (mSTT) were performed. PRTT was the most difficult to perform because of the wire malleability, while EAPPTT was more feasible for both species. The median ± semi-quartile range for PRTT were 19.79±2.61mm/15 "and 5.22±2.92mm/15", for EAPPTT were 16.25±1.82mm/min and 10.9±3.04mm/min, and for STTm were 0±1.63mm/min and 0±1.63mm/min for white-eared opossum and Brazilian common opossum respectively. There was no difference between the right and left eye neither sex. A significant difference was obtained for the same test to different species. No significant correlation was found between the tests for both species. The description of tear production parameters for juvenile white-eared opossum and Brazilian common opossum may be used as a tool, which will allow the early diagnosis of ocular diseases.(AU)

O estabelecimento do parâmetro de produção lacrimal nas diferentes espécies é importante para o entendimento da saúde do olho e é um dos componentes da semiotécnica oftálmica. Particularidades derivadas da anatomofisiologia das espécies não domésticas induzem a busca de metodologias que sejam mais fidedignas aos parâmetros. Objetivou-se com este estudo avaliar e comparar a produção lacrimal de gambás-de-orelha-branca (Didelphis albiventris) e gambás-de-orelha-preta (Didelphis aurita) por três diferentes métodos. Quinze indivíduos de cada espécie, juvenis, hígidos, de ambos os sexos, com 60 a 90 dias de vida, foram contidos fisicamente para realização do teste lacrimal do vermelho de fenol (TLVF), da ponta de papel absorvente estéril e do teste lacrimal de Schirmer modificado (TLSm). O TLVF foi o mais difícil de ser executado devido à maleabilidade do fio, enquanto a TEPA se mostrou mais exequível para ambas as espécies. A mediana ± intervalo semi-interquartil para o TLVF foi de 19,79±2,61mm/15" e 5,22±2,92mm/15", para a TEPA foram de 16,25±1,82mm/min e 10,93±3,04mm/min, e para o TLSm foram de 0±1,63mm/min e 0±1,63mm/min, para gambás-de-orelha-branca e gambás-de-orelha-preta, respectivamente. Não houve diferença entre o olho direito e esquerdo e nem quanto ao sexo. Obteve-se diferença significativa para um mesmo teste entre as espécies. Não foi encontrada correlação significativa entre os testes para ambas as espécies. A quantificação da porção aquosa da lágrima poderá auxiliar no diagnóstico precoce de doenças oculares nas espécies estudadas.(AU)

Schirmer's I, modified Schirmer's I, phenol red thread, and paper point tests: a comparative study for tear production measurement techniques in broiler chicks (Gallus gallus domesticus).

Problems with indoor husbandry and immunological challenges are some of the stressors that broilers may face which can affect production. Infectious diseases can compound the effects of excessive concentrations of ammonia causing respiratory and ocular inflammation and increased lacrimal production in broiler chickens. The objectives of this investigation were to establish normal values of tear production in chicks and compare the practicality of the different methods. Palpebral fissure length (PFL) and tear production were evaluated in Cobb 500 chicks at 5 d old and then at 5 d of age by the following methods: modified Schirmer's test I (mSTT1), phenol red cotton thread tear test (PRCTTT), and standardized endodontic absorbent paper point test (EAPPTT). Ten chicks at the age of 5 and 42 d were evaluated for each method. In addition, at 42 d, when the palpebral fissure permitted, a regular-sized Schirmer tear test I (STT1) was performed in another group of 10 chickens. Overall, PFL and the secretion of the aqueous phase of the tear film increased with age. Mean mSTT1 results were 5.00 ± 1.83 mm and 10.45 ± 2.58 mm for 5- and 42-d-old chicks, respectively. Mean PRCTTT results were 12.37 ± 1.80 mm and 25.58 ± 4.8 mm for 5- and 42-d-old chicks, respectively. Mean EAPPTT results were 7.13 ± 0.72 mm and 12.03 ± 0.92 mm for 5- and 42-d-old chicks, respectively. Mean STT1 for 42-d-old chicks was 11.40 ± 2.60 mm. Results obtained with endodontic paper points showed the lowest coefficient of variation and investigators found the test easier to perform. These values reported for broilers at different ages may be applied in poultry ophthalmology to help the diagnosis of lacrimal production disorders and to detect early disease symptoms that could cause economic losses in poultry production.

[Rapid test for detection of susceptibility to cefotaxime in Enterobacteriaceae]. / Método rápido para la detección de la sensibilidad a cefotaxima en enterobacterias.

In this work an "in house" rapid test based on the change in pH that is due to hydrolysis for detecting Enterobacteriaceae susceptible to cefotaxime is evaluated. The strains of Enterobacteriaceae from 1947 urine cultures were assessed using MicroScan panels and the "in house" test. This rapid test includes red phenol solution and cefotaxime. Using MicroScan panels, 499 Enterobacteriaceae isolates were evaluated, which included 27 isolates of Escherichia coli producing extended-spectrum beta-lactamases (ESBL), 16 isolates of Klebsiella pneumoniae ESBL and 1 isolate of Klebsiella oxytoca ESBL. The "in house" test offers the following values: sensitivity 98% and specificity 97%, with negative predictive value 100% and positive predictive value 78%. The "in house" test based on the change of pH is useful in our area for detecting presumptively cefotaxime-resistant Enterobacteriaceae strains.

Método rápido para la detección de la sensibilidad a cefotaxima en enterobacterias / Rapid test for detection of susceptibility to cefotaxime in Enterobacteriaceae

En este trabajo se evalúa una prueba rápida in house para la detección de enterobacterias sensibles a cefotaxima, basada en el cambio de pH del rojo fenol debido a la hidrólisis de este antibiótico. Las cepas de enterobacterias procedentes de 1.947 urocultivos se evaluaron mediante los paneles MicroScan y esta prueba in house. Mediante los paneles de MicroScan se estudiaron 499 aislados de enterobacterias, entre los cuales había 27 aislados de Escherichia coli productora de β-lactamasa de espectro extendido (BLEE), 16 de Klebsiella pneumoniae BLEE y una de Klebsiella oxytoca BLEE. La prueba in house mostró una sensibilidad del 98% y una especificidad del 97%, con un valor predictivo negativo del 100% y un valor predictivo positivo del 78%. La prueba in house basada en el cambio de pH es útil en nuestro medio para detectar presuntivamente de forma rápida cepas de enterobacterias con cierta resistencia a cefotaxima.

In this work an "in house" rapid test based on the change in pH that is due to hydrolysis for detecting Enterobacteriaceae susceptible to cefotaxime is evaluated. The strains of Enterobacteriaceae from 1947 urine cultures were assessed using MicroScan panels and the "in house" test. This rapid test includes red phenol solution and cefotaxime. Using MicroScan panels, 499 Enterobacteriaceae isolates were evaluated, which included 27 isolates of Escherichia coli producing extended-spectrum beta-lactamases (ESBL), 16 isolates of Klebsiella pneumoniae ESBL and 1 isolate of Klebsiella oxytoca ESBL. The "in house" test offers the following values: sensitivity 98% and specificity 97%, with negative predictive value 100% and positive predictive value 78%. The "in house" test based on the change of pH is useful in our area for detecting presumptively cefotaxime-resistant Enterobacteriaceae strains.

Detrimental Effect of Phenol Red on the Vitrification of Cat (Felis catus) Ovarian Tissue.

The aim of this study was to investigate the effects of different media with or without phenol red or the antioxidant trolox on the successful vitrification of feline ovarian tissue. In a first experiment, ovarian cortical pieces from three cats were vitrified in solutions of Roswell Park Memorial Institute (RPMI)-1640 medium, Minimum Essential Medium, Dulbecco's modified Eagle's medium, or Tissue Culture Medium 199 as basic medium, supplemented or not with 50 µM of trolox, all containing 40% ethylene glycol (EG) and 1 M of sucrose. RPMI-1640 (phenol red-free) without trolox was the only medium that preserved the percentage of morphologically normal preantral follicles similar to control (80%). The main difference between RPMI-1640 and the other media was the absence of phenol red and CaCl2. In a second experiment, ovarian cortical pieces from three cats were vitrified in a solution containing RPMI-1640 as basic medium, 40% EG, 1 M of sucrose, supplemented or not with phenol red or CaCl2 alone, or in combination. It was observed that phenol red supplementation led to follicular degeneration. Finally, to evaluate the interaction between phenol red and the cryoprotectant agent (i.e., EG), ovarian tissue was exposed to RPMI-1640 supplemented with phenol red and EG at different concentrations (10%, 20%, or 40%). There was an inverse relationship between EG concentration and free phenol red in the medium after exposure. It is suggested that vitrification of feline ovarian tissue should be performed in a phenol red-free medium. Medium supplementation with 50 µM of trolox was deleterious for follicular morphology.

Adequacy of Petrifilm™ Aerobic Count plates supplemented with de Man, Rogosa & Sharpe broth and chlorophenol red for enumeration of lactic acid bacteria in salami.

The present study aimed to assess the performance of alternative protocols to enumerate lactic acid bacteria (LAB) in salami. Fourteen cultures and two mixed starter cultures were plated using six protocols: 1) Petrifilm™ Aerobic Count (AC) with MRS broth and chlorophenol red (CR), incubated under aerobiosis or 2) under anaerobiosis, 3) MRS agar with CR, 4) MRS agar with bromocresol purple, 5) MRS agar at pH5.7, and 6) All Purpose Tween agar. Samples of salami were obtained and the LAB microbiota was enumerated by plating according protocols 1, 2, 3 and 5. Regression analysis showed a significant correlation between the tested protocols, based on culture counts (p<0.05). Similar results were observed for salami, and no significant differences of mean LAB counts between selected protocols (ANOVA, p>0.05). Colonies were confirmed as LAB, indicating proper selectivity of the protocols. The results showed the adequacy of Petrifilm™ AC supplemented with CR for the enumeration of LAB in salami.

Evaluation of standardized endodontic paper point tear test in New Zealand white rabbits and comparison between corneal sensitivity followed tear tests.

OBJECTIVE: To evaluate endodontic paper point tear test (PPTT) in rabbits and compare changes in corneal touch threshold (CTT) induced by Schirmer tear test (STT) and PPTT. Normal corneal sensitivity recovery time after both tear tests was also measured. Also, mean PPTT and STT values were obtained. METHODS: Tear production of 20 eyes, from 10 rabbits, was evaluated using STT and the PPTT. Central corneal touch threshold was measured by a Cochet-Bonnet esthesiometer before any tear test was performed (zero time), immediately after the test (1 min), and consecutively at 6, 11, 16, and 26 min. Tests were conducted on three consecutive days: Day 1 - control condition, no tear tests performed only the CTT; Day 2 - CTT before and after PPTT; and Day 3 - CTT before and after STT. CTT values were compared using repeated measures ANOVA. RESULTS: Corneal touch threshold was significantly increased for at least 16 min after STT, indicating STT causes corneal discomfort. No difference was found between CTT following PPTT and controls, indicating PPTT caused minimal corneal discomfort. The mean (±SD) value for STT was 5.2 ± 1.0 mm/min and for PPTT was 13.8 ± 1.5 mm/min. DISCUSSION: The aqueous fraction of rabbit's tears can be successfully measured by PPTT. This report established reference values for PPTT in rabbits. Additionally, the absence of a significant difference in CTT after PPTT compared with controls shows that PPTT is well tolerated by rabbits. Considering the improved comfort (compared with STT), accuracy, and low cost, PPTT is a bona fide method of measuring aqueous tear production in rabbits.

Evidence for the involvement of peripheral ß-adrenoceptors in delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats.

Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg-1·day-1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean ± SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7 ± 1.6 vs 47.1 ± 2.3%) and of At (33.2 ± 2.3 vs 54.7 ± 3.6%) on GE and significantly reduced the effect of AA (48.1 ± 3.2 vs 67.2 ± 3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean ± SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1 ± 1.7 vs 46.9 ± 2.7%) and At (30.5 ± 1.7 vs 49 ± 3.2%) and significantly reduced the effect of AA (48.4 ± 2.6 vs 59.5 ± 3.1%). These data suggest activation of peripheral ß-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.

Evidence for the involvement of peripheral -adrenoceptors in delayed liquid gastric emptying induced by dipyrone, 4-aminoantipyrine, and antipyrine in rats

Dipyrone (Dp), 4-aminoantipyrine (AA), and antipyrine (At) delay liquid gastric emptying (GE) in rats. We evaluated adrenergic participation in this phenomenon in a study in male Wistar rats (250-300 g) pretreated subcutaneously with guanethidine (GUA), 100 mg·kg−1·day−1, or vehicle (V) for 2 days before experimental treatments. Other groups of animals were pretreated intravenously (iv) 15 min before treatment with V, prazosin (PRA; 1 mg/kg), yohimbine (YOH; 3 mg/kg), or propranolol (PRO; 4 mg/kg), or with intracerebroventricular (icv) administration of 25 µg PRO or V. The groups were treated iv with saline or with 240 µmol/kg Dp, AA, or At. GE was determined 10 min later by measuring the percentage of gastric retention (%GR) of saline labeled with phenol red 10 min after gavage. %GR (mean±SE, n=8) indicated that GUA abolished the effect of Dp (GUA vs V=31.7±1.6 vs 47.1±2.3%) and of At (33.2±2.3 vs 54.7±3.6%) on GE and significantly reduced the effect of AA (48.1±3.2 vs 67.2±3.1%). PRA and YOH did not modify the effect of the drugs. %GR (mean±SE, n=8) indicated that iv, but not icv, PRO abolished the effect of Dp (PRO vs V=29.1±1.7 vs 46.9±2.7%) and At (30.5±1.7 vs 49±3.2%) and significantly reduced the effect of AA (48.4±2.6 vs 59.5±3.1%). These data suggest activation of peripheral β-adrenoceptors in the delayed GE induced by phenylpyrazolone derivatives.

Chromoendoscopy with red phenol in the diagnosis of Helicobacter pylori infection.

An analytic study to validate a diagnostic test was carried out at the Institute of Gastroenterology in Havana, Cuba in adult patients of both sexes in whom chromoendoscopy was carried out with red phenol at 0.1% over the gastric mucosa for the detection of Helicobacter pylori infection between November 2008 and December 2010. The staining with red phenol at 0.1% is included in the invasive tests for the diagnosis of Helicobacter pylori infection and of the reactive techniques. The sensibility of red phenol dye in the diagnosis of Helicobacter pylori infection in the patients studied was of 72.6% with a confidence interval (C.I.) of 95% (64.9 to 79.2%) and a specificity of 75.5% C.I. 95% (61.9 to 85.4%). The positive predictive value was of 89.8% C.I. 95% (83.1 to 94.1%) and the negative predictive value of 48.1% C.I. 95% (37.3 to 59.0%). The proportion of false positives was of 24.5% C.I. 95% (14.6 to 38.1%)and the proportion of false negatives was of 27.4% C.I. 95% (20.8 to 35.1%). The diagnostic accuracy of the dye on the patients studied was 73.3% C.I. 95% (66.7 to 79.0%). The diagnostic odds ratio was 8.17 C.I. 95% (3.88 to 17.23), the J Youden ratio of 0.5 and the Kappa coefficient of 0.40 C.I. 95% (0.27 to 0.54). The staining dye with red phenol at 0.1% resulted in a useful method in the diagnosis of Helicobacter pylori infection in the gastric mucosa, it can be applied in our environment and has multiple advantages (topographic localization, avoids contamination and fast and immediate reading).

Experimental correlation between the pKa value of sulfonphthaleins with the nature of the substituents groups.

This work presents the results obtained from a spectrophotometry study performed on some indicators of the sulfonphtaleins like phenol red (PR), thymol blue (TB), bromothymol blue (BTB), xylenol orange (XO) and methylthymol blue (MTB). During the first stage the acidity constants of some of the indicators were determined using the data from spectrophotometry, potentiometry and with the use of the software SQUAD. These were as follows: for the equilibrium 2H+BTB<-->H(2)BTB, log beta(2)=15.069+/-0.046 and for H+BTB<-->HBTB, log beta(1)=8.311+/-0.044. For the XO and the MTB five values were calculated for each, namely, for MTB: log beta(5)=42.035, log beta(4)=38.567+/-0.058, log beta(3)=32.257+/-0.057, log beta(2)=23.785+/-0.057, and log beta(1)=12.974+/-0.045 while for XO: log beta(5)=40.120+/-0.102, log beta(4)=35.158+/-0.062, log beta(3)=29.102+/-0.053, log beta(2)=21.237+/-0.044, and log beta(1)=11.682+/-0.044. During the second stage, a study was conducted on the effect of the substituents present in the indicators to determine the effect of different functional groups on the pK(a) value corresponding to the last indicator's dissociation.