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.

New insights on the adsorption of phenol red dyes from synthetic wastewater using activated carbon/Fe2(MoO4)3.

Water shortage is considered as one of the main challenges of human life. A practical solution to this problem is the wastewater treatment. The removal of dyes from wastewaters has received considerable critical attention by researchers due to their high volume and toxicity. In the current research, the adsorption of phenol red dyes from synthetic wastewater using the activated carbon produced from Mespilus germanica modified with Fe2(MoO4)3 was studied. The proposed adsorbent was characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX)/Map, Brunauer-Emmett-Teller (BET), and Raman techniques. The optimal adsorption operating parameters including pH, stirring rate, temperature, dosage of adsorbent, dye initial concentration, and contact time were 3, 500 rpm, 25 °C, 1 g/L, 10 mg/L, and 60 min, respectively. Furthermore, the successful regeneration of the adsorbent for 3 times, using methanol solution as a regeneration medium, denoted its capability in performing adsorption and desorption processes. Equilibrium studies showed that the adsorption of phenol red dyes by activated carbon (AC)/Fe2(MoO4)3 was desirable and physical and the experimental data were fitted well by the Freundlich model. In addition, the kinetic behavior of the current adsorption process was well described by the pseudo-second-order kinetic model, while thermodynamic calculations showed that the process was exothermic and spontaneous.

An Extensive Study of Phenol Red Thread as a Novel Non-Invasive Tear Sampling Technique for Proteomics Studies: Comparison with Two Commonly Used Methods.

Tear samples are considered in recent publications as easily, noninvasively collectible information sources for precision medicine. Their complex composition may aid the identification of biomarkers and the monitoring of the effectiveness of treatments for the eye and systemic diseases. Sample collection and processing are key steps in any analytical method, especially if subtle personal differences need to be detected. In this work, we evaluate the usability of a novel sample collection technique for human tear samples using phenol red threads (cotton thread treated with the pH indicator phenol red), which are efficiently used to measure tear volume in clinical diagnosis. The low invasiveness and low discomfort to the patients have already been demonstrated, but their applicability for proteomic sample collection has not yet been compared to other methods. We have shown, using various statistical approaches, the qualitative and quantitative differences in proteomic samples collected with this novel and two traditional methods using either glass capillaries or Schirmer's paper strips. In all parameters studied, the phenol red threads proved to be equally or even more suitable than traditional methods. Based on detectability using different sampling methods, we have classified proteins in tear samples.

Development of a Dye-Based Device to Assess Poultry Meat Spoilage. Part I: Building and Testing the Sensitive Array.

The rationale behind the material and dye selection and the investigation of the properties of a solid-phase sensor array designed for following chicken meat spoilage is presented, having in mind that the final target must be the naked eye identification of the degradation steps. The device is obtained by fixing five acid-base indicators, m-cresol purple (1), o-cresol red (2), bromothymol blue (3), thymol blue (4), and chlorophenol red (5), and a sensing molecule specific for thiols, 5,5'-dithiobis(2-nitrodibenzoic acid), called Ellman's reagent, (6) on a commercial cellulose-based support. The dimensions of the sensor and the amount of dye sorbed on the solid are carefully studied. The preparation protocol to get reproducible sensing materials is established, based on the kinetic study and the color change investigation. The material stability and the capacity of changing color, according to the acid-base properties of the dyes, are tested. The sources of uncertainty, coming from the technique employed for signal data acquisition and treatment and from the intrinsic variability of the spots based on the commercial support, are established. The highest variability does not come from photo acquisition by a mobile phone, the effect of the illumination equipment, the partial least-squares (PLS) model employed to assess the amount of dye sorbed into the solid but from the variability of different spots and was found equal to 10%. The uncertainty is adequate for final employment since it is referred to as replicates under different conditions that are definitively judged almost always identical by naked eye evaluation, which is our last target for assessing a change of the colors associated with spoilage.

Development of a Dye-Based Device to Assess the Poultry Meat Spoilage. Part II: Array on Act.

This work presents a colorimetric dye-based array for naked-eye detection of chicken meat spoilage. The array is obtained by fixing five acid-base indicators, m-cresol purple (1), o-cresol red (2), bromothymol blue (3), thymol blue (4), and chlorophenol red (5), and a sensing molecule specific for thiols, 5,5'-dithiobis(2-nitrodibenzoic acid), called Ellman's reagent (6), on a cellulose-based support. The dyes, being permanently charged, are fixed on the support via ion-exchange. The entire degradation process of beast poultry meat, at ambient temperature and in a domestic fridge, is followed by the change of the color of the array, placed in the headspace over the meat samples. The device is set after selection of the most suitable starting form, which could be the acidic or the basic color of indicators, being the proper dye concentration and the dimension of the spots already established. Basing on sensors colors, we identified three levels of the degradation process of chicken meat, named SAFE, WARNING, and HAZARD. By instrumental analysis, we demonstrated that sensors response was correlated to volatile organic compounds (VOCs) composition in the headspace and, thus, to meat spoilage progress. We demonstrated that biogenic amines (BAs), commonly considered a critical spoilage marker, are indeed produced into the samples but never present in the headspace, even in traces, during the investigated time-lapse. The VOC evolution nevertheless allows one to assign the sample as WARNING and further HAZARD. Some indicators turned out to be more informative than others, and the best candidates for a future industrial application resulted in a bromothymol blue (3)-, chlorophenol red (5)-, and Ellman's reagent (6)-based array.

Development of a RP-HPLC method for simultaneous determination of reference markers used for in-situ rat intestinal permeability studies.

One of the most common techniques for assessing the intestinal absorption characteristics of drugs is single-pass intestinal perfusion (SPIP) method. Metoprolol tartrate (MT, reference standard) and phenol red (PR, zero permeability marker) are the compounds that are normally used in SPIP studies. The aim of this study was to develop a reverse phase high-performance liquid chromatography (RP-HPLC) method combined with UV-detection for the simultaneous determination of MT and PR in the perfusion medium used in SPIP experiments. Elution was performed using a Restek Raptor C18 column (5 µm, 4.6 mm × 250) at a temperature of 25 °C. The mixture of the mobile phase consisted of (MeOH):(Phosphate buffer solution, PBS), (20 mM, pH 3.0 adjusted with ortho-phosphoric acid),(55:45, v/v). Flow rate and column temperature were set at 1.2 mL min-1 and 25 °C, respectively. MT and PR were injected as 20 µL into the HPLC system. UV detection was performed at 227 nm. The obtained retention times were reported as 2.89 and 3.80 min for MT and PR, respectively. The developed RP-HPLC method was validated according to Q2(R1) guideline of The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). The method was linear within the range of 2-50 µg mL-1 for PR and 10-75 µg mL-1 for MT. The developed RP-HPLC method was successfully applied on determination of MT and PR in perfusion medium. The developed method could be helpful for researchers working on in-situ rat intestinal permeability studies and it could be easily modified on further studies.

Seminal plasma does not aid in the transport of phenolsulfonphthalein across the uterotubal junction in mares.

This study tested the hypothesis that the presence of prostaglandin E2 in seminal plasma would aid in the transport of phenolsulfonphthalein (PSP) across the uterotubal junction. Five mares in estrus were inseminated during estrus with PSP dissolved in phosphate-buffered saline and during the subsequent estrus with PSP added to a standard insemination dose. Serum and urine samples were obtained at hours 0, 1, 2, and 3 following treatment and examined for the presence of PSP. Phenolsulfonphthalein could not be detected in any of the urine samples collected from mares following either treatment. None of the serum samples collected following intrauterine installation of PSP in PBS contained PSP. Phenolsulfonphthalein was detected in serum samples from 1 mare following insemination with semen containing PSP. Components in seminal plasma such as PGE2 did not facilitate the transport of PSP across the uterotubal junction as had been hypothesized.

Le plasma séminal ne facilite pas le transport de la phénolsulfonphtaléine au travers de la jonction utéro-tubaire des juments. Cette étude a testé l'hypothèse voulant que la présence de la prostaglandine E2 dans le plasma séminal facilite le transport de la phénolsulfonphtaléine (PSP) au travers de la jonction utéro-tubaire. Cinq juments en oestrus ont été inséminées avec de la PSP dissoute dans une solution saline tamponnée au phosphate et, durant l'oestrus subséquent, avec de la PSP ajoutée à une dose d'insémination standard. Des prélèvements de sérum et d'urine ont été obtenus aux heures 0, 1, 2 et 3 ainsi qu'après le traitement et examinés pour déceler la présence de la PSP. La phénolsulfonphtaléine n'a pas pu être détectée dans aucun des échantillons d'urine prélevés auprès des juments après l'un ou l'autre des traitements. Aucun des échantillons de sérum prélevés après l'installation intra-utérine de la PSP dans PBS ne contenait de PSP. La phénolsulfonphtaléine a été détectée dans des échantillons de sérum provenant d'une jument après l'insémination avec du sperme contenant de la PSP. Des composants dans le plasma séminal comme le PGE2 n'ont pas facilité le transport de la PSP au travers de la jonction utéro-tubaire conformément à l'hypothèse émise.(Traduit par Isabelle Vallières).

Bioelectronic measurement and feedback control of molecules in living cells.

We describe an electrochemical measurement technique that enables bioelectronic measurements of reporter proteins in living cells as an alternative to traditional optical fluorescence. Using electronically programmable microfluidics, the measurement is in turn used to control the concentration of an inducer input that regulates production of the protein from a genetic promoter. The resulting bioelectronic and microfluidic negative-feedback loop then serves to regulate the concentration of the protein in the cell. We show measurements wherein a user-programmable set-point precisely alters the protein concentration in the cell with feedback-loop parameters affecting the dynamics of the closed-loop response in a predictable fashion. Our work does not require expensive optical fluorescence measurement techniques that are prone to toxicity in chronic settings, sophisticated time-lapse microscopy, or bulky/expensive chemo-stat instrumentation for dynamic measurement and control of biomolecules in cells. Therefore, it may be useful in creating a: cheap, portable, chronic, dynamic, and precise all-electronic alternative for measurement and control of molecules in living cells.

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.

Multiscattering-enhanced absorption spectroscopy.

An original scheme for sensitive absorption measurements, particularly well-suited for low analyte concentrations, is presented. The technique is based on multiscattering-enhanced absorption spectroscopy (MEAS) and benefits from the advantages of conventional absorption spectroscopy: simplicity, rapidity, and low costs. The technique relies on extending the optical path through the sensing volume by suspending dielectric beads in the solution containing the analytes of interest, resulting in multiple scattering of light, which increases the optical path length through the sample. This way, a higher sensitivity and lower limit of detection, compared to those of conventional absorption spectroscopy, can be achieved. The approach is versatile and can be used for a broad variety of analytes. Here, it is applied to the detection of phenol red, 10 nm gold nanoparticles, and envy green fluorescence dye; the limit of detection is decreased by a factor of 7.2 for phenol red and a factor of 3.3 for nanoparticles and dye. The versatility of this approach is illustrated by its application in increasing the sensitivity of colorimetric detection with gold nanoparticle probes and a commercially available hydrogen peroxide bioassay. The influence of different parameters describing the scattering medium is investigated in detail experimentally and numerically, with very good agreement between the two. Those parameters can be effectively used to tailor the enhancement for specific applications and analytes.

Measurement of tear secretion in healthy pigeons by using the phenol red thread test.

The objectives of this study were to determine the applicability of the phenol red thread (PRT) test as a new method for the evaluation of tear secretion in healthy male and female pigeons, to establish normal physiologic reference values in these animals, and to compare seasonal variations in these values. Seventy-five pigeons of both sexes, with no ocular abnormalities, were included in the study. The phenol red impregnated thread was inserted into the recessus conjunctiva inferior for measuring tear secretion. After 15 seconds, the thread was removed and the wet portion of the thread was measured (in mm). The mean±sd PRT values were 23.02±2.98 mm/15 seconds and 24.04±2.60 mm/15 seconds for the April and June measurements, respectively. There were significant differences in the PRT between the two months, with a significant increase in June. Mean PRT values for males and females were, respectively, 23.30±3.35 and 22.79±2.65 mm/15 seconds in April, and 24.57±2.41 and 23.61±2.68 mm/15 seconds in June. There was no significant correlation (r=0.075, P>0.05) between bodyweight and tear production in both eyes of the male and female birds in April and June. The results indicated that seasonal variations have an effect on tear production. The PRT was a viable method for the measurement of tear production in pigeons and these measurements could be accepted as reference values for healthy pigeons.

In-situ nanospectroscopic pH monitoring by plasmon resonance energy transfer (PRET).

Real-time detection of pH value in a living cell is in central importance for research about cells and diseases. In spite of the great advances in science and technology, pH measurement in a living cell is still limited in spatial resolution, in-situ detection, and intracellular monitoring. Here, we designed a nanoscale pH meter by Plasmon Resonance Energy Transfer (PRET). In order to highly sensitively measure pH with nanoscale spatial resolution, we choose 80 nm spherical gold nanoparticle (GNP) and phenol red which is commonly used in cell media for pH determination. The resonance energy of GNP is transferred to phenol red because the scattering intensity of GNP is overlapped with the second absorption intensity of phenol red at near 560 nm. Meanwhile, the absorption intensity of phenol red molecules is changing with pH value of the solution. For that reason, the intensity of PRET from GNP to phenol red molecules also changes by the acidity of phenol red solution. Then we can detect pH values with nanoscale spatial resolution through the Rayleigh scattering intensity of GNP. As we changed pH value from 6.0 to 9.0, the scattering intensity of GNP is decreased because the absorbance of phenol red at 560 nm wavelength is increased with increasing pH value. The Gaussian peak of a difference in Rayleigh scattering spectra of GNP between pH 6.0 and pH 9.0 indicates exactly the same as UV-vis spectral difference between basic and acidic phenol red solution. We expect that this pH measuring technique has a significant impact on the pH detection of living cells with nanoscale, and it can make possibility to image the cell structure by pH variation.

A pH-based high-throughput assay for transketolase: fingerprinting of substrate tolerance and quantitative kinetics.

A pH-based high-throughput assay method has been developed for the rapid and reliable measurement of transketolase (TK) activity. The method is based on the decarboxylation of lithium hydroxypyruvate (HPA) as a hydroxyacetyl donor with an aldehyde acceptor, using phenol red as the pH indicator. Upon release of carbon dioxide from HPA, the pH increase in the reaction mixture can be determined photometrically by the color change of the pH indicator. At low buffer concentration (2 mM triethanolamine, pH 7.5), the method is highly sensitive and allows continuous monitoring, for quantitative determination of the kinetic parameters. By using this method, the substrate specificities of the TK enzymes from Escherichia coli and Saccharomyces cerevisiae, as well as two active-site-modified variants of the E. coli TK (D469E, H26Y) were evaluated against a panel of substrate analogues; specific activities and kinetic constants could be rapidly determined. Substrate quality indicated by assay determination was substantiated with novel TK applications by using achiral 3-hydroxypropanal and 4-hydroxybutanal for preparative synthesis of chiral deoxyketose-type products. Determination of ee for the latter could be performed by chiral GC analysis, with an unambiguous correlation of the absolute configuration from rotation data. This pH-based assay method is broadly applicable and allows rapid, sensitive, and reliable screening of the substrate tolerance of known TK enzymes and variants obtained from directed evolution.

Simultaneous determination of hydrazinocurcumin and phenol red in samples from rat intestinal permeability studies: HPLC method development and validation.

Hydrazinocurcumin (HZC) is a patented multiactivity compound and is a potent derivative of curcumin which is not yet explored for further development as formulation and requires the determination of biopharmaceutical suitability of the molecule. Intestinal permeability and logP of a compound are two vital biopharmaceutical properties by which, any "hit" molecule proceeds towards NCE (new chemical entity) and govern formulation design of bioactive molecules. In this report, a simple, precise and accurate isocratic reverse phase (RP) liquid chromatography method for simultaneous analysis of HZC and phenol red, for the application in rat in situ single-pass intestinal perfusion (SPIP) was developed and validated using FDA bioanalytical guidelines. RP-HPLC method was developed on C-18 column with UV detection at 332 nm for both the compounds. Isocratic run with the mobile phase consisting of organic phase (methanol:acetonitrile:: 50:20 v/v) and water in the ratio of 80:20 v/v provided a short run time of 7 min with resolution of more then two without interference of blank matrix. The working/expected concentration range for HZC and phenol red were 0.5-50 and 2-200 microg/ml. LOQs for HZC and phenol red of the method was found to be 0.167 and 0.271 microg/ml respectively. The validation parameters indicate that method was suitable for the intended purpose. Permeability, considering water flux with the help of non-permeable marker phenol red was calculated to be 0.34 x 10(-4)cm/s. Along with other descriptors, logP (1.78) and MW (<500) of HZC makes it a potential candidate for oral formulation.

High-performance liquid chromatography method development and validation for simultaneous determination of five model compounds, antipyrine, metoprolol, ketoprofen, furosemide and phenol red, as a tool for the standardization of rat in situ intestinal permeability studies using timed wavelength detection.

A simple, precise, accurate and rugged reversed-phase high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of five permeability model compounds, viz. antipyrine, metoprolol, ketoprofen, furosemide and phenol red. The method was intended to standardize rat in situ single-pass intestinal perfusion studies to assess the intestinal permeability of drugs in the market as well as new chemical entities. Optimum resolution was achieved by gradient elution on a Symmetry Shield C-18 analytical column with the mobile phase consisting of a mixture of aqueous potassium dihydrogen orthophosphate (pH 5.5; 0.01 m) and methanol at a flow rate of 1.5 mL/min. The retention times of antipyrine, metoprolol, ketoprofen, phenol red and furosemide were about 9, 12, 13, 16 and 17 min, respectively. Data acquisition was carried out using a photo diode array detector in the wavelength range 210-600 nm. Extraction of chromatograms was carried out by timed wavelength. Data obtained in all studies indicated that the method was suitable for the intended purpose. The validated method was found to be linear and precise in the working range. Suitability of storage under various conditions and freeze/thaw impact at cold temperature were established to ensure complete sample recovery without any stability issues. Recovery very close to the spiked amounts indicated that the method was highly accurate and suitable for use on routine basis.

Unbiased membrane permeability parameters for gabapentin using boundary layer approach.

The present study was performed to determine the relative contribution of both passive and nonpassive transport processes in jejunal absorption of gabapentin. The oral absorption of gabapentin was studied using in situ single pass intestinal perfusion technique in fasted rats. Unbiased intrinsic membrane absorption parameters such as maximal flux, Michaelis constant, carrier permeability, and membrane permeability were calculated using a modified boundary layer model. Gabapentin intestinal perfusion results indicate that its jejunal absorption in rats occurs via a nonpassive process, with no significant passive absorption component, as demonstrated by saturable absorption kinetics and its concentration-dependent permeability. A good correlation (r2 = 0.88) between observed human absorption fraction and calculated (from in situ rat intestine) human absorption fraction was obtained.

Validated HPLC analytical method with programmed wavelength UV detection for simultaneous determination of DRF-4367 and Phenol red in rat in situ intestinal perfusion study.

A simple, precise and accurate isocratic reverse-phase liquid chromatography method with programmed wavelength detection has been validated to quantify DRF-4367 and Phenol red, simultaneously for application in rat in situ single pass intestinal perfusion study to assess intestinal permeability of DRF-4367, a novel cox-2 inhibitor. The method was validated on RP C-18 analytical column. Mobile phase consisted of sodium dihydrogen orthophosphate (pH 3.2, 0.01 M)-acetonitrile-methanol (30:50:20, v/v/v). The developed method has a short run time of 12 min with a flow rate of 1.0 ml/min. The injector volume was set to 20 microl and acquisition was carried out using a PDA detector while processing was done by timed wavelength extraction. The percentage R.S.D. and recovery in all studies indicated that the method was suitable for the intended purpose. The validated method was found to be linear and precise in the working range. Suitability of storage at cold temperature was ensured along with complete sample recovery.

Simultaneous determination of naproxen, ketoprofen and phenol red in samples from rat intestinal permeability studies: HPLC method development and validation.

A simple reversed-phase high performance liquid chromatographic method with UV detection at 270 nm was developed for simultaneous quantitation of ketoprofen and naproxen sodium along with phenol red as a non-absorbable marker for in situ permeability studies. The mobile phase was a mixture of 20% methanol, 28% of acetonitrile, 52% water and 0.4 ml triethylamine (adjusted to pH 3.2 using orthophosphoric acid). Analysis was run at a flow of 1.5 ml/min with a 20 min run time. The calibration curves were linear for all three compounds (r>0.999) across the concentration range of 15.6-250 microg/ml with a limit of quantitation of 0.3, 0.25 and 0.2 ng/ml for naproxen, ketoprofen and phenol red, respectively. The coefficient of variation for intra-assay and inter-assay precision was less than or equal to 5.3% and the accuracy was between 95.36 and 101.6%. Using the SPIP technique and the suggested HPLC method for sample analysis, the mean values of 1.17e(-4) (+/-0.28) cm/s and 0.97e(-4) (+/-0.2) cm/s were obtained for naproxen and ketoprofen, respectively.

[Influence of single leaf Asarum himalaicum on renal function of rabbits].

OBJECTIVE: To study the influence of single leaf Asarum himalaicum on the renal function of rabbits. METHODS: Rabbits were divided into three groups. Asarum himalaicum, Asarum heterotropoides and normal saline were intravenously administered to the rabbits of one group respectively. The urine volume per minute, urine pH, urine glucose, protein and red blood cells, BUN, SCr, TXB2, 6-keto-PGF1alpha, TXB2/6-keto-PGF1alpha, endothelin, p-aminohippuric acid clearance rate and phenolsulfonphthalein excretion rate were tested before and after the administration. RESULTS: A certain dosage of single leaf Asarum himalaicum caused acute renal failure in rabbits. The indices tested were significantly different between rabbits administered Asarum himalaicum and normal saline. As compared with the rabbits administered Asarum heterotropoides, the results of indices tested decreased, but without statistical significance, except for SCr. CONCLUSION: The single leaf Asarum himalaicum can cause renal damage to rabbits. Its renal toxicity is lower that that of Asarum heterotropoides.

Continuous pH monitoring in a perfused bioreactor system using an optical pH sensor.

Monitoring and regulating the pH of the solution in a bioprocess is one of the key steps in the success of bioreactor operation. An in-line optical pH sensor, based on the optical absorption properties of phenol red present in the medium, was developed and tested in this work for use in NASA space bioreactors based on a rotating wall-perfused vessel system supporting a baby hamster kidney (BHK-21) cell culture. The sensor was tested over three 30-day and one 124-day cell runs. The pH sensor initially was calibrated and then used during the entire cell culture interval. The pH reported by the sensor was compared to that measured by a fiber optically coupled Shimadzu spectrophotometer and a blood gas analyzer. The maximum standard error of prediction for all the four cell runs for development pH sensor against BGA was +/-0.06 pH unit and for the fiber optically coupled Shimadzu spectrophotometer against the blood gas analyzer was +/-0.05 pH unit. The pH sensor system performed well without need of recalibration for 124 days.