Serological investigation of brucella infection using a dipstick assay among individuals with unexplained fever in farming-pastoral areas of Xinjiang, China.

OBJECTIVE: To evaluate the brucellosis detection of the dipstick assay coated with LPS antigen from Brucella melitensis vaccine strain M5 compared with Rose Bengal test (RB) and serum agglutination test (SAT), and investigate the brucella infection with the dipstick assay among people with unexplained fever in farming-pastoral areas of Xinjiang, China. METHODS: The dipstick assay was repeated to verify 130 positive and 200 negative serum samples, which had been confirmed by RB and SAT, for sensitivity and specificity analysis. Subsequently, 313 sera from people with unexplained fever in farming-pastoral areas including 6 counties in 3 regions where brucellosis is endemic and 200 sera from nonendemic city area (Urumqi City) in Xinjiang were detected with the dipstick assay for population infection rate survey. RESULTS: Sensitivity and specificity was 100% and 97% respectively with dipstick assay compared with RB and SAT. The average positive rate of sera from people with unexplained fever from farming-pastoral areas in Xinjiang was 18.5% (58/313) and the highest was 22.5% (9/40). CONCLUSIONS: The proportion of brucellosis infection among individuals with fever of unknown origin is relatively high in agricultural and pastoral areas of Xinjiang. The dipstick assay has a series of advantages such as low cost and fast speed, which make it suitable for the primary screening of high-risk populations.

Influence of Rose Bengal Dimerization on Photosensitization.

Protein crosslinking photosensitized by rose Bengal (RB2- ) has multiple medical applications and understanding the photosensitization mechanism can improve treatment effectiveness. To this end, we investigated the photochemical efficiencies of monomeric RB2- (RBM 2- ) and dimeric RB2- (RBD 2- ) and the optimal pH for anaerobic RB2- photosensitization in cornea. Absorption spectra and dynamic light scattering (DLS) measurements were used to estimate the fractions of RBM 2- and RBD 2- . RB2- self-photosensitized bleaching was used to evaluate the photoactivity of RBM 2- and RBD 2- . The pH dependence of anaerobic RB2- photosensitization was evaluated in ex vivo rabbit corneas. The 549 nm/515 nm absorption ratio indicated that concentrations > 0.10 mm RB contained RBD 2- . Results from DLS gave estimated mean diameters for RBM 2- and RBD 2- of 0.70 ± 0.02 nm and 1.75 ± 0.13 nm, respectively, and indicated that 1 mm RB2- contained equal fractions of RBM 2- and RBD 2- . Quantum yields for RB2- bleaching were not influenced by RBD 2- in RB2- solutions although accounting for RB2- concentration effects on the reaction kinetics demonstrated that RBD 2- is not a photosensitizer. Optimal anaerobic photosensitization occurred at pH 8.5 for solutions containing 200 mm Arg. These results suggest potential approaches to optimizing RBM 2- -photosensitized protein crosslinking in tissues.

A retrospective study (2007-2015) on brucellosis seropositivity in livestock in South Africa.

In South Africa, brucellosis testing and record-keeping are done by several laboratories, thus it is difficult to access any organized data to assess the status of the disease. This study evaluated the seropositivity for brucellosis using Rose Bengal test and complement fixation test in suspect cattle, sheep, goats and pigs sera submitted to Bacterial Serology Laboratory, Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR) from nine provinces in the country during the period 2007-2015. This retrospective data analysis was conducted to estimate the occurrence of brucellosis in the country from the submitted samples, identify variables that affected seropositivity for brucellosis, investigate existing gaps in data recording and make recommendations on important variables to facilitate better data capture and inferences on brucellosis. Nine years of data were collated and analysed to detect association (seropositivity over time regarding animal species and location). Of the 764,276 animals tested, the distribution of samples was 90.50% (691,539/764,276), 5.19% (39,672/764,276), 3.92% (29,967/764,276) and 0.41% (3,098/764,276) for cattle, sheep, goats and pigs, respectively. The seropositivity for brucellosis by animal species was 6.31% (43,666/691,539, 95% CI: 6.26-6.37), 2.09% (828/39,672, 95% CI: 1.95-2.23), 0.63% (189/29,967, 95% CI: 0.55-0.73) and 0.13% (4/3,098, 95% CI: 0.05-0.33) in cattle, sheep, goats and pigs respectively. The data available did not capture information on the age, sex, breed and other host risk factors that would have been related to seropositivity for brucellosis. The data provide an understanding of the disease occurrence and confirm that brucellosis is enzootic in South Africa. Improved and standardized data collection can be used to pro-actively drive, monitor, change or formulate policies to mitigate the challenges brought about by brucellosis in the livestock sector in South Africa.

Application of Pineapple Leaves as Adsorbents for Removal of Rose Bengal from Wastewater: Process Optimization Operating Face-Centered Central Composite Design (FCCCD).

Adsorptive removal of rose bengal (RB) from contaminated water samples was approached using pineapple leaves (PAL). Three adsorbents were utilized for that purpose; raw pineapple leaves (RPAL) and the thermally activated bio-waste leaves at 250 and 500 °C. Two measures were executed to evaluate the functionality of exploited biomasses; percentage removal (%R) and adsorption capacity (qe). Face-centered central composite design (FCCCD) was conducted to experiment the influence of variables on the %R. Dose of PAL as adsorbent (AD), concentration of RB (DC), pH and contact time (CT), were the inspected factors. Existence of functional groups and formation of activated carbon was instigated employing Fourier-transform infrared (FT-IR) and Raman spectroscopies. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses were used to explore surface features. Thermal behavior of adsorbents was studied using thermogravimetric analysis (TGA). The surface area and other surface structural properties were established using the Brunauer Emmett-Teller (BET) analysis. An amount of 92.53% of RB could be removed with an adsorption capacity of 58.8 mg/g using a combination of pH 5.00 ± 0.20, RPAL dose of 0.05 mg/50 mL, and 10-ppm RB for 180 min. Equilibrium studies divulge a favorable adsorption that follows the Freundlich isotherm. Pseudo-second-order model explains the observed adsorption kinetics.

Silica nanoparticles doped with anthraquinone for lung cancer phototherapy.

In the present study, SiO2 nanoparticles functionalized with 3-(2-aminoethylamino)propyl group (SiNP-AAP) were used, for the first time, to covalently bond rose bengal (SiNP-AAP-RB) or 9,10-anthraquinone-2-carboxylic acid (SiNP-AAP-OCAq). The functionalized SiNP were characterized by: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM); elemental analysis (CHN) for determination of the dye concentration; FTIR and UV-vis diffuse reflectance (DR-UV-vis) and a surface area study (BET). The functionalized SiNPs were applied in photodynamic therapy (PDT) against lung cancer cell lines. The evaluated cytotoxicity revealed 20-30% cell survival after 15min of PDT for both materials but the OCAq concentration was half of the RB nanomaterial. The phototoxicity was mainly related to oxidative stress generated in the cellular environment by singlet oxygen and by hydrogen abstraction as confirmed by the laser flash photolysis technique. The unprecedented results indicate that SiNP-AAP-OCAq is a possible system for promoting cell apoptosis by both type I and type II mechanisms.

Investigation of two-photon excited fluorescence increment via crosslinked bovine serum albumin.

The two-photon excited fluorescence (TPEF) increments of two dyes via bovine serum albumin (BSA) microstructures fabricated by the two-photon crosslinking technique were investigated. One is Rose Bengal (RB) with a high non-radiative decay rate, while the other is Eosin Y with a low non-radiative decay rate. Experimental results demonstrate that the quantum yield and lifetime of RB are both augmented via crosslinked BSA microstructures. Compared with theoretical analysis, this result indicates that the non-radiative decay rate of RB is decreased; hence, the quenched effect induced by BSA solution is suppressed. However, the fluorescence lifetime of Eosin Y is acutely abated despite the augmented quantum yield for the two-photon crosslinking processing from BSA solution. This result deduces that the radiative decay rate increased. Furthermore, the increased TPEF intensity and lifetime of RB correlated with the concentration of fabricated crosslinked BSA microstructures through pulse selection of the employed femtosecond laser is demonstrated and capable of developing a zone-plate-like BSA microstructure.

Changes of the ocular surface and aquaporins in the lacrimal glands of rabbits during pregnancy.

PURPOSE: To test the hypotheses that pregnancy represents a physiologic condition that is associated with dry eye symptoms, and the expression of aquaporin 4 (AQP4) and AQP5 are altered in the lacrimal gland (LG) from term pregnant rabbits. METHODS: Schirmer's test, tear break-up time (BUT), and Rose Bengal staining were used to evaluate ocular surface health. LG were obtained from term pregnant rabbits and age-matched female control rabbits and then processed for laser capture microdissection (LCM), real time RT-PCR, western blot, and immunofluorescence for the detection and quantification of mRNA and proteins of AQP4 and AQP5. RESULTS: Pregnant rabbits demonstrated typical clinical symptoms of dry eye, including decreased Schirmer score and BUT as well as increased Rose Bengal staining of cornea. In term pregnant rabbits, mRNA for AQP5 from whole LG was significantly lower than that of control rabbits, while mRNA for AQP4 was not. Levels of mRNA for AQP4 and AQP5 underwent significant changes in acini and epithelial cells from specific duct segments during pregnancy. Western blot from whole LG lysates demonstrated that expression of AQP4 was 24% more abundant in term pregnant rabbits while AQP5 was 22% less when compared to control rabbits respectively. At term pregnancy, AQP4 immunoreactivity (AQP4-IR) was increased in acini while its intensity remained the same in ducts. AQP5-IR was present in both apical and basolateral membranes of acinar cells in normal control and pregnant rabbits, while ductal cells in pregnant rabbits also showed significant amount of AQP5-IR. CONCLUSIONS: The data presented here demonstrated significant dry eye symptoms in pregnant rabbits. Our data also showed altered expressions of AQP4 and AQP5 during pregnancy and suggested that these changes may contribute to the altered LG secretion and dry eye symptoms during pregnancy.

Multivariate standard addition method solved by net analyte signal calculation and rank annihilation factor analysis.

This article describes the use of the net analyte signal (NAS) concept and rank annihilation factor analysis (RAFA) for building two different multivariate standard addition models called "SANAS" and "SARAF." In the former, by the definition of a new subspace, the NAS vector of the analyte of interest in an unknown sample as well as the NAS vectors of samples spiked with various amounts of the standard solutions are calculated and then their Euclidean norms are plotted against the concentration of added standard. In this way, a simple linear standard addition graph similar to that in univariate calibration is obtained, from which the concentration of the analyte in the unknown sample and the analytical figures of merit are readily calculated. In the SARAF method, the concentration of the analyte in the unknown sample is varied iteratively until the contribution of the analyte in the response data matrix is completely annihilated. The proposed methods were evaluated by analyzing simulated absorbance data as well as by the analysis of two indicators in synthetic matrices as experimental data. The resultant predicted concentrations of unknown samples showed that the SANAS and SARAF methods both produced accurate results with relative errors of prediction lower than 5% in most cases.

[Analysis of hexachlorobenzene in Food Red Nos. 104 (phloxine) and 105 (rose Bengal) by GC-ECD].

A simple and rapid method using electron capture detector gas chromatography (GC-ECD) was developed for the determination of hexachlorobenzene (HCB) in Food Red Nos. 104 and 105. The sample was dissolved in water and HCB was extracted with hexane. The GC-ECD operating conditions were as follows: column, InertCap 5 MS/NP (30 m x 0.25 mm i. d. with 0.25 microm film thickness); oven temperature, 60 degrees C(1 min)-->20 degrees C/min-->150 degrees C(10 min)-->20 degrees C/min-->280 degrees C(5 min); inlet temperature, 260 degrees C; detector temperature, 300 degrees C; carrier gas, nitrogen (constant press 25 psi); inlet mode, splitless. For the evaluation of the method, HCB spiked into R104 and R105 at the levels of 2 microg/g and 5 microg/g was determined in replicate in five laboratories. Mean recoveries of HCB from R104 and R105 were 98.2-103.7%. Repeatability relative standard deviation values were 2.9-6.0% and reproducibility relative standard deviation values were 4.2-9.3%. HORRAT value was less than one. From these results, the validity of this method was confirmed.

Apoptosis in tumour cells photosensitized with Rose Bengal acetate is induced by multiple organelle photodamage.

Rose Bengal (RB) is a very efficient photosensitizer which undergoes inactivation of its photophysical and photochemical properties upon addition of a quencher group-i.e. acetate-to the xanthene rings. The resulting RB acetate (RB-Ac) derivative behaves as a fluorogenic substrate: it easily enters the cells where the native photoactive molecule is restored by esterase activities. It is known that the viability of RB-Ac-loaded cells is strongly reduced by light irradiation, attesting to the formation of intracellular RB. The aim of this study was to identify the organelles photodamaged by the intracellularly formed RB. RB-Ac preloaded rat C6 glioma cells and human HeLa cells were irradiated at 530 nm. Fluorescence confocal imaging and colocalization with specific dyes showed that the restored RB molecules redistribute dynamically through the cytoplasm, with the achievement of a dynamic equilibrium at 30 min after the administration, in the cell systems used; this accounted for a generalized damage to several organelles and cell structures (i.e. the endoplasmic reticulum, the Golgi apparatus, the mitochondria, and the cytoskeleton). The multiple organelle damage, furthermore, led preferentially to apoptosis as demonstrated by light and electron microscopy and by dual-fluorescence staining with FITC-labelled annexin V and propidium iodide.

[Structural analysis of unknown dyes detected in hajikami (ginger pickled in vinegar)].

Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.

AtHsfA2 modulates expression of stress responsive genes and enhances tolerance to heat and oxidative stress in Arabidopsis.

There is increasing evidence for considerable interlinking between the responses to heat stress and oxidative stress, and recent researches suggest heat shock transcription factors (Hsfs) play an important role in linking heat shock with oxidative stress signals. In this paper, we present evidence that AtHsfA2 modulated expression of stress responsive genes and enhanced tolerance to heat and oxidative stress in Arabidopsis. Using Northern blot and quantitative RT-PCR analysis, we demonstrated that the expression of AtHsfA2 was induced by not only HS but also oxidative stress. By functional analysis of AtHsfA2 knockout mutants and AtHsfA2 overexpressing transgenic plants, we also demonstrated that the mutants displayed reduced the basal and acquired thermotolerance as well as oxidative stress tolerance but the overexpression lines displayed increased tolerance to these stress. The phenotypes correlated with the expression of some Hsps and APX1, ion leakage, H202 level and degree of oxidative injuries. These results showed that, by modulated expression of stress responsive genes, AtHsfA2 enhanced tolerance to heat and oxidative stress in Arabidopsis. So we suggest that AtHsfA2 plays an important role in linking heat shock with oxidative stress signals.

Specificity dependence between serological tests for diagnosing bovine brucellosis in Brucella-free farms showing false positive serological reactions due to Yersinia enterocolitica O:9.

When brucellosis false positive serological reactions happen in cattle, the serial use of pairs of specificity-correlated serological tests (rose bengal, complement fixation, competitive ELISA) results in specificities lower than expected. In this situation, highly specific tests, such as the indirect ELISA used alone, may be more adequate than serial testing.

Avaliação de diferentes técnicas para coloração de sêmen de peixes / Different techniques to evaluate to stain fish semen / Evaluación de técnicas para colorear sémen de peces

A análise da morfologia dos espermatozóides do sêmen colhido de 30 pacus (Piaractus mesopotamicus) consistiu de três soluções fixadoras: formol salina tamponada (FS), citrato sódio diidratado a 3% (CS) e água destilado (Ag) e para corar as células espermáticas três corantes: Vermelho Congo (VC), Rosa Bengala (RB) e Williams-modificado (WM). As combinações de corantes e soluções fixadoras utilizadas foram: RB X FS, WM X FS, VC X FS, VC X Ag, WM X Ag, WM X CS e VC X CS. Na avaliação dos esfregaços levaram-se em consideração as alterações anatômicas, a eficiência do corante, a aglutinação e a sujidade. Quando o sêmen foi diluído em CS e Ag, os espermatozóides sofreram alterações anatômicas e aglutinação, inviabilizando a análise. O FS não gerou alteração anatômica e nem aglutinação dos espermatozóides, sendo possível avaliar a eficiência do corante. Ao analisar a combinação RB X FS verificou-se a melhor média estimada de 9,97 pontos (P<0,05), com baixa sujidade e boa eficiência do corante. A combinação WM X FS resultou na média estimada de 7,35 pontos e a do VC X FS de 6,83 pontos que foram valores menores (P<0,05) em comparação aos esfregaços da combinação RB X FS. De acordo com os resultados obtidos neste estudo, a combinação do RB X FS apresentou os melhores resultados, sendo recomendado preparar esfregaços para analisar a morfologia dos espermatozóides de pacus (Piaractus mesopotamicus).

The analyses of spermatozoa morphology from semen obtained from pacus (Piaractus mesopotamicus) consisted of three fi xers solution: formal-saline buffered (FB), 3 % sodium citrate diihydrated (SC) and distilled water (DW) and to stain the spermatic cells were used three dyeing: Congo red (CR), Bengal rose (BR) and Williams modifi ed (WM). Combinations of dyeing and fi xers solution were: BR x BF, WM x FB, CR x FB, CR x DW, WM x DW, WM x SC and CR x SC. In the rubbing brush stained evaluation was considered spermatozoa anatomic alterations, dyeing effi ciency, agglutination and dirtiness. For semen diluted in SC and DW was observed spermatozoa anatomic alterations and agglutination on the rubbing brush, becoming impossible any analyses. When semen was diluted in FB to prepare rubbing brush was not observed spermatozoa anatomic alterations and agglutination, becoming possible to evaluate dyeing effi ciency. In analyze of BR x FB combination was verifi ed the best estimate average of 9.97 points (P<0.05), showing reduced dirtiness and good effi ciency of dyeing. When combination was WM x FB the estimate average was 7.35 points and CR x FB was 6.83 points which were lower (P<0.05) than the average verifi ed in the rubbing brush stained with BR x FB. According to the results observed in this study, the best combination to evaluate spermatozoa morphology from pacus semen was rubbing brush stained with BR x FB combination.

El análisis de la morfologia de los espermatozoides del semen colectado de 30 pacus (Piaractus mesopotamicus) consistio en tres soluciones fi jadoras: Formol salina tamponada (FS), citrato sodio bihidratado al 3% (CS) y agua destilada (Ag) y para colorear las células espermáticas tres colorantes: Rojo Congo (VC), Rosa Bengala (RB) y Williams ­ modifi cado (WM). Las combinaciones de colorantes y soluciones fi jadoras utilizadas fueron: RB x FS, WB x FS, VC x FS, VC x Ag, WM x Ag, WM x CS y VC x CS. En la evaluación de los frotis se tuvo en cuenta las alteraciones anatómicas, la efi ciencia del colorante, la aglutinacion y la suciedad. Cuando el semen fue diluído en CS y Ag, los espermatozoides sufrieron alteraciones anatómicas y aglutinación, inviabilizando el análisis. El FS no generó alteracion anatómica ni aglutinación de losespermatozoides, siendo posible evaluar la efi ciencia del colorante. Al analizar la combinación RB x FS se verifi có la mejor média estimada de 9,97 puntos (P〈0,05) con baja suciedad y buena efi ciencia del colorante. La combinación WM x FS resultó en el promedio estimado de 7,35 puntos y la de VC x FS de 6,83 puntos que fueron valores menores (P〈0,05) en comparación a los frotis de la combinación RB x FS. De acuerdo con los resultados obtenidos en este estudio, la combinación de RB x FS presentó los mejores resultados, siendo recomendado para preparar frotis para analizar la morfologia de los espermatozoides de pacus (Piaractus mesopotamicus).

Cell cycle regulation of the murine 8-oxoguanine DNA glycosylase (mOGG1): mOGG1 associates with microtubules during interphase and mitosis.

8-Oxoguanine DNA glycosylase (OGG1) is a major DNA repair enzyme in mammalian cells. OGG1 participates in the repair of 8-oxoG, the most abundant known DNA lesion induced by endogenous reactive oxygen species in aerobic organisms. In this study, antibodies directed against purified recombinant human OGG1 (hOGG1) or murine (mOGG1) protein were chemically conjugated to either the photosensitizer Rose Bengal or the fluorescent dye Texas red. These dye-protein conjugates, in combination with binding assays, were used to identify associations between mOGG1 and the cytoskeleton of NIH3T3 fibroblasts. Results from these binding studies showed that mOGG1 associates with the cytoskeleton by specifically binding to the centriole and microtubules radiating from the centrosome at interphase and the spindle assembly at mitosis. Similar results were obtained with hOGG1. Together results reported in this study suggest that OGG1 is a microtubule-associated protein itself or that OGG1 utilizes yet to be identified motor proteins to ride on microtubules as tracks facilitating the movement and redistribution of cytoplasmic OGG1 pools during interphase and mitosis and in response to oxidative DNA damage.

[The early changes of tear film after laser in situ keratomileusis].

OBJECTIVE: To investigate the early changes of tear film after laser in situ keratomileusis (LASIK). METHODS: One hundred and forty-eight myopic eyes that underwent LASIK were randomly chosen. The eyes were observed for subjective complaints of dry eye, fluorescein staining (Fl), rose bengal staining (Rb), tear break-up time (BUT), Schirmer's I test preoperatively and 1 day, 1 week, 1 month, 3 months postoperatively. RESULTS: The subjective complaints of dry eye were more severe after the operation. There were obvious decreases in BUT at 1 day, 1 week, 1 month and 3 months postoperatively relative to the preoperative level (P < 0.05). The Schirmer's I test result was higher at 1 day but without statistical significance (P > 0.05), but lower at 1 week, 3 months (P < 0.05) after LASIK. No changes were observed in Schirmer's I test between preoperative and 1 month postoperative value (P > 0.05). Rb and Fl staining dots were more concentrated at 1 day and 1 week postoperatively (P < 0.0127). No significant changes were found in Rb staining at 1 month and 3 months postoperatively. CONCLUSION: LASIK does have some effects on tear film.

Seroprevalencia de brucella en donantes de sangre / Seroprevalence of brucella in donors of blood

Propósito: Conocer el impacto de la brucellosis en los Bancos de Sangre. Materiales y Métodos: Se realizó la prueba de Rosa de Bengala a 194 donantes de sangre de Lima y Callao. Resultados: Cinco personas presentaron serología positiva Brucella (2,58 por ciento) de los cuales uno corresponde al Callao (3,6 por ciento), tres a Barranca (2,9 por ciento), uno a Supe (3,0 por ciento) y ninguno a Paramonga. De los 100 donantes voluntarios, ninguno fue positivo a Brucella, en tanto que de los 94 donantes por reposición cinco (5,3 por ciento) fueron positivos. Discusión: Se evidencia que entre los donantes de sangre existen portadores de brucellosis que, eventualmente, podrían transmitir esta enfermedad a los que reciben esta sangre contaminada. En los donantes voluntarios, no se encuentra caso alguno. Esto amerita más estudios a fin de verificar lo anteriormente obtenido, así como investigar si se presentaron casos de Brucellosis post-transfusional.

Non specific serological reactions in the diagnosis of bovine brucellosis: experimental oral infection of cattle with repeated doses of Yersinia enterocolitica O:9.

Eight heifers were orally infected with 4 x 10(9) colony forming units of a field cattle strain of Yersinia enterocolitica O:9 in a capsule, 5 days a week, for about 9 weeks (day 0-day 64 (D0-D64). The faecal shedding of Y. enterocolitica O:9 began on D5 for seven out of the eight challenged cattle with a high level of excretion during the first month, followed by a decrease till the day of slaughter (D76). Y. enterocolitica O:9 was not isolated from organs collected at slaughter. No clinical symptoms were observed. Hyperplasia of intestinal lymph formations was the sole microscopic lesions observed. Five animals showed a serological reaction against Brucella antigens in at least one of the following tests: Rose-Bengal test, complement fixation test, tube agglutination test or indirect ELISA (iELISA) tests. Only one animal showed a high level of serological response and a positive reaction in the dithiothreitol-microagglutination test. The observed variability in terms of individual sensitivity to the Y. enterocolitica O:9 infection is in agreement with the low individual prevalence rate and the transient serological reaction and faecal Y. entercolitica O:9 shedding observed in herds showing false positive serological reactions in brucellosis.

Improved functional recovery of ischemic rat hearts due to singlet oxygen scavengers histidine and carnosine.

There is increasing evidence that reactive oxygen species (ROS) contribute to post-ischemic reperfusion injury, but determination of the specific ROS involved has proven elusive. In the present study electron paramagnetic resonance (EPR) spectroscopy was used in vitro to measure the relative quenching of singlet oxygen (1O2) by histidine and carnosine (beta-alanyl-L-histidine) utilizing the hindered secondary amine 2,2,6,6-tetramethyl-4-piperidone HCl (4-oxo-TEMP). The relative effect of histidine and carnosine on functional recovery of isolated perfused rat hearts was also studied. Functional recovery was measured by left ventricular developed pressure (LVDP), first derivative of left ventricular pressure (dP/dt), heart rate (HR) and coronary flow (CF). EPR measurements and Stern-Volmer plots showed that 400 microM carnosine quenched 1O2 twice as effectively as equimolar histidine in vitro. Moreover, 10 mM histidine improved functional recovery of isolated rat hearts significantly more than 1 mM histidine. Furthermore, 1 mM carnosine improved functional recovery significantly more than equimolar histidine and as effectively as 10 mM histidine. Experiments with 1 mM mannitol, a known hydroxyl radical scavenger, did not show an improvement in functional recovery relative to control hearts, thereby decreasing the likelihood that hydroxyl radicals are the major damaging species. On the other hand, the correlation between improved functional recovery of isolated rat hearts with histidine and carnosine and their relative 1O2 quenching effectiveness in vitro provides indirect evidence for 1O2 as ROS participating in reperfusion injury.

Does paracellular permeability play a role in cholephilic dye-induced cholestasis?

Changes in hepatic paracellular permeability were investigated during the development of cholephilic dye-induced cholestasis in rats. For this purpose, four dyes with different cholestatic potency (phenol red, sulfobromophthalein, bromcresol green and rose bengal) were infused at a high, potentially damaging dose (280 nmol/min per 100 g body wt., i.v.), and changes in paracellular permeability were continuously monitored by measuring the access into bile of the permeability probe -14C-sucrose. The cholestatic potency of the different dyes was: rose bengal > bromcresol green > sulfobromophthalein > phenol red. All dyes increased [14C]sucrose bile-to-plasma ratio, producing a displacement towards curves of higher permeability. The capability of the dyes to increase biliary permeability followed the same order as their respective cholestatic potencies. The possible implications of the present results for cholephilic dye-induced cholestasis are discussed.