Genetic diversity of Mycobacterium avium complex strains isolated in Argentina by MIRU-VNTR.

Mycobacterium avium sp. avium (MAA), M. avium sp. hominissuis (MAH), and M. avium sp. paratuberculosis (MAP) are the main members of the M. avium complex (MAC) causing diseases in several hosts. The aim of this study was to describe the genetic diversity of MAC isolated from different hosts. Twenty-six MAH and 61 MAP isolates were recovered from humans and cattle, respectively. GenoType CM® and IS1311-PCR were used to identify Mycobacterium species. The IS901-PCR was used to differentiate between MAH and MAA, while IS900-PCR was used to identify MAP. Genotyping was performed using a mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) scheme (loci: 292, X3, 25, 47, 3, 7, 10, 32) and patterns (INMV) were assigned according to the MAC-INMV database (http://mac-inmv.tours.inra.fr/). Twenty-two (22/26, 84·6%) MAH isolates were genotyped and 16 were grouped into the following, INMV 92, INMV 121, INMV 97, INMV 103, INMV 50, and INMV 40. The loci X3 and 25 showed the largest diversity (D: 0·5844), and the global discriminatory index (Hunter and Gaston discriminatory index, HGDI) was 0·9300. MAP (100%) isolates were grouped into INMV 1, INMV 2, INMV 11, INMV 8, and INMV 5. The HGDI was 0·6984 and loci 292 and 7 had the largest D (0·6980 and 0·5050). MAH presented a higher D when compared with MAP. The MIRU-VNTR was a useful tool to describe the genetic diversity of both MAH and MAP as well as to identify six new MAH patterns that were conveniently reported to the MAC-INMV database. It was also demonstrated that, in the geographical region studied, human MAC cases were produced by MAH as there was no MAA found among the human clinical samples.

Perfluorooctane sulfonate effects on the reproductive axis in adult male rats.

Perfluorooctane sulfonate (PFOS) is a neurotoxic agent and it can disrupt the endocrine system activity. This work was undertaken to evaluate the possible effects of PFOS exposure on the hypothalamic-pituitary-testicular axis (HPT) in adult male rats, and to evaluate the possible morphological alterations induced by PFOS in the endocrine tissues of this axis. Adult male rats were orally treated with 0.5; 1.0; 3.0 and 6.0 mg of PFOS/kg/day for 28 days. After PFOS exposure, hypothalamic noradrenaline concentration increased in the anterior hypothalamus and in the median eminence, not changing in the mediobasal hypothalamus. PFOS treated rats presented a decrease of the gonadotropin releasing hormone (GnRH) gene expression, increasing the mRNA levels of the luteinizing hormone (LH) in rats treated with all doses administered except with the dose of 6 mg/kg/day. PFOS also induced a raise of the follicle stimulating hormone (FSH) gene expression in the animals exposed to 0.5 and 1.0 mg of PFOS/kg/day. After PFOS exposure, hypothalamic GnRH concentration was modified, LH and testosterone release was inhibited and FSH secretion was stimulated. Moreover, PFOS induced several histopathological alterations in the hypothalamus, pituitary gland and testis. The results obtained in the present study suggest in general terms that PFOS can inhibit the physiological activity of the reproductive axis in adult male rats, which could be explained, at least in part, by the structural alterations showed in the animals exposed to this chemical: very dense chromatin, condensed ribosomes and a loss of the morphology in the hypothalamus; a degeneration of the gonadotrophic cells, as well as a loss and degeneration of the spermatozoids and a very marked edema in the testis.

Post-immunobiotics increase resistance to primary respiratory syncytial virus infection and secondary pneumococcal pneumonia.

Previously, we demonstrated that post-immunobiotics derived from Lactobacillus gasseri TMT36, TMT39, and TMT40 strains (HK36, HK39 and HK40, respectively) differentially regulated Toll-like receptor 3 (TLR3)-mediated antiviral respiratory immunity in infant mice. In this work, we investigated whether the HK36, HK39 and HK40 nasal treatments were able to improve the resistance against primary respiratory syncytial virus (RSV) infection and secondary pneumococcal pneumonia. Our results demonstrated that the three treatments increased the resistance to primary viral infection by reducing variations in body weight, RSV titers and lung damage of infected infant mice. Post-immunobiotics significantly enhanced the expressions of interferon (IFN)-λ, IFN-ß, IFN-γ, interleukin(IL) - 1ß, IL-6, IL-27, Mx1, RNAseL and 2'-5'-oligoadenylate synthetase 1 (OAS1) genes and decreased tumour necrosis factor (TNF)-α in alveolar macrophages of RSV-challenged mice. In addition, the studies in the model of RSV-Streptococcus pneumoniae superinfection showed that the HK39 and HK40 treatments were capable of reducing lung damage, lung bacterial cell counts, and the dissemination of S. pneumoniae into the blood of infant mice. The protective effect was associated with increases in IFN-ß, IFN-γ, IL-10, and IL-27 in the respiratory tract. This study demonstrates that the nasal application of the post-immunobiotics HK39 and HK40 stimulates innate respiratory immunity and enhances the defences against primary RSV infection and secondary pneumococcal pneumonia offering an alternative to combat respiratory superinfections in children, which can be fatal.

Practical diagnosis of red cell disorders in southern Spain.

BACKGROUND: Hereditary red cell disorders are associated with a protective effect against malaria, which results in an increased prevalence in malaria-endemic areas. Migratory flows from these areas are resulting in a marked increase in such abnormalities in Southern Spain. METHODS: All hemoglobin disorders diagnosed between 1997 and 2010 have been recorded. Since 2008, we have performed systematic screening for hemoglobinopathies on African patients. A high-pressure liquid chromatography system was used as screening method for structural hemoglobinopathies and for separation of hemoglobin (Hb) F and A(2). RESULTS: We detected 666 cases in patients of foreign origin and 308 in native Spanish patients. Thalassemias (thal) are the most frequent disorders amongst the local population: ß-thal minor, 57.1% (176/308); α-thal, 18.2% (56/308), and δß-thal, 7.8% (24/308). In ethnic minorities, there is a huge variety of hemoglobinopathies: heterozygous Hb S, 45% (300/666); heterozygous Hb C, 15% (100/666); ß-thal minor, 13.7% (91/666); α-thal, 10.2% (68/666); Hb SS in 14 patients, and Hb CC in 9 patients. Of the native patients, 14 were found to have Hb AS and 9 Hb AC. CONCLUSION: Given the modern migratory flows, greater knowledge of these disorders is needed by all medical staff, and new practical and cost/time-effective diagnostic approaches have to be devised.

Incidence, prognosis, and prediction of haemorrhagic transformation after revascularisation for stroke.

INTRODUCTION: Haemorrhagic transformation is a major complication of acute ischaemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial haemorrhage (ICH) after revascularisation therapy. METHODS: We conducted a retrospective, single-centre study including 235 patients with AIS who underwent intravenous recombinant tissue plasminogen activator (IV-rtPA) therapy and/or endovascular treatment. A binary logistic regression model was used to determine the variables associated with ICH, parenchymal haematomas (PH), modified Rankin Scale (mRS) scores, and mortality. RESULTS: ICH was detected in 57 (30 with PH) of 183 patients included. Mechanical thrombectomy, either alone (OR 3.3 [1.42-7.63], P=.005) or in combination with IV-rtPA (OR 3.39 [1.52-7.56], P=.003), was associated with higher risk of ICH, while higher Alberta Stroke Program Early CT scores (OR 0.71 [0.55-0.91], P=.007) were associated with lower risk. Patients with older age (OR 1.07 [1.02-1.13], P=.006) and occlusion of the terminal branch of the internal carotid artery (OR 4.03 [1.35-11.99], P=.012) had a higher risk of PH, while the use of IV-rtPA alone (OR 0.24 [0.08-0.68], P=.008) was associated with lower risk of PH. Only PH was associated with disability as measured by the mRS (OR 3.2 [1.17-8.76], P=.02) and higher mortality (OR 5.06 [1.65-15.5], P=.005). CONCLUSIONS: Greater understanding about the predictors of ICH, mRS scores, and mortality could enable better selection of patients and treatments.

New and rapid strategies for the diagnosis of bovine paratuberculosis "in situ" using latex particles.

The chemical coupling of a protoplasmatic antigen from Mycobacterium avium subsp. paratubeculosis onto core-shell carboxylated particles was investigated with the aim of producing latex-protein complexes to be used in immunoagglutination assays capable of detecting bovine paratuberculosis disease. For this purpose, sensitizations were carried out using both colored and not colored carboxylated latexes as well as the protoplasmatic antigen at pH close to its isoelectric point to favor the antigenic protein to approach the particle surface. In all cases, higher fractions of proteins were chemically-bound to carboxyl groups on the surface of the particles. The assessment of the performance of the visual immunoagglutination assays consisted of evaluating 111 sera from healthy and infected bovines with Mycobacterium avium subsp. paratuberculosis. Complexes obtained from the colored latex allowed an acceptable visual discrimination between the studied positive and negative sera. Most of the positive samples showed strong to very strong agglutination and only a few samples reacted weakly, i.e. a sensitivity of 70%. The specificity of the assay, on the other hand, was 86%. Therefore, this rapid detection technique allows an easy and inexpensive identification of animals possibly infected with paratuberculosis "in situ" in the herds.

Development and diagnostic validation of an ELISA based on an antigenic mixture for the detection of bovine tuberculosis.

Programs for the eradication of bovine tuberculosis (bTB) focus on the tuberculin skin test (TST) and slaughter of reactor cattle. However, the disease remains an animal health concern in several countries and improving the efficiency of the TST has become a critical issue. The detection of Mycobacterium bovis antibodies in serum, within weeks after the TST, may be a rapid and inexpensive way to improve bTB control. This study reports the validation of an enzyme-linked immunosorbent assay (ELISA) to detect bovine tuberculosis as an ancillary test to TST in dairy farms in Argentina. The estimated validation parameters were within the established requirements of the World Organization for Animal Health (OIE). The test demonstrated high repeatability, with coefficients of variation <25%. High test reproducibility through interlaboratory testing was also found, with an estimated Pearson coefficient of 0.9648 (95% confidence intervals 0.9315-0.9820). The ELISA detected tuberculous cattle unidentified by the TST. Of 43 animals sent to slaughterhouses that were ELISA positive 15-17 days after a negative TST, 36 were confirmed as infected with M. bovis by histopathology and IS6110 PCR. According to ROC curve analysis of results of 145 cattle from M. bovis-free herds and the 36 M. bovis-infected cattle, at a corrected optical density cut-off point of 0.3853, specificity was 95.95% and the positive predictive value at this cut-off was 83.72%. The ELISA detection test validated in this study could be readily applied in dairy farms, to complement a prior TST and improve livestock health.

Treatment of posterior circulation strokes by mechanical thrombectomy with a stent-retriever: a retrospective observational study at a single center. / Tratamiento del ictus de circulación posterior mediante trombectomía mecánica con stent-retriever: un estudio observacional, monocéntrico y retrospectivo.

OBJECTIVES: To determine the rate of recanalization, functional outcome at three months, and independent prognostic factors in patients with posterior circulation strokes treated with stent-retrievers and to compare these results with those of patients in an earlier series treated with "classical methods". MATERIAL AND METHODS: This was a retrospective study of consecutive patients with posterior circulation strokes treated with stent-retrievers at our center between December 1, 2011 and May 1, 2018. The main outcome variables were the rate of recanalization according to the Thrombosis in Cerebral Infarction (TICI) scale and functional independence score 90 days after treatment according to the modified Rankin Scale (mRS). We analyzed demographics, cerebrovascular risk factors, clinical findings, and probable origin. Descriptive statistics and a binary logistic regression model were used to analyze the data. RESULTS: We included 75 patients: 27 treated with "classical methods" and 48 treated with stent-retrievers (10 women; mean age, 63.9 years; median National Institute of Health Stroke Score, 15.8 (IQR 9-25); median Glasgow Coma Scale (GCS), 9.1 (IQR 6-14,5). TICI 2b-3 recanalization was achieved in 46 (95.8%) patients treated with stent-retrievers and in 15 (55.6%) patients treated with "classical methods" (p<0.0001). No significant differences were observed in the rate of patients achieving mRS 0-2 at 90 days (19 (39.6%) of those treated with stent-retrievers vs. 6 (22.2%) of those treated with "classical methods"). Mortality was lower among patients treated with stent-retrievers (14 (29.2% vs. 15 (55.6%) in those treated with "classical methods", p=0.024). GCS score was independently associated with mRS at 90 days (OR:0.67; 95%CI:0.5-0.91; p=0.01). CONCLUSIONS: In patients with posterior circulation infarcts, treatment with stent-retrievers achieved high rates of recanalization and functional independence at 90 days. The rate of complications was similar to those reported in other studies. GCS is an independent predictor of functional independence at 90 days.

Safety assessment of a lyophilized biomass of Tetraselmis chuii (TetraSOD®) in a 90 day feeding study.

TetraSOD® is a powder of the lyophilized biomass of Tetraselmis chuii strain CCFM03, a marine microalga with a history of use as feed in the aquaculture industry. Recently, algae including T. chuii have been investigated for their potential use in human food. However, published toxicology studies addressing the safety of T. chuii as a food ingredient are not available. To address this issue, the toxicity of TetraSOD® was evaluated using a 90-day oral toxicology study in rats following the Organisation for Economic Co-operation and Development (OECD) test guideline 408. No treatment-related mortality or clinical signs were noted with TetraSOD® at doses of 625, 1667, or 2500 mg/kg/day. Additionally, no adverse effects on haematology, blood biochemistry, organ weights, gross or histopathology were observed. The Non Observed Adverse Effect Level (NOAEL) for TetraSOD® is greater than the highest tested dose of 2500 mg/kg/day.

Dose-dependent antioxidant responses and pathological changes in tenca (Tinca tinca) after acute oral exposure to Microcystis under laboratory conditions.

The effects of cyanobacterial cells containing microcystins (MCs), toxins from cyanobacteria, on oxidative stress biomarkers from liver and kidney of Tenca fish (Tinca tinca) were investigated under laboratory conditions. Moreover, a histopathological study of liver, kidney, heart and intestine tissues was performed. Fish were orally exposed to cyanobacterial cells dosing 0, 5, 11, 25 and 55 microg MC-LR/fish mixed with the food. Results showed a dose-dependent decrease of superoxide dismutase (SOD) activity, and also of catalase (CAT) in the liver. Glutathione levels and protein oxidation, however, were not altered by the exposure to the cyanobacterial material. The microscopic study revealed tissue alterations even at the lower cyanobacterial cells doses. Onion-like hepatocytes in the liver, glomerulopathy in the kidney, loss of myofibrils in the heart and vacuolated enterocytes in the gastrointestinal tract were the main changes observed. These findings suggest that this fresh water fish can be adversely affected by cyanobacterial blooms in their natural habitats.

Incidence, prognosis, and prediction of haemorrhagic transformation after revascularisation for stroke. / Incidencia, pronóstico y predicción de la transformación hemorrágica tras el tratamiento revascularizador del ictus.

INTRODUCTION: Haemorrhagic transformation is a major complication of acute ischaemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial haemorrhage (ICH) after revascularisation therapy. METHODS: We conducted a retrospective, single-centre study including 235 patients with AIS who underwent intravenous recombinant tissue plasminogen activator (IV-rtPA) therapy and/or endovascular treatment. A binary logistic regression model was used to determine the variables associated with ICH, parenchymal haematomas (PH), modified Rankin Scale (mRS) scores, and mortality. RESULTS: ICH was detected in 57 (30 with PH) of 183 patients included. Mechanical thrombectomy, either alone (OR 3.3 [1.42-7.63], P=.005) or in combination with IV-rtPA (OR 3.39 [1,52-7.56], P=.003), was associated with higher risk of ICH, while higher Alberta Stroke Program Early CT scores (OR 0.71 [0.55-0.91], P=.007) were associated with lower risk. Patients with older age (OR 1.07 [1.02-1.13], P=.006) and occlusion of the terminal branch of the internal carotid artery (OR 4.03 [1.35-11.99], P = .012) had a higher risk of PH, while the use of IV-rtPA alone (OR 0.24 [0.08-0.68], P=.008) was associated with lower risk of PH. Only PH was associated with disability as measured by the mRS (OR 3.2 [1.17-8.76], P=.02) and higher mortality (OR 5.06 [1.65-15.5], P=.005). CONCLUSIONS: Greater understanding about the predictors of ICH, mRS scores, and mortality could enable better selection of patients and treatments.

Spontaneous trichoepithelioma in a laboratory mouse: gross, microscopic and immunohistochemical findings.

A spontaneous trichoepithelioma occurred in a Swiss OF1 outbred, four-month-old, intact, nulliparous female mouse from a breeding colony. At necropsy, the tumour was a single, well-delineated mass measuring 4.2 cm in major diameter, located in the thoracic region and had an intact haired surface. The regional lymph nodes were not enlarged and no other abnormalities were found. Microscopically, it was composed of a random admixture of budding epithelial islands and cystic structures variable in size. The epithelial islands were composed of basaloid cells. The cystic structures were lined by squamous epithelium with or without a granular cell layer and contained lamellar or amorphous keratin, as well as wide areas of matrical keratinization (ghost cells) with or without a peripheral layer of basaloid cells and calcified contents. Mitotic activity of basaloid cells was moderate to high, but nuclear or mitotic atypia were not observed. High and low molecular weight cytokeratins, profilaggrin and involucrin expression were observed in the tumour. The immunohistochemical profile of this rare type of tumour of the skin of mice, which includes a first-time description of involucrin expression, confirms the histological evidence of differentiation towards more than one segment of follicular epithelium.

A subchronic 90-day oral toxicity study of Origanum vulgare essential oil in rats.

Oregano essential oil (Origanum vulgare L. virens) (OEO) is being used in the food industry due to its useful properties to develop new active packaging systems. In this concern, the safety assessment of this natural extract is of great interest before being commercialized. The European Food Safety Authority requests different in vivo assays to ensure the safety of food contact materials. One of these studies is a 90 days repeated-dose oral assay in rodents. In the present work, 40 male and 40 female Wistar rats were orally exposed to 50, 100 and 200 mg/kg body weight (b.w.) OEO during 90 days following the OECD guideline 408. Data revealed no mortality and no treatment-related adverse effects of the OEO in food/water consumption, body weight, haematology, biochemistry, necropsy, organ weight and histopathology. These findings suggest that the oral no-observed-adverse-effect level (NOAEL) of this OEO is 200 mg/kg b.w. in Wistar rats, the highest dose tested. In conclusion, the use of this OEO in food packaging appears to be safe based on the lack of toxicity during the subchronic study at doses 330-fold higher than those expected to be in contact consumers in the worst scenario of exposure.

[Hypercoagulable state due to acquired protein C resistance, harbinger of colonic neoplasm?]. / Hipercoagulabilidad debida a resistencia adquirida a la proteína C activada: primer signo de neoplasia de colon?

Hereditary activated protein C resistance (aPCR) has been identified as an important risk factor for the occurrence of thromboembolic events. It is most frequently hereditary, and caused by a point mutation in factor V, named Factor V Leiden (FVL), which renders it resistant to the anticoagulant action of circulating protein C. However, aPCR can also be found in absence of FVL (acquired aPCR), associated to lupus anticoagulant, pregnancy or neoplasms. We report a case of deep venous thrombosis (DVT) in a 54 year-old woman, with no digestive symptoms and negative screening for biochemical tumor markers, who presented with DVT from FVL-negative aPCR, one year before being diagnosed of colonic adenocarcinoma. Once complete remission of the carcinoma was reached, aPCR returned to normal values. In thrombophilia screening studies, the finding of aPCR may be caused by acute-phase reactants or neoplastic processes, and therefore require evolutive evaluation and genetic search for FVL.

Incidencia, pronóstico y predicción de la transformación hemorrágica tras el tratamiento revascularizador del ictus / Incidence, prognosis, and prediction of haemorrhagic transformation after revascularisation for stroke

Introducción: La transformación hemorrágica es una complicación importante del ictus isquémico agudo (IIA). El propósito del trabajo es analizar el impacto clínico y los factores predictores de las hemorragias intracraneales (HIC) tras terapia revascularizadora.MétodosAnálisis retrospectivo monocéntrico de 235 pacientes con IIA tratados mediante trombólisis intravenosa (TIV) o tratamiento endovascular (TE). Se ha realizado un modelo de regresión logística binaria para determinar los factores asociados con las HIC, las hemorragias parenquimatosas (HP), la escala mRS y la mortalidad.ResultadosDe los 183 pacientes incluidos, 57 tuvieron HIC (30 HP). El TE mecánico (OR 3,3 [1,42-7,63], p = 0,005) y la TIV junto con TE mecánico (OR 3,39 [1,52-7,56], p = 0,003) se han asociado a mayor riesgo de HIC, mientras que valores altos de ASPECTS (OR 0,71 [0,55-0,91], p = 0,007) se han asociado a menor riesgo. Mayor edad (OR 1,07 [1,02-1,13], p = 0,006) y la oclusión de la carótida interna terminal (OR 4,03 [1,35-11,99], p = 0,012) han sido factores predictores de HP, mientras que haber recibido TIV exclusivamente (OR 0,24 [0,08-0,68], p = 0,008) se ha asociado con menor riesgo. Solo las HP se han asociado a valores invalidantes de mRS (OR = 3,2 [1,17-8,76], p = 0,02) y mayor mortalidad (OR 5,06 [1,65-15,5], p = 0,005).ConclusionesUna mejor comprensión de los factores predictores de HIC, mRS y mortalidad puede permitir una mejor selección de pacientes y tratamientos. (AU)

Introduction: Haemorrhagic transformation is a major complication of acute ischaemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial haemorrhage (ICH) after revascularisation therapy.MethodsWe conducted a retrospective, single-centre study including 235 patients with AIS who underwent intravenous recombinant tissue plasminogen activator (IV-rtPA) therapy and/or endovascular treatment. A binary logistic regression model was used to determine the variables associated with ICH, parenchymal haematomas (PH), modified Rankin Scale (mRS) scores, and mortality.ResultsICH was detected in 57 (30 with PH) of 183 patients included. Mechanical thrombectomy, either alone (OR 3.3 [1.42-7.63], P=.005) or in combination with IV-rtPA (OR 3.39 [1,52-7.56], P=.003), was associated with higher risk of ICH, while higher Alberta Stroke Program Early CT scores (OR 0.71 [0.55-0.91], P=.007) were associated with lower risk. Patients with older age (OR 1.07 [1.02-1.13], P=.006) and occlusion of the terminal branch of the internal carotid artery (OR 4.03 [1.35-11.99], P = .012) had a higher risk of PH, while the use of IV-rtPA alone (OR 0.24 [0.08-0.68], P=.008) was associated with lower risk of PH. Only PH was associated with disability as measured by the mRS (OR 3.2 [1.17-8.76], P=.02) and higher mortality (OR 5.06 [1.65-15.5], P=.005).ConclusionsGreater understanding about the predictors of ICH, mRS scores, and mortality could enable better selection of patients and treatments. (AU)

Toxicological evaluation of an Allium-based commercial product in a 90-day feeding study in Sprague-Dawley rats.

Proallium AP(®) is a commercial Allium extract intended to be used in active food packaging as the antibacterial and antioxidant effects of some organosulfur compounds are well known. However, there is little information on its toxicity and the Scientific Committee on Food (UE) requires the safety assessment of substances used in food contact materials. Thus, the aim of this study was to conduct for the first time a subchronic oral toxicity study of Proallium AP(®) with groups of 10 males and 10 females Sprague-Dawley rats fed a diet containing 0, 25, 100, 400 mg/kg/d for 90 days. No treatment-related clinical signs or mortality were noted. Besides, no treatment-related effects with regard to any of the toxicological biomarkers considered were observed, including biochemical, haematological and histopathology parameters. In conclusion, the non-observed-adverse-effect-level (NOAEL) for Proallium AP(®) in rats was determined to be a dietary dose of 400 mg/kg/d under the present experimental conditions, a value 500-fold higher than the exposure derived from its potential use in active packaging.

Acid and alkaline phosphatase activities and pathological changes induced in Tilapia fish (Oreochromis sp.) exposed subchronically to microcystins from toxic cyanobacterial blooms under laboratory conditions.

The effects of microcystins (MCs) from cyanobacterial cells on the enzymatic activities of acid and alkaline phosphatases (ACP and ALP) from liver, kidney and gill tissues, and the histopathological changes in freshwater Tilapia fish (Oreochromis sp.) were investigated under laboratory conditions. Fish were exposed to cyanobacterial cells (60.0 microg MC-LR/fish per day) through their diet at different exposure times (14 and 21 days). The cells were fed to the fish in two types of oral administration: mixed with a commercial fish food or crushed into a commercial fish food so that the toxins were released. ACP and ALP activities changed in response to MCs in a time-dependent manner, and these changes were more prominent in liver and kidney. The way the MCs were administered had no influence on the biochemical parameters. Similarly, the most severe histopathological changes were observed in the same two organs, although the gills and intestines were also affected. The parenchymal architecture of the liver was dissolved, and round hepatocytes with the appearance of pyknotic nuclei were detected. Kidney lesions consisted of the dilation of Bowman's space and necrotic epithelial cells with pyknotic nuclei in the tubules. These findings suggest that low and repeated doses of MC-LR from cyanobacterial cells induce toxicity in tilapia fish although no adverse effects were detected.

Effect of pentazocine on the evoked potentials recorded in the primary somesthetic cortical areas of guinea pigs.

The influence of pentazocine on the evoked potentials registered in the primary somesthetic cortical area in guinea pigs under pentobarbital anesthesia was studied. The stimulation was applied in the contralateral lip and the evoked cortical responses from different zones on the cortex stereotaxically localized were registered. Pentazocine (5-10 mg/kg i.v.) induced a significant increase in the latency of the evoked potentials as compared with controls. Since morphine does not modify these potentials, the effect of pentazocine is interpreted as being a direct one on the primary pain pathway.