Disintegrins extracted from totonacan rattlesnake (Crotalus totonacus) venom and their anti-adhesive and anti-migration effects on MDA-MB-231 and HMEC-1 cells.

Disintegrins are low molecular weight cysteine-rich proteins (4-14 kDa) that are isolated mainly from viperid snake venom. Due to their potential as lead compounds for binding and blocking integrin receptors, snake venom disintegrins have become one of the most studied venom protein families. The aim of this study was to obtain disintegrins from C. totonacus venom and evaluate their capability to bind and block integrin receptors. The C. totonacus disintegrin fraction (totonacin) represents two disintegrin isoforms obtained from C. totonacus venom. These disintegrins showed extracellular-matrix (ECM) protein adhesion and migration inhibitory effects on MDA-MB-231 and HMEC-1 cells. Totonacin (3 µM) inhibited MDA-MB-231 cell adhesion to the ECM proteins, fibronectin, vitronectin, and laminin by 31.2, 44.0, and 32.1, respectively. Adhesion inhibition to fibronectin, vitronectin, and laminin observed on HMEC-1 cells was 42.8, 60.8, and 51%, respectively. In addition, totonacin (3 µM) significantly inhibited MDA-MB-231 and HMEC-1 cell migration (41.4 and 48.3%, respectively). Totonacin showed more potent cell adhesion inhibitory activity toward vitronectin in both cell lines. These results suggest a major affinity of totonacin toward αVß3, α8ß1, αVß5, αVß1, and αIIbß3 integrins. In addition, the inhibitory effect observed on MDA-MB-231 and HMEC-1 cell migration reinforces the evidence of an interaction between these disintegrins and αVß3 integrin, which plays a key role in migration and angiogenesis.

Attenuation of pro-inflammatory cytokines and oxidative stress by misoprostol in renal ischemia/reperfusion in rats.

The ischemia/reperfusion (I/R) process alters metabolic pathways, releasing reactive oxygen species and pro-inflammatory cytokines that cause tissue necrosis and activate cellular apoptotic pathways. Misoprostol (MSP) is a prostaglandin E1 analog that has demonstrated a cytoprotective role in the I/R process. The study objective was to evaluate the effects of MSP on the regulation of pro-inflammatory and oxidative stress mediators in an I/R-induced acute kidney injury rat model. Wistar rats were divided into 3 groups. Sham and I/R were given 1 mL/day of physiological solution; MSP+I/R was given intragastric MSP (300 µg/kg) for 3 days. For I/R and MSP+IR, the renal hilum was clamped for 45 min, followed by 15 h of reperfusion. Renal function tests, pro-inflammatory cytokines, mediators of oxidative stress, and histological analysis were evaluated. Pro-inflammatory cytokine activity was significantly attenuated in the MSP+I/R group. However, there was no statistically significant difference between Sham and MSP. Regarding antioxidant activity, MSP+I/R showed a significant decrease in these mediators compared with Sham and I/R. Histologically, scarce medullary necrosis was observed with a preserved renal cortex in the MSP group.

In vitro metabolism and toxicity assessment of toxin T-514 (Peroxisomicine A1) of Karwinskia humboldtiana in microsomes and primary cultured hepatocytes.

T-514 (Peroxisomicine A(1)) from Karwinskia humboldtiana is a dimeric hydroxyanthracenone with a highly selective cytotoxic effect on tumor cells. We evaluated the metabolism of this compound in two in vitro systems (liver microsomes and hepatocytes) and assessed the cytotoxicity of its metabolites on normal and tumor cells. Microsomes (12.5, 125 and 250 microg of protein/ml) and hepatocytes (1 x 10(6) cells/ml) were incubated with the toxin (25 microM) for 0.5, 1, 3, 6, 9, 12 and 24 h and the samples were examined using chromatographic analysis and UV spectra. Two metabolites (M1 and M2) were detected in the rat microsomes and one (M1) in the monkey microsomes. The retention times and UV spectra of the peaks were very similar to those of the toxin T-514. M1 was isolated and identified as a mixture of two isomers. The cytotoxicity of the metabolites was evaluated in Chang liver and Hep G2 cells but they did not show the selective cytotoxic effect on tumor cells seen in the original compound.

Production of reactive oxygen species by toxin T-514 of genus Karwinskia in vitro.

In the present study we have analyzed the production of reactive oxygen species by toxin T-514 of the genus Karwinskia in vitro (primary liver cell cultures and microsomes), as well as their possible role in its cytotoxicity. The role of catalase and superoxide dismutase (SOD) as defense mechanisms against oxidative stress was also studied. Freshly isolated hepatocytes or microsomes were exposed to T-514 in the presence or absence of catalase and SOD. Cytotoxicity was determined by methylthiazoltetrazolium (MTT) reduction. Oxidative stress was evaluated by the dichlorofluorescein diacetate (DCFDA) fluorescent probe and the reduction of ferricytochrome c. Exposure of hepatocytes to toxin T-514 for 2-, 4-, 6- and 24-h periods resulted in a time- and concentration-dependent increase in the suppression of mitochondrial metabolic activity. T-514 induced the production of reactive oxygen species in both hepatocytes and microsomes. Catalase and superoxide dismutase had a protective effect against the cytotoxicity of T-514 in hepatocytes and also inhibited the production of oxygen reactive species in microsomes. The results indicate that oxidative stress mediated by reactive intermediates may be a mechanism by which T-514 induces its cytotoxic effect.

Effect of meso-2,3-dimercaptosuccinic acid on urinary lead excretion in exposed men.

The efficacy of meso-2,3-dimercaptosuccinic acid (DMSA) was evaluated in workers occupationally exposed to lead (Pb; blood level >50 microg/dL). Ten men were given 600 mg of DMSA per orem daily, for five days. Pb concentrations of whole blood and urine were determined throughout therapy. Hematology analyses, blood chemistry, and urinalysis were obtained at the start of the study, at the end of the DMSA treatment, and at 72 hours after the administration of the final dose. DMSA therapy had no influence on hepatic, hematologic, or renal functions and was effective in decreasing the concentration of blood Pb in all the subjects without adverse drug reactions.

Apoptosis induction and cell cycle perturbation in established cell lines by peroxysomicine A1 (T-514).

Peroxysomicine A1, a novel potential anticancer compound induced cell death in established cell lines and in a primary culture of rat neonatal cardiomyocytes. Non-transformed cells are less sensitive to the compound than transformed cell lines. Fluorescent microscopy of dying cells stained with DNA-specific dyes revealed chromatin condensation and nuclear fragmentation as well as membrane blebbing characteristic of apoptosis. Flow cytometry of cells treated with peroxysomicine A1, demonstrated appearance of cells containing less than 2C DNA, that indicated degradation of nuclear DNA, another hallmark of apoptotic cell death. Z-VAD, a nonspecific caspase inhibitor, prevented DNA fragmentation but not cell death registered by permeabilization of cell outer membrane. Peroxysomicine A1 also inhibited proliferation of various cell lines. Flow cytometry analysis showed significant accumulation of dividing cells in G2/M phases of cell cycle indicating, most likely delay in G2. These results provide initial insight into the mechanisms of action of peroxysomicine A1 and suggest that peroxysomicine A1 is a potent inhibitor of cell proliferation and inducer of apoptosis and may be a useful antineoplastic chemotherapeutic agent.

Urinary excretion of trace elements in humans after sodium 2,3-dimercaptopropane-1-sulfonate challenge test.

OBJECTIVE: To evaluate the effects of intravenous sodium 2,3-dimercaptopropane-1-sulfonate (DMPS, Dimaval) on urinary excretion of essential trace elements in subjects who received this chelating agent as a mercury challenge test. SUBJECTS: Eleven subjects sought medical attention due to concern with the toxicity of mercury released from dental amalgam fillings. DESIGN: The subjects were given DMPS 3 mg/kg intravenously. Spot urine samples were collected 1 hour before and 1 hour after the DMPS dose for laboratory analysis. In addition to mercury, the urinary excretion of copper, zinc, selenium, magnesium, manganese, molybdenum, chromium, cobalt, and aluminum were measured. RESULTS: A significant increase in urinary excretion of mercury (3- to 107-fold) was observed after the DMPS dose. The DMPS treatment led to a 2- to 119-fold increase in copper excretion; 3- to 43.8-fold in selenium excretion; 1.6- to 44-fold in zinc excretion; and 1.75- to 42.7-fold in magnesium excretion. The excretion of manganese, chromium, cobalt, aluminium, and molybdenum remained unchanged. CONCLUSIONS: In this study, an intravenous DMPS challenge test produced a significant increase in mercury excretion and also led to an increased excretion of copper, selenium, zinc, and magnesium.

Intravenous self-administration of metallic mercury: report of a case with a 5-year follow-up.

CASE REPORT: A case of intravenous self-administration of elementary mercury is presented. The increase urinary excretion of mercury after treatment with 2,3-dimercaptopropane-1-sulfonate is reported on a 5-year follow-up. No biochemical abnormalities in hepatic or renal function nor clinical pulmonary malfunction have been detected, despite the persistence of metallic densities in the body. The only persistent symptoms are tremor and lower extremity weakness. Any long term benefits of 2,3-dimercaptopropane-1-sulfonate treatment remains to be determined.

Urinary mercury in twelve cases of cutaneous mercurous chloride (calomel) exposure: effect of sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy.

OBJECTIVE: To evaluate clinical symptoms and urinary mercury before and after chelation therapy in subjects with chronic cutaneous mercurous chloride (HgCl; calomel) exposure. SUBJECTS: Twelve women from 19-45 years who had used a facial cream which contained HgCl (5.9%) for 2 to 10 years. DESIGN: Twenty-four hour urine samples were collected for basal urine mercury. All the subjects received a 5-day cycle of oral sodium 2,3 dimercaptopropane-l-sulfonate (Dimaval capsules 100 mg) 200 mg/d on an outpatient basis. The urine mercury excretion was monitored 24 hours after the first dose and 72 hours after the last dose in eight subjects. RESULT: Exanthem and tremor were detected in two of 12 subjects. The range of urine mercury was 180 to 1876 micrograms/g creatinine. A significant increase in the urinary mercury excretion was observed in the first 24 hours after beginning sodium 2,3-dimercaptopropane-1-sulfonate. CONCLUSION: Chronic topical application of 5.9% HgCl cream was associated with clinical mercurialism in two subjects and with high urinary mercury level in all the cases. Sodium 2,3-dimercaptopropane-1-sulfonate was effective in increasing urine mercury.

Evaluation of urinary mercury excretion after administration of 2,3-dimercapto-1-propane sulfonic acid to occupationally exposed men.

The purpose of this study was to determine the clinical efficacy of 2,3-dimercapto-1-propane sulfonic acid, Na salt, on the urinary excretion of mercury as well as its possible adverse effects. Ten men with occupational mercury exposure (urinary level of 50 micrograms/g creatinine or more) were assigned to receive 2,3-dimercapto-1-propane sulfonic acid p.o. (DIMAVAL capsules, 100 mg) 300 mg/d for five days. Informed written consent was obtained from each subject. Hematology analyses, blood, chemistry, and urinalysis were obtained at the start of the study, at the end of the 2,3-dimercapto-1-propane sulfonic acid treatment and 72 hours after the administration of the final dose of 2,3-dimercapto-1-propane sulfonic acid. Twenty-four-hour urine mercury levels were closely monitored throughout therapy. All data and measurements before and during drug doses were evaluated by analyses of variance. In all subjects mean urine mercury was significantly increased (p < .05) after pre-2,3-dimercapto-1-propane sulfonic acid treatment. One subject had a moderate hypersensitivity reaction (rash) to 2,3-dimercapto-1-propane sulfonic acid but no other toxic effects were observed.

Comparison of the hepatotoxicity of toxin T-514 of Karwinskia humboldtiana and its diastereoisomer in primary liver cell cultures.

Toxin T-514 of Karwinskia humboldtiana has been demonstrated to be hepatotoxic in vivo and in vitro. Recently a diastereoisomer of T-514 has been isolated. In the present study we have evaluated and compared the in vitro hepatoxicity of the diastereoisomer of T-514 using primary cultures of rat hepatocytes. Cytotoxicity was evaluated by release of cytoplasmic enzyme lactate dehydrogenase (LDH), and mitochondrial metabolic function (MTT reduction). The diastereoisomer was shown to be almost as hepatoxic in vitro as toxin T-514.

Toxicity assessment of toxins T-514 and T-544 of buckthorn (Karwinskia humboldtiana) in primary skin and liver cell cultures.

The present study was undertaken to assess and compare the in vitro cytotoxicity of toxins T-514 and T-544 of buckthorn (Karwinskia humboldtiana) using primary cultures of rat hepatocytes and keratinocytes. Cell cultures were exposed to 6, 12, 25 and 50 microM toxins for 2-, 4-, 6- and 24-h periods. Cytotoxicity was determined by release of the cytoplasmic enzyme, lactate dehydrogenase (LDH), in culture media, methylthiazoltetrazolium (MTT) reduction and neutral red (NR) uptake. An increase in LDH leakage was observed in liver cell cultures as early as 2 h with 50 microM T-544 and with 6 microM T-514 and T-544 at 6 h and 24 h, respectively. In the NR assay the toxicity was evident at 2 h with 12 microM T-514 and T-544 and with 6 microM concentrations of both toxins at 6 h. On the other hand, a decrease in MTT reduction was detected at 4 h with 50 microM concentrations of both toxins and with 25 microM T-544 and 12 microM T-514 at 6 h and 6 microM T-514 and T-544 at 24 h. Both toxins were shown to be highly hepatotoxic; T-514 was more toxic than T-544. In the skin cell cultures, the toxicity of the toxins was not as severe and was not expressed until 12 h of exposure.

Toxicity assessment of toxins T-514 and T-544 of buckthorn (Karwinskia humboldtiana) in primary skin and liver cell cultures.

The present study was undertaken to assess and compare the in vitro cytotoxicity of toxins T-514 and T-544 of Buckthorn (Karvinskia humboldtiana) using primary cultures of rat hepatocytes and keratinocytes. Cell cultures were exposed to 6, 12, 25 and 50 microM concentrations of the toxins for 2, 4, 6 and 24-h periods. Cytotoxicity was determined by release of the cytoplasmic enzyme, lactate dehydrogenase (LDH), in culture media, methylthiazoltetrazolium (MTT) reduction and neutral red (NR) uptake. An increase in LDH leakage was observed in liver cell cultures as early as 2 h with 50 microM T-544 and with 6 microM T-514 and T-544 at 6 h and 24 h, respectively. In the NR assay the toxicity was evident at 2 h with 12 microM T-514 and T-544 and with 6 microM concentrations of both toxins at 6 h. On the other hand, a decrease in MTT reduction was detected at 4 h with 50 microM concentrations of both toxins and with 25 microM T-544 and 12 microM T-514 at 6 h and 6 microM T-514 and T-544 at 24 h. Both toxins were shown to be highly hepatotoxic; T-514 was more toxic than T-544. In the skin cell cultures, the toxicity of the toxins was not as severe and was not expressed until 12 h of exposure.

Intoxicaciones: un estudio retrospectivo en el Hospital Universitario Dr. José E. González, 1980 - 1984 / Intoxications: a retrospective study at the \"Dr. José E González\" University Hospital 1980 - 1984

Se efectuó un estudio retrospectivo de las intoxicaciones registradas en el Hospital Universitario "Dr. José E. González" (H.U.) de 1980 a 1984 en el cual se consideraron los siguientes puntos: edad y sexo del paciente, tipo y modo de intoxicación, mortalidad y total de intoxicaciones en este periodo. El ingreso total de pacientes al H.U. fue de 182,247 del cual el 0.26% (477) correspondió a intoxicaciones siendo las más frecuentes: petróleo (Kerosene), cáusticos, salicilatos, alcohol etílico y atropina. El modo de intoxicación fue accidental en un 90% de los casos e intento de suicidio en 10%. La mayoría fueron niños (70%) y un 30% adultos; 277 masculinos y 200 femeninos. La mortalidad por intoxicaciones fue de 1.25% (6 de 477 pacientes) y las substancias relacionadas con estas muertes fueron digitálicos (3), salicilatos (1), talio (1) y cáusticos (1)