Toxic Pattern Research Articles

Thallium Toxicity in Caenorhabditis elegans: Involvement of the SKN-1 Pathway and Protection by S-Allylcysteine.

Monovalent thallium (Tl+) is a cation that can exert complex neurotoxic patterns in the brain by mechanisms that have yet to be completely characterized. To learn more about Tl+ toxicity, it is necessary to investigate its major effects in vivo and its ability to trigger specific signaling pathways (such as the antioxidant SKN-1 pathway) in different biological models. Caenorhabditis elegans (C. elegans) is a nematode constituting a simple in vivo biological model with a well-characterized nervous system, and high genetic homology to mammalian systems. In this study, both wild-type (N2) and skn-1 knockout (KO) mutant C. elegans strains subjected to acute and chronic exposures to Tl+ [2.5-35μM] were evaluated for physiological stress (survival, longevity, and worm size), motor alterations (body bends), and biochemical changes (glutathione S-transferase regulation in a gst-4 fluorescence strain). While survival was affected by Tl+ in N2 and skn-1 KO (worms lacking the orthologue of mammalian Nrf2) strains in a similar manner, the longevity was more prominently decreased in the skn-1 KO strain compared with the wild-type strain. Moreover, chronic exposure led to a greater compromise in the longevity in both strains compared with acute exposure. Tl+ also induced motor alterations in both skn-1 KO and wild-type strains, as well as changes in worm size in wild-type worms. In addition, preconditioning nematodes with the well-known antioxidant S-allylcysteine (SAC) reversed the Tl+-induced decrease in survival in the N2 strain. GST fluorescent expression was also decreased by the metal in the nematode, and recovered by SAC. Our results describe and validate, for the first time, features of the toxic pattern induced by Tl+ in an in vivo biological model established with C. elegans, supporting an altered redox component in Tl+ toxicity, as previously described in mammal models. We demonstrate that the presence of the orthologous SKN-1 pathway is required for worms in evoking an efficient antioxidant defense. Therefore, the nematode represents an optimal model to reproduce mammalian Tl+ toxicity, where toxic mechanisms and novel therapeutic approaches of clinical value may be successfully pursued.

Comparative cyto- and genotoxicity assessment of glyphosate and glyphosate-based herbicides in human peripheral white blood cells

Glyphosate is the most heavily applied active compound of agricultural pesticides. It is solely used in more than 750 different glyphosate-based herbicide formulations (GBHs) that also contain other substances, mostly presumed as inert by regulatory agencies. The toxicity of formulations is currently assessed substance by substance, neglecting possible combined effects in mixtures and many of the findings regarding the toxic effects of glyphosate and GBHs to human cells are inconsistent. This is the first study to investigate and compare the cyto- and genotoxic potential of the active ingredient glyphosate and GBHs in human mononuclear white blood (HMWB) cells.HMWB cells were treated for 4 h at 37 °C with increasing concentrations (1–1000 μM) of glyphosate alone and in three GBHs (Roundup Mega, Fozat 480 and Glyfos) to test cytotoxic effect with fluorescent colabelling and genotoxic effect with comet assay. In addition, each concentration was tested with and without metabolic activation using human liver S9 fraction.We found that glyphosate alone does not induce significant cytotoxicity and genotoxicity over the tested concentration range. Contrarily, GBHs induced statistically significant cell death from 250 μM (Roundup Mega and Glyfos) and 500 μM (Fozat 480), as well as statistically significant increase of DNA damage from 500 μM (Roundup Mega and Glyfos) and 750 μM (Fozat 480); however, the latter observation may not be explained by direct DNA injuries, rather due to the high level of cell death (>70%) exerted by the formulations. Metabolic activation significantly increased the DNA damage levels induced by Glyfos, but not of the other GBHs and of glyphosate.The differences observed in the toxic pattern of formulations and the active principle may be attributed to the higher cytotoxic activity of other ingredients in the formulations or to the interaction of them with the active ingredient glyphosate. Hence, further investigation of formulations is crucial for assessing the true health risks of occupational and environmental exposures.

Risk factors for death and survival in paraneoplastic pemphigus associated with hematologic malignancies in adults

Paraneoplastic pemphigus (PNP) occurs more often in patients with hematologic malignancies (HMs) than in patients with solid cancer. Lung bronchiolitis obliterans (BO) is a severe complication of PNP. To determine the precise clinical and biologic features of HM-associated PNP and identify factors associated with mortality and survival. Systematic review of previously described cases of PNP associated with HMs. A total of 144 patients were included. The HMs were non-Hodgkin lymphoma (52.78%), chronic lymphocytic leukemia (22.92%), Castleman disease (18.60%), and other underlying hematologic malignancy (5.70%). The mortality rate was 57%, and most deaths occurred within the first year after the diagnosis of PNP. Multivariate analysis showed that (1) the presence of antienvoplakin antibodies and BO were significantly associated with death, and (2) a toxic epidermal necrolysis-like clinical pattern, bullous pemphigoid-like clinical pattern, and BO were significantly associated with decreased survival. Only case reports with sufficient mortality data were included. PNP associated with HM has a high mortality rate. The toxic epidermal necrolysis-like and BO-associated forms are independent survival factors in PNP associated with HMs.

Thallium-Induced Toxicity in Rat Brain Crude Synaptosomal/Mitochondrial Fractions is Sensitive to Anti-excitatory and Antioxidant Agents.

The mechanisms by which the heavy metal thallium (Tl+) produces toxicity in the brain remain unclear. Herein, isolated synaptosomal/mitochondrial P2 crude fractions from adult rat brains were exposed to Tl+ (5-250μM) for 30min. Three toxic endpoints were evaluated: mitochondrial dysfunction, lipid peroxidation, and Na+/K+-ATPase activity inhibition. Concentration-response curves for two of these endpoints revealed the optimum concentration of Tl+ to induce damage in this preparation, 5μM. Toxic markers were also estimated in preconditioned synaptosomes incubated in the presence of the N-methyl-D-aspartate receptor antagonist kynurenic acid (KYNA, 50μM), the cannabinoid receptor agonist WIN 55,212-2 (1μM), or the antioxidant S-allyl-L-cysteine (SAC, 100μM). All these agents prevented Tl+ toxicity, though SAC did it with lower efficacy. Our results suggest that energy depletion, oxidative damage, and Na+/K+-ATPase activity inhibition account for the toxic pattern elicited by Tl+ in nerve terminals. In addition, the efficacy of the drugs employed against Tl+ toxicity supports an active role of excitatory/cannabinoid and oxidative components in the toxic pattern elicited by the metal.

The effect of WIN 55,212-2 suggests a cannabinoid-sensitive component in the early toxicity induced by organic acids accumulating in glutaric acidemia type I and in related disorders of propionate metabolism in rat brain synaptosomes

Several physiological processes in the CNS are regulated by the endocannabinoid system (ECS). Cannabinoid receptors (CBr) and CBr agonists have been involved in the modulation of the N-methyl-d-aspartate receptor (NMDAr) activation. Glutaric (GA), 3-hydroxyglutaric (3-OHGA), methylmalonic (MMA) and propionic (PA) acids are endogenous metabolites produced and accumulated in the brain of children affected by severe organic acidemias (OAs) with neurodegeneration. Oxidative stress and excitotoxicity have been involved in the toxic pattern exerted by these organic acids. Studying the early pattern of toxicity exerted by these metabolites is crucial to explain the extent of damage that they can produce in the brain. Herein, we investigated the effects of the synthetic CBr agonist WIN 55,212-2 (WIN) on early markers of GA-, 3-OHGA-, MMA- and PA-induced toxicity in brain synaptosomes from adult (90-day-old) and adolescent (30-day-old) rats. As pre-treatment, WIN exerted protective effects on the GA- and MMA-induced mitochondrial dysfunction, and prevented the reactive oxygen species (ROS) formation and lipid peroxidation induced by all metabolites. Our findings support a protective and modulatory role of cannabinoids in the early toxic events elicited by toxic metabolites involved in OAs.

Toxic potencies of metabolite(s) of non-cylindrospermopsin producing Cylindrospermopsis raciborskii isolated from temperate zone in human white cells

Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) has worldwide distribution and is well known for producing the toxic alkaloid, cylindrospermopsin (CYN). Strains unable to synthesize this compound but potentially toxic were recently identified in Europe. Here, for the first time the effect of cell-free extracts of a non-CYN-producing strain of C. raciborskii was studied in human cells (neutrophils and lymphocytes) isolated from healthy donors. The observed effects were compared to those induced by CYN (1.0–0.01μgmL−1). Short-term (1h) extract treatments resulted in altered viability of cells demonstrated by increased necrosis and apoptosis in neutrophils and elevated apoptosis in lymphocytes. CYN did not induce similar effects, regardless of the toxin concentration. Exposure of T-lymphocytes to 100% C. raciborskii extract in isolated and whole-blood 72h cultures resulted in decrease of proliferation by 20.6% and 32.5%, respectively. In comparison, exposure to 1.0μgmL−1 of CYN caused lymphocytes proliferation to be inhibited by 91.0% in isolated cultures and 56.5% in whole-blood assay. Significant antiproliferative properties were also found for 0.1μgmL−1 of CYN in whole-blood culture. From the results we conclude that strains occurring in temperate zones may pose a threat to human health through the production of hitherto unknown metabolites that reveal a toxic pattern different to that of CYN. At the same time our study demonstrates that CYN is a powerful but slowly-acting toxin in human immune cells.

Dynamic of neurochemical alterations in striatum, hippocampus and cortex after the 6-OHDA mesostriatal lesion

Immediate neurochemical alterations produced by 6-OHDA could explain the general toxic pattern in the central nervous system. However, no evidences describe the effects of 6-OHDA on early changes of neurotransmitters in rats’ striatum, cortex and hippocampus. In our study, unilateral 6-OHDA injection into medial forebrain bundle (MFB) was used in rats, then five neurotransmitters were analyzed at 3, 6, 12, 24, 48 and 72h, respectively. Results showed that 6-OHDA injection caused a sharp decline of striatal dopamine (DA) levels in the first 12h followed by a further reduction between 12 and 48h. However, striatal levels of homovanillic acid (HVA) were stable in the first 12h and showed a marked reduction between 12 and 24h. Striatal levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) decreased linearly for 72h, whereas levels of norepinephrine (NE) showed a slight reduction in the first 48h, and returned back to normal afterwards. Striatal HVA/DA ratio increased significantly in the first 12h, but 5-HIAA/5-HT ratio showed a sharp increase between 12 and 72h. Besides, neurochemical alterations were also found in hippocampus and cortex, and the correlations of neurotransmitters were analyzed. Our study indicated that NE system had little influence in the early phase of 6-OHDA injection, moreover, early neurochemical alterations were involved with striatum, hippocampus and cortex.

The neuronal membrane as a key factor in neurodegeneration

The neuronal membrane as a key factor in neurodegeneration

Selenium-induced antioxidant protection recruits modulation of thioredoxin reductase during excitotoxic/pro-oxidant events in the rat striatum

Selenium (Se) is a crucial element exerting antioxidant and neuroprotective effects in different toxic models. It has been suggested that Se acts through selenoproteins, of which thioredoxin reductase (TrxR) is relevant for reduction of harmful hydroperoxides and maintenance of thioredoxin (Trx) redox activity. Of note, the Trx/TrxR system remains poorly studied in toxic models of degenerative disorders. Despite previous reports of our group have demonstrated a protective role of Se in the excitotoxic/pro-oxidant model induced by quinolinic acid (QUIN) in the rat striatum (Santamaría et al., 2003, 2005), the precise mechanism(s) by which Se is inducing protection remains unclear. In this work, we characterized the time course of protective events elicited by Se as pretreatment (Na2SO3, 0.625mg/kg/day, i.p., administered for 5 consecutive days) in the toxic pattern produced by a single infusion of QUIN (240nmol/μl) in the rat striatum, to further explore whether TrxR is involved in the Se-induced protection and how is regulated. Se attenuated the QUIN-induced early reactive oxygen species formation, lipid peroxidation, oxidative damage to DNA, loss of mitochondrial reductive capacity and morphological alterations in the striatum. Our results also revealed a novel pattern in which QUIN transiently stimulated an early TrxR cellular localization/distribution (at 30min and 2h post-lesion, evidenced by immunohistochemistry), to further stimulate a delayed protein activation (at 24h) in a manner likely representing a compensatory response to the oxidative damage in course. In turn, Se induced an early stimulation of TrxR activity and expression in a time course that “matches” with the reduction of the QUIN-induced oxidative damage, suggesting that the Trx/TrxR system contributes to the resistance of nerve tissue to QUIN toxicity.

Quinolinic Acid, an Endogenous Molecule Combining Excitotoxicity, Oxidative Stress and Other Toxic Mechanisms

Quinolinic acid (QUIN), an endogenous metabolite of the kynurenine pathway, is involved in several neurological disorders, including Huntington’s disease, Alzheimer’s disease, schizophrenia, HIV associated dementia (HAD) etc. QUIN toxicity involves several mechanisms which trigger various metabolic pathways and transcription factors. The primary mechanism exerted by this excitotoxin in the central nervous system (CNS) has been largely related with the overactivation of N-methyl-D-aspartate receptors and increased cytosolic Ca2+ concentrations, followed by mitochondrial dysfunction, cytochrome c release, ATP exhaustion, free radical formation and oxidative damage. As a result, this toxic pattern is responsible for selective loss of middle size striatal spiny GABAergic neurons and motor alterations in lesioned animals. This toxin has recently gained attention in biomedical research as, in addition to its proven excitotoxic profile, a considerable amount of evidence suggests that oxidative stress and energetic disturbances are major constituents of its toxic pattern in the CNS. Hence, this profile has changed our perception of how QUIN-related disorders combine different toxic mechanisms resulting in brain damage. This review will focus on the description and integration of recent evidence supporting old and suggesting new mechanisms to explain QUIN toxicity.

Histopathological Changes Associated with Experimental Infection of Arcobacter butzleri in Albino Rats

Arcobacters are emerging food borne pathogens potentially associated with prolonged diarrhoea and occasional systemic infections but the pathogenic mechanisms of these bacteria are largely unknown. This study was designed to investigate the pathogenicity of Arcobacter isolates. Two strains of A. butzleri isolated from stool of healthy chickens were confirmed with real time PCR and tested on albino rat by giving a single oral challenge of 109cfu/ml to 65 healthy adult male rats. Five (5) uninfected animals were used as control. Diarrheoal illness occurred in all rats from the fifth day and resolved from day 21 post infection, severe histopathological lesion such as hepatic necrosis, villous erosion, desquamation, matting and necrosis of the segments of small intestine was also observed. In this study, the toxic ileitis necrosis pattern of pathology in the gut of experimentally infected rats could be an indication of observed persistent watery diarrhea associated with the clinical presentation of Arcobacter infection in humans. The pathology of A. butzleri in albino rats had not been previously described, and it appears that the present study is the first report in Nigeria. It may therefore be useful for further investigation.

RETRACTED: On the early toxic effect of quinolinic acid: Involvement of RAGE

Quinolinic acid (QUIN)-induced toxicity is characterized by N-methyl- d-aspartate receptors over-activation, excitotoxicity and oxidative damage. The characterization of toxic cascades produced by QUIN during the first hours after its striatal infusion is relevant for understanding toxic mechanisms. The role of the receptor-for-advanced-glycation-end-products (RAGE) in the early toxic pattern induced by QUIN was evaluated. RAGE expression – assessed by Western blot analysis and immunofluorescence – was enhanced in the striata of QUIN-lesioned rats at 2 h post-lesion. QUIN-induced RAGE up-regulation was accompanied by expression of a RAGE target molecule, nuclear factor kappa B (NF-κB), and genes encoding for different enzymes. Other toxic markers linked to RAGE activation were increased by QUIN, including NO formation, premature glial response, lactate dehydrogenase leakage, mitochondrial dysfunction and nuclear condensation. Our results suggest that RAGE up-regulation may play a role in the early stages of QUIN toxicity.

Predictive value of 677C>T and 1298A>C polymorphisms of the methyletetrahydrofolate reductase (MTHFR) gene in patients treated with FOLFOX therapy

4116 Background: To test the predictive value of germinal gene polymorphisms potentially related to fluorouracil (FU) and oxaliplatin (Oxa) pharmacodynamics on toxicity, response rate, progression-free and overall survival. Methods: As part of a phase II OPTIMOX 2 trial by the GERCOR group, 117 patients were enrolled in a prospective pharmacogenetic study conducted in patients with advanced colorectal cancer, all receiving a modified FOLFOX7 therapy (65 men, 52 women, mean age 64.7, range 31–80). The maximum observed toxicity (NCI-CTCAE) for each toxic pattern, along with the best response (RECIST) were recorded. Median follow-up was 19.7 months. Gene polymorphisms relevant for FU: thymidylate synthase (TS, 28 bp repeats including the G>C mutation + 6 bp deletion in 3’UTR) and MTHFR (677C>T + 1298A>C), as well as for Oxa: GSTπ (105Ile>Val + 114Ala>Val), ERCC1 (118AAT>AAC) and ERCC2 (XPD, 751Lys>Gln) were determined (blood mononuclear cells). Results: None of the gene polymorphisms were predictive of toxicity, considered either as the maximum observed grade, or as a score equal to the sum of each toxicity pattern grade. The best response was complete response (CR) in 2 patients, partial response (PR) in 64 patients, stable disease in 47 patients and progression for 4 patients. Both the 677C>T (p = 0.022) and 1298A>C (p = 0.004) MTHFR genotypes were linked to clinical responsiveness (CR+PR, 56.4 %), with the rare allele theoretically favoring elevated reduced folate concentrations, linked to improved responsiveness. Importantly, the number of favorable MTHFR alleles (i.e. 677T and 1298C) revealed response rates of 37.1%, 53.3%, 66.1% and 80.0% in patients bearing 0, 1, 2 or 3 favorable alleles (N = 35, 15, 56 and 10), respectively (P = 0.018). None of the other genotypes were linked to treatment responsiveness. In addition, none of the analyzed polymorphisms were related to progression-free or overall survival. Conclusions: These results establish the role of MTHFR germinal polymorphism as a strong predictor of response for FOLFOX therapy in patients with advanced colorectal cancer. No significant financial relationships to disclose.

Prevalidation of in vitro continuous flow exposure systems as alternatives to in vivo inhalation safety evaluation experimentations: Outcome from MAAPHRI-PCRD5 research program

Diesel engine emission aerosol-induced toxicity patterns were compared using both in vitro (organotypic cultures of lung tissue) and in vivo experimentations mimicking the inhalation situation with continuous aerosol flow exposure designs. Using liquid media resuspended diesel particles, we show that toxic response pattern is influenced by the presence of tensioactive agent in the medium which alter particle-borne pollutant bioavailability. Using continuous aerosol exposure in vitro, we show that with high sulfur fuel (300 ppm) in the absence of oxidation catalysis, particulate matter was the main toxic component triggering DNA damage and systemic inflammation, while a very limited oxidant stress was evidenced. In contrast, with ultra-low sulfur fuel in the presence of strong diesel oxidation catalysis, the specific role of particulate matter is no longer evidenced and the gas phase then becomes the major component triggering strong oxidant stress, increased NO 2 being the most probable trigger. In vivo, plasma tumor necrosis factor alpha (TNFalpha), lung superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activity levels varied in agreement with in vitro observations. Diesel emission treatment with oxycat provokes a marked systemic oxidant stress. Again NO 2 proved to account for a major part of these impacts. In conclusion, similar anti-oxidant responses were observed in in vitro and in vivo experiments after diesel emission aerosol continuous flow exposures. The lung slice organotypic culture model-exposed complex aerosol appears to be a very valuable alternative to in vivo inhalation toxicology experimentations in rodents.

Randomised prospective phase II study of combination chemotherapy epidoxorubicin, cisplatin, 5-FU (ECF) versus epidoxorubicin, cisplatin, capecitabin (ECX) in patients with advanced or metastatic gastric cancer

4571 Background: In phase II studies ECF with 5- FU inf. resulted in response rates (RR) > 50 %. Despite high responses the potential drawback of ECF may be the poor patient’s (pts) acceptability of the indwelling catheter and external infusion pump and related complications: sepsis, catheter-related infections, shoulder pain, thrombosis and pneumothorax. Capecitabin can maintain a constant level of 5- FU without complications and inconvenience associated with central venous access. The aim was to compare the efficacy and safety ECF versus ECX. Secondary endpoint was overall survival. Methods: Pts with histological proven, previously untreated advanced or metastatic gastric cancer, >18 years, ECOG performance status 0- 2 and adequate organ and hematological function were randomized to ECF or ECX. In ECF epidoxorubicin 50 mg/m2 and cisplatin 60 mg/m2 were administrated on day 1 by i.v., 5- FU 200 mg/m2/day was administrated by cont. inf. day 1- 14 of each cycle. Cycle was repeated every 3 weeks. In ECX epidoxorubicin 50 mg/m2 and cisplatin 60 mg/m2 were administrated on day 1 by i.v., capecitabin 825 mg/m2 twd was administrated orally day 1- 14. Cycle was repeated every 3 weeks. Results: Seventy- one pts were enrolled in this study between Jan 03 to Dec 05. Male 80 %, median age 56 yrs (40- 77). Thirty pts received ECF and 41 pts received ECX . All pts were assessable for responses and toxicity. The overall clinical RR were 45 % including 12.9 % partial responses (PR) and 6.4 % complete responses (CR) in ECF group and 69 % including 21.4 % PR and 4.7 % CR in ECX group. Median OS and TTP were 8.8 months (mos) ± 7.8 and 6.0 mos ± 4.4 in ECF group and 10.5 mos ± 7.2 and 7.0 mos ± 4.6 in ECX group respectively. The most frequent grade ¾ side effects graded according to CTCAE - 3 were fatigue - 20 % in ECF group and 19.5 % in ECX group, hematological (neutropenia) - 16 % in ECF group and 4.8 % in ECX group, nausea - 10 % in ECF group and 7.3 % in ECX group, diarrhea - 2.4 % in ECX group, hand- foot syndrome - 2.4 % in ECX group. Conclusions: ECX is at least effective as ECF with less toxic pattern and more convenient for pts and could replace ECF in first- line therapy in pts with advanced or metastatic gastric cancer. No significant financial relationships to disclose.

Human poisoning in Thailand: The Ramathibodi Poison Center's experience (2001–2004)

Objective. To identify poisoning and toxic exposure pattern, severity, and clinical outcome in Thailand during 2001 to 2004. Method. This is a prospective study. All inquiries were registered, followed up, and verified. Interlocutors, poisons, patients' profiles, severity, and medical outcome after exposure or poisoning were analyzed. Results. A total 14,428 events was suspected as human poisoning or exposure. After follow-up and verification, 98.9% were confirmed as poisoning or poison exposure. These involved 15,016 patients and accounted for 6.0 per 100,000 populations per year. The vast majority of calls (92.4%) were from physicians. Pesticides, household products, and pharmaceutical products were the most common poisons involved in human exposure, which were 41.5%, 19.5%, and 18.9%, respectively. Patients aged 0–6 years, teenagers and adults with 20–29 years of age had the highest rates of exposure, which were 33.0, 24.5, and 10.5 exposures per 100,000 per year, respectively. Unintentional accidental exposure is the major reason of exposure in children, but intentional suicide was the main reason of exposure in teenagers and adults. The death rate of all exposure was 5.5%. Pesticides cause more severe clinical course and the highest death rate (10.0%). Conclusion. Features of poisoning in Thailand were different from those in Western countries. Pesticide poisoning was the major problem in Thailand. Intentional suicide was the major circumstance of poison exposure in adults, but accidental exposure was the major reason of exposure in children.

Metabolism and toxicity of diisopropylnaphthalene as compared to naphthalene and monoalkyl naphthalenes: a minireview

Detailed knowledge does exist on the toxicological safety of diisopropylnaphthalene (DIPN). Its metabolism is the key to understanding its very low toxicity. The metabolic pathway of 2,6-DIPN in rats was found to proceed almost exclusively through oxidation of the isopropyl side-chain. This has decisive toxicological implications, which could be demonstrated by comparing the lung-specific toxic effects of naphthalenes in mouse: the lack of ring oxidation correlates well with lack of lung toxicity while, vice versa, the extent of enzymatic oxidative attack at the aromatic ring structure results in a toxic pattern that is observed with naphthalene and its monomethyl derivatives. It is concluded that DIPN and other highly alkylated naphthalenes are supposed to offer favourable safety properties because of their `alkyl character' and therefore must not be compared with the toxic properties of naphthalene and closely related aromatic compounds.

Aluminum-Induced Genes (Induction by Toxic Metals, Low Calcium, and Wounding and Pattern of Expression in Root Tips).

We have investigated the response of four Al-induced genes (wali1, -3, -4, and -5) from wheat (Triticum aestivum L.) to other stresses. The relative transcript levels of wali1 (encoding a plant metallothionein-like protein), wali3 and wali5 (putative Bowman-Birk proteinase inhibitors), and wali4 (phenylalanine ammonialyase) increased in root tips of wheat after 2-d treatments with toxic levels of all other metals tested (Cd, Fe, Zn, Cu, Ga, In, and La). The expression levels of wali1, -3, -4, and -5 also increased in the root tips of plants grown in the presence of low levels of Ca (10[mu]M). The transcript levels of wali1, -3, and -5 increased in wounded leaf and root tissue, whereas the transcript levels of wali4 increased only in wounded leaves. The site of expression of wali1, -3, and -5 in root tips was identified using in situ hybridization. wali1 was expressed predominantly in the meristematic tissue of the root tip, whereas wali3 and wali5 were expressed predominantly in the cortical tissue of the root. Some changes in the site of expression of these genes were evident in the roots of Al-treated plants.

Biologic response modifiers: The interferon alfa experience

The effects and toxicities of interferon alfa are described, and the role of the pharmacist in making decisions and providing education about biologic response modifiers (BRMs) is discussed. Interferons have both direct antitumor activity and extensive effects on the immune system. Two recombinant interferon alfa products--interferon alfa-2a and interferon alfa-2b are available commercially. Indications in FDA-approved labeling for interferon alfa include the treatment of hairy-cell leukemia, acquired immunodeficiency syndrome-related Kaposi's sarcoma, and genital warts; however, it also is being used successfully against early chronic myelogenous leukemia, low-grade non-Hodgkin's lymphoma, cutaneous T-cell lymphoma, and previously untreated multiple myeloma. Other malignancies that respond to treatment with interferon alfa are malignant melanoma, ovarian carcinoma, and renal cell carcinoma. The toxic pattern of interferon alfa consists of flu-like symptoms, which are seen at all doses, on all schedules, and in virtually all patients. After repeated dosing, the chronic toxicities of anorexia, weight loss, and malaise and fatigue may develop. Myelosuppression, central nervous system toxicity, increased hepatic enzyme concentrations, nausea and vomiting, and cardiovascular toxicity also are possible. Serum neutralizing antibodies may be formed during therapy; this phenomenon may affect the clinical outcome. Numerous BRMs are being investigated for clinical use, and pharmacists must become conversant in the issues that surround these agents. Areas in which pharmacist involvement and knowledge are important include overall cost, product similarities and differences, dosing and scheduling, drug delivery systems, ways to minimize waste, adverse effects and their management, drug interactions, storage requirements, differences in production and purification techniques among manufacturers, and education of patients and staff.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation of different protein kinase activities in the human thyroid gland. Evidence for an abnormal form in hyperfunctioning adenomas

Protein kinases from normal and from hyperfunctioning “toxic” adenoma human thyroid tissue were analyzed by DE 52 cellulose chromatography. In normal, as well as in toxic adenoma, three peaks of histone kinase activity were eluted. The first two corresponded to types I and II cAMP dependent histone kinases. The third, eluting at 350 mM, was cAMP independent. Two peaks of phosvitin kinase (125 mM and 450 mM) and one of casein kinase (125 mM) activities were also observed. The toxic adenoma elution pattern differed from normal by the presence of an additional peak of histone kinase activity which coeluted with the second peak of phosvitin kinase (450 mM). This additional histone kinase activity was cAMP independent.