NMDA Receptor Antagonist MK801 Protects Against 1-Bromopropane-Induced Cognitive Dysfunction / 神经科学通报·英文版

Occupational exposure to 1-bromopropane (1-BP) induces learning and memory deficits. However, no therapeutic strategies are currently available. Accumulating evidence has suggested that N-methyl-D-aspartate receptors (NMDARs) and neuroinflammation are involved in the cognitive impairments in neurodegenerative diseases. In this study we aimed to investigate whether the noncompetitive NMDAR antagonist MK801 protects against 1-BP-induced cognitive dysfunction. Male Wistar rats were administered with MK801 (0.1 mg/kg) prior to 1-BP intoxication (800 mg/kg). Their cognitive performance was evaluated by the Morris water maze test. The brains of rats were dissected for biochemical, neuropathological, and immunological analyses. We found that the spatial learning and memory were significantly impaired in the 1-BP group, and this was associated with neurodegeneration in both the hippocampus (especially CA1 and CA3) and cortex. Besides, the protein levels of phosphorylated NMDARs were increased after 1-BP exposure. MK801 ameliorated the 1-BP-induced cognitive impairments and degeneration of neurons in the hippocampus and cortex. Mechanistically, MK801 abrogated the 1-BP-induced disruption of excitatory and inhibitory amino-acid balance and NMDAR abnormalities. Subsequently, MK801 inhibited the microglial activation and release of pro-inflammatory cytokines in 1-BP-treated rats. Our findings, for the first time, revealed that MK801 protected against 1-BP-induced cognitive dysfunction by ameliorating NMDAR function and blocking microglial activation, which might provide a potential target for the treatment of 1-BP poisoning.

Hexabromocyclododecane-induced Genotoxicity in Cultured Human Breast Cells through DNA Damage / 生物医学与环境科学（英文）

To investigate the genotoxicity and reveal the potential toxicological mechanisms of Hexabromocyclododecane (HBCD), human breast cells HBL-100 were exposed to a sequence of HBCD concentrations (0, 5, 10, and 50 mg/L) for 24 h. With a series of zymology and molecular biology methods, we found that HBCD induced dose-dependent oxidative stress on HBL-100 DNA. As revealed in qRT-PCR, activated prognostic factor ATM down-regulated tumor suppressor gene BRCA1 and prompted DNA repair genes hOGG1 and hMTH1 expression in lower concentrations of HBCD (< 10 mg/L). However, DNA repair were inhibited as well as cell proliferation rate by higher concentrations of HBCD (50 mg/L). The results inferred that the genotoxicity of HBCD was dose-dependent and related to DNA repair pathway.

Effects of 1-bromopropane on liver and kidney functions of exposed workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effects of 1-bromopropane (1-BP) on liver and kidney functions of exposed workers.</p><p><b>METHODS</b>Occupational health situation in three 1-BP plants was investigated. Fifty-four workers from the 1-BP manufacturing line were chose to be contact group, while 42 workers from non-1-BP manufacturing line as control group. All workers underwent questionnaire survey, liver function test as well as kidney function test.</p><p><b>RESULT</b>Working years has no impact on liver and kidney functions of workers from contact group. Compared with the control, liver and kidney functions test of the two groups showed no statistical difference either.</p><p><b>CONCLUSION</b>The present investigation doesn't prove any impact of occupational 1-BP exposure on worker's liver and kidney functions.</p>

Effects of bromopropane exposure on expression of DNA methyltransferases and level of histone acetylation in testis of male rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the changes in the expression of DNA methyltransferases (DNMTs) and activities of histone acetyltransferase (HAT) and histone deacetylase (HDAC) in the testis of male rats exposed to bromopropanes (BPs).</p><p><b>METHODS</b>Twenty-seven male rats were randomly divided into three groups to be intraperitoneally injected with 1-BP,2-BP, or corn oil (as a control) for two weeks. The sperm count and morphology in the epididymis were evaluated. The mRNA expression of DNMT1, DNMT3a, and DNMT3b and activities of HAT and HDAC in the testis were measured by quantitative real-time PCR and ELISA.</p><p><b>RESULTS</b>Compared with the control group, the BP exposure groups showed significant decreased absolute and relative sperm counts; the proportion of tailless sperm increased in the 1-BP exposure group, while the proportion of sperm with abnormal heads increased in the 2-BP exposure group. The 2-BP exposure group had significantly lower mRNA expression of DNMT1, DNMT3a, and DNMT3b than the control group (P < 0.05). There were no significant differences in the activities of HAT and HDAC between the control group and 1-BP exposure group; the 2-BP exposure group showed significantly higher HAT activity than the control group (P < 0.05), but no significant difference was found in HDAC activity between them.</p><p><b>CONCLUSION</b>Exposure to 2-BP might induce abnormal DNA methylation and histone acetylation, and epigenetic regulation might play an important role in the reproductive toxicity of 2-BP.</p>

Determination of1-bromopropane in the workplace air by GC-FID / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a method for determination 1-bromopropane (1-BP) in workplace air by gas chromatography-flame ionization detector (GC-FID).</p><p><b>METHOD</b>1-bromopropane in workplace air was collected with activated charcoal tube, then desorbed by carbon disulfide and determined by GC-FID. 1-bromopropane was quantitatively measured using retention time and peak area.</p><p><b>RESULTS</b>Linear regression formula was Y = 3353.4x-10064 in a range of 2.50 ∼ 500.00 µg/ml with regression coefficient R = 0.9998. Detection limit was 0.25 µg/ml and the lowest detection concentration of 1-brmopropane in air was 0.14 mg/m(3) (at air volume 1.8L). The mean recoveries of 1-BP were between 96.8% and 102.6%, and relative standard deviation of inter and intra-assay was less than 10%. The average desorption efficiencies were between 93.2% and 104.4%. The samples in activated charcoal tube could be stably stored for 5 days at room temperature.</p><p><b>CONCLUSION</b>The method could be feasible to determine 1-bromopropane in workplace air.</p>

Effect of docosahexaenoic acid and nervonic acid on the damage of learning and memory abilities in rats induced by 1-bromopropane / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the protective effects of docosahexaenoic acid (DHA) and nervonic acid (NA) on the learning and memory abilities in rats exposed to 1-bromopropane (1-BP) and their action mechanisms.</p><p><b>METHODS</b>Forty male Wistar rats (specific pathogen-free) were randomly divided into 4 groups (n = 10 for each), i.e., solvent control group, 1-BP (800 mg/kg) group, NA (150 mg/kg) + 1-BP (800 mg/kg) group, and DHA (500 mg/kg) + 1-BP (800 mg/kg) group. The rats were given respective test substances by gavage for 7 d. The Morris water maze (MWM) test was performed from days 8 to 12 to evaluate the rats' learning and memory abilities. After MWM test, rats were sacrificed in the next day, and cerebral cortex was quickly dissected and homogenized in an ice bath. The supernatant of the obtained homogenate was collected to measure the content of glutathione (GSH) and malondialdehyde (MDA) and the activities of glutathione reductase (GR) and γ-glutamate cysteine ligase (γ-GCL).</p><p><b>RESULTS</b>The MWM spatial navigation test showed that the 1-BP group had significantly longer escape latency and significantly longer total swimming distance compared with the control group (P<0.05), while the DHA+1-BP group had significant decreases in escape latency and total swimming distance compared with the 1-BP group (P<0.05). The spatial probe test showed that the number of platform crossings was significantly greater in the DHA+1-BP group and NA+1-BP group than in the 1-BP group (P<0.05); compared with the control group, the 1-BP group had a significantly lower ratio of time spent in the zone around the platform to total time (P < 0.05), and the ratio was significantly higher in the DHA+1-BP group than in the 1-BP group (P < 0.05). Compared with the control group, the 1-BP group had a 18.1% decrease in GSH content, and DHA could significantly reverse 1-BP-induced decrease in GSH content (P < 0.05). Compared with the 1-BP group, the DHA+1-BP group and NA+1-BP group had significantly decreased MDA content (P < 0.05), the DHA+1-BP group had significantly increased GR activity (P < 0.05), and the NA+1-BP group had significantly increased γ-GCL activity (P < 0.05).</p><p><b>CONCLUSION</b>The rats exposed to 1-BP have oxidative stress in the brain and impaired cognitive function. DHA and NA can reduce 1-BP-induced cognitive function impairment in rats, possibly by increasing the activities of GR and γ-GCL and the content of GSH in the brain.</p>

Development of peripheral neuropathy rat model induced by 1-bromopropane / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the peripheral neurotoxicity of 1-bromopropane (1-BP) by developing an animal model of peripheral neuropathy through oral administration of 1-BP.</p><p><b>METHODS</b>Forty male Wistar rats were randomly and equally divided into low-dose group (200 mg/kg), medium-dose group (400 mg/kg), high-dose group (800 mg/kg), and control group. The rats in the low-dose, medium-dose, and high-dose groups were orally given 1-BP (dissolved in corn oil), while the rats in the control group were orally given an equal volume of corn oil. The oral administration (0.2 ml/100 g BW) was performed once per day, 5 days per week, for 16 consecutive weeks. Neurobehavioral indices including gait score, hindlimb grip strength, and hindlimb landing foot splay were recorded periodically. Hematological and biochemical parameters were also measured during and after 1-BP exposure.</p><p><b>RESULTS</b>The gait scores were significantly higher in the high-dose group (after 8 ∼ 16 weeks of 1-BP exposure), medium-dose group (after 14 ∼ 16 weeks of 1-BP exposure), and low-dose group (after 15 ∼ 16 weeks of 1-BP exposure) than in the control group (P < 0.05, P < 0.01). Compared with the control group, the high-dose group showed significantly decreased hindlimb grip strength after 9, 12, and 14 weeks of 1-BP exposure (P < 0.05, P < 0.01), with the hindlimbs paralyzed after 16 weeks of 1-BP exposure. After 16 weeks of 1-BP exposure, the hindlimb grip strengths of rats in the medium-dose and low-dose groups were decreased to 72.6% and 91.2% of the control value (P < 0.01, P < 0.05). Compared with the control group, the high-dose group showed significantly increased hindlimb landing foot splay after 12, 14, and 16 weeks of 1-BP exposure, and the medium-dose group showed significantly increased hindlimb landing foot splay after 14 and 16 weeks of 1-BP exposure (P < 0.05, P < 0.01). The high-dose and medium-dose groups showed significantly higher serum alanine aminotransferase (ALT) activity than the control group after 8 weeks of 1-BP exposure, and so did the low-dose group after 16 weeks of 1-BP exposure (P < 0.01).</p><p><b>CONCLUSION</b>The nervous system is sensitive to the toxic effect of 1-BP, and 1-BP exposure can induce peripheral neuropathy in rats.</p>

Levels of hexabromocyclododecane in human breast milk and the daily intake of newborns in a Shanghai hospital / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the level of hexabromocyclododecane (HBCD) in human breast milk of delivery women in a Shanghai hospital, and estimate the daily intake of newborns from breast milk.</p><p><b>METHODS</b>Forty-eight delivery women in a Shanghai suburb hospital (Class A, Grade 3) were surveyed by questionnaires, and their breast milk samples were collected from September 2006 to April 2007. All the delivery women were singleton pregnancies, excluding high blood pressure, diabetes, HIV infection and adverse medical history. Three diastereoisomers (α-HBCD, β-HBCD, γ-HBCD) were measured by the liquid chromatography-electrospray ion source-tandem mass spectrometry, and then estimated the daily intake of the newborns from the breast milk.</p><p><b>RESULTS</b>The total HBCD concentration of breast milk, which was detected in 79% (38/48) of samples, ranged from 0.11 ng/g lipid weight (lw) to 37.75 ng/g lw, with the median at 1.42 ng/g lw. The most abundant diastereoisomer was α-HBCD which detected in 77% (37/48) of samples, with a median of 1.24 ng/g lw; followed by γ-HBCD and β-HBCD, detected in 13% (6/48) and 17% (8/48) of samples respectively, whose median were both under the limit of detection (LOD). The daily intake of the newborns from the breast milk ranged from 0.71 ng/kg to 243.46 ng/kg.</p><p><b>CONCLUSION</b>The concentrations of HBCD in breast milk of delivery women in a Shanghai hospital have been in a high level, and the influence on newborns' health need to be further studied.</p>

Effects of 1-bromopropane exposure on cognitive function in rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effects of 1-bromopropane (1-BP) on the functions of learning-memory and the central cholinergic system in rats.</p><p><b>METHODS</b>Forty male Wistar rats were randomly divided into four groups: low 1-BP group (200 mg/kg), middle 1-BP group (400 mg/kg), high 1-BP group (800 mg/kg) and control group, and the exposure time was 7 days. The Morris water maze (MWM) test was applied to evaluate the learning-memory function in rats. After the MWM test, the rats were sacrificed, the cerebral cortex and hippocampus were quickly dissected and homogenized in ice bath. The activity of acetylcholine esterase (AChE) and choline acetyltransferase (ChAT) in supernatant of homogenate were detected.</p><p><b>RESULTS</b>The latency and swim path-length of rats in middle and high 1-BP groups prolonged significantly in place navigation test and the efficiency of searching strategy obviously decreased, as compared with control group (P < 0.05 or P < 0.01). In spatial probe test, the number of crossing platform in three 1-BP groups decreased significantly, as compared with control group (P < 0.05 or P < 0.01). The cortical AChE activity of rats in middle and high 1-BP groups was significantly higher than that of control and low 1-BP group (P < 0.05 or P < 0.01). The AChE activity in rat hippocampus of high 1-BP group obviously increased, as compared with control group as compared with control group (P < 0.05). There was no significant difference of cortical ChAT activity between three 1-BP groups and control group (P > 0.05). In the hippocampus, there was no difference of ChAT activity among the groups (P > 0.05).</p><p><b>CONCLUSION</b>1-BP exposure could significantly influence the learning-memory function in rats due to the increase of AChE activity.</p>

Effects of 1-bromopropane on neurological and hematological changes of female exposed workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the health effects of 1-bromopropane (1-BP) on female exposed workers.</p><p><b>METHODS</b>Four 1-BP manufacturing plants were investigated. Workers were interviewed with questionnaire and examined with neurobehavioral core test battery, nerve conduction velocity tests of nervus tibialis and nervus suralis, vibration sensation test, hematological and biochemical tests. Ambient 1-BP concentration was measured with detection tube, and time-weighed average levels of individual workers were estimated with passive samplers.</p><p><b>RESULTS</b>1-BP concentration in the plants ranged from 0 to 402.40 mg/m3 (Geomean 32.19 mg/m3). Time-weighted average exposure levels (TWA-8 h) ranged from 0.35 to 535.19 mg/m3 (Geomean 14.08 mg/m3). Compared with the control group, 1-BP exposed workers showed reduced motor nerve conduction velocity [(44.8 +/- 8.7) m/s] and sensory nerve conduction velocity [(45.5 +/- 4.9) m/s], prolonged distal latency [(7.5 +/- 2.1) ms], reduced toe vibration perception, and altered neurobehavior parameters(POMS vigor, tension, anxiety, confusion) significantly (P < 0.05). As to hematological and biochemical indicators, the exposed workers showed decreased white blood cell count [(5.6 +/- 2.17) x 10(3)/microl], red blood cell count [(3.9 +/- 0.4) x 10(6)/microl], hemoglobin [(121.1 +/- 14.5) g/L] and creatine kinase [(82.0 +/- 27.5) IU/L] (P < 0.05), and increased serum total protein (8.0 +/- 0.5 g/dl), lactate dehydrogenase [(335.2 +/- 356.6) IU/L], thyroid-stimulating hormone [(3.6 +/- 2.3) microIU/ml] and follicle-stimulating hormone levels (18.7 +/- 24.4 mIU/ml) (P < 0.05).</p><p><b>CONCLUSION</b>1-BP exposure may affect peripheral nerves and central nervous system, and lead to abnormal hematological and biomedical indicators.</p>

Exposure to 1-bromopropane causes dose-dependent neurological abnormalities in workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the dose-effect relationship between 1-bromopropane (1-BP) exposure and health effects in workers.</p><p><b>METHODS</b>Occupational field investigations were conducted in 1-BP factories. Ambient 1-BP concentrations were detected with detection tube, and the 8 h time-weighted average individual exposure levels (TWA-8 h) were measured by passive sampler. Workers underwent questionnaire survey, neurological examination, nerve conduction velocity examination, vibration sensation test. routine blood test as well as blood biochemical test. According to TWA values or TWA x duration values, workers were divided into three dose groups for dose-effect relationship analysis. USEPA BMDS 2.1 software was applied to calculate 1-BP benchmark dose (BMD) and its 95% lower limit (BMDL).</p><p><b>RESULTS</b>The TWA-8h concentrations ranged from 0.35 to 535.19 mg/m3 (geo-mean 14.08 mg/m3). Dose-dependent analysis showed that the motor nerve distal latency (linear regression coefficient was 0.066 6), vibration sensation of toes (linear regression coefficient were 0.157 2 and 0.193 9), creatine kinase (linear regression coefficient was -1.05) and thyroid stimulating hormone levels (linear regression coefficient was 0.1024) of 1-BP exposed workers changed in a dose-dependent manner (P < 0.05). BMD calculation based on DL as 1-BP toxic effect endpoint showed that TWA-8h of the BMD values and BMDL values were 50.55 mg/m3 and 30.78 mg/m3, respectively.</p><p><b>CONCLUSION</b>1-BP causes dose-dependent changes in tibial nerve DL, vibration sensation, CK and TSH levels.</p>

Occupational Reproductive Function Abnormalities and Bladder Cancer in Korea

The purpose of this study was to review occupational reproductive abnormalities and occupational bladder cancer in Korea and to discuss their toxicological implications. Reproductive dysfunction as a result of 2-bromopropane poisoning was first reported in Korean workers. In 1995, 23 of the 33 workers (25 female and 8 male workers) who were exposed to 2-bromopropane during the assembly of tactile switch parts developed reproductive and/or hematopoietic disorders. A total of 17 (68%) workers were diagnosed with ovarian failure. Two of the eight male workers experienced azoospermia and four workers experienced some degree of oligospermia or reduced sperm motility. In summary, 2-bromopropane poisoning caused severe reproductive effects in Korean workers. The prognosis was poor for reproductive dysfunction. A few cases of occupational bladder cancer have been reported in Korea, whereas other cancers of the urinary tract have not been reported after occupational exposure. A few cases of benzidine-induced cancer have been reported in Korea and 592 workers in Japan have received compensation for benzidine and beta-naphthylamine-induced cancer. In conclusion, a few cases of benzidine-induced occupational bladder cancer have been reported in Korea. However, benzidine-induced bladder cancer will likely be an important occupational health issue in Korea in the coming years.

Environmental evaluation of hot water treatments to control Liriomyza huidobrensis infesting plant material in transit

Though quarantine disinfestation treatments have been exempt from the methyl bromide phase out, it is still required to research and develop alternative treatments for fumigation of plant material in transit. This study investigated the ability of both the egg and pupal stages of the quarantine pest, South Americian leafminer, Liriomyza huidobrensis to survive submersion in water heated to temperatures between 40 and 50°C for varying periods of time. Large reductions in egg viability were recorded. However, the treatments also resulted in unacceptable levels of damage to the host plant material. Damage was uneconomically viable. Pupae were all killed exposure to water at 44°C for 20 min. Incubation of insect and plant material at either 5 or 20°C for 24 h before submersion in the hot water did not significantly alter the pests' ability to survive the treatments. The potential of hot water treatments to act as an alternative to methyl bromide fumigation for disinfecting plants in transit is discussed

Health profiles of methyl bromide applicators in greenhouses in Turkey

<p><b>INTRODUCTION</b>Methyl bromide is a toxic substance that has hazardous effects on human health with acute and chronic exposure. Our previous study showed that methyl bromide applicators frequently use large amounts of methyl bromide haphazardly in greenhouses in the prefectures of Narlidere and Balcova in the Aegean city of Izmir. This study aims to evaluate the health conditions of these workers.</p><p><b>MATERIALS AND METHODS</b>Our previous study showed that there are 38 methyl bromide applicators in our study area. After the informed consent of methyl bromide applicators was obtained, a questionnaire was used for a survey of demography and symptoms. Each subject was examined before and after application of the compound. Blood and urine samples were collected and stored. Blood samples were analysed for methyl bromide and bromide ion, kidney and liver function tests and lipid profile.</p><p><b>RESULTS</b>The age range of subjects was 19 to 53 years (mean age: 41 +/- 8.57). This study showed that methyl bromide applicators use large amounts of methyl bromide disregarding legal regulations and that some of them had nonspecific complaints. Subjects had been working as methyl bromide applicators for approximately 9.7 +/- 4.15 years. A total of 69.7% of methyl bromide applicators reported that they did not use protective equipment while 33.3% of them had a history of acute methyl bromide intoxication. A statistically significant relationship was found between the usage of protective equipment and the level of blood bromide ion in the blood (P <0.05).</p><p><b>CONCLUSION</b>Usage of methyl bromide, training, screening and follow-up of applicators must be rigorously controlled in accordance with national legal arrangements and international protocols. Greater efforts are required in the implementation of controls to achieve the targets set by the legal regulations and to ensure continual improvement in the limitation of the risks of this environmental hazard.</p>

Identification of a Taq DNA polymerase inhibitor from the red seaweed Symphyocladia latiuscula.

Two inhibitors of Taq DNA polymerase were isolated from the marine red alga Symphyocladia latiuscula. The inhibitors were purified by methanol extraction, molecular fractionation below 3000 MW and reverse-phase HPLC. The purified compound SL-1 containing three bromines was identified as 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol (C7H5Br3O3: MW374) by NMR and MS analyses. The purified compound SL-2 was identified as 2,3, 6-tribromo-4,5-dihydroxybenzyl methyl ether(C8H7Br3O3: MW388). In a 25-microl reaction mixture containing 1.5 units of Taq DNA polymerase, the enzyme was completely inhibited by 0.5 microg SL-1 or 5 microg SL-2.

Neurological manifestation of methyl bromide intoxication.

Methyl bromide is a highly toxic gas with poor olfactory warning properties. It is widely used as insecticidal fumigant for dry foodstuffs and can be toxic to central and peripheral nervous systems. Most neurological manifestations of methyl bromide intoxication occur from inhalation. Acute toxicity characterized by headache, dizziness, abdominal pain, nausea, vomiting and visual disturbances. Tremor, convulsion, unconsciousness and permanent brain damage may occur in severe poisoning. Chronic exposure can cause neuropathy, pyramidal and cerebellar dysfunction, as well as neuropsychiatric disturbances. The first case of methyl bromide intoxication in Thailand has been described. The patient was a 24-year-old man who worked in a warehouse of imported vegetables fumigated with methyl bromide. He presented with unstable gait, vertigo and paresthesia of both feet, for two weeks. He had a history of chronic exposure to methyl bromide for three years. His fourteen co-workers also developed the same symptoms but less in severity. Neurological examination revealed ataxic gait, decreased pain and vibratory sense on both feet, impaired cerebellar signs and hyperactive reflex in all extremities. The serum concentration of methyl bromide was 8.18 mg/dl. Electrophysilogical study was normal. Magnetic resonance imaging of the brain (MRI) revealed bilateral symmetrical lesion of abnormal hypersignal intensity on T2 and fluid-attenuation inversion recovery (FLAIR) sequences at bilateral dentate nuclei of cerebellum and periventricular area of the fourth ventricle. This incident stresses the need for improvement of worker education and safety precautions during all stages of methyl bromide fumigation.

Two Cases of Methyl Bromide Intoxication Mimicking Bickerstaff's Brainstem Encephalitis

BACKGROUND: Methyl bromide is toxic to the central and peripheral nervous systems. Two patients with occupational exposure to this agent are described. CASE: Two cases of previously healthy young men were involved. They had worked in a fumigating plant spraying fruits using methyl bromide for several months before admission. They showed general weakness, severe ataxia, bilateral dysmetria and bilateral lateral gaze limitation. And gaze-evoked nystagmus was observed in one of them. Brain MRI showed symmetrically increased signal intensity lesions including the brainstem, cerebellum and splenium of corpus callosum. After conservative treatment, they gradually improved over the next few weeks. CONCLUSIONS: Symmetry and topography of our patients??clinical and radiographic abnormalities support the proposal that methyl bromide exposure can produce symptoms similar to Bickerstaff's brainstem encephalitis.

Estudio preliminar sobre los niveles de exposición a PBDES en sangre y leche materna en México / Exposure levels of PBDES in blood and breast milk in Mexico, a preliminary study

Los retardantes de flama bromados han sido muy usados en las últimas décadas en muchos productos de consumo. Su producción, uso, lipofilicidad y persistencia, los han vuelto contaminantes ambientales ubicuos. Han sido detectados en el ser humano en varios países y poco se conoce sobre susefectos tóxicos. El propósito de este estudio fue determinar de manera preliminar los niveles de exposición a difeniléteres polibromados (PBDEs) en la población mexicana. Se tomaron muestras de sangre a 5 mujeres de una zona urbana y muestras de leche materna a 7 de una zona rural. Los niveles de PBDEs en las mujeres de la zona urbana fueron de 21.5-37.5 ng/glípido y los de las mujeres rurales fueron 0.8-5.4 ng/g lípido.

The brominated flame retardants have been used in the last decades inmany products. Their production, use, lipofilicity and persistence, make them ubiquituos in the environment. They have been detected in humans in several countries and little is known about their toxics effects. The aim of this pilot study was to determine exposure levels of polybrominated diphenylethers (PBDEs) in the Mexican population, blood samples were taken from five women living in an urban area, whereas breast milk samples were collected from seven rural women. The levels of PBDEs in theurban area were 21.5-37.5 ng/g lipid; whereas milk concentrations in rural women were 0.8-5.4 ng/glipid.

Biocontrol of root and crown rot in tomatoes under greenhouse conditions using Trichoderma harzianum and Paenibacillus lentimorbus: additional effect of solarization

Trichoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (Pl629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici - Pyrenochaeta lycopersici - Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from 88.7 percent to 21.2 percent and from 78.4 percent to 35.7 percent in the summer and in the winter assay, respectively. None of the bio-controllers could replace MeBr in the winter assay, but Th650 and Pl629 reduced root damage caused by this complex in the summer assay. Treatments with bio-controllers were improved by their combination with solarization in this season. Independent evaluations showed that the positive control of Th650 towards R. solani and the lack of effect on P. lycopersici correlates well with the endochitinase pattern expressed by Th650 in response to these phytopathogens. Root damage caused by R. solani can be controlled at a similar level as it does MeBr in summer assays, thus representing an alternative to the use of this chemical fungicide for the control of this phytopathogen.

Effects of Benzoapyrene, 2-Bromopropane, Phenol and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin on Proinflammatory Cytokines Gene Expression by Mice Spleen Cells

The detrimental effects of environmental pollutants on the health of the individual are generally accepted, although the mechanisms of these effects remain to be incompletely understood. In the present study, we examined the effects of B[a]P, 2-BP, phenol and TCDD on proinflammatory cytokine gene expression in mice spleen cells which were stimulated with anti-CD3. 10-9M TCDD increased IFN gammar and TNF alpha gene expression, but suppressed IL-1 gene expression. 10-6M phenol inhibited IL-1, IL-6 and TNF alpha gene expression, and 10-6M of 2-BP downregulated TNF alpha gene expression. However, 10-6M of B[a]P did not influence on IL-1, IL-6, IFN gammar and TNF alpha gene expression. These findings suggest that TCDD may impair the immune functions of mice by enhancing proinflammatory cytokines production, whereas phenol and 2-BP may impair the functions by inhibiting the production of these cytokines.