Irreversible color vision losses in patients with chronic mercury vapor intoxication

This longitudinal study addresses the reversibility of color vision losses in subjects who had been occupationally exposed to mercury vapor. Color discrimination was assessed in 20 Hg-exposed patients (mean age = 42.4 +/- 6.5 years; 6 females and 14 males) with exposure to Hg vapor during 10.5 +/- 5.3 years and away from the work place (relative to 2002) for 6.8 +/- 4.2 years. During the Hg exposure or up to one year after ceasing it, mean urinary Hg concentration was 47 +/- 35.4 mu g/g creatinine. There was no information on Hg urinary concentration at the time of the first tests, in 2002 (Ventura et al., 2005), but at the time of the follow-up tests, in 2005, this value was 1.4 +/- 1.4 mu g/g creatinine for patients compared with 0.5 +/- 0.5 mu g/g creatinine for controls (different group from the one in Ventura et al. (2005)). Color vision was monocularly assessed using the Cambridge Colour Test (CCT). Hg-exposed patients had significantly worse color discrimination (p < 0.02) than controls, as evaluated by the size of MacAdam`s color discrimination ellipses and color discrimination thresholds along protan, deutan, and tritan confusion axes. There were no significant differences between the results of the study in Ventura et al. (2005) and in the present follow-up measurements, in 2005, except for worsening of the tritan thresholds in the best eye in 2005. Both chromatic systems, blue-yellow and red-green, were affected in the first evaluation (Ventura et al., 2005) and remained impaired in the follow-up testing, in 2005. These findings indicate that following a long-term occupational exposure to Hg vapor, even several years away from the source of intoxication, color vision impairment remains irreversible.

Electrophysiological evidence for impairment of contrast sensitivity in mercury vapor occupational intoxication

Contrast sensitivity (CS) was evaluated in 41 former workers from a lamp manufacturing plant who were on disability retirement due to exposure to mercury and 14 age-matched controls. The CS was measured monocularly using the sweep visual evoked potential (sVEP) paradigm at 6 spatial frequencies (0.2, 0.8, 2.0, 4.0, 15.0, and 30 cpd). Statistical difference (p < 0.05) was found between the controls and the patient right and left eyes for 2.0 and 4.0 cpd. According the results in those spatial frequencies the eyes were classified in best and worst. Statistical differences were found between the controls and the best eyes for 2.0 and 4.0 cpd and for 0.8, 2.0, and 4.0 cpd for their worst eyes. No correlation was found between CS results and the time of exposure (mean 8.9 yr +/- 4.1), time away from the mercury source (mean = 6.0 yr +/- 3.9), urinary mercury level at the time of work (mean = 40.6 mu g/g +/-36.3) or with the mercury level at the CS measurement time (mean = 1.6 mu g/g +/-1.1). We show the first evidence of a permanent impairment in CS measured objectively with the sVEP. Our data complement the previous psychophysical works reporting a diffuse impairment in the CS function showing a CS reduction in the low to middle spatial frequencies. In conclusion, non-reversible CS impairment was found in occupational exposure to mercury vapor. We suggest that CS measurement should be included in studies of the mercury effects of occupational exposure. (C) 2007 Elsevier Inc. All rights reserved.

Cardiac Rhythm Disturbances Associated with Amlodipine Acute Intoxication

Amlodipine is a dihydropyridine calcium channel antagonist extensively used for the treatment of arterial hypertension, with predominant effect on the peripheral vascular territory. In most cases of severe intoxication, important hypotension and reflex tachycardia are usually observed. We report a case of young man with severe amlodipine intoxication that developed important bradyarrhythmias, such as low atrial rhythm, prolonged PR interval, atrioventricular block, and left bundle branch block. These rhythm disturbances suggest that, during acute intoxication, dihydropyridine loses its selective action on the vascular territory and can depress automatism and conduction of cardiac electrical stimulus.

Preliminary Findings on the Effects of Occupational Exposure to Mercury Vapor Below Safety Levels on Visual and Neuropsychological Functions

Objective: To evaluate whether there are visual and neurophysical decrements in workers with low exposure to Hg vapor. Methods: Visual fields, contrast sensitivity, color vision, and neuropsychological functions were measured in 10 workers (32.5 +/- 8.5 years) chronically exposed to Hg vapor (4.3 +/- 2.8 years; urinary Hg concentration 22.3 +/- 9.3 mu g/g creatinine). Results: For the worst eyes, we found altered visual field thresholds, lower contrast sensitivity, and color discrimination compared with controls (P < 0.05). There were no significant differences between Hg-exposed subjects and controls on. neuropsychological tests. Nevertheless, duration of exposure was statistically correlated to verbal memory and depression scores. Conclusions: Chronic exposure to Hg vapor at currently accepted safety levels was found to be associated with visual losses but not with neuropsychological dysfunctions in the sample of workers studied. (J Occup Environ Med. 2009,51:1403-1412)

Visual field losses in workers exposed to mercury vapor

Visual field losses associated with mercury (Hg) exposure have only been assessed in patients exposed to methylmercury. Here we evaluate the automated visual field in 35 ex-workers (30 males; 44.20+/-5.92 years) occupationaly exposed to mercury vapor and 34 controls (21 males; 43.29+/-8.33 years). Visual fields were analyzed with the Humphrey Field Analyzer II (model 750i) using two tests: the standard automated perimetry (SAP, white-on-white) and the short wavelength automated perimetry (SWAP, blue-on-yellow) at 76 locations within a 27 degrees central visual field. Results were analyzed as the mean of the sensitivities measured at the fovea, and at five successive concentric rings, of increasing eccentricity, within the central field. Compared to controls, visual field sensitivities of the experimental group measured using SAP were lower for the fovea as well as for all five eccentricity rings (p<0.05). Sensitivities were significantly lower in the SWAP test (p<0.05) for four of the five extra-foveal eccentricity rings; they were not significant for the fovea (p = 0.584) or for the 15 degrees eccentricity ring (p = 0.965). These results suggest a widespread reduction of sensitivity in both visual field tests. Previous reports in the literature describe moderate to severe concentric constriction of the visual field in subjects with methylmercury intoxication measured manually with the Goldman perimeter. The present results amplify concerns regarding potential medical risks of exposure to environmental mercury sources by demonstrating significant and widespread reductions of visual sensitivity using the more reliable automated perimetry. (C) 2007 Elsevier Inc. All rights reserved.

THE NEGATIVE EFFECTS OF ALCOHOL HANGOVER ON HIGH-ANXIETY PHENOTYPE RATS ARE INFLUENCED BY THE GLUTAMATE RECEPTORS OF THE DORSAL MIDBRAIN

Alcoholism is a chronic disorder characterized by the appearance of a withdrawal syndrome following the abrupt cessation of alcohol intake that includes symptoms of physical and emotional disturbances, anxiety being the most prevalent symptom. In humans, it was shown that anxiety may increase the probability of relapse. In laboratory animals, however, the use of anxiety to predict alcohol preference has remained difficult. Excitatory amino acids as glutamate have been implicated in alcohol hangover and may be responsible for the seizures and anxiety observed during withdrawal. The dorsal periaqueductal gray (DPAG) is a midbrain region critical for the modulation/expression of anxiety- and fear-related behaviors and the propagation of seizures induced by alcohol withdrawal, the glutamate neurotransmission being one of the most affected. The present study was designed to evaluate whether low- (LA) and high-anxiety rats (HA), tested during the alcohol hangover phase, in which anxiety is the most prevalent symptom, are more sensitive to the reinforcing effects of alcohol when tested in a voluntary alcohol drinking procedure. Additionally, we were interested in investigating the main effects of reducing the excitatory tonus of the dorsal midbrain, after the blockade of the ionotropic glutamate receptors into the DPAG, on the voluntary alcohol intake of HA and LA motivated rats that were made previously experienced with the free operant response of alcohol drinking. For this purpose, we used local infusions of the N-metil D-Aspartato (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-kainate receptors antagonist DL-2-Amino-7-phosphonoheptanoic acid - DL-AP7 (10 nmol/0.2 mu l) and L-glutamic acid diethyl ester - GDEE (160 nmol/0.2 mu l) respectively. Alcohol intoxication was produced by 10 daily bolus intraperitonial (IP) injections of alcohol (2.0 g/kg). Peak-blood alcohol levels were determined by gas-chromatography analysis in order to assess blood-alcohol content. Unconditioned and conditioned anxiety-like behavior was assessed by the use of the fear-potentiated startle procedure (FPS). Data collected showed that anxiety and alcohol drinking in HA animals are positively correlated in animals that were made previously familiarized with the anxiolytic effects of alcohol. In addition, anxiety-like behavior induced during alcohol hangover seems to be an effect of changes in glutamatergic neurotransmission into DPAG possibly involving AMPA/kainate and NMDA receptors, among others. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Phoneutria nigriventer spider toxin Tx2-6 causes priapism and death: A histopathological investigation in mice

Phoneutria nigriventer spider bite causes priapism, an effect attributed to the peptide toxins Tx2-5 and Tx2-6 and involving nitric oxide. Tx2-6 (MW = 5287) is known to delay the inactivation of Sodium channels in the same fashion as many other venom toxins. In the present study we evaluated the i.p. dose that induces priapism and the other symptoms in mice. Animals killed by the toxin or crude venom (0.85 mg/kg) were autopsied and a pathological study of brain, lung, kidney, liver and heart was undertaken using standard techniques. The same protocol was employed with animals injected with crude venom. Results showed that priapism is the first sign of intoxication, followed by piloerection, abundant salivation and tremors. An i.p. injection of about 0.3 mu g/kg induced only priapism with minimal side-effects. The most remarkable histological finding was a general vascular congestion in all organs studied. Penis showed no necrosis or damage. Lungs showed vascular congestion and alveolar hemorrhage. Heart showed also sub-endothelial hemorrhage. Brain showed only a mild edema and vascular congestion. Results obtained with crude venom closely resemble those of purified toxin. We conclude that Tx2-6 have profound effects on the vascular bed especially in lungs and heart, which may be the cause of death. Interestingly brain tissue was less affected and the observed edema may be attributed to respiratory impairment. To the best of our knowledge this is the first histopathological investigation on this toxin and venom suggesting a possible cause of death. (C) 2012 Elsevier Ltd. All rights reserved.

The EXTRIP (EXtracorporeal TReatments In Poisoning) workgroup: Guideline methodology

Extracorporeal treatments (ECTRs), such as hemodialysis and hemoperfusion, are used in poisoning despite a lack of controlled human trials demonstrating efficacy. To provide uniform recommendations, the EXTRIP group was formed as an international collaboration among recognized experts from nephrology, clinical toxicology, critical care, or pharmacology and supported by over 30 professional societies. For every poison, the clinical benefit of ECTR is weighed against associated complications, alternative therapies, and costs. Rigorous methodology, using the AGREE instrument, was developed and ratified. Methods rely on evidence appraisal and, in the absence of robust studies, on a thorough and transparent process of consensus statements. Twenty-four poisons were chosen according to their frequency, available evidence, and relevance. A systematic literature search was performed in order to retrieve all original publications regardless of language. Data were extracted on a standardized instrument. Quality of the evidence was assessed by GRADE as: High = A, Moderate = B, Low = C, Very Low = D. For every poison, dialyzability was assessed and clinical effect of ECTR summarized. All pertinent documents were submitted to the workgroup with a list of statements for vote (general statement, indications, timing, ECTR choice). A modified Delphi method with two voting rounds was used, between which deliberation was required. Each statement was voted on a Likert scale (1-9) to establish the strength of recommendation. This approach will permit the production of the first important practice guidelines on this topic.

Measurement of airborne gunshot particles in a ballistics laboratory by sector field inductively coupled plasma mass spectrometry

The present study aimed determines lead (Pb), antimony (Sb) and barium (Ba) as the major elements present in GSR in the environmental air of the Ballistics Laboratory of the Sao Paulo Criminalistics Institute (I.C.-S.P.), Sao Paulo, SP, Brazil. Micro environmental monitors (mini samplers) were located at selected places. The PM2.5 fraction of this airborne was collected in, previously weighted filters, and analyzed by sector field inductively coupled plasma mass spectrometer (SF-HR-ICP-MS). The higher values of the airborne lead, antimony and barium, were found at the firing range (lead (Pb): 58.9 mu g/m(3); barium (Ba): 6.9 mu g/m(3); antimony (Sb): 7.3 mu g/m(3)). The mean value of the airborne in this room during 6 monitored days was Pb: 23.1 mu g/m(3); Ba: 2.2 mu g/m(3); Sb: 1.5 mu g/m(3). In the water tank room, the air did not show levels above the limits of concern. In general the airborne lead changed from day to day, but the barium and antimony remained constant. Despite of that, the obtained values suggest that the workers may be exposed to airborne lead concentration that can result in an unhealthy environment and could increase the risk of chronic intoxication. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

The Use of Ultrasonography to Study Teratogenicity in Ruminants: Evaluation of Ipomoea carnea in Goats

Background: Ipomoea carnea (I. carnea) is a poisonous plant found in Brazil and other tropical countries that often poison livestock. The plant contains the alkaloids calystegines and mainly swainsonine, which inhibit cellular enzymes and cause systematic cell death. The objective of this study was to evaluate the perinatal effects of I. carnea in goats. Methods: Forty-seven pregnant goats were randomly allocated into 5 treatment groups and given the following doses (g/kg BW) of I. carnea: 0 (IC0), 1.0 (IC1), 3.0 (IC3), 5.0 (IC5) and 7.5 (IC7). The treatment animals were given fresh I. carnea from day 27 of gestation to parturition. Weight gains and serum biochemistry were evaluated. Fetuses were evaluated using ultrasonographic measurements. Results: Goats from the IC7 group showed clinical signs of poisoning. Ultrasound examination revealed that I. carnea feeding in all treatment groups reduced fetal movement compared to the controls. There was an increase in the total number of birth defects (retrognathia and arthrogyposis) in the IC7 and IC5 groups compared to the controls. Conclusion: The results show that I. carnea has teratogenic potential in goats. In addition, ultrasounds were useful in evaluating fetotoxicity and teratogenicity. Birth Defects Res (Part B) 00:17, 2012. (c) 2012 Wiley Periodicals, Inc.

Pharmacological interventions in the treatment of the acute effects of cannabis: a systematic review of literature

Abstract Background Cannabis intoxication is related to a number of physical and mental health risks with ensuing social costs. However, little attention has been given to the investigation of possible pharmacological interactions in this condition. Objective To review the available scientific literature concerning pharmacological interventions for the treatment of the acute effects of cannabis. Methods A search was performed on the Pubmed, Lilacs, and Scielo online databases by combining the terms cannabis, intoxication, psychosis, anxiety, and treatment. The articles selected from this search had their reference lists checked for additional publications related to the topic of the review. Results The reviewed articles consisted of case reports and controlled clinical trials and are presented according to interventions targeting the physiological, psychiatric, and cognitive symptoms provoked by cannabis. The pharmacological interventions reported in these studies include: beta-blockers, antiarrhythmic agents, antagonists of CB-1 and GABA-benzodiazepine receptors, antipsychotics, and cannabidiol. Conclusion Although scarce, the evidence on pharmacological interventions for the management of cannabis intoxication suggests that propanolol and rimonabant are the most effective compounds currently available to treat the physiological and subjective effects of the drug. Further studies are necessary to establish the real effectiveness of these two medications, as well as the effectiveness of other candidate compounds to counteract the effects of cannabis intoxication, such as cannabidiol and flumazenil.

Body packing by rectal insertion of cocaine packets: a case report

Background: Body packing is used for international drug transport, immediate drug concealment during a police searching or introducing drugs inside prisons. Despite the high level of specialization of dealers who have started to manufacture more complex packs, up to 5% of patients could develop intoxication due to pack rupture. Bowel obstruction is another acute complication. Case presentation: A 27-year-old black male patient was sent to the hospital by court order for clinical evaluation and toxicological examination. The patient was conscious, oriented, had good color, normal arterial pressure and heart rate, and no signs of acute intoxication. Abdominal examination revealed discrete pain upon deep palpation and a small mass in the left iliac fossa. A plain abdominal radiograph revealed several oval structures located in the rectum and sigmoid. Fasting and a 50 g dose of activated charcoal every six hours were prescribed. After three days, the patient spontaneously evacuated 28 cocaine packs. Conclusion: Adequate clinical management and prompt identification of potential complications are of fundamental importance in dealing with body packing.

Using selected scenes from Brazilian films to teach about substance use disorders, within medical education

CONTEXT AND OBJECTIVES: Themes like alcohol and drug abuse, relationship difficulties, psychoses, autism and personality dissociation disorders have been widely used in films. Psychiatry and psychiatric conditions in various cultural settings are increasingly taught using films. Many articles on cinema and psychiatry have been published but none have presented any methodology on how to select material. Here, the authors look at the portrayal of abusive use of alcohol and drugs during the Brazilian cinema revival period (1994 to 2008). DESIGN AND SETTING: Qualitative study at two universities in the state of São Paulo. METHODS: Scenes were selected from films available at rental stores and were analyzed using a specifically designed protocol. We assessed how realistic these scenes were and their applicability for teaching. One author selected 70 scenes from 50 films (graded for realism and teaching applicability > 8). These were then rated by another two judges. Rating differences among the three judges were assessed using nonparametric tests (P < 0.001). Scenes with high scores (> 8) were defined as "quality scenes". RESULTS: Thirty-nine scenes from 27 films were identified as "quality scenes". Alcohol, cannabis, cocaine, hallucinogens and inhalants were included in these. Signs and symptoms of intoxication, abusive/harmful use and dependence were shown. CONCLUSIONS: We have produced rich teaching material for discussing psychopathology relating to alcohol and drug use that can be used both at undergraduate and at postgraduate level. Moreover, it could be seen that certain drug use behavioral patterns are deeply rooted in some Brazilian films and groups.

Hypervitaminosis A-induced hepatic fibrosis in a cat

Rationale: The excessive intake of vitamin A in the form of vitamin concentrate, supplement or vitamin-rich liver can result in hypervitaminosis A in man and animals. Although osteopathologies resulting from chronic vitamin A intoxication in cats are well characterized, no information is available concerning feline hypervitaminosis A-induced liver disease. Clinical summary: We report the first case of hepatic stellate cell lipidosis and hepatic fibrosis in a domestic cat that had been fed a diet based on raw beef liver. Radiographic examination revealed exostoses and ankylosis between vertebrae C1 and T7, compatible with deforming cervical spondylosis. Necropsy showed a slightly enlarged and light yellow to bronze liver. Microscopic and ultrastructural analyses of liver tissues revealed diffuse and severe liver fibrosis associated with hepatic stellate cell hyperplasia and hypertrophy. These cells showed immunopositive staining for α-smooth muscle actin and desmin markers. The necropsy findings of chronic liver disease coupled with osteopathology supported the diagnosis of hypervitaminosis A. Practical relevance: As in human hepatology, if there is dietary evidence to support increased intake of vitamin A, then hypervitaminosis A should be considered in the differential diagnosis of chronic liver disease in cats.