Effects of thallium poisoning on intellectual function

D-Penicillamine Reveals the Amelioration of Seizure-Induced Neuronal Injury via Inhibiting Aqp11-Dependent Ferroptosis

Repetitive seizures, a common phenomenon in diverse neurologic conditions such as epilepsy, can undoubtedly cause neuronal injury and our prior work reveals that ferroptosis is a contributing factor of neuronal damage post seizure. However, there is no drug available in clinical practice for ameliorating seizure-induced neuronal impairment via targeting ferroptosis. Our present work aimed to explore whether D-penicillamine (DPA), an originally approved drug for treating Wilson’s disease, inhibited neuronal ferroptosis and alleviated seizure-associated brain damage. Our findings revealed that DPA remarkably improved neuronal survival in kainic acid (KA)-treated mouse model. Furthermore, ferroptosis-associated indices including acyl-coA synthetase long chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (Ptgs2) gene and lipid peroxide (LPO) level were significantly decreased in KA mouse model after DPA treatment. In a ferroptotic cell death model induced by glutamate or erastin, DPA was also validated to evidently suppress neuronal ferroptosis. The results from RNA-seq analysis indicated that Aqp11, a gene coding previously reported channel protein responsible for transporting water and small solutes, was identified as a molecular target by which DPA exerted anti-ferroptotic potential in neurons. The experimental results from in vivo Aqp11 siRNA transfer into the brain also confirmed that knockdown of Aqp11 abrogated the inhibitory effect of seizure-induced ferroptosis after DPA treatment, suggesting that the effects of DPA on ferroptosis process are dependent upon Aqp11. In conclusion, DPA can be repurposed to cure seizure disorders such as epilepsy.

Determination of thallium in urine, blood, and hair in illicit opioid users in Iran

CONTEXT

Heavy metals, including thallium and lead, are introduced to illicit drug users' body as a result of using drugs such as cocaine and heroin.

OBJECTIVE

This study aimed to determine urine, blood, and hair thallium (Tl) concentrations in illicit opioid users along with the relevant clinical signs and symptoms consistent with thallotoxicosis and to compare them with the corresponding variables in the control non-opioid user group.

MATERIALS AND METHODS

This case-control study was conducted on 50 illicit opioid users who had abused opioids continuously for more than a year, referred to Amirie Drug Abuse Treatment Clinic in Kashan, Iran. The control group included 50 non-opioid users. Thallium concentrations in urine, blood, and hair were assessed in both groups (n = 100) using electrothermal (graphite furnace) atomic absorption spectrometry (ET AAS, GF AAS).

RESULTS

In the studied group, the median (interquartile range) concentrations of thallium in urine, blood, and hair were 54.8 ± 79.9 μg/L, 14.5 ± 11.1 μg/L, and 5.4 ± 3.7 µg/g, respectively; these values were 4.8 ± 5.2 μg/L, 2.5 ± 2.4 μg/L, and 1.4 ± 1.1 µg/g, respectively, in the control group. There were significant differences in urine, blood, and hair thallium concentrations between the study group and the control group (p < 0.001). There were significant correlations between duration of illicit opioid use and urine thallium concentrations (r = 0.394, p = 0.005) and hair thallium concentrations (r = 0.293, p = 0.039), but not with blood thallium concentrations (r = 0.246, p = 0.085). Urine and blood thallium concentrations of illicit opioid users with clinical signs and symptoms consistent with thallotoxicosis of weakness (p = 0.01), depression (p = 0.03), and headache (p = 0.03) were higher than users without these problems.

DISCUSSION AND CONCLUSION

The results of the study showed that thallium concentrations in urine, blood, and hair in illicit opioid users were significantly higher than the comparable concentrations in the control group. This can be due to the use of illicit opioids adulterated with thallium. Also, this study showed long-term illicit opioid use may lead to thallium exposure. In addition, cigarette smoking was associated with increased thallium exposure.

Examining of Thallium in Cigarette Smokers

Smoking is one of the sources of thallium which is considered as a toxic heavy metal. The aim of this study was to determine urinary thallium levels and related variables in smokers, compared to a control group. The study was conducted on 56 participants who had smoked continuously during the year before they were referred to Kashan Smoking Cessation Clinic. Fifty-three nonsmokers who were family members or friends of the smokers were selected as the control group. Urinary thallium was measured in both groups (n = 109) using atomic absorption spectrophotometry. The mean value (with SD) for urinary thallium in the smokers (10.16 ± 1.82 μg/L) was significantly higher than in the control group (2.39 ± 0.63 μg/L). There was a significant relationship between smoking duration and urinary thallium levels (P = 0.003). In a subgroup of smokers who was addicted to opium and opium residues (n = 9), the mean level of thallium (37.5 ± 13.09 μg/L) was significantly higher than in the other smokers (4.93 ± 4.45; P = 0.001). Multiple regression analysis showed opioid abuse, insomnia, and chronic obstructive pulmonary disease (COPD), together were strong predictors of urinary thallium levels in smokers. There was no significant difference in thallium level in hookah smokers (P = 0.299) or in those with COPD compared to other smokers (P = 0.375). Urinary thallium levels of smokers with clinical signs of depression, sleep disorders, memory loss, and sweating were higher than those of smokers without these signs. Since thallium, as other toxic metals is accumulated in the body, and cigarette smoking also involves carcinogenic exposures and health hazards for passively exposed people, the need for cigarette control policies is emphasized.

A case of acute thallotoxicosis successfully treated with double-filtration plasmapheresis

The authors report a 48-year-old Chinese woman who presented with acute peripheral neuritis with progressive alopecia. Laboratory examinations disclosed a high blood concentration of thallium (97 microg/L) versus a normal value (0.9 microg/L), and she was diagnosed as having acute thallotoxicosis. After her hospitalization, the cutantest of dimercaptopropansulfonate sodium was positive and the patient refused to take Prussian blue because it caused constipation. She rapidly entered remission after assistance via double-filtration plasmapheresis (DFPP), suggesting the potential efficacy of DFPP for thallotoxicosis.

Toxic Encephalopathies

Effective brain function is dependent on precise and complex interactions among neurotransmitters, hormones, enzymes, and electrolytes. Many of the chemically complex substances with which we come into contact can disrupt this intricately balanced system. Toxic substances, whether ingested, inhaled, or absorbed through the skin, may cause an encephalopathic state directly by affecting the brain itself or indirectly by compromising the brain's supportive systems. The article focuses on neurotoxins (heavy metals, solvents and vapors, pesticides, and natural neurotoxins) that directly induce an encephalopathic state.

Combined D-penicillamine and prussian blue as antidotal treatment against thallotoxicosis in rats: evaluation of cerebellar lesions

Rats were treated with a single dose of thallium acetate (32 mg/kg i.p.) and the antidotal effect of D-penicillamine and prussian blue given alone or in combination was assessed by means of evaluation of the thallium-induced cerebellar histological lesions. After thallium poisoning (24 h), antidotes were administered for 4 days as follows: D-penicillamine (DP) 25 mg/kg, i.p. twice daily; prussian blue (PB), 50 mg/kg p.o., twice daily. Mortality among the treatment groups was as follows: control, 87.5%; DP, 100%; PB, 56.25%; DP+PB, 25%. Three days after these treatments, rats treated with the combination DP+PB presented a significantly lower number of altered Purkinje cells in cerebellum as compared with those of the thallium alone treated animals, indicating adequate protection by this antidote treatment against thallium neurotoxicity. Prussian blue protected against thallium-induced neurotoxicity to a lesser extent as compared with the effects obtained by the DP+PB protection. DP did not protect against thallium-induced alterations of Purkinje cells. These results confirm the efficacy of the combined antidotal treatment of DP and PB against thallium toxicity in rats, and support the possible application in human cases of thallotoxicosis.