The effects of hexachloronaphthalene on selected parameters of heme biosynthesis and systemic toxicity in female wistar rats after 90-day oral exposure.

Hexachloronaphthalenes (HxCNs) are the most toxic congeners of polychlorinated naphthalenes, a group of compounds lately included into the list of persistent organic pollutants (POPs). This study presents the effects of 90-day intragastric administration of HxCN to female Wistar rats at doses of 0.03, 0.1, and 0.3 mg/kg body weight. The study examined selected parameters of the heme synthesis pathway, oxidative stress, hepatic cytochromes level, and basic hematology indicators. A micronucleus test was also performed. The subchronic exposure of rats to HxCN resulted in disruption of heme biosynthesis, hematological disturbances, and hepatotoxicity. The highest dose of HxCN inhibited aminolevulinic acid dehydratase (ALA-D) and uroporphyrinogen decarboxylase (URO-D). Accumulation of higher carboxylated porphyrins in the liver and increased excretion of 5-aminolevulinic acid in the urine was observed after a dose of 0.1 mg/kg body weight. The most sensitive effect of HxCN in rats was very strong induction of hepatic CYP1A1 activity, which was observed after the lowest dose. The highest dose of HxCN induced significant thrombocytopenia, thymic atrophy and hepatotoxicity, expressed as hepatomegaly and hepatic steatosis.

[Narcolepsy: etiology, clinical features, diagnosis and treatment]. / Narkolepsja: etiologia, obraz kliniczny, diagnostyka i leczenie.

 Narcolepsy is a chronic hypersomnia characterized by excessive daytime sleepiness (EDS) and manifestations of disrupted rapid eye movement sleep stage (cataplexy, sleep paralysis, and hypnagogic/hypnopompic hallucinations). Mechanisms underlying narcolepsy are not fully understood. Experimental data indicate that the disease is caused by a loss of hypocretin neurons in the hypothalamus, likely due to an autoimmune process triggered by environmental factors in susceptible individuals. Most patients with narcolepsy and cataplexy have very low hypocretin-1 levels in the cerebrospinal fluid. An appropriate clinical history, polysomnogram, and multiple sleep latency test are necessary for diagnosis of the disease. Additionally, two biological markers, i.e., cerebrospinal fluid hypocretin-1 levels and expression of the DQB1*0602 gene, are used. The treatment of narcolepsy is aimed at the different symptoms that the patient manifests. Excessive daytime sleepiness is treated with psychostimulants (amphetamine-like, modafinil and armodafinil). Cataplexy is treated with sodium oxybate (GHB), tricyclic antidepressants, or selective serotonin and noradrenaline reuptake inhibitors. Sleep paralysis, hallucinations, and fragmented sleep may be treated with sodium oxybate. Patients with narcolepsy should follow proper sleep hygiene and avoid strong emotions.