[Hypothalamic hamartoma dissection using focused ultrasound under MRI control. The first successful experience in Russia]

Treatment of motor disorders by MRI-guided focused ultrasound is an alternative to neuro- and radiosurgery such as stereotactic radiofrequency ablation and thalamotomy with a gamma knife. However, safety, efficacy and feasibility of this technology for intracranial neoplasms are still unclear. The authors report successful hypothalamic hamartoma dissection by MRI-guided focused ultrasound in a 32-year-old woman with drug-resistant gelastic epilepsy and violent laughter and crying attacks. Magnetic resonance imaging revealed type II hypothalamic hamartoma. The last one was detached from surrounding brain tissue by MRI-guided focused ultrasound without side effects. Symptoms regressed immediately after surgery. No laughter and crying attacks were observed throughout 6-month follow-up.

[Primary vitrectomy in the treatment of retinopathy of prematurity with unfavorable progression]

PURPOSE

The study aims to determine the indications and evaluate the results of primary vitrectomy in unfavorable progression of stage III active retinopathy of prematurity (ROP).

MATERIAL AND METHODS

The control group consisted of 17 patients (28 eyes) with unfavorable progression of stage III ROP, who had the disease progress after coagulation of the avascular retina and underwent the second stage of treatment - vitrectomy. The main group consisted of 5 patients (10 eyes) with unfavorable progression of stage III ROP, who underwent primary vitrectomy. Gestational age at birth was 24-30 weeks, body weight ranged from 680 to 1250 g. According to spectral optical coherence tomography (SOCT) and OCT angiography (OCT-A), the initial state of the retina and vitreoretinal interface in patients of the main and control groups were identical.

RESULTS

A retrospective analysis of control patients, according to SOCT and OCT-A data, showed the spread of neovascularization beyond the retinal plane, its interaction with the posterior hyaloid membrane and vitreous body structures in the early stages of the disease, traction changes in the underlying retina, areas of retinoschisis, as well as thickening of the posterior hyaloid membrane. The tactics of treating patients with unfavorable progression of stage III ROP has changed since 2020. Primary vitrectomy was performed in case the signs listed above were identified. The transition of the disease to the inactive stage was recorded in all cases one month after primary vitrectomy. After one year the pathological process did not reactivate in any of the cases, and no pathological changes were found in the projection of the former proliferation ridge.

CONCLUSIONS

Extraretinal retinovitreal neovascularization, according to multimodal preoperative diagnostics, indicates the need for vitreoretinal surgery as a pathogenetically substantiated method of treatment for unfavorable progression of stage III active ROP.

Quercetin Attenuates Benzo(α)pyrene-induced CYP1A Expression

We studied effects of nutrient quercetin on cytochromes' Р450 1А (CYP1A) activities (measured spectrofluorimetrically using 7-ethoxy-resorufin for CYP1A1 and 7-methoxy-resorufin for CYP1A2 as substrates), on mRNA levels (measured by RT-PCR), and on DNA-binding activities (evaluated by an electrophoretic mobility shift assay) of proteins regulating CYP1A expression in untreated and benzo(α)pyrene (BaP)-treated rats. Wistar rats received quercetin, BaP, or both once daily for 1-3 days. Quercetin did not influence CYP1A1 in untreated rats but inhibited BaP-mediated CYP1A induction on the transcriptional level decreasing positive input (AhR functional activity) and increasing negative input (AhRR/ARNT expression and Oct-1 and C/EBP functional activities).

[Glial cell line-derived neurotrophic factor family ligands and their therapeutic potential]

Four glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) have been characterized: GDNF, neurturin (NRTN), artemin (ARTN) and persephin (PSPN). These proteins support and restore multiple neuronal populations such as dopaminergic, sensory, motor, hippocampal, basal forebrain, enteric, sympathetic and parasympathetic neurons. Therefore, GFLs attracted significant attention as a potential cure for the diseases caused by neuronal injury and degeneration. Results of multiple experiments indicate that GFLs can alleviate behavioral symptoms and restore affected neurons in animal models of several neurological disorders including, among others, Parkinson's disease (PD). During the last decade, GDNF protein and NRTN gene therapy have been tested in several clinical trials in patients with PD. Although the results of phase I clinical trials were positive, phase II clinical trials failed to reach primary end-points. Poor pharmacokinetic properties of GFLs (inability to penetrate tissues barriers, high affinity for extracellular matrix, etc.) could contribute to the absence of clear clinical benefits of these proteins for the patients. The purpose of this paper was to review therapeutic potential of GFLs and discuss possibilities to overcome difficulties associated with pharmacokinetic properties and delivery of GFLs to target neurons.

Effect of cold stress on expression of genes for the AhR-dependent pathway of CYP1 regulation in rat liver

The level of mRNA for cytochromes P450 (CYP1A1, CYP1A2, and CYP1B1) and CYP1 regulatory proteins (heat shock protein, aryl hydrocarbon receptor, aryl hydrocarbon receptor repressor, and aryl hydrocarbon receptor nuclear translocator) was measured in the liver of rats after cold stress (4 degrees C). The CYP1A1 mRNA level increased and remained high for 10 days after 5-day cold exposure. The level of mRNA for CYP1A2, heat shock protein, and aryl hydrocarbon receptor nuclear translocator decreased by the 10th day. The level of mRNA for CYP1B1, aryl hydrocarbon receptor, and aryl hydrocarbon receptor nuclear translocator remained unchanged over this period.

Inhibitory Effect of α-Tocopherol on Benzo(a)pyrene-Induced CYPA1 Activity in Rat Liver

Combined treatment with benzo(a)pyrene (classic inductor of cytochromes P450 of subfamily 1A, CYPA1 and CYP1A2) and alpha-tocopherol decreased benzo(a)pyrene-induced CYP1A1 activity in rat liver. Activities of CYP1A2, NADPH-cytochrome P450 reductase, and glutathione S-transferase remained unchanged under these conditions. Addition of alpha-tocopherol to benzo(a)pyrene-induced microsomes in vitro decreased activity of CYP1A1. Immunoblotting of proteins in liver microsomes with antibodies against CYP1A1 did not reveal differences in CYP1A1 protein content in the liver of rats receiving benzo(a)pyrene alone or in combination with alpha-tocopherol. The in vivo decrease in benzo(a)pyrene-induced CYP1A1 activity did not result from free radical-produced damage to CYP1A1. The inhibition of benzo(a)pyrene-induced CYP1A1 activity with alpha-tocopherol is probably realized at the posttranslational level.

Rat hepatic CYP1A1 and CYP1A2 induction by menadione

The effects of menadione on activities and expression of cytochrome P450 (CYP) 1A subfamily (CYP1A) isozymes in rat hepatic tissue were examined. When rats were treated orally with 15 mg/kg menadione for 4 days, the elevation of hepatic CYP1A1/1A2 specific activities in microsomal preparations was detected with approximately 5.4- and 2.5-fold increase over control values for ethoxyresorufin-O-deethylase (EROD, CYP1A1) and methoxyresorufin-O-demethylase (MROD, CYP1A2) activities, respectively. CYP1A1 and CYP1A2 mRNA levels in the liver of menadione-treated rats were approximately 11.8- and 1.8-fold higher than in controls, respectively, whereas the expression of the CYP1A regulatory proteins aryl hydrocarbon-receptor (AhR) and AhR nuclear translocator (Arnt) was not changed at the mRNA level. The result of this study demonstrates that menadione induces CYP1A1/1A2 expression in vivo through either transcriptional activation and/or mRNA stabilization.

Transcriptional activation of cytochrome P450 1A1 with alpha-tocopherol

Peroral administration of alpha-tocopherol in a daily dose of 150 mg/kg for 1, 4, 8, and 12 days leads to induction of cytochromes P450 1A in male rats. Activity of CYP1A1 and CYP1A2 increased most significantly one day after alpha-tocopherol administration (by 2.6 and 2.7 times, respectively). CYP1A1 was immunohistochemically detected in rat liver microsomes during this period. The content of CYP1A1 mRNA significantly increased in the liver. The amount of CYP1A2 mRNA and regulatory proteins for signal activation of CYP1A1 (AhR and Arnt) remained unchanged after treatment with alpha-tocopherol.

Dose- and time-dependent effects of menadione on enzymes of xenobiotic metabolism in rat liver

We studied the effect of synthetic vitamin K analogue menadione on enzymes of xenobiotic metabolism in rat liver (total content of cytochrome P450 and catalytic activities of CYP1A1/2, CYP2B1, CYP2C, NADPH-cytochrome P450 reductase, and glutathione S-transferase). Menadione induced phase I and II enzymes for metabolism of xenobiotics, drugs, and procarcinogens. The effect of menadione depended on its dose and duration of treatment.

Dose-dependent effect of alpha-tocopherol on activity of xenobiotic metabolizing enzymes in rat liver

Oral treatment with alpha-tocopherol for 4 days dose-dependently increased the content of cytochrome P450 (CYP), catalytic activities of CYP1A1, CYP1A2, CYP2B1, CYP2C, and activity of NADPH-cytochrome-P450 reductase in the liver of male rats, but did not change activity of glutathione S-transferase. These results suggest that alpha-tocopherol induced the enzymes of phase I of xenobiotic metabolism, including CYP1 and CYP2 families involved in the metabolism of drugs and procarcinogenes.