[Determination of total aminothiols and neuroactive amino acids in plasma by high performance liquid chromatography with fluorescence detection].

This paper describes a simple and sensitive reversed-phase HPLC method for the determination of total homocysteine, total cysteine, total glutathione (GSH+GSSG), and neuroactive amino acids (Asp, Glu, Tau, GABA) using precolumn derivatization with ortho-phtaldialdehyde and fluorimetric detection at 360 and 470 nm for emission and excitation, respectively. Derivatization was performed with ortho-phthaldialdehyde in the presence of 2-mercaptoethanol after alkylation of the free sulfhydryl groups with iodoacetic acid. For determination of total aminothiols, the disulfide bonds were reduced and protein-bound thiols were released by addition of dithiothreitol to the plasma sample. The advantage of this method is the simultaneous determination of both homocysteine/cysteine/glutathione and neuroactive amino acids in the sample. The plasma levels of studied compounds were determined in 14 healthy volunteers (20-45 years old) and 55 patients with chronic hepatitis C (20-49 years old) and the resulting numbers were in a good agreement the studies published earlier. The calibration curves were linear over a concentration range of 5-100 microM in plasma (r2 = 0.985-0.996). The intraday and interday coefficients of variation were 3-6% and 4-7%, respectively. The recovery of the standards added to the plasma samples ranged from 94 to 102%. The limits of detection (LOD) were 0.2-0.5 ng per 10 microl injection volume (signal-to-noise ratio of 3).

[Disruption of circadian rhythms of biogenic amines in rat hypothalamus upon administration of 1,2-dimethylhydrazine]. / Narushenie tsirkadiannykh ritmov biogennykh aminov v gipotalamuse krys pri vvedenii 1,2-dimetilgidrazina.

Levels of norepinephrine (NE), dopamine (DA) and the main metabolite of serotonin 5-hydroxyindoleacetic acid (5-HIAA) have been measured in the suprachiasmatic nuclei (SCN), preoptic area (PA), and median eminence (ME) of hypothalamus of rats after sole subcutaneous injection of 1,2-dimethylhydrazine (SDMH). Circadian changes of DA in all the brain structures under study as well as of NE in PA were observed in the control group, their levels in the mornings being higher than in the evenings; a circadian change of 5-HIAA in SCN had an opposite tendency. Both the evening (11 p.m.) and morning (11 a.m.) administrations of SDMH at the dose of 21 mg/kg body weight resulted in disturbances of all the circadian rhythms observed in control. In some cases only a 12 hrs circadian rhythms phase shift was found, in the others these rhythms of neurotransmitters disappeared entirely. The evening administration of SDMH, unlike the morning one, resulted in an increase in total NE content in the hypothalamic structures under study. It is suggested that the effect of SDMH on the levels and circadian rhythms of neurotransmitters in the hypothalamic structures under study is due to affecting activities of the enzymes of biogenic amines synthesis, synaptic transmission, melatonin synthesis and secretion rhythms, as well as to its genotoxic influence upon the genes controlling circadian actions.

[Decreased content of non-heme iron in the blood of patients with peripheral tapetoretinal abiotrophy]. / Snizhenie soderzhaniia negemovogo zheleza v syvorotke krovi u bol'nykh s perifericheskoi tapetoretinal'noi abiotrofiei.

Measurement of non-heme iron in the sera of patients with peripheral tapetoretinal abiotrophy aged 10-72 years with stages I-IV of the disease showed a statistically significant (26-30%) decrease of this parameter in comparison with healthy controls. Total iron-binding capacity of the serum was unchanged. The results are discussed with regard for previous reports about changed iron homeostasis in animals with hereditary retinal degeneration (Campbell rats) and the role of iron in the development and formation of nervous tissues.

[Changes in the electroretinogram of Campbell rats with the development of hereditary retinal degeneration]. / Izmeneniia élektroretinogrammy krys linii Kémpbell pri razvitii nasledstvennoi degeneratsii setchatki.

We studied the dependence of amplitudes of a- and b-waves of electroretinogram on intensity of light stimulus in Campbell rats with inherited retinal degeneration. On 20-th-29-th day after birth the amplitude of these waves in Campbell rats is smaller than in Wistar rats. On 30-th-40-th day response significantly decreases, down to complete disappearance of reaction. Weak response appears only to stimulus with the maximal luminance. According to decrease of amplitude of the a- and b-waves of the ERG, Campbell rats are practically blind at 40th day of postnatal life. The analysis of the form of whole ERG curve using the Fourier transformation allowed us to establish, that in Campbell rats on 20-th day after birth the amplitude of the first and second harmonics grows with increasing of stimulus luminance. At 30-th day the amplitude of the second harmonic in Campbell rats is much smaller than in Wistar rats and does not vary with increasing of stimulus luminance.