[Conjugates of pancreatic ribonuclease and ligand-free human serum albumin]. / Kon''iugaty pankreaticheskoi ribonukleazy s bezligandnym syvorotochnym al'buminom cheloveka.

Conjugates of pancreatic RNase and ligand-free human serum albumin (LFHSA) have been obtained. The number of hydrophobic binding sites both for initial HSA and LFHSA has been determined by the polarised luminescence method. Interaction between RNase and HSA involves additional electrovalent linkage. Unlike initial enzyme, conjugates exhibit activity toward double-strand RNA. After intravenous injection, transferase activity of unmodified enzyme remains in the blood during 20 min., whereas 30-40% of this activity is detected at the fourth day after administration of RNase conjugates. A single dose administration of LFHSA-RNAse conjugates exhibited high antiviral activity in mice, infected with influenza A and influenza B viruses.

[Permeation of pancreatic ATPase through the blood-brain barrier into the cerebral parenchyma]. / Proniknovenie pankreaticheskoi RNKazy cherez gematoéntsefalicheskii bar'er v parenkhimu mozga.

Penetration of exogenous RNAases, native and albumin polymer-bound, from circulation into the brain parenchyma was studied. Native pancreatic RNAase was found to extend through the hematoencephalic barrier; maximal enzymatic activity was detected within 15-30 min after administration into a rat tail vein. The enzyme activity was not observed within 90 min both in blood serum and brain tissue. The conjugate of RNAase and human albumin with molecular mass of 300,000 penetrated through the hematoencephalic barrier. Maximal enzymatic activity was estimated within 3-5 hrs after administration and maintained rather high within 24 hrs in blood and brain parenchyma. This suggests that the preparations of this kind are promising in experimental medicine.

[DNAse-I inhibition by the chromatin proteins of the brain cells in rats]. / Ingibirovanie DNKazy-I belkami khromatina kletok golovnogo mozga krys.

The effect of protein extracted from nuclei of brain cells on the reaction of DNA-ethidium bromide complex interaction with DNAase I and Bac. subtilis nuclease was studied. The nuclei were isolated from the brain of Wistar male rats weighting 180-200 g. The fluorescence was recorded on a Hitachi MPF-44B spectrofluorimeter. Proteins extracted from the nuclei with 0.6 NaCl substantially inhibited the DNAase I but not Bac. subtilis nuclease activity. Other studied fractions of nuclei lacked the capacity for inhibiting DNAase I.

[Levels of immunoreactive insulin in the pancreas and allograft to the anterior chamber of the eye in experimental diabetes]. / Soderzhanie immunoreaktivnogo insulina v podzheludochnoi zheleze i allotransplantate v peredniuiu kameru glaza pri éksperimental'nom diabete.

Transplantation of the embryonic pancreas to an immune privileged area (the anterior chamber of the eye) ensures considerable improvement of the condition of animals with alloxan diabetes. Some results concerning graft functioning for a long period of time and partial regeneration of insulin-producing tissue of the pancreas of operated on animals were obtained.

[Compensation in behavioral disorders in rats receiving 5,7-DHT neonatally and by transplantation of embryonic raphe nucleus tissue]. / Kompensatsiia narushenii povedeniia krys, neonatal'no poluchavshikh 5,7-DOT, putem transplantatsii émbrional'noi tkani iader shva.

In 62 male Wistar rats the influence was studied of the transplanted embryonal tissue of raphe nuclei (NR) on the mechanisms of compensation of disturbances of exploratory activity, sensory attention, learning and emotional reactivity induced by neonatal injection of 5,7-DHT. In histochemical studies by Falk-Hillarp method the presence of yellow fluorescence confirmed the specificity of transplanted 5-HT neurones. It is found that NR transplantation causes in animals after 3 months recovery of orienting reaction to sensory stimuli, reduces rats reactivity in the open field, restores the ability to discrimination of emotionally positive influence, disturbed by neonatal injection of 5,7-DHT. The obtained data show the possibility of compensation of behaviour disturbances caused by chronic deprivation of 5-HT system activity by transplantation in the neocortex parenchyma of the embryonal tissue, containing serotoninergic neurones.

[The level of noradrenaline and serotonin in mice differing in behavior]. / Uroven' noradrenalina i serotonina u myshei, razlichaiushchikhsia po povedeniiu.

Laboratory mice possessing Robertsonian translocation Rb (8, 17) 1IEM in their karyotype, reveal statistically significant ability for extrapolation of the direction of stimulus movement which disappears from animal's view. Inbred CBA mice with the same translocation are less capable, and CBA mice with normal karyotype are totally incapable of solving this task. Cortical noradrenaline levels in mice with Rb (8, 17) 1IEM were the lowest and brain stem levels the highest among the three groups investigated. Serotonin levels reveal no changes among these groups.

[L-DOPA interaction with the brain tissue DNA of rats]. / Vzaimodeistvie L-DOFA s DNK tkani goloovnogo mozga krys.

The possibility of direct interaction of L-DOPA with DNA isolated from rat brain tissue has been considered. The spectral and viscosity data suggest conformational changes in L-DOPA-treated DNA in conditions excluding the accumulation of L-DOPA oxidation products.

[Effect of catecholamines and serotonin on RNA-synthesizing activity in isolated nuclei and chromatin of the rat brain and liver]. / Vliianie katekholaminov i serotonina na RNK-sinteziruiushchuiu sposobnost' izolirovannykh iader i khromatina mozga i pecheni krys.

It has been shown that intraperitoneal injections of L-DOPA cause an increase in the matrix activity of chromatin and stimulate the incorporation of [3H]uridine into the nuclear fraction of rat brain cells by 35%. In vitro studies have shown that preincubation of brain chromatin with L-DOPA diminishes the inhibiting effect of actinomycin D on RNA synthesis. It has been found that the rate of RNA synthesis in vitro depends on concentrations of catecholamines (L-DOPA, dopamine, norepinephrine) and serotonin.

[Characteristics of the complex formation of L-DOPA with chromatin elements from brain cells]. / Kharakteristika kompleksoobrazovaniia L-DOFA s élementami khromatina kletok mozga.

It was found that L-DOPA interacts with brain cell chromatin. The life-time of the chromatin-L-DOPA complex is the greatest at 24 degrees C, while at 37 degrees C the destruction of the complex is observed. The specific binding is about 40% at pH 7.4-7.6. The Kd value calculated by the method of Scatchard is equal to 35.10(-9) M. Treatment of the chromatin-L-DOPA complex with DNAase I decreases the chromatin radioactivity by 15-20%. At the same time pronase treatment decreases the chromatin radioactivity by 80%. NaCl (0.2 and 0.4 M) causes the extraction of more than 70% of 3H-DOPA in the complex with chromatin proteins. Thus, L-DOPA interacts predominantly with chromatin proteins.

[Mechanism of action of DNAse from the rat brain]. / Mekhanizm deistviia DNKazy golovnogo mozga krys.

The mechanism of action of exodeoxyribonuclease from rat brain predominantly localized in neuronal nuclei was studied. The enzyme which is highly specific towards one-chain DNA can effectively hydrolyze the two-chain DNA of plasmid pBR 322 "activated" by the disruption of the phosphodiester bond in one chain. A kinetic analysis of DNA hydrolysis with a tritium label evenly distributed along the DNA molecule and terminally labeled with phosphate revealed that the enzyme hydrolyzes polynucleotides from the 5'-to the 3'-end via a partially processive mechanism.

[DNA repair in mammalian nerve cells. I. DNA synthesis in the neocortex of rats induced by gamma irradiation]. / Reparatsiia DNK v nervnykh kletkakh mlekopitaiushchikh. I. Sintez DNK v neokortekse, indutsirovannyi gamma-oblucheniem krys.

A study was made of the DNA synthesis in cerebral cortex of rats, aged 14 and 60 days, after gamma-irradiation in vivo in a dose of 7 Gy, the 3H-thymidine incorporation into DNA being determined.137 Cs-radiation induces additional DNA synthesis in the neocortex tissue and in neurons. In the cortex of 14 day-old rats, the induced DNA synthesis stops 2 hours after irradiation, whereas in the cortex of 60 day-old rats and in neurons of rats of both the age groups DNA synthesis is proceeding for 3-3.5 hours. Specificity of DNA reparation processes in non-dividing cells is discussed.

[Nuclear DNAse from rat brain]. / Iadernaia DNK-aza kletok golovnogo mozga krys.

Nuclear DNase specific for single-stranded DNA was obtained from the rat brain. The enzyme was isolated from a soluble protein fraction of total cell nuclei using gel filtration and ion-exchange chromatography. Nuclear DNase is Mg2+-dependent exodeoxyribonuclease and hydrolyzes homological, heterological and synthetic substrate at the same rate. It is established that nucleoside-5'-monophosphates are the major product of native and synthetic polydeoxyribonucleotides hydrolysis. It is supposed that the enzyme participates in reparation of neuron DNA.

[Characterization of DNAse from rat brain]. / Kharakteristika DNKazy golovnogo mozga krys.

Using gel filtration and ion exchange chromatography, a DNAse specific to a single-stranded DNA was isolated from the soluble fraction of rat brain nuclear proteins. The nuclear nuclease corresponds to alkaline DNAse obtained earlier from the intact brain. The enzyme is a Mg2+- or Mn2+-dependent exodeoxyribonuclease and hydrolyzes at the same rates the ss-DNAse from rat brain, calf thymus, E. coli and poly (dA). The major products of hydrolysis are nucleoside-5'-monophosphates. A possible role of the enzyme in reparation of neuronal DNA is discussed.