Age-related changes in the activity of free-radical processes in rat tissues and blood serum]

Activity of Cu,Zn-superoxide dismutase (SOD) in old rats' brain was found to be decreased by 46.8% as compared to young animals. The brain concentration of Schiff bases (SB) was decreased by 13.6% in old rats, whereas concentration of diene conjugates (DC), protein peroxidation (PP), and total antioxidative activity (TAA) was the same in old as well as in young rats. The liver level of the DC and TAA was also the same. The serum level of the PP, SB, and DC was increased whereas the activity of the SOD and TAA was decreased in old rats. The findings suggest occurrence of considerable age-related changes in free radical processes as well as the organ specifics of these changes in rats.     

Redox processes in allergic reactions of the delayed type to microbial antigens]

The influence of common allergic response of delayed type to brucellosis antigen on the processes of glycolysis and dehydrogenase activity of Krebs' cycle in guinea pigs' blood and organs was studied. Along with inhibitory activity of four dehydrogenases investigated there was a depression of the glucolysis processes connected with reduction of the lactate, pyruvate content, and with depression of the LDH activity. An increase of the anaerobic fractions and lowering of aerobic fractions content and of the spectrum excess was seen in the isoenzyme LDH spectrum.     

Redox status of the eye lens

The aim of this work was to study the regional variation of some antioxidant systems in calf lens. Specific lens regions of nearly same age were obtained by a microsectioning technique, and the concentration of reduced and oxidized glutathione, protein sulfhydryl groups and iron were measured in each lens region. The concentration of reduced glutathione, the major redox buffer in lens, exponentially decreased from the cortical regions to the nucleus. In contrast, the concentration of protein sulfhydryl groups gradually increased from the cortex toward the nucleus. The protein-bound disulfides remained constant throughout the lens. Iron was concentrated in the outer cortical region. The results show that the most dynamic redox-active zone in the lens is the subcapsular cortical region where the oxidant flux meets a highly reducing environment containing a potent redox catalyst.     

The control of humoral transport of the eye tissues]

Three series of investigations were carried out in experiments on rabbits with administration under the conjunctiva or by means of electrophoresis of lymphotrophic preparations of different mechanisms of actions with the use of a morphological marker: Gerot's mass and Indian ink jelly with subsequent histological study of the eyeball. Dalargin dilated structured liquorolymphatic drainage ducts of the eye. Terrylythin produced a selective effect on the pigment epithelium of the retina, and mannitol provided penetration of the marker into the retina neurons. Thus, it has been shown that it is possible to control selectively the humoral transport of some tissues of the eye by means of lymphotrophic agents.     

Redox processes during sensitization and allergic reaction to microbial antigens]

The effect of sensitization and delayed allergic response (DAR) to brucellosis antigen on the processes of glycolysis and dehydrogenase activity of Krebs' cycle was studied. The increasing sensitivity to Brucella was accompanied by inhibition of the dehydrogenase activity and increasing glycolysis. The changes were more pronounced in sensitization to living brucella. In DAR not only the dehydrogenase activity but also the processes of glycolysis were inhibited. Reduction of the aerobic fractions and excess of isoenzyme spectrum lactate dehydrogenase was observed both in sensitization and in DAR. Correction of biochemical shifts produced decreasing sensitization and inhibiting DAR symptoms.     

Redox enzymes in the tissues of the large intestine in the postnatal ontogeny of rats]

Using histochemical methods, age-related changes in activity of some redox enzymes in muscular and superficial layers of the mucous membrane, as well as in neurons of the myenteric nervous plexus of the large intestine have been studied in albino rats 5-day-old, 1-, 5-, 13-, 24-month-old. In young animals (1-5-month-old) an essential increase of the enzymatic activity of the energy metabolism takes place, in mature animals--stabilization of these processes, senescence brings about multidirectional changes in them. Manifestation degree of the changes in energy metabolism, occurring in old age are determined by certain metabolic and functional peculiarities in the organ tissue. In old animals certain strain of the energy metabolism develops, resulting from discoordination of energetic cycles in tissue of the large intestine wall.     

Lipids changes in rat tissues in experimental urolithiasis

Total lipids, free and ester cholesterol, triglyceride and phospholipids were determined in plasma, liver, kidney and intestine in control and calculi producing diet (CPD) fed rats. Cholesterol, phospholipids and triglycerides were increased in plasma while they were decreased in all the three tissues of CPD fed rats, compared to that of control. Distribution studies of phospholipids in the tissues of treated rats showed marked decrease in the concentration of the major lipids, i.e., PC, PE, PI and SPH. However, significant increase in absolute concentration as well as percent distribution of phosphatidic acid in kidney of treated rats was observed.     

Enzymes of cyclic nucleotide degradation in eye tissues during experimental ocular herpes

Activity of phosphodiesterases disintegrating cAMP and cGMP in the cornea, sclera and ciliary body was investigated in health and in different stages of experimental herpetic keratitis. The problems concerning the role of the cyclase system in the pathogenesis of herpetic keratitis and the possibility of applying some of the drugs to the disease treatment are discussed.     

Growth of the eye and pigment epithelium of the retina during postnatal development of rats]

By the weight changes, the rat's eye grows during the whole life, whereas its scleral sector with the area equal to that of pigment epithelium of the retina grows most intensively between the 2nd and 5th days after birth. During this period, its weight attains half of the value characteristic of the scleral sector for one year old rats. This period of growth of the scleral sector coincides with the previously established peak of proliferative activity and appearance of first binuclear cells in the pigment epithelium. From the 5th day till the 12th month after birth, the weight of scleral sector increases twice and its area 6 times. This suggests that the mechanical tension of the scleral sector walls is one of the factors of growth of this eye part. On the basis of comparison of the scleral sector growth, changes in proliferative activity and number of polyploid cells in the pigment epithelium of the central zone of fundus oculi, the following periodization of the life cycle of cell population of the pigment epithelium is proposed: (1) from birth till the 15th day--period of principal determination (the number of binuclear tetraploid cells attains 80%), (2) from the 15th day till, at least, the 5th month--period of stabilization, (3) after 5 months--period of senescence characterized by the accumulation of highly ploid tri- and tetranuclear cells; its lower limit is not clearly defined.     

Immunoactive atrial natriuretic peptide in the rat eye: molecular forms in anterior uvea and retina

Acid extracts of rat anterior uvea and retina contain immunoactive atrial natriuretic peptide. Gel filtration chromatography demonstrates that the major forms of the uveal and retinal material have approximate molecular weights of 2400 and 1750 daltons respectively, similar in size to the hypothalamic form of the peptide but clearly distinguishable from the larger, cardiac form. When further analyzed by RP-HPLC, the immunoactive material from both ocular tissues elutes at a position similar to atrial natriuretic peptide-28, again distinguishing the ocular and cardiac forms of immunoactive material. These results suggest potential roles for atrial natriuretic peptide both in ocular vegetative physiology and in retinal function.     

Concentration and comparison of adenylic nucleotides in the eye tissues of rabbits during ontogenesis]

The ATP content in the rabbit eye tissues increases from birth till the time of sight appearance (12-15th day after birth). The ADP and AMP content did not increase during the period of sight appearance. After this period, the ATP content decreased down to the level of newborn tissues. The ADP and AMP content increased in the eye tissues of 2 months old and adult rabbits.     

DNA inhibition and development of the pigment epithelium and receptors in rat retina]

In the retina of the guinea pig the outer segments of the receptor cells are damaged by cyclophosphamid, but the inner segments and the centriole are not altered. The disturbed membranes of the outer segments are incorporated by pigment epithelium. The progress of degeneration of outer segments corresponds with the increase of the number of Lysosomes in the pigmemt epithelium. The structure of mitochondria is disturbed by blocking the DNA. The unaltered mitochondria show a normal reaction of succinode hydrogenase.     

Guanidinoacetate-N-methyltransferase: location in mammalian retina and rat Harderian gland]

Homogenates of retinal external segments of rat, rabbit, beef and hen and of rat Harderian gland were found to possess a considerable activity of guanidineacetate-N-methyltransferase (GAMT, E.C. 2.1.1.2), comparable with the enzyme activity in liver, pancreas and testis. Permanent UV-illumination of rats (from 1 day to 1 week) resulted in the decrease of GAMT activity in retina and especially in Harderian gland. Caffeine (10(-4) M) and papaverine (10(-7) M) activated GAMT in retina and rat Harderian gland, while cycloheximide, a protein synthesis inhibitor (0.5-2 mkg/ml), eliminated caffeine-stimulated GAMT activity. Histamine (0.3 mkg/ml) inhibited GAMT activity both in retina and Harderian gland. A decrease of GAMT activity in retina, liver and testis of rat and an increase of the enzyme activity in rat pancreas and Harderian gland were observed in the presence of Mg2+ (5 mM). Physiological importance of GAMT and creatine in mammalian retina and rat Harderian gland is discussed.     

Effect of ionol on peroxidation processes in eye tissues and blood from rats in crush syndrome

The effect of ionole on the processes of peroxidation in the eye tissues (lens, sclera, cornea, chorioidea) and blood at crush-syndrome has been studied. For the first time in this research work the combination method of the ionole injection has been successfully tested. The ionole injection promoted a decrease in the level of lipid peroxidation products, increase in antioxidations and normalisation in the concentration of phospholipids in the eye-tissues and blood at crush-syndrome. The findings of our study based necessity of inclusion of ionole in the complex treatment of mechanical trauma with the aim of preventing the origin of posttraumatic complication in the eye region.     

Postnatal growth inhibition in the rat retina after actinomycin D adminstration]

The effects of actinomycin D on the development of the rats retina were observed. At the day of birth the inner neurons and the inner cells of the bipolar layer are vulnerable. The pale degeneration of these neurons accompanied by a dilatation of the endoplasmatic reticulum and the dark degeneration accompanied by a pycnosis and a shrinkage of the cytoplasm persist during the first 11 days after birth. The same alterations are to be seen in bipolar cells on day 11 after birth. The transient disorganisation of the inner layers could effect the ramification because the stratum reticulare internum is smaller as in untreated animals.     

Redox processes in malaria and other parasitic diseases

The role of oxidative stress resulting from production of reactive oxygen species and/or from suppression of the cellular antioxidant capacity in parasitic infections is shortly reviewed. The experimental part of the paper deals with the glutathione (GSH) — glutathione reductase (GR) system, a cornerstone of intracellular antioxidant defence mechanisms. For studying this system in parasitic diseases such as malaria new or modified methods are required. Total glutathione comprising GSH and glutathione disulphide (GSSG) in blood samples was assayed as follows. One volume of blood (10 l) is mixed with two volumes of 5% sulphosalicylic acid; after centrifugation (5 min, 10000 g), 10 l of supernatant is taken for spectrophotometric analysis using the 5,5-dithiobis(2-nitrobenzoate) (DTNB)-glutathione recycling assay. When compared with the original method, the procedure reported here is more sensitive, less time-consuming, avoids unfavourable pH-values and leads to a sample which when frozen is stable for months. In a pilot study, the method was applied to 14 patients suffering from malaria caused by Plasmodium falciparum. The concentrations of erythrocyte glutathione were significantly decreased in the patients (1.42±0.47 mM, mean±SD) when compared to age- and sex-matched controls (2.11±0.45 mM, P<0.01). The findings are contrasted with P. falciparum cultures in vitro where glutathione levels are known to be elevated. Based on the characteristics of GR a concept of determining the redox state of single cells is introduced. Microcrystals of the enzyme are expected to be suitable indicators for the intracellular redox potential since the dithiol-disulphide interconversion at the enzyme's active site is associated with a change in colour. Here we describe a simple overlay technique for crystallizing recombinant human glutathione reductase. This procedure may also be applicable to the crystallization of other proteins.This work was presented by R.H.S. at the 37th Symposium of the Society for Histochemistry (on Oxy radicals) held in Heidelberg from September 20 to 23, 1994