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Biomedical subjects

S Trojan

Publications and source records attributed to S Trojan.

At least 55 records · Page 3Linked to original sources
PubMed1998

Protective effect of flavonoids and tocopherol in high altitude hypoxia in the rat: comparison with ascorbic acid.

The mixture of flavonoids (silymarin) from Carduus Marianus (0.9 mg.g-1 body weight) and/or ascorbic acid (0.4 mg.g-1 body weight) were administered in the food to 21 day-old (b.w. 35-45 g) rats for one week. Then the animals were exposed, in a hypobaric chamber, to simulated altitude 8,000-12,000 m for one hour. Mean lethal altitude was calculated by the Behrens equation: it was 10,150 m in controls, 10,550 m in ascorbic acid treated, 10,500 m in silymarin and tocopherol treated and 10,450 m in animals, receiving both ascorbic acid and silymarin. Thus silymarin protected the animals against lethality of high-altitude hypoxia. The effect of ascorbic acid and silymarin were not additive.

Altitude Sickness↗
PubMed1998

[Developmental neuronal plasticity and its importance in the recovery and function of neural tissue].

Plasticity is understand as a natural ability of the nervous tissue to respond to intrinsic and extrinsic stimuli by means of functional or structural changes. All its manifestations, including the developmental changes and processes of recovery are controlled by general genetic programs. One of the major research goals in the field of neuroplasticity is to design a strategy for the activation of the functional recovery. Enough evidence has shown that the internal environment of the nervous tissue is one of the decisive factors which determine the degree of both the developmental and regenerative plasticity. To improve capacity for the recovery it is therefore necessary to activate these intrinsic neuroplastic mechanisms. One alternative is the method of implantation of the embryonal nerve cells suspension into the site of neuronal lesion. The grafted cells can either replace the lost cells or they might become a source of stimulating factors which may activate the process of recovery. In the model of the intrahippocampal pathways interruption (experimental partial elimination of granule cells in the dorsal blade of the dentate gyrus), the subsequent implantation of embryonal neurons of the same origin into the site of lesion can partly restore the structural pattern of the gyrus dentatus and probably preserve some of the afferent connections. However, the outgrow of efferent fibers probably remains limited to the grafted tissue.

Animals↗
PubMed1997

Developmental quotient at 24 months and fatty acid composition of diet in early infancy: a follow up study.

AIM: A follow up study of developmental quotient (DQ) at 24 months of toddlers whose diets in early infancy differed in fatty acid composition, and in whom an association between diet and DQ was observed at 4 months. METHODS: 81 toddlers were distributed among three groups according to early type of diets standard infant formula (SFo, n = 30); long chain polyunsaturated fatty acid (LC-PUFA) enriched formula (LCPFo, n = 26); human milk (HM, n = 25). DQ at 24 months was assessed by Brunet-Léxine's psychomotor developmental test. A subgroup (n = 20; SFo 8; LCPFo 6; HM 6) was tested for erythrocyte phosphatidyicholine and phosphatidylethanolamine. RESULTS: No DQ differences were found by analysis of variance. Neither DQ nor erythrocyte docosahexaenoic acid at 4 months were predictors of DQ scores at 24 months. Phosphatidylcholine arachidonic and docosahexaenoic acid correlated positively, and phosphatidylcholine linoleic acid and phosphatidylethanolamine eicosapentaenoic acid negatively, with DQ. Multiple regression analysis including these variables explained 52% of inter-individual DQ variance. A strong association was found between the erythrocyte phosphatidylcholine arachidonic/ linoleic acid ratio and DQ (r = 0.75; p = 0.0001). CONCLUSIONS: The diet/DQ association found at 4 months was not predictive of DQ scores at 24 months. Irrespective of dietary or genetic factors, there appears to be a strong correlation between the LC-PUFA composition of the red cell membrane and higher neurodevelopmental performance.

Breast Feeding↗
PubMed1997

[Theoretical and clinical significance of neuroplasticity].

Plasticity is a specific feature of the nervous system, characterized by two basic phenomena: The first type of "functional plasticity" develops comparatively quickly, brings about mainly functional changes and is usually reversible. The second type has the features of an adaptation and affects the expression of genotype into phenotype. Neuroplastic mechanisms are triggered by various natural or artificial stimuli which may differ quantitatively (they arise in the internal or external environment) or qualitatively. Neuroplastic mechanisms are based on modulation of the signal transmission over synapses (e.g., the transmitter release, activity of postsynaptic receptors, efficiency changes in the transmission in the postsynaptic segment). They can be related to the interneuronal relations changes (e.g., number of certain types of synapses, significance of the wiring of different elements of the neuronal circuits). Resulting changes may occur in the communication between neurons (synaptic level), in the activity of the local neuronal circuits (level of local circuits) or in the relations between individual functional brain systems (multimodular level). Neuroplasticity might be based on structural changes which can be revealed by morphological methods. Such forms of plasticity are more frequent during the development, or as a reaction to injury (proliferation and decease of neurons, formation of their processes and spines, remodelling, or formation of synapses). More specific methods have determined that these changes are located on the molecular level (enzyme activity, production and release of transmitters or modulators, receptor activation, modulation of ion channels). Both levels of neuroplastic mechanisms bring about changes of functional parameters of the synaptic transmission (changes in the duration or amplitude of the membrane potentials and resulting facilitation, posttetanic potentiation or changes of opposite character). Effects of plasticity can reside either in positive or negative changes during the development (evolutional plasticity), after a short-term exposition (reactive plasticity), after long-term or permanent stimuli (adaptational plasticity), and during functional or structural recovery of the damaged neuronal circuits (reparation plasticity). Manifestations of plasticity have probably the same basis, irrespectively of the cause which has triggered them, or the brain region where they have been accomplished. (Tab. 7, Ref. 45.)

Animals↗
PubMed1997

[The role of the basal ganglia in control of motor activity].

Morphological, histochemical and functional analysis of the role of basal ganglia in the motor control is presented. The inhibiting effect of basal ganglia on the motor activity, their role in programming the slow and stereotyped movements, and the presentation of emotional and memory centres to the motor mechanisms of behaviour is emphasised.

Animals↗
PubMed1996

Biphasic changes in the density of muscarinic and beta-adrenergic receptors in cardiac atria of rats treated with diisopropylfluorophosphate.

Chronic treatment with organophosphate inhibitors of cholinesterases is known to bring about down-regulation of muscarinic acetylcholine receptors in the heart while its effect on the functionally antagonistic beta-adrenergic receptors is not known. We describe experiments in which rats were exposed to daily injections of diisopropylflurophosphate (DFP) and the density of muscarinic and beta-adrenergic binding sites in their cardiac atria was measured according to the binding of (3H)quinuclidinyl benzilate ((3H)QNB) and (-)-4-(3-tert-butylamino-2-hydroxy)-propoxy-(5,7-3H) benzimidazol-2-one ((3H)CGP 12177) as subtype non-specific muscarinic and beta-adrenergic ligands, respectively. Biphasic course of changes was discovered with both ligands. With the dosage scheme applied, the density of beta-adrenoceptors was augmented 24 h after the first dose of DFP and decreased to about one half of control values after 5 days of treatment with DFP. The density of muscarinic receptors was augmented after two days of treatment with DFP and decreased to about one half of control values after 5 days of treatment. Comparatively small changes in the heart rate were observed during the treatment, they reflected changes in the muscarinic and beta-adrenergic receptor density. The finding of DFP-induced changes in the binding of (3H)CGP 12177 suggests that the mechanisms responsible for the control of the density of muscarinic and beta-adrenergic receptors in the heart cells are interconnected but potential roles of other factors involved in in vivo experiments deserve further analysis. The transient increase in the density of muscarinic receptors after two days of DFP treatment appears related to published data on transient stimulation by cholinergic agonists of the transcription of mRNAs for muscarinic receptors.

Animals↗
PubMed1996

Fatty acid metabolism in phenylketonuria.

Children treated for phenylketonuria (PKU) have a low intake of whole animal foods. Consequently, the dietary intake of long-chain polyunsaturated fatty acids (PUFA) is just a few milligrams per day, mostly represented by arachidonic acid (AA). In a consecutive series of studies, we assessed in treated PKU children their long-chain PUFA status, the AA-related eicosanoid synthesis and the effects of specific PUFA supplementations. We found that the good compliance with the dietary regimen negatively influences the long-chain PUFA status and serum eicosanoid release from platelets. Supplementation with either marine or blackcurrant oils modifies the long-chain PUFA status of PKU children without approaching the fatty acid pattern of a healthy control population. Good-compliant PKU patients have diet-related, low levels of circulating long-chain PUFA, whose clinical and functional consequences deserve further investigation. The effects of dietary supplementations with long-chain PUFA of both the n-6 and n-3 series should be carefully evaluated.

Adolescent↗
PubMed1996

Early breastfeeding is linked to higher intelligence quotient scores in dietary treated phenylketonuric children.

Strict control of phenylalanine intake is the main dietary intervention for phenylketonuric children. Whether other dietary-related factors improve the clinical outcome for treated phenylketonuric children in neurodevelopmental terms, however, remains unexplored. We retrospectively compared the intelligence quotient (IQ) score of 26 school-age phenylketonuric children who were either breastfed or formula fed for 20-40 days prior to dietary intervention. Children who had been breastfed as infants scored significantly better (IQ advantage of 14.0 points, p = 0.01) than children who had been formula fed. A 12.9 point advantage persisted also after adjusting for social and maternal education status (p = 0.02). In this sample of early treated term infants with phenylketonuria there was no associated between IQ scores and the age at treatment onset and plasma phenylalanine levels during treatment. We conclude that breastfeeding in the prediagnostic stage may help treated infants and children with phenylketonuria to improve neurodevelopmental performance.

Breast Feeding↗
PubMed1996

[Biocybernetics and physiology yesterday and today].

In the first part of the article authors characterize briefly the biocybernetics as a branch of science and substantiate why it should be considered as an integral constituent of biological sciences, and consequently of the physiology, too. In the second part they are paying attention to the reasons and policies for embodying selected biocybernetical subjects into the course of physiology.

Bionics↗
PubMed1995

Neurodevelopmental quotient of healthy term infants at 4 months and feeding practice: the role of long-chain polyunsaturated fatty acids.

A direct influence of dietary long-chain polyunsaturated fatty acids (LC-PUFA) on the developmental quotient (DQ) of the healthy term infant remains unexplored. To test this hypothesis, we designed a prospective study of three types of diet. Twenty-nine infants received a LC-PUFA-supplemented formula, 31 received a standard infant formula, and 30 infants were breast-fed exclusively. Neurodevelopmental response was measured by the Brunet-Lézine psychomotor development test at 4 mo. The fatty acid status was also assessed among three diet subgroups (59 subjects) at 4 mo. Formula-fed infants who received LC-PUFA supplementation scored significantly higher (p < 0.01) on the Brunet-Lézine scale than infants who received the standard formula. Breast-fed infants also performed better than those fed the standard formula. Arachidonic acid and docosahexaenoic acid levels in circulating lipids and erythrocyte phospholipids were higher among breast-fed infants and among the group fed the arachidonic- and docosahexaenoic acid-supplemented formula. These findings are suggestive that formula supplementation with one or both of these fatty acids can benefit term infants in neurodevelopmental performance.

Breast Feeding↗
PubMed1995

Growth hormone (GH) modulates insulin-like growth factor I (IGF-I) and type I IGF receptor mRNA levels in the ovary of prepubertal GH-deficient rats.

In order to explore the potential role of growth hormone (GH) in modulating insulin-like growth factor I (IGF-I) gene expression in the prepubertal rat ovary, female rats were rendered GH deficient by neonatal administration of monosodium glutamate (MSG). One group of rats received vehicle and served as the control. At 21 days of age, MSG-treated rats received either GH or vehicle for 2 weeks. On days 21, 24, 28 and 31 animals were weighed and subsets were sacrificed for liver RNA extraction. The remaining animals were sacrificed at day 35 when livers and ovaries were collected, and serum was obtained for GH determinations. The IGF-I mRNA levels were estimated by Northern blots and corroborated further by slot-blot analysis. The MSG-treated rats had lower body weights (p < 0.01) and GH levels (p < 0.05) than controls. Growth hormone replacement significantly accelerated the weight gain of MSG-treated rats. At day 24 and thereafter, three RNA IGF-I species (7.5, 1.8 and 0.8-1.2 kB) were seen in the liver. In the ovary, at age 35 days, two major IGF-I mRNA species (7.5 and 0.8-1.2 kb) were seen. The MSG treatment consistently reduced the levels of both IGF-I mRNA species in the ovary. Growth hormone administration partially restored their expression, both in the liver and in the ovary. In addition, ovarian type IIGF receptor mRNA levels were increased in the MSG-treated rats when compared to controls. This trend was reversed by GH replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Hemodynamics in the periodontium and gingiva].

Measurements of hemodynamics in parodontium and gingiva using a reflexive photoelectrical plethysmographic recorder, insensitive to salivation changes, has been described. Registration is accomplished by means of ECG recorder.

Gingiva↗