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Biomedical subjects

V Nováková

Publications and source records attributed to V Nováková.

At least 19 recordsLinked to original sources
PubMed1998

Brain cell RNA: sexual differences in the rat.

Sexual differences in the total content of ribosomal RNA, established by cytophotometric measurements in neurones from selected brain regions, were studied in rats of the Wistar strain. In females of reproductive age, cyclic changes of RNA were synchronized with their oestrous cycle, the values being higher in the oestrous phase than in dioestrus. These changes were observed in pyramidal cells of the hippocampus and of the frontal cortex, in cells of anterior thalamus, of ventromedial and lateral hypothalamus and of tuberculi olfactorii. However, cycling cells were not disclosed in septum and thalamus posterior. A dependence upon the actual level of ovarial hormones was found in ventromedial hypothalamic cells only. In general, the RNA values in males of the same age corresponded to values of dioestrous females. The differences between newborn and 7-day-old pups were not marked enough and did not allow to define the critical period responsible for initiation of this sexual difference. In senescent rats, this difference persisted. During the stable phase of long-lasting dioestrus, the total RNA content in cells of the frontal cortex, hippocampus and hypothalamus was higher in females than in males of the same age which may suggest a faster reduction of this substance in aged males. The prolonged influence of oestrogens in the oestrous phase of the climacteric period (preceding the permanent dioestrus) decreased the RNA values in hippocampal and hypothalamic neurones even below the level established during the permanent dioestrus (and thus reached male values). On the contrary, in frontal cortical neurones, the female values remained higher in the permanent dioestrus as well as during long-lasting oestrus. A discussion concerns the possible participation of genetic determination and of the actual state of ovarial hormones in the manifestation of sexual differences in brain cells of the rat.

Aging↗
PubMed1996

Visual evoked potential evidence for magnocellular system deficit in dyslexia.

Some recent studies on dyslexia have suggested a selective abnormality in the magnocellular visual pathway. To verify this hypothesis, we investigated motion-onset visual evoked potentials (VEPs) (predominantly testing the magnocellular system) as well as pattern-reversal VEPs (presumably testing the parvocellular system) in 20 dyslexics and 16 controls (both groups with a mean age of 10.0 years). Although the latencies and amplitudes of the main positive peak of pattern-reversal VEPs did not differ between the dyslexic and control group, the motion specific negative peak of motion-onset VEPs was significantly delayed (p < 0.001) in dyslexics. Our results confirm a selective magnocellular pathway disorder in dyslexics and indicate that the motion-onset VEPs might serve as an objective method for early diagnosis of dyslexia.

Child↗
PubMed1995

Oestrous cycle in septal rat females.

Bilateral lesions of the dorsal part of the septal area were produced in the brain of female rats of Wistar and Long-Evans stocks. The cytogram of their vaginal smears was evaluated repeatedly from the 30th day after surgery and permanent impairment of their oestrous cycle was found. In comparison with intact control females, oestrous phases were detected more frequently whereas dioestrous phases were observed less frequently. The proportions between the individual periods of the oestrous phase (i.e. pro-oestrus, oestrus and metoestrus) were equal in both septal and intact animals. No difference was found between the rat stocks used. Similarly, the previous life history of the rats which had been housed either in a socially impoverished environment (i.e. single cages) or in large communities (colonies) exerted no influence upon the postoperative impairment of the oestrous cycle.

Animals↗
PubMed1993

Maternal behaviour in septal rat females.

Dorsal lesions of the septum influenced the maternal behaviour of Wistar and Long-Evans females, as well as of their hybrids, in a different way. The phenomenon of infanticide appeared in Wistar females only, whereas mothering was not impaired in others. However, the mouse-killing activity was not enhanced in Wistar females displaying infanticide. On the contrary, they exhibited xenoparental behaviour. If these females had grown up in a species-typical environment, characterized by enriched social stimulation during their critical developmental period, no impairment of maternal behaviour following dorsal septal lesions occurred. The ablation of the whole septum caused a break-down of maternal behaviour with the appearance of infanticide in all females regardless of their stock origin and their individual life history. The specific role of the septum in the control of maternal behaviour is discussed.

Aggression↗
PubMed1993

Milk fat concentration and growth of rat pups.

The relationship between milk fat concentration and the growth of rat pups from birth to the 20th day was investigated. A total of 36 first-time-lactating Wistar rats and 366 pups from litters of 8-12 were used. The concentration of milk fat was determined by the crematocrit method, on the 2nd, 5th, 10th, 15th, 20th and 25th day of lactation. A wide range of milk fat concentration with a great variability in each individual dam was observed during lactation. To correlate milk fat and pup's growth, the mean value of the milk fat of the individual mothers was calculated for the first 10 days from the values of the 2nd, 5th and 10th day of lactation, and for the second 10 days from the values of the 10th, 15th and 20th days. The results show that pups fed higher fat milk in the first 10 days of life grew faster than pups fed lower fat milk. A significant positive correlation (P < 0.001) was found between the fat concentration of milk and the weight gains of pups in the first 10 days, but not in the older groups. It indicates that the fat concentration of milk is important for the growth of pups mainly in the early postnatal period of life.

Animals↗
PubMed1992

Influence of early undernutrition in rats on their body fat and RNA content in VMH neurons.

The RNA content of the ventromedial hypothalamus (VMH) and lateral hypothalamic area (LHA) neurons, and the epididymal, retroperitoneal, and liver fat content of 150-day-old male rats submitted to neonatal undernutrition, were investigated. The neonatal undernutrition was carried out by two different ways. First, by reducing the litters to two pups per nest from birth to weaning. The pups from normal litters (eight pups/nest) served as controls. Secondly, by separating half of the pups (four pups) from normal litters for 8 h daily during the first 5 postnatal days. The remaining nonseparated pups served as their controls. The data show that both groups of early undernourished pups had a significantly increased RNA content in the VMH neurons (RNA content in the LHA neurons was unchanged) and a significantly decreased epididymal, retroperitoneal, and liver fat content in comparison with their controls. The results indicate that early undernutrition leads to a permanent increase in the functional activity of VMH and alteration in fat metabolism in rats.

Adipose Tissue↗
PubMed1991

Influence of litter size on the RNA content of VMH and LHA in preweaning rats.

The nutritional status in the early postnatal period may significantly influence the development and functional activity of food intake regulating mechanisms. Therefore we investigated the weight gains and total RNA content of the ventromedial (VMH) and lateral (LHA) hypothalamic cells of rat pups in normal litters (8 pups/nest) and in reduced litters (2 pups/nest) reared permanently (from birth to weaning) or temporarily (from 1st to 5th day) in reduced nests. A significant decrease of weight gains was found in pups reared in reduced litters during the first 5 days which resulted in significant differences of body weight between the pups from normal and reduced litters on 5th day of life. On the 15th and 30th days, there were no significant differences in body weight between these animals, but the RNA content in VMH cells of pups reared in reduced litters was significantly increased on the 15th and 30th days. The RNA content in the LHA cells was unchanged. The results show that reducing a rat litter to 2 pups caused short-term undernutrition leading to permanent changes of the RNA content in the VMH neurons. The possible consequences of the permanently changed RNA content of this hypothalamic structure are discussed.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Ontogeny of ribonucleic acid content in rat cortical neurons influenced by early stimulation.

Developmental changes in the total RNA content were studied in pyramidal cells of the frontal, parietal (somesthetic), temporal (auditory) and occipital (visual) cortical areas in Wistar rats aged 13, 14, 15, 21, 28, 35 and 56 days, and compared with those after complex, visual and acoustic stimulation. In all areas neuronal RNA content reached peak values at the age of 3 weeks, except the parietal cortex, where the values were highest as early as at 15 days (in 21-day pups they were only insignificantly lower). Between the age of 3 and 4 weeks, RNA content of cortical neurons decreased in all three projection areas, whereas in the frontal cortex a significant decline came later--in the 5th week. In the occipital cortex neuronal RNA at 8 weeks reached reliably lower values than in 13-day pups. Neuronal RNA increased at the time of eye-lid opening (13-15 days), highly significantly in the visual cortex. Complex visual and acoustic stimulation raised neuronal RNA content in projection areas of modality involved in stimulation and, moreover, acoustic stimulation did so in the frontal and occipital cortex. On the contrary, complex and visual stimulation decreased RNA contents in the frontal cortex. Developmental dependence, stimulation contingency, and specificity vs. nonspecificity of the observed changes are discussed, and compared with other biochemical, morphological and functional changes that have been found in the period of peaking RNA content, or immediately thereafter.

Acoustic Stimulation↗
PubMed1991

[Carotenemia].

The authors demonstrate two infants with a yellow skin coloration which developed as a result of excessive dietary carotenoid intake. The yellow coloration, contrary to jaundice, did not affect the sclerae. Elevated blood carotenoid levels were found and a temporary increase of aminotransferases. In both infants lower IgA levels were recorded. After modification of the diet the yellow coloration disappeared and gradually the aminotransferases reached normal levels.

Carotenoids↗
PubMed1990

[Vitamins C and E in neonates and their mothers].

During the spring months serum levels of vitamin C and E were investigated in 49 women at the end of pregnancy and in their infants at the delivery and on the fifth day after birth. The authors found that 23.3% of the pregnant women (n = 43) who gave birth to mature, normal neonates were not adequately saturated with vitamin C during the spring months. Almost 13% of the infants (12.8%) had lower vitamin C levels on the fifth day after delivery. Two thirds of the mothers (67%) of premature infants (n = 6) had low vitamin C levels. The vitamin E levels in the pregnant women were adequate, 38% of the five-day-old infants had reduced vitamin E levels.

Ascorbic Acid↗
PubMed1990

[The effect of natural and artificial nutrition on vitamin C and E levels in the normal infant].

During the spring months the vitamin C and E serum levels were assessed in 44 normal infants. In addition the serum levels of vitamins C and E were assessed in 17 breastfed infants and their mothers. Low vitamin C levels were recorded in five infants (12.2%). Of these four were bottlefed and one infant had a mixed; mostly formula diet. Two infants with a low vitamin C level had fruit juices and strained fruit. All breastfed infants were well saturated with vitamin C despite the reduced vitamin C level of one nursing mother. Low vitamin E levels were found in two infants (4.5%). Both infants were under six weeks and were bottlefed. After supplementation of the diet with nonmilky products the vitamin E levels rose in breastfed as well as bottlefed children. In breastfed infants older than six weeks the vitamin E levels were significantly higher (p less than 0.001), as compared with bottlefed infants. The results of the investigation confirmed that only breastfeeding or well adapted cows milk formula ensure an adequate vitamin C and E level in normal infants.

Ascorbic Acid↗
PubMed1990

[Follow-up of newly diagnosed patients with diabetes in the Prague population. I. Incidence of diabetes and disorders of glucose tolerance, methods of detection, complications].

The authors followed up the incidence of new cases of diabetes in nine Prague diabetological clinics, the way of manifestation of diabetes and its detection, age dependence, seasonal character and incidence of complications. The incidence of type 2 diabetes was 269, of type 1 2.3 and impaired glucose tolerance 27 per 100,000 population. In 76% diabetes was detected accidentally, most frequently by the health community doctor or factory medical officer; 65% of the diabetes were older than 60 years. 51% suffered from hypertension and in 0.9% of type 2 diabetics retinopathy was found.

Adult↗
PubMed1990

[Follow-up of newly diagnosed patients with diabetes in the Prague population. II. Changes in the group of new diabetics after a 2-year follow-up].

From the total number of 1551 new diabetics and patients with PGT 85 subjects died in the course of two years. Treatment was changed 118 times, failure of PAD treatment was recorded in 11 type 2 diabetics. Three patients originally classified as type 1 were later included in type 2. In three diabetics (of 14) who had sings of diabetic retinopathy already during manifestation of DM marked deterioration of the finding on the fundus occurred. The incidence of macroangiopathic complications did not change.

Adult↗
PubMed1989

Coprophagy in young laboratory rat.

Coprophagy (ingestion of maternal faeces) was found in young laboratory rats between the ages of 16 and 28 days. The degree of this activity during the given period was not constant; a multiple increase on about the 25th day was followed by an abrupt drop and complete cessation coincided with the time of spontaneous weaning. Coprophagy did not appear in prematurely weaned young (at 16 days) which were given faeces and was protracted in undernourished young whose weaning time was prolonged. Young weaned rats without having ingested maternal faeces displayed relative hyperphagy for solid food. This early hyperphagy had later consequences for the feeding behaviour of adult males, which looked for food and consumed it more intensively in a new environment and also hoarded it. Defensive behaviour was not affected.

Animals↗
PubMed1988

RNA content of neurons in the ventromedial nuclei and lateral hypothalamic area relative to feeding status.

The total RNA content of hypothalamic and cortex neurons in relation to the feeding status of adult male Wistar rats was studied. Experimental conditions including food deprivation (12 and 24 hours) and relative satiation (short-term refeeding, glucose or glycerol administration) changed in different ways the total RNA content of the neurons in the ventromedial hypothalamic nuclei (VMH) and in the lateral hypothalamic area (LHA) with respect to fasting or satiety. Only the long-term absence of food (24 hours) significantly increased the total RNA content of the VMH cells, while the RNA content of the LHA neurons significantly decreased in both the 12 and 24 hr fasted rats compared with those fed ad lib. The sixty minute free access to food after 12 or 24 hours of fasting fully reversed these changes. The short-term food intake significantly increased the RNA content of the LHA cells of the 12 and 24 hr fasted animals while the total RNA content of the VMH neurons significantly decreased only in the 24 hr fasted rats. The effect of glucose and glycerol administration on the RNA content of the LHA neurons (in 12 hr fasted rats) was similar to the effect of refeeding. One hour after giving glucose (1 g/kg b.wt.) or glycerol (300 mg/kg b.wt.) the total RNA content in the LHA neurons significantly increased. No changes in RNA content were observed in the neurons of the cortex when comparing the experimental and control rats. The results demonstrated the close relationship between the RNA content of the hypothalamic neurons and the feeding status.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗