Lipoperoxidative activities in the cerebral cortex and medulla oblongata, related to age, sex, oxygen deficiency and short-term fasting.

In albino rats (Wistar), aged 10 and 14-days of postnatal life, experiments were performed, in which the intensity of lipoperoxidative processes in cerebral cortex and medulla oblongata in four experimental series was measured and compared: a) between females and males (control group); b) between females and males exposed to the hypobaric hypoxia (corresponding to the altitude of 7000 m and lasting 20 minutes); c) between females and males exposed to the short-term starvation (for 24 h between the day 5th and 6th of postnatal life); d) between females and males exposed to the combination of short-term starvation and hypobaric hypoxia. No sex-dependent differences in control measurements could be detected. The hypobaric hypoxia evokes significantly greater increase in lipoperoxidative processes in brain tissue of males as compared with females. The short-term starvation affected more the oxygen radicals production in the brain of females. Finally--the short-term starvation and the subsequent hypoxic stress did not evoke the sex-dependent differences in the brain of 10-day-old rats; in 14-day-old females the higher values in brain cortex, in males higher values in medulla oblongata were established. The different sensitiveness to mentioned stressors in males (more sensitive to oxygen deficiency) and in females (more sensitive to nutritional deficiency) was described.

[The effect of posthypoxic hypothermia for lactate dehydrogenase activity in brain cortex and blood serum of 14-days-old rats]. / Vliv a význam hypoxie a následné hypotermie na aktivitu laktátdehydrogenázy v mozkové kure a v krevním séru u 14denních laboratorních potkanu.

OBJECTIVE: The effect of various degrees of hypobaric hypoxia and consequent hypothermia on lactate dehydrogenase (E.C.1.1.1.27) activity in blood serum and brain cortex in 14 day-old rats was investigated. DESIGN: Experimental study. SETTING: Institute of Physiology, 1st Med. Faculty, Charles University, Prague. METHODS: 14 day-old rats (Wistar of our own breed) were exposed to mild hypobaric hypoxia (corresponding to altitude of 7000 m, pO2 = 8.6 kPa, BP = 41.2 kPa, lasting 20 min) or strong hypobaric hypoxia (corresponding to altitude of 9000 m, pO2 = 6.4 kPa, BP = 30.7 kPa, lasting 30 min). Just after hypoxic stress the animals were killed by decapitation and on cooled block the grey cortical matter was removed. Blood serum samples as well as brain cortex homogenates were immediately incubated in three variously tempered media (38 degrees Celsius = control values, 30 degrees Celsius and 22 degrees Celsius = hypothermic conditions). The incubation was over (30 min.), and the lactate dehydrogenase (LDH) activity was followed using the Lachema test. RESULTS: The LDH activity was influenced by mild hypobaric hypoxia (7000 m) neither in blood serum nor in brain cortex. Also the values of LDH activities registered in normo or in hypothermic conditions were not different as compared with control values. The strong hypoxia (9000 m) evokes in brain cortex homogenates simultaneously with normothermia and posthypoxic hypothermia (30 degrees Celsius) significant increase of LDH activity. In blood serum the strong hypoxia increased the LDH activity; in subsequent hypothermic condition (22 degrees Celsius) the LDH activity was more lowered. CONCLUSION: The LDH activity in brain cortex as well as in blood serum of young rats (Wistar) seems to be resistent to mild hypoxia (7000 m) as well to hypothermic conditions. The strong hypoxia (9000 m) evokes quite different responses: in brain cortex the LDH activities in hypothermic conditions are higher, in blood serum lower as compared with control values (14 day-old rats stressed by hypoxia only). In control measurements the lowering temperature decreases the mentioned enzyme activity in brain cortex; in blood serum no significant differences could be found.

[Effect of hypothermia on lactate dehydrogenase activity in blood and the cerebral cortex in 14-day-old and adult laboratory rats]. / Vliv hypotermie na aktivitu laktátdehydrogenázy v krevním séru a v mozkové kure u 14denních a dospelých laboratorních potkanu.

OBJECTIVE: In the following study, possible protective effect of hypothermia (of various degree) on brain cortex metabolic activity in very young animals and adult rats was examined. DESIGN: Experimental study. SETTING: Institute of Physiology, 1st Med. Faculty, Charles University, Prague, Czech Republic. METHODS: Homogenates of brain cortex of 14-day-old and adult rats and simultaneously blood serum were examined for lactate-dehydrogenase activity (LDH), [E.C. 1.1.1.27]. Three variously tempered incubation media (38 degrees C = control values, 30 degrees C = mild hypothermia, 22 degrees C = strong hypothermia) were checked. Also the adult rats (90-120 days) were examined (in the same arrangement). RESULTS: The LDH activity in the blood serum of 14-day-old rats under hypothermic condition was unchanged as compared with control values. In their brain cortex the hypothermia evokes a significant changes in LDH activity (mukat/l). In adult rats the results are different: no significant changes in LDH activity in the brain cortex under hypothermic condition were found, but significant drop in mentioned enzyme activity in the blood serum was established. Finally: in young animals the starting LDH activity in the blood serum as well as in the brain cortex was always significantly higher as compared with values found in adult animals. CONCLUSION: The starting higher LDH activity in the blood serum as well as in the brain cortex in young rats (as compared with adults) and the different feature of LDH changes under hypothermic conditions are considered and discussed especially with the possibility of protective action of hypothermia in hypoxic and asphyxic newborns.

[Gestational diabetes--a model trial. The effect of alloxan diabetes on the spectrum of fatty acids in the blood, liver and brain in laboratory rats]. / Gestacní diabetes--modelová studie. (Vliv aloxanového diabetu na spektrum mastných kyselin v krevním séru, v játrech a v mozku u laboratorního potkana).

In alloxan-induced diabetic rats (Wistar, females, age 3-4 months of postnatal life) the large spectrum of fatty acids in blood serum, brain cortex, medulla oblongata and liver was studied. The fatty acids, using gas chromatography, were detected as methyl esters and the methods were published previously (Smídová and al. 1994). Alloxan (Merck) administered i.p., 140 mg/kg body weight, caused immediately elevation (three times) of blood sugar levels. On the 13th day the rats were killed. The results are as follows: a) In blood serum alloxan diabetes of cca two weeks duration caused a significantly increased participation of saturated FA and decreased participation of both polyunsaturated FA (n-3 and n-6). b) In brain cortex no differences between controls and diabetic rats in the indicated groups of FA were found. c) In the medulla oblongata an increased participation of polyunsaturated fatty acids n-6 was established. d) In hepatic tissue the increased participation of saturated FA as well as a decreased participation of FA n-6 was described. Analysing the main groups of FA we found especially in n-3 and n-6 FA several significant changes in single FA (a smaller pool of arachidonic acid in blood serum as well as in liver, decreased participation of docosahexaenoic acid in the brain cortex, etc.). The purpose and possible consequences of such changes are discussed.

[Tocolysis and fatty acids]. / Tokolýza a mastné kyseliny.

To six pregnant female rats Wistar strain the beta-mimetic tocolytic preparation (Partusisten-Boehringer) was administered by the s.c. route on the 19th, 20th and 21st day of pregnancy-0.1 mg per 250 mg body weight. The above dose corresponds to clinical practice and was divided into two parts: half the amount was administered between 8 and 9 a.m., the second half between 1 and 2 p.m. To pregnant controls (mean weight 340 g) saline was administered in an analogous way. On the 22nd day of pregnancy the females with a mean weight of 330 g were sacrificed by decapitation and concurrently with collection of mixed blood the calva was opened and on a cooled block the grey matter of the brain cortex was isolated. From the foetuses pooled blood samples (from 4-5 foetuses) and samples of the CNS were collected. From each foetus 0.5 ml blood was examined. The fatty acid spectrum was assessed by gas chromatography in Base's modification (1978). It was revealed that that administration of the tocolytic to pregnant females affected most the spectrum of unsaturated fatty acids of the n-3 series. In the initial there was a statistically significant increase of linolenic acid C 18:3 n-3 values in the serum as well as in the cerebral cortex as compared with controls. In two other acids, C 18:4 and C 20:4 on the other hand, a marked drop occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

[Essential fatty acids in neonates at risk and in the mother's milk]. / Esenciální mastné kyseliny u rizikového novorozence a v materském mléce.

The participation of essential fatty acids and their derivatives in the blood (serum) of physiological healthy neonates (physiological pregnancy, physiological delivery) is compared with the spectrum of essential fatty acids of risk newborns (prematurity, prematurity with the tocolytic therapy and hypotrophic newborns). In the following part the presence and participation of essential fatty acids in the human maternal milk were measured. The milk of healthy mothers, of mothers with preterm delivery (37 week of gestation), of diabetic mothers were mutually compared and finally the values of mentioned essential fatty acids in formula Feminar and in the milk from the bank were established. As a consequence of our observations, they point out the absence or serious deficit of some essential fatty acids in certain groups of risk newborns as well as in the milk of diabetic mothers, of mothers with preterm delivery and in Feminar and Milk-bank. The presented facts--after their opinion--could be well judged as a rational basis for adequate nutritional therapy in risk newborns.

[Fatty acids in the serum of hypotrophic neonates]. / Mastné kyseliny v séru hypotrofických novorozencu.

Using gas chromatography, Carlo Erba 2531 measurements were performed and the composition of serum fatty acids in 9 hypotrophic human newborns (the mean birth = 2184 g, the mean gestation age = 39 weeks) was evaluated. Fatty acids were detected as methylesters and their levels were compared with fatty acids levels of control healthy neonates born at term (n = 32). In the hypotrophic newborns the content of saturated fatty acids (short and medium-chain in particular) significantly increased, the total amount of polyunsaturated fatty acids (PUFA) series n-3 and n-6 significantly decreased and the proportion of arachidonic acid remained unchanged in comparison with the control group.

[Serum fatty acids in premature neonates]. / Mastné kyseliny v séru predcasne narozených novorozencu.

In the past we have published several papers concerning the evolution of large spectrum of fatty acids in the brain or in the blood-serum in rats or in human newborns (and their mothers just after the delivery). Therefore we realized this study: the blood-serum spectrum of fatty acids in the healthy human newborns (n = 32) was compared with the spectrum of fatty acids detected in the blood-serum of human premature neonates (n = 22). The birth-weight in the control group was 3,882, in the premature neonates 2,137 g only. Fatty acids were measured as methylesters (FAME) using the method of gas chromatography and absolutely the same methodological approach as in our previous studies (33, 22, 23). The results were computed by biocybernet. dep. of Physiological institute and the statistics were evaluated by Mann-Whitney U test. It was established that the premature neonates show a distinct greater content (expressed in percentage) of saturated fatty acids and a smaller share of polyenoic FA (PUFA). A further marked difference consists in a significant lower of the n-3 FA and consequently a higher n-6/n-3 index. In premature neonates a significant increase of caprylic acid and arachidonic acid in the blood-serum was detected. The significance of described changes in the participation of single fatty acids in the premature neonates for their maturation, structural evolution especially of the brain cells and for therapy, is discussed.

[The spectrum of fatty acids during lactation in women]. / Spektrum mastných kyselin v prubehu laktace u zeny.

The large spectrum of fatty acids (expressed in relative values) was studied in the breast-human milk during the first three weeks of the lactation (3rd, 5th, 10th and 20th day after delivery). All women passed the pregnancy and the delivery without any pathological syndrome and their neonates were found as a healthy and physiological too. No drug dependency was registered. Fatty acids were measured as methyl-esters (FAME) using the method of gas chromatography (1). During the 20 days after delivery and of lactation period, summarising the groups of fatty acid (saturated, monoenoic, PUFA n-3, n-6 and n-9) only few changes could be detected: the increase of the participation of saturated fatty acids of short-medium chain (8:0, 10:0 and 12:0) and of PUFA n-9. Compared with the most administered commercial formula Feminar, the visible differences in the participation of fatty acids were described. Finally: during the lactation we could obtain a large number of significant differences of such individual fatty acids as palmitic acid, arachidonic acid, eicosopentaenoic acid, linoleic acid ect. The possible reasons of such changes during the lactation are discussed and these results are compared with our previous data concerning the fatty acid- spectrum in blood plasma of healthy newborns and preterm or hypoxic infants.

Hypoxia and fatty acids in immature nervous tissue in the rat.

In experiments on 2-day-old rats (Wistar strain, our own breed), we studied the effect of altitude hypoxia (9000 m, 60 min) on the proportion of individual fatty acids in the brain (the cortex+the diencephalon+the cranial third of the mesencephalon). We found that hypoxia significantly altered the proportion of the various fatty acids, with a significant increase in the proportion of group n-3 polyenoic fatty acids at the expense of saturated and monoenoic acids. The results fully confirm the conception that one of the most important mechanisms responsible for the high resistance of new born mammals to oxygen deficiency is the ability of immature nervous tissue to activate, in particular, elongation (the elongation of fatty acids) and/or lipogenetic processes.

[The fatty acid spectrum in the serum of mothers and infants after premature delivery]. / Spektrum mastných kyselin v séru matek a detí po predcasném porodu.

Using the method of gas chromatography on a Carlo Erba 2531 apparatus in Base's modification, the authors identified serum fatty acids of mothers (n = 23) and premature infants (17 girls and 6 boys). The mean birth weight was 2224.3 (800-2650 g), the mean gestation age 34 weeks (28-37 weeks). The fatty acid levels were compared with fatty acid levels of control mothers (n = 7) and control healthy neonates born at term (n = 15). Individual fatty acids were expressed as the ratio in the total volume of fatty acids (100%). The neonates and their mothers were divided into three groups. The most numerous group (n = 12) are mothers who lost the amniotic fluid prematurely (6 hours-12 days), mothers under the influence of Partusisten (n = 10); the third group is formed by mothers treated with ATB (n = 8). In these groups the authors assessed, as compared with controls, the rise of the saturated fatty acid ratio, in particular short-chain fatty acids. The greatest increase was recorded in mothers and children under the influence of Partusisten. The ratio of mono- and polyunsaturated n-6 fatty acids was not altered in the infants, there was, however, a marked reduction of the n-3 fatty acid ratio which are known to play an important role in the regulation of immune responses and to have an anti-inflammatory effect; they are also important for the development of the CNS and retina.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effect of repeated fasting on the ratio of individual fatty acids in the brain and blood of rats of various ages]. / Vliv opakovaného hladovení na zastoupení jednotlivých mastných kyselin v mozku a v krevním séru ruzne starých krys.

In locally bred, 5-day old and full grown rats, the authors conducted experiments where they investigated the influence of repeated fasting (3 X 18 hours food deprivation on three consecutive days) on a wide spectrum of fatty acids in the cerebral cortex, medulla oblongata and serum. The fatty acids were assessed as methyl esters by gas chromatography, as described in previous work (1, 13, 14, 17). In 5-day old rats after repeated fasting an evident decline in the ratio of saturated fatty acids in serum was recorded; at the same time the ratio of arachidonic acid increased markedly and in the cerebral cortex there was a significant drop of the palmitic acid participation. In adult rats 16 statistically significant changes took place (treble as compared with the 5-day old rats). The large number of significant changes pertained to 18 carbon fatty acid (a rise in all instances in the brain; the ratio of 18:3n-6 in plasma declined significantly). In the serum of adult rats the ratio of arachidonic acid increased also. The authors discuss possible reasons of the described changes.

Proportion of individual fatty acids in the non-esterified (free) fatty acid (FFA) fraction in the serum of laboratory rats of different ages.

In experiments on Wistar strain rats of both sexes, aged 5, 10 and 14 days and adult (90-120 days), of their own breed, the authors determined the quantitative proportion of individual fatty acids in the serum free non-esterified fatty acid (FFA) fraction, using mixed blood (obtained by decapitation) and the titration method of Trout et al. (1960). The proportion of the individual fatty acids was then determined in this fraction by gas chromatography (Base 1978) and their concentration (in mumol.1-1) was determined by simple calculation from the relative chromatogram data. Animals in the first three age groups were killed in the morning, directly from the nest; in adult rats the FFA fraction was measured after a 20 h fast. It was demonstrated that the increase in the proportion of monoenoic acids was highly statistically significant (about fivefold) during ontogenesis and that there was also a marked increase in the quantitative expression of polyenic acids, especially in group (n-6). The n-6/n-3 acid index in the FFA fraction altered during maturation (despite some fluctuation it basically rose from 4.3 in 5-day-old young to 10.0 in adult rats). It was further demonstrated that the concentration of fatty acids with a very short chain fell significantly during development, so that C 8:0, for example, could be detected only in the first two age groups, but not in 14-day-old and adult rats. The concentration of the saturated fatty acids C 15:0 to C 18:0 in the serum FFA fraction showed a statistically significant increase, while the index expressing the ratio of saturated to unsaturated fatty acids displayed a downward trend during development.

Fatty acid values in the plasma of neonates, umbilical cord and maternal blood.

The proportion of a wide range of fatty acids was studied in the plasma of 15 healthy newborn infants following a physiological pregnancy and delivery. The same measurements were done in seven healthy mothers (immediately after parturition) and the proportion of fatty acids was analysed in mixed umbilical cord blood (n = 7). The fatty acids were identified by gas chromatography as their methyl esters (FAME). In newborn infants the proportion of saturated fatty acids was found to be 42.3%, of monoene fatty acids 31.3% and of polyene fatty acids 25.4%; type n-6 fatty acids formed 13.9% and n-3 11.1%. The proportion of the various fatty acids in healthy maternal plasma was 37.9% (saturated), 34.4% (monoene) and 25.0% (polyene) respectively; type n-6 fatty acids formed 21.6% and type n-3 only 3.6%. The values in mixed cord blood were 44% (saturated FA), 34.8% (monoene FA) and 20% (polyene FA); group n-6 FA accounted for 17.4% and n-3 for only 2.1%. In the above three series we also described the sequence of the fatty acids present in the largest amounts. This is part of an extensive study, in a large series, of the commonest perinatal risks. We particularly draw attention to the high proportion of long-chain fatty acids (C 22 - C 26) in the plasma of healthy newborn infants.

Effect of acute altitude hypoxia on fatty acid proportion in the plasma of rats of different ages.

Using gas chromatography, the authors studied the development of the proportion of 25 saturated and non-saturated fatty acids in the plasma of Wistar rats of their own breed aged 5, 10, 14 and 25 days and adult (both sexes), and in three age groups (5 and 14 day and adult) they determined the effect of acute altitude hypoxia. Fatty acids were determined as methylesters (FAME) (Base 1978), using the method already described by Smídová et al. (1984a), in mixed blood plasma obtained from decapitated control and experimental animals. Altitude hypoxia, which corresponded to 9 000 m, lasted 20 min. The temperature was kept stable at 25 degrees C. Marked changes occurred during ontogenesis in the proportion of total fatty acids (TFA) in the plasma; the proportion of sigma non-saturated FA fell significantly during maturation, chiefly in favour of monoene FA, with a resultant significant drop in their reciprocal index (sigma saturated/sigma monoene). The proportion of all saturated FA amounted in 5-day-old rats to 54% of the total quantity, but in adult rats to only 40%. Acute hypoxia had a demonstrable effect in all three age categories. In 5-day-old rats it led to significant changes in 7 FA and in adult rats in 10. In both 5-day-old and adult animals it produced an increase in the arachidonic acid level. The results are discussed in relation to previous findings on the effect of the same hypoxia on FA proportion in various parts of the CNS of rats of different ages.

Developmental fatty acid changes in different parts of the rat brain.

The proportion of 26 fatty acids (FA) in the lipids of the cerebral cortex, subcortical formations (the thalamus, hypothalamus and basal ganglia) and the medulla oblongata was studied in rats aged 5, 10, 14 and 90 days. Very marked developmental changes in the proportion of the various FA were demonstrated in the different parts of the brain. In the cerebral cortex the proportion of 17:1 rose by 285%, 18:3 n-3 by 1820% and 22:6 n-3 by 80%, while the proportion of 14:0, 16:0 and 16:1 fell significantly. In the tissue of subcortical formations we found an increase in the proportion of FA with 18 carbons (18:0 by 40%, 18:1 by 100%, 18:3 n-3 by over 5000%) and a decrease in the proportion of 14:0, 16:0, 16:1 and 20:4 n-6. The situation in medulla oblongata tissue was similar to the one in subcortical formations. On comparing the proportion of FA in individual parts of the CNS in the same age category, we found the smallest number of statistically significant differences in 5-day-old rats. In adult rats we found significant differences chiefly in the proportion of palmitic acid (16:0), oleic acid (18:1), linolenic acid (18:3 n-3) and acids with 20-22 carbons.