Occurrence of manganese, copper and zinc in myelin. Alterations in the peripheral nervous system of dysmyelinating trembler mutant are at variance with brain mutants (quaking and shiverer)

Mn, Cu and Zn were present in mouse brain at concentrations that were 54, 4 and 14 times higher than in serum. In comparison with control animals, Mn was nearly normal in both quaking and shiverer dysmyelinating mutants. Cu was slightly higher in shiverer; Zn was higher in quaking only when expressed on a dry weight basis. The peripheral nervous system contained lower amounts of Mn, Cu and Zn than brain, (1 6 , 1 8 and 1 2 respectively). All three metals were much higher in trembler (4, 3 and 2-fold increase, respectively). Although higher in shiverer and quaking, Mn did not differ significantly from control. Cu and Zn were similar to control in the sciatic nerve of quaking and shiverer. Brain myelin contained Mn, Cu and Zn concentrations that were slightly smaller than those found in the whole brain. Mn and Cu were higher in the myelin from shiverer by approx. 2- and 3-times, whereas Zn was two-fold reduced. It is speculated that such metals play a role in membrane as cofactors of enzymes, especially those in control of free radical damage, and possibly also in membrane structures as phospholipid counterions.

Alteration of ethanolamine glycerophospholipid turnover in trembler dysmyelinating mutant: An analysis of the sciatic nerve by biochemistry and radioautography

The turnover of phospholipids was compared in peripheral nerves of Trembler dysmelinating mutant and control mice, after intraperitoneal and local injection of labeled ethanolamine. In the mutant sciatic nerve, neurochemical analysis showed that [(14)C]ethanolamine is incorporated into EGP (ethanolamine glycerophospholipids) of the sciatic nerve at a much higher rate in Trembler mutant than in control mice. Furthermore the decay rate of (14)C-labeled EGP is faster in Trembler than in normal animals. The accelerated turnover of EGP in Trembler sciatic nerve affects the diacyl-EGP while the renewal of the alkenylacyl-EGP (plasmalogens) is slower than in controls. Quantitative radioautographic study at the ultrastructural level corroborate that the initial increase of the label in Trembler nerve fibers was different in axons, Schwann cells and myelin sheaths. EM radioautographs reveal indeed that the high label content observed in Trembler axons takes place preferentially in the myelinated portions of axons and drops within 1 week. In both myelinated and unmyelinated segments of the axons, the majority of the radioactivity was contained in axolemma and smooth axoplasmic reticulum. The 10-fold increase of label found in the myelin sheath of Trembler nerve fibers at 1 day raises the question of the origin of the labeled EGP, either by a stimulated synthesis in Schwann cells or by transfer from axonally transported phospholipids. In contrast, the label of axons, Schwann cells and myelin sheaths of control nerve remains stable during the same period.

[Penile verrucous carcinoma]

Penile verrucous carcinoma is a rare tumor. Verrucous carcinoma is thought by most to represent a well-differentiated or low-grade squamous-cell carcinoma. The term Buschke-Lowenstein tumor and giant condyloma have also been used to identify this histological lesion. A review of literature points to the role of human papillomavirus infection. The authors report a case of a penile verrucous carcinoma in a circumcised man.

[Urachal adenocarcinoma]

The authors report a case of mucinous adenocarcinoma of the urachus treated with partial cystectomy. The urachal cancer is an uncommon clinicopathologic entity associated with a poor prognosis. Anatomical considerations, clinical features and treatment are discussed.

Dietary oleic acid not used during brain development and in adult in rat, in contrast with sciatic nerve

In order to determine exactly the effect on the nervous system of concentration of dietary oleic acid on the fatty acid composition of different part of the nervous system, triglycerides were synthesized using chemical and enzymological methods. The dose-effect was determined using an experimental protocol with seven groups of rats who received a diet in which the oleic acid level varied from 0 to 6000 mg per 100 g diet, but the other ingredients were identical (in particular the essential fatty acids, linoleic and alpha-linolenic acid). Rats were fed the diets from two weeks before mating, and their pups were sacrificed aged either 21 or 60 days. When the level of oleic acid in the diet was increased, the main modifications observed in 21-day-old deficient animals were as follows. (i). For 18:1(n-9), in liver, plateau was reached at about 4 g oleic acid per 100 g diet. Below this level, the higher the dose the greater the response. In whole brain, brain myelin, and nerve endings (but not sciatic nerve) the oleic acid level remained optimal and constant whatever the level of oleic acid in the diet. (ii). 16:1(n-7) concentration decreased in liver and in sciatic nerve, but not in nervous tissue. (iii). In 60-day-old animals, results were generally similar to those in 21-day-old animals.

The administration of pig brain phospholipids versus soybean phospholipids in the diet during the period of brain development in the rat results in greater increments of brain docosahexaenoic acid

Dietary porcine brain phospholipids are much more efficient than soybean phospholipids for ensuring a normal (optimal obtained with lab chow diet) level of docosahexaenoic acid (DHA) in tissues and brain subcellular fractions (brain myelin and nerve endings). Two weeks before mating, rats were divided into two groups (one group was subdivided into subgroups, fed with varying amounts of porcine brain phospholipids; the other group was divided into subgroups fed varying amounts of soybean phospholipids). Pups were killed when 21 days old. DHA (22:6(n-3)) increased up to normal levels in parallel with increasing amounts of (n-3) fatty acids (omega-3 fatty acids) in the diet, up to 60 mg with dietary porcine brain phospholipids and up to 200 mg with soybean phospholipids. Thus a smaller amount of dietary brain phospholipids resulted in the same level of DHA in tissues as a larger amount of dietary soybean phospholipids. In contrast, 22:5(n-6) declined when (n-3) fatty acids in the diet increased. It stabilized at 60 mg of (n-3) fatty acids/100 g diet with brain phospholipids, and approximately 200 mg/100 g diet with soybean phospholipids. As 22:5(n-6) replaced DHA in tissue when (n-3) fatty acids were not sufficient in the diet, this result shows that the recovery of a normal (and minimal) amount of 22:5(n-6) was obtained with lower dietary levels of brain phospholipids compared with soybean phospholipids.

[Prospective randomized single-blind trial comparing oral sodium phosphate with polyethylene glycol for colonoscopy preparation]

AIM AND METHODS

The aim of this prospective, randomized, study performed in 60 outpatients was to compare 2 precolonoscopy bowel preparations: oral sodium phosphate (NaP) versus standard polyethylene glycol-based lavage solution (PEG). None of the patients met any of NaP exclusion criteria. All patients were prepared on the day prior to colonoscopy. A patient-questionnaire and measure of serum electrolytes (calcium, phosphate, sodium, potassium), pulse and blood pressure were used to assess tolerance and acceptability of the preparation. The quality of colon cleansing was judged by blinded endoscopists.

RESULTS

Patient's tolerance to NaP was superior to PEG: NaP preparation was easier to drink and feelings of abdominal plenitude occurred in a smaller proportion of patients. A potassium decrease, a sodium increase and hyperphosphatemia were observed in the NaP group but without clinical events. PEG preparation seemed to allow a better cleansing ability compared with NaP but this difference was not statistically significant.

CONCLUSIONS

NaP solution was better tolerated and accepted by patients. Colonic preparation quality compared to PEG is still to be discussed depending on the intake schedule. A biochemical data check seems necessary on account of significant serum electrolytes changes induced by NaP preparation.

Vitamin E deficiency has different effects on brain and liver phospholipid hydroperoxide glutathione peroxidase activities in the rat

The effect of vitamin E deficiency on glutathione peroxidase activity (GPX) and on the activity of a selenoenzyme (phospholipid hydroperoxide glutathione peroxidase (PHGPX) was measured in rat brain and liver. In brain, the activity of both enzymes was in the same range in homogenate and in microsomes. In contrast, in liver homogenate, PHGPX activity was approximately 20 times lower than that of GPX. Very interestingly, PHGPX activity was significantly decreased in brain microsomes by vitamin E deficiency, but slightly significantly increased in liver microsomes. In contrast, GPX activity was not affected in brain by vitamin E deficiency, but was significantly lower in liver homogenate and microsomes. Thus, PHGPX activity is partially controlled by vitamin E in membranes, and PHGPX is probably an enzyme different from GPX.

Possible role of the choroid plexus in the supply of brain tissue with polyunsaturated fatty acids

Delta-6 desaturase was measured in rat brain microvessels and choroid plexus by incubation in the presence of radioactive linoleic acid. Under our conditions, in 21-day-old animals, delta-6 desaturase was not detected in brain microvessels. In contrast, it was present in choroid plexus (about 21 pmol/min per mg protein). In comparison, the activity in brain was much lower (about 1 pmol/min per mg protein) and higher in liver (about 55 pmol/min per mg protein). Interestingly, during development the activity in choroid plexus peaked at day 6 after birth and declined slightly thereafter. The pattern of incorporation of linoleic acid radioactivity was not the same in choroid plexus and microvessels. These results show that delta-6 desaturase was not detected in brain microvessels but was present in choroid plexus.

Does an increase in dietary linoleic acid modify tissue concentrations of cervonic acid and consequently alter alpha-linolenic requirements? Minimal requirement of linoleic acid in adult rats

Rats were fed a control diet containing both linoleic and alpha-linolenic acid. When 60-days-old they were divided into 8 groups, each receiving the same amount of alpha-linolenic acid, but varying amounts of linoleic acid. When the (n-6)/(n-3) ratio in the diet varied from 2 to 32 (with a constant amount of 150 mg alpha-linolenic acid per 100 g diet), tissue levels of the (n-3) series fatty acids were not significantly modified, except in the liver, heart and testes. In all organs studied, the saturated and monounsaturated fatty acids were practically unchanged. For the (n-6) series fatty acids, arachidonic acid was not significantly affected, in muscle, kidney, brain, myelin, nerve-endings or sciatic nerve, whatever the quantity of linoleic acid in the diet. In liver, arachidonic acid plateaued at 2400 mg linoleic acid/100 g diet and at 400 mg/100 g diet in heart. Results for 22:5(n-6) showed a marked increase in heart, a moderate increase in liver and kidney, and no effect in muscle, testes, brain, myelin, nerve-endings or sciatic nerve. This experiment defined the minimum amount of linoleic acid required in the diet to maintain fatty acids of the linoleic family in the young adult rat. For the first time it was demonstrated that 1200 mg/100 g diet are sufficient for the liver, as evidenced by maintenance of the arachidonic acid concentration. For the other organs, there is either a very marked preservation of this acid, or the dietary level is less than 300 mg/100 g diet. For the essential fatty acid precursors (i.e. linoleic and alpha-linolenic acids), the optimal (n-6)/(n-3) ratio required in the diet is about 8.

[Mid-term failure of balloon dilatation treatment of antral stenosis induced by caustics]

We report the case of an antral stricture following lye ingestion. The patient was treated by 3 dilations using a through-the-scope balloon dilator, initially with good results. One year later, the recurrence of the symptoms led to 2 other sessions of dilation without success and a partial gastrectomy was performed. The intensity of the gastric wall fibrosis on the surgical specimen, probably responsible for major motor impairment, accounts for the discordance between the good endoscopic result and the clinical failure. Endoscopic dilation of lye-induced gastric strictures could be a temporary alternative to surgical resection because the gastric wall fibrosis blemishes the long-term functional result.

Comparison of recovery of previously depressed hepatic delta 6 desaturase activity in adult and old rats

The ability to recover hepatic delta 6 desaturase (delta 6D) activity with linoleic acid as substrate was compared in adult and old rats. Male rats fed a diet deficient in alpha-linolenic acid were used either at 6 or 21 months. From these two ages onward, animals were fed a diet containing 10% fish oil for 3 months to reduce delta 6D activity. After this period, some of the animals were killed. The other animals were returned to the original diet deficient in alpha-linolenic acid. Fatty acid composition in liver and brain and hepatic delta 6D activity were analysed 3 and 7 days after the change in diet. When rats were fed the diet containing 10% fish oil, delta 6D activity was lower than in those fed the diet deficient in alpha-linolenic acid. The liver fatty acid composition was altered with disappearance of 22:5 n-6 and a decrease in 18:2 n-6, 20:4 n-6 and 22:4 n-6 accompanied by an increase in 20:5 n-3, 22:5 n-3 and 22:6 n-3. When rats were re-fed the original diet, delta 6D activity returned after 3 days to its initial level in the 9-month-old rats; in 24-month-old animals, recuperation was incomplete. The level of 20:4 n-6 and 18:2 n-6 increased in the liver concurrently with a decrease in levels of 20:5 n-3, 22:5 n-3 and 22:6 n-3. In both age groups, the brain fatty acid profile remained unchanged 7 days after returning to the diet deficient in alpha-linolenic acid.

Incorporation of trans long-chain n-3 polyunsaturated fatty acids in rat brain structures and retina

During heat treatment, polyunsaturated fatty acids and specifically 18:3n-3 can undergo geometrical isomerization. In rat tissues, 18:3 delta 9c,12c,15t, one of the trans isomers of linolenic acid, can be desaturated and elongated to give trans isomers of eicosapentaenoic and docosahexaenoic acids. The present study was undertaken to determine whether such compounds are incorporated into brain structures that are rich in n-3 long-chain polyunsaturated fatty acids. Two fractions enriched in trans isomers of alpha-linolenic acid were prepared and fed to female adult rats during gestation and lactation. The pups were killed at weaning. Synaptosomes, brain microvessels and retina were shown to contain the highest levels (about 0.5% of total fatty acids) of the trans isomer of docosahexaenoic acid (22:6 delta 4c,7c,10c,13c,16c,19t). This compound was also observed in myelin and sciatic nerve, but to a lesser extent (0.1% of total fatty acids). However, the ratios of 22:6 trans to 22:6 cis were similar in all the tissues studied. When the diet was deficient in alpha-linolenic acid, the incorporation of trans isomers was apparently doubled. However, comparison of the ratios of trans 18:3n-3 to cis 18:3n-3 in the diet revealed that the cis n-3 fatty acids were more easily desaturated and elongated to 22:6n-3 than the corresponding trans n-3 fatty acids. An increase in 22:5n-6 was thus observed, as has previously been described in n-3 fatty acid deficiency. These results encourage further studies to determine whether or not incorporations of such trans isomers into tissues may have physiological implications.

Comparison of liver microsome enzyme and fatty acid composition recovery in adult and old rats deficient in 18:3n-3 refed a diet containing 18:3n-3

The effect of dietary n-3 deficiency on liver microsome enzymes activities and fatty acid composition was studied in adult (3 months old) and old rats (18 months old). At these two ages, deficient animals were refed with 18:3n-3 diet for 1 or 2 months and the recovery of these parameters was investigated. Cytochrome P 450 level was decreased by n-3 PUFA (Polyunsaturated fatty acid) deficiency. After refeeding, it returned to control values after 1 month. NADH-cytochrome b5 reductase activity was decreased, the activities of NADPH cytochrome c reductase, aminopyrine demethylase, aniline hydroxylase were also decreased, but in old rats they were increased by refeeding. N-3 PUFA deficiency caused a decrease of 18:2n-6 and 22:6n-3 and an increase in 20:4n-6, 22:5n-6 and 18:1n-9. After refeeding, in adult rats, the PUFA level remained lower; in old rats, the MUFA (Monounsaturated fatty acid) and PUFA levels returned to control values. Liver microsomal enzyme activities depend on the degree of unsaturation of fatty acids rather than the specific species of polyunsaturated fatty acids.

Dietary alpha-linolenic acid at 1.3 g/kg maintains maximal docosahexaenoic acid concentration in brain, heart and liver of adult rats

We have previously determined the dietary alpha-linolenic requirement for membrane synthesis in the developing animal. This study measures the dietary requirement for maintaining normal membrane composition in adult rats, as determined by 22:6(n-3) (docosahexaenoic acid) concentration. Sixty-day-old rats, previously fed a diet containing both linoleic and alpha-linolenic acid, were divided into nine groups, each receiving different quantities of alpha-linolenic acid but the same amount of linoleic acid. They were killed 4 wk after initiation of the new diet to determine the minimum quantity of alpha-linolenic acid required in the diet for maintaining the 22:6(n-3) tissue concentration in brain (whole tissue, myelin and nerve endings), liver and heart. The minimal amount of dietary alpha-linolenic acid that maintained the maximal 22:6(n-3) level and minimal 22:5(n-6) level in tissues was considered to be the dietary requirement. The quantity was found to be 1.30 g/kg diet (0.26% of dietary energy). It was lower than that found for the developing animal (0.4% of energy). At lower quantities of dietary alpha-linolenic acid, 22:6(n-3) was replaced by 22:5(n-6) in the organs examined, except in nervous tissue, in which 22:6(n-3) was highly preserved.

Brain phospholipids as dietary source of (n-3) polyunsaturated fatty acids for nervous tissue in the rat

In a previous work, we calculated the dietary alpha-linolenic requirements (from vegetable oil triglycerides) for obtaining and maintaining a physiological level of (n-3) fatty acids in developing animal membranes as determined by the cervonic acid content [22:6(n-3), docosahexaenoic acid]. The aim of the present study was to measure the phospholipid requirement, as these compounds directly provide the very long polyunsaturated fatty acids found in membranes. Two weeks before mating, eight groups of female rats (previously fed peanut oil deficient in alpha-linolenic acid) were fed different semisynthetic diets containing 6% African peanut oil supplemented with different quantities of phospholipids obtained from bovine brain lipid extract, so as to add (n-3) polyunsaturated fatty acids to the diet. An additional group was fed peanut oil with rapeseed oil, and served as control. Pups were fed the same diet as their respective mothers, and were killed at weaning. Forebrain, sciatic nerve, retina, nerve endings, myelin, and liver were analyzed. We conclude that during the combined maternal and perinatal period, the (n-3) fatty acid requirement for adequate deposition of (n-3) polyunsaturated fatty acids in the nervous tissue (and in liver) of pups is lower if animals are fed (n-3) very long chain polyunsaturated fatty acids found in brain phospholipids [this study, approximately 60 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 130 mg/1,000 kcal] rather than alpha-linolenic acid from vegetable oil triglycerides [200 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 440 mg/1,000 kcal].

Function of dietary polyunsaturated fatty acids in the nervous system

The brain is the organ with the second greatest concentration of lipids; they are directly involved in the functioning of membranes. Brain development is genetically programmed; it is therefore necessary to ensure that nerve cells receive an adequate supply of lipids during their differentiation and multiplication. Indeed the effects of polyunsaturated fatty acid (PUFA) deficiency have been extensively studied; prolonged deficiency leads to death in animals. Linoleic acid (LA) is now universally recognized to be an essential nutrient. On the other hand, alpha-linolenic acid (ALNA) was considered non-essential until recently, and its role needs further studies. In our experiments, feeding animals with oils that have a low alpha-linolenic content results in all brain cells and organelles and various organs in reduced amounts of 22:6(n-3), compensated by an increase in 22:5(n-6). The speed of recuperation from these anomalies is extremely slow for brain cells, organelles and microvessels, in contrast with other organs. A decrease in alpha-linolenic series acids in the membranes results in a 40% reduction in the Na-K-ATPase of nerve terminals and a 20% reduction in 5'-nucleotidase. Some other enzymatic activities are not affected, although membrane fluidity is altered. A diet low in ALNA induces alterations in the electroretinogram which disappear with age: motor function and activity are little affected but learning behaviour is markedly altered. The presence of ALNA in the diet confers a greater resistance to certain neurotoxic agents, i.e. triethyl-lead. We have shown that during the period of cerebral development, there is a linear relationship between brain content of (n-3) acids and the (n-3) content of the diet up to the point where alpha-linolenic levels reach 200 mg for 100 g food intake. Beyond that level there is a plateau. For the other organs, such as the liver, the relationship is also linear up to 200 mg/100 g, but then there is merely an abrupt change in slope and not a plateau. By varying the dietary 18:2(n-6) content, it was noted that 20:4(n-6) optimum values were obtained at 150 mg/100 g for all nerve structures, at 300 mg for testicle and muscle, 800 mg for the kidney, and 1200 mg for the liver, lung and heart. A deficiency in ALNA or an excess of LA has the same main effect: an increase in 22:5(n-6) levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Structural and functional importance of dietary polyunsaturated fatty acids in the nervous system

The nervous system is the organ with the second greatest concentration of lipids. These lipids participate directly in membrane functioning. Brain development is genetically programmed. It is therefore necessary to ensure that nerve cells receive an adequate supply of nutrients, especially of lipids, during their differentiation and multiplication, and throughout their lives. The effects of polyunsaturated fatty acid deficiency have been extensively studied; prolonged deficiency leads to death in animals. Linoleic acid is now universally recognized to be an essential nutrient. Until recently, however, alpha-linolenic acid was considered non-essential. Feeding animals with oils that have a low alpha-linolenic content results in all brain cells and organelles and various organs having reduced amounts of 22:6n-3, which is compensated for by an increase in 22:5n-6. The speed of recuperation from these anomalies is extremely slow for brain cells, organelles, and microvessels, in contrast to other organs. A decrease in alpha-linolenic series acids in the membranes results in a 40% reduction in the Na(+)-K(+)-ATPase of nerve terminals and a 20% reduction in 5'-nucleotidase. Some other enzymatic activities are not affected, although membrane fluidity is altered. A diet low in alpha-linolenic acid induces alterations in the electroretinogram which disappear with age; motor function and activity are little affected, but learning behavior is markedly altered. The presence of alpha-linolenic acid in the diet confers a greater resistance to certain neurotoxic agents (triethyl-lead). During the period of cerebral development, there is a linear relationship between brain content of n-3 acids and the n-3 content of the diet up to the point where alpha-linolenic levels reach 200 mg for 100 g of food intake. Beyond that level there is a plateau. For other organs, such as the liver, the relationship is also linear up to 200 mg/100 g, but then there is merely an abrupt change in slope and not a plateau. When dietary 18:2n-6 content was varied, it was noted that 20:4n-6 optimum values were obtained at 150 mg/100 g for all nerve structures, 300 mg for testicle and muscle, 800 mg for kidney, and 1200 mg for liver, lung and heart. A deficiency in alpha-linolenic acid and an excess of linoleic acid have the same main effect: an increase in 22:5n-6 levels.(ABSTRACT TRUNCATED AT 400 WORDS)

Dietary linoleic acid and polyunsaturated fatty acids in rat brain and other organs. Minimal requirements of linoleic acid

Starting three weeks before mating, 12 groups of female rats were fed different amounts of linoleic acid (18:2n-6). Their male pups were killed when 21-days-old. Varying the dietary 18:2n-6 content between 150 and 6200 mg/100 g food intake had the following results. Linoleic acid levels remained very low in brain, myelin, synaptosomes, and retina. In contrast, 18:2n-6 levels increased in sciatic nerve. In heart, linoleic acid levels were high, but were not related to dietary linoleic acid intake. Levels of 18:2n-6 were significantly increased in liver, lung, kidney, and testicle and were even higher in muscle and adipose tissue. On the other hand, in heart a constant amount of 18:2n-6 was found at a low level of dietary 18:2n-6. Constant levels of arachidonic acid (20:4n-6) were reached at 150 mg/100 g diet in all nerve structures, and at 300 mg/100 g diet in testicle and muscle, at 800 mg/100 g diet in kidney, and at 1200 mg/100 g diet in liver, lung, and heart. Constant adrenic acid (22:4n-6) levels were obtained at 150, 900, and 1200 mg/100 g diet in myelin, sciatic nerve, and brain, respectively. Minimal levels were difficult to determine. In all fractions examined accumulation of docosapentaenoic acid (22:5n-6) was the most direct and specific consequence of increasing amounts of dietary 18:2n-6. Tissue eicosapentaenoic acid (20:5n-3) and 22:5n-3 levels were relatively independent of dietary 18:2n-6 intake, except in lung, liver, and kidney. In several organs (muscle, lung, kidney, liver, heart) as well as in myelin, very low levels of dietary linoleic acid led to an increase in 20:5n-3.(ABSTRACT TRUNCATED AT 250 WORDS)

Delta 6 desaturase in brain and liver during development and aging

delta 6 Desaturase was measured in the mouse brain and liver using linoleic acid as substrate. During pre- and postnatal development, delta 6 desaturase in brain decreased dramatically (12-fold) up to postnatal day 21 and remained nearly constant thereafter. In liver, the activity increased approximately 9-fold between day 3 before birth and day 7 after birth. Then it decreased slightly up to weaning and was approximately constant up to 4 mo. From then on, delta 6 desaturase decreased with age (40% between 4 and 17 mo).

Effect of increasing amounts of dietary fish oil on brain and liver fatty composition

Increasing dietary fish oil in rat had the following effect on brain lipids: Arachidonic acid regularly decreased; eicosapentanenoic acid, normally nearly undetectable, was present; 22:5(n - 3), dramatically increased but remained below 1% of total fatty acids; cervonic acid was increased by 30% at high fish oil concentration. Saturated and monounsaturated fatty acids were not affected regardless of chain-length. In contrast, in the liver, nearly all fatty acids (saturated, monounsaturated and polyunsaturated) were affected by high dietary content of fish oil, but liver function was normal: serum vitamin A and E, glutathione peroxidase, alkaline phosphatase, transaminases were not affected. Serum total cholesterol, unesterified cholesterol and phosphatidylcholine were slightly affected. In contrast, triacylglycerols were dramatically reduced in proportion to the fish oil content of the diet.

The effects of dietary alpha-linolenic acid on the composition of nerve membranes, enzymatic activity, amplitude of electrophysiological parameters, resistance to poisons and performance of learning tasks in rats

Feeding rats diets containing oils that have a low alpha-linolenic acid [18:3(n-3)] content, such as sunflower oil, results in reduced amounts of docosahexaenoic acid [22:6(n-3)] in all brain cells and organelles compared to rats fed a diet containing soybean oil or rapeseed oil. During the period of cerebral development there is a linear relationship between the n-3 fatty acid content of the brain and that of food until alpha-linolenic acid represents approximately 200 mg/100 g food [0.4% of the total dietary energy for 18:3(n-3)]. Beyond that point brain levels reach a plateau. Similar values are also found for other organs. The level of 22:6(n-3) in membranes is little affected by the dietary quantity of linoleic acid [18:2(n-6)] if 18:3(n-3) represents approximately 0.4% of energy. In membranes from rats fed diets containing sunflower oil, Na+, K(+)-ATPase activity in nerve terminals was 60%, 5'-nucleotidase in whole brain homogenate was 80%, and 2',3'-cyclic nucleotide 3'-phosphodiesterase was 88% of that in membranes from rats fed diets containing soybean oil. A diet low in alpha-linolenic acid leads to anomalies in the electroretinogram, which partially disappear with age. It has little effect on motor activity, but it seriously affects learning tasks as measured with the shuttle box test. Rats fed a diet low in alpha-linolenic acid showed an earlier mortality in response to an intraperitoneal injection of a neurotoxin, triethyltin, than did rats fed a normal soybean oil diet.

High dietary fish oil alters the brain polyunsaturated fatty acid composition

Feeding adult rats a 17% corn-oil diet for 8 weeks did not change brain polyunsaturated fatty acids (PUFA) compared to rats fed 2.2% corn oil (with 2.2% lard added). When the corn-oil diet was supplemented with 14.5% cod liver oil or 12.5% salmon oil, the fatty acid composition of brain PUFA was significantly altered, even if alpha-tocopherol was added to the salmon-oil diet. Comparing salmon-oil- and cod-liver-oil-fed animals with corn-oil-fed animals, arachidonic acid 22:4(n-6) and 22:5(n-6) were reduced, and 20:5(n-3), 22:5(n-3) and 22:6(n-3) were increased. Liver fatty acids were also significantly altered. Thus, the brain is not protected against a large excess of very-long-chain n-3 PUFA, which increase n-3/n-6 ratio and could lead to abnormal function, and which might be difficult to reverse.

Alterations of lipid synthesis in the normal and dysmyelinating trembler mouse sciatic nerve by heavy metals (Hg, Pb, Mn, Cu, Ni)

Lipid synthesis from 14C-labeled acetate was dramatically reduced by inorganic mercury in the mouse sciatic nerve in vitro (IC50 was 10 microM). The dysmyelinating trembler mutant was less affected (IC50 was 40 microM). Under the same conditions, lipid synthesis was less inhibited by inorganic lead but was increased 3 times by manganese, copper and nickel at less than 2 mM. Although the synthesis of all lipids is dramatically reduced by inorganic mercury, their relative proportions vary in the presence of this metal:cholesterol synthesis was inhibited most strongly, phosphatidylcholine synthesis was also reduced, whereas synthesis of other lipids was relatively unchanged (phosphatidylserine, phosphatidyl inositol, sphingomyelin, cholesterol esters, cerebrosides). Incorporation of [14C]acetate into free fatty acids was enhanced by a factor of 4 in the presence of inorganic mercury.

Biochemical and physicochemical determinations in a premyelin fraction obtained by zonal centrifugation in normal mouse and in dysmyelinating mutants (quaking, shiverer, and myelin-deficient)

Myelin and premyelin material denser than myelin were obtained from quaking (Qk), shiverer (Shi), and myelin-deficient (mld) mutant and control mice, using zonal centrifugation on zonal rotor. On these fractions, we performed biochemical analysis (lipids and fatty acid), and, in parallel, we determined the physical structure of membranes by the spin-label method. The hyperfine splitting constant (2 Tll) was used to determine the order of membranes and their rigidity, and frequency of rotation (Vc) was used to measure fluidity. In control mice, the premyelin material contained a lesser amount of sphingolipids than pure myelin, but the relative proportions between hydroxy- and nonhydroxy-cerebroside and sulfatides were similar in the premyelin material and in pure myelin. The premyelin material contained half the alkanes found in the pure myelin and much less very-long-chain fatty acids. The (2 Tll) was lower in the premyelin material, but the (Vc) was similar in myelin and premyelin material. In mutants, the amount of material recovered in the premyelin fraction was reduced in qk, and increased in both shi and mld. The relative amount of sphingolipids were normal in mld, but not in shi mutants, especially in cerebrosides formed with alpha-hydroxylated fatty acids and sulfatides formed with unsubstituted fatty acids. The absolute amounts of sphingolipids were nearly normal in both shi and mld. In the premyelin fraction from qk mutants, both relative and absolute amounts of sphingolipids were drastically altered. In percentage, cerebrosides and sulfatides formed with nonhydroxyfatty acids were dramatically reduced, and, conversely, cerebrosides and sulfatides formed with hydroxyfatty acids were increased. In terms of absolute amount, only cerebrosides and sulfatides formed with nonhydroxyfatty acids were dramatically reduced. In the premyelin fraction, polyunsaturated fatty acids were increased in shi and mld, but decreased in qk. In this mutant, lignoceric (24:0) and nervonic (24:1) acids were drastically reduced. The amount of alkanes in the premylin material from qk and mld was reduced by 50%. The shi fraction was nearly free of alkanes. The maximal apparent coupling constant (hyperfine splitting constant, 2 Tll) was not affected in the mld and qk mutant, but was reduced in the shi mutant premyelin fraction. The Vc was dramatically increased in the qk, slightly decreased in the shi, and close to control in the mld. This work provides additional data on premyelin material prepared in various neurological mutants using continuous gradients in zonal rotor.(ABSTRACT TRUNCATED AT 400 WORDS)

Recovery of altered fatty acid composition induced by a diet devoid of n-3 fatty acids in myelin, synaptosomes, mitochondria, and microsomes of developing rat brain

Rats were fed a semisynthetic diet containing either sunflower oil or soya oil. Half the litter fed with sunflower oil diet was changed to a soya oil diet when the pups were 15 days old (during active myelination). Fatty acid analysis was then performed on subcellular fractions of the animals fed (a) soya oil, (b) sunflower oil, and (c) soya oil replacing sunflower oil from the 15th day, to determine the speed of the recovery. All material from animals fed sunflower oil showed an important reduction in docosahexaenoic acid (22:6 n-3), compensated by an increase in docosapentaenoic acid (22:5 n-6), whereas arachidonic acid (20:4 n-6) was not affected. In all fractions examined, when sunflower oil was replaced by soya oil in 15-day-old pups the recovery started from the very first day but lasted more than 2 months (this recovery was determined by the increase of 22:6 n-3 up to the normal value and decrease of the 22:5 n-6). In addition a delay was found for myelin recovery, starting only from the 25th day.

Changes in fatty acid elongation in developing mouse brain by mercury--comparison with other metals

Hg2+ dramatically altered microsomal synthesis of very long chain fatty acids specific for myelin in mouse brain, as measured by lengthening of behenyl-CoA by means of malonyl-CoA in vitro. This alteration was found with Cu2+, but not with various other metal ions, showing that changes in fatty acid synthesis could be due to the alteration of sulphydryl groups.

Case of dementia and myoclonia in an adult associated with anomalies in polyunsaturated fatty acids in leukocytes and peripheral nerve. An ultrastructural study of peripheral nerve

We report a case of a 66-year-old patient presenting with abnormal movements and associated dementia. Death occurred 4 years after the onset of symptoms. In spite of the lack of autopsy results, the picture was one of late onset neuronal ceroid lipofuscinosis (Kufs' disease). Ultrastructural study of a peripheral nerve biopsy sample indicated a process of demyelination associated with unusual inclusions in Schwann cell cytoplasm. Biochemical analysis of the same sample and leukocytes showed considerable alterations in polyunsaturated fatty acid levels. These findings are discussed in the light of work on cases of infantile neuronal ceroid lipofuscinosis.

Alteration of sulfatide synthesis in control and Trembler mice during Wallerian degeneration and remyelination

Sulfatide synthesis from sulfate is much greater in the peripheral nerves of the Trembler mouse. After nerve transection, during Wallerian degeneration, this synthesis rate drops down very rapidly in both normal and Trembler mice. Twenty-four hours after permanent transection, the rate of synthesis is reduced by 80% in the mutant and 50% in the normal mouse. Four days after transection, the synthesis rate in the Trembler is only 9% of that observed in intact nerves, and 21% of that in the intact nerves of normal animals. After 5 d the synthesis remains constant. Thus, enhanced synthesis of sulfatides in the Trembler mouse is probably not caused by Wallerian degeneration. After crush of the sciatic nerve, the synthesis rate decreases very rapidly in the normal mouse as it does after permanent transection. But during regeneration, from the 7th day, it rises dramatically and 14 d after crush, a 2.5-fold increase in the synthesis rate is observed, compared to that in the contralateral control nerve. This synthesis rate returns to normal 1 mo after crush. In the Trembler, the synthesis decreases for 2 d after crush and increases from then on, eventually reaching the value of the contralateral control Trembler nerve within 2 mo. In the mutant there is no prominent peak of sulfatide synthesis during regeneration.

Alterations in the fatty acid composition of rat brain cells (neurons, astrocytes, and oligodendrocytes) and of subcellular fractions (myelin and synaptosomes) induced by a diet devoid of n-3 fatty acids

Rats were fed through four generations with a semisynthetic diet containing 1.0% sunflower oil (6.7 mg/g n-6 fatty acids, 0.04 mg/g n-3 fatty acids). Ten days before mating, half of the animals received a diet in which sunflower was replaced by soya oil (6.6 mg/g n-6 fatty acids, 0.8 mg/g n-3 fatty acids) and analyses were performed on their pups. Fatty acid analysis in isolated cellular and subcellular material from sunflower-fed animals showed that the total amount of unsaturated fatty acids was not reduced in any cellular or subcellular fraction (except in 60-day-old rat neurons). All material from animals fed with sunflower oil showed an important reduction in the docosahexaenoic acid content, compensated (except in 60-day-old rat neurons) by an increase in the n-6 fatty acids (mainly C22:5 n-6). When comparing 60-day-old animals fed with soya oil or sunflower oil, the n-3/n-6 fatty acid ratio was reduced 16-fold in oligodendrocytes, 12-fold in myelin, twofold in neurons, sixfold in synaptosomes, and threefold in astrocytes. No trienes were detected. Saturated and monounsaturated fatty acids were hardly affected. This study provides data on the fatty acid composition of isolated brain cells.

Effect of polyunsaturated fatty acids on fetal mouse brain cells in culture in a chemically defined medium

The biochemical and morphological effects of polyunsaturated fatty acids on fetal brain cells grown in a chemically defined medium were studied. Fetal brain cells were dissociated from mouse cerebral hemispheres taken on the 16th day of gestation. After cells had grown in chemically defined medium for 8 days, the proportion of polyunsaturated fatty acids of cultured cells was only one-half of that observed at day 0 and about 1.5 times less than that of cells grown in serum-supplemented medium. Fatty acid 20:3(n-9) was present in cultured cells grown in either chemically defined or serum-supplemented medium, demonstrating the deficiency of essential fatty acids. The reduced amount of polyunsaturated fatty acids in cells grown in the chemically defined medium was balanced by an increase in monounsaturated fatty acids. The saturated fatty acids were not affected. When added at the seeding time, linoleic, linolenic, arachidonic, or docosahexaenoic acid stimulated the proliferation of small dense cells. Besides, we demonstrate that each of the four fatty acids studied was incorporated into phospholipids. Adding fatty acids of the n-6 series increased the content of n-6 fatty acids in the cells, but also provoked an increase in the n-3 fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of the linolenic acid content of the mother's diet on the polyunsaturated fatty acid composition of subcellular fractions in brain development in the rat]

In order to determine precisely the respective roles of linolenic acid and linoleic acid in the maternal diet on rat brain subcellular fractions during development, we used two diets with different percentages of linolenic acid (18:3 n-3). The animals were fed peanut oil (group A) or soybean oil (group B) during pregnancy and throughout lactation. Nature and amount of essential fatty acids had no incidence on saturated and monounsaturated fatty acid distributions in myelin, synaptosomal, mitochondrial and microsomal fractions. In adult rats, all subcellular fractions are marked by an increase of n-3 fatty acid and a decrease of n-6 fatty acid levels in group B compared to group A. In 15-day-old animals, on the contrary, only the synaptosomal fractions are significantly affected by the diet. Independent of diet, brain development is marked by a decrease of n-6 fatty acids in all subcellular fractions; on the other hand, the n-3 fatty acid level is increased in the synaptosomal and mitochondrial fractions, and decrease in the myelin and microsomal fractions. The sum of (n-3 + n-6) fatty acids remains constant in group B and in group A in all subcellular fractions. Finally, under our experimental conditions, we found no marked effect of diet composition upon linoleic acid conversion to arachidonic acid; only the delta 4-7-10-13-16-docosapentaenoic acid (22:5 n-6) level decreased in group B. delta 7-10-13-16-19-Docosapentaenoic acid (22:5 n-3) seemed to be a better substrate for delta 4 desaturase than delta 7-10-13-16-docosatetraenoic acid (22:4 n-6).

Alteration in fatty acid composition of neurons, astrocytes, oligodendrocytes, myelin and synaptosomes in intrauterine malnutrition in rat

Intrauterine growth retardation (IUGR) was obtained by ligation of one uterine artery on day 17 of pregnancy. Neurons isolated from IUGR rats presented a decrease of monounsaturated fatty acids and an increase of omega-3 serie fatty acids, concomitant to a decrease of omega-6 serie fatty acids. Oligodendrocyte content in monounsaturated fatty acids was also reduced; important modifications occurred in their polyunsaturated fatty acid distribution. Myelin was close to normal in adults, slightly altered in young. Synaptosomes presented slight disturbances in polyunsaturated fatty acid distribution. Thus, the fatty acid composition was an index of maturation stage and nutritional status of developing brain membranes.

Intrauterine growth retardation (malnutrition by vascular ligation) induces modifications in fatty acid composition of neurons and oligodendrocytes

Intrauterine growth retardation (IUGR) induced by ligation of one uterine artery on day 17 of pregnancy in the rat lead to major abnormalities in the fatty acid content of neurons and oligodendrocytes but not in astrocytes. In neurons from IUGR rats, monounsaturated fatty acids were decreased; in the polyunsaturated series, omega-3 fatty acids were increased and omega-6 fatty acids were decreased. In oligodendrocytes, monounsaturated fatty acids were also decreased, but the modifications in polyunsaturated fatty acids were the opposite of those in neurons: omega-3 being decreased and omega-6 increased. Although the animals received a normal diet after birth, the alterations were still present in adulthood. In addition, fatty acid composition of brain cells is a very indicative criterion of brain maturation.

Lipid metabolism in peripheral nerve cell culture (rich in Schwann cells) from normal and trembler mice

A culture of peripheral nerve cells, very rich in Schwann cells, was developed from sciatic nerve. In both normal and Trembler, typical spindle-shaped cells were seen; most of the cells were surrounded by basement membrane-like material (predominantly in-between adjacent cells). In Trembler cells, cultivated in the presence of labelled acetate, the fatty acids were slightly altered; phosphatidylcholine was slightly reduced and phosphatidylethanolamine increased. Sulfatides were increased four times.

Influence of intrauterine malnutrition on brain development: alteration of myelination

As compared to other organs, in intrauterine growth retardation brain is less affected; however, forebrain weight and total lipids are reduced. Myelin quantity is reduced by 27, 17, 9 and 6% at 15, 18, 30 and 60 days after birth, respectively. Thus, intrauterine undernutrition followed by normal diet after birth affects myelination, a postnatal event. Prenatal growth retardation moderately but irreversibly impairs brain maturation, whereas the composition of myelin during maturation is close to normal (when density profile, lipid amount and the fatty acid pattern are considered).