Effect of sublethal concentrations of waterborne copper on lipid peroxidation and enzymatic antioxidant response in Gambusia holbrooki

The aim of the current research was to assess the possible influence of copper sulphate contamination on the antioxidant enzymatic defenses and lipid peroxidation (LPO) in the mosquitofish (Gambusia holbrooki). Quadruplicated lots of this fish were exposed to three increasing sub-lethal concentrations of Cu (0.10; 0.17 and 0.25mgCu/L) and a control without Cu for 20 days. Previous to laboratory acclimation, 8 fish were taken to define the initial population. At the end of the trials, 12 fish/sex/treatment were sampled for the determination of levels of copper in gills, metallothioneins (MTs) content, total lipids, fatty acids profiles and antioxidant enzymatic activity, as well as lipid peroxidation. Most of the antioxidant enzymatic defenses assayed were not activated and lipid peroxidation decreased significantly in fish exposed to any concentration of copper applied. This leads us to presume the existence of a protective mechanism against peroxidation other than the enzymatic antioxidant defense, which could be related to the observed increase of copper content in the gills.

Exogenous alkaline phosphatase treatment complements endogenous enzyme protection in colonic inflammation and reduces bacterial translocation in rats

Alkaline phosphatase (AP) inactivates bacterial lipopolysaccharide and may therefore be protective. The small intestine and colon express intestinal (IAP) and tissue nonspecific enzyme (TNAP), respectively. The aim of this study was to assess the therapeutic potential of exogenous AP and its complementarity with endogenous enzyme protection in the intestine, as evidenced recently. IAP was given to rats by the oral or intrarectal route (700U/kgday). Oral budesonide (1mg/kgday) was used as a reference treatment. Treatment with intrarectal AP resulted in a 54.5% and 38.0% lower colonic weight and damage score, respectively, and an almost complete normalization of the expression of S100A8, LCN2 and IL-1β (p<0.05). Oral AP was less efficacious, while budesonide had a more pronounced effect on most parameters. Both oral and intrarectal AP counteracted bacterial translocation effectively (78 and 100%, respectively, p<0.05 for the latter), while budesonide failed to exert a positive effect. AP activity was increased in the feces of TNBS colitic animals, associated with augmented sensitivity to the inhibitor levamisole, suggesting enhanced luminal release of this enzyme. This was also observed in the mouse lymphocyte transfer model of chronic colitis. In a separate time course study, TNAP was shown to increase 2-3 days after colitis induction, while dextran sulfate sodium was a much weaker inducer of this isoform. We conclude that exogenous AP exerts beneficial effects on experimental colitis, which includes protection against bacterial translocation. AP of the tissue-nonspecific isoform is shed in higher amounts to the intestinal lumen in experimental colitis, possibly aiding in intestinal protection.

Effects of flavonoids and other polyphenols on inflammation

Flavonoids are a family of polyphenolic compounds which are widespread in nature (vegetables) and are consumed as part of the human diet in significant amounts. There are other types of polyphenols, including, for example, tannins and resveratrol. Flavonoids and related polyphenolic compounds have significant antiinflammatory activity, among others. This short review summarizes the current knowledge on the effects of flavonoids and related polyphenolic compounds on inflammation, with a focus on structural requirements, the mechanisms involved, and pharmacokinetic considerations. Different molecular (cyclooxygenase, lipoxygenase) and cellular targets (macrophages, lymphocytes, epithelial cells, endothelium) have been identified. In addition, many flavonoids display significant antioxidant/radical scavenging properties. There is substantial structural variation in these compounds, which is bound to have an impact on their biological profile, and specifically on their effects on inflammatory conditions. However, in general terms there is substantial consistency in the effects of these compounds despite considerable structural variations. The mechanisms have been studied mainly in myeloid cells, where the predominant effect is an inhibition of NF-κB signaling and the downregulation of the expression of proinflammatory markers. At present there is a gap in knowledge of in vitro and in vivo effects, although the pharmacokinetics of flavonoids has advanced considerably in the last decade. Many flavonoids have been studied for their intestinal antiinflammatory activity which is only logical, since the gastrointestinal tract is naturally exposed to them. However, their potential therapeutic application in inflammation is not restricted to this organ and extends to other sites and conditions, including arthritis, asthma, encephalomyelitis, and atherosclerosis, among others.

Flavonoids exert distinct modulatory actions on cyclooxygenase 2 and NF-kappaB in an intestinal epithelial cell line (IEC18)

BACKGROUND AND PURPOSE

Cyclooxygenase 2 (COX-2) is involved in inflammatory bowel disease, but the effect of flavonoids at the intestinal epithelial level is unknown. We aimed to characterize the effect and structure-activity relationship of nine selected flavonoids on COX-2 expression in intestinal epithelial cell (IEC)18 cells. We also investigated the signal transduction pathway(s) responsible for the effects observed.

EXPERIMENTAL APPROACH

Intestinal epithelial cell 18, a non-tumour cell line with intestinal epithelial phenotype, was used. COX-2 was measured by Western blot and the involvement of the NF-kappaB pathway assessed by Western blot, pharmacological inhibition, luciferase reporter assays and nuclear translocation experiments.

KEY RESULTS

The effect of flavonoids on COX-2 expression depended on the experimental conditions tested [non-stimulated and lipopolysaccharide (LPS)-stimulated]. Flavonoids caused an increase in COX-2 expression and NF-kappaB-dependent gene transcription under basal conditions. Conversely, under LPS stimulation flavonoids increased, decreased or did not affect COX-2 levels depending on the specific type. Variable effects were observed on extracellular signal regulated kinase/p38/c-Jun N-terminal kinase phosphorylation and p50/65 nuclear translocation.

CONCLUSION AND IMPLICATIONS

The effect of flavonoids on COX-2 expression depended on the balance of the interference with IkappaB-alpha phosphorylation and other signalling targets, and therefore depends on the experimental conditions and on the type of flavonoids. This is expected to result in different effects in inflammatory conditions. In general, flavonoids may limit epithelial COX-2 expression in inflammatory conditions while favouring it when inflammation is not present.

Bovine glycomacropeptide ameliorates experimental rat ileitis by mechanisms involving downregulation of interleukin 17

BACKGROUND AND PURPOSE

Bovine glycomacropeptide (BGMP) is an inexpensive, non-toxic milk peptide with anti-inflammatory effects in rat experimental colitis but its mechanism of action is unclear. It is also unknown whether BGMP can ameliorate inflammation in proximal regions of the intestine. Our aim was therefore two-fold: first, to determine the anti-inflammatory activity of BGMP in the ileum; second, to characterise its mechanism of action.

EXPERIMENTAL APPROACH

We used a model of ileitis induced by trinitrobenzenesulphonic acid in rats. Rats were treated orally with BGMP and its efficacy compared with that of oral 5-aminosalicylic acid or vehicle, starting 2 days before ileitis induction.

KEY RESULTS

BGMP pretreatment (500 mg kg(-1) day(-1)) resulted in marked reduction of inflammatory injury, as assessed by lower extension of necrosis and damage score, myeloperoxidase, alkaline phosphatase, inducible nitric oxide synthase, interleukin 1beta, tumour necrosis factor and interleukin 17. These effects were generally comparable to those of 5-aminosalicylic acid (200 mg kg(-1) day(-1)). Neither compound affected the production of interferon gamma, tumour necrosis factor and interleukin 2 by mesenteric lymph node cells isolated from animals with ileitis. The expression of Foxp3 was increased in ileitis and not reduced significantly by BGMP or aminosalicylate treatment.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that BGMP has anti-inflammatory activity in the ileum with similar efficacy to 5-aminosalicylic acid. The mechanism of action may involve Th17 and regulatory T cells and perhaps macrophages but probably not Th1 lymphocytes. Patients with Crohn's ileitis may benefit from treatment with BGMP.

The bisphosphonate alendronate improves the damage associated with trinitrobenzenesulfonic acid-induced colitis in rats

BACKGROUND AND PURPOSE

The nitrogen-containing bisphosphonates are drugs used successfully in the treatment of osteoporosis. They act inhibiting farnesyl diphosphate synthase. This mechanism may also produce anti-inflammatory effects. The therapeutic activity of alendronate was tested in vivo using a model of inflammatory bowel disease.

EXPERIMENTAL APPROACH

The trinitrobenzenesulfonic acid model of colitis in the rat was used. Rats were treated orally with alendronate and its efficacy compared with that of oral sulphasalazine or vehicle, starting 2 h after colitis induction. The status of the animals was assessed 5 days later.

KEY RESULTS

Alendronate treatment (25 or 75 mg kg(-1) day(-1)) resulted in a decrease in the colonic damage score and loss of body weight (at 25 mg kg(-1) day(-1) only). This was associated to a dramatic reduction in the mRNA levels of interleukin 1 beta (IL-1 beta), monocyte chemoattractant protein 1 (MCP-1) and interleukin 1 receptor antagonist (IL-1 ra). The magnitude of the beneficial effect was comparable to that of sulphasalazine (at a 6-20 fold higher dose). Thus sulphasalazine post-treatment reduced the mRNA levels of IL-1 beta/IL-1 ra and MCP-1 to the same extent as alendronate and additionally lowered colonic alkaline phosphatase activity, but failed to affect body weight loss or colonic damage score. Alendronate failed to exert beneficial effects when administered intraperitoneally.

CONCLUSIONS AND IMPLICATIONS

Oral but not intraperitoneal alendronate significantly protected the colon in experimental rat colitis. Inflammatory bowel disease patients might benefit from exposure to oral alendronate.

Modulation of glucose transporters in rat diaphragm by sodium tungstate

Oral administration of sodium tungstate is an effective treatment for diabetes in animal models. We examined the effects of 6 weeks of oral administration of tungstate on glucose transporters (GLUT) in streptozotocin-induced diabetic rat diaphragm. Diabetes decreased GLUT4 expression while tungstate treatment normalized not only GLUT4 protein but also GLUT4 mRNA in the diabetic rats. Furthermore, treatment increased GLUT4 protein in plasma and internal membranes, suggesting a stimulation of its translocation to the plasma membrane. Tungstate had no effect on healthy animals. There were no differences in the total amount of GLUT1 transporter in any group. We conclude that the normoglycemic effect of tungstate may be partly due to a normalization of the levels and subcellular localization of GLUT4, which should result in an increase in muscle glucose uptake.

Chronic diarrhea impairs intestinal antioxidant defense system in rats at weaning

The aim of the present study was to evaluate the influence of severe protein-energy malnutrition on the antioxidant defense system in the small and large intestine in rats at weaning. Chronic diarrhea and the subsequent malnutrition were induced by oral intake of a lactose-enriched diet. Twenty rats were weaned at 21 days of age, and the control group was fed a semipurified synthetic diet for two weeks. The malnourished group was fed the same diet but carbohydrates were replaced by lactose, and they developed diarrhea one day after. Rats were killed, and macroscopic and histological features were analyzed, DNA content was measured, and alkaline phosphatase, myeloperoxidase, and gamma-glutamyltranspeptidase activities were determined to assess the degree of intestinal injury. Glutathione levels as well as the activities of intestinal glutathione transferase, glutathione reductase, total glutathione peroxidase, selenium-dependent glutathione peroxidase, superoxide dismutase, and catalase were measured to study the antioxidant defense system. Malnourished rats showed loss of body weight and an increase in length and weight in jejunum and ileum, while no significant changes were observed in colon. Epithelial cells showed fewer and shorter microvilli, larger mitochondria with low inner density and loss of cristae, dilated endoplasmic reticulum, and Golgi apparatus. The protein-to-DNA ratio was higher in the jejunum, ileum, and colon of malnourished rats. Glutathione levels decreased 40% in jejunum and 50% in colon of malnourished rats. A 40-50% decrease in the activity of all the enzymes of the antioxidant defense system was observed in the jejunum and ileum of malnourished rats, while only catalase and glutathione transferase activities decreased 50% in colon. These results suggest that early chronic diarrhea and severe protein-energy malnutrition impair the antioxidant defense system in both the small and large intestine, which may have a role in the pathogenesis and maintenance of the vicious circle of malabsorption-diarrhea-malnutrition in infancy.

Experimental ulcerative colitis impairs antioxidant defense system in rat intestine

Increasing attention has been given recently to the role of free radicals in the pathogenesis of ulcerative colitis, since the inflamed intestine is exposed to oxidative stress generated by infiltrating macrophages and neutrophils within the lamina propia. The overall goal of this study was to evaluate whether experimental ulcerative colitis induces significant changes in the antioxidant defense system in an experimental model induced by the intrarectal administration of 2,4,6-trinitrobenzenesulfonic acid. Twenty rats were treated with 80 mg/kg body weight of trinitrobenzenesulfonic acid and 20 with the same volume of 0.9% NaCl. Rats were killed at one and two weeks after treatment to evaluate colon damage by light and electron transmission microscopy. The degree of tissue injury and inflammation was determined by measuring alkaline phosphatase, gamma-glutamyltranspeptidase, and myeloperoxidase activities and prostaglandin E2 and leukotriene B4. Glutathione levels and the activity of the enzymes of the antioxidant defense system were determined. Enzymatic markers of colon injury showed higher activities in rats with ulcerative colitis. Concentrations of prostaglandin E2 and leukotriene B4 were higher in the groups treated for one week with trinitrobenzenesulfonic acid and markers decreased after two weeks of treatment. All antioxidant enzyme activities were higher at one and two weeks after treatment; however, a significant decrease in total glutathione content was also observed. In conclusion, ulcerative colitis induced by trinitrobenzenesulfonic acid damages the intestinal mucosa and is accompanied by a shift in the antioxidant enzyme activities, and low levels of glutathione. This deficiency in glutathione could be a target for new therapies to treat ulcerative colitis.

Dietary trans fatty acids affect docosahexaenoic acid concentrations in plasma and liver but not brain of pregnant and fetal rats

The aim of the present study was to investigate the maternal-fetal transport, incorporation, and effects on liver delta-6 fatty-acid desaturase activity of dietary trans fatty acids in pregnant rats. Three groups of six rats each were fed three experimental diets containing approximately 0%, 15%, and 30% of trans fatty acids but containing the same proportion of linoleic (18:2 n-6) and a-linolenic (18:3 n-3) acids for 10 wk. On d 20 of pregnancy, the animals from each group were killed. We determined the fatty acid profiles in plasma, brain, and liver microsomes of pregnant rats, as well as in placenta and fetal liver and brain. No changes were found in the number of fetuses of the pregnant rats. Trans fatty acids were incorporated in high concentrations in placenta and in maternal and fetal tissues, except brain, strongly elevating the linoleic acid proportion and lowering that of docosahexaenoic acid. The delta-6 fatty-acid desaturase activity in the liver microsomes of the pregnant rats was inhibited by trans isomers. In conclusion, high intakes of trans fatty acids partially inhibit liver delta-6 fatty-acid desaturase in pregnant rats, which may explain, in part, the low concentrations of docosahexaenoic acid in pregnant and fetal tissues. However, the fatty acid composition of both fetal and pregnant rat brain remains mostly unaffected regardless of the dietary trans fatty acid content.

Increased diaphragm expression of GLUT4 in control and streptozotocin-diabetic rats by fish oil-supplemented diets

Dietary fat intake influences plasma glucose concentration through modifying glucose uptake and utilization by adipose and skeletal muscle tissues. In this paper, we studied the effects of a low-fat diet on diaphragm GLUT4 expression and fatty acid composition in control and streptozotocin-induced diabetic rats. Control as well as diabetic rats were divided into three different dietary groups each. Either 5% olive oil, 5% sunflower oil, or 5% fish oil was the only fat supplied by the diet. Feeding these low-fat diets for 5 wk induced major changes in fatty acid composition, both in control and in diabetic rats. Arachidonic acid was higher in diabetic olive and sunflower oil-fed rats with respect to fish oil-fed, opposite to docosahexaenoic acid which was higher in diabetic fish oil-fed rats with respect to the other two groups. Animals receiving a fish oil diet had the lowest plasma glucose concentration. GLUT4 expression in diaphragm, as indicated by GLUT4 protein and mRNA, is modulated both by diabetes and by diet fatty acid composition. Diabetes induced a decrease in expression in all dietary groups. Plasma glucose levels correlated well with the increased amount of GLUT4 protein and mRNA found in fish oil-fed groups. Results are discussed in terms of the influence that arachidonic and n-3 polyunsaturated fatty acids may exert on the transcriptional and translational control of the GLUT4 gene.

Modulation of hepatic and intestinal glutathione S-transferases and other antioxidant enzymes by dietary lipids in streptozotocin diabetic rats

Antioxidant enzymes in liver and small intestine were investigated using control and streptozotocin diabetic rats fed diets with 5% olive, sunflower or fish oil for five weeks. In liver, Glutathione Peroxidase and Superoxide Dismutase decreased and in intestine Glutathione-S-transferase (GST) increased by diabetes. In isolated jejunum and ileum, this increase in GST activity was due to an increase in GST-alpha and -mu isoenzymes in jejunum and GST-alpha, mu and -pi in ileum. Since GST plays an important role in protecting tissues from oxidative damage, our results highlight the role of the intestine against free radicals in physiological or pathological situations.

Sequencing of two alternatively spliced mRNAs corresponding to the extracellular domain of the rat receptor for advanced glycosylation end products (RAGE)

The receptor for advanced glycosylation end products (RAGE) is an integral membrane protein responsible for the recognition and internalization of those extensively modified proteins. The receptor has an extracellular domain that binds to the advanced glycosylation end products. By reverse-transcription and polymerase chain reaction amplification, we have identified in rat liver and kidney two amplified products that correspond to cDNA coding for a part of the extracellular domain of the receptor. Sequencing of these products showed that these amplified molecules were similar except for a 27-bp fragment that was absent in the smaller product. This spliced region is located close to the transmembrane region of the receptor. We have confirmed the possibility of the alternative splicing in the generation of these mRNA isoforms by cloning a fragment of the rat gene for RAGE. This fragment has a distribution of introns and exons fully compatible with the proposed alternative splicing.

Effect of dietary (n-9), (n-6) and (n-3) fatty acids on membrane lipid composition and morphology of rat erythrocytes

Studies focused on the intake of different dietary fats have shown changes in membrane lipid composition and, as a result, alterations in membrane physical properties. These changes affect erythrocyte morphology, receptor activity and oxygen transport, among others. Here, we compare the effects of diets exclusively differing in the type of fat (olive oil rich in monounsaturates, sunflower oil rich in n-6 polyunsaturates and fish oil rich in n-3 polyunsaturates) on fatty acid composition of plasma and erythrocyte membranes and erythrocyte morphology under scanning electron microscopy in rats. Monounsaturates are highest in animals fed olive oil diets; as are linoleic and arachidonic acids in sunflower oil-fed animals and n-3 PUFAs in fish oil-fed animals. The lowest levels of arachidonic acid are found in fish oil-fed animals and so are n-3 PUFAs in sunflower oil-fed animals. Our results show that sunflower oil-fed animals present lower discocyte, the major cell shape related to tissue oxygen supply, and higher codocyte percentages than olive oil- and fish oil-fed groups. Echinocyte percentage is higher in fish oil-fed animals with respect to the other two groups. The collective data indicate that olive oil elevates monounsaturates and the number of discocytes, pointing out a possible beneficial aspect of this dietary fat.

Short-term effects of dietary fats on the lipid composition and desaturase activities of rat liver microsomes

Diets supplemented with 10% coconut, olive or sunflower oil were given to rats at weaning. After two, four and six days, the lipid composition and desaturase activities of liver microsomes were measured. The percentage of oleic acid and delta 9-desaturase activity were increased in animals fed an olive oil diet while animals given sunflower oil showed the highest content of linoleic and polyunsaturated n-6 fatty acids. On day 6, olive oil-fed rats had the highest levels of 22:6 n-3 in the phosphatidylethanolamine fraction. Saturated fatty acids were similar among dietary groups, despite the marked differences in the saturated fatty acid content of the three oils. Polyunsaturated n-6 and n-3 fatty acids decreased during the six days of feeding with coconut oil. Our results show that liver microsome membranes respond to different dietary fatty acids sources by changes in enzyme activities and relative content of some fatty acids after a period of dietary manipulation as brief as 6 days.

Dietary restriction induces biochemical and morphometric changes in the small intestine of nursing piglets

The purpose of this study was to evaluate the biochemical and morphometric changes in the small intestine of nursing piglets caused by 60% dietary restriction, and to ascertain whether this model reproduces the intestinal alterations caused by malnutrition in human infants. Piglets subjected to dietary restriction had significantly lower levels of mucosal DNA and protein, and significantly reduced segmental disaccharidase and leucine aminopeptidase activities compared with age-matched, freely fed controls. However, greater disaccharidase-specific activities were observed in duodenum and jejunum of diet restricted piglets compared with controls. Other findings included significantly lower thickness of the mucose, villous height and width, and villous surface area, a significantly lower number of goblet cells, and significantly greater mucosal crypt depth, intraepithelial leucocyte number, and infiltrated cells per area of lamina propria. The model reproduces most of the biochemical and morphometric changes observed in the small intestine of young human infants with chronic diarrhea and malnutrition, and may be useful in further investigations of the biochemical and molecular mechanisms of intestinal alterations caused by primary malnutrition in early infancy.

Effects of native and hydrolyzed whey protein on intestinal repair of severely starved rats at weaning

The aim of this study was to evaluate the effect of two sources of dietary nitrogen (isolated whey protein and hydrolyzed whey protein) on the intestinal repair of malnourished rats at weaning. The malnutrition was achieved by a 3 days' starvation period. Normally fed male Wistar rats were used as controls. Intestinal repair was studied after a refeeding period of 4 days. The parameters studied included nitrogen balance, lactase, sucrase, isomaltase, and maltase activities of the jejunum; liver acetylcholinesterase and glutamate dehydrogenase activities; and the serum amino acid profile. In addition, tests of intestinal permeability to macromolecules were performed by measurement of ovalbumin and beta-lactoglobulin in serum. Both diets of led to the recovery of the severely starved rats, in terms of the values of all the parameters evaluated. The serum beta-lactoglobulin was the only exception, because its concentration was significantly lower in the normally fed animals. This study suggests that the intestinal mucosal barrier is not completely repaired, even after a 4-day refeeding period, to the point of being suitable to accept an increase in the uptake of antigens.

Age-related response of the small intestine to severe starvation and refeeding in rats

The impact of severe starvation and refeeding on the intestinal mucosa of rats of different ages has been studied in a diet-controlled model. Structural and functional alterations of the small intestinal mucosa were assessed by standard parameters including mucosal protein, DNA content as well as maltase, sucrase and leucine aminopeptidase enzymatic activities. Decreases in mucosal mass, DNA, protein and leucine aminopeptidase activity in both the jejunum and ileum caused by starvation, diminished with age. The depression of disaccharidase activities increased with age in the jejunum but not in the ileum. Except for jejunal protein and leucine aminopeptidase activity, the recovery from starvation, after refeeding, was complete for the other parameters studied, regardless of age.

Newborn universal immunisation against hepatitis B: immunogenicity and reactogenicity of simultaneous administration of diphtheria/tetanus/pertussis (DTP) and oral polio vaccines with hepatitis B vaccine at 0, 2 and 6 months of age

The reactogenicity and immunogenicity of the administration of recombinant vaccine against hepatitis B simultaneously (but at separate sites) with diphtheria/tetanus/pertussis (DTP) and oral polio vaccines were examined. Six hundred and twenty-six children (group I) were given hepatitis B vaccine at 0, 2 and 6 months of age; the other vaccines were administered at 2, 4 and 6 months of age. A control group of 731 children (group II) received only DTP and oral polio vaccines. The results showed that 93% of the infants in group I had anti-HBs titres above the protective level ( > or = 10 mIU ml-1) after vaccination. There were no differences in the immune responses for DTP and polio between the two study groups. The vaccine efficacy against poliomyelitis was 96% for serotype I, 100% for serotype II and 97-98% for serotype III. Of the infants in both groups, 97% had antibodies against B. pertussis; all children were positive for tetanus and diphtheria. There were no differences in the incidences of general reactions between groups. Local swelling and redness were reported following 4.2 and 4.4%, respectively, of all injections of hepatitis B vaccine. These reactions were reported following 31 and 33%, respectively, of all doses of DTP vaccine. It can be concluded that the simultaneous administration of hepatitis B vaccine with the DTP and polio vaccines is well-tolerated; hepatitis B vaccine remained highly immunogenic and did not interfere with the immune response to the other antigens.

Changes in the fatty acid pattern of plasma fractions of rats fed coconut, olive or sunflower oil

The fatty acid composition of plasma phospholipids, triacylglycerols and cholesteryl esters from rats fed diets supplemented (10% w/v) with coconut, olive or sunflower oil during six days has been studied. Rats fed the olive oil diet showed an increased amount of oleic acid whereas the animals fed the sunflower oil diet showed a higher content of linoleic acid than that of the other two groups. n-6 polyunsaturated fatty acids were mainly carried in phospholipid and cholesteryl-ester fractions. There were no differences in the amount of n-6 and n-3 polyunsaturated fatty acids. The effect of diet supplementation was shown after only six days of treatment and the results were similar to those reported in longer treatments.

The short-term effect of dietary fats on the brain fatty acid composition in rats

The effects of dietary fats on brain fatty acid composition were studied in weanling rats. Three groups of rats were fed for six days a basal diet supplemented with a 10% (w/w) of fat as coconut, olive or sunflower oil. There were no differences in the saturated and monounsaturated fatty acid content among the different groups. The more abundant polyunsaturated fatty acids were arachidonic (20:4 n-6) and docosahexaenoic (22:6 n-3) acids. No effect of the diet on their amount in brain membranes has been found. We can conclude that the brain does not modify its fatty acid composition after a short-time administration of these lipids.

Nutritional value and antigenicity of two milk protein hydrolysates in rats and guinea pigs

Two milk protein (whey protein and casein) hydrolysates were obtained by enzymatic hydrolysis. In the casein hydrolysate, an ultrafiltration stage was performed to remove all the peptides with molecular weights > 2500. A nutritional value study of both hydrolysates was undertaken. No differences were found between the native proteins and their enzymatic hydrolysates. Neither the enzymatic hydrolysis nor the heat treatments used affected the nutritional value of the protein sources. The two hydrolysates were studied for antigenic properties. The enzymatic hydrolysis of the whey protein concentrate followed by a thermal treatment at 90 degrees C for 10 min reduced significantly its antigenicity. However, the in vivo allergenicity tests showed some positive reactions in both systemic anaphylaxis and passive cutaneous anaphylaxis. The casein hydrolysate, after being ultrafiltered, was devoid of sensitizing capacity by the oral route and was also ineffective in producing local or systemic anaphylaxis in previously sensitized animals, as shown by in vivo assays.

Effect of dietary nucleotides on the fatty acid composition of rat liver microsomes

The present study was designed to evaluate the influence of dietary nucleotides on the lipid composition of liver microsomes in weanling rats. Rats at weaning were fed, one group with a semipurified nucleotide-free diet and three groups with the same diet supplemented with three different levels of each of the nucleotides AMP, GMP, IMP, UMP and CMP, during 4 weeks. Long chain polyunsaturated fatty acids of the n-6 and n-3 series were increased in phospholipids of liver microsomes for rats fed the nucleotide supplemented diets; however, the cholesterol/phospholipid phosphorus ratio was maintained fairly constant. The results obtained suggest that dietary nucleotides modify the polyunsaturated fatty acid metabolism through a lower rat liver delta-9 desaturase activity and through increased activities of delta-5 and delta-4 desaturases.

[Utilization of an emergency service by patients with HIV infection]

BACKGROUND AND METHODS

To know the impact of HIV infection in a hospital emergency department the health care episodes of seropositive individuals are reviewed in a retrospective study from the January 1 to March 31, 1992. Cases have been identified comparing the list of those infected by HIV with the users of the department during the period studied.

RESULTS

430 episodes in 288 patients (1.5 episodes/patient) have been included constituting 2.3% of the total. 76.4% were males, with a mean age of 29.2 years (range, 18-59) and 60.2% were evaluated the medical area. Hospital admission was indicated on 147 occasions (34.2% versus 19% of seronegatives; p < 0.001). The most frequent diagnoses were infections which were or were not associated to alteration of cellular immunity (32.8%) and complications related with the abuse of opioid substances (23.7%).

CONCLUSIONS

The pathology associated to HIV infection and to the abuse of intravenous drugs constitutes a frequent problem in the emergency departments. The infectious diseases which are or are not associated to alteration in cellular immunity, complications related with the consumption of opioids and the high index of admissions are of note. Professionals carrying out health care work in this medium must be familiarized with the diagnosis and treatment of these processes.

Changes in fatty acid profiles of red blood cell membranes mediated by dietary nucleotides in weanling rats

Dietary nucleotides have been described to play multiple physiological roles. We examined the effect of feeding, for 4 weeks, nucleotide-supplemented diets (N-50 and N-250) on red blood cell (RBC) membrane fatty acid composition in weanling rats. Long-chain polyunsaturated fatty acids (LC-PUFA) of the n-6 series, especially arachidonic acid, increased in total RBC phospholipids in N-50 and N-250 groups. Concentrations of LC-PUFA of the n-3 series were preserved or slightly decreased. Saturates and monoenates also decreased. Phosphatidylethanolamine and sphingomyelin followed the variations observed for total phospholipids. Phosphatidylcholine showed a different response; saturated fatty acids increased while n-6 LC-PUFA decreased. Dietary nucleotides seem to affect the conversion of essential fatty acids to their long-chain derivatives in weanling rats in a similar way to that occurring in newborn infants during early life. These results show that the rat may be a valid model with which to study the biochemical mechanisms by which dietary nucleotides affect fatty acid desaturation.

Changes in lipid composition and desaturase activities of duodenal mucosa induced by dietary fat

In the present work we have studied the effects of feeding either olive or sunflower oil on lipid composition and desaturase activities of duodenal mucosa microsomes. Duodenal microsomes prepared from dogs fed the sunflower oil diet showed higher percentages of saturated, of linoleic and of n - 3 polyunsaturated fatty acids as well as lower levels of oleic, dihomo-gamma-linolenic and arachidonic acids in phosphatidylcholine and phosphatidylethanolamine than those prepared from animals fed the olive oil diet. In sphingomyelin, the dietary supplementation did not produce significant differences between the two groups. The cholesterol/phospholipid molar ratio was higher in the sunflower oil group than in the olive oil group. The in vitro delta 9-desaturase activity was higher in microsomes from the olive oil dogs. The delta 6-desaturase activity was similar in microsomes from the two groups and lower than that found for delta 9-desaturase activity. Desaturase activities were higher in duodenal microsomes than those previously found for liver microsomes.

Effect of long-term feeding olive and sunflower oils on fatty acid composition and desaturation activities of liver microsomes

Changes in microsomal fatty acid composition, delta 9- and delta 6-desaturase activities and cholesterol and phosphorus liver content were studied in dogs fed olive and sunflower oil diets. No changes were observed in the saturated fatty acids between dietary groups. The level of monounsaturated fatty acids was more elevated in animals fed the OO diet, because of its high relative content in this diet although the in vitro delta 9-desaturase activity was similar in microsomes from the two groups. The proportion of arachidonic acid was similar in SO and OO fed animals. This similar level occurred despite a significant increase in the level of linoleic acid in membrane lipids as a result of feeding the SO supplement. The in vitro delta 6-desaturase activity in liver microsomes showed no differences between dogs fed the two diets. Thus, the higher desaturation presented in vivo by microsomes from OO group may be related to the inhibition by linoleic acid of delta 6-desaturase in dogs fed the SO diet. The polyunsaturated fatty acids (PUFA) from the n-3 series were higher in microsomal phosphatidylcholine and phosphatidylethanolamine from animals fed the OO supplemented diet. The cholesterol/phosphorus molar ratio was higher in the SO group in which the unsaturation index was only slightly affected in phospholipids.

Changes in lipid composition of liver microsomes and fatty acyl-CoA desaturase activities induced by medium chain triglyceride feeding

Changes in fatty acid composition, microsomal delta 9- and delta 6-desaturase activities and liver contents of cholesterol and phospholipids were studied in rats fed medium chain triglyceride-supplemented diets. Weanling rats were divided into four groups and fed for three weeks a basal diet with different 10%-fat supplements: corn oil, medium chain triglyceride-corn oil, olive oil and medium chain triglyceride-olive oil. The highest relative content of saturated fatty acids corresponded to corn oil-fed animals. Both monounsaturated fatty acid content and delta 9-desaturase activity were higher in the animals fed olive oil diets than in corn oil-fed rats. The long chain polyunsaturated fatty acids of the n-3 series were increased in the olive oil and medium chain triglyceride-olive oil-fed groups probably due to the lower linoleic/alpha-linolenic ratios found in these two diets. The cholesterol/phospholipid molar ratio was unaffected by diet and the unsaturation index was only slightly changed in the four groups. Thus, some mechanism may be operative under these conditions to maintain the homeostasis of the membrane.

Lipid composition of liver microsomes in rats fed a high monounsaturated fatty acid diet

The fatty acid and cholesterol contents of tissue membranes are the determinants of membrane stability and functionality. This study was designed to evaluate the influence of a high monounsaturated fatty acid diet on the fatty acid composition of rat liver microsomes and on their cholesterol and lipid phosphorus content. Weanling animals were fed for 5 weeks with high fat diets containing olive oil or corn oil. Saturated fatty acids were increased and oleic acid decreased in microsomal total phospholipids and in the three major phosphoglycerides, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI), of rats fed corn oil as compared to the olive oil group. The percentage of linoleic acid was higher in the corn oil group, but only for total phospholipids and PC. Linoleic and alpha-linolenic metabolites were significantly increased in total phospholipids of olive oil-fed animals with respect to those fed corn oil. These changes were responsible for the low unsaturation index found in microsomal phospholipids of the corn oil group. The diet did not affect the microsome cholesterol or the lipid phosphorus content. These results show that, in olive oil-fed rats, the cholesterol content and the degree of unsaturation of liver microsomes was similar to that observed in weanling animals; this probably suggests an adequate maintenance of functionality of membranes in olive oil-fed animals.

[Schönlein-Henoch syndrome: review of a series of 142 cases]

Clinical and laboratory findings in 142 children with Schönlein-Henoch syndrome are studied. The children were diagnosed during a ten-year period (1974-1984). Purpura, as more significant clinical finding, was observed in all patients, followed by articular signs (61.2%), abdominal complaints (57.7%), renal signs (30.2%) and testicular (4.2%). IgA, IgG, IgM, complement and cryoglobulin alterations, are remarkable factors to assume an immunologic origin for the syndrome.

[Nephropathy of the Schöenlein-Henoch syndrome: long-term prognosis in non-selected patients]

Nephritis plays a major role in long-term prognosis of Schönlein-Henoch syndrome. We have studied a group of 142 children with this syndrome; 43 (30.2%) showed clinical evidence of renal disease. Renal biopsy was obtained in 12 cases. A subgroup of 36 patients have been controlled during a much greater two years period. Thirty-five are asymptomatic and one with minor urinary anomalies. Thereafter in our experience the long-term prognosis (means = five years) of Schönlein-Henoch syndrome is excellent in unselected patients.

[Effect of sulfhydryl reagents on mevalonate kinase partially purified from chicken liver]

Unlike other vertebrate mevalonate kinase, the enzyme partially purified from neonatal chick liver was not activated by the -SH group protectors reduced glutathione, cysteine, dithiothreitol and beta-mercaptoethanol at any concentrations assayed (0.01-10.00 mM). However, the activity was found to be sensitive to thiol group binding reagents. p-Hydroxymercuribenzoate was the most active inhibitor. At 0.1 mM concentration, p-HMB completely abolished the enzyme activity. N-ethylmaleimide (0.01-1.00 mM) was practically ineffective. Inhibition by p-HMB was temperature dependent, being more potent at 37 degrees C than at 4 degrees C.

Partial purification and properties of mevalonate kinase from neonatal chick liver

Mevalonate kinase from neonatal chick liver has been partially purified by ammonium sulphate precipitation and Sephadex G100 and DEAE-cellulose fractionation. The kinetic characteristics agreed with the sequential mechanism suggested for the enzyme and provided apparent Km values of 0.01 mM for mevalonic acid and 0.25 mM for ATP. Partially purified mevalonate kinase from neonatal chick liver showed an absolute specificity for ATP. Mn2+ was a better activator than Mg2+ at low concentrations (0.1-1.0 mM). Higher Mn2+ concentrations produced a clear inhibition of mevalonate kinase. Likewise, addition of EDTA, with or without metal ions, clearly inhibited the enzymatic reaction.

Properties of mevalonate-activating enzymes in developing chick brain

Phosphorylation of mevalonic acid has been studied in 1-3 day chicks. Addition of Mg2+ or Mn2+ strongly increased the formation of phosphorylated derivatives. Mevalonate phosphorylation showed an absolute nucleotide requirement, being ATP and ITP the most effective phosphate donors. Unlike other vertebrate mevalonate kinases, the enzyme from chick brain did not require thiol group protectors as activators. However, the enzyme was found to be sensitive to thiol binding reagents.