Propionyl-L-carnitine as protector against adriamycin-induced cardiomyopathy

Propionyl- l -carnitine (PLC) is a naturally occurring compound that has been considered for the treatment of many forms of cardiomyopathies. In this study, the possible mechanisms whereby PLC could protect against adriamycin (ADR)-induced cardiomyopathy were carried out. Administration of ADR (3 mg kg(-1)i.p., every other day over a period of 2 weeks) resulted in a significant two-fold increase in serum levels of creatine phosphokinase, lactate dehydrogenase and glutamic oxaloacetic transaminase, whereas daily administration of PLC (250 mg kg(-1), i.p. for 2 weeks) induced non-significant change. Daily administration of PLC to ADR-treated rats resulted in complete reversal of ADR-induced increase in cardiac enzymes except lactate dehydrogenase which was only reversed by 66%. In cardiac tissue homogenate, ADR caused a significant 53% increase in malonedialdehyde (MDA) and a significant 50% decrease in reduced glutathione (GSH) levels, whereas PLC induced a significant 33% decrease in MDA and a significant 41% increase in GSH levels. Daily administration of PLC to ADR-treated rats completely reversed the increase in MDA and the decrease in GSH induced by ADR to the normal levels. In rat heart mitochondria isolated 24 h after the last dose, ADR induced a significant 48% and 42% decrease in(14)CO(2)released from the oxidation of [1-(14)C]palmitoyl-CoA and [1-(14)C]palmitoylcarnitine, respectively, whereas PLC resulted in a significant 66% and 54% increase in the oxidation of both substrates, respectively. Interestingly, administration of PLC to ADR-treated rats resulted in complete recovery of the ADR-induced decrease in the oxidation of both substrates. In addition, in rat heart mitochondria, the oxidation of [1-(14)C]pyruvate, [1-(14)C]pyruvate and [1-(14)C]octanoate were not affected by ADR and/or PLC treatment. Moreover, ADR caused severe histopathological lesions manifested as toxic myocarditis which is protected by PLC. Worth mentioning is that PLC had no effect on the antitumour activity of ADR in solid Ehrlich carcinoma. Results from this study suggest that: (1) in the heart, PLC therapy completely protects against ADR-induced inhibition of mitochondrial beta -oxidation of long-chain fatty acids; (2) PLC has and/or induces a powerful antioxidant defense mechanism against ADR-induced lipid peroxidation of cardiac membranes; and finally (3) PLC has no effect on the antitumour activity of ADR.

Latent coeliac disease in a child with epilepsy, cerebral calcifications, drug-induced systemic lupus erythematosus and intestinal folic acid malabsorption associated with impairment of folic acid transport across the blood-brain barrier

A 15-year-old boy with epilepsy and cerebral calcifications, treated with valproic acid, ethyl phenylbarbiturate and ethosuximide, was referred for drug induced systemic lupus erythematosus. Anti-gliadin (AGA) and anti-endomysium (EMA) antibody tests were both positive (EMA titre 1:50). Endoscopic duodenal biopsy showed intense chronic inflammation without villous atrophy or crypt hyperplasia. The child was discharged with a gluten-containing diet. The follow-up showed an increase in EMA titre (1:200) and the persistence of AGA. After 15 months, a second endoscopic intestinal biopsy showed flat mucosa and villous atrophy. Three serum folic acid determinations showed 1.8, 2.4, 2.0 ng/ml (reference range 2.5-16.9 ng/ml) prior to the two intestinal biopsies, but returned to normal levels (11.8 ng/ml) after a gluten-free diet and oral supplementation together. Two years later, the frequency of epileptic seizures was unchanged despite ongoing anti-epileptic treatment and a gluten-free diet. As cerebral calcification and epilepsy are reminiscent of the findings in congenital folate malabsorption, oral loading tests with 5 mg folic acid were carried out and showed impaired intestinal absorption and a defect in the transport across the blood-brain barrier. Low CSF folate levels (13.9 and 12.6 ng/ml, reference range 15-40 ng/ml) and an alteration in the CSF/serum folate ratio (1.43 and 1.16, normal ratio 3:1) were also found as well as increased levels of cystathionine both in CSF (40 micromol/l, reference range 18-28 micromol/l) and in serum (32 micromol/l, reference value <0.10 micromol/l).

CONCLUSION

Impairment of intestinal folic acid absorption with a defect in folic acid transport across the blood-brain barrier has been demonstrated in a case of epilepsy and cerebral calcifications associated with coeliac disease.

Effects of acetyl-L-carnitine on the formation of fatty acid ethyl esters in brain and peripheral organs after short-term ethanol administration in rat

Increasing evidence suggests that Fatty acid ethyl esters (FAEE) play a central role in ethanol induced organ damage. In the current study we measured FAEE formation in rats after short-term oral administration of ethanol, in the presence and absence of pre-treatment with acetyl-L-carnitine. Ethanol treatment caused a significant increase in the levels of FAEE, particularly in the brain and heart, but also in the kidney and liver. Increases in FAEE were associated with a significant increase in FAEE synthase activity, GSH transferase activity, and lipid hydroperoxide levels. Pretreatment with acetyl-L-carnitine resulted in a significant reduction of FAEE accumulation, decrease in FAEE synthase and GSH transferase activities, and lipid hydroperoxide levels. Administration of acetyl-L-carnitine greatly reduced the metabolic abnormalities due to non-oxidative ethanol metabolism, through an increment in lipid metabolism/turnover and by the modulation of the activities of enzymes associated with FAEE synthesis. These results suggest a potentially important pharmacological role for acetyl-L-carnitine in the prevention of alcohol-induced cellular damage.

[Reye's syndrome: the death of a syndrome? (Or death by a syndrome?)]

Reye syndrome is characterized by acute encephalopathy and fatty degeneration of the liver almost exclusively in children. The onset is heralded by profuse vomiting and varying neurologic impairment from irritability to coma, decerebration and death. The encephalopathy must be associated with a greater increase in the levels of ammonia, or alanine amino-transferase and aspartate amino-transferase in serum; and with a fatty metamorphosis of the liver diagnosed by biopsy or at autopsy. The only characteristic universally accepted as diagnostic are the specific mithocondrial changes in the liver-biopsy specimen. Larger studies confirmed the association of aspirin with RS. The CDC of Atlanta cautioned physician and parents and a dramatic decline in case began at that time. Classic Reye syndrome is now so rare in the USA that when an apparent case is encountered in a child who has not taken aspirin, other diagnoses should be considered. After a brief survey of RS relative lack of specificity of case definition and of the polyhedric etiopathogenetic moments, the A. on the personal experience, point: a) the biological unicity of the man and the necessary coexistence of "constitutional" factors (metabolic and/or endocrine, and/or immunitary factors, the later almost never investigated), toxic, and infectious factors for the syndrome's deflagration; b) some aspects of the continued existence of therapeutic and diagnostic problems: the aspirin and/or salicilate use and the pharmacogenetic; the continued existence of other, generally similar conditions, such the drug and other known and unknown toxic mithocondrial factors that provoke this unusual response to common infections; and the inborn errors of metabolism; c) some practical aspects of diagnostic and therapeutic approach.

A 1-year controlled trial of acetyl-l-carnitine in early-onset AD

OBJECTIVE

To determine the efficacy of acetyl-l-carnitine (ALCAR) on the rate of decline in early-onset AD patients.

METHODS

A 1-year, multicenter, double-blind, placebo-controlled, randomized trial was conducted. Subjects were 45 to 65 years old, with a diagnosis of probable AD according to National Institute of Neurological Communicative Disorders-Alzheimer's Disease and Related Disorders Association criteria and had a Mini-Mental State Examination (MMSE) score between 12 and 26. They were treated with ALCAR (1 g tid) or placebo. Primary outcome measures were the Alzheimer's Disease Assessment Scale-Cognitive Component and the Clinical Dementia Rating Scale. Secondary measures included the ADAS Non-Cognitive Subscale, the MMSE, an Activities of Daily Living Scale (ADL), and a Clinician-Based Impression of Change (CIBIC).

RESULTS

Two-hundred twenty-nine patients were enrolled and randomized to drug treatment, with 117 taking placebo and 112 taking ALCAR. There were no significant differences between the two groups at baseline. For the primary outcome measures, there were no significant differences between the treatment groups on the change from baseline to endpoint in the intent-to-treat analysis. In the completer sample only, there was less deterioration in the MMSE for the ALCAR-treated subjects. There was no difference in rate of decline on the CIBIC and the ADL scale. There were no significant differences in the incidence of adverse events by treatment arm.

CONCLUSION

Overall, in a prospectively performed study in young-onset AD patients, ALCAR failed to slow decline. Less decline was seen on the MMSE in the completer sample only, with the difference being mediated by reducing decline in attention. A combination of ALCAR and a cholinesterase inhibitor should be tested for additivity.

Carnitine: an osmolyte that plays a metabolic role

Carnitine, gamma-trimethyl-beta-hydroxybutyrobetaine, is a small molecule widely present in all cells from prokaryotic to eukaryotic ones. It is the sole source of carbon and nitrogen in some bacteria; it serves as osmoprotectant in others. It is a carrier of acyl moieties, and exclusively of long-chain fatty acids for mitochondrial beta-oxidation in mammals. The conspicuously similar composition of the intracellular milieu among widely different species in relation to organic osmolyte systems involves the methylamine family to which carnitine belongs. This prompted us to examine the osmolytic properties of carnitine in an attempt to clarify the metabolic functions carnitine has acquired during evolution. An understanding of the metabolic functions of this organic compatible solute impinge on research involving this compound.

Effect of acetyl-L-carnitine on ethanol consumption and alcohol abstinence syndrome in rats

The effect of acetyl-L-carnitine on alcohol consumption and its possible ability to alleviate all symptomatology of ethanol withdrawal syndrome has been investigated in rats. Alcohol-dependence was induced in animals (9-15 g/kg ethanol solution at 20% for a period of 4 days) in order to measure the effects of acetyl-L-carnitine on ethanol abstinence syndrome. The ethanol dependence phase was characterized by the onset of signs and responses of progressive severity: hyperactivity, tremors, spastic rigidity and spontaneous convulsive seizures. After 4 days, 8 h after the last ethanol administration, two groups of animals received acetyl-L-carnitine (125 mg/kg and 250 mg/kg intraperitoneally, respectively) and the intensity of the withdrawal syndrome was assessed on the basis of the appearance of tremors. The effect of acetyl-L-carnitine on voluntary alcohol consumption was investigated in a rat line selected for innate ethanol preference. For 15 days the animals could freely choose both water and/or a hydroalcoholic solution (10% p:v). Acetyl-L-carnitine was given intraperitoneally at a dose of 200 mg/kg twice daily. The water and the hydroalcoholic solution levels were checked at the same time daily. Acetyl-L-carnitine treatment significantly reduced the onset of tremors in ethanol withdrawal syndrome as well as the level of ethanol intake in alcohol-preferring rats. These results suggest a possible pharmacological role of acetyl-L-carnitine in the treatment of alcohol dependence.

Regulation by carnitine of myocardial fatty acid and carbohydrate metabolism under normal and pathological conditions

This review focuses on the regulation of myocardial fatty acids and glucose metabolism in physiological and pathological conditions, and the role of L-carnitine and of its derivative, propionyl-L-carnitine. Fatty acids are the major oxidation fuel for the heart, while glucose and lactate provide the remaining need. Fatty acids in cytoplasm are transformed to long-chain acyl-CoA and transferred into the mitochondrial matrix by the action of three carnitine dependent enzymes to produce acetyl-CoA through the beta-oxidation pathway. Another source of mitochondrial acetyl-CoA is from the oxidation of carbohydrates. The pyruvate dehydrogenase (PDH) complex, the key irreversible rate limiting step in carbohydrate oxidation, is modulated by the intra-mitochondrial ratio acetyl-CoA/CoA. An increased ratio results in the inhibition of PDH activity. A decreased ratio can relieve the inhibition of PDH as shown by the transfer of acetyl groups from acetyl-CoA to carnitine, forming acetylcarnitine, a reaction catalyzed by carnitine acetyl-transferase. This activity of L-carnitine in the modulation of the intramitochondrial acetyl-CoA/CoA ratio affects glucose oxidation. Myocardial substrate metabolism during ischemia is dependent upon the severity of ischemia. A very severe reduction of blood flow causes a decrease of substrate flux through PDH. When perfusion is only partially reduced there is an increase in the rate of glycolysis and a switch from lactate uptake to lactate production. Tissue levels of acyl-CoA and long-chain acylcarnitine increase with important functional consequences on cell membranes. During reperfusion fatty acid oxidation quickly recovers as the prevailing source of energy, while pyruvate oxidation is inhibited. A considerable body of experimental evidence suggests that L-carnitine exert a protective effect in in vitro and in vivo models of heart ischemia and hypertrophy. Clinical trials confirm these beneficial effects although controversial results are observed. The actions of L-carnitine and propionyl-L-carnitine cannot be explained as exclusively dependent on the stimulation of fatty acid oxidation but rather on a marked increase in glucose oxidation, via a relief of PDH inhibition caused by the elevated acetyl-CoA/CoA ratio. Enhanced pyruvate flux through PDH is beneficial for the cardiac cells since less pyruvate is converted to lactate, a metabolic step resulting in the acidification of the intracellular compartment. In addition, L-carnitine decreases tissue levels of acyl moieties, a mechanism particularly important in the ischemic phase.

Cancer and anticancer therapy-induced modifications on metabolism mediated by carnitine system

An efficient regulation of fuel metabolism in response to internal and environmental stimuli is a vital task that requires an intact carnitine system. The carnitine system, comprehensive of carnitine, its derivatives, and proteins involved in its transformation and transport, is indispensable for glucose and lipid metabolism in cells. Two major functions have been identified for the carnitine system: (1) to facilitate entry of long-chain fatty acids into mitochondria for their utilization in energy-generating processes; (2) to facilitate removal from mitochondria of short-chain and medium-chain fatty acids that accumulate as a result of normal and abnormal metabolism. In cancer patients, abnormalities of tumor tissue as well as nontumor tissue metabolism have been observed. Such abnormalities are supposed to contribute to deterioration of clinical status of patients, or might induce cancerogenesis by themselves. The carnitine system appears abnormally expressed both in tumor tissue, in such a way as to greatly reduce fatty acid beta-oxidation, and in nontumor tissue. In this view, the study of the carnitine system represents a tool to understand the molecular basis underlying the metabolism in normal and cancer cells. Some important anticancer drugs contribute to dysfunction of the carnitine system in nontumor tissues, which is reversed by carnitine treatment, without affecting anticancer therapeutic efficacy. In conclusion, a more complex approach to mechanisms that underlie tumor growth, which takes into account the altered metabolic pathways in cancer disease, could represent a challenge for the future of cancer research.

Attenuation by acetyl-L-carnitine of neurological damage and biochemical derangement following brain ischemia and reperfusion

Alterations in brain metabolism after ischemia and reperfusion are described herein. Several roles played by carnitine and acetylcarnitine can be of particular relevance in counteracting these brain metabolism alterations. The effects of acetylcarnitine in several experimental models of brain ischemia in rats are described. The data obtained show that acetylcarnitine can have significant clinical neuroprotective effects when administered shortly after the onset of focal or global cerebral ischemia. In the canine cardiac arrest model, acetylcarnitine improved the postischemic neurological outcome and tissue levels of lactate and pyruvate were normalized. A trend toward reversal of pyruvate dehydrogenase inhibition in acetylcarnitine-treated dogs was also observed. The immediate postischemic administration of acetylcarnitine prevents free radical-mediated protein oxidation in the frontal cortex of dogs submitted to cardiac arrest and resuscitation. The transfer of the acetyl group to coenzyme A (CoA) to form acetyl-CoA as the primary source of energy is a plausible mechanism of action of acetylcarnitine.

Carnitine increases glucose disposal in humans

OBJECTIVE

The goal of this work is to assess the effect of L-carnitine on glucose disposal, particularly on insulin sensitivity, in healthy volunteers.

METHODS

Fourteen healthy human volunteers were subjected to the intravenous glucose tolerance test (analyzed by means of the minimal model technique), together with indirect calorimetry and measurement of serum free fatty acids, after a bolus of glucose plus carnitine (C) or a bolus of glucose plus saline (P).

RESULTS

The minimal model demonstrated a significant increase in glucose disposal from plasma with carnitine: Glucose effectiveness passed from 2.7%/min to 3.8%/min. No significant changes were observed in the Insulin Sensitivity Index or in Insulin/C-Peptide secretion. Calorimetry showed a significant increase in respiratory quotient, resulting from a significant increase in carbohydrate oxidation rate during carnitine administration by an average of 0.0176+/-0.0118 g/min (p=0.015). Energy expenditure was not modified by treatment. A smaller decrease in plasma fatty acid concentrations was noted with carnitine plus glucose than after glucose alone.

CONCLUSIONS

From these data it appears that carnitine stimulates glucose disposal and oxidation in the healthy volunteer. Therefore, carnitine might be useful as an adjunct in the therapy of diabetes mellitus.

Role of acetyl-L-carnitine in rat brain lipogenesis: implications for polyunsaturated fatty acid biosynthesis

This study was undertaken to explore the metabolic fate of acetyl-L-carnitine in rat brain. To measure the flux of carbon atoms into anabolic processes occurring at regional levels, we have injected [1-(14)C]acetyl-L-carnitine into the lateral brain ventricle of conscious rats. After injection of [1-(14)C]acetyl-L-carnitine, the majority of radioactivity was recovered as 14CO2 expired (60% of that injected). The percentage of radioactivity recovered in brain was 1.95, 1.60, 1.30, and 0.93% at 1, 3, 6, and 22 h, respectively. Radioactivity distribution in various lipid components indicated that the fatty acid moiety of phospholipid contained the majority of radioactivity. The radioactive profile of these fatty acids showed that the acetyl moiety of acetyl-L-carnitine was incorporated into saturated (60%), monounsaturated (15%), and polyunsaturated (25%) fatty acids [mainly present in 20:4 (5.2%) and 22:6 (7.8%)]. Injection in the brain ventricle of radioactive glucose, the major source of acetyl-CoA in the CNS, revealed that glucose was a precursor of saturated (85%) and monounsaturated (15%) but not of polyunsaturated fatty acids. Thus, this study demonstrated distinct fates of glucose and acetyl-L-carnitine following intracerebroventricular injection. In summary, these data implicate acetyl-L-carnitine as an important member of a complex acetate trafficking system in brain lipid metabolism.

L-carnitine esters as "soft", broad-spectrum antimicrobial amphiphiles

A new class of antimicrobial, "soft", quaternary ammonium l-carnitine esters, of the type (CH3)3N+-CH2-CHOCO(R1)-CH2-COO(R2) Cl-, has been designed, with R1 and R2 being in general long-chain alkyl substituents. The series shows good activity against a wide range of bacteria, yeasts, and fungi. Lipophilicity has been measured by RP-HPLC method to give the logarithm of the experimental capacity factor (log k'), and a quantitative relationship has been determined between log k' and the theoretical partition coefficient (CLOGP); also, bond-dipole descriptors have been introduced into calculations by accounting for polar moieties present within the apolar cores of the molecules, giving a more refined calculated capacity factor (log k'calcd). Finally the latter has been related to the antimicrobial activity (MIC values). The proposed models are predictive for the best broad-spectrum antimicrobial compound within the series.

Tissue transglutaminase-catalyzed formation of high-molecular-weight aggregates in vitro is favored with long polyglutamine domains: a possible mechanism contributing to CAG-triplet diseases

To investigate possible biochemical mechanisms underlying the "toxic gain of function" associated with polyglutamine expansions, the ability of guinea pig liver tissue transglutaminase to catalyze covalent attachments of various polyamines to polyglutamine peptides was examined. Of the polyamines tested, spermine is the most active substrate, followed by spermidine and putrescine. Formation of covalent cross links between polyglutamine peptides and polyamines yields high-M(r) aggregates--a process that is favored with longer polyglutamines. In the presence of tissue transglutaminase, purified glyceraldehyde-3-phosphate dehydrogenase (a key glycolytic enzyme that binds tightly to the polyglutamine domains of both huntingtin and dentatorubral-pallidoluysian atrophy proteins) is covalently attached to polyglutamine peptides in vitro, resulting in the formation of high-M(r) aggregates. In addition, endogenous glyceraldehyde-3-phosphate dehydrogenase of a Balb-c 3T3 fibroblast cell line overexpressing human tissue transglutaminase forms cross-links with a Q60 polypeptide added to the cell homogenate. Possibly, expansion of polyglutamine domains (thus far known to occur in the gene products associated with at least seven neurodegenerative diseases) leads to increased/aberrant tissue transglutaminase-catalyzed cross-linking reactions with both polyamines and susceptible proteins, such as glyceraldehyde-3-phosphate dehydrogenase. Formation of cross-linked heteropolymers may lead to deposition of high-M(r) protein aggregates, thereby contributing to cell death.

Anaphylaxis to sheep's milk cheese in a child unaffected by cow's milk protein allergy

A 5-year-old atopic boy unaffected by cow's milk protein allergy experienced several anaphylactic reactions after eating food containing "pecorino" cheese made from sheep's milk. Prick-prick tests were strongly positive to sheep's buttermilk curd and 'pecorino' sheep's cheese. Skin prick tests to fresh sheep's milk and to goat's milk were also positive, whereas they were negative to all cow's milk proteins, to whole pasteurized cow's milk and to cheese made from cow's milk. Specific IgE antibodies were negative to all cow's milk proteins.

CONCLUSION

Sheep's milk and cheese derived from sheep's milk may cause severe allergic reactions in children affected and, as we report, in children not affected by cow's milk protein allergy.

The entry of [1-13C]glucose into biochemical pathways reveals a complex compartmentation and metabolite trafficking between glia and neurons: a study by 13C-NMR spectroscopy

Glial-neuronal interactions were investigated in rats injected intraperitoneally with [1-13C]glucose and killed after 15, 30, 45, or 60 min. Brain extracts were analyzed by 13C-NMR spectroscopy and the fractional 13C-enrichment at individual carbon positions was measured for amino acids, lactate, and N-acetyl-aspartate. [1-13C]Glucose was shown to be metabolized by both neurons and glia, with the anaplerotic pathway through pyruvate carboxylase (PC) accounting for 10% of total cerebral glucose metabolism. The PC-mediated pathway accounted for 39% of the glutamine synthesis, and for 8, 6, 14% of glutamate, GABA, and aspartate synthesis, respectively. These results reflect a compartmentation of the cerebral amino acids synthesis within glial and neuronal cells. The appearance of the 13C-label in C5 of glutamate and glutamine, C1 of GABA and C2 of lactate, is suggestive of pyruvate, formation from TCA cycle intermediates and provides evidence of metabolite trafficking between astrocytes and neurons.

Acetyl-L-carnitine flux to lipids in cells estimated using isotopomer spectral analysis

Acetyl-L-carnitine is known as a reservoir of activated acetyl units and as a modulator of metabolic function. The objective of this study was to quantify the fate of the acetyl moiety of acetyl-L-carnitine in lipogenic pathways. Lipogenesis was studied in an adipocyte model, differentiated 3T3-L1 cells, and a hepatoma cell, HepG2 cells. Lipogenesis and ketogenesis were examined in rat hepatocytes. Both de novo synthesis and elongation of fatty acids were investigated using gas chromatography/mass spectrometry and [1,2-(13)C]acetyl-L-carnitine. Comparisons were performed with [13C]glucose and [13C]acetate. Isotopomer Spectral Analysis, a stable isotope method for differentiating between the enrichment of the precursor and the amount of synthesis was used to analyze the data. Acetyl-L-carnitine was generally less effective than acetate as a precursor for de novo lipogenesis. The effects of acetyl-L-carnitine were not identical to those of acetate plus carnitine as expected if acetyl-L-carnitine flux to acetyl CoA is controlled by carnitine acetyl transferase. Acetyl-L-carnitine (2 mM) contributed approximately 10% of the lipogenic acetyl-CoA used for synthesis and elongation as well as 6% of the ketogenic acetyl-CoA. No differences were found between the precursor enrichment for de novo lipogenesis and for elongation of saturated fatty acids. Flux of acetyl-L-carnitine to lipid was increased, not decreased, by the ATP citrate lyase inhibitor, -hydroxycitrate. In contrast, flux of glucose to lipid was dramatically decreased by this inhibitor. These results indicate that flux of acetyl-L-carnitine to lipid can bypass citrate and utilize cytosolic acetyl-CoA synthesis.

Correlation between Epstein Barr virus antibodies, serum IgE and atopic disease

It is currently accepted that viral infections may influence the development of atopy. In the present study we evaluated serum IgE levels as well as the prevalence of symptoms indicative of atopic disease and EBV antibodies in 353 children aged from 1 month to 19 years. Antibodies against EBV were detected by immunofluorescence. IgE levels in serum were measured by enzyme immunoassay. Dividing the study population according to EBV seropositivity and age, we noted that the prevalence of high IgE levels (> 2 s.d.) was, in total, more frequent in the EBV negative (32.9%) than in the positive subjects (27.6%). Interestingly, this higher prevalence was found only in the groups aged under six, especially in the 7 to 29 month group, where it was statistically significant (p=0.037), whereas in the 6-19 year group the situation was reversed. Furthermore, selecting only the atopic children younger than 3 years of age with high IgE levels and clinical symptoms of atopy (wheezing and/or dermatitis) it was possible to demonstrate lower EBV seropositivity compared with the normal IgE controls for each group, even though these differences were not statistically significant. In conclusion, the results of our study suggest that, in our selected population, EBV infection in the first years of life is associated with a lower prevalence of high IgE levels.

Acetyl-L-carnitine arginine amide prevents beta 25-35-induced neurotoxicity in cerebellar granule cells

Cerebellar granule cells (CGC) at different stages of maturation in vitro (1 or 6 DIV), were treated with beta 25-35 and acetyl-L-carnitine arginine amide (ST857) in presence of 25 mM KCl in the culture medium, and neuronal viability was assessed. Three days of treatment slightly modified the survival of 1 DIV-treated cells, which degenerate and die five days later beta-amyloid matching. Similarly, a significative neurotoxic effect was observed on 6 DIV treated-cells after 5 days of exposure to the peptide, while the death occurred within 8 days. ST857 coincubated with beta 25-35 was able to rescue neurons from beta 25-35-induced neurotoxicity. We also studied the changes in Ca2+ homeostasis following glutamate stimulation, in control and beta-amyloid treated single cells, either in presence or in absence of ST857. beta 25-35 did not affect basal [Ca2+]i, while modified glutamate-induced [Ca2+]i increase, causing a sustained plateau phase of [Ca2+]i, that persisted after the removal of the agonist. ST857 pretreatment completely reverted this effect suggesting that, in CGC chronically treated with beta 25-35, ST857 could protect the cells by neurotoxic insults of the peptide likely interfering with the cellular mechanisms involved in the control of Ca2+ homeostasis.

In experimental diabetes the decrease in the eye of lens carnitine levels is an early important and selective event

Carnitine is present in the eye tissues of the rabbit and the highest concentration is found in the lens. In streptozotocin-diabetic rats, the carnitine loss of the lens is an initial and important event. At 8 days after the induction of diabetes, the carnitine content in the rat lens was reduced by 63% compared to control. The loss of lens carnitine continued at 15 and 45 days after the induction. Total carnitine level in the serum was diminished by 15 days, and the reduction in percentage term was much lower in comparison to the loss of lens carnitine. In the rabbit after alloxan-diabetes induction, there is an extensive loss of carnitine in the lens: -85% after 4 months. The carnitine levels in the other eye tissues seem substantially unaffected. The loss of lens carnitine was present even with an inconsistent hyperglycaemia. No difference was found in serum carnitine levels between controls and alloxan-treated rabbits. The role of carnitine in lens is still unclear, but its loss may be related to the appearance of cataract. A derivative of carnitine, acetylcarnitine, might prevent the processes involved in the formation of cataracts by a pharmacological action, as has been shown for aspirin.