Intravenous injection of l-aspartic acid ß-hydroxamate attenuates choroidal neovascularization via anti-VEGF and anti-inflammation.

Choroidal neovascularization (CNV) is a hallmark of exudative age-related macular degeneration (exAMD) and a major cause of visual loss in AMD. Despite the widespread use of anti-VEGF therapy, serious adverse effects arise from repeated intravitreal injection of anti-VEGF antibodies, which warrant alternative strategy. We report herein that in a CNV murine model created by krypton red laser, intravenous injection of a serine racemase inhibitor, l-Aspartic acid ß-hydroxamate (L-ABH), significantly reduced CNV at the dose 6 mg/kg on the first day before and followed by 3 mg/kg on the third day after laser injury. The CNV volumes were analyzed with isolectin GS-IB4 staining on choroidal/RPE flat mounts on the seventh day after laser injury. Injection of L-ABH did not produce negative effects on retinal function and visual behavior. To dissect the mechanism in vitro, pretreatment with L-ABH in primary RPE cultures significantly reduced production of vascular endothelial growth factor (VEGF) and macrophage chemotactic protein 1 (MCP-1) by TNFα-primed RPEs. Consistent with these observations, L-ABH pretreatment significantly attenuated macrophage migration mediated by TNFα-primed RPE. Collectively, intravenous injection of L-ABH significantly reduced CNV volumes via reducing production of VEGF and MCP-1 by inflammation-primed RPEs.

Asparagine preserves intestinal barrier function from LPS-induced injury and regulates CRF/CRFR signaling pathway.

Stress causes intestinal inflammation and barrier dysfunction. Corticotrophin-releasing factor (CRF)/CRF receptor (CRFR) signaling pathway has been shown to be important for stress-induced intestinal mucosal alteration. L-Asparagine (ASN) is a powerful stimulator of ornithine decarboxylase and cell proliferation in a variety of cell types, including colonic cells. In the present study, we investigated whether dietary ASN supplementation could alleviate the damage of intestinal barrier function caused by LPS through modulation of CRF/CRFR signaling pathway. Twenty-four weaned pigs were randomly divided into one of four treatments: (1) non-challenged control; (2) Escherichia coli LPS challenged control; (3) LPS + 0.5% ASN; (4) LPS + 1.0% ASN. LPS stress induced villous atrophy, intestinal morphology disruption and decreased claudin-1 expression. ASN supplementation increased intestinal claudin-1 protein expression and alleviated villous atrophy and intestinal morphology impairment caused by LPS stress. In addition, ASN supplementation increased the number of intestinal intraepithelial lymphocytes and reversed the elevations of intestinal mast cell number and neutrophil number induced by LPS stress. Moreover, ASN decreased the mRNA expression of intestinal CRF, glucocorticoid receptors and tryptase. These results indicate that ASN attenuates intestinal barrier dysfunction induced by LPS stress, and regulates CRF/CRFR1 signaling pathway and mast cell activation.

Asn194Lys mutation in RVG29 peptide increases GFP transgene delivery by endocytosis to neuroblastoma and astrocyte cells.

OBJECTIVES: A cell-penetrating peptide-based delivery system could target specific types of cells for therapeutic genes delivery. To increase the gene delivery efficiency into neuronal phenotype cells, we introduced an Asn194Lys mutation to RVG29 peptide derived from rabies virus glycoprotein and added a nuclear localization signal to enhance its nuclear import. METHODS: Mutant RVG or wild-type RVG peptide, a karyophilic peptide (KP) and a plasmid encoding green fluorescent protein (pGL) were bound by electrostatic charges to form four different kinds of RVG complexes. Immunofluorescence was used to assess the gene transfection efficiency into astrocytes, oligodendrocyte precursor cells (OPCs), SH-SY5Y, HeLa and NIH/3T3 cells. The cellular uptake mechanism of RVG29 complexes was examined using endocytosis inhibitors. KEY FINDINGS: The mRVG29 peptide has the ability to enhance the nuclear import of plasmids. The Asn194Lys mutation in RVG29 peptide of the pGL-mRVG29 complex and the addition of KP to the pGL-RVG29-KP complex increased the capacity to deliver DNA by endocytosis in astrocytes and SH-SY5Y cells. CONCLUSIONS: The complexes pGL-mRVG29 and pGL-RVG29-KP have specificity for transfecting astrocytes and SH-SY5Y cells. The karyophilic capacity of this new mRVG peptide render it promising candidate to act as gene delivery vector into the brain cells.

Synergistic Cytotoxic Effect of L-Asparaginase Combined with Decitabine as a Demethylating Agent in Pediatric T-ALL, with Specific Epigenetic Signature.

T-Acute Lymphoblastic Leukemia (T-ALL) remains a subgroup of pediatric ALL, with a lower response to standard chemotherapy. Some recent studies established the fundamental role of epigenetic aberrations such as DNA hypermethylation, to influence patients' outcome and response to chemotherapy. Moreover, L-asparaginase is an important chemotherapeutic agent for treatment of ALL and resistance to this drug has been linked to ASNS expression, which can be silenced through methylation. Therefore, we tested whether the sensitivity of T-ALL cell lines towards L-asparaginase is correlated to the epigenetic status of ASNS gene and whether the sensitivity can be modified by concurrent demethylating treatment. Hence we treated different T-ALL cell lines with L-asparaginase and correlated different responses to the treatment with ASNS expression. Then we demonstrated that the ASNS expression was dependent on the methylation status of the promoter. Finally we showed that, despite the demethylating effect on the ASNS gene expression, the combined treatment with the demethylating agent Decitabine could synergistically improve the L-asparaginase sensitivity in those T-ALL cell lines characterized by hypermethylation of the ASNS gene. In conclusion, this preclinical study identified an unexpected synergistic activity of L-asparaginase and Decitabine in the subgroup of T-ALL with low ASNS expression due to hypermethylation of the ASNS promoter, while it did not restore sensitivity in the resistant cell lines characterized by higher ASNS expression.

[Fatal central nervous system hemorrhage during acute lymphoblastic leukemia induction]. / Hémorragie cérébrale fatale en cours d'induction d'une leucémie aiguë lymphoblastique.

Intracerebral hemorrhage (ICH) remains a cause of death in hematologic malignancies. Asparaginase represents a key agent in the treatment of acute lymphoblastic leukemia (ALL). The toxicity of asparaginase includes coagulopathy such as thrombotic or bleeding tendency. We report a case of fatal cerebral hemorrhage in a 12-year-old girl treated for ALL. Cerebral hemorrhage occurred after three injections of L-asparaginase. The patient presented with hypofibrinogenemia (0.36g/L), associated with thrombocytopenia (24,000/mm3). Despite maximal medical and surgical treatment (platelets and fresh-frozen plasma transfusions, red blood cells transfusion, fibrinogen replacement therapy, and craniotomy discharge), the patient died. L-asparaginase is well known for its prothrombotic action. By inhibiting the synthesis of fibrinogen and factors V, VII, VIII, and IX, it causes an increased risk of bleeding, including intracranial bleeding. Predictive scores for ICH onset have been established but there is no consensus on the management of coagulation disorders induced by L-asparaginase. It is recommended to check fibrinogen and antithrombin (AT) blood values in order to substitute them if they drop to < 1 g/L for fibrinogen and < 60% for AT. The management of asparaginase-induced ICH does not differ from that of ICH of other origin. The risk of death is high, and surgical treatment has not proven superior to medical therapy in terms of mortality rates and 6-month survival. Further studies are needed to define consensus guidelines for coagulation disorders induced by asparaginase and also to define the specific management in cases of ICH in childhood hematological malignancies.

Concurrent Chemoradiation Therapy Followed by Consolidation Chemotherapy for Localized Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type.

PURPOSE: To evaluate the effectiveness of concurrent chemoradiation therapy (CCRT) with 40 Gy followed by consolidation chemotherapy for localized extranodal natural killer (NK)/T-cell lymphoma (ENKTL), nasal type. METHODS AND MATERIALS: From August 2004 to August 2012, 62 patients with newly diagnosed stage IE to IIE ENKTL underwent CCRT followed by consolidation chemotherapy. The median RT dose was 40 Gy. Cisplatin, 30 mg/m(2), was administered weekly during the RT course. Responders to CCRT were encouraged to undergo consolidation chemotherapy. Three different consolidation chemotherapy regimens were used consecutively: VIPD (etoposide, ifosfamide, cisplatin, and dexamethasone); VIDL (etoposide, ifosfamide, and dexamethasone followed by intramuscular injection of l-asparaginase); and MIDLE (methotrexate, etoposide, ifosfamide, mesna, and l-asparaginase). RESULTS: The median follow-up period was 49 months (range 8-112). After completion of CCRT, 56 patients (90.3%) had a complete response, 4 (6.4%) had a partial response, 1 (1.6%) had stable disease, and 1 patient (1.6%) had progressive disease (PD). Consolidation chemotherapy was recommended to 61 patients, after excluding the patient with PD, but was actually delivered to 58. Of these 58 patients, 56 (96.5%) had a complete response and 2 (3.5%) had PD. During the follow-up period, 17 patients (including 3 with PD) experienced progression. The median interval to progression was 11 months (range 1-61). Local failure developed in 6 patients, of whom, 2 had developed progression outside the RT field. For all patients, the 3-year overall survival, progression-free survival, and local control rates were 83.1%, 77.1%, and 92.4%, respectively. Grade ≥3 nonhematologic toxicity developed in only 3 patients (4.8%). CONCLUSIONS: Excellent clinical outcomes were achieved using CCRT with 40 Gy followed by consolidation chemotherapy. Additional investigation, however, is warranted to confirm our findings.

Effect of short-term zinc supplementation on zinc and selenium tissue distribution and serum antioxidant enzymes.

BACKGROUND: A significant association between Zn and Se homeostasis exists. At the same time, data on the influence of zinc supplementation on selenium distribution in organs and tissues seem to be absent. Therefore, the primary objective of the current study is to investigate the influence of zinc asparaginate supplementation on zinc and selenium distribution and serum superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity in Wistar rats. METHODS: 36 rats were used in the experiment. The duration of the experiment was 7 and 14 days in the first and second series, respectively. The rats in Group I were used as the control ones. Animals in Groups II and III daily obtained zinc asparaginate (ZnA) in the doses of 5 and 15 mg/kg weight, respectively. Zinc and selenium content in liver, kidneys, heart, muscle, serum and hair was assessed using inductively coupled plasma mass spectrometry. Serum SOD and GPx activity was analysed spectrophotometrically using Randox kits. RESULTS: Intragastric administration of zinc asparaginate significantly increased liver, kidney, and serum zinc content without affecting skeletal and cardiac muscle levels. Zinc supplementation also stimulated selenium retention in the rats' organs. Moreover, a significant positive correlation between zinc and selenium content was observed. Finally, zinc asparaginate treatment has been shown to modulate serum GPx but not SOD activity. CONCLUSIONS: The obtained data indicate that zinc-induced increase in GPx activity may be mediated through modulation of selenium status. However, future studies are required to estimate the exact mechanisms of zinc and selenium interplay.

Lead screening for CXCR4 of the human HIV infection receptor inhibited by traditional Chinese medicine.

The acquired immunodeficiency syndrome (AIDS) is a serious worldwide disease caused by the human immunodeficiency virus (HIV) infection. Recent research has pointed out that the G protein-coupled chemokine receptor CXCR4 and the coreceptor C-C chemokine receptor type 5 (CCR5) are important targets for HIV infection. The traditional Chinese medicine (TCM) database has been screened for candidate compounds by simulating molecular docking and molecular dynamics against HIV. Saussureamine C, 5-hydroxy-L-tryptophan, and diiodotyrosine are selected based on the highest docking score. The molecular dynamics is helpful in the analysis and detection of protein-ligand interactions. According to the analysis of docking poses, hydrophobic interactions, hydrogen bond variations, and the comparison of the effect on CXCR4 and CCR5, these results indicate Saussureamine C may have better effect on these two receptors. But for some considerations, diiodotyrosine could make the largest variation and may have some efficacy contrary to expectations.

ß-Phenylethylamine as a novel nutrient treatment to reduce bacterial contamination due to Escherichia coli O157:H7 on beef meat.

Bacterial infection by Escherichia coli O157:H7 through the consumption of beef meat or meat products is an ongoing problem, in part because bacteria develop resistances towards chemicals aimed at killing them. In an approach that uses bacterial nutrients to manipulate bacteria into behaviors or cellular phenotypes less harmful to humans, we screened a library of 95 carbon and 95 nitrogen sources for their effect on E. coli growth, cell division, and biofilm formation. In the initial screening experiment using the Phenotype MicroArray(TM) technology from BioLog (Hayward, CA), we narrowed the 190 starting nutrients down to eight which were consecutively tested as supplements in liquid beef broth medium. Acetoacetic acid (AAA) and ß-phenylethylamine (PEA) performed best in this experiment. On beef meat pieces, PEA reduced the bacterial cell count by 90% after incubation of the PEA treated and E. coli contaminated meat pieces at 10°C for one week.

In vivo evaluation of poly-l-asparagine nanocapsules as carriers for anti-cancer drug delivery.

Here, we report the in vivo proof of-concept of a novel nanocarrier, poly-l-asparagine (PASN) nanocapsules, as an anticancer targeted drug delivery system. The nanocapsules were loaded with the fluorescent marker DiD (1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate) and also with the model drug docetaxel to evaluate the biodistribution and efficacy profiles in healthy and glioma-bearing mice, respectively. Regardless of their cargo, the nanocapsules presented a size close to 180 nm, a surface charge around -40 mV and an encapsulation efficiency of 75-90%. The biodistribution study in healthy mice showed that PASN nanocapsules led to a two- and three-fold increment in the mean residence time (MRT) and area under the curve (AUC) values, respectively, compared to those of a non-polymeric nanoemulsion. Finally, the efficacy/toxicity study indicated that the encapsulated drug was as efficacious as the commercial formulation (Taxotere(®)), with the additional advantage of being considerably less toxic. Overall, these results suggest the potential of PASN nanocapsules as drug nanocarriers in anticancer therapy.

[Efficiency of treatment of adult patients with acute T-lymphoblastic leukemia according to the ALL-2009 protocol of the Russian Acute Leukemia Study Group].

AIM: To present the results of treatment in adult patients with acute T-lymphoblastic leukemia (T-ALL) according to the ALL-2009 protocol of the Russian Acute Leukemia Study Group, the basic principle of which is continuation of cytostatic treatment, early switch from prednisolone to dexamethasone, and long-term use of L-asparaginase. SUBJECTS AND METHODS: The results of diagnosis and treatment were analyzed in 70 patients with different immunological variants of T-ALL treated in the Russian multicenter trial. RESULTS: Out of the 70 patients with T-ALL, its early immunotype was determined in 32 (45.7%) cases, the thymic and mature immunotypes were found in 31 (44.3%) and 7 (10%) cases, respectively. The median age of the patients with T-ALL was 28 (ranged from 15 to 54) years; men were twice more than women (48 and 22, respectively). Bone marrow lesion was noted in all the patients with early T-ALL and in 80% of the patients with thymic and mature T-ALL. The enlarged mediastinum was significantly more frequently detected in mature T-ALL (100%) than in its early (53.4%) and thymic (60.7%) variants. Therapeutic effectiveness was evaluated in 58 patients. An analysis was made in January 2013. Induction therapy resulted in complete remission in 49 (84.5%) patients. The refractory course of the disease was recorded in 5 (8.6%) cases; early death was in 4 (6.9%). The rate of complete remission in thymic T-ALL, unlike in the early (72%) and mature (71.4%) variants, was significantly higher (100%) due to the absence of resistant forms and early mortality. Moreover, it should be noted that only the patients with early T-ALL (16%) died during the induction phase. In the patients with different variants of T-ALL, the overall and relapse-free survival rates were not significantly different, accounting for 67.2 and 76.2%, respectively. Multivariate analysis revealed no prognostically unfavorable factors that determined long-term results. CONCLUSION: The ALL-2009 protocol is reproducible in any regions of the Russian Federation and highly efficient in treating patients with T-ALL.

Medication induced diabetes during induction in pediatric acute lymphoblastic leukemia: prevalence, risk factors and characteristics.

INTRODUCTION: Medication induced diabetes (MID) during induction therapy (MIDi) in patients with acute lymphoblastic leukemia (ALL) is not well characterized in children, with recent studies yielding conflicting results. PURPOSE: The purpose of the study was to describe the prevalence of MIDi and risk factors for its development. METHODS: We retrospectively gathered demographic, disease course and treatment data on 363 patients aged 1 to 17.9 years diagnosed with ALL at a pediatric tertiary care hospital between 1998 and 2005. MIDi was defined as blood glucose ≥200 mg/dL (11.1 mmol/L) on at least 2 separate days during induction. RESULTS: Fifty-seven subjects (15.7%) developed MIDi during the study period. Patients ≥10 years were more likely to develop MIDi than those <10 years (odds ratio [OR] 9.6, 95% confidence interval [CI] 5.1-17.8). BMI percentile among those with MIDi (mean ± SD 58.2 ± 31.0) did not differ from those without MIDi (52.2 ± 32.0, P = 0.429). The presence of Trisomy 21 (OR 3.6, 95% CI 1.1-11.4, P = 0.030) and CNS involvement at diagnosis (OR 3.8, 95% CI 1.4-10.1, P = 0.009) were associated with an increased risk of MIDi. After adjustment for potential confounding variables, age ≥10 years and the presence of CNS disease at diagnosis remained significantly associated with MIDi. CONCLUSIONS: Older age and CNS involvement at diagnosis increase the risk of MIDi. In contrast to previous studies, higher BMI was not associated with MIDi in our population.

[Effect of tritarg on proteinogenic amino acid spectrum in blood serum and lymphocytes].

Single intragastric injection of tritarg leads to different multidirectional changes in the concentration of free proteinogenic amino acids in the blood serum and lymphocytes isolated from the blood and liver. Changes in the amino acid stock of blood and liver lymphocytes were observed 3 and 24 hours after the drug injection. The changes in concentrations of individual free amino acids are more pronounced in liver lymphocytes than in blood lymphocytes. There is a decrease in the content of proteinogenic amino acids in blood serum, which may reflect the supply of these compounds to cells and is indicative of the stimulation of polypeptide and protein synthesis.

Comparison between L-CHOP and an L-CHOP protocol with interposed treatments of CCNU and MOPP (L-CHOP-CCNU-MOPP) for lymphoma in dogs.

An L-CHOP protocol with interposed treatments of CCNU and MOPP (L-CHOP-CCNU-MOPP) was evaluated in 66 dogs with stages III-V lymphoma. Results were compared with a historical group of 71 dogs treated with an L-CHOP protocol. Complete remission (CR) rates (85 and 80%, respectively) did not differ significantly between protocols (P = 0.48). First CR duration for dogs treated with L-CHOP-CCNU-MOPP was significantly longer: median, 317 days; 2-year CR rate, 35% versus median, 298 days; 2-year CR rate, 13%, P = 0.05). For the L-CHOP-CCNU-MOPP protocol, dogs in substage-b had a 4.3 times greater hazard of having a relapse than dogs in substage-a (P = 0.002). Frequency of adverse chemotherapy-associated gastrointestinal effects did not differ between protocols (P = 0.77). Neutropenia (primarily after CCNU) occurred more frequently in dogs treated with L-CHOP-CCNU-MOPP (P < 0.001). In summary, the L-CHOP-CCNU-MOPP protocol showed an improved duration of first CR as compared with an L-CHOP protocol, but the relevance of this finding might be subject to clinical judgement.

Tolerability and efficacy of L-asparaginase therapy in pediatric patients with acute lymphoblastic leukemia.

L-asparaginase (L-ASNase) has been an essential component of multiagent chemotherapy for acute lymphoblastic leukemia in childhood for over 3 decades. There are currently 2 Food and Drug Administration (FDA)-approved formulations of L-ASNase derived from Escherichia coli and 1 non-FDA approved formulation derived from Erwinia chrysanthemi. Modifications in L-ASNase have included pegylation, which decreases drug immunogenicity and increases the half-life, allowing less frequent administration. Although L-ASNase is well-tolerated in most patients and causes little myelosuppression, significant toxicities occur in up to 30% of patients. Hypersensitivity is the most common toxicity of L-ASNase therapy and limits the further use of the drug. Other significant toxicities relate to a reduction in protein synthesis and include pancreatitis, thrombosis, central nervous system complications, and liver dysfunction. The spectrum of common toxicities and the efficacy of different formulations of L-ASNase are presented in this review.

The effect of 5 days of aspartate and asparagine supplementation on glucose transport activity in rat muscle.

The consumption of protein supplements containing amino acids is increasing around the world. Aspartate (Asp) and asparagine (Asn) are amino acids metabolized by skeletal muscle. This metabolism involves biochemical pathways that are involved in increasing Krebs cycle activity via anaplerotic reactions, resulting in higher glutamine concentrations. A connection between amino acid supplementation, glycogen concentration, and glucose uptake has been previously demonstrated. The purpose of this study was to evaluate the effect of Asp and Asn supplementation on glucose uptake in rats using three different glycogen concentrations. The results indicate that Asp and Asn supplementation in rats with high glycogen concentrations (fed state) further increased the glycogen concentration in the muscle, and decreased in vitro 2-deoxyglucose (a glucose analog) uptake by the muscle at maximal insulin concentrations. When animals had a medium glycogen concentration (consumed lard for 3 days), glucose uptake was higher in the supplemented group at sub-maximal insulin concentrations. We conclude that supplementation of Asp and Asn reduced glucose transport in rat muscle only at higher levels of glycogen. The ingestion of lard for 3 days changed the responsiveness and sensitivity to insulin, and that group had higher levels of insulin sensitivity with Asp and Asn supplementation.

Efficacy of combination chemotherapy for treatment of gastrointestinal lymphoma in dogs.

BACKGROUND: Chemotherapy for multicentric canine lymphoma has favorable results. The gastrointestinal (GI) tract is the most common extranodal site of canine lymphoma, but there have been no prospective studies to determine outcome when dogs with GI lymphoma are treated with chemotherapy. HYPOTHESIS: Treatment with a multiagent chemotherapy protocol is associated with a poor outcome in dogs with GI lymphoma. ANIMALS: Eighteen dogs with histologically confirmed GI lymphoma. METHODS: Prospective clinical trial in which dogs with GI lymphoma were treated with a 20-week combination chemotherapy protocol consisting of induction and consolidation phases. RESULTS: Thirteen dogs had primary GI lymphoma and 5 had multicentric lymphoma with GI involvement. The majority of the lymphomas (63%) were of T-cell origin. Overall remission rate was 56%; 9 dogs achieved a complete remission for a median of 86 days (range, 22-420 days) and 1 dog achieved a partial remission for 26 days. Overall median survival time was 77 days (range, 6-700 days). Dogs that failed to achieve a remission (10 versus 117 days; P= .002) or had diarrhea at initial presentation (70 versus 700 days; P < .001) had shorter survival times. CONCLUSION AND CLINICAL IMPORTANCE: The response and survival of dogs with GI lymphoma treated with multiagent chemotherapy is poor but long-term survival is possible.

Intracerebroventricular injection of L-aspartic acid and L-asparagine induces sedative effects under an acute stressful condition in neonatal chicks.

The present study was conducted to clarify the central functions of L-aspartic acid (Asp) and L-asparagine (Asn) during an acute stressful condition in chicks. Intracerebroventricular (i.c.v.) injection of Asp and Asn (0.84 micromol) attenuated the vocalization that normally occurs during social separation stress. Asp decreased the time spent in active wakefulness and induced sedation. Asn had a similar effect to Asp, although somewhat weaker. However, i.c.v. injection of Asp and Asn further enhanced plasma corticosterone release under social separation stress. Taken together, the i.c.v. injection of Asp and Asn has sedative effects under an acute stressful condition, which does not involve the hypothalamic-pituitary-adrenal axis.

Do aspartate and asparagine acute supplementation influence the onset of fatigue in intense exercise?

AIM: Oxaloacetic acid represents a fundamental intermediary in the metabolism of energy substrate. Asparagine and aspartate constitute precursor compounds of this substance. Therefore, they could affect tricarbossilic acids cycle. Besides, it was suggested that supplementation with aspartate and asparagine determines a muscular glycogen sparing during strenuous physical exercise, even if the real effectiveness remain controversial. The aim of the present pilot study was to evaluate the hypothesis that a supplementation with oxaloacetate precursors, precisely aspartate and asparagine, could improve sport performance during high intensity endurance exercise. METHODS: We recruited 15 male trained athletes, aged from 20 to 30 years (mean age: 24.13+/-3.87 years), practicing triathlon. We administered them placebo or aspartate (7 g) and asparagine (7 g) mixture, using a double blind technique, before performing an exhaustion stress test on cycloergometer carried out to 90% of each athlete's maximum oxygen consumption, previously determined. RESULTS: We evaluated lactatemia through earlobe punctures at the end of warming up, at the maximum effort and at recovery time (3 min, 5 min, 10 min, 15 min, 30 min). Furthermore, subjects were submitted to three blood samples from brachial artery in order to assess the glycemia (before the exercise, at the end of the exercise, and 30 min after the end of the exercise). CONCLUSION: The analysis of these parameters and the results of the ergometric tests after amino acids assumption indicate that acute supplementation with aspartate and asparagine do not significantly affect physical performance in athletes practicing high intensity exercises, and that acute administration of aspartate does not cause a sparing of muscle glycogen concentration.

Pharmacokinetics of poly(hydroxyethyl-l-asparagine)-coated liposomes is superior over that of PEG-coated liposomes at low lipid dose and upon repeated administration.

'Stealth' liposomes with a poly(ethylene glycol) (PEG) coating are frequently studied for drug delivery and diagnostic purposes because of their prolonged blood circulation kinetics. However, several recent reports have demonstrated that PEG-liposomes are rapidly cleared at single low lipid doses (<1 micromol/kg) and upon repeated administration (time interval between the injections 5 days-4 weeks). Recently, poly(amino acid)-based stealth liposome coatings have been developed as alternative to the PEG-coating. In this study, the pharmacokinetic behavior of liposomes coated with the poly(amino acid) poly(hydroxyethyl-l-asparagine) (PHEA) was evaluated at low lipid doses and upon repeated administration in rats. Blood circulation times and hepatosplenic localization of PHEA-liposomes were assessed after intravenous injection. When administered at a dose of 0.25 micromol/kg or less, PHEA-liposomes showed significantly longer blood circulation times than PEG-liposomes. A second dose of PHEA-liposomes 1 week after the first injection was less rapidly cleared from the circulation than a second dose of PEG-liposomes. Although the mechanisms behind these observations are still not clear yet, the use of PHEA-liposomes appears beneficial when single low lipid doses and/or repeated dosing schedules are being applied.