Antimicrobial activity of flavonoids glycosides and pyrrolizidine alkaloids from propolis of Scaptotrigona aff. postica

Stingless bees, or simply meliponines, are a large group of bees (about 550 described species), comprising the tribe Meliponini. They belong in the family Apidae, and are closely related to Apis mellifera. Scaptotrigona affinis postica Latreille, 1807 from northeast of Brazil is popularly known as “tubi” in Maranhão State. Flavones di-C-glycosides, and the pyrrolizidine alkaloid 3-methoxy-7-(2-methylbutyryl)-9-echimidinyl retronecine (7) were reported previously in propolis from S. postica and detected only in samples collected in October, November and December. The presence of pyrrolizidine alkaloids and their N-oxides were reported in honey and pollen. In the present study, the preparative liquid chromatography in reversed-phase column from ethanolic extract of propolis allowed the separation of fractions 40AEP and 40 MEP, which were analyzed by LC-MS. Many pyrrolizidine alkaloids, among them, lithosenine (14), lithosenine arabinoside (19), 7-angeloyl-9-(2,3- dihydroxybutyryl) retronecine (1), 7-(2- methylbutyryl) retronecine (3), 9-sarracinoyl retronecine (13) and viridinatine (8), besides the flavonoids schaftoside (15), aromadendrin-7-O-methyl ether (12), 7- methoxy-5,6,3’,4’,5’,6’-hexahydroxy-flavone-3-O-glucuronide (11), mangiferin (10) and mangiferin-O-methyl ether (17) were detected in these fractions. Fraction 40MEP showed antibacterial effect against gram positive and gram negative bacterial pathogens with MIC ranging from 62.5 μg/mL to 200 μg/mL, while fractions 40AEP and 40MEP showed antimicrobial activity against gram negative bacteria, including Escherichia coli D31- streptomycin resistant. The cells were treated with 40MEP and 40AEP at a concentration of 200 μg/mL and were not observed statistical difference between treated and untreated cells.

Spontaneous pneumothorax in cocaine users.

BACKGROUND: Pneumothorax is one of the respiratory toxic effects of cocaine inhalation. The literature counts several cases, some associated to other respiratory conditions such as pneumomediastinum, haemoptysis and others not requiring surgical treatment. AIM: We present a series of nonHIV cocaine-inhaler subjects who underwent video-assisted thoracoscopic surgery (VATS) for isolated spontaneous pneumothorax. DESIGN: Nine subjects, with a mean age of 24 ± 4 years, admitting cocaine inhalation, developed spontaneous pneumothorax and underwent 10 surgical treatments by means of VATS, at our Institution. RESULTS: Previous pneumothorax occurred in six cases episodes ranged from 0 to 5 (mean 1.6 ± 1.6). Chest computed tomography (CT) scan showed abnormalities in seven cases. All subjects underwent lung apicectomy, apical pleurectomy and mechanical pleurodesis. Seven subjects had also bullectomy. In all cases the visceral pleura was partially covered by fibrinous exudate. Histology of the lung showed small foreign body granulomatous inflammation in fibrotic and/or emphysematous pulmonary parenchyma. Relapse of pneumothorax occurred in one subject at 60 days and it was surgically treated. Mean follow-up was 150 ± 38 months (range 120-239). All subjects are now well, with no evidence of pneumothorax. CONCLUSIONS: Spontaneous pneumothorax in cocaine-inhaler subjects is a reality of which physicians need to be aware. Chest CT scan might not reveal abnormalities. Macroscopically the lung might presents bullae and/or peculiar visceral pleura. Foreign body granulomas observed in the specimens suggest that the particulate component of inhaled substances can injure the lung. Surgical treatment of the bullous disease and mechanical pleurodesis can provide a long-term follow-up without relapse of pneumothorax.

A case of endobronchial paraganglioma.

Paragangliomas are rare lung tumours; endobronchial localisation is even more rare. This report describes the case of a 59-year-old patient with a symptomatic endobronchial paraganglioma successfully resected by means of pulmonary lobectomy. Recognition of this uncommon tumour can lead to a correct diagnosis and therapeutic strategy.

The antiviral effect of mollusk mucus on measles virus

Measles is a viral disease highly contagious spread by respiratory transmission. Although infection can be controlled by vaccination, numerous cases of measles have been registered in many areas of the world, highlighting the need for additional interventions. Terrestrial gastropods exude mucus on their body surface when traveling, to protect the body from mechanical injury, desiccation or contact with harmful substances. The mucus of mollusks has been studied as a source of new natural compounds with diverse biological activities. In this study, the antiviral activity of the mucus of the land slug P. boraceiensis was demonstrated in vitro using Vero cells infected with measles virus. The crude sample and four fractions were tested in cultures infected with measles virus and the antiviral activity was assessed by the cytopathic effect in infected cell cultures as well as by immunofluorescence and qPCR. Fractions 39 and 50 of the mucus from P. boraceiensis were analyzed by HPLC-DAD-ESI-MS/MS and infrared spectroscopy. A mixture of polyunsaturated fatty acids was found in the two fractions. A reduction in the growth of the measles virus was observed, measured by qPCR, with a protection index of 80% in Vero cells infected with measles and treated with fraction 39. Fraction 39 exhibited the best antiviral action in vitro and high contents of hydroxy-tritriacontapentaenoic acid and hydroxy-pentatriacontapentaenoic acid were found in this fraction. (C) 2016 Elsevier B.V. All rights reserved.

Clinical and molecular characterization of Rubinstein-Taybi syndrome patients carrying distinct novel mutations of the EP300 gene.

Rubinstein-Taybi syndrome (RSTS) is a rare congenital neurodevelopmental disorder characterized by postnatal growth deficiency, skeletal abnormalities, dysmorphic features and cognitive deficit. Mutations in two genes, CREBBP and EP300, encoding two homologous transcriptional co-activators, have been identified in ˜55% and ˜3-5% of affected individuals, respectively. To date, only eight EP300-mutated RSTS patients have been described and 12 additional mutations are reported in the database LOVD. In this study, EP300 analysis was performed on 33 CREBBP-negative RSTS patients leading to the identification of six unreported germline EP300 alterations comprising one deletion and five point mutations. All six patients showed a convincing, albeit mild, RSTS phenotype with minor skeletal anomalies, slight cognitive impairment and few major malformations. Beyond the expansion of the RSTS-EP300-mutated cohort, this study indicates that EP300-related RSTS cases occur more frequently than previously thought (˜8% vs 3-5%); furthermore, the characterization of novel EP300 mutations in RSTS patients will enhance the clinical practice and genotype-phenotype correlations.

Insights into genotype-phenotype correlations from CREBBP point mutation screening in a cohort of 46 Rubinstein-Taybi syndrome patients.

The genetic basis of Rubinstein-Taybi syndrome (RSTS), a rare, sporadic, clinically heterogeneous disorder characterized by cognitive impairment and a wide spectrum of multiple congenital anomalies, is primarily due to private mutations in CREBBP (approximately 55% of cases) or EP300 (approximately 8% of cases). Herein, we report the clinical and the genetic data taken from a cohort of 46 RSTS patients, all carriers of CREBBP point mutations. Molecular analysis revealed 45 different gene alterations including 31 inactivating (21 frameshift and 10 nonsense), 10 missense and 4 splicing mutations. Bioinformatic tools and transcript analyses were used to predict the functional effects of missense and splicing alterations. Of the 45 mutations, 42 are unreported and 3 were described previously. Recurrent mutations maybe a key tool in addressing genotype-phenotype correlations in patients sharing the same defects (at the genomic or transcript level) and specific clinical signs, demonstrated here in two cases. The clinical data of our cohort evidenced frequent signs such as arched eyebrows, epicanthus, synophrys and/or frontal hypertrichosis and broad phalanges that, previously overlooked in RSTS diagnosis, now could be considered. Some suggested correlations between organ-specific anomalies and affected CREB-binding protein domains broaden the RSTS clinical spectrum and perhaps will enhance patient follow-up and clinical care.

Antiviral action of hydromethanolic extract of geopropolis from scaptotrigona postica against antiherpes simplex virus (HSV-1)

The studies on chemical composition and biological activity of propolis had focused mainly on species Apis mellifera L. (Hymenoptera: Apidae). There are few studies about the uncommon propolis collected by stingless bees of the Meliponini tribe known as geopropolis. The geopropolis from Scaptotrigona postica was collected in the region of Barra do Corda, Maranhão state, Brazil. The chemical analysis of hydromethanolic extract of this geopropolis (HMG) was carried out through HPLC-DAD-ESI-MS/MS and the main constituents found were pyrrolizidine alkaloids and C-glycosyl flavones. The presence of alkaloids in extracts of propolis is detected for the first time in this sample. The antiviral activity of HMG was evaluated through viral DNA quantification experiments and electron microscopy experiments. Quantification of viral DNA from herpes virus showed reduction of about 98% in all conditions and concentration tested of the HMG extract. The results obtained were corroborated by transmission electron microscopy, in which the images did not show particle or viral replication complex. The antiviral activity of C-glycosyl flavones was reported for a variety of viruses, being observed at different points in the viral replication. This work is the first report about the antiviral activity of geopropolis from Scaptotrigona postica, in vitro, against antiherpes simplex virus (HSV).

Open repair for aortic occlusive disease: indication, techniques, results, tips and tricks.

AIM: The aim of this article was to review indications, techniques, and outcomes of a series of open repair for aortic occlusive disease. METHODS: Between 1991 and 2013, 1071 patients (917 men, 154 women; mean age 62.6 years) underwent open repair for aortoiliac occlusive disease. According to TASC II classification, 123 patients (11.5%) had type B lesions, 343 (32%) type C, and 605 (56.5%) type D. Among type D lesions, 138 patients had Leriche's Syndrome with complete aortic occlusion. Nine hundred and eight aortobifemoral bypasses, 114 axillo-bifemoral bypasses, 42 aortic endarterectomies with patch aortoplasty, and 7 thoracobifemoral bypasses were performed. Associated endarterectomy of abdominal aorta was required in 191 patients (18.5%), of the femoral arteries in 297 (28.7%). RESULTS: Perioperatively mortality was 0.6%; perioperative morbidity included cardiac (3.4% of patients), respiratory (2.6%), as well as acute renal insufficiency (2.6%). There were 26 (2.5%) cases of intraoperative distal embolization, 9 (0.8%) of acute graft thrombosis and 9 (0.8%) of bleeding requiring surgical revision within the first 24 hours after surgery. Sixty-one groin complications were reported in 57 patients (5.3%). During a mean follow-up time of 74 months (range 1-264), calculated actuarial occlusion-free survival at 12, 24, and 36 months was 94.8%, 91.8% and 87.2%, respectively. The limb-salvage rate in patients with critical limb ischemia was 87.3%. There were 11 (1%) graft infections. CONCLUSION: Open repair is a ductile strategy and may be tailored according to the patient clinical condition and disease anatomy. Long-term patency is excellent with low perioperative mortality and reasonable morbidity rates.

Comparative chemistry of propolis from eight brazilian localities.

Propolis is a complex honeybee product with resinous aspect, containing plant exudates and beeswax. Their color, texture, and chemical composition vary, depending on the location of the hives and local flora. The most studied Brazilian propolis is the green (alecrim-do-campo) type, which contains mainly prenylated phenylpropanoids and caffeoylquinic acids. Other types of propolis are produced in Brazil, some with red color, others brown, grey, or black. The aim of the present work was to determine the chemical profiles of alcohol and chloroform extracts of eight samples of propolis, corresponding to six Brazilian regions. Methanol and chloroform extracts were obtained and analyzed by HPLC/DAD/ESI/MS and GC/MS. Two chemical profiles were recognized among the samples analyzed: (1) black Brazilian propolis, characterized chiefly by flavanones and glycosyl flavones, stemming from Picos (Piauí state) and Pirenópolis (Goiás state); (2) green Brazilian propolis, characterized by prenylated phenylpropanoids and caffeoylquinic acids, stemming from Cabo Verde (Bahia state), Lavras and Mira Bela (Minas Gerais state), Pariquera-Açu and Bauru (São Paulo state), and Ponta Grossa (Paraná state). The present work represents the first report of prenylated flavonoids in Brazilian propolis and schaftoside (apigenin-8-C-glucosyl-6-C-arabinose) in green propolis.

Flavonol glycosides found in hydroethanolic extracts from Tilia cordata, a species utilized as anxiolytics / Flavonóides glicosídeos encontrados no extrato hidroalcoólico de Tilia cordata, espécie usada como ansiolítico

Tilia species, among which is Tilia cordata Mill. (Tiliaceae), have been used in folk medicine as anxiolytic. The hydroethanolic extract was analyzed by using liquid chromatography with mass spectrometry HPLC-DAD-ESI-MS/MS in negative ion mode, and its chemical composition was compared to flavonoids reported as anxiolytics. The major flavonoids found were: quercetin-3,7-di-O-rhamnoside, kaempferol-3,7-di-O-rhamnoside and kaempferol 3-O-(6"-p-coumaroyl glucoside) or tiliroside. The anxiolytic activity of the genus Tilia has been attributed to the presence of quercetin and kaempferol derivatives, while the anxiolytic activity of T. americana var. Mexicana was attributed to tiliroside, which was also found among the major constituents of this species.

As espécies de Tilia, entre elas, a Tilia cordata Mill. (Tiliaceae) são utilizadas como ansiolíticas na medicina popular. O extrato hidroalcoólico foi analisado usando cromatografia líquida acoplada à espectrometria de massas HPLC-DAD-ESI/MS/MS no modo negativo e a sua composição química foi comparada com os flavonóides já reportados como ansiolíticos. Os principais flavonóides encontrados foram: quercetina-3,7-di-O-rhamnosideo, canferol-3,7-di-O-rhamnosideo, e canferol 3-O-(6"-p-cumaroil glucosideo) ou tilirosideo. A atividade ansiolítica do gênero Tília tem sido atribuída à presença de derivados de canferol e quercetina, enquanto que a atividade ansiolítica da T. americana var. Mexicana foi atribuída ao tilirosideo, o qual também foi encontrado entre os principais constituintes desta espécie.

The dysregulation profile in children and adolescents: a potential index for major psychopathology?

We here review the literature on Child Behaviour Checklist-Dysregulation Profile (CBCL-DP) index, which potentially represents a developmental profile of major psychopathology in early adulthood. The understanding of the neural underpinnings of children and adolescents with altered regulation of affect and behaviour may ultimately help in planning strategies to prevent psychiatric syndromes during development.

Appropriate medication prescribing in elderly patients: how knowledgeable are primary care physicians? A survey study in Parma, Italy.

WHAT IS KNOWN AND OBJECTIVE: Increasing attention is being paid to inappropriate medication prescribing for the elderly. A growing body of studies have detected a prevalence of inappropriate prescribing ranging from 12% to 40% worldwide, including Regione Emilia-Romagna, Italy. To improve quality of prescribing, a multi-phase pilot project in the Local Health Unit (LHU) of Parma, Regione Emilia-Romagna, was established. This phase aimed to assess primary care physicians' knowledge of appropriate prescribing in elderly patients. METHODS: In total, 155 primary care physicians (51% of the total), convened by the LHU of Parma for an educational session, were asked to complete anonymously a 19-item paper survey. Knowledge of inappropriate medication use in the elderly was assessed using seven clinical vignettes based on the 2002 Beers Criteria. Topics tested included hypertension, osteoarthritis, arrhythmias, insomnia and depression. Data regarding physician's perceived barriers to appropriate prescribing for elderly patients were also collected. To evaluate the relationship between physician knowledge scores and physician characteristics, physicians were classified as having a 'low score' (three or below) or a 'high score' (six or more) with respect to their knowledge of prescribing for the elderly. RESULTS AND DISCUSSION: All physicians completed the survey. Most physicians (88%) felt confident in their ability to prescribe appropriate medications for the elderly. Thirty-nine physicians (25%) received a 'high score' compared to 26 (17%) who received a 'low score'. 'Lower score' respondents had been in practice for a longer time (P < 0·05) than 'higher score' respondents. Perceived barriers to appropriate prescribing included potential drug interactions (79% of respondents) and the large number of medications a patient is already taking (75%). WHAT IS NEW AND CONCLUSION: The study results show an unsatisfactory knowledge of appropriate prescribing among primary care physicians in the LHU of Parma, especially among older physicians. Educational strategies tailored to primary care physicians should be establish to enhance knowledge in this area and improve quality of prescribing.

Increased oxidized low density lipoprotein associated with high ceruloplasmin activity in patients with active acromegaly.

OBJECTIVE: Active acromegaly is associated with increased mortality from cardiovascular causes. Several studies have shown increased atherogenic risk factors and biomarkers of inflammation and atherosclerosis in association with growth hormone excess. The aim of this study was to evaluate oxidized low density lipoprotein (oxLDL) levels and some modulators of LDL oxidative modification in patients with acromegaly. DESIGN: Open transversal study. PATIENTS: Fifteen patients with active acromegaly and 15 controls were studied. MEASUREMENTS: We evaluated the levels of oxLDL, thiobarbituric acid reactive substances (TBARS), ceruloplasmin, bilirubin, uric acid and total reactive antioxidant potential, and the activities of ceruloplasmin, myeloperoxidase, superoxide distmutase, paraoxonase 1, and platelet activating factor acethylhydrolase. Statistical analysis was performed including body mass index as a covariate or as a fixed variable. RESULTS: Patients with acromegaly showed significantly higher levels of oxLDL (120 +/- 19 vs. 86 +/- 20 U/l, P < 0.001) and endothelin (P < 0.05), increased ceruloplasmin activity (P < 0.01) and a trend towards higher values in TBARS concentration (P = 0.07) in comparison to healthy controls. OxLDL was positively associated with GH, IGF-I and its binding protein 3 (r = 0.63, P < 0.001; r = 0.53, P < 0.01; and r = 0.56, P < 0.01; respectively). OxLDL showed direct associations with endothelin-1 (r = 0.53, P < 0.01) and ceruloplasmin activity (r = 0.43, P < 0.05). The other parameters evaluated were similar in both groups. CONCLUSIONS: The increase in plasma oxLDL levels, a direct marker of the plaque formation, could constitute a link between atherosclerosis and active acromegaly. LDL oxidation would not be the consequence of diminished antioxidant defences, but of an enhancement in prooxidant factors like ceruloplasmin.

The CT-arthrography in the antero-inferior glenoid labral lesion: Pictorial presentation and diagnostic value

Objective: To present the Computed Tomography (CT)-Arthrography appearance of the most common types of anterior labral lesion and to assess the diagnostic value of this technique in the detection and classification of the antero-inferior labral tears in glenohumeral joint instability. Materials and Methods: The pre-operative CT-Arthrography records of 43 patients; who underwent surgery for anterior shoulder instability; were retrospectively evaluated independently by two radiologists. The data were compared with arthros- copic results and the diagnostic accuracy of CT-Arthrography was calculated to detect the labral lesion and the agreement between the CT-Arthrography lesions classification and the arthroscopy classification. Results: The CT-Arthrography sensitivity; specificity and accuracy were: 92/ 89(reader 1/reader 2); 86/ 86and 91/ 88respectively. The CT-Arthrography classification was correct in 86of cases. Conclusions: CT-Arthrography appears to be an accurate means for identification and classification of the anterior labral tears and; identifying the labral degeneration; this technique can be very helpful in the selection of patient for arthroscopic stabilization of the shoulder

Immunocytochemistry of p16INK4a in liquid-based cervicovaginal specimens with modified Papanicolaou counterstaining.

AIM: To evaluate the feasibility and value of a modified Papanicolaou counterstain for p16(INK4a) immunostaining in liquid-based cervicovaginal samples. METHODS: Immunocytochemical analyses were carried out with p16(INK4a) and modified Papanicolaou counterstain on 81 liquid-based samples, including 23 of within normal limits (WNL), 6 of low-grade squamous intraepithelial lesion (LSIL), 20 of high-grade squamous intraepithelial lesion (HSIL), 16 of atypical squamous cells of undetermined significance (ASC-US) and 16 of atypical squamous cells, high-grade lesion cannot be excluded (ASC-H). Results were compared with histological or cytological follow-up. For comparison, samples from 29 more cases (10 of LSIL, 10 of ASC-H and 9 of HSIL) were immunostained with p16(INK4a) and conventionally counterstained with haematoxylin. The intensity of immunostaining in cases of squamous intraepithelial lesion (SIL) was assessed using a 0-3 scoring system. Interobserver agreement was calculated by kappa statistics. RESULTS: Expression of p16(INK4a) was detected in 3 of 23 cases of WNL, 4 of 6 cases of LSIL, all cases of HSIL, 5 of 16 cases of ASC-US and 13 of 16 cases of ASC-H. Excluding two cases with no residual dysplastic cells in the immunocytochemistry, all cases of cervical intraepithelial neoplasia (CIN)2 or CIN3 at follow-up expressed p16(INK4a) and none of the p16(INK4a)-negative cases showed a high-grade lesion at follow-up. No evident differences in pattern or intensity of p16(INK4a) expression were observed between the specimens of the study and control groups. Interobserver agreement was significantly better in the study group than in the group with conventional immunostaining (combined kappa 0.773 v 0.549; p<0.05), and still better, albeit statistically not significant, than with conventional immunostaining and cervical smear test together (combined kappa 0.773 v 0.642). CONCLUSION: Immunocytochemistry with p16(INK4a) and modified Papanicolaou counterstain may add to the cervicovaginal cytology the full potentiality of p16(INK4a) without the need of a further slide and the risk of loss of dysplastic cells, yet maintaining the typical morphological features of the smear test.

Endogenous hypertriglyceridemia intensifies the course of cerulein-induced pancreatitis in rat: relation with changes in the VLDL composition.

AIMS: To study if the course of cerulein-induced pancreatitis in rats changes in a state of triglyceride-rich lipoprotein metabolism alteration. METHODS: Two groups of rats received control diet during a 90-day period (A) and sucrose-rich diet to induce endogenous hypertriglyceridemia (B). Subgroups A2 and B2 received i.p. 45 microg cerulein/kg body weight (to induce acute pancreatitis). Histological examination of pancreas tissue, serum pancreatic lipase, lipoprotein profile and VLDL chemical composition were assessed. Then, pancreatic lipase hydrolytic activity on VLDL-triglycerides was evaluated in vitro. RESULTS: Cellular vacuolization was observed in all of the cerulein-injected rats, but only in subgroup B2 fat necrosis was present. Serum triglycerides were higher in subgroup B1 than in subgroup A1 (mean +/- SEM, mg/dl 123,77 +/- 25.7 vs. 65.8 +/- 7, p < 0.01). Triglycerides from rats fed with sucrose-rich diet, decreased after cerulein-induced pancreatitis (80.38 +/- 11.3 vs. 123,77 +/- 25.7, p < 0.02). Moreover, the endogenous hypertriglyceridemic rats showed an increment of VLDL triglyceride content, which decreased when rats were injected with cerulein. A negative correlation was found between VLDL-triglyceride content and serum pancreatic lipase activity (r = 0.58, p < 0.02). The in vitro assay showed a decrease in VLDL-triglyceride content post incubation with pancreatic lipase enriched serum (mean +/- SD: 59.2 +/- 27.7%, p < 0.01). CONCLUSIONS: The endogenous hypertriglyceridemia intensifies the course of cerulein-induced pancreatitis and it could be related to the decrease in VLDL-triglycerides as a consequence of pancreatic lipase hydrolytic activity.

Endobain E, a brain endogenous factor, is present and modulates NMDA receptor in ischemic conditions.

We have isolated from rat cerebral cortex an endogenous Na(+), K(+)-ATPase inhibitor, termed endobain E, which modulates glutamatergic N-methyl-d-aspartate (NMDA) receptor. This endogenous factor allosterically decreases [(3)H]dizocilpine binding to NMDA receptor, most likely acting as a weak channel blocker. In the present study we investigated whether endobain E is present in the cerebral cortex of rats subjected to ischemia and modulates NMDA receptor exposed to the same conditions. Ischemia-reperfusion was carried out by bilateral occlusion of common carotid arteries followed by a 15-min reperfusion period. Elution profile of brain soluble fraction showed that endobain E is present in cerebral cortex of ischemia-reperfusion rats. On assaying its effect on synaptosomal membrane Na(+), K(+)-ATPase activity and [(3)H]dizocilpine binding to cerebral cortex membranes prepared from animals without treatment, it was found that the endogenous modulator isolated from ischemia-reperfusion rats was able to inhibit both enzyme activity and ligand binding. On the other hand, endobain E prepared from rats without treatment also decreased binding to cerebral cortex or hippocampal membranes obtained from animals exposed to ischemia-reperfusion. Since ischemia decreases tissue pH and NMDA receptor activity varies according to proton concentration, pH influence on endobain E effect was tested. Endobain E ( approximately 80 mg original tissue) decreased [(3)H]dizocilpine binding 25% at pH 7.4 or 8.0 but 90% at pH 6.5. These results demonstrate that endobain E is present and also able to modulate NMDA receptor in the short-term period that follows cerebral ischemia and that its effect depends on proton concentration, suggesting greater NMDA receptor modulation by endobain E at low pH, typical of ischemic tissues.