Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 89
Filter
1.
J Endocrinol Invest ; 46(7): 1397-1406, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36708456

ABSTRACT

PURPOSE: 25OHD levels in patients with Prader-Willi Syndrome (PWS), the most frequent cause of genetic obesity with a peculiar fat mass distribution, are still debated. Insulin resistance (IR), Body Mass Index-SDS (BMI-SDS), Growth Hormone Therapy (GHT), and puberty onset seem to interact with 25OHD levels. The objectives of the study are: (1) To analyze 25OHD levels in pediatric PWS patients in comparison with a control group (CNT) (2) To evaluate a possible correlation between BMI-SDS, HOMA-IR, puberty, GHT, and 25OHD levels. METHODS: This is a retrospective case-control, multicenter study. Data were collected among 8 different Italian Hospitals (outpatient clinics), over a period of four years (2016-2020). We included 192 genetically confirmed PWS and 192 CNT patients, aged 3-18 years, matched 1:1 for age, gender, BMI-SDS, Tanner stage, sun exposure, and month of recruitment. RESULTS: No statistically significant differences in 25OHD levels were observed between the PWS population and the CNT (PWS 24.0 ng/mL vs CNT 22.5 ng/mL, p > 0.05), OR = 0.89 (95% CI 0.58-1.35). We observed a slight, although non-significant, reduction in 25OHD levels comparing NW and OB populations. HOMA-IR, puberty onset, genotype and GHT (previous or ongoing) did not show statistically significant correlation with 25OHD levels. CONCLUSIONS: Our findings could be useful for clinicians to optimize the therapeutic management as well as to increase awareness of PWS.


Subject(s)
Human Growth Hormone , Insulin Resistance , Prader-Willi Syndrome , Child , Humans , Adolescent , Prader-Willi Syndrome/drug therapy , Case-Control Studies , Retrospective Studies , Human Growth Hormone/therapeutic use , Italy , Vitamin D/therapeutic use
2.
Nutr Metab Cardiovasc Dis ; 32(5): 1301-1307, 2022 05.
Article in English | MEDLINE | ID: mdl-35260309

ABSTRACT

BACKGROUND AND AIM: Screening for pediatric hypertension (HTN) is based on several measurements of blood pressure (BP) in different visits. We aimed to assess its feasibility in outpatient youths with overweight/obesity (OW/OB) in terms of adherence to two-repeated measurements of BP and to show the features of youths who missed the follow-up and the predictive role of clinical and/or anamnestic features on confirmed HTN. METHODS AND RESULTS: Six hundred, eighty-eight youths (9-17 years) with OW/OB, consecutively recruited, underwent a first measurement of BP. Those exhibiting BP levels within the hypertensive range were invited to repeat a second measurement within 1-2 weeks. Confirmed HTN was diagnosed when BP in the hypertensive range was confirmed at the second measurement. At entry, 174 youths (25.1%) were classified as hypertensive. At the second visit, 66 youths (37.9%) were lost to follow-up. In the remaining 108 participants, HTN was confirmed in 59, so that the prevalence of confirmed HTN was 9.5% in the overall sample; it was higher in adolescents than children (15.9% vs 6.8%, P = 0.001). HTN at first visit showed the best sensitivity (100%) and a good specificity (91%) for confirmed HTN. The association of HTN at first visit plus familial HTN showed high specificity (98%) and positive predictive value of 70%. CONCLUSION: The high drop-out rate confirms the real difficulty to obtain a complete diagnostic follow up in the obese population. Information about family history of HTN may assist pediatricians in identifying those children who are at higher risk of confirmed HTN.


Subject(s)
Hypertension , Adolescent , Blood Pressure , Blood Pressure Determination , Child , Feasibility Studies , Humans , Hypertension/diagnosis , Hypertension/epidemiology , Obesity/diagnosis , Obesity/epidemiology , Overweight/diagnosis
3.
J Endocrinol Invest ; 43(4): 461-468, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31637675

ABSTRACT

OBJECTIVE: To evaluate the association between high uric acid (UA), reduced estimated glomerular filtration rate (eGFR), and non-alcoholic fatty liver disease (NAFLD) in outpatient children and adolescents with overweight (OW) or obesity (OB). METHODS: Anthropometric, biochemical, hepatic ultrasound and eGFR data were available from 2565 young people with OW/OB (age 5-18 years). eGFR was calculated using the Schwartz's bedside formula and reduced eGFR (ReGFR+) was defined by a value < 90 mL/min/1.73 m2. High UA was defined as ≥ 75th percentile by sex in children and adolescents. RESULTS: The population was stratified in four categories: (1) normal eGFR and absence of NAFLD (ReGFR-/NAFLD-) (n = 1,236); (2) ReGFR+ and absence of NAFLD (ReGFR+/NAFLD- (n = 155); (3) normal eGFR and presence of NAFLD (ReGFR-/NAFLD+) (n = 1019); (4) presence of both conditions (ReGFR+/NAFLD+) (n = 155). Proportions of youth with high UA across the four categories were 17%, 30%, 33% and 46%, respectively (P < 0.0001). Young people with high levels of UA had odds ratio (95% CI) of 2.11 (1.43-3.11) for ReGFR+; 2.82 (2.26-3.45) for NAFLD+; and 5.04 (3.45-7.39) for both conditions (P < 0.0001 for all), independently of major confounders. CONCLUSIONS: High levels of UA were independently associated with ReGFR, NAFLD and the combination of both conditions in young people with OW/OB. The strength of this association was the highest in cases presenting both reduced eGFR and NAFLD. UA may serve as marker to identify patients at risk for these conditions.


Subject(s)
Glomerular Filtration Rate/physiology , Non-alcoholic Fatty Liver Disease/etiology , Obesity/complications , Renal Insufficiency, Chronic/etiology , Uric Acid/blood , Child , Female , Humans , Liver/diagnostic imaging , Liver/metabolism , Liver/physiopathology , Male , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/physiopathology , Obesity/metabolism , Obesity/physiopathology , Renal Insufficiency, Chronic/metabolism , Renal Insufficiency, Chronic/physiopathology , Ultrasonography
4.
J Biol Regul Homeost Agents ; 33(2): 593-599, 2019.
Article in English | MEDLINE | ID: mdl-30945510

ABSTRACT

Gastroesophageal reflux disease (GERD) may be frequently associated with asthma in children and may affect asthma control. Proton pump inhibitors (PPI) are commonly prescribed in asthmatic children, despite uncertain efficacy on respiratory symptoms and risk of relevant adverse effects.


Subject(s)
Alginates/therapeutic use , Asthma/drug therapy , Gastroesophageal Reflux/chemically induced , Magnesium/therapeutic use , Proton Pump Inhibitors/therapeutic use , Alginates/adverse effects , Asthma/complications , Child , Humans , Magnesium/adverse effects , Proton Pump Inhibitors/adverse effects
5.
J Biol Regul Homeost Agents ; 29(2 Suppl 1): 80-3, 2015.
Article in English | MEDLINE | ID: mdl-26634592

ABSTRACT

Probiotics are able to restore microbiome and the normal intestinal permeability, improve the immunological function of gut barrier and reduce the intestinal inflammatory response and the production of pro-inflammatory cytokine characteristics of local and systemic allergic inflammation. Clinical studies have demonstrated the efficacy of probiotics in the treatment of various clinical conditions such as atopic dermatitis and food allergies and in the primary prevention of atopy. Recent studies have shown that oral administration of certain probiotic exerts therapeutic effects in the treatment of allergic respiratory diseases such as asthma and rhinitis.

6.
J Biol Regul Homeost Agents ; 29(2 Suppl 1): 137-41, 2015.
Article in English | MEDLINE | ID: mdl-26634602

ABSTRACT

ß2-agonists reduce airflow limitation by improving airway diameter as a consequence of a direct action on airway smooth muscle. ß;2-agonists can be broadly classified according to their duration of action: short-acting ß2-agonists (SABAs), including albuterol, terbutaline and fenoterol, have pharmacodynamics half–lives between 2 and 6 h and long-acting ß2-agonists (LABAs), including salmeterol and formoterol, require twice daily treatment. SABAs are often used “as needed” for asthma exacerbations and before exercise in the presence of exercise-induced bronchospasm. LABAs provide longer symptom control, which is a particularly useful feature for preventing night-time symptoms. There are two main LABAs, salmeterol and formoterol. This review focused on the recent data published on this topic.

8.
Clin Ter ; 164(5): e383-6, 2013.
Article in English | MEDLINE | ID: mdl-24217840

ABSTRACT

Bowel obstruction resulting from colorectal and ovarian cancer is a serious and distressing complication of these malignancies. This may be caused by diffuse peritoneal carcinomatosis, bulky masses filling the pelvis and abdomen or postoperative adhesions, and should be carefully worked out by pre-operative imaging. We report the case of a small bowel obstruction and intestinal ischemia caused by a bulky (20x40 cm in diameter) cystic ovarian neoplasm that was found to be a stage IA G2 cystadenocarcinoma, successfully managed by uterus-sparing surgery.


Subject(s)
Abdomen, Acute/etiology , Cystadenocarcinoma/complications , Intestinal Obstruction/etiology , Intestine, Small/blood supply , Ischemia/etiology , Ovarian Neoplasms/complications , Aged, 80 and over , Constipation/etiology , Cystadenocarcinoma/diagnostic imaging , Cystadenocarcinoma/pathology , Cystadenocarcinoma/surgery , Emergencies , Female , Humans , Intestinal Obstruction/surgery , Intestine, Small/pathology , Intestine, Small/surgery , Neoplasm Staging , Ovarian Neoplasms/diagnostic imaging , Ovarian Neoplasms/pathology , Ovarian Neoplasms/surgery , Ovariectomy , Remission Induction , Tomography, X-Ray Computed , Vomiting/etiology
9.
Article in English | MEDLINE | ID: mdl-21348823

ABSTRACT

Pediatric pain management underwent many changes since the undertreatment of pain in children was reported in the literature in 1980. Increasing data also suggest that long-term behavioural effects can be observed in children, following pain episodes as early as in the neonatal period. Therefore, the knowledge about safe and effective management of pain in children should be applied with greater effectiveness into clinical practice. Other advances in the field include the findings of long-term residual behavioural and metabolic effects induced by pain experienced during the critical periods of development in laboratory animals. Recent data in laboratory animals and clinical data in children suggest that early repeated and/or severe pain and other stressful procedures applied in the perinatal periods may produce not only behavioral, but also important hormonal, immune and metabolic long-term effects. In this paper we shall report data on some metabolic conditions described in adult humans following disruption of hormonal-metabolic programming produced in the peri-natal period. Quite similar signs can be found between animal models and human conditions, most of them being connected with hypothalamus-pituitary-adrenal hormones (HPA) dysfunction. In addition, some signs in animal models, such as overweight and abdominal overweight are prevented by treatment with the µ- and δ-opioid receptor antagonist naloxone during the lactating period. This indicates that some long-term consequences following stress received during the early phases of life in mammals may be bound to the HPA system dysregulation, whereas others are bound to different (e,g., opioid) endogenous brain receptors and/or neuromediators alteration.


Subject(s)
Diabetes Mellitus, Type 2/physiopathology , Pain/physiopathology , Adult , Animals , Animals, Newborn , Child , Female , Hormones/physiology , Humans , Hypothalamo-Hypophyseal System/physiopathology , Infant, Newborn , Male , Mice , Models, Biological , Naloxone/pharmacology , Oligonucleotides, Antisense/genetics , Oligonucleotides, Antisense/therapeutic use , Pain/drug therapy , Pituitary-Adrenal System/physiopathology , Pregnancy , Pro-Opiomelanocortin/antagonists & inhibitors , Pro-Opiomelanocortin/genetics , Stress Disorders, Post-Traumatic/drug therapy , Stress Disorders, Post-Traumatic/physiopathology , Stress, Physiological , Stress, Psychological , Translational Research, Biomedical
10.
Am J Transplant ; 11(3): 528-35, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21219580

ABSTRACT

Early risk-prediction is essential to prevent cardiac allograft vasculopathy (CAV) and graft failure in heart transplant patients. We developed multivariate models to identify patients likely to experience CAV, severe CAV, and failure due to CAV, at 1, 5 and 10 years. A cohort of 172 patients was followed prospectively for 6.7 ± 3.9 years. Logistic regression models were developed and cross-validated using bootstrap resampling. Predictive markers of atherothrombosis (myocardial fibrin deposition, and loss of vascular antithrombin and tissue plasminogen activator) and arterial endothelial activation (intercellular adhesion molecule-1 expression) were measured in serial biopsies obtained within 3 months posttransplant. Most markers were univariately associated with outcome. Multivariate models showed that loss of tissue plasminogen activator was the dominant and, in most cases, only predictor of long-term CAV (p < 0.001), severe CAV (p < 0.001), and graft failure due to CAV (p < 0.001). The models discriminated patients having adverse outcomes, had particularly high negative predictive values (graft failure due to CAV: 99%, 99% and 95% at 1, 5 and 10 years) and predicted event incidence and time to event. Early absence of atherothrombotic risk identifies a patient subgroup that rarely develops CAV or graft failure, implying that this low-risk subgroup could possibly be followed with fewer invasive procedures.


Subject(s)
Biomarkers/metabolism , Graft Rejection/diagnosis , Heart Failure/diagnosis , Heart Transplantation/adverse effects , Vascular Diseases/diagnosis , Vascular Diseases/etiology , Adult , Early Diagnosis , Female , Graft Rejection/etiology , Graft Rejection/metabolism , Heart Failure/etiology , Heart Failure/metabolism , Humans , Immunoenzyme Techniques , Male , Middle Aged , Models, Statistical , Prognosis , Prospective Studies , Risk Factors , Transplantation, Homologous , Vascular Diseases/metabolism
11.
G Ital Med Lav Ergon ; 33(3 Suppl): 339-42, 2011.
Article in Italian | MEDLINE | ID: mdl-23393871

ABSTRACT

Some studies reported high levels of severe burnout syndrome in emergency workers. We compared different categories of health care workers (129 of Medicine Department e 47 of Laboratory analysis Department) and emergency workers (42 of 118 and 37 of Emergency Department) Subjects were administered the Organizational Checkup System (OCS) to evaluate subjects' risk of burnout and their perception of their own work role and of their organizational environment The operators of 118 showed a condition of wellbeing and a less tendency to burnout. This Finding was accompanied to a better perception of their own work role and of their organizational environment.


Subject(s)
Burnout, Professional/epidemiology , Emergency Service, Hospital , Health Personnel , Occupational Diseases/epidemiology , Adolescent , Adult , Female , Humans , Male , Middle Aged , Personnel, Hospital , Surveys and Questionnaires , Young Adult
12.
Vision Res ; 49(6): 583-93, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19948107

ABSTRACT

Gestalt factors of collinearity and similarity facilitate two fundamental perceptual tasks: grouping elements into figures and segmentation of figures from the ground. We have used a global-local paradigm to examine the psychophysical and neural correlates of these processes in humans: observers discriminated between orientations of either a three-Gabor group (grouping), or of a central Gabor within the group (segmentation). Groups were centered on a background of differently oriented Gabors. In both tasks, accuracy was increased by the collinearity (Experiment 1) and similarity (Experiment 2) of elements within the three-Gabor group. ERP correlates of facilitation differed across tasks. For segmentation, they were indexed by increased amplitude of negative ERP components, specific for processing textures, peaking at 75-250 and 150-250 ms, respectively. For grouping, collinearity and similarity had different effects. Collinearity produced a positive polarity deflection between 40 and 179 ms (i.e. the opposite to segmentation). This task-dependent switch in sign of polarity change, without corresponding changes in the stimulus or perception, reflects distinct neural mechanisms for collinear facilitation in grouping and segmentation. In contrast, similarity reduced positivity at 275 ms. Results show similar modulation of segmentation components via the distinct mechanism underlying collinearity and similarity, but distinct modulation of grouping components via collinearity and similarity.


Subject(s)
Pattern Recognition, Visual/physiology , Adult , Discrimination, Psychological/physiology , Electroencephalography/methods , Evoked Potentials, Visual/physiology , Female , Humans , Male , Orientation , Photic Stimulation/methods , Psychophysics , Young Adult
13.
Addict Biol ; 10(2): 187-95, 2005 Jun.
Article in English | MEDLINE | ID: mdl-16191672

ABSTRACT

Several studies indicate long-term cognitive impairment of MDMA (ecstasy) users. In the present study we attempted to establish whether electrophysiological correlates of low-level cognitive processes present a long-term alteration, dependent on the level of use of ecstasy. We addressed this issue by investigating amplitude and latency of VEPs related to a very simple discrimination task involving sustained attention (arousal). Eight heavy-MDMA users, eight moderate-MDMA users and 18 drug-free control subjects were asked to discriminate whether the digit at the centre of the screen was 1 or 2. None of the subjects (except one) had used MDMA in the 6 months previous testing. We measured psychophysical performance and EEG, recorded in Oz and Fz during task execution. The heavy-MDMA users made significantly more errors than the other two groups (p < .05). Moreover, they presented reduced amplitude but not latency of VEPs in both Oz and Fz. The effect in Oz is present in P200 (for heavy users only, p < .05) and in P300 components (for both MDMA groups; heavy users: p < .001, moderate users: p < .0.5). In Fz, the amplitude effect is present in N250 (for heavy users only, p < .05) and in P300 components (for both MDMA groups; heavy users: p < .05, moderate users: p < .05). The three groups do not differ in early components, reflecting low-level processing. These results provide evidence of long-term electrophysiological abnormality displayed by ecstasy users and agree with the suggestion that even typical recreational doses of ecstasy are sufficient to cause long-term altered cortical activity in humans.


Subject(s)
Amphetamine-Related Disorders/physiopathology , Central Nervous System/drug effects , Evoked Potentials, Visual/physiology , Hallucinogens/adverse effects , N-Methyl-3,4-methylenedioxyamphetamine/adverse effects , Adult , Central Nervous System/physiopathology , Cognition Disorders/chemically induced , Cognition Disorders/diagnosis , Electroencephalography , Event-Related Potentials, P300/physiology , Female , Humans , Male , Neuropsychological Tests , Time
14.
EMBO J ; 20(7): 1640-50, 2001 Apr 02.
Article in English | MEDLINE | ID: mdl-11285228

ABSTRACT

Neurotrophins (NTs) play an essential role in modulating activity-dependent neuronal plasticity. In this context, the site and extent of NT secretion are of crucial importance. Here, we demonstrate that the activation of phospolipase C (PLC) and the subsequent mobilization of Ca(2+) from intracellular stores are essential for NT secretion initiated by both Trk and glutamate receptor activation. Mutational analysis of tyrosine residues, highly conserved in the cytoplasmic domain of all Trk receptors, revealed that the activation of PLC-gamma in cultured hippocampal neurons and nnr5 cells is necessary to mobilize Ca(2+) from intracellular stores, the key mechanism for regulated NT secretion. A similar signalling mechanism has been identified for glutamate-mediated NT secretion-which in part depends on the activation of PLC via metabotropic receptors-leading to the mobilization of Ca(2+) from internal stores by inositol trisphosphate. Thus, PLC-mediated signal transduction pathways are the common mechanisms for both Trk- and mGluRI-mediated NT secretion.


Subject(s)
Isoenzymes/metabolism , Nerve Growth Factors/metabolism , Receptor, trkA/metabolism , Receptors, Metabotropic Glutamate/metabolism , Signal Transduction , Type C Phospholipases/metabolism , Animals , Brain-Derived Neurotrophic Factor/metabolism , Calcium/metabolism , Cell Line , Hippocampus/cytology , Hippocampus/metabolism , Inositol 1,4,5-Trisphosphate/metabolism , Intracellular Fluid/metabolism , Neurons/metabolism , Phospholipase C gamma , Phosphorylation , Rats , Rats, Wistar , Receptor, trkA/genetics , Receptors, AMPA/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Tyrosine/metabolism
15.
Eur J Pharm Sci ; 11(4): 291-8, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11033072

ABSTRACT

Bile acids may play a role in the pathogenesis of intestinal inflammation by activating the signalling pathways that control cell proliferation, among other cell systems. We investigated the action of different bile acids, particularly chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA), on steady-state and transcriptional regulation of the protooncogene c-fos, involved in the regulation of cell proliferation and differentiation, in colon carcinoma Caco-2 cells. Specific bile acids had a stimulatory effect of on the expression of c-fos mRNA. This proved to be concentration- and time-dependent and may be partly due to an increase in the rate of transcription of the corresponding gene rather than to any change in the stability of mRNA. In Caco-2 cells exposed to 250 microM CDCA for 1 h a maximal increase of c-fos mRNA ( approximately 2.5-fold induction over the control) was observed; deoxycholic acid (DCA; 250 microM) and lithocholic acid (LCA; 250 microM) were less effective (approximately 2-fold induction over the control). UDCA and cholic acid (CA) did not modify c-fos gene expression in this cell line. Finally, we investigated the role of protein kinase C (PKC) in transcriptional regulation of the c-fos gene by bile acids. Although induction of c-fos by 12-O-tetradecanoyl 13-acetate (10 nM), a potent PKC activator, was completely antagonised by bis-indolyl-maleimide I (1 microM); only about 40% of the bile acid-mediated rise in c-fos mRNA was blocked. Thus it appears that PKC, as well as other signalling pathways, is involved in CDCA-, DCA- and LCA-induced c-fos gene expression.


Subject(s)
Chenodeoxycholic Acid/pharmacology , Cholagogues and Choleretics/pharmacology , Genes, fos/drug effects , Ursodeoxycholic Acid/pharmacology , Bile Acids and Salts/pharmacology , Bile Acids and Salts/physiology , Caco-2 Cells/drug effects , Dactinomycin/pharmacology , Dose-Response Relationship, Drug , Genes, fos/physiology , Humans , Nucleic Acid Synthesis Inhibitors/pharmacology , Protein Kinase C/drug effects , Protein Kinase C/metabolism , RNA, Messenger/drug effects , RNA, Messenger/metabolism , Transcription, Genetic/drug effects , Transcription, Genetic/physiology
16.
Neurosci Lett ; 273(3): 167-70, 1999 Oct 08.
Article in English | MEDLINE | ID: mdl-10515185

ABSTRACT

In this study we characterized calcitonin (CT) receptors in human neuroblastoma IMR 32 cells. Saturation binding assays indicated that [125I]-human CT bound with high affinity to IMR 32 cell membranes (K(d) = 253.6 pM; Bmax = 3.84 fmol/ mg protein). In competition binding studies, human adrenomedullin displayed high affinity for these sites (IC50 = 30 nM) whereas human alpha calcitonin-gene related peptide (alphaCGRP; IC50 = 145 nM) and human amylin (IC50 = 415 nM) showed lower affinity. These peptides increased cAMP levels in viable cells; the relative potencies were: human CT > human adrenomedullin > human cCGRP > or = human amylin. The expression of mRNA coding for the published sequences of the human calcitonin receptor and of the human calcitonin receptor-like receptorwas evaluated by reverse transcriptase-polymerase chain reaction. Electrophoretic analysis did not confirm the occurrence of mRNA coding for the above mentioned receptors in these cells. This study suggests the presence of a novel, putative CT receptor in IMR 32 cells.


Subject(s)
Amyloid/metabolism , Calcitonin Gene-Related Peptide/metabolism , Cyclic AMP/metabolism , Neuroblastoma/metabolism , Peptides/metabolism , Receptors, Calcitonin/metabolism , Adrenomedullin , Binding, Competitive , Cells, Cultured , Humans , Islet Amyloid Polypeptide , Reverse Transcriptase Polymerase Chain Reaction
17.
Spat Vis ; 12(4): 467-83, 1999.
Article in English | MEDLINE | ID: mdl-10493097

ABSTRACT

To isolate the mechanisms responsible for spatial interactions in visual search, we investigated the effects of inter-element distance and positional jittering in both simple (in/s) and combined-feature (inverted V in Vs) search tasks in which the observer had to find a target in a background of similar nontargets. Thresholds, defined as the stimulus duration for 75% correct, were measured for 'present' and 'absent' target conditions as a function of background numerosity (ranging from 4 to 64 background elements), independently for four inter-element distances and three positional jittering conditions. Results show: (1) both simple and combined-feature search involve a parallel, capacity limited process, (2) thresholds for parallel search of simple features are directly related to inter-element distance whereas this has little effect on thresholds in combined-feature search, and (3) positional jittering has a direct effect on thresholds in combined-feature search and an inverse effect in simple-feature search. These results indicate that two different mechanisms of spatial interactions are involved in parallel search. The activation of each of the two mechanisms depends on the stimulus used. In parallel search for simple and dissimilar features, the underlying mechanism is a short-range one, based on lateral inhibition, whereas the parallel search for combined and similar features is based on a nontarget grouping mechanism which relies on facilitatory interactions between regular elements.


Subject(s)
Distance Perception/physiology , Space Perception/physiology , Computer Terminals , Humans , Observer Variation , Orientation/physiology , Photic Stimulation , Reference Values , Sensory Thresholds
18.
Microsc Res Tech ; 45(4-5): 262-75, 1999.
Article in English | MEDLINE | ID: mdl-10383119

ABSTRACT

In previous experiments the activity-dependent secretion of nerve growth factor (NGF) from native hippocampal slices and from NGF-cDNA transfected hippocampal neurons showed unusual characteristics [Blochl and Thoenen (1995) Eur J Neurosci 7:1220-1228; (1996) Mol Cell Neurosci 7:173-190]. In both hippocampal slices and cultured hippocampal neurons the activity-dependent secretion proved to be independent of extracellular calcium, but dependent on the release of calcium from intracellular stores. Under different experimental conditions, Goodman et al. [(1996) Mol Cell Neurosci 7:222-238] reported that the high potassium-mediated secretion of brain-derived neurotrophic factor (BDNF) from hippocampal cultures was dependent on extracellular calcium. Mowla et al. [(1997) Proc 27th Annu Meet Soc Neurosci New Orleans 875.10] reported on even further-reaching differences between NGF and BDNF secretion, namely, that in hippocampal neurons and in pituitary cell lines NGF was secreted exclusively according to the constitutive pathway, whereas BDNF was exclusively sorted according to the activity-dependent regulated pathway. In view of the crucial importance of such potential differences between the processing, sorting, and secretory mechanisms of different neurotrophins for their modulatory roles in activity-dependent neuronal plasticity, a thorough analysis under comparable experimental conditions was mandatory. We demonstrate that in native hippocampal slices and adenoviral-transduced hippocampal neurons there are no differences between NGF and BDNF with respect to the subcellular distribution and mechanism of secretion; that the activity-dependent secretion of both NGF and BDNF is dependent on intact intracellular calcium stores; and that the differences between our own observations and those of Goodman et al. (ibid.) regarding the dependence on extracellular calcium do not reflect differences between NGF and BDNF sorting and secretion, but reflect the differing experimental conditions used.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Hippocampus/metabolism , Nerve Growth Factors/metabolism , Neurons/physiology , Animals , Brain-Derived Neurotrophic Factor/genetics , Calcium/metabolism , Cells, Cultured , Female , Gene Transfer Techniques , Genetic Vectors/genetics , Hippocampus/cytology , Male , Microscopy, Confocal , Nerve Growth Factors/genetics , Neurons/cytology , Neurons/drug effects , Potassium/metabolism , Rats , Rats, Wistar , Time Factors
19.
J Pharmacol Exp Ther ; 289(3): 1362-9, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10336527

ABSTRACT

In this study, we examined the presence of sigma1 and sigma2 sites in the rabbit iris-ciliary body by receptor binding and investigated their effects on intraocular pressure (IOP) in albino rabbits. The iris-ciliary body has binding sites for the sigma1-site agonist [3H](+)-pentazocine (Kd = 4.6 nM; Bmax = 212 fmol/mg protein) and sigma2 sites labeled with [3H]1,3-di-o-tolylguanidine (DTG) (Kd = 8. 2 nM; Bmax = 1120 fmol/mg protein). In competition binding studies, (+)-pentazocine and the sigma antagonist NE-100 displayed high affinity for sigma1 sites (Ki = 2.1 and 2.4 nM, respectively), whereas (+)-N-allylnormetazocine (NANM) was less potent (Ki = 178 nM). Unilateral topical (+)-pentazocine (0.01-0.1%) caused a significant dose-related reduction of IOP in ocular normotensive rabbits and in the alpha-chymotrypsin model of ocular hypertension. (+)-NANM was less potent than (+)-pentazocine. Neither compound altered the IOP of the contralateral eye, and their hypotensive activity was blocked by NE-100 that, by itself, had no effect on IOP. (-)-Pentazocine, (-)-NANM, and DTG had no effect on IOP. DTG prevented the hypotensive effect of (+)-pentazocine, suggesting that it acts as a sigma1-site antagonist. sigma-Site ligands did not affect pupil diameter or cause ocular inflammation. Topical [3H](+)-pentazocine reaches the intraocular tissues within 30 min, and its uptake in the iris-ciliary body and retina was significantly reduced by topical pretreatment with NE-100, as expected for a receptor-specific agent. Reverse-phase HPLC confirmed the presence of intact (+)-pentazocine in iris-ciliary body homogenates. sigma1-Site agonists may offer a novel class of agents potentially effective in the control of ocular hypertension.


Subject(s)
Ciliary Body/physiology , Intraocular Pressure/drug effects , Iris/physiology , Receptors, sigma/metabolism , Animals , Anisoles/pharmacology , Antipsychotic Agents/pharmacology , Binding, Competitive , Cell Membrane/metabolism , Ciliary Body/drug effects , Functional Laterality , Guanidines/pharmacokinetics , Iris/drug effects , Kinetics , Lens, Crystalline/drug effects , Lens, Crystalline/physiology , Male , Pentazocine/pharmacology , Phenazocine/analogs & derivatives , Phenazocine/pharmacology , Propylamines/pharmacology , Rabbits , Receptors, sigma/agonists , Receptors, sigma/antagonists & inhibitors , Retina/drug effects , Retina/physiology , Tritium
20.
Eur J Pharmacol ; 359(2-3): 161-70, 1998 Oct 23.
Article in English | MEDLINE | ID: mdl-9832387

ABSTRACT

The effect of the dihydropyridine derivative, 1,4-dihydro-2,6-dimethyl-4-(fluorenon-4-yl)pyridine-3,5-dicarboxyl ic acid diallyl ester (fluodipine) was studied in vitro in different rabbit, rat and guinea pig preparations and in vivo in the rabbit in order to characterize its pharmacological profile at cardiac and at vascular sites. Compared to nifedipine, fluodipine showed a similar cardiodepressant activity, and a much lower inhibitory activity on vascular contraction. The highest tissue selectivity was observed in guinea pig preparations: fluodipine was about 2-3 times more effective than nifedipine on chronotropism and inotropism in isolated atria, and about 150 times less effective on aortic strip contraction. Accordingly, fluodipine (i) showed high-affinity binding to guinea pig ventricular L-type cardiac Ca2+ channels (Ki=2.57 nM), (ii) was about 80 times less effective than nifedipine to inhibit Ca2+ influx in vascular smooth muscle cells and (iii) induced a significant reduction of heart rate in the anesthetized rabbit (ID25=8.5 mg kg(-1), i.v.) without affecting the blood pressure up to 20 mg kg(-1), whereas nifedipine showed a significant hypotensive effect at very low doses (ID25=0.18 mg kg(-1), i.v.). The pacemaker current If of rabbit sino-atrial node myocytes was not affected by fluodipine. These findings demonstrate that fluodipine exerts selective cardiodepressant activity, likely due to a higher affinity for cardiac than for vascular Ca2+ channels.


Subject(s)
Calcium Channel Blockers/pharmacology , Dicarboxylic Acids/pharmacology , Dihydropyridines/pharmacology , Vasodilator Agents/pharmacology , Anesthesia , Animals , Aorta/drug effects , Aorta/physiology , Atrial Function , Binding, Competitive , Blood Pressure/drug effects , Calcium/metabolism , Calcium Channel Blockers/metabolism , Calcium Channels/metabolism , Dicarboxylic Acids/chemistry , Dicarboxylic Acids/metabolism , Dihydropyridines/chemistry , Dihydropyridines/metabolism , Electrophysiology , Female , Guinea Pigs , Heart Atria/drug effects , Heart Rate/drug effects , In Vitro Techniques , Male , Membrane Potentials/drug effects , Myocardial Contraction/drug effects , Myocardium/cytology , Myocardium/metabolism , Nifedipine/metabolism , Nifedipine/pharmacology , Pacemaker, Artificial , Patch-Clamp Techniques , Rabbits , Rats , Rats, Sprague-Dawley , Rats, Wistar , Sinoatrial Node/drug effects , Sinoatrial Node/physiology , Vasoconstriction/drug effects
SELECTION OF CITATIONS
SEARCH DETAIL
...