Nucleotide-mediated calcium signaling in rat cortical astrocytes: Role of P2X and P2Y receptors

ATP is the dominant messenger for astrocyte-to-astrocyte calcium-mediated communication. Definition of the exact ATP/P2 receptors in astrocytes and of their coupling to intracellular calcium ([Ca(2+)](i)) has important implications for brain physiology and pathology. We show that, with the only exception of the P2X(6) receptor, primary rat cortical astrocytes express all cloned ligand-gated P2X (i.e., P2X(1-5) and P2X(7)) and G-protein-coupled P2Y receptors (i.e., P2Y(1), P2Y(2), P2Y(4), P2Y(6), and P2Y(12)). These cells also express the P2Y-like UDP-glucose receptor, which has been recently recognized as the P2Y(14) receptor. Single-cell image analysis showed that only some of these receptors are coupled to [Ca(2+)](i). While ATP induced rapid and transient [Ca(2+)](i) increases (counteracted by the P2 antagonists suramin, pyridoxal-phosphate-6-azophenyl-2'-4'-disulfonic acid and oxidized ATP), the P2X(1)/P2X(3) agonist alphabetameATP produced no changes. Conversely, the P2X(7) agonist BzATP markedly increased [Ca(2+)](i); the presence and function of the P2X(7) receptor was also confirmed by the formation of the P2X(7) pore. ADP and 2meSADP also produced [Ca(2+)](i) increases antagonized by the P2Y(1) antagonist MRS2179. Some cells also responded to UTP but not to UDP. Significant responses to sugar-nucleotides were also detected, which represents the first functional response reported for the putative P2Y(14) receptor in a native system. Based on agonist preference of known P2 receptors, we conclude that, in rat astrocytes, ATP-induced calcium rises are at least mediated by P2X(7) and P2Y(1) receptors; additional receptors (i.e., P2X(2), P2X(4), P2X(5), P2Y(2), P2Y(4), and P2Y(14)) may also contribute.     

Development of diagnostic criteria for defining sleep disturbance in Alzheimer's disease

This article proposes new standards for identifying, defining, and naming sleep/wake cycle disturbances associated with Alzheimer's disease (AD) to aid in more effective research, including the development and testing of potential treatments. Many AD patients develop sleep/wake cycle disturbances associated with distress, depression, and sleep disturbances in the caregiver, as well as early nursing home placement for the patient. The Food and Drug Administration Psychopharmacological Drugs Advisory Committee has emphasized the need for a comprehensive diagnostic system. A key point made by the committee was that behavioral problems associated with dementia (including sleep and chronobiological disturbances) are scientifically and clinically valid targets of pharmacologic treatment. However, current diagnostic criteria preclude development of FDA-acceptable studies of pharmacological interventions because they do not include the required specific indications for treatment. This article attempts to develop better-defined provisional criteria with the goal of promoting epidemiological, physiological, and, especially, pharmacological research on sleep/wake disturbances.     

Longitudinal study of symptoms and cognitive function in chronic schizophrenia

There is conflicting evidence of a relationship between changes in symptoms and cognitive functioning in schizophrenia. This study investigated longitudinal changes in psychopathology and cognitive functioning in chronic schizophrenia utilising three different dimensional models of symptomatology. Sixty-two patients diagnosed with DSM-IV schizophrenia or schizoaffective disorder were examined on two occasions over a period of 6 months for symptom improvement, measured by Positive and Negative Syndrome Scale (PANSS) [Kay et al., Schizophr. Bull. 13 (1987) 261]. Participants also completed a comprehensive battery of neuropsychological tasks designed to assess attention, verbal and non-verbal memory, psychomotor processing and executive/frontal functioning on both occasions. Twenty-five control subjects were assessed for comparison purposes. Severity of negative symptoms predicted poor neuropsychological performance on IQ, verbal fluency and memory measures at occasion one. However, using regression analyses, significant improvements in symptom ratings over time using two-, three- or five-dimensional models did not predict improvements in any aspect of cognitive functioning measured, except motor speed. The results do not suggest a causal relationship between the course of symptoms and neuropsychological functioning in chronic schizophrenia.     

Disruption of the Cys5-Cys7 disulfide bridge in the platelet glycoprotein Ibbeta prevents the normal maturation and surface exposure of GPIb-IX complexes

This work aimed at elucidating the molecular genetic defect in two related patients with Bernard-Soulier syndrome (BSS) phenotype. Flow cytometric analysis revealed undetectable levels of platelet glycoproteins (GP), Ibalpha and IX, although plasma glycocalicin was detectable in both cases. The complete sequencing of GPIbalpha, GPIbbeta, and GPIX revealed the presence of a single point mutation, a G to A substitution, in codon 30 of GPIbbeta, that changes Cys5 to Tyr. The parents and sibling of the patients, heterozygotes for this mutation, were asymptomatic and they all showed a reduced platelet content of GPIbalpha and GPIX. Transient transfection of the mutant GPIbalpha subunit failed to render surface expression of GPIbalpha and exerted a dominant-negative effect on the surface exposure of the GPIb-IX complex. Metabolic labelling and immunoprecipitation analysis of transfected cells indicated that [5Tyr]GPIbbeta may associate with GPIX and GPIbalpha, but the maturation of the GPIb-IX complex is impaired. Substitution of either Cys5 or Cys7 by Ala failed to show surface expression of GPIb-IX, suggesting that the Cys5- Cys7 disulfide loop in GPIbbeta is essential for the efficient processing and trafficking of GPIb-IX complexes toward the plasma membrane. Our findings indicate that the identified novel GPIbbeta mutation is responsible for the BSS phenotype of the patients and provide an explanation for the molecular mechanism underlying the reduced platelet content of GPIb-IX complex in the heterozygous individuals.     

Videonasopharyngoscopy in patients with 22q11.2 deletion syndrome (Shprintzen syndrome)

INTRODUCTION: Velo-cardio-facial syndrome (VCFS) (also known as DiGeorge sequence, conotruncal anomaly face syndrome, 22q11.2 deletion syndrome among other labels) is now recognized as the most common syndrome associated with cleft palate and velopharyngeal insufficiency. VCFS has been associated with medially positioned internal carotid arteries. This anomaly has been associated with obvious posterior pharyngeal pulsations seen on videonasopharyngoscopy. The purpose of this paper is to study the role of videonasopharyngoscopy for the evaluation of patients with VCFS and submucous cleft palate. MATERIALS AND METHODS: Twenty patients with submucous cleft palate, velopharyngeal insufficiency, and 22q11.2 deletion as demonstrated by fluorescence in situ hybridization (FISH) were studied. Also, 20 patients with submucous cleft palate, and without abnormalities in the FISH procedure, were studied as controls. All patients from both groups underwent videonasopharyngoscopy. A double-blind procedure was utilized whereby all videonasopharyngoscopies were independently revised by the two examiners. RESULTS: Both examiners coincided that 17 patients with VCFS demonstrated obvious posterior pharyngeal pulsations seen on videonasopharyngoscopy. In contrast, both examiners agreed that none of the patients from the control group showed posterior pharyngeal pulsations. CONCLUSIONS: Videonasopharyngoscopy seems to be a safe and reliable procedure for evaluating patients with VCFS. The observations of posterior pharyngeal wall pulsations on videonasopharyngoscopy should alert clinicians to the diagnosis of VCFS. Also, the findings of videonasopharyngoscopy can be useful for preventing the risk of damage to the carotid arteries during velopharyngeal surgery. This indicates another important role of videonasopharyngoscopy in the preoperative assessment of children for palatopharyngoplasty.     

Synergistic activity of the N-terminal peptide of human lactoferrin and fluconazole against Candida species

In light of the need for new antifungal regimens, we report that at noncandidacidal concentrations, the lactoferrin-derived peptide hLF(1-11), which is highly active against fluconazole-resistant Candida albicans, acts synergistically with fluconazole against this yeast and a fluconazole-sensitive C. albicans strain as well as C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis. When these yeasts were exposed to hLF(1-11) for 5 min and then incubated with fluconazole, they were killed effectively, while no candidacidal activity was observed when they were incubated first with fluconazole and then exposed to the peptide, indicating that the candidacidal activity is initiated by the peptide while fluconazole is only required during the effector phase. Investigations of the effect of azide, which inhibits mitochondrial respiration, on the activity of combinations of hLF(1-11) and fluconazole against fluconazole-resistant C. albicans revealed that it inhibits this activity, even when added during the effector phase only. As expected, azide inhibited the accumulation of rhodamine 123 in mitochondria and the production and release of ATP by C. albicans that occurred upon exposure to the combination of hLF(1-11) and fluconazole. Accordingly, oxidized ATP (oATP), an antagonist of ATP receptors, completely blocked the candidacidal activity of the hLF(1-11)-fluconazole combination, whereas oATP did not block the activity when its presence was restricted to the effector phase. The candidacidal activity of combinations of hLF(1-11) and fluconazole, which is initiated by the peptide through the involvement of energized mitochondria, renders fluconazole-resistant C. albicans sensitive to this azole.     

Public stem cell banks: considerations of justice in stem cell research and therapy

If stem cells fulfill their therapeutic promise, moving them from the laboratory into the clinic will raise several concerns about justice. One concern is that, for biological reasons alone, stem cell‐based therapies might not be available for every patient who needs one. Worse, depending on how we address the problem of biological access, they might benefit primarily white Americans. We can avoid this outcome—although at a cost—by carefully selecting the stem cells we make available.     

Food habits are associated with lipid peroxidation in an elderly population

OBJECTIVE: The purpose of this study was to assess the association between dietary intake and lipid peroxidation. DESIGN: Cross-sectional population analysis from an ongoing prospective study. Malondialdehyde (MDA) was measured as a marker of lipid peroxidation. Diet was assessed through direct observation and food frequency questionnaire. SUBJECTS: Participants with no missing data were 162 nonsmoking elderly individuals residing in 7 institutions across Asturias (Spain). STATISTICAL ANALYSES PERFORMED: Comparisons of adjusted group means by tertiles of plasma MDA were made by analysis of variance. Stepwise regression analysis was done using MDA as a dependent variable and food intake as an independent variable. Food intakes were categorized into quartiles and logistic regression was applied to calculate the odds ratio for being in the highest tertile of plasma MDA. RESULTS: Consumption of potatoes had an independent direct effect and accounted for a sizeable proportion of the variation in plasma MDA levels (18%, P<.001). In addition to potatoes, other foods that had an apparently independent effect on plasma MDA were eggs, cooked vegetables, and red wine (R(2)=0.028, 0.023 and 0.018, respectively). In this study, dietary factors accounted for 25% of the variation in plasma MDA levels. CONCLUSION: Identifying nutritional determinants of oxidative stress is important because of its negative health effect. Consumption of cooked vegetables and moderate intake of wine has been shown to be appropriate for reducing the risk of oxidative damage. On the contrary, caution must be used with the intake of potatoes because we have found a positive association with MDA levels. Further studies are required to investigate the mechanism(s) of this association and whether it is related to the preparation method or to the potato itself.     

Development and evaluation of cultural food frequency questionnaires for South Asians,Chinese, and Europeans in North America

We developed three ethnic food frequency questionnaires (FFQs) to characterize the diets of South Asian, Chinese, and European immigrants. FFQs were developed from foods reported in the diet records and recalls of 29 South Asians, 25 Chinese, and 20 Europeans participating in a pilot study from 1995-1996 in Hamilton, Ontario, Canada. The FFQ and a seven-day diet record were then administered to 342 South Asians, 317 Chinese, and 346 Europeans participating in the Study of Health Assessment and Risk in Ethnic groups (SHARE) in three Canadian centers from 1996-1998. For FFQ validation, a subset of these participants completed a second seven-day diet record and second FFQ 8 to 10 months later. The FFQ generally underestimated macronutrient and overestimated micronutrient intake compared with the records. Consumption of most macronutrients was lower among South Asians. Energy-adjusted deattenuated correlation coefficients between the records and second FFQ ranged from 0.32 to 0.73 (South Asians), 0.17 to 0.84 (Chinese), and 0.30 to 0.83 (Europeans). The FFQs generally performed well and will be used to investigate diet-disease relations in SHARE. Lower correlations for dietary fats among Chinese persons (0.17 to 0.31) may be improved with more direct questions on the FFQ regarding brand, type, and amount of oil consumed in stirfry servings.