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Biomedical subjects

L Guerra

Publications and source records attributed to L Guerra.

At least 19 recordsLinked to original sources
PubMed2006

NHE3 inhibits PKA-dependent functional expression of CFTR by NHERF2 PDZ interactions.

It has been shown that when CFTR and NHE3 are co-expressed on the apical membrane of the A6-NHE3 cell monolayers, the two transporters interact via a shared regulatory complex composed of NHERF2, ezrin, and PKA. We observe here that co-expression of NHE3 reduced both PKA-dependent apical CFTR expression and its activation once in place by approximately 50%. To analyze the role of NHERF2 in this process, we transfected NHE3 expressing and non-expressing A6 monolayers with NHERF2 cDNA in which its binding domains had been deleted. When only CFTR is expressed on the apical membrane, deletion of any of the NHERF2 binding domains inhibited both PKA-dependent apical CFTR expression and its activation, while when NHE3 was co-expressed with CFTR PDZ2 deletion was without effect on CFTR sorting and activity. This suggests that when the PDZ2 domain is "sequestered" by interacting with NHE3 it can no longer participate in CFTR functional expression.

Animals↗
PubMed2005

A new tool to evaluate the impact of chronic urticaria on quality of life: chronic urticaria quality of life questionnaire (CU-QoL).

BACKGROUND: Health-related quality of Life in patients with chronic urticaria is evaluated by mean of generic instruments or questionnaire designed for skin diseases. No disease-specific tool is now available for the assessment of chronic urticaria impact from patients' viewpoint. OBJECTIVE: The aim of our study is to develop and validate a new questionnaire specifically designed for the assessment of quality of life in chronic urticaria (Chronic Urticaria Quality of Life Questionnaire -- CU-Q(2)oL). METHODS: In the development phase of CU-Q(2)oL an initial list of items of 37 items was compiled and given to 80 patients with chronic urticaria; the 23 most significant items were selected and converted into questions evaluating the answers on a Likert scale of five steps. The validation procedure involved 125 patients (86 F and 39 M) (age 42.17 +/- 9.24 years). RESULTS: Following a statistical analysis, CU-Q(2)oL showed a six-dimensional structure and good levels of internal consistency for the extracted factors: Pruritus (0.79), Swelling (0.65), Impact on life activities (0.83), Sleep problems (0.77), Looks (0.83) and Limits (0.74). In stable conditions CU-Q(2)oL showed a good reliability, ranged between 0.64 and 0.92. Responsiveness to clinical changes was accomplished. DISCUSSION: These results provide evidence that CU-Q(2)oL has specificity enough for being a valid tool for detecting the relative burden of CU on subjective wellbeing, and for obtaining a global evaluation both of CU impact and of treatments, taking into account the patient's point of view. The CU-Q(2)oL was easily and quickly filled up and well accepted by the patients.

Adult↗
PubMed2005

Lipase and antibacterial activities of a recombinant protein from the accessory glands of female Phlebotomus papatasi (Diptera: Psychodidae).

The reproductive accessory glands of the adult female have a functional versatility in insects, contributing to reproduction in various ways. The major protein secreted by the accessory glands of female Phlebotomus papatasi (Diptera, Psychodidae) has already been characterised and named PhpaLIP (for P. papatasi lipase) because, in terms of its amino-acid sequence, it is very similar to a wide range of vertebrate lipases. The gene coding for PhpaLIP has now been cloned into a pQE30 vector and expressed in Escherichia coli. When the recombinant PhpaLIP was tested in vitro, it was found to have not only lipase-like activity (when p-nitrophenyl caprylate was used as the substrate) but also specific antibacterial activity against some Gram-positive and Gram-negative bacteria. The possible physiological roles of PhpaLIP in P. papatasi are discussed, in the light of these results.

Actinomycetales↗
PubMed2004

Stimulation of Xenopus P2Y1 receptor activates CFTR in A6 cells.

Nucleotide binding to purinergic P2Y receptors contributes to the regulation of a variety of physiological functions in renal epithelial cells. Here, we investigate the regulatory mechanism of the P2Y1 receptor agonist 2-methylthioadenosine diphosphate (2-MeSADP) on Cl- transport in A6 cells, a commonly used model of the distal section of the Xenopus laevis nephron. Protein and mRNA expression analysis together with functional measurements demonstrated the basolateral location of the Xenopus P2Y1 receptor. 2-MeSADP increased intracellular [Ca2+] and cAMP and Cl- efflux, responses that were all inhibited by the specific P2Y1 receptor antagonist MRS 2179. Cl- efflux was also inhibited by the cystic fibrosis transmembrane conductance regulator (CFTR) blocker glibenclamide. Inhibition of either protein kinase A (PKA) or the binding between A-kinase-anchoring proteins (AKAPs) and the regulatory PKA RII subunit blocked the 2-MeSADP-induced activation of CFTR, suggesting that PKA mediates P2Y1 receptor regulation of CFTR through one or more AKAPs. Further, the truncation of the PDZ1 domain of the scaffolding protein Na+/H+ exchanger regulatory factor-2 (NHERF-2) inhibited 2-MeSADP-dependent stimulation of Cl- efflux, suggesting the involvement of this scaffolding protein. Activation or inhibition of PKC had no effect per se on basal Cl- efflux but potentiated or reduced the 2-MeSADP-dependent stimulation of Cl- efflux, respectively. These data suggest that the X laevis P2Y1 receptor in A6 cells can increase both cAMP/PKA and Ca2+/PKC intracellular levels and that the PKC pathway is involved in CFTR activation via potentiation of the PKA pathway.

Adenosine Diphosphate↗
PubMed2004

[The availability in Spanish public hospitals of resources for diagnosing and treating sleep apnea-hypopnea syndrome].

INTRODUCTION AND OBJECTIVE: Sleep apnea-hypopnea syndrome is associated with an overall deterioration in the patients health and affects between 1 and 2 million people in Spain. The objective of the present study was to evaluate the diagnostic and therapeutic resources available in Spain for dealing with this problem in terms of both infrastructure and human resources. METHODS: We selected 461 general hospitals, 457 (99.1%) of which answered a questionnaire in the course of a telephone interview. RESULTS: At the time of response, 219 hospitals (47.5%) reported performing sleep studies. Conventional polysomnography was available in 53% of those hospitals, respiratory polygraphy was used in 42%, and oximetry in 5%. In 47% of the hospitals, continuous positive airway pressure was titrated empirically in most cases; the number of patients being treated with CPAP was 109,752, that is, 269 per 100,000 population in Spain. CONCLUSIONS: The level of resources available for diagnosing and treating sleep apnea-hypopnea syndrome, although improving, is clearly still inadequate. Currently, only 0.49 polysomnograph and 0.72 polygraph machines are available per 100,000 population, whereas 1 and 3 machines, respectively, are deemed necessary. Only 5% to 10% of the affected population has been diagnosed, and in 47% of the hospitals interviewed continuous positive airway pressure is not properly titrated. These results should be a clarion call to the health authorities to take the appropriate steps to address this health problem.

Health Care Surveys↗
PubMed2004

Permanent repigmentation of piebaldism by erbium:YAG laser and autologous cultured epidermis.

BACKGROUND: Several surgical techniques have been proposed for the treatment of piebaldism. These procedures, however, are poorly suited for the treatment of large leucodermal lesions, can cause scars and require multiple donor sites. Recently, it has been reported that autologous cultured epidermis induces scarless repigmentation of large vitiligo lesions, using a single small donor site. OBJECTIVES: To induce permanent repigmentation of large achromic lesions in patients suffering from piebaldism by means of autologous cultured epidermal grafts using a rapid, simple and non-invasive surgical procedure. METHODS: Six patients with piebaldism were enrolled in this study. Achromic epidermis was removed by means of appropriately set erbium:YAG laser and autologous cultured epidermal grafts were applied on to the recipient bed. Melanocyte content was evaluated by 3,4-dihydroxyphenylalanine reaction. The percentage of repigmentation was calculated using a semiautomatic image analysis system. RESULTS: Autologous cultured epidermis, bearing a controlled number of melanocytes, induced repigmentation of all piebald lesions. The mean percentage repigmentation was 95.45% (2791.5 cm2 repigmented/2924.2 cm2 transplanted). CONCLUSIONS: Autologous cultured epidermal grafts induce permanent and complete repigmentation of piebald lesions, in the absence of scars. Erbium:YAG laser surgery is a rapid and precise tool for disepithelialization, hence allowing treatment of large piebald lesions during a single surgical operation.

Adolescent↗
PubMed2004

Antihistamines: do they work? Further well-controlled trials involving larger samples are needed.

Histamine is one of the most important steps in the phlogistic allergic reaction. Its activity is due to the link to specific receptors on the cellular surface. H1-receptors of second generation are the most currently prescribed drugs in allergic diseases for their high selectivity, little or no central sedative effect, rapid onset of action and long half lives. Antihistamines can modulate part of immunological mechanisms involved in the pathogenesis of allergic inflammation reducing mediator release and expression of adhesion molecules, regulating the release of cytokines, chemokines and consequently inflammatory cells recruitment. The anti-inflammatory effects of cetirizine, desloratadine and levocetirizine are reviewed. Quality of life is considered too, as a main parameter in a global evaluation of the antihistamine's effects.

Anti-Allergic Agents↗
PubMed2003

Quality of life and patients' satisfaction in chronic urticaria and respiratory allergy.

BACKGROUND: Few articles are available about chronic urticaria (CU) impact on patients' quality of life (QoL). The aim of our study was to evaluate QoL in CU patients both focusing on health status and subjective satisfaction. We adopted two generic tools: SF-36 (an health status questionnaire) and SAT-P (a satisfaction profile). METHODS: Twenty-one untreated patients (five males, 16 females; aged 46.3 +/- 12.4) affected by CU, were enrolled. SF-36 and SAT-P scores of CU patients were compared with scores of a group of 27 patients with respiratory allergy. Published reference values of 608 and 241 Italian healthy subjects were used as controls, respectively, for SF-36 and SAT-P. RESULTS: Patients with CU compared with allergic patients referred significantly lower scores in physical functioning (P = 0.046), role physical (P = 0.01), bodily pain (P = 0.0001), general health (P = 0.0043) and role emotional (P = 0.04), and compared with reference sample reported lower scores in all SF-36 domains (P < 0.0001). SAT-P scores of CU patients compared with patients with respiratory allergy and with reference sample were significantly lower in many aspects of daily life. CONCLUSIONS: These results show a significant impact on health status and on subjective satisfaction in patients with CU: the symptoms affect everyday life, limiting and impairing physical and emotional functioning, and acts as an indirect burden on life satisfaction.

Adult↗
PubMed2002

Extracellular adenine nucleotides regulate Na+/H+ exchanger NHE3 activity in A6-NHE3 transfectants by a cAMP/PKA-dependent mechanism.

As potential autocrine or paracrine factors, extracellular nucleotides are known to be important regulators of renal ion transporters by activating cell surface receptors and intracellular signaling pathways. We investigated the influence of extracellular adenine nucleotides on Na+/H+ exchanger isoform 3 (NHE3) activity in A6-NHE3 cells. This is a polarized cell line obtained by stable transfection of A6 cells with the cDNA encoding the rat isoform of NHE3, which is expressed on the apical membrane. Basolateral addition of the P2Y(1) agonist, 2-MeSADP, induced an inhibition of NHE3 activity, which was prevented by preincubation with selective P2Y(1) antagonists, MRS 2179 (N6-methyl-2'-deoxyadenosine-3',5'-bisphosphate) and MRS 2286 (2-[2-(2-chloro-6-methylamino-purin-9-yl)-ethyl]-propane-1,3-bisoxy(diammoniumphosphate)). NHE3 activity was also significantly inhibited by ATP and ATP-gamma-S but not by UTP. 2-MeSADP induced a P2Y(1) antagonist-sensitive increase in both [Ca2+]i and cAMP production. Pre-incubation with a PKC inhibitor, Calphostin C, or the calcium chelator BAPTA-AM, had no effect on the 2-MeSADP-dependent inhibition of NHE3 activity, whereas this inhibition was reversed by either incubation with the PKA inhibitor H89 or by mutation of two PKA target serines (S552 and S605) on NHE3. Pre-incubation of the A6-NHE3 cells with the synthetic peptide, Ht31, which prevents the binding between AKAPs and the regulatory PKA subunits RII, also prevented the 2-MeSADP-induced inhibition of NHE3. We conclude that only the cAMP/PKA pathway is involved in the inhibition of NHE3 activity.

Adenosine↗
PubMed2002

Effects of beta-endorphin and Naloxone on in vitro maturation of bovine oocytes.

Bovine cumulus-oocyte complexes (COCs) and mural granulosa cells express the mRNA coding for the micro-opioid receptor. The addition of beta-endorphin (beta-end) to oocytes cultured in hormonally-supplemented in vitro maturation (IVM) medium had no effect on the rates of oocytes reaching the metaphase II (MII) stage, but significantly decreased the maturation rate (P < 0.05) and arrested oocytes at metaphase I (MI) after culture in hormone-free medium (P < 0.001). Naloxone (Nx) reverted this inhibitory effect of beta-end. Moreover, Nx "per se" showed a dose-dependent dual effect. When added at high concentration (10 x (-3) M), it significantly reduced the rate of oocytes in MII (P < 0.001), thus increasing the rate of oocytes arrested in MI. However, Nx added at low concentration (10 x (-8) M) significantly increased oocyte maturation (P < 0.001). High concentration of Nx induced an increase in both intracellular calcium concentration ([Ca(2+)](i)) and in the activity of the mitogen-activated protein kinase (MAPK) also called extracellular-regulated kinase (ERK) in cumulus cells of bovine COCs. Blocking the rise in [Ca(2+)](i) with the calcium chelator acetoxymethylester-derived form of bis (o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM) reversed the Nx-dependent inhibition of meiotic maturation observed at high Nx concentrations. Whereas blocking ERK with the MAPK/ERK kinase (MEK) inhibitor, PD98059, had no effect on this process. Therefore, we concluded that the mocro-opioid receptor, by inducing [Ca(2+)](i) increase, participates in the cumulus-oocyte coupled signaling associated with oocyte maturation.

Animals↗
PubMed2002

[Are we diagnosing people infected with HIV in time?].

OBJECTIVE: To describe the number of AIDS cases who did not know of their HIV infection until they developed AIDS, and the factors relating to this situation. DESIGN: Descriptive study of data of the National AIDS Register.Setting. Spain.Patients. Cases of AIDS in the over-14s diagnosed between 1997 and 1999. RESULTS: Of the 6910 cases of AIDS studied, 35% (n = 2421) knew that they were HIV-positive at the same time as they were diagnosed with AIDS (in the same month or the previous one). The multi-variate analysis showed that this situation occurred less commonly in women (OR = 0.61; 95% CI, 0.53-0.71), in cases diagnosed in prison (OR = 0.19; 95% CI, 0.13-0.27), in cases diagnosed early (OR = 0.49; 95% CI, 0.41-0.60) and among residents in provinces with AIDS rates higher than the Spanish average (OR = 0.88; 95% CI, 0.78-0.99). Ignorance of HIV infection until the AIDS diagnosis was associated to ages of under 25 and over 34, homo/bisexual transmission (OR = 3.20; 95% CI, 2.69-3.80) and heterosexual transmission (OR = 4.88; 95% CI, 4.21-5.65) compared with intravenous drug users, and to the person coming from countries other than Spain, both developed (OR = 2.78; 95% CI, 1.89-4.08) and under-developed (OR = 1.85; 95% CI, 1.26-2.72) countries. CONCLUSIONS: A considerable number of people diagnosed with AIDS were unaware of their HIV infection, especially among people who had never injected drugs. HIV needs to be diagnosed earlier so as to improve prevention and treatments.

Adolescent↗
PubMed2001

Appropriateness of antibiotic prescriptions in community-acquired acute pediatric respiratory infections in Spanish emergency rooms.

OBJECTIVE: To describe the variability and appropriateness of antibiotic prescriptions in community-acquired acute respiratory infections (ARI) during childhood in Spain. METHODS: A descriptive, multicenter study of variability in clinical practice was conducted by evaluating a prospective series of pediatric patients attending the emergency rooms of 11 Spanish hospitals and diagnosed with community-acquired ARI. The appropriateness of the antibiotic prescriptions was assessed by comparing our clinical practice with consensus guidelines developed for this study. RESULTS: We collected data from 6,249 ARI emergencies studied on 30 separate days. Antibiotics were prescribed in 58.7% of the ARI (bronchiolitis, 11.5%; bronchitis, 40.2%; pharyngotonsillitis, 80.9%; nonspecified ARI, 34.8%; pneumonia, 92.4%; otitis, 93.4%; sinusitis, 92.6%). The most commonly used antibiotics were amoxicillin/clavulanate (33.2%), amoxicillin (30.2%), cefuroxime axetil (8.5%) and azithromycin (6%). According to the consensus guidelines developed for this study, therapy was considered to be appropriate in 63.1% of the ARI (first choice, 52.1%; alternative choice, 11.0%) and inappropriate in 36.9%. The percentages of inappropriate prescription according to ARI groups were: bronchiolitis, 11.5%; bronchitis, 31.5%; pharyngotonsillitis, 54.8%; nonspecified ARI, 34.7%; pneumonia, 13.9%; otitis, 25.6%; and sinusitis, 22.2%. CONCLUSIONS: There is excessive use of antibiotics in acute respiratory infections that are presumably viral in origin. An important number of ARI of potentially bacterial origin are treated with antibiotics that are not sufficiently efficacious or that have a broader spectrum than necessary.

Acute Disease↗
PubMed2001

Naloxone inhibits A6 cell Na(+)/H(+) exchange by activating protein kinase C via the mobilization of intracellular calcium.

The opioid receptor antagonist, naloxone, has been shown to have beneficial effects in the kidney and to be implicated in renal salt and water balance. In the present study the signal transduction pathways utilized by naloxone were studied in an epithelial cell line model of the cortical collecting duct, A6 cells. We found that naloxone has a dual effect depending on the concentration used: at a low concentration (10(-6) M) it antagonized the beta-endorphin-dependent increase in cytoplasmic calcium [Ca(2+)](i), while at higher concentrations (>10(-5) M) it increased [Ca(2+)](i) and intracellular inositol phosphate levels. While naloxone-induced increases in [Ca(2+)](i) occurred in the absence of external calcium, it was significantly stimulated by increasing the external calcium concentration, suggesting that naloxone increases [Ca(2+)](i) via both calcium release and calcium influx. In polarized A6 cell monolayers naloxone inhibited the activity of the Na(+)/H(+) exchanger (NHE) only when added to the basolateral cell surface. This inhibition of the NHE was prevented by pretreatment of the cells with either the intracellular calcium chelator, BAPTA or with the protein kinase C inhibitor, calphostin C. These findings demonstrate that naloxone induces a rapid increase in intracellular calcium which inhibits the NHE via the calcium-dependent protein kinase C regulatory pathway.

Animals↗