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1.
Science ; 381(6664): 1345-1350, 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37733841

RESUMO

An estimated 23 million people live on floodplains affected by potentially dangerous concentrations of toxic waste derived from past and present metal mining activity. We analyzed the global dimensions of this hazard, particularly in regard to lead, zinc, copper, and arsenic, using a georeferenced global database detailing all known metal mining sites and intact and failed tailings storage facilities. We then used process-based and empirically tested modeling to produce a global assessment of metal mining contamination in river systems and the numbers of human populations and livestock exposed. Worldwide, metal mines affect 479,200 kilometers of river channels and 164,000 square kilometers of floodplains. The number of people exposed to contamination sourced from long-term discharge of mining waste into rivers is almost 50 times greater than the number directly affected by tailings dam failures.

2.
Sci Rep ; 12(1): 21073, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36473891

RESUMO

Silicone breast implants (SBIs) have been subject to scientific scrutiny since the 1960's because of their potential link with systemic disease symptoms. Breast implant illness (BII) is a cluster of over 56 (systemic) symptoms attributed by patients to their SBIs. BII remains an unofficial medical diagnosis, although its symptoms include but are not limited to the clinical manifestations of autoimmune/inflammatory syndrome induced by adjuvants (ASIA). The aim of this study was to prospectively analyse the effect of explantation on clinical manifestations of ASIA/BII symptoms, as well as to compare (breast-surgery specific) QoL in patients pre- and postoperatively while recording relevant perioperative/patient data. A prospective cohort study was conducted on 140 patients consulting a single surgeon for explantation of SBIs at a single clinic from 2019 to 2021 via their general practitioner, a medical specialist or self-referral. Of all patients, medical (implant) history, lifestyle factors and biometric data were obtained. Patients filled out a novel ASIA/BII symptom-survey termed the ASIA-scale, three domains of the SF-36 and the augmentation module of the BREAST-Q before and four months after the operation. A total of 109 patients completed both the pre- and postoperative survey with a mean follow-up duration of 205 days. There was a significant decrease in all individual symptom scores as well as ASIA-scale summary scores after explantation (p < .001). All SF-36 subdomains showed significant improvement postoperatively (p < .001). The BREAST-Q subdomain 'satisfaction with breasts' improved significantly after explantation (p = .036). No statistically significant association was found between any clinical parameters (such as age, capsulectomy, rupture etc.) and the recovery of symptom scores. This is the largest prospective cohort study on SBI explantation to date showing significant improvement of the most common systemic complaints in SBI patients as well as improvement of satisfaction with breasts and overall quality of life.


Assuntos
Implantes de Mama , Humanos , Implantes de Mama/efeitos adversos , Qualidade de Vida , Estudos Prospectivos
3.
Biol Psychol ; 165: 108171, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34411620

RESUMO

Interoception, perception of one's bodily state, has been associated with mental health and socio-emotional processes. However, several interoception tasks are of questionable validity, meaning associations between interoception and other variables require confirmation with new measures. Here we describe the novel, smartphone-based Phase Adjustment Task (PAT). Tones are presented at the participant's heart rate, but out of phase with heartbeats. Participants adjust the phase relationship between tones and heartbeats until they are synchronous. Data from 124 participants indicates variance in performance across participants which is not affected by physiological or strategic confounds. Associations between interoception and anxiety, depression and stress were not significant. Weak associations between interoception and mental health variables may be a consequence of testing a non-clinical sample. A second study revealed PAT performance to be moderately stable over one week, consistent with state effects on interoception.


Assuntos
Interocepção , Ansiedade , Transtornos de Ansiedade , Emoções , Frequência Cardíaca , Humanos
4.
Oncogene ; 36(15): 2184-2190, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27721413

RESUMO

Hydrocarbon-stapled peptides that display key residues of the p53 transactivation domain have emerged as bona fide clinical candidates for reactivating the tumor suppression function of p53 in cancer by dual targeting of the negative regulators HDM2 and HDMX. A recent study questioned the mechanistic specificity of such stapled peptides based on interrogating their capacity to disrupt p53/HDM2 and p53/HDMX complexes in living cells using a new recombinase enhanced bimolecular luciferase complementation platform (ReBiL). Here, we directly evaluate the cellular uptake, intracellular targeting selectivity and p53-dependent cytotoxicity of the clinical prototype ATSP-7041. We find that under standard serum-containing tissue culture conditions, ATSP-7041 achieves intracellular access without membrane disruption, dose-dependently dissociates both p53/HDM2 and p53/HDMX complexes but not an unrelated protein complex in long-term ReBiL experiments, and is selectively cytotoxic to cancer cells bearing wild-type p53 by inducing a surge in p53 protein level. These studies underscore the importance of a thorough stepwise approach, including consideration of the time-dependence of cellular uptake and intracellular distribution, in evaluating and advancing stapled peptides for clinical translation.


Assuntos
Proteínas Nucleares/metabolismo , Peptídeos Cíclicos/farmacologia , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/metabolismo , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Humanos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/metabolismo , Peptídeos Cíclicos/farmacocinética , Ligação Proteica/efeitos dos fármacos
5.
Neuropsychologia ; 82: 142-148, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26801227

RESUMO

Alexithymia is a subclinical condition characterized by impaired awareness of one's emotional states, which has profound effects on mental health and social interaction. Despite the clinical significance of this condition, the neurocognitive impairment(s) that lead to alexithymia remain unclear. Recent theoretical models suggest that impaired anterior insula (AI) functioning might be involved in alexithymia, but conclusive evidence for this hypothesis is lacking. We measured alexithymia levels in a large sample of brain-injured patients (N=129) and non-brain-injured control participants (N=33), to determine whether alexithymia can be acquired after pronounced damage to the AI. Alexithymia levels were first analysed as a function of group, with patients separated into four groups based on AI damage: patients with >15% damage to AI, patients with <15% damage to AI, patients with no damage to AI, and healthy controls. An ANOVA revealed that alexithymia levels varied across groups (p=0.009), with >15% AI damage causing higher alexithymia relative to all other groups (all p<0.01). Next, a multiple linear regression model was fit with the degree of damage to AI, the degree of damage to a related region (the anterior cingulate cortex, ACC), and the degree of damage to the whole brain as predictor variables, and alexithymia as the dependent variable. Critically, increased AI damage predicted increased alexithymia after controlling for the other two regressors (ACC damage; total lesion volume). Collectively, our results suggest that pronounced AI damage causes increased levels of alexithymia, providing critical evidence that this region supports emotional awareness.


Assuntos
Sintomas Afetivos/etiologia , Sintomas Afetivos/patologia , Lesões Encefálicas/complicações , Córtex Cerebral/patologia , Idoso , Córtex Cerebral/lesões , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Veteranos/psicologia , Guerra do Vietnã
6.
Oncogene ; 35(3): 290-300, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25893296

RESUMO

The limitations of cancer cell lines have led to the development of direct patient-derived xenograft models. However, the interplay between the implanted human cancer cells and recruited mouse stromal and immune cells alters the tumor microenvironment and limits the value of these models. To overcome these constraints, we have developed a technique to expand human hematopoietic stem and progenitor cells (HSPCs) and use them to reconstitute the radiation-depleted bone marrow of a NOD/SCID/IL2rg(-/-) (NSG) mouse on which a patient's tumor is then transplanted (XactMice). The human HSPCs produce immune cells that home into the tumor and help replicate its natural microenvironment. Despite previous passage on nude mice, the expression of epithelial, stromal and immune genes in XactMice tumors aligns more closely to that of the patient tumor than to those grown in non-humanized mice-an effect partially facilitated by human cytokines expressed by both the HSPC progeny and the tumor cells. The human immune and stromal cells produced in the XactMice can help recapitulate the microenvironment of an implanted xenograft, reverse the initial genetic drift seen after passage on non-humanized mice and provide a more accurate tumor model to guide patient treatment.


Assuntos
Neoplasias de Cabeça e Pescoço/genética , Células-Tronco Hematopoéticas/patologia , Microambiente Tumoral/genética , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Medula Óssea/patologia , Linhagem Celular Tumoral , Citocinas/biossíntese , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Camundongos
8.
Leukemia ; 28(9): 1819-27, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24552990

RESUMO

Treatment resistance in T-cell acute lymphoblastic leukemia (T-ALL) is associated with phosphatase and tensin homolog (PTEN) deletions and resultant phosphatidylinositol 3'-kinase (PI3K)-AKT pathway activation, as well as MYC overexpression, and these pathways repress mitochondrial apoptosis in established T-lymphoblasts through poorly defined mechanisms. Normal T-cell progenitors are hypersensitive to mitochondrial apoptosis, a phenotype that is dependent on the expression of proapoptotic BIM. In a conditional zebrafish model, MYC downregulation induced BIM expression in T-lymphoblasts, an effect that was blunted by expression of constitutively active AKT. In human T-ALL cell lines and treatment-resistant patient samples, treatment with MYC or PI3K-AKT pathway inhibitors each induced BIM upregulation and apoptosis, indicating that BIM is repressed downstream of MYC and PI3K-AKT in high-risk T-ALL. Restoring BIM function in human T-ALL cells using a stapled peptide mimetic of the BIM BH3 domain had therapeutic activity, indicating that BIM repression is required for T-ALL viability. In the zebrafish model, where MYC downregulation induces T-ALL regression via mitochondrial apoptosis, T-ALL persisted despite MYC downregulation in 10% of bim wild-type zebrafish, 18% of bim heterozygotes and in 33% of bim homozygous mutants (P=0.017). We conclude that downregulation of BIM represents a key survival signal downstream of oncogenic MYC and PI3K-AKT signaling in treatment-resistant T-ALL.


Assuntos
Proteínas Reguladoras de Apoptose/fisiologia , Proteínas de Membrana/fisiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Proteínas Proto-Oncogênicas c-akt/fisiologia , Proteínas Proto-Oncogênicas c-myc/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Proteína 11 Semelhante a Bcl-2 , Linhagem Celular Tumoral , Humanos , Imidazóis/uso terapêutico , Proteínas de Membrana/antagonistas & inibidores , MicroRNAs/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Quinolinas/uso terapêutico , Transdução de Sinais/fisiologia , Peixe-Zebra
9.
Environ Int ; 60: 56-70, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24013020

RESUMO

Internationally publicized impacts upon human health associated with potentially harmful element (PHE) exposure have been reported amongst internally displaced populations (IDPs) in Mitrovica, Kosovo, following the Kosovan War. Particular concern has surrounded the exposure to Pb indicated by the presence of highly elevated concentrations of Pb in blood and hair samples. This study utilizes a physiologically-based in-vitro extraction method to assess the bioaccessibility of PHEs in surface soils and metallurgical waste in Mitrovica and assesses the potential daily intake of soil-bound PHEs. Maximum As (210mgkg(-1)), Cd (38mgkg(-1)), Cu (410mgkg(-1)), Pb (18790mgkg(-1)) and Zn (8500mgkg(-1)) concentrations in surface soils (0-10cm) are elevated above guideline values. Samples with high PHE concentrations (e.g. As >1000mgkg(-1); Pb >1500mgkg(-1)) exhibit a wide range of bioaccessibilities (5.40 - 92.20% in the gastric (G) phase and 10.00 - 55.80% in the gastric-intestinal (G-I) phase). Samples associated with lower bioaccessibilities typically contain a number of XRD-identifiable primary and secondary mineral phases, particularly As- and Pb-bearing arsenian pyrite, beudantite, galena and cerrusite. Quantification of the potential human exposure risk associated with the ingestion of soil-associated PHEs indicates that on average, 0.01µg Cd kg(-1) BW d(-1), 0.16µg Cu kg(-1) BW d(--1), 0.12µg As kg(-1) BW d(-1), 7.81µg Pb kg(-1) BW d(-1), and 2.68µg Zn kg(-1) BW d(-1) could be bioaccessible following ingestion of PHE-rich soils in the Mitrovica region, with Pb, and to a lesser extent As, indicating the likely possibility of local populations exceeding the recommended tolerable daily intake. Lead present within surface soils of the area could indeed have contributed to the human Pb burden due to the high bioaccessibility of Pb present within these soils (13.40 - 92.20% in the gastric phase). Data for Pb levels in scalp hair (≤120µgg(-1)) and blood (≥650µgdL(-1); WHO, 2004) for children that have lived within IDP camps in Mitrovica indicate significant Pb uptake has indeed taken place. The highly bioaccessible nature of soil-associated PHEs in this study highlights the need for appropriate environmental management approaches that limit the exposure of local populations to these contaminated soils.


Assuntos
Monitoramento Ambiental/métodos , Cabelo/química , Chumbo/análise , Metalurgia , Poluentes do Solo/análise , Solo/química , Resíduos/análise , Disponibilidade Biológica , Criança , Poluição Ambiental/análise , Humanos , Secreções Intestinais/química , Kosovo , Chumbo/farmacocinética , Metais/análise , Metais/farmacocinética , Minerais/análise , Minerais/farmacocinética , Saliva/química , Poluentes do Solo/farmacocinética
10.
Transl Psychiatry ; 3: e285, 2013 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-23880881

RESUMO

It is widely accepted that autism is associated with disordered emotion processing and, in particular, with deficits of emotional reciprocity such as impaired emotion recognition and reduced empathy. However, a close examination of the literature reveals wide heterogeneity within the autistic population with respect to emotional competence. Here we argue that, where observed, emotional impairments are due to alexithymia-a condition that frequently co-occurs with autism-rather than a feature of autism per se. Alexithymia is a condition characterized by a reduced ability to identify and describe one's own emotion, but which results in reduced empathy and an impaired ability to recognize the emotions of others. We briefly review studies of emotion processing in alexithymia, and in autism, before describing a recent series of studies directly testing this 'alexithymia hypothesis'. If found to be correct, the alexithymia hypothesis has wide-reaching implications for the study of autism, and how we might best support subgroups of autistic individuals with, and without, accompanying alexithymia. Finally, we note the presence of elevated rates of alexithymia, and inconsistent reports of emotional impairments, in eating disorders, schizophrenia, substance abuse, Parkinson's Disease, multiple sclerosis and anxiety disorders. We speculate that examining the contribution of alexithymia to the emotional symptoms of these disorders may bear fruit in the same way that it is starting to do in autism.


Assuntos
Sintomas Afetivos/complicações , Transtorno Autístico/complicações , Sintomas Afetivos/psicologia , Transtorno Autístico/psicologia , Inteligência Emocional , Emoções , Empatia , Humanos , Modelos Psicológicos
11.
Br J Anaesth ; 108(3): 452-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22298243

RESUMO

BACKGROUND: Long-held assumptions of poor prognoses for patients with haematological malignancies (HM) have meant that clinicians have been reluctant to admit them to the intensive care unit (ICU). We aimed to evaluate ICU, in-hospital, and 6 month mortality and to identify predictors for in-hospital mortality. METHODS: A cohort study in a specialist cancer ICU of adult HM patients admitted over 5 yr. Data acquired included: patient characteristics, haematological diagnosis, haematopoietic stem cell transplant (HSCT), reason for ICU admission, and APACHE II scores. Laboratory values, organ failures, and level of organ support were recorded on ICU admission. Predictors for in-hospital mortality were evaluated using uni- and multivariate analysis. RESULTS: Of 199 patients, median age was 58 yr [inter-quartile range (IQR) 46-66], 51.7% were emergency admissions, 42.2% post-HSCT, 51.9% required mechanical ventilation, median APACHE II was 21 (IQR 16-25), and median organ failure numbered 2 (IQR 1-4). ICU, in-hospital, and 6 month mortalities were 33.7%, 45.7%, and 59.3%, respectively. Univariate analysis revealed bilirubin >32 µmol litre(-1), mechanical ventilation, ≥2 organ failures, renal replacement therapy, vasopressor support (all P<0.001), graft-vs-host disease (P=0.007), APACHE II score (P=0.02), platelets ≤20×10(9) litre(-1) (P=0.03), and proven invasive fungal infection (P=0.04) were associated with in-hospital mortality. Multivariate analysis revealed that ≥2 organ failures [odds ratio (OR) 5.62; 95% confidence interval (95% CI), 2.30-13.70] and mechanical ventilation (OR 3.03; 95% CI, 1.33-6.90) were independently associated with in-hospital mortality. CONCLUSIONS: Mortality was lower than in previous studies. Mechanical ventilation and ≥2 organ failures were independently associated with in-hospital mortality. 'Traditional' variables such as neutropenia, transplantation status, and APACHE II score no longer appear to be predictive.


Assuntos
Neoplasias Hematológicas/terapia , Unidades de Terapia Intensiva , Serviço Hospitalar de Oncologia , Idoso , Inglaterra/epidemiologia , Feminino , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/diagnóstico , Neoplasias Hematológicas/mortalidade , Transplante de Células-Tronco Hematopoéticas , Mortalidade Hospitalar , Hospitalização , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Prognóstico , Respiração Artificial , Índice de Gravidade de Doença , Condicionamento Pré-Transplante/métodos , Resultado do Tratamento
12.
Clin Res Hepatol Gastroenterol ; 35(1): 55-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20833490

RESUMO

Primary peritoneal mesothelioma is a rare and aggressive tumour. We present six consecutive cases treated by our institution in the last three years. All were between 56-65 years old and only one gave a history of direct contact with asbestos. Four of the patients showed a thrombocytosis on presentation but other blood tests and evaluation of ascitic fluid were normal. In all cases, the diagnosis was made through investigation of mixed abdominal symptoms with CT scanning and laparoscopic biopsy. Despite the use of modern chemotherapy, response to treatment was unpredictable, with survival from ten weeks to three years.


Assuntos
Mesotelioma , Neoplasias Peritoneais , Idoso , Evolução Fatal , Feminino , Humanos , Masculino , Mesotelioma/diagnóstico , Mesotelioma/terapia , Pessoa de Meia-Idade , Neoplasias Peritoneais/diagnóstico , Neoplasias Peritoneais/terapia
14.
Paediatr Anaesth ; 17(3): 289-94, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17263748

RESUMO

BACKGROUND: Pediatric scoliosis surgery may require single lung ventilation for surgical access. Current methods of lung isolation are inadequate for some or all of these children. The Arndt endobronchial blocker (EBB) has been described for use in pediatric thoracic surgery to enable single lung ventilation (SLV). There are few data on its use in pediatric spinal deformity surgery. We report the successful use of the Arndt EBB in a series of these patients. METHODS: Any patient undergoing surgical correction of scoliosis involving a lateral thoracotomy for an anterior approach was managed with an Arndt EBB (5, 7 and 9 Fr gauge) to facilitate SLV. All cases were undertaken by a pediatric anesthetist trained in pediatric bronchoscopy; a 2.2 or 2.8 mm pediatric fiberoptic scope was used for placement and positional confirmation. RESULTS: Patients' ages and weights ranged from 18 months to 18 years, and from 9.4 to 71 kg. All had idiopathic or congenital scoliosis; one underwent a vertical expansion prosthetic titanium rib (VEPTR) procedure. In all 20 patients, placement was easily and quickly achieved with no incorrect placements. There was one displacement after inflation, quickly corrected. Right upper lobe deflation proved difficult in one patient with high take-off of the right upper lobe bronchus. The surgical field was excellent in all cases. CONCLUSIONS: In our case series, Arndt EBB provided a safe and highly effective means of single lung isolation for children undergoing pediatric scoliosis surgery.


Assuntos
Intubação Intratraqueal/instrumentação , Escoliose/cirurgia , Adolescente , Anestesia Geral , Criança , Pré-Escolar , Desenho de Equipamento , Humanos , Lactente , Intubação Intratraqueal/efeitos adversos , Intubação Intratraqueal/métodos
15.
J Phys Chem B ; 110(3): 1301-8, 2006 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-16471678

RESUMO

The effect of molecular chirality on electron transmission is explored by photoelectrochemistry. Thiol-terminated chiral scaffold molecules containing a porphyrin chromophore were self-assembled on gold surfaces to form a monolayer. Incorporation of the SAM-coated gold into an electrochemical cell and illumination with visible light generated a cathodic photocurrent. When using circularly polarized light, the photocurrent displayed an asymmetry (different magnitude of photocurrent for right versus left polarization) that changed with the molecular chirality (left- or right-handedness of the scaffold). A symmetry constraint on the electronic coupling between the porphyrin and the organic scaffold is proposed as a possible mechanism for the photocurrent asymmetry.

16.
Brain ; 128(Pt 7): 1571-83, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15817510

RESUMO

In this study, we describe a new form of synaesthesia in which visual perception of touch elicits conscious tactile experiences in the perceiver. We describe a female subject (C) for whom the observation of another person being touched is experienced as tactile stimulation on the equivalent part of C's own body. Apart from this clearly abnormal synesthetic experience, C is healthy and normal in every other way. In this study, we investigate whether C's 'mirrored touch' synesthetic experience is caused by overactivity in the neural system that responds to the observation of touch. A functional MRI experiment was designed to investigate the neural system involved in the perception of touch in a group of 12 non-synesthetic control subjects and in C. We investigated neural activity to the observation of touch to a human face or neck compared with the observation of touch to equivalent regions on an object. Furthermore, to investigate the somatosensory topography of the activations during observation of touch, we compared activations when observing a human face or neck being touched with activations when the subjects themselves were touched on their own face or neck. The results demonstrated that the somatosensory cortex was activated in the non-synesthetic subjects by the mere observation of touch and that this activation was somatotopically organized such that observation of touch to the face activated the head area of primary somatosensory cortex, whereas observation of touch to the neck did not. Moreover, in non-synesthetic subjects, the brain's mirror system-comprising premotor cortex, superior temporal sulcus and parietal cortex-was activated by the observation of touch to another human more than to an object. C's activation patterns differed in three ways from those of the non-synesthetic controls. First, activations in the somatosensory cortex were significantly higher in C when she observed touch. Secondly, an area in left premotor cortex was activated in C to a greater extent than in the non-synesthetic group. Thirdly, the anterior insula cortex bilaterally was activated in C, but there was no evidence of such activation in the non-synesthetic group. The results suggest that, in C, the mirror system for touch is overactive, above the threshold for conscious tactile perception.


Assuntos
Transtornos da Percepção/fisiopatologia , Córtex Somatossensorial/fisiopatologia , Distúrbios Somatossensoriais/fisiopatologia , Tato , Percepção Visual , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Psicofísica , Córtex Somatossensorial/fisiologia , Gravação em Vídeo
17.
Neuroreport ; 12(18): 4061-4, 2001 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-11742238

RESUMO

This study determined the effects of glutamate uptake inhibition on primary-afferent excitatory postsynaptic potentials (DR-EPSPs) in spinal dorsal horn neurones in vitro from naive rats and rats with localised arthritis. The glutamate uptake inhibitor L-PDC (1 mM) significantly reduced DR-EPSP amplitude and duration with a greater reduction in arthritic than in naive rats. The group II/III selective metabotropic glutamate receptor antagonist CPPG (100 microM) reversed L-PDC-induced DR-EPSP inhibition in naive but not arthritic rats. L-AP4 (30 microM), a group III metabotropic agonist, inhibited DR-EPSPs with no difference between naive and arthritic rats. These data suggest the existence of an autoregulatory feedback mechanism that limits spinal postsynaptic excitation especially during inflammation. The putative contribution of metabotropic glutamate receptors to this phenomenon is discussed.


Assuntos
Sistema X-AG de Transporte de Aminoácidos/metabolismo , Artrite Experimental/metabolismo , Glicina/análogos & derivados , Células do Corno Posterior/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Sistema X-AG de Transporte de Aminoácidos/antagonistas & inibidores , Animais , Ácidos Dicarboxílicos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Retroalimentação Fisiológica/fisiologia , Ácido Glutâmico/metabolismo , Glicina/farmacologia , Técnicas In Vitro , Inibidores da Captação de Neurotransmissores/farmacologia , Propionatos/farmacologia , Pirrolidinas/farmacologia , Ratos , Ratos Wistar , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia
18.
Neuropharmacology ; 41(5): 582-91, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11587713

RESUMO

The effect of altered endogenous levels of synaptic glutamate on neurotransmission and synaptic dorsal horn Fos expression was determined in rat spinal cord in vitro. The uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylate (L-PDC, 1mM) was tested against dorsal root-ventral root potentials (DR-VRP), afferent-mediated slow dorsal horn excitatory postsynaptic potentials (DR-EPSP) and nociceptive afferent-induced synaptic currents (EPSCs) of substantia gelatinosa neurones. L-PDC reduced DR-VRP fast and slow peak amplitude and duration (P<0.05), slow DR-EPSP amplitude and duration (P<0.005) and EPSC amplitude (P<0.05). The Group II/III mGluR antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG, 100 microM) reduced L-PDC inhibition of synaptic potentials. The Group II antagonist (2S)-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoic acid (LY341495, 300 nM) and the Group III antagonist (RS)-alpha-methylserine-O-phosphate (MSOP, 10 microM) partially reversed EPSC inhibition by L-PDC. The Group III agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4, 30 microM) mimicked CPPG-sensitive inhibitory effects of L-PDC on DR-VRP (P<0.001) and the slow DR-EPSP (P<0.005). L-PDC (1mM) or L-AP4 (30 microM) reduced afferent-evoked dorsal horn Fos expression, this effect was reversed by CPPG. These data suggest that increased synaptic glutamate levels may activate inhibitory Group II/III mGluR receptors and impact significantly on nociceptive neurotransmission and transcriptional adaptive responses of target neurones.


Assuntos
Vias Aferentes/metabolismo , Ácido Glutâmico/biossíntese , Glicina/análogos & derivados , Inibidores da Captação de Neurotransmissores/farmacologia , Células do Corno Posterior/metabolismo , Proteínas Proto-Oncogênicas c-fos/biossíntese , Vias Aferentes/efeitos dos fármacos , Animais , Ácidos Dicarboxílicos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Genes fos/efeitos dos fármacos , Glicina/farmacologia , Técnicas In Vitro , Células do Corno Posterior/efeitos dos fármacos , Propionatos/farmacologia , Proteínas Proto-Oncogênicas c-fos/genética , Pirrolidinas/farmacologia , Ratos
19.
Proc Natl Acad Sci U S A ; 98(20): 11777-82, 2001 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-11553786

RESUMO

Mammalian Trp proteins are candidates for plasma membrane calcium channels regulated by receptor activation or by intracellular calcium store depletion [capacitative calcium entry (CCE)]. One extensively investigated member of the Trp family, the human Trp3 (hTrp3), behaves as a receptor-activated, calcium-permeable, nonselective cation channel when expressed in cell lines and does not appear to be activated by store depletion. Nonetheless, there is good evidence that Trp3 can be regulated by interacting with inositol trisphosphate receptors (IP(3)Rs), reminiscent of the conformational coupling mode of CCE. To investigate the role of Trp3 in CCE, and its regulation by IP(3)R, we transiently expressed hTrp3 in the wild-type DT40 chicken B lymphocyte cell line and its variant lacking IP(3)R. Expression of hTrp3 in either wild-type or IP(3)R-knockout cells did not increase basal membrane permeability, but resulted in a substantially greater divalent cation entry after thapsigargin-induced store depletion. This hTrp3-dependent divalent cation entry was significantly greater in the wild type than in IP(3)R-knockout cells. Thus, it appears that in this cell line, hTrp3 forms channels that are store-operated by both IP(3)R-dependent and IP(3)R-independent mechanisms. Trp3, or one of its structural relatives, is a candidate for the store-operated, nonselective cation channels observed in smooth muscle cells and other cell types.


Assuntos
Linfócitos B/fisiologia , Canais de Cálcio/fisiologia , Canais Iônicos/fisiologia , Receptores Citoplasmáticos e Nucleares/fisiologia , Animais , Linfócitos B/efeitos dos fármacos , Bário/metabolismo , Cálcio/metabolismo , Canais de Cálcio/genética , Linhagem Celular , Galinhas , Clonagem Molecular , Primers do DNA , Fura-2 , Vetores Genéticos , Humanos , Receptores de Inositol 1,4,5-Trifosfato , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Canais de Cátion TRPC , Tapsigargina/farmacologia , Transcrição Gênica , Transfecção
20.
J Cell Sci ; 114(Pt 12): 2223-9, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11493662

RESUMO

Capacitative Ca(2+) entry involves the regulation of plasma membrane Ca(2+) channels by the filling state of intracellular Ca(2+) stores in the endoplasmic reticulum (ER). Several theories have been advanced regarding the mechanism by which the stores communicate with the plasma membrane. One such mechanism, supported by recent findings, is conformational coupling: inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) receptors in the ER may sense the fall in Ca(2+) levels through Ca(2+)-binding sites on their lumenal domains, and convey this conformational information directly by physically interacting with Ca(2+) channels in the plasma membrane. In support of this idea, in some cell types, store-operated channels in excised membrane patches appear to depend on the presence of both Ins(1,4,5)P(3) and Ins(1,4,5)P(3) receptors for activity; in addition, inhibitors of Ins(1,4,5)P(3) production that either block phospholipase C or inhibit phosphatidylinositol 4-kinase can block capacitative Ca(2+) entry. However, the electrophysiological current underlying capacitative Ca(2+) entry is not blocked by an Ins(1,4,5)P(3) receptor antagonist, and the blocking effects of a phospholipase C inhibitor are not reversed by the intracellular application of Ins(1,4,5)P(3). Furthermore, cells whose Ins(1,4,5)P(3) receptor genes have been disrupted can nevertheless maintain their capability to activate capacitative Ca(2+) entry channels in response to store depletion. A tentative conclusion is that multiple mechanisms for signaling capacitative Ca(2+) entry may exist, and involve conformational coupling in some cell types and perhaps a diffusible signal in others.


Assuntos
Canais de Cálcio/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Ativação do Canal Iônico , Animais , Condutividade Elétrica , Retículo Endoplasmático/metabolismo , Exocitose , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Receptores de Inositol 1,4,5-Trifosfato , Modelos Biológicos , Receptores Citoplasmáticos e Nucleares/metabolismo
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