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1.
Br J Dermatol ; 179(4): 951-958, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29729180

RESUMO

BACKGROUND: Carriage rates of Staphylococcus aureus on affected skin in atopic dermatitis (AD) are approximately 70%. Increasing disease severity during flares and overall disease severity correlate with increased burden of S. aureus. Treatment in AD therefore often targets S. aureus with topical and systemic antimicrobials. OBJECTIVES: To determine whether antimicrobial sensitivities and genetic determinants of resistance differed in S. aureus isolates from the skin of children with AD and healthy child nasal carriers. METHODS: In this case-control study, we compared S. aureus isolates from children with AD (n = 50) attending a hospital dermatology department against nasal carriage isolates from children without skin disease (n = 49) attending a hospital emergency department for noninfective conditions. Using whole genome sequencing we generated a phylogenetic framework for the isolates based on variation in the core genome, then compared antimicrobial resistance phenotypes and genotypes between disease groups. RESULTS: Staphylococcus aureus from cases and controls had on average similar numbers of phenotypic resistances per isolate. Case isolates differed in their resistance patterns, with fusidic acid resistance (FusR ) being significantly more frequent in AD (P = 0·009). The genetic basis of FusR also differentiated the populations, with chromosomal mutations in fusA predominating in AD (P = 0·049). Analysis revealed that FusR evolved multiple times and via multiple mechanism in the population. Carriage of plasmid-derived qac genes, which have been associated with reduced susceptibility to antiseptics, was eight times more frequent in AD (P = 0·016). CONCLUSIONS: The results suggest that strong selective pressure drives the emergence and maintenance of specific resistances in AD.


Assuntos
Anti-Infecciosos Locais/efeitos adversos , Dermatite Atópica/microbiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Infecções Cutâneas Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia , Administração Cutânea , Anti-Infecciosos Locais/administração & dosagem , Portador Sadio/diagnóstico , Portador Sadio/tratamento farmacológico , Portador Sadio/microbiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Dermatite Atópica/diagnóstico , Dermatite Atópica/tratamento farmacológico , Farmacorresistência Bacteriana/genética , Feminino , Voluntários Saudáveis , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Mutação , Mucosa Nasal/microbiologia , Fator G para Elongação de Peptídeos/genética , Fator G para Elongação de Peptídeos/isolamento & purificação , Índice de Gravidade de Doença , Pele/microbiologia , Infecções Cutâneas Estafilocócicas/diagnóstico , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/isolamento & purificação
2.
J Hosp Infect ; 109: 1-9, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33181280

RESUMO

Outbreaks pose a significant risk to patient safety as well as being costly and time consuming to investigate. The implementation of targeted infection prevention and control measures relies on infection prevention and control teams having access to rapid results that detect resistance accurately, and typing results that give clinically useful information on the relatedness of isolates. At present, determining whether transmission has occurred can be a major challenge. Conventional typing results do not always have sufficient granularity or robustness to define strains unequivocally, and sufficient epidemiological data are not always available to establish links between patients and the environment. Whole-genome sequencing (WGS) has emerged as the ultimate genotyping tool, but has not yet fully crossed the divide between research method and routine clinical diagnostic microbiological technique. A clinical WGS service was officially established in 2014 as part of the Scottish Healthcare Associated Infection Prevention Institute to confirm or refute outbreaks in hospital settings from across Scotland. This article describes the authors' experiences with the aim of providing new insights into practical application of the use of WGS to investigate healthcare and public health outbreaks. Solutions to overcome barriers to implementation of this technology in a clinical environment are proposed.


Assuntos
Surtos de Doenças , Saúde Pública , Sequenciamento Completo do Genoma , Atenção à Saúde , Genoma Bacteriano , Técnicas de Genotipagem , Humanos , Escócia
3.
Diabet Med ; 27(6): 624-30, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20546278

RESUMO

AIMS: Diabetic nephropathy is a leading cause of end-stage renal disease. The transforming growth factor beta-bone morphogenic protein (BMP) pathway is implicated in the pathogenesis of diabetic nephropathy. The BMP2, BMP4 and BMP7 genes are located near linkage peaks for renal dysfunction, and we hypothesize that genetic polymorphisms in these biological and positional candidate genes may be risk factors for diabetic kidney disease. METHODS: The BMP7 gene was screened, variants identified and allele frequencies determined by bidirectionally sequencing 46 individuals to facilitate selection of tag SNPs (n = 4). For BMP2 and BMP4 genes, data were downloaded for 19 single nucleotide polymorphisms (SNPs) from the International HapMap project and six tag SNPs selected. RESULTS: The BMP7 gene was screened for novel genetic polymorphisms, haplotypes were identified, an appropriate subset of variants selected for the investigation of common genetic risk factors, and BMP2, BMP4 and BMP7 genes assessed for association with diabetic nephropathy in 1808 individuals. Thirty-two SNPs were identified, of which 11 were novel, including an amino-acid changing SNP (+63639C>T). No significant differences (P > 0.2) were observed when comparing genotype or allele or haplotype frequencies between 864 individuals with Type 1 diabetes and nephropathy compared with 944 individuals with Type 1 diabetes without nephropathy, stratified by recruitment centre. CONCLUSIONS: Common polymorphisms in these BMP genes do not strongly influence genetic susceptibility to diabetic nephropathy in White individuals with Type 1 diabetes mellitus.


Assuntos
Proteínas Morfogenéticas Ósseas/genética , Diabetes Mellitus Tipo 1/genética , Nefropatias Diabéticas/genética , Falência Renal Crônica/genética , Adulto , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 7/genética , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único
4.
Diabetologia ; 52(5): 844-9, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19247629

RESUMO

AIMS/HYPOTHESIS: SMAD proteins are involved in multiple signalling pathways and are key modulators of gene expression. We hypothesised that genetic variation in selected SMAD genes contributes to susceptibility to diabetic nephropathy. METHODS: We selected 13 haplotype tag (ht) single nucleotide polymorphisms (SNPs) from 67 variants identified by resequencing the SMAD2 and SMAD3 genes. For SMAD1, SMAD4 and SMAD5 genes, genotype data were downloaded for 217 SNPs from Phase II of the International HapMap project. Of these, 85 SNPs met our inclusion criteria, resulting in the selection of 13 tag SNPs for further investigation. A case-control approach was employed, using 267 nephropathic patients and 442 controls with type 1 diabetes from Ireland. Two further populations (totalling 1,407 patients, 2,238 controls) were genotyped to validate initial findings. Genotyping was conducted using iPLEX, TaqMan and gel electrophoresis. RESULTS: The distribution of genotypes was in Hardy-Weinberg equilibrium. Analysis by the chi(2) test of genotype and allele frequencies in patients versus controls in the Irish population (n = 709) revealed evidence for the association of one allele at 5% level of significance (rs10515478, p(uncorrected) = 0.006; p(corrected) = 0.04). This finding represents a relatively small difference in allele frequency of 6.4% in the patient group compared with 10.7% in the control group; this difference was not supported in subsequent investigations using DNA from European individuals with similar phenotypic characteristics. CONCLUSIONS/INTERPRETATION: We selected an appropriate subset of variants for the investigation of common genetic risk factors and assessed SMAD1 to SMAD5 genes for association with diabetic nephropathy. We conclude that common polymorphisms in these genes do not strongly influence genetic susceptibility to diabetic nephropathy in white individuals with type 1 diabetes mellitus.


Assuntos
Diabetes Mellitus Tipo 1/genética , Nefropatias Diabéticas/genética , Predisposição Genética para Doença , Polimorfismo Genético , Polimorfismo de Nucleotídeo Único , Proteínas Smad/genética , Adolescente , Pressão Sanguínea , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/fisiopatologia , Nefropatias Diabéticas/fisiopatologia , Genótipo , Hemoglobinas Glicadas/metabolismo , Humanos , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/genética , Pessoa de Meia-Idade , Proteína Smad1/genética , Proteína Smad4/genética , Proteína Smad5/genética
5.
Science ; 207(4426): 84-6, 1980 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-7350645

RESUMO

Cerebrovascular permeability of four modified opioid peptides--[D-Ala2]methionine enkephalin amide, beta-[D-Ala62,14C-Homoarg69]lipotropin 61 -69, alpha-[D-Ala2,14C-Homoarg9]endorphin, and beta-[D-Ala2,14C-Homoarg]endorphin--ranged from 1.4 to 3.9 X 10(-6) centimeters per second in brain regions of the conscous rat. These significant permeabilities should allow the peptides to fill the extracellular brain space with a half time of 3 to 11 minutes, as a result of a step increase in plasma concentration of unbound peptide.


Assuntos
Barreira Hematoencefálica , Encéfalo/metabolismo , Endorfinas/metabolismo , beta-Lipotropina/metabolismo , Animais , Permeabilidade Capilar , Encefalinas/metabolismo , Espaço Extracelular/metabolismo , Masculino , Ratos , Solubilidade
6.
Arch Gen Psychiatry ; 36(1): 85-90, 1979 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-216331

RESUMO

Data from all-night EEG sleep studies were used to distinguish normal subjects, primary depressed patients, and primary insomniac patients. In part 1, we compared 41 normal subjects, 56 depressed patients, and 18 insomniacs. In a univariate comparison with normal subjects, depressed patients showed less total sleep, longer sleep latency, more early morning awake time, more intermittent awake time, less delta sleep, less sleep efficiency, and shorter rapid eye movement (REM) latencies; compared with insomniacs, depressed patients showed greater early morning awake time, shorter REM latency, greater REM index, and greater REM density. Using multivariate discriminant analysis, 82% of the sample were correctly classified by diagnosis: 100% of the normal subjects, 72% of the depressed patients, and 77% of the insomniacs. Eight variables contributed to the multivariate separation of depressed individuals from insomniacs and normals: total sleep time, total recording period, sleep efficiency, sleep latency, early morning awake time, awake time, REM time and REM%. When the discriminant functions were applied to a second group of 18 primary depressed patients, 82% were correctly classified as depressed. These results suggest that primary depressed patients and primary insomniac patients may show relatively characteristic patterns of sleep abnormality.


Assuntos
Córtex Cerebral/fisiopatologia , Depressão/diagnóstico , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Adulto , Análise de Variância , Depressão/fisiopatologia , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fases do Sono , Sono REM
7.
Genes Brain Behav ; 14(4): 369-76, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25778778

RESUMO

Twin studies indicate that dyscalculia (or mathematical disability) is caused partly by a genetic component, which is yet to be understood at the molecular level. Recently, a coding variant (rs133885) in the myosin-18B gene was shown to be associated with mathematical abilities with a specific effect among children with dyslexia. This association represents one of the most significant genetic associations reported to date for mathematical abilities and the only one reaching genome-wide statistical significance. We conducted a replication study in different cohorts to assess the effect of rs133885 maths-related measures. The study was conducted primarily using the Avon Longitudinal Study of Parents and Children (ALSPAC), (N = 3819). We tested additional cohorts including the York Cohort, the Specific Language Impairment Consortium (SLIC) cohort and the Raine Cohort, and stratified them for a definition of dyslexia whenever possible. We did not observe any associations between rs133885 in myosin-18B and mathematical abilities among individuals with dyslexia or in the general population. Our results suggest that the myosin-18B variant is unlikely to be a main factor contributing to mathematical abilities.


Assuntos
Discalculia/genética , Miosinas/genética , Polimorfismo de Nucleotídeo Único , Proteínas Supressoras de Tumor/genética , Adolescente , Estudos de Casos e Controles , Criança , Estudos de Coortes , Feminino , Humanos , Masculino
8.
Hypertension ; 20(4): 501-10, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1398885

RESUMO

Not only blood pressure but also behavioral activity, brain morphology, and cerebral ventricular size differ between young spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. This suggests that cerebral blood flow and cerebral metabolism may vary between these two rat strains. To test this hypothesis, we measured local cerebral glucose utilization in 31 brain areas of 26-30-week-old rats. Local cerebral blood flow was also assessed in these same areas. Cerebral glucose utilization was measured by the 2-deoxyglucose method; cerebral blood flow was determined by the iodoantipyrene method. In virtually all gray matter structures, the apparent rate of glucose utilization was lower in SHR than in normotensive WKY rats; the interstrain differences varied significantly among structures and were statistically significant (uncorrected t tests) in 14 of 28 gray matter areas. Local cerebral blood flow was fairly similar in the two rat strains. The coupling of blood flow to glucose utilization varied significantly among brain areas in normotensive WKY rats as well as in SHR. In a number of gray matter structures, the coupling of flow to metabolism differed between hypertensive and normotensive animals. These data suggest that for many brain areas, either glucose utilization or glucose partitioning differs between WKY rats and SHR.


Assuntos
Encéfalo/metabolismo , Circulação Cerebrovascular , Glucose/metabolismo , Hipertensão/fisiopatologia , Ratos Endogâmicos SHR/fisiologia , Ratos Endogâmicos WKY/fisiologia , Análise de Variância , Animais , Autorradiografia , Comportamento Animal , Pressão Sanguínea , Temperatura Corporal , Peso Corporal , Dióxido de Carbono/sangue , Hematócrito , Masculino , Concentração Osmolar , Oxigênio/sangue , Ratos
9.
Biol Psychiatry ; 34(11): 798-809, 1993 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-8292684

RESUMO

A multiple regression/discriminant analysis of positron emission tomographic cerebral metabolic (rCMRglc) data in 10 obsessive-compulsive disorder (OCD) patients before and during pharmacotherapy was carried out to see if rCMRglc interdependencies distinguished OCD patients from controls. Before therapy, a discriminant function reflecting parietal, sensorimotor, and midbrain rCMRglc interdependencies correctly classified eight (80%) of the 10 patients as OCD; after therapy, six (70%) were classified as controls, most of whom were responders. Before therapy, rCMRglc interdependencies involving basal ganglia, thalamus, limbic, and sensory and association cortical regions distinguished 67% of patients who clinically responded to drug (RESP, n = 6) and 75% of patients who did not (NRESP, n = 4) from controls. After therapy, all RESP were classified as controls; classification of NRESP remained unchanged. The results suggest the conjunctive utility of this method to assess individual differences in rCMRglc during pharmacotherapy, and to explore the neurobiology of OCD.


Assuntos
Encéfalo/metabolismo , Clomipramina/uso terapêutico , Fluoxetina/uso terapêutico , Transtorno Obsessivo-Compulsivo/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Análise Discriminante , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtorno Obsessivo-Compulsivo/tratamento farmacológico , Transtorno Obsessivo-Compulsivo/metabolismo , Análise de Regressão , Fatores de Tempo , Tomografia Computadorizada de Emissão
10.
J Cereb Blood Flow Metab ; 13(3): 475-86, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8478406

RESUMO

The postulation that hypoxia increases local cerebral blood flow (lCBF) mainly by perfusing more capillaries (the capillary recruitment hypothesis) was tested in awake adult male Sprague-Dawley rats exposed to 10% O2 and control rats. The [14C]iodoantipyrine technique was used to measure lCBF. Local cerebral blood volume was determined by measuring plasma and red cell distribution spaces within the brain parenchyma with 125I-labeled serum albumin (RISA) and 55Fe-labeled red cells (RBC), respectively. Tissue radioactivity in 44 brain areas was estimated by quantitative autoradiography. Hypoxia raised lCBF by 25-90% in all brain areas. In about one-quarter of the brain areas, the rise in blood flow was associated with a small increase in microvascular plasma and blood volumes. This change in blood volume, which could be the result of perfusing more parenchymal microvessels and/or increasing parenchymal microvessel diameter, is not sufficient to account for the observed rise in lCBF. In the remaining areas the RISA, RBC, and blood spaces were either unchanged or only marginally increased by hypoxia. For this hypoxic perturbation, the major mechanism of raising blood flow appears to be increased velocity of microvessel perfusion and not perfusion of more capillaries. These findings provide only limited support for the capillary recruitment hypothesis.


Assuntos
Velocidade do Fluxo Sanguíneo , Circulação Cerebrovascular , Hipóxia/fisiopatologia , Animais , Eritrócitos/fisiologia , Hematócrito , Masculino , Microcirculação , Plasma/fisiologia , Ratos , Ratos Sprague-Dawley , Soroalbumina Radioiodada , Fatores de Tempo
11.
J Cereb Blood Flow Metab ; 13(3): 487-97, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8478407

RESUMO

Local cerebral blood flow is lowered in many brain areas of the rat by high-dose pentobarbital (50 mg/kg). In the present study, the mechanism of this flow change was examined by measuring the distribution of radiolabeled red blood cells (RBCs) and albumin (RISA) in small parenchymal microvessels and calculating the microvascular distribution spaces and mean transit times of RBCs, RISA, and blood. In most brain areas, pentobarbital slightly decreased the RISA space, modestly increased the RBC space, and did not alter the blood space. The mean transit times of RBCs, RISA, and blood through the perfused microvessels were considerably greater in treated rats than in controls. These findings indicate that the mechanism by which high-dose pentobarbital diminishes local cerebral blood flow in rat brain is, in the main, a lowered linear velocity of plasma and RBC flow through small parenchymal microvessels and not decreased percentage of perfused capillaries (capillary retirement). This response is probably driven mainly by lowered local metabolism and may well entail a slight increase in the number of small microvessels that are perfused by RBCs.


Assuntos
Velocidade do Fluxo Sanguíneo , Circulação Cerebrovascular/efeitos dos fármacos , Eritrócitos/fisiologia , Pentobarbital/farmacologia , Plasma/fisiologia , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Hematócrito , Masculino , Microcirculação/efeitos dos fármacos , Plasma/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Soroalbumina Radioiodada , Fatores de Tempo
12.
J Cereb Blood Flow Metab ; 10(5): 698-706, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2384542

RESUMO

Blood-brain barrier permeability to four large neutral and one basic amino acid was studied in 30 patients with the double indicator technique. The resultant 64 venous outflow curves were analyzed by means of two models that take tracer backflux and capillary heterogeneity into account. The first model considers the blood-brain barrier as a double membrane where amino acids from plasma enter the endothelial cell. When an endothelial cell volume of 0.001 ml/g was assumed, permeability from the blood into the endothelial cell was, for most amino acids, about 10-20 times larger than the permeability for the reverse direction. The second model assumes that the amino acids, after intracarotid injection, cross a single membrane barrier and enter a well-mixed compartment, the brain extracellular fluid, i.e., the endothelial cell is assumed to behave as a single membrane. With this model, for large neutral amino acids, the permeability out of the extracellular fluid space back to the blood was between 8 to 12 times higher than the permeability from the blood into the brain. Such a difference in permeabilities across the blood-brain barrier can almost entirely be ascribed to the effect of a nonlinear transport system combined with a relatively small brain amino acid metabolism. The significance of the possible presence of an energy-dependent A system at the abluminal side of the blood-brain barrier is discussed and related to the present findings. For both models, calculation of brain extraction by simple peak extraction values underestimates true unidirectional brain uptake by 17-40%. This raises methodological problems when estimating blood to brain transfer of amino acids with this traditional in vivo method.


Assuntos
Aminoácidos/farmacocinética , Barreira Hematoencefálica , Adulto , Arginina/farmacocinética , Transporte Biológico Ativo , Permeabilidade da Membrana Celular , Feminino , Humanos , Leucina/farmacocinética , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Fenilalanina/farmacocinética , Triptofano/farmacocinética , Tirosina/farmacocinética
13.
J Cereb Blood Flow Metab ; 13(5): 748-54, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8360281

RESUMO

Two consecutive measurements of resting CBF were carried out in normal volunteers (n = 25) using H2(15)O positron emission tomography. Absolute whole-brain blood flow (WBBF; ml 100 g-1 min-1, mean +/- SD) for the first (40.3 +/- 6.4) and second (39.3 +/- 6.5) measurements was not significantly different (mean % difference 2.3 +/- 8.7). Analysis of regions of interest showed no significant differences in absolute regional CBF (rCBF) and normalized (rCBF/WBBF) rCBF. Left-right differences were also not significant. These data demonstrate the reproducibility of resting CBF measurements in normal humans.


Assuntos
Circulação Cerebrovascular , Tomografia Computadorizada de Emissão , Água , Adulto , Afeto , Humanos , Masculino , Entrevista Psiquiátrica Padronizada , Radioisótopos de Oxigênio , Valores de Referência , Fluxo Sanguíneo Regional , Reprodutibilidade dos Testes , Descanso
14.
J Cereb Blood Flow Metab ; 9(3): 290-303, 1989 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2541146

RESUMO

A translocase to transport hexose phosphate formed in the cytosol into the cisterns of the endoplasmic reticulum, where the phosphatase resides, is absent in brain (Fishman and Karnovsky, 1986). 2-Deoxyglucose-6-phosphate (DG-6-P) may therefore have limited access to glucose-6-phosphatase (G-6-Pase), and transport of the DG-6-P across the endoplasmic reticular membrane may be rate limiting to its dephosphorylation. To take this compartmentation into account, a five-rate constant (5K) model was developed to describe the kinetic behavior of 2-deoxyglucose (DG) and its phosphorylated product in brain. Loss of DG-6-P was modeled as a two-step process: (a) transfer of DG-6-P from the cytosol into the cisterns of the endoplasmic reticulum; (b) hydrolysis of DG-6-P by G-6-Pase and subsequent return of the free DG to the precursor pool. Local CMRglc (LCMRglc) was calculated in the rat on the basis of this model and compared with values calculated on the basis of the three-rate constant (3K) and the four-rate constant (4K) models of the DG method. The results show that under normal physiological conditions all three models yield values of LCMRglc that are essentially equivalent for experimental periods between 25 and 45 min. Therefore, the simplest model, the 3K model, is sufficient. For experimental periods from 60 to 120 min, the 4K and 5K models do not correct completely for loss of product, but the 5K model does yield estimates of LCMRglc that are closer to the values at 45 min than those obtained with the 3K and 4K models.


Assuntos
Encéfalo/metabolismo , Desoxiaçúcares/metabolismo , Desoxiglucose/metabolismo , Glucose-6-Fosfato/análogos & derivados , Modelos Biológicos , Animais , Encéfalo/ultraestrutura , Radioisótopos de Carbono , Citosol/metabolismo , Retículo Endoplasmático/metabolismo , Glucose-6-Fosfatase/metabolismo , Glucofosfatos/metabolismo , Hidrólise , Cinética , Masculino , Matemática , Ratos , Ratos Endogâmicos
15.
J Cereb Blood Flow Metab ; 10(6): 781-807, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2134838

RESUMO

Radioiodinated R- and S-Quinuclidinyl derivatives of RS-benzilate (R- and S-125IQNB) have been synthesized for quantitative evaluation of muscarinic acetylcholine receptor binding in vivo. Two sets of experiments were performed in rats. The first involved determining the metabolite-corrected blood concentration and tissue distribution of tracer R-IQNB (active enantiomer) and S-IQNB (inactive enantiomer) in brain 1 min to 26 h after intravenous injection. The second involved the measurement of brain tissue washout over a 2-min period after loading the brain by an intracarotid artery injection of the ligands. Various pharmacokinetic models were tested, which included transport across the blood-brain barrier (BBB), nonspecific binding, low-affinity binding, and high-affinity binding. Our analysis demonstrated that the assumptions of rapid equilibrium across the BBB and rapid nonspecific binding are incorrect and result in erroneous estimates of the forward rate constant for binding at the high-affinity receptor sites (k3). The estimated values for influx across the BBB (K1), the steady-state accumulation rate in cerebrum (K), and the dissociation rate constant at the high-affinity site (k4) of R-IQNB were independent of the specific compartmental model used to analyze these data (K1 approximately 0.23 ml/min/g, K approximately 0.13 ml/min/g, and k4 approximately 0.0019 min-1 for caudate). In contrast, the estimated values of k3 and the efflux rate constant (k2) varied over a 10-fold range between different compartmental models (k3 approximately 2.3-22 min-1 and k2 approximately 1.6-16 min-1 in caudate), but their ratios were constant (k3/k2 approximately 1.4). Our analysis demonstrates that the estimates of k3 (and derived values such as the binding potential) are model dependent, that the rate of R-IQNB accumulation in cerebrum depends on transport across the BBB as well as the rate of binding, and that uptake in cerebrum is essentially irreversible during the first 360 min after intravenous administration. Graphical analysis was consistent with compartmental analysis of the data and indicated that steady-state uptake of R-IQNB in cerebrum is established within 1-5 min after intravenous injection. We propose a new approach to the analysis of R-IQNB time-activity data that yields reliable quantitative estimates of k3, k4, and the nonspecific binding equilibrium constant (Keq) by either compartmental or graphical analysis. The approach is based on determining the free unbound fraction of radiolabeled ligand in blood and an estimate of K1.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Encéfalo/metabolismo , Quinuclidinil Benzilato/análogos & derivados , Receptores Colinérgicos/metabolismo , Algoritmos , Animais , Transporte Biológico , Barreira Hematoencefálica , Cerebelo/metabolismo , Radioisótopos do Iodo , Masculino , Modelos Biológicos , Quinuclidinil Benzilato/sangue , Quinuclidinil Benzilato/metabolismo , Quinuclidinil Benzilato/farmacocinética , Ratos , Ratos Endogâmicos
16.
J Cereb Blood Flow Metab ; 8(3): 346-56, 1988 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3366796

RESUMO

Local cerebral glucose utilization assayed by the [14C]deoxyglucose ([14C]DG) method and calculated by means of its operational equation with values for the rate constants and lumped constant determined in rats under physiological conditions remains relatively stable with variations in arterial plasma glucose concentration within the normoglycemic range. Large changes in arterial plasma glucose level may, however, significantly alter the values of these constants and lead to artifactual results. Values for the lumped constant have been measured and reported for a wide range of arterial plasma glucose concentrations ranging from hypoglycemia to hyperglycemia in the rat (Schuier et al., 1981; Suda et al., 1981; Pettigrew et al., 1983). In the present study we have redetermined the rate constants in rats with arterial plasma glucose levels clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM) by a glucose clamp technique. The rate constants for the transport of DG from plasma to brain, K1*, and its phosphorylation in tissue, k3*, were found to decline with increasing plasma glucose levels, while the rate constant for its transport back from brain to plasma, k*2, remained relatively unchanged from its value in normoglycemia. These rate constants were used together with the previously determined values for the lumped constants to calculate local rates of cerebral glucose utilization in three groups of rats in which arterial plasma glucose levels were clamped at approximately 350, 450, and 550 mg/dl (i.e., 19, 25, and 31 mM). Average glucose utilization in the brain as a whole was unchanged in hyperglycemia from the values calculated in normoglycemic rats with the standard normal set of constants. Changes in the rate of glucose utilization were found, however, in the hypothalamus, globus pallidus, and amygdala during hyperglycemia.


Assuntos
Encéfalo/metabolismo , Glucose/metabolismo , Hiperglicemia/metabolismo , Animais , Estado de Consciência , Masculino , Matemática , Ratos , Ratos Endogâmicos
17.
J Cereb Blood Flow Metab ; 13(3): 438-47, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8478402

RESUMO

Correlational analysis of regional cerebral glucose metabolism (rCMRglc) obtained by high-resolution positron emission tomography (PET) has demonstrated reduced neocortical rCMRglc interactions in mildly/moderately demented patients with probable Alzheimer's disease (AD). Thus, identification of individual differences in patterns of rCMRglc interactions may be important for the early detection of AD, particularly among individuals at greater risk for developing AD (e.g., those with a family history of AD). Recently, a statistical procedure, using multiple regression and discriminant analysis, was developed to assess individual differences in patterns of rCMRglc interdependencies. We applied this new statistical procedure to resting rCMRglc PET data from mildly/moderately demented patients with probable AD and age/sex-matched controls. The aims of the study were to identify a discriminant function that would (a) distinguish patients from controls and (b) identify an AD pattern in an individual at risk for AD with isolated memory impairment whose initial PET scan showed minor abnormalities, but whose second scan showed parietal hypometabolism, coincident with further cognitive decline. Two discriminant functions, reflecting interactions involving regions most involved in reduced correlations in probable AD, correctly classified 87% of the patients and controls, and successfully identified the first scan of the at-risk individual as AD (probability > 0.70). The results suggest that this statistical approach may be useful for the early detection of AD.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Desoxiglucose/análogos & derivados , Desoxiglucose/metabolismo , Análise Discriminante , Feminino , Fluordesoxiglucose F18 , Glucose/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Fatores de Risco , Fatores de Tempo , Distribuição Tecidual
18.
Am J Psychiatry ; 136(11): 1424-7, 1979 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-227281

RESUMO

The authors compared total night sleep measures and REM sleep architecture values for normal control subjects (N = 36), unipolar depressed patients (N = 36), and bipolar depressed patients (N = 22). The unipolar and bipolar patients had significantly greater fragmentation of REM periods than control subjects, and bipolar patients showed greater fragmentation of REM periods than unipolar patients. In both the unipolar and bipolar samples, the duration of successive REM periods was related to the total number of REM periods during sleep.


Assuntos
Transtorno Bipolar/psicologia , Depressão/psicologia , Sono REM , Ritmo Delta , Delusões/psicologia , Feminino , Humanos , Masculino , Vigília
19.
Neurology ; 41(10): 1549-53, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1922794

RESUMO

Monozygotic (MZ) twin pairs concordant for dementia of the Alzheimer type (DAT) or for proven Alzheimer's disease (AD) have a significantly higher frequency of a positive family history (DAT or AD in at least one first-degree relative, p less than 0.002) than do discordant MZ twin pairs, consistent with a lesser predicted distribution of proportions of surviving first-degree relatives without DAT (or AD) (p less than 0.001). The results suggest that concordant MZ twin pairs with DAT (or AD) have a heritable form of disease. AD in discordant twins may result from environmental influences or from a somatic chromosomal change following zygotic division.


Assuntos
Doença de Alzheimer/genética , Doenças em Gêmeos/genética , Gêmeos Monozigóticos , Adulto , Idoso , Humanos , Pessoa de Meia-Idade
20.
Neuropsychologia ; 37(6): 625-36, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10390024

RESUMO

Patients with left temporal lobe epilepsy demonstrate language impairments that are not well understood. To explore abnormal patterns of brain functional connections with respect to language processing, we applied a principal component analysis to resting regional cerebral metabolic data obtained with positron emission tomography in patients with right- and left-sided temporal lobe epilepsy and controls. Two principal components were expressed differentially among the groups. One principal component comprised a pattern of metabolic interactions involving left inferior frontal and left superior temporal regions-corresponding to Broca's and Wernicke's areas, respectively-and right mesial temporal cortex and right thalamus. Functional couplings between these brain regions were abnormally enhanced in the left-sided epilepsy patients. The right thalamic left superior temporal coupling was also abnormally enhanced in the right-sided epilepsy patients, but differentially from that in the left-sided patients. The other principal component was characterized by a pattern of metabolic interactions involving right and left mid prefrontal and right superior temporal cortex. Although both the right- and left-sided epilepsy patients showed decreased functional couplings between left mid prefrontal and the other brain regions, a weaker right-left mid prefrontal coupling in the left-sided epilepsy patients best distinguished them from the right-sided patients. The two mutually independent, abnormal metabolic patterns each predicted verbal intelligence deficits in the patients. The findings suggest a site-dependent reorganization of two independent, language-subserving pathways in temporal lobe epilepsy.


Assuntos
Encéfalo/metabolismo , Epilepsia do Lobo Temporal/metabolismo , Transtornos da Linguagem , Tomografia Computadorizada de Emissão , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Dominância Cerebral/fisiologia , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/fisiopatologia , Análise Fatorial , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/fisiopatologia , Glucose/metabolismo , Humanos , Transtornos da Linguagem/classificação , Transtornos da Linguagem/diagnóstico por imagem , Transtornos da Linguagem/fisiopatologia , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Vias Neurais/fisiopatologia , Lobo Temporal/metabolismo , Lobo Temporal/fisiopatologia , Tálamo/metabolismo , Tálamo/fisiopatologia , Comportamento Verbal/fisiologia
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