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1.
Phys Rev Lett ; 131(4): 046001, 2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37566829

RESUMO

Nuclear magnetic resonance measurements of the magnetic susceptibility of superfluid ^{3}He imbibed in anisotropic aerogel reveal anomalous behavior at low temperatures. Although the frequency shift clearly identifies a low-temperature phase as the B phase, the magnetic susceptibility does not display the expected decrease associated with the formation of the opposite-spin Cooper pairs. This susceptibility anomaly appears to be the predicted high-field behavior corresponding to the Ising-like magnetic character of surface Andreev bound states within the planar aerogel structures.

2.
Phys Rev Lett ; 124(2): 025302, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-32004035

RESUMO

It is known that both magnetic and nonmagnetic impurities suppress unconventional superconductivity. Here we compare their effect on the paradigm unconventional superconductor, superfluid ^{3}He, using highly dilute silica aerogel. Switching magnetic to nonmagnetic scattering in the same physical system is achieved by coating the aerogel surface with ^{4}He. We find a marginal influence on the transition temperature itself. However, we have discovered that the A phase, which breaks time reversal symmetry, is strongly influenced, while the isotropic B phase is unchanged. Importantly, this occurs only if the impurities are anisotropically distributed on a global scale.

3.
Br J Surg ; 104(8): 1028-1036, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28376246

RESUMO

BACKGROUND: Deficiencies in non-technical skills (NTS) have been increasingly implicated in avoidable operating theatre errors. Accordingly, this study sought to characterize the impact of surgeon and anaesthetist non-technical skills on time to crisis resolution in a simulated operating theatre. METHODS: Non-technical skills were assessed during 26 simulated crises (haemorrhage and airway emergency) performed by surgical teams. Teams consisted of surgeons, anaesthetists and nurses. Behaviour was assessed by four trained raters using the Non-Technical Skills for Surgeons (NOTSS) and Anaesthetists' Non-Technical Skills (ANTS) rating scales before and during the crisis phase of each scenario. The primary endpoint was time to crisis resolution; secondary endpoints included NTS scores before and during the crisis. A cross-classified linear mixed-effects model was used for the final analysis. RESULTS: Thirteen different surgical teams were assessed. Higher NTS ratings resulted in significantly faster crisis resolution. For anaesthetists, every 1-point increase in ANTS score was associated with a decrease of 53·50 (95 per cent c.i. 31·13 to 75·87) s in time to crisis resolution (P < 0·001). Similarly, for surgeons, every 1-point increase in NOTSS score was associated with a decrease of 64·81 (26·01 to 103·60) s in time to crisis resolution in the haemorrhage scenario (P = 0·001); however, this did not apply to the difficult airway scenario. Non-technical skills scores were lower during the crisis phase of the scenarios than those measured before the crisis for both surgeons and anaesthetists. CONCLUSION: A higher level of NTS of surgeons and anaesthetists led to quicker crisis resolution in a simulated operating theatre environment.


Assuntos
Anestesistas/normas , Competência Clínica/normas , Cirurgiões/normas , Obstrução das Vias Respiratórias/prevenção & controle , Anestesistas/educação , Conscientização , Perda Sanguínea Cirúrgica/prevenção & controle , Tomada de Decisão Clínica , Comunicação , Humanos , Capacitação em Serviço/métodos , Relações Interprofissionais , Liderança , Treinamento por Simulação/métodos , Cirurgiões/educação
4.
Nat Commun ; 15(1): 201, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172106

RESUMO

Superfluid 3He is a paradigm for odd-parity Cooper pairing, ranging from neutron stars to uranium-based superconducting compounds. Recently it has been shown that 3He, imbibed in anisotropic silica aerogel with either positive or negative strain, preferentially selects either the chiral A-phase or the time-reversal-symmetric B-phase. This control over basic order parameter symmetry provides a useful model for understanding imperfect unconventional superconductors. For both phases, the orbital quantization axis is fixed by the direction of strain. Unexpectedly, at a specific temperature Tx, the orbital axis flops by 90∘, but in reverse order for A and B-phases. Aided by diffusion limited cluster aggregation simulations of anisotropic aerogel and small angle X-ray measurements, we are able to classify these aerogels as either "planar" and "nematic" concluding that the orbital-flop is caused by competition between short and long range structures in these aerogels.

5.
Sci Total Environ ; 880: 163266, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37028654

RESUMO

In urban areas, exposure to greenspace has been found to be beneficial to human health. The biodiversity hypothesis proposed that exposure to diverse ambient microbes in greener areas may be one pathway leading to health benefits such as improved immune system functioning, reduced systemic inflammation, and ultimately reduced morbidity and mortality. Previous studies observed differences in ambient outdoor bacterial diversity between areas of high and low vegetated land cover but didn't focus on residential environments which are important to human health. This research examined the relationship between vegetated land and tree cover near residence and outdoor ambient air bacterial diversity and composition. We used a filter and pump system to collect ambient bacteria samples outside residences in the Raleigh-Durham-Chapel Hill metropolitan area and identified bacteria by 16S rRNA amplicon sequencing. Geospatial quantification of total vegetated land or tree cover was conducted within 500 m of each residence. Shannon's diversity index and weighted UniFrac distances were calculated to measure α (within-sample) and ß (between-sample) diversity, respectively. Linear regression for α-diversity and permutational analysis of variance (PERMANOVA) for ß-diversity were used to model relationships between vegetated land and tree cover and bacterial diversity. Data analysis included 73 ambient air samples collected near 69 residences. Analysis of ß-diversity demonstrated differences in ambient air microbiome composition between areas of high and low vegetated land (p = 0.03) and tree cover (p = 0.07). These relationships remained consistent among quintiles of vegetated land (p = 0.03) and tree cover (p = 0.008) and continuous measures of vegetated land (p = 0.03) and tree cover (p = 0.03). Increased vegetated land and tree cover were also associated with increased ambient microbiome α-diversity (p = 0.06 and p = 0.03, respectively). To our knowledge, this is the first study to demonstrate associations between vegetated land and tree cover and the ambient air microbiome's diversity and composition in the residential ecosystem.


Assuntos
Biodiversidade , Ecossistema , Humanos , RNA Ribossômico 16S/genética , Modelos Lineares , Bactérias , Árvores/genética
6.
Science ; 158(3808): 1592-4, 1967 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-6060366

RESUMO

Electrical stimulation of the rat's olfactory bulb or lateral olfactory tract elicited unit discharges in the region of the medial forebrain bundle of the lateral hypothalamus, with latencies of 4 to 25 milliseconds. Unit responses in this area were driven by odors in preparations that were paralyzed to prevent breathing artifacts.


Assuntos
Hipotálamo/anatomia & histologia , Sistema Límbico/fisiologia , Animais , Estimulação Elétrica , Odorantes , Ratos
7.
Br J Pharmacol ; 151(8): 1204-15, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17603555

RESUMO

BACKGROUND AND PURPOSE: AMP-activated protein kinase (AMPK) is activated by metformin, phenformin, and the AMP mimetic, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). We have completed an extensive study of the pharmacological effects of these drugs on AMPK activation, adenine nucleotide concentration, transepithelial amiloride-sensitive (I(amiloride)) and ouabain-sensitive basolateral (I(ouabain)) short circuit current in H441 lung epithelial cells. EXPERIMENTAL APPROACH: H441 cells were grown on permeable filters at air interface. I(amiloride), I(ouabain) and transepithelial resistance were measured in Ussing chambers. AMPK activity was measured as the amount of radiolabelled phosphate transferred to the SAMS peptide. Adenine nucleotide concentration was analysed by reverse phase HPLC and NAD(P)H autofluorescence was measured using confocal microscopy. KEY RESULTS: Phenformin, AICAR and metformin increased AMPK (alpha1) activity and decreased I(amiloride). The AMPK inhibitor Compound C prevented the action of metformin and AICAR but not phenformin. Phenformin and AICAR decreased I(ouabain) across H441 monolayers and decreased monolayer resistance. The decrease in I(amiloride) was closely related to I(ouabain) with phenformin, but not in AICAR treated monolayers. Metformin and phenformin increased the cellular AMP:ATP ratio but only phenformin and AICAR decreased cellular ATP. CONCLUSIONS AND IMPLICATIONS: Activation of alpha1-AMPK is associated with inhibition of apical amiloride-sensitive Na(+) channels (ENaC), which has important implications for the clinical use of metformin. Additional pharmacological effects evoked by AICAR and phenformin on I(ouabain), with potential secondary effects on apical Na+ conductance, ENaC activity and monolayer resistance, have important consequences for their use as pharmacological activators of AMPK in cell systems where Na+K+ATPase is an important component.


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Complexos Multienzimáticos/efeitos dos fármacos , Fenformin/farmacologia , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Ribonucleotídeos/farmacologia , Sódio/metabolismo , Proteínas Quinases Ativadas por AMP , Nucleotídeos de Adenina/metabolismo , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Amilorida , Aminoimidazol Carboxamida/farmacologia , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Células Epiteliais , Canais Epiteliais de Sódio/efeitos dos fármacos , Fluorescência , Humanos , Pulmão , Microscopia Confocal , Complexos Multienzimáticos/metabolismo , Ouabaína , Proteínas Serina-Treonina Quinases/metabolismo
8.
Mol Plant Microbe Interact ; 6(5): 616-27, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8274773

RESUMO

The molecular and genetic control of the interaction between tomato races of Xanthomonas campestris pv. vesicatoria (XcvT) and tomato was studied. Based on inoculation phenotype and analysis of in planta bacterial growth, tomato line Hawaii 7998 is resistant to XcvT race 1 75-3 but not to XcvT race 2 89-1. Two cosmid clones from a genomic library of XcvT race 1 75-3 converted the normally virulent race 2 89-1 to avirulence on Hawaii 7998. The two clones contained the previously isolated, nonhost avirulence gene avrRxv, and their activity was localized to a 2.1-kbp subclone of avrRxv. avrRxv inhibits growth of race 2 89-1 in the resistant line Hawaii 7998 and an insertional mutation in avrRxv prevents this inhibition. In addition, a dramatic increase in electrolyte leakage of leaves of Hawaii 7998 occurred after 12-hr postinfiltration with race 2 89-1 carrying avrRxv. The nucleotide sequence of avrRxv revealed one major open reading frame (ORF) that accords well with activity analysis of nested deletions. ORF 2-2 encodes a putative protein of 374 amino acids with a molecular weight of 42.1 kDa and a pI of 10.7. Inheritance of the avrRxv-specific resistance in Hawaii 7998 was studied in a total of 587 F2 individuals from crosses between Hawaii 7998 and susceptible lines. The inheritance of avrRxv-specific resistance in Hawaii 7998 appears to be governed by more than one locus.


Assuntos
Genes Bacterianos , Verduras/microbiologia , Xanthomonas/genética , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Sequência de Bases , Clonagem Molecular , DNA Bacteriano , Imunidade Inata , Dados de Sequência Molecular , Doenças das Plantas , Análise de Sequência de DNA , Deleção de Sequência , Virulência/genética , Xanthomonas/patogenicidade
9.
J Comp Neurol ; 271(4): 507-18, 1988 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-2838532

RESUMO

Cytochrome oxidase staining of the rat olfactory bulb external plexiform layer (EPL) produces a darkly stained intermediate zone bordered by lightly stained superficial and deep zones. Similar zonal staining was seen in cats, rabbits, and hamsters. These zones vary in relative thickness around the circumference of the olfactory bulb; the deep zone is proportionally thicker in the most dorsal and ventral parts of the bulb. Tufted cell somata are unevenly distributed within the EPL; the outer part of the EPL has more somata. The distribution of the cytochrome oxidase reaction product shows that the darkly stained intermediate zone is not produced by staining of tufted cell somata. Zones of cytochrome oxidase staining correspond to the sublaminar distribution of mitral and tufted cell basal dendrites. This was demonstrated by labeling mitral and tufted cells with small extracellular horseradish peroxidase injections and processing alternate sections for horseradish peroxidase and for cytochrome oxidase. Because there was cross-reaction of the cytochrome oxidase procedure with horseradish peroxidase, it was possible to trace many neurons through both series of sections. Middle tufted cells of the superficial EPL have basal dendrites confined to the superficial zone of light cytochrome oxidase staining. Internal tufted cells and middle tufted cells of the intermediate zone send their basal dendrites into the intermediate zone. One group of mitral cells (type I) has basal dendrites confined to the deep zone of lighter cytochrome oxidase staining. A second group of mitral cells (type II) and tufted cells of the intermediate EPL has basal dendrites primarily confined to the intermediate zone of dark cytochrome oxidase staining. The correlation of the enzyme staining with the dendritic laminar patterns supports the existence of three relatively distinct sublaminae in the EPL and supports the designation of two types of mitral cells. The staining pattern also provides an independent method for evaluating the sublaminae of the EPL without the necessity of labeling individual groups of cells. Finally, the staining pattern suggests that the intermediate zone of the EPL may be subjected to more tonic synaptic input, causing it to have an increased level of metabolic activity.


Assuntos
Dendritos/enzimologia , Complexo IV da Cadeia de Transporte de Elétrons/análise , Bulbo Olfatório/enzimologia , Animais , Dendritos/ultraestrutura , Estimulação Elétrica , Histocitoquímica , Masculino , Bulbo Olfatório/ultraestrutura , Ratos , Ratos Endogâmicos
10.
J Comp Neurol ; 304(4): 544-54, 1991 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-2013649

RESUMO

Sensory systems rely upon spatially organized projections for the faithful transfer of receptor activity into the central nervous system. While the mammalian olfactory nerve shows a regional topographical organization, data on the sources of variation within this projection are scarce. We evaluated the degree of precision of olfactory bulb glomerular innervation from the olfactory nerve layer (ONL) by making small cuts across the trajectory of the olfactory nerve fibers and assessing the resulting denervation by wheat germ agglutinin-horseradish peroxidase (WGA-HRP) labeling of primary nerve fibers. In control animals (no ONL cut), the ONL and glomerular layer showed intense labeling around the entire circumference of the bulb. Transneuronal labeling of the mitral cell layer and the external plexiform layer was also observed in animals surviving at least 2 days, which allowed us to study the nerve fiber innervation of second order cells as well. ONL cuts on the lateral face of the bulb produced a stripe of denervation, as evidenced by the absence of primary and transneuronal label in a well-defined region. Fascicles of fibers within the ONL were never observed to enter the denervated region from more than one or two glomerular widths away, indicating a relatively tight limit of variation in the spatial termination of olfactory nerve fibers on the lateral bulb surface. This limit of variation does not hold around the circumference of the bulb since similar ONL cuts on the dorsal surface failed to produce a distinct stripe of denervation. Field potential measurements from the ONL after similar cuts supported the anatomic findings. These results show that primary olfactory axons and their terminals lie in parallel along the lateral face of the olfactory bulb. These spatial relationships of olfactory input to the bulb are maintained in the second order connections. This organization allows one to study the spatial aspects of interneuronally mediated synaptic mechanisms involved in olfactory coding.


Assuntos
Bulbo Olfatório/citologia , Animais , Denervação , Eletrofisiologia , Peroxidase do Rábano Silvestre , Masculino , Bulbo Olfatório/fisiologia , Ratos , Aglutininas do Germe de Trigo
11.
J Comp Neurol ; 226(3): 346-56, 1984 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-6747027

RESUMO

The output cells of the main olfactory bulb, the mitral and tufted cells, can be categorized into subclasses on the basis of their intrabulbar dendritic and axonal characteristics. Their form was studied in rats following labeling by iontophoretic injection of horseradish peroxidase into the external plexiform layer (EPL). The fact that these extracellular injections labeled small numbers of neurons permitted reconstruction of individual cells. The injection depth within the EPL determined the type of cells labeled. Secondary dendrites of each cell type lay in one of three partially overlapping zones in the EPL. The deepest zone contained the secondary dendrites of one group of mitral cells (Type I), which had the deepest and longest dendrites of the output cells. An intermediate zone of the EPL contained the secondary dendrites of middle tufted and a second class of mitral cells (Type II). The superficial zone, adjacent to the glomerular layer, contained the relatively short, asymmetric dendritic fields of external tufted cells. The few labeled internal tufted cells had secondary dendrites in either the intermediate or deep zones. Every cell type, except the Type I mitral cells, had axon collaterals in the internal plexiform and upper granule cell layers. No cell types had axons re-entering the EPL. These results for output cells combined with our previous observations on granule cells point to a functional sublaminar organization of the EPL that has not previously been proposed.


Assuntos
Bulbo Olfatório/citologia , Animais , Axônios/ultraestrutura , Contagem de Células , Dendritos/ultraestrutura , Bulbo Olfatório/anatomia & histologia , Ratos , Ratos Endogâmicos
12.
J Comp Neurol ; 307(1): 57-64, 1991 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-1856320

RESUMO

It has been suggested that the principal output cells of the main olfactory bulb, the mitral cells, along with the glomerulus they enter, form an anatomical and functional column. To test the extent to which mitral cell somata lying close together in the mitral cell layer are connected to the same glomerulus, we reconstructed 267 mitral cells labeled by extracellular injections of horseradish peroxidase (HRP) in the external plexiform layer. Results show that apical dendrites tilt rostrally from the somata to the glomeruli and this tilt is gradually greater as the somata are located more and more rostrally in the olfactory bulb. The apical dendrites of most mitral cells in the same region of the bulb are parallel. We analyzed the degree to which dendrites were parallel by measuring the difference in angle of all pairs of apical dendrites in each section, with the restriction that no cells were separated by more than 500 microns. About half of these pairs of dendrites differed in angle by 20 degrees or less and were therefore said to be parallel. The degree of parallelism did not vary with the cell pair location or with intercell distance. Study of glomerular connections of pairs of mitral cells as a function of intercell distance revealed that 96% of mitral cells connected to the same glomerulus were separated by less than 120 microns, while 72% of cells connected to adjacent glomeruli and only 29% of cells connected to distant, i.e., nonadjacent, glomeruli were separated by less than 120 microns.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Dendritos/ultraestrutura , Bulbo Olfatório/citologia , Animais , Peroxidase do Rábano Silvestre , Vias Neurais/citologia , Bulbo Olfatório/crescimento & desenvolvimento , Ratos , Ratos Endogâmicos
13.
J Comp Neurol ; 217(2): 227-37, 1983 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-6886054

RESUMO

Studies on the morphological organization of the main olfactory bulb have indicated that there are subpopulations of granule cells with different dendritic patterns in the external plexiform layer (EPL). Small, extracellular injections of horseradish peroxidase (HRP) were made iontophoretically into superficial and deep parts of the EPL and the granule cell layer (GCL) in adult rats. Superficial EPL injections principally labeled superficial granule cell somata, whereas deep EPL injections labeled both superficial and deep granule cell somata. Injections in the superficial GCL labeled granule cell dendritic processes extending across the entire EPL. However, deep GCL injections labeled few granule cell dendrites in the superficial EPL, but labeled many such processes in the deep EPL. These results were the same in material processed with the Hanker-Yates procedure, where the morphology of individual neurons could be studied, and in the more sensitive tetramethyl benzidine procedure. Serial reconstructions of individual granule cells were made from both HRP and Golgi-Kopsch material. The distal dendrites of deep granule cells reached only as far as the deep EPL, where they branched extensively and had many dendritic spines. The dendrites of superficial granule cells, however, reached the most superficial part of the EPL where they ramified most extensively. The superficial granule cells typically had a higher spine density in the superficial part of the EPL than in the deep part. On the basis of these results, we conclude that the superficial granule cells predominantly innervate the superficial EPL and that the deep granule cells exclusively influences on the bulbar output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses. Since the secondary dendrites of the tufted cells ramify in the superficial EPL and the dentrites of most mitral cells ramify in deep EPL, the superficial and deep granule cells may preferentially modulate the responses of tufted and mitral cells, respectively.


Assuntos
Bulbo Olfatório/citologia , Animais , Dendritos/ultraestrutura , Interneurônios/ultraestrutura , Condutos Olfatórios/anatomia & histologia , Ratos , Ratos Endogâmicos
14.
J Comp Neurol ; 194(3): 519-34, 1980 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-7451680

RESUMO

The organization of the projection of olfactory bulb output cells was studied in the rat by injection of horseradish peroxidase (HRP) into the piriform cortex or olfactory tubercle. We made single HRP injections into small cuts in the fiber layer of the projection areas in order to enhance uptake by axons and to confine the region of HRP uptake. Following most of these injections, HRP-labeled axons could be traced in discrete fascicles through the fiber layer of the cortex or tubercle. These observations indicate that axons innervating the piriform cortex do not emit many long collaterals after they leave the lateral olfactory tract. HRP-labeled cells were generally observed throughout the ipsilateral olfactory bulb, but there were regions of greater density of labeled cells that differed in the various brains. The differences among the distributions of labeled mitral and tufted cells were analyzed statistically in 39 brains to test whether they varied systematically with injection site. In these analyses, the olfactory bulb was divided into 30 standard regions, and the labeled cells in each regions were counted. The distributions of labeled cells were similar for brains where injections were made into similar regions of the piriform cortex. The variations in density of labeled cells of the dorsal and anterior regions of the olfactory bulb were most strongly correlated with the positions of cortical injections. In contrast, the posterior medial regions of the bulb were heavily labeled after almost all injections. The ventral portions of the olfactory bulb were most heavily labeled after injections into the olfactory tubercle.


Assuntos
Sistema Nervoso Central/citologia , Bulbo Olfatório/citologia , Condutos Olfatórios/citologia , Animais , Axônios/ultraestrutura , Peroxidase do Rábano Silvestre , Ratos
15.
J Comp Neurol ; 260(3): 378-91, 1987 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-3298331

RESUMO

Several types of short axon cells of the mammalian olfactory bulb have been described after Golgi impregnation. Two of these types have been observed in our material after treatment with the NADPH-diaphorase procedure or after immunohistochemistry for neuropeptide-Y (NPY). The cells stained by the two procedures have similar morphologies and distributions. A less extensive series of observations confirms that similar cells also display somatostatin (SS)-like immunoreactivity. One of these cell types corresponds to the superficial short axon cell of Golgi and electron microscopic studies. The dendrites of this cell lie within the periglomerular region and in the superficial external plexiform layer (EPL), generally lying parallel to the glomerular layer. In some cases the axon has been traced across the EPL into the granule cell layer (GCL). This cell may provide another route of interaction between the periglomerular region and the granule cells in addition to the influences conducted by basal dendrites and axon collaterals of some mitral and tufted cells. A type of deep short axon cell is also visible with these two procedures. It lies deep in the granule cell layer, frequently near the ventricular layer and its dendrites lie parallel to that layer. This deep short axon cell is stained with much greater frequency by the NADPH-diaphorase and NPY procedures than is the superficial short axon cell. It corresponds most closely to the Blanes or Golgi cells of the Golgi impregnation literature, but it appears to differ from these cells in the position and orientation of its dendrites. No spines have been observed on either the superficial or deep cells in this series. Many glomeruli are also stained by the NADPH-diaphorase procedure, but are not NPY or SS immunoreactive. This may provide additional evidence for functional differences between glomeruli in local regions of the olfactory bulb.


Assuntos
NADH NADPH Oxirredutases/metabolismo , NADPH Desidrogenase/metabolismo , Neuropeptídeo Y/metabolismo , Bulbo Olfatório/metabolismo , Peptídeos/metabolismo , Animais , Contagem de Células , Imunofluorescência , Histocitoquímica , Técnicas Imunoenzimáticas , Bulbo Olfatório/citologia , Ratos , Ratos Endogâmicos
16.
J Comp Neurol ; 339(1): 76-90, 1994 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-8106663

RESUMO

Two neuron types contact the Mauthner cell (M cell) in the axon cap, a specialized region of high electrical resistance surrounding the initial segment of the M cell axon. One type produces a mixed electrical and chemical inhibition of the M cell. The second sends axons into the central core of the axon cap, where they spiral around the initial segment making both conventional synapses and gap junction contacts. The origin and synaptic effects of these spiral fibers have not been studied previously. When goldfish M cells were filled with Lucifer yellow, presynaptic spiral fibers were seen in the axon cap. These fibers could be traced back through the medial longitudinal fasciculus to their somata, near the contralateral fifth nerve motor nucleus. The same somata were labeled by horseradish peroxidase injected extracellularly into the axon cap. Recordings were made in the axon cap and the M cell after stimulation of hindbrain areas near the spiral fiber somata and axons. Extracellularly, a negative potential was observed close to the termination of the spiral fibers and termed the spiral fiber potential (SFP). Intracellularly, a graded, short latency depolarization of the M cell corresponded to the SFP and could cause the M cell to spike. This depolarization did not shunt the membrane, indicating that it may be produced through gap junctions. Intracellular responses to hindbrain stimulation also had a chloride-dependent, second component that shunted the membrane during paired-pulse testing. This inhibitory second component was probably evoked by cells other than the spiral fiber cells themselves.


Assuntos
Carpa Dourada/fisiologia , Fibras Nervosas/fisiologia , Neurônios/fisiologia , Animais , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Estimulação Elétrica , Potenciais Evocados/fisiologia , Espaço Extracelular/fisiologia , Histocitoquímica , Peroxidase do Rábano Silvestre , Isoquinolinas , Fibras Nervosas/ultraestrutura , Vias Neurais/citologia , Vias Neurais/fisiologia , Neurônios/ultraestrutura , Sinapses/fisiologia
17.
J Comp Neurol ; 242(3): 415-24, 1985 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-4086669

RESUMO

The pattern of output of mitral and tufted cells of the rat olfactory bulb (OB) to layer Ia overlying the pars externa (pE) of the anterior olfactory nucleus (AON) has been studied in the rat by iontophoresis of horseradish peroxidase and Phaseolus vulgaris-leucoagglutinin. These agents labeled mitral and tufted cells and at least the proximal portion of their axons. In most cases we observed small branches from axons of the lateral olfactory tract that appear to terminate in the region of the pE AON, while the main axon could often be traced for considerable distances past these branches. These branches are assumed to terminate in the pE AON because they could not be traced to other terminal regions, because they ramify in layer Ia, and because they usually show small swellings characteristic of axons in terminal regions. Although each ramification could be extensive, we found that the positions of these small branches were related to the positions of the injections within the OB. Dorsal medial injections labeled dorsal branches. Ventral medial injections labeled ventral branches. Injections on the lateral face of the OB labeled intermediate branches. The centers of the regions within which branches were labeled were strongly correlated with the positions of the injection around the circumference. Comparison of the anterior-posterior axis of the OB produced no such strong correlation. Reconstructions of axons showed that terminal branches arise from both mitral and tufted cells, although at least some mitral cells are shown not to have such branches in the pE AON. Studies of the patterns of dendrites and terminals in the pE AON indicate that this region has the same pattern of layer Ia and Ib terminals seen in other olfactory cortical regions. The pE AON cell layer is intercalated just below the boundary between layers Ia and Ib. Since dendrites of the underlying pars lateralis of the AON (pL AON) penetrate into layer Ia over much of the pE AON, it is necessary to remember that at least part of the pL AON may also receive topographically organized inputs.


Assuntos
Mapeamento Encefálico , Neurônios/fisiologia , Bulbo Olfatório/anatomia & histologia , Nervo Olfatório/anatomia & histologia , Animais , Peroxidase do Rábano Silvestre , Iontoforese , Masculino , Microinjeções , Terminações Nervosas/anatomia & histologia , Neurônios/classificação , Condutos Olfatórios/anatomia & histologia , Fito-Hemaglutininas , Ratos
18.
Arch Neurol ; 32(9): 618-23, 1975 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-126052

RESUMO

Progressive electroencephalographic disorganization and decreased voltage amplitude in the late components of the averaged visual evoked potentials were recorded in the last two years of life of a patient with Down disease and Alzheimer degeneration. Taken together with quantitative histopathologic findings, the electrophysiologic alterations are interpreted in terms of recent evidence from an experimental animal model of dementia. Neurons with neurofibrillary degeneration become electrically inactive and contribute to the loss of voltage generators associated with neuron death in Alzheimer disease. Loss of voltage generators may result in disfacillitation and disinhibition of surviving neurons, thus causing the loss of normal rhythms.


Assuntos
Doença de Alzheimer/complicações , Demência/complicações , Síndrome de Down/complicações , Adulto , Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Tronco Encefálico/patologia , Córtex Cerebral/patologia , Síndrome de Down/patologia , Síndrome de Down/fisiopatologia , Eletroencefalografia , Potenciais Evocados , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Testes Psicológicos , Tálamo/patologia
19.
J Nucl Med ; 27(4): 560-2, 1986 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3712069

RESUMO

When [99mTc]DTPA is administered, a small fraction of the activity (presumably an impurity) is bound to plasma proteins. This causes an error in the calculation of glomerular filtration rate from plasma clearance. This paper presents two methods of laboratory quality control for measuring the fraction that binds to plasma proteins. One method involves in vitro binding to human serum albumin followed by gel filtration. The other method involves descending paper chromatography on wet pre-equilibrated anion exchange paper. In a series of 80 patients, correlation was demonstrated between laboratory characteristics and actual clinical performance of the [99mTc]DTPA preparation. Both laboratory methods appear suitable for routine quality control.


Assuntos
Ácido Pentético , Tecnécio , Proteínas Sanguíneas/metabolismo , Taxa de Filtração Glomerular , Humanos , Ligação Proteica , Controle de Qualidade
20.
J Nucl Med ; 32(9): 1821-5, 1991 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1880586

RESUMO

Development and validation of simplified renal clearance methods has required a research data base of multiple blood samples drawn over a substantial time interval, which is difficult to obtain for children. While the medical risks entailed in drawing multiple samples may be negligible, the problems of parental and institutional consent make such studies more difficult in the pediatric population. Scaling for patient size permits combining data from patients of different age and limits the number of studies required. A scaling technique is presented and evaluated here. With scaling, adult data can be used successfully to predict pediatric responses and to develop pediatric methods based on adult data alone. Inclusion of pediatric data improves the fit and permits development of generic methods that work with both adults and children.


Assuntos
Pediatria , Renografia por Radioisótopo/métodos , Adolescente , Criança , Pré-Escolar , Humanos , Ácido Iodoipúrico
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