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1.
Scand J Med Sci Sports ; 32 Suppl 1: 105-114, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34825736

RESUMO

The purpose of the present study was to investigate the physical performance of elite female football players during match play along with transient alterations in running performance following 1- and 5-min univariate peak periods. 54 elite female players from four top-level Norwegian teams were monitored for one season (n = 393 match observations), and physical performance data collected using STATSport GPS APEX. Results revealed significant differences in physical performance between the positions during full match play, particularly between wide and central players. Both full backs (FBs) and wide midfielders (WMs) covered more total distance (TD), high-speed running distance (HSRD), and sprint distance (SpD) than center backs (CBs) (p < 0.05-0.001), while WMs also covered more HSRD than both central midfielders (CMs) (p < 0.01) and forwards (FWs) (p < 0.05), and more acceleration -and deceleration distance (Accdist and Decdist ) than both CBs and CMs (p < 0.01-0.001). A similar pattern was observed for the peak period analysis, with FBs and WMs covering more SpD in peak 1 min than CBs and CM (p < 0.001) and more SpD in peak 5-min than CBs, CMs, and FWs (p < 0.001). Irrespective of the variable analyzed, greater distances were covered during the peak 5-min period than in the next-5 and mean 5-min periods (p < 0.001). Significant (p < 0.001), but small to trivial (Cohen's Dz : 0.07-0.20), decreases in distance covered were also observed for each variable following each univariate peak 5-min period. In conclusion, practitioners should account for differences in physical performance when developing training programs for female football players and be aware of transient reductions in physical performance following univariate peak 1- and 5-min periods. Specifically, the very high intensity in 1-min peak periods adds support to the principal of executing speed endurance activities during training to mirror and be prepared for the physical demands of match play.


Assuntos
Desempenho Atlético , Corrida , Feminino , Humanos , Sistemas de Informação Geográfica , Frequência Cardíaca , Desempenho Físico Funcional
3.
Nanotechnology ; 28(42): 425602, 2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-28930094

RESUMO

We report on plasma-assisted molecular beam epitaxial growth of almost randomly oriented, uniformly tilted, and vertically aligned self-assembled GaN nanowires (NWs), respectively, on different types of polycrystalline Ti foils. The NW orientation with respect to the substrate normal, which is affected by an in situ treatment of the foil surface before NW growth, depends on the crystallinity of the native oxide. Direct growth on the as-received foils results in the formation of ensembles of nearly randomly oriented NWs due to the strong roughening of the surface induced by chemical reactions between the impinging elements and Ti. Surface nitridation preceding the NW growth is found to reduce this roughening by transformation of the uppermost layers into TiN and TiO x N y species. These compounds are more stable against chemical reactions and facilitate the growth of uniformly oriented GaN NW ensembles on the surface of the individual grains of the polycrystalline Ti foils. If an amorphous oxide layer is present at the foil surface, vertically oriented NWs are obtained all across the substrate because this layer blocks the transfering of the epitaxial information from the underlying grains. The control of NW orientation and the understanding behind the achievement of vertically oriented NWs obtained in this study represent an important step towards the realization of GaN NW-based bendable devices on polycrystalline metal foils.

4.
Int J Sports Med ; 37(12): 966-972, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27551936

RESUMO

The present study evaluated the effect of a smaller, lighter ball on kicking speed and technical-tactical and physical match performance in high-level adult female footballers. In the laboratory test setting, the peak ball velocity was 6% higher with the new ball (NB) than the standard ball (SB) (26.5±0.5 vs. 25.1±0.5 m·s-1, p<0.05). However, during match-play, no differences were observed in mean heart rate (87±5 vs. 87±5%HRmax; p>0.05), blood lactate (90 min: 4.7±1.7 and 4.0±1.7 mmol·l-1; p>0.05), total distance covered (10.6±0.9 and 10.4±0.8 km; p>0.05), intense running (>16 km/h) (2.08±0.42 and 1.94±0.38 km; p>0.05) and match-induced decrement in Yo-Yo IR1 performance (28 vs. 31%, respectively, p<0.05) using NB compared to SB. Likewise, no difference was observed in the number of short, medium-range or long passes during matches played with the 2 ball types, and there was no difference in passing success rate (NB: 68±1% and SB: 68±1%, p>0.05). In conclusion, high-level adult female footballers had a higher kicking speed when using a smaller, lighter ball, but no differences were observed during match-play with the 2 ball types in respect of technical-tactical and physical match performance. The physical loading was high for the players when playing with both ball types.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Futebol/fisiologia , Equipamentos Esportivos , Adulto , Feminino , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Corrida/fisiologia , Adulto Jovem
5.
J Sports Med Phys Fitness ; 55(1-2): 25-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25642681

RESUMO

AIM: The aim of the present study was to assess the effect of short-burst high intensity training on speed and agility performance in 10-year-old male soccer players. METHODS: Pretest posttest experimental design. A training group (TG) (N.=20; age 10.5 SD ± 0.2), followed an 8 week intervention program, and with an corresponding control group (CG) (N.=12; age 10.4 SD ± 0.2). MAIN OUTCOME MEASURES: 10 m sprint, 20 m sprint and 20 m agility performance, and correlation between linear sprint and agility performance. Brower Timing System (USA) were used to record split and completion time. One way analysis of variance (ANOVA), two tailed paired t-test and Pearson's correlation r were used in statistical analyses. All analyses were performed using SPSS version 19.0. RESULTS: Findings from the present study showed significant improvement in agility performance (7.8%) and 20 m sprint (1.8%) (P<0.05). No significant performance increase was obtained in the CG. Furthermore the correlation between 10 m sprint and agility was r=0.40 and between 20 m sprint and agility performance r=0.58 (P<0.05). CONCLUSION: These results demonstrate that short-burst high intensity training increase speed and agility performance in 10-year-old male soccer players. The results also indicate a common variance between straight line sprinting and agility performance.


Assuntos
Atletas , Desempenho Atlético , Exercício Físico , Estudos de Casos e Controles , Criança , Humanos , Masculino , Aptidão Física , Futebol
6.
Eur J Clin Pharmacol ; 65(8): 795-801, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19308365

RESUMO

PURPOSE: Codeine/paracetamol (C/P) and levomepromazine (L) are frequently co-administered for the treatment of acute back pain, but the efficacy/effectiveness of this combination drug therapy has not been evaluated. The demethylation of codeine to morphine is catalyzed by the polymorphic enzyme cytochrome P450 2D6 (CYP2D6), of which levomepromazine (methotrimeprazine) is a known inhibitor. The aim of this study was to investigate whether low-dose levomepromazine inhibits the formation of morphine from codeine in a patient population of homozygous extensive (EM) and heterozygous extensive (HEM) metabolizers of CYP2D6. METHODS: Our patient cohort consisted of 29 patients hospitalized for acute back pain who were randomized to a 24-h treatment with either C/P (60 mg codeine + 1000 mg paracetamol) four times daily or to L+C/P (levomepromazine 5 + 5 + 5 + 10 mg + C/P) four times daily. After zero-urine sampling (baseline), the treatment was started and urine collected for 24 h. Blood samples were later genotyped for the CYP2D6*3, *4, and *6 polymorphisms by the PCR (LightCycler system) and for the *5 polymorphism using long PCR, to identify EM and HEM and to eliminate CYP2D6 poor metabolizers. Urine samples were analyzed using the CEDIA immunoassay and gas chromatography-mass spectrometry after enzymatic hydrolysis of glucuronide conjugates. O-demethylation ratios of codeine were calculated as hydrolyzed (total) concentrations of morphine/morphine + codeine. RESULTS: Twenty-two of the patients fulfilled the inclusion criteria, of whom ten were EM (five C/P and five L+C/P) and twelve were HEM (six C/P and six L+C/P) for functional CYP2D6 alleles. In the EM group, the median O-demethylation ratio was significantly higher (P = 0.016, Mann-Whitney test) after the C/P treatment (0.092, range 0.041-0.096) than after the L+C/P treatment (0.031, range 0.009-0.042). However, there was no significant difference between these two treatments in either the HEM group [n = 12; 0.024 (range 0.011-0.042) vs. 0.026 (range 0.009-0.041), respectively; P = 1.00] or in the combined EM/HEM group [11 C/P + 11 L+C/P; 0.041 (range 0.011-0.096) vs. 0.030 (range 0.009-0.042), respectively; P = 0.122]. CONCLUSIONS: Our study revealed significant inhibition in the O-demethylation of codeine to morphine in homozygous EM of CYP2D6 treated with low-dose levomepromazine and codeine/paracetamol, compared to treatment with codeine/paracetamol only. No significant difference could be detected in HEM or in the mixed and heterogenous group of EM/HEM. In patients prescribed this drug combination, the amount of morphine generated by the O-demethylation of codeine may be insufficient for effective pain relief. The therapeutic effect of codeine in the treatment of acute back pain should be assessed with and without levomepromazine.


Assuntos
Acetaminofen/metabolismo , Analgésicos não Narcóticos/farmacologia , Analgésicos Opioides/metabolismo , Codeína/metabolismo , Metotrimeprazina/farmacologia , Oxirredutases O-Desmetilantes/antagonistas & inibidores , Acetaminofen/administração & dosagem , Administração Oral , Adulto , Idoso , Analgésicos não Narcóticos/administração & dosagem , Analgésicos não Narcóticos/metabolismo , Analgésicos Opioides/administração & dosagem , Codeína/administração & dosagem , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP2D6/metabolismo , Esquema de Medicação , Feminino , Genótipo , Humanos , Dor Lombar/tratamento farmacológico , Masculino , Metotrimeprazina/administração & dosagem , Metilação/efeitos dos fármacos , Pessoa de Meia-Idade , Oxirredutases O-Desmetilantes/metabolismo , Urinálise
7.
Clin Exp Metastasis ; 20(4): 301-9, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12856717

RESUMO

A number of studies have emphasized the role of PAI-1 as an important regulator of tumor cell invasion and metastasis. The hallmark of primary tumors of the central nervous system and glioblastomas in particular is the diffuse invasion into the normal brain tissue. Since PAI-1 is expressed in such tumors, we studied the effect of adenoviral-mediated transfer of the PAI-1 gene in regulating the in vitro invasiveness of D54Mg glioma cells into Matrigel, and into fetal rat brain aggregates. Treatment of D54Mg cells with 50 MOI (multiplicity of infection) of the replication defective vector AdCMVPAI-1 increased PAI-1 expression 23-fold compared to control vectors, and the invasion through Matrigel was reduced by 67%. The motility of the cells was reduced by 58% compared to controls (indicating that inhibition of motility was the principal effect of PAI-1 in these cells). The ability of D54Mg tumor spheroids to invade fetal rat brain aggregates was not reduced by the PAI-1 gene transfer. The results show that overexpression of PAI-1 can inhibit glioma cell motility and invasion through extracellular matrix (ECM) components, like laminin and collagen, but does not inhibit tumor cell invasion in a three-dimensional invasion assay, simulating normal brain tissue having a different ECM and interstitial composition. The different results obtained in the two invasion assays reflect the complex biological effects of the uPA/PAI-1 system, and questions a simplistic view of PAI- I as an inhibitor of brain tumor invasion.


Assuntos
Adenoviridae/genética , Neoplasias Encefálicas/genética , Técnicas de Transferência de Genes , Glioma/genética , Inibidor 1 de Ativador de Plasminogênio/genética , Inibidores de Serina Proteinase/genética , Animais , Northern Blotting , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Adesão Celular/efeitos dos fármacos , Movimento Celular , Colágeno/metabolismo , Combinação de Medicamentos , Ensaio de Imunoadsorção Enzimática , Feto/metabolismo , Feto/patologia , Vetores Genéticos/genética , Glioma/metabolismo , Glioma/patologia , Humanos , Técnicas Imunoenzimáticas , Laminina/metabolismo , Invasividade Neoplásica , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Proteoglicanas/metabolismo , Ratos , Ratos Nus , Inibidores de Serina Proteinase/metabolismo , Esferoides Celulares/patologia , Células Tumorais Cultivadas
8.
Scand J Med Sci Sports ; 11(4): 223-8, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11476427

RESUMO

The method of removing the confounding effect of body mass on peak oxygen uptake simply by dividing the measured values by body mass has been questioned. The aim of the study was to find an expression of body mass for compensating for differences in body mass so as to achieve the best correlation to running performance. In a cross-sectional study, design peak oxygen uptake (VO2peak) was measured in 107 boys in the age range 8-17 years and 88 girls in the age range 8-16 years. The present study indicates that VO2peak do not increase in proportion to body mass during running, rather that VO2peak is inversely related to body mass. When using allometric regression standards with the sexes separated in gender groups, there was a tendency that boys achieved scaling factors closer to unity than did the girls. The increase in subcutaneous fat in the girls throughout the pubertal years is the most likely reason why body mass increased proportionally more than VO2peak in girls. The present study indicates that VO2peak when expressed as milliliters per kilogram per minute (ml kg(-1) min(-1)) is a poor denominator for VO2peak as a function of running performance in children and adolescents.


Assuntos
Constituição Corporal/fisiologia , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Corrida/fisiologia , Adolescente/fisiologia , Fatores Etários , Envelhecimento/fisiologia , Criança , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Análise de Regressão , Sensibilidade e Especificidade , Fatores Sexuais , Análise e Desempenho de Tarefas
9.
J Pediatr Surg ; 36(7): 1040-4, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11431772

RESUMO

BACKGROUND: Matrix metalloproteinases (MMPs) and their endogenous inhibitors (tissue inhibitors of MMPs; TIMPs) have been shown to correlate with in vitro invasiveness and clinical outcome in several adult malignancies. The importance of MMP and TIMP expression in neuroblastoma (NB) and primitive neuroectodermal tumors (PNET) is incompletely understood. The aim of the current study was to relate in vitro invasion of NB and PNET cell lines with MMP and TIMP expression and evaluate the effect of a synthetic MMP inhibitor. Furthermore, S100A4 levels were determined because recent reports have suggested a possible association between MMPs, TIMPs, and the metastasis-associated gene S100A4. METHODS: Expression of MMPs, TIMPs, and S100A4 was evaluated at both mRNA and protein levels in 2 human NB and 2 PNET cell lines. In vitro invasion and effects of the synthetic MMP inhibitor Marimastat were assessed in the Transwell chamber assay. RESULTS: The most invasive cells expressed the highest levels of MMPs and S100A4. Marimastat reduced invasion by 30%. CONCLUSIONS: In vitro invasion correlated with MMP and S100A4 expression. The fact that Marimastat reduced in vitro invasion is encouraging for further studies on a possible therapeutic application for proteinase inhibitors.


Assuntos
Metaloproteinases da Matriz/análise , Invasividade Neoplásica/genética , Neuroblastoma/química , Neuroblastoma/genética , Tumores Neuroectodérmicos Primitivos/química , Tumores Neuroectodérmicos Primitivos/genética , Proteínas S100/genética , Northern Blotting , Ensaio de Imunoadsorção Enzimática , Humanos , Metaloproteinases da Matriz/genética , Neuroblastoma/patologia , Tumores Neuroectodérmicos Primitivos/patologia , RNA Mensageiro/análise , Proteína A4 de Ligação a Cálcio da Família S100 , Inibidores Teciduais de Metaloproteinases/análise , Células Tumorais Cultivadas/química , Células Tumorais Cultivadas/patologia
10.
Tidsskr Nor Laegeforen ; 120(29): 3567-70, 2000 Nov 30.
Artigo em Norueguês | MEDLINE | ID: mdl-11188387

RESUMO

BACKGROUND: Research and general experience regarding the importance of physical activity in adults on various parameters such as performance ability and weight control is often extrapolated to be valid for children and adolescents. MATERIAL AND METHODS: This article is a brief review of research on physical activity level and performance ability in children and adolescents. RESULTS: Findings regarding physical activity level and physical fitness are reviewed. INTERPRETATION: The absence of reference material which goes 20-30 years back in time as well as contradictive findings on whether changes in social structure have caused a reduction in physical activity, makes it difficult to draw conclusions. The relationship between physical activity and physical fitness is not clear. Growth per se leads to methodical problems regarding whether it is the activity or maturation that cause changes in physical parameters. Contradictory results might partly be a consequence of the different methods used. An important challenge in future research on physical fitness is to establish a reference material with valid measures of physical activity levels.


Assuntos
Exercício Físico , Aptidão Física , Adolescente , Criança , Feminino , Humanos , Masculino , Noruega , Pesquisa , População Rural , Fatores Sexuais , População Urbana
11.
J Telemed Telecare ; 5 Suppl 1: S34-6, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10534834

RESUMO

The North Norwegian Health Net is a comprehensive scheme to connect all health-care institutions in the area to a national computer network. Services available include telemedicine, e-mail and Web access. A general practitioner has responsibility for ensuring that the clinical information is correct. Medical departments are responsible for the content of their own Web pages. All institutions require authorization before connection to ensure data protection and security. Changes in communication between primary- and secondary-care sectors are being monitored. To date the implementation of the network programme has gone smoothly.


Assuntos
Redes de Comunicação de Computadores , Programas Nacionais de Saúde/organização & administração , Telemedicina/organização & administração , Medicina de Família e Comunidade , Humanos , Noruega , Serviços de Saúde Rural/organização & administração
12.
J Mol Cell Cardiol ; 24(5): 457-64, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1635071

RESUMO

The combined action of phosphatidylcholine preferring phospholipase C (PC-PLC) and intracellular lipases has recently been shown to cause glycerol output in energy deprived rat cardiomyocytes. In the present study we examined the effect of hypothermia and rewarming on PC-PLC evoked glycerol output in freshly isolated, calcium-tolerant myocytes. The cells were preincubated for 60 min at hypothermic (5 degrees C) or normothermic (37 degrees C) conditions in Krebs-Henseleit bicarbonate buffer (pH 7.4) supplemented with 1 mM DL-carnitine, 1% B.S.A. and 5 mM glucose. Addition of PC-PLC resulted in a significantly higher (P less than 0.05) output of glycerol in myocytes undergoing rewarming than in myocytes kept constantly at 5 degrees C or 37 degrees C. The values obtained for PC-PLC induced glycerol output (difference in glycerol output between incubations with and without PC-PLC) were 6.77 +/- 2.6 (37 degrees C), 4.54 +/- 1.7 (5 degrees C) and 22.85 +/- 5.9 (5-37 degrees C) nmol/10(6) cells.h. Rewarming in addition caused a significantly higher (P less than 0.05) leakage of lactate dehydrogenase (LDH) from the rewarmed cells as compared to cells at constant temperatures (5 degrees C or 37 degrees C). However, there was no additional effect of PC-PLC on LDH leakage. The elevated PC-PLC induced glycerol output in rewarmed myocytes was not related to a fall in the percentage of rod-shaped cells or a reduced cellular content of ATP, since no differences could be detected between the various myocyte preparations with respect to these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Glicerol/metabolismo , Hipotermia/metabolismo , Miocárdio/metabolismo , Fosfolipases Tipo C/fisiologia , Trifosfato de Adenosina/metabolismo , Animais , Membrana Celular/metabolismo , Homeostase/fisiologia , Temperatura Alta , Técnicas In Vitro , L-Lactato Desidrogenase/metabolismo , Masculino , Miocárdio/citologia , Ratos , Ratos Endogâmicos
13.
Microvasc Res ; 40(3): 341-57, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2084500

RESUMO

In this study cerebral capillary bed structure and the effects of chronic hypertension on these systems have been assessed in 6- to 7-month-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Capillary diameter (D), profile frequency (Na), volume fraction (Vv), and surface area (Sv) were quantitated by light microscopic morphometry of eight brain areas including the sensorimotor cortex and subfornical organ. Previously presented data from normotensive Sprague-Dawley rats (SpD) of similar age were also compared. Within each of the three rat strains, D, Na, Vv, and Sv varied among brain areas. For the sensorimotor cortex and subfornical organ, capillary profile frequency differed significantly among the three rat strains. In SHR and WKY, there was an inverse correlation between profile frequency and diameter, i.e., as Na increased among brain areas, D decreased. In six brain areas capillary volume fraction and surface area were identical in SHR and WKY, but were lower in SpD. Consistent differences between SHR and WKY were found only for the subfornical organ, which suggests some involvement of this structure in hypertension. Since there were few statistically significant differences between SHR and WKY and many statistically significant differences between the two normotensive strains, cerebral capillary bed structure seems to be independent of arterial blood pressure in most brain areas of these rats.


Assuntos
Encéfalo/irrigação sanguínea , Capilares/ultraestrutura , Circulação Cerebrovascular , Hipertensão/fisiopatologia , Animais , Capilares/fisiologia , Doença Crônica , Masculino , Microcirculação , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY
14.
Acta Ophthalmol (Copenh) ; 67(6): 724-6, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2618644

RESUMO

Lens capsule and aqueous humour from cataractous eyes with and without pseudo-exfoliation syndrome have been studied by SDS-PAGE electrophoresis. Four cataractous lenses with and four without pseudo-exfoliation were used. The pseudo-exfoliation positive capsule revealed two polypeptides not present in the control material, and accordingly, these components were regarded to be pseudo-exfoliation specific. The molecular weight of the respective polypeptides was estimated to be 14,400 and 16,300. No marked differences were found between the pseudo-exfoliation positive and negative aqueous humours.


Assuntos
Humor Aquoso/metabolismo , Cápsula do Cristalino/metabolismo , Doenças do Cristalino/metabolismo , Cristalino/metabolismo , Proteínas/metabolismo , Catarata/complicações , Catarata/metabolismo , Eletroforese em Gel de Poliacrilamida , Humanos , Doenças do Cristalino/complicações
16.
Ann N Y Acad Sci ; 529: 21-30, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3395069

RESUMO

The major hypothesis of this study is that there are differences among brain areas in capillary bed structure and function. Three general differences between circumventricular organ and non-CVO capillary beds were found. First, the PS products for AIB were about 300 times greater in CVO capillaries than in non-CVO (blood-brain barrier) capillaries. Second, the frequency of endothelial cell fenestrations was much greater in CVO capillaries than in non-CVO capillaries and the fenestrae may be structural modifications of endothelial cells that permit ready passage of solutes such as AIB. Third, the frequency of mitochondria was greater in BBB capillaries than in CVO capillaries; this high metabolic potential of BBB capillaries may be associated, in part, with "carrier-mediated" transport of various solutes between plasma and cerebral interstitial fluid. Capillary bed differences among all (i.e., both CVO and non-CVO) brain structures were also observed. Among these differences are: rate of blood flow, mean transit time of albumin, capillary volume and surface area, perfused microvessel blood volume, apparent percentage of perfused capillaries, PS products for AIB, and frequency within the endothelium of vesicular profiles.


Assuntos
Circulação Cerebrovascular , Ácidos Aminoisobutíricos/metabolismo , Animais , Volume Sanguíneo , Barreira Hematoencefálica , Capilares/anatomia & histologia , Capilares/metabolismo , Capilares/fisiologia , Modelos Cardiovasculares , Modelos Neurológicos , Albumina Sérica/metabolismo
17.
J Cereb Blood Flow Metab ; 7(2): 154-60, 1987 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3558498

RESUMO

A midbrain nucleus of the auditory system, the inferior colliculus, was used as a model for analyzing spatial correlations or "coupling" among capillary density, tissue glucose metabolism, and several measures of microvascular function in the rat. The capillary bed of the inferior colliculus was examined with stereological techniques, and physiological measures were obtained with radioactive tracers, quantitative autoradiography, and image processing. Within the colliculus, capillary density, volume fraction, length, and surface area were highest in the central nucleus where the packing densities of neuropil and perikarya are greatest. Rates of glucose metabolism and blood flow correlated closely with capillary density in a 3 X 2 matrix of collicular subregions in the sagittal and coronal planes. The strength of this correlation suggests that estimates of capillary density can be made from measurements of tissue glucose metabolism within this structure under normal conditions. Microvascular blood volume and transcapillary flux of a neutral amino acid, alpha-aminoisobutyric acid, were homogeneous throughout the colliculus. The studies demonstrate quantitatively in a single brain nucleus a close correspondence between cytoarchitecture, richness of the capillary bed, and complexity of neural activity (inferred from local measures of glucose metabolism and blood flow). Such relationships were suggested by Craigie 67 years ago.


Assuntos
Glucose/metabolismo , Colículos Inferiores/anatomia & histologia , Animais , Capilares/anatomia & histologia , Colículos Inferiores/irrigação sanguínea , Colículos Inferiores/fisiologia , Masculino , Microcirculação/fisiologia , Ratos , Ratos Endogâmicos
18.
Blood Vessels ; 23(6): 261-70, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3790742

RESUMO

Physiological and morphometric studies were conducted on the microvascular endothelium of four individual cerebral structures having different neural activities--the inferior colliculus, sensorimotor cortex (both gray matter regions), genu of the corpus callosum (white matter), and the subfornical organ (a circumventricular organ) of rats. The physiological data, obtained by quantitative autoradiography, produced new findings: the rate of blood-to-tissue flux across capillary endothelial cells of a neutral amino acid, 14C-alpha-aminoisobutyric acid, was 100-400 X more rapid in the subfornical organ than in gray and white matter regions, and the transit time of labeled albumin in the subfornical organ microcirculation was 7-12 X longer than in the blood-brain barrier regions. These quantitative studies suggest that circulating messengers, such as hormones, would have more prolonged receptor contact with capillary endothelial cells and greater rates of transendothelial passage in the subfornical organ than in gray or white matter. Capillary densities, volume fractions, and surface areas were similar for the inferior colliculus (which has the highest rates of tissue glucose metabolism and blood flow among blood-brain barrier regions) and the subfornical organ, but were significantly smaller for sensorimotor cortex and corpus callosum (about 35 and 70% lower, respectively). Electron microscopic morphometry of capillary endothelial cells in the inferior colliculus and corpus callosum indicated the ultrastructural basis of blood-brain barrier mechanisms in these regions--intercellular junctions that appeared tight, few cytoplasmic vesicular profiles, and no fenestrations. Analysis of endothelial cells in the subfornical organ demonstrated 7 X more vesicular profiles and 4 fenestrations per cross section of capillary. These findings represent structural evidence for high rates of solute flux across the capillary endothelium of circumventricular organs.


Assuntos
Encéfalo/irrigação sanguínea , Capilares/ultraestrutura , Animais , Capilares/fisiologia , Corpo Caloso/irrigação sanguínea , Endotélio , Colículos Inferiores/irrigação sanguínea , Masculino , Microscopia Eletrônica , Córtex Motor/irrigação sanguínea , Ratos , Ratos Endogâmicos , Órgão Subfornical/irrigação sanguínea
19.
Neuroendocrinology ; 44(4): 401-7, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3822073

RESUMO

The physiology and structure of capillary endothelial cells in the hypothalamic ventromedial and supraoptic nuclei and pituitary neural lobe were evaluated with quantitative methods and compared. The capillary endothelial cells in the ventromedial nucleus were used as an index of blood-brain barrier endothelium in cerebral gray matter; this endothelium has relatively low surface area and low permeability to tracer solutes. The permeability X surface area product of endothelial cells for a neutral amino acid, 14C-alpha-aminoisobutyric acid (AIB), in the ventromedial nucleus was similar to the value for supraoptic nucleus and was several hundred times smaller than in the neural lobe. The supraoptic nuclei and neural lobe had exceptionally large capillary surface areas, but dissimilar rates of blood flow and transendothelial influx of AIB. Differences in permeability of the endothelial cells between these two structures correlated closely with their marked dissimilarities in morphology. The neural lobe endothelium had numerous fenestrations (five per capillary cross-section) and vesicular profiles (twice as many as supraoptic nucleus), two features commonly associated with high capillary permeability. The capillary endothelium of the supraoptic nucleus was that of a typical blood-brain barrier structure having intercellular junctions that appeared tight, no fenestrations, and few cytoplasmic pits and vesicles. The unusually large capillary surface area of the supraoptic nucleus and low rate of solute flux across its endothelial cells make this nucleus a unique structure in which rapid changes in tissue volume may occur in response to small perturbations in plasma osmolality. The findings implicate the supraoptic nucleus as an osmotically sensitive detector or 'osmometer' in neuroendocrine regulation of body fluid homeostasis.


Assuntos
Neuro-Hipófise/irrigação sanguínea , Núcleo Supraóptico/irrigação sanguínea , Equilíbrio Hidroeletrolítico , Animais , Barreira Hematoencefálica , Capilares/anatomia & histologia , Permeabilidade Capilar , Endotélio/ultraestrutura , Masculino , Microscopia Eletrônica , Ratos , Ratos Endogâmicos , Núcleo Hipotalâmico Ventromedial/fisiopatologia
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