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1.
Zhonghua Nei Ke Za Zhi ; 62(4): 374-383, 2023 Apr 01.
Artigo em Chinês | MEDLINE | ID: mdl-37032132

RESUMO

Objectives: To investigated the safety and efficacy of treating patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) and elevated levels of N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) with levosimendan within 24 hours of first medical contact (FMC). Methods: This multicenter, open-label, block-randomized controlled trial (NCT03189901) investigated the safety and efficacy of levosimendan as an early management strategy of acute heart failure (EMS-AHF) for patients with NSTEMI and high NT-proBNP levels. This study included 255 patients with NSTEMI and elevated NT-proBNP levels, including 142 males and 113 females with a median age of 65 (58-70) years, and were admitted in the emergency or outpatient departments at 14 medical centers in China between October 2017 and October 2021. The patients were randomly divided into a levosimendan group (n=129) and a control group (n=126). The primary outcome measure was NT-proBNP levels on day 3 of treatment and changes in the NT-proBNP levels from baseline on day 5 after randomization. The secondary outcome measures included the proportion of patients with more than 30% reduction in NT-proBNP levels from baseline, major adverse cardiovascular events (MACE) during hospitalization and at 6 months after hospitalization, safety during the treatment, and health economics indices. The measurement data parameters between groups were compared using the t-test or the non-parametric test. The count data parameters were compared between groups using the χ² test. Results: On day 3, the NT-proBNP levels in the levosimendan group were lower than the control group but were statistically insignificant [866 (455, 1 960) vs. 1 118 (459, 2 417) ng/L, Z=-1.25,P=0.21]. However, on day 5, changes in the NT-proBNP levels from baseline in the levosimendan group were significantly higher than the control group [67.6% (33.8%,82.5%)vs.54.8% (7.3%,77.9%), Z=-2.14, P=0.03]. There were no significant differences in the proportion of patients with more than 30% reduction in the NT-proBNP levels on day 5 between the levosimendan and the control groups [77.5% (100/129) vs. 69.0% (87/126), χ²=2.34, P=0.13]. Furthermore, incidences of MACE did not show any significant differences between the two groups during hospitalization [4.7% (6/129) vs. 7.1% (9/126), χ²=0.72, P=0.40] and at 6 months [14.7% (19/129) vs. 12.7% (16/126), χ²=0.22, P=0.64]. Four cardiac deaths were reported in the control group during hospitalization [0 (0/129) vs. 3.2% (4/126), P=0.06]. However, 6-month survival rates were comparable between the two groups (log-rank test, P=0.18). Moreover, adverse events or serious adverse events such as shock, ventricular fibrillation, and ventricular tachycardia were not reported in both the groups during levosimendan treatment (days 0-1). The total cost of hospitalization [34 591.00(15 527.46,59 324.80) vs. 37 144.65(16 066.90,63 919.00)yuan, Z=-0.26, P=0.80] and the total length of hospitalization [9 (8, 12) vs. 10 (7, 13) days, Z=0.72, P=0.72] were lower for patients in the levosimendan group compared to those in the control group, but did not show statistically significant differences. Conclusions: Early administration of levosimendan reduced NT-proBNP levels in NSTEMI patients with elevated NT-proBNP and did not increase the total cost and length of hospitalization, but did not significantly improve MACE during hospitalization or at 6 months.


Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio sem Supradesnível do Segmento ST , Masculino , Feminino , Humanos , Idoso , Peptídeo Natriurético Encefálico , Simendana/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Fragmentos de Peptídeos , Arritmias Cardíacas , Biomarcadores , Prognóstico
2.
Zhonghua Xin Xue Guan Bing Za Zhi ; 50(9): 873-880, 2022 Sep 24.
Artigo em Chinês | MEDLINE | ID: mdl-36096704

RESUMO

Objective: To compare the clinical features and the outcome of in-hospital mortality between patients with myocardial infarction with non-obstructive coronary arteries(MINOCA)and myocardial infarction with obstructive coronary artery disease (MI-CAD). Methods: This is a retrospective study. The clinical data of acute myocardial infarction (AMI) patients admitted to Qilu Hospital of Shandong University from January 2017 to May 2021, who underwent coronary angiography, were collected. Patients were divided into MINOCA group and MI-CAD group according to the degree of coronary stenosis (<50% or ≥50%). Baseline clinical characteristics, electrocardiograph during hospitalization, myocardial bridge, length of stay in hospital, discharge medication and the outcome of in-hospital mortality were collected and compared between the two groups. Univariate and multivariate logistic regression analysis was used to screen the related factors of MINOCA and the factors predicting the nosocomial death outcome of patients with AMI. Results: A total of 3 048 AMI patients were enrolled, age was 62 (54, 69) years, 741 (24.3%) patients were women including 165 patients (5.4%) in the MINOCA group and 2 883 patients (94.6%) in the MI-CAD group. Compared with MI-CAD patients, MINOCA patients were younger, had a higher proportion of females and a higher incidence of NSTEMI, and had a lower history of smoking, diabetes, coronary heart disease and myocardial infarction. Baseline inflammatory markers such as neutrophil count, monocyte count, neutrophil count/lymphocyte count (NLR), and monocyte count/high-density lipoprotein count (MHR) were lower, creatinine, N-terminal pro-brain B-type Natriuretic peptides (NT-proBNP), creatine kinase-MB, hypersensitive troponin I, fibrinogen, baseline blood glucose levels were lower, high-density lipoprotein cholesterol was higher, and the incidence of myocardial bridge, arrhythmia, tachycardia and atrial fibrillation was higher (P<0.05). The application rates of calcium antagonists and non-vitamin K antagonists oral anticoagulants were higher in MINOCA group (P<0.05), and there was no statistical difference in hospitalization days and in-hospital death between the two groups (P>0.05). Multiple logistic regression analysis showed that young age, female, non-smoker, no history of coronary heart disease and low MHR were risk factors of MINOCA (P<0.05). MINCOA was not associated with higher in-hospital death (P>0.05). Patients with AMI and a history of coronary heart disease, chronic renal failure, higher baseline blood glucose, higher NLR, and higher D-dimer were risk factors of in-hospital death (P<0.05). Conclusions: Compared with MI-CAD patients, MINOCA patients are younger, more likely to be female and non-smokers and on history of coronary heart disease, and have lower baseline MHR. MINOCA is often associated with myocardial bridge and atrial fibrillation. The incidence of in-hospital death in MINCOA patients is similar as in MI-CAD patients.


Assuntos
Fibrilação Atrial , Doença da Artéria Coronariana , Infarto do Miocárdio , Fibrilação Atrial/complicações , Glicemia , Doença da Artéria Coronariana/complicações , Feminino , Mortalidade Hospitalar , Humanos , Lipoproteínas HDL , MINOCA , Masculino , Infarto do Miocárdio/complicações , Estudos Retrospectivos
3.
Curr Mol Med ; 12(3): 316-30, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22300136

RESUMO

In recent years, more and more mutant genes that cause retinal diseases have been detected. At the same time, many naturally occurring mouse models of retinal degeneration have also been found, which show similar changes to human retinal diseases. These, together with improved viral vector quality allow more and more traditionally incurable inherited retinal disorders to become potential candidates for gene therapy. Currently, the most common vehicle to deliver the therapeutic gene into target retinal cells is the adenoassociated viral vector (AAV). Following delivery to the immuno-privileged subretinal space, AAV-vectors can efficiently target both retinal pigment epithelium and photoreceptor cells, the origin of most retinal degenerations. This review focuses on the AAV-based gene therapy in mouse models of recessive retinal degenerations, especially those in which delivery of the correct copy of the wild-type gene has led to significant beneficial effects on visual function, as determined by morphological, biochemical, electroretinographic and behavioral analysis. The past studies in animal models and ongoing successful LCA2 clinical trials, predict a bright future for AAV gene replacement treatment for inherited recessive retinal diseases.


Assuntos
Dependovirus/genética , Terapia Genética/métodos , Vetores Genéticos/genética , Degeneração Retiniana/terapia , Animais , Modelos Animais de Doenças , Camundongos
4.
Vision Res ; 46(22): 3926-34, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16814838

RESUMO

One eye of rd12 mice received a sub-retinal injection of a vector carrying normal human RPE65 cDNA at post-natal day 18, and at 6- and 13-months of age. Electroretinograms (ERGs) and visual-evoked potentials (VEPs) were recorded to luminance, and to spatially and temporally modulated stimuli to assess the consequences of delayed treatment on visual pathway function. Early treatment resulted in better overall retinal rescue and better rescue of cone-mediated function. VEPs to low temporal frequency luminance modulation were well preserved at all but the oldest treatment age and corresponded to predictions based on the amount of retinal rescue. In contrast, VEPs to high frequency spatially and temporally modulated stimuli were impaired even at the earliest age. These results provide further support that early treatment in human LCA will have the most hope for optimal visual performance.


Assuntos
Cegueira/genética , Terapia Genética/métodos , Retina/fisiopatologia , Córtex Visual/fisiopatologia , Animais , Cegueira/congênito , Cegueira/fisiopatologia , Adaptação à Escuridão , Modelos Animais de Doenças , Eletrorretinografia/métodos , Potenciais Evocados Visuais/fisiologia , Camundongos , Camundongos Mutantes , Rodopsina/metabolismo , Fatores de Tempo , Testes Visuais/métodos , Acuidade Visual/fisiologia
5.
Mol Cell Biochem ; 275(1-2): 57-66, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16335784

RESUMO

We have previously shown that the partial disruption of the gene for atrial natriuretic peptide (ANP) results in a salt-sensitive phenotype. The present study examined the possibility that alterations in either the ANP natriuretic pathway or endothelin (ET) system in the kidney of the salt-challenged ANP +/- mouse was responsible for its salt-sensitive phenotype. Plasma ANP levels and renal cGMP activity were increased in response to a salt load in both ANP +/+ and +/- mice. However, the mRNA expression of proANP was found to be increased only in the ANP +/- kidney along with its guanylyl cyclase-linked receptor, NPRA; the upregulation of NPRA mRNA was limited to the renal medulla. This suggests that the renal ANP pathway remains capable of responding to a salt load in the ANP +/- animal, but may be compensating for other dysfunctional pathways. We also report a significant increase in renal ET-1 mRNA and ETA receptor protein expression in medulla and cortex of the salt-treated, ANP +/- mouse, but not its wild-type counterpart. In fact, ETA expression decreased in the renal cortex of the ANP +/+ salt-treated animal. The ETB receptor expression was not affected by diet in either genotype. We hypothesize that the salt-sensitive hypertension in the ANP +/- mouse is exacerbated, and possibly driven by the vasoconstrictive effects resulting from an upregulated ET-1/ETA pathway.


Assuntos
Fator Natriurético Atrial/genética , Fator Natriurético Atrial/fisiologia , Hipertensão/fisiopatologia , Receptor de Endotelina A/fisiologia , Sódio na Dieta , Animais , Fator Natriurético Atrial/sangue , Western Blotting , GMP Cíclico/análise , Modelos Animais de Doenças , Guanilato Ciclase/fisiologia , Heterozigoto , Homozigoto , Hipertensão/genética , Rim/química , Rim/fisiologia , Camundongos , Camundongos Knockout , RNA Mensageiro/análise , Receptores de Enterotoxina , Receptores Acoplados a Guanilato Ciclase , Receptores de Peptídeos/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima
6.
Mol Vis ; 11: 648-56, 2005 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-16145542

RESUMO

PURPOSE: To develop a hammerhead ribozymes (Rz) that might be exploited in a "digest and replace" gene therapy strategy for autosomal dominant retinitis pigmentosa (ADRP) caused by mutations in the gene for rhodopsin (RHO). METHODS: A ribozyme (Rz397) was designed to hybridize with an accessible region in rhodopsin mRNA. It was tested in vitro to determine the kinetics of cleavage of a target oligonucleotide. Following transfection of cultured cells, reduction of rhodopsin mRNA in response to Rz397 was measured RT-PCR. The gene for the ribozyme (Rz397) was inserted in an adeno-associated virus (AAV2) vector and packaged in AAV2 capsids. The virus was injected subretinally in the eyes of C57BL/6J (RHO+/+) and rhodopsin knockout hemizygous (RHO+/-) mice at postnatal days 6 (P6) and 30 (P30). Mice were analyzed by full-field electroretinography (ERG). The reduction of opsin protein was measured by western blot analysis and visualized by immunocytochemistry. Reduction of rhodopsin mRNA was assessed using in situ hybridization. Morphometric microscopy of fluorescent antibody-antigen complexes and autoradiography of retinas were used to quantify levels of rhodopsin protein and mRNA, respectively. RESULTS: Transient co-transfection of HEK 293 cells with a wild-type rhodopsin cDNA and Rz397 resulted in an approximately 60% reduction of RHO mRNA one day after transfection. RHO+/- -mice injected with AAV2-Rz397 at P6 showed a 50% reduction in b-wave amplitudes in injected eyes relative to saline injected contralateral eyes. However, injection of RHO+/- -animals at one month and of RHO+/+-animals at either age had no impact on ERG. Nevertheless, we detected an 80% reduction of opsin protein in ribozyme-injected eyes of hemizygous mice (by western blot) and a 50% reduction in opsin content in RHO+/+ mice (by morphometry). These reductions were confirmed by in situ hybridization. CONCLUSIONS: AAV2-Rz397 led to significant (greater than or equal to 50%) reduction of rhodopsin mRNA and protein in mice. It affected ERG amplitudes only when injected in hemizygous RHO knockout pups. This RNA inhibitor may prove useful in treating animal models of ADRP as part of an RNA replacement approach.


Assuntos
Dependovirus/genética , Terapia Genética , Vetores Genéticos , RNA Catalítico/genética , Retinose Pigmentar/terapia , Rodopsina/genética , Animais , Western Blotting , Células Cultivadas , Eletrorretinografia , Imuno-Histoquímica , Hibridização In Situ , Rim/citologia , Rim/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/metabolismo , Retinose Pigmentar/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rodopsina/metabolismo , Opsinas de Bastonetes/metabolismo , Transfecção
7.
Zhongguo Zhong Yao Za Zhi ; 26(5): 334-7, 2001 May.
Artigo em Chinês | MEDLINE | ID: mdl-12528525

RESUMO

OBJECTIVE: To investigate the effect of Curcuma zedoaria on the myoelectric activity of uterus in virgin rats and study its mech anisms. METHOD: A pair of bipolar Ag-AgCl electrodes were implanted on the serosal surface of uterus in rats to observe the effect of C. zedoaria on the myoelectric activity of uterus before and after the five agonists were injected intraperitoneally. RESULT: Decoction of C. zedoaria significantly increases the spike area, the duration and the number of bursts of action potentials of the uterine smooth muscle and its effect is related dosage. Atropine and phentolamine decreased the exciting effect of C. zedoaria, whereas verapamil, diphenhydramine and indomethacin have no effect on the excitation of C. zedoaria. CONCLUSION: C. zedoaria has obvious exciting effect on the smooth muscle of uterus in rats, and its mechanisms may be associated with M-receptor and alpha-receptor.


Assuntos
Curcuma , Medicamentos de Ervas Chinesas/farmacologia , Músculo Liso/efeitos dos fármacos , Plantas Medicinais , Útero/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Animais , Feminino , Ratos , Ratos Wistar
8.
J Neurol Neurosurg Psychiatry ; 68(4): 521-5, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10727494

RESUMO

A new syndrome of ataxia and retinitis pigmentosa with vitamin E deficiency caused by the missense mutation of alpha-tocopherol transfer protein (alpha-TTP) gene was recently proposed. After studying the first postmortem case with this mutation pathologically and biochemically, whether the symptoms can be treated by supplementation of vitamin E or not is discussed. The major pathological findings were retinal atrophy; severe dying back-type degeneration of the posterior column; and massive accumulation of lipofuscin in neurons including dorsal root ganglion (DRG) cells, which were almost identical to those in vitamin E deficient animals and patients with fat malabsorption. Also, mild loss of Purkinje cells was noted. Because robust expression of alpha-TTP was detected in the cerebellum as well as in the liver and the tissue concentration of vitamin E in the cerebellum was still low even after oral supplementation, the mild Purkinje cell loss might be related to the mutant alpha-TTP in the cerebellum. By contrast, in the DRG, thought to be mainly responsible for ataxia, no expression of alpha-TTP was detected, and the tissue concentration of vitamin E increased to normal after supplementation. It is therefore considered that oral supplementation of vitamin E should effectively counteract the progression of ataxia.


Assuntos
Ataxia/genética , Ataxia/patologia , Proteínas de Transporte/genética , Retinose Pigmentar/genética , Retinose Pigmentar/patologia , Idoso , Humanos , Masculino , Mutação/genética
9.
Sheng Li Xue Bao ; 47(1): 100-4, 1995 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-7784892

RESUMO

The aging changes of the electrophysiological characteristics of the hypothalamic neurons cultured for 0-140 days were studied in neonatal SD rats by the intracellular microelectrode recording technique. The growth velocity of the neurites was used as an index to divide the living process of the neurons into three periods, i.e. recovering period, growth period and aging period. It was found that the time constant and the membrane capacitance reached a top value in the growth period and then decreased significantly in the aging period (P < 0.05, P < 0.01). In the recovering period, the membrane resistance reached the highest; and then decreased significantly in growth period but did not change significantly in the aging period. The amplitude of the membrane resting potential was about -30 - -60 mv and increased with the days in vitro (P < 0.05). The neurons could produce single or burst discharges. It appears that certain electrophysiological characteristics of the hypothalamic neurons in culture could characterize certain aging changes.


Assuntos
Hipotálamo/fisiologia , Animais , Animais Recém-Nascidos , Células Cultivadas , Senescência Celular/fisiologia , Potenciais Evocados , Hipotálamo/citologia , Microeletrodos , Neuritos/fisiologia , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley
10.
Neuropharmacology ; 33(10): 1155-66, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7862251

RESUMO

A comprehensive series of time-related behavioral, physiological and cerebral metabolic studies was conducted using conscious Sprague-Dawley rats to discern the anti-endothelin (ET) properties of the specific ETA receptor antagonist, FR139317. Endothelin-1 (9 pmol given by injection into one lateral ventricle, i.c.v.) produced convulsions, acute arterial hypertension, arterial hyperglycemia, and hyperventilation. Brain structures close to the i.c.v. site of injection, such as the caudate nucleus, lateral septal nucleus, corpus callosum and hippocampal CA3 medial lamellae, as well as 14 other individual structures, displayed moderate-to-intense levels of metabolic activation after endothelin. Data were assessed quantitatively by means of the autoradiographic [14C]deoxyglucose technique combined with image analysis. Neural circuits in the efferent projection paths of the stimulated forebrain structures, such as the midbrain oculomotor complex, amygdaloid nuclei, substantia nigra pars reticulata and caudal subicular subregions of the hippocampal formation, were stimulated focally by endothelin. Specific medullary nuclei and cerebellar cortical subregions displayed high rates of glucose metabolism following endothelin injection at the time of maximum behavioral and physiological stimulation. I.c.v. treatment with > or = 14 nmol FR139317 before endothelin significantly inhibited the effects produced by the peptide. At the highest dose of FR139317 (28 nmol), there was only mild behavioral stimulation following endothelin injection, and hypermetabolic responses in the brain were abolished except in two specific areas of the cerebellar cortex (approx 40% increases in metabolic activity in the copula pyramis and paramedian lobule). The results indicate that the cerebral stimulatory effects of i.c.v. endothelin are mediated by the A type of endothelin receptor. By itself, i.c.v. FR139317 had no effects on the parameters assessed. Further evaluation of FR139317 is warranted as a possible therapeutic agent for neuropathologies suspected of deriving from central neural or vascular stimulation by endothelin, such as aneurysmal vasospasm, ischemia, excitotoxicity, and peptide-mediated epilepsies.


Assuntos
Azepinas/farmacologia , Encéfalo/efeitos dos fármacos , Antagonistas dos Receptores de Endotelina , Endotelinas/antagonistas & inibidores , Indóis/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Endotelinas/administração & dosagem , Glucose/metabolismo , Injeções Intraventriculares , Masculino , Ratos , Ratos Sprague-Dawley
11.
Neuropharmacology ; 33(7): 915-27, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7969812

RESUMO

A solution containing S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide (NO.-releasing compound, was microinjected in doses of 0.25-2 mumol into a lateral ventricle of conscious rats. SNAP produced dose-dependent convulsions similar to those associated with limbic stimulation, such as tonic extension of the hindlimbs and tail, and dystonia of the forepaws. At 2 mumol, SNAP evoked hyperventilation (arterial hypocapnia), arterial hyperglycemia and caused necrotic lesions of periventricular gray (e.g. lateral septal nucleus) and white matter structures. In the caudate nucleus and lateral septal nucleus ipsilateral to injection, SNAP elicited a bipolar metabolic pattern of low glucose metabolism proximal to the ventricle with higher values occurring more distally. In control studies, we proved that the residue of SNAP decomposition, N-acetylpenicillamine disulfide injected intraventricularly (2 mumol), was without physiological, behavioral, or histological effects. Ventricular pretreatment with methylene blue (2 nmol), a putative inhibitor of guanylate cyclase and superoxide generator, suppressed several of the behavioral manifestations of 1 mumol SNAP, such as the forepaw dystonia, squinting, and facial clonus, but was ineffective on the physiological and histological variables affected by the 2 mumol SNAP dose. Another NO. donor, sodium nitroprusside (2 mumol), produced fewer behavioral and cytotoxic effects over a 55-min observation period, but caused more intense and widely distributed metabolic stimulation, especially in commissural and projection white matter tracts. The results are the basis for a conscious rat model using intraventricular injection of nitrocompounds to examine the physiological, behavioral, metabolic and cytotoxic properties of NO. in the brain.


Assuntos
Doenças do Sistema Nervoso/induzido quimicamente , Óxido Nítrico/metabolismo , Penicilamina/análogos & derivados , Equilíbrio Ácido-Base/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Análise Química do Sangue , Encéfalo/enzimologia , Encéfalo/patologia , Química Encefálica/efeitos dos fármacos , Guanilato Ciclase/antagonistas & inibidores , Hemodinâmica/efeitos dos fármacos , Injeções Intraventriculares , Masculino , Azul de Metileno/administração & dosagem , Azul de Metileno/farmacologia , Doenças do Sistema Nervoso/patologia , Doenças do Sistema Nervoso/fisiopatologia , Nitroprussiato/administração & dosagem , Nitroprussiato/farmacologia , Penicilamina/administração & dosagem , Penicilamina/toxicidade , Ratos , Ratos Sprague-Dawley , S-Nitroso-N-Acetilpenicilamina
12.
Cell Tissue Res ; 272(1): 79-88, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8481959

RESUMO

We applied scanning electron microscopy combined with imaging and morphometric techniques to analyze the dorsal topography and morphology of short portal vessels linking the capillary beds of the pituitary neural and anterior lobes in adult male albino rats. The pituitary microvasculature was replicated by intracarotid injection of Batson's No. 17 compound producing plastic casts that were advantageous for comprehensive morphometric analyses using an imaging device. The analysis revealed the existence of two types of portal vessels having quantitatively different morphological properties. The bilateral venular plexus of 3-4 vessels located at the base of the infundibular stalk (each venule measuring 300 microns in length and 32 microns in diameter) appears to be the major part of the short portal system in the dorsum of the rat pituitary gland. Narrower capillary-like shunt vessels (6.8 microns in diameter), of about the same length as the venules, were situated throughout other subregions of the intermediate lobe cleft. The short portal vessels of both types made direct anastomoses with the capillary networks in the neural and anterior lobes. The neural lobe capillaries were twice as numerous (1324 per mm2), and only half as wide (6.2 microns), as the sinusoidal capillaries in the anterior lobe (density of 637 per mm2; diameter of 13.7 microns). The topographical position of the portal venular system suggests that the caudolateral subregions of the pituitary neural and anterior lobes have a functional relationship dependent on rapid interlobe transfer of neurohumoral factors such as hormones via the portal blood. This process appears to be supplemented throughout the rest of the cleft between the two lobes by a small number of capillary shunts that supply the epithelial cell lobules of the intermediate lobe in situ. The findings collectively indicate that this portal system provides a constant stream of neurohumoral information that is shared moment-by-moment between the pituitary neural and anterior lobes.


Assuntos
Hipófise/irrigação sanguínea , Sistema Porta/ultraestrutura , Animais , Capilares/ultraestrutura , Molde por Corrosão , Masculino , Metilmetacrilato , Metilmetacrilatos , Microcirculação , Microscopia Eletrônica de Varredura , Hipófise/ultraestrutura , Ratos , Ratos Sprague-Dawley , Vênulas/ultraestrutura
13.
Cell Tissue Res ; 267(3): 437-48, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1571958

RESUMO

The differentiated cytology, cytochemistry, and functions within subdivisions of the tuber cinereum prompted this morphometric and physiological investigation of capillaries in the medium eminence and arcuate nucleus of albino rats. Morphometric studies established that the external zone of the median eminence had 3-5 times the number and surface area of true and sinusoidal capillaries than the internal or subependymal median eminence zones, or either of two subdivisions examined in the arcuate nucleus. Type-I true capillaries, around which Virchow-Robin spaces comprise 1% of arcuate tissue area, were situated proximally to the median eminence border. This finding is consistent with a premise that confluent pericapillary spaces enable infiltration of arcuate neurons by factors from capillary blood from the median eminence or Virchow-Robin spaces. Physiologically, the rate of penetration across the median eminence capillaries by blood-borne [14C]alpha-amino-isobutyric acid (a neutral amino acid used as a capillary permeability tracer) was 142 times greater than for capillaries in the distal arcuate nucleus within 12 s of tracer administration. A new finding was that the proximal arcuate nucleus had a permeability x surface area product of 69 microliters g-1 min-1, 34 times greater than that in more distal aspects of the tuber where blood-brain barrier properties exist. We also found that the microcirculatory transit time of a plasma space marker, [14C]sucrose, was considerably longer (1.2 s) in the median eminence and proximal arcuate nucleus than in the distal arcuate or ventromedial nucleus (0.4 s). By virtue of its high capillary permeability and extensive blood-tissue surface area, including the wide Virchow-Robin spaces, the median eminence external zone could be a gateway for flooding other tuberal compartments with blood-borne factors. This effect may be compounded by capillary bed specializations in the proximal arcuate nucleus where Type-I true capillaries, Type-III sinusoids, and pericapillary spaces are confluent with those in the median eminence. The results indicate that the proximal arcuate parenchyma could be exposed to circulating neuroactive substances on a moment-to-moment basis.


Assuntos
Capilares/fisiologia , Capilares/ultraestrutura , Túber Cinéreo/irrigação sanguínea , Animais , Núcleo Arqueado do Hipotálamo/irrigação sanguínea , Núcleo Arqueado do Hipotálamo/ultraestrutura , Autorradiografia , Masculino , Matemática , Eminência Mediana/irrigação sanguínea , Eminência Mediana/ultraestrutura , Microscopia Eletrônica , Ratos , Ratos Endogâmicos , Túber Cinéreo/ultraestrutura
14.
J Comp Neurol ; 306(1): 73-82, 1991 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-2040730

RESUMO

Cytoarchitectonic and neurochemical studies of the dorsal vagal complex in the caudal medulla oblongata of rats indicate the existence of distinct anatomical and functional compartments within its components. We applied morphometric methods to discern whether capillary networks differed quantitatively between subregions and zones of area postrema, nucleus tractus solitarii (NTS), and dorsal motor nucleus of the vagus nerve (DMN) of rats. Analysis of 11 subdivisions of area postrema identified both "true" (range in luminal diameter of 3-7.5 microns) and sinusoidal (luminal diameter greater than 7.5 microns) capillaries that, together, made the capillary density for most of area postrema 75% greater than that found in NTS and DMN (526/mm2 vs about 300/mm2). The rank order of true capillary density in area postrema along its rostracaudal axis was caudal greater than central greater than rostral, whereas the reverse order was true for sinusoidal capillaries. Dorsal (periventricular) and medial zones of area postrema throughout its rostrocaudal axis tended to have higher values for capillary density, volume, surface area, luminal diameter, and pericapillary space volume than lateral or ventral zones bordering NTS. Within 200 microns of obex, the ventral zone of rostral area postrema was distinct, having a relatively sparse capillary density that may indicate morphological specializations limiting blood-tissue communication in this subregion. There were no quantitative differences in capillary dimensions between DMN and three subnuclei of NTS. These studies add to extant evidence that the dorsal vagal complex is differentiated for specific functions. Area postrema, especially, has topographical diversity in its capillary organization that likely corresponds to complex roles in neuroendocrine, autonomic, and chemosensory mechanisms.


Assuntos
Bulbo/irrigação sanguínea , Ratos/anatomia & histologia , Nervo Vago/anatomia & histologia , Animais , Capilares/anatomia & histologia , Masculino , Bulbo/fisiologia , Ratos/fisiologia , Ratos Endogâmicos , Nervo Vago/fisiologia
15.
Am J Physiol ; 259(6 Pt 2): R1131-8, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2260724

RESUMO

Nucleus tractus solitarius (NTS), an aggregate of several individual nuclear groups in the dorsal medulla oblongata, is involved in virtually all autonomic functions as the first synaptic site in the brain for many peripheral viscerosomatic inputs. We found morphological evidence that dorsocaudal subregions of rat NTS (approximately 800 microns caudal from obex) had fenestrated capillaries and enlarged Virchow-Robin (perivascular) spaces that were similar to those in area postrema but unlike capillaries elsewhere in the medulla oblongata. Complexes of microvessels, consisting of up to 10 small vessels with smooth muscle layers (luminal diameters of 10-45 microns) and several capillaries (average luminal diameter of 4.5 microns), were located in the dorsal midline of NTS within large Virchow-Robin spaces measuring some 2,000 microns 2 in area. In physiological studies, we determined that most of NTS had a definable blood-brain barrier [permeability-surface area (PS) products for a neutral amino acid near 0], but medial and lateral aspects of the commissural subnucleus of NTS had PS products of 16-63 microliters.g-1.min-1 for alpha-[14C]aminoisobutyric acid 12 s after intravenous injection. Microvascular differentiations permitting such brisk tracer influx from blood resemble those of area postrema and appear to afford the rich neuropil of commissural NTS with a constant stream of blood-borne information for expediting its regulation of viscerosensory and autonomic functions.


Assuntos
Capilares/metabolismo , Espaço Extracelular/metabolismo , Bulbo/metabolismo , Ácidos Aminoisobutíricos/metabolismo , Animais , Autorradiografia , Barreira Hematoencefálica , Capilares/ultraestrutura , Permeabilidade Capilar , Ventrículos Cerebrais/irrigação sanguínea , Ventrículos Cerebrais/metabolismo , Ventrículos Cerebrais/ultraestrutura , Masculino , Bulbo/irrigação sanguínea , Microscopia Eletrônica , Ratos , Ratos Endogâmicos
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