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1.
Ann Thorac Surg ; 118(2): 338-351, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38864803

RESUMEN

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Sociedades Médicas , Cirugía Torácica , Humanos , Países en Desarrollo , Salud Global
2.
J Thorac Cardiovasc Surg ; 168(4): e104-e116, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38864805

RESUMEN

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programs that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of "assisting only." In Rwanda, Team Heart, a US and Rwanda-based nongovernmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its "Seal of Approval" for the sustainability of endorsed programs in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programs could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Sociedades Médicas , Humanos , Países en Desarrollo , Cirugía Torácica/organización & administración , Cirugía Torácica/educación , Cooperación Internacional , Accesibilidad a los Servicios de Salud/organización & administración , Conducta Cooperativa
3.
Asian Cardiovasc Thorac Ann ; 32(5): 271-284, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38872357

RESUMEN

SUMMARY: Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, it's 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Países en Desarrollo , Sociedades Médicas , Humanos , Creación de Capacidad/organización & administración , Conducta Cooperativa , Accesibilidad a los Servicios de Salud/organización & administración , Necesidades y Demandas de Servicios de Salud/organización & administración , Disparidades en Atención de Salud , Cooperación Internacional , Sociedades Médicas/organización & administración , Cirugía Torácica/organización & administración , Cirugía Torácica/educación , Factores de Tiempo
4.
Eur J Cardiothorac Surg ; 65(6)2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38856237

RESUMEN

Informed by the almost unimaginable unmet need for cardiac surgery in the developing regions of the world, leading surgeons, cardiologists, editors in chief of the major cardiothoracic journals as well as representatives of medical industry and government convened in December 2017 to address this unacceptable disparity in access to care. The ensuing "Cape Town Declaration" constituted a clarion call to cardiac surgical societies to jointly advocate the strengthening of sustainable, local cardiac surgical capacity in the developing world. The Cardiac Surgery Intersociety Alliance (CSIA) was thus created, comprising The Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), the Asian Society for Cardiovascular and Thoracic Surgery (ASCVTS), the European Association for Cardio-Thoracic Surgery (EACTS) and the World Heart Federation (WHF). The guiding principle was advocacy for sustainable cardiac surgical capacity in low-income countries. As a first step, a global needs assessment confirmed rheumatic heart disease as the overwhelming pathology requiring cardiac surgery in these regions. Subsequently, CSIA published a request for proposals to support fledgling programmes that could demonstrate the backing by their governments and health care institution. Out of 11 applicants, and following an evaluation of the sites, including site visits to the 3 finalists, Mozambique and Rwanda were selected as the first Pilot Sites. Subsequently, a mentorship and training agreement was completed between Mozambique and the University of Cape Town, a middle-income country with a comparable burden of rheumatic heart disease. The agreement entails regular video calls between the heart teams, targeted training across all aspects of cardiac surgery, as well as on-site presence of mentoring teams for complex cases with the strict observance of 'assisting only'. In Rwanda, Team Heart, a US and Rwanda-based non-governmental organization (NGO) that has been performing cardiac surgery in Rwanda and helping to train the cardiac surgery workforce since 2008, has agreed to continue providing mentorship for the local team and to assist in the establishment of independent cardiac surgery with all that entails. This involves intermittent virtual conferences between Rwandan and US cardiologists for surgical case selection. Five years after CSIA was founded, its 'Seal of Approval' for the sustainability of endorsed programmes in Mozambique and Rwanda has resulted in higher case numbers, a stronger government commitment, significant upgrades of infrastructure, the nurturing of generous consumable donations by industry and the commencement of negotiations with global donors for major grants. Extending the CSIA Seal to additional deserving programmes could further align the international cardiac surgical community with the principle of local cardiac surgery capacity-building in developing countries.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Sociedades Médicas , Cirugía Torácica , Humanos , Sociedades Médicas/organización & administración , Cirugía Torácica/organización & administración , Países en Desarrollo , Salud Global
5.
Int J Pharm ; 307(1): 51-5, 2006 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-16257155

RESUMEN

Previous studies have confirmed that the phase transition of vesicular gels of hydrogenated phospholipids to the less ordered fluid vesicular state was induced by the increase of the beta-sitosterol ratio in the whole gel system and consequently in the lipid bilayer. The purpose of the present study was to evaluate the influence of the beta-sitosterol portion in the lipid bilayer and the effect of high pressure homogenization on the structural characteristics of the prepared gel systems. In addition the influence of beta-sitosterol on the consequent chlorhexidine release from the obtained vesicles and liposomes was also examined. Lipid mixtures were prepared from different molar ratios of lecithin:sterol components (90:10-65:35 mol%). The obtained mixtures were hydrated with the aqueous solution of chlorhexidine digluconate in order to achieve a 30% (w/w) final concentration of the lipid mixtures and a 4% (w/w) concentration of the drug. One portion of the resultant multilamellar vesicles was homogenized by using high pressure. To characterize the homogenized and non-homogenized systems, transmission electron microscopy of the freeze-fractured samples and differential scanning calorimetry (DSC) were carried out. A vertical type diffusion cell was applied to determine the amount of released chlorhexidine digluconate. Along with the increase in beta-sitosterol concentration, the fluidity of the membrane as well as its permeability also increased. The increased permeability--caused by the higher beta-sitosterol concentration--and the high pressure homogenization, which increased the dispersity and therefore the surface area, enabled a higher amount of chlorhexidine to be released. The increase of drug release was more pronounced in the case of samples prepared with high pressure homogenization.


Asunto(s)
Antiinfecciosos Locales/química , Clorhexidina/química , Composición de Medicamentos/métodos , Hipolipemiantes/química , Liposomas , Sitoesteroles/química , Rastreo Diferencial de Calorimetría , Preparaciones de Acción Retardada , Geles , Membrana Dobles de Lípidos/química , Microscopía Electrónica de Transmisión
6.
Prog Neurobiol ; 64(6): 575-611, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11311463

RESUMEN

The aging of the central nervous system and the development of incapacitating neurological diseases like Alzheimer's disease (AD) are generally associated with a wide range of histological and pathophysiological changes eventually leading to a compromised cognitive status. Although the diverse triggers of the neurodegenerative processes and their interactions are still the topic of extensive debate, the possible contribution of cerebrovascular deficiencies has been vigorously promoted in recent years. Various forms of cerebrovascular insufficiency such as reduced blood supply to the brain or disrupted microvascular integrity in cortical regions may occupy an initiating or intermediate position in the chain of events ending with cognitive failure. When, for example, vasoconstriction takes over a dominating role in the cerebral vessels, the perfusion rate of the brain can considerably decrease causing directly or through structural vascular damage a drop in cerebral glucose utilization. Consequently, cerebral metabolism can suffer a setback leading to neuronal damage and a concomitant suboptimal cognitive capacity. The present review focuses on the microvascular aspects of neurodegenerative processes in aging and AD with special attention to cerebral blood flow, neural metabolic changes and the abnormalities in microvascular ultrastructure. In this context, a few of the specific triggers leading to the prominent cerebrovascular pathology, as well as the potential neurological outcome of the compromised cerebral microvascular system are also going to be touched upon to a certain extent, without aiming at total comprehensiveness. Finally, a set of animal models are going to be presented that are frequently used to uncover the functional relationship between cerebrovascular factors and the damage to neural networks.


Asunto(s)
Envejecimiento/fisiología , Enfermedad de Alzheimer/patología , Encéfalo/irrigación sanguínea , Circulación Cerebrovascular/fisiología , Envejecimiento/metabolismo , Envejecimiento/patología , Enfermedad de Alzheimer/metabolismo , Animales , Membrana Basal/metabolismo , Membrana Basal/patología , Membrana Basal/ultraestructura , Barrera Hematoencefálica/fisiología , Encéfalo/patología , Capilares/metabolismo , Capilares/patología , Capilares/ultraestructura , Fibras Colinérgicas/metabolismo , Cognición/fisiología , Humanos , Aprendizaje/fisiología , Microcirculación/metabolismo , Microcirculación/patología , Microcirculación/ultraestructura
7.
Fitoterapia ; 76(2): 166-72, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15752626

RESUMEN

The transfer through a membrane of the main organic components and mineral elements of Carum carvi and Foeniculum vulgare volatile oils was studied. The transfer was studied from buffer solution pH 1.1 (stomach) and pH 6.5 (intestine) to pH 7.5 (plasma) in a Sartorius model. The transferred components were measured by GC-MS for volatile components and ICP-OES for inorganic elements. The main components (trans-anethole and fenchone from F. vulgare, carvone and D-limonene from C. carvi), as well as some mineral elements (Ca, Mg, S, Zn), transferred through the membrane.


Asunto(s)
Carum , Foeniculum , Mucosa Gástrica/metabolismo , Mucosa Intestinal/metabolismo , Fitoterapia , Aceites de Plantas/farmacocinética , Cromatografía de Gases y Espectrometría de Masas , Humanos
8.
Endocrinology ; 128(4): 1754-62, 1991 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1672273

RESUMEN

To investigate cAMP-dependent regulation of somatostatin secretion and gene expression in the islets of Langerhans, we have correlated the effects of forskolin, theophylline, and (Bu)2cAMP (dbcAMP) on the secretion of somatostatin-like immunoreactivity (SLI), cAMP generation, and somatosatin mRNA (S-mRNA) accumulation by cultured rat islet cells and a rat somatostatin-producing islet tumor cell line (1027 B2). Additionally, we have compared these effects with those of phorbol esters. Forskolin induced large acute increases in cAMP levels in islet cells, whereas theophylline produced modest sustained elevations in cAMP. During 4-h exposure to islets cells, forskolin, theophylline, and dbcAMP produced time- and dose-related increases of up to 14-fold in SLI release and up to 5-fold in S-mRNA levels. The rate of increase in S-mRNA paralleled secretion and occurred with the following order of potency: forskolin greater than dbcAMP greater than theophylline. The analog 1,9-dideoxyforskolin, which is unable to activate adenylyl cyclase, produced a small increase in SLI release without affecting S-mRNA. The effects of short term increases in islet cAMP levels and SLI release on long term changes in S-mRNA accumulation were investigated in a 48-h study with forskolin. Pretreatment of islet cells for 30 min with forskolin evoked large acute increases in cAMP levels and SLI release. S-mRNA rose in a biphasic pattern, with an acute increase at 30 min followed by a secondary increase at 12-48 h. In 1027B2 cells, forskolin and theophylline generated large increases in cAMP levels. Despite this, the two agents as well as dbcAMP produced only slight (20-35%) stimulation of SLI release and S-mRNA accumulation. Phorbol 12-myristate 13-acetate and phorbol 12,13-dibutyrate evoked dose-dependent stimulation of SLI secretion of up to 4-fold from islet cells without altering S-mRNA. Both secretion and S-mRNA were unresponsive to phorbol esters in 1027 B2 cells.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Adenoma de Células de los Islotes Pancreáticos/metabolismo , AMP Cíclico/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Ésteres del Forbol/farmacología , Somatostatina/metabolismo , Animales , Animales Recién Nacidos , Bucladesina/administración & dosificación , Bucladesina/farmacología , Colforsina/administración & dosificación , Colforsina/análogos & derivados , Colforsina/farmacología , Glucagón/metabolismo , Insulina/metabolismo , Secreción de Insulina , Islotes Pancreáticos/efectos de los fármacos , Cinética , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas , Somatostatina/genética , Teofilina/administración & dosificación , Teofilina/farmacología , Células Tumorales Cultivadas
9.
Neurobiol Aging ; 21(2): 235-43, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10867208

RESUMEN

Alzheimer's disease (AD) patients are often subject to vascular dysfunction besides their specific CNS pathology, which warrants further examination of the interaction between vascular factors and the development of dementia. The association of decreased cerebral blood flow (CBF) or hypertension with AD has been a target of growing interest. Parallel with physiological changes, the cerebral capillaries in AD are also prone to degenerative processes. The microvascular abnormalities that are the result of such degeneration may be the morphological correlates of the vascular pathophysiology pointing to a compromised nutrient transport through the capillaries. Animal models have been developed to study the consequences of hypertension and reduced CBF. Spontaneously hypertensive rats are widely used in hypertension research whereas ligation of the carotid arteries has become a method to produce cerebral hypoperfusion. Based on these models, we propose a relationship between hypertension, cerebral hypoperfusion, cerebral capillary malformation and cognitive decline as it occurs in AD. We suggest that the above conditions are functionally related and can contribute to the progression of AD.


Asunto(s)
Enfermedad de Alzheimer/patología , Circulación Cerebrovascular/fisiología , Hipertensión/patología , Anciano , Enfermedad de Alzheimer/etiología , Enfermedad de Alzheimer/fisiopatología , Animales , Capilares/patología , Humanos , Hipertensión/etiología , Hipertensión/fisiopatología , Persona de Mediana Edad , Ratas
10.
Neurobiol Aging ; 22(2): 299-309, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11182480

RESUMEN

Chronic hypertension during aging is a serious threat to the cerebral vasculature. The larger brain arteries can react to hypertension with an abnormal wall thickening, a loss of elasticity and a narrowed lumen. However, little is known about the hypertension-induced alterations of cerebral capillaries. The present study describes ultrastructural alterations of the cerebrocortical capillary wall, such as thickening and collagen accumulation in the basement membrane of aging spontaneously hypertensive stroke-prone rats. The ratio of cortical capillaries with such vascular pathology occurred significantly more frequently in hypertensive animals. Nimodipine and nifedipine are potential drugs to decrease blood pressure in hypertension but their beneficial effects in experimental studies reach beyond the control of blood pressure. Nimodipine and nifedipine can alleviate ischemia-related symptoms and improve cognition. These drugs differ in that nifedipine, but not nimodipine reduces blood pressure at the here-used concentration while both drugs can penetrate the blood-brain barrier. Here we show that chronic treatment of aging hypertensive stroke-prone rats with nimodipine or nifedipine could preserve microvascular integrity in the cerebral cortex.


Asunto(s)
Envejecimiento/patología , Bloqueadores de los Canales de Calcio/farmacología , Circulación Cerebrovascular/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Hipertensión/patología , Nimodipina/farmacología , Animales , Conducta Animal , Presión Sanguínea , Canales de Calcio Tipo L/metabolismo , Capilares/efectos de los fármacos , Capilares/patología , Capilares/ultraestructura , Ingestión de Líquidos , Ingestión de Alimentos , Conducta Exploratoria , Masculino , Microscopía Electrónica , Nifedipino/farmacología , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Accidente Cerebrovascular/tratamiento farmacológico , Accidente Cerebrovascular/patología
11.
Neuroscience ; 91(1): 203-10, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10336071

RESUMEN

The impact of chronic cerebral hypoperfusion on cognitive function and cerebral capillary morphology in the hippocampus was examined. Young adult Wistar rats were subjected to permanent ligation of both common carotid arteries (two-vessel occlusion). One month after vascular occlusion, a small but non-significant impairment in the acquisition of spatial information was registered compared with sham-operated controls. Two months after surgery, the occluded animals displayed an impaired performance throughout the training period. One year after surgery, the acquisition curves demonstrated a significant attenuation of the learning rate in the occluded rats group, whereas no significant differences in long-term retention were observed. Thus, chronic hypoperfusion induced by two-vessel occlusion gave rise to impairment of spatial memory. Following behavioural testing, the rats were killed at the age of 17 months, and capillaries in the CA1 and dentate gyrus were examined using transmission electron microscopy. Typical age-related capillary abnormalities such as degenerative pericytes and thickened basement membranes (with or without fibrosis) were detected in the hippocampus of sham animals. In occluded rats, the occurrence of capillaries displaying such abnormalities almost doubled in the CA1 region, but was similar in the dentate gyrus, compared with sham controls. A highly significant correlation was found between the last Morris maze performance and the percentage of capillaries with deposits in the basement membrane in the hippocampal CA1 area of occluded rats, which was not present in the sham animals. We conclude that a long-term hypoperfusion accelerated the development of age-related ultrastructural aberrations of capillaries in the hippocampal CA1 area, but not in the dentate gyrus. Thus, not only neurons, but also capillaries in the hippocampal CA1 area are sensitive to an impaired microcirculation. Moreover, the cognitive performance of hypoperfused rats correlated closely with the condition of the capillaries in the CA1 area, suggesting that capillary integrity is one of the important determinants of brain function in conditions that compromise cerebral microcirculation.


Asunto(s)
Isquemia Encefálica/patología , Isquemia Encefálica/psicología , Hipocampo/patología , Trastornos de la Memoria/patología , Trastornos de la Memoria/psicología , Percepción Espacial/fisiología , Animales , Capilares/patología , Capilares/ultraestructura , Circulación Cerebrovascular/fisiología , Hipocampo/ultraestructura , Masculino , Aprendizaje por Laberinto/fisiología , Microscopía Electrónica , Ratas , Ratas Wistar
12.
Ann N Y Acad Sci ; 903: 72-82, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10818491

RESUMEN

The brain, as an intensely active organ, is highly dependent on a sufficient nutrient and oxygen availability in order to reach its optimal working capacity. It is well known that the vital supply of energy substrates is provided by the circulatory system, which splits up into a fine, terminal capillary network in target tissues. These capillaries are considered as important sites, since the actual nutrient trafficking takes place through their walls. That is why an intact, preserved structure of the microvessels is crucial to fulfill their function. Since the brain is known to be particularly vulnerable to suboptimal oxygen and glucose delivery, the intact morphology of capillaries is of paramount importance. Several observations have indicated that the cerebral capillary ultrastructure is damaged in Alzheimer's disease (AD). Curiously, the regional cerebral blood flow of AD patients is also significantly lower than in age-matched control individuals. Based on these data, it has been suggested that the decreased blood supply and the cerebrovascular alterations contribute to the development of dementia. However, we have observed similar capillary damage in Parkinson's disease patients and chronically hypertensive rats in addition to AD cases, as presented here. These findings indicate that cerebral capillary damage is not exclusive for AD but occurs under other neurodegenerative disorders and hypertension, as well. We hypothesize that ultrastructural abnormalities of cerebral capillaries are causally related to decreased cerebral blood flow and create a condition that favors neurodegenerative mechanisms including the development of dementia.


Asunto(s)
Enfermedad de Alzheimer/patología , Capilares/ultraestructura , Corteza Cerebral/irrigación sanguínea , Corteza Cerebral/patología , Hipertensión/patología , Enfermedad de Parkinson/patología , Enfermedad de Alzheimer/fisiopatología , Animales , Presión Sanguínea , Capilares/patología , Humanos , Hipertensión/fisiopatología , Enfermedades Neurodegenerativas/patología , Enfermedades Neurodegenerativas/fisiopatología , Enfermedad de Parkinson/fisiopatología , Ratas , Ratas Endogámicas SHR
13.
Science ; 174(4009): 545, 1971 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-17831288
14.
Brain Res ; 206(1): 1-8, 1981 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-7470879

RESUMEN

Synaptogenesis in the molecular layer of the vermis cortex in Wistar rats between 1 and 25 days after birth was investigated. After staining with OSO4, the following parameters were measured: the density of synaptic profiles; the percentage of the neuropil area occupied by synapses; the mean diameter of the boutons; and the numerical density of synapses in a defined volume. The detailed topographical analysis enabled us to show the following: the first synapses appear diffusely in the molecular layer; after the 10th day a synaptic gradient is present between the depth and the surface area (this gradient can be found by the count of the synapses and by studying the spatial distribution of the synaptic area); this gradient is no longer seen at the 25th day, when the density of synapses is relatively uniform throughout the whole molecular layer.


Asunto(s)
Corteza Cerebelosa/crecimiento & desarrollo , Sinapsis/fisiología , Envejecimiento , Animales , Corteza Cerebelosa/ultraestructura , Microscopía Electrónica , Células de Purkinje/fisiología , Células de Purkinje/ultraestructura , Ratas , Sinapsis/ultraestructura
15.
Brain Res ; 764(1-2): 257-61, 1997 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-9295220

RESUMEN

The periaqueductal gray matter (PAG) has been implicated in a variety of different functions, including autonomic regulation. Chemical stimulation of the lateral PAG produces hypertension and tachycardia while activation of the ventrolateral PAG produces the opposite effect. While these effects are the result of alterations in sympathetic activity, little is known about whether the PAG can modulate vagal functions as well. The anterograde axonal tracing method using the plant lectin Phaseolus vulgaris leucoagglutinin (PHA-L) was used to determine whether both of the lateral and ventrolateral PAG columns project to vagal preganglionic neurons and/or to the nucleus tractus solitarius (NTS). Highly restricted PHA-L injections were made in all four PAG columns throughout their rostrocaudal extent in rats. Labeled fibers were visualized by immunohistochemistry and studied in relationship with choline acetyltransferase (ChAT) immunostained parasympathetic preganglionic neurons of the dorsal motor vagal nucleus (DMV) and nucleus ambiguous (NA). The lateral PAG projects to the lateral DMV and to the caudal part of the external NA. The ventrolateral PAG innervates the same regions and also projects to the rostral part of the external NA -- a site that contains cardiac parasympathetic preganglionic neurons. Both the lateral and ventrolateral PAG project to the NTS in a similar fashion innervating the medial, ventrolateral and commissural subnuclei. In summary, the lateral and ventrolateral PAG have similar patterns of innervation of the NTS and DMV, but their projection to the NA is different: the rostral external NA receives innervation only from the ventrolateral PAG and the lateral PAG innervates the caudal part.


Asunto(s)
Fibras Autónomas Preganglionares/fisiología , Sistema Nervioso Parasimpático/fisiología , Sustancia Gris Periacueductal/fisiología , Núcleo Solitario/fisiología , Nervio Vago/fisiología , Animales , Fibras Autónomas Preganglionares/citología , Fibras Autónomas Preganglionares/enzimología , Colina O-Acetiltransferasa/metabolismo , Histocitoquímica , Vías Nerviosas/citología , Vías Nerviosas/enzimología , Vías Nerviosas/fisiología , Sistema Nervioso Parasimpático/citología , Sistema Nervioso Parasimpático/enzimología , Sustancia Gris Periacueductal/enzimología , Fitohemaglutininas , Ratas , Ratas Sprague-Dawley , Núcleo Solitario/citología , Núcleo Solitario/enzimología , Nervio Vago/citología , Nervio Vago/enzimología
16.
Brain Res ; 792(2): 179-92, 1998 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-9593884

RESUMEN

The periaqueductal gray matter (PAG) serves as the midbrain link between forebrain emotional processing systems and motor pathways used in the defense reaction. Part of this response depends upon PAG efferent pathways that modulate cardiovascular-related sympathetic outflow systems, including those that regulate the heart. While it is known that the PAG projects to vagal preganglionic neurons, including possibly cardiovagal motoneurons, no information exists on the PAG circuits that may affect sympathetically mediated cardiac functions and, thus, the purpose of this study was to use neuroanatomical methods to identify these pathways. First, viral transneuronal retrograde tracing experiments were performed in which pseudorabies virus (PRV) was injected into the stellate ganglion of rats. After 4 days survival, five PAG regions contained transynaptically infected neurons; these included the dorsomedial, lateral and ventrolateral PAG columns as well as the Edinger-Westphal and precommissural nuclei. Second, the descending efferent PAG projections were studied with the anterograde axonal marker Phaseolus vulgaris leuco-agglutinin (PHA-L) with a particular focus on determining whether the PAG projects to the intermediolateral cell column (IML). Almost no axonal labeling was found throughout the thoracic IML suggesting that the PAG modulates sympathetic functions by indirect pathways involving synaptic relays through sympathetic premotor cell groups, especially those found in the medulla oblongata. This possibility was examined by a double tracing study. PHA-L was first injected into either the lateral or ventrolateral PAG and after 6 days, PRV was injected into the ipsilateral stellate ganglion. After an additional 4 days survival, a double immunohistochemical procedure for co-visualization of PRV and PHA-L was used to identify the sympathetic premotor regions that receive an input from the PAG. The PAG innervated specific groups of sympathetic premotor neurons in the hypothalamus, pons, and medulla as well as providing reciprocal intercolumnar connections within the PAG itself (Jansen et al., Brain Res. 784 (1998) 329-336). The major route terminates in the ventral medulla, especially within the medial region which contains sympathetic premotor neurons lying within the raphe magnus and gigantocellular reticular nucleus, pars alpha. Both serotonergic and non-serotonergic sympathetic premotor neurons in these two regions receive inputs from the PAG. Weak PAG projections to sympathetic premotor neurons were found in the rostral ventrolateral medulla (including to C1 adrenergic neurons), locus coeruleus, A5 cell group, paraventricular and lateral hypothalamic nuclei. In summary, both the lateral and ventrolateral PAG columns appear to be capable of modulating cardiac sympathetic functions via a series of indirect pathways involving sympathetic premotor neurons found in selected sites in the hypothalamus, midbrain, pons, and medulla oblongata, with the major outflow terminating in bulbospinal regions of the rostral ventromedial medulla.


Asunto(s)
Ganglios Simpáticos/citología , Corazón/inervación , Neuronas Motoras/fisiología , Sustancia Gris Periacueductal/citología , Animales , Emociones/fisiología , Femenino , Herpesvirus Suido 1 , Área Hipotalámica Lateral/citología , Masculino , Vías Nerviosas , Núcleo Hipotalámico Paraventricular/citología , Fitohemaglutininas , Núcleos del Rafe/citología , Ratas , Ratas Sprague-Dawley
17.
Brain Res ; 784(1-2): 329-36, 1998 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-9518675

RESUMEN

Chemical stimulation of the lateral or ventrolateral columns of the midbrain periaqueductal gray matter (PAG) in conscious animals produces opposite responses (viz., defensive behavior and pressor responses from the lateral column vs. quiescence and depressor responses from the ventrolateral column), raising the possibility that the two columns are interconnected. To test this hypothesis, two types of anatomical experiments were performed in rats. First, the anterograde axonal marker Phaseolus vulgaris leuco-agglutinin (PHA-L) was injected into individual PAG columns or adjoining regions which included the Edinger-Westphal, dorsal raphe, and precommissural nuclei. The results shows that each column projects bilaterally to all of the other PAG columns, and also provides local connections within its own column. Furthermore, the Edinger-Westphal and precommissural nuclei project to all four PAG columns, while the dorsal raphe nucleus projects only to the ventrolateral and lateral columns. In a second experiment, we found that cardiovascular-related PAG projection neurons of both the lateral and ventrolateral columns receive an input from the reciprocal PAG column. This was demonstrated by a double tracer neuroanatomical study in which PHA-L was first iontophoretically ejected into either the lateral or ventrolateral PAG columns and then, several days later the retrograde transneuronal viral tracer, pseudorabies virus, was injected into the stellate sympathetic ganglion. Intra-PAG circuits were visualized by a dual immunohistochemical procedure. These results suggest that during the fight-or-flight response when the 'fight' program is activated, inhibition of the 'flight' PAG network may occur and the converse situation may occur during the flight response.


Asunto(s)
Mapeo Encefálico , Vías Nerviosas/anatomía & histología , Sustancia Gris Periacueductal/anatomía & histología , Animales , Ganglios Basales/anatomía & histología , Ganglios Basales/fisiología , Sistema Cardiovascular/inervación , Inmunohistoquímica , Iontoforesis , Vías Nerviosas/fisiología , Sustancia Gris Periacueductal/fisiología , Fitohemaglutininas , Núcleos del Rafe/anatomía & histología , Núcleos del Rafe/fisiología , Ratas , Ratas Sprague-Dawley
18.
Neurosci Lett ; 3(5-6): 265-74, 1976 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19604897

RESUMEN

Surface evoked and single unit responses to vibrissa stimulation were investigated in the PosteroMedial Barrel SubField (PMBSF) area of rat and mouse SI cortex. The data strongly suggest a correspondence between the focal point of the surface projection region and the underlying barrel hollow. Units activated by the whisker movement were recorded in all cortical layers. They responded mainly in a phasic manner. Units sensitive to direction of stimulation as well as units receiving functional convergence from more than one vibrissa are described.

19.
Neurosci Lett ; 11(3): 301-6, 1979 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-514543

RESUMEN

In normal adult rats, the mystacial vibrissae and the common fur of the snout project at different loci on the SI cortex. The surface area of the normal fur projection is 0.8 mm2, whereas the vibrissa field amounts to 3-4 mm2. In rats dewhiskered since birth, the vibrissa area can still be identified through the projections from ipsilateral vibrissae (undamaged side). It is shown that in the absence of the vibrissae since birth, the vibrissa area, and this alone, is invaded by projections from the contralateral fur (damaged side).


Asunto(s)
Cara/inervación , Cabello , Órganos de los Sentidos/inervación , Corteza Somatosensorial/crecimiento & desarrollo , Animales , Electrofisiología , Cabello/fisiología , Ratas , Corteza Somatosensorial/fisiología
20.
Int J Biol Markers ; 16(4): 227-32, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11820716

RESUMEN

In this study the nodal staging sensitivity of sentinel lymph node biopsy (SLNB) with detailed pathological and molecular biological examination has been investigated and compared to that of axillary lymph node dissection (ALND) with routine histological evaluation. Sentinel lymph nodes (SLNs) were removed by the dual-agent injection technique in 68 patients with primary, clinically node-negative breast cancer. Forty-seven patients had negative SLNs according to hematoxylin and eosin (H&E) staining. These H&E-negative SLNs were serially sectioned and examined at 250 microm levels by anticytokeratin immunohistochemistry (IHC). In 14 patients the SLNs were also investigated by cytokeratin 20 (CK20) reverse transcriptase polymerase chain reaction (RT-PCR). SLNB with IHC increased the node-positive rate by 26% (by 40% in tumors less than or equal to 2 cm in size (pT1) and by 9% in tumors more than 2 cm but less than or equal to 5 cm in size (pT2)). The sensitivity of SLNB with IHC was superior to that of ALND with routine histology in pT1 tumors and identical in pT2 tumors. The concordance between histology and RT-PCR was only 21%, and in two of three cases with positive histological results RT-PCR was negative. In conclusion, SLNB with detailed pathological and/or molecular biological evaluation can improve the sensitivity of regional staging. ALND can probably be abandoned in patients with pT1 SLN-negative breast cancer. Further prospective studies are required to determine the clinical significance of these detailed SLN evaluation techniques, but at present these methods are still investigational.


Asunto(s)
Neoplasias de la Mama/patología , Proteínas de Filamentos Intermediarios/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Biopsia del Ganglio Linfático Centinela , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmunohistoquímica , Proteínas de Filamentos Intermediarios/análisis , Queratina-20 , Metástasis Linfática , Persona de Mediana Edad , Estadificación de Neoplasias
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