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1.
Agric Syst ; 191: 103152, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36570633

RESUMEN

Context: Resilience is the ability to deal with shocks and stresses, including the unknown and previously unimaginable, such as the Covid-19 crisis. Objective: This paper assesses (i) how different farming systems were exposed to the crisis, (ii) which resilience capacities were revealed and (iii) how resilience was enabled or constrained by the farming systems' social and institutional environment. Methods: The 11 farming systems included have been analysed since 2017. This allows a comparison of pre-Covid-19 findings and the Covid-19 crisis. Pre-Covid findings are from the SURE-Farm systematic sustainability and resilience assessment. For Covid-19 a special data collection was carried out during the early stage of lockdowns. Results and conclusions: Our case studies found limited impact of Covid-19 on the production and delivery of food and other agricultural products. This was due to either little exposure or the agile activation of robustness capacities of the farming systems in combination with an enabling institutional environment. Revealed capacities were mainly based on already existing connectedness among farmers and more broadly in value chains. Across cases, the experience of the crisis triggered reflexivity about the operation of the farming systems. Recurring topics were the need for shorter chains, more fairness towards farmers, and less dependence on migrant workers. However, actors in the farming systems and the enabling environment generally focused on the immediate issues and gave little real consideration to long-term implications and challenges. Hence, adaptive or transformative capacities were much less on display than coping capacities. The comparison with pre-Covid findings mostly showed similarities. If challenges, such as shortage of labour, already loomed before, they persisted during the crisis. Furthermore, the eminent role of resilience attributes was confirmed. In cases with high connectedness and diversity we found that these system characteristics contributed significantly to dealing with the crisis. Also the focus on coping capacities was already visible before the crisis. We are not sure yet whether the focus on short-term robustness just reflects the higher visibility and urgency of shocks compared to slow processes that undermine or threaten important system functions, or whether they betray an imbalance in resilience capacities at the expense of adaptability and transformability. Significance: Our analysis indicates that if transformations are required, e.g. to respond to concerns about transnational value chains and future pandemics from zoonosis, the transformative capacity of many farming systems needs to be actively enhanced through an enabling environment.

2.
J Cardiobiol ; 5(1)2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-30931350

RESUMEN

AIM: The purpose of the study was to localize matrix metalloproteinase (MMP)-14, -9, and -2 in the A7r5 smooth muscle cell and to understand the interaction between these MMPs and the cytoskeleton. This interaction was observed under non-stimulating and phorbol 12, 13-dibutyrate (PDBu)-stimulating conditions. METHODS: Confocal microscopy was utilized to define the localizations of MMPs and tissue inhibitor of matrix metalloproteinases (TIMPs) in the A7r5 cell and to determine interaction between MMPs and the cytoskeleton. Under PDBu-stimulating conditions, the presence of MMP active forms and activity by gel zymography was evaluated in the A7r5 cell. Actin and microtubule-polymerization inhibitors were used to evaluate MMP interaction with the cytoskeleton and the cytoskeleton was observed on matrix and within a Type I collagen gel. RESULTS: MMP-14, -9, and -2 were localized to the podosome in the A7r5 smooth muscle cell and interactions were seen with these MMPs and the actin cytoskeleton. PDBu-stimulation induced increases in the protein abundance of the active forms of the MMPs and MMP-2 activity was increased. MMPs also interact with a-actin and not ß-tubulin in the A7r5 cell. Galardin, also known as GM-6001, was shown to inhibit podosome formation and prevented MMP localization to the podosome. This broad spectrum MMP inhibitor also prevented collagen gel contraction and prevented cell adhesion and spreading of A7r5 cells within this collagen matrix. CONCLUSION: MMPs are important in the formation and function of podosomes in the A7r5 smooth muscle cell. MMPs interact with a-actin and not ß-tubulin in the A7r5 cell. Podosomes play an important role in cell migration and understanding the function of podosomes can lead to insights into cancer metastasis and cardiovascular disease.

3.
Scand J Med Sci Sports ; 17(2): 128-32, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17394473

RESUMEN

The effects of hormonal status and activity levels on Achilles tendon structure were examined in asymptomatic post-menopausal women. It was hypothesized that women using hormone replacement therapy (HRT) would have better tendon structure than those not using HRT and that active women would have poorer tendon structure than inactive women. Eighty-five women including 53 active women (regular golf players) and 32 controls (healthy but inactive women) recorded their HRT and menopausal history and underwent basic anthropometric measurements. Women were divided into two groups based on their hormonal status: those currently using HRT; and those who had never used HRT or ceased using HRT at least 12 months prior to the study. Achilles tendons were examined with ultrasound and categorized as normal or abnormal, and the diameter of each tendon (mm) was recorded. Active women had a greater prevalence of tendon abnormality (P=0.10) and thicker Achilles tendons than inactive women (P<0.05). Active women on HRT had less tendon abnormality (P=0.056) than active women not on HRT and significantly less tendon thickness (P<0.05). This study indicates that Achilles tendon diameter is greater in active post-menopausal women. Hormone replacement therapy appeared to ameliorate this effect in active women. A similar effect from HRT on the Achilles tendons of inactive women was not apparent.


Asunto(s)
Tendón Calcáneo/anatomía & histología , Terapia de Reemplazo de Estrógeno , Tendón Calcáneo/efectos de los fármacos , Estudios de Casos y Controles , Femenino , Golf , Humanos , Persona de Mediana Edad , Posmenopausia , Caminata
4.
Respir Med ; 101(3): 616-27, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16908126

RESUMEN

OBJECTIVE: Armodafinil is the R-enantiomer of racemic modafinil and has a significantly longer half-life than the S-enantiomer. This study evaluated armodafinil 150 mg/day as an adjunct treatment for residual excessive sleepiness in patients with obstructive sleep apnea/hypopnea syndrome (OSA/HS) who were otherwise well controlled with nasal continuous positive airway pressure (nCPAP). We assessed the ability of armodafinil to improve wakefulness and cognition and reduce fatigue in this population. METHODS: In this 12-week, randomized, double-blind study, patients (n=259) received armodafinil (150 mg) or placebo once daily. Efficacy assessments at baseline and weeks 4, 8, and 12 included the Maintenance of Wakefulness Test (MWT), Clinical Global Impression of Change (CGI-C), Cognitive Drug Research battery, Epworth Sleepiness Scale, and Brief Fatigue Inventory. RESULTS: At final visit, mean (SD) MWT sleep latency increased from baseline by 2.3 (7.8) min with armodafinil and decreased by 1.3 (7.1) min in the placebo group (P=0.0003). Armodafinil improved clinical condition (CGI-C, 71% vs. 53% for armodafinil and placebo, respectively; P=0.0069). Armodafinil significantly improved episodic secondary memory (P=0.0102) and patient-estimated wakefulness (P<0.01) and reduced fatigue (P<0.05) compared with placebo. Armodafinil did not adversely affect nCPAP use. The most common adverse event associated with armodafinil was headache. Sleep macroarchitecture was not altered by armodafinil. CONCLUSION: Adjunct treatment with armodafinil significantly improved alertness, overall clinical condition, and long-term memory. Armodafinil also reduced fatigue and the impact of sleepiness on daily activities in patients with OSA/HS who have residual excessive sleepiness notwithstanding regular use of nCPAP. Armodafinil was well tolerated.


Asunto(s)
Compuestos de Bencidrilo/uso terapéutico , Estimulantes del Sistema Nervioso Central/uso terapéutico , Memoria/efectos de los fármacos , Apnea Obstructiva del Sueño/tratamiento farmacológico , Vigilia/efectos de los fármacos , Adyuvantes Farmacéuticos/uso terapéutico , Adulto , Anciano , Atención/efectos de los fármacos , Atención/fisiología , Compuestos de Bencidrilo/efectos adversos , Estimulantes del Sistema Nervioso Central/efectos adversos , Presión de las Vías Aéreas Positiva Contínua , Método Doble Ciego , Fatiga/prevención & control , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modafinilo , Pruebas Psicológicas , Sueño/efectos de los fármacos , Sueño/fisiología , Apnea Obstructiva del Sueño/fisiopatología , Factores de Tiempo , Resultado del Tratamiento
5.
Am J Respir Crit Care Med ; 164(9): 1675-81, 2001 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11719309

RESUMEN

Patients with obstructive sleep apnea/hypopnea syndrome can experience residual daytime sleepiness despite regular use of nasal continuous positive airway pressure therapy. This randomized, double-blind, placebo-controlled, parallel group study assessed the efficacy and safety of modafinil for the treatment of residual daytime sleepiness in such patients. Patients received modafinil (n = 77) (200 mg/d, Week 1; 400 mg/d, Weeks 2 to 4) or matching placebo (n = 80) once daily for 4 wk. Modafinil significantly improved daytime sleepiness, with significantly greater mean changes from baseline in Epworth Sleepiness Scale scores at Weeks 1 and 4 (p < 0.001) and in multiple sleep latency times (MSLT) at Week 4 (p < 0.05). The percentage of patients with normalized daytime sleepiness (Epworth score < 10) was significantly higher with modafinil (51%) than with placebo (27%) (p < 0.01), but not for MSLT (> 10 min; 29% versus 25%). Headache (modafinil, 23%; placebo, 11%; p = 0.044) and nervousness (modafinil, 12%; placebo, 3%; p = 0.024) were the most common adverse events. During modafinil or placebo treatment, the mean duration of nCPAP use was 6.2 h/night, with no significant change from baseline observed between groups. Modafinil may be a useful adjunct treatment for the management of residual daytime sleepiness in patients with obstructive sleep apnea/hypopnea syndrome who are regular users of nasal continuous positive airway pressure therapy.


Asunto(s)
Compuestos de Bencidrilo/uso terapéutico , Estimulantes del Sistema Nervioso Central/uso terapéutico , Apnea Obstructiva del Sueño/tratamiento farmacológico , Fases del Sueño/efectos de los fármacos , Adulto , Anciano , Análisis de Varianza , Compuestos de Bencidrilo/efectos adversos , Estimulantes del Sistema Nervioso Central/efectos adversos , Terapia Combinada , Seguridad de Productos para el Consumidor , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modafinilo , Polisomnografía , Respiración con Presión Positiva , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas
6.
Soc Work ; 46(4): 325-38, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11682974

RESUMEN

The case-based research discussed in this article describes the variety of strategies mothers and young children spontaneously used to negotiate the complexities of foster care visiting. Nine mothers and their 24- to 48-month-old children were videotaped during their foster care visits. After each visit, the mother participated in an in-depth, audiotaped interview. Mothers and children displayed a wide variety of responses to visits. Mothers spontaneously discussed the challenges of visits, particularly separating at the end of visits. Implications for enhancing the quality of visits and strengthening services are discussed.


Asunto(s)
Protección a la Infancia , Cuidados en el Hogar de Adopción/psicología , Relaciones Madre-Hijo , Adolescente , Adulto , Preescolar , Femenino , Humanos , Masculino , Madres/psicología , Estados Unidos , Grabación de Cinta de Video
7.
Am J Respir Crit Care Med ; 162(2 Pt 1): 406-11, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10934061

RESUMEN

Upper airway resistance syndrome (UARS) is defined by excessive daytime sleepiness and tiredness, and is associated with increased breathing effort. Its polygraphic features involve progressive increases in esophageal pressure (Pes), terminated by arousal (AR) as defined by the American Sleep Disorders Association (ASDA). With the arousal there is an abrupt decrease in Pes, called Pes reversal. However, Pes reversal can be seen without the presence of an AR. We performed spectral analysis on electroencephalographic data from a central lead for both AR and nonarousal (N-AR) events obtained from 15 UARS patients (eight men and seven women). Delta band activity was increased before and surrounding Pes reversal regardless of the presence or absence of AR. In the period after Pes reversal, alpha, sigma, and beta activity showed a greater increase in AR events than in N-AR events. The Pes measures were identical leading up to the point of reversal, but showed a longer-lasting and significantly greater decrease in respiratory effort after an AR. The data indicate that substantial electroencephalographic changes can be identified in association with Pes events, even when ARs cannot be detected according to standard criteria; however, visually identifiable electroencephalographic arousals clearly have a greater impact on ongoing inspiratory effort.


Asunto(s)
Resistencia de las Vías Respiratorias/fisiología , Electroencefalografía , Mecánica Respiratoria/fisiología , Síndromes de la Apnea del Sueño/fisiopatología , Adulto , Nivel de Alerta/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad
10.
Prev Med ; 27(2): 168-71, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9578989

RESUMEN

Although the potential vulnerability of children's brain development is generally recognized, relatively little is known about the timing, resiliency, or mechanisms involved. While animal research should be applied only cautiously to human policy, some findings do have important clinical implications. This paper briefly reviews animal studies demonstrating the effects of experience on brain structure. Contemporary theories emphasize the self-organizing potential of brain structure, particularly regions that seem to have evolved for the purpose of storing information. We emphasize three major findings: (1) many regions of the brain are responsive to experience, but they differ in the types of information stored and in their developmental timing. (2) One type of plasticity is typically embedded in a developmental program, and it requires appropriate timing and quality of the information stored for the animal's development to be normal. (3) Another category of plasticity stores information that is idiosyncratic and unpredictable, but is often useful for species such as humans that learn throughout their life span. We therefore expect that some aspects of human brain development use the first type of plasticity and that abnormal experience or deprivation may cause lasting harm to brain and behavior. However, because the other type of plasticity lasts a lifetime, efforts such as psychotherapy or social interventions may help heal a wounded brain.


Asunto(s)
Encéfalo/crecimiento & desarrollo , Desarrollo Infantil/fisiología , Plasticidad Neuronal/fisiología , Animales , Niño , Preescolar , Período Crítico Psicológico , Humanos , Lactante , Recién Nacido , Carencia Psicosocial , Sinapsis/fisiología
11.
Psychopharmacology (Berl) ; 119(2): 179-85, 1995 May.
Artículo en Inglés | MEDLINE | ID: mdl-7659765

RESUMEN

The objective of this study was to investigate the role of serotonin (5-HT) in mediating the effects of cocaine in humans. To accomplish this, 12 subjects each participated in two randomized, double-blind test sessions separated by 1 week. In one session, subjects underwent acute depletion of the 5-HT amino acid precursor tryptophan (TRP), followed by a test dose of intranasal cocaine. In the other session, the cocaine test dose was preceded by sham depletion. Subject ratings of cocaine "high" were significantly lower following active TRP depletion than after the sham procedure. Subjects also showed an earlier but less sustained rise in self-rated nervousness during active TRP depletion. These findings are consistent with the hypothesis that 5-HT may be involved in mediating the euphorigenic and modulating the anxiogenic effects of cocaine in humans, either directly or through actions on other (e.g., dopaminergic) systems.


Asunto(s)
Afecto/efectos de los fármacos , Cocaína/farmacología , Serotonina/fisiología , Triptófano/sangre , Adulto , Afecto/fisiología , Depresión Química , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos Relacionados con Sustancias/fisiopatología , Trastornos Relacionados con Sustancias/psicología , Factores de Tiempo , Triptófano/metabolismo
12.
Arch Gen Psychiatry ; 51(9): 713-9, 1994 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8080348

RESUMEN

BACKGROUND: The primary objective of the study was to prospectively determine possible noradrenergic dysregulation in cocaine addicts by assessing biochemical, behavioral, and cardiovascular responses to intravenous yohimbine hydrochloride during early and late discontinuation of cocaine use. METHODS: Twelve male and two female hospitalized cocaine-dependent subjects (mean +/- SD age, 30.9 +/- 7.3 years) who were not seeking primary treatment for addiction participated voluntarily for monetary remuneration. Following an initial test dose of intranasal cocaine, 2 mg/kg, cocaine addicts received single-blind, monitored cocaine insufflation, 2 mg/kg three times each day, for 3 consecutive days. One to two days (early discontinuation) and 15 to 16 days (late discontinuation) after the last dose of cocaine, subjects received double-blind, randomized intravenous infusions of yohimbine hydrochloride, 0.4 mg/kg, or placebo. Plasma 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and plasma cortisol levels, anxiety-related symptoms on clinician- and subject-rated scales, blood pressure, and heart rate were measured throughout each test day. Ten of 14 subjects completed the entire study. RESULTS: Subjects had a significantly greater placebo-corrected MHPG response to yohimbine during early compared with late discontinuation. Subjects rated themselves significantly more nervous following yohimbine administration during early compared with late discontinuation. Seventy-one percent of subjects experienced a yohimbine-induced panic attack during early discontinuation compared with none during late discontinuation. CONCLUSIONS: The results of this study provide evidence of an underlying dysregulation in noradrenergic function and a vulnerability to panic anxiety during early discontinuation of cocaine use in addicts. Additional investigations of noradrenergic function appear warranted to further clarify derangements associated with cocaine addiction.


Asunto(s)
Cocaína , Norepinefrina/fisiología , Síndrome de Abstinencia a Sustancias/fisiopatología , Trastornos Relacionados con Sustancias/rehabilitación , Administración Intranasal , Adulto , Cocaína/administración & dosificación , Cocaína/efectos adversos , Método Doble Ciego , Femenino , Hospitalización , Humanos , Hidrocortisona/sangre , Infusiones Intravenosas , Insuflación , Masculino , Metoxihidroxifenilglicol/sangre , Persona de Mediana Edad , Trastorno de Pánico/inducido químicamente , Trastorno de Pánico/epidemiología , Estudios Prospectivos , Método Simple Ciego , Síndrome de Abstinencia a Sustancias/epidemiología , Síndrome de Abstinencia a Sustancias/etiología , Yohimbina/administración & dosificación , Yohimbina/farmacología
13.
Glia ; 11(1): 73-80, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-7520887

RESUMEN

Rats reared from weaning in a complex environment have an increase in 1) glial surface area, 2) capillary volume, and 3) the number of synapses, per neuron. In that paradigm it has not been possible to determine whether the glial increase more closely correlates with the increase in synaptic numbers or with angiogenesis. More recently we have found that rats that exercised had an increase in the density of capillaries without an increase in the synaptic numbers, whereas rats that learned new motor skills had a greater number of synapses per neuron without an increase in the density of capillaries. Those findings provided the opportunity to investigate whether changes in glial volume in the cerebellum correspond to changes in the number of synapses or in capillary volume. Glial area fraction estimates were obtained using point counts on electron micrographs from the previous studies. The skill learning group had a greater volume of molecular layer per Purkinje cell, and also a greater volume of glia per Purkinje cell, than rats in either an inactive group or rats in two exercise groups. No significant differences were found in glial volume per synapse and glial volume per capillary across groups, although there was a tendency for glial volume per capillary to be lower in the exercise groups. The data indicate that glial volume correlates with synaptic numbers and not with capillary density.


Asunto(s)
Aprendizaje/fisiología , Destreza Motora/fisiología , Neovascularización Patológica/patología , Neuroglía/ultraestructura , Esfuerzo Físico/fisiología , Sinapsis/fisiología , Animales , Capilares/fisiología , Corteza Cerebelosa/citología , Corteza Cerebelosa/ultraestructura , Femenino , Neuroglía/fisiología , Plasticidad Neuronal/fisiología , Células de Purkinje/ultraestructura , Ratas
14.
Psychopharmacology (Berl) ; 111(1): 39-46, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-7870932

RESUMEN

Simultaneous abuse of cocaine and ethanol is a common occurrence. Cocaethylene, the ethyl ester of benzoylecgonine, has been detected in the urine of patients reporting concurrent use of cocaine and ethanol, and high levels have been found in the blood of victims of fatal drug overdose. This placebo-controlled, double-blind study examined the pharmacokinetic, physiologic, and behavioral effects of dual cocaine and ethanol administration in humans (n = 6). Cocaethylene was found in the plasma only after administration of both cocaine and ethanol, and appeared to be eliminated more slowly than cocaine. Plasma cocaine concentrations were significantly higher during cocaine/ethanol administration. Euphorigenic effects were both enhanced and prolonged, and heart rate was significantly increased, following cocaine/ethanol administration as compared to administration of cocaine or ethanol alone.


Asunto(s)
Conducta/efectos de los fármacos , Cocaína/análogos & derivados , Inhibidores de Captación de Dopamina/sangre , Etanol/farmacología , Adulto , Afecto/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Cocaína/sangre , Cocaína/farmacología , Método Doble Ciego , Interacciones Farmacológicas , Etanol/sangre , Euforia/efectos de los fármacos , Semivida , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino
15.
J Cereb Blood Flow Metab ; 12(1): 110-9, 1992 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1370068

RESUMEN

This study compared the morphology of cerebellar cortex in adult female rats exposed for 1 month to repetitive exercise, motor learning, or an inactive condition. In the exercise conditions, rats that were run on a treadmill or housed with access to a running wheel had a shorter diffusion distance from blood vessels in the molecular layer of the paramedian lobule when compared to rats housed individually or rats that participated in a motor skill learning task. Rats taught complex motor skills substantially increased the volume of the molecular layer per Purkinje neuron and increased blood vessel number sufficiently to maintain the diffusion distance. These results dissociate angiogenesis associated with increased neuropil volume (as seen in the motor learning group) from angiogenesis associated with increased metabolic demands (as seen in the exercise groups). While the volume fraction of mitochondria did not differ among groups, the mitochondrial volume fraction per Purkinje cell was significantly increased in the motor skill rats. This appears to parallel the previously reported increase in synapses and associated neuropil volume change.


Asunto(s)
Cerebelo/irrigación sanguínea , Aprendizaje , Destreza Motora , Neovascularización Patológica , Esfuerzo Físico , Animales , Capilares/ultraestructura , Cerebelo/ultraestructura , Femenino , Ratas
16.
Neurobiol Aging ; 12(4): 325-8; discussion 352-5, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1961360

RESUMEN

A common analogy to aging is that of a boulder being worn down to rubble by the unremitting onslaught of time. In contrast, Swaab's "use it or lose it" concept is important because it emphasizes some positive consequences of experience. For example, early exposure to complex experience may offer some protection from "wear and tear" degradation through improvements in vascular support, diet, exercise, and coping with stress. Exposure to complex experience in old age can also generate new synapses in the cerebral cortex and cerebellum. This new perspective is not completely positive, however, because it appears that the senescent breakdown of supporting systems may ultimately constrain the positive benefits of experience in old age. Thus the evidence indicates that the use of environmental therapies should encompass the entire life span to produce successful aging.


Asunto(s)
Envejecimiento/fisiología , Enfermedad de Alzheimer/fisiopatología , Encéfalo/fisiología , Anciano , Enfermedad de Alzheimer/patología , Encéfalo/patología , Encéfalo/fisiopatología , Humanos , Longevidad
17.
Exp Neurol ; 111(2): 204-9, 1991 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1989898

RESUMEN

Young adult rats (60 days old) were placed in complex environments (EC) or kept in individual cages (IC) for 10, 30, or 60 days. Previously reported findings in these same animals of synaptogenesis, decreased neuronal density, and increased cortical thickness in the EC animals demonstrated that cortical volume substantially expanded after 30 days. Such expansion would have spread apart existing capillaries and mitochondria, thereby diluting metabolic support. However, capillary spacing and mitochondrial volume fraction were maintained in these EC animals after 30 days, suggesting that new capillaries and mitochondria had infiltrated the tissue. Furthermore, many small vessels appeared after 10 days of complex experience, followed by expansion in vessel size until vessels from rats in EC for 60 days were larger than those from rats in IC for 60 days. The findings of constant vessel spacing in the face of expanding tissue volume, along with a set of small vessels that subsequently increased in size, suggest that small-sized new vessels were introduced in EC cortex by 10 days but had not matured in size until after 30 days. The results indicate that young adult rats can generate new capillaries and mitochondria in response to increased metabolic demands, but in a less vigorous fashion than in previously described weanling animals.


Asunto(s)
Capilares/fisiología , Mitocondrias/fisiología , Plasticidad Neuronal , Corteza Visual/fisiología , Animales , Volumen Sanguíneo , Neuronas/ultraestructura , Ratas , Ratas Endogámicas , Medio Social
18.
Exp Neurol ; 111(1): 74-9, 1991 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1984435

RESUMEN

Glial hypertrophy is associated with synaptogenesis in visual cortex and with stress-induced damage in the hippocampus. This study examined astrocytes in the dentate gyrus of male weanling rats exposed to complex or standard laboratory environments. No group differences in astrocytic surface density were observed, as expected in this brain region where group differences in synaptogenesis in male rats are reportedly minimal. Similarly, no group differences in adrenal weight were observed. Across all treatment groups, however, a significant positive correlation (r = 0.57) between adrenal weight and surface density of astrocytic processes was found. Considerable variation in responses of individual rats to their environments occurs in both the complex and the laboratory cage environments, and animals responding poorly may have had heavier adrenals and greater astrocyte reactivity in the dentate gyrus. Thus astrocyte hypertrophy in the dentate gyrus reflects the stress history of the individual rat and not any differential effects of rearing in a complex or a laboratory cage environment.


Asunto(s)
Astrocitos/patología , Ambiente , Hipocampo/patología , Estrés Psicológico/patología , Glándulas Suprarrenales/anatomía & histología , Animales , Hipertrofia , Masculino , Tamaño de los Órganos , Ratas , Sinapsis/patología
19.
Proc Natl Acad Sci U S A ; 87(14): 5568-72, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1695380

RESUMEN

The role of the cerebellar cortex in motor learning was investigated by comparing the paramedian lobule of adult rats given difficult acrobatic training to that of rats that had been given extensive physical exercise or had been inactive. The paramedian lobule is activated during limb movements used in both acrobatic training and physical exercise. Acrobatic animals had greater numbers of synapses per Purkinje cell than animals from the exercise or inactive groups. No significant difference in synapse number or size between the exercised and inactive groups was found. This indicates that motor learning required of the acrobatic animals, and not repetitive use of synapses during physical exercise, generates new synapses in cerebellar cortex. In contrast, exercise animals had a greater density of blood vessels in the molecular layer than did either the acrobatic or inactive animals, suggesting that increased synaptic activity elicited compensatory angiogenesis.


Asunto(s)
Corteza Cerebelosa/fisiología , Aprendizaje , Actividad Motora , Sinapsis/fisiología , Animales , Vasos Sanguíneos/citología , Vasos Sanguíneos/fisiología , Corteza Cerebelosa/irrigación sanguínea , Femenino , Neovascularización Patológica , Esfuerzo Físico , Células de Purkinje/citología , Células de Purkinje/fisiología , Ratas , Factores de Tiempo
20.
Dev Psychobiol ; 22(7): 727-52, 1989 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2680685

RESUMEN

Rats kept in complex environments (EC) show an array of brain changes relative to animals housed individually (IC). These effects have been explained as due to (a) information storage, (b) chronic stress that causes brain damage, or (c) neuroendocrine effects on brain maturation. Complex experience also affects somatic growth and organ development, and these may be related to the EC/IC brain differences. We have compared somatic growth and internal organs of 315 weanling and adult rats with various histories. (a) Young EC rats showed slower skeletal and visceral growth, while many brain components expand. (b) Although thymus and spleen were lighter in young ECs, immunocompetence was nonsignificantly (p less than .07) higher than in ICs. (c) Somatic growth of adult rats was slow and not very responsive to experience, whereas studies have shown EC/IC brain effects similar to those in young rats. (d) Males had slightly greater EC/IC somatic and visceral differences. (e) The stress index, adrenal weight, varied across age and experience, so chronic stress can not explain EC/IC brain differences. Training paradigms show brain changes similar to those from complex experience, occurring specifically with learning and in brain regions using the information. Learning and memory, therefore remain the best explanation of the EC brain effects.


Asunto(s)
Peso Corporal/fisiología , Encéfalo/crecimiento & desarrollo , Aprendizaje/fisiología , Memoria/fisiología , Estrés Fisiológico/complicaciones , Glándulas Suprarrenales/crecimiento & desarrollo , Animales , Animales Recién Nacidos/crecimiento & desarrollo , Desarrollo Óseo , Huesos/anatomía & histología , Femenino , Riñón/crecimiento & desarrollo , Hígado/crecimiento & desarrollo , Masculino , Tamaño de los Órganos , Distribución Aleatoria , Ratas , Ratas Endogámicas , Caracteres Sexuales , Bazo/crecimiento & desarrollo , Timo/crecimiento & desarrollo , Factores de Tiempo
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