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1.
Agric Syst ; 191: 103152, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36570633

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-30931350

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-17394473

RESUMO

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.


Assuntos
Tendão do Calcâneo/anatomia & histologia , Terapia de Reposição de Estrogênios , Tendão do Calcâneo/efeitos dos fármacos , Estudos de Casos e Controles , Feminino , Golfe , Humanos , Pessoa de Meia-Idade , Pós-Menopausa , Caminhada
4.
Respir Med ; 101(3): 616-27, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16908126

RESUMO

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.


Assuntos
Compostos Benzidrílicos/uso terapêutico , Estimulantes do Sistema Nervoso Central/uso terapêutico , Memória/efeitos dos fármacos , Apneia Obstrutiva do Sono/tratamento farmacológico , Vigília/efeitos dos fármacos , Adjuvantes Farmacêuticos/uso terapêutico , Adulto , Idoso , Atenção/efeitos dos fármacos , Atenção/fisiologia , Compostos Benzidrílicos/efeitos adversos , Estimulantes do Sistema Nervoso Central/efeitos adversos , Pressão Positiva Contínua nas Vias Aéreas , Método Duplo-Cego , Fadiga/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modafinila , Testes Psicológicos , Sono/efeitos dos fármacos , Sono/fisiologia , Apneia Obstrutiva do Sono/fisiopatologia , Fatores de Tempo , Resultado do Tratamento
5.
Am J Respir Crit Care Med ; 164(9): 1675-81, 2001 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-11719309

RESUMO

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.


Assuntos
Compostos Benzidrílicos/uso terapêutico , Estimulantes do Sistema Nervoso Central/uso terapêutico , Apneia Obstrutiva do Sono/tratamento farmacológico , Fases do Sono/efeitos dos fármacos , Adulto , Idoso , Análise de Variância , Compostos Benzidrílicos/efeitos adversos , Estimulantes do Sistema Nervoso Central/efeitos adversos , Terapia Combinada , Qualidade de Produtos para o Consumidor , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modafinila , Polissonografia , Respiração com Pressão Positiva , Índice de Gravidade de Doença , Estatísticas não Paramétricas
6.
Soc Work ; 46(4): 325-38, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11682974

RESUMO

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.


Assuntos
Proteção da Criança , Cuidados no Lar de Adoção/psicologia , Relações Mãe-Filho , Adolescente , Adulto , Pré-Escolar , Feminino , Humanos , Masculino , Mães/psicologia , Estados Unidos , Gravação de Videoteipe
7.
Am J Respir Crit Care Med ; 162(2 Pt 1): 406-11, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10934061

RESUMO

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.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Eletroencefalografia , Mecânica Respiratória/fisiologia , Síndromes da Apneia do Sono/fisiopatologia , Adulto , Nível de Alerta/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
10.
Prev Med ; 27(2): 168-71, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9578989

RESUMO

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.


Assuntos
Encéfalo/crescimento & desenvolvimento , Desenvolvimento Infantil/fisiologia , Plasticidade Neuronal/fisiologia , Animais , Criança , Pré-Escolar , Período Crítico Psicológico , Humanos , Lactente , Recém-Nascido , Carência Psicossocial , Sinapses/fisiologia
11.
Psychopharmacology (Berl) ; 119(2): 179-85, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7659765

RESUMO

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.


Assuntos
Afeto/efeitos dos fármacos , Cocaína/farmacologia , Serotonina/fisiologia , Triptofano/sangue , Adulto , Afeto/fisiologia , Depressão Química , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de Substâncias/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Fatores de Tempo , Triptofano/metabolismo
12.
Arch Gen Psychiatry ; 51(9): 713-9, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8080348

RESUMO

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.


Assuntos
Cocaína , Norepinefrina/fisiologia , Síndrome de Abstinência a Substâncias/fisiopatologia , Transtornos Relacionados ao Uso de Substâncias/reabilitação , Administração Intranasal , Adulto , Cocaína/administração & dosagem , Cocaína/efeitos adversos , Método Duplo-Cego , Feminino , Hospitalização , Humanos , Hidrocortisona/sangue , Infusões Intravenosas , Insuflação , Masculino , Metoxi-Hidroxifenilglicol/sangue , Pessoa de Meia-Idade , Transtorno de Pânico/induzido quimicamente , Transtorno de Pânico/epidemiologia , Estudos Prospectivos , Método Simples-Cego , Síndrome de Abstinência a Substâncias/epidemiologia , Síndrome de Abstinência a Substâncias/etiologia , Ioimbina/administração & dosagem , Ioimbina/farmacologia
13.
Glia ; 11(1): 73-80, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-7520887

RESUMO

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.


Assuntos
Aprendizagem/fisiologia , Destreza Motora/fisiologia , Neovascularização Patológica/patologia , Neuroglia/ultraestrutura , Esforço Físico/fisiologia , Sinapses/fisiologia , Animais , Capilares/fisiologia , Córtex Cerebelar/citologia , Córtex Cerebelar/ultraestrutura , Feminino , Neuroglia/fisiologia , Plasticidade Neuronal/fisiologia , Células de Purkinje/ultraestrutura , Ratos
14.
Psychopharmacology (Berl) ; 111(1): 39-46, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-7870932

RESUMO

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.


Assuntos
Comportamento/efeitos dos fármacos , Cocaína/análogos & derivados , Inibidores da Captação de Dopamina/sangue , Etanol/farmacologia , Adulto , Afeto/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Cocaína/sangue , Cocaína/farmacologia , Método Duplo-Cego , Interações Medicamentosas , Etanol/sangue , Euforia/efeitos dos fármacos , Meia-Vida , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino
15.
J Cereb Blood Flow Metab ; 12(1): 110-9, 1992 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1370068

RESUMO

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.


Assuntos
Cerebelo/irrigação sanguínea , Aprendizagem , Destreza Motora , Neovascularização Patológica , Esforço Físico , Animais , Capilares/ultraestrutura , Cerebelo/ultraestrutura , Feminino , Ratos
16.
Neurobiol Aging ; 12(4): 325-8; discussion 352-5, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1961360

RESUMO

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.


Assuntos
Envelhecimento/fisiologia , Doença de Alzheimer/fisiopatologia , Encéfalo/fisiologia , Idoso , Doença de Alzheimer/patologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Humanos , Longevidade
17.
Exp Neurol ; 111(2): 204-9, 1991 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1989898

RESUMO

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.


Assuntos
Capilares/fisiologia , Mitocôndrias/fisiologia , Plasticidade Neuronal , Córtex Visual/fisiologia , Animais , Volume Sanguíneo , Neurônios/ultraestrutura , Ratos , Ratos Endogâmicos , Meio Social
18.
Exp Neurol ; 111(1): 74-9, 1991 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1984435

RESUMO

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.


Assuntos
Astrócitos/patologia , Meio Ambiente , Hipocampo/patologia , Estresse Psicológico/patologia , Glândulas Suprarrenais/anatomia & histologia , Animais , Hipertrofia , Masculino , Tamanho do Órgão , Ratos , Sinapses/patologia
19.
Proc Natl Acad Sci U S A ; 87(14): 5568-72, 1990 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1695380

RESUMO

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.


Assuntos
Córtex Cerebelar/fisiologia , Aprendizagem , Atividade Motora , Sinapses/fisiologia , Animais , Vasos Sanguíneos/citologia , Vasos Sanguíneos/fisiologia , Córtex Cerebelar/irrigação sanguínea , Feminino , Neovascularização Patológica , Esforço Físico , Células de Purkinje/citologia , Células de Purkinje/fisiologia , Ratos , Fatores de Tempo
20.
Dev Psychobiol ; 22(7): 727-52, 1989 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2680685

RESUMO

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.


Assuntos
Peso Corporal/fisiologia , Encéfalo/crescimento & desenvolvimento , Aprendizagem/fisiologia , Memória/fisiologia , Estresse Fisiológico/complicações , Glândulas Suprarrenais/crescimento & desenvolvimento , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Desenvolvimento Ósseo , Osso e Ossos/anatomia & histologia , Feminino , Rim/crescimento & desenvolvimento , Fígado/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Distribuição Aleatória , Ratos , Ratos Endogâmicos , Caracteres Sexuais , Baço/crescimento & desenvolvimento , Timo/crescimento & desenvolvimento , Fatores de Tempo
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