An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children.

Children with low aerobic fitness have altered brain function compared to higher-fit children. This study examined the effect of an 8-month exercise intervention on resting state synchrony. Twenty-two sedentary, overweight (body mass index ≥85th percentile) children 8-11 years old were randomly assigned to one of two after-school programs: aerobic exercise (n=13) or sedentary attention control (n=9). Before and after the 8-month programs, all subjects participated in resting state functional magnetic resonance imaging scans. Independent components analysis identified several networks, with four chosen for between-group analysis: salience, default mode, cognitive control, and motor networks. The default mode, cognitive control, and motor networks showed more spatial refinement over time in the exercise group compared to controls. The motor network showed increased synchrony in the exercise group with the right medial frontal gyrus compared to controls. Exercise behavior may enhance brain development in children.

Prolonged activation of NF-kappaB following traumatic brain injury in rats.

Activation of transcription factor, nuclear factor kappa B (NF-kappaB), has been shown to play a key role in inflammatory response, neuronal survival and signaling. We investigated the regional and temporal distribution of activated NF-kappaB in rats at 1 h, 2 h, 24 h, 48 h, 1 week, 2 weeks, 1 month, 2 months, 6 months, and 1 year following brain injury in rats. Early after trauma (1-2 h), activated NF-kappaB was detected in axons, and subsequently found in the cytoplasm and nucleus of neurons by 24 h and lasting up to 1 week. In addition, by 24 h posttrauma, activated NF-kappaB was detected in microglia/macrophages and astrocytes in injured cortex. Surprisingly, this activation persisted for at least 1 year following injury in the cortex, primarily at the margins of progressively enlarging ventricle. Activated NF-kappaB was also detected in endothelial cells, as early as 1 h, and persisted for up to 1 year. These results suggest that a neuronal response to brain trauma includes the activation of NF-kappaB first in the axon with subsequent translocation to the nucleus. Furthermore, these results demonstrate that remarkably prolonged activation of NF-kappaB in glia is found in the same regions undergoing persistent atrophy, suggesting NF-kappaB activation may play a role in long-term inflammatory processes following brain trauma.

Enduring cognitive, neurobehavioral and histopathological changes persist for up to one year following severe experimental brain injury in rats.

Clinical studies have demonstrated that patients sustain prolonged behavioral deficits following traumatic brain injury, in some cases culminating in the cognitive and histopathological hallmarks of Alzheimer's disease. However, few studies have examined the long-term consequences of experimental traumatic brain injury. In the present study, anesthetized male Sprague-Dawley rats (n = 185) were subjected to severe lateral fluid-percussion brain injury (n = 115) or sham injury (n = 70) and evaluated up to one year post-injury for cognitive and neurological deficits and histopathological changes. Compared with sham-injured controls, brain-injured animals showed a spatial learning impairment that persisted up to one year post-injury. In addition, deficits in specific neurologic motor function tasks also persisted up to one year post-injury. Immunohistochemistry using multiple antibodies to the amyloid precursor protein and/or amyloid precursor protein-like proteins revealed novel axonal degeneration in the striatum, corpus callosum and injured cortex up to one year post-injury and in the thalamus up to six months post-injury. Histologic evaluation of injured brains demonstrated a progressive expansion of the cortical cavity, enlargement of the lateral ventricles, deformation of the hippocampus, and thalamic calcifications. Taken together, these findings indicate that experimental traumatic brain injury can cause long-term cognitive and neurologic motor dysfunction accompanied by continuing neurodegeneration.

Twofold overexpression of human beta-amyloid precursor proteins in transgenic mice does not affect the neuromotor, cognitive, or neurodegenerative sequelae following experimental brain injury.

By using transgenic mice that overexpress human beta-amyloid precursor proteins (APPs) at levels twofold higher than endogenous APPs, following introduction of the human APP gene in a yeast artificial chromosome (YAC), we examined the effects of controlled cortical impact (CCI) brain injury on neuromotor/cognitive dysfunction and the development of Alzheimer's disease (AD)-like neuropathology. Neuropathological analyses included Nissl-staining and immunohistochemistry to detect APPs, beta-amyloid (Abeta), neurofilament proteins, and glial fibrillary acidic protein, whereas Abeta levels were measured in brain homogenates from mice subjected to CCI and control mice by using a sensitive sandwich enzyme-linked immunosorbent assay. Twenty APP-YAC transgenic mice and 17 wild type (WT) littermate controls were anesthetized and subjected to CCI (velocity, 5 m/second; deformation depth, 1 mm). Sham (anesthetized but uninjured) controls (n = 10 APP-YAC; n = 8 WT) also were studied. Motor function was evaluated by using rotarod, inclined-plane, and forelimb/hindlimb flexion tests. The Morris water maze was used to assess memory. Although CCI induced significant motor dysfunction and cognitive deficits, no differences were observed between brain-injured APP-YAC mice and WT mice at 24 hours and 1 week postinjury. By 1 week postinjury, both cortical and hippocampal CA3 neuron loss as well as extensive astrogliosis were observed in all injured animals, suggesting that overexpression of human APPs exhibited no neuroprotective effects. Although AD-like pathology (including amyloid plaques) was not observed in either sham or brain-inj ured animals, a significant decrease in brain concentrations of only Abeta terminating at amino acid 40 (Abeta x-40) was observed following brain injury in APP-YAC mice (P < 0.05 compared with sham control levels). Our data show that the APP-YAC mice do not develop AD-like neuropathology following traumatic brain injury. This may be because this injury does not induce elevated levels of the more amyloidogenic forms of human Abeta (i.e., Abeta x-42/43) in these mice.

Progressive atrophy and neuron death for one year following brain trauma in the rat.

Although atrophic changes have been well described following traumatic brain injury (TBI) in humans, little is known concerning the mechanisms or progression of brain tissue loss. In the present study, we evaluated the temporal profile of histopathological changes following parasagittal fluid-percussion (FP) brain injury in rats over 1 year postinjury. Anesthetized 3-4 month-old Sprague-Dawley Rats (n = 51) were subjected to FP brain injury of high severity (2.5-2.9 atm, n = 51) or sham treatment (n = 27). At 1 h, 2 h, 48 h, 1 week, 2 weeks, 1 month, 2 months, 6 months and 1 year after brain injury or sham treatment, these animals were humanely euthanized. Brain sections were analyzed with image-processing techniques to determine the extent of cortical tissue loss and shrinkage of the hippocampal pyramidal cell layer. In addition, cell counting was performed to determine the number of neurons in the dentate hilus of the hippocampus, and glial fibrillary acidic protein (GFAP) immunostaining was used to reveal reactive astrocytosis. Examination of the injured brains revealed substantial and progressive tissue loss with concomitant ventriculomegaly in the hemisphere ipsilateral to injury. The regions with the most notable progressive atrophy included the cortex, hippocampus, thalamus, and septum. Quantitative analysis demonstrated a significantly progressive loss of cortical tissue as well as shrinkage of the hippocampal pyramidal cell layer ipsilateral to injury over 1 year following injury. In addition, reactive astrocytosis in regions of atrophy and progressive bilateral death of neurons in the dentate hilus was observed for 1 year following injury. These results suggest that a chronically progressive degenerative process may be initiated by brain trauma. Thus, there is a temporally broad window within which to introduce novel therapeutic strategies designed to ameliorate the short and long-term consequences of brain trauma.

Rational design of an animal model for Alzheimer's disease: introduction of multiple human genomic transgenes to reproduce AD pathology in a rodent.

A major obstacle to understanding the pathogenesis of Alzheimer's disease is the lack of easily studied animal models. Our approach is to apply transgenic methods to humanize mice and rats, employing methods that introduce large genomic transgenes, because this improves the level of transgene protein expression and the tissue specificity of expression. Our plan is to reproduce AD pathology in rodents by making them transgenic for several human proteins involved in AD. This report describes transgenic animal lines that we have produced, and summarizes our current approach and future plans. Two human genes known to be involved in AD pathology are the amyloid precursor protein (APP) and the E4 isoform of apolipoprotein E (apoE4). So far, we have produced and analyzed a transgenic line carrying the entire human APP gene cloned in a yeast artificial chromosome. We have also produced but not yet analyzed a mouse carrying the human apoE4 gene. Work is in progress to produce a transgenic line carrying a disease-causing mutation in the human APP gene. As we produce these animals, we are breeding them together, and also breeding them with a mouse line that lacks endogenous apoE, to produce an animal model carrying several human proteins whose interaction is believed to be instrumental in development of AD pathology. These transgenic animals will be useful for dissecting the biochemical and physiological steps leading to AD, and for development of therapies for disease intervention.

Immunohistochemical characterization of alterations in the distribution of amyloid precursor proteins and beta-amyloid peptide after experimental brain injury in the rat.

Recent reports suggest a relationship between traumatic brain injury and the precocious development of neurodegenerative cascades, including diffuse deposits of beta-amyloid peptides (A beta) in the injured brain. Because the lateral fluid-percussion (FP) model of experimental brain injury produces clinically relevant neuropathological sequelae in the rat brain, we used this model together with a series of antibodies specific for amyloid precursor proteins (APPs), APP-like proteins (APLPs), or A beta to identify acute neurodegenerative changes after brain trauma. Male Sprague-Dawley rats were anesthetized and subjected to lateral FP brain injury of moderate to high severity. At 1 hr, 2 hr, 48 hr, 1 week, or 2 weeks after injury, animals were killed and their brains were removed for immunohistochemical analysis. APP/APLP immunoreactivity increased in specific brain regions as early as 1 hr after injury and persisted for at least 2 weeks. Axons in the thalamus and subcortical white matter showed the greatest APP/APLP accumulation. Injured cortex, striatum, cingulum, and hippocampus also demonstrated significant axonal accumulations of APP/APLP. Accumulation of APP/APLPs occurred primarily ipsilateral to the injury, although bilateral changes were observed in some brain regions. No deposition of A beta was observed in any brain region at any time point examined. These results demonstrate a pattern of widespread axonal pathology after lateral FP brain injury in the rat, characterized by intra-axonal accumulations of APP/APLP immunoreactivity in the absence of plaque-like deposits of A beta in the traumatized brain.

A longitudinal study of the impact of changing public policy on community mental health client residential patterns and staff attitudes.

Three studies of perceived residential needs and community residential patterns of adults with severe and persistent mental illness over a period of 12 years are used to assess the effect of changing public policy in this area. During a period in which public policy shifted from advocacy of congregate living in treatment settings to independent living in generic community housing, there were significant changes in community residential patterns and in the attitudes of case managers. Clinical and demographic data collected in the most recent survey provides a much more complete profile of the community living situation of adults with severe and persistent mental illness than was previously available.

The nootropic compound BMY-21502 improves spatial learning ability in brain injured rats.

Although long-lasting cognitive dysfunction often follows clinical traumatic brain injury (TBI), few pharmacologic regimens have been developed to treat post-traumatic cognitive deficits. We have previously shown that, in the rat, experimental lateral fluid-percussion (FP) brain injury induces a profound impairment in retrograde memory. In the present study, we characterized alterations in the ability of rats to learn a novel task following lateral FP brain injury and examined the potential modulatory effects of the nootropic cognitive enhancer BMY-21502 on post-injury learning. Male Sprague-Dawley rats were subjected to lateral (parasagittal) FP brain injury of moderate severity (2.4 atm) or sham surgery (no injury). On days 7 and 8 post-injury, animals were tested in a Morris water maze for their ability to learn to navigate to a submerged, invisible platform using external visual cues. BMY-21502 (10 mg/kg) or vehicle was administered 30 min prior to the first trial on both days. A highly significant (P < 0.001) impairment in post-injury learning was observed in vehicle-treated brain-injured animals compared with vehicle-treated sham animals. Injured animals treated with BMY-21502 at one week post-injury showed significantly (P < 0.05) improvement in post-injury learning ability compared to injured animals treated with vehicle. Paradoxically, in uninjured control animals BMY-21502 treatment appeared to worsen learning scores. The results of this study indicate that BMY-21502 may be useful for attenuating the dysfunction in learning ability that occurs following TBI.

Augmentation of lung antineutrophil elastase capacity with recombinant human alpha-1-antitrypsin.

To evaluate the potential use of recombinant DNA-produced alpha-1-antitrypsin (alpha-1-AT) to augment the lung antineutrophil elastase defenses in alpha-1-AT deficiency, we compared the kinetics of intravenously administered recombinant produced alpha-1-AT (r alpha-1-AT) and purified normal human plasma alpha-1-AT (p alpha-1-AT) in the blood and lung of rhesus monkeys. The r alpha-1-AT was produced in yeast transformed with an expressing plasmid containing a full-length human alpha-1-AT complementary deoxyribonucleic acid and purified to greater than 99% homogeneity. The r alpha-1-AT has a molecular weight of 45,000, no carbohydrates, and is identical in sequence to normal plasma alpha-1-AT except for an additional N-terminal acetylmethionine. Despite its lack of carbohydrates, the r alpha-1-AT inhibited human neutrophil elastase with an association rate constant similar to that of p alpha-1-AT. Rhesus monkeys were infused intravenously with 120 mg/kg of r alpha-1-AT (n = 13) or p alpha-1-AT (n = 12) and the serum, urine, and lung epithelial lining fluid (ELF) concentrations of these molecules quantified at various intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) shortens the period of neutropenia after autologous bone marrow transplantation in a primate model.

The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on hematopoietic reconstitution after autologous bone marrow transplantation was evaluated in a primate model. Animals were given a continuous intravenous infusion of recombinant human GM-CSF for several days both before and after transplantation or only after the transplant procedure. Marrow ablation was accomplished by total body irradiation. In both groups of animals, the neutrophil count reached 1,000/mm3 by 8-9 d posttransplant compared with an interval of 17 and 24 d for two concurrent controls. After withdrawal of GM-CSF, neutrophil counts fell to values comparable to those observed in untreated controls. Accelerated recovery of platelet production was also observed in four of the five animals. Two additional animals were initially given GM-CSF several weeks posttransplantation because of inadequate engraftment. Prompt and sustained increases in neutrophil and platelet counts were observed. We conclude that GM-CSF may be useful in accelerating bone marrow reconstitution.

A familial basis for the heterogeneity in coronary atherosclerotic disease.

Miniature swine fed a high-cholesterol, high-fat diet demonstrated heterogeneity in the extent of coronary artery disease. Plasma cholesterol or lipoprotein concentrations as well as other known risk factors accounted for little of this heterogeneity. However, the majority of the variability could be accounted for by the familial predisposition to develop cardiovascular disease in the individual animal kindreds. This study strongly suggests that the enhanced rate of development of coronary atherosclerotic disease during hypercholesterolemia is more critically modulated by previously unrecognized genetic actors than by absolute plasma cholesterol concentrations.

Low density lipoprotein modulation of porcine coronary artery contractile response to histamine.

Right coronary artery ring segments from miniature swine contracted to histamine with a force and sensitivity comparable to that reported for human right coronary artery ring segments. When the ring segments were suspended in preparations of human low density lipoprotein (LDL) the contractility was reduced. With denuded rings the contractility was significantly lower in the LDL at 1.1 X 10(-4) M histamine. With intact rings significantly less tension was generated in the LDL at concentrations greater than 6 X 10(-5) M histamine. Thus LDL attenuates the contractile response of the porcine right coronary artery to histamine.

Enhancement of lung conditioning by acetylcholine in the prevention of respiratory distress syndrome in the preterm fetal lamb.

We exposed 128- to 130-day-gestation fetal lambs by cesarean section leaving the umbilical cord and placenta undisturbed, and we then treated the lungs with pulmonary conditioning (i.e., repeated prolonged inflations to 35 cm H2O, followed by a continuous positive airway pressure of 15 cm H2O). To investigate the added effect of pulmonary vasodilation upon the increase of total compliance and pulmonary oxygen uptake, we also administered acetylcholine intravenously at a rate of 80 micrograms min-1. Eleven of 13 lambs met the endpoint criteria of either compliance (0.5 ml [cm H2O]-1 kg-1; 1 animal), or pulmonary oxygen uptake (6 ml kg-1 min-1; 6 animals), or both (4 animals), and were delivered within 0.6 +/- 0.3 h. This time was significantly (p less than 0.05) shorter than previously seen in similar studies without the infusion of a vasodilator; all animals so delivered survived 24 h of mechanical ventilation in excellent health. We suggest that pharmacologic pulmonary vasodilation, in addition to deep sustained pulmonary insufflation and distension, is an effective and rapid means of transforming stiff immature lungs into lungs that can sustain normal ventilation and gas exchange.

Successful treatment of experimental neonatal respiratory failure using extracorporeal membrane lung assist.

A total of 44 preterm fetal lambs at great risk of developing respiratory failure were delivered by Cesarean section, and were then managed on conventional mechanical pulmonary ventilation. Fifteen animals initially fared well, and 14 of these were long term survivors. Twenty-nine other lambs showed a progressive deterioration in arterial blood gases within 30 minutes of delivery, of which 10 lambs were continued on mechanical pulmonary ventilation (20% survival), while the remaining 19 lambs were placed on an extracorporeal membrane lung respiratory assist (79% survival). Extracorporeal membrane lung bypass rapidly corrected arterial blood gas values, and permitted the use of high levels of CPAP instead of the continuation of mechanical pulmonary ventilation at high peak airway pressures. Improvement in lung function was gradual, and predictable. Early institution of extracorporeal respiratory assist using a membrane artificial lung rapidly corrected arterial blood gas values and significantly improved on neonate survival.

Prediction of gradients in fibrous subaortic stenosis by continuous wave two-dimensional Doppler echocardiography: animal studies.

The purpose of this study was to assess the accuracy of continuous wave, two-dimensional Doppler echocardiography for predicting pressure gradients across discrete subaortic stenoses. Twenty-three Newfoundland dogs with subaortic stenosis were studied by closed chest Doppler interrogation of aortic velocity from an apical view of the left ventricular outflow tract simultaneously with measurements of pressure gradient during cardiac catheterization. Continuous mode Doppler interrogation was used with two-dimensional echographic guidance (Irex model IIIB) to compare the Doppler-derived maximal velocity with the pressure gradient across the obstruction at rest and after provocation with amyl nitrite inhalation and isoproterenol infusion. The maximal velocities recorded by Doppler ranged from 98 to 539 cm/s and correlated with hemodynamic gradients ranging from 3 to 123 mm Hg (r = 0.92, SEE = 37 cm/s). Doppler velocities were converted to gradients using a simplification of the Bernoulli relation (gradient = 4 X maximal velocity2); the resulting Doppler-derived gradients also correlated closely with the catheterization-measured pressure gradients (r = 0.95, SEE = 7.1 mm Hg). The predictive capability of Doppler echocardiography for estimating the pressure gradient across fibromuscular subaortic obstructions in this group of dogs with a spectrum of disease similar to that found in human beings was validated. The results also indicate that Doppler methods may have clinical applications in patients with subaortic stenosis.

Ovine pineal alpha 1-adrenoceptors: characterization and evidence for a functional role in the regulation of serum melatonin.

Plasma melatonin in sheep increases to nocturnal levels rapidly (10-20 min) after dark onset. This increase is blocked by iv prazosin (1 mg), but not propranolol (6 mg). Prazosin also blocks the elevation in pineal melatonin content after dark onset, but does not significantly alter the rise in N-acetyltransferase activity or the elevation in pineal N-acetylserotonin content. Since the nocturnal elevation in N-acetyltransferase, a neurally regulated event, was unaltered, this suggests that prazosin does not significantly impair the transmission of neural signals from the eye to the gland, but does act on pineal alpha 1-adrenoceptors to block melatonin production. This is supported by binding studies in ovine pineal membranes using [125I] iodo-2-[beta-(4-hydroxyphenyl)ethylaminomethyl]tetralone, which revealed that binding is rapid, reversible, saturable, and stereo-specific. Saturation studies indicated the presence of a single class of binding sites, with an equilibrium binding constant (Kd) of 32 +/- 6 pM and a maximum binding of 139 +/- 19 fmol/mg protein. The relative potencies of several adrenergic agonists and antagonists in competition studies indicated that the receptor belongs to the alpha 1-subclass of adrenoceptors. Together, these data suggest that melatonin synthesis in the sheep pineal gland is controlled in part by an alpha 1-adrenoceptor mechanism at a step beyond N-acetylation.

Respiratory distress syndrome in immature lambs. Prevention through antenatal accelerated conditioning of the lung.

We tested the effectiveness of constant distending pressure applied to immature lungs in preventing respiratory distress syndrome. Fetal lambs of 131 to 134 days gestation were delivered by cesarean section, but the umbilical circulation was kept intact for CO2 removal through the natural in situ placenta. The lungs were inflated to a pressure of 35 cm H2O (Group I, 11 animals) or 25 cm H2O (Group II, 14 animals), after which the airway pressure was maintained at 15 cm H2O through apneic oxygenation until total static compliance exceeded 0.5 ml (cm H2O)- 1kg -1. After a mean of 1.1 and 5.7 h, respectively, the animals were delivered and were given mechanical ventilation for 24 h. Twenty-four animals reached this aimed-for compliance and survived the period of mechanical ventilation in excellent health. A control group of fetal lambs was delivered immediately and treated with mechanical ventilation. Three of 10 control animals developed severe respiratory distress syndrome and died; 1 additional animal survived but with central nervous system involvement from severe hypoxia. We conclude that pulmonary inflation to 35 cm H2O pressure, followed by a constant distending pressure of 15 cm H2O, held until compliance reaches 0.5 ml (cm H2O)- 1kg -1, is an important element in the prevention of respiratory distress syndrome.