Increased activity and phase delay in circadian motility rhythms in geriatric depression. Preliminary observations.

Locomotor activity levels and rhythms of eight hospitalized geriatric unipolar depressed patients (DSM-III criteria) were compared with those of eight healthy elderly controls in a similar environment. Activity was measured using a wrist-worn electronic activity monitor with solid-state memory. Depressed patients had a 29% higher mean total 24-hour activity level, with no change in circadian amplitude or frequency. Daily peak activity (acrophase) averaged 2.05 hours later in depressed patients, with no overlap between the groups. The degree of phase delay correlated significantly with the 4 PM postdexamethasone serum cortisol level. These tentative findings suggest that elderly unipolar depressed patients have prominent chronobiological disturbances in the modulation of activity levels and possibly other physiological processes. These differ strikingly from reported disturbances in younger or bipolar depressed patients.

Basic fibroblast growth factor protects against hypoxia-ischemia and NMDA neurotoxicity in neonatal rats.

Basic fibroblast growth factor (bFGF) is a polypeptide that promotes neuronal survival and blocks excitatory amino acid (EAA) neurotoxicity in vitro at very low concentrations. In the present study, we examined whether systemically administered bFGF could prevent neuronal damage induced by either EAAs or hypoxia-ischemia in vivo. Neuroprotective effects were examined in a neonatal model of hypoxia-ischemia (unilateral ligation of the carotid artery followed by exposure to 8% oxygen for 1.5 h) and following intrastriatal injection of N-methyl-D-aspartate (NMDA) in 7-day-old rats. Intraperitoneal administration of a single dose of bFGF (50-300 micrograms/kg) 30 min before intrastriatal injection of NMDA showed a dose-dependent neuroprotective effect. Repeated doses of bFGF (100 micrograms/kg) both before and after intrastriatal NMDA injection produced a much greater significant protective effect than a single dose administered prior to the injection. Intraperitoneal injection of single dose of 100 micrograms/kg of bFGF 30 min before hypoxia-ischemia reduced neuronal damage by 38% (p = 0.14), while administration of bFGF at a dose of 100 micrograms/kg i.p. three times, 30 min before and 0 and 30 min after hypoxia-ischemia, significantly reduced neuronal damage by 64% (p = 0.004). Systemic administration of bFGF did not change body temperature for up to 3 h. These results show that systemic administration of bFGF can exert neuroprotective effects against both NMDA-induced excitotoxicity and hypoxia-ischemia in vivo.

Intracisternal basic fibroblast growth factor (bFGF) enhances behavioral recovery following focal cerebral infarction in the rat.

Basic fibroblast growth factor (bFGF) is a potent neurotrophic agent that promotes neuronal survival and outgrowth. Previous studies have shown that bFGF, administered intraventricularly or intravenously before or within hours after ischemia, reduces infarct size and neurological deficits in models of focal cerebral ischemia in rats. In the current study, we tested the hypothesis that bFGF, administered at later time points after ischemia, might improve behavioral recovery without affecting infarct size. Mature Sprague-Dawley rats received bFGF (1 microgram/injection) or vehicle by biweekly intracisternal injection for 4 weeks, starting at 1 day following permanent proximal middle cerebral artery (MCA) occlusion. Animals were examined every other day using four different behavioral tests to assess sensorimotor and reflex function. At 4 weeks after ischemia, there was no difference in infarct volume between bFGF- and vehicle-treated animals. There was, however, an enhancement in the rate and degree of behavioral recovery among bFGF-treated animals, as measured by all four tests. There were no apparent side effects of bFGF treatment, except that bFGF-treated animals tended to recover body weight more slowly than did vehicle-treated animals following stroke. The mechanisms of enhancement of behavioral recovery by bFGF require further study, but may include protection against retrograde neuronal death and/or stimulation of neuronal sprouting.

Delayed treatment with intravenous basic fibroblast growth factor reduces infarct size following permanent focal cerebral ischemia in rats.

Basic fibroblast growth factor (bFGF) is a polypeptide that supports the survival of brain cells (including neurons, glia, and endothelia) and protects neurons against a number of toxins and insults in vitro. This factor is also a potent dilator of cerebral pial arterioles in vivo. In previous studies, we found that intraventricularly administered bFGF reduced infarct volume in a model of focal cerebral ischemia in rats. In the current study, bFGF (45 micrograms/kg/h) in vehicle, or vehicle alone, was infused intravenously for 3 h, beginning at 30 min after permanent middle cerebral artery occlusion by intraluminal suture in mature Sprague-Dawley rats. After 24 h, neurological deficit (as assessed by a 0- to 5-point scale, with 5 = most severe) was 2.6 +/- 1.0 in vehicle-treated and 1.5 +/- 1.3 in bFGF-treated rats (mean +/- SD; N = 12 vs. 11; p = 0.009). Infarct volume was 297 +/- 65 mm3 in vehicle- and 143 +/- 135 mm3 in bFGF-treated animals (p = 0.002). During infusion, there was a modest decrease in mean arterial blood pressure but no changes in arterial blood gases or core or brain temperature in bFGF-treated rats. Autoradiography following intravenous administration of 111In-labeled bFGF showed that labeled bFGF crossed the damaged blood-brain barrier to enter the ischemic (but not the nonischemic) hemisphere. Whether the infarct-reducing effects of bFGF depend on intraparenchymal or intravascular mechanisms requires further study.

Basic fibroblast growth factor dilates rat pial arterioles.

Basic fibroblast growth factor (bFGF) is a polypeptide that promotes the survival and differentiation of brain neurons, glia, and endothelial cells. It has been shown recently that intravenously administered bFGF lowers blood pressure by systemic vasodilation; this effect is mediated, in part, by nitric oxide (NO)-dependent mechanisms. In the current study, we directly evaluated the effect of bFGF on pial arterioles of pentobarbital-anesthetized Sprague-Dawley rats (n = 18) using the closed cranial window technique. Basic FGF (5-200 ng/ml) produced dose-dependent vasodilation; maximal vessel diameter (approximately 120% of control) was reached at 100 ng/ml. No vasodilation was found when bFGF was heat inactivated, or preincubated with blocking antibody. Moreover, bFGF-induced vasodilation was attenuated by coadministration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), consistent with an NO-dependent mechanism. These results suggest that bFGF may play an important role in the regulation of cerebrovascular tone and cerebral blood flow.

Estradiol protects against ischemic injury.

Clinical studies demonstrate that estrogen replacement therapy in postmenopausal women may enhance cognitive function and reduce neurodegeneration associated with Alzheimer's disease and stroke. This study assesses whether physiologic levels of estradiol prevent brain injury in an in vivo model of permanent focal ischemia. Sprague-Dawley rats were ovariectomized; they then were implanted, immediately or at the onset of ischemia, with capsules that produced physiologically low or physiologically high 17beta-estradiol levels in serum (10 or 60 pg/mL, respectively). One week after ovariectomy, ischemia was induced. Estradiol pretreatment significantly reduced overall infarct volume compared with oil-pretreated controls (mean+/-SD: oil = 241+/-88; low = 139+/-91; high = 132+/-88 mm3); this protective effect was regionally specific to the cortex, since no protection was observed in the striatum. Baseline and ischemic regional CBF did not differ between oil and estradiol pretreated rats, as measured by laser Doppler flowmetry. Acute estradiol treatment did not protect against ischemic injury. Our finding that estradiol pretreatment reduces injury demonstrates that physiologic levels of estradiol can protect against neurodegeneration.

Comparison of MRI and CT scans in a group of psychiatric patients.

The authors compared the results of computerized tomography (CT) and magnetic resonance imaging (MRI) scans of 16 psychotic patients with various diagnoses whose neurologic examinations suggested structural brain abnormalities. Blind readings showed a high concordance of findings, including ventricle-to-brain ratios, although MRI appeared superior in visualizing midline structures and identifying atrophic changes. Because it requires no ionizing radiation, MRI allows multiple studies of the same patient, study of family members, and recruitment of unbiased samples of control subjects. Use of MRI may help address questions regarding the specificity and prevalence of brain abnormalities observed with CT in psychotic patients.

Petechial hemorrhages accompanying lobar hemorrhage: detection by gradient-echo MRI.

Based on the pathologic observation that severe cerebral amyloid angiopathy is often accompanied by multiple petechial hemorrhages, we prospectively obtained gradient-echo MRI on 15 elderly patients with lobar hemorrhage on CT. Nine of the 15 demonstrated accompanying petechial hemorrhages restricted to the cortical or corticosubcortical regions. No similar lesions were present on gradient-echo MRI in 10 elderly control patients. These findings suggest that cerebral amyloid angiopathy might be neuroradiologically diagnosed and staged during life.

The clinical spectrum of cerebral amyloid angiopathy: presentations without lobar hemorrhage.

Cerebral amyloid angiopathy is a common cause of spontaneous lobar hemorrhage in elderly patients. We discuss seven patients with amyloid angiopathy presenting without major lobar hemorrhage. The patients' presentations fell into two groups: recurrent transient neurologic symptoms and rapidly progressive dementia. The cases with transient episodes had a spread of symptoms to contiguous body areas during episodes. Each had evidence of small hemorrhage or subsequent large hemorrhage in the cortical location corresponding to the symptoms, suggesting petechial hemorrhage with focal seizure as the cause of the transient spells. Three cases of dementia developed with relatively rapid time courses, progressing from intact baseline to profound dementia in spans of a few days to 2 years. Pathologic abnormalities, in addition to amyloid angiopathy, included patchy white matter demyelination and tissue loss, petechial cortical hemorrhages, cortical infarctions, and a variable degree of neuritic plaques and neurofibrillary tangles. The clinical spectrum of cerebral amyloid angiopathy includes these two neurologic syndromes.

Time window of intracisternal osteogenic protein-1 in enhancing functional recovery after stroke.

Osteogenic protein-1 (OP-1, BMP-7) is a member of the bone morphogenetic protein subfamily of the TGF-ss superfamily that selectively stimulates dendritic neuronal outgrowth. In previous studies, we found that the intracisternal injection of OP-1, starting at one day after stroke, enhanced sensorimotor recovery of the contralateral limbs following unilateral cerebral infarction in rats. In the current study, we further explored the time window during which intracisternal OP-1 enhances sensorimotor recovery, as assessed by limb placing tests. We found that intracisternal OP-1 (10 microg) given 1 and 3 days, or 3 and 5 days, but not 7 and 9 days after stroke, significantly enhanced recovery of forelimb and hindlimb placing. There was no difference in infarct volume between vehicle- and OP-1-treated animals. The mechanism of OP-1 action might be stimulation of new dendritic sprouting in the remaining uninjured brain.

Myocyte-specific enhancer binding factor 2C expression in gerbil brain following global cerebral ischemia.

Myocyte-specific enhancer binding factor 2 (MEF2C) is a transcription factor expressed at high levels in brain. In this study, the distribution of MEF2C expression in brain was studied in normal adult gerbils and in adult gerbils subjected to 10 min of global cerebral ischemia. In normal animals, MEF2C-immunoreactivity and messenger RNA expression were detected in cortex, hippocampus, caudate-putamen, thalamus, hypothalamus, and amygdala. Within the hippocampus, MEF2C-immunoreactivity and MEF2C messenger RNA were found in interneurons scattered through the CA fields, a subset of which are parvalbumin-immunoreactive. MEF2C-immunoreactivity and MEF2C messenger RNA were also present in granule cells in the dentate gyrus. MEF2C-immunoreactivity was also detected in microglia in the hippocampus. After transient forebrain ischemia, CA1 pyramidal neurons, which are MEF2C-negative, degenerate whereas MEF2C-positive interneurons survive. Our results thus indicate that MEF2C is a marker for hippocampal neurons that are resistant to ischemia. It remains to be determined whether MEF2C plays a direct role in protecting the neurons that express it from ischemic injury. In addition, MEF2C-immunoreactivity is present in microglia, and, after ischemia, there were increased numbers of MEF2C-immunoreactive microglia in CA1, so MEF2C-immunoreactivity is a marker of both resting and activated microglia.

Intravenous basic fibroblast growth factor (bFGF) decreases DNA fragmentation and prevents downregulation of Bcl-2 expression in the ischemic brain following middle cerebral artery occlusion in rats.

In previous studies, we showed that basic fibroblast growth factor (bFGF) reduced infarct volume when infused intravenously in animal models of focal cerebral ischemia. In the current study, we examined the potential mechanism of infarct reduction by bFGF, especially effects on apoptosis within the ischemic brain. We found that bFGF decreased DNA fragmentation in the ischemic hemisphere, as assessed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) histochemical methods combined with morphological criteria. bFGF also prevented reduction of immunoreactivity of the anti-apoptotic protein Bcl-2 in the ischemic hemisphere, but did not alter immunoreactivity of the pro-apoptotic proteins Bax, Caspase-1, or Caspase-3. These changes in TUNEL histochemistry and Bcl-2 immunoreactivity were especially prominent in cortex at the borders ('penumbra') of infarcts, spared by bFGF treatment. We conclude that the infarct-reducing effects of bFGF may be due, in part, to prevention of downregulation of Bcl-2 expression and decreased apoptosis in the ischemic brain.

Increased expression of basic fibroblast growth factor (bFGF) following focal cerebral infarction in the rat.

Basic fibroblast growth factor (bFGF) is a polypeptide with potent trophic effects on brain neurons, glia, and endothelial cells. In the current study, we used Northern blotting, in situ hybridization, and immunohistochemical techniques to examine bFGF expression in brain following focal infarction due to permanent occlusion of the proximal middle cerebral artery in mature Sprague-Dawley rats. We found a four-fold increase in bFGF mRNA in tissue surrounding focal infarcts at 1 day after ischemia. In situ hybridization showed that this increase was found throughout several structures in the ipsilateral hemisphere, including frontoparietal, temporal, and cingulate cortex, as well as in caudoputamen, globus pallidus, septal nuclei, nucleus accumbens, and olfactory tubercle. Increased bFGF mRNA expression was associated with cells having the distinct morphological appearance of astroglia in these structures. Immunohistochemistry showed an increase in the size and number of bFGF-immunoreactive (IR) nuclei in these same structures, as well as a shift from nuclear to nuclear plus cytoplasmic localization of immunoreactivity, beginning at 1 day, and peaking at 3 days after ischemia. Double immunostaining identified bFGF-IR cells as astroglia in these structures. (An exception was the piriform cortex, in which both increased bFGF mRNA levels and increased bFGF-IR was found in neurons at 1 day after ischemia). Overall, the peak of increased bFGF expression preceded the peak in expression of the astroglial marker GFAP within the ipsilateral hemisphere. Increased bFGF expression may play an important role in the glial, neuronal, and vascular changes occurring after focal infarction.

Temporal, differential and regional expression of mRNA for basic fibroblast growth factor in the developing and adult rat brain.

The expression of basic fibroblast growth factor (bFGF) mRNA and bFGF receptor mRNA was investigated in developing rat brain. In embryonic rat brain days 13-21 (E13-E21), an abundant 1.8 kb bFGF mRNA was detected. Expression of 1.8 kb bFGF mRNA was the highest at E17 to E19 and was relatively undetectable 20 days after birth. However, very little mitogenic activity was associated with prenatal brain. On the other hand, multiple bFGF mRNA species of 6.0, 3.7, 2.5, 1.8, 1.6, 1.4 and 1.0 kb were detected in total adult rat brain and a significant amount of mitogenic activity was present. Differential and spatial bFGF mRNA expression was found in different parts of developing rat brain. Embryonic hypothalamus was found to contain the 1.8 kb bFGF mRNA while the 6.0 kb bFGF mRNA transcript was predominant in adult hypothalamus. Adult pituitary and cortex transcribed the lower molecular weight mRNAs but not the 6.0 kb mRNA. Expression of high-affinity bFGF receptor (flg) mRNA was found to be temporally regulated. flg 4.3 kb mRNA expression was high in embryonic rat brain (E13-E19). There appears to be coordinate expression between the 1.8 kb bFGF mRNA and flg. These results suggest that the expression of basic FGF mRNA is complex since it is both temporally and differentially regulated with different species being expressed at different times in development.

Partial purification and characterization of a neurite-promoting factor from the injured goldfish optic nerve.

We have partially purified and characterized a neurite-promoting factor derived from the injured goldfish optic nerve (ON). This factor is secreted into conditioned media (CM) by the injured, but not intact goldfish ON, and has potent outgrowth-promoting effects on neurons of the embryonic mammalian brain. Based on its elution properties on ion-exchange and gel-filtration chromatography, this factor appears to be an acidic protein of Mr ca. 26 kilodaltons (kDa) that is distinct from previously characterized growth factors with described effects on mammalian CNS neurons.

Posttreatment with intravenous basic fibroblast growth factor reduces histopathological damage following fluid-percussion brain injury in rats.

The purpose of this study was to determine whether treatment with intravenous basic fibroblast growth factor (bFGF) would protect histopathologically in a rat model of traumatic brain injury (TBI). Twenty-four hours prior to TBI, the fluid-percussion interface was positioned parasagittally over the right cerebral cortex. On the second day, fasted rats were anesthetized with 70% nitrous oxide, 1% halothane, and 30% oxygen. Under controlled physiological conditions and normothermic brain temperature (37-37.5 degrees C), rats were injured with a fluid-percussion pulse ranging from 1.6 to 1.9 atm. Rats were randomized into two groups where either bFGF (45 micrograms/kg/h) in vehicle (n = 7) or vehicle alone (n = 7) was infused intravenously for 3 h, beginning 30 min after TBI. Three days later, brains were perfusion-fixed for histopathological assessment and quantitative analysis of contusion volume and numbers of necrotic cortical neurons. In vehicle-treated animals, necrotic neurons were observed throughout the lateral cerebral cortex remote from the impact site. In addition, an intracerebral contusion was present in all rats at the gray-white interface underlying the injured cortical areas. Posttraumatic administration of bFGF significantly reduced the numbers of damaged cortical neuron profiles at several coronal levels and reduced the total number of damaged neurons (696 +/- 148 vs. 1,248 +/- 198, means +/- SEM), p < 0.05, ANOVA). In addition, contusion ares at several coronal levels as well as total contusion volume was significantly reduced (1.13 +/- 0.39 mm(3) vs. 3.18 +/- 0.81 mm(3), p < 0.05). These data demonstrate neuroprotection with intravenous bFGF infusion in the posttraumatic setting.

Delayed administration of basic fibroblast growth factor (bFGF) attenuates cognitive dysfunction following parasagittal fluid percussion brain injury in the rat.

The present study evaluates the therapeutic effects of delayed administration of bFGF on cognitive dysfunction and histopathological damage following lateral fluid-percussion (FP) brain injury. Male Sprague-Dawley rats were trained to learn a visuospatial task in a Morris Water Maze (MWM) paradigm and then were anesthetized and subjected to either FP brain injury of moderate severity (2.5-2.8 atm, n = 32) or surgery without brain injury (n = 10). Twenty-four hours postinjury, an infusion cannula connected to a mini-osmotic pump was implanted into the area of maximal cortical injury to continuously infuse either bFGF (2.0 g) or vehicle for 7 days. Treatment with bFGF significantly attenuated posttraumatic memory dysfunction in the MWM at 8 days postinjury when compared to vehicle treatment (p < 0.05). The cortical lesion and significant cell loss in the ipsilateral CA3 region of the hippocampus, produced by FP injury, was not affected by bFGF treatment. However, immunohistochemical evaluation of glial fibrillary acidic protein revealed a trend toward increased astrocytosis in the injured cortex of bFGF-treated animals compared to vehicle-treated animals (p < 0.1). These results indicate that bFGF may be efficacious in attenuating cognitive dysfunction associated with traumatic brain injury.

Increased levels of basic fibroblast growth factor (bFGF) following focal brain injury.

Focal injury to the mammalian central nervous system (CNS) results in a cascade of cellular responses - including glial and capillary proliferation and neural sprouting - that contribute to the repair of neural tissue and to the recovery of neurological function. Fibroblast growth factors (FGFs) are heparin-binding polypeptides with potent trophic effects on CNS glia, endothelia, and neurons; both acidic and basic forms are found in the mammalian CNS. We used heparin-affinity chromatography coupled to Balb/c 3T3 mitogenic assay to show a marked increase in levels of bioactive FGFs in tissue surrounding focal cortical lesions of the mature rat brain at one week after injury. Heparin-affinity HPLC showed that this increase was due to a large increase in levels of basic FGF (bFGF), and a much smaller increase in levels of acidic FGF (aFGF) after injury. Increased bFGF bioactivity was paralleled by increased levels of immunoreactive bFGF, as assessed by Western blotting techniques. Increased bFGF levels may play an important role in the cascade of cellular reactions occurring after focal brain injury.

Intracisternal osteogenic protein-1 enhances functional recovery following focal stroke.

Osteogenic protein-1 (OP-1, BMP-7) is a member of the transforming growth factor-beta (TGF-beta) superfamily that selectively induces dendritic outgrowth from cultured neurons. We injected human recombinant OP-1 (1 or 10 micrograms) or vehicle into the cisterna magna of mature male Sprague-Dawley rats 1 and 4 days after focal cerebral infarction induced by middle cerebral artery (MCA) occlusion. OP-1 treatment was associated with a marked enhancement of recovery of sensorimotor function of the impaired forelimb and hindlimb (contralateral to infarcts) as assessed by limb placing tests. This effect appeared to be dose dependent. There was no difference in infarct volume between OP-1 and vehicle-treated rats. The mechanisms of enhanced recovery by intracisternal OP-1 may include promotion of dendritic sprouting in the intact uninjured brain.

Basic fibroblast growth factor enhances axonal sprouting after cortical injury in rats.

The trophic factors responsible for initiating and guiding the outgrowth of axons have proven to be elusive throughout most of this century. Entorhinal cortex injury, which denervates the hippocampal formation of rats, induces axonal sprouting by several surviving hippocampal afferents and results in a significant elevation of growth factors, one of which is basic fibroblast growth factor (bFGF). The possibility that bFGF may regulate lesion-induced hippocampal sprouting was examined by making i.v. bFGF infusions into rats with unilateral entorhinal lesions. Basic FGF treatment significantly increased sprouting by the cholinergic septodentate pathway. Thus, the increase in bFGF following central nervous system injury may signal its role in the regulation of injury-related axonal remodeling of a cholinergic pathway.