Cortical expression of prolactin (PRL), growth hormone (GH) and adrenocorticotrophic hormone (ACTH) is not increased in experimental traumatic brain injury.

BACKGROUND: Cerebral cortical expression of the pituitary hormones prolactin (PRL) and growth hormone (GH) have reported in ischemic damage. Both hormones may be involved in vascular tone regulation and angiogenesis, and growth hormone is thought to be neuroprotective while prolactin stimulates astrogliosis. METHODS: We examined expression of prolactin, growth hormone and adrenocorticotrophic hormone (ACTH) using tissue microarray technology in the controlled cortical impact model of traumatic brain injury (TBI). FINDINGS: No increased expression of these hormones was seen. CONCLUSIONS: Unlike ischemia, traumatic brain injury does not result in up-regulation of the pituitary hormones PRL and GH in cerebral cortex.

Pro-inflammatory and pro-apoptotic elements of the neuroinflammatory response are activated in traumatic brain injury.

BACKGROUND: The inflammatory response may contribute to cerebral edema, increased intracranial pressure and cellular loss in traumatic brain injury (TBI). Cytokines are biomarkers of this inflammatory response and new methods allow simultaneous measurement of multiple cytokines. METHODS: We examined the IL-1beta, IL-6, IL-8 and IL-12, TNFalpha, and IL-10 in arterial and jugular blood as well as cerebrospinal fluid in patients with severe traumatic brain injury. FINDINGS: Multiple cytokines, particularly pro-inflammatory cytokines, are up-regulated following TBI. Cerebrospinal fluid and arteriovenous differences of some of the cytokines suggest production within the central nervous system. Antiinflammatory cytokines are not up-regulated. CONCLUSIONS: Cytokine up-regulation may contribute to the neuroinflammatory reaction that follows traumatic brain injury and may contribute to secondary injury.

Cerebral phaeohyphomycosis caused by ladophialophora bantiana and Fonsecaea monophora: report of three cases.

Three cases of cerebral phaeohyphomycosis are described. Two cases (Cases 1, 2) are caused by highly neurotropic fungi, Cladophialophora bantiana, and the other one (Case 3) is the first reported case in the United States, caused by the newly defined Fonsecaea monophora. (Case 1): A 65-year-old woman had been treated for a presumed diagnosis of Guillain-Barré syndrome and was found to have a ring-enhancing, fluid-filled lesion in the right frontal lobe. The lesion was aspirated twice and then resected completely. (Case 2): A 45-year-old woman with a history of severe dermatomyositis presented with subacute ischemia in the left brainstem. Approximately 2 months later, she developed acute obstructive hydrocephalus and was found to have small cystic lesions in the left ambient cistern, fourth ventricle and cerebral aqueduct, which had probably caused the previous ischemic symptoms due to emboli/ thrombi. (Case 3): A 62-year-old, post livertransplant woman developed multiple brain and bone abscesses. Cultures from these lesions grew the same fungi. Histologically, all three cases revealed multiple epithelioid and giant cell granulomata with groups of golden-brown yeast-like cells as well as chains of budding cells. In Case 3, scattered muriform cells, characteristic of chromoblastomycosis, were present. In Cases 2 and 3, the fungi were easily identified on frozen sections, which may be considered useful in determining post-operative therapy.

Adenovirus-mediated gene therapy in an experimental model of breast cancer metastatic to the brain.

We investigated the therapeutic efficacy of adenovirus-mediated gene therapy to treat malignant mammary tumors in vitro and in vivo in the brain. A mammary adenocarcinoma cell line derived from Fischer rats (13762 MAT B III; MAT-B) was used. In vitro studies demonstrated that the MAT-B cells could be efficiently transduced with a replication-defective adenovirus (ADV) vector that carried the herpes simplex virus gene for thymidine kinase (ADV-tk), and that ADV-tk transduction rendered the MAT-B cells sensitive to killing, in a dose-dependent manner, with ganciclovir (GCV). An animal model of a mammary tumor metastatic to the brain was produced by injecting MAT-B cells into the caudate nucleus of Fischer rats. Seven days after MAT-B cell injection, when the tumors were approximately 5 mm2 in cross-sectional size, the tumors were injected with ADV-tk or a control adenovirus vector containing the beta-galactosidase (beta-Gal) gene (ADV-beta gal). After vector injection the animals were treated with GCV or with saline for 6 days. Sixteen days after tumor cell injection, the brains were examined histologically. The rats that were injected with ADV-beta gal and treated with GCV or saline, and those that were injected with ADV-tk and treated with saline had large tumors, whereas the rats that were injected with ADV-tk and treated with GCV had no visible tumor tissue at the site of tumor cell injection. In survival studies animals treated with ADV-tk+GCV survived a significantly longer time than animals treated with ADV-beta gal+GCV. Our results demonstrate that the recombinant adenoviral vector containing the tk gene confers GCV cytotoxic sensitivity to mammary tumor cells in vitro and in the brain, and suggest that this treatment strategy may be useful in treating somatic tumors that metastasize to the brain.

Adenoviral-mediated thymidine kinase gene transfer into the primate brain followed by systemic ganciclovir: pathologic, radiologic, and molecular studies.

Transduction of experimental gliomas with the herpes simplex virus thymidine kinase gene (HSV-tk) using a replication-defective adenoviral vector (ADV/RSV-tk) confers sensitivity to ganciclovir (GCV) leading to tumor destruction and prolonged host survival in rodents. To determine treatment tolerance prior to clinical trials, we conducted toxicity studies in 6 adult baboons (Papio sp.). The animals received intracerebral injections of either a high dose of ADV/RSV-tk [1.5 x 10(9) plaque-forming units (pfu)] with or without GCV, or a low dose of ADV/RSV-tk (7.5 x 10(7) pfu) with GCV. The low dose corresponded to the anticipated therapeutic dose; the high dose was expected to be toxic. Magnetic resonance imaging (MRI) of the brain was obtained before treatment and at 3 and 6 weeks after treatment. Animals receiving the high-dose vector and GCV either died or became moribund and required euthanasia during the first 8 days of treatment. Necropsies revealed cavities of coagulative necrosis at the injection sites. Animals receiving only the high-dose vector were clinically normal; however, lesions were detected with MRI at the injection sites corresponding to cystic cavities at necropsy. Animals receiving the low-dose vector and GCV were clinically normal, exhibited small MRI abnormalities, and, although no gross lesions were present at necropsy, microscopic foci of necrosis were present. The vector sequence was detected by polymerase chain reaction (PCR) at the injection sites and in non-adjacent central nervous system tissue in all animals. Recombinant DNA sequence was detected outside of the nervous system in some animals, and persisted up to 6 weeks. The viral vector injections stimulated the production of neutralizing antibodies in the animals. No shedding of the vector was found in urine, feces, or serum 7 days after intracerebral injection. This study suggests that further investigations including clinical toxicity trials of this form of brain tumor therapy are warranted.

DFMO reduces cortical infarct volume after middle cerebral artery occlusion in the rat.

Ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis, is induced in ischemic tissue and may mediate vasogenic edema and delayed neuronal death. We determined the effects of alpha-difluoromethylornithine (DFMO), a specific inhibitor of ODC, on infarct size and ODC activity in a rat model of transient focal ischemia. DFMO blocked the ischemia-induced increase in ODC and significantly reduced infarct volumes by 57-45%, depending upon the treatment regimen. These studies suggest that polyamine metabolism plays a role in the development of cerebral infarction after focal ischemia and that DFMO may be useful in limiting injury after a stroke.

Acute subdural hematoma and metastatic seminoma.

Acute and chronic nontraumatic subdural hematomas are rare complications of dural metastases from disseminated malignant neoplasms. We found an acute subdural hematoma in a patient with testicular seminoma metastatic to the dura.

Unilateral asterixis: motor integrative dysfunction in focal vascular disease.

In three patients we found unilateral asterixis in limbs contralateral to a discrete lesion adjacent to the internal capsule. Etiology was vascular in each, with no metabolic or toxic disturbance. Unilateral asterixis bespeaks focal disease arising from lesions in the thalamus or internal capsule and is a sign of motor integrative dysfunction.

Increased CSF glutamate following injection of ALS immunoglobulins.

To reconcile the autoimmune and excitotoxic hypotheses regarding the etiology of amyotrophic lateral sclerosis (ALS), we injected rats intraperitoneally with ALS immunoglobulins and monitored CSF glutamate, aspartate, glutamine, and glutathione. CSF glutamate was significantly increased at 24 and 72 hours compared with both basal levels and disease control injected rats. CSF aspartate was increased at 72 hours. Glutamine and glutathione were unchanged. These data suggest that ALS immunoglobulins may enhance CSF glutamate and aspartate levels and contribute to motoneuron injury.

Elevation of tumor necrosis factor in head injury.

Tumor necrosis factor (TNF) is a cytokine which mediates protein wasting in pathological states by promoting the catabolism of visceral tissues and skeletal muscle. The role that TNF plays in nitrogen wasting following head injury was studied by measuring TNF in the serum of 21 patients with severe head injury. Parallel measurements of TNF and urinary nitrogen excretion were performed on days 1, 3, and 5 after head injury. TNF values after head injury ranged from 65 pg/ml to 7500 pg/ml, with a mean of 1147 pg/ml, compared to control values of serum TNF of less than 38 pg/ml. The mean daily urinary nitrogen loss was 13 g/day with a range of 2.8 to 27.6 g/day, and the mean nitrogen balance was -5.8 g with a range of +4.6 to -19.1 g. While both serum TNF levels and nitrogen loss were increased after head injury, the elevation of TNF did not correlate strongly with nitrogen wasting.

Secondary insults increase injury after controlled cortical impact in rats.

Secondary ischemic insults are common after severe head injury and contribute to poor neurological outcome. To study the increased vulnerability of the traumatized brain to secondary insults, bilateral carotid occlusion was produced after a controlled cortical impact injury in rats. The injury produced by either the impact injury or the bilateral carotid occlusion was mild to moderate when studied individually. The 1 and 3 m/sec impact injuries alone caused no detectable contusion at the impact side and minimal neuronal loss in the hippocampus. The 5 m/sec impact injury alone resulted in a small contusion with a median volume of 5.4 mm3. The 40-min period of bilateral carotid occlusion alone caused no cortical injury and no neuronal loss in the CA1 region of the hippocampus. When the 40 min of bilateral carotid occlusion was produced 1 h after the impact injury, there was an increase in the damage produced. The contusion volume was significantly larger after the 3 and 5 m/sec impact injuries and the hippocampal neuronal loss was significantly greater after the 1 and 3 m/sec impact injuries. When varying durations of bilateral carotid occlusion were produced 1 h after a 3 m/sec impact injury, contusion volume was significantly larger after bilateral carotid occlusion duration of 40 min, and CA1 neuronal loss was significantly greater after bilateral carotid occlusion durations of 30 and 40 min. When 40 min of bilateral carotid occlusion was produced at different time intervals after a 3 m/sec injury, the increased contusion volume was maximal when bilateral carotid occlusion occurred at 4 h after the impact injury, and the increased neuronal loss in the CA3 region of the hippocampus was maximal when bilateral carotid occlusion occurred at 1 h after the impact injury. By 24 h after the impact injury, 40 min of bilateral carotid occlusion had minimal consequences, similar to the effect in sham-injured animals. These results mimic the clinical situation where secondary insults of a severity that would not cause permanent neurological damage in a normal person are associated with a marked worsening of neurological outcome after head injury and where the injured brain is most susceptible to secondary insults in the first few hours after injury.

Effect of glucose administration on contusion volume after moderate cortical impact injury in rats.

Previous studies had shown that pre- and postinjury glucose administration increased brain injury caused by a mild cortical impact injury only when the traumatic injury was complicated by a secondary ischemic insult. The purpose of this study was to examine the effect of pre- and postinjury glucose administration on a more severe cortical impact injury, where primary ischemia occurs at the site of the impact. Long Evans rats who were fasted overnight and anesthetized with isoflurane were subjected to a 5-m/sec, 2.5-mm impact injury. The animals were randomly assigned one of the following treatments: (1) 2.2 g/kg glucose in 4 ml of saline, 20 min prior to injury; (2) 2.0 g/kg glucose in 4 ml of saline, 20 min after injury; or (3) 4 ml of saline either 20 min before injury or 20 min after the injury. At 2 weeks, the animals were sacrificed and the brains were examined for contusion volume and for neuronal loss in CA1 and CA3 regions of the hippocampus. Contusion volume was increased from a median value of 23 mm3 in the saline-infused animals to 34 mm3 in the preimpact glucose infusion animals (p=0.005). Postimpact glucose infusion had no effect on contusion volume. Neuron density in CA1 and CA3 regions of the hippocampus was similar in all three treatment groups. These studies support the hypothesis that glucose administration adversely affects experimental traumatic brain injury in those circumstances where the trauma is complicated by primary cerebral ischemia, such as around cortical contusions.

Blood flow and metabolic therapy in CNS injury.

A hypermetabolic state, consisting of increased resting energy expenditure, excessive protein wasting, and hyperglycemia, occurs in patients with a severe head injury. The hypermetabolism can affect survival by rapidly resulting in protein-calorie malnutrition (increased energy expenditure and protein wasting) and may adversely affect neurological recovery by altering the microenvironment of the injured brain (hyperglycemia).

Lateral cortical impact injury in rats: pathologic effects of varying cortical compression and impact velocity.

Direct lateral cortical impact through the intact leptomeninges using a pneumatically driven piston produces increasingly severe pathophysiologic derangements with increasing cortical deformation. We studied the histopathologic correlates of cortical impact injury produced by 2 mm, 2.5 mm, and 3 mm deformation in the rat at 5 m/sec. Additionally, the effect of impact velocity at a 2.5 mm deformation was assessed at 1 m/sec, 3 m/sec, and 5 m/sec. The brains were examined 14 days after injury. Cortical contusion maximum cross-sectional area, volume, and the percentage CA1 and CA3 hippocampal neuronal loss correlate with cortical deformation and impactor velocity. Contusion volume increased with increasing cortical deformation. Deformations of 2, 2.5, and 3 mm at 5 m/sec produced contusion volumes of 4.59, 8.9, and 21.68 mm3, respectively. At a fixed cortical deformation of 2.5 mm, contusion volume increased with increasing impact velocity. Impact velocities of 1, 3, and 5 m/sec produced contusion volumes of 5.79, 7.42, and 8.9 mm3, respectively. Hippocampal CA3 neuronal loss increased with increasing cortical deformation. Deformations of 2, 2.5, and 3 mm at 5 m/sec produced neuronal loss of 29%, 48.3%, and 79.5%, respectively. At a fixed cortical deformation of 2.5 mm, hippocampal CA3 neuronal loss increased with increasing impact velocity. Impact velocities of 1, 3, and 5 m/sec produced neuronal loss of 18.25%, 33.75%, and 48.3%, respectively. Hippocampal CA1 neuronal loss was also seen and paralleled cortical deformation and impact velocity. Cortical deformation and impact velocity are critical parameters in producing cortical contusion and must be considered when comparing results using this model.

Reduction in spinal cord postischemic lactic acidosis and functional improvement with dichloroacetate.

Pyruvate dehydrogenase complex (PDHC) is a major enzyme of glucose metabolism. Dichloroacetate (DCA) is a noncompetitive inhibitor of PDHC kinase, an enzyme that inactivates PDHC. We examined the effects of DCA on extracellular lactate and pyruvate concentration changes and spinal somatosensory evoked potentials (SSEP) in ischemic rabbit spinal cords. In the first group of 26 animals, the aorta was occluded until postsynaptic SSEP waves were completely suppressed for 10 min, a period of ischemia that causes neurologic deficits in 50% of untreated animals. DCA (25 mg/kg) was given to 13 of these animals before ischemia. In the second group of 24 animals, the aorta was occluded until the postsynaptic SSEP waves were absent for 20 min, a period of ischemia that produces paraplegia in 100% of untreated animals. DCA (25 mg/kg) was given to 16 of these animals just before the aortic occlusion was released. After occlusion, extracellular spinal lactate concentrations increased abruptly while pyruvate concentrations fell. Both lactate and pyruvate concentrations reached a plateau during the ischemic period but increased when the aortic balloon was deflated. DCA-treated animals had lower lactate and pyruvate peak concentrations during reperfusion, as well as more rapid and greater recovery of SSEP at 2 h after reperfusion. DCA did not alter spinal metabolism during the ischemia but appeared to produce a more rapid shift to glucose metabolism on reperfusion. Thus, DCA treatment resulted in better electrophysiological recovery after both moderate and severe ischemia, either by reducing lactic acidosis or by increasing the recovery rate of aerobic energy production.

Evaluation of a carbohydrate-free diet for patients with severe head injury.

Hyperglycemia, which may be caused or exacerbated by conventional diets, may worsen the neurological outcome from severe head injury, especially if secondary ischemic insults occur. The purpose of this study was to evaluate an experimental diet intended to replace systemic caloric and protein requirements without producing hyperglycemia. In initial studies in the laboratory, 5 experimental diets were employed in a middle cerebral artery temporary occlusion model. The effects of the diets on blood biochemistry and on infarction volume were compared in fasted animals and in animals fed a control diet. Animals fed the experimental diets had a significantly lower preischemia blood glucose concentration, a higher blood concentration of ketone bodies, and a smaller infarct volume than the animals fed a control diet. One diet chosen from the laboratory study was then evaluated in a clinical study as a randomized, open-label trial. Twenty severely head-injured patients were randomly assigned to be fed the experimental diet, EN-9305, or the control diet, Osmolyte HN, for the first 2 weeks after injury. Both treatment groups had similar blood glucose concentrations, averaging 6.33 +/- 0.21 mumol/mL (114 +/- 4 mg/dL), on day 1 prior to starting the assigned diet. Blood glucose concentration increased in the control diet group to a peak of 8.37 +/- 0.94 mumol/mL (151 +/- 17 mg/dL) on day 7 as the infusion rate of the diet was increased to the final rate. In the experimental diet group, the blood glucose concentration remained unchanged from fasting levels as the diet was advanced. Blood lactate concentration was lower, and blood ketone body concentrations were higher in the patients fed the experimental diet. Urinary nitrogen balance was better in the experimental diet group, but measures of visceral protein sparing, including serum albumin, plasma retinol binding protein, and total lymphocyte count, were not significantly different in the 2 treatment groups. Measures of cerebral anaerobic metabolism, including CSF lactate concentration and cerebral lactate production, were not significantly different in the 2 treatment groups. These studies suggest that a carbohydrate-free diet such as EN-9305 might have advantages for patients with severe head injury by replacing systemic caloric and protein requirements without producing hyperglycemia.

Lactate and excitatory amino acids measured by microdialysis are decreased by pentobarbital coma in head-injured patients.

Primary traumatic brain injury and secondary ischemic/hypoxic injury are being increasingly characterized at the neurochemical level. Neurochemical monitoring using microdialysis has shown that these forms of tissue damage share many common features. In particular, anaerobic glycolysis with increased lactate production and release of excitatory amino acids into the extracellular space are seen in both conditions. Clinical microdialysis studies have heretofore focused on methodological issues, establishment of basal analyte values, and clinico-neurochemical correlation. Here we report the neurochemical consequences of therapeutic intervention in head injury. Specifically, induction of thiopental coma to manage severe increased intracranial pressure in seven patients was associated with a 37% reduction of lactate, 59% reduction of glutamate, and 66% reduction in aspartate in the extracellular space of the brain.

Hyperglycemia increases neurological damage and behavioral deficits from post-traumatic secondary ischemic insults.

The effects of post-traumatic administration of glucose 2.0 g/kg was compared to saline infusion with and without control of brain temperature at 37 degrees C on behavioral and histological measures of brain injury after controlled cortical impact injury complicated by a secondary ischemic insult. The glucose infusion increased blood glucose concentration from 114 +/- 4 to 341 +/- 76 mg/dl prior to the secondary ischemic insult. The resulting outcome measures were significantly worse in the glucose infusion group than in either control group. Mortality rate was significantly increased by the glucose administration, from 0% to 55% (p < 0.001). The median contusion volume was increased from 7.9 to 64.2 by glucose administration (p < 0.001) and the neuronal loss in the CA1 and CA3 areas of the hippocampus were greater in the glucose infusion group. In the animals that survived for the 2 weeks of behavioral studies, the duration of beam balance was shorter; the percent of animals that could balance on the beam for at least 60 s was less, the percent of animals that could perform the beam-walking task was less, and the length of time required to find the platform in the Morris water maze task was longer in the glucose infusion group. These studies demonstrate that the infusion of glucose after the cortical impact injury significantly increases the damage caused by post-traumatic ischemic insults. The adverse effect on neurological outcome could not be explained by the temperature effects of glucose infusion.

Comparison of brain tissue oxygen tension to microdialysis-based measures of cerebral ischemia in fatally head-injured humans.

This study investigated the relationship between brain tissue oxygen tension (PbtO2) and cerebral microdialysate concentrations of several compounds in five patients with refractory intracranial hypertension after severe head injury. The following substances were assayed: lactate and glucose; the excitatory amino acids glutamate and aspartate; and the cations potassium, calcium, and magnesium. Glucose concentrations did not correlate with PbtO2, but lactate increased as PbtO2 decreased. The lactate/glucose ratio exhibited a close relationship to PbtO2, increasing sharply only when oxygen tension reached zero. Although glucose and oxygen eventually reached very low levels and zero, respectively, in these fatally head-injured patients, the terminal decrease in PbtO2 slightly preceded that of glucose in four of the five patients. This time lag is the cause of the poor correlation between glucose and PbtO2. Glutamate and aspartate concentrations both demonstrated a close relationship to PbtO2, with sharp increases not occurring until PbtO2 was zero. Concentrations of these amino acids exhibited a similar pattern in response to decreasing glucose concentrations. Potassium concentrations began increasing at a PbtO2 of 35 mm Hg, which is not generally considered indicative of hypoxia. Sharper increases began occurring once PbtO2 dropped below 15 mm Hg, with a slight rise in the minimum potassium concentrations recorded at these low PbtO2 values. Calcium and magnesium concentrations did not vary in response to PbtO2. In summary, the most robust biochemical indicators of cerebral anoxia were elevations in the lactate/glucose ratio and in the concentrations of lactate and of the excitatory amino acids glutamate and aspartate. Furthermore, the fact that glucose concentrations continue to decrease for a short period after oxygen levels reach zero suggests that cells continue to utilize glucose anaerobically for such functions as maintenance of cellular integrity, with collapse of the cell membrane as evidenced by increases of extracellular glutamate and aspartate not occurring until both oxygen and glucose concentrations reach zero.