Characterization and Deactivation Study of Mixed Vanadium and Potassium Oxide Supported on Microemulsion-Mediated Titania Nanoparticles as Catalyst in Oxidative Dehydrogenation of Propane

The influence of potassium addition to the vanadia supported on the microemulsion-mediated TiO2 nanoparticles in propane oxidative dehydrogenation was studied. Raman spectroscopy demonstrated that the addition of potassium caused enhanced dispersion of vanadia species on the support surface. Also, potassium existence affects the H2 temperature programmed reduction maximum reduction temperature and shifted it to 520°C, which was in accordance with its lesser catalytic activity. Nevertheless, a propylene selectivity enhancement was observed by potassium addition. In spite of the fact that the catalytic performance loss was not severe in vanadia-supported TiO2 anatase, potassium addition led to improve the catalyst lifetime. After deactivation test, potassium-containing vanadia catalyst possessed lower surface area loss (i.e. from 52 to 49 m2 g−1). Average crystallite size of potassium-containing vanadia catalyst exhibited lower decrease than that of potassium-free vanadia catalyst after deactivation test. According to Raman spectra, deactivation phenomena had influenced the population of vanadia species so that monovanadates decreased and polyvanadates increased.

Effect of extreme hypercapnia on hypoxic-ischemic brain damage in the immature rat

To ascertain the effect of extreme hypercapnia on perinatal hypoxic-ischemic brain damage, 7-d-postnatal rats were exposed to unilateral common carotid artery occlusion followed by hypoxia with 8% oxygen combined with 3, 12, or 15% carbon dioxide (CO2) for 2 h at 37 degrees C. Survivors underwent neuropathologic examination at 30 d of postnatal age, and their brains were characterized as follows: 0 = normal; 1 = mild atrophy; 2 = moderate atrophy; 3 = cystic infarct with external dimensions <3 mm; and 4 = cystic infarct with external dimensions >3 mm. The width of the cerebral hemisphere ipsilateral to the carotid artery occlusion also was determined on a posterior coronal section and compared with that of the contralateral hemisphere to ascertain the severity of cerebral atrophy/cavitation. CO2 tensions averaged 5.08, 11.1, and 13.2 kPa in the 3, 12, and 15% CO2-exposed animals, respectively, during hypoxia-ischemia (HI). Neuropathologic results showed that immature rats exposed to 3 and 12% CO2 had similar severities of brain damage. In contrast, rat pups exposed to HI combined with 15% CO2 were significantly more brain damaged than littermates exposed to 3% CO2. Specifically, eight of 14 animals exposed to 15% CO2 showed cystic infarcts (grades 3 and 4), whereas none of 14 littermates exposed to 3% CO2 developed cystic infarcts (p < 0.01). Analyses of coronal width ratios at each CO2 exposure provided results comparable with those of the gross neuropathology scores. Cerebral blood flow (CBF), measured at 90 min of HI, was lowest in those immature rats exposed to 15% CO2 compared with control (p = 0.04), with higher values in those rat pups exposed to 3 and 12% CO2. The findings indicate that 7-d-postnatal rats exposed to HI with superimposed 12% CO2 are neither less nor more brain damaged than littermates exposed to 3% CO(2) (normocapnia). In contrast, animals exposed to 15% CO2 are the most brain damaged of the three groups. Presumably, extreme hypercapnia produces more severe cardiovascular depression than is seen in animals subjected to lesser degrees of hypercapnia; the cardiovascular depression, in turn, leads to greater cerebral ischemia and ultimate brain damage.

Primitive neuroectodermal tumor of cerebrum with adipose tissue

Primitive neuroectodermal tumors (PNETs) of the central nervous system are uncommon embryonal neoplasms, rarely occurring in adults. Differentiation into specific mesenchymal tissues, such as cartilage, bone, skeletal muscle, smooth muscle, or adipose tissue, is rare. We report a case of a 51-year-old woman with a PNET of cerebrum that showed extensive mature adipose tissue differentiation. This is the second case, to our knowledge, of PNET of cerebrum with adipose tissue elements that has been described.

Experimental stroke in the female diabetic, db/db, mouse

Diabetic hyperglycemia increases brain damage after cerebral ischemia in animals and humans, although the underlying mechanisms remain unclear. Gender-linked differences in ischemic tolerance have been described but have not been studied in the context of diabetes. In the current study, we used a model of unilateral common carotid artery ligation, combined with systemic hypoxia, to study the effects of diabetes and gender on hypoxic-ischemic (HI) brain damage in the genetic model of Type II diabetes, the db/db, mouse. Male and female, control and db/db, mice were subjected to right common carotid artery ligation followed by varying periods of hypoxia (8% oxygen/92% nitrogen) to assess mortality, infarct volume, and tissue damage by light microscopic techniques. End-ischemic regional cerebral blood flow (CBF) was determined using [14C] iodoantipyrine autoradiography. Glycolytic and high energy phosphate compounds were measured in blood and brain by enzymatic and fluorometric techniques. Gender and diabetes had significant effects on mortality from HI and extent of brain damage in the survivors. Female mice were more resistant than their male counterparts, such that the severity (mortality and infarction size) in the male diabetics > female diabetics - male controls > female controls. Endischemic CBF and depletion of cerebral high energy reserves were comparable among all groups. Surprisingly, female diabetic mice were more hyperglycemic and demonstrated a greater prolonged lactacidosis than the males; however, they were more resistant to damage. The results suggest a unique pathophysiology of hypoxia-ischemia in the female diabetic brain.

Increased plasma beta-hydroxybutyrate, preserved cerebral energy metabolism, and amelioration of brain damage during neonatal hypoxia ischemia with dexamethasone pretreatment

Dexamethasone (DEX) pretreatment has been shown to be neuroprotective in a neonatal rat model of hypoxia ischemia (HI). The exact mechanism of this neuroprotection is still unknown. This study used 31P nuclear magnetic resonance spectroscopy to monitor energy metabolism during a 3-h episode of HI in 7-d-old rat pups in one of two groups. The first group was pretreated with 0.1 mL saline (i.p.) and the second group was treated with 0.1 mL of 0.1mg/kg DEX (i.p.) 22 h before HI. Animals pretreated with DEX had elevated nucleoside triphosphate and phosphocreatine levels during HI when compared with controls. Saline-treated animals had significant decreases in nucleoside triphosphate and phosphocreatine and increases in inorganic phosphate over this same period. 31P nuclear magnetic resonance data unequivocally demonstrate preservation of energy metabolism during HI in neonatal rats pretreated with DEX. Animals pretreated with DEX had little or no brain damage following 3 h of HI when compared with matched controls, which experienced severe neuronal loss and cortical infarction. These same pretreated animals had an increase in blood beta-hydroxybutyrate levels before ischemia, suggesting an increase in ketone bodies, which is the neonate's primary energy source. Elevation of ketone bodies appears to be one of the mechanisms by which DEX pretreatment provides neuroprotection during HI in the neonatal rat.

Optic nerve enlargement in Krabbe's disease

We report imaging and gross pathologic findings from two cases of Krabbe disease in which there was marked enlargement of the intracranial optic nerves. Numerous globoid cells were observed in the optic nerves at autopsy in one case. Krabbe disease should be included in the differential diagnosis of children with enlargement of the optic nerves.

Effect of seizures on cerebral hypoxic-ischemic lesions in immature rats

The present investigation was designed to study the effect of chemically induced seizures on cerebral hypoxic-ischemic (HI) damage in immature animals. Accordingly, cerebral HI was produced in 7-day postnatal (p7) rats and p13 rats by combined unilateral common carotid artery ligation and hypoxia with 8% oxygen. Seizures were induced chemically by the subcutaneous injection of kainic acid (KA) or inhalation of flurothyl vapor. Three types of experiments were conducted in each age group and for each convulsant. In some animals (group 1), seizures were produced at 24 h and again at 6 h prior to HI. In groups 2 and 3, seizures were induced 2 h or 24 h post HI, respectively. The results indicate that in group 1 animals, the first seizure significantly reduced duration of the second seizure challenge 18 h later at both p7 and p13 (p=0.001). Histologic examination of brains of animals in group 1 subjected to seizures prior to HI and their HI-only controls showed that seizures prior to HI conferred protection against cerebral damage. This effect was significant for flurothyl seizures in p13 rats for all cerebral regions, especially hippocampal CA1 (p=0.0004), and in p7 rats for hippocampus (p=0.04) and particularly cerebral cortex (p=0.007). For KA seizures, the protective effect was only significant in p13 rats and was limited to hippocampal CA regions and subiculum (p=0.0009). Histologic assessment of cerebral lesions of p7 and p13 rats in the other two groups showed no significant difference between the animals subjected to seizures 2 h or 24 h post HI and their HI-only controls (p>0.05). In conclusion, the results of the present study provide no evidence that seizures in early postnatal development aggravate pre-existing cerebral HI damage. They do suggest that seizures prior to HI or prior to a second seizure confer tolerance to both conditions.

Experimental models of hypothermic circulatory arrest

This article reviews information obtained from experimental models of hypothermic circulatory arrest, which models have been developed in our and other laboratories over the past several years. The described experiments clearly demonstrate an ability to produce and completely reverse hypothermic circulatory arrest in newborn and developing animals, allowing for a comprehensive evaluation of those physiological variables and therapeutic interventions that would potentially reduce or accentuate ischemic brain damage. Further experiments will allow for a determination of whether or not specific modalities of therapy will reverse secondary systemic complications, thereby allowing for more complete recoverability and ultimately reduced brain damage.

Rat model of perinatal hypoxic-ischemic brain damage

To gain insights into the pathogenesis and management of perinatal hypoxic-ischemic brain damage, the authors have used an immature rat model which they developed many years ago. The model entails ligation of one common carotid artery followed thereafter by systemic hypoxia. The insult produces permanent hypoxic-ischemic brain damage limited to the cerebral hemisphere ipsilateral to the carotid artery occlusion. The mini-review describes recently accomplished research pertaining to the use of the immature rat model, specifically, investigations involving energy metabolism, glucose transporter proteins, free radical injury, and seizures superimposed upon cerebral hypoxia-ischemia. Future research will focus on molecular mechanisms of neuronal injury with a continuing focus on therapeutic strategies to prevent or minimize hypoxic-ischemic brain damage.

Localized hypertrophic neuropathy: magnetic resonance imaging findings and long-term follow-up

Four patients with painless, progressive focal neurological deficits that localized to peripheral nerve or plexus were eventually found to have the relatively rare condition of localized hypertrophic neuropathy or intraneural perineurioma. Magnetic resonance imaging (MRI) was an excellent tool for aiding in the precise localization of the lesion, if specifically tailored with regard to imaging planes and specific MRI sequences. Fat-saturated T2-weighted and fat-saturated T1-weighted postgadolinium images provided the best visualization, particularly with a high-field magnet and phase array body coil. Two patients stabilized following resection of the lesion and sural nerve grafting, and 1 had partial improvement in a proximal muscle following neurolysis.

Hypoxic preconditioning and hypoxic-ischemic brain damage in the immature rat: pathologic and metabolic correlates

It has been reported that immature rats subjected to cerebral hypoxia-ischemia sustain less brain damage if they are previously exposed to systemic hypoxia compared with animals not exposed to prior hypoxia. Accordingly, neuropathologic and metabolic experiments were conducted to confirm and extend the observation that hypoxic preconditioning protects the perinatal brain from subsequent hypoxic-ischemic brain damage. Six-day postnatal rats were subjected to systemic hypoxia with 8% oxygen at 37 degrees C for 2.5 h. Twenty-four hours later, they were exposed to unilateral cerebral hypoxia-ischemia for 2.5 h, produced by unilateral common carotid artery ligation and systemic hypoxia with 8% oxygen. Neuropathologic analysis, conducted at 30 days of postnatal age, indicated a substantial reduction in the severity of brain damage in the preconditioned rats, such that only 6 of 14 such animals exhibited cystic infarction, but all 13 animals without prior preconditioning exhibited infarction (p < 0.001). Measurement of cerebral glycolytic and tricarboxylic acid intermediates and high-energy phosphate reserves at the terminus of and at 4 and 24 h following hypoxia-ischemia showed no differences in the extent of alterations in the preconditioned and nonpreconditioned immature rats. A difference was seen in the restitution of high-energy stores during the first 24 h of recovery from hypoxia-ischemia, with a more optimal preservation of these metabolites in the preconditioned animals, reflecting the less severe ultimate brain damage. Accordingly, the neuroprotection afforded to the preconditioned animals was not the result of any differences in the extent of anaerobic glycolysis, tissue acidosis, or depletion in high-energy reserves during hypoxia-ischemia but rather the result of other mechanisms that improved the metabolic status of the immature brain during the early hours of reperfusion following hypoxia-ischemia.

Temporal evolution of neuronal changes in cerebral hypoxia-ischemia in developing rats: a quantitative light microscopic study

Studies in adult animal models of transient cerebral hypoxia-ischemia (HI) and ischemia suggest that morphologic evidence of neuronal death in some regions such as striatum appears early, while in other regions such as cerebral cortex and CA1 region of hippocampus it is delayed for few days and is referred to as delayed neuronal death (DND). Moreover, in some regions such as CA2/CA3 early 'reactive' neuronal changes occur that are potentially reversible. The aim of this study was to determine whether such changes may also occur in the developing brain. To that end, unilateral cerebral HI was produced in postnatal rats of 13, 21, and 30 days (p13, p21, p30) by right common carotid artery ligation and hypoxemia (breathing 8% O2), and their brains were examined at 24 h, 36 h, 72 h, and 96 h of recovery. The results suggest that: (i) DND is present in developing brain, but its regional distribution varies with animals' age. In cerebral cortex, it is more pronounced in p30 rats than in younger animals. In hippocampus, comparison of lesions of similar severity at different age groups shows a more pronounced DND in CA2/CA3 region of p13 rats than in older animals, but no significant differences exist in the degree of DND in CA1 neurons among different age groups. (ii) 'Reactive' neuronal changes characterized by reduction in Nissl staining and acidophilia of neuronal perikaryon with minimal nuclear abnormality are present at 24 h of recovery. These changes in some regions, such as in CA1 and cortex, progress to neuronal death, while in other regions such as in CA2/CA3 are potentially reversible. (iii) Recovery of reactive neurons in CA2/CA3 region is age dependent in that there is significant recovery in the older age groups, but not in p13 rats. The pathogenetic mechanisms of the reactive neuronal changes, the chain of events leading to DND or neuronal recovery, and the influence of age in these processes remain to be elucidated.

Measuring the accentuation of the brain damage that arises from perinatal cerebral hypoxia-ischemia

To ascertain the manner in which the severity of perinatal brain damage occurs as a result of hypoxia-ischemia, 7-day postnatal rats were subjected to unilateral common carotid artery ligation followed thereafter by exposure to 8% oxygen for up to 2.5 h. Following the hypoxic-ischemic exposure, the rat pups were reared with their dams until 30 days of postnatal age, at which time their brains underwent pathologic analysis. The severity of brain damage at each of four specific intervals of hypoxia-ischemia was determined and statistically compared by linear polynomial and nonparametric regression procedures. The data indicated that the accentuation of brain damage with increasing duration of hypoxia-ischemia was linear rather than curvilinear.

Influence of age on the cerebral lesions in an immature rat model of cerebral hypoxia-ischemia: a light microscopic study

The most frequently used model of neonatal cerebral hypoxia-ischemia consists of a 7-day postnatal rat model with combined common carotid artery ligation and hypoxemia. Neuropathologic studies have shown major differences between this 7-day postnatal rat model and a similar adult model in regard to overall cerebral vulnerability, type and distribution of lesions. It is not clear how and when during animals' development these changes in cerebral vulnerability take place. To determine this we studied groups of rats of 2 to 30 postnatal days. The animals underwent unilateral common carotid artery ligation followed by breathing in 8% oxygen for 30, 60, 90, or 120 min and their brains were examined at 24- or 72-h recovery intervals. Due to resistance of 2-3-day-old rats to develop cerebral hypoxic-ischemic damage, 5% O2 was used instead of 8% O2. The results indicate that: (i) There is an overall increase in severity of cerebral lesions on the side of common carotid artery ligation between 2 and 7 postnatal days. There is also an increase in the frequency of cerebral lesions in developing animals with increasing age. (ii) Hippocampus is remarkably resistant to hypoxic-ischemic insult at 2-3 postnatal days but becomes progressively vulnerable, and by age 13 postnatal days hippocampal vulnerability far exceeds that of cortex. (iii) Cortical lesions change from predominantly columnar cell death to laminar selective neuronal death at age 13 postnatal days. (iv) Also significant changes occur in relative vulnerability of various hippocampal regions during development. During the first 5 postnatal days relative vulnerability of hippocampal regions is similar, but as the animals' development proceeds and hippocampal vulnerability increases lesions tend to involve specific regions while sparing others. By age 13 postnatal days CA1 and lateral CA3 develop increased vulnerability while medial CA3 and fascia dentata become relatively resistant and by 21 postnatal days adult pattern of CA1 selective vulnerability is approached. The underlying mechanisms for these changes in regional vulnerability to cerebral hypoxia-ischemia during development should be sought in complex regional anatomic, functional, and metabolic alterations that take place as brain matures.

The role of neutrophils in the production of hypoxic-ischemic brain injury in the neonatal rat

Neutrophils contribute to ischemic brain injury in adult animals. The role of neutrophils in perinatal hypoxic-ischemic (HI) brain injury is unknown. Allopurinol reduces neutrophil accumulation after tissue ischemia and is protective against HI brain injury. This study was designed to investigate how neutrophils contribute to perinatal hypoxic ischemic brain injury and how neutropenia compared with allopurinol in its neuroprotective effects. A HI insult was produced in the right cerebral hemisphere of 7-d-old rats by right common carotid artery ligation and systemic hypoxia. Half the rats were rendered neutropenic with an anti-neutrophil serum (ANS). At 15 min of recovery from hypoxia, half the neutropenic and nonneutropenic rats received allopurinol (135 mg/kg, s.c.). The protective effect of the four treatment combinations was determined on brain swelling at 42 h of recovery. Neutropenia reduced brain swelling by about 70%, p < 0.01. Allopurinol alone produced similar protection so that the relatively small number of animals studied did not permit assessment of an additive effect. Neutrophil accumulation in cerebral hemispheres was measured by myeloperoxidase (MPO) activity assay and by neutrophil counts in 6-microm sections stained by MPO and ANS immunostaining. MPO activity peaked between 4 and 8 h of recovery in both hemispheres. Hemispheric neutrophil counts peaked at the end of the HI insult and again at 18 h of recovery. Neutrophils were stained within blood vessels and did not infiltrate the injured brain before infarction had occurred. We conclude that neutrophils contribute to HI brain injury in the neonate and that neutrophil depletion before the insult is neuroprotective.

Neuropathology of normothermic circulatory arrest in newborn dogs

Neuropathologic findings are described, for the first time, in a neonatal dog model of circulatory arrest in normothermic conditions, and the findings are compared to those reported in neonatal dogs with hypothermic circulatory arrest. Total circulatory arrest was produced in 3- to 6-day-old anesthetized, paralyzed and ventilated, normothermic dogs either by asphyxiation or cardioplegia. Duration of circulatory arrest was 8-20 min and 10-40 min in asphyxiated and cardioplegic animals, respectively. The animals were resuscitated and maintained under controlled systemic physiologic conditions until neuropathologic examination after 8 or 24 h of recovery. The results suggest that the minimal durations of circulatory arrest for brain damage to occur following asphyxia or cardioplegia are 10 and 15 min, respectively. Ischemic lesions in both groups consisted of neuronal necrosis and involved mainly the brain stem structures, particularly the reticular nuclei and the spinal cord gray matter. The medulla was more severely involved than midbrain and pons. There was a direct correlation between the length of circulatory arrest and the severity of damage in the medulla (P = 0.001) and overall brain stem damage (P = 0.004) in animals with cardioplegia, but not in animals with asphyxia. These findings are compared to the neuropathologic changes previously described in newborn dogs subjected to hypothermic circulatory arrest, in which ischemic lesions are focused on the cerebral cortex and basal ganglia. It is concluded that hypothermia in this model not only prolongs the period of circulatory arrest that is required to produce brain damage, but also shifts the pattern of regional ischemic vulnerability from caudal to more rostral structures.

Effect of hyperglycemia on ischemic brain damage during hypothermic circulatory arrest in newborn dogs

The effect of hyperglycemia on ischemic brain damage was investigated in a newborn dog model of hypothermic circulatory arrest. Newborn dogs were anesthetized with halothane, paralyzed, and artificially ventilated to maintain normoxia and acid-base balance. Animals were surface-cooled to 20 degrees C, after which cardiac arrest was effected with i.v. KCl. Before surface cooling, one-half of the dogs (n = 12) received a bolus injection of 50% glucose to increase plasma glucose concentrations to approximately 33 mmol/L (600 mg/dL); control littermates (n = 12) received an equivalent volume of 1 N saline. The dogs remained asystolic for 1.75 h, after which cardiopulmonary resuscitation was accomplished. All animals survived, were allowed to recover from anesthesia at 37 degrees C, and were maintained for 8 h of recovery, at which interval they underwent perfusion-fixation of their brains for pathologic analysis. Histologic grading of brain damage showed no statistically significant difference in the severity of neuronal necrosis within the cerebral cortex or caudate nucleus between hyperglycemic and normoglycemic littermates, with greater brain damage apparent in the amygdaloid nucleus of the hyperglycemic dogs (p < 0.02). Brainstem injury occurred more frequently in the hyperglycemic animals (p < 0.05). Correlation of coefficients analyses revealed a positive correlation between the severity of brain damage and plasma glucose concentration for both the caudate nucleus and amygdaloid nucleus but not for the cerebral cortex. The findings suggest that hyperglycemia superimposed upon hypothermic circulatory arrest in the newborn dog accentuates brain damage only in selected regions of the brain, especially the caudate and amygdaloid nuclei and brainstem, excluding the cerebral cortex.

Ganglion cell-containing tumors of the pituitary gland

The ganglion cell-containing tumors of the pituitary are rare lesions of undetermined histogenesis and nosology. A review of the literature revealed 42 such tumors, including the 3 cases described below. On the basis of this review, the tumors were divided into two histologic groups, one consisting of both adenomatous and gangliocytic elements (32 cases), and the other of the gangliocytic component only (10 cases). The first group of tumors were more common in females (23 of 32 cases) and were often active endocrinologically (28 of 32 cases), and acromegaly was the most common manifestation (19 cases). The second group was also more common in females (7 of 10 cases) but was less frequently active endocrinologically (3 of 19 cases). We review histologic and immunocytochemical findings in these tumors and discuss their histogenesis. We propose that the term mixed pituitary adenoma-gangliocytoma be used for the first group and gangliocytoma for the second. The two groups should be kept separate until their histogenesis is better understood.

Cerebrospinal fluid concentrations of glutamate and GABA during perinatal cerebral hypoxia-ischemia and seizures

Cerebrospinal fluid (CSF) concentrations of glutamate and gamma- aminobutyric acid (GABA), as estimates of levels in the extracellular compartment of brain, were determined in 7-day postnatal rats at the terminus of hypoxia-ischemia and during status epilepticus, induced with bicuculline, at 2 and 24 h of recovery. Hypoxia-ischemia was associated with increased CSF glutamate, which was not increased further during status epilepticus. In contrast, CSF GABA was increased by hypoxia-ischemia as well as by status epilepticus during recovery. CSF glutamate/GABA ratios in rat pups subjected to status epilepticus with or without prior hypoxia-ischemia were lower than control animals during recovery. The lack of any significant increase in glutamate or in the glutamate/GABA ratio during status epilepticus would preclude any neuronal injury from occurring in those immature rats sustaining seizures alone or any accentuation of brain damage in those animals subjected to prior cerebral hypoxia-ischemia.

Laminin beta 2 chain and adhalin deficiency in the skeletal muscle of Walker-Warburg syndrome (cerebro-ocular dysplasia-muscular dystrophy)

Muscular dystrophy may be caused by disturbances in a number of muscle proteins that appear to be part of a chain of interacting molecules that includes cytoskeletal, cell membrane, and basement membrane components. We found that the skeletal muscle cells in two cases of Walker-Warburg syndrome were severely deficient in the laminin beta 2 chain and in adhalin. The findings indicate that these two proteins are key molecules in the interactive protein complex conferring muscle stability and cell survival.

Temporal evolution of neuropathologic changes in an immature rat model of cerebral hypoxia: a light microscopic study

The sequential evolution of neuropathologic changes was studied in an immature model of cerebral hypoxia-ischemia. According, 7-day postnatal rats were subjected to unilateral common carotid artery ligation combined with 2 h of hypoxia (breathing in 8% oxygen) and their brains were examined by light microscopy at recovery intervals ranging from 0 to 3 weeks. Immediately following hypoxia, a large area with a pale staining border was noted occupying most of the cerebral hemisphere ipsilateral (IL) to the occluded common carotid artery; in approximately half of the brains the dorsomedial cortex of the contralateral (CL) hemisphere was also involved. Most neurons in the pale area had nuclei containing a coarse granular condensation of chromatin. Within a few hours, the majority of neurons in the IL hemisphere had developed pyknotic nuclei and clear or eosinophilic perikarya. After 24 h these changes had evolved in the majority of brains into coagulation necrosis (infarction) in the IL hemisphere and foci of selective neuronal necrosis in the CL cortex. Within a few days infarcts became partially cavitated, and by 3 weeks a smooth-walled cystic infarct had developed. Activated microglia/macrophages and reactive astrocytes were first seen at 4 and 24 h, respectively. No parenchymal neutrophilic infiltrate was seen at any time point.

Effect of status epilepticus on hypoxic-ischemic brain damage in the immature rat

Seven-day postnatal rats were subjected to unilateral common carotid artery ligation, 3 h after which they were subjected to hypoxia with 8% oxygen at 37 degrees C for 2 h. Thereafter, they received multiple s.c. injection(s) of bicuculline (6 mg/kg) adequate to produce behaviorally apparent seizures lasting greater than 1 h (status epilepticus). Repeated episodes of status epilepticus at 2, 6, and 12 h of recovery from hypoxia-ischemia (HI) produced a mortality rate of 53%. Among the survivors, there was no statistically significant difference in the extent of brain damage between convulsing and non-convulsing HI controls, analyzed at 30 d of age. Histopathologic examination for acute lesions also indicated no difference in the severity of brain damage between dead and surviving rat pups subjected to status epilepticus, indicating that mortality was not related to the severity of prior HI brain damage. Those immature rats that died during status epilepticus exhibited lower blood glucose concentrations (1.75 +/- 0.35 mmol/L) compared with surviving, convulsing animals (4.25 +/- 0.51 mmol/L; p = 0.016). Glucose supplementation (0.1 mL of 50% glucose) early during status epilepticus improved survival and significantly prolonged seizure activity (90 +/- 14 min) compared with non-glucose treated, convulsing littermates (47 +/- 10 min; p = 0.02). Glucose supplementation did not increase the extent of brain damage despite improved survival and increased duration of seizure activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon dioxide protects the perinatal brain from hypoxic-ischemic damage: an experimental study in the immature rat

BACKGROUND AND OBJECTIVE

Clinical investigations suggest that premature infants who require mechanical ventilation from respiratory distress syndrome are at increased risk for periventricular leukomalacia if hypocapnia occurs during respiratory management. The question remains as to the contribution of hypocapnia to hypoxic-ischemic brain damage and whether or not hypercapnia is neuroprotective.

METHODS

Seven-day postnatal rats underwent unilateral common carotid artery ligation followed thereafter by exposure to systemic hypoxia with 8% oxygen (O2) combined with either 0, 3, 6, or 9% carbon dioxide (CO2) for 2.5 hours at 37 degrees C. Survivors underwent neuropathologic examination at 30 days of postnatal age, and their brains were categorized as follows: 0 = normal; 1 = mild atrophy; 2 = moderate atrophy; 3 = atrophy with cystic cavitation < 3 mm; 4 = cystic cavitation > 3 mm of the cerebral hemisphere ipsilateral to the carotid artery ligation. The width of the ipsilateral hemisphere also was determined on a posterior coronal section and compared with that of the contralateral hemisphere to ascertain the severity of cerebral atrophy/cavitation. Data were analyzed by linear models.

RESULTS

CO2 tensions averaged 26, 42, 54, and 71 mm Hg in the 0, 3, 6, and 9% CO2 exposed animals, respectively, during systemic hypoxia. Blood O2 tensions during hypoxia were not different among the four groups and averaged 34.7 mm Hg. Neuropathologic results showed that 30/38 (79%) rats exposed to 3% CO2 showed either no or mild brain damage compared with 13/33 (39%) controls (0% CO2). Cystic cavitation occurred in only four CO2 exposed rat pups compared with 14 controls (P = .001). At 6% CO2 exposure, all of 20 rat pups showed either no damage or mild atrophy compared with controls (P < .001); and at 9% CO2 exposure, 19/23 (83%) rat pups showed no or mild damage compared with controls (P < .001). The data also showed that the greatest reduction in brain damage occurred in immature rats exposed to 6% CO2 with slightly less protection at 9% CO2 (P = .012), the latter comparable with the severity of brain damage sustained by animals inhaling 3% CO2. Analyses of coronal width ratios at each CO2 exposure provided results comparable with those of the gross neuropathology scores.

CONCLUSIONS

The results indicate that in an immature rat model normocapnic cerebral hypoxia-ischemia is associated with less severe brain damage than in hypocapnic hypoxia-ischemia and that mild hypercapnia is more protective than normocapnia. The findings in an experimental model merit further animal investigations as well as a clinical reappraisal of the ventilatory management of sick newborn human infants.

Effect of hypoxia/ischemia on bicuculline-induced seizures in immature rats: behavioral and electrocortical phenomena

The relation between hypoxia/ischemia and subsequent alterations in seizure susceptibility in developing brain remains unclear. We assessed the behavioral and electrocorticographic (ECoG) effects of hypoxic/ischemic brain damage on bicuculline (BIC)-induced seizures in 7-day postnatal rats, and determined maturational changes in seizure susceptibility, behavior and ECoG activity. Rat pups were subjected to unilateral common carotid artery ligation, followed by exposure to 8% O2 at 37 degrees C for 2 h, an insult that produces brain damage in the cerebral hemisphere ipsilateral to carotid artery occlusion. The experimental group consisted of rat pups previously subjected to hypoxia/ischemia; control littermates received neither arterial ligation nor systemic hypoxia. Experimental animals received 4, 5, or 6 mg/kg BIC subcutaneously (s.c.) at 2 and 24 h, and at 3, 7, and 21 days of recovery from hypoxia/ischemia. Two animals at each interval of recovery, 1 each from the experimental and control groups, were used for ECoG monitoring. After BIC injection, animal behavior was observed for 2 h. Behaviors and seizures were classified in five categories based on severity, duration, and character: 1, mild irritability; 2, few clonic seizures and agitation; 3, few tonic-clonic seizures with swimming movements; 4, frequent tonic-clonic seizures with apneic episodes; 5, continuous tonic-clonic seizures and death. Rat pups previously subjected to hypoxia/ischemia had lesser seizure susceptibility than controls at 2-h recovery (p < 0.05) and greater susceptibility than controls at 24 h (p < 0.05). Tonic seizures were prominent at 2 and 24 h in both the experimental and control groups, whereas lesion-sided circling was prominent only in the hypoxic/ischemic rat pups.(ABSTRACT TRUNCATED AT 250 WORDS)

MR of giant arachnoid granulation, a normal variant presenting as a mass within the dural venous sinus

We report three cases of masses within the cerebral dural venous sinuses shown with either MR or angiography. The dural venous sinuses of 10 patients without known venous disease were examined at autopsy. In two patients, three giant arachnoid granulations were identified. On the basis of the literature and our limited autopsy series, we suggest that these lesions identified at imaging are giant arachnoid granulations, normal variants of no known clinical significance.

The asymmetric mamillary body: association with medial temporal lobe disease demonstrated with MR

PURPOSE

To determine whether mamillary body atrophy is caused by deafferentation of the mamillary body in patients with mesial temporal sclerosis.

METHODS

We studied 36 patients with thin-section MR to assess mamillary body symmetry. These patients included 10 control subjects without seizures and 26 patients with a history of seizures. Thin-section T1 scans were available for all cases. The patients with epilepsy underwent axial and coronal T2 scans as well.

RESULTS

In five of eight cases with prior medial temporal lobe resection for intractable epilepsy, there was evidence of unilateral mamillary body atrophy ipsilateral to the resection. Similar findings were evident in three of six patients with MR findings of mesial temporal sclerosis without surgery. Two patients with medial temporal stroke or tumor also had ipsilateral mamillary body atrophy.

CONCLUSION

These findings provide support for the proposed mechanism of mamillary body atrophy caused by prior medial temporal lobe injury.

Differences in intraischemic temperature influence neurological outcome after deep hypothermic circulatory arrest in newborn dogs

BACKGROUND AND PURPOSE

Hypothermia to core temperatures ranging from 16 degrees C to 24 degrees C has become an established procedure to extend the "safe" interval of cardiac arrest during open heart surgery in human infants. The present experiment was designed to ascertain whether differences in core (rectal) temperature during hypothermic circulatory arrest influence the presence and extent of ischemic brain damage in newborn dogs.

METHODS

Newborn dogs (postnatal age, 3 to 5 days) were anesthetized with halothane (4% induction; 0.5% maintenance), intubated, paralyzed, and artificially ventilated with 70% nitrous oxide/30% oxygen. Thereafter, the dogs were surface cooled with ice packs to either 16 degrees C (n = 6), 20 degrees C (n = 8), or 24 degrees C (n = 6). The dogs then were subjected to circulatory arrest for 1.75 hours by the intravenous injection of KCl, following which they were resuscitated with intravenous NaHCO3 and epinephrine, artificial ventilation, and closed chest cardiac massage. Those dogs that survived for 8 hours of recovery (n = 16) underwent neurobehavioral examination followed by perfusion-fixation of their brains for pathological analysis.

RESULTS

All newborn dogs were successfully resuscitated after 1.75 hours of cardiac arrest, rewarmed to 37 degrees C, and ultimately weaned from anesthesia and ventilatory support. Four dogs sustained secondary systemic complications with death at 4 to 7 hours. All surviving dogs remained stable, with systemic blood pressure, heart rate, arterial oxygen, and acid-base balance within the normal, normothermic range. Of the 16 surviving dogs, all except 1 showed histological evidence of brain damage at 8 hours of recovery. Morphometric analysis of the number of necrotic neurons in the vulnerable gray matter structures showed the greatest damage to cerebral cortex at 24 degrees C and the least damage to this structure at 16 degrees C by either regression analysis (r = .62; P = .01) or a repeated-measures model (P = .008). The extent of damage to the caudate nucleus was similar in the three temperature groups, while damage to the amygdaloid nucleus was greater at 24 degrees C compared with 20 degrees C but with no difference in the severity of damage between 20 degrees C and 16 degrees C. A close correlation existed between neurobehavioral deficits in the surviving dogs and the severity of damage to the cerebral cortex (r = .72; P = .001).

CONCLUSIONS

The findings indicate that differences in intraischemic core temperature during deep hypothermic circulatory arrest influence the severity of damage to the cerebral cortex of newborn dogs. Specifically, the lower the temperature below 24 degrees C, the more protected the structure from ischemic injury. Furthermore, the greater the cortical damage, the more severe the neurobehavioral deficits. Such was not the case for the amygdaloid nucleus and especially for the caudate nucleus. Accordingly, differences in core temperature, even at very low levels, appear critical for optimal protection of the newborn brain during hypothermic circulatory arrest.

The effect of focal cerebral cooling on perinatal hypoxic-ischemic brain damage

We describe a method of focal cooling of the head and its effects on hypoxic-ischemic cerebral damage in neonatal rat. Focal cooling of the head was obtained by positioning a catheter under the scalp ipsilateral to the ligated common carotid artery and by running cold water through the catheter during 2 h of systemic hypoxia. Hypoxia was produced in neonatal rats by breathing 8% oxygen for 2 h in a 37 degrees C chamber. Animals underwent focal cooling with ipsilateral scalp temperatures ranging from 22 degrees C to 35 degrees C. Temperature recordings from the ipsilateral scalp, cerebral hemisphere (dorsal hippocampus) and core (rectal) were obtained. The results suggest that the method is effective in cooling of brain and also to a lesser extent in lowering of the core temperature. At a mean scalp temperature of 28 degrees C, mean hippocampal temperature in hypoxic rat was 29.5 degrees C and mean core temperature in hypoxic rat was 32.8 degrees C. At a lower scalp temperature of 22 degrees C, mean hippocampal temperature in hypoxic rat was 24.7 degrees C and mean core temperature was 31.3 degrees C. Neuropathologic examination 3-4 days following hypoxia-ischemia showed that focal cooling with a scalp temperature of lower than 28 degrees C completely protected from brain damage, and that there was a trend towards greater damage with higher scalp temperatures.

Cerebral energy metabolism during hypoxia-ischemia correlates with brain damage: a 31P NMR study in unanesthetized immature rats

The association between the ultimate brain damage resulting from unilateral hypoxic-ischemic insult (HI) and the changes in high-energy metabolites, measured by noninvasive phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy during the insult, was evaluated in 7-day postnatal rats. When the NMR metabolite levels were integrated over the last 1.5 h out of 2.5 h of HI, there was a significant correlation of both the estimator of phosphorylation potential (P < 0.001) and ATP levels (P < 0.01) with histologic score of damage and area morphometry. In particular, the development of cerebral infarction could be predicted from the NMR evaluation (P < 0.005). These findings suggest that a large disturbance in cellular energy metabolism is a prerequisite for the subsequent neuropathological alterations in this model.

Adipose tissue and smooth muscle in a primitive neuroectodermal tumor of cerebrum

We describe a case of an occipital lobe primitive neuroectodermal tumor (PNET) in a 60-year-old man with immunocytochemical evidence of neuronal, glial, smooth muscle and adipose tissue differentiation in the primary tumor and its metastases. This is the first case of PNET of cerebrum in which adipose tissue and smooth muscle has been demonstrated. The possible cells of origin for these mesenchymal elements is discussed.

Effect of unilateral perinatal hypoxic-ischemic brain damage on the gross development of opposite cerebral hemisphere

The effect of unilateral perinatal cerebral hypoxic-ischemic damage on the gross development of the opposite hemisphere was investigated in immature rats. Eight-day-old rats underwent unilateral common carotid artery ligation followed by exposure to hypoxia (8% oxygen) ranging from 1 to 2 h at 37 degrees C. The animals were sacrificed 3 weeks later, and brain damage was assessed histologically, by weighing the cerebral hemispheres, and by measuring hemispheric cross-sectional area and diameter as well as the thickness of neocortex. There were no significant differences in either the size or cortical thickness of the cerebral hemisphere contralateral to the damaged hemisphere compared to those of controls. The results are comparable to the effect of unilateral perinatal hemispheric decortication and hemispherectomy on the growth of the contralateral hemisphere and suggest that: (1) perinatal damage to one cerebral hemisphere does not significantly alter the size of the other hemisphere, and (2) the contralateral hemisphere may be used as a 'normal' reference in evaluating the extent of atrophy or infarction of a cerebral hemisphere damaged earlier by perinatal hypoxia-ischemia.

Low diagnostic yield of sural nerve biopsy in patients with peripheral neuropathy and primary amyloidosis

Patients with primary amyloidosis may develop peripheral neuropathy as an early feature. Sural nerve biopsy is reported to be a sensitive method for diagnosing amyloidosis in such patients. We identified nine patients, ultimately diagnosed as having amyloidosis, who were referred for peripheral neuropathy of undetermined etiology. In six, a sural nerve biopsy demonstrated no amyloid. Subsequent examination of other tissue or of the contralateral sural nerve eventually resulted in the correct diagnosis. We conclude that sural nerve biopsy may be less sensitive than previously believed for the diagnosis of amyloidosis in patients with peripheral neuropathy secondary to amyloid. When the clinical suspicion of amyloidosis is high, a nondiagnostic sural nerve biopsy should not discourage the performance of further investigative studies.

Influence of mild hypothermia on hypoxic-ischemic brain damage in the immature rat

Recent studies in adult animals have shown that even small decreases in brain or core temperature ameliorate the damage resulting from hypoxic-ischemic insults. To determine the effect of minor reductions in ambient temperature either during or after an hypoxic-ischemic insult on the brain of the immature rat, 7-d-postnatal rat pups underwent unilateral common carotid artery ligation followed by exposure to hypoxia in 8% oxygen for 3 h. Control animals were maintained at 37 degrees C during hypoxia-ischemia. Intraischemic hypothermia was induced during the insult at temperatures of 34 degrees C and 31 degrees C. Postischemic hypothermia was induced by exposing rat pups that underwent hypoxia at 37 degrees C to recovering environments of 34 degrees C and 31 degrees C. Temperatures were recorded every 15 min from thermistor probes placed in the ipsilateral hemisphere and rectally. Neuropathologic alterations were assessed at 30 postnatal d. During hypoxia, animals became poikilothermic. Brain damage occurred in 90% of rat pups exposed to hypoxia-ischemia at 37 degrees C. Cerebral injury significantly decreased with decreasing temperatures during hypoxia-ischemia (p < 0.01). Only 30% of rats had brain damage when exposed to hypoxia-ischemia at 34 degrees C, and none of the rats exposed at 31 degrees C had brain damage. In contrast, there was no difference in the extent of cerebral injury between rat pups recovered under hypothermic conditions of either 34 degrees C or 31 degrees C compared with those recovered at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of anesthetics on neuropathologic sequelae of status epilepticus in rats

We compared the efficacy of four different classes of anesthetics to arrest the progression of brain damage after chemoconvulsant-induced seizures in rats. In two series of experiments, ventilated, paralyzed Long-Evans rats were subjected to 30 or 45 min of continuous seizures induced by intravenous (IV) mercaptopropionic acid (MPA) or inhaled flurothyl, respectively. In the first series, seizures produced with MPA were treated with: 1) thiopental, 15 mg/kg IV bolus (controls); 2) thiopental, 27 mg/kg IV followed by 20.9 mg.kg-1.h-1 for 2 h; 3) isoflurane 4% inhaled concentration for 1 min followed by 1%-2% for 2 h; 4) ketamine 30 mg/kg IV followed by 9.12 mg.kg-1.h-1 for 2 h; 5) midazolam 25 mg/kg IV followed by 9.7 mg.kg-1.h-1 for 2 h. In a second series, seizures were produced by flurothyl and, based on suggestive results in the MPA series, control rats were compared with rats receiving midazolam 25 mg/kg IV followed by 9.7 mg.kg-1.h-1. In all instances, seizure activity, recorded by electroencephalograph, stopped with anesthetic treatment. In MPA-treated rats extranigral damage was mild, with no differences apparent between anesthetics. Control animals sustained severe lesions in the substantia nigra pars reticulata (SNPR). No statistically significant differences between anesthetic groups were present, although an effect was suggested for midazolam to decrease SNPR lesional area (P = 0.06). In flurothyl-treated rats, there were significant reductions in SNPR neuropathologic grade (P = 0.025) and lesional area (P = 0.025) with midazolam. We conclude that midazolam attenuates postseizure SNPR damage in rats.

Necrotizing infundibulo-hypophysitis: a unique syndrome of diabetes insipidus and hypopituitarism

Clinical, radiological, histological, and anatomical features in 2 patients with necrotizing infundibulo-hypophysitis are reported. The patients presented with a combination of diabetes insipidus and hypopituitarism. Each was found to have a sellar mass lesion with an abnormally thickened enlarged pituitary stalk that intensively enhanced on contrast magnetic resonance imaging. They were suspected to have pituitary tumors with suprasellar extension. However, tissue obtained at transphenoidal surgery revealed necrosis, fibrosis, and chronic inflammation; there was no evidence of infiltrative, infective, or neoplastic disease processes. Postoperatively, they continued to have diabetes insipidus and hypopituitarism despite radiological improvement and steroid therapy. Several clinical and anatomical features distinguish these 2 cases from classical lymphocytic hypophysitis, the most common entity in the differential diagnosis. Specifically, diabetes insipidus has not been observed preoperatively in 30 cases of lymphocytic hypophysitis, but was present in the 2 cases reported. Histological evidence of tissue necrosis present in these 2 cases is not a feature of lymphocytic hypophysitis. Pituitary stalk involvement on magnetic resonance imaging or computed tomographic scan present in these 2 cases is highly unusual in lymphocytic hypophysitis. Finally, 29 of 30 cases of lymphocytic hypophysitis were females, whereas the 2 cases reported are men. On the basis of these disparate findings, we suggest that these 2 cases represent a unique syndrome, which may be recognized clinically and radiologically.

Allopurinol administered after inducing hypoxia-ischemia reduces brain injury in 7-day-old rats

We determined that treatment of immature rats with allopurinol at 15 min after cerebral hypoxia-ischemia reduces brain damage. Seven-d postnatal rats were subjected to right common carotid artery ligation followed by 2.25 h of hypoxia (8% O2). At 15 min of recovery in room air, the rat pups received either allopurinol (135 mg/kg s.c.) or saline. Some of the rats (n = 65) were killed at 42 h of recovery for measurement of cerebral hemispheric water content. Other animals (n = 63) were killed at 30 d for morphologic assessment of the severity of damage. In separate rats, we measured the levels of allopurinol and its metabolites in serum and in the brain around the time of peak serum levels. We also determined the effect of allopurinol on rat pup body temperature. Allopurinol reduced the increase in right hemisphere water content and markedly reduced atrophy. No cavitary lesions were seen in the 31 allopurinol-treated rats, whereas 15 of 32 saline-treated rats had cavitary cerebral lesions. Histologic examination confirmed that the allopurinol-treated rats had less brain injury. Serum allopurinol and oxypurinol peaked between 0.5 and 1 h after allopurinol injection. Their peak serum concentrations at 0.75 h postinjection combined was between 360 and 510 microM. Allopurinol did not lower rectal temperature more than 0.04 degrees C. In conclusion, high-dose allopurinol administered at 15 min of recovery from cerebral hypoxia-ischemia markedly reduces both acute brain edema and long-term cerebral injury in immature rats.

Neuropathologic aspects of hypothermic circulatory arrest in newborn dogs

A model of hypothermic circulatory arrest with recovery has been developed in the newborn dog. Eleven puppies were anesthetized with halothane, paralyzed and artificially ventilated with 70% nitrous oxide -30% oxygen to paO2 > 60 mm Hg, paCO2 = 33-42 mm Hg and pHa = 7.35-7.42. Animals were surface cooled to 20 degrees C, following which cardiac arrest was effected with i.v. KCl. Dogs remained asystolic without ventilation for 1.0, 1.5 or 1.75. Resuscitation was accomplished with closed-chest compression, mechanical ventilation, i.v. epinephrine and NaHCO3, and rewarming to 37 degrees C. Thereafter, the puppies were allowed to recover from anesthesia and maintained for either 18-22 h (n = 9) or 72 h (n = 2), at which time they underwent perfusion-fixation of their brains for pathologic analysis. Of the total, four out of four puppies arrested for 1.0 h exhibited no brain damage, including one recovered for 72 h; whereas one out of three and four out of four puppies arrested for 1.5 and 1.75 h, respectively, showed brain damage predominantly of the cerebral cortex but also of the basal ganglia and amygdaloid nucleus. The hippocampus was spared, even in a 1.75-h-arrested animal which was maintained for 72 h. No differences in pre- or post-arrest systemic blood pressure, heart rate, or acid-base balance were observed between the brain damaged and undamaged animals except for the single damaged animal arrested for 1.5 h, for which the blood pressure prior to cardiac arrest and during recovery was the lowest of all survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Ocular invasion in mucormycosis

The histopathologic findings in a case of ocular invasion in rhinocerebral mucormycosis are described. The findings of hyphae in the inner sclera and marked involvement of the posterior ciliary arteries suggested an arterial route of ocular invasion by fungus. Only five other cases of rhinocerebral mucormycosis with ocular fungal invasion have been reported to our knowledge. All six patients died from the infection. As a group, these cases suggest that the presence of ocular infiltration by fungus may indicate poor prognosis in rhinocerebral mucormycosis.

Effect of insulin-induced and fasting hypoglycemia on perinatal hypoxic-ischemic brain damage

Experiments in adult animals have indicated that hyperglycemia accentuates whereas hypoglycemia ameliorates hypoxic-ischemic brain damage. To determine whether hypoglycemia is protective or deleterious to the perinatal brain subjected to hypoxia-ischemia, 7-d postnatal rats were rendered hypoglycemic either by receiving an s.c. injection of insulin or fasting for 12 h. All rat pups underwent unilateral common carotid artery ligation followed by exposure to 8% oxygen-balance nitrogen at 37 degrees C for 2 h. Control animals (no insulin or fasting) received s.c. injections of normal saline. Mean blood glucose concentrations were 5.4 +/- 0.1, 4.3 +/- 0.2, and 3.4 +/- 0.1 mmol/L for control, insulin, and fasted animals, respectively. Blood beta-hydroxybutyrate concentrations were identical (0.5 +/- 0.1 mmol/L) for control and insulin-treated animals, but more than doubled in concentration in the fasted animals (p less than 0.001). Mortality rates during hypoxia-ischemia were higher in the insulin-treated animals (30%) than in either the fasted (4%) or control (0%) animals (p less than 0.05). Fasted animals showed a significant reduction in hypoxic-ischemic brain damage as compared with either the insulin-treated or control animals. Insulin-treated animals were not significantly different from controls. The findings indicate that 1) insulin induced hypoglycemia does not provide a protective effect on perinatal hypoxic-ischemic brain damage, as in adults; and 2) fasting adequate to produce hypoglycemia and ketonemia improved neuropathologic outcome.

Early onset autosomal dominant progressive muscular dystrophy presenting in childhood as a Becker phenotype--the importance of dystrophin and molecular genetic analysis

We present two cases of autosomal dominant limb girdle muscular dystrophy in a father and son. Both presented in childhood with a classical Becker muscular dystrophy phenotype. The father had initially been informed that he would not have affected children. After the diagnosis of muscular dystrophy in the son, immunoblot analysis was performed on muscle and revealed normal dystrophin. The polymerase chain reaction did not show any deletions in the dystrophin gene, and the father's dystrophin gene was not passed to his son. These cases demonstrate that autosomal dominant muscular dystrophy may present in childhood, and that dystrophin and molecular genetic analyses should be performed when considering the diagnosis of childhood muscular dystrophy, even in the presence of a classical phenotype.

Cerebro-ocular dysplasia--muscular dystrophy (Walker Warburg) syndrome. Findings in 20-week-old fetus

A 20-week fetus affected with cerebro-ocular dysplasia and muscular dystrophy (Walker-Warburg Syndrome) is reported. The central nervous system (CNS) findings were typical of those previously described in this disorder, and were characterized by lissencephaly, hydrocephalus, and cerebral and cerebellar cortical dysplasia with glial and neuronal displacement into the leptomeninges. In addition, severe hypoplasia of pyramidal tracts were noted in the brain stem and spinal cord, as well as malformation of the inferior olivary and dentate nuclei. Skeletal muscle and eyes appeared normal on light microscopy. The genetic defect in this disorder is expressed in the CNS early during the first trimester and causes a marked disorder of cellular migration. Overt changes in muscle occur during a later period. The changes in the CNS are similar to, but more severe than, those found in Fukuyama congenital muscular dystrophy, and both may represent a failure of constraint of neuronal migration. Whether the syndromes characterized by cerebro-ocular dysplasia and muscular dystrophy are genetically heterogeneous or allelic variations is unknown. Molecular genetic analysis should elucidate this question.

Sternohyoid muscle biopsy. A diagnostic technique in respiratory failure of neuromuscular origin

Patients with neuromuscular disease may develop respiratory failure requiring mechanical ventilation. We describe a sternohyoid muscle biopsy technique as a diagnostic aid in such patients undergoing tracheostomy for prolonged ventilatory support. The biopsy procedure is quick and without added discomfort or morbidity for the patient. Our preliminary observations in three patients suggest that the sternohyoid muscle biopsy may be a useful diagnostic tool in this selected group of patients.

Extramedullary hematopoiesis in cerebellar hemangioblastoma

Extramedullary hematopoiesis and paraneoplastic erythrocytosis are uncommon in cerebellar hemangioblastoma, and their concomitant occurrence has not been reported. In a study of 26 cases of hemangioblastoma, we found extramedullary hematopoiesis in 4 tumors; one was associated with erythrocytosis. The significance of this association and the possible histogenetic origin of extramedullary hematopoiesis in cerebellar hemangioblastoma are discussed.

Brain energy consumption in ethanol-treated, Long-Evans rats

The cerebral metabolic rate of glucose utilization (CMRGlc) was measured in rats fed liquid diets containing ethanol for 8 wk, after removal of ethanol from the diet and after acute ethanol intoxication. Control rats were pair fed the liquid diets containing isoenergetic amounts of dextrin-maltose. Quantitative autogradiography using [6-14C]glucose measured CMRGlc at the level of individual structures. Digital image techniques created stereograms of brain energy consumption from the autoradiographs. These techniques provided information about CMRGlc throughout the brain. Rats given the ethanol liquid diet drank constantly throughout the day and night. Neuropathological examination of brain revealed no abnormalities from ethanol consumption. Acute ethanol administration to control rats produced a decrease in CMRGlc throughout the brain that was most prominent in structures concerning auditory, visual, memory and motor functions. Chronic ethanol consumption did not reduce CMRGlc to the same degree as acute ethanol intoxication; in fact, it affected only a few structures. The removal of ethanol from chronic ethanol-treated rats for a period of 18 h caused CMRGlc to rise above control values throughout the brain. However, there were no seizures or other evidence of brain dysfunction.

Neuropathology of remote hypoxic-ischemic damage in the immature rat

This study was undertaken to determine: (a) the duration of hypoxia required to produce brain damage in immature rats with unilateral carotid artery ligation (Levine technique); (b) the regions of immature brain most vulnerable to hypoxia-ischemia (HI); and (c) the neuropathology of the remote HI insult. To this end, 7-day postnatal rats, subjected to unilateral carotid artery ligation combined with hypoxia of varying durations (45, 60, 75 or 90 min), were killed at 30 days of postnatal age and their brains examined by light microscopy. The results indicated that a longer duration of HI was more likely to produce brain lesions and that the extent and severity of the lesions closely correlated with the length of HI. Shorter intervals of HI primarily damaged the cerebral cortex and hippocampus, while longer periods resulted in more extensive damage and were often associated with cavitary lesions of the cerebral hemisphere. Comparison of HI brain damage produced by the Levine technique in immature and adult rats suggested that in immature rats: (a) the cavitary lesions were common; (b) the non-cavitary cortical lesions had a tendency to show a vertical band-like distribution - a pattern never seen in adults; and (c) the lesions often showed mineralization. The similarities between these experimentally produced HI cerebral lesions and those observed in the developing human brain, such as ulegyria and porencephaly, are discussed.

Spinal cord abnormalities in caudal regression syndrome

Caudal regression syndrome includes malformations ranging from mild forms of sacral agenesis to severe limb anomalies referred to as sirenomelia. The latter, in addition to sacral anomalies, shows malformed single lower limb and agenesis of rectum and genitourinary tracts. We report the neuropathologic examination in four infants, three with sirenomelia and one with lumbosacral agenesis. Brain and spinal cord were normal except for the structures in the caudal region of the spinal cord that were abnormal in all four cases. The first sirenomelic case with a mild sacral hypoplasia had only minor fusion of a few sacral roots and a slightly low-positioned conus medullaris. The second sirenomelic case with an intermediate degree of sacral hypoplasia had fusion of some of the sacral roots and ganglia, spinal ganglion cell heterotopias, filar lipoma and absence of the last sacral roots and ganglia. The third sirenomelic case with a severe degree of sacral hypoplasia showed additional tethering of the spinal cord. Case four with the agenesis of the lumbosacral spine had a total lack of the lumbosacral spinal cord, and dysplasia of the T11 and T12 cord segments. These findings suggest that the extent of anomalies of the caudal spinal cord structures in the caudal regression syndrome are roughly proportional to the anomalies of the vertebral column, and that they may constitute some of the main components of this syndrome.

Five children with del (2)(q31q33) and one individual with dup (2)(q31q33) from a single family: review of brain, cardiac, and limb malformations

Five matings to a dir ins (6;2)(q16;q31q33) carrier have produced a high frequency (42%) of offspring with unbalanced karyotypes. Five children have the derivative chromosome 2 resulting in del (2)(q31q33) and one individual received the derivative chromosome 6 leading to dup (2)(q31q33). The findings associated with the deletion include pre- and postnatal growth retardation, developmental delay, minor facial anomalies, seizures, complex structural heart defects, and limb deficiency. Autopsy of one individual showed complex brain malformations including hydrocephalus secondary to obstruction of the foramina of Monro, extensive heterotopias and polymicrogyria, and an unusual form of total anomalous pulmonary venous return. We compare the findings in these children to those of previously reported cases and construct an overview of the range of anomalies. Apparently, no other individual with dup (2)(q31q33) has been described. We compare the physical peculiarities of our patient with those of individuals with duplications of overlapping regions of 2q.