Cortical spreading depression protects against subsequent focal cerebral ischemia in rats

Specific, high-affinity angiotensin II (A II) receptors were observed on granulosa and thecal cells of preovulatory ovarian follicles from immature PMSG-treated rabbits. Scatchard analysis of 125I-[Sar1,Ile8]A II binding to freshly prepared cells was indicative of only one class of binding sites. Kd values were 0.26 +/- 0.11 nM and 0.18 +/- 0.02 nM, densities of A II receptors were 0.06 +/- 0.02 fmol/10(5) cells and 0.08 +/- 0.01 fmol/10(5) cells for granulosa and thecal cells, respectively. When cells were incubated for 48 h with hCG, Kd values were of the same order of magnitude, but the amount of A II receptors was increased 2-fold in granulosa and 4-fold in theca. Using subtype specific ligands (Losartan for AT1 and PD 123319 for AT2) in competitive binding experiments, A II receptors were found to be of the AT1 type on both granulosa and thecal cells freshly prepared or incubated 48 h in vitro. These results establishing the existence of high affinity AT1 receptors on the two cell types of the rabbit preovulatory follicles contrast with previous observations showing the presence of AT2 receptors on granulosa or theca from several species.     

Overexpression of human glutathione peroxidase protects transgenic mice against focal cerebral ischemia/reperfusion damage

As stroke is a major cause of disability and death in the western world, there is great interest in the basic mechanisms by which ischemia/reperfusion (I/R) causes damage. To this end, extensive research has been carried out which identifies reactive oxygen species (ROS) as key participants in brain damage resultant from I/R. Brain tissue is protected from ROS damage by antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione peroxidase (GP). Overexpression of SOD in transgenic mice has already been demonstrated to confer protection against I/R damage in murine stroke models. We are using transgenic mice overexpressing the intracellular form of glutathione peroxidase (GP1) to determine the protective capacity of overexpression of this enzyme on stroke damage. 1 h of focal cerebral ischemia followed by 24 h of reperfusion was induced using the intraliminal suture method. Volume of infarction was reduced by 48% in GP1 mice compared to nontransgenic littermates. Brain edema was reduced by 33%. Behavioral deficits agreed with histologic data. Overexpression of glutathione peroxidase confers significant protection against I/R damage in our stroke model possibly through direct scavenging of ROS or through the influencing of signalling mechanisms which lead to tissue damage.     

A mouse model of embolic focal cerebral ischemia

We developed a mouse model of embolic focal cerebral ischemia, in which a fibrin-rich clot was placed at the origin of the middle cerebral artery (MCA) in C57BL/6J mice (n = 31) and B6C3 mice (n = 10). An additional three non-embolized C57BL/6J mice were used as a control. Embolus induction, cerebral vascular perfusion deficit, and consequent ischemic cell damage were confirmed by histopathology, immunohistochemistry, laser confocal microscopy, and regional cerebral blood flow (rCBF) measurements. Reduction in rCBF and cerebral infarct were not detected in the control animals. An embolus was found in all C57BL/6J and B6C3 mice at 24 hours after injection of a clot. Regional CBF in the ipsilateral parietal cortex decreased to 23% (P < 0.05) and 17% (P < 0.05) of preembolization levels immediately and persisted for at least 1 hour in C57BL/6J mice (n = 6) and in B6C3 mice (n = 3), respectively. A significant decrease of rCBF was accompanied by a corresponding reduction of plasma perfusion in the ipsilateral MCA territory. Neurons exhibited marked reduction in microtubule-associated protein-2 immunostaining coincident with the area of perfusion deficit. The percent infarct volume was 30.3% +/- 13.4% for C57BL/6J mice (n = 17), and 38.3% +/- 15.3% for B6C3 mice (n = 7) at 24 hours after embolization. This model of embolic ischemia is relevant to thromboembolic stroke in humans and may be useful to investigate embolic cerebral ischemia in the genetically altered mouse and for evaluation of antiembolic therapies.     

Axonal injury caused by focal cerebral ischemia in the rat

The susceptibility of axons to blunt head injury is well established. However, axonal injury following cerebral ischemia has attracted less attention than damage in gray matter. We have employed immunocytochemical methods to assess the vulnerability of axons to cerebral ischemia in vivo. Immunocytochemistry was performed using antibodies to a synaptosomal-associated protein of 25 kDa (SNAP25), which is transported by fast anterograde transport; the 68-kDa neurofilament subunit (NF68kD); and microtubule-associated protein 5 (MAP5) on sections from rats subjected to 30 min and 1, 2, and 4 h of ischemia induced by permanent middle cerebral artery (MCA) occlusion. After 4 h of occlusion, there was increased SNAP25 immunoreactivity, which was bulbous in appearance, reminiscent of the axonal swellings that occur following blunt head injury. Increased SNAP25 immunoreactivity was present in circumscribed zones in the subcortical white matter and in the axonal tracts at the border of infarction, a pattern similar to that previously described for amyloid precursor protein. Although less marked, similar changes in immunoreactivity in axons were evident following 2 h of ischemia. MAP5 and NF68kD had striking changes in immunoreactivity in axonal tracts permeating the caudate nucleus within the MCA territory at 4 h. The appearance was roughened and disorganized compared with the smooth regular staining in axons within the nonischemic areas. Profiles reminiscent of axonal bulbs were evident in MAP5-stained sections. The changes seen with NF68kD and MAP5 were also evident at 2 h but were more subtle at 1 h. There were no changes in axonal immunoreactivity with SNAP25 or NF68kD at 30 min after MCA occlusion. Altered immunoreactivity following ischemia using SNAP25, MAP5, and NF68kD provides further evidence for the progressive breakdown of the axonal cytoskeleton following an ischemic insult. NF68kD and MAP5 appear to be sensitive markers of the structural disruption of the cytoskeleton, which precedes the subsequent accumulation of SNAP25 within the damaged axons. Axonal cytoskeletal breakdown and disruption of fast axonal transport, which are well-recognized features of traumatic brain injury, are also sequalae of an ischemic insult.     

E-selectin appears in nonischemic tissue during experimental focal cerebral ischemia

BACKGROUND AND PURPOSE: E-selectin participates in leukocyte-endothelial adhesion and the inflammatory processes that follow focal cerebral ischemia and reperfusion. The temporal and topographical patterns of microvascular E-selectin presentation after experimental focal cerebral ischemia are relevant to microvascular reactivity to ischemia. METHODS: The upregulation and fate of E-selectin antigen during 2 hours of middle cerebral artery occlusion (n = 4) and 3 hours of occlusion with reperfusion (1 hour, n = 4; 4 hours, n = 6; 24 hours, n = 6) were evaluated in the nonhuman primate. E-selectin and E:P-selectin immunoreactivities were semiquantitated with the use of computerized light microscopy video imaging and laser confocal microscopy. RESULTS: Three patterns of microvascular E-selectin expression, defined by the antibody E-1E4, were confirmed by complete elimination of E-1E4 binding after incubation with soluble recombinant human E-selectin: (1) Low immunoperoxidase intensity was observed in ischemic microvessels at 2 hours of occlusion extending to 4 hours of reperfusion (E-selectin/laminin = 0.32 +/- 0.10). (2) A significant fraction of ischemic microvessels displayed high-intensity E-selectin signal by 24 hours of reperfusion (0.61 +/- 0.17) compared with control and nonischemic tissues (2P < .003). (3) In the contralateral nonischemic basal ganglia and other nonischemic tissues, low but significant E-selectin levels appeared by 24 hours of reperfusion (2P = .0005). The latter were further confirmed by an E:P-selectin immunoprobe. CONCLUSIONS: E-selectin antigen is distinctively and significantly upregulated in nonhuman primate brain after focal ischemia and reperfusion. The late appearance of E-selectin in nonischemic cerebral tissues suggests stimulation by transferable factors generated during brain injury.     

Glutamate receptor antagonists inhibit calpain-mediated cytoskeletal proteolysis in focal cerebral ischemia

Excitatory amino acids may promote microtubular proteolysis observed in ischemic neuronal degeneration by calcium-mediated activation of calpain, a neutral protease. We tested this hypothesis in an animal model of focal cerebral ischemia without reperfusion. Spontaneously hypertensive rats were treated with 2, 3-dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)quinoxaline (NBQX), a competitive antagonist of the neuronal receptor for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), or cis-4-[phosphono-methyl]-2-piperidine carboxylic acid (CGS 19755), a competitive antagonist of the N-methyl-d-aspartate (NMDA) receptor. After treatment, all animals were subjected to permanent occlusion of the middle cerebral artery for 6 or 24 h. Infarct volumes measured in animals pretreated with CGS 19755 after 24 h of ischemia were significantly smaller than those quantified in ischemic controls. Rats pretreated with NBQX showed partial amelioration of cytoskeletal injury with preserved immunolabeling of microtubule-associated protein 2 (MAP 2) at 6 and 24 h and reduced accumulation of calpain-cleaved spectrin byproducts only at 6 h. Prevention of cytoskeletal damage was more effective after pretreatment with CGS 19755, as shown by retention of MAP 2 immunolabeling and significant restriction of calpain activity at both 6 and 24 h. Preserved immunolabeling of tau protein was observed at 6 and 24 h only in animals pretreated with CGS 19755. Western analysis performed on ischemic cortex taken from controls or rats pretreated with either NBQX or CGS 19755 suggested that loss of tau protein immunoreactivity was caused by dephosphorylation, rather than proteolysis. These results demonstrate a crucial link between excitotoxic neurotransmission, microtubular proteolysis, and neuronal degeneration in focal cerebral ischemia.     

Cerebral vessels express interleukin 1beta after focal cerebral ischemia

Rapid and marked increased levels of expression of interleukin 1beta (IL-1beta) mRNA have been detected in animal models of cerebral ischemia. However, the protein production of IL-1beta and the cellular sources of IL-1beta are largely undefined after cerebral ischemia. In the present study, we have measured the cellular localization of IL-1beta protein in brain tissue from non-ischemic and ischemic mice using immunohistochemistry. Male C57B/6J (n=45) mice were subjected to middle cerebral artery (MCA) occlusion by a clot or a suture. The mice were sacrificed at time points spanning the period from 15 min to 24 h after onset of the MCA occlusion. Non-operated and sham-operated mice were used as control groups. A monoclonal anti-IL-1beta antibody was used to detect IL-1beta. In the non-operated and sham-operated mice, a few IL-1beta immunoreactive cells were detected scattered throughout both hemispheres. IL-1beta immunoreactive cells increased in the ischemic lesion as early as 15 min and peaked at 1 h to 2 h after MCA occlusion. IL-1beta immunoreactivity was detected in the cortex of the contralateral hemisphere 1 h after ischemia. By 24 h after onset of ischemia, IL-1beta immunoreactivity was mainly present adjacent to the ischemic lesion and in the non-ischemic cortex. IL-1beta immunoreactivity was found on endothelial cells and microglia. This study demonstrates an early bilateral expression of IL-1beta on endothelium after MCA occlusion in mice.     

Intraluminal increase of superoxide anion following transient focal cerebral ischemia in rats

OBJECTIVES: We studied the triggering mechanism for neurally mediated syncope. BACKGROUND: Although increased transient sympathetic tone is thought to be necessary for the development of neurally mediated syncope, little is known about the triggering mechanism for neurally mediated syncope. METHODS: Plasma epinephrine (EP) and norepinephrine (NE) levels were assessed in 20 syncope patients during tilt test (80 degrees, 15 min) with and without isoproterenol (ISP, 0.01, 0.02 microg/kg/min). If syncope occurred, propranolol (0.1 mg/kg) was injected. RESULTS: Eight patients experienced syncope during tilting alone, and 9 patients required ISP for syncope. In the negative response without ISP, NE showed a small statistical 1.7-fold increase at end of tilting and EP did not change during tilting. When syncope occurred during tilting alone, a significant 11.7-fold increase in EP at syncope was registered concomitant with a small 2.5-fold increase in NE. When patients experienced syncope during tilting with ISP, a significant 5.0-fold increase in EP at syncope was registered concomitant with a small 1.7-fold increase in NE. In patients without ISP, propranolol did not interrupt syncope. In patients with ISP, six of eight receiving propranolol responded to tilting negatively. CONCLUSIONS: An increase of NE levels may result in inhibition of syncope and an EP surge may be a triggering mechanism for neurally mediated syncope. Comparatively low levels of EP may be enough to induce syncope during tilting with ISP compared with tilting alone. Propranolol is not effective in patients without ISP, but it frequently inhibits syncope in patients with ISP. Propranolol (0.1 mg/kg) may be insufficient to block the actions of high levels of circulating EP.     

Cytosolic redistribution of cytochrome c after transient focal cerebral ischemia in rats

Recent in vitro cell-free studies have shown that cytochrome c release from mitochondria is a critical step in the apoptotic process. The present study examined the expression of cytochrome c protein after transient focal cerebral ischemia in rats, in which apoptosis was assumed to contribute to the expansion of the ischemic lesion. In situ labeling of DNA breaks in frozen sections after 90 minutes of middle cerebral artery (MCA) occlusion showed a significant number of striatal and cortical neurons, which were maximized at 24 hours after ischemia, exhibiting chromatin condensation, nuclear segmentation, and apoptotic bodies. Cytosolic localization of cytochrome c was detected immunohistochemically in the ischemic area as early as 4 hours after 90 minutes of MCA occlusion. Western blot analysis of the cytosolic fraction revealed a strong single 15-kDa band, characteristic of cytochrome c, only in the samples from the ischemic hemisphere. Western blot analysis of the mitochondrial fraction showed a significant amount of mitochondrial cytochrome c in nonischemic brain, which was decreased in ischemic brain 24 hours after ischemia. These results provide the first evidence that cytochrome c is being released from mitochondria to the cytosol after transient focal ischemia. Although further evaluation is necessary to elucidate its correlation with DNA fragmentation, our results suggest the possibility that cytochrome c release may play a role in DNA-damaged neuronal cell death after transient focal cerebral ischemia in rats.     

Regional CBF in apolipoprotein E-deficient and wild type mice during focal cerebral ischemia

Apolipoprotein E-(apoE) deficient mice exhibit hypercholesterolemia, accelerated atherosclerosis and increased infarct size after middle cerebral artery occlusion (MCAO). This study examined whether worsened ischemic outcome is attributable to effects of apoE deficiency on cerebral circulation. Wild type and apoE-deficient mice underwent MCAO and autoradigraphic measurement of cerebral blood flow. Circle of Willis anatomy was examined in non-ischemic animals. Both groups exhibited similar reduction in blood flow. Both groups had 100% incidence of filling of the anterior communicating artery. The posterior communicating artery (PcomA) filled in 70% of wild type and 80% of apoE-deficient mice. Both groups had considerable variability in relative sizes of the PcmA. This study indicates that worsened outcome from MCAO of apoE-deficient mice is not attributable to any detectable vascular effects and offers validity to use of apoE-deficient mice for study of apoE as a factor in cerebral ischemic pathophysiology.     

Fastigial stimulation increases ischemic blood flow and reduces brain damage after focal ischemia

Electrical stimulation of the cerebellar fastigial nucleus (FN) increases CBF and reduces brain damage after focal ischemia. We studied whether FN stimulation "protects" the brain from ischemic damage by increasing blood flow to the ischemic territory. Sprague-Dawley rats were anesthetized (halothane 1-3%) and artificially ventilated through a tracheal cannula inserted transorally. CBF was monitored by a laser-Doppler probe placed over the convexity at a site corresponding to the area spared from infarction by FN stimulation. Arterial pressure (AP), blood gases, and body temperature were controlled, and the electroencephalogram (EEG) was monitored. The stem of the middle cerebral artery (MCA) was occluded. After occlusion, the FN was stimulated for 60 min (100 microA; 50 Hz; 1 s on-1 s off) while AP was maintained at 97 +/- 11 mm Hg (mean +/- SD) by controlled hemorrhage. Rats were then allowed to recover, and infarct volume was determined 24 h later in thionin-stained sections. In unstimulated rats (n = 7), proximal MCA occlusion reduced CBF and the amplitude of the EEG. One day later, these rats had infarcts involving neocortex and striatum. FN stimulation after MCA occlusion (n = 12) enhanced CBF and EEG recovery [61 +/- 34 and 73 +/- 43%, respectively at 60 min; p < 0.05 vs. unstimulated group; analysis of variance (ANOVA)] and reduced the volume of the cortical infarct by 48% (p < 0.05). In contrast, hypercapnia (PCO2 = 64 +/- 4; n = 7) did not affect CBF and EEG recovery or infarct volume (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Intraventricular brain-derived neurotrophic factor reduces infarct size after focal cerebral ischemia in rats

Brain-derived neurotrophic factor (BDNF), acting through the high-affinity receptor tyrosine kinase (TrkB), is widely distributed throughout the central nervous system and displays in vitro trophic effects on a wide range of neuronal cells, including hippocampal, cerebellar, and cortical neurons. In vivo, BDNF rescues motorneurons, hippocampal, and substantia nigral dopaminergic cells from traumatic and toxic brain injury. After transient middle cerebral artery occlusion (MCAO), upregulation of BDNF-mRNA in cortical neurons suggests that BDNF potentially plays a neuroprotective role in focal cerebral ischemia. In the current study, BDNF (2.1 micrograms/d) in vehicle or vehicle alone (controls) was delivered intraventricularly for 8 days, beginning 24 hours before permanent middle cerebral artery occlusion by intraluminal suture in Wistar rats (n = 13 per group). There were no differences in physiological variables recorded during surgery for the two groups. Neurological deficit (0 to 4 scale), which was assessed on a daily basis, improved in BDNF-treated animals compared with controls (P < 0.05; analysis of variance and Scheffe's test). There were no significant differences in weight in BDNF-treated animals and controls during the experiment. After elective killing on day 7 after MCAO, brains underwent 2,3,5-triphenyltetrazolium chloride staining for calculation of the infarct volume and for histology (hematoxylin and eosin and glial fibrillary acid protein). The mean total infarct volume was 83.1 +/- 27.1 mm3 in BDNF-treated animals and 139.2 +/- 56.4 mm3 in controls (mean +/- SD; P < 0.01, unpaired, two-tailed t-test). The cortical infarct volume was 10.8 +/- 7.1 mm3 in BDNF-treated animals and 37.9 +/- 19.8 mm3 in controls (mean +/- SD; P < 0.05; unpaired, two-tailed t-test), whereas ischemic lesion volume in caudoputaminal infarction was not significantly different. These results show that pretreatment with intraventricular BDNF reduces infarct size after focal cerebral ischemia in rats and support the hypothesis of a neuroprotective role for BDNF in stoke.     

Calcitonin gene-related peptide reduces brain injury in a rat model of focal cerebral ischemia

BACKGROUND AND PURPOSE: Calcitonin gene-related peptide is an endogenous vasodilating neuropeptide with a dense concentration in the trigeminocerebrovascular system. It is hypothesized that depletion of this peptide contributes to delayed cerebral ischemia after subarachnoid hemorrhage and that an exogenous supply of calcitonin gene-related peptide will augment ischemic cerebral blood flow and reduce neuronal injury. METHODS: In this study we have investigated the effect of an intravenous infusion of calcitonin gene-related peptide (100 ng/kg per minute), started 1 hour before and continued throughout 4 hours of focal cerebral ischemia, on cerebral blood flow and the volume of brain injury in a rat model of middle cerebral artery occlusion. RESULTS: Calcitonin gene-related peptide produces a significant improvement in ischemic cerebral blood flow (32 +/- 2 compared with 13 +/- 2 mL/100 g per minute in the controls; t = 6.92, P < .0001) with a concomitant reduction in the volume of ischemic brain injury (102 +/- 22 compared with 234 +/- 19 mm3; t = 4.47, P < .001). CONCLUSIONS: These findings lend support for the potential use of this peptide in the prophylactic treatment of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.     

Neuronal damage and plasticity identified by microtubule-associated protein 2, growth-associated protein 43, and cyclin D1 immunoreactivity after focal cerebral ischemia in rats

BACKGROUND AND PURPOSE: An objective of therapeutic intervention after cerebral ischemia is to promote improved functional outcome. Improved outcome may be associated with a reduction of the volume of cerebral infarction and the promotion of cerebral plasticity. In the developing brain, neuronal growth is concomitant with expression of particular proteins, including microtubule-associated protein 2 (MAP-2), growth-associated protein 43 (GAP-43), and cyclin D1. In the present study we measured the expression of select proteins associated with neurite damage and plasticity (MAP-2 and GAP-43) as well as cell cycle (cyclin D1) after induction of focal cerebral ischemia in the rat. METHODS: Brains from rats (n=28) subjected to 2 hours of middle cerebral artery occlusion and 6 hours, 12 hours, and 2, 7, 14, 21, and 28 days (n=4 per time point) of reperfusion and control sham-operated (n=3) and normal (n=2) rats were processed by immunohistochemistry with antibodies raised against MAP-2, GAP-43, and cyclin D1. Double staining of these proteins for cellular colocalization was also performed. RESULTS: Loss of immunoreactivity of both MAP-2 and GAP-43 was observed in most damaged neurons in the ischemic core. In contrast, MAP-2, GAP-43, and cyclin D1 were selectively increased in morphologically intact or altered neurons localized to the ischemic core at an early stage (eg, 6 hours) of reperfusion and in the boundary zone to the ischemic core (penumbra) during longer reperfusion times. CONCLUSIONS: The selective expressions of the neuronal structural proteins (MAP-2 in dendrites and GAP-43 in axons) and the cyclin D1 cell cycle protein in neurons observed in the boundary zone to the ischemic core are suggestive of compensatory and repair mechanisms in ischemia-damaged neurons after transient focal cerebral ischemia.     

Deficiency of intercellular adhesion molecule 1 attenuates microcirculatory disturbance and infarction size in focal cerebral ischemia

Recent evidence has shown crucial roles for cell-adhesion molecules in inflammation-induced rolling, adhesion, and accumulation of neutrophils in tissue. Intercellular adhesion molecule-1 (ICAM-1) is one of these adhesion molecules. Previous studies have shown marked reduction in the size of infarction after focal cerebral ischemia by depletion of granulocytes and administration of the antibody against ICAM-1. In the present study we investigated the role of ICAM-1 in the size of ischemic lesions, accumulation of granulocytes, and microcirculatory compromise in focal cerebral ischemia by using ICAM-1-knockout mice. Ischemic lesions were significantly mitigated in knockout mice after permanent and transient focal ischemia, even though the number of granulocytes in the infarcted tissue was almost the same between knockout and wild-type mice. Depletion of granulocytes further decreased the size of ischemic lesions after transient focal ischemia in ICAM-1-knockout mice. Microcirculation was reduced after focal ischemia, but it was better preserved in the cerebral cortex of knockout mice than that of wild-type mice. The present study demonstrated that ICAM-1 played a role in microcirculatory failure and subsequent development and expansion of infarction after focal cerebral ischemia. However, it is highly unlikely that ICAM-1 played a key role in accumulation of granulocytes after focal cerebral ischemia.     

Neuronal damage following transient cerebral ischemia and its restoration by neural transplant

The middle cerebral artery (mca) was intraluminally occluded for one hour prior to reperfusion in the rat. Neuronal damage as well as motor imbalance were assessed in both acute and chronic stages with or without neural transplant in the striatum. In acute stage, argyrophil III staining demonstrated "collapsed" dark neurons in the ipsilateral striatum, cortex, reticular thalamus, amygdala and sometimes in the hippocampus. They had shrunken somata and corkscrew-like dendrites. In accordance with the appearance of dark neurons, the immunoreactivity for calpain of endogenous inactive form decreased or disappeared in ischemic areas. In chronic stage, ischemic core area (striatum and cortex) got into porencephaly, and animals made rotations following methamphetamine injection. Neural transplant (fetal striatal cells) was made during 2 to 4 weeks after the ischemia. Once the transplant survived and grew in the striatum, the methamphetamine rotations were attenuated. Using mca ischemic model rats we report here pathophysiological processes that lead to neuronal damage and infarct. Neural transplants into these animals brought partial restoration in motor disturbance, offering a valuable information concerning therapeutic possibility.     

Effects of postischemic halothane administration on outcome from transient focal cerebral ischemia in the rat

BACKGROUND: Serologic methods to detect Helicobacter pylori in infants, especially in developing countries, may be limited because of decreased immune response caused by malnutrition. The true prevalence may therefore be underestimated in this age group. Urea breath test is considered to be a good screening method in children but is expensive and therefore is not suitable for screening in developing countries. Simple, inexpensive, and accurate noninvasive methods to detect H. pylori in infants and young children are needed. METHODS: Enzyme immunoassay (EIA) and immunoblot (IB) serologic analyses, 13C-urea breath test (UBT), and immunomagnetic separation--polymerase chain reaction (IMS-PCR) were performed on stool specimens, to detect H. pylori in 68 children between 4 and 24 months of age (mean, 11.5 months) in an endemic area in Bangladesh and the results compared. RESULTS: The occurrence of H. pylori was 57% (n=39) using only UBT, 60% (n=41) using only IMS-PCR, and 78% (n=53) using UBT and IMS-PCR together. The concordance between UBT and IMS-PCR results was 62%. Immunoblot was positive in only 9% (n=6). Results in all 68 children were negative using EIA. DISCUSSION: The prevalence of H. pylori infection in this periurban community and age group was high. Only serologic methods seem to be unsatisfactory for screening of H. pylori infection in infants and may not reflect the true prevalence. Immunomagnetic separation-PCR is a simple and rapid method for detection of H. pylori in stool and is an attractive method for analysis of colonization in infants. However, it may reflect a different stage of disease than UBT. Further studies are needed to clarify this.