Instrumental role of Na+ and Ca2+ influx via Na+/K+ adenosine triphosphatase (Na+/K+-ATPase) and Na+/Ca2+ exchanger 1 (NCX1) is examined in the N-Methyl-D-aspartate (NMDA) receptor-mediated pathogenesis of penumbra after focal cerebral ischemia. An experimental model of 3, 6, and 24 h focal cerebral ischemia by permanent occlusion of middle cerebral artery was developed in rats. The changes in protein expression of Na+/K+-ATPase and NCX1 as well as functional subunits of NMDA receptor 2A and 2B (NR2A and NR2B) in the penumbra were assessed using by quantitative immunoblottings. The most prominent changes of Na+/K+-ATPase (78+/-6%, n=4, *P<0.05) and NCX1 (144+/-2%, n=4, *P<0.05) in the penumbra were developed 24 h after focal cerebral ischemia. The expression of NR2A in the penumbra was significantly increased (153+/-9%, n=4, *P<0.05) whereas the expression of NR2B was significantly decreased (37+/-2%, n=4, *P<0.05) as compared with sham-operated controls 3 h after focal cerebral ischemia. However, the expression of NR2A and NR2B in the penumbra was reversed 24 h after focal cerebral ischemia (NR2A: 40+/-7%; NR2B: 120+/-16%, n=4, *P<0.05). Moreover, the decreased expression of neuronal nuclei (NeuN) in the penumbra was most prominent than that of glial fibrillary acidic protein (GFAP) 24 h after focal cerebral ischemia. These findings imply that intracellular Na+ accumulation via decreased Na+/K+-ATPase exacerbate the Ca2+ overload cooperated by the increased NCX1 and NR2B-containing NMDA receptor which may play an important role in the pathogenesis of the penumbra.
Adenosine Triphosphatases ; Animals ; Brain ; Brain Ischemia ; Glial Fibrillary Acidic Protein ; Glutamic Acid ; Immunoblotting ; Middle Cerebral Artery ; Models, Theoretical ; N-Methylaspartate ; Neurons ; Rats ; Receptors, N-Methyl-D-Aspartate

In this study, expressions of aquaporin (AQP) 1, AQP4, endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor in blood-cerebrospinal fluid (CSF) barrier and blood-brain barrier (BBB) are examined in rat choroid plexus and peri-infarcted hippocampal formation (HF) following systemic hyponatremia (SH) and permanent middle cerebral artery occlusion (pMCAO). These events are thought to cause the development of hydrocephalic and vasogenic edemas. The importance of CSF overproduction and intact blood-CSF barrier during hydrocephalic edema formation is demonstrated by the high expression of AQP1 (329.86+/-10.2%, n=4 , P<0.01) and trapped plasma immunoglobulin G (IgG) in choroid plexus epithelium after 24 hours of SH. However, the increased eNOS expression in peri-infarcted HF (130+/-3%, n=4, P<0.01) and extravasation of plasma IgG into the extravascular compartment after 24 hours of pMCAO suggest that increased microvascular permeability, probably due to elevated levels of nitric oxide, leads to development of vasogenic brain edema via BBB breakdown. Based on these findings, the authors suggest that modulation of different protein expression, dependent on the type of brain edema, is required for primary (pMCAO) and secondary (SH) brain injuries to attenuate brain edema and neuronal degeneration.
Animals ; Aquaporin 1 ; Blood-Brain Barrier ; Brain Edema ; Brain Injuries ; Capillary Permeability ; Choroid Plexus ; Edema ; Epithelium ; Hippocampus ; Hyponatremia ; Immunoglobulin G ; Infarction, Middle Cerebral Artery ; Neurons ; Nitric Oxide ; Nitric Oxide Synthase Type III ; Plasma ; Proteins ; Rats ; Vascular Endothelial Growth Factor A

A central challenge in ischemia-induced neuronal death research is understanding the mechanisms by which apoptotic or necrotic cascades are initiated and affected. We tested potential roles for AMPA and NMDA receptor protein levels and activation of calpain, caspase-3 in the hippocampus at times after transient global ischemia when detectable necrotic or apoptotic cell damage was observed by neurofilament 200 (NF200) degradation, TUNEL, and H & E. We determined that the decrease in the AMPA receptor subunit, GluR2, in response to the transient global ischemia plays a major role in triggering the neuronal cell death in hippocampus. We also examined potential roles for calpain and caspase-3 in ischemic cell death and found that (1) calpain is activated at a time following caspase-3 activation and paralleled degradation of NR2A, NR2B, and GluR2 and irreversible necrotic neuronal changes, (2) caspase-3 is has their maximal expression at the time of highest apoptosis, (3) the NF200 degradation, one of the neuronal deathinducing factors was correlated well with the calpain activation and necrotic changes in the hippocampal CA1 neurons. These results suggest that the significant degradation of GluR2 subunits of AMPA receptor and calpain activation are possibly involved in NF 200 degradation-mediated necrotic hippocampal cell death after transient global ischemia.
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid* ; Animals ; Apoptosis ; Calpain* ; Caspase 3* ; Cell Death* ; Hippocampus* ; In Situ Nick-End Labeling ; Ischemia* ; N-Methylaspartate ; Neurons* ; Rats* ; Receptors, AMPA

Paralimbic association area in the temporal pole is situated between sensory association areas and the limbic regions and has direct connections with these areas and the ventral striatum. Corticostriatal connections of paralimbic association area in the temporal pole were studied with particular emphasis on specific projections of the ventral striatum to identify different contributions to the functional outcome of the ventral striatum. Retrograde tracers were injected into the five different regions of the ventral striatum such as the ventromedial caudate nucleus, ventral shell, central shell, dorsal core of the nucleus accumbens (NA), and ventrolateral putamen to identify the labeled cells of origin. Present results indicate that the temporal pole has specifically dense projections to the ventral shell of NA. This differential pattern of corticostriatal connectivity suggests that ventral shell region of ventral striatum is preferentially involved in the convergence of sensory and limbic stimulus to motivational and emotional states.
Basal Ganglia ; Caudate Nucleus ; Nucleus Accumbens ; Primates* ; Putamen

The expression of aquaporin-4 (AQP4) protein, bi-directional water channel, in the blood-brain barrier of the hippocampal formation (HF) was studied in the rat to determine the role of AQP4 in the pathophysiology of systemic hyponatremia. Systemic hyponatremia was induced by coadministration of 30 ml (~12% body weight) dextrose solution (140 mM) intraperitoneally and a 3-microg subcutaneous dose of 1-deamino-8-D-arginine vasopressin (dDAVP). Two and six hours after the drug administration, there were significant reductions in the serum osmolarity (252+/-5.1 and 252+/-6.4 mOsm/L) and in Na+/- concentration (117+/-1.7 and 97.2 mM) from the control values (296+/-5.2 mOsm/L, 140+/-4.7 mM). Brain injury in the HF and the expression of AQP4 were determined by using TUNEL, immunohistochemistry and quantitative immunoblotting. TUNEL revealed apoptotic cell death in the dentate gyrus (DG), presumably resulting from brain edema and a subsequent elevation of intracranial pressure after 2 h of systemic hyponatremia. However, AQP4 expression was decreased by 82%+/-6% after 2 h of systemic hyponatremia and then normalized after 6 h (108%+/-9%) compared with that of the control. Therefore, apoptotic cell death in the DG from brain swelling in this systemic hyponatremic model is likely associated with decrease of excessive brain water elimination because reincreased AQP4 expression/function accelerates the elimination of apoptotic cells from the DG.
Animals ; Apoptosis ; Aquaporin 4* ; Blood-Brain Barrier ; Brain ; Brain Edema ; Brain Injuries ; Cell Death ; Deamino Arginine Vasopressin ; Dentate Gyrus ; Glucose ; Hippocampus* ; Hyponatremia* ; Immunoblotting ; Immunohistochemistry ; In Situ Nick-End Labeling ; Intracranial Pressure ; Osmolar Concentration ; Rats

It has been known that granule neurons of the dentate gyrus (DG) are born in adulthood as well as during development. Apoptotic cell death also occurs normally throughout the life of the rat brain. The present study was designed to determine the effect of transient global ischemia on the apoptosis and/or neurogenesis of granule cells in the dentate gyrus. TUNEL study revealed that the ischemia produced an significant increase in apoptosis mainly in the granular zone (GZ) of the DG. The percentage of TUNEL-positive cells in the DG was maximal (37.3+/-2.5%) 8 hr after ischemia and declined thereafter. However, immunocytochemical studies showed that there was an increase in neurogenesis mainly in the subgranular zone (SGZ) although the induction of neurogenesis took longer than the apoptosis. As a neurogenesis marker, proliferating cell nuclear antigen (PCNA)-positive cells, possibly progenitor cells, were significantly increased by 34.1+/-2.2%(n=3, p<0.05) mainly in the dentate SGZ 4 days after ischemia. In addition, the gradual increase in Bcl-2 expression was only paralleled with the neurogenesis in the SGZ, but not with the apoptosis in the GZ of the DG. The expression level of Bcl-2 in the SGZ was increased significantly (optical density 43.7+/-3.4; n = 3, p<0.05) 4 days after the ischemic insult. Furthermore, the ischemia-induced neurogenesis in the SGZ was also indirectly supported by the observation that the expression of synapsin-alpha was significantly increased (176%; n=3 p<0.05) in the CA3 region 4 days after the ischemia. Taken together, these results strongly suggest that the transient global ischemia induces the apoptosis in the GZ, whereas the cell proliferation in the SCZ of the DG. In situ hybridization using the antisense probes to the NR2A and NR2B subunits of NMDA receptors revealed that the ischemia produced a more profound effect on the mRNA expression of NR2A (61.9% reduction) than NR2B (20.5% reduction). Thus, we also suggest a possibility that ischemia could induce the neurogenesis in the SGZ of the DG through downregulation of the number of functional NMDA receptors.
Animals ; Antisense Elements (Genetics) ; Apoptosis* ; Brain ; Cell Death ; Cell Proliferation ; Dentate Gyrus* ; Down-Regulation ; In Situ Hybridization ; In Situ Nick-End Labeling ; Ischemia* ; Neurogenesis* ; Neurons ; Proliferating Cell Nuclear Antigen ; Rats* ; Receptors, N-Methyl-D-Aspartate ; RNA, Messenger ; Stem Cells

Background: In pancreatic cancer surgery, anatomical understanding of lymph node metastases is required. Distinguishing lymph nodes in computed tomography or magnetic resonance imaging is challenging for novice doctors and medical students because of their small size and similar color to surrounding tissues. This study aimed to enhance our understanding of the clinical anatomy of lymph node stations relevant to pancreatic cancer using newly sectioned images of a cadaver with true color and high resolution and their three-dimensional (3D) models. Methods: An 88-year-old female cadaver who died of pancreatic cancer was serially sectioned.Among the sectioned images of the whole body (0.05 mm-sized pixel, 48 bits color), images of the abdomen were selected, and examined to identify lymph nodes and nearby structures.34 structures (9 in digestive system; 1 in urinary system; 2 in cardiovascular system; 22 in lymphatic system) were segmented on the sectioned images. Based on the sectioned and segmented images, volume and surface models were produced. Results: Among the known 28 lymph node stations, 21 stations were identified through location, size, and color of normal and abnormal structures in the sectioned images and 3D models. Two near the splenic artery could not be separated from the cancer tissue, and the remaining five were not clearly identified. In the surface models, the shape and location of lymph node stations could be confirmed with nearby structures. Conclusion The lymph node stations relevant to pancreatic cancer can be anatomically understood by using the sectioned images and 3D models which contain true color and high resolution.

Brain edema, the infiltration and accumulation of excess fluid causing an increase in brain tissue volume, often leads to a rise in intracranial pressure (ICP) and is a key contributor to the morbidity and mortality associated with brain injury. We examined the mechanisms for vasogenic brain edema produced by focal cerebral ischemia. To test the mechanisms underlying vasogenic brain edema, we compared the expression of endothelial nitric oxide synthase (eNOS) and aquaporin-4 (AQP4) in the penumbra of brain tissues after focal cerebral ischemia. The expression of eNOS and AQP4 in the ischemic penumbra was determined by quantitative immunoblot analysis. In focal cerebral ischemia, eNOS expression increased significantly to 129%+/-6% of the value for sham-operated controls (n=4, P<0.01). In contrast, AQP4 expression decreased significantly to 52%+/-3% of the value for shamoperated controls (n=4, P<0.01). These findings suggest that the expression of eNOS and AQP4 in the focal cerebral ischemia may play different roles in the formation of vasogenic brain edema. Additionally, a larger decrease in the neuronal nuclei (NeuN) (39%+/-7% of the value in sham-operated controls; n=4, P<0.01) than the decrease in glial fibrillary acidic protein (GFAP) (53%+/-14% of sham-operated controls; n=4, P<0.01) in the penumbra after focal cerebral ischemia suggests that the neurons are more susceptible to ischemic injury than are the astrocytes.
Astrocytes ; Brain ; Brain Edema ; Brain Injuries ; Brain Ischemia ; Edema ; Glial Fibrillary Acidic Protein ; Intracranial Pressure ; Neurons ; Nitric Oxide Synthase Type III

Objective: We aimed to share our experience studying the effects and stability of intravenous propafenone in patients with atrial fibrillation (AF). Methods: This single-center retrospective study evaluated the baseline and clinical characteristics of patients with atrial fibrillation admitted to the emergency room and treated with propafenone between December 2018 and May 2019;patients were analyzed according to new onset AF and chronic AF groups. Results: Among 24 patients included in the present study, 15 patients were in the new onset AF group while nine were in the chronic AF group. Cardioversion was successful in 15 (73.3%) in the new onset AF group and two (22.2%) in the chronic AF group (P=0.033). The time to cardioversion was relatively short in patients in the new onset AF group (81 minutes vs. 122 minutes, log-rank, P=0.019). Recurrence of AF at 30 days was two (17.2%) in the new onset AF group and 0 (0.0%) in the chronic AF group. No major adverse event was observed except each hypotension in the new onset and chronic AF groups. Conclusion Sinus conversion of propafenone in patients with AF occurring within 48 hours in the emergency room may be considered.

The organization of the striatal projection fibers from the hippocampal formation (HF) was studied in the monkey with particular emphasis on specific projections of the ventral striatum. Retrograde tracers were injected into the five different regions of the ventral striatum such as the ventromedial caudate nucleus, ventral shell, central shell, and dorsal core of the nucleus accumbens (NA), and ventrolateral putamen. The ventromedial caudate nucleus and the shell of the NA received dense projections from the HF. Although the ventromedial caudate nucleus and the shell of the NA are both innervated by the HF, the shell receives the larger of these projections. This suggests that the HF is more strongly connected with the shell of the NA than with the ventromedial caudate nucleus. There are no differences between the ventral shell and central shell of the NA. Labeled neurons were mainly observed in the rostral parts of the dorsomedial CA1 and adjacent subicular complex (prosubiculum, subiculum, presubiculum, and parasubiculum) of the HF. These results suggest that the shell of the NA is the main converging site receiving hippocampal projections primarily related to integrating visuospatial and limbic information.
Basal Ganglia* ; Caudate Nucleus ; Haplorhini ; Hippocampus ; Neurons ; Nucleus Accumbens ; Primates* ; Putamen