Inducible Nitric Oxide Synthase Mediates Hippocampal Caspase-3 Activation in Pneumococcal MeningitisBraun, Johann
doi: 10.1080/00207450802479970pmid: 19229714
Brain damage in bacterial meningitis is still a major problem. More knowledge about the triggers and mechanisms of neuronal damage in bacterial meningitis is needed to improve outcome in bacterial meningitis. The most common bacterial meningitis pathogen—Streptococcus pneumoniae—causes caspase activation and neuronal apoptosis in the hippocampus via its toxins and extensive inflammatory potential. Nitric oxide (NO)—produced by inducible nitric oxide synthase (iNOS)—is a major inflammatory mediator clearly upregulated in the cerebrospinal fluid during pneumococcal meningitis. However, its effects in bacterial meningitis are still controversial. This article demonstrates that genetic inactivation of iNOS results in a marked reduction of caspase-3-mediated neuronal damage in experimental murine pneumococcal meningitis. Protection of hippocampal neurons in iNOS knockout mice was not due to differences in intrathecal growth of S. pneumoniae and must therefore be attributed to differences of host inflammatory mediators. This indicates that NO plays an important role in hippocampal caspase-3 activation during pneumococcal meningitis.
Nestin Positive Cells in the Retina and Spinal Cord of the Sturgeon after HypoxiaFang, Marong; Hu, Zhiying; Li, Yan; Li, Jicheng; Yew, David T.; Ling, Shucai
doi: 10.1080/00207450802324481pmid: 19229715
Sturgeon is an archaic fish which first evolved 100–200 million years ago and has changed very little morphologically since then. In the current study, we are interested in the effects of hypoxia on the retina and spinal cord of this archaic fish. Immunohistochemistry was used to detect the expression pattern of nestin, an intermediate neurofilament, after 10 min and 30 min of hypoxia. Our results showed that nestin-expression in these two neural regions are very different. In the normal retina, nestin was widely distributed throughout the retina while it was absent in the normal spinal cord. However, once the sturgeon was exposed to hypoxic condition, even one of short duration, the pattern of nestin expression was reversed and it is now absent in the hypoxic retina but is present in the hypoxic spinal cord. These results suggest that nestin expression, which is usually associated with glial reactivation, may be further influenced by other undetermined factors in this archaic fish.
Stability of Synchronous Oscillations in a Periodic NetworkOprisan, Sorinel Adrian
doi: 10.1080/00207450802336766pmid: 19229717
We derived a stability criterion for the totally synchronized state of a periodic network of coupled functional units. The periodicity constraint was the key assumption in deriving our circulant matrix-based stability criterion. The functional units were nonlinear discrete dynamical systems. We assumed exponentially decaying coupling strength versus distance in order to reduce the number of control parameters that would have been introduced due to the functional units’ coupling. As a concrete example, we determined the stability domain of the synchronous state for logistic type functional units.
Neuropeptide Y in Rat Spiral Ganglion Neurons and Inner Hair Cells of Organ of Corti and Effects of a Nontraumatic Acoustic StimulationGomide, Vânia C.; Laureano, Maura R.; Silveira, Gilcélio A.; Chadi, Gerson
doi: 10.1080/00207450802330462pmid: 19229719
Neuropeptide Y (NPY) is an important neuromodulator found in central and peripheral neurons. NPY was investigated in the peripheral auditory pathway of conventional housed rats and after nontraumatic sound stimulation in order to localize the molecule and also to describe its response to sound stimulus. Rats from the stimulation experiment were housed in monitored sound-proofed rooms. Stimulated animals received sound stimuli (pure tone bursts of 8 kHz, 50 ms duration presented at a rate of 2 per second) at an intensity of 80 dB sound pressure level for 1 hr per day during 7 days. After euthanizing, rat cochleae were processed for one-color immunohistochemistry. The NPY immunoreactivity was detected in inner hair cells (IHC) and also in pillar and Deiters’ cells of organ of Corti, and in the spiral ganglion putative type I (≥1,009 μm3) and type II (≤225 μm3) neurons. Outer hair cells (OHC) showed light immunoreaction product. Quantitative microdensitometry showed strong and moderate immunoreactions in IHC and spiral ganglion neurons, respectively, without differences among cochlear turns. One week of acoustic stimulation was not able to induce changes in the NPY immunoreactivity intensity in the IHC of cochlea. However, stimulated rats showed an overall increase in the number of putative type I and type II NPY immunoreactive spiral ganglion neurons with strong, moderate, and weak immunolabeling. Localization and responses of NPY to acoustic stimulus suggest an involvement of the neuropeptide in the neuromodulation of afferent transmission in the rat peripheral auditory pathway.
ICTAL Aphasia as Manifestation of Partial Status Epilepticus in a Long-Lasting Misdiagnosed Symptomatic Epilepsy: An Emblematic CaseSperli, F.; Placidi, F.; Izzi, F.; Marciani, M. G.; Floris, R.; Ludovici, A.; Cervellino, A.; Torelli, F.; Romigi, A.
doi: 10.1080/00207450802333714pmid: 19229720
Magnetic Resonance Imaging (MRI) represents the procedure of choice for detection of anatomical lesions in epilepsy. Vascular malformations in central nervous system, such as cavernoma, can cause symptomatic epilepsy. We describe a case of ictal aphasia as manifestation of a partial status epilepticus probably due to a mutual interaction between a recent bleeding cavernoma and a concomitant reduction of antiepileptic treatment in a long-lasting misdiagnosed symptomatic epilepsy. We conclude that MRI is a mandatory diagnostic method to identify structural abnormalities underlying epilepsy in all patients affected by recurrent focal seizures independent of the duration of epilepsy.
A Forty-Five Year Follow-Up EEG Study of Qigong PracticeQin, Zhen; Jin, Yi; Lin, Shin; Hermanowicz, Neal S.
doi: 10.1080/00207450802325520pmid: 19229721
A follow-up EEG study was conducted on a subject with 50 years of experiences in Qigong. Resting EEG at present showed frontally dominant alpha-1 as compared to occipitally dominant alpha-2 described in 1962. During the Qigong practice alph-1 enhanced quickly and became far more prominent than 50 years ago. Compared with baseline, these activities remained to be higher at rest after the Qigong practice. These results suggest that extended practice in meditation may change the EEG pattern and its underlying neurophysiology. It remains to be explored as to what biological significance and clinical relevance do these physiological changes might mean.
A Cognitive Neuropsychological Examination of the Das-Naglieri Cognitive Assessment System Subtests: A Report of Three Stroke Cases Studied Longitudinally During RecoveryMccrea, Simon M.
doi: 10.1080/00207450802335701pmid: 19229722
In this study three patients with unilateral focalized stroke lesions were examined longitudinally on the CAS subtests at 1 month and 6 months postinfarct such that each patient functioned as baseline. Patient 1 with a left temporal pole lesion had a severe syntactic comprehension deficit on Sentence Questions. Patient 2 had a rare right anterior cerebral artery (ACA) aneurysm culminating in a classical orbitofrontal syndrome and impairments on Expressive Attention, Word Series as well as a previously undescribed praxis-based figure ground reversal phenomenon on Figure Memory. Patient 3 suffered a right frontoparietal lesion with resulting representational as well as elements of motor neglect and impairments on Matching Numbers, Number Detection, and Receptive Attention. The three patient's lesions were all entirely consistent with the nature of cognitive neuropsychological symptoms suggesting that the CAS subtests are not only unique but also sensitive and specific to focalized cortical lesions.
Obsessive-Compulsive Personality Traits: Compensatory Response to Executive Function Deficit?Aycicegi-Dinn, Ayse; Dinn, Wayne M.; Caldwell-Harris, Catherine L.
doi: 10.1080/00207450802543783pmid: 19229723
Obsessive-compulsive personality traits (OCPTs) may be associated with cognitive disorganization (i.e., executive control deficits). That is, individuals presenting with pronounced OCPTs may rigidly adhere to rules and procedure in an attempt to compensate for cognitive disorganization. We predicted that individuals presenting with OCPTs would demonstrate cognitive disorganization during neurocognitive task performance and would display working memory deficits. To test this hypothesis, we identified a group of university students demonstrating pronounced OCPTs and a comparison group, and administered the Rey-Osterrieth Complex Figure Test (ROCFT). Self-report measures of OCPTs, classical OCD, and depressive symptoms were administered. Students presenting with pronounced OCPTs exhibited performance deficits on the ROCFT. They obtained significantly lower copy organization scores and displayed a subtle visuospatial working memory deficit. Performance deficits on a nonverbal measure of executive control and working memory were related to OCPTs, but were not associated with classic OCD symptoms. Our findings lend support to the contention that specific OCPTs may represent, at least in part, compensatory tactics that evolve in response to executive control deficits.