Jul
08
2009
0

Primary brain T-cell lymphoma of the lymphoblastic type presenting as altered mental status.

The authors present a case of a 56-year-old man with altered mental status. Magnetic resonance imaging (MRI) of the brain revealed non-enhancing abnormalities on T2 and FLAIR imaging in the brainstem, cerebellum, and cerebrum. Immunohistochemisty demonstrated precursor T-cell lymphoblastic lymphoma. After treatment with methotrexate, he improved clinically without focal sensorimotor deficits and with improving orientation. MRI showed almost complete resolution of brainstem and cerebral lesions. To the authors’ knowledge, there are only five previous reports of primary central nervous system T-cell lymphoblastic lymphoma. Since treatable, it deserves consideration in patients with altered mental status and imaging abnormalities that include diffuse, non-enhancing changes with increased signal on T2-weighted images.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

Activity of the 5-HT1A receptor is involved in the alteration of glucocorticoid receptor in hippocampus and corticotropin-releasing factor in hypothalamus in SPS rats.

Rats exposed to single-prolonged stress (SPS) showed enhanced inhibition of the hypothalamic-pituitary-adrenal (HPA) system and alteration in the glucocorticoid/mineralocorticoid receptor. Dysfuntion of the HPA axis is one of the core neuroendocrine abnormalities of post-traumatic stress disorder (PTSD). Serotonergic receptor, glucocorticoid receptor (GR) and corticotropin-releasing factor (CRF) have been proposed to play major roles in dysfuntion of the HPA axis. However, the precise molecular mechanism is unknown. In this study, we investigated the relationships between the changes of GR in hippocampus as well as CRF in hypothalamus and the activity of 5-HT1A receptor in SPS rats. We exposed rats to SPS with or without prior treatment with WAY100635 (the 5-HT1A receptor antagonist), and observed behavioral changes, GR levels in the hippocampus and CRF levels in the hypothalamus by immunohistochemistry, Western blotting and RT-PCR seven days after SPS. Our results demonstrate that SPS increases expression of GR and CRF, which were partially inhibited by WAY-100635.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

Facial emotion recognition in bipolar disorder: a critical review.

OBJECTIVE: Literature review of the controlled studies in the last 18 years in emotion recognition deficits in bipolar disorder. METHOD: A bibliographical research of controlled studies with samples larger than 10 participants from 1990 to June 2008 was completed in Medline, Lilacs, PubMed and ISI. Thirty-two papers were evaluated. RESULTS: Euthymic bipolar disorder presented impairment in recognizing disgust and fear. Manic BD showed difficult to recognize fearful and sad faces. Pediatric bipolar disorder patients and children at risk presented impairment in their capacity to recognize emotions in adults and children faces. Bipolar disorder patients were more accurate in recognizing facial emotions than schizophrenic patients. DISCUSSION: Bipolar disorder patients present impaired recognition of disgust, fear and sadness that can be partially attributed to mood-state. In mania, they have difficult to recognize fear and disgust. Bipolar disorder patients were more accurate in recognizing emotions than depressive and schizophrenic patients. Bipolar disorder children present a tendency to misjudge extreme facial expressions as being moderate or mild in intensity. CONCLUSION: Affective and cognitive deficits in bipolar disorder vary according to the mood states. Follow-up studies re-testing bipolar disorder patients after recovery are needed in order to investigate if these abnormalities reflect a state or trait marker and can be considered an endophenotype. Future studies should aim at standardizing task and designs.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

A pox on the mind: Cognitive processing of physical disfigurement.

The unfavorable treatment of people with physical disfigurements is well-documented, yet little is known about basic perceptual and cognitive responses to disfigurement. Here, we identify a specialized pattern of cognitive processing consistent with the hypothesis that disfigurements act as heuristic cues to contagious disease. Disfigurements are often invariant across time and difficult to conceal, and thus observers can detect the presence of the (perceived) contagion cue without necessarily remembering the particular individual bearing that cue. Indeed, despite the fact that disfigured faces were especially likely to hold attention (Study 1), disfigured individuals were often confused with one another and thus not well remembered later (Study 2). We discuss the implications of our results for stigmatization of people with and without physical abnormalities and suggest the possibility that cognitive mechanisms for processing social information may be functionally tuned to the variant nature of important cues.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

Mitochondrial fission factor Drp1 is essential for embryonic development and synapse formation in mice.

Mitochondrial morphology is dynamically controlled by a balance between fusion and fission. The physiological importance of mitochondrial fission in vertebrates is less clearly defined than that of mitochondrial fusion. Here we show that mice lacking the mitochondrial fission GTPase Drp1 have developmental abnormalities, particularly in the forebrain, and die after embryonic day 12.5. Neural cell-specific (NS) Drp1(-/-) mice die shortly after birth as a result of brain hypoplasia with apoptosis. Primary culture of NS-Drp1(-/-) mouse forebrain showed a decreased number of neurites and defective synapse formation, thought to be due to aggregated mitochondria that failed to distribute properly within the cell processes. These defects were reflected by abnormal forebrain development and highlight the importance of Drp1-dependent mitochondrial fission within highly polarized cells such as neurons. Moreover, Drp1(-/-) murine embryonic fibroblasts and embryonic stem cells revealed that Drp1 is required for a normal rate of cytochrome c release and caspase activation during apoptosis, although mitochondrial outer membrane permeabilization, as examined by the release of Smac/Diablo and Tim8a, may occur independently of Drp1 activity.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

Hypophosphataemia: an easy strategy for diagnosis and treatment in HIV patients.

Because HIV infection has become a chronic disease, it is crucial that metabolic complications secondary to HIV infection or prolonged therapy be diagnosed and managed appropriately over time. Therefore the optimal follow-up becomes complex and time consuming. Our review aimed to provide physicians in charge of HIV-infected patients with key data helping them to diagnose and understand hypophosphataemia in HIV patients. Hypophosphataemia is frequent and sometimes secondary to renal phosphate wasting. It is very rarely a component of a complex proximal tubular disorder, such as Fanconi syndrome. When isolated, hypophosphataemia is easy to rule out and treat. In rare cases, prolonged hypophosphataemia, when related to renal phosphate wasting and tubular dysfunction, might have potential consequences on bone outcome, however, more studies are needed. HIV infection by itself might be a risk factor for bone metabolism abnormalities; antiretroviral drugs might also be involved. Therefore, it seems valuable for patients that the minimal screening should be performed routinely, in order to prevent long-term disabilities.

Written by admin in: Ischemic Brain Damage |
Jul
08
2009
0

Increase in end-systolic volume after exercise independently predicts mortality in patients with coronary heart disease: data from the Heart and Soul Study.

Aims The predictive value of changes in global left ventricular (LV) size after exercise has not been studied. Left ventricular end-systolic volume (ESV) is a relatively load-independent echocardiographic marker of contractility that is easily measured. We investigated the role of the change in ESV at rest and after peak exercise on mortality among patients with stable coronary heart disease (CHD). Methods and results We performed exercise treadmill testing with stress echocardiography in 934 ambulatory subjects with CHD. End-systolic volume was measured immediately before and after exercise using 2D echocardiography. We defined ESV reversal as an increase in ESV after exercise, and we examined the association of ESV reversal with all-cause mortality during a median follow-up of 3.92 years. Of the 934 participants, 199 (21%) had ESV reversal. At the end of follow-up, mortality was higher among participants with ESV reversal than those without (26 vs. 11%; P < 0.001). After adjustment for clinical covariates, ESV reversal remained predictive of all-cause mortality (HR 2.0; 95% CI 1.4-2.9; P = 0.001). The association of ESV reversal with mortality also persisted after adjustment for exercise-induced wall-motion abnormalities (HR 1.7; 95% CI 1.1-2.3, P = 0.006). To determine if the effect of ESV reversal was independent from other echocardiographic measurements, we created a separate model adjusting for resting LV ejection fraction, ESV, end-diastolic volume, and LV mass. End-systolic volume reversal was the only significant predictor of mortality in this model (HR 2.1, 95% CI 1.4-3.0, P < 0.001). Conclusion End-systolic volume reversal is a novel parameter that independently predicts mortality in patients with CHD undergoing exercise treadmill echocardiography, even after adjustment for a wide range of clinical, echocardiographic, and treadmill exercise variables. Because measurement of ESV is simple, reproducible, and requires no additional imaging views, identification of ESV reversal during exercise echocardiography can provide useful complementary information for risk stratification.

Written by admin in: Ischemic Brain Damage |
Jul
06
2009
0

Rotenone and Paraquat do not Directly Activate Microglia or Induce Inflammatory Cytokine Release.

Both epidemiological and pathological data suggest an inflammatory response including microglia activation and neuro-inflammation in the Parkinsonian brain. Treatments with lipopolysacchride (LPS), rotenone and paraquat have been used as models for Parkinson’s disease, as they cause dopaminergic neuron degeneration in culture and in animals. Recent studies have suggested that rotenone and paraquat induce neuro-inflammation, however, it is not known if they can directly activate microglia. Here, we use primary cultured microglia to address this question. Microglia activation was analyzed by morphological changes and release of nitric oxide and inflammatory cytokines. Treatment with LPS was used as a positive control. While LPS induced morphological changes characteristic of microglial activation and release of nitric oxide and inflammatory cytokines, rotenone and paraquat did not. Our results suggest that paraquat and rotenone do not act directly on microglia and that neuro-inflammation and microglial activation in animals treated with these agents is likely non-cell autonomous, and may occur as a result of dopaminergic neuron damage or factors released by neurons and other cells.

Written by admin in: Brain Damage |
Jul
06
2009
0

Loss of astrocytic glutamate transporters in Wernicke encephalopathy.

Wernicke encephalopathy (WE), a neurological disorder caused by thiamine deficiency (TD), is characterized by structural damage in brain regions that include the thalamus and cerebral cortex. The basis for these lesions is unclear, but may involve a disturbance of glutamatergic neurotransmission. We have therefore investigated levels of the astrocytic glutamate transporters EAAT1 and EAAT2 in order to evaluate their role in the pathophysiology of this disorder. Histological assessment of the frontal cortex revealed a significant loss of neurons in neuropathologically confirmed cases of WE compared with age-matched controls, concomitant with decreases in alpha-internexin and synaptophysin protein content of 67 and 52% by immunoblotting. EAAT2 levels were diminished by 71% in WE, with levels of EAAT1 also reduced by 62%. Loss of both transporter sites was confirmed by immunohistochemical methods. Development of TD in rats caused a profound loss of EAAT1 and EAAT2 in the thalamus accompanied by decreases in other astrocyte-specific proteins. Treatment of TD rats with N-acetylcysteine prevented the downregulation of EAAT2 in the medial thalamus, and ameliorated the loss of several other astrocyte proteins, concomitant with increased neuronal survival. Our results suggest that (1) loss of EAAT1 and EAAT2 glutamate transporters is associated with structural damage to the frontal cortex in patients with WE, (2) oxidative stress plays an important role in this process, and (3) TD has a profound effect on the functional integrity of astrocytes. Based on these findings, we recommend that early treatment using a combination of thiamine AND antioxidant approaches should be an important consideration in cases of WE. (c) 2009 Wiley-Liss, Inc.

Written by admin in: Brain Damage |
Jul
06
2009
0

Sodium channelopathy induced by mild axonal trauma worsens outcome after a repeat injury.

There is great concern that one mild traumatic brain injury (mTBI) predisposes individuals to an exacerbated response with a subsequent mTBI. Although no mechanism has been identified, mounting evidence suggests traumatic axonal injury (TAI) plays a role in this process. By using a cell culture system, a threshold of mild TAI was found where dynamic stretch of cortical axons at strains lower than 5% induced no overt pathological changes. However, the axons were found to display an increased expression of sodium channels (NaChs) by 24 hr. After a second, identical mild injury, pathologic increases in [Ca(2+)](i) were observed, leading to axon degeneration. The central role of NaChs in this response was demonstrated by blocking NaChs with tetrodotoxin prior to the second injury, which completely abolished postinjury increases in [Ca(2+)](i). These data suggest that mild TAI induces a form of sodium channelopathy on axons that greatly exaggerates the pathophysiologic response to subsequent mild injuries. (c) 2009 Wiley-Liss, Inc.

Written by admin in: Brain Damage |

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