Publications by authors named "Vikram Puvenna"

Background: S100B is an astrocytic protein that enters the blood stream when there is disruption of the blood-brain barrier (BBB). Over time, antibodies against S100B develop in the sera of patients who experience persistent or repeated BBB disruptions. We explored the use of serum S100B protein and S100B autoantibodies for the detection of brain metastasis in patients with lung cancer.

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Repetitive traumatic brain injury (rTBI) is one of the major risk factors for the abnormal deposition of phosphorylated tau (PT) in the brain and chronic traumatic encephalopathy (CTE). CTE and temporal lobe epilepsy (TLE) affect the limbic system, but no comparative studies on PT distribution in TLE and CTE are available. It is also unclear whether PT pathology results from repeated head hits (rTBI).

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Diabetic ketoacidosis (DKA) frequently causes subtle brain injuries in children. Rarely, these injuries can be severe and life threatening. The physiological processes leading to brain injury during DKA are poorly understood.

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S100B is a reporter of blood-brain barrier (BBB) integrity which appears in blood when the BBB is breached. Circulating S100B derives from either extracranial sources or release into circulation by normal fluctuations in BBB integrity or pathologic BBB disruption (BBBD). Elevated S100B matches the clinical presence of indices of BBBD (gadolinium enhancement or albumin coefficient).

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The impact of sub-concussive head hits (sub-CHIs) has been recently investigated in American football players, a population at risk for varying degrees of post-traumatic sequelae. Results show how sub-CHIs in athletes translate in serum as the appearance of reporters of blood-brain barrier disruption (BBBD), how the number and severity of sub-CHIs correlate with elevations of putative markers of brain injury is unknown. Serum brain injury markers such as UCH-L1 depend on BBBD.

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Purpose: Brain drug bioavailability is regulated by the blood-brain barrier (BBB). It was recently suggested that cytochrome P450 (CYP) enzymes could act in concert with multidrug transporter proteins to regulate drug penetration and distribution into the diseased brain. The possibility that phase II metabolic enzymes could be expressed in the epileptic brain has been not evaluated.

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The acknowledgement of risks for traumatic brain injury in American football players has prompted studies for sideline concussion diagnosis and testing for neurological deficits. While concussions are recognized etiological factors for a spectrum of neurological sequelae, the consequences of sub-concussive events are unclear. We tested the hypothesis that blood-brain barrier disruption (BBBD) and the accompanying surge of the astrocytic protein S100B in blood may cause an immune response associated with production of auto-antibodies.

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Purpose: A link between seizure susceptibility, blood-brain barrier (BBB) failure, and the activation of peripheral white blood cells has been recently proposed. However, the molecular players involved in this cascade of events are unknown. We tested the hypothesis that immunosupression by splenectomy or lack of perforin, a downstream factor of natural killer (NK) and cytotoxic T cells, could reduce seizure onset.

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Background: One of the most important and often neglected physiological stimuli contributing to the differentiation of vascular endothelial cells (ECs) into a blood-brain barrier (BBB) phenotype is shear stress (SS). With the use of a well established humanized dynamic in vitro BBB model and cDNA microarrays, we have profiled the effect of SS in the induction/suppression of ECs genes and related functions.

Results: Specifically, we found a significant upregulation of tight and adherens junctions proteins and genes.

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Drug penetration into the central nervous system (CNS) is controlled by the blood-brain barrier (BBB). Even though a number of strategies to circumvent the BBB and to improve drug access have been developed, drug resistance in CNS diseases remains an unmet clinical problem. We here review the mechanisms by which a healthy or pathological BBB influences drug distribution in the brain, with emphasis on the role of P450 metabolic enzymes and multi-drug transporter (MDT) proteins.

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A wind of change characterizes epilepsy research efforts. The traditional approach, based on a neurocentric view of seizure generation, promoted understanding of the neuronal mechanisms of seizures; this resulted in the development of potent anti-epileptic drugs (AEDs). The fact that a significant number of individuals with epilepsy still fail to respond to available AEDs restates the need for an alternative approach.

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Targeting pro-inflammatory events to reduce seizures is gaining momentum. Experimentally, antagonism of inflammatory processes and of blood-brain barrier (BBB) damage has been demonstrated to be beneficial in reducing status epilepticus (SE). Clinically, a role of inflammation in the pathophysiology of drug resistant epilepsies is suspected.

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Recent evidence has indicated that active and passive cigarette smoking are associated, in a dose-dependent manner, with dysfunction of normal endothelial physiology. Tobacco smoke (TS) may predispose individuals to atherogenic and thrombotic problems, significantly increasing the risk for ischemic manifestations such as acute coronary syndrome and stroke. Despite the strong evidence for an association between smoking and vascular impairment, the impact of TS exposure on the blood-brain barrier (BBB) has only been marginally addressed.

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Purpose: Compelling evidence supports the presence of P450 enzymes (CYPs) in the central nervous system (CNS). However, little information is available on the localization and function of CYPs in the drug-resistant epileptic brain. We have evaluated the pattern of expression of the specific enzyme CYP3A4 and studied its co-localization with MDR1.

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