Publications by authors named "Pettegrew J"

Background: Anterior cruciate ligament (ACL) injuries are devastating injuries for athletes. Prior studies have shown increased ACL injury rates on non-natural surfaces versus natural grass in several sports. The purpose of this study is to calculate the prevalence of ACL injuries in the NFL on natural versus non-natural surfaces to determine if there is a significant increase on non-natural surfaces.

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Needle arthroscopic procedures of the knee offer potential advantages over standard arthroscopic procedures. The small size of the instruments allows for surgery without the use of a scalpel or suture, potentially decreased recovery times, and potentially reduced complication rates compared with traditional arthroscopy. In some patients, the procedure can be performed without the use of either general anesthesia or sedation.

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Objective: It has been shown that verbal working and associative memory have different developmental trajectories with working memory, taking a linear course from early childhood to adolescence, whereas associative memory takes a curvilinear course asymptoting at about age 12. This study made a determination of whether these trajectories tracked with 2 magnetic resonance spectroscopy imaging (MRSI) variables: phosphocreatine level (PCr) and gray matter percentage (GM%).

Method: In a cross-sectional study, 94 children ranging in age from 6-14 years were administered tests of verbal working and associative memory and underwent an MRSI procedure evaluating 6 major brain regions.

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Developmental differences between working and long-term associative memory were evaluated through a cross-sectional age difference study based on data from a memory battery's standardization sample. The scores of 856 children and adolescents ranging from 5 to 17 years of age were compared on memory subtests that assess verbal working and long-term memory. Data were examined using curve fitting and ANOVA procedures that evaluated age group and years of age differences.

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Synaptic development and elimination are normal neurodevelopmental processes, which if altered could contribute to various neuropsychiatric disorders. 31P-1H magnetic resonance spectroscopic imaging (MRSI) and structural magnetic resonance imaging (MRI) exams were conducted on 105 healthy children ages 6-18 years old to identify neuromolecular indices of synaptic development and elimination. Over the age range studied, age-related changes in high-energy phosphate (phosphocreatine), membrane phospholipid metabolism (precursors and breakdown products), and percent gray matter volume were found.

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Context: There is mounting evidence of neurodevelopmental alterations implicating the prefrontal cortex (PFC) and basal ganglia in children with attention-deficit/hyperactivity disorder (ADHD). The brain undergoes substantive structural and functional changes with a differential timing between brain regions during development from childhood to adolescence. In vivo phosphorus 31 magnetic resonance spectroscopy ((31)P MRS) is a noninvasive neuroimaging approach that is sensitive in assessing developmental changes of overproducing/pruning of synapses.

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Biophysical studies of protein-anesthetic interactions using nuclear magnetic resonance (NMR) spectroscopy are often conducted by the addition of micro amounts of neat inhaled anesthetic which yields much higher than clinically relevant (0.2-0.5 mM) anesthetic concentrations.

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Abeta peptide is the major component of senile plaques (SP) which accumulates in AD (Alzheimer's disease) brain. Reports from different laboratories indicate that anesthetics interact with Abeta peptide and induce Abeta oligomerization. The molecular mechanism of Abeta peptide interactions with these anesthetics was not determined.

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Schizophrenia is widely considered a neurodevelopmental disorder. The timing of psychosis onset may determine the degree of functional and biological deficits. In this study, the association between age of onset of psychosis and in vivo biochemical levels was assessed in first-episode, antipsychotic-naive (FEAN) schizophrenia subjects.

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Article Synopsis
  • A (31)P MRS study was conducted on the prefrontal cortex, basal ganglia, and superior temporal region in 10 children with ADHD and 15 healthy controls.
  • ADHD patients showed significantly lower levels of phosphomonoesters in the prefrontal cortex and basal ganglia compared to their healthy peers, while no differences were found in the superior temporal region.
  • These findings imply that children with ADHD may experience a reduction in membrane phospholipid precursor levels, indicating potential underdevelopment of neuronal structures and connections.
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Amyloidogenic proteins (Abeta peptide) in Alzheimer's disease (AD) and alpha-synuclein (alpha-Syn) in Parkinson's disease (PD) are typically soluble monomeric precursors, which undergo remarkable conformational changes and culminate in the form of aggregates in diseased condition. Overlap of clinical and neuropathological features of both AD and PD are observed in dementia with Lewy body (DLB) disease, the second most common form of dementia after AD. The identification of a 35-amino acid fragment of alpha-Syn in the amyloid plaques in DLB brain have raised the possibility that Abeta and alpha-Syn interact with each other.

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Alzheimer's disease (AD) is a significant contributor to cognitive decline and is responsible for about half of the cases of dementia in later life. Although exact etiology of AD is not known, however, many risk factors for AD are identified. Anesthesia for elderly patients is considered as a risk factor in AD as they frequently experience deterioration in cognitive function with long exposure to anesthetics during surgery.

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Prospective studies of young relatives at risk for schizophrenia can shed light on the possible premorbid precursors of the disease. Ongoing studies in Pittsburgh suggest that young non-psychotic high risk relatives have neurobehavioral, brain structural, physiological, and neurochemical deficits that may date back to childhood or earlier. We summarize these data, review the relevant literature in this emerging field, and provide some new data suggesting alterations in sleep architecture in young relatives at risk for schizophrenia.

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Deposition of amyloid beta peptide in human brain in the form of senile plaques is a neuropathological hallmark of Alzheimer's disease (AD). Levels of a phospholipid breakdown product, glycerophosphocholine (GPC), also increase in AD brain. The effect of GPC on amyloid beta(1-40) peptide (Abeta) aggregation in PBS buffer was investigated by circular dichroism and fluoresence spectroscopy; interactions of Abeta and GPC with the intact erythrocyte membrane was examined by fluoresence spectroscopy.

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Amyloid beta peptide (Abeta) is a small peptide present in normal cells and aggregated Abeta is the main constituent of the extracellular amyloid plaques found in Alzheimer's disease (AD) brain. Recent studies suggest that soluble Abeta oligomers are neurotoxic rather than amyloid fibrils found in amyloid plaques. This study using multidimensional NMR spectroscopy and circular dichroism (CD) provides the first direct evidence that alterations in membrane structure can trigger the conversion of soluble alpha-helical monomeric Abeta into oligomeric Abeta in a beta-sheet conformation.

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Acetyl-L-carnitine (ALCAR) is an acetyl derivative of carnitine, an endogenous molecule synthesized in vivo and supplemented by diet (mainly via meat and dairy products). Several parallel, double-blind, placebo-controlled studies have demonstrated that ALCAR treatment produces beneficial effects in geriatric depression. Since most antidepressants also have anti-anxiety effects we examined whether ALCAR shows anti-anxiety effects in a rat model of anxiety.

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Amyloid peptide (Abeta) is the major protein constituent of neuritic plaques in Alzheimer's disease (AD). This peptide is an amphipathic molecule that perturbs membranes and binds to raft-like membranes composed of gangliosides. Ganglioside GM1 binds tightly with Abeta and it is speculated that GM1 inhibits Abeta from undergoing alpha-helix to beta-sheet conformational changes.

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The microstructural integrity of the corpus callosum (CC) in first-episode schizophrenia patients was assessed by measuring the signal intensity (SI) in T1-weighted MRI images. Analyses revealed that compared to both healthy controls and non-schizophrenic patients, schizophrenia patients showed reductions in SI in all the callosal subregions, the genu, body, isthmus and splenium in first-episode schizophrenia. These results indicate that schizophrenia is characterized by pathology of this principal interhemispheric commissure; the abnormalities may reflect distributed (rather than localized) interhemispheric disconnectivity that extends beyond the heteromodal association cortices.

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Objective: Neurological abnormalities are frequently seen in patients with first-episode psychotic disorders but are generally considered to be diagnostically nonspecific, neurologically nonlocalizing, and, hence, "soft." This study examined the neuroanatomical correlates and diagnostic specificity of abnormal findings on the neurological examination in first-episode schizophrenia and other psychotic disorders.

Method: Neuroleptic-naive patients with schizophrenia (N=90) and with nonschizophrenia psychoses (N=39) and carefully matched healthy subjects (N=93) were compared on total and factor scores for a reliable subset of Neurological Evaluation Scale items.

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Acetyl-L-carnitine (ALCAR) and myo-inositol are reported to enhance motor activity in animal models; modulate membrane phospholipid metabolism (ALCAR and myo-inositol) and high-energy phosphate metabolism (ALCAR) back to normal; and be effective treatments of major depression in humans. Fish in general and zebra fish in particular present unique animal models for the in vivo study of high-energy phosphate and membrane phospholipid metabolism by noninvasive in vivo 31P NMR. This 31P NMR study of free-swimming zebra fish showed that both ALCAR and myo-inositol decreased levels of phosphodiesters and inorganic orthophosphate and increased levels of PCr in the fish.

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In vivo (31)P magnetic resonance spectroscopy ((31)P MRS) studies have shown abnormal membrane phospholipid metabolism in the prefrontal cortex (PF) in the early course of schizophrenia. It is unclear, however, whether these alterations also represent premorbid risk indicators in schizophrenia. In this paper, we report in vivo (31)P MRS data on children and adolescents at high risk (HR) for schizophrenia.

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The neurotoxicity of amyloid beta (Abeta) is widely believed to play a seminal role in neurodegeneration in Alzheimer's disease. We examined the effect of Chrysamine G (CG) on such neurotoxicity using the specific measurement of surviving neurons. CG was found to reduce the neurodegeneration induced by both the active short fragment of Abeta(25-35) and full-sized Abeta(1-40).

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Background: There is evidence for membrane abnormalities in schizophrenia. It is unclear whether the observed membrane deficits in peripheral cells parallel central membrane phospholipid metabolism. To address this question we examined the relations between red blood cell polyunsaturated fatty acids and brain phospholipid metabolites from different regions of interest in schizophrenia and healthy subjects.

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