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Biomedical subjects

P L Peterson

Publications and source records attributed to P L Peterson.

At least 19 recordsLinked to original sources
PubMed2003

Quantitative magnetic resonance imaging in neuropsychiatric systemic lupus erythematosus.

Neuropsychiatric symptoms are common in systemic lupus erythematosus (SLE) but are poorly understood. Although there is a wide spectrum of clinical manifestations, brain histology often simply shows a bland vasculopathy. Magnetic resonance techniques such as magnetic resonance spectroscopy, magnetization transfer imaging and diffusion weighted imaging have been used to try to improve our understanding of the pathophysiological mechanisms involved in neuropsychiatric lupus (NPSLE). This article reviews the current literature on the use of these techniques and their possible future role as diagnostic tools in NPSLE.

Brain↗
PubMed2001

Appearance of shortened Bcl-2 and Bax proteins and lack of evidence for apoptosis in rat forebrain after severe experimental traumatic brain injury.

To investigate whether apoptosis plays a role in traumatic brain injury (TBI), we examined the expression of Bcl-2 and Bax proteins and the release of mitochondrial cytochrome c in rat brains using Western blot analysis. Bcl-2 at the predicted 26 kDa was not detected in controls and TBI groups. However, at 1 h post-TBI, a shortened Bcl-2 protein with a molecular size of approximately 14.5 kDa was detected in the injured hemisphere (R). At 4 and 12 h post TBI, an additional bcl-2 band ( approximately 10 kDa) was detected in R. Both bands disappeared at 14 days post-injury. The predicted 21-kDa band of Bax was detected in both controls and TBI animals. In addition, two shortened Bax proteins ( approximately 18 kDa) were detected after TBI. The time course of appearance was similar to that of Bcl-2 described above. In the present study, neither cytochrome c release from mitochondria nor DNA fragmentation was detected in the forebrains of sham and TBI groups. Treatment of animals with an antioxidant N-acetylcysteine administered ip greatly diminished the levels of shortened Bcl-2 and Bax proteins. These findings suggest that the induction of shortened Bcl-2 and Bax proteins in rat brains may be associated with reactive oxygen species generated after TBI.

Acetylcysteine↗
PubMed2000

Impaired cerebral mitochondrial function after traumatic brain injury in humans.

OBJECT: Oxygen supply to the brain is often insufficient after traumatic brain injury (TBI), and this results in decreased energy production (adenosine triphosphate [ATP]) with consequent neuronal cell death. It is obviously important to restore oxygen delivery after TBI; however, increasing oxygen delivery alone may not improve ATP production if the patient's mitochondria (the source of ATP) are impaired. Traumatic brain injury has been shown to impair mitochondrial function in animals; however, no human studies have been previously reported. METHODS: Using tissue fractionation procedures, living mitochondria derived from therapeutically removed brain tissue were analyzed in 16 patients with head injury (Glasgow Coma Scale Scores 3-14) and two patients without head injury. Results revealed that in head-injured patients mitochondrial function was impaired, with subsequent decreased ATP production. CONCLUSIONS: Decreased oxygen metabolism due to mitochondrial dysfunction must be taken into account when clinically defining ischemia and interpreting oxygen measurements such as jugular venous oxygen saturation, arteriovenous difference in oxygen content, direct tissue oxygen tension, and cerebral blood oxygen content determined using near-infrared spectroscopy. Restoring mitochondrial function might be as important as maintaining oxygen delivery.

Adolescent↗
PubMed2000

Improvement in mitochondrial dysfunction as a new surrogate efficiency measure for preclinical trials: dose-response and time-window profiles for administration of the calcium channel blocker Ziconotide in experimental brain injury.

OBJECT: Determining the efficacy of a drug used in experimental traumatic brain injury (TBI) requires the use of one or more outcome measures such as decreased mortality or fewer neurological and neuropsychological deficits. Unfortunately, outcomes in these test batteries have a fairly large variability, requiring relatively large sample sizes, and administration of the tests themselves is also very time consuming. The authors previously demonstrated that experimental TBI and human TBI induce mitochondrial dysfunction. Because mitochondrial dysfunction is easy to assess compared with neurobehavioral endpoints, it might prove useful as an outcome measure to establish therapeutic time windows and dose-response curves in preclinical drug testing. This idea was tested in a model of TBI in rats. METHODS: Animals treated with the selective N-type voltage-sensitive calcium channel blocker Ziconotide (also known as SNX-111 and CI-1009) after cortical impact displayed significant improvement in brain mitochondrial function. When a single intravenous bolus injection of 4 mg/kg Ziconotide was given at different time intervals, ranging from 15 minutes before injury to 10 hours after injury, mitochondrial function was improved at all time points, but more so between 2 and 6 hours postinjury. The authors evaluated the effects on mitochondrial function of Ziconotide at different doses by administering 0.5 to 6 mg/kg as a single bolus injection 4 hours after injury, and found 4 mg/kg to be the optimum dose. CONCLUSIONS: The authors established these time-window profiles and dose-response curves on the basis of mitochondrial outcome measures in a total of 42 rats because there were such low standard deviations in these tests. Establishing similar time-window profiles and dose-response curves by using neurobehavioral endpoints would have required using 114 rats in much more elaborate experiments.

Animals↗
PubMed2000

Wisconsin, July 1999 heat wave: an epidemiologic assessment.

OBJECTIVE: To assess the characteristics of heat-related deaths in Wisconsin during the summer of 1999. METHODS: Review of death certificates indicating heat as an underlying or contributing cause of death. RESULTS: Heat-related illness led to 21 deaths during the summer of 1999 in Wisconsin. The rate of death was highest in the elderly, particularly those aged 65-84 years (2.2/100,000). Heat was the underlying cause for 12 of the 21 deaths. Cardiovascular conditions were the underlying cause in 8 of the deaths, and a contributing cause for another 7. CONCLUSIONS: The elderly, persons taking psychotropic medications, and persons with chronic diseases, particularly cardiovascular conditions, are at increased risk of death from heat during heat waves. Prevention messages and weather advisories during heat emergencies must target these groups. Care givers and medical personnel must be on heightened awareness for the signs and symptoms of heat exhaustion and heat stroke during these periods.

Age Factors↗
PubMed1999

Effect of N-acetylcysteine on mitochondrial function following traumatic brain injury in rats.

Efficacy of N-acetylcysteine (NAC) in traumatic brain injury (TBI)-induced mitochondrial dysfunction was evaluated following controlled cortical impact injury in rats. Respiratory function and calcium transport of rat forebrain mitochondria from injured and uninjured hemispheres were examined. NAC significantly restored mitochondrial electron transfer, energy coupling capacity, calcium uptake activity and reduced calcium content absorbed to brain mitochondrial membranes when examined 12 h post-TBI if NAC was administered i.p. 5 min before injury or 30 min or 1 h postinjury. Glutathione (reduced form, GSH) levels in brain tissues were decreased at all time points examined over a 14-day observation period, while mitochondrial GSH levels significantly decreased only at 3 days and 14 days following TBI. NAC treatment given within 1 h greatly restored brain GSH levels from 1 h to 14 days and mitochondrial GSH levels from 12 h to 14 days post-TBI. NAC did not show protective effects when given 2 h postinjury. Our data indicate that NAC administered postinjury at an early stage can effectively restore TBI-induced mitochondrial dysfunction and the protective effect of NAC may be related to its restoration of GSH levels in the brain.

Acetylcysteine↗
PubMed1998

Mitochondrial dysfunction after experimental traumatic brain injury: combined efficacy of SNX-111 and U-101033E.

We recently demonstrated that posttraumatic administration of the N-type calcium channel blocker SNX-111 (S) and a novel blood-brain barrier penetrating antioxidant U-101033E (U), significantly alleviated mitochondrial dysfunction induced by traumatic brain injury (TBI) in rats. The present study was designed to determine whether a combination of S and U, which act on different biochemical mechanisms of secondary brain injury, would be more efficacious than either drug alone. Brain mitochondria from injured and uninjured hemispheres were isolated and examined at 12 h post TBI induced by a severe controlled cortical impact injury. S at 1.0 mg/kg significantly increased both State 3 and 4 rates and produced a slight increase in P/O ratio, and there was virtually no change in RCI. U at 1.0 mg/kg did not show any protection. However, the combined treatment of S at 1.0 mg/kg and U at 1.0 mg/kg eliminated the uncoupling effect of S, and restored not only State 3 rates and P/O ratios but also RCI to near sham values. These results provide further evidence that both reactive oxygen species and perturbation of cellular calcium homeostasis participate in the pathogenesis of TBI-induced mitochondrial dysfunction, and support the idea of using combined therapy with lower drug doses.

Analysis of Variance↗
PubMed1998

The pathophysiology of brain injury: understanding innovative drug therapies.

The advancement of acute care for persons with brain injury is predicated on the further clarification of the mechanical and biochemical processes that are begun at the time of the injury. Attempts to enhance survival and functional outcome have led to cerebral perfusion and intracranial pressure management techniques. In addition, novel neuroprotective pharmacotherapeutic strategies have been borne from an ever growing knowledge of the degradative biochemical injury that occurs subsequent to the initial insult. The link between the acute and rehabilitation phases of care continues to grow closer, thus compelling the rehabilitationist to be aware of the potential effect these processes and treatments have on outcome.

Animals↗
PubMed1997

Mitochondrial dysfunction after experimental and human brain injury and its possible reversal with a selective N-type calcium channel antagonist (SNX-111).

We have recently demonstrated in a rat model that traumatic brain injury induces perturbation of cellular calcium homeostasis with an overload of cytosolic calcium and excessive calcium adsorbed on the mitochondrial membrane, consequently the mitochondrial respiratory chain-linked oxidative phosphorylation was impaired. We report the effect of a selective N-type calcium channel blocker, SNX-111 on mitochondrial dysfunction induced by a controlled cortical impact. Intravenous administration of SNX-111 at varying times post injury was made. The concentration titration profile revealed SNX-111 at 4 mg kg-1 to be optimal, and the time window to be administration at 4 h post-injury, in line with that reported on the effect of SNX-111 in experimental stroke. Under optimal conditions, SNX-111 significantly improved the mitochondrial respiratory chain-linked functions, such as the electron transfer activities with both succinate and NAD-linked substrates, and the accompanied energy coupling capacities measured as respiratory control indices (RCI) and ATP synthesis (P/O ratio), and the energy linked Ca2+ transport. In order to assess the applicability of these data to the clinical setting, we have initiated studies with brain tissue which has to be resected during surgical treatment. Five patients suffered from brain trauma, one from intracranial hypertension due to stroke (noninfarcted tissue was taken), and one from epilepsy. Our data revealed that brain mitochondria derived from the patient with intracranial hypertension and the patient with epilepsy were tightly coupled with good respiratory rates with glutamate and malate as substrates, and high P/O ratios. The rates of respiration and ATP synthesis were severely impaired in the brain mitochondria isolated from traumatized patients. These results indicate that investigation of brain mitochondrial functions can be used as a measure for trauma-induced impairment of brain energy metabolism. The time window for the effect of SNX-111 in mitochondrial function and the (preliminary) similarity between mitochondrial dysfunction in experimental animals and humans make the drug appear to be well suited for clinical trials in severe head injury.

Animals↗
PubMed1997

Mitochondrial dysfunction and calcium perturbation induced by traumatic brain injury.

Traumatic brain injury (TBI) is associated with primary and secondary injury. A thorough understanding of secondary injury will help to develop effective treatments and improve patient outcome. In this study, the GM model of controlled cortical impact injury (CCII) of Lighthall (1988) was used with modification to induce lateral TBI in rats. Forebrain mitochondria isolated from ipsilateral (IH) and contralateral (CH) hemispheres to impact showed a distinct difference. With glutamate + malate as substrates, mitochondria from the IH showed a significant decrease in State 3 respiratory rates, respiratory control indices (RCI), and P/O ratios. This decrease occurred as early as 1 h and persisted for at least 14 days following TBI. The State 3 respiratory rates, RCI, and P/O ratios could be restored to sham values by the addition of EGTA to the assay mixture. A significant amount of Ca2+ was found to be adsorbed to the mitochondria of both the IH and the CH with higher values seen in the IH. The rate of energy-linked Ca2+ transport in the IH was significantly decreased at 6 and 12 h. These data indicate that CCII-induced TBI perturbs cellular Ca2+ homeostasis and results in excessive Ca2+ adsorption to the mitochondrial membrane, which subsequently inhibits the respiratory chain-linked electron transfer and energy transduction.

Animals↗
PubMed1997

Amelioration of mitochondrial function by a novel antioxidant U-101033E following traumatic brain injury in rats.

In the present study, a severe traumatic brain injury (TBI) was produced over the right parietal cortex of rats using the controlled cortical impact injury (CCII) model. TBI perturbed calcium homeostasis and impaired electron transfer and energy coupling activities of forebrain mitochondria isolated from injured hemispheres with a maximal injury at 12-72 h. Efficacy of the blood-brain barrier penetrating antioxidant U-101033E on TBI-induced mitochondrial impairment was evaluated. In the dose-response experiment, two i.v. boluses (vehicle or 1-10 mg/kg of U-101033E) were administered at 5 min and 2h post-TBI. Forebrain mitochondria from each hemisphere were examined at 12 h post-injury. With respect to forebrain mitochondrial dysfunction, the drug showed a bell-shaped dose-response curve with an optimal dose of 3 mg/kg (n = 5, p < 0.05 vs. vehicle). In the time-course experiment, two i.v. boluses of 3 mg U-101033E/kg (the optimal dose) were given at 5 min and 2 h post-injury and forebrain mitochondria were examined at 6 h-14 days post-injury. U-101033E significantly restored electron transfer, energy coupling capacity, and Ca2+ transport capacity during 6 h to 14 days post-injury. Our data indicate that the antioxidant U-101033E administered post-injury at proper dosage can effectively restore TBI-induced mitochondrial dysfunction and support the contention that oxidative stress plays an important role in the pathogenesis of TBI.

Animals↗
PubMed1995

The treatment of mitochondrial myopathies and encephalomyopathies.

This paper briefly summarizes the results of a long-term, open pharmacotherapy trial in 16 patients with well-characterized mitochondrial disease. Outcome measures included repeated clinical evaluation, 31P-NMR spectroscopy and near-infrared spectroscopy. Treated patients appeared to survive longer with less functional disability and medical complications than typically seen in clinical practice.

Adolescent↗
PubMed1995

Evaluation of a self-help program to reduce alcohol consumption among pregnant women.

This study tested a cognitive-behavioral intervention for reducing alcohol consumption among economically disadvantaged pregnant women. The intervention included a 10-minute educational session and a nine-step self-help manual. Women attending public health maternity clinics completed a screening questionnaire, a pretest questionnaire, were randomly assigned to receive the self-help intervention or usual clinic care, and completed a posttest questionnaire. A higher alcohol quit rate was observed among the intervention participants (88%) than controls (69%). The effect was strongest for "light" drinkers, African-Americans, and non-Protestants. This approach may be useful in clinics where staff time is limited.

Alcohol Drinking↗
PubMed1994

Outpatient treatment for cocaine abuse: a controlled comparison of relapse prevention and twelve-step approaches.

This study sought to assess the efficacy of treatment for cocaine abuse and to compare the relative effectiveness of a cognitive-behavioral relapse prevention treatment with that of a Twelve-Step recovery support group in an outpatient group treatment setting. One hundred ten subjects seeking treatment were alternately assigned to relapse prevention or Twelve-Step treatment. Self-report data were collected at baseline, posttreatment, and 6-month follow-up. There were no differential effects of treatment type on cocaine or marijuana use over time. However, subjects in both treatment conditions reduced cocaine and marijuana use at posttreatment. Subjects in both groups reduced their alcohol use from pretreatment to posttreatment. Subjects receiving Twelve-Step treatment showed greater increases from posttreatment to 6-month follow-up in alcohol use than did relapse prevention participants. Treatment attendance was negatively related to cocaine use at posttreatment and cocaine and marijuana use at 6-month follow-up. Difficulties in conducting cocaine treatment outcome research are discussed as are treatment and research implications of the findings.

Adult↗
PubMed1994

Blunt head trauma: comparison of various weapons with intracranial injury and neurologic outcome.

The weapons used in blunt head trauma cases were identified to determine if a particular weapon was associated with a specific type of intracranial injury or a poorer neurologic outcome. A consecutive sample of 178 patients was examined. Forty-seven percent of patients beaten with baseball bats and 63% of patients beaten with fists had positive computed tomographic (CT) findings. Twenty five percent of patients beaten with bats and 48% of those beaten with fists had poor neurologic outcomes (p < 0.056). Of those with positive CT findings, 30% of patients beaten with bats and 59% of patients beaten with fists had a poor outcome (p = 0.511). No weapon was associated with a particular intracranial injury. Of assault victims who survive an attack and require admission to the hospital, those beaten with bats are less likely to have significant neurologic dysfunction upon hospital discharge than those beaten with fists.

Adolescent↗
PubMed1992

Gastric mucosal damage due to aspirin and copper aspirinate assessed by gastric mucosal potential difference changes.

When the gastric mucosa is damaged by antiinflammatory agents, such as aspirin, gastric mucosal potential difference (GPD) decreases and may or may not return to predamage values after the agent is removed. The magnitude and time course of the gastric potential difference changes have been suggested as a measure of mucosal damage. Male Sprague-Dawley rats were fasted, anesthetized, and surgically prepared for measurement of GPD by placement of electrodes in the gastric lumen and spleen. Test mixtures of aspirin, copper aspirinate, copper sulfate, or mixtures of aspirin and copper sulfate were administered by gavage, and subsequent changes in GPD were recorded. The area between the extrapolated control (baseline) GPD and the damage GPD was determined. The product of this area and the maximum change in GPD, the Reizindex (RI), was calculated. Values for all copper (II)-containing systems, including those with no aspirin, were significantly greater than aspirin alone. It was concluded that factors other than mucosal damage may contribute to a reduction in GPD and, therefore, an increase in Reizindex.

Animals↗
PubMed1992

Preventing fetal alcohol exposure: a cognitive behavioral approach.

Fetal alcohol exposure is a serious social and public health problem. However, most prevention programs in this area are solely informational. Important gaps in both understanding processes which underlie alcohol consumption during pregnancy and in the design of interventions to prevent fetal alcohol exposure are discussed. We argue that an important group missed by current interventions are women for whom abstinence is difficult, but who are not physically addicted. Cognitive behavioral interventions are proposed as appropriate for this target group. Recommendations for future directions in the area of fetal alcohol exposure are discussed.

Adult↗