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Biomedical subjects

B E Benson

Publications and source records attributed to B E Benson.

At least 19 recordsLinked to original sources
PubMed2001

Effects of mood and subtype on cerebral glucose metabolism in treatment-resistant bipolar disorder.

BACKGROUND: Functional brain imaging studies in unipolar and secondary depression have generally found decreased prefrontal cortical activity, but in bipolar disorders findings have been more variable. METHODS: Forty-three medication-free, treatment-resistant, predominantly rapid-cycling bipolar disorder patients and 43 age- and gender-matched healthy control subjects had cerebral glucose metabolism assessed using positron emission tomography and fluorine-18-deoxyglucose. RESULTS: Depressed bipolar disorder patients compared to control subjects had decreased global, absolute prefrontal and anterior paralimbic cortical, and increased normalized subcortical (ventral striatum, thalamus, right amygdala) metabolism. Degree of depression correlated negatively with absolute prefrontal and paralimbic cortical, and positively with normalized anterior paralimbic subcortical metabolism. Increased normalized cerebello-posterior cortical metabolism was seen in all patient subgroups compared to control subjects, independent of mood state, disorder subtype, or cycle frequency. CONCLUSIONS: In bipolar depression, we observed a pattern of prefrontal hypometabolism, consistent with observations in primary unipolar and secondary depression, suggesting this is part of a common neural substrate for depression independent of etiology. In contrast, the cerebello-posterior cortical normalized hypermetabolism seen in all bipolar subgroups (including euthymic) suggests a possible congenital or acquired trait abnormality. The degree to which these findings in treatment-resistant, predominantly rapid-cycling patients pertain to community samples remains to be established.

Acoustic Stimulation↗
PubMed2001

Do poison center triage guidelines affect healthcare facility referrals?

BACKGROUND: The purpose of this study was to determine the extent to which poison center triage guidelines influence healthcare facility referral rates for acute, unintentional acetaminophen-only poisoning and acute, unintentional adult formulation iron poisoning. METHODS: Managers of US poison centers were interviewed by telephone to determine their center's triage threshold value (mg/kg) for acute iron and acute acetaminophen poisoning in 1997. Triage threshold values and healthcare facility referral rates were fit to a univariate logistic regression model for acetaminophen and iron using maximum likelihood estimation. RESULTS: Triage threshold values ranged from 120-201 mg/kg (acetaminophen) and 16-61 mg/kg (iron). Referral rates ranged from 3.1% to 24% (acetaminophen) and 3.7% to 46.7% (iron). There was a statistically significant inverse relationship between the triage value and the referral rate for acetaminophen (p < 0.001) and iron (p = 0.0013). The model explained 31.7% of the referral variation for acetaminophen but only 4.1% of the variation for iron. CONCLUSION: There is great variability in poison center triage values and referral rates for iron and acetaminophen poisoning. Guidelines can account for a meaningful proportion of referral variation. Their influence appears to be substance dependent. These data suggest that efforts to determine and utilize the highest, safe, triage threshold value could substantially decrease healthcare costs for poisonings as long as patient medical outcomes are not compromised.

Acetaminophen↗
PubMed2000

Regional cerebral metabolism associated with anxiety symptoms in affective disorder patients.

BACKGROUND: We studied the relationship between regional cerebral metabolism and the severity of anxiety in mood disorder patients, controlling for depression severity. METHODS: Fifty-two medication-free patients with unipolar or bipolar illness underwent positron emission tomography with [(18)F]-fluorodeoxyglucose. Hamilton Depression Rating Scale and Spielberger Anxiety-State Scale scores were obtained for the week of the scan. Analyses were performed on globally normalized images and were corrected for multiple comparisons. RESULTS: After covarying for depression scores, age, and gender, Spielberger Anxiety-State Scale scores correlated directly with regional cerebral metabolism in the right parahippocampal and left anterior cingulate regions, and inversely with metabolism in the cerebellum, left fusiform, left superior temporal, left angular gyrus, and left insula. In contrast, covarying for anxiety scores, age, and gender, Hamilton Depression Rating Scale scores correlated directly with regional cerebral metabolism in the bilateral medial frontal, right anterior cingulate, and right dorsolateral prefrontal cortices. CONCLUSIONS: Comorbid anxiety symptoms are associated with specific cerebral metabolic correlates that partially overlap with those in the primary anxiety disorders and differ from those associated with depression severity.

Adult↗
PubMed2000

Toxicities and outcomes associated with nefazodone poisoning: an analysis of 1,338 exposures.

Toxicities and medical outcomes associated with nefazodone poisoning were characterized using national poisoning data from the American Association of Poison Control Centers and through prospective collection of additional data elements. Nefazodone exposures involving concomitant agents were excluded. There were 1,338 human exposures included in the final data analysis. Seventy-five percent of exposures were acute and 20% involved children < 13 years. Twenty-five percent of patients remained asymptomatic. There were no deaths. No dose response relationship was evident in the 45 cases where estimated doses were available. The most common manifestations were drowsiness (17.3% of all patients), nausea (9.7%), and dizziness (9.5%). The most common serious clinical effect was hypotension (1.6%). The median onset time for symptoms was 1.75 hours. Manifestations resolved within 8 to 24 hours. Most patients were treated with only gastrointestinal decontamination. No patients required intubation, mechanical ventilation, or vasopressors. Nefazodone appears to be of low toxicity during poisonings.

Adolescent↗
PubMed2000

A survey of the expectations of New Mexico emergency physicians regarding the services of the New Mexico Poison and Drug Information Center.

OBJECTIVE: Physicians have been surveyed concerning their satisfaction with poison center services but have never been questioned regarding their expectations. This study was conducted to clarify the expectations of emergency physicians in New Mexico regarding the service of their regional poison center, the New Mexico Poison and Drug Information Center. DESIGN: Five New Mexico emergency department physicians were interviewed about their expectations when calling the New Mexico Poison and Drug Information Center. Their responses were combined with unique, additional expectations identified by the New Mexico Poison and Drug Information Center staff in order to develop a 62-item physician expectation mail survey instrument. Respondents were asked to rank the importance of each service expectation on a 5-point Likert scale (1 = not important, 5 = extremely important). RESULTS: A usable return rate of 60% was achieved (104 surveys). Fifty-eight (94%) expectations had a mean importance rating of > or = 3 (important). Ninety-four percent of the expectations included on the survey were being provided by the New Mexico Poison and Drug Information Center. CONCLUSION: Currently, there is a good fit between New Mexico emergency physician expectations and New Mexico Poison and Drug Information Center services provided. The instrument identified several areas where service was expected but not provided (Internet access to poison center, provision of industrial/occupational toxicology services, provision of tele-medicine capability) and where service was provided but not expected (drug dosing information). Surveying can be a valuable tool for clarifying expectations for poison center services.

Attitude of Health Personnel↗
PubMed2000

Butoxyethanol ingestion with prolonged hyperchloremic metabolic acidosis treated with ethanol therapy.

BACKGROUND: Severe toxic ingestions of butoxyethanol (CAS No. 111-76-2) are rare despite the prevalence of this glycol ether in products such as glass and surface cleaners. Manifestations of acute butoxyethanol toxicity include metabolic acidosis, hemolysis, hepatorenal dysfunction, and coma, but vary widely in reported cases. Furthermore, the optimal therapeutic approach is not yet established. Much of the toxicity of butoxyethanol has been ascribed to its aldehyde and acid metabolites which are similar to those produced by oxidative metabolism of methanol and ethylene glycol. Although the roles of alcohol dehydrogenase inhibition with ethanol or fomepizole and hemodialysis are clear in the case of toxic ingestions of methanol and ethylene glycol, they remain poorly defined for butoxyethanol poisoning. CASE REPORT: We report the case of a 51-year-old female who ingested up to 8 ounces of Sanford Expo White Board Cleaner (butoxyethanol and isopropanol). She developed prolonged hyperchloremic metabolic acidosis and mental status depression and was treated with ethanol therapy but not hemodialysis. This patient recovered without apparent sequelae. The kinetics of butoxyethanol metabolism in this case are described and the potential therapeutic options are discussed.

Acidosis↗
PubMed1999

Frequency dependence of antidepressant response to left prefrontal repetitive transcranial magnetic stimulation (rTMS) as a function of baseline cerebral glucose metabolism.

BACKGROUND: Recent studies suggest that both high frequency (10-20 Hz) and low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) have an antidepressant effect in some individuals. Electrophysiologic data indicate that high frequency rTMS enhances neuronal firing efficacy and that low frequency rTMS has the opposite effect. METHODS: We investigated the antidepressant effects of 10 daily left prefrontal 1 Hz versus 20 Hz rTMS with the hypothesis that within a given subject, antidepressant response would differ by frequency and vary as a function of baseline cerebral glucose metabolism. After baseline PET scans utilizing [18F]-Fluorodeoxyglucose, thirteen subjects participated in a randomized crossover trial of 2 weeks of 20 Hz paired with 2 weeks 1 Hz or placebo rTMS. RESULTS: We found a negative correlation between degree of antidepressant response after 1 Hz compared to 20 Hz rTMS (r = -0.797, p < .004). Additionally, better response to 20 Hz was associated with the degree of baseline hypometabolism, whereas response to 1 Hz rTMS tended to be associated with baseline hypermetabolism. CONCLUSIONS: These preliminary results suggest that antidepressant response to rTMS might vary as a function of stimulation frequency and may depend on pretreatment cerebral metabolism. Further studies combining rTMS and functional neuroimaging are needed.

Adult↗
PubMed1999

Baseline cerebral hypermetabolism associated with carbamazepine response, and hypometabolism with nimodipine response in mood disorders.

BACKGROUND: Positron emission tomography (PET) studies have reported baseline (medication free) differences between mood disorder patients and healthy control subjects, but relatively little is known about relationships between baseline PET scans and treatment responses. Carbamazepine (CBZ) and to a more limited extent nimodipine (NIMO) seem useful in mood disorders. We explored whether baseline regional cerebral glucose metabolism (rCMRglu) could discriminate CBZ and NIMO responders from nonresponders and healthy control subjects. METHODS: In refractory mood disorder patients, we examined relationships between responses to these drugs, assessed by Clinical Global Impression-Improvement scores, and baseline rCMRglu, determined with fluorine-18 deoxy-glucose and PET. RESULTS: CBZ responders had baseline left insular hyper-metabolism compared to healthy control subjects and nonresponders, whereas nonresponders had widespread (including left insular) hypometabolism. Degree of CBZ response correlated with baseline paralimbic (including insula) and prefrontal hypermetabolism. In responders but not nonresponders, CBZ decreased widespread metabolism, with the degree of decrease in left insula correlating with response. In contrast, NIMO responders but not nonresponders had baseline widespread (including left insular) hypometabolism. Left prefrontal and left insular baseline hypometabolism, but not metabolic changes with treatment correlated with degree of NIMO response. CONCLUSIONS: These data suggest that baseline anterior paralimbic and prefrontal hypermetabolism may be associated with CBZ response, and hypometabolism with NIMO response. Based on these preliminary data, further exploration of relationships between baseline PET scans and treatment responses is indicated.

Adult↗
PubMed1999

Regional brain activity during transient self-induced anxiety and anger in healthy adults.

BACKGROUND: Several studies have demonstrated that transient self-induced sadness activates anterior paralimbic structures. To further examine the specificity of these findings and the neural substrates involved in anger and anxiety, we studied the neural correlates of the induction of anxiety and anger in healthy adults. METHODS: We used H2(15)O and positron emission tomography (PET) to measure regional cerebral blood flow (rCBF) in 16 healthy adults during the induction of transient anxiety, anger, and neutral emotions. Subjects achieved differential emotions by recalling prior life events while viewing affect-appropriate faces. RESULTS: Both the anxiety and anger conditions were associated with increased normalized rCBF in left inferior frontal and left temporal pole regions and decreased rCBF in right posterior temporal/parietal and right superior frontal cortex, compared to the neutral induction. Additionally, compared to neutral induction, anxiety was associated with increased rCBF in the left anterior cingulate and cuneus and decreased rCBF in right medial frontal cortex, while the anger induction was uniquely associated with increased rCBF in right temporal pole and thalamus. CONCLUSIONS: Self-generated transient states of anxiety and anger are associated with both overlapping and distinct regional brain activity patterns and provide a template for further dissection of specific components of normal and pathologic emotions.

Adult↗
PubMed1997

Rapid onset: a valid panic disorder criterion?

This study examined the value of the DSM-IV time criterion for panic disorder (PD) requiring an abrupt onset to panic attacks (PAs) with a time to peak intensity (TTPI) of less than 10 min, and evaluated features distinguishing rapid onset (TTPI < 10) from prolonged onset (TTPI > 10) panickers. Eight hundred and sixty-four respondents to the National Institute of Mental Health Panic Disorder Questionnaire (NIMH PQ) who met the first three PD criteria were compared based on the time criterion. The prolonged onset panickers (18.2%) did not differ significantly from rapid onset panickers (81.8%) on any of 100 items assessing clinical symptoms, course of illness, and comorbidity of PD. These results suggest that many patients with otherwise classic features of PD have a prolonged TTPI of PAs, and that patients with prolonged-onset PAs are similar to patients with rapid-onset PAs on most measures. The reliability, validity, and clinical relevance of the current DSM-IV TTPI criterion should be evaluated in future studies.

Adult↗
PubMed1997

Prospective multicenter evaluation of tramadol exposure.

BACKGROUND: Tramadol is a novel analgesic possessing both opiate and noradrenergic effects. Its low potential for abuse suggests increasing use, but there are limited data on the toxicity in overdose. METHODS: Multicenter prospective case series. All exposures from October 1995 through August 1996 reported to seven Poison Centers were evaluated. RESULTS: There were 126 cases of which 87 were tramadol alone. Of the tramadol alone cases, 51 were female (59%). Age ranged from 1 to 86 y with a mean and median of 26.8 y (SD 17.2) and 25 y, respectively. There were 15 cases of children less than 6 years old. Symptoms reported with overdose were: lethargy 26 (30%), nausea 12 (14%), tachycardia 11 (13%), agitation 9 (10%), seizures 7 (8%), 4 each (5%) of coma and hypertension, and respiratory depression 2 (2%). All seizures were brief. Naloxone reversed sedation and apnea in 4 of 8 patients. One patient experienced a seizure immediately after administration of naloxone. Other treatments were: diazepam (3 patients), and phenytoin, lorazepam and nifedipine (1 patient each). Tramadol 500 mg was the lowest dose associated with seizure, tachycardia, hypertension or agitation while 800 mg was the lowest dose associated with coma and respiratory depression. Urine drug screens performed on 19 patients were negative for opiates. All symptomatic cases exhibited effects within 4 h of ingestion. Mean hospital stay was 15.2 h (range 2-96 h, SD 15.8). Nineteen patients were admitted to an intensive care unit with a mean stay of 25 h (SD 20). DISCUSSION: Much of the toxicity in tramadol overdose appears to be attributable to the monoamine uptake inhibition rather than its opioid effects. Agitation, tachycardia, confusion and hypertension suggest a possible mild serotonin syndrome. No arrhythmias beyond tachycardia were seen. CONCLUSION: This study suggests significant neurologic toxicity from tramadol overdose. Serious cardiovascular toxicity was not seen.

Adolescent↗
PubMed1991

Pharmacists' poison prevention advice to the elderly.

Up to 36% of childhood ingestions take place in grandparents' homes. We surveyed the 1544 registered pharmacists in the state of Nebraska by a mailed anonymous questionnaire concerning their poison prevention practices with the elderly. Of the 26% respondents, 75% always or usually gave older adults a choice of child-resistant containers but estimated that 65% chose non-child-resistant containers. Fifty-two percent reported that they asked older adults about children who could possibly ingest medications, and 59% reported that they had poison prevention material available. However, over 50% of pharmacists reported that they neither actively counseled nor handed out poison prevention material to the elderly, and only 9% reported that they specifically advise older adults about poison prevention. If all pharmacists targeted poison control education to the elderly, childhood poisoning by drugs could be reduced by one-third.

Adult↗
PubMed1987

Chlorine inhalation toxicity from vapors generated by swimming pool chlorinator tablets.

We have presented two cases of serious respiratory injury after brief exposure to vapors from solid chlorine compounds. We could find no previous reports of such accidents and, therefore, have related these cases to alert the medical community. We would recommend that physicians caring for children include warnings about these preparations in their routine counseling of parents.

Child↗
PubMed1986

A severe organophosphate poisoning requiring the use of an atropine drip.

A 68-year-old male attempted suicide by drinking three ounces of concentrated Cygon 2-E (23.4% dimethoate). He was immediately brought to the hospital, responded to standard treatment (ipecac, activated charcoal, 2-PAM, atropine), and was transferred from the ICU to general care 24 hours after the exposure. Within eight hours of the transfer, he relapsed and was moved to the CCU, where he required five milligrams of atropine every ten minutes for 24 hours, before being started on an atropine drip. The patient was maintained on the atropine drip (0.5-2.4 mg/kg/hr) for five weeks. He required a total atropine dose of 30 grams, the largest amount ever reported to have been administered to a human. Although S-ChE activities gradually increased they were not found to be helpful in determining when the drip could be safely stopped. Control of hypersecretions served as the best monitoring parameter for titration of the drip rate. The patient recovered completely with the exception of a detectable sensorineural hearing deficit, a slight, nonspecific personality change, and minimal spastic rigidity thought to be secondary to several anoxic episodes.

Aged↗