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Dive into the research topics where Richard C. Risser is active.

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Featured researches published by Richard C. Risser.


Journal of Child and Adolescent Psychopharmacology | 2001

A prospective open-label treatment trial of olanzapine monotherapy in children and adolescents with bipolar disorder

Jean A. Frazier; Joseph Biederman; Mauricio Tohen; Peter D. Feldman; T. Jacobs; V. Toma; Michael Rater; Reem Tarazi; Grace S. Kim; Stacey B. Garfield; Mari Sohma; Joseph Gonzalez-Heydrich; Richard C. Risser; Zachary M. Nowlin

OBJECTIVE The goal of this study was to assess the effectiveness and tolerability of olanzapine in the treatment of acute mania in children and adolescents. METHODS This was an 8-week, open-label, prospective study of olanzapine monotherapy (dose range 2.5-20 mg/day) involving 23 bipolar youths (manic, mixed, or hypomanic; 5-14 years old). Weekly assessments were made using the Young Mania Rating Scale (YMRS), Clinical Global Impressions Severity Scale (CGI-S), Brief Psychiatric Rating Scale, and Childrens Depression Rating Scale. Adverse events were assessed through self-reports, vital sign and weight monitoring, laboratory analytes, and extrapyramidal symptom rating scales (Barnes Akathisia Scale, Simpson-Angus Scale, and Abnormal Involuntary Movement Scale). RESULTS Twenty-two of the 23 youths (96%) completed the study. Olanzapine treatment was associated with significant improvement in mean YMRS score (-19.0 +/- 9.2, p < 0.001). Using predefined criteria for improvement of > or = 30% decline in the YMRS and a CGI-S Mania score of < or = 3 at endpoint, the overall response rate was 61%. Overall, olanzapine was well tolerated, and extrapyramidal symptom measures were not significantly different from baseline. Body weight increased significantly over the study (5.0 +/- 2.3 kg, p < 0.001). CONCLUSIONS Open-label olanzapine treatment was efficacious and well tolerated in the treatment of acute mania in youths with bipolar disorder. Future placebo-controlled, double-blind studies are warranted.


Biological Psychiatry | 1997

Cortisol secretion and Alzheimer's disease progression

Myron F. Weiner; Stephen Vobach; Kirsten Olsson; Doris Svetlik; Richard C. Risser

BACKGROUND Mild hypercortisolemia is a frequent concomitant of Alzheimers disease (AD). In an effort to ascertain the relationship between serum cortisol concentration (CORT) and disease progression, aging, and survival, we followed 9 persons with AD, ages from 56 to 84 years, from an original cohort of 19 enrollees with serial cognitive testing and CORT determinations. METHODS The cognitive instrument was a modification of the Alzheimers Disease Assessment Scale-Cognitive (mADAS-COG). Serum cortisol determinations were performed at noon, and an Afternoon Cortisol Test (ACT) was used to obtain an estimate of average CORT. RESULTS Baseline 12:00 hours CORT but not ACT correlated significantly with the change in mADAS-COG (r = .90, p < .01). ACT levels increased as the mADAS-COG increased over time (p = .037), by 0.156 +/- 0.06 microgram/dL for each one-point increase (indicating greater impairment) in cognitive test score. ACT levels did not increase significantly simply with aging. For the entire cohort of 19 subjects, neither baseline ACT nor 12:00 hours CORT was significantly related to survival. CONCLUSIONS Hypercortisolemia in AD appears related to the clinical progression of the disease, but not to aging or length of survival.


Transplantation | 1992

Intraoperative albumin administration affects the outcome of cadaver renal transplantation

Ingemar Dawidson; Zsolt F. Sandor; Coorpender L; Biff F. Palmer; Paul C. Peters; Christopher Y. Lu; Arthur I. Sagalowsky; Richard C. Risser; Chris Willms

The prognostic significance of early malfunction or delayed function after cadaveric renal transplantation is controversial. This study examines the influence of intraoperative management in 438 cadaveric renal transplant recipients on seven posttransplant outcome measures: (1) time of onset of urine output, (2) urine volume, (3) renal function, (4) incidence of delayed function, (5) never-functioning kidney, (6) graft survival, and (7) patient survival. Delayed function, defined as the need for hemodialysis during the first posttransplant week, decreased from 46% in 1982 to 15% in 1990 and was associated with a 25% lower 1-year graft survival rate and a mortality rate of 10% at 3 months, compared with 3% when immediate function was present. The most important factors influencing the outcome were cold ischemia time (P = 0.007), intraoperative administration of albumin (P = 0.0027), duration of surgery (P = 0.020), and recipient age (P = 0.041). A high albumin dose (1.2-1.6 g/kg bodyweight) induced urine output within 30 min in 75% of patients and induced larger urine volumes (7.3 L/24 hr), as compared with the effects of a low dose (0-0.4 g/kg), which induced urine output within 30 min in 39% and only 3.7 L/24 hr. Serum creatinine at 1 week was 3.4 and 5.8 mg/dl for the high and low albumin doses, respectively (P less than 0.0001). Similarly, mean glomerular filtration rates at 1 and 7 days were 33 and 21 ml/min, compared with 47 and 28 ml/min, for the high and low albumin doses, respectively (P less than 0.01). The incidence of delayed function and of never-functioning kidneys declined from 34% and 9% for the low dose to 12% and 1% for the high dose, respectively. Finally, with increasing albumin dose, the graft survival rate at 1 year improved from 59 to 78% (P less than 0.002), and the patient mortality rate at 3 months dropped from 6% to 2%. For albumin dose intervals between the high (1.2-1.6 g/kg) and low (0-0.4 g/kg), the effect on all seven outcome measures was intermediate, generally describing a linear relationship. Weighted least-squares analysis of the relationship of delayed function with high vs. low doses of albumin, mannitol, furosemide, and volumes of crystalloid solutions showed significance only for the albumin effect. High-dose albumin infusion likely produces intravascular volume expansion and achieves a prompt restoration of blood flow, minimizes hypoxic injury, and helps preserve renal tissue. The possibility of other beneficial effects of albumin unrelated to intravascular volume also exists.(ABSTRACT TRUNCATED AT 400 WORDS)


Pediatric Neurology | 1997

Pregnancy-induced hypertension and reduced intraventricular hemorrhage in preterm infants

Jeffrey M. Perlman; Richard C. Risser; Jerry B Gee

Increasing evidence suggests that the incidence of periventricular intraventricular hemorrhage (PV-IVH) is lower in infants born to mothers with pregnancy-induced hypertension (PIH). The mechanism or mechanisms accounting for this reduction remain unclear but may be related to PIH itself, medications used to treat the mother (e.g., magnesium sulfate), or to obstetrical management. In this retrospective analysis, we determined the incidence of PV-IVH in singleton preterm infants weighing less than 1,500 gm born to mothers with PIH who were also administered magnesium sulfate. Between January 1988 and December 1994, 254 singleton infants born to mothers with PIH and 1,083 born to mothers without PIH were studied. PV-IVH developed in 360 (26.9%) of the 1,337 infants; 977 (74.1%) infants did not exhibit PV-IVH. The incidence of total as well as severe PV-IVH was lower in infants born to mothers with PIH than in those without PIH [i.e., 16% vs 30% (total) and 8.2% vs 14.5% (severe), P < .001] with an odds ratio (OR) estimate of 0.43 [95% confidence interval (CI) 0.30, 0.61]. Infants born to mothers with PIH weighed more, (1,152 +/- 250 gm vs 1,058 +/- 283 gm, P < .001) and were more mature (30.1 +/- 2.9 vs 27.7 +/- 31 weeks, P < .001) than infants born to mothers without PIH. These infants were also less likely to be exposed to labor (57% vs 93%), to be delivered by cesarean section (81% vs 35%), and to require intubation (49% vs 58%), but more likely to exhibit respiratory distress syndrome (RDS) (47% vs 38%, P < .01). By logistic regression analysis, after seven variables (i.e., PIH, gestational age, and birthweight, both modeled as cubic polynomials; labor; intubation; RDS; and race) were included in the analytic model, PIH remained a significant predictor of IVH: P = .006, OR = 0.54 (95% CI 0.349, 0.847). These data indicate a significantly lower incidence of PV-IVH of approximately 50% in infants born to mothers with PIH as compared with the incidence in infants born to mothers without PIH, despite their higher incidence of RDS. The reduction in PV-IVH may be directly related to the PIH; however, the independent role of antenatal magnesium sulfate administration requires further study.


Journal of the American College of Cardiology | 1995

Predictors of systolic and diastolic improvement in patients with dilated cardiomyopathy treated with metoprolol

Eric J. Eichhorn; Christian M. Heesch; Richard C. Risser; Lucille Marcoux; Barbara A. Hatfield

OBJECTIVES The aim of this study was to determine which patients will have systolic and diastolic improvement after beta-blockade with metoprolol. BACKGROUND Beta-adrenergic blocking agents improve systolic and diastolic function in patients with heart failure. However, it is unclear which patients will respond best to therapy. METHODS We retrospectively examined baseline characteristics of 24 patients who underwent double-blind then open-label treatment with metoprolol to determine which characteristic predicted improvement in systolic and diastolic function. Degree of improvement in systolic function (22 patients) was defined by the change in left ventricular ejection fraction after 3 months of therapy. Degree of improvement in diastolic function (15 patients) was defined as the change in left ventricular end-diastolic pressure and change in the slope of the isovolumetric relaxation rate-end-systolic pressure relation. RESULTS Both systolic blood pressure at baseline (r = 0.54, p = 0.009) and the maximal positive value of the first derivative of left ventricular pressure with respect to time (peak +dP/dt) at baseline (r = 0.39, p = 0.07) correlated with improvement in ejection fraction after metoprolol treatment. Stepwise logistic regression demonstrated that only peak systolic pressure was an independent predictor of systolic improvement. Baseline heart rate, ventricular volumes, ejection fraction and adrenergic activation, as reflected by coronary sinus norepinephrine, did not predict response. Patients with the most diastolic impairment at baseline had the most favorable diastolic improvement. Those with the lowest myocardial respiratory quotient (most fatty acid utilization) at baseline also had the most marked reduction in left ventricular end-diastolic pressure. CONCLUSIONS These data suggest that those patients with the highest peak systolic pressure, highest left ventricular end-diastolic pressure and most prolonged isovolumetric relaxation at baseline will respond best to therapy with metoprolol. However, other patients without these characteristics may also benefit.


Journal of Neuropathology and Experimental Neurology | 1998

Neocortical Synapse Density and Braak Stage in The Lewy Body Variant of Alzheimer Disease: A Comparison with Classic Alzheimer Disease and Normal Aging.

Daniel F. Brown; Richard C. Risser; Eileen H. Bigio; Patrick Tripp; Ashley Stiegler; Erin Welch; Kathleen P. Eagan; Christa L. Hladik; Charles L. White

Abstract. Substantial numbers of cortical and subcortical Lewy bodies are seen in approximately one quarter of patients whose brains show sufficient histopathologic changes for a neuropathologic diagnosis of definite Alzheimer disease (AD). This subset of cases has been named the Lewy body variant of AD (LBV). Despite comparable dementia and the presence of neocortical senile plaques in LBV patients, the overall burden of neuropathologic changes, in particular neurofibrillary tangles (NET), is less than in classic AD. While NFT frequency correlates with dementia severity in classic AD, the cognitive impairment in patients with LBV cannot be completely explained by such changes. Since several studies have suggested a role for synapse loss in relation to dementia severity in classic AD, we decided to investigate the role of synapse loss as a candidate for the cognitive impairment of LBV. The Braak staging method is based upon the distribution and severity of neurofibrillary changes, and one therefore would expect LBV cases to be assigned to lower Braak stages. In the present study we assigned a Braak stage to 14 LBV cases, 31 classic AD cases, and a group of 10 non-demented aged controls. We compared the severity of synapse loss as determined by ELISA immunoassay for synaptophysin and Braak stage among the three diagnostic groups. When compared to normal controls, synaptophysin concentrations were statistically significantly lower in both demented groups. There was comparable synapse loss in LBV and AD despite significantly lower Braak stages in the LBV cases. These results suggest a major role for loss of synapses as the substrate of cognitive impairment in LBV.


Journal of Clinical Psychopharmacology | 2003

Acute dysphoric mania: treatment response to olanzapine versus placebo.

Robert W. Baker; Mauricio Tohen; Jan Fawcett; Richard C. Risser; Leslie M. Schuh; Eileen Brown; Virginia L. Stauffer; Lixin Shao; Gary D. Tollefson

A substantial number of patients with mania have significant concomitant depressive features, and they may respond differently to mood stabilizers than patients with pure mania. This post-hoc analysis explored the response characteristics of olanzapine versus placebo in bipolar I manic patients with dysphoric and nondysphoric mania (differentiated by baseline Hamilton Depression Rating Scale [HAM-D] score of >20). Two similar, double-blind, randomized trials comparing olanzapine, 5–20 mg, to placebo were pooled for these analyses (N = 246). Mean changes in Young-Mania Rating Scale (Y-MRS) and HAM-D scores during 3 weeks of treatment were examined. Twenty-eight percent of patients had dysphoric mania (olanzapine, n = 33; placebo, n = 35). Among these patients, olanzapine-treated patients had greater improvement within 1 week than did placebo-treated patients on both mania ratings (Y-MRS: −9.7 vs. −3.0 points;p = 0.011) and depressive symptom ratings (HAM-D: −9.9 vs. −5.4 points;p = 0.025). Among those manic subjects without prominent depressive symptoms (olanzapine, n = 91; placebo, n = 87), mean Y-MRS improvement from baseline to endpoint with olanzapine (−11.5 points) versus placebo (−6.13 points) was comparable to the improvement seen with olanzapine versus placebo in the dysphoric mania subgroup (p = 0.476, test of interaction). In acutely ill manic patients with significant depressive symptoms, olanzapine demonstrated a broad spectrum of efficacy, effectively treating both manic and depressive symptoms. The magnitude of the antimanic response appears similar, regardless of baseline depressive features. Additional experience with putative mood stabilizers and atypical agents in mixed mania should include an exploration of their efficacy in treating both manic and depressive mood symptoms.


Journal of Neuropathology and Experimental Neurology | 1995

Neuropathologic evidence that the lewy body variant of Alzheimer disease represents coexistence of Alzheimer disease and idiopathic Parkinson disease

Daniel F. Brown; M. A. Dababo; Eileen H. Bigio; Richard C. Risser; Kathleen P. Eagan; Christa L. Hladik; Charles L. White

We undertook this study to investigate the neuropathologic relationships among Alzheimer disease (AD), idiopathic Parkinson disease (PD), and the Lewy body variant of AD (AD/LBV). We retrieved 30 autopsy cases in which Lewy bodies (LB) had been identified in the substantia nigra (SN) in routine hematoxylin-eosin-stained sections. Twenty-two of the cases had a primary clinical diagnosis of dementia and neuropathologic changes of AD; 12 of these demented patients also had clinical parkinsonism. Eight cases had clinical and neuropathologic evidence of PD with minimal or no AD neuropathology, though 6 had clinical dementia. Controls consisted of 6 cases of AD without SN LB by hematoxylin-eosin, and 5 neurologically normal aged controls. Paraffin sections of SN, superior temporal gyrus, and cingulate gyrus from each case were immunostained with rabbit anti-ubiquitin antiserum, randomized, and analyzed individually by light microscopy, and the density of LB-like profiles in each section were graded. None of 5 nondemented aged controls showed any neocortical LB, even though 2 had significant numbers of incidental SN LB by ubiquitin immunostaining. Of 6 AD cases without SN LB by hematoxylin-eosin, 3 had rare SN LB on ubiquitin stain, 1 of which showed rare neocortical Lewy-like profiles. Seven of 8 PD cases showed neocortical LB, including the 6 with dementia. Twenty-one of 22 AD cases with SN LB showed ubiquitin-immunoreactive Lewy-like bodies in the neocortex that were statistically significantly greater in number than in either pure PD or pure AD cases. The frequent occurrence of LB in the neocortex in PD alone suggests that AD/LBV likely represents mixed AD/PD. However, AD neuropathology may favor or promote the formation of neocortical LB in patients who go on to develop mixed AD/PD pathology.


The American Journal of the Medical Sciences | 1995

Effects of Cocaine on Cortisol Secretion in Humans

Christian M. Heesch; Brian H. Negus; Richard W. Snyder; Eric J. Eichhorn; Joseph H. Keffer; Richard C. Risser

The effects of acute cocaine administration on the pituitary adrenal axis in humans without a history of drug abuse are unknown. The authors studied 12 male volunteers twice in a double-blinded, placebo-controlled, randomized fashion. After intranasal administration of 2 mg/kg cocaine, cortisol levels were significantly higher than after placebo administration. The authors concluded that acute administration of cocaine to humans increases cortisol secretion.


Mayo Clinic Proceedings | 2011

Duloxetine, Pregabalin, and Duloxetine Plus Gabapentin for Diabetic Peripheral Neuropathic Pain Management in Patients With Inadequate Pain Response to Gabapentin: An Open-Label, Randomized, Noninferiority Comparison

Robert J. Tanenberg; Gordon A. Irving; Richard C. Risser; Jonna Ahl; Michael J. Robinson; Vladimir Skljarevski; Sandra K. Malcolm

OBJECTIVE To determine whether duloxetine is noninferior to (as good as) pregabalin in the treatment of pain associated with diabetic peripheral neuropathy. PATIENTS AND METHODS We performed a 12-week, open-label study of patients with diabetic peripheral neuropathic pain who had been treated with gabapentin (≥ 900 mg/d) and had an inadequate response (defined as a daily pain score of ≥ 4 on a numerical rating scale [0-10 points]). The first patient was enrolled on September 28, 2006, and the last patient visit occurred on August 26, 2009. Patients were randomized to duloxetine monotherapy (n=138), pregabalin monotherapy (n=134), or a combination of duloxetine and gabapentin (n=135). The primary objective was a noninferiority comparison between duloxetine and pregabalin on improvement in the weekly mean of the diary-based daily pain score (0- to 10-point scale) at end point. Noninferiority would be declared if the mean improvement for duloxetine was no worse than the mean improvement for pregabalin, within statistical variability, by a margin of -0.8 unit. RESULTS The mean change in the pain rating at end point was -2.6 for duloxetine and -2.1 for pregabalin. The 97.5% lower confidence limit was a -0.05 difference in means, establishing noninferiority. As to adverse effects, nausea, insomnia, hyperhidrosis, and decreased appetite were more frequent with duloxetine than pregabalin; insomnia, more frequent with duloxetine than duloxetine plus gabapentin; peripheral edema, more frequent with pregabalin than with duloxetine; and nausea, hyperhidrosis, decreased appetite, and vomiting, more frequent with duloxetine plus gabapentin than with pregabalin. CONCLUSION Duloxetine was noninferior to pregabalin for the treatment of pain in patients with diabetic peripheral neuropathy who had an inadequate pain response to gabapentin. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00385671.

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Mauricio Tohen

University of New Mexico

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Joseph R. Calabrese

Case Western Reserve University

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Myron F. Weiner

University of Texas Southwestern Medical Center

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Charles L. Bowden

University of Texas Health Science Center at San Antonio

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Charles L. White

University of Texas Southwestern Medical Center

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