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Biomedical subjects

J M Silver

Publications and source records attributed to J M Silver.

At least 19 recordsLinked to original sources

Effects of rivastigmine on cognitive function in patients with traumatic brain injury.

OBJECTIVE: To compare the efficacy and safety of rivastigmine (3 to 6 mg/day) vs placebo over 12 weeks in patients with traumatic brain injury and persistent cognitive impairment. METHODS: This prospective, randomized, double-blind, placebo-controlled study was conducted in 157 patients at least 12 months after injury. The primary efficacy measures were the Cambridge Neuropsychological Test Automated Battery (CANTAB) Rapid Visual Information Processing (RVIP) A' subtest and the Hopkins Verbal Learning Test (HVLT). The primary efficacy outcome was the proportion of patients who demonstrated 1.0 SD or greater improvement from baseline at week 12 on CANTAB RVIP A' or HVLT. RESULTS: The percentage of responders at week 12 on either the CANTAB RVIP A' or HVLT was 48.7% for rivastigmine and 49.3% for placebo (p = 0.940). Furthermore, for the overall study population, there were no significant differences for any of the secondary efficacy variables. In a subgroup of patients with moderate to severe memory impairment (n = 81), defined as 25% impairment or greater on HVLT at baseline, rivastigmine was significantly better than placebo for a number of measures, including the proportion of HVLT responders and CANTAB RVIP mean latency. CONCLUSIONS: Rivastigmine was safe and well tolerated in patients with traumatic brain injury with cognitive deficits. Rivastigmine shows promising results in the subgroup of patients with traumatic brain injury with moderate to severe memory deficits.

Adolescent↗

The association between head injuries and psychiatric disorders: findings from the New Haven NIMH Epidemiologic Catchment Area Study.

PRIMARY OBJECTIVE: To determine the association of report of any history of head injury with loss of consciousness or confusion and a lifetime diagnosis of psychiatric disorder in a general population. RESEARCH DESIGN: A probability sample of adults from the New Haven portion of the NIMH Epidemiologic Catchment Area programme were administered standardized and validated structured interviews. The main outcome measures were lifetime prevalence of psychiatric disorders and suicide attempt in individuals with and without a history of traumatic brain injury. MAIN OUTCOMES AND RESULTS: Among 5034 individuals interviewed, 361 admitted to a history of severe brain trauma with loss of consciousness or confusion (weighted rate of 8.5/100). When controlling for sociodemographic factors, quality of life indicators and alcohol use, risk was increased for major depression, dysthymia, panic disorder, OCD, phobic disorder and drug abuse/dependence. In addition, lifetime risk of suicide attempt was greater in those who had suffered head injury. CONCLUSION: Individuals with a history of traumatic brain injury have significantly higher occurrence for psychiatric disorders and suicide attempts in comparison with those without head injury and have a poorer quality of life. Future studies should examine the nature of this relationship, focusing on the severity of the brain injury and the temporal contiguity of the brain injury and psychiatric disorder.

Adult↗

Axis II psychopathology in individuals with traumatic brain injury.

PRIMARY OBJECTIVES: To determine the frequency and nature of post-TBI personality disorders (PDs) in a community-based sample of individuals with TBI. RESEARCH DESIGN: One hundred individuals with TBI were administered a structural clinical interview to determine Axis II psychopathology. METHODS OF PROCEDURES: The Structured Clinical Interview for DSM-IV Personality Disorders, Clinician Version (SCID II) was used to determine 12 Axis II personality disorders. SCID II questions were modified so that symptom onset could be rated as occurring pre-injury vs. post-TBI. Data were analysed using student T-tests, chi-square analysis and one way analyses of variance. OUTCOMES AND RESULTS: Pre-TBI PDs were diagnosed in 24% of the sample; antisocial PD and obsessive-compulsive PD were the most common diagnoses. Post-TBI, 66% of the sample met criteria for at least one PD, with PDs independent of TBI severity, age at injury, and time since injury. The most common post-TBI PDs were: borderline, avoidant, paranoid, obsessive-compulsive and narcissistic. Men were more likely to be diagnosed with antisocial PD and narcissistic PD. Individuals with pre-TBI PDs were at greater risk of acquiring additional psychopathology post-TBI. Personality traits endorsed by more than 30% of the sample post-TBI reflected loss of self-confidence, attempts to cope with cognitive and interpersonal failures and negative affect. CONCLUSION: These findings argue against a specific TBI personality syndrome, but rather a diversity of personality disorders reflective of the persistent challenges and compensatory coping strategies developed by individuals post-TBI. Prospective need for clinical assessment, pro-active education and focused treatment approaches are discussed.

Adaptation, Psychological↗

Ewing's sarcoma presenting as a posterior mediastinal mass: a lesson learned.

Thoracic vertebral body hemicorpectomy and chest wall resection was performed in a 17-year-old male patient with a posterior mediastinal tumor thought to be neurogenic in origin. No preoperative tissue diagnostic endeavor was made. Final pathologic diagnosis showed this tumor to be Ewing's sarcoma. This communication alerts the thoracic surgeon to the need for definitive diagnosis of posterior mediastinal masses with vertebral body involvement, particularly in children. Induction chemotherapy is the accepted standard of management of these sarcomas.

Adolescent↗

Vasopressin treats the persistent feeling of coldness after brain injury.

In this pilot study, 6 patients who complained of persisting coldness after brain injury were treated with intranasal vasopressin (DDAVP) twice daily for 1 month. Response was assessed after 1 month of treatment, DDAVP was discontinued, and response was reassessed 1 month later. Five of the 6 patients had a dramatic response to DDAVP, as soon as 1 week after initiating treatment, and no longer complained of feeling cold. Response persisted even after discontinuation of treatment. Patients denied any side effects from treatment with DDAVP. The experience of persisting coldness can respond dramatically to brief treatment with intranasal DDAVP. The authors discuss possible mechanisms of action to explain this phenomenon.

Adolescent↗

Propranolol treatment of chronically hospitalized aggressive patients.

Violent behavior in psychiatric patients may result in long-term hospitalization. There is no FDA-approved psychopharmacologic treatment for aggression. In this study, 20 chronically aggressive hospitalized patients were administered 1 week of placebo followed by an open trial of increasing doses of propranolol. Patients who had an equivocal or definite clinical response were entered into an open add-on double-blind discontinuation study phase. Aggressive behavior was objectively documented throughout the study. After the open phase of the study, 7 patients had a greater than 50% decrease in aggressive behavior. Four patients entered the double-blind discontinuation phase. The clinical course of 3 of those patients was consistent with the positive response to propranolol. The results of this study are consistent with a therapeutic effect of propranolol in some patients with aggressive behavior. Further studies are indicated.

Adrenergic beta-Antagonists↗

Laparoscopic-guided biopsy of pancreatic transplant allograft.

UNLABELLED: Percutaneous and transcystoscopic transplanted pancreatic graft biopsy have now become the best methods in diagnosing graft rejection and dysfunction. We report our technique of laparoscopic pancreatic graft biopsy in a case not amenable to standard trancystoscopic or percutaneous biopsy. CASE REPORT: A 44-year-old man underwent enteric conversion of a previous combined bladder-drained kidney-pancreas transplantation for repeated episodes of dehydration. Complaints of polyuria and polydipsia necessitated biopsies of the grafts to rule out graft rejection. The ultrasound of the pancreas, however, showed multiple bowel loops overlying the graft preventing percutaneous biopsy. The patient was taken for laparoscopic-guided pancreatic graft biopsy. DISCUSSION: Enteric-converted pancreatic grafts are not amenable to transcystoscopic biopsy. These grafts are often covered with loops of small bowel preventing ultrasound-guided percutaneous biopsy. Until recently, open laparotomy was performed to biopsy these grafts. We present our method of laparoscopic-guided pancreatic graft biopsy as an alternative to open laparotomy. CONCLUSIONS: Laparoscopic guided biopsy for pancreatic allograft transplantation is a safe and effective alternative to open laparotomy and should be considered when percutaneous biopsy is hazardous or not possible.

Acute Disease↗

The Overt Agitation Severity Scale for the objective rating of agitation.

Two studies tested the reliability and validity of the Overt Agitation Severity Scale (OASS), a new instrument developed to define and objectively rate the severity of agitated behavior. The authors postulate that agitation should be conceptualized as vocal and motor behaviors on a continuum of expressions that extends from anxiety to aggression. Content validity through expert agreement was achieved in the development of test construction over a 2-year period. Results of two pilot studies (n = 25 and n = 14 subjects) established the reliability and validity of the OASS to measure agitation severity. The OASS differs from other agitation scales in that it confines its rating exclusively to observable behavioral manifestations of agitation.

Aged↗

Coronary vasodilation by isoflurane. Abrupt versus gradual administration.

BACKGROUND: Under certain circumstances, isoflurane is associated with coronary artery vasodilation. The objective of the current study was to ascertain whether the rate of administration of isoflurane influences its vasodilating effect in the coronary circulation. METHODS: Seven open-chest dogs anesthetized with fentanyl and midazolam were studied. The left anterior descending coronary artery was perfused via either of two pressurized (80 mmHg) reservoirs; reservoir 1 (control) was supplied with arterial blood free of isoflurane, and reservoir 2 was supplied with blood from an extracorporeal oxygenator, which was provided with 95% O2/5% CO2 gas that passed through calibrated vaporizer. Coronary blood flow (CBF) was measured with Doppler flow transducer. In each dog, isoflurane was administered according to two protocols; abrupt (isoflurane-A) or gradual (isoflurane-G). In isoflurane-A, the left anterior descending coronary artery was switched from reservoir 1 to reservoir 2 after the latter was filled with blood previously equilibrated with 1.4% (1 MAC) isoflurane. In isoflurane-G, the left anterior descending coronary artery was switched to reservoir 2 with vaporizer set at 0% isoflurane; then the vaporizer was adjusted to 1.4% isoflurane, which produced a gradual increase in isoflurane concentration within reservoir 2 that reached a level equivalent to that in isoflurane-A (as evaluated by gas chromatography) by 30 min. CBF during maximally dilating, intracoronary infusion of adenosine served as a reference to assess effects of isoflurane. RESULTS: Isoflurane-A caused marked increases in CBF, which, at constant perfusion pressure, reflected pronounced reductions in vascular resistance. These increases in CBF were 80% of those with adenosine. Although isoflurane-G also caused increases in CBF, the increases were only 45% of those caused by isoflurane-A. CONCLUSIONS: The current findings demonstrate that the extent of coronary vasodilation by isoflurane was not dependent only on its blood concentration but also on the rate at which this blood concentration was achieved; a gradual increase in blood concentration blunted the vasodilator effect. Differences in the rate of administration of isoflurane likely contributed to its widely variable coronary vasodilating effects in previous studies.

Adenosine↗

Contribution of nitric oxide to coronary vasodilation during hypercapnic acidosis.

The present study was performed to evaluate the role of nitric oxide (NO) in coronary vasodilation during hypercapnic acidosis (HC). The left anterior descending coronary arteries of 17 anesthetized, open-chest dogs were perfused with normal arterial blood or with arterial blood equilibrated in an extracorporeal circuit with 90% O2-10% CO2 [arterial carbon dioxide tension (PaCO2) 72 +/- 3 mmHg, arterial pH 7.16 +/- 0.02]. Coronary perfusion pressure (CPP) was initially set at 100 mmHg. Coronary blood flow (CBF) was measured with a Doppler transducer. Studies were conducted under constant-pressure (variable CBF; n = 13) and constant-flow (variable CPP) conditions (n = 4). Steady-state changes in CBF (or CPP) during HC and during intracoronary infusions of acetylcholine (ACh, 20 micrograms/min), an endothelium-dependent vasodilator, and sodium nitroprusside (SNP, 80 micrograms/min), an endothelium-independent vasodilator, were compared before and after intracoronary infusion of a NO synthase inhibitor, either NG-nitro-L-arginine methyl ester (L-NAME, 4.5 mg) or NG-monomethyl-L-arginine (L-NMMA, 30 mg). Under constant pressure, L-NAME blunted increases in CBF by HC (274 +/- 32 vs. 113 +/- 24%) and ACh (400 +/- 43 vs. 68 +/- 17%), whereas increases in CBF by SNP were not significantly affected (207 +/- 34 vs. 186 +/- 18%). Results with L-NMMA were similar. Under constant flow, L-NAME attenuated decreases in CPP by HC and ACh, whereas it had no significant effect on decreases in CPP by SNP. In conclusion, HC elicits release of NO from coronary vascular endothelium via a direct effect rather than secondary to an increased flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

Differences in the anatomic distribution of immediate-early gene expression in amygdala and angular bundle kindling development.

Kindling is a model in which fleeting changes of neuronal activity produce a lifelong modification of neuronal structure and function in the mature nervous system. Immediate-early genes (IEGs) such as c-fos have been implicated as a causal link in the chain of molecular events coupling fleeting pathologic activity to lasting hyperexcitability. Identification of the brain structures exhibiting IEG expression during the evolution of kindling is necessary to guide investigations of the phenotypic consequences. We used in situ hybridization histochemistry to identify the structures exhibiting expression of multiple IEGs during the evolution of amygdala kindling and compared this to the pattern following angular bundle kindling. The principal findings included that: (1) generalized limbic and clonic motor (class 5) kindled seizures evoked by stimulation of one amygdala induced the expression of IEGs in a small subset of limbic structures with remarkable symmetry between the two hemispheres; (2) the anatomic extent of seizure-evoked expression of c-fos mRNA expanded progressively following focal limbic and motor (classes 0-3) seizures during the development of amygdala kindling; c-fos mRNA was detected first ipsilaterally in AM, ACO, and PC and with higher-class seizures in hippocampal formation and homologous structures contralaterally, and (3) class 5 seizures evoked by stimulation of two different sites in the limbic system (amygdala or angular bundle) induced IEG expression in distinct but partially overlapping anatomic structures. We propose that synaptic activation of glutamate receptors contributes to the expression of these diverse IEGs throughout the forebrain. The findings provide a constellation of anatomic structures in which to investigate the structural and functional consequences of IEG expression.

Amygdala↗

Pharmacologic approach to management of agitation associated with dementia.

Dementia is a complex syndrome associated with cognitive impairment, personality change, and behavioral disturbance. Behavioral symptoms frequently present the greatest challenge for caregivers and are often the determining factor in institutional placement. Determining the need for pharmacologic treatment of an agitated patient requires considering the full range of biopsychosocial variables and ultimately involves assessing the risks and benefits of the medications selected for the patient. In this article, the phenomenology of agitation is reviewed along with the pharmacologic treatment of agitation in patients with dementia, including the use of benzodiazepines, neuroleptics, beta-adrenergic-blocking agents, serotonergic agents, carbamazepine, and lithium.

Adrenergic beta-Antagonists↗

Neuropsychiatric aspects of adult-onset Tay-Sachs disease: two case reports with several new findings.

Deficiency of hexosaminidase A causes the GM2 gangliosidosis known as Tay-Sachs disease. It is now known that this condition has several late-onset variants that cause numerous neuropsychiatric disturbances. Early recognition is important because treatment with phenothiazines and heterocyclic antidepressants may worsen the course. The authors report two cases with several new findings, including prominent psychiatric symptoms without psychosis early in the course of the illness.

Adult↗

Pharmacological and behavioral treatments for aggressive psychiatric inpatients.

OBJECTIVE: Because aggressive behaviors of psychiatric patients may be caused by environmental or biological factors, treatment plans that incorporate medication and behavior therapies are the most effective. The authors review research on pharmacological and behavioral treatments for aggressive patients and present a decision tree for use on behavioral units to direct treatment of such patients. METHODS: The empirical literature was searched for studies of pharmacological and behavioral interventions that have been shown to have some value for treating this problem. RESULTS AND CONCLUSIONS: Psychiatrists must proceed cautiously because no medication has been approved by the Food and Drug Administration specifically for treatment of aggression. Antipsychotics, lithium, antidepressants, sedatives, anxiolytics, anticonvulsants, opiate antagonists, and beta blockers have been used, often depending on the etiology of the aggression, such as head injury or dementia. Although some drugs such as buspirone and propranolol show promise; side effects must be monitored. Three behavioral strategies have effectively reduced aggression in the inpatient milieu. The token economy is perhaps the most comprehensive behavioral tool for producing a well-structured milieu. Aggression replacement strategies help patients learn alternative responses. Decelerative techniques teach strategies that enable the patient to reduce aggression quickly. The authors describe a decision tree to guide decisions about pharmacological and behavioral treatments of aggression depending on where in the course of the disorder patients exhibit difficulty.

Aggression↗

Cocaine and aggressive behavior: neurobiological and clinical perspectives.

Irritability, angry affect, and aggressive behavior are commonly associated with cocaine abuse. The authors describe neurobiological mechanisms that may explain this association. They also recommend guidelines for the assessment and treatment of patients who display cocaine-related aggressive activity.

Aggression↗

Antiepileptogenic effects of conventional anticonvulsants in the kindling model of epilespy.

We sought to determine whether the clinically effective anticonvulsant drug valproate exhibited antiepileptogenic properties in the kindling model (we use the term anticonvulsant to mean suppression of seizure, and antiepileptogenic to mean suppression of development of epilepsy). We compared and contrasted valproate with two other anticonvulsant drugs, phenobarbital and carbamazepine. We investigated the effects of these drugs on the development of kindling, that is, the number of stimulation-induced afterdischarges required to induce enhanced seizure susceptibility in rats. Valproate exhibited powerful antiepileptogenic effects as evident in a dose-dependent increase in the number of afterdischarges required to induce kindling. These effects were not due to retained valproate or an active metabolite merely masking the expression of kindled seizures. By contrast, carbamazepine was devoid of any antiepieptogenic effects despite exhibiting marked anticonvulsant effects. Like valproate, phenobarbital exhibited both antiepileptogenic and anticonvulsant properties, but its antiepileptogenic properties were significantly less pronounced. The antiepileptogenic effects of valproate and phenobarbital strengthen the candidacy of these agents for the clinical studies needed to investigate pharmacological prevention of the development of epilepsy in high-risk groups.

Action Potentials↗