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Biomedical subjects

L B Goldstein

Publications and source records attributed to L B Goldstein.

At least 91 records · Page 5Linked to original sources
PubMed1993

Predicting complications of carotid endarterectomy.

BACKGROUND AND PURPOSE: Carotid endarterectomy has been shown to be beneficial in patients with high-grade carotid stenosis and ipsilateral transient ischemic attack or stroke. This benefit will be realized only if the operation is performed safely. We sought to determine the extent to which clinically significant adverse events occurring after carotid endarterectomy can be predicted from clinical data available before surgery. METHODS: Eleven hundred sixty patients were randomly selected from all patients who underwent carotid endarterectomy and were discharged during the calendar years 1988, 1989, and 1990 in 12 academic medical centers in 10 states. Clinical data abstracted from hospital charts were analyzed retrospectively. A model was developed and validated to predict the occurrence of stroke, myocardial infarction, or death during the postoperative period of hospitalization. RESULTS: Eight patients (6.9%) suffered at least one adverse event. Rates for individual complications were as follows: death, 1.4%; nonfatal stroke, 3.4%; nonfatal myocardial infarction, 2.1%; and nonfatal stroke or death, 4.8%. Significant predictors of adverse events were age 75 years or older, symptom status (ipsilateral symptoms versus asymptomatic or nonipsilateral symptoms), severe hypertension (preoperative diastolic blood pressure of greater than 110 mm Hg), carotid endarterectomy performed in preparation for coronary artery bypass surgery, history of angina, evidence of internal carotid artery thrombus, and internal carotid artery stenosis near the carotid siphon. The presence of two or more of these risk factors was associated with a nearly twofold increase in risk of an adverse event (relative risk, 1.7; 95% confidence interval, 1.0 to 3.0). CONCLUSIONS: Clinical data can be used to stratify patients undergoing carotid endarterectomy according to risk of postoperative in-hospital stroke, myocardial infarction, or death.

Aged↗
PubMed1992

Post-lesion administration of the NMDA receptor antagonist MK-801 does not impair motor recovery after unilateral sensorimotor cortex injury in the rat.

Although treatment with N-methyl-D-aspartate (NMDA) receptor antagonists reduce neuronal loss after cerebral infarction and brain trauma in laboratory animals, there is little data concerning the effects of these drugs on behavioral recovery. Because NMDA receptor antagonists impede certain kinds of learning, and because motor recovery after sensorimotor cortex injury in the rat is dependent on post-lesion experience, we hypothesized that treatment with MK-801 after focal brain injury would be detrimental. Groups of rats were first trained to traverse a narrow elevated beam and then subjected a right sensorimotor cortex suction-ablation lesion. In the first experiment, 24 h later, each rat received a single dose of either saline or the NMDA receptor antagonist MK-801 (0.5, 1.0, or 2.0 mg/kg). Beam-walking recovery was measured over the next 12 days. In a second experiment, rats were given 3 doses of MK-801 (0.5 mg/kg) at 24 h intervals beginning 24 h after cortex injury. In a third experiment, lesioned and sham-operated rats were allowed to recover for 12 days and then given MK-801 (0.5 mg/kg). Despite obvious behavioral effects of the drug, there was no overall difference in beam-walking performances among the treatment groups in any of the experiments. If 're-learning' is involved in motor recovery after cortex injury, the present results suggest that the process is not susceptible to permanent disruption by the early or late administration of an NMDA receptor antagonist.

Animals↗
PubMed1992

Early recurrent ischemic stroke. A case-control study.

BACKGROUND AND PURPOSE: Data concerning potentially treatable risk factors for early recurrent stroke are limited. Therefore, we carried out a retrospective case-control study to identify factors predisposing to early reinfarction. SUMMARY OF REVIEW: We identified all patients admitted to Duke University Hospital or the Durham Veterans Administration Medical Center during 1 year having two documented ischemic strokes within 90 days (n = 12 of 273). Twelve randomly selected patients matched for age, sex, and race but having only a single stroke served as controls. There were no significant differences between the groups with respect to a variety of factors including the presence of hypertension, diabetes, a history of transient ischemic attack, a history of stroke, cerebral site of the index stroke, and subtype of the index stroke. A potential cardioembolic source was more frequently identified in the patients with early recurrent stroke (seven of the 12 case-control pairs were discordant for a potential cardioembolic source; McNemar's chi 2 test, p less than or equal to 0.02). CONCLUSIONS: Of the variables examined, the presence of a potential cardioembolic source was the single statistically significant factor associated with reinfarction within the first 90 days after ischemic stroke. The limitations and possible therapeutic implications of these results are discussed.

Aged↗
PubMed1992

Measurement of motor recovery after stroke. Outcome assessment and sample size requirements.

BACKGROUND AND PURPOSE: The purpose of this study was to analyze recovery of motor function in a cohort of patients presenting with an acute occlusion in the carotid distribution. Analysis of recovery patterns is important for estimating patient care needs, establishing therapeutic plans, and estimating sample sizes for clinical intervention trials. METHODS: We prospectively measured the motor deficits of 104 stroke patients over a 6-month period to identify earliest measures that would predict subsequent motor recovery. Motor function was measured with the Fugl-Meyer Assessment. Fifty-four patients were randomly assigned to a training set for model development; 50 patients were assigned to a test set for model validation. In a second analysis, patients were stratified on basis of time and stroke severity. The sample size required to detect a 50% improvement in residual motor function was calculated for each level of impairment and at three points in time. RESULTS: At baseline the initial Fugl-Meyer motor scores accounted for only half the variance in 6-month motor function (r2 = 0.53, p less than 0.001). After 5 days, both the 5-day motor and sensory scores explained 74% of the variance (p less than 0.001). After 30 days, the 30-day motor score explained 86% of the variance (p less than 0.001). Application of these best models to the test set confirmed the results obtained with the training set. Sample-size calculations revealed that as severity and time since stroke increased, sample sizes required to detect a 50% improvement in residual motor deficits decreased. CONCLUSIONS: Most of the variability in motor recovery can be explained by 30 days after stroke. These findings have important implications for clinical practice and research.

Activities of Daily Living↗
PubMed1991

Recurrent transient ischemic attacks and stroke in association with an internal carotid artery web.

Fibromuscular dysplasia is a nonatherosclerotic vascular disease that most commonly affects cervical carotid arteries at the C1-C2 level when cephalic arteries are involved. Several histopathologic and angiographic subtypes of fibromuscular dysplasia exist; most have a benign natural history. We describe the third reported case of a pathologically proven, symptomatic proximal internal carotid artery web and suggest that patients with this lesion are at a higher risk for stroke.

Adult↗
PubMed1990

Clonidine impairs recovery of beam-walking after a sensorimotor cortex lesion in the rat.

Beam-walking in the rat is a useful model for studying the effects of drugs on motor recovery following brain injury. In the present experiment, the effect of clonidine HCl on beam-walking recovery was investigated. Groups of rats were first trained to traverse a narrow elevated beam and then subjected to a right sensorimotor cortex suction-ablation injury. After 24 h, each rat received a single dose of clonidine HCl (20, 60, or 200 micrograms/kg, i.p., salt weight) or saline. Recovery of beam-walking ability was scored over the next 12 days. Treatment with clonidine significantly slowed the rate of recovery (Kruskal-Wallis H = 8.755, df = 3; 0.02 less than P less than 0.05). Furthermore, the impairment persisted for at least 5 days after the rats were treated (Kruskal-Wallis H = 8.47, df = 3; 0.02 less than P less than 0.05). These data are consistent with the hypothesis that norepinephrine, working through central alpha 2-adrenergic receptors, influences motor recovery after a unilateral sensorimotor cortex lesion in the rat. Since many stroke patients are treated with centrally acting antihypertensive drugs, the potential effects of specific classes of these drugs during the recovery period, should be carefully considered.

Animals↗
PubMed1990

Beam-walking in rats: studies towards developing an animal model of functional recovery after brain injury.

While it has long been recognized that humans recover function after stroke or head injury, the direct impact of drugs on recovery has only recently received attention. The ability of rats to traverse a narrow, elevated beam has proven to be particularly useful when studying the effects of pharmacologic manipulations on motor recovery following cortical injury. However, the effect of testing conditions on the recovery of beam-walking performance has not been investigated. Treatment with amphetamine facilitated recovery of beam-walking following cortical lesions regardless of whether 'massed' or 'spaced' trials were employed. Unexpectedly, the performance of sham-operated controls declined when tested with 'massed' trials. 'Prodding' sham-operated rats by tapping on the rump abolished this decline in performance, but resulted in enhanced recovery in lesioned animals. The results indicate that testing conditions can exert a significant influence on beam-walking performance and are important to consider when interpreting the impact of pharmacologic agents on the recovery process.

Amphetamines↗
PubMed1990

Influence of lesion size and location on amphetamine-facilitated recovery of beam-walking in rats.

Amphetamine treatment facilitates recovery of beam-walking in rats with unilateral sensorimotor cortex lesions. Lesion extent was studied in amphetamine- and saline-treated rats selected for rapid and slow recoveries. Lesion volume, lesion depth, and the amount of medial cortex damage were not different among the 4 groups of rats. When the data were analyzed without regard to drug treatment, both lesion depth in rostral forebrain and maximum amount of medial cortex damage negatively correlated with recovery rate. Thus, lesion extent influences the rate of recovery of beam-walking in rats but does not explain the lack of effectiveness of amphetamine in selected animals.

Animals↗
PubMed1990

Large-dose infusions of heparinoid ORG 10172 in ischemic stroke.

We evaluated the safety and possible efficacy of large doses of the heparinoid ORG 10172 in 57 patients with acute or progressing ischemic stroke. Patients received a loading bolus of the drug followed by a maintenance intravenous infusion for 7 days. The plasma level of ORG 10172 was monitored by the degree of inhibition of coagulation factor Xa. In general, the drug was well tolerated and few hemorrhagic complications occurred. Two patients with large cardioembolic hemispheric strokes had intracranial hemorrhagic complications. Most patients improved during treatment. By 3 months after the stroke, 37 patients (65%) had a favorable outcome (minimal or no residual disability). This study suggests that high-dose intravenous infusions of ORG 10172 can be safely given to patients with acute ischemic stroke.

Adolescent↗
PubMed1990

Pharmacology of recovery after stroke.

Laboratory research during the past decade has begun to provide insights into the neurobiologic basis of functional recovery after brain injury. It is clear that drugs influencing specific neurotransmitters also can influence the recovery process. Some of these drugs may be beneficial, but others may be detrimental. Some of the difficulties in interpreting the results of these behavioral studies are reviewed, and potential mechanisms of drug effects are discussed. These types of studies are leading to an increased awareness of the potentially harmful effects of some drugs often given to stroke patients. Pharmacotherapy designed to enhance functional recovery after stroke may be possible in the future.

Amphetamines↗
PubMed1989

Interrater reliability of the NIH stroke scale.

The interobserver reliability of a rating scale employed in several multicenter stroke trials was investigated. Twenty patients who had a stroke were rated with this scale by four clinical stroke fellows. Each patient was independently evaluated by one pair of observers. The degree of interrater agreement for each item on the scale was determined by calculation of the kappa statistic. Interobserver agreement was moderate to substantial for 9 of 13 items. This rating system compares favorably with other scales for which such comparisons can be made. However, the validity of this system must be established.

Cerebrovascular Disorders↗
PubMed1989

A dose escalation study of ORG 10172 (low molecular weight heparinoid) in stroke.

An intravenous infusion of a low molecular weight heparinoid, with a reduced risk of hemorrhage, may be an alternative to heparin in the management of acute ischemic stroke. To evaluate this hypothesis, we studied the safety of the heparinoid, ORG 10172, in a dose-escalation study in 26 patients. The drug was administered as a loading bolus followed by a 7-day infusion in five rates with target anti-factor Xa levels from 0.2 to 1.0 U/ml. The drug was well tolerated; no major bleeding complications or thrombocytopenia occurred. There were no deaths or hemorrhagic transformation of cerebral infarctions. The results indicate that ORG 10172 at doses to achieve a level of 1.0 U/ml or less may be used safely in management of acute cerebral infarction.

Adult↗
PubMed1988

Physician prescribing patterns following hospital admission for ischemic cerebrovascular disease.

Functional recovery after brain injury in laboratory animals is influenced by a variety of drugs. Yet, the impact of currently prescribed drugs on recovery after human stroke remains largely unexplored. From the Duke-VA Stroke Registry, we found 77% of patients admitted to either the university hospital or the Veterans Administration hospital with cerebral infarction were taking medications at the time of their stroke. Ninety-five percent of these patients were receiving medication at the time of discharge. Antihypertensives were the most commonly prescribed agents in the study population, and platelet antiaggregants were second. Sixty-four percent of patients had a change in their antihypertensive regimens. The number of patients prescribed sedative-hypnotic agents doubled over the first 48 hours after hospital admission. The choice of a therapeutic agent for a given clinical indication may have important implications for rehabilitation of the stroke patient.

Aged↗
PubMed1984

Temporomandibular joint repositioning and exercise performance: a double-blind study.

In the present study, the effects of temporomandibular joint (TMJ) repositioning by use of an acrylic appliance on maximum and submaximum physiologic and performance measures were evaluated in seven male and four female volunteers with documented TMJ malalignment. In an attempt to remove design inadequacies of previous research in this area, a double-blind strategy was utilized. Subjects were randomly assigned to each of four conditions: 1) normal, without a bite splint, 2) with a placebo splint with no occlusal contact so as to maintain normal jaw position, 3) with a splint that optimized jaw position, and 4) with a splint that magnified the subjects normal degree of malocclusion. Measurements were taken of visual reaction time and movement time, muscular strength of the grip, elbow flexors, and leg extensors, submaximal and maximal oxygen uptake, perceived exertion, anaerobic power output, and all-out working capacity in both arm and leg exercise on a cycle ergometer. Analysis of variance for repeated measures indicated that in no instance were the differences in mean scores on physiologic and performance measures with TMJ repositioning or placebo statistically significant when compared with the normal condition. This was the case for the group as a whole or when the five subjects with the greatest TMJ dysfunction were analyzed separately. These findings strongly support the contention that the beneficial effects of short-term TMJ repositioning on exercise performance noted in previous reports may be the result of inadequacies in research design and evaluation rather than the true effects of the bite splint.

Adolescent↗
PubMed1977

Construction of low-variability litters of preweaning mice.

Mouse litter variation at weaning stems from a combination of genetic makeup, intrauterine experience, and postnatal maternal care. The 1st 2 factors may be matched at birth by making up separate litters out of littermate pairs whose birth weights are equal (+/-.02 g). Maternal competence may be matched by exchanging the mothers between the 2 cages each day. These tactics yield litters at weaning whose variability has been very much reduced. The range of litter-average body weights has been reduced from about 40 percent to about 5 percent and the range of litter-average brain weights has been reduced from about 15 percent to about 1-2 percent.

Animals↗