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Biomedical subjects

R E Kelley

Publications and source records attributed to R E Kelley.

At least 19 recordsLinked to original sources
PubMed2000

Hyperkinetic movement disorders caused by corpus striatum infarcts: brain MRI/CT findings in three cases.

Three patients with hemichorea/hemiballismus/hemidystonia caused by discrete contralateral infarction of the corpus striatum are presented. The infarcts were all small on CT or MRI brain scan and were lacunar in type. Small discrete infarction of basal ganglionic structures allows such adventitious movements to be manifested. Involvement of contiguous areas, seen with larger infarcts, can suppress such movements. The infrequency of such hyperkinetic movement disorders, and the subtle infarct appearance on brain scan, can lead to a delay in the diagnosis.

Adult↗
PubMed2000

Thrombolytic therapy for acute ischemic stroke.

Thrombolytic therapy with recombinant tissue plasminogen activator (rt-RA) is now an accepted treatment for acute ischemic stroke if the patient can be treated within 3 hours of onset of symptoms, and if the clinical presentation justifies use of the medication, and if there are no contraindications to the use of rt-PA. The non-contrast CT brain scan is mandatory to rule out an intracerebral hemorrhage, evidence of subarachnoid hemorrhage, or significant evolution of a large cerebral infarction. The later the patient is treated, within the 3-hour therapeutic window, the less likely there is to be clinical benefit of the treatment and the greater risk of hemorrhagic transformation of the cerebral infarction with potentially catastrophic consequences. There is approximately a 30% greater chance of full recovery from the stroke, at 3 months out from the infarct, with rt-PA compared to no rt-PA. On the other hand, there is a 6.4% risk of symptomatic intracerebral hemorrhage, within 36 hours, associated with the use of rt-PA compared to a 0.6% risk in the placebo group. The greater the neurological deficit at the time of presentation and the greater the evolution of the infarct by the admission CT brain scan, the greater the risk of intracerebral hemorrhage complicating the use of rt-PA.

Acute Disease↗
PubMed1998

Stroke prevention and intervention. New options for improved outcomes.

Data from recent clinical studies have replaced the empiricism that once pervaded the medical literature regarding stroke. This has created exciting opportunities for optimal management as well as challenges related to the importance of early recognition and intervention. Dr Kelley reviews recent advances in prevention and treatment of stroke and describes a systematic approach that directly affects choice of diagnostic tests and therapeutic options.

Acute Disease↗
PubMed1996

Ultrasound densitometric analysis of carotid plaque composition. Pathoanatomic correlation.

BACKGROUND AND PURPOSE: The components of a carotid artery plaque might affect the risk of ipsilateral stroke. The accuracy of carotid duplex scan in assessing stroke risk reflects the experience of the scan reader. Thus, methods that can enhance ultrasonic evaluation of plaque morphology might allow a more objective means of determining carotid-mediated stroke risk. METHODS: We performed densitometric analysis of B-mode images of carotid plaques in nine patients scheduled for carotid endarterectomy. All patients had preoperative duplex color imaging and cerebral arteriography. The surgical specimen was analyzed histologically to determine the plaque components (soft plaque/organized thrombus, intraplaque hemorrhage/lipid deposition, fibrosis, and calcification). The specimen findings were correlated with the densitometric measurements to determine whether the density analysis would allow a reliable determination of the plaque substratum. RESULTS: With 1.0 as a reference point for the moving column of blood, the mean acoustic densities (+/-SD) were as follows: organized thrombus, 1.8 +/- 0.5; intraplaque hemorrhage/lipid deposition, 5.15 +/- 0.9; fibrosis, 9.51 +/- 2.9; and calcification, 15.5 +/- 8.6. CONCLUSIONS: We conclude that densitometric evaluation allows differentiation of the various possible components of carotid plaque. The determination of plaque composition, based on density measurement, may provide information about its potential for thromboembolization.

Aged↗
PubMed1996

Neurosonology in clinical practice.

The role of ultrasound in the diagnosis of cerebrovascular disease is reviewed and is compared with other existing vascular imaging modalities. The present and future role of neurosonology is discussed including transcranial Doppler and carotid Doppler duplex ultrasound.

Arterial Occlusive Diseases↗
PubMed1996

Blood pressure management in acute stroke.

Hypertension is the major risk factor for stroke. When patients present with an acute stroke of ischemic or hemorrhagic type, and have elevated blood pressure, there is a dilemma concerning blood pressure reduction. If the blood pressure remains elevated, this may worsen arterial blood vessel wall injury and increase cerebral edema; however if blood pressure is reduced, this may reduce cerebral perfusion pressure and worsen neurological deficit. A review of the existing literature on this controversial issue is presented.

Cerebral Hemorrhage↗
PubMed1995

Cerebrospinal fluid and peripheral white blood cell response to acute cerebral ischemia.

We prospectively evaluated the inflammatory response to acute cerebral ischemia in 57 patients who were seen within 72 hours of ictus. All subjects had cerebrospinal fluid examination, complete blood count, sedimentation rate determination, and body temperature monitoring. Correlation analysis was done between these measurements and infarct volume, which was determined by computed tomography of the brain. We found a positive linear correlation between infarct size and the peripheral white blood cell count, specifically the polymorphonuclear leukocyte count. A relationship was also observed for the cerebrospinal fluid protein level, the gamma globulin level, and the cerebrospinal fluid/serum albumin ratio. The correlations observed presumably reflect the extent of tissue injury and secondary inflammatory response in acute cerebral ischemia.

Acute Disease↗
PubMed1995

Relation between blood pressure and outcome in intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Controversy continues to exist regarding optimal blood pressure control in acute hypertensive intracerebral hemorrhage. Persistent marked elevation of the blood pressure can promote further bleeding, increase cerebral blood flow, and raise intracranial pressure. Relative hypotension, on the other hand, may promote hypoperfusion with secondary ischemia. This study was designed to assess outcome in patient groups defined by the degree of elevation in their pretreatment and posttreatment blood pressures. METHODS: We retrospectively assessed 87 patients who were categorized according to an initial mean arterial pressure > 145 mm Hg (n = 34) compared with those with a pressure < or = 145 mm Hg (n = 53). We also studied blood pressure control within the first 2 to 6 hours of presentation with subjects categorized according to a mean arterial pressure > 125 mm Hg (n = 40) or < or = 125 mm Hg (n = 47). RESULTS: An improved outcome in both mortality and severe morbidity was observed in the < or = 145 (chi 2 = 7.0, P < .005) and the < or = 125 mm Hg (chi 2 = 6.7, P < .005) groups. CONCLUSIONS: Markedly elevated blood pressure on admission and persistent inadequate blood pressure control adversely affect the prognosis in hypertensive intracerebral hemorrhage.

Adult↗
PubMed1995

Safety, tolerability, and pharmacokinetics of the N-methyl-D-aspartate antagonist dextrorphan in patients with acute stroke. Dextrorphan Study Group.

BACKGROUND AND PURPOSE: Dextrorphan hydrochloride is a noncompetitive N-methyl-D-aspartate antagonist that is neuroprotective in experimental models of focal brain ischemia. The purpose of this study was to determine the maximum loading dose and maintenance infusion of dextrorphan hydrochloride that are well tolerated in patients with an acute stroke. METHODS: An intravenous infusion of dextrorphan or placebo was begun within 48 hours of onset of a mild-to-moderate hemispheric stroke. Initially, patients were treated with either placebo (n = 15) or dextrorphan (n = 22) using a 1-hour loading dose (60 to 150 mg) followed by a 23-hour ascending-dose maintenance infusion (maximum total dose, 3310 mg). Subsequently, 29 patients were treated with dextrorphan in an open trial using a 1-hour loading dose (145 to 260 mg) followed by an 11-hour constant rate (30 to 70 mg/h) infusion. RESULTS: Transient and reversible adverse effects, including nystagmus, nausea, vomiting, somnolence, hallucinations, and agitation, commonly occurred in dextrorphan-treated patients. Loading-dose escalation was stopped because of rapid-onset, reversible, symptomatic hypotension in 7 of 21 patients treated with doses of 200 to 260 mg/h. At the highest rates of maintenance infusion (> 90 mg/h), 3 patients developed deep stupor or apnea. The maximum tolerated loading dose was 180 mg/h, and the maximum tolerated maintenance infusion was 70 mg/h. Maximum plasma levels of 750 to 1000 ng/mL were obtained in 9 patients. There was no difference in neurological outcome at 48 hours between the dextrorphan-treated and placebo-treated patients. CONCLUSIONS: The highest doses of dextrorphan administered were associated with serious adverse experiences in some patients. Lower doses (loading doses of 145 to 180 mg, maintenance infusions of 50 to 70 mg/h) were better tolerated and rapidly produced potentially neuroprotective plasma concentrations of dextrorphan. These doses were associated with well-defined pharmacological effects compatible with N-methyl-D-aspartate receptor antagonism.

Acute Disease↗
PubMed1995

Acute leukocyte and temperature response in hypertensive intracerebral hemorrhage.

BACKGROUND AND PURPOSE: We undertook this study to investigate the relationship between outcome, hematoma volume, and admission peripheral white blood cell count and body temperature in acute hypertensive intracerebral hemorrhage. METHODS: Eighty-two consecutive patients who presented with hypertensive intracerebral hemorrhage within 72 hours of onset were retrospectively assessed. The peripheral white blood cell count, polymorphonuclear leukocytes, and the body temperature on admission were measured. The outcome at 30 days after ictus was determined with a modified Glasgow Outcome Scale. Correlation analysis was performed between these measurements and hematoma volume, which was calculated by brain computed tomography. We also looked at the presence or absence of intraventricular extension. RESULTS: The mean hematoma volume was significantly greater in those patients who died compared with those with a good, moderate, and severe outcome (79.6 cm3 versus 10.7, 18.3, and 19.9 cm3, respectively; P < .0005). The mean peripheral white blood cell count was higher in those who died than in the other three groups (12.580 +/- 0.521 versus 8.160 +/- 0.543, 8.565 +/- 0.543, and 7.427 +/- 0.786 x 10(9)/L, respectively; P < .0005). The mean body temperature of those who died tended to be higher than those in the good-outcome group (99.12 +/- 0.21 versus 98.18 +/- 0.21 degrees F, P < .05). A positive linear correlation was observed between hematoma volume and white blood cell count (r = .506, df = 77, P < .001), as well as the polymorphonuclear leukocyte count (r = .561, df = 76, P < .001). A trend was also observed for admission temperature (r = .265, df = 74, P < .05). The leukocyte response was enhanced by the presence of intraventricular extension. CONCLUSIONS: There is a relationship between the size of the hematoma and the degree of leukocytosis in hypertensive intracerebral hemorrhage. This relationship appears to most likely represent a stress-induced reaction of the white blood cell count.

Aged↗
PubMed1994

Unmasking a patent foramen ovale during recurrent paradoxical cerebral embolism.

A patient with an acute ischemic stroke had an interatrial septal aneurysm shown by transesophageal echocardiography. Interatrial shunting, compatible with a patent foramen ovale, was observed on a follow-up study after a second stroke. This was seen in association with a right atrial thrombus. This case illustrates that an interatrial septal aneurysm serves as a marker for potential interatrial shunting, which can lead to paradoxical cerebral embolism.

Cerebral Infarction↗
PubMed1993

Elevated platelet microparticles in transient ischemic attacks, lacunar infarcts, and multiinfarct dementias.

Platelets release microparticles (PMP) upon activation. Elevated levels of PMP were observed in patients with immune thrombocytopenic purpura (ITP), sometimes associated with a syndrome resembling transient ischemic attack (TIA), suggesting a thrombogenic potential for PMP. To determine if this association applies to TIA and other cerebrovascular accidents (CVA) without ITP, we studied PMP profiles in 71 patients with ischemic CVA: 28 with small vessel CVA (SCVA), either lacunar infarcts or TIA; 24 with large vessel CVA (LCVA); 19 with multiinfarct dementia (MID); 12 with Alzheimer's dementia (AD); and 31 healthy controls. The mean PMP values were: MID = 3.71 +/- 0.51; SCVA = 3.48 +/- 0.63; LCVA = 1.97 +/- 0.28; AD = 1.19 +/- 0.27; controls = 0.88 +/- 0.09, (all units x 10(7)/mL). PMP values in all groups except AD were significantly above normal (p < 0.01). However, the elevation in SCVA was more marked than in LCVA (p < 0.01). Administration of the calcium channel blocker, nifedipine, to 11 TIA patients reduced PMP significantly.

Adult↗
PubMed1993

Selective increase in the right hemisphere transcranial Doppler velocity during a spatial task.

Transcranial Doppler ultrasonography of the middle cerebral arteries was performed during two tasks: sorting of mah-jongg tiles and vibratory stimulation. These tasks selectively increase cerebral blood flow by positron emission tomography. The purpose of this study was to determine if analogous increases in cerebral blood flow velocity could be detected. We measured flow velocity during right hand manipulation followed by left hand manipulation, or vice versa, with resting studies in between. The average increase in the mean velocity, by paired t-test, was significant for the right middle cerebral artery with both left hand (p < .0005) and right hand (p < .005) tile sorting. For the left middle cerebral artery, there was an increase in the mean velocity with right hand (p < .005) but not for left hand sorting (p = .13). These findings support the importance of the right hemisphere in the performance of this type of spatial task. No significant flow velocity increase occurred during vibratory stimulation.

Adult↗
PubMed1993

Sensitivity and specificity of transcranial Doppler ultrasonography in the detection of high-grade carotid stenosis.

We evaluated the ability of transcranial Doppler ultrasonography (TCD) of the middle cerebral artery to detect internal carotid artery luminal area stenosis of 70% or greater by comparing TCD with cerebral angiography in 79 subjects, including 22 with normal cerebral arteriograms and 57 with 30% to 100% internal carotid artery stenosis on at least one side. Of six TCD measurements assessed, the flow acceleration provided the greatest sensitivity (82%) and specificity (73%) in distinguishing 70% to 100% carotid stenosis from lesser degrees of stenosis. The overall accuracy of the flow acceleration was 78%, and the positive predictive value was 79%. A flow acceleration of 351.6 cm/sec2 or less was useful for detecting high-grade stenosis, but there was difficulty in distinguishing unilateral from bilateral high-grade stenosis. TCD measurement of the flow acceleration allows for fairly reliable detection of high-grade stenosis and can thus serve as a useful indirect component of a carotid noninvasive battery.

Aged↗
PubMed1992

TIA and minor stroke. How to identify and treat patients at risk for recurrent cerebral ischemia.

Clinicians should take a mechanistic approach to transient ischemic attack and stroke. Distinguishing between hemorrhagic and ischemic stroke is important and is most readily accomplished with a computed tomographic brain scan. Newer diagnostic studies are now available to help evaluate patients for a cardiogenic source of embolism. Detection of a cardiogenic source of embolism or high-grade carotid stenosis identifies stroke-prone persons in whom interventional therapy is beneficial.

Anticoagulants↗
PubMed1992

Transcranial Doppler assessment of cerebral flow velocity during cognitive tasks.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the ability of transcranial Doppler ultrasonography to detect selective circulatory changes during cognitive activity. METHODS: We measured cerebral artery flow velocity in 21 normal volunteers by transcranial Doppler ultrasonography during rest followed by cerebral activation. Mean and peak systolic flow velocities of the anterior, middle, and posterior cerebral arteries were measured during the performance of a commercial video game. We also measured flow velocity of the anterior cerebral arteries in 18 subjects during a mental arithmetic task. Serial measurements of the right and left sides were made with a headband with two probes. RESULTS: We observed a global increase in the flow velocity above baseline measurements during task performance. During the video game, both middle cerebral arteries (t = 2.6, p = 0.02 for the left; t = 3.3, p = 0.004 for the right) and the left posterior cerebral artery (t = 2.2, p = 0.004) had selective increase in mean flow velocity compared with the ipsilateral anterior cerebral artery. This selective activation was most prominent in the right middle cerebral artery, which had a greater degree of activation than the right posterior cerebral artery (t = 2.8, p = 0.013). We did not observe a statistically significant difference between the right and left middle cerebral arteries, but there was a trend toward a greater activation on the right for both the mean velocity (t = 1.7, p = 0.098) and the peak velocity (t = 1.9, p = 0.079). CONCLUSIONS: Our preliminary investigation suggests that this noninvasive technique has the potential to correlate selective cerebral artery flow dynamics with cognitive activity.

Adolescent↗
PubMed1992

Rationale for antithrombotic therapy in atrial fibrillation.

Antithrombotic therapy is clearly indicated in patients with atrial fibrillation who have associated factors that put them at significant risk for thromboembolism This does not include subjects with lone atrial fibrillation who are less than 60 years of age. High-risk patients include those with valvular heart disease, recent congestive heart failure, severe left ventricular dysfunction by echocardiography, prior thromboembolism, demonstration of a cardiac thrombus by echocardiography, and thyrotoxicosis. Anticoagulant therapy appears to be the most efficacious means of preventing thromboembolism in atrial fibrillation. Potential bleeding complications with sodium warfarin mandate judicious selection of patients for long-term anticoagulant therapy. The risk of anticoagulant therapy certainly appears justified in subjects who are at high risk for thromboembolism and can be monitored with a reasonable degree of safety. Aspirin therapy is a reasonable alternative for those subjects at relatively lower risk of thromboembolism, especially subjects who are not suitable candidates for anticoagulation. The efficacy of aspirin has not been established in patients with atrial fibrillation who are greater than 75 years of age.

Aspirin↗