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Biomedical subjects

S R Levine

Publications and source records attributed to S R Levine.

At least 73 records · Page 4Linked to original sources
PubMed1995

A model to predict the histopathology of human stroke using diffusion and T2-weighted magnetic resonance imaging.

BACKGROUND AND PURPOSE: We sought to identify MRI measures that have high probability in a short acquisition time to predict, at early time points after onset of ischemia, the eventual development of cerebral infarction in clinical patients who suffer occlusion of a cerebral artery. METHODS: We developed an MR tissue signature model based on experimentally derived relationships of the apparent diffusion coefficient of water (ADCw) and T2 to ischemic brain tissue histopathology. In eight stroke patients we measured ADCw and T2 intensity using diffusion-weighted echo-planar imaging (DW-EPI). Tissue signature regions were defined, and theme maps of the ischemic focus at subacute time points after stroke onset were generated. RESULTS: Five MR signatures were identified in human stroke foci: two that may predict either cell recovery or progression to necrosis, one that may mark the transition to cell necrosis, and two that may be markers of established cell necrosis. CONCLUSIONS: An MR tissue signature model of ischemic histopathology using ADCw and T2 can now be tested for its potential to predict reversible and identify irreversible cellular damage in human ischemic brain regions.

Aged↗
PubMed1995

Vasospasm and thrombus formation as possible mechanisms of stroke related to alkaloidal cocaine.

BACKGROUND: "Crack" cocaine (alkaloidal cocaine) induces ischemic stroke. However, the mechanisms by which this occurs are not well documented in humans. We present pertinent information on three patients whose ischemic strokes involved the territory of the internal carotid artery and were associated with crack use. CASE DESCRIPTIONS: These patients were investigated clinically, radiologically, intraoperatively, and/or histopathologically at the same institution, and the diagnostic evaluations did not reveal a definite cardiac or hematologic cause of stroke. Large filling defects were noted on conventional carotid angiography in two of these patients; in the third patient, the histopathological changes were compatible with vasospasm. To our knowledge, these changes have not been previously documented in human arteries. CONCLUSIONS: We suggest that some brain infarcts among crack cocaine users may result from vasospasm of large arteries and secondary intravascular thrombosis.

Adult↗
PubMed1995

The Warfarin-Aspirin Symptomatic Intracranial Disease Study.

We conducted a retrospective, multicenter study to compare the efficacy of warfarin with aspirin for the prevention of major vascular events (ischemic stroke, myocardial infarction, or sudden death) in patients with symptomatic stenosis of a major intracranial artery. Patients with 50 to 99% stenosis of an intracranial artery (carotid; anterior, middle, or posterior cerebral; vertebral; or basilar) were identified by reviewing the results of consecutive angiograms performed at participating centers between 1985 and 1991. Only patients with TIA or stroke in the territory of the stenotic artery qualified for inclusion in the study. Patients were prescribed warfarin or aspirin according to local physician preference and were followed by chart review and personal or telephone interview. Seven centers enrolled 151 patients; 88 were treated with warfarin and 63 were treated with aspirin. Median follow-up was 14.7 months (warfarin group) and 19.3 months (aspirin group). Vascular risk factors and mean percent stenosis of the symptomatic artery were similar in the two groups, yet the rates of major vascular events were 18.1 per 100 patient-years of follow-up in the aspirin group (stroke rate, 10.4/100 patient-years; myocardial infarction or sudden death rate, 7.7/100 patient-years) compared with 8.4 per 100 patient-years of follow-up in the warfarin group (stroke rate, 3.6/100 patient-years; myocardial infarction or sudden death rate, 4.8/100 patient-years). Kaplan-Meier analysis showed a significantly higher percentage of patients free of major vascular events among patients treated with warfarin (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Digital rectal examination, serum prostate specific antigen, and prostatic ultrasound: how effective is this diagnostic triad?

Ninety-nine of 105 consecutive men who underwent transrectal prostatic ultrasound (TRUS) at Highland Park Hospital had the results correlated with digital rectal examination (DRE), serum prostate specific antigen (PSA), and biopsy results. Ninety-six cases had evaluable ultrasound studies. Thirty-two of the 99 who underwent biopsy had primary carcinoma of the prostate. Prostate volume, predicted PSA, a ratio of observed/predicted PSA, and Gleason score were examined. There was no correlation between age and prostate volume, volume and the presence of carcinoma, or PSA and Gleason score. Thirty-one point six percent of the abnormal DREs, 36.6% of the abnormal TRUSs, and 40.6% of the elevated PSAs occurred in men with prostatic carcinoma (PCa). If PSA was normal (less than or equal to 4.0 ng/ml) and either DRE or TRUS was abnormal, then the risk of carcinoma was 2.9%. If PSA was elevated, regardless of the other two tests, the risk of finding PCa was at least 38%. If all three tests were abnormal, the risk of carcinoma was 38% in our series and 68% in a meta-analysis. Many men with PSA values between 4 and 10 ng/ml have benign biopsies. However, close future follow-up with consideration of repeat biopsy should be strongly considered.

Aged↗
PubMed1994

Cerebral blood flow in migraine accompaniments and vertebrobasilar ischemia.

BACKGROUND AND PURPOSE: Transient neurological symptoms of brain stem or occipital lobe origin may be caused by transient ischemic attack in the vertebrobasilar territory (VB-TIA) or late-onset (or late-life) migraine accompaniment (LOMA). It is often clinically difficult to distinguish between VB-TIA and LOMA. METHODS: Cerebral blood flow of 23 patients with VB-TIA, 24 with LOMA, and 28 age-matched control subjects was measured using the 133Xe inhalation regional cerebral blood flow (rCBF) technique. RESULTS: After adjusting for differences in baseline variables such as blood pressure, hematocrit, and PCO2, patients with VB-TIA had (1) lower mean rCBF than control subjects (P < .003) as measured by the initial slope index method; (2) more frequent anterior rCBF asymmetries than control subjects and patients with LOMA (P < .03 for both comparisons); and (3) higher mean interhemispheric rCBF differences compared with patients with LOMA (P = .08) and control subjects (P < .02). CONCLUSIONS: Regional CBF patterns in patients with VB-TIA and LOMA differ, with lower rCBF and more asymmetry of the anterior blood flows in patients with VB-TIA, probably reflecting the effects of stroke risk factors on the cerebral circulation. Patients with LOMA have rCBF patterns more closely resembling those of age-matched healthy subjects. rCBF measurements may assist in the clinical diagnosis of VB-TIA and late-onset migrainous events.

Aged↗
PubMed1994

Large cerebral vessel occlusive disease in systemic lupus erythematosus.

We systematically investigated clinical, laboratory, radiologic, and pathologic features, including treatment and prognosis, of stroke syndromes in 30 patients, six from our institution and 24 from the literature, with systemic lupus erythematosus (SLE) and symptomatic large cerebral vessel occlusive disease, documented by angiography or autopsy. The average age at stroke onset was 35 years, and the diagnosis of SLE was made on average 4.4 years prior to that. At least 86% had active SLE at the time of their stroke. Headache was common at onset. We found major intracranial or extracranial vessel occlusive process by (1) thrombus, (2) dissection, (3) fibromuscular dysplasia or vasculitis, and (4) atherosclerosis. The presumed mechanisms were coagulopathy, cardiogenic embolism, large cerebral vessel vasculitis or occlusive vasculopathy, cervical arterial dissection, and premature atherosclerosis. The short-term death rate was 40% and the recurrent stroke rate was 13%. We conclude that symptomatic large cerebral vessel occlusive disease in SLE generally occurs several years after the diagnosis of SLE, usually during the active phase of the disease, is related to heterogeneous mechanisms, and carries a relatively poor short-term outcome.

Adult↗
PubMed1993

Altered brain energy metabolism in demented patients with multiple subcortical ischemic lesions. Working hypotheses.

We report the results of brain metabolic studies (using magnetic resonance spectroscopy) in three groups of individuals: (1) demented patients with multiple subcortical ischemic lesions (n = 18); (2) nondemented, age-matched controls (n = 21); and (3) demented patients with neurodegenerative disease, probably of the Alzheimer type (n = 19). Patients with dementia with subcortical vascular lesions, as demonstrated by appropriate imaging studies, had an increase of phosphate energy charge in areas of the cerebral cortex (especially prominent in the frontal regions) superficial to and excluded from the subcortical lesions. We hypothesize that this increased energy charge might be caused by reduced metabolic activity of disconnected brain tissue or by astrocytic hypertrophy and hyperplasia that accompanies subtle ischemic, cortical alterations.

Adenosine Triphosphate↗
PubMed1993

Factors that predict antiphospholipid immunoreactivity in young people with transient focal neurological events.

OBJECTIVE: To determine if clinical or radiological features in young people with transient focal neurological events may be used to predict the presence of antiphospholipid antibodies (aPL). DESIGN: A combined retrospective and prospective study of young people with transient focal neurological events. Likelihood ratios and confidence intervals were calculated for the proportions; logistic regression analysis was performed to determine features predictive of aPL immunoreactivity. SETTING: A referral hospital and adjacent outpatient clinic. PATIENTS: Sixty-eight patients with one or more transient focal neurological events were screened for aPL. Forty-seven patients were obtained retrospectively from medical record review of every outpatient personally seen by two of us (G.E.T. and S.R.L.) during a 4.5-year period. Twenty-one patients were prospectively added prior to retrospective analysis. Patients older than 50 years or those with multiple sclerosis or epilepsy were excluded. Five patients fulfilling study criteria were excluded because aPL assay results were unavailable. MAIN OUTCOME MEASURES: Transient neurological symptoms, stroke risk factors, occurrence of cerebral or ocular infarct or death, headache history, and serological and radiological studies were systematically obtained. RESULTS: There were 29 aPL-positive patients compared with 39 aPL-negative ones. Features that distinguished the aPL-positive group included more common monocular visual symptoms (38% vs 15%, P = .03), hemisensory symptoms (76% vs 41%, P = .004), and systemic lupus erythematosus (14% vs 0%, P = .03) and less common binocular visual symptoms (28% vs 51%, P = .05), accompanying headache (66% vs 87%, P = .03), and personal (48% vs 74%, P = .03) and family (29% vs 61%, P = .01) history of migraine. No differences were noted between the groups for age, gender, stroke risk factor profile, and radiological features. In a logistic regression analysis, the estimated odds ratio for aPL positivity in patients with monocular visual disturbance, hemisensory symptoms, and no family history of migraine were 5.3, 7.5, and 3.0, respectively, when controlling for the other variables. CONCLUSIONS: Several clinical features of transient focal neurological events in aPL-positive patients distinguish these individuals from their aPL-negative cohort. Amaurosis fugax, unilateral paresthesias, and no family history of migraine may predict aPL positivity in young persons with transient focal neurological deficits.

Adolescent↗
PubMed1993

Cerebellar infarction. Clinical and anatomic observations in 66 cases.

BACKGROUND AND PURPOSE: Cerebellar infarction displays different clinical features, depending on the vascular territory involved. We studied patients with infarcts in the territories of the posterior inferior cerebellar artery or the superior cerebellar artery to compare their clinical presentation, course, and prognosis. METHODS: We retrospectively analyzed the clinical features, laboratory data, and imaging studies of 66 patients with cerebellar infarction collected consecutively at five institutions. All the cerebellar infarcts were documented on computed tomographic scan or magnetic resonance imaging. RESULTS: Two distinct profiles emerged, depending on the vascular territory involved. In 36 patients with posterior inferior cerebellar artery territory infarcts, a triad of vertigo, headache, and gait imbalance predominated at stroke onset. Computed tomography showed severe cerebellar mass effect in 11 cases (30%), with associated hydrocephalus in seven. In these seven patients (19%), postinfarct swelling led to brain stem compression that resulted in four deaths. In 30 patients with superior cerebellar artery infarcts, gait disturbance predominated at onset; vertigo and headache were significantly less common. The clinical course was usually benign. Computed tomography showed marked cerebellar mass effect, hydrocephalus, and brain stem compression in only two instances (7%). Presumed cerebral embolism was the predominant stroke mechanism in patients with superior cerebellar artery distribution infarcts, whereas in those with posterior inferior cerebellar artery distribution infarcts, the stroke mechanism was equally divided between cardiogenic embolism and posterior circulation arterial disease. CONCLUSIONS: Cerebellar infarcts in the posterior inferior cerebellar artery and superior cerebellar artery distribution have distinct differences in clinical presentation, course, and prognosis. These differences should help in the selection of appropriate monitoring and treatment strategies.

Adolescent↗
PubMed1993

Factors associated with early presentation of acute stroke.

BACKGROUND AND PURPOSE: Patients with stroke symptoms commonly delay many hours before seeking medical attention. We sought to explore the factors associated with early presentation of stroke patients to physicians. METHODS: We prospectively studied 100 consecutive acute stroke patients presenting to three large, urban medical centers. Using a standardized, structured interview and chart review, we assessed patient education about stroke, risk factors, clinical features of the stroke, source of stroke recognition, and timing of presentation. We did not study the distance from the site of stroke onset to the site of physician contact. RESULTS: Stroke onset time was known in 96 of the patients. Mean patient age was 71.3 years, 79% had at least one stroke risk factor, 26% had prior transient ischemic attack, 19% had prior stroke, 74% had some high school education, and 86% had regular physicians. Only 8% had been previously educated about stroke symptoms. Eighty one percent of strokes were ischemic. The mean time to physician contact was 13.4 +/- 2.3 hours (median, 4.0 hours) and to neurologist contact was 21.2 +/- 2.9 hours. A skewed distribution of presentation times accounts for the mean-median differences. A small number of patients presenting very late could have an effect on the correlations between presentation time and the variables studied. Early presentation time was associated with increased age, the sudden onset of a stable deficit, and recognition that the symptoms signified stroke. Only the sudden onset of a stable deficit correlated independently with early presentation time (P = .0048). There was no correlation between presentation time and prior transient ischemic attack or stroke, headache, vomiting, loss of consciousness or seizures at onset, or stroke subtype, but a type II error could not be excluded. CONCLUSIONS: Despite their education level, regular health care, and risk factors, especially prior stroke and transient ischemic attack, these patients were not knowledgeable about stroke and delayed many hours before contacting physicians. The course of symptoms and recognition that they signified stroke were associated with earlier presentation. Patient education focused on groups at risk may hasten the presentation and treatment of acute stroke.

Acute Disease↗
PubMed1993

Possible association of ischemic stroke with phentermine.

BACKGROUND AND PURPOSE: Some commonly used anorexiants, including methamphetamine and phenylpropanolamine, have been associated with stroke. Because phentermine is an anorexiant with a chemical structure similar to that of amphetamines, similar side effects might be expected. CASE DESCRIPTIONS: Two patients using phentermine (one was also using phendimetrazine) developed ischemic cerebrovascular disease. One suffered a cerebral infarct with angiographic evidence of vasculopathy involving multiple vascular beds. The other patient developed headache and a hemisensory disturbance of 7 days' duration. CONCLUSIONS: Phentermine, and possibly phendimetrazine, should be considered an anorexiant and sympathomimetic drug that can be associated with ischemic cerebrovascular disease.

Adult↗
PubMed1993

Intramedullary spinal sarcoidosis: clinical and magnetic resonance imaging characteristics.

We present a retrospective series of the clinical and MRI findings in 16 patients with intramedullary spinal sarcoidosis (ISS), including 12 patients studied with gadolinium-DTPA. The spectrum of MRI findings includes leptomeningeal enhancement, fusiform spinal cord enlargement, focal or diffuse intramedullary disease, and spinal cord atrophy. We present a classification of ISS correlating the clinical progression and the temporal sequence of MRI abnormalities. Improvement occurred in five of 12 patients (42%) treated with immunosuppressive therapy.

Adult↗
PubMed1993

Acute elevation and recovery of intracellular [Mg2+] following human focal cerebral ischemia.

We used 31P magnetic resonance spectroscopy (MRS) to investigate changes in brain intracellular [Mg2+] following human focal cerebral ischemia. Mean brain pMg (where pMg = -log[Mg2+]) was significantly lower in the ischemic focus of all stroke patients (pMg = 3.34 +/- 0.28, n = 45, p < 0.01) when compared with normal controls (pMg = 3.50 +/- 0.08, n = 25). Ischemic brain pMg was also significantly reduced when the pH of the stroke region was acidotic (pH < 6.90, pMg = 3.07 +/- 0.44, n = 11, p < 0.01) and when the phosphocreatine index (PCrI = PCr/[PCr+Pi (inorganic phosphate)]) was reduced (PCrI < 0.47, pMg = 3.12 +/- 0.42, n = 13, p < 0.01). Mean brain pMg was significantly reduced at days 0 to 1 (acute) poststroke (pMg = 3.32 +/- 0.28, n = 26, p < 0.01) and at days 2 to 3 (subacute) poststroke (pMg = 3.38 +/- 0.28, n = 21, p = 0.03). There was also a significant (p < 0.01) correlation between decreased pMg and increased relative signal intensity of Pi (normalized by total phosphate signal, Pi/TP) for all stroke groups studied. During the temporal evolution of stroke, pH returned to normal levels by days 2 to 3, and pMg returned to normal by days 4 to 10 (subacute). PCrI and Pi/TP returned toward normal levels after 10 days (chronic), at a time when ischemic brain pH had become significantly alkalotic (pH = 7.10 +/- 0.24, n = 15, p < 0.01). Elevation of ischemic brain [Mg2+] is temporally linked to the acidotic phase of human stroke as well as the breakdown of energy metabolism. These acute changes in [Mg2+] may contribute to, or be a marker for, cellular injury.

Adenosine Triphosphate↗
PubMed1993

Stroke.

Illicit drugs, appetite suppressants, decongestants, and anabolic steroids may cause stroke. Drug abuse is a common cause of stroke in young patients. Mechanisms are varied, but it is particularly important to seek out infective endocarditis and most importantly, cerebral aneurysms, vascular malformations, and cardiac disorders in cocaine abusers. Drug-induced vasoconstriction, hypertension, or vasculitis probably contributes significantly to most patients' strokes. Tobacco smoking and heavy chronic alcohol consumption are independent risk factors for stroke; moderate drinking seems to protect from stroke in white patients. Oral contraceptives may increase the risk of stroke in female patients over 35 years of age who also have other risk factors.

Adult↗