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Biomedical subjects

R J Wityk

Publications and source records attributed to R J Wityk.

At least 37 records · Page 2Linked to original sources
PubMed1999

Distribution and correlates of elevated total homocyst(e)ine: the Stroke Prevention in Young Women Study.

PURPOSE: To determine the distribution and correlates of elevated total homocyst(e)ine (tHcy) concentration in a population of premenopausal black and white women. METHODS: Data from the Stroke Prevention in Young Women Study (N = 304), a population-based study of risk factors for stroke in women aged 15-44 years of age, were used to determine the distribution and correlates of elevated tHcy in black (N = 103) and white women (N = 201). RESULTS: The mean tHcy level for the population was 6.58 micromol/L (range 2.89-26.5 micromol/L). Mean tHcy levels increased with age, cholesterol level, alcohol intake, and number of cigarettes smoked (all: p < 0.05). There were no race differences (mean tHcy 6.72 micromol/L among blacks and 6.51 micromol/L among whites; p = 0.4346). Regular use of multivitamins and increasing education was associated with significant reductions in tHcy concentration. Approximately 13% of the sample had elevated tHcy levels, defined as a tHcy concentration > or = 10.0 micromol/L. Multivariate-adjusted correlates of elevated tHcy included education > 12 vs. < or = 12 (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.2-0.8); smoking > or = 20 cigarettes/day vs. nonsmokers (OR = 2.8, 95% CI = 1.1-7.3); and the regular use of multivitamins (OR = 0.4, 95% CI = 0.2-0.9). CONCLUSIONS: These results suggest that a substantial proportion of healthy young premenopausal women have tHcy levels that increase their risk for vascular disease. A number of potentially modifiable behavioral and environmental factors appear to be significantly related to elevated tHcy levels in young women.

Adolescent↗
PubMed1999

Elevated tissue plasminogen activator antigen and stroke risk: The Stroke Prevention In Young Women Study.

BACKGROUND AND PURPOSE: Abnormalities in endogenous fibrinolysis are associated with an increased risk for stroke in men and older adults. We tested the hypothesis that elevated plasma tissue plasminogen activator (tPA) antigen, a marker for impaired endogenous fibrinolysis, is an independent risk factor for stroke in young women. METHODS: Subjects were 59 nondiabetic females ages 15 to 44 years with cerebral infarction from the Baltimore-Washington area and 97 control subjects frequency-matched for age who were recruited by random-digit dialing from the same geographic area. A history of cerebrovascular disease risk factors was obtained by face-to-face interview. Plasma tPA antigen was measured by enzyme-linked immunosorbent assay. RESULTS: Mean plasma tPA antigen levels were significantly higher in stroke patients than control subjects (4. 80+/-4.18 versus 3.23+/-3.67 ng/mL; P=0.015). After adjustment for age, hypertension, cigarette smoking, body mass index, and ischemic heart disease, there was a dose-response association between tPA antigen and stroke with a 3.9-fold odds ratio of stroke (95% CI, 1.2 to 12.4; P=0.03) for the upper quartile (>4.9 ng/mL) of tPA antigen compared with the lowest quartile. The dose-response relationship between tPA antigen and stroke was equally present in white and nonwhite women, and further adjustment for total and HDL cholesterol levels only modestly attenuated this association. CONCLUSIONS: This population-based case-control study shows that elevated plasma tPA antigen level is independently associated with an increased risk for ischemic stroke in nondiabetic females 15 to 44 years of age. These findings support the hypothesis that impaired endogenous fibrinolysis is an important risk factor for stroke in young women.

Adolescent↗
PubMed1999

Homocyst(e)ine and risk of cerebral infarction in a biracial population : the stroke prevention in young women study.

BACKGROUND AND PURPOSE: Genetic enzyme variation and vitamin intake are important determinants of blood homocyst(e)ine levels. The prevalence of common genetic polymorphisms influencing homocyst(e)ine levels varies by race, and vitamin intake varies by socioeconomic status. Therefore, we examined the effect of vitamin intake, race, and socioeconomic status on the association of homocyst(e)ine with stroke risk. METHODS: All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. One hundred sixty-seven cases of first ischemic stroke among women aged 15 to 44 years were compared with 328 controls identified by random-digit dialing from the same region. Risk factor data were collected by standardized interview and nonfasting phlebotomy. Plasma homocyst(e)ine was measured by high-performance liquid chromatography and electrochemical detection. RESULTS: Blacks and whites did not differ in median homocyst(e)ine levels, nor did race modify the association between homocyst(e)ine and stroke. After adjustment for cigarettes per day, poverty status, and regular vitamin use, a plasma homocyst(e)ine level of >/=7.3 micromol/L was associated with an odds ratio for stroke of 1.6 (95% CI, 1.1 to 2.5). CONCLUSIONS: The association between elevated homocyst(e)ine and stroke was independent not only of traditional vascular risk factors but also of vitamin use and poverty status. The degree of homocyst(e)ine elevation associated with an increased stroke risk in young women is lower than that previously reported for middle-aged men and the elderly and was highly prevalent, being present in one third of the control group.

Adolescent↗
PubMed1998

Proximal extracranial vertebral artery disease in the New England Medical Center Posterior Circulation Registry.

OBJECTIVE: To describe the clinical features of patients with occlusive disease of the proximal (V1) segment of the vertebral artery. DESIGN AND PATIENTS: Patients with either occlusion or high-grade stenosis involving the V1 segment were chosen for study from the New England Medical Center Posterior Circulation Registry. The registry is a consecutive series of patients with signs and symptoms of posterior circulation ischemia seen at the New England Medical Center, Boston, Mass, during a 10-year period. Clinical features, radiographic findings, and patient outcome were reviewed. RESULTS: Of the 407 patients in the registry, 80 (20%) had V1 segment lesions. Patients could be classified into 5 groups: (1) V1 disease and coexistent severe intracranial occlusive disease of the posterior circulation (n=22); (2) V1 disease with evidence of artery-to-artery embolism (n=19); (3) suspected V1 disease with artery-to-artery embolism, but with other potential causes of stroke or less certain vascular diagnosis (n=20); (4) V1 disease associated with hemodynamic transient ischemic attacks (n=13); and (5) proximal vertebral arterial dissection (n=6). Hypertension, cigarette smoking, and coronary artery disease were common risk factors. Clinical features, location of infarct, and outcome differed between groups and reflected the presumed mechanisms of stroke. CONCLUSIONS: Occlusive disease involving the V1 segment of the vertebral artery is common in patients with posterior circulation ischemia, but is often associated with other potential mechanisms of stroke. However, in a series of patients seen at a tertiary referral center, occlusive disease of the V1 segment was the primary mechanism of ischemia in 9% of patients.

Academic Medical Centers↗
PubMed1998

Transient migraine-like symptoms with internal carotid artery dissection.

We report three patients with angiographically confirmed internal carotid artery (ICA) dissection who presented with transient symptoms resembling migraine with aura. Marching impairments from one modality to another preceded recognition of the diagnosis of dissection and were not associated with clinical or radiologic evidence of cerebral infarction. We review the clinical patterns in which ICA dissection may be identified in the setting of migrainous symptoms, given the different therapeutic approaches to migraine and dissection and the non-invasive means to diagnose dissection with magnetic resonance imaging (MRI). We offer mechanisms for recurrent neurologic symptoms in patients with ICA dissection.

Adult↗
PubMed1998

Recent advances in stroke therapy.

Advances in stroke therapy have followed diverse paths over the past 2 years. Recent clinical trials have investigated the use of thrombolytic agents, anticoagulants, antiplatelet drugs and neuroprotective agents in acute stroke patients. The positive results of the National Institutes of Neurologic Disease and Stroke tissue plasminogen activator trial have increased interest in the field of acute stroke therapy and initiated significant changes in the management of stroke patients in the medical system. A new antiplatelet drug and a number of trials involving HMG Co-A reductase inhibitors are important advances in the secondary prevention of stroke.

Acute Disease↗
PubMed1998

Nonconvulsive status epilepticus in the critically ill elderly.

PURPOSE: To describe the electrographic and clinical features of nonconvulsive status epilepticus (NCSE) in the critically ill elderly and to identify potential predictors of outcome. METHODS: We prospectively identified 25 episodes of altered mentation and NCSE in 24 critically ill elderly patients associated with generalized, focal, or bihemispheric epileptiform EEG patterns. Patients with anoxic encephalopathy were excluded. RESULTS: Of 25 hospitalizations, 13 (52%) resulted in death, and 12 (48%) patients survived to discharge. Death was associated with the number of acute, life-threatening medical problems on presentation (survivors, 1.8; fatalities, 2.8; p = 0.013) and with generalized EEG pattern (p = 0.017). Higher doses or greater number of antiepileptic drugs (AEDs) did not improve outcome. Treatment with intravenous benzodiazepines was associated with increased risk of death (p = 0.033). Ten patients with advance directives were managed outside the intensive care unit (ICU). Mean hospitalization was 39 days in the ICU group and 22 for those with advance directives (p = 0.017). CONCLUSIONS: Severity of illness correlates with mortality in critically ill elderly patients with NCSE. Treatment with intravenous benzodiazepines may increase their risk of death. Aggressive ICU management may prolong hospitalization at considerable cost, without improving outcome. It is unclear whether NCSE affects outcome in the critically ill elderly or is merely a marker for severity of disease in predisposed patients. The benefits of aggressive therapy are unclear. Carefully controlled, prospective trials will be necessary to determine the best therapies for NCSE in the critically ill elderly and the appropriate role of the ICU in their management.

Aged↗
PubMed1998

Platelet glycoprotein receptor IIIa polymorphism P1A2 and ischemic stroke risk: the Stroke Prevention in Young Women Study.

BACKGROUND AND PURPOSE: Platelet glycoprotein IIb/IIa (GpIIb-IIIa), a membrane receptor for fibrinogen and von Willebrand factor, has been implicated in the pathogenesis of acute coronary syndromes but has not been previously investigated in relation to stroke in young adults. METHODS: We used a population-based case-control design to examine the association of the GpIIIa polymorphism P1A2 with stroke in young women. Subjects were 65 cerebral infarction cases (18 patients with and 47 without an identified probable etiology) 15 to 44 years of age from the Baltimore-Washington region and 122 controls frequency matched by age from the same geographic area. A face-to-face interview for vascular disease risk factors and a blood sample for the P1A2 allele and serum cholesterol were obtained from each participant. Logistic regression was used to estimate the odds ratio for one or more P1A2 alleles after adjustment for other risk factors. RESULTS: Among cases and controls, the prevalence rates of one or more P1A2 alleles were 21% and 22% among blacks and 36% and 28% among whites, respectively. This genotype was significantly associated with hypertension only in black control subjects but otherwise not with any of the established vascular risk factors. The adjusted odds ratio for cerebral infarction of one or more P1A2 alleles was 1.1 (confidence interval [CI], 0.6 to 2.3) overall, 0.5 (CI, 0.1 to 7.1) among blacks, and 1.4 (CI, 0.5 to 3.7) among whites. For the cases with an identified probable etiology, the corresponding odds ratios were 3.0 (CI, 0.9 to 10.4) overall, 0.7 (CI, 0.1 to 7.1) among blacks, and 12.8 (CI, 1.2 to 135.0) among whites. CONCLUSIONS: No association was found between the P1A2 polymorphism of GpIIIa and young women with stroke. However, subgroup analyses showed that the P1A2 polymorphism of GpIIIa appeared to be associated with stroke risk among white women, particularly those with a clinically identified probable etiology for their stroke. Further work with an emphasis on stroke subtypes and with multiracial populations is warranted.

Adolescent↗
PubMed1998

Cerebral infarction in young adults: the Baltimore-Washington Cooperative Young Stroke Study.

BACKGROUND: Few reports on stroke in young adults have included cases from all community and referral hospitals in a defined geographic region. METHODS: At 46 hospitals in Baltimore City, 5 central Maryland counties, and Washington, DC, the chart of every patient 15 to 44 years of age with a primary or secondary diagnosis of possible cerebral arterial infarction during 1988 and 1991 was abstracted. Probable and possible etiologies were assigned following written guidelines. RESULTS: Of 428 first strokes, 212 (49.5%) were assigned at least one probable cause, 80 (18.7%) had no probable cause but at least one possible cause, and 136 (31.8%) had no identified probable or possible cause. Of the 212 with at least one probable cause, the distribution of etiologies was cardiac embolism (31.1%), hematologic and other (19.8%), small vessel (lacunar) disease (19.8%), nonatherosclerotic vasculopathy (11.3%), illicit drug use (9.4%), oral contraceptive use (5.2%), large artery atherosclerotic disease (3.8%), and migraine (1.4%). There were an additional 69 recurrent stroke patients. CONCLUSIONS: In this hospital-based registry within a region characterized by racial/ethnic diversity, cardiac embolism, hematologic and other causes, and lacunar stroke were the most common etiologies of cerebral infarction in young adults. Nearly a third of both first and recurrent strokes had no identified cause.

Adolescent↗
PubMed1998

Illicit drug-associated ischemic stroke in the Baltimore-Washington Young Stroke Study.

BACKGROUND: Limited information exists on the frequency, trends in occurrence, risk factors, mechanisms, and outcome of ischemic stroke associated with illicit drug use among young adults in a geographically defined population. METHODS: We reviewed ischemic stroke in young adults (aged 15 to 44 years) in 46 regional hospitals for 1988 and 1991. We examined stroke mechanisms and outcome in patients with recent drug use. RESULTS: Recent illicit drug use was noted in 51/422 (12.1%) stroke patients. Patients with drug use were more likely than other stroke patients to be black (p=0.01), aged 25 to 39 years (p=0.004), and smokers (p=0.006), and were less likely to have hypertension (p=0.004) or diabetes mellitus (p=0.004). Drug use was the probable cause of stroke in 20 (4.7%) patients. Among 31 (7.3%) patients with drug use as a possible stroke mechanism, more likely diagnoses included cardioembolic stroke in 18, hematologic/collagen vascular in 6, nonatherosclerotic vasculopathy in 5, and atherosclerosis in 3. There was no difference in outcome between drug-associated and non-drug associated stroke. CONCLUSIONS: Recent illicit drug use occurs in 12.1% of young adult stroke patients. Drug-associated young adult stroke seems to relate to vascular mechanisms other than those related to hypertension or diabetes. Case-control studies are needed.

Adolescent↗
PubMed1998

Thermolabile methylenetetrahydrofolate reductase polymorphism (C677T) and total homocysteine concentration among African-American and white women.

A polymorphism associated with a thermolabile variant (C677T) of the enzyme methylenetetrahydrofolate reductase has been associated with both elevated total homocysteine (tHcy) levels and risk for cardiovascular disease. Data from the Stroke Prevention in Young Women Study were used to determine the prevalence of the C677T genotype and to assess whether environmental factors modified the association between genotype and tHcy concentration. The C677T genotype prevalence was 80% -/-, 20% +/-, and 0% +/+ among 46 African-American women; and 39% -/-, 53% +/-, and 8% +/+ among 77 white women (P < 0.01). There was a trend toward higher tHcy levels in African-American women with the +/- genotype when compared with the -/- genotype (6.9 mumol/L vs 5.3 mumol/L respectively, p = 0.10); no association was found among the white women (6.0 mumol/L, -/-; 4.5 mumol/L, +/-; and 6.2 mumol/L, +/+; p = 0.67). Among African American women, those who smoked and were +/- genotype had the highest tHcy levels (8.0 mumol/L); while among white women, those who smoked and were -/- had the highest tHcy levels (8.1 mumol/L). Despite being hampered by a limited sample size, the thermolabile allele is significantly less common among African-American than white women. The association between genotype and tHcy concentration is influenced by smoking and multivitamin use.

Adolescent↗
PubMed1996

Pregnancy and the risk of stroke.

BACKGROUND: It is widely believed that pregnancy increases the risk of stroke, but there are few data available to quantify that risk. METHODS: We identified all female patients 15 through 44 years of age in central Maryland and Washington, D.C., who were discharged from any of 46 hospitals in the study area in 1988 or 1991. Two neurologists reviewed each case, using data from the women's medical records. We determined whether the women had been pregnant at the time of the stroke or up to six weeks before it occurred. For purposes of this analysis, the six-week period after pregnancy could begin with an induced or spontaneous abortion or with the delivery of a live or stillborn child. RESULTS: Seventeen cerebral infarctions and 14 intracerebral hemorrhages occurred in women who were or had recently been pregnant (pregnancy-related strokes), and there were 175 cerebral infarctions and 48 intracerebral hemorrhages that were not related to pregnancy. For cerebral infarction, the relative risk during pregnancy, adjusted age and race, was 0.7 (95 percent confidence interval, 0.3 to 1.6), but it increased to 8.7 for the postpartum period (after a live birth or stillbirth) (95 percent confidence interval, 4.6 to 16.7). For intracerebral hemorrhage, the adjusted relative risk was 2.5 during pregnancy (95 percent confidence interval, 1.0 to 6.4) but 28.3 for the postpartum period (95 percent confidence interval, 13.0 to 61.4). Overall, for either type of stroke during or within six weeks after pregnancy, the adjusted relative risk was 2.4 (95 percent confidence interval, 1.6 to 3.6), and the attributable, or excess, risk was 8.1 strokes per 100,000 pregnancies (95 percent confidence interval, 6.4 to 9.7). CONCLUSIONS: The risks of both cerebral infarction and intracerebral hemorrhage are increased in the six weeks after delivery but not during pregnancy itself.

Cerebral Hemorrhage↗
PubMed1996

Dural arteriovenous fistula of the spinal cord: an uncommon cause of myelopathy.

Dural arteriovenous fistula is an uncommon cause of myelopathy. The nidus of the malformation is on or within the dura and results in a mass of serpentine vessels on the dorsal surface of the spinal cord, usually at low thoracic or lumbar levels. Onset is usually between ages 40 and 70 years. Male to female ratio is 4:1. Symptoms include pain, progressive proximal weakness of lower limbs, saddle area numbness, claudication, and difficulty with urination. Course may be fluctuating or slowly progressive. Signs include upper and lower motor neuron abnormalities and nondermatomal sensory loss. Spinal bruit is rare. Magnetic resonance imaging may show an enlarged cord or abnormalities on its dorsal surface. Myelography (patient prone and supine) is the procedure of choice. Motor neuron disease, disc disease, spinal cord tumor, and multiple sclerosis are differential considerations. Untreated patients have a poor prognosis. Excision of the nidus, ligation of the draining vein, and endovascular embolization may be helpful even in patients with severe deficits.

Adult↗
PubMed1996

Race and sex differences in the distribution of cerebral atherosclerosis.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the influence of race, sex, and other risk factors on the location of atherosclerotic occlusive lesions in cerebral vessels. Previous angiographic studies of patients with stroke or transient ischemic attack (TIA) suggest that extracranial atherosclerosis is more common in whites and intracranial disease is more common in blacks. Noninvasive techniques such as duplex ultrasound, transcranial Doppler (TCD), and magnetic resonance angiography (MRA) allow vascular assessment of a more representative proportion of patients than does conventional angiography alone. METHODS: Consecutive patients evaluated at a community hospital for stroke or TIA over a 2-year period were reviewed. Lesions were defined as a 50% or greater atherosclerotic stenosis by angiography, duplex ultrasound, or TCD, or a moderate stenosis by MRA. RESULTS: Whites were more likely than blacks to have extracranial carotid artery lesions (33% versus 15%, P = .001), but the proportion of patients with intracranial lesions was similar (24% versus 22%). Men were more likely to have intracranial lesions than women (29% versus 14%, P = .03). When multivariate logistic regression analysis was used, white race was the only predictor for extracranial carotid artery lesions, and male sex was the only predictor for intracranial lesions. The cause of stroke/TIA was extracranial carotid artery disease in 8% and intracranial disease in 8% of all patients in the study. CONCLUSIONS: The distribution of cerebral atherosclerosis is influenced by race and sex but not by other vascular risk factors. In our patient population, intracranial disease is as common a cause of cerebral ischemia as extracranial carotid disease.

Aged↗
PubMed1994

Ischemic stroke: today and tomorrow.

OBJECTIVE: To review selected aspects of the current treatment of acute ischemic stroke and provide an overview of basic neuroscience research in cerebral ischemia that may be applicable to future therapies. DATA SOURCES: Selected recent references dealing with current therapy of acute stroke and basic neuroscience developments in cerebrovascular disease from the past several years. STUDY SELECTION/DATA EXTRACTION: Whenever possible, recommendations concerning treatment were based on results of clinical trials; when such data were lacking, the authors present possible treatment approaches. DATA SYNTHESIS: Acute stroke is a heterogeneous process involving different etiologic mechanisms. Different types of stroke, however, may produce a similar cascade of physiologic and biochemical events leading to tissue damage. Calcium flux, glutamate excitotoxicity, platelet and leukocyte activation, free radical formation, and nitric oxide metabolism may be crucial focal points of future stroke therapy. CONCLUSIONS: Recent clinical trials have given scientific basis for some of our treatment approaches to ischemic stroke. Future treatments for stroke will likely focus on factors which modulate biochemical events occurring as a final common pathway to all forms of cerebral ischemia.

Acute Disease↗
PubMed1994

Serial assessment of acute stroke using the NIH Stroke Scale.

BACKGROUND AND PURPOSE: The National Institutes of Health (NIH) Stroke Scale has been used in clinical trials to assess neurological outcome after investigational therapy for acute stroke. We used the NIH Stroke Scale to study the degree and time course of recovery in patients with acute stroke who were treated with conventional therapy. METHODS: We serially assessed 50 patients with ischemic stroke who presented within 24 hours of onset of symptoms. Patients were grouped by stroke subtype. Major neurological improvement was defined as a decrease in the stroke score by 4 points or more. RESULTS: The mean NIH stroke score for all patients improved significantly by 7 to 10 days and at last follow-up (average, 44 days). Major neurological improvement was seen in 5 of 41 patients (12%; 95% confidence interval [CI], 2% to 22%) by 24 hours, 11 of 40 patients (28%; 95% CI, 14% to 41%) by 48 hours, and 19 of 37 patients (51%; 95% CI, 35% to 67%) by follow-up. The subgroup of patients with middle cerebral artery territory embolism showed a similar pattern of improvement; in contrast, patients with lacunar infarcts did not show significant change in scores during the study period. The score on admission did not correlate with the degree of subsequent improvement or deterioration. CONCLUSIONS: A significant percentage of patients with acute ischemic stroke treated with conventional therapy show early improvement as assessed by the NIH Stroke Scale. The degree and time course of recovery may be influenced by stroke type.

Acute Disease↗
PubMed1992

Hypertensive intracerebral hemorrhage. Epidemiology and clinical pathology.

Hypertension is the major risk factor for intracerebral hemorrhage (ICH) and is present in about 50% of patients with ICH. Common clinical findings are focal neurologic deficits at onset, gradually progressive deterioration, and the presence of headache, vomiting, and depressed level of consciousness. The clinical syndromes of ICH at common locations are reviewed. CT scanning has dramatically changed our thinking about ICH and allowed better correlation of neurologic findings with lesions at various sites.

Brain↗