Robert A. Parker

A Functional MRI Study of Subjects Recovered From Hemiparetic Stroke

BACKGROUND AND PURPOSE Stroke recovery mechanisms remain incompletely understood, particularly for subjects with cortical stroke, in whom limited data are available. We used functional magnetic resonance imaging to compare brain activations in normal controls and subjects who recovered from hemiparetic stroke. METHODS Functional magnetic resonance imaging was performed in ten stroke subjects with good recovery, five with deep, and five with cortical infarcts. Brain activation was achieved by index finger-tapping. Statistical parametric activation maps were obtained using a t test and a threshold of P < .001. In five bilateral motor regions, the volume of activated brain for each stroke subject was compared with the distribution of activation volumes among nine controls. RESULTS Control subjects activated several motor regions. During recovered hand finger-tapping, stroke subjects activated the same regions as controls, often in a larger brain volume. In the unaffected hemisphere, sensorimotor cortex activation was increased in six of nine stroke subjects compared with controls. Cerebellar hemisphere contralateral and premotor cortex ipsilateral to this region, as well as supplementary motor areas, also had increased activation. In the stroke hemisphere, activation exceeding controls was uncommon, except that three of five cortical strokes showed peri-infarct activation foci. During unaffected hand finger-tapping, increased activation by stroke subjects compared with controls was uncommon; however, decreased activation was seen in unaffected sensorimotor cortex, suggesting that this regions responsiveness increased to the ipsilateral hand and decreased to contralateral hand movements. Use of a different threshold for defining activation (P < .01) did not change the overall findings (kappa = .75). CONCLUSIONS Recovered finger-tapping by stroke subjects activated the same motor regions as controls but to a larger extent, particularly in the unaffected hemisphere. Increased reliance on these motor areas may represent an important component of motor recovery. Functional magnetic resonance imaging studies of subjects who recovered from stroke provide evidence for several processes that may be related to restoration of neurologic function.

The ischemic penumbra Operationally defined by diffusion and perfusion MRI

BACKGROUND Identifying tissue at risk for infarction is important in deciding which patients would benefit most from potentially harmful therapies and provides a way to evaluate newer therapies with regard to the amount of ischemic tissue salvaged. OBJECTIVE To operationally define and characterize cerebral tissue at risk for stroke progression. METHODS We retrospectively selected 25 patients with an acute onset of a hemispheric stroke from our database who had undergone a combination of two diffusion-weighted MRI studies and a perfusion-weighted MRI study. We applied a logistic regression model using maps of the relative mean transit time and relative cerebral blood flow (rCBF) as well as three different maps of the relative cerebral blood volume (rCBV) to predict an operationally defined penumbra (region of mismatch between the diffusion lesion on day 1 and its extension 24 to 72 hours later). RESULTS Maps of the rCBF and initial rCBV were significant predictors for identifying penumbral tissue. Our operationally defined penumbral region was characterized by a reduction in the initial rCBV (47% of contralateral control region [CCR]), an increase (163% of CCR) in the total rCBV, and a reduction (37% of CCR) in the rCBF, whereas the operationally defined ischemic core showed a more severe reduction in the rCBF (12% of CCR) and in the initial rCBV (19% of CCR). CONCLUSION These MR indexes may allow the identification and quantification of viable but ischemically threatened cerebral tissue amenable to therapeutic interventions in the hyperacute care of stroke patients.

Survival with the acquired immunodeficiency syndrome. Experience with 5833 cases in New York City.

In a cohort of 5833 subjects in whom the acquired immunodeficiency syndrome (AIDS) was diagnosed in New York City before 1986, the cumulative probability of survival (mean +/- SE) was 48.8 +/- 0.7 percent at one year and 15.2 +/- 1.8 percent at five years. The group with the most favorable survival rate--white homosexual men 30 to 34 years old who presented with Kaposis sarcoma only--had a one-year cumulative probability of survival of 80.5 percent; that group was used as the reference group in assessing the effect of five variables: sex, race or ethnic background, age, probable route of acquiring AIDS (risk group), and manifestations of AIDS at diagnosis. The range in the mortality rate was greater than threefold, depending on these variables. Black women who acquired the disease through intravenous drug abuse, for example, had a particularly poor prognosis. The manifestations of disease at diagnosis had the most influence on survival, accounting on average for 56.3 percent of the excess risk. This variable was followed in importance by age (12.2 percent), race or ethnicity (10.6 percent), risk group (8.4 percent), and sex (8.0 percent), with 4.5 percent of the risk attributable to interactions between variables. When we compared subcohorts based on the year of diagnosis (1981 through 1985), we found a significant improvement in the one-year cumulative probability of survival among subjects with Pneumocystis carinii pneumonia, but not among subjects without P. carinii pneumonia.

Effect of the Dialysis Membrane in the Treatment of Patients with Acute Renal Failure

BACKGROUND The mortality rate among patients with acute renal failure remains high, and the role of the biocompatibility of the dialysis membrane in the resolution of this disorder is not known. METHODS We prospectively studied 72 patients with acute renal failure who required hemodialysis and assigned them to two treatment groups. One group underwent dialysis with the widely used cuprophane dialysis membrane, which activates the complement system and leukocytes, and the other group underwent dialysis with a synthetic polymethyl methacrylate membrane, which has a more limited effect on complement and leukocytes. Scores on the Acute Physiology, Age, and Chronic Health Evaluation (APACHE II) were calculated at the initiation of dialysis. Survival and the recovery of renal function were determined with the use of proportional-hazards and exact logistic-regression analyses. RESULTS When dialysis was initiated, the patients in the two groups were similar in terms of age, APACHE II scores, the prevalence of oliguria, and biochemical indexes of renal failure. Twenty-three of the 37 patients (62 percent) in the group undergoing dialysis with the polymethyl methacrylate membrane recovered renal function, as compared with 13 of the 35 patients (37 percent) in the group undergoing dialysis with the cuprophane membrane (P = 0.04 after adjustment for the APACHE II score). The median number of dialysis treatments required before the recovery of renal function was 5 in the former group and 17 in the latter group (P = 0.02). Twenty-one patients (57 percent) undergoing dialysis with the polymethyl methacrylate membrane survived, as compared with 13 patients (37 percent) undergoing dialysis with the cuprophane membrane (P = 0.11). Of the 20 patients in each group who initially had nonoliguric acute renal failure, the survival rates were 80 percent with the polymethyl methacrylate membrane and 40 percent with the cuprophane membrane (P = 0.01). CONCLUSIONS Among patients with acute renal failure requiring hemodialysis, the use of the polymethyl methacrylate membrane, as compared with the cuprophane membrane, resulted in improved recovery of renal function.

Fall Direction, Bone Mineral Density, and Function: Risk Factors for Hip Fracture in Frail Nursing Home Elderly

PURPOSE To determine the importance of fall characteristics, body habitus, function, and hip bone mineral density as independent risk factors for hip fracture in frail nursing home residents. SUBJECTS AND METHODS In this prospective, case-control study of a single, long-term care facility, we enrolled 132 ambulatory residents (95 women and 37 men) aged 65 and older, including 32 cases (fallers with hip fracture) and 100 controls (fallers with no hip fracture). Principal risk factors included fall characteristics, body habitus, measures of functional assessment, and hip bone mineral density by dual-energy X-ray absorptiometry. RESULTS In multivariate analysis, including only those with knowledge of the fall direction (n=100), those who fell and suffered a hip fracture were more likely to have fallen sideways (odds ratio 5.7, 95% confidence interval [CI] 1.7 to 18, P= 0.004) and have a low hip bone mineral density (odds ratio 1.9, 95% CI 0.97 to 3.7, P=0.06) than those who fell and did not fracture. When all participants were included (n=132) and subjects who did not know fall direction were coded as not having fallen to the side, a fall to the side (odds ratio 3.9, 95% CI 1.3 to 11, P=0.01), low hip bone density (odds ratio 1.8, 95% CI 1.03 to 3, P=0.04), and impaired mobility (odds ratios 6.4, 95% CI 1.9 to 21, P=0.002) were independently associated with hip fracture. Sixty-seven percent of subjects (87% with and 62% without hip fracture) had a total hip bone mineral density greater than 2.5 SD below adult peak bone mass and were therefore classified as having osteoporosis using World Health Organization criteria. CONCLUSIONS Among frail elderly nursing home fallers, the preponderance of whom are osteoporotic, a fall to the side, a low hip bone density, and impairment in mobility are all important and independent risk factors for hip fracture. These data suggest that, among the frailest elderly, measures to reduce the severity of a sideways fall and improve mobility touch on new domains of risk, independent of bone mineral density, that need to be targeted for hip fracture prevention in this high-risk group.

Importance of imaging method over imaging modality in noninvasive determination of left ventricular volumes and ejection fraction: assessment by two- and three-dimensional echocardiography and magnetic resonance imaging.

OBJECTIVES This study sought to determine the concordance between biplane and volumetric echocardiography and magnetic resonance imaging (MRI) strategies and their impact on the classification of patients according to left ventricular (LV) ejection fraction (EF) (LVEF). BACKGROUND Transthoracic echocardiography and MRI are noninvasive imaging modalities well suited for serial evaluation of LV volume and LVEF. Despite the accuracy and reproducibility of volumetric methods, quantitative biplane methods are commonly used, as they minimize both scanning and analysis times. METHODS Thirty-five adult subjects, including 25 patients with dilated cardiomyopathies, were evaluated by biplane and volumetric (cardiac short-axis stack) cine MRI and by biplane and volumetric (three-dimensional) transthoracic echocardiography. Left ventricular volume, LVEF and LV function categories (LVEF > or =55%, >35% to <55% and < or =35%) were then determined. RESULTS Biplane echocardiography underestimated LV volume with respect to the other three strategies (p < 0.01). There were no significant differences (p > 0.05) between any of the strategies for quantitative LVEF. Volumetric MRI and volumetric echocardiography differed by a single functional category for 2 patients (8%). Six to 11 patients (24% to 44%) differed when comparing biplane and volumetric methods. Ten patients (40%) changed their functional status when biplane MRI and biplane echocardiography were compared; this comparison also revealed the greatest mean absolute difference in estimates of EF for those subjects whose EF functional category had changed. CONCLUSIONS Volumetric MRI and volumetric echocardiographic measures of LV volume and LVEF agree well and give similar results when used to stratify patients with dilated cardiomyopathy according to systolic function. Agreement is poor between biplane and volumetric methods and worse between biplane methods, which assigned 40% of patients to different categories according to LVEF. The choice of imaging method (volumetric or biplane) has a greater impact on the results than does the choice of imaging modality (echocardiography or MRI) when measuring LV volume and systolic function.

Early changes in biochemical markers of bone turnover predict the long-term response to alendronate therapy in representative elderly women: a randomized clinical trial.

Although the antiresorptive agent alendronate has been shown to increase bone mineral density (BMD) at the hip and spine and decrease the incidence of osteoporotic fractures in older women, few data are available regarding early prediction of long‐term response to therapy, particularly with regard to increases in hip BMD. Examining short‐term changes in biochemical markers incorporates physiologic response with therapeutic compliance and should provide useful prognostic information for patients. The objective of this study was to examine whether early changes in biochemical markers of bone turnover predict long‐term changes in hip BMD in elderly women. The study was a double‐blind, placebo‐controlled, randomized clinical trial which took place in a community‐based academic hospital. One hundred and twenty community‐dwelling, ambulatory women 65 years of age and older participated in the study. Intervention consisted of alendronate versus placebo for 2.5 years. All patients received appropriate calcium and vitamin D supplementation. The principal outcome measures included BMD of the hip (total hip, femoral neck, trochanter, and intertrochanter), spine (posteroanterior [PA] and lateral), total body, and radius. Biochemical markers of bone resorption included urinary N‐telopeptide cross‐linked collagen type I and free deoxypyridinoline; markers of bone formation included serum osteocalcin and bone‐specific alkaline phosphatase. Long‐term alendronate therapy was associated with increased BMD at the total hip (4.0%), femoral neck (3.1%), trochanter (5.5%), intertrochanter (3.8%), PA spine (7.8%), lateral spine (10.6%), total body (2.2%), and one‐third distal radius (1.3%) in elderly women (all p < 0.01). In the placebo group, bone density increased 1.9–2.1% at the spine (p < 0.05) and remained stable at all other sites. At 6 months, there were significant decreases in all markers of bone turnover (–10% to –53%, p < 0.01) in women on alendronate. The changes in urinary cross‐linked collagen at 6 months correlated with long‐term bone density changes at the hip (r = –0.35, p < 0.01), trochanter (r = –0.36, p < 0.01), PA spine (r = –0.41, p < 0.01), and total body (r = –0.34, p < 0.05). At 6 months, patients with the greatest drop in urinary cross‐linked collagen (65% or more) demonstrated the greatest gains in total hip, trochanteric, and vertebral bone density (all p < 0.05). A 30% decrease in urinary cross‐linked collagen at 6 months predicted a bone density increase of 2.8–4.1% for the hip regions and 5.8–6.9% for the spine views at the 2.5‐year time point (p < 0.05). There were no substantive associations between changes in biochemical markers and bone density in the placebo group. Alendronate therapy was associated with significant long‐term gains in BMD at all clinically relevant sites, including the hip, in elderly women. Moreover, these improvements were associated with early decreases in biochemical markers of bone turnover. Early dynamic decreases in urinary cross‐linked collagen can be used to monitor and predict long‐term response to bisphosphonate therapy in elderly women. Future studies are needed to determine if early assessment improves long‐term patient compliance or uncovers poor compliance, thereby aiding the physician in maximizing the benefits of therapy.

Clinical and Vascular Outcome in Internal Carotid Artery Versus Middle Cerebral Artery Occlusions After Intravenous Tissue Plasminogen Activator

Background and Purpose— Early reperfusion is a predictor of good outcome in acute ischemic stroke. We investigated whether middle cerebral artery (MCA) occlusions have a better clinical outcome and proportion of recanalization compared with internal carotid artery (ICA) occlusion after standard treatment with intravenous (IV) tissue plasminogen activator (tPA). Patients— In a retrospective analysis of our prospective stroke database between January 7, 1998, and January 30, 2002, we identified 36 consecutive patients who were treated with IV tPA within 3 hours after symptom onset of a stroke in the distribution of a documented ICA or MCA occlusion. The National Institutes of Health Stroke Scale (NIHSS) score was recorded before tPA, at 24 hours, 3 days, and 3 months after stroke. Three-month outcome was recorded by modified Rankin scale. Magnetic resonance angiography or computed tomographic angiography was obtained before tPA. The presence of recanalization was assessed by transcranial Doppler and/or magnetic resonance angiography within 3 days after stroke onset. Results— Nineteen patients had MCA occlusion, and 17 had ICA-plus-MCA occlusion before tPA. Although there was no difference in age and NIHSS at day 0 between the 2 groups, the MCA group had a lower day 3 NIHSS score compared with the ICA group (P =0.006) in an ANCOVA. In addition, patients who had a MCA occlusion had lower day 1 and 3 NIHSS scores compared with the ICA group (P =0.04 and P =0.03, respectively; Wilcoxon rank sum). Similarly, NIHSS was significantly lower in patients who recanalized on days 1 and 3 (P =0.004 and P =0.003 respectively, Wilcoxon rank sum). When we adjusted for NIHSS score at day 0 in an ANCOVA, the adjusted mean was lower in the group that recanalized compared with the group that did not recanalize (P <0.001). There was a significant difference between the proportion of recanalization in the MCA group (15 of 17 recanalized, 88%) at 3 days after tPA compared with that of the ICA group (5 of 16 recanalized, 31%;P =0.001, Fisher exact test). The 3-month modified Rankin scale was not different between the 2 groups. Conclusions— Despite comparable age and NIHSS scores before IV tPA, MCA occlusions have lower day 1 and 3 NIHSS scores and higher proportion of recanalization compared with ICA occlusions. A combined IV/intra-arterial or mechanical thrombolysis may be needed to achieve early recanalization in ICA occlusions.

Endothelial Function in Human Immunodeficiency Virus-Infected Antiretroviral-Naive Subjects Before and After Starting Potent Antiretroviral Therapy: The ACTG (AIDS Clinical Trials Group) Study 5152s

OBJECTIVES This study evaluated the effects of 3 class-sparing antiretroviral therapy (ART) regimens on endothelial function in human immunodeficiency virus (HIV)-infected subjects participating in a randomized trial. BACKGROUND Endothelial dysfunction has been observed in patients receiving ART for HIV infection. METHODS This was a prospective, multicenter study of treatment-naive subjects who were randomly assigned to receive a protease inhibitor-sparing regimen of nucleoside reverse transcriptase inhibitors (NRTIs) + efavirenz, a non-nucleoside reverse transcriptase inhibitor-sparing regimen of NRTIs + lopinavir/ritonavir, or a NRTI-sparing regimen of efavirenz + lopinavir/ritonavir. The NRTIs were lamivudine + stavudine, zidovudine, or tenofovir. Brachial artery flow-mediated dilation (FMD) was determined by B-mode ultrasound before starting on ART, then after 4 and 24 weeks. RESULTS There were 82 subjects (median age 35 years, 91% men, 54% white). Baseline CD4 cell counts and plasma HIV ribonucleic acid (RNA) values were 245 cells/mm(3) and 4.8 log(10) copies/ml, respectively. At baseline, FMD was 3.68% (interquartile range [IQR] 1.98% to 5.51%). After 4 and 24 weeks of ART, plasma HIV RNA decreased by 2.1 and 3.0 log(10) copies/ml, respectively. FMD increased by 0.74% (IQR -0.62% to +2.74%, p = 0.003) and 1.48% (IQR -0.20% to +4.30%, p < 0.001), respectively, with similar changes in each arm (Kruskal-Wallis p value >0.600). The decrease in plasma HIV RNA at 24 weeks was associated with greater FMD (r(s) = -0.30, p = 0.017). CONCLUSIONS Among treatment-naive individuals with HIV, 3 different ART regimens rapidly improved endothelial function. Benefits were similar for all ART regimens, appeared quickly, and persisted at 24 weeks.

Histologic predictors of renal cell carcinoma response to interleukin-2-based therapy.

The authors examined pathology from patients with renal cancer (RCC) treated with IL-2 to determine response rates for clear cell and variant RCC and to identify histologic features that predict response. Pathology specimens were reviewed by a single pathologist who was blinded to both the prior pathology interpretation and the therapeutic response. Findings were correlated with response to IL-2 therapy. Evaluable pathology specimens were obtained from 231 patients. Of 163 primary RCCs, the response rate was 21% (30/146) for patients with clear cell versus 6% (1/17) for patients with variant or indeterminate type RCC (P = 0.20). For clear cell carcinomas, response to IL-2 was associated with the presence of alveolar features and the absence of papillary and granular features. Patients with more than 50% alveolar features and no granular or papillary features had a 39% response rate (14/36). Patients with alveolar and granular features representing less than 50% of the specimen and no papillary features had a 19% response rate (15/77). The response rate for the others was 3% (1/33). This model was then applied to an independent sample of 68 metastasis specimens. Response rates in the three prognostic groups and for patients with non-clear cell cancers were 25% (5/20), 9% (2/22), 0% (0/16), and 0% (0/10), respectively. Median survivals for all patients with clear cell tumors by risk group were 2.87, 1.36, and 0.87 years, respectively (P < 0.001). These data suggest that patients with non-clear cell RCC or with clear cell RCC with papillary, no alveolar, and/or more than 50% granular features respond poorly to IL-2 and should be considered for alternative treatments. Investigation of other tumor-related predictors of IL-2 responsiveness is warranted.