Annapurni Jayam-Trouth

Predictors of highly prevalent brain ischemia in intracerebral hemorrhage

This study was undertaken to determine the prevalence, characteristics, risk factors, and temporal profile of concurrent ischemic lesions in patients with acute primary intracerebral hemorrhage (ICH).

Association of Physical Activity Level and Stroke Outcomes in Men and Women: A Meta-Analysis

OBJECTIVE The protective effect of physical activity (PA) on risk of stroke remains controversial as a result of lack of insight into the sources of heterogeneity between studies. We performed a comprehensive meta-analysis of studies to (1) quantify the association between PA level and risk of stroke outcomes and (2) test the hypothesis that the association of PA level with stroke outcomes will be similar between men and women. The outcome measures are stroke incidence, stroke mortality, or both. METHODS Cohort studies were identified by searching MEDLINE and EMBASE (from 1986 to 2005) and meta-analysis conducted according to meta-analysis of Observational Studies in Epidemiology (MOOSE) group recommendations. Data were reported as pooled relative risk (RR) and 95% confidence intervals (CI) using random-effects models to assess the association of stroke outcomes with PA level. Heterogeneity was investigated, and sensitivity analysis was performed. Stratified analysis by gender was performed. RESULTS Of 992 articles, 13 satisfied all eligibility criteria and were studied. Compared with low PA, moderate PA caused an 11% reduction in risk of stroke outcome (RR = 0.89, 95% CI 0.86-0.93, p < 0.01) and high PA a 19% reduction (RR = 0.81, CI 0.77-0.84, p < 0.01). Among the men, results showed a 12% reduction in risk associated with moderate PA (RR = 0.88, CI 0.82-0.94, p < 0.01) and 19% reduction for high PA (RR = 0.81, CI 0.75-0.87, p < 0.01). Among the women, results showed a 24% reduction in risk for high PA (RR = 0.76, CI 0.64-.89, p < 0.01). There was, however, no significant risk reduction associated with a moderate PA level in women. CONCLUSIONS Increased PA level appears beneficial in reduction of risk of stroke and related outcomes. However, higher levels of PA may be required in women to achieve as significant a risk reduction as in men. An exercise regimen tailored to women to improve related physiological mechanisms will likely be beneficial.

Neuronal expression of bitter taste receptors and downstream signaling molecules in the rat brainstem

Previous studies have shown that molecules of the taste transduction pathway may serve as biochemical markers for chemoreceptive cells in respiratory and gastrointestinal tracts. In this study, we tested the hypothesis that brainstem neurons contain signaling molecules similar to those in taste buds which may sense the chemical composition of brain extracellular fluids. We used the reverse transcription polymerase chain reaction (RT-PCR), Western blot and immunohistochemical techniques to evaluate presence of different bitter-responsive type 2 taste receptors (T2Rs), their associated G-protein α-gustducin, the downstream signaling molecules phospholipase C isoform β2 (PLC-β2) and transient receptor potential melastatin 5 (TRPM5) in the brainstem of rats. RT-PCR confirmed the mRNA coding for α-gustducin, PLC-β2, TRPM5 and rT2R1 but not that of rT2R16, rT2R26 and rT2R38 in the medulla oblongata. Western blotting confirmed the presence of α-gustducin at the protein level in rat brainstem. Immunohistochemistry identified cells expressing α-gustducin and PLC-β2 at multiple cardiorespiratory and CO(2)/H(+) chemosensory sites, including rostral ventral medulla, facial, parapyramidal, solitary tract, hypoglossal and raphe nuclei. In the medullary raphe, α-gustducin and PLC-β2 were colocalized with a subpopulation of tryptophan hydroxylase (TPH)-immunoreactive serotonergic neurons, a subset of which has respiratory CO(2)/H(+) chemosensitivity. Presence of the T2R1 gene and other genes and proteins of the bitter taste transduction pathway in the brainstem implies additional functions for taste receptors and their effector molecules apart from their gustatory function.

Association of Chronic Kidney Disease With Cerebral Microbleeds in Patients With Primary Intracerebral Hemorrhage

Background and Purpose— To investigate the relationship between chronic kidney disease (CKD) and MRI-defined cerebral microbleeds (CMB), a harbinger of future intracerebral hemorrhage (ICH), among patients with a recent history of primary ICH. Methods— Using data from a predominantly black cohort of patients with a recent ICH-enrolled in an observational study between September 2007 and June 2011, we evaluated the association between CKD (defined as estimated low glomerular filtration rate<60 mL/min per 1.73 m2) and CMB on gradient-echo MRI. Multivariable models were generated to determine the contribution of CKD to the presence, number, and location of CMB. Results— Of 197 subjects with imaging data, mean age was 59 years, 48% were women, 73% were black, 114 (58%) had ≥1 CMBs, and 52 (26%) had CKD. Overall, CKD was associated with presence of CMB (adjusted odds ratio, 2.70; 95% confidence interval [CI], 1.10–6.59) and number of CMB (adjusted relative risk, 2.04; 95% CI, 1.27–3.27). CKD was associated with CMB presence (adjusted odds ratio, 3.44; 95% CI, 1.64–7.24) and number (adjusted relative risk, 2.46; 95% CI, 1.11–5.42) in black patients, but not CMB presence (adjusted odds ratio, 3.00; 95% CI, 0.61–14.86) or number (adjusted relative risk, 1.03; 95% CI: 0.22–4.89) in non-Hispanic white patients (interactions by race were statistically not significant). Conclusions— CKD is associated with a greater presence and number of CMB in ICH patients, particularly in patients of black race. Future studies should assess whether low estimated glomerular filtration rate may be a CMB risk marker or potential therapeutic target for mitigating the development of CMB.

Racial Disparities in Tissue Plasminogen Activator Treatment Rate for Stroke A Population-Based Study

Background and Purpose— Some prior studies have shown that racial disparities exist in intravenous tissue plasminogen activator (tPA) use for acute ischemic stroke. We sought to determine whether race was associated with tPA treatment for stroke in a predominantly black urban population. Methods— Systematic chart abstraction was performed on consecutive hospitalized patients with ischemic stroke from all 7 acute care hospitals in the District of Columbia from February 1, 2008, to January 31, 2009. Results— Of 1044 patients with ischemic stroke, 74% were black, 19% non-Hispanic white, and 5% received intravenous tPA. Blacks were one third less likely than whites to receive intravenous tPA (3% versus 10%, P<0.001). However, blacks were also less likely than whites to present within 3 hours of symptom onset (13% versus 21%, P=0.004) and also less likely to be tPA-eligible (5% versus 13%, P<0.001). Of those who presented within 3 hours, blacks were almost half as likely to be treated with intravenous tPA than whites (27% versus 46%, P=0.023). The treatment rate for tPA-eligible patients was similar for blacks and whites (70% versus 76%, P=0.62). Conclusions— In this predominantly black urban population hospitalized for acute ischemic stroke, blacks were significantly less likely to be treated with intravenous tPA due to contraindications to treatment, delayed presentation, and stroke severity. Effective interventions designed to increase treatment in this population need to focus on culturally relevant education programs designed to address barriers specific to this population.

Co-expression of nAChRs and molecules of the bitter taste transduction pathway by epithelial cells of intrapulmonary airways.

AIMS The ability to sense the bitter taste of nicotine is an important component of addiction to, and withdrawal from, cigarette smoking. alpha-Gustducin and phospholipase C-beta2 (PLC-beta2), molecules involved in the taste transduction pathway, have been identified in airway epithelial solitary chemosensory cells (SCCs). Airway epithelial cells also express multiple nicotinic acetylcholine receptors (nAChRs). However, the relationship between nAChRs and molecules of taste transduction in response to nicotine is not known. This study was designed to determine whether nAChRs and the taste transduction molecules alpha-gustducin, PLC-beta2 and bitter taste receptors (T2R38) reside at sites of the intrapulmonary airways where interaction with the nicotine components of cigarette smoke is likely. MAIN METHODS We used the reverse transcription-polymerase chain reaction (RT-PCR) to detect alpha-gustducin, PLC-beta2 and T2R38 mRNA and immunohistochemistry to localize expression of these proteins by nAChR expressing cells of the airway. KEY FINDINGS RT-PCR demonstrated the presence of mRNA for alpha-gustducin, PLC-beta2 and T2R38. Immunohistochemistry showed the expression of alpha-gustducin, PLC-beta2 and T2R38 by subsets of epithelial cells at all levels of the intrapulmonary airways including bronchi, terminal and respiratory bronchioles. Double labeling demonstrated the co-expression of alpha-gustducin with alpha3, alpha4, alpha5, alpha7 and beta2, as well as, PLC-beta2 and T2R38 with alpha4, alpha5 and beta2 nAChR subunits. SIGNIFICANCE These findings provide morphological evidence for the presence of molecules of the bitter taste transduction pathway in nAChR expressing SCCs of the intrapulmonary airways. These SCCs may, thus, constitute a peripheral component of the bitter taste signal transduction pathway for nicotine.

Preventing Recurrence of Thromboembolic Events through Coordinated Treatment in the District of Columbia

Rationale PROTECT DC examines whether stroke navigators can improve cardiovascular risk factors in urban underserved individuals newly hospitalized for stroke or ischemic attack. Within one-year of hospital discharge, up to one-third of patients no longer adhere to secondary prevention behaviors. Adherence rates are lower in minority-underserved groups, contributing to health disparities. In-hospital programs increase use of stroke prevention therapies but may not be as successful in underserved individuals. In these groups, low literacy, limited healthcare access, and sparse community resources may reduce adherence. Lay community health workers (navigators) improve adherence in other illnesses through education and assisting in overcoming barriers to achieving desired health behaviors and obtaining needed healthcare services. Aims and design PROTECT DC is a Phase II, single-blind, randomized, controlled trial comparing in-hospital education plus stroke navigators to usual care. Atherogenic ischemic stroke and transient ischemic attack survivors are recruited from Washington, DC hospitals. Navigators meet with participants during the index hospitalization, perform home visits, and meet by phone. They focus on stroke education, medication compliance, and overcoming practical barriers to adherence. The interventions are driven by the theories of reasoned action and planned behavior. Study outcomes The primary dependent measure is a summary score of four objective measures of stroke risk factor control: systolic blood pressure, low-density lipoprotein, hemoglobin Hb A1C, and antiplatelet agent pill counts. Secondary outcomes include stroke knowledge, exercise, dietary modification, and smoking cessation. Conclusion PROTECT DC will determine whether a Phase III trial of stroke navigation for urban underserved individuals to improve adherence to secondary stroke prevention behaviors is warranted.

Acute Ischemic Stroke Secondary to Iron Deficiency Anemia: A Case Report

A rare case of acute ischemic stroke in a young patient with iron deficiency anemia (IDA) is reported. IDA has been suggested to have an association with stroke, but few cases have proven it thus far. Three physiological mechanisms explaining IDA to ischemic stroke include a hypercoagulable state secondary to IDA, thrombocytosis secondary to IDA, and anemic hypoxia induced by IDA. Our paper shows an example of a hypoxia-induced stroke secondary to IDA in a young woman with menorrhagia. Thrombus formation was ruled out as the Magnetic Resonance Angiogram (MRA) showed no evidence. As all other known causes for stroke were ruled out, the patients IDA is a reasonable cause for her stroke. Iron deficiency decreases the amount of hemoglobin, which consequently decreases the amount of oxygen in the blood resulting in low-oxygen delivery to the brain. This causes hypoxic conditions in the brain, leading to death of brain tissue. Thus, we suggest a possible relationship between IDA and ischemic stroke in young adults. Considering IDA as one of the risk factors for ischemic stroke and treating with timely transfusions would be an important step one can take to prevent stroke.

A rare case of occipital stroke as a consequence of nonbacterial thrombotic endocarditis in ovarian clear cell carcinoma: a case report.

Hypercoagulability occurs in 15% of patients with malignancy and represents a clinical spectrum ranging from abnormal coagulation tests but no clinically evident thromboembolic disease, to arterial and venous thrombosis, migratory thrombophlebitis, nonbacterial thrombotic endocarditis (NBTE) and disseminated intravascular coagulation. The combination of increased procoagulant activity and decreased fibrinolytic activity accelerates the prothrombotic potential of endothelial cells in malignancy. NBTE is a rare manifestation of cancer-induced hypercoagulability and is commonly seen with mucin-producing adenocarcinomas, but rarely seen with ovarian clear cell carcinoma (OCCC). Cerebrovascular embolization ranges from 14–91% in NBTE. We report a rare case of a 62-year-old female presenting with occipital stroke as a consequence of NBTE in OCCC. Association of NBTE in OCCC has only been reported in 2 cases so far, but presentation with stroke has never been reported in the literature.

Neuroanatomical Relationships of Substance P-Immunoreactive Intrapulmonary C-Fibers and Nicotinic Cholinergic Receptors

Previous studies have suggested that sensory mechanisms may be important components of addiction to, and withdrawal from, cigarette smoking. The sensory and respiratory responses to nicotine are mediated, in part, by bronchopulmonary C‐fiber afferents. Nicotine has a direct stimulatory effect on pulmonary sensory neurons, and nicotinic cholinergic receptors (nAChRs) composed of various combinations of α and β subunits are known to be present in pulmonary ganglia. At the subcellular level, however, little is known about expression of nAChRs on sensory fibers in the intrapulmonary airways. The present study was therefore designed to evaluate the expression of nAChRs on a subset of intrapulmonary sensory nerve endings known to exhibit immunoreactivity for substance P (SP). The presence of nAChR subunits was first confirmed at the mRNA and protein levels in rat lung tissues by using RT‐PCR and Western blot techniques. Then, double labeling of SP‐immunoreactive (‐IR) C‐fibers and different nAChR subunits was performed. α2, α3, α4, α5, α7, and β2 subunits were detected at all levels of the intrapulmonary airways; including bronchi, terminal and respiratory bronchioles, alveolar walls, and alveolar macrophages. None of the nAChR subunits studied was expressed by the SP‐IR C‐fibers. However, SP‐expressing C‐fibers were observed in close proximity to and intermingling with nAChR‐expressing airway epithelial cells. The close proximity of C‐fibers to nAChR‐expressing airway epithelial cells suggests that a component of nicotinic stimulation of SP‐IR C‐fiber afferents may be mediated by endogenous chemical substances released by nAChR‐expressing epithelial cells.