bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 71: Ca
2+
Reuptake is Reduced in the Absence of Insulin Receptors in Mouse Cardiomyocytes
Authors: Torres Natalia S , Nguyen Yennhi , Lopez-Izquierdo Angelica , Spitzer Kenneth
Published: March 2022

Left ventricle diastolic dysfunction (LVDD), characterized by slow or incomplete relaxation of the ventricle during diastole, is an important contributor to heart failure development in diabetic patients. LVDD can be found in pre-diabetic patients as well as in almost half of asymptomatic patients with well-controlled diabetes. Reduced Ca
2+
reuptake into the sarcoplasmic reticulum (SR) by the SR Ca
2+
ATPase (SERCA) is an important contributor to the slow relaxation observed in diastolic dysfunction. Despite this there are still conflicting results with respect to SERCA expression and function in animal models of diabetes, due perhaps to differences in the duration and severity of diabetes and the presence of systemic complications that can per se alter SERCA expression and/or function. Here, we tested the hypothesis that the impaired relaxation observed in diabetic mice is a consequence of the direct effect of insulin on SERCA. We measured Ca
2+
transient relaxation in isolated cardiomyocytes from 8 weeks cardiomyocyte-selective insulin receptor knockout (CIRKO) mice (Cre-IR

lox

/

lox

),
,
which lack systemic complications, and compared them with their WT littermates (IR

lox

/

lox
)

. Cardiomyocytes loaded with the Ca
2+
dye Fluo-4 were field stimulated at 2 and 3.3 Hz, at 37°C. The intracellular Ca
2+
was monitored using a custom-made epifluorescence system. SERCA and Na
+
/Ca
2+
exchanger (NCX) expression level was reported as the fold change relative to WT. We found that Ca
2+
transient relaxation was prolonged at both frequencies in CIRKO compared with WT, while retaining a normal frequency-dependent acceleration of relaxation. The exponential time constants were 104±4 (WT) vs. 190±16 (CK) ms at 3.3 Hz, n= 20/group, p<0.001 and 111±6 (WT) vs. 226±19 (CK) ms at 2 Hz, n= 20/group, p<0.001). We also found a reduction in SERCA expression (mRNA: 0.65±0.03, n=10, p<0.001; protein:0.62±0.11, n=4, p<0.05) with no difference in NCX expression (mRNA: 0.92±0.06 n=10/group, p=0.5; protein 0.96±0.05, n=6/group, p=0.2). In conclusion, our findings suggest that the slower Ca
2+
removal observed in the systemic models of diabetes is a direct effect of insulin on SERCA, which could contribute to the LVDD observed in diabetic patients.
Abstract 74: Whole Genome Sequencing as a Diagnostic Tool for Cardiomyopathy
Authors: Pan Wenyu , Puckelwartz Megan J , Dellefave-Castillo Lisa , Pesce Lorenzo L , McNally Elizabeth M
Published: March 2022

Background:
Congestive heart failure (CHF) is an increasing medical problem that is disabling and costly, and CHF currently affects more than 5 million Americans. A leading cause of CHF is cardiomyopathy, a disorder with a high heritable component. Genetic studies of familial cardiomyopathy have identified more than 50 responsible genes. Knowledge of the genetic underpinnings of disease provides prognostic information and can guide clinical decision- making. Clinical genetic testing employs gene panels for diagnosis, and typical panels include 20-100 genes. We assessed the viability of whole genome sequencing (WGS) to identify potentially pathogenic cardiomyopathy-associated genetic variants in established and novel genes.

Methods:
WGS was conducted on 91 families (99 individuals) with cardiomyopathy. In 46/91 (50%) families, there was a prior history of unrevealing panel-based clinical genetic testing. WGS was performed using Illumina next generation sequencing. Variants were called and annotated using MegaSeq and MegaSeq2. MegaSeq2 refines the number of candidate variants from ~4 million to <30 using variant effect prediction, conservation at variant site, frequency, and expression data.

Results:
MegaSeq2 was applied to 99 cardiomyopathy genomes and in 45/91 families (49%), a potentially pathogenic or likely pathogenic variant was identified. Here we describe identification and segregation analysis in 4 families. Two families have unique
RBM20
variants that segregate with cardiomyopathy. One family was found to carry a premature stop in
SCN5A
and exhibits variable phenotypes including sudden death, arrhythmia and cardiomyopathy. The fourth family has cardiomyopathy that segregates with a
BAG3
early termination variant.

Conclusions:
WGS was able to identify potentially pathogenic variants in nearly half (45/91). While some of the variants identified were in novel genes, the majority of pathogenic variants were in established cardiomyopathy genes despite previous panel-based testing. More comprehensive analysis, like WGS, allows for re-evaluation of variation as additional genetic information becomes available.
Abstract 89: Differences in Orexin-related Gene Expression in the Brain in Early versus Late Stage Heart Failure in Male Rats
Authors: Watkins Jacqueline , Vu Jennifer , Hayward Linda
Published: March 2022

Orexin is a neuropeptide produced exclusively by neurons in the lateral hypothalamus. Orexinergic neurons send projections throughout the brain and the system has been hypothesized to be critical for the coordination of “survival related-processes. Emerging evidence has identified that the orexin system is dysregulated in several forms of cardiovascular disease. In hypertension for example, upregulation of the orexin system contributes to elevated sympathetic drive. In heart failure, genomic changes in the orexin type 2 receptor have been linked to reduced cardiac function and pretreatment with an orexin type 2 receptor agonist prior to cardiac stress was identified to be cardio-protective. These data suggest changes in orexin system activation before or during cardiac stress may have therapeutic potential. The present study was undertaken to evaluate changes in the brain orexin system at 4 weeks following myocardial injury compared to the chronic changes previous documented at 16 weeks post infarction.

Methods:
Adult male rats underwent either sham operation (n=9) or ligation of the left main coronary artery (n=9) while under anesthesia and were allowed to recover either 4 weeks or 16 weeks.

Results:
The infarct size ranged from 21 to 39% of the left ventricle (28+/-6%, mean+/-STDEV). At 4 weeks of age hypothalamic orexin gene expression was upregulated 54% (P<0.07) when compared to sham operated animals. This was in contrast to a 78% reduction in gene expression at 16 weeks following myocardial infarction. No significant difference in orexin receptor expression (type 1 or type 2) within the hypothalamus was identified at either time point. These findings demonstrate that the orexin system undergoes dynamic changes following myocardial insult. Since orexin supplementation has been reported to be both neuroprotective and cardioprotective, it is possible that early orexin upregulation is an adaptive/protective response and sustained stimulation of the orexin system over a longer time period may improve health outcomes associated with heart failure.
Abstract 91: Cardiac-directed Expression of Adenylyl Cyclase Catalytic Domain Reduces Left Ventricular Systolic and Diastolic Dysfunction in Pressure-overload
Authors: Tan Zhen , Kim Young Chul , Lai Ngai C , Fu Zhenxing , Giamouridis Dimosthenis , Guo Tracy , Xia Bing , Gao Mei Hua , Hammond H. Kirk
Published: March 2022

Background and Objective:
A fusion protein (C1C2) constructed by fusing the intracellular C1 and C2 segments of adenylyl cyclase type 6 (AC6), retains beneficial effects of AC6 expression, without increasing cAMP generation. For example, transgenic mice with cardiac-directed C1C2 expression have normal left ventricular (LV) function despite reduced cAMP generation. Furthermore, sustained isoproterenol (Iso) infusion reduces LV function in normal mice, but, in contrast, C1C2 mice show
increased
LV function with sustained Iso infusion. The effects of C1C2 expression in pressure-overload is unknown.

Methods:
LV pressure overload was induced by transaortic constriction (TAC) in C1C2 mice and in transgene negative mice. Three weeks after TAC, LV systolic and diastolic function were measured, and Ca2+ handling was assessed in isolated cardiac myocytes.

Results:
C1C2 expression reduced LV hypertrophy (p=0.017), increased LV peak pressure development (+dP/dt, p=0.018), and improved LV peak pressure decay (-dP/dt, p=0.038) in the pressure-overload (
Table
). Cytosolic peak Ca2+ concentration was increased (p=0.047), and time to peak Ca2+ transient and Tau were decreased (p=0.002 and p=0.003, respectively) in cardiac myocytes isolated from pressure-overloaded hearts (
Table
).

Conclusions:
Cardiac-directed C1C2 expression reduces LV hypertrophy, improves Ca2+ handling, and increases LV systolic and diastolic function in pressure-overload. These data provide a rationale for further exploration of C1C2 gene transfer as a potential treatment for heart failure.
Abstract 92: Cardiac Bridging Integrator 1 Gene Transfer Improves Left Ventricular Lusitropy in Mice With Continuous Infusion of Isoproterenol
Authors: Liu Yan , Zhou Kang , Agavanian Sosse , Xu Bing , Shaw Robin M , Hong TingTing
Published: March 2022

Background:
Cardiac bridging integrator 1(cBIN1) is a membrane scaffolding protein, which organizes t-tubule dyad microdomains critical for normal calcium transient development. BIN1 is transcriptionally reduced in heart failure, and reduced BIN1 diminishes calcium transients, limiting excitation-contraction coupling and impairing contractility. Furthermore, cBIN1-microdomains organize with acute β-adrenergic activation. It remains unclear whether over-expression of cBIN1 improves myocardial function in mice with chronic sympathetic overdrive.

Methods:
Adult male C57BL/6 mice received retro-orbital injections of adeno-associate virus 9 (AAV9) transducing either control GFP, sBIN1 (small BIN1), BIN1+13, BIN1+17, or cBIN1 (BIN1+13+17). Three weeks after virus injection, mice were subjected to subcutaneous implantation of micro osmotic pumps continuously releasing isoproterenol at 30mg /kg/day for four weeks. Left ventricular (LV) geometry and function were evaluated by echocardiography before and weekly after isoproterenol infusion.

Results:
In the control GFP group, isoproterenol infusion significantly increased LV mass and relative wall thickness (RWT), consistent with concentric hypertrophy. Over-expression of any of the four BIN1 isoforms attenuated left ventricular hypertrophy (n=5 per group). However, only cBIN1 over-expressing mice became more efficient. Their hearts had improved left ventricular relaxation, and were able to preserve ejection fraction yet with increased end systolic and diastolic volumes. As a result of improved relaxation, cBIN1 over-expression increased stroke volume and cardiac output without their hearts becoming hyperdynamic. Thus cBIN1 conveys a general BIN1 protection against isoproterenol induced hypertrophy together with a cBIN1 specific improvement in lusitropy.

Conclusions:
In mice with chronic sympathetic overdrive, over-expression of cBIN1 increases LV compliance, preserves heart lusitropy, and improves cardiac function. This athletic heart like phenotype induced by
cBin1
gene therapy indicates that exogenous cBIN1 can reverse the diastolic dysfunction associated with sympathetic overdrive and heart failure progression.
Evidence for a Renal Vascular Mechanism in Renin Release: New Observations with Graded Stimulation by Aortic Constriction
Authors: BLAINE EDWARD H. , DAVIS JAMES O.
Published: March 2022

To examine the possibility of a renal intravascular receptor for renin secretion, bilateral ureteral ligation and a two-hour period of renal ischemia were used to produce a nonfiltering kidney model in dogs. In conscious animals with both innervated and denervated, nonfiltering kidneys, hemorrhage and suprarenal aortic constriction produced significant increases in plasma renin activity. To measure renin secretion directly, a unilateral, nonfiltering kidney was produced, and renal blood flow was determined with a square-wave electromagnetic flowmeter in anesthetized dogs. Renin secretion was significantly elevated after a 20 ml/kg hemorrhage in these animals. In another group of dogs, adrenalectomy was combined with renal denervation in the unilateral, nonfiltering kidney model. In these animals hemorrhage produced significant increases in renin secretion. After a recovery period three of these dogs were subjected to graded constriction of the suprarenal aorta. Slight decreases in blood pressure with and without decreases in renal blood flow produced increases in renin secretion. Since increased renin secretion occurred in the absence of sodium delivery to the macula densa, from denervated kidneys, and without the major portion of circulating catecholamines, it is suggested that an intrinsic receptor for renin release is present within the renal vascular tree.
18-Hydroxy-Deoxycorticosterone in Human Hypertension
Authors: MELBY JAMES C. , DALE SIDNEY L. , WILSON THOMAS E.
Published: March 2022

18-Hydroxy-ll-deoxycorticosterone (18-OH-DOC) was isolated from human adrenal vein blood in concentrations of the same magnitude as is aldosterone, and its structure was proved by a variety of methods including mass spectral analysis. Angiotensin infusions failed to evoke a rise in 18-OH-DOC secretion, whereas ACTH increased 18-OH-DOC secretion up to 20-fold. The secretion rate of 18-OH-DOC determined by isotope dilution in healthy subjects was similar to the range of aldosterone secretion. Excretion of the ring A reduced glucuronide metabolite, 18-hydroxy-tetrahydro-deoxycorticosterone (18-OH-TH DOC), in urine proved to be a valid index of secretion of 18-OH-DOC. 18-OH-DOC secretion was estimated in a variety of hypertensive disorders and found to be significantly elevated in a few (3 of 12) patients with essential hypertension, suppressed plasma renin activity, low or normal aldosterone secretion, and who had significant reduction in blood pressure with spironolactone. A single patient became normotensive on prolonged dexamethasone suppression of ACTH and 18-OH-DOC secretion. The possibility that 18-OH-DOC is a precursor of some more oxygenated and, perhaps, more active mineralocorticoid is suggested.
18-Hydroxy-Deoxycorticosterone Secretion in Experimental Hypertension in Rats
Authors: RAPP JOHN P. , DAHL LEWIS K.
Published: March 2022

Adrenal steroidogenesis was studied in vitro and in vivo in rats which have been specifically bred for susceptibility (S strain) or resistance (R strain) to the hypertensive effects of salt. A marked quantitative difference was found between S and R rats in the adrenal biosynthetic pathways which are subsequent to deoxycorticosterone (DOC). There was a twofold difference in the ability to 18-hydroxylate DOC to form 18-hydroxy-deoxycorticosterone (18OH-DOC) with the greater activity in the S rats. This increment in 18-hydroxylation of DOC in S over R rats was offset by an equal decrement in 11β-hydroxylation of DOC to form corticosterone (B) in S compared with R rats. These alterations in metabolic pathways gave rise to characteristic 18OH-DOC/B ratios for S and R animals that were obvious both in vitro and in vivo.

The data suggest, therefore, that in selectively breeding rats on the basis of blood pressure response to salt, a gene (or genes) which affects the 18OH-DOC/B ratio has been segregated in the S and R strains. Although this segregation is in itself good evidence for an effect of 18OH-DOC (or 18OH-DOC/B ratio) on blood pressure in rats, it was also emphasized that there is evidence for more than one gene affecting blood pressure in rats. Thus, the steroid difference described is likely to be controlled by only one of several genes affecting the quantitative character of blood pressure. Comparison of 18OH-DOC/B ratios in S and R strains with other strains of rats showed that the high ratio in S rats was quite common, but that the low ratio in R rats was rather unique. Thus, it seems that the low 18OH-DOC/B ratio of R animals connotes resistance to salt, while the higher ratio in S and unselected strains probably only connotes normal susceptibility to salt. The extreme sensitivity of S rats to salt must therefore be accounted for by other genes.
Malignant Hypertension: Effect of Therapy on Renin and Aldosterone
Authors: MCALLISTER R. G. , VAN WAY CHARLES W. , DAYANI KIOOMARS , ANDERSON WILLIAM J. , TEMPLE EUGENE , MICHELAKIS ANDREW M. , COPPAGE WILLIAM S. , OATES JOHN A.
Published: March 2022

Plasma renin activity (PRA) and aldosterone secretion rate (ASR) were measured in 22 patients in balance on a 100 mEq sodium diet during the malignant phase of hypertension and at intervals during long-term follow-up on pharmacological therapy. Three patients had normal PRA and ASR during malignant hypertension. Eighty-six per cent of patients had an increased ASR, but only in 36% was PRA concomitantly increased during malignant hypertension (one patient developed elevated PRA in the postmalignant period). PRA fell to normal in 87% of patients after antihypertensive therapy. ASR fell to normal on drug therapy in six patients, and in all of these there was a period during the postmalignant phase in which ASR was increased while PRA was normal or suppressed. In addition to this group with reversible hyperaldosteronism, all but two of the remaining patients with elevated ASR had periods during which ASR was increased at the same time that PRA was normal or suppressed. These data raise the possibility that either a nonrenin aldosterone-stimulating hormone is secreted in malignant hypertension or that excessive stimulation of the adrenal by angiotensin can lead to persistent hyperfunction of aldosterone-secreting cells with a quantitatively deranged feedback control. One patient had an aldosterone-secreting adenoma and had manifestations of the hyperaldosteronism antedating the development of malignant hypertension.
Further Evidence for a Humoral Natriuretic Factor
Authors: BLYTHE WILLIAM B. , D'AVILA DOMINGOS , GITELMAN HILLEL J. , WELT LOUIS G. , LEE LING
Published: March 2022

Experiments were performed in dogs, utilizing cross-circulation techniques, to examine the role of humoral factors in the production of the diminished
net
renal tubular reabsorption of sodium that is provoked by the expansion of the extracellular fluid volume. When the extracellular fluid volume of one of a pair of dogs (donor) was expanded by the intravenous infusion of isotonic saline, the rate of sodium excretion (U
Na
V) increased in the nonexpanded animal (recipient) as well as in the donor. Although the increase in U
Na
V of the recipients was statistically significant, its magnitude was approximately one-fifth of that of the donors. Modified cross-circulation experiments were designed in order to increase the blood flow from the donor dog to the kidneys of the recipient and from the recipient dog to the kidneys of the donor. This modification resulted in a greater increase in U
Na
V in the recipient and a lesser increase in U
Na
V in the donor when the donor was infused intravenously with isotonic saline so that the magnitudes of increase in U
Na
V in donor and recipient were not statistically significantly different. Neither dilution per se of the extracellular fluid of the donor nor passage of time resulted in an increased U
Na
V in donors and recipients. Expansion of the blood volume of the donors by the infusion of whole blood resulted in an increased U
Na
V in the donors but not in the recipients. It is concluded that a humoral factor is responsible, at least in part, for the natriuresis that accompanies the intravenous infusion of isotonic saline and that elaboration of the factor is not a consequence solely of either simple dilution of the extracellular fluid or expansion of the blood volume.
Effects of Angiotensin Infusion on Catecholamine Uptake and Reactivity in Blood Vessels
Authors: KHAIRALLAH PHILIP A. , DAVILA D. , PAPANICOLAOU N. , GLENDE N. M. , MEYER PHILIPPE
Published: March 2022

The interrelations between angiotensin and catecholamine uptake have been studied in rats. Angiotensin was infused for either 5, 30, or 120 minutes at three dose levels: 1, 12, and 45 ng/kg/min. With short exposures to angiotensin, effects were seen in kidney, uterus, and adrenal gland. These organs had been previously shown to bind the greatest amount of tritiated peptide administered intravenously. In the 5- and 30-minute experiments angiotensin inhibited uptake of either metaraminol or norepinephrine in most tissues, especially at the higher dose levels, with the exception of the adrenal gland where uptake was increased. After the two-hour infusion inhibition of uptake was seen in most organs. When high titer angiotensin II antibodies were administered intravenously, responses to iv angiotensin were abolished. At this stage the uptake of tritiated norepinephrine was increased in kidney, heart, spleen, and vas deferens, while it was decreased in the adrenal gland. To see whether these biochemical findings are related to a physiological role, contractile responses of isolated perfused arteries of rabbits were studied. Angiotensin potentiated the increase in perfusion pressure after the infusion of norepinephrine, while angiotensin II antibodies decreased this response. Thus, it is concluded that angiotensin can modify the uptake and, hence, the inactivation of the sympathetic neurotransmitter and possibly by this mechanism alter the physiological response to norepinephrine and sympathetic stimulation.
Does the Severity of the Early Perfusion Deficit in Ischemic Stroke Predict the Fate of The PWI/DWI Mismatch?
Authors: Thijs Vincent N , Neumann-Haefelin Tobias , Moseley Michael E , Marks Michael P , Albers Gregory W
Published: March 2022

9

The degree of expansion of the early DWI lesion into the volume of the baseline PWI lesion is variable. In some patients partial recruitment of the DWI lesion volume occurs, while other patients develop a DWI lesion that equals or exceeds the size of the initial PWI volume. We investigated whether a quantitative analysis of the severity of the early perfusion deficit predicted the evolution of the PWI/DWI mismatch. Methods We studied patients with acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset and after 4–5 days. Maps of CBF, CBV and Mean Transit Time(MTT)were created after deconvolution of the arterial input function with the time-concentration curve. We compared the lesion volume on DWI at f/u with the baseline MTT volume. Patients in whom the lesion volume on DWI at f/u was smaller than the initial PWI deficit (group 1) were compared with patients in whom the DWI lesion at f/u (group 2) was ≥ than the initial PWI volume. Characteristics analysed included age, NIHSS, time to MRI, initial DWI volume, initial PWI volume, absolute mismatch volume, relative MTT(rMTT), CBF(rCBF) and CBV (rCBV) of the baseline PWI. Results Thirteen patients had an initial PWI>DWI mismatch of >20%. Seven of these patients (group 1) had DWI lesions at f/u that were smaller than the initial PWI lesion (mean 55% of PWI volume), while in 4 patients (group 2) the f/u DWI volume was larger than the PWI volume (mean 121% of initial PWI volume). Only the median rMTT (2.7 [group 1] versus 5.2 [group 2], p=0.006) and the median rCBV (1.4 [group 1] versus 2.7 [group 2], p=0.006) differed between the two groups. The initial rMTT and rCBV correlated significantly with the degree of expansion of the DWI lesion (ρ= 0.918 for rMTT and 0.864 for rCBV, p<0.01). Two patients, who were excluded because of early reperfusion, had no substantial increase in the size of the initial DWI lesion despite severely increased rMTT and rCBV. Conclusion Among acute stroke patients with PWI>DWI, who do not have early reperfusion, the degree of expansion of the initial DWI lesion correlates with the severity of the initial perfusion deficit as measured by the rMTT and the rCBV.
A Diffusion-Perfusion MRI Signature Predicting Hemorrhagic Transformation Following Intra-Arterial Thrombolysis
Authors: Kidwell Chelsea S , Saver Jeffrey L , Mattiello James , Alger Jeffry R , Saver Jeffrey L , Starkman Sidney , Duckwiler Gary , Vespa Paul M , Jahan Reza , Liebeskind David S , Vinuela Fernando
Published: March 2022

12

Introduction:
Hemorrhagic transformation is a major limitation of thrombolytic therapy for the treatment of acute ischemic stroke. A method to identify patients at high risk for hemorrhage would be of substantial value for selecting the best candidates for treatment.
Methods:
Diffusion-perfusion MRIs were obtained prior to treatment and at 7 days post-treatment in patients with large vessel anterior circulation occlusions treated with intra-arterial (IA) thrombolysis. Patients received either combined IV/IA tPA or only IA thrombolytics (tPA or urokinase) within 6 hours of symptom onset. CT scans were performed immediately following the angiographic procedure and at 24 hours. Regions of hemorrhagic transformation were outlined on the post-treatment scans, which were then co-registered to the pretreatment MRI. A stepwise discriminant analysis was performed using pretreatment apparent diffusion coefficient (ADC) and mean transit time (MTT) measures to identify voxels that developed hemorrhage.
Results:
Eighteen patients were studied with mean age 73, 12 females / 5 males, median NIHSS score 14. Five patients (29%) developed regions of hemorrhagic transformation following therapy. There were no significant differences in time to pretreatment MRI or time to completion of thrombolysis between patients who developed hemorrhage vs. those that did not. For regions that developed hemorrhage, mean ADC was 583 um2/sec and mean MTT was 38 secs, vs. 746 and 25 for regions that went on to infarction, vs. 874 and 17 for regions that were salvaged (p<0.05 for all mean comparisons by ANOVA). A discriminant model employing pretreatment ADC and MTT variables correctly classified tissue fate (hemorrhage vs. non-hemorrhage) with overall accuracy 85%.
Conclusions:
In humans undergoing intra-arterial thrombolysis, pretreatment MRI ADC values are significantly lower and MTT values significantly higher in regions that develop hemorrhagic transformation compared to regions that are salvaged or develop ischemic infarction. Using these variables, a discriminant model can correctly classify tissue fate with overall accuracy of 85%.
Subgroup Analysis of Patients with Severe Acute Neurological Ischemic Syndromes without Diffusion Weighted Magnetic Resonance Imaging Abnormalities
Authors: Szabo Kristina , Behrens Stephan , Hirsch Jochen , Hennerici Michael
Published: March 2022

14

Several magnetic resonance imaging (MRI) studies have reported correlations of the acute neurological deficit (NIHSS) and lesion size on early diffusion weighted (DWI). The majority of patients falls into this category but as exceptions from the rule patients may present with no or only very small DWI lesions but severe neurological deficits. We analysed serial MRI in this potentially important subgroup of acute ischemic syndromes.
Methods:
MRI was performed on a 1.5T Siemens Vision unit including T
2
-, T
1
-weighted, MR-angiography, echo-planar DWI and perfusion(T
2*
+ Gadolinium injection)- weighted MRI (PWI). Early (8≤hours) and follow-up (at 48–72hours) MRI was analysed in 13 patients with severe acute ischemic neurological syndromes (NIHSS≥8). In all patients there was no or only minimal abnormality on early isotropic DWI (
b
=1000mm
2
/sec, ADC maps)and evidence of hemodynamic compromise (MCA main stem, MCA branch, PCA, PICA) on TTP maps and a corresponding lack of flow signal on MRA.
Results:
Follow-up MRI determined 2 patient subgroups: 1. In 6 patients in whom MRI was performed within 90 minutes after symptom onset the complete DWI lesion had developed only on the follow-up MRI. Those patients showed no or only slight clinical improvement. 2. In 7 patients there was no or only a small DWI lesion on follow-up MRI while there was clinical improvement. In 5/7 patients TTP maps showed resolution or marked improvement of the PWI abnormality on follow-up.
Conclusions:
Two settings may cause early unrevealing DWI: 1. On early MRI performed within 90 minutes after symptom onset a DWI lesion may not have developed and the extent of an ischemic lesion may be underestimated. 2. The hemodynamic compromise may be less severe (comparable to the concept of the penumbra) causing neurological symptoms without the development of complete tissue infarction.
Incidence Rates of Stroke for Blacks and Whites: Preliminary Results from the Greater Cincinnati/Northern Kentucky Stroke Study
Authors: Broderick Joseph P , Miller Rosie , Khoury Jane C , Alwell Kathleen , Kissela Brett M , Woo Daniel , Shukla Rakesh , Moomaw Charlie , Gebel James , Pancioli Arthur M , Brott Thomas G , Kothari Rashmi U
Published: March 2022

24

Background:
We have previously estimated the stroke incidence rate in the US to be 731,000/yr using data from blacks in Cincinnati and whites in Rochester, MN. We present preliminary stroke incidence rates using data from white and black residents of the Greater Cincinnati metropolitan area.
Methods:
All strokes between 1/1/93–6/30/94 for blacks and 7/1/93–6/30/94 for whites were identified by surveillance of ICD-9 discharge codes from hospitals (430–438, 1
o
or 2
o
), coroner’s records, and surveillance of outpatient settings including emergency departments, hospital based outpatient clinics, family practice centers, and a random sampling of primary care offices and nursing homes. More than 17,000 potential stroke/TIA events were screened. During abstraction, research nurses determined stroke subtype, using strict criteria. Overall agreement on stroke subtype and diagnosis between study nurses and physicians is 87% (κ = 0.71). The incidence rates per 100,000 for stroke were calculated and standardized to the 1990 total U.S. population.
Results:
Rates of first-ever stroke among blacks were consistently higher than rates for whites for all stroke subtypes (Table). The overall rate of first-ever and recurrent stroke was 291 per 100,000.
Conclusion:
Based on these incidence rates, derived from a large, population-based study, we estimate that 760,000 strokes will occur in the US in the year 2000.
Modelling Feasibility of Genetic Approaches to Human Stroke
Authors: Hassan Ahamad , Sham Pak , Markus Hugh
Published: March 2022

33

Background
Twin, population and animal studies suggest that genetic factors are important in stroke. To date all research in humans has used case control (CC) methods to determine association between candidate genes and stroke. Alternative approaches include linkage analysis with the advantage of allowing detection of novel genes and transmission disequilibrium testing, which uses internal family controls e.g.parents(TDT) or unaffected sibs (S-TDT)to reduce the risk of population stratification which is a problem in case control studies. Despite theoretical benefits, the feasiblity of these methods remains unknown.
Methods
Family history was prospectively determined in 727 consecutive cerebrovascular patients and 623 age matched controls. Patients with suspected Mendelian syndromes were excluded. Parent and sibling status (alive or dead and the presence of stroke)was documented. The data was used to model the number of stroke patients required for the different study designs.
Results
Family history of young stroke (≤65)was an independent risk factor for ischaemic stroke OR 1.45 (95% CI 1.01–2.09) p=0.05, early onset proband stroke (≤65) OR 2.22(1.42–3.50)p=0.0005 and stroke due to large vessel disease OR 1.75 (1.09–2.83) p=0.02. In the age group <65 (n=305), 14 affected sibs, 19 parent offspring trios and 626 discordant sibling pairs were identified. The adjusted sibling relative risk ratio was estimated to be 1.78. If 3 genetic loci play an important role in stroke, this translates into 1000 affected sibling pairs being required for an affected sib pair linkage study. Over 100 000 patients would require screening based on a 50% recruitment rate in relatives. For candidate gene studies, assuming an odds ratio of 2 and allele frequency of 0.1, 986 (CC),31681 (TDT) and 3635 (S-TDT) patients would need to be screened to achieve the necessary sample sizes.
Conclusion
This study supports the role of independent genetic risk factors in stroke which have greater influence in young individuals. Novel approaches are potentially feasible, although linkage studies and TDT would require large scale multicentre collaborations.
Risk Factors for Misdiagnosis of Subarachnoid and Intracerebral Hemorrhage
Authors: Oen-Hsiao Joyce M , Kernan Walter N , Viscoli Catherine M , Brass Lawrence M , Morgenstern Lewis B , Awad Issam A , Wilterdink Janet L , Feldmann Edward , Brott Thomas , Horwitz Ralph
Published: March 2022

35

Objectives.
To identify risk factors for misdiagnosis of brain hemorrhage in younger patients. Methods. We performed a nested case-control study among 702 subjects from the Hemorrhagic Stroke Project (HSP). The HSP enrolled men and women ages 18–49 years hospitalized during 1994–1999 for a subarachnoid (SAH) or intracerebral (ICH) hemorrhage in 4 U.S. regions. Case subjects were HSP patients who did not receive an appropriate diagnostic evaluation within 24 hours of consulting a physician. Appropriate evaluation was recognized when a brain CT scan and (if CT negative) LP were completed within 24 hours. For each case, two correctly-diagnosed control subjects were matched on recruitment site and period. We calculated odds ratios (ORs) for the association between risk factors and misdiagnosis. Results. The case group comprised all 54 HSP subjects (7.7%)with a misdiagnosis, including 24 (45%) with ICH and 30 (55%) with SAH. The control group comprised 108 subjects, all successfully matched. Six features were significantly associated with risk for misdiagnosis (95% CI excludes 1): initial evaluation in a physician’s office or by telephone (vs. hospital), OR=18.31 [95% CI=6.86, 48.84], absence of alarm symptoms (photophobia, LOC, focal weakness), OR=5.29 [2.61, 10.74], presence of headache, OR= 5.11 [1.14, 22.95], no history of hypertension, OR=2.05 [1.02, 4.11], college education, OR=1.99 [1.02, 3.89], age < 40, OR=1.99 [1.01, 3.92]. Three other features approached significance: no effortful activity at onset, OR=2.96 [0.82, 10.66], Hispanic ethnicity, OR=2.17 [0.77, 6.15], and absent neck pain, OR=1.65 [0.84, 3.24]. In logistic regression analysis including all 6 significant features, location of initial evaluation and absence of alarm symptoms remained associated with risk for misdiagnosis (p<.05).
Conclusion.
Physicians are most likely to misdiagnose brain hemorrhage in patients without alarm symptoms who are seen outside a hospital emergency room. Low stroke risk (no hypertension, young age) may be additional risk factors. Efforts to reduce misdiagnosis should be directed at primary care physicians who see low-risk patients with milder symptoms.
Intravenous TPA for Ischemic Stroke Patients: Houston Experience 1996–2000
Authors: Grotta James C , Alexandrov Andrei V , Burgin W Scott , Long Megan , El-Mitwalli Ashraf , Campbell Morgan , Morgenstern Lewis B , Malkoff Marc
Published: March 2022

40

Background:
Implementation of intravenous (IV) tissue plasminogen activator (TPA) therapy with the NINDS protocol has been reported with variable safety. Our center has an experienced stroke team of fellows and stroke faculty servicing one University hospital and three community hospitals.
Methods:
We report our experience in the treatment of 269 consecutive patients with ischemic stroke within the first 3 hours after symptom onset with 0.9 mg/kg IV TPA according to the NINDS protocol.
Results:
A total of 269 patients were treated between 1/96 and 6/00: median age 69 (range 24–93 years, females 48%). Pre-treatment NIHSS was 14±6 (median 14, range 4–33 points). TPA bolus was given at 137 min (range 30–180 minutes) with 28% of patients treated within 2 hours. Median door-to-needle time was 68 minutes (range 10–129 minutes). Overall symptomatic ICH rate was 4.5% (range 2.6% - 8.7% between hospitals, ns), with a decline noted from 1996 to 2000 (Table). Protocol violations (excessive blood pressure, seizure at onset) were found in 13% of all patients and symptomatic ICH rate in these patients was 15%. At 24 hours NIHSS score was 9±8 (median 8, range 0–36 points). In hospital mortality was 15% and discharge NIHSS score was 6±7 (median 3, range 0–36). Long-term follow-up will be reported.
Conclusions:
Intravenous TPA in a dose of 0.9 mg/kg can be given with a risk of symptomatic ICH lower than previously reported. Safety of TPA improved from 1996 to 2000. We conclude that the safety of TPA therapy depends more on the expertise of the treating team than the type of the hospital.
Seeking Help When Strokes Happen: A Study of 911 Tapes
Authors: Rosamond Wayne D , Morris Dexter L , Evenson Kelly R , Brice Jane H , Schroeder Emily B
Published: March 2022

43

Recommendations from the American Stroke Association stress the importance of treating stroke symptoms as medical emergencies and encourages the public to call 911 if they witness or experience a stroke. However, many patients experience delays from onset of symptoms to hospital arrival of 4 to 6 hours. Use of emergency medical service (EMS) is an important link in the chain of recovery. To investigate EMS use, tapes of calls to 911 were evaluated for 93 confirmed stroke cases arriving at the hospital by ambulance in 2 North Carolina counties during 1999. Tapes were transcribed and linked to EMS trip sheets. Seventy-two percent of patients were women, 30% were black, and their mean age was 76 years. Forty-three percent of the calls were placed by medical personnel and 37% by a family member. Only 5 of the 93 calls were made by the patient. In 42 (45%) of calls, the term “stroke” or “cerebrovascular accident” was recorded. In most instances (35 of 42) the term was first used by the caller. A decreased ability to walk or altered mental status were the two most frequently reported symptoms (30% each), followed by breathing difficulty (27%), impaired speech (25%), and muscle weakness (16%). In 78% of the calls, dispatchers sent EMS personnel to the scene at highest priority, with lights and sirens. The median time from dispatch to arrival of EMS personnel on the scene was 7 minutes. The median elapsed time from receiving the 911 call to the patient’s arrival at the hospital was 42 minutes. This study suggests that most 911 calls in these two counties were dispatched with highest priority. While EMS arrived in 7 minutes, it took more than one-half hour from arrival at the scene to reach the hospital. Few calls to 911 were made by the patients themselves. The information from this study will be useful in designing public health strategies to reduce prehospital delay for stroke patients.
Validity and Reliability of the Thrombolysis in Brain Infarction (TIBI) Flow Grades
Authors: Burgin W Scott , Wojner Anne W , Demchuk Andrew M , Felberg Robert A , Barber Philip A , Hill Michael D , Malkoff Marc , El-Mitwalli Ashraf , Piriyawat Paisith , Newcommmon Nancy , Button Allison
Published: March 2022

48

Background:
In patients eligible for thrombolytic therapy, the TIBI grading system defines residual transcranial Doppler (TCD) flow signals at the site of clot location. In addition, TIBI flow grades correlate with angiography and predict short-term improvement following TPA therapy. The aim of this study was to develop a valid and reliable instrument to assess how accurately health professionals determine TIBI flow grades.
Methods:
Two expert sonographers developed a 60 question computerized examination of the 6 TIBI flow grades. Gold standard interpretation was determined by a consensus interpretation by a pool of expert sonographers. All items were equally weighted and written in a standard format. A computerized TIBI grading tutorial and standard interpretation rules were available for all test-takers. To assess content validity and reliability, a blinded panel of 3 experts independently took the examination. Inter-rater agreement was determined among experienced sonographers, stroke neurologists, and other health professionals (N=11).
Results:
Expert assessment of each test item measured objective congruence at 1.0, overall test validity coefficient of 0.996 (95%CI 0.993–0.997), and an item/TIBI flow grade validity coefficient of 0.992 (95%CI 0.996–0.997). Overall test and individual item reliability had coefficients of 0.98(95%CI 0.97–0.99) and 0.97 (95%CI 0.95–0.98, p<0.0001) respectively. Inter-rater agreement was 0.89 (coefficient of contingency) and 0.86 (kappa) for all participants. Kappa range included 0.98 for an experienced interpreter, 0.81–0.89 for stroke neurologists with beginner experience in TCD and 0.65 for those without previous TCD experience (66% of correct answers after 1 hour tutorial).
Conclusions:
Our computerized examination is a valid and reliable tool to assess an individuals ability to score TIBI flow grades. In addition, TIBI flow grade evaluation has a high degree of inter-rater reliability, even among those with limited experience in ultrasound.
A comparison of CT versus MR imaging in acute stroke using ASPECTS: Will the “new” replace the “old” as the preferred imaging modality?
Authors: Barber Philip A , Demchuk Andrew M , Hill Michael D , Pexman Warwick , Hudon Mark E , Tomanek Anna , Beaupre Derek , Frayne Richard , Buchan Alastair M
Published: March 2022

49

Background:
CT is considered less sensitive and reliable than MRI for the detection of ischemia in hyperacute stroke. This study compares these two modalities.
Methods:
We included all ischemic stroke patients who had both CT < 6 hours and MRI < 7 hours from onset. A quantitative scoring system (ASPECTS) was applied to CT, MR FLAIR and DWI at baseline and at follow-up (<36h) by five independent observers (2 neuroradiologists and 3 stroke neurologists) with only knowledge of stroke symptom side. CT was also assessed for hyperdense MCA and sylvian fissure MCA “dot” signs. The analysis was derived from consensus agreement among individual observers. MRA was the “gold standard” for vascular occlusion.
Results:
52 patients had CT and MRI acutely. The median NIHSS was 9. The mean onset to CT was 125 minutes and to MRI 241 minutes (P< 0.001). Baseline CT and DWI ASPECTS were highly correlated (r 0.75 P<0.001). Median baseline CT, FLAIR and DWI scores using ASPECTS were 9, 10, and 8.5 respectively. At baseline DWI ASPECTS was 0.5 points lower than CT, but CT ASPECTS was a significant 1 point lower than FLAIR (P<0.03 and <0.001 respectively, Wilcoxon signed rank). However there was no difference between baseline CT and DWI at predicting follow-up DWI ASPECTS (P=0.12 Wilcoxon signed rank). Intraclass correlation coefficients to assess agreement among observer scores at baseline were moderate to excellent for CT and DWI (0.72 95% CI 0.62–0.81 and 0.71 95% CI 0.62–0.81 respectively) but was poor for FLAIR (0.43 95% CI 0.29–0.57). Hyperdense MCA and MCA “dot” signs had sensitivity 0.57 and specificity 0.96, using MRA as the “gold standard” for MCA occlusion (χ
2
P<0.001). Interobserver agreement for hyperdense signs was in the moderate to good range (kappa 0.50–0.67).
Conclusion:
CT appears as good as DWI for assessing ischemic tissue in hyperacute stroke when evaluated by experienced CT readers using ASPECTS. We speculate this surprising finding could be explained by excessive DWI basal ganglia hypointensity, MR susceptibility artifact at skull base, and less conspicuous DWI abnormality than previously recognised in the first hours of ischemia.
Neural progenitor cells proliferate and differentiate when transplanted into ischemic brain or retina.
Authors: Gupta Gaurav , Gokhan Solen , Singh Manjeet , Cohen Bella , Rosenbaum Pearl S , Ocava Leonore C , Kessler John A , Mehler Mark F , Rosenbaum Daniel M
Published: March 2022

57

The adult mammalian brain contains neural stem and progenitor cells (NPCs) that can proliferate, self-renew, and generate all of the cellular elements of the mature brain, including neurons. The ability of NPCs to respond
in vivo
to injury-induced signals that can direct their differentiation towards multiple distinct neural lineages suggest that these undifferentiated progenitors offer a dynamic and versatile source of cells for neural regeneration following CNS injury. The purpose of this study was to determine if NPCs obtained from rat embryonic cortex would proliferate and differentiate into mature neurons and glia when transplanted
in vivo
into rat brain or retina subjected to ischemia. Primary undifferentiated progenitor cell clones from embryonic day 14.5 rat cortex were labeled with the cell membrane marker, PKH-26. Donor cells were transplanted into the cerebral cortex (CC), subventricular zone (SVZ) and vitreous cavity (VC) of the eye. In the ischemic animals as well as the control animals, some of the donor cells proliferated and differentiated into oligodendrocytes (CNPase) and astrocytes (GFAP) as early as 7 days following transplantation. By contrast, by 21 increasing to 45 days, most donor cells in CC and SVZ exhibited a neuronal phenotype (NeuN, MAP-2). However, transplantation into the SVZ was highly effective in generating new neurons in ischemic brain whereas direct transplantation into post-ischemic cortex was significantly less effective. Interestingly, donor cells transplanted in VC acquired a neuronal phenotype compatible with those seen in CC. Our data suggest the exogenous NPCs can differentiate into neurons and glia and that local environmental factors differentially regulate the profile of progenitor cell regenerative responses to CNS injury.
Rapid Nuclear Factor κB Activation and Cytokine and Heme Oxygenase-1 Gene Expression in Edematous White Matter After Porcine Intracerebral Hemorrhage
Authors: Wagner Kenneth R , Knight James , Packard Benjamin A , M de Courten-Myers Gabrielle , Smulian Alan G , Broderick Joseph P
Published: March 2022

63

Introduction:
Lobar intracerebral hemorrhage (ICH) induces secondary events in perihematomal white matter including oxidative stress, edema and demyelination. Pro-inflammatory cytokines may play a role, since tumor necrosis factor-α (TNF-α)and interleukin-1β (IL-1β) induce vasogenic edema and TNF-α induces apoptosis in oligodendrocytes. Also, inhibition of heme oxygenase-1 (HO-1) reduces ICH-induced edema (Wagner et al. 2000). Since the oxidatively sensitive transcription factor, nuclear factor κB(NF-κB), regulates these genes, we hypothesize that NF-κB is activated and these mRNAs are expressed in perihematomal white matter early after ICH.
Methods:
We infused 2.5 ml of autologous blood into the frontal white matter of pentobarbital anesthetized pigs (N=12)and monitored and controlled physiologic variables. We froze brains
in situ
between 0.5 and 24 hrs post-ICH. We sampled tissue from perihematomal edematous and similarly located control white matter. Nuclear proteins were extracted for Western blotting (NF-κBp65 subunit) and for electrophoretic mobility shift assays (EMSA) and total RNA was extracted for RT-PCR. We used porcine-specific TNF-α, IL-1β, HO-1 and β-actin primers. Relative changes in densitometric data were normalized to β-actin.
Results:
NF-κB was activated at 30 min in edematous white matter and remained elevated during the 24 hrs following ICH. NF-κBp65 subunit levels were increased to 160±9% of control (mean±SD, N=3)in nuclear extracts between 0.5 and 2 hrs. A further significant (p<0.01) increase to 233±26% (N=3) occurred between 4 and 24 hrs. Including an inhibitor of NF-κB translocation in the infused blood prevented NF-κBp65 appearance in nuclear extracts. Increased NF-κB DNA binding activity (EMSA)was present at 2 hrs. Expression of TNF-α, IL-1β and HO-1 mRNAs were significantly (p<0.05) upregulated at 2 hrs (N=6) to 640±257%, 649±248% and 236±39% of control, respectively.
Conclusion:
Early NF-κB activation and cytokine and HO-1 gene expression may underlie delayed edema, DNA fragmentation and demyelination in perihematomal white matter after ICH.