bluuebunny/crossref_metadata_2025 huggingface dataset:
Underlying Cause of Death in Demented and Non-Demented Elderly Canadians
Authors: Chamandy Nicholas , Wolfson Christina
Published: June 2005

This paper examines the associations between clinical dementia and underlying cause of death (UCD) in a population-based sample of seniors who took part in the Canadian Study of Health and Aging (CSHA). Cause-of-death data were obtained via death certificates for 2,924 of 2,982 deceased subjects. Among the decedents were 823 clinically demented and 670 clinically non-demented participants. Using logistic regression we examined factors associated with a particular UCD in the overall group and also in the subgroup of demented seniors. Dementia was found to be associated with an increased risk of death from pneumonia. Both Alzheimer’s disease and vascular dementia appear to decrease the risk of mortality from neoplasm. To our knowledge, this study is the first of its kind that combines a large, representative sample with thorough clinical assessment of cognitive status.
The C3435T Polymorphism of MDR1 and Susceptibility to Adult Glioma
Authors: Miller Katie L. , Kelsey Karl T. , Wiencke John K. , Moghadassi Michelle , Miike Rei , Liu Mei , Wrensch Margaret
Published: June 2005

Introduction: The multidrug resistance-1 (MDR1) gene encodes a pump that prevents potentially carcinogenic substances from crossing the blood-brain barrier. We compare adult glioma cases and controls for the C3435T polymorphism that has been associated with reduced MDR1 expression. Methods: Adult glioma in the San Francisco Bay area and population-based controls were identified between 1991–1994 and 1997–1999. Genotyped cases (n = 458) and controls (n = 528) were compared using logistic regression controlling for age, gender and ethnicity, with later stratification by ethnicity, gender and histology. Results: With CC as the referent, the TT genotype was nonsignificantly less frequent among cases compared to controls (OR, 0.87; 95% CI: 0.6, 1.2). After stratification, only male glioblastoma was associated with TT genotype (OR, 0.51; 95% CI: 0.3, 1.0). Conclusions: Although the C3435T polymorphism does not appear to be associated with other types of glioma, we cannot rule out that this MDR1 polymorphism may be associated with glioblastoma among men.
Assessing Genetically Modified Crops to Minimize the Risk of Increased Food Allergy: A Review
Authors: Goodman Richard E. , Hefle Susan L. , Taylor Steven L. , van Ree Ronald
Published: June 2005

The first genetically modified (GM) crops approved for food use (tomato and soybean) were evaluated for safety by the United States Food and Drug Administration prior to commercial production. Among other factors, those products and all additional GM crops that have been grown commercially have been evaluated for potential increases in allergenic properties using methods that are consistent with the current understanding of food allergens and knowledge regarding the prediction of allergenic activity. Although there have been refinements, the key aspects of the evaluation have not changed. The allergenic properties of the gene donor and the host (recipient) organisms are considered in determining the appropriate testing strategy. The amino acid sequence of the encoded protein is compared to all known allergens to determine whether the protein is a known allergen or is sufficiently similar to any known allergen to indicate an increased probability of allergic cross-reactivity. Stability of the protein in the presence of acid with the stomach protease pepsin is tested as a risk factor for food allergenicity. In vitro or in vivo human IgE binding are tested when appropriate, if the gene donor is an allergen or the sequence of the protein is similar to an allergen. Serum donors and skin test subjects are selected based on their proven allergic responses to the gene donor or to material containing the allergen that was matched in sequence. While some scientists and regulators have suggested using animal models, performing broadly targeted serum IgE testing or extensive pre- or post-market clinical tests, current evidence does not support these tests as being predictive or practical. Based on the evidence to date, the current assessment process has worked well to prevent the unintended introduction of allergens in commercial GM crops.
Sublingual Immunotherapy for Allergic Rhinoconjunctivitis – The Seeming and the Real
Authors: Reider Norbert
Published: June 2005

Background: Subcutaneous specific immunotherapy (SIT) has been shown to be a causal treatment with long-term efficacy for allergic rhinoconjunctivitis and asthma, and a preventive measure against the development of asthma and new sensitizations. As it is associated with several inconveniences and serious side effects, sublingual immunotherapy (SLIT) has been developed to evade these problems. Methods: The present review of previously published studies on allergic rhinoconjunctivitis aimed to determine the efficacy of SLIT in comparison with subcutaneous treatment and to summarize long-term results of immunotherapy and its effects on the prevention and treatment of asthma and the prevention of new sensitizations. Results: The effect of SLIT on allergic rhinoconjunctivitis is low to moderate, depends on the allergen used and is more pronounced in adults than in children, in whom a consistent effect has not been demonstrated. Direct comparison with SIT shows conflicting and inconsistent results. Detailed studies on the prevention of asthma and new sensitizations are not available. Consistent effects of asthma treatment on both symptom and medication scores and lung function have not been reported. A quantitative evaluation is not possible due to indistinct inclusion criteria and different outcome criteria. In summary, currently SLIT plays no significant role in the treatment of asthma, apart from children monosensitized to house dust mites in whom it may have low-moderate effects. Only one study deals with the long-term efficacy of SLIT, which demonstrated a persistent positive effect on asthma, whereas data on rhinoconjunctivitis are completely lacking. Conclusions: Primary and secondary targets of specific immunotherapy have not been answered satisfactorily for the sublingual route. To date, SLIT cannot be recommended as an adequate alternative to the subcutaneous form. Questions regarding the cumulative dose, duration of therapy and immunological mechanisms have also not been answered. The indication should thus be limited to adult patients with pollen-induced rhinoconjunctivitis being unable to perform SIT, e.g. due to significant side effects.
Regulatory T Cells Induced by Ultraviolet Radiation
Authors: Schwarz Thomas
Published: June 2005

Regulatory T cells belong to a subset of T lymphocytes which suppress immune reactions in an antigen-specific fashion. They play an important role in the prevention of autoimmune diseases. Ultraviolet (UV) radiation was also found to suppress the immune system in an antigen-specific fashion mediated by UV-induced regulatory T cells. Induction of these cells by UV radiation is an active process which requires antigen presentation by UV-damaged but still viable Langerhans cells in the lymph nodes. UV-induced regulatory T cells have been recently characterized to express CD4 and CD25 and to release the immunosuppressive cytokine interleukin-10 upon activation. Once activated in an antigen-specific fashion, they suppress immune responses in a general fashion via the release of interleukin-10, a phenomenon called bystander suppression. Upon intravenous injection, UV-induced regulatory T cells primarily migrate into the lymph nodes, explaining why they preferentially suppress sensitization. Recently, the development of regulatory T cells was demonstrated in an experimental model of photopheresis, a therapeutic regimen which is used for the therapy of autoimmune diseases, transplant rejection and graft-versus-host disease. Further characterization of these cells will determine whether they can be applied therapeutically in the future with the ultimate aim to induce specific immunosuppression.
Recombinant Der p 1 and Der f 1 with in vitro Enzymatic Activity to Cleave Human CD23, CD25 and α1-Antitrypsin, and in vivo IgE-Eliciting Activity in Mice
Authors: Takai Toshiro , Kato Takeshi , Ota Mikiko , Yasueda Hiroshi , Kuhara Takatoshi , Okumura Ko , Ogawa Hideoki
Published: June 2005

Background: The major house dust mite group 1 allergens Der p 1 and Der f 1 are the most potent indoor allergens. Der p 1 cleaves human cell surface molecules, the low-affinity IgE receptor (CD23/FcΕRII), the α-subunit of the IL-2 receptor (CD25), and a protease inhibitor α1-antitrypsin, and in vitro and in vivo studies suggested the importance of its proteolytic activity in the pathogenesis of allergy. Recently, we established an efficient system to prepare correctly folded active recombinant Der p 1 and Der f 1 (Der p 1-N52Q and Der f 1-N53Q) with similar molecular sizes, secondary structures and allergenicities as their natural types. To evaluate whether Der p 1-N52Q and Der f 1-N53Q are suitable for use in future in vitro and in vivo studies as alternatives to the natural types, we investigate their proteolytic activity to cleave the human proteins and IgE-eliciting activity in mice. Methods: Proteolytic activities of Der p 1-N52Q and Der f 1-N53Q against a short peptide substrate, a collagen substrate Azocoll, human CD23 and CD25 expressed on the cells and human α1-antitrypsin were analyzed by kinetic assays for proteolysis of the fluorogenic or colorimetric substrates, flow cytometry and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively. Mice were intraperitoneally immunized with Der p 1-N52Q and Der f 1-N53Q adsorbed on Alum, and the serum IgE levels were measured by sandwich ELISA. Results: Der p 1-N52Q and Der f 1-N53Q showed proteolytic specificities against the short peptide substrate, Azocoll, human cell surface CD23 and CD25 and human α1-antitrypsin, and elicited significant serum IgE levels in immunized mice. Conclusion: The recombinant forms, Der p 1-N52Q and Der f 1-N53Q, will be useful tools as alternatives to the natural Der p 1 and Der f 1 for various in vitro and in vivo analyses.
Lipid Transfer Proteins and Allergy to Oranges
Authors: Ahrazem Oussama , Ibáñez M. Dolores , López-Torrejón Gema , Sánchez-Monge Rosa , Sastre Joaquin , Lombardero Manuel , Barber Domingo , Salcedo Gabriel
Published: June 2005

Background: Lipid transfer proteins (LTPs) are relevant fruit allergens, recently proposed as model plant food allergens. No citrus fruit allergen has been characterized to date. We sought to identify and isolate citrus fruit LTPs and to explore their relevance in orange allergy. Methods: Twenty-seven patients, showing mainly oral allergy syndrome after orange ingestion, as well as positive prick responses and serum-specific IgE levels to orange, were selected. Natural orange and lemon LTPs, as well as a recombinant orange LTP isoform expressed in Pichia pastoris, were isolated by chromatographic methods and characterized by N-terminal amino acid sequencing and matrix-assisted laser desorption/ionizaion mass spectrometry, and DNA sequencing of the corresponding cDNA in the case of the recombinant allergen. Specific IgE determination, immunodetection, ELISA-inhibition assays and in vivo skin prick tests (SPTs) were performed with all three purified allergens and with the major peach LTP allergen, Pru p 3. Results: The natural allergens purified from orange (nCit s 3) and lemon (nCit l 3) showed very similar N-terminal amino acid sequences (18 out of 20 identical residues), typical of LTPs, and molecular masses of 9,610 and 9,618 Da, respectively. The recombinant orange isoform (rCit s 3) expressed in P. pastoris (16 out of 20 residues identical to its natural counterpart in the N-terminal region) presented 92 amino acid residues and 9,463 Da, and 67% sequence identity with rPru p 3. Of the 27 sera analyzed, specific IgE to the purified allergens was found in 54% for nCit l 3, 48% for nCit s 3, 46% for rCit s 3 and 37% for rPru p 3. Positive SPT responses were obtained in 7 out of 26 patients tested for nCit s 3, 3 out of 8 for nCit l 3 and 10 out of 26 for nPru p 3. ELISA-inhibition assays showed an equivalent IgE-binding pattern for the natural and recombinant orange LTPs, and IgE cross-reactivity among the purified orange, lemon and peach LTP allergens. Conclusions: Members of the LTP allergen family are involved in allergy to oranges, displaying positive in vitro and in vivo reactions in 30–50% of the patients studied. Both orange and lemon allergens show cross-reactivity with the major peach allergen Pru p 3.
Effects of Interferon-β1a on the Hypothalamic-Pituitary-Adrenal Axis, Leukocyte Distribution and Mood States in Multiple Sclerosis Patients
Authors: Goebel Marion U. , Czolbe Frank , Becker Holger , Janssen Onno E. , Schedlowski Manfred , Limmroth Volker
Published: June 2005

Acute interferon-β (IFN-β) administration transiently activates the hypothalamic-pituitary-adrenal (HPA) axis, increases granulocytes, and reduces lymphocytes in peripheral blood. To test whether these effects are still present after long-term treatment, 13 patients with relapsing-remitting multiple sclerosis were analyzed at baseline, and 1, 2, 4, and 8 h after IFN-β1a injection at two occasions: at the initial administration and after 1 year of continuous treatment. Long-term treatment reduced the responsiveness of the HPA axis to the injection, and abolished the distributional changes in leukocyte numbers. One-year treatment with IFN-β1a did not induce mood alterations as assessed by the Profile of Mood States. These results suggest that long-term IFN-β therapy has a profound impact on leukocyte distribution and the neuroendocrine response to the drug.
Type 2 Diabetic Mice Have Increased Arteriolar Tone and Blood Pressure
Authors: Bagi Zsolt , Erdei Nora , Toth Attila , Li Wei , Hintze Thomas H. , Koller Akos , Kaley Gabor
Published: June 2005

Objective—

Type 2 diabetes mellitus (T2-DM) is frequently associated with vascular dysfunction and elevated blood pressure, yet the underlying mechanisms are not completely understood. We hypothesized that in T2-DM, the regulation of peripheral vascular resistance is altered because of changes in local vasomotor mechanisms.

Methods and Results—

In mice with T2-DM (C57BL/KsJ-db
−
/db
−
), systolic and mean arterial pressures measured by the tail cuff method were significantly elevated compared with those of control (db
+
/db
−
) animals (db/db, 146±5 and 106±2 mm Hg versus control, 133±4 and 98±4 mm Hg, respectively;
P
<0.05). Total peripheral resistance, calculated from cardiac output values (measured by echocardiography) and mean arterial pressure were significantly elevated in db/db mice (db/db, 25±6 versus control, 15±1 mm Hg[middot]mL
−1
[middot]min
−1
). In isolated, pressurized gracilis muscle arterioles (diameter ≈80 μm) from db/db mice, stepwise increases in intraluminal pressure (from 20 to 120 mm Hg) elicited a greater reduction in diameter than in control vessels at each pressure step (at 80 mm Hg, db/db, 66±4% versus control, 79±3%). The passive diameters of arterioles (obtained in Ca
2+
-free solution) and the calculated myogenic index were not significantly different in the 2 groups. The presence of the prostaglandin H
2
/thromboxane A
2
receptor antagonist SQ29548 did not affect arteriolar diameters of control mice but reduced the enhanced arteriolar tone of db/db mice back to control levels (at 80 mm Hg, 80±4%). The inhibitor of cyclooxygenase-1 (COX-1), SC-560, did not affect the basal tone of arterioles, whereas NS-398, an inhibitor of COX-2, caused a significant shift in the arteriolar pressure–diameter curve of vessels from db/db mice (at 80 mm Hg, 76±3%) but not in those of control mice. Also, in aortas of db/db mice, expression of COX-2 was enhanced compared with controls.

Conclusions—

Collectively, these findings suggest that in mice with T2-DM, the basal tone of skeletal muscle arterioles is increased because of an enhanced COX-2–dependent production of constrictor prostaglandins. These alterations in microvascular prostaglandin synthesis may contribute to the increase in peripheral resistance and blood pressure in T2-DM.
Overproduction of VLDL
1
Driven by Hyperglycemia Is a Dominant Feature of Diabetic Dyslipidemia
Authors: Adiels Martin , Borén Jan , Caslake Muriel J. , Stewart Philip , Soro Aino , Westerbacka Jukka , Wennberg Bernt , Olofsson Sven-Olof , Packard Chris , Taskinen Marja-Riitta
Published: June 2005

Objective—

We sought to compare the synthesis and metabolism of VLDL
1
and VLDL
2
in patients with type 2 diabetes mellitus (DM2) and nondiabetic subjects.

Methods and Results—

We used a novel multicompartmental model to simultaneously determine the kinetics of apolipoprotein (apo) B and triglyceride (TG) in VLDL
1
and VLDL
2
after a bolus injection of [
2
H
3
]leucine and [
2
H
5
]glycerol and to follow the catabolism and transfer of the lipoprotein particles. Our results show that the overproduction of VLDL particles in DM2 is explained by enhanced secretion of VLDL
1
apoB and TG. Direct production of VLDL
2
apoB and TG was not influenced by diabetes per se. The production rates of VLDL
1
apoB and TG were closely related, as were the corresponding pool sizes. VLDL
1
and VLDL
2
compositions did not differ in subjects with DM2 and controls, and the TG to apoB ratio of newly synthesized particles was very similar in the 2 groups. Plasma glucose, insulin, and free fatty acids together explained 55% of the variation in VLDL
1
TG production rate.

Conclusion—

Insulin resistance and DM2 are associated with excess hepatic production of VLDL
1
particles similar in size and composition to those in nondiabetic subjects. We propose that hyperglycemia is the driving force that aggravates overproduction of VLDL
1
in DM2.
Recombinant Leptin Promotes Atherosclerosis and Thrombosis in Apolipoprotein E–Deficient Mice
Authors: Bodary Peter F. , Gu Shufang , Shen Yuechun , Hasty Alyssa H. , Buckler Joshua M. , Eitzman Daniel T.
Published: June 2005

Objective—

The direct role of leptin in vascular disease remains controversial. The objective of this study was to examine the effects of leptin treatment on atherosclerosis and thrombosis in atherosclerotic-prone mice.

Methods and Results—

Sixteen-week-old, male apolipoprotein E–deficient mice were treated with injections of recombinant leptin (125 μg per day IP; n=10) or vehicle (n=10) for 4 weeks. Leptin treatment resulted in reduced epididymal fat (352±30.7 versus 621±61.5 mg;
P
=0.005) and fasting insulin (0.57±0.25 versus 1.7±0.22 ng/mL;
P
=0.014). Despite these metabolic benefits, leptin treatment resulted in an increase in atherosclerosis (8.0±0.95% versus 5.4±0.59% lesion surface coverage;
P
<0.05). Leptin treatment also resulted in a shortened time to occlusive thrombosis after vascular injury (21±2.1 versus 34.6±5.4 minutes;
P
=0.045).

Conclusions—

These studies indicate that exogenous leptin promotes atherosclerosis and thrombosis and support the concept that elevations of leptin may increase the risk for cardiovascular disease.
Association of the −92C/G and 807C/T Polymorphisms of the α
2
Subunit Gene With Human Platelets α
2
β
1
Receptor Density
Authors: Ajzenberg Nadine , Berroeta Clarisse , Philip Ivan , Grandchamp Bernard , Ducellier Pierre , Huart Virginie , Verpillat Patrice , Guillin Marie-Claude , Benessiano Joelle
Published: June 2005

Objective—

Platelet adhesion to the subendothelial tissue via the collagen receptor α
2
β
1
is a crucial event in vascular biology. Although evidence has been provided that the number of platelets α
2
β
1
copies is genetically determined, the molecular change primary responsible has not been yet elucidated. The aim of our present study was to investigate the effect of combined polymorphisms within both regulatory (−52C/T and −92C/G) and coding regions (807C/T and 1648A/G) of the α
2
subunit gene on human platelets α
2
β
1
receptor density and/or susceptibility to coronary artery disease (CAD).

Methods and Results—

Among 254 cardiac surgery patients, no evidence was found for an association between the α
2
subunit gene polymorphisms and CAD. In contrast, in a subgroup of 113 patients, we observed a significant association between all polymorphisms except −52C/T and α
2
β
1
receptor level. Furthermore, when 3 groups of patients were defined according to the tertiles of platelets α
2
β
1
copies, the −92C/807T haplotype was more frequent in the group of patients with high α
2
β
1
receptor level.

Conclusion—

These results suggest that an individual effect of each polymorphism located either in the coding or promoter sequence of the α
2
gene may act in combination to modulate variations in platelets α
2
β
1
receptor density.
Mineral Volume and Morphology in Carotid Plaque Specimens Using High-Resolution MRI and CT
Authors: Wolf Ronald L. , Wehrli Suzanne L. , Popescu Andra M. , Woo John H. , Song Hee Kwon , Wright Alexander C. , Mohler Emile R. , Harding John D. , Zager Eric L. , Fairman Ronald M. , Golden Michael A. , Velazquez Omaida C. , Carpenter Jeffrey P. , Wehrli Felix W.
Published: June 2005

Objective—

High-resolution MRI methods have been used to evaluate carotid artery atherosclerotic plaque content. The purpose of this study was to assess the performance of high-resolution MRI in evaluation of the quantity and pattern of mineral deposition in carotid endarterectomy (CEA) specimens, with quantitative micro-CT as the gold standard.

Methods and Results—

High-resolution MRI and CT were compared in 20 CEA specimens. Linear regression comparing mineral volumes generated from CT (
V

CT

) and MRI (
V

MRI

) data demonstrated good correlation using simple thresholding (
V

MRI

=−0.01+0.98
V

CT

;
R
2
=0.90; threshold=4×noise) and k-means clustering methods (
V

MRI

=−0.005+1.38
V

CT

;
R
2
=0.93). Bone mineral density (BMD) and bone mineral content (BMC [mineral mass]) were calculated for CT data and BMC verified with ash weight. Patterns of mineralization like particles, granules, and sheets were more clearly depicted on CT.

Conclusions—

Mineral volumes generated from MRI or CT data were highly correlated. CT provided a more detailed depiction of mineralization patterns and provided BMD and BMC in addition to mineral volume. The extent of mineralization as well as the morphology may ultimately be useful in assessing plaque stability.
Conditional Knockout of Macrophage PPARγIncreases Atherosclerosis in C57BL/6 and Low-Density Lipoprotein Receptor–Deficient Mice
Authors: Babaev Vladimir R. , Yancey Patricia G. , Ryzhov Sergey V. , Kon Valentina , Breyer Matthew D. , Magnuson Mark A. , Fazio Sergio , Linton MacRae F.
Published: June 2005

Objective—

Peroxisome proliferator-activated receptor gamma (PPARγ) is highly expressed in macrophage-derived foam cells of atherosclerotic lesions, and its expression may have a dramatic impact on atherosclerosis.

Methods and Results—

To investigate the contribution of macrophage PPARγ expression on atherogenesis in vivo, we generated macrophage-specific PPARγ knockout (MacPPARγKO) mice. C57BL/6 and low-density lipoprotein (LDL) receptor–deficient (LDLR
−/−
) mice were reconstituted with MacPPARγKO or wild-type marrow and challenged with an atherogenic diet. No differences were found in serum lipids between recipients reconstituted with MacPPARγKO and wild-type marrow. In contrast, both C57BL/6 and LDLR
−/−
mice transplanted with MacPPARγKO marrow had significantly larger atherosclerotic lesions than control recipients. In addition, MacPPARγKO→LDLR
−/−
mice had higher numbers of macrophages in atherosclerotic lesions compared with controls. Peritoneal macrophages isolated from the MacPPARγKO mice had decreased uptake of oxidized but not acetylated LDL and showed no changes in either cholesterol efflux or inflammatory cytokine expression. Macrophages from MacPPARγKO mice had increased levels of migration and CC chemokine receptor 2 (CCR2) expression compared with wild-type macrophages.

Conclusion—

Thus, macrophage PPARγ deficiency increases atherosclerosis under conditions of mild and severe hypercholesterolemia, indicating an antiatherogenic role for PPARγ, which may be caused, at least in part, by modulation of CCR2 expression and monocyte recruitment.
Coronary Artery Calcium Outperforms Carotid Artery Intima-Media Thickness as a Noninvasive Index of Prevalent Coronary Artery Stenosis
Authors: Terry James G. , Carr J. Jeffrey , Tang Rong , Evans Gregory W. , Kouba Ethel O. , Shi Rong , Cook Delilah R. , Vieira Jose L.C. , Espeland Mark A. , Mercuri Michele F. , Crouse John R.
Published: June 2005

Objective—

Increased carotid artery intima-media thickness (IMT) and increased coronary artery calcium (CAC) are noninvasive surrogate indices of prevalent coronary artery disease (CAD). We compared CAC to IMT for noninvasive detection of prevalent CAD in participants whose coronary status was identified by coronary angiography.

Methods and Results—

Male and female CAD patients (≥50% stenosis in one or more coronary artery, n=79) and controls (no lumen irregularities, n=93) were identified using coronary angiography. Mean maximum carotid IMT was quantified using B-mode ultrasound and total CAC was measured using ECG-gated helical computed tomography (HCT). Carotid IMT was ≈20% higher in CAD cases compared with controls (
P
<0.001), whereas mean CAC was 1000% higher in CAD cases than controls (
P
<0.0001). In multivariable models adjusted for age and sex, IMT greater than the median (1.13 mm) was associated with 2-fold increase in likelihood of prevalent CAD compared with scores below that cut point (
P
=0.015). CAC scores that exceeded the median score of 92 were associated with 28-fold increase in likelihood of prevalent CAD (
P
<0.0001). Although associations of increased IMT with prevalent CAD were similar in males and females, CAC scores above the median in females were associated with 39-fold increase in odds of prevalent CAD, whereas males with elevated CAC had 19-fold risk of CAD.

Conclusion—

HCT-measured CAC compares favorably with carotid IMT measured by B-mode ultrasound as a noninvasive index of prevalent CAD.
Regulation of Tissue Factor–Mediated Initiation of the Coagulation Cascade by Cell Surface Grp78
Authors: Bhattacharjee Gourab , Ahamed Jasimuddin , Pedersen Brian , El-Sheikh Amr , Mackman Nigel , Ruf Wolfram , Liu Cheng , Edgington Thomas S.
Published: June 2005

Objective—

To test the hypothesis that Grp78 negatively regulates cell surface tissue factor (TF) procoagulant activity and whether this is mediated by physical interaction.

Methods and Results—

Biopanning with phage-displayed peptidyl libraries has identified peptide probes that bind selectively in vivo to the surface of atherosclerotic plaque endothelium. The highest affinity peptide, EKO130, binds 78-kDa glucose regulated protein (Grp78). Grp78 participates in numerous pathological processes, including the regulation of the coagulation cascade, but the mechanism of Grp78 regulation of coagulation is unknown. To characterize this function, we analyzed the effect of Grp78 on TF-mediated procoagulant activity on murine brain endothelial cells (bEND.3) and macrophage-like (RAW) cells, which are relevant in mediation of atherothrombosis. We show that Grp78 is present on the surface of endothelium and monocyte/macrophage-like cells in atherosclerotic lesions. Inhibition of Grp78 resulted in increased procoagulant activity. We demonstrate that Grp78 negatively regulates procoagulant activity by interacting physically with the TF extracellular domain on the cell surface.

Conclusions—

The evidence indicates that Grp78 negatively regulates TF functional activity via direct binding to and functional inhibition of TF. Identification of the mechanism by which Grp78 regulates TF function may advance insight into the pathobiology of atherosclerosis and associated arterial thrombosis.
Atrial Fibrillation in KCNE1-Null Mice
Authors: Temple Joel , Frias Patricio , Rottman Jeffrey , Yang Tao , Wu Yuejin , Verheijck E. Etienne , Zhang Wei , Siprachanh Chanthaphaychith , Kanki Hideaki , Atkinson James B. , King Paul , Anderson Mark E. , Kupershmidt Sabina , Roden Dan M.
Published: June 2005

Although atrial fibrillation is the most common serious cardiac arrhythmia, the fundamental molecular pathways remain undefined. Mutations in
KCNQ1
, one component of a sympathetically activated cardiac potassium channel complex, cause familial atrial fibrillation, although the mechanisms in vivo are unknown. We show here that mice with deletion of the KCNQ1 protein partner KCNE1 have spontaneous episodes of atrial fibrillation despite normal atrial size and structure. Isoproterenol abolishes these abnormalities, but vagomimetic interventions have no effect. Whereas loss of KCNE1 function prolongs ventricular action potentials in humans, KCNE1
−/−
mice displayed unexpectedly shortened atrial action potentials, and multiple potential mechanisms were identified: (1) K
+
currents (total and those sensitive to the KCNQ1 blocker chromanol 293B) were significantly increased in atrial cells from KCNE1
−/−
mice compared with controls, and (2) when CHO cells expressing KCNQ1 and KCNE1 were pulsed very rapidly (at rates comparable to the normal mouse heart and to human atrial fibrillation), the sigmoidicity of
I
Ks
activation prevented current accumulation, whereas cells expressing KCNQ1 alone displayed marked current accumulation at these very rapid rates. Thus, KCNE1 deletion in mice unexpectedly leads to increased outward current in atrial myocytes, shortens atrial action potentials, and enhances susceptibility to atrial fibrillation.
CD31
−
but Not CD31
+
Cardiac Side Population Cells Exhibit Functional Cardiomyogenic Differentiation
Authors: Pfister Otmar , Mouquet Frédéric , Jain Mohit , Summer Ross , Helmes Michiel , Fine Alan , Colucci Wilson S. , Liao Ronglih
Published: June 2005

Heart failure remains a leading cause of morbidity and mortality. The cellular mechanism underlying the development of cardiac dysfunction is a decrease in the number of viable cardiomyocytes. Recent observations have suggested that the adult heart may contain a progenitor cell population. Side population (SP) cells, characterized by a distinct Hoechst dye efflux pattern, have been shown to exist in multiple tissues and are capable of tissue-specific differentiation. In this report, we confirm the existence of a cardiac SP cell population, immunophenotypically distinct from bone marrow SP cells. Moreover, we demonstrate that among cardiac SP cells, the greatest potential for cardiomyogenic differentiation is restricted to cells negative for CD31 expression and positive for stem cell antigen 1 (Sca1) expression (CD31
−
/Sca1
+
). Furthermore, we determine that CD31
−
/Sca1
+
cardiac SP cells are capable of both biochemical and functional cardiomyogenic differentiation into mature cardiomyocytes, with expression of cardiomyocyte-specific transcription factors and contractile proteins, as well as stimulated cellular contraction and intracellular calcium transients indistinguishable from adult cardiomyocytes. We also determine the necessity of cell-extrinsic signaling through coupling, although not fusion, with adult cardiomyocytes in regulating cardiomyogenic differentiation of cardiac SP cells. We, therefore, conclude that CD31
−
/Sca1
+
cardiac SP cells represent a distinct cardiac progenitor cell population, capable of cardiomyogenic differentiation into mature cardiomyocytes through a process mediated by cellular coupling with adult cardiomyocytes.
Ca
2+
Sparks and Waves in Canine Purkinje Cells
Authors: Stuyvers Bruno D. , Dun Wen , Matkovich Scot , Sorrentino Vincenzo , Boyden Penelope A. , ter Keurs Henk E.D.J.
Published: June 2005

We have investigated the subcellular spontaneous Ca
2+
events in canine Purkinje cells using laser scanning confocal microscopy. Three types of Ca
2+
transient were found: (1) nonpropagating Ca
2+
transients that originate directly under the sarcolemma and lead to (2) small Ca
2+
wavelets in a region limited to ≈6-μm depth under the sarcolemma causing (3) large Ca
2+
waves that travel throughout the cell (CWWs). Immunocytochemical studies revealed 3 layers of Ca
2+
channels: (1) channels associated with type 1 IP
3
receptors (IP
3
R
1
) and type 3 ryanodine receptors (RyR
3
) are prominent directly under the sarcolemma; (2) type 2 ryanodine receptors (RyR
2
s) are present throughout the cell but virtually absent in a layer between 2 and 4 μm below the sarcolemma (Sub-SL); (3) type 3 ryanodine receptors (RyR
3
) is the dominant Ca
2+
release channel in the Sub-SL. Simulations of both nonpropagating and propagating transients show that the generators of Ca
2+
wavelets differ from those of the CWWs with the threshold of the former being less than that of the latter. Thus, Purkinje cells contain a functional and structural Ca
2+
system responsible for the mechanism that translates Ca
2+
release occurring directly under the sarcolemma into rapid Ca
2+
release in the Sub-SL, which then initiates large-amplitude long lasting Ca
2+
releases underlying CWWs. The sequence of spontaneous diastolic Ca
2+
transients that starts directly under the sarcolemma and leads to Ca
2+
wavelets and CWWs is important because CWWs have been shown to cause nondriven electrical activity.
Therapy Implications of Transthoracic Echocardiography in Acute Ischemic Stroke Patients
Authors: de Abreu Tiago Tribolet , Mateus Sónia , Correia José
Published: June 2005

Background and Purpose—

Stroke is the third leading cause of death in most Western countries. Cardioembolism might be responsible for 15% to 20% of ischemic strokes. Although atrial fibrillation can be diagnosed by electrocardiography, the remaining causes of cardioembolic stroke are diagnosed by echocardiography. Recent recommendations on the management of acute ischemic stroke fail to consider echocardiography as an essential test in all patients.

Methods—

We conducted a prospective observational study, performing transthoracic echocardiography on all patients admitted in our hospital with ischemic stroke, in sinus rhythm, from January 7, 2002, to October 16, 2003. Findings compatible with heart diseases that would indicate anticoagulation as beneficial were identified.

Results—

Of the 853 patients admitted with ischemic stroke, transthoracic echocardiography was performed on 846 (99.2%). Of the 435 patients with ischemic stroke, in sinus rhythm, 37.2% had findings indicating anticoagulation as beneficial: dilated cardiopathy (19.1%), previous anterior wall myocardial infarction (6.2%), left ventricular systolic dysfunction with an ejection fraction <35% (3.7%), mitral valve stenosis with enlarged left atria (1.6%), intracardiac masses (0.5%), valvular prosthesis (0.2%), and >1 abnormality (5.5%).

Conclusions—

In our study, transthoracic echocardiography had therapy implications in 37.2% of ischemic stroke patients in sinus rhythm. Transthoracic echocardiography should be considered an essential test in all ischemic stroke patients in sinus rhythm.
Arterial Occlusive Lesions Recanalize More Frequently in Women Than in Men After Intravenous Tissue Plasminogen Activator Administration for Acute Stroke
Authors: Savitz Sean I. , Schlaug Gottfried , Caplan Louis , Selim Magdy
Published: June 2005

Background and Purpose—

Previous reports suggest that women achieve better outcome than men after intravenous thrombolysis for ischemic stroke. Coagulation and fibrinolysis differ between sexes. These findings prompted us to investigate possible gender differences in arterial recanalization after intravenous tissue plasminogen activator (IV tPA).

Methods—

We identified 100 consecutive patients who presented with acute ischemic stroke and received IV tPA within 6 hours of onset. Only patients with large artery anterior circulation strokes, as determined by MRI/MRA or CT/CTA before treatment, who had follow-up vascular study within 72 hour after treatment were included. We compared demographics, clinical features, admission medications, symptom-to-needle and treatment-to-repeat vascular imaging times, baseline National Institutes of Health Stroke Severity score, radiological and laboratory data, stroke mechanism, and outcome between the sexes.

Results—

39 patients met all inclusion/exclusion criteria (22 men and 17 women). The recanalization rate was significantly higher in women (94% versus 59%;
P
=0.02). This difference remained statistically significant after excluding patients whose strokes were attributed to internal carotid artery occlusive lesions, and when the analysis was limited to those treated within 3 hours of stroke onset. All other confounding variables did not differ significantly between the sexes.

Conclusions—

In our cohort, vascular occlusive lesions were more likely to recanalize in women than men in response to IV tPA. These preliminary findings need to be validated in larger prospective studies.
Measurement of Community Ambulation After Stroke
Authors: Lord Susan E. , Rochester Lynn
Published: June 2005

Background and Purpose—

This report considers the measurement of community ambulation for people with stroke. The conceptual issues underlying measurement of community ambulation are reviewed, and tests that measure either the task itself or at least some of its components are identified and discussed.

Conclusions—

The findings from this review suggest that although some progress has been made toward identifying community ambulation as a stand-alone entity, reliable and valid measures have not yet been developed. Gait speed, which is used often as a proxy measure for community ambulation, does not consistently reflect the level of community ambulation attained, and continued reliance on its use, particularly the 10-m timed walk, is misplaced. The limitations of the measures reviewed here point toward self-report as being the most useful outcome for current clinical use. However, this report highlights the need for research to first inform a theoretical framework for the measurement of community ambulation, from which a measurement tool or a battery of measurements can be developed and tested.
Transcranial Low-Frequency Ultrasound-Mediated Thrombolysis in Brain Ischemia
Authors: Daffertshofer Michael , Gass Achim , Ringleb Peter , Sitzer Matthias , Sliwka Ulrich , Els Thomas , Sedlaczek Oliver , Koroshetz Walter J. , Hennerici Michael G.
Published: June 2005

Background—

Clinical studies using ultrasound at diagnostic frequencies in transcranial Doppler devices provided encouraging results in enhancing thrombolysis with tissue plasminogen activator (tPA) in acute stroke. Low-frequency ultrasound does not require complex positioning procedures, penetrates through the skull better, and has been demonstrated to accelerate thrombolysis with tPA in animal experiments in wide cerebrovascular territories without hemorrhagic side effects. We therefore conducted the first multicenter clinical trial to investigate safety of tPA plus low-frequency ultrasound (300 kHz).

Methods—

Acute stroke patients within a 6-hour time window were included (National Institutes of Health Stroke Scale scores >4). Magnetic resonance imaging (MRI) was used to document vascular occlusion and to rule out cerebral hemorrhage. Patients were allocated to combination therapy alternately; the first patient received tPA only, the second patient received tPA plus ultrasound, etc. Follow-up included serial MRI directly thereafter and 24 hours later to confirm recanalization and tissue imaging. Clinical recovery was measured after treatment and 3 months later.

Results—

26 patients (70.4±9.7 years) entered the trial (12 tPA, 14 tPA plus ultrasound). The study was prematurely stopped because 5 of 12 patients from the tPA only group but 13 of 14 patients treated with the tPA plus ultrasound showed signs of bleeding in MRI (
P
<0.01). Within 3 days of treatment, 5 symptomatic hemorrhages occurred within the tPA plus ultrasound group. At 3 months, neither morbidity nor treatment-related mortality or recanalization rates differed between both groups.

Conclusions—

This study demonstrated bioeffects from low-frequency ultrasound that caused an increased rate of cerebral hemorrhages in patients concomitantly treated with intravenous tPA.
Predictors of Early Arterial Reocclusion After Tissue Plasminogen Activator-Induced Recanalization in Acute Ischemic Stroke
Authors: Rubiera Marta , Alvarez-Sabín José , Ribo Marc , Montaner Joan , Santamarina Esteban , Arenillas Juan F. , Huertas Rafael , Delgado Pilar , Purroy Francisco , Molina Carlos A.
Published: June 2005

Background and Purpose—

We aimed to determine clinical and hemodynamic predictors of early reocclusion (RO) in stroke patients treated with intravenous tissue plasminogen activator (tPA).

Methods—

We studied 142 consecutive stroke patients with a documented middle cerebral artery (MCA) occlusion treated with intravenous tPA. All patients underwent carotid ultrasound and transcranial Doppler (TCD) examination before tPA bolus. National Institutes of Health Stroke Scale (NIHSS) scores were performed at baseline and serially for <24 hours. TCD monitoring of MCA recanalization (RE) and RO was performed during the first 2 hours after tPA bolus and repeated when clinical deterioration occurred <24 hours after documented RE in absence of intracranial hemorrhage.

Results—

After 1 hour of tPA administration, RE occurred in 84 (61%) patients (53 partial, 31 complete). Of these, 21 (25%) patients worsened after an initial improvement and 17 (12%) of them showed RO on TCD. RO was identified at a mean time of 65±55 minutes after documented RE. RO was associated (
P
=0.034) with a lower degree of 24-hour NIHSS score improvement than sustained RE, and a higher modified Rankin scale score at 3 months (
P
=0.002). Age older than 75 years (
P
=0.012), previous antiplatelet treatment (
P
=0.048), baseline NIHSS score >16 points (
P
=0.009), higher leukocytes count (
P
=0.042), beginning of RE <60 minutes after tPA bolus (
P
=0.039), and ipsilateral severe carotid stenosis/occlusion (
P
=0.001) were significantly associated with RO. In a logistic regression model, NIHSS score >16 at baseline (odds ratio [OR], 7.1; 95% CI, 1.3 to 32) and severe ipsilateral carotid disease (OR, 13.3; 95% CI, 3.2 to 54) remained as independent predictors of RO.

Conclusions—

Stroke severity and ipsilateral severe carotid artery disease independently predict RO after tPA-induced MCA RE.
Angiopoietin-2 Facilitates Vascular Endothelial Growth Factor-Induced Angiogenesis in the Mature Mouse Brain
Authors: Zhu Yiqian , Lee Chanhung , Shen Fanxia , Du Rose , Young William L. , Yang Guo-Yuan
Published: June 2005

Background and Purpose—

A better understanding of angiogenic factors and their effects on cerebral angiogenesis is necessary for the development of effective therapeutic strategies for ischemic brain injury. Vascular endothelial growth factor (VEGF) has been shown to induce angiogenesis in the adult mouse brain. However, the function of angiopoietin-2 (Ang-2) in cerebral angiogenesis has not been clarified. The goal of this study was to identify the combined effects of VEGF and Ang-2 on cerebral angiogenesis and the blood–brain barrier (BBB).

Methods—

Six groups of 6 adult male CD-1 mice underwent AdlacZ (viral vector control), AdVEGF, AdAng2, VEGF protein, VEGF protein plus AdAng2, or saline (negative control) injection. Microvessels were counted using lectin staining on tissue sections after 2 weeks of treatment. Matrix metalloproteinase-9 (MMP-9) activity was determined by zymography. The presence of zonula occludens-1 (ZO-1) protein was determined by Western blot and immunohistochemistry.

Results—

Mice treated with VEGF protein infusion plus AdAng-2 significantly increased microvessel counts relative to all other groups (
P
<0.05). The changes in MMP-9 activity paralleled the reduced ZO-1 expression in the VEGF plus Ang-2–treated group compared with the other 5 groups (
P
<0.05). Double-labeled immunostaining demonstrated that ZO-1–positive staining was significantly decreased on the microvessel wall in the VEGF plus Ang-2–treated group.

Conclusions—

Our study demonstrates that the combination of VEGF and Ang-2 promotes more angiogenesis compared with VEGF alone. Furthermore, the combination of VEGF and Ang-2 may lead to BBB disruption because it increases MMP-9 activity and inhibits ZO-1 expression.
Role of c-Jun N-Terminal Kinase in Cerebral Vasospasm After Experimental Subarachnoid Hemorrhage
Authors: Yatsushige Hiroshi , Yamaguchi Mitsuo , Zhou Changman , Calvert John W. , Zhang John H.
Published: June 2005

Background and Purpose—

Inflammation could play a role in cerebral vasospasm after subarachnoid hemorrhage (SAH). SP600125 a c-Jun N-terminal kinase (JNK) inhibitor reduces inflammation. The present study examined if SP600125 could reduce cerebral vasospasm.

Methods—

Twenty-seven dogs were assigned to 5 groups: control, SAH, SAH plus dimethyl sulfoxide (DMSO), SAH plus SP600125 (10 μmol/L), and SAH plus SP600125 (30 μmol/L). SAH was induced by the injection of autologous blood into the cisterna magna on day 0 and day 2. Angiograms were evaluated on day 0 and day 7. The behavior of the dogs was evaluated daily. The activation of the JNK pathway, the infiltration of leukocytes, and the production of cytokines were also evaluated.

Results—

Severe vasospasm was observed in the basilar artery of SAH and DMSO dogs. The JNK signaling pathway was activated in the basilar artery after SAH and SP600125 reduced angiographic and morphological vasospasm and improved behavior scores with a concomitant reduction of infiltrated leukocytes and IL-6 production.

Conclusions—

These results demonstrate that SP600125 attenuated cerebral vasospasm through a suppressed inflammatory response, which may provide a novel therapeutic target for cerebral vasospasm.
Stroke Presentation and Outcome in Developing Countries
Authors: Garbusinski Johanne M. , van der Sande Marianne A.B. , Bartholome Emmanuel J. , Dramaix Michèle , Gaye Alieu , Coleman Rosalind , Nyan Ousman A. , Walker Richard W. , McAdam Keith P.W.J. , Walraven Gys E.
Published: June 2005

Background and Purpose—

Despite increasing burden of stroke in Africa, prospective descriptive data are rare. Our objective was to describe, in The Gambia, the clinical outcome of stroke patients admitted to the Royal Victoria Teaching Hospital in the capital Banjul, to assess mortality and morbidity, and propose preventive and therapeutic measures.

Methods—

Prospective data were collected on consecutive patients older than 15 years old admitted between February 2000 and February 2001 with the diagnosis of nonsubarachnoid stroke. Risk factors, clinical characteristics, and social consequences were assessed using a modified National Institutes of Health Stroke Scale (mNIHSS), the Barthel Activity in Daily Living scale, the Siriraj score for subtypes, and the Bamford criteria for location/extension. Patients were followed-up at home up to 1 year after discharge.

Results—

Ninety-one percent (148/162) of eligible patients were enrolled and followed-up. Hypertension and smoking were the most prevalent risk factors. Severity was high at admission, especially in women, and was strongly correlated to the outcome. mNIHSS and consciousness level on admission were strong predictors of the mortality risk. Swallowing difficulties at admission, fever, lung infection, and no aspirin treatment were, independently, risk factors for a lethal outcome susceptible to being addressed by treatment. Mortality was 41% in-hospital and 62% after 1 year. In survivors, autonomy levels improved over time. Drug compliance was poor. At home, family members provided care. Long-term socioeconomic and cultural activities were affected in most patients.

Conclusions—

Case-fatality was high compared with Western cohorts. Preventive measures can be developed. Rational treatment, in the absence of head imaging for initial assessment, requires adapted protocols. Providers should be trained, both at hospital and community levels.