bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of synaptic vesicles pools within motor nerve terminals during short-term facilitation and neuromodulation
Authors: Logsdon S. , Johnstone A. F. M. , Viele K. , Cooper R. L.
Published: October 2005

The reserve pool (RP) and readily releasable pool (RRP) of synaptic vesicles within presynaptic nerve terminals were physiologically differentiated into distinctly separate functional groups. This was accomplished in glutamatergic nerve terminals by blocking the glutamate transporter with dl-threo-β-benzyloxyaspartate (TBOA; 10 μM) during electrical stimulation with either 40 Hz of 10 pulses within a train or 20- or 50-Hz continuous stimulation. The 50-Hz continuous stimulation decreased the excitatory postsynaptic potential amplitude 60 min faster than for the 20-Hz continuous stimulation in the presence of TBOA ( P < 0.05). There was no significant difference between the train stimulation and 20-Hz continuous stimulation in the run-down time in the presence of TBOA. After TBOA-induced synaptic depression, the excitatory postsynaptic potentials were rapidly (<1 min) revitalized by exposure to serotonin (5-HT, 1 μM) in every preparation tested ( P < 0.05). At this glutamatergic nerve terminal, 5-HT promotes an increase probability of vesicular docking and fusion. Quantal recordings made directly at nerve terminals revealed smaller quantal sizes with TBOA exposure with a marked increase in quantal size as well as a continual appearance of smaller quanta upon 5-HT treatment after TBOA-induced depression. Thus 5-HT was able to recruit vesicles from the RP that were not rapidly depleted by acute TBOA treatment and electrical stimulation. The results support the notion that the RRP is selectively activated during rapid electrical stimulation sparing the RP; however, the RP can be recruited by the neuromodulator 5-HT. This suggests at least two separate kinetic and distinct regulatory paths for vesicle recycling within the presynaptic nerve terminal.
Vanilloid type 1 receptor and the acid-sensing ion channel mediate acid phosphate activation of muscle afferent nerves in rats
Authors: Gao Zhaohui , Henig Oze , Kehoe Valerie , Sinoway Lawrence I. , Li Jianhua
Published: October 2005

Reflex cardiovascular responses to contracting skeletal muscle are mediated by mechanical and metabolic stimulation of thin-fiber muscle afferents. Diprotonated phosphate (H2PO4−) excites those thin-fiber nerves and evokes the muscle pressor reflex. The receptors mediating this response are unknown. Thus we examined the role played by purinergic receptors, vanilloid type 1 receptors (VR1), and acid-sensing ion channels (ASIC) in mediating H2PO4−-evoked pressor responses. Phosphate and blocking agents were injected into the arterial blood supply of the hindlimb muscles of 53 decerebrated rats. H2PO4− (86 mM, pH 6.0) increased mean arterial pressure by 25 ± 2 mmHg, whereas monoprotonated phosphate (HPO42−, pH 7.5) had no effect. Pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (a purinergic receptor antagonist, 2 mM) did not block the response. However, capsazepine (a VR1 antagonist, 1 mg/kg) attenuated the reflex by 60% and amiloride (an ASIC blocker, 6 μg/kg) by 52%. Of note, the H2PO4−-induced pressor response was attenuated by 87% when both capsazepine and amiloride were injected before the H2PO4−. In conclusion, VR1 and ASIC mediate the pressor response due to H2PO4−. The H2PO4−-evoked response was greater when VR1 and ASIC blockers were given simultaneously than when the respective blockers were given separately. Our laboratory's previous study has shown that H+ stimulates ASIC (but not VR1) on thin-fiber afferent nerves in evoking the reflex response. Thus VR1 and ASIC are likely to play a coordinated and interactive role in processing the muscle afferent response to H2PO4−. Furthermore, the physiological mechanisms mediating the response to H+ and H2PO4− are likely to be different.
Delayed threshold for active cutaneous vasodilation in patients with Type 2 diabetes mellitus
Authors: Wick Diane E. , Roberts Shelly K. , Basu Ananda , Sandroni Paola , Fealey Robert D. , Sletten David , Charkoudian Nisha
Published: October 2005

Epidemiological evidence suggests decreased heat tolerance in patients with Type 2 diabetes mellitus (T2DM), but it is not known whether the mechanisms involved in thermoregulatory control of skin blood flow are altered in these patients. We tested the hypothesis that individuals with T2DM have a delayed internal temperature threshold for active cutaneous vasodilation during whole body heating compared with healthy control subjects. We measured skin blood flow using laser-Doppler flowmetry (LDF), internal temperature (Tor) via sublingual thermocouple, and mean arterial pressure via Finometer at baseline and during whole body heating in 9 T2DM patients and 10 control subjects of similar age, height, and weight. At one LDF site, sympathetic noradrenergic neurotransmission was blocked by local pretreatment with bretylium tosylate (BT) to isolate the cutaneous active vasodilator system. Whole body heating was conducted using a water-perfused suit. There were no differences in preheating Torbetween groups ( P > 0.10). Patients with T2DM exhibited an increased internal temperature threshold for the onset of vasodilation at both untreated and BT-treated sites. At BT-treated sites, Torthresholds were 36.28 ± 0.07°C in controls and 36.55 ± 0.05°C in T2DM patients ( P < 0.05), indicating delayed onset of active vasodilation in patients. Sensitivity of vasodilation was variable in both groups, with no consistent difference between groups ( P > 0.05). We conclude that altered control of active cutaneous vasodilation may contribute to impaired thermoregulation in patients with T2DM.
Inhibition of NADPH oxidase improves impaired reactivity of pial arterioles during chronic exposure to nicotine
Authors: Fang Qin , Sun Hong , Arrick Denise M. , Mayhan William G.
Published: October 2005

Our goals were to determine whether chronic exposure to nicotine alters nitric oxide synthase (NOS)-dependent reactivity of cerebral (pial) arterioles and to identify a potential role for NADPH oxidase in impaired NOS-dependent responses during chronic exposure to nicotine. We measured in vivo diameter of pial arterioles to NOS-dependent (acetylcholine and ADP) and -independent (nitroglycerin) agonists in saline-treated rats and rats chronically treated with nicotine (2 mg·kg−1·day−1 for 2 wk via an osmotic minipump). We found that NOS-dependent, but not -independent, vasodilatation was impaired in nicotine-treated compared with saline-treated rats. In addition, the production of superoxide anion (lucigenin chemiluminescence) was increased in rats treated with nicotine compared with saline-treated rats. Furthermore, using Western blot analysis, we found that chronic exposure to nicotine increased p47phox protein in the parietal cortex. Finally, we found that apocynin (40 mg·kg−1·day−1) in the drinking water to inhibit NADPH oxidase alleviated impaired NOS-dependent cerebral vasodilatation in nicotine treated rats but did not alter NOS-dependent responses in saline treated rats and did not alter NOS-independent reactivity in saline- or nicotine-treated rats. These findings suggest that chronic exposure to nicotine impairs NOS-dependent dilatation of pial arterioles by a mechanism that appears to be related to the formation of superoxide anion via activation of NADPH oxidase.
Safety of Withholding Anticoagulant Therapy in Patients Who Have Clinically Suspected Pulmonary Embolism and Negative Results on Helical Computed Tomography
Authors: Pérez de Llano L.A. , Veres Racamonde A. , Ortiz Piquer M. , López Díaz M.J. , Janeiro Amela M. , Méndez Maroto L. , Vázquez Caruncho M. , Gómez Lafoz J.
Published: October 2005

Background: Several studies have focused on the safety of withholding anticoagulant therapy in patients with negative results on helical computed tomography (CT). However, these studies were either retrospective or had a selection bias, since spiral CT was performed only in selected patients. Moreover, no special attention has been directed towards an alternative diagnosis which might explain patients’ signs and symptoms. Objectives: To determine the safety of withholding anticoagulants in patients with clinically suspected pulmonary embolism (PE) and negative CT results when ultrasonography (US) was performed only in patients with clinical suspicion of deep vein thrombosis (DVT). Another goal was to evaluate the effect of CT findings on the final clinical diagnosis. Methods: Among 192 consecutive patients who underwent CT for possible acute PE, 98 patients had negative images and 88 of them – without clinical suspicion of DVT – were prospectively followed up for 3 months for evidence of subsequent thromboembolic disease. They did not receive anticoagulation. Clinical probability of PE was assessed applying the Geneva score. These patients were also classified into several diagnostic categories according to the CT findings and clinical presentation. In addition, all patients who were alive (or a member of his or her family) were interviewed by phone once the last patient’s follow-up was completed. Results: One patient was lost to follow-up. Among the remaining 87 patients (35 with low, 47 with intermediate and 5 with high clinical probability), subsequent thromboembolic disease was found in 1 (1.1%; 95%CI: 0.03–6.2%). Two patients died during the follow-up period, but no deaths were attributed to PE. Alternative diagnoses were: nonspecific thoracic pain (43.3%), nonspecific pleuritis (19.5%), pneumonia (18.4%), other (18.8%). The telephone survey was performed in 74 patients (median follow-up: 11 months; range: 4–23). None of them had newly diagnosed episodes of PE and none of them had received anticoagulation for any reason. Conclusions: With the limitations of a small single-center series, our data suggest that withholding anticoagulation in patients with suspected acute PE and negative CT results appears to be safe when the clinical probability of PE is assessed as low or intermediate. This technique also provides useful information to pose an alternative diagnosis. US could be avoided in patients without clinical suspicion of DVT.
Comparative Clinicopathology of Obliterative Bronchiolitis and Diffuse Panbronchiolitis
Authors: Homma Sakae , Sakamoto Susumu , Kawabata Masateru , Kishi Kazuma , Tsuboi Eiyasu , Motoi Noriko , Hebisawa Akira , Yoshimura Kunihiko
Published: October 2005

Background: The progressive airway obliteration caused by obliterative bronchiolitis (OB) has been widely noted in the world. In contrast, the obstructive respiratory disorder caused by diffuse panbronchiolitis (DPB) has been reported mainly from Japan. Therefore, there might be a considerable overlap between OB and DPB in Japan. Objectives and Methods: To clarify the clinicopathological similarities as well as the differences between OB and DPB, 15 patients with OB and 6 patients with DPB were evaluated clinicopathologically. Results: The underlying disorders in OB were graft-versus-host disease (GVHD) in 7, rheumatoid arthritis in 3, Kartagener’s syndrome in 2, and polymyositis/dermatomyositis, non-tuberculous mycobacterial disease and mycoplasmal pneumonia in one each. The lung pathology demonstrated that the primary obstructive lesions were in the membranous bronchioli in OB. In contrast, they were confined to the respiratory bronchioli in DPB. In addition, OB was classified into two major morphologic types, namely, constrictive and cellular. Clinical manifestations included cough and/or dyspnea in 13 with OB and in 6 with DPB, chronic parasinusitis in 3 with cellular OB and in 6 with DPB. The pulmonary function tests revealed obstructive impairments in all patients with OB and DPB. The chest CT images showed small centrilobular nodules in 64% of those with OB and in all with DPB. The prognosis of constrictive OB was worse than that of cellular OB and DPB. Conclusions: This study demonstrated that histopathologically marked differences existed between OB and DPB, although striking similarities in clinical manifestations were also noted in both diseases.
Melatonin Administration Acutely Decreases the Diffusing Capacity of Carbon Monoxide in Human Lungs
Authors: Vardar Selma Arzu , Altun Gülay Durmus , Günerbüyük Caner , Hatipoglu Osman Nuri , Mert Selva , Kaymak Kadir
Published: October 2005

Background: Most physiological measurements of the pulmonary diffusing capacity use carbon monoxide (CO) as a tracer gas. Similar to CO, melatonin binds the hemoglobin in the blood. Objective: The present study was designed to assess the effect of exogenous melatonin administration on pulmonary functions including diffusing capacity for carbon monoxide (DLCO) in healthy subjects. Methods: The study was performed in a randomized, double-blind, placebo-controlled manner. DLCO was measured in 22 healthy male volunteers (age 18–25 years) who were randomized to melatonin (n = 11) and placebo administration (n = 11). At baseline, DLCO, alveolar volume (VA) and other spirometric parameters such as forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and maximal voluntary ventilation (MVV) were measured. DLCO was then corrected for the hemoglobin concentration. Measurements were repeated in a double-blind fashion 60 min after the administration of melatonin (1 mg) or placebo. Results: DLCO was significantly decreased (39.31 ± 4.75 vs. 34.82 ± 6.18 ml/min/mm Hg) 60 min after the melatonin administration (p = 0.01), while FEV1, FVC, FEV1/FVC, PEF and MVV values did not demonstrate significant differences. Placebo administration did not result in significant alteration in any of these parameters. Conclusions: In healthy subjects, oral administration of melatonin acutely influences the DLCO without affecting other pulmonary function test results. We conclude that melatonin may have a reducing effect on the DLCO in the lungs.
Assessment of the Pulmonary Volume Pulse in Idiopathic Pulmonary Arterial Hypertension by Means of Electrical Impedance Tomography
Authors: Smit Henk J. , Vonk-Noordegraaf Anton , Boonstra Anco , de Vries Peter M. , Postmus Pieter E.
Published: October 2005

Background: Electrical impedance tomography (EIT) is a non-invasive imaging technique which can be used to measure the blood volume changes in the pulmonary vascular bed during the cardiac cycle. Study Objectives: This study was performed to evaluate the differences in the EIT signal of the pulmonary vascular bed between healthy subjects and patients with idiopathic pulmonary arterial hypertension (IPAH), who are known to have a remodelled pulmonary vascular bed. Patients and Methods: Twenty-one patients (17 females, 4 males) with IPAH and 30 healthy controls (5 females, 25 males) were measured. EIT measurements were performed in duplicate, on the same day as right heart catheterization to obtain haemodynamic data. The maximal impedance change during systole (Δ Zsys) was used as a measure of the pulmonary volume pulse and expressed in arbitrary units (AU). Total lung capacity, spirometric values and diffusion capacity for carbon monoxide were measured as well. Results: Mean Δ Zsys was 215 ± 58 × 10–2 AU (95% CI 193 × 10–2 to 236 × 10–2) in the healthy subjects and 78 ± 27 × 10–2 AU (95% CI 66 × 10–2 to 91 × 10–2) in the IPAH patient group (p < 0.0001). No significant correlation was found between Δ Zsys and any of the haemodynamic or lung function data. Conclusion: The impedance pulsation of the pulmonary vascular bed is reduced in IPAH in comparison with controls, indicating a reduced volume pulse. This might represent the reduced cross section area, as well as the reduced compliance and number of the pulmonary vessels in these patients.
Occupational Asthma Related to Mouse Allergen Exposure and Rhinoconjunctivitis due to Collagenase Inhalation in a Laboratory Technician
Authors: Muñoz X. , Gómez-Ollés S. , Cruz M.J. , Morell F.
Published: October 2005

We describe the case of a 27-year-old patient working in a research laboratory, who developed occupational asthma to mouse proteins and presented symptoms of rhinoconjunctivitis caused by manipulation of collagenase. Specific inhalation challenge confirmed the diagnosis of occupational asthma to mouse proteins, whereas specific challenge with collagenase only evoked symptoms of rhinitis and conjunctivitis. SDS-PAGE and Western blot analysis for collagenase showed that the patient’s IgE antibodies bound specifically to a protein with a molecular weight of 92 kDa. Hence, this was an unusual case of double sensitization. The sensitization to collagenase presented in this report may represent a new occupational disease in technicians working in medical or research laboratories.
Impact of Ventilation Parameters and Duration of Ventilator Use on Non-Invasive Home Ventilation in Restrictive Thoracic Disorders
Authors: Budweiser Stephan , Heinemann Frank , Fischer Wolfgang , Dobroschke Jakob , Wild Peter J. , Pfeifer Michael
Published: October 2005

Background: Non-invasive positive pressure ventilation (NPPV) is an accepted treatment option for chronic ventilatory failure due to restrictive thoracic disorders. Objective: The impact of ventilation setting and the duration of ventilator use on changes in physiological and functional parameters has not yet been evaluated. Methods: Effects of NPPV on body plethysmographic parameters, blood gas tension and inspiratory muscle function up to 12 months were analyzed in 44 patients with thoracic cage abnormalities in a clinical stable condition. Furthermore, the influence of ventilator parameters and the duration of ventilator use on these changes was determined. Results: A significant improvement in blood gas parameters (PaCO2, PaO2 and base excess; p < 0.001), lung volumes (VC, TLC and FEV1; p < 0.001) and inspiratory muscle function (PImax, P0.1; p < 0.01 and p < 0.05) was found after 3.8 ± 0.8 months of treatment. As shown by a subgroup analysis, changes were already achieved within the first 3 months of NPPV and then remained stable over time. Improvements in VC were positively correlated with IPAP (r = 0.55; p < 0.001). Reduction in PaCO2 was positively correlated with the quotient (IPAP – EPAP)/weight (r = 0.55; p < 0.001). No correlation could be detected between changes in functional parameters and the duration of ventilator use. Conclusions: NPPV can improve blood gas parameters, lung volume and inspiratory muscle function in thoracic restrictive disorders. To best utilize the potential of NPPV treatment, it seems to be more effective to optimize pressure levels than to extend the duration of ventilation.
Peroxynitrite Causes Endoplasmic Reticulum Stress and Apoptosis in Human Vascular Endothelium
Authors: Dickhout Jeffrey G. , Hossain Gazi S. , Pozza Lindsay M. , Zhou Ji , Lhoták Šárka , Austin Richard C.
Published: October 2005

Objective—

Peroxynitrite, a potent oxidant generated by the reaction of NO with superoxide, has been implicated in the promotion of atherosclerosis. We designed this study to determine whether peroxynitrite induces its proatherogenic effects through induction of endoplasmic reticulum (ER) stress.

Methods and Results—

Human vascular endothelial cells treated with Sin-1, a peroxynitrite generator, induced the expression of the ER chaperones GRP78 and GRP94 and increased eIF2α phosphorylation. These effects were inhibited by the peroxynitrite scavenger uric acid. Sin-1 caused the depletion of ER–Ca
2+
, an effect known to induce ER stress, resulting in the elevation of cytosolic Ca
2+
and programmed cell death (PCD). Sin-1 treatment was also found, via 3-nitrotyrosine and GRP78 colocalization, to act directly on the ER. Adenoviral-mediated overexpression of GRP78 in endothelial cells prevented Sin-1–induced PCD. Consistent with these in vitro findings, 3-nitrotyrosine was observed and colocalized with GRP78 in endothelial cells of early atherosclerotic lesions from apolipoprotein E–deficient mice.

Conclusions—

Peroxynitrite is an ER stress-inducing agent. Its effects include the depletion of ER–Ca
2+
, a known mechanism of ER stress induction. The observation that 3-nitrotyrosine–containing proteins colocalize with markers of ER stress within early atherosclerotic lesions suggests that peroxynitrite contributes to atherogenesis through a mechanism involving ER stress.
Stimulated Tissue Plasminogen Activator Release as a Marker of Endothelial Function in Humans
Authors: Oliver James J. , Webb David J. , Newby David E.
Published: October 2005

The initiation, modulation, and resolution of thrombus associated with eroded or unstable coronary plaques are critically dependent on the efficacy of endogenous fibrinolysis. This is dependent on the cellular function of the surrounding endothelium and vascular wall. In particular, the acute release of tissue plasminogen activator from the endothelium makes an important contribution to the defense against intravascular thrombosis. Here, we describe the rationale and methodology for, and clinical relevance of, assessing acute endothelial tissue plasminogen activator release in humans. The investigation of endothelial fibrinolytic function has the potential to provide major new insights into the pathophysiology of cardiovascular disease, and to shape future therapeutic interventions.
Intrasarcoplasmic Amyloidosis Impairs Proteolytic Function of Proteasomes in Cardiomyocytes by Compromising Substrate Uptake
Authors: Chen Quanhai , Liu Jin-Bao , Horak Kathleen M. , Zheng Hanqiao , Kumarapeli Asangi R.K. , Li Jie , Li Faqian , Gerdes A. Martin , Wawrousek Eric F. , Wang Xuejun
Published: October 2005

The presence of increased ubiquitinated proteins and amyloid oligomers in failing human hearts strikingly resembles the characteristic pathology in the brain of many neurodegenerative diseases. The ubiquitin–proteasome system (UPS) is responsible for degradation of most cellular proteins and plays essential roles in virtually all cellular processes. UPS impairment by aberrant protein aggregation was previously shown in cell culture but remains to be demonstrated in intact animals. Mechanisms underlying the impairment are poorly understood. We report here that UPS proteolytic function is severely impaired in the heart of a mouse model of intrasarcoplasmic amyloidosis caused by cardiac-restricted expression of a human desmin–related myopathy-linked missense mutation of αB-crystallin (CryAB
R120G
). The UPS impairment was detected before cardiac hypertrophy, and failure became discernible, suggesting that defective protein turnover likely contributes to cardiac remodeling and failure in this model. Further analyses reveal that the impairment is likely attributable to insufficient delivery of substrate proteins into the 20S proteasomes, and depletion of key components of the 19S subcomplex may be responsible. The derangement is likely caused by aberrant protein aggregation rather than loss of function of the CryAB gene because UPS malfunction was not evident in CryAB-null hearts and inhibition of aberrant protein aggregation by Congo red or a heat shock protein significantly attenuated CryAB
R120G
-induced UPS malfunction in cultured cardiomyocytes. Because of the central role of the UPS in cell regulation and the high intrasarcoplasmic amyloidosis prevalence in failing human hearts, our data suggest a novel pathogenic process in cardiac disorders with abnormal protein aggregation.
Ca2+Influx–Induced Sarcoplasmic Reticulum Ca2+Overload Causes Mitochondrial-Dependent Apoptosis in Ventricular Myocytes
Authors: Chen Xiongwen , Zhang Xiaoying , Kubo Hajime , Harris David M. , Mills Geoffrey D. , Moyer Jed , Berretta Remus , Potts Sabine Telemaque , Marsh James D. , Houser Steven R.
Published: October 2005

Increases in Ca2+influx through the L-type Ca2+channel (LTCC, Cav1.2) augment sarcoplasmic reticulum (SR) Ca2+loading and the amplitude of the cytosolic Ca2+transient to enhance cardiac myocyte contractility. Our hypothesis is that persistent increases in Ca2+influx through the LTCC cause apoptosis if the excessive influx results in SR Ca2+overload. Feline ventricular myocytes (VMs) in primary culture were infected with either an adenovirus (Ad) containing a rat Cav1.2 β2asubunit-green fluorescent protein (GFP) fusion gene (Adβ2a) to increase Ca2+influx or with AdGFP as a control. Significantly fewer β2a-VMs (21.4±5.6%) than GFP-VMs (99.6±1.7%) were viable at 96 hours. A fraction of β2a-VMs (20.8±1.8%) contracted spontaneously (SC-β2a-VMs), and viability was significantly correlated with the percentage of SC-β2a-VMs. Higher percentages of apoptotic nuclei, DNA laddering, and cytochrome C release were detected in β2a-VMs. This apoptosis was prevented with pancaspase or caspase-3 or caspase-9 inhibitors. L-type calcium current (ICa-L) density was greater in β2a-VMs (23.4±2.8 pA/pF) than in GFP-VMs (7.6±1.6 pA/pF). SC-β2a-VMs had higher diastolic intracellular Ca2+(Indo-1 ratio: 1.1±0.1 versus 0.7±0.03,P<0.05) and systolic Ca2+transients (1.89±0.27 versus 0.80±0.08) than GFP-VMs. Inhibitors of Ca2+influx, SR Ca2+uptake and release, mitochondrial Ca2+uptake, mitochondrial permeation transition pore, calpain, and Bcl-2-associated X protein protected β2a-VMs from apoptosis. These results show that persistent increases in Ca2+influx through the ICa-Lenhance contractility but lead to apoptosis through a mitochondrial death pathway if SR Ca2+overload is induced.
NADPH Oxidase Activity and Function Are Profoundly Greater in Cerebral Versus Systemic Arteries
Authors: Miller Alyson A. , Drummond Grant R. , Schmidt Harald H.H.W. , Sobey Christopher G.
Published: October 2005

Recent studies suggest that the superoxide generating enzyme NADPH oxidase may play a functional role in regulating cerebral vascular tone. We tested whether the activity, function, and expression of NADPH oxidase differs between rat cerebral and systemic arteries. Superoxide production by basilar (BA), middle cerebral (MCA), carotid (CA), renal (RA), and mesenteric (MA) arteries and aorta (AO) was measured using lucigenin-enhanced chemiluminescence. Superoxide production from NADPH oxidase was localized and semiquantified using dihydroethidium. Vascular functional responses were assessed in a myograph or organ bath. Vascular Nox4 protein expression was measured using Western blotting. Superoxide production (basal or in response to NADPH or angiotensin II) in the intracranial arteries, BA, and MCA was 10- to 100-fold greater than in AO, CA, RA, or MA. Similar results were found using either intact vessels or arterial homogenates, and were associated with 10-fold greater expression of Nox4 in the BA versus AO, CA, and MA. Superoxide production was attenuated by the NADPH oxidase inhibitors, diphenyleneiodonium, apocynin, and gp91ds-tat. NADPH and H
2
O
2
were strong relaxing stimuli in the BA, where the H
2
O
2
scavenger catalase, as well as apocynin, attenuated these relaxations and also augmented contractions to angiotensin II. NADPH oxidase activity is markedly higher in intracranial versus systemic arteries, in association with higher Nox4 expression. In cerebral arteries, endogenous H
2
O
2
derived from NADPH oxidase activation appears to cause relaxation and is able to offset angiotensin II-induced constriction. These data are consistent with the concept that NADPH oxidase-derived reactive oxygen species modulate cerebral vascular tone under physiological conditions.
Haplotype Effect of the Matrix Metalloproteinase-1 Gene on Risk of Myocardial Infarction
Authors: Pearce Eve , Tregouet David-Alexandre , Samnegård Ann , Morgan Angharad R. , Cox Charles , Hamsten Anders , Eriksson Per , Ye Shu
Published: October 2005

Myocardial infarction (MI) is commonly caused by atherosclerotic plaque rupture following excessive degradation of collagen fibers in the atherosclerotic lesion. We investigated whether interindividual variability in risk of MI was related to polymorphisms in the gene encoding matrix metalloproteinase (MMP)-1, a key fibrillar collagen–degrading enzyme. Several single nucleotide polymorphisms in the MMP1 gene promoter were identified following sequencing DNA samples from 30 individuals. An analysis of the polymorphisms in a cohort of British whites with coronary atherosclerosis, including 639 patients with MI and 538 non-MI subjects, revealed a haplotype effect of the −519A>G and −340T>C polymorphisms on risk of MI, with the A
−519
-C
−340
and G
−519
-T
−340
haplotypes being protective (odds ratio=0.70 [0.57 to 0.86];
P
=0.0007), whereas the G
−519
-C
−340
haplotype increased MI risk (odds ratio=1.94 [1.15 to 3.28];
P
=0.013). This finding was replicated in a subsequent analysis of 387 Swedish MI patients and 387 healthy controls (odds ratio=0.70 [0.55 to 0.89],
P
=0.003, for A
−519
-C
−340
and G
−519
-T
−340
; odds ratio=1.54 [0.97 to 2.46],
P
=0.07, for G
−519
-C
−340
). In vitro assays showed that compared with the A
−519
-T
−340
haplotype, the A
−519
-C
−340
and G
−519
-T
−340
haplotypes had lower promoter activity, whereas the G
−519
-C
−340
haplotype had greater promoter strength, in driving gene expression in human macrophages. Haplotype-specific differences in MMP1 mRNA level in atherosclerotic tissues were also detected. The data indicate that MMP1 gene variation is a genetic factor contributing to interindividual differences in MI risk.
Short-Term Administration of a New Free Radical Scavenger, Edaravone, Is More Effective Than its Long-Term Administration for the Treatment of Neonatal Hypoxic–Ischemic Encephalopathy
Authors: Noor Jesmin I. , Ikeda Tomoaki , Mishima Kenichi , Aoo Naoya , Ohta Sumie , Egashira Nobuaki , Iwasaki Katsunori , Fujiwara Michihiro , Ikenoue Tsuyomu
Published: October 2005

Background and Purpose—

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a new free radical scavenger that is used for the treatment of adult acute cerebral infarction in Japan. We examined the effect of edaravone on the optimal duration of treatment, the long-term effect on the brain, and the effect on learning and memory disability in a rat model of neonatal hypoxic–ischemic encephalopathy.

Methods—

Seven-day-old Wistar rats were subjected to left common carotid artery ligation then 2 hours of hypoxic–ischemic insult or sham operation. Edaravone was administered intraperitoneally (9 mg/kg) after hypoxic–ischemic insult every 24 hours for 2, 5, or 10 consecutive days. The neuroprotective effect of edaravone was evaluated by behavioral test and histological analysis.

Results—

Two-day treatment with edaravone significantly gave protection to the learning and memory capability, as well as morphological recovery compared with control rats. Five-day treatment showed morphological improvement but no behavioral improvement. In contrast, 10-day treatment did not show either morphological or behavior improvement.

Conclusions—

These findings indicate that edaravone is a promising candidate as a treatment of choice for neonatal hypoxic–ischemic encephalopathy, when its use is limited to the acute phase after hypoxia–ischemia.
In Situ β-Irradiation of a Brain Arteriovenous Malformation Model
Authors: Roy Daniel , Soucy Jean-Paul , Hartman Neil G. , Janicki Christian , Weill Alain , Guilbert François , Papineau Karl , Raymond Jean
Published: October 2005

Background and Purpose—

The treatment of large brain arteriovenous malformations (BAVMs) is challenging, and embolization alone is seldom curative. The study goal is to enhance the efficacy of arteriovenous malformation embolization by adding a β-emitting isotope to the embolic agent.

Methods—

The pig rete mirabile was used as a BAVM model. The body distribution of radioactivity was evaluated after selective rete injection of
N
-butyl,2-cyanoacrylate mixed with
131
I-lipiodol in 8 animals using immediate whole body γ-scintigraphy. Activities within the whole rete mirabile and selected tissue samples were quantified with a gamma counter immediately after sacrifice. Two pigs were submitted to serial γ-scintigraphies for 6 weeks to detect delayed isotope leaching. Long-term effects of in situ irradiation were evaluated using a mixture of
188
Re/
N
-butyl,2-cyanoacrylate in 8 pigs. In 1 animal, autoradiography was performed to evaluate local rete mirabile distribution of the radioactivity. Seven pigs were injected with
188
Re/glue in 1 rete mirabile and with glue only on the opposite side, and the degree of vascular occlusion of both sides was compared on histology at 2 (n=2) or 6 months (n=5).

Results—

There was negligible activity outside the target. Radiation caused occlusion of vessels unreached by the glue itself but in the vicinity of the radioactive source in 5 of 7 rete mirabile.

Conclusions—

Selective deposition of a β-emitter inside a BAVM model may be achieved by current embolization techniques. The adjunct use of an isotope may increase the efficacy of embolization.
Apolipoprotein E Genotype and Incident Ischemic Stroke
Authors: Sturgeon Jared D. , Folsom Aaron R. , Bray Molly S. , Boerwinkle Eric , Ballantyne Christie M.
Published: October 2005

Background and Purpose—

A relationship between the apolipoprotein E (apoE) genotype and ischemic stroke has been inconsistently reported. We explored this relation in the Atherosclerosis Risk in Communities Study (ARIC).

Methods—

The ARIC cohort involves 15 792 men and women, aged 45 to 64 years at baseline and sampled from 4 U.S. communities. Between 1987 and 2001, 498 incident ischemic strokes occurred.

Results—

After stratifying by race and sex and adjusting for other nonlipid risk factors, there was no significant relation between the apoE genotype and incident stroke, except in black women (hazard ratio for ε2 genotype relative to ε3/ε3=0.53; 95% CI, 0.28 to 0.99).

Conclusions—

For the most part, in this middle-aged sample, apoE was not a risk factor for incident ischemic stroke.
Outcome and Severe Hemorrhagic Complications of Intravenous Thrombolysis With Tissue Plasminogen Activator in Very Old (≥80 Years) Stroke Patients
Authors: Berrouschot Jörg , Röther Joachim , Glahn Jörg , Kucinski Thomas , Fiehler Jens , Thomalla Götz
Published: October 2005

Background and Purpose—

Information on safety and efficacy of intravenous thrombolysis with tissue plasminogen activator (tPA) (IV-tPA) in very old acute ischemic stroke (AIS) patients is scarce. We studied outcome and severe hemorrhagic complications in patients aged 80 and older.

Methods—

We analyzed data of AIS patients, treated with IV-tPA, in 3 German stroke centers. Neurologic deficit on admission was assessed using the National Institutes of Health Stroke Scale (NIHSS). Outcome was assessed after 90 days using the Modified Rankin Scale (MRS), and favorable outcome was defined as a MRS score of 0 to 1. Severe intracerebral bleeding complications were assessed on follow-up magnetic resonance imaging or cranial computed tomography. Data were compared between patients <80 years of age and patients aged ≥80 years.

Results—

A total of 228 patients were treated with IV-tPA; 38 (16%) were 80 years or older. There was no difference in NIHSS on admission or onset to treatment time between younger and older patients. Less patients ≥80 years of age achieved a favorable outcome (26.3 versus 46.8%,
P
=0.021), and mortality was higher in older patients (21.1 versus 5.3%,
P
=0.004). There was no difference in the rate of parenchymal hemorrhage (6.3%<80 years versus 5.3%≥80 years,
P
=1.000) and symptomatic intracerebral hemorrhage (2.6%<80 years versus 2.6%≥80 years,
P
=1.000) between both groups.

Conclusion—

There is no increase in severe intracerebral hemorrhage after IV-tPA in very old patients, but outcome is worse as compared with younger patients. There is no evidence to exclude ischemic stroke patients from thrombolysis based on a predefined age threshold.
Gene Transfers of Vascular Endothelial Growth Factor-A, Vascular Endothelial Growth Factor-B, Vascular Endothelial Growth Factor-C, and Vascular Endothelial Growth Factor-D Have No Effects on Atherosclerosis in Hypercholesterolemic Low-Density Lipoprotein-Receptor/Apolipoprotein B48-Deficient Mice
Authors: Leppänen Pia , Koota Suvi , Kholová Ivana , Koponen Jonna , Fieber Christina , Eriksson Ulf , Alitalo Kari , Ylä-Herttuala Seppo
Published: October 2005

Background—

The role of vascular endothelial growth factors (VEGFs) in large arteries has been proposed to be either vasculoprotective or proatherogenic. Because VEGF family members are used for human therapy, it is important to know whether they could enhance atherogenesis. We tested the effects of the members of the VEGF gene family on atherogenesis in LDL-receptor/apolipoprotein (apo) B48 double-knockout (LDLR/apoB48) mice using systemic adenoviral gene transfer.

Methods and Results—

Six groups of LDLR/apoB48-deficient mice (n=110) were kept 3 months on a Western-type diet. After 6 weeks of diet, mice were injected via tail vein with recombinant adenoviruses expressing VEGF-A, -B, -C, or -D or LacZ (1×10
9
PFU) or rhVEGF-A protein (2 μg/kg) and euthanized 6 weeks later. Also, older mice (n=36) were injected after 4 months on the diet and euthanized 6 weeks later (total time on the diet, 22 weeks) to evaluate the effects of gene transfers on the development of more mature lesions. Aortas were analyzed for the presence of macroscopic lesions, cross-sectional lesion areas, neovascularization, and cellular composition of the lesions. All groups had equivalent plasma cholesterol and triglyceride levels. Gene transfers with recombinant adenoviruses or administration of rhVEGF-A protein had no statistically significant effects on en face atherosclerotic lesions in the aorta, cross-sectional lesion area, neovascularization, or cellular composition of the lesions.

Conclusions—

This study shows no proatherogenic effects of adenovirus-mediated gene transfers of VEGF-A, -B, -C, or -D in the LDLR/apoB48-deficient hypercholesterolemic mice, in which lipoprotein profile and atherosclerosis closely resemble those in human disease.
Long-Term Effects of Ramipril on Cardiovascular Events and on Diabetes
Authors:   HOPE/HOPE-TOO Study Investigators
Published: October 2005

Background—

We have previously demonstrated that ramipril reduces vascular events and new diagnoses of diabetes when given for a 4.5-year period. However, it is not known whether the benefits are observed in subgroups of patients at varying risk or on other proven therapies and whether the benefits are sustained beyond the current trial. The 2 aims of this investigation were to assess whether the benefits observed during the HOPE trial were (1) maintained after trial cessation during an additional 2.6 years of follow-up and (2) observed in subgroups based on risk and ancillary treatments.

Methods and Results—

Of the initial 267 study centers and 9297 patients, 174 centers and 4528 patients agreed to further follow-up. The rates of use of angiotensin-converting-enzyme inhibitors (ACEIs) in the 2 groups (72% ramipril versus 68% placebo) were similar after the end of the trial. During the posttrial follow-up, patients allocated to ramipril had a 19% further lower relative risk (RR) of myocardial infarction (95% confidence interval [CI], 0.65 to 1.01), a 16% lower RR (95% CI, 0.70 to 0.99) of revascularization, and a 34% lower RR of a new diagnosis of diabetes (95% CI, 0.46 to 0.95). Similar RR reductions in vascular events were observed during and after the active phase of the trial, regardless of baseline risk (RR of 0.76, 0.89, and 0.83 for low-, medium-, and high-risk patients, respectively) or ancillary treatments (RR of 0.90 for aspirin, 0.76 for β-blockers, and 0.84 for lipid-lowering medication).

Conclusions—

The benefits of ramipril observed during the active period of the HOPE trial were maintained during posttrial follow-up for cardiovascular death, stroke, and hospitalization for heart failure. Additional reductions in myocardial infarction, revascularization, and the development of diabetes were observed during the follow-up phase despite similar rates of ACEI use in the 2 randomized groups. These benefits were consistent regardless of patient risk or ancillary treatments.
T-cell non-Hodgkin lymphoma
Authors: Rizvi Mujahid A. , Evens Andrew M. , Tallman Martin S. , Nelson Beverly P. , Rosen Steven T.
Published: October 2005

T-cell non-Hodgkin lymphomas (NHLs) are uncommon malignancies. The current WHO/EORTC classification recognizes 9 distinct clinicopathologic peripheral T-cell NHLs. These disorders have unique characteristics and require individualized diagnostic and therapeutic strategies. Tremendous progress has been made in recent years in the understanding of the pathogenesis of these disorders. Specific chromosomal translocations and viral infections are now known to be associated with certain lymphomas. In this review, we describe their clinical and pathologic features. We also discuss the use of molecular studies in the diagnostic work-up of T-cell lymphomas. Because of the rarity of these disorders and the lack of well-designed clinical trials, the treatment of peripheral T-cell NHLs is often challenging. Additional studies are required to learn more about the biology of these diseases, which may lead to more optimal and possibly targeted therapies.
Sequential activation of p38 and ERK pathways by cGMP-dependent protein kinase leading to activation of the platelet integrin αIIbβ3
Authors: Li Zhenyu , Zhang Guoying , Feil Robert , Han Jiahuai , Du Xiaoping
Published: October 2005

Integrin activation (inside-out signaling) in platelets can be initiated by agonists such as von Willebrand factor (VWF) and thrombin. Here we show that a mitogen-activated protein kinase (MAPK), p38, plays an important role in the activation of integrin αIIbβ3 induced by VWF and thrombin. A dominant-negative mutant of p38, p38AF, inhibits αIIbβ3 activation induced by VWF binding to its receptor, the platelet glycoprotein Ib-IX (GPIb-IX), and p38 inhibitors diminish platelet aggregation induced by VWF or low-dose thrombin. The inhibitory effect of p38 inhibitor is unlikely to be caused by the previous suggested effect on cyclo-oxygenase, as inhibition also was observed in the presence of high concentrations of cyclo-oxygenase inhibitor, aspirin. VWF or thrombin induces p38 activation, which is inhibited in cGMP-dependent protein kinase (PKG)-knockout mouse platelets and PKG inhibitor-treated human platelets, indicating that activation of p38 is downstream from PKG in the signaling pathway. p38AF or p38 inhibitors diminish PKG-induced phosphorylation of extracellular stimuli-responsive kinase (ERK), which also is important in integrin activation. Thus, p38 plays an important role in mediating PKG-dependent activation of ERK. These data delineate a novel signaling pathway in which platelet agonists sequentially activate PKG, p38, and ERK pathways leading to integrin activation.
Late Quaternary loss of genetic diversity in muskox (Ovibos)
Authors: MacPhee Ross DE , Tikhonov Alexei N , Mol Dick , Greenwood Alex D
Published: October 2005

Background

The modern wildherd of the tundra muskox (Ovibos moschatus) is native only to the New World (northern North America and Greenland), and its genetic diversity is notably low. However, like several other megafaunal mammals, muskoxen enjoyed a holarctic distribution during the late Pleistocene. To investigate whether collapse in range and loss of diversity might be correlated, we collected mitochondrial sequence data (hypervariable region and cytochrome b) from muskox fossil material recovered from localities in northeastern Asia and the Arctic Archipelago of northern North America, dating from late Pleistocene to late Holocene, and compared our results to existing databases for modern muskoxen.

Results

Two classes of haplotypes were detected in the fossil material. "Surviving haplotypes" (SHs), closely similar or identical to haplotypes found in modern muskoxen and ranging in age from ~22,000 to ~160 yrbp, were found in all New World samples as well as some samples from northeastern Asia. "Extinct haplotypes" (EHs), dating between ~44,000 and ~18,000 yrbp, were found only in material from the Taimyr Peninsula and New Siberian Islands in northeastern Asia. EHs were not found in the Holocene muskoxen specimens available for this study, nor have they been found in other studies of extant muskox populations.

Conclusion

We provisionally interpret this evidence as showing that genetic variability was reduced in muskoxen after the Last Glacial Maximum but before the mid-Holocene, or roughly within the interval 18,000-4,000 yrbp. Narrowing this gap further will require the recovery of more fossils and additional genetic information from this interval.
Heterotachy and long-branch attraction in phylogenetics
Authors: Philippe Hervé , Zhou Yan , Brinkmann Henner , Rodrigue Nicolas , Delsuc Frédéric
Published: October 2005

Background

Probabilistic methods have progressively supplanted the Maximum Parsimony (MP) method for inferring phylogenetic trees. One of the major reasons for this shift was that MP is much more sensitive to the Long Branch Attraction (LBA) artefact than is Maximum Likelihood (ML). However, recent work by Kolaczkowski and Thornton suggested, on the basis of simulations, that MP is less sensitive than ML to tree reconstruction artefacts generated by heterotachy, a phenomenon that corresponds to shifts in site-specific evolutionary rates over time. These results led these authors to recommend that the results of ML and MP analyses should be both reported and interpreted with the same caution. This specific conclusion revived the debate on the choice of the most accurate phylogenetic method for analysing real data in which various types of heterogeneities occur. However, variation of evolutionary rates across species was not explicitly incorporated in the original study of Kolaczkowski and Thornton, and in most of the subsequent heterotachous simulations published to date, where all terminal branch lengths were kept equal, an assumption that is biologically unrealistic.

Results

In this report, we performed more realistic simulations to evaluate the relative performance of MP and ML methods when two kinds of heterogeneities are considered: (i) within-site rate variation (heterotachy), and (ii) rate variation across lineages. Using a similar protocol as Kolaczkowski and Thornton to generate heterotachous datasets, we found that heterotachy, which constitutes a serious violation of existing models, decreases the accuracy of ML whatever the level of rate variation across lineages. In contrast, the accuracy of MP can either increase or decrease when the level of heterotachy increases, depending on the relative branch lengths. This result demonstrates that MP is not insensitive to heterotachy, contrary to the report of Kolaczkowski and Thornton. Finally, in the case of LBA (i.e. when two non-sister lineages evolved faster than the others), ML outperforms MP over a wide range of conditions, except for unrealistic levels of heterotachy.

Conclusion

For realistic combinations of both heterotachy and variation of evolutionary rates across lineages, ML is always more accurate than MP. Therefore, ML should be preferred over MP for analysing real data, all the more so since parametric methods also allow one to handle other types of biological heterogeneities much better, such as among sites rate variation. The confounding effects of heterotachy on tree reconstruction methods do exist, but can be eschewed by the development of mixture models in a probabilistic framework, as proposed by Kolaczkowski and Thornton themselves.