bluuebunny/crossref_metadata_2025_split huggingface dataset:
5'-3' Interactions in regulation of translation in Xenopus early embryos
Authors: Browder Leon W , Wilkes-Johnston Jillian , Fraser Sherri D 
Published: April 2011

We have investigated the effects of 3' noncoding elements in enhancing translation of messengers having translation-inhibiting 5' untranslated regions (UTRs). The translation of transcripts bearing the 5' UTRs of either human c-myc or a synthetic hairpin structure upstream of a chloramphenicol acetyltransferase (CAT) reporter sequence is greatly attenuated in early embryos of Xenopus laevis. Translation of transcripts bearing the human c-myc-5' UTR was markedly stimulated by the presence of 3' poly(A). Transcripts bearing the 5' hairpin element were insensitive to the presence of poly(A), but they were extremely sensitive to the composition of the 3' UTR. A GC-rich distal sequence repressed translation, whereas a proximal GGAAU sequence promoted translation of these transcripts. Our results support the concept that long-range interactions between the 5' and 3' ends of transcripts are important in regulating translation in Xenopus embryos. Key words: translational regulation, oncogenes, c-myc, Xenopus laevis, development, embryo.
Effect of fines content on frost heave
Authors: Tester Robert E , Gaskin Paul N 
Published: April 2011

In regions of seasonal frost the integrity of pavement structures is dependent on the resistance of base and subbase soils to frost action. This note describes the results of performing the U.S. Army Cold Regions Research and Engineering Laboratory CRREL II laboratory freezing test on a crushed limestone with a varying fines content. Frost heave increased linearly as fines content increased. Under the CRREL frost susceptibility criterion, the crushed gravel was satisfactory with up to 8% fines. A greater fines content resulted in an unsatisfactory classification. Key words: frost susceptibility, fines content, road base.
A kinetic modeling study of ethylene pyrolysis
Authors: Roscoe John M , Bossard Alain R , Back Margaret H 
Published: April 2011

A kinetic model is presented for the pyrolysis of ethylene at pressures ranging from 0.8 to 27 kPa and temperatures from 774 to 1023 K. The model is based on experimental measurements of C2H2, C2H6, C3H6, 1-C4H8, and 1,3-C4H6. In this temperature range the reaction is initiated by the disproportionation of C2H4 and the observed products result from reactions of the C2H3 and C2H5 radicals produced in this process. The C2H2 and 1,3-C4H6 result from reactions of C2H3 while C2H6, C3H6, and 1-C4H8 result from reactions of C2H5. C2H2 is produced exclusively by the decomposition of the C2H3 radical. This process is in its falloff region throughout the range of experimental conditions examined and the yield of C2H2 provides a measure of the degree of falloff. The production of 1,3-C4H6 is controlled by the reaction C4H7 –> C4H6 + H. The rate constants for this reaction were independent of pressure and are given as a function of temperature by k = 2.2 × 1013 exp (-19.6 × 103/T). Production of C2H6 is controlled by the reaction C2H5 + C2H4 –> C2H6 + C2H3. The rate constant for this reaction is given as a function of temperature by k = 5.83 × 1011 exp (-14.6 × 103/T). C3H6 is produced by decomposition of 2-C4H9 and is controlled kinetically by the isomerization reaction 1-C4H9 –> 2-C4H9. The temperature dependence of the rate constants obtained for this reaction leads to a preexponential factor of approximately 3 × 1016 and an activation energy of approximately 200 kJ mol-1. The yield of 1-C4H8 is controlled by 1-C4H9 –> 1-C4H8 + H. The rate constants for this reaction were independent of pressure and are given as a function of temperature by k = 2.97 × 1012 exp (-17.1 × 103/T). Key words: kinetic modeling, ethylene pyrolysis.
Weight Gain after Tonsillectomy
Authors: Wei Julie L. 
Published: April 2011

Excessive weight gain after tonsillectomy has been described by a handful of studies since as early as 1988 and, in recent years, mostly with variable study design, methods, and baseline weight of the subjects. Although most otolaryngologists have likely been asked whether tonsillectomy may lead to weight gain by parents and caretakers, there has been very limited research on this issue, and certainly no causal effect has been established by existing research. Awareness and counseling based on what has been described are relevant as a part of preoperative counseling. However, it is critical that our national epidemic of excessive weight gain in children and adolescents not be simply reduced to a matter of tonsillectomy but be understood as a multifactorial and complex issue. To study this topic well requires commitment to well‐designed studies assessing caloric intake and expenditure, metabolic changes, and prospective growth measurements. Mechanisms for weight gain, even if excessive during the 12 months after tonsillectomy surgery, are far from being elucidated.
Smad1 signaling restricts hematopoietic potential after promoting hemangioblast commitment
Authors: Cook Brandoch D. , Liu Susanna , Evans Todd 
Published: April 2011

AbstractBone morphogenetic protein (BMP) signaling regulates embryonic hematopoiesis via receptor-mediated activation of downstream SMAD proteins, including SMAD1. In previous work, we showed that Smad1 expression is sufficient to enhance commitment of mesoderm to hemangioblast fate. We also found indirect evidence to support a subsequent repressive function for Smad1 in hematopoiesis. To test this hypothesis directly, we developed a novel system allowing temporal control of Smad1 levels by conditional knockdown in embryonic stem cell derivatives. Depletion of Smad1 in embryoid body cultures before hemangioblast commitment limits hematopoietic potential because of a block in mesoderm development. Conversely, when Smad1 is depleted in FlK1+ mesoderm, at a stage after hemangioblast commitment, the pool of hematopoietic progenitors is expanded. This involves enhanced expression levels for genes specific to hematopoiesis, including Gata1, Runx1 and Eklf, rather than factors required for earlier specification of the hemangioblast. The phenotype correlates with increased nuclear SMAD2 activity, indicating molecular cross-regulation between the BMP and TGF-β signaling pathways. Consistent with this mechanism, hematopoiesis was enhanced when Smad2 was directly expressed during this same developmental window. Therefore, this study reveals a temporally defined function for Smad1 in restricting the expansion of early hematopoietic progenitors.
HBx Sensitizes Cells to Oxidative Stress-induced Apoptosis by Accelerating the Loss of Mcl-1 Protein via Caspase-3 Cascade
Authors: Hu Liang , Chen Lei , Yang GuangZhen , Li Liang , Sun HanYong , Chang YanXin , Tu QianQian , Wu MengChao , Wang HongYang 
Published: April 2011

Abstract

Background
Oxidative stress has been implicated in the pathogenesis of a wide spectrum of human diseases, including Hepatitis B virus (HBV)-related liver disease. Hepatitis B virus X protein (HBx) is a key regulator of HBV that exerts pleiotropic activity on cellular functions. Recent studies showed that HBx alters mitochondrial membrane potential, thereby sensitizing cells to pro-apoptotic signals. However, it remains largely unknown whether susceptibility of hepatocytes could be disturbed by HBx under oxidative stress conditions. The purpose of this study is to determine the apoptotic susceptibility of HBx-expressing hepatocytes upon exposure to pro-oxidant stimuli in vitro and in vivo and explore its underlying mechanism.

Results
Although expression of HBx itself did not activate apoptotic signaling, it significantly enhanced oxidative stress-induced cell death both in vitro and in vivo. Interestingly, this phenomenon was associated with a pronounced reduction of protein levels of Mcl-1, but not other anti-apoptotic Bcl-2 members. Importantly, enforced expression of Mcl-1 prevented HBx-triggered cell apoptosis; conversely, specific knockdown of Mcl-1 exacerbated HBx-induced apoptosis upon exposure to oxidative stress. Furthermore, inhibition of caspase-3 not only abrogated HBx-triggered apoptotic killing but also blocked HBx-induced Mcl-1 loss. Additionally, expression of HBx and Mcl-1 was found to be inversely correlated in HBV-related hepatocellular carcinogenesis (HCC) tissues.

Conclusions
Our findings indicate that HBx exerts pro-apoptotic effect upon exposure to oxidative stress probably through accelerating the loss of Mcl-1 protein via caspase-3 cascade, which may shed a new light on the molecular mechanism of HBV-related hepatocarcinogenesis.
Luxury Perfusion Syndrome Confirmed by Sequential Studies of Regional Cerebral Blood Flow and Volume after Extracranial to Intracranial Bypass Surgery: Case Report
Authors: Higashi Sotaro , Matsuda Hiroshi , Fujii Hiroyuki , Ito Haruhide , Yamashita Junkoh 
Published: April 2011

Abstract
We report a case of luxury perfusion syndrome with temporary neurological deterioration after extracranial to intracranial bypass surgery. A preoperative computed tomographic scan showed no detectable infarct, and the measurement of regional cerebral blood flow showed severe depression of ipsilateral hemispheric perfusion. The patient developed temporary neurological deterioration after bypass surgery, with no recognizable pathological signs on postoperative computed tomographic and angiographic studies. Regional cerebral blood flow and volume were more elevated during the period of neurological deterioration than after the subsequent recovery. This strongly suggests that excessive blood flow directed into chronically ischemic brain through a graft may induce a luxury perfusion syndrome resulting in neurological deterioration.
The Incidence of Unexpected Pathological Findings in an Image-Guided Biopsy Series: A Review of 100 Consecutive Cases
Authors: Friedman William A. , Sceats James D. , Nestok Blake R. , Ballinger William E. 
Published: April 2011

Abstract
Despite the widespread availability of image-guided stereotactic biopsy, the need for such procedures in patients with “clear-cut” clinical and radiographic diagnoses is still frequently discussed. In an attempt to ascertain the incidence of unexpected pathological findings, 100 consecutive stereotactic biopsies have been reviewed. Twelve patients were found to have diagnoses of pathological conditions that preoperatively were considered unlikely, or not considered at all. The details of these “diagnostically discordant” cases are discussed.
Cerebral Distribution of Immunoconjugate after Treatment for Neoplastic Meningitis Using an Intrathecal Radiolabeled Monoclonal Antibody
Authors: Benjamin Jonathan Charles , Moss Timothy , Mosely Robin Peter , Maxwell Ruth , Coakham Hugh Beresford 
Published: April 2011

Abstract
A detailed autopsy and autoradiographic study was performed after the death of a patient undergoing intrathecal, antibody-guided irradiation for carcinomatous meningitis. The results demonstrated tumor cells infiltrating the surface meninges and a severe astrocytic reaction associated with oedema in the periventricular and brain stem subpial white matter. This was not seen in cortical or other gray matter structures. Autoradiographic examination correlated well, demonstrating isotope within the oedematous areas of the white matter in addition to the expected concentration in the leptomeningeal layers. These findings are discussed in the context of antibody binding to tumor tissue and the possible benefits conferred in the treatment of infiltrating tumor cells.
Brown-Seéquard Syndrome Associated with Posttraumatic Cervical Epidural Hematoma: Case Report and Review of the Literature
Authors: Zupruk Gerald M. , Mehta Zoya 
Published: April 2011

Abstract
Post-traumatic cervical epidural hematoma is an uncommon entity. A case is presented in which such a lesion developed after chiropractic manipulation of the neck. The patient presented with a Brown-Séquard syndrome, which has only rarely been reported in association with cervical epidural hematoma. The correct diagnosis was obtained by computed tomographic scanning. Surgical evacuation of the hematoma was followed by full recovery.
Transcranial Doppler Monitoring of Cerebral Flow Velocities during Surgical Occlusion of the Carotid Artery
Authors: Powers Alexandros D. , Smith Robert R. , Graeber Michael C. 
Published: April 2011

Abstract
Transcranial Doppler (TCD) was used to assess collateral flow and to quantitate perfusion velocity changes in a group of 18 patients requiring temporary or permanent surgical occlusion of the internal carotid artery for treatment of their cerebrovascular lesions. Velocity measurements were correlated with times of occlusion and neurological outcome in order to assess safe vessel occlusion times and the need for an intraoperative shunt. These data were used to calculate a perfusion velocity index (PVi), which indicated that values &gt;2 were well tolerated, and values of &lt;1 were associated with ischemic signs. In addition, preoperative TCD examinations were combined with compressive maneuvers of the carotid artery in the neck to evaluate the feasibility of carotid clamp ligation for the treatment of giant intracranial aneurysms deemed unsuitable for direct clipping. When maintenance of neurological function and intracranial vessel flow velocities were found to be normal, with aneurysmal flow velocities of zero, ligation of the carotid artery could safely be undertaken. Finally, TCD allowed continuous surveillance of cerebral hemodynamics, which gave immediate assurance of postoperative ICA patency, as well as the ability to identify high velocity states associated with hyperperfusion syndromes, which occurred in two patients.
Late Magnetic Resonance Imaging Related to Neurobehavioral Functioning after Aneurysmal Subarachnoid Hemorrhage
Authors: Romner Bertil , Sonesson Bengt , Ljunggren Bengt , Brandt Lennart , Säveland Hans , Holtås Stig 
Published: April 2011

Abstract
Twenty patients who underwent early aneurysm surgery—that is, surgery within 72 hours after rupture—underwent further follow-up examination including magnetic resonance imaging (MRI) of the brain and a comprehensive neuropsychological assessment. Significant statistical correlation between tissue loss as seen on a late MRI scan and neurobehavioral deficits could not be established. Among 9 patients with no tissue loss seen on MRI, 3 exhibited substantial cognitive dysfunction and 6 had mild impairment. Three patients showed minor but corresponding tissue loss and deficits. In 3 patients with pronounced pathological indications on MRI, evidence of cognitive dysfunction was absent in 2, and 1 patient showed substantial impairment. The remaining 5 individuals displayed moderate pathological indications on MRI, with no obvious correspondence to cognitive functioning. In 7 patients, small white matter lesions, probably silent infarcts not seen on computed tomographic scan, were discovered on MRI. There was a clear relationship between arterial hypertension prior to aneurysm rupture and the extent of tissue loss seen on MRI. Absence of pathological findings on MRI scan did not exclude cognitive malfunctioning, and vice-versa.
Transluminal Angioplasty of Intracerebral Vessels for Cerebral Arterial Spasm: Reversal of Neurological Deficits after Delayed Treatment
Authors: Barnwell Stanley L. , Higashida Randall T. , Halbach Van V. , Dowd Christopher F. , Wilson Charles B. , Hieshima Grant B. 
Published: April 2011

Abstract
We used intracerebral transluminal angioplasty to treat two episodes of symptomatic vasospasm in a patient recovering from an aneurysmal subarachnoid hemorrhage. The procedures were performed after medical therapies, intravascular volume expansion, and induced arterial hypertension failed to alleviate the patient's neurological condition. The first angioplasty, confined to the right middle cerebral and distal internal carotid arteries, took place more than 30 hours after the onset of left hemiplegia. Despite the subsequent discovery of a small parietal lobe infarct, it brought about a marked improvement in left motor function and may have also limited the spread of necrotic damage. The second angioplasty was necessitated when stenotic segments of the basilar and posterior cerebral arteries caused a 24-hour decline in the patient's mental status. Although delayed in relation to the onset of symptoms, it successfully reversed the patient's comatose state. The use of transluminal angioplasty for vasospasm is generally limited to cases where it can be performed shortly after the onset of neurological symptoms; delaying the procedure increases the risk of hemorrhage from reperfused areas of infarction. Our experience with this patient demonstrates that delayed angioplasty can improve vascular flow to ischemic territory, even after infarction, without complications and with resultant improvement in neurological function.
Suprasellar Arachnoid Cysts: Management by Cyst Wall Resection
Authors: Jones Robert Francis Clifford , Warnock Timothy Hugh , Nayanar Vimala , Gupta Jagdish Mitter 
Published: April 2011

Abstract
Five children with ventricular dilatation (4 boys, 1 girl) had features seen on computer tomographic scan that were consistent with suprasellar arachnoid cysts. All children were investigated with a CT ventriculogram and/or CT cisternogram, and no communication with the cyst was demonstrated. Three children were seen in the 1st year of life and the remaining 2 children were between 1 and 5 years of age. Hydrocephalus and developmental delay were the most common presenting features, followed by visual disturbance, squint, or ataxia. Direct surgical decompression was performed in all 5 patients to avoid long-term placement of a ventriculoperitoneal shunt. A temporary shunt was placed in 2 children because of high intracranial pressure. Direct partial excision of the cyst wall to allow long-term drainage into the basal cisterns or ventricular system was successful in all children. The presence of subdural collections postoperatively required temporary shunting in 2 children. After follow-up for between 10 and 22 months no clinical endocrinological sequelae have been detected, but 2 children have raised serum prolactin levels. Three children are developmentally delayed; one of these has regained some skills since surgery. Direct surgical decompression of suprasellar arachnoid cysts to avoid long-term shunt placement is the preferred method of surgical treatment for this condition.
Efficacy of Single Intracisternal Bolus Injection of Recombinant Tissue Plasminogen Activator to Prevent Delayed Cerebral Vasospasm after Experimental Subarachnoid Hemorrhage
Authors: Seifert Volker , Eisert Wolfgang G. , Stolke Dietmar , Goetz Christoph 
Published: April 2011

Abstract
Premature lysis of subarachnoid blood clots by thrombolytic substances such as urokinase and plasmin has been shown to be efficacious in preventing cerebral vasospasm in clinical and experimental investigations. Recently, tissue plasminogen activator (rtPA) derived from recombinant deoxyribonucleic (DNA) technology has been introduced as a new thrombolytic substance. With its high affinity for fibrin-bound plasminogen and low affinity for circulating plasminogen by which a clot-selective fibrinolysis can be achieved without the danger of inducing systemic fibrinogenolysis, rtPA might be the ideal substance for the postoperative lysis of cisternal blood accumulations after subarachnoid hemorrhage. The efficacy of rtPA in preventing delayed cerebral vasospasm after experimental subarachnoid hemorrhage using a single intracisternal bolus injection of this agent was investigated. With a single injection of 25 Mg of rtPA into the cisterna magna 48 hours after the first and 6 hours after the second injection of blood in the two-hemorrhage model of cerebral vasospasm, angiographic spasm of the basilar artery was completely prevented in all animals so treated whereas in the control group severe vasospasm occurred. Autopsy studies of the experimental animals demonstrated that the subarachnoid blood clots were almost completely removed by intracisternal rtPA application. Additionally the pathomorphological signs of proliferative vasculopathy present in all animals of the control group were not demonstrable in the rtPA group. As intracisternal bolus injection of rtPA is highly efficacious in preventing angiographic as well as pathomorphological vasospasm, it is concluded that use of this thrombolytic substance might be a promising approach for pharmacological blood clot removal.
The Effects of Hyperventilation on Cerebral Blood Flow in the Rat with an Open and Closed Carotid-Jugular Fistula
Authors: Morgan Michael K. , Anderson Robert E. , Sundt Thoralf M. 
Published: April 2011

Abstract
Perturbations in cerebral hemodynamics at the time of ablation of an arteriovenous shunt have been regarded as important in the pathogenesis of swelling and hemorrhage complicating resection of arteriovenous malformations (AVMs). A carotid-jugular fistula model in the rat had previously been investigated and found to simulate in part the nonhemorrhagic pathophysiology of a large cerebral arteriovenous fistula. Utilizing this model and measuring cerebral blood flow in 14 regions with a [14C]iodoantipyrine autoradiographic technique, the effects of hypocapnea on the cerebral circulation in opened and closed fistulas were investigated. Regional cerebral blood flow (rCBF) in control animals ranged from a median of 53 to 64 ml/100 g/min at a partial arterial carbon dioxide pressure (PaCO2) of 28 ± 2 mm Hg and 85 to 112 ml/100 g/min at a PaCO2 of 40 ± 5 mm Hg. In animals with an open carotid-jugular fistula created 12 weeks before the study, these median rCBF values at comparable PaCO2 levels ranged, respectively, from 15 to 39 ml/100 g/min and 50 to 68 ml/100 g/min (the 25th percentile for the open fistula in the hypocapneic group was 15 ml/100 g/min in 5 of the 14 regions studied). In contrast, median rCBF in the closed fistula group ranged from 73 to 100 ml/100 g/min in hypocapneic animals and from 118 to 187 ml/100 g/min in normocapneic animals. These results demonstrate the preservation of CO2 reactivity; hypoperfusion in the presence of a carotid-jugular fistula, hyperemia on fistula occlusion, and the potential to induce cerebral ischemia with hyperventilation in this model of a cerebral arteriovenous fistula. These data caution against the use of hyperventilation during surgery in patients with cerebral arteriovenous malformations.
Transcranial Doppler Monitoring of Cerebral Blood Velocity During Craniotomy
Authors: Giller Cole A. 
Published: April 2011

Abstract
Transcranial Doppler techniques were used to monitor blood velocity in cerebral arteries continuously during 14 neurosurgical operations performed on 13 patients, including 12 craniotomies. Stable Doppler signals were obtained for prolonged periods of time, and they correlated with intraoperative events. Monitoring during spontaneous blood pressure and CO2 variations allowed assessment of autoregulatory capacity. In particular, 5 of the 7 patients receiving craniotomy for aneurysmal subarachnoid hemorrhage had impaired autoregulation. A 30 to 50% decrease in Doppler velocities was seen in 7 patients after etomidate administration. Early experience suggests that transcranial Doppler monitoring during craniotomy is feasible and can indicate the effects of operative events on blood flow as well as provide an assessment of cerebral autoregulation.