bluuebunny/crossref_metadata_2025 huggingface dataset:
Contributions of the lower crust to Mesozoic mantle-derived mafic rocks from the North China Craton: implications for lithospheric thinning
Authors: Huang F. , Li S.-G. , Yang W.
Published: November 2007

The lithospheric mantle underneath the North China Craton changed completely from the Palaeozoic to the Cenozoic. This study reviews geochemical data from Mesozoic mantle-derived mafic rocks from the North China Craton to investigate the role of mafic lower continental crust in lithosphere replacement. Samples from the North China Craton have typical ‘continental’ geochemical signatures, including depletion of high field strength elements, enrichment of large ion lithophile elements and Pb, unradiogenic Pb isotopes, and enriched Sr–Nd isotopic ratios. Positive correlation between initial
87
Sr/
86
Sr and
206
Pb/
204
Pb, low Ce/Pb and Nb/U, high Ba/Nb and La/Nb, and unradiogenic Pb isotopes of Mesozoic mafic rocks cannot simply be explained by derivation from a lithospheric mantle enriched by ancient (Archaean or Mesoproterozoic) fluid or melt metasomatism. Instead, they more probably result from a lithospheric mantle or upwelling asthenosphere underneath the North China Craton that was modified by the lower continental crust in the Mesozoic. Because oceanic plate subduction zones surrounded the North China Craton during the late Palaeozoic, the lithospheric mantle underneath the North China Craton was weakened by fluids derived from subducted slabs, and thus shortened and thickened by continent–continent collisions of the North China Block with the South China Block and the Siberian plate. Metamorphic reactions occurred in the mafic lower continental crust beneath the North China Craton, creating garnet-bearing assemblages (eclogite and garnet pyroxenite) with densities of up to 3.8 g cm
−3
, which led to negative buoyancy in the over-thickened lithosphere. The unstable lithosphere was delaminated and subsided into the uppermost mantle. The delaminated lower crust partially melted, producing SiO
2
-rich melts that metasomatized surrounding asthenospheric mantle, which upwelled and replaced the volume formerly occupied by the delaminated lithospheric mantle, resulting in the ‘continental’ geochemical signatures widely observed in Mesozoic mantle-derived mafic rocks from the North China Craton. The ‘continental’ geochemical signatures of Mesozoic mantle-derived mafic rocks suggest that lithospheric delamination could have occurred by the time of volcanic eruption in the northern margin of the North China Craton in the mid-Jurassic and later in the southern margin and Dabie–Sulu Orogen in the early Cretaceous.
Late Mesozoic mafic magmatism from the North China Block: constraints on chemical and isotopic heterogeneity of the subcontinental lithospheric mantle
Authors: Fan W. , Guo F. , Wang Y. , Zhang H.
Published: November 2007

Available major, trace element and Sr–Nd isotope data for the late Mesozoic mafic rocks in the eastern North China Block (NCB) show chemical and isotopic differences between rocks from different tectonic units. Such differences are interpreted as signatures inherited from the melted mantle sources, which had experienced distinctive enrichment processes during lithospheric evolution. The subcontinental lithospheric mantle beneath the NCB interior is characterized by long-term light REE (LREE) enrichment and EM1-like Sr–Nd isotopic signatures. Such a lithospheric mantle is mainly composed of chemically refractory peridotites that are common in cratonic regions. In contrast to that of the NCB interior, beneath the northern part of the NCB a relatively chemically fertile mantle was enriched in large ion lithophile elements and LREE and depleted in Nb–Ta and Th–U. It has higher
87
Sr/
86
Sr(i) and ε
Nd
(
t
) than that of the interior of the block, and is interpreted to have been modified by recycled lower continental crust components related to the palaeo-Asian Ocean subduction. The lithospheric mantle beneath the southern NCB has the highest
87
Sr/
86
Sr(i) and the lowest ε
Nd
(
t
), and is chemically transitional between the interior and northern part of the block. Formation of such an enriched lithospheric mantle was closely associated with modification from the subducted Yangtze lower–middle crust during Triassic collision between the North China and Yangtze Blocks. A lithospheric extension–thinning model is proposed to explain the petrogenesis of these late Mesozoic mafic rocks in the eastern North China Block. This process was amplified by effects from surrounding plate interactions, including the rapid northward movement of the palaeo-Pacific Ocean, compressional forces from the Siberian plate, the Tethyan tectonic belt and possibly the Indo-China Block. The resultant forces triggered lithospheric extension, asthenospheric upwelling, and decompressional melting of the enriched mantle sources.
Polyphase Mesozoic tectonics in the eastern part of the North China Block: insights from the eastern Liaoning Peninsula massif (NE China)
Authors: Lin W. , Faure M. , Monié P. , Wang Q.-C.
Published: November 2007

In Eastern China, the North China Block (NCB) has experienced a complex tectonic evolution during Late Palaeozoic to Mesozoic times. The unconformable sedimentary cover, which ranges in age from Neoproterozoic to Permian, underwent two tectonic episodes in Early Triassic and Cretaceous times. An early north–south compressional phase, D
1
, characterized by north-verging recumbent folds with east–west-trending axes and top-to-the-north ductile shear zones can be observed in a gabbroic pluton and the Neoproterozoic sedimentary host rocks. The available radiometric ages allow us to interpret this event as an Early Triassic back-thrusting related to the final stage of the collision between the North China and South China Blocks. During the Late Mesozoic, an extensional event characterized by (1) half-grabens filled by continental terrigeneous red beds and lava flows, (2) low-angle detachment faults, (3) synkinematic granitic plutons, and (4) metamorphic core complexes is widespread in the Eastern Liaoning Peninsula. This extensional D
2
event can be subdivided into a ductile deformation and a brittle deformation, corresponding to different expressions of crustal deformation. In every area studied in the Eastern Liaoning Peninsula, the ductile D
2
deformation is characterized by a NW–SE-trending stretching lineation with a top-to-the-NW sense of shear. Mica and amphibole from the metamorphic country rocks, granodioritic or monzogranitic plutons and their mylonitized margins yield
40
Ar/
39
Ar ages ranging from 130 to 120 Ma. These dates support fast cooling and exhumation rates coeval with the extensional tectonics. The brittle D
2
deformation is responsible for the formation of high-angle normal faults marked by low-temperature cataclasites bounding half-grabens. During the Mesozoic, the tectonic regime of Eastern China experienced a significant inversion from compression to extension. The Eastern Liaoning Peninsula massif provides an example of this geodynamic transition.
Mesozoic tectonics in the Eastern Block of the North China Craton: implications for subduction of the Pacific plate beneath the Eurasian plate
Authors: Li S. Z. , Kusky T. M. , Zhao G. , Wu F. , Liu J.-Z. , Sun M. , Wang L.
Published: November 2007

The Jiao-Liao massif is located in the hanging wall of the north-dipping Dabie–Sulu suture zone and is an important part of the Eastern Block of the North China Craton. Several important tectonic models for the tectonic evolution of Eastern Asia rely on critical information from the Jiao-Liao massif. This paper combines new sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon ages of the Dandong Granite in the southern Liaoning Province, China, with extensive field data for the eastern North China Craton, including the Bohai Bay Basin. Combined with other recent SHRIMP dating, we use this information to summarize the Mesozoic tectonic reactivation and evolutionary processes of the Jiao-Liao massif of the Eastern Block of the North China Craton. In this study we identify a
c
. 160 Ma episode of partial melting of Palaeoproterozoic plutons in the Jiao-Liao massif. Cathode luminescence and backscatter electron imagery reveal
c
. 167–157 Ma magmatic euhedral single zircons and magmatic zircon rims surrounding
c
. 2100 Ma cores in the Dandong Granites near the Liaonan Neoarchaean terrane. This partial melting is probably related to
in situ
remelting of ancient lower continental material, mostly the North China Craton. The Dandong plutons are aligned in a NE–SW direction and are extensively deformed by subhorizontal ductile thrust-related shearing and subsequent NNE–SSW trending folds. Here, we show that for the Dandong area the first deformation occurred between 195 and 193 Ma, based on K–Ar and
40
Ar/
39
Ar ages of muscovites from east–west-trending shear zones on the Liaodong Peninsula. Based on the field relationships between the plutons and structural fabrics, a range from 153 to 145 Ma is defined as the duration of the second deformation in the Dandong Granites. The third deformation is marked by the formation of NNE–SSW strike-slip faults between 135 and 95 Ma. This deduced age range is similar to an
40
Ar/
39
Ar age range of 128–132 Ma of initial sinistral strike-slip faulting of the Tan-Lu fault in Anhui Province and to a biotite cooling age of 100±2.3 Ma of the Yilan–Yitong segment of the Tan-Lu fault in the Jilin Province. These faults are transtensive and controlled the formation of pull-apart basins. However, during the third deformation, some metamorphic core complexes in Eastern China formed in the overlapping area between the large-scale sinistral faults. Our SHRIMP data also indicate that the Liaodong basement and its Early Mesozoic magmatism are similar to the Jiaodong basement and its Mesozoic magmatism. Therefore, the Early Mesozoic evolution of the Liaodong area, similar to that of the Jiaodong area, was also closely related to the Sulu orogen in the Early Mesozoic and to the Pacific subduction throughout the Mesozoic.
Deep crustal structures of the Yanshan intracontinental orogeny: a comparison with pericontinental and intercontinental orogenies
Authors: Shao J. , He G. , Zhang L.
Published: November 2007

The Mesozoic Yanshan intracontinental orogenic belt is developed in a weak zone on the northern margin of the North China Craton. We classify the Yanshan as an intracontinental orogen, as opposed to an intercontinental or pericontinental orogen, because of several geodynamic factors that differ from those of typical intercontinental orogens. These are: (1) reactivated tectonic activity on the lithospheric-scale faults since 1.8 Ga; (2) differential uplift of blocks during the Mesozoic, especially the great change of the elevation–subsidence framework at about 140 Ma, which induced building of the Yanshan Mountain and formation of the Cretaceous basins; (3) polycyclic evolutionary processes of active rift basins recorded by the Mesozoic volcanic and sedimentary strata; (4) Mesozoic tectonic regime reversion in the eastern North China Craton, demonstrated by petrological and geochemical evidence of crust–mantle interaction and supported by research on lithosphere thinning and ancient heat flow. Among these factors, the acute tectonic events of the lithosphere and evolution of active rift basins are directly affected by the upper mantle. The differential elevation of faulted blocks directly reflects the deep tectonic processes. Inherited features of the tectonic activities are characteristic of intracontinental orogenies and occur throughout all stages of the Yanshan movement but with different features. The deep controlling factors changed with time and combined with each other. The depth of tectonomagmatic activity became progressively shallower from 180 Ma to 130 Ma and then became deep again after 120 Ma. In the same period, extensional deformation was predominant in this area. The most important geodynamic characteristic of the Yanshan intracontinental orogeny is the tectonic regime inversion. Intracontinental orogeny is the response of the upper crust to the dramatic movements of the deep lithosphere. Its essential tectonic processes are thickening and subsequent thinning of the crust and lithosphere, which induces not only deformation of the rocks but also uplift of the mountain chain. Magmatic underplating is the most important factor of the Yanshan orogeny.
Metabolic acidosis decreases fetal myocardial isovolumic velocities in a chronic sheep model of increased placental vascular resistance
Authors: Acharya Ganesh , Räsänen Juha , Mäkikallio Kaarin , Erkinaro Tiina , Kavasmaa Tomi , Haapsamo Mervi , Mertens Luc , Huhta James C.
Published: November 2007

We hypothesized that acute fetal metabolic acidosis decreases fetal myocardial motion in a chronic sheep model of increased placental vascular resistance ( Rua). Eleven ewes and fetuses were instrumented at 118–122 days of gestation. After 5 days of recovery and 24 h of placental embolization to increase Rua, longitudinal myocardial velocities of the right and left ventricles and interventricular septum (IVS) were assessed at the level of the atrioventricular valve annuli via tissue Doppler imaging (TDI). Ventricular inflow (E and A waves) and outflow velocities were obtained, and cardiac outputs were calculated. All measurements were performed at baseline and during fetal acidosis caused by epidural anesthesia-induced maternal hypotension, which decreased uterine artery volume blood flow, fetal oxygenation, arterial pH, and base excess and increased lactate. Compared with baseline, the peak isovolumic myocardial contraction and relaxation velocities of the ventricles and IVS, early relaxation velocity (E′) of the ventricles, and systolic velocity of the IVS decreased during metabolic acidosis. The proportion of isovolumic contraction time of the cardiac cycle increased but the isovolumic relaxation and ejection time proportions and the TDI Tei index did not change. The E-to-E′ ratio for both ventricles was higher during metabolic acidosis than at baseline. During metabolic acidosis, right and left ventricular cardiac outputs remained unchanged compared with baseline. In sheep fetuses with increased Rua and acute metabolic acidosis, global cardiac function was preserved. However, acute metabolic acidosis impaired myocardial contractility during the isovolumic phase and relaxation during the isovolumic and early filling phases of the cardiac cycle.
Dietary salt enhances benzamil-sensitive component of myogenic constriction in mesenteric arteries
Authors: Jernigan Nikki L. , LaMarca Babette , Speed Josh , Galmiche Lauren , Granger Joey P. , Drummond Heather A.
Published: November 2007

Recent work from our laboratory indicates that epithelial Na+ channel (ENaC) function plays an important role in modulating myogenic vascular reactivity. Increases in dietary sodium are known to affect vascular reactivity. Although previous studies have demonstrated that dietary salt intake regulates ENaC expression and activity in epithelial tissue, the importance of dietary salt on ENaC expression in vascular smooth muscle cells (VSMCs) and its role in myogenic constriction is unknown. Therefore, the goal of the present study was to determine whether dietary salt modulates ENaC expression and function in myogenic vasoconstriction. To accomplish this goal, we examined ENaC expression in freshly dispersed VSMCs and pressure-induced vasoconstrictor responses in isolated mesenteric resistance arteries from normotensive Sprague-Dawley rats fed a normal-salt (NS; 0.4% NaCl) or high-salt (HS; 8% NaCl for 2 wk) diet. VSMCs from the mesenteric arteries of NS-fed animals express α-, β-, and γ-ENaC. The HS diet reduced whole cell α- and γ-ENaC and induced a pronounced translocation of β-ENaC from intracellular regions toward the VSMC membrane (∼336 nm). Associated with this change in expression was a change in the importance of ENaC in pressure-induced constriction. Pressure-induced constriction in NS-fed animals was insensitive to ENaC inhibition with 1 μM benzamil, suggesting that ENaC proteins do not contribute to myogenic constriction in mesenteric arteries under NS intake. In contrast, ENaC inhibition blocked pressure-induced constriction in HS-fed animals. These data suggest that dietary sodium regulates ENaC expression and the quantitative importance of the vascular ENaC signaling pathway contributing to myogenic constriction.
Low expression of the β-ENaC subunit impairs lung fluid clearance in the mouse
Authors: Randrianarison Nadia , Clerici Christine , Ferreira Chrystophe , Fontayne Alexandre , Pradervand Sylvain , Fowler-Jaeger Nicole , Hummler Edith , Rossier Bernard C. , Planès Carole
Published: November 2007

Transepithelial alveolar sodium (Na+) transport mediated by the amiloride-sensitive epithelial sodium channel (ENaC) constitutes the driving force for removal of fluid from the alveolar space. To define the role of the β-ENaC subunit in vivo in the mature lung, we studied a previously established mouse strain harboring a disruption of the β-ENaC gene locus resulting in low levels of β-ENaC mRNA expression. Real-time RT-PCR experiments confirmed that β-ENaC mRNA levels were decreased by >90% in alveolar epithelial cells from homozygous mutant (m/m) mice. β-ENaC protein was undetected in lung homogenates from m/m mice by Western blotting, but α- and γ-ENaC proteins were increased by 83% and 45%, respectively, compared with wild-type (WT) mice. At baseline, Na+-driven alveolar fluid clearance (AFC) was significantly reduced by 32% in m/m mice. Amiloride at the concentration 1 mM inhibited AFC by 75% and 34% in WT and m/m mice, respectively, whereas a higher concentration (5 mM) induced a 75% inhibition of AFC in both groups. The β2-agonist terbutaline significantly increased AFC in WT but not in m/m mice. These results show that despite the compensatory increase in α- and γ-ENaC protein expression observed in mutant mouse lung, low expression of β-ENaC results in a moderate impairment of baseline AFC and in decreased AFC sensitivity to amiloride, suggesting a possible change in the stoichiometry of ENaC channels. Finally, adequate β-ENaC expression appears to be required for AFC stimulation by β2-agonists.
Laboratory testing for heparin-induced thrombocytopenia is inconsistent in North America: A survey of North American specialized coagulation laboratories
Authors: Hayward Catherine , Moffat Karen , Moore Jane , Warkentin Theodore , Zehnder James , Price Elizabeth
Published: November 2007

Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy. As HIT is considered a clinico-pathologic entity, laboratory practices have an important role in diagnosing or excluding HIT. It was the objective of this study to assess the current status of laboratory testing for HIT in North America. An online survey consisting of 67 questions related to laboratory testing for HIT was developed by the North American Specialized Coagulation Laboratory Association (NASCOLA), and distributed to its 59 members. The survey included queries about HIT test ordering practices, HIT immunoassay and activation assays performed, and reporting practices. Data was collected from the 44 NASCOLA laboratories who responded. Of these sites, 88% performed immunoassays for HIT, commonly using commercial assays. However, sites varied in practices related to use of controls, immunoglobulin class of antibody detected, and in result interpretation and reporting. Platelet activation assays for HIT were performed by 36% of sites, commonly using assays of serotonin release (50%) or heparin- induced platelet aggregation (43%). Sites varied in the use of washed platelets versus platelet-rich plasma, controls, and heparin concentrations. This survey is the first comprehensive assessment of patterns of practice in HIT testing among diagnostic coagulation laboratories in North America. We observed sitespecific variability of testing methods encompassing all stages of testing, including pre-analytical handling, testing methodologies, and result interpretation and reporting. The variability in HIT platelet activation assay methods among institutions indicates a need for proficiency testing to assess assay performance,and for consensus guidelines on HIT laboratory testing.
Snake venom metalloproteinases, crotarhagin and alborhagin, induce ectodomain shedding of the platelet collagen receptor, glycoprotein VI
Authors: Wijeyewickrema Lakshmi , Gardiner Elizabeth , Moroi Masaaki , Berndt Michael , Andrews Robert
Published: November 2007

Glycoprotein (GP)VI, that binds collagen, together with GPIb- IX-V which binds von Willebrand factor, forms an adheso-signalling complex on platelets that initiates thrombus formation in haemostasis and thrombosis. In this study, we show that two snake venom metalloproteinases, crotarhagin and alborhagin, induce ectodomain shedding of GPVI by a mechanism that involves activation of endogenous platelet metalloproteinases. Alborhagin is a viper venom metalloproteinase from Trimeresurus albolabris, while crotarhagin is a previously undescribed toxin from the rattlesnake Crotalus horridus horridus (~60-kDa non-reduced and reduced). Like alborhagin, crotarhagin induces aggregation in human platelet-rich plasma (maximal activity, ~0.3 μg/ ml). Aggregation of washed platelets was inhibited by soluble GPVI ectodomain expressed as an Fc-fusion protein, confirming crotarhagin targeted GPVI. Treating washed platelets with crotarhagin or alborhagin resulted in time-dependent loss of surface GPVI and the appearance of an ~55-kDa soluble GPVI fragment in supernatants. Crotarhagin also induced shedding in GPVItransfected RBL-2H3 cells. Crotarhagin-induced shedding was metalloproteinase-dependent (inhibited by EDTA), but also blocked by inhibitors of GPVI signalling (Src kinase inhibitors, PP1 or PP2, or Syk inhibitor, piceatannol), indicating shedding required GPVI-dependent platelet activation. Together, the data suggest that the rattlesnake metalloproteinase, crotarhagin, and the viper toxin alborhagin, induce GPVI shedding by a mechanism involving activation of endogenous platelet metalloproteinases rather than direct cleavage of GPVI.
Time to Coronary Angiography and Outcomes Among Patients With High-Risk Non–ST-Segment–Elevation Acute Coronary Syndromes
Authors: Tricoci Pierluigi , Lokhnygina Yuliya , Berdan Lisa G. , Steinhubl Steven R. , Gulba Dietrich C. , White Harvey D. , Kleiman Neal S. , Aylward Philip E. , Langer Anatoly , Califf Robert M. , Ferguson James J. , Antman Elliott M. , Newby L. Kristin , Harrington Robert A. , Goodman Shaun G. , Mahaffey Kenneth W.
Published: November 2007

Background—

Optimal timing for an early invasive strategy in patients with non–ST-segment–elevation acute coronary syndrome remains unclear. We evaluated the relationship between time from hospital admission to coronary angiography and outcomes in high-risk patients with non–ST-segment–elevation acute coronary syndrome who underwent angiography within 48 hours of admission.

Methods and Results—

Data from 10 027 patients enrolled in the Superior Yield of the New Strategy of Enoxaparin, Revascularization, and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial were analyzed. Patients were grouped by 6-hour intervals of time from hospital admission to coronary angiography. Primary outcomes were 30-day death or myocardial infarction, in-hospital Thrombolysis In Myocardial Infarction (TIMI) and Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) major bleeding, and blood transfusion. Adjusted estimates of event rates were obtained by use of a multivariable methodology that included possible confounders through baseline and accounted for propensity of time to angiography. The landmark method was used to calculate odds ratios and 95% confidence intervals of outcomes for each time period adjusted for baseline and postbaseline clinical events. Overall, 9216 patients (92%) underwent angiography, 6352 (63%) within 48 hours. Unadjusted and adjusted rates of death/myocardial infarction increased with increasing time to angiography. The adjusted odds ratio for death/myocardial infarction in patients receiving angiography in <6 hours was 0.56 (95% confidence interval 0.41 to 0.74), whereas after 30 hours, there was no significant benefit compared with further delayed angiography. Major bleeding and transfusion did not vary significantly across time-to-angiography intervals.

Conclusions—

A decrease in the time to coronary angiography was associated with fewer ischemic outcomes and no increase in bleeding. Randomized clinical trials are needed to provide definitive evidence on optimal timing of coronary angiography but are difficult to design and conduct. Ongoing trials should instead clarify whether delaying angiography to administer aggressive upstream antithrombotic therapies is effective in the current setting of non–ST-segment–elevation acute coronary syndrome management.
Evaluation of Left Ventricular Filling Pressures by Doppler Echocardiography in Patients With Hypertrophic Cardiomyopathy
Authors: Geske Jeffrey B. , Sorajja Paul , Nishimura Rick A. , Ommen Steve R.
Published: November 2007

Background—

Diastolic dysfunction is a major pathophysiological abnormality in hypertrophic cardiomyopathy (HCM). Doppler echocardiographic parameters correlate with left ventricular (LV) filling pressures in other diseases, but it is unclear whether these findings apply to patients with HCM, who have multiple complex interrelated events leading to diastolic dysfunction. This study compares Doppler echocardiographic estimates of filling pressures to direct measurements of left atrial pressure (LAP) via catheterization in 100 patients with HCM.

Methods and Results—

One hundred patients who were symptomatic with HCM (New York Heart Association class III/IV, 82%) underwent measurement of early diastolic transmitral flow velocity (E) and mitral annular velocities (e′) with the use of transthoracic echocardiography within 48 hours of cardiac catheterization with direct measurement of LAP. In a subset of 42 patients, echocardiographic and catheterization measurements were performed simultaneously. Mean LAP directly correlated with medial E-e′ ratio in the overall population (
r
=0.44,
P
<0.0001) and also in the subgroup of patients who had simultaneous echocardiographic and catheterization studies (
r
=0.28,
P
=0.07). However, scatter was present. A calculated mean LV filling pressure was derived from the E-e′ ratio with the use of a previously described regression equation, and the 95% confidence limits of agreement with measured mean LAP exceeded ±18 mm Hg both for the overall group and for the subgroup who had simultaneous studies. Similar results were obtained with the lateral E-e′ ratio. Only 1 patient had a previously defined “normal” E-e′ ratio of <8.

Conclusions—

In symptomatic patients with HCM, Doppler echocardiographic estimates of LV filling pressure with the use of transmitral flows and mitral annular velocities correlate modestly with direct measurement of LAP. Given the complex nature of diastolic dysfunction in HCM, precise characterization of LV filling pressure in an individual patient cannot be determined with the use of these noninvasive parameters.
On Some Recent Advances in Multimodal Surgery Simulation: A Hybrid Approach to Surgical Cutting and the Use of Video Images for Enhanced Realism
Authors: Lim Yi-Je , Jin Wei , De Suvranu
Published: November 2007

In this paper, we present some recent advances in realistic surgery simulation including novel algorithms for simulating surgical cutting and techniques of improving visual realism of the simulated scenarios using images. Simulation of surgical cutting is one of the most challenging tasks in the development of a surgery simulator. Changes in topology during simulation render precomputed data unusable. Moreover, the process is nonlinear and the underlying physics is complex. Therefore, fully realistic simulation of surgical cutting at real-time rates on single processor machines is possibly out of reach at the present time. In this paper, we present a hybrid approach to the simulation of surgical cutting procedures by combining a node-snapping technique with a physically based meshfree computational scheme, the point-associated finite field (PAFF) approach, and empirical data obtained from controlled cutting experiments. To enhance the realism of the rendered scenarios, we propose an innovative way of using images obtained from videos acquired during actual surgical processes. Using a combination of techniques such as image mosaicing and view-dependent texture-mapping, we have been able to achieve excellent realistic effects with desired tissue glistening as the camera position is changed. Realistic examples are presented to showcase the results.
Pentecostal Witchcraft: Neoliberal Possession and Demonic Discourse in Ivoirian Pentecostal Churches
Authors: Newell Sasha
Published: November 2007

While Pentecostal churches derive their growing popularity in large part from their ability to combat witchcraft in society, I argue here that Pentecostalism is itself an alternative form of witchcraft discourse. As such, it falls prey to the same ambivalent relationship between power, success and social obligation that witchdoctors and politicians must face. I discuss Pentecostalism and witchcraft in terms of their relationship to neoliberal understandings of individual agency and economy in contrast to the moral economy of social obligations. At the same time I draw parallels between the ritual techniques of Pentecostalism and witchcraft cosmology, demonstrating that, despite Pentecostal churches' efforts to transcend the power of witchcraft, they in many cases become encompassed by witchcraft discourse, often taking on the appearance of witchcraft itself.
Anaphylactoid Reaction After the Use of Sodium Tetradecyl Sulfate: A Case Report
Authors: Brzoza Zenon , Kasperska-Zajac Alicja , Rogala Edmund , Rogala Barbara
Published: November 2007

Sodium tetradecyl sulfate is a sclerosing agent that has been widely used to treat varicose veins of the legs and digestive tract. Despite the multitude of side-effects of sclerotherapy procedures and sclerosing-drug administration, the medical literature reports only on a few cases of life-threatening hypersensitivity reactions resulting from sodium tetradecyl sulfate therapy. A case is reported of a 49-year-old woman who developed anaphylactoid reaction after the administration of the Fibro-vein for varicose veins in the legs. Attention is drawn to this adverse event and underlines the necessity for potential hypersensitivity assessment before the drug application.
Acute Effect of Cigarette Smoking on Heart Rate Variability
Authors: Karakaya Osman , Barutcu Irfan , Kaya Dayimi , Esen Ali Metin , Saglam Mustafa , Melek Mehmet , Onrat Ersel , Turkmen Muhsin , Esen Ozlem Batukan , Kaymaz Cihangir
Published: November 2007

Acute cigarette smoking enhances adrenergic activity and thus may be associated with hemodynamic changes in the cardiovascular system. In this study, the acute effect of cigarette smoking on heart rate variability (HRV) was studied. Fifteen subjects were included in the study. Time domain (the mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive R-R interval differences) and frequency domain (high-frequency, low-frequency ratio, and low-frequency/high-frequency ratio) parameters of HRV were obtained from all participants for each 5-minute segment: 5 minutes before and 5, 10, 15, 20, 25, and 30 minutes after smoking a cigarette. The mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive R-R interval differences significantly decreased within the first 5-minute period compared with baseline, and then the standard deviation of R-R interval increased within the 20- to 30-minute period. The low-frequency high-frequency ratio significantly decreased within the first 5 minutes after smoking and then remained unchanged throughout the study period. Similarly, low-frequency and high-frequency power increased within the first 5 minutes compared with baseline. Acute cigarette smoking alters HRV parameters, particularly within the first 5 to 10 minutes after smoking.
Vascular Remodeling After Carotid Artery Stenting
Authors: Puato M. , Piergentili C. , Zanardo M. , Rocchi R. , Giordan M. , Cardaioli P. , Pauletto P.
Published: November 2007

Carotid stenting is an alternative to endarterectomy for the treatment of carotid stenosis. To determine the role of vascular remodeling after stent placement, we studied 19 high surgical risk patients undergoing carotid stenting for severe stenosis. Using high-resolution ultrasound, we evaluated the intima-media thickness (IMT), the intima-intima diameter, and the adventitia-adventitia diameter at prespecified sites of the carotid artery tree during 3 years of follow-up. The IMT of internal carotid artery, at the site of maximum stenosis, increased significantly from 0 mm after 24 hours, to 0.41 mm at 3 months, to 0.48 mm at 6 months, and to 0.51 mm at 3 years of follow-up. In the same site, diameters and residual stenosis (range 29-24%) did not change over time. Our study showed that stent is self-expanding against the atherosclerotic plaque within the 3-year follow-up period. Despite neointima formation, the intima-intima diameter does not change without worsening of the residual stenosis.
Atherosclerosis Pathophysiology and the Role of Novel Risk Factors: A Clinicobiochemical Perspective
Authors: Mallika V. , Goswami Binita , Rajappa Medha
Published: November 2007

Atherosclerosis is the root cause of the biggest killer of the 21st century. Mechanisms contributing to atherogenesis are multiple and complex. A number of theories—including the role of dyslipidemia, hypercoagulability, oxidative stress, endothelial dysfunction, and inflammation and infection by certain pathogens—have been propounded from time to time explain this complex phenomenon. Recently it has been suggested that atherosclerosis is a multifactorial, multistep disease that involves chronic inflammation at every step, from initiation to progression, and that all the risk factors contribute to pathogenesis by aggravating the underlying inflammatory process. A better understanding of the pathogenesis of atherosclerosis will aid in devising pharmaceutical and lifestyle modifications for reducing mortality resulting from coronary artery disease (CAD).

A comprehensive literature search was conducted using the Web sites of the National Library of Medicine (http:// www.ncbl.nlm.nih.gov/) and PubMed Central, the US National Library of Medicine's digital archive of life sciences literature (http:// www.pubmedcentral.nih.gov/). The data were accessed from books and journals in which relevant articles in this field were published.

The whole spectrum of coronary artery disease evolves through various events that lead to the formation and progression of atherosclerotic plaque and finally its complications. Atherosclerosis is the culprit behind coronary artery disease, cerebral vascular disease, and peripheral vascular disease. The pathogenic mechanisms are varied and complex. Of late, the role of lipoprotein (a), homocysteine, and inflammation and infection as prime culprits in pathogenesis of CAD is the subject of intense research and debate. The appreciation of the role of inflammation in atherosclerosis provides a mechanistic framework to understand the clinical benefits of newer therapeutic strategies, and a better understanding of pathogenesis aids in formulating preventive and therapeutic strategies in reducing mortality resulting from CAD.

An in-depth knowledge of the various pathogenic mechanisms involved in atherosclerosis can help in substantiating the current existing knowledge about the CAD epidemic. This knowledge will help clinicians to better manage the disease, which affects Indians in its most severe form.
Angiographic and Clinical Outcomes of Rosiglitazone in Patients With Type 2 Diabetes Mellitus After Percutaneous Coronary Interventions: A Single Center Experience
Authors: Fang Ching-Chang , Yeun Tarl Fresner Ng Jao  , Yi-Chen  , Yu Ching-Lung , Chen Chi-Liang , Wang Shih-Pu
Published: November 2007

A beneficial effect of thiazolidinediones includes the reduction of intermediate markers, suggesting a potential for reducing atherosclerosis and restenosis. The objective of this study was to determine if rosiglitazone (RSG) reduced the odds of restenosis and if RSG improved the odds of clinical outcomes after percutaneous coronary intervention (PCI) in type 2 diabetes mellitus (DM) patients. A total of 609 patients with 734 lesions were selected from the period between January 1, 2001 and January 31, 2004. These patients were divided into 2 groups: a “control” group representing patients seen between January 1, 2001 and September 2002 when RSG was not available in our hospital and a “RSG treatment” group representing patients seen between September 2002 and January 31, 2004 when RSG was available in our hospital. Thus, 213 patients with 253 lesions (1.19 L/P) were placed in the RSG group and 396 patients with 481 lesions (1.21 L/P) were placed in the control group. Subgroup analysis based on the PCI received had 88 patients in the RSG arm receiving balloon angioplasty and 125 patients receiving coronary stenting; the control group had 187 and 209 patients, respectively, in the subgroups. Primary endpoint was angiographic restenosis at 6 months, and secondary endpoints were death, myocardial infarction, and target lesion revascularization. More patients in the control group were insulin-requiring, had poorer left ventricular function, but had a larger preprocedural minimal lumen diameter (pre-MLD). At 6 months, restenosis and reocclusion rates were lower in the RSG group (P = .014 and P = .006, respectively). Twenty-nine patients died in the control group versus 1 in the RSG group (P ≤ .001). RSG (P = .019), stenting (P = .005), preprocedural reference vessel diameter (P = .017), metformin (P = .022), pre-MLD (P < .001), hyperlipidemia (P = .016), and combined RSG and metformin (P = .020) were predictors of restenosis, while RSG (P = .016) and metformin (P = .029) were predictors of survival. In conclusion, RSG was found safe and well tolerated and was associated with reduced odds of restenosis, reocclusion, and mortality rates in type 2 DM patients independent of glycemic control and PCI performed.
Prevalence and Risk Factors of Peripheral Arterial Disease in a Selected Thai Population
Authors: Sritara Piyamitr , Sritara Chanika , Woodward Mark , Wangsuphachart Somjai , Barzi Federica , Hengprasith Bunlue , Yipintsoi Tada
Published: November 2007

Peripheral arterial disease (PAD) is a condition with high mortality, but it is amenable to secondary prevention. Data on its prevalence in Thailand are scarce. To study the prevalence of PAD in a middle-class, urban Thai population, a cross-sectional study was conducted at the Electric Generating Authority of Thailand's head plant, Nonthaburi, in 2002 and 2003 on all surviving and contactable employees and former employees who had participated in the first cardiovascular risk factors survey in 1985. Participants completed a structured questionnaire detailing their medical history, and they underwent a physical examination. A diagnosis of PAD was made when the ankle-brachial index (ABI) was < 0.9. Ankle-brachial index data were available for 98% of participants in the survey; 75% were men, and participants' ages ranged from 52 to 73 years. The overall prevalence of PAD was 5.2%. The age-standardized prevalence of PAD was 4% in men and 9% in women. Multiple logistic regression analysis found hypertension (OR = 1.7), female gender (OR = 1.9), current smoking (OR = 3.0), current alcohol drinking (OR = 0.41), and overweight (body mass index [BMI] > 25 kg/m 2, OR = 0.54) to be significant (P < .05) predictors of PAD. The prevalence of PAD in urban, middle-class Thais was similar to that in the population in developed countries.
Classification of Myocardial Contusion and Blunt Cardiac Trauma
Authors: RuDusky Basil M.
Published: November 2007

Myocardial injury caused by blunt chest trauma has been recognized with increased frequency over the past 2 decades. Increased awareness by physicians and the increased use of various clinical and laboratory diagnostic modalities have contributed to this recognition. Injuries range from inconsequential to catastrophic and can affect any or all areas of the heart: pericardium, myocardium, coronary arteries and veins, chordae, papillary muscles, valves, and great vessels. In addition to the medical importance of the diagnosis, substantial forensic implications have been known to arise. It is important to assess and classify properly the extent of the trauma and its prognostication as to the possibility of residual sequelae. A proposed classification is presented that has both medical and legal application. The uses of stages 0 (suspect), I (mild), II (moderate), III (severe), and IV (catastrophic) are illustrated in detail.
Cardiac Troponin T as a Prognostic Marker in Patients With Heart Failure : A 3-Year Outcome Study
Authors: Demir Mesut , Kanadaşı Mehmet , Akpınar Onur , Dönmez Yurdaer , Avkaroğulları Mahir , Alhan Cumhur , İnal Tamer , Şan Mustafa , Usal Ayhan , Demirtaş Mustafa
Published: November 2007

Cardiac troponin T (cTnT), a highly sensitive and specific indicator of myocardial cell death, may be elevated in congestive heart failure (CHF). The aims of this study were to test the hypothesis that decompensated CHF may be associated with an increase in cTnT release and to correlate between cTnT levels and patient outcomes. The authors studied 55 patients aged between 38 and 86 years (30 women and 25 men) who were hospitalized for CHF. Left ventricular ejection fraction (EF) was calculated by using modified Simpson's rule by echocardiography. cTnT levels were assessed. Troponin T ≥0.1 ng/mL was considered as positive. All patients were contacted by phone annually during the next 3 years, and their history of subsequent hospital admissions and current health status were recorded. cTnT was negative in 44 (80%) and positive in 11 (20%) patients. EF was significantly lower and NYHA was higher in cTnT-positive patients. During the 3-year follow-up period, 25 patients died from CHF. The mortality rate was 8/11 (72.7%) among cTnT-positive patients, whereas the mortality rate was 17/44 (38.6%) among cTnT-negative patients. There were significant relationships among positivity of cTnT, NYHA, EF, and mortality rate. Multivariate regression analysis yielded an independent relationship between positivity of cTnT, NYHA classification, and mortality rate. The percent of hospital admissions due to CHF was also higher in patients with cTnT positive (63.6% versus, 27.3%, p <0.05). In conclusion, this study shows that cTnT positivity is an independent risk factor in predicting the long-term mortality and morbidity rate in patients with CHF. Patients with worsening CHF may possibly be identified early on the basis of their elevated serum cTnT levels.
Myocardial Blush Grade: To Evaluate Myocardial Viability in Patients With Acute Myocardial Infarction
Authors: Seyfeli Ergun , Abaci Adnan , Kula Mustafa , Topsakal Ramazan , Eryol Namik K. , Arinc Huseyin , Ozdogru Ibrahim , Ergin Ali
Published: November 2007

Myocardial blush grade (MBG) is used to assess myocardial perfusion in the infarcted myocardium. The purpose of this study was to determine whether the analysis of myocardial blush grade after resolution of the acute phase of myocardial infarction is useful for assessing myocardial viability. The present study is consisted of 64 patients (55 men, mean age 55 ±11 years) who had acute myocardial infarction and nonoccluded stenosis (>50%) in an infarct-related artery. All the patients had thrombolysis in myocardial infarction (TIMI)-3 flow in the infarct-related artery on coronary angiograms. Myocardial viability was determined by single-photon emission computed tomography (SPECT) within the same week after coronary angiograms. MBG 0 in 5 (8%) patients, grade 1 in 10 (16%) patients, grade 2 in 23 (36%) patients, and grade 3 in 26 (40%) patients were present. Fifty-four (84%) of 64 patients showed myocardial viability by SPECT. Myocardial viability was demonstrated in 11 of 15 patients (74%) with MBG 0/1 and 43 of 49 patients (88%) with MBG 2/3. There was a weak relation between MBG and myocardial viability by correlation analysis (r = 0.28, p = 0.025). If MBG 0 and 1 are regarded as a sign of nonviable myocardium, and if MBG 2 and 3 are regarded as a sign of viable myocardium, the sensitivity of MBG for the prediction of myocardial viability was 79%, specificity was 40%, positive predictive value was 88%, and negative predictive value was 27%. MBG has a weak correlation with myocardial viability. Although sensitivity is fairly good, specificity is very low. We concluded that the diagnostic value of MBG is limited to detect myocardial viability in the infarcted region.
Population Pharmacokinetics and Pharmacodynamics of Peptidic Erythropoiesis Receptor Agonist (ERA) in Healthy Volunteers
Authors: Woo Sukyung , Krzyzanski Wojciech , Duliege Anne‐Marie , Stead Richar B. , Jusko Willia J.
Published: November 2007

Peptidic erythropoiesis receptor agonist is a synthetic, PEGylated peptide that can promote red blood cell production upon binding to the erythropoietin receptor. The objective of this study was to characterize the pharmacokinetics and erythropoietic effects of peptidic erythropoiesis receptor agonist in healthy volunteers. Plasma concentrations of peptidic erythropoiesis receptor agonist and pharmacodynamic responses were obtained after single intravenous injections at doses of 0.025, 0.05, and 0.1 mg/kg. Population pharmacokinetic/pharmacodynamic modeling was performed using NONMEM. Peptidic erythropoiesis receptor agonist exhibited nonlinear pharmacokinetics described by a 1‐compartment model with parallel elimination by Michaelis‐Menten and linear processes. A catenary, life span–based, indirect response model reflecting bone marrow erythroid and blood cells reflected the pharmacodynamics of peptidic erythropoiesis receptor agonist. A modest tolerance and rebound phenomenon in reticulocytes was modeled with negative feedback regulation related to hemoglobin. This pharmacokinetic/pharmacodynamic model well characterized the prolonged disposition, intrinsic pharmacologic parameters, and typical hematological system properties following single doses of peptidic erythropoiesis receptor agonist in normal subjects.
4-1BB regulates NKG2D costimulation in human cord blood CD8+ T cells
Authors: Kim Young-June , Han Myung-Kwan , Broxmeyer Hal E.
Published: November 2007

Ligation of NKG2D, a potent costimulatory receptor, can be either beneficial or detrimental to CD8+ cytotoxic T cell (CTL) responses. Factors for these diverse NKG2D effects remain elusive. In this study, we demonstrate that 4-1BB, another costimulatory receptor, is an essential regulator of NKG2D in CD8+ T cells. Costimulation of NKG2D caused down-modulation of NKG2D, but induced 4-1BB expression on the cell surface, even in the presence of TGF-β1, which inhibits 4-1BB expression. Resulting NKG2D−4-1BB+ cells were activated but still in an immature state with low cytotoxic activity. However, subsequent 4-1BB costimulation induced cytotoxic activity and restored down-modulated NKG2D. The cytotoxic activity and NKG2D expression induced by 4-1BB on NKG2D+4-1BB+ cells were refractory to TGF-β1 down-modulation. Such 4-1BB effects were enhanced by IL-12. In contrast, in the presence of IL-4, 4-1BB effects were abolished because IL-4 down-modulated NKG2D and 4-1BB expression in cooperation with TGF-β1, generating another CD8+ T-cell type lacking both NKG2D and 4-1BB. These NKG2D−4-1BB− cells were inert and unable to gain cytotoxic activity. Our results suggest that 4-1BB plays a critical role in protecting NKG2D from TGF-β1–mediated down-modulation. Co-expression of NKG2D and 4-1BB may represent an important biomarker for defining competency of tumor infiltrating CD8+ T cells.