bluuebunny/crossref_metadata_2025 huggingface dataset:
Emplacement mechanism of the Great Whin and Midland Valley dolerite sills
Authors: Goulty N.R.
Published: October 2005

The Great Whin and Midland Valley dolerite sill complexes appear to have been emplaced laterally from the walls of feeder dykes. The overall thickness of each sill increases with depth, as would be expected if the magma finally reached a state of hydrostatic equilibrium. Variations in the thickness of the sills with estimated intrusion depth imply that the head of magma was about 100 m below the contemporary ground surface in the areas of the present-day outcrops at the end of the intrusive episodes. Before hydrostatic equilibrium was established, the magma pressure would probably have been somewhat greater, so it is likely that intrusion of the sills was accompanied by the extrusion of flood basalts. Step-and-stair transgressions of the bedding are commonly found within the sills, mostly stepping downwards in the direction of bedding dip. The reason for this directionality is that the weight of sediments floating on an intruding sill has a downdip component that applies a tensile stress to intersecting fractures below the sill when magma is moving downdip, and to intersecting fractures above the sill when magma is moving updip.
Unlocking the spatial dimension: digital technologies and the future of geoscience fieldwork
Authors: McCaffrey K.J.W. , Jones R.R. , Holdsworth R.E. , Wilson R.W. , Clegg P. , Imber J. , Holliman N. , Trinks I.
Published: October 2005

The development of affordable digital technologies that allow the collection and analysis of georeferenced field data represents one of the most significant changes in field-based geoscientific study since the invention of the geological map. Digital methods make it easier to re-use pre-existing data (e.g. previous field data, geophysical survey, satellite images) during renewed phases of fieldwork. Increased spatial accuracy from satellite and laser positioning systems provides access to geostatistical and geospatial analyses that can inform hypothesis testing during fieldwork. High-resolution geomatic surveys, including laser scanning methods, allow 3D photorealistic outcrop images to be captured and interpreted using novel visualization and analysis methods. In addition, better data management on projects is possible using geospatially referenced databases that match agreed international data standards. Collectively, the new techniques allow 3D models of geological architectures to be constructed directly from field data in ways that are more robust compared with the abstract models constructed traditionally by geoscientists. This development will permit explicit information on uncertainty to be carried forward from field data to the final product. Current work is focused upon the development and implementation of a more streamlined digital workflow from the initial data acquisition stage to the final project output.
AN INTRODUCTION TO TRP CHANNELS
Authors: Ramsey I. Scott , Delling Markus , Clapham David E.
Published: October 2005

▪ Abstract  The aim of this review is to provide a basic framework for understanding the function of mammalian transient receptor potential (TRP) channels, particularly as they have been elucidated in heterologous expression systems. Mammalian TRP channel proteins form six-transmembrane (6-TM) cation-permeable channels that may be grouped into six subfamilies on the basis of amino acid sequence homology (TRPC, TRPV, TRPM, TRPA, TRPP, and TRPML). Selected functional properties of TRP channels from each subfamily are summarized in this review. Although a single defining characteristic of TRP channel function has not yet emerged, TRP channels may be generally described as calcium-permeable cation channels with polymodal activation properties. By integrating multiple concomitant stimuli and coupling their activity to downstream cellular signal amplification via calcium permeation and membrane depolarization, TRP channels appear well adapted to function in cellular sensation. Our review of recent literature implicating TRP channels in neuronal growth cone steering suggests that TRPs may function more widely in cellular guidance and chemotaxis. The TRP channel gene family and its nomenclature, the encoded proteins and alternatively spliced variants, and the rapidly expanding pharmacology of TRP channels are summarized in online supplemental material .
Vasoactive intestinal peptide upregulates MUC2 intestinal mucin via CREB/ATF1
Authors: Hokari Ryota , Lee Hwayoung , Crawley Suzanne C. , Yang Stacey C. , Gum James R. , Miura Soichiro , Kim Young S.
Published: October 2005

VIP exerts a spectrum of effects as a potent anti-inflammatory factor. In addition, VIP increases expression of MUC2, a major intestinal secretory mucin. We therefore investigated the effects of VIP on the promoter activity of the 5′-flanking region of the MUC2 gene. VIP activated MUC2 transcription in human colonic epithelial cells via cAMP signaling to ERK and p38. cAMP/Epac/Rap1/B-Raf signaling was not involved in MUC2 reporter activation. Furthermore, activation of MUC2 transcription was independent of many of the reported downstream effectors of G protein-coupled receptors, such as PKC, Ras, Raf, Src, calcium, and phosphoinositide 3-kinase. VIP induced cAMP response element-binding protein (CREB)/ATF1 phosphorylation, and this was prevented by treatment with inhibitors of either MEK or p38 and by PKA and MSK1 inhibitor H89. CREB/ATF1 and c-Jun were shown to bind to an oligonucleotide encompassing a distal, conserved CREB/AP1 site in the 5′-flanking region of the MUC2 gene, and this cis element was shown to mediate promoter reporter activation by VIP. This study has identified a new, functional cis element within the MUC2 promoter and also a new pathway regulating MUC2 expression, thus providing further insight into the molecular mechanism of VIP action in the colon. These findings are relevant to the normal biology of the colonic mucosa as well as to the development of VIP as a therapeutic agent for treatment of inflammatory bowel disease.
Epithelial Cells and Their Neighbors. IV. Bacterial contributions to intestinal epithelial barrier integrity
Authors: Ismail Anisa S. , Hooper Lora V.
Published: October 2005

Mammalian intestinal surfaces are in constant and intimate contact with a vast consortium of indigenous commensal bacteria. As a result, gut epithelia have evolved an array of strategies for limiting bacterial invasion into deeper tissues, helping to preserve the mutually beneficial nature of intestinal host-microbial relationships. In this review, we discuss a growing body of evidence indicating that commensal bacteria are actively involved in shaping the very barriers that confine them to the gut lumen. By modulating epithelial inflammatory responses, antimicrobial protein expression, and tissue repair functions, indigenous microbial populations are essential for the maintenance of healthy mucosal surfaces.
Abnormal intracellular lipid processing contributes to fat malabsorption in cystic fibrosis patients
Authors: Peretti Noël , Roy Claude C. , Drouin Eric , Seidman Ernest , Brochu Pierre , Casimir Georges , Levy Emile
Published: October 2005

A common feature of cystic fibrosis (CF) is the functional derangement of the exocrine pancreas, which affects output of pancreatic lipase. This condition results in severe dietary malabsorption due to the poor hydrolysis of triacylglycerol (TG) in the lumen of the small intestine. Despite the benefits of pancreatic enzyme supplements, patients with CF present with persistent intestinal fat malabsorption. The aim of the present investigation was to determine whether defects in the intracellular phase of lipid transport occur in this pathophysiology in addition to the known disturbed digestive processes. Our hypothesis was tested by incubating intestinal biopsies from six CF and six healthy subjects with radiolabeled lipid and protein precursors. Lipid esterification and secretion were markedly decreased by 22–31% and 38–42%, respectively, in CF samples, as noted by the low incorporation of [14C]palmitic acid into TGs, phospholipids, and cholesteryl esters in patients' duodenal explants and culture media compared with controls (100%). Accordingly, the output of TG-rich lipoproteins was substantially reduced ( P < 0.05), and a similar trend was observed for high-density lipoproteins. Because intestinal lipoprotein assembly/secretion shows an absolute requirement for apolipoprotein (apo) B-48, radioactive labeling experiments were performed; these experiments demonstrated a significantly ( P < 0.05) diminished synthesis of apoB-48 (40%) and apoA-I (30%). Given the critical role of microsomal triglyceride transfer protein in the formation of apoB-containing lipoproteins, its activity was determined and not found to be altered in CF intestinal tissue. Together, these results suggest that CF malabsorption may also be caused by defects in mucosal mechanisms leading to abnormal lipoprotein delivery into the blood circulation.
Isolation and characterization of IKr in cardiac myocytes by Cs+ permeation
Authors: Zhang Shetuan
Published: October 2005

Isolation of the rapidly activating delayed rectifier potassium current ( IKr) from other cardiac currents has been a difficult task for quantitative study of this current. The present study was designed to separate IKr using Cs+ in cardiac myocytes. Cs+ have been known to block a variety of K+ channels, including many of those involved in the cardiac action potential such as inward rectifier potassium current IK1 and the transient outward potassium current Ito. However, under isotonic Cs+ conditions (135 mM Cs+), a significant membrane current was recorded in isolated rabbit ventricular myocytes. This current displayed the voltage-dependent onset of and recovery from inactivation that are characteristic to IKr. Consistently, the current was selectively inhibited by the specific IKr blockers. The biophysical and pharmacological properties of the Cs+-carried human ether-a-go-go-related gene (hERG) current were very similar to those of the Cs+-carried IKr in ventricular myocytes. The primary sequence of the selectivity filter in hERG was in part responsible for the Cs+ permeability, which was lost when the sequence was changed from GFG to GYG, characteristic of other, Cs+-impermeable K+ channels. Thus the unique high Cs+ permeability in IKr channels provides an effective way to isolate IKr current. Although the biophysical and pharmacological properties of the Cs+-carried IKr are different from those of the K+-carried IKr, such an assay enables IKr current to be recorded at a level that is large enough and sufficiently robust to evaluate any IKr alterations in native tissues in response to physiological or pathological changes. It is particularly useful for exploring the role of reduction of IKr in arrhythmias associated with heart failure and long QT syndrome due to the reduced hERG channel membrane expression.
Development of insulin resistance and hyperphagia in Zucker fatty rats
Authors: Durham Holiday A. , Truett Gary E.
Published: October 2005

The onset of hyperphagia in the Zucker fatty ( fa/fa) rat occurs on a single day in postnatal development and could be driven by an increase in insulin sensitivity. To test this hypothesis, we performed insulin tolerance tests at several points in development. In rapidly growing juvenile rats, fatty rats are as insulin sensitive as lean rats at 4 wk of age but become increasingly insulin resistant as they became obese. During the suckling to weaning transition, fatty rats are insulin resistant at 2 wk of age, when they are exclusively suckling; they are also insulin resistant at 3 wk of age, when they are suckling and consuming solid food, but not hyperphagic. By 4 wk of age, when fatty rats are hyperphagic, they are as insulin sensitive as their lean littermates. These data indicate that fatty rats experience two phases of insulin resistance, punctuated by a brief period of insulin sensitivity that follows the onset of hyperphagia. To determine whether the increase in insulin sensitivity could be driving the onset of hyperphagia, insulin tolerance tests were performed from 21 to 27 days of age. Obese and lean rats became increasingly insulin resistant from 21 to 23 days of age and then became as insulin sensitive as lean rats by 25 days of age. These data show that increased insulin resistance precedes the onset of hyperphagia and increased insulin sensitivity follows the onset of hyperphagia. This pattern suggests that developmental perturbations in insulin signaling are likely to be involved in the onset of hyperphagia.
Quantitative 3D fluorescence technique for the analysis of en face preparations of arterial walls using quantum dot nanocrystals and two-photon excitation laser scanning microscopy
Authors: Ferrara Dardo E. , Weiss Daiana , Carnell Peter H. , Vito Ray P. , Vega David , Gao Xiaohu , Nie Shuming , Taylor W. Robert
Published: October 2005

Traditional imaging with one-photon confocal microscopy and organic fluorophores poses several challenges for the visualization of vascular tissue, including autofluorescence, fluorophore crosstalk, and photobleaching. We studied human coronary arteries (HCAs) and mouse aortas with a modified immunohistochemical (IHC) “en face” method using quantum dot (Qdot) bioconjugates and two-photon excitation laser scanning microscopy (TPELSM). We demonstrated the feasibility of multilabeling intimal structures by exciting multicolored Qdots with only one laser wavelength (750 nm). Detailed cell structures, such as the granular appearance of von Willebrand factor (VWF) and the subcellular distribution of endothelial nitric oxide synthase, were visualized using green dots (525 nm), even when the emission maximum of these Qdots overlapped that of tissue autofluorescence (510–520 nm). In addition, sensitive fluorescence quantification of vascular cell adhesion molecule 1 expression at areas of varying hemodynamics (intercostal branches vs. nonbranching areas) was performed in normal C57Bl/6 mice. Finally, we took advantage of the photostability of Qdots and the inherent three-dimensional (3D) resolution of TPELSM to obtain large z-stack series without photobleaching. This innovative en face method allowed simple multicolor profiling, highly sensitive fluorescence quantitation, and 3D visualization of the vascular endothelium with excellent spatial resolution. This is a promising technique to define the spatial and temporal interactions of endothelial inflammatory markers and quantify the effects of different interventions on the endothelium.
Endothelin receptors in teleost fishes: cardiovascular effects and branchial distribution
Authors: Stensløkken Kåre-Olav , Sundin Lena , Nilsson Göran E.
Published: October 2005

By observing gill blood flow using epi-illuminating microscopy, in parallel with cardiovascular recordings and immunohistochemistry, we have tried to identify the receptor mediating endothelin (ET) type 1 (ET1)-induced pillar cell contraction in the lamellae of the Atlantic cod ( Gadus morhua). Intra-arterial injection of the specific ETBreceptor agonist BQ-3020 induced dose-dependent increases in ventral aortic blood pressure, gill vascular resistance, and pillar cell area (indicating contraction). The specific ETAreceptor antagonist BQ-610 did not prevent either pillar cell contraction or increased gill vascular resistance induced by ET-1 injection. The cardiovascular responses were corroborated by the detection of ETBreceptor-like immunoreactivity (IR) associated with pillar cells in the lamellar region and in neuroendocrine cells. ETBreceptor-like IR was also found lining the muscle layer of lamellar arterioles and filament arteries. In contrast, strong ETAreceptor-like IR was found on branchial nerves throughout the filaments. In addition, ET-like IR was concentrated in neuroendocrine cells in the filament and lamellae. We also present data suggesting that ET-mediated pillar cell contraction is widespread among teleost fish, including Atlantic cod, rainbow trout ( Oncorhynchus mykiss), sculpin ( Myoxocephalus scorpius), and mackerel ( Scomber scombrus). Taken together, our results suggest that an ETB-like receptor mediates pillar cell contraction in fishes, whereas ETA-like receptors may serve another function in the gill, inasmuch as ETAreceptor-like IR is found on branchial nerves.
Sodium-level-sensitive sodium channel Nax is expressed in glial laminate processes in the sensory circumventricular organs
Authors: Watanabe Eiji , Hiyama Takeshi Y. , Shimizu Hidetada , Kodama Ryuji , Hayashi Noriko , Miyata Seiji , Yanagawa Yuchio , Obata Kunihiko , Noda Masaharu
Published: October 2005

Nax is an atypical sodium channel that is assumed to be a descendant of the voltage-gated sodium channel family. Our recent studies on the Nax-gene-targeting mouse revealed that Nax channel is localized to the circumventricular organs (CVOs), the central loci for the salt and water homeostasis in mammals, where the Nax channel serves as a sodium-level sensor of the body fluid. To understand the cellular mechanism by which the information sensed by Nax channels is transferred to the activity of the organs, we dissected the subcellular localization of Nax in the present study. Double-immunostaining and immunoelectron microscopic analyses revealed that Nax is exclusively localized to perineuronal lamellate processes extended from ependymal cells and astrocytes in the organs. In addition, glial cells isolated from the subfornical organ, one of the CVOs, were sensitive to an increase in the extracellular sodium level, as analyzed by an ion-imaging method. These results suggest that glial cells bearing the Nax channel are the first to sense a physiological increase in the level of sodium in the body fluid, and they regulate the neural activity of the CVOs by enveloping neurons. Close communication between inexcitable glial cells and excitable neural cells thus appears to be the basis of the central control of the salt homeostasis.
Neutral amino acid transport mediated by ortholog of imino acid transporter SIT1/SLC6A20 in opossum kidney cells
Authors: Ristic Zorica , Camargo Simone M. R. , Romeo Elisa , Bodoy Susana , Bertran Joan , Palacin Manuel , Makrides Victoria , Furrer Esther M. , Verrey François
Published: October 2005

Most neutral l-amino acid acids are transported actively across the luminal brush-border membrane of small intestine and kidney proximal tubule epithelial cells by a Na+ cotransport system named B0 that has been recently molecularly identified (B0AT1, SLC6A19). We show here that the opossum kidney-derived cell line OK also displays a Na+-dependent B0-type neutral l-amino acid transport, although with a slightly differing substrate selectivity. We tested the hypothesis that one of the two B0AT1-related transporters, SLC6A18 (ortholog of orphan transporter XT2) or SLC6A20 (ortholog of the recently identified mammalian imino acid transporter SIT1), mediates this transport. Anti-sense RNA to OK SIT1 ( oSIT1) but not to OK XT2 ( oXT2) inhibited Na+-dependent neutral amino acid transport induced by OK mRNA injected in Xenopus laevis oocytes. Furthermore, inhibition of oSIT1 gene expression in OK cells by transfection of siRNA and expression of shRNA selectively reduced the Na+-dependent uptake of neutral l-amino acids. Finally, expression of OK cell oSIT1 cRNA in X. laevis oocytes induced besides the transport of the l-imino acid l-Pro also that of neutral l-amino acids. Taken together, the data indicate that in OK cells SIT1 (SLC6A20) is not only an apical imino acid transporter but also plays a major role as Na+-dependent neutral l-amino acid transporter. A similar double role could be envisaged for SIT1 in mammalian kidney proximal tubule and small intestine.
Thermal effects of dorsal head immersion in cold water on nonshivering humans
Authors: Giesbrecht Gordon G. , Lockhart Tamara L. , Bristow Gerald K. , Steinman Allan M.
Published: October 2005

Personal floatation devices maintain either a semirecumbent flotation posture with the head and upper chest out of the water or a horizontal flotation posture with the dorsal head and whole body immersed. The contribution of dorsal head and upper chest immersion to core cooling in cold water was isolated when the confounding effect of shivering heat production was inhibited with meperidine (Demerol, 2.5 mg/kg). Six male volunteers were immersed four times for up to 60 min, or until esophageal temperature = 34°C. An insulated hoodless dry suit or two different personal floatation devices were used to create four conditions: 1) body insulated, head out; 2) body insulated, dorsal head immersed; 3) body exposed, head (and upper chest) out; and 4) body exposed, dorsal head (and upper chest) immersed. When the body was insulated, dorsal head immersion did not affect core cooling rate (1.1°C/h) compared with head-out conditions (0.7°C/h). When the body was exposed, however, the rate of core cooling increased by 40% from 3.6°C/h with the head out to 5.0°C/h with the dorsal head and upper chest immersed ( P < 0.01). Heat loss from the dorsal head and upper chest was approximately proportional to the extra surface area that was immersed (∼10%). The exaggerated core cooling during dorsal head immersion (40% increase) may result from the extra heat loss affecting a smaller thermal core due to intense thermal stimulation of the body and head and resultant peripheral vasoconstriction. Dorsal head and upper chest immersion in cold water increases the rate of core cooling and decreases potential survival time.
Portal vein cross-sectional area and flow and orthostatic tolerance: a 90-day bed rest study.
Authors: Arbeille Philippe P. , Besnard Stephane S. , Kerbeci Pascaline P. , Mohty Dania M.
Published: October 2005

The objective of this study was to evaluate the changes in the portal vein cross-sectional area (PV CSA) and flow during a stand test associated with orthostatic intolerance. Eighteen subjects underwent a 90-day head-down tilt (HDT) bed rest at 6°: 9 controls (Con) and 9 with flywheel exercise countermeasures (CM). At post-HDT, nine subjects (5 CM, 4 Con) were tolerant, and nine were intolerant. The PV CSA was measured by echography. We found that at HDT day 85, the PV CSA at rest had increased less in the CM subjects than in the Con (+12 vs. +27% from pre-HDT supine; P < 0.05), whereas it increased similarly in tolerant and intolerant subjects (23 and 16%, respectively). Two days after the HDT, there was a decrease in the PV CSA supine compared with the pre-HDT PV CSA supine that was similar for all groups (Con: −11%, CM: −21%; tolerant: −10%, intolerant: −16%; P < 0.05). The PV CSA decreased significantly less from supine to standing in the Con than in the CM group (−2 vs. −10% compared with the pre-HDT stand test; P < 0.05). The PV CSA also decreased significantly from supine to standing compared with the pre-HDT stand test in the tolerant group but not in the intolerant group (−20 vs. +2%; P < 0.05). From these findings, we conclude the following. 1) Because the portal vein is the only output from the splanchnic vascular area, we suggest that the lower reduction in the PV CSA and flow associated with orthostatic intolerance was related to a lower splanchnic arterial vasoconstriction. 2) The flywheel exercise CM helped to reduce the distention of the splanchnic network at rest and to maintain partially the splanchnic vasoconstriction, but it did not reduce the orthostatic intolerance.
Myocardial hypoperfusion/reperfusion tolerance with exercise training in hypertension
Authors: Reger Patricia O. , Barbe Mary F. , Amin Mamta , Renna Brian F. , Hewston Leigh Ann , MacDonnell Scott M. , Houser Steven R. , Libonati Joseph R.
Published: October 2005

The purpose of this study was to examine whether exercise training, superimposed on compensated-concentric hypertrophy, could increase myocardial hypoperfusion-reperfusion (H/R) tolerance. Female Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) (age: 4 mo; N = 40) were placed into a sedentary (SED) or exercise training (TRD) group (treadmill running; 25 m/min, 1 h/day, 5 days/wk for 16 wk). Four groups were studied: WKY-SED ( n = 10), WKY-TRD ( n = 10), SHR-SED ( n = 10), and SHR-TRD ( n = 10). Blood pressure and heart rate were determined, and in vitro isolated heart performance was measured with a retrogradely perfused, Langendorff isovolumic preparation. The H/R protocol consisted of a 75% reduction in coronary flow for 17 min followed by 30 min of reperfusion. Although the rate-pressure product was significantly elevated in SHR relative to WKY, training-induced bradycardia reduced the rate-pressure product in SHR-TRD ( P < 0.05) without an attenuation in systolic blood pressure. Heart-to-body weight ratio was greater in both groups of SHR vs. WKY-SED ( P < 0.001). Absolute and relative myocardial tolerance to H/R was greater in WKY-TRD and both groups of SHR relative to WKY-SED ( P < 0.05). Endurance training superimposed on hypertension-induced compensated hypertrophy conferred no further cardioprotection to H/R. Postreperfusion 72-kDa heat shock protein abundance was enhanced in WKY-TRD and both groups of SHR relative to WKY-SED ( P < 0.05) and was highly correlated with absolute left ventricular functional recovery during reperfusion ( R2= 0.86, P < 0.0001). These data suggest that both compensated hypertrophy associated with short-term hypertension and endurance training individually improved H/R and that increased postreperfusion 72-kDa heat shock protein abundance was, in part, associated with the cardioprotective phenotype observed in this study.
Dominant negative mutation of the TGF-β receptor blocks hypoxia-induced pulmonary vascular remodeling
Authors: Chen Yiu-Fai , Feng Ji-An , Li Peng , Xing Dongqi , Zhang Yun , Serra Rosa , Ambalavanan Namasivayam , Majid-Hassan Erum , Oparil Suzanne
Published: October 2005

The present study utilized a novel transgenic mouse model that expresses an inducible dominant negative mutation of the transforming growth factor (TGF)-β type II receptor (DnTGFβRII mouse) to test the hypothesis that TGF-β signaling plays an important role in the pathogenesis of chronic hypoxia-induced increases in pulmonary arterial pressure and vascular and alveolar remodeling. Nine- to 10-wk-old male DnTGFβRII and control nontransgenic (NTG) mice were exposed to normobaric hypoxia (10% O2) or air for 6 wk. Expression of DnTGFβRII was induced by drinking 25 mM ZnSO4water beginning 1 wk before hypoxic exposure. Hypoxia-induced increases in right ventricular pressure, right ventricular mass, pulmonary arterial remodeling, and muscularization were greatly attenuated in DnTGFβRII mice compared with NTG controls. Furthermore, the stimulatory effects of hypoxic exposure on pulmonary arterial and alveolar collagen content, appearance of α-smooth muscle actin-positive cells in alveolar parenchyma, and expression of extracellular matrix molecule (including collagen I and III, periostin, and osteopontin) mRNA in whole lung were abrogated in DnTGFβRII mice compared with NTG controls. Hypoxic exposure had no effect on systemic arterial pressure or heart rate in either strain. These data support the hypothesis that endogenous TGF-β plays an important role in pulmonary vascular adaptation to chronic hypoxia and that disruption of TGF-β signaling attenuates hypoxia-induced pulmonary hypertension, right ventricular hypertrophy, pulmonary arterial hypertrophy and muscularization, alveolar remodeling, and expression of extracellular matrix mRNA in whole lung.
Disorders of glucose metabolism in sleep apnea
Authors: Punjabi Naresh M. , Polotsky Vsevolod Y.
Published: October 2005

Sleep is a complex behavioral state that occupies one-third of the human life span. Although viewed as a passive condition, sleep is a highly active and dynamic process. The sleep-related decrease in muscle tone is associated with an increase in resistance to airflow through the upper airway. Partial or complete collapse of the airway during sleep can lead to the occurrence of apneas and hypopneas during sleep that define the syndrome of sleep apnea. Sleep apnea has become pervasive in Western society, affecting ∼5% of adults in industrialized countries. Given the pandemic of obesity, the prevalence of Type 2 diabetes mellitus and metabolic syndrome has also increased dramatically over the last decade. Although the role of sleep apnea in cardiovascular disease is uncertain, there is a growing body of literature that implicates sleep apnea in the pathogenesis of altered glucose metabolism. Intermittent hypoxemia and sleep fragmentation in sleep apnea can trigger a cascade of pathophysiological events, including autonomic activation, alterations in neuroendocrine function, and release of potent proinflammatory mediators such as tumor necrosis factor-α and interleukin-6. Epidemiologic and experimental evidence linking sleep apnea and disorders of glucose metabolism is reviewed and discussed here. Although the cause-and-effect relationship remains to be determined, the available data suggest that sleep apnea is independently associated with altered glucose metabolism and may predispose to the eventual development of Type 2 diabetes mellitus.
Increased intramyocellular lipid accumulation in HIV-infected women with fat redistribution
Authors: Torriani Martin , Thomas Bijoy J. , Barlow Robert B. , Librizzi Jamie , Dolan Sara , Grinspoon Steven
Published: October 2005

The human immunodeficiency virus (HIV)-lipodystrophy syndrome is associated with fat redistribution and metabolic abnormalities, including insulin resistance. Increased intramyocellular lipid (IMCL) concentrations are thought to contribute to insulin resistance, being linked to metabolic and body composition variables. We examined 46 women: HIV infected with fat redistribution ( n = 25), and age- and body mass index-matched HIV-negative controls ( n = 21). IMCL was measured by1H-magnetic resonance spectroscopy, and body composition was assessed with computed tomography, dual-energy X-ray absorptiometry (DEXA), and magnetic resonance imaging. Plasma lipid profile and markers of glucose homeostasis were obtained. IMCL was significantly increased in tibialis anterior [135.0 ± 11.5 vs. 85.1 ± 13.2 institutional units (IU); P = 0.007] and soleus [643.7 ± 61.0 vs. 443.6 ± 47.2 IU, P = 0.017] of HIV-infected subjects compared with controls. Among HIV-infected subjects, calf subcutaneous fat area (17.8 ± 2.3 vs. 35.0 ± 2.5 cm2, P < 0.0001) and extremity fat by DEXA (11.8 ± 1.1 vs. 15.6 ± 1.2 kg, P = 0.024) were reduced, whereas visceral abdominal fat (125.2 ± 11.3 vs. 74.4 ± 12.3 cm2, P = 0.004), triglycerides (131.1 ± 11.0 vs. 66.3 ± 12.3 mg/dl, P = 0.0003), and fasting insulin (10.8 ± 0.9 vs. 7.0 ± 0.9 μIU/ml, P = 0.004) were increased compared with control subjects. Triglycerides ( r = 0.39, P = 0.05) and extremity fat as percentage of whole body fat by DEXA ( r = −0.51, P = 0.01) correlated significantly with IMCL in the HIV but not the control group. Extremity fat (β = −633.53, P = 0.03) remained significantly associated with IMCL among HIV-infected patients, controlling for visceral abdominal fat, abdominal subcutaneous fat, and antiretroviral medications in a regression model. These data demonstrate increased IMCL in HIV-infected women with a mixed lipodystrophy pattern, being most significantly associated with reduced extremity fat. Further studies are necessary to determine the relationship between extremity fat loss and increased IMCL in HIV-infected women.
Leg crossing, muscle tensing, squatting, and the crash position are effective against vasovagal reactions solely through increases in cardiac output
Authors: Krediet C. T. Paul , de Bruin Ivar G. J. M. , Ganzeboom Karin S. , Linzer Mark , van Lieshout Johannes J. , Wieling Wouter
Published: October 2005

Tensing of lower body muscles without or with leg crossing (LBMT, LCMT), whole body tensing (WBT), squatting, and sitting with the head bent between the knees (“crash position,” HBK) are believed to abort vasovagal reactions. The underlying mechanisms are unknown. To study these interventions in patients with a clinical history of vasovagal syncope and a vasovagal reaction during routine tilt table testing, we measured blood pressure (BP) continuously with Finapres and derived heart rate, stroke volume, cardiac output (CO), and total peripheral resistance using Modelflow. In series A ( n = 12) we compared LBMT to LCMT. In series B ( n = 9), WBT was compared with LCMT. In series C ( n = 14) and D ( n = 9), we tested squatting and HBK. All maneuvers caused an increase in BP, varying from a systolic rise from 77 ± 8 to 104 ± 18 mmHg ( P < 0.05) in series A during LBMT to a rise from 70 ± 10 to 123 ± 9 mmHg ( P < 0.05) in series B during LCMT. In each maneuver, the BP increase started within 3–5 s from start of the maneuver. In all maneuvers, there was an increase in CO varying from 54 ± 12% of baseline to 94 ± 21% in WBT to a rise from 65 ± 17% to 110 ± 22% in LCMT in series A. No maneuver caused significant change in total peripheral resistance. We conclude that the mechanism underlying the effects of these maneuvers is exclusively an increase in CO.
Comparison of Polymorphonuclear Leukocyte Functions in Elderly Patients and Healthy Young Volunteers
Authors: Göçer Pervin , Gürer Ümran S. , Erten Nilgün , Palandüz Şükrü , Rayaman Erkan , Akarsu Burçak , Karan Akif , Çevikbaş Adile
Published: October 2005

Objective: To compare the polymorphonuclear leukocyte (PMN) functions (phagocytosis and intracellular killing activity) of elderly patients with healthy young volunteers. Subjects and Methods: Fifty-nine elderly patients who had various diseases (cancer, hypertension and diabetes mellitus, DM) and 10 healthy young volunteers were included in this study. Ficoll-Hypaque gradient centrifugation was used to isolate PMNs from venous blood containing EDTA (0.1 g/ml). Phagocytosis and intracellular killing activity of neutrophils were assayed using a modification of Alexander’s method, in which serum opsonins, number of neutrophils and number of microorganisms are standardized in order to detect both increases and decreases in phagocytosis and intracellular killing as well as combined abnormalities of these two functions. The least significant difference test was used to compare the results in the two groups. Results: Phagocytic activity of PMNs from patients with cancer was significantly higher than that of healthy young volunteers (p < 0.05) and elderly patients with hypertension and DM (p < 0.05). There was no statistical difference between the phagocytic activity of PMNs from elderly patients with hypertension and DM and healthy young volunteers (p > 0.05). The intracellular killing activity of PMNs from elderly patients with hypertension, DM and cancer was significantly lower than that of healthy young volunteers (p = 0.001, p < 0.0001, p = 0.003, respectively). Conclusions: The intracellular killing activity of PMNs from elderly patients was significantly decreased when compared with that of healthy young volunteers. Ageing, chronic diseases and drugs used in the treatment of these elderly patients may be the cause for decreased intracellular killing activity.
Renal Artery Stenosis in Patients with Peripheral Vascular Disease in Kuwait
Authors: Ahmed A. , Nampoory M.R.N. , Sheikh M. , Johny K.V.
Published: October 2005

Objective: The aim of this study was to identify the incidence of atherosclerotic renal artery stenosis (RAS) in patients with peripheral vascular disease (PVD) and its relation to any known risk factors. Subjects and Methods: This prospective study was conducted on 212 patients who were subjected to peripheral angiography for symptoms of PVD over a 3-year period from 1995 to 1998 at the Mubarak Al-Kabeer Hospital, Kuwait. Angiographic evidence of atherosclerotic disease and its severity was recorded in renal, abdominal aorta, iliac, femoral, popliteal and below-knee arteries. In addition, a detailed search of identifiable risk factors was done using history, clinical examination and laboratory studies. Results: The incidence of significant atherosclerotic RAS (more than 50% diameter stenosis) in patients with PVD was 15/212 (7.07%) with no significant difference in ratio between males and females (p = 0.3) compared to that of PVD alone. Patients with common iliac and femoral artery lesions had a high incidence of RAS (93.3 and 86.7%, respectively) with more than 80% probability in RAS patients with involvement of these vessels. There was significant renal impairment (p < 0.005), as assessed by serum creatinine levels, in patients with RAS compared to those who did not have it. There was a high incidence of smoking in patients with RAS (p = 0.02), and smoking was the only risk factor identified in these subjects. Conclusions: Patients with iliac or femoral atherosclerotic disease have a high probability of associated RAS. Presence of renal impairment in patients with PVD is highly indicative of RAS. Smoking is the only identified risk factor for RAS in association with PVD in our population.
Primary Thyroid Malignancies in Tehran, Iran
Authors: Larijani Bagher , Mohagheghi Mohammad Ali , Bastanhagh Mohammad Hassan , Mosavi-Jarrahi Ali Reza , Haghpanah Vahid , Tavangar Seyed Mohammad , Bandarian Fatemeh , Khaleghian Nasim
Published: October 2005

Objective: The aim of this study was to present a descriptive epidemiology of primary thyroid cancer in Tehran, Iran, using cancer registry data. Subjects and Methods: All cases of thyroid cancer registered from 1998 to 2001 in Tehran Metropolitan Area Population-Based Cancer Registry were used for this study. The incidence of thyroid cancer was estimated for the area covered by the cancer registry. Survival of patients was ascertained by telephone call to the patients or the patient’s family and/or linkage of registry data to mortality data from the Bureau of Vital Statistics. Patient’s survival was based on sex, age and morphological type of tumour. Results: Four hundred and twenty-nine cases of primary thyroid cancer were registered in the Tehran Metropolitan Area Cancer Registry. The incidence of thyroid cancer was 3.5 and 1.0 per 100,000 population per year for females and males, respectively. Seventy percent of tumours were papillary, 11% follicular, 6.2% medullary, and the rest were other subtypes. The papillary and follicular variants occurred in younger age: 43 ± 16 and 46 ± 13 years, respectively; the medullary and anaplastic variants occurred in older age: over 50 years. A 5-year survival rate was 82.2%, with median survival of 66 months and 95% confidence interval of 63 and 69 months. Men and women had a similar survival experience.Conclusions: While the incidence of thyroid cancer was slightly high, the descriptive epidemiology of thyroid cancer in Tehran did not manifest a unique feature. Tehran patients experienced a high rate of survival, and the survival time for males and females was similar.
A Clinic Investigation into Prehospital and Emergency Department Delays in Acute Stroke Care
Authors: Keskin Özcan , Kalemoğlu Murat , Ulusoy Rifat Eralp
Published: October 2005

Objective: The aim of our study was to investigate the factors which cause prehospital and emergency department (ED) delays in acute stroke care. Subjects and Methods: We prospectively studied 229 acute stroke patients (median age: 71 ± 19 years, 90 female and 139 male) who presented to the ED of the Gulhane Military Teaching Hospital, Istanbul, Turkey. Prehospital delay was defined as time from symptom onset to arrival at the ED. Emergency delay was defined as time from initial examination in the ED to arrival at the Neurology Intensive Care Unit. Results: The median interval of prehospital and emergency delays were 92.66 and 53 min, respectively. The major cause of the prehospital delay was the time from symptom onset to first call for medical help (68.21 min, 73.93%, β coefficients: 0.99; p < 0.001), and the major cause of the ED delay was waiting for the neurological consultation (21.28 min, 39.6%), β coefficients: 0.03; p < 0.001). Conclusion: The results indicate that prehospital and ED delays are due to late decision to seek medical care and delayed neurological consultation. Hence, educational campaigns are needed to increase public awareness of stroke signs and the necessity of calling emergency services immediately when persons are suffering a possible stroke. Equally, ED physicians need to be trained in the recognition of symptoms and signs of acute stroke and the necessity for rapid neurological evaluation.
Pulmonary Arteriovenous Malformation Presenting with Severe Hypoxemia
Authors: Ayed Adel K. , Bazerbashi Samer , Uthaman Babu
Published: October 2005

Objective: To report a case of right pulmonary arteriovenous malformation (PAVM) affecting the right upper lobe, following the incidence of empyema thoracis in the contralateral lung. Clinical Presentation and Intervention: A 19-year-old, previously healthy male presented with acute respiratory distress, left pleuritic chest pain, fever and hypoxemia. Clinical findings, laboratory and radiological examinations including pulmonary angiogram were consistent with the diagnosis of left pneumonia complicated with parapneumonic pleural effusion and right upper lobe PAVM. The patient was intubated and ventilated because of persistent hypoxemia. He was successfully treated by percutaneous transcatheter embolization. Conclusion: This case shows that percutaneous transcatheter embolization is a safe and effective first option for the treatment of PAVM.
Abdominal Wall Endometriosis: A Diagnostic Dilemma for Surgeons
Authors: Kocakusak Ahmet , Arpinar Esra , Arikan Soykan , Demirbag Nilgun , Tarlaci Ahmet , Kabaca Canan
Published: October 2005

Objective: To report 3 cases of endometriosis of the abdominal wall, a disease which is unfamiliar to general surgeons because of the potential pitfalls in its diagnosis. Clinical Presentation and Intervention: Three patients were referred to our general surgery clinic for abdominal masses. Incisional hernia and an abdominal mass were initially suspected in 2 patients, while a preoperative diagnosis of a rectus abdominis hematoma was made in the third because she had no history of previous surgery. Pain was a remarkable complaint in only one of the present cases.Abdominal wall endometriosis was diagnosed only upon histological examination postoperatively. In all cases, ultrasonography revealed hypoechogenic masses, and computed tomography showed that these masses had spiculations, and macroscopic views of the resected masses revealed well-demarcated margins without peritoneal involvement. All patients were treated with wide radical resections followed by polytetrafluoroethylene patch grafting. They were discharged from hospital on either the 2nd or the 3rd postoperative day uneventfully, and during follow-up there were no signs of pelvic endometriosis, as confirmed by ultrasonography, CA 125 measurement, gynecological consultation and examination. Conclusion: Since the diagnosis of scar endometrioma is rarely established prior to surgery, endometriosis should be included in the differential diagnosis of masses on the abdominal wall.
Nonalcoholic Wernicke’s Encephalopathy with Prominent Astasia and Optic Neuropathy
Authors: Gokce M. , Bulbuloglu E. , Tuncel D. , Ozdemir G. , Kale I.T.
Published: October 2005

Objective: To present a case with nonalcoholic Wernicke’s encephalopathy (WE) developing astasia and optic neuropathy as major sequelae. Clinical Presentation and Intervention: A 47-year-old woman developed WE following operation for pyloric stenosis. She received total parenteral nutrition before and after operation, but on the second postoperative day she developed visual hallucination and confusion, followed by nystagmus, ophthalmoplegia, apathy, dysarthria and coma. Although the patient has recovered with thiamine treatment, astasia and optic neuropathy persistedas major morbidities. Conclusion: The report shows that astasia and optic neuropathy may be prominent sequelae in some patients with WE.
Is the Western Scrub-Jay (Aphelocoma californica) Really an Underdog among Food-Caching Corvids when It Comes to Hippocampal Volume and Food Caching Propensity?
Authors: Pravosudov Vladimir V. , de Kort Selvino R.
Published: October 2005

Food caching has been linked to better performance on spatial memory tasks and enlarged hippocampal volume in both birds and mammals. Within food-caching birds, it has also been predicted that species less reliant on stored food should have inferior spatial memory and a smaller hippocampus compared to species that depend heavily on food caches. Several comparisons suggest that North American corvids have a significantly smaller hippocampus and overall brain volume compared to the Eurasian corvid species and that western scrub-jays (Aphelocoma californica) have a smaller hippocampus compared to the more specialized Clark’s nutcracker. Here we present the largest data set of scrub-jay brains and, in contrast to previous reports, show that relative to body mass western scrub-jays have a brain size similar to the largest brain size of Eurasian corvids. The relative hippocampal volume of scrub-jays is also among the largest of all investigated corvids. These findings may not be surprising considering that scrub-jays have been reported to have remarkable cognitive capacities such as episodic-like memory and experience projection. Our data suggest that many previously made assumptions about western scrub-jays as less specialized food hoarders might be an oversimplification and that simple categorization of species into specialized and non-specialized hoarders might not provide useful insights into the evolution of memory and the hippocampus.
Genetic Polymorphism and Th1/Th2 Orientation
Authors: Bottini N. , Gloria-Bottini F. , Amante A. , Saccucci P. , Bottini E.
Published: October 2005

Background: It is likely that besides developmental and environmental factors, genetic factors also play an important role in Th1/Th2 orientation and susceptibility to related disorders. Thus, for each genetic factor involved one would expect an opposite pattern of susceptibility towards Th1- and Th2-associated diseases. Methods: We report a comparative analysis of the pattern of association of four genetic polymorphisms with bronchial asthma (Th2 disease) and Crohn’s disease (CD; Th1 disease). The study population included 291 Roman children with bronchial asthma and 72 adult Romans with CD, and haptoglobin, adenosine deaminase (ADA), acid phosphatase locus 1 (ACP1) and MN phenotypes were determined. Results: Compared with controls from the same population, the pattern of phenotype association observed in bronchial asthma is exactly opposite to that observed in CD. The analysis of pairwise gametic type distribution for ACP1, ADA and MN polymorphisms has shown that the pattern of differences between bronchial asthma and controls is opposite to that observed between CD and controls. Conclusions: The pattern of differences between bronchial asthma versus CD is compatible with the hypothesis that some of the genetic systems considered contribute to Th1/Th2 orientation.