bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison Between Intermittent and Continuous Measurement of Cardiac Output After Acute Normovolemic Hemodilution in Pigs
Authors: Otsuki Denise A. , Cardieri Fernando A. , Schmidt André P. , Brudniewski Marcio , Fantoni Denise T. , Auler José O.C.
Published: May 2006

Abstract:  Continuous cardiac output (CO) and mixed venous oxygen saturation (SvO2) determined through the pulmonary artery catheter may be helpful in monitoring hemodynamic conditions in critically ill patients. This study aimed to evaluate CO and SvO2 in a model of acute normovolemic hemodilution (ANH), analyzing the accuracy of the continuous versus intermittent method for CO and SvO2 measurement in pigs. Twenty‐three pigs were enrolled to three groups: control, ANH with 6% hydroxyethyl starch (HES), or ANH with lactated Ringer’s (LR) solution. After hemodilution, we showed that SvO2 was reduced in both groups, mainly in LR animals (P < 0.05). Regarding the evaluation of CO, we showed an increase in both groups submitted to ANH (P < 0.05). Through Bland–Altman analysis, we showed that the continuous CO catheter presented lower values than the intermittent method after hemodilution, mainly with HES (P < 0.001), and there was no difference in the measurement of SvO2. The ANH promoted a decrease in SvO2 and an increase in CO values, mainly in animals submitted to hemodilution with HES. The use of continuous and intermittent (laboratory) measurement of SvO2 showed clinical applicability and good agreement, an effect not reproduced by the CO measurement. New studies are needed to further investigate the agreement between the continuous and intermittent methods for the measurement of CO in adverse hemodynamic conditions such as ANH.
Numerical Analysis of the Inner Flow Field of a Biocentrifugal Blood Pump
Authors: Chua Leok Poh , Song Guoliang , Lim Tau Meng , Zhou Tongming
Published: May 2006

Abstract:  Implantable ventricular assist devices have been regarded as a promising instrument in the clinical treatment of patients with severe heart failures. In this article, a three‐dimensional model of the Kyoto‐NTN magnetically suspended centrifugal blood pump was generated and a computational fluid dynamics solution of the inner flow field of the pump including the static pressure distributions, velocity profiles, and the shear stress distributions of the blood was presented. The results revealed that reverse flow generally occurred in the impeller blade channels during the operation of the pump, due to the imbalance of the flow and the pressure gradient generated in the blade channels. The flow pattern at the exit of the blade channels was varying with its angular positions in the pump. The reverse flow at the exit of the impeller blade channels was found to be closely related with the static pressure distribution in the volute passage. Higher pressure in the volute caused severe backflow from the volute into the blade channels. To clarify the effects of a moving impeller on the blood, shear stresses of the blood in the pump were investigated according to the simulation results. The studies indicated that at the beginning of the splitter plate and the cutwater, the highest shear stress exceeded 700 Pa. At other regions such as the inlet and outlet of the impeller blade channels and some regions in the volute passage, shear stresses were found to be about 200 Pa. These areas are believed to have a high possibility of rendering blood trauma.
Long‐Term Survivors After Valve Replacement With a Starr‐Edwards Mitral Disk Valve Prosthesis
Authors: Aoyagi Shigeaki , Fukunaga Shuji , Tayama Eiki , Arinaga Koichi , Oda Takeshi , Kosuga Tomokazu
Published: May 2006

Abstract:  We report four long‐term survivors after valve replacement with a Starr‐Edwards (S‐E) mitral caged‐disk valve. A model 6520 disk valve, size 3M, had been used in all of the four patients. Of the four patients, three underwent replacement of the disk valves 23, 24, and 26 years after mitral valve replacement (MVR), respectively. A pacemaker was implanted in the remaining patient 33 years after MVR. The S‐E disk valves were considered hemodynamically slightly stenotic compared with modern bileaflet valves. No disk wear was detected in any of the three explanted valves, and in the remaining patient, a noninvasive evaluation of the disk showed that it was functioning normally. These results suggest the favorable long‐term durability of the S‐E disk valve.
Thick Nb‐Doped Bismuth Titanate Film with Controllable Grain Orientation
Authors: Chen Weiwu , Kinemuchi Yoshiaki , Watari Koji , Tamura Takuya , Miwa Kenji
Published: May 2006

In the current work, we reported a potential approach to obtain thick ceramic films with controllable grain orientation based on magnetic alignment and polymerization techniques. The slurry containing 40 vol% Bi4Ti2.96Nb0.04O12 (BINT) ceramic powder, monomer, initiator, and catalyst was drop coated on a Pt substrate and then moved into a vertical 10 T magnetic field. In 1–2 min, the ceramic particles were aligned by a strong magnetic force in slurry and then in situ locked by polymerization on the substrate. After sintering at 1000°C, a BINT ceramic film (50–80 μm in thickness) with a highly a/b plane orientation was obtained. Theoretically, the grain orientation in the films can be easily controlled by adjusting the magnetic field direction. This approach is readily applicable to other materials with a non‐cubic structure and is expected to facilitate the fast preparation of grain‐oriented thick films.
Nanoscratch Studies of Uncoated and Coated Ceramic Matrix Composite Materials
Authors: Bhushan Bharat , Wei Guohua
Published: May 2006

Ceramics and cermets (ceramic matrix composites) are commonly used for various structural and tribological applications. Pullout of phases at high loads in a composite can be an issue and can be alleviated using a hard overcoat. In this study, nanoscratch and nanoindentation experiments on a SiC composite impregnated with graphite were carried out using a depth‐sensing nanoindenter. Additional indentation studies on the graphite phase were carried out to examine whether it becomes fractured or dislodges readily. Additionally, experiments were carried out to study scratch performance and nanohardness of a hard overcoat and its ability to protect SiC composite phases underneath. We find that a hard overcoat adequately protects the substrate underneath. Finally, nanoscratch and nanoindentation experiments were performed on pure SiC as well as commonly used manufactured carbon–carbon graphite. It is found that SiC exhibits the highest scratch resistance and carbon graphite the least.
Melting of a Semitransparent Bed of Particles by Convection and Radiation
Authors: Tseng Charles C. , Viskanta Raymond
Published: May 2006

A theoretical model has been developed to study heating and melting of porous media comprised of semitransparent particles. The heating and melting phases are treated by two different models. Heat transfer by conduction and radiation in the bed of particles is approximated using the effective thermal conductivity concept. The melt is assumed to accumulate at the top of the unmelted bed and not to run off after the melting has started. Radiative transfer in the one‐dimensional melt layer is treated rigorously, and the spectral nature of radiation is accounted for. The convective and radiative heating of the bed and the melt layer are treated parametrically. The results of calculations for different bed thicknesses are reported, and sensitivity studies involving the heat transfer coefficient, surroundings temperature, porosity, and particle diameter are presented and discussed.
Titania Nanoflowers with High Photocatalytic Activity
Authors: Wu Jin‐Ming , Huang Bing , Wang Min , Osaka Akiyoshi
Published: May 2006

Titania with nanostructures has attracted considerable attention due to its potential use in catalysts, gas sensors, photovoltaic cells, photonic crystals, etc. This paper reports the synthesis of titania nanoflowers by simply oxidizing pure titanium with hydrogen peroxide solutions containing hexamethylenetetramine and nitric acid at a low temperature of 353 K. Titania nanoflowers with the crystal structure of anatase or a mixture of anatase and rutile were obtained after a subsequent thermal treatment to crystallize the as‐precipitated amorphous structure. Photocatalytic tests revealed an excellent photocatalytic property of the titania nanoflowers.
Influence of Sterilization Techniques on the In Vitro Bioactivity of Pseudowollastonite
Authors: De Aza P. N. , De Aza A. H. , Herrera A. , Lopez‐Prats F. A. , Pena P.
Published: May 2006

The purpose of this study was to investigate the effect of four sterilization methods (Steam autoclave, Hydrogen peroxide plasma, Ethylene oxide, and Gamma sterilization) on the surface chemistry and in vitro bioactivity of polycrystalline pseudowollastonite (psW). psW samples obtained by solid‐state reaction sintering were sterilized and soaked in Kokubo et al.'s proposed simulated body fluid (SBF) up to 30 days. The sterilization procedure was found to result in no significant chemical changes in the surface of the samples. On the other hand, a Ca/P layer, of different thickness, identified as hydroxyapatite (HA) like, was developed on all the samples after soaking, although the Ethylene oxide‐sterilized samples present a non‐homogeneous and ∼68% thinner HA layer. The psW samples before soaking were analyzed by X‐ray diffraction, raman spectroscopy, and scanning electron microscopy (SEM). The interfacial reaction product was examined by SEM fitted with an energy‐dispersive X‐ray analyzer. Additionally, changes in ionic concentrations at the psW/SBF interface were measured.
Tin Oxide Nanoparticle‐Functionalized Multi‐Walled Carbon Nanotubes by the Vapor Phase Method
Authors: Fan Wugang , Gao Lian , Sun Jing
Published: May 2006

The vapor phase method was used to prepare tin oxide (SnO2)‐functionalized multi‐walled carbon nanotubes (MWNTs). SnO2 nanoparticles were uniformly decorated on the outer surface of MWNTs. At the same time, parts of the MWNTs can be filled with SnO2 nanoparticles. This simple technique is of interest for a distinct reacting process and efficiency.
Quantitative Analysis of Crystalline and Amorphous Phases in Glass–Ceramic Composites Like LTCC by the Rietveld Method
Authors: Kemethmüller Stefan , Roosen Andreas , Goetz‐Neunhoeffer Friedlinde , Neubauer Jürgen
Published: May 2006

Glass–ceramic composites like low‐temperature cofired ceramics are densified at temperatures below 900°C via liquid‐phase sintering. For high‐frequency applications, materials with low dielectric losses are needed. At these frequencies glass exhibits higher dielectric losses than a crystalline phase; therefore, the glass amount is reduced after densification by crystallization. To perform a quantitative X‐ray analysis of such glass–ceramic composites, a method based on Rietveld refinement was developed. For optimum results, the X‐ray diffraction patterns were fitted using the software TOPAS 2.1 from Bruker AXS. With this method, it is possible to determine quantitatively the amount of crystalline phases and also the amount of the remaining amorphous phase.
Spark Plasma Sintering Behavior of Nano‐Sized (Ba, Sr)TiO3 Powders: Determination of Sintering Parameters Yielding Nanostructured Ceramics
Authors: Liu Jing , Shen Zhijian , Nygren Mats , Su Bo , Button Tim W.
Published: May 2006

Nano‐powders of BaTiO3, SrTiO3, Ba0.6Sr0.4TiO3 (BST64), and a mixture of the composition (BaTiO3)0.6(SrTiO3)04 with particle sizes in the range of 60–80 nm were consolidated by spark plasma sintering (SPS). An experimental procedure is outlined that allows the determination of a “kinetic window,” defined as the temperature interval within which the densification process can be kinetically separated from the grain growth one, enabling preparation of dense nanostructured ceramics. The width of this window varied from almost zero for BST64 to 125°C for the (BaTiO3)0.6(SrTiO3)0.4 mixture. During the densification (sintering) of the (BaTiO3)0.6(SrTiO3)04 mixture, BST64 is formed. The main part of this reaction occurs in a fully densified body through which suggesting that the constitutional phase(s) have a self‐pinning effect on the grain growth.
Differences in the Placental Membrane Cytokine Response: a Possible explanation for the Racial Disparity in Preterm Birth
Authors: Menon Ramkumar , Merialdi Mario , Lombardi Salvatore J. , Fortunato Stephen J.
Published: May 2006

Problem

The prematurity rate is higher in African‐Americans (AA) compared with Caucasians (C). As spontaneous preterm labor has been hypothesized to be a host inflammatory response disease racial differences in human placental membrane inflammatory cytokine and prostaglandin pathway gene expression patterns between AA and C were examined in this report.

Method of study

Placental membranes (amniochorion) collected from AA and C women from cesareans at term were maintained in an organ explant system and stimulated with endotoxin (lipopolysaccharide, LPS). Microarray analysis and enzyme‐linked immunosorbent assay was performed on mRNAs and culture media from AA‐ and C‐derived membranes to document any differences in mRNA expression and protein production of IL‐1, IL‐6, IL‐8, IL‐10 and expression of cyclooxygenase 1 (COX‐1), COX‐2 and 15‐hydroxyprostaglandin dehydrogenase (PGDH).

Results

Increased mRNA expression of IL‐1, IL‐8 and COX‐2 in AA and IL‐6, IL‐10, COX‐1 and PGDH in C were documented after LPS stimulation. Concentration of IL‐1 was significantly higher in media derived from AA whereas IL‐6 and IL‐10 concentrations were higher in C with no differences observed in IL‐8 after LPS stimulation compared with respective unstimulated controls.

Conclusion

These data document ethnic diversity in placental membrane immune response.
Biochemical, molecular and behavioral phenotypes of Rab3A mutations in the mouse
Authors: Yang S. , Farias M. , Kapfhamer D. , Tobias J. , Grant G. , Abel T. , Bućan M.
Published: May 2006

Ras‐associated binding (Rab) protein 3A is a neuronal guanosine triphosphate (GTP)‐binding protein that binds synaptic vesicles and regulates synaptic transmission. A mouse mutant, earlybird (Ebd), with a point mutation in the GTP‐binding domain of Rab3A (D77G), exhibits anomalies in circadian behavior and homeostatic response to sleep loss. Here, we show that the D77G substitution in the Ebd allele causes reduced GTP and GDP binding, whereas GTPase activity remains intact, leading to reduced protein levels of both Rab3A and rabphilin3A. Expression profiling of the cortex and hippocampus of Ebd and Rab3a‐deficient mice revealed subtle differences between wild‐type and mutant mice. Although mice were backcrossed for three generations to a C57BL/6J background, the most robust changes at the transcriptional level between Rab3a−/− and Rab3a+/+ mice were represented by genes from the 129/Sv‐derived chromosomal region surrounding the Rab3a gene. These results showed that differences in genetic background have a stronger effect on gene expression than the mutations in the Rab3a gene. In behavioral tests, the Ebd/Ebd mice showed a more pronounced mutant phenotype than the null mice; Ebd/Ebd have reduced anxiety‐like behavior in the elevated zero‐maze test, reduced response to stress in the forced swim test and a deficit in cued fear conditioning (FC), whereas Rab3a−/− showed only a deficit in cued FC. Our data implicate Rab3A in learning and memory as well as in the regulation of emotion. A combination of forward and reverse genetics has provided multiple alleles of the Rab3a gene; our studies illustrate the power and complexities of the parallel analysis of these alleles at the biochemical, molecular and behavioral levels.
Complex, multimodal behavioral profile of the Homer1 knockout mouse
Authors: Jaubert P. J. , Golub M. S. , Lo Y. Y. , Germann S. L. , Dehoff M. H. , Worley P. F. , Kang S. H. , Schwarz M. K. , Seeburg P. H. , Berman R. F.
Published: May 2006

Proteins of the Homer1 immediate early gene family have been associated with synaptogenesis and synaptic plasticity suggesting broad behavioral consequences of loss of function. This study examined the behavior of male Homer1 knockout (KO) mice compared with wild‐type (WT) and heterozygous mice using a battery of 10 behavioral tests probing sensory, motor, social, emotional and learning/memory functions. KO mice showed mild somatic growth retardation, poor motor coordination, enhanced sensory reactivity and learning deficits. Heterozygous mice showed increased aggression in social interactions with conspecifics. The distribution of mGluR5 and N‐methyl‐d‐aspartate receptors (NMDA) receptors appeared to be unaltered in the hippocampus (HIP) of Homer1 KO mice. The results indicate an extensive range of disrupted behaviors that should contribute to the understanding of the Homer1 gene in brain development and behavior.
Nitric oxide and ovarian function
Authors: HATTORI Masa‐aki , TABATA Shoji
Published: May 2006

Nitric oxide (NO) is synthesized by three NO synthases, designated as NOS‐1, NOS‐2, and NOS‐3, with distinct features and localization. Nitric oxide and the reactive oxygen species generated from NO react with a wide variety of biomolecules such as DNA, transcription factors, enzymes, cytokines, and membrane receptors in NO synthesized cells and nearby cells to mediate a variety of biological functions. Nitric oxide synthase‐2 and NOS‐3 are expressed in the ovary during folliculogenesis and luteinization. Nitric oxide functions as an important modulator for folliculogenesis and atresia, steroidogenesis, prostaglandin biosynthesis, ovulation, luteolysis, and oocyte maturation. Nitric oxide synthase‐3 is also localized in the porcine oocytes of the primordial follicles as well as in large follicles. It has been proved that NO is involved in intracellular signaling for oocyte growth and maturation at the pre‐ovulatory stage.
Comparison of in vitro digestibility and chemical composition among sugarcane bagasses treated by four white‐rot fungi
Authors: OKANO Kanji , IIDA Yuko , SAMSURI Muhammad , PRASETYA Bambang , USAGAWA Tomoya , WATANABE Takashi
Published: May 2006

The capabilities of four white‐rot fungi to improve the digestibility of sugarcane bagasse for ruminants were determined. Bagasse was cultured with Lentinula edodes, Pleurotus eryngii, Pleurotus salmoneostramineus, Ceriporiopsis subvermispora (ATCC 90467) or C. subvermispora (CZ‐3) at 26°C for 8, 12 or 16 weeks. The in vitro organic matter digestibility (IVOMD) and in vitro neutral detergent fiber digestibility (IVNDFD) in untreated bagasse were 45.6 and 40.3%, respectively. Meanwhile, the bagasse cultured with L. edodes and two strains of C. subvermispora, respectively, for 12 weeks, were elevated to 68.6 and 59.1%, 60.6 and 49.9% and 59.9 and 49.0%, respectively. In contrast, the IVOMD and the IVNDFD in bagasse cultured with P. eryngii and P. salmoneostramineus were the same or lower than those in untreated bagasse. In vitro gas production (IVGP) in bagasse cultured with L. edodes and two strains of C. subvermispora for 12 weeks was also higher than that of untreated bagasse. These changes in IVOMD, IVNDFD and IVGP demonstrate that L. edodes has a higher capability of improving the digestibility for ruminants than C. subvermispora, P. eryngii or P. salmoneostramineus.
The effect of fermented persimmon shell diet supplementation on the growth performance and blood parameters in finishing pigs
Authors: KIM Hoi‐Yun , SONG Young‐Min , KANG Yang‐Su , KIM Chung‐Hui , LEE Sung‐Dae , CHOWDAPPA Rekha , HA Ji‐Hee , KANG Seoc‐Mo
Published: May 2006

The objective of the present study was to investigate the effects of fermented persimmon shell diet (FPSD) supplementation on growth performance and blood parameters in 96 Berkshire pigs. The FPSD was made from persimmon shell and mixed with rice bran and barley bran. Samples of FPSD on day 0 (D0) and day 60 (D60) were analyzed for chemical composition, pH and organic acids. The experimental diets were 0, 3, 5 and 7% FPSD added to C, T1, T2 and T3 of finishing diets on fresh matter basis. Dry matter (DM) was lower (P < 0.01) and crude protein was higher (P < 0.01) on D60 than on D0. pH value decreased (P < 0.01) on D60 than on D0 but organic acids were increased (P < 0.01). Average daily gain was higher (P < 0.05) in T2 than in other groups. Average daily feed intake was higher (P < 0.05) in T2 than in other groups. Total cholesterol was higher (P < 0.05) in T3 than in other groups. High‐density lipoprotein cholesterol increased (P < 0.05) in groups by the addition of FPSD. Blood urea nitrogen was lower (P < 0.05) in C than in other groups. The results indicate that FPSD improved the growth performance and blood parameters in Berkshire pigs.
Temporal expression of growth factor genes of primary porcine satellite cells during myogenesis
Authors: THEIL Peter K. , SØRENSEN Inge L. , NISSEN Pia M. , OKSBJERG Niels
Published: May 2006

The present experiment was undertaken to study the transcription of members of the insulin‐like growth factor (IGF) system and myostatin in porcine satellite cells through myogenesis and to study the effects of 1 µmol/L insulin on stimulating fusion. Cultured cells were harvested at 50 and 80% confluence and at days 1, 2, 3 and 4 following induction of fusion and differentiation. Increased levels of myogenin transcription and creatine kinase from 50% confluence until day 2 indicated that fusion and differentiation were induced. The mRNA abundance of IGF‐I (P < 0.001), IGF‐II (P < 0.001), IGF binding protein (BP) 5 (P < 0.01), type I IGF receptor (P < 0.001) and myostatin (P < 0.01) increased from proliferation to differentiation. Insulin stimulated differentiation as indicated by elevated creatine kinase activity (P < 0.001) but did not affect myogenin mRNA abundance (P = 0.98). Insulin downregulated transcription of IGF‐I (P < 0.01) and during the first 2 days after switching to differentiation medium insulin downregulated IGF receptor transcription (P < 0.001), whereas insulin did not affect transcription of IGF‐II (P = 0.06), IGFBP5 (P = 0.76) or myostatin (P = 0.50). In conclusion, transcriptions of IGF‐I, IGF‐II, type I IGF receptor, IGFBP5 and myostatin were changed during myogenesis, suggesting autocrine/paracrine roles in regulating the transition from proliferation to differentiation of porcine satellite cells.
Decrease in stearic acid proportions in adipose tissues and liver lipids in fatty liver of dairy cows
Authors: SATO Hiroshi , INOUE Aya
Published: May 2006

Samples of liver and perirenal, mesenteric and subcutaneous fat were collected from 16 sick necropsied dairy cows to evaluate the fatty acid profiles in the hepatic and adipose tissues associated with advanced fatty liver or hepatic lipidosis. Hepatic triglyceride and eight fatty acids were measured in the hepatic and adipose tissues. Six cows had more than 3% triglyceride on fresh weight in their livers and were classified as having fatty liver. Stearic and linoleic acid proportions in the liver decreased markedly with increased hepatic triglyceride levels, while the proportion of palmitic and oleic acids increased. The most striking fluctuations in hepatic lipidosis were manifested as decreased stearic acid in the adipose tissues including subcutaneous fat with the trend of decreasing stearic acid. Palmitic acid was elevated in hepatic and perirenal fat in fatty liver cows. In instances of advanced hepatic lipidosis, palmitoleic acid increased in only subcutaneous fat and not in perirenal or mesenteric fat. In addition to the proportions of hepatic fatty acids in fatty liver, this study also clarified the fluctuations observed in the profiles of fatty acids of the adipose tissues in cows with advanced hepatic lipidosis, particularly the decline in the proportions of stearic acid.
Regional heterogeneity in the developing palate: morphological and molecular evidence for normal and abnormal palatogenesis
Authors: Okano Junko , Suzuki Shigehiko , Shiota Kohei
Published: May 2006

ABSTRACT  Development of the mammalian secondary palate involves the growth, elevation, medial elongation and midline fusion of palatal shelves. Recent morphological and molecular studies on palatogenesis suggest that the developing palate is not a homogeneous organ but each part may behave differently during organogenesis. Especially, some key molecules involved in palate development have been shown to exhibit heterogeneous patterns of expression in the palatal tissue. Therefore it seems necessary to recognize the regional heterogeneity of the developing palate along the dorsoventral and anteroposterior axes when analyzing the mechanisms of normal and abnormal morphogenesis. Based on recent studies, we discuss the issue of the regional heterogeneity in the fetal palate and propose a principle that divides the fetal palate into several regions from the morphological and molecular standpoint.
Etiology, pathogenesis and prevention of neural tube defects
Authors: Padmanabhan Rengasamy
Published: May 2006

ABSTRACT  Spina bifida, anencephaly, and encephalocele are commonly grouped together and termed neural tube defects (NTD). Failure of closure of the neural tube during development results in anencephaly or spina bifida aperta but encephaloceles are possibly post‐closure defects. NTD are associated with a number of other central nervous system (CNS) and non‐neural malformations. Racial, geographic and seasonal variations seem to affect their incidence. Etiology of NTD is unknown. Most of the non‐syndromic NTD are of multifactorial origin. Recent in vitro and in vivo studies have highlighted the molecular mechanisms of neurulation in vertebrates but the morphologic development of human neural tube is poorly understood. A multisite closure theory, extrapolated directly from mouse experiments highlighted the clinical relevance of closure mechanisms to human NTD. Animal models, such as circle tail, curly tail, loop tail, shrm and numerous knockouts provide some insight into the mechanisms of NTD. Also available in the literature are a plethora of chemically induced preclosure and a few post‐closure models of NTD, which highlight the fact that CNS malformations are of hetergeneitic nature. No Mendelian pattern of inheritance has been reported. Association with single gene defects, enhanced recurrence risk among siblings, and a higher frequency in twins than in singletons indicate the presence of a strong genetic contribution to the etiology of NTD. Non‐availability of families with a significant number of NTD cases makes research into genetic causation of NTD difficult. Case reports and epidemiologic studies have implicated a number of chemicals, widely differing therapeutic drugs, environmental contaminants, pollutants, infectious agents, and solvents. Maternal hyperthermia, use of valproate by epileptic women during pregnancy, deficiency and excess of certain nutrients and chronic maternal diseases (e.g. diabetes mellitus) are reported to cause a manifold increase in the incidence of NTD. A host of suspected teratogens are also available in the literature. The UK and Hungarian studies showed that periconceptional supplementation of women with folate (FA) reduces significantly both the first occurrence and recurrence of NTD in the offspring. This led to mandatory periconceptional FA supplementation in a number of countries. Encouraged by the results of clinical studies, numerous laboratory investigations focused on the genes involved in the FA, vitamin B12 and homocysteine metabolism during neural tube development. As of today no clinical or experimental study has provided unequivocal evidence for a definitive role for any of these genes in the causation of NTD suggesting that a multitude of genes, growth factors and receptors interact in controlling neural tube development by yet unknown mechanisms. Future studies must address issues of gene‐gene, gene‐nutrient and gene–environment interactions in the pathogenesis of NTD.
Rates for specific birth defects among offspring of Japanese mothers, Hawaii, 1986–2002
Authors: Forrester Mathias B. , Merz Ruth D.
Published: May 2006

ABSTRACT  The objective of this investigation was to identify the rates for specific birth defects among the offspring of Japanese mothers in Hawaii and compare them to rates among the offspring of white mothers. Cases were all infants and fetuses with any of 54 specific birth defects born to Japanese and white mothers identified by a population‐based birth defects registry in Hawaii. The rates were calculated for both racial groups and comparisons made by calculating the rate ratio and 95% confidence interval. The rates among the offspring of Japanese mothers were substantially higher for four of the birth defects (pulmonary valve atresia and stenosis, anomalous pulmonary venous return, cleft lip with/without cleft palate, small intestinal atresia and stenosis) and substantially lower for five of the birth defects (pyloric stenosis, hypospadias and epispadias, renal agenesis and hypoplasia, obstructive genitourinary defect, syndactyly). After adjusting for maternal age, these significantly elevated or lower rates remained. Moreover, the rate was significantly higher among the offspring of Japanese mothers for anotia/microtia, tetralogy of Fallot, and persistent cloaca and significantly lower for transposition of great arteries. The rates for a number of specific birth defects differed between Japanese and white mothers in Hawaii.
Inhibition of recombinant human maltase glucoamylase by salacinol and derivatives
Authors: Rossi Elena J. , Sim Lyann , Kuntz Douglas A. , Hahn Dagmar , Johnston Blair D. , Ghavami Ahmad , Szczepina Monica G. , Kumar Nag S. , Sterchi Erwin E. , Nichols Buford L. , Pinto B. M. , Rose David R.
Published: May 2006

Inhibitors targeting pancreatic α‐amylase and intestinal α‐glucosidases delay glucose production following digestion and are currently used in the treatment of Type II diabetes. Maltase‐glucoamylase (MGA), a family 31 glycoside hydrolase, is an α‐glucosidase anchored in the membrane of small intestinal epithelial cells responsible for the final step of mammalian starch digestion leading to the release of glucose. This paper reports the production and purification of active human recombinant MGA amino terminal catalytic domain (MGAnt) from two different eukaryotic cell culture systems. MGAnt overexpressed in Drosophila cells was of quality and quantity suitable for kinetic and inhibition studies as well as future structural studies. Inhibition of MGAnt was tested with a group of prospective α‐glucosidase inhibitors modeled after salacinol, a naturally occurring α‐glucosidase inhibitor, and acarbose, a currently prescribed antidiabetic agent. Four synthetic inhibitors that bind and inhibit MGAnt activity better than acarbose, and at comparable levels to salacinol, were found. The inhibitors are derivatives of salacinol that contain either a selenium atom in place of sulfur in the five‐membered ring, or a longer polyhydroxylated, sulfated chain than salacinol. Six‐membered ring derivatives of salacinol and compounds modeled after miglitol were much less effective as MGAnt inhibitors. These results provide information on the inhibitory profile of MGAnt that will guide the development of new compounds having antidiabetic activity.
A novel N‐terminal hydrophobic motif mediates constitutive degradation of serum‐ and glucocorticoid‐induced kinase‐1 by the ubiquitin–proteasome pathway
Authors: Bogusz Agata M. , Brickley Deanna R. , Pew Travis , Conzen Suzanne D.
Published: May 2006

Serum‐ and glucocorticoid‐induced protein kinase‐1 (SGK‐1) plays a critical role in regulation of the epithelial sodium channel, ENaC. SGK‐1 also shares significant catalytic domain homology with protein kinase B (PKB/AKT‐1) and is a downstream effector of antiapoptotic phosphoinositide 3‐kinase signaling. Steady‐state levels of an active SGK‐1 are tightly regulated by rapid transcriptional activation and post‐translational modification including phosphorylation. We show here that endogenous SGK‐1 protein is polyubiquitinated and rapidly degraded by the 26S proteasome. In contrast to other rapidly degraded kinases, neither the catalytic activity of SGK‐1 nor activation site phosphorylation was required for its ubiquitin modification and degradation. Instead, SGK‐1 degradation required a lysine‐less six‐amino‐acid (amino acids 19–24) hydrophobic motif (GMVAIL) within the N‐terminal domain. Deletion of amino acids 19–24 significantly increased the half‐life of SGK1 and prevented its ubiquitin modification. Interestingly, this minimal region was also required for the association of SGK‐1 with the endoplasmic reticulum. Ubiquitin modification and degradation of SGK‐1 were increasingly inhibited by the progressive mutation of six N‐terminal lysine residues surrounding the GMVAIL motif. Mutation of all six lysines to arginine did not disrupt the subcellular localization of SGK‐1 despite a significant decrease in ubiquitination, implying that this modification per se was not required for targeting to the endoplasmic reticulum. These results suggest that constitutive ubiquitin‐mediated degradation of SGK‐1 is an important mechanism regulating its biological activity.
The Practical Use of Simplicity in Developing Ground Water Models
Authors: Hill Mary C.
Published: May 2006

The advantages of starting with simple models and building complexity slowly can be significant in the development of ground water models. In many circumstances, simpler models are characterized by fewer defined parameters and shorter execution times. In this work, the number of parameters is used as the primary measure of simplicity and complexity; the advantages of shorter execution times also are considered. The ideas are presented in the context of constructing ground water models but are applicable to many fields. Simplicity first is put in perspective as part of the entire modeling process using 14 guidelines for effective model calibration. It is noted that neither very simple nor very complex models generally produce the most accurate predictions and that determining the appropriate level of complexity is an ill‐defined process. It is suggested that a thorough evaluation of observation errors is essential to model development. Finally, specific ways are discussed to design useful ground water models that have fewer parameters and shorter execution times.
Gender Matters: Ethnographers Bring Gender from the Periphery toward the Core of Migration Studies
Authors: Mahler Sarah J. , Pessar Patricia R.
Published: May 2006

Ethnographers from anthropology, sociology, and other disciplines have been at the forefront of efforts to bring gender into scholarship on international and transnational migration. This article traces the long and often arduous history of these scholars' efforts, arguing that though gender is now less rarely treated merely as a variable in social science writing on migration, it is still not viewed by most researchers in the field as a key constitutive element of migrations. The article highlights critical advances in the labor to engender migration studies, identifies under-researched topics, and argues that there have been opportunities when, had gender been construed as a critical force shaping migrations, the course of research likely would have shifted. The main example developed is the inattention paid to how gendered recruitment practices structure migrations – the fact that gender sways recruiters' conceptions of appropriate employment niches for men versus women.
Geographies of Gender and Migration: Spatializing Social Difference
Authors: Silvey Rachel
Published: May 2006

This article provides a review of the contributions that the discipline of geography is making to gender and migration research. In geographic analyses of migration, gender differences are examined most centrally in relation to specific spatialities of power. In particular, feminist geographers have developed insight into the gender dimensions of the social construction of scale, the politics of interlinkages between place and identity, and the socio-spatial production of borders. Supplementing recent reviews of the gender and migration literature in geography, this article examines the potential for continued cross-fertilization between feminist geography and migration research in other disciplines. The advances made by feminist geographers to migration studies are illustrated through analysis of the findings and debates tied to the subfield's central recent conceptual interventions.
Gender and Migration: Historical Perspectives
Authors: Sinke Suzanne M.
Published: May 2006

Gender has become a category of concern for many historians of migration in scholarship of the 2000s. This article notes a variety of factors which made it possible and likely for historians to turn to questions of gender. The article surveys historiography on migration and gender as it developed in the late twentieth century and explores some current directions in this scholarship, on a variety of geographic scales: global, national, and local. It emphasizes the need for longitudinal analysis in any study of gender and migration, and notes some approaches to the concept of time used by historians.
Gender, Migration, and Law: Crossing Borders and Bridging Disciplines
Authors: Calavita Kitty
Published: May 2006

The gendered nature of the immigration experience is shaped and reinforced by law, legal consciousness, and the normative understandings they help constitute. This article provides an overview of the role of gender in migration processes from a law and society perspective, and includes an empirical focus on the new immigration to Italy and Spain as an illustration of the utility of such an approach. Beginning with a brief summary of the literatures of feminist jurisprudence and law and migration, respectively, the small body of scholarship at the intersection of these fields is reviewed. The author then examines the new immigration to Italy and Spain and argues that this immigration and the policies that shape it highlight the role of the state in gendering immigrant labor and offer new angles from which to consider the interplay of gender, race, migration status, and marginality. In concluding, the author proposes that such exploration of immigrants' experiences in southern Europe reveals the surprising complexity of immigrants' multiple marginalities, and exposes the powerful contingencies of economic context, prevailing stereotypes, the particulars of state policy, and the agentive power of people struggling to survive.
Gendering the Politics of Migration
Authors: Piper Nicola
Published: May 2006

Although every aspect of the migration process is shaped by political factors and migration presents many political challenges on the domestic and international levels, the attention of political scientists in the United States and Europe has been limited to relatively few topics, including control over entry and exit, and issues of incorporation and citizenship. Work that considers the political aspects of migration from a gender perspective constitutes an even smaller body of work. In considering the contribution that political science might make to our understanding of gendered migration, this essay points both to some pioneering studies of gendered patterns of migration and incorporation, and also to the growing concern with gender among international organizations and policy makers. Interestingly, the essay shows that it is scholars in neighboring disciplines who have more often have taken up questions of governance and the development of gender-fair policy towards migrants. The essay raises questions about the relationship between disciplinary boundaries and topical areas and also about the ways in which regional contexts shape the nature of scholarly inquiry by contrasting work on Asia with that in Europe and the United States.
Gendered Perspectives in Psychology: Immigrant Origin Youth
Authors: Suárez-Orozco Carola , Qin Desirée Baolian
Published: May 2006

In this article, we contend that the field of psychology has largely failed to foreground the role of gender in its study of immigration. Here, we review studies that address gender and migration focusing on the experience of children and adolescents. We provide developmental perspectives on family relations, well-being, identity formation, and educational outcomes, paying particular attention to the role of gender in these domains. We conclude with recommendations for future research, which include the need to consider whether, and if so, how, when, and why it makes a difference to be an immigrant, to be from a particular country, or to be female rather than male. We argue that it is important to consider socioeconomic characteristics; to consider resilience as well as pathology; and to work in interdisciplinary ways to deepen our understanding of the gendered migratory experience of immigrant origin youth.
Mapping Gender and Migration in Sociological Scholarship: Is It Segregation or Integration?
Authors: Curran Sara R. , Shafer Steven , Donato Katharine M. , Garip Filiz
Published: May 2006

A review of the sociological research about gender and migration shows the substantial ways in which gender fundamentally organizes the social relations and structures influencing the causes and consequences of migration. Yet, although a significant sociological research has emerged on gender and migration in the last three decades, studies are not evenly distributed across the discipline. In this article, we map the recent intellectual history of gender and migration in the field of sociology and then systematically assess the extent to which studies on engendering migration have appeared in four widely read journals of sociology (American Journal of Sociology, American Sociological Review, Demography, and Social Forces). We follow with a discussion of these studies, and in our conclusions, we consider how future gender and migration scholarship in sociology might evolve more equitably.
Changes in contractile properties of motor units of the rat medial gastrocnemius muscle after spinal cord transection
Authors: Celichowski Jan , Mrówczyński Włodzimierz , Krutki Piotr , Górska Teresa , Majczyński Henryk , Sławińska Urszula
Published: May 2006

The effects of complete transection of the spinal cord at the level of Th9/10 on contractile properties of the motor units (MUs) in the rat medial gastrocnemius (MG) muscle were investigated. Our results indicate that 1 month after injury the contraction time (time‐to‐peak) and half‐relaxation time were prolonged and the maximal tetanic force in most of the MUs in the MG muscle of spinal rats was reduced. The resistance to fatigue also decreased in most of the MUs in the MG of spinal animals. Moreover, the post‐tetanic potentiation of twitches in MUs diminished after spinal cord transection. Criteria for the division of MUs into three types, namely slow (S), fast fatigue resistant (FR) and fast fatigable (FF), applied in intact animals, could not be directly used in spinal animals owing to changes in contractile properties of MUs. The ‘sag’ phenomenon observed in unfused tetani of fast units in intact animals essentially disappeared in spinal rats and it was only detected in few units, at low frequencies of stimulation only. Therefore, the MUs in spinal rats were classified as fast or slow on the basis of an adjusted borderline of 20 ms, instead of 18 ms as in intact animals, owing to a slightly longer contraction time of those fast motor units with the ‘sag’. We conclude that all basic contractile properties of rat motor units in the medial gastrocnemius muscle are significantly changed 1 month after complete spinal cord transection, with the majority of motor units being more fatigable and slower than those of intact rats.
Gut myoelectrical activity induces heat shock response in Escherichia coli and Caco‐2 cells
Authors: Laubitz Daniel , Jankowska Alicja , Sikora Anna , Woliński Jarosław , Zabielski Romuald , Grzesiuk Elżbieta
Published: May 2006

The heat shock response is associated with the intracellular expression of a number of highly conserved heat shock proteins (Hsps). According to their molecular size, Hsps have been divided into several groups, which are strongly conserved and show high homology between the species, e.g., Hsp70, MW 70 kDa (Lindquist & Craig, 1998; Morimoto, 1998; Jolly & Morimoto, 2000; Żylicz et al. 2001). In all organisms the Hsp expression under stress conditions is regulated at transcriptional level, e.g., in humans by the heat shock transcription factor Hsf1 (Morimoto, 1998; Wu, 1995), while in Escherichia coli by replacement of the sigma factor σ70 in RNA polymerase by the sigma factor σ32 (Gross, 1987). The Hsps allow cell survival under stress conditions by renaturating of denaturated proteins, protecting of stress‐labile proteins, preventing protein aggregation (chaperone functions), and by degradation of damaged proteins (protease activities) (Lindquist & Craig, 1988; Morimoto, 1998; Jolly & Morimoto, 2000). They have also many housekeeping functions under non‐stressful conditions during the cell cycle, growth, development, and differentiation (Morimoto, 1998). Among a number of plausible inducing factors already studied, extremely low artificial electromagnetic fields have been shown to induce stress response in various cells, such as expression of σ32 mRNA (Cairo et al. 1998) and induction of DnaJ and DnaK proteins in Eschericha coli (Chow & Tung, 2000); expression of hsp‐16 gene in Caenorhabditis elegans (Miyakawa et al., 2001); induction of heat shock transcription factor Hsf1 and Hsp70, Hsp90 and Hsp27 in human cells (Lin et al. 1997; Lin et al. 1998; Goodman & Blank, 1998; Pipkin et al. 1999). Nevertheless, the role of endogenous electromagnetic fields, i.e., generated by electrically active cells within a body remains controversial. Heat shock proteins (Hsps) protect cells against various environmental and endogenous stressors. Cytoprotection caused by Hsps involves tolerance induced by one agent against other, more severe agents. We have found that exposure of prokaryotic (Escherichia coli) and eukaryotic (Caco‐2) cells to an electrical field (EF) connected with a myoelectrical migrating complex (MMC) generated by the small intestine smooth muscle induces the heat shock response. Using Western blot analysis, we have detected an elevated level of sigma factor 32 in E. coli cells exposed to MMC‐related EF, and confocal microscopy indicated an increased level of the inducible form of Hsp70 protein in EF‐stimulated Caco‐2 cells. Additionally, we have found that this induced level of Hsp70 protected the Caco‐2 cells against apoptosis caused by camptothecin. Our observations suggest that the myoelectrical activity of the gut may induce heat shock mechanisms in the cells of gut epithelium as well as in gastrointestinal micro‐organisms.
Modulation of systemic and renal haemodynamics by κ‐opioids in conscious lambs
Authors: Qi Wei , Smith Francine G.
Published: May 2006

The purpose of the present study was to determine the cardiovascular effects of the κ‐opioid receptor agonist U‐50488H at two stages of postnatal maturation under physiological conditions. Experiments were carried out firstly to define systemic and renal haemodynamic responses to κ‐opioid receptor activation and, secondly, to determine whether these effects are altered during postnatal maturation. To investigate whether the responses to U‐50488H resulted from receptor‐dependent effects, responses to U‐50488H were also tested in the presence of the specific κ‐opioid receptor antagonist 5′‐guanidinonaltrindole (GNTI). Experiments were carried out in two groups of conscious, chronically instrumented lambs aged ∼1 and ∼6 weeks. Mean arterial pressure, mean venous pressure and renal blood flow (RBF) were measured for 30 min before and 90 min after i.v. injection of U‐50488H or vehicle. Heart rate increased in both age groups of lambs within 10 min of U‐50488H administration. Mean arterial pressure decreased for 50 min following U‐50488H administration at 1 week but, in contrast, increased transiently at 10 min in 6‐week‐old lambs, returning to control levels by 20 min. In both age groups, there was a sustained decrease in RBF following U‐50488H. The aforementioned responses to U‐50488H were abolished by pretreatment with GNTI. These data provide the first measurements of systemic and renal haemodynamic responses to κ‐opioid receptor activation during postnatal maturation.