bluuebunny/crossref_metadata_2025 huggingface dataset:
Regeneration in planarians and other worms: New findings, new tools, and new perspectives
Authors: Saló Emili , Baguñà Jaume
Published: August 2002

Molecular biology, recombinant DNA techniques, and new methods of cell lineage have reignited the interest of planarians and other worms (mainly annelids and nemerteans) as invertebrate model systems of regeneration. Here, the mean results produced in the last five years are reviewed, an update of the genes and molecules involved in planarian regeneration is provided, and a new morphallactic‐epimorphic model of pattern formation is suggested. Moreover, and most importantly, we highlight the new strides brought upon by genomic/proteomic analyses, RNA interference (RNAi) to inactivate gene function, and Bromodeoxyuridine (BrdU) cell labelling. The raising hope to obtain transformed neoblasts and transgenic planarians is also stressed. Altogether, such approaches will eventually lead to solve the long‐standing open questions on regeneration which still baffles us. Finally, we warn against overlooking the evident links between regeneration processes and those controlling the daily wear and tear of tissues and cells. Both processes act, at least in planarians, upon a unique stem‐cell endowed with an unrivaled developmental potential in the animal kingdom—the neoblast. This cell could be considered the forebear and a model system for stem‐cell analysis. J. Exp. Zool. 292:528–539, 2002. © 2002 Wiley‐Liss, Inc.
The use of low‐molecular‐weight PEIs as gene carriers in the monkey fibroblastoma and rabbit smooth muscle cell cultures
Authors: Lampela Pasi , Räisänen Johanna , Männistö Pekka T. , Ylä‐Herttuala Seppo , Raasmaja Atso
Published: August 2002

Background

Polyethylenimines (PEIs) and cationic polymers have been used successfully in gene delivery. In earlier reports, only large PEIs (MW>10 000) have shown significant transfection efficiency. In the present study, the roles of small PEIs (MW 700 and 2000) were studied as additional compounds to see if they can improve gene delivery with cationic liposomes.

Methods

The TKBPVlacZ expression plasmid was transfected in the CV1‐P (monkey fibroblastoma) and SMC (rabbit smooth muscle) cell lines using various combinations of PEIs (MW 700, 2000, and 25 000) and Dosper liposomes. The transfection efficiency was determined with the fluorometric ONPG (o‐nitrophenol‐β‐D‐galactopyranoside) assay and histochemical X‐gal staining. The toxicity of the transfection reagents was estimated by the MTT [3‐(4,5‐dimethylthiazolyl‐2)‐2,5‐diphenyl tetrazolium bromide] assay.

Results

Transfection of TKBPVlacZ plasmid by the small PEIs (MW 700 and 2000) combined with Dosper liposomes was associated with high expression of the lacZ reporter gene in the CV1‐P and SMC cell lines. The transfection efficiencies of the low‐molecular‐weight PEI/liposome combinations were several fold higher than those of PEIs or liposomes alone. PEI/liposome combinations had no toxicity on the cell lines tested.

Conclusions

The low‐molecular‐weight PEIs could be used successfully for gene delivery when combined with the cationic liposomes, resulting in a synergistic increase of the transfection efficiency in both cell lines studied. Copyright © 2002 John Wiley & Sons, Ltd.
Total choosability of multicircuits I
Authors: Kostochka Alexandr V. , Woodall Douglas R.
Published: August 2002

A multicircuit is a multigraph whose underlying simple graph is a circuit (a connected 2‐regular graph). In this pair of papers, it is proved that every multicircuit C has total choosability (i.e., list total chromatic number) ch′′(C) equal to its ordinary total chromatic number χ′′(C). In the present paper, the kernel method is used to prove this for every multicircuit that has at least two vertices with degree less than its maximum degree Δ. The result is also proved for every multicircuit C for which χ′′(C)≥Δ+2. © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 26–43, 2002
The improved biological properties in mice of 99mTc–TBI for myocardial perfusion imaging
Authors: Zhang X. Zh. , Wang X. B. , Tang Z. G.
Published: August 2002

The aim of this study was to improve the biological properties of 99mTc–TBI complex for myocardial perfusion imaging. The effect of Tween‐80 on the biodistribution in mice of 99mTc–TBI was reported. The experimental results show that liver and blood uptakes of Tween‐80 added (TA) complex are significantly lower than those of corresponding non‐Tween‐80 added (NTA) complex. Also, the clearance rate from blood of TA complex is faster than that of NTA complex. At 60 min post‐injection time, the ratios of heart‐to‐liver, heart‐to‐lung and heart‐to‐blood were 1.29, 137.75 and 4.73, respectively, for the TA complex; however, the corresponding ratios were 0.57, 13.07 and 2.65, respectively, for NTA complex. The biodistribution in mice of the Tween‐80 added 99mTc–TBI (99mTc–TBI(T)) is comparable with the widely used myocardial perfusion imaging agent 99mTc–MIBI in some aspects; especially, the heart‐to‐liver ratios of 99mTc–TBI(T) at various post‐injection times are better than those of 99mTc–MIBI. The biological properties of 99mTc–TBI complex for myocardial imaging were improved significantly by using Tween‐80 as an auxiliary agent. It is worthy of further studies. Copyright © 2001 John Wiley & Sons, Ltd.
Safety aspects and quality assessment in MRI and MRS: A challenge for health care systems in Europe
Authors: de Certaines Jacques D. , Cathelineau Guy
Published: August 2002

Despite advances in international cooperation, the application of the safety regulations of different countries remains an important challenge for manufacturers and health care workers in the European Union. Rapid technological development during the last 20 years, and the still controversial nature of certain potential effects of magnetic or electromagnetic fields, make the task particularly difficult for MRI and MRS. As the relevant literature is rather extensive, the present work will limit its goals to four questions: 1) How is MRI and MRS safety regulation managed within the European Union? 2) Concerning direct potential physiological effects, what is presently well known and controlled, and, conversely, what are the remaining open (and often controversial) questions? 3) As metallic implants are probably the main risk in routine MRI, what regulatory strategy is in progress in Europe? 4) As indirect risks related to artifacts must not be underestimated, what European programs have been developed for quality assessment in MRI and MRS? In all of these fields, evidence is provided demonstrating the need for a mutual recognition of common standards for the European Union and the United States. J. Magn. Reson. Imaging 2001;13:632–638. © 2001 Wiley‐Liss, Inc.
Gas‐phase conversion of tetrazoles to oxadiazoles: isolation and characterization of the N‐acylated intermediate
Authors: Seldes A. M. , D'Accorso N. , Souto M. F. , Martins Alho M. , Arabehety C. G.
Published: August 2002

The 5‐substituted tetrazole ring was reacted in the gas phase with an acyl ion generated as the secondary reactive chemical ionization plasma in the mass spectrometer. The product ions obtained, among others, were proposed as the rearranged 2,5‐disubstituted‐1,3,4‐oxadiazole nucleus. Its structure was demonstrated by comparison of the product ion spectrum of the 2,5‐disubstituted‐1,3,4‐oxadiazole derivative obtained by condensed‐phase reaction and the product ion spectrum of the oxadiazole derivative generated in situ by reaction of the 5‐substituted tetrazole derivative with the acyl plasma. It was proposed that the mechanism of this transformation involved the presence of an acylated tetrazole intermediary, which could not be isolated in the condensed phase, followed by the rearrangement, with nitrogen loss, to afford the oxadiazole derivative. Under our conditions we were able to isolate the intermediate ion in the first field free region and demonstrate its structure by collision induced dissociation–tandem mass spectrometry. Copyright © 2001 John Wiley & Sons, Ltd.
Measles virus strains circulating in Ethiopia in 1998–1999: Molecular characterisation using oral fluid samples and identification of a new genotype
Authors: Nigatu W. , Jin L. , Cohen B.J. , Nokes D.J. , Etana M. , Cutts F.T. , Brown D.W.G.
Published: August 2002

A measles outbreak in December 1998 in Bedelle (vaccine coverage <40%) and two sporadic cases in Addis Ababa, Ethiopia, were investigated. Paired serum and oral fluid samples were collected 2–8 days after the onset of symptoms. A total of 53 of 55 outbreak cases and both sporadic cases were positive for serum measles virus‐specific IgM. Oral fluid measles‐specific IgM was positive in 71% of cases collected up to 5 days after onset and in 90% collected at 6–8 days. By contrast, 100% of oral fluid samples were positive for measles virus RNA by RT‐PCR, suggesting that early collection of samples favoured the detection of measles virus RNA by RT‐PCR. The measles virus strain in the outbreak was identified as genotype D4. One strain from a sporadic case was also genotype D4; the strain from the other sporadic case was assigned to clade D but was distinct. The degree of divergence from recognised clade D strains suggested that, together with three strains from the United Kingdom, it represents an additional genotype of clade D (GenBank accession numbers AF280800–280807). J. Med. Virol. 65:373–380, 2001. © 2001 Wiley‐Liss, Inc.
Glutamate activates PP125FAK through AMPA/kainate receptors in Bergmann glia
Authors: Millán Alejandro , Aguilar Pablo , Méndez J. Alfredo , Arias‐Montaño José‐Antonio , Ortega Arturo
Published: August 2002

Glial glutamate receptors are likely to play a role in plasticity, learning, and memory and in a number of neuropathologies. An enhanced glutamate‐dependent tyrosine phosphorylation has been detected in such processes. Using primary cultures of chick Bergmann glia cells and chick cerebellar slices, we addressed whether glial glutamate receptors can activate the nonreceptor tyrosine kinase pp125 focal adhesion kinase (pp125FAK). A dose‐ and time‐dependent tyrosine phosphorylation of pp125FAK was found in both preparations upon glutamate treatment. This effect was mediated through α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoaxazolepropionate (AMPA)/kainate (KA) receptors, as shown by its inhibition by the specific antagonists 2,3‐dioxo‐6‐nitro‐1,2,3,4‐tetrahydrobenzo[f]quinoxaline‐7‐ sulfonamide (NBQX) and 6,7‐dinitroquinoxaline‐2,3‐dione (DNQX) and the lack of effect of metabotropic agonists. FAK tyrosine phosphorylation was dependent on phosphatidylinositol 3‐kinase activity. As expected, an increase in pp125FAK catalytic activity was found upon glutamate treatment. Immunprecipitation experiments demonstrated that FAK associates with ionotropic glutamate receptors. Taken together, these results suggest a role for glial glutamate receptors in cytoskeletal rearrengments and focal adhesion contact formation and provide new insight into the signaling transactions elicited by this neurotransmitter in glial cells. J. Neurosci. Res. 66:723–729, 2001. © 2001 Wiley‐Liss, Inc.
Glutamate signalling and secretory phospholipase A2 modulate the release of arachidonic acid from neuronal membranes
Authors: Rodriguez de Turco Elena B. , Jackson Fannie R. , DeCoster Mark A. , Kolko Miriam , Bazan Nicolas G.
Published: August 2002

The lipid mediators generated by phospholipases A2 (PLA2), free arachidonic acid (AA), eicosanoids, and platelet‐activating factor, modulate neuronal activity; when overproduced, some of them become potent neurotoxins. We have shown, using primary cortical neuron cultures, that glutamate and secretory PLA2 (sPLA2) from bee venom (bv sPLA2) and Taipan snake venom (OS2) elicit synergy in inducing neuronal cell death. Low concentrations of sPLA2 are selective ligands of cell‐surface sPLA2 receptors. We investigated which neuronal arachidonoyl phospholipids are targeted by glutamate‐activated cytosolic calcium‐dependent PLA2 (cPLA2) and by sPLA2. Treatment of 3H‐AA‐labeled cortical neurons with mildly toxic concentrations of sPLA2 (25 ng/ml, 1.78 nM) for 45 min resulted in a two‐ to threefold higher loss of 3H‐AA from phosphatidylcholine (PC) than from phosphatidylethanolamine (PE) and in minor changes in other phospholipids. A similar profile, although of greater magnitude, was observed 20 hr posttreatment. Glutamate (80 μM) induced much less mobilization of 3H‐AA than did sPLA2 and resulted in a threefold greater degradation of 3H‐AA PE than of 3H‐AA PC by 20 hr posttreatment. Combining sPLA2 and glutamate resulted in a greater degradation of PC and PE, and the N‐methyl‐D‐aspartate receptor antagonist MK‐801 only blocked glutamate effects. Thus, activation of the arachidonate cascade induced by glutamate and sPLA2 under experimental conditions that lead to neuronal cell death involves the hydrolysis of different (perhaps partially overlapping) cellular phospholipid pools. © 2002 Wiley‐Liss, Inc.
Response of amoeboid microglia/brain macrophages in fetal rat brain exposed to a teratogen
Authors: Hao Ai‐Jun , Dheen S. Thameem , Ling Eng‐Ang
Published: August 2002

This study examined the time course response of amoeboid microglia/brain macrophages in the rat fetus induced by a single intraperitoneal injection of cyclophosphamide, a teratogen, into the mother rat at 13 days of gestation. Compared to the normal fetal brain, a marked increase in amoeboid microglia was observed in the telencephalon and diencephalon of experimental fetuses, especially in those killed at embryonic day 15. Conglomerations of microglia occurred in the dorsal and superior neuroepithelium of diencephalon, basal telencephalon, cortical neuroepithelium, and hippocampal formation as identified with OX‐42, OX‐18, and ED‐1 by immunohistochemistry. Rhodamine isothiocynate (RhIc) as a tracer was injected via the tail vein into the pregnant rat to assess the phagocytic capability of these cells. Following the tracer injection, none of microglial cells in normal fetal brain was detectable. RhIc, however, was readily taken up by amoeboid microglia in fetal brain with injury insult. Double labeling has shown that the RhIc‐labeled cells were immunoreactive with ED‐1, OX‐42, OX‐18, and OX‐6, confirming their microglial nature. Microglial proliferation was assessed by immunohistochemistry using bromodeoxyuridine, which showed a marked increase in mitotic activity. Confocal microscopic analysis revealed that a varying number of microglia coexpressed iNOS, macrophage colony‐stimulating factor (M‐CSF), and ICAM‐1. RT‐PCR analysis showed increased expression of M‐CSF mRNA. Furthermore, colony‐stimulating factor‐1 receptor mRNA was localized in microglia by in situ hybridization. The present results suggest that NO along with M‐CSF and ICAM‐1 is involved in microglial proliferation in prenatal brain injury. J. Neurosci. Res. 64:79–93, 2001. © 2001 Wiley‐Liss, Inc.
Tenascin‐Y is concentrated in adult nerve roots and has barrier properties in vitro
Authors: Tucker Richard P. , Hagios Carmen , Santiago Alicia , Chiquet‐Ehrismann Ruth
Published: August 2002

Several molecules have been identified as potential sources of the barriers to glial cell mixing and sensory regeneration that exist at the boundary between the peripheral and central nervous systems, including tenascin‐C, tenascin‐R, chondroitin sulfate proteoglycans, and NG2. Here we show that tenascin‐Y, the avian homologue of tenascin‐X, is concentrated in the proximal portions of peripheral nerves in the chicken. In vitro analyses of cultures enriched for Schwann cells demonstrate that recombinant tenascin‐Y has dose‐dependent effects on glial cell attachment, spreading, and migration. In addition, nanomolar concentrations of tenascin‐Y cause the rapid collapse of sensory growth cones cultured on fibronectin, and regenerating sensory neurites preferentially migrate on fibronectin and avoid tenascin‐Y in microstripe assays. We conclude that the expression pattern of tenascin‐Y and its properties in vitro are consistent with a role as an inhibitor of glial cell migration and sensory regeneration in nerve roots. J. Neurosci. Res. 66:439–447, 2001. © 2001 Wiley‐Liss, Inc.
Early formation of mature amyloid‐β protein deposits in a mutant APP transgenic model depends on levels of Aβ1–42
Authors: Rockenstein Edward , Mallory Margaret , Mante Michael , Sisk Abyanné , Masliaha Eliezer
Published: August 2002

The main objective of the present study was to develop an alternative singly‐transgenic (tg) hAPP model where amyloid deposition will occur at an earlier age. For this purpose, we generated lines of tg mice expressing hAPP751 cDNA containing the London (V717I) and Swedish (K670M/N671L) mutations under the regulatory control of the murine (m)Thy‐1 gene (mThy1‐hAPP751). In the brains of the highest (line 41) and intermediate (lines 16 and 11) expressers, high levels of hAPP expression were found in neurons in layers 4–5 of the neocortex, hippocampal CA1 and olfactory bulb. As early as 3–4 months of age, line 41 mice developed mature plaques in the frontal cortex, whereas at 5–7 months plaque formation extended to the hippocampus, thalamus and olfactory region. Ultrastructural and double‐immunolabeling analysis confirmed that most plaques were mature and contained dystrophic neurites immunoreactive with antibodies against APP, synaptophysin, neurofilament and tau. In addition, a decrease in the number of synaptophysin‐immunoreactive terminals was most prominent in the frontal cortex of mice from line 41. Mice from line 11 developed diffuse amyloid deposits at 11 months of age, whereas mice from line 16 did not show evidence of amyloid deposition. Analysis of Aβ by ELISA showed that levels of Aβ1–40 were higher in mice that did not show any amyloid deposits (line 16), whereas Aβ1–42 was the predominant species in tg animals from the lines showing plaque formation (lines 41 and 11). Taken together this study indicates that early onset plaque formation depends on levels of Aβ1–42. J. Neurosci. Res. 66:573–582, 2001. © 2001 Wiley‐Liss, Inc.
A statistical–topographic model using an omnidirectional parameterization of the relief for mapping orographic rainfall
Authors: Drogue G. , Humbert J. , Deraisme J. , Mahr N. , Freslon N.
Published: August 2002

The knowledge of rainfall patterns is a key issue for regionalization in hydroclimatic studies. In mountainous areas, the sparsity of the measurement network and the complexity of relationships between rainfall and topography make an accurate and reliable spatialization of rainfall amounts at the regional scale difficult. The purpose of this paper is to present an objective, analytical and automatic model of quantification and mapping of orographic rainfall applied to the north‐eastern part of France but also applicable in other complex terrain. PLUVIA distributes point measurements of monthly, annual and climatological rainfall to regularly spaced grid cells through a multiple regression analysis of rainfall versus morpho‐topographic parameters derived from a digital elevation model. The use of an omnidirectional parameterization of the topography induced by a windowing technique allows better account to be taken of the synoptic‐scale weather systems generating the different rainfall quantities of interest and the spatial scale of orographic effects. It also provides a more physical interpretation of geographical and topographical parameters selected for spatial estimation. The application relies on a network of more than 150 rain gauges spread over 30 000 km2 and concerns monthly to several yearly amounts of a sequence of 20 years. Advantages and limitations of the PLUVIA system are compared with those of two commonly used methods of multi‐variate geostatistics: kriging with external drift and extended collocated co‐kriging. Copyright © 2002 Royal Meteorological Society.
The anharmonic behavior of the oxygen modes in YBa2Cu3Ox compounds
Authors: Liarokapis E. , Palles D. , Conder K. , Kaldis E.
Published: August 2002

The anharmonic behavior of the Raman‐active oxygen modes was examined in YBa2Cu316,18Ox compounds over the whole range of oxygen doping (6 < x < 7). The apex phonon of Ag symmetry shows a small anharmonicity in the range of 6.4 < x < 6.9, which can be attributed to the anharmonic behavior of this mode in one of the constituent phases (ortho‐II, ortho‐III, etc.), but not in the ortho‐I phase. The B1g mode does not show any anharmonicity over the whole range of oxygen doping, but characteristic spectral changes appear for x ≈ 6.3 and 6.7. At the lowest oxygen content studied (x = 6.03), there is a considerable amount of anharmonicity for the in‐phase phonon of the plane oxygen atoms, which remains large until x ≈ 6.3, at the phase transition to the tetragonal phase, where it drops to zero. It increases again for x ≈ 6.4 and then gradually decreases with doping to disappear at the optimal doping. If these changes are combined with the spectral modifications of the B1g and in‐phase modes, they indicate that local structural changes are induced by the transfer of carriers to the CuO2 planes at x ≈ 6.3, which are related to the reduction in anharmonicity, the pinning of the carriers and superconductivity. Copyright © 2001 John Wiley & Sons, Ltd.
Vibrational analysis of NADH cofactors bound to glycerol‐3‐phosphate dehydrogenase and dogfish lactate dehydrogenase
Authors: van Beek Jeroen , Deng Hua , Callender Robert , Burgner John
Published: August 2002

The dehydrogenases catalyze the interconversions of aldehydes and alcohols in hydride transfer reactions to and from the re or si face of the nicotinamide ring of NAD with a high degree of stereospecificity. We report on the Raman spectra of NADH bound to dogfish lactate dehydrogenase (dfLDH), which transfers to and from the re face, and glycerol‐3‐phosphate dehydrogenase (G3PDH), which transfers to and from the si face. All theories of the mechanism of the stereospecificity must be in accord with the ground‐state native protein–cofactor structure, and the vibrational spectrum of the dihydronicotinamide ring of NADH is sensitive to apoprotein–cofactor interactions. Our results show that the amide NH2 rocking mode shifts up by about 30 cm−1 when NADH is bound in dfLDH while virtually unchanged in G3PDH. The upward shift of the rocking mode indicates a stronger hydrogen bonding on the NH2 moiety in dfLDH. Thus, the results are interpreted to show that the bound dihydronicotinamde head group interacts more strongly with surrounding protein and deforms to a greater extent in dfLDH than in G3PDH. It is concluded that a simple geometrical interpretation explaining the stereospecificity of hydride transfer in dehydrogenases is an adequate molecular description and that there is no need to invoke ‘activation’ of hydride transfer from one side of the NADH ring over the other. On the other hand, the results suggest that the fidelity of the stereospecificity for G3PDH should be much less than that found for LDH. Copyright © 2002 John Wiley & Sons, Ltd.
31P NMR analysis of chicken breast meat vacuum tumbled with NaCl and various phosphates
Authors: Li Rongrong , Kerr William L , Toledo Romeo T , Teng Quincy
Published: August 2002

The hydrolysis of several commercially used phosphates was studied in chicken breast meat marinated and tumbled in 70 g kg−1 NaCl and 12 g kg−1 of either disodium pyrophosphate (DSPP), tetrasodium pyrophosphate (TSPP), tetrapotassium pyrophosphate (TKPP), sodium tripolyphosphate (STPP) or glass phosphate. After treatment, intact muscle was ground in the presence of EDTA‐Na2 to prevent further enzymatic breakdown of phosphates. TSPP and TKPP were fully hydrolysed within 1.25 h, STPP within 3.25 h, DSPP within 6 h and glass phosphate within 24 h. DSPP lowered the muscle pH from 5.97 to 5.60, while TSPP and TKPP increased the pH to 6.10 and 6.19 respectively. Based on PP chemical shifts, the pH was found to increase with time. No evidence of tripolyphosphate (TPP) in the STPP‐treated samples was found, suggesting that it had already been hydrolysed to pyrophosphate (PP) or monophosphate (Pi) during treatment. PP hydrolysis occurred at about the same rate as Pi production in STPP‐treated samples. Pi production in meat treated with glass phosphate was relatively slow, indicating a lack of muscle enzymes capable of breaking down long‐chain phosphates. Late production of Pi after depletion of oligophosphate was attributed to hydrolysis of cellular phosphates.

© 2001 Society of Chemical Industry
Low levels of selenium in miscarriage
Authors: Güvenç Müzehher , Güven Hüseyin , Karataş Fikret , Aygün A. Denizmen , Bektaş Sırrı
Published: August 2002

Few data are presented in the literature about selenium and miscarriage. The aim of this article was to study the relationship between the selenium status of pregnant women and miscarriage. A randomized, controlled trial was performed in Elazig State Hospital and Firat University Hospital. Serum and hair samples were obtained from 20 non‐pregnant women, 32 healthy mothers with normal newborns, and 16 women who miscarried. Serum selenium levels, as ng/mL, and hair selenium levels, as ng/g, were determined on a Perkin–Elmer 1000 spectrophotometer by fluorometry. The mean serum and hair selenium concentrations of the women who miscarried (42.8 ± 2.7 ng/mL, 276 ± 6.6 ng/g, respectively) were significantly lower than those of the control healthy mothers (50.2 ± 2.3 ng/mL, 300 ± 6.1 ng/g, respectively) and the non‐pregnant women (58.1 ± 3.1 ng/mL, 315 ± 7.6 ng/g, respectively). Maternal selenium deficiency during early gestation was thought to be one of the factors responsible in the pathogenesis of miscarriage. More studies on maternal selenium status during pregnancy are needed. J. Trace Elem. Med. 15:97–101, 2002. © 2002 Wiley‐Liss, Inc.
State‐state transitions for CCl2(X1A1, A1B1, a3B1) radical and collisional quenching of CCl2(A1B1 and a3B1) by O2, N2, NO, N2O, NH3, and various aminated molecules
Authors: Gao Yide , Ran Qin , Chen Yang , Chen Congxiang
Published: August 2002

CCl2 free radicals were produced by a pulsed dc discharge of CCl4 in Ar. Ground electronic state CCl2(X) radicals were electronically excited to the A1B1 (0,4,0) vibronic state with an Nd:YAG laser pumped dye laser at 541.52 nm. Experimental quenching data of excited CCl2(A1B1 and a3B1) by O2, N2, NO, N2O, NH3, NH(CH3)2, NH(C2H5)2, and N(C2H5)3 molecules were obtained by observing the time‐resolved total fluorescence signal of the excited CCl2 radical in a cell, which showed a superposition of two exponential decay components under the presence of quencher. The quenching rate constants kA of CCl2(A) state and ka of CCl2(a) state were derived by analyzing the experimental data according to a proposed three‐level model to deal with the CCl2(X1A1, A1B1, a3B1) system. The formation cross sections of complexes of electronically excited CCl2 radicals with O2, N2, NO, N2O, NH3, and aminated molecules were calculated by means of a collision‐complex model. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 351–356, 2002
Physical soil degradation induced by deforestation and slope modification in a temperate‐humid environment
Authors: Varela M.E. , De Blas E. , Benito E.
Published: August 2002

Between February 1998 and March 1999 physical soil degradation was studied in temperate‐humid NW Spain after deforestation and slope modification. Changes in bulk density, total porosity, pore size distribution, aggregate stability and soil mechanical strength indicated the degradation process. Slope levelling produced the greatest impact. A rapid recovery of physical properties was observed, with the exception of those related to the soil mechanical strength. The increased soil erosion needs agronomic studies to understand the long‐term benefits and adverse aspects of the land‐use changes. Copyright © 2001 John Wiley & Sons, Ltd.
Skin protection for photosensitized patients
Authors: Schwarz Viola A. , Klein Sabine D. , Hornung René , Knochenmuss Richard , Wyss Pius , Fink Daniel , Haller Urs , Walt Heinrich
Published: August 2002

Background and Objective

The goal of this study was to evaluate various creams for their capability to protect photosensitized skin from visible light.

Study Design/Materials and Methods

Two cover creams and creams containing various combinations of Vaseline with TiO2, ZnO, and Fe2O3 were used to measure the reduced light transmission and the light absorption spectrum. In vitro and in vivo tests were performed to assess the protection from light by above mentioned compounds.

Results

The cover creams and the 50% TiO2 cream showed similar efficacy in reducing light transmission, while the sunscreen was less efficient by a factor of 5. Cell protection by 25% TiO2+25% ZnO, TiO2, or the cover creams was more efficient than protection by the sunscreen or other compounds. In vivo, the dark cover cream protected the skin by a factor of 3.4 better than the sunscreen.

Conclusions

The dark cover cream has acceptable properties to protect photosensitized skin. Lasers Surg. Med. 29:252–259, 2001. © 2001 Wiley‐Liss, Inc.
Promoter CpG methylation of Hox‐a10 and Hox‐a11 in mouse uterus not altered upon neonatal diethylstilbestrol exposure*
Authors: Li Shuanfang , Ma Liang , Chiang Tung‐chin , Burow Matthew , Newbold Retha R. , Negishi Masahiko , Barrett J. Carl , Mclachlan John A.
Published: August 2002

Mouse abdominal B–like Hoxa genes are expressed and functionally required in the developing reproductive tracts. Mice lacking either Hoxa‐10 or Hoxa‐11, two of the AbdB Hoxa genes, exhibit abnormal uterine development similar to that induced by in utero diethylstilbestrol (DES) exposure. Indeed, uterine Hoxa‐10 and Hoxa‐11 expression is potently repressed by perinatal DES exposure, providing a potential molecular mechanism for DES‐induced reproductive tract malformations. We have shown previously that DES can permanently alter uterine lactoferrin gene expression through modulation of the lactoferrin promoter methylation pattern. Here we ask whether a similar mechanism also functions to deregulate uterine Hoxa‐10 or Hoxa‐11 expression during neonatal DES exposure. We mapped the Hoxa‐10 promoter by cloning a 1.485 kb DNA fragment 5′ of the Hoxa‐10 exon1a. A 5′ rapid amplification of cDNA ends (RACE) experiment revealed a transcription start site for the a10‐1 transcript. Functional analysis of the proximal 200‐bp sequences demonstrated significant promoter activity, confirming the location of the Hoxa‐10 promoter. Moreover, methylation assays performed on eight CpGs in Hoxa‐10 and 19 CpGs in Hoxa‐11 proximal promoters demonstrated that all these CpGs were highly unmethylated in both control and DES‐dosed mice from postnatal day 5 to day 30. Significant methylation around Hoxa‐10 and Hoxa‐11 promoters was only observed in DES‐induced uterine carcinomas in 18‐mo‐old mice. Our results suggest that DES‐induced downregulations of Hoxa‐10 or Hoxa‐11 gene expression are not associated with methylation changes in their proximal promoters and that gene imprinting by developmental DES exposure may be a gene‐specific phenomenon. Published 2001 Wiley‐Liss, Inc.
Loss of mismatch repair activity in simian virus 40 large T antigen–immortalized BPH‐1 human prostatic epithelial cell line
Authors: Yeh Che‐Chung , Lee Celeste , Huang Mei‐Chuan , Dahiya Rajvir
Published: August 2002

Simian virus 40 large T antigen (SVLTAg) has been used to immortalize cells; however, the mechanism leading to immortalization is still unclear. We hypothesize that DNA mismatch repair (MMR) activity is important during SVLTAg‐induced immortalization. To test this hypothesis, we used the SVLTAg‐immortalized cell line BPH‐1 derived from human benign prostate epithelial cells to analyze MMR activity and the expression of MMR genes (hMLH1, hPMS1, hPMS2, hMSH2, hMSH3, and hMSH6). The results demonstrated that BPH‐1 cells were deficient in repairing G:T, A:C, and G:G mispairs in bacteriophage M13mp2. Reverse‐transcription polymerase chain reaction experiments indicated MMR genes (hMSH3, hMSH6, and hPMS1) were expressed at a low level in BPH‐1 cells. In contrast, all six MMR genes were expressed in human benign prostate hyperplasia tissues. Downregulation of hMSH3, hMSH6, and hPMS1 genes is not a result of the hypermethylation mechanism because demethylation with 5‐aza‐2′‐deoxycytidine did not restore expression of these genes. Although the hMLH1 gene is expressed in BPH‐1 cells, western blotting and exon analyses demonstrated that hMLH1 was mutated and/or deleted in BPH‐1 cells. © 2001 Wiley‐Liss, Inc.
Tremor associated with benign IgM paraproteinaemic neuropathy successfully treated with gabapentin
Authors: Saverino A. , Solaro C. , Capello E. , Trompetto C. , Abbruzzese G. , Schenone A.
Published: August 2002

We describe a 76‐year‐old patient with a severe tremor due to chronic demyelinating neuropathy associated with a benign IgM paraproteinaemia that was successfully treated with gabapentin. The patient reached the full dose of 1,200 mg/day of gabapentin without side effects and showed a significant therapy‐related improvement of tremor and disability, as judged by the Fahn Tolosa Marin Rating Scale. © 2001 Movement Disorder Society.
The chorea of McLeod syndrome
Authors: Danek A. , Tison F. , Rubio J. , Oechsner M. , Kalckreuth W. , Monaco A.P.
Published: August 2002

Among the movement disorders associated with acanthocytosis, McLeod syndrome (McKusick 314850) is the one that is best characterized on the molecular level. Its defining feature is low reactivity of Kell erythrocyte antigens. This is due to absence of membrane protein KX that forms a complex with the Kell protein. KX is coded for by the XK gene on the X‐chromosome. We present six males (aged 29 to 60 years), with proven XK mutations, to discuss the chorea associated with McLeod syndrome. The movement disorder commonly develops in the fifth decade and is progressive. It affects the limbs, the trunk and the face.

In addition to facial grimacing, involuntary vocalization can be present. In early stages there may only be some restlessness or slight involuntary distal movements of ankles and fingers. Lip‐biting and facial tics seem more common in autosomal recessive choreoacanthocytosis linked to chromosome 9. This, together with the absence of dysphagia in McLeod syndrome, may help in differential diagnosis. Recent findings suggest a role for the endothelin system of the striatum in the pathogenesis of McLeod syndrome. © 2001 Movement Disorder Society.
Gracilis muscle neosphincter for treating urinary incontinence
Authors: Perez‐Abadia Gustavo , Van Aalst Vera C. , Palacio Martin M. , Werker Paul M.N. , Ren Xiaopin , Van Savage John , Fernandez Angel Garcia , Kon Moshe , Barker John H.
Published: August 2002

The purpose of this study was to test the anatomical and functional feasibility of using a gracilis muscle free flap to create a urinary sphincter. Anatomical studies were performed in 12 human cadavers and short‐term (n = 7) and long‐term (n = 8) functional studies were performed in dogs. In the short‐term functional studies, the left gracilis muscle was transferred into the pelvis and wrapped around the urethra and the right gracilis muscle was wrapped around a stent. A cuff electrode was placed on the muscle's nerve pedicle and used to stimulate the neosphincter while peak pressure, fatigue rate, and perfusion measurements were performed. In the long‐term functional studies, intramuscular electrodes were inserted into the neosphincter to stimulate the flap. The flaps were wrapped around the urethra and dogs were followed for 16 weeks, during which time urodynamic measurements were performed. Our anatomical studies demonstrated that the gracilis muscle free flap could be transferred into the pelvis to create a urinary neosphincter. Our short‐term functional study demonstrated that gracilis muscle free‐flap function and perfusion were not compromised by transfer. In our long‐term functional study, all neosphincters provided bladder outlet resistance pressures consistent with continence. Our anatomical, short‐term, and long‐term functional studies indicate that a gracilis muscle free‐flap neosphincter is an effective procedure for treating urinary incontinence. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:271‐280 2001
A regularization procedure for the auto‐correlation equation
Authors: Von Wolfersdorf L.
Published: August 2002

The paper deals with the auto‐correlation equation and its regularization by means of a Lavrent'ev regularization procedure in L2. The solution of this quadratic integral equation of the first kind and of the regularized equation of the second kind are obtained by reduction to a boundary value problem for the Fourier transform of the solution. We prove convergence of the approximate solution to the exact solution and derive a stability estimate for the error. Copyright © John Wiley & Sons, Ltd.
Design of broadband microwave amplifier using lumped and distributed impedance transformers
Authors: Kim Nam‐Tae
Published: August 2002

The design of impedance‐matching networks, which use lumped and distributed impedance transformers, is presented to achieve the broadband performance of microwave amplifiers. Matching circuits of an amplifier are constructed by cascading lumped and distributed impedance transformers that exhibit Chebyshev transfer characteristics. Element values and impedance transformation ratios for specified transformer structures are calculated and tabulated in terms of their insertion losses and ripples. To validate the performance of matching networks using lumped and distributed impedance transformers, the results are applied to the design of an octave‐band microwave transistor amplifier. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 405–408, 2001.
High‐performance L‐band series and parallel switches using low‐cost p‐i‐n diodes
Authors: Karmakar Nemai C. , Bialkowski Marek E.
Published: August 2002

Low‐cost UHF‐band p‐i‐n diodes are used to develop high‐performance L‐band series and parallel switches. To stop the rectification of large RF signals, the diodes are biased at a large reverse‐bias voltage. Parasitic elements of the diodes are tuned out using LC circuits in biasing circuits without increasing the size of the switches. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 367–370, 2002.
Carbon isotopomers of tetrafluoroethylene: laser‐induced synthesis and NMR spectroscopic characterization
Authors: Kühn‐Velten J. H. , Hägele G. , Fuss W. , Hering P. , Ivanenko M. M.
Published: August 2002

Isotopically selective multiphoton dissociation of CHClF2 produced a mixture of 12C/13C isotopomeric tetrafluoroethylenes. Specific NMR parameters for each isotopomer and the composition of this mixture were obtained from 13C and 19F NMR spectra by spectral analysis using consecutively lineshape and peak top iteration methods. Copyright © 2001 John Wiley & Sons, Ltd.
Comparison of glycoprotein hormone α‐subunits of laboratory animals
Authors: Suzuki Osamu , Mochida Keiji , Yamamoto Yoshie , Noguchi Yoko , Takano Kaoru , Matsuda Junichiro , Ogura Astuo
Published: August 2002

The common α‐subunit of glycoprotein hormones (CGα) is a core protein shared by follicle‐stimulating hormone (FSH), luteinizing hormone (LH), and thyroid‐stimulating hormone (TSH). In order to obtain a molecular basis for an efficient superovulation technique applicable to a wide range of animal species and to discuss the phylogenetic aspect based on molecules related to the reproductive system, we determined cDNA sequences of CGα in seven laboratory animals: the guinea pig, Mongolian gerbil, golden hamster, mastomys, Japanese field vole, the JF1 strain of Mus musculus molossinus, and rabbit. Comparison of the inferred CGα amino acid sequences of these animals and other mammals (human, mouse, rat, cow, pig, and sheep) showed that the signal peptides and the first ten residues at the N‐terminus of the apoprotein were variable, while the rest of the apoproteins were highly conserved. In particular, all rodents had a leucine residue at the apoprotein N‐terminus, except the guinea pig, which had a phenylalanine residue, as in the cow, pig, sheep, and rabbit. Phylogenetic trees constructed from amino acid sequences suggest a closer relationship between the guinea pig and artiodactyls than to rodents, confirming the taxonomic peculiarity of the guinea pig. Mol. Reprod. Dev. 62: 335–342, 2002. © 2002 Wiley‐Liss, Inc.
Evolution of octopod sperm I: Comparison of nuclear morphogenesis in Eledone and Octopus
Authors: Gimenez‐Bonafé Pepita , Ribes Enric , Zamora Maria J. , Kasinsky Harold E. , Chiva Manel
Published: August 2002

Morphogenesis of the Eledone cirrhosa sperm nucleus, as studied by electron microscopic techniques, is compared with that of Octopus vulgaris. Both species of cephalopods belong to the family Octopodidae. The results indicate that extensive nuclear helicoidization during E. cirrhosa spermiogenesis is brought about by modifications of the function of structural components already present in the late steps of O. vulgaris spermiogenesis. In particular, changes in the regulation of perinuclear microtubule contraction in E. cirrhosa spermatids, as well as a decrease in basicity of protamines, promote nuclear helicoidization. Disulphide bond formation between protamine molecules fixes the completely helicoidal shape of the nucleus in mature sperm of E. cirrhosa. Mol. Reprod. Dev. 62: 357–362, 2002. © 2002 Wiley‐Liss, Inc.
Supporting communication in young children with developmental disabilities
Authors: Kaiser Ann P. , Hester Peggy P. , McDuffie Andrea S.
Published: August 2002

The behavior of parents, adult caregivers, and peers comprises the critical features of community support for the development of communication in young children with developmental disabilities. In a bio‐ecological model of development, communication development is the result of the interactions of individuals with specific characteristics, in particular contexts over time. From the perspective of this model, foundational findings of intervention research to current views of communication development in children with developmental disabilities are summarized. The contributions of individual child characteristics to child–caregiver interactions that support language development are illustrated based on research with children who have autism, Williams syndrome, Down syndrome, and children who use augmentative communication systems. Parent–child interaction and the quality and quantity of parent talk are discussed as factors in children's language development. The effects of young children's delayed language on their interactions with peers, the contributions of peers to children's language learning and use, and the critical features of classroom settings that support child language development are reviewed. MRDD Research Reviews 7:143–150, 2001. © 2001 Wiley‐Liss, Inc.
Reducing oblique flow effects in interleaved EPI with a centric reordering technique
Authors: Beck Gabriele , Li Debiao , Haacke E. Mark , Noll Tobias G. , Schad Lothar R.
Published: August 2002

Segmented interleaved echo planar imaging offers a fast and efficient approach to magnetic resonance angiography. Unfortunately, this technique is particularly sensitive to oblique flow in the imaging plane. In this work, a mathematical analysis of oblique flow effects for several types of k‐space coverage is presented. The conventional linear acquisition scheme, an alternating centric and a nonalternating centric encoding scheme are compared with respect to their flow properties. It is shown both by simulations and imaging experiments that artifacts from oblique in‐plane flow are effectively reduced by both centric reordered phase‐encoding schemes. The nonalternating centric acquisition scheme is preferred to the alternating centric scheme due to the smoother phase error transition in k‐space in the presence of obliquely‐angled flow. Magn Reson Med 45:623–629, 2001. © 2001 Wiley‐Liss, Inc.
Perfusion imaging using spin‐labeling methods: Contrast‐ to‐noise comparison in functional MRI applications
Authors: Preibisch Christine , Haase Axel
Published: August 2002

In this study the performance of FLASH imaging with selective inversion preparation for functional perfusion studies was investigated. In addition to the absolute quantification of perfusion by measurement of the longitudinal relaxation times with global (T1glob) and selective (T1sel) inversion, the measurement of absolute (BASE) and relative (FAIR) perfusion increases by subtraction of appropriately weighted images was also considered. The subject averages of absolute perfusion obtained by the quantitative method were 70.7 ± 4.0 ml/100g/min in gray matter, 10.2 ± 3.4 ml/100g/min in white matter, and 89.0 ± 3.1 ml/100g/min in visual cortex. These values, as well as the average increase of perfusion due to visual stimulation (44.4 ± 3.7 ml/100g/min), agree well with respective data reported by PET and other MRI studies. However, for individual subjects the standard deviations over single ROIs inside the visual cortex lay around 100% which prevented the detection of significant activation. BASE and FAIR, on the other hand, were able to detect significant activation in single subjects. The measured average perfusion increases were 51.7 ± 6.6 ml/100g/min and 56.5 ± 13.8%, respectively. Magn Reson Med 46:172–182, 2001. © 2001 Wiley‐Liss, Inc.
Single‐shot EPI with signal recovery from the susceptibility‐induced losses
Authors: Song Allen W.
Published: August 2002

A major problem in the gradient‐recalled echo‐planar imaging (EPI) method that also uses a long echo time (TE) is the severe signal loss in regions with large static field inhomogeneities. These regions include the ventral frontal, medial temporal, and inferior temporal lobes, which experience inhomogeneities induced by susceptibility effects commonly found near air/tissue interfaces. For functional magnetic resonance imaging (fMRI) studies that use both gradient‐recalled EPI at relatively long TE and high‐field scanners, this signal loss is severe, preventing investigation of certain human cognitive processes that involve these regions, such as memory and attention. Methods have been developed to recover this signal loss; however, most of them require multiple excitations and thus compromise temporal resolution. In this report, a new technique is described which achieves good signal recovery within a single excitation. It is anticipated that this technique will prove useful for fMRI studies in inhomogeneous areas that require high temporal resolution. Magn Reson Med 46:407–411, 2001. © 2001 Wiley‐Liss, Inc.
Novel cooling channel shapes in pressure die casting
Authors: Clark L. D. , Davey K. , Hinduja S.
Published: August 2002

The pressure die casting involves die designs incorporating cooling channels positioned to facilitate the controlled extraction of energy from a solidifying casting. It is now known that subcooled nucleate boiling can occur in cooling channels and this paper is concerned with novel cooling channel shapes that are optimized to promote and enhance this boiling and thus reduce casting times. Shape sensitivity analysis is applied to a boundary element model using the material derivative adjoint variable technique. Mesh node positions on the cooling channels are used as the design parameters. The sensitivities are used in a conjugate gradient non‐linear optimization routine. It is shown that with this approach cooling channels can be designed to maximize boiling heat transfer whilst at the same time allow some degree of control of spatial temperature variation over the die cavity surface. Simulation and experimental results are presented for a traditional die and an optimized die. A 60 per cent reduction in cycle time is achieved with the optimized die. Copyright © 2001 John Wiley & Sons, Ltd.