bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulin‐like growth factors (IGF‐I and IGF‐II) inhibit C2 skeletal myoblast differentiation and enhance TNFα‐induced apoptosis
Authors: Foulstone Emily J. , Meadows Kate A. , Holly Jeff M.P. , Stewart Claire E.H.
Published: August 2002

IGF‐I and IGF‐II are thought to be unique in their ability to promote muscle cell differentiation. Murine C2 myoblasts differentiate when placed into low serum media (LSM), accompanied by increased IGF‐II and IGF binding protein‐5 (IGFBP‐5) production. Addition of 20 ng/ml TNFα on transfer into LSM blocked differentiation, IGF‐II and IGFBP‐5 secretion and induced apoptosis. We, therefore, wished to assess whether IGFs could protect against the effects of TNFα. Neither inhibition of differentiation or induction of apoptosis was rescued by co‐incubation with IGF‐I or IGF‐II. A lower dose of TNFα (1 ng/ml) while not inducing apoptosis still inhibited myoblast differentiation by 56% ± 12, (P < 0.001), indicating that induction of apoptosis is not the sole mechanism by which TNFα inhibits myoblast differentiation. Addition of IGF‐I or IGF‐II alone reduced differentiation by 49% ± 15 and 33% ± 20, respectively, (P < 0.001), although neither induced apoptosis. For muscle cells to differentiate, they must arrest in G0. We established that addition of IGF‐I, IGF‐II or TNFα to the myoblasts promoted proliferation. The myoblasts could not exit the cell cycle as efficiently as controls and differentiation was thus reduced. Unexpectedly, co‐incubation of IGF‐I or IGF‐II with 1 ng/ml TNFα enhanced the inhibition of differentiation and induced apoptosis. In the absence of apoptosis we show an association between IGF‐induced inhibition of differentiation and increased IGFBP‐5 secretion. These results indicate that the effects of the IGFs on muscle may depend on the cytokine environment. In the absence of TNFα, the IGFs delay differentiation and promote myoblast proliferation whereas in the presence of TNFα the IGFs induce apoptosis. © 2001 Wiley‐Liss, Inc.
Detection and localization of Cripto‐1 binding in mouse mammary epithelial cells and in the mouse mammary gland using an immunoglobulin–cripto‐1 fusion protein†
Authors: Bianco Caterina , Normanno Nicola , De Luca Antonella , Maiello Monica Rosaria , Wechselberger Christian , Sun Youping , Khan Nadia , Adkins Heather , Sanicola Michele , Vonderhaar Barbara , Cohen Bruce , Seno Masaharu , Salomon David
Published: August 2002

Human Cripto‐1 (CR‐1), a member of the epidermal growth factor‐CFC (EGF‐CFC) family of peptides, is expressed in the developing mouse mammary gland and can modulate mammary epithelial cell migration, branching morphogenesis and milk protein expression in vitro. In order to screen for a CR‐1 receptor and to identify potential CR‐1 target tissues, we constructed a fusion protein comprising the EGF‐like domain of CR‐1 and the Fc domain of a human IgG1. The recombinant CR‐1 fusion protein (CR‐1‐Fc) was biologically active as it was able to activate the ras/raf/mitogen activated protein kinase (MAPK) pathway and to inhibit transcription of the milk protein β‐casein in NMuMG and HC‐11 mouse mammary epithelial cells. By using immunocytochemistry and by an in situ enzyme‐linked immunosorbent assay (ELISA), CR‐1‐Fc was found to specifically bind to NMuMG and HC‐11 cells. Finally, immunohistochemical analysis using CR‐1‐Fc showed a specific localization of CR‐1 binding to tissue sections from mouse mammary gland. In particular, more than 60% of the epithelial cells were intensely stained with the CR‐1‐Fc fusion protein in the lactating mouse mammary gland, whereas approximately 25% of the mammary epithelial cells were stained in the gland from pregnant mouse. Since expression of mouse cripto‐1 (Cr‐1) in the pregnant and lactating mouse mammary gland as well as its presence in milk has been previously demonstrated, these data strongly suggest that an autocrine pathway involving Cr‐1 and its putative receptor is operating in the mouse mammary gland during pregnancy and lactation. J. Cell. Physiol. 190: 74–82, 2002. Published 2002 Wiley‐Liss, Inc.
Na+/K+/Cl− cotransporter activates mitogen‐activated protein kinase in fibroblasts and lymphocytes
Authors: Panet Rivka , Eliash Michal , Pick Marjory , Atlan Henri
Published: August 2002

In a previous work, we have shown that overexpression of the Na+/K+/Cl− cotransporter (NKCC1) induces cell proliferation and transformation. We investigate in the present study the role of the NKCC1 in the mitogenic signal transduction. We show that overexpression of the cotransporter gene (NKCC1) in stablely transfected cells (Balb/c‐NKCC1), resulted in enhanced phosphorylation of the extracellular regulated kinase (ERK) to produce double phosphorylated ERK (DP‐ERK). Furthermore, the level of DP‐ERK was reduced by 50–80% following the addition of bumetanide, a specific inhibitor of the Na+/K+/Cl− cotransporter, in quiescent as well as in proliferating cultures of the Balb/c‐NKCC1 clone. In order to explore further the role of the Na+/K+/Cl− cotransporter in mitogenic signal transduction, we measured the effect of the two specific inhibitors of the cotransporter; bumetanide and furosemide, on DP‐ERK level in immortalized non‐transformed cells. In Balb/c 3T3 fibroblasts stimulated with FGF, bumetanide, and furosemide inhibited 50–60% of the ERK 1/2 phosphorylation. The inhibitor concentration needed for maximal inhibition of ERK 1/2 phosphorylation was similar to the concentration needed to block the K+ influx mediated by the Na+/K+/Cl− cotransporter in these cells. To analyze whether the Na+/K+/Cl− cotransporter has a role in the mitogenic signal of normal cells, we measured the effect of bumetanide on ERK phosphorylation in human peripheral blood lymphocytes. The phosphorylation of ERK 1/2 in resting human lymphocytes, as well as in lymphocytes stimulated with phytohemagglutinin (PHA) was inhibited by bumetanide. The effect of bumetanide on ERK 2 phosphorylation was much lower than that of ERK 1 phosphorylation. The finding that the Na+/K+/Cl− cotransporter controls the ERK/MAPK (mitogen‐activated protein kinase) signal transduction pathway, support our hypothesis that Na+ and K+ influxes mediated by this transporter plays a central role in the control of normal cell proliferation. Exploring the cellular ionic currents and levels, mediated by the Na+/K+/Cl− cotransporter, should lead to a better comprehension of cell proliferation and transformation machinery. J. Cell. Physiol. 190: 227–237, 2002. © 2002 Wiley‐Liss, Inc.
Termination of lifespan of SV40‐transformed human fibroblasts in crisis is due to apoptosis
Authors: Macera‐Bloch Lisa , Houghton JeanMarie , Lenahan Melanie , Jha Krishna K. , Ozer Harvey L.
Published: August 2002

Normal human fibroblasts in culture have a limited lifespan, ending in replicative senescence. Introduction of SV40 sequences encoding large T antigen and small t antigen into pre‐senescent cells results in an extension of lifespan for an additional 20–30 population doublings. Rare clones of SV40‐transformed cells are capable of indefinite growth and are described as immortal; however, the great majority of SV40‐transformed cells terminate this extended lifespan in cell death, termed “crisis.” We have examined the properties of cells in crisis to obtain further insights into mechanism of cell death and immortalization. Populations at the terminal cell passage show a balance between cell replication and cell death over a period of several weeks, with a progressive increase in cells undergoing cell death. During this period, there is less than a 3‐fold increase in attached cell number, with two stages being identifiable on the basis of the focal pattern of cell survival. We also demonstrate that cells in crisis are undergoing apoptosis based on TUNEL assay, subG1 DNA content, annexin V reactivity, and activation of caspases 3 and 8. We suggest a model whereby SV40‐transformed cells acquire increased sensitivity to apoptosis based on changes in properties which activate caspase 8 in addition to changes previously described involving shortening of telomeric sequences. While only telomere stabilization could be clearly shown to be essential for survival of cells through crisis, the extended period of cell replication and altered gene expression observed in SV40‐transformed cells during crisis are compatible with other genetic alterations in immortal cells. J. Cell. Physiol. 190: 332–344, 2002. © 2002 Wiley‐Liss, Inc.
Simultaneous SOx /NOx removal in a fluidized bed reactor using natural manganese ore
Authors: Jeong Soon Kwan , Park Tae Sung , Hong Sung Chang
Published: August 2002

In this experiment, the simultaneous removal of SO2 and NO from flue gases was investigated through the use of natural manganese ore as a sorbent‐catalyst in a fluidized bed reactor. Selective catalytic reduction behavior was determined as a function of the sulfation degree within the temperature range from 100 °C to 500 °C. The natural manganese ore showed a high activity in the production of nitrogen and water by the reaction of nitric oxide with ammonia and oxygen up to around 200 °C. At higher temperatures, the nitric oxide removal efficiency decreased due to the oxidation of ammonia by oxygen. With the increase of sulfation degree, the temperature at which the maximum selective catalytic reduction of nitric oxide appears gradually increased, however the maximum nitric oxide removal efficiency decreased. Additionally, we investigated the removal efficiency of sulfur dioxide and nitric oxide with reaction time in a batch fluidized bed reactor within a temperature range of 350 °C to 500 °C. As the reaction temperature increased, the adsorption capacity of sulfur dioxide increased, but the nitric oxide removal efficiency decreased.

© 2001 Society of Chemical Industry
Transport of mercury(II) ion through a supported liquid membrane containing a triisobutylphosphine sulfide (Cyanex 471X) as a mobile carrier
Authors: Bhandare A A , Argekar A P
Published: August 2002

Carrier‐facilitated transport of mercury(II) against its concentration gradient from aqueous 0.1 mol dm−3 hydrochloric acid solution across a flat‐sheet supported liquid membrane (SLM) containing triisobutylphosphine sulfide (Cyanex 471X) as the mobile carrier in kerosene as diluent has been investigated. Dilute sodium thiocyanate solution (0.11 mol dm−3) was the most efficient stripping agent among several aqueous reagents tested. Various parameters such as stirring rate, concentration of HCl in the feed solution, concentration of NaSCN in the strippant, concentration of Cyanex 471X in the membrane, and contact time were investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is about 100% after 6 h. The carrier, Cyanex 471X, selectively and efficiently transported Hg(II) ions in the presence of other associated metal ions. The method has been demonstrated to recover selectively mercury from waste samples and mercurochrome solution.

© 2002 Society of Chemical Industry
Groin hernias in adults: Value of color doppler sonography in their classification
Authors: Zhang Guo‐Quan , Sugiyama Masanori , Hagi Hiroo , Urata Tsuyoshi , Shimamori Naoko , Atomi Yutaka
Published: August 2002

Purpose

We assessed the abilities of color Doppler and power Doppler sonography to distinguish among types of groin hernias by demonstrating the inferior epigastric artery (IEA) and its relationship with the hernia sac.

Methods

Nineteen consecutive patients (14 men and 5 women), clinically diagnosed as having groin hernias and scheduled to undergo herniorrhaphy, were prospectively enrolled in this study. Ultrasound examinations were performed preoperatively with a 6–12‐MHz linear‐array transducer. The IEA was identified, if possible, and its relationship to the hernia sac assessed. The sonographic diagnoses were compared with the operative findings.

Results

There were 15 indirect inguinal hernias, 4 direct inguinal hernias, and 1 femoral hernia; 1 patient had bilateral inguinal hernias (indirect and direct). In 18 (90%) of 20 hernia cases, the trunk segment of the IEA could be visualized. In 11 (55%) of 20 hernia cases, the origin segment of the IEA could be visualized and its relationship with the hernia sac assessed. In 9 (82%) of the 11 hernia cases, hernia types were correctly diagnosed by sonography. The overall accuracy of sonography for diagnosing the type of hernia was 45% (9 of 20 hernias).

Conclusions

Color Doppler sonography can accurately differentiate types of groin hernias if the origin segment of the IEA and the hernia sac can be visualized simultaneously. However, color Doppler sonography sometimes failed to visualize this segment. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29: 429–434, 2001.
Hydatid cyst of the liver presenting as an inferior vena cava obstruction
Authors: Rajagopal K.V. , Bishwas Rakesh
Published: August 2002

A 48‐year‐old woman presented with clinical features suggestive of an obstruction of the inferior vena cava (IVC). Abdominal sonography showed a 15‐ × 14‐cm cystic mass involving the medial segment of the left hepatic lobe and the anterior segment of the right hepatic lobe. We visualized multiple intracystic floating membranes, a detached endocyst, and a daughter cyst within the main cyst. The cyst was compressing and effacing the intrahepatic portion of the IVC and the right atrium. Sonography of the right and left hepatic veins showed blood flow in the normal direction, but spectral analysis showed that the flow was continuous, possibly owing to extrinsic compression of the IVC at the site where the hepatic veins drained into the IVC. The patient responded well to percutaneous treatment of the hydatid cyst. This case represents a rare presentation of a hydatid cyst of the liver. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:114–116, 2002. DOI 10.1002/jcu.10036
Obstructive jaundice caused by hepatocellular carcinoma: Detection by endoscopic sonography
Authors: Lee Yi‐Chia , Wang Hsiu‐Po , Huang Shih‐Pei , Chang Yu‐Ting , Wu Chen‐Tu , Yang Chang‐Shyue , Wu Ming‐Shiang , Lin Jaw‐Town
Published: August 2002

Tumor thrombus in the extrahepatic biliary tree is a rare mechanism of obstructive jaundice. We present a patient with a minute hepatocellular carcinoma in the caudate lobe that invaded the common hepatic duct and caused biliary obstruction. Endoscopic sonography showed a tumor thrombus with central echogenicity and a “nodule‐in‐nodule” pattern and suggested the correct diagnosis. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29:363–366, 2001.
A review of the epidemiological evidence on health effects of nitrogen dioxide exposure from gas stoves
Authors: Basu R. , Samet J.M.
Published: August 2002

This review addresses the evidence on the health effects of exposure to emissions of NO2 from gas stoves, covering findings of 45 epidemiological studies. These studies had addressed diverse outcome measures, including the risks of acute respiratory illness, decreased pulmonary function, respiratory symptoms and asthma exacerbation. Although most studies have focused on schoolchildren, studies of adults and more recently, prospective studies of infants have also been carried out. The findings have not been consistent across all studies in showing adverse effects. We conclude that the evidence does not support a causal relationship between exposure NO2 or use of a gas stove and increased risk for respiratory morbidity at the levels of NO2 typically associated with gas stoves. Some studies do show increased risk for respiratory health effects, however, and the evidence does not support the conclusion that NO2 emitted by gas stoves is risk‐free. Further research would be indicated if populations receiving exposures in a range of interest can be identified. Copyright © 1999 John Wiley & Sons, Ltd.

This review addresses the evidence on the health effects of exposure to emissions of NO2 from gas stoves, covering findings of 45 epidemiological studies. These studies had addressed diverse outcome measures, including the risks of acute respiratory illness, decreased pulmonary function, respiratory symptoms and asthma exacerbation. Although most studies have focused on schoolchildren, studies of adults and more recently, prospective studies of infants have also been carried out. The findings have not been consistent across all studies in showing adverse effects. We conclude that the evidence does not support a causal relationship between exposure NO2 or use of a gas stove and increased risk for respiratory morbidity at the levels of NO2 typically associated with gas stoves. Some studies do show increased risk for respiratory health effects, however, and the evidence does not support the conclusion that NO2 emitted by gas stoves is risk‐free. Further research would be indicated if populations receiving exposures in a range of interest can be identified. Copyright © 1999 John Wiley & Sons, Ltd.
The use and misuse of surrogate variables in environmental epidemiology
Authors: Lipfert Frederick W.
Published: August 2002

This paper discusses some common statistical problems that are often encountered in the specification and interpretation of regression models used in environmental epidemiology; such models have been used to establish new or modified ambient standards intended to protect public health. These statistical problems include: collinearity (identifying the ‘correct’ pollutant), confounding (omission of other variables that may be correlated with both response and putative dose), the ‘ecological fallacy’ (aggregating individual doses and responses over space or time), measurement error (uncertainties in data, applicability and measurement per se) and linearity (identifying curvature or thresholds in dose‐response function). These problems occur in both time‐series and cross‐sectional studies. Although none of these potential problem areas is new, they have rarely been considered together or comprehensively. This paper considers them as specific instances of the general problem of surrogate variables, for which an analytical framework is presented together with some examples of their practical consequences and some guidelines for interpreting environmental epidemiology studies. Findings of the analysis include: single‐pollutant regression models are likely to overstate effects; although aggregation results in loss of information, it biases the estimates only when confounding is present; the traditional approaches to correcting for measurement errors implied by the difference between personal exposures and ambient air quality do not apply, but estimates may be based on consideration of the ‘error’ term as an additional source of exposure; it may not be possible to deduce the correct shape of a dose‐response function in the presence of measurement error and correlated covariates. These findings are intended to be descriptive rather than definitive; the main purpose is to stimulate the detailed research required to develop practical remedies that would allow epidemiology to be used appropriately in setting environmental standards.Copyright © 1999 John Wiley & Sons, Ltd.
Characterization of GFP‐MAL expression and incorporation in rafts
Authors: Caduff J. , Sansano S. , Bonnet A. , Suter U. , Schaeren‐Wiemers N.
Published: August 2002

During myelin formation, membrane‐associated proteins have to be sorted and transported in specified membrane regions such as compact and non‐compact myelin membranes. One protein that may be involved in such a process is the Myelin and Lymphocyte protein MAL (VIP17/ MVP17). MAL was identified as a novel myelin membrane component expressed by oligodendrocytes and Schwann cells. Since MAL has been shown to be important in the apical sorting machinery of polarized cells, we have started to investigate the possible functional role of MAL in sorting myelin membrane‐associated molecules. In this study, we have generated cDNA constructs with green fluorescent protein (GFP) either at the N‐ or C‐terminus of MAL. Transfection experiments showed that GFP‐MAL expression resembles that of normal MAL, whereas the MAL‐GFP fusion construct was not properly transported within the cell. Furthermore, we could demonstrate that GFP‐MAL is enriched in detergent insoluble glycolipid‐enriched microdomains as already seen for untagged MAL. As a prerequisite for the generation of transgenic mice expressing GFP‐MAL under the control of its own regulatory elements, we have generated a cDNA construct with an 8‐kb MAL promotor fragment fused to GFP‐MAL. Transfection experiments of the Oli‐neu oligodendrocyte cell line showed that GFP‐MAL was expressed, but only in cells, which were stimulated for differentiation with cAMP. In summary, the results confirm that the fusion protein GFP‐MAL is incorporated into detergent‐insoluble complexes and the 8‐kb MAL promotor fragment is sufficient to be activated in oligodendrocytes. Microsc. Res. Tech. 52:645–655, 2001. © 2001 Wiley‐Liss, Inc.
Testing the vulnerability of the phylotypic stage: On modularity and evolutionary conservation
Authors: Galis Frietson , Metz Johan A.J.
Published: August 2002

The phylotypic stage is the developmental stage at which vertebrates most resemble each other. In this study we test the plausibility of the hypotheses of Sander [1983, Development and Evolution, Cambridge University Press] and Raff [1994, Early Life on Earth, Columbia University Press; 1996, The Shape of Life, University of Chicago Press] that the phylotypic stage is conserved due to the intense and global interactivity occurring during that stage. First, we test the prediction that the phylotypic stage is much more vulnerable than any other stage. A search of the teratological literature shows that disturbances at this stage lead to a much higher mortality than in other stages, in accordance with the prediction. Second, we test whether that vulnerability is indeed caused by the interactiveness and lack of modularity of the inductions or, alternatively, is caused by some particularly vulnerable process going on at that time. From the pattern of multiple induced anomalies we conclude that it is indeed the interactiveness that is the root cause of the vulnerability. Together these results support the hypotheses of Sander and Raff. We end by presenting an argument on why the absence of modularity in the inductive interactions may also be the root cause of the conservation of the much discussed temporal and spatial colinearity of the Hox genes. J. Exp. Zool. (Mol. Dev. Evol.) 291:195–204, 2001. © 2001 Wiley‐Liss, Inc.
Sex reversal and aromatase in the European pond turtle: Treatment with letrozole after the thermosensitive period for sex determination
Authors: Belaid Baya , Richard‐Mercier Noelle , Pieau Claude , Dorizzi Mireille
Published: August 2002

In the European pond turtle (Emys orbicularis), gonadal sex differentiation is temperature‐dependent. The temperature sensitive period (TSP) of gonadogenesis lies between stages 16 and 22 of embryonic development. Previous studies have shown that embryos incubated at 30°C, a temperature yielding 100% phenotypic females, can be sex reversed by treatments with an aromatase inhibitor administered during TSP or even somewhat after TSP (as of stage 22+).

The goal of the present study was to determine whether the ovary still retains male potential at later stages of embryonic development and whether the induced male characters persist after hatching. For this purpose, eggs of E. orbicularis were treated with letrozole, a nonsteroidal aromatase inhibitor, at or as of stages 23, 24 or 25, then gonadal aromatase activity in each individual and the related gonadal structure were studied at hatching (stage 26) and for one year after hatching. Two kinds of treatments were carried out: 1) repeated applications of 10 μg of letrozole in ethanolic solution onto the eggshell; and 2) a single injection of 10 μg of letrozole in olive oil. Similar results were obtained with either application or injection of the aromatase inhibitor. In treatments as of or at stage 23, individuals with gonadal aromatase activity lower than 20 fmoles/hour/gonad had ovotestes, i.e., 22% of the treated individuals. At hatching, the inner part of these ovotestes contained testicular cords and also mixed lacunae presenting various degrees of transdifferentiation of the epithelium into a Sertolian epithelium. The cortex was maintained, although some germ cells degenerated within it. These processes continued after hatching. However, at 12 months, gonads were still ovotestes displaying some follicles with a growing oocyte in the remaining parts of the cortex. In treatments as of or at stages 24 or 25, only a few individuals were masculinized. One had ovotestes; in others, the cortex was absent in some parts and when it was present oocytes were degenerating. These results show that in the European pond turtle, differentiation of ovotestes from ovaries can be induced by treatment with an aromatase inhibitor starting at late stages of embryonic development (between the end of TSP and hatching), although such differentiation is less frequent as embryonic development proceeds. Sex reversal persists for at least one year after hatching. J. Exp. Zool. 290:490–497, 2001. © 2001 Wiley‐Liss, Inc.
Obstruction sets for outer‐cylindrical graphs
Authors: Archdeacon Dan , Bonnington C. Paul , Dean Nathaniel , Hartsfield Nora , Scott Katherine
Published: August 2002

A graph is outer‐cylindrical if it embeds in the sphere so that there are two distinct faces whose boundaries together contain all the vertices. The class of outer‐cylindrical graphs is closed under minors. We give the complete set of 38 minor‐minimal non‐outer‐cylindrical graphs, or equivalently, an excluded minor characterization of outer‐cylindrical graphs. We also give the obstruction sets under the related topological ordering and Y Δ‐ordering. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 42–64, 2001
Comparative study of the cuticle in some aquatic oligochaetes (Annelida: Clitellata)
Authors: Gustavsson Lena M.
Published: August 2002

An examination of the cuticle of six aquatic oligochaete species using transmission electron microscopy revealed a larger morphological variation than previously known. Three freshwater species, Aulodrilus pluriseta, Spirosperma ferox (both Tubificidae), and Pristina breviseta (Naididae), and three marine species, Clitellio arenarius, Heterochaeta costata (both Tubificidae), and Paranais litoralis (Naididae), were investigated. The arrangement of the collagen fibers in the cuticle differs among the studied species. Only S. ferox shows an “orthogonal grid,” i.e., layers of parallel fibers perpendicular to each other, as earlier described for lumbricids and enchytraeids. Clitellio arenarius and H. costata have fibers arranged in layers, while A. pluriseta and P. litoralis have irregularly distributed fibers. Pristina breviseta lacks cuticular fibers. The matrix surrounding the collagen fibers (when present) continues outside the fiber layer, making up a thin epicuticle, which has a unique banding in each of the studied species. The external surface of the epicuticle is covered with epicuticular projections. Their number, shape, and attachment to the epicuticle vary among the studied species. Furthermore, a distinctive internal substructure of the projections was observed in H. costata, A. pluriseta, S. ferox, and P. breviseta. Microvilli, extensions from the epidermal cells, penetrate the cuticle and terminate at its outer surface. In three species microvilli were observed to pinch off the epicuticular projections. The size, number, and shape of the latter vary; no typical microvilli were observed in S. ferox. J. Morphol. 248:185–195, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of female intrapelvic tumors by clinical proton MR spectroscopy
Authors: Okada Toshiko , Harada Masafumi , Matsuzaki Kenji , Nishitani Hiromu , Aono Toshihiro
Published: August 2002

We measured metabolites in large tumors of the female pelvis (23 cases total: 6 malignant cases, 17 benign cases) using single‐voxel proton magnetic resonance (MR) spectroscopy and evaluated the clinical significance of this method in the differential diagnosis of female pelvic tumors. The characteristically obtained signal was lactate, which was detected not only in all the malignant tumors but also in some of the benign tumors. However, the lactate signals of the malignant tumors tended to form higher peaks than those of benign tumors, which was a finding consistent with the result of the earlier in vitro study reported in ovarian tumors. The signal of choline‐containing compounds (Cho) was found only in solid tumors, and the signal intensity varied among different histological types of tumors, possibly reflecting metabolic activity of the cell membrane. We considered that proton MR spectroscopy (MRS) of intrapelvic tumors would be useful for the diagnosis of the nature of female intrapelvic tumors. J. Magn. Reson. Imaging 2001;13:912–917. © 2001 Wiley‐Liss, Inc.
Functional MRI with simultaneous EEG recording: Feasibility and application to motor and visual activation
Authors: Lazeyras François , Zimine Ivan , Blanke Olaf , Perrig Stephen H. , Seeck Margitta
Published: August 2002

The possibility of combining the high spatial resolution of functional magnetic resonance imaging (fMRI) with the high temporal resolution of electroencephalography (EEG) may provide a new tool in cognitive neurophysiology, as well as in clinical applications such as epilepsy. However, the simultaneous recording of EEG and fMRI raises important practical problems: 1) the patients' safety, in particular the risk of skin burns due to electrodes heating; 2) the impairment of the EEG recording by the static magnetic field, as well as by RF and magnetic field gradients used during MRI; and 3) the quality of MR images, which may be affected by the presence of conductors and electronic devices in the MRI bore. Here we present our experiences on 19 normal volunteers who underwent combined fMRI and 16‐channel EEG examination. Consistent with previous reports, safety could be assured when performing EEG recordings during fMRI acquisition. Electrophysiological signals recorded with surface EEG were similar inside and outside the 1.5 T magnet. Furthermore, fMRI using motor or visual tasks revealed similar areas of activation when performed with and without 16‐channel EEG recording. J. Magn. Reson. Imaging 2001;13:943–948. © 2001 Wiley‐Liss, Inc.
Distribution of hepatitis C virus infection in liver biopsies from children and adults with chronic hepatitis C
Authors: de Lucas Susana , Bartolomé Javier , Rodríguez‐Iñigo Elena , Casqueiro Mercedes , Millán Antonio , Ruiz‐Moreno Mercedes , Oliva Horacio , Carreño Vicente
Published: August 2002

Chronic hepatitis C in children is characterized by milder forms of liver damage than those found in adults. Such a difference has been attributed to a low viral load in children that may lead to poor recognition of infected cells by the immune system. One approach that could be used to confirm this hypothesis may be to examine the number of infected hepatocytes in liver biopsies. Paraffin embedded liver biopsies from 21 children and 15 adults with chronic hepatitis C virus (HCV) infection (with a similar duration of the infection) were hybridized in situ and the percentage of infected hepatocytes was correlated with the histological activity index, alanine aminotransferase levels and HCV viraemia levels. Histological activity index and HCV viraemia levels were statistically higher (P < 0.05 and P < 0.01 respectively) in adults than in children, and the percentage of infected hepatocytes was higher in adults (11.0 ± 19.7%) than in children (4.6 ± 3.6%), although it did not reach statistical significance. Also, the percentage of infected hepatocytes correlated with HCV‐RNA concentration in serum in both children (r = 0.683, P = 0.001) and adults (r = 0.768, P = 0.001). The results show that liver damage in children with chronic hepatitis C is not related to the extent of infection in the liver. This findings support the hypothesis of that liver injury in chronic HCV infection is mediated by the host immune response. J. Med. Virol. 64:1–5, 2001. © 2001 Wiley‐Liss, Inc.
Genetic relatedness of Cuban HAV wild‐type isolates
Authors: Diaz Belkis I. , Sariol Carlos A. , Normann Andrea , Rodríguez Licel , Flehmig Bertram
Published: August 2002

Knowledge of the nucleotide sequence in the region of the putative VP1/2A junction of the Hepatitis A virus (HAV) genome has enabled differentiation of HAV strains and their classification into seven genotypes, in some of which sub‐genotypes A and B can be defined. A 168 base segment encompassing the putative VP1/2A junction of 27 clinical wild‐type isolates of HAV from Cuba was amplified by reverse transcriptase‐polymerase chain reaction and then sequenced. The Cuban isolates are clustered within sub‐genotype IA. A single amino acid substitution, which does not correspond with any of the reported changes for other strains, was observed. A new sub‐genotype variant is therefore postulated. This study provides new data on the genetic relatedness of HAVs from Cuba and on the distribution of sub‐genotype IA in the Caribbean area. J. Med. Virol. 64:96–103, 2001. © 2001 Wiley‐Liss, Inc.
Induction of mucosal IgA following intravaginal administration of inactivated HIV‐1‐capturing nanospheres in mice
Authors: Kawamura Masaki , Naito Taichi , Ueno Masamichi , Akagi Takami , Hiraishi Katsuya , Takai Izumi , Makino Masahiko , Serizawa Takeshi , Sugimura Kazuhisa , Akashi Mitsuru , Baba Masanori
Published: August 2002

Concanavalin A‐immobilized polystyrene nanospheres (Con A‐NS) were developed for the HIV‐1 vaccine capable of preventing sexual transmission. Con A‐NS could capture efficiently HIV‐1 irrespective of their cell tropism (R5 or X4). Furthermore, Con A‐NS captured equally infectious and heat‐inactivated HIV‐1. Inactivated HIV‐1‐capturing Con A‐NS (HIV‐NS) were intravaginally administered to mice. Heat‐inactivated HIV‐1 alone and Con A‐NS alone were also administered as control immunogens. Vaginal fluids were collected during and after immunization and analyzed for their anti‐HIV‐1 antibody levels. Although the anti‐HIV‐1 IgG antibody was undetectable in any groups, increased anti‐HIV‐1 IgA antibody response was identified in the vaginal fluids of immunized mice with HIV‐NS. The vaginal fluids obtained from the HIV‐NS‐administered mice showed neutralizing activity against the immunizing HIV‐1 strain. A marked difference in vaginal distribution was observed between HIV‐NS and other immunogens, and the toxicity of Con A was reduced by conjugation with nanospheres. Thus, HIV‐NS may have great potential as a prophylactic HIV‐1 vaccine and should be examined further for its efficacy in non‐human primates. J. Med. Virol. 66:291‐298, 2002. © 2002 Wiley‐Liss, Inc.
Hybrid modelling for echo location and surface characterization
Authors: de Cogan D. , Morton M. , Peel D. , Sant V.
Published: August 2002

The scattering of sound from surfaces by rotating sources such as the tips of helicopter rotor blades can be used as a method of locating and ranging obstructions which may represent a physical danger to the craft. Modelling such systems presents some difficulties but these can be overcome using a combination of TLM and phase‐coherent ray‐tracing. This paper describes the hybrid approach, particularly, the techniques for interfacing. The application to the specific problem of the scattering of rotor‐tip noise from realistic targets involved the use of a simple PML and surface‐conforming boundaries. Copyright © 2001 John Wiley & Sons, Ltd.
TLM‐based FDTD modelling of optical bistability
Authors: Hruskovec Tomislav , Chen Zhizhang
Published: August 2002

The TLM‐based FDTD method is extended to the modelling of optical bistability caused by the saturable Kerr‐effect of a GaAs–GaAsAl multiple quantum well (MQW) like medium. This structure is one of the possible candidates to be used as an all‐optical switch in high‐speed communication systems. The purpose of this paper is to demonstrate the capability of the TLM‐based FDTD method in handling the non‐linear medium problems, by performing a time‐domain simulation starting from the basic equations that represent the problem. A recursive formulation is derived to account for the saturable Kerr properties of the material and a physically realizable Fabry–Perot cavity is simulated. The numerical results confirm the effectiveness of the TLM‐based FDTD method for bistability modelling, and thus provide the foundations for further work and the simulation of more complicated and realistic bistable structures promising for high‐speed all‐optical digital signal processing. Copyright © 2001 John Wiley & Sons, Ltd.
Application of the argument principle method to the calculation of DFB laser diode modes
Authors: Barlow G. F. , Shore K. A.
Published: August 2002

A convenient technique for the exact determination of the longitudinal cavity modes of a distributed feed‐back (DFB) laser is presented. The method employs the argument principle method (APM) to find the singular points of the characteristic equation derived from consideration of the counter propagating coupled modes within the cavity. The method is applied to both linear and circular grating laser diodes. Copyright © 2001 John Wiley & Sons, Ltd.
Virtual analogue simulation of semiconductor lasers and photon transport transistors
Authors: Cheung W. N.
Published: August 2002

A behavioural modelling method is described for investigating various characteristics of single‐mode semiconductor lasers. The method is based on the rate equations associated with the device, and simulation is carried out using circuit analogues implemented on the software platform of PSpice. As illustrations of the method, simulation results including light‐current characteristics, charge number clamping, modulation response and transient behaviour of a typical laser diode are given. The virtual analogue simulation method has been applied to predict the behaviour of a class of opto‐electronic devices called photon transport transistors formed with appropriate current feedback to the laser diode. The results indicate that the PTT has an increased damping and a higher modulation sensitivity brought about by its current gain. In the use for driving laser diodes the PTT may result in improved pulse modulation characteristics. Copyright © 2001 John Wiley & Sons, Ltd.
ST8Sia IV mRNA corresponds with the biosynthesis of α2,8sialyl polymers but not oligomers in rat oligodendrocytes
Authors: Stoykova Lidia I. , Beesley Jacqueline S. , Grinspan Judith B. , Glick Mary Catherine
Published: August 2002

As oligodendrocytes mature they progress through a series of distinct differentiation steps characterized by the expression of specific markers. One such marker, polysialic acid found on the neural cell adhesion molecule (NCAM), is detected by antibodies and is present on progenitor oligodendrocytes, but is not detected to the same extent on mature oligodendrocytes. Two closely related polysialyltransferases, ST8Sia II (STX) and ST8Sia IV (PST) have been cloned previously and shown to synthesize polysialic acid on NCAM and other glycoproteins. To determine whether or not polyα2,8sialyltransferases are downregulated during the differentiation of oligodendrocytes, the enzyme activity and expression of ST8Sia II and ST8Sia IV mRNA at two stages of maturation in JS12/1 and JS3/16 oligodendrocytes were examined. Differentiation in both oligodendroglial cell lines was accompanied by more than a 50% reduction in the biosynthesis of polymers of α2,8sialic acid when fetuin was used as substrate. Most interestingly, extracts of JS12/1 mature cells synthesized 60% more short oligomers of α2,8sialic acid than the progenitor cells, whereas JS3/16 mature cells synthesized barely detectable amounts of the short oligomers. Transcripts for ST8Sia IV mRNA were present in both JS12/1 and JS3/16 and were reduced when the biosynthesis was markedly reduced. In contrast ST8Sia II mRNA was barely detectable in JS3/16 cells and although detectable in JS12/1 cells, there was no clear modulation with maturation. These results were supported by the examination of the brains of rats from embryonic to Day 21 ages. The enzyme activity and mRNA experiments show that polyα2,8sialyltransferase itself is down regulated to cause the reduction in sialyl polymers on mature oligodendrocytes. Moreover, ST8Sia IV is responsible for the polysialylation of NCAM in oligodendrocytes. J. Neurosci. Res. 66:497–505, 2001. © 2001 Wiley‐Liss, Inc.
Developmental changes in the protein composition of sphingolipid‐ and cholesterol‐enriched membrane domains of rat cerebellar granule cells
Authors: Palestini Paola , Botto Laura , Guzzi Francesca , Calvi Chiara , Ravasi Daniela , Masserini Massimo , Pitto Marina
Published: August 2002

The biological role of cell membrane domains has been investigated in a number of eukariotic cells, but less attention has been paid to the neuron. In the present investigation, we assessed the changes in lipid and protein composition of detergent‐resistant membrane fractions prepared from cultured rat cerebellar granule cells, during differentiation and maturation in vitro. At any stage of the cell life, low‐density, detergent‐resistant fractions, characterised by the specific presence of prion protein, were enriched in glycolipids, cholesterol, and sphingomyelin. The enrichment in sphingomyelin was developmentally regulated, increasing continuously during cell differentiation and maturation. Concerning proteins, domains were enriched in Fyn and TAG‐1, which present exclusively within this fraction at any stage of cell culture, and in GAP‐43, mainly during the differentiation stage. On the other side, proteins affecting signal transduction and cytoskeleton‐related proteins (heterotrimeric G‐proteins, protein kinase C, MARCKS, tubulin), were not enriched within detergent‐resistant fractions during cell differentiation, but were recovered within this fraction in mature neurons. These results indicate that during different cellular life stages, specific proteins are recruited within detergent‐resistant membrane domains of the neuron and suggest their involvement in specific physiological phenomena (differentiation, maturation and/or aging). © 2002 Wiley‐Liss, Inc.
Plasma membrane calcium ATPase plays a role in reducing Ca2+‐mediated cytotoxicity in PC12 cells
Authors: Garcia Michael L. , Usachev Yuriy M. , Thayer Stanley A. , Strehler Emanuel E. , Windebank Anthony J.
Published: August 2002

In many cell types, cell death induced by a variety of insults is accompanied by an increase in intracellular calcium. The Ca2+ homeostatic mechanisms affected by such insults, however, have not been fully determined. Recent evidence indicates that kainic acid‐induced seizures alter plasma membrane calcium ATPase mRNA expression within vulnerable hippocampal cell populations before the onset of cell death. We examined the effects of altering plasma membrane calcium ATPase expression on cell vulnerability in rat pheochromocytoma 12 cells. Pheochromocytoma 12 cells are vulnerable to Ca2+ overload induced by the Ca2+ ionophore A23187. Reverse transcriptase‐PCR and Western blot data indicated that plasma membrane calcium ATPase isoform 4b constitutes a major calcium pump isoform in the pheochromocytoma 12 cells. Therefore, permanently transfected pheochromocytoma 12‐derived cell lines were established that either over‐expressed plasma membrane calcium ATPase isoform 4b, or suppressed the expression of the endogenous plasma membrane calcium ATPase isoform 4. Over‐expressing clones were less vulnerable to Ca2+‐mediated cell death induced by A23187 whereas “antisense” clones were considerably more susceptible. These data indicate that regulation of plasma membrane calcium ATPase expression may be critical to cellular survival when cells are exposed to pathological increases in intracellular calcium. J. Neurosci. Res. 64:661–669, 2001. © 2001 Wiley‐Liss, Inc.
Interactions of cobalt tetrasulfophthalocyanine with thiolate anions in dimethylformamide
Authors: TYAPOCHKIN EDUARD M. , KOZLIAK EVGUENII I.
Published: August 2002

Thiolate complexes of cobalt tetrasulfophthalocyanine ( CoTSPc ), possible intermediates of the industrial removal of mercaptans from oil fractions (Merox process), were studied in dimethylformamide, dimethylsulfoxide, and other polar aprotic solvents by UV-vis, 1 H NMR, and ESR spectroscopy. All thiolates react with Co II TSPc under anaerobic conditions with 1:1 stoichiometry. All tested aliphatic thiolates, regardless of their basicity, reduce Co II TSPc to form Co I TSPc derivatives. Low-basicity thiolates also form unstable non-reduced ( RS -) Co II TSPc complexes as dead-end products. Indirect kinetic evidence was obtained for electron transfer from the axial ligand to metal via the phthalocyanine equatorial ligand. 1 H NMR and binding studies revealed sulfur–cobalt interactions in the Co I TSPc product, thus indicating an axial ligand attachment to Co I TSPc . Low-basicity aromatic thiolates (pentachloro- and pentafluorobenzenethiolate) form ( RS -) Co II TSPc complexes, which are stable toward intramolecular metal reduction. This effect is indicative of possible π-stacking between the aromatic thiolate and phthalocyanine ring.
X-ray structure determination of Ru(TPP)(CO)(MeIm)·2CHCl3
Authors: JENE PAUL G. , IBERS JAMES A.
Published: August 2002

The crystal structure of (carbonyl)(1-methylimidazole)(5,10,15,20-tetraphenylporphyrinato)ruthenium(II)·2chloroform, Ru ( TPP )( CO )( MeIm )·2 CHCl 3, an R-state model of the hemoglobin active site, has been determined. The material crystallizes in space group P21/c of the monoclinic system with four formula units in a cell of dimensions a = 12.733(2) Å, b = 14.535(2) Å, c = 24.921(2) Å, β = 91.15(1) ° at T = 110 K . The structure has been refined to R(F) = 0.038 for 588 variables and 7458 data. The Ru – C ( O ) distance is 1.835(3) Å and the Ru – N ( imidazole ) distance is 2.163(2) Å. This is the third reported crystal structure of a solvated Ru ( TPP )( CO )( MeIm ) compound. It differs from the other two in a larger displacement of 0.079(1) Å of the Ru atom from the mean porphyrin plane toward the CO ligand, a shorter Ru – N ( imidazole ) bond, a smaller average deviation, 0.06 Å, of atoms from the porphyrin plane, and the absence of a small ≤60 ° dihedral angle between the porphyrin plane and phenyl rings.
Tetrakis(selenodiazole)porphyrazines. 2: Metal complexes with Mn(II), Co(II), Ni(II), and Zn(II)
Authors: ANGELONI SILVIA , BAUER ELVIRA M. , ERCOLANI CLAUDIO , POPKOVA IRINA A. , STUZHIN PAVEL A.
Published: August 2002

The present report describes two series of new porphyrazine macrocycles derived from tetrakis(selenodiazole)porphyrazine, TSeDPzH 2, having the formulae [ TSeDPzM ]( CH 3 COOH )( H 2 O )x M = Mn (II), Co (II), Ni (II), Zn (II); x = 4–6) and [ TSeDPzM ( py )]( CH 3 COOH )( H 2 O )x ( M = Mn (II), Co (II), Ni (II); x = 1–5), obtained by reaction of the free ligand with the appropriate metal acetate in dimethyl (DMSO), and, respectively, pyridine. All the species isolated are stable-to-air substantially amorphous materials, almost completely insoluble in the usual organic solvents and N -donors (pyridine etc.), and only slightly soluble in CF3COOH or 96% H 2 SO 4. The complexes have been investigated by IR, Raman, and UV-vis spectra, and magnetic susceptibility measurements. Their properties in terms of electronic structure and reactivity towards N -bases are discussed in comparison with their S-containing analogs and the class of the structurally similar metal phthalocyanines.