bluuebunny/crossref_metadata_2025 huggingface dataset:
Laminin‐α2 but not ‐α1‐mediated adhesion of human (Duchenne) and murine (mdx) dystrophic myotubes is seriously defective
Authors: Angoli Damiano , Corona Paola , Baresi Rita , Mora Marina , Wanke Enzo
Published: October 2002

It has been suggested that α‐dystroglycan links the dystrophin‐associated protein complex and extracellular matrix and that the absence of dystrophin and α‐dystroglycan in Duchenne muscular dystrophy (DMD) may lead to the breakdown of this linkage. In the present study, myotubes from DMD patients and murine X‐linked muscular dystrophic mice (mdx) were used to measure their adhesive force to the physiological laminin‐α2 substrate, and it was found that the dystrophic myotubes were selectively unable to sustain adhesion. However, normal and dystrophic myotubes attached equally well to the laminin‐α1 substrate. As far as we know, this is the first experimental evidence that the absence of dystrophin causes the complete loss of a still unknown laminin‐α2‐dependent adhesion force, therefore suggesting that the primary consequence of Duchenne dystrophy consists of the loss of an authentic mechanical linkage at the level of the α‐dystroglycan/basal lamina interface.
High‐resolution immunogold cytochemistry indicates that AQP4 is concentrated along the basal membrane of parietal cell in rat stomach
Authors: Fujita Akikazu , Horio Yoshiyuki , Nielsen Søren , Nagelhus Erlend A , Hata Fumiaki , Ottersen Ole Petter , Kurachi Yoshihisa
Published: October 2002

Gastric parietal cells secrete hydrochloric acid in stomach. Because the secreted HCl solution is isotonic with the plasma fluid, it should accompany the water transport across the membranes of parietal cells. Aquaporins (AQPs) are water channel proteins that play the central role in the cellular handling of water in various mammalian tissues. Using immunocytochemistry, we found that AQP4 was expressed only in parietal cells of rat gastric mucosa. Immunogold electron microscopy study further demonstrated that AQP4 was mostly localized at the basal membrane of parietal cells. In the basal membrane, AQP4 was prominently enriched on the portion contacting with the basement membrane surrounding gastric glands. These results suggest that the contact between basement membrane and basal membrane may generate the signal involved in the targeting of AQP4 in gastric parietal cells.
Creation of a functional S‐nitrosylation site in vitro by single point mutation
Authors: Castro Carmen , Ruiz Félix A. , Pérez-Mato Isabel , Sánchez del Pino Manuel M. , LeGros Leighton , Geller Arthur M. , Kotb Malak , Corrales Fernando J. , M. Mato José
Published: October 2002

Here we show that in extrahepatic methionine adenosyltransferase replacement of a single amino acid (glycine 120) by cysteine is sufficient to create a functional nitric oxide binding site without affecting the kinetic properties of the enzyme. When wild‐type and mutant methionine adenosyltransferase were incubated with S‐nitrosoglutathione the activity of the wild‐type remained unchanged whereas the activity of the mutant enzyme decreased markedly. The mutant enzyme was found to be S‐nitrosylated upon incubation with the nitric oxide donor. Treatment of the S‐nitrosylated mutant enzyme with glutathione removed most of the S‐nitrosothiol groups and restored the activity to control values. In conclusion, our results suggest that functional S‐nitrosylation sites can develop from existing structures without drastic or large‐scale amino acid replacements.
Rho‐specific binding and guanine nucleotide exchange catalysis by KIAA0380, a Dbl family member
Authors: Rümenapp Ulrich , Blomquist Andrea , Schwörer Guntram , Schablowski Helge , Psoma Amalia , Jakobs Karl H.
Published: October 2002

Several guanine nucleotide exchange factors (GEFs) for Rho‐GTPases have been identified, all of them containing a Dbl homology (DH) and pleckstrin homology (PH) domain, but exhibiting different specificities to the Rho family members, Rho, Rac and Cdc42. We report here that KIAA0380, a protein with a tandem DH/PH domain, an amino‐terminal PDZ domain and a regulator of G protein signalling (RGS) homology domain, is a specific GEF for RhoA, but not for Rac1 and Cdc42, as determined by GDP release, guanosine 5′‐O‐(3‐thio)triphosphate (GTPγS) binding and protein binding assays. When expressed in J82 cells, DH/PH domain‐containing forms of KIAA0380 induced actin stress fibers, whereas expression of the RGS homology domain prevented lysophosphatidic acid (LPA)‐induced stress fiber formation.
The fMet‐tRNA binding domain of translational initiation factor IF2: role and environment of its two Cys residues
Authors: Misselwitz Rolf , Welfle Karin , Krafft Christoph , Welfle Heinz , Brandi Letizia , Caserta Enrico , Gualerzi Claudio O
Published: October 2002

Mutations of the cysteines (positions 668 and 714) were generated in the IF2 C domain of Bacillus stearothermophilus translation initiation factor IF2. The corresponding proteins were characterized functionally and structurally. Most (yet not all) amino acid replacements at both positions resulted in severe reduction of the fMet‐tRNA binding activity of IF2 C without grossly altering its structure. Our work demonstrates that: (a) both Cys residues are buried within an hydrophobic core and not accessible to protonation or chemical substitution, (b) neither Cys is functionally essential and (c) both Cys residues are located near the active site, probably without participating directly in fMet‐tRNA binding.
Conservation of the central proline‐rich (PxxP) motifs of human immunodeficiency virus type 1 Nef protein during the disease progression in two hemophiliac patients
Authors: Asamitsu Kaori , Morishima Takashi , Tsuchie Hideaki , Kurimura Takashi , Okamoto Takashi
Published: October 2002

The nef gene is considered to play a crucial role in the development of acquired immunodeficiency syndrome (AIDS). In this study, we analyzed the sequence of nef quasispecies obtained from replication‐competent HIV‐1 isolates from two Japanese hemophiliac patients infected with HIV‐1. At least 10 nef clones were isolated at each time point and a total of 75 individual nef quasispecies were sequenced. We observed a gradual increase in genetic diversity of the nef gene over time. Among the various functional regions of Nef protein, myristoylation site and the central PXXP (SH3 ligand) motifs were well conserved. The scattered regions responsible for downregulation of CD4 and class I MHC were also conserved. These data suggest that these functions of Nef may be involved throughout the disease process.
Up‐regulation of multidrug resistance‐associated protein 2 (MRP2) expression in rat hepatocytes by dexamethasone
Authors: Courtois Arnaud , Payen Léa , Guillouzo André , Fardel Olivier
Published: October 2002

Regulation of multidrug resistance‐associated protein (MRP2) expression in response to dexamethasone (DEX) was analyzed using mainly primary rat hepatocytes. Enhanced levels of MRP2 mRNAs associated with increased amounts of a 190 kDa MRP2 were found in cultured DEX‐treated hepatocytes; similarly, administration of DEX to rats (100 mg/kg, i.p.) led to a marked increase of hepatic amounts of MRP2 mRNAs. Maximal induction of MRP2 expression in DEX‐treated primary hepatocytes was reached with 10−5 M DEX, a concentration higher than that (10−7 M) required for maximal up‐regulation of tyrosine aminotransferase (TAT), a typical glucocorticoid receptor‐regulated enzyme. In addition, the anti‐glucocorticoid compound RU486 failed to inhibit MRP2 induction caused by DEX whereas it fully blocked that of TAT. These findings therefore demonstrate that DEX is a potent inducer of MRP2 expression in rat hepatocytes through a mechanism that seems not to involve the classical glucocorticoid receptor pathway.
PcpA, which is involved in the degradation of pentachlorophenol in Sphingomonas chlorophenolica ATCC39723, is a novel type of ring‐cleavage dioxygenase
Authors: Ohtsubo Yoshiyuki , Miyauchi Keisuke , Kanda Kenji , Hatta Takashi , Kiyohara Houzo , Senda Toshiya , Nagata Yuji , Mitsui Yukio , Takagi Masamichi
Published: October 2002

The pentachlorophenol (PCP) mineralizing bacterium Sphingomonas chlorophenolica ATCC39723 degrades PCP via 2,6‐dichlorohydroquinone (2,6‐DCHQ). The pathway converting PCP to 2,6‐DCHQ has been established previously; however, the pathway beyond 2,6‐DCHQ is not clear, although it has been suggested that a PcpA plays a role in 2,6‐DCHQ conversion. In this study, PcpA expressed in Escherichia coli was purified to homogeneity and shown to have novel ring‐cleavage dioxygenase activity in conjunction with hydroquinone derivatives, and converting 2,6‐DCHQ to 2‐chloromaleylacetate.
Mass production of basal bodies in paraspermiogenesis of Tubificinae (Annelida, Oligochaeta)
Authors: Ferraguti Marco , Fascio Umberto , Boi Silvia
Published: October 2002

The oligochaete annelids, belonging to the subfamily Tubificinae, produce two types of spermatozoa: eusperm (the fertilising ones) and parasperm, protecting and carrying the eusperm. The pathway for the production of the two types is common until the onset of meiosis, but then a regular meiosis produces eusperm, whereas parasperm is generated through a peculiar mechanism of nuclear fragmentation giving rise to an irregular, but very high, number of paraspermatozoa. Since every parasperm has its own flagellum, this entails the necessity of producing a very high number of basal bodies. In the present paper, we describe how basal bodies are generated through a mechanism similar to that producing the basal bodies in ciliated epithelia, but never observed up to now during the genesis of a uniflagellated cell. Basal bodies form in close proximity to a precursor structure called deuterosome, which originates de novo in the cytoplasm from fibrogranular material. The various stages of centriologenesis are positive to anti‐centrin antibodies and, observed by electron microscopy, correspond closely to the ones described for ciliated epithelia. However, once formed, the basal bodies migrate to their final position and produce the parasperm flagellum.
Barriers to the management of international operations
Authors: Klassen Robert D. , Whybark D.Clay
Published: October 2002

The purpose of this research was to define and rank key barriers to the effective management of international manufacturing operations. An international panel of experts, composed of practitioners, academics and consultants, was surveyed using a Delphi process to identify the key barriers, to explain the rationale for their selection and to rank them. The highest ranked barrier was general lack of a global view by management. Among the other highly ranked barriers were contemporary managerial issues like manufacturing strategy and managing international factory networks. Some traditional technical concerns like cultural and language differences and managing global logistics were also highly ranked. The responses clustered into two groups with the largest group focusing more heavily on contemporary manufacturing concerns while the other group emphasized more traditional technical topics. The results help establish priorities for developing research agendas, orienting teaching programs and focusing company resources.
On the spatially homogeneous Boltzmann equation
Authors: Mischler Stéphane , Wennberg Bernst
Published: October 2002

We consider the question of existence and uniqueness of solutions to the spatially homogeneous Boltzmann equation. The main result is that to any initial data with finite mass and energy, there exists a unique solution for which the same two quantities are conserved. We also prove that any solution which satisfies certain bounds on moments of order

s < 2

must necessarily also have bounded energy.

A second part of the paper is devoted to the time discretization of the Boltzmann equation, the main results being estimates of the rate of convergence for the explicit and implicit Euler schemes.

Two auxiliary results are of independent interest: a sharpened form of the so called Povzner inequality, and a regularity result for an iterated gain term.

Dans cet article nous nous intéressons aux problèmes d’existence et d’unicité pour l’équation de Boltzmann homogène. Nous montrons que pour toute donnée initiale de masse et d’énergie bornées il existe une unique solution qui conserve ces deux quantités. Nous montrons aussi que si une solution possède certains moments d’ordre

s < 2

alors nécessairement elle a une énergie initiale bornée.

Dans un deuxième temps nous montrons que les schémas d’Euler explicite et implicite de discrétisation en temps de l’équation convergent et nous donnons des taux de convergence.

Pour établir ces résultats nous utilisons de nouvelles inégalités de Povzner, ainsi qu’un lemme de régularité pour le terme de gain itéré.
The treatment of experimental osteomyelitis by surgical debridement and the implantation of calcium sulfate tobramycin pellets
Authors: Nelson Carl L. , McLaren Sandra G. , Skinner Robert A. , Smeltzer Mark S. , Thomas J. Roby , Olsen Keith M.
Published: October 2002

Calcium sulfate was used as a biodegradable delivery system for the administration of antibiotics in musculoskeletal infection. New Zealand white rabbits were infected with Staphylococcus aureus, debrided, and randomized to one of four treatment groups: calcium sulfate pellets with 10% tobramycin sulfate, placebo calcium sulfate pellets and IM tobramycin, placebo calcium sulfate pellets, or debridement. Serum and wound exudate tobramycin concentrations and serum calcium levels were measured. Radiographs, cultures, and histology were analyzed for efficacy and treatment. Rabbits treated with 10% tobramycin sulfate pellets showed a significantly higher eradication of infection (11/13) than rabbits treated with debridement only (5/12), placebo pellets and IM tobramycin (5/14), or placebo pellets (3/13). In the group receiving 10% tobramycin sulfate pellets, serum tobramycin concentrations peaked 3 h post‐operatively at 5.87 μg/ml and were non‐detectable after day 1. In the group receiving placebo pellets and IM tobramycin, serum concentrations peaked at 7.82 μg/ml 1 h post‐operatively, fell to 6.12 μg/ml on day 2, and averaged 4.18 μg/ml for the remainder of the treatment period. The wound exudate tobramycin concentrations in the animals treated with tobramycin sulfate pellets peaked at 11.9 mg/ml on day 1 and dropped to 2.5 μg/ml on day 7. There was no significant difference in the serum calcium levels in any of the treatment groups. Calcium sulfate containing tobramycin sulfate has potential utility as a biodegradable local antibiotic delivery system in the treatment of musculoskeletal infections.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Remodeling of the gliding surface after flexor tendon repair in a canine model in vivo
Authors: Zhao Chunfeng , Amadio Peter C. , Momose Toshimitsu , Zobitz Mark E. , Couvreur Paulus , An Kai‐Nan
Published: October 2002

Maintaining a smooth lubricated surface between the flexor tendon and sheath after tendon repair is very important for restoration of digit function. We studied the tendon surface after tendon repair mechanically in a canine model in vivo by measuring frictional force. One hundred and twenty flexor digitorum profundus (FDP) tendons were lacerated to 80% of their cross‐section and repaired with either a modified Kessler (MK) or Becker (MGH) repair. The postoperative therapeutic regimen was either synergistic wrist and digit motion (SWM) or passive digit flexion and extension with the wrist fixed in 45° of flexion (FIX). The dogs were sacrificed at one, three, or six weeks postoperatively. Thirty six FDP tendons from normal paws served as the control group, with each control tendon tested in two different conditions: intact and immediately after partial laceration and repair (0 time), making a total of five different timing points (intact, 0 time, one week, three weeks, and six weeks) for each repair type and each postoperative therapy. Frictional force between tendon and proximal pulley was evaluated after breaking any adhesions. Compared to intact tendons, friction was significantly increased immediately after tendon repair. The friction of the MK repair was significantly less than that of the MGH repair at all time and therapy groups, except at six weeks in the SWM group. For the MGH repair, at six weeks friction in the SWM group was significantly less than friction in the FIX group. This study showed that postoperative tendon gliding depends on the method of tendon repair and the postoperative therapy regimen. Furthermore, we have demonstrated that the gliding surface after tendon repair remodels with time. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Predictors of noncompliance in males with first-episode schizophrenia, schizophreniform and schizoaffective disorder
Authors: Novak-Grubic Virginija , Tavcar Rok
Published: October 2002

Purpose

Many factors influencing compliance in schizophrenia have been reported in the literature. Our aim was to assess predictors of noncompliance in male patients with first-episode schizophrenia, schizophreniform and schizoaffective disorder in a naturalistic setting.

Subjects and methods

Fifty-six male patients, discharged from hospital, were included in a 1-year follow-up study. Psychopathological symptoms were assessed with positive and negative syndrome scale at admission and discharge, while extrapyramidal side effects were recorded weekly during hospitalisation using the Simpson–Angus and Barnes akathisia scales. Socio-demographic and some other variables were also recorded.

Results

Thirty patients (53.6%) dropped out of treatment in the first year and 21 of them relapsed. With the Cox survival analysis three predictors of noncompliance were found: diagnosis of schizophrenia versus the other two diagnoses, positive symptoms at admission, and lack of insight at discharge.

Discussion

In spite of a specific methodology and selection of only first-episode male patients, the results are in accordance with the findings of other authors. This confirms the universality of noncompliance in psychotic patients.

Conclusions

First-episode patients have a high dropout rate. However, in compliant patients, the relapse rate was low, and therefore special attention and compliance-promoting interventions in first-episode patients are needed.
Scattering of electromagnetic waves in a magnetized plasma with an HF pump
Authors: PAVLENKO V. N. , PANCHENKO V. G. , NAZARENKO S. A.
Published: October 2002

The scattering of transverse electromagnetic waves by turbulent density
fluctuations in a magnetized plasma in the presence of external pump fields is
investigated. The case where a lower-hybrid pump wave decays into daughter and
ion-cyclotron waves in a plasma with ion-temperature anisotropy is considered.
The situation where an upper-hybrid pump wave parametrically excites modified
convective cells and electron drift waves is also analyzed. The differential scattering
cross-sections in the region above the parametric instability thresholds for these
three cases are calculated.
Alfvén wings in nonuniform plasmas: analysis using curvilinear coordinates
Authors: SALLAGO P. A. , PLATZECK A. M.
Published: October 2002

The results of a previous work, which describes in the magnetohydrodynamic
approximation Alfvén wings in nonuniform plasmas, are extended in order
to consider more general variations of the background fields. As mathematical
tools we use general curvilinear coordinates and stream functions. We prove the
possibility of existence of Alfvén wings when the background fields have cylindrical
or helical symmetry. For the former, the wings are cylinders, and for the latter, they
have helicoidal form; this last includes the case of uniform background fields. We
also obtain the relations among the different physical magnitudes in the wing.
Occurrence of tropical affinity fish in Galician waters, north-west Spain
Authors: Bañón R. , del Rio J.L. , Piñeiro C. , Casas M.
Published: October 2002

Four new fish species have been recorded for the first time in the last few years in Galician waters: Physiculus dalwigkii, Neoscopelus microchir, Gaidropsarus granti and Pisodonophis semicinctus. The captures of Physiculus dalwigki, N. microchir and G. granti represent a new northern limit for their distribution in the north-east Atlantic, increasing their geographical range of distribution considerably while the capture of Pisodonophis semicinctus is the second record for the Atlantic European waters.
Butyltin and phenyltin compounds in eels (Anguilla anguilla)
Authors: Harino H. , O'Hara S.C.M. , Burt G.R. , Pope N.D. , Chesman B.S. , Langston W.J.
Published: October 2002

Tributyltin (TBT) and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), together with triphenyltin (TPT), were investigated in eels from the Thames Estuary and the Weston Canal (Merseyside). Within individual eels, the concentrations of organotin (OT) compounds varied considerably between tissues. Tributyltin concentrations were highest in heart and gall bladder and lowest in muscle and gonad. Tributyltin was generally the most predominant of butyltin (BT) compounds present in eel tissues and DBT the least. Phenyltins were detected in eels from both locations, notably the Weston Canal where TPT was present up to 0.367 μg g−1 (as Sn) in liver samples. Concentrations of OTs in liver (and muscle) were independent of weight and length in the eel populations examined. In a survey of OTs in eel populations along the Thames Estuary hepatic TBT levels ranged from 0.066–0.347 μg g−1 dry wt (as Sn) in liver of eels and were generally highest in the mid-section of the estuary, resembling the distribution pattern of TBT in sediment. Proportions of TBT to total BTs were also elevated in eel from this section of the waterway, consistent with continuing inputs in this region, albeit at relatively low levels. Major sewage treatment plants are sited here and may represent a possible source.
First record of the Indo-Pacific gastropod Melibe fimbriata in the Adriatic Sea
Authors: Despalatović Marija , Antolić Boris , Grubelić Ivana , Žuljević Ante
Published: October 2002

The specimens of Melibe fimbriata were found during October 2001 in Stari Grad Bay (Island of Hvar, Croatia) in Cymodocea nodosa and Posidonia oceanica beds on sandy and sandy–muddy bottoms at depths of 2 to 15 m. Presently, this is the northernmost record of this lessepsian immigrant in the Mediterranean basin.
SHOULD PRISONERS HAVE A RIGHT TO VOTE?
Authors: MBODLA NTUSI
Published: October 2002

This article raises a number of issues, such as voting rights in general and the extent that government should go to ensure that all are able to exercise this right in a democracy. Also raised is the issue of prisoners' rights. Finally, the peculiarities of the South African prison system are at issue here too. The article will examine prisoners' voting rights in general elections. Provincial and local government elections are somewhat different and will not be discussed.
Contextualizing the Knútsdrápur: skaldic praise-poetry at the court of Cnut
Authors: Townend Matthew
Published: October 2002

It is generally recognized that during the reign of Cnut the Danish king's court
came to represent the focal point for skaldic composition and patronage in the
Norse-speaking world. According to the later Icelandic Skáldatal or ‘List of
Poets’, no fewer than eight skalds were remembered as having composed for
Cnut: Sigvatr Þórðarson, Óttarr svarti, Þórarinn loftunga, Hallvarðr háreksblesi,
Bersi Torfuson, Steinn Skaptason, Arnórr Þórðarson jarlaskáld, and Óðarkeptr.
Comparing this list with the extant poetic remains, one arrives at the following
collection of skaldic praise-poems (some fragmentary) in honour of Cnut:
Sigvatr Þórðarson's Knútsdrápa; Óttarr svarti's Knútsdrápa; Hallvarðr háreksblesi's
Knútsdrápa; Þórarinn loftunga's Ho˛fuðlausn and Tøgdrápa; and (probably)
a fragment by Arnórr jarlaskáld. Of the other poets cited in Skáldatal, no verse in
honour of Cnut is extant by Bersi Torfuson, and none at all by Steinn Skaptason
and Óðarkeptr.
Underreporting of malaria incidence in the Netherlands: results from a capture–recapture study
Authors: VAN HEST N. A. H. , SMIT F. , VERHAVE J. P.
Published: October 2002

The aim of this study was to estimate the completeness of notification of malaria by physicians and laboratories in the Netherlands in 1996. We used a capture–recapture (CRC) analysis of three incomplete, partially overlapping registers of malaria cases: a laboratory survey, the Notification Office and the hospital admission registration. The response of the laboratories was 83.2%. In 1996 the laboratories microscopically identified 535 cases of malaria, 330 patients with malaria were admitted to hospital and physicians notified 311 malaria cases. 667 malaria cases were recorded in at least one register. CRC analysis estimated the total number of malaria cases at 774 (95% CI of 740–821). This implies a completeness of notification of 40.2% for physicians and 69.1% for the laboratories. It can be concluded that laboratory-based notification can considerably increase the number of officially reported malaria cases as compared to notification by physicians. However, possibly one-third of the cases may still go unreported.
An outbreak of viral gastroenteritis following environmental contamination at a concert hall
Authors: EVANS M. R. , MELDRUM R. , LANE W. , GARDNER D. , RIBEIRO C. D. , GALLIMORE C. I. , WESTMORELAND D.
Published: October 2002

In January 1999, an outbreak of viral gastroenteritis affected more than 300 people who attended a metropolitan concert hall over a 5-day period. Norwalk-like virus (NLV) was confirmed in faecal samples by reverse transcription polymerase chain reaction assay. The index case was a concert attendee who vomited in the auditorium and adjacent male toilet. Gastrointestinal illness occurred among members of 8/15 school parties who attended the following day. Children who sat on the same level of the auditorium as the index case were much more likely to be ill than those seated elsewhere (relative risk 7.1, 95% confidence interval 5.4–9.2, P<0.001). The majority of other reported cases had not been present on the evening of the vomiting incident. Disinfection procedure was poor and the disinfectant used contained no sodium hypochlorite. Transmission most likely occurred through direct contact with contaminated fomites. The outbreak has implications for disinfection procedures following vomiting incidents at public venues.
Environmental chemical effects on testicular function
Authors: Fowler PA , Murray T , Abramovich DR , Haites N , Lea RG
Published: October 2002

There have been a number of reviews on this topic over the past decade, starting with Carlsen et al. and including Irvine et al. and Murray et al., concerning declining male fertility. The most exhaustive has perhaps been that of Toppari et al. The main findings of these reviews are: (1) that in some countries of the world sperm production has halved in the last 60 years, (2) rates of testicular cancer have doubled, (3) rates of malformation of the male reproductive tract, such as hypospadias, have doubled, (4) rates of testicular maldescent have risen sharply and (5) these effects are largely linked geographically. Typically, endocrine disrupting chemicals (EDCs) in the environment have been regarded as the main candidates for these effects. A consistent problem with the field, however, is the difficulty in determining the accuracy of data relating to changes in men's health over the latter half of the 20th century. Advances in diagnosis and changing attitudes to the emotive issues surrounding deformity and male infertility inevitably render some of the mass of collected data suspect. Indeed a recent review of testicular and prostate cancer concluded that while the incidence of prostate cancer had increased, the epidemiological data were not suitable for concrete conclusions about causation to be drawn. However, in the case of testicular cancer the data suggested a limited number of major risk factors. In addition, assessing urogenital malformation retrospectively from patient notes is subject to considerable variation in classification. A recent review does however find evidence to suggest that trends of increasing incidences of hypospadias on a temporal and geographical basis may reflect an actual increase in incidence and require further study. On the other hand, there is a considerable body of evidence for EDC disruption of reproduction in wildlife (reviewed by Guillette & Gunderson, 2001).
Differential Expression of Two Distinct Phenylalanine Ammonia-Lyase Genes in Condensed Tannin-Accumulating and Lignifying Cells of Quaking Aspen
Authors: Kao Yu-Ying , Harding Scott A. , Tsai Chung-Jui
Published: October 2002

Lignins, along with condensed tannins (CTs) and salicylate-derived phenolic glycosides, constitute potentially large phenylpropanoid carbon sinks in tissues of quaking aspen (Populus tremuloides Michx.). Metabolic commitment to each of these sinks varies during development and adaptation, and depends onl-phenylalanine ammonia-lyase (PAL), an enzyme catalyzing the deamination of l-phenylalanine to initiate phenylpropanoid metabolism. In Populus spp., PAL is encoded by multiple genes whose expression has been associated with lignification in primary and secondary tissues. We now report cloning two differentially expressed PAL cDNAs that exhibit distinct spatial associations with CT and lignin biosynthesis in developing shoot and root tissues of aspen. PtPAL1 was expressed in certain CT-accumulating, non-lignifying cells of stems, leaves, and roots, and the pattern of PtPAL1 expression varied coordinately with that of CT accumulation along the primary to secondary growth transition in stems. PtPAL2 was expressed in heavily lignified structural cells of shoots, but was also expressed in non-lignifying cells of root tips. Evidence of a role forPt4CL2, encoding 4-coumarate:coenzyme A ligase, in determining CT sink strength was gained from cellular co-expression analysis with PAL1 and CTs, and from experiments in which leaf wounding increased PAL1 and4CL2 expression as well as the relative allocation of carbon to CT with respect to phenolic glycoside, the dominant phenolic sink in aspen leaves. Leaf wounding also increased PAL2and lignin pathway gene expression, but to a smaller extent. The absence of PAL2 in most CT-accumulating cells provides in situ support for the idea that PAL isoforms function in specific metabolic milieus.
Inventory and Functional Characterization of the HAK Potassium Transporters of Rice
Authors: Bañuelos Marı́a A. , Garciadeblas Blanca , Cubero Beatriz , Rodrı́guez-Navarro Alonso
Published: October 2002

Plants take up large amounts of K+ from the soil solution and distribute it to the cells of all organs, where it fulfills important physiological functions. Transport of K+from the soil solution to its final destination is mediated by channels and transporters. To better understand K+ movements in plants, we intended to characterize the function of the large KT-HAK-KUP family of transporters in rice (Oryza sativacv Nipponbare). By searching in databases and cDNA cloning, we have identified 17 genes (OsHAK1–17) encoding transporters of this family and obtained evidence of the existence of other two genes. Phylogenetic analysis of the encoded transporters reveals a great diversity among them, and three distant transporters, OsHAK1, OsHAK7, and OsHAK10, were expressed in yeast (Saccharomyces cerevisiae) and bacterial mutants to determine their functions. The three transporters mediate K+ influxes or effluxes, depending on the conditions of the experiment. A comparative kinetic analysis of HAK-mediated K+ influx in yeast and in roots of K+-starved rice seedlings demonstrated the involvement of HAK transporters in root K+ uptake. We discuss that all HAK transporters may mediate K+ transport, but probably not only in the plasma membrane. Transient expression of the OsHAK10-green fluorescent protein fusion protein in living onion epidermal cells targeted this protein to the tonoplast.
Neural Correlates for Perception of 3D Surface Orientation from Texture Gradient
Authors: Tsutsui Ken-Ichiro , Sakata Hideo , Naganuma Tomoka , Taira Masato
Published: October 2002

A goal in visual neuroscience is to reveal how the visual system reconstructs the three-dimensional (3D) representation of the world from two-dimensional retinal images. Although the importance of texture gradient cues in the process of 3D vision has been pointed out, most studies concentrate on the neural process based on binocular disparity. We report the neural correlates of depth perception from texture gradient in the cortex. In the caudal part of the lateral bank of intraparietal sulcus, many neurons were selective to 3D surface orientation defined by texture gradient, and their response was invariant over different types of texture pattern. Most of these neurons were also sensitive to a disparity gradient, suggesting that they integrate texture and disparity gradient signals to construct a generalized representation of 3D surface orientation.
High Abrasion Resistance with Sparse Mineralization: Copper Biomineral in Worm Jaws
Authors: Lichtenegger Helga C. , Schöberl Thomas , Bartl Michael H. , Waite Herbert , Stucky Galen D.
Published: October 2002

Biominerals are widely exploited to harden or stiffen tissues in living organisms, with calcium-, silicon-, and iron-based minerals being most common. In notable contrast, the jaws of the marine bloodworm
Glycera dibranchiata
contain the copper-based biomineral atacamite [Cu
2
(OH)
3
Cl]. Polycrystalline fibers are oriented with the outer contour of the jaw. Using nanoindentation, we show that the mineral has a structural role and enhances hardness and stiffness. Despite the low degree of mineralization, bloodworm jaws exhibit an extraordinary resistance to abrasion, significantly exceeding that of vertebrate dentin and approaching that of tooth enamel.
Sialoside clusters as potential ligands for siglecs (sialoadhesins)
Authors: Gan Zhonghong , Roy René
Published: October 2002

Clusters of O- and S-linked α-sialosides with valencies of two to four were constructed to serve as potential multivalent inhibitors towards sialoadhesins (siglecs). Thus, O- and S-prop-2-ynyl α-sialosides (3, 7), together with 4-iodophenyl sialoside 5 were prepared from acetochloroneuraminic acid derivative 1 using silver salicylate and propargyl alcohol for 3 and phase-transfer catalysis for 5 and 7, respectively. Oxidative acetylenic homocoupling of 3 and 7 under Glaser conditions (CuCl, O2) provided 1,3-diynes 8 and 9 in 83-86% yields. Palladium catalyzed cross-coupling of O-prop-2-ynyl sialoside 3 with 5 using Pd2(dba)3 and PPh3 gave nonsymmetrical dimer 10 (82%). Alternatively, symmetrical clusters were then prepared as above under Sonogashira cross-coupling conditions with 1,4-diiodobenzene (11), 1,3,5-triodobenzene (14), and finally 1,2,4,6-tetraiodobenzene (17) to provide both O- and S-linked dimers 12 (93%) and 13 (88%), trimers 15 (81%) and 16 (76%), while only O-linked tetramer 18 was prepared in 87% yield. Finally, treatment of the O-linked prop-2-ynyl sialoside 3 with Grubbs' metathesis catalyst Cl2Ru(PCy3)2=CHPh (19) gave, as expected, benzeneannulation regioisomeric trimers 20a, 20b in 68% yield.Key words: siglec, sialoadhesins, sialic acid, Sonogashira, palladium cross-coupling.
Impact du drainage forestier après coupe sur la croissance de l'épinette noire en forêt boréale
Authors: Jutras Sylvain , Bégin Jean , Plamondon André P
Published: October 2002

The objective of this study was to retrospectively evaluate, with the help of stem analysis, the growth increases of natural and planted black spruce (Picea mariana (Mill.) BSP) seedlings in 39 drainage networks located in Quebec public boreal forest and drained operationally after cutting. The ecological conditions of the sites have been described using the forest ecosystem classification for the Clay Belt of eastern Ontario. A significant effect of the drainage on 9-year periodic growth in diameter and height of natural black spruce seedlings, varying with distance from the ditch and ecological conditions, was observed. Stocking of natural black spruce seedlings was sufficient to insure the reconstruction of a forest stand both on the treated sites and on the control sites. The 5-year height growth increment of planted black spruce seedlings was weaker than that of the natural seedlings, which were located on the same sites, and it varied with distance from the ditches.
Forest age and management effects on epiphytic bryophyte communities in Adirondack northern hardwood forests, New York, U.S.A.
Authors: McGee Gregory G , Kimmerer Robin W
Published: October 2002

The objective of this study was to assess the influence of substrate heterogeneity on epiphytic bryophyte communities in northern hardwood forests of varying disturbance histories. Specifically, we compared bryophyte abundance (m2·ha1) and community composition among partially cut; maturing, 90- to 100-year-old, even-aged; and old-growth northern hardwood stands in Adirondack Park, New York, U.S.A. Total bryophyte cover from 0 to 1.5 m above ground level on trees [Formula: see text]10 cm diameter at breast height (DBH) did not differ among the three stand types. However, bryophyte community composition differed among host tree species and among stand types. Communities in partially cut and maturing stands were dominated by xerophytic bryophytes (Platygyrium repens, Frullania eboracensis, Hypnum pallescens, Brachythecium reflexum, Ulota crispa), while old-growth stands contained a greater representation of calcicoles and mesophytic species (Brachythecium oxycladon, Anomodon rugelii, Porella platyphylloidea, Anomodon attenuatus, Leucodon brachypus, Neckera pennata). This mesophyte-calcicole assemblage occurred in all stand types but was limited by the abundance of large-diameter (>50 cm DBH), thick-barked, hardwood host trees (Acer saccharum Marsh., Tilia americana L., Fraxinus americana L.). This study suggested that epiphytic bryophyte diversity can be sustained and enhanced in managed northern hardwood forests by maintaining host tree species diversity and retaining large or old, thick-barked residual hardwood stems when applying even-aged and uneven-aged silviculture systems.
Information-Geometric Measure for Neural Spikes
Authors: Nakahara Hiroyuki , Amari Shun-ichi
Published: October 2002

This study introduces information-geometric measures to analyze neural firing patterns by taking not only the second-order but also higher-order interactions among neurons into account. Information geometry provides useful tools and concepts for this purpose, including the orthogonality of coordinate parameters and the Pythagoras relation in the Kullback-Leibler divergence. Based on this orthogonality, we show a novel method for analyzing spike firing patterns by decomposing the interactions of neurons of various orders. As a result, purely pairwise, triple-wise, and higher-order interactions are singled out. We also demonstrate the benefits of our proposal by using several examples.
Robust Regression with Asymmetric Heavy-Tail Noise Distributions
Authors: Takeuchi Ichiro , Bengio Yoshua , Kanamori Takafumi
Published: October 2002

In the presence of a heavy-tail noise distribution, regression becomes much more difficult. Traditional robust regression methods assume that the noise distribution is symmetric, and they downweight the influence of so-called outliers. When the noise distribution is asymmetric, these methods yield biased regression estimators. Motivated by data-mining problems for the insurance industry, we propose a new approach to robust regression tailored to deal with asymmetric noise distribution. The main idea is to learn most of the parameters of the model using conditional quantile estimators (which are biased but robust estimators of the regression) and to learn a few remaining parameters to combine and correct these estimators, to minimize the average squared error in an unbiased way. Theoretical analysis and experiments show the clear advantages of the approach. Results are on artificial data as well as insurance data, using both linear and neural network predictors.
Refinement of hydrogen positions in natural chondrodite by powder neutron diffraction: implications for the stability of humite minerals
Authors: Berry A. J. , James M.
Published: October 2002

The structure of a natural sample of chondrodite (Mg4.89Fe0.07Si2.04O8F1.54(OH)0.46) was refined using powder neutron diffraction data and the Rietveld technique (P21/b;Z= 2;a= 4.7204(1)Å;b= 10.2360(3)Å;c= 7.8252(2)Å; α = 109.11(1)°;V= 357.26(2)Å3). Hydrogen was found to occupy the H1 site. The significance of hydrogen at this site is discussed in terms of hydrogen-bond stabilization of humite structures containing varying amounts of OH, F and Ti. Arguments are proposed as to why the F and Ti contents of natural humites usually result in only one H per formula unit when there is no crystal-chemical reason why fully hydrated samples should not be favoured.
Trafficking machinery of NKT cells: shared and differential chemokine receptor expression among Vα24+Vβ11+ NKT cell subsets with distinct cytokine-producing capacity
Authors: Kim Chang H. , Johnston Brent , Butcher Eugene C.
Published: October 2002

Natural killer T (NKT) cells are important regulators of the immune system, but their trafficking machinery, including expression of chemokine receptors, has been poorly defined. Unlike other conventional T-cell populations, we show that most NKT cells express receptors for extralymphoid tissue or inflammation-related chemokines (CCR2, CCR5, and CXCR3), while few NKT cells express lymphoid tissue–homing chemokine receptors (CCR7 and CXCR5). A population with homing potential for lymph nodes (L selectin+ CCR7+) exists only within a small subset of CD4 NKT cells. We show differential expression of chemokine receptors among NKT cell subsets: CCR4 is mainly expressed by a high cytokine (interleukin-4/interleukin-2)–producing (CD4) NKT subset, while CCR1, CCR6, and CXCR6 are preferentially expressed by the low cytokine-producing CD8 and CD4−CD8− subsets. In line with this, TARC/CCL17 (a CCR4 ligand) induces preferential chemotaxis of the CD4 NKT subset, while chemotactic activities of LARC/CCL20 (a CCR6 ligand) and MIP-1α/CCL3 (a CCR1 ligand) are focused on the CD8 and CD4−CD8− NKT cells. We conclude that, unlike conventional naive, memory, or effector T cells, the entire NKT cell population expresses nonlymphoid tissue homing chemokine receptors, yet NKT cell subsets differ considerably from each other by displaying distinct and reciprocal expression patterns of some chemokine receptors. Our results identify chemokine receptors that are potentially important for trafficking of human blood NKT cell subsets and reveal their function (cytokine production capacity)–dependent differential trafficking potentials.
Hematopoietic progenitor kinase 1 supports apoptosis of T lymphocytes
Authors: Schulze-Luehrmann Jan , Santner-Nanan Brigitte , Jha Mithilesh Kumar , Schimpl Anneliese , Avots Andris , Serfling Edgar
Published: October 2002

Hematopoietic progenitor kinase 1 (HPK1) is a member of germinal center kinases that is predominantly expressed in hematopoietic cells and transiently activated by T-cell receptor (TCR) triggering. We show here that HPK1 supports apoptosis of T cells. When HPK1 was overexpressed in murine CD4+ T cells, a substantial increase was observed in spontaneous and TCR/CD3-mediated apoptosis as well as in Fas ligand (FasL) expression. In H2O2-treated EL-4 thymoma cells, which show an increase in reactive oxygen species (ROS) and apoptosis, overexpression of HPK1 enhanced ROS-mediated apoptosis, whereas expression of HPK1 antisense (AS) RNA impaired apoptosis. HPK1 expression also led to a sustained increase in c-Jun N-terminal kinase (JNK) activity, suggesting that JNK activation contributes to the HPK1-mediated apoptosis in H2O2-treated EL-4 cells. Under the same conditions, a rapid cleavage of HPK1 was observed, and overexpression of N- and C-terminal cleavage products in CD4+ T cells resulted in, similar to full-length HPK1, an increase in apoptosis. In agreement with published data, we show that the C-terminal portion of HPK1 suppresses IκBα degradation, thereby inhibiting nuclear factor (NF)–κB activation. These findings suggest that by inhibiting the antiapoptotic action of NF-κB and inducing the proapoptotic activity of JNK, OHPK1 supports apoptosis in T cells.
Activity of STI571 in chronic myelomonocytic leukemia with a platelet-derived growth factor β receptor fusion oncogene
Authors: Magnusson Magnus K. , Meade Kristin E. , Nakamura Ryotaro , Barrett John , Dunbar Cynthia E.
Published: October 2002

Platelet-derived growth factor β receptor (PDGFβR) fusion genes have been shown to be critical transforming oncogenes in a subset of patients with chronic myelomonocytic leukemia (CMML). The sensitivity of dysregulated tyrosine kinase oncogenes to the tyrosine kinase inhibitor STI571 (imatinib mesylate) makes it a potentially attractive treatment option in this subset of patients. We have recently cloned a novel member of the PDGFβR fusion oncogene family, rabaptin-5-PDGFβR. A patient with CMML carrying the rabaptin-5-PDGFβR fusion gene underwent allogeneic stem cell transplantation (SCT) and was monitored closely with a sensitive reverse transcriptase–polymerase chain assay to detect the novel fusion gene transcript. After achieving a molecular remission at 5 months after transplantation, 15 months after SCT the patient showed persistent and progressive evidence of molecular relapse. After demonstrating in vitro that cells transformed with this specific fusion oncogene are efficiently killed by STI571, the patient was started on STI571. The patient responded rapidly and entered molecular remission after 6 weeks of therapy, and he continues to be in remission 6 months later. These results suggest that STI571 may be an effective targeted therapy in patients with CMML related to PDGFβR fusion oncogenes.
Overcoming STI571 resistance with the farnesyl transferase inhibitor SCH66336
Authors: Hoover Russell R. , Mahon Francois-Xavier , Melo Junia V. , Daley George Q.
Published: October 2002

The development of chronic myeloid leukemia (CML) is dependent on the deregulated tyrosine kinase of the oncoprotein BCR-ABL. STI571 (imatinib mesylate), an abl tyrosine kinase inhibitor, has proven remarkably effective for the treatment of CML. However, resistance to STI571 because of enhanced expression or mutation of theBCR-ABL gene has been detected in patients. In the current study we show that the farnesyl transferase inhibitor (FTI) SCH66336 (lonafarnib) inhibits the proliferation of STI571-resistant BCR-ABL–positive cell lines and hematopoietic colony formation from peripheral blood samples of STI571-resistant patients with CML. Moreover, SCH66336 enhances STI571-induced apoptosis in STI571-sensitive cells and, in patients with STI571 resistance from gene amplification, cooperates with STI571 to induce apoptosis. Our data provide a rationale for combination clinical trials of STI571 and SCH66336 in CML patients and suggest that combination therapy may be effective in patients with STI571 resistance.