bluuebunny/crossref_metadata_2025 huggingface dataset:
Local temperature optimum of N2O production rates in tropical rain forest soils of Australia
Authors: Breuer Lutz , Butterbach-Bahl Klaus
Published: September 2005

Laboratory experiments are well-accepted approaches to study the temperature dependency of soil N-turnover processes under defined boundary conditions. However, many of these experiments have several drawbacks: the soil temperature regimes investigated are far wider than the span of soil temperatures observed in the field, the increments of the sampled soil temperatures are wide and may hide interesting details such as non-linear reaction of N-turnover processes, and due to the successive sampling over several days nutrient supply and soil moisture conditions change over time. The first 2 drawbacks are especially important when investigating soil samples from tropical rain forests as these sites are characterised by only small temperature amplitudes. Here we show an approach that allows the study of N-turnover processes at realistic soil temperature regimes observed in the field and small temperature increments within a short period of time. N2O production rates are measured for soil samples from 3 tropical rain forest sites in Queensland, Australia. Kinetics of N2O production follow exponential increases with increasing soil temperatures but are additionally characterised by local temperature optima at 2 of the 3 sites. The temperature response of N2O production rates at these 2 sites can be best described by the use of a combined exponential and optimum temperature function, which improves the coefficient of determination from 1% and 13% to 95% and 99%, respectively. The results further indicate that the microbial processes responsible for N2O production are well adapted to the mean annual temperature conditions of these sites. Successful application of the combined exponential and optimum function to other published results of N-turnover studies support this assumption.
Extractable iron and aluminium predict the P sorption capacity of Thai soils
Authors: Wiriyakitnateekul W. , Suddhiprakarn A. , Kheuruenromne I. , Gilkes R. J.
Published: September 2005

The objective of this study was to determine if dithionite- and oxalate-extractable Fe and Al can be used to predict the P sorption capacity of Thai soils. Forty-five samples from diverse soil types were taken from surface and subsurface horizons of soils on sandstone, shale/limestone, granite, and basalt. The samples were analysed for P sorption, dithionite- and oxalate-extractable Fe and Al (Fed, Feo, Ald, Alo), specific surface area (SSA), and other soil properties. Generally P sorption data for these soils were slightly better fitted by the Langmuir equation than the Freundlich equation. The Langmuir P sorption maximum ranged from 35 to 1111 μg/g with a median value of 370 μg/g soil. Soils developed on basalt had higher values of P sorption maximum (xm) (range 400–1111 μg/g, median 597 μg/g) than soils on other parent materials. Fed concentrations in soils (4–74 g/kg) were much higher than Feo concentrations (0.2–13.8 g/kg) with values of Feo/Fed ranging from 0.01 to 0.28 (median 0.09), indicating that most of the free iron oxides were crystalline. Amounts of Ald and Alo were about equal with median values of 1.6 and 1.0 g/kg, respectively. About 80% of the samples had SSA values <40 m2/g. Both the P sorption maximum and Freundlich k were linearly related to SSA (R2 = 0.77, 0.74), Ald (R2 = 0.78, 0.79), Alo (R2 = 0.64, 0.74), Fed (R2 = 0.48, 0.41), Feo (R2 = 0.43, 0.72), and clay content (R2 = 0.48, 0.36). Stepwise regression indicated that 81% of the variability in P sorption by these soils could be explained by a combination of dithionite and oxalate Fe and Al, however, Ald alone is almost as effective in predicting the P sorption capacity of Thai soils.
Histone acetylation affects expression of cellular patterning genes in the Arabidopsis root epidermis
Authors: Xu Cheng-Ran , Liu Cui , Wang Yi-Lan , Li Lin-Chen , Chen Wen-Qian , Xu Zhi-Hong , Bai Shu-Nong
Published: September 2005

The
Arabidopsis
root has a unique cellular pattern in its single-layered epidermis. Cells residing over the intercellular spaces between underlying cortical cells (H position) differentiate into hair cells, whereas those directly over cortical cells (N position) differentiate into non-hair cells. Recent studies have revealed that this cellular pattern is determined by interactions of six patterning genes
CPC
,
ETC
,
GL2
,
GL3
/
EGL3
,
TTG
, and
WER
, and that the position-dependent expression of the
CPC
,
GL2
, and
WER
genes is essential for their appropriate interactions. However, little is known about how the expressions of the pattern genes are determined. Here we show that trichostatin A (TSA) treatment of germinating
Arabidopsis
seedlings alters the cellular pattern of the root epidermis to induce hair cell development at nonhair positions. The effects of TSA treatment are rapid, reversible, concentration-dependent, and position-independent. TSA inhibition of histone deacetylase activity results in hyperacetylation of the core histones H3 and H4, and alters the expression levels and cell specific expression of the patterning genes
CPC
,
GL2
and
WER
. Analysis of histone deacetylase mutant cellular patterning further verified the participation of histone acetylation in cellular patterning, and revealed that
HDA18
is a key component in the regulatory machinery of the
Arabidopsis
root epidermis. We propose a working model to suggest that histone acetylation may function in mediating a positional cue to direct expression of the patterning genes in the root epidermal cells.
Why highly expressed proteins evolve slowly
Authors: Drummond D. Allan , Bloom Jesse D. , Adami Christoph , Wilke Claus O. , Arnold Frances H.
Published: September 2005

Much recent work has explored molecular and population-genetic constraints on the rate of protein sequence evolution. The best predictor of evolutionary rate is expression level, for reasons that have remained unexplained. Here, we hypothesize that selection to reduce the burden of protein misfolding will favor protein sequences with increased robustness to translational missense errors. Pressure for translational robustness increases with expression level and constrains sequence evolution. Using several sequenced yeast genomes, global expression and protein abundance data, and sets of paralogs traceable to an ancient whole-genome duplication in yeast, we rule out several confounding effects and show that expression level explains roughly half the variation inSaccharomyces cerevisiaeprotein evolutionary rates. We examine causes for expression's dominant role and find that genome-wide tests favor the translational robustness explanation over existing hypotheses that invoke constraints on function or translational efficiency. Our results suggest that proteins evolve at rates largely unrelated to their functions and can explain why highly expressed proteins evolve slowly across the tree of life.
Imaging the nanomolar range of nitric oxide with an amplifier-coupled fluorescent indicator in living cells
Authors: Sato Moritoshi , Hida Naoki , Umezawa Yoshio
Published: September 2005

Nitric oxide (NO) is a small uncharged free radical that is involved in diverse physiological and pathophysiological mechanisms. NO is generated by three isoforms of NO synthase, endothelial, neuronal, and inducible ones. When generated in vascular endothelial cells, NO plays a key role in vascular tone regulation, in particular. Here, we describe an amplifier-coupled fluorescent indicator for NO to visualize physiological nanomolar dynamics of NO in living cells (detection limit of 0.1 nM). This genetically encoded high-sensitive indicator revealed that ≈1 nM of NO, which is enough to relax blood vessels, is generated in vascular endothelial cells even in the absence of shear stress. The nanomolar range of basal endothelial NO thus revealed appears to be fundamental to vascular homeostasis.
Structural basis of hereditary coproporphyria
Authors: Lee Dong-Sun , Flachsová Eva , Bodnárová Michaela , Demeler Borries , Martásek Pavel , Raman C. S.
Published: September 2005

Hereditary coproporphyria is an autosomal dominant disorder resulting from the half-normal activity of coproporphyrinogen oxidase (CPO), a mitochondrial enzyme catalyzing the antepenultimate step in heme biosynthesis. The mechanism by which CPO catalyzes oxidative decarboxylation, in an extraordinary metal- and cofactor-independent manner, is poorly understood. Here, we report the crystal structure of human CPO at 1.58-Å resolution. The structure reveals a previously uncharacterized tertiary topology comprising an unusually flat seven-stranded β-sheet sandwiched by α-helices. In the biologically active dimer (
K
D
= 5 × 10
-7
M), one monomer rotates relative to the second by ≈40° to create an intersubunit interface in close proximity to two independent enzymatic sites. The unexpected finding of citrate at the active site allows us to assign Ser-244, His-258, Asn-260, Arg-262, Asp-282, and Arg-332 as residues mediating substrate recognition and decarboxylation. We favor a mechanism in which oxygen serves as the immediate electron acceptor, and a substrate radical or a carbanion with substantial radical character participates in catalysis. Although several mutations in the CPO gene have been described, the molecular basis for how these alterations diminish enzyme activity is unknown. We show that deletion of residues (392-418) encoded by exon six disrupts dimerization. Conversely, harderoporphyria-causing K404E mutation precludes a type I β-turn from retaining the substrate for the second decarboxylation cycle. Together, these findings resolve several questions regarding CPO catalysis and provide insights into hereditary coproporphyria.
A basis theorem for Π₁⁰ classes of positive measure and jump inversion for random reals
Authors: Downey Rod , Miller Joseph
Published: September 2005

We extend the Shoenfield jump inversion theorem to the members of any

Π
1
0

\Pi ^0_1

class

P

⊆

2
ω

\mathcal {P}\subseteq 2^\omega

with nonzero measure; i.e., for every

Σ
2
0

\Sigma ^0_2

set

S

≥
T

∅
′

S\geq _T\emptyset ’

, there is a

Δ
2
0

\Delta ^0_2

real

A
∈

P

A\in \mathcal {P}

such that

A
′

≡
T

S

A’\equiv _T S

. In particular, we get jump inversion for

Δ
2
0

\Delta ^0_2

1
1

-random reals.
A short proof of the self-improving regularity of quasiregular mappings
Authors: Faraco Daniel , Zhong Xiao
Published: September 2005

We provide a short proof of a theorem, due to Iwaniec and Martin (1993) and Iwaniec (1992), on the self-improving integrability of quasiregular mappings.
Every Reidemeister move is needed for each knot type
Authors: Hagge Tobias
Published: September 2005

We show that every knot type admits a pair of diagrams that cannot be made identical without using Reidemeister

Ω
2

\Omega _2

-moves. The proof is compatible with known results for the other move types, in the sense that every knot type admits a pair of diagrams that cannot be made identical without using all of the move types.
Exponents of class groups of real quadratic function fields (II)
Authors: Chakraborty Kalyan , Mukhopadhyay Anirban
Published: September 2005

Let

g
g

be an even positive integer. We show that there are

≫

q

l

/

g

/

l
2

\gg q^{l/g}/l^2

polynomials

D
∈

F

q

[
t
]

D\in \mathbb F_q[t]

with

deg
⁡
(
D
)
≤
l

\deg (D)\le l

such that the ideal class group of the real quadratic extensions

F

q

(
t
,

D

)

\mathbb F_q(t,\sqrt D)

have an element of order

g
g

.
Cayley graphs of finitely generated groups
Authors: Thomas Simon
Published: September 2005

There does not exist a Borel choice of generators for each finitely generated group which has the property that isomorphic groups are assigned isomorphic Cayley graphs.
A generalized Lucas sequence and permutation binomials
Authors: Akbary Amir , Wang Qiang
Published: September 2005

Let

p
p

be an odd prime and

q
=

p
m

q=p^m

. Let

l
l

be an odd positive integer. Let

p
≡
−
1
 
(

mod

 
l
)

p\equiv -1~(\textrm {mod}~l)

or

p
≡
1
 
(

mod

 
l
)

p\equiv 1~(\textrm {mod}~l)

and

l
∣
m

l\mid m

. By employing the integer sequence
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="a Subscript n Baseline equals sigma-summation Underscript t equals 1 Overscript StartFraction l minus 1 Over 2 EndFraction Endscripts left-parenthesis 2 cosine StartFraction pi left-parenthesis 2 t minus 1 right-parenthesis Over l EndFraction right-parenthesis Superscript n">

a
n

=

∑

t
=
1

l
−
1

2

(
2
cos
⁡

π
(
2
t
−
1
)

l

)

n

\displaystyle {a_n=\sum _{t=1}^{\frac {l-1}{2}} {\left (2\cos {\frac {\pi (2t-1)}{l}}\right )}^n}

, which can be considered as a generalized Lucas sequence, we construct all the permutation binomials

P
(
x
)
=

x
r

+

x
u

P(x)=x^r+x^u

of the finite field

F

q

\mathbb {F}_q

.
Sharply 2-transitive groups with point stabilizer of exponent 3 or 6
Authors: Mayr Peter
Published: September 2005

Using the fact that all groups of exponent

3
3

are nilpotent, we show that every sharply

2
2

-transitive permutation group whose point stabilizer has exponent

3
3

or

6
6

is finite.
Stanley’s theorem on codimension 3 Gorenstein ℎ-vectors
Authors: Zanello Fabrizio
Published: September 2005

In this note we supply an elementary proof of the following well-known theorem of R. Stanley: the

h
h

-vectors of Gorenstein algebras of codimension 3 are SI-sequences, i.e. are symmetric and the first difference of their first half is an

O
O

-sequence.
Stability of the fixed point property in Hilbert spaces
Authors: Mazcuñán-Navarro Eva
Published: September 2005

In this paper we prove that if

X
X

is a Banach space whose Banach-Mazur distance to a Hilbert space is less than

5
+

17

2

\sqrt {\frac {5+\sqrt {17}}{2}}

, then

X
X

has the fixed point property for nonexpansive mappings.
The Oxysterol-binding Protein Homologue ORP1L Interacts with Rab7 and Alters Functional Properties of Late Endocytic Compartments
Authors: Johansson Marie , Lehto Markku , Tanhuanpää Kimmo , Cover Timothy L. , Olkkonen Vesa M.
Published: September 2005

ORP1L is a member of the human oxysterol-binding protein (OSBP) family. ORP1L localizes to late endosomes (LEs)/lysosomes, colocalizing with the GTPases Rab7 and Rab9 and lysosome-associated membrane protein-1. We demonstrate that ORP1L interacts physically with Rab7, preferentially with its GTP-bound form, and provide evidence that ORP1L stabilizes GTP-bound Rab7 on LEs/lysosomes. The Rab7-binding determinant is mapped to the ankyrin repeat (ANK) region of ORP1L. The pleckstrin homology domain (PHD) of ORP1L binds phosphoinositides with low affinity and specificity. ORP1L ANK- and ANK+PHD fragments induce perinuclear clustering of LE/lysosomes. This is dependent on an intact microtubule network and a functional dynein/dynactin motor complex. The dominant inhibitory Rab7 mutant T22N reverses the LE clustering, suggesting that the effect is dependent on active Rab7. Transport of fluorescent dextran to LEs is inhibited by overexpression of ORP1L. Overexpression of ORP1L, and in particular the N-terminal fragments of ORP1L, inhibits vacuolation of LE caused by Helicobacter pylori toxin VacA, a process also involving Rab7. The present study demonstrates that ORP1L binds to Rab7, modifies its functional cycle, and can interfere with LE/lysosome organization and endocytic membrane trafficking. This is the first report of a direct connection between the OSBP-related protein family and the Rab GTPases.
Assembly-dependent Surface Targeting of the Heterodimeric GABAB Receptor Is Controlled by COPI but Not 14-3-3
Authors: Brock Carsten , Boudier Laure , Maurel Damien , Blahos Jaroslav , Pin Jean-Philippe
Published: September 2005

Cell surface expression of transmembrane proteins is strictly regulated. Mutually exclusive interaction with COPI or 14-3-3 proteins has been proposed as a mechanism underlying such trafficking control of various proteins. In particular, 14-3-3 dimers have been proposed to “sense” correctly assembled oligomers, allowing their surface targeting by preventing COPI-mediated intracellular retention. Here we examined whether such a mechanism is involved in the quality control of the heterodimeric G protein-coupled GABAB receptor. Its GB1 subunit, carrying the retention signal RSR, only reaches the cell surface when associated with the GB2 subunit. We show that COPI and 14-3-3 specifically bind to the GB1 RSR sequence and that COPI is involved in its intracellular retention. However, we demonstrate that the interaction with 14-3-3 is not required for proper function of the GABAB receptor quality control. Accordingly, competition between 14-3-3 and COPI cannot be considered as a general trafficking control mechanism. A possible other role for competition between COPI and 14-3-3 binding is discussed.
Dimerization of the ATRIP Protein through the Coiled-Coil Motif and Its Implication to the Maintenance of Stalled Replication Forks
Authors: Itakura Eisuke , Sawada Isao , Matsuura Akira
Published: September 2005

ATR (ATM and Rad3-related), a PI kinase-related kinase (PIKK), has been implicated in the DNA structure checkpoint in mammalian cells. ATR associates with its partner protein ATRIP to form a functional complex in the nucleus. In this study, we investigated the role of the ATRIP coiled-coil domain in ATR-mediated processes. The coiled-coil domain of human ATRIP contributes to self-dimerization in vivo, which is important for the stable translocation of the ATR-ATRIP complex to nuclear foci that are formed after exposure to genotoxic stress. The expression of dimerization-defective ATRIP diminishes the maintenance of replication forks during treatment with replication inhibitors. By contrast, it does not compromise the G2/M checkpoint after IR-induced DNA damage. These results show that there are two critical functions of ATR-ATRIP after the exposure to genotoxic stress: maintenance of the integrity of replication machinery and execution of cell cycle arrest, which are separable and are achieved via distinct mechanisms. The former function may involve the concentrated localization of ATR to damaged sites for which the ATRIP coiled-coil motif is critical.
Evolution of trade patterns in the new EU member states
Authors: Zaghini Andrea
Published: September 2005

The paper analyses the evolution of the trade specialization pattern in the new EU member states. Relying on the empirical approach of the Markov transition matrices it analyses both the changes in the external shape of the distribution of comparative advantages and the intra‐distribution dynamics. The new members show a dynamic trade pattern: they gained comparative advantages relatively fast in sectors in which they were lagging behind at the beginning of the transition, notably in some ‘high tech’ products. In addition, many specialization improvements occurred in those items for which world demand expanded at the fastest rate over the nineties.
Managerial pay and executive turnover in the Czech and Slovak Republics*
Authors: Eriksson Tor
Published: September 2005

Despite the crucial role played by managers in changing the functioning of labour markets in transition economies, research on the determinants of executive pay and CEO turnover in these countries is almost non‐existent. The current paper aims to add to this minuscule literature. For this purpose I make use of a unique dataset containing relevant firm–manager information from the Czech and Slovak Republics in the late nineties. This allows me to examine the influence of individual and in particular firm characteristics, such as, size, ownership type, industry and region, as well as corporate performance on chief executive compensation levels and changes therein and on the extent of executive turnover.
The choice of exchange rate regime: An empirical analysis for transition economies*
Authors: Hagen Jürgen von , Zhou Jizhong
Published: September 2005

We analyze the choice of exchange rate regimes of the 25 transition economies in Europe and the CIS after 1990. The empirical results show that the traditional Optimum Currency Area considerations provide relevant guidance for the regime choices in these countries. Moreover, regime choices are influenced by inflation rates, cumulative inflation differentials, and international reserves sufficiency. That is, macroeconomic stabilization and the ability to commit to exchange rate pegs also play important roles. Large government deficits have ambiguous effects; they increase the likelihood of moving from flexible to intermediate regimes as well as that of moving from fixed to intermediate ones.
How progressive are indirect taxes in Russia?
Authors: Decoster André
Published: September 2005

The interplay of a differentiated indirect tax structure and the variation in expenditure patterns across households leads to a possibly unequal distribution of indirect tax liabilities across the population. This paper uses the ninth round of the RLMS survey to assess the distributional consequences of the two major components of the Russian indirect tax system: VAT and excise taxes. According to the Kakwani index, the global indirect system can be considered to be progressive overall. Decomposition into constituent terms shows that this is due not only to a progressive VAT structure, but also to progressive excise taxes. This result is partly explained by the progressivity of the excise tax on car fuel, but is also sensitive to peculiarities in the data about alcohol consumption.
Real assets, financial assets, liquidity and the lemon problem
Authors: Singh Gurbachan
Published: September 2005

Return obtained by diversification is based on average quality. Similarly, under asymmetric information, the price at which an asset can be sold reflects the average quality of assets. Therefore, 4under some conditions, sale of an asset under asymmetric information is a useful alternative to diversification. This idea is developed with a model that incorporates a liquidity shock. One key result is that investment in real assets is higher under asymmetric information than under symmetric information. The model can explain why the ratio of real assets to financial assets is higher in emerging economies than in developed countries.
Erythrocyte adhesion is modified by alterations in cellular tonicity and volume
Authors: Wandersee Nancy J. , Punzalan Rowena C. , Rettig Michael P. , Kennedy Michael D. , Pajewski Nicholas M. , Sabina Richard L. , Paul Scott J. , Low Philip S. , Hillery Cheryl A.
Published: September 2005

We tested the hypothesis that dehydration‐induced alterations in red blood cell (RBC) membrane organisation or composition contribute to sickle cell adhesion in sickle cell disease (SCD). To examine the role of RBC hydration in adhesion to the subendothelial matrix protein thrombospondin‐1 (TSP), normal and sickle RBCs were incubated in buffers of varying tonicity and tested for adhesion to immobilised TSP under flow conditions. Sickle RBCs exhibited a decrease in TSP binding with increasing cell hydration (P < 0·005), suggesting that cellular dehydration may contribute to TSP adhesion. Consistent with this hypothesis, normal RBCs showed an increase in TSP adhesion with increasing dehydration (P < 0·01). Furthermore, increased TSP adhesion of normal RBCs could also be induced by isotonic dehydration using nystatin‐sucrose buffers. Finally, TSP adhesion of both sickle RBCs and dehydrated normal RBCs was inhibited by the anionic polysaccharides, chondroitin sulphate A and high molecular weight dextran sulphate, but not by competitors of CD47‐, band 3‐, or RBC phosphatidylserine‐mediated adhesion. More importantly, we found increased adhesion of nystatin‐sucrose dehydrated normal mouse RBCs to kidney capillaries following re‐infusion in vivo. In summary, these findings demonstrate that changes in hydration can significantly impact adhesion, causing normal erythrocytes to display adhesive properties similar to those of sickle cells and vice versa.
Limitations of detection of malignancy in pleural effusions using ELISA‐based TRAP assay: comparison with cytological examination
Authors: Lee W.‐Y.
Published: September 2005

Objective:  Telomerase is active in almost all cancers from various organs but is not detectable in most normal cells. Thus, telomerase activity might be a universal and specific marker for diagnosing malignancy. The aim was to evaluate the potential use of the ELISA‐based TRAP assay to detect malignancy in pleural effusion, and to compare it with conventional cytological examination.

Methods:  Using the ELISA‐based TRAP assay, telomerase activity was examined in 94 consecutive pleural effusions submitted for cytological examination.

Results:  According to the results of cytology, the 94 samples were divided into two groups: group I, 79 non‐malignant pleural effusions, including group IA, no association with a malignant tumour, a control group (n = 63), and group IB, associated with a malignant tumour (n = 16); and group II, 15 malignant pleural effusions. Telomerase activity was detected in five of 63 samples in group IA (7.9%), four of 16 samples in group IB (25%), and six of 15 samples in group II (40%). All five false‐positive effusions were from patients with tuberculosis. Comparing group II with group IA, the TRAP assay showed 40% sensitivity, 92.1% specificity, 54.5% positive and 86.6% negative predictive value, and 82.1% accuracy. However, the detection rate of the TRAP assay (88.9%) was higher than that of the cytological examination (66.7%) in lung cancer‐inflicted pleural effusions.

Conclusion:  The ELISA‐based TRAP assay is relatively insensitive; therefore, it is unsuitable as a routine diagnostic tool for pleural effusion. False‐positive telomerase activity due to lymphocytic contamination may weaken its diagnostic value for malignant effusions in a tuberculosis‐endemic area.
Cytoplasmic colloid inclusions in thyroid lesions: a cytomorphological study based on fine needle aspiration
Authors: Das D. K. , Pathan S. K. , Francis I. M. , Sheikh Z. A. , AL‐Juwaiser A. , Shaheen A. , Prabha K. , George J. , Kapila K.
Published: September 2005

Introduction:  Intracytoplasmic lumens (ICL) with or without magenta material and transgressing vessels are features of Hürthle cell neoplasms (HCN). After detection of intracytoplasmic colloid inclusions (CIs) including targetoid (magenta) body‐like structures in the Hürthle cells (HC) in a case of Hashimoto's thyroiditis (HT), we reviewed cases of HT, thyroid neoplasms, hyperplastic nodules (HN) and colloid goitres to determine the frequency of these structures. Further, an attempt was made to find out the significance of CIs.

Methods:  FNA smears of 120 HT, 101 colloid goitres, 11 HN, and 76 neoplastic goitres were examined. The presence of CIs and empty ICL were noted in epithelial cells in these lesions. An attempt was made to find out the difference between HT with and without CIs in respect of various cytomorphologic features. The groups were compared using the Fisher's exact test of probability.

Results:  The CIs were present in 36 (30.0%) of HT, 26 (34.2%) of neoplastic goitres, 3 (27.3%) of HN, and 4 (4.0%) colloid goitres. As compared to colloid goitres, CIs were present in a significant higher number of cases in HN (P = 0.0202), neoplastic goitres (P < 0.0001), and HT (P < 0.0001). Among neoplasms the frequency of CIs in HCN (75.0%) was significantly higher than that of papillary thyroid carcinoma (PTC) (33.3%, P = 0.0466), and follicular neoplasm (14.3%, P = 0.0083). The CIs were more frequent in HC in HT and HCN but in follicular cells (FC) in other lesions. The HT cases with CIs differed significantly from those without CIs in respect of HC and their cellularity, cellularity of reactive lymphoid cells, extracellular colloid and empty ICL.

Conclusion:  Care should be taken not to diagnose HT cases with an excessive Hürthle cell component and CIs, and PTC cases with Hürthlization and CIs, as HCN in FNA smears. Based on review of the literature and our findings, it is suggested that the Hürthle cell metaplasia in HT is a survival response of FC and the presence of CIs in Hürthle cell may represent their limited ability to synthesize colloid.
Effect of intensive training on heart rate variability in prepubertal swimmers
Authors: Vinet A. , Beck L. , Nottin S. , Obert P.
Published: September 2005

Background  In children, there is very limited evidence focusing on the beneficial effect of exercise training on heart rate variability (HRV) during childhood. Despite the fact that more and more children are engaged in intensive training programs, the question arises if such intensive training involves deleterious effects on the cardiac autonomic nervous system during childhood. Thus the aim of the present study was to compare HRV parameters in highly trained swimmer boys and untrained counterparts.

Methods  Twenty prepubertal boys, aged 11–12 years old, took part in the study. The children were divided into 11 highly trained prepubertal swimmers (training sessions of 8–10 h weekly for at least 4 years) and 9 age‐matched active boys. HRV analysis was performed on diurnal recordings in the frequency (short‐term recordings 6 min the most ‘vagal’) and time (long‐term recordings 4 h centred on the 6 min most ‘vagal’) domains.

Results  No significant differences were obtained between groups for all frequency variables whatever the mode of expression (absolute in ms2, relative in Ln or %). All time‐domain components were not significantly different in swimmers and untrained boys.

Conclusions  The results of the present study demonstrate that participating intensively in swimming training does not induce in children changes in HRV indices. Neither time nor domain HRV variables were significantly different between untrained and highly trained prepubertal boys. Thus, intensive training in healthy children does not involve deleterious effects on HRV.
Silent and humming nasal NO measurements in adults aged 18–70 years
Authors: Struben V. M. D. , Wieringa M. H. , Mantingh C. J. , Bruinsma S. M. , De Jongste J. C. , Feenstra L.
Published: September 2005

Background  The concentration of nitric oxide (NO) measured from the nose is much higher than in the lower airways and increases during humming. We assessed nasal NO (nNO) normal values during breath hold and during humming in healthy adults.

Materials and methods  Nasal NO concentrations were measured in healthy adults (ages 18–70). They held their breath for 10 s and thereafter hummed as loud as possible with their mouths closed also for 10 s. During breath hold, air was passively extracted from one nostril with 700 mL min−1. The average NO concentration at the plateau after 7–10 s was recorded and the mean of three consecutive measurements was calculated. During humming, air was extracted with 1200 mL min−1, the peak NO values were recorded.

Results  One hundred healthy adults participated (37 men). The nNO concentrations during breath hold were distributed normally (mean: 455 parts per billion (p.p.b.), SD 147). A random subgroup of 40 out of the 100 subjects (15 men) performed nNO measurement during humming. The median peak NO value was 1019 p.p.b. (SD 561) at the first, and 837 p.p.b. (SD 408) at the second measurement. There was a significant difference between the peak NO values of first and second humming.

Conclusion  We present normal values for nNO in adults, which can be used to assess the value of nNO in respiratory illnesses. The peak nNO values during humming are variable, and their clinical relevance remains to be shown.
Paradox of simultaneous intestinal ischaemia and hyperaemia in inflammatory bowel disease
Authors: Hatoum O. A. , Binion D. G. , Gutterman D. D.
Published: September 2005

This review has focused on evidence regarding intestinal perfusion of inflammatory bowel disease (IBD). Basic investigation has defined an altered microvascular anatomy in the affected IBD bowel, which corresponds with diminished mucosal perfusion in the setting of chronic, long‐standing inflammation. Diminished perfusion is linked to impaired wound healing, and may contribute to the continued refractory mucosal damage, which characterizes IBD. Alterations in vascular anatomy and physiology in IBD suggests additional possible mechanisms by which micro‐vessels may contribute to the initiation and perpetuation of IBD. This begs the following questions: will angiogenesis within the gut lead to sustained inflammation, does the growing vasculature generate factors that transform the surrounding tissue and does angiogenesis generate vascular anastomosis within the gut, with shunting of blood away from the mucosal surface, impairment of metabolism and potentiation of gut damage? Further studies are required to define the mechanisms that underlie the vascular dysfunction and its role in pathophysiology of IBD.
Host‐specific aphid population responses to elevated CO2 and increased N availability
Authors: Sudderth Erika A. , Stinson Kristina A. , Bazzaz F. A.
Published: September 2005

Sap‐feeding insects such as aphids are the only insect herbivores that show positive responses to elevated CO2. Recent models predict that increased nitrogen will increase aphid population size under elevated CO2, but few experiments have tested this idea empirically. To determine whether soil nitrogen (N) availability modifies aphid responses to elevated CO2, we tested the performance of Macrosiphum euphorbiae feeding on two host plants; a C3 plant (Solanum dulcamara), and a C4 plant (Amaranthus viridis). We expected aphid population size to increase on plants in elevated CO2, with the degree of increase depending on the N availability.

We found a significant CO2× N interaction for the response of population size for M. euphorbiae feeding on S. dulcamara: aphids feeding on plants grown in ambient CO2, low N conditions increased in response to either high N availability or elevated CO2. No population size responses were observed for aphids infesting A. viridis. Elevated CO2 increased plant biomass, specific leaf weight, and C : N ratios of the C3 plant, S. dulcamara but did not affect the C4 plant, A. viridis. Increased N fertilization significantly increased plant biomass, leaf area, and the weight : height ratio in both experiments. Elevated CO2 decreased leaf N in S. dulcamara and had no effect on A. viridis, while higher N availability increased leaf N in A. viridis and had no effect in S. dulcamara. Aphid infestation only affected the weight : height ratio of S. dulcamara.

We only observed an increase in aphid population size in response to elevated CO2 or increased N availability for aphids feeding on S. dulcamara grown under low N conditions. There appears to be a maximum population growth rate that M. euphorbiae aphids can attain, and we suggest that this response is because of intrinsic limits on development time and fecundity.
Carbon pools in a boreal mixedwood logging chronosequence
Authors: Martin Jennifer L. , Gower Stith T. , Plaut Jennifer , Holmes Bruce
Published: September 2005

Mixedwood forests are an ecologically and economically important forest type in central Canada, but the ecology of these forests is not as well studied as that of single‐species dominated stands in the boreal forest. Northern boreal mixedwood forests have only recently been harvested and the effects of harvesting on carbon content in these stands are unknown. We quantified the carbon content and aboveground net primary production (NPP) for four different‐aged mixedwood boreal forest stands in northern Manitoba, Canada. The stands included 11‐, 18‐, and 30‐year‐old stands that originated from harvesting and a 65‐year‐old fire‐originated stand that typifies the origin of all northern boreal mixed‐wood forests that are coming under management. Trees included black spruce (Picea mariana (Mill.) B.S.P.), jack pine (Pinus banksiana Lamb.), balsam poplar (Populus balsamifera L.), and quaking aspen (Populus tremuloides Michx.). Overstory biomass was estimated using species‐specific allometric models that generally explained greater than 95% of the observed variation in biomass. Carbon content of the overstory vegetation was greatest in the 65‐year‐old stand and was 74% larger than the 11‐year‐old stand and showed a positive relationship with stand age (F1, 2=122.62, P=0.0081 R2=0.99). The slope of mineral soil carbon did not differ significantly among stands (F1, 2=0.39, P=0.5956, R2=0.16). Coarse woody debris carbon content followed a U‐shaped pattern among stands. Aboveground NPP differed by 24% between the youngest and oldest stand. Mean annual carbon accumulation and aboveground NPP rates of the mixedwood forests were on average two times greater than nearby relatively pure stands studied during the BOREAS (BOReal Ecosystem Atmospheric Study) project. The trends in the results, along with other field studies, suggest that harvesting does not significantly affect the total soil carbon content. The results of this study suggest that scientists should be cautious about extrapolating results from BOREAS stands to a broader region until more data on other forest types and regions are available.
Estimation of the whole‐plant CO2compensation point of tobacco (Nicotiana tabacumL.)
Authors: Campbell Catherine D. , Sage Rowan F. , Kocacinar Ferit , Way Danielle A.
Published: September 2005

The whole‐plant CO2compensation point (Γplant) is the minimum atmospheric CO2level required for sustained growth. The minimum CO2requirement for growth is critical to understanding biosphere feedbacks on the carbon cycle during low CO2episodes; however, actual values of Γplantremain difficult to calculate. Here, we have estimated Γplantin tobacco by measuring the relative leaf expansion rate at several low levels of atmospheric CO2, and then extrapolating the leaf growth vs. CO2response to estimate CO2levels where no growth occurs. Plants were grown under three temperature treatments, 19/15, 25/20 and 30/25°C day/night, and at CO2levels of 100, 150, 190 and 270 μmol CO2 mol−1 air. Biomass declined with growth CO2such that Γplantwas estimated to be approximately 65 μmol mol−1for plants grown at 19/15 and 30/25°C. In the first 19 days after germination, plants grown at 100 μmol mol−1had low growth rates, such that most remained as tiny seedlings (canopy size <1 cm2). Most seedlings grown at 150 μmol mol−1and 30/25°C also failed to grow beyond the small seedling size by day 19. Plants in all other treatments grew beyond the small seedling size within 3 weeks of planting. Given sufficient time (16 weeks after planting) plants at 100 μmol mol−1eventually reached a robust size and produced an abundance of viable seed. Photosynthetic acclimation did not increase Rubisco content at low CO2. Instead, Rubisco levels were unchanged except at the 100 and 150 μmol mol−1where they declined. Chlorophyll content and leaf weight per area declined in the same proportion as Rubisco, indicating that leaves became less expensive to produce. From these results, we conclude that the effects of very low CO2are most severe during seedling establishment, in large part because CO2deficiency slows the emergence and expansion of new leaves. Once sufficient leaf area is produced, plants enter the exponential growth phase and acquire sufficient carbon to complete their life cycle, even under warm conditions (30/25°C) and CO2levels as low as 100 μmol mol−1.
The effect of statin therapy on plasma high‐density lipoprotein cholesterol levels is modified by paraoxonase‐1 in patients with familial hypercholesterolaemia
Authors: VAN HIMBERGEN T. M. , VAN TITS L. J. H. , VOORBIJ H. A. M. , DE GRAAF J. , STALENHOEF A. F. H. , ROEST M.
Published: September 2005

Objectives.  Statins reduce low‐density lipoprotein cholesterol (LDL‐C) and can raise high‐density lipoprotein cholesterol (HDL‐C). HDL‐bound paraoxonase‐1 (PON1) is associated with variations in plasma HDL‐C, and may, therefore, contribute to changes of HDL‐C during statin therapy.

Design.  The effects of baseline PON1 status to HDL‐C changes because of statin therapy were investigated. PON1 status was determined with (i) PON1 −107C>T and 192Q>R genotype, (ii) PON1 levels and (iii) PON1 paraoxonase, diazoxonase and arylesterase activity.

Setting.  Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.

Subjects.  A total of 134 familial hypercholesterolaemia (FH) patients undergoing atorvastatin or simvastatin therapy.

Results.  PON1 levels and activities significantly modified the HDL‐C increment (P = 0.002 for PON1 levels and arylesterase activity and P =0.001 for diazoxonase activity). The effects were even more evident amongst subgroup classifications based on PON1 status and baseline HDL‐C concentrations: the HDL‐C increment was more pronounced in subgroups of −107CT/TT or 192QR/RR genotype combined with low baseline HDL‐C (+13.9%, P < 0.001, respectively +15.4%, P < 0.001). In contrast, the −107CC or 192QQ genotype in combination with high baseline HDL‐C, did not show a significant increase of HDL‐C.

Conclusions.  PON1 status in conjunction with baseline HDL‐C levels predicts HDL‐C increment during statin therapy in FH patients.
Islet‐1 Expression and its Colocalisation with Luteinising Hormone, Thyroid‐Stimulating Hormone and Oestrogen Receptor Alpha in the Developing Pituitary Gland of the Sheep Foetus
Authors: Liu J. , Liu Z. , Yi S. , Cui S.
Published: September 2005

Islet‐1 has been reported to be involved in pituitary development in the early stages of mouse embryogenesis. Oestrogen receptor (ER) and its expression may be involved in regulating pituitary development and its hormone‐secreting function. Islet‐1 expression and its correlations to ER in the developing pituitary gland are unknown. We therefore determined the pituitary cell specific expression of Islet‐1 and its colocalisation with ER alpha (ERα) in sheep foetus by immunohistochemistry. The results demonstrated that Islet‐1‐immunoreacitive (ir) cells were distributed throughout the pituitary gland from day 60 of gestation until birth. The Islet‐1‐ir cell number was significant higher at day 90 and 120 of gestation compared to that at day 60 and at birth. All of the ERα‐ir cells were colocalised with Islet‐1 at day 60 of gestation, although a few ERα‐ir cells were negative for Islet‐1 in the later stage of gestation. The dominant cell type expressing Islet‐1 is the gonadotroph, although small proportions of thyrotrophs and lactotrophs also express Islet‐1. The proportion of luteinising hormone‐ir gonadotrophs possessing Islet‐1 kept rising from day 60 to day 120 of gestation and persisted until birth. The proportion of thyroid‐stimulating hormone‐ir cells expressing Islet‐1 was at a high level from day 60–120 of the gestation and significantly declined at birth. The percentage of prolactin (PRL)‐ir cells expressing Islet‐1 was about 20% at day 60 of gestation. Very few PRL‐ir cells contained Islet‐1 in later stages of gestation. These data suggest that the development and functional establishment of pituitary gonadotrophs, thyrotrophs and lactotrophs might be regulated by the expressions of Islet‐1 and ERα and by their interactions, although any mechanisms need to be elucidated further.
Genetic similarity of hepatitis C virus and fibrosis progression in chronic and recurrent infection after liver transplantation
Authors: López‐Labrador F.‐X. , Bracho M. A. , Berenguer M. , Coscollà M. , Rayón J. M. , Prieto M. , Carrasco D. , Gómez M. D. , Moya A. , González‐Candelas F.
Published: September 2005

Summary.  The effect of hepatitis C virus (HCV) genetic heterogeneity on clinical features of post‐transplantation hepatitis C is controversial. Different regions of the HCV genome have been associated with apoptosis, fibrosis, and other pathways leading to liver damage in chronic HCV infection. Besides, differences in immunodominant regions, such as NS3, may influence HCV‐specific immune responses and disease outcome. In the liver transplant setting, a recent study has reported a positive association between HCV‐1b Core region genetic relatedness 5‐year post‐transplantation and histological severity of recurrent hepatitis C. We have compared nucleotide sequences of HCV Core, NS3 and NS5b regions in HCV‐1b‐infected patients 3 years post‐transplantation (n = 22). A cohort of nontransplanted patients (n = 22) was used as control of natural chronic HCV‐1b infection. Histological evaluation was used to define the rate of fibrosis progression. Molecular variance analysis did not show significant differences in HCV sequences between transplanted and nontransplanted patients, or between those with fast or slow fibrosis progression. The same results were obtained when analysing phylogenetic trees for Core, NS3 and NS5b regions. A more appropriate clustering method (using minimum spanning networks) revealed a significant positive relationship between HCV genetic similarity in Core (r = 0.550, P < 0.01) and NS5b regions (r = 0.847, P < 0.01) and the yearly rate of fibrosis progression in nontransplanted patients which, in contrast, was not observed in transplanted patients. Our results indicate that some strains of HCV‐1b might be more pathogenic in the natural course of chronic infection by this virus subtype. In the liver transplant setting, when the immune response is severely compromised, other mechanisms are probably more important in determining hepatitis C progression.
Detailed analysis of the E2–IgM complex in hepatitis C‐related type II mixed cryoglobulinaemia
Authors: Ferri S. , Dal Pero F. , Bortoletto G. , Bianchi F. B. , Lenzi M. , Alberti A. , Gerotto M.
Published: September 2005

Summary.  Hepatitis C virus (HCV) plays a major role in the induction of type II mixed cryoglobulinaemia (MCII). The role of HCV proteins and virus–host interaction in the pathogenesis of MC remains to be defined. To address this issue, we have characterized, in detail, the monoclonal IgM and the viral component of circulating immune complexes in eight patients with HCV‐associated MCII. The proportion of HCV‐RNA compartmentalized in the cryoprecipitate (CP) varied greatly (10–80% of total HCV‐RNA). The complementary determining region (CDR)3 sequences of monoclonal immunoglobulin M (IgM) VH and VK genes were highly homologous to rheumatoid factor and to antibodies against HCV‐E2. Furthermore, the CDR3 sequences in some of our MCII patients were highly similar to those described in HCV‐positive patients with non‐Hodgkin's lymphoma (NHL). From these results, it appears that, as in the case of NHL, the IgM‐rheumatoid factor (RF) production in MCII patients is antigen driven, namely by E2. However, the limited number of mutations in VH and VK genes with respect to the germline and their distribution showed that the B‐cell response in these cases was prevented from undergoing affinity maturation. Furthermore, in patients with monoclonal IgM and definite compartmentalization of HCV in either CP or supernatant, a highly homogeneous E2‐hypervariable region (HVR)1 sequence distribution was found (90–100% identical clones), a feature of the quasispecies frequently associated with an impaired humoral immune response to HCV. These findings suggest that in patients with HCV‐associated MCII, maturation of monoclonal B lymphocytes may be blocked in a primitive stage preventing serious damaging effects because of the auto‐reactivity of their secreted immunoglobulins.