bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of magnetic activity on the dynamics of equatorial F region irregularities
Authors: Bhattacharyya A. , Basu S. , Groves K. M. , Valladares C. E. , Sheehan R.
Published: October 2003

Two different aspects of the effect of magnetic activity on the dynamics of equatorial spread F (ESF) irregularities are studied here using spaced receiver scintillation observations. The first one deals with the question of how magnetic activity affects the generation of ESF irregularities. For this, a parameter designated the “random velocity,” which is a measure of random changes in the irregularity drift velocity, is evaluated from the data. In past studies, this parameter has been found to have large values in the early phase of evolution of ESF irregularities during the postsunset period, with a steep decline to a low value by 22 LT. This behavior is attributed to the decline in the height of the F region. Therefore, a sudden increase in the “random velocity” in the postmidnight period is attributed to an increase in the height of the F region due to the ionospheric zonal electric field turning from westward to eastward due to the effect of magnetic activity, which may also generate fresh irregularities that produce the observed scintillations. This idea has been used to suggest that for two of the magnetically active days considered in the present study the irregularities may be freshly generated in the postmidnight period. The second aspect is the identification of geomagnetically disturbed plasma drifts, which is generally possible only after 22 LT, when the estimated irregularity drift velocities are close to that of the background plasma. The pattern of the estimated drift after 22 LT (3 UT) is found to be well defined for magnetically quiet days with scintillations during a period of a month. This allows the identification of a superimposed westward perturbation in the drift, produced by a disturbance dynamo due to magnetic activity, for all the three events studied here. On 19 February and 1 March 1999, the eastward drift velocities show an identical decrease of about 50 m/s from the undisturbed drift at 0440 UT. On 1 March, the decay phase of the storm sets in later, and the eastward velocity continues to decrease until 0530 UT, turning westward with a maximum decrease of about 80 m/s from the undisturbed drift. On 22 October 1999, which was more disturbed than these two days, the westward perturbation was larger, causing the drift velocity to turn westward around 5 UT and a decrease of nearly 150 m/s from the quiet time drift at 8 UT. The results are in broad agreement with some of the recent empirical models of the evolution, with storm time, of equatorial disturbance dynamo electric fields.
Absent anisotropy: The paradox of the Southern Alps orogen
Authors: Pulford Anna , Savage Martha , Stern Tim
Published: October 2003

A high resolution active source dataset recorded across the Southern Alps of New Zealand displays unusually strong S‐wave phases, which show minimal shear wave splitting. A suite of methods was used to analyse the data to minimize the uncertainty in the anisotropy measurements. We use the Silver and Chan [1991] method, cross correlation of stacked data, and deconvolution in combination with the other methods. The results were consistent at each station, but differed between stations. Fault‐parallel fast directions with delay times of 0–0.08 s were calculated from the most impulsive S‐wave arrivals. The crustal rocks from the Southern Alps are strongly anisotropic in the laboratory, contrasting with results shown here. The minimal delay times suggest that the shear waves are affected by multiple phases of deformation in the crust.
Crystal orientation fabrics within the Antarctic ice sheet revealed by a multipolarization plane and dual‐frequency radar survey
Authors: Matsuoka Kenichi , Furukawa Teruo , Fujita Shuji , Maeno Hideo , Uratsuka Seiho , Naruse Renji , Watanabe Okitsugu
Published: October 2003

To investigate the viscosity structure of ice sheets induced by crystal orientation fabric (COF), we carried out a multipolarization plane and dual‐frequency radar survey in East Antarctica. Radar surveys were done along a 670‐km‐long flow line from Dome Fuji toward the coast and two transverse lines of 300‐km and 20‐km length, respectively. The radar echoes were highly dependent on the polarization plane for ice depths between about 40 and 60% of the ice thickness in the lower reaches of the convergent ice flow sector approaching the outlet glacier. When the polarization was perpendicular to the ice flow, echoes were about 10 dB stronger than when the polarization was parallel to the ice flow. This feature was not clear in the upper part of this convergent flow sector. Farther inland, where ice flow is divergent or parallel, the radar echo varied by several decibels because of changes of the radar polarization and had maxima in two orientations. Dual‐frequency data showed that the cause of the reflections was changes in COF. Multipolarization data identified anisotropic reflectivities and birefringence as causes of the anisotropic radar echoes in the lower and upper reaches, respectively. With the aid of ice‐core‐based studies on COF, we show that ice is composed of stacked layers of single‐pole and vertical girdle fabrics in the lower reaches. In contrast, we argue that changes of single‐pole clustering cause isotropic reflectivities in the upper reaches. We also discuss on the development of COF along ice flow and its implication to ice sheet dynamics.
Longitudinal evaluation of GCF IFN‐γ levels and periodontal status in HIV+ patients
Authors: Alpagot T. , Font K. , Lee A.
Published: October 2003

Background/Aim: Loss of periodontal support and related tooth loss is a common finding among HIV+ patients. The etiology of this destruction may be an increase in the levels of pro‐inflammatory cytokines and subsequent increase in periodontal disease activity. The purpose of this study was to investigate the associations between gingival crevicular fluid interferon gamma (GCF IFN‐γ) and clinical measures of periodontal disease in HIV+ individuals. We monitored GCF IFN‐γ and periodontal status of selected sites in 33 HIV+ subjects over a 6‐month period.

Method: Clinical measurements including gingival index, plaque index, bleeding on probing, probing depth, attachment loss (AL), and GCF samples were taken from four lower incisors and the upper right posterior sextant of each patient at baseline and 6‐month visits by means of sterile paper strips. GCF levels of IFN‐γ were determined by sandwich ELISA assays. A progressing site was defined as a site that had 2 mm or more AL during the 6‐month study period.

Results: Twenty‐five of the 264 examination sites showed 2 mm or more clinical AL during the 6‐month study period. Significantly higher GCF levels of IFN‐γ were found at progressing sites than in nonprogressing sites (p<0.001). GCF levels of IFN‐γ were highly correlated with clinical measurements taken at baseline and 6‐month visits (0.001<p<0.01).

Conclusion: These data indicate that sites with high GCF levels of IFN‐γ are at significantly greater risk for progression of periodontitis in HIV+ patients.
Self‐reported gingival conditions and self‐care in the oral health of Danish women during pregnancy
Authors: Christensen Lisa Bøge , Jeppe‐Jensen Dorte , Petersen Poul Erik
Published: October 2003

Objectives: The purpose of the present study was to describe the self‐assessment of gingival health conditions in pregnant women, their oral hygiene behaviour and dental visiting habits, and to analyse self‐care practices of pregnant women in relation to perceived gingival problems.

Material and Methods: The study group comprised 1935 pregnant women living in two areas of Denmark consecutively recruited from August 1998 to March 1999. The survey data were based on telephone interviews. Questions in the interview concerned general health, lifestyles, socioeconomic conditions, gingival conditions, oral hygiene and utilisation of dental health services.

Results: One‐third of the study population perceived signs of gingival inflammation; 5% of the pregnant women assessed their gingiva as poor, while 95% reported good or “normal” gingival condition. Ninety six per cent brushed their teeth at least twice a day and nine out of 10 were regular users of the dental‐care system. Twenty‐seven per cent of those women with pregnancy gingivitis responded to the symptoms by, for example, seeing a dentist or intensifying the oral hygiene habits.

Conclusion: Despite a high level of self‐efficacy among the pregnant women as for oral health and oral health care combined with a high level of oral hygiene and dental visiting habits, there seems to be a substantial need for increased awareness of gingival oral health.
Skin biophysical properties of a population living in Valais, Switzerland
Authors: Wendling Pierre‐André , Dell'Acqua Giorgio
Published: October 2003

Background/purpose: Switzerland has one of the highest rates of skin diseases and particularly skin cancer, in Europe. Skin elastosis, roughness and atopy are also frequent. High UV exposure and prevalence of light skin individuals could be the cause. Valais, in Southern Switzerland, is a mountain region with elevated sun irradiation and low air humidity, an ideal location to study the effect of the environment and life style on skin biophysical characteristics. The purpose of the study was to measure skin biophysical parameters non‐invasively on healthy subjects living in Valais, and to correlate the measures with their life style.

Methods: One hundred and ten women were examined between October 2001 and February 2002. Measures of skin hydration, sebum content, pH and visco‐elasticity were taken in a closed environment with constant temperature and controlled air humidity, utilizing commercially available non‐invasive devices. Subjects were interviewed using a questionnaire and data on personal traits and life style were collected. Correlations between subject's skin parameters and life style were statistically examined.

Results: On average we observed low values of skin capacitance that identify subjects with dry skin. Measures of skin visco‐elasticity ratios were also particularly low, while skin pH and sebum content were in the normal range. Age was correlated with a decrease of skin elasticity and sebum content, but there was no correlation with hydration or pH.

Conclusions: We confirm, as reported in other studies, the effect of age on skin elasticity and sebum content and we identify, for the first time, a region with a population characterized by particularly low levels of skin hydration and skin visco‐elasticity. Although people examined were free of skin diseases, we believe that protection from the sun and treatment of skin with hydrating products need to be emphasized as a prevention strategy, in regions such as Valais, with high sun irradiation and low humidity.
Basal electrical impedance in relation to sodium lauryl sulphate‐induced skin reactions – a comparison of patients with eczema and healthy controls
Authors: Kuzmina Natalia , Hagströmer Lena , Nyrén Miruna , Emtestam Lennart
Published: October 2003

Background: Identification of subjects at risk for contact dermatitis by screening tests is desirable in order to adjust the preventive measures to individual skin susceptibility. The present study aimed to examine the effects of basic physiological features, such as baseline electrical imped‐ance (IMP) and transepidermal water loss (TEWL), on reactivity to sodium lauryl sulphate (SLS).

Methods: On the basis of two previous studies, we re‐evaluated the experimental irritant skin reactions (50 μL of 2% SLS in large Finn Chambers for 24 h) on the volar forearms of 29 patients with eczema and 19 healthy controls.

Results: We found definite differences in the baseline values of IMP, between the patients and the controls. Moreover, patients with eczema showed higher TEWL and lower MIX values on day 3 after exposure to SLS, which may indicate differences in SLS reactivity. After the study, the biophysical parameters of the eczema patients did not return to baseline, which suggests that their skin heals more slowly than that of normal subjects.

Conclusions: Our findings indicate that the IMP technique may help to ‘detect’ chemically vulnerable skin. However, more studies are needed to determine the value of the basal electrical impedance parameters in assessing the risk of developing irritant contact dermatitis.
Mechanism of horseradish peroxidase inactivation by benzhydrazide: a critical evaluation of arylhydrazides as peroxidase inhibitors
Authors: AITKEN Susan M. , OUELLET Marc , PERCIVAL M. David , ENGLISH Ann M.
Published: October 2003

Many compounds are oxidized by haem enzymes, such as peroxidases and cytochromes P450, to highly reactive intermediates that function as enzyme inactivators. To evaluate the potential of arylhydrazides as selective metabolically activated peroxidase inhibitors, the mechanism of HRPC (horseradish peroxidase isoenzyme C) inhibition by BZH (benzhydrazide) was investigated in detail. No oxygen consumption was detected in BZH solutions at pH 7.0–12.0, but addition of HRPC resulted in significant O2 uptake above pH 8.0, indicating that the enzyme catalyses BZH oxidation. Addition of H2O2 to HRPC plus BZH activates the latter as an inhibitor. This involves the three-electron oxidation of BZH in one-electron steps by the peroxidase catalytic intermediates, Compounds I and II, to produce a benzoyl radical that covalently alters the active site and inhibits peroxidase activity. Alternatively, the benzoyl radical could be produced by di-imide (NH=NH) elimination from the BZH radical. Production of Compound III (oxyperoxidase) followed by p-670 (m/z=583, biliverdin-like derivative) was observed for HRPC incubated with excess H2O2, and the addition of BZH resulted in an increase in the rate of p-670 production. BZH is an inefficient inhibitor of HRPC with a KI of 80 μM, an apparent inactivation rate constant (kinact) of 0.035 min−1, and an IC50 of 1.0 mM. This prompted the investigation of HRPC inactivation by a series of related arylhydrazides with known binding affinities for HRPC. The hydrazide with the highest affinity (2-naphthoichydrazide; Kd=5.2 μM) was also found to be the most effective inhibitor with KI, kinact and IC50 values of 14 μM, 0.14 min−1 and 35 μM, respectively.
Characterization of Amm VIII from Androctonus mauretanicus mauretanicus: a new scorpion toxin that discriminates between neuronal and skeletal sodium channels
Authors: ALAMI Meriem , VACHER Hélène , BOSMANS Frank , DEVAUX Christiane , ROSSO Jean-Pierre , BOUGIS Pierre E. , TYTGAT Jan , DARBON Hervé , MARTIN-EAUCLAIRE Marie-France
Published: October 2003

The venom of the scorpion Androctonus mauretanicus mauretanicus was screened by use of a specific serum directed against AaH II, the scorpion α-toxin of reference, with the aim of identifying new analogues. This led to the isolation of Amm VIII (7382.57 Da), which gave a highly positive response in ELISA, but was totally devoid of toxicity when injected subcutaneously into mice. In voltage-clamp experiments with rat brain type II Na+ channel rNav1.2 or rat skeletal muscle Na+ channel rNav1.4, expressed in Xenopus oocytes, the EC50 values of the toxin-induced slowing of inactivation were: 29±5 and 416±14 nM respectively for AmmVIII and 2.6±0.3 nM and 2.2±0.2 nM, respectively, for AaH II interactions. Accordingly, Amm VIII clearly discriminates neuronal versus muscular Na+ channel. The Amm VIII cDNA was amplified from a venom gland cDNA library and its oligonucleotide sequence determined. It shows 87% sequence homology with AaH II, but carries an unusual extension at its C-terminal end, consisting of an additional Asp due to a point mutation in the cDNA penultimate codon. We hypothesized that this extra amino acid residue could induce steric hindrance and dramatically reduce recognition of the target by Amm VIII. We constructed a model of Amm VIII based on the X-ray structure of AaH II to clarify this point. Molecular modelling showed that this C-terminal extension does not lead to an overall conformational change in Amm VIII, but drastically modifies the charge repartition and, consequently, the electrostatic dipole moment of the molecule. At last, liquid-phase radioimmunassays with poly- and monoclonal anti-(AaH II) antibodies showed the loss of conformational epitopes between AaH II and Amm VIII.
Variation of the axial haem ligands and haem-binding motif as a probe of the Escherichia coli c-type cytochrome maturation (Ccm) system
Authors: ALLEN James W. A. , FERGUSON Stuart J.
Published: October 2003

Cytochromes c are typically characterized by the covalent attachment of haem to polypeptide through two thioether bonds with the cysteine residues of a Cys-Xaa-Xaa-Cys-His peptide motif. In many Gram-negative bacteria, the haem is attached to the polypeptide by the periplasmically functioning cytochrome c maturation (Ccm) proteins. Exceptionally, Hydrogenobacter thermophilus cytochrome c552 can be expressed as a stable holocytochrome both in the cytoplasm of Escherichia coli in an apparently uncatalysed reaction and also in the periplasm in a Ccm-mediated reaction. In the present study we show that a Met60→Ala variant of c552, which does not have the usual distal methionine ligand to the haem iron of the mature cytochrome, can be made in the periplasm by the Ccm system. However, no holocytochrome could be detected when this variant was expressed cytoplasmically. These data highlight differences between the two modes of cytochrome c assembly. In addition, we report investigations of haem attachment to cytochromes altered to have the special Cys-Trp-Ser-Cys-Lys haem-binding motif, and Cys-Trp-Ser-Cys-His and Cys-Trp-Ala-Cys-His analogues, of the active-site haem of nitrite reductase NrfA.
Hyperthyroidism increases the uncoupled ATPase activity and heat production by the sarcoplasmic reticulum Ca2+-ATPase
Authors: ARRUDA Ana Paula , da-SILVA Wagner S. , CARVALHO Denise P. , de MEIS Leopoldo
Published: October 2003

The sarcoplasmic reticulum Ca2+-ATPase is able to modulate the distribution of energy released during ATP hydrolysis, so that a portion of energy is used for Ca2+ transport (coupled ATPase activity) and a portion is converted into heat (uncoupled ATPase activity). In this report it is shown that T4 administration to rabbits promotes an increase in the rates of both the uncoupled ATPase activity and heat production in sarcoplasmic reticulum vesicles, and that the degree of activation varies depending on the muscle type used. In white muscles hyperthyroidism promotes a 0.8-fold increase of the uncoupled ATPase activity and in red muscle a 4-fold increase. The yield of vesicles from hyperthyroid muscles is 3–4-fold larger than that obtained from normal muscles; thus the rate of heat production by the Ca2+-ATPase expressed in terms of g of muscle in hyperthyroidism is increased by a factor of 3.6 in white muscles and 12.0 in red muscles. The data presented suggest that the Ca2+-ATPase uncoupled activity may represent one of the heat sources that contributes to the enhanced thermogenesis noted in hyperthyroidism.
Enhancement of repopulation haemopoiesis by heterozygous connexin 43 stem cells seeded on wild-type connexin 43 stroma
Authors: ROSENDAAL Martin , STONE Mervyn
Published: October 2003

The present paper analyses the results of competitive blood-cell repopulation experiments in which Cx43-WT (connexin 43 wild-type) host mice, whose own HSCs (haemopoietic stem cells) were deleted, were grafted with fetal liver cells: 50% Gpi-1a (glucose phosphate isomerase-1a)/Cx43-WT cells competing with 50% Gpi-1b/Cx43-WT, 50% Gpi-1b/Cx43-HZ (heterozygous) or 50% Gpi-1b/Cx43-KO (knock-out) cells. The percentages of platelets, granulocytes, red cells, B-cells and T-cells containing Gpi-1b in blood samples obtained from 22 to 186 days after grafting, and the percentages of high-proliferation-potential colony-forming cells containing Gpi-1b at 255 days after grafting, were measured. The results show that, if we wait 4 months so that we measure the percentages of Gpi-1b end-cells formed by initially resting stem cells in the graft, values in HZ mice are greater than those in WT and KO mice by 10% or more. We propose a bipolar influence model for blood formation by grafted HSCs to explain this difference and other features of the data. Influence A is a direct one: for individual HSCs, the combined effect on HSC niching and HSC proliferation of Cx43 is superior to that of the KO allele. Influence B is a demographic one: HZ foundation mice compensate by having more HSCs than WT mice. The net outcome of influences A and B is that HZ is the winner.
Expression of MHC Class II, CD70, CD80, CD86 and pro‐inflammatory cytokines is differentially regulated in oral epithelial cells following bacterial challenge
Authors: Han D. C. , Huang G. T‐J. , Lin L. M. , Warner N. A. , Gim J. S. , Jewett A.
Published: October 2003

Oral epithelium may play a regulatory role in local immune responses when interacting with bacteria. The present study was undertaken to investigate the effects of selected bacterial pathogens found in periodontal and endodontic infections on oral epithelial cells. Expression of cell surface molecules (major histocompatibility complex (MHC) Class II, CD54, CD70, CD80 and CD86) and secretion of inflammatory cytokines (interleukin (IL)‐1β, IL‐6, and tumor necrosis factor (TNF)‐α) in response to selected bacterial challenge were examined on an immortalized oral epithelial cell line, HOK‐18A and a skin epithelial cell line, HaCaT. Actinomyces viscosus, Actinomyces israelii, Fusobacterium nucleatum lipopolysaccharide (LPS) or primary human periradicular exudate from a granuloma were co‐cultured with epithelial cells for 4 or 24 h. Subsequently, cell surface expression of MHC Class II, CD54, CD70, CD80 and CD86, along with pro‐inflammatory cytokine levels were determined using flow cytometry, ELISA and RT‐PCR. Results indicated that the selected oral bacteria have greater effects on oral versus skin epithelial cells. F. nucleatum increased MHC Class II and CD54 (ICAM‐1) cell surface expression on HOK‐18A and HaCaT cells. A. israelii also had enhancing effects on the expression of CD54 and MHC Class II. A. israelii and LPS induced a 2.8‐fold (P < 0.001) and 4.4‐fold (P < 0.005) TNF‐α secretion, respectively, while F. nucleatum and LPS induced a 10‐fold (P < 0.0004) and 6‐fold (P < 0.01) IL‐1β secretion, respectively by HOK‐18A. Interestingly, CD70, CD80, and CD86 were generally decreased upon bacteria and LPS challenge on HOK‐18A. The effects of increased MHC Class II and decreased CD70 were also evident with challenge of human periradicular exudate on HOK‐18A. The implications of the study are unique in that oral epithelial cells may play both activating and inhibitory roles in the host immune response towards infection by oral bacteria. We introduce a concept of ‘dormancy’ where the differential expression of key cell surface antigens on oral epithelial cells may keep the recruited immune effector cells in a state of unresponsiveness, thus contributing to the long term quiescent period observed in many periodontal and endodontic lesions.
Isolation of genes expressed during compatible interactions between leaf rust (Puccinia triticina) and wheat using cDNA‐AFLP
Authors: Zhang Lin , Meakin Helen , Dickinson Matt
Published: October 2003

The rust fungi are obligate biotrophic pathogens that depend on living host tissue for their growth. In compatible interactions they go through a number of developmental stages to form intercellular hyphae and haustoria within host cells, through which they obtain their nutrients. Here we have exploited the cDNA‐AFLP technique to isolate fragments of wheat and rust genes that are expressed at specific defined time‐points during the infection process. A number of these sequences were used as probes in Northern hybridizations and in RT‐PCR to confirm their expression patterns, and were also characterized by PCR analysis and Southern hybridizations to determine whether they are of fungal or wheat origin. A cDNA library was constructed from pooled RNAs extracted from days 5 and 7 after inoculation, and this library was screened to isolate full‐length cDNAs of selected sequences. Sequence analysis of these cDNA fragments and clones revealed similarities amongst the fungal genes to a chitinase, a sorbitol utilization protein, an arabinitol dehydrogenase and a proteasome regulatory unit, whilst in wheat, we identified sequences with homology to a katanin and a cell enlargement protein.
The influence of dissolved nutrients and particulate organic matter quality on microbial respiration and biomass in a forest stream
Authors: Stelzer Robert S. , Heffernan James , Likens Gene E.
Published: October 2003

1. Although dissolved nutrients and the quality of particulate organic matter (POM) influence microbial processes in aquatic systems, these factors have rarely been considered simultaneously. We manipulated dissolved nutrient concentrations and POM type in three contiguous reaches (reference, nitrogen, nitrogen + phosphorus) of a low nutrient, third‐order stream at Hubbard Brook Experimental Forest (U.S.A). In each reach we placed species of leaves (mean C : N of 68 and C : P of 2284) and wood (mean C : N of 721 and C : P of 60 654) that differed in elemental composition. We measured the respiration and biomass of microbes associated with this POM before and after nutrient addition.

2. Before nutrient addition, microbial respiration rates and biomass were higher for leaves than for wood. Respiration rates of microbes associated with wood showed a larger response to increased dissolved nutrient concentrations than respiration rates of microbes associated with leaves, suggesting that the response of microbes to increased dissolved nutrients was influenced by the quality of their substrate.

3. Overall, dissolved nutrients had strong positive effects on microbial respiration and fungal, but not bacterial, biomass, indicating that microbial respiration and fungi were nutrient limited. The concentration of nitrate in the enriched reaches was within the range of natural variation in forest streams, suggesting that natural variation in nitrate among forest streams influences carbon mineralisation and fungal biomass.
Laboratory experiments on the impact of biofilms on the plankton of a large river
Authors: Weitere Markus , Schmidt‐Denter Kerstin , Arndt Hartmut
Published: October 2003

1. Benthic organisms can have a strong effect on the plankton in rivers, although normally only members of the macrofauna are considered as important consumers. In the present study we conducted experiments on four different dates (in December, March, June and September) to assess the potential role of periphytic heterotrophic flagellates (HF), ciliates and rotifers in the control of potamoplankton (bacteria, algae, HF and ciliates).

2. Natural periphyton was established on the walls of circular flow channels by exposing them to river water (River Rhine, Germany). The experimental channels (with periphyton) and control channels (without periphyton) were filled with riverine water and the increase rates of planktonic bacteria, algae, HF and oligotrich ciliates were determined for the two treatments.

3. The abundance of periphytic ciliates and rotifers at the beginning of the four experiments showed large differences with low values in December and March, and high values in June and September. Dominant potential consumers of plankton were the heterotrich ciliate Stentor sp. and bdelloid rotifers.

4. The rates of increase of planktonic algae, HF and ciliates were significantly smaller in the presence of periphyton compared with those in their absence. Significant interactions between the treatment (with and without periphyton) and the time of experiment were found for the planktonic HF and algae, indicating that the impact of the periphyton varied temporarily. The planktonic groups responded differently to the periphyton with the planktonic HF showing the highest loss rate. Significant differences were also found among the loss rates of different HF groups and different diatom size classes.

5. These laboratory experiments demonstrate that periphytic ciliates and rotifers are potentially important consumers of different planktonic groups. The quantitative impact of periphyton on plankton with respect to the selective feeding needs further attention.
Specificity of cicada calling songs in the genus Tibicina (Hemiptera: Cicadidae)
Authors: Sueur Jérôme , Aubin Thierry
Published: October 2003

Abstract.  Males of Tibicina cicada species produce a sustained and monotonous calling song by tymbal activity. This acoustic signal constitutes the first step in pair formation, attracting females at long range, and is involved in male–male interactions. The specificity of this signal was investigated for the first time for seven species and one subspecies of Tibicina occurring in France. This analysis was achieved by describing tymbal anatomy, tymbal mechanism and calling song structure. Male calling songs are emitted following the same general scheme: tymbals are activated alternately and the successive buckling of the sclerotized ribs that they bear produces a regular succession of groups of pulses. The structural and mechanical properties shared by Tibicina species and subspecies lead to a considerable uniformity of the signal shape. Nevertheless, a principal component analysis applied to eight temporal and three frequency parameters revealed differences between the signals of the species studied. In particular, calling songs differed in groups of pulse rate and/or in peak of the second frequency band (carrier frequency). These acoustic differences are probably linked to differences in the numbers of tymbal ribs and body size. Groups of pulse rate and/or peak of the second frequency band could encode specific information. However, Tibicina calling songs may not act as distinct specific‐mate recognition systems and may not play a leading role in the mating isolation process; rather, they might merely belong to a complex set of specific spatial, ecological, ethological and morphological characters that ensure syngamy.
Crystal structure of the disulfide bond‐deficient azurin mutant C3A/C26A
Authors: Bonander Nicklas , Leckner Johan , Guo Hongwei , Karlsson B. Göran , Sjölin Lennart
Published: October 2003

Azurin has a β‐barrel fold comprising eight β‐strands and one α helix. A disulfide bond between residues 3 and 26 connects the N‐termini of β strands β1 and β3. Three mutant proteins lacking the disulfide bond were constructed, C3A/C26A, C3A/C26I and a putative salt bridge (SB) in the C3A/S25R/C26A/K27R mutant. All three mutants exhibit spectroscopic properties similar to the wild‐type protein. Furthermore, the crystal structure of the C3A/C26A mutant was determined at 2.0 Å resolution and, in comparison to the wild‐type protein, the only differences are found in the immediate proximity of the mutation. The mutants lose the 628 nm charge‐transfer band at a temperature 10–22 °C lower than the wild‐type protein. The folding of the zinc loaded C3A/C26A mutant was studied by guanidine hydrochloride (GdnHCl) induced denaturation monitored both by fluorescence and CD spectroscopy. The midpoint in the folding equilibrium, at 1.3 m GdnHCl, was observed using both CD and fluorescence spectroscopy. The free energy of folding determined from CD is −24.9 kJ·mol−1, a destabilization of ≈ 20 kJ·mol−1 compared to the wild‐type Zn2+‐protein carrying an intact disulfide bond, indicating that the disulfide bond is important for giving azurin its stable structure. The C3A/C26I mutant is more stable and the SB mutant is less stable than C3A/C26A, both in terms of folding energy and thermal denaturation. The folding intermediate of the wild‐type Zn2+‐azurin is not observed for the disulfide‐deficient C3A/C26A mutant. The rate of unfolding for the C3A/C26A mutant is similar to that of the wild‐type protein, suggesting that the site of the mutation is not involved in an early unfolding reaction.
Diversity of bacteriorhodopsins in different hypersaline waters from a single Spanish saltern
Authors: Papke R. Thane , Douady Christophe J. , Doolittle W. Ford , Rodríguez‐Valera Francísco
Published: October 2003

Haloarchaeal rhodopsins are a diverse group of transmembrane proteins that use light energy to drive several different cellular processes. Two rhodopsins, bacteriorhodopsin and halorhodopsins, are H+ and Cl– ion pumps, respectively, and two rhodopsins, sensory rhodopsin I and II, regulate phototaxis. Bacteriorhodopsin is of special interest as it is a non‐chlorophyll‐based type of phototrophy (i.e. generation of chemical energy from light energy). However, very little is known about the diversity and distribution of rhodopsin genes in hypersaline environments. Here, we have used environmental PCR and cloning techniques to directly retrieve rhodopsin genes from three different salinity ponds located in a sea salt manufacturing facility near Alicante, Spain. Our survey resulted in the discovery of previously concealed variation including what is hypothesized to be bacteriorhodopsin genes from the uncultivated square morphotype that dominates these environments. In some instances, identical genes were discovered in seemingly different habitats suggesting that some haloarchaea are present over widely varying concentrations of salt.
Erythema multiforme ID reaction in atypical dermatophytosis: a case report
Authors: Atzori L , Pau M , Aste M
Published: October 2003

Background  Erythema multiforme (EM) is an uncommon mucocutaneous disorder, characterized by widespread erythematous‐oedematous targetoid lesions, considered as a reaction pattern to many different stimuli.

Observation  Presentation is made of a classical EM eruption concomitant to an inflammatory, atypical dermatophytosis of the ala nasi, observed in a 37‐year‐old male at the Dermatology Department of Cagliari, Italy.

Methods  Laboratory investigations revealed normal complete blood count and biochemistry profile. A direct microscopic examination with 20% potassium hydroxide of the nasal skin scales and of the vibrissae indicated the presence of dermatophyte hyphae and spores invading the rhinothrix. Culture confirmed a Trycophyton mentagrophytes infection. Specific determination of antiviral immunity in the blood (TORCH) was negative for recent infections, while the cell‐mediated response, investigated with a delayed skin multitest, showed a marked positivity for the tricophyton antigen. Systemic therapy with terbinafine (250 mg/day) led to complete clinical and mycological recovery of the atypical ringworm in 30 days. Multiforme lesions rapidly improved and completely disappeared in 7 days.

Conclusions  ID reaction to a distant focus of dermatophyte infection very rarely presents as EM. The presented case fits all the essential criteria required for the diagnosis of an ID reaction. The atypical clinical presentation of the ringworm infection, with marked involvement of the intranasal hairs, seems to have induced an inflammatory allergic response, similar to that evoked by sycosis.
Influence of intravenous immunoglobulin therapy on autoantibody titres to BP Ag1 and BP Ag2 in patients with bullous pemphigoid
Authors: Sami N , Ali S , Bhol KC , Ahmed AR
Published: October 2003

Background   Bullous pemphigoid (BP) is a subepidermal autoimmune blistering disease, which is characterized by blisters on the skin. Autoantibodies to components of the basement membrane zone are usually observed in the sera of patients with BP. Autoantibodies to the bullous pemphigoid antigens (BP Ag1, 230‐kDa desmoplakin protein, and BP Ag2, 180‐kDa hemidesmosomal protein) are present in the sera of BP patients.

Objective   The objective of this study was to report the influence of intravenous immunoglobulin (IVIg) therapy on autoantibody titres to BP Ag1 and BP Ag2.

Methods   In this prospective study, we measured autoantibody titres to both BP Ag1 and BP Ag2, in 10 patients with severe BP, over a period of 18 consecutive months on each patient, using an immunoblot assay.

Results   Prior to the initiation of IVIg therapy, the sera of nine patients demonstrated the presence of high autoantibody titres to both BP Ag1 and BP Ag2. One patient had autoantibodies to BP Ag1 only. A statistically significant decline in the autoantibody titres to both BP Ag1 and BP Ag2 was observed after 3 months of receiving the first cycle of IVIg therapy. This gradual decline in autoantibody titres continued until patients were observed to have non‐detectable titres to BP Ag1 after 11 months and to BP Ag2 after 10 months of receiving IVIg therapy. Once patients achieved non‐detectable titres, these patients were considered to be in a serological remission. This serological remission was sustained for an additional 7 months of observation.

Conclusion   Autoantibody titres to BP Ag1 and BP Ag2 can be used to monitor the serological response to treatment in patients with BP. Patients with severe BP who are treated with IVIg therapy, as described in our protocol, achieve a long‐term serological remission.
Antioxidant activity, lipid peroxidation and skin diseases. What's new
Authors: Briganti S , Picardo M
Published: October 2003

Due to its interface function between the body and the environment, the skin is chronically exposed to both endogenous and environmental pro‐oxidant agents, leading to the harmful generation of reactive oxygen species (ROS). There is compelling evidence that oxidative stress is involved in the damage of cellular constituents, such as DNA, cell membrane lipids or proteins. To protect the skin against the over‐load of oxidant species, it contains a well‐organised system of both chemical and enzymatic antioxidant which are able to work in a synergistic manner. Skin antioxidant network protects cells against oxidative injury and prevent the production of oxidation products, such as 4‐hydroxy‐2‐nonenal or malonaldehyde, which are able to induce protein damage, apoptosis or release of pro‐inflammatory mediators, such as cytokines. When oxidative stress overwhelms the skin antioxidant capacity the subsequent modification of cellular redox apparatus leads to an alteration of cell homeostasis and a generation of degenerative processes. Topical application or oral administration of antioxidants has been recently suggested as preventive therapy for skin photoaging and UV‐induced cancer. The recognition that ROS can act as second messengers in the induction of several biological responses, such as the activation of NF‐kB or AP‐1, the generation of cytokines, the modulation of signalling pathways, etc., has led many researchers to focus on the possible effects of antioxidants in many pathological processes. The recent demonstration that the peroxisome proliferators‐activated receptors, whose natural ligands are polyunsaturated fatty acids and theirs oxidation products, have a central role in the induction of some skin diseases, such as psoriasis or acne, has indicated new links between free radicals and skin inflammation. Based on these findings, the review summarises the possible correlations between antioxidant imbalance, lipid oxidative breakage and skin diseases, from both a pathological and therapeutic points of view.
FROM SYNTENY TO SYNERGY — SAVING PLANT GENETIC RESOURCES FOR POSTERITY
Authors: Bailey John
Published: October 2003

Books reviewed:

Engels, J.M.M., Rao, V.R., Brown, A.H.D. & Jackson, M.T. (eds), Managing plant genetic diversity.
The effects of herbivory and competition on the invasive alien plant Senecio inaequidens (Asteraceae)
Authors: Scherber Christoph , Crawley Michael J. , Porembski Stefan
Published: October 2003

Abstract.  Senecio inaequidens DC. (Asteraceae) is an invasive alien plant introduced to Europe from South Africa in around 1896. It contains pyrrolizidine alkaloids that are toxic to livestock and humans. S. inaequidens would therefore be an economic and ecological problem if it became established and abundant in natural or farmed grassland ecosystems.

 We conducted field experiments using a split‐plot design to determine the effects of rabbit grazing, interspecific plant competition, mollusc and insect herbivory on growth, survival and reproduction of S. inaequidens. Plants were grown from seeds of three different ecotypes under standardized greenhouse conditions and transplanted into field plots. Rabbits (Oryctolagus cuniculus L.) were excluded from experimental plots using rabbit fences. Competition was manipulated by either creating subplots with bare ground or leaving the vegetation cover intact. Data were recorded between June and August 2002.

 Ecotypes differed significantly in morphological parameters, and in their responses to invertebrate herbivory. Interspecific plant competition and rabbit grazing significantly reduced growth and reproduction of S. inaequidens. Regrowth shoots of S. inaequidens produced after rabbit grazing were not subsequently eaten by rabbits. Unpalatability of regrowth shoots may be attributable to changes in pyrrolizidine alkaloid composition with plant age. Mollusc herbivory significantly reduced the number of capitulae produced. We found adults of Longitarsus jacobaeae Waterhouse (Coleoptera: Chrysomelidae), a specialist herbivore of European Senecio jacobaea L. (Asteraceae), feeding on 79% of S. inaequidens plants. 320 larvae of Tyria jacobaeae L. (Lepidoptera: Arctiidae) did not feed on S. inaequidens under free‐choice field conditions.

 We conclude that S. inaequidens is able to survive and reproduce in disturbed grassland ecosystems. L. jacobaeae might be a suitable agent for biological control of S. inaequidens in European introduced populations in the future.
Prevalence and Severity of Urinary Incontinence in Elderly Mexican‐American Women
Authors: Espino David V. , Palmer Ray F. , Miles Toni P. , Mouton Charles P. , Lichtenstein Michael J. , Markides Kyriakos P.
Published: October 2003

Objectives: To measure prevalence and characteristics of urinary incontinence in older Mexican‐American women.

Design: Cross‐sectional analysis of a longitudinal survey of a representative sample of older Mexican Americans.

Setting: Five southwestern states in the United States.

Participants: A total of 1,589 Mexican‐American women, aged 65 and older who were part of the Hispanic Established Population for the Epidemiologic Study of the Elderly.

Measurements: Self‐reported psychosocial, demographic, and health variables; self‐reported history of symptoms of urinary incontinence.

Results: Two hundred thirty‐nine (15%) of the 1,589 Mexican‐American women reported having urinary incontinence. Almost 33% reported urge incontinence symptoms, 10% reported stress incontinence symptoms, and 42% had symptoms suggestive of mixed incontinence. Thirty‐five percent of subjects reported incontinence episodes with moderate to large amounts of urine loss, and 15% reported that their urinary symptoms kept them from engaging in social activities. Age and body mass index were risk factors for incontinence (P=.02 and P=.03, respectively).

Conclusion: This is the first community‐based survey examining rates of urinary incontinence in Mexican‐American women. The prevalence of urinary incontinence may be lower in older Mexican‐American women than in the general population. They may also have a higher percentage of urge as opposed to stress incontinence symptoms and may suffer from moderate to large volumes of urine loss associated with their incontinence episodes.
Are Nursing Homes Appropriate for Older Adults with Severe Mental Illness? Conflicting Consumer and Clinician Views and Implications for the Olmstead Decision
Authors: Bartels Stephen J. , Miles Keith M. , Dums Aricca R. , Levine Kristin J.
Published: October 2003

Objectives: In response to the recent Olmstead decision, to compare consumer and clinician perspectives on the appropriateness of nursing home settings for older adults with severe mental illness (SMI) in relation to clinical characteristics and care needs.

Design: Cross‐sectional, descriptive, correlational study.

Setting: Ten community mental health centers and two state‐funded nursing homes specializing in long‐term care for older persons with SMI.

Participants: Consumers of mental health services in the community (n=115) and in nursing homes (n=106), aged 60 and older, with SMI. Sixty‐four clinicians (51% registered nurses, 29% masters‐level clinicians, and 20% certified social workers) conducted ratings.

Measurements: Consumers and their clinicians were independently asked to determine the most appropriate care setting for each consumer based on care needs from three alternatives: nursing home, congregate (group) living setting, or individual apartment/home. Clinical characteristics of participants with SMI were rated using the Mini‐Mental State Examination, Brief Psychiatric Rating Scale, Specific Level of Function Scale, Cumulative Illness Rating Scale for Geriatrics, a modified memory and orientation subscale from the Clinical Dementia Rating Scale, and an item from the Minimum Data Set related to reasoning.

Results: Of nursing home residents with SMI who did not have severe cognitive impairment, 40% (n=42) and 51% (n=54) were considered by consumers or by their clinician, respectively, to be more appropriate for a community‐based setting, but there was a low level of agreement (only 27.6%; no better than chance) between consumers and clinicians on which nursing home residents were most appropriate for living in the community. Determinations by clinicians were associated with clinical need (diagnosis and less‐severe behavioral problems), whereas there was no association between clinical needs and level of care determinations by consumers. Finally, clinicians considered a group home necessary for 93.7% of nursing home residents judged to be more appropri‐ate for a community‐based setting, whereas 90.5% of con‐sumers stated that an apartment or individual home was indicated.

Conclusion: State implementation of the Olmstead decision will need to consider major differences in perspectives between clinicians and consumers on the most appropriate long‐term care setting for older persons with SMI.
Factors influencing moderate to severe reactions to PLT transfusions: experience of the TRAP multicenter clinical trial
Authors: Enright Helen , Davis Kathryn , Gernsheimer Terry , McCullough Jeffrey J. , Woodson Robert , Slichter Sherrill J.
Published: October 2003

BACKGROUND:  During the Trial to Reduce Alloimmunization to Platelets (TRAP Trial), data were prospectively collected for 8769 PLT transfusions regarding the frequency of moderate to severe PLT transfusion reactions.

STUDY DESIGN AND METHODS:  At seven centers, 598 patients were randomly assigned to receive unmodified pooled random‐donor PLT concentrates (PCs), UV‐B‐irradiated PCs, filtered PCs, or filtered random‐donor apheresis PLTs.

RESULTS:  Moderate to severe transfusion reactions were an increase in temperature of at least 2°C, chills with rigors, extensive urticaria, dyspnea, cyanosis, or bronchospasm. These reactions occurred with 2.2 percent of the transfusions in 22 percent of the patients. Transfusion reactions were associated with WBC counts of more than 5 × 106 per transfusion (p = 0.002) and transfusions stored for more than 48 hours (p = 0.02). PLT counts before transfusion were significantly lower for transfusions associated with reactions (p = 0.005). Neither UV‐B irradiation nor apheresis PLTs independently influenced reaction rates. The PLT increment at 1 hour after transfusion was lower for transfusions associated with reactions (p = 0.004), and the frequency of reactions was higher in PLT refractory patients (p < 0.001).

CONCLUSIONS:  The provision of either fresh and/or WBC‐reduced PLTs may decrease the frequency of PLT transfusion reactions and improve PLT transfusion efficacy.