bluuebunny/crossref_metadata_2025 huggingface dataset:
Virulence of Agrobacterium tumefaciens requires phosphatidylcholine in the bacterial membrane
Authors: Wessel Mirja , Klüsener Sonja , Gödeke Julia , Fritz Christiane , Hacker Stephanie , Narberhaus Franz
Published: September 2006

Phosphatidylcholine (PC, lecithin) has long been considered a solely eukaryotic membrane lipid. Only a minority of all bacteria is able to synthesize PC. The plant‐transforming bacterium Agrobacterium tumefaciens encodes two potential PC forming enzymes, a phospholipid N‐methyltransferase (PmtA) and a PC synthase (Pcs). We show that PC biosynthesis and tumour formation on Kalanchoë plants was impaired in the double mutant. The virulence defect was due to a complete lack of the type IV secretion machinery in the Agrobacterium PC mutant. Our results strongly suggest that PC in bacterial membranes is an important determinant for the establishment of host–microbe interactions.
Biochemical and genetic characterization of an early step in a novel pathway for the biosynthesis of aromatic amino acids and p‐aminobenzoic acid in the archaeon Methanococcus maripaludis
Authors: Porat Iris , Sieprawska‐Lupa Magdalena , Teng Quincy , Bohanon Fredrick J. , White Robert H. , Whitman William B.
Published: September 2006

Methanococcus maripaludis is a strictly anaerobic, methane‐producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6‐deoxy‐5‐ketofructose‐1‐phosphate (DKFP) pathway for the biosynthesis of aromatic amino acids (AroAAs) and p‐aminobenzoic acid (PABA) was demonstrated in M. maripaludis. Moreover, PABA was shown to be derived from an early intermediate in AroAA biosynthesis and not from chorismate. Following metabolic labelling with [U‐13C]‐acetate, the expected enrichments for phenylalanine and arylamine derived from PABA were observed. DKFP pathway activity was reduced following growth with aryl acids, an alternative source of the AroAAs. Lastly, a deletion mutant of aroA′, which encodes the first step in the DKFP pathway, required AroAAs and PABA for growth. Complementation of the mutants by an aroA′ expression vector restored the wild‐type phenotype. In contrast, a deletion of aroB′, which encodes the second step in the DKFP pathway, did not require AroAAs or PABA for growth. Presumably, methanococci contain an alternative activity for this step. These results identify the initial reactions of a new pathway for the biosynthesis of PABA in methanococci.
Experimental African trypanosomiasis: lack of effective CD1d‐restricted antigen presentation
Authors: SHI M. Q. , WANG C.‐R. , WEI G. J. , PAN W. L. , APPLEYARD G. , TABEL H.
Published: September 2006

BALB/c mice are highly susceptible to African trypanosomiasis, whereas C57BL/6 mice are relatively resistant. Other investigators have reported that the synthesis of IgG antibodies to purified membrane form of variant surface glycoprotein (mfVSG) of Trypanosoma brucei is CD1 restricted. In this study, we examine the role of the CD1d/NKT cell pathway in susceptibility and resistance of mice to infection by African trypanosomes. Administration of anti‐CD1d antibodies to Trypanosoma congolense‐infected BALB/c mice neither affects the parasitemia nor the survival time. Correspondingly, CD1d–/– and CD1d+/+ BALB/c mice infected with T. congolense or T. brucei show no differences in either parasitaemia or survival time. The course of disease in relative resistant C57BL/6 mice infected with T. congolense is also not affected by the absence of CD1d. Parasitaemia, survival time, and plasma levels of IgG2a and IgG3 parasite‐specific antibodies in infected CD1d–/– C57BL/6 are not different from those of infected CD1d+/+ C57BL/6 mice. We conclude that CD1d‐restricted immune responses do not play an important role in susceptibility/resistance of mice infected with virulent African trypanosomes. We speculate that virulent trypanosomes have an evasion mechanism that prevents the induction of a parasite‐specific, CD1d‐restricted immune response by the host.
Mitochondria as a connected population: ensuring continuity of the mitochondrial genome during plant cell dedifferentiation through massive mitochondrial fusion
Authors: Sheahan Michael B. , McCurdy David W. , Rose Ray J.
Published: September 2006

Mitochondrial fusion in plants and its role in development are poorly understood. Cultured tobacco mesophyll protoplasts provide an excellent experimental system for visualizing mitochondrial dynamics. Before protoplasts first divide, mitochondria undergo a phase of extensive elongation before fission causes an increase in number, followed by actin filament (AF)‐dependent dispersion that distributes mitochondria uniformly throughout the cytoplasm. Here, by fusing protoplasts containing either green fluorescent protein‐ or MitoTracker‐labelled mitochondria, we show that elongation results from fusion during early (4–8 h) protoplast culture. This massive mitochondrial fusion (MMF) leads to near‐complete mixing of the mitochondrial population within 24 h. Staining isolated mitochondria with 4′,6‐diamidino‐2‐phenylindole (DAPI) revealed that in freshly prepared protoplasts mitochondrial nucleoids were unequally distributed, with many mitochondria failing to stain with DAPI, suggesting the presence of an incomplete mitochondrial genome. Following MMF, nucleoids were distributed evenly throughout the population, thereby ensuring continuity of the mitochondrial genome in daughter cells. Massive mitochondrial fusion appears to be specific to dedifferentiation, since it also occurs in mesophyll protoplasts of Arabidopsis and Medicago but not in protoplasts from already dedifferentiated cells such as BY‐2 or callus cultures. Efficient MMF requires an inner membrane electrical gradient, cytoplasmic protein synthesis, microtubules and functional kinesin but not ATP or AFs, indicating fundamental differences from mitochondrial fusion in non‐plant systems. Our studies reveal that individual mitochondria are connected over time by fusion events, a finding that allows a clearer interpretation of how novel mitochondrial genotypes develop following cell fusion, and indicates that developmentally regulated fusion ensures continuity of the mitochondrial genome.
The genetics and genomics of the drought response in Populus
Authors: Street Nathaniel Robert , Skogström Oskar , Sjödin Andreas , Tucker James , Rodríguez‐Acosta Maricela , Nilsson Peter , Jansson Stefan , Taylor Gail
Published: September 2006

The genetic nature of tree adaptation to drought stress was examined by utilizing variation in the drought response of a full‐sib second generation (F2) mapping population from a cross between Populus trichocarpa (93‐968) and P. deltoides Bart (ILL‐129) and known to be highly divergent for a vast range of phenotypic traits. We combined phenotyping, quantitative trait loci (QTL) analysis and microarray experiments to demonstrate that ‘genetical genomics’ can be used to provide information on adaptation at the species level. The grandparents and F2 population were subjected to soil drying, and contrasting responses to drought across genotypes, including leaf coloration, expansion and abscission, were observed, and QTL for these traits mapped. A subset of extreme genotypes exhibiting extreme sensitivity and insensitivity to drought on the basis of leaf abscission were defined, and microarray experiments conducted on these genotypes and the grandparent species. The extreme genotype groups induced a different set of genes: 215 and 125 genes differed in their expression response between groups in control and drought, respectively, suggesting species adaptation at the gene expression level. Co‐location of differentially expressed genes with drought‐specific and drought‐responsive QTLs was examined, and these may represent candidate genes contributing to the variation in drought response.
Regulation of hormone metabolism in Arabidopsis seeds: phytochrome regulation of abscisic acid metabolism and abscisic acid regulation of gibberellin metabolism
Authors: Seo Mitsunori , Hanada Atsushi , Kuwahara Ayuko , Endo Akira , Okamoto Masanori , Yamauchi Yukika , North Helen , Marion‐Poll Annie , Sun Tai‐ping , Koshiba Tomokazu , Kamiya Yuji , Yamaguchi Shinjiro , Nambara Eiji
Published: September 2006

In a wide range of plant species, seed germination is regulated antagonistically by two plant hormones, abscisic acid (ABA) and gibberellin (GA). In the present study, we have revealed that ABA metabolism (both biosynthesis and inactivation) was phytochrome‐regulated in an opposite fashion to GA metabolism during photoreversible seed germination in Arabidopsis. Endogenous ABA levels were decreased by irradiation with a red (R) light pulse in dark‐imbibed seeds pre‐treated with a far‐red (FR) light pulse, and the reduction in ABA levels in response to R light was inhibited in a phytochrome B (PHYB)‐deficient mutant. Expression of an ABA biosynthesis gene, AtNCED6, and the inactivation gene, CYP707A2, was regulated in a photoreversible manner, suggesting a key role for the genes in PHYB‐mediated regulation of ABA metabolism. Abscisic acid‐deficient mutants such as nced6‐1, aba2‐2 and aao3‐4 exhibited an enhanced ability to germinate relative to wild type when imbibed in the dark after irradiation with an FR light pulse. In addition, the ability to synthesize GA was improved in the aba2‐2 mutant compared with wild type during dark‐imbibition after an FR light pulse. Activation of GA biosynthesis in the aba2‐2 mutant was also observed during seed development. These data indicate that ABA is involved in the suppression of GA biosynthesis in both imbibed and developing seeds. Spatial expression patterns of the AtABA2 and AAO3 genes, responsible for last two steps of ABA biosynthesis, were distinct from that of the GA biosynthesis gene, AtGA3ox2, in both imbibed and developing seeds, suggesting that biosynthesis of ABA and GA in seeds occurs in different cell types.
PICKLE is required for SOLITARY‐ROOT/IAA14‐mediated repression of ARF7 and ARF19 activity during Arabidopsis lateral root initiation
Authors: Fukaki Hidehiro , Taniguchi Naohide , Tasaka Masao
Published: September 2006

Lateral root (LR) formation in Arabidopsis is regulated by auxin signaling through AUXIN RESPONSE FACTOR transcriptional activators, ARF7 and ARF19, and auxin/indole‐3‐acetic acid (Aux/IAA) repressors, including SOLITARY‐ROOT (SLR)/IAA14. Previous studies have strongly suggested that, in the gain‐of‐function slr‐1 mutant, stabilized mutant IAA14 (mIAA14) protein inactivates ARF7/19 functions, thereby completely blocking LR initiation. However, the mechanism of inactivation is still unknown. We have now identified an extragenic suppressor mutation of slr‐1, suppressor of slr2 (ssl2), which specifically restores LR formation in the slr‐1 mutant, and have found that SSL2 negatively regulates the auxin‐induced pericycle cell divisions required for LR initiation. The SSL2 gene encodes PICKLE (PKL), a homologue of the animal chromatin‐remodeling factor CHD3/Mi‐2, and LR formation restored in pkl/ssl2 slr‐1 mutants depends on ARF7/19 functions, suggesting that ARF7/19‐dependent transcription takes place if there is a pkl/ssl2 mutation in slr‐1. In animals, Mi‐2 represses transcription as a subunit of the NuRD/Mi‐2 complex containing histone deacetylases (HDACs). Inhibition of HDAC activity by trichostatin A also results in LR formation in the slr‐1 mutant, but not in the slr‐1 arf7 arf19 triple mutant, suggesting that normal HDAC activity is required for the mIAA14‐mediated inactivation of ARF7/19 functions in LR initiation. Taken together, our data suggest that PKL/SSL2‐mediated chromatin remodeling negatively regulates auxin‐mediated LR formation in Arabidopsis.
Identification of plant cytoskeleton‐interacting proteins by screening for actin stress fiber association in mammalian fibroblasts
Authors: Abu‐Abied Mohamad , Golomb Lior , Belausov Eduard , Huang Shanjin , Geiger Benjamin , Kam Zvi , Staiger Christopher J. , Sadot Einat
Published: September 2006

Taking advantage of the high conservation of the cytoskeleton building blocks actin and tubulin between plant and animal kingdoms, we developed a functional genomic screen for the isolation of new plant cytoskeleton‐binding proteins that uses a mammalian cell expression system. A yellow fluorescent protein (YFP)‐fusion cDNA library from Arabidopsis was inserted into rat fibroblasts and screened for fluorescent chimeras localizing to cytoskeletal structures. The high‐throughput screen was performed by an automated microscope. An initial set of candidate genes identified in the screen was isolated, sequenced, the full‐length cDNAs were synthesized by RT‐PCR and tested by biochemical approaches to verify the ability of the genes to bind actin directly. Alternatively, indirect binding via interaction with other actin‐binding proteins was studied. The full‐length cDNAs were transferred back to plants as YFP chimeras behind the CAMV‐35S promoter. We give here two examples of new plant cytoskeletal proteins identified in the pilot screen. ERD10, a member of the dehydrin family of proteins, was localized to actin stress fibers in rat fibroblasts. Its direct binding to actin filaments was confirmed by several biochemical approaches. Touch‐induced calmodulin‐like protein, TCH2, was also localized to actin stress fibers in fibroblasts, but was unable to bind actin filaments directlyin vitro. Nevertheless, it did bind to the IQ domains of Arabidopsis myosin VIII in a calcium‐dependent manner. Further evidence for a cytoskeletal function of ERD10 was obtainedin planta; GFP‐ERD10 was able to protect the actin cytoskeleton from latrunculin‐mediated disruption inNicotiana benthamianaleaves.
Characterizing the composition and evolution of homoeologous genomes in hexaploid wheat through BAC‐end sequencing on chromosome 3B
Authors: Paux Etienne , Roger Delphine , Badaeva Ekatherina , Gay Georges , Bernard Michel , Sourdille Pierre , Feuillet Catherine
Published: September 2006

Bread wheat (Triticum aestivum) is one of the most important crops worldwide. However, because of its large, hexaploid, highly repetitive genome it is a challenge to develop efficient means for molecular analysis and genetic improvement in wheat. To better understand the composition and molecular evolution of the hexaploid wheat homoeologous genomes and to evaluate the potential of BAC‐end sequences (BES) for marker development, we have followed a chromosome‐specific strategy and generated 11 Mb of random BES from chromosome 3B, the largest chromosome of bread wheat. The sequence consisted of about 86% of repetitive elements, 1.2% of coding regions, and 13% remained unknown. With 1.2% of the sequence length corresponding to coding sequences, 6000 genes were estimated for chromosome 3B. New repetitive sequences were identified, including a Triticineae‐specific tandem repeat (Fat) that represents 0.6% of the B‐genome and has been differentially amplified in the homoeologous genomes before polyploidization. About 10% of the BES contained junctions between nested transposable elements that were used to develop chromosome‐specific markers for physical and genetic mapping. Finally, sequence comparison with 2.9 Mb of random sequences from the D‐genome of Aegilops tauschii suggested that the larger size of the B‐genome is due to a higher content in repetitive elements. It also indicated which families of transposable elements are mostly responsible for differential expansion of the homoeologous wheat genomes during evolution. Our data demonstrate that BAC‐end sequencing from flow‐sorted chromosomes is a powerful tool for analysing the structure and evolution of polyploid and highly repetitive genomes.
Effect of manufacturing process parameters on virus inactivation by dry heat treatment at 80 °C in factor VIII
Authors: Roberts P. L. , Dunkerley C. , McAuley A. , Winkelman L.
Published: September 2006

Background and Objectives  Dry heat treatment at 80 °C for 72 h is used as a virus inactivation step for some coagulation factor concentrates such as Bio Products Laboratory's (BPL) factor VIII 8Y. In the current study, the effect of this process has been tested on a range of viruses. In addition the effect of various manufacturing process parameters on virus inactivation has been investigated.

Materials and Methods  Samples of product intermediate were obtained from manufacturing, spiked with virus and subjected to freeze drying and dry heat treatment. Virus inactivation was determined by infectivity assay.

Results  Freeze drying followed by dry heat treatment was effective for inactivating a wide range of enveloped and nonenveloped viruses. Sucrose or protein concentration had no effect on virus inactivation. Product presentation or the interruption of heat treatment also had no effect. The inactivation of some of the viruses was greater at higher residual water content but under such conditions the stability of the product was reduced.

Conclusion  This virus inactivation step was effective for a wide range of viruses and over the range of process conditions encountered in manufacturing. This demonstrates the robustness of this process step.
Optische Aufheller in der Pilzdiagnostik
Authors: Schroeder J. , Schaffrinski Meike , Rüchel R.
Published: September 2006

Die kontrastreiche Fluoreszenzfärbung mit Optischen Aufhellern aus der Gruppe der Diaminostilbene erlaubt eine schnelle, unkomplizierte Darstellung von Pilzelementen in klinischen Untersuchungsmaterialien und damit einen ersten Schritt zur Diagnose einer Mykose. Eine mikroskopische Differenzierung der verschiedenen Pilz‐Gattungen ist allerdings nur begrenzt möglich; diese bedarf vielmehr weiterführender Techniken wie z.B. der Immunhistochemie oder der in situ Hybridisierung.
Diuretics: A modern day treatment option? (Review Article)
Authors: GALLAGHER MARTIN , PERKOVIC VLADO , CHALMERS JOHN
Published: September 2006

SUMMARY:  The choice of drugs to initiate therapy for the management of hypertension remains contentious and diuretics are central to this controversy. Because most of the major trials involve complex treatment algorithms and allow diverse background treatments, one of the greatest challenges lies in separating out true class‐specific effects – for example, separating true class‐specific effects of diuretics from those of beta blockers. Despite these difficulties, the evidence confirms that diuretics are at least as effective as the newer first line groups in preventing cardiovascular events. The main area of doubt lies in relation to the risk of renal outcomes and of metabolic outcomes, such as new onset diabetes – where the evidence suggests that drugs that inhibit the renin‐angiotensin system may be more protective than all other drug classes. These issues are reflected in the most recent international guidelines, all of which include diuretics among the first‐line drugs for the treatment of hypertension, although they do differ on the role of diuretics in the initiation of therapy. Diuretics remain important for treating hypertension, especially in combination with other drug classes. The particular place of diuretics in the rank order of drugs must be tailored to suit the clinical situation in the individual patient. This will vary from a preferred option, as in black patients or elderly patients with systolic hypertension, to a second‐line option in patients at high risk of developing new onset diabetes.
Cardiac troponin levels in asymptomatic patients on the renal transplant waiting list
Authors: ROBERTS MATTHEW A , MACMILLAN NEIL , HARE DAVID L , RATNAIKE SUJIVA , SIKARIS KEN , FRAENKEL MARGARET B , IERINO FRANCESCO L
Published: September 2006

Aims:  Cardiac troponin levels predict mortality and cardiovascular events in asymptomatic patients receiving dialysis and may be a useful clinical tool to stratify high‐risk asymptomatic individuals.

Methods:  The present study examined levels of troponins I (cTnI) and T (cTnT) in patients with chronic renal impairment, patients receiving dialysis and renal transplant recipients. Patients receiving dialysis on the renal transplant waiting list were compared with those excluded from the list based on medical criteria. Median levels were compared using the Kruskal–Wallis test and proportions compared by chi‐squared.

Results:  Median troponin levels were higher in patients on dialysis than transplant recipients. Comparing patients receiving dialysis not listed compared with those listed for renal transplant, median cTnI levels were significantly higher (0.03 versus 0.02 µg/L, P < 0.01) whereas median cTnT levels were not. Patients listed for transplantation were younger, had less clinical cardiovascular disease and lower C‐reactive protein than those awaiting renal transplantation. The proportion of patients with elevated cTnT was not substantially different between patients awaiting renal transplantation (38%) and those excluded (52%). Levels of cTnI and cTnT were inversely related to renal function in predialysis and transplant patients, but were not related to time on dialysis for those receiving dialysis therapy.

Conclusion:  As patients awaiting renal transplantation are clinically screened for cardiovascular disease but have frequently elevated cardiac troponin levels, troponin may be a useful clinical tool to identify high‐risk asymptomatic patients on dialysis prior to renal transplantation. The influence of renal function on the interpretation of cardiac troponin and risk prediction requires further evaluation.
Combined therapy of low‐dose tacrolimus and prednisone in nephrotic syndrome with slight mesangial proliferation
Authors: MIAO LINING , SUN JING , YUAN HANG , JIA YE , XU ZHONGGAO
Published: September 2006

Aim:  Tacrolimus is a calcineurin inhibitor that has been increasingly used in transplant medicine. However, the efficacy and safety of combined therapy of low‐dose tacrolimus and prednisone in the treatment of nephrotic syndrome (NS) with slight mesangial proliferation has not been reported.

Patients and Methods:  Sixty patients with NS with slight mesangial proliferation were randomly divided into a prednisone therapy group (control), a combined low‐dose tacrolimus (2 mg/day) and a prednisone therapy group (tacrolimus group). The efficacy and safety of tacrolimus was analysed. The initial dose of prednisone was 1 mg/kg per day and 30 mg/day in the control group and tacrolimus group, respectively. The duration of treatment was 6 months.

Results:  After a 6‐month trial of combined low‐dose tacrolimus and prednisone, complete remission was achieved in 29 patients (96.66%) and partial remission in one patient (3.33%). In the control group, complete remission was achieved in 27 patients (90%) and partial remission in three patients (10%). A significant improvement in proteinuria levels was observed in the tacrolimus group compared with the control group, starting at the second week and remaining throughout the study period. Furthermore, a significant improvement in serum albumin levels was observed in the tacrolimus group compared with the control group, starting at the first month and remaining until the third month. The main side‐effect was obesity (100%) and acne (46.66%) in the control group. However, these adverse events were not observed in the tacrolimus group.

Conclusion:  The results demonstrated that combined therapy of low‐dose tacrolimus and prednisone is an effective and safe therapeutic method for NS with slight mesangial proliferation.
Ambulatory anesthesia and the lack of consensus among Canadian pediatric anesthesiologists: a survey
Authors: ABU‐SHAHWAN IBRAHIM
Published: September 2006

Background:  The purpose of this study was to assess the current selection criteria for outpatient surgery in children among Canadian pediatric anesthesiologists.

Methods:  A survey specifying 20 different medical situations was sent to 120 members of the Canadian Pediatric Anesthesia Society. Members were asked to indicate if they agreed or refused to provide anesthesia for children with one or more clinical condition or symptoms. Consensus was defined as a >70% majority opinion.

Results:  Sixty‐four pediatric anesthesiologists replied (53.3%). For 13 conditions there was no consensus among members. Seven scenarios resulted in a consensus of either providing or not providing anesthesia in an outpatient setting. The majority of members would agree to provide anesthesia for the following scenarios: (i) an asymptomatic child with recurrent otitis media, rectal temperature of 38°C; (ii) the same child with chronic nasal discharge for bilateral myringotomy and tube placement; (iii) an asymptomatic child with sickle‐cell disease (SCD) for cast change; (iv) an asymptomatic child with asthma and fever for bilateral myringotomy and tube placement (BMT); (v) a morbidly obese child with congested nose for BMT; and (vi) a child with well controlled insulin dependent diabetes mellitus for magnetic resonance imaging (MRI). Most members would refuse to provide outpatient anesthesia in an asymptomatic child with SCD for tonsillectomy.

Conclusion:  Further studies are needed to establish evidence‐based medicine to support guidelines that would allow one to select children safely for ambulatory surgery.
Anesthesia for repair of gastroschisis in thoracopagus twins: a case report
Authors: LONNÉE HERMAN A. , CHETTY VANDHANA , RAWAILIU VERENIKI
Published: September 2006

The first pair of live conjoined twins in Fiji were delivered in June 2004. Their union was unexpected and in addition they had gastroschisis requiring urgent surgery. With limited resources available there was uncertainty about the degree of sharing of the major organs. Whilst the media speculated on separation overseas, the local team of doctors were faced with a rare emergency. Surgical repair of the abdominal defect was performed using a combined general and regional anesthesia technique. The thoracopagus twins died 3 days postoperatively in the Neonatal Intensive Care Unit. Perioperative management is discussed.
Bacterial community shifts in organically perturbed sediments
Authors: Bissett Andrew , Burke Chris , Cook Perran L. M. , Bowman John P.
Published: September 2006

Bacterial abundance, diversity and sediment function were investigated in organically perturbed sediments under Tasmanian salmon (Salmo salar) farms and adjacent reference sites. Bacterial numbers increased as farming and organic loading progressed through the farm stocking cycle and declined during the fallow period, although not to prestocking levels. Bacterial numbers ranged between approximately 2 × 108 and 3 × 109 cells per gram of sediment and were higher at cage sites than reference sites. Microelectrode and respiration data also demonstrated a clear effect of organic loading on sediments. Denaturing gradient gel electrophoresis (DGGE) showed that bacterial communities shifted both in response to farm loading and its cessation. A seasonal effect on microbial communities was also evident. Although bacterial communities did shift again during the fallowing period, this shift was not necessarily a return to preloading communities. The complexity of community shifts may be affected by the vast functional redundancy of bacterial groups. All bacterial communities, including those at reference sites, were highly dynamic. Respiration studies of amended sediments indicated that fish farm sediments were at least as resilient and diverse as reference site communities. The results of this study indicate that the functional redundancy of highly complex bacterial communities contributes to their robustness. The relationship between diversity and stability in bacterial communities remains unclear and requires further investigation before an understanding of bacterial response to perturbation is possible.
X‐ray absorption spectroscopy (XAS) of toxic metal mineral transformations by fungi
Authors: Fomina Marina , Charnock John , Bowen Andrew D. , Gadd Geoffrey M.
Published: September 2006

Fungi can be highly efficient biogeochemical agents and accumulators of soluble and particulate forms of metals. This work aims to understand some of the physico‐chemical mechanisms involved in toxic metal transformations focusing on the speciation of metals accumulated by fungi and mycorrhizal associations. The amorphous state or poor crystallinity of metal complexes within biomass and relatively low metal concentrations make the determination of metal speciation in biological systems a challenging problem but this can be overcome by using synchrotron‐based element‐specific X‐ray absorption spectroscopy (XAS) techniques. In this research, we have exposed fungi and ectomycorrhizas to a variety of copper‐, zinc‐ and lead‐containing minerals. X‐ray absorption spectroscopy studies revealed that oxygen ligands (phosphate, carboxylate) played a major role in toxic metal coordination within the fungal and ectomycorrhizal biomass during the accumulation of mobilized toxic metals. Coordination of toxic metals within biomass depended on the fungal species, initial mineral composition, the nitrogen source, and the physiological state/age of the fungal mycelium.
SEMI‐MECHANISTIC MODELLING IN NONLINEAR REGRESSION: A CASE STUDY
Authors: Domijan Katarina , Jorgensen Murray , Reid Jeff
Published: September 2006

This paper discusses the use of highly parameterized semi‐mechanistic nonlinear models with particular reference to the PARJIB crop response model of Reid (2002)[Yield response to nutrient supply across a wide range of conditions 1. Model derivation. Field Crops Research77, 161–171]. Compared to empirical linear approaches, such models promise improved generality of application but present considerable challenges for estimation. Some success has been achieved with a fitting approach that uses a Levenberg–Marquardt algorithm starting from initial values determined by a genetic algorithm. Attention must be paid, however, to correlations between parameter estimates and an approach is described to identify these based on large simulated datasets. This work illustrates the value for the scientist in exploring the correlation structure in mechanistic or semi‐mechanistic models. Such information might be used to reappraise the structure of the model itself, especially if the experimental evidence is not strong enough to allow estimation of a parameter free of assumptions about the values of others. Thus statistical modelling and analysis can complement mechanistic studies, making more explicit what is known and what is not known about the processes being modelled and guiding further research.
Fixed-Effects Methods for the Analysis of Nonrepeated Events
Authors: Allison Paul D. , Christakis Nicholas A.
Published: September 2006

For repeated events, fixed-effects regression methods—which control for all stable covariates—can be implemented by doing Cox regression with stratification on individuals. For nonrepeated events, we consider the use of conditional logistic regression to estimate fixed-effects models with discrete-time data. Known in the epidemiological literature as the case-crossover design, this method fails when any covariate is a monotonic function of time. Hence, no control for time itself can be included, leading to potentially spurious estimates. As an alternative, we consider the case-time-control method for estimating the effect of a dichotomous predictor. This method allows for the introduction of a control for time by reversing the role of the dependent and independent variables. In contrast to earlier work, we show that the method can be applied to data that contain only uncensored cases, and that it is possible to control for additional covariates, both categorical and quantitative. Simulation studies indicate that the case-time-control method is substantially superior to the case-crossover method and to conventional logistic regression. The methods are illustrated by estimating the effect of a wife's death on the hazard of death for her husband.
Do Conditional Benefits Reduce Equilibrium Unemployment?
Authors: Van DerPLOEG FREDERICK
Published: September 2006

Although unconditional unemployment benefits destroy jobs in competitive and noncompetitive labor markets, conditional benefits can spur job growth in noncompetitive labor markets. Unconditional benefits reduce the penalty of shirking and misconduct, while conditional benefits increase this penalty. This is shown for the efficiency‐wage, no‐shirking model of the labor market developed by Shapiro and Stiglitz (1984). Switching from unconditional to conditional benefits lowers unemployment. Tough eligibility requirements are thus important components of the welfare state. However, if conditional benefits are financed by a payroll tax, conditional benefits exert upward wage pressure so that unemployment falls by less and may even increase.
Tax Reform with Useful Public Expenditures
Authors: CASSOU STEVEN P. , LANSING KEVIN J.
Published: September 2006

We examine the effects of tax reform in an endogenous growth with two types of useful public expenditures. The optimal fiscal policy shifts the tax base to private consumption and generally requires a change in the size of government. If a tax reform holds the size of government fixed to satisfy a revenue‐neutrality constraint, then the reform will be suboptimal; theory alone cannot tell us if welfare will be improved. For some model calibrations, we find that a revenue‐neutral consumption tax reform can result in large welfare gains. For other quite plausible calibrations, the exact same reform can result in tiny or even negative welfare gains as the revenue‐neutrality constraint becomes more severely binding. Overall, our results highlight the uncertainty surrounding the potential welfare benefits of fundamental tax reform.
Wiener–Kolmogorov Filtering and Smoothing for Multivariate Series With State–Space Structure
Authors: Gómez Víctor
Published: September 2006

Abstract.  Wiener–Kolmogorov filtering and smoothing usually deal with projection problems for stochastic processes that are observed over semi‐infinite and doubly infinite intervals. For multivariate stationary series, there exist closed formulae based on covariance generating functions that were first given independently by N. Wiener and A.N. Kolmogorov around 1940. In this article, we consider multivariate series with a state–space structure and, using a new purely algebraic approach to the problem, we prove the equivalence between Wiener–Kolmogorov filtering and Kalman filtering. Up to now, this equivalence has only been partially shown. In addition, we get some new recursions for smoothing and some new recursions to compute the filter weights and the covariance generating functions of the errors. The results are extended to nonstationary series.
Vitamin E: the radical protector
Authors: Wolf Ronni , Wolf Danny , Ruocco Vincenzo
Published: September 2006

Since its discovery and isolation the importance of vitamin E in maintaining normal physiologic processes and its value in treating various disease states have been the subject of much controversy. It was our intention to review and highlight some of the arguments and problems regarding the usefulness of vitamin E and to try to put them into proper perspective. The major area of interest concerning vitamin E lies essentially in its role in preventing damage caused by free radicals. The latter are now known to play an important role in radiation induced carcinogenesis, photoaging and photosensitization. The chemistry of vitamin E, its physiological function as a major antioxidant and its interaction with other antioxidants are described by the sum of animal studies, in vitro research and epidemiological investigations. In preparing the current data, it appeared that despite the controversy and conflicting results the body of literature as a whole judges vitamin E to be useful as an antioxidant. Although, in principle, the use of vitamin E can be quite advantageous, the manner of its administration, especially regarding topical application, remains unclear.
Calcipotriol improves the efficacy of cyclosporine in the treatment of psoriasis vulgaris
Authors: Kokelj Franco , Torsello Pierpaolo , Plozzer Carmela
Published: September 2006

Objective

The aim of this study was to evaluate the efficacy and tolerability of the association of calcipotriol ointment (50 μg/g) plus cyclosporine versus cyclosporine alone in the treatment of moderate psoriasis (mean PASI: 13).

Methods

Twenty patients were enrolled in this right‐left open study. All the patients admitted were treated with cylosporine at an initial dose of 4.5 mg/kg/day; in case of clinical improvement this dosage was reduced by 0.5 mg/kg/day every 15 days. In each patient we chose two similar, symmetrical lesions and calcipotriol ointment was applied only on the right lesion, twice a day, until the healing of the lesion or for 1 month. Patients were checked at baseline and every 15 days.

Results

Eighteen patients completed the study and 17 of the 18 presented more evident improvement on the side treated with combined therapy, while only one patient showed a better result on the side treated with cyclosporine alone. A significant difference of the total score was already present after 15 days of therapy and was confirmed at the following check‐ups.

Conclusions

These results underline the usefulness of the association of calcipotriol and cyclosporine in order to decrease the total dosage of cyclosporine.
Plasma concentrations of IFN‐γ and TNF‐α: in psoriatic patients before and after local treatment with dithranol ointment
Authors: Chodorowska Grazyna
Published: September 2006

IFN‐γ and TNF‐α plasma levels were measured before and after local treatment in 27 patients. Twenty healthy subjects served as controls. Plasma concentrations of IFN‐γ and TNF‐α were significantly higher before treatment (178.7 ± 11.9 pg/ml and 31.9 ± 11.6 pg/ml, respectively) compared to the control group (139.6 ± 7.86 pg/ml and 17.1 ± 7.7 pg/ml, respectively). After treatment IFN‐γ levels were significantly decreased (151.3 ± 8.3 pg/ml) toward the control group values and TNF‐α levels were observed even lower than in the controls (11.48 ± 6.8 pg/ml). No correlations were found between age, duration of psoriasis and plasma levels of cytokines. However, IFN‐γ levels were related, although not significantly, to disease severity (evidenced by the PASI score). The data support the important proinflammatory role of IFN‐γ and TNF‐α in the clinical manifestation of psoriasis. © 1998 Elsevier Science B.V.
Childhood cutaneous mucinosis
Authors: Velho Glória C. , Oliveira Manuela , Alves Rosário , Silvestre Frederico , Massa António , Baptista A. Poiares
Published: September 2006

A case of childhood cutaneous mucinosis is described. This is a clinical condition that is rarely seen and has only recently been included in the group of primary mucinosis.
Sclerosing sweat duct carcinoma mimicking dermatofibroma
Authors: González‐Güemes M. , Yanguas I. , Goday J.J. , Lozano M. , Soloeta R.
Published: September 2006

Sclerosing sweat duct carcinoma is an infrequent adnexal tumor, locally aggressive and with a high incidence of local recurrences. Its location is preferably cephalic and its clinical presentation often unspecific. We present a new case with an atypical location and the clinical appearance of a benign cutaneous lesion. Diagnosis was established after a histological and immunohistochemical study. A terminological review was done.
Balneophototherapy in small plaque parapsoriasis ‐ four case reports
Authors: Gambichler Thilo , Manke‐Heimann Antje
Published: September 2006

Four patients suffering from small plaque parapsoriasis were treated successfully with balneophototherapy. Within 4 weeks salt‐water baths and UV irradiation resulted in clinical clearing of more than 90% of lesions with a duration of total clinical response between 8 and 12 weeks without further maintenance treatment.
Leishmaniasis of glans penis
Authors: Schubach A. , Cuzzi‐Maya T. , Gonçalves‐Costa S.C. , Pirmez C. , Oliveira‐Neto M.P.
Published: September 2006

Background

Leishmaniasis is an important protozoan disease. In the Americas it is produced by several species of the genus Leishmania, transmitted by sand flies of the genus Lutzomyia. Disease spectrum ranges from cutaneous ulceration to more serious involvement of oronasal mucosa that may progress to destruction of central structures of the face and to the life‐threatening visceral forms. Leishmania Viannia braziliensis is the most widespread species in Brazil and is often associated with mucosal involvement. Cutaneous lesions are commonly localised in uncovered areas of the body. Genital lesions are rare.

Materials and methods

A patient with an ulcerated lesion of the glans penis, followed subsequently by mucosal lesions of the nasal cavity and palate, is presented. Diagnostic procedures were: leishmanin skin test (Montenegro's test) and biopsy of the ulcer border processed for histopathological examination and culture in NNN medium.

Results

Leishmanin skin test was positive. Histopathology showed a granulomatous infiltrate containing some parasites. Culture was positive for Leishmania sp., and was later identified by zymodeme analysis and monoclonal antibodies as L.(V.)braziliensis. The patient was treated with pentavalent antimony at the dose of 10 (mg/kg)/day for 30 days and the lesions healed.

Comments and conclusions

In men, especially over 50 years of age, ulceration of the glans penis is highly suggestive of carcinoma. Precise differential diagnosis is imperative. A lesion, such as the one reported, may cause diagnostic difficulties when it presents in countries different from the source, where the condition is very uncommon. This is increasingly frequent in the current era of widespread air travel.
Anaerobic bacteria in men with urethritis
Authors: Mazuecos J. , Aznar J. , Rodriguez‐Pichardo A. , Marmesat F. , Borobio M.V. , Perea E.J. , Camacho F.
Published: September 2006

Aim

Investigation of the urethral flora in men with urethritis, with particular reference to anaerobic bacteria.

Methods

Multiple cultures were performed on three urethral samples from 110 men attending the STD Clinic of the School of Medicine in Seville: 35 with no evidence of urethritis (control group), and 75 with urethritis (17 gonococcal urethritis (GU) and 58 non‐gonococcal urethritis (NGU)). In the 58 men with NGU, Chlamydia trachomatis was isolated in 16 (27.5%), Ureaplasma urealyticum in 18 (31%), Trichomonas vaginalis in two (3.4%) and no pathogens were isolated in the remaining 22 (38%) patients.

Results

Aerobic flora, mainly Staphylococcus spp., were isolated less frequently (41%) in patients with GU than in the control group (80%), and those with NGU (72%). Anaerobic flora were isolated in 62% of patients, with similar isolation rates in each group. Gram‐negative anaerobes were more frequently isolated in men with urethritis, especially NGU, compared to controls (P < 0.05). Prevotella spp. and Bacteroides spp. were significantly more frequently isolated in patients with NGU, including Chlamydia‐negative NGU. Fusobacterium spp. were more frequent in the Chlamydia‐ positwe NGU than in the controls (P < 0.05). P. magnus was the most frequent anaerobic species found in the control group, while P. prevotii was most frequently seen in the urethritis group. B. ureolyticus, P. prevotii and P. tetradius were more frequent on the NGU group (P < 0.05). B. ureolyticus was commoner in patients with Chlamydia‐ negalive NGU, while P. tetradius and P. asaccharolytica was commoner in those where C. trachomatis was isolated than in the control group.

Conclusion

Urethral microflora isolated showed ten bacterial genus and 25 different species of anaerobes. The spectrum of these microflora changed with the presence of urethritis and varied with its aetiology.
A case of coumarin necrosis with penile and pedal involvement
Authors: Harmanyeri Yavuz , Taşkapan Oktay , Doǧlan Bilal , Baloǧlu Hüseyin , Başak Mesut
Published: September 2006

A 57‐year‐old male patient with advanced adenocarcinoma of the lung, who was administered oral anticoagulant therapy because of pulmonary embolism, developed coumarin necrosis confined to the penis and feet. To our knowledge, this patient showing acral involvement is the seventh case of coumarin‐induced penile necrosis reported to date.
Idiopathic plantar hidradenitis
Authors: Bártolo Elvira , Anes Isabel , Capitão‐Mor Manuela , Brandão Francisco M.
Published: September 2006

We describe four cases of idiopathic plantar hidradenitis (IPH), a form of neutrophilic eccrine hidradenitis (NEH) localized on the feet of otherwise healthy young persons. Our patients were all males, 8–17 years old, in apparently good health, but presenting erythematous painful papules, plaques and nodules on the soles. They were afebrile and there were no constitutional symptoms. The differential diagnoses included erythema nodosum, vasculitis and traumatic plantar urticaria. The histological features of IPH are similar to those of NEH, except for the absence of syringosquamous metaplasia. The patients were treated with topical steroids and oral NSAID, with total resolution of the lesions in 1 or 2 weeks.
Palmar spiny keratoderma associated with type IV hyperlipoproteinemia
Authors: Urbani Carlo Enrico , Moneghini Laura
Published: September 2006

We report the case of a 35‐year‐old man with acquired palmar spiny keratoderma (SK) in association with type IV hyperlipoproteinemia. Cutaneous lesions appeared 11 years before with no history of any previous skin conditions, topical medication or systemic treatment with Vitamin A‐derived drugs, x‐irradiation, arsenic poisoning or prolonged sun exposure. Family aggregation for SK or other disorders of keratinization was ruled out. Blood chemistries demonstrated hypertriglyceridemia (422 mg/dl) and elevation in plasma concentration of the pre‐β fraction (VLDL) of lipoproteins pattern compatible with a type IV hyperlipoproteinemia. Family aggregation for this metabolic defect was then confirmed. The histologic hallmark of the ‘spine’ lesion was a compact column of hyperparakeratotic cells (columnar hyperparakeratosis) continuous with a hypogranular layer, without further evidence of dyskeratotic or vacuolated keratinocytes and inflammatory cells in the corresponding dermis. SK represents a well‐definite entity which fulfills precise clinico‐histologic criteria. However, three main questions are related to SK: differential diagnosis with porokeratosis on histologic examination (columnar hyperparakeratosis or hyperorthokeratosis alone in SK vs. cornoid lamella accompanied by remarkable dermoepidermal changes in porokeratosis); classificative scheme (proper nomenclature to avoid misleading and confounding names); and nosological arrangement (probably two subsets exist: hereditary or benign; and acquired, or idiopathic, which may be paraneoplastic in about 50% of the patients). To the best of our knowledge this is the first case reporting the association between SK and a metabolic impairment although the real connections linking these conditions are still unclear.
Verrucoid cutaneous rhinosporidiosis
Authors: Ghorpade Ashok , Ramanan Cherukot
Published: September 2006

Verruca vulgaris like lesions of cutaneous rhinosporidiosis are reported in a middle aged Indian male. He also had nasal rhinosporidiosis. Imprint smears from skin lesions showed sporangia with endospores, confirming the diagnosis.
Cutaneous larva migrans associated with water shoe use
Authors: Swanson Jason R. , Melton Jeffrey L.
Published: September 2006

It has been long suspected that footwear is protective against cutaneous larva migrans. This case report describes a woman who developed cutaneous larva migrans despite wearing ‘protective’ footwear. We forward a hypothesis by which recently popular water shoes may actually be conducive to the development of cutaneous larva migrans rather than having a protective function.