bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherence length of the KY(WO4)2 single crystal
Authors: Shalimov A. , Borowiec M. T. , Zayarnyuk T. , Pujol M. C. , Aguiló M. , Díaz F.
Published: May 2008

Potassium yttrium tungstate is a monoclinic crystal with space group C2/c. The specific X-ray investigations presented in this article determine the coherence scattering length for this crystal. The scattering profiles were obtained using a Philips MRD X-ray diffractometer. The Williamson–Hall method was used to determine the coherence scattering length and internal stresses.
Monitoring structural transformations in crystals. 12. Course of an intramolecular [4 + 4] photocycloaddition in a crystal
Authors: Trzop Elżbieta , Turowska-Tyrk Ilona
Published: May 2008

Variations in crystal and molecular structures, brought about by the intramolecular [4 + 4] photocycloaddition of bi(anthracene-9,10-dimethylene), were monitored using X-ray diffraction. The cell volume increased by 0.8% until the reaction was ca 40% complete, and afterwards decreased by 1.6% during the remainder of the photoreaction. The changes of the a and b lattice parameters were correlated with the changes of the molecular shape and packing. The distance between the directly reacting C atoms varied in a manner not observed for other photochemical reactions in crystals. It was constant until ca 20% photoreaction progress, then decreased, and later stabilized from ca 40% photoreaction progress. This phenomenon was explained by interplay between stress resulting from the presence of product molecules and the rigidity of reactant molecules. Changes of the orientation of molecules during the photoreaction were smaller than in the case of other monitored photochemical reactions in crystals owing to similarities in the shape and packing of reactant and product molecules. Weak C—H...π hydrogen bonds exist among reactant molecules in the pure reactant and partly reacted crystals.
Orientational disorder in crystals of (NH4)3MoO3F3 and (NH4)3WO3F3
Authors: Udovenko A. A. , Laptash N. M.
Published: May 2008

Triammonium trioxotrifluoromolybdate (NH4)3MoO3F3 (I) and trioxotrifluorotungstate (NH4)3WO3F3 (II) were synthesized in a single-crystal form and their structures were refined by X-ray diffraction. These two isostructural compounds belong to the elpasolite-type structure (cubic system, space group Fm3m, Z = 4). O and F atoms are randomly distributed in two independent positions [24(e) and 96(j)] of the cubic unit cell, and the central atoms and the ammonium cation containing N2 are shifted from the symmetry centers into the 32(f) position. As a consequence, O and F atoms in the equilibrium structure were identified on a local scale by the metal–ligand distance and hydrogen atomic coordinates of the disordered ammonium cation N2H4 were determined. The slightly compressed MX
6 (M = Mo, W; X = O, F) octahedron has a fac configuration with the central atom shifted toward the face occupied by three O atoms. The true geometry of this polyhedron permits us to explain the observed vibrational spectra of the compounds examined and to eliminate the contradiction in interpretation of the vibrational spectra of [MO3F3]
n− species reported in the literature. Both complexes reveal a dynamic disordering: the [MX
6]3− anions are disordered on 48 equivalent orientations and the N2H4 groups have eight orientations.
Solid-state structures of the covalent hydrides germane and stannane
Authors: Maley Iain J. , Brown Daniel H. , Ibberson Richard M. , Pulham Colin R.
Published: May 2008

The low-temperature crystal structures of perdeuterogermane (m.p. 108 K) and perdeuterostannane (m.p. 123 K) are reported. The structures have been characterized from low-temperature (5 K) high-resolution neutron powder diffraction experiments following sample preparation using in situ gas-condensation techniques. GeD4 crystallizes in an orthorhombic structure, space group P212121, with one molecule in the asymmetric unit, and with an average Ge—D bond length of 1.517 (3) Å. The SnD4 structure is monoclinic (space group C2/c), and the molecule is located on a twofold rotation axis with an average Sn—D bond length of 1.706 (3) Å. The crystal structures are discussed in relation to those of other tetrahedral molecules of group IV hydrides at low temperature, and evidence is presented that the crystal structure of silane, below 38 K, is isostructural with germane.
On the crystal chemistry of olivine-type germanate compounds, Ca1 + x

M
1 − x
GeO4 (M
2+ = Ca, Mg, Co, Mn)
Authors: Redhammer Günther J. , Roth Georg , Amthauer Georg , Lottermoser Werner
Published: May 2008

Germanate compounds, CaMGeO4 with M
2+ = Ca, Mg, Co and Mn, were synthesized as single crystals by slow cooling from the melt or by flux growth techniques. All the compositions investigated exhibit Pnma symmetry at 298 K and adopt the olivine structure. The M2 site is exclusively occupied by Ca2+, while on M1 both Ca2+ and M
2+ cations are found. The amount of Ca2+ on M1 increases with the size of the M1 cation, with the smallest amount in the Mg compound (0.1 atoms per formula unit) and the largest in the Mn compound (0.20 atoms per formula unit), while in Ca2GeO4, also with olivine structure, both sites are completely filled with Ca2+. When compared with those of Ca silicate olivine, the lattice parameters a and c are distinctly larger in the analogous germanate compounds, while b has essentially the same values, regardless of the tetrahedral cation, meaning that b is independent of the tetrahedral cation. Structural variations on the octahedrally coordinated M1 site are largely determined by the size of the M1 cation, the average M1—O bond lengths being identical in Ca silicate and Ca germanate olivine. Increasing the size of the M1 cation induces an increasing polyhedral distortion, expressed by the parameters bond-length distortion, octahedral angle variance and octahedral quadratic elongation. However, the Ca germanate olivine compounds generally have more regular octahedra than the analogous silicates. The octahedrally coordinated M2 site does not exhibit large variations in structural parameters as a consequence of the constant chemical composition; the same is valid for the tetrahedral site.
An expanded Transactional Stress and Coping Model for siblings of children with sickle cell disease: family functioning and sibling coping, self‐efficacy and perceived social support
Authors: Gold J. I. , Treadwell M. , Weissman L. , Vichinsky E.
Published: May 2008

Aim  To investigate the application of an expanded Transactional Stress and Coping Model for the psychological adjustment of non‐chronically ill, African‐American siblings of children with sickle cell disease (SCD).

Methods  Ninety‐seven siblings (M = 11.24 years) from 65 families who care for a child with SCD participated. Primary caregivers completed the Coping Health Inventory for Parents, the Family Relations Scale and the Child Behaviour Checklist, while siblings completed the Kidcope, the Children's Self‐Efficacy for Peer Interaction Scale, and the Social Support Scale for Children.

Results  Family processes were predictive of sibling adjustment, revealing that family coping, expressiveness and support improved adjustment, while family conflict predicted poor adjustment.

Conclusion  Findings suggest that family‐centered interventions stressing family expressiveness and support, while minimizing conflict, will contribute to sibling psychological adjustment.
Children from low‐income families have less access to sports facilities, but are no less physically active: cross‐sectional study (EarlyBird 35)
Authors: Voss L. D. , Hosking J. , Metcalf B. S. , Jeffery A. N. , Wilkin T. J.
Published: May 2008

Background  Rising levels of childhood obesity have led to an increasing number of Government sponsored initiatives attempting to stem the problem. Much of the focus to date has been on physical activity and out‐of‐school activity in particular. There is an assumption that children from low‐income families suffer most where there is a lack of structured physical education in school. Accordingly, provision of additional facilities for sport and other forms of active recreation tend to target areas of socio‐economic deprivation.

Aim  We have assessed the relationship between parental income, the use of out‐of‐school sports facilities and the overall physical activity of young children across a wide socio‐economic range.

Methods  Total weekly physical activity was measured, objectively, over 7 days both at 7 years and 8 years in a healthy cohort of 121 boys and 93 girls using actigraph accelerometers. Questionnaires were used to establish parental income and parents reported the child's weekly use of out‐of‐school facilities for structured physical activity.

Results  Children from low‐income families attended significantly fewer sessions of structured out‐of‐school activities than those from wealthier families (r = 0.39), with a clear dose‐response relationship across income groups. Nevertheless, total physical activity, measured objectively over seven continuous days, showed no relationship between parental income and the mean activity level of the children (r = −0.08). Nor did we find a relationship between parental income and time spent in higher intensity activity (r = −0.04).

Conclusion  Social inequality appears to have little impact on physical activity in young children. Those from poorer families make less use of facilities for structured activity out‐of‐school but they nevertheless record the same overall level of activity as others. What they lack in opportunity they appear to make up in the form of unstructured exercise. Improving provision for sport may not lead to the expected rise in activity levels in young children.
Factors associated with bed sharing and sleep position in Thai neonates
Authors: Anuntaseree W. , Mo‐suwan L. , Vasiknanonte P. , Kuasirikul S. , Ma‐a‐lee A. , Choprapawon C.
Published: May 2008

Background  Sleep in a supine position and in a bed separate from but proximate to adults is recommended, in several Western countries, to prevent Sudden Infant Death Syndrome (SIDS). Cultural differences and a lower rate of SIDS in Asian populations may affect concern with this problem and thus infant sleeping arrangements.

Objective  To study bed sharing and sleep position in Thai neonates and the relationship to infant and maternal characteristics.

Methods  A cross‐sectional survey based on interviews with parents of infants aged 21 days old, was conducted under the Prospective Cohort Study of Thai Children.

Results  Of the total sample, 2236/3692 (60.6%) infants shared a bed with their parents. Sixty per cent of the parents placed their infants to sleep in a supine position, 32.2% on their side and 4.9% in a prone position. Bed sharing was associated with older maternal age, higher education, Muslim mother, and with work status of professional career or unemployed. Placing the infants to sleep in a prone position was associated with infant birth weight of greater than 2500 g, older maternal age, higher education, Buddhist mother, mother with professional career and middle‐class household economic status.

Conclusions  Infant bed sharing is a common practice in the Thai culture, as in other Asian countries. The prone sleep position is less common than in Western populations. The main factor associated with both bed sharing and putting infants to sleep in the prone position was a higher maternal socioeconomic status (SES), in contrast to previous studies in some Western countries in which both practices were associated with low maternal SES. Cultural differences may play an important role in these different findings.
Impact of turbulence on riverine zooplankton: a mesocosm experiment
Authors: SLUSS TAMARA D. , COBBS GARY A. , THORP JAMES H.
Published: May 2008

1. With increases in river discharge over time and space, zooplankton generally encounter increased turbulence, turbidity, hydraulic forces, downstream advection and food limitations, all of which should affect species diversity and densities. Of these factors, the role of turbulence on the distribution of zooplankton is least known along longitudinal and lateral dimensions in river networks.

2. We tested the factorial effects of turbulence and grazing level on Ohio River potamoplankton in spring and summer using twelve 1600‐L, outdoor mesocosms. Turbulence was calculated using the Froude number for equal depths but with current velocities of 0.064 and 0.32 m s−1. Grazing levels corresponded to a high density treatment (=ambient river densities of rotifers, copepods and cladocerans) and a low density treatment (initially no zooplankton >64 μm). All tanks had the same water residence time, and hydraulic stress was minimized by circular flow patterns.

3. Zooplankton densities and population growth rates were significantly affected by turbulence level and season. In general, rotifer populations grew faster in high turbulence tanks (though Keratella and Brachionus populations flourished in both treatments in summer) and microcrustaceans thrived better in low turbulence environments. The larger, calanoid copepods handled more turbulent conditions much better than cyclopoids or nauplii. Zooplankton had no detectable effects on particulate organic carbon concentrations in either month (values were higher in spring), but rotifers reduced chlorophyll concentrations in both months.

4. The relative importance of turbulence in controlling potamoplankton is probably to vary not only on a longitudinal basis in river networks but also with both the hydrogeomorphic complexity of river reaches and the type and amount of river regulation. Plans for river rehabilitation and management should incorporate non‐turbulent habitats in large rivers as a means of enhancing zooplankton populations and providing an important food web component for planktivores.
Milk‐production potential of different sward types in a temperate southern Australian environment
Authors: Chapman D. F. , Tharmaraj J. , Nie Z. N.
Published: May 2008

The milk‐production potential of different sward types was measured in each of the four seasons of the year in a replicated experiment in south‐west Victoria, Australia. Dairy cows were offered ad libitum allowances of a ‘short‐term winter’ sward, based on Italian ryegrass (treatment STW), a ‘long‐term winter’ sward, based on a winter‐active tall fescue (treatment LTW), a ‘long‐term summer’ sward, based on a summer‐active tall fescue (treatment LTS) and a Control sward (perennial ryegrass) in four seasons (days in milk in parentheses): spring (November dairy cows, 124), summer (February, 227), autumn (May, 234) and winter (August, sixty‐four). A ‘short‐term summer’ sward, based on chicory and white clover (treatment STS), was also included in summer. There was a significant season × treatment interaction caused by a more gradual decline in milk yield from peak for cows grazing treatment LTS compared to the Control treatment in the transition period from spring to summer. In summer, cows grazing treatment STS produced more milk (1·41 kg fat plus protein per cow d−1) than cows grazing all other treatments (0·92 kg per cow d−1) because of the superior nutritive value of herbage of pre‐grazing pasture and higher apparent dry‐matter intakes. Swards based on alternative species to perennial ryegrass are capable of supporting milk production that is at least comparable over an annual cycle.
Effect of frequency of application of inorganic nitrogen fertilizer within a rotational paddock‐grazing system on the performance of dairy cows and inputs of labour
Authors: Ferris C. P. , Patterson D. C. , McCoy M. A.
Published: May 2008

As herd sizes and labour costs increase, and the availability of skilled labour decreases, efficient use of available labour becomes more important in dairy cow systems. Two experiments were conducted to examine the effect of reducing the frequency of application of inorganic nitrogen (N) fertilizer on inputs of labour and performance of dairy cows. Experiments 1 (duration of 169 d) and 2 (duration of 179 d) involved fifty‐eight and forty multiparous Holstein–Friesian dairy cows, respectively, in mid‐lactation. In each experiment, in the ‘infrequent’ treatment fertilizer was applied to all paddocks on a single occasion at the start of each grazing cycle, while in treatment ‘frequent’, fertilizer was applied on three occasions each week, within 2 or 3 d of each paddock having been grazed. The experimental treatments were started from 30 March and 29 March in Experiments 1 and 2 respectively. Total N application rates were approximately 360 and 250 kg N ha−1 in Experiments 1 and 2 respectively. Concentrate feed (4·0 kg per cow) was offered daily in both experiments. With the ‘infrequent’ treatment, highest concentrations of crude protein and nitrate in herbage were observed in swards grazed approximately 10 d after N fertilizer was applied. Treatment had no significant effect on milk yield, milk fat and protein concentrations, and final live weight and body condition score of cows in either experiment. Milk urea and plasma urea concentrations were not significantly affected by treatment. Calculated application times of fertilizer for a herd of 100 dairy cows were 107 and 83 min week−1 for the ‘frequent’ and ‘infrequent’ treatments respectively.
Sensory aroma from Maillard reaction of individual and combinations of amino acids with glucose in acidic conditions
Authors: Wong Kam Huey , Abdul Aziz Suraini , Mohamed Suhaila
Published: May 2008

The aroma produced in glucose–amino acids (individual and in combination) Maillard reaction, under acidic conditions at 100 °C were determined and compared by trained panellist. Proline produced pleasant, flowery and fragrant aroma. Phenylalanine and tyrosine produced dried roses aroma. Alanine produced fruity and flowery odour, while aspartic acid and serine both produced pleasant, fruity aroma. Arginine, produced a pleasant, fruity and sour aroma at pH 5.2, but not at its natural pH. Glycine, lysine, threonine and valine produced a pleasant caramel‐like odour. Isoleucine and leucine gave off a burnt caramel aroma. Methionine developed a fried potato odour. Cysteine and methionine produced savoury, meaty and soy sauce‐like flavours. A combination of these amino acids produced different types of aroma, with the stronger note dominating the odour of the mixture. This study will help the prediction of flavour characteristics of hydrolysates from different protein sources.
The efficacy of reflexology: systematic review
Authors: Wang Mei‐Yeh , Tsai Pei‐Shan , Lee Pi‐Hsia , Chang Wen‐Yin , Yang Che‐Ming
Published: May 2008

Title.  The efficacy of reflexology: systematic review.

Aim.  This paper is a report of a systematic review to evaluate the efficacy of reflexology in any condition.

Background.  Anecdotal evidence has shown potential benefits of reflexology in a variety of health conditions. However, the efficacy of reflexology has yet to be determined.

Data sources.  Cochrane library, PubMed, MEDLINE, EBM review, ProQuest Medical Bundle and SCOPUS databases were searched using the following medical subject headings or key words: reflexology, foot reflexotherapy, reflexological treatment, foot massage and zone therapy. Chinese articles were searched through the Chinese electronic periodical services and Wangfane database. The publication date was limited from 1996 to 2007.

Review methods.  Studies were selected if they were written in English or Chinese, used a controlled clinical trial design, used reflexology as a stand‐alone modality, and reported such outcomes as symptoms relief, quality of life and patients’ perceptions of reflexology. Study quality was reviewed based on the evidence rating system of the United States Preventive Services Task Force, and studies with the evidence rating of II‐2 fair or above were included in this review.

Results.  Among the five studies suitable for review, there was only one report of a statistically significant treatment effect. Among the 12 outcome variables examined, the treatment effect size for urinary symptoms was large, whereas the effect size for other conditions was negligible.

Conclusion.  There is no evidence for any specific effect of reflexology in any conditions, with the exception of urinary symptoms associated with multiple sclerosis. Routine provision of reflexology is therefore not recommended.
Child health promotion in the United Kingdom: does health visitors’ practice follow policy?
Authors: Condon Louise
Published: May 2008

Title.  Child health promotion in the United Kingdom: does health visitors’ practice follow policy?

Aim.  This paper is a report of a study to assess to what extent national child health promotion policy is reflected in health visitors’ practice across the United Kingdom.

Background.  Community or public health nurses are often key providers of child health promotion programmes for well children. Over the last decade, national United Kingdom policy concerning universal preventive health services for preschool children has changed rapidly. Health promotion contacts are increasingly targeted to those with the highest health needs.

Method.  A survey was conducted in 2005 of health visitors’ Child Health Promotion Programme practice. A postal questionnaire exploring local practice and policy was sent to a random 10% sample of Registered Health Visitors. Respondents were from all four countries of the UK although predominantly (90%) from England. Nominal data were analysed by frequencies and associations between key variables. The chi‐square test was used for comparisons between groups of respondents, with a statistical significance level of P < 0·05.

Findings.  A 64% response rate (n = 1537) was obtained, with 1043 questionnaires from current practitioners. While three‐quarters of respondents stated that the number of routine contacts recommended in local policy had decreased since revision of the Child Health Promotion Programme, 39% stated that targeted contacts had increased. Just over a third agreed that contact should be targeted to children with identified needs after 1 year of age.

Conclusion.  As child health promotion programmes play a major part in well‐child care internationally, it is important to take into account diversity in practice, and potential conflicts between professional values and policy.
Work‐home interference among nurses: reciprocal relationships with job demands and health
Authors: Van Der Heijden Beatrice I.J.M. , Demerouti Evangelia , Bakker Arnold B. ,   The NEXT Study Group coordinated by Hans‐Martin Hasselhorn
Published: May 2008

Title.  Work‐home interference among nurses: reciprocal relationships with job demands and health.

Aims.  This paper is a report of a study with three aims: (i) to investigate whether emotional, quantitative and physical demands have a causal, negative impact on nurses’ health; (ii) to examine whether work‐home interference can explain this effect, by playing a mediating role; and (iii) to test the so‐called loss spiral hypothesis claiming that nurses’ health problems lead to even higher job demands and more work‐home interference over time.

Background.  While many scholars have thought in terms of the stressor→work‐home interference→strain model, the validity of a model that includes opposite pathways needs to be tested.

Method.  A questionnaire was completed twice, with a 1‐year time interval by 753 (63·4%) Registered Nurses working in hospitals, 183 (15·4%) working in nursing homes, and 251 (21·1%) working in home care institutions. The first measurement took place between October 2002 and June 2003.

Findings.  Our findings strongly support the idea of cross‐lagged, reciprocal relationships between job demands and general health over time. The reciprocal model with work‐home interference as an intervening variable (including reciprocal relationships between job demands, work‐home interference and general health) showed a good fit to the data, and proved to be superior to both the causality and reversed causation models.

Conclusion.  The higher nurses’ job demands, the higher is their level of work‐home interference and the more likely is a general health deterioration over time, in turn giving rise to higher job demands and work‐home interference, which may even aggravate the nurses’ general health, and so on.
Can home visits help reduce hospital readmissions? Randomized controlled trial
Authors: Wong Frances Kam Yuet , Chow Susan , Chung Loretta , Chang Katherine , Chan Tony , Lee Wai‐Man , Lee Rance
Published: May 2008

Title.  Can home visits help reduce hospital readmissions? Randomized controlled trial

Aim.  This paper is a report of a study to determine whether home visits can reduce hospital readmissions.

Background.  The phenomenon of hospital readmission raises concerns about the quality of care and appropriate use of resources. Home visits after hospital discharge have been introduced to help reduce hospital readmission rates, but the results have not been conclusive.

Method.  A randomized controlled trial was carried out from 2003 to 2005 . The control group (n = 166) received routine care and the study group (n = 166) received home visits from community nurses within 30 days of hospital discharge. Data were collected at baseline before discharge and 30 days after discharge.

Findings.  Patients in the study group were statistically significantly more satisfied with their care. There were no statistically significant differences in other outcomes, including readmission rate, ADL score, self‐perceived life satisfaction and self‐perceived health. Regression analysis revealed that self‐perceived life satisfaction, self‐perceived health and disease category other than general symptoms were three statistically significant variables predicting hospital readmissions.

Conclusion.  Preventive home visits were not effective in reducing hospital readmissions, but satisfaction with care was enhanced. Subjective well‐being is a key variable that warrants attention in the planning and evaluation of postdischarge home care.
Utility, economic rationalism and the circumscription of agency
Authors: DiRita P. A. , Parmenter T. R. , Stancliffe R. J.
Published: May 2008

Background  Great strides have been achieved over the past few decades in service provision for people with intellectual disability (ID). However, there has also been a growth in the use of economic rationalism and a related rise in managerialism in forming service provision outcomes.

Method  An account of the focus on process and means of provision directed within the managerialist agenda to determine how individual authority has become subsumed within patterns of dependence.

Results  An underlying influence of utilitarianism has led to a focus on servicing the average through service provision trajectories which in turn have weakened the pace for social change and perpetuated a vulnerable conception of people with ID.

Conclusions  There has been a qualification of the idealised intent of providing individualised support, choice and recognition of the moral worth of people with ID into relative features of equality. There remains an overriding static conception of the person with ID within funding frameworks and service provision which relies on economic and rationalist depictions of the individual.
Serum levels of YKL‐40 and hyaluronic acid as noninvasive markers of liver fibrosis in haemodialysis patients with chronic hepatitis C virus infection
Authors: Schiavon L. L. , Narciso‐Schiavon J. L. , Carvalho Filho R. J. , Sampaio J. P. , Medina‐Pestana J. O. , Lanzoni V. P. , Silva A. E. B. , Ferraz M. L. G.
Published: May 2008

Summary.  Hepatitis C virus (HCV) infection is highly prevalent among end‐stage renal disease (ESRD) patients undergoing haemodialysis and it is an important cause of morbidity and mortality in this population. The aim of this study was to evaluate the diagnostic value of YKL‐40 and hyaluronic acid (HA) as noninvasive markers of liver fibrosis in 185 ESRD HCV‐infected patients. Significant liver fibrosis was defined as METAVIR F2, F3 or F4 stages. Significant fibrosis was observed in 45 patients (24%). By univariate analysis, higher levels of YKL‐40, HA, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma‐glutamyltransferase (GGT) as well as reduced platelet count were associated with fibrosis. However, by multivariate analysis, only AST (P = 0.001), platelet count (P = 0.004) and HA (P = 0.042) were independently associated with significant fibrosis. For the prediction of significant fibrosis, the areas under receiver operating characterictic curve (AUROC) of the regression model (0.798) was significantly higher than the AUROC of YKL‐40 (0.607) and HA (0.650). No difference was noted between the AUROC of the regression model and AST to platelet ratio index (APRI) (0.787). Values <8.38 of the regression model showed a negative predictive value of 94% and scores ≥9.6 exhibited a positive predictive value of 65%. If biopsy indication was restricted to scores in the intermediate range of the regression model, it could have been correctly avoided in 61% of the cases. In conclusion, APRI and a model based on AST, platelet count and HA showed better accuracy than YKL‐40 and HA (when used solely) for the prediction of significant fibrosis in ESRD HCV‐infected patients.
Branched oligosaccharide structures on HBV prevent interaction with both DC‐SIGN and L‐SIGN
Authors: Op den Brouw M. L. , De Jong M. A. W. P. , Ludwig I. S. , Van Der Molen R. G. , Janssen H. L. A. , Geijtenbeek T. B. H. , Woltman A. M.
Published: May 2008

Summary.  Hepatitis B virus (HBV) is a DNA virus that infects the liver as primary target. Currently, a high affinity receptor for HBV is still unknown. The dendritic cell specific C‐type lectin DC‐SIGN is involved in pathogen recognition through mannose and fucose containing carbohydrates leading to the induction of an anti‐viral immune response. Many glycosylated viruses subvert this immune surveillance function and exploit DC‐SIGN as a port of entry and for trans‐infection of target cells. The glycosylation pattern on HBV surface antigens (HBsAg) together with the tissue distribution of HBV would allow interaction between HBV and DC‐SIGN and its liver‐expressed homologue L‐SIGN. Therefore, a detailed study to investigate the binding of HBV to DC‐SIGN and L‐SIGN was performed. For HCV, both DC‐SIGN and L‐SIGN are known to bind envelope glycoproteins E1 and E2. Soluble DC‐SIGN and L‐SIGN specifically bound HCV virus‐like particles, but no interaction with either HBsAg or HepG2.2.15‐derived HBV was detected. Also, neither DC‐SIGN nor L‐SIGN transfected Raji cells bound HBsAg. In contrast, highly mannosylated HBV, obtained by treating HBV producing HepG2.2.15 cells with the α‐mannosidase I inhibitor kifunensine, is recognized by DC‐SIGN. The α‐mannosidase I trimming of N‐linked oligosaccharide structures thus prevents recognition by DC‐SIGN. On the basis of these findings, it is tempting to speculate that HBV exploits mannose trimming as a way to escape recognition by DC‐SIGN and thereby subvert a possible immune activation response.
The mRNA interferases, MazF‐mt3 and MazF‐mt7 from Mycobacterium tuberculosis target unique pentad sequences in single‐stranded RNA
Authors: Zhu Ling , Phadtare Sangita , Nariya Hirofumi , Ouyang Ming , Husson Robert N. , Inouye Masayori
Published: May 2008

mRNA interferases are sequence‐specific endoribonucleases encoded by toxin‐antitoxin (TA) systems in bacterial genomes. Previously, we demonstrated that Mycobacterium tuberculosis contains at least seven genes encoding MazF homologues (MazF‐mt1 to ‐mt7) and determined cleavage specificities for MazF‐mt1 and MazF‐mt6. Here we have developed a new general method for the determination of recognition sequences longer than three bases for mRNA interferases with the use of phage MS2 RNA as a substrate and CspA, an RNA chaperone, which prevents the formation of secondary structures in the RNA substrate. Using this method, we determined that MazF‐mt3 cleaves RNA at UU˘CCU or CU˘CCU and MazF‐mt7 at U˘CGCU (˘indicates the cleavage site). As pentad sequence recognition is more specific than those of previously characterized mRNA interferases, bioinformatics analysis was carried out to identify M. tuberculosis mRNAs that may be resistant to MazF‐mt3 and MazF‐mt7 cleavage. The pentad sequence was found to be significantly underrepresented in several genes, including members of the PE and PPE families, large families of proteins that play a role in tuberculosis immunity and pathogenesis. These data suggest that MazF‐mt3 and MazF‐mt7 or other mRNA interferases that target longer RNA sequences may alter protein expression through differential mRNA degradation, a regulatory mechanism that may allow adaptation to environmental conditions, including those encountered by pathogens such as M. tuberculosis during infection.
A novel pathway of intercellular signalling in Bacillus subtilis involves a protein with similarity to a component of type III secretion channels
Authors: Camp Amy H. , Losick Richard
Published: May 2008

During spore formation in Bacillus subtilis, σE‐directed gene expression in the mother‐cell compartment of the sporangium triggers the activation of σG in the forespore by a pathway of intercellular signalling that is composed of multiple proteins of unknown function. Here, we confirm that the vegetative protein SpoIIIJ, the forespore protein SpoIIQ and eight membrane proteins (SpoIIIAA through SpoIIIAH) produced in the mother cell under the control of σE are ordinarily required for intercellular signalling. In contrast, an anti‐σG factor previously implicated in the pathway is shown to be dispensable. We also present evidence suggesting that SpoIIIJ is a membrane protein translocase that facilitates the insertion of SpoIIIAE into the membrane. In addition, we report the isolation of a mutation that partially bypasses the requirement for SpoIIIJ and for SpoIIIAA through SpoIIIAG, but not for SpoIIIAH or SpoIIQ, in the activation of σG. We therefore propose that under certain genetic conditions, SpoIIIAH and SpoIIQ can constitute a minimal pathway for the activation of σG. Finally, based on the similarity of SpoIIIAH to a component of type III secretion systems, we speculate that signalling is mediated by a channel that links the mother cell to the forespore.
Molecular characterization of group A Streptococcus maltodextrin catabolism and its role in pharyngitis
Authors: Shelburne Samuel A. , Keith David B. , Davenport Michael T. , Horstmann Nicola , Brennan Richard G. , Musser James M.
Published: May 2008

We previously demonstrated that the cell‐surface lipoprotein MalE contributes to GAS maltose/maltodextrin utilization, but MalE inactivation does not completely abrogate GAS catabolism of maltose or maltotriose. Using a genome‐wide approach, we identified the GAS phosphotransferase system (PTS) responsible for non‐MalE maltose/maltotriose transport. This PTS is encoded by an open reading frame (M5005_spy1692) previously annotated as ptsG based on homology with the glucose PTS in Bacillus subtilis. Genetic inactivation of M5005_spy1692 significantly reduced transport rates of radiolabelled maltose and maltotriose, but not glucose, leading us to propose its reannotation as malT for maltose transporter. The ΔmalT, ΔmalE and ΔmalE:malT strains were significantly attenuated in their growth in human saliva and in their ability to catabolize α‐glucans digested by purified human salivary α‐amylase. Compared with wild‐type, the three isogenic mutant strains were significantly impaired in their ability to colonize the mouse oropharynx. Finally, we discovered that the transcript levels of maltodextrin utilization genes are regulated by competitive binding of the maltose repressor MalR and catabolite control protein A. These data provide novel insights into regulation of the GAS maltodextrin genes and their role in GAS host–pathogen interaction, thereby increasing the understanding of links between nutrient acquisition and virulence in common human pathogens.
Yeast mitochondria import ATP through the calcium‐dependent ATP‐Mg/Pi carrier Sal1p, and are ATP consumers during aerobic growth in glucose
Authors: Traba Javier , Froschauer Elisabeth Maria , Wiesenberger Gerlinde , Satrústegui Jorgina , Del Arco Araceli
Published: May 2008

Sal1p, a novel Ca2+‐dependent ATP‐Mg/Pi carrier, is essential in yeast lacking all adenine nucleotide translocases. By targeting luciferase to the mitochondrial matrix to monitor mitochondrial ATP levels, we show in isolated mitochondria that both ATP‐Mg and free ADP are taken up by Sal1p with a Km of 0.20 ± 0.03 mM and 0.28 ± 0.06 mM respectively. Nucleotide transport along Sal1p is strictly Ca2+ dependent. Ca2+ increases the Vmax with a S0.5 of 15 μM, and no changes in the Km for ATP‐Mg. Glucose sensing in yeast generates Ca2+ transients involving Ca2+ influx from the external medium. We find that carbon‐deprived cells respond to glucose with an immediate increase in mitochondrial ATP levels which is not observed in the presence of EGTA or in Sal1p‐deficient cells. Moreover, we now report that during normal aerobic growth on glucose, yeast mitochondria import ATP from the cytosol and hydrolyse it through H+‐ATP synthase. We identify two pathways for ATP uptake in mitochondria, the ADP/ATP carriers and Sal1p. Thus, during exponential growth on glucose, mitochondria are ATP consumers, as those from cells growing in anaerobic conditions or deprived of mitochondrial DNA which depend on cytosolic ATP and mitochondrial ATPase working in reverse to generate a mitochondrial membrane potential. In conclusion, the results show that growth on glucose requires ATP hydrolysis in mitochondria and recruits Sal1p as a Ca2+‐dependent mechanism to import ATP‐Mg from the cytosol. Whether this mechanism is used under similar settings in higher eukaryotes is an open question.
A novel preparation to study rat pancreatic spinal and vagal mechanosensitive afferents in vitro
Authors: Schloithe A. C. , Sutherland K. , Woods C. M. , Blackshaw L. A. , Davison J. S. , Toouli J. , Saccone G. T. P.
Published: May 2008

Abstract  The management of pancreatic pain is a significant clinical problem so understanding of how sensory signals are generated in pancreatic tissue is fundamental. We aimed to characterize mechanosensitive and chemosensitive properties of pancreatic spinal and vagal afferents in vitro. Spinal and vagal afferent preparations from Sprague–Dawley rats were established incorporating the left splanchnic nerve or vagus nerves respectively. The common bile duct was cannulated for distension of the pancreatic duct with fluid. Nerve discharge evoked by blunt probing, duct distension or electrical stimulation was obtained from teased nerve bundles using standard extra‐cellular recording. Discharge from 197 spinal afferent bundles was recorded, of which 57% displayed spontaneous activity. Blunt probing revealed 61 mechanosensitive receptive fields which were associated primarily with arteries/blood vessels (33/61) and the parenchyma (22/61). All mechanosensitive responses were slowly adapting, with 33% continuing to discharge after termination of the stimulus and 60% displaying a response threshold <10 g. Application of chemical mediators (bradykinin, histamine, 5‐hydroxytryptamine, cholecystokinin octapeptide) evoked a response from 31/57 units, with 33% excitatory and 23% inhibitory. Spontaneous discharge was recorded from 72% of 135 vagal bundles. Mechanosensitive receptive fields were not identified in the pancreas but were evident in adjacent organs. No spinal or vagal afferent response to duct distension was obtained. In conclusion, pancreatic mechanosensitive spinal afferents are common, in contrast to pancreatic mechanosensitive vagal afferents indicating that pancreatic sensory innervation is predominantly spinal. Chemosensitive spinal afferent nerve endings are present in the pancreas and respond to a variety of inflammatory and physiological mediators.
Natural Killer Cell Subpopulations in Putative Resistant Individuals and Patients with Active Mycobacterium tuberculosis Infection
Authors: Barcelos W. , Sathler‐Avelar R. , Martins‐Filho O. A. , Carvalho B. N. , Guimarães T. M. P. D. , Miranda S. S. , Andrade H. M. , Oliveira M. H. P. , Toledo V. P. C. P.
Published: May 2008

Herein, we intended to perform flow‐cytometric analyses of peripheral blood NK‐cell subsets in patients with active tuberculosis (TB) and those putative resistant subjects displaying positive tuberculin skin test (TST+) and compared with TST− healthy controls. Our findings demonstrated distinct phenotypic features in TST+ as compared with TB. While lower values of NK‐cells with increased frequency of CD3−CD16+ CD56− and CD3−CD16−CD56+ subsets besides lower frequency of CD3−CD16+ CD56+ NK‐cells was observed in TST+, unaltered levels of NK‐cells with increased levels of CD3−CD16+ CD56− NK‐cells with lower frequency of CD3−CD16+ CD56+ NK‐cells was found in TB. Additional analysis highlighted a shift towards increased levels of CD3−CD16−/+CD56bright NK‐cells as the hallmark of TST+, whereas unaltered frequency was observed in TB. Increased levels of CD3+CD56+ cells were observed in both TST+ and TB. Further focusing on the monocyte/NK‐cell network, we have reported that enhanced frequency of CD14+ CD16+ monocytes particularly observed in TST+. Outstanding were the distinct correlation profiles observed between CD3−CD16−CD56+ NK‐cells and CD3+ CD56+ cells CD14+ CD16+ monocytes for TST+ and TB. These data suggested that high levels of CD3−CD16−CD56+ NK‐cells aside CD14+ CD16+ monocytes as well as non‐concurrent increment of CD3+ CD56+ cells, may be involved in protective mechanisms in putative tuberculosis‐resistant individuals. On the other hand, the basal levels of macrophage‐like monocytes despite its positive correlation with increased levels of CD3+ CD56+ cells may count for the lack of the protective immunity in patients with active tuberculosis. Further studies focusing on the cytokine profiling of peripheral blood innate immunity cells before and after chemotherapic treatment are currently under evaluation.
Gene Array Analysis Comparison between Rat Collagen‐induced Arthritis and Human Rheumatoid Arthritis
Authors: Soto H. , Hevezi P. , Roth R. B. , Pahuja A. , Alleva D. , Acosta H. M. , Martinez C. , Ortega A. , Lopez A. , Araiza‐Casillas R. , Zlotnik A.
Published: May 2008

Collagen‐induced arthritis (CIA) is an experimental arthritis model used to study the inflammatory processes in this disease and test potential therapeutics. In order to better characterize this model, we conducted the first comprehensive gene expression analysis of rat CIA. To evaluate how closely the rat model reflects human rheumatoid arthritis (RA), we also analysed gene expression in human RA, using genome‐wide Affymetrix genearrays. By applying multiple strategies, including comparison of the highest induced genes, expression of immunological‐associated genes as well as Ingenuity Pathway Analysis (IPA), we were able to compare the two expression profiles. Among the highest induced genes in RA were several B‐cell‐associated genes, including immunoglobulins, B‐cell markers such as CD20, and cytokines and chemokines that act on B cells such as TNFSF13b/BLyS and CXCL13, none of which was upregulated in CIA. The latter was instead characterized by the upregulation of genes expressed primarily in macrophages and dendritic cells. Of the 22 pathways identified as significant in both diseases by IPA, only three (IL6, chemokine signalling and antigen presentation) were present in both settings. We conclude that there are significant differences in the inflammatory mechanisms between human RA and rat CIA, and that genome‐wide comparative gene expression analyses are useful tools to evaluate the relevance of animal models to human disease.
Hemolytic uremic syndrome recurrence after renal transplantation
Authors: Loirat Chantal , Fremeaux‐Bacchi Véronique
Published: May 2008

Abstract:  About 60% of non‐Stx‐associated aHUS are due to the defect of protection of endothelial cells from complement activation, secondary to mutations in the genes of CFH, MCP, IF, BF, or C3. In addition, 10% of patients have anti‐CFH antibodies. While the risk of post‐transplant recurrence is less than 1% in Stx‐HUS patients, it is approximately 80% in CFH or IF‐mutated patients, 20% in MCP‐mutated patients, and 30% in patients with no mutation. Patients with anti‐CFH antibodies probably also are at risk of recurrence. While MCP‐mutated patients can reasonably go to transplantation, recent reports suggest that plasmatherapy started before surgery and maintained life‐long may prevent recurrence in CFH‐mutated patients. Four successful liver–kidney transplantation utilizing plasmatherapy in CFH‐mutated children have been reported recently. In summary, the risk of post‐transplant recurrence can now be approached according to genotype. Therefore, aHUS patients should undergo complement determination, screening for anti‐CFH antibodies, and genotyping before transplantation. Kidney or kidney + liver transplantation with concomitant plasmatherapy need to be evaluated by prospective trials in patients with hereditary complement abnormalities.
Impact of pretransplant splenectomy on patients with β‐thalassemia major undergoing a matched‐related allogeneic stem cell transplantation
Authors: Mathews Vikram , George Biju , Lakshmi Kavitha M. , Viswabandya Auro , John Joseph M. , Sitaram Usha , Daniel Dolly , Chandy Mammen , Srivastava Alok
Published: May 2008

Abstract:  Impact of pretransplant splenectomy in patients with β‐thalassemia major undergoing an allogeneic SCT has never been addressed. Twenty‐seven class III patients (29 transplants) had a pretransplant splenectomy. The outcome of these 29 transplants was compared with 76 transplants in class III who did not have a splenectomy. Patients in the splenectomy group were older (11.7 ± 5.0 vs. 8.5 ± 3.5 yr; p = 0.003) and had a larger liver size (5.7 ± 1.8 vs. 4.4 ± 1.6 cm; p = 0.000). Splenectomized patients had a significantly faster time to ANC >500/mm3 (15.4 ± 5.9 vs. 17.5 ± 4 days; p = 0.002) and platelet >20 000/mm3 (22.5 ± 6.7 vs. 32.5 ± 13.6 days; p = 0.000). The splenectomized group had a significantly reduced requirement of blood transfusion in the first 100 days post‐transplant (5.5 ± 5.1 vs. 7.2 ± 5.4 units; p = 0.017). There were significantly more deaths related to peri‐transplant infections in the post‐splenectomy group (24% vs. 5.3%; p = 0.0001). The graft rejections were comparable between the two groups (20.7% vs. 14.5%; p = 0.55). The incidence of acute and chronic GVHD, late infections, and deaths from RRT was not significantly different between the two groups. The five‐yr EFS (31.0 ± 8.6 vs. 60.8 ± 5.98; p = 0.003) and OS (39.7 ± 9.3 vs. 71.8 ± 5.5; p = 0.002) was significantly worse in the splenectomized group. In conclusion, pretransplant splenectomy among patients with β‐thalassemia major was associated with faster engraftment, reduced transfusion support, a higher incidence of peri‐transplant infection related deaths, and a reduced EFS and OS.