bluuebunny/crossref_metadata_2025 huggingface dataset:
Additive effect of multiple pharmacological chaperones on maturation of CFTR processing mutants
Authors: Wang Ying , Loo Tip W. , Bartlett M. Claire , Clarke David M.
Published: August 2007

The most common cause of CF (cystic fibrosis) is the deletion of Phe508 (ΔF508) in the CFTR [CF TM (transmembrane) conductance regulator] chloride channel. One major problem with ΔF508 CFTR is that the protein is defective in folding so that little mature protein is delivered to the cell surface. Expression of ΔF508 CFTR in the presence of small molecules known as correctors or pharmacological chaperones can increase the level of mature protein. Unfortunately, the efficiency of corrector-induced maturation of ΔF508 CFTR is probably too low to have therapeutic value and approaches are needed to increase maturation efficiency. We postulated that expression of ΔF508 CFTR in the presence of multiple correctors that bound to different sites may have an additive effect on maturation. In support of this mechanism, we found that expression of P-glycoprotein (CFTR's sister protein) processing mutants in the presence of two compounds that bind to different sites (rhodamine B and Hoechst 33342) had an additive effect on maturation. Therefore we tested whether expression of ΔF508 CFTR in the presence of combinations of three different classes of corrector molecules would increase its maturation efficiency. It was found that the combination of the quinazoline VRT-325 together with the thiazole corr-2b or bisaminomethylbithiazole corr-4a doubled the steady-state maturation efficiency of ΔF508 CFTR (approx. 40% of total CFTR was mature protein) compared with expression in the presence of a single compound. The additive effect of the correctors on ΔF508 CFTR maturation suggests that they directly interact at different sites of the protein.
Mutant α-galactosidase A enzymes identified in Fabry disease patients with residual enzyme activity: biochemical characterization and restoration of normal intracellular processing by 1-deoxygalactonojirimycin
Authors: Ishii Satoshi , Chang Hui-Hwa , Kawasaki Kunito , Yasuda Kayo , Wu Hui-Li , Garman Scott C. , Fan Jian-Qiang
Published: August 2007

Fabry disease is a lysosomal storage disorder caused by the deficiency of α-Gal A (α-galactosidase A) activity. In order to understand the molecular mechanism underlying α-Gal A deficiency in Fabry disease patients with residual enzyme activity, enzymes with different missense mutations were purified from transfected COS-7 cells and the biochemical properties were characterized. The mutant enzymes detected in variant patients (A20P, E66Q, M72V, I91T, R112H, F113L, N215S, Q279E, M296I, M296V and R301Q), and those found mostly in mild classic patients (A97V, A156V, L166V and R356W) appeared to have normal Km and Vmax values. The degradation of all mutants (except E59K) was partially inhibited by treatment with kifunensine, a selective inhibitor of ER (endoplasmic reticulum) α-mannosidase I. Metabolic labelling and subcellular fractionation studies in COS-7 cells expressing the L166V and R301Q α-Gal A mutants indicated that the mutant protein was retained in the ER and degraded without processing. Addition of DGJ (1-deoxygalactonojirimycin) to the culture medium of COS-7 cells transfected with a large set of missense mutant α-Gal A cDNAs effectively increased both enzyme activity and protein yield. DGJ was capable of normalizing intracellular processing of mutant α-Gal A found in both classic (L166V) and variant (R301Q) Fabry disease patients. In addition, the residual enzyme activity in fibroblasts or lymphoblasts from both classic and variant hemizygous Fabry disease patients carrying a variety of missense mutations could be substantially increased by cultivation of the cells with DGJ. These results indicate that a large proportion of mutant enzymes in patients with residual enzyme activity are kinetically active. Excessive degradation in the ER could be responsible for the deficiency of enzyme activity in vivo, and the DGJ approach may be broadly applicable to Fabry disease patients with missense mutations.
Secreted PCSK9 promotes LDL receptor degradation independently of proteolytic activity
Authors: Li Jun , Tumanut Christine , Gavigan Julie-Ann , Huang Waan-Jeng , Hampton Eric N. , Tumanut Rachelle , Suen Ka Fai , Trauger John W. , Spraggon Glen , Lesley Scott A. , Liau Gene , Yowe David , Harris Jennifer L.
Published: August 2007

PCSK9 (proprotein convertase subtilisin/kexin 9) is a secreted serine protease that regulates cholesterol homoeostasis by inducing post-translational degradation of hepatic LDL-R [LDL (low-density lipoprotein) receptor]. Intramolecular autocatalytic processing of the PCSK9 zymogen in the endoplasmic reticulum results in a tightly associated complex between the prodomain and the catalytic domain. Although the autocatalytic processing event is required for proper secretion of PCSK9, the requirement of proteolytic activity in the regulation of LDL-R is currently unknown. Co-expression of the prodomain and the catalytic domain in trans allowed for production of a catalytically inactive secreted form of PCSK9. This catalytically inactive PCSK9 was characterized and shown to be functionally equivalent to the wild-type protein in lowering cellular LDL uptake and LDL-R levels. These findings suggest that, apart from autocatalytic processing, the protease activity of PCSK9 is not necessary for LDL-R regulation.
Aldosterone and end-organ damage
Authors: Marney Annis M. , Brown Nancy J.
Published: August 2007

Aldosterone concentrations are inappropriately high in many patients with hypertension, as well as in an increasing number of individuals with metabolic syndrome and sleep apnoea. A growing body of evidence suggests that aldosterone and/or activation of the MR (mineralocorticoid receptor) contributes to cardiovascular remodelling and renal injury in these conditions. In addition to causing sodium retention and increased blood pressure, MR activation induces oxidative stress, endothelial dysfunction, inflammation and subsequent fibrosis. The MR may be activated by aldosterone and cortisol or via transactivation by the AT1 (angiotenin II type 1) receptor through a mechanism involving the EGFR (epidermal growth factor receptor) and MAPK (mitogen-activated protein kinase) pathway. In addition, aldosterone can generate rapid non-genomic effects in the heart and vasculature. MR antagonism reduces mortality in patients with CHF (congestive heart failure) and following myocardial infarction. MR antagonism improves endothelial function in patients with CHF, reduces circulating biomarkers of cardiac fibrosis in CHF or following myocardial infarction, reduces blood pressure in resistant hypertension and decreases albuminuria in hypertensive and diabetic patients. In contrast, whereas adrenalectomy improves glucose homoeostasis in hyperaldosteronism, MR antagonism may worsen glucose homoeostasis and impairs endothelial function in diabetes, suggesting a possible detrimental effect of aldosterone via non-genomic pathways.
Host range of Acremonium cucurbitacearum, cause of Acremonium collapse of muskmelon
Authors: Armengol J. , Sanz E. , Martínez‐Ferrer G. , Sales R. , Bruton B. D. , García‐Jiménez J.
Published: August 2007

The pathogenicity of Acremonium cucurbitacearum to 31 cucurbits, 18 crop plant species, and 15 weed species was evaluated under greenhouse conditions. This study demonstrates that many other cucurbits in addition to muskmelon and watermelon can potentially serve as hosts of A. cucurbitacearum. Using a disease severity index (DSI), all muskmelon and watermelon cultivars were ranked as susceptible or highly susceptible, with the exception of honeydew cultivar TAM Dew Improved, which ranked resistant in one study. Highly resistant cucurbits included Cucurbita maxima (autumn squash), Luffa acutangula, L. aegyptiaca (sponge gourd) and Benincasa hispida (ash gourd). Cyclanthera pedata and Cucumis miriocarpus were rated as resistant. The percentage recovery of A. cucurbitacearum ranged from 8% to 100% and tended to be higher in plants with a higher DSI. Other crops and weed species common to muskmelon production fields are not likely to be involved in the perpetuation or propagation of the fungus.
Studies on dispersal of Septoria tritici pycnidiospores in wheat–clover intercrops
Authors: Bannon F. J. , Cooke B. M.
Published: August 2007

Four experiments studied the effects of a clover understorey on pycnidiospore dispersal of Septoria tritici in a wheat–clover intercrop under simulated rain. Clover significantly reduced the dispersal of spores in a horizontal direction by 33% at a distance of 15 cm from a line inoculum source compared with a wheat monocrop. The clover also reduced the vertical movement of spores from infected leaves at the base of wheat plants by an average of 63% compared to the monocrop, and this suggests that the main movement of spores was from the base upwards. Splash experiments using blue colour marker showed the vertical decline of splash and the number of drops per cm2 with height caught on paper adjacent to trays of clover was described by the exponential decline model. The effect of clover in reducing vertical splash approached an asymptote as the leaf area index of the understorey increased. Simulated rain‐splash increased the level of disease on the flag leaf and, in one experiment, there was a significant interaction between rain‐splash and clover in reducing the number of lesions on the flag leaf. The level of disease resulting from one splash event was low, indicating that subsequent pathogen multiplication is probably required to bring about high severities of disease.
Alterations in transpiration and stem vascular tissues of two maize cultivars under conditions of water stress and late wilt disease
Authors: Abd El‐Rahim M. F. , Fahmy G. M. , Fahmy Z. M.
Published: August 2007

Two cultivars of maize (Zea mays), Giza 2 (G2) and Population 45 (P45), were grown under natural conditions in pots containing clay loam soil, either infested or not infested with inoculum of Cephalosporium maydis, the causal fungus of late wilt disease. When the plants were 21 days old, they were subjected to two irrigation treatments: irrigation to field capacity, and irrigation after 60% depletion of the available soil moisture at the root zone, i.e. soil moisture stress. Under nonstressed conditions plants of cultivar G2 showed a lower percentage of infection than those of P45. In stressed plants, the percentage of infection increased significantly. Compared with controls (nonstressed, healthy plants), higher percentages of plant dry mass (leaves + stem + cobs) were achieved by all treatments with G2 than with P45, which did not produce cobs under stress conditions. Nonstressed healthy plants had higher transpiration rates and relative water contents than the water‐stressed diseased plants. The leaves of diseased plants had a higher content of the amino acid proline than those of nonstressed, healthy plants, probably associated with water stress due to the disease.

Infection resulted in a reduction of the number of the vascular bundles in the cross‐section of the internode. The values of the phloem area per unit leaf area were greatly reduced in water‐stressed and infected plants. In addition, many xylem vessels were occluded in diseased plants but much more in the susceptible P45 than in the moderately resistant G2. Occlusion may be the most important factor causing the symptoms of the disease.

The hydraulic conductance (Kh) of the xylem tissue supplying the transpiring areas was calculated from the conduit lumen diameters using the Hagen–Poiseuille relation. The highest Kh values were obtained in the nonstressed, healthy plants, particularly those of P45; plants with both water stress and disease showed the lowest Kh values. The efficiency of xylem conductance was further examined by calculations of the leaf specific conductance and the predicted maximum pressure gradients. Conductance was strongly reduced by infection in both cultivars and there was a corresponding increase in pressure gradients. These observations were consistent with observed reduction in xylem tissues and occlusion of xylem vessels by the infection.
Quantitative epidemiology of Banana Bunchy Top Virus Disease and its control
Authors: Smith M. C. , Holt J. , Kenyon L. , Foot C.
Published: August 2007

Models of a banana bunchy top virus disease epidemic were developed to incorporate the two key features of an epidemic in a plantation in the Philippines: an exponential increase in disease incidence over 10 years, and a declining gradient of incidence from the outside edge of the plantation to the centre. A non‐spatial model consisted of three difference equations to describe the numbers of latently infected and of infectious plants in the plantation and the size of the inoculum source outside the plantation. In a spatial model the outside portion of the plantation was divided into eight blocks running parallel to the outside edge. The dispersal gradient of the inoculum was assumed to be negative exponential. Analysis of the two models showed that for disease incidence to increase exponentially over time, the rate of disease progress could be dependent either on internal spread and roguing rate (proportion of diseased plants removed and replaced per unit time) or on the rate of increase of external inoculum pressure. The observed incidence gradient from the edge to the centre of the plot could be explained only if external inoculum dominated the parameters in the spatial model. This model was also used to explore a variable roguing rate across blocks. Simulations indicated that this may produce small gains over the adoption of a constant roguing rate over all blocks, but was risky because a shift of roguing emphasis only slightly too far towards the outside blocks can result in a dramatic increase in disease.
Comparing Sky Shape Skeletons for the Analysis of Visual Dynamics along Routes
Authors: Sarradin François , Siret Daniel , Couprie Michel , Teller Jacques
Published: August 2007

The motion of an observer in a given space produces a particular perception called motion perspective. This has been defined by Gibson as the gradual changes in the rate of displacements of contour lines in the visual field of the observer. This paper describes a new approach intended for analysing the motion perspective in order to quantify the morphology of urban open spaces along routes. It is based on spherical projections, which provide the shape of the sky boundary around the observer. The projections are studied through their skeletons, which are continuous sets of curves obtained by a progressive thinning down of the shapes around their main saliencies. The proposed method uses these skeletons to follow the variations in the shape of the sky boundary between the successive views. Measures of these variations have been developed and applied in a range of simplified theoretical examples and a real field example in order to show that they succeeded in capturing significant variations in spherical projections.
Making the Political Landscape Visible: Mapping and Analyzing Voting Patterns in an Ideological Space
Authors: Leuthold Heinrich , Hermann Michael , Fabrikant Sara Irina
Published: August 2007

This paper investigates the applicability of knowledge domain mapping for analyzing political science data. Utilizing metaphorical-space models grounded on political science theory, and applying sound cartographic visualization techniques, we demonstrate the construction and analysis of knowledge domain maps for exploring voting behaviour in Switzerland. We digitally transformed the results of Swiss popular referenda of the last twenty years to generate a 3-dimensional semantic space representing the current political landscape of Switzerland. The whole country is depicted in this semantic political space at various spatial scales. Locations in this spatialization represent aggregated voting outcomes from cities, regions, and provinces. Special attention was given to the interpretation of the resulting spatial configuration. This includes the assignment of meaning to the axes of the 3D space, depicted in two dimensions. Armed with political science theory locations in the voting behaviour space can be analyzed and the resulting political pattern can be interpreted meaningfully. The spatialized views were disseminated to the public after recent Swiss elections. The initial feedback from domain specialists and decision-makers alike has been very encouraging. Measured by high number of substantive reactions and wide-spread feedback on these spatializations of voting behaviour one could deduce that these abstract views were readily accepted and understood by public administrators, political party leaders, and the politically interested public. Based on these experiences we conclude the paper with a first attempt at identifying design recommendation for spatializing multidimensional political datasets.
Nature and causes of trends in male diabetes prevalence, undiagnosed diabetes, and the socioeconomic status health gradient
Authors: Smith James P.
Published: August 2007

This paper investigates levels in diabetes prevalence patterns across key socioeconomic status indicators and how they changed over time. The investigation spans both the conventional concept of diagnosed diabetes and a more comprehensive measure that includes those whose diabetes is undiagnosed. By doing so, I separate the distinct impact of covariates on trends over time in disease onset and the probability of disease diagnosis. The principal force leading to higher diabetes prevalence over time is excessive weight and obesity, which was only partially offset by improvements in the education of the population over time. Undiagnosed diabetes remains an important health problem, but much less so than 25 years ago. Although race and ethnic differentials in undiagnosed diabetes were eliminated over the last 25 years, the disparities became larger across other measures of disadvantage, such as education.
Evolution in the hypervariable environment of Madagascar
Authors: Dewar Robert E. , Richard Alison F.
Published: August 2007

We show that the diverse ecoregions of Madagascar share one distinctive climatic feature: unpredictable intra- or interannual precipitation compared with other regions with comparable rainfall. Climatic unpredictability is associated with unpredictable patterns of fruiting and flowering. It is argued that these features have shaped the evolution of distinctive characteristics in the mammalian fauna of the island. Endemic Herpestidae and Tenrecidae and members of five endemic primate families differ from closely related species elsewhere, exhibiting extremes of “fastness” and “slowness” in their life histories. Climatic features may also account for the dearth of frugivorous birds and mammals in Madagascar, and for the evolutionary prevalence of species with large body mass.
The (Un)Happiness of Knowledge and the Knowledge of (Un)Happiness: Happiness Research and Policies for Knowledge‐based Economies
1
Authors: Engelbrecht Hans‐Jürgen
Published: August 2007

This paper explores the current state and interfaces of two broad policy discourses, i.e. that of policies for knowledge‐based economies (KBEs) and policy implications of happiness research, which so far have exhibited little explicit cross‐referencing. I first review the state of ‘mainstream’ knowledge policy associated with the OECD, the related but somewhat separate literature on information society indicators, and some ‘non‐mainstream’ knowledge policy analysis. This is followed by a brief overview of some of the major policy implications and controversies in happiness research. Next, I discuss major interfaces of the two policy discourses. They mostly concern the nexus of education, work and innovation. I also illustrate the diversity of beliefs and values about some core elements of KBEs in a group of what are usually regarded as similar countries, and advocate the use of subjective variables to capture these differences. The main argument put forward in this paper is that policies for KBEs should be informed by insights from happiness research.
The Role of Knowledge Accumulation in Health and Longevity: The Puzzling Case of Suicide
Authors: Williams Ruth F. G. , Doessel D. P.
Published: August 2007

Many Western countries have experienced the ‘rectangularisation of the [demographic] survival curve’, leading to a rise in life expectancy. This process is the result of falling death rates, which leads to increasing longevity. In this article, suicide is placed within the general perspective of declining All Causes mortality. It is shown that suicide is atypical when compared with other causes of death. Which ever way it is measured, whether by an unweighted headcount measure or a weighted Potential Years of Life Lost measure, the suicide rate is not subject to secular decline. In fact, it has become (numerically) a relatively more important cause of death. This article puts some emphasis on the arguments by Joel Mokyr, an economic historian, about the importance of knowledge accumulation. It is argued that, in the case of suicide, there is a deficiency in knowledge of the causes of suicide and the prevention of suicide.
A case study of publication bias in an influential series of reviews of drug education
Authors: McCAMBRIDGE JIM
Published: August 2007

There has been remarkably little demonstration of the deleterious impact of publication bias within addiction science or indeed in wider healthcare policy and practice. An account is provided here of how publication bias was identified in relation to a series of drug education reviews which have been very influential on subsequent research, policy and practice. Later data analyses unpublished by the same review team demonstrated earlier findings to be unreliable. These later findings were not published. The policy context in which evidence on drug education in schools is produced is considered and the need for unbiased evidence is emphasised. A broadened conception of publication bias is proposed which takes account of the environment in which publication decision‐making occurs. It is suggested that this is particularly necessary for subjects with such direct policy relevance as the effectiveness of drug education in schools.
Patterns of alcohol intake of pregnant and lactating women in Perth, Australia
Authors: GIGLIA R. C. , BINNS C. W.
Published: August 2007

Introduction and Aims. Australian alcohol consumption data for women during the period of pregnancy and lactation is limited. The purpose of this paper is to provide current alcohol consumption data for pregnant and lactating women in Perth, Western Australia (WA). Data were collected from 587 women between mid‐September 2002 and mid‐July 2003.Design and Methods. Women from two public hospitals with maternity wards in the Perth metropolitan area completed a self‐administered baseline questionnaire while in hospital or shortly after discharge. All women, regardless of their chosen infant feeding method, were followed‐up by telephone interview at 4, 10, 16, 22, 32, 40 and 52 weeks postpartum. Data were analysed to determine alcohol use patterns of the women during the period of pregnancy and lactation and results were compared to national guidelines for alcohol consumption.Results. Approximately 32% of women stopped drinking alcohol during pregnancy. A remaining 35% of pregnant women consumed alcohol during pregnancy, with 82.2% of these women consuming up to two standard drinks per week. At 4, 6 and 12 months postpartum, 46.7%, 47.4% and 42.3% of breastfeeding women were consuming alcohol, respectively.Discussion and Conclusions. The majority of breastfeeding women consumed up to two standard drinks per week, which is within levels recommended by national authorities. There is, however, a small proportion of women consuming alcohol at levels above national recommendations for pregnancy and lactation. The development of ‘safe’ alcohol intake practices, within national recommendations, during the postnatal period would remove any potential health risks to the infant from alcohol exposure at this vulnerable growth stage.
Attitudes and beliefs towards methadone maintenance treatment among Australian prison health staff
Authors: GJERSING LINN R. , BUTLER TONY , CAPLEHORN JOHN R. M. , BELCHER JOSEPHINE M. , MATTHEWS RICHARD
Published: August 2007

Introduction and Aims. Justice Health NSW has one of the most extensive prison‐based methadone programmes in the world. We examine prison health staff attitudes towards methadone treatment and compare these with community methadone staff. Design and Methods. A cross‐sectional survey of 202 staff employed by Justice Health New South Wales was undertaken in 2003. Results. The mean scores on the various sub‐scales were: abstinence‐orientation (AO) 2.9 (95% CI 2.8‐3.0); disapproval of drug use (DDU) 3.3 (95% CI 3.2–3.4); knowledge (Know) 2.7 (95% CI 2.4‐2.9); and toxicity 4.6 (95% CI 4.2–5.0). Both the AO and DDU score were correlated negatively with the Know score (r = ‐0.37 and r = ‐0.13, respectively). Prison health staff had higher AO (2.9 vs. 2.6, p < 0.001) and DDU (3.3 vs. 2.6, p < 0.001) scores, and lower Know (2.7 vs. 7.0, p < 0.001) scores than methadone staff working in the Australian community. They were more knowledgeable than US community methadone staff about the toxicity of methadone (4.6 vs. 0.0, p < 0.001). Discussion and Conclusions. This is the first survey to examine prison health staff attitudes to methadone treatment. Correctional health staff tend to be more abstinence‐orientated, more likely to disapprove of drug use, and less knowledgeable about the risks and benefits of methadone than Australian community methadone staff. The findings have important implications for training health staff working in the prison environment with regard to client retention on methadone treatment.
Feasibility and acceptability of a mental health screening tool and training programme in the youth alcohol and other drug (AOD) sector
Authors: HIDES LEANNE , LUBMAN DAN I. , ELKINS KATHRYN , CATANIA LISA S. , ROGERS NICH
Published: August 2007

The high prevalence of co‐occurring mental health and substance use disorders in young people is well established. Despite this, there are low rates of detection of co‐occurring disorders across alcohol and other drug (AOD) services within Australia. This paper describes the development, implementation and evaluation of a mental health screening tool and training programme within the youth AOD sector. Thirty youth AOD workers received training in mental health screening, and the screening tool was subsequently piloted on 84 young people accessing two youth AOD services. Training was evaluated using measures of the trainee's mental health knowledge, attitudes, skills and confidence in mental health screening at baseline and 12‐month follow‐up. Feedback from young people supported the feasibility, acceptability and relevance of the screening tool. Evaluation of the associated training programme indicated improvements in AOD workers' mental health knowledge, skills and confidence in mental health screening. These findings provide preliminary evidence of the feasibility and acceptability of the mental health screening tool to young people and the effectiveness of the training package within the youth AOD sector.
Feasibility and outcomes of an innovative cognitive‐behavioural skill training programme for co‐occurring disorders in the youth alcohol and other drug (AOD) sector
Authors: HIDES LEANNE , ELKINS KATHRYN , CATANIA LISA S. , MATHIAS STEVE , KAY‐LAMBKIN FRANCES , LUBMAN DAN I.
Published: August 2007

There are limited treatment options available for young drug users with comorbid mental health problems who present to alcohol and other drug (AOD) services within Australia. While there is some evidence for the use of cognitive‐behaviour therapy (CBT) in the treatment of co‐occurring disorders, CBT is rarely used to address comorbidity in the AOD sector. This paper describes the development, implementation and evaluation of a brief cognitive‐behavioural skills (BCBS) training programme for addressing comorbidity within two youth AOD services in Australia. Ten youth AOD workers completed a 2‐day training programme in the BCBS. Training was evaluated using measures of trainees' cognitive‐behavioural knowledge, attitudes towards mental health interventions and level of skills and confidence in each of the BCBS pre‐ and 6 months post‐training. The BCBS training had a positive impact on the knowledge, skills and confidence of trainees and was perceived to be highly relevant and appropriate. These findings provide preliminary support for the feasibility and effectiveness of the BCBS training programme for workers within the youth AOD sector.
Contemporary cocaine use patterns and associated harms in Melbourne and Sydney, Australia
Authors: SHEARER JAMES , JOHNSTON JENNIFER , FRY CRAIG L. , KAYE SHARLENE , DILLON PAUL , DIETZE PAUL , COLLINS LINETTE
Published: August 2007

The aim of this paper was to explore the nature of cocaine use and harms through a cross‐sectional survey of cocaine users interviewed in the two largest Australian cities of Sydney (n = 88) and Melbourne (n = 77) between October 2004 and January 2005. The study supported previous findings that Australian cocaine users could be classified broadly into two types. The majority of cocaine users interviewed were classified as socially and economically integrated. They were young, employed, well‐educated people who generally snorted cocaine on a recreational basis, typically in conjunction with other illicit and licit drugs. A second group of socially and economically marginalised users, residing mainly in Sydney, injected cocaine often in conjunction with heroin. This group reported significantly higher levels of cocaine use, cocaine dependence, criminal behaviour and human immunodeficiency virus (HIV) risk‐taking behaviour. Heroin use was found to predict independently higher levels of cocaine use, criminal behaviour, needle sharing and physical problems in this sample, suggesting that increased resources and coverage for combined heroin/cocaine users may have scope for reducing cocaine‐related problems in the Australian community.
Drink a little; take a few drugs: do nurses have knowledge to identify and manage in‐patients at risk of drugs and alcohol?
Authors: GRIFFITHS R. D. , STONE A. , TRAN D. T. , FERNANDEZ R. S. , FORD K.
Published: August 2007

Introduction and Aims. The widespread use of alcohol and other drugs poses particular problems during hospitalisation. Although nurses have been identified as an appropriate group to screen patients and provide acute and ongoing management to people with drug and alcohol‐related problems, rates of screening are low. The aims of this study were to identify current practices for screening by nurses working in medical and surgical wards, determine their knowledge relating to problems associated with substance use and identify their self‐reported skills in managing patients with drug‐ and alcohol‐related problems. Design and Methods. A chart audit of medical records was completed and a survey was distributed to nurses working in the study wards. Results. Screening for alcohol and drug use was documented on only 22/79 medical records, and detailed information about quantity and duration of use was recorded in only nine. Overall, the nurses reported that they had little knowledge about substance use problems, and felt that they lacked skills to care adequately for these patients. Discussion and Conclusions. The results of this study suggest a need for a comprehensive training and education to ensure that nurses are familiar with policies and protocols for management of patients and to assist nurses to provide evidence‐based care and make appropriate referrals to specialist services.
Changing the density of alcohol outlets to reduce alcohol‐related problems
Authors: LIVINGSTON MICHAEL , CHIKRITZHS TANYA , ROOM ROBIN
Published: August 2007

Increasingly, it seems, legal and political debates regarding the granting of new liquor licences are turning to the issue of whether the number and density of alcohol outlets makes a difference in rates of alcohol consumption and alcohol‐related harm. But what is the state of the evidence on this question? In this Harm Reduction Digest Livingston, Chikritzhs and Room review the research literature on the effects of density of alcohol sales outlets on alcohol consumption and alcohol‐related problems; suggest a new way of conceptualising the relationships; and discuss the implications for reducing alcohol‐related harm.
EDITORIAL
Authors: SAUNDERS JOHN B.
Published: August 2007

Publication bias in addiction research
Histidine and not tyrosine is required for the Peroxide‐induced formation of haem to protein cross‐linked myoglobin
Authors: Reeder Brandon J. , Cutruzzolà Francesca , Bigotti Maria Giulia , Watmough Nicholas J. , Wilson Michael T.
Published: August 2007

Peroxide‐induced oxidative modifications of haem proteins such as myoglobin and haemoglobin can lead to the formation of a covalent bond between the haem and globin. These haem to protein cross‐linked forms of myoglobin and haemoglobin are cytotoxic and have been identified in pathological conditions in vivo. An understanding of the mechanism of haem to protein cross‐link formation could provide important information on the mechanisms of the oxidative processes that lead to pathological complications associated with the formation of these altered myoglobins and haemoglobins. We have re‐examined the mechanism of the formation of haem to protein cross‐link to test the previously reported hypothesis that the haem forms a covalent bond to the protein via the tyrosine 103 residue (Catalano, C. E., Choe, Y. S., Ortiz de Montellano, P. R., J. Biol. Chem. 1989, 10534 ‐ 10541). Comparison of native horse myoglobin, recombinant sperm whale myoglobin and Tyr103 → Phe sperm whale mutant shows that, contrary to the previously proposed mechanism of haem to protein cross‐link formation, the absence of tyrosine 103 has no impact on the formation of haem to protein cross‐links. In contrast, we have found that engineered myoglobins that lack the distal histidine residue either cannot generate haem to protein cross‐links or show greatly suppressed levels of modified protein. Moreover, addition of a distal histidine to myoglobin from Aplysia limacina, that naturally lacks this histidine, restores the haem protein's capacity to generate haem to protein cross‐links. The distal histidine is, therefore, vital for the formation of haem to protein cross‐link and we explore this outcome.
Searching for Neuroglobin's role in the brain
Authors: Nienhaus Karin , Nienhaus G. Ulrich
Published: August 2007

Neuroglobin is a small globin that plays an important role in the protection of brain neurons from ischemic and hypoxic injuries. The molecular mechanisms by which Ngb performs its physiological function are still under debate. Suggestions include oxygen storage and delivery, scavenging of NO and/or reactive oxygen species, oxygen sensing and signal transduction. In recent years, the molecular structures of Ngb with carbon monoxide bound to the heme iron and without an exogenous ligand have been solved, and interesting structural changes have been noticed upon ligand binding. Moreover, equilibrium and kinetic properties of the reactions with ligands have been examined in great detail. Here we summarize the molecular properties of Ngb and discuss them in relation to the potential physiological functions.
Allosteric effects on oxidative and nitrosative reactions of cell‐free hemoglobins
Authors: Bonaventura Celia , Henkens Robert , Alayash Abdu I. , Crumbliss Alvin L.
Published: August 2007

A review of the oxidative and nitrosative reactions of cell‐free hemoglobin‐based oxygen carriers (HBOCs) shows that these reactions are intimately linked and are subject to allosteric control. Cross‐linking reactions used to produce HBOCs introduce conformational constraints and result in Hbs with reduced responses to heterotropic and homotropic allosteric effectors. The Nernst plots of heme oxidation of cross‐linked HBOCs are shifted to higher potentials relative to unmodified Hb in the absence of allosteric effectors, in accord with their T‐state stabilization and right‐shifted Hill plots of O2 binding. They exhibit enhanced rates of autoxidation and nitrite‐induced oxidation, features that appear due to their having more solvent‐accessible heme pockets. The stability of their NO‐Hb derivatives varies as a result of allosteric effects on the extent of formation of pentacoordinate NO‐heme geometry by α chains and subsequent oxidation of partner β chains. The physiological implications of these findings on the safety, efficacy and design of second generation HBOCs are discussed in the framework of a reaction scheme showing linkages between Hb‐mediated redox reactions. These redox reactions can drive formation of SNO‐Hb and other reactive species and are of significance for the use of cell‐free Hbs in vivo.
Protein dynamics and function: Insights from the energy landscape and solvent slaving
Authors: Frauenfelder Hans , Fenimore Paul W. , Young Robert D.
Published: August 2007

Protein motions are complex and a good way to describe them is in terms of a very high‐dimensional conformation space. We give here a simple explanation of the conformation space and the energy landscape, the conformational motions and protein reactions, based on an analogy to a traffic problem. The analogy provides insight into the slaving of protein processes to bulk solvent fluctuations, in both the native and unfolded states.
Common dynamics of globin family proteins
Authors: Laberge Monique , Yonetani Takashi
Published: August 2007

The recently discovered new members of the globin family, neurogobin and cytoglobin, are the object of sustained structural and functional studies aimed at understanding their physiological role and elucidating the impact of their bis‐his heme hexacoordination. However, no studies have yet considered the dynamics of this protein family, an essential link between structure and function. In this communication, we present normal mode analysis results for neuroglobin, cytoglobin, hemoglobin and myoglobin to provide exploratory insights into globin characteristic motions. Our results show a clear correlation in the protein dynamics of this family. All four globins exhibit a high degree of correlated displacements involving residues in the C, E and F helices and link regions. They suggest that these motions play an important role in the reversible oxygen binding function of these proteins. Further, our results may help rationalize some functional features of the 6c‐globins in that they alone exhibit correlated displacements of the G‐helix region.
Protein structure in the truncated (2/2) hemoglobin family
Authors: Pesce Alessandra , Nardini Marco , Milani Mario , Bolognesi Martino
Published: August 2007

The discovery of protein sequences belonging to the widespread 'truncated hemoglobin' family has been followed in the last few years by extensive analyses of their three‐dimensional structures. Truncated hemoglobins can be classified in three main groups, in light of their overall structural properties. The three groups adopt a 2‐on‐2 α‐helical sandwich fold, based on four main α‐helices of the classical 3‐on‐3 α‐helical sandwich found in vertebrate and invertebrate globins. Each of the three groups displays sequence and structure specific features. Among these, a protein matrix tunnel system is typical of group I, a Trp residue at the G8 topological site is conserved in groups II and III, and residue TyrB10 is almost invariant in the three groups. Despite sequence variability in the heme distal site region, a strongly intertwined, but varied, network of hydrogen bonds stabilizes the heme ligand in the three protein groups. Fine mechanisms of ligand recognition and stabilization may vary based on group‐specific distal site residues and on differing ligand diffusion pathways to the heme. Taken together, the structural considerations here presented underline that 'truncated hemoglobins' result from careful editing of the 3‐on‐3 α‐helical globin sandwich fold, rather than from simple 'truncation' events. Thus, '2/2Hb' appears the most proper term to concisely address this protein family.
Ligand pathways in myoglobin: A review of trp cavity mutations
Authors: Olson J. S. , Soman J. , Phillips G. N.
Published: August 2007

The pathways for ligand entry and exit in myoglobin have now been well established by a wide variety of experimental results, including pico‐ to nano‐ to microsecond transient absorbance measurements and time‐resolved X‐ray crystallographic measurements. Trp insertions have been used to block, one at a time, the three major cavities occupied by photodissociated ligands. In this work, we review the effects of the L29(B10)W mutation, which places a large indole ring in the initial 'docking site' for photodissociated ligands. Then, the effects of blocking the Xe4 site with I28W, V68W, and I107W mutations and the Xe1 cavity with L89W, L104W, and F138W mutations are described. The structures of four of these mutants are shown for the first time (Trp28, Trp68, Trp107, and Trp 138 sperm whale metMb). All available results support a 'side path' mechanism in which ligands move into and out of myoglobin by outward rotation of the HisE7 side chain, but after entry can migrate into internal cavities, including the distal Xe4 and proximal Xe1 binding sites. The distal cavities act like the pocket of a baseball glove, catching the ligand and holding it long enough for the histidine gate to close and facilitate internal coordination with the heme iron atom. The physiological role of the proximal Xe1 site is less clear because changes in the size of this cavity have minimal effects on overall O2 binding parameters.
Electron transfer kinetics of soluble fragments indicate a direct interaction between complex III and the caa3 oxidase in Thermus thermophilus
Authors: Janzon Julia , Ludwig Bernd , Malatesta Francesco
Published: August 2007

The extremely thermophilic bacterium Thermus thermophilus expresses an aerobic respiratory chain resembling that of mitochondria and many mesophilic prokaryotes. Yet, interaction modes between redox partners differ between the thermophilic and mesophilic electron transport chains. While electron transfer in mesophilic organisms such as Paracoccus denitrificans follows a two‐step mechanism mostly governed by long‐range electrostatic interactions, the electron transfer in thermophiles is mediated mainly by apolar interactions. The terminal branch of the electron path from the bc‐complex via the soluble cytochrome c552 to the ba3 oxidase has extensively been characterized, whereas contradicting evidence has been put forward on the nature of the physiological substrate(s) of the caa3 oxidase. We have cloned and expressed a soluble fragment of the hydrophilic cytochrome c domain derived from subunit IIc of the caa3 oxidase (ccaa3) and characterized its kinetic behaviour in terms of substrate specificity and ionic strength dependency using pre‐steady state stopped‐flow techniques. The kinetics revealed fast electron transfer between the caa3 fragment and both, the cytochrome c552 and the soluble cytochrome cbc fragment of the bc‐complex, showing only a weak ionic strength dependence. These data suggest a direct intercomplex electron transfer between the bc‐complex and the caa3 oxidase without requirement for a soluble electron shuttle.
Twenty‐five years of cytochrome oxidase research in Rome with Maurizio Brunori
Authors: Antonini Giovanni , Malatesta Francesco , Sarti Paolo
Published: August 2007

Cytochrome c oxidase has been for a long time one of the central topics studied in Rome by Maurizio Brunori. The authors of this paper have had the unique opportunity of collaborating with him and his friends worldwide for many years. Among the very large number of papers on this enzyme produced by Maurizio Brunori, just a few have been selected here which are particularly representative for the three of us. Topics deal mostly with the interplay between the electrochemical potential gradient in its components and the electron transfer and the proton translocation reactions of this fascinating enzyme.
Cold‐adapted signal proteins: NMR structures of pheromones from the antarctic ciliate Euplotes nobilii
Authors: Placzek William J. , Etezady‐Esfarjani Touraj , Herrmann Torsten , Pedrini Bill , Peti Wolfgang , Alimenti Claudio , Luporini Pierangelo , Wüthrich Kurt
Published: August 2007

Cell type‐specific signal proteins, known as pheromones, are synthesized by ciliated protozoa in association with their self/nonself mating‐type systems, and are utilized to control the vegetative growth and mating stages of their life cycle. In species of the most ubiquitous ciliate, Euplotes, these pheromones form families of structurally homologous molecules, which are constitutively secreted into the extracellular environment, from where they can be isolated in sufficient amounts for chemical characterization. This paper describes the NMR structures of En‐1 and En‐2, which are members of the cold‐adapted pheromone family produced by Euplotes nobilii, a species inhabiting the freezing coastal waters of Antarctica. The structures were determined with the proteins from the natural source, using homonuclear 1H NMR techniques in combination with automated NOESY peak picking and NOE assignment. En‐1 and En‐2 have highly homologous global folds, which consist of a central three‐α‐helix bundle with an up‐down‐up topology and a 310‐helical turn near the N‐terminus. This fold is stabilized by four disulfide bonds and the helices are connected by bulging loops. Apparent structural specificity resides in the variable C‐terminal regions of the pheromones. The NMR structures of En‐1 and En‐2 provide novel insights into the cold‐adaptive modifications that distinguish the E. nobilii pheromone family from the closely related E. raikovi pheromone family isolated from temperate waters.
Evolution of allosteric models for hemoglobin
Authors: Eaton William A. , Henry Eric R. , Hofrichter James , Bettati Stefano , Viappiani Cristiano , Mozzarelli Andrea
Published: August 2007

We compare various allosteric models that have been proposed to explain cooperative oxygen binding to hemoglobin, including the two‐state allosteric model of Monod, Wyman, and Changeux (MWC), the Cooperon model of Brunori, the model of Szabo and Karplus (SK) based on the stereochemical mechanism of Perutz, the generalization of the SK model by Lee and Karplus (SKL), and the Tertiary Two‐State (TTS) model of Henry, Bettati, Hofrichter and Eaton. The preponderance of experimental evidence favors the TTS model which postulates an equilibrium between high (r)‐ and low (t)‐affinity tertiary conformations that are present in both the T and R quaternary structures. Cooperative oxygenation in this model arises from the shift of T to R, as in MWC, but with a significant population of both r and t conformations in the liganded T and in the unliganded R quaternary structures. The TTS model may be considered a combination of the SK and SKL models, and these models provide a framework for a structural interpretation of the TTS parameters. The most compelling evidence in favor of the TTS model is the nanosecond ‐ millisecond carbon monoxide (CO) rebinding kinetics in photodissociation experiments on hemoglobin encapsulated in silica gels. The polymeric network of the gel prevents any tertiary or quaternary conformational changes on the sub‐second time scale, thereby permitting the subunit conformations prior to CO photodissociation to be determined from their ligand rebinding kinetics. These experiments show that a large fraction of liganded subunits in the T quaternary structure have the same functional conformation as liganded subunits in the R quaternary structure, an experimental finding inconsistent with the MWC, Cooperon, SK, and SKL models, but readily explained by the TTS model as rebinding to r subunits in T. We propose an additional experiment to test another key prediction of the TTS model, namely that a fraction of subunits in the unliganded R quaternary structure has the same functional conformation (t) as unliganded subunits in the T quaternary structure.