bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the central–local relationship in health care: A new approach
Authors: De Roo Aad A. , Maarse Hans A. M.
Published: May 2007

One of the basic assumptions of governmental health planning policy is that the government can effectively take final responsibility for the development of the health care system. Failure to reach policy goals is explained in terms of inadequate planning technology and instruments to control implementation. In this article an alternative explanation is offered, based on the theory of strategic organizational behavior. According to this theory, the government must be seen as but one actor in a complex interorganizational network. From this, a different perspective on effective health planning policy is developed. Policies will fail if they are not based on a valid analysis of the policy space of health care institutions and the interdependencies between government and health care organizations.

This article starts with an outline of the nature of the central‐local relationship as seen from the perspective of strategic organizational behavior theory. Next, this theory is used to frame two cases in which Dutch health care institutions successfully pursued their own strategies that ran counter to the existing health planning policies. The article ends with a discussion of the implications of the theory of strategic organizational behavior for the development of effective central health care policies. This development starts with a thorough analysis of the policy space and interdependencies of all relevant actors in the health system, the government included. Following, policy makers can set the governmental goals and then have to start negotiations with health care institutions about mutual adaptation of their strategies and the governmental goals. The result is a negotiated health care order.
Job satisfaction of health workers
Authors: Tennakoon Senarath
Published: May 2007

A postal questionnaire was sent to a stratified random sample of 33.6% (556 out of 1655) of health workers representing five occupational groups in the Ratnapura Health Region, Sri Lanka, to discover their intensity of job satisfaction.

The overall response rate was 60.3% (335 out of 556), being highest among the nurses (P < 0.01) and lowest among the medical practitioners (P < 0.001).

Of the respondents, 70.0% (237 out of 335) were generally satisfied with the occupational environment. For 14.8% (26 out of 175) of the minor employees it was ‘excellent most of the time’ and for 19.6% (11 out of 56) of midwives it was extremely uncongenial. The immediate supervisor was described as ‘fair at all times’ by 50.4% (169 out of 335); being 61.7% (108 out of 175) among the minor employees and 21.4% (8 out of 37) among the nurses.

Community relationships were described as ‘satisfactory’ by 46.5% (156 out of 335); this being 26.3% (88 out of 175) among the minor employees and 56.2% (18 out of 32) among the middle technical officers. The fellow workers were described as co‐operative by 34.1% (114 out of 335) and as ‘all right’ by 34.9% (117 out of 335).

Thirty seven per cent (124 out of 335) declared that their personal problems were not affecting their work and 20% (67 out of 335) gave the reply as ‘absolutely no’. The latter reply was highest among the medical practitioners (28.6% or 10 out of 35) and nurses (27.0% or 10 out of 37) respectively.

About the factors affecting work, more medical practitioners (57.1% or 20 out of 35) and nurses (67.6% or 25 out of 37) were concerned about staff shortages; more middle technical officers (40.6% or 13 out of 32) and minor employees (37.7% or 66 out of 175) were worried about inadequate incentives and more midwives (50.0% or 28 out of 56) and minor employees (34.8% or 61 out of 175) were not happy with their poor pay. The health department was described as ‘decidedly the best of all government departments’ by 43.3% (76 out of 175) of the minor employees and as ‘better than most other government departments’ by 56.8% (21 out of 37) of the nurses, while 54.4% (19 out of 35) of the medical practitioners failed to find any differences between the health sector and other government sectors.

The majority (62.1%) have expressed job satisfaction. Respondents' views on occupational environment, immediate supervisor, community relationships, personal problems and key factors affecting work performance were very significantly diverse among the difference occupations (P < 0.001).
A mobile breast screening project in Scotland: Lessons learned for national screening
Authors: Haiart D. C. , Henderson J. , McKenzie L. , Kirkpatrick A. E.
Published: May 2007

In 1986, a project was undertaken to determine the feasibility and cost of screening for breast cancer, using single oblique view mammography. Screening was offered to women aged between 40 and 65, on an open access basis, to those living in rural areas near Edinburgh. This article reports on: the logistical difficulties encountered; the costs of mobile screening; a comparison of costs when screening from a static centre; and, identifies factors found to influence attendance rates. The lessons learned from the project were incorporated into the planning of the mobile van operating in the South‐East of Scotland Screening Programme, part of the National Breast Screening Programme; comparisons, where possible, have been included.
New concepts in health care: Some preliminary ideas
Authors: Rutgers Maarten J. , Berkel Hans
Published: May 2007

Health care discussions in many countries tend to focus on cost containment without taking into account the problem of quality of care. The starting point for our ideas is the description of quality as the optimal relation between care demander and care provider. The difficulties in assessing quality of care are outlined. The question remains which health care model offers the best opportunities to have both high quality care and affordable costs. A proposal is made for a model in which the care demander and care provider, i.e. the client and physician, are natural allies. A special role is fulfilled by the family physician: a key role, as case manager, as gatekeeper. Special attention should be directed towards the financial consequences. It is proposed that small‐scale experiments should be started to evaluate the model advanced in the text.
Privatizing health care: Caveat emptor
Authors: Young David W.
Published: May 2007

Many Western European countries are moving toward privatization of their health care systems. The United States' health care system, since it is almost entirely privatized, is therefore worthy of study. Doing so raises several questions. How is privatization being managed in the US? How could its management be improved? What management lessons must be kept in mind if it is to be used effectively? What potential pitfalls should European countries consider as they move toward greater privatization?

With operating costs, European countries must avoid the mistakes that have led to dramatic increases in annual health care costs in the US, simultaneous with reductions in access and quality. Doing so requires designing systems that promote hospital behavior consistent with a country's health objectives.

With capital costs, an approach must be designed that allows policy‐makers to work closely with both managers and physicians in order to make strategically sound choices about access and quality. Such an approach will require physicians to incorporate their clinical judgments into community standards of care, and to adopt a regional (rather than an institutional or personal) perspective in the determination of any incremental capital expenditures.

By making regulation proactive and strategic, rather than punitive, health policymakers in Western Europe can achieve the best privatization has to offer without feeling the sting of its unintended consequences. In so doing they can help to move their health systems toward achieving the multiple and illusive goals of access, quality and reasonable cost.
An analysis of three national health insurance proposals in Sub‐Saharan Africa
Authors: Vogel Ronald J.
Published: May 2007

The financing and/or provision of health insurance by government has a theoretical basis: it stems from market failure in the private health insurance market; and, from externalities in the consumption of health care by the poor. Government health insurance, or national health insurance (NHI) may be analysed by using five criteria: who are the beneficiaries?; efficiency effects; the equity of financing; the level of administrative costs; and, political acceptability. In the last five years, Ghana, Zimbabwe and Nigeria have each considered proposals for NHI. However, each proposal shows design flaws, when analysed in the light of the five criteria above. This article first considers types of health insurance in Sub‐Saharan Africa, and why NHI, with cost recovery as an essential component, might be desirable. A following section present an outline of the NHI proposals in Ghana, Zimbabwe and Nigeria and points out the design flaws. A final section builds upon the theoretically‐good aspects of the three proposals, and considers some alternate approaches to NHI that these three countries and other countries in the Sub‐Sahara might want to consider.
A price to pay, part 2: The impact of user charges in the Volta region of Ghana
Authors: Waddington Catriona , Enyimayew K. A.
Published: May 2007

This paper looks at what happened in Ghana following increases in government health service charges in 1983 and 1985. A combination of analysis of records, interviews and discussion with community groups was used.

Utilization in rural areas was affected drastically by the substantial increase of 1985. The effect on urban utilization was less extreme and less durable. The age composition of users changed. After the 1985 increase, proportionately more of the 15‐45 age group used the government services—this was particularly at the expense of the over‐45s. The population was obviously concerned with the cost of health care, but were even more concerned about the quality of care and receiving value‐for‐money. They were unwilling to pay if drug supplies were unreliable or staff behaved unpleasantly.

Some problems were encountered with implementing the policy of charges. Many facilities did not spend the revenue to which they were entitled—an interesting point, as the existence of the skill to spend money is often tacitly assumed!

Charges also had significant indirect resource consequences. Reduced utilization freed up staff time which should be used to provide other services, particularly preventive ones. This opportunity has not, as yet, been exploited.

Fee revenue can be dangerously attractive, particularly if it is administratively more accessible than general government allocations. There is a danger that revenue collection becomes a disproportionately important evaluative criterion in a system which is, after all, ultimately intended to improve health status.
An income‐weighted international average for comparative analysis of health expenditures
Authors: Getzen Thomas E. , Poullier Jean‐Pierre
Published: May 2007

Data from 17 countries across 28 years are used to estimate an international health expenditure function based on real per capita GNP. Actual and expected spending levels are compared for 24 countries. Between 1960 and 1987, it has been rare for health expenditure in any country to be more than ± 20 per cent from the projected value. The norm is for spending to rise at 1.5 times the growth rate of GDP. Two countries appear to display significant anomalies. Spending in the United Kingdom is consistently 15–25 per cent below normal for all years, and Danish expenditure has declined from 7 to 6 per cent of GDP since 1975.
Health for all nigerians: Some revolutionary management dimensions
Authors: Lambo Eyitayo
Published: May 2007

Health For All by the Year 2000, usually referred to as HFA/2000, is a goal that has been accepted by most nations of the world. PHC is the strategy designed to achieve this laudable goal. In Nigeria, there is no doubt that remarkable strides have been made to achieve the goal of HFA/2000 in recent years. However, in order to fully realise this goal, some further revolutionary management steps are needed. This article first examines the progress on HFA made so far in Nigeria; and then, discusses some management initiatives that need to be taken or accelerated to be able to reach that desirable destination.
Management development for primary health care: A framework for analysis
Authors: Cassels Andrew , Janovsky Katja
Published: May 2007

Strengthening management has been widely promoted as a critical component of any strategy concerned with improving the implementation of primary health care (PHC). Management development programmes are, however, subject to conflicting demands and differing expectations. The situation is confounded by the wide diversity of strategies subsumed under the heading of management development, and the confusing nature of much of the terminology currently in use. This article presents a simple conceptual framework that can guide analysis and help programme planners review the options, opportunities and limitations of management development programmes. The framework presented examines management development from three different perspectives: the approach adopted; the outcomes expected; and the process of expansion, extension and adaptation.

Our analysis of management development strategies allows us to reach some conclusions in areas where there is a degree of consensus. In countries where there is a mismatch between the strategies of PHC and the organizational structures through which they are to be implemented, management development has a role to play in effecting change. Its potential to do so is limited by powerful social, political, economic and organizational forces. Therefore, the capacity to critically analyse the context in which change is planned, emerges as a key element in programme design. We argue that there is no one best approach to management development, and the design of strategies will be contingent on a variety of factors. We do, however, reaffirm the view that where organizational structures and conditions do not support the implementation of PHC strategies, intervention through training alone is almost certain to be inadequate. To be effective, a more comprehensive programme will be required. Finally, the article points to a number of unresolved issues in areas where there is either controversy, lack of clarity or limited experience.
Hospital role delineation: The technology and the politics
Authors: Duckett Stephen
Published: May 2007

Regulated health systems are under increasing pressure to improve the efficiency of their hospital provision. One approach is to have more coordinated hospital provision through hospital role delineation. This short communication proposes the use of Diagnosis Related Groups as part of the role delineation process. However, the role delineation process is not solely a technical one: it requires a blend of technical and political decisions. Political aspects of the role delineation process are also reviewed.
Managing the unmanageable: Public hospital systems
Authors: Boufford Jo Ivey
Published: May 2007

There are significant challenges to those who work in large public health care delivery systems: political imperatives; resource constraints; sometimes rigid personnel systems; and, the reality that everything occurs in a public forum. The fact that many nations are reviewing and, in some instances, restructuring their national health care systems, has added to the complexity and feeling of continual turbulence experienced by their managers. State run systems like that in the United Kingdom are introducing market forces to increase effectiveness and value for money; while market systems, like that in the United States, are increasing regulatory interventions to achieve the kind of cost control available to countries with large public systems which operate with global budgets.

Public hospitals in the United States offer examples of public institutions operating in a highly competitive market environment. A decade of management changes undertaken to enhance the efficiency and effectiveness of the New York City Health and Hospitals Corporation (HHC), the largest public hospital system in the United States, is presented as a case study of public health services and public management in a market environment.
Preliminary spectral characterization of snow in a high altitude tropical glacier and potential effects of impurities in snow on albedo of tropical glaciers
Authors: Sicart Jean Emmanuel , Arnaud Yves
Published: May 2007

This paper presents some preliminary measurements of snow spectral reflectance on the tropical Bolivian Zongo glacier. Measurements show a correct agreement with theoretical spectral albedo of pure snow in the near infrared region, but lower values in the visible region (by 10–20%) probably due to aerosols contained in snow. Impurity contents ranged from 10 to 100 ppmw in one‐week‐old snow collected from the Zongo glacier, but measurements are scarce. Large amounts of snowfall partly compensate the proximity of dust sources in mid‐latitude glaciers, whereas on outer‐tropical glaciers precipitations are not abundant and are very seasonal, and sources of aerosols are proximate. Copyright © 2007 John Wiley & Sons, Ltd.
Individual and joint use of statins and low‐dose aspirin and risk of colorectal cancer: A population‐based case–control study
Authors: Hoffmeister Michael , Chang‐Claude Jenny , Brenner Hermann
Published: May 2007

Recent research has drawn attention to protective effects of statins on colorectal cancer (CRC) and possible joint effects with other drugs. Because statins are often administered in combination with low‐dose aspirin for the prevention of cardiovascular disease, the aim of our study was to investigate individual and combined effects of statins and low‐dose aspirin on CRC risk. We assessed use of statins and low‐dose aspirin in 540 cases with histologically confirmed incident CRC and 614 control subjects in a population‐based case–control study in Germany. Multiple logistic regression was used to estimate the impact of regular use of either low‐dose aspirin or statins, and of both drugs combined on CRC risk. We found modest risk reduction of CRC for regular use of low‐dose aspirin (adjusted odds ratio 0.77, 95% confidence interval 0.55–1.07) and a stronger association with regular use of statins (OR 0.65, 95% CI 0.43–0.99) or use of both drugs (OR 0.63, 95% CI 0.36–1.10). Combined use of low‐dose aspirin and statins was associated with risk reduction by 62% after 5 or more years (OR 0.38, 95% CI 0.15–0.97). Combinational chemoprevention with low‐dose aspirin and statins might provide stronger risk reduction than either of the single drugs after at least 5 years use, but confirmation is needed, preferably in prospective cohort studies and eventually by randomized controlled trials. © 2007 Wiley‐Liss, Inc.
Fat and meat intake and prostate cancer risk: The multiethnic cohort study
Authors: Park Song‐Yi , Murphy Suzanne P. , Wilkens Lynne R. , Henderson Brian E. , Kolonel Laurence N.
Published: May 2007

Dietary fat and meat as potential risk factors for prostate cancer have been the focus of many epidemiologic investigations, and findings from recent studies in particular have been inconsistent. Therefore, we examined the association between these exposures and prostate cancer risk in the Multiethnic Cohort Study. The analyses included 82,483 men in Hawaii and Los Angeles aged ≥45, who completed a detailed quantitative food frequency questionnaire in 1993–1996. During the follow‐up period of 8 years, a total of 4,404 incident cases, including 1,278 nonlocalized or high‐grade cancer cases, were identified. Cox proportional hazard models were used to estimate relative risks of prostate cancer after adjustment for time on study, ethnicity, family history of prostate cancer, education, body mass index, smoking status and energy intake. Intake of different types of fat (total, saturated, monounsaturated or polyunsaturated), n‐6 fatty acid, cholesterol, various meats, and fats from meat showed no association with overall prostate cancer risk or with nonlocalized or high‐grade prostate cancer. Furthermore, we found little evidence of any relation of fat and meat intake with prostate cancer risk within any of the 4 racial/ethnic groups (African Americans, Japanese Americans, Latinos and Whites). There was a suggestion of a protective effect of n‐3 fatty acid intake that was limited to Latinos and Whites. However, overall, our findings from a large cohort study of ethnically diverse population give no indication that intake of fat and meat substantially affects prostate cancer risk. © 2007 Wiley‐Liss, Inc.
Racial differences in clinical and pathological associations with PhIP‐DNA adducts in prostate
Authors: Tang Deliang , Liu Jason J. , Bock Cathryn H. , Neslund‐Dudas Christine , Rundle Andrew , Savera Adnan T. , Yang James J. , Nock Nora L. , Rybicki Benjamin A.
Published: May 2007

African–American men have a higher dietary intake of 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP), which is the most abundant heterocyclic amine in cooked meats and is carcinogenic in rat prostate through the formation of DNA adducts. To determine the clinical and demographic factors associated with PhIP‐DNA adduct levels, the biologically effective dose of PhIP in human prostate, we immunohistochemically measured PhIP‐DNA adducts in a study of 162 Caucasian and 102 African–American men who underwent radical prostatectomy for prostate cancer. A strong correlation between PhIP‐DNA adduct levels in prostate tumor and adjacent non‐tumor cells was observed (ρ = 0.62; p < 0.0001); however, non‐tumor cells had significantly higher adduct levels compared with tumor (0.167 optical density (OD) units ± 0.043 vs. 0.104 OD ± 0.027; p < 0.0001). Race was not associated with PhIP‐DNA adduct levels in either tumor or non‐tumor cells, but race‐specific associations were observed. In prostate tumor and non‐tumor cells, tumor volume had the strongest association with PhIP‐DNA adducts in Caucasians, whereas in African–Americans prostate volume was most strongly associated with adduct levels in tumor cells and advanced Gleason grade had the strongest association in non‐tumor cells. In race interaction models, while the only statistically significant interaction was between African–American race and advanced Gleason grade in non‐tumor cells (β = 0.029; p = 0.02), in tumor cells we observed opposite effects by race (positive for African–Americans, negative for Caucasians) for older age and high PSA levels at diagnosis. In conclusion, while PhIP‐DNA adduct levels in prostate cells do not vary significantly by race, our results suggest that PhIP exposure may have stronger effects on prostate tumor differentiation in African–American men. © 2007 Wiley‐Liss, Inc.
Thermographic assessment of tumor growth in mouse xenografts
Authors: Song Chengli , Appleyard Virginia , Murray Karen , Frank Tim , Sibbett Wilson , Cuschieri Alfred , Thompson Alastair
Published: May 2007

In human breast tumors, a 1–2°C increase in skin surface temperature is usually observed at the periphery; it has been proposed that this change is due to the hypervascularity and increased blood flow resulting from tumor‐associated angiogenesis. Here we tested the hypothesis that thermal imaging might represent a useful adjunctive technique in monitoring the growth dynamics of human tumor xenografts. Xenografts were established in immunocomprised nude mice using MDA‐MB‐231 or MCF7 breast cancer cells. We exploited the inherent noncontact and noninvasive advantages of infrared thermography to detect skin surface temperature changes. Continuous thermographic investigation was performed to detect and monitor tumor growth in vivo and high resolution digital images were analyzed to measure the tumor temperature dynamics. In contrast to the skin temperature increases associated with human breast cancer, a consistent temperature decrease was found in the xenograft mice. In one case, a smaller secondary tumor, otherwise undetectable, was clearly evident by thermal imaging. The tumors were cooler than the surrounding tissue with a maximum temperature reduction of 1.5°C for MDA‐MB‐231 tumor and 3°C for MCF7 tumors observed on day 14. In addition, the temperature of the xenograft tumors decreased progressively as they grew throughout the observation period. It was demonstrated that thermographic imaging could detect temperature changes as small as 0.1°C on the skin surface at an early stage of tumor development. The findings of the study indicate that thermographic imaging might have considerable potential in monitoring human tumor xenografts and their response to anticancer drugs. © 2007 Wiley‐Liss, Inc.
Impact of HER2 and EGFR gene status on gefitinib‐treated patients with nonsmall‐cell lung cancer
Authors: Soh Junichi , Toyooka Shinichi , Ichihara Shuji , Fujiwara Yoshiro , Hotta Katsuyuki , Suehisa Hiroshi , Kobayashi Naruyuki , Ichimura Kouichi , Aoe Keisuke , Aoe Motoi , Kiura Katsuyuki , Date Hiroshi
Published: May 2007

We previously examined the relationship between epidermal growth factor receptor (EGFR) status and clinical outcomes of nonsmall‐cell lung cancer (NSCLC) patients treated with gefitinib. In our study, we additionally examined HER2 status and investigate the impact of genetic status as predictors in Japanese NSCLC patients treated with gefitinib. The HER2 copy number status was determined by fluorescence in situ hybridization assay and mutation of HER2 exon 20 was determined by direct sequencing in 74 patients to investigate the relationship between molecular statuses including HER2 and EGFR and the clinical outcomes of patients treated with gefitinib. The high HER2 copy number was identified in 32 (43.2%) of 74 NSCLC patients and no HER2 exon 20 mutations were found. The high HER2 copy number was significantly associated with the sensitivity to gefitinib (p = 0.0045) and a prolonged progression‐free survival (PFS) (p = 0.0089) in a univariate analysis, but not in a multivariate analysis. Multivariate analyses exhibited that the drug‐sensitive EGFR mutation was an independent predictive factor of a better sensitivity to gefitinib (OR = 41.9, p = 0.002), prolonged overall survival (HR = 0.32, p = 0.019) and PFS (HR = 0.31, p = 0.0045). The high EGFR copy number might have a weak association with better response and prognosis without statistical significance. In conclusion, the drug‐sensitive EGFR mutation, rather than HER2 and EGFR copy numbers, is a determinant of favorable clinical outcomes in gefitinib‐treated patients with NSCLC, although the high HER2 copy number, to some extent, may influence the gefitinib effect. © 2007 Wiley‐Liss, Inc.
The role of trophinin, an adhesion molecule unique to human trophoblasts, in progression of colorectal cancer
Authors: Harada Oi , Suga Tomoaki , Suzuki Takefumi , Nakamoto Katsuaki , Kobayashi Motohiro , Nomiyama Tetsuo , Nadano Daita , Ohyama Chikara , Fukuda Michiko N. , Nakayama Jun
Published: May 2007

Trophinin is a unique adhesion molecule expressed by human trophoblastic cells. Its activity and in vivo expression pattern implicate trophinin in the initial attachment of trophectoderm cells to maternal epithelia. Subsequent to apical adhesion, trophoblasts aggressively invade maternal tissue to form the placenta, a process resembling tumor invasion. Here, we report that trophinin is expressed in tumors from 64% of colon cancer patients (n = 50) and high trophinin expression is closely associated with poor prognosis. To determine the link between trophinin expression and malignancy, colon adenocarcinoma SW480 cells were stably transfected with trophinin. An invasion assay showed that trophinin‐expressing SW480 cells were more invasive than mock‐transfected cells. Microarray analysis comparing SW480 cells transfected with trophinin with mock‐transfected cells identified high‐mobility group box 1 (HMGB1) as the most significantly elevated transcript. Immunohistochemical analysis of tumors from the colorectal cancer patients confirmed positive correlation of HMGB1 protein expression in the nucleus to trophinin expression in tumor. HMGB1 and its ligand RAGE (the receptor for advanced glycation end product) proteins were coexpressed in 65.6% of trophinin‐positive patients (n = 32). These results suggest that trophinin promotes invasion through a mechanism involving HMGB1/RAGE. © 2007 Wiley‐Liss, Inc.
Response of Aquatic Leaf Associated Microbial Communities to Elevated Leachate DOC: A Microcosm Study
Authors: Schlief Jeanette , Mutz Michael
Published: May 2007

In Central Europe climate change will increase summer droughts, which cause both, premature leaf fall and fragmentation of small streams during summer and early autumn. As a consequence dissolved organic carbon (DOC) leached from leaves will be dispersed into pools with long water residence time. A microcosm experiment was performed to test the effect of high concentrations of leachate DOC and the relative importance of labile and refractory leachate compounds on leaf associated microbial parameters. In microcosms leaf discs colonized in a stream were exposed to high concentrations of either leaf leachate, glucose or tannic acid. Leaf associated respiration, fungal sporulation, leaf mass loss and fungal biomass (ergosterol) were measured during a 3 weeks experimental period and compared to control without DOC amendment. The results imply that depending on source and composition elevated leachate DOC may have variable effects on microbial mediated litter decomposition. Our findings suggest reduced microbial decomposition rates in pools of fragmented streams receiving premature leaf fall. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detritus Processing in Tri‐Trophic Food Chains: a Modelling Approach
Authors: Alemanno Sara , Mancinelli Giorgio , Basset Alberto
Published: May 2007

We present a model describing the fluxes of matter and energy through a detritus‐based aquatic community. The model is based on the investigation of the decomposition of Phragmites australis in a Southern Italian coastal lagoon (Lake Alimini Grande). It reproduces the behaviour of the detritus‐based system by simulating processes of microbial growth and macroinvertebrate colonization in a specific patch of detritus. Specifically, the macroinvertebrate colonization is seen as a dynamic process in which individuals move towards the patch according to resource availability. The good agreement between simulated and experimental data suggests that the behaviourally‐based mechanism of invertebrate colonization characterising our model provides an effective description of the decomposition patterns observed in nature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Drought Frequency and Other Reach Characteristics on Invertebrate Communities and Litter Breakdown in the Intermittent Mediterranean River Pula (Sardinia, Italy)
Authors: Sangiorgio Franca , Fonnesu Alessio , Mancinelli Giorgio
Published: May 2007

Benthic invertebrate communities were sampled in spring and fall, and breakdown of reed litter was measured in winter, spring, summer and fall, at 23 sites in an intermittent Mediterranean river basin (Pula, Sardinia, Italy), and their variations were related to drought frequency and other reach characteristics (altitude, order, stream channel width and depth, vegetation cover, sediment type, organic content, and water quality). 78% of the sites were affected by drought events, mainly in summer and fall. Benthic taxonomic richness was higher and most taxa were more widely distributed in spring than in fall. Canonical correspondence analysis showed that measured environmental variables accounted for 72% of the variance in invertebrate community structure. Reed decay rates varied among seasons, and during the dry season among stream orders as well. Drought events slowed down breakdown and explained 44% of spatial variability in decay rates (Stepwise multiple regression analysis), an additional 8% being explained by water chemistry. Results suggest that drought events affect ecosystem functioning (litter breakdown) more than structure (invertebrate communities). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Litter Decomposition of Scirpus maritimus L. in a Mediterranean Coastal Marsh: Importance of the Meiofauna during the Initial Phases of Detached Leaves Decomposition
Authors: Sanmartí Neus , Menéndez Margarita
Published: May 2007

Growth, senescence and decomposition rates of Scirpus maritimus were studied in a Mediterranean brackish wetland. Plant tussocks were tagged in March, 2002 and were totally dead by September, 2002. Decomposition rates were determined over 360 days using litter bag technique and mass loss, nutrient dynamics, fungal biomass, meiofauna and macroorganisms were determined. Decomposition rate of detached S. maritimus litter was 0.00196 (k, day–1) with a 54% of mass lost observed in 1 year. The pattern of mass loss was characterized by an initial phase of fast loss of organic matter with high density of meiofauna and a decrease of oxygen content, followed by two slower phases, with no significant losses from 50 to 180 days and with 21% of mass lost from 180 to 360 days. Nitrogen (N) and phosphorus (P) content of plant litter increased during decomposition process whereas atomic C:N and C:P ratios decreased, suggesting a nutrient immobilization on plant detritus. Fungal biomass measured as ergosterol content decreased after submersion of leaves, indicating that their importance in litter decomoposition decreases in submerged leaves during the first days of decomposition. An inverse relationship (r = –0.79, P < 0.005) was observed between ergosterol content and nematodes density on S. maritimus litter. Our results suggest that in Mediterranean brackish marshes, where large amounts of dead organic matter is accumulated over the sediment surface, decomposition process is greatly affected by extremely high temperatures in summer that, if water is available, accelerates microbial activity decreasing oxygen content thus slowing decomposition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leachates of Eucalyptus globulus in Intermittent Streams Affect Water Parameters and Invertebrates
Authors: Canhoto Cristina , Laranjeira Celia
Published: May 2007

Low order streams running through Eucalyptus globulus plantations in Central Portugal are frequently reduced to isolated permanent or temporary summer pools with darkly stained water due to leaf leachates. Here we assess the toxicity of such leachates to the shredder Sericostoma vittatum. Leachates resulted in deoxygenated and more acid water, and increased its phenolic content and conductivity. S. vittatum exposed to high concentrations of leachates failed to grow and died within 30 days even in the presence of high quality food. Larvae in water with half the leachate concentration, consumed less leaf material, had lower growth rates, did not pupate and died within 100 days. Eucalypt leachates per se may affect the viability and ecology of macroinvertebrates in Portuguese streams. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Invertebrates Colonization on Native Tree Leaves in a Neotropical Stream (Brazil)
Authors: Moretti Marcelo S. , Gonçalves José Francisco , Ligeiro Raphael , Callisto Marcos
Published: May 2007

We evaluate the composition and structure of invertebrate assemblages during leaf breakdown of five native tree species (Myrcia guyanensis, Ocotea sp., Miconia chartacea, Protium brasiliense and Protium heptaphyllum) and a mixture of them in a headwater stream, Southeastern Brazil. Coarse mesh litter bags were used over a 120‐day period. P. heptaphyllum showed the slowest breakdown rate, while Myrcia showed the fastest. Total densities and biomass values of associated invertebrates were different among leaf types and incubation periods. The highest values of total abundance were found in P. heptaphyllum, while Ocotea sp. and Miconia were few colonized. Gathering‐collectors feeding group dominated all leaf types, followed by predators and shredders. Shredders were more abundant in Myrcia than in Miconia and the mixed pack. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Top‐Down Control of Reed Detritus Processing in a Lake Littoral Zone: Experimental Evidence of a Seasonal Compensation between Fish and Invertebrate Predation
Authors: Mancinelli Giorgio , Costantini Maria Letizia , Rossi Loreto
Published: May 2007

We investigated whether predatory fish exert a top‐down control on reed leaf packs processing in a lake littoral zone through a trophic cascade. Exclosure experiments were repeated in summer and winter, under high and low natural fish abundance, respectively.

Fish exclusion effects on detritus processing and fungal conditioning were consistent with trophic cascade predictions only in summer. In winter, however, results indicated that a trophic cascade was induced by predatory invertebrates. In both seasons, variations in detritivores abundance generally supported a cascade scenario, whereas several taxon‐specific departures occurred during the experimental periods. We conclude suggesting that predators may continuously regulate leaf detritus processing in lake littoral zones, through a seasonal shift in the relative contribution of fish and invertebrate predation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A tightly regulated and reversibly inducible siRNA expression system for conditional RNAi‐mediated gene silencing in mammalian cells
Authors: Wu Ren‐Huang , Cheng Tsung‐Lin , Lo San‐Ren , Hsu Hui‐Chun , Hung Chuan‐Fu , Teng Chiao‐Fang , Wu Ming‐Ping , Tsai Wen‐Hui , Chang Wen‐Tsan
Published: May 2007

Background

RNA interference (RNAi) is a powerful and widely used gene silencing strategy for studying gene function in mammalian cells. Transient or constitutive expression of either small interfering RNA (siRNA) or short hairpin RNA (shRNA) results in temporal or persistent inhibition of gene expression, respectively. A tightly regulated and reversibly inducible RNAi‐mediated gene silencing approach could conditionally control gene expression in a temporal or spatial manner that provides an extremely useful tool for studying gene function involved in cell growth, survival and development.

Material and methods

In this study, we have developed a lactose analog isopropyl thiogalactose (IPTG)‐responsive lac repressor‐operator‐controlled RNA polymerase III (Pol III)‐dependent human RNase P RNA (H1) promoter‐driven inducible siRNA expression system. To demonstrate its tight regulation, efficient induction and reversible inhibition, we have used this system to conditionally control the expression of firefly luciferase and human tumor suppressor protein p53 in both transient transfection cells and established stable clones.

Results

The results showed that this inducible siRNA expression system could efficiently induce conditional inhibition of these two genes in a dose‐ and time‐dependent manner by administration of the inducing agent IPTG as well as being fully reverted after withdrawal of IPTG. In particular, this system could conditionally inhibit the expression of both the genes in not only established stable clones but also transient transfection cells, which should greatly increase its usefulness and convenience.

Conclusions

The results presented in this study clearly indicate that this inducible siRNA expression system could efficiently, conditionally and reversibly inhibit gene expression with only very low or undetectable background silencing effects under non‐inducing condition. Thus, this inducible siRNA expression system provides an ideal genetic switcher allowing the inducible and reversible control of specific gene activity in mammalian cells. Copyright © 2007 John Wiley & Sons, Ltd.
Recognized sequence and conformation in design of linear peptides as a competitive inhibitor for HMG‐CoA reductase
Authors: Pak Valeriy V. , Koo Minseon , Yun Lyubov , Kwon Dae Young
Published: May 2007

This study is an attempt to develop a simple search method for lead peptide candidates, which include constrained structures in a recognized sequence, using the design of a competitive inhibitor for HMG‐CoA reductase (HMGR). A structure‐functional analysis of previously synthesized peptides proposes that a competitive inhibitory peptide can be designed by maintaining bioactive conformation in a recognized sequence. A conformational aspect of the structure‐based approach was applied to the peptide design. By analysis of the projections obtained through a principle component analysis (PCA) for short linear and cyclic peptides, a head‐to‐tail peptide cycle is considered as a model for its linear analogy. It is proposed that activities of the linear peptides based on an identical amino acid sequence, which are obtained from a less flexible peptide cycle, would be relatively higher than those obtained from more flexible cyclic peptides. The design criterion was formulated in terms of a ‘V’ parameter, reflecting a relative deviation of an individual peptide cycle from an average statistical peptide cycle based on all optimized structures of the cyclic peptides in set. Twelve peptide cycles were selected for the peptide library. Comparing the calculated ‘V’ parameters, two cyclic peptides (GLPTGG and GFPTGG) were selected as lead cycles from the library. Based on these sequences, six linear peptides obtained by breaking the cycle at different positions were selected as lead peptide candidates. The linear GFPTGG peptide, showing the highest inhibitory activity against HMGR, increases the inhibitory potency nearly tenfold. Kinetic analysis reveals that the GFPTGG peptide is a competitive inhibitor of HMG‐CoA with an equilibrium constant of inhibitor binding (Ki) of 6.4 ± 0.3 µM. Conformational data support a conformation of the designed peptides close to the bioactive conformation of the previously synthesized active peptides. Copyright © 2007 John Wiley & Sons, Ltd.
A new testing method for vital gluten swelling index
Authors: Hu XinZhong , Shang YaNing
Published: May 2007

Vital gluten is a kind of functional protein, but currently its quality indices are mostly focused on the outer character rather than the inner content. The objective of this study was to develop an improved testing method for the measurement of vital gluten, reported here as the vital gluten swelling index (VGSI). The procedures were optimized using the vital gluten water absorption ratio and the wheat flour protein fraction content. The following procedure is recommended: use 0.9 mL distilled water to hydrate 20 mg vital gluten for 10 min, and then add 0.9 mL of 0.03 g kg−1 sodium dodecyl sulfate–lactic acid solution and mix for another 30 min. Finally, centrifuge the mixture at 5000 × g and measure the residue weight. The quality of vital gluten can be simply classified by its swelling index value. A VGSI of ≥ 28% indicates vital gluten of superior grade, between 24% and 28% is a good grade, while ≤24% is an inferior grade. Compared with the laborious method of vital gluten water absorption (VGWA), which takes a relatively long time to test one sample, VGSI requires only 47 min to test 24 samples. Further, the VGSI method is more accurate, reliable and repeatable. The coefficient of variation of VGWA of the vital gluten samples is 2.09, while the corresponding value for VGSI was 14.83. The correlation coefficients between VGSI and other vital gluten indices were significant. The research indicates that the method developed is the best to evaluate vital gluten. Copyright © 2007 Society of Chemical Industry
The impact of cold temperatures during grain maturation on selected quality parameters of wheat
Authors: Craven Maryke , Barnard Annelie , Labuschagne Maryke T
Published: May 2007

The influence of sudden cold spells during grain filling of wheat on the quality traits of three South African hard red wheat cultivars (Gariep, Elands and Tugela‐DN) was studied, with the emphasis on Hagberg falling number (HFN). Four treatments were used (−1 °C at soft dough stage, − 1 °C at late milk stage, − 4 °C at soft dough stage and − 4 °C at late milk stage) and were administered for one night only. From the results it was concluded that, although limited in duration, such frost conditions did have an effect on the quality of the wheat cultivars. Cultivars differed in their response to the various treatments but also as to what quality traits were affected the most. The − 4 °C at late milk stage resulted in significantly reduced HFN being measured for both Elands and Tugela‐DN. A similar effect was observed for Gariep, but was not statistically significant. Although the response was limited to the main tillers only, the conclusion was made that it is probable that the reduced HFN would be visible in the pooled sample of head and side tillers. A screening protocol was suggested that would allow classification of cultivars for frost tolerance. Copyright © 2007 Society of Chemical Industry
On a semilinear elliptic equation with singular term and Hardy–Sobolev critical growth
Authors: Chen Jianqing
Published: May 2007

In a previous work [6], we got an exact local behavior to the positive solutions of an elliptic equation. With the help of this exact local behavior, we obtain in this paper the existence of solutions of an equation with Hardy–Sobolev critical growth and singular term by using variational methods. The result obtained here, even in a particular case, relates with a partial (positive) answer to an open problem proposed in: A. Ferrero and F. Gazzola, Existence of solutions for singular critical growth semilinear elliptic equations, J. Differential Equations 177, 494–522 (2001). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the decay of the solutions of second order parabolic equations with Dirichlet conditions
Authors: Franke Brice
Published: May 2007

We use rearrangement techniques to investigate the decay of the parabolic Dirichlet problem in a bounded domain. The coefficients of the second order term are used to introduce an isoperimetric problem. The resulting isoperimetric function together with the divergence of the first order coefficients and the value distribution of the zero order part are then used to construct a symmetric comparison equation having a slower heat‐flow than the original equation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Régularisation et $ \bar \partial_b $ homotopie sur les variétés CR
Authors: Sambou Salomon
Published: May 2007

On donne un résultat de régularisation et $ \bar \partial_b $‐homotopie sur les variétés CR génériques. On en déduit des théorèmes d'isomorphisme entre groupes de $ \bar \partial_b $ cohomologie.

Ce résultat généralise un travail de Chirka obtenu sur les variétés complexes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A multifractal decomposition according to rate of returns
Authors: Ma Jihua , Wen Zhiying
Published: May 2007

For one‐dimensional simple symmetric random walk, the Hausdorff and packing dimensions of sets of sample paths with prescribed rate of returns to the origin are determined. This gives a multifractal decomposition of the underlying sample space. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resolvent estimates in W−1,p related to strongly coupled‐linear parabolic systems with coupled nonsmooth capacities
Authors: Glitzky Annegret , Hünlich Rolf
Published: May 2007

We investigate linear parabolic systems with coupled nonsmooth capacities and mixed boundary conditions. We prove generalized resolvent estimates in W−1, p spaces. The method is an appropriate modification of a technique introduced by Agmon to obtain Lp estimates for resolvents of elliptic differential operators in the case of smooth boundary conditions. Moreover, we establish an existence and uniqueness result. Copyright © 2007 John Wiley & Sons, Ltd.