A sensitivity study for the visualisation of bacterial weathering of concrete and stone with computerised X-ray microtomography

Geologists and engineers recently have adopted computerised X-ray microtomography (microCT), a radiological imaging technique, for geological and petrophysical applications such as the assessment of sediment characteristics, CT-measurement of compressibility and compaction, multiphase flow studies, measurement of bulk density and moisture content, and of porosity and permeability. This study focuses on another application: the monitoring of biological weathering of natural building stones and concrete. Microbial activity as a determining factor in the deterioration process of building materials has a major economic impact. Because of its non-destructive character, microCT could be the ideal monitoring technique. With this technique, three-dimensional (3D) images of the entire inner structure of the material can be obtained, together with quantitative data. In depth changes of porosity of concrete and stone specimens due to bacterial weathering were assessed in this work. Also, porosity was visualised based on 3D data with homemade software. Scanning electron microscopy (SEM) images provided additional information and supported conclusions drawn from the X-ray microCT data. Resolution improvement will make the study of petrophysical aspects of physical weathering and/or biological deterioration processes of natural building stones and concrete a promising subject for further microCT-application.

Lay health workers in primary and community health care

BACKGROUND

Lay health workers (LHWs) are widely used to provide care for a broad range of health issues. However, little is known about the effectiveness of LHW interventions.

OBJECTIVES

To assess the effects of LHW interventions in primary and community health care on health care behaviours, patients' health and wellbeing, and patients' satisfaction with care.

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care and Consumers and Communication specialised registers (to August 2001); the Cochrane Central Register of Controlled Trials (to August 2001); MEDLINE (1966- August 2001); EMBASE (1966-August 2001); Science Citations (to August 2001); CINAHL (1966-June 2001); Healthstar (1975-2000); AMED (1966-August 2001); the Leeds Health Education Effectiveness Database and the reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials of any intervention delivered by LHWs (paid or voluntary) in primary or community health care and intended to promote health, manage illness or provide support to patients. A 'lay health worker' was defined as any health worker carrying out functions related to health care delivery; trained in some way in the context of the intervention; and having no formal professional or paraprofessional certificated or degreed tertiary education. There were no restrictions on the types of consumers.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data onto a standard form and assessed study quality. Studies that compared broadly similar types of interventions were grouped together. Where feasible, the results of included studies were combined and an estimate of effect obtained.

MAIN RESULTS

Forty three studies met the inclusion criteria, involving more than 210,110 consumers. These showed considerable diversity in the targeted health issue and the aims, content and outcomes of interventions. Most were conducted in high income countries (n=35), but nearly half of these focused on low income and minority populations (n=15). Study diversity limited meta-analysis to outcomes for five subgroups (n=15 studies) (LHW interventions to promote the uptake of breast cancer screening, immunisation and breastfeeding promotion [before two weeks and between two weeks and six months post partum] and to improve diagnosis and treatment for selected infectious diseases). Promising benefits in comparison with usual care were shown for LHW interventions to promote immunisation uptake in children and adults (RR=1.30 [95% CI 1.14, 1.48] p=0.0001) and LHW interventions to improve outcomes for selected infectious diseases (RR=0.74 [95% CI 0.58, 0.93) p=0.01). LHWs also appear promising for breastfeeding promotion. They appear to have a small effect in promoting breast cancer screening uptake when compared with usual care. For the remaining subgroups (n=29 studies), the outcomes were too diverse to allow statistical pooling. We can therefore draw no general conclusions on the effectiveness of these subgroups of interventions.

AUTHORS' CONCLUSIONS

LHWs show promising benefits in promoting immunisation uptake and improving outcomes for acute respiratory infections and malaria, when compared to usual care. For other health issues, evidence is insufficient to justify recommendations for policy and practice. There is also insufficient evidence to assess which LHW training or intervention strategies are likely to be most effective. Further research is needed in these areas.

Non spiral and spiral (helical) flow patterns in stenoses. In vitro observations using spin and gradient echo magnetic resonance imaging (MRI) and computational fluid dynamic modeling

AIM

Physiological blood flow patterns are themselves poorly understood despite their impact on arterial disease. Stable spiral (helical) laminar flow (SLF) has been observed in normal subjects. The purpose of the present study is to develop a method of magnetic resonance (MR) flow pattern visualization and to analyze spiral and non-spiral flow patterns with and without luminal narrowing in vitro. The flow conditions were then modeled using computational fluid dynamics (Star-CD).

METHODS

Laminar integrity was examined in a flow-rig using spin and gradient echo magnetic resonance imaging (MRI) in non-stenosed and stenosed conduits in the presence of non-spiral and spiral flow.

RESULTS

No difference was observed in a non-stenosed conduit between non-spiral and spiral flow. In the presence of a stenosis spiral flow preserves flow velocity coherence whereas non-spiral flow increasingly lost coherence beginning proximal to the stenosis. Computational fluid dynamic modeling of the in vitro experiment showed marked differences between the 2 flow patterns. Non-spiral flow produced greater inwardly directed forces just beyond the stenosis and greater outward pressures at more distal sites. The near wall turbulent energy was up to 700% less with spiral flow over non-spiral flow beyond the stenosis.

CONCLUSIONS

Spiral flow appears to offer clear flow profile stabilizing advantages over non-spiral flow, by significantly reducing the turbulence caused by a stenosis. Spiral flow also produces lower forces acting on the vessel wall.

DOTS for temporary workers in the agricultural sector. An exploratory study in Tuberculosis case detection

This study was conducted in the Boland health district of the Cape Winelands of South Africa where there is a high tuberculosis incidence and prevalence. A survey conducted on 211 farms in the study district during 1998, reported that 65% (n = 9042) of all workers on these farms, were temporarily employed. Temporary farm workers live in communities either within or on the outskirts of the boundaries of the Boland health district, from where they are transported to work daily.

Evolution of a vancomycin-intermediate Staphylococcus aureus strain in vivo: multiple changes in the antibiotic resistance phenotypes of a single lineage of methicillin-resistant S. aureus under the impact of antibiotics administered for chemotherapy

A number of methicillin-resistant Staphylococcus aureus (MRSA) isolates were recovered over a period of several weeks from blood samples and from the heart valve of a patient who underwent extensive vancomycin chemotherapy for persistent S. aureus bacteremia. Consecutive isolates showed gradually decreasing growth rates during in vitro cultivation and increasing vancomycin MICs, from an MIC of 1 micro g/ml for the initial isolate to an MIC of 8 micro g/ml for the final MRSA isolates, which also became tolerant to vancomycin. Major changes were observed in the oxacillin resistance phenotype of several of the isolates-apparently related to in vivo exposure to imipenem, which was also used during a period of chemotherapy. Both the gradually increasing vancomycin MICs and the changes in oxacillin resistance could be reproduced by appropriate exposure of the initial MRSA isolate to antibiotics in vitro. All isolates had the same pulsed-field gel electrophoresis pattern, spaA type, and multilocus sequence type (MLST), which was identified as a single-locus variant of ST5, the MLST characteristic of previously characterized MRSA isolates with reduced susceptibility to vancomycin in the United States and Japan.

An exploration of the concept of directly observed treatment (DOT) for tuberculosis patients: from a uniform to a customised approach

Tuberculosis (TB) management has moved from chaotic systems and low patient adherence with treatment regimens to the directly observed therapy, short course (DOTS) strategy, which has been described as a new paradigm of TB control. Directly observed treatment (DOT) is only one component of the full DOTS strategy. DOT versus self-administered treatment (SAT) has been the subject of extensive debate, particularly about what approach improves treatment adherence. This debate has been complicated by different case-holding rates and cure outcomes in different contexts where DOT is in place. The increasing range of DOT applications in different settings, including the choice of provider, place, target population, and the extent to which DOT is part of a wider approach, has not been sufficiently taken into account. However, the concrete reality of DOT is an important determinant of the overall success or failure of the programme, and has implications in terms of equity and accessibility of care during treatment. This article aims to go beyond the frequently polarised debate of DOT versus SAT and document the diversity of ways in which DOT has been implemented internationally. We also aim to raise key issues for further discussion, including 1) viewing DOT as part of a complex and lengthy set of interventions that are context-specific, 2) incorporating an equity approach that discusses individual patients' needs and the relationship between the patient and provider, and 3) the role of incentives and enablers. It is anticipated that this exchange of opinion and experiences from different parts of the world will be useful for those involved in the policy formulation and practice of TB management.

Deficiency in parvalbumin increases fatigue resistance in fast-twitch muscle and upregulates mitochondria

The soluble Ca2+-binding protein parvalbumin (PV) is expressed at high levels in fast-twitch muscles of mice. Deficiency of PV in knockout mice (PV -/-) slows down the speed of twitch relaxation, while maximum force generated during tetanic contraction is unaltered. We observed that PV-deficient fast-twitch muscles were significantly more resistant to fatigue than were the wild type. Thus components involved in Ca2+ homeostasis during the contraction-relaxation cycle were analyzed. No upregulation of another cytosolic Ca2+-binding protein was found. Mitochondria are thought to play a physiological role during muscle relaxation and were thus analyzed. The fractional volume of mitochondria in the fast-twitch muscle extensor digitorum longus (EDL) was almost doubled in PV -/- mice, and this was reflected in an increase of cytochrome c oxidase. A faster removal of intracellular Ca2+ concentration ([Ca2+]i) 200-700 ms after fast-twitch muscle stimulation observed in PV -/- muscles supports the role for mitochondria in late [Ca2+]i removal. The present results also show a significant increase of the density of capillaries in EDL muscles of PV -/- mice. Thus alterations in the dynamics of Ca2+ transients detected in fast-twitch muscles of PV -/- mice might be linked to the increase in mitochondria volume and capillary density, which contribute to the greater fatigue resistance of these muscles.

Interventions for providers to promote a patient-centred approach in clinical consultations

BACKGROUND

Communication problems in health care may arise as a result of health care providers focusing on diseases and their management, rather than people, their lives and their health problems. Patient-centred approaches to care are increasingly advocated by consumers and clinicians and incorporated into training for health care providers. The effects of interventions that aim to promote patient-centred care need to be evaluated.

OBJECTIVES

To assess the effects of interventions for health care providers that aim to promote patient-centred approaches in clinical consultations.

SEARCH STRATEGY

We searched Medline (1966 - Dec 1999); Health Star (1975 - Dec 1999); PsycLit (1887- Dec 1999); Cinahl (1982 - Dec 1999); Embase (1985-Dec 1999) and the bibliographies of studies assessed for inclusion.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials, controlled before and after studies, and interrupted time series studies of interventions for health care providers that promote patient-centred care in clinical consultations. Patient-centred care was defined as a philosophy of care that encourages: (a) shared control of the consultation, decisions about interventions or management of the health problems with the patient, and/or (b) a focus in the consultation on the patient as a whole person who has individual preferences situated within social contexts (in contrast to a focus in the consultation on a body part or disease). The participants were health care providers, including those in training.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data onto a standard form and assessed study quality for each study. We extracted all outcomes other than health care providers' knowledge, attitudes and intentions.

MAIN RESULTS

17 studies met the inclusion criteria. These studies display considerable heterogeneity in terms of the interventions themselves, the health problems or health concerns on which the interventions focused, the comparisons made and the outcomes assessed. All included studies used training for health care providers as an element of the intervention. Ten studies evaluated training for providers only, while the remaining studies utilised multi-faceted interventions where training for providers was one of several components. The health care providers were mainly primary care physicians (general practitioners or family doctors) practising in community or hospital outpatient settings. In two studies, the providers also included nurses. There is fairly strong evidence to suggest that some interventions to promote patient-centred care in clinical consultations may lead to significant increases in the patient centredness of consultation processes. 12 of the 14 studies that assessed consultation processes showed improvements in some of these outcomes. There is also some evidence that training health care providers in patient-centred approaches may impact positively on patient satisfaction with care. Of the eleven studies that assessed patient satisfaction, six demonstrated significant differences in favour of the intervention group on one or more measures. Few studies examined health care behaviour or health status outcomes.

REVIEWER'S CONCLUSIONS

Interventions to promote patient-centred care within clinical consultations may significantly increase the patient centredness of care. However, there is limited and mixed evidence on the effects of such interventions on patient health care behaviours or health status; or on whether these interventions might be applicable to providers other than physicians. Further research is needed in these areas.

Ambivalence of primary health care professionals towards the South African guidelines for hypertension and diabetes

BACKGROUND

Consensus-derived guidelines for hypertension and diabetes management were introduced by the National Department of Health to improve quality of care. However, the incorporation of guidelines into clinical practice is largely dependent on the attitudes of health professionals.

OBJECTIVE

To audit the responses and examine the attitudes of health professionals in primary care towards the diabetes and hypertension care guidelines.

DESIGN

Qualitative focus group, in-depth discussions and clinic observations.

SETTING

Four community health centres (CHCs) in the Western Cape.

SUBJECTS

Fifteen doctors and 10 professional nurses.

METHODS

The responses of health professionals to the guidelines were audited. Their attitudes were evaluated at a single pilot CHC using focus group discussions and in-depth interviews. Semi-structured interviews based on these themes were conducted at 3 other CHCs. Clinic consultations were observed to validate the responses.

RESULTS

The guidelines were not systematically implemented at local CHCs and individual doctors consulted the guidelines infrequently. Several themes were identified as barriers to the application of the guidelines, including the consultation process by which the guidelines were developed, time constraints, scepticism about durability of the guidelines, conflict with local practices, health system problems, and patient beliefs.

CONCLUSION

The usefulness of passive dissemination of guidelines to health professionals in primary care should be reviewed as several attitudinal barriers to implementation may exist. Guidelines may be adopted more readily if these barriers are addressed.

Acute meningococcaemia complicated by late onset gastrointestinal vasculitis

Extra-meningeal and non-cutaneous manifestations of meningococcal infection are well recognized but rare. Herein we report a little recognized complication of meningococcaemia, namely late-onset gastrointestinal vasculitis. In the case presented, the prostacycline analogue iloprost was used in an attempt to minimize incipient digital gangrene ina patient with evidence of protracted immunological phenomena. In addition, diclofenac was used to treat severe arthralgia. Withdrawal of iloprost on day 19 was associated with abdominal pain and peritonism. Laparotomy demonstrated ischaemia and ulceration in the caecum, and histology revealed full thickness mucosal ulceration with a prominent vasculitic process. It is postulated that these findings were immunologically mediated, with possible rebound vasoconstriction following withdrawal of iloprost. It is also possible that NSAID use contributed to the findings via cyto-toxicity to mucosal cells.

A structured record to implement the national guidelines for diabetes and hypertension care

BACKGROUND

Guidelines to improve standards of care for hypertension and diabetes were disseminated by the National Department of Health in 1996 but have generally not been implemented by health professional in local primary care. A strategy for the adoption and implementation of the Guidelines was developed in collaboration with health professionals in primary care.

OBJECTIVES

The development of a structured record, with prompts for the management of diabetes and hypertension according to the Guidelines.

SETTING

Three community health centres (CHCs) in the Western Cape.

PARTICIPANTS

Doctors and nurses managing patients with diabetes and hypertension.

METHODS

A draft of the structured record was developed at a single-pilot CHC in the Western Cape. Focus group discussions established the core requirements for a structured record. Process, result and structural indicators in line with the national Guidelines were considered for inclusion in the draft record. This draft record was then piloted at two other CHCs. Comments from semi-structured interviews and pre- and post-test evaluation questionnaires were used to compile the final instrument.

RESULTS

Eleven doctors and 8 nurses participated in the development of the final instrument. Important considerations in the design were a single-page, user-friendly format, tick-boxes to reduce writing, prompts, provision for sequential recording, target setting, and compatibility with the Guidelines. The final instrument was piloted and elicited a favourable overall response.

CONCLUSION

The structured record simplifies the application of the Guidelines and the systematic recording of processes of care. The effectiveness of the Guidelines will be evaluated further in a randomised control trial using the structured record.

An outbreak of vancomycin-dependent Enterococcus faecium in a bone marrow transplant unit

Outbreaks of vancomycin-resistant enterococci (VRE) are well described. The presence of mutants of VRE, such as vancomycin-dependent enterococci (VDE), in individual patients has been documented, but their potential to spread nosocomially has not been known. We present the first cluster of patients who acquired VDE nosocomially. Five bone marrow transplantation patients were infected or colonized by a genotypically indistinguishable multiantibiotic-resistant strain of Enterococcus faecium. Vancomycin dependence in 3 of the 5 isolates was demonstrated. All cluster patients had received protracted prophylactic treatment with vancomycin (mean, 22.6 days), and specimens from >/=2 body sites were repeatedly culture-positive for the outbreak strain. The outbreak was controlled with aggressive infection control strategies, and prophylactic antibiotic policies were revised. Awareness of the potential for nosocomial spread of multiantibiotic-resistant VDE is vital for the care of immunocompromised patients, especially those receiving prophylactic antibiotics.

Perceptions of overweight African women about acceptable body size of women and children

PURPOSE

Malnutrition, presenting as obesity in women and under-nutrition in children, is a prevalent problem in the squatter communities of Cape Town. Food habits are determined by a complex matrix of economic, social and cultural factors which need to be understood by health professionals prior to the implementation of strategies to improve the nutritional status of this community. This qualitative study is designed to explore the perceptions of overweight black women in Cape Town, with underweight infants, about the culturally acceptable body size for women and children.

METHOD

Qualitative in-depth interviews were conducted with 10 overweight black women who were resident in the metropolitan area of Khayelitsha in Cape Town. A snowballing technique was utilised to select the key informants, all of whom were mothers of underweight infants. The interviews were conducted in Xhosa and recorded, with the permission of participants, onto tape. They were then transcribed and translated into English. The transcripts were coded and analysed by two researchers who worked independently to ensure content validity.

RESULTS

The informants came from disadvantaged communities in which food was highly valued as a result of the fact that food security was not assured. The concept of an individual voluntarily regulating the intake of nutrients when food did become available, appeared unacceptable to the informants. It was not clear from the interviews how the participants perceived their normal or "desired" body weight. Increased body mass was regarded as a token of well-being in that marital harmony was perceived to be reflected in increased body weight. Overweight children were regarded as reflecting health as it was associated with sufficient food supply and intake.

CONCLUSIONS

Although women expressed the desire to loose some excess weight for practical reasons, there was no negative social pressure to motivate this. The attitudes recorded from this qualitative research project suggest cultural perceptions of excess body weight that will complicate the design of effective health promotion strategies to normalise and maintain ideal body weight in this group of African women.

Prolonged contraction-relaxation cycle of fast-twitch muscles in parvalbumin knockout mice

The calcium-binding protein parvalbumin (PV) occurs at high concentrations in fast-contracting vertebrate muscle fibers. Its putative role in facilitating the rapid relaxation of mammalian fast-twitch muscle fibers by acting as a temporary buffer for Ca2+ is still controversial. We generated knockout mice for PV (PV -/-) and compared the Ca2+ transients and the dynamics of contraction of their muscles with those from heterozygous (PV +/-) and wild-type (WT) mice. In the muscles of PV-deficient mice, the decay of intracellular Ca2+ concentration ([Ca2+]i) after 20-ms stimulation was slower compared with WT mice and led to a prolongation of the time required to attain peak twitch tension and to an extension of the half-relaxation time. The integral [Ca2+]i in muscle fibers of PV -/- mice was higher and consequently the force generated during a single twitch was approximately 40% greater than in PV +/- and WT animals. Acceleration of the contraction-relaxation cycle of fast-twitch muscle fibers by PV may confer an advantage in the performance of rapid, phasic movements.

Risk factors and clinical impact of central line infections in the surgical intensive care unit

OBJECTIVE

To determine the risk factors and clinical impact of central line infections in critically ill surgical patients.

DESIGN

Retrospective study.

SETTING

The surgical intensive care unit of a large tertiary care university hospital.

PATIENTS

A total of 232 consecutive central line catheters sent for culture from patients in a surgical intensive care unit during 1996 and 1997. Catheters were sent for microbiologic analysis when the patient was clinically infected and the central line was a possible source.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Risk factors associated and clinical impact of a positive catheter culture.

RESULTS

Of 232 consecutive catheters from 93 patients sent for microbiologic analysis, 114 catheters (49%) had no growth, 40 (17%) were colonized (<15 colonies), and 78 (34%) were considered infected (> or =15 colonies). Univariate analysis showed that site (internal jugular vs subclavian, P<.001), catheter use (monitoring > dialysis > fluid > nutrition, P=.006), placement in the operating room vs the intensive care unit (P=.02), and placement of a new catheter (> guide wire, > new site, P=.003) were all significant factors. Surprisingly, neither the number of lunmens nor the duration of the catheter in situ were predictors when a catheter was suspected and not proved infected compared with a suspected and proved catheter infection. In the multiple regression model, the placement of the catheter in the internal jugular position was the single most important predictor of a catheter infection (P<.001; odds ratio, 1.83; 95% confidence interval [CI], 1.41-2.37). The presence or absence of a specific clinical sign of infection was not predictive of a proved catheter infection. Eighty-six percent of patients had gram-positive bacteria identified on the culture, while the remaining patients had gram-negative bacteria or Candida identified. Of the catheter infections, 68% were monomicrobial, whereas 32% were polymicrobial. Of the catheters sent for microbiologic analysis, 209 (90%) had concurrent peripheral blood cultures for analysis. Nineteen (32%) with no growth from the catheter, and 14 (23%) of colonized catheters had concurrent bacteremia; all had another identifiable cause of infection. Twenty-seven (45%) of infected catheters had a concurrent bacteremia, and 9 of 27 had a second site positive for the same organism. Death related to the infection occurred in 15 patients, 2 in the first 72 hours and 13 in the following 14 days.

CONCLUSIONS

Central line infections remain an important cause of morbidity and mortality. Comprehensive review of hospital practices may show a directed focus for performance improvement practices. At our institution, internal jugular catheters have the highest rate of infection. This may suggest breaks in technique during catheter insertion or during catheter maintenance and care.

CREB-2, a cellular CRE-dependent transcription repressor, functions in association with Tax as an activator of the human T-cell leukemia virus type 1 promoter

The Tax protein of the human T-cell leukemia virus type 1 (HTLV-1) has been implicated in human T-cell immortalization. The primary function of Tax is to transcriptionally activate the HTLV-1 promoter, but Tax is also known to stimulate expression of cellular genes. It has been reported to associate with several transcription factors, as well as proteins not involved in transcription. To better characterize potential cellular targets of Tax present in infected cells, a Saccharomyces cerevisiae two-hybrid screening was performed with a cDNA library constructed from the HTLV-1-infected MT2 cell line. From this study, we found 158 positive clones representing seven different cDNAs. We focused our attention on the cDNA encoding the transcription factor CREB-2. CREB-2 is an unconventional member of the ATF/CREB family in that it lacks a protein kinase A (PKA) phosphorylation site and has been reported to negatively regulate transcription from the cyclic AMP response element of the human enkephalin promoter. In this study, we demonstrate that CREB-2 cooperates with Tax to enhance viral transcription and that its basic-leucine zipper C-terminal domain is required for both in vitro and in vivo interactions with Tax. Our results confirm that the activation of the HTLV-1 promoter through Tax and factors of the ATF/CREB family is PKA independent.

'Dysphagia Severity Score' system: clinical outcomes in paediatric dysphagia

Clinical evaluation and analysis of therapeutic intervention, by means of a user-friendly outcome measure system, is essential in the management of a paediatric dysphagia caseload. The objective of this study was to design a Dysphagia Severity Score (DSS) system and to evaluate its usefulness in profiling dysphagia outcomes. Clinical outcome data, based on ten clinical parameters describing dysphagic status pre- and post-intervention, were collated for 23 concurrent cases and recorded on a data base. Results indicate that all subjects scored an improvement in DSS percentage post-intervention, with an average improvement of 21%. Dysphagia Severity Score profiles are presented for two patients and the limitations and applications are discussed.