Systematic review and quality assessment of clinical and economic evidence for superabsorbent wound dressings in a population with chronic ulcers

Effective exudate management is key for optimal ulcer healing. Superabsorbent dressings are designed to have high fluid handling capacity, reduced risk of exudate leakage, fluid retention under compression, and to sequester harmful exudate components. This study aimed to systematically identify existing evidence for the clinical efficacy and cost-effectiveness of superabsorbent dressings for the treatment of moderate-to-highly exudating chronic ulcers of various etiologies. The aim is focused on examining the 'class' effect of all superabsorbers, not any particular dressing. Clinical and cost effectiveness systematic reviews were conducted, searching Embase, MEDLINE, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature. The Cost Effectiveness Analysis Registry and Econ papers were also searched for the economic review. Outcomes of interest included ulcer closure, dressing properties, hospital- and infection-related outcomes, safety, and economic outcomes. Fourteen studies were included in the clinical systematic review. Eleven were case series, with one randomised controlled trial, one retrospective matched observational study, and one retrospective cohort study. The studies investigated eight superabsorbent dressings and were heterogeneous in their patient population and outcomes. Superabsorbent dressings may result in favourable outcomes, including reductions in frequency of dressing change and pain scores. As most studies were case series, drawing firm conclusions was difficult due to absence of a comparator arm. The economic systematic review identified seven studies, five of which were cost-utility analyses. These suggested superabsorbent dressings are a more cost-effective option for the treatment of chronic ulcers compared with standard dressings. However, the small number and low quality of studies identified in both reviews highlights the need for future research.

Prognostic models for clinical outcomes in patients with venous leg ulcers: A systematic review

OBJECTIVE

The purpose of this review was to identify prognostic models for clinical application in patients with venous leg ulcers (VLUs).

METHODS

Literature searches were conducted in Embase, Medline, Cochrane, and CINAHL databases from inception to December 22, 2021. Eligible studies reported prognostic models aimed at developing, validating, and adjusting multivariable prognostic models that include multiple prognostic factors combined, and that predicted clinical outcomes. Methodological quality was assessed using the CHARMS checklist and PROBAST short form questionnaire.

RESULTS

Thirteen studies were identified, of which three were validation studies of previously published models, four reported derivation and validation of models, and the remainder reported derivation models only. There was substantial heterogeneity in the model characteristics, including 11 studies focused on wound healing outcomes reporting 91 different predictors. Three studies shared similar predicted outcomes, follow-up timepoint and used a Cox proportional hazards model. However, these models reported different predictor selection methods and different predictors and it was therefore not feasible to summarize performance, such as discriminative ability.

CONCLUSIONS

There are no standout risk prediction models in the literature with promising clinical application for patients with VLUs. Future research should focus on developing and validating high-performing models in wider VLU populations.

High-protein home parenteral nutrition in malnourished oncology patients: a systematic literature review

INTRODUCTION

Up to 83% of oncology patients are affected by cancer-related malnutrition, depending on tumour location and patient age. Parenteral nutrition can be used to manage malnutrition, but there is no clear consensus as to the optimal protein dosage. The objective of this systematic literature review (SLR) was to identify studies on malnourished oncology patients receiving home parenteral nutrition (HPN) where protein or amino acid delivery was reported in g/kg bodyweight/day, and to compare outcomes between patients receiving low (< 1 g/kg bodyweight/day), standard (1-1.5 g/kg/day), and high-protein doses (> 1.5 g/kg/day).

METHODS

Literature searches were performed on 5th October 2021 in Embase, MEDLINE, and five Cochrane Library and Centre for Reviews and Dissemination databases. Searches were complemented by hand-searching of conference proceedings, a clinical trial registry, and bibliographic reference lists of included studies and relevant SLRs/meta-analyses.

RESULTS

Nineteen publications were included; sixteen investigated standard protein, two reported low protein, and one included both, but none assessed high-protein doses. Only one randomised controlled trial (RCT) was identified; all other studies were observational studies. The only study to compare two protein doses reported significantly greater weight gain in patients receiving 1.15 g/kg/day than those receiving 0.77 g/kg/day.

CONCLUSION

At present, there is insufficient evidence to determine the optimal protein dosage for malnourished oncology patients receiving HPN. Data from non-HPN studies and critically ill patients indicate that high-protein interventions are associated with increased overall survival and quality of life; further studies are needed to establish whether the same applies in malnourished oncology patients.

A plain language summary on preventing fungal infections with isavuconazole in people with blood-related conditions

WHAT IS THIS SUMMARY ABOUT?

People with blood-related conditions have a higher chance of getting invasive fungal infections (IFIs). IFIs are severe fungal infections that can lead to death. Only a few medications, known as antifungals, exist that can be used to prevent IFIs, and sometimes they can cause very bad side effects. Isavuconazole is an antifungal which has been approved to treat IFIs, but it has not been approved to prevent IFIs. In this study, we reviewed published studies that looked at how well isavuconazole prevented IFIs in people who have a higher chance of getting IFIs.

WHAT WERE THE RESULTS?

This review showed that isavuconazole could be effective at preventing IFIs in people with blood-related conditions, as well as being a safe medication.

WHAT DO THE RESULTS OF THE STUDY MEAN?

Isavuconazole can prevent IFIs in people who have a higher chance of getting IFIs. Guidelines should consider that patients need new antifungals to prevent IFIs, and more research needs to be done to see which medicines work best, and which have fewer side effects. Clinical Trial Registration: Please note that 7 studies included in this review were planned studies (1 prospective, 6 retrospective), 2 were real- world studies, 1 of which was registered as a clinical trial NCT03019939 (ClinicalTrials.gov).

Effectiveness and safety of isavuconazole prophylaxis for invasive fungal infections in the haematologic setting

OBJECTIVES

Patients with haematologic malignancies are at high risk of developing invasive fungal infections (IFIs). Current guidelines recommend the use of azoles for IFI prophylaxis; however, in many clinical situations, antifungal prophylaxis is used off-label. We conducted a systematic literature review to provide haematologists with the available evidence on the effectiveness and safety of isavuconazole in IFI prophylaxis in interventional and real-world, observational studies.

METHODS

Embase, MEDLINE and Cochrane Library databases, and relevant conference proceedings and clinical trial registries, were searched for studies on the effectiveness and safety of isavuconazole prophylaxis in adults at high risk of IFIs. Studies were assessed for inclusion and risk of bias.

RESULTS

Nine studies were eligible for inclusion in the review, eight of which were in haematologic populations (patients undergoing haematopoietic stem cell transplantation or with acute myeloid leukaemia or myelodysplastic syndromes; n = 5) or included haematologic populations (n = 3). Evidence from these studies suggests isavuconazole is effective for IFI prophylaxis in the haematologic setting. However, the studies frequently lacked safety data, most were based on small patient populations from single centres and risk of bias could not be assessed for five studies.

DISCUSSION

These findings provide evidence for isavuconazole as an alternative azole for prophylaxis in high-risk populations. Limitations include lack of applicability of risk of bias assessment tools, level of filtering applied in the search strategy and focus on English-language publications.

CONCLUSION

Isavuconazole may be an effective azole for IFI prophylaxis in high-risk haematologic populations, although further studies are needed.

The clinical and cost-effectiveness of supplemental parenteral nutrition in oncology

Background

Clinical guidelines recommend that parenteral nutrition (PN) is added to enteral nutrition (EN; supplemental parenteral nutrition (SPN)) in order to meet energy and protein needs in patients with cancer when EN alone is insufficient. However, although cancer-related malnutrition is common, there is poor awareness of the value of nutritional care, resulting in SPN being chronically underused.

Methods

We performed a targeted literature review and exploratory cost-utility analysis to gather evidence on the clinical effectiveness of SPN, and to estimate the potential cost-effectiveness of SPN versus EN alone in an example cancer setting.

Results

The literature review identified studies linking SPN with malnutrition markers, and studies linking malnutrition markers with clinical outcomes. SPN was linked to improvements in body mass index (BMI), fat-free mass, phase angle (PhA) and prealbumin. Of these markers, BMI and PhA were strong predictors of survival. By combining published data, we generated indirect estimates of the overall survival HR associated with SPN; these ranged from 0.80 to 0.99 (mode 0.87). In patients with Stage IV inoperable pancreatic cancer, the incremental cost-effectiveness ratio versus EN alone was estimated to be £41 350 or £91 501 depending on whether nursing and home delivery costs for EN and SPN were combined or provided separately.

Conclusion

Despite a lack of direct evidence, the results of the literature review demonstrate that SPN may provide important clinical and quality of life benefits to patients with cancer. The potential for any improvement in outcomes in the modelled patient population is very limited, so cost-effectiveness may be greater in patients with less severe disease and other types of cancer.

Evidence-based treatment of multicystic dysplastic kidney: a systematic review

OBJECTIVES

There is a lack of a standardised protocol for the investigation and non-operative management of paediatric multicystic dysplastic kidney (MCDK). Institutional protocols for non-operative management remain essentially ad hoc. The primary outcome of this systematic review is to establish the incidence of hypertension associated with an MCDK. The secondary outcome is to determine the malignancy risk associated with an MCDK. The tertiary outcome is to assess the rate of MCDK involution. Subsequent to these, an evidence-based algorithm for follow-up is described.

METHODOLOGY

A systematic review of all relevant studies published between 1968 and April 2017 was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were identified by specific inclusion and exclusion criteria, all of which included data relevant to the primary, secondary and tertiary outcomes. Hypertension was defined as systolic blood pressure greater than the 95th centile for gender, age and height centile. Subset analysis was performed for hypertension associated with an MCDK.

RESULTS

The primary outcome measure revealed a 3.2% (27/838) risk of developing hypertension associated with an MCDK. The secondary outcome measure noted a 0.07% malignancy risk (2/2820). The tertiary outcome measure established that 53.3% (1502/2820) had evidence of involution of the dysplastic kidney. A total of 44 cohort studies (2820 patients) were analysed.

CONCLUSION

Given the low risk of hypertension and malignancy, which is similar to the general population, the current conservative non-operative pathway is an appropriate management strategy. An algorithm to help support clinicians with ongoing management is proposed.

A randomized controlled trial protocol assessing the effectiveness, safety and cost-effectiveness of methotrexate vs. ciclosporin in the treatment of severe atopic eczema in children: the TREatment of severe Atopic eczema Trial (TREAT)

BACKGROUND

Oral systemic immunomodulatory medication is regularly used off-licence in children with severe atopic eczema. However, there is no firm evidence regarding the effectiveness, safety, cost-effectiveness and impact on quality of life from an adequately powered randomized controlled trial (RCT) using systemic medication in children.

OBJECTIVES

To assess whether there is a difference in the speed of onset, effectiveness, side-effect profile and reduction in flares post-treatment between ciclosporin (CyA) and methotrexate (MTX), and also the cost-effectiveness of the drugs. Treatment impact on quality of life will also be examined in addition to whether FLG genotype influences treatment response. In addition, the trial studies the immune-metabolic effects of CyA and MTX.

METHODS

Multicentre, parallel group, assessor-blind, pragmatic RCT of 36 weeks' duration with a 24-week follow-up period. In total, 102 children aged 2-16 years with moderate-to-severe atopic eczema, unresponsive to topical treatment will be randomized (1 : 1) to receive MTX (0·4 mg kg^-1 per week) or CyA (4 mg kg^-1 per day).

RESULTS

The trial has two primary outcomes: change from baseline to 12 weeks in Objective Severity Scoring of Atopic Dermatitis (o-SCORAD) and time to first significant flare following treatment cessation.

CONCLUSIONS

This trial addresses important therapeutic questions, highlighted in systematic reviews and treatment guidelines for atopic eczema. The trial design is pragmatic to reflect current clinical practice.

A Systematic Literature Review and Network Meta-Analysis Comparing Once-Weekly Semaglutide with Other GLP-1 Receptor Agonists in Patients with Type 2 Diabetes Previously Receiving 1-2 Oral Anti-Diabetic Drugs

INTRODUCTION

Once-weekly semaglutide is a new glucagon-like peptide-1 (GLP-1) analogue administered at a 1.0 or 0.5 mg dose. As head-to-head trials assessing once-weekly semaglutide as an add-on to 1-2 oral anti-diabetic drugs (OADs) vs other GLP-1 receptor agonists (GLP-1 RAs) are limited, a network meta-analysis (NMA) was performed. The objective was to assess the relative efficacy and safety of once-weekly semaglutide vs GLP-1 RAs in patients with type 2 diabetes (T2D) inadequately controlled on 1-2 OADs.

METHODS

A systematic literature review (SLR) was conducted in order to identify trials of GLP-1 RAs in patients inadequately controlled on 1-2 OADs. Data at 24 ± 4 weeks were extracted for efficacy and safety outcomes (feasible for analysis in a NMA), which included the key outcomes of change from baseline in glycated hemoglobin (HbA_1c), systolic blood pressure (SBP), and weight, as well as discontinuation due to adverse events (AEs). Data were synthesized using a NMA and a Bayesian framework.

RESULTS

In total, 26 studies were included across the base case analyses. Once-weekly semaglutide 1.0 mg was associated with significantly greater reductions in HbA_1c and weight vs all GLP-1 RA comparators. Once-weekly semaglutide 0.5 mg also achieved significantly greater reductions in HbA_1c and weight compared with the majority of other GLP-1 RAs. Both doses of once-weekly semaglutide were associated with similar odds of discontinuation due to AEs compared with other GLP-1 RAs.

CONCLUSION

Overall, once-weekly semaglutide 1.0 mg as an add-on to 1-2 OADs is the most efficacious GLP-1 RA in terms of the reduction of HbA_1c and weight from baseline after 6 months of treatment. In addition, the analysis suggests that once-weekly semaglutide is well tolerated and not associated with an increase in discontinuations due to AEs compared with other GLP-1 RAs.

FUNDING

Novo Nordisk.

A Network Meta-Analysis Comparing Semaglutide Once-Weekly with Other GLP-1 Receptor Agonists in Japanese Patients with Type 2 Diabetes

INTRODUCTION

Semaglutide once-weekly (QW) is a novel glucagon-like peptide-1 (GLP-1) analogue administered at a 0.5 or 1.0 mg dose. In the absence of head-to-head trials between semaglutide QW and other GLP-1 receptor agonists (GLP-1 RAs) in a Japanese population, a network meta-analysis (NMA) was performed. The objective was to assess the relative efficacy and safety of semaglutide QW vs GLP-1 RAs in Japanese patients with type 2 diabetes (T2DM), with a specific focus on the comparison between semaglutide 0.5 mg QW and dulaglutide 0.75 mg QW.

METHODS

A systematic review (SR) and supplementary Japanese searches were conducted to identify trials of GLP-1 RAs in Japanese patients on diet and exercise, who have previously received 0-1 oral antidiabetic drugs (OADs). Data at 52-56 weeks were extracted for the following outcomes (feasible for analysis in an NMA): glycated hemoglobin (HbA_1c), fasting plasma glucose (FPG), weight, systolic blood pressure (SBP), and overall hypoglycemia. The data were synthesized using an NMA and a Bayesian framework.

RESULTS

Four trials, identified from the SR and Japanese-specific searches, were relevant for inclusion in the NMA. When compared to dulaglutide 0.75 mg QW, semaglutide 0.5 mg QW was shown to provide significant reductions in HbA_1c [- 0.61% (12.3 mmol/mol)], weight (- 1.45 kg), SBP (- 5.03 mmHg), and FPG (- 1.26 mmol/L). No significant differences in the proportion of patients achieving a HbA_1c level < 7% (53 mmol/mol) or the risk of overall hypoglycemia were observed between semaglutide 0.5 mg QW and dulaglutide 0.75 mg QW.

CONCLUSION

Overall, semaglutide 0.5 mg QW was associated with significant reductions from baseline in HbA_1c, weight, SBP, and FPG compared with dulaglutide 0.75 mg QW in Japanese patients with T2DM. These data may provide valuable evidence for clinical decision-making, cost-effectiveness analyses, and health technology appraisal (HTA) requirements.

FUNDING

Novo Nordisk Pharma Ltd.

A Systematic Literature Review and Network Meta-Analysis Comparing Once-Weekly Semaglutide with Other GLP-1 Receptor Agonists in Patients with Type 2 Diabetes Previously Receiving Basal Insulin

INTRODUCTION

Once-weekly semaglutide is a glucagon-like peptide-1 (GLP-1) analogue that is currently available as 1.0 mg and 0.5 mg dose for the treatment of type 2 diabetes (T2D). Currently, no head-to-head trial investigating once-weekly semaglutide as an add-on to basal insulin vs other GLP-1 receptor agonists (GLP-1 RAs) is available. The aim of this study was to conduct a network meta-analysis (NMA) to assess the efficacy and safety of once-weekly semaglutide vs other GLP-1 RAs in patients with T2D inadequately controlled on basal insulin.

METHODS

A systematic literature review was performed to identify all trials of GLP-1 RAs as an add-on to basal insulin in patients with T2D. Data at 24 ± 4 weeks were extracted for efficacy and safety outcomes (feasible for analysis in an NMA), including the change from baseline in glycated hemoglobin (HbA1c), body weight, and systolic blood pressure, and the incidence of nausea, vomiting, and diarrhea. Data were synthesized using a NMA and a Bayesian framework.

RESULTS

In total, eight studies were included across the base-case analyses. The results demonstrate that once-weekly semaglutide 1.0 mg was associated with significantly greater reductions in HbA1c (- 0.88% to - 1.39% vs comparators) and weight (- 1.49 to - 4.69 kg vs comparators) and similar odds of experiencing nausea, vomiting, or diarrhea vs all GLP-1 RA comparators. Once-weekly semaglutide 1.0 mg was also equally effective at reducing systolic blood pressure compared with liraglutide 1.8 mg. Once-weekly semaglutide 0.5 mg significantly reduced HbA1c vs the majority of other GLP-1 RAs, except liraglutide 1.8 mg QD. The odds of experiencing nausea were significantly lower with once-weekly semaglutide 0.5 mg compared with all GLP-1 RA comparators.

CONCLUSION

Once-weekly semaglutide 1.0 mg as an add-on to basal insulin is likely to be the most efficacious GLP-1 RA for reducing HbA1c and weight from baseline after 6 months of treatment. The efficacy of once-weekly semaglutide is not associated with a significant increase in the incidence of gastrointestinal side-effects vs other GLP-1 RAs.

FUNDING

Novo Nordisk.

Simulation in paediatric urology and surgery, part 2: An overview of simulation modalities and their applications

Surgical training has changed radically in the last few decades. The traditional Halstedian model of time-bound apprenticeship has been replaced with competency-based training. In our previous article, we presented an overview of learning theory relevant to clinical teaching; a summary for the busy paediatric surgeon and urologist. We introduced the concepts underpinning current changes in surgical education and training. In this next article, we give an overview of the various modalities of surgical simulation, the educational principles that underlie them, and potential applications in clinical practice. These modalities include; open surgical models and trainers, laparoscopic bench trainers, virtual reality trainers, simulated patients and role-play, hybrid simulation, scenario-based simulation, distributed simulation, virtual reality, and online simulation. Specific examples of technology that may be used for these modalities are included but this is not a comprehensive review of all available products.

A Systematic Review of Insulin Adherence Measures in Patients with Diabetes

BACKGROUND

Diabetes care is associated with a considerable burden to the health care system in the United States, and measuring the quality of health care is an important development goal of the Department of Health and Human Services and the Centers for Medicare & Medicaid Services. Diabetes is a priority disease within the National Quality Strategy and should therefore remain a focus in the measurement of health care quality. Despite the importance of measuring quality in diabetes care management, no quality measure is currently associated with adherence to insulin treatment, and measuring adherence to insulin is known to be complicated.

OBJECTIVES

To (a) identify methods to measure insulin adherence in patients with diabetes and (b) evaluate whether identified methods could be considered for testing as a quality measure.

METHODS

Systematic searches were conducted in the online electronic databases Embase, MEDLINE, and the Cochrane Library, supplemented with additional manual searches to identify publications on insulin adherence from the year 2000 onward. Identified citations were screened for relevance against predefined eligibility criteria, and methods to measure adherence to insulin were extracted from relevant studies into data extraction tables. Methods were critiqued on the feasibility for consideration as a quality measure.

RESULTS

Seventy-eight publications met the inclusion criteria and were reviewed. Included studies reported various indirect methods to measure adherence to insulin, using prescription claims or self-report questionnaires. Commonly reported methods included the (adjusted) medication possession ratio, proportion of days covered, persistence, daily average consumption, and the Morisky Medication Adherence Scale. All types of identified methods were associated with measuring challenges varying from accuracy of estimated adherence, complexity of data collection, absence of validated threshold for good adherence, and reliability of adherence outcomes.

CONCLUSIONS

Without additional research, none of the identified methods are appropriate for use as a quality measure for insulin adherence. We suggest patient involvement in future research and additional quality measure development.

DISCLOSURES

Novo Nordisk paid DRG Abacus to complete the systematic review and manuscript and was involved in the study design, interpretation of data, and decision to publish the findings of the systematic review. Kroes and Webb report personal fees from Novo Nordisk during the conduct of the study and personal fees from DRG Abacus, outside of the submitted work. Webb is employed by DRG Abacus, and Kroes was employed by DRG Abacus at the time of this study. Wisniewski is an employee of Novo Nordisk, which funded the systematic review reported in this article, and also owns stocks in Novo Nordisk. Stolpe has nothing to disclose. Study concept and design were contributed by Kroes, Webb, and Wisniewski, with assistance from Stolpe. Webb took the lead in data collection, along with Kroes, and data interpretation was performed by all the authors. The manuscript was written by Kroes, Webb, and Wisniewski, with assistance from Stolpe, and revised by Kroes, Stolpe, Wisniewski, and Webb.

The 3' addition of CCA to mitochondrial tRNASer(AGY) is specifically impaired in patients with mutations in the tRNA nucleotidyl transferase TRNT1

Addition of the trinucleotide cytosine/cytosine/adenine (CCA) to the 3' end of transfer RNAs (tRNAs) is essential for translation and is catalyzed by the enzyme TRNT1 (tRNA nucleotidyl transferase), which functions in both the cytoplasm and mitochondria. Exome sequencing revealed TRNT1 mutations in two unrelated subjects with different clinical features. The first presented with acute lactic acidosis at 3 weeks of age and developed severe developmental delay, hypotonia, microcephaly, seizures, progressive cortical atrophy, neurosensorial deafness, sideroblastic anemia and renal Fanconi syndrome, dying at 21 months. The second presented at 3.5 years with gait ataxia, dysarthria, gross motor regression, hypotonia, ptosis and ophthalmoplegia and had abnormal signals in brainstem and dentate nucleus. In subject 1, muscle biopsy showed combined oxidative phosphorylation (OXPHOS) defects, but there was no OXPHOS deficiency in fibroblasts from either subject, despite a 10-fold-reduction in TRNT1 protein levels in fibroblasts of the first subject. Furthermore, in normal controls, TRNT1 protein levels are 10-fold lower in muscle than in fibroblasts. High resolution northern blots of subject fibroblast RNA suggested incomplete CCA addition to the non-canonical mitochondrial tRNA(Ser(AGY)), but no obvious qualitative differences in other mitochondrial or cytoplasmic tRNAs. Complete knockdown of TRNT1 in patient fibroblasts rendered mitochondrial tRNA(Ser(AGY)) undetectable, and markedly reduced mitochondrial translation, except polypeptides lacking Ser(AGY) codons. These data suggest that the clinical phenotypes associated with TRNT1 mutations are largely due to impaired mitochondrial translation, resulting from defective CCA addition to mitochondrial tRNA(Ser(AGY)), and that the severity of this biochemical phenotype determines the severity and tissue distribution of clinical features.

Detection of high-energy gamma-ray emission from the globular cluster 47 Tucanae with Fermi

We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17sigma from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that they contain. The spectral shape of 47 Tucanae is consistent with gamma-ray emission from a population of millisecond pulsars. The observed gamma-ray luminosity implies an upper limit of 60 millisecond pulsars present in 47 Tucanae.

ApTrkl, a Trk-like Receptor, Mediates Serotonin- Dependent ERK Activation and Long-Term Facilitation in Aplysia Sensory Neurons

The Trk family of receptor tyrosine kinases plays a role in synaptic plasticity and in behavioral memory in mammals. Here, we report the discovery of a Trk-like receptor, ApTrkl, in Aplysia. We show that it is expressed in the sensory neurons, the locus for synaptic facilitation, which is a cellular model for memory formation. Serotonin, the facilitatory neurotransmitter, activates ApTrkl, which, in turn, leads to activation of ERK. Finally, inhibiting the activation of ApTrkl with the Trk inhibitor K252a or using dsRNA to inhibit ApTrkl blocks the serotonin-mediated activation of ERK in the cell body, as well as the cell-wide long-term facilitation induced by 5-HT application to the cell body. Thus, transactivation of the receptor tyrosine kinase ApTrkl by serotonin is an essential step in the biochemical events leading to long-term facilitation in Aplysia.

Covariation in regulation of affinity for branchial zinc and calcium uptake in freshwater rainbow trout

The possible coupling between regulation of the affinities for branchial Zn and Ca influx was investigated in juvenile rainbow trout Oncorhynchus mykiss acclimated to relatively hard fresh water ([Ca]=1.0 mmol l-1). The Km for branchial Ca influx was manipulated experimentally by exposing the fish to 2.3 micromol l-1 waterborne Zn for a total of 28 days. This procedure resulted in rapidly increased Km values for both Ca and Zn influx, an effect that remained through the experimental period. There was a significant linear correlation (r=0.88, P&lt;0.02) between Km values for Ca and Zn measured at the same time points. Zn exposure caused progressively increasing maximum rate of transport, Jmax, values for Zn relative to the control value, but there was little, if any, effect on Jmax for Ca. These results support the idea of a shared transport site for Zn and Ca at the apical membrane of the gill epithelium and suggest that there is a certain degree of coregulation of branchial Zn and Ca uptake in rainbow trout. Removal of Ca from the water resulted in a large (six- to 24-fold) increase in affinity (decreased Km) for Zn influx and a modest (1.1- to 1.8-fold) increase in Jmax for Zn. Thus, Ca is a competitive inhibitor of Zn influx. In water lacking Ca, the Km for Zn in Zn-acclimated fish was no different from that of the control fish, suggesting that the Ca2+/Zn2+ transporter was regulated to improve Ca uptake.

Developing a plan for primary health care facilities in Soweto, South Africa. Part I: Guiding principles and methods

The new political era in South Africa offers unique opportunities for the development of more equitable health care policies. However, resource constraints are likely to remain in the foreseeable future, and efficiency therefore remains an important concern. This article describes the guiding principles and methods used to develop a coherent and objective plan for comprehensive primary health care facilities in Soweto. The article begins with an overview of the context within which the research was undertaken. Problems associated with planning in transition are highlighted, and a participatory research approach is recommended as a solution to these problems. The article goes on to describe how the research methods were developed and applied in line with the principles of participatory research. The methods were essentially rapid appraisal techniques which included group discussions, detailed checklists, observation, record reviews and the adaptation of international and local guidelines for service planning. It is suggested that these methods could be applied to other urban areas in South Africa and elsewhere, and that they are particularly appropriate in periods of transition when careful facilitation of dialogue between stakeholders is required in tandem with the generation of rapid results for policy-makers.

Developing a plan for primary health care facilities in Soweto, South Africa. Part II: Applying locational criteria

This article is the second of a two-part series describing the development of a ten-year plan for primary health care facility development in Soweto. The first article concentrated on the political problems and general methodological approach of the project. This second article describes how the technical problem of planning in the context of scanty information was overcome. The reasoning behind the various assumptions and criteria which were used to assist the planning of the location of facilities is explained, as well as the process by which they were applied. The merits and limitations of this planning approach are discussed, and it is suggested that the approach may be useful to other facility planners, particularly in the developing world.