Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Surface modification of Polyether-ether-ketone for enhanced cell response: a chemical etching approach

Polyether-ether-ketone (PEEK) is increasingly becoming popular in medicine because of its excellent mechanical strength, dimensional stability, and chemical resistance properties. However, PEEK being bioinert, has weak bone osseointegration properties, limiting its clinical applications. In this study, a porous PEEK structure was developed using a chemical etching method with 98 wt% sulfuric acids and three post-treatments were performed to improve bone cell adhesion and proliferation. Four groups of PEEK samples were prepared for the study: Control (untreated; Group 1); Etched with sulfuric acid and washed with distilled water (Group 2); Etched with sulfuric acid and washed with acetone and distilled water (Group 3); and Etched with sulfuric acid and washed with 4 wt% sodium hydroxide and distilled water (Group 4). Surface characterization of the different groups was evaluated for surface topology, porosity, roughness, and wettability using various techniques, including scanning electron microscopy, profilometer, and goniometer. Further chemical characterization was done using Energy-dispersive X-ray spectroscopy to analyze the elements on the surface of each group. Bone cell studies were conducted using cell toxicity and alkaline phosphatase activity (ALP) assays. The SEM analysis of the different groups revealed porous structures in the treatment groups, while the control group showed a flat topology. There was no statistically significant difference between the pore size within the treated groups. This was further confirmed by the roughness values measured with the profilometer. We found a statistically significant increase in the roughness from 7.22 × 10-3 μm for the control group to the roughness range of 0.1 µm for the treated groups (Groups 2-4). EDX analysis revealed the presence of a 0.1% weight concentration of sodium on the surface of Group 4, while sulfur weight percentage concentration was 1.1%, 0.1%, and 1.4% in groups 2, 3, and 4, respectively, indicating different surface chemistry on the surface due to different post-treatments. Cell toxicity decreased, and ALP activity increased in groups 3 and 4 over 7 days compared with the control group. It is demonstrated that the surface modification of PEEK using a chemical etching method with post-processing with either acetone or sodium hydroxide provides a nano-porous structure with improved properties, leading to enhanced osteoblastic cell differentiation and osteogenic potential.

The diabetes community exercise programme plus usual care versus usual care in patients with type 2 diabetes: A randomised, two-arm, parallel, open-label trial

BACKGROUND

Exercise is important in type 2 diabetes (T2D) management. Focussing on Māori and Pacific people and those from deprived circumstances, the Diabetes Community Exercise Programme (DCEP) was developed to engage people with T2D in exercise. We report the evaluation of whether being offered DCEP (plus usual care) was more effective than usual care in improving glycaemic control at 1-year.

METHODS

A randomised, two-arm, parallel, open-label trial with blinding of outcome assessor and data analyst. Adults (age ≥35 years) with T2D recruited from two New Zealand (NZ) communities were randomised, using opaque sealed envelopes and stratified by centre with random block lengths, to DCEP or usual care. DCEP comprises twice-weekly, two-hour sessions of exercise and education over 12-weeks, followed by a twice-weekly maintenance exercise class. The primary outcome was between-group differences in mean changes of glycated haemoglobin (HbA1c) from baseline to 1-year follow-up with intention-to treat analysis. This trial is registered with the Australian NZ Clinical Trials Registry (ANZCTR): ACTRN12617001624370p and is closed to new participants.

FINDINGS

From 2018 - 2019, of 294 people screened, 165 (mean age 63·8, SD16·2 years, 56% female, 78·5% European, 14% Māori, 6% Pacific, 27% most deprived) were baseline evaluated, randomised, and analysed at study end (DCEP = 83, control = 82). Multimorbidity (≥2) and polypharmacy (>5 medications) were high (82%, 69%). We found no statistically significant between-groups differences in HbA1c (mmol/mol) change at 15 months (mean 3% higher in DCEP, 95% CI 2% lower to 8% higher, p = 0·23). Twelve-week intervention adherence was good (41% attended >80% available sessions). No adverse events were reported.

INTERPRETATION

DCEP was not effective in improving glycaemic control, possibly due to insufficient exercise intensity. Our attendance demonstrated DCEP's cultural accessibility. DCEP might be good to engage in exercise marginalised people with high Hb1Ac levels, multimorbidity, and high polypharmacy.

FUNDING

Health Research Council of New Zealand.

Enumeration of Total Aerobic Microorganisms in Foods by SimPlate® Total Plate Count–Color Indicator Methods and Conventional Culture Methods: Collaborative Study

The relative efficacy of the SimPlate® Total Plate Count–Color Indicator (TPC–CI) method (SimPlate 35°C) was compared with the AOAC Official Method 966.23 (AOAC 35°C) for enumeration of total aerobic microorganisms in foods. The SimPlate TPC–CI method, incubated at 30°C (SimPlate 30°C), was also compared with the International Organization for Standardization (ISO) 4833 method (ISO 30°C). Six food types were analyzed: ground black pepper, flour, nut meats, frozen hamburger patties, frozen fruits, and fresh vegetables. All foods tested were naturally contaminated. Nineteen laboratories throughout North America and Europe participated in the study. Three method comparisons were conducted. In general, there was &lt;0.3 mean log count difference in recovery among the SimPlate methods and their corresponding reference methods. Mean log counts between the 2 reference methods were also very similar. Repeatability (sr) and reproducibility (sR) standard deviations were similar among the 3 method comparisons. The SimPlate method (35°C) and the AOAC method were comparable for enumerating total aerobic microorganisms in foods. Similarly, the SimPlate method (30°C) was comparable to the ISO method when samples were prepared and incubated according to the ISO method.

Visual Immunoprecipitate Assay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.09): Collaborative Study

AOAC Official Method 996.09, Visual Immunoprecipitate Assay (VIP®) for Escherichia coli O157:H7, was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by VIP assay and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment procedure and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 15 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level, where predominantly positive results were expect d, and a low level where fractional recovery was anticipated. Collaborators tested 396 test portions and controls by both methods, for a total of 792 test portions. Of the 396 paired test portions, 75 were positive and 230 were negative by both the VIP and culture methods. Eleven test portions were presumptively positive by VIP and could not be confirmed culturally; 32 were negative by VIP, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the VIP method. There was no statistical difference between results obtained with the VIP for EHEC 8 h method and the culture method except for cooked beef, where the VIP had significantly higher recovery for one inoculation level.

Assurance® Enzyme Immunoassay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.10): Collaborative Study

AOAC Official Method 996.10, Assurance® Enzyme Immunoassay (EIA) for Escherichia coli O157:H7 (EHEC), was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by EIA and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment conditions and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 14 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. Collaborators tested 378 test portions and controls by both the 8 h EIA and the USDA/FSIS enrichment methods, for a total of 756 test portions. Of the 378 paired test portions, 75 were positive and 212 were negative by both methods. Thirteen test portions were presumptively positive by EIA and could not be confirmed culturally; 30 were negative by EIA, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the EIA method. There was no statistical difference between results obtained with the Assurance EIA for EHEC 8 h method and the culture method for raw ground beef. The Assurance EIA had a significantly higher recovery for cooked beef.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

The confidence of undergraduate dental students when carrying out prosthodontic treatment and their perception of the quality of prosthodontic education

INTRODUCTION

Despite the falling number of edentulous patients within the UK, there is still a large demand for the provision of removable prostheses. On qualification, dentists should have the knowledge and skills to provide these prostheses, but previous studies have shown that final-year dental undergraduate confidence in treating denture patients is lacking.

AIM

To explore undergraduate dental student confidence whilst carrying out prosthodontic treatment, and to explore their perceptions of the quality of their prosthodontic education.

METHOD

An anonymous questionnaire was distributed to all (n=203) dental undergraduates in Years 3 to 5 at the University of Bristol. The questionnaire utilised a range of data collection methods including confidence interval ranked responses and qualitative measures. The data were analysed using SPSS.

RESULTS

The response rate was 51%. Undergraduate perception of confidence increased throughout the years of study (P<.001). There was also an increase in the number of partial and complete denture cases treated as students progressed through the course (P<.001). Overall, students were satisfied with their prosthodontic teaching, although students thought that too much time was allocated to laboratory teaching, and that increasing their clinical experience would be most beneficial in increasing their confidence levels.

CONCLUSION

Student confidence in carrying out prosthetic treatment increased as students progressed through the course, and confidence levels would be increased further with increased clinical experience.

Observation of edge instability limiting the pedestal growth in tokamak plasmas

With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand the physical mechanism dictating the pedestal characteristics and to validate and improve pedestal predictive models. This Letter reports direct evidence of density and magnetic fluctuations showing the stiff onset of an edge instability leading to the saturation of the pedestal on the Alcator C-Mod tokamak. Edge stability analyses indicate that the pedestal is unstable to both ballooning mode and kinetic ballooning mode in agreement with observations.

Service user involvement in pre-registration mental health nurse education classroom settings: a review of the literature

Service user involvement in pre-registration nurse education is now a requirement, yet little is known about how students engage with users in the classroom, how such initiatives are being evaluated, how service users are prepared themselves to teach students, or the potential influence on clinical practice. The aim of this literature review was to bring together published articles on service user involvement in classroom settings in pre-registration mental health nurse education programmes, including their evaluations. A comprehensive review of the literature was carried out via computer search engines and the Internet, as well as a hand search of pertinent journals and references. This produced eight papers that fitted the inclusion criteria, comprising four empirical studies and four review articles, which were then reviewed using a seven-item checklist. The articles revealed a range of teaching and learning strategies had been employed, ranging from exposure to users' personal stories, to students being required to demonstrate awareness of user perspectives in case study presentations, with others involving eLearning and assessment skills initiatives. This review concludes that further longitudinal research is needed to establish the influence of user involvement in the classroom over time.

Delivering a basic mental health training programme: views and experiences of Mental Health First Aid instructors in Wales

Originating in Australia, 'Mental Health First Aid' (MHFA) is a way of providing support to someone who is experiencing a mental health problem before professional help is obtained. Positive evaluations have shown that it both increases confidence while decreasing stigmatizing attitudes. However, the evidence base surrounding the delivery of basic mental health programmes remains underdeveloped. This descriptive qualitative study explored the views and experiences of 14 MHFA instructors from across Wales through semi-structured interviews, as a means to identify the experience of course delivery from their perspective. Data were collected between January and April 2009. The study found individuals benefited from being an MHFA instructor through increased confidence and self-development. However, instructors encountered logistical difficulties in course delivery and noted that as attendees related to the course material, they wished to discuss their own mental health problems during the course. This created considerable challenges for instructors, who noted both positive and negative impacts on themselves, and on their expectations of the role of becoming MHFA instructors. In conclusion, basic mental health training courses must build a clear infrastructure, ongoing quality assurance processes and reliable support structures to train, support and monitor those delivering them.

Experiences of instructors delivering the Mental Health First Aid training programme: a descriptive qualitative study

Mental health literacy among the public is often poor, and although people frequently encounter others experiencing mental distress in their workplace, families and communities, they may be ill-equipped to provide appropriate support. 'Mental Health First Aid' (MHFA), a 12-h mental health promotion programme seeks to address this, training people in the knowledge and skills needed to engage with someone experiencing mental health problems. Research relating to the MHFA programme has centred on course attendees, with a paucity of research surrounding the delivery of basic mental health training programmes. Understanding experiences of instructors delivering such programmes is key to the success of future delivery. This study sought to identify the views and experiences of instructors delivering the MHFA programme in Wales. Fourteen MHFA instructors participated in semi-structured audio-recorded interviews, with the transcripts analysed to identify key themes. This paper explores two of the identified themes namely prerequisite skills and support required by instructors. The study highlighted that because of the ensuing emotional labour experienced by instructors, universal mental health training programmes must put in place a clear infrastructure to train, support and monitor those delivering them, for programme roll-out to be effective.

[Recording of synaptic currents with extracellular electrodes]

Recordings made by multielectrodes distributed in depth of the cortex are used for the system level study of the brain. The distribution of the extracellular potential obtained contains information about the input signals of pyramidal neurons in the cortex, the synaptic currents. A method of the estimation of the synaptic current distribution is described, which is based on the solution of the reverse problem for a system of homogeneously distributed parallel cylinders as a model of dendrites of the pyramidal neurons. The estimations are compared to the data both known from literature and obtained by an independent model.

Impact of telomerase status on canine osteosarcoma patients

BACKGROUND

We demonstrated previously that canine osteosarcoma (OSA) cell lines and samples from clinical patients are predominantly telomerase positive. In contrast, the majority of OSA samples from human patients appear to be telomerase negative, maintaining telomere length by an alternative lengthening of telomeres (ALT) mechanism. The purpose of the current study was to examine the telomerase status of a large number of OSA samples from dogs and determine if telomerase status can serve as a prognostic factor.

HYPOTHESIS

The majority of clinical canine OSA appendicular lesions will be telomerase positive, and telomerase positivity will negatively impact disease outcome.

ANIMALS

Sixty-seven dogs with appendicular OSA presenting to the Colorado State University Animal Cancer Center for treatment.

METHODS

The Telomeric Repeat Amplification Protocol was performed on tissue samples from primary canine appendicular OSA to determine the presence of telomerase activity. Telomere restriction fragment (TRF) analysis was utilized to determine telomere length and detect ALT. Outcome data were obtained in a retrospective manner and correlated with telomerase status.

RESULTS

Seventy-three percent of canine OSA samples were telomerase positive. Telomerase status did not have an impact on disease-free interval or survival time. Nine of 10 telomerase-negative samples examined were consistent with an ALT phenotype, based on TRF analysis.

CONCLUSIONS AND CLINICAL IMPORTANCE

These results are consistent with the hypothesis that the majority of canine OSA are telomerase positive, suggesting that telomerase may be a valuable target for canine OSA therapy. Additionally, telomerase status does not appear to be a prognostic factor in canine OSA.

Proximal anterior cruciate ligament avulsion fracture in a skeletally immature athlete: a case report and method of physeal sparing repair

Traumatic rupture of the anterior cruciate ligament (ACL) in adulthood is relatively common and surgical reconstruction is frequently required to allow return to high-level activities. There is growing evidence to suggest that ACL rupture in children is more common than previously thought and a poor outcome is associated with conservative management. The site of rupture in childhood is predominantly tibial avulsion, but mid-substance tears have also been reported. We report a case of a proximal ACL avulsion in an 11-year-old athlete and discuss a method of extra-physeal repair. There are very few previous reports of proximal avulsion fractures in skeletally immature patients.

In situ characterization and mapping of iron compounds in Alzheimer's disease tissue

There is a well-established link between iron overload in the brain and pathology associated with neurodegeneration in a variety of disorders such as Alzheimer's (AD), Parkinson's (PD) and Huntington's (HD) diseases [1]. This association was first discovered in AD by Goodman in 1953 [2], where, in addition to abnormally high concentrations of iron in autopsy brain tissue, iron has also been shown to accumulate at sites of brain pathology such as senile plaques [3]. However, since this discovery, progress in understanding the origin, role and nature of iron compounds associated with neurodegeneration has been slow. Here we report, for the first time, the location and characterisation of iron compounds in human AD brain tissue sections. Iron fluorescence was mapped over a frontal-lobe tissue section from an Alzheimer's patient, and anomalous iron concentrations were identified using synchrotron X-ray absorption techniques at 5 mum spatial resolution. Concentrations of ferritin and magnetite, a magnetic iron oxide potentially indicating disrupted brain-iron metabolism, were evident. These results demonstrate a practical means of correlating iron compounds and disease pathology in-situ and have clear implications for disease pathogenesis and potential therapies.

Purification of the RelB and RelE proteins of Escherichia coli: RelE binds to RelB and to ribosomes

The direct interaction of the Escherichia coli cytotoxin RelE with its specific antidote, RelB, was demonstrated in two ways: (i) copurification of the two proteins and (ii) a positive yeast two-hybrid assay involving the relB and relE genes. In addition, the purified RelE protein exhibited ribosome-binding activity in an in vitro assay, supporting previous observations suggesting that it is an inhibitor of translation.

Dementia, quantitative neuroimaging, and apolipoprotein E genotype

BACKGROUND AND PURPOSE

Quantitative MR imaging differences in an elderly population of subjects with various clinical disorders (including dementia, particularly Alzheimer's disease and vascular dementia) and disorders of mild cognitive impairment were examined. Potential quantitative MR differences were assessed by presence or absence of the apolipoprotein E (APOE) epsilon4 allele and by level of cognitive deficit.

METHODS

One hundred eighty subjects with a diagnosis of dementia or other clinical disorders were identified from an eligible population of 5,677 elderly individuals. Age, duration of disease, and head size (where appropriate) were considered as covariates. APOE genotype was determined by polymerase chain reaction using buccal material. Axial and coronal intermediate- and T2-weighted MR images were quantified using a multispectral segmentation algorithm. Cognitive status was assessed by means of a modified Mini-Mental Status Examination.

RESULTS

All types of dementing illness showed significant volume reductions in the majority of structures examined, particularly in the total brain, hippocampus, and white and gray matter, and increased CSF and ventricular volumes. Subjects with mild cognitive impairment showed fewer atrophic changes but were still distinguishable from the 24 control subjects. Presence of an epsilon4 allele was associated with smaller hippocampal volume in subjects with Alzheimer's disease and vascular dementia within just 1 year of disease onset. For other analyses, atrophy related to the presence of the epsilon4 allele disappeared after controlling for age and length of disease.

CONCLUSION

The effects of the epsilon4 allele on brain morphology may be subtly expressed early in the development of dementia, but do not specifically affect cerebral atrophy thereafter. Cognitive impairment is associated with atrophy irrespective of diagnosis and presence of epsilon4.

A cluster of leptospirosis among abattoir workers

In early December 1998, the Northern Rivers Public Health Unit (north-eastern New South Wales) was alerted to a possible cluster of leptospirosis cases by the supervising scientist of the Western Pacific Region World Health Organization/Food and Agricultural Organization Collaborating Centre for Reference and Research on Leptospirosis. Investigation revealed a cluster of eight leptospirosis cases diagnosed during October and November 1998. All were employees of a local meat works. Leptospira serovars isolated included pomona and hardjo. Symptoms included headache, fever, muscle pain, sore eyes, abdominal pain, vomiting, jaundice, and rash. Five of the eight cases were hospitalised. The infection could not be traced to any particular source. Unfortunately, records of stock killed during the exposure periods were not available. All cases reported exposure to large volumes of animal urine during the course of their work. Protective clothing provided included an apron, gloves, and rubber boots. All of the patients said they wore rubber boots and seven of the eight wore the apron provided. Only two patients reported wearing gloves, the remainder thought these were too difficult to work in.

Metabolic responses to fructose-1,6-diphosphate in healthy subjects

Fructose-1,6-diphosphate (FDP) is an important naturally occurring intracellular metabolite with a direct regulatory role in many metabolic pathways. The most important and widely studied of the FDP effects has been its regulation of glycolysis, particularly the enzyme that synthesizes FDP--phosphofructokinase (PFK). Since it was observed experimentally that FDP does indeed modulate carbohydrate metabolism, we investigated whether FDP would similarly enhance carbohydrate utilization in man. The study used indirect calorimetry and was open to healthy adults (N = 45) of either sex and above legal age. After a steady metabolic state was obtained, 5 g of FDP (10%) was infused into a brachial vein. In 10 subjects, glucose (5 g) or FDP (5 g) was sequentially infused. The rapid intravenous infusion of FDP produced a slight but significant decrease in heart and respiration rates (P < .05). A significant increase in the serum concentration of inorganic phosphate (P < .0001) and the intraerythrocytic concentration of adenosine triphosphate (ATP) (P < .01) was also observed. The FDP infusion produced a decrease in plasma cholesterol and triglycerides (P < .001 and P < .01, respectively). The indirect calorimetric data indicate that the infusion produced a highly significant increase in the respiratory quotient ([RQ] P < .0001) and the energy derived from carbohydrates (P < .0001) and a significant decrease in the energy derived from lipids (P < .0001). Glucose infusion did not cause changes in any of the parameters. These data indicate that carbohydrate metabolism is stimulated by FDP.

Carotid artery stenting in patients with high neurologic risks

Forty-four patient with high neurologic risks (Mayo class IV) successfully underwent carotid artery stenting with combined major stroke and death rates of 4.5%. Late follow-up at a mean of 23 +/- 1.8 months showed 1 non-neurologic death, but no neurologic events or repeat stenting procedures.

Choroidal neovascularization secondary to Candida albicans chorioretinitis

PURPOSE

To study the clinical histories and courses of six patients with choroidal neovascularization secondary to endogenous Candida albicans chorioretinitis.

METHODS

The medical records, fundus photographs, and fluorescein angiograms of six patients who developed C. albicans chorioretinitis secondary to candidemia and who subsequently developed choroidal neovascularization in one or both eyes were reviewed.

RESULTS

The six patients ranged in age from 18 to 79 years. Four were women and two men; all but one showed evidence of bilateral chorioretinal scarring secondary to C. albicans chorioretinitis. All patients had been treated successfully with systemic antifungal therapy (amphotericin B). Two weeks to two years after the chorioretinitis, choroidal neovascularization developed in one eye (four cases) or both eyes (two cases). The neovascularization on initial examination was subfoveal in four eyes, extrafoveal in three eyes, and juxtafoveal in one eye. Laser photocoagulation was used in four of the eight involved eyes. In these cases, the active choroidal neovascularization was brought under control. In one eye, the patient had submacular surgery for excision of the choroidal neovascular membrane. Final visual acuities ranged from 20/20 to 20/200 in treated eyes and from 20/50 to 20/400 in untreated eyes.

CONCLUSION

Choroidal neovascularization is a potential cause of late visual loss in patients who have had C. albicans sepsis and endogenous C. albicans chorioretinitis. Eyes that have chorioretinal scarring from C. albicans chorioretinitis should be watched for the development of choroidal neovascularization. Laser photocoagulation or perhaps surgical excision of the neovascular complex may be of benefit in selected cases.

Effect of cocaine on left ventricular function. Relation to increased wall stress and persistence after treatment

BACKGROUND

To determine whether alterations in left ventricular (LV) function after a cocaine infusion are due to reduced myocardial contractility or changes in loading conditions, we examined LV function in 30 morphine-sedated, closed-chest dogs. We also wanted to determine the time course of the effects of cocaine on LV function after the infusion was stopped.

METHODS AND RESULTS

Two-dimensional echocardiography and hemodynamics provided LV fractional shortening and end-systolic wall stress data. Radionuclide ventriculography was also performed. Four groups of dogs received saline or cocaine infusions of 10, 30, or 100 micrograms.kg-1.min-1. Cocaine was infused for 90 minutes with ECG and arterial pressure monitoring. Animals were monitored for an additional 120 minutes after the infusion ended. Arterial pressure rose over the course of the experiment in all four groups, but saline and cocaine 10 micrograms.kg-1.min-1 did not significantly change ejection fraction. Cocaine 30 and 100 micrograms.kg-1.min-1 acutely increased arterial pressure and heart rate but decreased ejection fraction from 0.64 +/- 0.06 to 0.45 +/- 0.08 and from 0.65 +/- 0.10 to 0.46 +/- 0.11, respectively. Additionally, cocaine 100 micrograms.kg-1.min-1 decreased fractional shortening from 36 +/- 9% to 23 +/- 12%. However, cocaine 30 and 100 micrograms.kg-1.min-1 also increased wall stress from 42 +/- 15 to 65 +/- 11 g/cm2 and from 37 +/- 15 to 90 +/- 33 g/cm2, respectively. These results were analyzed by use of the relation between wall stress and fractional shortening as an index of contractility. Fractional shortening after cocaine infusion was displaced downward as a result of increased wall stress rather than changes in contractility. In addition, alteration of afterload with phenylephrine (6 micrograms/kg) and sodium nitroprusside (10 micrograms/kg) before and during infusion of cocaine 100 micrograms.kg-1.min-1 showed similar regression lines for wall stress to fractional shortening.

CONCLUSIONS

Ejection-phase indexes of LV function were reduced by cocaine in this model of conscious, sedated dogs, but effects were attributable to increased wall stress rather than to reduced myocardial contractility. These effects persisted for at least 2 hours after the infusion was stopped.

The major electrolytes: sodium, potassium, and chloride

Electrolytes are substances that dissociate in solution and have the ability to conduct an electrical current. These substances are located in the extracellular and intracellular fluid. Within the extracellular fluid, the major cation is sodium and the major anion is chloride. The major cation in the intracellular fluid is potassium. These electrolytes play an important role in maintaining homeostasis. In this article, the etiology, signs, symptoms, and treatments for imbalances of these three electrolytes are reviewed.