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.

A23 ESTIMATING INDIRECT AND OUT-OF-POCKET COSTS IN PEDIATRIC INFLAMMATORY BOWEL DISEASE: A NATION-WIDE CROSS-SECTIONAL ANALYSIS

Background

Identifying disease-related costs is a crucial step to plan for proper allocation of resources and future healthcare services for persons with inflammatory bowel disease (IBD). Data on pediatric inflammatory bowel disease-associated costs are limited.

Aims

We aimed to estimate indirect and out of pocket (OOP) pediatric IBD-associated costs in Canada.

Methods

In a nation-wide cross-sectional analysis, caregivers of children and young adults (<17 years) with IBD were invited to complete a questionnaire on lost work hours and OOP costs related to IBD in the 4 weeks prior to the survey. Participants were re-invited to periodically answer the same questionnaire every 3–9 months for 2 years. Lost productivity was calculated using the Human Capital method. Costs were reported in 2018 inflation-adjusted Canadian dollars. Predictors of high cost users (top 25%) were examined using negative binomial regression.

Results

Consecutive 243 (82 incident cases) of 262 (92.7%) approached participants completed the first survey with a total of 450 surveys longitudinally completed over 2 years. The annual median indirect costs per patient were $5,951 (IQR $1,812- $12,278), with $5,776 (IQR $1,465-$11,733) for Crohn’s disease (CD) and $6,084 (IQR $2,470-$13,371) for ulcerative colitis (UC) (p=0.77). The annual median per patient OOP costs were $2,925 (IQR $978- $8,125) with $3,021 (IQR $978- $8,125) for CD and $2,600 (IQR $975- $8,125) for UC (p=0.55). Older age (10-17y) at diagnosis (p=0.04) and parents in part-time employment (p=0.01) were predictors of higher indirect costs, while female sex (p<0.001), parents with a lower education level (p<0.001) and lower annual family income (p<0.01) were associated with higher OOP costs.

Conclusions

Indirect and OOP IBD-associated costs are substantial and more likely to affect families with unstable employment and lower annual income. Examining different strategies and interventions to reduce these costs such as virtual platforms, telephone and outreach clinics especially in poor communities and families with low annual income is warranted.

Funding Agencies

CIHRThe Children’s Hospital Research Institute of Manitoba

Association between common cardiovascular risk factors and clinical phenotype in patients with hypertrophic cardiomyopathy from the European Society of Cardiology (ESC) EurObservational Research Programme (EORP) Cardiomyopathy/Myocarditis registry

AIMS

The interaction between common cardiovascular risk factors (CVRF) and hypertrophic cardiomyopathy (HCM) is poorly studied. We sought to explore the relation between CVRF and the clinical characteristics of patients with HCM enrolled in the EURObservational Research Programme (EORP) Cardiomyopathy registry.

METHODS AND RESULTS

1739 patients with HCM were studied. The relation between hypertension (HT), diabetes (DM), body mass index (BMI), and clinical traits was analysed. Analyses were stratified according to the presence or absence of a pathogenic variant in a sarcomere gene. The prevalence of HT, DM, and obesity (Ob) was 37, 10, and 21%, respectively. HT, DM, and Ob were associated with older age (P<0.001), less family history of HCM (HT and DM P<0.001), higher New York Heart Association (NYHA) class (P<0.001), atrial fibrillation (HT and DM P<0.001; Ob p = 0.03) and LV (left ventricular) diastolic dysfunction (HT and Ob P<0.001; DM P = 0.003). Stroke was more frequent in HT (P<0.001) and mutation-positive patients with DM (P = 0.02). HT and Ob were associated with higher provocable LV outflow tract gradients (HT P<0.001, Ob P = 0.036). LV hypertrophy was more severe in Ob (P = 0.018). HT and Ob were independently associated with NYHA class (OR 1.419, P = 0.017 and OR 1.584, P = 0.004, respectively). Other associations, including a higher proportion of females in HT and of systolic dysfunction in HT and Ob, were observed only in mutation-positive patients.

CONCLUSION

Common CVRF are associated with a more severe HCM phenotype, suggesting a proactive management of CVRF should be promoted. An interaction between genotype and CVRF was observed for some traits.

Long-term outcomes of 265,737 patients hospitalised with atrial fibrillation and atrial flutter from 2008 to 2015

Background

Atrial fibrillation/atrial flutter (AF/AFL) hospitalisations are common, however, little is known about the long-term outcomes of these episodes.

Objective

To examine the incidence of mortality, all-cause and cause-specific re-hospitalisations at up to 8 years after a hospitalisation for AF/AFL.

Methods

Unique patients hospitalised with a primary diagnosis of AF/AFL from 2008–2015 were identified using nation-wide hospitalisation data from Australia and New Zealand. All-cause mortality was the primary outcome. Secondary endpoints included all-cause and cause-specific re-hospitalisations. Results were reported as incident rate per 100 patient-years.

Results

We included 265,737 patients (mean age 69.9±13.9y, female 45.2%, elective 28.7%). The median length of stay was 1 day (Interquartile range [IQR] 0–4 days) and the median CHA2DS2-VASc score was 2 (IQR 1–2). During the index hospitalisation, 9,837 (3.7%) patients underwent catheter or surgical ablation and 52,634 (19.8%) underwent cardioversion. During the median follow-up time of 3.4 years (range 0–8.0 years), 53,669 patients died (incident rate of 5.7/100 patient-years) with a survival probability gradually decreasing from 92.8% (95% CI 92.7–92.9%) at 1-year to 65.4% (95% CI 64.9–65.8%) at 8-years post-discharge (Table 1 and Figure 1). All-cause re-hospitalisations occurred in 210,118 patients (incident rate of 22.2/100 patient-years) with a rehospitalisation-free survival probability of 7.1% (95% CI 6.9—7.3%) at the end of follow-up. Unplanned re-hospitalisations occurred more frequently than planned episodes (incident rate of 17.2 vs. 16.6/100 patient-years respectively). AF/AFL accounted for 25.1% of all-cause re-hospitalisations (incident rate of 8.9/100 patient-years) and the probability of freedom from re-hospitalisations for AF/AFL was 55.4% (95% CI 55.0–55.8%) at 8-years. Incident rates of re-hospitalisations for catheter ablation (1.5/100 patient-years), stroke (1.6/100 patient-years), heart failure (2.7/100 patient-years), and acute myocardial infarction (1.0/100 patient-years) were low. In subgroup analyses, worse survival was observed in female patients, older age groups, patients with comorbid heart failure, hypertension, diabetes, and those who did not undergo ablation during the index hospitalisation.

Conclusion

Nearly two-thirds of patients were surviving by 8-years following an AF/AFL hospitalisation with a low rate of re-hospitalisations for stroke, heart failure, and myocardial infarction. However, re-hospitalisations for recurrent atrial arrhythmia were common. Efforts to reduce re-hospitalisations, especially unplanned encounters, are required to improve patient outcomes.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Heart Foundation of Australia

A228 EVOLUTION OF MRE FINDINGS IN PAEDIATRIC PATIENTS WITH SMALL BOWEL CROHN’S DISEASE ON MAINTENANCE METHOTREXATE

Background

Observational data in children and RCT data in adults indicate that methotrexate (MTX) is associated with induction and maintenance of clinical remission in luminal Crohn’s disease, but efficacy in achieving intestinal healing has not been examined.

Aims

To examine the evolution of MRE signs of inflammation in children treated with MTX.

Methods

In this retrospective cohort study, we reviewed paediatric CD patients on maintenance MTX monotherapy for &gt;4 months who underwent serial MREs between July 2010 and October 2015. MREs were reviewed by a radiologist blind to clinical data. Overall inflammatory activity on each MRE was scored as minimal, mild, moderate or severe, informed by the presence of bowel wall thickness, wall enhancement, T2 hyperintensity, comb sign, mesenteric edema, penetrating disease, stricturing, diffusion restriction and motility. The radiologist’s global assessment of change from MRE 1 to MRE 2 was scored as improved, unchanged or worsened. Clinical findings, disease activity (assessed by weighted paediatric CD activity index [wPCDAI]) and surgical history were also extracted from medical records by a clinician blind to MRE results.

Results

Thirty-five patients were included (median age at diagnosis 12 [IQR 11–14] years; 77% male; 60% inflammatory (B1), 17% stricturing (B2), 23% penetrating (B3) disease). Between baseline and follow-up MRE, wPCDAI (median 15 [IQR 7–43] decreased to 8 [IQR 0–18]; p=0.006) and CRP (median 9 [IQR 2–36] decreased to 5 [IQR 5–9]; p=0.013) and 74% (N=26) were in clinical remission (wPCDAI &lt; 12.5) at MRE 2. MRE features that significantly improved from MRE 1 to 2 were comb sign from 63% (N=37) to 38% (N=14) (p=0.02) and penetrating disease from 14% (N=8) to 0 (p=0.03). After a median of 17 months (IQR 13–23), 51% (N=18) of patients improved, 29% (N=10) worsened and 20% (N=7) had no change based on the radiologist’s global assessment. Of the 21 patients with moderate/severe disease at MRE 1, 33% (N=7) had minimal/mild disease by MRE 2. 66% (N=14/21) continued to have moderate/severe disease at MRE 2. Additionally, a further 14% (N=2/14) of those with minimal/mild disease at baseline MRE progressed to moderate/severe disease at MRE 2. Complete details of change between MRE 1 and MRE 2 are displayed in Figure 1.

Conclusions

Despite signs of clinical improvement, many paediatric CD patients on maintenance MTX therapy for &gt;4 months have unchanged or worsened MRE findings. This underscores the need for follow-up imaging in these cases.

Funding Agencies

None

A218 LISTERIA MONOCYTOGENES MENINGITIS IN A NEWLY DIAGNOSED PATIENT WITH INFLAMMATORY BOWEL DISEASE: A CASE REPORT

Background

Anti-Tumor Necrosis Factor (TNF) is a frequently utilized therapy in the treatment of Inflammatory Bowel Disease (IBD). Opportunistic infections are a known but an infrequently encountered complication. Listeria monocytogenes (LM) is an aerobic gram-positive intracellular bacillus. Clinical presentation of infection is host dependent, ranging from self-limited illnesses in immunocompetent individuals to life-threatening sepsis and meningitis in the immunocompromised. TNF plays a crucial role in host’s defense against LM. Although published in adults, few case reports have documented invasive LM in children receiving infliximab (IFX), an anti-TNF agent used in IBD therapy.

Aims

Describe an adolescent with IBD-unclassified (IBD-U) in whom LM sepsis and meningitis was diagnosed after induction therapy with intravenous (IV) IFX.

Methods

Case report and literature review.

Results

A 15-year-old girl presented with 2-week history of progressive abdominal pain, bloody diarrhea, urgency, nocturnal stooling, tenesmus, and weight loss. She had been afebrile, with no history of exposures. Examination revealed pallor and tenderness in the right and left lower quadrants. Investigations showed elevated white cell count (WBC), platelets, inflammatory markers, and low albumin. Abdominal ultrasound showed thickening of the descending and sigmoid colon. Stool multiplex PCR was negative. Colonoscopy showed Mayo 3 pancolitis. The terminal ileum was not intubated and endoscopy was normal. She was diagnosed with IBD-U. Due to poor response to high dose IV steroids, IV IFX (after documenting normal vaccination titers) was given with good clinical response and no adverse effects; she was discharged on tapering prednisone. She re-presented 3 days later with fever, severe headaches, photophobia, and neck stiffness. Her IBD remained quiescent. She had consumed a cold meat sandwich 10 days prior. Antibiotics were started as investigations showed leukocytosis and very high inflammatory markers. Brain MRI showed pus in the lateral ventricles. Cerebrospinal fluid (CSF) analysis showed WBC 1832 x106/L, low glucose, and high protein. Blood and CSF cultures detected LM. She defervesced within 24 hours and completed a 21-day course of Ampicillin monotherapy. 2-month follow up showed IBD in continuous remission on IFX with no neurological sequalae, and a normal brain MRI.

Conclusions

This is the youngest patient with IBD reported with invasive listeriosis secondary to IFX and adds to 3 cases in children. It highlights the importance of vigilance when evaluating IBD patients with fever during IFX-based therapy. Physicians should be reminded of such patients’ immunocompromised state and their high risk of acquiring opportunistic infections. It is unclear if listeriosis avoidance precautions, currently recommended in pregnant women, should be adopted in patients receiving anti-TNF therapy.

Funding Agencies

None

Health burden of co-morbid asthma and allergic rhinitis in West Indian children

BACKGROUND

Co-morbid allergic rhinitis (AR) and asthma has not been studied in Caribbean countries where there is a high prevalence of childhood asthma.

METHODS

Using the International Primary Care Airways Group (IPAG) guidelines to determine AR, care-givers of 393 (response rate=100%) children attending asthma clinics in selected public sector health facilities in Trinidad, West Indies, were interviewed.

RESULTS

Children (393) were between 2-17 years and included 239 (60.8%) boys and 154 (39.2%) girls. As many as 53.9% of children sampled (95% CI 45.9-55.8) suffered from AR. Children exposed to household smoking were nearly twice as likely to have AR (p<0.0041, OR=1.9, CI 1.22-2.88). Significantly (p<0.01) more asthmatics with AR (154, 58.6%) visited Accident and Emergency (A&E) in the past 12 months. The odds of visiting A&E at least once in the past 12 months for asthmatics with AR were 1.75 (95% CI 1.15-2.68). The average frequency of A&E visits was higher in children who also suffered from AR (1.75 vs 1.36, p<0.04). Age was negatively correlated (-0.21, p<0.005) with exacerbation frequency for asthmatics without AR suggesting A&E visits are independent of age in co-morbid disease. More children with AR (>60%) suffer day and night symptoms (p<0.001), and miss school (59.8%) (p<0.03) at least once a week (p<0.002) than asthmatics without AR (OR=1.5, 95% CI=1.03-2.30).

CONCLUSIONS

AR is prevalent in 53.9% of Trinidadian children with asthma. The burden of co-morbid disease in asthmatic children is associated with increased likelihood of asthma-related A&E visits, day and night symptoms and absence from school.

Accreditation of medical training in Australia and New Zealand

The Australian Medical Council (AMC) accredits both Australian and New Zealand (NZ) medical courses and also college specialist training programmes. The common accreditation process allows mutual recognition of basic medical training and vocational training between Australia and New Zealand. The ultimate purpose of accreditation assure stakeholders including medical registration boards, health departments, students/trainees and the general community of the quality of the programs and the competence of those completing such training. AMC revised its own accreditation guidelines using the WFME standards as the model around which the new AMC standards were developed. The College Accreditation Process is similar to and builds on AMC experience in the medical school accreditation process. In conclusion, AMC accreditation has been successful in improving medical education in Australia and New Zealand and has been able to do so without the imposition of any exclusive educational model or philosophy.

Characterization of the B12- and iron-sulfur-containing reductive dehalogenase from Desulfitobacterium chlororespirans

The United Nations and the U.S. Environmental Protection Agency have identified a variety of chlorinated aromatics that constitute a significant health and environmental risk as "priority organic pollutants," the so-called "dirty dozen." Microbes have evolved the ability to utilize chlorinated aromatics as terminal electron acceptors in an energy-generating process called dehalorespiration. In this process, a reductive dehalogenase (CprA), couples the oxidation of an electron donor to the reductive elimination of chloride. We have characterized the B12 and iron-sulfur cluster-containing 3-chloro-4-hydroxybenzoate reductive dehalogenase from Desulfitobacterium chlororespirans. By defining the substrate and inhibitor specificity for the dehalogenase, the enzyme was found to require an hydroxyl group ortho to the halide. Inhibition studies indicate that the hydroxyl group is required for substrate binding. The carboxyl group can be replaced by other functionalities, e.g. acetyl or halide groups, ortho or meta to the chloride to be eliminated. The purified D. chlororespirans enzyme could dechlorinate an hydroxylated PCB (3,3',5,5'-tetrachloro-4,4'-biphenyldiol) at a rate about 1% of that with 3-chloro-4-hydroxybenzoate. Solvent deuterium isotope effect studies indicate that transfer of a single proton is partially rate-limiting in the dehalogenation reaction.

Analysis of hepatitis B viral load decline under potent therapy: complex decay profiles observed

We used a new real-time polymerase chain reaction (PCR)-based assay that is sensitive, has a wide dynamic linear range, and is highly reproducible to quantify hepatitis B virus (HBV) DNA in the serum of infected individuals undergoing potent antiviral therapy. In addition, we made frequent measurements of viral load after initiation of treatment and maintained follow-up to about 12 weeks. To analyze the data we used a new model of HBV decay, which takes into account that existing drug treatments do not completely block de novo infection and the possibility of noncytolytic loss of infected cells. On initiation of therapy, there was a mean delay of 1.6 days followed by a biphasic or muliphasic decay of plasma HBV DNA. The slope of the first phase varied considerably, with one individual having rapid decay, corresponding to a virion half-life of 1 hour, but others showing half-lives of up to 92 hours. Individuals either had a slow second-phase decline (t((1/2)) = 7.2 +/- 1.2 days) or a flat second phase. Some individuals exhibited a complex "staircase pattern" of decay, with further phases of viral DNA decline and phases with little change in viral load.

Australian Medical Council: a view from the inside

Although it has an important role in maintaining medical standards, little is known about the work of the Australian Medical Council (AMC) by members of the medical profession. A non-statutory standards authority, the AMC accredits medical schools in Australia and New Zealand, examines overseas-trained doctors for registration purposes and advises Medical Boards and Health Ministers on registration issues. The AMC, in consultation with Specialist Medical Colleges and others, is currently working on a number of initiatives to ensure standards of medical training and practice, including procedures to recognize new specialties and to accredit externally specialist education and training courses.

Mumps outbreak confined to a religious community

One hundred and forty-four cases of mumps were notified in a religious community in London between July 1998 and April 1999 and the infection was confirmed in 82% of those who underwent saliva testing (51/62). Half of the clinical and half of the confirme

An unusual abdominal mass

Images

A multiyear workplace-monitoring program for refractory ceramic fibers: findings and conclusions

Results of a monitoring program carried out by members of the Refractory Ceramic Fibers Coalition as part of a Consent Agreement with the U.S. Environmental Protection Agency to measure workplace concentrations of refractory ceramic fiber (RCF) are presented. More than 700 personal monitoring samples were collected and analyzed annually from workers in RCF production and processing plants, as well as from those employed by customers/end users. The data indicate that (i) approximately 90% of time-weighted average (TWA) workplace concentrations are below the industry's recommended exposure guideline of 1 fiber per cubic centimeter TWA; (ii) workplace concentrations vary with functional job category; (iii) concentrations are approximately lognormally distributed; (iv) workplace concentrations are generally decreasing; (v) there are significant differences in workplace concentrations among plants operated by both RCF producers and customers; (vi) equations can be developed to interconvert data analyzed using different measurement techniques and counting rules; (vii) usage of respirators varies with the functional job category of the worker and the average fiber concentration; and (viii) workplace samples differ from those used in animal inhalation experiments in terms of the ratio of respirable particles to fibers.

Baseline and follow-up MRI of the internal auditory canal after suboccipital resection of acoustic schwannoma: appearances and clinical correlations

Prospective baseline MRI was obtained on 31 patients who had "total" removal of acoustic schwannoma 6 months to 9 years previously. Follow-up MRI was performed after 1-2 years on patients with questionable abnormalities. We found four patterns (1) internal auditory canals (IAC) with nonenhancing soft-tissue strands, possibly scars or distorted residual nerves (8); (2) IAC with marginal enhancement-reactive dura mater (16); (3) IAC with contrast-enhancing globular tissues suggesting residual or recurrent tumour (5); (4) high-signal intensity in the IAC before contrast medium administration, probably related to graft with fat/fascia/muscle (2). Prospective 1-to 2-year follow-up studies were available in 8, 5, and 1 patients in groups 2, 3, and 4 respectively. In group 2, dural enhancement remained unchanged in 5 patients and decreased in 3. In group 3 follow-up showed 1 tumour recurrence (surgically confirmed) and 4 stable abnormalities. In group 4, follow-up in 1 of the 2 patients was stable. In groups 1 and 2, the MRI features correlate well with complete tumor removal. Whether follow-up in these groups is indicated needs to be determined. In group 3 residual or recurrent tumor cannot be excluded. In group 4, grafts may prevent adequate visualization of the IAC.

A multiyear workplace-monitoring program for refractory ceramic fibers

This paper summarizes interim results of a 5-year workplace monitoring program conducted by firms belonging to the Refractory Ceramic Fibers Coalition (RCFC) pursuant to a Consent Agreement with the U.S. EPA. The exposure monitoring program is part of a model Product Stewardship Program (PSP) developed by RCFC. This paper reviews the refractory ceramic fiber (RCF) industry, findings of animal bioassay and epidemiological investigations, and the regulatory approach used by EPA. The scope, protocols, sample collection budgets, and experimental design of the monitoring program are summarized. In brief, the program will gather 720 time-weighted average (TWA) workplace concentration measurements annually, partitioned among 8 functional job classifications, both from plants that manufacture and from those that process or use RCF. Statistical analyses reveal that: workplace airborne RCF concentration data are approximately log-normally distributed, 93% of workplace TWAs are beneath the industry's recommended exposure guideline of 1 fiber per cubic centimeter (f/cc), there are significant differences in average workplace RCF concentrations among job types, and PSP activities are effective in lowering workplace exposure. Results of this effort provide an interesting illustration of a successful cooperative effort between a responsible industry and regulatory agencies.

An examination of Penicillium notatum for the presence of Penicillium chrysogenum-type virus particles

Virus-like particles have been shown to be present in all strains of Penicillium chrysogenum examined but not in penicillin producing strains of P. notatum. Attempts to "cure" P. chrysogenum of the virus infection were not successful, nor was it possible to infect P. notatum with the purified virus from P. chrysogenum. Examination of longitudinal sections of the mycelia of P. chrysogenum showed that the virus particles are enclosed in vesicles in the infected cells.

Virus-like particles in abnormal cells of Saccharomyces carlsbergensis

An electron microscope investigation of abnormal vegetative cells and asci of a strain of Saccharomyces carlsbergensis has revealed virus-like particles with a slightly elongated hexagonal head measuring 80 × 70 mμ and a tail of the same length or slightly shorter than the longitudinal axis of the head.