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.

Association Between Staphylococcus aureus Bacteremia and Hospital Mortality in Hemodialysis Patients With Bloodstream Infection: A Multicenter Cohort From Japanese Tertiary Care Centers

Multiple studies have shown that Staphylococcus aureus bacteremia (SAB) has been a major cause of death in hemodialysis patients. We examined whether SAB is a risk for mortality among chronic hemodialysis patients in Japan where the standard vascular access is arteriovenous fistula (AVF). This was a multicenter, retrospective study of maintenance hemodialysis patients with bloodstream infection (BSI) from 2011 to 2013 at tertiary care centers in Japan. The endpoint was hospital mortality. Our cohort contained 32 SAB cases (14 MRSA and 18 MSSA) and 42 non-SAB cases. Hospital mortality was higher among SAB cases than non-SAB cases (46.9% vs. 23.8%, P = 0.038). In patients with BSI, SAB was significantly associated with hospital mortality after adjustment for potential confounders, including type of vascular access (OR 3.26). S. aureus was the leading cause of BSI and hospital mortality among this cohort. Therefore, initial empiric treatment should cover for S. aureus.

Development and Validation of a Clinical Prediction Rule for Bacteremia among Maintenance Hemodialysis Patients in Outpatient Settings

Background

To our knowledge, no reliable clinical prediction rule (CPR) for identifying bacteremia in hemodialysis (HD) patients has been established. The aim of this study was to develop a CPR for bacteremia in maintenance HD patients visiting the outpatient department.

Methods

This multicenter cohort study involved consecutive maintenance HD patients who visited the outpatient clinic or emergency room of seven Japanese institutions between August 2011 and July 2013. The outcome measure was bacteremia diagnosed based on the results of blood cultures. The candidate predictors for bacteremia were extracted through a literature review. A CPR for bacteremia was developed using a coefficient-based multivariable logistic regression scoring method, and calibration was performed. The test performance was then assessed for the CPR.

Results

Of 507 patients eligible for the study, we analyzed the 293 with a complete dataset for candidate predictors. Of these 293 patients, 48 (16.4%) were diagnosed with bacteremia. At the conclusion of the deviation process, body temperature ≥ 38.3°C, heart rate ≥ 125 /min, C-reactive protein ≥ 10 mg/dL, alkaline phosphatase >360 IU/L, and no prior antibiotics use within the past week were retained and scored. The CPR had a good fit for the model on calibration. The AUC of the CPR was 0.76, and for score CPR ≥ 2, the sensitivity and specificity were 89.6% and 51.4%, respectively.

Conclusions

We established a simple CPR for bacteremia in maintenance HD patients using routinely obtained clinical information in an outpatient setting. This model may facilitate more appropriate clinical decision making.

Factors Contributing to Erythropoietin Hyporesponsiveness in Patients on Long-Term Continuous Ambulatory Peritoneal Dialysis: A Cross-Sectional Study

BACKGROUND

Factors contributing to erythropoietin (EPO) hyporesponsiveness in patients on long-term continuous ambulatory peritoneal dialysis are not well understood. Therefore, we investigated the factors contributing to EPO hyporesponsiveness using the EPO resistance index (ERI).

METHODS

A total of 14 patients (7 males and 7 females, age 65.0 ± 11.9 years) were selected for this study. We defined ERI as the weekly dose of EPO per body weight divided by hemoglobin (U/kg/g/dl/week). Bioelectrical impedance analysis was used to assess the patients' body composition and fluid status. We examined associations between ERI and clinical parameters, such as physiological, chemical and nutrition status, by correlation and multiple linear regression analyses.

RESULTS

Peritoneal dialysis duration was 95 ± 23 months, and all patients underwent peritoneal dialysis for >5 years. Hemoglobin, blood pressure and ultrafiltration volume of peritoneal dialysis were 11.5 ± 1.2 g/dl, 123 ± 14/72 ± 8 mm Hg and 834 ± 317 ml/day, respectively. Renal Kt/V and peritoneal Kt/V, which are indices of dialysis adequacy, were 0.32 ± 0.31 and 1.70 ± 0.31, respectively. Age and extracellular water/total body water (ECW/TBW) ratio had significant positive correlations with ERI (both p < 0.05). Levels of C-reactive protein, serum albumin, parathyroid hormone and normalized protein catabolic rate were not significantly correlated with ERI. In a multiple regression analysis, ECW/TBW was independently associated with ERI (p < 0.05).

CONCLUSIONS

This study demonstrates that ECW/TBW was a factor contributing to ERI and that appropriate maintenance of body fluid volume could contribute to low EPO dosing.

Nephrology pre-dialysis care affects the psychological adjustment, not only blood pressure, anemia, and phosphorus control

Several studies have suggested that pre-dialysis care is associated with clinical outcomes. However, little has been reported on the influence of pre-dialysis care on the psychological adjustment to dialysis. The purpose of this study was to evaluate the impact of pre-dialysis care on psychological adjustment to dialysis and clinical characteristics. In this cross-sectional study, we enrolled 52 patients who started hemodialysis at our hospital. They were divided into two groups according to the time of referral to our hospital: the early referral group (over 1 year prior to first dialysis: 19 patients, mean age 69.3 ± 11.1) and the late referral group (within 1 year prior to first dialysis: 33 patients, mean age 72.3 ± 8.9). We measured the clinical characteristics and evaluated the psychological adjustment to dialysis by Shontz's stage theory. Compared with the late referral group, the early referral group had a significantly better clinical characteristics concerning blood pressure (140.2 ± 23.7 vs. 156.9 ± 23.3 mmHg, P = 0.0150), hemoglobin (10.3 ± 1.5 vs. 9.4 ± 1.0 g/dL, P = 0.0078), and phosphorus (4.5 ± 1.5 vs. 5.5 ± 1.3 mg/dL, P = 0.0166). In addition, psychological adjustment to dialysis evaluated by Shontz's stage theory was significantly better in the early referral group (P = 0.017). Our results indicate that nephrology pre-dialysis care affects not only blood pressure, anemia, and phosphorus control but also the psychological adjustment to dialysis.

Diurnal variations of blood glucose by continuous blood glucose monitoring in peritoneal dialysis patients with diabetes

Exaggerated postprandial increase in blood glucose has been postulated to be associated with cardiovascular injury. The concentration of blood glucose is altered by glucose absorption from peritoneal dialysis (PD) fluids. In PD patients, we used continuous blood glucose monitoring (CGM) to analyze diurnal variations in blood glucose. Diurnal blood glucose was determined in 10 diabetic PD patients who used CGM (iPro2: Medtronic, Northridge, CA, U.S.A.) for 3 days. Blood glucose concentrations before and after glycemic control were monitored in 5 patients. Correlations between CGM parameters [standard deviation of blood glucose (SDG)], peritoneal function [dialysate-to-plasma ratio of creatinine (D/P Cr) and end-to-initial dialysate (D/D0) glucose], 24-hour peritoneal glucose absorption, and glycemic index were determined. In 5 patients, CGM was performed again after adjustments to antidiabetic drugs. A large diurnal variation, especially at night, was observed in this patient cohort. No correlation of HbA1c with mean blood glucose concentration was observed. Although SDG had no association with 24-hour peritoneal glucose absorption, it did show an association with D/P Cr and D/D0 glucose. The SDG was significantly lower after treatment with a dipeptidyl peptidase IV inhibitor or an increase in insulin dose. Results of the present study indicate that diurnal variations in glucose depend on the speed of peritoneal glucose absorption rather than the net glucose absorption.

Impact of hydration and nutrition status on the Watson formula in peritoneal dialysis patients

Urea clearance (Kt/V urea), adjusted for total body water (TBW) using the Watson formula (TBW(Watson)), is widely used to guide peritoneal dialysis (PD) prescription and to ensure dialysis adequacy. The impact of body composition on the determination of TBW(Watson) is well established, but the effect of hydration and nutrition status on TBW(Watson) is not understood. We therefore studied the effects of hydration and nutrition status on TBW(Watson) in PD patients. Our study enrolled 195 PD patients and 33 healthy control subjects. Multiple-frequency bioelectrical impedance spectroscopy (MF-BIS) was used to measure TBW and the result was compared with TBW(Watson). Patients were divided into three groups according to their degree of overhydration [deltahydration status (OH) in liters]: normally hydrated group (OH: < 2.0 L), mildly overhydrated group (OH: 2.0 - 4.0 L), and severely overhydrated group (OH: > 4.0 L). Compared with MF-BIS, the Watson formula overestimated TBW in normally hydrated patients, but underestimated TBW in severely overhydrated patients. In addition, of the normally hydrated patients, 22 were malnourished by subjective global assessment, and the TBW(Watson) overestimation was much greater in them than in the well-nourished patients. Our study suggests that hydration and nutrition status both strongly affect TBW(Watson) in PD patients.

Vildagliptin is Effective for Glycemic Control in Diabetic Patients Undergoing either Hemodialysis or Peritoneal Dialysis

INTRODUCTION

Vildagliptin can be used in patients with type 2 diabetes mellitus and renal impairment. However, there have been few reports investigating the clinical effectiveness of vildagliptin in diabetic patients undergoing hemodialysis. No previous studies have evaluated the use of vildagliptin in patients undergoing peritoneal dialysis. The authors determined the usefulness of vildagliptin for treating type 2 diabetic patients receiving chronic dialysis, including peritoneal dialysis.

METHODS

A retrospective study of ten diabetic patients undergoing peritoneal dialysis and five diabetic patients undergoing hemodialysis who were treated with 50 mg/day of vildagliptin was performed. Clinical parameters were investigated for a period of 6 months starting from the vildagliptin therapy.

RESULTS

The hemoglobin A1c (HbA1c) levels were significantly reduced after baseline in both the peritoneal dialysis and hemodialysis groups, whereas the hemoglobin levels did not change during the follow-up period. The mean change in the HbA1c level (ΔHbA1c) was -0.6 ± 0.9% and -0.5 ± 0.7% among the patients undergoing peritoneal dialysis and hemodialysis, respectively. The glycated albumin (GA) levels were also significantly reduced compared with baseline in the peritoneal dialysis group, although the serum albumin levels did not change. The mean change in the GA level (ΔGA) was -3.4 ± 3.1% and -2.1 ± 2.5% among the patients undergoing peritoneal dialysis and hemodialysis, respectively. Stepwise multivariate analyses demonstrated the level of HbA1c at baseline to be significantly associated with the ΔHbA1c and that the level of GA at baseline was significantly associated with the ΔGA.

CONCLUSION

Vildagliptin exhibits effectiveness in patients with type 2 diabetes mellitus undergoing peritoneal dialysis or hemodialysis. The degree of improvement in the HbA1c and GA levels was dependent on these levels at baseline, similar to the findings of previous reports of subjects without end-stage kidney disease.

Hypoglycemia observed during continuous glucose monitoring in patients with type 2 diabetes mellitus treated by subcutaneous insulin injection

BACKGROUND

The relationship between hypoglycemia and the dose of insulin used in patients with type 2 diabetes mellitus was investigated by continuous glucose monitoring (CGM).

PATIENTS AND METHODS

In total, 83 CGM studies were performed in 70 outpatients with type 2 diabetes receiving treatment by subcutaneous insulin injection.

RESULTS

The total dose of insulin, bolus insulin dose, and basal insulin dose used in the subjects were 32±18 units, 19±13 units, and 13±8 units, respectively. The proportion of time in the hypoglycemic range (blood glucose<3.9 mmol/L) during CGM was positively correlated with the bolus insulin ratio (bolus/total insulin dose, r=0.22, P=0.04), although it was not associated with the total dose of insulin or the hemoglobin A1c (HbA1c) level. It was negatively correlated with the mean blood glucose (r=-0.38, P<0.01), whereas it was not associated with the SD or the mean amplitude of glycemic excursions (MAGE). The proportion of time in the hypoglycemic range was significantly greater in the subjects with a bolus insulin ratio of ≥0.6 (3.2±4.4%, n=42) than a ratio of <0.6 (1.2±3.0%, n=41), although the HbA1c level, total dose of insulin, mean blood glucose, SD, and MAGE were not significantly different between the two groups.

CONCLUSIONS

An excessive dose of bolus insulin might increase the duration of hypoglycemia, independently from the HbA1c levels, in patients with type 2 diabetes mellitus receiving subcutaneous insulin injection.

The Prevalence of the Risk Factors for Atherosclerosis among Type 2 Diabetic Patients Is Greater in the Progressive Stages of Chronic Kidney Disease

BACKGROUND/AIMS

The prevalence of the risk factors for atherosclerosis, other than diabetes mellitus, among type 2 diabetic patients with different stages of chronic kidney disease (CKD) determined by glomerular filtration rate (GFR) was investigated.

METHODS

The prevalence of ten risk factors (age ≥65 years, history of smoking, male gender, obesity, albuminuria, hypertension, hypercholesterolemia, hypo-HDL-cholesterolemia, hyperuricemia and anemia) was determined in 2,107 Japanese type 2 diabetic patients with different stages of CKD (six stages according to GFR).

RESULTS

The risk factors for age ≥65 years and male gender were found in 49 and 62% of the study subjects, respectively. The percentages of subjects with a current history of smoking, obesity, albuminuria, hypertension, hypercholesterolemia, hypo-HDL-cholesterolemia, hyperuricemia and anemia were 35, 44, 47, 70, 61, 13, 21 and 26%, respectively. The prevalence of age ≥65 years, male gender, albuminuria, hypertension, hypo-HDL-cholesterolemia, hyperuricemia and anemia was greater in the later stages of GFR, whereas the prevalence of hypercholesterolemia and obesity did not differ between stages. The prevalence of a current history of smoking was lower in the later stages of GFR. The cumulative number of risk factors increased from 3.1 to 6.8 in the later stages of GFR.

CONCLUSION

Among type 2 diabetic patients with CKD, the total number of risk factors increases with the progression of renal dysfunction. It is important to pay attention to newly recognized risk factors for hyperuricemia and anemia, in addition to hypertension, albuminuria and hypo-HDL-cholesterolemia, in monitoring diabetic patients with later stages of CKD.

Left ventricular mass index is an independent determinant of diastolic dysfunction in patients on chronic hemodialysis: a tissue Doppler imaging study

BACKGROUND

Diastolic heart failure is the most common clinical form of heart failure. Tissue Doppler imaging (TDI) is often used to quantitate left ventricular (LV) diastolic function. The purpose of this study was to identify the determinant(s) of diastolic dysfunction in patients with end-stage renal disease on hemodialysis (HD), using the TDI method.

METHODS

The study subjects were 53 patients with end-stage renal disease and preserved LV systolic function on maintenance HD. LV function was assessed by conventional echocardiography. The ratio of early trans-mitral flow velocity to early mitral annular velocity (E/e') was measured by TDI. Patients were stratified into two groups based on E/e' value (≤15 and >15 groups). Arterial stiffness was evaluated by pulse wave velocity and cardio-ankle vascular index.

RESULTS

Patients of the E/e' >15 group were older (p = 0.025). There were no significant differences in blood pressure, ejection fraction, E/A, deceleration time, and pulse wave velocity between the E/e' >15 and E/e' ≤15 groups. However, there were significant differences in LV mass index (LVMI; p < 0.001) and cardio-ankle vascular index (p = 0.048) between the two groups. Multiple regression analysis identified that LVMI was an independent determinant of E/e' (p = 0.003).

CONCLUSIONS

Our findings suggest that LVMI is an independent determinant of LV diastolic dysfunction in patients on HD.

Inactivation of fibroblast growth factor receptor signaling in myelinating glial cells results in significant loss of adult spiral ganglion neurons accompanied by age-related hearing impairment

Hearing loss has been attributed to many factors, including degeneration of sensory neurons in the auditory pathway and demyelination along the cochlear nerve. Fibroblast growth factors (FGFs), which signal through four receptors (Fgfrs), are produced by auditory neurons and play a key role in embryonic development of the cochlea and in neuroprotection against sound-induced injury. However, the role of FGF signaling in the maintenance of normal auditory function in adult and aging mice remains to be elucidated. Furthermore, the contribution of glial cells, which myelinate the cochlear nerves, is poorly understood. To address these questions, we generated transgenic mice in which Fgfr1 and Fgfr2 were specifically inactivated in Schwann cells and oligodendrocytes but not in neurons. Adult mutant mice exhibited late onset of hearing impairment, which progressed markedly with age. The hearing impairment was accompanied by significant loss of myelinated spiral ganglion neurons. The pathology extended into the cochlear nucleus, without apparent loss of myelin or of the deletion-bearing glial cells themselves. This suggests that perturbation of FGF receptor-mediated glial function leads to the attenuation of glial support of neurons, leading to their loss and impairment of auditory functions. Thus, FGF/FGF receptor signaling provides a potentially novel mechanism of maintaining reciprocal interactions between neurons and glia in adult and aging animals. Dysfunction of glial cells and FGF receptor signaling may therefore be implicated in neurodegenerative hearing loss associated with normal aging.

Mice with conditional inactivation of fibroblast growth factor receptor-2 signaling in oligodendrocytes have normal myelin but display dramatic hyperactivity when combined with Cnp1 inactivation

Fibroblast growth factor receptors (Fgfr) comprise a widely expressed family of developmental regulators implicated in oligodendrocyte (OL) maturation of the CNS. Fgfr2 is expressed by OLs in myelinated fiber tracks. In vitro, Fgfr2 is highly upregulated during OL terminal differentiation, and its activation leads to enhanced growth of OL processes and the formation of myelin-like membranes. To investigate the in vivo function of Fgfr2 signaling by myelinating glial cells, we inactivated the floxed Fgfr2 gene in mice that coexpress Cre recombinase (cre) as a knock-in gene into the OL-specific 2',3'-cyclic nucleotide phosphodiesterase (Cnp1) locus. Surprisingly, no obvious defects were detected in brain development of these conditional mutants, including the number of OLs, the onset and extent of myelination, the ultrastructure of myelin, and the expression level of myelin proteins. However, unexpectedly, a subset of these conditional Fgfr2 knock-out mice that are homozygous for cre and therefore are also Cnp1 null, displayed a dramatic hyperactive behavior starting at approximately 2 weeks of age. This hyperactivity was abolished by treatment with dopamine receptor antagonists or catecholamine biosynthesis inhibitors, suggesting that the symptoms involve a dysregulation of the dopaminergic system. Although the molecular mechanisms are presently unknown, this novel mouse model of hyperactivity demonstrates the potential involvement of OLs in neuropsychiatric disorders, as well as the nonpredictable role of genetic interactions in the behavioral phenotype of mice.

Striped iron zoning of olivine induced by dislocation creep in deformed peridotites

Deformation of solid materials affects not only their microstructures, but also their microchemistries. Although chemical unmixing of initially homogeneous multicomponent solids is known to occur during deformation by diffusion creep, there has been no report on their chemical zoning due to deformation by dislocation creep, in either natural samples or laboratory experiments. Here we report striped iron zoning of olivine ((Mg,Fe)2SiO4) in deformed peridotites, where the iron concentration increases at subgrain boundaries composed of edge dislocations. We infer that this zoning is probably formed by alignment of edge dislocations dragging a so-called Cottrell 'atmosphere' of solute atoms (iron in this case) into subgrain boundaries during deformation of the olivine by dislocation creep. We have found that the iron zoning does not develop in laboratory experiments of high strain rates where dislocations move too fast to drag the Cottrell atmosphere. This phenomenon might have important implications for the generation of deep-focus earthquakes, as transformation of olivine to high-pressure phases preferentially occurs in high-iron regions, and therefore along subgrain boundaries which would be preferentially aligned in plastically deformed mantle peridotites.

Survey of recognition and utilization of guidelines for the diagnosis and management of bronchial asthma in Japan

BACKGROUND

In Japan in 1993, the Japanese Society of Allergology (JSA) developed guidelines for diagnosis and management of asthma (JGL), which were based on the concept that asthma is a chronic inflammatory disorder of the airway.

METHODS

This survey study was intended to investigate the recognition and utilization of JGL among physicians who had treated asthma. The survey comprised two methods: a quantitative mail survey and a qualitative door-to-door survey conducted by trained interviewers.

RESULTS

In the mail survey, a total of 1028 physicians responded; 552 members of the JSA and 476 nonmembers. Ninety-four percent of JSA members were aware of adult asthma management guidelines, while 53% of nonmembers were aware of them. Although approximately half of the physicians, both members and nonmembers, found differences between the asthma management policies in JGL and their previous policies, most of them utilized JGL once they read it. In the qualitative door-to-door survey, 80-90% of physicians evaluated JGL as good after they read it.

CONCLUSIONS

JGL was recognized and utilized by most JSA members, but only half of nonmember physicians were aware of JGL, although they utilized JGL after they read it. Further action to implement JGL among nonspecialist physicians is needed to improve management of asthma.