The effects of nateglinide following oral glucose load in impaired glucose tolerance subjects: rapid insulin stimulation by nateglinide in IGT subjects

Ingestion of an exogenous ketone monoester improves the glycemic response during oral glucose tolerance test in individuals with impaired glucose tolerance: A cross-over randomized trial

AIMS/INTRODUCTION

As a low-carbohydrate diet and the use of sodium-glucose transporter-2 inhibitors are both known to increase D-beta-hydroxybutyrate levels, the effect of these levels on glucose metabolism has attracted attention. We investigated the acute effects of ketone monoester (KM) ingestion on blood glucose levels during the 75-g oral glucose tolerance test (OGTT) in participants with impaired glucose tolerance.

MATERIALS AND METHODS

Nine Japanese adults aged 48-62 years (4 men, 5 women) with impaired glucose tolerance participated in this study. After participants fasted overnight, we carried out OGTT for 180 min with and without KM ingestion on two separate days in a randomized cross-over design. We compared the area under the curve (AUC) of D-beta-hydroxybutyrate, glucose, insulin, C-peptide, glucagon and free fatty acids during OGTT.

RESULTS

The AUC of D-beta-hydroxybutyrate during OGTT was significantly higher with KM than without KM (KM 5995.3 ± 1257.1 mmol/L·h; without KM 116.1 ± 33.9 mmol/L·h, P < 0.0001), and the AUC of glucose with KM was significantly lower than that without KM (KM 406.6 ± 70.6 mg/dL·h; without KM 483.2 ± 74.3 mg/dL·h, P < 0.0001). This improved glucose excursion was associated with enhanced AUC of insulin during the first half (0-90 min) of OGTT, even though the AUC of C-peptide during this period was unchanged. In contrast, the AUC of insulin, C-peptide, glucagon and free fatty acids during 180 min of OGTT were similar in both conditions.

CONCLUSION

The ingestion of KM decreased the AUC of glucose during 75-g OGTT in Japanese individuals with impaired glucose tolerance, and the mechanism might involve elevated levels of circulating early phase insulin.

Insulin secretagogues for prevention or delay of type 2 diabetes mellitus and its associated complications in persons at increased risk for the development of type 2 diabetes mellitus

BACKGROUND

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether insulin secretagogues (sulphonylureas and meglitinide analogues) are able to prevent or delay T2DM and its associated complications in people at risk for the development of T2DM is unknown.

OBJECTIVES

To assess the effects of insulin secretagogues on the prevention or delay of T2DM and its associated complications in people with impaired glucose tolerance, impaired fasting blood glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was April 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a duration of 12 weeks or more comparing insulin secretagogues with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with impaired fasting glucose, impaired glucose tolerance, moderately elevated HbA1c or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles/records, assessed quality and extracted outcome data independently. One review author extracted data which were checked by a second review author. We resolved discrepancies by consensus or the involvement of a third review author. For meta-analyses we used a random-effects model with investigation of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We carried out trial sequential analyses (TSAs) for all outcomes that could be meta-analysed. We assessed the overall quality of the evidence by using the GRADE instrument.

MAIN RESULTS

We included six RCTs with 10,018 participants; 4791 participants with data on allocation to intervention groups were randomised to a second- or third-generation sulphonylurea or a meglitinide analogue as monotherapy and 29 participants were randomised to a second-generation sulphonylurea plus metformin. Three trials investigated a second-generation sulphonylurea, two trials investigated a third-generation sulphonylurea and one trial a meglitinide analogue. A total of 4873 participants with data on allocation to control groups were randomised to a comparator group; 4820 participants were randomised to placebo, 23 to diet and exercise, and 30 participants to metformin monotherapy. One RCT of nateglinide contributed 95% of all participants. The duration of the intervention varied from six months to five years. We judged none of the included trials as at low risk of bias for all 'Risk of bias' domains.All-cause and cardiovascular mortality following sulphonylurea (glimepiride) treatment were rarely observed (very low-quality evidence). The RR for incidence of T2DM comparing glimepiride monotherapy with placebo was 0.75; 95% CI 0.54 to 1.04; P = 0.08; 2 trials; 307 participants; very low-quality evidence. One of the trials reporting on the incidence of T2DM did not define the diagnostic criteria used. The other trial diagnosed T2DM as two consecutive fasting blood glucose values ≥ 6.1 mmol/L. TSA showed that only 4.5% of the diversity-adjusted required information size was accrued so far. No trial reported data on serious adverse events, non-fatal myocardial infarction (MI), non-fatal stroke, congestive heart failure (HF), health-related quality of life or socioeconomic effects.One trial with a follow-up of five years compared a meglitinide analogue (nateglinide) with placebo. A total of 310/4645 (6.7%) participants allocated to nateglinide died compared with 312/4661 (6.7%) participants allocated to placebo (hazard ratio (HR) 1.00; 95% CI 0.85 to 1.17; P = 0.98; moderate-quality evidence). The two main criteria for diagnosing T2DM were a fasting plasma glucose level ≥ 7.0 mmol/L or a 2-hour post challenge glucose ≥ 11.1 mmol/L. T2DM developed in 1674/4645 (36.0%) participants in the nateglinide group and in 1580/4661 (33.9%) in the placebo group (HR 1.07; 95% CI 1.00 to 1.15; P = 0.05; moderate-quality evidence). One or more serious adverse event was reported in 2066/4602 (44.9%) participants allocated to nateglinide compared with 2089/4599 (45.6%) participants allocated to placebo. A total of 126/4645 (2.7%) participants allocated to nateglinide died because of cardiovascular disease compared with 118/4661 (2.5%) participants allocated to placebo (HR 1.07; 95% CI 0.83 to 1.38; P = 0.60; moderate-quality evidence). Comparing participants receiving nateglinide with those receiving placebo for the outcomes MI, non-fatal stroke and HF gave the following event rates: MI 116/4645 (2.5%) versus 122/4661 (2.6%), stroke 100/4645 (2.2%) versus 110/4661 (2.4%) and numbers hospitalised for HF 85/4645 (1.8%) versus 100/4661 (2.1%) - (HR 0.85; 95% CI 0.64 to 1.14; P = 0.27). The quality of the evidence was moderate for all these outcomes. Health-related quality of life or socioeconomic effects were not reported.

AUTHORS' CONCLUSIONS

There is insufficient evidence to demonstrate whether insulin secretagogues compared mainly with placebo reduce the risk of developing T2DM and its associated complications in people at increased risk for the development of T2DM. Most trials did not investigate patient-important outcomes.

Efficacy and safety of nateglinide plus vildagliptin combination therapy compared with switching to vildagliptin in type 2 diabetes patients inadequately controlled with nateglinide

Aims/Introduction

To investigate the efficacy and safety of vildagliptin, a potent dipeptidyl peptidase‐4 inhibitor, as add‐on to nateglinide, compared with switching to vildagliptin in Japanese type 2 diabetes patients poorly controlled with nateglinide.

Materials and Methods

A total of 40 patients inadequately controlled with nateglinide were randomized to the switching group (n = 20, switching from nateglinide to vildagliptin) or combination group (n = 20, nateglinide plus vildagliptin). A meal tolerance test was carried out at weeks 0 and 24.

Results

The mean changes in glycated hemoglobin from baseline to week 24 were −1.2 ± 0.3% and −0.3 ± 0.5% in patients of the combination and switching groups, respectively, and the difference between the groups was statistically significant (P < 0.001). The mean changes in area under the curve of glucose from 0 to 180 min (AUC_0–180 min) from baseline to week 24 was −361 ± 271.3 mmol·min/L in patients of the combination group compared with 141 ± 241.9 mmol·min/L in those of the switching group (P < 0.001). The incidence of hypoglycemic events was low (three in the combination group), and none of the patients developed severe hypoglycemia. Although the addition of vildagliptin to nateglinide did not significantly increase insulin secretion relative to glucose elevation (ISG) after meal load (ISG_0–180 min: AUC_0–180 min insulin / AUC_0–180 min glucose) in comparison with that in baseline, the mean ISG_0–30 min 24 weeks after addition of vildagliptin to nateglinide was significantly higher than that at baseline. In contrast, switching from nateglinide to vildagliptin reduced the mean ISG_0–180 min, relative to baseline.

Conclusions

The combination therapy of vildagliptin and nateglinide is effective and safe in Japanese type 2 diabetes, and the improved glycemic control is as a result of augmentation of nateglinide‐induced early phase insulin secretion. This trial was registered with UMIN (no. ID000004010).

Effects of glucose load and nateglinide intervention on endothelial function and oxidative stress

We analysed endothelial function and oxidative stress in patients with abnormal glucose metabolism, the effect of glucose load, and the impact of nateglinide. 109 participants were grouped into newly diagnosed diabetes, prediabetes, and control. Fasting plasma glucose (FPG), postprandial plasma glucose (PPG), glycosylated haemoglobin (HbA1c), and glycated albumin (GA) varied significantly among the study groups (P < 0.01). Nitric oxide (NO) and insulin resistance index (HOMA-IRI) levels were markedly different between the newly diagnosed diabetes and the control (P < 0.01). Glucose loading lowered flow-mediated endothelium-dependent dilation (FMEDD), NO, and superoxide dismutase (SOD) (P < 0.01). Fasting and glucose loading FMEDD, FPG, PPG, HbA1c, and GA were negatively correlated (r = -0.4573, -0.4602, -0.3895, -0.3897, and r = -0.4594, -0.4803, -0.4494, -0.3885; P < 0.01), whereas NO, SOD, and HOMA- β were positively correlated (r = 0.2983, 0.3211, 0.311, and r = 0.1954, 0.361, 0.2569; P < 0.05). After the treatment with nateglinide, significant decreases in FPG, PPG, GA, HbA1C, endothelin-1(ET-1), malondialdehyde (MDA), and HOMA-IRI were observed, whereas FMEDD, NO, and SOD increased (P < 0.01). Thus, the study demonstrated the adverse effect of glucose load on endothelial function and oxidative stress. Nateglinide lowers blood glucose, reduces insulin resistance and oxidative stress, and improves endothelial function in newly diagnosed diabetes.

Glucose levels during oral glucose tolerance tests and gamma-glutamyl transpeptidase are predictors of change from normal to impaired glucose tolerance in healthy middle-aged Japanese men

We evaluated the predictors of the development from normal to impaired glucose tolerance (IGT) in healthy middle-aged Japanese men. Forty male subjects who showed normal glucose tolerance (NGT) levels based on WHO criteria and who had undergone 75-g OGTT annually for 10 years were selected in the database of medical checkups retrospectively, and divided into two groups: those retaining NGT and those that developed IGT. Gamma-glutamyl transpeptidase (GGT) and the glucose levels at 30 and 60 min were significantly associated with the development of IGT in the Cox proportional hazard model. However, other clinical characteristics and the glucose levels at pre-load and at 120 min were not significantly associated with the development of IGT. GGT and the glucose levels at 30 and 60 min after the 75-g glucose load were predictors of development from NGT to IGT in healthy middle-aged Japanese men.

Nateglinide reduces carotid intima-media thickening in type 2 diabetic patients under good glycemic control

OBJECTIVE

Postprandial hyperglycemia observed in type 2 diabetes mellitus is a risk factor for atherosclerosis. The aim of this study was to investigate the effect of strict glycemic control by nateglinide on common carotid far wall intima-media thickness in type 2 diabetic patients who were already under good glycemic control.

METHODS AND RESULTS

We performed an open labeled randomized prospective trial on 78 drug-naive type 2 diabetic patients whose HbA1c was less than 6.5%. Thirty-eight patients were randomly assigned to receive nateglinide (270 mg/dL) and 40 to control group (no treatment). After 12 months, a significant reduction in HbA1c was observed in the nateglinide group, whereas a significant increase of HbA1c was observed in the untreated group. The carotid intima-media thickness at the end of 1-year follow-up was significantly reduced in the nateglinide group compared with the untreated group (-0.017+/-0.054 mm/year versus 0.024+/-0.066 mm/year, P=0.0064). Whereas nateglinide treatment also reduced triglyceride, highly-sensitive C-reactive protein, and E-selectin, multiple regression analysis identified HbA1c as the only significant independent determinant of the change in carotid intima-media thickness.

CONCLUSION

In type 2 diabetic patients with good glycemic control, further strict glycemic control by nateglinide results in regression of carotid intima-media thickness.

Long-term effect of combination therapy with mitiglinide and once daily insulin glargine in patients who were successfully switched from intensive insulin therapy in short-term study

We have previously reported the therapeutic efficacy of mitiglinide combined with once daily insulin glargine (mitiglinide regimen) after switching from multiple daily insulin regimen of aspart insulin and glargine (intensive insulin regimen) in inpatients with type 2 diabetes mellitus in two consecutive days. In the present study, we followed up 9 of the 15 responsive patients with these novel regimens for 6 months after discharge. The data collected from these patients were compared to those of 15 randomly chosen patients who had well matched background and received intensive insulin regimen during hospitalization which was continued after discharge. The average HbA1c level of these 9 patients with mitiglinide regimen at 6 months was 6.7 +/- 0.8% and was comparable to that of the patients with intensive insulin regimen (HbA1c = 7.0 +/- 1.0%). In conclusion, mitiglinide and insulin glargine combination therapy maintained fair glycemic control for as long as 6 months in subpopulation of Japanese patients with type 2 diabetes.

Efficacy and adverse effects of nateglinide in early type 2 diabetes. Comparison with voglibose in a cross-over study

An open-label prospective cross-over trial was performed to compare the efficacy and adverse effects of nateglinide with those of voglibose on Japanese early type 2 diabetes (who were oral hypoglycemic agent naïve and whose HbA(1C) levels were between 7.0 and 7.9% before treatment). Fourteen patients received 270 mg/day of nateglinide and 15 patients received 0.6 mg/day of voglibose. After 12 weeks of either therapy, the drugs were switched and treatment was continued for another 12 weeks. After 3-month treatment with each drug, HbA(1C) value decreased significantly (baseline HbA(1C) 7.24 +/- 0.42%, 6.70 +/- 0.47% with nateglinide: p<0.01, 6.93 +/- 0.62% with voglibose: p<0.05) but the difference in the effect between nateglinide and voglibose was not significant (p = 0.121). Symptoms related to hypoglycemia (e.g., increased appetite, palpitation, sweating, tremor) were scarcely observed with either voglibose or nateglinide treatments. Abdominal fullness/borborygmi was frequently reported, with variable severity, by patients on voglibose but this was absent or mild in those on nateglinide. After completion of both arms of the study, more patients favored nateglinide than voglibose. Our results suggest that nateglinide is an effective and safe drug in the treatment of early type 2 diabetes, similar to voglibose.

Therapeutic efficacy of mitiglinide combined with once daily insulin glargine after switching from multiple daily insulin regimen of aspart insulin and glargine in patients with type 2 diabetes mellitus

Mitiglinide is novel class of rapid-acting insulin secretagogues, which have been widely used alone or in combination with other oral hypoglycemic drugs to improve postprandial hyperglycemia in early type 2 diabetes. While mitiglinide enhances postprandial requirement of insulin, the efficacy of mitiglinide combined with insulin has yet to be established. We investigated the efficacy of mitiglinide combined with insulin glargine, the first soluble insulin analog that has a flat and prolonged effect. After control with the intensive regimen (daily aspart insulin and glargine), 30 inpatients with type 2 diabetes were switched to premeal mitiglinide combined with once daily insulin glargine (mitiglinide regimen), and daily profiles of blood glucose level were compared under each regimen. Fifteen patients showed similar control of hyperglycemia with mitiglinide regimen and intensive insulin regimen, assessed by M value (<32), while the remaining 15 showed worsening under the mitiglinide regimen. The patients who were well controlled with mitiglinide regimen were significantly younger (51.9 +/- 16.0 years, p<0.005) and heavier (body mass index: 25.7 +/- 3.3 kg/m(2), p<0.05) than those who were not (67.9 +/- 8.7 and 23.0 +/- 3.1, respectively). Moreover, insulin doses of aspart per body weight were significantly fewer in effective group than in ineffective group. Duration of diabetes was shorter in the effective group, albeit insignificantly. Previous treatment before starting intensive insulin regimen, such as insulin and sulfonylurea, was not different between the two groups. Our results suggest that mitiglinide plus insulin glargine combination therapy is useful for lowering both fasting and postprandial hyperglycemia in a subpopulation of type 2 diabetes. The long-term effects of such treatment need to be established in future studies.

Characteristics of Japanese subjects who progress from normal to impaired glucose tolerance. Longitudinal study excluding changes in body weight

In this retrospective longitudinal study, we focused on the clinical characteristics of Japanese individuals with recent onset impaired glucose tolerance (IGT) who have been followed up for insulin secretory function and 75-gram oral glucose tolerance test (OGTT) for more than 3 years annually before they progressed from normal glucose tolerance (NGT) to IGT. Subjects whose body weight did not show significant change for the period were selected and labeled as either NGT (no change in OGTT over 3 years) or IGT (progressors from NGT to IGT) groups (n = 24, each). We compared the basal biochemical data and response of plasma glucose and serum insulin after OGTT of the two groups. In the IGT progressors, significant increase of plasma glucose at 30 to 120 minutes during OGTT and significant decrease of HDL-cholesterol were observed since 3 years before onset of IGT. In addition to increase of serum glucose and decrease of HDL-cholesterol, serum insulin at 120 minutes during OGTT were significantly and remarkably high at onset and 3 years before onset of IGT. Plasma glucose at 30-120 minutes and serum insulin level at 120 minutes after glucose load are potentially significant predictors of progression from NGT to IGT even in subjects who do not show increase of body weight.

Nateglinide--current and future role in the treatment of patients with type 2 diabetes mellitus

Therapy for type 2 diabetes mellitus should aim to control not only fasting, but also postprandial glucose levels. Nateglinide, a d-phenylalanine derivative, restores postprandial early phase insulin secretion in a transient and glucose-sensitive manner without affecting basal insulin levels. As nateglinide is administered immediately before meals it provides greater lifestyle flexibility than agents that require patients to eat to avoid hypoglycemic events (e.g. long-acting sulfonylureas). In randomised, double-blind trials in patients with type 2 diabetes, nateglinide monotherapy (mealtime treatment of 120 mg three times daily) significantly improved long-term glycaemic control by significantly reducing glyated haemoglobin (HbA 1c) and preventing mealtime glucose spikes. The combination of nateglinide with insulin-sensitising agents, for example, metformin and thiazolidinediones, addresses the dual defects of loss of insulin secretion and insulin resistance to provide optimal management of type 2 diabetes, and more patients achieve HbA 1c goal with nateglinide combination therapy rather than with monotherapy with other oral agents. Nateglinide also restores early insulin secretion and reduces postprandial hyperglycaemia in prediabetic subjects with impaired glucose tolerance (IGT) and appears similarly effective in elderly and non-elderly populations with type 2 diabetes. It has an excellent safety and tolerability profile, with a low propensity to cause hypoglycaemia due to its transient, selective effect on early phase insulin secretion. Nateglinide as monotherapy or combination therapy is an effective option to reduce mealtime glucose in patients with type 2 diabetes. The results of ongoing research into its potential role in delaying progression to overt diabetes, and protecting against cardiovascular events, in prediabetic patients with IGT are awaited.

The effect of defective early phase insulin secretion on postload glucose intolerance in impaired fasting glucose

Impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) are two risk groups for type 2 diabetes. Type 2 diabetes is characterized by both impaired insulin secretion and insulin resistance but their relative contribution to the development of hyperglycemia may differ due to heterogeneity of the disease. Combined glucose intolerance (CGI), on the other hand, seems to represent a more advanced stage of prediabetes that bears a distinctly higher risk of progression to diabetes and its comorbidities. This study has the aim to compare isolated IFG and CGI categories with respect to the degree of early phase insulin secretion abnormalities and insulin resistance. Subjects who had IFG (fasting glucose: 110-126 mg/dl) were included in the study. A 75-g oral glucose tolerance test (OGTT) with insulin response was done and subjects were classified according to the WHO criteria. Six subjects were excluded because they had diabetic glucose tolerance. A total of 66 patients (53.4 +/- 11.1 years, female/male: 48/18) were divided into two groups according to their glucose tolerance in OGGT (Group 1: isolated IFG and group 2: CGI). Early phase insulin secretion was measured by intravenous glucose tolerance test (IVGTT) and OGTT. Insulin resistance was assessed by the R value of the homeostasis model assessment (HOMA). We did not find any statistically significant difference between groups according to age, gender, body mass index (BMI), fasting glucose, fasting insulin, insulin-AUC (0-180 min) and HOMA-R values. In OGGT there was no statistically significant difference between 0', 30', 60' and 90' insulin levels of the groups; only 120' and 180' insulin levels were higher in CGI than in IFG group (p<0.05). In IVGTT, there was no statistically significant difference between glucose levels of the groups. Furthermore, insulin response to intravenous glucose was higher in IFG than in CGI (p<0.05). Our data demonstrate that isolated IFG and CGI are similar with respect to the degree of insulin resistance, and that subjects with CGI had a more prominent deficit in early phases of insulin secretion.

Diabetes in Japan

In this article, we introduce the increasing prevalence of type 2 diabetes in the Japanese population and discuss the reasons for such an explosive increase. Diabetes has been brought into prominence in Japan by enhanced insulin resistance, through the change of lifestyle against the background of fragile beta-cell function and thrifty genotypes.

Effect of cilostazol, a phosphodiesterase inhibitor, on carotid IMT in Japanese type 2 diabetic patients

The aim of this study was to investigate the effect of cilostazol, a cAMP phosphodiesterase inhibitor, on carotid artery intima-media thickness (IMT) and on the incidence of cardiovascular events in Japanese subjects with type 2 diabetes. A total of 62 type 2 diabetic subjects were allocated equally to the cilostazol treatment group (n = 31) and the control group (n = 31). Carotid IMT was evaluated before and after treatment using B-mode ultrasonography. After the study period (mean +/- SD: 2.6 +/- 0.17 years), carotid IMT showed a significantly greater increase in the control group than in the cilostazol group (0.12 +/- 0.14 mm vs. 0.04 +/- 0.02 mm, p < 0.05). In the control group, 1 out of 31 patients suffered from symptomatic cerebral infarction and 1 had angina pectoris during the observation period. On the other hand, no subject in the cilostazol group developed cardiovascular events during the study period. At baseline, the diabetic patients given cilostazol had a significantly lower HbA1c level than the control subjects, but the other atherosclerotic risk factors (BMI, blood pressure, and serum lipids) and the duration of diabetes did not differ between the two groups. These results indicate that cilostazol therapy can attenuate the increase of carotid artery IMT in Japanese subjects with type 2 diabetes.

Efficacy and safety of once daily gliclazide (20 mg/day) compared with nateglinide

An open-label prospective cross-over trial was performed to compare the efficacy and safety of once daily low-dose gliclazide (20 mg/day) with that of nateglinide at the usual dosage (270 mg/day, 90 mg t.i.d.) in Japanese type 2 diabetics with relatively good glycemic control (HbA1c<7.0%). Eight patients received 20 mg/day of gliclazide and 16 received 270 mg/day of nateglinide. After at least 12 weeks of gliclazide or nateglinide therapy, the drugs were switched and treatment was continued for another 12 weeks. The final HbA1c value was modestly, but significantly, lower after gliclazide treatment than after nateglinide treatment (6.2% vs. 6.4%). However, symptoms related to hypoglycemia were significantly more common with gliclazide treatment than nateglinide treatment (7 vs. 0 cases), although there were no severe hypoglycemic events. While gliclazide acts as a free radical scavenger, there was no effect on parameters of oxidative stress such as malondialdehyde-modified low density lipoprotein and thiobarbituric acid-reactive substances at the low dosage tested. In conclusion, both drugs are reasonable options for early type 2 diabetes. Compared with the regular dose of nateglinide, 20 mg/day of gliclazide achieved modestly better glycemic control with an increased frequency of hypoglycemia in diabetic patients with relatively good glycemic control.