Glycemia and Gluconeogenesis With Metformin and Liraglutide: A Randomized Trial in Youth-onset Type 2 Diabetes

OBJECTIVE

Elevated rates of gluconeogenesis are an early pathogenic feature of youth-onset type 2 diabetes (Y-T2D), but targeted first-line therapies are suboptimal, especially in African American (AA) youth. We evaluated glucose-lowering mechanisms of metformin and liraglutide by measuring rates of gluconeogenesis and β-cell function after therapy in AA Y-T2D.

METHODS

In this parallel randomized clinical trial, 22 youth with Y-T2D-age 15.3 ± 2.1 years (mean ± SD), 68% female, body mass index (BMI) 40.1 ± 7.9 kg/m2, duration of diagnosis 1.8 ± 1.3 years-were randomized to metformin alone (Met) or metformin + liraglutide (Lira) (Met + Lira) and evaluated before and after 12 weeks. Stable isotope tracers were used to measure gluconeogenesis [2H2O] and glucose production [6,6-2H2]glucose after an overnight fast and during a continuous meal. β-cell function (sigma) and whole-body insulin sensitivity (mSI) were assessed during a frequently sampled 2-hour oral glucose tolerance test.

RESULTS

At baseline, gluconeogenesis, glucose production, and fasting and 2-hour glucose were comparable in both groups, though Met + Lira had higher hemoglobin A1C. Met + Lira had a greater decrease from baseline in fasting glucose (-2.0 ± 1.3 vs -0.6 ± 0.9 mmol/L, P = .008) and a greater increase in sigma (0.72 ± 0.68 vs -0.05 ± 0.71, P = .03). The change in fractional gluconeogenesis was similar between groups (Met + Lira: -0.36 ± 9.4 vs Met: 0.04 ± 12.3%, P = .9), and there were no changes in prandial gluconeogenesis or mSI. Increased glucose clearance in both groups was related to sigma (r = 0.63, P = .003) but not gluconeogenesis or mSI.

CONCLUSION

Among Y-T2D, metformin with or without liraglutide improved glycemia but did not suppress high rates of gluconeogenesis. Novel therapies that will enhance β-cell function and target the elevated rates of gluconeogenesis in Y-T2D are needed.

Epidemiology of brain tumors

After lagging behind other brain tumor disciplines in the 1980s, the epidemiology of brain tumors is now making progress on several fronts. The Central Brain Tumor Registry in the USA has made a complete description of primary brain tumors available to researchers. International data suggest that environmental components in the etiology of brain tumors are likely to be widely dispersed by geography and demographic subgroups. There are few proven causes of brain tumors: high-dose ionizing radiation, inherited genetic syndromes and AIDs-related brain lymphomas. Promising avenues of research include the role of immune function, genetic components in families, metabolic and DNA-repair pathways and neurocarcinogen exposures.

Ultrahigh-Frequency Electromagnetic Fields for Weed Control: Phytotoxicity and Selectivity

An ultrahigh-frequency electromagnetic field (2450+/-20 megahertz) is lethal to plants and seeds of several species after relatively short exposure times. Some species are highly susceptible; others are relatively resistant to a given field intensity. Phytotoxicity is increased in imbibed seeds and young plants. It is decreased in dry seeds and sometimes decreased in mature plants. Soil partially attenuates the field but is not opaque to it.

Reaction Conditions Necessary for Silylation of Herbicides

The reaction conditions are described for preparation and gas chromatographic analysis of microgram quantities of the trimethylsilyl (TMS) esters of 3,6-dichloro-o-anisic acid (dicamba), (2,4-dichlorophenoxy)acetic acid (2,4-D), (2,4,5-trichlorophenoxy)acetic acid (2,-4.5-T), and 2 water-degradable polymers of 2,4,5-T. Silylation was efficient at 0, 22, and 55°C. A ratio of 1:10 silylating agent (N,O-bis-(trimethylsilyl)acetamide, BSA) to silylation solvent (dimethylformamide, DMF) was optimum for silylation of 2,4-D, 2,4,5-T, and 2,4,5-T polymers. A 1:50 ratio was best for silylation of dicamba. A 1:10 ratio (BSA/DMF) will tolerate up to 1.0 and 0.1% water in the silylation of 2,4-D and 2,4,5-T, respectively. A 1:50 ratio will tolerate up to 0.1% water in the silylation of dicamba. Silylated samples could be analyzed immediately after addition of the silylation reagent. Stability of silylated samples at 22°C was directly proportional to concentration; 1.0 μg samples showed no loss of activity 2.3 hr after reaction. TMS esters were chromatographed on a 6′ × ¼″ glass column containing 3% SE-30 on 80-100 mesh Chromosorb W(HP) at 230°C.