Expression of human GLUT4 in mice results in increased insulin action.

Glucose metabolism was evaluated in transgenic mice expressing the human GLUT 4 glucose transporter. Fed GLUT 4 transgenic mice exhibited a 32% and 56% reduction in serum glucose and insulin and a 69% and 33% increase in non-esterified fatty acid and lactate levels, respectively. Transgenic mice exhibited a significant increase in whole-body glucose disposal during a euglycaemic-hyperinsulinaemic clamp. Insulin-stimulated glucose uptake in isolated soleus muscles and adipocytes was greater in transgenic compared to control mice due to increased basal glucose uptake. Transgenic mice displayed increased glycogen levels in liver and gastrocnemius muscle, and increased insulin-stimulated 14C-glycogen accumulation in isolated soleus muscle. We conclude that over-expression of the GLUT 4 glucose transporter in mice results in 1) an increase in whole-body glucose disposal and storage, and 2) an increase in both basal and insulin-stimulated glucose uptake and disposal in vitro. These changes resulted in the reduction of serum glucose and insulin levels. These results provide direct evidence that glucose transport (and GLUT 4 per se) plays a significant role in regulating whole-body glucose homeostasis. Additionally, these data support the idea that pharmacological strategies directed at increasing the expression of GLUT 4 protein may have beneficial (hypoglycaemic) effects in the diabetic state.

Effect of detector noise on the positioning accuracy of an autofocus system.

An autofocus system has been developed that automatically detects the presence of fringes in a white-light interference microscope and adjusts the vertical position of the microscope objective such that the focus error is minimal. The system consists of a motorized stage, a beam splitter, an optical detector, and associated electronics. In order for the interference microscope to provide accurate measurements of the optical wavefront, the error in the focus position must be small. The goal of this paper is to calculate the rms noise produced by the detector and electronics and use the results to predict the positioning error of the autofocus system.

Inhibition of hepatic glucose production by SDZ 51641.

The new oral hypoglycemic agent SDZ 51641 was evaluated in nondiabetic rats and a rat model of human non-insulin-dependent diabetes mellitus. Diabetes was induced with a single injection of 37.5 mg/kg streptozocin, and the rats exhibited hyperglycemia in the fed state with normal insulin levels. Treatment of nondiabetic animals with 100 mg/kg SDZ 51641 given orally significantly decreased serum glucose and ketone levels within 4 h without affecting insulin levels. Nonesterified fatty acids increased more than twofold during the same period. Its effect on ketone and fatty acid levels suggests that SDZ 51641 acts as an inhibitor of fatty acid oxidation. Diabetic rats treated with SDZ 51641 exhibited a significant acute hypoglycemic response, which was more pronounced after 3 days of treatment. The compound also significantly decreased serum cholesterol and triglyceride levels 27 and 53%, respectively. When endogenous hepatic glucose production was assessed in nondiabetic and diabetic animals via continuous infusion of [3-3H]glucose, we found that hepatic glucose production was elevated 43% in diabetic compared with control animals. When diabetic rats were treated with 100 mg/kg SDZ 51641, hepatic glucose production decreased to normal levels within 6 h. Hyperinsulinemic-euglycemic clamp studies indicated that SDZ 51641 had no effect on insulin-stimulated glucose utilization. Measurement of [1-14C]oleate oxidation in isolated hepatocytes demonstrated that SDZ 51641 inhibited long-chain fatty acid oxidation in a concentration-dependent manner. The compound was ineffective at inhibiting long-chain fatty acid oxidation in epitrochlearis or soleus muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin biosynthesis stimulatory and inhibitory substances in human amniotic fluid during pregnancy and labor.

Human amniotic fluid has been separated into two fractions; one fraction inhibits prostaglandin biosynthesis and the other fraction is stimulatory. The activity of the stimulatory fraction increased with increasing gestational age and was greater still during labor. The activity of the inhibitory fraction decreased with increasing gestational age and was smaller still during labor. We speculate that these changes may play a significant role in parturition.

Characteristics of a chamber used for electrooptical device performance measurements in the presence of fog.

A fog chamber, developed to support measurement of the performance of electrooptical devices in the presence of fog, is discussed. Rationale for the fog chamber concept is presented. Emphasis is placed on the theory of operation of the chamber, an optical method for assessing fog particle characteristics, and the optical properties of the different types of fog produced.

Derivation of the effect of atmospheric and aerosol emissions on IR imaging device performance.

The authors have previously called attention to the importance of atmospheric and aerosol emission in IR imaging device performance. The present paper derives a more precise and general result than the empirically derived expressions in the earlier paper. The same general conclusion, that atmospheric and aerosol emissions are an important factor in IR imaging performance, is supported, assuming that the system is photon noise-limited.

Infrared propagation and performance modeling at the Electro-Optical Test Facility.

Fog spectral transmission data generated in the Electro-Optical Test Facility and propagation models usedm by the authors are presented. Preliminary results of a modeling effort are presented that support the following conclusions: (1) atmosphere emission is a major factor in IR system performance despite the fact it is commonly omitted; (2) the 3.5-4.1-microm interval offers superior performance to the 3-5 band at both relatively short and long ranges; and (3) the longer wavelength 9.5-11.5-microm band is superior to either the 3-5 or 3.5-4.1 bands in the presence of fog.