The effect of chemical stimulation of the brain on glucoregulation was studied in anaesthetized rats. Adrenaline, noradrenaline, acetylcholine, dopamine and carbachol (5 X 10(-8) mol/microliter saline) were injected directly into the third cerebral ventricle and changes in hepatic venous plasma glucose, immunoreactive glucagon and insulin concentrations were studied. The injection of adrenaline and carbachol into the third cerebral ventricle resulted in a marked hyperglycaemia associated with increased immunoreactive glucagon. Adrenaline-induced hyperglycaemia was not affected by bilateral adrenalectomy, while carbachol-induced hyperglycaemia was completely inhibited by adrenalectomy. The injection of somatostatin (1 X 10(-9) mol) with adrenaline into the third cerebral ventricle did not influence adrenaline-induced hyperglycaemia, while carbachol-induced hyperglycaemia was inhibited by co-administration with somatostatin. These results suggest that adrenergic and cholinergic neurons in the central nervous system may increase hepatic glucose output by different mechanism.
We quantitatively determined the relative contributions of hormonal factors and the nervous system to the total glucose response after stimulation of the cholinergic neurons in the central nervous system of fed rats. Hepatic venous plasma glucose, glucagon, insulin, epinephrine, and norepinephrine were measured during 120 min after injection of neostigmine (5 X 10(-8) mol) into the third cerebral ventricle in rats subjected to bilateral adrenodemedullation (ADMX) to prevent epinephrine secretion (observed insulin secretion), with and without intravenous infusion of somatostatin to prevent glucagon and insulin secretion. Injection of neostigmine in intact rats resulted in increases in glucose, glucagon, epinephrine, and norepinephrine. Comparison of glucose areas suggests that 22% of the hyperglycemic response is due to the glucagon effect, that 29% is due to the epinephrine effect, and that an unknown factor other than epinephrine or glucagon, which may include activation through direct neural innervation of the liver via alpha-adrenergic receptor, contributes 49%. The suppressive effect of epinephrine on insulin secretion, which is potentially stimulated by direct neural activation of the pancreas, contributes 18% of the net hyperglycemia.
Pyrethroid pesticides have relatively weak toxicity and have generally and widely been used not only as agricultural pesticides but also as household pesticides and insecticides. However, the toxicities of pyrethroids in humans due to their long‐term accumulation have not been elucidated sufficiently. On the other hand, pyrethroids have shown neuropathies in animal studies. Research has been made to eliminate or reduce high‐concentration pyrethroids that were contained in agricultural products. However, any sufficient study has not been performed to eliminate trace amounts or low concentrations of pyrethroid pesticides contained in drinking water.
Abstract Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J2-flow theory (J2F), and J2-Gotoh’s corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming processes. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-tube forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square tube reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.
Abstract A finite element formulation for large elasto‐plastic deformation of polycrystalline materials is proposed in incremental form. The effect of rotation of crystal axes besides usual element rotaion is taken into account. Some numerical considerations on polycrystalline plasticity (i.e. stress‐strain curves for several proportional loadings, effect of change of loading path on stress‐strain curve, subsequent yield loci for uniaxial and equi‐biaxial loadings and so forth) are given for the case of small deformation by using a plate model which consists of 121 square FCC crystals.
Changes in Cholinesterase Activity, Nerve Conduction Velocity, and Clinical Signs and Symptoms in Termite Control Operators Exposed to Chlorpyrifos: Masahiro Gotoh, etal. Asahi Rosai Hospital— We have surveyed periodical medical examinations for pest and termite control operators (n=64) exposed to chlorpyrifos and other organophosphate pesticides. Distribution of serum butyrylcholinesterase (BuChE) activities of all workers ranged 0.01‐1.18 (ApH). Serum BuChE activities in 6 workers in one termite control company were severely depressed and ranged from 0.01 to 0.21 ΔpH. Erythrocyte acetylcholinesterase (AChE) activities in 3 workers were lower than the normal range. Erythrocyte AChE activities and serum BuChE acitivities in chlorpyrifos sprayers were significantly correlated (r=0.720). In other clinical signs, blood urine nitrogen (BUN) in 4 workers and white blood cell (WBC) counts in 4 workers were abnormal. Sensory nerve conduction velocities in the sural nerve of all 6 workers were significantly reduced to 18.8‐26.6 m/s in the left leg and 19.2‐27.2 m/s in the right leg. In the results of ophthalmic examinations, accommodation time (both eyes) in 4 workers extended over the normal range and electroretinography (ERG) in 2 workers showed abnormal ERG including disappearance of oscillatory potential. Chlorpyrifos residue in blood in 4 operators whose serum BuChE activities ranged from 0.01 to 0.03 ApH were detected in the range 2‐8 ng/m 1. They had sprayed chlorpyrifos daily for 5 d before every blood sampling. It is suggested that serum BuChE activity and sensory nerve conduction velocity are sensitive indicators to evaluate the effects of chlorpyrifos exposure, and may be used effectively to monitor exposure and the effects of chlorpyrifos on health.
