Human thyroid adenyl cyclase-stimulating activity in immunoglobulin G of patients with Graves' disease

We have studied the characteristics of the stimulation of adenyl cyclase (AC) activity in human thyroid plasma membranes by thyroid-stimulating hormone (TSH) and by immunoglobulin G (IgG) from the sera of patients with Graves' disease. AC activity was measured as adenosine 3',5'-cyclic monophosphate (cAMP) generated by membranes in a 10 minute incubation. IgG from two patients with Graves' disease possessed particularly potent human thyroid AC-stimulating activity; the dose-response curves with these IgGs were essentially parallel to those obtained with TSH. As little as 30 mug of the IgG of one patient with Graves' disease or 8 muU of TSH caused significant AC stimulation. A Lineweaver-Burk plot of the data suggested similarity in the site of action of both TSH and human thyroid adenyl cyclase stimulator (HTACS) in Graves' IgG. Submaximal doses of HTACS and TSH had additive effects on AC stimulation, but a large dose of a Graves' IgG with potent AC stimulating activity did not enhance AC stimulation by a maximal dose of TSH. The effect of HTACS on AC was slower in onset and longer in duration than an equipotent dose of TSH. HTACS was detectable in IgGs of 9 of 15 untreated hyperthyroid Graves' disease patients; its concentration, however, did not correlate significantly with tests of thyroid function, nor with long-acting thyroid stimulator (LATS) activity. In another 11 treated patients with Graves' disease, selected for the presence of LATS, HTACS and LATS were significantly correlated. We observed no inhibition of LATS activity in a Graves' IgG chosen for such testing because of its high titer of HTACS and no detectable LATS. However, an inhibitor of HTACS was detected in 2 of 4 IgGs; one of these two IgGs also inhibited AC stimulation by TSH. Conclusions: 1) Some Graves' disease IgGs contain a human thyroid AC stimulator (HTACS), probably different from LATS. 2) HTACS may act via a common pathway with TSH; it differs from TSH, however, in having a slower onset and a greater effect during more prolonged incubation with plasma membranes. 3) There is also an inhibitor of HTACS activity in some Graves' disease IgGs.     

Inhibition of insulin degradation by nonsuppressible insulin-like activity

Nonsuppressible insulin-like activity, provided by three sources, was evaluated for its effect on the proteolytic degradation of insulin utilizing insulin protease obtained from rat liver homogenate as well as liver cell membranes. All three preparations of nonsuppressible insulin-like activity were found to be competitive inhibitors of insulin degradation. In addition human plasma was fractionated yielding an acetone precipitate which was found to have nonsuppressible insulin-like activity and to be a competitive inhibitor of insulin protease.     

An easily computable solution to a two-phase Stefan problem

We present some simple relations approximating the behavior of a phase changes process with constant initial and boundary temperatures. Their use is illustrated for the melting of N-Eicosene paraffin wax.     

Role of the hippocampus in blocking and conditioned inhibition of the rabbit's nictitating membrane response.

In Exp I, bilateral aspiration of the dorsal hippocampus produced a disruption of blocking of 30 New Zealand rabbits' nictitating membrane response in L. J. Kamin's (1968, 1969) 2-stage paradigm, but had no effect on the formation of a Pavlovian conditioned inhibitor in Exp II (27 Ss). Results of Exp I indicate that normal Ss and those with cortical lesions given conditioning to a light-plus-tone CS gave CRs to both light and tone during nonreinforced presentations of each (test phase). If, however, compound conditioning was preceded by tone acquisition, only the tone elicited a CR during testing; that is, blocking was observed. In Ss with hippocampal lesions, however, CRs were given to both light and tone during testing whether or not compound conditioning was preceded by tone acquisition. Data from Exp II show that Ss with hippocampal lesions could discriminate as well as normal Ss and those with cortical lesions between a light (CS+) and light plus tone (CS-). In addition, when the inhibitory tone was subsequently paired with the UCS in retardation testing, Ss in all 3 lesion conditions acquired the CR at the same rate. Thus, it appears that hippocampal lesions do not disrupt conditioned inhibition. Results are taken as support for the view that the hippocampus is responsible for "tuning out" stimuli that have no adaptive value to the organism. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teachers' perceptions of and reactions to misbehavior in traditional and open classrooms.

Compared teachers' disciplinary activities in traditional and open classrooms. Measures of teachers' discipline and criticism and children's misbehavior were derived from observations of 3 traditional and 3 open elementary school classrooms. The teachers' discipline and criticism scores were significantly higher (p     

Coping, locus of control, social support, and combat-related posttraumatic stress disorder: A prospective study.

We examined the relations between coping, locus of control, and social support and combat-related posttraumatic stress disorder (PTSD). The sample consisted of 262 Israeli soldiers who suffered a combat stress reaction episode during the 1982 Lebanon war and were followed 2 and 3 years after their participation in combat. Cross-sectional analyses revealed significant relations between locus of control, coping, and social support and PTSD at the two points of assessment. Changes in PTSD from Time 1 to Time 2 were also associated with changes in coping. We discuss theoretical and methodological implications of the findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Epitaxial GaP by a semi-sealed dip process for high efficiency red LED's

A semi-sealed dip process has been used to grow Zn-O doped GaP layers for high efficiency red LED's. A close fitting floating quartz plug is used to prevent volatilization of Zn, Ga₂O, and GaP during saturation. Double epitaxial layers with efficiencies as high as 8. 0% have been grown by this process.     

A mild,protective and efficient procedure for grinding coal: cryocrushing

Conventional grinding methods are harsh and produce dramatic changes in coal. When coal, initially at room temperature, is ground in the presence of air, the high localized temperatures produced are known to cause both the production of gases and surface oxidation. These perturbations make meaningful measurements on the product very difficult. A technique that minimizes these effects is the pulverization of coal in liquid nitrogen. Compared with conventional methods, the process is rapid and appears to be less destructive chemically. Electron Spectroscopy for Chemical Analysis (ESCA) measurements support this conclusion. Surface oxidation is significantly reduced by this mild treatment. The method produces more particles below 38 μm than does conventional grinding and these fine particles are less prone to agglomeration.