PZ Concentration Research Articles

Dielectric Properties of Solid Solutions (1-x)Pb(In1/2Nb1/2)O3-xPbZrO3

Dielectric properties of (1- x)Pb(In1/2Nb1/2)O3 (PIN)- xPbZrO3 (PZ) were investigated. For PZ concentrations x<0.3, diffuse phase transition was observed. With increasing x, maximum permittivity ε′ rm increased, and the temperature T m at which ε′ rm appeared shifted towards higher temperatures. For x>0.3, ε r′ had a sharp peak at T c. With increasing x, the peak value decreased and T c shifted toward higher temperatures. The phase below T c was confirmed to be ferroelectric by observation of P-E hysteresis loops. The phase transformation from the relaxor to ferroelectric state occurred at x=0.3. For x>0.8, a steplike anomaly appeared at T t below T c. With increasing x, this anomaly became larger, and T t shifted toward higher temperatures. The phase below T t was confirmed to be antiferroelectric by observation of P-E double hysteresis loops. There was a structural change characterized by the splitting of the structure-sensitive maximum of (200) reflection of XRD patterns, similar to orthorhomic PZ, around x=0.8. Two morphotropic phase boundaries were found; one between pseudocubic and rhombohedral phases with ε′ rm of 12000 at 100 kHz was at x=0.3, and the other between rhombohedral and orthorhombic phases was at x=0.8 at room temperature.

Skeletal muscle glucose disposal after re-feeding in the hyperthyroid rat

Experimental hyperthyroidism has been demonstrated to influence insulin-stimulated glucose utilization in isolated skeletal muscle preparations from fed or starved rats, with increased glycogen-glucose < 1 -phosphate cycling [ I ] and diversion of carbon from net glycogenesis (storage) to glycolysis (degradation) [2]. The present study investigated whether this effect of hyperthywidism is also observed in the intact animal under physiological conditions associated with hyperinsulinaemia and skeletal muscle glycogen deposition, namely refeeding after prolonged (48 h) starvation. Effects of experimental hyperthyroidism o n concentrations of fructose 2,6-bisphosphate [Fru( 2,6)P2], an allosteric activator of glycolysis, were also examined. Two representative hindlimb skeletal muscles: soleus (type 1, oxidative, working in the resting state) and gastrocnemius (type 2. mixed oxidative/ glycolytic. non-working in the resting state), were chosen for study. Comparison was made with changes in glycogen and Fru( 2,6)/’, concentrations in the heart, which is known to exhibit profound changes in contractile activity and metabolism in hyperthyroidism. Albino Wistar rats were either starved for 48 h or starved for 48 h and then refed chow (52% carbohydrate; 16%) protein: 2% lipid, w / ~ ) ud lihitirm, sampling after 2. 4, 6, X or 24 h of refeeding. One group o f rats was injected with triiodothyronine (100 d 6 mg/ 100 g body wt.). Glycogen and Fru( 2,6)P2 concentrations were measured in extracts of freeze-clamped muscles as described previously [4]. Basal (48 h starved) glycogen concentrations were significantly lower in the soleus than in the gastrocnemius, whereas Fru( 2,6)P, concentrations were higher in soleus (compare Figs. l a and lh) . Hyperthyroidism had no effect on basal (48 h starved) glycogen or Fru(2,6)Pz concentrations in either skeletal muscle (Figs. 1 a and 1 h). The initial rate of glycogen repletion was significantly higher in the soleus than in the gastrocnemius (compare Figs. I u and 1 h). This is likely to be related to the significantly lower basal glycogen concentration which is observed in the

Immunochemical investigations on the problem of the pregnancy zone protein. XII. Serum concentrations of pregnancy-associated alpha-2-glycoprotein in diabetic pregnancy.

The concentration in serum of the pregnancy zone protein (PZ), a high molecular pregnancy-associated alpha 2-glycoprotein, increases during pregnancy, when oral contraceptives are taken and under certain pathological conditions. PZ is probably part of a multifactorial immunological defence system which prevents the premature rejection of the fetus and placenta which together may be regarded as an allograft. Normally, the PZ serum concentration begins to rise during the 6th-12th week of pregnancy and reaches its peak at about the 24th week. The mean values then remain stable and afterwards diminish slightly toward the end of the pregnancy. In contrast, the mean values in mothers with insulin-dependent diabetes mellitus continue to rise. Excessively high serum PZ concentrations are significantly more frequent among pregnant diabetic patients, especially where there is also rhesus D antigen incompatibility. No correlation was found between excessively high values and the risk features used for the Priscilla White classification. A few patients with progressive proliferative retinopathy even had unusually low values.

Basic levels of the immuno suppressive serum protein PZ in women-influence of age, parity, gonadotrophins and estrogens.

The basic levels of the pregnancy zone protein (PZ) were measured by a radio-immunoassay, in 270 women of various age. All women were apparently healthy taking no drugs. Values were correlated to age, parity, gonadotrophins and estrogens. A significant age dependent increase was found for PZ while no influence could be attributed to the other factors studied. The present results emphasize that the age dependent variation of PZ concentration should be considered when clinical data of this protein are evaluated.