Preformed Cooper Pairs in Layered FeSe-Based Superconductors.

Superconductivity arises from two distinct quantum phenomena: electron pairing and long-range phase coherence. In conventional superconductors, the two quantum phenomena generally take place simultaneously, while in the underdoped high- T_{c} cuprate superconductors, the electron pairing occurs at higher temperature than the long-range phase coherence. Recently, whether electron pairing is also prior to long-range phase coherence in single-layer FeSe film on SrTiO_{3} substrate is under debate. Here, by measuring Knight shift and nuclear spin-lattice relaxation rate, we unambiguously reveal a pseudogap behavior below T_{p}∼60 K in two kinds of layered FeSe-based superconductors with quasi2D nature. In the pseudogap regime, a weak diamagnetic signal and a remarkable Nernst effect are also observed, which indicates that the observed pseudogap behavior is related to superconducting fluctuations. These works confirm that strong phase fluctuation is an important character in the 2D iron-based superconductors as widely observed in high-T_{c} cuprate superconductors.

High density lipoprotein (HDL) metabolism in noninsulin-dependent diabetes mellitus: measurement of HDL turnover using tritiated HDL.

High density lipoprotein (HDL) kinetics were studied by injecting [3H]apoprotein A-I (apoA-I)/HDL into 12 subjects with normal glucose tolerance and 12 patients with noninsulin-dependent diabetes mellitus (NIDDM). The results indicate that the mean fractional catabolic rate (FCR) of apoA-I/HDL was significantly faster [0.63 +/- 0.07 (+/- SEM) vs. 0.39 +/- 0.02 1/day; P less than 0.001] and the apoA-I/HDL synthetic rate greater (29.4 +/- 2.9 vs. 22.9 +/- 1.3 mg/kg X day; P less than 0.02) in patients with NIDDM than in normal subjects. Furthermore, there were statistically significant inverse relationships between apoA-I/HDL FCR and plasma levels of both HDL cholesterol (r = -0.71; P less than 0.001) and apoA-I (r = -0.63; P less than 0.001). In addition, the increase in apoA-I/HDL FCR was directly related to fasting plasma glucose (r = 0.78; P less than 0.001) and insulin (r = 0.76; P less than 0.001) concentrations. These data support the view that the decrease in plasma HDL cholesterol and apoA-I levels commonly found in patients with noninsulin-dependent diabetes is due to an increase in the catabolic rate of apoA-I/HDL secondary to the defects in carbohydrate metabolism present in these patients.

[Steroid diabetes: an analysis of 28 cases].

During a survey period of 28 years a total of 449 patients suffering respectively from pemphigus, systemic lupus erythematous and chronic nephritis was admitted to the hospital. Of the 286 patients who received glucocorticoid treatment 28 were found to have steroid diabetes (9.8%). The incidences of steroid diabetes in these diseases were as follows: pemphigus 20% (7/35), systemic lupus erythematous 12.5% (14/112), chronic nephritis 5% (7/139). Two thirds of the diabetic subjects appeared asymptomatic, while the remainder showed polydipsia and polyuria. Renal glucosuria was seen in 3 cases and hyperosmolar hyperglycemia in 4. Blood glucose level in 10 out of the 21 remaining cases was 8.9 +/- 1.5 mmol/L and in the other 11 cases 14.8 +/- 2.4 mmol/L. Generally, the treatment of steroid diabetes is not intricate. Satisfactory improvement was seen in about 80% of the patients if a strict line of therapy against primary diabetes was oriented. In this series 18 patients did well under the treatment either with reduction of steroid or with use of oral hypoglycemic agents or insulin or both. Their blood glucose levels returned to normal and urine sugar disappeared rapidly. Four of the 5 deaths were caused by their primary diseases. One died of pemphigus complicated with infection and shock exhibiting an ante mortem blood glucose level as high as 31.7 mmol/L, obviously hyperosmolar status being the predisposing factor. Due to the fact that most of the steroid diabetic patients were clinically asymptomatic, delayed or misbranded diagnosis was not infrequently seen.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of insulin therapy on abnormal bone and mineral metabolism in chronic streptozotocin-induced diabetic rat].

By use of histomorphometry and photon and physical, calcium homeostasis, bone morphology, bone mass and bone growth were studied in freely fed control, streptozotocin-induced diabetic, long-term and short-term insulin treated diabetic rats 14 weeks after the induction of diabetes. We conclude that untreated chronic streptozotocin-induced diabetic rat could result in abnormal bone and mineral metabolism, which is characterized by hypercalciuria, hyperphosphaturia and hyperphosphatemia, significant bone loss and growth arrest. The extent of bone loss correlated with the duration of the disease process. The anatomical basis of bone mass reduction is the diminution of osteoblasts activity which results in reduction of bone formation and insufficient bone calcification and relative increment of osteoclasts activity. Thus, bone resorption overweight bone formation leading to a negative balance of bone remodeling. The effect of PTH and CT on bone changes in diabetic rats can't be affirmed in our experiments. It is probable that metabolic disorder and/or insulin deficiency has a direct effect on bone changes. Insulin therapy started earlier in the course can prevent and somewhat later can completely normalize the altered skeletal morphology of diabetic rats. Whether this result is due to direct effect of insulin on skeletal tissue or through the correction of metabolic disorder remains to be resolved.

[A comparison between glibenclamide and glipizide in the treatment of type II diabetes].

This study enrolled 36 newly-diagnosed patients with NIDDM, who were divided into two groups, the glibenclamide group and the glipizide group. In each group there were 18 cases, and both group were equal in average age and duration, steam bread tolerance test, GHbA1 and 6 hematological targets were made in both groups before and after administration with glibenclamide or glipizide. The results were as follows: (1) The hypoglycemic effect of glibenclamide was slightly great than that of glipizide. (2) VWF decreased significantly after administration with glibenclamide for 4 months. But in glipizide, only the length of thrombosis formation in vitro was greatly shortened. Thus glibenclamide was better than glipizide, in postponing and reducing microangiopathy complication.

Effect of insulin deficiency on low density lipoprotein metabolism in rabbits.

These studies have been carried out in rabbits with alloxan-induced diabetes in order to see if insulin deficiency affects low density lipoprotein (LDL) catabolism. The results showed that plasma LDL-cholesterol was lower in diabetic rabbits, associated with a fall in the cholesterol to protein ratio of LDL particles. In addition, 125I-LDL disappeared more slowly from plasma of diabetic rabbits, leading to a significant reduction in fractional catabolic rate and a decrease in residence time of 125I-LDL. These data demonstrated that LDL composition and catabolism are greatly altered as a consequence of insulin deficiency.

Role of insulin in regulation of high density lipoprotein metabolism.

The effect of alloxan-induced insulin deficiency on high density lipoprotein (HDL) metabolism was studied in rabbits. Rabbits with alloxan-induced diabetes had significantly higher (P less than 0.001, mean +/- SEM) plasma concentrations of glucose (541 +/- 13 vs. 130 +/- 2 mg/dl), triglyceride (2851 +/- 332 vs. 101 +/- 10 mg/dl), and total plasma cholesterol (228 +/- 55 vs. 42 +/- 4 mg/dl) than did normal control rabbits. However, diabetic rabbits had lower plasma HDL-cholesterol (7.2 +/- 1 vs. 51.3 +/- 1.3 mg/dl, P less than 0.001) and HDL apoA-I (38.3 +/- 6.0 vs. 87.2 +/- 4.3 mg/dl, P less than 0.001) concentrations. HDL kinetics were compared in diabetic and normal rabbits, using either 125I-labeled HDL or HDL labeled with 125I-labeled apoA-I, and it was demonstrated that HDL fractional catabolic rate (FCR) was slower and residence time was longer in the diabetic rabbits when either tracer was used. The slow FCR and the low apoA-I pool size led to reduced apoA-I/HDL synthetic rate in diabetic rabbits (0.97 +/- 0.11 vs. 0.34 +/- 0.07 mg per kg per hr). Thus, the reduced plasma HDL-cholesterol concentrations seen in rabbits with alloxan-induced insulin deficiency was associated with a lower total apoA-I/HDL synthetic rate. Since insulin treatment restored to normal all of the changes in plasma lipoprotein concentration and kinetics seen in diabetic rabbits, it is unlikely that the phenomena observed were secondary to a nonspecific toxic effect of alloxan. These data strongly support the view that insulin plays an important role in regulation of HDL metabolism.