Fermi surface nesting induced strong pairing in iron-based superconductors.

The discovery of high-temperature superconductivity in iron pnictides raised the possibility of an unconventional superconducting mechanism in multiband materials. The observation of Fermi-surface (FS)-dependent nodeless superconducting gaps suggested that inter-FS interactions may play a crucial role in superconducting pairing. In the optimally hole-doped Ba(0.6)K(0.4)Fe(2)As(2), the pairing strength is enhanced simultaneously (2Delta/T(c) approximately 7) on the nearly nested FS pockets, i.e., the inner hole-like (alpha) FS and the 2 hybridized electron-like FSs, whereas the pairing remains weak (2Delta/T(c) approximately 3.6) in the poorly nested outer hole-like (beta) FS. Here, we report that in the electron-doped BaFe(1.85)Co(0.15)As(2), the FS nesting condition switches from the alpha to the beta FS due to the opposite size changes for hole- and electron-like FSs upon electron doping. The strong pairing strength (2Delta/T(c) approximately 6) is also found to switch to the nested beta FS, indicating an intimate connection between FS nesting and superconducting pairing, and strongly supporting the inter-FS pairing mechanism in the iron-based superconductors.

Low vitamin D status despite abundant sun exposure.

CONTEXT: Lack of sun exposure is widely accepted as the primary cause of epidemic low vitamin D status worldwide. However, some individuals with seemingly adequate UV exposure have been reported to have low serum 25-hydroxyvitamin D [25(OH)D] concentration, results that might have been confounded by imprecision of the assays used. OBJECTIVE: The aim was to document the 25(OH)D status of healthy individuals with habitually high sun exposure. SETTING: This study was conducted in a convenience sample of adults in Honolulu, Hawaii (latitude 21 degrees ). PARTICIPANTS: The study population consisted of 93 adults (30 women and 63 men) with a mean (sem) age and body mass index of 24.0 yr (0.7) and 23.6 kg/m(2) (0.4), respectively. Their self-reported sun exposure was 28.9 (1.5) h/wk, yielding a calculated sun exposure index of 11.1 (0.7). MAIN OUTCOME MEASURES: Serum 25(OH)D concentration was measured using a precise HPLC assay. Low vitamin D status was defined as a circulating 25(OH)D concentration less than 30 ng/ml. RESULTS: Mean serum 25(OH)D concentration was 31.6 ng/ml. Using a cutpoint of 30 ng/ml, 51% of this population had low vitamin D status. The highest 25(OH)D concentration was 62 ng/ml. CONCLUSIONS: These data suggest that variable responsiveness to UVB radiation is evident among individuals, causing some to have low vitamin D status despite abundant sun exposure. In addition, because the maximal 25(OH)D concentration produced by natural UV exposure appears to be approximately 60 ng/ml, it seems prudent to use this value as an upper limit when prescribing vitamin D supplementation.

Ceruletide inhibits phencyclidine-induced dopamine and serotonin release in rat prefrontal cortex.

Phencyclidine (PCP; 5.0 mg/kg, i.p.) produced a greater increase in extracellular dopamine (DA) levels in the prefrontal cortex than in the striatum, while PCP increased the extracellular 5-hydroxytryptamine (serotonin; 5-HT) levels in the prefrontal cortex but not the striatum, as determined by in vivo microdialysis in awake, freely moving rats. The cholecystokinin (CCK)-related decapeptide ceruletide (120 and 400 microg/kg, i.p.), administered 60 min prior to PCP, significantly attenuated the PCP-induced increase in the extracellular levels of DA and 5-HT in the prefrontal cortex, but not in the striatum. These effects were reversed by PD 135,158, a selective CCK-B receptor antagonist (0.1 mg/kg, s.c.), administered 5 min prior to ceruletide. When administered alone, ceruletide (400 microg/kg, i.p.) significantly increased basal extracellular DA levels only in the prefrontal cortex. The selective N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (0.5 mg/kg, i.p.) also increased extracellular DA levels in the prefrontal cortex, but this effect was unaffected by ceruletide pretreatment. These results suggest that ceruletide may differentially modulate basal and PCP-induced release of DA and 5-HT in the prefrontal cortex.

[Pre-operative autologous blood collection in neurosurgical patients].

Homologous transfusion has been known to cause viral infections and other complications. Recently, autologous transfusion has been adopted widely as a safer and more effective procedure to prevent these complications. The authors report the experiences of 29 patients who had been operated on after preparation of autologous blood. Furthermore, the authors report a study concerning maximum surgical blood order schedule (MSBOS) of these operations. 212 patients operated on between January, 1991 and June, 1993 were used for this study of MSBOS. Although intraoperative transfusion was performed on 14 of 29 patients, the need for homologous transfusion was avoided in 12 of these 14 patients by the use of autologous blood. The frequency of homologous transfusion was reduced significantly after the introduction of pre-operative autologous blood collection in our clinic. The patients' value of hemoglobin fell after the collection of blood but these levels were not so seriously low as to impede the performance of operations. 212 cases of operated patients were divided according to the operative methods and diagnosis for calculation of MSBOS. The results were as follows; Craniotomy and removal of glioma 5u, meningioma 11u, neurinoma 7u, AVM 5u, transsphenoidal surgery 3u, Moyamoya disease 2u and V-P or S-P shunt 0u. Pre-operative autologous blood collection is easy to achieve for scheduled neurosurgical operations, and autologous transfusion is a beneficial procedure which should be used more widely.

[A case of dermatomyositis associated with breast cancer].

Presented is a case of a 48-year-old woman with dermatomyositis associated with breast cancer. A standard radical mastectomy against the breast cancer was performed in addition to the administration of adriamycin, 5-Fu, and tamoxifen as adjuvant chemoendocrine therapy. The symptoms of dermatomyositis were not that severe, so no steroid therapy was given. The patient now is ambulatory and has been discharged, and no symptoms of recurrence or exacerbations of dermatomyositis has occurred.