Electron emission from 57Fe nuclei excited with synchrotron radiation

The increase in cytosolic free Ca2+ concentration ([Ca2+]i) seen in submandibular cells of early postnatal rats following exposure to acetylcholine (ACh) is larger than in cells of adult rats. To elucidate possible reasons for this difference, we compared Ca2+ movements through Ca2+ pumps in both types of cells using Ca(2+)-sensitive fluorescent probe fura-2 and the radiotracer 45Ca2+. Ca2+ release induced by endoplasmic reticulum (ER) Ca(2+)-pump inhibitor thapsigargin (TG) was significantly smaller in neonatal cells than in adult cells, whereas the inositol 1,4,5-trisphosphate (IP3)-elicited Ca2+ release was comparable in both cell types. This suggests that although the size of the IP3-sensitive Ca2+ pool is adequate in immature cells, the activity of TG-sensitive Ca2+ pump in this pool is lower. The activity of the plasma membrane (PM) Ca(2+)-pump, measured by extrusion of 45Ca2+, was also significantly lower in immature cells. These results indicate that both ER and PM Ca2+ pumps may be functionally underdeveloped in immature cells, and that the enhanced increase of [Ca2+]i seen in response to ACh in immature cells may be partially, if not completely, due to a reduced capacity for removal of Ca2+ from the cytosol by active mechanisms.     

Type II secretory phospholipase A2 associated with cell surfaces via C-terminal heparin-binding lysine residues augments stimulus-initiated delayed prostaglandin generation

Type II secretory phospholipase A2 (sPLA2) has been shown to be induced by a variety of proinflammatory stimuli and, therefore, has been implicated in the inflammatory process. In order to determine whether association of sPLA2 with cell surfaces via heparan sulfate proteoglycan is important for its effects on cellular functions, we have identified the critical domain in sPLA2 for heparin and cell surface binding and examined its role in cellular prostaglandin (PG) biosynthesis. Replacement of several conserved Lys residues in the C-terminal region of mouse and rat sPLA2s by Glu resulted in a marked reduction of their capacities to bind to heparin and mammalian cell surfaces without affecting their enzymatic activities toward dispersed phospholipid as a substrate. CHO cells stably transfected with wild-type sPLA2 released about twice as much arachidonic acid (AA) during culture for 10 h with fetal calf serum and interleukin-1beta than cells transfected with vector alone, whereas the ability to enhance AA release was impaired in sPLA2 mutants incapable of binding to cell surfaces. AA released by wild-type sPLA2-transfected CHO cells was metabolized to prostaglandin E2 via prostaglandin endoperoxide H synthase (PGHS)-2 after IL-1beta stimulation, revealing a particular functional linkage of sPLA2 to PGHS-2. In contrast, A23187-initiated immediate AA release over 30 min was not affected by sPLA2 overexpression. Taken together, these results suggest that sPLA2 expressed endogenously and anchored on cell surfaces via its C-terminal heparin-binding domain is involved in the PGHS-2-dependent delayed PG biosynthesis initiated by growth factors and cytokines during long term culture.     

Luminescence properties of Y_2WO_6:Yb~(3+)/Er~(3+) with enhanced red emission via upconversion

The Er~(3+)/Yb~(3+) co-doped Y2 WO6 phosphors were prepared via high temperature solid method for the first time. The structure was investigated with X-ray diffraction(XRD). The crystal morphology was observed through scanning electron microscopy(SEM). Under the excitation of 980 nm diode laser,visible up-conversion(UC) emissions were observed in green and red regions. The luminescence study reveals strong ~4 S_(3/2) to ~4 I_(15/2) transition at 545 nm and strong ~4 F_(9/2) to ~4 I_(15/2) transition at 657 nm. The relative intensities ratios of red(510-580 nm) to green(640-690 nm) emissions(R_(R/G)) reduce when the samples co-doped with Yb~(3+) ions. The dependence of emission intensity on the pump power indicate that visible UC emissions are governed by two photons, meanwhile three photons process is also involved. For more details, the discussion is made in the energy level diagrams.     

Use of 123I-BMIPP single-photon emission tomography to estimate areas at risk following successful revascularization in patients with acute myocardial infarction

PURPOSE: To determine the frequency and nature of intraoperative complications of endocapsular phacoemulsification cataract surgery. SETTING: Dalcross Private Hospital and the Departments of Ophthalmology, Concord Hospital and Prince of Wales Hospital, Sydney, Australia. METHODS: This prospective study included the first 1000 cases of planned endocapsular phacoemulsification cataract surgery performed by an experienced surgeon. A standardized proforma was completed at the time of surgery. Data recorded included pre-existing ocular abnormalities, duration of surgery, nuclear sclerosis grade, and intraoperative complications. RESULTS: Major complications comprised posterior capsule tears with vitreous loss (1.4%), isolated posterior capsule tears (0.7%), and zonulysis (0.1%). Minor complications included anterior capsule tears (3.8%), iris prolapse (0.6%), and ciliary body incision (0.2%). There was a significant trend toward complications as the nuclear sclerosis grade increased. The incidence of major complications was 9.3% in the first 150 cases and 0.9% in the last 850. This represents a relative risk of 9.9 (95% confidence interval 4.2 to 23.0) of a major complication occurring in the first 150 compared with the later 850 cases. CONCLUSION: The frequency of major and minor complications fell sharply after the first 150 operations and was maintained. This study may provide a guide for beginning phacoemulsification surgeons and a basis for experienced surgeons to compare their performance outcomes.     

Evaluation of the cardiac and pulmonary uptake of Thallium 201 in subject with suspected ischemic heart disease examined by single-photon emission tomography with Thallium 201, at rest and after exertion

Counts in selected lung and heart ROI were taken in 10 thallium-201 stress SPECT. They were tested for diseased or welfare status of the patient. Eighteen parameters from scintigraphies and from stress test for each patient were placed in a file and tested for correlation in a minicomputer. Lung/heart ratio was found to be not indicative of disease while it is a sign of thallium distribution in the body. Numerical evaluation of scintigraphies was however found to be a sign of disease.