Cyclin F Is Degraded during G2-M by Mechanisms Fundamentally Different from Other Cyclins

Cyclin F, a cyclin that can form SCF complexes and bind to cyclin B, oscillates in the cell cycle with a pattern similar to cyclin A and cyclin B. Ectopic expression of cyclin F arrests the cell cycle in G2/M. How the level of cyclin F is regulated during the cell cycle is completely obscure. Here we show that, similar to cyclin A, cyclin F is degraded when the spindle assembly checkpoint is activated and accumulates when the DNA damage checkpoint is activated. Cyclin F is a very unstable protein throughout much of the cell cycle. Unlike other cyclins, degradation of cyclin F is independent of ubiquitination and proteasome-mediated pathways. Interestingly, proteolysis of cyclin F is likely to involve metalloproteases. Rapid destruction of cyclin F does not require the N-terminal F-box motif but requires the COOH-terminal PEST sequences. The PEST region alone is sufficient to interfere with the degradation of cyclin F and confer instability when fused to cyclin A. These data show that although cyclin F is degraded at similar time as the mitotic cyclins, the underlying mechanisms are entirely distinct

Osteoprotective effects of Fructus Ligustri Lucidi aqueous extract in aged ovariectomized rats

<p>Abstract</p> <p>Background</p> <p><it>Fructus Ligustri Lucidi </it>(FLL) is a commonly used herb for treating bone disorders in Chinese medicine. The present study investigates the anti-osteoporotic activity of FLL aqueous extract in the model of postmenopausal bone loss in aged ovariectomized (OVX) female rats.</p> <p>Methods</p> <p>After eight weeks of treatment of FLL or water, the lumbar spine was scanned by peripheral quantitative computed tomography (pQCT). Effects of FLL water extract on osteogenic and adipogenic differentiations in rat mesenchymal stem cells (MSCs) were assessed by biochemical methods and staining.</p> <p>Results</p> <p>FLL aqueous extract significantly inhibited bone mineral density (BMD) loss in total, trabecular and cortical bones without affecting body weight and uterus wet weight. FLL extract significantly promoted osteogenesis and suppressed adipogenesis in MSCs as indicated by the elevated alkaline phosphatase activity, calcium deposition levels and decreased adipocyte number in a dose-dependent manner without cytotoxic effects. Real-time PCR analysis revealed significant increase of osteoprotegerin (OPG)-to-receptor activator for nuclear factor-κB ligand (RANKL) mRNA, indicating a decrease in osteoclastogenesis.</p> <p>Conclusion</p> <p>The present study demonstrates the osteoprotective effects of FLL aqueous extract on aged OVX rats, stimulation of osteogenesis, inhibition of adipogenesis and osteoclastogenesis in MSCs.</p

Non-granulomatous Interstitial Nephritis in a Chinese Man with Sarcoidosis

Clinical renal involvement in sarcoidosis is rare and has not been previously reported in Chinese patients. We report a case of non-granulomatous interstitial nephritis that presented with acute renal failure in a Chinese man with underlying sarcoidosis. Use of prednisolone led to dramatic renal improvement and partial resolution of his asymptomatic lung parenchymal lesions. Unfortunately, the patient subsequently died of cryptococcal meningitis and episodes of nosocomial pneumonia. One should closely monitor a patient with a presumptive diagnosis of sarcoidosis after embarking on treatment since infections like tuberculosis may mimic or coexist with the disease. This is particularly important in areas where sarcoidosis is exceedingly rare

Vocational evaluation and vocational guidance for young people with a history of drug abuse

BACKGROUND: Young people recovering from drug addiction often face challenges in returning to the job market and in maintaining their jobs. Many of them feel they have no choice but to do entry-level work, and they are often unsure about their work ability and vocational choice. OBJECTIVE: In collaboration with a youth outreach service, this study aims to provide a package of vocational assessment, guidance, and support for these clients. METHODS: Using a strength-based case management framework, we conducted a comprehensive vocational evaluation for each participant (N=17), which covered self-perception of abilities, work and occupational interests, work readiness, work-related self-efficacy, and work aptitudes. We presented assessment results to each client and provided guidance on their education, training, or vocational choice. RESULTS: The results of aptitude tests indicate that most participants can cope with an entry-level job. Many participants are strong in jobs that require quick decision-making, sorting, assembly, and clerical tasks, but many are weak in fine manual dexterity and eye-hand-foot coordination. Many participants preferred jobs that are creative, indefinite, and autonomous in nature. CONCLUSION: Longer-term vocational counseling and coaching is needed to help clients make vocational choices and extend their job tenure. Many clients will also need training in job seeking and job maintenance skills.Youth Outreach Service, Salvation Army of Hong Kon

Chronic intermittent hypoxia induces local inflammation of the rat carotid body via functional upregulation of proinflammatory cytokine pathways

Maladaptive changes in the carotid body (CB) induced by chronic intermittent hypoxia (IH) account for the pathogenesis of cardiovascular morbidity in patients with sleep-disordered breathing. We postulated that the proinflammatory cytokines, namely interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α, and cytokine receptors (IL-1r1, gp130 and TNFr1) locally expressed in the rat CB play a pathophysiological role in IH-induced CB inflammation. Results showed increased levels of oxidative stress (serum 8-isoprostane and nitrotyrosine in the CB) in rats with 7-day IH treatment resembling recurrent apneic conditions when compared with the normoxic control. Local inflammation shown by the amount of ED1-containing cells (macrophage infiltration) and the gene transcripts of NADPH oxidase subunits (gp91phox and p22phox) and chemokines (MCP-1, CCR2, MIP-1α, MIP-1β and ICAM-1) in the CB were significantly more in the hypoxic group than in the control. In addition, the cytokines and receptors were expressed in the lobules of chemosensitive glomus cells containing tyrosine hydroxylase and the levels of expressions were significantly increased in the hypoxic group. Exogenous cytokines elevated the intracellular calcium ([Ca2+]i) response to acute hypoxia in the dissociated glomus cells. The effect of cytokines on the [Ca2+]i response was significantly greater in the hypoxic than in the normoxic group. Moreover, daily treatment of IH rats with anti-inflammatory drugs (dexamethasone or ibuprofen) attenuated the levels of oxidative stress, gp91phox expression and macrophage infiltration in the CB. Collectively, these results suggest that the upregulated expression of proinflammatory cytokine pathways could mediate the local inflammation and functional alteration of the CB under chronic IH conditions

Fabrication and characterization of carbon nanocomposite based field emission X-ray devices

Carbon nanotubes (CNTs) have been produced on silicon wafer by filtered cathodic vacuum arc technique using cobalt-containing graphite targets followed by thermal chemical vapor deposition. The Co-containing amorphous carbon (a-C:Co) composite films have various contents of Co as a catalyst for CNTs growth. It is found that dense and random CNTs were grown on the a-C:Co composite film deposited using a 2 at.% Cocontaining graphite target and nanoforest CNTs on the composite films using 5, 10 and 15 at.% Co-containing targets. The nanoforest CNTs using a 15 at.% Co-containing target have very good field emission properties with a low threshold field of 1.6 V/Am and a high and stable current density of 2.1 mA/cm2 at 3 V/Am, which may result from the smaller diameter of CNTs. It is found that the field emission properties of the CNTs are significantly affected by the diameter of CNTs rather than its orientation. An x-ray source was built in a diode configuration using the CNTs as its cold electron source showing good potential in x-ray radiography.RGM 17/0

Late stage crowding: evidence from crowding of illusory contour and Chinese character

Flanked objects are difficult to identify using peripheral vision. This is visual crowding. Crowding is the perceptual bottleneck for reading (Pelli et al., 2007) and object recognition (Pelli & Tillman, 2008). Theories for crowding had been suggested, but the underlying neural mechanism remained unclear. Some perceptual manipulations had been shown to break crowding, hinting the cortical locus of crowding. In the first part of the current study, we ask whether illusory contour formation survives crowding of illusion inducers. We measured the contrast thresholds for discriminating the rotation angle of a target Kanizsa inducer with and without flankers. When the other three Kanizsa inducers were rotated to misalign with the target, we observed strong crowding indicated through contrast threshold elevation. Interestingly, however, subjects were able to judge the shape (thin vs. fat) of the illusory Kanizsa square even when the individual inducers were flanked. Internal representation of the percept in the inducer-aligned condition was further studied through the classification image technique. Classification images indicated that illusory contours were formed and used in the perceptual decision task in both the non-flanked and flanked conditions. These findings suggest that crowding happens after illusory contour formation. In the second part, we ask if Chinese character orientation affects crowding. Fifty commonly used traditional Chinese characters were selected as stimuli. We measured the contrast threshold for identifying upright and inverted target surrounded by either upright or inverted flankers. At 5? eccentricity, we observed an interaction effect between target and flanker orientation on crowding: upright flankers produced a stronger crowding effect than inverted flankers for inverted but not upright target. Follow-up experiments showed that the observation was not due to a rise of detection sensitivity for upright flankers or a change of spatial extent between upright and inverted target. Yet, adding an enclosure to flankers eliminated the flanker orientation effect, suggesting that the flanker orientation effect may be attributed to the facilitation of texture perception in the periphery. At 10? eccentricity, upright target was generally more immune from crowding, further supporting that crowding takes place after Chinese character orientation has been coded. From previous fMRI studies, we know that lateral occipital complex (LOC) is the cortical site that first responds to Kanizsa?s illusory contours (Murray et al., 2002) and the fusiform gyrus is sensitive to the inversion of Chinese character (Kao, Chen, & Chen, 2009). Taken together with our findings, we infer that crowding happens at or after the two cortical locations.published_or_final_versionPsychologyMasterMaster of Philosoph

Crowding of Upright Chinese Character is Stronger with Inverted than Upright Flankers: An Exception of the Similarity Rule

Upright flanking faces have stronger detrimental effects on the recognition of upright target face, than inverted flanking faces. One possible explanation for this “flanker- inversion effect” was that the more holistically processed upright flanking faces allowed for more erroneous feature integration. Alternatively, crowding was known to be stronger when target and flankers were more similar. Here we investigate flanker-inversion effect on crowding in Chinese character identification. Five normally-sighted young adults participated. Targets of size 1.2° were presented at 5° in the lower visual field. Four flankers with center-to-center distance of 1.8° were presented in the crowded condition. Three types of flankers were used, upright or inverted Chinese and upright Korean characters. The identification contrast thresholds were estimated by QUEST and crowding strength was measured through threshold elevation (TE). Crowding on upright Chinese target was significantly stronger with inverted Chinese flankers (TE = 1.59±0.32) than with upright Chinese flankers (TE = 1.47±0.29). No inversion effect was observed for inverted Chinese target. Korean flankers produced similar crowding as upright Chinese flankers. Our results go against the similarity rule that predicts upright Chinese flankers would produce stronger crowding for upright Chinese target. Holistic processing preferred for inverted Chinese characters may account for the findings