Mapping scoping reviews in neurosurgery: a scoping review protocol.

INTRODUCTION: The realm of neurosurgery is currently witnessing a surge in primary research, underscoring the importance of adopting evidence-based approaches. Scoping reviews, as a type of evidence synthesis, offer a broad perspective and have become increasingly vital for managing the ever-expanding body of research in swiftly evolving fields. Recent research has indicated a rising prevalence of scoping reviews in healthcare literature. In this context, the concept of a 'review of scoping reviews' has emerged as a means to offer a higher level synthesis of insights. However, the field of neurosurgery appears to lack a comprehensive integration of scoping reviews. Therefore, the objective of this scoping review is to identify and evaluate the extent of scoping reviews within neurosurgery, pinpointing research gaps and methodological issues to enhance evidence-based practices in this dynamic discipline. METHODS: The method framework of Arksey and O'Malley will be used to conduct the scoping review. A thorough literature search will be performed on Medline, Scopus and Web of Science to find eligible studies using the keywords related to neurosurgery, scoping review and its variants. Two reviewers will independently revise all of the full-text articles, extract data and evaluate the study extent. A narrative overview of the findings from included studies will be given. ETHICS AND DISSEMINATION: This review will involve secondary analysis of published literature, and therefore ethics approval is not required. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist will be used to guide translation of findings. Results will be disseminated through peer-reviewed journals and presented in conferences via abstract and presentation.

Correction: Influence of alcohol provocation on medical professionals in Taiwan: A qualitative study.

[This corrects the article DOI: 10.1371/journal.pone.0264071.].

Collaborative clinical reasoning: a scoping review.

Background: Collaborative clinical reasoning (CCR) among healthcare professionals is crucial for maximizing clinical outcomes and patient safety. This scoping review explores CCR to address the gap in understanding its definition, structure, and implications. Methods: A scoping review was undertaken to examine CCR related studies in healthcare. Medline, PsychInfo, SciVerse Scopus, and Web of Science were searched. Inclusion criteria included full-text articles published between 2011 to 2020. Search terms included cooperative, collaborative, shared, team, collective, reasoning, problem solving, decision making, combined with clinical or medicine or medical, but excluded shared decision making. Results: A total of 24 articles were identified in the review. The review reveals a growing interest in CCR, with 14 articles emphasizing the decision-making process, five using Multidisciplinary Team-Metric for the Observation of Decision Making (MDTs-MODe), three exploring CCR theory, and two focusing on the problem-solving process. Communication, trust, and team dynamics emerge as key influencers in healthcare decision-making. Notably, only two articles provide specific CCR definitions. Conclusions: While decision-making processes dominate CCR studies, a notable gap exists in defining and structuring CCR. Explicit theoretical frameworks, such as those proposed by Blondon et al. and Kiesewetter et al., are crucial for advancing research and understanding CCR dynamics within collaborative teams. This scoping review provides a comprehensive overview of CCR research, revealing a growing interest and diversity in the field. The review emphasizes the need for explicit theoretical frameworks, citing Blondon et al. and Kiesewetter et al. The broader landscape of interprofessional collaboration and clinical reasoning requires exploration.

Energy and Infrared Radiation Characteristics of the Sandstone Damage Evolution Process.

The mechanical characteristics and mechanisms of rock failure involve complex rock mass mechanics problems involving parameters such as energy concentration, storage, dissipation, and release. Therefore, it is important to select appropriate monitoring technologies to carry out relevant research. Fortunately, infrared thermal imaging monitoring technology has obvious advantages in the experimental study of rock failure processes and energy dissipation and release characteristics under load damage. Therefore, it is necessary to establish the theoretical relationship between the strain energy and infrared radiation information of sandstone and to reveal its fracture energy dissipation and disaster mechanism. In this study, an MTS electro-hydraulic servo press was used to carry out uniaxial loading experiments on sandstone. The characteristics of dissipated energy, elastic energy, and infrared radiation during the damage process of sandstone were studied using infrared thermal imaging technology. The results show that (1) the transition of sandstone loading from one stable state to another occurs in the form of an abrupt change. This sudden change is characterized by the simultaneous occurrence of elastic energy release, dissipative energy surging, and infrared radiation count (IRC) surging, and it has the characteristics of a short duration and large amplitude variation. (2) With the increase in the elastic energy variation, the surge in the IRC of sandstone samples presents three different development stages, namely fluctuation (stage Ⅰ), steady rise (stage Ⅱ), and rapid rise (stage Ⅲ). (3) The more obvious the surge in the IRC, the greater the degree of local damage of the sandstone and the greater the range of the corresponding elastic energy change (or dissipation energy change). (4) A method of sandstone microcrack location and propagation pattern recognition based on infrared thermal imaging technology is proposed. This method can dynamically generate the distribution nephograph of tension-shear microcracks of the bearing rock and accurately evaluate the real-time process of rock damage evolution. Finally, this study can provide a theoretical basis for rock stability, safety monitoring, and early warning.

Medical Dispute Cases Caused by Errors in Clinical Reasoning: An Investigation and Analysis.

Studies that examine medical dispute cases (MDC) due to clinical reasoning (CR) are scarce in Taiwan. A retrospective analysis was undertaken to review MDC filed at four hospitals in Taiwan between 2011 and 2015. Cases were examined for the healthcare professionals involved, their relevance to CR errors, clinical specialties, and seniority. Seventy-eight MDC were identified and 57.7% of which were determined to be related to CR errors (n = 45). Among the 45 cases associated with CR errors, 82.2% (37) and 22.2% (10) were knowledge- and skill-related errors, respectively. The healthcare professionals with the most MDC were obstetrician-gynecologists (10/90, 11.1%), surgeons (8/90, 8.9%), and emergency physicians (7/90, 7.8%). The seniority of less than 5 years or lower had the highest number of attending physicians to be associated with MDC. In contrast, the highest seniority (>25 years) in the physician group and year 6 in the resident group are both shown with zero MDC. In our study, the larger hospitals had a significantly higher incidence of MDC compared to the smaller hospitals (Pearson Correlation Coefficient = 0.984, p = 0.016). An examination of MDC reveals the frequency and nature of medical errors in Taiwanese hospitals. Having identified that CR errors contributed a substantial fraction to the overall MDC, strategies to promote reasoning skills and hence reduce medico-legal issues help safeguard both patients and healthcare professionals.

Influence of alcohol provocation on medical professionals in Taiwan: A qualitative study.

There is a paucity of research on the issue of alcohol provocation in the medical field. While studies have been performed concerning alcohol abuse among students, no studies have concentrated on alcohol provocation among medical professionals. Therefore, it is essential to look at the underlying factors that may influence alcohol use by medical professionals. A qualitative study using focus groups was conducted to construct themes depicting medical professionals' experiences of alcohol provocation. Physicians (n = 32) and residents (n = 29) were recruited from a large teaching hospital in Taiwan. The volunteers included both subjects and instigators of alcohol provocation (individuals being pressured to drink and those who exert such pressure on others). A questionnaire on their alcohol use was used to quantitatively assess the prevalence of alcohol consumption and inebriation. The participants were then interviewed separately in groups. All interview data were recorded, transcribed and analysed thematically. A notable prevalence of recent alcohol consumption was observed in both the physicians (n = 18, 56%) and residents (n = 17, 59%). Three prominent themes were identified and summarized: (1) Social drinking in the Taiwanese medical profession (2) Workplace hierarchy and changes in drinking culture, and (3) Influence on the medical profession. The behaviour of alcohol provocation among these medical professionals was revealed with its underlying factors of specific cultural norms, workplace hierarchy and social expectations. An understanding of alcohol provocation helps increase the awareness of adverse consequences associated with alcohol provocation, encourage medical professionals to avoid inappropriate drinking behaviors, and reduce the risk of compromising medical professionalism.

A scoping review of clinical reasoning research with Asian healthcare professionals.

Clinical reasoning is the thought process that guides practice. Although a plethora of clinical reasoning studies in healthcare professionals exists, the majority appear to originate from Western cultures. A scoping review was undertaken to examine clinical reasoning related research across Asian cultures. PubMed, SciVerse Scopus, Web of Science and Airiti Library databases were searched. Inclusion criteria included full-text articles published in Asian countries (2007 to 2019). Search terms included clinical reasoning, thinking process, differential diagnosis, decision making, problem-based learning, critical thinking, healthcare profession, institution, medical students and nursing students. After applying exclusion criteria, n = 240 were included in the review. The number of publications increased in 2012 (from 5%, n = 13 in 2011 to 9%, n = 22) with a steady increase onwards to 12% (n = 29) in 2016. South Korea published the most articles (19%, n = 46) followed by Iran (17%, n = 41). Nurse Education Today published 11% of the articles (n = 26), followed by BMC Medical Education (5%, n = 13). Nursing and Medical students account for the largest population groups studied. Analysis of the articles resulted in seven themes: Evaluation of existing courses (30%, n = 73) being the most frequently identified theme. Only seven comparative articles showed cultural implications, but none provided direct evidence of the impact of culture on clinical reasoning. We illuminate the potential necessity of further research in clinical reasoning, specifically with a focus on how clinical reasoning is affected by national culture. A better understanding of current clinical reasoning research in Asian cultures may assist curricula developers in establishing a culturally appropriate learning environment.

Dry Eye: The Effect of Chi-Ju-Di-Huang-Wan Plus Si Wu Tang and the Underlying Mechanism.

Objectives: In this pilot study, the effect of 970 mg Chi-Ju-Di-Huang-Wan (CJDHW) plus 30 mg four-substance decoction (Si Wu Tang; CJDHWSWT) was evaluated, in terms of its ability to alleviate dry eye symptoms and its therapeutic mechanism. Methods: This double-masked prospective investigation has recruited dry eye patients who have been randomly selected into two groups, namely treatment (n = 15) versus nontreatment (n = 15). In the treatment group, a daily oral intake of CJDHWSWT plus eye drops systane ultra was given for 90 consecutive days. In the nontreatment group, only defined eye drops were prescribed. The examinations included Schirmer's test, fluorescein-stained superficial punctate keratitis (SPK), artificial tear consumption, tear vascular endothelium growth factor (VEGF) level, and ocular surface disease index. The drug safety tests included liver and kidney functions, and complete blood counts. The candidates were observed during the screening visit and the following three monthly follow-ups. The data were analyzed by unpaired Student's t-test. Results: Compared to no significance in the nontreatment group, CJDHWSWT significantly (p = 0.03) increased the tear secretion after 3 months of intake. Furthermore, in contrast to no significance in the treatment group, there were significant alterations, including (i) increased fluorescein-stained SPK areas (p = 0.03); (ii) increased artificial tear instillation amount (p = 0.03); (iii) elevated tear VEGF protein levels (p = 0.03) in the nontreatment group; and (iv) significant improvement in clinically relevant phenomenon (e.g., reading limit and uncomfortable feeling in windy conditions), after treatment of artificial tear plus oral intake of CJDHWSWT. As shown by the post-treatment normal defined laboratory data, there were no adverse drug effects. Conclusions: This study has supported that CJDHWSWT is safe and effective in relieving dry eye's clinically relevant symptoms/phenomena. CJDHWSWT avoided the tear VEGF upregulation probably induced by dry eye-associated hypoxia/ischemia.

A Scoping Review of Medical Education Research in Neurosurgery.

BACKGROUND: Little is known about the state of medical education (ME) research in neurosurgery. As ME started to develop in neurosurgery in recent years, it is important to understand the current status and develop the theory for advancement in neurosurgery. The aim of this study was to undertake a scoping review of neurosurgery literature on ME research. METHODS: MEDLINE, SCOPUS, and PubMed databases were searched. Inclusion criteria were full-text articles in English published from January 2006 to December 2017. Research aspects included country of publication, annual number of publications, journal types, type of participants, frequently researched topics, and research design. Search terms included neurosurgery, medical education, teaching, training, learning, and curriculum. RESULTS: A total of 9863 references were found across 3 databases. After duplicate removal and further screening, 533 references remained for coding analysis. ME research activity in neurosurgery is increasing and commonly observed in Western countries. Identified articles were mostly quantitative, with curriculum, assessment (especially simulation), and teaching and learning being the most dominant research themes. CONCLUSIONS: This study highlights the need for enhanced quantity and quality of ME research in neurosurgery. It identifies areas of highest priority and aspects to be improved and provides us with a rationale for future development in ME in neurosurgery. These findings reveal future education research direction and programmatic research areas, while also establishing a benchmark to assess changes in educational scholarship over time.

Dendrobium nobile Lindley and its bibenzyl component moscatilin are able to protect retinal cells from ischemia/hypoxia by dowregulating placental growth factor and upregulating Norrie disease protein.

BACKGROUND: Presumably, progression of developmental retinal vascular disorders is mainly driven by persistent ischemia/hypoxia. An investigation into vision-threatening retinal ischemia remains important. Our aim was to evaluate, in relation to retinal ischemia, protective effects and mechanisms of Dendrobium nobile Lindley (DNL) and its bibenzyl component moscatilin. The therapeutic mechanisms included evaluations of levels of placental growth factor (PLGF) and Norrie disease protein (NDP). METHODS: An oxygen glucose deprivation (OGD) model involved cells cultured in DMEM containing 1% O2, 94% N2 and 0 g/L glucose. High intraocular pressure (HIOP)-induced retinal ischemia was created by increasing IOP to 120 mmHg for 60 min in Wistar rats. The methods included electroretinogram (ERG), histopathology, MTT assay and biochemistry. RESULTS: When compared with cells cultured in DMEM containing DMSO (DMSO+DMEM), cells subjected to OGD and pre-administrated with DMSO (DMSO+OGD) showed a significant reduction in the cell viability and NDP expression. Moreover, cells that received OGD and 1 h pre-administration of 0.1 µM moscatilin (Pre-OGD Mos 0.1 µM) showed a significant counteraction of the OGD-induced decreased cell viability. Furthermore, compared with the DMSO+OGD group (44.54 ± 3.15%), there was significant elevated NDP levels in the Pre-OGD Mos 0.1 µM group (108.38 ± 29.33%). Additionally, there were significant ischemic alterations, namely reduced ERG b-wave, less numerous retinal ganglion cells, decreased inner retinal thickness, and reduced/enhanced amacrine's ChAT/Müller's GFAP or vimentin immunolabelings. Moreover, there were significantly increased protein levels of HIF-1α, VEGF, PKM2, RBP2 and, particularly, PLGF (pg/ml; Sham vs. Vehicle: 15.11 ± 1.58 vs. 39.53 ± 5.25). These ischemic effects were significantly altered when 1.0 g/Kg/day DNL (DNL1.0 + I/R or I/R+ DNL1.0) was applied before and/or after ischemia, but not vehicle (Vehicle+I/R). Of novelty and significance, the DNL1.0 action mechanism appears to be similar to that of the anti-PLGF Eylea [PLGF (pg/ml); DNL1.0 vs. Eylea+I/R: 19.93 ± 2.24 vs. 6.44 ± 0.60]. CONCLUSIONS: DNL and moscatilin are able to protect against retinal ischemic/hypoxic changes respectively by downregulating PLGF and upregulating NDP. Progression of developmental retinal vascular disorders such as Norrie disease due to persistent ischemia/hypoxia might be thus prevented.

Baicalein protects against retinal ischemia by antioxidation, antiapoptosis, downregulation of HIF-1α, VEGF, and MMP-9 and upregulation of HO-1.

PURPOSE: Retinal ischemia-associated ocular disorders are vision threatening. This study examined whether the flavonoid baicalein is able to protect against retinal ischemia/reperfusion. METHODS: Using rats, the intraocular pressure was raised to 120 mmHg for 60 min to induce retinal ischemia. In vitro, an ischemic-like insult, namely oxidative stress, was established by incubating dissociated retinal cells with 100 µM ascorbate and 5 µM FeSO4 (iron) for 1 h. The rats or the dissociated cells had been pretreated with baicalein (in vivo: 0.05 or 0.5 nmol; in vitro: 100 µM), vehicle (1% ethanol), or trolox (in vivo: 5 nmol; in vitro: 100 µM or 1 mM). The effects of these treatments on the retina or the retinal cells were evaluated by electrophysiology, immunohistochemistry, terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL) staining, Western blotting, or in vitro dichlorofluorescein assay. In addition, real-time-polymerase chain reaction was used to assess the retinal expression of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-9 (MMP-9), vascular endothelium growth factor (VEGF), and heme oxygenase-1 (HO-1). RESULTS: The retinal changes after ischemia included a decrease in the electroretinogram b-wave amplitude, a loss of choline acetyltransferase immunolabeling amacrine cell bodies/neuronal processes, an increase in vimentin immunoreactivity, which is a marker for Müller cells, an increase in apoptotic cells in the retinal ganglion cell layer linked to a decrease in the Bcl-2 protein, and changes in the mRNA levels of HIF-1α, VEGF, MMP-9, and HO-1. Of clinical importance, the ischemic detrimental effects were concentration dependently and/or significantly (0.05 nmol and/or 0.5 nmol) altered when baicalein was applied 15 min before retinal ischemia. Most of all, 0.5 nmol baicalein significantly reduced the upregulation of MMP-9; in contrast, 5 nmol trolox only had a weak attenuating effect. In dissociated retinal cells subjected to ascorbate/iron, there was an increase in the levels of reactive oxygen species, which had been significantly attenuated by 100 µM baicalein and trolox (100 µM or 1 mM; a stronger antioxidative effect at 1 mM). CONCLUSIONS: Baicalein would seem to protect against retinal ischemia via antioxidation, antiapoptosis, upregulation of HO-1, and downregulation of HIF-1α, VEGF, and MMP-9. The antioxidative effect of baicalein would appear to play a minor role in downregulation of MMP-9.

Resveratrol mitigates rat retinal ischemic injury: the roles of matrix metalloproteinase-9, inducible nitric oxide, and heme oxygenase-1.

PURPOSE: Retinal ischemia-associated ocular disorders, such as retinal occlusive disorders, neovascular age-related macular degeneration, proliferative diabetic retinopathy, and glaucoma are vision-threatening. In this study, we examined whether and by what mechanisms resveratrol, a polyphenol found in red wine, is able to protect against retinal ischemia/reperfusion injury. METHODS: In vivo rat retinal ischemia was induced by high intraocular pressure (HIOP), namely, 120 mmHg for 60 min. The mechanism and management was evaluated by electroretinogram (ERG) b-wave amplitudes measurement, immunohistochemistry, and real-time polymerase chain reaction. RESULTS: The HIOP-induced retinal ischemic changes were characterized by a decrease in ERG b-wave amplitudes, a loss of choline acetyltransferase immunolabeling of amacrine cell bodies/neuronal processes, and increased vimentin immunoreactivity, which is a marker of Müller cells, together with upregulation of matrix metalloproteinase-9 (MMP-9), heme oxygenase-1 (HO-1), and inducible nitric oxide (iNOS), and downregulation of Thy-1, both at the mRNA level. The detrimental effects due to the ischemia were concentration-dependent (weaker effect at 0.05 nmole) and/or significantly (at 0.5 nmole) altered when resveratrol was applied 15 min before or after retina ischemia. CONCLUSION: This study supports the hypothesis that resveratrol may be able to protect the retina against ischemia by downregulation of MMP-9 and iNOS, and upregulation of HO-1.

Embolus-induced branch retinal artery occlusion with a presenting best-corrected visual acuity of <6/12 and visual field defect: yag embolectomy safely restores arteriolar perfusion and/or visual function.

PURPOSE: To study the effects of translumenal Nd:YAG embolectomy (TYE) on the visual functions of patients presenting with decreased vision (<6/12) and visual field defect (VFD) from embolus-induced branch retinal artery occlusions. METHODS: Case reports. RESULTS: The initial information available for five Chinese patients consisted of best-corrected visual acuity, visual field, and the branch retinal artery embolus location/laterality. These consisted of Case 1 (6/15; 3-day upper VFD; temporal lower first bifurcation; left eye), Case 2 (6/120; 1-week upper VFD; macular edema; disk; right eye), Case 3 (6/30; 1-week upper VFD; temporal lower first bifurcation; left eye), Case 4 (6/60; 1-day lower VFD; temporal upper first bifurcation; left eye), and Case 5 (counting finger; temporal upper first bifurcation; left eye). In all five cases, a fluorescein angiogram showed delayed arteriolar filling. At approximately 2 weeks after a single TYE treatment (Cases 1, 3, and 5) or a double TYE treatment (Case 4), fluorescein angiogram showed restoration of arteriolar perfusion. Furthermore, the patients' visual field and MP-1 sensitivity reductions were attenuated in Cases 1, 3 and 4, and their best-corrected visual acuities had improved to 6/10 (Case 1), 6/7.5 (Case 3), 6/6 (Case 4), and 6/60 (Case 5). In Case 2, 2 TYE treatments combined with Avastin and Kenacort also improved her situation despite persistent macular edema with the best-corrected visual acuity further increasing to 6/7.5. CONCLUSION: Conclusively, TYE is a safe and effective procedure that can be used to treat eyes with embolus-induced branch retinal artery occlusion with a presenting best-corrected visual acuity of <6/12 and visual defect.

The effects and underlying mechanisms of S-allyl l-cysteine treatment of the retina after ischemia/reperfusion.

PURPOSE: Retinal ischemia-associated ocular disorders are vision-threatening. The aim of the present study was to examine whether S-allyl l-cysteine (SAC) is able to protect against retina ischemia/reperfusion injury. METHODS: In vivo, retinal ischemia in the rat was induced by raising intraocular pressure (IOP) to 120 mmHg for 60 min. In vitro, an ischemic-like insult, namely oxidative stress, was established by incubating retinal ganglion cell-5 (RGC-5) with 500 µM H(2)O(2) for 24 h. The mechanisms involved in these processes were evaluated by electrophysiology, immunohistochemistry, and molecular biological approaches. RESULTS: The retinal changes caused by the high IOP were characterized by a decrease in electroretinogram b-wave amplitudes, a loss of choline acetyltransferase immunolabeling amacrine cell bodies/neuronal processes, and an upregulation of the mRNA levels of hypoxia-inducible factor-1α (HIF-1α), vascular endothelium growth factor (VEGF), and matrix metalloproteinase-9 (MMP-9). The increased protein levels of HIF-1α, VEGF, and MMP-9 were also seen in RGC-5 cells subjected to defined oxidative stress. Of clinical importance, the ischemic/ischemic-like detrimental effects were concentration-dependently (least effect at 25 µM) and/or significantly (50 and/or 100 µM) blunted when SAC was applied 15 min before retinal ischemia or ischemic-like insult, respectively. CONCLUSION: SAC would seem to protect against retinal ischemia by acting as an antioxidant and inhibiting the upregulation of HIF-1α, VEGF, and MMP-9.

Baicalein significantly protects human retinal pigment epithelium cells against H2O2-induced oxidative stress by scavenging reactive oxygen species and downregulating the expression of matrix metalloproteinase-9 and vascular endothelial growth factor.

PURPOSE: Age-related macular degeneration is a leading cause of blindness in the elderly. At a later stage, neovascular or exudative age-related macular degeneration can lead to severe central vision loss that is related to aging-associated cumulative oxidative stress of the human retinal pigment epithelium (hRPE) cells. Early prevention with antioxidants is mandatory. The aim of this study was to determine whether and how baicalein can act as an antioxidant. METHODS: The methods used included lactate dehydrogenase, 2',7'-dichloro-fluorescein diacetate, or enzyme-linked immunosorbent assay to measure cell viability, oxygen free radical levels, or the levels of vascular endothelial growth factor (VEGF)/matrix metalloproteinase-9 (MMP-9), respectively. RESULTS: H2O2 dose-dependently reduced the cell viability of hRPE cells. This negative effect was dose-dependently (with a lower effect at 20µM) and significantly counteracted by pretreatment with baicalein (50µM). Treatment with H2O2 significantly stimulated the formation of oxygen free radicals. This increase was dose-dependently and significantly blunted by baicalein. Further, treatment with a sublethal dose of H2O2 was associated with an upregulation in the levels of VEGF and MMP-9. The increases in these proteins were also dose-dependently (with a lower effect at 20µM) and significantly (50µM) blunted by pretreatment with baicalein. CONCLUSION: This study supports an antioxidative role for baicalein whereby it protects hRPE cells against H2O2-induced oxidative stress by downregulating the levels of VEGF and MMP-9, which are increased by H2O2.

Therapeutic effects and mechanisms of action of mannitol during H2O2-induced oxidative stress in human retinal pigment epithelium cells.

BACKGROUND: Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. At a later stage, neovascular or exudative AMD can lead to severe central vision loss that is related to aging-associated cumulative oxidative stress of the human retinal pigment epithelium (hRPE) and choroid capillary. Early prevention with antioxidants is mandatory. The aim of this study was to determine whether and how mannitol can act as an antioxidant. METHODS: The methods used included measurements of cell viability, oxygen free radical (OFR) levels, lipid peroxide (LP) levels, and OFR-related enzyme protein levels. RESULTS: H(2)O(2) dose-dependently reduced the cell viability of hRPE cells. This negative effect was significantly counteracted by pretreatment with mannitol (1 mM). H(2)O(2) significantly stimulated the formation of OFR and LP. These increases were dose-dependently and significantly blunted by mannitol. Furthermore, treatment with H(2)O(2) was associated with a reduction in the level of catalase, but not of manganese superoxide dismutase (MnSOD). In contrast, it was shown that mannitol protected hRPE cells against the H(2)O(2)-induced oxidative stress by increasing the level of catalase, but not the level of MnSOD. CONCLUSION: This study supports an antioxidative role for mannitol that acts through up-regulating the level of catalase, which is decreased by H(2)O(2).

Series of metal-nonmetal-metal sandwich compounds: out-of-plane sigma-aromaticity and electric properties.

A new class of metal-nonmetal-metal sandwich structures M3-CO3-M3' (M, M' = Li, Na, K) with all real frequencies is obtained at the second-order Möller-Plesset theory (MP2) method with the 6-311+G (2d) basis set. Because the sandwich molecule M3-CO3-M3' is composed of superatoms (M3, CO3, and M3'), it is a sandwich "superomolecule". The superatoms M3 and M3' are electron donors and CO3 is the acceptor, and then there is a strong charge transfer between M3 (or M3') and CO3 superatom, so M3-CO3-M3' can be denoted as M3(+)CO3(2-)M3'(+). Owing to the CO3(2-) anion in the middle repulsing the valence electrons of two metal rings (M3 and M3') forming a pair of excess electrons, the compound with excess electrons is also a novel electride. In metal-nonmetal-metal sandwich compound M3(+)CO3(2-)M3'(+), superatom units M3(+) and M3'(+) exhibit unusual sigma-aromaticity: the maximum negative nucleus-independent chemical shift (NICSmax) value of each aromatic ring (M3(+) and M3'(+)) does not locate at the center of the ring plane but locates outside the ring plane. The distance value from the center of the M3(+) or M3'(+) ring plane to the point with NICSmax ranges from 0.8 to 1.9 A. This shows a notable out-of-plane sigma-aromaticity for these sandwich compounds. What is the reason? We find that the out-of-plane sigma-aromaticity of M3(+) (or M3'(+)) results from the action of CO3(2-)M3'(+) (or M3(+)CO3(2-)). For electric property, on account of excess electrons, the sandwich electride M3-CO3-M3' without the central symmetry can exhibit large static first hyperpolarizability (beta0). For Na3-CO3-K3, the beta0 value is close to 56,000 au.