Visible light induction of an electron paramagnetic resonance split signal in Photosystem II in the S(2) state reveals the importance of charges in the oxygen-evolving center during catalysis: a unifying model.

Cryogenic illumination of Photosystem II (PSII) can lead to the trapping of the metastable radical Y(Z)(•), the radical form of the redox-active tyrosine residue D1-Tyr161 (known as Y(Z)). Magnetic interaction between this radical and the CaMn(4) cluster of PSII gives rise to so-called split electron paramagnetic resonance (EPR) signals with characteristics that are dependent on the S state. We report here the observation and characterization of a split EPR signal that can be directly induced from PSII centers in the S(2) state through visible light illumination at 10 K.

Severe hypercalcemia in nonobstructive pyelonephritis with acute renal failure: hit or miss?

Severe hypercalcemia in the course of renal failure is quite unusual. If unrecognized, irreversible inexorable attrition of renal function takes place, carrying a substantial morbidity and mortality. In particular, acute nonobstructive pyelonephritis is barely considered in the primary differential diagnosis of renal failure.

Cognitive effects of calligraphy therapy for older people: a randomized controlled trial in Hong Kong.

Background: This pilot study investigated the effects of calligraphy therapy on cognitive function in older Hong Kong Chinese people with mild cognitive impairment.

Methods: A single-blind, randomized controlled trial was carried out in a sample of 31 adults aged 65 years or older with mild cognitive impairment. They were randomly assigned to receive either intensive calligraphy training led by a trained research assistant for eight weeks (calligraphy group, n = 14) or no calligraphy treatment (control group, n = 17).

Effectiveness of coordination exercise in improving cognitive function in older adults: a prospective study.

Background: Studies on the effect of a low intensity coordination exercise on the elderly with limited mobility are sparse. This prospective study attempted to compare the effectiveness of a customized coordination exercise and a strength exercise in improving the cognitive functioning and physical mobility on the elderly.

Methods: Participants from two centers for the elderly were allocated to practice either an 8-week coordination training (CT) program or an 8-week towel exercise (TE) program.

Surviving a crisis of HIV-associated immune reconstitution syndrome.

The management of life-threatening complications in HIV-associated immune reconstitution syndrome is becoming a challenging scenario in emergency practice, especially in the era of highly active antiretroviral therapy paralleled by increased worldwide incidence of HIV infection. Here, we described a 37-year-old woman with acute hypoxic respiratory failure, acute renal failure, and hypercalcemic crisis as the presenting features of HIV-associated immune reconstitution syndrome. In this patient, the restored granulomatous host response toward isolated pulmonary Mycobacterium avium complex infection led to a near-fatal catastrophe.

Nitrite-mediated S-nitrosylation of caspase-3 prevents hypoxia-induced endothelial barrier dysfunction.

Rationale: Hypoxia is a significant perturbation that exacerbates endothelial barrier dysfunction, contributing to the disruption of vascular homeostasis and the development of various diseases such as atherosclerosis and metastasis of tumors. To date, it is not known what strategy might be used to counter the effect of hypoxia on endothelial permeability.

Objective: This study investigated the role of nitrite in regulating vascular integrity under hypoxic conditions.

To accomplish preliminary Qigong simulation state by acupuncture.

Objective: The purpose of the study was to find out how to enter the preliminary Qigong simulation state in a short period of time.

Methods: This is a non-randomized, human experiment with healthy participants. A multi-channel digital physiological data recorder was used to detect whether the participants had entered the Qigong state.

Modeling Photosystem I with the alternative reaction center protein PsaB2 in the nitrogen fixing cyanobacterium Nostoc punctiforme.

Five nitrogen fixing cyanobacterial strains have been found to contain PsaB2, an additional and divergent gene copy for the Photosystem I reaction center protein PsaB. In all five species the divergent gene, psaB2, is located separately from the normal psaAB operon in the genome. The protein, PsaB2, was recently identified in heterocysts of Nostoc punctiforme sp.

Who would benefit from memory training? A pilot study examining the ceiling effect of concurrent cognitive stimulation.

Diverse effects of memory training were observed in the literature. One possible factor is the amount of concurrent cognitive training received during the training program. In this pilot study, we recruited 24 elderly adults with or without concurrent cognitive stimulations to attend a memory-training program.

Structural and mechanistic investigations of photosystem II through computational methods.

The advent of oxygenic photosynthesis through water oxidation by photosystem II (PSII) transformed the planet, ultimately allowing the evolution of aerobic respiration and an explosion of ecological diversity. The importance of this enzyme to life on Earth has ironically been paralleled by the elusiveness of a detailed understanding of its precise catalytic mechanism. Computational investigations have in recent years provided more and more insights into the structural and mechanistic details that underlie the workings of PSII.

The effectiveness of group voice therapy: a group climate perspective.

Objectives/hypothesis: Group therapy has frequently been adopted as a service delivery model for providing voice therapy. However, currently no literature has focused on understanding the underlying processes that are unique to group therapy, which contribute to treatment success. This study aimed at investigating the role of group climate in voice group therapy.

Hong Kong's first Professor of Pathology and the laboratory of the Royal College of Physicians of Edinburgh.

At a time when the role of the laboratory in clinical medicine and in medical research was evolving rapidly, a young Chinese graduate of the Hong Kong College of Medicine and the University of Edinburgh undertook a period of intensive training at the laboratory of the Royal College of Physicians of Edinburgh that was to play a pivotal role in determining his future career as the first Professor of Pathology at the University of Hong Kong and its first professor of Chinese descent. Chung Yik Wang's subsequent achievements over a span of ten years were a testament to the solid foundation that had been laid during that early period, and was an excellent example of how the skills of medical science could be transferred across continents to best effect. Tragically, Wang's career was cut short when he succumbed to tuberculosis, the disease he had spent many years studying.

15,16-Dihydrotanshinone I, a Compound of Salvia miltiorrhiza Bunge, Induces Apoptosis through Inducing Endoplasmic Reticular Stress in Human Prostate Carcinoma Cells.

5,16-dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge (tanshen root) and was found to be the most effective compound of tanshen extracts against breast cancer cells in our previous studies. However, whether DHTS can induce apoptosis through an endoplasmic reticular (ER) stress pathway was examined herein. In this study, we found that DHTS significantly inhibited the proliferation of human prostate DU145 carcinoma cells and induced apoptosis.

Celecoxib induces heme oxygenase-1 expression in macrophages and vascular smooth muscle cells via ROS-dependent signaling pathway.

The multiple cytoprotective mechanisms of heme oxygenase (HO)-1 make it a promising therapeutic target. This study investigated whether the selective cyclooxygenase (COX)-2 inhibitor, celecoxib, can upregulate HO-1 expression. Murine J774 macrophages and rat aortic vascular smooth muscle cells (VSMCs) were used to study the effect of celecoxib on HO-1 expression.

Naringenin more effectively inhibits inducible nitric oxide synthase and cyclooxygenase-2 expression in macrophages than in microglia.

Macrophages and microglia are thought to account for initial disease progression in acute myocardial infarction and acute ischemic stroke. Before our study, the inhibitory effects of naringenin, a flavonoid, on lipopolysaccharide (LPS)-induced inflammation in macrophages and microglia have not been fully reported and compared. We hypothesized that naringenin can effectively inhibit LPS-induced inflammation of macrophages and microglia at different concentrations, the range of which is broader, with the lowest concentration more easily achieved in macrophages.

Grape seed extract ameliorates tumor necrosis factor-α-induced inflammatory status of human umbilical vein endothelial cells.

Background: Inflammation has played a key role in the causation of atherosclerosis. However, the effects of grape seed extract (GSE) on the pro-inflammatory intracellular signaling, enzyme activity, and inflammatory mediators of endothelial cells have not been sufficiently studied, and less information exists on the comparison between GSE and vitamin C, a well-known antioxidant compound, on their anti-inflammatory properties.

Purpose: We investigated the effects of GSE and vitamin C on the cell viability, oxidative stress, monocyte adhesion, the expression of nuclear factor-κB inhibitor (IκB), intercellular adhesion molecule-1 (ICAM-1) and cyclooxygenase-2 (COX-2), and the production of prostaglandin E(2) (PG E(2)) in TNF-α-treated human umbilical vein endothelial cells (HUVECs).

Oxidative stress initiates DNA damager MNNG-induced poly(ADP-ribose)polymerase-1-dependent parthanatos cell death.

The alkylating agent N-methyl-N'-nitro-N'-nitrosoguanidine (MNNG) can cause excess DNA strand breaks that lead to poly(ADP-ribose)polymerase-1 (PARP-1) overactivation and cell death (parthanatos). However, the detail mechanism of MNNG-induced parthanatos was not well-investigated. In this study, we used MNNG-treated mouse embryonic fibroblasts (MEFs) to elucidate the signaling pathways of MNNG-induced parthanatos.

The formation of the split EPR signal from the S(3) state of Photosystem II does not involve primary charge separation.

Metalloradical EPR signals have been found in intact Photosystem II at cryogenic temperatures. They reflect the light-driven formation of the tyrosine Z radical (Y(Z)) in magnetic interaction with the CaMn(4) cluster in a particular S state. These so-called split EPR signals, induced at cryogenic temperatures, provide means to study the otherwise transient Y(Z) and to probe the S states with EPR spectroscopy.

Carbon monoxide induces cyclooxygenase-2 expression through MAPKs and PKG in phagocytes.

Many biological functions of heme oxygenase (HO) have been attributed to its enzymatic byproduct carbon monoxide (CO). CO has been demonstrated to play an important role in down-regulation of pro-inflammatory cytokines, but few studies have investigated the effects of CO on the cyclooxygenase-2 (COX-2) expression in macrophage. Here, we assessed the induction of COX-2 by CO in macrophage with or without lipopolysaccharide (LPS) stimulation.

AICAR induces cyclooxygenase-2 expression through AMP-activated protein kinase-transforming growth factor-beta-activated kinase 1-p38 mitogen-activated protein kinase signaling pathway.

AMP-activated protein kinase (AMPK), a critical signaling molecule for regulating energy homeostasis, might bi-directionally regulate inflammation, and its action mechanism leading to inflammation is not fully understood. We utilized 5-aminoimidazole-4-carboxamide riboside (AICAR) as a pharmacological activator of AMPK to unveil the effects of and signaling cascades mediated by AMPK on cyclooxygenase (COX)-2 gene expression in rat aortic vascular smooth muscle cells (VSMCs), murine macrophage cell line (J774), and human umbilical vein endothelial cells (HUVECs). Biochemical approaches were further conducted to elucidate interactions among signaling molecules.

Wear-pattern analysis in retrieved tibial inserts of mobile-bearing and fixed-bearing total knee prostheses.

Components from 73 failed knee replacements (TKRs) consisting of rotating-platform, mobile-bearing and fixed-bearing implants were examined to assess the patterns of wear. The patterns were divided into low-grade (burnishing, abrasion and cold flow) and high-grade (scratching, pitting/metal embedding and delamination) to assess the severity of the wear of polyethylene. The rotating-platform group had a higher incidence of low-grade wear on the upper surface compared with the fixed-bearing group.

Investigation of multiphase liquid roughness using an atomic force microscope.

The roughness of a multiphase interface and the associated topography between silicone oil and an alcohol-based fluid were measured with an atomic force microscope (AFM) and compared with the results of calculations based upon a capillary-wave model. According to this theory, the interfacial roughness of a liquid-liquid interface depends on the density, interfacial tension, and temperature of the liquids. Test samples prepared with both silicone oil and an alcohol-based fluid at various volumetric ratios and controlled temperatures were carefully measured.

Functional changes in arteries induced by pulsed high-intensity focused ultrasound.

Continuous high-intensity focused ultrasound (HIFU) at various intensities has been shown to induce functional changes in arteries. The objective of the current study was to investigate the functional changes in arteries when pulsed HIFU is used at various acoustic power levels. Sonication was applied at an ultrasound frequency of 1 MHz with a burst length of 50 ms and a repetition frequency of 1 Hz.

Effect of ultrasound contrast agent dose on the duration of focused-ultrasound-induced blood-brain barrier disruption.

It has been shown that focused ultrasound (FUS) is capable of noninvasive and reversible disruption of the blood-brain barrier (BBB) at target regions when applied in the presence of ultrasound contrast agent (UCA). The purpose of this study was to investigate the effects of UCA dose on the reversibility of BBB disruption induced by the same acoustical power of FUS. Sonications were applied at an ultrasound frequency of 1 MHz with a 5% duty cycle and a repetition frequency of 1 Hz.

Contrast extravasation after bilateral inferior petrosal sinus sampling masquerading as venous subarachnoid haemorrhage.

When performed properly, bilateral inferior petrosal sinus sampling (BIPSS) for adrenocorticotropic hormone (ACTH) is rarely associated with complications. Major complications reported to date include thromboembolism, brain stem infarction, pontine haemorrhage, isolated sixth nerve palsy and venous subarachnoid haemorrhage. We describe a rare case where a predominant contrast extravasation into the subarachnoid space, admixed with a small quantity of venous blood, occurring during BIPSS in a 58-year-old woman with ACTH-dependent Cushing's syndrome, was misinterpreted as venous subarachnoid haemorrhage.