Ultrasound accuracy for brachial plexus pathology

AIM

To determine (a) the accuracy of ultrasound in detecting brachial plexus pathology and (b) outline the advantages and limitations of ultrasound compared to MRI for imaging the brachial plexus.

MATERIAL AND METHODS

cases with clinically suspected brachial plexus pathology were evaluated first by ultrasound, followed by MRI. Patients with prior brachial plexus imaging were excluded. The final diagnosis was based on a combination of ultrasound, MRI, clinical follow-up, and surgical findings. The accuracy of the ultrasound was assessed by comparing the ultrasound and the final diagnoses. The mean clinical follow-up time following ultrasound was 1.8 ± 1.4 years.

RESULTS

Ninety-two (64%) of the 143 cases had normal brachial plexus ultrasound and MRI examinations. Fifty-one (36%) of 143 cases had brachial plexus pathology on MRI, comprising post-radiation fibrosis (n=25, 49%), nerve sheath tumor (n=11, 21%), traumatic injury (n=7, 14%), inflammatory polyneuropathy (n=4, 8%), malignant infiltration (n=2, 4%), desmoid fibromatosis (n=1,2%), and neuralgic amyotrophy (n=1, 2%). Overall diagnostic accuracy of ultrasound for brachial plexus pathology was 98% (140/143), with three discordant cases (neuralgic amyotrophy n=1, inflammatory neuropathy n=1, postradiation fibrosis n=1) regarded as normal on ultrasound assessment. Sensitivity, specificity, and positive and negative predictive value of ultrasound for identifying brachial plexus pathology were 94%, 100%, 100%, and 97%, respectively.

CONCLUSION

Ultrasound identifies brachial plexus pathology with high accuracy and specificity, showing comparable diagnostic efficacy to MRI. Ultrasound can serve as an effective first-line imaging investigation for suspected brachial plexus pathology.

Development of a bioengineered Erwinia chrysanthemi asparaginase to enhance its anti-solid tumor potential for treating gastric cancer

Asparaginase has been traditionally applied for only treating acute lymphoblastic leukemia due to its ability to deplete asparagine. However, its ultimate anticancer potential for treating solid tumors has not yet been unleashed. In this study, we bioengineered Erwinia chrysanthemi asparaginase (ErWT), one of the US Food and Drug Administration-approved types of amino acid depleting enzymes, to achieve double amino acid depletions for treating a solid tumor. We constructed a fusion protein by joining an albumin binding domain (ABD) to ErWT via a linker (GGGGS)5 to achieve ABD-ErS5. The ABD could bind to serum albumin to form an albumin-ABD-ErS5 complex, which could avoid renal clearance and escape from anti-drug antibodies, resulting in a remarkably prolonged elimination half-life of ABD-ErS5. Meanwhile, ABD-ErS5 did not only deplete asparagine but also glutamine for ∼2 weeks. A biweekly administration of ABD-ErS5 (1.5 mg/kg) significantly suppressed tumor growth in an MKN-45 gastric cancer xenograft model, demonstrating a novel approach for treating solid tumor depleting asparagine and glutamine. Multiple administrations of ABD-ErS5 did not cause any noticeable histopathological abnormalities of key organs, suggesting the absence of acute toxicity to mice. Our results suggest ABD-ErS5 is a potential therapeutic candidate for treating gastric cancer.

The oncogenic potential of Rab-like protein 1A (RBEL1A) GTPase: The first review of RBEL1A research with future research directions and challenges

Research on Rab-like protein 1A (RBEL1A) in the past two decades highlighted the oncogenic properties of this gene. Despite the emerging evidence, its importance in cancer biology was underrated. This is the first RBEL1A critical review covering its discovery, biochemistry, physiological functions, and clinical insights. RBEL1A expression at the appropriate levels appears essential in normal cells and tissues to maintain chromosomal stability; however, its overexpression is linked to tumorigenesis. Furthermore, the upstream and downstream targets of the RBEL1A signaling pathways will be discussed. Mechanistically, RBEL1A promotes cell proliferation signals by enhancing the Erk1/2, Akt, c-Myc, and CDK pathways while blunting the apoptotic signals via inhibitions on p53, Rb, and caspase pathways. More importantly, this review covers the clinical relevance of RBEL1A in the cancer field, such as drug resistance and poor overall survival rate. Also, this review points out the bottle-necks of the RBEL1A research and its future research directions. It is becoming clear that RBEL1A could potentially serve as a valuable target of anticancer therapy. Genetic and pharmacological researches are expected to facilitate the identification and development of RBEL1A inhibitors as cancer therapeutics in the future, which could undoubtedly improve the management of human malignancy.

Advances in organ-on-a-chip systems for modelling joint tissue and osteoarthritic diseases

Joint-on-a-chip (JOC) models are powerful tools that aid in osteoarthritis (OA) research. These microfluidic devices apply emerging organ-on-a-chip technology to recapitulate a multifaceted joint tissue microenvironment. JOCs address the need for advanced, dynamic in vitro models that can mimic the in vivo tissue environment through joint-relevant biomechanical or fluidic integration, an aspect that existing in vitro OA models lack. There are existing review articles on OA models that focus on animal, tissue explant, and two-dimensional and three-dimensional (3D) culture systems, including microbioreactors and 3D printing technology, but there has been limited discussion of JOC models. The aim of this article is to review recent developments in human JOC technology and identify gaps for future advancements. Specifically, mechanical stimulation systems that mimic articular movement, multi-joint tissue cultures that enable crosstalk, and systems that aim to capture aspects of OA inflammation by incorporating immune cells are covered. The development of an advanced JOC model that captures the dynamic joint microenvironment will improve testing and translation of potential OA therapeutics.

Toxic Peptide From Palythoa caribaeorum Acting on the TRPV1 Channel Prevents Pentylenetetrazol-Induced Epilepsy in Zebrafish Larvae

PcActx peptide, identified from the transcriptome of zoantharian Palythoa caribaeorum, was clustered into the phylogeny of analgesic polypeptides from sea anemone Heteractis crispa (known as APHC peptides). APHC peptides were considered as inhibitors of transient receptor potential cation channel subfamily V member 1 (TRPV1). TRPV1 is a calcium-permeable channel expressed in epileptic brain areas, serving as a potential target for preventing epileptic seizures. Through in silico and in vitro analysis, PcActx peptide was shown to be a potential TRPV1 channel blocker. In vivo studies showed that the linear and oxidized PcActx peptides caused concentration-dependent increases in mortality of zebrafish larvae. However, monotreatment with PcActx peptides below the maximum tolerated doses (MTD) did not affect locomotor behavior. Moreover, PcActx peptides (both linear and oxidized forms) could effectively reverse pentylenetetrazol (PTZ)-induced seizure-related behavior in zebrafish larvae and prevent overexpression of c-fos and npas4a at the mRNA level. The excessive production of ROS induced by PTZ was markedly attenuated by both linear and oxidized PcActx peptides. It was also verified that the oxidized PcActx peptide was more effective than the linear one. In particular, oxidized PcActx peptide notably modulated the mRNA expression of genes involved in calcium signaling and γ-aminobutyric acid (GABA)ergic-glutamatergic signaling, including calb1, calb2, gabra1, grm1, gria1b, grin2b, gat1, slc1a2b, gad1b, and glsa. Taken together, PcActx peptide, as a novel neuroactive peptide, exhibits prominent anti-epileptic activity, probably through modulating calcium signaling and GABAergic-glutamatergic signaling, and is a promising candidate for epilepsy management.

A mixed-methods study to evaluate the effectiveness and cost-effectiveness of aerobic exercise for primary dysmenorrhea: A study protocol

BACKGROUND AND PURPOSE

Several studies have evaluated the effects of high-intensity aerobic training (HIAT) on pain severity and quality of life (QoL) among women with primary dysmenorrhea. However, to date, no studies have evaluated the effectiveness of HIAT on academic performance or absenteeism or examined the cost-effectiveness of HIAT relative to other treatments in women with primary dysmenorrhea. Furthermore, the mechanisms underlying aerobic exercise-induced analgesia in primary dysmenorrhea remain unclear. The objectives of this study are to: (1) evaluate the effects of HIAT on absenteeism and academic performance among university students, (2) identify the underlying mechanisms associated with aerobic exercise-induced analgesia in primary dysmenorrhea, and (3) determine the cost-effectiveness of HIAT compared with a wait-list control (WLC) group receiving usual care.

METHODS

A sequential, embedded, mixed-methods study design, including a crossover, randomised controlled trial (RCT) and semi-structured focus groups, will be conducted alongside an economic evaluation. A total of 130 women aged 18-24 years will be randomised into either HIAT (n = 65) or wait-list control (n = 65) groups. Primary outcomes will include average pain intensity, absenteeism from university, and academic performance. Primary mediators will include salivary progesterone and prostaglandin F2α levels. Outcome and meditator variables will be assessed at baseline and post-treatment, at 12 and 28 weeks. An economic analysis will be conducted from the societal and healthcare perspective of Hong Kong. Semi-structured focus groups will be conducted at 32 weeks. Of the 130 participants included in the RCT, 70 will be included in the focus groups.

STATISTICAL ANALYSIS

All statistical analyses will be performed on an intention-to-treat basis, using SPSS (version 24). Preliminary analysis using an independent samples t-test and a two-sided, unpaired Student's t-test will be performed to exclude carryover effects and identify within-participant differences in outcome variables between the study periods, respectively. Treatment effects will be evaluated using analysis of variance via a mixed-effects model with fixed effects for intervention, period, and sequence. In all models, random effects will include the participants nested within the sequence as a sampling cluster. The mediation effects will be assessed using the Sobel test. The EQ-5D responses will be converted into utility scores to estimate the gain or loss of quality-adjusted life-years. Seemingly unrelated regression analyses will be used to estimate the total cost differences and effect differences. Qualitative data will be analysed using the process of thematic analysis.

Protective Effects of Melatonin on Neurogenesis Impairment in Neurological Disorders and Its Relevant Molecular Mechanisms

Neurogenesis is the process by which functional new neurons are generated from the neural stem cells (NSCs) or neural progenitor cells (NPCs). Increasing lines of evidence show that neurogenesis impairment is involved in different neurological illnesses, including mood disorders, neurogenerative diseases, and central nervous system (CNS) injuries. Since reversing neurogenesis impairment was found to improve neurological outcomes in the pathological conditions, it is speculated that modulating neurogenesis is a potential therapeutic strategy for neurological diseases. Among different modulators of neurogenesis, melatonin is a particularly interesting one. In traditional understanding, melatonin controls the circadian rhythm and sleep-wake cycle, although it is not directly involved in the proliferation and survival of neurons. In the last decade, it was reported that melatonin plays an important role in the regulation of neurogenesis, and thus it may be a potential treatment for neurogenesis-related disorders. The present review aims to summarize and discuss the recent findings regarding the protective effects of melatonin on the neurogenesis impairment in different neurological conditions. We also address the molecular mechanisms involved in the actions of melatonin in neurogenesis modulation.

Phenotypic characteristics of commonly used inbred mouse strains

The laboratory mouse is the most commonly used mammalian model for biomedical research. An enormous number of mouse models, such as gene knockout, knockin, and overexpression transgenic mice, have been created over the years. A common practice to maintain a genetically modified mouse line is backcrossing with standard inbred mice over several generations. However, the choice of inbred mouse for backcrossing is critical to phenotypic characterization because phenotypic variabilities are often observed between mice with different genetic backgrounds. In this review, the major features of commonly used inbred mouse lines are discussed. The aim is to provide information for appropriate selection of inbred mouse lines for genetic and behavioral studies.

Does aerobic exercise induced-analgesia occur through hormone and inflammatory cytokine-mediated mechanisms in primary dysmenorrhea?

The popular accepted explanation for the pathogenesis of primary dysmenorrhea is elevated levels of uterine prostaglandins. Aetiological studies report that production of prostaglandins is controlled by the sex hormone progesterone, with prostaglandins and progesterone displaying an inverse relationship (i.e. increased progesterone levels reduce prostaglandin levels). Pro-inflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor-alpha [TNF-α]) are also implicated in the pathogenesis of primary dysmenorrhea. High-intensity aerobic exercise is effective for decreasing pain quality and intensity in women with primary dysmenorrhea. However, why and how aerobic exercise is effective for treatment of primary dysmenorrhea remain unclear. Our preliminary non-randomized controlled pilot study to examine the effects of high-intensity aerobic exercise on progesterone, prostaglandin metabolite (13,14-dihydro-15-keto-prostaglandin F2 alpha (KDPGF_2α), TNF-α, and pain intensity found increases in progesterone and decreases in KDPGF_2α, TNF-α, and pain intensity following high-intensity aerobic exercise relative to no exercise. Given these promising preliminary findings, as well as what is known about the pathogenesis of primary dysmenorrhea, we propose the following scientific hypothesis: high-intensity aerobic exercise utilizes hormone (progesterone) and inflammatory cytokine-mediated mechanisms to reduce the pain associated with primary dysmenorrhea.

Overexpression of Mechano-Growth Factor Modulates Inflammatory Cytokine Expression and Macrophage Resolution in Skeletal Muscle Injury

In muscle regeneration, infiltrating myeloid cells, such as macrophages mediate muscle inflammation by releasing key soluble factors. One such factor, insulin-like growth factor 1 (IGF-1), suppresses inflammatory cytokine expression and mediates macrophage polarization to anti-inflammatory phenotype during muscle injury. Previously the IGF-1Ea isoform was shown to be anti-inflammatory. Another isoform of IGF-1, mechano-growth factor (MGF), is structurally and functionally distinct from IGF-1Ea, but its role in muscle inflammation has not yet been characterized. In this study, we hypothesized that MGF expression in muscle injury modulates muscle inflammation. We first investigated changes of transcription and expression of MGF in response to skeletal muscle injury induced by cardiotoxin (CTX) in vivo. At 1–2 days post-injury, Mgf expression was significantly upregulated and positively correlated with that of inflammatory cytokines. Immunostaining revealed that infiltration of neutrophils and macrophages coincided with Mgf upregulation. Furthermore, infiltrating neutrophils and macrophages expressed Mgf, suggesting their contribution to MGF upregulation in muscle injury. Macrophages seem to be the predominant source of MGF in muscle injury, whereas neutrophil depletion did not affect muscle Mgf expression. Given the association of MGF and macrophages, we then studied whether MGF could affect macrophage infiltration and polarization. To test this, we overexpressed MGF in CTX-injured muscles and evaluated inflammatory marker expression, macrophage populations, and muscle regeneration outcomes. MGF overexpression delayed the resolution of macrophages, particularly the pro-inflammatory phenotype. This coincided with upregulation of inflammatory markers. Annexin V-based flow cytometry revealed that MGF overexpression likely delays macrophage resolution by limiting macrophage apoptosis. Although MGF overexpression did not obviously affect muscle regeneration outcomes, the findings are novel and provide insights on the physiological roles of MGF in muscle regeneration.

Amelioration of acute myocardial infarction by saponins from flower buds of Panax notoginseng via pro-angiogenesis and anti-apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Panax notoginseng is traditionally used as an anti-hemorrhagic agent to promote blood circulation without causing "congealed" blood. Furthermore, the flower of P. notoginseng is a popular, traditional medicine taken daily for the preventing of hypertension and for reducing blood cholesterol profiles. Besides, the flower of P. notoginseng contains a higher level of saponins, particularly protopanaxadiol-type ginsenosides, as compared to the root. However, detailed pharmacological studies on this flower have rarely been conducted.

MATERIAL AND METHODS

In this study, the saponins extracted from the flower of P. notoginseng (FS) were examined on the endothelial cell migration assay, chemically induced vascular insufficiency model in zebrafish larvae and myocardial infraction (MI) model in rats, for determination of their pro-angiogenic and therapeutic effects on MI treatment.

RESULTS

Our results demonstrate that FS significantly promoted VEGF-induced migration of human umbilical vein endothelial cells (HUVECs) and partially restored defective intersegmental vessels (ISV) in a chemically induced vascular insufficiency model of zebrafish larvae. When compared to MI group, two weeks post-treatment of FS (25-50mg/kg/day) induced approximately 3-fold upregulation of VEGF mRNA expression and a concomitant increase in blood vessel density in the peri-infarct area of the heart. Moreover, TUNEL analysis indicates a reduction in the mean apoptotic nuclei per field in peri-infarct myocardium upon FS treatment.

CONCLUSIONS

The pro-angiogenic effects of FS demonstrated in in vitro and in vivo experimental models suggest that the purified saponin preparation from flowers of P. notoginseng may potentially provide preventive and therapeutic agent for cardiovascular diseases.

The involvement of transient receptor potential canonical type 1 in skeletal muscle regrowth after unloading-induced atrophy

KEY POINTS

Decreased mechanical loading results in skeletal muscle atrophy. The transient receptor potential canonical type 1 (TRPC1) protein is implicated in this process. Investigation of the regulation of TRPC1 in vivo has rarely been reported. In the present study, we employ the mouse hindlimb unloading and reloading model to examine the involvement of TRPC1 in the regulation of muscle atrophy and regrowth, respectively. We establish the physiological relevance of the concept that manipulation of TRPC1 could interfere with muscle regrowth processes following an atrophy-inducing event. Specifically, we show that suppressing TRPC1 expression during reloading impairs the recovery of the muscle mass and slow myosin heavy chain profile. Calcineurin appears to be part of the signalling pathway involved in the regulation of TRPC1 expression during muscle regrowth. These results provide new insights concerning the function of TRPC1. Interventions targeting TRPC1 or its downstream or upstream pathways could be useful for promoting muscle regeneration.

ABSTRACT

Decreased mechanical loading, such as bed rest, results in skeletal muscle atrophy. The functional consequences of decreased mechanical loading include a loss of muscle mass and decreased muscle strength, particularly in anti-gravity muscles. The purpose of this investigation was to clarify the regulatory role of the transient receptor potential canonical type 1 (TRPC1) protein during muscle atrophy and regrowth. Mice were subjected to 14 days of hindlimb unloading followed by 3, 7, 14 and 28 days of reloading. Weight-bearing mice were used as controls. TRPC1 expression in the soleus muscle decreased significantly and persisted at 7 days of reloading. Small interfering RNA (siRNA)-mediated downregulation of TRPC1 in weight-bearing soleus muscles resulted in a reduced muscle mass and a reduced myofibre cross-sectional area (CSA). Microinjecting siRNA into soleus muscles in vivo after 7 days of reloading provided further evidence for the role of TRPC1 in regulating muscle regrowth. Myofibre CSA, as well as the percentage of slow myosin heavy chain-positive myofibres, was significantly lower in TRPC1-siRNA-expressing muscles than in control muscles after 14 days of reloading. Additionally, inhibition of calcineurin (CaN) activity downregulated TRPC1 expression in both weight-bearing and reloaded muscles, suggesting a possible association between CaN and TRPC1 during skeletal muscle regrowth.

Pharmacological and molecular characterization of functional P2 receptors in rat embryonic cardiomyocytes

Purinergic receptors activated by extracellular nucleotides (adenosine 5'-triphosphate (ATP) and uridine 5'-triphosphate (UTP)) are well known to exert physiological effects on the cardiovascular system, whether nucleotides participate functionally in embryonic heart development is not clear. The responsiveness of embryonic cardiomyocytes (E) 12 to P2 receptor agonists by measuring Ca(2+) influx did not present response to ATP, but responses to P2 agonists were detected in cardiomyocytes taken from E14 and E18 rats. Photometry revealed that the responses to ATP were concentration-dependent with an EC50 of 1.32 μM and 0.18 μM for E14 and E18 cardiomyocytes, respectively. In addition, other P2 agonists were also able to induce Ca(2+) mobilization. RT-PCR showed the presence of P2X2 and P2X4 receptor transcripts on E14 cardiomyocytes with a lower expression of P2X3 and P2X7 receptors. P2X1 and a low level of P2X5 receptor messenger RNA (mRNA) were also expressed at E18. Immunofluorescence data indicated that only P2X2 and P2X4 receptor proteins were expressed in E14 cardiomyocytes while protein for all the P2X receptor subtypes was expressed in E18, except for P2X3 and P2X6. Responses mediated by agonists specific for P2Y receptors subtypes showed that P2Y receptors (P2Y1, P2Y2, P2Y4 and P2Y6) were also present in both E14 and E18 cardiomyocytes. Dye transfer experiments showed that ATP induces coupling of cells at E12, but this response is decreased at E14 and lost at E18. Conversely, UTP induced coupling with five or more cells in most cells from E12 to E18. Our results show that specific P2 receptor subtypes are present in embryonic rat cardiomyocytes, including P2X7 and P2Y4 receptors that have not been identified in adult rat cardiomyocytes. The responsiveness to ATP stimulation even before birth, suggests that ATP may be an important messenger in embryonic as well as in adult hearts.

Adaptive responses of TRPC1 and TRPC3 during skeletal muscle atrophy and regrowth

INTRODUCTION

We assessed the time-dependent changes of transient receptor potential canonical type 1 (TRPC1) and TRPC3 expression and localization associated with muscle atrophy and regrowth in vivo.

METHODS

Mice were subjected to hindlimb unloading for 7 or 14 days (7U, 14U) followed by 3, 7, or 14 days of reloading (3R, 7R, 14R).

RESULTS

Soleus muscle mass and tetanic force were reduced significantly at 7U and 14U and recovered by 14R. Recovery of muscle fiber cross-sectional area was observed by 28R. TRPC1 mRNA was unaltered during the unloading-reloading period. However, protein expression remained depressed through 14R. Decreased localization of TRPC1 to the sarcolemma was observed. TRPC3 mRNA and protein expression levels were decreased significantly during the early phase of reloading.

CONCLUSIONS

Given the known role of these channels in muscle development, changes observed in TRPC1 and TRPC3 may relate closely to muscle atrophy and remodeling processes.

In vivo and ex vivo approaches to studying the biomechanical properties of healing wounds in rat skin

An evaluation of wound mechanics is crucial in reflecting the wound healing status. The present study examined the biomechanical properties of healing rat skin wounds in vivo and ex vivo. Thirty male Sprague-Dawley rats, each with a 6 mm full-thickness circular punch biopsied wound at both posterior hind limbs were used. The mechanical stiffness at both the central and margins of the wound was measured repeatedly in five rats over the same wound sites to monitor the longitudinal changes over time of before wounding, and on days 0, 3, 7, 10, 14, and 21 after wounding in vivo by using an optical coherence tomography-based air-jet indentation system. Five rats were euthanized at each time point, and the biomechanical properties of the wound tissues were assessed ex vivo using a tensiometer. At the central wound bed region, the stiffness measured by the air-jet system increased significantly from day 0 (17.2%), peaked at day 7 (208.3%), and then decreased progressively until day 21 (40.2%) as compared with baseline prewounding status. The biomechanical parameters of the skin wound samples measured by the tensiometer showed a marked reduction upon wounding, then increased with time (all p < 0.05). On day 21, the ultimate tensile strength of the skin wound tissue approached 50% of the normal skin; while the stiffness of tissue recovered at a faster rate, reaching 97% of its prewounded state. Our results suggested that it took less time for healing wound tissues to recover their stiffness than their maximal strength in rat skin. The stiffness of wound tissues measured by air-jet could be an indicator for monitoring wound healing and contraction.

The effect of monochromatic infrared energy on diabetic wound healing

This study examined the effect of monochromatic infrared energy (MIRE) on diabetic wound healing. Fifteen diabetic rats were given MIRE intervention on their skin wounds located on the dorsum and compared with 15 control diabetic rats. Assessments were conducted for each group at weeks 1, 2 and 4 post wounding (five rats at each time point) by calculating the percentage of wound closures (WCs) and performing histological and immunohistochemical staining on sections of wound tissue. Evaluations of WCs and histological examinations of reepithelialisation, cellular content and granulation tissue formation showed no significant difference between the MIRE and the control group at each time point. Through semi-quantitative immunohistochemical staining, the deposition of type I collagen in the MIRE group was found to have improved when compared with the control group at the end of week 2 (P = 0.05). No significant differences in the myofibroblast population were detected between the two groups. In conclusion, MIRE appeared to promote collagen deposition in the early stage of wound healing in diabetic rats, but the overall wound healing in the MIRE group was not significantly different from that of the control group.

Expression and association of TRPC1 with TRPC3 during skeletal myogenesis

INTRODUCTION

TRPC1 and TRPC3 proteins are widely expressed in skeletal muscles in forming calcium-permeable channels. Herein we characterize the expression pattern of TRPC transcripts during skeletal myogenesis in C2C12 myoblasts.

METHODS

We used polymerase chain reaction and Western blotting to detect expression levels, immunohistochemistry for subcellular localization, and co-immunoprecipitation techniques to assess interaction.

RESULTS

TRPC1 localizes to the cytoplasm and is enriched in the perinuclear region in undifferentiated myoblasts. Expression of TRPC1 increases significantly during myogenesis and resides mainly in differentiated myocytes and myotubes. TRPC3 is absent in undifferentiated myoblasts, is dramatically upregulated in differentiated culture, and is preferentially expressed in myotubes. Physical interaction of TRPC1-TRPC3 was observed, suggesting the possible existence of heteromers.

CONCLUSIONS

Expression of TRPC1 and TRPC3 is tightly regulated during myogensis. Evidence of TRPC1-TRPC3 interaction was first demonstrated in a muscle cell line. The functional consequences of this interaction remain to be established.

Electrical stimulation influences satellite cell proliferation and apoptosis in unloading-induced muscle atrophy in mice

Muscle atrophy caused by disuse is accompanied by adverse physiological and functional consequences. Satellite cells are the primary source of skeletal muscle regeneration. Satellite cell dysfunction, as a result of impaired proliferative potential and/or increased apoptosis, is thought to be one of the causes contributing to the decreased muscle regeneration capacity in atrophy. We have previously shown that electrical stimulation improved satellite cell dysfunction. Here we test whether electrical stimulation can also enhance satellite cell proliferative potential as well as suppress apoptotic cell death in disuse-induced muscle atrophy. Eight-week-old male BALB/c mice were subjected to a 14-day hindlimb unloading procedure. During that period, one limb (HU-ES) received electrical stimulation (frequency: 20 Hz; duration: 3 h, twice daily) while the contralateral limb served as control (HU). Immunohistochemistry and western blotting techniques were used to characterize specific proteins in cell proliferation and apoptosis. The HU-ES soleus muscles showed significant improvement in muscle mass, cross-sectional area, and peak tetanic force relative to the HU limb (p<0.05). The satellite cell proliferative activity as detected within the BrdU+/Pax7+ population was significantly higher (p<0.05). The apoptotic myonuclei (detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) and the apoptotic satellite cells (detected by cleaved Poly [ADP-ribose] polymerase co-labeled with Pax7) were reduced (p<0.05) in the HU-ES limb. Furthermore the apoptosis-inducing factor and cleaved caspase-3 were down-regulated while the anti-apoptotic Bcl-2 protein was up-regulated (p<0.05), in the HU-ES limb. These findings suggest that the electrical stimulation paradigm provides an effective stimulus to rescue the loss of myonuclei and satellite cells in disuse muscle atrophy, thus maintaining a viable satellite cell pool for subsequent muscle regeneration. Optimization of stimulation parameters may enhance the outcome of the intervention.

Dynamic expression of Dab2 in the mouse embryonic central nervous system

BACKGROUND

Dab2, one of two mammalian orthologs of Drosophila Disabled, has been shown to be involved in cell positioning and formation of visceral endoderm during mouse embryogenesis, but its role in neuronal development is not yet fully understood. In this report, we have examined the localization of the Dab2 protein in the mouse embryonic central nervous system (CNS) at different developmental stages.

RESULTS

Dab2 protein was transiently expressed in rhombomeres 5 and 6 of the developing hindbrain between E8.5 and E11.5, and in the floor plate of the neural tube from E9.5 to E12.5, following which it was no longer detectable within these regions. Dab2 protein was also identified within circumventricular organs including the choroid plexus, subcommissural organ and pineal gland during their early development. While Dab2 was still strongly expressed in the adult choroid plexus, immunoreactivity within the subcommissural organ and pineal gland was lost after birth. In addition, Dab2 was transiently expressed within a subpopulation of Iba1-positive mononuclear phagocytes (including presumed microglial progenitors) within the neural tube from E10.0 and was lost by E14.5. Dab2 was separately localized to Iba1 positive cells from E9.5 and subsequently to F4/80 positive cells (mature macrophage/myeloid-derived dendritic cells) positioned outside the neural tube from E12.5 onwards, implicating Dab2 expression in early cells of the mononuclear phagocyte lineage. Dab2 did not co-localize with the pan-neuronal marker PGP9.5 at any developmental stage, suggesting that Dab2 positive cells in the developing CNS are unlikely to be differentiating neurons.

CONCLUSION

This is the first study to demonstrate the dynamic spatiotemporal expression of Dab2 protein within the CNS during development.

Expression of P2X purinoceptors during rat brain development and their inhibitory role on motor axon outgrowth in neural tube explant cultures

Extracellular ATP is well known as a neurotransmitter and neuromodulator in the CNS of adults. However, little is known about the involvement of ATP during the development of mammalian brain. In the present study, we have examined the expression pattern of P2X receptor subtype mRNA and protein during perinatal rat brain development (from embryonic day (E) 10 to postnatal day (P) 16 brain). While P2X3 receptors appeared early at E11, they declined in the stages that follow. P2X2 and P2X7 receptors were expressed from E14 onwards, while P2X4, P2X5 and P2X6 receptors were expressed from P1 onwards. P2X1 receptor expression was not observed in any of the developmental ages examined. We investigated the effect of 100 microM ATP and alpha,beta-methylene ATP (alpha,beta-meATP; selective agonist for P2X1, P2X2/3 and P2X3 receptors) on motor axon outgrowth in collagen-embedded neural tube explant cultures. Both ATP- and alpha,beta-meATP-treated neural tubes showed a significant reduction in neurite outgrowth compared with the control explants. This inhibitory effect could not be reproduced by uridine triphosphate. In conclusion, all P2X receptor subtypes, except for P2X1, were strongly represented in the developing rat brain. ATP was shown to inhibit motor axon outgrowth during early embryonic neurogenesis, most likely via the P2X3 receptor. It is speculated that P2X7 receptors may be involved in programmed cell death during embryogenesis and that P2X4, P2X(5) and P2X6 receptors might be involved in postnatal neurogenesis.

P2X and P2Y purinergic receptors on human intestinal epithelial carcinoma cells: effects of extracellular nucleotides on apoptosis and cell proliferation

Extracellular nucleotides interact with purinergic receptors, which regulate ion transport in a variety of epithelia. With the use of two different human epithelial carcinoma cell lines (HCT8 and Caco-2), we have shown by RT-PCR that the cells express mRNA for P2X1, P2X3, P2X4, P2X5, P2X6, P2X7, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, and P2Y12 receptors. Protein expression for P2Y1 and P2Y2 receptors was also demonstrated immunohistochemically, and P2X receptor subtype protein was present in the following decreasing order: P2X4 > P2X7 > P2X1 > P2X3 > P2X6 > P2X5 >> P2X2. The functional presence of P2X7, P2Y1, P2Y2, and P2Y4 receptors was shown based on the effect of extracellular nucleotides on apoptosis or cell proliferation, and measurement of nucleotide-dependent calcium fluxes using a fluorometric imaging plate reader in the presence of different selective agonists and antagonists. ATP, at high concentrations, induced apoptosis through ligation of P2X7 and P2Y1 receptors; conversely, ATP, at lower concentrations, and UTP stimulated proliferation, probably acting via P2Y2 receptors. We therefore propose that stimulation or dysfunction of purinergic receptors may contribute at least partially to modulation of epithelial carcinoma cell proliferation and apoptosis.

Abundant and dynamic expression of G protein-coupled P2Y receptors in mammalian development

Extracellular ATP mediates diverse biological effects by activating two families of receptors, the P2X and P2Y receptors. There is growing evidence to show that activation of G protein-coupled P2Y receptors can produce trophic effects in many cell types. Yet the expression and function of the P2Y receptors in development has rarely been studied and has never been investigated in mammalian development. This study used the reverse transcription-polymerase chain reaction and immunohistochemistry to demonstrate the abundant and dynamic expression of P2Y receptors in rat development. These receptors were expressed in a wide range of embryonic structures, notably somites, skeletal muscle, the central and peripheral nervous system, the heart, lung, and liver. All the P2Y receptors studied were expressed as early as embryonic day 11, when most embryonic organs were far from being functional and still in the process of being formed. P2Y receptor proteins were strongly expressed in temporary, developmental structures that do not have a correlate in the adult animal, including the somites (P2Y1, P2Y2, and P2Y4) and the floor plate of the neural tube (P2Y1). P2Y receptors were also dynamically expressed, with receptor mRNA and protein being both up- and down-regulated at different developmental stages. The down-regulation of the P2Y1, 2, and 4 receptor proteins in skeletal muscle and heart, and the disappearance of the P2Y4 receptor from the brainstem and ventral white matter of the spinal cord postnatally, demonstrated that many P2Y receptors were likely to be involved in functions specific to embryonic life. Thus, these findings strongly suggest that P2Y receptors play an important role in the development of many tissues, and pioneer further studies into the role of purinergic signalling in development.

Acute vertebral body compression fractures: discrimination between benign and malignant causes using apparent diffusion coefficients

Diffusion weighted MRI was performed on patients with acute vertebral body compression. The usefulness of the apparent diffusion coefficient (ADC) in differentiating between benign and malignant fractures was evaluated. A total of 49 acute vertebral body compression fractures were found in 32 patients. 25 fractures in 18 patients were due to osteoporosis, 18 fractures in 12 patients were histologically proven to be due to malignancy, and 6 fractures in 2 patients were due to tuberculosis. Signal intensities on T(1) weighted, short tau inversion recovery (STIR) and diffusion weighted images were compared. ADC values of normal and abnormal vertebral bodies were calculated. Except for two patients with sclerotic metastases, benign acute vertebral fractures were hypointense and malignant acute vertebral fractures were hyperintense with respect to normal bone marrow on diffusion weighted images. Mean combined ADCs (ADC(cmb); average of the combined ADCs in the x, y and z diffusion directions) were 0.23 x 10(-3) mm(2) s(-1) in normal vertebrae, 0.82 x 10(-3) mm(2) s(-1) in malignant acute vertebral fractures and 1.94 x 10(-3) mm(2) s(-1) in benign acute vertebral fractures. The differences between ADC(cmb) values were statistically significant (p<0.001). The ADC is useful in differentiating benign from malignant acute vertebral body compression fractures, but there may be overlapping ADC values between malignant fractures and tuberculous spondylitis.

Localization of P2X3 receptors and coexpression with P2X2 receptors during rat embryonic neurogenesis

It is well known that extracellular ATP mediates rapid excitatory signaling by means of the ionotropic P2X receptors. One of its subunits, the P2X(3) receptor, is well documented to be associated with sensory innervation in adult animals. It is speculated that the P2X(3) receptor may have already been present in the early sensory system. The aim of this study was to investigate the distribution of the P2X(3) receptor during neurogenesis by using immunohistochemistry on rat embryos from embryonic day (E)9.5-18.5. The P2X(3) receptor was first identified in the hindbrain neural tube and the sensory ganglia in E11-11.5 embryos. At E14.5, the optic tract and retina, nucleus tractus solitarius, mesencephalic trigeminal nucleus, and sensory nerves in both respiratory and digestive tract showed positive staining. The facial nucleus, the prepositus hypoglossal nucleus, and the sympathetic ganglia also showed P2X(3) immunoreactivity, even though these are not sensory associated. P2X(3) immunoreactivity was detected in the vestibular nucleus, the nerves in mesentery, bladder, and kidney in E16.5 and in nerves in vibrissae in E18.5. P2X(3) immunoreactivity in the facial nucleus, spinal trigeminal tract, the mesencephalic trigeminal nucleus, and the vestibular nucleus were undetectable in postnatal day 16 rat brainstem. The P2X(3) receptor was coexpressed with the P2X(2) receptor in nucleus tractus solitarius, dorsal root ganglion, nodose ganglion, and the taste bud in E16.5 embryo, which was 5 days later than the first appearance of the native P2X(3) receptor. In summary, we present a detailed expression pattern of the P2X(3) receptor during neurogenesis and report that P2X(3) immunoreactivity is down-regulated in early postnatal brainstems.

Synthesis, structural characterization, and photophysics of dinuclear gold(II) complexes [(Au(dppn)Br)(2)](PF(6))(2) and [(Au(dppn)I)(2)](PF(6))(2) with an unsupported Au(II)-Au(II) Bond

A series of novel dinuclear gold(II) complexes having an unsupported Au(II)-Au(II) bond with well-defined oxidation state at the gold center were synthesized. Red shifts in both the low-energy absorption and emission bands were observed upon increasing the donor ability of the coordinated halogen atoms.

Palladium(II) and platinum(II) analogues of luminescent diimine Triangulo complexes supported by triply bridging sulfide ligands: structural and spectroscopic comparisons

Reaction of [M(L-L)Cl(2)] [M = Pd, Pt; L-L = 4,4'-di-tert-butyl-2,2'-bipyridine ((t)Bu(2)bpy), 4,4'-dimethylcarboxylate-2,2'-bipyridine ((CO(2)Me)(2)bpy), bis(diphenylphosphino)methane (dppm)] with Na(2)S in refluxing methanol afforded [M(3)((t)Bu(2)bpy)(3)(mu(3)-S)(2)](2+) [M = Pd (1a), Pt (2a)], [M(3)((CO(2)Me)(2)bpy)(3)(mu(3)-S)(2)](2+) [M = Pd (1b), Pt (2b)], and [Pt(3)(dppm)(3)(mu(3)-S)(2)](2+) (3) as perchlorate salts. X-ray crystal analysis revealed that 1a, 1b, 2a, and 3 have triangular M(3)S(2) core structures. The three metal atoms in 1a, 2a, and 3 form virtual equilateral triangles with intramolecular Pd-Pd and Pt-Pt separations of 3.027(1)-3.065(1) and 3.104(1)-3.154(1) A, respectively. An isosceles triangle of Pd(3) atoms is observed in the molecular structure of 1b. The (1)MLCT absorption of 2a and 2b appears at 415 and 448 nm, respectively, in dichloromethane and is significantly red-shifted from the lowest energy absorption band of the Pd(3) analogues. Complex 1a exhibits weak photoluminescence in the solid state at 77 and 298 K (uncorrected lambda(max) 760 and 730 nm, respectively) while the 77 K solid-state emission of 1b (uncorrected lambda(max) 760 nm) is also weak. At 77 K, complexes 2a, 2b, and 3 display broad unstructured emissions at lambda(max) 616-630 nm in the solid state. Ligand-field excited states are tentatively assigned for these emissions.

Compounds from Kadsura ananosma

The 18-(13-->12 beta)-abeo-lanostene triterpenoid acid, ananosic acid A (1), and the dibenzocyclooctadiene lignan, ananosin A (2), were isolated from the stem bark of Kadsura ananosma. Their structures were elucidated by extensive spectral studies and the structure of 1 was confirmed by single crystal X-ray diffraction analysis.

Substrate-Binding reactions of the 3[dsigma*psigma] excited state of binuclear gold(I) complexes with bridging bis(dicyclohexylphosphino)methane ligands: emission and time-resolved absorption spectroscopic studies

The complexes [Au2(dcpm)2]-Y2 (dcpm = bis(dicyclohexylphosphino)methane; Y=ClO4 (1), PF6- (2), CF3SO3- (3), Au(CN)2- (4), Cl- (5), SCN (6) and I- (7)) were prepared, and the structures of 1 and 4-7 were determined by X-ray crystallography. Complexes 1-4 display intense phosphorescence with lambdamax at 360-368 nm in the solid state at room temperature as well as in glassy solutions at 77 K. The solid-state emission quantum yields of the powdered samples are 0.37 (1), 0.74 (2), 0.53 (3) and 0.12 (4). Crystalline solid 5 displays both high-energy UV (lambdamax = 366 nm) and low-energy visible emissions (lambdamax = 505 nm) at room temperature, whereas either 6 or 7 shows only an intense emission with lambdamax at 465 or 473 nm, respectively. All the complexes in degassed acetonitrile solutions exhibit an intense phosphorescence with lambdamax ranging from 490 to 530 nm. The high-energy UV emission is assigned to the intrinsic emission of the 3[dsigma*psigma] excited state of [Au2(dcpm)2]2+, whereas the visible emission is attributed to the adduct formation of the triplet excited state with the solvent/counterion. The quenching rate constants of the visible emission of [Au2(dcpm)2]2+ in acetonitrile by various anions are 6.08 x 10(5) (ClO4-), 9.18 x l0(5) (PF6 ), 1.55 x 10(7) (Cl-) and 4.06 x 10(9) (I-) mol(-1) dm3s(-1). The triplet-state difference absorption spectra of 1-4 in acetonitrile show an absorption band with lambdamax at 350 nm and a shoulder/absorption maxima at 395-420 nm; their relative intensities are dependent upon the halide ion present in solution. Substrate binding reactions of the 3[dsigma*psigma] excited state with halide (X-) to give [Au2(dcpm)2X]+* would account for the lower energy absorption maxima in the triplet-state difference absorption spectra. With iodide as the counterion, complex 7 undergoes a photoinduced electron-transfer reaction with I- to give the radical anion I2-.

Organic light-emitting materials based on bis(arylacetylide)platinum(II) complexes bearing substituted bipyridine and phenanthroline ligands: photo- and electroluminescence from 3MLCT excited states

We present the synthesis and photophysical and electroluminescent properties for a series of platinum(II) alpha-diimine bis(arylacetylide) complexes. The molecular structures of five derivatives have been elucidated by X-ray crystallography. Intermolecular pi-pi interactions (between aromatic diimine and phenylacetylide moieties) are apparent in the crystal lattices of two of these. All bis(phenylacetylide) derivatives exhibit intense triplet metal-to-ligand charge transfer (MLCT) photoluminescence in the solid state and in fluid solutions at room temperature. The impact of different solvents, substituents on the diimine ligands, and complex concentrations upon their emissive behavior have been examined and demonstrates that their emission energies can be systematically modified. Application of the 3MLCT excited state of the [Pt(alpha-diimine) (C(triple bond)CPh)2] materials in single- and double-layer organic light-emitting devices are described. The bis(butadiynyl) complex [Pt(4,4'-dtbpy)(C(triple bond)C-C(triple bond)CPh)2] (dtbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) displays strong solid-state and solution phosphorescence at 77 and 298 K; the associated excited state is proposed to arise from both acetylenic 3pi pi*(C(triple bond)C-C(triple bond)CPh) and 3MLCT [Pt --> pi*(diimine)] transitions.

Photoluminescent metal-sulfur clusters derived from tetrathiometalates: metal-to-metal charge-transfer excited states of d0-d10 heterobimetallic sulfido clusters with bulky phosphine ligands

Reactions of MS4(2-) (M = Mo, W) with M'(PCy3)X (M'=Ag/Au, X= ClO4/Cl) and [Cu2(dcpm)2(MeCN)2](ClO4)2 (dcpm = bis(dicyclohexylphosphino)methane) afforded heterometallic sulfido clusters [M'2(PCy3)2(MS4)] (M=Mo, M'=Au: 2; M=W, M'=Ag: 3, Au: 4) and [Cu4(dcpm)4(MS4)](ClO4)2 (M=Mo: 5 x (ClO4)2, W: 6 x (ClO4)2), all of which, except 4, have been characterized by X-ray structure determination. Clusters 5 x(ClO4)2 and 6 x (ClO4)2 feature unusual 16-membered [Cu4P5C4] metallamacrocycles formed on the respective tetrathiometalate anion templates and have unusually long Cu-S bonds and Cu...M distances for metal sulfur clusters that contain a saddle-shaped [Cu4MS4] core. Low-energy absorption bands are observed in their electronic spectra at approximately 562 and 467 nm, respectively, assignable to MMCT transitions; quasireversible reduction waves are observed with E(1/2) = -1.43 (52+) and -1.78 V (62+) versus FeCp2(0/+); and they are emissive either in the solid state or in solution. The emission of 6(2+) can be quenched by both electron acceptors, such as methylviologen, or electron donors, such as aromatic amines, with the excited state reduction potential E(62+*/6+) estimated to be approximately 1.13V versus a normal hydrogen electrode.

Elfin is expressed during early heart development

Elfin (previously named CLIM1) is a protein that possesses an N-terminal PDZ domain and a C-terminal LIM domain. It belongs to the family of Enigma proteins. Enigma proteins are a family of cytoplasmic proteins that contain an N-terminal PDZ domain and a series of C-terminal LIM domains. By virtue of these two protein interacting domains, Enigma proteins are capable of protein-protein interactions. It has been proposed that Enigma proteins may act as adapters between kinases and the cytoskeleton. We have previously shown that Elfin is most abundantly expressed in the heart and it colocalizes with alpha-actinin 2 at the Z-disks of the myocardium. In this report, Elfin was shown to localize at the actin stress fibers of myoblasts, as revealed by green fluorescent protein (GFP) tagging. In situ hybridization and immunostaining showed that Elfin expression begins at an early stage in mouse development and is present throughout the developing heart. Taken together, our experimental results suggest that Elfin may play an important role in myofibrillogenesis and heart development.

SPARC (secreted protein acidic and rich in cysteine) induces apoptosis in ovarian cancer cells

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular Ca(2+)-binding matricellular glycoprotein that associates with cell populations undergoing migration, morphogenesis, and differentiation. Studies on endothelial cells have established that its principal functions in vitro are counteradhesion and antiproliferation. The mechanism(s) underlying these antitumor effects is unknown. In this study, we showed that SPARC expression in ovarian cancer cells is inversely correlated with the degree of malignancy. The immunohistochemical data presented here confirmed the importance of diminished SPARC expression in ovarian cancer development. Treating human ovarian surface epithelial cells and ovarian cancer cells with SPARC revealed that as SPARC inhibits the proliferation of both normal and cancer cells, it induces apoptosis only in cancer cells. This observation indicates that down-regulation of SPARC is essential for ovarian carcinogenesis as cancer cells become sensitized to the apoptotic activity of SPARC during malignant transformation. We also showed here the first direct evidence that putative SPARC receptors are present on ovarian epithelial cells. Their levels are higher in human ovarian surface epithelial cells than cancer cells. Binding of SPARC to its receptor is likely to trigger tissue-specific signaling pathways that mediate its tumor suppressing functions. Decrease in ligand-receptor interaction by the down-regulation of SPARC and/or its receptor is essential for ovarian carcinogenesis.

Syntheses, photophysics, and photochemistry of trinuclear copper(I) thiolate and hexanuclear copper(I) selenolate complexes: X-ray crystal structures of [Cu(6)(mu-dppm)4(mu(3)-SePh)4](BF(4))2 and [Cu(6)(mu-(Ph(2)P)(2)NH(4))(mu(3)-SePh)4](BF(4)2

A series of trinuclear copper(I) thiolate complexes, [Cu(3)(mu-dppm)(3)(mu(3)-SR)(2)]BF(4) (R = C(6)H(4)Cl-4, C(6)H(4)CH(3)-4, C(6)H(4)OCH(3)-4, C(6)H(4)(OCH(3))(2)-3,4, C(6)H(4)-benzo-15-crown-5, or (t)()Bu), [Cu(3)(mu-dppm)(3)(mu(3)-S(t)()Bu)](BF(4))(2), and [Cu(3)(mu-dppm)(3)(mu(3)-SR)(mu(3)-Cl)]BF(4) (R = C(6)H(4)CH(3)-4, C(6)H(4)(t)()Bu-4, or C(6)H(4)(CH(3))(3)-2,4,6) and two hexanuclear copper(I) selenolate complexes, [Cu(6)(mu-P(wedge)P)(4)(mu(3)-SePh)(4)](BF(4))(2) (P(wedge)P = dppm, (Ph(2)P)(2)NH), have been synthesized, and their photophysical properties have been studied. The X-ray crystal structures of both copper(I) selenolate complexes have been determined. These complexes have been shown to exhibit long-lived low-energy emission in solution, attributed to an excited state of predominantly ligand-to-metal charge-transfer [chalcogenolate to copper(I)] origin.

Interaction between dioxoruthenium(VI) porphyrins and hydroxylamines: coordination of N-substituted hydroxylamine to ruthenium and X-ray crystal structures of ruthenium complexes with a unidentate nitrosoarene ligand

The interactions between dioxoruthenium(VI) porphyrins 1 with N-phenylhydroxylamine or unsubstituted hydroxylamine are described. Reaction of complexes 1 with excess PhNHOH leads to isolation of bis(nitrosobenzene)ruthenium(II) porphyrins 3 and mono(nitrosobenzene)ruthenium(II) porphyrins 4. Both the types of ruthenium complexes are characterized by 1H NMR, IR, and UV/Vis spectroscopy, and mass spectrometry. The X-ray structure determinations on [Ru(II)(TPP)(PhNO)2] (3a), [Ru(II)(2,6-Cl-TPP)(PhNO)2] (3e), and [Ru(II)(4-MeO-TPP)(PhNO)(PhNH2)] (4d) (TPP tetraarylporphyrin) disclose a unidentate nitrosoarene coordination in all these complexes, with Ru-N(PhNO) bond lengths of 2.003(3) (3a, average), 1.991(3) (3e, average), and 2.042(2) A (4d). In the case of 4d, the Ru-N(PhNH2) bond length is found to be 2.075(3) A. Mechanistic investigations reveal the formation of intermediates [Ru(II)(Por)(PhNO)(PhNHOH)] (5; Por=porphyrin), a ruthenium complex with N-substituted hydroxylamine ligand, in the "1 + PhNHOH" system. The Ru-NH(OH)Ph moiety in 5 undergoes no rapid exchange with free PhNHOH in solution at room temperature, as revealed by 1H NMR spectroscopy. Unlike the interaction between complexes 1 and PhNHOH, reaction of such complexes with NH2OH affords nitrosylruthenium(II) porphyrins [Ru(II)(Por)(NO)(OH)] (6).

Luminescent mu-ethynediyl and mu-butadiynediyl binuclear gold(I) complexes: observation of (3)(pi pi*) emissions from bridging C(n)(2-) units

The synthesis and X-ray structural and spectroscopic characterization for LAuC triple bond CAuL x 4CHCl(3) and LAuC triple bond C--C triple bond CAuL x 2CH(2)Cl(2) (1 x 4CHCl(3) and 2 x 2CH(2)Cl(2), respectively; L = PCy(3), tricyclohexylphosphine) are reported. The bridging C(n)(2-) units are structurally characterized as acetylene or diacetylene units, with C triple bond C distances of 1.19(1) and 1.199(8) A for 1 x 4CHCl(3) and 2 x 2CH(2)Cl(2), respectively. An important consequence of bonding to Au(I) for the C(n)(2-) moieties is that the lowest-energy electronic excited states, which are essentially acetylenic (3)(pi pi*) in nature, acquire sufficient allowedness via Au spin-orbit coupling to appear prominently in both electronic absorption and emission spectra. The origin lines for both complexes are well-defined and are observed at 331 and 413 nm for 1 and 2, respectively. Sharp vibronic progressions corresponding to v(C triple bond C) are observed in both emission and absorption spectra. The acetylenic (3)(pi pi) excited state of 2 has a long lifetime (tau(0) = 10.8 mus) in dichloromethane at room temperature and is a powerful reductant (E degrees [Au(2)(+)/Au(2)] < or = -1.85 V vs SSCE).

Synthesis, emission, and electrochemical properties of luminescent dinuclear zinc(II) chalcogenolate complexes. Dynamic 1H NMR studies and X-ray crystal structure of [(bpy)Zn2(SC6H4-Cl-p)(mu-SC6H4-Cl-p)(mu-OAc)2]

A series of novel luminescent dinuclear zinc(II) diimine complexes with bridging chalcogenolate ligands have been synthesized, in which the two zinc atoms were found to exist in different coordination environment. The luminescence and electrochemical behavior of these complexes have been studied. These complexes have also been shown to exhibit dynamic fluxional behavior in solution due to an exchange of the bridging and terminal thiolate ligands. The mechanism and kinetics of which have been investigated by variable-temperature 1H NMR studies. The X-ray crystal structure of [(bpy)Zn2(SC6H4-Cl-p)(mu-SC6H4-Cl-p)(mu-OAc)2] has also been determined.

Bis axial ligation of simple imine and methyleneamido groups by ruthenium porphyrins

Bis(N-ethylideneethanamine)ruthenium(ii) porphyrins, [Ru11(Por)(N(Et)=CHMe)2] (Por=TTP, 4-Cl-TPP), were prepared by the reaction of dioxoruthenium(VI) porphyrins with triethylamine in approximately 85% yields. The reaction between dioxoruthenium(VI) porphyrins and benzophenone imine afforded bis(diphenylmethyleneamido)ruthenium(IV) porphyrins, [Ru(IV)(Por)(N=CPh2)2] (Por=TTP, 3,4,5-MeO-TPP), in approximately 65% yields. These new classes of metalloporphyrins were characterized by 1H NMR, UV/Vis, and IR spectroscopy as well as by mass spectrometry and elemental analysis. The X-ray crystallographic structures of [Ru(II)(TTP)(N(Et)=CHMe)2] and [Ru(IV)(3,4,5-MeO-TPP)(N=CPh2)2] revealed an axial Ru-N bond length of 2.115(6) A for the imine complex and 1.896(8) A for the methyleneamido complex. Each of the N=CPh2 axial groups in [Ru(IV)(3,4,5-MeO-TPP)(N=CPh2)2] adopts a linear coordination mode with a corresponding Ru-N-C angle of 175.9(9)degrees. Spectral and structural studies revealed essentially single bonding character for the bis(imine) complexes but a multiple bonding character for the bis(methyleneamido) complexes with respect to their axial Ru-N bonds.

A new trinortriterpenoid from Cleome chrysantha

A new trinortriterpenoid, 1-epibrachyacarpone, was isolated from aerial parts of Cleome chrysantha. Its structure was elucidated as 1 by NMR investigations and X-ray crystallographic studies.

Ruthenium complexes with a terminal hydrazido ligand. Synthesis, spectroscopy, and X-ray crystal structure

Bis(1,1-diphenylhydrazido(1-))ruthenium(IV) porphyrins, [Ru(IV)(Por)(NHNPh2)2] (Por = TPP, TTP, 4-Cl-TPP, 4-MeO-TPP), were prepared in approximately 60% yields through the reaction of dioxoruthenium(VI) porphyrins, [Ru(VI)(Por)O2], with 1,1-diphenylhydrazine in ethanol. This new type of ruthenium complex has been characterized by 1H NMR, IR, UV-vis, and FABMS with elemental analysis. The crystal structure of [Ru(IV)(TTP)(NHNPh2)2], which reveals an eta1-coordination mode for both hydrazido axial ligands, has been determined. The average Ru-NHNPh2 distance and Ru-N-N angle were found to be 1.911(3) A and 141.1(3) degrees, respectively. The porphyrin ring exhibits a ruffling distortion that is unprecedentedly large for ruthenium complexes with simple porphyrinato ligands (such as TTP). This is probably due to the steric effect of the axial hydrazido(1-) ligands.

Bcl-2 and p53 protein expression, apoptosis, and p53 mutation in human epithelial ovarian cancers

Bcl-2 and p53 gene products have been both linked to cell death by apoptosis. In the present study, we examined the relationship of Bcl-2 and p53 protein expression, p53 mutation and apoptosis in normal human ovaries and different types of human ovarian epithelial tumors by immunohistochemical localization, in situ terminal transferase-mediated dUTP nick end labeling and polymerase chain reaction-single strand conformation polymorphism. It was found that Bcl-2 expressed strongly in the surface epithelium of normal ovaries and benign and borderline ovarian tumors but weakly in the malignant tumors. On the contrary, strong protein expression of p53 was found in 54% (25/46) of the malignant epithelial tumors examined but similar expression of p53 was not observed in borderline and benign tumors and normal ovarian surface epithelium. A significant inverse correlation between Bcl-2 and p53 expression was found in the malignant ovarian tumors examined. p53 gene mutation at exons 5-11 was however not a pre-requisite for p53 expression in both borderline and malignant tumors. Apoptotic activities, as reflected by apoptotic indices, were low in normal ovarian surface epithelium and benign tumors but were increased in borderline and malignant tumors, with the highest average apoptotic index found in grade III malignant tumors. Statistical analyses showed a positive correlation between apoptosis and p53 expression, but similar correlation was not found between apoptosis and Bcl-2 expression. Our results also indicate that although expression of Bcl-2 is important during ovarian carcinogenesis, the Bcl-2 protein may have other roles to play apart from being a modulator of apoptosis in human ovarian epithelial cancers.

Luminescent mononuclear and binuclear cyclometalated palladium(II) complexes of 6-phenyl-2,2 bipyridines: spectroscopic and structural comparisons with platinum(II) analogues

The mononuclear cyclometalated Pd(II) complexes [Pd(L1)X] (HL1 = 6-phenyl-2,2'-bipyridine; X = Cl, la; Br, 1b; I, 1c), [Pd(L1)PPh3]+ (1d), [Pd(L2-5)Cl] [2a-5a, HL2-5 = 4-(aryl)-6-phenyl-2,2'-bipyridine; aryl = phenyl (2), 4-chlorophenyl (3), 4-tolyl (4), 4-methoxyphenyl (5)] and the binuclear derivatives [Pd2(L1-5)2(mu-dppm)]2+ (1e-5e, dppm = bis(diphenylphosphino)methane) and [Pd2(L1)2(mu-dppCs)]2+, (1f, dppC5 = 1,5-bis(diphenylphosphino)pentane) were prepared. The crystal structures of 1d(ClO4), 1e(ClO4)2 x DMF, and 2e(ClO4)2 have been determined by X-ray crystallography. The magnitude of the Pd-Pd distances in le and 2e (3.230(1) and 3.320(2) A, respectively) suggest minimal metal-metal interaction, although pi-stacking of the aromatic ligands (interplanar separations 3.34 and 3.35 A, respectively) is evident. All complexes display low-energy UV absorptions at lambda approximately 390 nm, which are tentatively assigned to 1MLCT transitions; red shifts resulting from Pd-Pd interactions in the binuclear species are not apparent. The complexes in this work are non-emissive at 298 K, but the cationic derivatives exhibit intense luminescence at 77 K. The structured emissions of 1d and 1f in MeOH/EtOH glass (lambdamax 467-586 nm) and all cationic species in the solid state (lambdamax 493-578 nm) are assigned to intraligand excited states. Complexes le-5e display dual emissions in MeOH/EtOH glass at 77 K, and the broad structureless bands at lambdamax 626-658 nm are attributed to pi-pi excimeric IL transitions. A comparison between the photophysical properties of Pd(II) and Pt(II) congeners is presented.

Reactivity of dioxoruthenium(VI) porphyrins toward amines. Synthesis and characterization of bis(arylamine)ruthenium(II), bis(arylamido)- and bis(diphenylamido)ruthenium(IV), and oxo(tert-butylimido)ruthenium(VI) porphyrins

Reactions of dioxoruthenium(VI) porphyrins, [Ru(VI)O2(Por)], with p-chloroaniline, trimethylamine, tert-butylamine, p-nitroaniline, and diphenylamine afforded bis(amine)ruthenium(II) porphyrins, [Ru(II)(Por)(L)2] (L-p-ClC6H4NH2, Me3N, Por=TTP, 4-Cl-TPP; L=tBuNH2, Por = TPP, 3,4,5-MeO-TPP, TTP, 4-Cl-TPP, 3,5-Cl-TPP) and bis(amido)ruthenium(IV) porphyrins, [Ru(IV)(Por)(X)2] (X=p-NO2C6H4NH, Por=TTP, 4-Cl-TPP; X = Ph2N, Por = 3,4,5-MeO-TPP, 3,5-Cl-TPP), respectively. Oxidative deprotonation of [Ru(II)(Por)(NH2-p-C6H4Cl)2] in chloroform by air generated bis(arylamido)ruthenium(IV) porphyrins, [RuIV(Por)(NH-p-C6H4Cl)2] (Por=TTP. 4-Cl-TPP). Oxidation of [RuII(Por)-(NH2tBu)2] by bromine in dichloromethane in the presence of tert-butylamine and traces of water produced oxo(imido)ruthenium(VI) porphyrins, [RuVI-O(Por)(NtBu)] (Por=TPP, 3,4,5-MeO-TPP, TTP, 4-Cl-TPP, 3,5-Cl-TPP). These new classes of ruthenium complexes were characterized by 1H NMR, IR, and UV/visible spectroscopy, mass spectrometry, and elemental analysis. The structure of [Ru(IV)(TTP)(NH-p-C6H4Cl)2 . CH2Cl2 was determined by X-ray crystallography. The Ru-N bond length and the Ru-N-C angle of the Ru-NHAr moiety are 1.956(7) A and 135.8(6) degrees, respectively.

The saturation characteristics of glucose transport in bovine retinal pigment epithelium

PURPOSE

To study the saturation characteristics of the glucose transport across the bovine retinal pigment epithelium(RPE).

METHODS

The bovine RPE preparations were munted with a modified Ussing chamber. The L-[3H]-glucose and 3-O-methyl-D-[14C]-glucose fluxes across the RPE from the choroid to retina were studied at different glucose concentrations.

RESULTS

The glucose transport was found to be stereospecific, with 3-O-methyl-D-glucose (MDG) being transported about three times faster than L-glucose. The glucose transport showed typical saturation characteristics in Michaelis-Menten fashion. The Vmax and the Km of corrected MDG were 2452 nmol cm-2h-1 and 30.8 mM respectively. It was shown that the glucose transport system was saturated at 61.6 mM.

CONCLUSIONS

The saturation characteristics of the corrected MDG flux suggested that the capacity of glucose transport through the bovine RPE is immense.