Multilineage cells from human adipose tissue: implications for cell-based therapies

Future cell-based therapies such as tissue engineering will benefit from a source of autologous pluripotent stem cells. For mesodermal tissue engineering, one such source of cells is the bone marrow stroma. The bone marrow compartment contains several cell populations, including mesenchymal stem cells (MSCs) that are capable of differentiating into adipogenic, osteogenic, chondrogenic, and myogenic cells. However, autologous bone marrow procurement has potential limitations. An alternate source of autologous adult stem cells that is obtainable in large quantities, under local anesthesia, with minimal discomfort would be advantageous. In this study, we determined if a population of stem cells could be isolated from human adipose tissue. Human adipose tissue, obtained by suction-assisted lipectomy (i.e., liposuction), was processed to obtain a fibroblast-like population of cells or a processed lipoaspirate (PLA). These PLA cells can be maintained in vitro for extended periods with stable population doubling and low levels of senescence. Immunofluorescence and flow cytometry show that the majority of PLA cells are of mesodermal or mesenchymal origin with low levels of contaminating pericytes, endothelial cells, and smooth muscle cells. Finally, PLA cells differentiate in vitro into adipogenic, chondrogenic, myogenic, and osteogenic cells in the presence of lineage-specific induction factors. In conclusion, the data support the hypothesis that a human lipoaspirate contains multipotent cells and may represent an alternative stem cell source to bone marrow-derived MSCs.

Calorie restriction induces mitochondrial biogenesis and bioenergetic efficiency

Age-related accumulation of cellular damage and death has been linked to oxidative stress. Calorie restriction (CR) is the most robust, nongenetic intervention that increases lifespan and reduces the rate of aging in a variety of species. Mechanisms responsible for the antiaging effects of CR remain uncertain, but reduction of oxidative stress within mitochondria remains a major focus of research. CR is hypothesized to decrease mitochondrial electron flow and proton leaks to attenuate damage caused by reactive oxygen species. We have focused our research on a related, but different, antiaging mechanism of CR. Specifically, using both in vivo and in vitro analyses, we report that CR reduces oxidative stress at the same time that it stimulates the proliferation of mitochondria through a peroxisome proliferation-activated receptor coactivator 1 alpha signaling pathway. Moreover, mitochondria under CR conditions show less oxygen consumption, reduce membrane potential, and generate less reactive oxygen species than controls, but remarkably they are able to maintain their critical ATP production. In effect, CR can induce a peroxisome proliferation-activated receptor coactivator 1 alpha-dependent increase in mitochondria capable of efficient and balanced bioenergetics to reduce oxidative stress and attenuate age-dependent endogenous oxidative damage.

Heterogeneity of kinase inhibitor resistance mechanisms in GIST

Most GIST patients develop clinical resistance to KIT/PDGFRA tyrosine kinase inhibitors (TKI). However, it is unclear whether clinical resistance results from single or multiple molecular mechanisms in each patient. KIT and PDGFRA mutations were evaluated in 53 GIST metastases obtained from 14 patients who underwent surgical debulking after progression on imatinib or sunitinib. To interrogate possible resistance mechanisms across a broad biological spectrum of GISTs, inter- and intra-lesional heterogeneity of molecular drug-resistance mechanisms were evaluated in the following: conventional KIT (CD117)-positive GISTs with KIT mutations in exon 9, 11 or 13; KIT-negative GISTs; GISTs with unusual morphology; and KIT/PDGFRA wild-type GISTs. Genomic KIT and PDGFRA mutations were characterized systematically, using complementary techniques including D-HPLC for KIT exons 9, 11-18 and PDGFRA exons 12, 14, 18, and mutation-specific PCR (V654A, D820G, N822K, Y823D). Primary KIT oncogenic mutations were found in 11/14 patients (79%). Of these, 9/11 (83%), had secondary drug-resistant KIT mutations, including six (67%) with two to five different secondary mutations in separate metastases, and three (34%) with two secondary KIT mutations in the same metastasis. The secondary mutations clustered in the KIT ATP binding pocket and kinase catalytic regions. FISH analyses revealed KIT amplicons in 2/10 metastases lacking secondary KIT mutations. This study demonstrates extensive intra- and inter-lesional heterogeneity of resistance mutations and gene amplification in patients with clinically progressing GIST. KIT kinase resistance mutations were not found in KIT/PDGFRA wild-type GISTs or in KIT-mutant GISTs showing unusual morphology and/or loss of KIT expression by IHC, indicating that resistance mechanisms are fundamentally different in these tumours. Our observations underscore the heterogeneity of clinical TKI resistance, and highlight the therapeutic challenges involved in salvaging patients after clinical progression on TKI monotherapies.

Fetal programming of skeletal muscle development in ruminant animals

Enhancing skeletal muscle growth is crucial for animal agriculture because skeletal muscle provides meat for human consumption. An increasing body of evidence shows that the level of maternal nutrition alters fetal skeletal muscle development, with long-term effects on offspring growth and performance. Fetal skeletal muscle development mainly involves myogenesis (i.e., muscle cell development), but also involves adipogenesis (i.e., adipocyte development) and fibrogenesis (i.e., fibroblast development). These tissues in fetal muscle are mainly derived from mesenchymal stem cells (MSC). Shifting the commitment of MSC from myogenesis to adipogenesis increases intramuscular fat (i.e., marbling), improving the quality grade of meats. Strong experimental evidence indicates that Wingless and Int (Wnt)/beta-catenin signaling regulates MSC differentiation. Upregulation of Wnt/beta-catenin promotes myogenesis, and downregulation enhances adipogenesis. A lack of nutrients in early to midgestation reduces the formation of secondary muscle fibers in ruminant animals. Nutrient deficiency during mid- to late gestation decreases the number of intramuscular adipocytes and muscle fiber sizes. Knowledge of this regulatory mechanism will allow the development of strategies to enhance muscle growth and marbling in offspring, especially in the setting of nutrient deficiency.

Association of Grb2, Gads, and phospholipase C-gamma 1 with phosphorylated LAT tyrosine residues. Effect of LAT tyrosine mutations on T cell angigen receptor-mediated signaling

The linker for activation of T cells (LAT) is a critical adaptor molecule required for T cell antigen receptor (TCR)-mediated signaling and thymocyte development. Upon T cell activation, LAT becomes highly phosphorylated on tyrosine residues, and Grb2, Gads, and phospholipase C (PLC)-gamma1 bind LAT via Src homology-2 domains. In LAT-deficient mutant Jurkat cells, TCR engagement fails to induce ERK activation, Ca(2+) flux, and activation of AP-1 and NF-AT. We mapped the tyrosine residues in LAT responsible for interaction with these specific signaling molecules by expressing LAT mutants with tyrosine to phenylalanine mutations in LAT-deficient cells. Our results showed that three distal tyrosines, Tyr(171), Tyr(191), and Tyr(226), are responsible for Grb2-binding; Tyr(171), and Tyr(191), but not Tyr(226), are necessary for Gads binding. Mutation of Tyr(132) alone abolished PLC-gamma1 binding. Mutation of all three distal tyrosines also abolished PLC-gamma1 binding, suggesting there might be multiple binding sites for PLC-gamma1. Mutation of Tyr(132) affected calcium flux and blocked Erk and NF-AT activation. Since Grb2 binding is not affected by this mutation, these results strongly suggest that PLC-gamma activation regulates Ras activation in these cells. Mutation of individual Grb2 binding sites had no functional effect, but mutation of two or three of these sites, in combination, also affected Erk and NF-AT activation.

Periostin promotes invasiveness and resistance of pancreatic cancer cells to hypoxia-induced cell death: role of the beta4 integrin and the PI3k pathway

Pancreatic ductal adenocarcinoma is a devastating disease, characterized by a rapid progression and poor treatment response. Using gene expression profiling of pancreatic cancer tissues, we previously identified periostin as a potential diagnostic and therapeutic target. In this study, we report the overexpression of periostin in a larger set of pancreatic cancer tissues and show that although the periostin transcript is exclusively expressed in tumour cells, the protein product is only detected in the extracellular matrix adjacent to cancer cells. Using an enzyme-linked immunosorbent assay (ELISA) assay, we show significantly increased levels of periostin in the sera of pancreatic cancer patients compared to non-cancer controls. We demonstrate that periostin promotes the invasiveness of tumour cells by increasing the motility of cells without inducing expression of proteases, and enhances the survival of tumour cells exposed to hypoxic conditions. At the molecular level, we provide evidence that the alpha(6)beta(4) integrin complex acts as the cell receptor of periostin in pancreatic cancer cells and that interaction promotes phosphorylation of focal adhesion kinase (FAK) and protein kinase B (AKT) though activation of the PI3 kinase pathway, but not the RAS/MEK/ERK pathway. These findings suggest an important role of periostin in pancreatic cancer and provide a rationale to study periostin for diagnostic and therapeutic applications.

Functional association of Nmi with Stat5 and Stat1 in IL-2- and IFNgamma-mediated signaling

Using the coiled-coil region of Stat5b as the bait in a yeast two-hybrid screen, we identified the association of Nmi, a protein of unknown function previously reported as an N-Myc interactor. We further show that Nmi interacts with all STATs except Stat2. We evaluated two cytokine systems, IL-2 and IFNgamma, and demonstrate that Nmi augments STAT-mediated transcription in response to these cytokines. Interestingly, Nmi lacks an intrinsic transcriptional activation domain; instead, Nmi enhances the association of CBP/p300 coactivator proteins with Stat1 and Stat5, and together with CBP/p300 can augment IL-2- and IFNgamma-dependent transcription. Therefore, our data not only reveal that Nmi can potentiate STAT-dependent transcription, but also suggest that it can augment coactivator protein recruitment to at least some members of a group of sequence-specific transcription factors.

Release of mechanical tension triggers apoptosis of human fibroblasts in a model of regressing granulation tissue

In an in vitro model of granulation tissue, early passage human diploid fibroblasts under mechanical tension showed little or no apoptosis. Release of mechanical tension triggered an apoptotic response that occurred within 3-6 h and reached a plateau by 24 h. The percentage of apoptotic cells (approximately 15%) remained constant up to 7 days, and after 3 days, total cell number declined. Identification of mechanical unloading as a stimulus for apoptosis, without application of pharmacologic or genetic intervention, is a novel observation that permits us to model similar events that occur during wound healing. Studies on the mechanism regulating apoptosis under these conditions established that the apoptotic response does not require differentiation of cells into myofibroblasts but is governed by a combination of mechanical tension and growth factors in the collagen matrix.

Neuroanatomic correlates of stroke-related myocardial injury

BACKGROUND

Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood.

OBJECTIVE

To identify regions of brain infarction associated with myocardial injury using a method free of the bias of an a priori hypothesis as to any specific location.

METHODS

Of 738 consecutive patients with acute ischemic stroke, the authors identified 50 patients in whom serum cardiac troponin T (cTnT) elevation occurred in the absence of any apparent cause within 3 days of symptom onset. Fifty randomly selected, age- and sex-matched patients with ischemic stroke without cTnT elevation served as controls. Diffusion-weighted images with outlines of infarction were co-registered to a template, averaged, and then subtracted to find voxels that differed between the two groups. Voxel-wise p values were determined using a nonparametric permutation test to identify specific regions of infarction that were associated with cTnT elevation.

RESULTS

The study groups were well balanced with respect to stroke risk factors, history of coronary artery disease, infarction volume, and frequency of right and left middle cerebral artery territory involvement. Brain regions that were a priori associated with cTnT elevation included the right posterior, superior, and medial insula and the right inferior parietal lobule. Among patients with right middle cerebral artery infarction, the insular cluster was involved in 88% of patients with and 33% without cTnT elevation (odds ratio: 15.00; 95% CI: 2.65 to 84.79).

CONCLUSIONS

Infarctions in specific brain regions including the right insula are associated with elevated serum cardiac troponin T level indicative of myocardial injury.

In vitro generation of human cytotoxic T lymphocytes specific for peptides derived from prostate-specific antigen

BACKGROUND

Protein antigens are presented to cytotoxic T lymphocytes as small peptides (approximately 9-10 amino acids long) bound to class I molecules of the major histocompatibility complex. The identification of tumor-associated antigens and specific peptide epitopes (i.e., antigenic determinants) may be useful in the development of anticancer vaccines. The generation of a cytotoxic T-cell response to one peptide epitope (amino acids 146-154) of human prostate-specific antigen (PSA) has been reported.

PURPOSE

Our aim was to identify novel PSA peptides capable of eliciting specific cytotoxic T-cell responses.

METHODS

Candidate peptides were identified on the basis of the following criteria: 1) they contained consensus amino acid motifs for binding to HLA-A2, which is the most common type of class I molecule; 2) they lacked strong homology with PSA-related kallikrein proteins; and 3) they were capable of stabilizing HLA-A2 class I molecules on the surface of human T2 (transport deletion mutant) cells, which are defective in antigen presentation. T-cell lines capable of killing (i.e., lysing) T2 target cells that had been pulsed with specific PSA peptides were generated from three different males (two disease-free individuals and one patient with prostate cancer) by incubating peripheral blood mononuclear cells with the peptides and interleukin 2. Specific cell lysis was monitored by the release of radioactivity from target cells that had been labeled with [111In]oxyquinoline.

RESULTS

Two novel PSA peptides capable of eliciting cytotoxic T-cell responses were identified; these peptides were designated PSA-1 (amino acids 41-150) and PSA-3 (amino acids 154-163). Four different cytotoxic T-cell lines were generated in response to these peptides-three against PSA-3 and one against PSA-1. Specific lysis of peptide-pulsed T2 cells by the T-cell lines was blocked by the addition of a monoclonal antibody directed against class I molecules. The T-cell lines were also capable of lysing PSA-positive, HLA-A2-positive LNCaP cells (human prostate carcinoma cells). The specificity of LNCaP cell lysis was shown by the following: 1) the inability of added human K562 (chronic myelogenous leukemia) cells to inhibit it, 2) the ability of added anti-HLA-A2 antibodies to block it, and 3) the inability of the T-cell lines to induce substantial lysis of PSA-negative, HLA-A2-positive human cancer cells.

IMPLICATIONS

Our studies form a rational basis for the use of PSA peptides or recombinant vectors encoding PSA in the development of anticancer vaccine immunotherapy protocols for patients with prostate cancer.

Overexpression of glucose transporters in rat mesangial cells cultured in a normal glucose milieu mimics the diabetic phenotype

An environment of high glucose concentration stimulates the synthesis of extracellular matrix (ECM) in mesangial cell (MC) cultures. This may result from a similar increase in intracellular glucose concentration. We theorized that increased uptake, rather than glucose concentration per se is the major determinant of exaggerated ECM formation. To test this, we compared the effects of 35 mM glucose on ECM synthesis in normal MCs with those of 8 mM glucose in the same cells overexpressing the glucose transporter GLUT1 (MCGT1). Increasing medium glucose from 8 to 35 mM caused normal MCs to increase total collagen synthesis and catabolism, with a net 81-90% increase in accumulation. MCs transduced with the human GLUT1 gene (MCGT1) grown in 8 mM glucose had a 10-fold greater GLUT1 protein expression and a 1.9, 2.1, and 2.5-fold increase in cell myo-inositol, lactate production, and cell sorbitol content, respectively, as compared to control MCs transduced with bacterial beta-galactosidase (MCLacZ). MCGT1 also demonstrated increased glucose uptake (5-fold) and increased net utilization (43-fold), and greater synthesis of individual ECM components than MCLacZ. In addition, total collagen synthesis and catabolism were also enhanced with a net collagen accumulation 111-118% greater than controls. Thus, glucose transport activity is an important modulator of ECM formation by MCs; the presence of high extracellular glucose concentrations is not necessarily required for the stimulation of matrix synthesis.

Characterization of antioxidants present in hawthorn fruits

Hawthorn fruit extract has been shown to have many health benefits including being cardiovascular protective, hypotensive and hypocholesterolemic. The present study was carried out to characterize further the antioxidants of hawthorn fruit and their effect on the oxidation of human low density lipoprotein (LDL) and alpha-tocopherol. The dry hawthorn fruit was extracted successively with ether, ethyl acetate, butanol and water. The ethyl acetate fraction was only effective in inhibition of Cu(+2)-mediated LDL oxidation. The column chromatographic separation led to isolation of eight pure compounds; namely, ursolic acid, hyperoside, isoquercitrin, epicatechin, chlorogenic acid, quercetin, rutin and protocatechuic acid. All of these phenolic compounds, except ursolic acid, were protective to human LDL from Cu(+2)-mediated LDL oxidation. They were also effective in preventing the peroxy free radical-induced oxidation of alpha-tocopherol in human LDL. The inhibitory effect of these compounds on oxidation of LDL and alpha-tocopherol was dose-dependent at concentrations ranging from 5 to 40 µM. In addition, supplementation of 2% hawthorn fruit powder significantly elevated serum alpha-tocopherol by 18-20% in rats fed a 30% polyunsaturated canola oil diet, as compared with the control. The present results suggest that part of the mechanism for cardiovascular protective effects of hawthorn fruit might also involve the direct protection to human LDL from oxidation or indirect protection via maintaining the concentration of alpha-tocopherol in human LDL.

Surface and wire EMG crosstalk in neighbouring muscles

Surface and wire myoelectric activity of the medial gastrocnemius (MG), lateral gastrocnemius (LG) and tibialis anterior (TA) of the cat were recorded during supramaximal stimulation applied via their nerves before and after the muscle nerve to the LG and TA were cut in order to determine the amount of EMG crosstalk amongst neighbouring muscles. It was shown that the peak-to-peak (p-p) amplitude and mean absolute value (MAV) of crosstalk M waves recorded from the LG and TA after their nerve was cut did not exceed 5% of their maximal value for surface electrodes and 2.5% of their maximal value for wire electrodes. EMG crosstalk values were similar in terms of peak to peak and MAV. Surface EMG crosstalk values were significantly higher in preparations in which a substantial amount of subcutaneous fat covered the muscles, being 20 (± 16.6) % MAV and 16 (± 12) % p-p. During increasing force contraction (accomplished by orderly recruitment of motor units) from 10-100% of the maximal force of the MG the corresponding crosstalk in the LG and TA increased linearly with the EMG of the MG. It is concluded that the crosstalk problem in surface recording is negligible for most biomechanical studies in which standard EMG recording protocol is employed, yet a warning is issued against the indiscriminate recording of surface EMG from muscles covered by adipose tissue.

Fibronectin degradation in chronic wounds depends on the relative levels of elastase, alpha1-proteinase inhibitor, and alpha2-macroglobulin

The goal of our studies was to learn about the mechanism of fibronectin degradation in chronic ulcers. We found that the appearance of fibronectin fragments in chronic ulcer wound fluid correlated with elevated levels of elastase and cleavage of the proteinase inhibitors alpha2-macroglobulin (alpha2-M) and alpha 1-proteinase inhibitor (alpha1-P1). Some wound fluid samples retained the capacity to degrade fibronectin in vitro. Degradation of fibronectin by these samples was blocked by specific inhibitors of neutrophil elastase but not by inhibitors of metalloproteinases. Addition of human neutrophil elastase to mastectomy fluid, an acute wound fluid, resulted in formation of alpha1-PI and alpha2-M complexes and cleavage products resembling those observed in chronic wound fluid. Moreover, degradation of fibronectin and processing of matrix metalloproteinase MMP-9 occurred under these conditions. Taken together, our findings suggest that elevated levels of neutrophil elastase are responsible for fibronectin degradation in the chronic wound environment.

Mutations in the gamma-actin gene (ACTG1) are associated with dominant progressive deafness (DFNA20/26)

Age-related hearing loss (presbycusis) is a significant problem in the population. The genetic contribution to age-related hearing loss is estimated to be 40%-50%. Gene mutations that cause nonsyndromic progressive hearing loss with early onset may provide insight into the etiology of presbycusis. We have identified four families segregating an autosomal dominant, progressive, sensorineural hearing loss phenotype that has been linked to chromosome 17q25.3. The critical interval containing the causative gene was narrowed to approximately 2 million bp between markers D17S914 and D17S668. Cochlear-expressed genes were sequenced in affected family members. Sequence analysis of the gamma-actin gene (ACTG1) revealed missense mutations in highly conserved actin domains in all four families. These mutations change amino acids that are conserved in all actins, from protozoa to mammals, and were not found in >100 chromosomes from normal hearing individuals. Much of the specialized ultrastructural organization of the cells in the cochlea is based on the actin cytoskeleton. Many of the mutations known to cause either syndromic or nonsyndromic deafness occur in genes that interact with actin (e.g., the myosins, espin, and harmonin). The mutations we have identified are in various binding domains of actin and are predicted to mildly interfere with bundling, gelation, polymerization, or myosin movement and may cause hearing loss by hindering the repair or stability of cochlear cell structures damaged by noise or aging. This is the first description of a mutation in cytoskeletal, or nonmuscle, actin.

Association between tPA therapy and raised early matrix metalloproteinase-9 in acute stroke

BACKGROUND

Matrix metalloproteinase-9 (MMP9) is expressed in acute ischemic stroke and up-regulated by tissue plasminogen activator (tPA) in animal models. The authors investigated plasma MMP9 and its endogenous inhibitor, tissue inhibitor of metalloproteinase (TIMP1), in tPA-treated and -untreated stroke patients.

METHODS

Nonstroke control subjects and consecutive ischemic stroke patients presenting within 8 hours of onset were enrolled. Blood was sampled within 8 hours and at 24 hours, 2 to 5 days and 4 to 6 weeks. MMP9 and TIMP1 were analyzed by ELISA and gel zymography.

RESULTS

Fifty-two cases (26 tPA treated, 26 tPA untreated) and 27 nonstroke control subjects were enrolled. Hyperacute MMP9 was elevated in tPA-treated vs tPA-untreated patients (medians 43 vs 28 ng/mL; p = 0.01). tPA therapy independently predicted hyperacute MMP9 after adjustment for stroke severity, volume, and hemorrhagic transformation (p = 0.01). There was a trend toward lower hyperacute TIMP1 levels in tPA-treated vs tPA-untreated patients (p = 0.06). Hyperacute MMP9 was correlated to poor 3-month modified Rankin Scale outcome (r = 0.58, p = 0.0005).

CONCLUSION

Tissue plasminogen activator independently predicted plasma matrix metalloproteinase-9 (MMP9) in the first 8 hours after human ischemic stroke. As MMP9 may be an important mediator of hemorrhagic transformation, alternative thrombolytic agents or therapeutic MMP9 inhibition may increase the safety profile of acute stroke thrombolysis.

In vitro characterization and pharmacokinetics of dapagliflozin (BMS-512148), a potent sodium-glucose cotransporter type II inhibitor, in animals and humans

(2S,3R,4R,5S,6R)-2-(3-(4-Ethoxybenzyl)-4-chlorophenyl)-6-hydroxymethyl-tetrahydro-2H-pyran-3,4,5-triol (dapagliflozin; BMS-512148) is a potent sodium-glucose cotransporter type II inhibitor in animals and humans and is currently under development for the treatment of type 2 diabetes. The preclinical characterization of dapagliflozin, to allow compound selection and prediction of pharmacological and dispositional behavior in the clinic, involved Caco-2 cell permeability studies, cytochrome P450 (P450) inhibition and induction studies, P450 reaction phenotyping, metabolite identification in hepatocytes, and pharmacokinetics in rats, dogs, and monkeys. Dapagliflozin was found to have good permeability across Caco-2 cell membranes. It was found to be a substrate for P-glycoprotein (P-gp) but not a significant P-gp inhibitor. Dapagliflozin was not found to be an inhibitor or an inducer of human P450 enzymes. The in vitro metabolic profiles of dapagliflozin after incubation with hepatocytes from mice, rats, dogs, monkeys, and humans were qualitatively similar. Rat hepatocyte incubations showed the highest turnover, and dapagliflozin was most stable in human hepatocytes. Prominent in vitro metabolic pathways observed were glucuronidation, hydroxylation, and O-deethylation. Pharmacokinetic parameters for dapagliflozin in preclinical species revealed a compound with adequate oral exposure, clearance, and elimination half-life, consistent with the potential for single daily dosing in humans. The pharmacokinetics in humans after a single dose of 50 mg of [(14)C]dapagliflozin showed good exposure, low clearance, adequate half-life, and no metabolites with significant pharmacological activity or toxicological concern.

Plant polyphenols: biologically active compounds or non-selective binders to protein?

Twenty phenolic compounds, representatives of proanthocyanidins and gallic acid/hexahydroxyldiphenic acid esters of glucose, have been assessed for their ability to inhibit binding of specific radioligands to 16 receptors. The receptors utilized were alpha 1-, alpha 2- and beta-adrenoceptors, adenosine 1, dopamine 1 and 2, muscarinic, Ca2+ channel, sulphonylureas, 5HT1, 5HT1A, 5HT2, histamine 1, benzodiazepine, opiate and Na+/K/ATPase. These phenolic compounds failed to inhibit ligands binding to 10 of the receptors under the test conditions. The most susceptible receptors to phenolic binding were beta-adrenergic, 5HT1 and opiate. Some of the compounds tested showed selectivity for a single or for two receptors. The inhibition of binding of radioligands to receptors by the phenolic compounds cannot be explained solely in terms of phenolic-protein binding. The results indicate that the removal of tannins from plant extracts prior to screening for receptor activities may result in missing biologically active compounds with specificity of action.

Functional characterization of transcription regulators that interact with the electrophile response element

The electrophile response element (EpRE), also referred to as the antioxidant responsive element (ARE), is found in the 5'-regulatory region of a number of genes encoding phase II, drug-metabolizing enzymes. Gene knockout studies have demonstrated the primary regulatory role that an Nrf2:Maf dimer plays by binding to nucleotides within the EpRE consensus sequence. Current models of transcription regulation have also shown the involvement of higher-order transcriptional coactivators, proteins that nucleate around DNA sequence-specific transcription factors, enhancing transcription of the target gene by interacting with components of the basal transcriptional apparatus and by enabling chromatin remodeling. Here, we hypothesized that multiple transcriptional regulators, including: (i) a primary Nrf2-Maf heterodimer, (ii) a proposed secondary, EpRE-specific, p160 family coactivator, ARE-binding protein-1, and (iii) a tertiary coactivator, CBP/p300, nucleate to form a complex at the EpRE that regulates transcription of the dependent gene. To test this hypothesis, we constructed a HepG2 cell line which contains a stably integrated green fluorescent protein (GFP) gene; its inducible expression is regulated by a synthetic TK promoter containing a linked EpRE. To identify the involvement of specific, primary and higher-order transcriptional regulators in the EpRE-mediated regulation of the GFP reporter gene, we microinjected antibodies directed against specific transcription factors into the HepG2/GFP cells and determined their effect upon tBHQ-induced expression of the GFP gene. The results demonstrate that microinjected antibodies directed against Nrf2, MafK, CBP and p300 could each, individually, significantly inhibit tBHQ-induced GFP expression. This directly demonstrates the role that the tertiary regulators, CBP or p300, play in mediating EpRE activation of phase II genes, and also implicates the involvement of secondary, p160 family coactivators. Moreover, we found that the same anti-MafK antibody that blocked induction of the EpRE-regulated GFP gene completely ablated the gel-shift complex that we hypothesize contains an Nrf2:Maf dimer, ARE-binding protein-1, and CBP or p300.

MR imaging of pituitary morphology in idiopathic intracranial hypertension

The aim of this study was to investigate the morphologic changes of the pituitary gland in patients with the clinical diagnosis of idiopathic intracranial hypertension (IIH). Qualitative and quantitative analyses of pituitary morphology were performed in normal subjects (n = 23), patients with the clinical diagnosis of IIH (n = 40), and patients with acute increased intracranial pressure (AICP; n = 37) caused by acute head trauma. The loss of pituitary height (concavity) on the sagittal T1-weighted image was classified into five categories: I = normal, II = superior concavity that was mild (<(1/3) the height of the sella), III = moderate (between (1/3) and (2/3) concavity of height of sella), IV = severe (>(2/3) concavity of height of sella), and V = empty sella. The area ratio of pituitary gland to sella turcica measured in the midsagittal plane was quantified. Clinical records were retrospectively reviewed to correlate with magnetic resonance (MR) findings. Using moderate concavity (>(1/3)) as the minimum criterion for abnormality, IIH patients had an 85% incidence of morphologic changes with 80% sensitivity and 92% specificity. Empty sella (almost complete concavity of the sella) was found in only 2.5% of patients with IIH. Quantitative analysis of the pituitary gland/sella turcica area ratio showed a significant decrease in patients with IIH (P < 0.0001) but no significant difference between the normal subjects and AICP patients. A posterior deviation of the pituitary stalk was seen in 43% of patients. No enlargement of the ventricles or sulcal effacement was seen in IIH patients. Routine brain MR examination of patients with IIH frequently shows morphologic changes of the pituitary gland ranging from various degrees of concavity to (rarely) the extreme case of an empty sella. The etiology is unknown and may be related to the severity and duration of elevated CSF pressure. Such findings may be useful to facilitate the diagnosis of IIH, particularly in patients with equivocal clinical findings or when IIH is not suspected. J. Magn. Reson. Imaging 2000;12:808-813.

Psychological adjustment among left-behind children in rural China: the role of parental migration and parent-child communication

BACKGROUND

Left-behind children refer to those rural children who are under 18 years of age and are left at home when both or one of their parents migrate to urban area for work. Recent findings showed that left-behind children were disadvantaged by developmental, emotional and social problems.

METHOD

A sample of 1165 rural children and adolescents were recruited to examine the characteristics of left-behind children and explore the differences in psychological adjustment (including satisfaction, loneliness and happiness) by patterns of parental migration (i.e. no parent migrating, one parent migrating or two parents migrating) and the level of parent-child communication in rural China.

RESULTS

(1) Compared with children with one parent migrating, children with two parents migrating were separated from their parents at younger ages, for longer periods, and saw their migrant parents less frequently. (2) Children with two parents migrating reported the lowest level of satisfaction among the three groups of rural children. Both groups of children with one or two parents migrating experienced more loneliness compared with children with no parent migrating. There were no significant differences in school satisfaction and happiness among the three groups. (3) The children who reported a higher level of parent-child communication also reported a higher level of life and school satisfaction and happiness, and no differences in loneliness were found by levels of parent-child communication.

CONCLUSIONS

These results indicate that loneliness was the most common and important experience of left-behind children. Parent-child communication is important for the development of all rural children, including those who were left behind by their migrant parents.

Oral absorption and bioavailability of tea catechins

The absorption characteristics and oral bioavailability of three tea catechins, namely (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), were assessed in this study. Male Sprague Dawley rats (210-230 g) received either an intravenous (i.v. 50 mg/kg) or oral (5000 mg/kg) dose of decaffeinated catechin-fraction containing EC (5%), EGCG (50%), and ECG (13%). Concentrations of the compounds in plasma, urine, and feces were measured using HPLC. A non-compartmental approach was employed for pharmacokinetic analysis. Results indicated that maximum plasma concentrations for the catechins (15-112 micrograms/ml) were achieved at 2 h post-oral dosing and the apparent volume of distribution (Vd/F) ranged from 30 to 63 l/kg. Absolute bioavailability (F) of EC, EGCG, and ECG was assessed to be 0.39, 0.14, and 0.06, respectively. Estimates of terminal elimination half-life (t1/2, lambda z) of the catechins after oral dosing were 451-479 min and were 1.4-10 fold longer than those observed for the i.v. dosing. The discrepancy in terminal elimination and low rate and extent of absorption indicated the possibility of flip-flop kinetics. Respective urinary recoveries were 0.17-4.72% and 2.11-14.2% after oral and i.v. dosing. In conclusion, the low systemic availability of tea catechins observed could be a result of slow absorption, high first pass effect, and wide tissue distribution.

Triterpene antioxidants from ganoderma lucidum

Ganoderma lucidum was studied for its antioxidative activity by bioassay guided isolation in conjunction with in vitro tests. The powdered crude drug was treated with boiling water and the aqueous extract (Ex1) was further separated to obtain terpene and polysaccharide fractions. The two fractions and Ex1 were screened for their antioxidative effect against pyrogallol induced erythrocyte membrane oxidation and Fe (II)-ascorbic acid induced lipid peroxidation. All tested samples showed antioxidative activities in a dose dependent manner and the terpene fraction was found to possess the highest effect compared with the others. Chemical isolation of the terpene fraction resulted in the detection of ganoderic acids A, B, C and D, lucidenic acid B and ganodermanontriol as major ingredients.

An endogenous regulator of inflammation, resolvin E1, modulates osteoclast differentiation and bone resorption

BACKGROUND AND PURPOSE

The inflammation-resolving lipid mediator resolvin E1 (RvE1) effectively stops inflammation-induced bone loss in vivo in experimental periodontitis. It was of interest to determine whether RvE1 has direct actions on osteoclast (OC) development and bone resorption.

EXPERIMENTAL APPROACH

Primary OC cultures derived from mouse bone marrow were treated with RvE1 and analysed for OC differentiation, cell survival and bone substrate resorption. Receptor binding was measured using radiolabelled RvE1. Nuclear factor (NF)-kappaB activation and Akt phosphorylation were determined with western blotting. Lipid mediator production was assessed with liquid chromatography tandem mass spectrometry.

KEY RESULTS

OC growth and resorption pit formation were markedly decreased in the presence of RvE1. OC differentiation was inhibited by RvE1 as demonstrated by decreased number of multinuclear OC, a delay in the time course of OC development and attenuation of receptor activator of NF-kappaB ligand-induced nuclear translocation of the p50 subunit of NF-kappaB. OC survival and apoptosis were not altered by RvE1. Messenger RNA for both receptors of RvE1, ChemR23 and BLT(1) is expressed in OC cultures. Leukotriene B(4) (LTB(4)) competed with [(3)H]RvE1 binding on OC cell membrane preparations, and the LTB(4) antagonist U75302 prevented RvE1 inhibition of OC growth, indicating that BLT(1) mediates RvE1 actions on OC. Primary OC synthesized the RvE1 precursor 18R-hydroxy-eicosapentaenoic acid and LTB(4). Co-incubation of OC with peripheral blood neutrophils resulted in transcellular RvE1 biosynthesis.

CONCLUSIONS AND IMPLICATIONS

These results indicate that RvE1 inhibits OC growth and bone resorption by interfering with OC differentiation. The bone-sparing actions of RvE1 are in addition to inflammation resolution, a direct action in bone remodelling.