Correlation of magnesium intake with metabolic parameters, depression and physical activity in elderly type 2 diabetes patients: a cross-sectional study

BACKGROUND

Type 2 diabetes mellitus is a major global public health problem in the worldwide and is increasing in aging populations. Magnesium intake may be one of the most important factors for diabetes prevention and management. Low magnesium intake may exacerbate metabolic abnormalities. In this study, the relationships of magnesium intake with metabolic parameters, depression and physical activity in elderly patients with type 2 diabetes were investigated.

METHODS

This cross-sectional study involved 210 type 2 diabetes patients aged 65 years and above. Participants were interviewed to obtain information on lifestyle and 24-hour dietary recall. Assessment of depression was based on DSM-IV criteria. Clinical variables measured included anthropometric measurements, blood pressure, and biochemical determinations of blood and urine samples. Linear regression was applied to determine the relationships of magnesium intake with nutritional variables and metabolic parameters.

RESULTS

Among all patients, 88.6% had magnesium intake which was less than the dietary reference intake, and 37.1% had hypomagnesaemia. Metabolic syndromes and depression were associated with lower magnesium intake (p < 0.05). A positive relationship was found between magnesium intake and HDL-cholesterol (p = 0.005). Magnesium intake was inversely correlated with triglyceride, waist circumference, body fat percent and body mass index (p < 0.005). After controlling confounding factor, HDL-cholesterol was significantly higher with increasing quartile of magnesium intake (p for trend = 0005). Waist circumference, body fat percentage, and body mass index were significantly lower with increase quartile of magnesium intake (p for trend < 0.001). The odds of depression, central obesity, high body fat percentage, and high body mass index were significantly lower with increasing quartile of magnesium intake (p for trend < 0.05). In addition, magnesium intake was related to high physical activity level and demonstrated lower serum magnesium levels. Serum magnesium was not significantly associated with metabolic parameters.

CONCLUSIONS

The majority of elderly type 2 diabetes who have low magnesium intake may compound this deficiency with metabolic abnormalities and depression. Future studies should determine the effects of increased magnesium intake or magnesium supplementation on metabolic control and depression in elderly people with type 2 diabetes.

First Report of Leaf Spot on Gerbera jamesonii Caused by Corynespora cassiicola in China

Gerbera (Gerbera jamesonii Bolus ex. Hook f.) is a popular cut flower and flowering potted plant. In August 2011, a new leaf spot disease was observed on double-type Gerbera growing in outdoor ground beds in Guangzhou, Guangdong Province, China. Approximately 30% of about 20,000 Gerbera plants in the Guangzhou ground beds were affected. Leaf spots were round or irregular with grayish centers surrounded by dark brown borders and ranged from 5 to 15 mm in diameter. Leaves with multiple lesions became blighted. A fungus was isolated from the lesions and single-spore isolates plated on potato dextrose agar (PDA) produced gray, floccose colonies, which reached 65 mm on PDA after 7 days at 28°C. Conidiophores were brown or olivaceous, cylindrical, straight and unbranched, two to seven septations, and 25 to 83 × 4 to 7 μm. Conidiogenous cells were olivaceous or brown, cylindrical, and 11 to 21 × 4 to 6 μm. Conidia were borne singly or in chains of two to five, brown, cylindrical, straight to slightly curved, two to eight pseudosepta, and 30 to 90 × 5.5 to 11.5 μm (mean 70.4 × 7.3 μm), with a conspicuous hilum. These characteristics were consistent with the description of Corynespora cassiicola (Berk. & M.A. Curtis.) C.T. Wei (1). The internal transcribed spacer region (ITS) of one isolate (GenBank Accession No. JN853778) was amplified using primers ITS4 and ITS5 (3) and sequenced. A BLAST search in GenBank revealed highest similarity (99%) to sequences of C. cassiicola (AY238606.1 and FJ852715.1). Pathogenicity tests were conducted on 10 potted double-type Gerbera plants. Five wounded and five unwounded leaves on each plant were inoculated with 5-mm mycelial plugs from the periphery of 5-day-old cultures of the isolated fungus. The plugs were put on the leaf surface and secured with sterile wet cotton. Sterile PDA plugs were used as the control treatment on different leaves of the same plants that were inoculated. Plants were covered with plastic bags and incubated in a growth chamber with 12 h of light at 28°C. Necrotic lesions appeared on wounded leaves after 2 to 3 days of incubation and on unwounded leaves 5 to 7 days after incubation. Symptoms on wounded and unwounded leaves were similar to those observed in the field, whereas control leaves inoculated with sterile PDA plugs remained symptomless. C. cassiicola was consistently reisolated from these lesions. Although there are approximately 644 reported hosts of C. cassiicola (2), to our knowledge, this is the first report of C. cassiicola leaf spot on G. jamesonii. Because the disease caused damage to the foliage and affected the flowering of the plants, control measures may need to be implemented for the production of Gerbera in cut flower nurseries. References: (1) M. B. Ellis. CMI Mycol. Pap. 65:15, 1957. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 21 November 2011. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Cymbidium sinense in China

Cymbidium sinense are among the most important commercial orchids cultivated in China for flower production. In April of 2010, a leaf spot was sporadically observed on C. sinense in fields located in Guangzhou, China. Symptoms first appeared as yellow to brown, irregular-shaped lesions on the leaf margin or tip. As the infection continued on the tissues, the spot expanded and became dark brown along the margins and developed gray brown centers. At later stages, numerous epidermal acervuli developed on the lesions and mucilaginous conidial masses appeared on the lesions under moist conditions. Ten samples from tissue along the margins of lesions were collected and surface sterilized by washing in 70% ethanol for 30 s, followed by washing in 1% sodium hypochlorite for 30 s, and rinsing in sterile distilled water. These samples were plated onto potato dextrose agar (PDA) and incubated at 25°C with a 12-h alternating light and dark cycle. After 5 days, fungal colonies that grew from the tissue were subcultured onto PDA and pure cultures were obtained using the single-spore method. The fungus was identified as Colletotrichum gloeosporioides based on typical cultural characteristics and conidial morphology (1). PDA cultures were white at first and subsequently became grayish white to gray and pink to reddish brown. Conidia were straight, one-celled, hyaline, oblong, or cylindrical, slightly curved with truncate base and rounded apex and measured 14.0 to 19.5 × 4.0 to 6.0 μm. Chlamydospores, sclerotia, and a teleomorph were not found. Genomic DNA was extracted from one isolate and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1-5.8S-ITS2) was amplified using ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-CCTCCGCTTATTGATATGC-3') primers. The ITS region was further cloned and sequenced and showed 100% homology with many GenBank sequences (e.g., HQ333546.1) of C. gloeosporioides as the closest match. Pathogenicity tests were done by transferring one 4-mm-diameter disk of PDA that was colonized by the test isolates to wounds (4 × 4 mm) made with a needle in the leaves of 1-year-old C. sinense plants. Control plants received a sterile agar plug in wound. Ten inoculated plants were covered with plastic bags to maintain a high relative humidity and maintained in a greenhouse at 25 ± 2°C for 72 h. Five days after inoculation, no symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from symptomatic tissue collected from greenhouse experiments. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose on C. sinense in China. Reference: (1) B. C. Sutton. Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992.

Chromate reduction on humic acid derived from a peat soil--exploration of the activated sites on HAs for chromate removal

Humic substances are a major component of soil organic matter that influence the behavior and fate of heavy metals such as Cr(VI), a toxic and carcinogenic element. In the study, a repetitive extraction technique was used to fractionate humic acids (HAs) from a peat soil into three fractions (denoted as F1, F2, and F3), and the relative importance of O-containing aromatic and aliphatic domains in humic substances for scavenging Cr(VI) was addressed at pH 1. Spectroscopic analyses indicated that the concentrations of aromatic C and O-containing functional groups decreased with a progressive extraction as follows: F1>F2>F3. Cr(VI) removal by HA proceeded slowly, but it was enhanced when light was applied due to the production of efficient reductants, such as superoxide radical and H(2)O(2), for Cr(VI). Higher aromatic- and O-containing F1 fraction exhibited a greater efficiency for Cr(VI) reduction (with a removal rate of ca. 2.89 mmol g(-1) HA under illumination for 3 h). (13)C NMR and FTIR spectra further demonstrated that the carboxyl groups were primarily responsible for Cr(VI) reduction. This study implied the mobility and fate of Cr(VI) would be greatly inhibited in the environments containing such organic groups.

Influence of chemical compositions and molecular weights of humic acids on Cr(VI) photo-reduction

Humic acids (HA) strongly affect the fate of trace metals in soils and aquatic environments. One of the remarkable properties of HA is its ability to reduce Cr(VI), an extremely toxic anion. However, it is unclear which HA components are involved in Cr(VI) reduction and possess the photo-induced properties. In this study, an ultrafiltration technique was used to fractionate HAs into four fractions of different nominal molecular weights (M(w)): >100, 50-100, 10-50 and <10 kDa. Each HA fraction was characterized by spectroscopic analyses followed by examining Cr(VI) removal on each fraction of HA at pH 1-5. Spectroscopic results indicated that low-M(w) HA was enriched with polar and aromatic domains. These polar, including polar C in aliphatic region, and aromatic groups were the major sites for Cr(VI) reduction because they disappeared rapidly upon interaction with Cr(VI). As a result, low M(w) of HA exhibited greater efficiency of Cr(VI) reduction. Light induced the rapid transfer of electrons between chromate-phenol/carboxyl ester, or the formation of peroxide radicals or H(2)O(2) through the ready decay of peroxy radicals associated with polar substituents, explained the rapid scavenging of Cr(VI) on polar and aromatic groups of HAs under illumination.

Coexistence of exchange bias and magnetization pinning in the MnO(x)/GaMnAs system

Coexistence of exchange bias (H(E)) and magnetization (M) shift was observed in as-grown and field-annealed MnO(x)/Ga(0.95)Mn(0.05)As bilayers. It was found that H(E) initially decreases with the annealing time t(a) and then increases when t(a) > 30 min, while the M shift remains almost unchanged with t(a). X-ray photoelectron spectroscopy (XPS) analysis reveals that MnO(x) is composed of MnO and Mn(3)O(4), and the volume amount ratio of Mn(3)O(4) to MnO increases with increasing t(a). A simple model based on a uniform MnO-Mn(3)O(4) interface with constant 'pinned' uncompensated interfacial spins is proposed to account for the observed exchange-biased phenomena in the bilayers.

First Report of Myrothecium Leaf Spot of Hemionitis arifolia Caused by Myrothecium roridum in China

Hemionitis arifolia (Burm.) Moore. was grown commercially as an ornamental plant in China. In January 2010, a new foliar disease with typical leaf spot symptoms was observed on H. arifolia in Dongguan City, Guangdong Province. Approximately 10% of the plants in the Dongguan nursery were affected. Leaf spots were circular to subcircular, dark brown, with distinct concentric zones, and ranged from 10 to 20 mm in diameter. Lesions developed mostly on the lower leaves and black sporodochia with white mycelial tufts were produced mostly in older lesions under high humidity. Single-spore isolates from lesions plated on potato dextrose agar (PDA) produced white, floccose colonies and dark green-to-black sporodochia. Colonies reached 60 mm on PDA at 25°C after 14 days. Conidiophores branched repeatedly. Conidiogenous cells in whorls of two to six on ultimate branches were hyaline, cylindrical, and 13 to 20 × 1.2 to 1.8 μm. Conidia were hyaline, cylindrical, mostly with both rounded ends, occasionally one blunt end, and mean size was 6.1 (4.5 to 7.0) × 2.3 (1.8 to 3.0) μm. These characteristics were consistent with the descriptions of Myrothecium roridum Tode ex Fr. (2-4). The internal transcribed spacer regions including ITS1, ITS2, and the 5.8S rRNA of one isolate were PCR amplified and sequenced. A BLAST search in GenBank revealed highest similarity (99%) to M. roridum sequences from isolates collected from Germany (Accession Nos. AJ302001.1 and AJ301995.1). The M. roridum sequence from the Chinese isolate was submitted to GenBank (Accession No. JF343832). To confirm pathogenicity, five leaves on five H. arifolia plants were inoculated with 5-mm mycelial plugs from the periphery of 7-day-old cultures; sterile PDA plugs were used as the control treatment. Plants were covered with plastic bags and incubated in a growth chamber at 28°C. Necrotic lesions appeared 2 to 3 days after inoculation and the symptoms described above were observed after 7 days on all inoculated leaves, whereas sterile PDA plugs did not produce any leaf lesion. The pathogen was reisolated from the inoculated leaves and confirmed to be M. roridum on the basis of morphological characteristics. There are approximately 271 hosts of M. roridum (1), including many ornamental plants such as salvia (2) and garden hydrangea (3). To our knowledge, this is the first report of Myrothecium leaf spot on H. arifolia. Because the disease caused damage to the foliage and reduced the ornamental value of H. arifolia plants, control measures may need to be implemented for production of this species in ornamental nurseries. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrived from http://nt.ars-grin.gov/fungaldatabases/ , 6 February 2011. (2) J. A. Mangandi et al. Plant Dis. 91:772, 2007. (3) M. T. Mmbaga et al. Plant Dis. 94:1266, 2010. (4) M. Tulloch. Mycol. Pap. No. 130. CMI, Wallingford, UK, 1972.

Color variation in periodic Ag line arrays patterned by using electron-beam lithography

Periodic Ag line arrays with different line pitches from 500 nm to 950 nm on ITO coated glass substrates have been fabricated by using electron-beam lithography (EBL) technique for studying the color light guide in a display system. The patterned Ag line array is used as a light outcoupling and color-selection component due to the emission wavelength changed by the Ag line arrays with different periodic distances that could achieve color variation. We have demonstrated that the ITO coated glass substrates containing periodic Ag line arrays with varied line pitches can be used as a color filter in a display device. This means that with a proper metallic nanostructure layer, the red, green, and blue colors in a display system can be obtained without a traditional color filter for modern multi-applications of optoelectronic display devices.

Biocompatibility of Fe(3)O(4) nanoparticles evaluated by in vitro cytotoxicity assays using normal, glia and breast cancer cells

In order to reveal the biocompatibility of Fe(3)O(4) nanoparticles and bipolar surfactant tetramethylammonium 11-aminoundecanoate cytotoxicity tests were performed as a function of concentration from low (0.1 microg ml(-1)) to higher concentration (100 microg ml(-1)) using various human glia, human breast cancer and normal cell lines. Cytotoxicity tests for human glia (D54MG, G9T, SF126, U87, U251, U373), human breast cancer (MB157, SKBR3, T47D) and normal (H184B5F5/M10, WI-38, SVGp12) cell lines exhibited almost nontoxicity and reveal biocompatibility of Fe(3)O(4) nanoparticles in the concentration range of 0.1-10 microg ml(-1), while accountable cytotoxicity can be seen at 100 microg ml(-1). The results of our studies suggest that Fe(3)O(4) nanoparticles coated with bipolar surfactant tetramethylammonium 11-aminoundecanoate are biocompatible and promising for bio-applications such as drug delivery, magnetic resonance imaging and magnetic hyperthermia.

Emissions of inorganic and organic arsenic compounds via the leachate pathway from pretreated municipal waste materials: a landfill reactor study

The emission of arsenic (As) with leachate from mechanically biologically pretreated municipal solid waste (MBP-MSW) was quantified over one year using landfill simulation reactors. Arsenic mobilization and transformation processes were studied by simulating different environmental conditions (anoxic conditions with underlying soil or oxic/anoxic conditions). Amounts of mono-, di-, and trimethylated As in MBP-MSW prior to simulation were < 48 microg As kg(-1) and were magnified to 300-390 microg As kg(-1) under anoxic conditions, whereas methylated As was undetectable in the oxic setup. The highest leachate concentrations (up to 84 microg L(-1)) occurred during the first four weeks of manipulation. The annual Astotal release with leachates averaged 19.6, 7.6, and 4.5 microg kg(-1) under an anoxic environment with underlying soil, oxic conditions, and anoxic conditions, respectively, with 15-50% occurring as organic As. The annually released As represented 0.2-0.8% of the Astotal pool, suggesting that As mobilization from waste is a slow process. The anoxia diminished As release rates, whereas anoxic conditions with underlying soil material elevated the As mobilization, probably due to reductive dissolution of soil-derived Fe and Mn (hydr)oxides. The mass balance of methylated As in MBP-MSW and leachates before and after the treatments highlights As methylation under anoxic conditions and demethylation under oxic landfill conditions.

Current status of thalassemia in minority populations in Guangxi, China

Thalassemia is one of the most common monogenic disorders in the world. In order to develop a community-based prevention program, we screened 12,900 individuals for alpha- and beta-thalassemia in Baise City, Guangxi, China, with hematological methods and molecular assays. We found that the frequency of carriers in this area for alpha-thalassemia is 15%. Beta-thalassemia carriers comprise 4.8% of the populations. Five mutations account for 98% of alpha-thalassemia [--SEA 46.7%; -alpha/4.2, 23.9%; -alpha/3.7, 21.7%; hemoglobin (Hb) Constant Spring, 6.5%; Hb Quong Sze, 1.1%]. Seven mutations in the beta-globin gene account for 99% of the mutations [codon (CD) 41/42 (-TCTT) (39.4%), CD 17(A-->T) (32%), CD 71/72 (+A) (7.4%), -28 (A-->G) (5.8%), IVS-2-654 (C-->T) (5.8%), CD26 (Hb E) (4%), IVS-1 (G-->A) (3.7%), and CD 43(G-->T) (1.9%)]. Most individuals with alpha-thalassemia major die in the uterus or shortly after birth. Among 106 patients with beta-thalassemia major followed by our clinic, the majority died before 5 years of age. Knowledge surveys about thalassemia were conducted. Our results show a severe lack of knowledge about thalassemia in both medical professionals and in the general populations. This study shows that thalassemia is a very severe public health issue in minority populations in Baise City, China. Identification of the common mutations will allow us to design cost-effective molecular tests. There is an urgent need to educate the general population and the medical community for a successful community-based prevention program.

CD40{middle dot}FasL inhibits human T cells: evidence for an auto-inhibitory loop-back mechanism

A chimeric CD40.FasL (CD40-CD95L) protein was designed with the combined capacities to bind to two surface receptors on activated T cells, CD40 ligand (CD40L; CD154) and Fas receptor (CD95). CD40.FasL, once tethered to the cell surface via one of its ends, can transmit a signal via its other end. In principle, simultaneous triggering from both ends is possible, and thus there is the intriguing potential for 'auto-inhibition' if such dual triggering occurs on the same cell itself. Several lines of evidence support this mechanism: (i) CD40.FasL is cytotoxic to Fas receptor-positive cell lines of different cell lineages, (ii) CD40.FasL's function is potentiated when there is enforced expression of CD40L on target cells, (iii) CD40.FasL inhibition does not require intercellular contact, as demonstrated by soft agar clone formation and cell dilution analysis and (iv) introduction of exogenous CD40 into the system interferes with CD40.FasL inhibition. Taken together, these data are consistent with a 'loop-back' inhibitory mechanism within individual activated (CD40L and Fas receptor expressing) T cells causing suicide of these T cells. Significantly, this type of fusion protein provides a unique way to confine immunoinhibition to activated T cells.

A rheostatic mechanism for T-cell inhibition based on elevation of activation thresholds

The activation of discrete T-cell responses depends on the triggering of individualized threshold numbers of T-cell receptors (TCRs). The results of this study indicate that the lipocalin placental protein 14 (PP14), a T-cell inhibitor produced by cells of the reproductive and hematopoietic systems, mediates its anti-inflammatory activity by elevating the T-cell activation threshold, thereby rendering T cells less sensitive to stimulation. Significantly, the data demonstrate hierarchical sensitivity of selected cytokine responses to PP14-mediated inhibition, with the hierarchy reflecting their respective activation thresholds. These findings suggest a novel paradigm for immunoinhibition wherein negative regulators can finely tune, rather than inactivate, T-cell responses, and thereby skew the cytokine output of immunologic responses.

High-level expression of recombinant dengue viral NS-1 protein and its potential use as a diagnostic antigen

The prevalence of NS1 Ab response in patients with dengue viral infection and the potential of using recombinant NS1 protein as a diagnostic antigen for dengue viral infection were investigated. In this study, the full-length and C-terminal half of NS1 proteins (rNS1, rNS1-C) were highly expressed (10-30 mg/l) and further purified and refolded. The good antigenicity of the full-length rNS1 protein was confirmed by interaction with 19 dengue NS1-specific monoclonal antibodies (MAbs) in ELISA; however, the antigenicity of rNS1-C was relatively lower. The full-length rNS1 antigen also differentiated reliably between sera from dengue virus-infected patients and sera from normal controls. When rNS1 was used as an antigen to detect human anti-NS1 IgM and IgG Ab, the anti-NS1 Ab response was found in 15 of 17 patients (88%) with primary dengue infection and all 16 patients (100%) with secondary dengue infection. These results indicated that using the full-length rNS1 whose antigenicity is restored as ELISA antigen, a high anti-NS1 antibody prevalence could be detected in patients with either primary or secondary dengue infection. This finding suggested that the anti-NS1 antibody appeared not only in secondary and severe dengue virus infection and might not correlate the pathogenesis of dengue hemorrhagic fever. The study also verified that our purified rNS1 protein showed similar immunological properties as native dengue viral proteins. Genetic engineering production of recombinant NS1 antigen could provide a safe and valuable resource for dengue virus serodiagnosis.

Fragment of Japanese encephalitis virus envelope protein produced in Escherichia coli protects mice from virus challenge

A fragment from the N-terminal part (E(A)) and a fragment from the C-terminal part (E(B)) of the envelope (E) protein of Japanese encephalitis virus (JEV) was synthesized in Escherichia coli. These two fragments were overlapping with each other by nine amino acids, however, they were not cross-reacting with each other at the antisera level. Both E(A)and E(B)are antigenic by themselves when injected into mice, but when tested against sera from mice, rabbit, swine and human that had been immunized or naturally infected with JEV, E(B)acted as a better antigen than E(A)by ELISA assays. E(B)also proved to be a better immunogen in protection against lethal JEV infection than E(A). The protection appears to be correlated with the neutralizing titres of the anti-JEV sera. The response elicited by E(B)is a Th1 response and the antibody produced contained higher neutralizing titre than E(A)fragment. The major difference between E(A)and E(B)fragments is the solubility during expression in E. coli, while E(B)fragment is soluble, E(A)was isolated from the insoluble inclusion bodies. Therefore the antigenicity and immunogenicity expressed by the E(B)fragment may probably be due to its proper folding to assume a correctly assembled form during expression in E. coli, a quality that is important for a protein to qualify as a good vaccine candidate.

CREB is one component of the binding complex of the Ces-2/E2A-HLF binding element and is an integral part of the interleukin-3 survival signal

The Ces-2/E2A-HLF binding element (CBE) is recognized by Caenorhabditis elegans death specification gene product Ces-2 and human acute lymphocytic leukemia oncoprotein E2A-HLF. In an attempt to identify a cellular CBE-binding protein(s) that may be involved in apoptosis regulation in mammals, multiple nuclear binding complexes of CBE were identified in various mammalian cell lines and tissues by electrophoretic mobility shift assay. Cyclic AMP (cAMP)-responsive element (CRE)-binding protein (CREB) was present in one major CBE complex of Ba/F3 and TF-1 cells, and both in vitro-translated and Escherichia coli-synthesized CREB bound to CBE. Activation of CREB by cAMP-elevating chemicals or the catalytic subunit of protein kinase A (PKAc) resulted in induction of the CBE-driven reporter gene. Stimulation of Ba/F3 cells with interleukin-3 (IL-3) promptly induced phosphorylation of CREB at serine(133) partially via a PKA-dependent pathway. Consistently, Ba/F3 cell survival in the absence of IL-3 was prolonged by activation of PKA. Conversely, treatment of cells with a PKA inhibitor or expression of the dominant negative forms of the regulatory subunit type I of PKA and CREB overrode the survival activity of IL-3. Last, the bcl-2 gene was demonstrated to be one candidate cellular target of the CREB-containing CBE complex, as mutations in the CRE and CBE sites significantly reduced the IL-3 inducibility of the bcl-2 promoter. Together, our results suggest that CREB is one cellular counterpart of Ces-2/E2A-HLF and is part of IL-3 dependent apoptosis regulation in hematopoietic cells.

[Preliminary study on the absorption, distribution and excretion of doxophylline in rats]

Doxophylline, a new antibronchospastic drug, being more active and less toxic than aminophyline, was detected by high-performance thin layer chromatography. The pharmacokinetics of doxophylline have been characterized in rats, whose serum concentration were monitored after 100, 200, 400 mg.kg-1 oral dose. The drug was found to conform to a one-compartment model and can be bio-transformed quickly in rats. The Cmax, AUC and CL/F appeared to be dose-dependent. T1/2 (Ke) was 1.17 +/- 0.13 h after the 100 mg.kg-1 dose, 2.54 +/- 0.60 h after the 200 mg.kg-1 dose and 3.75 +/- 0.92 h after the 400 mg.kg-1 dose. The doxophylline concentration in tissues decreased rapidly. Total excretion of the drug in urine, bile and faeces was 5.2 per cent of the dose. Plasma protein binding was about 25 percent.

CTLA-4-Fas ligand functions as a trans signal converter protein in bridging antigen-presenting cells and T cells

Co-stimulator blockade and trans inhibitory signaling, using agents such as CTLA-4-Ig and Fas ligand (FasL) respectively have been invoked as alternative strategies for suppressing pathogenic T cells. This study describes a novel hetero-bifunctional fusion protein, CTLA-4-FasL, designed to combine within a single protein both co-stimulator blocking and trans inhibitory signaling potentials. A chimeric expression cassette, in which the ectodomain coding sequences for CTLA-4 and FasL were linked in-frame, was used to produce a CTLA-4-FasL fusion protein. CTLA-4-FasL binding to both B7-1/B7-2-expressing Daudi B cells and Fas-expressing Jurkat T cells was documented by immunofluorescence and flow cytometry. The capacity of CTLA-4-FasL to induce apoptosis in Jurkat targets was markedly enhanced by the addition of Daudi and other B7-1/B7-2(+) B cell lines, which provided a membrane platform for the otherwise soluble CTLA-4-fusion protein. Moreover, in dual-chamber experiments, Daudi cells pre-coated with CTLA-4-FasL demonstrated Jurkat inhibitory activity that was cell-contact dependent. Significantly, when used to inhibit in vitro cellular proliferation of peripheral blood mononuclear cells, CTLA-4-FasL was approximately 1000-fold more potent than the extensively characterized CTLA-4-Ig fusion protein. Furthermore, the degree of inhibition induced by CTLA-4-FasL substantially surpassed that observed for CTLA-4-Ig and a soluble FasL when used in combination. CTLA-4-FasL represents the first of a novel class of fusion proteins, designated here as 'trans signal converter proteins', that combine trans signal masking and direct trans signaling functions.

Antibody to the nonstructural protein NS1 of Japanese encephalitis virus: potential application of mAb-based indirect ELISA to differentiate infection from vaccination

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect and differentiate the antibody responses to Japanese encephalitis (JE) virus nonstructural protein NS1 between infected and vaccinated individuals. The results showed that all convalescent sera from JE patients contained NS1-specific IgG antibodies, while 65 and 40% of these sera showed detectable NS1-specific IgM and IgA antibodies, respectively. Specificity analysis showed that NS1-specific IgM and IgA antibodies from JE patients do not cross-react to dengue virus NS1 glycoprotein, while IgG antibodies from 10% of JE patients showed significant cross-reaction to dengue virus NS1 glycoprotein. To differentiate infection from vaccination, the immune sera from 24 children vaccinated with inactivated JE vaccine were analyzed. The data showed that none of these immune sera had detectable NS1-specific IgG antibodies. The results demonstrated the potential application of JE NS1-specific indirect ELISA to differentiate infection from vaccination.

The expression and potential function of cellular prion protein in human lymphocytes

We examined expression of the normal cellular prion protein (PrP(C)) in human peripheral blood mononuclear cells (PBMC) and in transfected neuroblastoma cells with a panel of six monoclonal antibodies (Mabs). While all six of the Mabs reacted strongly with the neuroblastoma cells, only four of the Mabs reacted with PrP(C) expressed by human PBMC. PrP(C) is expressed at high levels in human T cells, B cells, monocytes, and dendritic cells, but not in red blood cells. Immunoblotting studies revealed that the PrP(C) glycoforms and the composition of the N-linked glycans on PrP(C) in human PBMC are different from those of the brain or the neuroblastoma cells. In human PBMC and the neuroblastoma cell lines the N-terminal portion of the PrP(C) is hypersensitive to proteolytic digestion, suggesting that the N-terminus of the PrP(C) on the surface of a living cell lacks secondary structure. We found that the level of PrP(C) expressed on the surface of human T lymphocytes was up-regulated as a consequence of cellular activation. Accordingly, memory T cells express more PrP(C) than naïve T cells. In addition, the proliferation of human T lymphocytes stimulated with an anti-CD3 Mab was inhibited by anti-PrP(C) Mabs. Collectively, these results suggest that PrP(C) can participate in signal transduction in human T lymphocytes.

The role of cell density in the survival of cultured cerebellar granule neurons

The dependence for survival of cerebellar granule neurons on the cell density was examined both experimentally and theoretically. The results of batch experiments revealed that the cell survival index (CSI) was inappreciable, if cell density was below a critical level. If cell density exceeded this critical value, CSI increased with the increase in cell density. In addition, CSI was significantly increased by using a conditioned medium from the dense cultures. This suggests that not only cell density promotes survival of neurons, but also an increased concentration of growth factors produced by neurons has a direct effect on the survival of the neurons. A quantitative model describing the distribution of the growth factor at different cell densities was proposed to investigate the role of cell density in the survival of the neurons. We showed the existence of a critical level for cell density, and good agreement in the improvement of CSI was found between the theoretical prediction and the experimental result. Finally, the average concentration of growth factor necessary for cell survival based on our model was in a reasonable range compared to the practice of the addition of neurotrophic factors to the medium of cultured cerebellar granule neurons.

NFkappa B interacts with serum amyloid A3 enhancer factor to synergistically activate mouse serum amyloid A3 gene transcription

We had previously identified a distal regulatory element (DRE) in the mouse serum amyloid A3 (SAA3) promoter that functions as a cytokine-inducible transcription enhancer. Within this DRE, three functional elements interact with CCAAT/enhancer-binding protein (C/EBP) and SAA3 enhancer factor (SEF) transcription factors. In this study, we show that cotransfection of the SEF expression plasmid with an SAA3/luciferase reporter resulted in 3-5-fold activation of the SAA3 promoter. When SEF-transfected cells were further stimulated with conditioned medium or interleukin-1, SAA3 promoter activity was dramatically increased, suggesting that SEF may cooperate functionally with other interleukin-1-inducible transcription factors to synergistically up-regulate SAA3 gene transcription. Indeed, cotransfection of SEF and NFkappaBp65 expression DNAs resulted in synergistic activation of the SAA3 promoter. Intriguingly, no consensus NFkappaB-binding site was found in the SAA3 promoter region; rather a putative NFkappaB-binding sequence with 3-base pair mismatches was identified in the DRE. When this sequence was used in an electrophoretic mobility shift assay, it interacted with NFkappaBp50, albeit with binding affinities that were several hundredfold lower than that with the consensus NFkappaB probe. Functional cooperation between SEF and NFkappaB was further strengthened by the finding that SEF and NFkappaB formed stable cytokine-inducible protein-protein complexes. Finally, despite its weak binding, mutation of this NFkappaB-binding site nevertheless dramatically reduced both NFkappaBp65- and cytokine-mediated induction of SAA3 promoter. Therefore, the molecular basis for the functional synergy between SEF and NFkappaB may, in part, be the ability of SEF to recruit NFkappaB through physical interactions that lead to enhancement or stabilization of NFkappaB binding to the SAA3 promoter element.

Dengue NS1-specific antibody responses: isotype distribution and serotyping in patients with Dengue fever and Dengue hemorrhagic fever

To understand the antibody responses to dengue (DEN) nonstructural 1 (NS1) glycoprotein and their roles in protective immunity or pathogenesis of dengue fever (DF) and dengue hemorrhagic fever (DHF), we have analyzed the NS1-speccific IgM, IgA and IgG antibodies from patients with DF and DHF. An isotype-specific, indirect enzyme-linked immunosorbent assay (ELISA) was established by coating a NS1-specific monoclonal antibody (MAb), D2/8-1, to capture soluble NS1 antigens secreted in the culture supernatants of Vero cells infected with DEN virus. We observed strong anti-NS1 antibody responses in all of the convalescent sera of patients with DF and DHF. Similar NS1-specific isotypic and serotypic antibody responses were found in the sera from DF and DHF patients. The results showed that all DEN infections induced significant NS1-specific IgG, whereas 75% and 60% of primary DF patients vs. 40% and 90% of secondary DF patients produced IgM and IgA antibodies, respectively. Specificity analysis showed that DEN NS1-specific IgG and IgA antibodies cross-react strongly to Japanese encephalitis (JE) virus NS1 glycoprotein, whereas DEN NS1-specific IgM antibodies do not cross-react to JE virus NS1 glycoprotein at all. The serotype specificity of NS1-specific IgM, IgA and IgG were found to be 80%, 67% and 75% for primary infections, and 50%, 22% and 30% for secondary infections in positive samples of DF patients. Similar pattern was found in DHF patients. The results showed that all of the DF and DHF patients produced significant NS1-specific antibodies. We did not observe direct correlation between the anti-NS1 antibody responses and DHF because sera from patients with DF and DHF showed similar anti-NS1 antibody responses.

Spatial mapping of the zone of secondary hyperalgesia reveals a gradual decline of pain with distance but sharp borders

The purpose of this study was to examine how pain to punctate mechanical stimuli varies with position within the zone of secondary hyperalgesia. Secondary hyperalgesia was produced by an intradermal injection of capsaicin (50 microg) into the volar forearm of human volunteers (n=9). Before and at 20, 60 and 100 min after the capsaicin injection, a computer-controlled electromechanical stimulator was used to deliver controlled-force stimuli to the skin via a 12-mm wide, 100-microm thick blade probe. Three forces (16, 32 and 64 g; 1 s) were each applied in a random order to 10 sites spaced in 1-cm increments along a line starting 1 cm from the injection site and ending near the wrist. At 40 and 80 min after capsaicin injection the 'zone of hyperalgesia' was determined with use of a hand-held 20-g von Frey probe. Whereas, before capsaicin, the blade probe produced little or no pain, after capsaicin the 32-g and 64-g stimuli evoked pain consistently within but not outside the border of secondary hyperalgesia determined with the von Frey probe. Within the zone of hyperalgesia the average pain ratings to the 64-g stimulus decreased exponentially with distance from the injection site. Surprisingly, the space constant for this exponential decay was large (about 18 cm), and thus the decrease in pain ratings from the center to the edge of the secondary zone was small (37%). However, pain ratings dropped precipitously just outside the zone of secondary hyperalgesia. This finding unlikely reflects a ceiling effect because pain ratings within the zone of secondary hyperalgesia increased linearly with force. The relatively uniform pain ratings to the blade stimuli within the zone of secondary hyperalgesia and the sharp border that delimits the zone of hyperalgesia indicate that this sensory disturbance approaches being an 'all-or-nothing' phenomenon. Thus, a two-state model for central plasticity is needed to explain secondary hyperalgesia.

Phosphatidylinositol 3-kinase as a mediator of TNF-induced NF-kappa B activation

The activation of transcription factor NF-kappa B by TNF involves the stimulation of a novel signaling cascade. In this paper we show that phosphatidylinositol 3-kinase (PI 3-kinase) may play a pivotal role in TNF-mediated activation of NF-kappa B-dependent genes. Consistent with its involvement in TNF signaling, PI 3-kinase activities in HepG2 and U937 cells can be stimulated by TNF in a rapid but transient manner through a mechanism that may involve its association with the insulin receptor substrate-1. A dominant-negative mutant of the p85 regulatory subunit of PI 3-kinase, which is a potent inhibitor of PI 3-kinase signaling, effectively blocked the TNF-induced expression of an NF-kappa B-dependent reporter gene. Although PI 3-kinase may be required for NF-kappa B activation, overexpression of its p110 catalytic subunit alone was unable to induce an NF-kappa B/chloramphenicol acetyltransferase (CAT) reporter gene. However, when TNF was added to p110-overexpressing cells, there was a synergistic activation of the NF-kappa B/CAT reporter, suggesting that other TNF-inducible signals may cooperate with PI 3-kinase to activate NF-kappa B. Consistent with its role in NF-kappa B activation, inhibition of PI 3-kinase activity by wortmannin or LY294002 greatly potentiated TNF-induced apoptosis. This TNF/wortmannin-induced apoptosis was markedly prevented in cells overexpressing Rel A. Taken together, our results indicate that a PI 3-kinase-regulated step in TNF-signaling is critical for the expression of NF-kappa B-dependent genes.