N-methyl-D-aspartate receptors enhance mechanical responses and voltage-dependent Ca2+ channels in rat dorsal root ganglia neurons through protein kinase C

N-methyl-D-aspartate (NMDA)receptors (NMDARs) located on peripheral terminals of primary afferents are involved in the transduction of noxious mechanical stimuli. Exploiting the fact that both NMDARs and stretch-activated channels are retained in short-term culture and expressed on the soma of dorsal root ganglia (DRG) neurons, we examined the effect of NMDA on mechanically mediated changes in intracellular calcium concentration ([Ca2+]i). Our aims were to determine whether NMDARs modulate the mechanosensitivity of DRG neurons. Primary cultures of adult rat lumbosacral DRG cells were cultured for 1-3 days. [Ca2+]i responses were determined by Fura-2 ratio fluorescence. Somas were mechanically stimulated with fire-polished glass pipettes that depressed the cell membrane for 0.5 s. Voltage-activated inward Ca2+ currents were measured by the whole cell patch clamp. Stimulation of neurons with 100 microM NMDA in the presence, but not the absence, of co-agonist (10 microM D-serine) caused transient [Ca2+]i responses (101+/-9 nM) and potentiated [Ca2+]i peak responses to subsequent mechanical stimulation more than two-fold (P < 0.001). NMDA-mediated potentiation of mechanically induced [Ca2+]i responses was inhibited by the selective protein kinase C (PKC) inhibitor GF109203X (GFX; 10 microM), which had no independent effects on NMDA- or mechanically induced responses. Short-term treatment with the PKC activator phorbol dibutyrate (1 microM PDBu for 1-2 min) also potentiated mechanically induced [Ca2+]i responses nearly two-fold (P < 0.001), while longer exposure (>10 min) inhibited the [Ca2+]i transients by 44% (P < 0.001). Both effects of PDBu were prevented by prior treatment with GFX. Inhibition of voltage-dependent Ca2+ channels with 25 microM La3+ had no effect on mechanically induced [Ca2+]i transients prior to NMDA, but prevented enhancement of the transients by NMDA and PDBu. NMDA pretreatment transiently enhanced nifedipine-sensitive, voltage-activated Ca2+ currents by a process that was sensitive to GFX. In conclusion, activation of NMDARs on cultured DRG neurons sensitize voltage-dependent L-type Ca2+ channels which contribute to mechanically induced [Ca2+]i transients through a PKC-mediated process.

Observation of a threshold enhancement in the plambda invariant-mass spectrum

An enhancement near the m(p)+M(Lambda) mass threshold is observed in the combined pLambda and pLambda invariant-mass spectrum from J/psi-->pK(-)Lambda;+c.c. decays. It can be fit with an S-wave Breit-Wigner resonance with a mass m=2075+/-12(stat)+/-5(syst) MeV and a width of Gamma=90+/-35(stat)+/-9(syst) MeV; it can also be fit with a P-wave Breit-Wigner resonance. Evidence for a similar enhancement is also observed in psi(')-->pK(-)Lambda;+c.c. decays. The analysis is based on samples of 5.8x10(7)J/psi and 1.4x10(7)psi(') decays accumulated in the BES II detector at the Beijing Electron-Positron Collider.

Observation of the decay psi(2S)-->K0SK0L

The decay psi(2S)-->K(0)(S)K(0)(L) is observed using psi(2S) data collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider; the branching fraction is determined to be B(psi(2S)-->K(0)(S)K(0)(L))=(5.24+/-0.47+/-0.48)x10(-5). Compared with J/psi-->K(0)(S)K(0)(L), the psi(2S) branching fraction is enhanced relative to the prediction of the perturbative QCD "12%" rule. The result, together with the branching fractions of psi(2S) decays to other pseudoscalar meson pairs (pi(+)pi(-) and K+K-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.

Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays

We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.

Production of gamma-linolenic acid by disrupted mycelia of Mortierella isabellina

AIMS

To optimize the production of linolenic acid by disrupted mycelia of Mortierella isabellina.

METHODS AND RESULTS

Effects of incubation conditions such as incubation time, pH of reaction mixture, concentration of Mg2+ or malate and incubation temperature on production of linolenic acid were studied. The production of gamma-linolenic acid reached 224 mg g-1 dry cells when the reaction mixture was composed of 1.0 g (dry mycelial mass) of disrupted mycelia of M. isabellina, 50 ml (50 mmol l(-1)) potassium phosphate buffer supplemented with 0.312 mmol l(-1) of Mg2+ and 10 mmol l(-1) of malate, pH 7.0 and incubated at 5 degrees C for 1 day.

CONCLUSIONS

Incubation temperature, concentration of Mg2+ and malate showed major effects on the increased linolenic acid production.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study highlights conditions for increasing gamma-linolenic acid production by cell-free mycelia of M. isabellina and an insight into rapidly gaining high production of polyunsaturated fatty acids.

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

The proximal and distal C-terminal tail domains of the CB1 cannabinoid receptor mediate G protein coupling

The human CB1 cannabinoid receptor couples to G(i/o) proteins and inhibits neuronal voltage-gated Ca2+ channels. The role of the C-terminal tail of the CB1 cannabinoid receptor in G(i/o) protein coupling was examined using the superior cervical ganglion neuronal expression system. Deletion of the distal intracellular C-terminal tail (amino acids 418-472) slowed the kinetics and reduced the magnitude of Ca2+ channel inhibition. Deletion of the entire intracellular C-terminal tail (amino acids 401-472) abolished Ca2+ channel inhibition demonstrating the critical role of the proximal amino acids 401-417 of the C-terminal tail in G protein signaling. Expression of the C-terminal truncated receptors on the cell surface was examined using an N-terminal CB1 antibody. Both the C-terminal truncated receptors were expressed on the cell surface and were no different from wild type CB1 cannabinoid receptors. This study establishes that the proximal CB1 cannabinoid receptor intracellular C-terminal tail domain (amino acids 401-417) is critical for G(i/o) protein coupling and that the distal C-terminal tail domain (amino acids 418-472) profoundly modulates both the magnitude and kinetics of signal transduction. Thus, the C-terminal tail of the CB1 cannabinoid receptor has a wider role in G protein coupling than was previously thought.

Structural domains of the CB1 cannabinoid receptor that contribute to constitutive activity and G-protein sequestration

The CB1 cannabinoid receptor is a constitutively active receptor that can sequester G(i/o)-proteins and prevent other G(i/o)-coupled receptors from signaling (Bouaboula et al., 1997; Pan et al., 1998; Vasquez and Lewis, 1999). G-protein sequestration occurs because the population of CB1 cannabinoid receptors exists in both an inactive G-protein-precoupled RG(GDP) state and a constitutively active R*G(GTP) state. We tested the hypothesis that the distal C-terminal tail acts to prevent G-protein activation. We found that truncation of the distal C-terminal tail of the CB1 receptor (CB1-417) enhanced both the constitutive activity and the ability of the receptor to sequester G-proteins. In addition, we tested the hypothesis that the conserved aspartate (D2.50) in the second transmembrane domain of the CB1 cannabinoid receptor is crucial for constitutive activity and G-protein sequestration. We found that the mutation of aspartate to asparagine (CB1-D164N) abolished G-protein sequestration and constitutive receptor activity without disrupting agonist-stimulated activity. We conclude that the CB1-D164N mutation and the C-terminal truncation shift the population of receptors in opposite directions. The CB1-D164N mutation shifts the receptor into an inactive R state upcoupled from G-proteins, whereas the C-terminal truncation (CB1-417) shifts the receptor into the active R*G(GTP) state. Thus the distal C-terminal tail acts to constrain the receptor from activating G-proteins, whereas the aspartate (D2.50) in the second transmembrane domain stabilizes the receptor in both the inactive RG(GDP) state and the active R*G(GTP) state.

Synthesis and characterization of N-isopropyl, N-methacryloxyethyl methacrylamide as a possible dental resin

In this study, N-isopropyl, N-methacryloxyethyl methacrylamide (NIMM) is proposed as a possible reactive diluent in place of triethylene glycol dimethacrylate (TEGDMA) for dental resin mixtures. Real-time infrared spectroscopy was used to monitor the double-bond conversion as a function of irradiation time, and mixtures of 50/50wt% bis-GMA/NIMM were found to reach final conversions (95%) that were 1.5 times greater than bis-GMA/TEGDMA (65%) under visible light irradiation. In addition, samples cured to these conversions were tested with dynamic mechanical analysis. The bis-GMA/NIMM mixture (100% converted) was found to have a higher glass transition temperature and modulus at body temperature than a comparable bis-GMA/TEGDMA mixture (60% converted). Finally, the water sorption and solubility of bis-GMA/NIMM were determined to be higher than the bisGMA/TEGDMA comparison, but the values were still within the range of the ISO 9000s standard. These results suggest that bis-GMA/NIMM mixtures are a viable alternative to conventional dental resins since a greater degree of monomer conversion is obtainable without sacrificing physical and mechanical properties.

Neuroprotective effects in gerbils of spiramine T from Spiraea japonica var. acuta

The neuroprotective effects of spiramine T, an atisine-type diterpenoid alkaloid isolated from the Chinese herbal medicine Spiraea japonica var. acuta (Rosaceaee), on cerebral ischemia-reperfusion injury produced by 10-min bilateral occlusion of the common carotid arteries followed by 5-day reperfusion in gerbils were investigated. Intravenous spiramine T (0.38, 0.75, and 1.5 mg.kg-1) markedly reduced the stroke index, enhanced the recovery of EEG amplitude during reperfusion and decreased the concentrations of cortex calcium and LPO in a dose-dependent manner. However, no significant effects on water and sodium contents were observed. These results suggested that spiramine T exhibited protective effects on cerebral ischemia-reperfusion injury in gerbils, and its mechanism might be related to reducing calcium accumulation and lipid peroxidation. This is the first report on spiramine T as a natural product with neuroprotective effects.

[Cancer pain and its influence on cancer patients' quality of life]

OBJECTIVE

To study cancer pain and its effect on cancer patients' quality of life.

METHODS

Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and Brief Pain Inventory (BPI) methods were used to investigate cancer pain, its effect on patients' quality of life and management in 200 cancer inpatients.

RESULTS

The incidence of cancer pain was 69%, including 21.5% with mild pain, 19% with moderate pain and 28.5% with severe pain. Moderate and severe pain occurred more frequently in patients with cancer of the digestive tract. No correlation was found between pain and stage of the disease, but was closely associated with bone metastasis. Regardless of its severity, cancer pain seriously affected patients general activity, mood, walking ability, normal work and sleep. With the seriousness of pain, the patients were more affected. However, there was no obvious difference between moderate and severe pain in terms of their effect on the patients' joy of life and relations with people. The effect of moderate pain on patients' mentality appeared earlier than did severe pain. Among patients with cancer pain, 41.3% of them did not receive proper treatment. Only 52.1% of patients with severe pain were given strong opioids, which is far from the anti-pain standard set forth by the WHO.

CONCLUSION

Cancer pain is one of the most important factors which affect cancer patients' quality of life. For adequate control of cancer pain, there is still a long way to go to achieve WHO's goal.

[An epidemiological study on acute diarrhea during a filed exercise in PLA unit in an area in southern China]

OBJECTIVE

To explore the epidemiological characteristics and risk factors of acute diarrheal disease during a filed exercise.

METHODS

Epidemiological study of a certain artillery acute diarrheal disease during a filed exercise and multiple linear stepwise regression analysis, multiple stepwise discriminate analysis were used.

RESULTS

Result showed that the incidence rate of training troops was significantly higher than that of the local troops at the corresponding period (7.32% vs 0.98% P<0.05). The incidence rate among officers was significantly lower than that of the soldiers (0.99% vs 8.20% P<0.05). The incidence rate was significantly higher at the beginning of assemble for training but smooth and steady afterwards with several outbreaks. There was highly significant difference in the incidence rate of 39 companies. Regression and discrimination analysis suggested that the incidence rate was correlated with the density of flies and average boiled water volume provided everyday. The correct classifying rate of the discrimination was 91.9% in total.

CONCLUSION

These results provided a basis for prevention of acute diarrheal disease during filed exercise of military action.

Cutting edge: phorbol ester induction of IFN-gamma receptors leads to enhanced DR alpha gene expression

We observed that IFN-gamma-inducible expression of the DR alpha gene was enhanced when THP-1 cells are differentiated into macrophage-like cells by phorbol ester treatment. Here, we observed that class II MHC trans-activator and STAT1 alpha mRNA, mediators of the signaling cascade from the IFN-gamma receptor to the DR alpha induction, were markedly increased by IFN-gamma stimulation in phorbol ester-activated THP-1 cells; however, both mRNAs were not increased by phorbol ester treatment alone. Then, we demonstrated that the mRNA and proteins of the IFN-gamma receptor alpha- and beta-chains were amplified by phorbol ester treatment in THP-1 cells. Consequently, these results indicate that the enhancement of DR alpha gene expression by IFN-gamma treatment in phorbol ester-activated THP-1 cells is due to the phorbol ester-induced up-regulation of IFN-gamma receptor alpha- and beta-chains. As a result, the amplification of STAT1 alpha and the increment of class II MHC trans-activator results in enhancement of DR alpha expression.

A binding protein to the DNase I hypersensitive site II in HLA-DR alpha gene was identified as NF90

We previously observed that IFN gamma-inducible expression of the human MHC class II, HLA-DR alpha, gene was enhanced by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) only in human monocytic leukemia THP-1 cells, but not in HeLa cells. In the HLA-DR alpha gene, three DNase I hypersensitive sites (DHS) are known to be present in the promoter region (DHS-I) and first intron (DHS-II and -III) and are assumed to be involved in HLA-DR alpha gene regulation. In this study, we found a binding factor which recognized a unique palindrome sequence (DHS-22) in the region of the DHS II site of the HLA-DR alpha gene in THP-1 cells and HeLa cells. The binding activity of this factor was decreased by TPA treatment in THP-1 cells, but not in HeLa cells. This binding activity was also detectable in nuclear extracts of bovine brains. Thus, we isolated the DHS-22 binding factor from bovine brain nuclear extracts and finally identified it as NF90 on the basis of molecular mass analysis of Lys-C-digested fragments and amino acid sequences of the two peptides of the trypsin-digested binding protein. The DHS-22 binding protein(s) in THP-1 cells is (are) further confirmed by reactivity to an antibody against NF90, and we have demonstrated that the GST fusion protein of NF90 interacts with DHS-22 by electrophoretic gel mobility shift assay (EMSA). The mRNA of NF90 was decreased by TPA treatment in THP-1 cells but not in HeLa cells. These results suggest that the binding of NF90 to the DNase I hypersensitive site II of HLA-DR alpha gene seems to negatively regulate HLA-DR alpha gene expression.

Highly cross-linked networks for dental applications obtained by photocuring of tris[2-(acryloyloxy)ethyl]isocyanurate, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol triacrylate, and pentaerythritol triacrylate

Highly cross-linked networks have been obtained by photoinitiated camphorquinone-amine polymerization of tris[2-(acryloyloxy)ethyl]isocyanurate alone and/or with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol triacrylate or pentaerythritol triacrylate, which can be considered a new class of dental restorative resins. The most effective coinitiators in this system are amines such as ethyl-4-dimethylaminobenzoate, N,N-dimethyl-benzylamine, and 2,4,6-tris(dimethylaminomethyl)phenol. The volume shrinkages of polymerized samples were 8%-13%. The hardness of photocured resins in the presence of an inorganic filler (aluminum/fluoro/silicate glass, Ketac-Fil was slightly less than that of a restorative composite material (Z100 MP).

A transiently chaotic neural-network implementation of the CDMA multiuser detector

The complex dynamics of the chaotic neural networks makes it possible for them to escape from local minimum of the simple gradient descent neurodynamics. In this letter we use a transiently chaotic neural network to detect the CDMA multiuser signals and hence obtain an implementation scheme of the CDMA multiuser detector (TCNN-MD). Computer simulation results show that the proposed detector is clearly superior to Hopfield neural-network-based detector.