Diffusion tensor imaging in hydrocephalus: initial experience

PURPOSE AND BACKGROUND

Diffusion tensor imaging (DTI) is an MR imaging-based technique that provides an in vivo tool for visualization of white matter tracts. In this preliminary study, we used this technique to investigate the diffusion characteristics of white matter tracts in patients with hydrocephalus before and after surgery and compared them with age-matched volunteers.

MATERIALS AND METHODS

Seven patients with different types of acute hydrocephalus (defined by acute clinical signs of increased intracranial pressure and imaging evidence of enlarged ventricles) underwent MR imaging including a DTI protocol before and after surgery for shunt placement/revision or ventriculostomy. Eight age-matched healthy subjects served as a control group. The DTI was acquired in a clinical setting that included 6 gradient directions with a b value of 1000 s/mm(2).

RESULTS

Before surgery, in fiber systems lateral to the ventricles (corona radiata), the diffusion parallel to the fibers was increased (+10%) and the diffusion perpendicular to the fibers was decreased (-25%) in all patients, resulting in an overall increase in the fractional diffusion anisotropy (FA, +28%). Following surgery, the FA values approached those of control values in all except 1 patient. In the corpus callosum, the presurgery FA values in patients with hydrocephalus (HCP) were lower than those of control values, and no significant changes were seen following surgery.

CONCLUSIONS

DTI can distinguish the compression characteristics of white matter before and after surgery in patients with HCP. At the acute stage of the disease, DTI characteristics point to white matter compression as a possible cause of the observed changes.

Splenic tumour: a clinicopathological study

Splenic tumours are occasionally found during routine physical check-ups or elective abdominal image studies. Histologically, most splenic tumours are of benign vascular origin. To avoid unnecessary surgery for asymptomatic patients with benign splenic tumours and clarify the clinicopathological features of spleen tumours, this study gathered 44 cases of primary or isolated metastatic spleen tumours confirmed by pathology from surgery specimens or biopsies. The differences in clinicopathological features and image presentations between benign and malignant spleen tumour were investigated. Thirty-two cases involved benign tumours while 12 cases were malignant. Among the benign tumours, vascular originating tumours were most common (with 14 cases of cavernous haemangiomas, 13 cases of lymphangioma, three cases of lymphangiohaemangioma and one case of Littoral cell angioma). Notably, one, case of inflammatory pseudotumour because of Schistosoma parasite infection was also noted. Among the malignant tumours, there were four cases of angiosarcomas with vascular endothelium origins, as well as lymphomas and six metastatic tumours. Image studies were non-specific. Image study alone is an inadequate basis for making differential diagnoses between benign and malignant tumours. Instead, pathological studies are required for a final diagnosis. Using previous studies and this investigation, fine needle aspiration biopsy of spleen tumours with the help of ultrasonic or computed tomography appears a safe and effective method for obtaining biopsy specimens. Splenectomy is recommended only for patients with malignancies or complications such as intractable abdominal pain, coagulopathy or tumour rupture with an unstable haemodynamic state.

Stability of 4-DMAP in solution

A stability-indicating reversed-phase performance liquid chromatographic method was developed for the detection of 4-(N,N-dimethylamino)phenol (4-DMAP) and its degradation products under accelerated degradation conditions. The degradation kinetics of 4-DMAP in aqueous solution over a pH range of 1.12-6.05 and its stability in solutions based on propylene glycol or polyethylene glycol 400 were investigated. The observed rate constants were shown to follow, apparent first-order kinetics in all cases. The pH rate profile shows that maximum stability of 4-DMAP was observed in the pH range 2.0 to 3.0. Acid/base catalysis of 4-DMAP was not affected by systems of various ionic strengths. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.05 solution of 4-DMAP showed an increase in the stability at 55 degrees C +/- 0.5 degrees C.

Inhibition of extracellular Ca(2+) entry by YC-1, an activator of soluble guanylyl cyclase, through a cyclic GMP-independent pathway in rat neutrophils

The effects of a soluble guanylyl cyclase (sGC) activator, 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1), on formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated [Ca(2+)](i) elevation in rat neutrophils were examined. YC-1 produced a concentration-dependent inhibition of [Ca(2+)](i) elevation. Pretreatment of neutrophils with YC-1 did not enhance its inhibitory effect. YC-1 also inhibited the [Ca(2+)](i) changes caused by ionomycin. In a biphasic model, measuring the [Ca(2+)](i) stimulation by fMLP in a Ca(2+)-free medium followed by reintroduction of Ca(2+), YC-1 mainly affected Ca(2+) influx. YC-1 also inhibited active and passive Mn(2+) influx, and this inhibitory effect was not attenuated by the sGC inhibitor 6-anilino-5,8-quinolinequinone (LY83583). Sodium nitroprusside did not affect the fMLP-stimulated [Ca(2+)](i) changes. Pretreatment of neutrophils with the cyclic GMP-dependent protein kinase inhibitor 8-(4-chlorophenylthio) guanosine-3',5'-monophosphorothioate, Rp-isomer (Rp-8-pCPT-cGMPS), LY83583, the protein phosphatase 2B inhibitor cyclosporin A, or the protein kinase inhibitor staurosporine did not attenuate the inhibition of [Ca(2+)](i) by YC-1. YC-1 inhibited the fMLP-stimulated protein tyrosine phosphorylation. These results indicate that cyclic GMP does not play an important role in the regulation of [Ca(2+)](i) in rat neutrophils. Inhibition of fMLP-stimulated [Ca(2+)](i) changes by YC-1 is mainly via the blockade of Ca(2+) entry through the inhibition of tyrosine kinase activity, but not the stimulation of protein kinase C and protein phosphatase 2B.

Signal transduction pathways for activation of extracellular signal-regulated kinase by arachidonic acid in rat neutrophils

Phosphorylation of extracellular signal-regulated kinase (ERK) in response to arachidonic acid (AA) was rapid and transient, peaking at 1 min and disappearing after 3 min, and it was accompanied by an increase in ERK activity in rat neutrophils. We examined the upstream regulation of AA-stimulated ERK activation using one of the following signaling pathway inhibitors to pretreat rat cells: the ERK kinase inhibitor U0126 or PD98059, the G(i/o) inhibitor pertussis toxin (PTX), the tyrosine kinase inhibitor genistein, the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin or LY294002, the Ca2+ chelator 1,2-bis(O-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid, or the phospholipase C (PLC) inhibitor U73122. All of these inhibitors attenuated AA-induced ERK activation. Activation of ERK was also effectively attenuated by the cyclooxygenase and lipoxygenase inhibitor BW755C and by the leukotriene biosynthesis inhibitor MK886, but the cyclooxygenase inhibitor indomethacin did not attenuate ERK activation. After exposing cells to three distinct protein kinase C (PKC) inhibitors, we found that Gö6976 significantly attenuated ERK phosphorylation but potentiated ERK activity. Neither Gö6983 nor GF109203X affected AA-induced responses. These data suggest that the lipoxygenase metabolite(s) produced mediates AA-stimulated ERK activation and that this effect is upstream regulated by PT-sensitive G protein, non-receptor tyrosine kinase, PI3K, and PLC/Ca2+ signaling pathways in rat neutrophils.

The reappraisal of nephrocalcin--its role in the inhibition of calcium oxalate crystal growth and interaction with divalent metal ions

Nephrocalcin (NC) is a potent crystal growth inhibitor of calcium oxalate monohydrate. However, the sequence is undefined owing to its multiple glycosylations. Although there have been many biochemical studies of the binding capacity of calcium, the study of the function of the domain is still deferred. By using S-200 gel filtration and Mono Q ion-exchange chromatographic procedures, NC can be purified without further treatment for the removal of urobilirubin. The kinetic study of crystal growth in calcium oxalate monohydrate is performed using a seed slurry system. NC was cut into two peptides through interaction with copper ion and ascorbic acid. The interaction site of the copper ion is presumed to be located between 8 and 6 kDa of molecular weight in NC. The data suggest that divalent metal ions may be involved in the calcium oxalate crystallization through interaction with NC. The role of ascorbic acid in the formation of urinary stones should be reappraised for its association in the redox reaction, with resultant protein digestion in the presence of copper ions.

Anticancer activity evaluation of the solanum glycoalkaloid solamargine. Triggering apoptosis in human hepatoma cells

Solamargine, an herbal and molluscicidal medicine derived from Solanum incanum, is a steroidal alkaloid glycoside. To characterize the anticancer mechanism of solamargine on human hepatoma cells (Hep3B), changes of cell morphology, DNA content, and gene expression of cells after solamargine treatment were studied. The appearance in solamargine-treated cells of chromatin condensation, DNA fragmentation, and a sub-G(1) peak in a DNA histogram suggests that solamargine induces cell death by apoptosis. The maximum number of dead Hep3B cells was detected within 2 hr of incubation with constant concentrations of solamargine, and no further cell death was observed after an extended incubation with solamargine, indicating that the action of solamargine was irreversible. To determine the susceptibility of cell phases to solamargine-mediated apoptosis, Hep3B cells were synchronized at defined cell cycles by cyclosporin A, colchicine, and genistein, followed by solamargine treatment. The IC(50) values of solamargine for control, G(0)/G(1)-, M-, and G(2)/M-synchronized Hep3B cells were 5.0, > 10, 3.7, and 3.1 microg/mL, implying that cells in the G(2)/M phases are relatively susceptible to solamargine-mediated apoptosis. In addition, a parallel up-regulation of tumor necrosis factor receptor (TNFR)-I and -II on Hep3B cells was detected after solamargine treatment, and the solamargine-mediated cytotoxicity could be neutralized with either TNFR-I or -II specific antibody. Therefore, these results reveal that the actions of TNFR-I and -II on Hep3B cells may be independent, and both are involved in the mechanism of solamargine-mediated apoptosis.

Activity-guided isolation of constituents of Cerbera manghas with antiproliferative and antiestrogenic activities

Two new cardenolides, (-)-14-hydroxy-3beta-(3-O-methyl-6-deoxy-alpha-L-rhamnosyl)-11a lpha, 12alpha-epoxy-(5beta,14beta,17betaH)-card-20 (22)-enolide (1), (-)-14-hydroxy-3beta-(3-O-methyl-6-deoxy-alpha-L-glucopyranosyl)-11al pha,12alpha-epoxy-(5beta,14beta,17betaH)-card -20(22)-enolide (2), and a known cardenolide, (-)-17beta-neriifolin (3), were isolated from the roots of Cerbera manghas as antiproliferative and antiestrogenic principles when evaluated against a human colon cancer cell line (Col2) and the Ishikawa cell line, respectively. Two known lignans, (-)-olivil (4) and (-)-cycloolivil (5), were also isolated but were inactive in the assay systems used.

Bioactive constituents of Thuja occidentalis

An ethyl acetate-soluble extract of the combined leaves and twigs of Thuja occidentalis was found to inhibit 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ornithine decarboxylase (ODC) in cultured mouse epidermal ME 308 cells. Bioassay-guided fractionation of this extract led to the isolation of six active constituents (1-6), namely, (+)-7-oxo-13-epi-pimara-14,15-dien-18-oic acid (1), (+)-7-oxo-13-epi-pimara-8,15-dien-18-oic acid (2), (+)-isopimaric acid (3), (1S,2S,3R)-(+)-isopicrodeoxypodophyllotoxin (4), (-)-deoxypodophyllotoxin (5), and (-)-deoxypodorhizone (6). Compounds 1 and 4 are new natural products, and their structures and stereochemistry were determined using spectroscopic methods. Compounds 1-6 were evaluated for inhibition of the transformation of murine epidermal JB6 cells, inhibition of ornithine decarboxylase induction with murine epidermal ME 308 cells, and cytotoxic activity against KB cells.

Quantitative determination of the expression of xeroderma pigmentosum F gene in human nonmelanoma skin cancers

Nonmelanoma skin cancers (NMSC) has been evidenced with an impaired function in nucleotide excision repair (NER). However, malfunction of NER elements in NMSC has not been identified. Xeroderma pigmentosum F (XPF) is an essential subunit in NER and functions as a 5'-incision enzyme when repairing damaged DNA. So far, neither XPF's protein nor antibody is commercially available. To explore the expression of XPF in NMSC, the gene was determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR). All the designed primers specifically amplified XPF cDNA as demonstrated by nested PCR, and one set of the primers was mimic constructed to form a controlled cDNA for the semiquantification of XPF gene in NMSC. The results indicated that the quantities of XPF expression of BCC and SCC specimens were approximately 57.0 and 76.4% less than that of normal skins, respectively. This paper indicates that the decrease expression of XPF gene may be one of mechanisms for impaired NER in NMSC, and the feasible and quantitative primers used in the experiments may explore the study of XPF in etiology of carcinogenesis.

Low molecular weight protamine: a potent but nontoxic antagonist to heparin/low molecular weight protamine

To avoid bleeding complications, protamine is routinely used after cardiovascular surgery to neutralize the anticoagulant function of heparin. However, its clinical use is associated with adverse and sometimes fatal reactions. Based on literature review of the mechanism of heparin neutralization and protamine induced immunologic toxicity, we propose the following hypothesis: If a chain shortened low molecular weight protamine (LMWP) containing the heparin neutralizing domain could be derived from native protamine, it could be a potent and yet nontoxic heparin antagonist. In this study, we present results to validate this hypothesis. LMWP fragments containing an intact arginine sequence and an average molecular weight of approximately 1,100 daltons were successfully prepared by enzymatic digestion of protamine with thermolysin. In vitro studies show that such LMWP fragments completely neutralized the anticoagulant functions of heparin and LMWH, based on the anti-Xa chromogenic and aPTT clotting time assays. In vivo results reveal that although injection of protamine to mice led to obvious production of anti-protamine antibodies, injection of LMWP did not elicit any detectable immunogenic responses. In addition, these LMWP fragments exhibited a markedly reduced antigenicity and cross-reactivity toward the mice anti-protamine antibodies.

Aromatase inhibitors from Isodon excisus var. coreanus

The diethyl ether extract of Isodon excisus var. coreanus exhibited significant inhibitory activity in aromatase assay. Bioactivity-guided fractionation of the extract led to the isolation of three active compounds: inflexin (ent-1alpha-hydroxy-3beta,6a-diacetoxykaur-16-en-11,15-dione ) (1), ursolic acid (2), and ursolic acid 3-O-acetate (3).

The upstream regulation of p38 mitogen-activated protein kinase phosphorylation by arachidonic acid in rat neutrophils

The signal transduction pathways activated by arachidonic acid that lead to p38 mitogen-activated protein kinase (MAPK) activation in neutrophils remains unclear. In this study, selective inhibitors of several signalling pathways were utilized to investigate the mechanisms of activation of p38 MAPK by arachidonic acid in rat neutrophils. Stimulation of p38 MAPK phosphorylation by arachidonic acid and its trifluoromethyl ketone analogue AACOCF3 was transient, peaking at 1 min, and was concentration-dependent. Arachidonic acid-stimulated p38 MAPK phosphorylation was attenuated in cells pretreated with the Gi/o inhibitor (pertussis toxin), but not with the dual cyclooxygenase/lipoxygenase inhibitor (BW755C) or the leukotriene biosynthesis inhibitor (MK886). Tyrosine kinase inhibitor (genistein), but not the extracellular signal-regulated kinase kinase inhibitors (PD98059 and U0126), attenuated the phosphorylation of p38 MAPK by arachidonic acid. Phosphoinositide 3-kinase inhibitors (wortmannin and LY294002) did not affect the arachidonic acid-induced response. After pretreatment of the cells with protein kinase C inhibitors (Gö6976, Gö6983 and GF109203X), only Gö6976 significantly attenuated the phosphorylation of p38 MAPK by arachidonic acid. In addition, phosphorylation of p38 MAPK by arachidonic acid was greatly attenuated by the phospholipase C inhibitor (U73122) and the Ca2+ chelator BAPTA ((1,2-bis-o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid), but not altered by the nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester. Arachidonic acid did not cause an increase in cellular cyclic GMP level. This study revealed the involvement of pertussis toxin-sensitive G protein, non-receptor tyrosine kinase, phospholipase C/Ca2+, and probably Ca2+-dependent protein kinase C in arachidonic acid-stimulated p38 MAPK activation.

Activation of p38 mitogen-activated protein kinase by formyl-methionyl-leucyl-phenylalanine in rat neutrophils

The signaling pathways leading to p38 mitogen-activated protein kinase (MAPK) activation in formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated rat neutrophils were examined. Immunoblot analysis with antibodies against a phosphorylated form of p38 MAPK showed that fMLP-stimulated p38 MAPK activation was dependent on a pertussis toxin-sensitive G protein. Two phosphatidylinositol 3-kinase inhibitors, wortmannin and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), did not affect the p38 MAPK activation. Phosphorylation of p38 MAPK was concentration dependently attenuated by a tyrosine kinase inhibitor, genistein, and by a Ca(2+)-dependent protein kinase C inhibitor, 13-cyanoethyl-12-methyl-6,7,12,13-tetrahydroindolo[2,3-a]pyrrolo[3 , 4-c]carbazole-7-one (Gö6976). However, the protein kinase C inhibitors with a broader spectrum, 2-[1-(3-dimethylaminopropyl)-5-methoxy-1H-indol-3-yl]-3-(1H-indol-3-y l)-maleimide (Gö6983) and 2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)-maleimi de (GF109203X), had no inhibitory effect. fMLP-stimulated p38 MAPK phosphorylation was also reduced in cells pretreated with a phospholipase C inhibitor, 1-[6-((17beta-3-methoxyestra-1,3, 5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione (U73122), or preloaded with an intracellular Ca(2+) chelator, 1, 2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA). We conclude that phosphorylation of p38 MAPK by fMLP stimulation in rat neutrophils is dependent on G(i/o) protein, nonreceptor tyrosine kinase, phospholipase C/Ca(2+), and probably Ca(2+)-dependent protein kinase C pathways.

Absolute configuration of novel bioactive flavonoids from Tephrosia purpurea

[structure: see text] Three novel flavonoids, (+)-tephrorins A (1) and B (2) and (+)-tephrosone (3), were isolated from Tephrosia purpurea. Their structures were elucidated by NMR spectral analysis, and their absolute configurations were determined by Mosher ester methodology. Compounds 1 and 2 are flavanones containing an unusual tetrahydrofuran moiety. Compounds 1-3 were evaluated for their potential cancer chemopreventive properties using a cell-based quinone reductase induction assay.

Electrochemical assay of plasminogen activators in plasma using polyion-sensitive membrane electrode detection

Two relatively simple electrochemical assay methods suitable for the measurement of plasminogen activators (including urokinase (u-PA), streptokinase (SK), and tissue plasminogen activator (t-PA)) in plasma samples are described. In one approach, the initial rate of decrease in the potentiometric response of a polycation-sensitive membrane electrode toward protamine is monitored after addition of a preincubated reaction mixture containing the sample and exogenous plasminogen. The plasmin formed from plasminogen by the activators catalyzes the decomposition of the arginine-rich protamine substrate, yielding smaller polycationic fragments that are not sensed by the electrode. Alternately, the sample, plasminogen, and protamine can be incubated together, and the remaining protamine in this reaction mixture can be measured at a fixed point in time by placing the electrode into the mixture and recording the electromotive force response. Working curves found with both methods for plasma samples spiked with varying levels of the activators cover the expected therapeutic activity ranges found in the plasma of patients treated with these "clot-busting" drugs.

Proinflammatory cytokines and fibrinolytic enzymes in tuberculous and malignant pleural effusions

OBJECTIVES

To measure tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in pleural effusions caused by tuberculosis (TB) and malignancy and their relationship with plasminogen activator inhibitor type I (PAI-1) and tissue type plasminogen activator (tPA), and to compare the differences between tuberculous and malignant pleural effusions. In addition, the relationship between the effusion levels of these parameters and the development of residual pleural thickening was evaluated in the patients with tuberculous pleurisy.

DESIGN

Prospective study.

MATERIALS AND METHODS

TNF-alpha, IL-1beta, PAI-1, and tPA were measured simultaneously in blood and pleural fluid using an enzyme-linked immunosorbent assay in 33 patients with tuberculous and in 30 patients with malignant pleural effusions. Residual pleural thickening was measured and defined as a pleural thickness of >/= 10 mm found on chest radiographs at the completion of anti-TB chemotherapy in tuberculous pleurisy patients.

RESULTS

In both groups, the levels of proinflammatory cytokines and fibrinolytic enzymes were significantly higher in pleural fluid than in blood. The levels of TNF-alpha and PAI-1 were significantly higher in tuberculous than in malignant effusions. In contrast, malignant pleural fluid had significantly higher values of tPA than did tuberculous pleural fluid. In tuberculous effusions, the values of PAI-1 and the PAI-1/tPA ratio correlated positively and the levels of tPA correlated negatively with those of TNF-alpha and IL-1beta. In malignant pleural fluid, positive correlations were found between the values of proinflammatory cytokines (TNF-alpha and IL-1beta) and PAI-1. Residual pleural thickening was found in 9 of 33 patients (27. 3%) with tuberculous pleurisy. The pleural fluid values of TNF-alpha, IL-1beta, and PAI-1 were significantly higher and the concentrations of tPA were significantly lower in tuberculous pleurisy patients with residual pleural thickening.

CONCLUSIONS

Compared to malignant pleural effusion, fibrinolytic activity in pleural fluid was reduced in tuberculous effusion. Pleural inflammation caused by TB may enhance the release of proinflammatory cytokines, particularly TNF-alpha, which subsequently may increase PAI-1 and decrease tPA in pleural fluid. The imbalance of PAI-1 and tPA in pleural space may lead to fibrin deposition and pleural thickening.

Complete nucleotide sequence of pig (Sus scrofa) mitochondrial genome and dating evolutionary divergence within Artiodactyla

The complete nucleotide sequence of the pig (Sus scrofa) mitochondrial genome, containing 16613bp, is presented in this report. The genome is not a specific length because of the presence of the variable numbers of tandem repeats, 5'-CGTGCGTACA in the displacement loop (D-loop). Genes responsible for 12S and 16S rRNAs, 22 tRNAs, and 13 protein-coding regions are found. The genome carries very few intergenic nucleotides with several instances of overlap between protein-coding or tRNA genes, except in the D-loop region. For evaluating the possible evolutionary relationships between Artiodactyla and Cetacea, the nucleotide substitutions and amino acid sequences of 13 protein-coding genes were aligned by pairwise comparisons of the pig, cow, and fin whale. By comparing these sequences, we suggest that there is a closer relationship between the pig and cow than that between either of these species and fin whale. In addition, the accumulation of transversions and gaps in pig 12S and 16S rRNA genes was compared with that in other eutherian species, including cow, fin whale, human, horse, and harbor seal. The results also reveal a close phylogenetic relationship between pig and cow, as compared to fin whale and others. Thus, according to the sequence differences of mitochondrial rRNA genes in eutherian species, the evolutionary separation of pig and cow occurred about 53-60 million years ago.

Examination of the signal transduction pathways leading to activation of extracellular signal-regulated kinase by formyl-methionyl-leucyl-phenylalanine in rat neutrophils

The signaling pathways leading to extracellular signal-regulated kinase (ERK) activation in formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated rat neutrophils were examined. fMLP-stimulated ERK activation based on immunoblot analysis with antibodies against the phosphorylation form of ERK was attenuated by the pretreatment of cells with pertussis toxin but not with a dual cyclo-oxygenase/lipoxygenase inhibitor BW755C. Exposure of cells to the tyrosine kinase inhibitor genistein, phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002, or protein kinase C (PKC) inhibitors Gö6976, Gö6983, and GF109203X inhibited fMLP-stimulated ERK phosphorylation in a concentration-dependent manner. In addition, both the phospholipase C (PLC) inhibitor U73122 and the Ca2+ chelator BAPTA attenuated ERK activation. These results indicate that G(i/o) protein, tyrosine kinase, P13K, PKC, and PLC/Ca2+, but not arachidonate metabolites, act upstream of fMLP-stimulated ERK activation.

A novel function of emodin: enhancement of the nucleotide excision repair of UV- and cisplatin-induced DNA damage in human cells

Nucleotide excision repair (NER) is the main pathway by which mammalian cells remove carcinogenic DNA lesions caused by UV light and many other common mutagens. To explore the effect of emodin on NER, its influence on the repair of UV- and cisplatin-induced DNA damage in human fibroblast cells (WI38) was evaluated. Emodin increased unscheduled DNA synthesis (UDS) of UV-treated cells and reduced cisplatin-induced DNA adducts in WI38 in a concentration-dependent manner, indicating that emodin might promote NER capability in cells. The resultant NER complex is a cooperative assembly of XPF, ERCC1, XPA, RPA, and XPG subunits. The gene regulations of the subunits after emodin treatment were determined by reverse transcription-polymerase chain reaction (RT-PCR) using specific primers. Among the subunits, the expression of ERCC1 in WI38 cells was up-regulated significantly after emodin treatment. All other expressions remained essentially unchanged. In addition, calcium influx in WI38 was increased in proportion to the concentration of emodin. Since UV-induced NER is Ca2+ dependent, elevation of calcium influx may be another mechanism by which emodin facilitates DNA repair. In conclusion, emodin can increase the repair of UV- and cisplatin-induced DNA damage in human cells, and elevated ERCC1 gene expression and Ca2+-mediated DNA repair processes may be involved in the repair mechanism of emodin.

2-Hydroxymethyl-1-naphthol diacetate (TAC) suppresses the superoxide anion generation in rat neutrophils

We have investigated the inhibitory effect of 2-hydroxymethyl-1-naphthol diacetate (TAC) on the respiratory burst of rat neutrophils and the underlying mechanism of action was also assessed in this study. TAC caused concentration-related inhibition of the formylmethionyl-leucyl-phenylalanine (fMLP) plus dihydrocytochalasin B (CB)- and phorbol 12-myristate 13-acetate (PMA)-induced superoxide anion (O2*-) generation (IC50 10.2+/-2.3 and 14.1+/-2.4 microM, respectively) and O2 consumption (IC50 9.6+/-2.9 and 13.3+/-2.7 microM, respectively) of neutrophils. TAC did not scavenge the generated O2*- during dihydroxyfumaric acid autoxidation. TAC inhibited both the transient elevation of [Ca2+]i in the presence or absence of [Ca2+]o (IC50 75.9+/-8.9 and 84.7+/-7.9 microM, respectively) and the generation of inositol trisphosphate (IP3) (IC50 72.0+/-9.7 microM) in response to fMLP. Cytosolic phospholipase C (PLC) activity was also reduced by TAC at a same range of concentrations. The PMA-induced PKC-beta associated to membrane was attenuated by TAC (about 80% inhibition at 30 microM). Upon exposure to fMLP, the cellular cyclic AMP level was decreased in neutrophils pretreated with TAC. TAC attenuated fMLP-induced phosphorylation of mitogen-activated protein kinase (MAPK) p42/44 (IC50 17.4+/-1.7 microM), but not p38. The cellular formation of phosphatidic acid (PA) and, in the presence of ethanol, phosphatidylethanol (PEt) induced by fMLP was inhibited by TAC in a concentration-dependent manner (IC50 25.4+/-2.4 and 25.9+/-1.4 microM, respectively). TAC had no effect on the O2*- generation of PMA-stimulated and arachidonic acid (AA)-stimulated NADPH oxidase preparations. However, TAC caused concentration-related decrease of the membrane associated p47phoX in PMA-stimulated neutrophils (about 80% inhibition at 30 microM). We conclude that inhibition by TAC of the neutrophil respiratory burst is probably attributable to the blockade of the p42/44 MAPK and phospholipase D (PLD) pathways, the membrane translocation of PKC, and to the failure in assembly of a functional NADPH oxidase complex. Blockade of the PLC pathway by TAC probably plays a minor role.

Electrochemical sensors for polyionic macromolecules: development and applications in pharmaceutical research

The first electrochemical sensors responsive towards polyionic heparin and protamine - two clinically important polymeric drugs - have been fully developed. The response mechanism of these sensors has been completely elucidated. As well as their significance in measuring blood heparin levels in clinically relevant concentration ranges, these polyion sensors could also find broad applications in pharmaceutical research, such as in the study of the binding events between heparin (or protamine) and other polycationic (or polyanionic) macromolecules. In addition, the sensors could be employed in the design of blood assays for a range of clinically important proteases and their inhibitors by utilizing either protamine or specially designed synthetic polypeptides as the substrates

Inhibition by magnolol of formylmethionyl-leucyl-phenyl alanine-induced respiratory burst in rat neutrophils

The influence of the plant product magnolol on neutrophil superoxide anion (O2-*) generation has been investigated in the rat. Intraperitoneal injection of magnolol (30mg kg(-1)) significantly inhibited the formylmethionyl-leucyl-phenylalanine (fMLP)-induced respiratory burst in rat whole blood ex-vivo. Magnolol also inhibited the 02-* generation with an IC50 (concentration resulting in 50% inhibition) of 15.4+/-1.6 microM and O2 consumption in rat neutrophils in-vitro. Magnolol weakly inhibited the O2-* generation in the xanthine-xanthine oxidase system, decreased cellular cyclic AMP level and had no effect on cyclic GMP levels. It weakly inhibited neutrophil cytosolic protein kinase C activity but did not alter porcine heart protein kinase A activity. Magnolol attenuated fMLP-induced protein tyrosine phosphorylation with an IC50 of 24.0+/-1.9 microM and the phosphorylation of mitogen-activated protein kinase p42/44 with an IC50 of 28.5+/-4.5 microM. However, magnolol alone activated neutrophil phospholipase D activity as determined by the formation of phosphatidic acid and phosphatidyl-ethanol in the presence of ethanol. In the presence of NADPH, the arachidonate-activated NADPH oxidase activity in a cell-free system was weakly suppressed by magnolol. These results suggest that the inhibition of respiratory burst in fMLP-activated neutrophils by magnolol is probably attributable mainly to the attenuation of protein tyrosine phosphorylation and p42/44 mitogen-activated protein kinase activation, and partly to the suppression of protein kinase C and NADPH oxidase activities.

Flavonoid constituents of Chorizanthe diffusa with potential cancer chemopreventive activity

An ethyl acetate-soluble extract of Chorizanthe diffusa was found to exhibit significant antioxidant activity, as judged by scavenging stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced free radical formation with cultured HL-60 cells. Bioassay-directed fractionation of this extract using the DPPH antioxidant assay as a monitor led to the isolation of five structurally related flavonoids (1-5), including the novel compound 5,8,3',4',5'-pentahydroxy-3, 7-dimethoxyflavone (1). Isolates 1-5 demonstrated varying degrees of antioxidant or antimutagenic activity. Two of the compounds, 5,7,3', 4'-tetrahydroxy-3-methoxyflavone (2) and quercetin (4), were subsequently found to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary organ culture model. Inhibitory activity of this type is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis.

Space changes after premature loss of the mandibular primary first molar: a longitudinal study

The purpose of this study was to evaluate the space changes after premature loss of the primary mandibular first molar. Twenty-one children (12 boys and 9 girls), with premature loss of the primary mandibular first molar, were selected from the children's dental clinic for this study. The age ranged from 5.1 to 7.2 years with an average of 6 years and 11 months. Mandibular study casts were made from alginate impression for each initial examination and a follow-up examination eight months later. Four measurements including D+E (first and second primary molars) space, arch width, arch length and arch perimeter were tested for comparisons between the initial examination and the follow-up examination eight months later. The D+E space of intact primary molars served as a control. The results showed that the D+E space on the extraction side after the follow-up examination eight months later was significantly shorter than the control side (p = 0.025) and less than the initial D+E space (p < 0.001). However, there were no significant differences on arch width, arch length, and arch perimeter between the initial examination and the follow-up examination eight months later (p > 0.05). It is concluded that the space change after the eruption of the first permanent molar in the mandible is mostly distal movement of the primary cuspid during the early stage of premature loss of the primary first molar.