Search PubMed⌕ Search

Biomedical subjects

W W Lin

Publications and source records attributed to W W Lin.

At least 19 recordsLinked to original sources
PubMed2004

Decoy receptor 3 (DcR3) induces osteoclast formation from monocyte/macrophage lineage precursor cells.

Recent evidence indicates that the decoy receptor 3 (DcR3) of the TNF receptor superfamily, which initially though prevents cytokine responses of FasL, LIGHT and TL1A by binding and neutralization, can modulate monocyte function through reverse signaling. We show in this work that DcR3 can induce osteoclast formation from human monocytes, murine RAW264.7 macrophages, and bone marrow cells. DcR3-differentiated cells exhibit characteristics unique for osteoclasts, including polynuclear giant morphology, bone resorption, TRAP, CD51/61, and MMP-9 expression. Consistent with the abrogation of osteoclastogenic effect of DcR3 by TNFR-Fc, DcR3 treatment can induce osteoclastogenic cytokine TNF-alpha release through ERK and p38 MAPK signaling pathways. We conclude that DcR3 via coupling reverse signaling of ERK and p38 MAPK and stimulating TNF-alpha synthesis is a critical regulator of osteoclast formation. This action of DcR3 might play an important role in significant osteoclastic activity in osteolytic bone metastases.

Acid Phosphatase↗
PubMed2003

Coagulation of humic-kaolin-PACI aggregates.

Water treatment residual flocs are fractal-like aggregates made of many initial aggregates. We investigated in this study the coagulation dynamics for the humic-mineral-polyaluminium chloride (PACI) aggregates using small-angle light scattering techniques and the free-settling test. In contrast to reports in the literature, the presence of humic acid did not lead to a loose floc. Not only the time evolution of the coagulation dynamics, but also the final floc characteristics are only mildly affected by the humic acid. However, the strength of the formed floc does decline with humic acid, which leads to a turbid supernatant with high level of organics.

Aluminum Hydroxide↗
PubMed2003

Observations of blanket characteristics in full-scale floc blanket clarifiers.

We monitored the changes in concentrations, zeta potentials, sizes and capillary suction times of the solids flocs in the clarified water from eight floc blanket clarifiers of PingTsan Water Works of Taiwan Water Supply Company with low (< 10 NTU) and high (> 100 NTU) turbidity raw water. For the former, one-stage coagulation-sedimentation treatment was adopted which yielded a rather unstable blanket. Complete washout was noticeable when the PACl dosage was insufficient. On the treatment of high-turbidity raw water, on the other hand, the Works adopted the combined treatment process, that is, the raw water was first coagulated and settled in a pre-sedimentation tank, afterwards, its effluent was coagulated again and clarified in the clarifiers. The resulting flocs could form a networked blanket that was relatively stable to the shock load in raw water turbidity.

Bioreactors↗
PubMed2001

Ceramide inhibits lipopolysaccharide-mediated nitric oxide synthase and cyclooxygenase-2 induction in macrophages: effects on protein kinases and transcription factors.

The goal of this study was to elucidate whether triggering the sphingomyelin pathway modulates LPS-initiated responses. For this purpose we investigated the effects of N-acetylsphingosine (C(2)-ceramide) on LPS-induced production of NO and PGE(2) in murine RAW 264.7 macrophages and explored the signaling pathways involved. We found that within a range of 10-50 microM, C(2)-ceramide inhibited LPS-elicited NO synthase and cyclooxygenase-2 induction accompanied by a reduction in NO and PGE(2) formation. By contrast, a structural analog of C(2)-ceramide that does not elicit functional activity, C(2)-dihydroceramide, did not affect the LPS response. The nuclear translocation and DNA binding study revealed that ceramide can inhibit LPS-induced NF-kappaB and AP-1 activation. The immunocomplex kinase assay indicated that IkappaB kinase activity stimulated by LPS was inhibited by ceramide, which concomitantly reduced the IkappaBalpha degradation caused by LPS within 1-6 h. In concert with the decreased cytosolic p65 protein level, LPS treatment resulted in rapid nuclear accumulation of NF-kappaB subunit p65 and its association with the cAMP-responsive element binding protein. Ceramide coaddition inhibited all the LPS responses. In addition, LPS-induced PKC and p38 mitogen-activated protein kinase activation were overcome by ceramide. In conclusion, we suggest that ceramide inhibition of LPS-mediated induction of inducible NO synthase and cyclooxygenase-2 is due to reduction of the activation of NF-kappaB and AP-1, which might result from ceramide's inhibition of LPS-stimulated IkappaB kinase, p38 mitogen-activated protein kinase, and protein kinase C.

Active Transport, Cell Nucleus↗
PubMed2001

An improved and easy method for the preparation of 2,2-disubstituted 1-nitroalkenes.

Reactions of ketones 1, nitromethane 2, and catalytic amount of piperidine 3 in the presence of mercaptan 6 generate beta-nitroalkyl sulfides 7-9. At 0 degrees C and by the use of dichloromethane as solvent, beta-nitroalkyl sulfides 7-9 can be oxidized by m-chloroperoxybenzoic acid (m-CPBA) 10 to generate beta-nitroalkyl sulfoxides 11-13 and undergo elimination in carbon tetrachloride solution to produce medium to high yield of 2,2-disubstituted 1-nitroalkenes 5. The irreversibility of the synthetic mechanism not only can overcome the reversibility of the Henry reaction in the synthesis of 2,2-disubstituted 1-nitroalkenes 5 but also can generate the major products "exo-nitro olefins"5c-e when cyclic ketones 1c-e were used. Under similar conditions, medium to high yield of 5-substituted-2-nitromethyl-2-phenylthioadamantane 17 also can be prepared from the reaction of 5-substituted-2-adamantanones 15, nitromethane 2, piperidine 3, thiophenol 6a. The intermediate17 can be oxidized by m-CPBA 10 in dichloromethane solution and then undergo elimination at room temperature or can be dissolved in solvent, coated on silica gel, and then heated at 90-100 degrees C to generate 5-substituted-2-nitromethyleneadamantane 16.

Journal Article↗
PubMed2001

Effects of cannabinoids on LPS-stimulated inflammatory mediator release from macrophages: involvement of eicosanoids.

Delta(9)-Tetrahydrocannabinol (Delta(9)-THC) is the major psychoactive component of marijuana and elicits pharmacological actions via cannabinoid receptors. Anandamide (AEA) and 2-arachidonoyl-glycerol (2-AG) are endogenous ligands for cannabinoid receptors, which because of their structural similarities to arachidonic acid (AA), AEA, and 2-AG could serve as substrates for lipoxygenases and cyclooxygenases (COXs) that metabolize polyunsaturated fatty acids to potent bioactive molecules. In this study, we have compared the effects of Delta(9)-THC, AEA, 2-AG, and another cannabinoid agonist, indomethacin morpholinylamide (IMMA), on lipopolysaccharide (LPS)-induced NO, IL-6, and PGE(2) release from J774 macrophages. Delta(9)-THC, IMMA, and AEA diminish LPS-induced NO and IL-6 production in a concentration-dependent manner. 2-AG inhibits the production of IL-6 but slightly increases iNOS-dependent NO production. Delta(9)-THC and IMMA also inhibit LPS-induced PGE(2) production and COX-2 induction, while AEA and 2-AG have no effects. These discrepant results of 2-AG on iNOS and COX-2 induction might be due to its bioactive metabolites, AA and PGE(2), whose incubation cause the potentiation of both iNOS and COX-2 induction. On the contrary, the AEA metabolite, PGE(2)-ethanolamide, influences neither the LPS-induced NO nor IL-6 production. Taken together, direct cannabinoid receptor activation leads to anti-inflammatory action via inhibition of macrophage function. The endogenous cannabinoid, 2-AG, also serves as a substrate for COX-catalyzing PGE(2) production, which in turn modulates the action of CB2.

Animals↗
PubMed2001

Diagnosis and treatment of the azoospermic patient.

With the advent of intracytoplasmic injection, the management of azoospermia has become ever more important. Gametic manipulation to produce biological offspring is not feasible unless sperm from the azoospermic male patient is obtainable. This article provides an overview of the diagnosis and treatment of azoospermia.

Genitalia, Male↗
PubMed2001

Increased chromosome X, Y, and 18 nondisjunction in sperm from infertile patients that were identified as normal by strict morphology: implication for intracytoplasmic sperm injection.

OBJECTIVE: To determine the incidence of nondisjunction for chromosomes X, Y, and 18 using fluorescence in situ hybridization (FISH) on morphologically normal sperm from infertile men who are candidates for ICSI. DESIGN: After standard hematoxylin staining, sperm with normal morphology were identified using Kruger's strict morphology criteria. The location of each normal-appearing sperm was recorded using an electronic microstage locator. Slides were subsequently subjected to FISH for detection of chromosomes X, Y, and 18 (control probe). Nuclei were relocated and analyzed under the fluorescent microscope. SETTING: University-affiliated IVF and intracytoplasmic sperm injection program. PATIENT(S): Men classified as infertile on the basis of abnormal strict morphology (<4% by Kruger's criteria). For controls, normal fertile men (n=6) were also analyzed. INTERVENTION(S): Semen smears were obtained retrospectively from infertile (n=8) and fertile (n=6) men. MAIN OUTCOME MEASURE(S): Ploidy of each cell was determined according to the number of signals detected for each probe. RESULT(S): Approximately 100-150 morphologically normal sperm were identified and located in each case. Subsequent FISH analysis of these normal sperm showed aneuploidy to range from 1.8% to 5.5% in the infertile group as compared with 0 to 2.6% among the control fertile group. Statistically significant differences in the incidence of aneuploidy for the sex chromosomes as well as for all three (X, Y, and 18) chromosomes was observed. CONCLUSION(S): Although 95% to 98% of the sperm were found to be normal for X, Y, and 18, our findings show that infertile couples undergoing ICSI are likely to be at an increased risk for having a genetically abnormal conceptus as compared with the fertile controls. These results demonstrate that normal morphology is not an absolute indicator for the selection of genetically normal sperm. Hence, observed pregnancy failures among ICSI patients may in part be due to the selection of aneuploid sperm.

Adult↗
PubMed2001

PKC- and ERK-dependent activation of I kappa B kinase by lipopolysaccharide in macrophages: enhancement by P2Y receptor-mediated CaMK activation.

1. Although accumulating studies have identified I kappa B kinase (IKK) to be essential for controlling NF-kappa B activity in response to several cytokines, the upstream kinases that control IKK activity are still not completely known. We have previously reported that G protein-coupled P2Y(6) receptor activation by UTP potentiates lipopolysaccharide (LPS)-induced I kappa B phosphorylation and degradation, and NF-kappa B activation in J774 macrophages. In this study, we investigated the upstream kinases for IKK activation by UTP and LPS. 2. In murine J774 macrophages, LPS-induced NF-kappa B activation was inhibited by the presence of PDTC, D609, Ro 31-8220, PD 098059 and SB 203580. 3. Accompanying NF-kappa B activation, LPS induced I kappa B degradation and IKK activation were reduced by PDTC, D609, Ro 31-8220 and PD 098059, but not by SB 203580. 4. Although UTP itself slightly induced IKK activation, this response was synergistic with LPS. BAPTA/AM and KN-93 (a calcium/calmodulin-dependent protein kinase (CaMK) inhibitor) attenuated UTP- but not LPS-stimulated IKK activity. Synergistic IKK activation between LPS and thapsigargin was further demonstrated in peritoneal macrophages. 5. LPS and UTP co-stimulation additively increased p65 NF-kappa B phosphorylation. In vitro kinase assays revealed that LPS and UTP induced extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase activation were respectively inhibited by PD098059 and SB 203580. 6. Taken together, we demonstration that Gq protein-coupled P2Y(6) receptor activation can potentiate LPS-stimulated IKK activity. While PKC and ERK participate in IKK activation by LPS and UTP, the phosphatidylinositide-phospholipase C-dependent activation of CaMK plays a major role in UTP potentiation of the LPS response.

Animals↗
PubMed2001

Dopamine D2 receptor gene (DRD2) is associated with alcoholism with conduct disorder.

This study examined whether there is evidence for an association between alcoholism with conduct disorder and alleles of the TaqI A and TaqI B polymorphisms, both individually and as haplotypes, at the dopamine D2 receptor gene (DRD2). We studied 182 Han Chinese subjects, including 34 alcoholics with conduct disorder, 63 alcoholics without conduct disorder, and 85 nonalcoholics. Alcohol dependence and conduct disorder were defined according to DSM-III-R criteria. Significant associations were observed between TaqI A and TaqI B at the DRD2 locus, tested individually and as haplotypes, and alcoholism with conduct disorder. Our results suggested that DRD2 might be associated with conduct disorder or a predisposition to both conduct disorder and alcoholism. However, this needs to be further investigated by examining the differences among conduct disorder with alcoholism, conduct disorder only, and controls for the TaqI A and B system at DRD2.

Adult↗
PubMed2001

Involvement of protein kinases in the potentiation of lipopolysaccharide-induced inflammatory mediator formation by thapsigargin in peritoneal macrophages.

We have explored the regulatory roles played by Ca2+-dependent signaling on lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 (IL-6) release in mouse peritoneal macrophages. To elevate intracellular Ca2+, we used thapsigargin (TG) and UTP. Although LPS alone cannot stimulate NO synthesis, co-addition with TG, which sustainably increased [Ca2+]i, resulted in NO release. UTP, via acting on P2Y6 receptors, can stimulate phosphoinositide (PI) turnover and transient [Ca2+]i increase, however, it did not possess the NO priming effect. LPS alone triggered the release of PGE2, TNF-alpha, and IL-6; all of which were potentiated by the presence of TG, but not of UTP. The stimulatory effect of LPS plus TG on NO release was inhibited by the presence of Ro 31-8220, Go6976, KN-93, PD 098059, or SB 203580, and abolished by BAPTA/AM and nuclear factor kappaB (NF-kappaB) inhibitor, PDTC. PGE2, TNF-alpha, and IL-6 release by LPS alone were attenuated by Ro 31-8220, Go6976, PD 098059, SB 203580, and PDTC. Using L-NAME, soluble TNF-alpha receptor, IL-6 antibody, NS-398, and indomethacin, we performed experiments to understand the cross-regulation by the four mediators. The results revealed that TNF-alpha up-regulated NO, PGE2, and IL-6 synthesis; PGE2 up-regulated NO, but down-regulated TNF-alpha synthesis; and PGE2 and IL-6 mutually up-regulated reciprocally. Taken together, murine peritoneal macrophages required a sustained [Ca2+]i increase, which proceeds after TG, but not UTP, stimulation, to enhance LPS-mediated release of inflammatory mediators, particularly for NO induction. Activation of PKC-, ERK-, and p38 MAPK-dependent signaling also are essential for LPS action. The positive regulatory interactions among these mediators might amplify the inflammatory response caused by endotoxin.

Adjuvants, Immunologic↗
PubMed2000

Basal cPLA(2) phosphorylation is sufficient for Ca(2+)-induced full activation of cPLA(2) in A549 epithelial cells.

The release of [(3)H] arachidonic acid (AA) and its connection with the triggering of the MAP kinase cascade were studied in the human A549 epithelial cell line upon stimulation with thapsigargin. Thapsigargin can increase AA release along with the increase of intracellular calcium concentration, phosphorylation, and activation of extracellular regulated kinase (ERK) and cytosolic phospholipase A(2) (cPLA(2)). Both ERK and cPLA(2) phosphorylation in response to thapsigargin were inhibited by PD 98059, a specific inhibitor of MAP kinase kinase of the ERK group (MEK), and EGTA. cPLA(2) phosphorylation was not affected by Ro 31-8220 (an inhibitor of all PKC isoforms) or LY 379196 (a PKCbeta selective inhibitor), while both of them indeed attenuated ERK activation. On the other hand, rottlerin (the selective PKCdelta inhibitor), SB 203580 (the selective p38 MAPK inhibitor), and wortmannin (the PI 3-kinase inhibitor) can affect neither cPLA(2) nor ERK phosphorylation. In A549 cells, PKC activator PMA cannot increase either the basal or thapsigargin-induced (3)H-AA release, while it can induce the phosphorylation of ERK and cPLA(2.) The PMA-induced ERK phosphorylation was inhibited by Ro 31-8220, LY 379196, rottlerin, and PD 98059, but unaffected by SB 203580 and wortmannin. Moreover, the phosphorylation by PMA was non-additive with that of thapsigargin. This implies that intracellular Ca(2+) level is the key factor for induction of cPLA(2) activity and thapsigargin-elicited ERK activation itself is substantially sufficient for cPLA(2) activation upon intracellular Ca(2+) increase.

Acetophenones↗
PubMed2000

Acrylamide-regulated neurofilament expression in rat pheochromocytoma cells.

Using the rat pheochromocytoma cell line (PC12), we present molecular evidence that the neurotoxicant acrylamide directly induces neurofilament gene expression, and the signaling pathways are initially distinctive from, but eventually merged into, that for nerve growth factor (NGF)-induced neurofilament expression. In PC12 cells, acrylamide increased neurofilament protein levels and synthesis. Acrylamide had no effect on the stability of neurofilament mRNAs suggesting that it directly increased neurofilament mRNA synthesis. K252a, a selective inhibitor for NGF receptor gp140trk, had no effect on acrylamide induction, but completely inhibited NGF-induced neurofilament protein synthesis. Therefore, the initial step for acrylamide signaling was distinctive from NGF. Dexamethasone reversed the effects of both NGF and acrylamide on neurofilament protein levels and synthesis indicated that there is a dexamethasone-sensitive signaling step upon which NGF and acrylamide merge, suggesting involvement of transcription-activating proteins like AP-1. These results, taken together with previous studies of transgenic mice that overexpress neurofilament genes, may partially explain the mechanisms of neurofilament accumulation in distal parts of large axons, a pathognomonic feature of acrylamide neurotoxicity in animals.

Acrylamide↗
PubMed2000

Cycloheximide-induced cPLA(2) activation is via the MKP-1 down-regulation and ERK activation.

Extracellular signal-regulated kinase (ERK)-dependent phosphorylation is an important regulator for cytosolic phospholipase A(2) (cPLA(2)). In this study, we found that the protein synthesis inhibitor cycloheximide can potentiate thapsigargin-induced arachidonic acid (AA) release concomitant with ERK phosphorylation from murine RAW 264.7 macrophages. The cycloheximide effect is not due to the activation of p38 mitogen-activated protein kinase (MAPK) nor c-Jun NH(2)-terminal kinase (JNK), because the activator of both MAPKs anisomycin does not elicit AA release. Cycloheximide effect is additive to the tyrosine phosphatase inhibitor orthovanadate since these two stimuli induced sustained ERK activation respectively through inhibition of the translation and activity of MAPK phosphatase-1 (MKP-1).

Animals↗
PubMed2000

Pyrimidinoceptor potentiation of macrophage PGE(2) release involved in the induction of nitric oxide synthase.

We have previously demonstrated that Ca(2+)/calmodulin-dependent protein kinase (CaMK) mediates pyrimidinoceptor potentiation of LPS-elicited inducible nitric oxide synthase (iNOS) induction in murine J774 macrophages. In the present paper, we have explored the role of cyclo-oxygenase (COX)-dependent prostaglandin E(2) (PGE(2)) formation in this event. In J774 macrophages predominantly expressing P2Y(6) receptors, the simultaneous addition of UTP and lipopolysaccharide (LPS) resulted in potentiated increase in PGE(2) release. UTP-induced increased PGE(2) release was demonstrated by a concomitant increase in COX-2 protein expression, and was decreased by inhibitors specific for phosphatidylinositide-phospholipase C (PI-PLC), CaMK, protein kinase C (PKC), nuclear factor-kappa B (NF-kappaB) or COX-2. NS-398 (a selective COX-2 inhibitor) reduced LPS plus UTP-elicited iNOS induction and nitrite accumulation, supporting for the positive regulation of iNOS gene expression by endogenous PGE(2). Moreover, the cyclic AMP/PKA-dependent up-regulation of iNOS expression mediated by PGE(2) was drawn from the inhibitory effects of 2',5'-dideoxyadenosine, KT5720 and H-89. Exogenous PGE(2) induced NF-kappaB activation and potentiated nitrite accumulation in response to LPS. In addition to COX-2 induction, arachidonic acid (AA) release and steady-state mRNA levels of type V secretory phospholipase A(2) (sPLA(2)) and Ca(2+)-independent PLA(2) (iPLA(2)) were also increased in the presence of LPS and UTP; the LPS-induced increase in iPLA(2) activity was also potentiated by UTP. Taken together, we conclude that UTP-mediated COX-2 and iPLA(2) potentiation and PGE(2) formation contribute to the iNOS induction, and that CaMK activation is the primary step in the UTP enhancement of COX-2 induction.

Animals↗
PubMed1999

Cold-induced ependymin expression in zebrafish and carp brain: implications for cold acclimation.

Cold acclimation has been suggested to be mediated by alternations in the gene expression pattern in the cold-adapted fish. To investigate the mechanism of cold acclimation in fish brain at the molecular level, relevant subsets of differentially expressed genes of interest were identified and cloned by the PCR-based subtraction suppression hybridization. Characterization of the selected cold-induced cDNA clones revealed one encoding ependymin. This gene was shown to be brain-specific. The expression of ependymin was induced by a temperature shift from 25 degrees C to 6 degrees C in Cyprinus carpio or 12 degrees C in Danio rerio. Activation of ependymin was detected 2 h after cold exposure and peaked at more than 10-fold at 12 h. This peak level remains unchanged until the temperature returns to 25 degrees C. Although the amount of soluble ependymin protein in brain was not changed by cold treatment, its level in the fibrous insoluble polymers increased 2-fold after exposure to low temperature. These findings indicate that the increase in ependymin expression is an early event that may play an important role in the cold acclimation of fish.

Acclimatization↗