Toxic effects of aminophenols on aquatic life using the zebrafish embryo test and the comet assay.
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Aminophenols↗
Biomedical subjects
Y L Wu
Publications and source records attributed to Y L Wu.
Regulation of progesterone and prostaglandin F2alpha production in the CL.
After the luteinizing hormone (LH) surge, the cells that remain from the ovulated follicle undergo a process of differentiation termed luteinization. Two key features of the cells after luteinization are the capacity for tremendous production of progesterone [10(16) molecules of progesterone per (min/(g of CL))] and the capacity to undergo regression or death of the cells at the appropriate time. There are two steroidogenic cell types, the small and large luteal cells that are regulated by different mechanisms. In small luteal cells, production of progesterone is stimulated by LH through the protein kinase A (PKA) pathway. The large luteal cells of ruminants produce large quantities of progesterone that is independent of LH stimulation. Although luteotrophins clearly regulate luteal function, much of luteal progesterone production in some species appears to be constitutive, consistent with the autonomous aspects of the large luteal cell. The key regulated step in luteal progesterone production appears to be regulation of transport of cholesterol to the inner mitochondrial membrane apparently mediated by the steroidogenic acute regulatory protein (StAR). In addition, our recent research indicates that PKA is tonically active in large luteal cells and this may be responsible for the high, relatively autonomous nature of luteal progesterone production. Regression of the corpus luteum (CL) in many species is initiated by prostaglandin (PG) F2alpha secreted from the uterus. Luteal cells also have the capacity for production of PGF2alpha. Luteal PGF2alpha production can be regulated by a variety of substances including inhibition by progesterone and stimulation by cytokines. We have also characterized a positive feedback pathway in ruminant and porcine CL in which small amounts of uterine PGF(2alpha) stimulate intraluteal production of PGF2alpha due to induction of the cycloxygenase-2 (Cox-2) enzyme in large luteal cells. This positive feedback pathway is only present in CL that has acquired the capacity for luteal regression ( approximately day 7 in cow, approximately day 13 in pig). Regulation by protein kinase C (PKC) of transcriptional factors interacting with an E-box in the 5' flanking region of the Cox-2 gene is the critical regulatory element involved in this positive feedback pathway. Thus, luteinization in some species appears to change specific gene transcription such that progesterone production becomes relatively independent of acute luteotrophic regulation and intraluteal PGF2alpha synthesis is induced by the second messenger pathways that are activated by PGF2alpha.
Animals↗
Aquapuncture therapy of repeat breeding in dairy cattle.
Repeat breeders cause great economic loss in dairy herds. This study determined the efficacy of simple aquapuncture therapy (acupuncture combined with injection) to treat repeat breeders in two dairy herds (one in Hsinchu County and the other in Tainan County). Both herds had used gonadotropin-releasing hormone (GnRH) beforehand to treat the symptom but the success rate was poor--about 30%. Therefore, cows that failed to respond to GnRH were given the aquapuncture treatment. A total of 18 animals (two heifers and 16 cows) that had failed to conceive to 3-9 services were treated by aquapuncture, in which 10 ml and 5 ml of 50% glucose solution were injected at Baihui (Hundred Meetings, the depression in the center of the lumbosacral space) and Shenpeng (Kidney Shelf, the depression in the space between the lumbar vertebral transverse processes 5-6) acupoints, respectively with a 21G, 1.5-inch hypodermic needle. Both acupoints belong to the traditional acupuncture points of bovine and equine systems. Most animals showed heat within 14 days after aquapuncture and were inseminated artificially. Serum progesterone concentrations and rectal palpation were used for pregnancy diagnosis. The pregnancy rate after the treatment was 14/18 (77.7%) and 12/18 (66.6%) based on progesterone concentration and rectal palpation respectively, suggesting acupuncture as a simple and effective method to treat repeat breeders in dairy herds. However, the final result obtained from actual delivery of fetus in the experimental animals was only 8/18 (44.4%).
Acupuncture Points↗
Heterozygosity for the neurofibromatosis 1 (NF1) tumor suppressor results in abnormalities in cell attachment, spreading and motility in astrocytes.
Individuals with the neurofibromatosis 1 (NF1) tumor predisposition syndrome develop low-grade pilocytic astrocytomas at an increased frequency. Previously, we demonstrated that astrocytes from mice heterozygous for a targeted mutation in the Nf1 gene (Nf1+/- astrocytes) exhibit a cell autonomous growth advantage associated with increased RAS pathway activation. In this report, we extend our initial characterization of the effect of reduced Nf1 gene expression on astrocyte function by demonstrating that Nf1+/- astrocytes exhibit decreased cell attachment, actin cytoskeletal abnormalities during the initial phases of cell spreading, and increased cell motility. Whereas these cytoskeletal abnormalities were also observed in Nf1-/- astrocytes, astrocytes expressing a constitutively active RAS molecule showed increased cell motility and abnormal actin cytoskeleton organization during cell spreading, but exhibited normal cell attachment. Based on ongoing gene expression profiling experiments on human astrocytoma tumors, we demonstrate increased expression of two proteins implicated in cell attachment, spreading and motility (GAP43 and T-cadherin) in Nf1+/- and Nf1-/- astrocytes. These results support the emerging notion that tumor suppressor gene heterozygosity results in abnormalities in cell function that may contribute to the pathogenesis of non-tumor phenotypes in NF1.
Animals↗
Construction of single-chain interleukin-12 DNA plasmid to treat airway hyperresponsiveness in an animal model of asthma.
Allergic asthma is strongly associated with the airway inflammation caused by the dysregulated production of cytokines secreted by the allergen-specific type-2 T helper (Th2) cells. Interleukin (IL)-12 is a heterodimeric cytokine, which strongly promotes the differentiation of naive CD4(+) T cells to the type-1 T helper (Th1) phenotype and suppresses the expression of Th2 cytokines. Therefore, immunotherapy with IL-12 has been suggested as a possible therapy for asthma. In previous studies, we developed a murine model of airway inflammation based on the purified, house dust-mite allergen Der p 1 (Dermatophagodies pteronyssinus) as a clinically relevant allergen. We hypothesized that the expression of IL-12 in the airway may represent an effective therapy for allergic airway diseases. In this study, we investigate whether the local transfer of the IL-12 gene to respiratory tissues modifies allergic inflammation and airway hyper-responsiveness (AHR) in our disease model. To enhance the in vivo delivery of the IL-12 gene, we expressed the murine single-chain IL-12 protein from a nonviral vector to which the two IL-12 subunits (p35 and p40) were linked by a 14- to 18-amino-acid linker. One of these single-chain IL-12s, containing an 18 amino-acid polypeptide linker, was stably expressed and had a high level of biological activity comparable to that of native IL-12 in vitro. In mice with Der p 1-induced asthma, the local administration of this IL-12 fusion gene into the lungs significantly prevented the development of AHR, abrogated airway eosinophilia, and inhibited type-2 cytokine production. These findings indicate that the local transfer of the single-chain IL-12 gene is effective in modulating pulmonary allergic responses and may be a convenient method for future applications of DNA vaccination.
Allergens↗
Localization of A-type K+ channel subunit Kv4.2 in rat brain.
Kv4.2, a voltage-gated K+ (Kv) channel subunit, has been suggested to be the key component of the subthreshold A-type K+ currents (I(SA)s) recorded from the specific subcellular compartments of certain CNS neurons. To correlate Kv4.2 localization with the I(SA)s detected, immunohistochemistry will be useful. Although the Kv4.2 immunostaining pattern in the hippocampus and cerebellum has been reported, the Kv4.2 antibody used was not specific. Furthermore, Kv4.2 localization in other brain regions remains unclear. In this report, we first demonstrated the specificity of a new Kv4.2 antibody, and then used it to examine Kv4.2 localization throughout adult rat brain by immunohistochemistry. At the cellular level, Kv4.2 was found in neurons but not glias. At the subcellular level, Kv4.2 was localized in the somatodendritic compartment of most neurons examined. Nevertheless, our preliminary data indicated that Kv4.2 might be also present in the axon/terminal compartment. At the functional level, our data indicates that Kv4.2 localization and I(SA) correlate quite well in some CNS neurons, supporting that Kv4.2 is the key component of some I(SA)s recorded in vivo.
Animals↗
Studies toward the total synthesis of clavulactone.
Synthetic studies directed toward a total synthesis of clavulactone are reported. In light of the analysis made in our previous work, cyclopentane 4a (a key intermediate in the present work) was synthesized through a radical-mediated ring closure of a rationally designed substrate 25. Using HWE reactions, the lower and upper side-chains of 4a were converted into an allyl chloride and an allyl cyanohydrin, respectively. Subsequent treatment of the allyl chloride/cyanohydrin in a highly diluted THF solution with sodium bis(trimethylsiliyl)amide led to intramolecular alkylation and thus completed a major endeavor in synthesizing the dolabellane framework, construction of the eleven-membered ring. SmI(2)-mediated lactonization as a model reaction for the formation of the alpha,beta-unsaturated delta-lactone segment of clavulactone is also described.
Animals↗
Enantioselective syntheses of monotetrahydrofuran Annonaceous acetogenins tonkinecin and annonacin starting from carbohydrates.
The total synthesis of two mono-THF acetogenins, tonkinecin (1) and annonacin (2), is reported in full detail. Terminal acetylene 3 prepared from D-glucono-delta-lactone and asymmetric dihydroxylation was employed as a common intermediate for both targets 1 and 2. Pd(0)-catalyzed coupling reaction of 3 with vinyl iodides 4 and 5, the chiral centers of which were taken from D-xylose and S-(-)-ethyl lactate, afforded enyne 26 and 27, respectively. Selective hydrogenation of 26 or 27 with diimide followed by removal of MOM ethers completed the synthesis of 1. A coupling reaction between the lithium derivative of 3 and epoxide 6 in the presence of boron trifluoride etherate gave 42. Both chiral centers in epoxide 6 were taken from L-ascorbic acid. Subsequent catalytic hydrogenation and MOM protection led to 43b. Introduction of the butenolide moiety by aldol condensation of protected S-lactal followed by cleavage of all MOM ethers completed the synthesis of 2.
Carbohydrates↗
Differential regulation of prostaglandin endoperoxide synthase-2 transcription in ovine granulosa and large luteal cells.
The objective of the present study was to evaluate second messenger regulation of prostaglandin synthase-2 (PGS-2) mRNA and PGS-2 promoter in ovine granulosa cells and large luteal cells. In granulosa cells, PGS-2 mRNA was induced by forskolin (PKA activator) but not by phorbol didecanoate (PDD; PKC activator) with maximal stimulation at 24 h. In contrast, PDD was the more potent inducer in large luteal cells with the most dramatic effect by 4 h. Similarly, forskolin but not PDD increased media PGF2 alpha in granulosa cells at 24 h; whereas, PDD but not forskolin increased PGF2 alpha at 4 h and 24 h in large luteal cells. To evaluate if these effects were due to activation of transcription, a plasmid was constructed containing 1500 bp of PGS-2 promoter linked to a luciferase gene. Forskolin stimulated transcription from this construct in granulosa cells (5-fold); whereas, PDD but not forskolin stimulated transcription in large luteal cells (40-fold). Taking these findings together, we propose that transcriptional regulation of the PGS-2 gene changes from PKA-dependence in granulosa cells to PKC-dependence in large luteal cells after luteinization.
Animals↗
Atemoyacin E, a bis-tetrahydrofuran annonaceous acetogenin from Annona atemoya seeds.
Atemoyacin E (I), a new adjacent bis-tetrahydrofuran annonaceous acetogenin was isolated and characterized from the seeds of Annona atemoya.
Annonaceae↗
Prostaglandin F(2alpha) receptor in the corpus luteum: recent information on the gene, messenger ribonucleic acid, and protein.
The prostaglandin (PG) F(2alpha) receptor (FPr) in the corpus luteum is essential for maintaining normal reproductive cyclicity in many species. Activation of this seven-transmembrane spanning receptor at the end of the cycle leads to a decrease in progesterone and the demise of the corpus luteum (luteolysis). Recently, the gene structure of the FPr in three mammalian species has been elucidated; however, promoter regulation of the gene is still poorly understood. The FPr mRNA is extremely low in steroidogenic follicular cells (theca or granulosa) but is expressed at high levels in the corpus luteum, particularly in the large luteal cells. Treatment with PGF(2alpha) decreased FPr mRNA expression in luteal cells in most species that have been studied. Key amino acids have been suggested to be critical for binding of FPr to PGF(2alpha) based on three-dimensional modeling and comparisons with other G-protein-coupled receptors. Moieties of the PGF(2alpha) molecule that are essential for binding or specificity of binding to the FPr have been identified by radioreceptor binding studies. In this article, recent information is reviewed on the structure of the FPr gene, regulation of luteal FPr mRNA, and receptor/ligand interaction requirements for the FPr protein.
Amino Acid Sequence↗
Transcriptional regulation of cyclooxygenase-2 gene in ovine large luteal cells.
There is positive feedback pathway in the ovine large luteal cell, such that prostaglandin (PG) F(2 alpha) stimulation induces intraluteal PGF(2 alpha) production as the result of induction of one of the rate-limiting enzymes in PG production, cyclooxygenase-2 (Cox-2). The objective of the present study was to evaluate the intracellular effector systems and important DNA transcriptional element(s) involved in regulating the Cox-2 gene in ovine large luteal cells. In transient transfection assays, Cox-2 promoter was rapidly induced (4 h) by phorbol didecanoate (a protein kinase [PK] C activator), ionomycin, and cloprostenol (PGF(2 alpha) analogue), with a peak induction at 12 h. Cloprostenol-mediated promoter activation was not blocked by inhibition of various second messenger systems, including PKA, calcium calmodulin kinase II, or mitogen-activated protein kinases. However, myristoylated PKC pseudosubstrate peptide inhibited cloprostenol stimulation of Cox-2 promoter, indicating the critical role of PKC in this stimulation. The Cox-2 promoter could be reduced to 282 base pairs (bp) of the 5' flanking sequence with retention of full inducibility by cloprostenol. Mutation of three critical cis-responsive elements within this 282-bp region (C/EBP, cAMP responsive element [CRE], and E-box) indicated that E-box was critical in both basal and cloprostenol-induced promoter activity. However, there was also significant but less dramatic inhibition of cloprostenol stimulation by mutation of C/EBP and CRE in the Cox-2 promoter, and mutation of all three elements eliminated cloprostenol induction of this promoter. Electrophoretic mobility shift assays of nuclear extracts from large luteal cells revealed that upstream stimulatory factor (USF)-1 and USF-2 bound to the E-box in Cox-2. Thus, PKC directly regulates transcription of the Cox-2 gene in large luteal cells by acting through DNA elements close to the putative transcriptional start point, particularly an E-box region at -50 bp.
Animals↗
Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats.
AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion. METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15(IO-15), 20(IO-20) and 30(IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed. RESULTS: At 60 minutes after reperfusion following a total of 60 minutes of hepatic inflow occlusion, EC values in IO-10 (0.749 +/- 0.012) and IO-15 (0.699 +/- 0.002) groups were rapidly restored to that in SO group (0.748 +/- 0.016), TTC reduction activities remained in high levels (0.144 +/- 0.002 mg/mg protein, 0.139 +/- 0.003 mg/mg protein and 0.121 +/- 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 +/- 0.023 and 0.534 +/- 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 +/- 0.005 mg/mg protein and 0.061 +/- 0.003 mg/mg protein). No recovery in EC values (0.228 +/- 0.004) and a progressive decrease in TTC reduction activities (0.033 +/- 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD(3)) and POD(7) and of the serum alanine aminotransferase (ALT) on POD(3) in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group. CONCLUSION: Hepatic inflow occlusion during 60 minutes for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.
Alanine Transaminase↗
Growth inhibition and apoptosis induction of Sulindac on Human gastric cancer cells.
AIM: To evaluate the effects of sulindac in inducing growth inhibition and apoptosis of human gastric cancer cells in comparison with human hepatocellular carcinoma (HCC) cells. METHODS: The human gastric cancer cell lines MKN45 and MKN28 and human hepatocellular carcinoma cell lines HepG(2) and SMMC7721 were used for the study. Anti-proliferative effect was measured by MTT assay, and apoptosis was determined by Hoechst-33258 staining, electronography and DNA fragmentation. The protein of cyclooxygenase-2 (COX-2) and Bcl-2 were detected by Western dot blotting. RESULTS: Sulindac could initiate growth inhibition and apoptosis of MKN45, MKN28, HepG(2) and SMMC7721 cells in a dose-and time-dependent manner. Growth inhibitory activity and apoptosis were more sensitive in HepG(2) cells than in SMMC7721 cells, MKN45 and MKN28 cells. After 24 hours incubation with sulindac at 2mmol x L(-1) and 4mmol x L(-1), the level of COX-2 and Bcl-2 protein were lowered in MKN45, SMMC7721 and HepG(2) cells but not in MKN28 cells. CONCLUSION: Sulindac could inhibit the growth of gastric cancer cells and HCC cells effectively in vitro by apoptosis induction, which was associated with regression of COX-2 and Bcl-2 expression. The growth inhibition and apoptosis of HCC cells were greater than that of human gastric cancer cells. The different effects of apoptosis in gastric cancer cells may be related to the differentiation of the cells.
Anti-Inflammatory Agents, Non-Steroidal↗
Foix-Chavany-Marie syndrome.
Anarthria and bilateral central faciolinguopharyngeomasticatory paralysis with automatic voluntary dissociation are the clinical hallmarks of Foix-Chavany-Marie syndrome (FCMS), the cortico-subcortial type of suprabulbar palsy. We present a 64-year-old man who was admitted due to acute onset of speechlessness for days. Neurological examinations demonstrated typical features of FCMS. Cranial MRI showed a right opercular lesion and several lacunar infarcts in bilateral hemispheres. Hexamethylpropylenamine oxime (HMPAO) brain SPECT revealed hypoperfusion in bilateral opercular regions and notably on the right side. In review of previous reports, the most common etiology of FCMS is stroke in the region of either operculum. Our case may be a good example of FCMS after multiple cerebrovascular insults over bilateral opercular cortico-subcortical areas as demonstrated in MRI and SPECT studies.
Diagnosis, Differential↗
[Determination of ciprofloxacin in urine using terbium ion as fluorescent probe].
Factors effecting the fluorescence characteristics of the reaction CPFX-Tb were studied thoroughly. The effect of the experimental conditions on the fluorescence intensity was defined. In the pH 6.0 media, CPFX-Tb complex fluorescence system can emit intrinsic fluorescence of Tb. The excitation and emission wavelengths are 328 nm and 545 nm. The linear range is 1.0 x 10(-8)-1.0 x 10(-6) mol.L-1. The regression equation is F = 1.57 + 4.87 x 10(8) c, r = 0.9999 with the detection limit of 5.0 x 10(-9) mol.L-1. It has been satisfactory for the determination of trace ciprofloxacin in urine by using terbium ion as fluorescent probe.
Anti-Infective Agents↗
General and efficient syntheses of C(18)-4,8-sphingadienines via S(N)2'-type homoallylic coupling reactions mediated by thioether-stabilized copper reagents.
The stereoselective syntheses of C(18)-4,8-sphingadienines 3 and 4 as analogues of sphingosine 1 are described. The key step in these syntheses involved a novel S(N)2'-type homoallylic coupling reaction between the corresponding thioether-stabilized allylic copper reagents and the allylic mesylate 7. The thioether-stabilized allylic copper reagents were easily prepared and retained the configuration of their double bond during the coupling reactions, thus overcoming the problem of isomerization which was normally associated with the use of allylic organometallic reagents in such applications.
Allyl Compounds↗
[The expression and significance of VEGF mRNA and bFGF mRNA in the malignant neoplasms of ovary].
The expression and significance of VEGF mRNA and bFGF mRNA in the malignant neoplasms of ovary were studied by in situ hybridization technique. The results were that the positive rates of VEGF mRNA and bFGF mRNA were higher in the serous adenocarcinoma and embryonal carcinoma than that in the mucous adenocarcinoma and granulosa cell tumor. The positive rates of VEGF mRNA and bFGF mRNA were lower in the cases of clinical Stage I and without metastasis than that of clinical Stage III-IV and with metastasis. The results suggest that the expressions of VEGF mRNA and bFGF mRNA might be related to the pathological types, clinical stages, and metastasis of the malignant neoplasms of ovary and the patients who have positive expression of VEGF mRNA and bFGF mRNA might have a poor prognosis.
Adolescent↗