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.

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 HepG₂ 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, HepG₂ and SMMC7721 cells in a dose-and time-dependent manner. Growth inhibitory activity and apoptosis were more sensitive in HepG₂ cells than in SMMC7721 cells, MKN45 and MKN28 cells. After 24 h incubation with sulindac at 2 mmol•L¯¹ and 4 mmol•L¯¹, the level of COX-2 and Bcl-2 protein were lowered in MKN45, SMMC7721 and HepG₂ 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.

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.

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.

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 min after reperfusion following a total of 60 min 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 (POD₃) and P OD₇ and of the serum alanine aminotransferase (ALT) on POD₃ 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 min 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.

[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.

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.

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.

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.

[Antisecretory effect of dl-(15R)-15 methyl-PGE2 methyl ester (PG6E) on perfusing rats in vivo]

The antisecretion effect of dl-(15R)-15 methyl-PGE2 methyl ester (PG6E) was studied in perfusing rats in vivo. The results showed that PG6E at the dose 0.1 mg.kg-1 decreased markedly the acid secretion and antagonized the gastric acid secretion induced by histamine, pilocarpin and pentagastrin in rats. This action of PG6E appeared to be similar to that of cimetidine (40 mg.kg-1).

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.

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.

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.

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.

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.

Oxidative stress before and after operation in patients with chronic cholecystitis containing gallstone

To study the relationship of oxidative, antioxidative constituents and antioxidases in blood with chronic cholecystitis containing gallstone, levels of lipoperoxides (LPO), nitric oxide (NO), vitamin C(VC), vitamin E (VE) and beta-carotene (beta-CAR) in plasma as well as level of LPO, activities of superoxide dismulase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in erythrocytes were investigated by spectrophotometric assay in 107 patients with this condition (PCg) and 100 healthy volunteers (HVs). Compared with HVs group, the average value of LPO and NO in plasma and that of LPO in erythrocytes of PCg group were significantly increased (P < 0.0001), while that of VC, VE and beta-CAR in plasma and the average activities of SOD, CAT and GSH-Px in erythrocytes were significantly decreased (P < 0.0001). Linear regression and correlation analysis for 107 preoperative PCg showed that the value of LPO and NO in plasma and that of LPO in erythrocytes of PCg gradually increased (P < 0.0001), representing a significant linear positive correlation. The value of VC, VE and beta-CAR in plasma and that of SOD, CAT and GSH-Px in erythrocytes of PCg gradually decreased (P < 0.0001), representing a significant linear negative correlation. Stepwise regression and correlation analysis for 107 preoperative PCg suggested that the closest correlation was observed between the course of disease and the value of NO and VC in plasma and that of SOD, GSH-Px and LPO in erythrocytes, r = 0.7306, F = 32.1408, P < 0.0001. Compared with the preoperative PCg group, the average value of LPO and NO in plasma and that of LPO in erythrocytes of the postoperative PCg group were significantly decreased (P < 0.0001). Furthermore, the average value of VC in plasma and that of SOD, CAT and GSH-Px in erythrocytes of the postoperative PCg group were significantly increased (P < 0.0001), whereas no significant difference was found between their average value of VE and beta-CAR in plasma. These findings suggested that oxidative stress was an aggravating pathological condition in PCg group. Therefore, we recommend that in treating PCg, antioxidants such as VC, VE, beta-CAR should be given in order to alleviate their potential oxidative damages.

Upregulation of lipocortin 1 inhibits tumour necrosis factor-induced apoptosis in human leukaemic cells: a possible mechanism of resistance to immune surveillance

The signal transduction pathway through which tumour necrosis factor (TNF) induces apoptosis in leukaemic cells may involve activation of cytosolic phospholipase A(2) (cPLA(2)). The steroids dexamethasone (Dex) and 1,25(OH)(2) D(3) both render U937 leukaemic cells resistant to TNF-induced apoptosis. In this study, we found that Dex inhibited both spontaneous and TNF-induced activation of cPLA(2). Dex had no direct effect on cellular cPLA(2) levels, but facilitated cPLA(2) degradation upon subsequent stimulation of cells with TNF. In addition, Dex increased synthesis of the endogenous cPLA(2) inhibitor lipocortin 1 (LC1). An antisense oligonucleotide to LC1 could completely abrogate Dex-induced resistance to the cytotoxic action of TNF. Constitutive LC1 levels were relatively higher in myeloid leukaemic blasts showing resistance to TNF than TNF-sensitive myeloid leukaemic cell lines. Our data suggest that Dex confers the resistance of U937 cells to TNF-induced apoptosis by upregulating intracellular levels of LC1 and by facilitating a negative-feedback loop, which is activated upon stimulation with TNF. High constitutive levels of LC1 in leukaemic blasts may protect them against immune-mediated killing.

Glutathione loading prevents free radical injury in red blood cells after storage

We have previously demonstrated that the loss of glutathione (GSH) and GSH-peroxidase (GSH-PX) in banked red blood cells (RBCs) is accompanied by oxidative modifications of lipids, proteins and loss of membrane integrity. The objective of this study was to determine whether artificial increases in antioxidant (GSH) or antioxidant enzyme (catalase) content could protect membrane damage in the banked RBCs following an oxidant challenge. RBCs stored at 1-6 degrees C for 0, 42 and 84 days in a conventional additive solution (Adsol) were subjected to oxidative stress using ferric/ascorbic acid (Fe/ASC) before and after enriching them with GSH or catalase using a hypotonic lysis-isoosmotic resealing procedure. This lysis-resealing procedure in the presence of GSH/catalase raised intracellular GSH and catalase concentrations 4-6 fold, yet produced only a small reduction in mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentrations (MCHC). Indicators of oxidative stress and membrane integrity were measured, including acetylcholinesterase (AChE) activity, GSH concentration, phosphatidylserine (PS) externalization (prothrombin-converting activity) and transmembrane lipid movements (14C-lyso phosphatidylcholine flip-flop and PS transport). GSH-enrichment protected AChE activity in fresh (0 day) and stored (42 and 84 days) RBCs from Fe/ASC oxidation by 10, 23 and 26%, respectively, compared with not-enriched controls. Following oxidative stress, the rate of transbilayer lipid flip-flop did not increase in fresh cells, but increased 9.3% in 42-day stored cells. Phosphatidylserine exposure, as measured by prothrombinase activity, increased 2.4-fold in fresh and 5.2-fold in 42-day stored cells exposed to Fe/ASC. Previous studies have shown that 42-day storage causes a moderate decrease in PS transport (approximately 50%), whereas transport rates declined by up to 75% in stored RBCs when challenged with Fe/ASC. GSH-enrichment prevented the increase in passive lipid flip-flop and the increase in prothrombinase activity, but offered no protection against oxidative damage of PS transport. In contrast to these effects, catalase-enrichment failed to protect GSH levels and AChE activity upon oxidative stress. Membrane protein thiol oxidation was assessed by labeling reactive protein thiols with 5-acetalamidofluorescein followed by immunoblotting with antifluorescein antibodies. Significant oxidation of membrane proteins was confirmed by a greater loss of thiols in stored RBCs than in fresh RBCs. These results demonstrate that it may be possible to prevent storage-mediated loss of AChE, increased lipid flip-flop, and increased PS exposure, by maintaining or increasing GSH levels of banked RBCs.

[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.

Nuclear localization of the human mutY homologue hMYH

The cDNA of the human mutY homologue (hMYH) was cloned from the total RNA of the tumor cell line SU-DHL-1 by reverse transcription-polymerase chain reaction (RT-PCR). Expression of hMYH in a plasmid can partially revert the mutator phenotype of the Escherichia coli mutY mutant MK609(DE3). The majority of the recombinant hMYH protein in E. coli was precipitated in the inclusion bodies. A minor fraction of the soluble recombinant protein was concentrated as the source of the protein in the activity assay. Recombinant hMYH displayed both glycosylase and AP lyase activity. Three independent rabbit antisera against an N-terminal peptide, HY90, a recombinant C-terminal fragment, and the full-length hMYH recombinant protein were prepared and affinity-purified, and these antisera recognized the 59 kDa endogenous hMYH protein in HeLa cells. Immunofluorescent staining experiments with these three antisera showed a consistent nuclear distribution of hMYH, excluding the nucleoli. This nuclear staining pattern was abolished if the antisera were incubated with specific peptide/protein competitors, whereas the staining pattern was unaffected if the antisera were incubated with nonspecific peptide competitors. Consistent with the immunofluorescent staining results, a flag-tagged transfected hMYH also showed a nuclear staining pattern excluding the nucleoli. These results suggest that hMYH is indeed a functional homologue of E. coli MutY and is localized in the nuclei of mammalian cells.

Identification of alternative splicing variants of the beta subunit of human Ca(2+)/calmodulin-dependent protein kinase II with different activities

The beta subunit of human Ca(2+)/calmodulin-dependent protein kinase II (beta CaMKII) was identified by searching through an expressed sequence tag database and rapid amplification of cDNA 5'-ends and was assigned to chromosome 7. Reverse transcription-polymerase chain reaction and sequencing analysis identified at least five alternative splicing variants of beta CaMKII (beta, beta6, betae, beta'e, and beta7) in brain and two of them (beta6 and beta7) were first detected in any species. When expressed in HEK 293 cells, the Ca(2+)/calmodulin-dependent kinase activity of beta7, the shortest variant, was much lower than that of either beta (the longest one) or betae (the medium one), suggesting possible regulation of beta CaMKII activity by alternative splicing.

Polyether mimics of naturally occurring cytotoxic annonaceous acetogenins

On the basis of the ionophore model, polyether analogues 4 and 6 were designed and synthesized to mimic the naturally occurring annonaceous acetogenins corossolin (2) and bullatin (5), which were discovered as members of a large family of novel polyketides with cytotoxicity, antitumoral, and other biological activities since 1982. The preliminary screening shows that they have compatible cytotoxicity with the corresponding natural annonaceous acetogenins. These results open a potential way to find more active antitumor agents with simplified structures based on natural annonaceous acetogenins.

Effects of acute and chronic administration of MCI-225, a new selective noradrenaline reuptake inhibitor with 5-HT3 receptor blocking action, on extracellular noradrenaline levels in the hypothalamus of stressed rats

In the present study, we investigated the effects of acute and chronic systemic administration of MCI-225 (4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-d]pyrimidine monohydrate hydrochloride), a newly-developed selective noradrenaline (NA) reuptake inhibitor with 5-HT3-receptor-blocking action, on extracellular NA levels in the hypothalamus of stressed and non-stressed rats by utilizing intracerebral microdialysis. Acute administration of MCI-225 (3 and 10 mg/kg, p.o.) significantly and dose-dependently increased extracellular NA levels in the hypothalamus in non-stressed rats. Footshock for 20 min also significantly increased NA levels in the hypothalamus of both groups of rats pretreated with vehicle and MCI-225. Although chronic administration of MCI-225 (3 or 10 mg/kg, p.o. for 14 days) did not alter the basal extracellular NA levels in the hypothalamus, the stress-induced increases in extracellular NA levels were significantly lower in rats chronically treated with MCI-225 (10 mg/kg) than those of rats pretreated with vehicle for the same period. The increase in extracellular NA levels induced by MCI-225 challenge (3 or 10 mg/kg, p.o.) were not different between rats chronically treated with MCI-225 or vehicle. These results suggest that MCI-225 enhances extracellular NA levels in the hypothalamus in both non-stressed and stressed rats by inhibiting NA uptake and that chronic systemic administration of MCI-225 did not alter basal extracellular NA levels, but reduced the increase in NA release caused by footshock stress. These data suggest the possibility that MCI-225 might possess anxiolytic and/or antidepressant properties.

The first total synthesis of annonacin, the most typical monotetrahydrofuran annonaceous acetogenins

The first total synthesis of annonacin (1) was achieved by a highly convergent synthetic strategy. All the stereogenic centers were derived from three natural hydroxy acids respectively, except that those at C19 and C20 were produced from a Sharpless AD reaction.

Base-catalyzed epimerization of the butenolide in annonaceous acetogenins

The elusive epimerization process in the chiral butenolide moiety of Annonaceous acetogenins was examined under several sets of conditions commonly used for elimination leading to the alpha, beta-unsaturated lactone and the results provide practical guidance in choosing elimination conditions.