Antisense IRAK-2 oligodeoxynucleotide inhibits interleukin-1-induced nuclear factor-kappa B activation in vitro

AIM

To study the inhibitory effects of antisense interleukin-1 receptor associated kinase-2 (IRAK-2) oligodeoxynucleotide (ODN) on interleukin-1 (IL-1)-stimulated nuclear factor-kappa B (NF-kappa B) activation.

METHODS

Antisense IRAK-2 ODN was delivered by lipofectin encapsulation into human embryonic kidney 293 cells (HEK 293 cells). The levels of NF-kappa B were assayed by sandwich ELISA.

RESULTS

(1) Treatment of HEK 293 cells with IL-1 enhanced NF-kappa B level in nuclei by 518.5% +/- 2.1%. (2) Antisense IRAK-2 ODN inhibited IL-1-induced NF-kappa B activation in a concentration (1-8 micrograms)- and time (5-24 h)-dependent manner. A maximum inhibition was 70.7% +/- 1.0% from Acontrol 0.834 +/- 0.014 to 0.244 +/- 0.008 after treatment with antisense IRAK-2 ODN 4 micrograms for 8 h.

CONCLUSION

Antisense IRAK-2 ODN inhibited IL-1-induced NF-kappa B activation.

Effect of anoxic preconditioning on ATP-sensitive potassium channels in guinea-pig ventricular myocytes

Ischemic or hypoxic preconditioning in experimental animals and humans is described. The mechanism of preconditioning may involve several endogenous substances released from ischemic or hypoxic tissues (such as adenosine, noradrenaline and bradykinin) that stimulate protein kinase C (PKC), which then phosphorylates ATP-sensitive potassium channels (K(ATP) channels). However, the effect of hypoxic preconditioning on K(ATP) channels in guinea-pig ventricular myocytes is unclear. The uncoupler carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) has been shown to activate K(ATP) channels in isolated cardiac cells. In the present study we tested whether anoxic preconditioning (APC) could affect the opening of K(ATP) channels activated by metabolic inhibition (MI) induced by FCCP in cell-attached and inside-out patches from guinea-pig ventricular myocytes. We measured the channel activity as NP(o)i and calculated it using the formula Po=I/(Ni), where Po is open-state probability, I is the mean patch current carried by all K(ATP) channels activated in a particular patch for a certain period of time, N is the number of functioning channels in the patch, and i is the unitary current of the K(ATP) channels. In cell-attached membrane patches, after about 5 min of initiating MI, K(ATP) channels were activated at a holding potential of +40 mV (NP(o)i=3.70+/-0.9 pA); APC pretreatment (3 min of anoxia followed by 7 min of reoxygenation) before MI (APC+MI group) shortened the time to activate K(ATP) channels by MI (2.3+/-0.5 min) and increased the activity of K(ATP)currents (NP(o)i=8.4+/-0.5 pA). This effect of APC was eliminated by administration of a PKC blocker, chelerythrine (5 microM), for 5 min before the APC pretreatment. In the inside-out patches, the IC50 of intracellular ATP against the K(ATP) channels in the APC+MI group was significantly increased to 642 microM compared to that in the MI group (IC50 of intracellular ATP =252 microM). Chelerythrine inhibited the effect of APC on the sensitivity of K(ATP) channels to the intracellular ATP concentration (IC50 of [ATP]i=301 microM). Our results demonstrate that APC can increase and accelerate the opening of K(ATP) channels induced by MI, and decrease the sensitivity of K(ATP) channels to [ATP]i, which is mediated by promoting the activation of PKC induced by APC.

Studying the growth of cervical carcinoma nests and angiogenesis by immunostaining, quantitation and three-dimensional structural analysis

OBJECTIVE

To analyze the relationship and mutual effect of the growth of cervical carcinoma nests and angiogenesis.

STUDY DESIGN

Serial paraffin sections of cervical squamous carcinoma were stained in repeated order with hematoxylin-eosin (HE), immunostain for factor VIII-related antigen, type IV collagen and proliferating cell nuclear antigen (PCNA). Three-dimensional reconstructions were made, and the volumes of carcinoma nests, necrosis and microvessels were measured.

RESULTS

Two types of cervical carcinoma nests were distinguished on the basis of their growth characteristics and vascularity (groups I and II). Group I nests: The carcinoma cells were proliferating actively, as determined by their morphology and PCNA staining. There were abundant microvessels. Some endothelial sprouts and cords penetrated the nests and then formed networks and new vessels. The volume ratio of microvessels, including sprouts and cords, to the nests was 0.6282:1. Group II nests: The center of these nests underwent necrosis. The peripheral cells were rather small, with no mitosis. The PCNA index was rather low; these nests grew very slowly. There were only a few surrounding microvessels with no endothelial sprouts or cords. The volume ratio of vessels to nest was 0.0657:1.

CONCLUSION

Two types of cervical carcinoma nests show a close relationship and mutual effect of the growth of carcinoma nest and angiogenesis. Group I nests grow and develop well, with abundant microvessels. Thus, many tumor cells may be angiogenic and induce angiogenesis; growth of the nests seemed dependent on adequate neovascularization. Group II nests grow slowly, with a few microvessels; the center of the nests undergoes necrosis. The inadequate blood supply must be one of the important causes of necrosis. Considering that there must have been abundant neovascularization during their growth in the past, most of the microvessels must have been obliterated and then reabsorbed to make the remaining vessels so few.

GSTT1 and GSTM1 null genotypes and the risk of gastric cancer: a case-control study in a Chinese population

Glutathione S-transferase (GST) enzymes are involved in detoxification of many potentially carcinogenic compounds. The homozygous deletions or null genotypes of GSTT1 (theta class) and GSTM1 (mu class) genes may be associated with an increased risk of cancer. Few studies have evaluated the relationship between GSTT1, GSTM1 and the risk of gastric cancer, as well as the potential interactions between these genetic markers and other risk factors of gastric cancer in the Chinese population. We conducted a case-control study with 143 cases with gastric cancer, 166 chronic gastritis (CG) cases and 433 cancer-free population controls from Yangzhong County, China. The epidemiological data were collected by a standard questionnaire for all of the subjects, and blood samples were obtained from 91 gastric cancer cases, 146 CG cases, and 429 controls. GSTT1 and GSTM1 genotypes were assayed by the PCR method, and Helicobacter pylori infection was measured by the ELISA method. Using logistic regression model in SAS, we assessed the independent effects of GSTT1 and GSTM1 null genotypes on the risk of gastric cancer and their potential interactions with other factors. The prevalence of GSTM1 null genotype was 48% in gastric cancer cases, 60% in CG patients, and 51% in controls. The prevalence of GSTT1 null genotype was 54% in gastric cancer cases, 48% in CG patients, and 46% in controls. After controlling for age, gender, education, pack-years of smoking, alcohol drinking, body mass index, H. pylori infection, and fruit and salt intake, the adjusted odds ratio (OR) for GSTT1 and gastric cancer was 2.50 (95% confidence interval (CI), 1.01-6.22). When gastric cancer cases were compared with CG patients, the adjusted OR for GSTT1 was 2.33 (95% CI, 0.75-7.25). However, GSTT1 null genotype was not associated with the risk of CG when using population controls. No obvious association was found between GSTM1 and the risk of both gastric cancer and CG. Our results suggest that GSTT1 null genotype may be associated with an increased risk of gastric cancer in a Chinese population.

A biomimetic synthesis of the pauciflorine A and B skeleton

[formula: see text] Racemic minovincine (3), following cyclization, reduction, O-tosylation, fragmentation, and carbamate formation, provided the deoxypauciflorine 12.

[The effect of EDTA with different density on adhesive power of casting post and its scanning electromicroscopy (SEM) observation]

OBJECTIVE:To evaluate the effect of EDTA with different density on adhesive power of casting post.METHODS:Four different density of EDTA(5%,10%,15%,17%)were used to rinse the smear layer of root canal for 60 extracted teeth before they were cemented with ZP;on the other,a SEM observation was made on the rinse of root canal and the combination of adhesive and root canal.Meanwhile,a comparison was also made, after the rinse of EDTA,of tensile strength of casting post after their cement.RESULTS:EDTA with different density have different effect in the rinse of smear layer of root canal,it was proved by both SEM observation and the records of tensile strength of casting post. CONCLUSION:EDTA with density 10% is more effective in both the rinse of smear layer of root canal and the enhancement of adhesive power of casting post.

Anti-Trypanosoma brucei activity of nonprimate zoo sera

Constitutive anti-Trypanosoma brucei subsp. brucei S 427 clone 1 and 22 activities were evaluated in sera from 22 species of nonprimate mammals. The sera fell into 5 categories. Sera from Cape buffalo, giraffe, and greater kudu showed a concentration-dependent inhibition of replication of the 2 clones of organisms, which was dependent on the presence of xanthine oxidase. Sera from warthog and springbok also severely limited trypanosome replication but lacked xanthine oxidase. Their antitrypanosome activity was inactivated by heating at 56 C for 30 min but not affected by absorbing with trypanosomes at 4 C. Sera from lion and leopard showed a concentration-dependent inhibition of the growth of T. brucei S427 clone 1 organisms, but not clone 22 organisms. These sera lacked xanthine oxidase. Their anti-T. brucei S 427 clone 1 activity was inactivated by heating at 56 C for 30 min but not removed by absorbing with trypanosomes. Serum from Grant's gazelle prevented replication of both T. brucei clones, lacked xanthine oxidase, and was not affected by heating at 56 C. Sera from waterbuck, Thompson's gazelle, sitatunga, Cape hartebeeste, gerenuk, Grant's zebra, cow, several cat, cougar, bobcat, and domestic cat were fully supportive of trypanosome replication irrespective of concentration tested up to a maximum of 48% v/v in culture medium. Sera from different individuals of the same mammal species had similar effects on trypanosomes, and samples collected from the same individual at different times also had similar activities indicating species-specific stable expression, or lack thereof, of constitutive serum antitrypanosome components.

[SPE analysis of 4 rodenticides in whole blood and liver by HPLC]

A solid phase extraction (SPE) method has been developed for the analysis of 4 rodenticides: warfarin, couatetralyl, bromadiolone and brodifacoum, using reverse phase high performance liquid chromatograph (HPLC) as determination system. The recovery is 62.6-90.0% (RSD5.1-7.8%) and 37.5-67.7% (RSD5.4%-12.8%) in whole blood and liver sample respectively. The procedure is simple and stable. And the method was confirmed to be effective in the animal experiment.

Identification and characterization of a novel member of the fibroblast growth factor family

A new member of the fibroblast growth factor (FGF) family, FGF-13, has been molecularly cloned as a result of high throughput sequencing of a human ovarian cancer cell library. The open reading frame of the novel human gene (1419 bp) encodes for a protein of 216 a.a. with a molecular weight of 22 kDa. The FGF-13 sequence contains an amino-terminal hydrophobic region of 23 a.a. characteristic of a signal secretion sequence. FGF-13 is most homologous, 70% similarity at the amino acid level, to FGF-8. Northern hybridization analysis demonstrated prominent expression of FGF-13 in human foetal and adult brain, particularly in the cerebellum and cortex. In proliferation studies with BaF3 cells, FGF-13 preferentially activates cell clones expressing either FGF receptor variant, 3-IIIc or 4. The signal transduction pathways of FGF-13 and FGF-2 were compared in rat hippocampal astrocytes. The two FGFs induce an equivalent level of tyrosine phosphorylation of mitogen-activated protein kinase (MAPK) and c-raf activation. However, FGF-13 is more effective than FGF-2 in inducing the phosphorylation of phospholipase C-gamma (PLC-gamma). Treatment of neuronal cultures from rat embryonic cortex with FGF-13 increases the number of glutamic acid decarboxylase immunopositive neurons, the level of high-affinity gamma-aminobutyric acid (GABA) uptake, and choline acetyltransferase enzyme activity. The GABAergic neuronal response to FGF-13 treatment is rapid with a significant increase occurring within 72 h. We have identified a novel member of the FGF family that is expressed in the central nervous system (CNS) and increases the number as well as the level of phenotypic differentiation of cortical neurons in vitro.

Selectivity of post-translational modification in biotinylated proteins: the carboxy carrier protein of the acetyl-CoA carboxylase of Escherichia coli

Biotin-dependent enzymes contain a biotinyl-lysine residue in a conserved sequence motif, MKM, located in a surface hairpin turn in one of the two beta-sheets that make up the domain. A sub-gene encoding the 82-residue C-terminal biotinyl domain from the biotin carboxy carrier protein of acetyl-CoA carboxylase from Escherichia coli as a fusion protein with glutathione S-transferase was created and over-expressed in E. coli. The biotinyl domain was readily released by cleavage with thrombin. Five mutant domains were created in which the conserved MKM motif was systematically replaced: by MAK and KAM, in which the target lysine is moved one place; by KKM and MKK, in which a second potential site for biotinylation is introduced; and by DKA, the motif found in the correspondingly conserved site of lipoylation in the structurally related lipoyl domains of 2-oxo acid dehydrogenase multienzyme complexes. No biotinylation of the MAK or KAM mutants was observed in vivo or by purified biotinyl protein ligase in vitro; in the KKM and MKK mutants, only one lysine residue, presumed to be that in its native position in the hairpin turn, was found to be biotinylated in vivo and in vitro. The DKA mutant was not biotinylated in vivo, but was partly lipoylated and octanoylated. It was also a poor substrate for lipoylation in vitro catalysed by the E. coli lipoyl protein ligase encoded by the lplA gene. The flanking sequence in the MKM motif is important, but not crucial, and appears to have been conserved in part to be compatible with the subsequent carboxylation reactions of biotin-dependent enzymes. The DKA motif, displayed in the hairpin loop, is sufficient to address lipoylation in E. coli but probably by a pathway different from that mediated by the lplA-dependent ligase. The recognition of the structurally homologous lipoyl and biotinyl domains by the appropriate ligase evidently has a major structural component to it, notably the positioning of the target lysine residue in the exposed hairpin loop, but there appear to be additional recognition sites elsewhere on the domains.

[Synthesis and biological activity of substance P analogs]

Substance P (SP) and its three analogs were synthesized through solid-phase procedure. The fully-protected peptide-resin was cleaved with anhydrous HF.--SH of Cys in [Cys5,9] SP(4-11) was protected with Acm, then deprotected through Iodine oxidation method, the disulfide bridge cyclization was formed subsequently. The crude product was purified on C18 RP-HPLC. The results of guinea-pig isolated ileum test (GPI) showed that the potency of the analogs was as follows: [AcGln5, Pro9] SP(5-11) > SP > SP(4-11) > [Cys5,9] SP(4-11). They induced GPI to contract very fast and showed the characteristics of tachykinin. On the writing test in mice, the results showed: [Cys5,9] SP(4-11) > SP > SP(4-11) > [AcGln5, Pro9] SP(5-11). The biological tests showed that the SP analogs have some extent of selectivity.

The trypanocidal Cape buffalo serum protein is xanthine oxidase

Plasma and serum from Cape buffalo (Syncerus caffer) kill bloodstream stages of all species of African trypanosomes in vitro. The trypanocidal serum component was isolated by sequential chromatography on hydroxylapatite, protein A-G, Mono Q, and Superose 12. The purified trypanocidal protein had a molecular mass of 150 kDa, and activity correlated with the presence of a 146-kDa polypeptide detected upon reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid sequences of three peptide fragments of the 146-kDa reduced polypeptide, ligand affinity and immunoaffinity chromatography of the native protein, and sensitivity to pharmacological inhibitors, identified the trypanocidal material as xanthine oxidase (EC 1.1.3.22). Trypanocidal activity resulted in the inhibition of trypanosome glycolysis and was due to H2O2 produced during catabolism of extracellular xanthine and hypoxanthine by the purine catabolic enzyme.

Inhibitory effect of artemether on proteinase of Schistosoma japonicum

AIM

To study the effect of artemether (Art) on the thio proteinase ("hemoglobinase", Hem) of Schistosoma japonicum.

METHODS

Hem was extracted from S japonicum adults. The inhibitory effect of Art on the activity of Hem to degrade human hemoglobin (Hgb) was examined with UV-photometer at 280 nm, SDS-PAGE and scanning at 600 nm on a chromoscanner.

RESULTS

Human Hgb was degraded at pH 4.0 by the Hem. The activities of Hem preincubated at 37 degrees C with Art 0.14, 1.4, and 14 mmol.L-1, were inhibited by 30.2%, 39.8%, and 45.0%, respectively.

CONCLUSION

Art possesses an inhibitory effect to Hem of S japonicum.

Comparison of the exposure characteristics of soft-x-ray film SIOFM-5FW with Kodak 101-05 and Ilford Q-plates

In identical exposure and processing conditions, we compare the exposure characteristics of soft-x-ray film, SIOFM-5FW, with Kodak101-05 and Ilford Q-plates in the soft-x-ray and extreme UV region below 100 nm, using D-19 and Phenisol developers. The experimental results show that for radiation greater than 10 nm, the response of SIOFM-5FW lies between the Kodak101-05 and the Ilford Q-plates but is closer to the former. For radiation of less than 10 nm, the SIOFM-5FW is more sensitive than the Kodak101-05 plate, with a higher saturated optical density, a higher dynamic range, and an obvious carbon K absorption edge structure in the spectra obtained. The effects of the two developers used on the exposure characteristics are discussed.

Myocyte-specific enhancer binding factor 2C expression in fetal mouse brain development

We have previously found that myocyte-specific enhancer binding factor 2C (MEF2C) is expressed in the brain, where it is found at high levels in the developing cerebral cortex. We have now examined MEF2C expression in fetal mouse brain by in situ hybridization and by immunohistochemistry from E11 to E17, the period when most cortical neurons are born. The distribution of MEF2C mRNA detected by in situ hybridization closely resembles that of MEF2C immunoreactivity. MEF2C is not present in proliferative zones in the brain. It is present at high levels in cells that have migrated to the subplate and cortical plate. MEF2C is also found in the olfactory blub at high levels and at lower levels in hippocampus, basal forebrain, striatum, cerebellum, and inferior colliculus, and in some nuclei of the hypothalamus, thalamus and brainstem. The pattern of expression suggests that MEF2C is expressed in a subset of postmitotic neurons in the brain and that it may therefore function to promote terminal differentiation of the cells that express it.

[Effects of endothelin on electrophysiological and contractile activity of guinea pig papillary muscles]

Effects of endothelin on electrophysiological activity and contractility were examined in guinea pig papillary muscle using intracellular microelectrode and contractile tension recording technique. The results indicated that ET-1 prolonged APD, especially PPD and increased the contractile tension in a dose-dependent manner. The ET-induced effects were not influenced by K+ channel blocker TEA, but inhibited by L-type Ca2+ channel blocker nifedipine, ETA receptor selective antagonist BQ-123 and atriopeptin III in a concentration-dependent manner. It is suggested that the changes in electrophysiological activity and the positive inotropic effect induced by ET-1 in guinea pig muscles are due to the elevation of intracellular calcium, which may be mediated by ETA receptor.

Anthraquinones in Rheum palmatum and Rumex dentatus (Polygonaceae), and phorbol esters in Jatropha curcas (Euphorbiaceae) with molluscicidal activity against the schistosome vector snails Oncomelania, Biomphalaria and Bulinus

Hot water extracts of Rheum plamatum and Rheum dentatus (from China) showed molluscicidal activity against the snails Oncomelania hupensis, Biomphalaria glabrata and Bulinus globosus, which are vectors of Schistosoma japonicum, S. mansoni and S. haematobium, respectively. Activity was correlated with antraquinones which were identified by HPLC: rhein and chrysophanol-anthron were most active (> 50% dead snails after 2 days in a 0.03% solution). Molluscicidal activity was intermediate with Rheum-emodin and physcion and was not detectable with cinnamic acid or Aloe-emodin. The snail O. hupensis tended to be more sensitive for several compounds than B. glabrata. Extracts of Jatropha curcas seeds (from Mali) showed molluscicidal activity against both B. glabrata and O. hupensis, the latter being the more sensitive snail. The activity was associated with phorbol esters extracted from Jatropha oil. Of the pure phorbol esters tested, 4 beta-phorbol-13-decanoate killed both snail species at a concentration of 0.001% (10 p.p.m). As Jatropha is locally grown in Mali for other purposes, it might potentially be exploited for schistosomiasis control.

[Ischemic preconditioning and exogenous L-arginine reduce infarct size in rabbit heart]

The effects of NO donor--L-arginine (L-arg) and ischemic preconditioning (IP) on the hemodynamics and myocardial infarct size were examined in the anesthetized rabbit subjected to myocardial ischemia-repefusion to define whether exogenous L-arg could exert a beneficial effect in this pathological model, and whether the L-arg-NO pathway was involved in the cardioprotection provided by IP. The results obtained were as follows: (1) During the course of ischemia (30 min)-reperfusion (180 min), blood pressure, heart rate and myocardial oxygen consumption decreased progressively, and the myocardial infarct size occupied 33.9 +/- 2.4% of the whole left ventricle. (2) The myocardial infarct size could be reduced to 20.1 +/- 2.2% (P < 0.01) by pretreatment with L-arg (300 mg/kg). This myocardial protective effect of L-arg was abolished by NO synthesis inhibitor--Nitro-L-arginine (L-NNA), thereby indicating the involvement of L-arg-NO pathway. (3) IP significantly reduced the infarct size to 21.9 +/- 2.1% (P < 0.01), indicating the prominent cardioprotective effect of such an intervention. Since L-NNA showed no effect on the cardioprotection afforded by IP, it was implied that the L-arg-NO pathway was not involved in the cardioprotective mechanism of IP. (4) Exogenous L-arg might markedly augment cardioprotection provided by IP. The above results strongly suggested that the cardioprotective effect of L-arg on ischemia-reperfused myocardium was mediated by L-arg-NO pathway, which, however, was not involved in the cardioprotection provided by IP.

Evaluation of a monoclonal antibody-based sandwich-ELISA for detection of circulating Schistosoma japonicum antigen (Sj31/32) in an endemic area of China

A sandwich-ELISA specific for 31/32 kDa schistosome proteins was used to trace infections in a Chinese population living in a low endemicity area for schistosomiasis japonica. The study population included 304 persons for whom records were available from 1992 onwards. In 1994, 2 individuals were positive in the miracidial hatching assay performed with 30 g of stools. The ELISA gave positive results for 8 individuals, including these 2 with active infections. Of the remaining 6 ELISA-positive, 5 had excreted eggs and received praziquantel in 1993 and may have harboured residual worms in 1994. It is concluded that this ELISA is able, in a low prevalence situation, to identify the few infected individuals.

Schistosoma japonicum, S. mansoni, S. haematobium, S. intercalatum, and S. rodhaini: cysteine-class cathepsin activities in the vomitus of adult worms

Vomitus from adults of five Schistosoma species was screened for biochemical homologues of the mammalian cysteine proteinases cathepsins B, H, and L. Bovine cathepsin B and rat cathepsin L served as references. Using the substrate Arg-NMec, a schistosome cathepsin H-like activity was never detected. All species degraded the cathepsin B substrate Z-Arg-Arg-NMec, but distinct species differences were observed with respect to pH optima and buffer preferences. The cathepsin B and L substrate Z-Phe-Arg-NMec was similarly degraded by all species, and activity was abolished by the cysteine proteinase inhibitor E-64. Preferences by vomitus proteinase activities for Z-Phe-Arg-NMec over Z-Arg-Arg-NMec were similar to or higher than those found for bovine cathepsin B but well below those observed for rat cathepsin L; also, the preferential cathepsin L inhibitor Z-Phe-PheCHN2 only partially inhibited proteinolytic activity. The results suggest the possible presence in vomitus of a minor cathepsin L-like activity and demonstrate a major cathepsin B-like activity that is biochemically variable between schistosome species.

Affinity chromatography of trypsin using chitosan as ligand support

Chitosan beads were prepared for use as affinity adsorbent carrier. The affinity ligand, chicken ovomucoid, was immobilized on the chitosan via a cross-linker, glutaraldehyde. The results showed that 60 mg chicken ovomucoid could be immobilized on l g chitosan, and the maximum binding capacity for trypsin was about 8.10(4) U/g dry adsorbent. The procedure for preparing the chitosan-based affinity adsorbents was much safer and simpler than when a Sepharose-based matrix was the support. Columns packed with the affinity adsorbents were employed for trypsin chromatography. The experimental results revealed that the affinity adsorbents possessed good mechanical strength and storage stability and could be also operated repeatedly. Chitosan was suitable for use as an affinity adsorbent support for laboratory-scale and large-scale purification.

[Cardiovascular effects and underlying mechanisms of adenosine and its analogues]

The present work was aimed to define the cardiovascular effects and underlying mechanisms of adenosine and its analogues. The results showed that (1) adenosine and 2-chloroadenosine could induce an initial increase in MAP mediated by the adenosine A2 receptors in carotid body chemoreceptor, and a subsequent decrease in MAP, being attributed to the adenosine A1 receptors in heart and A2 receptors in blood vessels; (2) N6-cyclopentyladenosine (CPA, a selective adenosine A1 receptor agonist) inhibited the electrophysiological activity of pacemaker cells in sinoatrial node; (3) CPA markedly attenuated the development of early afterdepolarization, delayed afterdepolarization and triggered activity induced by isoproterenol; (4) endogenous adenosine might play an important role in the generation of anoxic bradycardia; (5) activation of adenosine receptors along with an increase in adenosine receptor density during the course of ischemic preconditioning might provide the protective effect on the ischemic heart injury; (6) the cardiovascular effects of adenosine and its analogues were mainly mediated by activation of ATP sensitive K+ channels coupled to adenosine receptors.

[Endothelin and ATP-sensitive potassium channel mediate electrophysiological changes induced by hypoxia in rabbit sinoatrial node]

The role of ET and KATP channel in hypoxia-induced negative chronotropic effect of pacemaker cells in rabbit sinoatrial node was studied with intracellular microelectrode technique. The results obtained were as follows: (1) Hypoxia produced a progressive decrease in the velocity of diastolic depolarization (VDD) of pacemaker cells resulting in a reduced rate of pacemaker firing (RPF), and induced a decrease in APD, especially APD50. (2) KATP channel opener cromakalim markedly induced a negative chronotropic effect in a concentration-dependent manner and significantly shortened APD50. KATP channel blocker glibenclamide alleviated the effects of hypoxia on pacemaker cells, thereby suggesting the involvement of KATP channel in the hypoxia-induced effects. (3) By superfusion of ET-1, the hypoxia-induced decrease in RPF was remarkably potentiated and the occurrence of pacemaker arrest was shifted to an earlier time. The hypoxia-induced effects could be effectively attenuated after pretreatment with BQ-123, implying the role of endogenous ET-1 release in hypoxia-induced effects. It is concluded that the negative chronotropic effect and the decrease in APD induced by hypoxia may be attributed to the activation of KATP channel and the release of endogenous ET.

Phenolic and triterpenoid glycosides from Aster batangensis

A new phenolic glycoside, asterbatanoside A [p-hydroxyacetophenone-4-O-beta-D-xylopyranosyl-(1-->6)-beta-D- glucopyranoside], and two new triterpenoid saponins, asterbatanoside B [2 alpha,3 beta,23-trihydroxyolean-12-en-28-oic acid-28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside] and asterbatanoside C [3-O-beta-D-glucopyranosyl-2 beta,3 beta,23-trihydroxyolean- 12-en-28-oic acid-28-O-beta-D-glucopyranoside] were isolated from the roots of Aster batangensis. Their structures were determined by spectroscopic methods and chemical evidence. The total synthesis of asterbatanoside A is also reported.

[Effects of endothelin on the electrical activity of sino-atrial pacemaker cells of rabbit]

The effects of endothelin-1 (ET-1) on the electrophysiological activity of pacemaker cells of rabbit sino-atrial node were examined by using intracellular microelectrode technique. The results obtained were as follows: (1) With superfusion of ET-1 (1-30 nmol/l), the velocity of diastolic depolarization (VDD) of pacemaker cells was significantly decreased in a concentration dependent manner, resulting in a reduced rate of pacemaker firing (RPF). (2) The decreases in RPF and VDD induced by ET-1 could be virtually blocked by pretreatment with ET(A) receptor blocker BQ-123 (20 or 100 micrograms/L). It was strongly suggested that the electrophysiological effects of ET-1 on the pacemaker cells were mediated by the ET(A) receptor. (3) The negative chronotropic action of ET-1 on the pacemaker cells was totally abolished by pretreatment with a kind of KATP channel blocker glibenclamide (10 mumol/L). On the basis of above results, it appears that the binding of ET-1 with ET(A) receptor may induce an activation of KATP channels with resultant increase in K+ current so as to decrease the velocity of diastolic depolarization in the pacemaker cells.

Circulating antigens in schistosomiasis: detection of 31/32-kDa proteins in sera from patients infected with Schistosoma japonicum, S. mansoni, S. haematobium, or S. intercalatum

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to detect 31/32-kDa schistosome proteins as circulating antigens in sera from schistosomiasis patients. A monoclonal antibody was used as a capture antibody and rabbit antiserum raised against purified 31/32-kDa proteins was the detecting antibody. Positive results were obtained with patients infected with Schistosoma japonicum (88%; n = 69), S. mansoni (80%; n = 56), S. haematobium (100%; n = 40), or S. intercalatum (94%; n = 65). Sera from uninfected Chinese and African individuals and from Chinese patients with trichinosis, cysticercosis, or paragonimiasis did not react in the assay. This ELISA appears to be valuable in diagnosing infections by all major human schistosome species.

Preliminary report on treatment of bone tumors with microwave-induced hyperthermia

Between July, 1992, and February, 1995, 62 patients with various bone tumors were treated with microwave-induced hyperthermia. The series had 47 cases of malignant tumors and 15 cases with benign tumors; most of the tumors occurred at or near knee joints (53/62 = 85.4%). The surgical procedure consisted of separating the tumorous segment from surrounding normal tissues with a safe margin, cooling the normal tissues (including the vital neurovascular bundle and the intrajoint structures) with a water circulation system while heating the tumor simultaneously with the microwave antenna array, and providing an adequate soft-tissue cover for the dead bone. The tumor core temperature and the surface temperature reached 108 and 65 degrees C, respectively. The duration of microwave irradiation was usually 40-50 minutes. Meanwhile, the temperature of the normal tissues was kept under 39 degrees C. The minimal and maximal periods of clinical observation were 3 months and 36 months, respectively, and the mean follow-up period was 17 months. The 62 cases were evaluated from both oncological and orthopedic points of view. Five cases had local recurrence and required amputation. The 57 other cases had excellent local control. Six malignancy cases died of lung metastasis during a period of 1-2 years. Pathological fracture occurred at devitalized bone in five cases. In most of the cases, the knee joints functioned well, were stable and painless, and had almost full range of motion. Single-photon emission-computed tomography study in 16 cases revealed that revascularization of the devitalized tumorous bone segment could be accomplished in 1 year or more. These results show that the use of microwave hyperthermia for the treatment of bone tumors can be considered to be a definitive operation procedure that is safe and is well tolerated by patients. The oncological and orthopedic results are very encouraging.

[Synthesis and antimicrobial activities of tetrahydro-2H-1,3,5-thiadiazine-2-thiones]

Ten 3-benzyl-5-substitued tetrahydro-2H-1,3,5-thiadiazine-2-thiones were synthesized and seven of them are reported for the first time. The structures of the compounds have been elucidated by UV, IR, H-NMR and elemental analysis. The in vitro activity of the compounds against 6 kinds of bacteria and 2 kinds of fungi was tested. The antimicrobial activities of all compounds are more potent than sulfadiazine sodium and less potent than norfloxacini. All compounds were found to be more active against gram-negative and less active against gram-positive bacteria and weak against fungi.

Protective effect of preconditioning on ischemic heart and characterization of adenosine receptors in ischemic rabbit hearts

AIM

To assess the role of adenosine receptors in the cardioprotective effect of preconditioning and the characterization of adenosine receptors in heart.

METHODS

In 18 anesthetized rabbits, myocardial ischemia was induced by occlusion of left descending coronary artery. ST segment elevation in epicardial electrogram was used as a criterion of acute ischemic injury. Myocardial adenosine receptors were measured using [3H] adenosine ligand.

RESULTS

After 60-min ischemia, epicardial ST segment elevation was higher in ischemia group (13.9 +/- 0.6 mV) than in the ischemic preconditioning group (3.1 +/- 0.5 mV). In membranes of the ventricular myocytes prepared from ischemic-preconditioning group, the density of adenosine receptors was higher than that of ischemia and sham ischemia groups (Bmax being 602 +/- 40, 348 +/- 28, and 335 +/- 30 pmol/g protein, respectively). Affinity of the receptors for the [3H] adenosine was not different in the 3 groups (Kd being 181 +/- 18, 169 +/- 21, and 196 +/- 24 nmol . L-1, respectively).

CONCLUSION

Activation of adenosine receptors along with an increase in adenosine receptor density during ischemic-preconditioning provides the basis for adenosine to exert its protective effect on the ischemic heart.

Hemodynamic effects of centrally administered adrenomedullin (13-52) in anesthetized rats

This study was conducted to investigate the effect of intracerebroventricular administration of adrenomedullin (13-52) [ADM(13-52)], a novel hypotensive peptide, on the hemodynamic parameters of anesthetized rats. ADM(13-52) was administered centrally in a dose of 0.4-3.2 nmol/kg. It provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure, heart rate, stroke volume, cardiac index, left ventricular pressure, left ventricular dp/dtmax and dp/dtmin, but reduction in total peripheral resistance index. In addition, intracerebroventricular administration of ADM(13-52; 1.6 nmol/kg) provoked a marked increase in renal sympathetic nerve activity. Intracerebroventricular administration of artificial cerebrospinal fluid had no effect on the hemodynamic parameters and renal sympathetic nerve activity. The results indicate that ADM(13-52) exerts a central action on the cardiovascular system. The mechanisms of hemodynamic changes induced by central ADM(13-52) were preliminarily analyzed in this study. ADM might play a role in the central control of the cardiovascular system, although the confirmed mechanisms and the physiological implications are undetermined.

[Investigation of cervical Chlamydia trachomatis infection in gynecologic outpatients]

A group of 662 women in our gynecologic OPD were screened for Chlamydia trachomatis with direct immunofluorecence monoclonal antibody (DFA) staining technique. Their age distribution ranged from 16 to 60 years old. The overall positivity rate was 26.3%. Of the 269 pregnant women, 64 cases were found to have Chlamydia trachomatis infection, an infection rate of 23.74%. There was no statistically significant difference of infection rates among age groups. In the positive group, however, the rate of infertility was 25.43%, much higher than that in the negative group (12.88%, P < 0.01). And there was no statistical significance of infection rates between patients taking contraception and those did not. A positive correlation existed between the degree of cervicitis and the Chlamydia trachomatis infection.

Overexpression of MDM-2 mRNA and mutation of the p53 tumor suppressor gene in bladder carcinoma cell lines

To investigate the importance of oncogenes and tumor suppressor genes in bladder carcinogenesis, we determined the status of the expression of the MDM-2 and p53 genes and genetic alterations in the p53 gene in five bladder carcinoma cell lines and one kidney urothelial carcinoma cell line. Overexpression of MDM-2 mRNA was observed in three bladder carcinoma cell lines, J82, SCaBER, and BFTC-905. Amplification of the MDM-2 gene was not detected in any of the six cell lines by southern analysis. The deletion in the p53 gene was observed in J82, and point mutation was detected in J82 and BFTC-909, the kidney urothelial carcinoma cell line. In contrast, no mutations were found in codons 12, 13, and 61 in the Ha-ras and Ki-ras genes in these six cell lines. These results indicate that alterations in the p53-regulated pathway are important in bladder carcinogenesis.

Effects of N6-cyclopentyladenosine on afterdepolarizations and triggered activity induced by isoproterenol in guinea pig papillary muscle

AIM

To investigate the effects of N6-cyclopentyladenosine (CPA, selective adenosine A1 receptor agonist) on afterdepolarizations and triggered activity induced by isoproterenol (Iso) in guinea pig papillary muscle.

METHODS

The stable and reproducible early afterdepolarization (EAD) and delayed afterdepolarization (DAD) of guinea pig papillary muscle were induced by Iso 50 nmol.L-1. The parameters of EAD and DAD were recorded using intracellular microelectrodes.

RESULTS

CPA markedly attenuated the development of EAD, DAD, and triggered activity (TA) induced by Iso in guinea pig papillary muscle. The inhibitory effects of CPA on Iso-induced EAD and DAD were antagonized by 8-phenyltheophylline (8-PT) and glibenclamide (Gli).

CONCLUSION

ATP-sensitive K+ channels were involved in Iso-induced EAD and DAD, and in the inhibitory effects of CPA on EAD and DAD.

A serotypic study of hemorrhagic fever with renal syndrome in rural China

Apodemus agrarius was trapped in the fields and Rattus norvegicus was trapped within the houses in the villages of Jiande County, a region in the Zhejiang Province of China endemic for hemorrhagic fever with renal syndrome (HFRS). Antibodies to hantaviruses were detected in three (16.7%) of 18 A. agrarius and 12 (13.5%) of 89 R. norvegicus, whereas hantavirus antigens were detected in the lung tissues of four (22.2%) of 18 and nine (10.1%) of 89 of these rodents, respectively. Three hantaviruses, one from A. agrarius and two from R. norvegicus, were isolated and found to be antigenically similar to Hantaan and Seoul serotype viruses, respectively. A serologic study of 437 clinically defined HFRS patients conducted in Jiande County in 1988 revealed that the ratio of Hantaan (72.5%) to Seoul (26.8%) serotype virus infections was 2.7:1. Two epidemic seasons were found, with a major peak in November and a minor peak in June, and both were associated with Hantaan serotype virus infections that coincided with two seasonal peaks of the A. agrarius population and local agricultural activities in the fields. Seoul serotype virus infections occurred with a small peak during the months of December through May, in which in-house activities were dominant. All data suggested that Jiande County was an area endemic for HFRS, predominantly of the Hantaan virus serotype, combined with Seoul serotype virus infections.

Endogenous adenosine and ATP-sensitive potassium channel modulate anoxia-induced electrophysiological changes of pacemaker cells in sinoatrial node of guinea pigs

AIM

To investigate the electrophysiological effects of adenosine deaminase (ADase, an enzyme converting adenosine to inosine and ammonia), 8-phenyltheophylline (8-PT, a nonselective antagonist of adenosine receptors) and glibenclamide (Gli, a potent blocker of ATP-sensitive K+ channels) on anoxic pacemaker cells of SA node.

METHODS

Anoxia of pacemaker cells in SA node of guinea-pig was induced by perfused for 20 min with a modified K-H solution gassed with 100% N2 deprived of glucose. Parameters of action potentials including maximal diastolic potential (MDP), amplitude of action potential (APA), duration of 90% repolarization (APD90), maximal rate of depolarization (Vmax), rate of pacemaker firing (RPF), and velocity of diastolic (phase 4) depolarization (VDD) were recorded using intracellular microelectrodes.

RESULTS

Anoxia increased MDP, APA, and Vmax and decreased VDD, RPF in a time-dependent manner. ADase 10 U.L-1, 8-PT 0.1 mumol.L-1 and Gli 10 mumol.L-1 significantly attenuated the electrophysiological changes of pacemaker cells in sincatrial node induced by anoxia.

CONCLUSION

Endogenous adenosine and ATP-sensitive K+ channels may play an important role in the generation of anoxic bradycardia in guinea pigs.

Retrospective and prospective studies of hemorrhagic fever with renal syndrome in rural China

Residents of two villages in Zhejiang Province, China, were interviewed and serum samples were collected to assess prevalence of hantavirus infection. Antibody prevalence was 12% (219/1811), with a ratio of illness to infection of 1.0:5.4. Seroprevalence increased with age, but no association was found with sex. There was also no evidence of vertical transmission. One year later, 2.3% (30/1325) of seronegative subjects had seroconverted including 2 who had hemorrhagic fever with renal syndrome. Peak incidence of infection occurred in those 15-39 years old. Hantaan was the dominant serotype; Seoul serotype was less common (5:1). Host reservoirs were Apodemus agrarius in agricultural fields and Rattus norvegicus in houses. Risk factors for infection were traces of rat-contaminated food, travel to other areas for farm work, direct rodent contact, camping in grain fields, living in a house on the periphery of a village, stacking straw stacks outside houses, and keeping cats. All may provide exposure to infectious rodent reservoirs.

Metabolism of polynuclear aromatic hydrocarbon in human term placenta influenced by cigarette smoke exposure

The relative contributions of biologic and environmental factors on embryo-fetal development were elucidated in a population of pregnant women who were exposed to varying amounts of active cigarette smoke and women who were not exposed to cigarette smoke. The neonatal weight at birth, placental weight at delivery, duration of pregnancy, and placental xenobiotic (polynuclear aromatic hydrocarbon, PAH) metabolism potential were assessed in this population. The overall metabolic capability in exposed and unexposed placental tissue was measured by in vitro assays using microsomes and a PAH substrate, benzo[a]pyrene (B[a]P). Toxicity potential was determined by B[a]P-metabolite-DNA adduct generation under the same incubation condition. Cigarette smoke exposure increased the overall PAH metabolism potential in placental tissues by approximately 200% (nonsmoker 176.2 +/- 33.6, n = 25; smoker 524.5 +/- 75.5, n = 32 pmol/mg protein) whereas PAH-DNA adduct formation potential did not increase significantly over the basal level (nonsmoker 5002 +/- 830, n = 15; smoker 6172 +/- 1443, n = 22 fmol B[a]P equivalent/mumol DNA/mg protein). Exposure to cigarette smoke during pregnancy is deleterious to fetal development as reflected by reduced neonatal weight at birth. In contrast, placental weight reduction is indistinct, but placentae expressed markedly augmented overall xenobiotic (PAH) metabolism capability in response to cigarette smoke exposure during pregnancy, indicating placental metabolism may be an important mediator of adverse effects induced by such xenobiotic exposure.

[Correlation between bronchoalveolar lavage fluid angiotensin converting enzyme levels and T cell subsets in patients with sarcoidosis]

BALF ACE levels were assayed in patients with sarcoidosis, and their correlation with lymphocyte percentage and TH/Ts ratio in BALF were analysed. The results showed a positive correlation (r = 0.4453, P < 0.05; r = 0.7085, P < 0.01). BALF ACE level was decreased as patients with active sarcoidosis improved clinically, indicating that BALF ACE level may be a sensitive biological parameter in the diagnosis and disease activity assessment of sarcoidosis.

Detection of Schistosoma japonicum antigen (Sj31/32) in sera of Chinese patients using a sandwich ELISA based on monoclonal antibody

A sandwich-ELISA was developed using IgG from rabbits infected with Schistosoma japonicum as capture antibody and a monoclonal antibody as detecting reagent for circulating Sj 31/32 in patient sera. The assay detected circulating antigen in 36 of 53 sera from Chinese schistosomiasis japonica patients, but not in sera from healthy persons or patients with paragonimiasis, trichinosis or cysticercosis. This is the first demonstration that Sj 31/32 proteins may be used for circulating antigen-based serodiagnosis of schistosomiasis.

[Tumor microvascular bed and its reactivity to vasoactive agents: measurement of tissue blood flow and patho-morphological study]

Structural characteristics of tumor microvascular bed and its reactivity to vasoactive agents were studied by histological and ultrastructural examination and tissue blood flow measurement. The results showed that newly formed vessels in the tumor tissue consisted of a single layer of endothelial cells with multi-layer basement membranes and a few pericytes. Smooth muscle cells and nerve endings were absent. The tissue blood flow in highly proliferative parts of tumors was relatively constant and not influenced by tumor size, even though the distribution of neovasculature in tumor tissue was very uneven in distribution. The only vasoactive agent which can selectively increase the tumor blood flow was angiotensin II, whereas other adrenergic vasoconstrictors did not show this action.

Electrophysiological effects of N6-cyclopentyl-adenosine and [-]-N6-[phenylisopropyl]-adenosine on pacemaker cells in sinoatrial node of guinea pigs

The electrophysiological effects of N6-cyclopentyladenosine (CPA) and [-]-N6-[phenylisopropyl]adenosine (R-PIA) (both are selective adenosine A1 receptor agonists) on pacemaker cells in sinoatrial (SA) node of guinea pigs were investigated using intracellular microelectrodes. CPA and R-PIA increased the amplitude of action potential, amplitude of the maximal diastolic potential and maximal rate of depolarization (phase 0), but decreased the velocity of diastolic (phase 4) depolarization, the rate of pacemaker firing, and the duration of 90% repolarization in pacemaker cells of guinea pigs. 8-Phenyltheophylline (a nonselective antagonist of adenosine receptors) and glibenclamide (a potent blocker of ATP-sensitive K+ channels) inhibited the electrophysiological responses of pacemaker cells to CPA. These results suggest that the electrophysiological changes induced by CPA are adenosine receptor-dependent and mainly mediated by activation of ATP-sensitive K+ channels coupled to adenosine receptors.

[A histogenetic study on the carcinogenesis of colonic mucous membrane glands induced by 1,2-dimethylhydrazine in rats]

The relationship between atypical proliferation and carcinogenesis of colonic mucous membrane glands induced by different doses of 1,2-dimethylhydrazine (DMH) was studied by use of histopathological methods and sequential endoscopic observation. The results showed a significant increase of atypical glands in the flat mucosa with the increase in number of DMH injections, the degree of atypical proliferation becoming more serious with the increase of glandular ducts. The following changes were observed under sequential endoscopy: small elevations were first seen on the flat mucosa, then in sequence-flat elevations, hemisphere elevations, substem elevations and finally, stemmed elevations. At the same time, changes such as rubifaction, erosion, central depression and hemorrhage on the tumor surface were frequently encountered. It is concluded that atypical glandular proliferation in the flat mucosa of the colon is a precancerous lesion of colonic carcinoma.

Immunization of pigs against infection with Schistosoma japonicum using ultraviolet-attenuated cercariae

Since pigs are important in the zoonotic transmission of schistosomiasis japonica in China, a veterinary vaccine might contribute to the control of the disease in humans. Pigs were immunized with three doses each of 10,000 cercariae of Schistosoma japonicum attenuated with ultraviolet light (400 microWatt.min/cm2). The experiment was performed with portable irradiation equipment in a rural area of the Hubei Province (P.R. China). A challenge infection of 1,000 untreated cercariae was given 2.5 or 6 months after the last immunization, and age-matched naive pigs were challenged as a control. Immunized pigs developed about 90% resistance against the challenge. The liver egg load of these animals was reduced by over 90%. Less than 0.01% of the immunizing cercariae developed to adult parasites and the vaccination had no apparent adverse influence on the pigs' health.

Augmentation of polynuclear aromatic hydrocarbon metabolism of human placental tissues of first-trimester pregnancy by cigarette smoke exposure

OBJECTIVE

Polynuclear aromatic hydrocarbons are important components of cigarette smoke. The toxicity of polynuclear hydrocarbons depends on their metabolic biotransformation by tissues. This study was performed to assess the effects of cigarette smoke exposure on polynuclear aromatic hydrocarbon metabolism in the human placental tissues of first-trimester pregnancy.

STUDY DESIGN

The expression of essential enzymes that metabolize polynuclear aromatic hydrocarbons and regulate toxic metabolism, aryl hydrocarbon hydroxylase, epoxide hydrolase, and glutathione S-transferase, were determined by immunocytochemical staining of the specific enzymes in first-trimester placental samples from both smoker and nonsmoker donors. The overall polynuclear aromatic hydrocarbon metabolism by such tissues was quantitated by a radiometric assay with benzo[a]pyrene substrate in placental villi tissues and also in isolated trophoblast cells or in cultured trophoblast cells in the presence of polynuclear aromatic hydrocarbon agent.

RESULTS

Immunocytochemical staining revealed that aryl hydrocarbon hydroxylase was localized on trophoblast cells of first-trimester placentas from smoker donors. Epoxide hydrolase was present in stromal and trophoblast cells, and glutathione S-transferase (pi) was present in trophoblast cells of both nonsmoker and smoker subjects. In addition, the overall metabolism of polynuclear aromatic hydrocarbon xenobiotics in such tissues (8 to 11 weeks) of donors who smoked cigarettes was observed to be increased compared with that of nonsmokers by radiometric assay of metabolic products. The increased polynuclear aromatic hydrocarbon metabolism from such exposure was also shown in isolated and purified trophoblast cells of first-trimester placental villi and in culture of such trophoblast cells of nonsmoker donors with polynuclear aromatic hydrocarbon by the same assay procedure.

CONCLUSIONS

Therefore, contrary to previous assumptions, these data demonstrate that cigarette smoke exposure increases the polynuclear aromatic hydrocarbon metabolism of placentas even during the early stages of pregnancy. Augmented polynuclear aromatic hydrocarbon metabolism may produce genotoxic metabolites deleterious to conceptus development.