(3 + 2)-Dimensional superspace approach to the structure of the stage-2 misfit layer compound (SbS)1.15(TiS2)2

The inorganic misfit layer compound (SbS)1.15(TiS2)2 was prepared by high-temperature reaction of the elements. It can be regarded as a stage-2 phase intercalation compound where double layers of SbS are inserted into the van der Waals gaps of TiS2 with stacking sequence ...[TiS2][SbS][TiS2][TiS2][SbS][TiS2].... The structure, determined by single crystal X-ray diffraction on the basis of the (3 + 2)-dimensional superspace group C{\bar 1}, is described by two interpenetrating, incommensurately modulated subsystems. The first subsystem comprises double sandwiches of TiS2 with 1T-TiS2 structure. The lattice parameters are a 11 = 3.404 (1), a 12 = 5.908 (3), a 13 = 17.068 (3) Å, α 1 = 86.28 (2), β 1 = 96.40 (2) and γ 1 = 90.00 (2)°. The second subsystem is built of intrinsically interface modulated double layers of SbS. Unit-cell dimensions of the basic structure are given by a 21 = 2.950 (1), a 22 = 5.932 (2), a 23 = 17.008 (2) Å, α 2 = 85.82 (1), β 2 = 85.30 (1), γ 2 = 84.11 (1)°. The interface modulation wavevector of SbS is given by q = 0.411 (2)a*21 + 0.822 (4)a*22. The two subsystems have the common (a* v2, a* v3) plane. Refinement on 3112 reflections with I > 2.5σ(I) converged to R = 0.088 (wR = 0.108). The structure consists of both occupational and displacive modulations for the atoms in the SbS subsystem. The SbS subsystem has the same structural features as found in the compound (SbS)1.15TiS2 [Ren, Meetsma, Petricek, van Smaalen & Wiegers (1995), Acta Cryst. B51, 275–287]. But stacking disorder of SbS is found corresponding to displacements of the layers along the a 21 axis; the final structure model involves a rigid shift of 0.63 (2) Å of 5.5 (4)% of SbS to both sides along a 21.

Vacancies and electron localization in the incommensurate intergrowth compound (La0.95Se)1.21VSe2

The structure of the inorganic misfit layer compound (La0.95Se)1.21VSe2 has been determined on the basis of a four-dimensional superspace group. The crystal is composed of an alternate stacking of VSe2 sandwiches and two-atom-thick LaSe layers. The first subsystem VSe2 has a distorted CdI2-type structure with V atoms in trigonal antiprisms of Se atoms. It has space-group symmetry C{\bar 1} and its basic structure unit-cell dimensions are a 11 = 3.576 (3), a 12 = 6.100 (2), a13 = 11.690 (2) Å, α 1 = 95.12 (2), β 1 = 85.96 (2) and γ = 89.91 (2)°. The second subsystem LaSe has a distorted rock-salt structure with space-group symmetry C{\bar 1} and a basic structure unit cell given by a 21 = 5.911 (2), a 22 = 6.101 (2), a 23 = 11.684 (2) Å, α 2 = 95.07 (2), β 2 = 85.76 (2), γ 2 = 90.02 (2)°. The two subsystems have the common (a* ν2, a* ν3) plane and have a displacive modulation according to the two mutually incommensurate periodicities along the v1 axes. The symmetry of the complete system is described by the superspace group Gs = C{\bar 1} [0.6050 (7), 0.0020 (7), −0.007 (1)] with C-centring (½,½, 0, ½). Reciprocal lattice parameters for this superstructure embedding are (a * 1, a * 2, a * 3, a * 4) = (a * 11, a * 12, a * 13, a * 21). For 2125 unique reflections with I> 2.5σ(I), measured using Mo Kα1 radiation, refinement smoothly converged to wR = 0.055 (R = 0.045) on a modulated structure model with 77 parameters including La vacancies. The presence of ~ 5% of La vacancies in the LaSe subsystem leads to an exact charge balance between La3+, V3+ and Se2−. The largest modulation occurs on the V atoms, which results in strong variation in the V—V distances. Thus, the semiconducting behaviour of this compound is interpreted in terms of La vacancies in LaSe and modulation-induced Mott localization in VSe2.

Semipreparative chromatographic separation of cyclosporin G metabolites generated by microsomes from rabbits treated with rifampicin

An efficient drug-induced rabbit liver microsomal enzyme system, that may be easily scaled up, has been applied to produce milligram (mg) quantities of cyclosporin G metabolites (CMs). Using hepatic microsomal preparations from rabbits pretreated with rifampicin (RIF) and a NADPH regenerating system, we converted 60% of the cyclosporin G (CsG) to 12 CMs in 2 hr. CMs were recovered by solid-phase extraction. Separations performed on a semipreparative scale with two sequential 250 x 10 mm reversed-phase HPLC columns yielded mg quantities of CMs. The yield of GM1 and GM9 obtained by a single HPLC separation step was estimated to be 1585 +/- 103 micrograms and 648 +/- 33 micrograms, respectively. Other CMs produced by this microsomal enzyme system were GM19, GM4N, GM1c, the aldehydic isomers (GM1cAL and GM1AL), GM14N, GM4N9, GM1A, and GM1cA. The purity of CMs was confirmed by analytical HPLC and their molecular weights (M.W.) were determined by Fast Atomic Bombardment Mass Spectrometry (FABMS). Biotransformation of CsG and cyclosporine (CsA) was also compared using this in vitro model system. Significant difference was found between the rate of aldehydic metabolite formation from CsG and that from CsA. This translates to a faster rate of AM1cAL and AM1AL formation than that of GM1cAL and GM1AL. In addition, the rate of CsG conversion to GM9 appears to be faster than that of CsA conversion to AM9.

Overexpression of human nucleolar proteins in insect cells: characterization of nucleolar protein p120

Nucleolar p120 is a proliferation-associated protein, which becomes detectable early in the G1 phase of the cell cycle and peaks early in the S phase. A variety of human malignant tumor cells contain much higher levels of p120 than normal resting cells. The cellular functions of p120 are unknown, and little information is available on the structural characteristics of the human p120 protein. For biochemical characterization, human p120 protein was expressed in a baculovirus system and purified to approximately 95% purity. By indirect immunofluorescence, most of the recombinant human p120 as well as recombinant human B23, C23, or fibrillarin were localized to insect cell nucleoli and to large globular nuclear inclusions. Like endogenous p120 in HeLa cells, recombinant p120 expressed in insect cells was phosphorylated. On sucrose density gradients, p120 from HeLa cells sedimented in the 60-80S region, in which preribosomal particles sedimented using similar extraction and centrifugation procedures. The sedimentation of p120 shifted to the 5-10S region by treatment with 1 M KCl or with RNAse which suggests that p120 is bound to RNA.

Angiotensin II action in isolated microperfused rabbit afferent arterioles is modulated by flow

We have recently presented evidence that endogenous nitric oxide (NO) and prostaglandins (PGs) modulate angiotensin II (Ang II) action in microperfused afferent arterioles (Af-Arts). Because flow may be a physiological stimulus of endothelial release of NO and PGs, we tested the hypothesis that flow through the lumen of the Af-Art stimulates the endothelium to produce NO and PGs, which in turn modulate the action of Ang II. We microdissected the terminal segment of an interlobular artery together with two Af-Arts, their glomeruli and efferent arterioles (Ef-Art). The two Af-Arts were perfused simultaneously from the interlobular artery, while one Ef-Art was occluded. Since the arteriolar perfusate contained 5% albumin, oncotic pressure built up in the glomerulus with the occluded Ef-Art and opposed the force of filtration, resulting in little or no flow through the corresponding Af-Art. Thus this preparation allowed us to observe Ang II action in free-flow and non-flow Af-Arts simultaneously. Ang II-induced constriction was weaker in free-flow than non-flow Af-Arts, with the luminal diameter decreasing by 8 +/- 2% and 23 +/- 3% at 10(-9) M, respectively (P < 0.013 free-flow vs. non-flow; N = 9). Disrupting the endothelium augmented Ang II action in free-flow (33 +/- 5.1%; P < 0.01 vs. intact endothelium) but not non-flow Af-Arts (31 +/- 5.3%), thus abolishing the differences between them (N = 8). Pretreatment with an inhibitor of either NO synthase (N-nitro-L-arginine methyl ester) or cyclooxygenase (indomethacin) augmented Ang II action more in free-flow than non-flow Af-Arts, likewise abolishing the differences between them. These results suggest that intraluminal flow modulates the vasoconstrictor action of Ang II in Af-Arts via endothelium-derived NO and PGs. Thus flow may be important in the fine control of glomerular hemodynamics.

Platelet-activating factor dilates efferent arterioles through glomerulus-derived nitric oxide

Despite evidence that platelet-activating factor (PAF) is produced by the glomerulus, its direct action on the glomerular microcirculation is poorly understood. It was recently reported that at picomolar concentrations, PAF dilates isolated microperfused afferent arterioles (Af-Art) via nitric oxide (NO). The present study tested the hypothesis that PAF acts on the glomerulus to release NO, which in turn controls the resistance of the efferent arteriole (Ef-Art). Rabbit Ef-Art were perfused from the distal end (retrograde perfusion [RP]) to eliminate the influence of the glomerulus, or through the glomerulus from the end of the Af-Art (orthograde perfusion [OP]) to maintain the influence of the glomerulus. Ef-Art were preconstricted by approximately 40% with norepinephrine and increasing doses of PAF were added to both the arteriolar perfusate and bath. Only with OP did PAF at picomolar concentrations cause significant dilation: at 400 pmol, the diameter increased by 64 +/- 11% from the preconstricted level (N = 6, P < 0.01). This dilation was completely abolished by pretreatment with an NO-synthesis inhibitor. To study its possible constrictor action, PAF was added to nonpreconstricted Ef-Art. At nanomolar concentrations, PAF constricted Ef-Art similarly in both RP and OP: at 40 nM, the diameter decreased by 24 +/- 4% (N = 6, P < 0.01) and 20 +/- 2% (N = 6, P < 0.01), respectively. This constriction was attenuated by pretreatment with indomethacin (Indo) in both RP (14 +/- 2%, N = 7; P < 0.02 versus without Indo) and OP (10 +/- 2%, N = 6; P < 0.02 versus without Indo).

IN CONCLUSION

(1) at picomolar concentrations, PAF stimulates the glomerulus to release NO, which in turn dilates the Ef-Art; and (2) at nanomolar concentrations, PAF constricts the Ef-Art partly through release of cyclooxygenase metabolites. Thus, PAF may play a role in glomerular hemodynamics under various physiological and pathological conditions.

Topology of prostaglandin H synthase-1 in the endoplasmic reticulum membrane

Prostaglandin H synthase-1 is an integral endoplasmic reticulum membrane protein which catalyzes a key control step in prostaglandin biosynthesis. The overall arrangement of the prostaglandin H synthase-1 polypeptide with respect to the endoplasmic reticulum membrane was examined in transiently transfected COS-1 cells, using immunofluorescence microscopy. A bacterial toxin, streptolysin-O, was used for selective plasma membrane permeabilization and a detergent, saponin, for general membrane permeabilization. Treated cells were probed with six antibodies specific for particular prostaglandin H synthase-1 peptide segments and one antibody specific for an inserted viral reporter epitope. Control experiments established that actin, a cytoplasmic marker, was accessible to fluorescein-labeled phalloidin after streptolysin-O treatment, whereas antibodies against protein disulfide isomerase, an endoplasmic reticulum lumenal marker, bound only after saponin treatment, Using this approach to investigate prostaglandin H synthase-1, it was found that streptolysin-O treatment was sufficient to obtain staining of intracellular membranes by antibodies specific for the endogenous C-terminal segment, for the viral reporter inserted at the C-terminus, and for the protease-sensitive region near arg277. In contrast, saponin treatment was necessary for staining by antibodies specific for peptides spanning residues 51-66, 156-170, and 377-390. Antibodies targeted against residues 483-496 did not stain transfected cells even after saponin permeabilization, although they did bind to detergent-solubilized prostaglandin H synthase-1. These results indicate that the C-terminus and arg277 regions of the synthase can be exposed on the cytoplasmic side of the endoplasmic reticulum membrane, whereas regions near N-glycosylation sites are confined to the endoplasmic reticulum lumen and residues 483-496 are inaccessible from either side of the endoplasmic reticulum membrane.

Mechanism of metallothionein gene regulation by heme-hemopexin. Roles of protein kinase C, reactive oxygen species, and cis-acting elements

Heme-hemopexin or cobalt protoporphyrin (CoPP)-hemopexin (a model ligand for hemopexin receptor occupancy) is shown to increase transcription of the metallothionein-1 (MT-1) gene by activation of a signaling pathway. Promoter deletion analysis followed by transient transfection assays show that 110 base pairs (-153 to -43) of 5'-flanking region of the murine MT-1 promoter are sufficient for increasing transcription in response to heme-hemopexin or to CoPP-hemopexin in mouse hepatoma cells. The protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7), prevented the increase in MT-1 transcription by heme-hemopexin, CoPP-hemopexin, or phorbol 12-myristate 13-acetate, but the protein kinase A inhibitor, HA1004, was without effect. N-Acetylcysteine (NAC) and glutathione, as well as superoxide dismutase and catalase, inhibited both the increase in endogenous MT-1 mRNA and the activation of reporter gene activity by heme-hemopexin, CoPP-hemopexin, and phorbol 12-myristate 13-acetate. In sum, these data suggest that reactive oxygen intermediates are generated by heme-hemopexin via events associated with receptor binding, including protein kinase C activation. Induction of heme oxygenase-1 expression, in contrast to MT-1, is significantly less sensitive to NAC. Deletion and mutation analyses of the MT-1 proximal promoter revealed that the sequence 5'-GTGACTATGC-3' (from -98 to -89 base pairs) is, in part, responsible for the hemopexin-mediated regulation of MT-1 which is inhibited by H7. Regulation via this element is also induced by H2O2 showing that it is an antioxidant response element. Heme itself acts via more distal elements on the MT-1 promoter. In contrast to NAC and glutathione, diethyl dithiocarbamate and pyrrolidine dithiocarbamate, which inactivate reactive oxygen intermediates and chelate Zn(II), synergistically augment the induction of MT-1 mRNA levels and reporter gene activity in response to heme-hemopexin via the antioxidant response element by both metal-responsive element-dependent and -independent mechanisms.

[Evaluation of operative corrigent degree of scoliosis by improved Cobb's angle degree of preoperative suspensive roentgenogram]

To achieve best operative result in correction of scoliosis, and avoid complications of the nerve system due to excess correction, we compared the statistical results of modified Cobb's degree of preoperative suspensive roentgenogram and operative corrigent degrees of 331 patients with scoliosis, including 219 with idiopathic scoliosis. The modified Cobb's degrees of the whole group was 20.15 +/- 9.41 in suspension, the operative corrigent degree was 35.34 +/- 13.05, and the operation-suspension difference was 14.62 +/- 11.02. Referring to idiopathic scoliosis, it was 21.79 +/- 8.39, 37.44 +/- 11.82, 15.58 +/- 9.91 respectively. And the statistacal study was performed according to scoliosis type, involved segments, curvature degree, and ages. The parameters were very helpful in the evaluation of currigent effect before operation.

A rifampicin-induced hepatic microsomal enzyme system for the generation of cyclosporine metabolites

A drug-induced rabbit hepatic microsomal enzyme system has been developed to produce milligram quantities of cyclosporine metabolites (CMs). Using a rifampicin-induced microsomal preparation in the presence of a NADPH regenerating system, 60% of the cyclosporine (CsA) was converted to CMs in 2 h. The CMs were recovered by solid phase extraction, and separated by gradient high performance liquid chromatography with two Ultrasphere Ocyl (C8) columns connected in tandem. More than 20 CMs were resolved. The quantities of major CMs produced by 45 mg of microsomal proteins were established by comparing peak areas with known concentrations of authentic CM standards. These major CMs included AM1, AM9, AM19, AM4N, AM1c and the aldehydic isomers (AM1cAL plus AM1AL). Other CMs that were not quantified included AM14N, AM4N9, AM1A, AM1c9, and AM1D1. Several CMs remained to be identified. All CMs were detected by radioimmunoassay using a non-specific CsA antiserum. The purity of the CMs were confirmed by fast atomic bombardment mass spectrometry. Similar findings were observed when erythromycin or trolandomycin was used to induce the hepatic microsomal enzymes. The procedure used to generate CMs was simple. With the enzyme fraction derived from one rabbit liver, 90 to 100 mg of CMs can be obtained. In this study, the metabolite patterns of CsA produced by rabbit liver microsomes were shown to resemble those observed for humans. These results indicate the possibility of using rabbit models to predict CsA biotransformation in man. The CMs generated by this enzyme system can be used to acquire information relevant to the situation in man.

[Study of anti-cerebral thromboembolism injection's activity on experimental arterial thrombosis and its therapeutical mechanism]

Anti-Cerebral Thromboembolism Injection (ACTI), applied intravenously in Cattaneo's animal model of arterial thrombosis, could significantly reduce the weight of thrombus, blood viscosities, plasma TXB2 level and delay the prothrombin time, compared to control group (P < 0.05). From this trial, it was indicated that ACTI's reducing thrombosis action was the result of inhibiting aggregation and releasing of platelets through reducing whole blood viscosities and TXB2 level.

[Effects of 3 kinds of decoction on serum gastrin, gastrin cell density and the content of PGE2 of gastric antral mucosa in experimental chronic gastritis in rats]

Experimental chronic gastritis (ECG) models were established in rats by inserting a spring into pyloric canal as well as feeding sodium deoxycholate. An experiment was undertaken to observe the therapeutic effects of three formulas of traditional Chinese medicine "Shipitong" (SPT), "Ganpingyangwei" (GPYW) and "Weile" (WL). The experimental results show that all of the three decoctions can make serum gastrin, gastrin cell density and amount of antral mucosal PGE2 of the ECG rats return to normal levels.

CD36 gene transfer confers capacity for phagocytosis of cells undergoing apoptosis

Phagocyte recognition and ingestion of intact cells undergoing apoptosis are key events in this generally important program of cell death. Insufficient phagocyte capacity for apoptotic cells can result in failure to clear dying cells before membrane integrity is lost, resulting in leakage of noxious cell contents and severe tissue damage. However, no means has been available to increase phagocytic clearance of apoptotic cells. We now report that transfection of the macrophage adhesion molecule CD36 into human Bowes melanoma cells specifically conferred greatly increased capacity to ingest apoptotic neutrophils, lymphocytes, and fibroblasts, comparable to that exhibited by macrophages. Furthermore, when CD36 was transfected into another cell type with limited capacity to take up apoptotic bodies, the monkey COS-7 cell, similar effects were observed. Therefore, CD36 gene transfer can confer "professional" capacity to ingest apoptotic cells upon "amateur" phagocytes.

[An experimental study on the integrated effects of heat-cleaning and detoxifying drugs and fire-purging drugs used in combination]

Heat-cleaning and detoxifying drugs and fire-purging drugs used in combination have been proved able to restore the endotoxin-induced deviant of HCT, blood viscositites, PTT and fibrinolytic activity, and reduce the blood content of both endotoxin and PGE2 in rabbits. In addition, the combination can also decrease the pes swelling percentage in rats as well as evans blue extravasation volume in mice. In practice, however, it should be noted that the bitter and cold qualities of these two kinds of drugs may be harmful to health.

The orphan receptor hepatic nuclear factor 4 functions as a transcriptional activator for tissue-specific and hypoxia-specific erythropoietin gene expression and is antagonized by EAR3/COUP-TF1

The erythropoietin (Epo) gene is regulated by hypoxia-inducible cis-acting elements in the promoter and in a 3' enhancer, both of which contain consensus hexanucleotide hormone receptor response elements which are important for function. A group of 11 orphan nuclear receptors, transcribed and translated in vitro, were screened by the electrophoretic mobility shift assay. Of these, hepatic nuclear factor 4 (HNF-4), TR2-11, ROR alpha 1, and EAR3/COUP-TF1 bound specifically to the response elements in the Epo promoter and enhancer and, except for ROR alpha 1, formed DNA-protein complexes that had mobilities similar to those observed in nuclear extracts of the Epo-producing cell line Hep3B. Moreover, both anti-HNF-4 and anti-COUP antibodies were able to supershift complexes in Hep3B nuclear extracts. Like Epo, HNF-4 is expressed in kidney, liver, and Hep3B cells but not in HeLa cells. Transfection of a plasmid expressing HNF-4 into HeLa cells enabled an eightfold increase in the hypoxic induction of a luciferase reporter construct which contains the minimal Epo enhancer and Epo promoter, provided that the nuclear hormone receptor consensus DNA elements in both the promoter and the enhancer were intact. The augmentation by HNF-4 in HeLa cells could be abrogated by cotransfection with HNF-4 delta C, which retains the DNA binding domain of HNF-4 but lacks the C-terminal activation domain. Moreover, the hypoxia-induced expression of the endogenous Epo gene was significantly inhibited in Hep3B cells stably transfected with HNF-4 delta C. On the other hand, cotransfection of EAR3/COUP-TF1 and the Epo reporter either with HNF-4 into HeLa cells or alone into Hep3B cells suppressed the hypoxia induction of the Epo reporter. These electrophoretic mobility shift assay and functional experiments indicate that HNF-4 plays a critical positive role in the tissue-specific and hypoxia-inducible expression of the Epo gene, whereas the COUP family has a negative modulatory role.

Proinflammatory cytokines potentiate thrombospondin-mediated phagocytosis of neutrophils undergoing apoptosis

Apoptosis leads to swift recognition, ingestion, and degradation of intact senescent neutrophils by macrophages. This protects tissues from leakage of noxious contents from dying cells and may promote resolution of inflammation. However, little has been known of the mechanisms that regulate macrophage capacity for apoptotic cells during an inflammatory response. We examined whether proinflammatory cytokines modulated phagocytosis of senescent neutrophils undergoing apoptosis by human monocyte-derived macrophages at 4 days maturity (4d M phi), an in vitro model of neutrophil "disposal" by apoptosis. Pretreatment of 4d M phi with granulocyte-macrophage-CSF increased the proportion of 4d M phi taking up apoptotic PMN in a concentration-dependent fashion by up to approximately 240%. This was by a rapid effect detectable by 4 h and exerted on the M phi, not the PMN. Granulocyte-macrophage-CSF also increased the number of apoptotic PMN taken up by each M phi. IFN-gamma, IL-1 beta, TNF-alpha, and TGF-beta 1 also enhanced phagocytosis, but IL-4 and IL-6 had no effect. In each case, the cytokine-expanded phagocytic subpopulation employed the thrombospondin (TSP)-dependent recognition mechanism defined for mature M phi, in which M phi vitronectin receptor and CD36 cooperate. However, commensurate increases in M phi expression of VnR, TSP, or CD36 were not detectable, indicating that TSP-mediated recognition can be recruited by other mechanisms. Cytokines did not recruit phosphatidylserine-dependent recognition, the other major mechanism by which some macrophage populations ingest apoptotic cells. Thus, M phi phagocytosis of apoptotic neutrophils can be potentiated by proinflammatory cytokines, suggesting a mechanism for negative feedback control of neutrophil number at inflamed sites.

Proinflammatory cytokines potentiate thrombospondin-mediated phagocytosis of neutrophils undergoing apoptosis

Apoptosis leads to swift recognition, ingestion, and degradation of intact senescent neutrophils by macrophages. This protects tissues from leakage of noxious contents from dying cells and may promote resolution of inflammation. However, little has been known of the mechanisms that regulate macrophage capacity for apoptotic cells during an inflammatory response. We examined whether proinflammatory cytokines modulated phagocytosis of senescent neutrophils undergoing apoptosis by human monocyte-derived macrophages at 4 days maturity (4d M phi), an in vitro model of neutrophil "disposal" by apoptosis. Pretreatment of 4d M phi with granulocyte-macrophage-CSF increased the proportion of 4d M phi taking up apoptotic PMN in a concentration-dependent fashion by up to approximately 240%. This was by a rapid effect detectable by 4 h and exerted on the M phi, not the PMN. Granulocyte-macrophage-CSF also increased the number of apoptotic PMN taken up by each M phi. IFN-gamma, IL-1 beta, TNF-alpha, and TGF-beta 1 also enhanced phagocytosis, but IL-4 and IL-6 had no effect. In each case, the cytokine-expanded phagocytic subpopulation employed the thrombospondin (TSP)-dependent recognition mechanism defined for mature M phi, in which M phi vitronectin receptor and CD36 cooperate. However, commensurate increases in M phi expression of VnR, TSP, or CD36 were not detectable, indicating that TSP-mediated recognition can be recruited by other mechanisms. Cytokines did not recruit phosphatidylserine-dependent recognition, the other major mechanism by which some macrophage populations ingest apoptotic cells. Thus, M phi phagocytosis of apoptotic neutrophils can be potentiated by proinflammatory cytokines, suggesting a mechanism for negative feedback control of neutrophil number at inflamed sites.

[The effects of progestin on the bone metabolism in postmenopausal women]

Thirty postmenopausal women, including 26 with history of hysterectomy and bilateral salpingooophorectomy due to uterine myoma and 4 with natural menopause without any diseases were randomly allocated into two groups. Fifteen subjects received medroxyprogesterone acetate (MPA) 10 mg twice daily for three months, the other 15 received both MPA 10 mg twice daily and cyclopentylethinyl estriol (CEE3) 5 mg once a month for three months. Fasting urinary calcium/creatinine (Ca/Cr) and hydroxyproline/creatinine (OHpr/Cr) ratio, serum calcitonon (CT) and alkaline phosphatase (AKP) concentrations were measured before and after treatment in all subjects. The results showed that in both groups, the fasting urinary Ca/Cr and OHpr/Cr ratio reduced significantly, while serum CT and AKP increased significantly after treatment. The changes of these parameters were not significantly different between these two groups. These data indicated that progestin alone appeared effective in preventing postmenopausal osteoporosis.

Prostaglandin H synthase-1: evaluation of C-terminus function

The first committed step in prostaglandin biosynthesis is catalyzed by prostaglandin H synthase, an enzyme localized to the endoplasmic reticulum (ER) membrane in a variety of cells. Several types of C-terminal region peptide sequence motifs have been found to lead to ER retention of other proteins. We have tested the potential role for such signals in the ER localization and catalytic activity of human isoform-1 of the synthase (PGHS-1). PGHS-1 mutants with alterations in the C-terminus designed to disrupt potential retention signals were expressed in transfected COS-1 cells. The mutations included: substitution of valine for the ultimate leucine residue (position 600) to disrupt a KDEL-type signal, substitution of a neutral glutamine for arginine at position 595 to disrupt signals based on positive charge, and deletion of the last six residues, to remove all of the wild-type extreme C-terminus. The subcellular localization of each recombinant PGHS-1 was assessed by differential centrifugation and by immunofluorescence microscopy. None of the mutations led to a significant change in the distribution of PGHS-1 between microsomes and other cellular fractions. Immunostaining of wild-type PGHS-1 and all of the mutants colocalized with that of protein disulfide isomerase, an ER marker protein. However, mutation of the terminal leucine or deletion of the last six residues did lead to loss of cyclooxygenase activity. Mutation of the terminal leucine also altered the pattern of fragments produced by limited proteolysis, indicating that this mutation led to changes in the polypeptide folding which might account for the loss of activity. The results indicate that the extreme C-terminal region is important to the functional integrity of PGHS-1, but it is not an essential part of the intracellular targeting mechanism.

[Experimental study on compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs]

The article describes the effectiveness of compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs to the animal model with endotoxemia and nonspecific inflammation. The compatible application reduces PGE2, endotoxin blood concentration and reduced viscosity of whole blood, decreases Evans blue extravasation volume and pes swelling percentage, increases serum cortisol content and enhances fibrinolytic activity. The experimental result shows that in most cases these two drugs work better when used in combination which implies that compatible application is more effective in detoxification, antiinflammation and inflammation recovery.

Epidural versus subcutaneous administration of alfentanil for the management of postoperative pain

This study was designed to compare the efficacy and serum concentrations of alfentanil given subcutaneously (SQ) or epidurally (EPID) for treatment of postoperative pain. Following abdominal surgery, patients (n = 12) were randomly assigned to receive double-blind SQ or EPID alfentanil over 24 h via the allocated route (1 mg along with 0.2 mg/h and 0.2-mg boluses on demand) and saline via the other route of administration using a patient-controlled analgesic (PCA) delivery system. Significantly less EPID alfentanil produced better quality analgesia and fewer side effects than SQ alfentanil. The fact that EPID analgesia was maintained with serum alfentanil concentrations less than those producing systemic analgesia confirms the spinal site of the EPID alfentanil action.

Overexpression and characterization of recombinant human fusion protein IL-6/IL-2 (CH925)

An expression vector encoding the human recombinant fusion protein interleukin 6/interleukin 2 (IL-6/IL-2) was constructed. When a flexible linker had been synthesized and ligated with the IL-2 gene fragment by polymerase chain reaction (PCR) amplification, the IL-6 gene fragment was unidirectionally inserted into the upstream of the linker-IL-2 sequence. The molecule of the IL-6-linker-IL-2 fusion gene named E. coli DH5 alpha/pfIL-6/2 was cloned and identified by DNA sequencing. The expressed protein named as CH925 showed a strong band on SDS-PAGE and amounted to 32% of total cell protein, and its estimated molecular weight was about 37 kDa. The fusion protein purified by gel filtration and reversed-phase HPLC showed as almost homogeneous. CH925 possesses both IL-2 and IL-6 activities when assayed by CTLL2- and 7TD1-dependent cell lines, respectively. The specific activity of IL-2 was 2.1 x 10(6) U/mg while that of IL-6 was 2.3 x 10(8) U/mg. Our studies exhibited that CH925 exerted a significant augmentative effect on the growth of erythroid colony forming units (CFU-E), and synergized with erythropoietin (EPO) and/or IL-3 in a dose-dependent way. Our experimental results also showed CH925 at a low dose causing active lymphokine-activated killer (LAK) cell proliferation more vigorous than IL-2 and/or IL-6 (p < 0.001). CH925 is a novel fusion protein, being neither IL-6 nor IL-2, more potent than IL-2 and/or IL-6 and causing non-IL-2 and non-IL-6 functions of strong EPO-like and mild IL-3-like effects on erythroid progenitor cell growth. There is a potential for efficacious clinical application of CH925.

Glomerular prostaglandins modulate vascular reactivity of the downstream efferent arterioles

The balance of vascular resistance in afferent (Af-) and efferent arterioles (Ef-Arts) is a crucial factor that determines glomerular hemodynamics. We have recently reported that when Ef-Arts were perfused from the distal end of the Af-Art through the glomerulus (orthograde perfusion; OP), both angiotensin II (Ang II) and norepinephrine (NE) induced much weaker constriction than they did when Ef-Arts were perfused from the distal end (retrograde perfusion; RP). This difference was not affected by inhibiting synthesis of nitric oxide. In the present study, we tested the hypothesis that glomerular prostaglandins (PGs) may modulate vascular reactivity of the downstream Ef-Art. In addition, we examined the possible modulatory role of PGs in the Af-Art responses to Ang II or NE. Both Ang II and NE caused dose-dependent constriction of Ef-Arts with either OP or RP; however, the constriction was stronger in RP. At 10(-8) M, Ang II decreased Ef-Art diameter by 35 +/- 3.5% in OP (N = 9) compared to 73 +/- 3.9% in RP (N = 5), while 10(-6) M NE decreased the diameter by 25 +/- 3.6% in OP (N = 9) compared to 62 +/- 7.2% in RP (N = 5). Pretreatment with 5 x 10(-5) M indomethacin (Indo) did not alter basal diameter with either method of perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Dielectric properties of human red blood cells in suspension at radio frequencies

Dielectric properties of human red blood cells (RBCs) in suspension (hematocrit 50%) from 243 healthy persons (120 males, 123 females) were measured at 25 degrees C in a frequency range of 1-500 MHz, with a coaxial transmission line reflection method (one-side measurement). The measuring system, controlled by an IBM-PC computer, was composed of a network analyzer (HP4195A), an impedance test adapter (HP41951-61001), a coaxial line sensor, and a temperature-controlling set. The data measured revealed a statistically significant age dependence, with a critical age of about 49 years, above which permittivity and conductivity of human RBCs in suspension decreased significantly.

Evidence for the role of nitric oxide in macula densa control of glomerular hemodynamics

There is evidence that nitric oxide, an endothelium-derived relaxing factor, may be produced by the macula densa, as well as by blood vessels, within the kidney. To examine the role of nitric oxide in macula densa control of glomerular hemodynamics directly, we performed in vitro microperfusions of both rabbit afferent arterioles (with the glomerulus intact) and adherent tubular segments consisting of portions of the thick ascending limb, macula densa, and early distal tubule. While keeping afferent arteriolar pressure constant at 60 mmHg, we examined the effect of Nw-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis, added to a macula densa perfusate. When the macula densa perfusate was changed from low to high NaCl, the diameter of the arterioles decreased from 16.3 +/- 1.0 to 14.0 +/- 1.1 microns (n = 10; P < 0.001). Addition of 10(-5) M L-NAME to the high NaCl solution further decreased the diameter to 11.9 +/- 1.1 microns (P < 0.001). In contrast, when macula densa perfusion was maintained with the low NaCl solution, addition of L-NAME had no effect. L-NAME-induced constriction was completely reversed by adding 10(-3) M L-arginine (the precursor of nitric oxide) but not D-arginine (an inactive isomer) to the macula densa perfusate. We confirmed that perfusing the macula densa with L-NAME did not affect the vasodilator action of acetylcholine added to the lumen of the afferent arteriole, indicating that NO synthesis by the arteriole was not altered. Thus, our findings suggest that the macula densa may produce nitric oxide, which in turn modulates the afferent arteriolar constriction induced by high concentrations of NaCl at the macula densa.

Glomerular mesangial cells and inflammatory macrophages ingest neutrophils undergoing apoptosis

Apoptosis or programmed cell death of senescent neutrophils leading to their uptake by phagocytes is a general mechanism by which neutrophils may be removed from inflamed sites in vivo, promoting resolution rather than persistence of inflammation. We now report morphological evidence of neutrophil apoptosis leading to uptake by glomerular cells in rats with experimental glomerulonephritis. In addition to confirming that inflammatory macrophages take up apoptotic neutrophils, these studies indicated that glomerular mesangial cells can also participate in this mode of neutrophil clearance. Furthermore, human neutrophils which had been "aged" in vitro so as to undergo apoptosis were ingested by 31.5 +/- 1.3% (mean +/- SE) of cultured human mesangial cells, but there was minimal recognition of freshly isolated neutrophils (2.2 +/- 0.1%). Centrifugal elutriation of aged neutrophil populations yielded fractions with varying degrees of apoptosis (from 11.1 to 79.4%). Uptake of these fractions (by 8.2% to 59.8% of mesangial cells) was closely correlated with apoptosis (r = 0.96, P less than 0.0001). This demonstrated that recognition was dependent upon apoptosis, as in previous reports of macrophage recognition of aged neutrophils. However, by contrast, a partial requirement for serum was observed. These data indicate a hitherto unexpected function for the mesangial cell in clearance of senescent neutrophils from the glomerulus which may supplement inflammatory macrophage uptake of leucocytes undergoing apoptosis.

Thrombospondin cooperates with CD36 and the vitronectin receptor in macrophage recognition of neutrophils undergoing apoptosis

We have investigated the cell surface recognition mechanisms used by human monocyte-derived macrophages (M phi) in phagocytosis of intact aging human neutrophils (PMNs) undergoing apoptosis. This study shows that the adhesive protein thrombospondin (TSP) was present in the interaction, both associated with the M phi surface and in solution at a mean concentration of 0.59 micrograms/ml. The interaction was inhibited by treatment of M phi (but not aged PMN) with cycloheximide, but could be "rescued" by replenishment with exogenous TSP. Under control conditions, M phi recognition of aged PMNs was specifically potentiated by purified platelet TSP at 5 micrograms/ml, present either in the interaction or if preincubated with either cell type, suggesting that TSP might act as a "molecular bridge" between the two cell types. In support, both aged PMN and M phi were found to adhere to TSP, and phagocytosis of aged PMN was specifically inhibited by (a) excess soluble TSP; (b) antibodies to TSP that also inhibit TSP-mediated adhesion to aged PMN; and (c) down-regulation of M phi receptors for TSP by plating M phi on TSP-coated surfaces. Furthermore, inhibition with mAbs/Arg-Gly-Asp-Ser peptide of the candidate M phi receptors for TSP, CD36, and alpha v beta 3 exerted synergistic effects on both M phi recognition of aged PMN and M phi adhesion to TSP, indicating that "two point" adhesion of TSP to these M phi structures is involved in phagocytosis of aged PMN. Our findings indicate newly defined roles for TSP and CD36 in phagocytic clearance of senescent neutrophils, which may limit inflammatory tissue injury and promote resolution.

The cell recognition molecule, cognin, mediates choline acetyltransferase activity in embryonic chick retina

Cell signaling and cell-cell interactions play an important role in neuronal differentiation in the embryonic CNS. Previous work (Hausman, R.E., Vivek Sagar, G.D. and Shah, B.H., Dev. Brain Res., 59 (1991) 31-37) had shown that cholinergic differentiation in the embryonic chick retina depends on insulin and neuron-neuron interactions. Here, we pursued the molecular nature of that dependence on cell interactions. The embryonic chick retina is known to contain several cell adhesion or recognition molecules. We asked if retina cognin, a 50 kDa cell surface-associated protein, played a role in controlling cholinergic differentiation in the developing chick retina. As previously, cholinergic differentiation was measured by two markers: choline acetyltransferase (ChAT) activity and high-affinity choline uptake. We used polyclonal antibody to cognin to determine if blocking cognin-mediated cell interactions would affect the normal embryonic increases in these cholinergic markers. We demonstrated a 40% inhibition of the normal developmental appearance of ChAT activity in retina neuronal cultures from early development, but no effect in cultures from more differentiated retina. The inhibition was selective for retina, since it was not seen in neural tissues like cerebrum and cerebellum that also express ChAT. In contrast to the effect of insulin, choline uptake was not affected by treatment with cognin antibody. Antibodies to two other cell recognition molecules present in the retina (Ng-CAM and N-cadherin) did not block the normal developmental appearance of ChAT. These results suggest that cognin-mediated interactions play a unique role in the control of one aspect of cholinergic differentiation in the developing chick retina.

[Compatibility of Chinese drugs radix Aconiti carmichaeli with rhizoma Pinelliae]

To find out whether the Chinese drug Radix Aconiti Carmichaeli is compatible with another Chinese drug Rhizoma Pinelliae in preparation, the two medicinal herbs were made into different forms of decoctions. Experiments with these decoctions were carried out to observe the action on isolated hearts of toads and the ECG and acute toxicity on mice. The results showed that in terms of toxicity there was no marked increase in the mixed decoction as compared with the other two decoctions prepared from Radix Aconiti Carmichaeli and Rhizoma Pinelliae separately.

[Spermine inhibition of in vitro fertilizing ability of human spermatozoa and its possible mode of action]

The direct effect of spermine at various concentrations (0.25-8.0 mmol/L) on in vitro fertilizing ability of human spermatozoa was evaluated by the penetration test of zona-free hamster egg. To study the effect of spermine on capacitation, as judged by the rate of penetration, spermatozoa were incubated in BWW with various concentrations of spermine for 6 h at 37 degrees C. The hyperactivated motility of spermatozoa was markedly inhibited by spermine at a concentration of 4.0 mmol/L. The penetration rate was decreased proportionally to the dose of spermine used. Spermatozoa were incubated in BWW with 0.5 mmol/L spermine for 6 h and another 4 h after spermine was washed off with spermine-free BWW. The percentage of penetration was comparable to that of the control. Therefore, spermine-mediated inhibition of capacitation was reversible. Moreover, exogenous dbcAMP (0.5-1.0 mmol/L) or caffeine (10 mmol/L) could antagonize significantly the spermine-induced inhibition of capacitation with a correlation coefficient of 0.990. The content of spermine in fertile men spermatozoa was assayed by HPLC. Before capacitation spermine in spermatozoa was 7.05 micrograms/10(7) cells, whereas after capacitation it was no longer detectable, indicating that spermine may be an inhibitor of in vitro capacitation in human sperm. To study the effect of spermine on capacitated sperm, spermine was added to the BWW medium after sperm had been preincubated in spermine-free BWW. The persistent presence of spermine could interfere with spermatozoa attachment to, binding to and penetration into zona-free hamster eggs, which was related to the concentration (r = 0.820) used.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin H synthase: spectroscopic studies of the interaction with hydroperoxides and with indomethacin

Prostaglandin H synthase has both a heme-dependent peroxidase activity and a cyclooxygenase activity. A current hypothesis considers the cyclooxygenase reaction to be a free radical chain reaction, initiated by an interaction of the synthase peroxidase with hydroperoxides leading to the production of a tyrosyl free radical [Stubbe, J. A. (1989) Annu. Rev. Biochem. 58, 257-285]. We have examined the kinetics of radical formation with both ethyl hydroperoxide (EtOOH) and 15-hydroperoxyeicosatetraenoic acid (15-HPETE) and have analyzed the effects of indomethacin (a selective cyclooxygenase inhibitor) and tetranitromethane (TNM; a selective agent for nitration of tyrosyl residues) on the synthase. At -14 degrees C both EtOOH and 15-HPETE generated within 5 s a free radical species whose electron paramagnetic resonance spectrum was dominated by a doublet centered at g = 2.005 (splitting of approximately 16 G; overall peak-to-trough width of 35 G) that has been attributed to tyrosyl radical. The doublet subsequently gave way to a singlet with a similar peak-to-trough width; the doublet-to-singlet transition was complete in 20-60 s. The intensity of the doublet/singlet combination peaked at 0.6 spins/heme after 120 s with EtOOH and at about 0.3 spins/heme after 20 s with 15-HPETE; the radical intensity declined slowly with EtOOH but more rapidly with 15-HPETE. Reaction of the indomethacin-synthase complex with EtOOH resulted in a narrower (peak-to-trough width of 24 G) singlet free radical signal, with no evidence of an earlier doublet; the intensity of the singlet peaked at 0.45 spins/heme after about 300 s. Reaction of TNM-treated synthase with EtOOH resulted in a singlet almost identical with that seen for the indomethacin-synthase complex. Reaction of the synthase holoenzyme with TNM at pH 8.0 led to inactivation of both cyclooxygenase and peroxidase activity, with the former being lost rapidly and completely while the latter was lost slowly and to about 50%. Ibuprofen, a competitive cyclooxygenase inhibitor, slowed the rate of inactivation of the cyclooxygenase by about 20-fold. The rate of inactivation of the cyclooxygenase activity in synthase apoenzyme by TNM was also about 20-fold less than that observed with the holoenzyme. Amino acid analyses revealed that TNM-reacted holoenzyme with less than 10% residual activity contained 1.8 nitrotyrosines/subunit; apoenzyme reacted under the same conditions had greater than 80% of the original activity and contained 0.7 nitrotyrosine/subunit.(ABSTRACT TRUNCATED AT 400 WORDS)