Influence of neutralizing antibodies to adalimumab and infliximab on the treatment of psoriasis

BACKGROUND

Current treatment with biologics has produced dramatic therapeutic effects in patients with psoriasis, although these agents occasionally decrease in efficacy. One of the main factors responsible for this attenuation is attributed to the development of antidrug antibodies (ADAs).

OBJECTIVES

To analyse the relationship between serum drug concentrations, the presence of ADAs and treatment efficacy of adalimumab and infliximab, and to determine the optimal use of these biologics.

METHODS

This was a 1-year prospective study in the dermatology departments of Kobe University Hospital and collaborating hospitals. All patients starting a regimen of adalimumab and infliximab for psoriasis were included. We measured the serum concentration of the drugs and titres of antibodies to adalimumab and infliximab, as well as the Psoriasis Area and Severity Index scores at weeks 0, 4, 12, 24 and 48 during the first year of treatment.

RESULTS

We observed a 50% positive rate of ADAs to adalimumab, and a 41% positive rate of ADAs to infliximab. The titres of ADAs showed a wide range from low to high titres. In the high-titre groups, the patients exhibited a decreased clinical response, and demonstrated a negative correlation between titre and clinical response. However, an equivalent therapeutic effect was observed between the low-titre group and the group with no antibodies detected for adalimumab. For infliximab, the patients with ADAs showed decreased clinical response. An apparent negative correlation between antibody production and reduced clinical response was observed.

CONCLUSIONS

Two biologics, adalimumab and infliximab, showed different therapeutic behaviour. The measurement of ADAs and drug concentrations has important implications for treatment with biologics.

Regulation of RalA GTPase by phosphatidylinositol 3-kinase as visualized by FRET probes

Small GTPases, which are binary switches regulating various signal transduction cascades, function not only to relay signals but also to integrate them from multiple signalling branches. For example, RalA activity is regulated by at least three signalling cascades involving Ras, Rac or PI3K (phosphoinositide 3-kinase). To untangle such complicated regulatory mechanisms, we have been developing probes for GTPases, kinases and phosphatidylinositols based on the principle of FRET (fluorescence resonance energy transfer). We demonstrated previously that, upon EGF (epidermal growth factor) stimulation, Ras activity increases diffusely in the plasma membrane, whereas RalA activity increases predominantly in lamellipodial protrusions. Here, we show that the level of PtdIns(3,4,5)P3 is increased diffusely in the plasma membrane, whereas, in the central region, the level of PtdIns(3,4)P2 is increased more in the nascent lamellipodia than in the plasma membrane. The distribution and time course of Akt activation are similar to those of increased PtdIns(3,4)P2 levels. These observations suggest that the increase in PtdIns(3,4)P2 and the subsequent activation of Akt may be responsible for the localized activation of RalA. Thus the signals from Ras and PI3K converge at the level of Ral GEFs (guanine nucleotide-exchange factors), and this convergence restricts the area of RalA activation.

Cross-clade neutralizing antibody production against human immunodeficiency virus type 1 clade E and B' strains by recombinant Mycobacterium bovis BCG-based candidate vaccine

The recombinant Mycobacterium bovis BCG (rBCG) vector-based vaccine secreting the V3 principal neutralizing epitope of human immunodeficiency virus type 1 (HIV-1) Japanese strain was reported to induce both humoral and cellular immune responses effectively [Proc. Natl. Acad. Sci. USA. 92 (1995) 10693]. The antigen-secreting rBCG system was applied to the V3 epitope of clade E HIV-1 in this study. The V3 sequence of 19 amino acids (aa) and 15aa fused with mycobacterial alpha-antigen was not secreted while 12aa and 11aa sequences were successfully secreted from BCG cells. Serum IgG from guinea pig which was immunized with 12aa epitope-secreting recombinant BCG neutralized the WHO reference strain as well as primary field isolates of clade E virus. The serum IgG could also neutralize Thai B (clade B') strains which possessed a conserved GPGQ motif in their V3 sequences. These data suggest that the rBCG construct secreting the 12aa epitope is implicated in the development of a prophylactic vaccine in Thailand in which both clade E and B' viruses are prevalent.

Evidence of primary beta-cell destruction by T-cells and beta-cell differentiation from pancreatic ductal cells in diabetes associated with active autoimmune chronic pancreatitis

OBJECTIVE

Diabetes associated with autoimmune chronic pancreatitis (ACP) is a subtype of diabetes that is responsive to corticosteroid treatment of progressive endocrine and exocrine dysfunction. However, little is known about pathological changes of islet and exocrine pancreas in ACP.

RESEARCH DESIGN AND METHODS

We examined pancreatic specimens obtained on biopsy from four diabetic men with ACP (mean [range]: age 62 years [48-78], duration of ACP 3 months [1-5], duration of diabetes 1 month [0-3]) morphologically, immunohistochemically, and morphometrically.

RESULTS

The pancreatic specimens in all cases exhibited inflammatory cell infiltration surrounding ductal cells and extensive fibrosis. Some islets were infiltrated with mononuclear cells with disrupted beta-cells. The subsets of T-cells infiltrated to the islets were mainly CD8(+). Islet beta-cell volume was decreased; the mean percentage area of beta-cells in the islets in four cases with ACP were 16% (range 13-20) (P = 0.0015 vs. type 2 diabetic patients, 48% [27-73], n = 8; P = 0.0002 vs. nondiabetic control subjects, 58% [39-77], n = 7). Preserved ductal cells were surrounded predominantly by CD8(+) or CD4(+) T-cells. Some cytokeratin 19-positive ductal cells contained insulin and glucagon, representing upregulated differentiation of islet cells from ductal cells. Insulin promoter factor-1 (IPF-1) was hyperexpressed in insulin-containing ductal cells.

CONCLUSIONS

Diabetes associated with ACP is caused by T-cell-mediated mechanisms primarily involving islet beta-cells as well as pancreatic ductal cells. In ACP, ductal islet precursor cells were associated with IPF-1 hyperexpression, suggesting a critical role of IPF-1 on islet cell differentiation and eventual beta-cell restoration.

Collaborative study on rat sperm motion analysis using CellSoft Series 4000 semen analyzer

A collaborative study was conducted to determine useful and sensitive rat sperm motion parameters in a CellSoft Series 4000 semen analyzer to detect the effects of compounds on sperm motion. The effects on the sperm motion parameters were investigated using alpha-chlorohydrin, boric acid, ethinylestradiol, ethyl methanesulfonate, nitrazepam, nitrobenzene, ornidazole, sulfasalazine or valproic acid which are well known to induce reproductive or testicular toxicities. All compounds used in this study decreased percentage of motile sperm (% motile). Curvilinear velocity (VCL), maximum and mean amplitude of lateral head displacement (ALH max and ALH mean) were decreased by treatment with all compounds except for valproic acid. Treatment with alpha-chlorohydrin, ornidazole or sulfasalazine under mid-dosage regimens decreased only these parameters. Beat cross frequency (BCF) was increased by treatment with sulfasalazine. There were some treatments which caused either decreased or increased changes irrespective of dosage regimen in linearity, average radius, percentage of circular-swimming sperm out of motile sperm (circular/motile) and percentage of circular-swimming sperm out of all sperm (circular/all). Based on these results, we concluded that % motile, VCL, ALH max and ALH mean are considered useful and sensitive parameters for evaluating the effects of compounds on sperm motion. A parameter of BCF can be useful to detect the effects of specific compounds on sperm motion. Linearity, average radius, circular/motile and circular/all are not considered useful or sensitive indicators to detect the effects of compounds on sperm motion.

Significance of Asn-77 and Trp-78 in the catalytic function of undecaprenyl diphosphate synthase of Micrococcus luteus B-P 26

The primary structures of cis-prenyltransferases are completely different from those of trans-prenyltransferases. To obtain information about amino acid residues relating to catalytic function, random mutation of the undecaprenyl diphosphate synthase gene of Micrococcus luteus B-P 26 was carried out to construct a mutated gene library using an error-prone polymerase chain reaction. From the library, the mutants showing poor enzymatic activity were selected by the colony autoradiography method. Among 31 negative clones selected from 3,000 mutants, two clones were found to contain only one amino acid substitution at either Asn-77 or Trp-78. To determine the functional roles of these interesting residues, we prepared six mutated enzymes with substitutions at residues Asn-77 or Trp-78 by site-directed mutagenesis. Substitution of Asn-77 with Ala, Asp, or Gln resulted in a dramatic decrease in catalytic activity, but the K(m) values for both allylic and homoallylic substrates of these mutant enzymes were comparable to those of the wild-type. On the other hand, three Trp-78 mutants, W78I, W78R, and W78D, showed 5-20-fold increased K(m) values for farnesyl diphosphate but not for Z-geranylgeranyl diphosphate. However, these mutants showed moderate levels of enzymatic activity and comparable K(m) values for isopentenyl diphosphate to that of the wild-type. These results suggest that the Asn-Trp motif is involved in the binding of farnesyl diphosphate and enzymatic catalysis.

Availability of sperm examination for male reproductive toxicities in rats treated with boric acid

Sperm morphological examination, computer-assisted sperm analysis (CASA) and histopathologic examination of the testis and epididymis were performed for male rats treated orally with boric acid for 3 weeks at dosage levels of 50, 150 and 500 mg/kg/day, and treated males were mated with untreated females. None of the males treated with 500 mg/kg/day could impregnate untreated females. The fertility index showed a tendency to decrease in males treated with 150 mg/kg/day. At necropsy, the pre-implantation loss rate in females mated with males treated with 150 mg/kg/day was higher than the control values. Upon epididymal sperm analysis using the CASA system, all parameters including the number of sperm and sperm motions were found to be affected in males treated with 500 mg/kg/day, and the number of sperm, percent motile, velocities and amplitude of lateral head displacement (ALH) were affected in males treated with 150 mg/kg/day. Upon sperm morphological examination, head and tail abnormalities were observed in males treated with 150 and 500 mg/kg/day. In the histopathological examination, atrophy of the seminiferous tubules and multinucleated giant cells in the testes were observed in males treated with 500 mg/kg/day.

Effect of posture change on control of ventilation

To clarify the control mechanism of ventilation during posture change, ventilatory parameters, PETCO2, and ventilatory response to CO2 were examined in 11 healthy male subjects at supine (0 degrees) and 75 degrees head-up tilt positions. Minute expiratory ventilation (V.E), tidal volume (VT), respiratory frequency (f), end-tidal and transcutaneous PCO2 and CO2 output (V.CO2), and ventilatory response to CO2 were measured during a steady state condition. V.E (V.A) and VT increased significantly at 75 degrees tilt with significant decrease in PETCO2 from 40.1 mmHg (0 degrees) to about 36.1 mmHg (75 degrees). Transcutaneous PCO2 also decreased during tilt, by 3.3 mmHg. Physiological dead space (VD/VT) and V.CO2, however, remained unchanged, and ventilatory equivalent (V.E/V.CO2, V.A/V.CO2) increased significantly. The CO2-ventilatory response curve shifted upward (or leftward) without significant change in the response slope. At 75 degrees tilt, EMG activity of gastro-cnemius muscle increased. These findings suggested that PETCO2 decreased because of increased V.E (V.A) with a leftward shift of CO2-ventilatory response curve. Various signals such as afferents from lower extremities might have net stimulatory effects on a CO2-ventilation control system to reset the controlled level of PETCO2 to a lower range, but without significant change in CO2-ventilatory response during upright position.

Importance of sialic acid in recombinant thrombomodulin in terms of pharmacokinetics and separation of desialyzed glycoprotein

Recombinant glycosaminoglycan-modified urinary thrombomodulin (GAG-UTM) expressed in mouse C-127 cells has potent antithrombotic activity available as an anticoagulant. GAG-UTM, a glycoprotein with sialic acid, was investigated regarding the influence of the terminal sialic acid on its pharmacokinetics upon rapid intravenous injection in rat. Asialo GAG-UTM desialated by neuraminidase was cleared rapidly from plasma. Sialyzed GAG-UTM, a sialyzed asialo GAG-UTM with alpha-2, 6-sialyltransferase, containing sialic acid similarly to native sialo GAG-UTM, had only a short half-life in plasma, suggesting that the binding site of sialic acid on galactose was not only sialyzed with alpha-2, 6-sialyltransferase but also with 2, 3-sialyltransferase. Asialo GAG-UTM with oxidized terminal galactose, however, had a long half-life. These results suggest that terminal sialic acid may be important to the pharmacokinetics of GAG-UTM; therefore, an analysis of asialo GAG-UTM became significant for quality control. In order to analyze sialo- and asialo-types in the early stage of purification, we investigated separation and analysis methods for both types and found a suitable sample of each: RCA-120-Agarose column for separation and ELISA using anti-thrombomodulin antibody and RCA lectin for analysis.

Increased anticoagulant activity of recombinant thrombomodulin modified with glycosaminoglycan

Thrombomodulin (TM) is a thrombin receptor on the endothelial cell surface, effective as an anticoagulant by changing procoagulant thrombin to an anticoagulant one. As rabbit TM with glycosaminoglycan (GAG) has a more potent anticoagulant activity than that without GAG, we expressed recombinant GAG-modified urinary thrombomodulin (GAG-UTM) in C-127 cells. The effect of an additional GAG chain on anticoagulant activity was investigated in comparison with unmodified recombinant UTM (r-UTM). In vitro, the activity of cleavage of fibrinogen by thrombin or prothrombinase activity was more potently depressed by GAG-UTM than by r-UTM, and the generation of activated protein C by TM-thrombin complex was accelerated by GAG modification. The acceleration of antithrombin III-dependent anticoagulant activity was shown only by GAG-UTM. Parameters like thrombin time, prothrombin time and activated partial thromboplastin time in human plasma were prolonged by GAG-UTM more than by r-UTM. In vivo, the effect of GAG-UTM and r-UTM in endotoxin-induced disseminated intravascular coagulation (DIC) rats was investigated using hematological parameters. GAG-UTM and r-UTM significantly reduced the decrease in fibrinogen and platelet number induced by endotoxin at the dosage of 0.1 and 1.0 mg/kg/h, respectively, suggesting that the antithrombotic effect of GAG-UTM in endotoxin-induced DIC rats was 10-fold as potent as that of r-UTM. GAG-UTM reduced the prolongation of the bleeding time induced by endotoxin, while r-UTM accelerated it. These results suggest that the addition of a GAG chain may increase availability as an anticoagulant.

Baicalin, an inhibitor of HIV-1 production in vitro

The flavonoid baicalin markedly inhibits replication of human immunodeficiency virus type 1 (HIV-1) in a concentration-dependent manner in normal peripheral blood mononuclear cells (PBMC) stimulated with phytohemagglutinin (PHA) in vitro. The effect was more pronounced when the cells were pretreated with baicalin. Furthermore, baicalin inhibits HIV-1 replication in PHA-stimulated PBMC from asymptomatic HIV-1-seropositive carriers. The 50% inhibitory concentration for HIV-1 replication was approximately 0.5 microg/ml. At the concentration of 2 microg/ml of baicalin, copy numbers of HIV-1 proviral DNA were approximately 50 times less than in untreated controls. In a cell-free infection system, baicalin inhibited the activity of HIV-1 reverse transcriptase (RT), but not the activity of human DNA polymerases alpha and gamma (DNA polymerase beta was slightly inhibited), suggesting that the anti-HIV-1 effect of baicalin may at least partly be due to inhibition of HIV-1 RT.

Protein C activation by recombinant thrombomodulin in plasma

Recombinant glycosaminoglycan-modified urinary thrombomodulin (GAG-UTM), which partially improved the amino acid sequence of human urinary thrombomodulin (UTM), was expressed in C127 cells. GAG-UTM accelerates protein C activation by thrombin and also thrombin inhibition by antithrombin III (ATIII) in the buffer system. Both accelerating activities of GAG-UTM are more potent than those of unmodified recombinant UTM (r-UTM) without a GAG chain. As ATIII in plasma also inhibits protein C activation by a thrombin-thrombomodulin complex, we studied whether GAG-UTM accelerates protein C activation in plasma. GAG-UTM suppressed the generation of thrombin in activating plasma protein C stronger than r-UTM. By Western blot analysis using anti-protein C antibody, activated protein C was generated by GAG-UTM more than by r-UTM. From these results, the acceleration of activated protein C formation by GAG-UTM was confirmed in plasma too.

Nucleotide sequence variation of human T-lymphotropic virus type II in Vietnam

A high rate of human T-lymphotropic virus type II (HTLV-II) infection has been documented in intravenous drug abusers (IVDAs) in South Vietnam. We have investigated the molecular characteristics of the virus and have shown that one HTLV-II subtype is predominant in Ho Chi Minh City. This molecular subtype, HTLV-IIb, was identified in a number of South Vietnamese by nucleotide sequence analysis of the long terminal repeat (LTR) region. HTLV-IIa was not found. These findings suggest that HTLV-IIb is endemic in IVDAs in South Vietnam, although IVDAs in urban areas in North America are predominantly infected with HTLV-IIa.

Correlation of titer of antibody to principal neutralizing domain of HIVMN strain with disease progression in Japanese hemophiliacs seropositive for HIV type 1

With the use of the principal neutralizing determinant (PND) peptide-based ELISA to measure anti-PND antibodies that specifically bound synthetic peptides derived from HIVIIIB, HIVMN, HIVRF, HIVSC, HIVWJM-2, HIVAf1l.con, or HIVAf2.con, type-specific antibodies to the HIVMN peptide were studied in 350 serum specimens from Japanese with hemophilia A who had been injected with known unheated factor VIII concentrates until 1985 and had been infected with HIV-1 subtype B. These antibodies were not found in any of the seronegative sera of hemophiliacs, patients with autoimmune diseases, or normal healthy controls. Further, all hemophiliacs rapidly progressing to AIDS and death among the 95 hemophiliacs in a restricted Nara area had antibody titers of less than 20 and their low levels preceded the rapid progression to the disease state. In contrast, slowly progressing hemophiliacs maintained an antibody titer of more than 100 from the initial stages of viral infection and remained asymptomatic. Sequence analysis of the V3 regions of HIV-1 indicated that the hemophiliacs who maintained a high anti-PNDMN antibody level showed a conserved MN sequence. In contrast, the HIV-infected hemophiliacs with nonreactivity in the ELISA showed sequence changes in the neutralizing epitopes of HIVMN. The dynamic of the serum anti-PNDMN antibody titer appear to be a characteristic indicator of the progression of the HIV-infected status in Japanese hemophiliacs seropositive for HIV-1.

Human T-lymphotropic virus type II in Japan

Serum specimens were assayed for human T-lymphotropic virus type II(HTLV-II) infection in 1,500 individuals known to be seropositive for HTLV-I and 30,000 blood donors in Japan. All HTLV-I-positive individuals were negative for HTLV-II. However, one of the blood donors was clearly seropositive for HTLV-II. Further, the donor was shown to be positive for HTLV-IIb. Here we report at least one case with HTLV-II in Japan and discuss the origin of the infection.

Protective immune responses induced by secretion of a chimeric soluble protein from a recombinant Mycobacterium bovis bacillus Calmette-Guérin vector candidate vaccine for human immunodeficiency virus type 1 in small animals

A recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) vector-based vaccine that secretes the V3 principal neutralizing epitope of human immunodeficiency virus (HIV) could induce immune response to the epitope and prevent the viral infection. By using the Japanese consensus sequence of HIV-1, we successfully constructed chimeric protein secretion vectors by selecting an appropriate insertion site of a carrier protein and established the principal neutralizing determinant (PND)-peptide secretion system in BCG. The recombinant BCG (rBCG)-inoculated guinea pigs were initially screened by delayed-type hypersensitivity (DTH) skin reactions to the PND peptide, followed by passive transfer of the DTH by the systemic route. Further, immunization of mice with the rBCG resulted in induction of cytotoxic T lymphocytes. The guinea pig immune antisera showed elevated titers to the PND peptide and neutralized HIVMN, and administration of serum IgG from the vaccinated guinea pigs was effective in completely blocking the HIV infection in thymus/liver transplanted severe combined immunodeficiency (SCID)/hu or SCID/PBL mice. In addition, the immune serum IgG was shown to neutralize primary field isolates of HIV that match the neutralizing sequence motif by a peripheral blood mononuclear cell-based virus neutralization assay. The data support the idea that the antigen-secreting rBCG system can be used as a tool for development of HIV vaccines.

[Induction of protective immune responses by a chimeric soluble protein from a recombinant BCG vector candidate vaccine to HIV-1]

We have been isolated HIV strains from blood specimens of HIV infected individuals in Japan for these 6 years. The number of specimens tested reached approximately 1,700 that ninety percent of them were from hemophiliacs repeatedly injected blood products from the United States. More than 300 of field HIV were successfully isolated from the samples. The isolation rates has decreased to 30 percent in 1993 from 40 percent in 1992, suggesting that treatment with anti-HIV drugs such as AZT and/or ddI may be effective to HIV-infected individuals. Further, both of the viral and genomic sequences of HIV were classified to be clade B virus. The clinical isolates that expressed IHIGPGRAFY sequence at the center of the HIV-V3 domain were found to be neutralized by an anti-clade B-V3 monoclonal antibody, mu 5.5. By individual levels, when asymptomatic seropositives have progressed to disease-states, neutralization core motif of GPGR in approximately 6% of the viruses has changed to GPGG and hydrophilic amino acid changed to hydrophobic amino acid, correlating the loss of binding activity to PND-peptide of Japanese Consensus virus. Further, rapid progressors to HIV-induced diseases showed decreased activity of the binding antibody. By using the Japanese consensus sequence of HIV-1, we successfully constructed chimeric protein secretion vectors by selecting an appropriate insertion site of a carrier protein, and established the PND-peptide secretion system in BCG. The recombinant BCG inoculated guinea pigs were initially screened by delayed-type hypersensitivity (DTH) skin reactions to the PND peptide followed by passive transfer of the DTH by the systemic route.(ABSTRACT TRUNCATED AT 250 WORDS)

Species specificity of pharmacological characteristics of CCK-B receptors

Novel CCK-B receptor antagonists, tetronothiodin and L-156,586, showed different affinities for CCK-B receptors in brain membranes from human, rat, guinea pig and mouse. [125I]CCK-8 bound to these membranes with a similar affinity. However, tetronothiodin was most potent in rat (IC50 = 3.6 nM), followed by guinea pig (96 nM), human (210 nM) and mouse (280 nM). L-156,586 bound with highest affinity to membranes from guinea pig (11 nM), and with lowest affinity to membranes from mouse (220 nM). These results suggest the existence of species specificity of CCK-B receptors, and that these two compounds are useful tools for discrimination between these receptors.

Activation of CCK-B receptors elevates cytosolic Ca2+ levels in a pituitary cell line

Cytosolic Ca2+ levels ([Ca2+]i) in GH3 cells, a rat anterior pituitary tumor cell line, were monitored with fura-2 by fluorescence measurements. Cholecystokinin octapeptide (CCK-8) produced a transient elevation of [Ca2+]i. The elevation of [Ca2+]i by CCK-8 was inhibited by L-365,260, but not by devazepide. It was still observed when extracellular Ca2+ was eliminated, indicating that CCK-8 mobilizes Ca2+ from intracellular storage sites after interaction with CCK-B receptors. Cholecystokinin octapeptide increased the turnover of phosphatidylinositol, but it did not affect cyclic AMP levels. A possible involvement of phosphatidylinositol breakdown and calcium mobilization in the transduction system of CCK-B receptors in GH3 cells is suggested.

GH3 cells, an anterior pituitary cell line, express CCK-B receptors

We found that GH3 cells, a rat anterior pituitary tumor cell line, expressed a single class of high-affinity binding sites for radiolabeled cholecystokinin octapeptide (CCK-8) with a Kd of 48 pM. The binding sites had high affinity for CCK-8, CCK-4, gastrin I, and L-365,260 (CCK-B antagonist), and had low affinity for devazepide (CCK-A antagonist), indicating that the binding sites are CCK-B receptors. GTP and its stable analogues inhibited radiolabeled CCK-8 binding to GH3 cell membranes, suggesting a coupling of CCK-B receptors to a G-protein.

Tetronothiodin, a novel CCKB receptor ligand, antagonizes cholecystokinin-induced Ca2+ mobilization in a pituitary cell line

We found a novel nonpeptide CCKB receptor antagonist, tetronothiodin (Ro 09-1468), in the culture broth of Streptomyces sp. NR0489. The structure of the compound (C31O8H38S), which has a 19-membered ring with an alpha-acyltetronic acid and tetrahydrothiophene moiety, is completely different from that of any known CCK receptor antagonist. Tetronothiodin inhibited [125I]CCK-8 binding to rat brain CCKB receptors with an IC50 of 3.6 nM, whereas it showed only weak affinity for rat CCKA receptors (IC50 = 70 microM). As demonstrated autoradiographically, tetronothiodin concentration dependently inhibited [125I]CCK-8 binding to CCKB receptors in rat forebrain slices. The effects of tetronothiodin on cytosolic Ca2+ concentrations in GH3 cells, a rat anterior pituitary tumor cell line, were investigated with the fura-2 method. Tetronothiodin inhibited CCK-8-induced Ca2+ mobilization without affecting basal cytosolic Ca2+ concentrations. In conclusion, tetronothiodin is a new, potent and highly selective CCKB receptor antagonist. It is a useful tool for investigating the pharmacological and physiological roles of CCKB receptors.

Effects of calphobindin II (annexin VI) on procoagulant and anticoagulant activities of cultured endothelial cells

Effects of human placental calphobindin II (CPB-II) on the protein C activation and prothrombin activation on the cell surface of cultured calf pulmonary arterial endothelial cells have been investigated. CPB-II inhibited thrombin generation by factor Xa bound to the surface of the cultured endothelial cells in a dose-dependent manner. The amount (IC50) of CPB-II causing the inhibition at 50% was estimated to be approximately 10 nM. CPB-II was found to be ineffective, however, in the protein C activation by thrombin-thrombomodulin (TM) complex on the cell surface. Assay using purified TM revealed that CPB-II was able to exhibit the inhibitory potency for the protein C activation exclusively in the reconstituted system with negatively charged phospholipids. These results suggest that the neutral phospholipids participate in the protein C activation through the thrombin-TM system on the endothelial cell surface. The ability of CPB-II to inhibit procoagulant activity without affecting anticoagulant activity on the cultured endothelial cells is probably related to its potential physiological function, while it is able to exert various degrees of influence upon these activities in blood coagulation by interacting with negatively charged phospholipids in vitro.

Phospholipid-binding properties of calphobindin-II(annexin VI), anticoagulant protein from human placenta

Calphobindin-II (CPB-II, annexin VI), is a calcium dependent phospholipid binding protein that can be classified as a member of the annexin family. The phospholipid-binding properties of CPB-II were investigated by measuring the binding constants of [125I]-CPB-II using phospholipid vesicles consisting of 80% phosphatidylcholine and 20% phosphatidylserine. A dissociation constant (Kd) of CPB-II with the phospholipid vesicles was determined to be 0.2 to 0.3 nM in the presence of Ca2+ ranging from 0.3 to 30 mM. The number of CPB-II capable of binding to the phospholipid vesicles at 0.3 mM Ca2+ decreased to about 1/2 in the presence of Ca2+ of more than 1 mM. Prothrombin and factor X were effective in competing with the binding of CPB-II to the phospholipid vesicles, although their affinities were lower by two or three orders of magnitude than that of unlabeled CPB-II at 30 nM Ca2+. Competitive effects of CPB-II, calphobindin-I (CPB-I, annexin V) and calphobindin-III (CPB-III, annexin III) on binding of [125I]-CPB-II to phospholipid vesicles, were similarly observed.

Cyclothiazomycin, a novel polythiazole-containing peptide with renin inhibitory activity. Taxonomy, fermentation, isolation and physico-chemical characterization

Cyclothiazomycin is a novel renin inhibitor produced by Streptomyces sp. NR0516. It was isolated from fermentation broth by extraction with butyl alcohol, QAE-Toyopearl column chromatography and preparative HPLC. Cyclothiazomycin, which was determined to be a unique polythiazole-containing bicyclic peptide, exhibited inhibitory activity against human plasma renin with IC50 being 1.7 microM.

Structure and properties of calphobindin II, an anticoagulant protein from human placenta

The structure of human placental calphobindin-II (CPB-II) was investigated by amino acid composition and amino acid sequence analyses of peptides generated by protease digestion of the protein. The 45 peptides obtained from the lysyl endopeptidase digest of CPB-II, and the amino-terminal peptide prepared from its tryptic digest, were analyzed, and they accounted for over 98% of total amino acids of CPB-II. The structure of CPB-II determined by protein sequencing was identical to that previously predicted from its cDNA sequence (Iwasaki, A. et al. (1989) J. Biochem. 106, 43-49), except for the amino terminus. Since the amino terminus of CPB-II was blocked to Edman degradation, fast-atom-bombardment mass spectrometric analysis was used to demonstrate that the amino-terminal residue was acetyl-alanine. The carboxyl-terminal residue of CPB-II was identified as aspartic acid by the hydrazinolytic procedure. Calcium-binding studies indicated that 1 mol of CPB II binds 1 mol of calcium in the absence of phospholipid and 8 mol of calcium in the presence of phospholipid.

Isolation and characterization of an anticoagulant protein from human placenta

An anticoagulant protein was purified from the EDTA extract of human placental tissue. The purified protein had a molecular weight of 73,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis under both reducing and non-reducing conditions. Because this protein had the ability to bind phospholipids such as phosphatidylserine, phosphatidylinositol, and cardiolipin in the presence of Ca2+, this protein was designated as calphobindin II (CPB-II). CPB-II prolonged the clotting time of normal plasma when coagulation was induced by tissue factor, cephalin and ellagic acid or recalcification, but did not affect thrombin-initiated fibrin formation. CPB-II also inhibited the activation of prothrombin by the complete prothrombinase complex or factor Xa-phospholipid-Ca2+ but not that by phospholipid-free factor Xa. In addition, CPB-II had an inhibitory activity against phospholipase A2.

Inhibition of mitogen-stimulated T lymphocyte proliferation by calcitonin gene-related peptide

The effect of calcitonin gene-related peptide (CGRP) on mouse lymphocyte proliferation stimulated by mitogens was studied. CGRP (10(-10)-10(-7) M) dose-dependently inhibited the proliferative response of mouse lymph node cells and spleen cells stimulated by T cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA), whereas a B cell mitogen lipopolysaccharide (LPS) did not inhibit this response. The maximal inhibition by this peptide was 50% to 80% at 10(-8) and 10(-7) M. The addition of 10(-8) and 10(-7) M CGRP to lymph node cell cultures 24 hr after stimulation with Con A or PHA also had a significant inhibitory effect on the proliferative response. Furthermore, in the same concentration range (10(-10)-10(-7) M) CGRP increased intracellular cyclic AMP concentration in nylon wool nonadherent cells, but not in nylon wool adherent cells. CGRP had no significant effect on intracellular cyclic GMP concentration. In addition, specific binding of CGRP was observed in mouse spleen cells. Our present study suggests that CGRP inhibits the proliferative response of T lymphocytes to the mitogens by interacting with cell receptors coupled with adenylate cyclase. CGRP may be implicated in the regulation of T cell function.

Proteose peptone enhances production of tissue-type plasminogen activator from human diploid fibroblasts

Proteose peptone markedly enhanced the production of human tissue-type plasminogen activator (t-PA) from confluently cultured cell of human diploid fibroblasts. The cells continued synthesizing and secreting high levels of t-PA under periodic replacement of medium containing proteose peptone for more than one month. The highly increased activity correlated with equally increased levels of t-PA antigen and concomitantly increased levels of t-PA specific mRNA.

Structure and expression of cDNA for an inhibitor of blood coagulation isolated from human placenta: a new lipocortin-like protein

An inhibitor of blood coagulation, a new protein with an apparent molecular weight of 34,000 and an isoelectric point of 4.9, was purified from human placental tissue by EDTA extraction. Five cDNA clones were isolated from the human placental lambda gt11 cDNA library using the mouse monoclonal antibody raised against the coagulation inhibitor as the probe. The longest insert consists of 1,566 nucleotides, and contains 960 nucleotides entirely encoding the 320 amino acids of the inhibitor, and a poly A tail. The deduced amino acid sequence was corroborated by chemical analyses of the protein. The entire amino acid sequence shows homology to those of lipocortin I, lipocortin II, and endonexin-related proteins. The cDNA for the inhibitor was expressed in Escherichia coli under the regulation of the trc promotor of the plasmid pKK233-2. The resulting recombinant protein manifested inhibitory activities against both blood coagulation and phospholipase A2 activity, as did the coagulation inhibitor isolated from human placenta.

Characterization of picomolar affinity binding sites for [125I]-human calcitonin gene-related peptide in rat brain and heart

We have characterized picomolar affinity binding sites for human calcitonin gene-related peptide (CGRP) in rat brain and heart (atria and ventricle) membranes. By saturation analysis, apparent dissociation constant (KD) values of high affinity sites for [125I]-human CGRP are 9 approximately 15 pM (brain), 34 pM (ventricle) and 85 pM (atria). Low affinity sites with KD values of about 50 nM are found in rat brain and ventricle, but not in atria. Human and rat CGRP potently inhibited [125I]-human CGRP binding to these high affinity sites with apparent inhibition constant (Ki) values comparable to their KD values. Salmon calcitonin marginally inhibited these binding with Ki values between 0.1 microM and 1 microM. Extremely potent cardiovascular and gastrointestinal actions of CGRP might be mediated through CGRP binding sites with picomolar affinity which are similar to those we characterized in this study.

Preventive effects of the cerebral circulation improver 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-4-([4-(2-methoxyphenyl)- 1-piperazinyl]methyl)isoquinoline on stroke symptoms in stroke-prone spontaneously hypertensive rats

Stroke-prone spontaneously hypertensive rats (SHRSP) were treated with food admixed, 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-4-([4-(2-methoxyphenyl)-1- piperazinyl]methyl)isoquinoline (Ro 22-4839), a novel cerebral circulation improver, for a period of 15 weeks starting from 5 weeks of age at an average daily dose of 30.6 or 66.0 mg/kg. As compared with normotensive Wistar Kyoto rats, SHRSP in the control group rapidly developed severe hypertension (244 mmHg at the end of the experiments) accompanied with deterioration of cardiovascular parameters including left ventricular hypertrophy, reduction in pumping ability and increase in peripheral vascular tone. At 20 weeks of age (i.e. at the end of experiments), 75% of SHRSP developed stroke signs and concomitant cerebral edema evidenced by the increases in water and sodium contents in the brain. These stroke symptoms were accompanied with a profound externalized shape change of erythrocytes after in vitro treatment with Ca2+ and ionophore A23187, an increased plasma level of thiobarbituric acid reacting substance (TBARS), a measure of lipid peroxides, and a decreased sensitivity of platelets to ADP. The long-term treatment with Ro 22-4839 prevented the progress of stroke and cerebral edema, although the deteriorated cardiovascular parameters were not prevented by the treatment. This compound was also found to prevent the hypersusceptibility of erythrocyte membrane to Ca2+-ionophore and Ca2+, the hypoaggregability of platelets and the elevated plasma TBARS in SHRSP. These results indicate that the beneficial effects of Ro 22-4839 in SHRSP may be attributable to its calmodulin antagonistic and anti-lipid peroxidative actions but not to its hypotensive action.

Calmodulin antagonistic action of the cerebral circulation improver 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-4- ([4-(2-methoxyphenyl)-1-piperazinyl]methyl)isoquinoline

6,7-Dimethoxy-1-(3,4-dimethoxybenzyl)-4-([4-(2-methoxyphenyl)-1- piperazinyl]methyl)isoquinoline (Ro 22-4839) is a new cerebral circulation improver with vasospasmolytic properties. Preliminarily, Ro 22-4839-induced arterial relaxation was confirmed under the treatment of various constrictors and it was hardly overcome by addition of extra calcium. In this study the mode and site of action of this agent were further explored. Ro 22-4839 was found to more strongly inhibit the superprecipitation of chicken gizzard smooth muscle actomyosin (IC50 = 2.0 mumol/l) than trifluoperazine (38 mumol/l) and W-7 (N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide) (220 mumol/l), an in vitro model for relaxation-contraction coupling of the smooth muscle in which calmodulin is known to play an important role through phosphorylation of myosin light chain kinase. The calmodulin antagonistic action of Ro 22-4839 was also demonstrated in other calmodulin-related reaction systems such as phosphodiesterase and hydrophobic fluorescent probe, but was very weak in Ca2+, Mg2+-ATPase of rat erythrocyte membrane. Thus, Ro 22-4839 was suggested to have a relative preference for smooth muscle contraction process unlike trifluoperazine and W-7. Moreover, Ro 22-4839 prevented the decrease in erythrocyte deformability induced by hyperosmolarity or intracellular Ca2+ accumulation, like trifluoperazine and W-7. However, Ro 22-4839 itself caused hardly an internal stomatocytic shape of erythrocytes in contrast to known calmodulin antagonists. Further, Ro 22-4839 inhibited erythrocyte membrane rupture, platelet aggregation and lipid peroxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Spasmolytic action of the cerebral circulation improver 6,7-dimethoxy-1- (3,4-dimethoxybenzyl)-4-[( 4-(2-methoxyphenyl)-1-piperazinyl]methyl) isoquinoline in isolated canine vessels

Vasodilating action of a new calmodulin antagonist, 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-4-[( 4-(2- methoxyphenyl)-1-piperazinyl] methyl) isoquinoline (Ro 22-4849) was examined in various isolated canine vessels. Ro 22-4839 was found to dilate basilar and middle cerebral arteries and to non-selectively antagonize submaximal contraction of these arteries under the treatment of various constrictors (K+, Ca2+, PGF2 alpha (dinoprost), serotonin and incubated blood) with IC50 values ranging from 0.043 to 1.69 mumol/l. Vasospasmolytic action of the compound in these cerebral arteries was 9 and 20 times greater than those in coronary and femoral arteries, respectively. The arterial relaxation by Ro 22-4839 was hardly overcome by addition of extra calcium and Ro 22-4839 did not alter calcium channels in the guinea-pig papillary muscle, although the compound inhibited the tension development, confirming its calmodulin antagonistic properties. Ro 22-4839 inhibited norepinephrine (NE)-induced contraction of femoral arterial strips concentration-dependently, and prevented NE-induced lethal extravasation in mice with an ED50 value of 1.96 mg/kg p.o. In in vitro [3H]-dihydroergocryptine binding assay and ex vivo [3H]-WB-4101 (2-[(2',6'-dimethoxy)phenoxyethylamino] methylbenzodioxan) binding assay, the compound showed a potent inhibitory action on alpha 1-adrenoceptor. These findings indicate that Ro 22-4839 exerts the spasmolytic effects on cerebral vessels through calmodulin antagonistic properties combined with alpha 1-adrenoceptor blocking action.

Leukemia serum reactive with retrovirus-related antigen in normal human placenta

Serum antibody reactive with a retrovirus-related p30 antigen in human normal term placenta was investigated and characterized by immunohistologic and immunoblotting methods. Sera obtained from patients with acute leukemia and malignant lymphoma were used as first antibody, and cryostat sections of placenta were the target antigen. An IgM antibody that reacted mainly with the basal aspect of syncytiotrophoblast of chorionic villi, where a putative human endogenous retrovirus p30 antigen is located, was directed by indirect immunofluorescence. This antibody activity, termed anti-basal aspect of syncytiotrophoblast (anti-BAST), was detected in the sera of many patients with acute leukemia (AML, ALL) and malignant lymphoma, and less frequently in sera of pregnant women and normal controls. As shown by immunoblotting analysis, the main reactive antigen recognized by anti-BAST was a non-glycosylated 32-kDa placental protein which was antigenically related to SSAV p30. A non-glycosylated 19-kDa protein was also considered to be one of the anti-BAST-corresponding antigens. This suggests the presence of a new antigen-antibody system of human retrovirus(es) revealed by subinfectious antigenic expression and by specific antibody activity in conditions of human health and disease, particularly, acute leukemias and malignant lymphomas of common types.

[Fundamental studies with respect to plasma exchange by using continuous-flow centrifuge system and the clinical trial in patients with myasthenia gravis]

A plasma exchange by using the continuous-flow centrifuge blood cell separator (IBM 2997) was carried out in 13 patients with various diseases including myasthenia gravis. The effects of the plasma exchange on blood components and side effects during the procedure were evaluated. In addition, 5 cases with severe myasthenia gravis who had failed to respond to medication were treated by plasma exchange, and the results were as follows: 1. Red blood cells, hemoglobin and hematocrit levels were significantly decreased while white blood cells inclined to increase after plasma exchange. In serum electrolytes and proteins there were no changes. 2. The side effects such as itching and eruption were observed in 46% of the patients. However, they disappeared within a short period. 3. In 2 cases with myasthenia gravis, a significant improvement in muscle weakness was observed by plasma exchange. In these cases, serum levels of the acetylcholine receptor antibody and the circulating immune complex were decreased, as compared with the previous levels. These parameters showed no correlation with severity of the disease.

Determination of the anomeric configurations of Corbicula ceramide di- and trihexoside by chromium trioxide oxidation

The anomeric configurations of Corbicula ceramide dihexoside and ceramide trihexoside were determined by chromium trioxide oxidation and the structures of these lipids were shown to be Man-beta(1 leads to 4)-Glc-beta(1 leads to 1)-ceramide and Man-alpha(1 leads to 4)-Man-beta(1 leads to 4)-Glc-beta(1 leads to 1)-ceramide. These results are compatible with those obtained by enzymic hydrolysis reported previously.