Crystallization and preliminary X-ray crystallographic studies on a Fab fragment of the mouse anti-human Fas monoclonal antibody HFE7A.

The Fas-Fas ligand system is involved in apoptosis. The mouse anti-human Fas monoclonal antibody HFE7A (m-HFE7A) has a potential use in human therapy against autoimmune diseases such as rheumatoid arthritis. Information on the three-dimensional structure is essential for antibody humanization. Crystals of an antigen-binding fragment (Fab) of m-HFE7A were obtained by the hanging-drop vapour-diffusion method using sodium citrate as a precipitant and 2-methyl-2,4-pentanediol as an additive. Fast optimization to produce single crystals suitable for X-ray analysis was achieved by the streak-seeding technique. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 43.4, b = 74.0, c = 133.8 A. The crystals diffract at least to 2.5 A resolution.

Clinicopathological features of myeloid/natural killer (NK) cell precursor acute leukemia.

Four patients (three males and one female) were diagnosed as myeloid/natural killer (NK) cell precursor acute leukemia in our department. Two patients showed the extramedullary involvement at initial presentation. Leukemic cells expressed CD7, CD33, CD45 and CD56 in all patients. Additionally, CD13, CD34, HLA-DR, cytoplasmic CD3 and myeloperoxidase were expressed in some patients. Trisomy 10 was found in two patients, which has not been reported in this disease. Therefore, myeloid/NK cell precursor acute leukemia might be rather heterogeneous especially in chromosomal abnormality though it seemed to constitute the distinct clinical entity among acute myeloid leukemia of M0 subtype.

[Discrimination of leukoencephalopathy from leukemic cell invasion by MR spectroscopy in a patient with acute lymphoblastic leukemia].

A 58-year-old man was admitted to our hospital in November 1992 because of fever and arthralgia. He was given a diagnosis of acute lymphoblastic leukemia and treated with an Ad-VP regimen, which resulted in complete remission. After two courses of consolidation therapy and intrathecal (IT) injections of methotrexate, Ara-C, and prednisolone the patient received high-dose Ara-C plus VP-16 followed by recombinant human G-CSF for the collection of peripheral blood stem cells. However, he relapsed with the appearance of leukemic cells in cerebrospinal fluid (CSF), and was accordingly given IT injections 8 more times. After the disappearance of leukemic cells from CSF, the patient received a peripheral blood stem cell transplant (PBSCT) and achieved rapid hematopoietic recovery. However, he suffered mental aberrations and loss of consciousness 9 days after PBSCT. Proton magnetic resonance spectroscopy (1H-MRS) disclosed severe necrosis due to leukoencephalopathy in the frontal lobe and invasion of leukemic cells around the lateral ventricles. The patient did not receive any therapy for neurological symptoms because of severe necrosis in the frontal lobe, and died of bone marrow relapse in April 1995. MRS is useful for the discrimination of leukoencephalopathy from leukemic cell invasion.

B-90063, a novel endothelin converting enzyme inhibitor isolated from a new marine bacterium, Blastobacter sp. SANK 71894.

A novel endothelin-converting enzyme (ECE) inhibitor, B-90063, was isolated from the culture supernatant of the newly discovered marine bacterium Blastobacter sp. SANK 71894. Based on spectral analyses and chemical reactions, the structure of B-90063 was determined to be bis[6-formyl-4-hydroxy-2-(2'-n-pentyloxazol-4'-yl)-4-pyridon -3-yl]-disulfide (1a). Human and rat ECEs were inhibited more potently by B-90063, with respective IC50 values of 1.0 and 3.2 microM, than were other neutral endopeptidases such as NEP and type-I and -IV collagenases. B-90063 also inhibited the binding of ET-1 to rat ET(A) and bovine ET(B) receptors, though its antagonistic activities were weak. B-90063, thus, may abolish the physiological actions of endothelins through the ECE inhibitory and receptor antagonistic mechanisms.

A-53930A and B, novel N-type Ca2+ channel blockers.

A-53930A, B and C, which inhibit N-type Ca2+ channels, were isolated from the culture broth of Streptomyces vinaceusdrappus SANK 62394. A-53930A and B were new compounds which contained a carbamoyl group on the 6-hydroxyl group of the D-gulosamine part of streptothricin. A-53930C was identical to streptothricin B. A-53930A, B and C inhibited [125I]omega-conotoxin MVIIA binding to N-type Ca2+ channels (IC50= 0.17, 0.091 and 0.071 microM), but did not inhibit [3H]PN200-110 binding to L-type Ca2+ channels (IC50 > 50 microM). These compounds also inhibited [3H]norepinephrine release from chick cerebral cortex synaptosomes (IC50=91.0, 20.6 and 39.5 microM), indicating these compounds selectively block N-type Ca2+ channels which are important for neurotransmitter release. It was also revealed that although A-53930C had antimicrobial activity against gram-negative and -positive bacteria and fungi, A-53930A and B showed weak activity only against gram-negative bacteria.

Nahocols and isonahocols, endothelin antagonists from the brown alga, Sargassum autumnale.

Novel endothelin antagonists, nahocols A, A1, B, C, D1 and D2, and isonahocols D1 and D2, were isolated from the brown alga, Sargassum autumnale. Their structures were determined through detailed analysis of NMR spectra and chemical reactions. Nahocols have an aryl prenyl ether structure, which are speculated to be biogenetic precursors of the ubiquitous prenyl hydroquinones or prenyl benzoquinones in the plant and animal kingdoms.

Solution structure of CINC/Gro investigated by heteronuclear NMR.

Cytokine-induced neutrophil chemoattractant (CINC/Gro) is a chemotactic factor for neutrophils in the rat and a member of the CXC chemokine family. The refined three-dimensional structure of CINC/Gro was derived with the aid of heteronuclear magnetic resonance spectroscopy and a hybrid method of distance geometry and simulated annealing. The backbone atomic r.m.s. differences for 19 structures about the mean coordinates for residues 7 to 70 are 0.69+/-0.15 A for the dimer and 0.56+/-0.13 A for the monomer. The N terminal region containing an ELR sequence, an essential motif for chemotactic activity, is disordered in solution, as in other CXC chemokines. The dimer structure consists of a six-stranded anti-parallel beta sheet with two C-terminal alpha helices on the beta sheet. The overall dimer structure of CINC/Gro is similar to that of human MGSA, though the backbone r.m.s.d.s between CINC/Gro and the two MGSA structures were high (1.81 and 2.34 A for the monomer) in spite of the high sequence homology (67%). The major difference resides in the relative position of the C-terminal alpha helix with respect to the beta sheet. This results in a difference of interhelical distances in the dimer: wider (15 A) in CINC/Gro, as in IL-8, than in MGSA (11.7 and 10 A).

Flow cytometric analysis of Thy-1 expression in myelodysplastic syndrome.

We analyzed the expression of Thy-1 (CD90) antigen on CD34+ bone marrow mononuclear cells (BMMNC) obtained from 25 patients with myelodysplastic syndrome (MDS) by two-color flow cytometry. Five of nine patients (55.6%) with refractory anemia with excess of blasts (RAEB) and two of 16 (12.5%) with RAEB in transformation (RAEB-t) showed more than 20% of Thy-1 expression of their CD34+ BMMNC. Regarding chromosomal abnormalities, -5/5q- or -18 might be correlated with the expression of Thy-1 on CD34+ BMMNC in MDS. Nine patients were analyzed twice, once before and once after leukemic transformation and showed no significant change in Thy-1 expression. These results show that Thy-1 was expressed on CD34+ BMMNC in certain patients with MDS before leukemic transformation and that it was maintained during the disease progression. In contrast, expression of Thy-1 did not seem essential to the leukemic transformation in MDS though the patients with high Thy-1 expression might have poorer prognosis compared with those with low Thy-1 expression.

Subunit association and monomer structure of CINC/Gro revealed by 1H-NMR.

Rat CINC/Gro is a 72 residue chemotactic factor of neutrophils, and a member of the CXC chemokine family, that includes IL-8 and MGSA/GRO. Although the three-dimensional structure of CINC/Gro had previously been determined to be that of a dimer with 200 mM NaCl, it was shown on both ultracentrifugation analysis and 1H-NMR spectral analysis that CINC/Gro exists mainly as a monomer at a physiological concentration, similar to other proteins belonging to this family. By reducing the NaCl concentration, the equilibrium could be shifted to the monomer, making it possible to observe the monomer and dimer resonances in 1H-NMR spectra. There were no significant chemical shift changes of alpha protons in the beta sheet between the monomer and dimer, suggesting that the beta sheet structure was retained in the monomer. Instead, the chemical shift changes of a protons were significant at I18 and K21, which are located in the long loop region interacting with the alpha helix, and V59 at the beginning of the a helix, indicating structural changes in the relative positions of the alpha helix and beta sheet.

Serum thrombopoietin levels in patients undergoing autologous peripheral blood stem cell transplantation.

Recently, the ligand for c-mpl has been cloned and initial studies have shown it to be the platelet regulatory factor, thrombopoietin (TPO). To elucidate the role of TPO in the reconstitution of megakaryopoiesis and platelet production after stem cell transplantation, we measured serum TPO levels in nine patients undergoing autologous peripheral blood stem cell transplantation (PBSCT) and in healthy volunteers. Serum TPO levels significantly correlated with the degree of peripheral thrombocytopenia and a strong inverse correlation between serum TPO level and platelet count was observed (r = -0.700, P < 0.001). Serum TPO levels began to rise as the platelet count decreased after chemotherapy, TPO levels peaked at over 25.00 fmoles/ml between days 0 and 10; TPO levels then decreased gradually as the platelet count began to rise. One patient with multiple myeloma received purified CD34+ peripheral blood stem cells. No difference was observed in the kinetics of serum TPO levels between unfractionated and purified PBSCT. These observations suggest that TPO plays a critical role in the reconstitution of megakaryopoiesis and platelet production after PBSCT.

Schizostatin, a novel squalene synthase inhibitor produced by the mushroom, Schizophyllum commune. II. Structure elucidation and total synthesis.

Schizostatin (1) has been isolated as a potent and selective inhibitor of squalene synthase. Its structure has been determined using spectroscopic methods: the compound is shown to be a diterpenoid which has a trans-dicarboxylic acid moiety. Total synthesis of schizostatin (1) was achieved by the highly regio- and stereoselective coupling reaction of an allylic bromide with a barium reagent. The Z-isomer 16 was also prepared using the stereoselective syn-addition of an organocopper reagent to acetylenedicarboxylate.

Epi-cochlioquinone A, a novel acyl-CoA : cholesterol acyltransferase inhibitor produced by Stachybotrys bisbyi.

A novel acyl-CoA : cholesterol acyltransferase (ACAT) inhibitor, designated epi-cochlioquinone A has been isolated from the fermentation broth of Stachybotrys bisbyi SANK 17777. The molecular formula, physicochemical properties, NMR spectroscopic analysis and X-ray crystallographic analysis revealed that this compound was a stereoisomer of cochlioquinone A, which has been previously reported as a nematocidal agent. It inhibited ACAT activity in an enzyme assay using rat liver microsomes with an IC50 value of 1.7 microM. However, it showed about 10-fold less potent inhibitory effect on plasma lecithin cholesterol acyltransferase (LCAT) than on ACAT. In addition, it inhibited in vivo cholesterol absorption in rats by 50% at 75 mg/kg.

Serum levels of endogenous and exogenous granulocyte colony-stimulating factor after autologous blood stem cell transplantation.

Although the administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) enhances myeloid engraftment and reduces infectious morbidity after autologous and allogeneic bone marrow transplantations, the effect of rhG-CSF on neutrophil recovery in autologous blood stem cell transplantation (ABSCT) is controversial. We previously demonstrated that a low dose, delivered subcutaneously, of rhG-CSF (50 micrograms/m2) accelerates neutrophil recovery in ABSCT, but the optimal dosage of rhG-CSF is not known. To elucidate the effect of rhG-CSF on neutrophil recovery, we determined serum levels of endogenous and exogenously administered G-CSF in 24 patients receiving ABSCT. Of these, five received bolus subcutaneous injection of 50 micrograms/m2 rhG-CSF, 10 received 150 micrograms/m2, and nine received no rhG-CSF. Endogenous G-CSF levels rose immediately after ABSCT, and an inverse correlation was found between the serum level of G-CSF and the absolute neutrophil count (r = -0.73, p < 0.01). The pre-dose level in patients receiving rhG-CSF rose gradually, reaching a maximum between days 3 and 6. The level gradually decreased as the neutrophil count began to rise, even through administration of the same dose of rhG-CSF continued. Pharmacokinetic data showed that the half-life of elimination of G-CSF (t1/2) exceeded 15 hours during severe neutropenia but decreased during the recovery of neutrophils. These observations suggest that neutrophils provide a negative feedback mechanism for clearing G-CSF from the circulation. Pre-dose levels of G-CSF in patients receiving 50 micrograms/m2 rhG-CSF reached 10 ng/mL, equivalent to the concentrations used in clonogenic assay in vitro to stimulate myeloid progenitor cells.

Stereospecific taurine conjugation of the trans-OH metabolite (active metabolite) of CS-670, a new 2-arylpropionic acid nonsteroidal anti-inflammatory drug, in dogs.

CS-670, (+/-)-2-[4-(2-oxocyclohexylidenemethyl)phenyl]propionic acid, is a novel derivative of 2-arylpropionic acid non-steroidal anti-inflammatory drugs (profen NSAIDs). The major urinary metabolite of this drug from dogs was isolated and its chemical structure was determined by MS and NMR spectroscopy. The metabolite was identified as a taurine conjugate of the trans-OH form (trans-OH-taurine) which was first generated by stereoselective reduction of the double bond and the carbonyl function of the CS-670 molecule. The taurine conjugate was excreted in urine as the main metabolite, regardless of the optical configuration of CS-670 administered [2R)-enantiomer: 47.2% of the dose, (2S)-enantiomer: 70.9% of the dose]. The trans-OH-taurine was hydrolyzed by refluxing it in 6 N HCl without racemization. The released trans-OH was derivatized to diastereoamides with (+)-(R)-1-(1-naphthyl)ethylamine to examine the stereochemical properties of the 2-arylpropionic acid side chain. It was found that the configuration of the 2-carbon of the trans-OH-taurine was almost entirely (S). As the CoA thioesters are obligate intermediates for amino acid conjugation, the results suggest that the (2S)-enantiomer of the trans-OH metabolite serves as a substrate for canine acyl CoA ligase (EC 6.2.1.3) as well as the (2R)-enantiomer, but only the CoA thioester with a (2S)-configuration is a substrate for taurine N-acyl transferase. It is interesting to note that these results are not consistent with the chiral inversion mechanism by which the (2R)-enantiomers of profen NSAIDs are stereospecifically converted to CoA thioester intermediates.

Mobilization of peripheral blood progenitor cells by high-dose Ara C, VP-16 and recombinant human granulocyte colony-stimulating factor: factors affecting progenitor cell yields.

Forty seven patients with hematological malignancies were treated with high doses of cytosine arabinoside (Ara C; 12 g/m2) and etoposide (VP-16), followed by recombinant human granulocyte colony-stimulating factor (rhG-CSF; 50 micrograms/m2). Peripheral blood progenitor cells (PBPC) were collected during rapid leukocyte recovery using a CS-3000 blood cell separator. A blood volume of 9 liters was processed in each apheresis, with 162 apheresis procedures performed. The mean numbers of mononuclear cells (MNC) and colony-forming unit granulocyte-macrophage (CFU-GM) harvested per apheresis were 4.4 x 10(8)/kg and 142.5 x 10(4)/kg, respectively. A sufficient number of CFU-GM for engraftment (> 30 x 10(4)/kg) could be harvested by a single apheresis in 35 of 47 patients (74%). Various factors that influence the collection of progenitor cells were analyzed by univariate and multivariate analyses. The number and duration of previous chemotherapy cycles were the most significant factors affecting CFU-GM yield. In patients with malignant lymphoma, age also had an influence in addition to these two factors. MNC harvested had an impact on CFU-GM yields by univariate analysis. These observations suggest that high-dose Ara C plus VP-16 followed by G-CSF is an effective regimen for harvesting PBPC. PBPC should be collected in the early stage of first-line chemotherapy.

Carbohydrate structures of the glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen.

The glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen was treated with pepsin and glycopeptidase A to release asparagine-linked oligosaccharides. The reducing ends of the oligosaccharides were aminated with the fluorescent reagent 2-aminopyridine. The oligosaccharide derivatives were purified by gel permeation chromatography and reversed-phase HPLC. Their structures were determined by sequential exoglycosidase digestion and 500 MHz 1H-NMR spectroscopy. Four oligosaccharide structures, A, B, C, and D, were identified as the xylose-containing complex-type. They were present at a molar ratio of 8:1:6:1. By amino acid sequence analyses of the tryptic peptides, Asn-170 and Asn-333 of Cry j I were found to carry asparagine-linked oligosaccharides. [formula: see text]

Matlystatins, new inhibitors of type IV collagenases from Actinomadura atramentaria. III. Structure elucidation of matlystatins A to F.

The structures of matlystatins, novel type IV collagenase inhibitors isolated from Actinomadura atramentaria, have been determined by a systematic application of homo- and heteronuclear 2D NMR and FAB-MS/MS techniques. Their structures were characterized by the presence of piperazic acid and hydroxamic acid moieties, structural motifs often seen in protease inhibitors.

[A phase III trial of subcutaneous administration of rhG-CSF in the myelodysplastic syndromes].

To evaluate the safety and efficacy of subcutaneous administration of recombinant human granulocyte colony-stimulating factor in the myelodysplastic syndromes (MDS), 20 patients were given a daily dose of 50 micrograms/m2 of KRN8601 for 4 weeks. When the blood neutrophil count did not reach 2,000/microliters within 2 weeks, the dose was increased to 100 micrograms/m2. A marked neutrophilic response was obtained in 17 of the 18 evaluable patients (94.4%), irrespective of the MDS disease type. Five patients showed a platelet increase, 3 of which also showed an erythroid improvement. To maintain neutrophil levels greater than 1,000/microliters, 12 patients were treated with KRN8601 for 4 weeks. A dose of 25 to 50 micrograms/m2 3-4 times a week served to this end in 8 patients and 100 micrograms/m2 three times a week or daily in the remaining 4 patients. One patient with RAEB progressed to acute myeloid leukemia 8 weeks after KRN8601. The treatment was well-tolerated in the majority of patients with no severe toxicities. These results suggest that subcutaneous administration of KRN8601 is safe and useful in the treatment of cytopenias in MDS.