A new carboxylesterase from Brevibacterium linens IFO 12171 responsible for the conversion of 1,4-butanediol diacrylate to 4-hydroxybutyl acrylate: purification, characterization, gene cloning, and gene expression in Escherichia coli

A carboxylesterase that is responsible for conversion of 1,4-butanediol diacrylate (BDA) to 4-hydroxybutyl acrylate (4HBA) was found in Brevibacterium lines IFO 12171, and purified to homogeneity. The purified enzyme was active toward a variety of diesters of ethylene glycol, 1,4-butanediol, and 1,6-hexanediol. The K(m) and kcat of the enzyme for BDA were 3.04 mM and 203,000 s-1, respectively. The reaction with the purified enzyme gave 98 mM 4HBA from 100 mM BDA for 60 min. The enzyme gene was cloned from the chromosomal DNA of the bacterium. The open reading frame encoding the enzyme was 1176 bp long, corresponding to a protein of 393 amino acid residues (molecular mass = 42,569 Da). The deduced amino acid sequence contained the tetra peptide motif sequence, STTK, and the serine residue was confirmed to be the catalytic center of BDA esterase by site-directed mutagenesis for several amino acid residues. The gene was expressed in Escherichia coli under the control of the lac promoter, and the gene product (a fusion protein with 6 amino acid residues from beta-galactosidase) showed the same catalytic properties as the enzyme from the parent strain.

The effects of wrist distraction on carpal kinematics

Changes in carpal kinematics under wrist distraction were studied in fresh cadaveric specimens. A magnetic tracking device measured kinematic motions of the scaphoid, lunate, and third metacarpal relative to the fixed radius in 3 planes of passive motion (coronal, sagittal, and "dart throwers") under progressive distraction loads. The change in percent contribution of the radiocarpal and midcarpal joints was calculated. Radiocarpal motion during extension was decreased as increasing traction was applied, but it increased with flexion. Motion of the scaphoid relative to the lunate was smaller in the oblique plane, resulting in less radiocarpal motion than in the sagittal plane. In the coronal plane, traction had little effect on radial deviation, but ulnar angulation of the scaphoid was greater with ulnar deviation of the wrist. These results suggest that different degrees of tension exist in the palmar and dorsal ligaments with the wrist under traction and during different planes of wrist motion. If wrist motion is desired during fixed traction, such as used clinically with external fixation, the dart-throwers motion (wrist extension with radial deviation and wrist flexion with ulnar deviation) appears to have the least impact on radiocarpal motion. If greater radiocarpal motion is desired, however, such as during postoperative mobilization, flexion-extension and radioulnar deviation will create more radiocarpal motion than the dart-thrower's motion.

Enhanced growth of human vascular endothelial cells on negative ion (Ag-)-implanted hydrophobic surfaces

Silver negative ions (Ag-) were implanted to an insulator, polystyrene, in a relatively low ion energy ranging from 5 to 30 keV, and in a dose ranging from 10(14) to 6 x 10(16) ions. cm-2. Surfaces of Ag--implanted polystyrene were studied by means of secondary ion mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and micro-Raman spectroscopy, and contact angle measurement. As a result of Ag- implantation, the polystyrene surfaces underwent degradation, thereby becoming more hydrophilic with increasing dose and ion energy except an ion energy of 30 keV. The Ag- implantation in polystyrene led to enhanced growth of human vascular endothelial cells, which grew to more extent with increased hydrophilicity of Ag--implanted surfaces except an ion energy of 30 keV. Polystyrene surfaces on which Ag- were implanted up to an ion energy of 30 keV caused the same hydrophobic level as polystyrene surface itself. Nevertheless, the Ag--implanted polystyrene showed relatively good biocompatibility different from polystyrene. Such an improvement in cell adhesion may be related to the formation of a graphite-like structure on polystyrene surfaces by a Ag--implanted process. Moreover, upon plating in a high cell density, human vascular endothelial cells survived even on the polystyrene region of Ag--implanted polystyrene for longer than 1.5 months, while the cells did not grow on untreated polystyrene in the same culture conditions.

Effect of the interaction between fibronectin and VLA-4 on the proliferation of human B cells, especially a novel human B-cell line, OPM-3

Very late antigen (VLA)-4 integrin has been suggested to play an important role in haemopoiesis. However, little is known concerning the roles of the fibronectin (FN)/VLA-4 interaction in the proliferation of human B cells. In this study we investigated the effect of immobilized FN on the proliferation of various B-cell lines, including a newly-established B-cell line, OPM-3, and human tonsillar B cells, that primarily express VLA-4 but not VLA-5. Immobilized FN significantly promoted the proliferation of OPM-3 cells and normal B cells via VLA-4. The cross-linking of beta1 integrins of OPM-3 cells resulted in the phosphorylation of the focal adhesion kinase (FAK) associated 90 kD protein, an increase in FAK-associated kinase activity, and the phosphorylation of Raf-1. Furthermore, the MEK1 inhibitor, PD98059, inhibited the FN-promoted proliferation of OPM-3 cells. These results demonstrate that the FN/VLA-4 interaction transmits the growth signal(s) which may be mediated by Ras pathway in OPM-3 cells, and suggest that OPM-3 cells may be of great value in studying the roles of the FN/VLA-4 interaction in human B-cell growth.

Decreased nitric oxide-mediated natural killer cell activation in chronic fatigue syndrome

BACKGROUND

L-Arginine (L-Arg), one of the essential amino acids, has been reported to have an immunomodulatory effect. The precise mechanism of the L-Arg-induced natural killer (NK) cell activation remains unresolved,and the effect of L-Arg on NK cells in chronic fatigue syndrome (CFS) patients has not been estimated.

METHODS

NK cell function was evaluated in 20 subjects with CFS and compared with that in 21 healthy individuals.

RESULTS

In healthy control subjects, NK activity was significantly increased after treatment with L-Arg, an NK function enhancer, for 24 h, whereas the same treatment failed to enhance NK activity in the CFS patients. We thus focused on L-Arg metabolism, which involves nitric oxide (NO) production through NO synthase (NOS). The expression of inducible NO synthase (iNOS) transcripts in peripheral blood mononuclear cells was not significantly different between healthy control subjects and CFS patients. The L-Arg-mediated NK cell activation was abolished by addition of NG-monomethyl-L-arginine, an inhibitor for iNOS. Furthermore, incubation with S-nitroso-N-acetyl-penicillamine, an NO donor, stimulated NK activity in healthy control subjects but not in CFS patients.

CONCLUSION

These results demonstrate that the L-Arg-induced activation of NK activity is mediated by NO and that a possible dysfunction exists in the NO-mediated NK cell activation in CFS patients.

Insulin-like growth factor-I augments erythropoietin-induced proliferation through enhanced tyrosine phosphorylation of STAT5

Insulin-like growth factor (IGF-I) is known to synergistically stimulate the proliferation of hematopoietic cells in combination with other hematopoietic growth factors. However, the precise mechanism underlying the cooperative effects of IGF-I is unknown. In a human interleukin-3 or erythropoietin (EPO)-dependent cell line, F-36P, IGF-I alone failed to stimulate DNA synthesis but did augment the EPO-dependent DNA synthesis of F-36P cells. The treatment of F-36P cells with a combination of EPO and IGF-I (EPO/IGF-I) was found to enhance EPO-induced tyrosine phosphorylation of STAT5, whereas IGF-I alone did not. Furthermore, c-CIS mRNA expression, one of the target molecules of STAT5, was more effectively induced by EPO/IGF-I than by EPO alone. To examine the mechanisms of the EPO- and EPO/IGF-I-induced proliferation of F-36P cells, we expressed dominant negative (dn) mutants of STAT5 and Ras in an inducible system. The EPO-induced DNA synthesis and the cooperative effect of EPO/IGF-I were significantly inhibited by the inducible expression of dn-STAT5 or dn-Ras. In addition, the inducible expression of dn-Ras abolished the IGF-I-enhanced tyrosine phosphorylation of STAT5. These results suggest that IGF-I may augment EPO-induced proliferation by enhancing tyrosine phosphorylation of STAT5 and raise the possibility that Ras may be involved in the augmentation of STAT5 tyrosyl phosphorylation.

The novel enzymatic 3''-N-acetylation of arbekacin by an aminoglycoside 3-N-acetyltransferase of Streptomyces origin and the resulting activity

Kanamycin group antibiotics were subjected to enzymatic acetylation by a cell free extract containing an aminoglycoside 3-N-acetyltransferase, AAC(3)-X, derived from Streptomyces griseus SS-1198PR. Characterization of the incubated reaction mixtures by TLC and antibiotic assay revealed that a product retaining activity was specifically formed from arbekacin, an anti-MRSA semisynthetic aminoglycoside. The structural determination demonstrated that acetylation occurred at the 3"-amino group in arbekacin and amikacin, and at the 3-amino group in dibekacin as in the case of kanamycin. These results should reflected the effect of the (S)-4-amino-2-hydroxybutyryl side chain which is present in arbekacin and amikacin, but absent in dibekacin and kanamycin. The 3"-N-acetylation is the first finding in the enzymatic modifications of aminoglycoside antibiotics. 3"-N-Acetylarbekacin showed antibiotic activity as high as that of 2'-N-acetylarbekacin reported previously, whereas 3"-N-acetylamikacin showed no substantial activity. Thus, our results illuminated a novel aspect of arbekacin distinct from the other aminoglycosides.

A strategy for organ allografts without using immunosuppressants or irradiation

A strategy to achieve regular and long lasting organ and tissue allografts without using immunosuppressants and/or irradiation has been established for mice. One hundred percent of skin allografts can be induced to survive >350 days after transplantation if spleen cells from the same donors are first injected into the portal vein of the recipients. The mechanisms underlying this long-term tolerance induction can be described as follows: (i) donor T cells from the spleen of the donor facilitate the acceptance of the allogeneic engraftment, (ii) donor-specific anergy is induced in the cytotoxic T-lymphocytes of the recipients, (iii) T helper type 2 cells become the dominant T cells in the recipients that are accepting the skin transplants, and (iv) a lasting chimerism (microchimerism) is established in these recipients. This strategy, perhaps with minor modifications, might permit one also to overcome major barriers to organ allografting in humans. If this were the case, it could represent production of long lasting immunologic tolerance without need for irradiation or cytotoxic chemo-preparative regimen and as such could greatly facilitate allotransplantation free of episodes of chronic or acute rejection or toxic and damaging preparatory regimens.

Growth-supporting activities of fibronectin on hematopoietic stem/progenitor cells in vitro and in vivo: structural requirement for fibronectin activities of CS1 and cell-binding domains

Fibronectin (FN) is supposed to play important roles in various aspects of hematopoiesis through binding to very late antigen 4 (VLA4) and VLA5. However, effects of FN on hematopoietic stem cells are largely unknown. In an effort to determine if FN had a growth-supporting activity on hematopoietic stem cells, human CD34(+)/VLA4(bright)/VLA5(dull) hematopoietic stem cells and a murine stem cell factor (SCF)-dependent multipotent cell line, EML-C1, were treated with or without FN in a serum and growth-factor-deprived medium, and then subjected to clonogenic assay in the presence of hematopoietic growth factors. The pretreatment of the CD34(+) cells with FN gave rise to significantly increased numbers of granulocyte-macrophage colony-forming units (CFU-GM), erythroid burst colony-forming units, and mixed erythroid-myeloid colony-forming units. In addition, the numbers of blast colony-forming units and CFU-GM that developed after culture of EML-C1 cells with SCF and the combination of SCF and interleukin-3, respectively, were augmented by the pretreatment with FN. The augmented colony formation by FN was completely abrogated by the addition of CS1 fragment, but not of GRGDSP peptide, suggesting an essential role of FN-VLA4 interaction in the FN effects. Furthermore, the effects of various FN fragments consisting of RGDS-containing cell-binding domain (CBD), heparin-binding domain (HBD), and/or CS1 portion were tested on clonogenic growth of CD34(+) cells. Increased colony formation was induced by CBD-CS1 and CBD-HBD-CS1 fragments, but not with other fragments lacking CBD or CS1 domains, suggesting that both CS1 and CBD of FN were required for the augmentation of clonogenic growth of hematopoietic stem/progenitor cells in vitro. In addition to the in vitro effects, the in vivo administration of CBD-CS1 fragment into mice was found to increase the numbers of hematopoietic progenitor cells in bone marrow and spleen in a dose-dependent manner. Thus, FN may function on hematopoietic stem/progenitor cells as a growth-supporting factor in vitro and in vivo.

Hypoglycemic and hypotensive effects of 6-cyclohexyl-2'-O-methyl-adenosine, an adenosine A1 receptor agonist, in spontaneously hypertensive rat complicated with hyperglycemia

Metabolic and cardiovascular effects of 6-cyclohexyl-2'-O-methyl-adenosine (SDZ WAG 994), a selective and orally-active adenosine A1 receptor agonist, were examined in spontaneously hypertensive rats (SHR) with hyperglycemia (SHR-DM). This model was made by the administration of streptozotocin (STZ; 60 mg/kg s.c.) to SHR 2 days after their birth. The serum glucose concentration and systolic/mean blood pressures (MBP) in 18-22-week-old rats were 14.7 +/- 0.8 mmol/1 and 153 +/- 3/124 +/- 3 mmHg in SHR-DM, 13.7 +/- 0.3 mmol/1 and 123 +/- 3/96 +/- 4 mmHg in normotensive with STZ (WKY-DM), 10.3 +/- 0.3 mmol/1 and 165 +/- 1/136 +/- 3 mmHg in non-treated (without STZ) SHR, and 10.0 +/- 0.3 mmol/1 and 115 +/- 3/90 +/- 4 mmHg in non-treated WKY, SDZ WAG 994 at 0.1 mg/kg p.o. lowered the serum glucose concentration, blood pressure and heart rate in SHR-DM. The effects were associated with the decrease in free fatty acid (FFA), triglyceride (TG), phospholipid (PL) and total cholesterol (TC) in serum of both SHR-DM and WKY-DM. On the contrary, the hypoglycemic effect was not found in WKY-DM, although the hypotensive effect was still observed. These data suggest that the risk factors for metabolic and cardiovascular complications in diabetes are reduced by SDZ WAG 994 through activation of adenosine A1 receptors in adipocyte.

[Wide craniotomy-small dural incisions and intentionally delayed removal of intracerebral contusional hemorrhage for acute subdural hematoma]

The outcome of acute subdural hematoma (ASDH), which can cause severe parenchymal injury, has generally been unsatisfactory. The standard surgical procedure for ASDH is a quick and wide opening by dural incision, removal of the subdural and contusional intracerebral hematoma, followed by large external and internal decompression. In this study, we assessed our therapeutic strategy, consisting of three principles: 1. Removal of subdural hematoma by wide craniotomy-small dural incisions, in well-decompressed case, connecting the small dural incisions and stanching the bleeding points on the cortical surface but not proceeding with contusional hemorrhage in emergency operations, 2. Post-operative induction of mild barbiturate-moderate hypothermia therapy and 3. Intentionally delayed evacuation of the intracerebral contusional hemorrhage when needed. The patients, profile is composed of an old therapy group (27 cases) and a new therapy group (20 cases) suffering from ASDH with cerebral contusion. The clinical outcome with the old therapeutic strategy was good recovery (GR) in 7 cases, moderate disability (MD) in 5, severe disability (SD) in 2, vegetative state (PVS) in 3 and death (D) in 10, whereas the outcome with the new strategy resulted in GR in 15 cases, MD in 3, D in 2. These clinical results indicate that the rates of mortality and severe morbidity were markedly reduced with our new therapeutic strategy.

Feasibility of using a magnetic tracking device for measuring carpal kinematics

While several different methods have been used to measure carpal kinematics, biplanar radiography is generally considered to be the most accurate and popular one. However, biplanar radiography is tedious and so only pseudo-dynamic kinematics can be measured. Recently, magnetic tracking system has been developed for the measurement of joint kinematics which is versatile and easy to use and so the possibility of measuring motions dynamically. In this study, the capability of a magnetic tracking device to accurately measure carpal kinematics was investigated by comparing it with biplanar radiography. The kinematics of the third metacarpal, scaphoid, and lunate in five fresh cadaveric specimens were measured using both methods as the wrists were placed in eight positions. The finite screw rotation of each bone with respect to the distal radius during selecting the seven wrist motions was calculated for both measuring techniques and compared. In general, the kinematics for all three bones measured by using either magnetic tracking device or biplanar radiography was identical and showed no statistical difference. The averaged differences ranged from 0.0 to 2.0 degrees. These differences were due to the potential effect of the weight of the sensors and the interference of the attaching rod to the surrounding tissue. It is concluded that the application of the magnetic tracking device to carpal kinematics is warranted, if proper technical procedures as suggested are followed.

Genetic mutations of butyrylcholine esterase identified from phenotypic abnormalities in Japan

We have identified 12 kinds of genetic mutations of butyrylcholine esterase (BCHE) from phenotypic abnormalities, showing that BCHE activities were deficient or diminished in sera. These genetic mutations, detected by PCR-single-strand conformation polymorphism analysis and direct sequencing, consisted of one deletion (BCHE*FS4), nine missense (BCHE*24 M, *1005, *250P, *267R, *330I, *365R, *418S, *515C, *539T), and two nonsense mutations (BCHE*119STOP, *465STOP). All of the individuals deficient in serum BCHE activity were homozygous for silent genes (6 of 6). Fifty-eight percent of the individuals (31 of 53) with slightly reduced serum BCHE activity were heterozygous for silent genes. They also showed a higher frequency (47% as allele frequency) of the K-variant than the general population (17.5%). Finally, we confirmed low serum BCHE activity in 10 of 23 individuals heterozygous for silent genes.

[Analysis of mild barbiturate-moderate hypothermia therapy on the authors' 152 cases]

Mild barbiturate-moderate hypothermia therapy was established for severe head injury and cerebrovascular disease. This study was conducted on 152 patients from April 1984 through July 1995. In this study were included patients with Glagow Coma Scale score of less than 8 points but those with serious systemic complications and elderly and infantile patients were excluded. Our protocol consisted of administration of thiamylal Na 1.25-2.5 mg/kg/h and droperidol 20-40 micrograms/kg/h (mild barbiturate) while maintaining a core temperature of 32-34 degrees C (moderate hypothermia). The clinical outcome was good (GR, MD) in 58 cases, poor (SD) in 24 cases and bad (PVS, D) in 70 cases. This therapy was found to be particularly effective for preventing ischemic neurological damage in the vasospasm stage following SAH and severe head injury in young patients. However, this therapy did not prevent pneumonia, cardiac failure, arrhythmia and hypopotassemia from occurring frequently. We conclude that this therapy is contraindicated in the elderly, i.e., those older than 65 years.

Thrombopoietin-induced differentiation of a human megakaryoblastic leukemia cell line, CMK, involves transcriptional activation of p21(WAF1/Cip1) by STAT5

Although thrombopoietin (TPO) is known to play a fundamental role in both megakaryopoiesis and thrombopoiesis, the molecular mechanism of TPO-induced megakaryocytic differentiation is not known. In a human megakaryoblastic leukemia cell line, CMK, that showed some degree of megakaryocytic differentiation after culture with TPO, the cyclin-dependent kinase (Cdk) inhibitor p21(WAF1/Cip1), but not p27(Kip1), p16(INK4A), p15(INK4B), or p18(INK4C), was found to be upregulated in an immediately early response to TPO. The expression of p21 was found to be sustained over a period of 5 days by treatment with TPO in large polyploid cells that developed in response to TPO, but not in small undifferentiated cells, indicating a close correlation between the ligand-induced differentiation and p21 induction in CMK cells. To examine potential roles of Cdk inhibitors in megakaryocytic differentiation, CMK cells were transfected with the p21, p27, or p16 gene, together with a marker gene, beta-galactosidase, and were cultured with medium alone for 5 days. The ectopic expression of p21 or p27 but not of p16 led to induction of megakaryocytic differentiation of CMK cells. Overexpression of the N-terminal domain (amino acids [aa] 1 to 75) of p21 was sufficient to induce megakaryocytic differentiation, whereas that of the C-terminal domain (aa 76 to 164) had little or no effect on morphological features. Furthermore, we found that although TPO induced tyrosine phosphorylation of both STAT3 and STAT5 in CMK cells, only STAT5 showed binding activities to potential STAT-binding sites that locate in the promoter region of p21 gene (p21-SIE sites), thereby leading to transactivation of p21. These results suggested that p21 induction, possibly mediated through activated STAT5, could play an important role in TPO-induced megakaryocytic differentiation.

[A case of basilar impression treated with mandible splitting transoral approach]

We report a case of basilar impression treated with mandible splitting transoral approach surgery. A 39-year-old man presented a ten-year history of gait disturbance. He had experienced acceleration of his spastic paraparesis for the past few years. Neurological examination on admission demonstrated tetraparesis (MMT4/5), severe hyperreflexia in his arms and legs, severe sensory loss below C2, urinary retention and inability to open his mouth widely. Radiological findings showed the dens and the body of C2 are deeply invaginated to the atlas and the foramen magnum and medulla and upper cervical cord were markedly compressed by this basilar invagination. After carrying out posterior decompression and occipito-cervical fixation, we attempted to remove the invaginated dens and the C2 vertebral body using a conventional transoral approach. But limitation of mouth opening made operative fields narrow. Consequently because of insufficient anterior decompression his neurological deficits could not be alleviated. Employment of mandible splitting procedure brought about a wide operative view so that complete removal of the residual dens and 70% drilling out of the C2 body was made possible. Postoperative complications were negligible. Finally, great alleviation of his deficits was achieved. Mandible splitting procedure is effective for obtaining a wide operative field on the anterior approach to the craniocervical junction.

Boundary lubrication between the tendon and the pulley in the finger

The lubrication mechanism between the human flexor digitorum profundus tendon and the A2 pulley was investigated in vitro. The gliding resistance at the interface between the tendon and the pulley increased significantly after the tendon had been treated with a hyaluronidase solution. Alcian-blue staining of the surface of the tendon before and after it was treated with hyaluronidase suggested the presence of hyaluronate complex. Alcian blue-positive and hyaluronidase-sensitive materials, such as hyaluronate or proteoglycan, in the synovial membrane and the matrix of the tendon, may act as a boundary lubricant, facilitating the gliding and reducing the resistance between the tendon and the pulley.

Effect of YM934, a KATP channel opener, on airway hyperresponsiveness induced by platelet activating factor in guinea-pigs

The effect of YM934 (2-(3,4-dihydro-2,2-dimethyl-6-nitro-2H-1, 4-benzoxazin-4-yl)pyridine N-oxide) on airway hyperresponsiveness induced by platelet activating factor (PAF) was investigated in anesthetized guinea-pigs. Bronchoconstrictor responses to histamine were enhanced by intravenous (i.v.) infusion of PAF (600 ng/kg/h for 1 h). The KATP channel opener, YM934 (10-100 micrograms/ kg), given by i.v. bolus injection or i.v. infusion (75 min) dose-dependently inhibited this PAF-induced airway hyperresponsiveness. In the normal control group, i.v. bolus injection of YM934 dose-dependently reduced the bronchoconstrictor responses to histamine. However, i.v. infusion of YM934 (100 micrograms/kg) had almost no effect on responsiveness. Pretreatment with capsaicin (50 micrograms/kg, s.c.), a depleter of neuropeptides, partially prevented the development of PAF-induced airway hyperresponsiveness. In contrast, phosphoramidon (2.5 mg/kg, i.v.), an inhibitor of neutral endopeptidase, enhanced the airway hyperresponsiveness induced by PAF. Furthermore, YM934 inhibited PAF-induced airway hyperresponsiveness in guinea-pigs pretreated with capsaicin or phosphoramidon. The present results suggest that YM934 given by i.v. infusion reduces PAF-induced airway hyperresponsiveness at doses insufficient to produce a bronchodilatory effect. Further, the mechanism of YM934's inhibitory effect on airway hyperresponsiveness may involve bronchodilatory and other unidentified effects, such as a decrease in the release of neuropeptides from sensory nerve terminals.

Role of endogenous nitric oxide in airway microvascular leakage induced by inflammatory mediators

This study examines the role of endogenous nitric oxide (NO) in airway microvascular leakage induced inflammatory mediators, which play an important role in asthmatic airways. Guinea-pigs were anesthetized and mechanically-ventilated with monitoring of arterial blood pressure, and airway microvascular leakage induced by intravenous injection of substance P (SP), leukotriene D4 (LTD4) and histamine was evaluated using Evans blue dye and Monastral blue dye in the presence and absence of the NO synthase inhibitors, L-NG-nitroarginine methyl ester (L-NAME) and L-NG-monomethyl arginine (L-NMMA). The effect of a soluble guanylate cyclase inhibitor, LY83583, on SP-induced dye leakage was also examined. Intravenous injection of SP (1 microgram.kg-1), LTD4 (1 microgram.kg-1) and histamine (100 micrograms.kg-1) significantly increased dye extravasation at all airway levels. Pretreatment with L-NAME (10 mg.kg-1 i.v.) and L-NMMA (100 mg.kg-1 i.v.) significantly inhibited SP-induced extravasation, and L-arginine (100 mg.kg-1 i.v.) reversed L-NAME-induced inhibition. L-NAME (10 mg.kg-1 i.v.) also significantly inhibited LTD4-induced dye extravasation only in central airways, and this inhibitory effect was abolished by a neurokinin-1 (NK1) antagonist, FK888 (10 mg.kg-1 i.v.) pretreatment. Histamine-induced dye extravasation was not affected by L-NAME. LY83583 (2.5 and 7.5 mg.kg-1 i.v.) partially but significantly reduced SP-induced dye leakage. These results suggest that endogenous nitric oxide plays a role in neurokinin-1 receptor-mediated airway microvascular leakage, and presumably involves the guanylate cyclase pathway.

Construction of pRES18 and pRES19, Streptomyces-Escherichia coli shuttle vectors carrying multiple cloning sites

We developed two Streptomyces-Escherichia coli shuttle vectors. The plasmid pRES102, consisting of the essential region of pRES1 and the thiostrepton resistance gene (tsr) fragment of pIJ702, was combined with the E. coli plasmid vector pUC18 or pUC19. The resulting shuttle vectors, designated pRES18 and pRES19, respectively, have relatively compact size (6.25 kb), low copy number, multiple cloning sites reciprocally arranged in opposite directions, and selection markers for both Streptomyces (tsr) and E. coli (beta-lactamase (bla) and beta-galactosidase (lacZ). These shuttle vectors are capable of carrying DNA fragments as long as 10 kb, of being maintained in S. griseus, S. lavendulae and S. lividans, and are compatible with pIJ702.

Inhibitory effect of fluvastatin at doses insufficient to lower serum lipids on the catheter-induced thickening of intima in rabbit femoral artery

The anti-atherosclerotic effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors at doses insufficient to lower serum cholesterol was investigated in rabbit femoral artery denuded by balloon catheter. Fluvastatin and pravastatin were given orally at doses of 4 and 8 mg/kg per day, respectively, for 2 weeks after the catheterization. There was little change in serum cholesterol, triglyceride and phospholipid by chronic treatment with the drugs. The cross-sectional area of the intima, expressed as relative values to media (I/M ratio), was increased by the catheterization, showing intimal thickening in the denuded arteries. The I/M ratio was reduced by fluvastatin but not pravastatin: 0.327 +/- 0.060 for control, 0.116 +/- 0.035 for 4 mg/kg fluvastatin, 0.088 +/- 0.027 for 8 mg/kg fluvastatin and 0.22 +/- 0.069 for 8 mg/kg pravastatin. Fluvastatin (8 mg/kg)-induced effect on the I/M ratio, was prevented by the combined administration with 40 mg/kg per day mevalonate, a metabolite in the HMG-CoA reductase pathway. These results suggest that fluvastatin inhibits intimal thickening after catheterization-induced injury through percutaneous transluminal coronary angioplasty (PTCA) and that the inhibition is presumably attributed to reduced migration and proliferation of smooth muscle cells but not secondarily to a lowering of serum lipid.

Inhibitory effects of fluvastatin, a new HMG-CoA reductase inhibitor, on the increase in vascular ACE activity in cholesterol-fed rabbits

1. The effects of fluvastatin, a new 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on the vascular angiotensin converting enzyme (ACE) activity in hyperlipidaemic rabbits were compared with those of enalapril, an ACE inhibitor. 2. Rabbits were fed a 1.5% cholesterol containing diet or normal diet for 16 weeks and treated with either fluvastatin or enalapril in the diet at the respective doses of 2 and 10 mg kg-1 day-1. The total cholesterol, triglyceride and phospholipid levels in serum were significantly increased in rabbits fed the high cholesterol diet. Treatment with fluvastatin but not enalapril resulted in a decrease in serum lipids. 3. The vascular ACE activities assessed via the cleavage rate from synthetic substrate in the aortic arches and upper thoracic aortae were increased by 8 to 10 times when the rabbits were made hyperlipidaemic. Fluvastatin as well as enalapril significantly lowered the tissue ACE in the aortae. 4. The ACE activities in serum did not alter in hyperlipidaemic rabbits either in the presence or absence of fluvastatin. The serum ACE activity was lowered by enalapril. 5. The lipid peroxide in serum as well as the plaque area in the thoracic aorta was significantly increased in the cholesterol diet-fed rabbits. Treatment with fluvastatin or enalapril reduced both serum lipid peroxide and plaque formation. The relaxant responses to acetylcoholine (ACh) were significantly suppressed in the cholesterol-fed rabbits. Treatment with fluvastatin or enalapril significantly reversed the suppression of ACh-induced relaxation. 6. It seems that the reduction of vascular ACE is not coupled to lipids and ACE activity in serum, but rather to lipid peroxidation. Thus, the decrease in vascular ACE activity by fluvastatin as well as the lipid-lowering effect may reduce the risk of atherosclerosis progression in the vasculature.

The biologic properties of recombinant human thrombopoietin in the proliferation and megakaryocytic differentiation of acute myeloblastic leukemia cells

Thrombopoietin (TPO) is implicated as a primary regulator of megakaryopoiesis and thrombopoiesis. However, the biologic effects of TPO on human acute myeloblastic leukemia (AML) cells are largely unknown. To determine if recombinant human (rh) TPO has proliferation-supporting and differentiation-inducing activities in AML cells, 15 cases of AML cells that were exclusively composed of undifferentiated leukemia cells and showed growth response to rhTPO in a short-term culture (72 hours) were subjected to long-term suspension culture with or without rhTPO. Of 15 cases, rhTPO supported proliferation of AML cells for 2 to 4 weeks in 4 cases whose French-American-British subtypes were M0, M2, M4, and M7, respectively. In addition to the proliferation-supporting activity, rhTPO was found to induce AML cells to progress to some degree of megakaryocytic differentiation at both morphologic and surface-phenotypic level in 2 AML cases with M0 and M7 subtypes. The treatment of AML cells with rhTPO resulted in rapid tyrosine phosphorylation of the TPO-receptor, c-mpl, and STAT3 in all of cases tested. By contrast, the expression of erythroid/megakaryocyte-specific transcription factors (GATA-1, GATA-2, and NF-E2) was markedly induced or enhanced in only 2 AML cases that showed megakaryocytic differentiation in response to rhTPO. These results suggested that, at least in a fraction of AML cases, TPO could not only support the proliferation of AML cells irrespective of AML subtypes, but could also induce megakaryocytic differentiation, possibly through activation of GATA-1, GATA-2, and NF-E2.

Effect of YM934, a novel potassium-channel opener, in various experimental asthma models in guinea-pigs

YM934 is a novel synthetic potassium-channel opener. We have investigated its anti-asthma effect after intravenous (i.v.) and oral (p.o.) administration in various experimental asthma models in the guinea-pig, and compared the results with those for lemakalim, theophylline and salbutamol. In an ovalbumin-active sensitization anaphylaxis asthma model, YM934, lemakalim, theophylline and salbutamol dose-dependently prolonged the time before the occurrence of asthma attacks and reduced the mortality rate. The respective ED50 values (dose required to prolong by 50% the time before the occurrence of attacks) of the anti-asthma effects of YM934, lemakalim, theophylline and salbutamol were 6, 340, 30000, and 45 micrograms kg-1 (i.v.); the efficacy ratios were YM934 (1) > salbutamol (1/9) > lemakalim (1/57) > > theophylline (1/5000). YM934 also prolonged the period before the occurrence of attacks in the anti-BSA (bovine serum albumin) serum-passive sensitization anaphylaxis, histamine-induced and methacho-line-induced asthma models, with respective ED50 values for these models of 15, 22 and 20 micrograms kg-1 (i.v.). Among these models a reduction in mortality rate was seen in the histamine- and methacholine-induced asthma models. After oral administration, YM934 showed an anti-asthma effect in the ovalbumin-active sensitization anaphylaxis, histamine-induced and methacholine-induced asthma models, with respective ED50 values of 38, 44 and 193 micrograms kg-1. YM934 was 5-6 times more potent than salbutamol. These results indicate that YM934 has potent anti-asthma activity, and that this activity is mainly attributable to bronchodilation, most likely mediated through its potassium-channel opening activity.