Functional analysis of the cytoplasmic domain of the human Mpl receptor for tyrosine-phosphorylation of the signaling molecules, proliferation and differentiation

To investigate the functional domains for signal transduction of human Mpl, we constructed a series of human c-mpl cDNAs with various deletions in the cytoplasmic domain, and then introduced each cDNA into murine IL-3-dependent myeloid leukemia FDC/P2 cells to establish stable transformants. We examined the growth and differentiation responses and tyrosine phosphorylation of the intracellular signaling proteins including Jak2, Tyk2, Stat3, Stat5, Vav, SHPTP2, Cbl, Shc and Shc-associated p145 when receptor stimulation occurred after thrombopoietin (TPO) binding. TPO stimulated cell proliferation and induced the expression of megakaryocyte lineage-specific AP-51 and CD61 cell surface antigens and tyrosine phosphorylation of the signaling proteins in transformants expressing full length human Mpl. These results suggested that Mpl not only induced proliferation but also transduced megakaryocyte-specific differentiation signals into FDC/P2 cells. Mutational analysis of human Mpl indicated that the N-terminal region of its cytoplasmic domain is necessary and sufficient to transduce proliferation and differentiation signals into cells, while the C-terminal region may also play important roles in transducing the differentiation signals.

Interstitial duplication 8q22-q24: report of a case proven by FISH with mapped cosmid probes

We report on a 6-month-old malformed female infant with a de novo interstitial duplication of an 8q22-q24 segment. She had an excess dark-band on the 8q distal region by GTG-banded chromosome analysis, which was likely to be 8q23. We performed FISH analysis using cosmid probes mapped to 8q23 and proved that the patient had an 8q duplication including the 8q23 region.

An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5 (ref. 2), a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome, a cancer-predisposing syndrome, making it a tumour-suppressor candidate. Several types of childhood tumours including Wilms' tumour, adrenocortical carcinoma and rhabdomyosarcoma exhibit a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting is involved. Genetic analysis of the Beckwith-Wiedemann syndrome indicated maternal carriers, as well as suggesting a role of genomic imprinting. Previously, we and others demonstrated that p57KIP2 is imprinted and that only the maternal allele is expressed in both mice and humans. Here we describe p57KIP2 mutations in patients with Beckwith-Wiedemann syndrome. Among nine patients we examined, two were heterozygous for different mutations in this gene-a missense mutation in the Cdk inhibitory domain resulting in loss of most of the protein, and a frameshift resulting in disruption of the QT domain. The missense mutation was transmitted from the patient's carrier mother, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. Consequently, little or no active p57KIP2 should exist and this probably causes the overgrowth in this BWS patient.

Granulocyte-colony stimulating factor and stem cell factor are the crucial factors in long-term culture of human primitive hematopoietic cells supported by a murine stromal cell line

The findings that murine marrow stromal cell line MS-5 supported the proliferation of human lineage-negative (Lin-) CD34+CD38- bone marrow cells in long-term culture have been reported. In this study, we analyzed this proliferating activity of MS-5-conditioned medium (CM) on human primitive hematopoietic cells. When Lin-CD34+CD38- cells of normal human cord blood cells were co-cultured with MS-5, colony forming cells (CFCs) were maintained over 7 weeks in vitro. Prevention of contact between MS-5 and Lin-CD34+CD38- cells by using membrane filter (0.45 micron) was negligible for this activity. This indicated that the activity of MS-5 on human primitive hematopoietic cells is a soluble factor(s) secreted from MS-5, which is not induced by the contact between MS-5 and Lin-CD34+CD38- cells. We tried to purify this soluble activity. An active material with a molecular weight of about 150 kDa, determined by gel filtration chromatography, solely supported the growth of Lin-CD34+CD38- cells and Mo7e, a human megakaryocytic cell line. This activity not only reacted with anti-mouse stem cell factor (mSCF) antibody on Western blots, but it was also neutralized in the presence of anti-mSCF antibody. Another active material with a molecular weight of about 20-30 kDa synergized with mSCF to stimulate the growth of Lin-CD34+CD38- cells but failed to do so alone, although this synergy was inhibited in the presence of soluble mouse granulocyte-colony stimulating factor (mG-CSF) receptor, which is a chimeric protein consisting of the extracellular domain of mG-CSF receptor and the Fe region of human IgG1. In addition, the latter molecule supported the growth of the G-CSF dependent cell line FD/GR3, which is a murine myeloid leukemia cell line, FDC-P2, transfected with mG-CSF receptor cDNA. Adding of anti-mSCF antibody and soluble mG-CSF receptor to the culture completely abrogated the activity of MS-5-CM. Recombinant (r) mSCF and rmG-CSF had synergistic activity on the growth of Lin-CD34+CD38- cells. These results indicated that the activity on Lin-CD34+CD38- cells included in MS-5-CM is based upon the synergistic effects of mSCF and mG-CSF.

Some evidence against the involvement of arachidonic acid in muscarinic suppression of voltage-gated calcium channel current in guinea-pig ileal smooth muscle cells

1. To see if arachidonic acid (AA) plays a role in the sustained suppression of voltage-gated calcium channel currents produced by muscarinic receptor stimulation by carbachol (CCh), the effects of AA on membrane currents were examined in whole-cell voltage-clamped smooth muscle cells of the guinea-pig ileum. 2. In cells bathed in Ba2+ PSS and dialysed with Cs(+)-based low EGTA (0.05 mM) pipette solution, and in which Ba2+ current (IBa) flowing through voltage-gated calcium channels was evoked repeatedly by stepping to 0 mV from the holding potential of -60 mV, AA (1-30 microM), applied extracellularly, gradually suppressed IBa in a concentration-dependent manner. The IBa suppression was observed even with 20 mM EGTA in the pipette. 3. AA (3 microM) and CCh (10 microM) shifted the voltage-dependent inactivation curve of IBa in the negative potential direction, but the effect of AA differed from that of CCh in that an accompanying appreciable decrease in the slope was observed. 4. The sustained suppression of IBa induced by CCh (10 microM) remained almost unaltered after pretreatment with 4-bromophenacyl bromide (10 microM), an inhibitor of phospholipase A2, or a combination of indomethacin (10 microM), an inhibitor of the cyclo-oxygenase pathway, and nordihydroguaiaretic acid (10 microM), an inhibitor of the lipoxygenase pathway. 5. In cells bathed in Ca2+ PSS and dialysed with K(+)-based pCa 6.5 pipette solution, voltage-dependent Ca2+ current (ICa) and K+ current (IK) were recorded simultaneously. AA (3 microM) suppressed IK as well as ICa, whereas CCh (10 microM) suppressed ICa but not IK. 6. We conclude from these results that AA or its metabolite is unlikely to be involved in the sustained suppression of voltage-gated calcium channel current induced by muscarinic receptor stimulation in guinea-pig ileal smooth muscle cells.

Effect of recombinant human thrombopoietin in nonhuman primates with chemotherapy-induced thrombocytopenia

We examined the effects of recombinant human thrombopoietin (rhTPO) on myelosuppressive chemotherapy-induced thrombocytopenia in cynomolgus monkeys. After treatment with nimustine (ACNU) on day 0, the monkeys intravenously received rhTPO at a dose of 0.04, 0.2 or 1 microgram/kg/d or monkey's serum once each day from day 1 to day 28. Administration of rhTPO reduced the severity of thrombocytopenia and accelerated the rate of platelet recovery in a dose-dependent fashion. Treatment with the highest rhTPO dose completely prevented thrombocytopenia and stimulated a marked increase in platelet counts over the normal values. Animals treated with ACNU also became neutropenic and slightly anaemic. Administration of rhTPO following ACNU treatment significantly improved neutropenia with increasing doses of rhTPO, but had no effect on anaemia. Compared to the control animals, rhTPO-treated animals exhibited no significant changes in several serum parameters. C-reactive protein concentration and some blood coagulation profiles within the study period. These results suggest a therapeutic efficacy of rhTPO in improving chemotherapy-induced thrombocytopenia.

Modulation of carbachol-induced [Ca2+]i oscillations by Ca2+ influx in single intestinal smooth muscle cells

1. Oscillations of cytosolic Ca2+ concentration ([Ca2+]i) evoked by carbachol (CCh; 2 microM), a muscarinic agonist, were detected as oscillatory changes of muscarinic receptor-coupled cationic current (Icat) in guinea-pig ileal smooth muscle cells by the whole cell patch-clamp technique. 2. Reduction of extracellular Ca2+ from 2 mM to 0.2 or 0.05 mM, during CCh-induced Icat oscillations, caused them to disappear or to decrease markedly in frequency. A return to 2 mM Ca2+ concentration restored the initial Icat oscillations. 3. Application of nifedipine (1-3 microM) or D600 (2-5 microM) to block the voltage-gated Ca2+ channel (VGCC) decreased the frequency of the ongoing Icat oscillations in the cells held at -20 mV, but it was without effect in cells held at -60 mV. 4. Displacement of the holding potential of -20 mV to -60 mV to deactivate VGCC produced a decrease, an increase or no noticeable change in the frequency of the Icat oscillations in different cells. Displacement to 20 mV to inactivate VGCC invariably produced a decrease in the frequency. In nifedipine-treated cells, the Icat oscillations varied in frequency voltage-dependently in a reverse and linear way within the range -80 to 40 mV. 5. Application of thapsigargin (1 or 2 microM), an inhibitor of Ca(2+)-ATPase in the membrane of internal Ca2+ stores, caused CCh-induced Icat oscillations to disappear with a progressing phase during which their amplitude, but not frequency, declined. 6. The results suggest that membrane Ca2+ entry has a crucial role to play in regulation of the frequency of CCh-induced [Ca2+]i oscillations in addition to persistence of their generation, and that the effect is brought about by a potential mechanism independent of Ca2+ store replenishment. They also provide evidence that two types of Ca2+ permeant channels, VGCC and an as yet unidentified channel, are involved in the Ca2+ entry responsible for modulation of [Ca2+]i oscillations.

p120c-cbl is present in human blood platelets and is differentially involved in signaling by thrombopoietin and thrombin

To investigate the signaling processes induced by recombinant thrombopoietin, we used human platelets to recently show that thrombopoietin induces rapid tyrosine phosphorylation of Jak2, Tyk2, Shc, Stat3, Stat5, and other proteins in human platelets. Because the apparent molecular weight of a major tyrosine-phosphorylated protein in platelets stimulated by thrombopoietin is approximately 120 kD, we examined the possibility that this could be p120c-cbl, a protein known to be involved in signaling by many growth factors. Specific antisera against p120c-cbl recognized the same 120-kD protein in lysates of Jurkat cells, which are known to express p120c-cbl, and platelets, indicating that platelets have p120c-cbl. Thrombopoietin induced rapid tyrosine phosphorylation of p120c-cbl in platelets. Thrombopoietin also induced tyrosine phosphorylation of p120c-cbl in FDCP cells genetically engineered to express the thrombopoietin receptor, c-Mpl. Interestingly, FDCP cells, expressing a truncated c-Mpl devoid of the box-2 domain, proliferate in response to thrombopoietin. However, no increase in tyrosine phosphorylation of p120c-cbl was observed upon treatment of these cells with thrombopoietin, indicating that in this system tyrosine phosphorylation of p120c-cbl may not be essential for cell proliferation. This suggests that tyrosine phosphorylation of p120c-cbl may be required for nonmitogenic responses induced by thrombopoietin in postmitotic cells such as platelets. On the other hand, p120c-cbl was not significantly tyrosine-phosphorylated upon treatment of platelets with thrombin. However, it became incorporated into the Triton X-100-insoluble, 10,000g-sedimentable residue in an aggregation-dependent manner, suggesting that it may have a regulatory role in platelet cytoskeletal processes. p120c-cbl was constitutively associated with a 28-kD adapter protein, Grb2, that was also incorporated into the Triton X-100-insoluble, sedimentable residue dependent on aggregation. Further, we found that p120c-cbl is an endogenous substrate for calpain, a protease that may play a role in postaggregation signaling processes. Our data suggest that p120c-cbl may be involved in signal transduction following ligand binding to c-Mpl through its inducible tyrosine phosphorylation, and it may also be involved in signaling during platelet aggregation by its redistribution to the cytoskeleton.

Effects of lipid administration on lymphatic apolipoprotein A-IV and B output and synthesis

We examined the mesenteric lymphatic and portal venous transport of triglyceride (TG), free fatty acids (FFA), apolipoproteins (apo)A-IV and B in response to a bolus duodenal infusion of a TG-free control solution, and long-chain (18:1) and medium-chain (8:0) TG (LCT and MCT, respectively) emulsions in the rat. Additionally, intestinal and hepatic apo A-IV and apo B mRNA levels were also measured. Lymph apo A-IV, apo B (B-48), FFA, and TG output increased after LCT infusion, whereas only apo A-IV and FFA outputs increased after MCT infusion. On the other hand, portal FFA and apo A-IV transports increased at 15 min after MCT infusion but not after LCT infusion. Portal TG and apo B transports were not altered by either MCT or LCT infusion. Jejunal apo A-IV mRNA was increased after both MCT and LCT infusions. Hepatic apo A-IV mRNA levels increased only after MCT infusion. Conversely, neither LCT nor MCT had any effect on apo B mRNA levels in intestine or liver. These results indicate that apo A-IV is regulated by MCT absorption and that fatty acid reesterification and lipoprotein assembly are not prerequisite for such regulation. Conversely, it is likely that apo B-48 participates only in the formation and/or transport of chylomicrons after LCT absorption.

PRL-1, a protein tyrosine phosphatase, is expressed in neurons and oligodendrocytes in the brain and induced in the cerebral cortex following transient forebrain ischemia

Protein tyrosine phosphorylation is thought to play an important role in the regulation of neural function. We reported previously that CL100, a cytoplasmic type protein tyrosine phosphatase (PTP), was induced after transient forebrain ischemia. In the present study, changes in the mRNA levels after ischemia of PRL-1, a cytoplasmic type PTP and immediate-early gene similar to CL100, was examined. In situ hybridization histochemistry showed that PRL-1 mRNA was expressed in normal adult rats in neurons and oligodendrocytes in widespread regions including the cerebral cortex, hippocampus and cerebellum. PRL-1 mRNA was expressed in the developing brains on embryonic days 15 and 19 and postnatal day 1. Northern blot analysis showed that PRL-1 mRNA was induced from 6 h to 9 h after reperfusion in the cerebral cortex of postischemic rats. These findings suggest that PRL-1 plays a role in neurons and oliogodendrocytes, and that expression of PRL-1 mRNA is regulated by a mechanism different from those of other immediate-early genes such as c-fos and c-jun.

GpIIb/IIIa+ subpopulation of rat megakaryocyte progenitor cells exhibits high responsiveness to human thrombopoietin

The recently cloned factor thrombopoietin (TPO) has been shown to exhibit megakaryocyte colony-stimulating activity in vitro. In this investigation, to further evaluate the action of TPO on megakaryocyte progenitor cells (colony-forming units-megakaryocyte [CFU-MK]), GpIIb/IIIa+ and GpIIb/IIIa- populations of CFU-MK were prepared from rat bone marrow cells based on their reactivity with P55 antibody, a monoclonal antibody against rat GpIIb/IIIa, and their responsiveness to recombinant human TPO (rhTPO) and recombinant rat interleukin-3 (rrIL-3) was examined using a megakaryocyte colony-forming assay (Meg-CSA). rhTPO supported only megakaryocyte colony growth from both fractions in a dose-dependent fashion. The mean colony size observed with the GpIIb/IIIa+ population was smaller than that seen with the GpIIb/IIIa- population. With the optimal concentration of either rhTPO or rrIL-3, similar numbers of megakaryocyte colonies were formed from the GpIIb/IIIa+ population previously shown to be highly enriched for CFU-MK. In contrast, the maximum number of megakaryocyte colonies from the GpIIb/IIIa- population stimulated by rhTPO was only 24.2% of that achieved with rrIL-3. Morphologic analysis of rhTPO-promoted megakaryocyte colonies from the GpIIb/IIIa+ population showed that the average colony size was smaller but that the mean diameter of individual megakaryocytes was larger than in megakaryocyte colonies promoted with rrIL-3. rhTPO plus rrIL-3, each at suboptimal concentrations, had an additive effect on proliferation of CFU-MK in the GpIIb/IIIa+ fraction, whereas rhTPO plus murine IL-6 or murine granulocyte-macrophage colony-stimulating factor (mG-M-CSF) modestly but significantly reduced megakaryocyte colony growth. These results indicate that TPO preferentially acts on GpIIb/IIIa+ late CFU-MK with lower proliferative capacity and interacts with some other cytokines in CFU-MK development.

Increased production of B cell growth factor (BCGF) in Sjögren's syndrome

The objective of this investigation to clarify possible roles of B cell growth factor (BCGF) in the abnormal activation of B cells in Sjögren's syndrome (SS). Lymphocyte subsets of peripheral blood from 20 patients with SS (14 with primary SS and six with secondary SS) and 11 healthy donors were analysed by flow cytometry. Supernatants of peripheral blood T cells obtained from patients with SS and from donors, cultured with or without PHA, were studied using bioassay with a B cell line, KS-3.F10. The number of CD20+ cells and CD4+DR+ cells was significantly increased in SS patients compared with healthy donors. T cells from SS patients showed increased production of BCGF, whether or not they were stimulated with PHA. The enhancement of BCGF production by PHA had a positive correlation with the percentage of CD4+CD45RA+ cells, and a negative correlation with the focus score of lip biopsy. Our experiments showed that BCGF production by T cells was spontaneously increased in SS patients. The accelerated BCGF production with PHA stimulation may be related to the increase of CD4+CD45RA+ cells and the decrease of the inflammation determined by the grade of cell infiltration into salivary glands, but not by the increase of CD20+ cells.

Diagnosis of four chromosome abnormalities of unknown origin by chromosome microdissection and subsequent reverse and forward painting

A molecular cytogenetic method consisting of chromosome microdissection and subsequent reverse/forward chromosome painting is a powerful tool to identify chromosome abnormalities of unknown origin. We present 4 cases of chromosome structural abnormalities whose origins were ascertained by this method. In one MCA/MR patient with an add(5q)chromosome, fluorescence in situ hybridization (FISH), using probes generated from a microdissected additional segment of the add(5q) chromosome and then from a distal region of normal chromosome 5, confirmed that the patient had a tandem duplication for a 5q35-qter segment. Similarly, we ascertained that an additional segment of an add(3p) chromosome in another MCA/MR patient had been derived from a 7q32-qter segment. In a woman with a history of successive spontaneous abortions and with a minute marker chromosome, painting using microdissected probes from the whole marker chromosome revealed that it was i(15)(p10) or psu dic(15;15)(q11;q11). Likewise, a marker observed in a fetus was a ring chromosome derived from the paracentromeric region of chromosome 19. We emphasize the value of the microdissection-based chromosome painting method in the identification of unknown chromosomes, especially for marker chromosomes. The method may contribute to a collection of data among patients with similar or identical chromosome abnormalities, which may lead to a better clinical syndrome delineation.

A sensitive sandwich ELISA for measuring thrombopoietin in human serum: serum thrombopoietin levels in healthy volunteers and in patients with haemopoietic disorders

A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) has been established to estimate serum thrombopoietin (TPO) concentrations in healthy volunteers and patients with haemopoietic disorders. The ELISA uses a mouse monoclonal antibody (Ab) as the capture Ab and a biotinylated rabbit polyclonal Ab as the detector. The ELISA was reproducible, highly sensitive and specific for human TPO. The coefficients of intra-and inter assay variation were from 3.0% to 4.9% and from 5.9% to 6.1%, respectively. The quantitative limit of the ELISA was 0.09 fmol/ml in serum. The quantitative limit was lower than the normal level. The dose-response curves of serum samples from healthy volunteers and patients with haemopoietic disorders were parallel to the standard curves. The ELISA did not cross-react with a variety of blood components and cytokines to produce false-positive results. The serum TPO concentrations from 29 normal males and 21 females were 0.79 +/- 0.35 and 0.70 +/- 0.26 fmol/ml, respectively. Serum TPO levels in patients with aplastic anaemia (AA), acute lymphocytic leukemia (ALL) and essential thrombocythaemia (ET) were measured using the ELISA. The serum TPO levels in the patients with ET (n = 6, 2.80 +/- 1.55 fmol/ml) were higher than the normal level. The patients with AA (n = 7, 18.53 +/- 12.37 fmol/ml) and ALL (n = 5, 10.36 +/- 5.57 fmol/ml) had significantly higher serum TPO levels than normal individuals. These results indicate that the ELISA specific to TPO should prove useful in measuring the TPO concentration in serum samples.

Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57KIP2 is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor suppressor candidate. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. Genetic analysis of the familial BWS has indicated maternal carriers and suggested a role in genomic imprinting. Previously, we demonstrated that p57KIP2 is imprinted in the mouse. Here we describe the genomic imprinting of human p57KIP2 and the reduction of its expression in Wilms' tumors. High resolution mapping locates p57KIP2 in the region responsible for both tumor suppressivity and BWS.

The role of physicochemical properties of biomaterials and bacterial cell adhesion in vitro

This study was undertaken to investigate the physicochemical aspects of the interaction between the surface of biomaterials and bacterial cell membranes in vitro, aimed at studying the mechanisms of bacterial adhesion to biomaterials. Correlations were made between the number of adherent bacterial cells (S. aureus) and each of the calculated components of surface free energy (i.e., dispersion, polarity and hydrogen bond) of biomaterials. The effect of antibodies to cell-adhesion molecules on bacterial adhesion was also studied using monoclonal antibodies to vitronectin receptor, fibronectin receptor and CD44. This study indicates the polarity component of surface free energy plays a dominant role in the process of bacterial adhesion at least in vitro. The number of cells adherent to materials decreased to 44-73% of the control value in the presence of antibodies tested, showing that cell adhesion molecules affect adherence to biomaterials. Moreover, the results suggested that bacterial adhesion was prevented by specific blockade of cell adhesion molecule receptors.

[Coronary artery bypass grafting for acute myocardial infarction]

Five hundred and fourteen cases with acute myocardial infarction were admitted to our hospital during the past 5 years, since April 1990. Among 343 cases who had emergency coronary angiography, 53 cases had coronary artery bypass grafting surgery within 2 weeks after the onset of acute myocardial infarction. Mean number of bypass grafts was 2.9 +/- 0.9/patient, and operative mortality was 25% (13/53). Clinical condition immediately before the surgery and surgical mortality was, shock state in 20 cases (mortality 50%), IABP dependent state in 23 cases (mortality 13%), post-infarction angina in 8 cases (mortality 0%). Mortality in 8 cases whose infarct-related artery was left main trunk was as high as 63%. Eight of 9 cases whose cardiac indices were below 2.01/min/m2 immediately after the surgery died of pump failure. On the contrary, only 2 of 37 cases whose post-operative cardiac indices were above 2.01/min/m2 died of non-cardiac reason. To improve the surgical results, we concluded that powerful mechanical support such as ventricular assist system should be applied to post-operative pump failure cases whose cardiac indices were below this limit despite the aid of IABP.

Production of recombinant human monoclonal antibody using ras-amplified BHK-21 cells in a protein-free medium

A ras oncogene-amplified recombinant BHK-21 cell line (ras-rBHK-IgG) has been established, and was shown to hyperproduce the recombinant IgG chimeric human monoclonal antibody (hMAb) AE6F4, which recognizes lung cancer cells. We found that the ras-rBHK-IgG cell could be easily cultured in a protein-free ERDF medium supplemented with iron(III) nitrate, hydroxyethyliminodiacetic acid, and non-protein synthetic attachment factor as well as in a serum-free ERDF medium supplemented with insulin, transferrin, ethanolamine, and sodium selenite. The productivity of recombinant hMAb from the cells cultured in dishes at high cell densities was higher in protein-free medium than in serum-containing medium. True high density culture of the ras-rBHK-IgG cells was done in protein-free medium using the Tecnomouse, which is a novel hollow fiber bioreactor system. After culture for 30 days in protein-free culture, a total amount of about 14 mg of the recombinant hMAb AE6F4 was obtained, and was shown to be reactive against lung cancer cells in tissues.

Modulation of peristalsis by neurotensin in isolated guinea-pig intestinal segments

Neurotensin (1-100 nM) produced an inhibitory effect and an excitatory effect on the peristaltic activity elicited by intraluminal distension using the Trendelenburg method or the intraluminal perfusion method in isolated segments of guinea-pig small intestine. The relative contribution of these effects to the overall effect varied from one region to another of the small intestine. In the Trendelenburg preparation, the excitatory effect was found to be accompanied by a decrease in the threshold intraluminal pressure required to trigger a peristaltic reflex. A substantial difference between the jejunum and the ileum was noted in that neurotensin-induced stimulation of peristaltic activity was observed in a smaller number of the segments in the jejunum than in the ileum. A nonpeptide neurotensin receptor antagonist, SR 48692, 2-[(1-(7-chloro-4-quinolinyl)-5-(2,6-dimethoxyphenyl) pyrazol-3-yl)carbonylamino]tricyclo(3.3.1.1.(3.7))decan++ +-2-carboxylic acid (90 nM), abolished both the inhibitory and excitatory effects. Apamin (10 nM) abolished the inhibitory effect. From these results, neurotensin appears to exert both excitatory and inhibitory actions, via its receptors sensitive to SR 48692, on peristaltic activity in guinea-pig small intestine. The excitatory action varies with an increasing gradient toward the terminal end of the small intestine, and the inhibitory action involves apamin-sensitive mechanism.

Carbachol-induced [Ca2+]i oscillations in single smooth muscle cells of guinea-pig ileum

1. Changes in cytosolic Ca2+ concentration ([Ca2+]i) produced by carbachol (CCh) were measured in single smooth muscle cells of guinea-pig ileum using a Ca(2+)-sensitive fluorescent dye, fura-2, to clarify the underlying mechanisms of muscarinic [Ca2+]i oscillations. 2. Half of the cells, when exposed to 0.2 microM CCh, exhibited repeated changes in [Ca2+]i giving a serrated appearance. The oscillatory changes in [Ca2+]i were very similar to those evoked by increasing extracellular K(+) concentration ([K+]o) to 30 mM, which were abolished by removal of extracellular Ca2+, nifedipine and La3+, but remained unchanged after depletion of internal Ca2+ stores with cyclopiazonic acid, thapsigargin and ryanodine. 3. Every individual [Ca2+]i oscillation was just like a [Ca2+]i increase generated spontaneously in about 8% of cells or triggered by an action potential evoked by a current pulse in current-clamped cells. 4. In the remaining half of the cells exposed to 0.2 microM CCh, slower [Ca2+]i oscillations were elicited and every individual [Ca2+]i oscillation was always preceded by the fast brief increase in [Ca2+]i. 5. [Ca2+]i oscillations elicited by 2 microM CCh were temporally and functionally distinct from those induced by high [K+]o. They were more or less regular in the periodicity and pattern, comprised pacemaker potential-like [Ca2+]i increases or sinusoidal types of [Ca2+]i increases, and could be elicited even in 100 mM K+(o). 6. Removal of extracellular Ca2+ or application of nifedipine, methoxyverapamil (D600), diltiazem or La3+ during CCh (2 micro M)-induced [Ca2+]i oscillations caused them to disappear. In cells i which internal Ca2+ stores were depleted, 2 microM CCh did not evoke [Ca2+]i oscillations but occasionally induced single or repeated generation of the increase in [Ca2+]i with a serrated appearance. 7. The results indicate that CCh can induce two types of [Ca2+]i oscillation in guinea-pig ileal smooth muscle cells; one arises from Ca2+ influx associated with action potential discharges and the other from periodic release of Ca2+ from internal stores. The latter [Ca2+]i oscillation requires extracellular Ca2+ to sustain it.

Pharmacological characterization of adrenoceptors mediating contractile and relaxant responses to noradrenaline in the longitudinal muscle of guinea-pig ileum

Mechanical responses to noradrenaline (NA) were recorded in longitudinal muscle strips from the terminal and intermediate regions (3-10 cm and 30-40 cm from the ileo-caecal junction, respectively) of the guinea-pig ileum. NA(0.16-1,600 microM) produced a concentration-dependent contraction in the terminal ileum with the EC50 value of 11.9 +/- 4.3 microM (n = 5). In the intermediate ileum, NA produced relaxation at concentrations ranging from 0.016 microM to 1.6 microM. Responses to NA at 16 microM varied among preparations: no noticeable change in tension, a moderate relaxation and a small contraction. At higher concentrations, NA produced contractile responses and their peak tension increased in a concentration-dependent manner. The contractile effect of NA in the terminal ileum remained unaltered after treatment with propranolol (1.4 microM) or yohimbine (1.1 microM), or a combination of these drugs. In the intermediate ileum, the relaxant effect of NA was markedly reduced or abolished by propranolol (1.4 microM). Yohimbine (1.1 microM) had little effect on NA-induced relaxation. The contractile effect of NA in both the terminal ileum and intermediate ileum was inhibited by prazosin (1.1 microM), so that the contractions were converted to relaxation or markedly reduced. Propranolol abolished the relaxant response induced by NA at 0.16 microM, but did not inhibit those induced by NA at 1.6 microM. Methoxamine (0.16-1,600 microM) produced a concentration-dependent contraction in both the terminal ileum and the intermediate ileum. The EC50 was 93.5 +/- 28.5 microM (n = 8) in the terminal ileum and 83.3 +/- 27.7 microM (n = 10) in the intermediate ileum. There was no significant difference between the values. The results showed that NA is capable of producing contraction or relaxation in the longitudinal muscle layer of the terminal and intermediate regions of the guinea-pig ileum. The contraction, which is mediated by alpha 1-adrenoceptors, predominates in the terminal ileum, but relaxation, which is mediated by beta-adrenoceptors and uncharacterized adrenoceptors, predominates in the intermediate ileum.

[Surgical results of total replacement of aortic root]

Total aortic root replacement was performed on 19 cases since December 1979 to May 1995. They were devided in two groups. First 7 cases were operated by original Bentall procedure with inclusion technique (group A). Succeeding 12 cases were operated by Carrel patch method or Cabrol procedure without inclusion maneuver. There were 2 operative deaths in group A (28.6%) and was one death in group B (8.3%) respectively. The operation time and the extracorporeal circulation time were significantly shorter in group A than that in group B. Anastomotic leakage was noted in 2 cases of group A. One of them required reoperation and another one with coronary ostial leakage died of congestive heart failure. We concluded that non-inclusion method for aortic root replacement was superior to conventional inclusion technique and reimplantation of both coronary ostia with Carrel patch method was the best tactics especially for Marfan syndrome in terms of long term results.

[A family of hereditary motor and sensory neuropathy type I with a mutation (Arg98-->His) in myelin Po--report on a second Japanese family]

A 46-year-old housewife had complaints of insidiously progressive muscle weakness and paresthesia in the distal lower limbs. On neurological examination, a slight to moderate degree of muscle weakness with slight atrophy was observed in the bilateral intrinsic hand muscles. A severe degree of muscle weakness with moderate atrophy was observed in tibialis anterior, gastrocnemius and soleus muscles. Muscle stretch reflexes were decreased in the upper limbs and absent in the lower limbs, without pathologic reflexes. She had a steppage gait. Vibratory sensation was slightly decreased in the hands and moderately decreased in the feet. Touch, pain and temperature sensations were also moderately decreased only in the feet. On laboratory examination, glycosuria (5.6g/dl) was noted. Fasting blood sugar was 226mg/dl with an elevated hemoglobin A1C level (12.7%). The right median motor and sensory nerve conduction velocities were 14.8 and 20.3 m/sec, respectively, with a markedly prolonged distal latency. No muscle action potential was obtained from stimulation of the right tibial nerve. Also, no nerve action potential was elicited from stimulation of the right sural nerve. A fascicular biopsy of the right sural nerve revealed the presence of both demyelinated and remyelinated axons, and an onion-bulb formation with a marked decrease in the density of the myelinated fibers. Based on the neurological examination and nerve conduction studies of the family members, a younger sister, younger brother and an elder daughter of the proband were found to be affected by demyelinating polyneuropathy. Diabetes mellitus was not found among the family members with laboratory evidences of demyelinating polyneuropathy. Based on the family history, an uncle on the mother's side of the proband, the proband's grandmother and a younger daughter of a proband's brother were considered to be affected. The uncle and grandmother had diabetes mellitus. Therefore, we concluded that this family had HMSN type I with autosomal dominant inheritance. In the studies on fluorescence in situ hybridization, and restriction fragment length polymorphism of the genomic DNA of the proband, a DNA duplication in the 17p11.2-12 region was not observed. However, the direct sequencing analysis of DNA fragments from genomic DNA encoding the Po gene of the proband revealed a substitution of histidine for arginine at the codon 98 in the extramembranous domain of Po. She was heterozygous for the mutant allele and normal allele. Alterations in the tertiary structure of the extramembranous domain of Po may result in an impairment of the peripheral myelin compaction. This is the second Japanese family with the same mutation (Arg98-->His) of myelin Po as reported previously by us, and this type of case is rare in the literature. Therefore, the mutation at the codon 98 may play a critical role in the development of the myelin abnormality in HMSN type IB.

Thrombopoietin induces tyrosine phosphorylation of Stat3 and Stat5 in human blood platelets

Thrombopoietin is known to be essential for megakaryocytopoiesis and thrombopoiesis. Recently, we and others have shown that thrombopoietin induces rapid tyrosine phosphorylation of Jak2 and other proteins in human platelets and BaF3 cells, genetically engineered to express c-Mpl, a receptor for thrombopoietin. The Jak family of tyrosine kinases are known to mediate some of the effects of cytokines or hematopoietic growth factors by recruitment and tyrosine phosphorylation of a variety of Stat (signal transducers and activators of transcription) proteins. Hence, we have investigated whether Stat proteins are present in platelets and, if so, whether they become tyrosine phosphorylated in response to thrombopoietin. We immunologically identified Stat1, Stat2, Stat3, and Stat5 in human platelet lysates. Thrombopoietin induced tyrosine phosphorylation of Stat3 and Stat5 in these cells. Thrombopoietin also induced tyrosine phosphorylation of Stat3 and Stat5 in FDCP-2 cells genetically engineered to constitutively express human c-Mpl. Thus, our data indicate that Stat3 and Stat5 may be involved in signal transduction after ligand binding to c-Mpl and that this event may have a role in megakaryopoiesis/thrombopoiesis or possibly a mature platelet function such as aggregation.