[Surgical correction of an incomplete endocardial cushion defect in a 66-year-old male with the remarkable pulmonary hypertension]

A surgical case of a 66-year-old male with an endocardial cushion defect (ECD) is reported. He had preoperative pulmonary hypertension (80/25 mmHg, Pp/Ps 0.61), hypoxia (63.7 mmHg) and decreased creatinin clearance (45.7 ml/min). Respiratory condition was New York Heart Association's (NYHA's) grade III. Angiocardiography showed a typical gooseneck deformity associated with mitral and tricuspid valve regurgitations with the cleft (Seller's grade II and III). As surgical correction, direct suture of the cleft in an anterior leaflet with mitral annuloplasty, patch closure of the ostium primum defect with Xenomedical patch and tricuspid annuloplasty were performed. Postoperative data were restored to NYHA grade I. decreased pulmonary artery pressure (43/21 mmHg) and resistances (Pp/Ps 0.36). The only three surgical treatments of an incomplete ECD were reviewed in over 65-year-old patients in Japan included one perioperative death. Although we suggest it should be actively taken surgical repair even in elderly patients with pulmonary hypertension.

Pharmacological properties of non-adrenergic, non-cholinergic inhibitory transmission in chicken gizzard

1. Non-adrenergic, non-cholinergic (NANC) inhibitory transmission in chicken gizzard was studied by use of intracellular microelectrode techniques. Changes in membrane potential in response to NANC nerve stimulation were recorded in the gizzard smooth muscle pretreated with atropine (1 microM) and guanethidine (1 microM). 2. Field stimulation of the intramural nerves (FS) evoked inhibitory junction potentials (i.j.ps) which were abolished by tetrodotoxin (1 microM), but not inhibited at all by K+ channel blockers including apamin (0.5 microM), tetraethylammonium (TEA, 10 mM), charybdotoxin (0.2 microM) and glibenclamide (10 microM). 3. NG-nitro-L-arginine (3 mM), an inhibitor of nitric oxide (NO) synthase, inhibited i.j.ps. The effect was reversed by L-arginine (3 mM), but not by D-arginine (3 mM). 4. 8-Bromo cyclic GMP (100 microM), a membrane permeable analogue of cyclic GMP, produced a membrane hyperpolarization which was blocked by TEA (10 mM) or glibenclamide (10 microM). 5. NO at concentrations of up to 400 microM affected neither i.j.ps nor resting membrane potential. On the other hand, NO (80 microM) caused the membrane to hyperpolarize in the smooth muscle of guinea-pig ileum. 6. These results suggest that in the chicken gizzard, NANC i.j.ps may not arise from opening of conventional types of K+ channel and that NO seems unlikely to be involved in the generation of i.j.ps. A possible mechanism by which the inhibitory effect of NG-nitro-L-arginine on i.j.ps was brought about will be discussed.

Thrombin cleaves recombinant human thrombopoietin: one of the proteolytic events that generates truncated forms of thrombopoietin

A heterogeneity in the molecular weight (Mr) of thrombopoietin (TPO) has been reported. We found several thrombin cleavage sites in human, rat, murine, and canine TPOs, and also found that human TPO undergoes selective proteolysis by thrombin. Recombinant human TPO (rhTPO) was incubated with human platelets in the presence of calcium ions to allow the generation of thrombin, and was cleaved into low Mr peptide fragments. The cleavage was completely inhibited by hirudin, indicating that the proteolysis was mediated by thrombin. In a platelet-free system, analyses of thrombin cleavage by immunoblotting using anti-human TPO peptide antibodies revealed that the four major thrombin-cleaved peptide fragments were selectively generated depending on the digestion time. The amino acid sequences of the thrombin-polypeptides were further analyzed, and two major thrombin cleavage sites were determined. One of them was at AR191-T192 in the C-terminal domain of TPO, and thrombin cleaved first at this site. The other site at GR117-T118 in the N-terminal domain was subsequently cleaved by prolonged thrombin digestion. As a result, the biological activity of TPO was modulated. The generation of truncated forms of TPO by thrombin may be a notable event in view of the platelet-related metabolism of TPO.

Thrombopoietin and thrombin induce tyrosine phosphorylation of Vav in human blood platelets

Thrombopoietin has an essential role in megakaryopoiesis and thrombopoiesis. To investigate the signaling processes induced by thrombopoietin, we have employed human platelets and recently demonstrated that thrombopoietin induces rapid tyrosine phosphorylation of Jak-2, Tyk2, Shc, Stat3, Stat5, p120(c-cbl) and other proteins in human platelets. Because the apparent molecular weight of a major tyrosine phosphorylated protein in platelets stimulated by thrombopoietin is approximately 85 to 95 kD, we examined the possibility that this could be Vav, a 95-kD proto-oncogene product. Specific antisera against Vav recognized the same 95 kD protein in lysates of Jurkat cells, which are known to express Vav, and platelets, indicating that platelets have Vav. Thrombopoietin induced rapid tyrosine phosphorylation of Vav in platelets without an elevation in cytosolic free calcium concentration or activation of protein kinase C. Vav was also tyrosine phosphorylated upon treatment of platelets with thrombin, collagen, or U46619, which activate phospholipase C, leading to an increased ionized calcium concentration and activation of protein kinase C. Ionomycin or phorbol 12-myristate 13-acetate (PMA) also induces tyrosine phosphorylation of Vav, suggesting that an increase in ionized calcium concentration or activation of protein kinase C may lead to phosphorylation of Vav. Thrombopoietin also induced tyrosine phosphorylation of Vav in FDCP-2 cells, genetically engineered to express human c-Mpl (FDCP-hMpl5). However, neither ionomycin nor PMA induced an increase in tyrosine phosphorylation of Vav in FDCP-hMpl5 cells, suggesting that the calcium and protein kinase C pathways of Vav phosphorylation may be unique to platelets. Further, Vav became incorporated into the Triton X-100 insoluble 10,000 g sedimentable residue in an aggregation-dependent manner, suggesting that it may have a regulatory role in platelet cytoskeletal processes. Vav was constitutively associated with a 28-kD adapter protein, Grb2, which is also incorporated into the cytoskeleton in an aggregation-dependent fashion. Lastly, we found that Vav is cleaved when there is activation of calpain, a protease that may have a role in postaggregation signaling processes. Our data suggest that thrombopoietin and other agonists may induce tyrosine phosphorylation of Vav by different mechanisms and Vav may also be involved in signaling during platelet aggregation by its redistribution to the cytoskeleton.

Cladistic analysis of phylogenetic relationships among tribes Cicereae, Trifolieae, and Vicieae (Leguminosae)

A cladistic analysis of tribes Cicereae, Trifolieae, and Vicieae was carried out using 33 morphological, anatomical, karyological, and chemotaxonomical characteristics. Transformation polarities of the character states were developed by comparison with the character states of the genus Galega, the sister group of the tribes. Cicereae and Vicieae were found to be a monophyletic group, and Trifolieae was its sister group. The seven synapomorphic characters of Cicereae and Vicieae were presumed to be: germination hypogeal vs. epigeal; first leaf in seedlings scarious vs. laminous; leaves paripinnately and tendrilous vs. imparipinnately and etendrilous; postchalazal vascular bundle present in seed coats vs. absent; a cotyledon flap present at antihilar side vs. absent; radicles short in seeds vs. long; and plumules long in seeds vs. short.

[Combined surgery for coronary artery disease and thoracic aortic disease]

Combined surgery in 6 cases who had coronary artery disease and thoracic aortic disease simultaneously was analyzed. Case # 1 had ascending aortic replacement under deep hypothermic circulatory arrest because of iatrogenic aortic dissection caused by aortic clamp during the routine coronary artery bypass grafting (CABG). Case # 2 had DeBakey type II chronic dissection. Case # 3 had type I aortic dissection 4 years after the initial CABG. Both case # 2 and # 3 had ascending aortic replacement under retrograde cerebral perfusion along with CABG. Transverse aortic replacement was performed in case # 4, # 5 and # 6 under selective cerebral perfusion along with CABG. Case # 4 was associated with ascending-transverse aortic aneurysm. Case # 5 had aortitis syndrome complicated with severe coronary ostial stenosis and cervical branch stenosis. Case # 6 also had aortitis syndrome, severe coronary ostial stenosis, heavily calcified ascending-transverse aorta, and mitral and aortic regurgitation. This case had mitral and aortic valve replacement additionally. Case # 2 died of low cardiac output syndrome and multi-organ failure postoperatively. Case # 4 did not recover from profound shock that followed the preoperative acute myocardial infarction. The problems of low cardiac output syndrome caused by long interval of ischemic cardiac arrest, and also the problems of proximal anastomotic site of saphenous vein grafts were discussed.

In vitro long-term culture of human primitive hematopoietic cells supported by murine stromal cell line MS-5

When Lin-CD34+CD38- cells from normal human cord blood were cocultured with MS-5, colony forming cells were maintained for over 8 weeks. Prevention of contact between MS-5 and Lin-CD34+CD38- cells by using a membrane filter was negligible for this activity, indicating that the activity of MS-5 on human primitive hematopoietic cells may be due to soluble factor(s) secreted from MS-5. We tried to purify this activity by a [3H]TdR incorporation assay. The activity was found in 150 kD fraction and was neutralized with anti-mSCF (stem cell factor) antibody. Another 20-30 kD fraction synergized with mSCF to stimulate the growth of Lin-CD34+CD38- cells but failed alone. This fraction supported the growth of the G-CSF (granulocyte-colony stimulating factor)-dependent cell line FD/GR3, FDC-P2 transfected with mG-CSF receptor cDNA. This synergy was canceled in the presence of soluble mG-CSF receptor. Addition of anti-mSCF antibody and soluble mG-CSF receptor to the culture completely abrogated the activity of MS-5-culture supernatant. These results indicate the activity of MS-5 on Lin-CD34+CD38- cells is due to synergistic effect of mSCF and mG-CSF.

Possible narrowed assignment of the loci of monosomy 21-associated microcephaly and intrauterine growth retardation to a 1.2-Mb segment at 21q22.2

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Molecular mapping of a translocation breakpoint at 14q13 in a patient with mirror-image polydactyly of hands and feet

Mirror hands and feet (MIM, 135750) is a rare congenital anomaly, and mirror-image polydactyly is considered to be a variant of mirror hands and feet. To our knowledge, seven patients with the disorder have been reported in the literature. Parent-to-child transmission was reported in two families, which may indicate a single-gene defect inherited in an autosomal dominant fashion. We had previously encountered a boy with mirror-image polydactyly whose karyotype showed 46,XY,t(2;14) (p23.3;q13) de novo. We hypothesized that at least one of the putative genes responsible for the determination of an anterior-posterior limb pattern is disrupted by a translocation breakpoint. In this study, we identified a yeast artificial chromosome clone spanning a translocation breakpoint at 14q13, and the breakpoint was confirmed to be located between two loci, AFM200ZH4 and D14S306, within a genetic distance of 0.6 cM.

A phylogeny of the chloroplast gene rbcL in the Leguminosae: taxonomic correlations and insights into the evolution of nodulation

Phylogenetic analysis of the chloroplast-encoded rbcL gene in Leguminosae are consistent with previous hypotheses in suggesting that the family as a whole is monophyletic, but that only two of its three subfamilies are natural. The earliest dichotomies in the family appear to have involved tribes Cercideae or Cassieae (subtribe Dialiinae), followed by Detarieae/ Macrolobieae, all of which are members of subfamily Caesalpinioideae. The remainder of the family is divided into two clades: (1) Mimosoideae and the caesalpinioid tribes Caeasalpinieae and Cassieae (subtribes Ceratoniinae and Cassiinae); (2) Papilionoideae. Basal groups within Papilionoideae are, as expected, elements of the grade tribes Sophoreae and Swartzieae. Major clades within Papilionoideae include: (1) a Genistoid Alliance comprising Genisteae, Crotalarieae, Podalyrieae, Thermopsideae, Euchresteae, and also some Sophoreae; (2) a clade marked by the absence of one copy of the chloroplast inverted repeat, with which are associated Robinieae. Loteae, and some Sophoreae; (3) Phaseoleae, Desmodieae. Psoraleeae, and most Millettieae, a group also marked by presence of pseudoracemose inflorescences; and (4) a well-supported clade comprising Aeschynomeneae, Adesmieae, and some Dalbergieae. Nodulation is most parsimoniously optimized on the rbcL strict consensus tree as three parallel gains, occurring in Papilionoideae, the caesalpioioid ancestors of Mimosoideae, and in the genus Chamaecrista (Caesalpinieae: Cassieae).

[A case of ventricular septal perforation treated surgically with an infarction exclusion technique]

We report an 85-year-old woman with postinfarction interventricular septal perforation. She underwent successful emergent surgical treatment by a slightly modified method based on David-Komeda's procedure. Perforation in this case occurred four days after acute myocardial infarction. Preoperative Qp/Qs was 2.58, and pulmonary artery pressure was 34/25 mmHg. The area of infarction was large, and the perforation was the linear type 2.5 cm long near the apex. A probe was not able to pass through the perforation due to its complicated configuration. A double Xenomedica patch was sutured on the left side of the interventricular septum without excising the infarcted area. The suture line was placed on healthy myocardium apart from the infarcted area. The Xenomedica patch was sandwiched between the closure line of the ventriculotomy. Four days after surgery, residual shunt was observed by echocardiogram, but this subsequently disappeared on the 17th postoperative day. The patient was discharged from our hospital on the 57th postoperative day, and is now doing quite well.

[A case of bladder calculus due to a ruptured balloon fragment of a Foley catheter]

I report a case of bladder calculus developing on a ruptured balloon fragment of the Foley catheter as the nidus. A 65-year-old man suffering from cerebral infarction had been managed with an indwelling urethral Foley catheter for one month. Since the balloon could no longer be deflated, the Foley catheter was removed after rupturing the balloon by overinflation. Four months later, a 3-cm bladder calculus was detected on the plain abdominal roentgenogram. Transurethral cystolitholapaxy revealed a ruptured balloon fragment buried in the core of the calculus. Urine culture was positive for Proteus mirabilis and the stone composition was struvite.

[Clinicopathological features of interstitial pneumonia associated with amyopathic dermatomyositis]

We studied clinicopathological characteristics of interstitial pneumonia associated with amyopathic dermatomyositis. The subjects comprised two men and three women, and their mean age was 58.2 years. All subjects had cruptions specific for dermatomyositis, but had no signs of myositis. They all presented with acutely or subacutely developed coughing and dyspnea. Results of tests for anti-Jo-1 antibody were negative in all cases. Chest X-ray films showed infiltrations or streaky shadows, or both in the middle and lower lung fields. Analysis of bronchoalveolar lavage fluid revealed abnormally high percentages of lymphocytes and neutrophils. In one patients a specimen obtained by open lung biopsy showed homogeneous cell infiltrations in alveolar septa and regional alveolar damage. That patient was successfully treated with cyclosporin and corticosteroids in early phase of the disease. The other four patients received immunosuppressive agents after respiratory failure developed. All four died despite having received high-dose corticosteroid and immunosuppressive therapy. Examination of autopsy specimens showed diffuse alveolar damage.

Locations of crossover breakpoints within the CMT1A-REP repeat in Japanese patients with CMT1A and HNPP

The crossover breakpoints for Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are located in the CMT1A-REP repeat flanking a 1.5-Mb region of chromosome 17p11.2-12. The precise locations of the breakpoints are heterogeneous, and we analyzed the relative frequency distribution of breakpoints in 33 unrelated Japanese CMT1A and 3 unrelated HNPP families. The CMT1A-REP repeat region was divided into five regions, A, B, C, D and E, based on restriction site differences between the proximal and distal CMT1A-REP repeats. The frequency distribution of breakpoints within the CMT1A-REP repeat in the Japanese patients was 3% in region A, .78% in B/C and 19% in D, which is similar to that in Caucasian patients. This result also indicates that an 8-kb region defined by region B/C is a recombinational hotspot within the CMT1A-REP repeat in Japanese patients.

Tetramelic mirror-image polydactyly and a de novo balanced translocation between 2p23.3 and 14q13

We report on a male infant with tetramelic mirror-image polydactyly and a de novo, balanced reciprocal translocation between 2p23.3 and 14q13. This patient suggests that a novel gene, which functions in the morphogenesis of the hands and feet along the anterior-posterior axis, may be located at 2p23.3 or 14q13.

Crkl is constitutively tyrosine phosphorylated in platelets from chronic myelogenous leukemia patients and inducibly phosphorylated in normal platelets stimulated by thrombopoietin

Platelet functions such as aggregation and clot retraction are often abnormal in chronic mylogenous leukemia (CML) patients. However, the molecular mechanisms of these altered functions are unknown. As expression of the p210bcr-abl oncogene product, a constitutively active tyrosine kinase, is known to have an essential role in the pathogenesis of CML and tyrosine phosphorylation is intimately involved in various aspects of platelet activation, we examined the pattern of protein tyrosine phosphorylation in platelets from 15 CML patients by immunoblotting with a monoclonal antiphosphotyrosine antibody (4G10). Before and after stimulation with thrombin, the only consistent difference between normal and CML platelets was the presence of a tyrosine phosphorylated protein with a relative molecular weight of 39 kD. This tyrosine phosphorylated protein was identified as crid, an SH2, SH3 containing adapter protein. Thus, as previously demonstrated for neutrophils from CML patients, tyrosine phosphorylation of p39crkl persists in mature platelets. No tyrosine phosphorylation of crid was detected following stimulation with thrombin in normal platelets. However, crkl became incorporated into the Triton X-100 insoluble residue following thrombin stimulation in a manner dependent on platelet aggregation. Further, we found that crkl is an endogenous substrate for calpain, a protease that may be involved in postaggregation signaling processes. This suggests that crkl may be involved in the reorganization of the cytoskeleton during normal platelet aggregation and its tyrosine phosphorylation in CML platelets may contribute to the abnormal platelet function in CML patients. Finally, we found that thrombopoietin induces tyrosine phosphorylation of crk1 in normal platelets and FDCP cells genetically engineered to express human c-Mpl. This suggests that crk1 can be phosphorylated by a kinase other than p210bcr-abl and that crk1 may have a role in signaling by thrombopoietin.

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.