Influence of concomitant percutaneous transluminal angioplasty with percutaneous coronary intervention on outcomes in patients with stable lower extremity artery disease

Background

Patients with stable lower extremity artery diseases (LEAD) frequently present with coronary artery diseases; thus, concomitant percutaneous transluminal angioplasty (PTA) at the time of percutaneous coronary intervention (PCI) is often performed. We investigated the influence of concomitant PTA on both cardiovascular (CV) and limb outcomes in the Korean National Health Insurance Service registry.

Methods

Among 78,185 patients undergoing PCI between 2012 and 2015, 6,563 patients (279 for the PTA+PCI group vs. 6,284 for the PCI group) suffering from stable LEAD without limb ischemia were included. Major adverse CV events (MACEs) were defined as a composite of CV death, myocardial infarction (MI) and coronary revascularization. Patients were followed for at least 3 years.

Results

After 1:5 propensity score matching was conducted, 279 patients in the PTA+PCI group and 1,385 patients in the PCI group were compared. The risk of all-cause death was higher in the PTA+PCI group than in the PCI group, whereas the risks of MACE, MI, revascularization, stroke, CV death and bleeding event were not different between the 2 groups in the matched cohort. In contrast, the risks of end-stage renal diseases and unfavorable limb outcomes were higher in the PTA+PCI group than in the PCI group (Figure 1). Mediation analyses revealed that amputation and repeat Percutaneous transluminal angioplasty after discharge significantly mediated the association between the concomitant PTA and all-cause death (Figure 2).

Conclusions

CPTA at the time of PCI is not associated with an increased risk of CV events but may increase the risk of all-cause death by increasing unfavorable renal and limb outcomes in patients with stable LEAD.

Funding Acknowledgement

Type of funding sources: None.

Efficacy and safety of micafungin for the prophylaxis of invasive fungal infection during neutropenia in children and adolescents undergoing allogeneic hematopoietic SCT

The objective of this study was to evaluate the efficacy and safety of micafungin for the prevention of invasive fungal infection (IFI) during the neutropenic phase of allogeneic hematopoietic SCT (allo-HSCT) in children and adolescents. This was a prospective, multicenter, open-label, single-arm study. Micafungin was administered i.v. at a dose of 1 mg/kg/day (max 50 mg) from the beginning of conditioning until neutrophil engraftment. Treatment success was defined as the absence of proven, probable, possible or suspected IFI through to 4 weeks after therapy. From April 2010 to December 2011, 155 patients were enrolled from 11 institutions in Korea, and 147 patients were analyzed. Of the 147 patients, 121 (82.3%) completed the protocol without premature interruption. Of the 132 patients in whom micafungin efficacy could be evaluated, treatment success was achieved in 119 patients (90.2%). There was no proven fungal infection in any patient. The number of patients with probable, possible and suspected IFI was two, two and nine, respectively. Thirty-five patients (23.8%) experienced 109 adverse events (AEs) possibly related to micafungin. No patients experienced grade IV AEs. Two patients (1.4%) discontinued micafungin administration due to adverse effects. None of the deaths were related to the study drug.

Ret finger protein inhibits muscle differentiation by modulating serum response factor and enhancer of polycomb1

Skeletal myogenesis is precisely regulated by multiple transcription factors. Previously, we demonstrated that enhancer of polycomb 1 (Epc1) induces skeletal muscle differentiation by potentiating serum response factor (SRF)-dependent muscle gene activation. Here, we report that an interacting partner of Epc1, ret finger protein (RFP), blocks skeletal muscle differentiation. Our findings show that RFP was highly expressed in skeletal muscles and was downregulated during myoblast differentiation. Forced expression of RFP delayed myoblast differentiation, whereas knockdown enhanced it. Epc1-induced enhancements of SRF-dependent multinucleation, transactivation of the skeletal α-actin promoter, binding of SRF to the serum response element, and muscle-specific gene induction were blocked by RFP. RFP interfered with the physical interaction between Epc1 and SRF. Muscles from rfp knockout mice (Rfp(-/-)) mice were bigger than those from wild-type mice, and the expression of SRF-dependent muscle-specific genes was upregulated. Myotube formation and myoblast differentiation were enhanced in Rfp(-/-) mice. Taken together, our findings highlight RFP as a novel regulator of muscle differentiation that acts by modulating the expression of SRF-dependent skeletal muscle-specific genes.

Constitution and telomere dynamics of bone marrow stromal cells in patients undergoing allogeneic bone marrow transplantation

We evaluated the genotypic origin of mesenchymal stem cells (MSC) following sex-mismatched allogeneic bone marrow transplantation (BMT), and investigated the telomere dynamics in MSC in normal individuals and patients after BMT. The study population consisted of 11 patients with hematologic disorders who showed complete chimerism after BMT. Telomere length was measured in MSC using Southern blotting analysis in eight patients and 18 healthy subjects as a control group. Following culture, MSC were identified by the expression of SH2 and SH4, and lack of CD14, CD34, and CD45. All MSC showed the recipient genotype, based on the results of fluorescent in situ hybridization analysis using X-chromosome satellite probes or microsatellite DNA polymorphism analysis. The mean telomere length in MSC from normal controls was 7.2+/-0.53 kb (range, 6.12-7.78), and progressive telomere shortening was seen with age. There was no significant difference in MSC telomere length between the BMT group and age-matched controls. This study confirmed that the MSC isolated from the recipients of allogeneic BMT did not have the donor genotype, despite complete chimerism. Moreover, MSC were demonstrated to show progressive loss of telomere length with age, but the telomeres in MSC were not affected by BMT.

Accelerated reendothelialization with suppressed thrombogenic property and neointimal hyperplasia of rabbit jugular vein grafts by adenovirus-mediated gene transfer of C-type natriuretic peptide

BACKGROUND

Vein graft disease limits the late results of coronary revascularization. C-type natriuretic peptide (CNP) inhibits the growth of vascular smooth muscle cells. Given the effects of CNP on cGMP cascade, we hypothesized that transfected CNP genes modulate endothelial repair and thrombogenicity in the vein graft.

METHODS AND RESULTS

Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of adenovirus vectors containing CNP gene (Ad.CNP) or Escherichia coli lac Z gene (Ad.LacZ) and then interposed in the carotid artery. Reendothelialization, mural thrombi formation, and intima/media ratio were evaluated on the 14th and 28th postoperative days. More reendothelialization was seen in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts both at 14 days (0.81+/-0.05 versus 0.30+/-0.14, P<0.01) and at 28 days (0.96+/-0.01 versus 0.45+/-0.08, P<0.001). The mural thrombus area was smaller in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts. Neointimal thickening was significantly suppressed in the Ad.CNP group. The in vitro wound assay with human coronary artery endothelial cells revealed significant potentiation of the wound repair process by CNP and atrial natriuretic peptide administration.

CONCLUSIONS

Infected Ad.CNP accelerated reendothelialization and suppressed thrombosis and neointimal hyperplasia. The method may potentially prevent vein graft disease in patients undergoing coronary artery revascularization.

Relationship between bone marrow failure syndromes and the presence of glycophosphatidyl inositol-anchored protein-deficient clones

Because of the insensitivity of the Ham test, paroxysmal nocturnal haemoglobinuria (PNH) has been inaccurately viewed as a late clonal complication of aplastic anaemia (AA). To clarify the relationship between PNH and marrow failure, we tested for the presence of glycosylphosphatidyl-anchored protein-deficient (GPI-AP) granulocytes in large cohorts of patients with AA, myelodysplasia (MDS), and pure haemolytic PNH. A PNH clone was detected in 32% of new AA patients and 18% of MDS patients. In serial studies, this proportion did not change up to 15 years after diagnosis, suggesting that expansion of aberrant cells is an early event (i.e. prior to initial presentation). For all patients with a PNH clone, on average 14% of PNH granulocytes were found on presentation and 37% at 10 years. Patients with PNH but without cytopenia showed higher percentages of GPI-AP-deficient cells than did those with the AA/PNH syndrome. After immunosuppression, there was no change in the contribution of PNH clone to blood production, arguing against the "immune-escape" theory in PNH. Clinically, a high proportion of GPI-AP-deficient cells correlated with marrow hypercellularity. GPI-AP-deficient cells were similarly present in patients with and without karyotypic abnormalities. Our results indicate that the GPI-AP-deficient clones show quantitative and kinetic differences between classic haemolytic PNH and PNH with marrow failure, in which the evolution rate is low later in the course of the disease.

Increased cytotoxic T cells with effector phenotype in aplastic anemia and myelodysplasia

OBJECTIVE

We hypothesized that an active autoimmune process in aplastic anemia (AA) corresponds to the expansion of cytotoxic lymphocytes (CTLs) displaying mature effector phenotype. We determined whether the numbers of effector CTLs in blood of patients with bone marrow failure syndromes are elevated and correlate with the disease activity and responsiveness to immunosuppression.

PATIENTS AND METHODS

We analyzed samples from patients with AA, myelodysplastic syndrome (MDS), polytransfused patients with nonimmune-mediated hematologic disease, and normal controls for the presence of effector T lymphocytes using four-color flow cytometry. Expression of CD57 and loss of CD28 on CD8+CD3+ CTL were used as markers for the terminal effector phenotype. In addition, intracellular staining for perforin and granzyme B was preformed. The numbers of effector CTL did not differ between healthy individuals and hematologic controls and the two groups were pooled.

RESULTS

The percentages of CD8+CD28- and CD8+CD28-CD57+ cells were significantly higher in AA and MDS patients than in controls. There was a trend toward a gradual decrease in the effector CTLs from the high values observed in untreated new patients and patients who did not respond to immunosuppression, intermediate levels for partial responders and complete responders, to the lowest levels seen in controls. However, severity of pancytopenia did not correlate with the size of the effector cell population. In contrast to CD57+ CTLs, expression of perforin or granzyme B in the cytotoxic effector cells did not differ in AA patients from those of controls.

CONCLUSIONS

Our results indicate that phenotypically defined effector CTLs are increased in AA and MDS and the effector phenotype may be useful to isolate and characterize antigen-specific T cells in AA in order to delineate the possible inciting or driving agents in AA.

Thiazolidinediones, peroxisome proliferator-activated receptor gamma agonists, regulate endothelial cell growth and secretion of vasoactive peptides

Insulin resistance has been highlighted as a common causal factor for glucose intolerance, hypertension and dyslipidemia, all of which are cardiovascular risk factors. A new class of antidiabetic agents, thiazolidinediones (TZDs), has been developed and demonstrated to improve insulin sensitivity. TZDs are high affinity ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), the crucial transcription factor for adipocytes. Recent studies showed that PPARgamma is also expressed in monocytes/macrophages and is suggested to be involved in atherosclerosis. We could detect PPARgamma gene transcript in several cultured endothelial cells (human aortic endothelial cells (HAoECs), human coronary artery endothelial cells (HCAECs), human umbilical vein endothelial cells (HUVECs) and bovine carotid artery endothelial cells (BAECs)) as well as human coronary arteries we examined. Since endothelial dysfunction is critical for atherosclerosis, we investigated the effects of TZDs, troglitazone (TRO) and pioglitazone (PIO), on endothelial cell growth and secretion of C-type natriuretic peptide (CNP), which we demonstrated as a novel endothelium-derived relaxing peptide, and endothelin (ET), a potent vasoconstrictor, using HAoECs, HCAECs, HUVECs and BAECs. When all these cultured endothelial cells were daily treated with TRO and PIO for 5 days, both TRO and PIO (10(-8)M) significantly stimulated (3)H-thymidine incorporation of all these endothelial cells. In contrast, higher dose of TRO and PIO (10(-5)M) significantly suppressed DNA synthesis. TRO and PIO also exerted the compatible effect on the increase of cell numbers. TRO and PIO significantly enhanced CNP secretion from BAECs. In contrast, ET secretion from BAECs was suppressed by both TRO and PIO in a dose-dependent manner. The results of the present study suggest that TZDs modulate endothelial functions, including regulation of endothelial cell growth and secretion of endothelium-derived vasoactive substances, which affect vascular tone and remodeling in the process of atherosclerosis.

C-type natriuretic peptide induces redifferentiation of vascular smooth muscle cells with accelerated reendothelialization

We recently reported that C-type natriuretic peptide (CNP) occurs in vascular endothelial cells and acts as a vascular-type natriuretic peptide. In the present study, we stimulated the cGMP cascade in proliferating smooth muscle cells (SMCs), in which particulate guanylate cyclase-B, the specific receptor for CNP, is predominantly expressed, by use of an adenovirus encoding rat CNP cDNA (Ad.CNP). In the Ad.CNP-treated cultured SMCs, CNP caused the growth inhibition of SMCs at G(1) phase with an early increase of p21(CIP1/WAF1) expression and subsequent upregulation of p16(INK4a). The expression of smooth muscle myosin heavy chain-2, which is the molecular marker of highly differentiated SMCs, was reinduced in the Ad.CNP-treated SMCs. The Ad.CNP-treated SMCs also reexpressed particulate guanylate cyclase-A, which shows high affinity to atrial and brain natriuretic peptide and is exclusively expressed in well-differentiated SMCs. CNP, which was overexpressed in rabbit femoral arteries in vivo at the time of balloon injury, significantly suppressed neointimal formation. Furthermore, an enhancement of the expression of smooth muscle myosin heavy chain-2 occurred in the residual neointima. In addition, early regeneration of endothelial cells was observed in the Ad.CNP-infected group. Thus, stimulation of cGMP cascade in proliferating dedifferentiated SMCs can induce growth inhibition and redifferentiation of SMCs with accelerated reendothelialization.

Overexpressed human RAD50 exhibits cell death in a p21(WAF1/CIP1)-dependent manner: its potential utility in local gene therapy of tumor

Previously, mouse RAD50, one of the mammalian DNA recombination repair genes, was reported to have limited epitopic homology to p53. Here we report the functional characteristics of overexpressed human RAD50 (hRAD50). Transient transfection of hRAD50 in several cultured cells caused cytotoxicity. We established tetracycline-regulated, stable hRAD50 expression systems in SaOS-2 cells, which retain mutated p53, and in HeLa cells. After tetracycline withdrawal, cell death and multinucleated giant cells were observed with increased hRAD50 expression, and p21(WAF1/CIP1) but not p53 was increased. Transient transfection of hRAD50 in HCT116 p21(-/-) cells caused no cytotoxicity, but there was a significantly decreased survival rate in p21(+/+) cells. These cytotoxic effects of overexpressed hRAD50 in HeLa, SaOS-2, and HCT116 p21(+/+) cells were partially blocked by pretreatment of cells with N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, a pan-caspase inhibitor. When the hRAD50 expression cDNA was injected intratumorally with liposomes, it regressed or delayed tumor development in the animal model and nitric oxide synthase expression was induced in the tumor tissues that had regressed. Our results indicate that overexpressed hRAD50 has an antiproliferation activity in vitro and in vivo in a p21-dependent manner.

Increased expression of atrial natriuretic peptide in the kidney of rats with bilateral ureteral obstruction

BACKGROUND

Whether the postobstructive diuresis can be related to an altered regulation of local atrial natriuretic peptide (ANP) in the kidney was investigated.

METHODS

Three groups of rats had both of their ureters obstructed for 48 hours. The kidneys were taken without releasing the obstruction in one group [bilateral ureteral obstruction (BUO)]. The obstruction was released in the other two groups and the animals were kept for 4 and 24 hours thereafter to collect urinary data (BUR-4 and BUR-24, respectively). Plasma and urine ANP levels were measured by radioimmunoassay. The mRNA expression of ANP, natriuretic peptide receptor-A (NPR-A), and NPR-C was determined by reverse transcription-polymerase chain reaction. ANP receptors were also quantitated by in vitro autoradiography. The activity of guanylyl cyclase was determined by the amount of cGMP generated in response to ANP.

RESULTS

Urinary volume and sodium excretion increased in BUR-4, along with the ANP mRNA expression in the kidney and the urinary ANP excretion. The ANP excretion positively correlated with the urinary volume and sodium excretion. The mRNA expression of both NPR-A and NPR-C was decreased by BUO, the latter being far more prominently affected. The maximal binding capacity of radiolabeled ANP was decreased in the glomerulus and papilla in BUO. Not only the urinary parameters but also the mRNA expression of ANP, NPR-A, and NPR-C were comparable between BUR-24 and control rats. ANP-stimulated cGMP generation was reduced in the glomerulus and papilla in BUO animals, which was rapidly resumed following the release of the obstruction.

CONCLUSIONS

Postobstructive diuresis may be due partially to an increased ANP activity in the kidney.

Telomere length changes in patients with aplastic anaemia

To investigate telomere changes in patients with aplastic anaemia (AA) and clinical factors influencing the telomere dynamics, telomere length (TL) was measured in peripheral blood mononuclear cells using Southern blot analysis of 42 patients with AA and 39 healthy normal controls. Nineteen patients received supportive treatment only, while the remaining 23 patients received immunosuppressive therapy with anti-thymocyte globulin or anti-lymphocyte globulin +/- cyclosporin A. In AA patients, TL was on average 1.41 kb shorter than that of age-matched normal controls (P < 0.001). In patients treated with immunosuppression, the mean TL of non-responders was significantly shorter than that of age-matched normal controls (P < 0.001), while no difference in TL was detected in responders compared with controls. Positive correlation was observed between the extent of telomere shortening, the severity of neutropenia (P = 0.05) and the degree of mean corpuscular volume elevation (P = 0.005) at the time of the study. However, there was no correlation with time elapsed since diagnosis (P = 0.214). These findings suggest that haematopoietic stem cells in patients with AA rapidly lose TL at the onset of the disease. The TL shortening may reflect the severity of impairment of haematopoiesis.

Clinical efficacy of granulocyte transfusion therapy in patients with neutropenia-related infections

Granulocyte transfusions have been advocated by some for the treatment of severe, progressive infections in neutropenic patients who fail to respond to antimicrobial agents and recombinant hematopoietic growth factors. We conducted the current study to determine an appropriate method of granulocyte mobilization in healthy donors, and to evaluate the safety and efficacy of granulocyte transfusion therapy in patients with neutropenia-related infections. To mobilize granulocytes (n=55), healthy normal donors were stimulated in one of the following ways: (1) dexamethasone, 3 mg/m2 intravenously 15 min prior to leukapheresis (n = 5); (2) granulocyte colony-stimulating factor (G-CSF), 5 microg/kg subcutaneously 12 to 14 h prior to collection (n=37); or (3) G-CSF and dexamethasone (n= 13). The mean granulocyte yield from stimulation with G-CSF plus dexamethasone was significantly higher than from stimulation with dexamethasone or G-CSF alone. Twenty-five patients with severe neutropenia-related infections unresponsive to appropriate antimicrobial agents received a total of 55 granulocyte transfusions. The patients from whom fungi or Gram-negative organisms were isolated showed a more favorable response than those infected with Gram-positive organisms. However, the responses to the granulocyte transfusion therapy could not be correlated with the transfused dose, mobilization agents, or the 1 h or 24 h post-transfusion absolute neutrophil counts. We conclude that granulocyte transfusion therapy may be clinically useful for neutropenia-related infections by fungi or Gram-negative organisms.

Cyclosporine impairs the guanylyl cyclase activity of the natriuretic peptide receptor in the glomerulus

In order to elucidate the involvement of the atrial natriuretic peptide (ANP) and its receptor (natriuretic peptide receptor; NPR) system in cyclosporine-induced nephrotoxicity, we investigated the cyclosporine A (CsA)-induced changes in characteristics of the NPR/guanylyl cyclase system in the glomerulus and inner medulla of the rat kidney. CsA was administered intramuscularly to rats for 2 weeks (CsA group). Particulate guanylyl cyclase activity was measured in glomerular and inner medullary membranes. For receptor characteristics, quantitative in vitro receptor autoradiography was performed. The guanylyl cyclase activity in the glomerulus from the CsA group was attenuated compared with that from the control. However, the activity in the inner medulla was not affected by CsA treatment. Direct application of CsA to normal glomerular membrane completely abolished the ANP-induced guanylyl cyclase activation. Binding studies, using(125)I-ANP, revealed that B(max)was decreased in the CsA group, while K(d)was not affected in the glomerulus. However, in the inner medulla, neither B(max)nor K(d)was affected by CsA treatment. CsA did not displace the(125)I-ANP bindings to NPRs in the normal rat kidney. Local tissue ANP as well as plasma ANP concentration in both groups was not significantly different. These results indicate that CsA impairs the guanylyl cyclase activity mainly in the glomerulus by the decrease in NPR population and/or by direct inhibition, suggesting that the ANP/NPR system might be involved in CsA-induced nephrotoxicity.

Rubella-associated aplastic anemia treated by syngeneic stem cell transplantations

A 14-year-old boy presented with aplastic anemia 3 months after contracting rubella. Stem cell transplantations from his identical twin were carried out. Successful engraftment occurred only when conditioning therapy was given prior to the infusion of the syngeneic stem cells, supporting an immune mechanism to explain the pathogenesis of virus-associated aplastic anemia.

Ruptured Klebsiella pneumoniae liver abscess after high-dose cyclophosphamide for severe aplastic anemia

A 19-year-old woman with severe aplastic anemia who had previously failed antithymocyte globulin/cyclosporine A received high-dose cyclophosphamide without bone marrow rescue. On day +14, she complained of right upper quadrant abdominal pain and fever. A CT scan of the abdomen showed multiple liver abscesses with rupture and Klebsiella pneumoniae was isolated from blood. In spite of aggressive antibiotic therapy, she rapidly deteriorated and died of overwhelming sepsis. To our knowledge, our patient is the first case of fatal ruptured liver abscess after high-dose cyclophosphamide in a patient with severe aplastic anemia.

Nosocomial cluster of Candida lipolytica fungemia in pediatric patients

Candida lipolytica has rarely been reported as a human pathogen. An apparent outbreak of Candida lipolytica fungemia (n = 5 cases) occurred in a pediatric ward over a 9-week period. The five patients infected were hospitalized in three adjacent rooms and cared for by the same healthcare workers. The index patient had central venous catheter-related fungemia, whereas the second patient, who was in the adjacent single room, had transient fungemia. Three additional cases of fungemia occurred in patients with hematological disorders who shared the same room; all three patients had central venous catheters and had been receiving oral fluconazole prophylaxis (50 mg/day for more than 3 weeks) at the time of infection. In vitro susceptibility testing of the strains showed that the MIC of fluconazole for all the isolates was 32 microg/ml. Random amplified polymorphic DNA analysis provided evidence of the clonal origin of the isolates, but the source of the outbreak was not identified. All four patients with persistent fungemia were successfully treated via catheter removal or empiric amphotericin B treatment. This outbreak shows the potential for the nosocomial epidemic transmission of Candida lipolytica.

Diminished adenylate cyclase activity and aquaporin 2 expression in acute renal failure rats

BACKGROUND

The present study was aimed at investigating the changes of aquaporin 2 (AQP2) expression and its underlying mechanisms in ischemic acute renal failure (ARF).

METHODS

ARF was induced by clamping the both renal arteries for 60 minutes in rats. Two or seven days later, AQP2 expression and trafficking were determined in the kidney by Western blot analysis and immunohistochemistry. The activity of adenylate cyclase was also measured.

RESULTS

The urinary flow rates in ARF-2 and ARF-7 day were significantly increased in association with decreases of urine osmolality. While there was decreased expression of AQP2 in the cortex, outer medulla, and inner medulla in ARF, it was most pronounced in the outer medulla. The AQP2 expression was reduced in the apical membrane-enriched fraction as well the subapical vesicle-enriched fraction in ARF; however, the degree was greater in the former than in the latter. Immunohistochemical study also showed a markedly decreased expression of AQP2 in the collecting duct in ARF. cAMP generation in response to arginine vasopressin (AVP) in the kidney was attenuated in ARF, most prominently in the outer medulla. cAMP generation in the outer medulla in response to forskolin was not affected, but sodium fluoride was significantly blunted in ARF.

CONCLUSIONS

The AVP-stimulated adenylate cyclase activity is impaired in ARF, secondary to a defect at the level of the G protein. The expression of AQP2 was reduced as a consequence, which may in part account for urinary concentration defect in ARF.

Successful allogeneic bone marrow transplantation for childhood-onset refractory anemia with ringed sideroblasts

Refractory anemia with ringed sideroblasts (RARS) is an extremely rare type of myelodysplastic syndrome in children. We describe a 10-year-old boy with RARS presented with pancytopenia. He remained relatively stable with only a few transfusions until age of 20 years, when he underwent an allogeneic bone marrow transplantation (BMT) because of increased transfusion requirements. He remains in complete chimeric state at 20 months posttransplant with normal hematologic parameters. To our knowledge, this is the first description of successful BMT in a patient with childhood-onset RARS. The indication of BMT for this rare disorder in children is discussed.

Effects of L-arginine on cyclosporin-induced alterations of vascular NO/cGMP generation

BACKGROUND

Cyclosporin (CsA)-induced vascular dysfunction has been attributed to a diminished role of the nitric oxide (NO)/cGMP-mediated vasodilator mechanism. The present study was aimed at investigating whether L-arginine, the substrate of NO synthesis, ameliorates CsA-induced vascular dysfunction.

METHODS

Male Sprague-Dawley rats were used throughout the study. The thoracic aorta was isolated from normal rats and acutely treated with CsA (10(-4) mol/l, 60 min) in vitro, or the aorta was taken from rats treated with CsA (25 mg/kg/day, i.m., 1 week). The vascular relaxation response to acetylcholine, and tissue levels of NO metabolites and cGMP were determined. The vascular expression of NO synthase (NOS) isoforms was also determined by western blot analysis.

RESULTS

Acute treatment with CsA in vitro markedly attenuated the vasorelaxation response to acetylcholine, which was completely restored by L-arginine. The vascular accumulation of NO metabolites in response to acetylcholine was decreased significantly by CsA, which was prevented by cotreatment with L-arginine. CsA decreased the cGMP accumulation in response to both acetylcholine and sodium nitroprusside. L-Arginine restored, although not completely, acetylcholine-stimulated cGMP generation, whereas it did not affect sodium nitroprusside-stimulated cGMP generation. Following chronic CsA treatment in the whole animal, the vasorelaxation response to acetylcholine was decreased significantly along with tissue levels of NO metabolites; this was preserved by L-arginine-supplementation. Vascular expression of iNOS protein was decreased by CsA treatment along with decreased tissue accumulation of NO metabolites. L-Arginine supplementation did not modify the altered expression of NOS proteins.

CONCLUSION

These results suggest that CsA causes an L-arginine-sensitive vascular dysfunction which is associated with impaired generation of NO and cGMP.

Synchronization of diffusively coupled oscillators near the homoclinic bifurcation

It has been known that a diffusive coupling between two limit cycle oscillations typically leads to the in-phase synchronization and also that it is the only stable state in the weak-coupling limit. Recently, however, it has been shown that the coupling of the same nature can result in the distinctive dephased synchronization when the limit cycles are close to the homoclinic bifurcation, which often occurs especially for the neuronal oscillators. In this paper we propose a simple physical model using the modified van der Pol equation, which unfolds the generic synchronization behaviors of the latter kind and in which one may readily observe changes in the sychronization behaviors between the distinctive regimes as well. The dephasing mechanism is analyzed both qualitatively and quantitatively in the weak-coupling limit. A general form of coupling is introduced and the synchronization behaviors over a wide range of the coupling parameters are explored to construct the phase diagram using the bifurcation analysis.

Telomere length changes in patients undergoing hematopoietic stem cell transplantation

Telomere length indicates the replicative history of cells, serving as a molecular measure of the replicative potential remaining in cells. To investigate telomere length changes in hematopoietic stem cells, patients undergoing hematopoietic stem cell transplantation (HSCT) were evaluated. Fifteen patients after allogeneic bone marrow transplantation (allo-BMT group), seven patients after autologous peripheral blood stem cell transplantation (auto-PBSCT group), and 39 healthy controls were studied. Telomere length was measured in peripheral mononuclear cells by Southern blot hybridization. There was no significant difference between the allo-BMT and the auto-PBSCT groups. In the allo-BMT group, the mean telomere length of recipients was 2.01 kb shorter than that of their donors (P = 0. 008), and was 1.59 kb shorter than that of age-matched putative normal controls (P = 0.002). Telomere shortening in the allo-BMT group was equivalent to 41.4 years of aging in the donors, and to 52. 4 years of aging in the normal controls. The mean telomere length in the auto-PBSCT group was 2.36 kb shorter than that of the age-matched putative controls (P = 0.043), which was equivalent to 61.5 years of aging in normal controls. The extent of telomere shortening in the allo-BMT group showed a trend to negative correlation with the number of mononuclear cells infused. These findings suggest that hematopoietic stem cells after HSCT lose telomere length and these shortened telomeres may result in a higher incidence of clonal disorders later in life.

Differentially-altered vascular guanylate cyclase isoforms in experimental hypertensive rats

Pathophysiological implications of the vascular nitric oxide (NO)/cGMP pathway were investigated in various rat models of hypertension. The expression of brain and endothelial constitutive NO synthases (bNOS, ecNOS) was determined by Western blot analysis, and the biochemical activity of soluble and particulate guanylate cyclases (GC) was assessed by the amount of cGMP generated in the thoracic aortae of rats with deoxycorticosterone acetate (DOCA)-salt, two-kidney, one dip (2K1C), and spontaneous hypertension (SHR). Plasma nitrite/ nitrate levels were decreased in DOCA-salt and 2K1C hypertension, and increased in SHR. The vascular expression of bNOS as well as that of ecNOS was decreased along with tissue nitrite/nitrate contents in DOCA-salt and 2K1C hypertension. The expression of both bNOS and ecNOS was increased in SHR with concomitant changes of tissue nitrite/nitrate contents. The activity of soluble GC was decreased, and that of particulate GC was increased in DOCA-salt hypertension. The soluble GC activity was increased, while the particulate GC activity was not affected in 2K1C hypertension. The soluble GC activity was not significantly changed, but the particulate GC activity was decreased in SHR. These results indicate that the high blood pressure is associated with differentially-altered vascular NO/cGMP pathway in different models of hypertension.

Activation of particulate guanylyl cyclase by Vibrio vulnificus hemolysin

Recently we reported that Vibrio vulnificus hemolysin, an exotoxin produced by V. vulnificus, dilates rat thoracic aorta via elevated cGMP levels without affecting nitric oxide synthase. We investigated the mechanism further by observing the guanylyl cyclase activities in cytosolic, membrane, unfractionated, or reconstituted preparations. Hemolysin did not activate guanylyl cyclase in the membrane or cytosolic fraction, while it activated guanylyl cyclase in unfractionated or reconstituted preparation. The increased activity was not inhibited by the HS-142-1, a microbial polysaccharide which antagonizes atrial natriuretic peptide receptor, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a soluble guanylyl cyclase inhibitor. However, it was attenuated by 6-(phenylamino)-5,8-quinolinedione (LY 83.583), which inhibits the catalytic domain of both guanylyl cyclases, and by cholesterol, which blocks hemolysin-incorporation into the membrane. Removing ATP, a cofactor of particulate guanylyl cyclase, attenuated the activation and ATPgammaS, a non-phosphorylating analog, restored it. These results suggest that V. vulnificus hemolysin activates particulate guanylyl cyclase via hemolysin incorporation into the vascular smooth muscle cell membrane in cooperation with certain unidentified cytosolic component(s).

Fanconi anemia screening by diepoxybutane and mitomicin C tests in Korean children with bone marrow failure syndromes

Fanconi anemia (FA) is an autosomal recessive disorder of progressive bone marrow failure in patients with congenital malformations. FA is different from acquired aplastic anemia (AA) in terms of the natural course and treatment options. As the frequency of FA is unknown in Korea, we conducted screening tests using DNA clastogenic agents, diepoxybutane (DEB) and mitomicin C (MMC) in southwestern Korea. Forty-three children with AA or other bone marrow failure syndromes and siblings of known FA were evaluated. Six patients with AA (6/24=25.0%) and a 2-month-old patient with myelodysplastic syndrome were found to have increased chromosomal breakage to both DEB and MMC, confirming the diagnosis of FA. No overlap in chromosomal breakage to both agents was found between the FA group and non-FA group. The frequency of FA in this study, much higher than those of previous studies in Korea which did not incorporate the above tests, was similar to that of other countries. DEB and MMC tests were readily feasible and useful in screening FA in patients with AA as well as other bone marrow failure syndromes. A nation-wide screening and registry for FA should be initiated since FA requires different therapeutic and management options from idiopathic AA.

Acute hemolytic crisis with fulminant hepatic failure as the first manifestation of Wilson's disease: a case report

We report a 27-year-old woman who developed Coombs' negative hemolytic anemia and fulminant hepatic failure as the initial manifestation of Wilson's disease. Unmeasurably low level of serum alkaline phosphatase provided a clue to the diagnosis of Wilson's disease. The diagnosis was established with the presence of Kayser-Fleischer ring, decreased serum ceruloplasmin level, and elevated urine and serum copper levels. In spite of repeated plasmapheresis, she died of multiorgan failure on the fifth hospital day.

Granulocytic sarcoma as isolated extramedullary relapse after donor lymphocyte infusion in a patient with CML who relapsed after allogeneic bone marrow transplantation: a case report

Isolated granulocytic sarcoma (GS) has rarely been reported in a patient who underwent allogeneic bone marrow transplantation (BMT) for chronic myelogenous leukemia (CML). We report here a patient who developed an isolated GS after achieving hematologic and cytogenetic remission by donor lymphocyte infusion for the relapse of CML following BMT. The size of GS was slightly decreased after local irradiation of 1,500 cGy without further systemic chemotherapy or immunotherapy. He remained in hematologic and cytogenetic remission without systemic relapse of CML for 8 months. Thereafter, he died of sepsis. The appropriate treatment of GS and impact of its occurrence on prognosis following allogeneic BMT has yet to be determined.

A case of Marfan syndrome with acute monoblastic leukemia

We report on an 18-year-old man who had both acute monoblastic leukemia and Marfan syndrome. A diagnosis of Marfan syndrome was established by those characteristics of arachnodactyly, ectopia lentis, mitral valve prolapse, and mitral regurgitation. Findings on bone marrow examination of the patient showed that most of nucleated cells were monoblasts and immunophenotype of those cells showed CD13+, CD33+, CD56+, and HLA-DR+. To our knowledge, this is the second report of leukemia in Marfan syndrome in the world.

Life-threatening carboplatin hypersensitivity during conditioning for autologous PBSC transplantation: successful rechallenge after desensitization

Carboplatin hypersensitivity has rarely been reported in patients receiving repeated cycles of therapy, but has not been reported in transplant settings. We report a case of carboplatin hypersensitivity during conditioning for autologous PBSC transplantation. The patient suddenly developed chest tightness, hemoptysis, hypoxia and hypotension, resulting in a transient myocardial ischemia. The pathophysiologic mechanism for the event seemed to be non-immune-mediated direct histamine release given the lack of prior exposure to platinum. Contrary to advice not to continue further treatment with carboplatin by some authors, we successfully desensitized the patient and subsequently gave more carboplatin as a part of conditioning. Awareness of carboplatin as one of the causes of hypersensitivity may help avoid further problems either by substitution or desensitization, along with premedications.

A case of chronic graft-versus-host-disease following allogeneic peripheral blood stem cell rescue for poor graft function after bone marrow transplantation

To overcome poor graft function after allogeneic bone marrow transplantation (BMT), the use of peripheral blood stem cells (PBSC) instead of bone marrow is gaining more popularity because of its advantages. There may, however, be an increased risk of graft-versus-host-disease (GVHD) because of the large number of lymphocytes present in a leukapheresis product. An 18-year-old man with severe aplastic anemia underwent an allogeneic BMT using his HLA-identical sister. After initial excellent graft take for 8 months, his blood counts gradually decreased to 2.8 x 10(9)/L of white cells and 28 x 10(9)/L of platelets with marrow cellularity of < 10%. After allogeneic granulocyte-colony stimulating factor mobilized PBSC rescue, the patient's blood counts recovered satisfactorily. Around 1 year after the boost, he developed chronic GVHD that responded to prednisolone and cyclosporin A. He is now well on low-dose steroids at day +1055 after PBSC rescue. The present case is the first experience of a long-term follow-up who underwent allogeneic PBSC rescue in Korea.

Aspergillus nidulans infection in a patient with chronic granulomatous disease

Aspergillus nidulans is one of the several species of Aspergillus with low pathogenicity. The significant infections of A. nidulans in human have rarely been reported, almost exclusively in patients with chronic granulomatous disease (CGD). CGD is a primary immunodeficiency disease which results from the absence of the NADPH oxidase in the phagocytic cells, leading to recurrent pyogenic infection and granuloma and abscess formation. Here we report a fatal case A. nidulans infection in a six-year-old boy with chronic granulomatous disease. A. nidulans was isolated from the culture of a paraspinal abscess and Aspergillus was detected in the surgical tissue by in situ hybridization. The patient succumbed despite prolonged treatment with high-dose amphotericin B, itraconazole and interferon-alpha. To our knowledge, this is the first report of A. nidulans infection in Korea.

Reconstruction of the immune system after unrelated or partially matched T-cell-depleted bone marrow transplantation in children: functional analyses of lymphocytes and correlation with immunophenotypic recovery following transplantation

Reconstitution of the immune system following T-cell-depleted bone marrow transplantation (BMT) in children has yet to be fully elucidated. Thus, we prospectively studied the recovery of immune function in 64 children who underwent T-lymphocyte-depleted marrow transplants using either matched family member donors or matched unrelated donors. We measured in vitro posttransplantation proliferative responses to phytohemagglutinin (PHA), concanavalin A, pokeweed mitogen, and Candida albicans antigen and assessed unidirectional allogeneic mixed-lymphocyte culture (MLC) responses at various times. A total of 129 healthy individuals served as normal controls for these assays. Responses to T-cell mitogens normalized within 12 months posttransplantation, while MLC responses normalized by 9 months. The presence of graft-versus-host disease (grade II or greater) and cytomegalovirus infection was associated with delays in immune function recovery. Importantly, immune function recovery correlated temporally with a rise in peripheral lymphocyte count. In contrast, the CD4/CD8 ratio was not predictive of immune recovery. Knowledge of immune function recovery may guide clinicians in devising strategies to minimize the risk of infection post-BMT.

Successful program to prevent aspergillus infections in children undergoing marrow transplantation: use of nasal amphotericin

Aspergillus infections in the pediatric bone marrow transplant (BMT) patients are usually fatal. We began the use of a prophylactic nasal spray of amphotericin in 1990. This nasal spray was provided in addition to low-dose intravenous amphotericin. During the time of this study, the number of fatal cases of aspergillus in the pediatric BMT population was reduced significantly from 13.8% to 1.8% (P < 0.0025) thereby suggesting that the use of nasal amphotericin in this population helps to prevent fatal aspergillus infections. The lack of significant side-effects and the ease of administration make this a very helpful preventive measure in the supportive care of pediatric bone marrow transplant patients.

Reconstruction of the immune system after unrelated or partially matched T-cell-depleted bone marrow transplantation in children: immunophenotypic analysis and factors affecting the speed of recovery

We prospectively studied immune reconstitution in 102 children who underwent T-lymphocyte depleted bone marrow transplants using either closely matched unrelated donors or partially matched familial donors by assaying total lymphocyte counts (TLC), T-cell subsets, B cells, and natural killer cells. TLC, CD3+, and CD4+ T-cell counts remained depressed until 2 to 3 years posttransplant, whereas CD8+ T-cell counts normalized by 18 months, resulting in an inverted CD4:CD8 ratio until 12 months posttransplant. Although the percentage of NK cells was elevated early posttransplant, their absolute numbers remained normal. CD20+ B cells were depressed until 12 to 18 months posttransplant. Factors affecting immunophenotypic recovery were analyzed by nonparametric statistics. Younger patients tended to have higher TLC posttransplant. Higher marrow cell doses were not associated with hastened immunophenotypic recovery. Graft-versus-host disease (GVHD) and/or its treatment significantly delayed the immune reconstitution of CD3+, CD4+, and CD20+ cells. The presence of cytomegalovirus was associated with increased CD8+ counts and a decrease in the percentages of CD4+ and CD20+ cells.

Vibrio vulnificus hemolysin dilates rat thoracic aorta by activating guanylate cyclase

Hemolysin produced by Vibrio vulnificus caused hypotension and tachycardia in rats and dilated rat thoracic aorta. Hemolysin-induced vasodilatation of the aorta was not affected by N omega-nitro-L-arginine methyl ester and aminoguanidine, NO synthase inhibitors, whereas the vasodilatation was inhibited by LY 83,583, a guanylate cyclase inhibitor. Hemolysin elevated cGMP levels, and the elevation was abolished by LY 83,583. These results suggest that V. vulnificus hemolysin activates guanylate cyclase independently of NO synthase, and the subsequent increase in cGMP levels results in vasodilatation.

Effects of calcium antagonists on contractions of chorionic arteries in normal and preeclampsia placenta

This study was undertaken to observe the effects of organic or inorganic calcium antagonists and to investigate the involvement of cyclic nucleotides in regulating the vascular tone in the chorionic artery from normal or preeclamptic placenta. KCI and prostaglandin (PG) F2 alpha produced marked and constant contractions in chorionic arterial preparations of both normal and preeclamptic placentas. Nifedipine (NIF), verapamil (VER) and diltiazem (DIL) reduced the tension that had been produced by KCI and PGF2 alpha in a concentration-dependent fashion in both preparations, and the potency order of the three agents was NIF > VER > DIL. In preeclamptic arteries, however, the magnitudes of vasodilatation induced by NIF and DIL were much smaller than those in normal chorionic arteries. Mg2+ and Cd2+ also relaxed the tension induced by KCI and PGF2 alpha. In preeclamptic chorionic artery, the vasodilatation induced by Mg2+ was significantly potentiated, while that by Cd2+ was not. Removing endothelium did not alter cyclic GMP content in both preparations. In both preparations contracted by PGF2 alpha, nitroprusside markedly increased cyclic GMP content, but neither cyclic GMP nor cyclic AMP content was affected by acetylcholine, NIF, isopro-terenol, or Mg2+. The above results suggest that neither cyclic AMP nor cyclic GMP is involved in regulating the vascular tone of chorionic artery and that sensitivity of the artery in preeclampsia to the inhibitory action of calcium antagonist might be different from that in normal placenta.