Adipocyte-derived plasma protein adiponectin acts as a platelet-derived growth factor-BB-binding protein and regulates growth factor-induced common postreceptor signal in vascular smooth muscle cell

BACKGROUND: Vascular smooth muscle cell proliferation plays an important role in the development of atherosclerosis. We previously reported that adiponectin, an adipocyte-specific plasma protein, accumulated in the human injured artery and suppressed endothelial inflammatory response as well as macrophage-to-foam cell transformation. The present study investigated the effects of adiponectin on proliferation and migration of human aortic smooth muscle cells (HASMCs). Methods and Results- HASMC proliferation was estimated by [(3)H] thymidine uptake and cell number. Cell migration assay was performed using a Boyden chamber. Physiological concentrations of adiponectin significantly suppressed both proliferation and migration of HASMCs stimulated with platelet-derived growth factor (PDGF)-BB. Adiponectin specifically bound to (125)I-PDGF-BB and significantly inhibited the association of (125)I-PDGF-BB with HASMCs, but no effects were observed on the binding of (125)I-PDGF-AA or (125)I-heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) to HASMCs. Adiponectin strongly and dose-dependently suppressed PDGF-BB-induced p42/44 extracellular signal-related kinase (ERK) phosphorylation and PDGF beta-receptor autophosphorylation analyzed by immunoblot. Adiponectin also reduced PDGF-AA-stimulated or HB-EGF-stimulated ERK phosphorylation in a dose-dependent manner without affecting autophosphorylation of PDGF alpha-receptor or EGF receptor. CONCLUSIONS: The adipocyte-derived plasma protein adiponectin strongly suppressed HASMC proliferation and migration through direct binding with PDGF-BB and generally inhibited growth factor-stimulated ERK signal in HASMCs, suggesting that adiponectin acts as a modulator for vascular remodeling.     

Acute myeloid leukemia with t(8;21)(q22;q22) manifesting as granulocytic sarcomas in the rhinopharynx and external acoustic meatus at relapse after high-dose cytarabine: case report and review of the literature

We report a 31-year-old female with t(8;21)(q22;q22) acute myeloid leukemia (AML), M2 in the FAB classification. Complete remission was achieved with daunorubicin and cytarabine induction therapy followed by three courses of high-dose cytarabine consolidation. Only 3 months later, the patient relapsed with granulocytic sarcomas (GSs) in her rhinopharynx, external acoustic meatus, and bone marrow. She received focal radiation for the GSs and successfully underwent reinduction chemotherapy. Subsequently, she received a matched related donor peripheral blood stem cell transplantation followed by high-dose chemotherapy and is now in a second remission. We summarized 79 reported cases of t(8;21) AML with GS and reviewed the literature to identify differences in the characteristics of t(8;21) AML with GS between adults and children. To our knowledge, this is the first report of pharyngeal GS in t(8;21) AML, and focal irradiation plus more intensive postinduction therapy during first remission, such as allogeneic-SCT, may be effective in adult t(8;21) AML patients with GS.     

Effect of post-transplant double filtration plasmapheresis on recurrent focal and segmental glomerulosclerosis in renal transplant recipients

In the present study, we reviewed the effect of post-transplant double filtration plasmapheresis (DFPP) on recurrent focal segmental glomerulosclerosis (FSGS) in the transplanted kidney allograft. Sixteen patients with post-transplant recurrent FSGS were enrolled in this study. Out of 16 patients with recurrent FSGS after transplantation, five did not receive DFPP and lost their grafts, while 11 did receive DFPP and four of these patients lost their grafts. Seven patients were able to maintain normal renal function for an average observation period of 57.1 +/- 40.7 months (range 7-125 months). In five patients who had a significant reduction in urinary protein after DFPP, the urinary protein level decreased from 26.60 +/- 23.05 g/day (range 3.34-62.6 g/day) to 2.95 +/- 3.42 g/day (range 0.02-8.64 g/day) and renal function was maintained. The beneficial effects of DFPP on graft outcome were more likely to occur if the patients experienced a marked drop in urinary excretion. Thus, post-transplant DFPP appears to be effective for reducing urinary protein levels and improving long-term graft survival. With the small numbers in this trial, however, none of the findings were statistically significant. We recommend the use of post-transplant DFPP to prevent the progression of recurrent FSGS.     

Megakaryoblastic transformation of polycythemia vera with hypercalcemia

Polycythemia vera (PV) is known to occasionally transform into acute leukemia. Administration of alkylating agents seems to be associated with an increased risk of leukemic transformation of PV. Hypercalcemia is a serious complication of malignancies, but it is uncommon in acute leukemia. In the majority of malignancies with hypercalcemia, elevated parathyroid hormone-related protein (PTHrP) is thought to be the main cause of hypercalcemia. We report a rare case of megakaryoblastic transformation of PV with hypercalcemia. A 62-year-old man was diagnosed as having PV in 1983, and he had received ranimustine and busulfan. He developed acute megakaryoblastic leukemia 17 years after the initial diagnosis of PV. Serum calcium was elevated, the serum level of intact parathyroid hormone (PTH) was suppressed, and the level of intact PTHrP was slightly elevated. He had no lytic bone lesions; however, uncoupling of bone turnover due to an increase in bone resorption and a decrease in bone formation was detected by using biochemical markers. Since the level of PTHrP was slightly elevated from the normal value, we speculated that PTHrP produced in the local field by leukemic cells might have been more abundant than circulating PTHrP. Pamidronate and adrenocortical hormone were effective in reducing the serum calcium level. However, the patient died shortly after the start of induction chemotherapy. The prognosis of cases of PV that has transformed into acute leukemia is generally poor because the majority of such cases are refractory to chemotherapy.     

A glutamate residue at the C terminus regulates activity of inward rectifier K+ channels: implication for Andersen's syndrome

G protein-coupled inward rectifiers (GIRKs) are activated directly by G protein betagamma subunits, whereas classical inward rectifiers (IRKs) are constitutively active. We found that a glutamate residue of GIRK2 (E315), located on a hydrophobic domain of the C terminus, is crucial for the channel activation. This glutamate (or aspartate) residue is conserved in all members of the Kir family. Substitution of alanine for the glutamate on GIRK1, GIRK2, and IRK2, expressed in HEK293 cells, greatly reduced the whole-cell currents. The whole-cell current of GIRK channels with a constitutively active gate, GIRK2(V188A), [Yi, B. A., Lin, Y. F., Jan, Y. N. & Jan, L. Y. (2001) Neuron 29, 657-667] was also reduced by the same glutamate mutation. Mean open time and conductance of single channels in GIRK2 and IRK2 were not affected by the mutation, indicating that the reduced whole-cell current resulted from a lowered probability of channel activation. The mutated GIRK and IRK showed normal trafficking to the cell membrane. The mutated GIRK2 retained the ability to interact with G protein betagamma subunits, and it showed almost the same inwardly rectifying property as the wild type. The mutated GIRK1 and GIRK2 retained ion selectivity to K(+) ions. This glutamate residue corresponds to one of the residues causing Andersen's syndrome [Plaster, N. M., Tawil, R., Tristani-Firouzi, M., Canun, S., Bendahhou, S., Tsunoda, A., Donaldson, M. R., Iannaccone, S. T., Brunt, E., Barohn, R., et al. (2001) Cell 105, 511-519]. Our interpretation is that this region of the glutamate residue is crucial in relaying the activating message from the ligand sensor region to the gate.     

Variants of calpain-10 gene and its association with type 2 diabetes mellitus in a Chinese population

Variants of calpain-10 gene (CAPN 10) have recently been reported to be associated with type 2 diabetes (T2DM). Haplotype combination 112/121 defined by three single nucleotide polymorphisms (SNPs) (UCSNP-43, -19 and -63) of CAPN 10 conferred the highest risk for T2DM in Mexican-Americans. In this study, we aim to examine whether these genetic variants contribute to the susceptibility for T2DM in a Chinese population. The frequencies of these three SNPs were determined in 168 patients with T2DM and 104 controls. Distribution of alleles, genotypes and haplotypes at three loci were not significantly different between the two groups. No difference was observed in the 112/121 haplotype combination distribution. However, haplotype combination 112/221 was more prevalent in the control group than in T2DM group (16.35% versus 7.14%, p = 0.025). Control subjects with haplotype combination 112/121 had higher serum cholesterol level than others without haplotype combination 112/121 (5.7 +/- 1.4 versus 5.2 +/- 0.7, p = 0.011). Our results suggest that haplotype combination 112/221 associated with reduced risk for T2DM and haplotype combination 112/121 might be a risk factor for increased serum cholesterol in Chinese population.     

Case of chronic-phase chronic myelogenous leukemia with an abdominal hematopoietic tumor of leukemic clone origin

We report a 59-year-old man with chronic myelogenous leukemia (CML) in chronic phase who presented with a large abdominal tumor. Biopsy revealed proliferation of granulocytic-, erythroid-, and megakaryocytic-lineage cells in a retroperitoneal lymph node. The BCR/ABL fusion gene was detected on a paraffin-embedded tissue section of the lymph node by double-color fluorescence in situ hybridization, indicating an extramedullary hematopoietic tumor of CML origin. This patient has achieved a complete cytogenetic response for 19 months with imatinib mesylate (STI571; Gleevec), in association with the regression of the tumor. However, the development of an extramedullary tumor in chronic-phase CML generally indicates a poor prognosis, because it commonly consists of blast proliferation and is followed by blast crisis in the marrow within a few months. This case, therefore, points to the importance of histological examination of extramedullary tumors in CML for evaluation of disease status and for therapeutic decisions.     

Clinical features of Japanese type 1 autoimmune hepatitis patients with zone III necrosis

Aim: In Caucasians in northern Europe and North America, type 1 autoimmune hepatitis is characterized by susceptibility to human leukocyte antigens DR3 and DR4, and patients with zone III necrosis more frequently have an acute onset of the disease and a lower frequency of cirrhosis than those without. In Japanese patients, however, type 1 autoimmune hepatitis is primarily associated with DR4, and there are almost no DR3-positive patients. Thus, the clinical features of Japanese patients with type 1 autoimmune hepatitis and zone III necrosis may be different from those reported previously for Caucasians. Methods: We investigated 160 consecutive patients with type 1 autoimmune hepatitis (20 males and 140 females; median age, 55 years; range, 16-79 years). Results: Forty-seven patients (29%) had zone III necrosis, and these patients had lower serum levels of albumin and higher serum levels of total bilirubin, aspartate aminotransferaseand alanine aminotransferase. Histologically, zone III necrosis was found more frequently in patients with acute hepatitis than in those with chronic hepatitis. However, there was no difference in the frequency of cirrhosis between patients with and without zone III necrosis. In addition, normalization of serum alanine aminotransferase levels within six months after the introduction of corticosteroid treatment was slightly more frequent in patients with zone III necrosis (95% vs. 88%). Conclusion: In Japanese patients, zone III necrosis may reflect not only acute autoimmune hepatitis, but also acute exacerbation of pre-existing chronic disease. Furthermore, patients with zone III necrosis may respond better to corticosteroid treatment than those without.     

An experimentally-induced acute hepatic failure model in various strains of mice

When BALB/cAJcl mice are intravenously injected with heat-killedPropionibacterium acnes (P. acnes) followed by an intravenous injection of lipopolysaccharide (LPS) 7 days later, massive necrosis is induced in the liver tissue and most of the mice die within 24 hours of LPS injection. Using this experimental model, acute hepatic failure was induced in various strains of mice and the difference in the response was studied. As a result, as in BALB/cAJcl mice, acut hepatic failure was also induced in BALB/ cAJcl-nu, AKR/J, C3H/HeNJcl, C57BL/6NJcl and DDy mice. However, as an exception, hepatic cell necrosis was hardly seen and the survival rate was remarkable high in C3H/HeJ mice, which genetically do not respond to LPS stimulation. These results indicate that for this experimental induction of acute hepatic failure, macrophages must be activated by the two-step stimulation ofP. acnes and LPS.