Proliferation and differentiation of myelodysplastic CD34+ cells: phenotypic subpopulations of marrow CD34+ cells

In a search for a mechanism to explain the impaired growth of progenitor cells in patients with myelodysplastic syndromes (MDS), marrow CD34+ cells were purified up to 94.9% +/- 4.2% for normal individuals and 88.1% +/- 17.6% for MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). Phenotypic subpopulations of these CD34+ cells were analyzed for CD38, HLA-DR, CD33, CD13, CD14, CD41 and CD3 plus CD19, in association with proliferative and differentiative capacities. The 15 studies performed included 12 MDS patients. Coexpression rate of CD13 significantly increased in the MDS CD34+ cell population with a value of 91.4% +/- 11.6% and ranging from 60.3% to 100%, and exceeded 99% in four studies, whereas that of normal CD34+ cells was 49.9% +/- 15.8%, ranging from 28.2% to 70.1% (P < .001). Coexpression rate of CD38, HLA-DR, CD33, CD14, and CD3 plus CD19 in MDS CD34+ cells did not significantly differ from that of normal CD34+ cells. The total number of colonies and clusters grown from 100 normal marrow CD34+ cells was 40.4 +/- 8.6, the range being from 27.2 to 50.3; this varied in MDS marrow CD34+ cells with a value of 34.0 +/- 28.7, the range being 0 to 95.9. The lineage of colonies and clusters promoted by MDS marrow CD34+ cells was predominantly committed to nonerythroid with impaired differentiation in 13 of 15 studies (87%). CD13 is first expressed during hematopoiesis by colony-forming unit granulocyte-macrophage and is absent in erythroid progenitors. Therefore, this study provides direct evidence for the lineage commitment of MDS CD34+ cells to nonerythroid with impaired differentiation and explains the mechanism of nil or low colony expression of MDS progenitor cells to erythroid lineage.     

Postoperative plasma cortisol levels predict long-term outcome in patients with Cushing's disease and determine which patients should be treated with pituitary irradiation after surgery

Transsphenoidal surgery is the treatment of choice for ACTH-producing pituitary adenoma (Cushing's disease) and pituitary irradiation is widely considered the most appropriate treatment for patients with Cushing's disease for whom transsphenoidal surgery has been unsuccessful. We studied 49 consecutive patients who underwent transsphenoidal surgery for the treatment of Cushing's disease at Tokyo Women's Medical University from 1977-1997 with a mean follow-up duration of 87.6 months (range, 24-253 months). We examined the relationship between postoperative endocrinological data, assessed between 3 and 8 weeks after surgery, and long-term outcome and efficacy of pituitary irradiation after surgery. Long-term remission was defined as the regression of the symptom and signs of Cushing's syndrome, and restoration of normal levels of plasma ACTH, cortisol and urinary free cortisol, together with adequate suppression of morning plasma cortisol levels following the administration of low dose (1 mg) of dexamethasone. Thirty patients had no additional treatment after pituitary surgery. Only 1 of 25 patients (4%) whose postoperative plasma cortisol level was less than 2 microg/dl developed recurrent disease whereas 3 out of 5 patients with postoperative plasma cortisol levels higher than 2 microg/dl relapsed. Postoperative external pituitary radiation was used to treat the remaining 19 patients. Four patients who received radiation therapy had a low or undetectable postoperative plasma cortisol level (<2 microg/dl, 56 nmol/L) and all of these patients developed hypopituitarism whereas 5 patients with subnormal plasma cortisol levels (2.0-10.0 microg/dl) remained in remission. Among 10 patients with persistent disease after surgery, 6 entered remission 6-47 months after irradiation but one of them subsequently relapsed after 108 months. These results suggest that 1) additional therapy should be avoided in patients with a postoperative plasma cortisol less than 2 microg/dl because relapse is very rare and radiotherapy will frequently induce hypopituitarism, 2) patients with a subnormal cortisol level following surgery should be treated with pituitary irradiation, because the relapse rate is reportedly high and radiotherapy is effective in preventing relapse, 3) radiotherapy in patients with persistent disease after surgery is effective only in 50% (5/10) of the patients.     

Cardioprotection during the final stage of the late phase of ischemic preconditioning is mediated by neuronal NO synthase in concert with cyclooxygenase-2

The infarct-sparing effect of the late phase of ischemic preconditioning (late PC) lasts for 72 hours. Upregulation of both cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS) has been shown to be essential to the protection in the initial stage of late PC (24 hours after PC); however, the mechanisms underlying the protection in the final stage of late PC (48 to 72 hours after PC) are unknown. Conscious rabbits were preconditioned with six cycles of 4-minute coronary occlusion/4-minute reperfusion. At 72 hours after PC, powerful protection against infarction was associated with increased myocardial levels of COX-2 mRNA, protein, and cardioprotective prostaglandins (PGI2 and PGE2). The COX-2-selective inhibitor NS-398 completely blocked the protection. Surprisingly, iNOS expression was not increased at 72 hours; instead, upregulation of neuronal NO synthase (nNOS) was evident at both the mRNA (+266+/-20%, P<0.005) and the protein levels (+195+/-66%, P<0.005), which was accompanied by an increase in myocardial nitrite/nitrate (+20+/-4%, P<0.05). The nNOS-selective inhibitors N-propyl-l-arginine or S-ethyl N-[4-(trifluoromethyl)phenyl]isothiourea completely blocked the protection of late PC at 72 hours, whereas the iNOS-selective inhibitor S-methylisothiourea had no effect. In line with these findings, the disappearance of protection at 120 hours after PC was associated with the return of nNOS mRNA, protein, and activity to control levels. Although expression of COX-2 protein was still elevated at 120 hours, only a marginal increase in PGI2 and PGE2 levels was detected. In contrast to 72 hour after PC, nNOS was not upregulated at 24 hour after PC. We conclude that (1) the cardioprotection observed in the final stage of late PC (72 hour) is mediated by nNOS, not by iNOS, in concert with COX-2, and (2) nNOS-derived NO is required to drive COX-2 activity. These data identify, for the first time, a cardioprotective role of nNOS and demonstrate, surprisingly, that the mechanism of late PC differs at 72 hours (nNOS) versus 24 hours (iNOS).     

Characterization and subcellular localization of KCNQ1 with a heterozygous mutation in the C terminus

Numerous mutations in KCNQ1, a gene encoding the alpha -subunit of cardiac delayed rectifier potassium channels, have been found in long QT syndrome (LQTS). Among them, several mutations in the C terminus have been shown to cause autosomal recessive or subclinical autosomal dominant LQTS. Here, we report a heterozygous mutation, T587M, which is also in the KCNQ1 C-terminal domain. The same mutation was found in three independent probands that were clearly symptomatic with family history of cardiac sudden death. Functional assay using a heterologous expression system with a mammalian cell line (COS7 cells) revealed that the mutant displayed neither functional channels when expressed alone nor dominant-negative effect when co-expressed with wild-type (WT) KCNQ1. To examine the cellular trafficking of KCNQ1, green fluorescent protein (GFP) was tagged to the cytoplasmic C terminus of WT or mutant KCNQ1. This procedure did not affect the essential properties of expressed WT KCNQ1 channels. On confocal microscopic images, GFP-tagged WT KCNQ1 showed a plasma membrane fluorescence pattern, whereas the GFP-tagged mutant showed a perinuclear fluorescence pattern. Co-expression of the mutant with GFP-tagged WT KCNQ1 did not influence its normal cellular transport. Therefore, the T587M mutant cannot traffic to the plasma membrane and may form no subunit assembly with WT KCNQ1. These findings provide a novel molecular basis for the clinical finding that this C-terminal mutation produced a severe form of RWS-type LQTS.     

Aortic dissection with pseudo-aortic regurgitation and transient myocardial ischemia--a case report

Aortic dissection causes acute aortic regurgitation in one half to two thirds of cases, which is due, mainly, to dilatation of the aortic root. The unsupported intimal flap prolapse, which crosses the aortic valve, rarely produces aortic regurgitation. Moreover, transient myocardial ischemia rarely occurs by malperfusion, which might be due to compression of the ostium of the coronary artery by the false lumen or by the intimal flap. The authors had a rare case of aortic dissection with "pseudo-'aortic regurgitation; ie, regurgitation flow existed just in the area surrounding the intimal flap during diastole and produced transient myocardial ischemia. In this case, the swinging motion of the intimal flap through the aortic valve caused pseudoaortic regurgitation and transient myocardial ischemia, which should be repaired by emergency surgical procedure. Surgery was successful and saved the patient's life.     

Development of severe aplastic anemia in a girl with Hashimoto's thyroiditis and papillary thyroid carcinoma

A 14-year-old girl was admitted because of general fatigue and cervical lymphadenopathy. She showed bilateral struma (IInd degree) and enlargement of her left cervical lymph nodes. Laboratory data revealed neutropenia (219/microliter) and thrombocytopenia (Plt 5.1 x 10(4)/microliter) with mild anemia (Hb 11.1 g/dl), and the bone marrow aspirate and biopsy specimens showed hypocellularity. In addition, auto-antibodies against thyroid peroxidase (TPO) and thyroglobulin (TG) were highly elevated. Computed tomography of the neck showed a nodule in the left thyroid lobe with marked lymphadenopathy, and fine needle aspiration biopsy demonstrated papillary thyroid carcinoma with Hashimoto's thyroiditis and metastasis to the lymph nodes. One month after left thyroid lobectomy and cervical lymphadenectomy, the patient's condition progressed to very severe aplastic anemia, and she received immunosuppressive therapy consisting of cyclosporin A and anti-thymocyte globulin. Hematologically, partial and complete responses were obtained three and six months later, respectively. Of interest, anti-TPO and TG antibody titers remarkably decreased after immunosuppressive therapy. The patient had HLA-DR 2(DRB 1*1501) and DR 8(DRB 1*0802). The former is frequently found in patients with cyclosporin A-dependent aplastic anemia, and the latter is frequently found in Asian patients with Hashimoto's thyroiditis, suggesting an underlying autoimmune background for the simultaneous outbreak of aplastic anemia and Hashimoto's thyroiditis complicated by thyroid carcinoma.     

Changes in the expression of collapsin response mediator protein‐2 during synaptic plasticity in the mouse hippocampus

We have previously reported that nicotine application to the adult mouse causing long‐term potentiation‐like facilitation in vivo in the hippocampus can serve as a model of synaptic plasticity. The present study clarifies the involvement of collapsin response mediator protein‐2 (CRMP2) in synaptic plasticity. CRMP2 was detected in hippocampal neurons of adult mice. The levels of CRMP2 mRNA and protein were increased 2–24 hr and 4–24 hr, respectively, after application of nicotine (3 mg/kg, i.p.), finally returning to the basal level by 48 hr. Furthermore, the ratio of phosphorylated CRMP2 (pCRMP2) at Thr514 residue, an inactive form, to total CRMP2 levels was not changed during synaptic plasticity expressed by nicotine, indicating an enhanced level of non‐pCRMP2. This increase of CRMP2 was inhibited by blockade of nicotinic acetylcholine receptors (nAChRs) and required activation of both α4β2 and α7 nAChRs. Although the level of ubiquitinated CRMP2 was increased 8 hr after nicotine treatment, the ratio of ubiquitinated CRMP2 to total CRMP2 protein was similar for nicotine‐treated and nontreated mice. This study demonstrates that the expression of CRMP2 increases in hippocampal neurons during synaptic plasticity and that the increment is due mainly to mRNA expression. We propose that CRMP2, particularly non‐pCRMP2, could contribute to long‐lasting synaptic plasticity. © 2015 Wiley Periodicals, Inc.     

Loss of sorting nexin 5 stabilizes internalized growth factor receptors to promote thyroid cancer progression

Thyroid carcinoma is the most common endocrine malignancy and its prevalence has recently been increasing worldwide. We previously reported that the level of sorting nexin 5 (Snx5), an endosomal translocator, is preferentially decreased during the progression of well‐differentiated thyroid carcinoma into poorly differentiated carcinoma. To address the functional role of Snx5 in the development and progression of thyroid carcinoma, we established Snx5‐deficient (Snx5 ^?/?) mice. In comparison to wild‐type (Snx5 ^+/+) mice, Snx5 ^?/? mice showed enlarged thyroid glands that consisted of thyrocytes with large irregular‐shaped vacuoles. Snx5 ^?/? thyrocytes exhibited a higher growth potential and higher sensitivity to thyroid‐stimulating hormone (TSH). A high content of early endosomes enriched with TSH receptors was found in Snx5 ^?/? thyrocytes, suggesting that loss of Snx5 caused retention of the TSH receptor (TSHR) in response to TSH. Similar data were found for internalized EGF in primary thyrocytes. The increased TSH sensitivities in Snx5 ^?/? thyrocytes were also confirmed by results showing that Snx5 ^?/? mice steadily developed thyroid tumors with high metastatic potential under high TSH. Furthermore, a thyroid cancer model using carcinogen and an anti‐thyroidal agent revealed that Snx5 ^?/? mice developed metastasizing thyroid tumors with activation of MAP kinase and AKT pathways, which are postulated to be major pathways of malignant progression of human thyroid carcinoma. Our results suggest that thyrocytes require Snx5 to lessen tumorigenic signaling driven by TSH, which is a major risk factor for thyroid carcinoma. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.