Evaluation of telomerase activity in non-genital Bowen's disease.

We investigated the level of telomerase activity (TA) in 17 specimens of non-genital Bowen's disease (BD) and in 14 specimens of skin without sun exposure (non-exposed skin) using a non-isotopic PCR-based telomeric repeat amplification protocol (TRAP) assay. Expression of human telomerase reverse transcriptase (hTERT; the catalytic subunit of telomerase) was also evaluated by immunochemistry in the non-genital BD tissues. Moderate to high levels of TA were detected in 41.2% of 17 non-genital BD specimens (P = 0.001). In contrast, TA was not evident in non-exposed skin. Recently, nucleolin was reported to be associated with hTERT, so we used this antibody instead of hTERT antibody. Immunohistochemistry showed that nucleolin expression was associated with high TA levels in non-genital BD. Our results also revealed differences of TA levels among non-genital BD specimens. High levels of TA in those specimens were not age related. Five out of 7 specimens (71.4%) with moderate to high TA levels were from sun-exposed sites, while the remaining 10 specimens with low levels of TA were from non-exposed sites. These results suggested that cellular DNA damage caused by ultraviolet irradiation might be associated with an increase of TA in non-genital BD. Among non-genital BD specimens, 4 out of 17 (23.5%) showed high levels of TA (median relative TA value: 79.8%; P = 0.003), which might be associated with immortalization or transformation to invasive squamous cell carcinoma.

[Successful emergency surgery for acute mitral regurgitation due to total rupture in the anterior papillary muscle after acute myocardial infarction; report of a case].

A 32-year-old male was admitted with dyspnea Severe dyspnea and hypoxemia developed the next day and blood examination indicated acute myocardial infarction. Echocardiogram revealed massive mitral regurgitation with prolapse of the anterior mitral leaflet due to rupture in the papillary muscle. Percutaneous coronary intervention for total occlusion in the right coronary artery was successfully performed, but progressive heart failure continued to develop. Surgery for the papillary muscle rupture was performed on the 3rd day. Complete head rupture of the anterior papillary muscle was found and the mitral valve was replaced with a prosthetic valve (St. Jude Medical valve: #31). Pathological findings showed necrosis in the papillary muscle with inflammatory changes. The postoperative course was uneventful and the patient was discharged on the 43rd day after surgery.

Telomeric DNA in normal and leukemic blood cells.

We studied telomeric DNA in leukemic cells as well as in normal T cells, B cells, monocytes, polymorphonuclear leukocytes, and bone marrow hematopoietic progenitor cells. No marked differences were observed in the sizes of the telomeric repeats in the various populations of normal blood cells obtained from donors in their twenties to sixties, and the telomere length ranged between 8.5 and 9.0 kb. The leukemic cells of 12 patients with acute leukemia (seven with myeloid and five with lymphoid leukemia) showed a variable reduction in the length of telomeric DNA, ranging from 2.7 to 6.4 kb. The average telomere length was 4.8 and 4.7 kb in myeloid and lymphoid leukemia, respectively, while the telomere length in peripheral blood mononuclear cells obtained from the same patients during complete remission was 8.5 and 7.9 kb, respectively. When the same Southern blots were hybridized with Alu or alphoid sequences, no marked changes in the sizes of the repetitive DNA sequences were observed, indicating that the DNA abnormality in the leukemic cells was specific to the telomere region. Investigation of telomeric DNA changes may be helpful in determining the biological properties of leukemic cells.

Modulation of neutrophil function by lysozyme. Potential negative feedback system of inflammation.

Host responses to infectious organisms should be modulated so that tissue-damaging products of inflammatory cells do not produce excessive destruction of normal tissue. Lysozyme, which is continuously secreted by monocytes, which, in turn, migrate relatively late to inflammatory areas, was found to significantly dampen several responses of neutrophils to inflammatory stimulants. Thus, human lysozyme obtained and purified from the urine of patients with monocytic leukemia (but not its structurally similar and comparably cationic analogue, eggwhite lysozyme) depresses chemotaxis of normal neutrophils to activated complement, bacterial supernate, and N-formylmethionyl-phenylalanine. In addition, human (but not eggwhite) lysozyme depresses oxidative metabolism (hexose monophosphate shunt activity) and superoxide generation of neutrophils. The specificity of the suppressive effects was indicated by inhibition studies with rabbit antihuman lysozyme antibody, and with the trisaccharide of N-acetylglucosamine, a specific inhibitor of lysozyme. The results suggest that lysozyme, a product of inflammatory cells themselves, may function in a negative feedback system to modulate the inflammatory response.

Abnormal adherence of sickle erythrocytes to cultured vascular endothelium: possible mechanism for microvascular occlusion in sickle cell disease.

The abnormal shape and poor deformability of the sickled erythrocyte (RBC) have generally been held responsible for the microvascular occlusions of sickle cell disease. However, there is no correlation between the clinical severity of this disease and the presence of sickled RBC. In searching for additional factors that might contribute to the pathophysiology of sickle cell disease, we have investigated the possibility that sickle RBC might be less than normally repulsive of the vascular endothelium. After RBC suspensions are allowed to settle onto plates of cultured human endothelial cells, normal RBC are completely removed by as few as six washes. In contrast, sickle RBC remain adherent despite multiple washes. On subconfluent culture plates, normal RBC are distributed randomly, whereas sickle RBC cluster around endothelial cells. Sickle RBC adherence is not enhanced by deoxygenation but does increase with increasing RBC density. The enzymatic removal of membrane sialic acid greatly diminishes the adherence of sickle RBC to endothelial cells, suggesting that sialic acid participates in this abnormal cell-cell interaction. Although net negative charge appears normal, sickle RBC mainfest an abnormal clumping of negative surface charge as demonstrated by localization of cationized ferritin. These abnormalities are reproduced in normal RBC loaded with nonechinocytogenic amounts of calcium. We conclude that sickle RBC adhere to vascular endothelial cells in vitro, perhaps caused by a calcium-induced aberration of membrane topography. This adherence may be a pathogenetic factor in the microvascular occlusions characteristic of sickle cell disease.

Identification and cornification-related gene expression of canine keratinocyte differentiation-associated protein, Kdap.

The outermost layer of skin, the epidermis, is cornified epithelial tissue composed of keratinocytes. To maintain the structure and function of the epidermis, the regulation of proliferation, differentiation, and cornification of keratinocytes is crucial, and various soluble factors secreted by keratinocytes are involved in these regulations. Previously, work has shown that keratinocytes secreted the protein Kdap (keratinocyte differentiation-associated protein) associated with the formation of cornified cell envelopes, a specialized protective barrier structure on the periphery of terminally differentiating keratinocytes. In the present report, the canine counterpart of human Kdap is identified and an attempt has been made to define its physiological role in canine keratinization. Canine Kdap (cKdap) showed structural features commonly observed in other counterparts and is secreted from transfected cells. The expression profile of cKdap mRNA, which was restrictively expressed in cornified epithelial tissues besides skin has also been determined. These findings indicate that there is a strong association between cKdap expression and cornification, which supports previous observations that Kdap is involved in the synthesis and/or degradation of cornified cell envelopes in humans and mice.

Estrogen receptors in human myeloma cells.

It has recently been reported that the human myeloma cell line U266 proceeds to undergo apoptosis after cultivation with the antiestrogen tamoxifen, thus raising the possibility that antiestrogens may be candidates for use in myeloma therapy. To obtain basic information on the effects of antiestrogens on myeloma cells, we investigated the mRNA expression levels of estrogen receptor (ER)-alpha, ER-beta, and coactivators and corepressors in nine human myeloma cell lines and compared them with those of seven human breast cancer cell lines including four ER-positive and three ER-negative lines. The alterations in cell growth and mRNA expression of the target genes of ER or those of cytokines in the myeloma lines by estradiol or antiestrogens (tamoxifen and toremifene) were also investigated. In addition, effects on membrane Fas expression, appearance of apoptosis, and cell cycle perturbation were analyzed. It was revealed that ER-beta and corepressors were dominantly expressed in myeloma cells, and antiestrogens induced growth inhibition through apoptosis mediated by a Fas-related pathway and G1 arrest of the cell cycle in myeloma cell lines.

Deficiency in WT1-targeting microRNA-125a leads to myeloid malignancies and urogenital abnormalities.

The Wilms' tumor gene WT1 is overexpressed in leukemia and solid tumors and has an oncogenic role in leukemogenesis and tumorigenesis. However, precise regulatory mechanisms of WT1 overexpression remain undetermined. In the present study, microRNA-125a (miR-125a) was identified as a miRNA that suppressed WT1 expression via binding to the WT1-3'UTR. MiR-125a knockout mice overexpressed WT1, developed myeloproliferative disorder (MPD) characterized by expansion of myeloid cells in bone marrow (BM), spleen and peripheral blood, and displayed urogenital abnormalities. Silencing of WT1 expression in hematopoietic stem/progenitor cells of miR-125a knockout MPD mice by short-hairpin RNA inhibited myeloid colony formation in vitro. Furthermore, the incidence and severity of MPD were lower in miR-125a (-/-) mice than in miR-125a (+/-) mice, indicating the operation of compensatory mechanisms for the complete loss of miR-125a. To elucidate the compensatory mechanisms, miRNA array was performed. MiR-486 was occasionally induced in compete loss of miR-125a and inhibited WT1 expression instead of miR-125a, resulting in the cancellation of MPD occurrence. These results showed for the first time the post-transcriptional regulatory mechanisms of WT1 by both miR-125a and miR-486 and should contribute to the elucidation of mechanisms of normal hematopoiesis and kidney development.

Up-regulation of telomerase activity in human lymphocytes.

We detected telomerase activity in human lymphocytes obtained from normal donors. Telomerase was up-regulated within 24 h when peripheral blood mononuclear cells were cultured in the presence of phytohemagglutinin. The activity increased gradually over 72 h, then remained stable for 96 h. During this period, cell number and the length of telomeric DNA remained constant. Anti-CD3 monoclonal antibody and Pansolbin also induced telomerase activity. These results demonstrate that telomerase is regulated during lymphocyte activation as cells progress from G0 to S phase. This system is useful for the study of telomerase during carcinogenesis, and in the testing of telomerase-inhibitory drugs.

Severely impaired cardiac autonomic nervous activity after the Fontan operation.

BACKGROUND: Elevated neurohumoral activity and an abnormal cardiopulmonary response to exercise are well-established characteristics in patients after the Fontan operation. However, there have been few studies addressing cardiac autonomic nervous activity (CANA) in these patients. METHODS AND RESULTS: We evaluated CANA in 63 post-Fontan patients and 44 controls. Cardiac parasympathetic nervous activity (PSNA) was estimated by heart rate (HR) changes after cholinergic blockade, HR variability, and arterial baroreflex sensitivity. Cardiac sympathetic nervous activity was estimated by the heart to mediastinum [(123)I]metaiodobenzylguanidine activity ratio (H/M) and the HR increase (DeltaHR) after isoproterenol infusion (beta). DeltaHR and peak oxygen uptake (VO(2)) were measured by exercise test. There was no difference in beta between the Fontan group and controls. PSNA and H/M were markedly lower than in controls (P<0.001). PSNA and beta were related to DeltaHR (P<0.05); however, peak VO(2) was not correlated with DeltaHR. Neither PSNA nor H/M was associated with clinical features, including hemodynamics, type of repair, number of surgical procedures, age at Fontan operation, or follow-up period, and administration of an angiotensin-converting enzyme inhibitor did not improve the impaired CANA in these patients. CONCLUSIONS: After the Fontan procedure, postsynaptic beta-sensitivity is maintained and is important in DeltaHR during exercise as is PSNA, although DeltaHR does not determine exercise capacity. The lack of a relationship between CANA and clinical features implies that, in addition to surgical damage, the Fontan circulation per se may impair CANA. Angiotensin-converting enzyme inhibitor administration does not change this abnormality.

Human urinary macrophage colony-stimulating factor reduces the incidence and duration of febrile neutropenia and shortens the period required to finish three courses of intensive consolidation therapy in acute myeloid leukemia: a double-blind controlled study.

PURPOSE: To determine whether macrophage colony-stimulating factor (M-CSF) reduces the incidence and duration of febrile neutropenia during three courses of intensive consolidation therapy and whether it shortens time to complete consolidation therapy. PATIENTS AND METHODS: In 198 adult patients with acute myeloid leukemia (AML) in complete remission (CR), M-CSF (8 x 10(6) U/d) or placebo was administered from 1 day after the end of each consolidation chemotherapy for 14 days. RESULTS: The duration and incidence of febrile neutropenia was significantly reduced by 34% (P = .00285) and 17% (P = .02065), respectively, in 88 assessable patients in the M-CSF group compared with those in 94 assessable patients in the placebo group. Patients in the M-CSF group had 565 days and 133 episodes of febrile neutropenia during 7,901 days at risk, while patients in the placebo group had 977 days and 185 episodes during 9,077 days at risk. The median period required to finish the three courses of consolidation therapy was 93 days in the M-CSF group, which was significantly shorter than 110 days in placebo group (P = .0050). In the M-CSF group, the recovery of neutrophils and platelets was significantly faster (P = .0348 and P = 0.0364, respectively), the administration of systemic antimicrobial agents tended to be less (P = .0839), and the frequency of platelet transfusion (P = .0259) and the total volume of transfused platelets (P = .0292) were significantly less. However, there was no significant difference in the disease-free survival. CONCLUSION: M-CSF significantly reduced the incidence and duration of febrile neutropenia during the intensive consolidation therapy, and shortened the time to complete consolidation chemotherapy in AML.

Analysis of prognostic factors in newly diagnosed acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy. Japan Adult Leukemia Study Group.

PURPOSE: We conducted a multicenter study of differentiation therapy with all-trans retinoic acid (ATRA) followed by intensive chemotherapy in patients with newly diagnosed acute promyelocytic leukemia (APL) and analyzed the prognostic factors for predicting complete remission (CR), event-free survival (EFS), and disease-free survival (DFS). PATIENTS AND METHODS: All patients received ATRA until CR. If patients had an initial leukocyte count greater than 3.0 x 10(9)/L, they received daunorubicin (DNR) and behenoyl cytarabine (BHAC). During therapy, if patients showed blast and promyelocyte counts greater than 1.0 x 10(9)/L, they received additional DNR and BHAC. After achieving CR, patients received three courses of consolidation and six courses of maintenance/intensification chemotherapy. RESULTS: Of 198 registered, 196 were assessable (age range, 15 to 86 years; median, 46) and 173 (88%) achieved CR. Multivariate analysis showed that no or minor purpura at diagnosis (P = .0046) and age less than 30 years (P = .0076) were favorable factors for achievement of CR. Predicted 4-year overall survival and EFS rates were 74% and 54%, respectively, and the 4-year predicted DFS rate for 173 CR patients was 62%. Multivariate analysis showed that age less than 30 years (P = .0003) and initial leukocyte count less than 10 x 10(9)/L (P = .0296) were prognostic factors for longer EFS, and initial leukocyte count less than 10.0 x 10(9)/L was a sole significant prognostic factor for longer DFS (P = .0001). CONCLUSION: Our results show that age, hemorrhagic diathesis, and initial leukocyte count are prognostic factors for APL treated with ATRA followed by intensive chemotherapy.

Randomized trials between behenoyl cytarabine and cytarabine in combination induction and consolidation therapy, and with or without ubenimex after maintenance/intensification therapy in adult acute myeloid leukemia. The Japan Leukemia Study Group.

PURPOSE: We analyzed complete remission (CR), disease-free survival (DFS), and event-free survival (EFS) rates in two groups of patients treated with either N4-behenoyl-1-beta-D-arabinosylcytosine (BHAC) or cytarabine, and analyzed DFS with or without ubenimex, a biologic response modifier. PATIENTS AND METHODS: Newly diagnosed patients with acute myeloid leukemia (AML) were randomized to receive either BHAC or cytarabine as remission-induction combination chemotherapy and two courses of consolidation therapy. After maintenance/intensification therapy, patients in CR were randomized to receive either ubenimex and no drug. RESULTS: Of 341 patients registered, 326 were assessable. The age of assessable patients ranged from 15 to 82 years (median, 48). The overall CR rate was 77%: 72% in the BHAC group and 81% in the cytarabine group, and there was a significant difference between the two groups (P = .035, chi 2 test). The predicted 55-month EFS rate of all patients was 30%: 23% in the BHAC group and 35% in the cytarabine group, with a significant difference between groups (P = .0253). The predicted 55-month DFS rate of all CR patients was 38% and that of CR patients less than 50 years of age was 47%. There was no significant difference in DFS between the ubenimex group and the group that did not receive ubenimex. CONCLUSION: Analyses of our clinical trial showed that the use of BHAC in remission-induction therapy and in consolidation therapy resulted in poorer CR and EFS rates in adult AML patients compared with the use of cytarabine at the doses and schedules tested. Immunotherapy with ubenimex after the end of all chemotherapy did not improve DFS.

Influence of ventricular morphology on aerobic exercise capacity in patients after the Fontan operation.

OBJECTIVES: This study investigated the influences of ventricular morphology, hemodynamics and clinical findings on exercise capacity in patients after the Fontan operation. BACKGROUND: Determinants of exercise capacity after the Fontan operation remain unclear. METHODS: Peak oxygen uptake (PVo2) was determined in 105 patients by exercise test and compared to hemodynamics and clinical findings. Patients were divided into three groups based on ventricular morphology: those with a right ventricle (group RV), a biventricle (group BV) and a left ventricle (group LV). RESULTS: Ten patients with atrioventricular valve regurgitation (AVVR) or hypoxia exhibited a low PVo2. After excluding these patients, although PVo2 did not correlate with hemodynamics, except ventricular ejection fraction (p < 0.02), it correlated with age at the Fontan operation and exercise test (p < 0.002). The PVo2 was higher in group LV (63+/-9%) than in groups RV (55+/-9%) and BV (55+/-12%) (p < 0.01), while an inverse correlation between PVo2 and age at operation was demonstrated only in group RV (p < 0.05). Groups RV or BV and age at exercise test were associated with a lower PVo2, whereas group LV was an independent predictor of a higher PVo2 (p < 0.01). During 4.2 years of follow-up, a decrease in peak heart rate was related to a decrease in PVo2 (p < 0.05). The PVo2 decreased in group RV (p < 0.01). CONCLUSIONS: In addition to AVVR, hypoxia, and heart rate response, ventricular morphology is related to exercise capacity. Early Fontan operation may be beneficial in terms of exercise capacity, especially in the group RV patients.

Immunophenotypic features and configuration of immunoglobulin genes in hairy cell leukemia-Japanese variant.

Immunophenotypes and Ig gene rearrangements were investigated in 12 patients with a variant form of hairy cell leukemia (HCL) termed HCL-Japanese variant (HCL-J), and in an HCL-J-derived cell line. The leukemic cells of HCL-J characteristically showed the phenotype of CD20+, CD5-, CD10-, CD11c+, CD22+, CD24- and CD25-. Ig light (L) chain was undetected in nine cases, and the remaining four cases expressed kappa chain. Expression of Ig heavy (H) chain was studied in nine cases. In addition to Igkappa+ cases showing expression of predominantly gamma H chain isotype, alpha chain was detected in one case without expression of L chain. Rearranged bands in Ig heavy chain (JH) genes were recognized in all 12 cases tested. Rearranged bands in kappa chain genes and germline configuration in chi chain genes were seen in all three Igkappa+ cases tested. Four of nine cases without expression of L chain had a rearranged chi chain gene. The other three cases had chi chain genes in the germline configuration and rearranged and/or deleted kappa chain genes. In the remaining two cases, no rearrangement in either kappa or chi chain genes was detected. The Ig gene configuration and expression in HCL-J, partially overlapping with those described for immature B cell leukemia, were dissociated from the cytological features and CD20+, membrane CD22+ phenotype characteristic of mature B cells.

In vitro excess ammonia production in human myeloma cell lines.

It is well known that cases with multiple myeloma reveal various clinical manifestations such as pancytopenia, hyperproteinemia, renal dysfunction, bone lesions, hypercalcemia and immunodeficiency. Recently, a few more clinical features associated with myeloma, such as salivary type hyperamylasemia and elevated serum C-reactive protein (CRP) concentration, have been reported. The elevation of CRP is thought to be related to interleukin-6 (IL-6) production by myeloma cells, because of identification of IL-6 as an autocrine and/or paracrine growth factor for myeloma cells. More recently, there have been several reports of cases with myeloma associated with hyperammonemia. This hyperammonemia is not considered to be due to liver dysfunction, because in most of these cases tests revealed normal hepatic function, and some cases showed different patterns of serum amino acid distribution than that associated with hepatic failure. However, there have been no apparent observations of ammonia production by myeloma cells. In this study, we used six human myeloma cell lines including KMS-18, which was recently established from a myeloma case associated with hyperammonemia. These lines were treated with MRA (mycoplasma removal agent) to observe ammonia production in vitro. They produced and released significantly higher levels of ammonia into culture medium than non-myeloma hematological cell lines or the HepG2 human hepatic carcinoma cell line. Although attempts to analyze the relative expression levels of the enzymes related to ammonia biosynthesis using the reverse transcriptase-polymerase chain reaction assay failed to detect any differences between these myeloma lines and other cell lines, in vitro excess ammonia production by the myeloma cells was confirmed and the relevance to clinical manifestations is discussed.

Ectopic expression of c-myc fails to overcome downregulation of telomerase activity induced by herbimycin A, but ectopic hTERT expression overcomes it.

Telomerase plays a key role in the maintenance of chromosomal stability in tumors, but the mechanism regulating telomerase activity is still unclear. Recent studies have suggested that c-myc may be vital for regulation of hTERT mRNA expression and telomerase activity. In this study, we investigated the changes of telomerase activity and telomerase-related genes induced by herbimycin A in K562 human chronic myelogeous leukemic cells. Telomerase activity showed a biphasic pattern in herbimycin A-treated K562 cells. Initially, the telomerase activity decreased along with the decline of cells in S and G2/M phases, but it recovered slightly at the end of treatment. Expression of mRNA for the telomerase catalytic subunit (hTERT) was decreased before the decline of telomerase activity, and increased slightly before the reactivation of telomerase activity. During herbimycin A treatment, both c-myc and cyclin D1 mRNA showed transient downregulation before the increase of G1 cells. Herbimycin A treatment caused the downregulation of both telomerase activity and hTERT mRNA in cyclin D1-transfected K562 cells, while telomerase activity was partially restored in c-Myc-transfected cells. In contrast, hTERT-transfected K562 cells maintained a high level of telomerase activity during herbimycin A treatment. Neither the template RNA component of telomerase (hTERC) nor telomerase-associated protein (TEP-1) were altered in any of the transfected K562 cells. These results indicate that telomerase activity is mainly regulated by hTERT, and that c-Myc protein is one of the positive regulators of hTERT in leukemic cells but is not enough to counteract the downregulation of telomerase activity by herbimycin A completely.

Laboratory findings and clinical courses of 33 patients with granular lymphocyte-proliferative disorders.

The hematological and immunological findings and clinical courses of 33 patients (13 male, 20 female; median age at presentation, 60 years) with granular lymphocyte-proliferative disorders (GLPD) are presented. Based on the surface phenotypes of peripheral blood granular lymphocytes (GL), the GLPD were divided into CD3+ T cell-lineage GLPD (T-GLPD) and CD3- CD16+ natural killer (NK) cell-lineage GLPD (NK-GLPD). Twenty-one patients had T-GLPD, and 12 had NK-GLPD. One patient with T-GLPD and two patients with NK-GLPD had progressive clinical courses and died of the disease despite receiving combination chemotherapy. Twelve patients with T-GLPD were found to have severe anemia at presentation or during the course of the disease; four of them fulfilled the diagnostic criteria of pure red cell aplasia, and the others had closely related conditions. Six of these 12 patients were treated with cyclophosphamide, and all responded to the treatment. In 16 patients, the clinical course was stable, and spontaneous regression was observed in two patients. Since some of the patients with NK-GLPD had stable clinical courses while some had progressive clinical courses, clinical findings in these two groups were compared. We found, taking into consideration our cases and those reviewed in the literature, that age less than 40 years, fever, lymph node swelling, hepatosplenomegaly, and GL with CD16(Leu-11)-CD56+CD57- phenotype and low or absent antibody-dependent cellular cytotoxicity seemed to be predictors of a progressive clinical course.

Canine epidermal langerhans cells express alpha and gamma but not beta chains of high-affinity IgE receptor.

Epidermal Langerhans cells (LC) express a high-affinity receptor for IgE (FcepsilonRI), consisting of two chains (alpha and gamma chains) in humans that allows LC to perform Fc receptor-mediated uptake of allergens. We found that canine LC express alpha and gamma chains but not beta chain of FcepsilonRI, identical to human but not to mouse LC, which do not express functional FcepsilonRI (only gamma chain is expressed). This finding indicates that canine LC have FcepsilonRI-mediated function similar to or identical to human LC, raising the possibility that canine species provides a better model than mouse to understand the pathogenesis of human atopic dermatitis and investigate the therapeutic effect of drugs.

Late expression of red cell membrane protein 4.2 in normal human erythroid maturation with seven isoforms of the protein 4.2 gene.

The expression of protein 4.2 in normal human erythroid cells was studied utilizing erythroblasts from bone marrow and erythroid cells cultured by the two-phase liquid culture method from burst-forming unit erythroid (BFU-E) in peripheral blood. As opposed to spectrin, which was expressed in erythroid progenitors or very early erythroblasts, protein 4.2 was first detected in late erythroblasts with a morphology nearly identical to orthochromatic erythroblasts. Among the various major membrane proteins, the expression of protein 4.2 was the latest. At the gene level, protein 4.2 gene mRNA was expressed in early erythroblasts. During normal erythroid maturation, the expression of seven different protein 4.2 gene products was observed by Southern blot analysis. These seven gene products appeared to be derived from protein 4.2 gene in the presence or absence of skipping of the 90 bp in exon 1, exon 3, and/or exon 5, as judged by deduction from the protein 4.2 sequence. Therefore, it can be speculated that protein 4.2 is expressed after the cytoskeletal network has been constructed and assembled with integral proteins in the membrane lipid bilayer.