Delta-like 4 is indispensable in thymic environment specific for T cell development

The thymic microenvironment is required for T cell development in vivo. However, in vitro studies have shown that when hematopoietic progenitors acquire Notch signaling via Delta-like (Dll)1 or Dll4, they differentiate into the T cell lineage in the absence of a thymic microenvironment. It is not clear, however, whether the thymus supports T cell development specifically by providing Notch signaling. To address this issue, we generated mice with a loxP-flanked allele of Dll4 and induced gene deletion specifically in thymic epithelial cells (TECs). In the thymus of mutant mice, the expression of Dll4 was abrogated on the epithelium, and the proportion of hematopoietic cells bearing the intracellular fragment of Notch1 (ICN1) was markedly decreased. Corresponding to this, CD4 CD8 double-positive or single-positive T cells were not detected in the thymus. Further analysis showed that the double-negative cell fraction was lacking T cell progenitors. The enforced expression of ICN1 in hematopoietic progenitors restored thymic T cell differentiation, even when the TECs were deficient in Dll4. These results indicate that the thymus-specific environment for determining T cell fate indispensably requires Dll4 expression to induce Notch signaling in the thymic immigrant cells.

Expression of Delta-like 1 in the splenic non-hematopoietic cells is essential for marginal zone B cell development

The Notch ligand Delta-like 1 (Dll1) is critical for the generation of marginal zone (MZ) B cells in the spleen. However, the precise mechanism underlying the differentiation of MZB cells is unclear. To determine whether hematopoietic cells or non-hematopoietic cells provides the Dll1-mediated signals to primitive hematopoietic cells, we transplanted lineage(-)c-kit(+)Sca-1(+) (KSL) bone marrow cells derived from wild-type (Dll1(+/+)) GFP-transgenic mice into lethally irradiated Dll1 conditional knockout (cKO) mice. After transplantation, we examined the kinetics of hematopoietic reconstitution and found that although the frequency of stem/progenitor subsets and of more mature lymphoid, myeloid, and erythroid lineages were normal, the donor-derived hematopoietic cells failed to differentiate into MZB cells. We further demonstrated that while the splenic stromal cells of wild-type mice expressed Dll1 molecule, the splenic stromal cells of recipient Dll1 cKO mice deleted the expression of Dll1. These results suggesting that the expression of Dll1 in splenic non-hematopoietic stromal cells, but not hematopoietic cells, is essential for the development of MZB cells.

Primary retroperitoneal mucinous cystadenocarcinoma associated with pregnancy

Primary retroperitoneal mucinous cystadenocarcinoma (PRMC) is an extremely rare tumor. Only 30 cases have been reported previously in the English literature, and little information is available concerning its treatment and prognosis. The patient was a 28-year-old woman, presenting with a right mid-abdominal tumor at 26 weeks of gestation. At 31 weeks of gestation, she underwent an exploratory laparotomy and was diagnosed with a PRMC. No disseminated tumor was observed, and an excision of only the tumor was performed. She had an uneventful vaginal delivery at 38 weeks of gestation and remains free of disease at 13 months after the operation. This report describes a case of PRMC associated with pregnancy. The optimal management of these retroperitoneal masses during pregnancy is discussed. Based on limited experience and the current literature, a PRMC with an intact capsule and no dissemination appears to have a good prognosis and can be treated by tumor excision alone in patients who wish to preserve fertility

Humanizing bone marrow in immune-deficient mice

Humanized mice are useful for studying human hematopoietic stem cells (HSCs) and their niche. In particular, clonal study of human HSC enables precise comparison of in vivo behavior between murine and human HSCs. A single HSC is able to reconstitute hematopoiesis even after serial transplantations in mice. While the life span of somatic cells is over that of individual in mice, this is not the case in humans. Clonal studies of human HSCs clearly demonstrated their aging in hosts. Since murine studies have demonstrated that HSCs are protected from aging by their niche in bone marrow, the humanizing niche model will reveal the precise mechanism by which human HSCs are protected from exhaustion in vivo. Direct transplantation of human mesenchymal stem cells into mouse bone marrow results in reconstitution of the functional human hematopoietic microenvironment comprised of pericytes, myofibroblasts, reticular cells, osteocytes in bone, bone-lining osteoblasts, and endothelial cells. These humanized mouse models are essential for testing whether the insights on hematopoiesis from mouse studies are applicable to humans before clinical application.

Angiopoietin-1 supports induction of hematopoietic activity in human CD34- bone marrow cells

OBJECTIVE

Hematopoietic stem cells (HSCs) consist of heterogenous subpopulations, one of which is CD34(-) HSCs. Recent development of successful engraftment by intra-bone marrow transplantation revealed severe combined immunodeficiency (scid) mouse-repopulating cell (SRC) activity in human CD34(-) cord blood (CB) cells. On the other hand, CD34(-) cells from bone marrow (BM) cells remain relatively undefined. Here, we investigated pre-SRC populations in human BM CD34(-) cells and the effect of the niche-related factor, angiopoietin-1, on them.

METHODS

Two populations in BM CD34(-) cells (namely M cells and S cells) were purified by flow cytometry. Then, they were cocultured with six growth factors on the hematopoietic-supportive mouse BM stromal cell line, HESS-5 or AHESS-5 that were engineered to produce human angiopoietin-1, because we detected Tie2 expression on M cells and S cells. Cultured cells were assessed for their in vitro and in vivo hematopietic activities.

RESULTS

After 7 days in coculture, AHESS-5 was stronger more effective than HESS-5 in converting M and S cells to CD34(+) cells (M cells: 67.4% vs 17.5%, n =6, p < 0.001) (S cells: 42.3% vs 2.3%, n = 6, p < 0.001). Furthermore, both M and S cells were able to engraft in immunodeficient mice after they were cocultured on AHESS-5.

CONCLUSIONS

Results suggest that angiopoietin-1 supports SRC activities in human CD34(-) BM cells, as murine studies demonstrated. Furthermore, identification of previously undetected subpopulations of BM CD34(-) HSCs unveils heterogenous components in the stem cell pool.

Prediction of myometrial invasion in patients with endometrial carcinoma: comparison of magnetic resonance imaging, transvaginal ultrasonography, and gross visual inspection

This study evaluated the accuracy of magnetic resonance imaging (MRI) and transvaginal ultrasonography (TVUS) in preoperative detection of myometrial invasion by endometrial cancer. We also evaluated the results of gross visual inspection (GVI) of surgical specimens compared with histopathological diagnosis. One hundred and seventy-seven women underwent preoperative pelvic MRI, TVUS, and intraoperative GVI. Myometrial tumor invasion was evaluated histologically and classified as absent (depth a), superficial (depth b: < or = 50% invasion), or deep (depth c: > 50% invasion). The accuracy of MRI, TVUS, and GVI were 64.0, 66.9, and 63.8%, respectively. The positive predictive values of of each modality for depth a were 52.6, 51.4, and 52.2%, respectively. The accuracy of each in detecting deep myometrial invasion (depth c) were 84.0, 86.9, 83.1%. Although evaluation of depth a was limited with all modalities, MRI and TVUS were shown to be reliable for preoperative evaluation of deep myometrial invasion. The high accuracy of these three methods suggests that they are useful either interchangeably or in combination.

Clonal analysis of thymus-repopulating cells presents direct evidence for self-renewal division of human hematopoietic stem cells

To elucidate the in vivo kinetics of human hematopoietic stem cells (HSCs), CD34+CD38– cells were infected with lentivirus vector and transplanted into immunodeficient mice. We analyzed the multilineage differentiation and self-renewal abilities of individual thymus-repopulating clones in primary recipients, and their descending clones in paired secondary recipients, by tracing lentivirus gene integration sites in each lymphomyeloid progeny using a linear amplification-mediated polymerase chain reaction (PCR) strategy. Our clonal analysis revealed that a single human thymus-repopulating cell had the ability to produce lymphoid and myeloid lineage cells in the primary recipient and each secondary recipient, indicating that individual human HSCs expand clonally by self-renewal division. Furthermore, we found that the proportion of HSC clones present in the CD34+ cell population decreased as HSCs replicated during extensive repopulation and also as the differentiation capacity of the HSC clones became limited. This indicates the restriction of the ability of individual HSCs despite the expansion of total HSC population. We also demonstrated that the extensive self-renewal potential was confined in the relatively small proportion of HSC clones. We conclude that our clonal tracking studies clearly demonstrated that heterogeneity in the self-renewal capacity of HSC clones underlies the differences in clonal longevity in the CD34+ stem cell pool.

Radiation myelopathy after radioactive iodine therapy for spine metastasis

A case of radiation myelopathy after radioactive iodine therapy is reported. This is the first report to describe radiation myelopathy after I-131 therapy. A 62-year-old female with spinal metastasis of T10 received I-131 therapy. She presented with radiation myelopathy 34 months after the irradiation. We need to recognize the possibility of this serious complication even in the case of I-131 therapy. There is a risk of radiation myelopathy even after I-131 therapy, especially in cases with spinal cord compression such as this.

Expression of CD90 on keratinocyte stem/progenitor cells

BACKGROUND

The identification and purification of keratinocyte stem cells (KSCs) that are capable of self-renewal and maintenance of differentiating cell populations could contribute both to our understanding of the biology of these cells, and to significant clinical applications, such as the culturing of keratinocytes for transplantation to severe burn wounds. Here, we report the detection of CD90(+) cells in cultured normal human epidermal keratinocytes and adult skin.

OBJECTIVES

To investigate the biological function of CD90(+) and CD90(-) keratinocytes.

METHODS

CD90(+) and CD90(-) keratinocytes were purified from adult skin and cultured keratinocytes using fluorescent activated cell sorting, and their biological abilities were analysed using both in vitro and in vivo assays.

RESULTS

Flow cytometry (FCM) analysis identified approximately 18% of post-primary neonatal keratinocytes as CD90(+). However, during expansion of the culture, the expression level of CD90 rapidly decreased to about 2.5% at passage 10, while most of the keratinocytes maintained expression of alpha6 integrin. Purified CD90(+) keratinocytes demonstrated a sixfold higher cell growth rate than CD90(-) cells and the ability to form large (over 3 mm in diameter) colonies. We then quantitatively evaluated both populations using a previously described in vivo human epidermal cyst formation assay. Enhanced green fluorescent protein (EGFP)-labelled CD90(+) or CD90(-) keratinocytes were subcutaneously injected into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Six weeks after transplantation, EGFP(+) cell clusters in human epidermal cysts were evaluated using image analysis software. EGFP(+) cell cluster areas in the basal layer, derived from EGFP(+) CD90(+) cells, were eightfold larger than clusters of EGFP(+) CD90(-) cells. Furthermore, immunohistochemical staining and FCM analysis indicated that CD90 was expressed in most of the basal layer of the normal human epidermis.

CONCLUSIONS

These results indicated that CD90 is a useful marker for the detection of human KSC-enriched populations in cultured human keratinocytes.

Reconstitution of the functional human hematopoietic microenvironment derived from human mesenchymal stem cells in the murine bone marrow compartment

Hematopoiesis is maintained by specific interactions between both hematopoietic and nonhematopoietic cells. Whereas hematopoietic stem cells (HSCs) have been extensively studied both in vitro and in vivo, little is known about the in vivo characteristics of stem cells of the nonhematopoietic component, known as mesenchymal stem cells (MSCs). Here we have visualized and characterized human MSCs in vivo following intramedullary transplantation of enhanced green fluorescent protein-marked human MSCs (eGFP-MSCs) into the bone marrow (BM) of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. Between 4 to 10 weeks after transplantation, eGFP-MSCs that engrafted in murine BM integrated into the hematopoietic microenvironment (HME) of the host mouse. They differentiated into pericytes, myofibroblasts, BM stromal cells, osteocytes in bone, bone-lining osteoblasts, and endothelial cells, which constituted the functional components of the BM HME. The presence of human MSCs in murine BM resulted in an increase in functionally and phenotypically primitive human hematopoietic cells. Human MSC-derived cells that reconstituted the HME appeared to contribute to the maintenance of human hematopoiesis by actively interacting with primitive human hematopoietic cells.

Direct evidence for ex vivo expansion of human hematopoietic stem cells

To characterize human hematopoietic stem cells (HSCs), xenotransplantation techniques such as the severe combined immunodeficiency (SCID) mouse repopulating cell (SRC) assay have proven the most reliable methods thus far. While SRC quantification by limiting dilution analysis (LDA) is the gold standard for measuring in vitro expansion of human HSCs, LDA is a statistical method and does not directly establish that a single HSC has self-renewed in vitro. This would require a direct clonal method and has not been done. By using lentiviral gene marking and direct intra-bone marrow injection of cultured CD34+ CB cells, we demonstrate here the first direct evidence for self-renewal of individual SRC clones in vitro. Of 74 clones analyzed, 20 clones (27%) divided and repopulated in more than 2 mice after serum-free and stroma-dependent culture. Some of the clones were secondary transplantable. This indicates symmetric self-renewal divisions in vitro. On the other hand, 54 clones (73%) present in only 1 mouse may result from asymmetric divisions in vitro. Our data demonstrate that current ex vivo expansion conditions result in reliable stem cell expansion and the clonal tracking we have employed is the only reliable method that can be used in the development of clinically appropriate expansion methods.

Long-term conservative therapy for endometrial adenocarcinoma in young women

BACKGROUND

To evaluate the efficacy and safety of long-term conservative therapy with medroxyprogesterone acetate (MPA) for endometrial carcinoma in young patients who had experienced failure after initial therapy or relapse, we reviewed the clinical and pathologic records of eight patients diagnosed with well-differentiated endometrial adenocarcinoma without myometrial invasion who were treated with MPA for over 6 months because of treatment failure or relapse.

RESULTS

The average duration of MPA treatment was 22 months. All patients were followed-up for a mean of 76.5 months. Seven patients responded to initial MPA treatment within a period of 14 months (mean, 7.9 months). All these patients experienced relapse and the mean time to relapse was 11.6 months (range, 4-33 months). All six patients with relapse were treated with additional treatments of MPA, and all but one responded to this treatment within a period of 16 months (mean, 8.0 months). Six patients ultimately underwent hysterectomy. All presented well-differentiated endometrioid adenocarcinomas without extrauterine disease. Three became pregnant and two delivered full-term normal infants. No patient died of the disease.

CONCLUSION

Although lesions are expected to disappear with prolonged MPA treatment, this form of progestin therapy is hazardous because recurrence occurs frequently. Only strictly selected patients should therefore be indicated for long-term MPA treatment and careful evaluation before and after treatment should be performed.

Complete response to docetaxel and carboplatin combination chemotherapy for a stage IV uterine papillary serous carcinoma: a case report

We report a case of a stage IV uterine papillary serous carcinoma (UPSC) with multiple organ metastases. The patient was treated with docetaxel and carboplatin combination chemotherapy. After five courses, uterine tumor, Douglas tumor, lymphadenopathy, and distant metastases on magnetic resonance imaging or computed tomography scan were completely resoluted. Moreover, endometrial biopsy showed no carcinoma tissues after six courses. We suggest that this regimen may be effective for treatment of advanced-stage UPSC.

Association between single nucleotide polymorphisms of estrogen receptor alpha gene and efficacy of HRT on bone mineral density in post-menopausal Japanese women

BACKGROUND

Although HRT for post-menopausal women can protect against bone loss, variations in bone responses exist. We studied whether single nucleotide polymorphisms (SNP) of the estrogen receptor-alpha (ERalpha) gene contribute to the effect of HRT on lumbar spine bone mineral density (BMD).

METHODS

Subjects were 84 post-menopausal women who had been taking HRT for 3 years to treat osteopenia or osteoporosis. Eighteen SNP in the ERalpha gene were characterized by a single nucleotide primer extension assay.

RESULTS

Genotyping of the 84 individuals revealed that all SNP were quite common, the minor allele frequency being > or = 20%. A SNP in intron 6 (IVS6+14144) was significantly associated with the response to HRT for the first 3 years after starting treatment (P = 0.043, 0.025 and 0.032 for the first, second and third years respectively). Haplotype analysis revealed that a combination of SNP IVS6+14144 and IVS4+4238 was significantly correlated with the response to HRT; women with haplotype G-G (IVS6 14144-IVS4 4238) showed a significantly higher response (P = 0.014, 0.043 and 0.010 for the first second and third year respectively).

CONCLUSIONS

These results suggest that a specific SNP and the haplotype of the selected SNP could be used to predict the effect of HRT on lumbar BMD.

Placental site trophoblastic tumor presenting as subaponeurotic metastasis

Cases of metastatic placental site trophoblastic tumor (PSTT) have a very poor prognosis because these tumors tend to be less sensitive to chemotherapy than other types of gestational trophoblastic disease. We describe the case of a 25-year-old woman who presented with occipital tumor and abnormal vaginal bleeding. Hysterectomy, bilateral salpingo-oophorectomy, and occipital tumor removal revealed a primary PSTT in the uterus, with ovarian and occipital subaponeurotic metastases. She received etoposide, methotrexate, actinomycin-D/cyclophosphamide, vincristine chemotherapy and had a complete clinical remission. Fifteen months later, she had a recurrent subaponeurotic occipital tumor invading the cranium and underwent tumor removal along with cranial bone followed by local irradiation. She was then treated with etoposide, cis-platinum/etoposide, methotrexate, actinomycin-D chemotherapy and again had a remission for 5 months. The patient, however, had a left parietal subaponeurotic tumor, invading the dura mater, and received local irradiation. Soon after, she developed left orbital bone metastasis, treated by local irradiation. These bone metastases responded to the radiation completely. However, multiple organ metastases were found, and she died of the disease. This represents the first case of PSTT with initial subaponeurotic metastasis in a living patient. New modalities of treatment for high-risk or metastatic PSTT need to be developed.

Cytoplasmic and mitochondrial Ca2+ levels in brown adipocytes

AIM

We elucidated the mitochondrial functions of brown adipocytes in intracellular signalling, paying attention to mitochondrial activity and noradrenaline- and forskolin-induced Ca(2+) mobilizations in cold-acclimated rats.

METHODS

A confocal laser-scanning microscope of brown adipocytes from warm- or cold-acclimated rats was employed using probes rhodamine 123 which is a mitochondria-specific cationic dye, and the cytoplasmic and mitochondrial Ca(2+) probes fluo-3 and rhod-2. X-ray microanalysis was also studied.

RESULTS

The signal of rhodamine 123 in the cells was decreased by antimycin A which effect was less in cold-acclimated cells than warm-acclimated cells. Cytoplasmic and mitochondrial Ca(2+) in cold-acclimated brown adipocytes double-loaded with fluo-3 and rhod-2 were measured. Noradrenaline induced the rise in cytoplasmic Ca(2+) ([Ca(2+)](cyto)) followed by mitochondrial Ca(2+) ([Ca(2+)](mito)), the effect being transformed into an increase in [Ca(2+)](cyto) whereas a decrease in [Ca(2+)](mito) by antimycin A or carbonyl cyanide m-chlorophenylhydrazone (CCCP). Antimycin A induced small Ca(2+) release from mitochondria. CCCP induced Ca(2+) release from mitochondria only after the cells were stimulated with noradrenaline. Further, forskolin also elicited an elevation in [Ca(2+)](cyto) followed by [Ca(2+)](mito) in the cells. The Ca measured by X-ray microanalysis was higher both in the cytoplasm and mitochondria whereas K was higher in the mitochondria of cold-acclimated cells in comparison to warm-acclimated cells.

CONCLUSIONS

These results suggest that noradrenaline and forskolin evoked an elevation in [Ca(2+)](cyto) followed by [Ca(2+)](mito), in which H(+) gradient across the inner membrane is responsible for the accumulation of calcium on mitochondria. Moreover, cAMP also plays a role in intracellular and mitochondrial Ca(2+) signalling in cold-acclimated brown adipocytes.

Placental site trophoblastic tumor presenting as subaponeurotic metastasis

Cases of metastatic placental site trophoblastic tumor (PSTT) have a very poor prognosis because these tumors tend to be less sensitive to chemotherapy than other types of gestational trophoblastic disease. We describe the case of a 25-year-old woman who presented with occipital tumor and abnormal vaginal bleeding. Hysterectomy, bilateral salpingo-oophorectomy, and occipital tumor removal revealed a primary PSTT in the uterus, with ovarian and occipital subaponeurotic metastases. She received etoposide, methotrexate, actinomycin-D/cyclophosphamide, vincristine chemotherapy and had a complete clinical remission. Fifteen months later, she had a recurrent subaponeurotic occipital tumor invading the cranium and underwent tumor removal along with cranial bone followed by local irradiation. She was then treated with etoposide, cis-platinum/etoposide, methotrexate, actinomycin-D chemotherapy and again had a remission for 5 months. The patient, however, had a left parietal subaponeurotic tumor, invading the dura mater, and received local irradiation. Soon after, she developed left orbital bone metastasis, treated by local irradiation. These bone metastases responded to the radiation completely. However, multiple organ metastases were found, and she died of the disease. This represents the first case of PSTT with initial subaponeurotic metastasis in a living patient. New modalities of treatment for high-risk or metastatic PSTT need to be developed

Competitive Repopulation Assay of Two Gene-Marked Cord Blood Units in NOD/SCID/γcnull Mice

In multiunit cord blood transplantation, hematopoietic stem cells from each unrelated cord blood (UCB) unit competitively reconstitute the hematopoietic system in a recipient. To evaluate the fate of the progeny of each UCB unit and to determine the effects of graft-versus-graft reaction, we established a novel competitive repopulation assay using NOD/SCID/gammac(null) mice in which human T lymphocytes develop from CD34+ cells. CD34+ cells from each UCB unit were labeled with recombinant lentivirus vectors carrying genes encoding either enhanced green fluorescent protein (EGFP) or enhanced yellow fluorescent protein (EYFP). Hematopoietic chimerism composed of both EGFP+ and EYFP+ cells was stably maintained up to 6 months after transplantation with purified CD34+ cells; the ratio of EGFP+ to EYFP+ cells in peripheral blood and bone marrow posttransplantation was equivalent to the ratio of these cells at transplantation. However, when mononuclear cells from two UCB units were cotransplanted with CD34+ cells, engraftment was highly competitive, with cells from only one or the other of the two UCB units surviving. Further subfractionations of mononuclear cells indicate that the skewed chimerism that is often observed in clinical multiunit cord blood transplantation may be mediated by the cooperation of both CD4+ and CD8+ T cells. The assay established here will be a useful tool for analyzing hematopoietic reconstitution in clinical multiunit cord blood transplantation.