Endothelial progenitors encapsulated in bioartificial niches are insulated from systemic cytotoxicity and are angiogenesis competent.

Intrinsic stem cells (SC) participate in tissue remodeling and regeneration in various diseases and following toxic insults. Failure of tissue regeneration is in part attributed to lack of SC protection from toxic stress of noxious stimuli, thus prompting intense research efforts to develop strategies for SC protection and functional preservation for in vivo delivery. One strategy is creation of artificial SC niches in an attempt to mimic the requirements of endogenous SC niches by generating scaffolds with properties of extracellular matrix. Here, we investigated the use of hyaluronic acid (HA) hydrogels as an artificial SC niche and examined regenerative capabilities of encapsulated embryonic endothelial progenitor cells (eEPC) in three different in vivo models. Hydrogel-encapsulated eEPC demonstrated improved resistance to toxic insult (adriamycin) in vitro, thus prompting in vivo studies. Implantation of HA hydrogels containing eEPC to mice with adriamycin nephropathy or renal ischemia resulted in eEPC mobilization to injured kidneys (and to a lesser extent to the spleen) and improvement of renal function, which was equal or superior to adoptively transferred EPC by intravenous infusion. In mice with hindlimb ischemia, EPC encapsulated in HA hydrogels dramatically accelerated the recovery of collateral circulation with the efficacy superior to intravenous infusion of EPC. In conclusion, HA hydrogels protect eEPC against adriamycin cytotoxicity and implantation of eEPC encapsulated in HA hydrogels supports renal regeneration in ischemic and cytotoxic (adriamycin) nephropathy and neovascularization of ischemic hindlimb, thus establishing their functional competence and superior capabilities to deliver stem cells stored in and released from this bioartificial niche.

Development of three different neoplasias in a patient in an 18-year period of time.

This study presents a rare case of a patient who developed three different types of neoplasia in an 18-year period of time. The case presents a 31-year-old man with a history of treated Hodgkin's lymphoma in the neck region at the age of 13 years. The patient was admitted at the General Hospital of Nafplio for differential diagnosis of pain in the right subcostal region initiated 1 month before his admission and normochromic, normocytic anaemia. The laboratory examinations lead to the diagnosis of a sarcoma in the cardioesophageal junction. The patient was subjected to total gastrectomy. Nine months later he is admitted with a palpable firm lump in the nipple of the right breast, which suggested a malignant neoplasia. The patient was subjected to modified radical mastectomy. The appearance of three different types of neoplasia in three different organ systems in the same patient and the infrequency of the specific neoplasias individually and in combination present a special interest considering the patient's genetic background and the uniqueness of the case in the international literature.

Efficacy of ibandronate for the treatment of skeletal events in patients with metastatic breast cancer.

Patients with breast carcinoma often develop bone metastases that carry a high risk of complications. A randomized, placebo-controlled trial was conducted to evaluate the efficacy and safety of ibandronate in patients with metastatic bone disease following breast cancer. The primary efficacy end point of the study was the proportion of patients who developed skeletal-related events (SREs, defined as pathologic fracture, spinal cord compression, radiation therapy to bone, change in anti-neoplastic therapy and surgery to bone). Secondary end points included time to first skeletal event, skeletal morbidity rate (events/year) and time to progression of bone lesions. In 150 patients (148 [female symbol] / 2 [male symbol]) with breast carcinoma and bone metastases, treatment with intravenous ibandronate 6 mg over 15 min every 4 weeks for 24 months significantly reduced the proportion of patients who experienced an SRE compared with placebo (36% vs. 48%; P = 0.027). Time to first SRE was also delayed significantly (median 457 vs. 304 days; P = 0.007). Multiple event analysis showed that ibandronate reduced the risk of developing an SRE by 32% (hazard ratio = 0.69; 95% confidence interval 0.42-0.79; P = 0.003). In general, ibandronate was well tolerated with very rare grade 3 or 4 toxicity. In this study, ibandronate was shown to be significantly more effective than placebo as a treatment for metastatic bone disease from breast cancer using multiple end points.

Once-weekly epoetin beta therapy in patients with solid tumours and chemotherapy-induced anaemia: a randomized, double-blind, dose-finding study.

Anaemia is common in patients receiving chemotherapy, causing symptoms that have a major impact on quality of life (QoL). Epoetin beta rapidly increases haemoglobin (Hb) levels and improves QoL in anaemic patients with a variety of tumours. This was a randomized, double-blind, parallel-group, dose-finding study assessing the efficacy and safety of once-weekly epoetin beta in patients with solid tumours receiving chemotherapy. Adult patients with anaemia (Hb < 11 g/dL) were randomized to receive epoetin beta 30,000 IU or 20,000 IU once weekly for 12 weeks. All patients received oral iron supplementation. Haemoglobin levels, transfusion need and QoL [Functional Assessment of Cancer Therapy-fatigue (FACT-F) subscale score] were assessed at regular intervals. Fifty patients were randomized; 30 patients received epoetin beta 30,000 IU once weekly and 20 received 20,000 IU once weekly. Mean (+/- SD) increase in Hb from baseline to week 12 was 1.75 +/- 2.15 g/dL in the 30,000 IU group (P = 0.008 vs. baseline) and 1.04 +/- 1.75 g/dL in the 20,000 IU group (non-significant). Haemoglobin response (increase in Hb >or=2 g/dL from baseline) was observed in 78.3% of patients receiving epoetin beta 30,000 IU and 66.7% receiving epoetin beta 20,000 IU. Improvements in FACT-F subscale score were significantly (P < 0.001) correlated with increases in Hb level. Transfusion use was low during the study in both groups. Both epoetin beta regiments were well tolerated and there were no dose-dependent adverse events. Epoetin beta 30,000 IU once weekly is an effective and well-tolerated treatment of anaemia in patients with solid tumours.

Proteins of the secretory pathway govern virus productivity during lytic gammaherpesvirus infection.

BACKGROUND: Diseases caused by gammaherpesviruses continue to be a challenge for human health and antiviral treatment. Most of the commonly used antiviral drugs are directed against viral gene products. However, the emergence of drug-resistant mutations ma limit the effectiveness of these drugs. Since viruses require a host cell to propagate, the search for host cell targets is an interesting alternative. METHODS: In this study, we infected three different cell types (fibroblasts, endothelial precursor cells and macrophages with a murine gammaherpesvirus and analysed the host cell response for changes either common to all or unique to a particular cell type using oligonucleotide microarrays. RESULTS: The analysis revealed a number of genes whose transcription was significantly up- or down-regulated in either one or two of the cell types tested. After infection, only two genes, Lman1 (also known as ERGIC53) an synaptobrevin-like 1 (sybl1) were significantly up-regulated in all three cell types, suggestive for a general role for the virus life cycl independent of the cell type. Both proteins have been implicated in cellular exocytosis and transport of glycoproteins through the secretory pathway. To test the significance of the observed up-regulation, the functionality of these proteins was modulated, and the effect on virus replication was monitored. Inhibition of either Lman1 or sybl1 resulted in a significant reduction in virus production. CONCLUSIONS: This suggests that proteins of the secretory pathway which appear to be rate limiting for virus production may represent new targets for intervention.

Ibandronate is effective in preventing skeletal events in patients with bone metastases from colorectal cancer.

Patients with metastatic colorectal carcinoma (CRC) often develop bone metastases with a high risk of complications. Ibandronate is a novel single-nitrogen bisphosphonate that has been shown to be effective for treating bone metastases from breast cancer. A randomized, placebo-controlled trial was conducted to evaluate the efficacy and safety of ibandronate in patients with bone metastases from CRC. The primary efficacy end point was the proportion of patients with skeletal-related events (defined as pathologic fracture, spinal cord compression, radiation therapy to bone, change in antineoplastic therapy or surgery to bone). Secondary end points included time to first skeletal event, skeletal morbidity rate (events/year) and time to progression of bone lesions. In 73 patients with CRC, treatment with intravenous ibandronate 6 mg administered via a 15-min infusion significantly reduced the proportion of patients with skeletal events (39% vs. 78% with placebo; P = 0.019) and prolonged the time to first event by at least 6 months (median >279 vs. 93 days with placebo; P = 0.009). Ibandronate also significantly reduced the skeletal morbidity rate (mean 2.36 vs. 3.14 with placebo; P = 0.018) and prolonged time to progression of bone lesions (214 days vs. 81 days with placebo; P = 0.018). Ibandronate was well tolerated with very rare grade 3 or 4 toxicity. Furthermore, the incidence of renal adverse events was comparable with placebo and there were no clinically relevant changes in serum creatinine. Ibandronate provided significant clinical benefits for patients with bone metastases secondary to CRC. These results indicate that ibandronate may be an effective treatment for patients with metastatic bone disease following CRC. Larger studies are required for further assessment.

Targeting the Hprt locus in mice reveals differential regulation of Tie2 gene expression in the endothelium.

To study the in vivo expression of the murine Tie2 gene, we have targeted the hypoxanthine phosphoribosyltransferase (Hprt) gene locus to generate two single-copy transgenic mice: T1, containing the 2,100-bp Tie2 promoter upstream from the beta-galactosidase (LacZ) gene, and T5, which also included an enhancing element originating from the first intron of the Tie2 gene. Comparing T1 and T5 embryos at day E10.5 revealed differential endothelial cell-specific expression of LacZ, whereas colocalization analyses showed that the expression was confined to endothelial cells. Moderate reporter gene activity was observed in the brain and kidney of T1 adults, whereas extensive LacZ gene expression was seen in the vasculature of most organs of the T5 adults. This study demonstrates the feasibility of targeting the Hprt locus with endothelial cell-specific sequences to analyze the spatial-temporal expression of transgenes. Of particular importance is the observation that the analysis of a single transgene copy in a defined locus allows for an accurate and rapid comparison of transcriptional activity among regulatory DNA sequences.

Isolation and characterization of endothelial progenitor cells from mouse embryos.

The cardiovascular system develops early in embryogenesis from cells of mesodermal origin. To study the molecular and cellular processes underlying this transition, we have isolated mesodermal cells from murine embryos at E7.5 with characteristic properties of endothelial progenitors by using a combination of stromal cell layers and growth conditions. The isolated embryonic cells displayed unlimited stem-cell-like growth potential and a stable phenotype in culture. RNA analysis revealed that the embryonic cells express the endothelial-specific genes tie-2 and thrombomodulin (TM) as well as the early mesodermal marker fgf-3. The GSL I-B4 isolectin, a marker of early endothelial cells, specifically binds to the isolated cells. The in vitro differentiation with retinoic acid and cAMP led to a 5- to 10-fold induction of flk-1, von Willebrand Factor (vWF), TM, GATA-4 and GATA-6. Electron microscopy revealed that in vitro differentiation is associated with increased amounts of rER and Golgi, and a dramatic increase in secretory vesicles packed with vWF. When cultured in Matrigel, the embryonic cells assume the characteristic endothelial cobblestone morphology and form tubes. Injection into chicken embryos showed incorporation of the embryonic cells in the endocardium and the brain vasculature. The expression of TM, tie-2, GATA-4 and GATA-6 suggests that the isolated embryonic endothelial cell progenitors are derived from the proximal lateral mesoderm where the pre-endocardial tubes form. The properties of the endothelial cell progenitors described here provide a novel approach to analyze mediators, signaling pathways and transcriptional control in early vascular development.

Temporal and spatial pattern of expression of the HDL receptor SR-BI during murine embryogenesis.

During rodent fetal development, maternal lipoproteins can be sources of cholesterol for the membrane synthesis required for tissue growth in the developing embryo and for steroid hormone production in the extraembryonic tissues. Although the mechanisms underlying the maternal-fetal lipoprotein cholesterol transport system are not well defined, the placenta and yolk sac seem to play major roles in this process, serving as functionally active interfaces between maternal circulation and the embryo. In rodents, the principal cholesterol transporter in the plasma is HDL, and the HDL receptor SR-BI is a physiologically important mediator of cholesterol uptake in adult liver and steroidogenic tissues. To begin to investigate SR-BI's role in maternal cholesterol uptake by the fetus, we used immunofluorescence microscopy to determine the pattern of SR-BI expression during murine embryogenesis. At day E7.5 in gestation, there was significant SR-BI expression in endothelial cells of the decidua, but little in intraembryonic and extraembryonic tissues. By day E8.5, there was a dramatic increase in SR-BI expression in the trophoblast cells which surround the developing embryo. Beginning at day E10, SR-BI was expressed in both the placenta and yolk sac. The expression in these extraembryonic tissues was correlated with significant uptake of fluorescent dye by the yolk sac visceral endodermal cells from DiI-labeled HDL injected into pregnant mice. Within the embryo proper, SR-BI expression appeared by day E14.5 at high levels in the adrenal gland. SR-BI expression was not detected in the embryonic liver through day E17.5 of gestation; however, it could be observed in neonatal livers. These findings suggest that SR-BI may play a role in the rodent maternal-fetal lipoprotein cholesterol transport system, supplying HDL cholesterol for either membrane or steroid hormone synthesis, or both.

A data-acquisition system for the analysis of the isometric tension generated by an electrically stimulated skeletal muscle.

The system is designed for data-acquisition and computation of a relatively large number of parameters of a single twitch or tetanic contraction generated by an electrically stimulated skeletal muscle. The parameters that can be computed using the program facilities are: (i) the rise time (Tc), 50% relaxation time (50% Tr) and the maximum tension (Pt) of the twitch contraction; (ii) the approximate number of motor units innervating the muscle and the fatigue index; (iii) the fusion frequency of the tetanic contraction and the twitch to tetanus ratio; (iv) the maximum tetanic tension (P0) and its Tc and 50% Tr; (v) the P0 versus muscle length diagram; (vi) the fatigue-time course.

Mini-Oct and Oct-2c: two novel, functionally diverse murine Oct-2 gene products are differentially expressed in the CNS.

We report that two novel alternatively spliced products of the murine Oct-2 gene encode Mini-Oct (Oct-2d), a protein consisting of almost only the POU domain, and Oct-2c, a protein lacking the last 12 amino acids of Oct-2a. Ectopic expression in HeLa cells shows that Oct-2c is a transactivator, whereas Mini-Oct fails to transactivate if the octamer motif is in a promoter position next to TATA box. Mini-Oct can repress the transcriptional signal generated by endogenous octamer factors in F9 cells. It seems that Mini-Oct has the potential to serve as a transcriptional modulator for genes regulated by different octamer-binding factors. In situ hybridization reveals that Mini-Oct expression follows the general pattern of other known Oct-2 transcripts. However, it is absent from the Purkinje cell layer in the cerebellum of adult mice, and strong expression is observed in the developing nasal neuroepithelium and primary spermatids. Differential expression patterns of the Oct-2 transcripts with different transactivation/repression capacities of the encoded proteins may have a specific role in gene expression in the developing nervous system and in adult brain.

A transcription factor interacting with the class I gene enhancer is inactive in tumorigenic cell lines which suppress major histocompatibility complex class I genes.

AKR leukemias display different amounts of major histocompatibility complex class I antigens on the cell surface. The absence of H-2Kk molecules correlates with the ability of these cell lines to form tumors in vivo as well as to escape lysis by cytotoxic T lymphocytes in vitro. In this report it is shown that the 5' regulatory area of the H-2Kk gene failed to activate transcription in H-2Kk-negative cells. Examination of the proteins interacting with the H-2Kk enhancer in expressing and nonexpressing cells revealed clear differences. In particular, the level of a nuclear protein interacting at position -166 was greatly reduced in the negative cell lines. A transcription factor, known as H2TF1 or KBF1, has been shown previously to interact with this binding site and to be essential for the expression of certain class I genes as well as the expression of beta 2-microglobulin. These results demonstrate that the molecular mechanism of class I gene suppression in malignant tumor cells is at the level of transcription and is most probably modulated by H2TF1/KBFI. In addition, it is shown that the same transcription factor is only present in mouse tissues expressing class I antigens.

Structure and expression of the mouse Oct2a and Oct2b, two differentially spliced products of the same gene.

A large family of tissue-specific nuclear proteins interact with the octamer motif ATTTGCAT, a transcriptional regulatory element found in the promoter and enhancer sequences of many genes. As a step towards elucidating the mechanism of this regulation, cDNA clones of the mouse Oct2 protein were isolated. One, called here Oct2b, encodes a larger variant of the previously described Oct2a proteins. The Oct2b cDNA has an insertion of 74 bp close to the 3' end which creates an open reading frame distinct from Oct2a. As a result, the Oct2b protein has a carboxy end which is similar to that of the ubiquitous octamer-binding protein Oct1. Analysis of the Oct2 gene shows that Oct2a and Oct2b are differentially spliced products of the same gene. The insertion in the Oct2b cDNA results from the inclusion of an additional exon in the mRNA which would otherwise reside in an intron sequence of the Oct2a transcript. RNA analysis demonstrates that both Oct2a and 2b mRNAs are most abundant in B-cells but they are also expressed in a variety of tissues including brain, intestine, testis, kidney, as well as in embryos. Interestingly, the ratio of Oct2a and 2b varies among tissues. In situ hybridization studies during mouse embryogenesis show that the Oct2 gene is widely expressed in the developing nervous system. In contrast, expression in the adult brain is confined to very specific areas which include the suprachiasmatic and medial mammillary nuclei, hippocampus, olfactory tract and the olfactory bulb. Oct2 proteins are present in both neuronal and oligodendroglial cells, although they are more abundant in glial cells.

Cell-type-specific control elements of the lymphotropic papovavirus enhancer.

Lymphotropic papovavirus (LPV) exhibits a highly restricted host range, in which only cells of primate B-lymphocyte origin are permissive for infection. Its enhancer element contributes to this tropism, since transcriptional potentiation is confined to cells of the hematopoietic lineage. Nuclear extracts from B and T cells, but not from HeLa cells, contain protein factors that interact specifically with the LPV 63-base-pair enhancer repeat, as demonstrated by DNase I footprinting and gel retardation experiments. Within the repeat three sequence motifs were identified: the core motif, the Pu box, and a novel element named T motif. Functional analysis demonstrated that these motifs as well as some sequences upstream of the repeat contribute to the optimal activity of the enhancer. There are clear differences between the patterns of binding of the B and T lymphocyte nuclear proteins to the enhancer which are also reflected in the transcriptional activity of the enhancer in both cell types. Furthermore, the activity of the LPV enhancer and its interaction with nuclear proteins seem to be regulated during B-cell differentiation.

A family of octamer-specific proteins present during mouse embryogenesis: evidence for germline-specific expression of an Oct factor.

We have analysed various adult organs and different developmental stages of mouse embryos for the presence of octamer-binding proteins. A variety of new octamer-binding proteins were identified in addition to the previously described Oct1 and Oct2. Oct1 is ubiquitously present in murine tissues, in agreement with cell culture data. Although Oct2 has been described as a B-cell-specific protein, similar complexes were also found with extracts from brain, kidney, embryo and sperm. In embryo and brain at least two other proteins, Oct3 and Oct7, are present. A new microextraction procedure allowed the detection of two maternally expressed octamer-binding proteins, Oct4 and Oct5. Both proteins are present in unfertilized oocytes and embryonic stem cells, the latter containing an additional protein, Oct6. Whereas Oct4 was not found in sperm or testis, it is expressed in male and female primordial germ cells. Therefore Oct4 expression is specific for the female germline at later stages of germ cell development. Our results indicate that a family of octamer-binding proteins is present during mouse development and is differentially expressed during early embryogenesis. Protease clipping experiments of Oct4 and Oct1 suggest that both proteins contain similar DNA-binding domains.

Octamer binding proteins confer transcriptional activity in early mouse embryogenesis.

Oct4 and Oct5 are two mouse maternally expressed proteins binding to the octamer motif. Both are found in unfertilized oocytes and embryonic stem cells, whereas Oct4 is also found in primordial germ cells. In this study, the activity of the octamer motif was analysed in two embryonic stem cell lines containing Oct4 and Oct5, the teratocarcinoma-derived cell line F9 and the blastocyst-derived cell line D3. It is known that oligomerization of the octamer motif creates a powerful B-cell specific enhancer. As shown here, this oligomerized transcriptional element is also a very strong enhancer in F9 and D3 embryonic stem cells. After differentiation of the stem cells, both enhancer activity and the amount of the octamer binding proteins decrease. An intact octamer stimulates heterologous promoters in embryonic stem cells, whereas mutations in the octamer motif abolish transcriptional stimulation and binding of the octamer factors. The use of transgenic embryos demonstrates transcriptional activation in the inner cell mass but not in the trophoblast of blastocysts. The results indicate that Oct4 and Oct5 are active early in mouse development.

Evolutionary changes in the developmental expression of silkmoth chorion genes and their morphological consequences.

Discrete changes in silkmoth choriogenesis have occurred during evolution, as exemplified in the present report in Antheraea polyphemus and Hyalophora cecropia. At the level of morphology, the chorion of A. polyphemus has surface structures, called aeropyle crowns, that are absent from H. cecropia. Aeropyle crowns form during the very late period of choriogenesis and consist of two substructures--lamellae and filler. Filler is present in H. cecropia in greatly reduced amounts. At the level of protein synthesis, overall similarities in the two species are maintained until the very late period of choriogenesis, when synthesis of aeropyle crown components is maximal. In H. cecropia, very late period-specific proteins are reduced in number and abundance. Several of these minor proteins are candidates for E1 and E2, the components of filler. E1 and E2 RNAs are about 35 times more abundant in A. polyphemus, despite very similar gene copy numbers and times of expression in the two species. These results support the hypothesis that evolutionary changes in chorion morphology have resulted from regulatory changes in the expression of chorion genes, either at the level of transcription or mRNA decay. The hypothesis that evolutionary changes in chorion morphology are based on terminal addition onto a preexisting developmental program is discussed.

Patterns of region-specific chorion gene expression in the silkmoth and identification of shared 5' flanking genomic elements.

Time-dependent and cell-specific changes in concentrations of total RNA, of poly A+ RNA, and of specific mRNAs have been measured throughout silkmoth choriogenesis. Levels of total RNA and of poly A+ RNA are maintained throughout much of choriogenesis, but decrease at least fourfold during the very late period, in parallel with a decrease in overall protein synthesis. Very late period changes in total RNA and in poly A+ RNA are less pronounced in the aeropyle crown region, where a subset of chorion proteins is preferentially synthesized, than in the flat region. Maximal accumulation of the E1 and E2 chorion mRNAs occurs preferentially in the aeropyle crown region during the very late period. Uridine pulse-labeling studies suggest that E1 and E2 transcription is similarly aeropyle crown region-specific and immediately precedes the time of maximal E1 and E2 RNA accumulation and protein synthesis. Sequences from the 5' flanking regions of E1 and E2 genes have been compared. Several oligonucleotide sequences are present in both genes, and some are duplicated. These are potential cis-acting, regulatory elements.

Organization of regionally expressed silkmoth chorion genes.

We described the organization of two silkmoth chorion genes, called E1 and E2, whose expression is largely restricted in time to the very late period of choriogenesis and in space to one of two major subpopulations of follicle cells. Using E1 and E2 clone cDNAs as probes, we showed that gene copy numbers per haploid genome remain constant throughout silkmoth development despite major changes in total DNA content per nucleus. Furthermore, gene copy numbers are the same in both cellular regions of the choriogenic follicle despite differences in nuclear size and levels of E gene expression. Southern analysis indicated between two and four copies each for E1 and E2 genes. Analysis of chromosomal clones showed that single copies of E1 and E2 are separated by about 7.5 kilobases and are transcribed from the same DNA strand. Two distinct pairs of cloned E1 and E2 genes were characterized. No other chorion genes were in their immediate vicinity.