SEARCH · PubMed Health

Results for “ASC”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed2004

Adipogenic differentiation by adipose-derived stem cells harvested from GFP transgenic mice-including relationship of sex differences.

We have previously demonstrated that adipose-derived stromal cells (ASCs) as well as bone marrow-derived stromal cells (BSCs) differentiate into a variety of cell lineages both in vitro and in vivo. Both types are considered to include mesenchymal stem cells. Taking advantage of homogeneously marked cells from green fluorescent protein (GFP) transgenic mice, we have also previously reported the plasticity of BSCs and ASCs. In this study, we focused on adipogenic differentiation in vitro by ASCs harvested from GFP transgenic mice. Moreover, preadipocytes and mature adipocytes were harvested at the same time, and the cells were cultured to compare them with ASCs. Inguinal fat pads from GFP transgenic mice were used for the isolation of ASCs, preadipocytes, and mature adipocytes. After expansion to three passages of ASCs, the cells were incubated in an adipogenic medium for two weeks. Adipogenic differentiation of ASCs was assessed by Oil Red O staining and the expression of the adipocyte specific peroxisome proliferative activated receptor gamma2 (PPAR-gamma2) gene. These ASCs stained positively, and expression of PPAR-gamma2 was detected. Moreover, we also tried to characterize the influence of sex differences on the adipogenic differentiation of ASCs harvested from both male and female mice. This was assessed by the expression levels of the PPAR-gamma2 gene using real-time PCR. The results showed that the expression levels of ASCs harvested from female mice were a maximum of 2.89 times greater than those harvested from male mice. This suggests that the adipogenic differentiation of ASCs is closely related to sex differences.

Adipose Tissue↗

PubMed2004

Antibody production directed against pneumococci by immunocytes in the adenoid surface secretion.

OBJECTIVE: In previous studies of the adenoid surface secretion we revealed the presence of activated T cells, granulocytes engaged in phagocytosis and immunocytes that produce IgG, IgA and IgM. In the present study the objective was to assess the ability of these immunocytes to produce antibodies directed at S. pneumoniae. METHOD: Nine children subjected to adenoidectomy due to adenoid hypertrophy, secretory otitis media or recurrent otitis media were enrolled in the study. Samples of adenoid surface secretion were obtained by an imprint method and for comparison samples of adenoid tissue and peripheral blood were also obtained as well as a nasopharyngeal culture. Double-colour enzyme-linked immunospot (ELISPOT) assays were performed to detect total and pneumococci-specific IgG- and IgA-antibody secreting cells (ASC). In the adenoid tissue, the presence of H. influenzae type b specific ASC was also examined. RESULTS: ASC were present in all nine samples of adenoid surface secretion with a dominance of IgG-ASC as compared to IgA-ASC. The proportion of ASC relative to the total number of lymphocytes was always greater in the secretion than in the corresponding adenoid tissue. The adenoid surface secretion samples from three of nine children contained IgG-ASC directed against S. pneumoniae. IgG-ASC directed against S. pneumoniae were detected in six of eight adenoids and IgA-ASC directed against S. pneumoniae were detected in two of eight adenoids. IgA-ASC directed against H. influenzae type b (Hib) were detected in one of seven adenoids. CONCLUSION: The immunocytes in the adenoid surface secretion and the adenoid tissue itself hold the property to produce antibodies specific for known pathogens of the upper airways. These ASC are probably engaged in the immunologic defence of the nasopharyngeal mucosa and further studies are therefore called upon.

Adenoids↗

PubMed2004

Modulation by colostrum-acquired maternal antibodies of systemic and mucosal antibody responses to rotavirus in calves experimentally challenged with bovine rotavirus.

The effect of colostral maternal antibodies (Abs), acquired via colostrum, on passive protection and development of systemic and mucosal immune responses against rotavirus was evaluated in neonatal calves. Colostrum-deprived (CD) calves, or calves receiving one dose of pooled control colostrum (CC) or immune colostrum (IC), containing an IgG1 titer to bovine rotavirus (BRV) of 1:16,384 or 1:262,144, respectively, were orally inoculated with 105.5 FFU of IND (P[5]G6) BRV at 2 days of age. Calves were monitored daily for diarrhea, virus shedding and anti-BRV Abs in feces by ELISA. Anti-rotavirus Ab titers in serum were evaluated weekly by isotype-specific ELISA and virus neutralization (VN). At 21 days post-inoculation (dpi), all animals were euthanized and the number of anti-BRV antibody secreting cells (ASC) in intestinal and systemic lymphoid tissues were evaluated by ELISPOT. After colostrum intake, IC calves had significantly higher IgG1 serum titers (GMT=28,526) than CC (GMT=1195) or CD calves (GMT<4). After BRV inoculation, all animals became infected with a mean duration of virus shedding between 6 and 10 days. However, IC calves had significantly fewer days of diarrhea (0.8 days) compared to CD and CC calves (11 and 7 days, respectively). In both groups receiving colostrum there was a delay in the onset of diarrhea and virus shedding associated with IgG1 in feces. In serum and feces, CD and CC calves had peak anti-BRV IgM titers at 7 dpi, but IgA and IgG1 responses were significantly lower in CC calves. Antibody titers detected in serum and feces were associated with circulation of ASC of the same isotype in blood. The IC calves had only an IgM response in feces. At 21 dpi, anti-BRV ASC responses were observed in all analyzed tissues of the three groups, except bone marrow. The intestine was the main site of ASC response against BRV and highest IgA ASC numbers. There was an inverse relationship between passive IgG1 titers and magnitude of ASC responses, with fewer IgG1 ASC in CC calves and significantly lower ASC numbers of all isotypes in IC calves. Thus, passive anti-BRV IgG1 negatively affects active immune responses in a dose-dependent manner. In ileal Peyer's patches, IgM ASC predominated in calves receiving colostrum; IgG1 ASC predominated in CD calves. The presence in IC calves of IgG1 in feces in the absence of an IgG1 ASC response is consistent with the transfer of serum IgG1 back into the gut contributing to the protection of the intestinal mucosa.

Animals↗

PubMed2000

Inhibition of topoisomerase II by the marine alkaloid ascididemin and induction of apoptosis in leukemia cells.

Ascididemin (ASC) is a pentacyclic DNA-intercalating agent isolated from the Mediterranean ascidian Cystodytes dellechiajei. This marine alkaloid exhibits marked cytotoxic activities against a range of tumor cells, but its mechanism of action remains poorly understood. We investigated the effects of ASC on DNA cleavage by human topoisomerases I and II. Relaxation assays using supercoiled DNA showed that ASC stimulated double-stranded cleavage of DNA by topoisomerase II, but exerted only a very weak effect on topoisomerase I. ASC is a conventional topoisomerase II poison that significantly promoted DNA cleavage, essentially at sites having a C on the 3' side of the cleaved bond (-1 position), as observed with etoposide. The stimulation of DNA cleavage by topoisomerase I in the presence of ASC was considerably weaker than that observed with camptothecin. Cytotoxicity measurements showed that ASC was even less toxic to P388 leukemia cells than to P388CPT5 cells resistant to camptothecin. In addition, the marine alkaloid was found to be equally toxic to HL-60 leukemia cells sensitive or resistant to mitoxantrone. It is therefore unlikely that topoisomerases are the main cellular targets for ASC. This alkaloid was found to strongly induce apoptosis in HL-60 and P388 leukemia cells. Cell cycle analysis showed that ASC treatment was associated with a loss of cells in the G1 phase accompanied with a large increase in the sub-G1 region. Cleavage experiments with poly(ADP-ribose) polymerase (PARP) revealed that caspase-3 was a mediator of the apoptotic pathway induced by ASC. The DNA of ASC-treated cells was severely fragmented. Collectively, these findings indicate that ASC is a potent inducer of apoptosis in leukemia cells.

Alkaloids↗

PubMed2000

Influence of Drought-Induced Water Stress on Soybean and Spinach Leaf Ascorbate-Dehydroascorbate level and Redox Status.

We examined the influence of water stress (water deficit) induced by drought on the steady state levels of ascorbic acid (ASC), dehydroascorbate (DHA), and the ASC&rcolon;DHA redox status in leaflets of Glycine max (soybean) and leaves of Spinacia oleracea (spinach). Two soybean cultivars (cv. Essex and cv. Forrest) and one spinach cultivar (cv. Nordic) were grown in high-light growth chambers ( approximately 1000-1200 µmol m-2 s-1) or in the greenhouse during May, June, and July 1999. The cultivars were supplied with water until approximately 25-29 d postemergence, at which time one-half of the plants were not watered for a period of from 4.5 to 7.5 d; the other half of the plants were provided water daily and served as controls. On designated days, leaf water potential (PsiLeaf) was measured, and leaf disks of constant area were excised in the period between approximately 1230 and 1330 hours. Leaf disk samples were immediately frozen in liquid N2, samples were extracted, and ASC and DHA levels were measured and expressed as µmol per gram dry mass per time point. For the soybean cultivars, low PsiLeaf values ( approximately -3.00 to -3.95 MPa) were accompanied by slight decreases in ASC levels and slight increases in DHA levels per gram dry mass. In some cases, leaflet ASC levels of water-stressed soybeans were similar to controls or were even increased by as much as 1.2 times. In soybeans, the mole fraction of ASC remained at 93-99 mol% of the total ascorbate (ASC+DHA), indicating that most of the total ascorbate remained in the reduced form even at low water potential. In spinach plants subjected to water stress (-1.8 to -2.6 MPa), leaf ASC decreased as much as 38%, but the ASC remained at 96-99 mol% of the total ascorbate. It is concluded that during water stress, enzymes of the ascorbate-glutathione cycle in leaf mesophyll cells, as well as in the system that generates reductant to support DHA to ASC recycling, e.g., photosynthetic electron transport in chloroplasts, is able to remain active enough to maintain reduction of DHA to ASC.

Journal Article↗

PubMed1998

Antibody-secreting cells specific for simian immunodeficiency virus antigens in lymphoid and mucosal tissues of immunized macaques.

OBJECTIVES: To examine whether the route of immunization affects the induction of antibody-secreting cells (ASC) in the circulation of macaques. The distribution of ASC in the rectal mucosa and lymphoid tissues following challenge with simian immunodeficiency virus (SIV) was investigated. DESIGN: Macaques were immunized with recombinant SIV gp120 and p27 antigens by the targeted iliac lymph node (TILN) route of immunization or the nasal and rectal route, augmented by intramuscular immunization [naso-rectal intramuscular (NRI)]. The macaques were challenged with live SIV by the rectal route and ASC were assayed in the circulation before and after SIV challenge, and in the tissues removed at post-mortem. METHODS: ASC were examined in the circulation by Elispot assay. Mononuclear cells were prepared from peripheral blood, iliac and axillary lymph nodes and spleen. Rectal tissue was treated by enzyme digestion to elute mononuclear cells. RESULTS: TILN and NRI immunization induced circulating IgA and IgG ASC to both gp120 and p27. Following rectal challenge with SIV, TILN macaques were protected from infection whereas NRI route-immunized and unimmunized controls became infected. IgA ASC to p27 were increased significantly in the iliac lymph nodes of the TILN immunized macaques compared with unimmunized controls (P < 0.05). Only IgA ASC were found in the rectal mucosa of the immunized protected macaques but both IgA and IgG ASC were detected in the unimmunized infected macaques. Overall the number of IgG ASC specific for p27 was significantly higher in the infected NRI and control macaques than in the protected macaques (P < 0.02). A progressive increase in IgG but not IgA ASC was detected in the peripheral blood mononuclear cells of the unimmunized infected macaques. CONCLUSIONS: The results suggest that cells secreting IgA antibodies to p27 in the iliac lymph nodes of the TILN immunized macaques correlate significantly with protection from infection. The unimmunized infected macaques showed a progressive increase in IgG ASC in the peripheral blood after SIV challenge; this was found in the iliac and axillary lymph nodes and also in the spleen, suggesting that it is an immune response to the SIV infection.

Administration, Intranasal↗

PubMed2006

The osteogenic potential of adipose-derived stem cells for the repair of rabbit calvarial defects.

INTRODUCTION: Bone replacement is often necessary during reconstruction of craniofacial anomalies or trauma. Adipose-derived stem cells (ASCs) possess osteogenic potential and are a promising cell source for bone tissue engineering. The present study was designed to assess the osteogenic potential and utility of using ASCs to regenerate bone in a rabbit calvarial defect model. METHODS: Rabbit ASCs were seeded on gelatin foam (GF) scaffolds and induced in osteogenic medium containing bone morphogenetic protein (BMP)-2. Thirty-four 8-mm calvarial defects were randomly treated with autograft, no treatment, GF scaffold, GF + ASCs, or GF + osteoinduced ASCs. After 6 weeks, calvaria were harvested and underwent histologic and radiologic analyses to compare healing between the treatment groups. RESULTS: Defects treated with autograft underwent complete healing. Radiologically, there were no significant (P > 0.05) differences in healing among empty defects, and those treated with GF alone or GF plus osteoinduced ASCs. Osteoinduced ASCs exhibited significantly (P < 0.05) greater healing than noninduced ASCs. CONCLUSION: Preimplantation osteoinduction of ASCs enhances their osteogenic capacity. Lack of a significant osteogenic effect of ASCs on calvarial healing at 6 weeks may be secondary to use of noncritical-sized defects. Larger defects would likely demonstrate the osteogenic potential of ASCs more definitively.

Adipose Tissue↗

PubMed1996

Role of Apoplastic and Cell-Wall Peroxidases on the Stimulation of Root Elongation by Ascorbate.

Elongation of onion (Allium cepa L.) roots was highly stimulated by ascorbate (ASC) and its natural precursor I-galactone-[gamma]-lactone (GL). When incubation media were supplemented with lycorine (Lyc), an inhibitor of the ASC biosynthesis, root growth was negligible even in the presence of ASC or GL. ASC completely inhibited in vitro guaiacol peroxidase activities that were isolated from both the apoplast and the cell wall. However, ferulic-acid-dependent peroxidase from the cell wall was partially inhibited by ASC, whereas ferulic acid peroxidase activity from the apoplastic fluid was completely inhibited by ASC as long as ASC was present in the assay medium. ASC content in cells was increased by preincubations with ASC or GL, whereas Lyc reduced it. On the other hand, ASC or GL treatments decreased both apoplast and cell-wall-bound peroxidase activities, whereas Lyc had a slight stimulating effect. These results are discussed on the basis of a possible control of root elongation by ASC via its action on peroxidases that are involved in the regulation of cell-wall extensibility.

Journal Article↗

PubMed2006

Regulation of insulin secretion and beta-cell mass by activating signal cointegrator 2.

Activating signal cointegrator 2 (ASC-2) is a transcriptional coactivator of many nuclear receptors (NRs) and other transcription factors and contains two NR-interacting LXXLL motifs (NR boxes). In the pancreas, ASC-2 is expressed only in the endocrine cells of the islets of Langerhans, but not in the exocrine cells. Thus, we examined the potential role of ASC-2 in insulin secretion from pancreatic beta-cells. Overexpressed ASC-2 increased glucose-elicited insulin secretion, whereas insulin secretion was decreased in islets from ASC-2+/- mice. DN1 and DN2 are two dominant-negative fragments of ASC-2 that contain NR boxes 1 and 2, respectively, and block the interactions of cognate NRs with the endogenous ASC-2. Primary rat islets ectopically expressing DN1 or DN2 exhibited decreased insulin secretion. Furthermore, relative to the wild type, ASC-2+/- mice showed reduced islet mass and number, which correlated with increased apoptosis and decreased proliferation of ASC-2+/- islets. These results suggest that ASC-2 regulates insulin secretion and beta-cell survival and that the regulatory role of ASC-2 in insulin secretion appears to involve, at least in part, its interaction with NRs via its two NR boxes.

Amino Acid Motifs↗

PubMed1990

Comparison of arylsulfatase C and steroid sulfatase from human placenta and liver.

Human placental and hepatic arylsulfatase C (ASC) were purified to homogeneity and about 1,000-fold, respectively. Placental ASC hydrolyzed sterol sulfates at the same active site, whereas the major hepatic ASC did not. This major hepatic ASC isozyme was more thermolabile than placental ASC and steroid sulfatase from both placenta and liver. It was not precipitated by anti-bovine ASC IgG which quantitatively precipitated both placental ASC and steroid sulfatase activities from placenta and liver. A minor hepatic ASC isozyme with similar electrophoretic mobility to the placental enzyme copurified with the major hepatic ASC and is likely responsible for the steroid sulfatase activity in this organ. Hence, placental ASC and steroid sulfatase are biochemically and antigenically identical to hepatic steroid sulfatase. In contrast, the major hepatic ASC is a distinct protein whose catalytic and structural properties differ from all the above enzymes.

Arylsulfatases↗

PubMed2006

Prognostic value of apoptosis-associated speck-like protein containing a CARD gene promoter methylation in resectable non-small-cell lung cancer.

BACKGROUND: The apoptosis-associated speck-like protein containing a CARD (ASC) is a newly identified tumor suppressor gene that is frequently inactivated by de novo promoter methylation in non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: We studied 79 patients with NSCLC who had undergone surgery with curative intent. The ASC promoter methylation status was determined by methylation-specific polymerase chain reaction. Statistical analyses (all 2-sided) were performed to determine the prognostic effect of hypermethylation on various clinical parameters. RESULTS: ASC promoter hypermethylation was detectable by methylation-specific polymerase chain reaction in 9 of 70 (12.9%) normal lungs and in 33 of 70 (47.1%) matching tumor samples of patients with NSCLC. The mean ASC methylation level was significantly higher in tumor than in matching normal tissue (P < 0.001). ASC methylation in normal tissue was always accompanied with ASC methylation in matching tumor tissue. Patients without ASC promoter hypermethylation showed a significantly better survival than patients with ASC promoter hypermethylation (P = 0.007). Multivariate analysis revealed ASC promoter methylation as an independent unfavorable prognostic factor (P = 0.009). CONCLUSION: Our results indicate that ASC promoter hypermethylation is a common event in patients with primary NSCLC, and this epigenetic alteration is associated with inferior survival, suggesting that ASC promoter hypermethylation might be an important biomarker for a biologic, aggressive disease in NSCLC.

Adult↗

PubMed2003

Interaction and functional cooperation of the cancer-amplified transcriptional coactivator activating signal cointegrator-2 and E2F-1 in cell proliferation.

Activating signal cointegrator-2 (ASC-2), a novel coactivator, is amplified in several cancer cells and known to interact with mitogenic transcription factors, including serum response factor, activating protein-1, and nuclear factor-kappaB, suggesting the physiological role of ASC-2 in the promotion of cell proliferation. Here, we show that the expression pattern of ASC-2 was correlated with that of E2F-1 for protein increases at G(1) and S phase. Furthermore, cells stably overexpressing ASC-2 had an increased cell proliferation profile. These results prompted us to examine the functional interaction of ASC-2 and E2F-1. Biochemical evidence of protein interaction indicated that the transactivation domain of E2F-1 interacted with the COOH-terminal region of ASC-2. The importance of the E2F-1-ASC-2 interaction was supported by the demonstration that the coexpression of ASC-2 and E2F-1 synergistically transactivated E2F-1-driven gene transcription and the acetylation of E2F-1 protein was necessary for ASC-2-mediated transcriptional coactivation. Interestingly, overexpression of ASC-2 increased the endogenous protein level of E2F-1 in cells, resulting from the prolonged protein stability of E2F-1. Taken together, these results suggest that the cancer-amplified transcriptional coactivator ASC-2 may promote cell proliferation through enhancement of E2F-1-dependent transactivation of the expression of genes associated with cell cycle progression that may be available to favor tumor growth in vivo.

Acetylation↗

PubMed1994

Contribution of antibody-secreting cells induced in mucosal lymphoid tissues of pigs inoculated with respiratory or enteric strains of coronavirus to immunity against enteric coronavirus challenge.

Two antigenically related porcine coronaviruses, transmissible gastroenteritis virus (TGEV) which infects primarily the intestinal tract and causes severe diarrhea, and porcine respiratory coronavirus (PRCV) which infects the respiratory tract and causes subclinical or mild respiratory infections, presented a unique opportunity to study the interrelationship of gut-(GALT) and bronchus-associated lymphoid tissues (BALT) and their contribution to protective immunity against TGEV infection. Pigs were inoculated oral-nasally with TGEV or with PRCV at eleven days of age and challenged 24 days later with TGEV. All pigs initially given TGEV developed diarrhea and were completely protected against disease upon challenge. In contrast, pigs given PRCV had no clinical disease and shed virus in nasal secretions only; after challenge, 5 of 12 pigs developed diarrhea. Virus-specific IgG and IgA Ab-secreting cells (ASC) were enumerated by ELISPOT in the mesenteric and bronchial lymph nodes, spleens, and gut lamina propria at challenge and various post challenge days. Before challenge, in pigs exposed to TGEV, IgA-ASC in the duodenum and jejunum constituted the major ASC response. Conversely, PRCV-exposed pigs had mainly IgG-ASC in bronchial lymph nodes, with low ASC responses in the gut. After challenge, numbers of IgG-ASC increased rapidly in the gut lamina propria and mesenteric lymph nodes of only PRCV-primed pigs. Our results suggest that virus-specific IgG-ASC precursors derived in BALT of PRCV-primed pigs may migrate to the gut in response to TGEV challenge and contribute to the partial protection observed. The presence of IgA-ASC in the gut lamina propria of TGEV-primed pigs at the time of challenge correlated with complete protection against TGEV challenge. Thus a dichotomy exists in the BALT and GALT ASC responses; immunization via BALT induced a systemic type of response (IgG-ASC) and provided imperfect protection against an enteric pathogen, whereas immunization via GALT induced IgA-ASC and provided complete protection.

Animals↗

PubMed2005

Atypical squamous cells in exfoliative urinary cytology: clinicopathologic correlates.

Presence of atypical squamous cells (ASC) in voided urine is an uncommon finding that may be the harbinger of an underlying malignant process. ASCs in urine may precede a de novo histologic diagnosis of malignancy or be the first sign of a recurrence in the lower urinary tract, or the gynecologic tract (in women). This study analyzed all urine cytology specimens with such diagnoses, with reference to their final histologic outcome. All urine cytology cases (n = 17,446) that included ASCs, evaluated at The Johns Hopkins Hospital between 1989 and 2003 (14 yr), were reviewed for diagnoses. ASCs as defined in this study are keratinizing cells with large and hyperchromatic smudgy nuclei, high N/C ratio, abnormal nuclear or cytoplasmic shapes, and densely orangeophilic cytoplasm. These cases lacked the qualitative and quantitative criteria for malignancy. The final reference outcome was determined by subsequent histologic and clinical follow-up. Of these 17,446 urine specimens, 55 cases (0.3%) from 47 patients had ASCs present. Thirty-two of the 47 patients had adequate follow-up. In 8 of these 32 patients (25%), a diagnosis of squamous-cell carcinoma (SCC) of the urinary bladder or urothelial carcinoma (UC) with squamous differentiation was made on subsequent histologic examination. In two cases (6%) a diagnosis of high-grade cervical SCC was established on subsequent follow-up. Twenty two of 32 cases (69%) remained benign on histologic and prolonged clinical follow-up. We conclude that ASCs in urine are rare (0.3% in this series). An interpretation of ASCs in a urine specimen is made when there is insufficient qualitative/quantitative evidence for a carcinoma diagnosis. ASCs in urine are a clinically valid diagnostic category (31% were later diagnosed with SCC). Most patients with urinary ASCs do not develop malignancy and, therefore, these cells may represent a reactive/inflammatory process most commonly due to vaginal contamination (in women) or exfoliation from the distal urethra (in men). Rarely, ASCs may exfoliate from a uterine cervical SCC and, therefore, a pelvic examination should be considered in such patients.

Adult↗

PubMed1995

Human circulating specific antibody-forming cells after systemic and mucosal immunizations: differential homing commitments and cell surface differentiation markers.

Circulating spontaneous antibody-secreting cells (ASC) induced by mucosal and systemic immunizations in human volunteers have been characterized with respect to differentiation stage and homing commitments. Irrespective of the immunization route, the large majority of ASC co-expressed CD19 and HLA-DR, which are normally lost during the transition of plasmablasts to plasmocytes, as well as CD38, a marker of activated B cell blasts, expressed also by plasmocytes. However, these cells expressed neither CD28, a molecule acquired by plasmocytes, nor CD22 and CD37, which are lost during the transition of plasmablasts to plasmocytes. Therefore, the large majority of ASC found in peripheral blood after oral and parenteral immunizations are terminally differentiated B cells, but not fully differentiated plasmocytes. As a whole, the mucosally derived ASC population seemed to be more homogenously differentiated. CD25 was detected on few ASC, whereas ASC expressing CD71 were more numerous, especially among systemically derived ASC. Almost all ASC expressed the adhesion molecules CD44 and alpha 4-integrins, irrespective of immunization route. However, virtually all systemically derived ASC expressed L-selectin, recognizing the peripheral lymph node addressin, whereas only a minority of mucosally induced blood ASC expressed L-selectin. These studies are the first to demonstrate in humans that circulating precursors of mucosal B cell immunoblasts utilize organ-specific recognition mechanisms distinct from those of corresponding systemic B cells and appear to be more advanced in the B lineage maturation pathway. Specialization of receptor expression could explain both the unification of immune responses in diverse mucosal sites and the physiologic segregation of mucosal from non-mucosal immune mechanisms in humans.

Adult↗

PubMed2006

Multilineage differentiation of adipose-derived stromal cells from GFP transgenic mice.

Functional engineering of musculoskeletal tissues generally involves rapid expansion of progenitor cells in vitro while retaining their potential for further differentiation and then induction in specific culture conditions. The autologous adipose-derived stromal cells (ASCs) are considered to contain pluripotent mesenchymal stem cells. Imaging with expression of green fluorescent protein (GFP) facilitates the detailed research on ASCs physiological behavior during differentiation into a variety of cell lineages both in vitro and in vivo. In this study, we aimed to confirm the trans-germ plasticity of homogeneously marked ASCs from GFP transgenic mice. Simultaneously, the term and intensity of GFP expression in ASCs were also focused on during variant inductions, when cells were incubated with multiple growth factors and adjuvant. ASCs were harvested from inguinal fat pads of transgenic nude mice, passaged 3 times in monolayer cultures, and then transferred to osteogenic, adipogenic, neurogenic, and myogenic medium. The morphological characterization of inductive cells was observed using phase-contrast microscopy and histological staining such as alizarin red for mineralization nodules and oil red O for lipid accumulation. The expression of marker genes or proteins was measured using RT-PCR and immunocytochemical analysis. Collagen type I, osteopontin (OPN), and osteocalcin (OCN) were positive in osteogenic lineages, peroxisome proliferator-activated receptor(PPAR)-gamma2 and lipoprotein lipase (LPL) were positive in adipogenic ones, glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE) were positive in neurogenic ones, and alpha-smooth muscle actin (alpha-SMA) was positive in myogenic ones. Moreover, the results of fluorescence microscopic imaging suggested that there was no significant decline of GFP expression during ASCs differentiation and the level of GFP maintained stable till differentiated ASCs showed apoptotic phenotype. So the endogenous GFP and multilineage potential of transgenic ASCs had no influences on each other. Since the population of GFP ASCs can be easily identified, it is proposed that they may be promising candidate seed cells for further studies on ASCs tissue engineering, especially the study on engineered tissues formed in vivo.

Adipogenesis↗

PubMed1995

In vitro inhibition of human cytomegalovirus replication in human foreskin fibroblasts and endothelial cells by ascorbic acid 2-phosphate.

Antiviral activity of L-ascorbic acid-2-phosphate (ASC-2P), a long-acting derivative of L-ascorbic acid, against several human cytomegalovirus (CMV) strains was examined in cultures of human foreskin fibroblasts (HFF) and endothelial cells (EC). ASC-2P at concentrations ranging from 0.2 to 2 mM had no effect on the number of cells expressing 72 kDa CMV immediate early antigen (IEA) while it inhibited expression of 68 kDa late antigen (LA) in infected cultures of both cell types (30% and 55% reduction for EC and HFF, respectively). In HFF cells, virus yield was reduced up to 4-fold, when ASC-2P was added after CMV infection. Antiviral effects were significantly increased in cultures pretreated with ASC-2P. In HFF and EC pretreated for three subcultures (18 days) with 0.2 mM ASC-2P, a significant reduction of cells expressing IEA (75% and 80% reduction in EC and HFF, respectively) and LA (92% and 90% reduction for EC and HFF, respectively) was observed. Pretreatment for three subcultures with ASC-2P inhibited virus yield 50- to 100-fold in EC and 100- to 1000-fold in HFF. The continuous presence of ASC-2P was not required for its antiviral activity. A significantly higher reduction of virus replication with ganciclovir and foscarnet was obtained in ASC-2P pretreated cells than in untreated controls. The results showed that ASC-2P provides L-ascorbic acid with long-lasting antiviral activity against CMV. ASC-2P may be of benefit for the adjunctive treatment of CMV infection.

Antigens, Viral↗

PubMed1992

The effect of ascorbic acid on arachidonic acid and prostaglandin E2 metabolism in B16 murine melanoma cells.

Ascorbic acid (Asc), arachidonic acid (AA) and prostaglandin E2 (PGE2) are reported to be important in maintaining the stability of the cell matrix. Asc has also been shown to influence fatty acid (FA) and PGE2 synthesis, with the result that effects of Asc on cell growth are suggested to be mediated through the metabolism of these two compounds. This study examined the effect of Asc, supplemented over the concentration range of 0-100 micrograms/ml, on the in vitro cell growth of non-malignant LLCMK (monkey kidney) cells and malignant B16 murine melanoma cells. The effects of Asc supplementation on AA and PGE2 levels in the cell stroma and membrane fractions of the two cell types was also determined. Asc had no significant inhibitory or stimulatory effect on the growth of either the B16 or LLCMK cells. The total percentage AA composition determined in the B16 control cells (combined stroma and membrane fractions), was similar to that determined in the LLCMK control cells. Asc supplementation of the B16 cells, resulted in an inverse relationship between B16 cell growth and total percentage AA composition. PGE2 concentration in the control B16 cells (combined stroma and membrane fractions) was significantly higher than that detected in the control LLCMK cells. No PGE2 was detected in the B16 stroma fraction, with all appearing to be located in the membrane fraction. However, upon the supplementation of the B16 cells with increasing Asc concentrations, PGE2 appeared to be mobilized from the membrane fraction, resulting in increasing PGE2 levels in the stroma fraction relative to the membrane fraction. This was accompanied by a significant decrease in PGE2 concentration, in the membrane fraction. B16 cell growth and total (stroma and membrane fractions) PGE2 concentration in these cells was inversely related, when cultures were supplemented with increasing levels of Asc. Asc supplementation of the LLCMK cells did not appear to have any significant effect on AA or PGE2 metabolism in these cells.

Animals↗