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1.
Plant Dis ; 98(7): 990, 2014 Jul.
Article in English | MEDLINE | ID: mdl-30708930

ABSTRACT

Sunn hemp (Crotalaria juncea L., Fabaceae) is widely used as a cover crop in sugar cane and citrus plantations in Brazil. C. juncea has been reported in São Paulo State (SPS) by Wulff et al. (3) as a host of the phytoplasma associated with symptoms of huanglongbing (HLB) in citrus, a member of group 16SrIX, that induces witches'-broom in sunn hemp (3). In studying the distribution of group 16SrIX phytoplasma in C. juncea in SPS, we identified this species as a new host of two phytoplasmas. Sunn hemp fields were inspected for symptoms usually associated with phytoplasma infections, such as leaf yellowing, shoot proliferation, witches'-brooms, and virescence. Ninety-nine plant samples were collected and DNA was extracted with the CTAB protocol from stems. Nested PCR was carried out with primers P1/P7, followed by amplification with primers fU3/rU5 (2), both sets being universal for phytoplasma. Asymptomatic sunn hemp samples were used as negative controls and were negative in PCR reactions. PCR products were directly sequenced with primers P1/P7 and fU3/rU5 and phytoplasma identification was conducted with BLASTn and in silico RFLP analysis for delineation of subgroups (4). Plants showing leaf yellowing (three plants; Catanduva County), shoot proliferation (one plant; Ibirá County), or witches'-brooms (one plant; Promissão County) symptoms were found to be infected with the 16SrI phytoplasma group, subgroup S. The 16S rDNA sequence (GenBank Accession No. KF878383) showed 99% identity (E value 0.0) with Candidatus Phytoplasma asteris, Onion yellows phytoplasma OY-M (AP006628), Mulberry yellow dwarf phytoplasma (GQ249410), and Ash witches'-broom phytoplasma (AY566302), among other phytoplasmas from the same group. Sunn hemp plants with shoot proliferation (three plants) carried the 16SrXV phytoplasma group, subgroup A, found in Ibirá (two plants) and Catanduva (one plant) counties, SPS. This sequence (GenBank Accession No. KF878382) displayed 99% identity (E value 0.0) with Ca. P. brasiliense, Hibiscus witches'-broom phytoplasma (AF147708), Guazuma ulmifolia witches'-broom phytoplasma (HQ258882, HQ258883), and Cauliflower stunt phytoplasma (JN818845). Both phytoplasma groups described in this report, 16SrI and 16SrXV, were collected in May 2010 and both have limited geographic distribution and occurred at low incidence. Phytoplasma of group 16SrI (Ca. P. asteris) was identified in C. spectabilis in India (1). To our knowledge, this is the first report of phytoplasmas groups 16SrI and 16SrXV in sunn hemp. References: (1) S. Kumar et al. Plant Dis. 94:1265, 2010. (2) E. Seemüller et al. Int. J. Syst. Bacteriol. 44:440, 1994. (3) N. A. Wulff et al. Tropical Plant Pathol. 34:S7, 2009. (4) Y. Zhao et al. Int. J. Syst. Evol. Microbiol. 59:2582, 2009.

2.
J Exp Med ; 164(4): 1171-8, 1986 Oct 01.
Article in English | MEDLINE | ID: mdl-3760777

ABSTRACT

Old Fischer 344 rats are more susceptible to vascular lesions after arterial endothelial injury than are young animals. Thus, 20-26-mo-old Fischer 344 rats developed greater and more persistent intimal proliferative lesions than did 2-5-mo-old rats after aortic endothelial denudation. 3 d after deendothelialization, intimal thickness was increased two-fold in both old and young animals. However, 14 d after endothelial injury, intimal thickness had increased nearly five times in old animals, but had regressed to normal in young animals. Intimal thickness of young aortic grafts transplanted into young recipients did not differ significantly from adjacent host aorta or autotransplanted aortic segments 6 wk after surgery. In contrast, intimal thickness of old grafts transplanted into young recipients was eight times greater than adjacent young host aorta 6 wk after surgery. The density of cell nuclei in the intima of old grafts was also much greater than that in young grafts. Thus, in two experimental models of vascular injury, old rats have consistently had greater myointimal hyperplasia than young rats. The increased proliferative response of aortic smooth muscle cells after vascular injury of old animals may contribute to the increased prevalence of vascular disease with age.


Subject(s)
Aging , Arteriosclerosis/etiology , Blood Vessels/pathology , Animals , Aorta/transplantation , Arteriosclerosis/pathology , Endothelium/physiology , Hyperplasia , Male , Monocytes/pathology , Muscle, Smooth, Vascular/pathology , Rats , Rats, Inbred F344
3.
Oral Dis ; 15(2): 133-41, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19207484

ABSTRACT

Necrotizing fasciitis of the cervical facial region is a rare entity that has seen an increasing prevalence in the last 20 years. It is most common in patients with an underlying systemic disease leading to immunosuppression, but can be seen in healthy adults and children. It is characterized by soft tissue destruction which is disproportionate to its clinical symptoms and signs, with rapid progression and fatal outcome, if not treated rapidly and radically. We present a review of the etio-pathogenesis and management of this challenging disease.


Subject(s)
Face , Fasciitis, Necrotizing/pathology , Mouth Diseases/pathology , Neck , Soft Tissue Infections/pathology , Adolescent , Anti-Bacterial Agents/therapeutic use , Child , Child, Preschool , Debridement , Fasciitis, Necrotizing/etiology , Fasciitis, Necrotizing/mortality , Fasciitis, Necrotizing/therapy , Humans , Mouth Diseases/complications , Soft Tissue Infections/etiology , Soft Tissue Infections/therapy , Young Adult
4.
Eur Rev Med Pharmacol Sci ; 23(17): 7183, 2019 09.
Article in English | MEDLINE | ID: mdl-31539103

ABSTRACT

The article "Angiotensin II induces the exocytosis of galectin-3 via integrin αv/AKT/NF-κB signaling pathway" by L. Tian, D. Coletti, Z.-L. Li, published in Eur Rev Med Pharmacol Sci 2019; 23(13): 5949-5957 has been retracted with the unanimous agreements of all the authors and the Editors-in-Chief, since the corresponding author submitted the manuscript for review without informing and obtaining the agreement of the senior co-authors.

5.
Eur Rev Med Pharmacol Sci ; 23(13): 5949-5957, 2019 07.
Article in English | MEDLINE | ID: mdl-31298346

ABSTRACT

OBJECTIVE: To explore the role of integrin αv in Angiotensin II (Ang II)-induced exocytosis and endocytosis of galectin-3 (gal-3) in vascular smooth muscle cells (VSMCs). MATERIALS AND METHODS: A primary culture of mouse VSMCs was established by the enzymatic digestion of aorta. Adeno-Cre was used to specifically knockdown integrin αv. VSMCs were treated with Ang II, LY294002 (inhibitor of AKT signaling pathway), and Bay11-7082 (inhibitor of nuclear factor-kappa B, NF-κB), respectively. Endocytosis of His-tagged gal-3 was analyzed by immunofluorescence. The Western blot was performed to detect the protein level in cell supernatant and lysate. RESULTS: Ang II increased the exocytosis of gal-3 and activated AKT and NF-κB signaling pathways. The knockdown integrin αv effectively decreased the activation of AKT and NF-κB signals and the exocytosis of gal-3 induced by Ang II, but it had a little effect on the endocytosis of gal-3. Ang II increased the phosphorylation of AKT and NF-κB through integrin αv. AKT is the upstream signal of the NF-κB signaling pathway. LY294002 or Bay11-7082 could decrease Ang II-induced exocytosis of gal-3 in VSMCs. CONCLUSIONS: Ang II, depending on integrin αv/AKT/NF-κB signaling pathway, induced the exocytosis of gal-3.

6.
Int J Oral Maxillofac Surg ; 37(3): 215-22, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18023145

ABSTRACT

This paper reports on the largest series of pathological fractures of the mandible (n=44) in the literature, with the aim of proposing an aetiologic classification and algorithm for treatment. A retrospective review was undertaken of cases treated in the Department of Oral and Maxillofacial Surgery at the University of Maryland Medical Center from 1991 to 2005. Data collected included age, gender, race, aetiology, site, management and outcome. Forty-three patients with 44 pathologic fractures were included. The most common aetiology was osteoradionecrosis (49%), followed by infections (19%) and malignancy (19%). The most frequent primary treatment utilized was mandibular resection of diseased bone and fixation with a locking reconstruction plate alone (55%). Either primary or secondary mandibular reconstruction was performed when co-morbid disease allowed such treatment. Management of pathological fractures is aimed initially at systemic issues, followed by focusing on site-specific issues. This is a complex problem with a 40% complication rate, with radiation therapy associated with 59% of the complications. Free flap reconstruction should be considered when possible, especially in cases secondary to osteoradionecrosis.


Subject(s)
Fractures, Spontaneous/surgery , Mandibular Fractures/surgery , Adult , Aged , Aged, 80 and over , Algorithms , Bone Plates , Child, Preschool , Disease , Female , Follow-Up Studies , Fractures, Spontaneous/etiology , Humans , Male , Mandible/surgery , Mandibular Diseases/complications , Mandibular Diseases/surgery , Mandibular Fractures/etiology , Mandibular Neoplasms/complications , Mandibular Neoplasms/surgery , Middle Aged , Osteomyelitis/complications , Osteomyelitis/surgery , Osteoradionecrosis/complications , Osteoradionecrosis/surgery , Postoperative Complications , Plastic Surgery Procedures/instrumentation , Retrospective Studies , Treatment Outcome
7.
Eur J Histochem ; 51 Suppl 1: 35-43, 2007.
Article in English | MEDLINE | ID: mdl-17703592

ABSTRACT

One of the most exciting aspirations of current medical science is the regeneration of damaged body parts. The capacity of adult tissues to regenerate in response to injury stimuli represents an important homeostatic process that until recently was thought to be limited in mammals to tissues with high turnover such as blood and skin. However, it is now generally accepted that each tissue type, even those considered post-mitotic, such as nerve or muscle, contains a reserve of undifferentiated progenitor cells, loosely termed stem cells, participating in tissue regeneration and repair. Skeletal muscle regeneration is a coordinate process in which several factors are sequentially activated to maintain and preserve muscle structure and function upon injury stimuli. In this review, we will discuss the role of stem cells in muscle regeneration and repair and the critical role of specific factors, such as IGF-1, vasopressin and TNF-alpha, in the modulation of the myogenic program and in the regulation of muscle regeneration and homeostasis.


Subject(s)
Aging/physiology , Muscle, Skeletal/physiology , Neuromuscular Diseases/physiopathology , Regeneration , Animals , Cell Differentiation , Humans , Insulin-Like Growth Factor I/metabolism , Stem Cells/physiology , Tumor Necrosis Factor-alpha/metabolism , Vasopressins/metabolism
8.
G Ital Med Lav Ergon ; 27(2): 244-9, 2005.
Article in Italian | MEDLINE | ID: mdl-16124539

ABSTRACT

Polychlorinated biphenyls (PCBs) are structurally related to dioxins, widely used in the past in various industrial applications and daily used products. Although PCBs production was discontinued more than twenty years ago, their chemical stability and high lipophilicity make them persistent pollutants and dangerous occupational contaminants. Skeletal muscle is an important site of PCB accumulation. Our previous results about the effects of PCBs on L6C5 myoblasts, showed that "low concentrations" (< 10 microg/ml) of these compounds inhibit in vitro myogenic differentiation in a concentration-dependent fashion, while toxic effects only begin to be evident at PCB concentrations > or = 10 microg/ml. In the present paper we wondered if the observed cell mortality is due to necrosis or if it depends on the activation of programmed cell death mechanisms (apoptosis). Using different methods of analysis, we have observed that PCBs cause necrosis of myogenic cells and that such effect is related to the employed concentrations and to the time of exposure (EC50 approximately = 50 microg/ml). Our results may help to explain the creatin kinase elevation, observed in the blood of patients acutely exposed to high concentrations of PCBs, as the consequence of a necrotic damage of the skeletal muscle. It will be therefore interesting to evaluate the presence of muscular damages in the chronic exposures to PCBs.


Subject(s)
Environmental Pollutants/toxicity , Myoblasts/drug effects , Polychlorinated Biphenyls/toxicity , Animals , Apoptosis , Cell Line , Creatine Kinase/blood , Cytophotometry , Cytoplasm/enzymology , Data Interpretation, Statistical , Environmental Pollutants/administration & dosage , Humans , L-Lactate Dehydrogenase/analysis , Myoblasts/pathology , Necrosis/chemically induced , Necrosis/enzymology , Polychlorinated Biphenyls/administration & dosage , Rats
9.
Leuk Res ; 21(5): 375-80, 1997 May.
Article in English | MEDLINE | ID: mdl-9225062

ABSTRACT

Thirteen patients with accelerated phase of chronic myeloid leukemia (CML-AC) were treated with intravenous plicamycin and subcutaneous alpha-interferon. Two patients stabilized, three patients had partial hematologic responses and one patient had a hematologic complete response with a major cytogenetic response. Two patients, progressing on hydroxyurea, did not respond, but demonstrated re-sensitization to hydroxyurea after completion of induction therapy and had prolonged return to chronic phase for 30 months and 25 months. Four non-responders subsequently received additional chemotherapy and responded. Median survival of all study patients from the development of accelerated phase of CML was 24 months: substantially longer than other reported series (median 6 months). Plicamycin appears to add efficacy to interferon in the stabilization of accelerated phase of CML.


Subject(s)
Antibiotics, Antineoplastic/therapeutic use , Antineoplastic Agents/therapeutic use , Interferon-alpha/therapeutic use , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy , Plicamycin/therapeutic use , Adult , Aged , Antibiotics, Antineoplastic/administration & dosage , Antineoplastic Agents/administration & dosage , Biopsy , Bone Marrow/pathology , Drug Administration Schedule , Female , Humans , Hydroxyurea/therapeutic use , Infusions, Intravenous , Injections, Subcutaneous , Interferon-alpha/administration & dosage , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/mortality , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Pilot Projects , Plicamycin/administration & dosage , Survival Rate
10.
J Am Acad Child Adolesc Psychiatry ; 40(12): 1448-56, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11765291

ABSTRACT

BACKGROUND: A combination of an antipsychotic medication and a mood stabilizer is often used for initial treatment of acute psychotic mania. However, the optimal duration of this adjunctive antipsychotic medication is unknown. METHOD: As part of a lithium efficacy study, acutely manic adolescents with psychotic features were given open combination treatment with lithium and an adjunctive antipsychotic medication. If the psychosis resolved, the antipsychotic medication dose was gradually tapered and discontinued after 4 weeks of therapeutic lithium levels. The subject was then given a trial of maintenance lithium monotherapy for up to 4 weeks. RESULTS: Significant improvement was seen in 64% of the sample with psychotic features after 4 weeks of combination treatment. However, few maintained their response after discontinuation of the antipsychotic medication. Successful discontinuation of antipsychotic medication in this sample was associated with first episode, shorter duration of psychosis, and the presence of thought disorder at baseline. CONCLUSIONS: Adjunctive antipsychotic medication needs to be maintained for longer than 4 weeks in the vast majority of adolescents with psychotic mania, even though the manic and psychotic symptoms have resolved and lithium treatment is maintained. Future studies to determine the optimal duration of adjunctive antipsychotic medication treatment are warranted.


Subject(s)
Antipsychotic Agents/therapeutic use , Bipolar Disorder/drug therapy , Lithium/therapeutic use , Lorazepam/therapeutic use , Adolescent , Bipolar Disorder/diagnosis , Child , Drug Therapy, Combination , Female , Humans , Male , Psychiatric Status Rating Scales , Risperidone/therapeutic use , Severity of Illness Index
11.
J Affect Disord ; 51(2): 153-64, 1998 Nov.
Article in English | MEDLINE | ID: mdl-10743848

ABSTRACT

OBJECTIVE: To examine if childhood psychiatric diagnoses are associated with family history, psychosis, age, and lithium response. METHOD: Associations among variables, and their contributions to explaining lithium response were examined in 48 bipolar adolescents enrolled in a study of lithium. RESULTS: Presence of a childhood diagnosis was not associated with family psychiatric history or lithium response. Subjects with psychotic features, however, were less likely to have a childhood psychiatric diagnosis, were older, and had a poorer response rate to lithium than subjects without psychosis. DISCUSSION: Heterogeneity within bipolar adolescents may be based on clinical features such as psychosis rather than childhood or family history alone.


Subject(s)
Antimanic Agents/therapeutic use , Bipolar Disorder/drug therapy , Lithium Carbonate/therapeutic use , Psychotic Disorders/drug therapy , Adolescent , Antimanic Agents/adverse effects , Bipolar Disorder/diagnosis , Bipolar Disorder/genetics , Child , Comorbidity , Double-Blind Method , Female , Genetic Predisposition to Disease/genetics , Humans , Lithium Carbonate/adverse effects , Male , Prognosis , Psychiatric Status Rating Scales , Psychotic Disorders/diagnosis , Psychotic Disorders/genetics , Risk Factors , Treatment Outcome
12.
J Child Adolesc Psychopharmacol ; 11(4): 409-13, 2001.
Article in English | MEDLINE | ID: mdl-11838823

ABSTRACT

Adolescents with acute psychotic mania were treated with lithium and adjunctive haloperidol as part of a lithium efficacy study. If the psychosis completely resolved, haloperidol was discontinued after 1 week of therapeutic lithium levels. Our first five subjects experienced a rapid exacerbation of symptoms, which responded to restarting haloperidol. A longer duration of adjunctive antipsychotic treatment is necessary in adolescents with bipolar psychosis.


Subject(s)
Bipolar Disorder/complications , Bipolar Disorder/drug therapy , Drug Therapy, Combination , Haloperidol/therapeutic use , Lithium/therapeutic use , Psychotic Disorders/complications , Psychotic Disorders/drug therapy , Acute Disease , Adolescent , Age Factors , Child , Double-Blind Method , Female , Haloperidol/administration & dosage , Humans , Lithium/administration & dosage , Male , Psychological Tests , Severity of Illness Index , Time Factors
13.
In Vitro Cell Dev Biol Anim ; 36(3): 153-62, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10777054

ABSTRACT

In order to isolate, characterize, and establish culture cell lines with different diagnostic and prognostic significance, derived from multiclonal neoplasms, a ductal infiltrating mammary tumor was induced in rats by 7,12-dimethylbenz[a]anthracene. Clones with different DNA/protein content, being the DI of 1.16, 1.30, and 1.60, respectively, were observed in the primary tumor. Biparametric flow cytometry suggested that the clone at 1.30 is made up of two subpopulations with different protein and slightly different DNA contents. The culture, after a few passages, exhibited the presence of aneuploid cells and the absence of diploid components, demonstrating that only tumor cells survived. The limiting dilution method gave rise to four lines with DI of 1.16, 1.25, 1.30, and 1.50; a mean chromosome number of 45, 46, 47, and 88, respectively; and different morphological and ultrastructural features. These characteristics were stable during the experimental procedure, that is, for about 20 passages. Conversely, the detection of cytoskeletal proteins indicated that the tumor epithelial cells underwent early dedifferentiation into sarcoma-like cells showing markers of stromal cell type and thus exhibiting phenotypic instability in vitro, a feature reported in many advanced human breast cancers in vivo. In conclusion, this cellular model represents the in vivo situation and appears suitable for in vitro studies of tumor cell characteristics and might be used to predict clinical behavior.


Subject(s)
Cell Culture Techniques , Mammary Neoplasms, Experimental , Tumor Cells, Cultured , Animals , Cell Culture Techniques/methods , Cytoskeleton/metabolism , DNA, Neoplasm/analysis , Female , Flow Cytometry/methods , Immunohistochemistry/methods , Mammary Neoplasms, Experimental/chemically induced , Microscopy, Electron/methods , Neoplasm Proteins/analysis , Rats , Rats, Sprague-Dawley
14.
Dent Mater ; 16(1): 62-7, 2000 Jan.
Article in English | MEDLINE | ID: mdl-11203525

ABSTRACT

OBJECTIVES: In vivo wear of composite restorative materials appears to be, in part, dependent on various patient factors. Specifically, consumption of alcoholic beverages has the potential for increasing the degradation rate. The hypothesis tested in this experiment was that composite wear is dependent on the type of alcohol-containing liquid the materials are exposed to during three-body abrasive wear. METHODS: To test this hypothesis, composite wear experiments were performed using the ACTA three-body wear machine. Abrasive slurries containing either beer, wine, 9 vol% ethanol or water were used during the wear experiments. The data were analyzed using ANOVA and Tukey's test. RESULTS: The wine and ethanol solutions caused significantly more wear compared to the beer and water. There was no significant differences in the wear between the wine and 9 vol% ethanol groups, and the beer groups were not significantly different from the water groups. Furthermore, there was no significant interaction between the composite type and the various abrasive slurries. SIGNIFICANCE: These results indicate that alcoholic beverages with at least 9 vol% ethanol will increase the wear of composite. The observed increase in wear of composite by the wine was caused primarily by the ethanol content of the wine. Other constituents in the wine do not appear to have an effect on composite wear. The ethanol effect was consistent among different composite types.


Subject(s)
Alcoholic Beverages , Composite Resins/chemistry , Dental Restoration Wear , Analysis of Variance , Beer , Bisphenol A-Glycidyl Methacrylate/chemistry , Ethanol/chemistry , Materials Testing , Resin Cements/chemistry , Silicon Dioxide/chemistry , Statistics, Nonparametric , Wine , Zirconium/chemistry
16.
Int J Oral Maxillofac Surg ; 38(9): 960-3, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19423294

ABSTRACT

Mandibular reconstruction plates have revolutionized the treatment of mandibular continuity defects following ablative or trauma surgery. This retrospective study of patients requiring mandibular reconstruction over a six year period describes the authors' experience with second generation mandibular locking reconstruction plates and identifies complications and risk factors. The use of second-generation locking reconstruction plates for the treatment of mandibular continuity defects has a 36% complication rate, which includes plate fracture, screw loosening, plate exposure, wound infection and malocclusion. The average time frame until a hardware failure (plate fracture, screw loosening) occurs is 14 months. Plate exposure is closely associated with patients who received radiation therapy, and have lateral defects reconstructed with a plate only or plate/soft tissue flap reconstruction. Plate fracture was associated with lateral defects, the presence of a postoperative dentition, and a plate only or plate/soft tissue flap reconstruction. The authors recommend the use of a primary vascularized bone reconstruction. This provides additional soft tissue support around the plate to minimize the chances of exposure. It also provides osseous support for the plate, reducing the time frame the plate endures load bearing, and minimizing the risk of plate fracture.


Subject(s)
Bone Plates , Mandibular Prosthesis Implantation/instrumentation , Mandibular Prosthesis , Orthognathic Surgical Procedures/instrumentation , Plastic Surgery Procedures/instrumentation , Chi-Square Distribution , Cohort Studies , Female , Humans , Male , Mandibular Diseases/rehabilitation , Mandibular Diseases/surgery , Mandibular Neoplasms/rehabilitation , Mandibular Neoplasms/surgery , Mandibular Prosthesis Implantation/methods , Orthognathic Surgical Procedures/methods , Prosthesis Design , Prosthesis Failure , Plastic Surgery Procedures/methods , Retrospective Studies , Statistics, Nonparametric , Treatment Outcome
17.
J Cell Physiol ; 202(3): 787-95, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15389566

ABSTRACT

Calcium plays a pivotal role in the establishment of the differentiated phenotype in myogenic cells but the involved molecular mechanisms are still matter of debate. Here we studied the effects of exposing L6-C5 myogenic cells to high extracellular Ca2+ concentration ([Ca2+]o), which induces an increase of intracellular calcium ([Ca2+]i) without involving Ca2+ release from the intracellular stores but exclusively due to plasma membrane influx (Naro et al., 2003). Exposure of L6-C5 cells to [Ca2+]o up to 20 mM for 30 min, before shifting them into a differentiative medium, induced the appearance of multinucleated, myosin-positive myotubes, much larger than in control cells with an increased protein/DNA ratio. These large myotubes showed nuclear accumulation of the hypertrophy marker GATA-2. The hypertrophic growth of these cells was blocked by cyclosporin A (CsA), FK506, or overexpression of a calcineurin-dominant negative protein, suggesting the involvement in this process of the Ca2+ responsive phosphatase calcineurin. Furthermore, transient exposure of L6-C5 cells to high [Ca2+]o increased the expression of luciferase reporter driven by myoglobin (Mb) and beta-MHC promoters but not IIB-MHC and MCK promoters. Luciferase transcription driven by CK promoter was, instead, enhanced by mobilizing Ca2+ from the intracellular stores. These data indicate that a transient increase of [Ca2+]i due to plasma-membrane influx is sufficient to induce a hypertrophic phenotype and an increased expression of slow-fiber genes but not fast-fiber genes.


Subject(s)
Calcium/metabolism , Gene Expression Regulation , Muscle Fibers, Skeletal/cytology , Transcription, Genetic , Animals , Calcineurin/metabolism , Cell Differentiation/physiology , Cell Line , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , GATA2 Transcription Factor , Hypertrophy , Muscle Development , Muscle Fibers, Skeletal/metabolism , Muscle Fibers, Slow-Twitch/physiology , Myosins/genetics , Myosins/metabolism , Promoter Regions, Genetic , Rats , Signal Transduction/physiology , Transcription Factors/genetics , Transcription Factors/metabolism
18.
Exp Cell Res ; 256(1): 94-104, 2000 Apr 10.
Article in English | MEDLINE | ID: mdl-10739656

ABSTRACT

Phospholipase D (PLD) activation involved in signal transduction may lead to the hydrolysis of conspicuous amounts of phosphatidylcholine (PC). This study shows that PLD activation significantly alters the plasma membrane (PM) environment and the membrane exchange dynamics. PC-PLD activation in vasopressin (AVP)-stimulated L6 myogenic cells was accompanied by increased exocytosis and decreased membrane fluidity, as shown by transmission EM and fluorescence spectroscopy of trimethylammonium-diphenyl-hexatriene. AVP-induced exocytosis appeared to be brefeldin A-insensitive. PLD inhibition by Zn(2+) and PC de novo synthesis inhibition by hexadecylphosphocholine abolished AVP-induced vesicle traffic. Upon AVP stimulation, metabolically labeled PC decreased in PM, then transiently increased in microsomes, and returned to the prestimulus level in the PM within 5 min, a phenomenon requiring PC neosynthesis and microtubule functionality. Vesicle traffic with similar features was also observed after endothelin-1-induced PC-PLD activation in rat peritubular myoid cells. These results indicate that, in nonsecretory cells, exocytosis coupled to PC de novo synthesis restores PM-PC, conspicuously consumed during PLD-mediated signal transduction.


Subject(s)
Arginine Vasopressin/pharmacology , Cell Membrane/physiology , Phosphatidylcholines/metabolism , Phospholipase D/metabolism , Acrylamide/pharmacology , Androstadienes/pharmacology , Animals , Brefeldin A/pharmacology , Cell Line , Cell Membrane/drug effects , Cell Membrane/ultrastructure , Cytochalasin B/pharmacology , Diphenylhexatriene/analogs & derivatives , Enzyme Activation , Exocytosis , Fluorescent Dyes , Kinetics , Membrane Lipids/metabolism , Muscle, Skeletal , Nocodazole/pharmacology , Paclitaxel/pharmacology , Rats , Wortmannin , Zinc/pharmacology
19.
Arch Histol Cytol ; 63(5): 441-9, 2000.
Article in English | MEDLINE | ID: mdl-11201202

ABSTRACT

The plasma membrane is dynamically remodeled as a function of the cell cycle, motility and membrane traffic. We have previously shown that arg8-vasopressin (AVP) stimulation of L6 myoblasts induces the activation of phosholipase D during the first minutes of stimulation, and the differentiation of 1,6 myoblasts as a long term effect. We now report that AVP also induces two types of morphological responses in L6 cells within a few minutes of stimulation: exocytosis, apparent as uncoated pits, and the generation of membrane projections and reffles. Thus, such an experimental model is suitable for the study of hormone-induced morphological surface modifications and their regulatory mechanisms. In L6 cells, AVP-induced projection generation depends on the integrity of microfilaments, intermediate filaments, and microtubules. Moreover, projection generation and exocytosis appear to be independently regulated phenomena: in fact, inhibition of the de novo synthesis of phosphatidylcholine inhibits membrane traffic but fails to block projection appearance. Conversely, the latter phenomenon, unlike exocytosis, is mediated by PI3-kinase signaling. Thus, AVP induces two early, independently regulated morphological modifications in L6 cells: exocytosis, involved in plasma membrane phospholipid turnover, and membrane projections, likely involved in cell migration.


Subject(s)
Cell Membrane/drug effects , Phosphorylcholine/analogs & derivatives , Vasopressins/pharmacology , Acridine Orange/pharmacology , Acrylamide/pharmacology , Androstadienes/pharmacology , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Cell Line , Cell Membrane/ultrastructure , Cell Movement , Cytochalasin B/pharmacology , Enzyme Inhibitors/pharmacology , Exocytosis/drug effects , Fluorescent Dyes/pharmacology , Fluorometry , Kinetics , Ligands , Microscopy, Electron , Microscopy, Electron, Scanning , Muscles/cytology , Muscles/ultrastructure , Paclitaxel/pharmacology , Phosphatidylcholines/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phospholipids/metabolism , Phosphorylcholine/pharmacology , Rats , Signal Transduction , Time Factors , Wortmannin
20.
Cell Mol Biol (Noisy-le-grand) ; 42(8): 1229-42, 1996 Dec.
Article in English | MEDLINE | ID: mdl-8997526

ABSTRACT

We have analyzed the pattern of time-dependent and concentration-dependent incorporation of Lucifer Yellow CH (LY) and Horseradish Peroxidase (HRP) by human umbilical vein endothelial cells cultured on a non-adhesive substratum, where they they become organized into stable, multicellular aggregates. The data were compared with those previously obtained from low-density cultures of non-growing endothelial cells adherent to plastic. While the linear trend of the incorporation kinetics is preserved, the rate of uptake with both time and concentrations is highly dependent on the culture conditions, namely typology of cell-cell and cell-substrate interactions. An at least two-fold increase of the rate of uptake was observed with both markers in the aggregated cells. The extracellular concentration of LY required to saturate the binding capacity of the cell surface shifts from approximately 0.25 mg/ml, with the adherent cells, to approximately 0.5 mg/ml in the aggregated cells; the rate of uptake of three different forms of HRP shows, besides a sharp quantitative increase, also qualitative variations, testified by differential changes of their incorporation rates. These results are entirely consistent with the assumption that the association of the endothelial cells into multicellular aggregates increases the rate of pinocytic uptake by modifying the physicochemical properties of the cell surface, thereby increasing its differential affinity for the extracellular markers.


Subject(s)
Endothelium, Vascular/physiology , Horseradish Peroxidase/metabolism , Isoquinolines/metabolism , Pinocytosis/physiology , Biological Transport , Cell Adhesion/physiology , Cell Aggregation , Cells, Cultured , Endothelium, Vascular/ultrastructure , Humans , Intercellular Junctions , Umbilical Veins/cytology
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