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1.
Zhonghua Yi Xue Za Zhi ; 96(32): 2569-72, 2016 Aug 23.
Artículo en Zh | MEDLINE | ID: mdl-27596553

RESUMEN

OBJECTIVE: To investigate the difference in severity and clinical outcomes between hypertriglyceridemic pancreatitis (HTGP) and acute pancreatitis (AP) of other causes, and to analyze the correlation between the serum triglyceride (TG) level <24 h after onset and the disease severity. METHODS: Patients were selected from the AP database of the First Affiliated Hospital of Nanchang University, who were admitted between January 2005 and December 2013, aged ≥18 and ≤85 years, excluding pregnant or lactating women. Severity and etiology of AP were classified according to the latest relevant guidelines. The severity and clinical outcomes of HTGP patients (HTGP group) were compared with those of patients with AP of other causes (non-HTGP group). Among the HTGP patients, those admitted within 24 hours of onset were selected for comparison of serum TG levels on the first day of hospitalization day among patients with mild, moderate, and severe HTGP, and the correlation between the serum TG level and the severity was analyzed. RESULTS: Altogether 3 558 AP patients were selected, of which 623 (17.5%) were HTGP, and 2 935 (82.5%)were non-HTGP patients. Compared with the non-HTGP group, the HTGP group had higher incidence of pancreatic necrosis (28.3% vs 18.1%), infected pancreatic necrosis (6.1% vs 3.7%), organ failure(35.8% vs 29.1%), and persistent organ failure(24.4% vs 16.5%), with all the differences being statistically significant (all P<0.01). The mortality and average stay in intensive care unit were also higher in the HTGP group than in the non-HTGP group (all P<0.05). There were 291 patients with HTGP who were admitted to hospital within 24 hours of onset. The serum TG levels <24 h after onset were (9.38±9.00) mmol/L, (11.90±9.02) mmol/L, and (16.47±11.75) mmol/L in patients with mild, moderate, and severe HTGP, respectively (P<0.01). Spearman's correlation analysis showed a positive correlation between TG level <24 h after onset and disease severity (r=0.26, P<0.01). CONCLUSIONS: Compared with AP of other causes, HTGP patients have more severe clinical course and worse clinical outcomes. The serum TG level within 24 hours of onset may be positively correlated with the severity of HTGP.


Asunto(s)
Lactancia , Pancreatitis , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Hiperglucemia , Incidencia , Persona de Mediana Edad , Embarazo , Índice de Severidad de la Enfermedad , Resultado del Tratamiento , Adulto Joven
2.
Poult Sci ; 91(11): 2852-7, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23091142

RESUMEN

Bacillus subtilis ANSB060 from the fish gut had strong ability to detoxify aflatoxins. The aim of this research was to investigate the protective effect of B. subtilis ANSB060 (ANSB060) on egg quality and biochemical and histopathological changes of liver and kidney in laying hens when exposed to aflatoxin B(1). Treatments (C20, C40, and C60) were prepared by substituting corn contaminated by aflatoxin B(1) (AFB1) at different proportions (20, 40, and 60%) for normal corn in basic diets. The aflatoxin degradation enzyme (E) treatments (E20, E40, and E60) were mixed with the fermentation liquor of ANSB060 with C20, C40, and C60, respectively. The results showed that ANSB060 can improve the eggshell strength in E60 compared with C60 (P ≤ 0.05), and toxin reduced the content of total protein (in groups C20, C40, and C60) and albumin (in C20 and C40; P < 0.05) and heightened the activities of GPT (in C60) and GOT (in C40 and C60) in serum (P < 0.05). In the liver, AFB1 inhibited the activity of superoxide dismutase and glutathione peroxidase (C40 and C60; P < 0.05) and increased the content of malonaldehyde (in C40 and C60), which induced the damage in the liver and kidney as shown in the photomicrographs of hematoxylin and eosin-stained sections. The addition of ANSB060 can enhance the activity of antioxidant enzymes, and it recovered the protein synthesis in liver. Moreover, ANSB060 also ameliorated the damage of liver and kidney tissue and restored them to normal. Hence, ANSB060 had the ability to inhibit the damage induced by AFB1; it will have a great potential in industrial applications.


Asunto(s)
Aflatoxina B1/toxicidad , Bacillus subtilis/clasificación , Pollos , Huevos/normas , Enfermedades de las Aves de Corral/inducido químicamente , Probióticos/farmacología , Animales , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Enfermedad Hepática Inducida por Sustancias y Drogas/veterinaria , Femenino , Hígado/enzimología , Hígado/metabolismo , Enfermedades de las Aves de Corral/sangre , Enfermedades de las Aves de Corral/metabolismo , Enfermedades de las Aves de Corral/patología , Tocoferoles/metabolismo
3.
J Appl Microbiol ; 110(1): 147-55, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21040271

RESUMEN

AIMS: To prepare, purify and characterize an extracellular enzyme from Myxococcus fulvus ANSM068, designated as myxobacteria aflatoxin degradation enzyme (MADE), which possesses degradation activity against aflatoxin B(1) (AFB(1) ), G(1) (AFG(1) ) and M(1) (AFM(1) ) in solution. METHODS AND RESULTS: The culture supernatant of strain M. fulvus demonstrated high degradation ability against AFB(1) (71·89%), AFG(1) (68·13%) and AFM(1) (63·82%) after 48 h of incubation. An enzyme was purified from the supernatant of M. fulvus using ethanol precipitation and chromatography on DEAE-Sepharose and Superdex 75. An overall 166-fold purification of the enzyme with a recovery of 57% and a final specific activity of 569·44 × 10(3) U mg(-1) was obtained using the present purification protocol. The apparent molecular mass of MADE was estimated to be 32 kDa by SDS-PAGE. AFG(1) and AFM(1) were significantly degraded, by 96·96 and 95·80%, respectively, when treated with pure MADE (100 U ml(-1) ) produced by strain ANSM068. MADE exhibited the largest amount of activity at 35°C and pH 6·0, with Mg(2+) ions greatly promoting and Zn(2+) strongly inhibiting MADE activity. CONCLUSIONS: An aflatoxin DEGRADATION ENZYME FROM BACTERIAL ISOLATES CAN EFFECTIVELY REMOVE AFLATOXIN B(1) , G(1) AND M(1) IN SOLUTION. SIGNIFICANCE AND IMPACT OF THE STUDY: The high activity and wide temperature and pH range of MADE for the degradation of aflatoxin have promising applications in control of mycotoxins during food and feed processing.


Asunto(s)
Aflatoxinas/metabolismo , Myxococcus/enzimología , Aflatoxina B1/metabolismo , Aflatoxina M1/metabolismo , Proteínas Bacterianas/aislamiento & purificación , Proteínas Bacterianas/metabolismo
4.
Eur Rev Med Pharmacol Sci ; 21(12): 2934-2939, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28682422

RESUMEN

OBJECTIVE: To study the application timing and effect of intra-aortic balloon pump (IABP) in the emergency PCI treatment of patients with combined acute myocardial infarction (AMI) and cardiogenic shock (CS). PATIENTS AND METHODS: 84 cases of patients with combined AMI and CS under PCI in emergency treatment were randomly divided into the control group (n=42) and observational group (n=42). The control group underwent IABP again, after the invalidation of internal medicine drug treatment, while the observational group underwent IABP before the operation. We compared the effects of treatment. RESULTS: After the intervention, the averages of arterial pressure and urine volume were increased in both groups than before (p <0.05). The average of heart rate was decreased, and the improvement in the observational group was more significant (p <0.05). However, the mortality rate in the observational group during the perioperative period was decreased than the control group as well as, the success rate of off-respirator was significant (p <0.05). The comparison of IABP complication occurrence rate as well as the survival rate after 1-year follow-up between both groups was not significantly different. Additionally, whereas the NYHA grouping in two groups was gradually improved, the difference was not statistically significant between both groups. However, in the observational group, the LVEF after one-month follow-up was significantly higher than in the control group (p <0.05), but not when comparing 1-year. VEDd at each time point in two groups were also similar. CONCLUSIONS: The early IABP can improve hemodynamics of patients with combined AMI and CS under emergency PCI. It can reduce perioperative mortality rate, improve the success rate of off-respirator, but cannot increase IABP complication incidence rate while having little influence on the long-term survival rate and cardiac function indicator.


Asunto(s)
Tratamiento de Urgencia/métodos , Contrapulsador Intraaórtico/métodos , Infarto del Miocardio/cirugía , Intervención Coronaria Percutánea/métodos , Choque Cardiogénico/cirugía , Anciano , Tratamiento de Urgencia/instrumentación , Femenino , Corazón Auxiliar , Hemodinámica/fisiología , Humanos , Contrapulsador Intraaórtico/instrumentación , Masculino , Persona de Mediana Edad , Infarto del Miocardio/complicaciones , Infarto del Miocardio/fisiopatología , Intervención Coronaria Percutánea/instrumentación , Choque Cardiogénico/complicaciones , Choque Cardiogénico/fisiopatología , Factores de Tiempo
5.
Chin Med J (Engl) ; 102(2): 106-13, 1989 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2505975

RESUMEN

To investigate the effect of Calcium antagonists (Ca-An) with different tissue specificity in the development of hypertension and stroke in salt-loading SHRSP, three experiments were conducted. In experiment I (1), 50 8-week-old male SHRSP were divided into three groups and given nifedipine (NF, 32 mg/kg/day), menidipine (MN 32 mg/kg/day) and placebo (control group) respectively. In the control group 83.3% (15/18) died of stroke and 17 showed renal vascular sclerosis. Their average lifespan was 84 days. NF and MN significantly reduced systolic blood pressure (SBP), and no stroke of renal vascular sclerosis developed. In experiment I (2), 54 7-week-old male SHRSP were divided into three groups (18 in each group). They were treated with nimodipine (NM) 20 mg/kg/day, 2 mg/kg/day and placebo respectively. NM (20 mg/kg/day) markedly lowered SBP and postponed the onset of stroke. Only 11% died in 17 weeks. NM (2 mg/kg/day did not lower SBP but postpond the onset of stroke. In experiment II (1), 29 10-week-old female SHRSP were divided into three groups: Group A was given NF 32 mg/kg/day, group B was parathyroidectomized (PTX) and group C served as control. PTX group did not lower SBP but could postpone the onset of stroke. In experiment II (2), 33 male SHRSP were divided into three groups and ticated as described above in experiment II (1) (11 in each group). Seven weeks after the experiment, the brain blood flow of NF group was significantly greater (67.5%) than that of the control and PTX groups. In experiment III, 27 7-week-old male SHRSP were divided into three groups as described above in experiment I (2).(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Bloqueadores de los Canales de Calcio/uso terapéutico , Trastornos Cerebrovasculares/prevención & control , Hipertensión/prevención & control , Animales , Femenino , Masculino , Nifedipino/uso terapéutico , Nimodipina/uso terapéutico , Ratas , Ratas Endogámicas SHR
6.
Sheng Li Xue Bao ; 43(4): 400-4, 1991 Aug.
Artículo en Zh | MEDLINE | ID: mdl-1836674

RESUMEN

In order to study whether atrial natriuretic factor (ANF) is involved in the depressor effect of clonidine, microinjection of the latter into nucleus tractus solitarii (NTS) was carried out in anesthetized stroke-prone spontaneously hypertensive rats (SHRsp) and normotensive Wistar-Kyoto (WKY) rats. Each strain was randomly divided into three groups by injecting: (1) clonidine (1.0 microgram/0.2 microliter); (2) yohimbine (3.3 micrograms/0.2 microliter) followed by (1); (3) artificial cerebral spinal fluid (ACSF, 0.2 microliter) as control. A decrease of blood pressure and heart rate and a suppression of ANF release elicited by clonidine were significantly greater in SHRsp than in WKY rats. After blockade of alpha 2-receptor with yohimbine, the hypotensive effect of clonidine was blocked completely in WKY rats, but only partially in SHRsp, while the suppression effect on ANF release was eliminated in both strains. In addition, the decrease of plasma catecholamine produced by clonidine could also be blocked after yohimbine. The results suggest that ANF probably does not contribute to the depressor effect of centrally administered clonidine, while in SHRsp the decrease of plasma ANF might be a blood pressure-dependent compensatory response.


Asunto(s)
Factor Natriurético Atrial/efectos de los fármacos , Clonidina/farmacología , Animales , Factor Natriurético Atrial/metabolismo , Factor Natriurético Atrial/fisiología , Presión Sanguínea/efectos de los fármacos , Bulbo Raquídeo/metabolismo , Microinyecciones , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY
7.
Biomaterials ; 34(13): 3303-14, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23398885

RESUMEN

Enamel formation involves highly orchestrated intracellular and extracellular events; following development, the tissue is unable to regenerate, making it a challenging target for tissue engineering. We previously demonstrated the ability to trigger enamel differentiation and regeneration in the embryonic mouse incisor using a self-assembling matrix that displayed the integrin-binding epitope RGDS (Arg-Gly-Asp-Ser). To further elucidate the intracellular signaling pathways responsible for this phenomenon, we explore here the coupling response of integrin receptors to the biomaterial and subsequent downstream gene expression profiles. We demonstrate that the artificial matrix activates focal adhesion kinase (FAK) to increase phosphorylation of both c-Jun N-terminal kinase (JNK) and its downstream transcription factor c-Jun (c-Jun). Inhibition of FAK blocked activation of the identified matrix-mediated pathways, while independent inhibition of JNK nearly abolished phosphorylated-c-Jun (p-c-Jun) and attenuated the pathways identified to promote enamel regeneration. Cognate binding sites in the amelogenin promoter were identified to be transcriptionally up-regulated in response to p-c-Jun. Furthermore, the artificial matrix induced gene expression as evidenced by an increased abundance of amelogenin, the main protein expressed during enamel formation, and the CCAAT enhancer binding protein alpha (C/EBPα), which is the known activator of amelogenin expression. Elucidating these cues not only provides guidelines for the design of synthetic regenerative strategies and opportunities to manipulate pathways to regulate enamel regeneration, but can provide insight into the molecular mechanisms involved in tissue formation.


Asunto(s)
Materiales Biocompatibles/farmacología , Proteína alfa Potenciadora de Unión a CCAAT/metabolismo , Esmalte Dental/fisiología , Integrinas/metabolismo , Nanofibras/química , Proteínas Proto-Oncogénicas c-jun/metabolismo , Regeneración/efectos de los fármacos , Amelogenina/genética , Amelogenina/metabolismo , Animales , Secuencia de Bases , Línea Celular , Células Cultivadas , Esmalte Dental/efectos de los fármacos , Esmalte Dental/enzimología , Activación Enzimática/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Células Epiteliales/enzimología , Femenino , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Ratones , Datos de Secuencia Molecular , Oligopéptidos/farmacología , Péptidos/farmacología , Fosforilación/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Tensoactivos/farmacología , Regulación hacia Arriba/efectos de los fármacos
8.
J Int Med Res ; 40(6): 2124-34, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23321169

RESUMEN

OBJECTIVE: The signalling molecule protein kinase B (Akt) modulates many cellular processes. Phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathways play important roles in tumour angiogenesis. The aim of this study was to determine the role of phosphorylated Akt (pAkt) in angiogenesis and its correlation with vascular endothelial growth factor (VEGF)-A in gastric adenocarcinoma. METHODS: Tumour tissue and matched healthy gastric mucosa were obtained from patients undergoing surgical resection of gastric adenocarcinoma. Akt and pAkt were detected via Western blotting. VEGF-A, pAkt and CD34 were examined by immunohistochemistry. RESULTS: Akt and pAkt protein levels were significantly higher in gastric cancer tissue than in normal tissue (n = 48 patients). Positive VEGF-A immunostaining was significantly associated with pAkt immunostaining. Microvessel density was correlated with both VEGF-A and pAkt positivity. CONCLUSIONS: Phosphorylated Akt and VEGF-A are involved in angiogenesis of gastric adenocarcinoma, and Akt activation may contribute to angiogenesis via VEGF-A upregulation. The PI3K/Akt/VEGF signalling pathway may be involved in gastric adeno carcinoma.


Asunto(s)
Adenocarcinoma/metabolismo , Microvasos/fisiología , Neovascularización Patológica , Proteínas Proto-Oncogénicas c-akt/metabolismo , Neoplasias Gástricas/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Adenocarcinoma/irrigación sanguínea , Adulto , Anciano , Anciano de 80 o más Años , Antígenos CD34/metabolismo , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Fosfatidilinositol 3-Quinasa/metabolismo , Fosforilación , Neoplasias Gástricas/irrigación sanguínea , Regulación hacia Arriba
9.
Cell Mol Life Sci ; 62(9): 1038-46, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15868102

RESUMEN

Tuftelin-interacting protein (TFIP11) was first identified in a yeast two-hybrid screening as a protein interacting with tuftelin. The ubiquitous expression of TFIP11 suggested that it might have other functions in non-dental tissues. TFIP11 contains a G-patch, a protein domain believed to be involved in RNA binding. Using a green fluorescence protein tag, TFIP11 was found to locate in a novel subnuclear structure that we refer to as the TFIP body. An in vivo splicing assay demonstrated that TFIP11 is a novel splicing factor. TFIP11 diffuses from the TFIP body following RNase A treatment, suggesting that the retention of TFIP11 is RNA dependent. RNA polymerase II inhibitor (-amanitin and actinomycin D) treatment causes enlargement in size and decrease in number of TFIP bodies, suggesting that TFIP bodies perform a storage function rather than an active splicing function. The TFIP body may therefore represent a new subnuclear storage compartment for splicing components.


Asunto(s)
Empalme Alternativo , Proteínas Nucleares/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Adenoviridae/genética , Amanitinas/farmacología , Animales , Línea Celular , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HeLa , Humanos , Espacio Intranuclear/efectos de los fármacos , Espacio Intranuclear/metabolismo , Ratones , Microscopía Confocal , Microscopía Fluorescente , Proteínas Nucleares/genética , ARN Polimerasa II/antagonistas & inhibidores , Factores de Empalme de ARN , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Ribonucleasa Pancreática/metabolismo , Transfección , Proteínas de Transporte Vesicular/genética
10.
Int J Immunogenet ; 32(6): 421-3, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16313309

RESUMEN

Polymorphism of HLA-DPB1 was revealed with a sequencing-based typing (SBT) method in 47 unrelated healthy individuals from Yunnan Hani ethnic minority. The alleles DPB1*5901 and DPB1*7001 were detected for the first time in Chinese populations. A dendrogram showed that the Hani ethnic group belongs to the southern group of Chinese.


Asunto(s)
Antígenos HLA-DP/genética , Filogenia , Polimorfismo Genético , Pueblo Asiatico , China , Cadenas beta de HLA-DP , Humanos
11.
Tissue Antigens ; 65(3): 289-92, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15730526

RESUMEN

A sequencing-based typing of human leukocyte antigen-DPB1 (HLA-DPB1) gene was carried out in 37 unrelated healthy individuals from the Yunnan Lisu ethnic minority. A total of 12 DPB1 alleles, in which DPB1*1301 (33.3%), DPB1*0402 (16.6%), DPB1*040101 (13.8%), and DPB1*0501 (11.1%) were highly predominant, were found, and allele DPB1*200102 was found for the first time in a Chinese population. A dendrogram constructed by neighbor-joining method showed that the Lisu ethnic group belongs to East Asian cluster.


Asunto(s)
Pueblo Asiatico/genética , Evolución Molecular , Frecuencia de los Genes , Antígenos HLA-DP/genética , Alelos , China/etnología , Etnicidad/genética , Cadenas beta de HLA-DP , Humanos
12.
Biophys J ; 78(4): 1932-46, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10733972

RESUMEN

DSC was used to study the ability of glass-forming sugars to affect the gel-to-fluid phase transition temperature, T(m), of several phosphatidylcholines during dehydration. In the absence of sugars, T(m) increased as the lipid dried. Sugars diminished this increase, an effect we explain using the osmotic and volumetric properties of sugars. Sugars vitrifying around fluid phase lipids lowered T(m) below the transition temperature of the fully hydrated lipid, T(o). The extent to which T(m) was lowered below T(o) ranged from 12 degrees to 57 degrees, depending on the lipids' acyl chain composition. Sugars vitrifying around gel phase lipids raised T(m) during the first heating scan in the calorimeter, then lowered it below T(o) in subsequent scans of the sample. Ultrasound measurements of the mechanical properties of a typical sugar-glass indicate that it is sufficiently rigid to hinder the lipid gel-to-fluid transition. The effects of vitrification on T(m) are explained using the two-dimensional Clausius-Clapeyron equation to model the mechanical stress in the lipid bilayer imposed by the glassy matrix. Dextran and polyvinylpyrrolidone (PVP) also vitrified but did not depress T(m) during drying. Hydration data suggest that the large molecular volumes of these polymers caused their exclusion from the interbilayer space during drying.


Asunto(s)
Carbohidratos/química , Fosfatidilcolinas/química , Fenómenos Biofísicos , Biofisica , Rastreo Diferencial de Calorimetría , Desecación , Geles , Membrana Dobles de Lípidos/química , Fluidez de la Membrana , Modelos Químicos , Termodinámica , Ultrasonido
13.
J Struct Biol ; 131(1): 27-37, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10945967

RESUMEN

Dynamic light scattering (DLS) analysis together with atomic force microscopy (AFM) imaging was applied to investigate the supramolecular self-assembly properties of a series of recombinant amelogenins. The overall objective was to ascertain the contribution of certain structural motifs in amelogenin to protein-protein interactions during the self-assembly process. Mouse amelogenins lacking either amino- or carboxy-terminal domains believed to be involved in self-assembly and amelogenins having single or double amino acid mutations identical to those found in cases of amelogenesis imperfecta were analyzed. The polyhistidine-containingfull-length recombinant amelogenin protein [rp(H)M180] generated nanospheres with monodisperse size distribution (hydrodynamic radius of 20.7 +/- 2.9 nm estimated from DLS and 16.1 +/- 3.4 nm estimated from AFM images), comparable to nanospheres formed by full-length amelogenin rM179 without the polyhistidine domain, indicating that this histidine modification did not interfere with the self-assembly process. Deletion of the N-terminal self-assembly domain from amelogenin and their substitution by a FLAG epitope ("A"-domain deletion) resulted in the formation of assemblies with a heterogeneous size distribution with the hydrodynamic radii of particles ranging from 3 to 38 nm. A time-dependent dynamic light scattering analysis of amelogenin molecules lacking amino acids 157 through 173 and containing a hemagglutinin epitope ("B"-domain deletion) resulted in the formation of particles (21.5 +/- 6.8 nm) that fused to form larger particles of 49.3 +/- 4.3 nm within an hour. Single and double point mutations in the N-terminal region resulted in the formation of larger and more heterogeneous nanospheres. The above data suggest that while the N-terminal A-domain is involved in the molecular interactions for the formation of nanospheres, the carboxy-terminal B-domain contributes to the stability and homogeneity of the nanospheres, preventing their fusion to larger assemblies. These in vitro findings support the notion that the proteolytic cleavage of amelogenin at amino- and carboxy-terminii occurring during enamel formation influences amelogenin to amelogenin interactions during self-assembly and hence alters the structural organization of the developing enamel extracellular matrix, thus affecting enamel biomineralization.


Asunto(s)
Proteínas del Esmalte Dental/química , Proteínas del Esmalte Dental/ultraestructura , Microscopía de Fuerza Atómica , Ingeniería de Proteínas , Amelogénesis Imperfecta/genética , Amelogenina , Secuencia de Aminoácidos , Animales , Proteínas del Esmalte Dental/genética , Electroforesis en Gel de Poliacrilamida , Epítopos/química , Epítopos/genética , Epítopos/inmunología , Hemaglutininas/química , Hemaglutininas/genética , Hemaglutininas/inmunología , Humanos , Luz , Ratones , Datos de Secuencia Molecular , Tamaño de la Partícula , Mutación Puntual , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/ultraestructura , Dispersión de Radiación , Alineación de Secuencia , Eliminación de Secuencia
14.
Connect Tissue Res ; 35(1-4): 41-7, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-9084642

RESUMEN

We are interested in understanding hierarchical regulation pathways that control gene expression in developing teeth. In pursuit of the molecular basis for the regulated expression of amelogenin by developing ameloblasts during tooth formation, we isolated the murine amelogenin promoter. Analysis of this promoter will provide additional details towards the identification of signals generated through instructive-, dissimilar-germ layer interactions that are for responsible for temporal- and spatial-regulation for amelogenin gene expression. Using transgenic mice we demonstrate that a 2263 nucleotide stretch of the murine amelogenin promoter conveys appropriate temporal- and spatial-regulation for amelogenin gene expression in response to instructive-signals. These transgenic animals are useful reagents to further dissect signaling pathways responsible for regulated gene expression by terminally differentiated ameloblasts.


Asunto(s)
Ameloblastos/metabolismo , Proteínas del Esmalte Dental/genética , Regulación del Desarrollo de la Expresión Génica , Regiones Promotoras Genéticas , Células 3T3 , Amelogenina , Animales , Animales Modificados Genéticamente , Femenino , Genes Reporteros , Luciferasas/genética , Luciferasas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Diente Molar/metabolismo
15.
J Struct Biol ; 132(3): 191-200, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11243888

RESUMEN

Enamel formation is a powerful model for the study of biomineralization. A key feature common to all biomineralizing systems is their dependency upon the biosynthesis of an extracellular organic matrix that is competent to direct the formation of the subsequent mineral phase. The major organic component of forming mouse enamel is the 180-amino-acid amelogenin protein (M180), whose ability to undergo self-assembly is believed to contribute to biomineralization of vertebrate enamel. Two recently defined domains (A and B) within amelogenin appear essential for this self-assembly. The significance of these two domains has been demonstrated previously by the yeast two-hybrid system, atomic force microscopy, and dynamic light scattering. Transgenic animals were used to test the hypothesis that the self-assembly domains identified with in vitro model systems also operate in vivo. Transgenic animals bearing either a domain-A-deleted or domain-B-deleted amelogenin transgene expressed the altered amelogenin exclusively in ameloblasts. This altered amelogenin participates in the formation an organic enamel extracellular matrix and, in turn, this matrix is defective in its ability to direct enamel mineralization. At the nanoscale level, the forming matrix adjacent to the secretory face of the ameloblast shows alteration in the size of the amelogenin nanospheres for either transgenic animal line. At the mesoscale level of enamel structural hierarchy, 6-week-old enamel exhibits defects in enamel rod organization due to perturbed organization of the precursor organic matrix. These studies reflect the critical dependency of amelogenin self-assembly in forming a competent enamel organic matrix and that alterations to the matrix are reflected as defects in the structural organization of enamel.


Asunto(s)
Amelogénesis/efectos de los fármacos , Proteínas del Esmalte Dental/farmacología , Esmalte Dental/química , Amelogénesis Imperfecta/etiología , Amelogenina , Secuencia de Aminoácidos , Animales , Esmalte Dental/crecimiento & desarrollo , Esmalte Dental/ultraestructura , Proteínas del Esmalte Dental/genética , Proteínas del Esmalte Dental/ultraestructura , Expresión Génica , Inmunohistoquímica , Ratones , Ratones Endogámicos CBA , Ratones Transgénicos , Microscopía Electrónica , Minerales/metabolismo , Datos de Secuencia Molecular , Transgenes/genética , Cromosoma X
16.
Connect Tissue Res ; 38(1-4): 279-86; discussion 295-303, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-11063035

RESUMEN

Understanding the cellular and molecular events that regulate the formation of enamel is a major driving force in efforts to characterize critical events during amelogenesis. It is anticipated that through such an understanding, improvements in prevention, diagnosis and treatment-intervention into heritable and acquired diseases of enamel could be achieved. While knowledge of the precise role of an enamel-specific protein in directing the formation of inorganic crystallites remains refractory, progress has been made with other aspects of amelogenesis that can be brought to bear on the subject. One such area of progress has been with the identification of an ameloblast-lineage specific amelogenin gene promoter. This promoter can be used to direct the expression of enamel-specific proteins, as well as the expression of proteins foreign to amelogenesis, into the enamel extracellular matrix where their effect on biomineralization can be ascertained in a prospective manner. The resulting enamel from such animals can be examined by morphologic and biochemical modalities in order to identify the effect of the transgene protein on enamel crystallite formation and subsequent biomineralization. This manuscript outlines such a strategy with the potential for enhancing our understanding of amelogenesis.


Asunto(s)
Proteínas del Esmalte Dental/genética , Esmalte Dental/metabolismo , Regiones Promotoras Genéticas , Ameloblastos/metabolismo , Amelogenina , Animales , Regulación de la Expresión Génica , Genes Reporteros , Luciferasas/genética , Ratones , Ratones Transgénicos , Transgenes
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