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1.
Zhonghua Zhong Liu Za Zhi ; 43(9): 944-948, 2021 Sep 23.
Artículo en Chino | MEDLINE | ID: mdl-34530577

RESUMEN

Objective: To investigate the correlation between neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and central lymph node metastasis (CLNM) in patients with cN0 papillary thyroid microcarcinoma (PTMC). Methods: The clinicopathological data of PTMC patients confirmed by surgery and pathology in the 81st Military Hospital of People's Liberation Army from 2016 to 2019 were collected, and the relationship between preoperative NLR, PLR levels and postoperative PTMC CLNM were analyzed. Logistic regression analysis was used for multivariate analysis. Receiver operating characteristic (ROC) curve was used to determine the cutoff value of NLR and PLR. The interaction relative excess risk was used to analyze the relationship between NLR, PLR and CLNM. Results: Among 220 patients with cN0 stage PTMC, 92 were CLNM. The ROC curve showed that when the cutoff value of NLR was 2.5 and the cutoff value of PLR was 175, the highest Youden index was 0.318 and 0.264, respectively. NLR and PLR were both related to CLNM (P<0.05). The tumor long diameter, multifocality, NLR≥2.5 and PLR≥175 were independent impact factors of CLNM (P<0.05). The results of the interaction showed that the relative excess risk of the interaction was 5.531 (95%CI: 0.160, 10.901, P=0.016), the attribution ratio was 0.512 (95%CI: 0.230, 0.794, P=0.009), and the synergy index was 2.294 (95%CI: 1.492, 4.579, P=0.022), suggested that NLR and PLR had an interactive effect, and these two synergistically promoted CLNM. Conclusions: NLR and PLR are independent risk factors for cN0 stage PTMC CLNM. When NLR≥2.5 and PLR≥175, preventive central lymph node dissection should be routinely performed.


Asunto(s)
Neutrófilos , Neoplasias de la Tiroides , Carcinoma Papilar , Humanos , Ganglios Linfáticos/cirugía , Metástasis Linfática , Linfocitos , Estudios Retrospectivos , Neoplasias de la Tiroides/cirugía
2.
Opt Express ; 29(5): 7145-7157, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33726221

RESUMEN

A plasmonic-coupled, InAs-based quantum dot photodetector fabricated for mid-wave infrared photonics is reported. The detector is designed to provide a broadband absorption [full width at half maximum (FWHM) ≳ 2 µm] peaked at ∼5.5 µm, corresponding to transitions from the ground state of the quantum dot to the quasi-continuum resonance state above the quantum well. From the coupling of this transition to the surface plasma wave (SPW) excited by an Au film atop the detector, fabricated with a 1.5 µm-period, 2-dimensional array of square holes, a narrowband SPW enhancement peaked at 4.8 µm with an FWHM less than 0.5 µm is achieved. At ∼90 K, a peak responsivity enhanced ∼5× by the plasmonic coupling is observed. Simulation reveals that this enhancement corresponds to collecting ∼6% of the incident light; ∼40% of the total absorption by the SPW excitation at the peak wavelength.

3.
Nanotechnology ; 30(2): 025711, 2019 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-30411717

RESUMEN

The initial stages of the nucleation of cubic (c-) GaN in heterophase epitaxy on a Si v-groove are investigated. Growth of GaN on a nanoscale {111}-faceted v-groove fabricated into a Si(001) substrate proceeds in the hexagonal (h-) phase that induces a secondary v-groove replicating the substrate topography with two opposing {0001} facets. The secondary v-groove is then orientationally mismatched at the junction of the h-GaN facets (h -h junction) resulting in structural instability. This instability is relieved either by the formation of voids that reduce the actual junction area or by the transition to c-phase (h-c transition) suppressing further extension of the h-h junction. The distribution of voids that is locally affected by the island growth mode of h-GaN on Si(111) and the imperfection in the groove geometry impacts the initial stage of heterophase epitaxy. Primarily, The h-c transition is observed as a non-local phenomenon; it occurs homogeneously and simultaneously along the bottom of the entire secondary groove and forms a one-dimensional (1D) seed layer except for some interruptions where the h-h junction is defected by gaps or incomplete voids. Between these interruptions, epitaxy retains a single crystal but results in a series of c-GaN nanodots on the seed layer with large fluctuation in size and spacing. The adatom incorporation observed in this heterophase epitaxy is a 1D analog to the wetting of a substrate followed by the self-assembly in conventional quantum dot epitaxy. The surface morphology of the c-GaN nanodots is governed by the faceting mostly composed of (001)- and (11n)-orientations and the roughening between these facets that ultimately affect the morphology of the final top surface of the c-III-N. The interruptions interfere with the homogeneity of the h-c transition and can cause antiphase defects and mosaicity. Based on experimental results, a solution to improve these issues is proposed.

4.
ACS Appl Mater Interfaces ; 10(43): 37679-37684, 2018 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-30280889

RESUMEN

Focused ion beam (FIB) technology has become a valuable tool for the microelectronics industry and for the fabrication and preparation of samples at the micro/nanoscale. Its effects on the thermal transport properties of Si, however, are not well understood nor do experimental data exist. This paper presents a carefully designed set of experiments for the determination of the thermal conductivity of Si samples irradiated by Ga+ FIB. Generally, the thermal conductivity decreases with increasing ion dose. For doses of >1016 (Ga+/cm2), a reversal of the trend was observed due to recrystallization of Si. This report provides insight on the thermal transport considerations relevant to engineering of Si nanostructures and interfaces fabricated or prepared by FIB.

5.
Nanotechnology ; 27(37): 375707, 2016 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-27504931

RESUMEN

The top-down fabrication of an in-plane nanowire (NW) GaAs metal-oxide-semiconductor field-effect transistor (MOSFET) with a trigate oxide implemented by liquid-phase chemical-enhanced oxidation (LPCEO) is reported. A 2 µm long channel having an effective cross section ∼70 × 220 nm(2) is directly fabricated into an epitaxial n (+)-GaAs layer. This in-plane NW structure is achieved by focused ion beam (FIB) milling and hydrolyzation oxidation resulting in electronic isolation from the substrate through a semiconductor-on-insulator structure with an n (+)-GaAs/Al2O3 layer stack. The channel is epitaxially connected to the µm-scale source and drain within a single layer for a planar MOSFET to avoid any issues of ohmic contact and LPCEO to the NW. To fabricate a MOSFET, the top and the two sidewalls of the in-plane NW are oxidized by LPCEO to relieve the surface damage from FIB as well as to transform these surfaces to a ∼15 nm thick gate oxide. This trigate device has threshold voltage ∼0.14 V and peak transconductance ∼35 µS µm(-1) with a subthreshold swing ∼150 mV/decade and on/off ratio of drain current ∼10(3), comparable to the performance of bottom-up NW devices.

6.
Zhonghua Xue Ye Xue Za Zhi ; 37(7): 602-6, 2016 Jul.
Artículo en Chino | MEDLINE | ID: mdl-27535862

RESUMEN

OBJECTIVE: To evaluate the outcome of surgical resection and rituximab for treatment of primary gastric diffuse large B cell lymphoma (PGDLBCL). METHODS: Data of 83 patients with primary gastric diffuse large B cell lymphoma were reviewed retrospectively. 40 patients received surgical resection followed by chemotherapy, and the other 43 patients chemotherapy alone. The two groups were further divided into four sub- groups according to chemotherapy regimens (CHOP or R- CHOP). Overall survival (OS) and progression free survival (PFS) as two prognostic indexes were analyzed. RESULTS: The median age of these 83 cases at diagnosis was 52 years (range, 20-76 years) with a male-to-female ratio of 43 to 40. And the follow-up duration ranged from 4-59 months (mean 36 months). The 5-year PFS for the patients received surgery and chemotherapy was 66.7%. PFS for the patients received chemotherapy alone was 82.6%. And 5-year OS for these two groups was 68.4% and 85.9%,respectively. OS and PFS of chemotherapy alone group were better than the other one without statistically significance. In the combined group, the 5- year OS were 73.6% for patients received R- CHOP and 64.2% for patients received CHOP; the 5- year- PFS were 71.2% and 62.5%, respectively. Meanwhile, the 5- year OS for patients received R-CHOP and CHOP were 85.7% and 83.5%; the 5-year-PFS were 83.4% and 81.8%, respectively. The OS and PFS did not differ significantly (P>0.05) between two chemotherapy regimens. According to the Lugano stage, those who received chemotherapy alone for the patients with advanced stage (Ⅱ2, ⅡE or Ⅳ) had better OS compared with received surgery and chemotherapy. A significant difference was found between the two groups (P<0.05). However for the patients with early stage (Ⅰ or Ⅱ 2), there was no statistically significance between the two groups (P>0.05). Univariate analysis showed that age, ECOG, Lugano stage, level of LDH and IPI score (P<0.05) were factors of survival in patients with PGDLBCL. And multivariate analysis showed that IPI score was an independent prognostic factor for OS. CONCLUSION: The survival of the patients received combined surgery and chemotherapy was not superior to those received chemotherapy alone. There was no statistically significance between two different regimens for prognosis of PGDLBCL. Because of poor quality of life caused by surgery, surgery shouldn't now been recommended for the patients with PGDLBCL without operative indication. Rituximab had no positive influence on OS and PFS in most patients with PGDLBCL, but this result should be confirmed by further large sample and multi-center study.


Asunto(s)
Linfoma de Células B Grandes Difuso/terapia , Linfoma no Hodgkin/terapia , Rituximab/uso terapéutico , Neoplasias Gástricas/terapia , Adulto , Anciano , Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ciclofosfamida/uso terapéutico , Supervivencia sin Enfermedad , Doxorrubicina/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Prednisona/uso terapéutico , Pronóstico , Calidad de Vida , Estudios Retrospectivos , Vincristina/uso terapéutico , Adulto Joven
7.
J Anim Physiol Anim Nutr (Berl) ; 100(6): 1159-1168, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26671194

RESUMEN

Pulmonary arterial remodelling is a pathological characteristic of pulmonary arterial hypertension (PAH), which contributes to the development of sustained pulmonary hypertension. The aim of this study was to investigate the effects of dietary Trifolium pratense isoflavones on pulmonary vascular remodelling in experimental broiler pulmonary hypertension syndrome. Exposure to sub-thermoneutral environmental temperatures increased broiler's pulmonary hypertension syndrome incidence and raised expression levels of nitric oxide, endothelin and endothelial nitric oxide synthase. Dietary supplementation (20 mg/kg basal diet) with Trifolium pratense isoflavones reduced pulmonary hypertension syndrome incidence and improved pulmonary vascular remodelling without affecting growth performance. The beneficial effect likely came from isoflavone improved pulmonary vascular remodelling. Isoflavone induced inducible nitric oxide synthase expression, which led to increased nitric oxide level. The nitric oxide could mediate vasorelaxation in the lungs. At the same time, the expression of endothelin was downregulated by isoflavone. Dietary supplementation of Trifolium pratense isoflavone might be a potential therapeutic strategy for the treatment of pulmonary hypertension.


Asunto(s)
Pollos , Isoflavonas/farmacología , Pulmón/irrigación sanguínea , Trifolium/química , Remodelación Vascular/efectos de los fármacos , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Endotelina-1/metabolismo , Femenino , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Isoflavonas/química , Masculino , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/metabolismo
8.
Poult Sci ; 92(8): 1962-71, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23873542

RESUMEN

The present study investigated the interaction of stocking density and cool perch availability on broiler chickens raised at high ambient temperature (>30.8°C). Behavior, live performance, and the incidence of footpad and hock burns and abdominal plumage damage were investigated over a 4-wk experimental period. A total of 1,152 one-day-old Arbor Acres chicks were subjected to a 2 (cool perches) × 3 (stocking densities) factorial arrangement of treatments. From 1 d of age, birds were provided with or without cool perches at each of 3 stocking densities (12, 16, or 20 birds/m(2); low, medium, or high stocking density, respectively) and corresponded to 48, 64, and 80 birds per pen. The perch design provided 380 cm of linear perching space in each treatment pen. The results showed that high stocking density decreased the growth (P < 0.05) and welfare (P < 0.01) of broilers. Cool perch availability increased BW gain and feed conversion efficiency of broilers (P < 0.05) regardless of stocking density. The birds' use of cool perches increased with age (P < 0.01) and decreased with higher stocking density (P < 0.05). The accessibility of cool perches changed birds' behavior patterns (P < 0.01) and reduced footpad or hock burns and damage to abdominal plumage (P < 0.05). These results suggest that cool perches have a favorable effect on the performance and welfare of broilers.


Asunto(s)
Bienestar del Animal , Pollos/fisiología , Calor , Vivienda para Animales , Animales , Conducta Animal , Masculino
9.
Poult Sci ; 91(8): 1775-84, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22802167

RESUMEN

A study was conducted to determine whether water-cooled perches would be preferred by commercial broilers exposed to a hot ambient environment, and subsequently, whether utilization of these perches would improve performance and the well-being of birds, beyond those provided by normal perches. Four hundred and thirty-two 14-d-old male chickens from a commercial fast-growing strain (Arbor Acres) were housed in the following conditions: 1) cool perches, 2) normal perches, and 3) control pens with no perches. The results showed that there was greater use of cool perches than normal perches for broiler chickens during summer (F1, 4=125, P=0.0004). Cool perches increased BW gain (F2, 6=5.44, P=0.0449) and breast (F2, 24=3.31, P=0.0539) and thigh muscle yields (F2, 24=6.29, P=0.0063), while decreasing abdominal fat deposition (F2, 24=7.57, P=0.0028), cooking loss (pectoralis major, F2, 24=3.30, P=0.0542; biceps femoris, F2, 24=3.42, P=0.0493), percentage of panting birds (F2, 6=102, P<0.0001), and scores of footpad (F2, 6=122, P<0.0001) and hock (F2, 6=68.2, P<0.0001) burn, and abdominal plumage condition (F2, 6=52.0, P=0.0002), particularly toward the end of the rearing period. In contrast, normal perches hardly affected growth performance, carcass composition, meat quality and behavioral patterns, and appeared to worsen the welfare status, including footpad and hock burns and abdominal plumage condition, due to a lower occupancy rate. Cool perches offer a thermoregulatory and performance advantage to broilers exposed to a hot environment and appear to be a management strategy for improving the production and well-being of commercial broilers.


Asunto(s)
Crianza de Animales Domésticos , Pollos , Calor/efectos adversos , Vivienda para Animales , Enfermedades de las Aves de Corral/etiología , Estrés Fisiológico , Bienestar del Animal , Animales , Temperatura Corporal , Plumas/patología , Enfermedades del Pie/prevención & control , Enfermedades del Pie/veterinaria , Masculino , Tarso Animal/lesiones , Tarso Animal/patología
10.
Mol Biol Rep ; 39(11): 9903-9, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22740140

RESUMEN

Porcine reproductive and respiratory syndrome virus (PRRSV) could infect porcine alveolar macrophages (PAM), and the CD169 and CD163 are identified as critical receptors on the surface of PAM, but whether the single nucleotide polymorphisms (SNPs) of these genes could influence the infection is remain unclear. In this study, we identified totally 6 SNPs for CD169 (G1640T, C1654A, C4175T) and CD163 (G2277A, A2552G and C2700A), and evaluated their associations with PRRSV infection using two classified methods in a 524 pig population to investigate the effects of mutations on the PRRSV receptors. The pigs with genotypes of AA of CD169-C1654A, CT of CD169-C4175T and AA of CD163-A2552G appeared to resistant to the PRRSV infection by the combination of two classified results. The results provided fundamental molecular investigation to promote pig breeding with disease resistance. However, the identification of functional changes induced by SNPs and molecular mechanism were need further research.


Asunto(s)
Antígenos CD/genética , Antígenos de Diferenciación Mielomonocítica/genética , Polimorfismo de Nucleótido Simple , Síndrome Respiratorio y de la Reproducción Porcina/virología , Virus del Síndrome Respiratorio y Reproductivo Porcino/fisiología , Receptores de Superficie Celular/genética , Lectina 1 Similar a Ig de Unión al Ácido Siálico/genética , Proteínas Virales/genética , Animales , Línea Celular , Genotipo , Macrófagos Alveolares/virología , Virus del Síndrome Respiratorio y Reproductivo Porcino/genética , Porcinos
11.
J Anim Physiol Anim Nutr (Berl) ; 93(6): 754-60, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19175464

RESUMEN

Five-hundred 1-day-old broilers were randomly assigned to five groups, 100 chickens for each group. From group 1 to 3, 80, 120 and 200 mg/kg soybean peptides was added to the diets respectively; in the fourth group, 3.2 mg/kg genramycin was added; and the fifth group was the control without soybean peptides and antibiotics. At the age of 28 and 49 days, the number of goblet cells (GC), intestine intraepithelial lymphocyte, immunoglobulin A-forming cells, the ratio of villous height and crypt depth (V/C) of broiler's duodenum, jejunum and cecum were observed by the application of haematoxylin and eosin or histochemistry staining. The results indicated that soybean peptides added with 80-120 mg/kg could increase daily weight gain, the number of GC and V/C. Soybean peptides could modulate intestinal mucosal immunity of broilers.


Asunto(s)
Pollos/crecimiento & desarrollo , Inmunidad Mucosa/efectos de los fármacos , Intestinos/anatomía & histología , Intestinos/efectos de los fármacos , Proteínas de Soja/farmacología , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta , Relación Dosis-Respuesta a Droga , Factores Inmunológicos/farmacología , Aumento de Peso/efectos de los fármacos
12.
Osteoporos Int ; 20(1): 151-9, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18496637

RESUMEN

UNLABELLED: To characterize the changes in osteoprotegerin-deficient (OPG-/-) mice mandibles and the possible mandibular bone loss prevention by zoledronate. This preventive effect in the mandible differed from that in the proximal tibia and was independent of the OPG pathway. INTRODUCTION: The study aimed to characterize both the changes in the mandible in osteoprotegerin-deficient (OPG-/-) mice and possible mandibular bone loss prevention by zoledronate. METHODS: Twenty-eight 6-week-old female mice (C57BL/6J), including OPG-/- (n = 21) and wild-type (WT) (n = 7) mice, were assigned to four groups after 2 weeks of acclimatization to local vivarium conditions: wild mice with vehicle (WT group); OPG-/- mice with vehicle (OPG-/- group); and OPG-/- mice that were subcutaneously injected with either 50 or 150 microg/kg zoledronate (Zol-50 and Zol-150 groups, respectively). Mice were sacrificed at 4 weeks after these treatments and after fasting for 12 h. Sera were harvested for biochemical analyses. The right mandible and tibia of each mouse were selected for microCT analysis. Student's t-test was performed for comparisons of bone parameters at different sites in the WT group. Analysis of variance (ANOVA) was used to compare the biomarkers and bone parameters in the different treatment groups. RESULTS: Serum bone-specific alkaline phosphatase (B-ALP) and tartrate-resistant acid phosphatase 5b (TRACP-5b) were significantly decreased in WT mice as compared to the levels in the OPG-/- mice (P < 0.05). Zoledronate treatment decreased the high serum B-ALP activity observed in OPG-/- mice to the levels seen in WT mice, while serum TRACP-5b concentrations were decreased to levels even lower than those in WT mice. There were substantial variations in BMD and microstructure of the mandibular and proximal tibial trabeculae. Mandibular bone loss was less affected by OPG gene deprivation than the proximal tibia was. Both zoledronate groups showed greater BMD, trabecular BV/TV, Tb.Th, Tb.N, and Conn.D and a significant decrease in Tb.Sp and SMI as compared to the findings in OPG-/- mice (P < 0.05). However, higher apparent BMD and more compact plate-like trabeculae were observed in the mandible after treatment with zoledronate as compared to the findings in the proximal tibia. No significant differences were found in any parameter in both zoledronate groups. CONCLUSIONS: The present study showed that zoledronate could reverse the significant bone loss in mice mandibles that was induced by OPG gene deficiency. This preventive effect, which was accompanied with considerable inhibition of bone turnover, differed in the mandible and in the proximal tibia and was independent of the OPG pathway.


Asunto(s)
Pérdida de Hueso Alveolar/prevención & control , Conservadores de la Densidad Ósea/uso terapéutico , Difosfonatos/uso terapéutico , Imidazoles/uso terapéutico , Osteoprotegerina/deficiencia , Fosfatasa Ácida/sangre , Fosfatasa Alcalina/sangre , Pérdida de Hueso Alveolar/patología , Animales , Biomarcadores/sangre , Resorción Ósea/prevención & control , Esquema de Medicación , Evaluación Preclínica de Medicamentos , Femenino , Isoenzimas/sangre , Mandíbula/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Osteoprotegerina/genética , Distribución Aleatoria , Fosfatasa Ácida Tartratorresistente , Tibia/patología , Ácido Zoledrónico
13.
J Bone Miner Metab ; 25(4): 243-52, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17593495

RESUMEN

Substantial racial differences in bone mass and bone loss rate have been reported, but the extent of the difference between native Chinese women and women of different races in the United States is not clear. We used a DXA bone densitometer to measure bone mineral density (BMD), bone mineral content (BMC), bone area (BA), and volumetric BMD (vBMD) in different regions of the proximal femur in 3614 Chinese women aged 20 years and older. Regression models were chosen to best fit the changes of these parameters with increasing age. The values in their fitted curves were determined by the Cartesian coordinate numeration system. Subsequently, we compared these fitted curves to full-matched data of non-Hispanic black, non-Hispanic white, and Mexican American women reported by the third National Health and Nutrition Examination Survey (NHANES III). We found that all fitted curves of bone mass of non-Hispanic black women were significantly higher than those of Chinese, non-Hispanic white, and Mexican American women (P = 0.000). The BMD and BMC fitted curves in various regions of the hip for non-Hispanic blacks were 22%-28% and 26%-43% higher than those for Chinese women, 8.3%-13% and 7.9%-9.5% higher than those for non-Hispanic whites, and 8.8%-10% and 13%-19% higher than those for Mexican Americans, respectively. However, when the expression of difference was transformed from BMD to vBMD at the femoral neck, the difference between Chinese and non-Hispanic black women was reduced from 22% to 18% and that between Chinese and non-Hispanic white women from 7.4% to 0.8%, but the difference increased from 3.2% to 9.6% between non-Hispanic white and Mexican American women and from 13% to 17% between non-Hispanic white and non-Hispanic black women. By the age of 80 years, the accumulated bone loss rate in various regions of the proximal femur for Chinese, Mexican Americans, non-Hispanic whites, and non-Hispanic blacks were -38.9% +/- 1.8%, -34.4% +/- 3.1%, -27.8% +/- 5.9%, and -28.4% +/- 4.8%, respectively. In conclusion, bone mass in the proximal femur of native Chinese women is significantly lower, and the bone loss rate greater, than those of non-Asian women in the United States. At the femoral neck, the vBMD of Chinese women is similar to that of non-Hispanic white women.


Asunto(s)
Envejecimiento/fisiología , Densidad Ósea/fisiología , Fémur/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/etnología , China , Femenino , Humanos , Persona de Mediana Edad , Osteoporosis/etnología , Osteoporosis/patología , Distribución Aleatoria , Estados Unidos/etnología
14.
15.
Artículo en Inglés | MEDLINE | ID: mdl-10794439

RESUMEN

Photoinduced intramolecular charge transfer (ICT) of p-N,N-dimethylaminobenzoic acid (DMABOA) in AOT/cyclohexane/H2O reverse micelle was investigated and compared with that in CTAB/1-heptanol/H2O reverse micelle. It is proposed that the DMABOA molecule exists at the AOT reverse micelle water pool interface with its carboxylic group heading toward the water pool while the dimethylaminophenyl moiety buried in the micellar phase. Dual fluorescence of DMABOA that is indicative of the ICT reaction in the excited state was observed over the investigated water pool size, W of 3-17, in the AOT reverse micelle. The ICT emission of DMABOA in the AOT reverse micelle-water pool interface was found to be much weaker than that in the CTAB reverse micelle-water pool interface, and was attributed to the parallel direction of the electric field at the AOT reverse micelle-water pool interface to the charge transfer.


Asunto(s)
Ciclohexanos/química , Ácido Dioctil Sulfosuccínico/química , Micelas , Agua/química , para-Aminobenzoatos , Ácido 4-Aminobenzoico/química , Cetrimonio , Compuestos de Cetrimonio/química , Estructura Molecular
16.
Neurotoxicol Teratol ; 20(1): 69-73, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9511171

RESUMEN

Neonatal Wistar rats were exposed to lead from parturition to weaning via the milk of dams drinking 0.2% lead acetate solution. The alterations in EPSPs in areas CA1 and CA3 of hippocampal slices of 60-day-old adult rats following developmental lead exposure were studied. The results demonstrate that lead exposure in neonatal rats causes a decrease in LTP in area CA1 and an increase in LTP in area CA3. The effects of exposure to NO-generating compound sodium nitroprusside (SNP) on LTP in areas CA1 and CA3 of control and lead-exposed rats were also tested. The data demonstrate that NO causes an increase in LTP in area CA1 and no different alterations in area CA3 of lead-exposed rats. The results also demonstrate that NO may be a messenger molecule in areas CA1 and CA3. It suggests that lead might selectively interfere with specific neurochemical pathways in the hippocampus.


Asunto(s)
Hipocampo/fisiopatología , Intoxicación por Plomo/fisiopatología , Potenciación a Largo Plazo/fisiología , Óxido Nítrico/fisiología , Animales , Femenino , Hipocampo/efectos de los fármacos , Técnicas In Vitro , Plomo/metabolismo , Potenciación a Largo Plazo/efectos de los fármacos , Masculino , Penicilamina/análogos & derivados , Penicilamina/farmacología , Embarazo , Ratas , Ratas Wistar , S-Nitroso-N-Acetilpenicilamina
17.
J Comput Assist Tomogr ; 15(4): 711-5, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-2061498

RESUMEN

Most MR angiography (MRA) techniques use macroscopic blood motion to characterize the flowing spins. A different approach is represented by the use of contrast enhancement of blood pooling agents. The intravenous injection of one of these agents, namely Gd-DTPA polylysine, produces a shortening of the blood T1 below the T1 values of fat and soft tissues. In this study on experimental MRA in rabbits, we used an imaging sequence with a 90 degrees saturation pulse and a 180 degrees inversion recovery pulse. Both the saturation and inversion recovery times were adjusted to suppress the signals of soft tissues and fat. The remaining ultrashort T1 blood was imaged with a projective velocity refocused spin echo or gradient echo sequence. Magnetic resonance angiography provided excellent vessel detail with a 30-60 s acquisition time. In addition, there was no need for further processing after image acquisition because the projection was obtained immediately. The disadvantages of the technique are the need for contrast medium injection and the nonselectivity of MRA.


Asunto(s)
Medios de Contraste , Gadolinio DTPA , Imagen por Resonancia Magnética/métodos , Compuestos Organometálicos , Ácido Pentético , Polilisina , Animales , Conejos
18.
Invest Radiol ; 26(3): 213-9, 1991 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1647377

RESUMEN

To investigate the mechanism of bone changes in hypervitaminosis D3, we compared contact radiographs, microangiograms by injection of Chinese ink, and corresponding histopathologic macrosections of 66 rabbits that received different doses of vitamin D3. In early stages, radiographs showed subperiosteal bone resorption and porotic cortical bone. The corresponding microangiograms showed proliferating vessels in the periosteum and cortical bone with associated dilatation of the Haversian and Volkmann's canals. When metastatic calcification fills these intracortical caverns or the intertrabecular spaces in the metaphysis and physis, the bone shows a diffuse increased density on radiographs. A dense band in the metaphysis reflects a thickening of calcified chondromatrix due to a hypotrophy of the distal metaphyseal capillaries. Six to 12 weeks after vitamin D3 withdrawal, radiographs showed further increased density of the cortical bone, due to newly formed bone and metastatic calcification. Alternating bands of increased and decreased density in the metaphysis and physis reflect the reinvasion of normal vasculature between growth cartilage and calcified chondromatrix, with normalization of endochondral ossification.


Asunto(s)
Huesos/efectos de los fármacos , Colecalciferol/efectos adversos , Angiografía/métodos , Animales , Huesos/irrigación sanguínea , Huesos/diagnóstico por imagen , Conejos
19.
Invest Radiol ; 25(11): 1188-96, 1990 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2174836

RESUMEN

Because the pathogenesis of osteosclerosis in hypervitaminosis D is still not well elucidated, the authors experimentally studied hypervitaminosis D3 in 66 rabbits by injecting different doses of vitamin D3. Contact radiographs of bone specimens showed various signs of osteosclerosis, including dense epiphyses and metaphyses, thickened bony articular surfaces, dense metaphyseal bands, modeling defects at the metaphysis, and dense and thickened cortical bone. The corresponding pathologic sections showed that conspicuous metastatic calcification coated the trabeculae and filled bone marrow cavity and caverns in the original but porotic cortical and periosteal new bone. Rather than being resorbed, the metastatic calcifications were embedded in a thick layer of newly formed bone 6 to 14 weeks after vitamin D3 withdrawal. This study suggests that in hypervitaminosis D3, the osteoblasts and bone marrow undergo degeneration, leading to necrosis and calcification. After vitamin D3 withdrawal, osteoblasts reappear and become overactive, leading to overossification.


Asunto(s)
Enfermedades Óseas/inducido químicamente , Calcinosis/inducido químicamente , Colecalciferol/toxicidad , Osteosclerosis/inducido químicamente , Animales , Enfermedades Óseas/diagnóstico por imagen , Enfermedades Óseas/patología , Calcinosis/diagnóstico por imagen , Calcinosis/patología , Osteosclerosis/diagnóstico por imagen , Osteosclerosis/patología , Conejos , Radiografía
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