RESUMEN
Microscopic insight into interactions is a key for understanding the properties of heterogenous interfaces. We analyze local attraction in noncovalently bonded Xe-Cs^{+} aggregates and monolayers on Cu(111) as well as repulsion upon electron transfer. Using two-photon photoemission spectroscopy, scanning tunneling microscopy, and coupled cluster calculations combined with an image-charge model, we explain the intricate impact Xe has on Cs^{+}/Cu(111). We find that attraction between Cs^{+} and Xe counterbalances the screened Coulomb repulsion between Cs^{+} ions on Cu(111). Furthermore, we observe that the Cs 6s electron is repelled from Cu(111) due to xenon's electron density. Together, this yields a dual, i.e., attractive or repulsive, response of Xe depending on the positive or negative charge of the respective counterparticle, which emphasizes the importance of the Coulomb interaction in these systems.
RESUMEN
OBJECTIVE: To determine differences in masticatory muscle usage between temporomandibular joint disorders diagnostic groups. SETTING AND SAMPLE POPULATION: Seventy-one informed and consented subjects (27 men; 44 women) participated at the University at Buffalo. MATERIAL AND METHODS: Research diagnostic criteria and imaging data were used to categorize subjects according to the presence/absence +/- of TMJ disc placement (DD) and chronic pain (P) (+DD+P, n=18; +DD-P, n=14; -DD-P, n=39). Electromyographic (EMG)/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20 N bite-force (T20N , µV). Over 3 days and nights, subjects collected EMG recordings. Duty factors (DFs, % of recording time) were determined based on threshold intervals (5-9, 10-24, 25-49, 50-79, ≥80% T20N ). anova and Tukey-Kramer post hoc tests identified 1) diagnostic group differences in T20N and 2) the effects of diagnostic group, gender, time and interval on muscle DFs. RESULTS: Mean (±SE) temporalis T20N in +DD+P subjects was significantly higher (71.4±8.8 µV) than masseter T20N in these subjects (19.6±8.8 µV; p=0.001) and in -DD-P subjects (25.3±6.0 µV, p=0.0007). Masseter DFs at 5-9% T20N were significantly higher in +DD-P women (3.48%) than +DD-P men (0.85%) and women and men in both other diagnostic groups (all p<0.03), and in +DD+P women (2.00%) compared to -DD-P men (0.83%; p=0.029). Night-time DFs at 5-9% T20N in +DD-P women (1.97%) were significantly higher than in -DD-P men (0.47%) and women (0.24%; all p<0.01). CONCLUSIONS: Between-group differences were found in masticatory muscle activities in both laboratory and natural environmental settings.
Asunto(s)
Electromiografía/métodos , Músculo Masetero/fisiopatología , Monitoreo Ambulatorio/métodos , Músculo Temporal/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Adulto , Fuerza de la Mordida , Dolor Crónico/fisiopatología , Dolor Facial/fisiopatología , Femenino , Humanos , Luxaciones Articulares/fisiopatología , Masculino , Persona de Mediana Edad , Tono Muscular/fisiología , Proyectos Piloto , Factores Sexuales , Sueño/fisiología , Disco de la Articulación Temporomandibular/patología , Trastornos de la Articulación Temporomandibular/clasificación , Síndrome de la Disfunción de Articulación Temporomandibular/fisiopatología , Adulto JovenRESUMEN
OBJECTIVES: Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm³) in TMJs of three diagnostic groups. SETTING AND SAMPLE POPULATION: Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD). MATERIAL AND METHODS: Subjects (+P+DD, n=16; -P+DD, n=16; and -P-DD, n=36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q (W=work done or mechanical energy input=tractional force×distance of stress-field translation, Q=volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences. RESULTS: Mean±standard error energy density for the +P+DD group was 12.7±1.5 mJ/mm³ and significantly greater (all adjusted p<0.04) when compared to -P+DD (7.4±1.4 mJ/mm³) and -P-DD (5.8±0.9 mJ/mm³) groups. Energy densities in -P+DD and -P-DD groups were not significantly different. CONCLUSION: Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.
Asunto(s)
Cartílago Articular/fisiopatología , Trastornos de la Articulación Temporomandibular/clasificación , Adulto , Artralgia/fisiopatología , Fenómenos Biomecánicos , Simulación por Computador , Tomografía Computarizada de Haz Cónico/métodos , Dolor Facial/fisiopatología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Luxaciones Articulares/fisiopatología , Imagen por Resonancia Magnética/métodos , Masculino , Modelos Biológicos , Rango del Movimiento Articular/fisiología , Estrés Mecánico , Disco de la Articulación Temporomandibular/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Síndrome de la Disfunción de Articulación Temporomandibular/fisiopatología , Trabajo/fisiologíaRESUMEN
OBJECTIVES: Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. SETTING AND SAMPLE POPULATION: School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). MATERIAL AND METHODS: Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations. RESULTS: +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p<0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8). CONCLUSION: Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.
Asunto(s)
Músculos Masticadores/fisiopatología , Modelos Biológicos , Trastornos de la Articulación Temporomandibular/fisiopatología , Fenómenos Biomecánicos , Fuerza de la Mordida , Simulación por Computador , Femenino , Humanos , Incisivo/fisiopatología , Luxaciones Articulares/fisiopatología , Imagen por Resonancia Magnética/métodos , Masculino , Músculo Masetero/fisiopatología , Diente Molar/fisiopatología , Músculos Pterigoideos/fisiopatología , Estrés Mecánico , Músculo Temporal/fisiopatología , Disco de la Articulación Temporomandibular/fisiopatología , Trastornos de la Articulación Temporomandibular/clasificación , Síndrome de la Disfunción de Articulación Temporomandibular/fisiopatología , Tomografía Computarizada por Rayos X/métodosRESUMEN
BACKGROUND AND OBJECTIVE: Local host-modulation therapy is an emerging approach to prevent disease progression in sites with moderate periodontitis. The combination of simvastatin and alendronate would be an intriguing host-modulatory strategy because of the bone-anabolic properties of simvastatin and the antiresorptive/bone-targeting characteristics of alendronate. The objective of this study was to evaluate the effects of local administration of a simvastatin-alendronate-ß-cyclodextrin (SIM-ALN-CD) conjugate for preventing experimental periodontitis bone loss. MATERIAL AND METHODS: Twenty-four mature female Sprague-Dawley rats were treated with three, 12 µL injections, administered one week apart, bilaterally into the palatal/interproximal gingiva. The injections contained: (i) a conjugate of 0.5 mg of SIM and 3.75 mg of ALN-CD in H2 O; (ii) H2 O alone; or (iii) no treatment. One week later, the same sites were subjected to induction of experimental periodontitis by three injections (i.e. one injection administered every other day for five d) of 0.01 mg of Escherichia coli endotoxin [lipopolysaccharide (LPS)] in phosphate-buffered saline (PBS) or PBS alone. After an additional week, the rats were killed, the palates were harvested and interproximal bone volume and adjacent thickness were calculated using microcomputed tomography. Subsequently, specimens were decalcified, and interproximal histologic sections were stained with hematoxylin and eosin for evaluation of alveolar crest osteoclasts and surrounding inflammation. Values were compared among treatment groups using analysis of variance and the Kruskal-Wallis test. RESULTS: Interproximal bone volume was reduced by LPS injections (p ≤ 0.04), yet when experimental periodontitis was preceded by treatment with SIM-ALN-CD, more bone was preserved than after treatment with carrier alone (p = 0.007). While LPS caused a significant loss in bone thickness over the palatal roots (p ≤ 0.04), the injection protocol (PBS) also caused a significant loss of palatal bone thickness (p ≤ 0.03). However, prophylactic SIM-ALN-CD injections resulted in no further loss of bone thickness during experimental periodontitis. LPS injections gave histologic evidence of increased osteoclasts and subsulcular inflammation, both of which were reduced when preceded by treatment with SIM-ALN-CD (p ≤ 0.0002). CONCLUSION: The primary conclusion of this study was that locally applied SIM-ALN-CD has the potential to prevent episodes of periodontitis bone loss.
Asunto(s)
Alendronato/administración & dosificación , Pérdida de Hueso Alveolar/prevención & control , Conservadores de la Densidad Ósea/administración & dosificación , Inhibidores de Hidroximetilglutaril-CoA Reductasas/administración & dosificación , Periodontitis/prevención & control , Simvastatina/administración & dosificación , Pérdida de Hueso Alveolar/microbiología , Animales , Combinación de Medicamentos , Endotoxinas/farmacología , Escherichia coli , Femenino , Imagenología Tridimensional/métodos , Inyecciones , Lipopolisacáridos/farmacología , Enfermedades Maxilares/microbiología , Enfermedades Maxilares/prevención & control , Diente Molar/microbiología , Diente Molar/patología , Osteoclastos/efectos de los fármacos , Osteoclastos/patología , Hueso Paladar/microbiología , Hueso Paladar/patología , Periodontitis/microbiología , Premedicación , Ratas , Ratas Sprague-Dawley , Secuestrantes/administración & dosificación , Microtomografía por Rayos X/métodos , beta-Ciclodextrinas/administración & dosificaciónRESUMEN
Can markets assist by providing support for ecological restoration, and if so, under what conditions? The first step in addressing this question is to develop a consistent methodology for economic evaluation of ecological restoration projects. A risk analysis process was followed in which a system dynamics model was constructed for eight diverse case study sites where ecological restoration is currently being pursued. Restoration costs vary across each of these sites, as do the benefits associated with restored ecosystem functioning. The system dynamics model simulates the ecological, hydrological and economic benefits of ecological restoration and informs a portfolio mapping exercise where payoffs are matched against the likelihood of success of a project, as well as a number of other factors (such as project costs and risk measures). This is the first known application that couples ecological restoration with system dynamics and portfolio mapping. The results suggest an approach that is able to move beyond traditional indicators of project success, since the effect of discounting is virtually eliminated. We conclude that systems dynamic modelling with portfolio mapping can guide decisions on when markets for restoration activities may be feasible.
Asunto(s)
Conservación de los Recursos Naturales/métodos , Monitoreo del Ambiente/métodos , Modelos Teóricos , Medición de Riesgo , SudáfricaRESUMEN
The aim of this study was assess the effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Second-degree burn wounds were performed in forty-five Wistar rats, assigned into nine groups: COL-animals treated with collagen-based films; PHO-animals treated with collagen films containing empty liposomes; UAL-animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14, and 21 days the animals were euthanized. On 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltration. On the 21st day, there was reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of the usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats.
Asunto(s)
Benzofuranos/administración & dosificación , Apósitos Biológicos , Quemaduras/terapia , Colágeno/administración & dosificación , Liposomas/administración & dosificación , Cicatrización de Heridas/efectos de los fármacos , Actinas/metabolismo , Animales , Quemaduras/metabolismo , Quemaduras/patología , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Inmunohistoquímica , Inflamación/patología , Inflamación/prevención & control , Masculino , Miofibroblastos/metabolismo , Ratas , Ratas WistarRESUMEN
The PolariX TDS (Polarizable X-Band Transverse Deflection Structure) is an innovative TDS-design operating in the X-band frequency-range. The design gives full control of the streaking plane, which can be tuned in order to characterize the projections of the beam distribution onto arbitrary transverse axes. This novel feature opens up new opportunities for detailed characterization of the electron beam. In this paper we present first measurements of the Polarix TDS at the FLASHForward beamline at DESY, including three-dimensional reconstruction of the charge-density distribution of the bunch and slice emittance measurements in both transverse directions. The experimental results open the path toward novel and more extensive beam characterization in the direction of multi-dimensional-beam-phase-space reconstruction.
RESUMEN
Virtually all plants of economic importance form mycorrhizae. These absorbing organs of higher plants result from a symbiotic union of beneficial soil fungi and feeder roots. In forestry, the manipulation of fungal symbionts ecologically adapted to the planting site can increase survival and growth of forest trees, particularly on adverse sites. Vesicular-arbuscular mycorrhizae, which occur not only on many trees but also on most cultivated crops, are undoubtedly more important to world food crops. Imperatives for mycorrhizal research in forestry and agriculture are (i) the development of mass inoculum of mycorrhizal fungi, (ii) the interdisciplinary coordination with soil management, plant breeding, cultivation practices, and pest control to ensure maximum survival and development of fungal symbionts in the soil, and (iii) the institution of nursery and field tests to determine the circumstances in which mycorrhizae benefit plant growth in forestry and agri-ecosystems.
RESUMEN
The adsorption of CO on the rutile TiO(2)(110) surface was investigated using He atom scattering (HAS), high resolution electron energy loss spectroscopy (HREELS), thermal desorption spectroscopy (TDS), and different types of ab initio electronic structure calculations. The experimental and theoretical results allow to put forward a consistent picture for this rather complicated adsorbate system. At 70 K a (2x1) adlayer with a glide symmetry plane is formed, containing two molecules per unit cell which are tilted in alternate directions by about 20 degrees relative to the surface normal. For this high density phase, the theoretical calculations reveal a substantial repulsion between CO molecules on neighboring lattice sites, in accord with the results of a detailed analysis of the experimental TDS data. The CO binding energy depends strongly on coverage and varies between 0.20 eV for the saturated monolayer and 0.36 eV for isolated molecules. The CO-CO repulsion leads to the desorption of about half of the CO molecules above 70 K and the formation of low density phases. HAS gave no indication of ordered adlayers at these lower coverages. For the internal stretching vibration of the CO molecules a value of 273 meV was determined by HREELS, in very good agreement with the theoretical calculations.
RESUMEN
OBJECTIVES: To investigate genetic, biologic, and mechanical factors that affect speed of human tooth movement. Setting and Sample Population - Sixty-six maxillary canines in 33 subjects were translated distally for 84 days. MATERIAL AND METHODS: Distal compressive stresses of 4, 13, 26, 52, or 78 kPa were applied to maxillary canines via segmental mechanics. Dental casts and gingival crevicular fluid (GCF) samples were collected nine to 10 times/subject over 84 days at 1- to 14-day intervals. Three-dimensional tooth movements were measured using a microscope and each subject's series of dental casts. GCF samples were analyzed for total protein, interleukin-1beta (IL-1beta), and interleukin-1 receptor antagonist (IL-1RA). Cheek-wipe samples from 18 subjects were typed for IL-1 gene cluster polymorphisms. RESULTS: Average speeds of distal translation were 0.028 +/- 0.012, 0.043 +/- 0.019, 0.057 +/- 0.024, 0.062 +/- 0.015, and 0.067 +/- 0.024 mm/day for 4, 13, 26, 52, and 78 kPa, respectively. Most teeth moved showed no lag phase (63/66). Three factors significantly affected speed (p = 0.0391) and provided the best predictive model (R(2) = 0.691): Activity index [AI = experimental (IL-1beta/IL-1RA)/control (IL-1beta/IL-1RA)], IL-1RA in GCF, and genotype at IL-1B. CONCLUSIONS: Increased AI and decreased IL-1RA in GCF plus having > or =1 copy of allele 2 at IL-1B(+3954) were associated with faster tooth movement in humans.
Asunto(s)
Líquido del Surco Gingival/inmunología , Interleucina-1/genética , Polimorfismo Genético/genética , Técnicas de Movimiento Dental , Adolescente , Adulto , Alelos , Emparejamiento Base/genética , Niño , Diente Canino/patología , Femenino , Genotipo , Líquido del Surco Gingival/metabolismo , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Proteína Antagonista del Receptor de Interleucina 1/análisis , Interleucina-1alfa/análisis , Interleucina-1beta/análisis , Masculino , Repeticiones de Minisatélite/genética , Proteínas/análisis , Rotación , Estrés Mecánico , Factores de Tiempo , Corona del Diente/patología , Torque , Adulto JovenRESUMEN
OBJECTIVES - To determine the combined effects 1) of stress-field aspect ratio and velocity and compressive strain and 2) joint load, on temporomandibular joint (TMJ) disc mechanics. SETTING AND SAMPLE POPULATION - Fifty-two subjects (30 female; 22 male) participated in the TMJ load experiments. MATERIAL AND METHODS - In the absence of human tissue, pig TMJ discs were used to determine the effects of variables 1) on surface plowing forces, and to build a biphasic finite element model (bFEM) to test the effect of human joint loads and 2) on tissue stresses. In the laboratory, discs received a 7.6 N static load via an acrylic indenter before cyclic movement. Data were recorded and analysed using anova. To determine human joint loads, Research Diagnostic Criteria calibrated investigators classified subjects based on signs of disc displacement (DD) and pain (+DD/+pain, n = 18; +DD/-pain, n = 17; -DD/-pain, n = 17). Three-dimensional geometries were produced for each subject and used in a computer model to calculate joint loads. RESULTS - The combined effects of compressive strain, and aspect ratio and velocity of stress-field translation correlated with plowing forces (R(2) = 0.85). +DD/-pain subjects produced 60% higher joint loads (ANOVA, p < 0.05), which increased bFEM-calculated compressive strain and peak total normal stress. CONCLUSIONS - Static and dynamic variables of the stress-field and subject-dependent joint load significantly affect disc mechanics.
Asunto(s)
Disco de la Articulación Temporomandibular/fisiología , Adulto , Animales , Fenómenos Biomecánicos , Fuerza de la Mordida , Simulación por Computador , Módulo de Elasticidad , Dolor Facial/fisiopatología , Femenino , Análisis de Elementos Finitos , Humanos , Luxaciones Articulares/fisiopatología , Masculino , Músculo Masetero/fisiopatología , Fenómenos Mecánicos , Persona de Mediana Edad , Modelos Animales , Músculos del Cuello/fisiopatología , Permeabilidad , Músculos Pterigoideos/fisiopatología , Estrés Mecánico , Porcinos , Músculo Temporal/fisiopatología , Disco de la Articulación Temporomandibular/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Soporte de Peso/fisiología , Adulto JovenRESUMEN
Static mechanical analyses of the masticatory apparatus often assume that jaw muscle activity, as measured using electromyography (EMG), is linearly and constantly related to magnitude of bite force during biting, regardless of bite force-induced tooth-tipping moments. The objective of this study was to test the hypothesis that the relationship between EMG of the jaw muscles and bite force varies with the magnitude and sign of tooth-tipping moments. Seven healthy male subjects produced unilateral static occlusal forces at five biting positions, resulting in sequential changes from buccal (+) to lingual (-) tipping moments on the mandibular first molar. Jaw muscle activities were recorded bilaterally using surface (for temporalis and masseter muscles) and indwelling (for lateral pterygoid muscles) electrodes. Bite forces were recorded and controlled using custom devices. EMG versus bite force data were plotted and regression relationships were calculated for each subject, muscle and biting position. Linear regression analysis, analysis of variance and Bonferroni adjusted least significant difference tests were used to determine the effects of muscle, side (ipsilateral, contralateral) and biting position within subjects. It was found that the relationship between EMG and bite force for different tipping moments differed significantly within a subject and muscle. This was most common in the lateral pterygoid and temporalis muscles (all P=0.042), where slopes of the EMG:bite force relationship varied between 3:1 and >25:1. In the masseter muscle, the EMG:bite force relationship for different tipping moments differed significantly in one subject (P<0.008); slopes varied up to 4.6:1. In conclusion, the relationship between EMG and bite force was linear. However, the slopes of the relationship changed significantly depending on sign (+, -) and magnitude of tipping moments acting on the molars.
Asunto(s)
Oclusión Dental , Maxilares/fisiología , Músculos Masticadores/fisiología , Diente , Adulto , Análisis de Varianza , Fenómenos Biomecánicos/métodos , Fuerza de la Mordida , Electromiografía/métodos , Humanos , Maxilares/patología , Masculino , Músculos Masticadores/patologíaRESUMEN
An asymptomatic thirty-eight-year-old female developed recurrent DVT at the latter end of her first pregnancy and in the puerperium. Blood tests revealed a moderately elevated ANF (1:640) with a speckled pattern, hyperglobulinemia, and antibodies to thyroid tissues. Two months postpartum, following neurological disturbances she was found to have a patent foramen ovale and had developed paradoxical emboli to the brain causing multiple arterial occlusions. However, she also had cerebral venous occlusions as well as deep venous thromboses and pulmonary emboli, indicating a generalised prothrombotic state. Abdominal ultrasound examination revealed the presence of tumour which, on surgical removal, proved to be an ovarian carcinoma. The only antiphospholipid antibodies detectable were antibodies to mitochondria Type M5 in moderately elevated titres.
Asunto(s)
Síndrome Antifosfolípido/complicaciones , Autoanticuerpos/sangre , Cistadenocarcinoma Papilar/complicaciones , Cistadenocarcinoma Seroso/complicaciones , Mitocondrias/inmunología , Neoplasias Ováricas/complicaciones , Trombosis de la Vena/complicaciones , Adulto , Femenino , Humanos , Embolia Intracraneal/complicaciones , Embarazo , Complicaciones del Embarazo , RecurrenciaRESUMEN
UNLABELLED: Mechanical fatigue-related degeneration of the temporomandibular joint (TMJ) disc may be promoted by tractional forces. This study tested the hypotheses that tractional forces following static loading of the TMJ disc: (1) increase with compressive strain at the start of movement, and (2) are velocity-dependent during movement. Sixty-four porcine discs received a 10-N static load via an acrylic indenter for 1 or 30 sec before cyclic movement. Physical data were recorded and analyzed by ANOVA. The results showed that compressive strain and tractional forces were largest for the start of movement following 30 sec of static loading (p Asunto(s)
Cartílago Articular/fisiología
, Análisis del Estrés Dental
, Disco de la Articulación Temporomandibular/fisiología
, Análisis de Varianza
, Animales
, Fuerza Compresiva
, Fricción
, Masticación/fisiología
, Músculos Masticadores/fisiología
, Movimiento
, Contracción Muscular
, Porcinos
, Tracción
RESUMEN
A study was conducted to assess the effects of varying cage spaces on a commercial laying hen strain fed differing levels of dietary metabolizable energy (ME) for 15 wk. Four cage space allowances (342, 413, 516, and 690 cm2/hen) were combined with 3 levels of dietary ME (2,800, 2,850, and 2,900 kcal of ME/kg) in a 4 x 3 factorial arrangement. Each treatment was assigned to 6 replicate cages for a total of 72 cages in randomized complete block design. Feed intake and metabolizable energy intake were significantly (P < 0.01) greater for hens housed at 690 cm2/hen compared with those housed at 413 and 342 cm2/hen, but not those housed at 516 cm2/hen, across all dietary ME levels. Egg production and egg mass were significantly (P < 0.001) improved for hens housed at 690 cm2/ hen in contrast to other cage spaces and across all energy levels. There were no interaction effects of ME levels on laying hen performance at varying cage space except for body weight change. Hens housed at 516 cm2/ hen and fed 2,800 kcal of ME/kg exhibited the greatest weight change, which was significantly (P < 0.05) greater than those fed other levels of ME at the same cage space. Hens housed at 690 cm2/hen had significantly (P < 0.05) greater ME efficiency of egg production than hens housed at other cage spaces. Hens fed the diet with 2,900 kcal of ME/kg had significantly (P < 0.001) greater ME digestibility compared with those fed 2,800 or 2,580 kcal of ME/ kg with differences of 107 and 118 kcal of ME/kg, respectively. There were no significant effects of ME levels observed except ME digestibility, and no significant effects of cage space allowance on egg weight, hen weight, bone ash, or maintenance energy intake. It is evident that decreasing the number of birds per cage and increasing cage space allowance per hen had an overall positive effect on performance.
Asunto(s)
Pollos/fisiología , Dieta/veterinaria , Ingestión de Energía , Vivienda para Animales , Oviposición , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Femenino , Minerales/análisisRESUMEN
Little is known about physiological mechanisms that underlie the cost of reproduction. We tested the hypothesis that stress susceptibility is a cost of reproduction. In one test of our hypothesis, Drosophila melanogaster females were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster was employed as a control for reproduction. Exposure of fertile females to methoprene resulted in an increase in female reproduction and increased susceptibility to oxidative stress and starvation (compared to solvent controls). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated egg production. As a second test of our hypothesis, mated females were compared to virgin females. Mated fertile females were relatively susceptible to oxidative stress, but this relationship was not evident when mated and virgin sterile females were compared. The results of the present study support the hypothesis that stress susceptibility is a cost of reproduction.
Asunto(s)
Drosophila melanogaster/fisiología , Oocitos/fisiología , Estrés Oxidativo/fisiología , Animales , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/genética , Femenino , Radicales Libres/metabolismo , Herbicidas/farmacología , Masculino , Metopreno/farmacología , Mortalidad , Paraquat/farmacología , Reproducción , InaniciónRESUMEN
Drug resistance is one of the most important clinical problems in the treatment of ovarian cancer. This study was designed to determine whether expression of p53 could be used as a marker for predicting the response to chemotherapy of ovarian cancer. Tissue blocks were obtained from 187 patients with diagnosed untreated ovarian cancer. Paraffin sections from the primaries were immunohistochemically analysed for p53 expression. All patients underwent platinum-based chemotherapy after surgery. We analysed whether the number of chemotherapy cycles was related to survival in women with p53 positive and p53 negative ovarian cancer. 27/187 cases were p53 positive. Expression of p53 was associated with other factors of unfavourable prognosis. Patients with p53 positive tumours had a significantly worse prognosis compared with patients with p53 negative tumours (P = 0.037). There was a statistically significant dose-response effect of platinum-based chemotherapy in patients with p53 negative tumours, which could not be seen in patients with p53 positive tumours (P = 0.01 versus P = 0.553). This could also be observed in patients with residual tumour after surgery (P = 0.0001 versus P = 0.8866). Expression of p53 may be an additional useful marker in predicting response to chemotherapy. Thus, it is possible to identify a subgroup of patients who may benefit from alternative therapy regimens.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Genes p53 , Proteínas de Neoplasias/metabolismo , Neoplasias Ováricas/tratamiento farmacológico , Proteína p53 Supresora de Tumor/metabolismo , Adulto , Anciano , Carboplatino/administración & dosificación , Cisplatino/administración & dosificación , Terapia Combinada , Ciclofosfamida/administración & dosificación , Femenino , Estudios de Seguimiento , Humanos , Inmunohistoquímica , Persona de Mediana Edad , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/cirugía , Análisis de Supervivencia , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
In 1983, The German Breast Cancer Study Group, sponsored by the Federal Ministry of Research and Technology, started a prospective multicenter trial on the treatment of early breast cancer pT1 pN0 M0. Treatment consisted of initial tumorectomy with microscopically free margins and lower axillary dissection. After conformation of a pT1 pN0-stage, additional treatment was either mastectomy or adjuvant radiotherapy (50 Gy in 25 fractions to the entire breast plus 12 Gy electron boost). In medially located tumors, the parasternal and supraclavicular area was also irradiated with 50 Gy. A randomization between both treatment modalities was initially planned but was not feasible and abandoned. Nearly all patients were treated according to their own choice. From November 1983 through December 1989, 1119 patients were recruited. Eighty-three were excluded from the protocol. Out of the remaining 1036 patients, 733 (71%) underwent breast preservation and 303 (29%) mastectomy. A detailed pathohistological examination of all tumorectomy specimens was performed in a pathologic reference center. Oncogen overexpression was evaluated by immunohistological detection of the transmembrane protein p-185 (corresponding to c-erb-B2) in 425 cases. After a median follow-up of 48 months, the frequency of local recurrences (4.7%), regional recurrences (1%), and distant metastases (5.4%) was the same in the breast preservation group and the mastectomy group. The 3-year disease-free survival was 90% after breast preservation and 88% after mastectomy (p = 0.21). In the breast preserving group, 24 patients with microscopically involved margins had a poorer disease-free survival than the study group (75% vs 90% after 3 years). The width of the margins had no impact on prognosis. Other prognostic factors in an univariate and multivariate analysis were tumor size and tumor grade. Age, menopausal status, hormone receptor status, histological tumor type, and treatment (mastectomy vs breast preservation) were not significant. P-185-expression was dependent on tumor grade and was the strongest prognostic factor in an univariate and multivariate analysis (p less than 0.001). The results emphasize the central role of tumor grade for prognosis and suggest the independent prognostic significance of the c-erb-B2 oncogen (corresponding to p-185) in pN0-patients.
Asunto(s)
Neoplasias de la Mama/cirugía , Escisión del Ganglio Linfático , Mastectomía Radical , Mastectomía Segmentaria , Proteínas Proto-Oncogénicas/análisis , Adenocarcinoma/epidemiología , Adenocarcinoma/radioterapia , Adenocarcinoma/cirugía , Adenocarcinoma Mucinoso/epidemiología , Adenocarcinoma Mucinoso/radioterapia , Adenocarcinoma Mucinoso/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/radioterapia , Carcinoma/epidemiología , Carcinoma/radioterapia , Carcinoma/cirugía , Carcinoma Papilar/epidemiología , Carcinoma Papilar/radioterapia , Carcinoma Papilar/cirugía , Terapia Combinada , Femenino , Humanos , Persona de Mediana Edad , Cuello , Pronóstico , Estudios Prospectivos , Proteínas Proto-Oncogénicas c-myc/análisis , Receptor ErbB-2RESUMEN
UNLABELLED: This study compared the effects of porcine myocardial stunning on the uptake of [18F]-fluorodeoxyglucose (FDG) at 24 hr and 7 days after reperfusion. Prior studies in animals subjected to severe myocardial ischemia have shown a sustained increase in FDG uptake relative to perfusion (FDG/MBF). The time course of recovery of FDG/MBF relative to function poststunning, however, has not been well characterized. METHODS: Stunning was induced in eight swine by partially occluding the LAD artery for 20 min. At 1 and 7 days postreperfusion, function was assessed by two-dimensional echocardiography and PET studies were obtained with FDG and either 15O-water or 13N-ammonia. Blood flow by microspheres was determined at baseline, during ischemia and after stunning. Myocardial uptake of FDG relative to blood flow on matching images (FDG/MBF) was calculated for all ROIs and expressed as a ratio of LAD to non-LAD areas. RESULTS: After stunning, left ventricular ejection fraction (LVEF) increased from 42% +/- 10% on Day 1 to 52% +/- 6% on Day 7 (p < 0.05). At Day 1, myocardial blood flow was 0.60 +/- 0.10 ml/min/g in LAD and 0.67 +/- 0.16 in non-LAD regions and neither differed at Day 7. The magnitude of FDG/MBF in the LAD region when normalized to the non-LAD region was 1.29 +/- 0.16 on Day 1 and 1.09 +/- 0.08 on Day 7 (p < 0.05) and was inversely proportional to global measures of LVEF (r2 = 0.61; p < 0.005). CONCLUSION: The severity of postischemic LV dysfunction at 1 and 7 days after stunning correlates with the degree of enhanced regional glucose uptake as estimated by PET. Both normalize within 7 days, suggesting that metabolic and functional abnormalities within completely reperfused myocardium recover in parallel.