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1.
Ecology ; 99(11): 2592-2604, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30198573

RESUMEN

Effects of species diversity on population and community stability (or more precisely, the effects of species richness on temporal variability) have been studied for several decades, but there have been no large-scale tests in natural communities of predictions from theory. We used 91 data sets including plants, fish, small mammals, zooplankton, birds, and insects, to examine the relationship between species richness and temporal variability in populations and communities. Seventy-eight of 91 data sets showed a negative relationship between species richness and population variability; 46 of these relationships were statistically significant. Only five of the 13 positive richness-population variability relationships were statistically significant. Similarly, 51 of 91 data sets showed a negative relationship between species richness and community variability; of these, 26 were statistically significant. Seven of the 40 positive richness-community-variability relationships were statistically significant. We were able to test transferability (i.e., the predictive ability of models for sites that are spatially distinct from sites that were used to build the models) for 69 of 91 data sets; 35 and 31 data sets were transferable at the population and community levels, respectively. Only four were positive at the population level, and two at the community level. We conclude that there is compelling evidence of a negative relationship between species richness and temporal variability for about one-half of the ecological communities we examined. However, species richness explained relatively little of the variability in population or community abundances and resulted in small improvements in predictive ability.


Asunto(s)
Biodiversidad , Ecosistema , Animales , Plantas , Dinámica Poblacional , Zooplancton
2.
Br J Cancer ; 112(5): 825-31, 2015 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-25584487

RESUMEN

BACKGROUND: Few studies have investigated the effects of exercise on modulation of host factors in cancer patients. We investigated the efficacy of chronic aerobic training on multiple host-related effector pathways in patients with solid tumours. PATIENTS AND METHODS: Paired peripheral blood samples were obtained from 44 patients with solid tumours receiving cytotoxic therapy and synthetic erythropoietin (usual care; n=21) or usual care plus supervised aerobic training (n=23) for 12 weeks. Samples were characterised for changes in immune, cytokine and angiogenic factors, and metabolic intermediates. Aerobic training consisted of three supervised cycle ergometry sessions per week at 60% to 100% of peak oxygen consumption (VO2peak), 30-45 min per session, for 12 weeks following a nonlinear prescription. RESULTS: The between-group delta change in cardiopulmonary function was +4.1 ml kg (-1) min(-1), favouring aerobic training (P<0.05). Significant pre-post between-group differences for five cytokine and angiogenic factors (HGF, IL-4, macrophage inflammatory protein-1ß (MIP-1ß), vascular endothelial growth factor (VEGF), and TNF-α) also favour the aerobic training group (P's<0.05). These reductions occurred in conjunction with nonsignificant group differences for T lymphocytes CD4(+), CD8(+), and CD8(+)/CD45RA (P<0.10). For these factors, circulating concentrations generally increased from baseline to week 12 in the aerobic training group compared with decreases or no change in the usual care group. No significant changes in any metabolic intermediates were observed. CONCLUSIONS: Aerobic training alters host availability of select immune-inflammatory effectors in patients with solid tumours; larger confirmatory studies in more homogenous samples are warranted.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biomarcadores de Tumor/sangre , Eritropoyetina/administración & dosificación , Terapia por Ejercicio/métodos , Neoplasias/terapia , Fenómenos Fisiológicos Cardiovasculares , Ensayos Clínicos como Asunto , Terapia Combinada , Eritropoyetina/uso terapéutico , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/sangre , Consumo de Oxígeno , Proyectos Piloto
3.
Diabetologia ; 55(2): 321-30, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22065088

RESUMEN

AIMS/HYPOTHESIS: Insulin resistance (IR) improves with weight loss, but this response is heterogeneous. We hypothesised that metabolomic profiling would identify biomarkers predicting changes in IR with weight loss. METHODS: Targeted mass spectrometry-based profiling of 60 metabolites, plus biochemical assays of NEFA, ß-hydroxybutyrate, ketones, insulin and glucose were performed in baseline and 6 month plasma samples from 500 participants who had lost ≥4 kg during Phase I of the Weight Loss Maintenance (WLM) trial. Homeostatic model assessment of insulin resistance (HOMA-IR) and change in HOMA-IR with weight loss (∆HOMA-IR) were calculated. Principal components analysis (PCA) and mixed models adjusted for race, sex, baseline weight, and amount of weight loss were used; findings were validated in an independent cohort of patients (n = 22). RESULTS: Mean weight loss was 8.67 ± 4.28 kg; mean ∆HOMA-IR was -0.80 ± 1.73, range -28.9 to 4.82). Baseline PCA-derived factor 3 (branched chain amino acids [BCAAs] and associated catabolites) correlated with baseline HOMA-IR (r = 0.50, p < 0.0001) and independently associated with ∆HOMA-IR (p < 0.0001). ∆HOMA-IR increased in a linear fashion with increasing baseline factor 3 quartiles. Amount of weight loss was only modestly correlated with ∆HOMA-IR (r = 0.24). These findings were validated in the independent cohort, with a factor composed of BCAAs and related metabolites predicting ∆HOMA-IR (p = 0.007). CONCLUSIONS/INTERPRETATION: A cluster of metabolites comprising BCAAs and related analytes predicts improvement in HOMA-IR independent of the amount of weight lost. These results may help identify individuals most likely to benefit from moderate weight loss and elucidate novel mechanisms of IR in obesity.


Asunto(s)
Aminoácidos de Cadena Ramificada/química , Resistencia a la Insulina , Adulto , Algoritmos , Aminoácidos/química , Biomarcadores/metabolismo , Índice de Masa Corporal , Peso Corporal , Estudios de Cohortes , Femenino , Humanos , Masculino , Espectrometría de Masas/métodos , Persona de Mediana Edad , Análisis de Componente Principal , Pérdida de Peso
4.
Diabetologia ; 53(4): 757-67, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20076942

RESUMEN

AIMS/HYPOTHESIS: Insulin resistance (IR) is associated with obesity, but can also develop in individuals with normal body weight. We employed comprehensive profiling methods to identify metabolic events associated with IR, while controlling for obesity. METHODS: We selected 263 non-obese (BMI approximately 24 kg/m2) Asian-Indian and Chinese men from a large cross-sectional study carried out in Singapore. Individuals taking medication for diabetes or hyperlipidaemia were excluded. Participants were separated into lower and upper tertiles of IR based on HOMA indices of < or =1.06 or > or =1.93, respectively. MS-based metabolic profiling of acylcarnitines, amino acids and organic acids was combined with hormonal and cytokine profiling in all participants. RESULTS: After controlling for BMI, commonly accepted risk factors for IR, including circulating fatty acids and inflammatory cytokines, did not discriminate the upper and lower quartiles of insulin sensitivity in either Asian- Indian or Chinese men. Instead, IR was correlated with increased levels of alanine, proline, valine, leucine/isoleucine, phenylalanine, tyrosine, glutamate/glutamine and ornithine, and a cluster of branched-chain and related amino acids identified by principal components analysis. These changes were not due to increased protein intake by individuals in the upper quartile of IR. Increased abdominal adiposity and leptin, and decreased adiponectin and IGF-binding protein 1 were also correlated with IR. CONCLUSIONS/INTERPRETATION: These findings demonstrate that perturbations in amino acid homeostasis, but not inflammatory markers or NEFAs, are associated with IR in individuals of relatively low body mass.


Asunto(s)
Índice de Masa Corporal , Resistencia a la Insulina/fisiología , Adiponectina/sangre , Adulto , Aminoácidos/sangre , Aminoácidos/metabolismo , Pueblo Asiatico , Glucemia/metabolismo , Colesterol/sangre , Estudios Transversales , Demografía , Factor Estimulante de Colonias de Granulocitos y Macrófagos/sangre , Humanos , India , Insulina/sangre , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Interleucinas/sangre , Estilo de Vida , Lípidos/sangre , Masculino , Espectrometría de Masas , Persona de Mediana Edad , Selección de Paciente , Grupos Raciales , Factores de Riesgo , Singapur/epidemiología , Población Blanca
5.
Med Phys ; 47(6): 2392-2407, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32145076

RESUMEN

PURPOSE: Our aim was to develop a high-quality, mobile cone-beam computed tomography (CBCT) scanner for point-of-care detection and monitoring of low-contrast, soft-tissue abnormalities in the head/brain, such as acute intracranial hemorrhage (ICH). This work presents an integrated framework of hardware and algorithmic advances for improving soft-tissue contrast resolution and evaluation of its technical performance with human subjects. METHODS: Four configurations of a CBCT scanner prototype were designed and implemented to investigate key aspects of hardware (including system geometry, antiscatter grid, bowtie filter) and technique protocols. An integrated software pipeline (c.f., a serial cascade of algorithms) was developed for artifact correction (image lag, glare, beam hardening and x-ray scatter), motion compensation, and three-dimensional image (3D) reconstruction [penalized weighted least squares (PWLS), with a hardware-specific statistical noise model]. The PWLS method was extended in this work to accommodate multiple, independently moving regions with different resolution (to address both motion compensation and image truncation). Imaging performance was evaluated quantitatively and qualitatively with 41 human subjects in the neurosciences critical care unit (NCCU) at our institution. RESULTS: The progression of four scanner configurations exhibited systematic improvement in the quality of raw data by variations in system geometry (source-detector distance), antiscatter grid, and bowtie filter. Quantitative assessment of CBCT images in 41 subjects demonstrated: ~70% reduction in image nonuniformity with artifact correction methods (lag, glare, beam hardening, and scatter); ~40% reduction in motion-induced streak artifacts via the multi-motion compensation method; and ~15% improvement in soft-tissue contrast-to-noise ratio (CNR) for PWLS compared to filtered backprojection (FBP) at matched resolution. Each of these components was important to improve contrast resolution for point-of-care cranial imaging. CONCLUSIONS: This work presents the first application of a high-quality, point-of-care CBCT system for imaging of the head/ brain in a neurological critical care setting. Hardware configuration iterations and an integrated software pipeline for artifacts correction and PWLS reconstruction mitigated artifacts and noise to achieve image quality that could be valuable for point-of-care detection and monitoring of a variety of intracranial abnormalities, including ICH and hydrocephalus.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Cabeza , Algoritmos , Artefactos , Encéfalo/diagnóstico por imagen , Cabeza/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Fantasmas de Imagen
6.
Science ; 161(3848): 1338-9, 1968 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-17831344

RESUMEN

Potassium-argon dates obtained from extrusives collected on a traverse across the Mid-Atlantic Ridge at 45 degrees N are consistent with the hypothesis of ocean-floor spreading. The dates suggest a spreading rate in the range of 2.6 to 3.2 centimeters per year near the axis of the ridge; the rate agrees with that computed from fission-track dating of basalt glasses. Additional data for a basalt collected 62 kilometers west of the axis gives a spreading rate of 0.8 centimeter per year, which is similar to the rate inferred from magnetic anomaly patterns in the area. Reasons for the difference in calculated spreading rates are discussed.

7.
Science ; 167(3918): 479-80, 1970 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-17781461

RESUMEN

A K-Ar age of 2300 x 10(6) years has been determined for a sample of type A crystalline rock (57,34). The presence of an anomalously large quantity of 4 degrees Ar, in a sample of type C breccia (65,35) precluded the calculation of its K-Ar age. Both of the rock types are characterized by low Rb/Sr ratios and consequently low (87)Sr/(86)Sr values. The U-Th-Pb results for a sample of type D fines (84,33) yield a (207)Pb/(206)Pb age of 4760 x 10(6) years, but ages based on U-Pb and Th-Pb ratios are anomalously high. Isotopic compositions of Li, K, Rb, Sr, U, and Th are very close to the accepted values for terrestrial materials.

8.
Mol Biol Cell ; 7(8): 1153-66, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8856661

RESUMEN

RXR is a nuclear receptor that plays a central role in cell signaling by pairing with a host of other receptors. Previously, 9-cis-retinoic acid (9cRA) was defined as a potent RXR activator. Here we describe a unique RXR effector identified from organic extracts of bovine serum by following RXR-dependent transcriptional activity. Structural analyses of material in active fractions pointed to the saturated diterpenoid phytanic acid, which induced RXR-dependent transcription at concentrations between 4 and 64 microM. Although 200 times more potent than phytanic acid, 9cRA was undetectable in equivalent amounts of extract and cannot be present at a concentration that could account for the activity. Phytanic acid, another phytol metabolite, was synthesized and stimulated RXR with a potency and efficacy similar to phytanic acid. These metabolites specifically displaced [3H]-9cRA from RXR with Ki values of 4 microM, indicating that their transcriptional effects are mediated by direct receptor interactions. Phytol metabolites are compelling candidates for physiological effectors, because their RXR binding affinities and activation potencies match their micromolar circulating concentrations. Given their exclusive dietary origin, these chlorophyll metabolites may represent essential nutrients that coordinate cellular metabolism through RXR-dependent signaling pathways.


Asunto(s)
Fitol/metabolismo , Receptores de Ácido Retinoico/metabolismo , Factores de Transcripción/metabolismo , Animales , Células CHO , Bovinos , Cricetinae , Grasas de la Dieta/metabolismo , Ácidos Grasos Esenciales/aislamiento & purificación , Ácidos Grasos Esenciales/metabolismo , Técnicas In Vitro , Ligandos , Ácido Fitánico/análogos & derivados , Ácido Fitánico/aislamiento & purificación , Ácido Fitánico/metabolismo , Ácido Fitánico/farmacología , Receptores de Ácido Retinoico/efectos de los fármacos , Enfermedad de Refsum/metabolismo , Receptores X Retinoide , Transducción de Señal , Factores de Transcripción/efectos de los fármacos , Tretinoina/sangre , Tretinoina/metabolismo
9.
Handb Clin Neurol ; 140: 379-395, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28187811

RESUMEN

A neurocatastrophe or severe brain injury (SBI) is a central nervous system insult associated with a high likelihood of death or severe disability. While many etiologic processes may lead to SBI, the most common and best-studied clinical paradigms are traumatic brain injury and anoxic-ischemic encephalopathy following cardiac arrest. Clinical phenotypes following SBI include acute and chronic disorders of consciousness as well as a range of cognitive and behavioral impairments. A fundamental task for medical teams working in the acute phase is to estimate SBI recovery probabilities with the highest degree of accuracy possible. Predictions made on the basis of single features or variables lack discrimination and are generally supplanted by multivariable models that combine clinical, imaging, and laboratory data into tractable scoring systems. Yet existing scores fail to classify outcomes with the accuracy that would support individual patient-level decision making. Improved prognostication will likely depend on the use of molecular and imaging data that capture unique biologic features in individual patients with SBI. The integration of these additional layers of information will require iterative computational approaches.


Asunto(s)
Lesiones Encefálicas/complicaciones , Humanos , Pronóstico
10.
J Mol Biol ; 262(4): 407-12, 1996 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-8893852

RESUMEN

The expression of eukaryotic genes in Escherichia coli is one of the most frequently used tools of modern science. The arginine codon AGA is a common codon in eukaryotic genes but is particularly rare in E. coli. We report here 36 to 42% misincorporation of lysine at three AGA codons in a well-expressed protein. This misincorporation yields a protein whose electrospray mass spectrum (ESMS) shows peaks at the expected mass (M), M-28, M-56 and M-84 with intensities representing 34.5(+/-0.7), 37.5(+/-1.1), 21.2(+/-1.7) and 6.6(+/-0.5) % of the total intensity, respectively. Replacement of either all three AGA codons or the two closest to the 3' end of the gene by the more common CGC arginine codon gave a protein with a single ESMS peak. Misincorporation could also be eliminated by the co-expression of the tRNA(UCL)Arg gene, argU. These studies demonstrate that misincorporation of amino acids at rare codons of recombinant proteins can be far higher than previously thought.


Asunto(s)
Arginina/química , Codón , Lisina/química , Proteínas Recombinantes de Fusión/genética , Secuencia de Aminoácidos , Secuencia de Bases , Escherichia coli , Espectrometría de Masas , Datos de Secuencia Molecular , Proteínas Recombinantes de Fusión/química
11.
Bioinformatics ; 20 Suppl 1: i303-10, 2004 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-15262813

RESUMEN

MOTIVATION: In silico experiments necessitate the virtual organization of people, data, tools and machines. The scientific process also necessitates an awareness of the experience base, both of personal data as well as the wider context of work. The management of all these data and the co-ordination of resources to manage such virtual organizations and the data surrounding them needs significant computational infra-structure support. RESULTS: In this paper, we show that (my)Grid, middleware for the Semantic Grid, enables biologists to perform and manage in silico experiments, then explore and exploit the results of their experiments. We demonstrate (my)Grid in the context of a series of bioinformatics experiments focused on a 1.5 Mb region on chromosome 7 which is deleted in Williams-Beuren syndrome (WBS). Due to the highly repetitive nature of sequence flanking/in the WBS critical region (WBSCR), sequencing of the region is incomplete leaving documented gaps in the released sequence. (my)Grid was used in a series of experiments to find newly sequenced human genomic DNA clones that extended into these 'gap' regions in order to produce a complete and accurate map of the WBSCR. Once placed in this region, these DNA sequences were analysed with a battery of prediction tools in order to locate putative genes and regulatory elements possibly implicated in the disorder. Finally, any genes discovered were submitted to a range of standard bioinformatics tools for their characterization. We report how (my)Grid has been used to create workflows for these in silico experiments, run those workflows regularly and notify the biologist when new DNA and genes are discovered. The (my)Grid services collect and co-ordinate data inputs and outputs for the experiment, as well as much provenance information about the performance of experiments on WBS. AVAILABILITY: The (my)Grid software is available via http://www.mygrid.org.uk


Asunto(s)
Algoritmos , Mapeo Cromosómico/métodos , Predisposición Genética a la Enfermedad/genética , Análisis de Secuencia de ADN/métodos , Programas Informáticos , Interfaz Usuario-Computador , Síndrome de Williams/genética , Gráficos por Computador , Internet
12.
Int J Biochem Cell Biol ; 28(12): 1319-26, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9022290

RESUMEN

The aim of the work is to identify and characterize the hemoglobins found in B6C3F1 mice using mass spectrometry. The primary structures are compared to those reported for BALB/c mice. Individual hemoglobin chains were isolated by reverse-phase high performance liquid chromatography (RP-HPLC). The molecular masses of the globins were determined using electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI). The purified globin chains were enzymatically cleaved and the resulting peptides were separated by RP-HPLC. The chains were identified by N-terminal sequencing and mass spectrometry (MALDI). Selected peptides were analysed by Edman degradation. ESI analysis indicates that B6C3F1 mice have two alpha-globin chains (alpha-1 and alpha-2) and at least three beta-globin chains, beta-1, beta-2 and beta-3. This is one additional alpha- and one additional beta-globin chain than reported in the literature for BALB/c mice. Mass and sequence analysis of enzymatically generated peptides showed variations in the amino acid sequence in the alpha-1, alpha-2, beta-2 and beta-3 chains compared to the BALB/c mouse hemoglobins (alpha, beta (minor) and beta (major)). The study showed that mass spectrometry in combination with traditional protein chemistry is able to identify and locate minor protein sequence variations.


Asunto(s)
Hemoglobinas/análisis , Hemoglobinas/genética , Secuencia de Aminoácidos , Animales , Cromatografía Líquida de Alta Presión , Globinas/genética , Globinas/aislamiento & purificación , Hemoglobinas/química , Masculino , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Mapeo Peptídico , Análisis de Secuencia , Homología de Secuencia de Aminoácido , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
13.
Free Radic Biol Med ; 21(1): 117-21, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8791100

RESUMEN

The periplasmic Cu,Zn superoxide dismutase has been purified to homogeneity by a procedure, which depended upon osmotic shock followed by two chromatographic columns. Its subunit weight, determined by electrospray ionization mass spectrometry, was found to be 15,737 +/- 1.6. The second derivative ultraviolet spectrum indicated a lack of tryptophan. The amino acid composition as well as a partial N-terminal amino acid sequence is reported. The specific activity was 3700 U/mg and the corresponding copper content was 0.77 atoms Cu/subunit. The enzyme was quite unstable and overnight dialysis against EDTA or even prolonged dialysis against neutral phosphate buffer caused partial loss of activity and of copper and visible precipitation. It is likely that some losses occurred during the isolation procedure, and if these could have been prevented the copper content would have been 1.0 Cu/subunit and the specific activity would have been 4800 U/mg. It now appears likely that gram negative bacteria will commonly be found to contain a periplasmic Cu,Zn SOD.


Asunto(s)
Escherichia coli/enzimología , Superóxido Dismutasa/aislamiento & purificación , Superóxido Dismutasa/metabolismo , Secuencia de Aminoácidos , Aminoácidos/análisis , Cromatografía DEAE-Celulosa , Cromatografía Líquida de Alta Presión , Cobre/análisis , Electroforesis en Gel de Poliacrilamida , Humanos , Cinética , Datos de Secuencia Molecular , Espectrofotometría Atómica , Espectrofotometría Ultravioleta , Superóxido Dismutasa/química
14.
Soc Sci Med ; 18(9): 767-74, 1984.
Artículo en Inglés | MEDLINE | ID: mdl-6427935

RESUMEN

This study examined factors contributing to variability in the cost-effectiveness of managing hypertension using the Weinstein and Stason methodology. Empirical analysis was based on resource use and blood pressure data from 160 persons ages 25-64 in an urban community family practice center in 1976. The exploratory study presented results on blood pressure reduction, annual treatment costs, the importance of different cost factors, variability in management costs and potentials for increasing cost-effectiveness. For males cost-effectiveness estimates were similar to those of Weinstein and Stason , while the results for women were somewhat different due to less cost-effectiveness in hypertension management for older women. With small modifications in current Family Practice procedures the cost-effectiveness of managing hypertension appears to be able to be increased in many cases by as much as one-third.


Asunto(s)
Centros Comunitarios de Salud/economía , Hipertensión/economía , Adulto , Análisis Costo-Beneficio , Medicina Familiar y Comunitaria , Femenino , Humanos , Masculino , Michigan , Persona de Mediana Edad
15.
Theriogenology ; 39(2): 373-80, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16727217

RESUMEN

Simultaneous injections of prostaglandin F2alpha (PGF) and gonadotropin releasing hormone (GnRH) or saline were given to 32 diestrous dairy cows to test the ability of GnRH to improve estrous and ovulation synchrony beyond that of PGF alone. Cows were randomly assigned to receive PGF on Day 8 or Day 10 of the estrous cycle (estrus = Day 0), and all cows were further assigned to simultaneous injection of GnRH or saline. Corpus luteum (CL) regression, return to estrus and follicular activity were monitored by plasma progesterone assay, twice-daily estrous detection and ultrasonographic examination, respectively. Plasma progesterone concentrations declined to <1.0 ng/ml at 24 hours after PGF in all cows and were not affected by GnRH. Gonadotropin releasing hormone inducted premature ovulation or delayed return to estrus in 7 of 8 cows treated with PGF/GnRH on Day 8 and 3 of 8 cows treated with PGF/GnRH on Day 10. Further, cows with premature GnRH-induced ovulations failed to develop and maintain a fully functional CL, and all returned to estrus 7 to 13 days after the induced ovulation. These data indicate that GnRH administered simultaneously with a luteolytic dose of PGF disrupts follicular dynamics and induces premature ovulation or delays normal return to estrus and, therefore, does not improve the synchrony of estrus and ovulation achieved with PGF alone.

16.
Theriogenology ; 39(2): 381-7, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16727218

RESUMEN

Simultaneous injections of PGF and FSH or saline were given to 32 Holstein cows to test their combined ability to improve estrous and ovulation synchrony beyond that of PGF alone. All the cows were randomly assigned to receive PGF on either Day 8 or Day 10 of the estrous cycle (estrus = Day 0), and all the cows in each group were further assigned to simultaneous injection of either FSH or saline. Regression of the corpus luteum (CL), return to estrus and follicular activity were monitored by plasma progesterone assay, twice-daily estrous detection and ultrasonographic examination, respectively. Plasma progesterone concentrations declined to <1.0 ng/ml at 24 hours after PGF treatment in all the cows and FSH did not affect this decline. Return to estrus was not affected by FSH treatment in cows treated on Day 8 or Day 10; however, FSH disrupted normal follicular activity and either delayed normal ovulation following estrus or induced premature ovulation or cyst formation in 4 of 8 PGF/FSH (Day 8) cows and 5 of 8 PGF/FSH (Day 10) cows. These data indicate that exogenous FSH administered simultaneously with a luteolytic does of PGF does not maintain viability of large, dominant follicles and, therefore, is not an effective method for the synchronization of estrus and ovulation.

17.
Am J Vet Res ; 56(3): 398-402, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7771711

RESUMEN

The bioequivalency of 2 gondatropin-releasing hormone (GnRH) preparations, gonadorelin diacetate tetrahydrate and gonadorelin semicarbonate, was compared on the basis of luteinizing hormone (LH)-releasing ability of the 2 products in diestrous dairy cows. Twenty-four cycling, nonlactating Holstein cows were subjected to a double prostaglandin estrus synchronization treatment to simultaneously control stage of the estrous cycle and time factors as potential variables effecting LH responses to the treatments being studied. Circulating progesterone concentration was determined to verify stage of cycle at strategic times throughout the study. Twelve days after the second prostaglandin treatment, all cows were randomly assigned to 1 of 2 groups (n = 12). Each group of 12 cows received single doses (100 micrograms) of either GnRH preparation at the start of each test period in a 2-period crossover design. Serum samples were obtained prior to and at 12 times (10, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, and 1,440 minutes) after treatment and were assayed to determine circulating LH concentration. Significant difference between the 2 GnRH products was not found with respect to: mean concentration of LH in the blood during the 24 hours after treatment; maximal LH concentration; time from treatment to maximal LH concentration; and area under the LH concentration curve from time 0 through each of 7 times after treatment (0.5, 1, 1.5, 2, 4, 8, and 24 hours). These data confirm the bioequivalency of the 2 GnRH products.


Asunto(s)
Bovinos/metabolismo , Hormona Liberadora de Gonadotropina/farmacocinética , Animales , Estudios Cruzados , Femenino , Hormona Luteinizante/sangre , Progesterona/sangre , Equivalencia Terapéutica
18.
J Am Vet Med Assoc ; 211(10): 1280-4, 1997 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-9373366

RESUMEN

OBJECTIVE: To evaluate the effects of treatment at parturition with dinoprost tromethamine, fenprostalene, or oxytocin on postpartum disease and reproductive performance during the subsequent breeding season in dairy cows. DESIGN: Prospective study. ANIMALS: 1,400 Holstein cows from 5 commercial dairies. PROCEDURE: Cows were assigned within 2 hours after calving to serve as untreated control cows or to be treated with 1 mg of fenprostalene, SC; 25 mg of dinoprost tromethamine, IM; or 20 IU of oxytocin, IM. Cows were confined to treatment pens and monitored daily until fetal membranes were expelled. Cows with retained fetal membranes (RFM) were treated according to existing treatment protocols for the dairy, with the provision that intrauterine infusions were not allowed. All other disease conditions were recorded, and appropriate treatment was administered. Postpartum reproductive examinations were performed 28 to 56 days after parturition Breeding records were maintained for all cows until pregnancy was confirmed or the cow was removed from the herd. RESULTS: Fetal membranes were retained in 12.1% of all cows, and this outcome was unaffected by treatment. Compared with cows without RFM, cows with RFM had longer intervals to first insemination (76.4 vs 82.0 days), reduced first insemination conception rates (46.8 vs 28.0%), and increased number of days not pregnant (103.2 vs 127.4 days). Farm, as a variable, significantly affected development of RFM and postpartum disease conditions as well as reproductive performance during the subsequent breeding season. Fetal membranes were retained in 12.4, 15.2, 8.7, 6.3, and 16.9% of cows on farms 1, 2, 3, 4, and 5, respectively. Mean days to first insemination varied from 64.5 days (farm 3) to 91.5 days (farm 1). Mean number of days not pregnant varied from 94.8 days (farm 3) to 15.9 days (farm 4). CLINICAL IMPLICATIONS: Administration of prostaglandins or oxytocin at the time of calving does not reduce the incidence of RFM or improve reproductive performance. Farm management practices have the greatest impact on dairy cow performance.


Asunto(s)
Enfermedades de los Bovinos/prevención & control , Dinoprost/uso terapéutico , Trabajo de Parto/efectos de los fármacos , Oxitócicos/uso terapéutico , Oxitocina/uso terapéutico , Retención de la Placenta/veterinaria , Abortivos no Esteroideos/uso terapéutico , Animales , Cruzamiento , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/fisiopatología , Femenino , Incidencia , Trabajo de Parto/fisiología , Retención de la Placenta/fisiopatología , Retención de la Placenta/prevención & control , Embarazo , Estudios Prospectivos , Prostaglandinas F Sintéticas/uso terapéutico , Análisis de Regresión , Reproducción/efectos de los fármacos , Reproducción/fisiología , Factores de Tiempo
19.
J Am Vet Med Assoc ; 207(2): 214-6, 1995 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-7601719

RESUMEN

Cloprostenol was administered IV or IM to diestrous dairy cows to study luteolysis and synchrony of estrus and ovulation. In Study 1, 28 Holstein cows were assigned to receive injections of cloprostenol, IV or IM, on day 8 or 10 of the estrous cycle. Differences in cloprostenol-induced luteolysis or interval to estrus, were not detected. Ultrasonography revealed that 2 cows treated IV on day 8, 1 cow treated IM on day 8, and 2 cows treated IV on day 10 did not ovulate despite evidence of an apparently normal estrus. In Study 2, 20 Holstein cows were assigned to receive cloprostenol injections, IV or IM, on day 10 of the estrous cycle. Interval to estrus was not affected by route of administration. Analysis of these data indicated that cloprostenol given IV did not alter luteolysis or improve synchrony of estrus and ovulation when compared with cloprostenol given IM.


Asunto(s)
Bovinos/fisiología , Cloprostenol/administración & dosificación , Diestro/efectos de los fármacos , Sincronización del Estro/efectos de los fármacos , Animales , Cloprostenol/farmacología , Femenino , Inyecciones Intramusculares/veterinaria , Inyecciones Intravenosas/veterinaria , Luteólisis/efectos de los fármacos , Progesterona/sangre , Distribución Aleatoria
20.
J Am Vet Med Assoc ; 207(12): 1612-5, 1995 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-7493902

RESUMEN

Dairy cows (n = 207) that had retained fetal membranes for more than 8 hours after parturition were randomly assigned to 1 of 4 treatment groups (group 1, daily intrauterine infusion of oxytetracycline; group 2, daily intrauterine infusion of oxytetracycline and a single SC injection of fenprostalene; group 3, a single SC injection of fenprostalene; and group 4, untreated controls). Cows were monitored daily. Subsequent disease conditions were recorded, and appropriate treatments were initiated. Interval from parturition to expulsion of fetal membranes was unaffected by treatment regimen. The frequency of cows with high rectal temperatures (> or = 39.5 C) was significantly (P < 0.05) less in cows treated with oxytetracycline infusions; however, the frequency of displaced abomasum, ketosis, and mastitis was unaffected by treatment method. Treatment method appeared to influence the development of postpartum uterine pathologic conditions. Treatment with oxytetracycline and fenprostalene (group 2) increased (P < 0.05) the frequency of pyometra. Treatment with fenprostalene (groups 2 and 3) decreased the number of cows with a palpable uterine lumen detectable during per rectal palpation at 28 to 42 days after parturition. Reproductive efficiency, as determined on the basis of the interval from parturition to conception, was unaffected by treatment protocol.


Asunto(s)
Abortivos no Esteroideos/uso terapéutico , Antibacterianos/uso terapéutico , Enfermedades de los Bovinos/tratamiento farmacológico , Oxitetraciclina/uso terapéutico , Retención de la Placenta/veterinaria , Prostaglandinas F Sintéticas/uso terapéutico , Abortivos no Esteroideos/administración & dosificación , Animales , Antibacterianos/administración & dosificación , Bovinos , Quimioterapia Combinada , Femenino , Infusiones Parenterales/veterinaria , Inyecciones Subcutáneas/veterinaria , Oxitetraciclina/administración & dosificación , Retención de la Placenta/tratamiento farmacológico , Embarazo , Prostaglandinas F Sintéticas/administración & dosificación , Útero
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