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1.
BMC Vet Res ; 12(1): 268, 2016 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-27894292

RESUMEN

BACKGROUND: Respiratory problems are common in horses, and are often diagnosed as a cause of poor athletic performance. Reliable, accurate and sensitive spirometric tests of airway function in resting horses would assist with the diagnosis of limitations to breathing and facilitate investigations of the effects of various treatments on breathing capacity. The evaluation of respiratory function in horses is challenging and suitable procedures are not widely available to equine practitioners. The determination of relative flow or flow-time measures is used in paediatric patients where compliance may limit conventional pulmonary function techniques. The aim of the current study was to characterise absolute and relative indices of respiratory function in healthy horses during eupnoea (tidal breathing) and carbon dioxide (CO2)-induced hyperpnoea (rebreathing) using a modified mask pneumotrachographic technique well suited to equine practice, and to evaluate the reliability of this technique over three consecutive days. Coefficients of variation, intra-class correlations, mean differences and 95% confidence intervals across all days of testing were established for each parameter. RESULTS: The technique provided absolute measures of respiratory function (respiratory rate, tidal volume, peak inspiratory and expiratory flows, time to peak flow) consistent with previous studies and there was no significant effect of day on any measure of respiratory function. Variability of measurements was decreased during hyperpnea caused by rebreathing CO2, but a number of relative flow-time variables demonstrated good agreement during eupnoeic respiration. CONCLUSIONS: The technique was well tolerated by horses and study findings suggest the technique is suitable for evaluation of respiratory function in horses. The use of relative flow-time variables provided reproducible (consistent) results, suggesting the technique may be of use for repeated measures studies in horses during tidal breathing or rebreathing.


Asunto(s)
Caballos/fisiología , Pruebas de Función Respiratoria/veterinaria , Espirometría/veterinaria , Animales , Femenino , Reproducibilidad de los Resultados
2.
Anaesthesia ; 71(5): 550-5, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26948476

RESUMEN

This study sought to identify changes in hepatic flood flow and cardiac output during prone positioning on surgical bolsters in awake volunteers, and was prompted by a local incident of significant hepatic dysfunction following surgery in the prone position. Cardiac output was determined using the non-invasive Peñáz technique, and plasma disappearance rate of indocyanine green (ICG-PDR) was measured as a surrogate maker for hepatic blood flow along with serum hepatic enzyme assays. Measurements were made after one hour in supine, prone and returned supine positions. Ten volunteers completed the study. There were significant changes in the disappearance rate of indocyanine green, which decreased this from mean (SD) 31.1 (9.70) supine to 19.6 (4.37)%.min prone, respectively (p = 0.02), increasing on return to the supine position to 24.6 (5.54)%.min (p = 0.019). Cardiac output was also significantly reduced when changing from the supine to the prone position, from mean (SD) 4.7 (1.0 to 3.5 (1.1) (l.min(-1) ), respectively (p = 0.002). We demonstrated an acute and reversible change in both hepatocellular function and cardiac output associated with the prone position.


Asunto(s)
Circulación Hepática/fisiología , Posición Prona/fisiología , Arginasa/sangre , Presión Sanguínea/fisiología , Gasto Cardíaco/fisiología , Colorantes , Femenino , Voluntarios Sanos , Frecuencia Cardíaca/fisiología , Humanos , Verde de Indocianina , Hígado/enzimología , Pruebas de Función Hepática , Masculino , Posicionamiento del Paciente , Posición Supina/fisiología , Adulto Joven
3.
Science ; 218(4576): 996-1003, 1982 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-17790588

RESUMEN

The shuttle imaging radar (SIR-A) acquired images of a variety of the earth's geologic areas covering about 10 million square kilometers. Structural and geomorphic features such as faults, folds, outcrops, and dunes are clearly visible in both tropical and arid regions. The combination of SIR-A and Seasat images provides additional information about the surface physical properties: topography and roughness. Ocean features were also observed, including large internal waves in the Andaman Sea.

4.
Aust Vet J ; 86(11): 419-24, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18959528

RESUMEN

OBJECTIVE: To describe the impact of age, sex, and musculoskeletal (MS) injury on three preparation-level measures of performance: (i) the duration of preparation, (ii) time from the beginning of the preparation until the first start in a race or barrier trial, and (iii) time from the first start until the end of the preparation. METHODS: Daily training and injury data for 2- and 3-year old Thoroughbred racehorses were collected fortnightly from 14 trainers in NSW, Australia. Training data were aggregated into units referred to as 'preparations'. Univariate and multivariate analytical methods were used to examine the associations between the explanatory variables and each of the measures of performance. RESULTS: There were 1274 preparations recorded in 451 horses. Younger horses had a shorter interval from the first start in a race or barrier trial to the end of the preparation. MS injury was not conditionally associated with any of the outcomes. CONCLUSION: MS injuries in young racehorses have limited impact on long-term performance, although care must be taken in interpreting the results because they could be confounded by variables not considered in this analysis. This study also begins to unravel the complicated relationship between age and previous exposure to training, with results supporting the hypothesis that the intensity of training increases with increasing age.


Asunto(s)
Traumatismos en Atletas/veterinaria , Enfermedades de los Caballos/epidemiología , Caballos/fisiología , Enfermedades Musculoesqueléticas/veterinaria , Sistema Musculoesquelético/lesiones , Condicionamiento Físico Animal/métodos , Factores de Edad , Animales , Traumatismos en Atletas/epidemiología , Traumatismos en Atletas/etiología , Traumatismos en Atletas/prevención & control , Femenino , Enfermedades de los Caballos/etiología , Enfermedades de los Caballos/prevención & control , Masculino , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Musculoesqueléticas/etiología , Enfermedades Musculoesqueléticas/prevención & control , Factores Sexuales , Deportes
5.
Aust Vet J ; 86(12): 473-80, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19076769

RESUMEN

OBJECTIVE: To describe the incidence rate of musculoskeletal (MS) injuries and investigate the factors that influence recovery from MS injury in young Thoroughbred horses in Australia. METHODS: Training and injury data were collected at fortnightly intervals from 14 trainers in New South Wales. Incidence rates were calculated for initial injuries stratified by age-class and sex. Survival analysis methods were used to investigate the time to recovery after the first MS injury (measured as a start in a race or barrier trial). RESULTS: For the 248 racehorses enrolled, there were 428 injuries recorded; 2-year-olds were 2.99-fold more likely than 3-year-olds to sustain an MS injury. The cumulative percentage of horses that had recovered within 6 months was 55%. The time to recovery was longest in horses whose fast gallop speed prior to injury was < 890 m/min. CONCLUSION: This study supports the finding that shin soreness is the most common MS injury in young Australian Thoroughbreds. There was an increased rate of MS injury in 2-year-olds compared with 3-year-olds. However, it was impossible to determine if the increased risk in 2-year-olds was related to age, the start of training or a combination of both. The study also found that horses performing at higher exercise speeds prior to injury were more likely to recover. There was a significant effect of trainer, suggesting that other factors related to trainer may influence the time to the recovery. Additional research is required to understand the determinants of time to recovery.


Asunto(s)
Traumatismos en Atletas/veterinaria , Caballos/lesiones , Sistema Musculoesquelético/lesiones , Condicionamiento Físico Animal/efectos adversos , Factores de Edad , Animales , Traumatismos en Atletas/epidemiología , Traumatismos en Atletas/etiología , Traumatismos en Atletas/mortalidad , Femenino , Incidencia , Masculino , Nueva Gales del Sur/epidemiología , Factores de Riesgo , Factores Sexuales , Deportes , Análisis de Supervivencia , Factores de Tiempo
6.
Equine Vet J ; 50(1): 91-97, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28627036

RESUMEN

BACKGROUND: The need for a horse to be ridden while wearing a measurement device that allows unrestricted ventilation and gas exchange has hampered accurate measurement of its maximal oxygen consumption (V̇O2 max) under field conditions. OBJECTIVES: Design and validate a facemask with the potential to measure V̇O2 max accurately in the field. STUDY DESIGN: Experiment with 6 × 6 Latin square design. METHODS: Two variations of a mask and associated electronic control module (ECM) were designed to enable breath-by-breath measurement of airflows through two 7.8 cm diameter pneumotachometers located 7.5 cm in front of each narus. The ECM was comprised of an analogue-to-digital converter and a lithium-ion battery that provided power and signal filtering to the pneumotachometers and an oxygen sensing cell, and powered a pump connected to gas sampling ports between the nares and pneumotachometers. Airflow and oxygen content of inspired and expired gases were recorded through the ECM and electronically transferred to a notebook. V̇O2 was determined from these recordings using a customised software program. Mask B encased the lower jaw. Mask R left the jaw free so the horse could wear a bit if ridden. V̇O2 max and arterial blood gases were measured in 6 horses during multiple treadmill tests. Each mask was worn twice and results compared to those from an established open flow-through system (O) by ANOVA-RM (P<0.05). System utility was evaluated using the intraclass correlation coefficient of 4 independent raters. RESULTS: Blood gases and V̇O2 max (151.9±7.0 [mean±s.d.; O], 151.5±9.6 [B], 149.5±7.5 [R] ml/[kg.min]) were not different between masks. V̇O2 max measures were reproducible for each mask. Intraclass correlation coefficient between raters = 0.99. MAIN LIMITATIONS: Some rebreathing of expired air from mask dead space. CONCLUSION: Masks capable of measuring V̇O2 max during treadmill exercise were developed, tested and found to be accurate. Mask R has potential application to measurement of V̇O2 max under field conditions.


Asunto(s)
Caballos/fisiología , Máscaras , Condicionamiento Físico Animal/fisiología , Intercambio Gaseoso Pulmonar/fisiología , Animales , Análisis de los Gases de la Sangre/veterinaria , Dióxido de Carbono , Femenino , Masculino , Oxígeno , Fenómenos Fisiológicos Respiratorios
7.
Aliment Pharmacol Ther ; 25(10): 1163-74, 2007 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-17451562

RESUMEN

BACKGROUND: Whether antidepressants prevent depression during interferon-alpha/ribavirin treatment for hepatitis C virus infection has yet to be established. AIM: To investigate the use of paroxetine in a prospective, double-blind, placebo-controlled study for this indication. METHODS: Sixty-one hepatitis C virus-infected patients were randomly assigned to the antidepressant, paroxetine (n = 28), or placebo (n = 33), begun 2 weeks before and continued for 24 weeks during interferon-alpha/ribavirin treatment. Primary endpoints included development of major depression and severity of depressive symptoms measured by the Montgomery Asberg Depression Rating Scale (MADRS). RESULTS: Rates of major depression during the study were low (17%) and did not differ between groups. Nevertheless, using published MADRS cut-off scores, the percent of subjects who met criteria for mild, moderate or severe depression during interferon-alpha/ribavirin therapy was significantly lower in paroxetine- vs. placebo-treated subjects (P = 0.02, Fisher's exact test). Assignment to paroxetine was also associated with significantly reduced depressive symptom severity. This effect was largely accounted for by participants with depression scores above the median (MADRS > 3) at baseline in whom paroxetine was associated with a maximal reduction in MADRS scores of 10.3 (95% CI: 2.1-18.5) compared with placebo at 20 weeks (P < 0.01). Study limitations included a small sample size and high drop-out rate. CONCLUSION: This double-blind, placebo-controlled trial provides preliminary data in support of antidepressant pre-treatment in hepatitis C virus patients with elevated depressive symptoms at baseline.


Asunto(s)
Antivirales/uso terapéutico , Trastorno Depresivo Mayor/prevención & control , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Ribavirina/uso terapéutico , Adolescente , Adulto , Anciano , Antivirales/farmacocinética , Trastorno Depresivo Mayor/virología , Método Doble Ciego , Femenino , Hepatitis C Crónica/psicología , Humanos , Interferón-alfa/farmacocinética , Masculino , Persona de Mediana Edad , Paroxetina/uso terapéutico , Ribavirina/farmacocinética
8.
Equine Vet J ; 39(4): 373-83, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17722733

RESUMEN

This review addresses the physiology of performance horses in the context of functional tests aimed at assisting clinicians in the search for explanations of the individual's limitations, actual or perceived as below expectation. The intention is to assist clinicians who are faced frequently by owners or trainers seeking explanations for poor performance; and for research workers as a basis on which to proceed in their search for new methodologies, particularly those that can be applied in the field as for treadmill exercise. The review sets out fundamental physiological pathways, the entailment of which may represent a limiting factor to performance, while taking into account the individual's status, including anamnesis and the possibility of actual disease being present. Tests that assess the possible roles of several body systems, as causes of limited performance, are discussed. These systems include pulmonary, cardiovascular and neuromuscular systems. The evaluation of anaerobic and aerobic energy pathways is also discussed. Emphasis is given to the assessment of pulmonary ventilation by techniques such as spirometry and ergospirometry. These techniques are considered to be of particular potential for further development.


Asunto(s)
Estado de Salud , Enfermedades de los Caballos/fisiopatología , Caballos/fisiología , Consumo de Oxígeno/fisiología , Condicionamiento Físico Animal/fisiología , Animales , Prueba de Esfuerzo/veterinaria , Enfermedades de los Caballos/diagnóstico , Cojera Animal/diagnóstico , Cojera Animal/fisiopatología , Respiración
9.
Prev Vet Med ; 74(1): 36-43, 2006 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-16481055

RESUMEN

Musculoskeletal injuries (MSI) in racehorses have been identified as the most common cause of lost training days and weeks spent resting at pasture. Several training-, track- and horse-related risk factors have been identified. However, there is no clear understanding of the inter-relationship between these factors. The aim of this longitudinal cohort study was to investigate risk factors for MSI in 2-year-old Thoroughbred racehorses. Australian Thoroughbred trainers were convenience sampled and enrolled in a 27-month longitudinal cohort study. The study population consisted of all 2-year-old Thoroughbred racehorses trained by a participating trainer. Horses were followed from the time of enrollment until the completion of the study or until they were lost to follow-up. Trainers were visited at approximately 14-day intervals to collect training and injury data. Training days were categorised as fast days if the maximum speed during training exceeded 800 m/min. For each horse, the first training period that included one or more fast days was analysed. A multiple logistic regression model was used to determine those horse- and training-related variables that were associated with MSI. Data from 274 horses trained by 14 trainers at five racetracks were analysed. Forty percent of the horses sustained a MSI during their first fast preparation. The average distance trained at speeds >or=800 m/min and the percentages of fast days from the first fast day until the end of the preparation were the only variables associated with MSI. After accounting for these variables there were still significant differences between trainers. This suggests that there are other training-related variables such as the rate of increase in distance trained at speeds >or=800 m/min that may be risk factors for MSI. In addition, other factors such as the level of veterinary involvement and the training centre/racetrack may be risk factors for MSI. More analysis using multi-level modelling is required to determine the relationship between trainer- and track-related risk factors.


Asunto(s)
Traumatismos en Atletas/veterinaria , Caballos/lesiones , Sistema Musculoesquelético/lesiones , Condicionamiento Físico Animal/efectos adversos , Deportes , Animales , Traumatismos en Atletas/epidemiología , Traumatismos en Atletas/etiología , Estudios de Cohortes , Femenino , Modelos Logísticos , Estudios Longitudinales , Masculino , Factores de Riesgo
10.
J Natl Cancer Inst ; 72(6): 1357-63, 1984 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-6233443

RESUMEN

New Zealand Black ( NBR ) rats that are innately immune to challenge with a syngeneic 3-methylcholanthrene [(MCA) CAS: 56-49-5]-induced fibrosarcoma have spleen cells that produce helper effects for in vitro lymphoproliferative responses in the presence of individual MCA-induced fibrosarcoma cells. Spleen cells from MCA-induced fibrosarcoma progressor rats (which lack innate tumor immunity) do not produce demonstrable helper activity. Supernatants from 48-hour cocultures of spleen cells from tumor-immune (TI) rats and syngeneic MCA-induced fibrosarcoma cells replaced the spleen cell helper activity. Comparable spleen cell supernatants from tumor progressor rats or unchallenged rats (controls) as well as supernatants from MCA-induced fibrosarcoma cells cultured alone did not produce any helper factor activity. Supernatants from TI rat spleen cells following inoculation with MCA-induced fibrosarcoma cells did not affect lymphoproliferative responses of NBR spleen cells induced by concanavalin A or alloantigens. The supernatants also did not contain detectable interleukin 2 activity as determined with the use of the thymocyte costimulator assay. These data indicate that the production of soluble helper factors by TI rat spleen cells may be involved in the augmentation of a protective host antitumor response.


Asunto(s)
Fibrosarcoma/inmunología , Linfocinas/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Concanavalina A/inmunología , Fibrosarcoma/inducido químicamente , Prueba de Cultivo Mixto de Linfocitos , Metilcolantreno , Trasplante de Neoplasias , Ratas , Ratas Endogámicas BUF , Ratas Endogámicas , Solubilidad , Bazo/inmunología , Trasplante Isogénico
11.
J Natl Cancer Inst ; 69(1): 53-8, 1982 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-6212710

RESUMEN

Young New Zealand Black rats (less than 35 wk old) developed progressively growing tumors when given injections of cells from a syngeneic 3-methylcholanthrene (MCA)-induced fibrosarcoma. Spontaneous tumor regression occurred in animals more than 10 months of age. Compared to the responses of spleen cells from age-matched controls, spleen cells from rats in which tumor progression was present progressor rats) showed decreased proliferative responses to concanavalin (Con A), phytohemagglutinin (PHA), and syngeneic MCA tumor cells. Spleen cells from rats in which the tumors had regressed (regressor rats), however, produced significant increases in proliferative responses when compared with the responses of spleen cells from age-matched controls and from progressor rats. Cell-mixing experiments implicated the presence of two spleen suppressor cell populations in progressor rats, one of which was not present in regressor rats. The unique suppressor cell found in progressor rats appeared to be specific for tumor cell-induced proliferative responses. Spleen cells from both progressor and regressor rats produced similar suppressive effects in the PHA and Con A responses of normal cells.


Asunto(s)
Fibrosarcoma/metabolismo , Bazo/patología , Linfocitos T Reguladores/análisis , Animales , División Celular , Concanavalina A/farmacología , Fibrosarcoma/patología , Metilcolantreno , Regresión Neoplásica Espontánea , Fitohemaglutininas/farmacología , Ratas , Ratas Endogámicas , Bazo/efectos de los fármacos
12.
Cancer Res ; 53(9): 2133-9, 1993 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-8481916

RESUMEN

A 2-h exposure of JB1 rat hepatoma cells in late log phase of growth to 50 microM cis-diamminedichloroplatinum (II) (cisplatin) resulted in the asynchronous detachment of cells from the monolayer over 4 days. Detached but not monolayer cells exhibited condensed chromatin and DNA fragmentation, which is indicative of endonuclease activation, the hallmarks of apoptosis in epithelial cells. The number of cisplatin-treated cells identified as apoptotic at any one time was never > 1% of the total cell number present on addition of drug. Two days after drug addition there was a decrease from 85% to 29% cells in G1 phase of the cell cycle, cells in S phase increased from 9% to 18%, and cells in G2/M phase increased from 6% to 51% with respect to untreated cells. Previous studies by Eastman and colleagues demonstrated that cisplatin-induced apoptosis of Chinese hamster ovary cells occurred in the G2 phase of the cell cycle [A. Eastman, Cancer Cells (Cold Spring Harbor), 2: 275-280, 1990]. Continuous exposure of JB1 cells to cycloheximide (1 microM) during and after exposure to cisplatin prevented both drug-induced changes in cell cycle distribution and the engagement of apoptosis. Freshly isolated immature rat thymocytes are known to be exquisitely sensitive to the induction of apoptosis by multiple stimuli including dexamethasone, etoposide, and irradiation. However, no significant increase in the amount of apoptosis above control levels was observed up to 36 h after a 2-h exposure to 50 microM cisplatin. JB1 cells have a doubling time of 24 h, whereas > 90% of immature rat thymocytes are noncycling. The data presented here provide indirect evidence that initiation of cisplatin-induced apoptosis may need to be coupled to a cell cycle-mediated event.


Asunto(s)
Apoptosis/efectos de los fármacos , Cisplatino/farmacología , Neoplasias Hepáticas Experimentales/patología , Timo/efectos de los fármacos , Animales , Ciclo Celular , Supervivencia Celular/efectos de los fármacos , Cromatina/ultraestructura , Cicloheximida/farmacología , Daño del ADN , Relación Dosis-Respuesta a Droga , Femenino , Neoplasias Hepáticas Experimentales/tratamiento farmacológico , Masculino , Ratas , Ratas Sprague-Dawley , Timo/citología , Factores de Tiempo
13.
Cancer Res ; 54(6): 1596-603, 1994 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-8137265

RESUMEN

Immature rat thymocytes readily undergo apoptosis following exposure to many different stimuli, including agents which cause DNA damage, such as the topoisomerase II inhibitor etoposide and irradiation. We have shown previously that cells isolated from the immature rat thymus are resistant to the induction of apoptosis by the DNA-damaging agent cis-diamminedichloroplatinum(II) (cisplatin) (D. L. Evans and C. Dive, Cancer Res., 53:2133-2139, 1993). More than 85% of these thymocytes are quiescent. Here, we demonstrate that following purification of the minority subpopulation of thymocytes that are proliferating, a 2-h exposure to 50 microM cisplatin resulted in rapid apoptosis with 66% apoptotic cells by 12 h. In contrast, purified, nonproliferating thymocytes treated with cisplatin exhibited control levels of apoptosis at 12 h. Both proliferating and nonproliferating thymocytes rapidly underwent apoptosis following continuous exposure to methylprednisolone (10 microM) and etoposide (10 microM). The discrepancy in the levels of apoptosis seen in proliferating and quiescent thymocytes in response to cisplatin could not be attributed to changes in total cellular levels of cisplatin or to the number of DNA-platinum adducts which were determined, respectively, by atomic absorption spectrometry and competitive enzyme-linked immunoadsorbent assay. These results imply that in contrast to engagement of thymocyte apoptosis by methylprednisolone and etoposide, where apoptosis was proliferation independent, cisplatin-induced apoptosis depends on the presence of cells in S and G2-M phases of the cell cycle. Moreover, comparison of etoposide and cisplatin responses in thymocytes suggests that DNA damage per se may not be sufficient to induce apoptosis and that the type of DNA damage is important in this regard.


Asunto(s)
Apoptosis/efectos de los fármacos , Cisplatino/metabolismo , Cisplatino/farmacología , Cisplatino/farmacocinética , Aductos de ADN , Daño del ADN , ADN/metabolismo , Timo/citología , Timo/efectos de los fármacos , Animales , División Celular/efectos de los fármacos , División Celular/fisiología , Fraccionamiento Celular , Ensayo de Inmunoadsorción Enzimática , Etopósido/farmacología , Femenino , Fase G2/efectos de los fármacos , Fase G2/fisiología , Masculino , Metilprednisolona/farmacología , Mitosis/efectos de los fármacos , Mitosis/fisiología , Platino (Metal)/metabolismo , Ratas , Ratas Sprague-Dawley , Fase S/efectos de los fármacos , Fase S/fisiología , Timo/metabolismo
14.
Cancer Res ; 55(13): 2883-91, 1995 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-7540951

RESUMEN

To better understand how the E2F1 transcription factor contributes to the process of cell proliferation, NIH-3T3 cell lines were generated that constitutively express either the wild-type E2F1 protein or an amino terminal deletion mutant, termed E2F1d87. Proliferating E2F1d87-expressing cells exhibit a significant lengthening of S phase relative to control and E2F1 cell lines and are hypersensitive to the cytotoxic effects of the S phase-specific antitumor drug camptothecin. This sensitivity is associated with an increase in drug-induced p53 and WAF1 levels. The E2F1 and E2F1d87 cell lines are both able to initiate, but not complete, S phase under conditions of serum starvation. However, quantitation of DNA synthesis, during culture in serum-deprived media, indicates that the E2F1d87 cell line synthesizes more DNA/cell as compared to the E2F1 cell line. Consistent with this relative increase in DNA synthesis, the E2F1d87 cell line undergoes camptothecin-induced apoptosis when cultured under conditions of serum starvation, while the control and E2F1 cell lines are unaffected by drug treatment under the same conditions. Thus, the sensitivity of the E2F1d87 cell line to camptothecin is not dependent on cell proliferation. The data presented here suggest that cell cycle parameters can be manipulated in order to enhance sensitivity of a cell to the toxic effects of specific chemotherapeutic agents.


Asunto(s)
Proteínas Portadoras , Proteínas de Ciclo Celular , Ciclo Celular , Proteínas de Unión al ADN , Fase S , Factores de Transcripción/fisiología , Células 3T3 , Animales , Afidicolina/farmacología , Apoptosis/efectos de los fármacos , Bleomicina/toxicidad , Camptotecina/toxicidad , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , ADN/biosíntesis , ADN-Topoisomerasas de Tipo I/metabolismo , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Etopósido/toxicidad , Ratones , Proteína 1 de Unión a Retinoblastoma , Eliminación de Secuencia , Factor de Transcripción DP1 , Proteína p53 Supresora de Tumor/metabolismo
15.
BJA Educ ; 21(9): 329-335, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34447579
16.
Biochim Biophys Acta ; 1133(3): 275-85, 1992 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-1737061

RESUMEN

Necrosis and apoptosis are two distinct modes of cell death which differ in morphology, mechanism and incidence. Membrane disruptants, respiratory poisons and hypoxia cause ATP depletion, metabolic collapse, cell swelling and rupture leading to inflammation. These are typical features of necrosis. Apoptosis plays a crucial role in embryogenesis and development and is also prevalent in tumours. It is characterised by cell shrinkage, chromatin condensation and systematic DNA cleavage. Apoptotic cells are rapidly engulfed by phagocytes, thus preventing inflammatory reaction to degradative cell contents. In vivo, apoptosis is almost impossible to quantify due to problems of heterogeneity and the short half-life of an apoptotic cell. In vitro, mechanistic studies are further complicated by a late phase of apoptosis where the cell membrane becomes permeable to vital dyes and which occurs in the absence of phagocytes. Here we describe a novel and rapid multiparameter flow cytometric assay which discriminates and quantifies viable, apoptotic and necrotic cells via measurement of forward and side light scatter (proportional to cell diameter and internal granularity, respectively) and the DNA-binding fluorophores Hoechst 33342 and propidium. It is anticipated that mechanistic studies of apoptosis in a variety of cell types will greatly benefit from this mode of analysis.


Asunto(s)
Muerte Celular , Citometría de Flujo/métodos , Necrosis , Animales , Bencimidazoles , Linfoma de Burkitt/patología , Células Cultivadas , Colorantes Fluorescentes , Inmunoglobulina G/metabolismo , Hígado/citología , Metilprednisolona/farmacología , Ratas , Dispersión de Radiación , Timo/citología , Timo/efectos de los fármacos
17.
Arch Gen Psychiatry ; 55(7): 580-92, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9672048

RESUMEN

This article reviews the burgeoning literature on the relationship of mood disorders and heart disease. Major depression and depressive symptoms, although commonly encountered in medical populations, are frequently underdiagnosed and undertreated in patients with cardiovascular disease (CVD). This is of particular importance because several studies have shown depression and its associated symptoms to be a major risk factor for both the development of CVD and death after an index myocardial infarction. This review of the extant literature is derived from MEDLINE searches (1966-1997) using the search terms "major depression," "psychiatry," "cardiovascular disease," and "pathophysiology." Studies investigating pathophysiological alterations related to CVD in depressed patients are reviewed. The few studies on treatment of depression in patients with CVD are also described. Treatment of depression in patients with CVD improves their dysphoria and other signs and symptoms of depression, improves quality of life, and perhaps even increases longevity. Recommendations for future research are proposed.


Asunto(s)
Enfermedades Cardiovasculares/epidemiología , Trastorno Depresivo/epidemiología , Adulto , Sistema Nervioso Autónomo/fisiología , Enfermedades Cardiovasculares/fisiopatología , Enfermedades Cardiovasculares/terapia , Comorbilidad , Citocinas/fisiología , Trastorno Depresivo/fisiopatología , Trastorno Depresivo/terapia , Femenino , Predicción , Humanos , Masculino , Infarto del Miocardio/epidemiología , Infarto del Miocardio/fisiopatología , Activación Plaquetaria/fisiología , Prevalencia , Psicoterapia , Psicotrópicos/uso terapéutico , Investigación/tendencias , Proyectos de Investigación/normas , Estrés Psicológico/fisiopatología
18.
Arch Gen Psychiatry ; 54(3): 279-85, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9075469

RESUMEN

BACKGROUND: This study examined how severe stress and depressive symptoms were related to changes in immune measures during a 2-year period in a sample of gay men with human immunodeficiency virus (HIV) infection. These analyses follow up our initial cross-sectional observations that severe stress was correlated with lower levels of natural killer (NK) cells and CD8+ T lymphocytes in these men. METHODS: Data were collected in North Carolina as part of an ongoing, longitudinal study, the Coping in Health and Illness Project. Sixty-six HIV-infected gay men, who were asymptomatic at baseline, were assessed systematically at 6-month intervals. RESULTS: Severe stress and depressive symptoms were independently related to decreases on immune measures from entry to 2-year follow-up, that is, declines in CD8+ T cells and CD56+ and CD16+ NK cell subsets. Subjects most likely to have decreases on these immune measures were those who scored above the median on both stress and depressive symptoms. CONCLUSIONS: Our findings are among the first prospective data showing that stress and depressive symptoms, especially when they occur jointly, are associated with decreased number of NK and CD8+ T lymphocytes in HIV-infected men. Since these immune cells may play a protective role in the progression of HIV infection, our data suggest that stress and depressive symptoms may have clinical implications for the course of this disease.


Asunto(s)
Trastorno Depresivo/epidemiología , Infecciones por VIH/inmunología , Homosexualidad Masculina , Acontecimientos que Cambian la Vida , Subgrupos Linfocitarios/inmunología , Adulto , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Comorbilidad , Trastorno Depresivo/inmunología , Citometría de Flujo , Infecciones por VIH/epidemiología , Humanos , Células Asesinas Naturales/inmunología , Recuento de Linfocitos , Masculino , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Índice de Severidad de la Enfermedad , Subgrupos de Linfocitos T/inmunología
19.
Arch Gen Psychiatry ; 49(5): 388-95, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1534002

RESUMEN

The effects of major depression on peripheral blood natural killer cell phenotypes and natural killer cell activity were studied by comparing depressed and normal control subjects. Depressed subjects exhibited (1) significant reductions in Leu-11 (CD16) natural killer effector cells and natural killer cell activity and (2) a dissociation of the normal positive correlation between the percentage of Leu-11 cells and natural killer cell activity. These findings suggest that alterations in the availability and the killing capacity of circulating Leu-11 natural killer cells appear to be responsible for depression-related reductions in natural killer cell activity. Moreover, men with major depression showed marked reductions in Leu-11 cells, natural killer cell activity, and Leu-7 (HNK-1) lymphocytes compared with normal control men. By contrast, depressed women did not differ significantly from normal control women on any of these three immune function measures. Severity of depression as assessed by Hamilton Rating Scale for Depression scores was not associated with natural killer cell activity or Leu-7 lymphocyte levels in either men or women with major depression. Hamilton Rating Scale for Depression severity ratings were, however, strongly inversely correlated with Leu-11 lymphocyte counts among men, but not women, with major depression. These data begin to elucidate the immunological mechanisms by which natural killer cell activity is altered in depression and suggest that some measures of immunity may be differentially affected in male and female subjects with the syndrome of major depression.


Asunto(s)
Trastorno Depresivo/inmunología , Células Asesinas Naturales/inmunología , Adolescente , Adulto , Antígenos de Diferenciación/inmunología , Citotoxicidad Inmunológica , Trastorno Depresivo/diagnóstico , Femenino , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Fenotipo , Receptores Fc/inmunología , Receptores de IgG , Índice de Severidad de la Enfermedad
20.
Cell Signal ; 11(4): 287-92, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10372806

RESUMEN

The antigen receptor (nonspecific cytotoxic cell receptor protein-1/NCCRP-1) on nonspecific cytotoxic cells (NCC) is a 32-kDa predicted Type III membrane protein. The N-terminal cytoplasmic portion of this receptor contains full length and truncated BOX-1 motifs. These motifs are also found on cytokine, erythropoietin and growth hormone receptors and provide docking sites for JAK kinases. In the present study, we investigated a relationship between NCCRP-1 and JAK2 kinase binding. A possible association with further downstream STAT activation was suggested. NCCRP-1 was phosphorylated on C-terminal domain serine residues. To examine the possibility that NCCRP-1 was associated with JAK kinase(s), NCC were purified and lysates were probed by Westen blotting (WB) for the presence of JAK2 kinase. Unlike their mammalian counterparts, NCC JAK2 kinase existed as a 90-95-kDa primary and a 35-40-kDa secondary breakdown product. Both mol wt. forms were significantly smaller than those reported for human JAK kinases. To determine if NCCRP-1 was physically associated with JAK2 kinase, chemical cross-linking experiments were conducted. NCC membrane preparations were treated with the chemical cross-linker DSS, solubilised and immunoprecipitated with anti-NCCRP-1 (e.g., 32 kDa) mab 5C6. WB analysis using anti-JAK2 mab and mab 5C6 demonstrated that the immunoprecipitate contained both the 32-kDa NCCRP-1 and 85-90-kDa JAK2 kinase. To examine further the possibility that STAT proteins may be associated with NCC/NCCRP-1 activation, NCC lysates were probed (WB) with various anti-STAT mabs. The strongest signal was produced by a 100-kDa STAT-6 protein. Lysates were negative for STAT-1, STAT-3 and STAT-5. These data indicate that the N-terminus of NCCRP-1 may initiate cytokine gene transcription by the JAK-STAT signalling pathway.


Asunto(s)
Células Asesinas Naturales/metabolismo , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas , Receptores de Antígenos/metabolismo , Transducción de Señal , Transactivadores/metabolismo , Animales , Bagres , Células Cultivadas , Activación Enzimática , Femenino , Janus Quinasa 2 , Células Asesinas Naturales/citología , Masculino , Fosfoserina/metabolismo , Factor de Transcripción STAT6
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