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1.
J Dairy Sci ; 102(7): 6555-6558, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31128868

RESUMEN

Precision dairy monitoring technologies have become increasingly popular for recording rumination and feeding behaviors in dairy cattle. The objective of this study was to validate the rumination and feeding time functions of the CowManager SensOor (Agis, Harmelen, the Netherlands) against visual observation in dairy heifers. The study took place over a 44-d period beginning June 1, 2016. Holstein heifers equipped with CowManager SensOor tags attached according to manufacturer specifications (n = 49) were split into 2 groups based on age, diet, and housing type. Group 1 heifers (n = 24) were calves (mean ± SD) 2.0 ± 2.7 mo in age, fed hay and calf starter, and housed on a straw-bedded pack. Group 2 heifers (n = 25) were 17.0 ± 1.3 mo in age, fed a TMR, confirmed pregnant, and housed in freestalls. Visual observation shifts occurred at 1500, 1700, 1900, and 2100 h. Each heifer was observed for 2 hour-long periods, with both observation periods occurring on the same day. Visual observations were collected using a synchronized watch, and "start" and "stop" times were recorded for each rumination and feeding event. For correlations, data from CowManager SensOor tags and observations were averaged, so a single 1-h observation was provided per animal, reducing the potential for confounding repeated measures being collected for each animal. Concordance correlations (CCC; epiR package; R Foundation for Statistical Computing, Vienna, Austria) and Pearson correlations (r; CORR procedure; SAS Institute Inc., Cary, NC) were used to calculate association between visual observations and technology-recorded behaviors. Visually observed rumination time was correlated with the CowManager SensOor (r = 0.63, CCC = 0.55). Visually observed feeding time was also correlated with the CowManager SensOor (r = 0.88, CCC = 0.72). The difference between technology-recorded data and visual observation was treated as the dependent variable in a mixed linear model (MIXED procedure of SAS). Time of day, age in months, and group were treated as fixed effects. Individual heifers were treated as random and repeated effects. The effects of time of day, age, and group on rumination and feeding times were not significant. The CowManager SensOor was more effective at recording feeding behavior than rumination behavior in dairy heifers. The CowManager SensOor can be used to provide relatively accurate measures of feeding time in heifers, but its rumination time function should be used with caution.


Asunto(s)
Bovinos/fisiología , Conducta Alimentaria , Rumen/metabolismo , Alimentación Animal/análisis , Animales , Femenino
2.
J Dairy Sci ; 102(1): 320-333, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30343910

RESUMEN

The use of coproducts as an alternative feed source is a common practice when formulating dairy rations. A study using 12 multiparous (79 ± 16 d in milk; mean ± standard deviation) lactating Jersey cows was conducted over 5 mo to evaluate the effects of dried distillers grains with solubles (DDGS) or canola meal on milk and gas production. A replicated 4 × 4 Latin square design was used to compare 4 dietary treatments. Treatments comprised a control (CON) containing no coproducts, a treatment diet containing 10% (dry matter basis) low-fat DDGS (LFDG), a treatment diet containing 10% high-fat DDGS (HFDG), and a 10% canola meal (CM) treatment. The crude fat content of the LFDG, HFDG, and CM treatments was 6.05 ± 0.379, 10.0 ± 0.134, and 3.46 ± 0.085%, respectively. Coproducts were included in partial replacement for corn and soybean meal. Indirect headbox-style calorimeters were used to estimate heat production. Dry matter intake and milk yield were similar between all treatments, averaging 17.4 ± 0.56 kg/d and 24.0 ± 0.80 kg, respectively. Milk urea N was affected by treatment and was highest in CON (20.6 mg/dL; 18.0, 19.9, and 18.1 ± 0.62 mg/dL in LFDG, CM, and HFDG, respectively). Heat production per unit of metabolic body weight tended to be affected by treatment and was lowest for CON, and diets containing coproducts were not different (192, 200, 215, and 204 ± 5.91 kcal/kg of metabolic body weight for CON, LFDG, CM, and HFDG, respectively). The concentration of metabolizable energy was affected by dietary treatment; specifically, HFDG did not differ from CON but was greater than LFDG and CM (2.58, 2.46, 2.29, and 2.27 ± 0.09 Mcal/kg for HFDG, CON, LFDG, and CM, respectively). The concentration of net energy balance (milk plus tissue) tended to be affected by dietary treatment; HFDG did not differ from either CON or LFDG, but it was higher than CM (1.38, 1.36, 1.14, and 1.06 ± 0.11 Mcal/kg for HFDG, CON, LFDG, and CM, respectively). Results of this study indicate that milk production and dry matter intake were not affected by feeding common coproducts and that differences may result in whole-animal energy use; fat content of DDGS is a major factor affecting this.


Asunto(s)
Alimentación Animal/análisis , Bovinos/metabolismo , Leche/metabolismo , Animales , Peso Corporal , Brassica napus/química , Brassica napus/metabolismo , Calorimetría Indirecta/métodos , Bovinos/crecimiento & desarrollo , Dieta/veterinaria , Femenino , Lactancia , Leche/química , Glycine max/química , Glycine max/metabolismo , Zea mays/química , Zea mays/metabolismo
3.
BMC Oral Health ; 19(1): 2, 2019 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-30611255

RESUMEN

BACKGROUND: The oral health status of pregnant women in low-resource communities such as Nepal has not been well characterized. This sub-population is also of specific interest given associations between poor oral health and adverse pregnancy outcomes previously documented in other settings. We explored relationships between gingivitis and risk factors among pregnant women in rural Nepal. METHODS: The design was a community-based, cross-sectional study in a sub-area of Sarlahi District, Nepal. Pregnant women < 26 weeks gestation underwent clinical periodontal exams conducted by community-based oral health workers. Exams included a full mouth assessment measuring bleeding on probing (BOP), probing depth (PD) (six sites per tooth), and gingival recession, the distance from the cemento-enamel junction to the free gingival margin (two direct sites per tooth). Data on participant risk factors were collected through household surveys, including demographic characteristics, oral health behaviors, care seeking, and health attitudes. Multivariable logistic regression modeling was used to assess relationships between gingivitis and risk factors. RESULTS: We enrolled 1452 participants, of which 40% (n = 582) had signs of clinical gingivitis and 60% (n = 870) clinical health. Average participant age was 23. Most participants (88%) had never received oral health care. Participants averaged 10% of sites with BOP with most (79%) having ≥1 site with BOP. Nine percent of participants had ≥1 site with PD ≥4 mm, although very few participants (0.7%) had sites with PD ≥5 mm. Few participants (13%) had any recession (≥1 mm). In the final adjusted model, odds of gingivitis increased by 3% for each year of age (aOR 1.03, 95% CI 1.00, 1.06) and were higher for women of short maternal stature (< 150 cm) (aOR 1.43, 95% CI: 1.14, 1.79) and among women reporting cost to be a barrier to seeking dental care (aOR 2.13, 95% CI: 1.09, 4.15). CONCLUSIONS: Gingivitis was common and associated with age, maternal stature, self-reported high cost of dental care, and other risk factors among pregnant women in rural Nepal. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01177111 (Nepal Oil Massage Study) and NCT02788786 (Pilot Trial).


Asunto(s)
Gingivitis/epidemiología , Conocimientos, Actitudes y Práctica en Salud , Higiene Bucal , Aceptación de la Atención de Salud , Mujeres Embarazadas/psicología , Estudios Transversales , Caries Dental/epidemiología , Caries Dental/etiología , Caries Dental/prevención & control , Femenino , Gingivitis/etnología , Conductas Relacionadas con la Salud , Humanos , Nepal/epidemiología , Aceptación de la Atención de Salud/etnología , Aceptación de la Atención de Salud/psicología , Vigilancia de la Población , Embarazo , Prevalencia , Factores de Riesgo
4.
BMC Oral Health ; 18(1): 97, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29859084

RESUMEN

BACKGROUND: Oral health behavior and attitudes of pregnant women in low-income countries are rarely examined, yet should be considered when designing preventative or therapeutic studies to reduce burden of oral diseases. We aimed to understand dental care-seeking behavior, as well as oral health knowledge and attitudes of oral health among pregnant women in rural Nepal. METHODS: Semi-structured in-depth interviews (n = 16) and focus group discussions (3 groups, n = 23) were conducted among pregnant and recently-delivered women in Sarlahi, Nepal. Transcripts were translated from the local language to English then analyzed using a hybrid approach to thematic coding with Atlas.ti version 7. RESULTS: Women felt confident describing the signs and symptoms of tooth decay and gum disease, but were not knowledgeable about where to receive care for tooth and/or gum pain and relied heavily on the knowledge of their community. Some women used a toothbrush and toothpaste at least once a day to clean their teeth, but many reported the traditional use of a branch of a local shrub or tree as their teeth cleaning instrument. Women suggested a willingness to consider using an oral rinse throughout pregnancy, perceiving that it might have a positive impact on infant health. CONCLUSIONS: Future studies should focus on providing adequate and sustainable resources for pregnant women in Nepal and other low income settings to engage in good oral health behaviors (possibly supported through community-based workers), to maintain dental hygiene, and to access qualified dentists as a means of improving their oral health. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01177111 (Nepal Oil Massage Study) and NCT02788786 (Pilot Trial).


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Salud Bucal , Aceptación de la Atención de Salud , Mujeres Embarazadas/psicología , Adolescente , Adulto , Caries Dental/etiología , Caries Dental/prevención & control , Países en Desarrollo , Femenino , Conductas Relacionadas con la Salud , Humanos , Nepal , Enfermedades Periodontales/etiología , Enfermedades Periodontales/prevención & control , Embarazo , Investigación Cualitativa , Salud Rural , Cepillado Dental , Adulto Joven
5.
Int Endod J ; 49(4): 334-42, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26011008

RESUMEN

AIM: To evaluate whether the presence of apical periodontitis (AP), root canal treatment (RCT) and endodontic burden (EB) - as the sum of AP and RCT sites - were associated with long-term risk of incident cardiovascular events (CVE), including cardiovascular-related mortality, using data on participants in the Baltimore Longitudinal Study of Ageing (BLSA). METHODOLOGY: This retrospective cohort included 278 dentate participants in the BLSA with complete medical and dental examinations. Periodontal disease (PD) and missing teeth were recorded. The total number of AP and RCT sites was determined from panoramic radiographs. EB was calculated as the sum of AP and RCT sites. Oral inflammatory burden (OIB) was calculated combining PD and EB. The main outcome was incident CVE including angina, myocardial infarction and cardiovascular-related death. Participants were monitored for up to 44 years (mean = 17.4± 11.1 years) following dental examination. Relative risks (RRs) were calculated through Poisson regression models, estimating the relationship between AP, RCT, EB, PD, OIB and incident CVE. RESULTS: Mean age at baseline was 55.0 ±16.8 years and 51.4% were men. Sixty-two participants (22.3%) developed CVE. Bivariate analysis showed that PD, EB, number of teeth and OIB were associated with incident CVE. Multivariate models, adjusted for socio-demographic and medical variables, showed that age ≥60 years (RR = 3.07, 95% CI =1.68-5.62), hypertension (RR = 2.0, 95% CI = 1.16-3.46) and EB ≥3 (RR = 1.77, 95% CI = 1.04-3.02) were independently associated with incident CVE. The association between OIB and incident CVE was reduced to nonsignificance after adjustments (RR = 1.97, 95% CI = 0.83-4.70). CONCLUSIONS: EB in midlife was an independent predictor of CVE amongst community-dwelling participants in the BLSA. Prospective studies are required to evaluate cardiovascular risk reduction with the treatment of AP.


Asunto(s)
Enfermedades Cardiovasculares/epidemiología , Periodontitis Periapical/epidemiología , Periodontitis Periapical/terapia , Tratamiento del Conducto Radicular , Baltimore , Enfermedades Cardiovasculares/mortalidad , Femenino , Humanos , Incidencia , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo
6.
Science ; 158(3809): 1692-3, 1967 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-6059649

RESUMEN

Low-level activities of iodine-131, barium-140, and strontium-89 were found in a series of rain samples collected at Fayetteville, Arkansas, during the period from late June through August 1967. The ratios of these short-lived isotopes to strontium-90 were determined as accurately as possible. The data indicate that the debris from the Chinese nuclear explosion was injected primarily into the stratosphere.


Asunto(s)
Monitoreo de Radiación , Ceniza Radiactiva , Arkansas , Bario/análisis , Isótopos de Yodo/análisis , Radioisótopos , Isótopos de Estroncio/análisis
7.
J Periodontal Res ; 43(5): 500-7, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18565132

RESUMEN

BACKGROUND AND OBJECTIVE: Dietary manipulation, including caloric restriction, has been shown to impact host response capabilities significantly, particularly in association with aging. This investigation compared systemic inflammatory and immune-response molecules in rhesus monkeys (Macaca mulatta). MATERIAL AND METHODS: Monkeys on continuous long-term calorie-restricted diets and a matched group of animals on a control ad libitum diet, were examined for systemic response profiles including the effects of both gender and aging. RESULTS: The results demonstrated that haptoglobin and alpha1-antiglycoprotein levels were elevated in the serum of male monkeys. Serum IgG responses to Campylobacter rectus, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were significantly elevated in female monkeys. While only the antibody to Fusobacterium nucleatum was significantly affected by the calorie-restricted diet in female monkeys, antibody levels to Prevotella intermedia, C. rectus and Treponema denticola demonstrated a similar trend. CONCLUSION: In this investigation, only certain serum antibody levels were influenced by the age of male animals, which was seemingly related to increasing clinical disease in this gender. More generally, analytes were modulated by gender and/or diet in this oral model system of mucosal microbial challenge.


Asunto(s)
Envejecimiento/fisiología , Restricción Calórica , Inflamación/inmunología , Factores Sexuales , Proteínas de Fase Aguda/análisis , Animales , Anticuerpos Antibacterianos/sangre , Bacterias Anaerobias/inmunología , Femenino , Inmunidad Mucosa/fisiología , Inmunoglobulina G/sangre , Inflamación/sangre , Modelos Lineales , Macaca mulatta , Masculino , Enfermedades Periodontales/inmunología , Enfermedades Periodontales/microbiología
8.
Madridge J Dent Oral Surg ; 3(1): 85-90, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30906931

RESUMEN

High citrate concentration is a major component in the structure of craniofacial bone, teeth and periodontal tissues of humans and other osteovertebrates. It is now established that citrate incorporation into the apatite/collagen complex of bone is essential for the manifestation of the important biomechanical properties of bone; such as stability, strength, and resistance to fracture. The osteoblasts are specialized citrate-producing cells that provide the citrate incorporated in bone during osteogenic stem cell differentiation for production of new bone; "citration" that occurs in concert with mineralization. Dentin and cementum contain high citrate levels; as contrasted with low citrate in enamel. There exists no information regarding the status and source of incorporated citrate in dentin or in cementum. These are important issues relating to oral, periodontal, craniofacial structures. For example, repair of defects should include new tissue that exhibits the composition, structure, and biomechanical properties of the "normal" tissue; which cannot be achieved in the absence of citrate incorporation in the new tissues. Unfortunately, the presence and role of citrate in these tissues have been largely ignored and unrecognized over the past about 40 years by the dental and medical community. The intent of this review is to re-establish the interest and research regarding the important citrate relationships and issues; with focus on related interests in dentistry.

9.
J Dent Res ; 96(8): 855-863, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28530844

RESUMEN

Dental caries is prevalent, and secondary caries causes restoration failures. This article reviews recent studies on developing a new generation of bioactive resins with anticaries properties. Extensive effects were made to develop new antimicrobial composites, bonding agents, and other resins containing quaternary ammonium methacrylates to suppress plaque buildup and bacterial acid production. The effects of alkyl chain length and charge density and the antimicrobial mechanisms for chlorhexidine, nano-silver, quaternary ammonium methacrylates, and protein-repellent agents were discussed. Synergistic effects of contact-killing and protein-repellent properties were shown to yield the greatest biofilm-inhibition effects. The combination of antimicrobial, protein-repellent, and calcium phosphate nanoparticle remineralization was suggested to provide maximal anticaries effects. In addition, for use orally, cytotoxicity and biocompatibility were important considerations for the new bioactive materials. Furthermore, rather than kill all bacteria, it would be more desirable to modulate the oral biofilm compositions via bioactive resins to suppress cariogenic/pathogenic species and promote benign species. For widespread clinical use of the new antimicrobial and therapeutic materials, whether they would induce bacterial drug resistance needs to be determined, which requires further study. Nonetheless, the new generation of bioactive anticaries resins with therapeutic and biofilm acid-inhibiting properties has the potential to substantially benefit oral health.


Asunto(s)
Antiinfecciosos/farmacología , Cariostáticos/farmacología , Caries Dental/microbiología , Caries Dental/prevención & control , Resinas Sintéticas/farmacología , Materiales Biocompatibles/farmacología , Biopelículas/efectos de los fármacos , Fosfatos de Calcio/farmacología , Clorhexidina/farmacología , Placa Dental/microbiología , Placa Dental/prevención & control , Humanos , Metacrilatos/farmacología , Nanopartículas , Compuestos de Amonio Cuaternario/farmacología
10.
Nucleic Acids Res ; 29(20): 4251-6, 2001 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-11600714

RESUMEN

In the course of exploring the hybridization properties of glass DNA microarrays, multi-stranded DNA structures were observed that could not be accounted for by classical Watson-Crick base pairing. Non-denatured double-stranded DNA array elements were shown to hybridize to single-stranded (ss)DNA probes. Similarly, ssDNA array elements were shown to bind duplex DNA probes. This led to a series of experiments demonstrating the formation of multi-stranded DNA structures on the surface of microarrays. These structures were observed with a number of heterogeneous sequences, including both purine and pyrimidine bases, with shared sequence identity between the ssDNA and one of the duplex strands. Furthermore, we observed a strong binding preference near the ends of duplexes containing a 3'-homologous strand. We suggest that such binding interactions on cationic solid surfaces could serve as a model for a number of biological processes mediated through multi-stranded DNA.


Asunto(s)
ADN/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Modelos Genéticos , Conformación de Ácido Nucleico , Hibridación de Ácido Nucleico/métodos , Oligonucleótidos/metabolismo , Reacción en Cadena de la Polimerasa
11.
Clin Cancer Res ; 6(5): 2094-103, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10815937

RESUMEN

Chemically stabilized hammerhead ribozymes are nuclease-resistant, RNA-based oligonucleotides that selectively bind and cleave specific target RNAs. Due to their potential for specifically inhibiting gene expression, ribozymes are being investigated for therapeutic applications as well as for the elucidation of gene function. In particular, we have investigated ribozymes that target the mRNA of the vascular endothelial growth factor (VEGF) receptors because VEGF signaling is an important mediator of tumor angiogenesis and metastasis. Here we report pharmacodynamic studies testing anti-Flt-1 (VEGFR-1) and anti-KDR (VEGFR-2) ribozymes in animal models of solid tumor growth and metastasis. Ribozymes targeting either Flt-1 or KDR significantly inhibited primary tumor growth in a highly metastatic variant of Lewis lung carcinoma. However, only treatment with the anti-Flt-1 ribozyme resulted in a statistically significant and dose-dependent inhibition of lung metastasis in this model. The anti-Flt-1 ribozyme was then tested in a xenograft model of human metastatic colorectal cancer in which significant inhibition of liver metastasis was observed. Taken together, these data represent the first demonstration that synthetic ribozymes targeting VEGF receptor mRNA reduced the growth and metastasis of solid tumors in vivo.


Asunto(s)
Antineoplásicos/uso terapéutico , Metástasis de la Neoplasia/prevención & control , ARN Catalítico/uso terapéutico , ARN Mensajero/antagonistas & inhibidores , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Receptores de Factores de Crecimiento/antagonistas & inhibidores , Animales , Carcinoma Pulmonar de Lewis/tratamiento farmacológico , Carcinoma Pulmonar de Lewis/patología , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Neoplasias Hepáticas/prevención & control , Neoplasias Hepáticas/secundario , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Desnudos , Trasplante de Neoplasias , ARN Catalítico/genética , ARN Mensajero/genética , Proteínas Tirosina Quinasas Receptoras/genética , Receptores de Factores de Crecimiento/genética , Receptores de Factores de Crecimiento Endotelial Vascular , Trasplante Heterólogo , Células Tumorales Cultivadas
12.
Neurobiol Aging ; 3(4): 287-97, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-7170046

RESUMEN

This literature review of research on age-related differences in sleep and rhythmic phenomena in laboratory animals covers three general areas: (1) age-related differences in biorhythms in general; (2) age-related differences in sleep patterns as assessed by psychophysiological measures; and (3) neurobiological correlates of biorhythms and sleep, including consideration of possible morphological, chemical, and endocrine bases of age-related defects in animal models. It is concluded that systematic research bridging these areas is lacking although several promising areas have been explored.


Asunto(s)
Envejecimiento , Gatos/fisiología , Ritmo Circadiano , Ratones/fisiología , Ratas/fisiología , Sueño/fisiología , Animales , Hormonas/fisiología , Locus Coeruleus/fisiología , Melatonina/fisiología , Norepinefrina/fisiología , Glándula Pineal/fisiología , Puente/fisiología , Retina/fisiología , Serotonina/fisiología , Núcleo Supraquiasmático/fisiología
13.
Neurobiol Aging ; 4(2): 157-61, 1983.
Artículo en Inglés | MEDLINE | ID: mdl-6633785

RESUMEN

The effect of age on the behavioral response to methadone hydrochloride was examined in male C57BL/6J mice. After 1 hr habituation to an oval runway, locomotor activity of young (6-8 months) and aged (30-32 months) mice was monitored for 3 hr following injections of saline or methadone hydrochloride (2.5, 7.5, 15.0 or 22.5 mg/kg). The three highest doses initially elevated activity which then declined over the next 1 1/2 to 2 1/2 hr. Compared to young mice, activity of aged mice was elevated less extensively, but remained elevated for a longer period of time. The attenuated elevation could be interpreted in terms of reduced physical capacity of aged mice; however, the more prolonged elevation was clearly an age-related difference in reaction to the drug. Although the mechanism accountable for this effect is unknown, it is not likely related to age differences in drug absorption or distribution to active sites.


Asunto(s)
Metadona/farmacología , Actividad Motora/efectos de los fármacos , Factores de Edad , Animales , Relación Dosis-Respuesta a Droga , Locomoción/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Factores de Tiempo
14.
Neurobiol Aging ; 2(3): 221-7, 1981.
Artículo en Inglés | MEDLINE | ID: mdl-7312100

RESUMEN

The performance of male A/J and C57BL/6J mice from three age groups (4, 18, and 24 months) was observed in a battery of tests designed to assess age-related impairments in motor abilities. A/J mice were superior to C57BL/6J mice in tasks requiring upper body strength, such as tests of grip strength and tightrope performance. C57BL/6J mice were superior performers in tasks requiring balance and coordination, such as movement on stationary and rotating rods. In addition, the C57BL/6J strain generally exhibited greater locomotor activity, such as measured in open field and wheel-running tests. Significant age-related deficits were observe among A/J mice in tests of grip strength, balance rod, rotorod, and wheel activity; and among C57BL/6J mice, in balance, rod, tightrope, exploratory activity, and wheel activity tests. Except for scores of exploratory activity (free versus forced exploration), the test measures tended to be uncorrelated; however, the degree and magnitude of intercorrelation among test scores increased with age. The results underscore the need to consider genotype in the assessment of age-related motor impairments in animal models.


Asunto(s)
Envejecimiento , Conducta Animal/fisiología , Actividad Motora/fisiología , Animales , Conducta Exploratoria/fisiología , Genotipo , Masculino , Ratones , Ratones Endogámicos A , Ratones Endogámicos C57BL
15.
Mech Ageing Dev ; 30(2): 143-52, 1985 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-4021553

RESUMEN

An age-related decline in the capacity for thermoregulation among homeothermic animals has been observed frequently under conditions of extreme ambient temperatures. We investigated the temporal stability of the internal body temperature of 69 C57BL/6J mice from 25 months of age until death in a controlled, neutral thermal environment. Estimates of temporal variability were calculated over consecutive 1-month intervals using (colonic) body temperature data collected weekly. The results of this longitudinal analysis indicated that the regulation of body temperature, as measured by its temporal stability, became increasingly less precise with advancing age. Body temperature exhibited a significant decline as the animal approached death. Individual differences in body temperature and the temporal regulation of body temperature were significantly correlated with lifespan, although the direction of the relations were opposite. Body temperature correlated positively with lifespan, whereas the temporal stability of body temperature correlated negatively with lifespan. Thus, animals exhibiting higher body temperatures and greater temporal stability also tended to live longer than their cohorts.


Asunto(s)
Envejecimiento , Temperatura Corporal , Esperanza de Vida , Animales , Regulación de la Temperatura Corporal , Masculino , Ratones , Ratones Endogámicos C57BL
16.
Mech Ageing Dev ; 20(3): 253-66, 1982 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7162222

RESUMEN

Data from nine inbred and six hybrid mouse strains of both sexes were used in a correlational analysis to examine the relationships between lifespan and several growth parameters, including body weight at weaning, at 6 weeks after weaning, and at 1 year, and estimates of growth rate, food consumption, and feeding efficiency during early life. The analysis revealed strong relationships of genotype to all variables. Hybridization was associated with longer lifespan, but sex was not related to lifespan. Several growth parameters were significantly related to lifespan, but the directions of the correlations were sex-dependent. Several body weight and growth parameters were positively correlated to lifespan in males, while negatively correlated to lifespan in females. Genotype accounted for most of the variance in these relationships with the exception of hybrid males, where the correlation between growth rate and lifespan was attributable largely to environmental factors. In demonstrating significant correlations between lifespan and constitutional variables within a species, the results supported a morphogenetically based hypothesis of lifespan inheritance; however, the sex differential in the direction of the relationship between growth and lifespan further demonstrated the difficulty of making predictions deduced from the hypothesis.


Asunto(s)
Peso Corporal , Genotipo , Hibridación Genética , Longevidad , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos , Factores Sexuales
17.
Mech Ageing Dev ; 55(1): 69-87, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2402168

RESUMEN

Beginning at either 1.5, 6 or 10 months of age, male mice from the A/J and C57BL/6J strains and their F1 hybrid, B6AF1/J were fed a diet (4.2 kcal/g) either ad libitum every day or in a restricted fashion by ad libitum feeding every other day. Relative to estimates for ad libitum controls, the body weights of the intermittently-fed restricted C57BL/6J and hybrid mice were reduced and mean and maximum life span were incremented when the every-other-day regimen was initiated at 1.5 or 6 months of age. When every-other-day feeding was introduced at 10 months of age, again both these genotypes lost body weight relative to controls; however, mean life span was not significantly affected although maximum life span was increased. Among A/J mice, intermittent feeding did not reduce body weight relative to ad libitum controls when introduced at 1.5 or 10 months of age; however, this treatment did increase mean and maximum life span when begun at 1.5 months, while it decreased mean and maximum life span when begun at 10 months. When restricted feeding was introduced to this genotype at 6 months of age, body weight reduction compared to control values was apparent at some ages, but the treatment had no significant effects on mean or maximum life span. These results illustrate that the effects of particular regimens of dietary restriction on body weight and life span are greatly dependent upon the genotype and age of initiation. Moreover, when examining the relationship of body weight to life span both between and within the various groups, it was clear that the complexity of this relationship made it difficult to predict that lower body weight would induce life span increment.


Asunto(s)
Envejecimiento/fisiología , Peso Corporal/fisiología , Ingestión de Alimentos/fisiología , Longevidad/fisiología , Animales , Genotipo , Crecimiento/fisiología , Masculino , Ratones , Ratones Endogámicos A , Ratones Endogámicos C57BL , Ratones Endogámicos , Especificidad de la Especie
18.
J Med Chem ; 22(6): 614-7, 1979 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-458817

RESUMEN

The inhibitory effect for a set of 23 5-(X-benzyl)-2,4-diaminopyrimidines acting on bovine liver dihydrofolate reductase (DHFR) had led to the following quantitative structure-activity relationship (QSAR): log 1/C = 0.62pi3 + 0.33epsilon sigma + 4.99, where r = 0.931 and s = 0.146. C in this expression is the molar concentration of inhibitor producing 50% inhibition, pi3 is the hydrophobic parameter for substituents on the 3 position of the phenyl moiety, and epsilon sigma is the the sum of the Hammett sigma constants for the 3, 4, and 5 substituents of the phenyl ring.


Asunto(s)
Antagonistas del Ácido Fólico , Hígado/enzimología , Pirimidinas/farmacología , Animales , Bovinos , Técnicas In Vitro , Hígado/efectos de los fármacos , Modelos Biológicos , Pirimidinas/síntesis química , Relación Estructura-Actividad
19.
J Med Chem ; 23(11): 1205-12, 1980 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7005446

RESUMEN

A quantitative structure-activity relationship (QSAR) has been formulated for the inhibition of purified E. coli dihydrofolate reductase by 23 5-(substituted benzyl)-2,4-diaminopyrimidines: log 1/C = 1.14MR'3,4,5 + 5.73; r = 0.887; s = 0.285. In this expression, MR'3,4,5 refers to the sum of MR values for X in the 3, 4 and 5 positions of the phenyl moiety. MR' signifies that the effective value of MR is limited to 0.79. Comparison of the QSAR for E. coli enzyme inhibition with that previously obtained for bovine enzyme offers the first general explanation for the great selectivity of the important antibacterial agent trimethoprim. Such QSSR promise to be of value in devising more selective drugs.


Asunto(s)
Escherichia coli/enzimología , Antagonistas del Ácido Fólico , Hígado/enzimología , Pirimidinas/síntesis química , Animales , Bovinos , Cinética , Modelos Teóricos , Pirimidinas/farmacología , Relación Estructura-Actividad
20.
Biotechniques ; 31(5): 1182, 1184, 1186 passim, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11730025

RESUMEN

Glass cDNA microarrays can be used to profile the expression of thousands of gene targets in a single experiment. However, the potential for hybridization cross-reactivity needs to be considered when interpreting the results. Here, we describe hybridization experiments with a model array representing four distinct functional classes (families): chemokines, cytochrome P-450 isozymes, G proteins, and proteases. The cDNA clones selected for this array exhibited pairwise sequence identities ranging from 55% to 100%, as determined by a homology scoring algorithm (LALIGN). Targets for microarraying were amplified by PCR and spotted in 4-fold replication for signal averaging. One designated target from each family was further amplified by PCR to incorporate a T7 promoter sequence for the production of synthetic RNA transcripts. These transcripts were used to generate fluorescent hybridization probes by reverse transcription at varying input concentrations. As expected, hybridization signals were highest at the matching target elements. Targets containing less than 80% sequence identity relative to the hybridization probe sequences showed cross-reactivities ranging from 0.6% to 12%. Targets containing greater than 80% identity showed higher cross-reactivities (26%-57%). These cross-reactive signals were analyzed for statistical correlation with the length of sequence overlap, percent sequence identity, and homology score determined by LALIGN. Overall, percent sequence identity was the best predictor of hybridization cross-reactivity. These results provide useful guidelines for interpreting glass cDNA microarray data.


Asunto(s)
Cruzamientos Genéticos , Análisis de Secuencia por Matrices de Oligonucleótidos , Algoritmos , Quimiocinas/genética , Sistema Enzimático del Citocromo P-450/genética , Proteínas de Unión al GTP/genética , Perfilación de la Expresión Génica , Metaloendopeptidasas/genética , Hibridación de Ácido Nucleico , Serina Endopeptidasas/genética
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