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1.
BMC Genomics ; 19(1): 900, 2018 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-30537932

RESUMEN

BACKGROUND: To reduce costs of rearing replacement heifers, researchers have focused on decreasing age at breeding and first calving. To increase returns upon initiation of lactation the focus has been on increasing mammary development prior to onset of first lactation. Enhanced plane of nutrition pre-weaning may benefit the entire replacement heifer operation by promoting mammary gland development and greater future production. METHODS: Twelve Holstein heifer calves (< 1 week old) were reared on 1 of 2 dietary treatments (n = 6/group) for 8 weeks: a control group fed a restricted milk replacer at 0.45 kg/d (R, 20% crude protein, 20% fat), or an accelerated group fed an enhanced milk replacer at 1.13 kg/d (EH, 28% crude protein, 25% fat). At weaning (8 weeks), calves were euthanized and sub-samples of mammary parenchyma (PAR) and mammary fat pad (MFP) were harvested upon removal from the body. Total RNA from both tissues was extracted and sequenced using the Illumina HiSeq2500 platform. The Dynamic Impact Approach (DIA) and Ingenuity Pathway Analysis (IPA) were used for pathway analysis and functions, gene networks, and cross-talk analyses of the two tissues. RESULTS: When comparing EH vs R 1561 genes (895 upregulated, 666 downregulated) and 970 genes (506 upregulated, 464 downregulated) were differentially expressed in PAR and MFP, respectively. DIA and IPA results highlight a greater proliferation and differentiation activity in both PAR and MFP, supported by an increased metabolic activity. When calves were fed EH, the PAR displayed transcriptional signs of greater overall organ development, with higher ductal growth and branching, together with a supportive blood vessel and nerve network. These activities were mediated by intracellular cascades, such as AKT, SHH, MAPK, and Wnt, probably activated by hormones, growth factors, and endogenous molecules. The analysis also revealed strong communication between MFP and PAR. CONCLUSION: The transcriptomics and bioinformatics approach highlighted key mechanisms that mediate the mammary gland response to a higher plane of nutrition in the pre-weaning period.


Asunto(s)
Tejido Adiposo/metabolismo , Glándulas Mamarias Animales/crecimiento & desarrollo , Glándulas Mamarias Animales/metabolismo , Estado Nutricional/genética , Transcriptoma/genética , Destete , Animales , Bovinos , Femenino , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ARN
2.
J Anim Sci ; 95(8): 3540-3551, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28805891

RESUMEN

Five ruminally fistulated steers were used in a 5 × 5 Latin square design to determine the effects of increasing dietary fat and sulfur from condensed distiller's solubles (CDS) on the ruminal microbiome. Treatments included a corn-based control (CON) and 4 levels of CDS (0, 10, 19, and 27%) in a coproduct-based (corn gluten feed and soybean hulls) diet. Fat concentrations were 1.79, 4.43, 6.80, and 8.91% for diets containing 0, 10, 19, and 27% CDS, respectively. Steers were fed for ad libitum intake once daily. After feeding each diet for 18 d, ruminal samples were collected 3 h after feeding on d 19. Samples were separated into solid and liquid fractions. Microbial DNA was extracted for bacterial analysis using paired-end sequencing of the V3 through V4 region of the 16S rRNA gene on the MiSeq Illumina platform and quantitative PCR of selected species. Orthogonal contrasts were used to determine linear and quadratic effects of CDS inclusion. Increasing CDS inclusion decreased (linear, < 0.05) α-diversity and species richness in the liquid fraction. Analysis of Bray-Curtis similarity indicated a treatment effect ( = 0.01) in the liquid fraction. At the phyla level, relative abundance of Bacteroidetes decreased in steers fed increasing dietary inclusion of CDS as Firmicutes increased to 82% of sequences for the 27% CDS treatment. Family Ruminococcaceae increased (linear, < 0.01) 2-fold in the liquid fraction when feeding CDS increased from 0 to 27% CDS, yet genera tended ( = 0.09) to decrease in steers fed greater CDS. The most abundant family of sulfate-reducing bacteria, Desulfovibrionaceae, increased ( < 0.03) in the solid and liquid fraction in steers fed additional dietary CDS and sulfur. Relative abundance of family Veillonellaceae and were increased (linear, ≤ 0.02) in the solid fraction as steers were fed increasing CDS. There were no effects ( > 0.10) of feeding increasing dietary fat from CDS on fibroylytic genus in either fraction. Results demonstrate increasing fat and sulfur from CDS in a coproduct-based diet markedly alters the liquid fraction ruminal microbiome but does not elicit negative effects on relative abundance of identified fiber-fermenting bacteria.


Asunto(s)
Bacterias/efectos de los fármacos , Bovinos/fisiología , Grasas de la Dieta/farmacología , Suplementos Dietéticos , Microbiota/efectos de los fármacos , Azufre/farmacología , Alimentación Animal , Animales , Bacterias/clasificación , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bovinos/microbiología , Dieta/veterinaria , Fibras de la Dieta/metabolismo , Digestión/efectos de los fármacos , Fermentación/efectos de los fármacos , Masculino , Rumen/microbiología , Glycine max , Zea mays
3.
J Anim Sci ; 95(1): 387-394, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28177369

RESUMEN

Seven ruminally cannulated Brahman steers were used in a 7 × 4 incomplete block design to determine the effects of cottonseed meal (CSM; 43.9% CP, 82.9% RDP) or dried distillers' grains (DDG; 27.5% CP, 43.6% RDP) supplementation on rice straw utilization (47 g/kg CP and 681 g/kg NDF). Treatments consisted of a negative control receiving no supplement (control) and 3 levels (60, 120, and 180 mg N/kg BW) of either CSM or DDG. Periods were 14 d with 8 d for adaptation and 6 d for data collection. Steers had ad libitum access to rice straw and were fed supplements daily. Increased supplementation resulted in a linear increase ( ≤ 0.06) in forage OM intake from 13.5 g/kg BW by controls to 15.5 and 16.1 g/kg BW for 180 mg N/kg BW of DDG and CSM, respectively. No differences between sources were observed ( = 0.84). Total digestible OM intake was increased by supplementation (linear, < 0.01) from 6.9 g/kg BW (control) to 10.0 and 11.2 g/kg BW for 180 mg N/kg BW of CSM and DDG, respectively. A greater response was observed for DDG ( = 0.05) due to greater provision of supplement (g DM/d) to achieve isonitrogenous treatment levels. Total tract OM digestion tended to increase with DDG supplementation (linear, = 0.08) but not CSM supplementation ( = 0.19). Both supplements did not affect NDF digestion ( > 0.40) or calculated forage NDF digestibility ( > 0.40). Ruminal ammonia concentrations peaked 4 h after supplementation/feeding with the greatest concentration (4.0 m) observed for 180 mg N/kg BW of CSM and the lowest concentration at 4 h observed in the control (0.8 m). Provision of CSM resulted in a linear increase ( < 0.01) in average ruminal ammonia, in contrast to the quadratic response ( = 0.02) observed with DDG supplementation. Total VFA production linearly increased for both CSM and DDG supplementation ( = 0.09 and = 0.01, respectively). Protein supplements containing high and low levels of RDP were effective at improving intake and utilization of rice straw by Brahman steers.


Asunto(s)
Alimentación Animal/análisis , Proteínas en la Dieta/farmacología , Suplementos Dietéticos , Oryza/química , Rumen/metabolismo , Amoníaco/metabolismo , Animales , Proteínas en la Dieta/análisis , Digestión/fisiología , Ingestión de Alimentos/fisiología , Fermentación , Masculino , Tallos de la Planta/química , Tallos de la Planta/metabolismo
4.
J Anim Sci ; 95(1): 308-319, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28177388

RESUMEN

Effects of a -based direct-fed microbial (DFM) on growth performance, plasma tumor necrosis factor ɑ (TNFɑ), relative gene expression, and intestinal VFA concentrations in weanling pigs fed low- or high-fiber diets were evaluated. Two hundred pigs (initial BW: 6.31 ± 0.73 kg) were allotted to 1 of 4 dietary treatments (5 pigs per pen and 10 pens per treatment). Treatments were arranged in a 2 × 2 factorial design with 2 diet types [low-fiber (LF) or high-fiber (HF)] and 2 concentrations of DFM (0 or 60 g DFM/t of feed). The DFM contained 1.5 × 10 cfu/g and was obtained from Danisco Animal Nutrition-DuPont Industrial Biosciences, Marlborough, UK. Phase 1 diets were fed for 2 wk post-weaning and phase 2 diets were fed over the following 29 d. Low fiber diets contained corn and soybean meal as main ingredients and HF diets contained corn, soybean meal, corn distillers dried grains with solubles (7.5 and 15.0% in phase 1 and 2, respectively), and wheat middlings (10.0%). Pigs and feed were weighed at the start and at the end of each phase, and ADG, ADFI, and G:F were calculated. At the conclusion of phase 2, blood was collected from 1 pig per pen and 1 pig per pen was sacrificed. Cecum and rectum contents were analyzed for VFA, and tissue samples were collected from the ileum, cecum, rectum, and liver to determine expression of genes related to absorption and metabolism of VFA using quantitative reverse transcription-PCR. Results indicated that feeding HF diets reduced ( ≤ 0.05) ADFI and ADG of pigs compared with feeding LF diets. Pigs fed DFM diets had improved ( ≤ 0.05) G:F compared with pigs fed non-DFM diets. Pigs fed LF diets had greater ( ≤ 0.05) BW at the end of phase 2 compared with pigs fed HF diets. The concentration of VFA in rectum contents was greater ( ≤ 0.05) in pigs fed LF diets than in pigs fed HF diets. The expression of in the rectum of pigs fed HF diets was greater ( ≤ 0.05) than for pigs fed LF diets, and pigs fed DFM-containing diets had an increased ( ≤ 0.05) expression of in the liver. Pigs fed HF diets had greater ( ≤ 0.05) concentrations of urea N in plasma compared with pigs fed LF diets, but dietary fiber and DFM had no effect on plasma concentration of TNF-ɑ. In conclusion, the -based DFM improved overall G:F of weanling pigs, but pigs fed LF diets had greater final BW than pigs fed HF diets.


Asunto(s)
Alimentación Animal/análisis , Bacillus/fisiología , Fibras de la Dieta/administración & dosificación , Ácidos Grasos Volátiles/metabolismo , Regulación de la Expresión Génica/fisiología , Porcinos/fisiología , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Fibras de la Dieta/farmacología , Femenino , Masculino , Probióticos
5.
J Anim Sci ; 95(11): 5077-5090, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29293739

RESUMEN

The objective of this study was to determine bacterial community profiles of the equine cecum in response to abrupt inclusion of varying levels of dietary starch. Seven cecally cannulated Quarter Horse geldings (497 to 580 kg) were used in a crossover design with two 28-d periods and a 28-d washout between each. Horses were randomly assigned to dietary treatments consisting of a commercial concentrate offered as fed at either 0.6 (low starch [LS]) or 1.2% BW (high starch [HS]) daily that was divided into 2 meals at 12-h intervals. Prior to the start of each period, horses were allowed ad libitum access to coastal bermudagrass () hay. Concentrate was fed on d 1 with no adaptation. Cecal fluid was collected on d 1 at h 0 and at 3, 6, 9, and 12 h relative to the initial concentrate meal on d 1. Additional samples were collected 6 h after feeding on d 2, 3, and 7 of each period. Cecal contents were used to determine pH and VFA concentrations and extract microbial DNA. The V4 through V6 region of 16S rRNA gene was amplified using PCR and sequenced on the Roche 454 FLX platform. Sequence analysis was performed with QIIME, and data were analyzed using the MIXED procedure of SAS. Cecal pH tended to decrease ( = 0.09) in horses fed HS in the first 12 h after the first concentrate meal and remained lower ( ≤ 0.05) the following 7 d. Total VFA were greater ( ≤ 0.05) in horses fed HS in the initial 12 h and 7 d after addition of concentrate. Species richness determined using the Chao1 index was unchanged ( > 0.20) over the initial 12 h and decreased ( = 0.01) over 7 d for both treatments. Community diversity determined using the Shannon index tended to decrease ( = 0.06) over the 7 d. Relative abundances of Paraprevotellaceae were greater ( ≤ 0.05) in HS in the first 12 h. Over 7 d, relative abundances of Paraprevotellaceae, Veillonellaceae, and Succinivibrionaceae were greater ( ≤ 0.05) in HS compared with LS. Abrupt and short-term exposure to dietary starch does alter cecal fermentation and microbial community structure in horses, but the impact on horse health is unknown.


Asunto(s)
Alimentación Animal/análisis , Bacterias/clasificación , Carbohidratos de la Dieta/administración & dosificación , Caballos/fisiología , Microbiota , Almidón/administración & dosificación , Animales , Bacterias/genética , Ciego/microbiología , Dieta/veterinaria , Digestión , Ácidos Grasos Volátiles/metabolismo , Fermentación , Concentración de Iones de Hidrógeno , Masculino
6.
J Anim Sci ; 94(8): 3321-3334, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27695786

RESUMEN

Two experiments were conducted to determine the requirement for standardized total tract digestible (STTD) Ca by 11- to 25-kg pigs based on growth performance, bone ash, or Ca and P retention and to determine the effect of dietary Ca on expression of genes related to Ca transport in the jejunum and kidneys. Six diets were formulated to contain 0.36% STTD P and 0.32, 0.40, 0.48, 0.56, 0.64, or 0.72% STTD Ca by including increasing quantities of calcium carbonate in the diets at the expense of cornstarch. Two additional diets contained 0.72% STTD Ca and 0.33% or 0.40% STTD P to determine if 0.36% STTD P had negative effects on the Ca requirement. The same batch of all diets was used in both experiments. In Exp. 1, 256 pigs (11.39 ± 1.21 kg initial BW) were randomly allotted to the 8 diets with 4 pigs per pen and 8 replicate pens per diet in a randomized complete block design. On the last day of the experiment, 1 pig from each pen was euthanized and the right femur and intestine and kidney samples were collected. Results indicated that ADG and G:F started to decline (linear and quadratic, < 0.05) at 0.54 and 0.50% STTD Ca, respectively. In contrast, bone ash increased (quadratic, < 0.05) as dietary Ca increased and reached a plateau indicating that the requirement for STTD Ca to maximize bone ash was 0.48%. Bone ash, but not ADG or G:F, increased (linear, < 0.01) as STTD increased in the diets. The mRNA expression of genes related to transcellular Ca transport decreased (linear, < 0.01) in the jejunum and in kidneys (linear and quadratic, < 0.01) as dietary Ca increased. In Exp. 2, 80 pigs (13.12 ± 1.79 kg initial BW) were placed in metabolism crates and randomly allotted to the 8 diets with 10 replicate pigs per diet in a randomized complete block design. Fecal and urine samples were collected using the marker-to-marker approach. Results indicated that the requirement for STTD Ca to maximize Ca and P retention (g/d) was 0.60 and 0.49%, respectively. In conclusion, the STTD Ca requirement by 11- to 25-kg pigs to maximize bone ash was 0.48%; however, ADG and G:F declined if more than 0.54 or 0.50% STTD Ca, respectively, was fed, and the minimum concentration of Ca needed to maximize ADG and G:F could not be determined under the conditions of this experiment. Increasing dietary Ca decreased the mRNA expression of several genes related to transcellular Ca transport in the jejunum and the kidneys.


Asunto(s)
Calcio de la Dieta/metabolismo , Minerales/metabolismo , Fósforo Dietético/metabolismo , Porcinos/fisiología , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Carbonato de Calcio/metabolismo , Dieta/veterinaria , Heces , Femenino , Tracto Gastrointestinal/metabolismo , Mucosa Intestinal/metabolismo , Riñón/metabolismo , Masculino , Porcinos/genética , Porcinos/crecimiento & desarrollo
7.
J Anim Sci ; 93(12): 5554-74, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26641165

RESUMEN

The advent of high-throughput technologies to study an animal's genome, proteome, and metabolome (i.e., "omics" tools) constituted a setback to the use of reductionism in livestock research. More recent development of "next-generation sequencing" tools was instrumental in allowing in-depth studies of the microbiome in the rumen and other sections of the gastrointestinal tract. Omics, along with bioinformatics, constitutes the foundation of modern systems biology, a field of study widely used in model organisms (e.g., rodents, yeast, humans) to enhance understanding of the complex biological interactions occurring within cells and tissues at the gene, protein, and metabolite level. Application of systems biology concepts is ideal for the study of interactions between nutrition and physiological state with tissue and cell metabolism and function during key life stages of livestock species, including the transition from pregnancy to lactation, in utero development, or postnatal growth. Modern bioinformatic tools capable of discerning functional outcomes and biologically meaningful networks complement the ever-increasing ability to generate large molecular, microbial, and metabolite data sets. Simultaneous visualization of the complex intertissue adaptations to physiological state and nutrition can now be discerned. Studies to understand the linkages between the microbiome and the absorptive epithelium using the integrative approach are emerging. We present examples of new knowledge generated through the application of functional analyses of transcriptomic, proteomic, and metabolomic data sets encompassing nutritional management of dairy cows, pigs, and poultry. Published work to date underscores that the integrative approach across and within tissues may prove useful for fine-tuning nutritional management of livestock. An important goal during this process is to uncover key molecular players involved in the organismal adaptations to nutrition.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Biología Computacional , Ganado , Animales , Tracto Gastrointestinal/fisiología , Nutrigenómica
8.
J Anim Sci ; 92(11): 5063-75, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25349354

RESUMEN

Cattle consuming low-quality forages (LQF) require protein supplementation to increase forage utilization via ruminal fermentation. Biofuel production from algal biomass results in large quantities of postextraction algal residue (PEAR), which has the potential to elicit LQF utilization responses similar to cottonseed meal (CSM); however, its effect on ruminal bacterial communities is unknown. Five ruminally and duodenally cannulated Angus steers in a 5 × 5 Latin square had ad libitum access to oat straw diets. Treatments were infused ruminally and consisted of an unsupplemented control; PEAR at 50, 100, and 150 mg N/kg BW; and CSM at 100 mg N/kg BW. Ruminal samples were collected 4 h after supplementation on d 14 of each period and separated into solid and liquid fractions. Each sample was extracted for genomic DNA, PCR amplified for the V4 to V6 region of the 16S rRNA, sequenced on the 454 Roche pyrosequencing platform, and analyzed using the QIIME pipeline. Weighted UniFrac analysis and Morisita-Horn index demonstrated different community composition between liquid and solid fractions. Measures of richness including observed operational taxonomic units (OTU) and abundance coverage estimator metric decreased with greater PEAR provision (P ≤ 0.09). There were 42 core microbiome OTU observed in all solid fraction samples while the liquid fraction samples contained 30 core OTU. Bacteroidetes was the predominant phylum followed by Firmicutes in both fractions, which together characterized more than 90% of sequences. Relative abundance of Firmicutes increased with PEAR supplementation in the liquid fraction (linear, P = 0.02). Among Firmicutes, Lachnospiraceae, Ruminococcaceae, and Clostridiaceae families increased in the liquid fraction with greater PEAR supplementation (linear, P ≤ 0.03). Prevotella represented over 25% of sequences in all treatments, and relative abundance decreased in the solid fraction with increasing PEAR provision (linear, P = 0.01). Fibrobacter and Treponema decreased in the liquid fraction with increasing PEAR (linear, P < 0.10). Results suggest PEAR supplementation increased forage utilization by increasing members of Firmicutes within the liquid fraction of the rumen microbiome.


Asunto(s)
Alimentación Animal/análisis , Bovinos/fisiología , Rumen/microbiología , Animales , Bovinos/microbiología , Suplementos Dietéticos , Fermentación , Fibrobacter , Masculino , Reacción en Cadena de la Polimerasa
12.
Biol Blood Marrow Transplant ; 2(1): 37-43, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9078353

RESUMEN

Twenty patients with non-Hodgkin's lymphoma (NHL), primarily intermediate-and high-grade, were evaluated for evidence of bone marrow (BM) or peripheral blood stem cell (PBSC) lymphoma contamination using tumor-specific oligonucleotide-polymerase chain reaction (TSO-PCR). Patients were enrolled in a single-institution study comparing PBSC and bone marrow transplantation (BMT) for relapsed NHL. A molecular marker (CDR3 rearrangement, T cell beta receptor [TC beta R] rearrangement, or BCL-2/IgH rearrangement) was identified from analysis of the diagnostic tissue in 17 of 20 patients. Prior to undergoing BMT, 14 of 17 patients had PCR evidence of lymphoma involvement of either BM (11/17) or PBSCs (9/11). No decrease was found in the frequency of contamination of PBSCs compared with BM. In one patient, quantitative competitive PCR (C-PCR) identified a three- to tenfold greater quantity of contamination in the BM compared with PBSC. All evaluated patients (6/6) with contamination prior to BMT had persistence of marrow contamination following BMT. Our data demonstrate that TSO-PCR can generate a molecular marker for the majority of patients with intermediate- and high-grade NHL. In addition, we identified a high rate of occult lymphoma involvement in both BM and PBSC. As demonstrated by C-PCR, however, quantitative differences may exist in contamination of BM and PBSCs.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Linfoma no Hodgkin/terapia , Secuencia de Bases , Humanos , Linfoma no Hodgkin/patología , Datos de Secuencia Molecular , Neoplasia Residual/diagnóstico , Reacción en Cadena de la Polimerasa , Trasplante Autólogo
13.
J Laparoendosc Surg ; 1(5): 287-93, 1991 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1834281

RESUMEN

Operative common bile duct exploration, performed in conjunction with cholecystectomy, has been considered the treatment of choice for choledocholithiasis in the presence of an intact gallbladder. With the advent of laparoscopic cholecystectomy, the management of common bile duct stones has been affected. More emphasis is being placed on endoscopic sphincterotomy and options other than operative common duct exploration. Because of this increasing demand, we have developed a new technique for laparoscopic common bile duct exploration performed in the same operative setting as laparoscopic cholecystectomy. A series of five patients who successfully underwent common bile duct exploration, flexible choledochoscopy with stone extraction, and T-tube drainage, all using laparoscopic technique, is reported. Mean postoperative length of hospital stay was 4.6 days. Outpatient T-tube cholangiography was performed in all cases and revealed normal ductal anatomy with no retained stones. Follow-up ranged from 6 weeks to 4 months, and all patients were asymptomatic and had normal liver function tests.


Asunto(s)
Colecistectomía/métodos , Conducto Colédoco/patología , Endoscopía del Sistema Digestivo/métodos , Cálculos Biliares/cirugía , Laparoscopía , Adolescente , Adulto , Anciano , Colangiografía , Conducto Colédoco/cirugía , Drenaje , Endoscopía del Sistema Digestivo/instrumentación , Femenino , Estudios de Seguimiento , Humanos , Cuidados Intraoperatorios , Intubación/instrumentación , Masculino , Persona de Mediana Edad , Factores de Tiempo
14.
Bull Med Libr Assoc ; 78(3): 293-301, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2393758

RESUMEN

Nonprofessional library support staff traditionally hold what are considered to be low-paying, nonchallenging positions. These negative factors make retaining creative and productive employees difficult. This article outlines the approach taken at the Medical College of Georgia's Robert B. Greenblatt, M.D. Library to devise a structure of library staff positions that becomes progressively more demanding. A new nine-level Library Staff Classification Plan resulted. This plan also enables and encourages employees to acquire more skills and to accept more responsibility in order to qualify for higher-level library positions or to advance their present position to receive comparable rewards. The plan expresses the level of responsibilities expected, the employee qualifications desired, and lists representative duties across the spectrum of typical library tasks.


Asunto(s)
Bibliotecas Médicas/organización & administración , Administración de Personal/métodos , Georgia , Perfil Laboral , Desarrollo de Personal
16.
J Biol Response Mod ; 7(6): 559-67, 1988 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3265147

RESUMEN

The sensitivity of three human colon adenocarcinoma cell lines (LoVo, LS174T, and SW1116) and a human pancreatic adenocarcinoma cell line (Hs766T) to a recombinant ricin A chain-antitransferrin receptor immunotoxin was studied. In addition, the carboxylic ionophore monensin was used in conjunction with the immunotoxin to determine the possibility of increased cytotoxicity without loss of specificity. The immunotoxin, 454A12-rRTA, is composed of the monoclonal antibody 454A12 directed against transferrin receptor and of ricin A chain, which was produced by recombinant DNA techniques. In 18 h dose-response cytotoxicity assays, the median inhibitory dose (ID50) against LoVo, LS174T, and SW1116 was found to be 3 X 10(-10), 3.6 X 10(-11), and 3.6 X 10(-10) M, respectively; in the same assay, the ID50 for Hs766T was found to be 4 X 10(-10) M. In the presence of monensin, the ID50 for the adenocarcinoma cell lines was reduced 9-fold, 28-fold, and 5-fold, respectively. In cytotoxic kinetic assays, 50% of control protein inhibition was reached in immunotoxin-treated LS174T cells 12-fold faster in the presence of monensin than in its absence. Immunotoxin-treated LoVo cells reached 50% inhibition of control protein synthesis fivefold faster in the presence of monensin than in its absence. Furthermore, no toxicity of immunotoxin or potentiation by monensin was observed in either a control cell line (Swiss albino mouse 3T6) treated with specific immunotoxin or with a control immunotoxin assay. These results show the in vitro specificity and selectivity of 454A12-rRTA immunotoxin for human gastrointestinal and pancreatic cancer cell lines.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Neoplasias del Colon/tratamiento farmacológico , Inmunotoxinas/uso terapéutico , Neoplasias Pancreáticas/tratamiento farmacológico , Receptores de Transferrina/inmunología , Proteínas Recombinantes/uso terapéutico , Ricina/uso terapéutico , Anticuerpos Monoclonales , Sinergismo Farmacológico , Humanos , Monensina , Células Tumorales Cultivadas
17.
Demography ; 13(2): 259-72, 1976 May.
Artículo en Inglés | MEDLINE | ID: mdl-1278584

RESUMEN

This paper describes a method of estimating life expectancy at birth on the basis of crude vital rates. The method is derived from stable population theory and it furnishes good estimates insofar as the current crude vital rates of a population are close to its intrinsic rates. This condition is generally met in closed populations which have not experienced sharp movements in fertility. The method is useful for estimating life expectancy in developing nations with good sample registration systems but for which information on age is of poor quality. It is also useful for estimating the movement of life expectancy in certain European nations in the period prior to regular census taking. There are a number of nations and regions in Europe for which long series of birth and death rates are available but for which census age counts are widely spaced.


Asunto(s)
Tasa de Natalidad , Esperanza de Vida , Modelos Teóricos , Mortalidad , Femenino , Humanos , Masculino , Matemática , Población
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