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Biomedical subjects

J Arango

Publications and source records attributed to J Arango.

17 recordsLinked to original sources
PubMed2005

Threshold-linear estimation of genetic parameters for farrowing mortality, litter size, and test performance of Large White sows.

Up to 109,447 records of 49,656 Large White sows were used to evaluate the genetic relationship between number of pigs born dead (BD) and number born alive (BA) in first and later parities. Performance data (n = 30,832) for ultrasound backfat (BF) at the end of the test and days to reach 113.5 kg (AD) were used to estimate their relationships with BD and BA at first parity in a four-trait threshold-linear analysis (TL). Effects were year-farm, contemporary group (CG: farm-farrowing year-farrowing month) and animal additive genetic. At first parity, estimates of heritability were 0.09, 0.09, 0.37, and 0.31 for BA, BD, AD, and BF, respectively. The estimate of genetic correlation between BD and litter size was -0.04 (BD-BA). Corresponding values with test traits were both -0.14 (BD-AD, BD-BF). Estimates of genetic correlation between BA and performance traits were 0.08 (BA-AD) and 0.05 (BA-BF). The two test traits were moderately negatively correlated (-0.22). For later parities, a six-trait (BD, BA in three parities) TL model was implemented. The estimates of additive genetic variances and heritability increased with parity for BD and BA. Estimates of heritabilities were: 0.09, 0.10, and 0.11 for BD, and 0.09, 0.12, and 0.12 for BA in parities one to three, respectively. Estimates of genetic correlations between different parities were high (0.91 to 0.96) for BD, and slightly lower (0.74 to 0.95) for BA. Genetic correlations between BD and BA were low and positive (0.02 to 0.17) for BA in Parities 1 and 2, but negative (-0.04 to -0.10) for BA in Parity 3. Selection for increased litter size should have little effect on farrowing piglet mortality. Intense selection for faster growth and increased leanness should increase farrowing piglet mortality of first-parity sows. A repeatability model with a simple correction for the heterogeneity of variances over parities could be implemented to select against farrowing mortality. The genetic components of perinatal piglet mortality are independent of the ones for litter size in the first parity, and they show an undesirable, but not strong, genetic association in second parity.

Animals↗
PubMed2005

Estimation of variance components including competitive effects of Large White growing gilts.

Records of on-test ADG of Large White gilts were analyzed to estimate variance components of direct and associative genetic effects. Models included the effects of contemporary group (farm-barn-batch), birth litter, pen group, and direct and associative additive genetic effects. The area of each pen was 14 m2. The additive genetic variance was a function of the number of competitors in a group, the additive relationships between the animal performing the record and its pen mates, and the additive relationships between pen mates. To partially account for differences in the number of pen mates, a covariable (qi = 1, 1/n, or 1/n(1/2)) was added to the associative genetic effect. There were 4,946 records from 2,409 litters and 362 pen groups. Pen group size ranged from 12 to 16 gilts. Analyses by REML converged very slowly. A grid search showed that the likelihood function was almost flat when the additive genetic associative effect was fitted. Estimates of direct and associative heritability were 0.15 and 0.03, respectively. Within the BLUPF90 family of programs, the mixed-model equations can be set up directly. For variance component estimation, simple programs (REMLF90 and GIBBSF90) worked without modifications, but more optimized programs did not. Estimates obtained using the three values of qi were similar. With the data structure available for this study and under an environment with relative low competition among animals, accurate estimation of associative genetic effects was not possible. Estimation of competitive effects with large pen size is difficult. The magnitude of competition effects may be larger in commercial populations, where housing is denser and food is limited.

Analysis of Variance↗
PubMed2005

Study of codes of disposal at different parities of Large White sows using a linear censored model.

To study the genetic relationship between three grouped reasons for sow removal (SR) in consecutive parities, accounting for censoring, 13,838 records from Large White sows were analyzed. Data were from seven pure-line farms having, on average, 5.9% unknown SR. Three traits were subjectively defined, each corresponding to a classification of SR (reproductive [RR], nonreproductive [RN], and others [RO]). Records for each trait could take one of five categories, according to parity at removal (0 to 4 or later). A multivariate linear censored model was implemented. The model to estimate (co)variance components and parameters included the effects of year-season, region, contemporary group, and additive genetic effects. The most common SR was related to reproduction (48.5%). Diseases of different origin and cause, old age/parity, and sow death or loss accounted for about 18, 7, and 4% of total culls, respectively. Estimates of variance components showed heterogeneity of additive genetic and residual variances for the three traits. Estimates of heritability were 0.18, 0.13, and 0.15 for RR, RN, and RO, respectively. Genetic correlations between removal codes were high (> or =0.90). Results suggest sizeable additive genetic variances exist for parity at removal and different codes of removal. Different SR reasons seem to operate similarly or as a closely related genetic trait associated with fitness. In particular, RN and RO seem to be genetically indistinguishable. Data structure, definition, and volume are major limitations in studies of sow survival. A multiple-trait censored model is preferred to evaluate reasons of sow disposal. Grouped removal causes seem to be strongly genetically correlated but with heterogeneous variances, suggesting that combining all removal causes and treating the trait as parity at disposal is an alternative approach.

Animal Husbandry↗
PubMed1997

[Sanitary conditions of community dining halls in greater Buenos Aires, Argentina].

Because of the importance of food safety for public health, a study was done to determine the microbiologic quality of foods provided to patrons of community dining halls in greater Buenos Aires, Argentina. The study was descriptive and was conducted in three municipalities with intermediate or high poverty indices; a sample of 52 dining halls was selected randomly from those municipalities. Information was collected from April 1994 through April 1995 by means of surveys, direct observations, and microbiologic analyses of the water and food served. Water and food analysis followed the recommendations of the Argentine Food Code and the International Commission on Microbiologic Specifications for Foods, respectively. The results were interpreted according to the values for cooked foods agreed upon by the Working Group on Food Monitoring. The microbiologic analysis revealed that 28 (54%) of the dining halls had food or water of inadequate quality and 11 (21%) had inadequacies in both. Bacillus cereus was the most commonly found pathogenic bacterium in the food samples analyzed. The factors that were significantly associated with unsatisfactory microbiologic conditions in the food and water were lack of disinfection of the water (P = 0.009), lack of hygiene in the environment (P = 0.03), the presence of rodents and insects (P = 0.05), the supply system for raw materials (P = 0.01), and a relatively small number of users, i.e., fewer than 100 (P = 0.0008). It was concluded that water disinfection and general clean-up of the dining halls were measures that could be put in place by providing education in the areas of hygiene and food handling to supervisors and employees. The results obtained also indicate the need to include a food safety evaluation among the general evaluation criteria for food assistance programs.

Adolescent↗
PubMed1996

International migration and national development.

"In this review, we examine theories, data, and research on the macroeconomic relationship between international migration and national development in all world regions. Earlier reviews have generally been pessimistic about the prospects for economic development as a result of international migration. Until recently, however, theories and data have not recognized the complex, multifaceted, and often indirect ways that international migration can influence the economic status of households, communities, and nations, and they have generally failed to appreciate how these relationships can change over time. When these complexities are incorporated into theoretical models, research designs, and data collection, a more nuanced and far more positive picture emerges. Given a supportive mix of macroeconomic policies and infrastructure, international migration may function as a dynamic force promoting economic growth and national development, so long as it does not bring about the selective emigration of scarce human capital needed for development at home."

Demography↗
PubMed1992

Dynamics of methyl groups in proteins as studied by proton-detected 13C NMR spectroscopy. Application to the leucine residues of staphylococcal nuclease.

This paper describes the application of recently developed nuclear magnetic resonance (NMR) pulse sequences to obtain information about the internal dynamics of isotopically enriched hydrophobic side chains in proteins. The two-dimensional spectra provided by the pulse sequences enable one to make accurate measurements of nuclear Overhauser effects (NOE) and longitudinal (T1) and transverse (T2) relaxation times of enriched methyl carbons in proteins. Herein, these techniques are used to investigate the internal dynamics of the 11 leucine side chains of staphylococcal nuclease (SNase), a small enzyme having Mr = 16.8K, in the absence and presence of ligands thymidine 3',5'-bisphosphate (pdTp) and Ca2+. We report the synthesis of [5,5'-13C2]leucine, the preparation of SNase containing the labeled leucine, the sequential assignment of the leucine methyl carbons and protons in the liganded and unliganded proteins, and the measurement of the 13C T1, T2, and NOE values for the SNase leucine methyl carbons. Analysis of the relaxation parameters using the formalism of Lipari and Szabo shows that the internal motions of the leucine methyl carbons are characterized by effective correlation times tau f (5-80 ps) and tau s (less than 2 ns). The fast motion is identified with the rapid rotation of the methyl group about the C gamma-C delta bond axis, while the slow motion is associated with reorientation of the C gamma-C delta bond axis itself. The mean squared order parameters associated with the latter motion, Ss2, lie in the range 0.34-0.92. The values of Ss2 correlate reasonably well with the temperature factors of the leucine methyl carbons obtained from the crystal structures, but some are smaller than anticipated on the basis of the fact that nearly all leucine methyl carbons are buried and have temperature factors no larger than that of the leucine backbone atoms. Five leucine residues in liganded SNase and eight in unliganded SNase have values of Ss2 less than 0.71. These order parameters correspond to large amplitude motions (angular excursions of 27-67 degrees) of the C gamma-C delta bond axis. These results indicate that, in solution, the internal motions of the leucine side chains of SNase are significantly larger than suggested by the X-ray structures or by qualitative analysis of NOESY spectra. Comparison of Ss2 values obtained from liganded and unliganded SNase reveals a strong correlation between delta Ss2 and distance between the leucine methyl carbon and the ligands.(ABSTRACT TRUNCATED AT 400 WORDS)

Leucine↗
PubMed1988

Comparison of N-acetylglucosaminyltransferase V activities in Rous sarcoma-transformed baby hamster kidney (RS-BHK) and BHK cells.

Recent studies have demonstrated that Rous sarcoma virus-transformed baby hamster kidney (RS-BHK) cells express twofold higher levels of those N-linked oligosaccharides that contain the sequence [GlcNAc-beta(1,6)Man (1,6)] compared to nontransformed parental BHK cells (Pierce and Arango, J. Biol.Chem. 261, 10772 [1986]). We have investigated in RS-BHK and BHK cells the activity of UDP-GlcNAc:alpha-D-mannoside beta(1,6)N-acetylglucosaminyltransferase V, the enzyme that begins the synthesis of the sequence that is increased in the RS-BHK cells. We have measured GnT V activity using UDP-[3H]-GlcNAc and a synthetic oligosaccharide acceptor, GlcNAc beta(1,2)Man alpha(1,6)Man beta-O-(Ch2)8COOCH3, separating the radioactive product by a newly devised reverse-phase chromatographic technique. Assayed under optimal conditions, the specific activity of GnT V is about fourfold higher in RS-BHK sonicates than in BHK sonicates, suggesting that this increase in activity may be the primary mechanism that causes the increase in [GlcNAc beta(1,6)Man] sequences in the RS-BHK cells. The apparent Km values of the enzymes in RS-BHK and BHK cell sonicates for UDP-GlcNAc and the synthetic acceptor are similar, as are the pH optima. These results suggest that the increase in GnT V-specific activity in RS-BHK cells is not caused by the presence in these cells of a GnT V with markedly different kinetic properties.

Acetylglucosamine↗
PubMed1987

Activity of UDP-GlcNAc:alpha-mannoside beta(1,6)N-acetylglucosaminyltransferase (GnT V) in cultured cells using a synthetic trisaccharide acceptor.

N-acetylglucosaminyltransferase V activity has been measured under saturating conditions in the extracts of seven cultured cell lines using as substrates, UDP-[3H]-GlcNAc and a synthetic 8-methoxylcarbonyloctyl trisaccharide. The unreacted sugar-nucleotide and its breakdown products were separated from the radiolabeled tetrasaccharide product by reverse-phase chromatography. Enzyme activity was present in six of the cell lines, which were derived originally from either human, mouse, or hamster tissues, with the highest activity in mouse lymphoma BW5147 cells. The PHAR 2.1 variant cell line, derived from the BW5147 line, expressed no detectable activity.

Animals↗
PubMed1986

Rous sarcoma virus-transformed baby hamster kidney cells express higher levels of asparagine-linked tri- and tetraantennary glycopeptides containing [GlcNAc-beta (1,6)Man-alpha (1,6)Man] and poly-N-acetyllactosamine sequences than baby hamster kidney cells.

The alterations in complex-type N-linked oligosaccharides that can occur when an animal cell line is transformed by two dissimilar viruses were examined by comparing the N-linked oligosaccharides of baby hamster kidney (BHK) cells, metabolically radiolabeled with [2-3H]mannose, to the same class of oligosaccharides from BHK cells separately transformed by Rous sarcoma virus (RS-BHK), an RNA retrovirus, and polyoma virus (PY-BHK), a DNA papovavirus. Based on experiments that utilized serial lectin affinity chromatography, glycosidase digestions, and methylation analyses, both RS-BHK and PY-BHK cells demonstrated a significant increase in the relative amounts of tri- and tetraantennary complex-type N-linked oligosaccharides containing the branching sequence, [GlcNAc-beta(1,6)Man-alpha(1,6)Man], compared to the nontransformed BHK cells. In addition, almost all of the poly-N-acetyllactosamine sequence, [GlcNAc-beta(1,3)-Gal-beta(1,4)], was expressed on the tri- and tetraantennary N-linked oligosaccharides from BHK and RS-BHK cells that contain the sequence, [GlcNAc-beta(1,6)Man-beta(1,6)Man]. The increase in the relative amounts of this latter sequence in the transformed cells, therefore, most likely results in an increase in the amount of poly-N-acetyllactosamine sequence on the N-linked glycopeptides of these cells. The analysis of the degree of sialylation of the complex-type N-linked oligosaccharides from BHK and RS-BHK cells by ion exchange chromatography revealed no apparent differences, and in both of these cell types approximately 3% of the glycopeptide fraction radiolabeled with mannose was recovered in a highly negatively charged fraction that was identified by keratanase digestion to be keratan sulfate.

Acetylglucosamine↗
PubMed1985

Separation of metabolically radiolabeled O-methylmannitols and O-methylfucitol by reverse-phase high-performance liquid chromatography: applications to animal cell oligosaccharide structural analysis.

Reverse-phase high-performance liquid chromatography was utilized to separate efficiently and rapidly a standard mixture of various radiolabeled O-methylated mannitols and O-methylfucitol commonly encountered when vertebrate asparagine-linked oligosaccharides are subjected to permethylation, hydrolysis, and reduction with NaBH4. The following reduced, radioactive O-methylhexitols were resolved: 2,4-, 3,4-, and 3,6-di-O-methylmannitols; 3,4,6-tri-O-methylmannitol, 2,3,4-tri-O-methylfucitol, and 2,3,4,6-tetra-O-methylmannitol. To demonstrate the utility of this separation method in the analysis of metabolically radiolabeled asparagine-linked oligosaccharides, mouse lymphoma BW 5147 cells were metabolically radiolabeled with [2-3H]mannose and their glycopeptides prepared by Pronase digestion and fractionated by serial chromatography on immobilized lectins. Each fraction was subjected to methylation and hydrolysis, the released monosaccharides were reduced, and the radioactive O-methylhexitols were separated by reverse-phase HPLC. The relative amounts of the O-methylhexitols in each glycopeptide fraction analyzed were similar to those values determined by a combination of other separation systems.

Animals↗
PubMed1978

[Dental education oriented to various socioeconomic conditions in Panama].

The current system of instruction in the School of Dentistry of the University of Panama is described. The object of the system is to prepare professional people capable of blending biological, techological, and social principles and applying them in different models of dental care for the solution of individual and collective oral health problems. The students take their clinical training in the metropolitan area (clinics on campus and in Santo Tomás Hospital) in the heavily populated rural area (the community hospital and primary schools), and in the sparsely populated countryside (where they work with teams of three auxiliaries in prevention programs for schoolchildren and programs of care for teachers and lend support to community activities).

Education, Dental↗
PubMedDate not supplied

Organs transplanted from intoxicated donors.

PURPOSE: The purpose of our study was to evaluate short- and long-term results of transplants from cadaver donors who have died of poisoning by various substances. MATERIALS AND METHODS: The actuarial survival rate of organs from intoxicated donors was calculated using the Kaplan-Meier method. RESULTS: Among the 507 donors between January 1998 and December 2002, 5 (0.98%) had a cause of brain death of poisoning, namely, organo-phosphates (n = 2), methanol (n = 1), cyanide (n = 1) and acetylsalicilic acid(n = 1), from whom were procured 10 kidneys, 1 liver, 2 corneas, and 1 set of bones. The follow up for patients receiving solid organs was 15.2 months (range, 0-48 months). At 3 months, 90% of kidneys had normal function. No delayed graft function rejection episodes or major complications were reported in any recipient. None showed evidence of acute or chronic poisoning. Two died, 1 early mortality was due to anesthetic complications and the other at 17 months to an unknown cause. Actuarial kidney survival rates were 90% and 80% at 12 and 24 months, respectively. The liver recipient was well at the end of follow up. CONCLUSION: Using organs of poisoned donors is feasible with comparable graft survival rates to other recipient.

Adolescent↗