Indicadores de aprendizaje organizacional en grupos de investigación universitaria / Organizational learning indicators in university research groups

Una preocupación de las instituciones universitarias que asignan recursos para la investigación es cómo medir su resultado, más allá de los productos académicos. El presente trabajo propone el aprendizaje organizacional como un resultado importante del proceso investigativo. A partir de los resultados de la investigación, se proponen indicadores e índices para medir el proceso de aprendizaje y las condiciones facilitadoras de grupos de investigación. El trabajo fue realizado con investigadores de los grupos adscritos al Sistema de Investigaciones de la Universidad del Cauca, en Colombia.

One concern of universities that allocate research resources is how to measure their results beyond academic products. This paper proposes organizational learning as one important result of the research process. From research results, it is proposed that indicators and indexes can measure the learning process and facilitator conditions in research groups. The work was carried out with researchers of groups that are part of the Research System of the University of Cauca, in Colombia.

A novel flow injection chemiluminescence determination of Cr(VI) with Dichlorotris(1,10-phenanthroline)ruthenium(II).

A selective novel reverse flow injection system with chemiluminescence detection (rFI-CL) for the determination of Cr(VI) in presence of Cr(III) with Dichlorotris (1,10-phenanthroline)ruthenium(II), (Ru(phen)(3)Cl(2)), is described in this work. This new method is based on the oxidation capacity of Cr(VI) in H(2)SO(4) media. First, the Ruthenium(II) complex is oxidized to Ruthenium(III) complex by Cr(VI) and afterwards it is reduced to the excited state of the Ruthenium(II) complex by a sodium oxalate solution, emitting light inside the detector. The intensity of chemiluminescence (CL) is proportional to the concentration of Cr(VI) and, under optimum conditions, it can be determined over the range of 3-300 µg L(-1) with a detection limit of 0.9 µg L(-1). The RSD was 8.4% and 1.5% at 5 and 50 µg L(-1), respectively. For the rFI-CL method various analytical parameters were optimized: flow rate (1 mL min(-1)), H(2)SO(4) carrier concentration (20% w/V), Ru(phen)(3)Cl(2) concentration (5mM) and sodium oxalate concentration (0.1M). The effect of Cr(III), Fe(III), Al(III), Cd(II), Zn(II), Hg(II), Pb(II), Ca(II) and Mg(II), was studied. The method is highly sensitive and selective, allowing a fast, on-line determination of Cr(VI) in the presence of Cr(III). Finally, the method was tested in four different water samples (tap, reservoir, well and mineral), with good recovery percentage.

Ansiedad dimensional: Un análisis desde la teoría clásica del formulario autodiligenciado de Zung / Dimensional anxiety: An analysis from the classical theory of the Zung self-rating anxiety scale

Introducción: A pesar del uso extendido del formulario de Zung para ansiedad no se encontraron artículos sobre la invarianza de la prueba. Objetivo: Establecer la invarianza por género del formulario para ansiedad autodiligenciado de Zung desde la Teoría Clásica. Métodos: Muestra no aleaotoria de 336 mujeres y 205 hombres estudiantes de varias universidades colombianas que diligenciaron el formulario. El análisis se realizo con análisis confimatorio de factores. Se investigó la invarianza dimensional, de configuración y métrica. Resultados: Se encontró que las invarianzas dimensional y de configuración se cumplen al demostrarse que el constructo es unidimensional en los 2 géneros, seleccionando los modelos con el Criterio de información Bayesiano y que la carga de los ítems es en general alta. No así la invarianza métrica para la cual debieron eliminarse 9 ítems para lograr invarianza en las cargas. Conclusión: El formulario de Zung presenta invarianzas dimensional, de configuración y métrica con 11 ítems. Salud UIS 2011; 43 (2): 159-166.

Introduction: There is not a published report of the invariance of anxiety Zung test, although is widely used. Objective: To stablish gender invariance of the Zung self-rating anxiety scale using Classical Test Theory. Methods: A non random sample of 336 women and 205 men students from several colombian universities that answered the scale. Confirmatory factor analysis was performed. Dimensional, configurational and metric invariance were investigated. Results: Dimensional and configurational invariance are met because for both genders theres is one dimension, using Bayesian Information Crietria as the model selection strategy, and the loadings are generally high. The metric invariance was obtained after deleting 9 items. Conclusion: Eleven items of The Zung self-rating anxiety scale show dimensional, configurational and metric invariance. Salud UIS 2011; 43 (2): 159-166.

Ageing, health and medication consumption in a sample of academic employees at a Mexican university.

Teachers and researchers are valuable resources of universities. A healthy life style includes appropriate utilization of medicines. In this work we explore health status and medicine consumption among a sample of academic employees over 40 years of age at a Mexican university. We analyzed answers to an on line survey in a random sample of academic employees, 40 years and older who work at the National University of Mexico. The 179 item survey was answered from November 2009 to October 2010, by 240 randomly selected academic employees. A section of the questionnaire was oriented toward health issues. We analyzed reported illness, self-perception of health status and medicine consumption. The bodies systems involved most often among those who report any kind of disease were: circulatory and endocrine and/or metabolic, followed by osteomuscular and digestive. Medicinal agents were consumed in the last two weeks by 52% of respondents. Among these, vitamins were consumed by 28%, drugs for pain by 17%, drugs for high blood pressure by 14%, drugs for high cholesterol by 13%, antibiotics by 8%, drugs for diabetes by 5%, cold medicines by 4%. It is suggested that medicinal drugs may not be consumed in situations in which they are indicated, such as in hypercholesterolemia and possibly in hypertension and diabetes. Others, such as vitamins are frequently utilized. Research and interventions should be directed toward better utilization of medicinal drugs.

A combined study of behavior and Fos expression in limbic structures after re-testing Wistar rats in the elevated plus-maze.

The elevated plus-maze is an animal model used to study anxiety. In a second session, rats show a reduction in the exploratory behavior even when the two sessions are separated by intervals as large as 7 days. The aim of the present study was to investigate whether the reduction in the exploratory behavior is maintained after intervals larger than 7 days. Additionally, we aimed at investigating eventual correlations between behaviors in the plus-maze and activation of limbic structures as measured by Fos protein expression after the second session. Rats were tested for 5 min in the elevated plus-maze and re-tested 3, 9 or 33 days later. Other groups were tested only once. The rat brains were processed for immunohistochemical detection of Fos protein. The results show a decrease in the open arms exploration in the second trial with intervals of 3, 9 and 33 days. The expression of Fos protein in the piriform cortex, septal nucleus and paraventricular hypothalamic nucleus in the groups tested with intervals of 9 and 33 days were statistically different from the other groups. The alterations observed in exploratory behavior in the second session in the plus-maze did not correlate with Fos expression. In conclusion, although the specific test conditions were sufficient to evoke behavioral alterations in exploration in the elevated plus-maze, they were enough to induce significant Fos protein expression in piriform cortex, septal nucleus and thalamic and hypothalamic paraventricular nuclei but not in other areas such as dorsomedial nucleus of the hypothalamus and amygdala nuclei, known to be also active participants in circuits controlling fear and anxiety.

Determination of benzimidazole fungicides in water samples by on-line MISPE-HPLC.

An analytical methodology based on an on-line sample enrichment of water samples by means of an imprinted polymer, and the separation of benzimidazole compounds within a C(18) column by ion-pair reversed-phase liquid chromatography, has been developed. The molecularly imprinted polymer has been synthesized by precipitation polymerization using thiabendazole as template molecule, methacrylic acid as functional monomer, and divinylbenzene as cross-linker. Initial experiments carried out by solid-phase extraction on cartridges demonstrated a clear imprint effect for thiabendazole, as well as the ability of the imprinted polymer to selectively rebind several benzimidazole compounds. The developed methodology has been applied to the quantification of thiabendazole, carbendazim, and benomyl in river, tap, and well water samples within a single analytical run at concentration levels below the legislated maximum concentration levels. In this sense, detection limits of 2.3-5.7 ng.L(-1) have been obtained for the analysis of benzimidazole fungicides in different water matrices. Recoveries obtained for the determination of benzimidazole fungicides in spiked samples ranged from 87% to 95%, with RSD below 5% in all cases.

Emotional arousal enhances declarative memory in patients with Alzheimer's disease.

OBJECTIVE: To verify whether the long-term retention of an emotionally arousing story is stronger than the retention of a neutral story, and the enhancing effects of emotional arousal on declarative memory in Alzheimer's disease (AD) patients. METHOD: Twenty subjects (10 with AD and 10 controls matched for age and educational level) were studied. After the audiovisual presentation (neutral story), the subjects rated the narrative's emotionality. Later, they answered a multiple-choice questionnaire about the stories. Two weeks later, they watched the emotionally arousing story. RESULTS: Subjects who watched the emotionally arousing story assigned a score of emotionality higher than the subjects in the neutral group (P = 0.023). In addition, the participants remembered more details of the arousing story, and had a higher score in the questionnaire (P < 0.001). CONCLUSIONS: We demonstrated that an emotionally arousing content enhances long-term declarative memory in AD. Furthermore, present finding supports the use of this instrument for clinical and research purposes.

Clinical variables related with in-stent restenosis late regression after bare metal coronary stenting

In-stent restenosis (ISR) has an incidence between 20% and 30% using bare metal stents. ISR late regression phenomenon (ISRLR) has been previously described, but clinical variables related with this phenomenon remain unclear. The aim of the study was to identify the variables related with ISRLR. METHODS: We identified from our data base 30 patients between November 1995 and September 2002 that fulfilled the following criteria: 1) Documented ISR at follow-up angiography (CA-1); 2) treated medically; and 3) Referred for a second follow-up angiography (CA-2). at least 3 months after CA-1. ISRLR was defined as a > 0.2 mm increase in MLD between CA-1 and CA-2, calculated as the 2-fold of our inter-observer variability. ISR late progression was defined as a > 0.2 mm decrease in minimum lumen diameter (MLD) between CA-1 and CA-2. RESULTS: At the time of CA-2 only 2 patients (6.7%) had symptoms related with the previously stented vessel. We found a mean MLD of 1.03+/-0.34 mm and 1.54+/-0.48 mm at CA-1 and CA-2 respectively (AMLD = 0.51 +/-0.34 mm; p < 0.001). Twenty four patients (80.0%) had ISRLR. Two variables were related to the presence or absence ISRLR: Current smoking at the time of coronary stenting (70.8% vs 20.0% respectively, p = 0.026) and acute coronary syndrome as clinical indication for coronary stenting (and 83.5% vs 40.0% respectively, p = 0.029). CONCLUSION: ISRLR is a frequent phenomenon in patients with ISR treated medically, probably contributing to the benign long-term clinical outcome that has been previously described in patients with asymptomatic or mildly symptomatic ISR. Current smoking at the time of coronary stenting and acute coronary syndrome as clinical indication for coronary stenting are associated with this phenomenon.

Habitat disturbance and small mammal richness and diversity in an Atlantic rainforest area in southeastern Brazil

Since disturbance is an important ecological factor affecting species diversity in natural environments, the increasing human occupation rate in Brazilian Atlantic rainforest, which supports about 50 percent of Brazil's human population, has resulted in intense habitat degradation and fragmentation. Within this rainforest, animal and plant species have been lost at a high rate, and biological and diversity is presently vulnerable. Various animals community studies along a gradient of environmental disturbances have shown that the highest species diversities occur in habitats with intermediate levels of disturbance frequency and intensity. In the present study, which was carried out in the Atlantic forest of Ilha Grande (23° 11' S and 44° 12' W), an island located on the southern coast of Rio de Janeiro State, southeastern Brazil, we estimated species richness, diversity, and abundance of small mammals in three forest areas having different disturbance levels. This was done, in each of these areas and in an anthropic area that they surround, by establishing trails 200 m long, in which points were marked at 20 m intervals. The work involved a total effort of 4800 trap/nights. We also measured some habitat variables at each site in order to evaluated their disturbance levels. Our data showed that the two most conserved forests had the lower species richness and small mammal diversity, while in the anthropic area wild species were absent. The forest with an intermediary level of disturbance showed higher values for species richness and diversity, with the anthropic area presenting the highest disturbance level.

Os distúrbios são importantes fatores ecológicos afetando a diversidade de espécies em ambientes naturais. Na Floresta Atlântica vive cerca de 50 por cento da população humana do Brasil. A crescente ocupação humana neste ecossistema, resultou em uma intensa degradação e fragmentação do hábitat, tornando vulnerável a sua diversidade biológica e ocasionando uma alta taxa de perda de espécies animais e vegetais. Alguns estudos de comunidades têm demonstrado que ao longo de um gradiente de perturbação ambiental, os maiores valores de diversidade de espécies são encontrados em hábitats com níveis intermediários de frequência e de intensidade de distúrbios. No presente estudo, nós estimamos a riqueza, diversidade e abundância de espécies de pequenos mamíferos em três áreas de Mata Atlântica com diferentes níveis de distúrbio. O estudo foi conduzido na Mata Atlântica da Ilha Grande (23° 11' S e 44° 12' W), uma ilha localizada no Sul do estado do Rio de Janeiro, Sudeste do Brasil. Em cada uma das três áreas de florestas e em uma área antrópica rodeada por estas florestas, nós estabelecemos 10 trilhas paralelas com 200 metros de comprimento (com pontos a cada 20 m de intervalo e pontos adicionais acima do solo), num esforço total de 4800 armadilhas/noite. Nós também medimos algumas variáveis estruturais do hábitat para avaliar o nível de distúrbio em cada área. Nossos dados mostraram que as duas florestas mais conservadas tiveram os mais baixos valores de riqueza e diversidade de espécies e que na área antrópica ocorreu uma perda quase total de espécies silvestres. A floresta com nível intermediário de distúrbio teve os maiores valores de riqueza e diversidade de espécies, considerando a área antrópica como um hábitat sob alto grau de distúrbio.

Habitat disturbance and small mammal richness and diversity in an Atlantic rainforest area in southeastern Brazil

Since disturbance is an important ecological factor affecting species diversity in natural environments, the increasing human occupation rate in Brazilian Atlantic rainforest, which supports about 50% of Brazil's human population, has resulted in intense habitat degradation and fragmentation. Within this rainforest, animal and plant species have been lost at a high rate, and biological and diversity is presently vulnerable. Various animals community studies along a gradient of environmental disturbances have shown that the highest species diversities occur in habitats with intermediate levels of disturbance frequency and intensity. In the present study, which was carried out in the Atlantic forest of Ilha Grande (23° 11' S and 44° 12' W), an island located on the southern coast of Rio de Janeiro State, southeastern Brazil, we estimated species richness, diversity, and abundance of small mammals in three forest areas having different disturbance levels. This was done, in each of these areas and in an anthropic area that they surround, by establishing trails 200 m long, in which points were marked at 20 m intervals. The work involved a total effort of 4800 trap/nights. We also measured some habitat variables at each site in order to evaluated their disturbance levels. Our data showed that the two most conserved forests had the lower species richness and small mammal diversity, while in the anthropic area wild species were absent. The forest with an intermediary level of disturbance showed higher values for species richness and diversity, with the anthropic area presenting the highest disturbance level.

Os distúrbios são importantes fatores ecológicos afetando a diversidade de espécies em ambientes naturais. Na Floresta Atlântica vive cerca de 50% da população humana do Brasil. A crescente ocupação humana neste ecossistema, resultou em uma intensa degradação e fragmentação do hábitat, tornando vulnerável a sua diversidade biológica e ocasionando uma alta taxa de perda de espécies animais e vegetais. Alguns estudos de comunidades têm demonstrado que ao longo de um gradiente de perturbação ambiental, os maiores valores de diversidade de espécies são encontrados em hábitats com níveis intermediários de frequência e de intensidade de distúrbios. No presente estudo, nós estimamos a riqueza, diversidade e abundância de espécies de pequenos mamíferos em três áreas de Mata Atlântica com diferentes níveis de distúrbio. O estudo foi conduzido na Mata Atlântica da Ilha Grande (23° 11' S e 44° 12' W), uma ilha localizada no Sul do estado do Rio de Janeiro, Sudeste do Brasil. Em cada uma das três áreas de florestas e em uma área antrópica rodeada por estas florestas, nós estabelecemos 10 trilhas paralelas com 200 metros de comprimento (com pontos a cada 20 m de intervalo e pontos adicionais acima do solo), num esforço total de 4800 armadilhas/noite. Nós também medimos algumas variáveis estruturais do hábitat para avaliar o nível de distúrbio em cada área. Nossos dados mostraram que as duas florestas mais conservadas tiveram os mais baixos valores de riqueza e diversidade de espécies e que na área antrópica ocorreu uma perda quase total de espécies silvestres. A floresta com nível intermediário de distúrbio teve os maiores valores de riqueza e diversidade de espécies, considerando a área antrópica como um hábitat sob alto grau de distúrbio.

A novel missense mutation, c.584A > C (Y195S), in two unrelated Argentine patients with hypoxanthine-guanine phosphoribosyl-transferase deficiency, neurological variant.

The hypoxanthine-guanine phosphoribosyl-transferase (HPRT) deficiency is an inborn error of purine metabolism, responsible for classic Lesch-Nyhan disease and its neurological and hyperuricemic variants. We report a novel mutation in the HPRT gene, c.584A > C (Y195S), in two unrelated Argentine patients affected with the neurological variant with no HPRT activity in lysed erythrocytes. Using PCR plus DNA sequencing and/or restriction enzyme digestion we were able to confirm the diagnosis and identify new cases and potential carriers.

c-Fos associates with the endoplasmic reticulum and activates phospholipid metabolism.

c-Fos, a transcription factor that constitutes DNA-binding AP-1 complexes, regulates gene expression that promotes long-lasting cellular changes. We show that, in addition to its transcription factor activity, c-Fos regulates the metabolism of phospholipids cytoplasmically by an AP-1-independent activity. Two waves of c-Fos expression that promote subsequent waves of stimulation of 32P-orthophosphate incorporation into phospholipids are evidenced in quiescent cultured fibroblasts induced to re-enter the cell cycle. The first wave of c-Fos expression peaks at 7.5 min and returns to control levels by 15 min. The second wave starts by 30 min and remains elevated at 120 min. In the first wave, the lipids that incorporate 32P are predominantly second-messenger polyphosphoinositides (PIP, PIP2, PIP3); whereas in the second wave, membrane-biogenesis-related lipids (PI, PE, PA), become radioactive. Both waves of phospholipid activation depend on c-Fos expression. It is interesting that a peptide that blocks AP-1 nuclear import does not affect phospholipid activation. Immunocytochemical examination showed c-Fos immunoreactivity associated to the endoplasmic reticulum. We conclude that c-Fos, rapidly induced upon cell stimulation, associates to the endoplasmic reticulum where it first regulates the synthesis/ replenishment of phospholipids required for signal transduction pathways and subsequently regulates enzymes involved in the genesis of new membrane necessary for cell growth.

Effects of emotional reactivity on inhibitory avoidance in the elevated T-maze.

The possibility of the presence of inter-individual emotional differences and the memory performance of rats was examined in the elevated T-maze. Two kinds of aversively motivated behaviors, inhibitory avoidance and escape learning, were measured. Based on the number of trials to achieve a learning criterion, rats were divided into two subgroups with either low or high avoidance reactivity (LAR or HAR, respectively). Retention test avoidance latencies showed that HAR animals had better avoidance memory (Mann-Whitney rank sum test, P = 0.0035). No such differences were found for the escape component of this test. These data suggest that individual emotional differences affect inhibitory avoidance performance, which may help to explain the dispersion of the data observed in other studies using this paradigm.

Effects of emotional reactivity on inhibitory avoidance in the elevated T-maze

The possibility of the presence of inter-individual emotional differences and the memory performance of rats was examined in the elevated T-maze. Two kinds of aversively motivated behaviors, inhibitory avoidance and escape learning, were measured. Based on the number of trials to achieve a learning criterion, rats were divided into two subgroups with either low or high avoidance reactivity (LAR or HAR, respectively). Retention test avoidance latencies showed that HAR animals had better avoidance memory (Mann-Whitney rank sum test, P = 0.0035). No such differences were found for the escape component of this test. These data suggest that individual emotional differences affect inhibitory avoidance performance, which may help to explain the dispersion of the data observed in other studies using this paradigm

Measuring emotional memory in the elevated T-maze using a training-to-criterion procedure.

The elevated T-maze, an ethologically based test, has been used to investigate the effects of anxiolytic drugs on memory and the relationships between neural systems involved in such modulation. This test allows the measurement in the same rat of two kinds of aversively motivated behaviors--inhibitory avoidance and one-way escape. The apparatus consists of three arms of equal dimensions, elevated 50 cm from the floor. One arm is enclosed by walls and stands perpendicular to the two open arms. Placing the rat at the end of the enclosed arm and recording the time to withdraw from this arm during three consecutive trials assesses inhibitory avoidance. Soon afterwards, the rat is placed at the end of one of the open arms and the time to leave this arm recorded as escape response. Three days later memory is assessed by reexposing the rats to the maze. One critical question raised by these studies is whether the anterograde amnesia induced by anxiolytic drugs could be due to insufficient learning during training or to amnesia. The present work investigated whether the introduction of a multitrial training-to-criterion procedure could overcome this question. For this purpose, rats were tested as many times as needed to stay in the enclosed arm continuously for 300 s (avoidance learning to criterion). Results from Experiment 1 showed that rats trained to a learning criterion shows significantly better retention performance. Experiment 2 evaluated the effects of pretraining diazepam (DZP) treatment on this training-to-criterion protocol. The results indicate that DZP did not affect acquisition performance but induced a dose-dependent impairment of the inhibitory avoidance in the memory test. One-way escape (latency to enter the enclosed compartment from the open arms) was not affected by DZP. These results rule out the possibility that the impairment of inhibitory avoidance memory in the elevated T-maze could be due to lack of learning during training, and support the hypothesis that the disruptive effects of DZP are on processes involved in long-term storage of information.

Light affects c-fos expression and phospholipid synthesis in both retinal ganglion cells and photoreceptor cells in an opposite way for each cell type.

Retina photoreceptor and ganglion cells isolated from chicks that in vivo were exposed to light have a different phospholipid labeling capacity than those from chicks in the dark. In the light exposed animals, the phospholipid labeling in the ganglion cells is higher (Delta% 45, p<0.005) than in those maintained in the dark, whereas in the photoreceptor cells, the opposite occurs, that is, the phospholipid labeling is higher in the dark than in light. The light-dark differences for phospholipid labeling correlate with the expression of c-fos: when c-fos expression increases (both in mRNA and in c-Fos protein content), phospholipid labeling increases concomitantly. That is, in ganglion cells, c-fos expression and the phospholipid synthesis is higher in light with respect to dark, whereas in photoreceptor cells, c-fos expression and phospholipid synthesis is higher in dark with respect to light. Moreover, when an oligonucleotide antisense to c-fos is administered intraocularly prior to separating the animals into light and dark, no differences in c-fos expression and, consequently, no differences in phospholipid synthesis are found between animals in light and dark. Taken together, these results point to a novel mechanism by which rapid genomic responses to cell stimulation are converted to longer lasting changes in the cell components.

High-density lipoprotein from hypercholesterolemic animals has peroxidized lipids and oligomeric apolipoprotein A-I: its putative role in atherogenesis.

Oxidized lipoproteins have been involved in the pathogenesis of atherosclerosis and atherosclerotic lesions contain oxidized low density lipoprotein. Conversely, the presence of oxidized high density lipoprotein (HDL) in vivo has not been clearly established. Oxidation of HDL in vitro models produces an increase in peroxidized lipids and the appearance of apolipoprotein A-I (apo A-I) oligomers. We investigated the oxidative status of HDL in an in vivo model: the hypercholesterolemic chicken. The HDLs from control and hyperlipemic animals were analyzed for the content of lipid peroxides employing spectroscopic and fluorescence techniques, for the level of apo A-I oligomerization, and for susceptibility to in vitro oxidation. HDL from hypercholesterolemic chickens was more peroxidized (as detected by fluorescence), had higher amount of oligomeric apo A-I, and was oxidized to a greater extent by uv irradiation than that of control animals. We speculate that apo A-I oligomerization could be a key step in the atheroma formation.

Identification of an endogenous inhibitor of the UDP-N-acetylgalactosamine: GM3, N-acetylgalactosaminyl transferase as apolipoprotein A1.

A previously described inhibitor of the UDP-N-acetylgalactosamine: GM3, N-acetylgalactosaminyltransferase (GalNAc-T) (Quiroga et al., 1, 2), was purified from chicken blood serum by a new procedure. When subjected to SDS-PAGE, two major polypeptides of 27 and 70 kDa were observed. When tested in vitro, only the 27 kDa polypeptide inhibited the GalNAc-T. When added to chick cerebral embryonic neurons in culture, both polypeptides inhibited neuritogenesis. Both the 27 kDa and the 70 kDa fractions were present in the cells at 3 h following their addition to the cultures; both polypeptides had aneuritogenic activity and both inhibited the incorporation of [3H]-galactose into the cell gangliosides modifying their labeling pattern to a similar extent. Sequencing of the amino terminal end of the polypeptides showed that 18 and 9 amino acids from, respectively, the 27 and the 70 kDa polypeptides, were 100% homologues with the corresponding region of chick apolipoprotein Al (apo Al). After addition to cells in culture, no interconversion between the two polypeptides was detected after up to 20 h in culture. A monoclonal antibody that recognizes only the 70 kDa polypeptide, blocks its aneuritogenic effect without modifying that of the 27 kDa fraction. It is concluded that the endogenous inhibitor of GalNAc-T is apo Al.