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1.
Matern Child Health J ; 5(2): 95-107, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11573844

RESUMEN

OBJECTIVES: As investigators increasingly identify racism as a risk factor for poor health outcomes (with implications for adverse birth outcomes), research efforts must explore individual experiences with and responses to racism. In this study, our aim was to determine how African American college-educated women experience racism that is linked to their identities and roles as African American women (gendered racism). METHODS: Four hundred seventy-four (474) African American women collaborated in an iterative research process that included focus groups, interviews, and the administration of a pilot stress instrument developed from the qualitative data. Analysis of the qualitative and quantitative data from the responses of a subsample of 167 college-educated women was conducted to determine how the women experienced racism as a stressor. RESULTS: The responses of the women and the results from correlational analysis revealed that a felt sense of obligations for protecting children from racism and the racism that African American women encountered in the workplace were significant stressors. Strong associations were found between pilot scale items where the women acknowledged concerns for their abilities to provide for their children's needs and to the women's specific experiences with racism in the workplace (r = 0.408, p < .001). CONCLUSIONS: We hypothesize that the stressors of gendered racism that precede and accompany pregnancy may be risk factors for adverse birth outcomes.


Asunto(s)
Negro o Afroamericano , Escolaridad , Resultado del Embarazo , Prejuicio , Femenino , Humanos , Embarazo , Investigación , Factores de Riesgo , Estados Unidos
2.
Eur J Biochem ; 252(3): 513-9, 1998 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-9546668

RESUMEN

The biosynthesis of C18 polyunsaturated fatty acids has been studied in the fungus Mucor circinelloides. Microsomal membrane preparations contained delta9, delta12 and delta6 desaturase activities. The delta9 desaturase exhibited characteristics similar to those of the animal and yeast delta9 desaturases in being membrane bound and utilising stearoyl-CoA as substrate. Cytochrome b5 (a soluble form lacking the 20-amino-acid hydrophobic C-terminus) stimulated desaturation and was identified as a major cytochrome component of the membranes. A high ferricyanide reductase activity (indicative of NADH:cytochrome b5 reductase activity) coupled to inhibition by cyanide further supported the similarity with the mammalian and yeast enzymes. Time-course studies with radiolabelled oleoyl-CoA showed that the oleate [18:1(9)] was transferred to position sn-2 of phosphatidylcholine (PtdCho) and was desaturated to linoleoyl-PtdCho. Removal of the excess oleoyl-CoA from the membranes prior to addition of reductant confirmed that oleoyl-PtdCho is a substrate for the delta12 desaturase. The entry of oleate at this position of the phospholipid was facilitated by the activity of lyso-PtdCho:acyl-CoA acyltransferase (LPCAT), which readily transferred oleate from oleoyl-CoA to lyso-PtdCho. Desaturation of oleate at the sn-1 position of PtdCho was also demonstrated after the entry of oleate in to the phospholipid by the enzymes of the Kennedy pathway. Thus oleate at sn-1 and sn-2 positions served as substrate for the delta12 desaturase and is consistent with observations in oil seed tissues. LPCAT activity was substantially higher than that observed with lysophosphatidylethanolamine:acyl-CoA acyltransferase (LPEAT) indicating that oleate is less effectively channelled to phosphatidylethanolamine for linoleate synthesis. No desaturation on phosphatidylinositol could be demonstrated. Delta6 desaturase utilised linoleate at the sn-2 position of exogenously supplied PtdCho presented to the membranes in the presence of reductant. Thus, the entry of substrates into PtdCho via LPCAT and the synthesis of linoleate [18:2(9,12)] and gamma-linolenate [18:3(6,9,12)] on this phospholipid is similar to that reported for oil seed membranes.


Asunto(s)
Ácido Graso Desaturasas/metabolismo , Ácidos Grasos Insaturados/biosíntesis , Membranas Intracelulares/metabolismo , Microsomas/metabolismo , Mucor/metabolismo , Acilcoenzima A/metabolismo , Animales , Citocromos b5/metabolismo , Ácidos Grasos Insaturados/análisis , Cobayas , Helianthus/metabolismo , Cinética , Mamíferos , NADH NADPH Oxidorreductasas/metabolismo , Saccharomyces cerevisiae/metabolismo
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