Into milk, transfer

For milk, transfer the entire sample extract into a separatory funnel (250-mL), add an equivalent volume of dichloromethane plus a half equivalent volume of sodium chloride solution (5%, w/v). Shake the separatory funnel for 2 min and allow the phases to separate. Partially fill a glass filter funnel with anhydrous sodium sulfate (approximately 10 g) and filter the lower dichloromethane layer through the sodium sulfate, collecting the filtrate in a round-bottom flask (250-mL). Wash the sodium sulfate with dichloromethane (5 mL) and collect the washings in the same round-bottom flask. Rotary evaporate the sample to dryness under reduced pressure with a water-bath temperature of 40 °C. Dissolve the residue in 4 mL of ethyl acetate-toluene (3 1, v/v) and transfer the solution to a suitable vial ready for GPC cleanup. 

Vreman, K., N.G. van der Veen, E.J. van der Molen, and W.G. de Ruig. 1986. Transfer of cadmium, lead, mercury and arsenic from feed into milk and various tissues of dairy cows chemical and pathological data. Neth. Jour. Agric. Sci. 34 129-144. 

Oo, C.Y., Kuhn, R.J., Desai, N., Wright, C.E., and McNamara, P.J. (1995) Pharmacokinetics in lactating women prediction of alprazolam transfer into milk. Br J Clin Pharmacol 40 231-236. 

Mammary gland size, milk production and release and histology can be affected adversely by toxic agents, and many exogenous chemicals and drugs are transferred into milk (WHO, 1988 American Academy of Pediatrics Committee on Drugs, 1994 Sonawane, 1995 LaKind et al., 2001). 

Transfer coefficients of 0.0002 (kg-day)"1 for uptake into milk and 0.0015 (kg-day) 1 for uptake into beef tissue have been reported (Baes et al. 1984). The transfer coefficients represent the fraction of daily aluminum intake in feed that is transferred to a kilogram of milk or beef muscle. Based upon the above values, aluminum is not transferred to beef muscle or milk from feed to any appreciable extent and therefore would not be expected to bioaccumulate in terrestrial food chains. 

In rodents, placental transfer of CDDs to the fetus is relatively limited, but transfer during sensitive periods of organogenesis is biologically important as evidenced by effects on fetuses or offspring exposed in utero. Excretion into milk represents a major pathway for maternal elimination of CDDs and, therefore, for exposure to offspring. In C57BL/6N mice administered a single oral dose of 30 g 14C-... 

Hagemeister, H., Precht, D., Franzen, M. and Barth, C.A. (1991) Alpha-linoleic acid transfer into milk fat and its elongation by cows. Fett Wissen. Technol., 93, 387—391. 

Relationships between trans-10, cz.y-12 CLA and milk fat synthesis have been examined. There is a curvilinear relationship between the reduction in milk fat yield and the abomasal infusion dose of trans-10, cis-12 CLA (Figure 3.4). Trans-10, cis-12 CLA is a very potent inhibitor of milk fat synthesis in dairy cows a dose of 2.0 g/d (<0.01% of dry matter intake) reduced milk fat synthesis by 20%. Trans-10, cis-12 CLA is also incorporated into milk fat and in this case the relationship is linear (Figure 3.4) a summary of seven studies showed that the transfer efficiency of aboma-sally-infused trans-10, cis-12 CLA into milk fat averaged 22% (de Veth et al., 2004). The linear relationship in transfer to milk fat is remarkable when one considers that the yield of milk fat is simultaneously decreased as the abomasal dose of trans-10, cis-12 CLA is increased. This suggests that the mechanisms which coordinate the CLA-induced decrease in the use of preformed fatty acids for milk fat synthesis have a less pronounced effect on the mammary uptake and incorporation of trans-10, cis-12 CLA into milk fat, but the basis for this difference is unknown. 

Swamp, D., Patra, R.C., Naresh, R. et al. (2005). Blood lead levels in lactating cows reared around polluted localities transfer of lead into milk. Set Total Environ. 347 106-10. 

Finally, lipid-soluble chemicals like the insecticide DDT, polychlorinated biphenyls, and methylmercury are excreted readily as dissolved chemicals into milk fat droplets. Lead is secreted into milk using the same transport system as calcium. Nursing mothers may therefore transfer environmental contaminants to their infants - not to the point, however, of negating the well-established benefits of breastfeeding. 

Eastman DF, Dimenna GP, Segall HJ. Covalent binding of two pyrrolizidine alkaloids, senecionine and seneciphylline, to hepatic macromolecules and their distribution, excretion, and transfer into milk of lactating mice. Drug Metab Dis 1982 10 236-40. 

Also the placenta has a barrier for hydrophilic and very lipophilic compounds, which is comparable to the blood-brain barrier. Correspondingly, quantitative relationships could be derived for the placental transfer ratios TR of various drugs (eq. 170, recalculated) [775]. The diffusion of drugs into milk and prostatic fluid has been reviewed [472, 761]. 

The influence of dietary fat on milk fat composition is complex (Storry, 1981) and results vary considerably (Banks et al., 1976 Bitman etal., 1973 Storry, 1981). Net transfer of acids from the diet into milk are reported for the following acids <12 0 low transfer 12 0, 27% 16 0, 29-90% 18 (total), 19-65% 20-22 (total), low transfer. Some results are given in Table 3.158. The Cig polyunsaturated acids in the diet are hydrogenated in the rumen prior to adsorption. 

Aflatoxin Ml 1 Milk and milk products (cheese) Metabolite of aflatoxin Bl transferred into milk... 

The most important factors affecting the transfer of veterinary drugs from the blood plasma into milk (mammary gland cells) are ... 

In addition to intermediary metabolism of AA between the duodenum and the mammary gland, biologically explaining the decreased efficiency of the transfer of absorbed AA into milk protein (Lapierre et al, 2006b), errors in estimating the supply can also influence the estimates of the utilization MP for milk protein synthesis. Overestimating the increase in the supply of MP would result in rmderestimating the trarrsfer efficiency of MP to milk protein and vice versa. Our meta-... 

Figure 3. Relationship between ME/MP ratio in nutrient supply and transfer efficiency ofMP into milk protein. The ME/MP ratio was estimated by a mixed model regression analysis (random study effect) with a model ME (MJ/d) =MP (kg/d)...

Several studies achieved in enviromnental conditions have shown that PAHs can be excreted in the milk of ruminants when feeded with PAHs [306]. The authors concluded there was an excretion of PAHs into milk under native forms when rumiants were fed with low PAHs content. However, a slight increase in concentration could induce the metabolism, which should lead to an increase in the excretion of metabolites into the milk. In spite of the absence of a significant transfer of parent PAHs to milk, the appearance of metabolites in milk raises questions of their impact on human health. 

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