SPECIFIC AIMSAccording to folk wisdom, milk intake improves sleeping or has a calming role, a belief supported by some scientific studies. As caseins contain peptides with physiological roles, we hypothesized that one of their peptides can carry this anxiolytic activity. In this study, ␣ s1 -casein tryptic hydrolysate (␣ s1 -CnTH) was tested in vitro on benzodiazepine (BDZ) receptors and checked in vivo for its anticonvulsant and anxiolytic effects in the rat. PRINCIPAL FINDINGS ␣ s1 -CnTH inhibits pentylenetetrazole (PTZ) -induced seizures in Wistar ratBovine ␣ s1 -CnTH was injected intraperitoneally (i.p.) in a Wistar rat 30 min before an i.p. injection of 60 mg/kg of PTZ to evaluate anticonvulsant activity. Crisis severity parameters, crisis latency, and clonus duration were determined after 45 min observation of behavior. The i.p. injection of 1 mg/kg of ␣ s1 -CnTH reduced crisis severity (PϽ0.02). Other parameters were not significantly different from the control. The i.p. injection of 3 mg/kg of ␣ s1 -CnTH increased crisis latency (PϽ0.005), decreased crisis severity (PϽ0.002), and decreased clonus duration (PϽ0.005) of PTZ-induced seizures. The anticonvulsant action of the ␣ s1 -CnTH was underestimated because of a sensitization of animals to PTZ during successive experiments. ␣ s1 -CnTH displays an anxiolytic activity in the elevated plus maze paradigmElevated plus maze test was used to evaluate the anxiolytic effect of the ␣ s1 -CnTH. Diazepam (1 mg/kg) and ␣ s1 -CnTH (3 mg/kg) enhanced (PϽ0.02) the percentage of entries in the open arms whereas general activity, represented by entries in closed arms, was not modified (Fig. 1). ␣ s1 -CnTH displays an anxiolytic activity in the conditioned defensive burying (CDB) experimentWhen a rat is shocked once through an electrical probe mounted on a wall of a test cage, it returns to the probe and buries it with bedding material from the floor of the cage. This CDB response is reduced by anxiolytic drugs. Some behavioral sequences such as exploratory approaches to the probe and escape movements from the probe are needed to differentiate agonists from partial inverse agonists. Similar to diazepam, the ␣ s1 -CnTH, administrated at 3 mg/kg i.p., decreased the duration of probe burying (PϽ0.005) (Fig. 2). The ratio of the retreats to the approaches decreased in rats treated with ␣ s1 -CnTH or diazepam. The CDB paradigm indicates that the ␣ s1 -CnTH exerts an anxiolytic activity over rats. A peptide (␣-casozepine) of the ␣ s1 -CnTH binds on the BDZ site of the GABA A receptorAffinity for the BDZ site of the GABA A receptor from bovine cerebral cortex membranes was measured in competition with [methyl-3 H]-flunitrazepam. ␣ s1 -CnTH competed with the radioligand for binding on the BDZ site of the GABA A receptor with an IC 50 of 72 1 To read the full text of this article, go to http://www. fasebj.org/cgi/doi/10.1096/fj.00 -0685fje; to cite this article, use FASEB J.
A great number of milk-derived peptides have been shown to exhibit angiotensin converting enzyme (ACE) inhibitory properties and thus potential utility in the regulation of blood pressure. The present work aimed to investigate the effects of 2 milk trypsin hydrolysates from alpha(S1)- and alpha(S2)-casein (CH1 and CH2, respectively) on ACE activity evaluated in human umbilical vein endothelial cells (HUVEC) in vitro, rat aortic tissues ex vivo, and renovascular hypertensive rat in vivo. Incubation of HUVEC and rat aortic tissues with CH1 or CH2 induced a concentration-dependent inhibition of hydrolysis of the ACE substrate hippuryl-histidyl-leucine (HHL), the hydrolysates being much less potent than perindopril (an ACE inhibitor). However, in contrast to perindopril, CH1 and CH2 failed to modify angiotensin I-induced aortic ring vasoconstriction. The HPLC profiles of rat plasma after intragastric administration were variable among individuals but none of the observed peaks corresponded to peptides comprising CH1 or CH2 or to fragments of these peptides. During 4 wk of cardiovascular monitoring, in hydrolysate-fed renovascular hypertensive rats, systolic blood pressure weakly decreased compared with the control group. However, the CH1-fed hypertensive rats exhibited a decrease of heart rate during the nocturnal period of activity. To conclude, our results show that CH1 and CH2 inhibited ACE activity in HUVEC and rat aortic tissue but failed to antagonize the aortic-constricting effects of the natural agonist angiotensin I. Moreover, we demonstrated that CH1, to a greater extent than CH2, can slightly affect cardiovascular parameters although the ingested bioactive peptides could not be detected in the blood.
Milk powdersMilk is extremely perishable, and yet, for a number of reasons, it has to be preserved for later consumption. The removal of water prevents the growth of micro-organisms and facilitates preservation and storage of milk constituents. Spray drying is one of the most convenient techniques for producing milk powders and for stabilising milk constituents. Before spray drying, the milk undergoes several processes (such as heat treatment, cream separation, membrane processes, vacuum evaporation and homogenisation). The chemical, physical, technological, nutritional, functional and microbiological properties of the final products are influenced by a number of factors such as operating conditions, properties of the dairy products and storage conditions. After some economic aspects, the aim of this chapter is to describe the process of spray drying of dairy products (more precisely, those enriched in milk fat) including the vacuum evaporation, the lactose crystallisation and the rehydration and to review the effect of the processes on the physico-chemical properties of the dairy powders.
Lors de la découverte d’un cancer du sein, la qualité du bilan préthérapeutique est essentielle afin d’orienter la décision thérapeutique. L’exploration axillaire est primordiale, car elle évalue l’extension régionale de la maladie, ce qui en fait un des facteurs pronostiques majeurs. Différents examens d’imagerie préopératoires peuvent révéler une atteinte de ces ganglions axillaires. Cependant, l’imagerie de référence reste l’échographie axillaire, qui permet également de guider des prélèvements. Depuis l’étude ACOSOGZ0011, nous sommes face à une désescalade thérapeutique de la chirurgie axillaire. Selon des résultats récents, on constate que la place de l’imagerie axillaire est encore plus importante. Le but de l’échographie est d’éviter un curage en deux temps après un ganglion sentinelle positif lorsque les critères de l’ACOSOG-Z0011 ne sont pas remplis.
Détermination des sucres par chromatographie en phase gazeuse. Applications à la mesure de l'activité de la bêta galactosidase dans les ultra-filtrats de lactosérum et à l'étude de l'évolution du lactose dans les yaourts nature par
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