Inhibitory effect in vitro

Studies on the penicillin. Relation between the growth inhibitory effect in vitro and the protective activity in vivo," H. Umezawa and T. Takeuchi, J. Penicillin, 1 (1947) 14-18 spoken at the Penicillin Committee in Jan., 1945. 

Slater, T.F. (1968). The inhibitory effects in vitro of phenothia-zines and other drugs on lipid-peroxidation systems in rat liver microsomes, and their relationship to the liver necrosis produced by carbon tetrachloride. Biochem. J. 106, 155-160. 

Since the glucose-lysine reaction mixture used in this study consisted of a number of different substances, it was of interest to study whether the observed inhibitory effect in vitro could be attributed to some specific compound(s). In order to obtain a separation, an aliquot of the LMW fraction, radiolabel led by [U- glucose added to the reactants, was applied on a Sephadex G-50 column and eluted with water. The UV absorbance was recorded and the eluate was collected in fractions. The degree of inhibition effected by small samples of equal volume from each fraction and exerted on carboxypeptidase A and purified aminopeptidase N was determined as well as the radioactivity... 

Nicoletti et al. [ 18] investigated the antiviral activity of the green algae Caulerpa taxifolia. The chloroform-methanol residue showed an interesting inhibitory effect in vitro toward the feline immunodeficiency... 

Experiments utilizing isolated superfused and blood perfused cardiac tissue preparations and isolated rat, rabbit, and cat whole hearts all demonstrate the potent, concentration-dependent, negative inotropic activity of the calcium inhibitory compounds (45 50, 90-95, 112, 113, 114, 118, 140, 141). Studies comparing the relative negative inotropic effects of several of the calcium inhibitory compounds indicate that those compounds exhibiting the most potent calcium inhibitory effects in vitro are the most effective in reducing cardiac contractility in vivo (6). Of those compounds most frequently compared, nifedipine and niludipine exhibit the most profound negative inotropic activity followed by verapamil (levo isomer), diltiazem and perhexiline (88, 89-142). 

Thus, among the herhs used to remove dark spots on the skin, some (especially chuan-xiong, fangfeng, gaoben, and danggui) have been shown to exhibit marked tyrosinase inhibitory effects in vitro ... 

Deng and others (1998) studied the effects of Brussels sprouts on spontaneous and induced oxidative DNA damage in terms of 8-oxo-7,8-dihydro-2,-dcoxyguanosinc (8-oxodG) in rats. Kasai and others (2000) demonstrated that various plant extracts, such as carrot, apricot, and prune, showed inhibitory effects in an in vitro assay of lipid peroxide-induced 8-OHdG formation. Zhu and others (2000) investigated the effect of an aqueous extract of cooked Brussels sprouts on formation of 8-oxodG in calf thymus DNA in vitro. 

In vitro Effects. In vitro measurement of the effect of one xenobiotic on the metabolism of another is by far the most common type of investigation of interactions involving inhibition. Although it is the most useful method for the study of inhibitory mechanisms, particularly when purified enzymes are used, it is of limited utility in assessing the toxicological implications for the intact animal. The principal reason for this is that in vitro measurement does not assess the effects of factors that affect absorption, distribution, and prior metabolism, all of which occur before the inhibitory event under consideration. 

Antihypertensive Effects In vitro In vitro, ACE inhibitory activity is generally analyzed using synthetic substrates that have amino-substituted tri and dipeptides of hippuryl-His-Leu (Fahmi et al., 2004 Jung et al., 2006b). 

Chronic treatment with cannabinoids can induce a state of tolerance to their inhibitory effects in the gastrointestinal tract. Studies of this phenomenon have been performed predominantly with pieces of tissue excised from chronically treated animals (ex vivo) or on isolated tissues pretreated in vitro with a cannabinoid receptor agonist. These investigations were comprehensively reviewed by Pertwee (2001) and will be summarised here. 

Another series of inhibitors of sterol metaboUsm in insects were synthesized by our group. These are 24,28-iminofucosterol (104) [176], stigmasta-5,24(28),28-trien-3)8-ol (105) [177], and cholesta-5,23,24-trien-3(j8-ol (106) [177] (Fig. 19). When the imine (104) or the allene (105) was administered in the silkworm diet in combination with sitosterol or cholesterol, the growth and development of B. mori were markedly retarded. The imine was expected to inhibit the conversion of fucosterol epoxide to desmosterol, and this was verified by in vitro experiments where the imine, at the same level as the substrate [ H]fucosterol epoxide (92), completely blocked the transformation into desmosterol. However, the imine may not exert its effect solely by limitation of desmosterol or cholesterol formation because cholesterol as the sole dietary sterol was unable to prevent the inhibitory effect. In contrast, the allene (106) seemed to exert little effect on sitosterol dealkylation because the sterols in silkworms fed on the allene (106) in combination with sitosterol were essentially the same as in controls. 

The effect of -substitution on TS-inhibitory potency in vitro has been examined in detail [169]. Of the 13 representative compounds tested, only two, the V -ethyl (IV.293) and 2V" -(2-fluoroethyl) (IV.296) analogues had IC50 values that were < 5-fold greater than the IC50 of CB3717. The IC50... 

Andalusol also showed remarkable immunomodulating properties [129]. It exhibited a dose-dependent inhibitory effect on the haemolytic activity of the classical complement pathway, and also inhibited lymphocyte proliferation induced by concanavalin at non-cytotoxic concentrations. No effect on the alternative pathway was observed. Therefore, andalusol has immunosuppressive effects in vitro. 

S-Nitrosoalbumin manifests a variety of novel effects that arise as a consequence of its S-nitrosation. In addition to its vasodilatory and platelet-inhibitory properties in vitro (Stamler et al., 1992c), administration of this... 

Depending on concentration, herbicides may inhibit many different plant metabolic pathways in vitro as well as in vivo. However, often the relevance of an inhibitory activity in vitro for the action on the intact growing plant is not clear. Trifluralin and chlorpropham e.g. affect chloroplast and mitochondrial activities in vitro (J ). In the field, however, they inhibit the growth of seedlings and provoke characteristic morphological responses which can not be traced to the effects on the organelles mentioned above. A simple test system more closely reflecting the primary sensitive pathway under field conditions would therefore clearly be helpful. 

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