Selective depression

Nokes reagent 1 complex mixture selective depressant in molybdenite circuits improves molybdenite grade... 

Miscellaneous. In ore flotation, sodium sulfite functions as a selective depressant. In textile processing, sodium sulfite is used as a bleach for wood (qv) and polyamide fibers and as an antichlor after the use of chlorine bleach. Synthetic appHcations of sodium sulfite include production of sodium thiosulfite by addition of sulfur and the introduction of sulfonate groups into dyestuffs and other organic products. Sodium sulfite is useful as a scavenger for formaldehyde in aminoplast—wood compositions, and as a buffer in chrome tanning of leather. 

Many local anesthetics have a selective depressant action on heart muscle when given system cally. This is useful in t.reatment of cardiac arrhythmias, and a 1 idocaine-1 ike drug with this kind of action is tocainide (2). ... 

It has been proposed " that the mechanism(s) of action of gymnemic acids and ziziphins is a biphasic, model-membrane penetration-process. The model suggested that the modifier molecules interact first with the receptor-cell plasma-membrane surface. It was postulated that this initial interaction involves a selective effect on taste perception, including the transduction and quality specification of the sweet stimuli, and selective depression of sweetness perception. Following the initial interaction, the modifier molecules interact with the membrane-lipid interior to produce a general disruption of membrane function and a nonselective effect on taste... 

The answer is e. (Hardman, pp 858-874.) Because verapamil, a Ca channel blocker, has a selective depressing action on AV nodal tissue, it is an ideal drug for both immediate and prophylactic therapy of supraventricular tachycardia (SVT). Nifedipine, another Ca channel blocker, has little effect on SAT Lidocaine and adenosine are parenteral drugs with short ha If-lives and, thus, are not suitable for prophylactic therapy. Procainamide is more suitable for ventricular arrhythmias and has the potential for serious adverse reactions with long-term use. 

Asherson GL, Dieli F. 1992. Immune deviation in the mouse transfer of selective depression of contact sensitivity and interleukin-2 response with retension of interferon-gamma production requires CD8+ T cells. Immunology 76 427-432. 

Isoxsuprine HCl is a p-agonist with a slight selectivity for the P2" adrenoreceptors. However, a considerable portion of the vasodilator actions is attributable to a non-selective depression of vascular smooth muscles. It is considered to be possibly effective in Raynaud s disease, thromboangilitis daliterans, obliterative arteriosclerosis, and cerebrovascular insufficiency. In the management of premature labor, it has been superseded by more selective p-agonists [1]. 

Lidocaine blocks activated and inactivated sodium channels with rapid kinetics (Figure 14-9) the inactivated state block ensures greater effects on cells with long action potentials such as Purkinje and ventricular cells, compared with atrial cells. The rapid kinetics at normal resting potentials result in recovery from block between action potentials and no effect on conduction. The increased inactivation and slower unbinding kinetics result in the selective depression of conduction in depolarized cells. 

A special kind of flotation is froth flotation (124). Selective depressants for the separation of ABS and HIPS have been used. Acetic acid, methanol and quebracho have been probed as selective wetting agents for froth flotation. All these compounds are potentially selective agents, provided the particles are of similar size. The use of quebracho at pH 11 gave the most promising results as selectivity was seen over a wide particle size range. 

Herrero, J. F., Headley, P. M., Parsons, C. G. Mementine selectively depresses NMDA receptor-mediated responses of rat spinal neurones in vivo, Neurosci. Lett. 1994, 165, 37-40. 

The inadvertent activation of a mineral can often result in an undesirable response to flotation. A typical example is quartz, a highly unreactive mineral whose recovery by flotation is therefore difficult. However, in the presence of metal cations, it can be activated to respond to anionic collectors, as shown by the data13 in Figure 3. It is of interest that the pH value at which flotation is effective can be related to that at which the monohydroxy complexes of the metal ions are predominantly stable, suggesting a specific adsorption of these species onto the quartz surface. In some cases this can be used for the selective depression of the quartz minerals in, for example, the flotation of pyrite in the presence of cationic collectors such as the long-chain amines. 

In the unanesthetized dog, reserpine selectively depresses the sympathetic centers and induces facilitation of the parasympathetic centers in the diencephalon. The latter effect accounts for the bradycardia, miosis, aggravation of bronchial asthma, renal and biliary colic, and ulcerative colitis observed in some patients receiving the drug. 

Ault B, Evans RH, Francis AA, et al. 1980. Selective depression of excitatory amino-acid induced depolarizations by magnesium ions in isolated spinal cord preparations. J Physiol 307 413-428. 

Cimetidine crosses the blood-brain barrier and can cause confusion, particularly in elderly or sick individuals with compromised hepatic or renal function, and especially after intravenous treatment. Very rarely an acute confu-sional psychosis has been seen in a younger person (161). Delirium has been thought to be a particular problem with intravenous use, but this is more likely to be a reflection of patient selection. Depression has occasionally been attributed to cimetidine (162,163). 

Ethanol is a central nervous system (CNS) depressant that initially and selectively depresses some of the most active portions of the brain (reticular activity system and cortex). The mechanism of action most likely involves interference with ion transport at the axonal cell membrane rather than at the synapse, similar to the action of other anesthetic agents. Ethanol can bind directly to the gamma-aminobutyric acid (GABA) receptor in the CNS and cause... 

The toxic component of commercial mouthwash products is ethanol. Ethanol is a central nervous system depressant that selectively depresses the reticular... 

Selective lung damage and necrosis occurred in Clara cells of mice that were administered naphthalene. It produced selective depression of pulmonary monooxygenase activities without accompanying changes in hepatic monooxygenease. A dose-dependent alteration of Clara cells (bronchiolar epithelial cells) was noted. 

Cao CQ, Hong YG, Dray A, Perkins MN (2001) Selective depression of nociceptive responses of dorsal horn neurones by SNC80 in a perfused hindquarter preparation of adult mouse. Neuroscience 107 329-338... 

Cannabinoids may also prove beneficial in the treatment of movement disorders, with CBD causing only selective depression of activity at central and peripheral sites associated with the induction of abnormal movements and... 

Selective flotation of fluorite and barite is usually very difficult using water glass and tannic acid. However, good separation of these minerals has been achieved with the use of lignosulfonate [18]. Lignosulfonate can also selectively depress molybdenite and some rare earth metal minerals. In the reverse flotation of hematite and quartz, lignosulfonate has been used as a depressant of hematite. 

Meprobamate exerts a unique combination of actions on the central nervous system. These actions are so much those that would be theoretically expected of a tranquillizer that it is surprising that they are not produced by other depressants of the nervous system and that meprobamate is not a more powerful psychotropic agent. It weakly stimulates the ascending reticular system and does not depress the cortex (thus the level of consciousness is unimpaired) but it does selectively depress the thalamus and it inhibits artificially evoked seizure discharges in the limbic system (thus reducing emotional tension). Although it is possible to specify the physiological systems on which meprobamate acts, it is not yet possible to translate this information into terms of the neurohumoral systems involved. 

Barbiturates selectively depress transmission in autonomic ganglia and reduce nicotinic excitation by choline esters, an effect that may account for the fall in blood pressure produced by intravenous oxybarbiturates and by severe barbiturate intoxication. At skeletal neuromuscular junctions, the blocking effects of both tubocurarine and decamethonium are enhanced during barbiturate anesthesia. These actions probably result from the capacity of barbiturates at hypnotic or anesthetic concentrations to inhibit the passage of current through nicotinic cholinergic receptors. Several distinct mechanisms appear to be involved and little stereoselectivity is evident. 

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