Dependence versus tolerance

Resistance thermometers are made of a pure metal, such as platinum, nickel, or copper. The electrical resistance of such a material is almost linearly dependent on temperature. Resistance thermometers are stable, having a small drift. A widely used and the best-known resistance probe is the IW-100 probe, which is platinum, having a resistance of 100 ohms at the temperature of 0 °C. Other resistance values for PT probes are available. The resistance versus temperature values as well as tolerances for platinum probes are standardized. The shape and size of a resistance probe can vary considerably, resulting in changes in probe dynamics. 

Another way to conceptualize drug problems is to examine psychological versus physical dependence on a substance. Psychological dependence is defined by beliefs A person thinks he or she needs the substance in order to cope. Physical dependence, on the other hand, is defined by actual physical changes related to drug use that may result in withdrawal symptoms and tolerance. However, to confuse matters, recreational users also may experience tolerance and withdrawal, so it is important to be careful when using these distinctions to define whether a person has a drug problem. 

SCT includes autologous and allogeneic transplants and the choice is dependent on the end result desired as well as the risks and benefits of each procedure. Autologous transplants after immunoablative therapy function on the premise of T-cell suppression versus clonal deletion as a cause of tolerance induction in autoimmunity. 

Shiffman S, Zettler-Segal M, Kassel J, Paty J, Benowitz NL, O Brien G (1992) Nicotine elimination and tolerance in non-dependent cigarette smokers. Psychopharmacology 109 449-456 Singha AK, McCance-Katz EE, Heck SA, Kosten TR, OUveto A (1999) Individual differences in humans responding under a cocaine discrimination procedure discriminators versus nondis-ciiminators. Exper Clin Psychopharmacol 7 391-398 Smith BJ, Bickel WK (1999) The novel-response procedure in humans. Pharmacol Biochem Behav 64 245-250... 

The measurement of TON versus [02]L is a useful tool for studying the oxygen tolerance of oxidation catalyst systems. The oxidation of methanol over a series of noble metal catalyst systems reveals large differences in catalyst stability and TON. Pt catalysts appears to be most stable and active, whereas Pd shows less stability, depending on metal dispersion. Upon oxidation of HMF, all Pd and Pt catalysts show a very good tolerance against oxygen. Pd catalysts are the most active in this case, and here also, metal dispersion plays an important role in rate of reaction. 

In the absence of effective neuroprotective treatment for ischemic stroke, a double-blind, randomized, placebo-controUed trial has been performed in 454 patients in primary care (1). Nimodipine 30 mg/day or placebo was started within 6 hours after the onset of the stroke and continued for 10 days. Nimodipine had no effect on all-cause mortality or dependency in daily life. In patients with ischemic stroke documented by CT scan, nimodipine had a borderline significant adverse effect on outcome. Nimodipine was tolerated as well as placebo (7 versus 8 treatment withdrawals respectively), but the lack of benefit does not support the use of any voltage-sensitive calcium channel blocker in ischemic stroke. 

---