Short-term effects studies

Using dose-response information from short-term exposure studies to predict the effects of long-term e.xposures, and vice versa... 

Only a few short-term intervention studies have been carried out, principally in postmenopausal women (see Table 6.2). In the first study, the effect of soy... 

For chemicals in general the identification of a potential hazard normally arises from the application of in vitro tests or from short-term toxicity studies undertaken in laboratory animals (up to a period of 90 days in the case of the rat where the test material normally should not exceed 1% of the total diet). This usually enables a critical effect to be assessed. 

Palermo G, Di Gregorio P, Coffa G Effectiveness of the L 105 compound in the treatment of acute diarrhoeal diseases. A short-term controlled study. Med Praxis 1984 5 147-152. 

The period of the test depends on whether long- or short-term effects are of interest. Acute toxicity is the effect of a single exposure or a series of exposures close together in a short period of time. Chronic toxicity is the effect of multiple exposures occurring over a long period of time. Chronic toxicity studies are difficult to perform because of the time involved most toxicological studies are based on acute exposures. The toxicological study can be complicated by latency, an exposure that results in a delayed response. 

Exposure-response data, using short-term biomarkers or surrogate endpoints, can sometimes make further exposure-response studies from clinical endpoints xmnecessary. For example, if it can be shown that the short-term effect does not increase beyond a particular dose or concentration, there may be no reason to explore higher doses or concentrations in the clinical trials. Similarly, short-term exposure-response studies with biomarkers might be used to evaluate early (i.e., first dose) responses seen in clinical trials. 

Only two short-term prospective studies on the effect of soy on the breast have been performed to date. The first reported the effects of two weeks of soy supplementation on the breast of women who were due to have surgery for either benign or malignant breast disease (Hargreaves, 1999). Soy had no adverse effects on any histological index of proliferation. However, a rise of pS2 protein and lowering of apolipoprotein D was observed in the nipple aspirate of women taking soy compared with controls. (A similar effect has... 

Despite the overwhelming evidence for short-term effectiveness, only recently have studies begun to address long-term benefits of stimulant treatments. Prospective randomized controlled trials with durations of 12 to 24 months and doses up to 60 mg/day of MPH have been conducted to address this issue. The largest of these studies, the National Institute of Mental Health (NIMH)-sponsored Multimodal Treatment Study of Attention-Deficit Hyperactivity Disorder (MTA Study), showed that stimulants (either by themselves or in combination with behavioral treatments) lead to stable, long-term improvements in ADHD symptoms as long as the medication is taken (MTA Cooperative Group, 1999). 

Attention deficit hyperactivity disorder (ADHD) is one of the best studied and most effectively treated of all disorders in medicine. The data supporting its validity are more compelling than for many nonpsychiatric medical conditions ( 41, 42). A quarter-century of published treatment studies and clinical experience document the short-term effectiveness of pharmacological management (43). 

The short-term stability study is conducted over extreme environmental conditions to increase the rate of chemical degradation. The data obtained from short-term stability studies are normally used to evaluate longer term chemical effects at nonextreme storage conditions, but they are also helpful to assess the effect of shortterm excursions outside the recommended storage conditions that might occur during shipping. However, the results from short-term stability studies cannot always... 

As in the studies on tea [Duffy et al., 2001], a chronic longer-term vascular response was identified with high-flavanol cocoa, when the flavanol-containing beverage was administered repetitively over several days [Heiss et al., 2007], This effect was clinically characterized as continuously elevated baseline of flow-mediated dilation, on top of which the short-term effect was added on with every new dose this additive effect was at about the same magnitude as without the pretreatment. 

In summary, the evidence for the preventive effect of flavonols in cardiovascular disease is growing based on mechanistic, animal, epidemiological, and short-term intervention studies. However, we must learn from the lessons with dietary antioxidants, the last word awaits large-scale intervention clinical trials. 

Animal studies conducted via the inhalation, oral, and dermal routes of exposure for this duration period would be useful since the potential short-term effects of such exposure as well as effects that could emerge years later, such as cancer, are not known. 

Consequences of the short-term effects of marijuana can greatly influence a teen s future life. Short-term acute effects describe a condition that is temporary and short-lived longterm chronic effects are cumulative and can last a lifetime. Many studies document the acute and chronic health consequences of smoking marijuana. For instance, there are consistent reports that marijuana temporarily impairs short-term memory and learning. This is confirmed by users of marijuana outside the... 

However, equating temporary with benign (harmless) would be misleading because some of marijuana s so-called temporary effects can last a lifetime. For example, studies have shown that driving while high can increase the possibility of a motor vehicle accident. In this case, the consequences of marijuana s short-term effects (impaired attention, motor skills, and reaction times) might quickly transform temporary to permanent. ... 

Rowland A, Grainger R, Smith RS, et al. 1990. Water contamination in North Cornwall A retrospective cohort study into the acute and short-term effects of the aluminum sulphate incident in July 1988. J R Soc Health 110 166-172. 

Short-term dermal studies with 2,3,7,8-TCDD had controversial results. Some studies reported its inhibitory effects on the development of skin tumors in mice otherwise initiated by 13-dimethylbenz-(o)anthracene (Berry et al. 1978, 1979). Others cited its ability to promote tumors initiated by N-methyl-N-nitro-N-nitrosoguanidine (Hebert et al. 1990 Poland et al. 1982). Further, intraperitoneal injection of... 

More recently, studies have applied the probability of extinction as an endpoint to extrapolate short-term effects on long-term population consequences. Based on population viability analysis (Boyce 1992 Groom and Pascual 1997), population size is projected into the future using demographic rates and models that incorporate stochastic effects (Snell and Serra 2000). In practice, it would be difficult to determine extinction rates experimentally due to the need to conduct experiments over multiple generations. Thus, the probability of extinction is typically modeled using the instantaneous rate of increase (Snell and Serra 2000). 

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