Long-term study

Calcium Absorption. Phytates in cereal grains have also been reported to interfere with the absorption of calcium. However, a long-term study indicated a retention of calcium in subjects that consume large amounts of bread made with high extraction of flour (19). 

Administration of 5 ppm barium, the acetate, to mice in the drinking water in a life-time study had no observable effects on longevity, mortality, and body weights, or on the incidence of tumors (53). Long-term studies in rats exposed to Ba " in drinking water containing 5 mg/L, as acetate, or 10—250 mg/L, as chloride, resulted in no measurable toxic effects (47). 

Supplementation with high doses of vitamin K1 (1 mg/day for 14 days) or MK-4 (45 mg/day) resulted in decreased levels of undercarboxylated osteocalcin and increase of bone formation markers and in a significant reduction in bone loss, respectively. Using such high doses, any kind of effects besides vitamin K can not yet be ruled out and have to be further elucidated by long term studies. An overview can be found in a review by Palacios [4]. 

A long-term study of tar on beaches of Bermuda indicated that the amount stranded did not differ significantly between 1971-72 and 1978-79 (34). A subsequent study, however, indicated that a significant decrease occurred between 1978-79 and 1982-83, implying that the quantity of tar in... 

Kristenson H, Ohlin H, Hulten-Nousslin M, et al Identification and intervention of heavy drinking in middle-aged men results and follow-up of 24-60 months of long-term study with randomized controls. Alcohol Clin Exp Res 7 203-209, 1983... 

Reliable lifetime TDI values cannot be derived, since long-term studies at the appropriate doses and in the appropriate species are not available. Medium-term exposure TDIs for the estimation of risk were estimated (as the chlorides) as 0.0012 mg/kg body weight for monomethyltin and dimethyltin based on neurotoxicity, 0.003 mg/kg body weight for dibutyltin based on immunotoxicity, and 0.002 mg/kg body weight for dioctyltin, also based on immunotoxicity. No reliable TDI could be derived for monobutyltin or monooctyltin. 

Brief summaries were available for unpublished long-term studies for some of the organotins under consideration. These showed no carcinogenicity for mixtures of mono- and dimethyltins in rats and mono- or... 

Muggleton, N.G., Smith, A.J., and Scott, E.A.M. et al. (2005). A long term study of the effects of diazinon on steep, the electrocorticogram and cognitive behaviour in common marmosets. Journal of Psychopharmacology 19, 455 66. 

The initial enthusiasm for tacrine and velnacrine, which are the anticholinesterases most studied clinically, has been tempered by the fact that not all patients respond. Most show the peripheral parasympathomimetic effects of cholinesterase inhibition, e.g. dyspepsia and diarrhoea, as well as nausea and vomiting, and about half of the patients develop hepatotoxicity with elevated levels of plasma alanine transaminase. While some peripheral effects can be attenuated with antimuscarinics that do not enter the brain, these add further side-effects and the drop-out rate from such trials is high (<75%) in most long-term studies. Donepezil appears to show less hepatotoxicity but its long-term value remains to be determined. 

Beneficial or adverse effects of phytoestrogens have to be more rigorously evaluated and long-term studies are necessary for most, if not all, diseases in... 

No long-term studies of toxicity or carcinogenicity were undertaken. 

Wilson, Kent Lewis (1970) in a long-term study found that most of the soluble phosphate was eluted from the cement in the first 24 hours. By contrast the rate of elution of zinc remained constant for 160 days, the length of the study. They concluded that long-term erosion took place at the surface of the oxide particles rather than in the matrix. 

McWalter, G. K., El-Kafrawy, A. H. Mitchell, D. F. (1976). Long term study of pulp capping in monkeys with three agents. Journal of the American Dental Association, 93, 105-111. 

Long-term studies at different temperatures with suitable methods for elements and compounds... 

Fig. 2-5 Typical storage design for isochronous measurements — long term study (Lamberty et al. 1998)...

A possible disadvantage could be that a larger number of samples has to be measured within a relatively short period of time. This can however be avoided by freezing-in the status of those samples by short-term storage at the reference temperature until the analysis can be carried out. Another disadvantage may be that the results of the long-term study are only available after two years, which may possibly... 

CoTLQVE E, Harris EK, Williams G (1970) Biological and analytic components of variation in long-term studies of serum constituents in normal subjects. Physiological and medical imph-cations. Clin Chem 16 1028-1032. 

A record of any irrigation schemes (type of system used and amount of water) used during the conduct of the trial must be recorded. Often, fertilizers and maintenance chemicals may be mixed into and delivered with the irrigation water, and, hence, details must be recorded. In the case of long-term studies such as soil dissipation or accumulation studies, additional information about the water being used for irrigation (pH, major ion constituents, etc.) must be recorded. 

Ownership A Access to test site must be guaranteed for the duration of study Owner must agree to grant access to the site for duration of study plus possible time extensions. As a result, sub-leasing of the test site is not preferred. This criterion is extremely important for long-term studies such as field soil accumulation studies... 

Leukotriene modifiers (e.g., zafirlukast and montelukast) have not been adequately evaluated in COPD patients and are not recommended for routine use. Small, short-term studies showed improvement in pulmonary function, dyspnea, and quality of life when leukotriene modifiers were added on to inhaled bronchodilator therapy.27,28 Additional long-term studies are needed to clarify their role. 

Theoretically, the risk of serious GI adverse events should be less than with oral NSAIDs, but long-term studies evaluating these events are lacking.38 Studies comparing topical NSAIDs with other topical products, including counterirritants, are also needed.35 Local cutaneous adverse reactions (e.g., erythema, pruritus, and irritation) occur in 1% to 2% of patients and may be due in part to the vehicle used.38... 

The use of the aerosol route for delivery of antibiotics for pulmonary infections remains controversial. The majority of pediatric studies have been conducted in children with cystic fibrosis. In these patients distribution of the antibiotic to the desired tissue site is impeded because of the viscosity of the sputum in patients with acute exacerbations of their pulmonary infections [91,92], Long-term studies have demonstrated preventive benefits of aerosolized antibiotics in children with cystic fibrosis who are colonizing Pseudomonas aeruginosa in their lungs but are not acutely ill [93,94], Cyclic administration of tobramycin administered by nebulizer has received FDA approval [95],... 

Preclinical drug development also involves animal testing [61]. Data from one rodent species and one nonrodent species are usually collected to determine the absorption, metabolism, and toxicity characteristics of the compound. Both short-term (2 weeks to 3 months) and long-term (up to several years) studies are done. The long-term studies are particularly useful for... 

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