Synopsis The slow kinetics of annealing processes in multistranded nucleic acids is spectrophoto-metrically investigated using poly(A)-2poly(U) as a model system. The absorbance changes a t specific wavelengths show that double-helical (A-U) base pairs appear as transient inter-mediates. The annealing process is identified by the enlargement of triple-helical sequences a t the cost of (A-U) bas...

Reserpine depletes tissue catecholamine contents (CAs) in mammals (1, 2) but may (3, 4, 5) or may not (6) affect the CA stores of cold-blooded animals such as the turtle, frog and toad. Doses as high as 50 mg/kg for 3 days failed to decrease toad tissue CAs (6), which were, however, reported to be sensitive to much lower doses if the ambient temperature was high (7). However, no reference to th...

A fast, sensitive, and specific reversed-phase high-performance liquid chromatographic (RP-HPLC) method for the determination of letrozole in Wistar rat serum was developed. In this method, liquid-liquid extraction of letrozole was achieved using diethyl ether as the extracting solvent. The analysis was carried out on a reversed-phase C18 (250 mm × 4.6 mm, 5 μm) column with an isocratic mobile ...

Myoglobin and haemoglobin may frequently be found together in the urine of patients who have suffered from crush injuries. The separation of these two haemo-proteins by differential solubility in salt solutions and their spectroscopic characterization are technically difficult. With this in mind, it appeared worth while to test whether the considerable difference in molecular size of the protei...

Complex formation between [Pd(H2O)4](2+) and oxalate (ox = C2O4(2-)) has been studied spectrophoto-metrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HClO4 ionic medium for the complex formation [Pd(H2O)4](2+) + H2ox ⇄ [Pd(H2O)2(ox)] + 2H3O(+) with equilibrium constant K1,H (in mol dm(-3)) are log10K1,H = 3.38 ±...

Some heavy metals are dangerous to health and there is rising concern about the quality of foodstuffs in some parts of the world. Fish, particularly Tuna fish, can concentrate huge quantities of several metals from water and they even play a significant role in human nourishment. OBJECTIVES: In this study, the concentrations of mercury and four trace metals in five brands of canned tuna samples...

BACKGROUND: Vitamin A which is found in different tissuesand organs plays a particular role in detecting clinical signs invarious deficiency conditions. However, sometimes the marginaldeficiency is present in a way that clinical signs are not visible butperformance defects, such as infertility is seen. OBJECTIVES: Inthis study, the normal baseline levels of vitamin Aand β-carotene inclinically ...

BACKGROUND Restoring carious teeth is one of the major treatment needs of young children. Glass ionomer cement (GIC) systems had become the most important dental restorative and luting materials for use in preschoolers, children and teenagers. Several attempts in developing GIC with antibacterial effects by addition of bactericides, such as chlorhexidine, have been reported. AIM AIM of the st...

Nitrite intoxication occurs frequently in ruminants and equines. The most common treatment of this disorder is administration of 1% methylene blue, although the use of some antioxidant agents e.g. vitamins and complementary treatment may also be useful. The aim of this study was to evaluate the in vitro antioxidative effects of some vitamins on methemoglobinemia induced by sodium nitrite. For t...

some heavy metals are dangerous to health and there is rising concern about the quality of foodstuffs in some parts of the world. fish, particularly tuna fish, can concentrate huge quantities of several metals from water and they even play a significant role in human nourishment. objectives: in this study, the concentrations of mercury and four trace metals in five brands of canned tuna samples...