Subject(s)
Iron/metabolism , Reticulocytes/metabolism , Transferrin/metabolism , Animals , Hydrogen-Ion Concentration , Iron/blood , Iron Radioisotopes , RatsABSTRACT
A multicentric trial compared the effect of chlorpheniramine maleate with a placebo on the signs and symptoms of the common cold. Two hundred seventy-one patients were domiciled for 48 hours and evaluated during this period and for four days afterwards. Evaluations by both patients and physicians showed that chlorpheniramine maleate was superior to placebo in lessening the degree of symptoms of the common cold. Statistically significant differences were found both on the first day and as late as the seventh day. Significant differences and trends were shown in such measures as total objective score, physicians' evaluation of symptoms. The overall incidence of side effects other than drowsiness did not differ between the treatment groups.
Subject(s)
Chlorpheniramine/therapeutic use , Common Cold/drug therapy , Adolescent , Adult , Female , Humans , Informed Consent , MaleABSTRACT
Rabbit reticulocyte incorporation of iron from rabbit transferrin was independent of transferrin iron saturation but uptake from human transferrin was saturation dependent. Unlike human transferrin, rabbit transferrin does not surrender its iron from any unique preferred iron-binding site and can be described as functionally homogeneic. The two proteins also differ in their acid-base iron-binding properties. One human transferrin iron binding site retains an ability to bind iron at somewhat acid pH but this property is not shared by rabbit transferrin.
Subject(s)
Reticulocytes/metabolism , Transferrin/metabolism , Animals , Binding Sites , Humans , Hydrogen-Ion Concentration , In Vitro Techniques , Iron/metabolism , Kinetics , Rabbits , Species SpecificityABSTRACT
59Fe uptake by rabbit reticulocytes from human transferrin-bound iron was studied by using transferrin solutions (35, 50, 65, 80 and 100% saturated with iron) whose only common characteristic was their content of diferric transferrin. During the early incubation period, 59Fe uptake from each preparation by reticulocytes was identical despite wide variations in amounts of total transferrin, total iron, monoferric transferrin and apotransferrin in solution. During the later phase of incubation, rate of uptake declined and was proportional to each solution's monoferric transferrin content. Uptake was also studied in a comparative experiment which used two identical, partially saturated transferrin preparations, one uniformly 59Fe-labelled and the other tracer-labelled with [59Fe]diferric transferrin. In both experiments, iron uptake by reticulocytes corresponded to utilization of a ferric ion from diferric transferrin before utilization of iron from monoferric transferrin.
Subject(s)
Iron/metabolism , Reticulocytes/metabolism , Transferrin/metabolism , Animals , Ferric Compounds/metabolism , In Vitro Techniques , Protein Binding , RabbitsABSTRACT
Human diferric transferrin was partially labeled with 59Fe at low or neutral pH (chemically labeled) and by replacement of diferric iron previously donated to rabbit reticulocytes (biologically labeled). Reticulocyte 59Fe uptake experiments with chemically labeled preparations indicated that iron bound at near neutral pH was more readily incorporated by reticulocytes than iron bound at low pH. The pH-dependent iron dissociation studies of biologically labeled transferrin solutions indicated that Fe3+, bound at the site from which the metal was initially utilized by the cells, dissociated between pH 5.8 and 7.4. In contrast, lower pH (5.2--5.8) was required to effect dissociation of iron that has remained bound to the protein after incubation with reticulocytes. These findings suggest that each human transferrin iron-binding site has different acid-base iron-binding properties which could be related to the observed heterogenic rabbit reticulocyte iron-donating properties of human transferrin and identifies that the near neutral iron-binding site initially surrenders its iron to these cells.
Subject(s)
Transferrin , Animals , Binding Sites , Humans , Hydrogen-Ion Concentration , Iron/blood , Kinetics , Macromolecular Substances , Protein Binding , Rabbits , Reticulocytes/metabolism , Transferrin/metabolismABSTRACT
A double-blind crossover study was conducted to evaluate the antitussive effectiveness of diphenhydramine (DPH) in chornic coughs related to bronchitis, at doses of 25 and 50 mg every 4 hr for four doses. Both 25- and 50-mg doses caused a statistically and clinically significant reduction in frequency of coughs, compared to placebo. The most frequently reported side effect was drowsiness, principally at the 50-mg dose level. There was little or no apparent correlation between antitussive effectiveness and incidence of drowsiness, however, suggesting that the two effects were pharmacologically unrelated.
Subject(s)
Antitussive Agents/therapeutic use , Cough/drug therapy , Diphenhydramine/therapeutic use , Adult , Aged , Chronic Disease , Clinical Trials as Topic , Cough/etiology , Diphenhydramine/adverse effects , Female , Humans , Male , Middle Aged , Smoking/complications , Time FactorsABSTRACT
Despite the remarkable molecular similarity of human lactoferrin and human transferrin, the results of this investigation indicate that human lactoferrin was unable to furnish rabbit reticulocytes with iron for heme synthesis. Although conalbumin closely resembles transferrin in many of its properties, conalbumin iron-binding differs from human transferrin iron-binding. There are conflicting reports in the literature regarding conalbumin's ability to furnish iron to reticulocytes. In this study, small amounts of lactoferrin or conalbumin were adsorbed to mature and immature cell surfaces but neither of these iron-binding proteins surrendered iron intracellularly to reticulocytes for heme synthesis.
