A new method for sequential extraction of oxytocin and antidiuretic hormone for radioimmunoassay.
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14C-Sucralfate, a basic aluminum salt of 14C-sucrose sulfate, or potassium 14C-sucrose sulfate was administered orally to rats with acetic acid-induced gastric ulcer. The radioactivities representing specific binding of the sucrose sulfate moiety were found significantly higher in ulcer sections of the stomach, with the mean within-animal ulcer/non-ulcer ratio attaining 6, 7, 12 and 2.5, respectively, at 1, 3, 6 and 24 h after 14C-sucralfate administration. Microautoradiography provided direct in vivo evidence for binding of the 14C-sucrose sulfate moiety to exuded proteins resulting in effect in formation of a pepsin-resistant barrier over the surface of an ulcer crater. No comparable findings were obtained in the area of normal mucosa. The administration of 14C-sucralfate was associated with much greater and longer-sustained binding to the ulcer lesion and retention in the stomach and duodenum than simple administration of the soluble potassium salt. These findings not only demonstrate therapeutically significant effects of basic aluminum compoundation but also substantiate likely differences from pepsin inhibitors such as amylopectin sulfate in terms of presence or absence of adhesiveness, local barrier effects, and long duration of actions.
In vitro investigations have shown that the adsorption capacity of activated charcoal ('Kohle-Compretten', 'Ultracarbon', E. Merck, Darmstadt, FRG) is just as high as that of 'Fuller's earth' (Surrey powder, Laporte Industries Ltd., Luton, GB) or 'Bentonite BP W.B. (Steetley Minerals Ltd., Milton Keynes, GB). Fuller's earth ('Fullererde') from another manufacturer has had very poor adsorption properties and is thus not suitable for the treatment of paraquat poisoning. Animal experiments have shown that the curative effect of activated charcoal given 0.5, 1, 2, and 3 h after ingestion of 200 and 300 mg paraquat/kg body weight is equally as good or even better than that of 'Fuller's earth' or 'Bentonite BP W.B' Activated charcoal is a substitute of equal value to these mineral soils.
The effects of magnesium aluminum silicate (MAS) addition on the sorption of bromhexine HCl to polyethylene film in tablets were studied. The addition of MAS prevented the sorption of bromhexine HCl to polyethylene film. In order to investigate the mechanism, the interaction between bromhexine HCl and MAS was studied by the powder X-ray diffraction method. It was observed that bromhexine HCl was preferentially adsorbed to the surface of MAS rather than to polyethylene film. The adsorption was accelerated at high temperature and reduced pressure conditions. The sorption of bromhexine base and bromhexine HCl to packaging material were compared using tablet dosage forms. The sorption of bromhexine base to polyethylene film was greater than that of bromhexine HCl.
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In vivo evaluation of a new hemoperfusion (HP) device for Paraquat detoxification is reported. The key element of the extracorporeal system is a column packed with newly developed composite sorbent beads containing Fullers' Earth (FE) entrapped in crosslinked Agarose. The proposed HP system exhibits very good biocompatibility characteristics when conventional heparinization is supplemented by infusing 0.02 ml per min acid-citrate dextrose (ACD) solution per ml. perfused blood at the inlet to the HP column. No complications or abnormalities were detected in animals which were hemoperfused with the system described. It is suggested that the new device is effective and safe for clinical application.
To determine the influence of the metal coordination sphere on the permeability of the blood-brain barrier (BBB), rats were injected intraperitoneally with aluminum lactate (Al(lact)3), aluminum acetylacetonate (Al(acac)3), aluminum maltolate (Al(malt)3) at pH 7.5, or with physiological saline. Two h after each treatment, [14C]sucrose physiological saline solution was injected in animals, and the radioactivity was measured in 5 brain regions (cerebral cortex, mesencephalon, diencephalon, medulla-pons, cerebellum). Radioactivity was significantly elevated in brains from animals treated with Al(malt)3 (hydrolytically stable and hydrophilic), and with Al(acac)3 (hydrolytically stable and lipophilic) but not with Al(lact)3. Time-course study carried out at 2, 4 and 24 h with different aluminum compounds showed a persistent radioactivity 24 h after treatment only in the brain from animals treated with Al(acac)3. Morin stain localized AlIII only in neurons from animals treated with Al(acac)3. These findings indicate that AlIII alters the BBB function in the rat either permanently or transiently depending on the physiochemical properties of the metal coordination sphere. Implications of these results, in terms of AlIII as a potential toxic factor in humans, are considered and discussed.
PURPOSE: To quantify the effects of the ratio of indomethacin to Neusilin US2 and the processing humidity on the amorphization kinetics, stability and nature of the interaction. MATERIALS AND METHODS: A porcelain jar mill with zirconia balls was used to affect conversion of the physical mixtures (48 g) of indomethacin and Neusilin US2 (in the ratios 1:1 to 1:5) to amorphous states at room temperature (25 degrees C) employing either 0% RH or 75% RH. The percent crystallinity in the samples was determined from ATR-FTIR scans chemometrically. The physical stability of these co-ground amorphous powders was evaluated at 40 degrees C/75% RH and 40 degrees C/0% RH. RESULTS: The lower the ratio of indomethacin to Neusilin US2, the faster is the amorphization during co-grinding. Higher humidity facilitates amorphization with a more pronounced effect at the lower ratio of indomethacin to Neusilin US2. There is further amorphization of some of the partially amorphized samples on storage at 40 degrees C/75% RH for 3 months. Hydrogen bonding and surface interaction between metal ions of Neusilin US2 and indomethacin can explain changes in the FTIR spectra. CONCLUSIONS: The processing humidity and the ratio of indomethacin to Neusilin US2 are important factors to be considered to affect amorphization during ball milling. Amorphous indomethacin can be stabilized by co-grinding with Neusilin US2.
The binding capacity of activated charcoal for paraquat was evaluated in vitro and in vivo and compared with Fuller's earth. In vitro activated charcoal absorbs paraquat and is as effective as Fuller's earth. Activated charcoal's absorbing capacity for paraquat is increased when it is suspended in magnesium citrate and is maximal at pH 7.8. Paraquat (200 mg/kg) administered orally to male mice, followed 30 minutes later by activated charcoal, Fuller's earth (4 gm/kg), and magnesium citrate (0.01 cc/gm) resulted in a survival rate of 31% in the controls, 63% in the activated charcoal and Fuller's earth groups, and 69% in the magnesium citrate group (P values not significant). When activated charcoal was administered concomitantly with magnesium citrate, the survival rate was improved significantly to 94% (P less than 0.01). The efficacy and greater availability of activated charcoal and magnesium citrate make these materials the treatment of choice for gastrointestinal decontamination in oral paraquat poisoning.
In a previous review it was predicted that "the reactivity of five-coordinate complexes would certainly be different than that of the four-coordinate derivatives". Structurally and spectroscopically, there is very little difference in the higher-coordinate compounds when compared to the four-coordinate derivatives. However, the prediction was remarkably accurate, if not a bit understated, for the reactivity of these compounds. There appears to be a tremendous potential in catalysis and synthesis for the five-coordinate derivatives, far more possibilities than exist for the lower-coordinate derivatives. Furthermore, the higher-coordinate derivatives are rarely air or moisture sensitive and, thus, may be handled under a wider range of conditions. Although reactions such as oxirane and lactide polymerizations are fairly well-known now with five- and six-coordinate aluminum compounds, the potential of these compounds has only begun to be developed. It is easy to imagine that these types of compounds will see wider use than the related transition-metal compounds.
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The creep of microspecimens of posterior dental composites was studied using a torsional creep apparatus. Shear stresses were maintained for 3 h and recovery was followed for 50 h. Creep curves were obtained at 21, 37, and 50 degrees C and four torque levels. The effect of conditioning the specimens in water up to 8 weeks was studied. The posterior composites exhibited linear viscoelastic behavior at low deformations. They had higher shear moduli and greater resistance to creep than conventional and microfilled composites. In aging experiments, maximum shear moduli occurred when specimens were 48 h to 1 week old. Subsequent softening was attributed to water absorption. Residual strain was highest when the composites were stressed within 24 h of initiating polymerization. Residual strain was very low in specimens 48 h to 8 weeks of age.