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PubMed1993

Creatinine assay by the fuller's earth procedure or by enzymatic determination is adequate for urine but not plasma of mice.

1. Mouse plasma creatinine measured by fuller's earth (15.1 +/- 0.5(41) microM, mean +/- SE) exceeded the same pools read by HPLC [7.5 +/- 0.2(41); P < 0.001]. 2. For mouse urine, the fuller's earth method (3.26 +/- 0.21 mM) slightly exceeded the HPLC method (2.65 +/- 0.18; P < 0.001) with good correlation (r = 0.915, P < 0.001). 3. An enzymatic method (creatinine PAP, Boehringer-Mannheim Diagnostics) for plasma creatinine (5.2 +/- 0.3 microM) was equivalent to HPLC (6.1 +/- 0.1, NS) but with poor correlation (r = 0.23, NS). 4. Creatinine in the urine agreed closely between HPLC (2.84 +/- 0.12 mM) and the enzymatic procedure (2.95 +/- 0.17, NS) with good correlation (r = 0.845, P < 0.001).

Aluminum Compounds↗
PubMed1988

Manganese complexes and the generation and scavenging of hydroxyl free radicals.

In a wide variety of biological systems non-enzyme complexes of the metals copper (Cu) and iron (Fe) have been shown to enhance oxygen radical damage by increasing the production of an oxidative species generally believed to be the hydroxyl free radical (.OH) via "Fenton" and possibly "Haber-Weiss" type reactions. However, the behavior of the chemically and biologically similar transition metal manganese (Mn) with .OH is unknown. Unlike Fe and Cu, inorganic complexes of Mn are known to exist in high concentrations in certain cells. Three different oxygen free radical generating systems and four .OH detection methods were used to investigate the activity of biologically relevant inorganic Mn complexes. These complexes were compared to compounds reported to scavenge and generate .OH. The direct and indirect effects of Mn on the .OH flux were compared by attempting to distinguish the effects of hydrogen peroxide (H2O2), superoxide (O2-), and .OH through the use of selective scavengers and generators. Mn-EDTA and biologically relevant Mn-pyrophosphates and polyphosphates, in contrast to Fe-EDTA, do not generate .OH in these systems. The results suggest that Mn in various forms does, indeed, inhibit oxy-radical damage mediated by .OH, but only if the .OH production is dependent on the presence of O2- or H2O2. Thus, with .OH, as with O2- and H2O2, Mn complexes appear to behave in a fundamentally different fashion from Cu and Fe.

Ascorbic Acid↗
PubMed1993

Adsorbents as antiendotoxin agents in experimental colitis.

The intestinal mucosa protects the body from a large reservoir of intraluminal pathogenic bacteria and endotoxins. This mucosal barrier is disrupted by the inflammation and ulceration of inflammatory bowel disease and may permit the absorption of toxic bacterial products. Systemic endotoxaemia has been demonstrated in ulcerative colitis and Crohn's disease and correlates with the extent and activity of disease. In this study the efficacy of absorbents as antiendotoxin agents in a hapten induced rat model of colitis is investigated. Induction of colitis was associated with systemic endotoxaemia. Enteral administration of terra fullonica and kaolin, but not of charcoal, significantly reduced systemic endotoxaemia (terra fullonica 4.2 (1.40) pg/ml; kaolin 5.29 (1.86) pg/ml; charcoal 32.7 (16.6) pg/ml; water 39.8 (12.6) pg/ml). Data expressed as mean (SE). With increasing severity of colitis, there was a decreasing ability of adsorbent therapy (terra fullonica) to control systemic endotoxaemia. Enteral administration of adsorbents controls gut derived systemic endotoxaemia in experimental colitis in animals and may be a useful antiendotoxin treatment in patients with inflammatory bowel disease.

Adsorption↗
PubMed1993

Characterization of antacid compounds containing both aluminum and magnesium. I. Crystalline powders.

The composition and antacid properties of 10 samples of crystalline antacids containing both aluminum and magnesium were determined. The composition was found to vary significantly, even within the same type of antacid. For example, three of four hydrotalcite samples exhibit evidence of the presence of a minor phase of amorphous aluminum hydroxide. Almagate and almagcit, which are claimed to be unique compounds, were found to be composed of hydrotalcite, magnesium hydroxycarbonate, and/or magnesium carbonate and amorphous aluminum hydroxide. All three magaldrate samples examined contained a minor phase of amorphous aluminum hydroxide. All 10 samples passed the preliminary antacid test and had high acid neutralizing capacities. However, the rate of acid neutralization varied between samples. In some cases the rate of acid neutralization at a dose of 400 mg was too slow to raise the pH to 3.0 as required by the Rossett-Rice test.

Aluminum↗
PubMed1987

Effects of a magnesium-free dialysate on magnesium metabolism during continuous ambulatory peritoneal dialysis.

While the use of magnesium-containing compounds is usually contraindicated in dialysis patients, the risk of toxicity from hypermagnesemia can be reduced by lowering the magnesium concentration in dialysate. We examined the effects of a magnesium-free dialysate on both serum magnesium level and the peritoneal removal rate of magnesium over 12 weeks in 25 stable patients undergoing continuous ambulatory peritoneal dialysis (CAPD). After 2 weeks, the serum magnesium level decreased from 2.2 to 1.9 mg/dL (0.9 to 0.8 mmol/L) (P less than .02) and the peritoneal removal rate increased from 66 to 83 mg/d (2.8 to 3.5 mmol/d) (P less than .05), with both values remaining stable thereafter. There was a strong association between these parameters (r = -0.62, P less than .05), suggesting that the serum magnesium level decreased as a result of the initial increased peritoneal removal rate. For an additional 4-week period, a subgroup of nine patients received magnesium-containing, phosphate binding agents instead of those containing only aluminum. During this phase, serum inorganic phosphorus was well controlled. The serum magnesium level increased only from 1.8 to 2.5 mg/dL (0.7 to 1.0 mmol/L) (P less than .05), due in great part to the concomitant 41% rise in peritoneal magnesium removal from 91 to 128 mg/d (3.8 to 5.3 mmol/d) (P less than .05). No toxicity was noted during the entire 16-week study period, nor did serum calcium change. Thus, serum magnesium levels remained within an acceptable range as magnesium-containing phosphate binders were given through the use of magnesium-free peritoneal dialysate.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum Hydroxide↗
PubMed1982

Successful treatment of paraquat poisoning: activated charcoal per os and "continuous hemoperfusion".

Ingestion of paraquat results in an extremely dangerous poisoning. The first aim is to clear the gastrointestinal tract by inducing emesis and performing gastric/gut lavage; as much activated charcoal as possible should be administered per os and as quickly as possible. The best measure to eliminate paraquat from blood and tissue is hemoperfusion with coated activated charcoal; it has to be performed in the sense of "continuous hemoperfusion" about 8 h/d over a period of 2-3 weeks. These measures give a chance to lower the lethality of paraquat poisoning.

Adolescent↗
PubMed1981

Paraquat poisoning - management and prognosis.

Paraquat poisoning has become a significant clinical problem since the early 1960s. Its high mortality has posed a major challenge to clinicians treating these patients. Two patients who survived and one who did not are reported. The management of these patients and the possible factors affecting their outcome are discussed.

Adolescent↗
PubMed2007

Enhancement of relaxivity rates of Gd-DTPA complexes by intercalation into layered double hydroxide nanoparticles.

In this paper we report the preparation and characterization of [Gd(dtpa)](2-) intercalated layered double hydroxide (LDH) nanomaterials. [Gd(dtpa)](2-) (gadolinium(III) diethylene triamine pentaacetate) was transferred into LDH by anionic exchange. The intercalation of [Gd(dtpa)](2-) into LDH was confirmed by X-ray diffraction for the new phase with the interlayer spacing of 3.5-4.0 nm and by FTIR for the characteristic vibration peaks of [Gd(dtpa)](2-). The morphology of the nanoparticles was influenced by the extent of [Gd(dtpa)](2-) loading, in which the poly-dispersity quality decreased as the [Gd(dtpa)](2-) loading was increased. Compared with the morphology of the original Mg(2)Al-Cl-LDH nanoparticles (hexagonal plate-like sheets of 50-200 nm), the modified LDH-Gd(dtpa) nanoparticles are bar-like with a width of 30-60 nm and a length of 50-150 nm. LDH-Gd(dtpa) was expected to have an increased water proton magnetic resonance relaxivity due to the intercalation of [Gd(dtpa)](2-) into the LDH interlayer that led to slower molecular anisotropic tumbling compared with free [Gd(dtpa)](2-) in solution. Indeed, LDH-nanoparticle suspension containing approximately 1.6 mM [Gd(dtpa)](2-) exhibits a longitudinal proton relaxivity r(1) of approximately 16 mM(-1) s(-1) and a transverse proton relaxivity r(2) of approximately 50 mM(-1) s(-1) at room temperature and a magnetic field of 190 MHz, which represents an enhancement four times (r(1)) and 12 times (r(2)) that of free [Gd(dtpa)](2-) in solution under the same reaction conditions. We have thus tailored LDH-nanoparticles into a novel contrast agent with strong relaxivity, promising for great potential applications in magnetic resonance imaging.

Aluminum Chloride↗
PubMed1983

Novel composite sorbent beads for paraquat removal by hemoperfusion.

The present report describes the development and performance of a column that is to be used for removal of paraquat from circulating blood in a hemoperfusion-type set-up. The key element of the system is a newly developed sorbent material containing fuller's earth entrapped in cross-linked agarose beads (Talosit). The technique produces a sorbent material exhibiting a very large active surface area while allowing for high mobility of paraquat molecules within the beads and favorable flow characteristics of packed column. Cross-linking of the agarose (by epichlorohydrin) also has a most beneficial effect on the mechanical strength of the beads as well as on their stability to sterilization in an autoclave. The composite beads exhibit good blood compatibility. A scanning electron microscope analysis of the beads showed no adherence of cellular blood components after contact with blood. Moreover, no significant changes in plasma composition had taken place when the beads were properly conditioned prior to contact with fresh human blood. A comparative study of paraquat removal from saline solution by the new beads and by cellulose-coated activated charcoal (Adsorba-300C) indicates a higher removal rate with the former. The results obtained so far with this new sorbent are very promising and extension of these studies to in vivo hemoperfusion is under way.

Adsorption↗
PubMed2005

Copper- and magnesium protoporphyrin complexes inhibit oxidative modification of LDL induced by hemin, transition metal ions and tyrosyl radicals.

The oxidative modification of LDL may play an important role in the early events of atherogenesis. Thus the identification of antioxidative compounds may be of therapeutic and prophylactic importance regarding cardiovascular disease. Copper-chlorophyllin (Cu-CHL), a Cu(2+)-protoporphyrin IX complex, has been reported to inhibit lipid oxidation in biological membranes and liposomes. Hemin (Fe(3+)-protoporphyrin IX) has been shown to bind to LDL thereby inducing lipid peroxidation. As Cu-CHL has a similar structure as hemin, one may assume that Cu-CHL may compete with the hemin action on LDL. Therefore, in the present study Cu-CHL and the related compound magnesium-chlorophyllin (Mg-CHL) were examined in their ability to inhibit LDL oxidation initiated by hemin and other LDL oxidizing systems. LDL oxidation by hemin in presence of H(2)O(2) was strongly inhibited by both CHLs. Both chlorophyllins were also capable of effectively inhibiting LDL oxidation initiated by transition metal ions (Cu(2+)), human umbilical vein endothelial cells (HUVEC) and tyrosyl radicals generated by myeloperoxidase (MPO) in presence of H(2)O(2) and tyrosine. Cu- and Mg-CHL showed radical scavenging ability as demonstrated by the diphenylpicrylhydracylradical (DPPH)-radical assay and estimation of phenoxyl radical generated diphenyl (dityrosine) formation. As assessed by ultracentrifugation the chlorophyllins were found to bind to LDL (and HDL) in serum. The present study shows that copper chlorophyllin (Cu-CHL) and its magnesium analog could act as potent antagonists of atherogenic LDL modification induced by various oxidative stimuli. As inhibitory effects of the CHLs were found at concentrations as low as 1 mumol/l, which can be achieved in humans, the results may be physiologically/therapeutically relevant.

Atherosclerosis↗
PubMed2003

A crystallographic study of the binding of 13 metal ions to two related RNA duplexes.

Metal ions, and magnesium in particular, are known to be involved in RNA folding by stabilizing secondary and tertiary structures, and, as cofactors, in RNA enzymatic activity. We have conducted a systematic crystallographic analysis of cation binding to the duplex form of the HIV-1 RNA dimerization initiation site for the subtype-A and -B natural sequences. Eleven ions (K+, Pb2+, Mn2+, Ba2+, Ca2+, Cd2+, Sr2+, Zn2+, Co2+, Au3+ and Pt4+) and two hexammines [Co (NH3)6]3+ and [Ru (NH3)6]3+ were found to bind to the DIS duplex structure. Although the two sequences are very similar, strong differences were found in their cation binding properties. Divalent cations bind almost exclusively, as Mg2+, at 'Hoogsteen' sites of guanine residues, with a cation-dependent affinity for each site. Notably, a given cation can have very different affinities for a priori equivalent sites within the same molecule. Surprisingly, none of the two hexammines used were able to efficiently replace hexahydrated magnesium. Instead, [Co (NH3)4]3+ was seen bound by inner-sphere coordination to the RNA. This raises some questions about the practical use of [Co (NH3)6]3+ as a [Mg (H2O)6]2+ mimetic. Also very unexpected was the binding of the small Au3+ cation exactly between the Watson-Crick sites of a G-C base pair after an obligatory deprotonation of N1 of the guanine base. This extensive study of metal ion binding using X-ray crystallography significantly enriches our knowledge on the binding of middleweight or heavy metal ions to RNA, particularly compared with magnesium.

Base Sequence↗
PubMed2000

Current medical management of secondary hyperparathyroidism.

The treatment of secondary hyperparathyroidism (HPT) in patients with chronic renal disease has improved markedly in recent years. The skeletal pain, disabling fractures, tendon ruptures, and myriad other symptoms associated with HPT can now be avoided, and the quality of life of patients with end-stage renal disease is improved. Control of hyperphosphatemia, maintenance of normocalcemia, and appropriate dosing of vitamin D analogues can prevent HPT in many cases. Palatable, nutritious diets should be followed; serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone should be monitored; and treatment regimens should be adjusted accordingly. If prevention fails, and even if severe HPT develops, many of these patients can still be controlled medically with correction of hyperphosphatemia and high doses of intravenous calcitriol. In our experience, only a few patients require surgical parathyroidectomy (usually noncompliant patients or patients whose HPT has been poorly managed from early uremia). The essence to medical management is to correct the two most important pathogenetic factors of HPT, hyperphosphatemia, and calcitriol deficiency. We present the current approach to the management of HPT, with highlights of recent advances.

Acetates↗
PubMed1990

Adsorption of creatinine to Fuller's earth.

In search for a secondary reference method for the determination of creatinine, the adsorption of creatinine to seven different commercial batches of Fuller's earth have been investigated. Mineralogical investigation of the batches broadly divided them into two subgroups with quite different cation exchange capacities (CEC): dominant smectitic with and without calcium carbonate and dominant palygorskitic with calcium carbonate. Adsorption experiments using 14C-creatinine show, for all Fuller's earth samples, an incomplete adsorption of creatinine. The amount of creatinine adsorbed depends on pH, temperature, concentration of cations as Ca2+ and Na+, and other conditions. Weakly acidic suspensions of Fuller's earth in the course of time change their ability to adsorb creatinine. Compared to a synthetic strong acidic cation exchanger, Fuller's earth is more selective to creatinine. Because of the sensitivity of the adsorption to the various experimental conditions a determination of creatinine in biological fluids using Fuller's earth is too variable. Therefore, we cannot recommend this procedure as a secondary reference method for the determination of creatinine.

Adsorption↗