Orally Ingested Microencapsulated Urease and an Adsorbent, Zirconium Phosphate, to Remove Urea in Kidney Failure

1987 ◽  
Vol 10 (4) ◽  
pp. 269-274 ◽  
Author(s):  
E.A. Wolfe ◽  
T.M.S. Chang
Keyword(s):  
Renal Function ◽  
Zirconium Phosphate ◽  
Intestinal Tract ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
Dialysis Therapy ◽  
Dialysis Treatment ◽  
In Series ◽  
Removal System

Dialysis is the conventional treatment for chronic renal failure. It is cumbersome, expensive and time-consuming and thus alternate treatments have long been sought. A compact system consisting of haemoperfusion in series with ultrafiltration can nearly replace dialysis. A urea removal system is the only step required to complete this approach. The potential of combining a microencapsulated enzyme, urease, with an ammonium ion adsorbent, zirconium phosphate, to remove urea was examined in vitro. Urease converts urea to ammonium ions which are then adsorbed on-to zirconium phosphate. This combination would be most effective in the intestinal tract. The capacity of zirconium phosphate is probably not enough to effect the removal of enough urea to completely replace dialysis in patients with no renal function. However, this system could potentially 1) delay the onset of dialysis therapy in patients who still have some renal function, either alone or in combination with haemoperfusion-ultrafiltration, or 2) reduce dialysis treatment times.

The effect of ammonium on photosynthesis and the pathway of ammonium assimilation in Gymnodinium microadriaticum in vitro and in symbiosis with tridacnid clams and corals

1986 ◽  
Vol 227 (1247) ◽  
pp. 147-159 ◽  
Keyword(s):  
Amino Acids ◽  
Ammonium Assimilation ◽  
Water Soluble ◽  
Ammonium Uptake ◽  
Ammonium Ion ◽  
Ammonium Ions ◽  
Tissue Slices ◽  
Marine Animals ◽  
Symbiotic Algae

The effects of added ammonium ion (10-1000 μM) on photosynthetic 14 CO 2 fixation by tissues slices from the mantle of tridacnid clams, by coral tips, and by isolated zooxanthellae from clam mantle were examined. Ammonium ions stimulated photosynthesis in tissue slices but not in freshly isolated zooxanthellae. When ammonium stimulated 14 CO 2 fixation by coral tips an increase in water-soluble labelled compounds, especially amino acids, was observed. Even though ammonium ions did not stimulate photosynthesis in isolated zooxanthellae from clam mantle, light stimulated ammonium uptake in these cells. Studies with 15 NH + 4 confirmed earlier observations (in zooxanthellae isolated from Hippopus ) of light-stimulated transfer of ammonium from the amido-N of glutamine to the amino-N of glutamate, glutamine and other amino acids. This observation, in isolated zooxanthellae and tissue slices, suggests that the glutamine synthase-glutamate synthetase pathway of ammonium incorporation is light-driven in these systems. The possible significance of these processes during ammonium recycling by symbiotic algae in marine animals is discussed.

ALDOSTERONE STIMULATION IN VITRO

1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller
Keyword(s):  
Ammonium Chloride ◽  
Human Urine ◽  
Incubation Medium ◽  
The Other ◽  
Ammonium Ions ◽  
Response Curves ◽  
Urine Extract ◽  
Similar Dose ◽  
Aldosterone Production

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

Chronic Induction of C-Reactive Protein by Hemodialysis, but Not by Peritoneal Dialysis Therapy

1996 ◽  
Vol 16 (2) ◽  
pp. 158-162 ◽  
Author(s):  
Marion Haubitz ◽  
Reinhard Brunkhorst ◽  
Eike Wrenger ◽  
Peter Froese ◽  
Matthias Schulze ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Renal Insufficiency ◽  
Chronic Renal Insufficiency ◽  
Inflammatory Activity ◽  
C Reactive Protein ◽  
Dialysis Therapy ◽  
Dialysis Treatment ◽  
Reactive Protein ◽  
Before And After ◽  
Patient Groups

Objective Evaluation of the inflammatory activity in patients on chronic peritoneal dialysis (PD) and patients on chronic hemodialysis (HD) in comparison to patients with chronic renal insufficiency without dialysis treatment and healthy volunteers. Design Open, non randomized prospective study. Setting Nephrology Department, including HD and PD therapy in a university hospital. Patients Twenty -four patients on chronic PD, 21 patients on chronic HD therapy using a cuprophan dialyzer, 16 patients with chronic renal insufficiency without dialysis treatment, and 33 healthy volunteers; 8 additional patients before and after initiation of chronic HD therapy. All patients and controls were without infection or immunosuppressive therapy. Main Outcome Measures As a marker of the inflammatory activity in the different patient groups, C-reactive protein (CAP) was measured serially using a sensitive, enzyme-Iinked, immunosorbent assay in order to detect values below the detection limit of standard assays. Results All patient groups had CAP levels higher than the normal controls (p < 0.01). Patients on HD had CAP levels significantly higher than PD patients (p < 0.01) whose levels were comparable to patients without dialysis therapy. Accordingly, longitudinal measurements before and after initiation of chronic HD showed a significant increase in CAP levels after the beginning of HD treatment (p < 0.04). Conclusions The results suggest that induction of the inflammatory activity is lower during PD compared to HD, since stimulation by the dialyzer membrane, dialysate buffer, or bacterial fragments in the dialysate is avoided. This observation might indicate a possible lower risk of long-term complications in patients with PD.

scholarly journals In Vitro Activity and Preclinical Profile of TMC435350, a Potent Hepatitis C Virus Protease Inhibitor

2009 ◽  
Vol 53 (4) ◽  
pp. 1377-1385 ◽  
Author(s):  
Tse-I Lin ◽  
Oliver Lenz ◽  
Gregory Fanning ◽  
Thierry Verbinnen ◽  
Frédéric Delouvroy ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Intestinal Tract ◽  
Pharmacokinetic Profile ◽  
Absolute Bioavailability ◽  
Time Curve ◽  
Biochemical Assays ◽  
Single Oral Administration ◽  
Half Maximal Effective Concentration

ABSTRACT The hepatitis C virus (HCV) NS3/4A serine protease has been explored as a target for the inhibition of viral replication in preclinical models and in HCV-infected patients. TMC435350 is a highly specific and potent inhibitor of NS3/4A protease selected from a series of novel macrocyclic inhibitors. In biochemical assays using NS3/4A proteases of genotypes 1a and 1b, inhibition constants of 0.5 and 0.4 nM, respectively, were determined. TMC435350 inhibited HCV replication in a cellular assay (subgenomic 1b replicon) with a half-maximal effective concentration (EC50) of 8 nM and a selectivity index of 5,875. The compound was synergistic with alpha interferon and an NS5B inhibitor in the replicon model and additive with ribavirin. In rats, TMC435350 was extensively distributed to the liver and intestinal tract (tissue/plasma area under the concentration-time curve ratios of >35), and the absolute bioavailability was 44% after a single oral administration. Compound concentrations detected in both plasma and liver at 8 h postdosing were above the EC99 value measured in the replicon. In conclusion, given the selective and potent in vitro anti-HCV activity, the potential for combination with other anti-HCV agents, and the favorable pharmacokinetic profile, TMC435350 has been selected for clinical development.

scholarly journals Molecular recognition of organic ammonium ions in solution using synthetic receptors

2010 ◽  
Vol 6 ◽  
Author(s):  
Andreas Späth ◽  
Burkhard König
Keyword(s):  
Molecular Recognition ◽  
Hydrophobic Interactions ◽  
Covalent Bond ◽  
Ammonium Ion ◽  
Synthetic Receptors ◽  
Ammonium Ions ◽  
Wide Range ◽  
Covalent Bond Formation ◽  
Reversible Covalent ◽  
Ion Receptors

Ammonium ions are ubiquitous in chemistry and molecular biology. Considerable efforts have been undertaken to develop synthetic receptors for their selective molecular recognition. The type of host compounds for organic ammonium ion binding span a wide range from crown ethers to calixarenes to metal complexes. Typical intermolecular interactions are hydrogen bonds, electrostatic and cation–π interactions, hydrophobic interactions or reversible covalent bond formation. In this review we discuss the different classes of synthetic receptors for organic ammonium ion recognition and illustrate the scope and limitations of each class with selected examples from the recent literature. The molecular recognition of ammonium ions in amino acids is included and the enantioselective binding of chiral ammonium ions by synthetic receptors is also covered. In our conclusion we compare the strengths and weaknesses of the different types of ammonium ion receptors which may help to select the best approach for specific applications.

scholarly journals In vitro activity of allicin combined with two antibiotics on intestinal Shigella

2017 ◽  
Vol 6 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Yuchi Jia ◽  
Xiaomei Wu
Keyword(s):  
Intestinal Tract ◽  
Inhibitory Concentration ◽  
Synergistic Effects ◽  
Antagonistic Effect ◽  
Additive Effects ◽  
In Vitro Activity ◽  
Antibacterial Effects ◽  
Combined Application ◽  
Combined Use

Abstract Objective We aimed to evaluate the combined antibacterial effects of allicin in combination with levofloxacin and ceftriaxone on Shigella isolated from the intestinal tract in vitro. Materials and Methods Using a checkerboard design, broth microdilution assay was used to test the effects of the compounds on the organism. We also determined the MIC of the two groups of antibacterial drugs against 30 strains of Shigella and calculated the fractional inhibitory concentration (FIC) index, to judge the combination effect. Result After the combined application of allicin and ceftriaxone the MIC decreased significantly. Distribution of the FIC index was as follows: FIC ≤0.5, accounting for 10%; 0.5< FIC ≤1.0, accounting for 60%; 1 < FIC ≤2, accounting for 30%; FIC >2, percentage is zero. After combined application of allicin and levofloxacin, distribution of FIC index was as follows: FIC≤0.5, ratio is zero; 0.5< FIC ≤1, accounting for 56.7%; 1 < FIC ≤2, accounting for 43.3%; FIC >2, ratio is zero. Conclusion After the combined use of ceftriaxone, levofloxacin, and allicin, most of the tests showed synergistic effects and additive effects on Shigella, while some of them showed no correlation and no antagonistic effect.

Stimulation of Aldosterone Production in vitro by Ammonium Ions

Nature ◽  
1965 ◽  
Vol 206 (4979) ◽  
pp. 92-92 ◽  
Author(s):  
JüRG MüLLER
Keyword(s):  
Ammonium Ions ◽  
Aldosterone Production ◽  
Stimulation Of

Experimental Analysis of Pulsatile Flow Through Elastic Collapsible Tubes: Application to Cardiac Assist Device

1990 ◽  
Vol 112 (1) ◽  
pp. 75-79 ◽  
Author(s):  
O. Lichtenstein ◽  
U. Dinnar
Keyword(s):  
Systemic Circulation ◽  
Aortic Pressure ◽  
Assist Device ◽  
Cardiac Assist ◽  
Cardiac Assist Device ◽  
Non Invasive ◽  
Failing Heart ◽  
In Series ◽  
Vitro Analysis

This study presents a simulated analysis of Phased Compression Cardiac Assist Device (PCCAD) and evaluation of its applicability as a non-invasive temporary assist for a failing heart. The new technique is based on the chest pump mechanism for blood flow augmentation during external massage by phased compression of the abdominal and thoracic cavities. A semi-closed hydraulic system to simulate the systemic circulation was constructed; the system includes a left ventricle which functions according to the Starling principle and a pneumatic system which controls the pressures applied to the thoracic and abdominal cavities, in complete synchronization with the beating normal or failing heart. The possibility of manipulating the three pumps in series (venous, heart, and arterial) has been checked, and the principal parameters which effect the efficiency of the PCCAD were evaluated. This in-vitro analysis shows the high potential of a non-invasive temporary cardiac assist device. It points to the necessary measures one has to take in order to achieve good synchronization and to interfere externally with the augmentation of cardiac output or with the augmentation of root aortic pressure.

Sign in / Sign up

Export Citation Format

Share Document