Creatinine permeability

In addition, however, to the expected and nonspecific effect of the reduced muscle mass, there may be, in muscular dystrophy, an inability of the remaining muscles to hold creatine to a normal degree (F4) in Duchenne or fascioscapulohumeral dystrophy, but not in amyotrophic lateral sclerosis, there was a more rapid fall in the specific activity of urinary creatinine after the administration of creatine- C. Dystrophic mouse muscle contains a reduced amount of creatine (F5), and this animal provides a convenient tool for investigating any abnormalities in the handing of creatine by dystrophic muscle. Recent studies by Fitch and Rahmanian (F3) showed that entry of creatine- C into isolated skeletal muscle preparations was accelerated in the dystrophic mouse, thus implying that the low creatine content of the dystrophic muscle is due to a more rapid loss of this compound. From further work (F2), the authors concluded that this is due not to an increased membrane permeability to creatine, but to an impaired exchange between creatine with access to the membrane and creatine in a relatively inaccessible form. 

Meyerhoff and Rechnitz (1976) developed a potentiometric creatinine sensor by inclusion of creatinine iminohydrolase between the gas-permeable membrane of an ammonia electrode and a dialysis membrane. Since the specific activity of the enzyme used was very low, 0.1 U/mg, only 43 mU could be entrapped at the electrode. Therefore the sensor was kinetically controlled and reacted to addition of the enzyme activator tripolyphosphate by an increase in sensitivity from 44 mV to 49 mV per concentration decade and a corresponding decrease of the detection limit. These effects agree with theoretical considerations of reaction-transport coupling. The samples were treated with a cation exchanger to remove endogenous serum ammonia. 

For example, at low and high rates of urine flow, the minimal and maximal values of the may vary from 30% to 60% of the glomerular filtration rate. This occurs because various tubular segments are permeable to urea and allow passive reabsorption to occur under conditions of antidiuresis. The fractional excretion of urea (FE ,pa) is calculated as [(urine urea/ plasma urea)/(urine creatinine/plasma creatinine) x... 

This membrane is designed for a sensor which has a layered structure. The sensor can measure glucose, lactate, urea, and creatinine. The membrane is composed of polymer, surfactant, and hydrophyllic compound. Upon conditioning, the membrane structure includes a system of pores which give the membrane excellent permeability. 

The hydraulic permeability has been reduced by a factor of four, and the membrane resistance for creatinine has increased by a factor of five. The solute measure-... 

Figure 4. Permeability of urea through various ratios of the albumin blended chitosan membranes (from a mixture of urea, uric acid and creatinine).

The use of other proteins, such as gelatin, collagen, etc., to prepare chitosan blended membranes was tried in a 7 3 ratio (chitosan protein) and the results were compared to the standard cellulose membranes. The permeability, as a function of time, of various molecules, such as urea, creatinine, uric acid, glucose and albumin, through such membranes is shown in Figures 13, 14, 15, 16 and 17, respectively. It appears that the protein blended membranes exhibited improved permeability properties with respect to small molecules compared to the standard cellulose membrane or bare chitosan. These protein blended membranes... 

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