ABSTRACT
The All-Russian Research Institute of Medical Polymers has designed the medical gels REPAC, DIAGEL, for ultrasound diagnosis, REPAC-T for ultrasound therapy, ELCON and ELCARD for electrocardiography. REPAC, DIAGEL, and REPAC-T have the least sound damping factor (approximately 10(-3) dB/cm) as compared to other similar gels. REPAC and DIAGEL showed a good performance when they were applied in clinical practice during a year. REPAC-T is the gel that can be used both for ultrasound studies and for ultrasound therapy. Unlike REPAC, it has a longer drying-out time, ensuring a 100% contact between the patient's body and the transducer up to 20 minutes. Other gels have been designed for long-term ECG monitoring, bicycle ergometry, etc. ELCARD and ELCON have conductivities of 0.4-0.6 and 0.6-0.9 ohm/m, respectively.
Subject(s)
Electrocardiography/methods , Gels , Ultrasonic Therapy/methods , Ultrasonography/methodsABSTRACT
Particular features of structure and transport properties of a new Soviet-made hydrate cellulose membrane Ultracell have been studied. The membrane has a structure of a swollen gel with well defined macropores that ensures high effectiveness in convectional transport of substances across the membrane. In view of the above the Ultracell membrane may be used both for conventional hemodialysis and also for hemodialysis with simultaneous or consecutive ultrafiltration aimed at removing the excessive water and metabolites with middle molecular weight.
Subject(s)
Cellulose , Membranes, Artificial , Renal Dialysis/instrumentation , Microscopy, Electron, Scanning , Permeability , Surface PropertiesABSTRACT
A highly selective and sensitive high-performance liquid chromatographic assay employing a thermal energy analyzer as the detector for nitroglycerin and its dinitrate metabolites in human plasma has been developed. Prior to chromatography the method employs a simple one-stage extraction step. Nitroglycerin and its dinitrate metabolites are then chromatographed on a 10-micron nitrile bonded phase column using an internal-external standard method. The nitroglycerin and its 1,2,3-propanetriol-1,3- and -1,2-dinitrate metabolites (glyceryl-1,3- and -1,2-dinitrate) have a retention time of 8.5, 10.5, and 11.5 min, respectively at a flow rate of 2.0 mL/min for a mobile phase of 5% v/v acetone in n-hexane. The limits of sensitivity were 0.05 ng/mL for nitroglycerin and 0.25 ng/mL for the dinitrate metabolites. Linearity of response was observed over the 0.1-2.0-ng/mL range for nitroglycerin and 0.5-10.0-ng/mL range for the dinitrate metabolites. Blood level data from a pilot study with human volunteers in receipt of an oral form of nitroglycerin is presented.
Subject(s)
Nitroglycerin/analogs & derivatives , Nitroglycerin/blood , Chemical Phenomena , Chemistry, Physical , Chromatography, High Pressure Liquid , Humans , Time FactorsABSTRACT
Investigations into the structure, mechanical properties and permeability of the Soviet-made cellophane, cellulose film No 100 and cuprophane have shown the Soviet-made cellophane membrane to be inferior to cuprophane with regard to the strength and permeability of low-molecular metabolites. High strength properties of the cellulose film No 100 go with a much more lower permeability than in the case of cuprophane and cellophane. Sterilization with gamma-irradiation does not have any material effect on the physico-mechanical and functional characteristics of the membranes. Ways and means for improving the strength and permeability of the hydrate-cellulose membranes are outlined.
