Poly (triethylenglycol monomethacrylate) and poly (glycerol monomethacrylate) cross-linked gel as potential viscoelastics for intraoperative use.

BACKGROUND: The highly swelling poly (glycerol monomethacrylate) gel (polyGLYMA) and hydrophilic polymer poly (triethylenglycol monomethacrylate (polyTEGMA) were tested as potential viscoelastics for intraoperative use in anterior segment surgery. METHODS: PolyGLYMA was implanted into the anterior chamber in 5 rabbits, and 40% polyTEGMA in 16 rabbits. The eyes were enucleated 1 week to 3 months after the operation. The corneal endothelium was examined with specular microscopy, and then the whole eye histopathologically. RESULTS: In all eyes of the polyGLYMA group, the clinical findings were characterized by a marked ciliary injection and severe secondary glaucoma, and the histologic ones by a marked inflammatory infiltration and thickening of Descemet's membrane in the anterior chamber angle. Specular microscopy revealed a decrease in the endothelial cell density and polymorphism of the endothelial cells. In the polyTEGMA group, the anterior segment and the fundus were physiologic all the time, and specular microscopy and histologic findings showed no degenerative and/or inflammatory changes. CONCLUSIONS: PolyGLYMA proved unsuitable for intracameral application in rabbits. The new polymer polyTEGMA is characterized by high biologic tolerance after its implantation into the anterior chamber of rabbits. PolyTEGMA 40% might be considered as a potential viscoelastic material in humans.

Use of hemoperfusion in experimental intoxication with nerve agents.

The aim of this study was to evaluate the efficiency of hemoperfusion (HP) through coated resin adsorbent Synachrom E-5 in animal intoxications with organophosphate inhibitors of cholinesterases type of nerve agents. Five anesthetized dogs were intoxicated with 2 to 6 LD50 of VX substance and another 4 with 2 to 3 LD50 sarine. Both nerve agents were given i.m. after starting 5 h HP. The clinical and laboratory tests were monitored during each HP. HP therapy prevented the development of serious signs of intoxication provided that the administered quantity of both sarine and the VX substance was only 2 doses of LD50. Specific antidote therapy was necessary to prevent cardiorespiratory failure in animals intoxicated with a higher dose of poison. The results obtained show that HP through Synachrom E-5 in intoxication with nerve agents sarine and the VX type is only partially successful.

Bilirubin and bile acids removal by haemoperfusion through synthetic resin "Persorb".

A new type of styrene-divinylbenzene copolymer coated with polyhema was tested for biocompatibility and ability to remove bile acid, bilirubin, phenols and cholesterol in dogs with surgically induced biliary obstruction. After 4-hr hemoperfusion through a polypropylene column containing 325 g of resin, performed 7-10 days after the ligature of the cystic and common bile duct, the serum levels of bile acids, bilirubin, phenols and cholesterol decreased by 60.9 +/- 30.3% (p less than 0.001), 34.8 +/- 12.2% (p less than 0.001), 19.4 +/- 15.6% (p less than 0.001) and 15.3 +/- 4.2% (p less than 0.05), respectively. The procedure was well tolerated, no bleeding or other adverse reactions occurred. The average platelet count decreased by 19.4 +/- 15.6% (p less than 0.05). Hemoperfusion through the Czechoslovak resin coated with polyhema is safe and efficient for removal of bile acids and other protein-bound and lipid-soluble substances which accumulate in cholestatic syndromes and hepatic failure. Thus, it may play an important role in the treatment of such events as a method of artificial liver support.

Diagnostic haemoperfusion.

Haemoperfusion and standard blood culture techniques were compared in the recovery of pathogenic Escherichia coli and Staphylococcus aureus strains circulating in the blood of rabbits with experimental bacteriaemia. On the average, diagnostic haemoperfusion gave positive isolations in 93.3%, blood cultures in 51.7%. This difference in favour of haemoperfusion tended to increase with the decreasing intensity of bacteriaemia. Clinically, haemoperfusion helped to establish correct diagnosis in a 46-year-old female patient with diabetic nephropathy and absceding staphylococcal pyelonephritis, whose blood and urine cultures were repeatedly negative. In this patient the authors succeeded in isolating the cause of septicaemia with the aid of the Czechoslovak haemoperfusion column Hemasorb 400 C. This study implies that diagnostic haemoperfusion used for the isolation of pathogens from blood is more reliable and less time-consuming than routine culture techniques.

Some results of hemosorption columns development and usage in Czechoslovakia.

Hemoperfusion columns packed with active charcoal and a synthetic resin have been manufactured in Czechoslovakia since 1983. In both cases the sorption packings are coated with a layer of poly(2-hydroxyethyl methacrylate). The columns are manufactured in two sizes: for adults (800 ml) and for children (400 ml). The manufacturer is OPS Kolín: the number of columns manufactured so far is 3400.

Resin hemoperfusion in hepatic porphyrias.

In three types of hepatic porphyrias, 32 hemoperfusions over polyhema-coated Amberlite XAD-2 resin were performed. An attack of acute intermittent porphyria subsided after a 6-h hemoperfusion. During the procedure, 13 L of plasma was completely cleared of porphyrins. In a child with variegate porphyria, the laboratory changes were slight and no clinical effect of hemoperfusion was seen. In a patient suffering from porphyria cutanea tarda resistant to standard therapy, 30 hemoperfusions were performed during a period of 10 months. The total plasma porphyrin concentration increased sharply following the start of the treatment, and preceding the fifth procedure it reached a peak of four times the initial value. Since then, the plasma porphyrin level decreased, eventually to one-half the starting value. The mean drop in porphyrin level during each perfusion was 22%. Similar changes were observed in the amount of porphyrins excreted into the urine, which, following an early rise, decreased to 25% of the initial value. However, the patient's skin vulnerability improved only slightly. There were no untoward effects of the treatment.

Long-term support of hepatic excretory function by perfusion of plasma and blood through synthetic resin.

In a patient with advanced primary biliary cirrhosis, 55 resin perfusions were performed which were accompanied by marked improvement in the patient's condition and laboratory findings.

First experience with clinical use of an original hemoperfusion system.

1. The authors present their experience with the use of an original charcoal hemoperfusion system Hemosorb in clinical application, in 9 patients with a heavy metabolic disturbance (failure of the liver and kidney) and after an intoxication with drugs. 2. In two patients the consciousness was remarkably recovered and in one patient it was improved already in the course of the hemoperfusion process, in further two cases the consciousness was recovered in short time after the Hemosorb was used, 7 were completely healed. 3. During the hemoperfusion with Hemosorb there were no symptoms of bad tolerance and no complications except for temporary pyretic reaction in one case. In unique cases manifestations of an enhanced bleeding occurred at the end of the long-term process, which were, however, rather easily corrected. The drop of thrombocytes was essentially reasonable and their restriction after the hemoperfusion was good. 4. Out of metabolic parameters of interest, in the patients with the heavy metabolic failure the drop of total phenol substances, uric acid and creatinine in the blood serum were observed at first stages of the hemoperfusion. The clearance of the total phenol substances and creatinine in the hemoperfusion system was ever rather high. 5. In a patient intoxicated with drugs, there was a remarkable drop of the metaqualone in the blood serum in the course of the hemoperfusion with Hemosorb; the clearance of this compound in the hemoperfusion system was still high after 4 hrs. 6. The first experiences with the clinical application of a new, original hemoperfusion system demonstrated its non-harmful character and biocompatibility as well as clinical, metabolic and toxicologic efficiency.