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Biomedical subjects

A L Boks

Publications and source records attributed to A L Boks.

15 recordsLinked to original sources
PubMed1991

Disinfection of fiberscopes by thermochemical disinfection.

A new fully automated washing and disinfection machine for fiberscopes was evaluated. This apparatus, the Endoscopic Thermo Disinfector (ETD) uses a combination of heat and a brand name disinfectant containing glutaraldehyde to fulfill its purposes. The disinfectant showed effective antibacterial activity at the concentrations used in the ETD. After artificial contamination of fiberscopes with high concentrations of various bacteria the washing and disinfection process was completely effective. Contaminated debris was also effectively removed from fiberscopes and from the inside of the washing machine during this process. A number of improvements in the design of the washing machine were implemented during the test period and suggestions for further improvements will be considered. Taking into consideration the reported effects of the disinfectant used against viral pathogens, the ETD washing machine effectively cleans and disinfects flexible watertight endoscopes.

Disinfection↗
PubMed1989

Quantitation of plasma levels of tetranectin--effects of oral contraceptives, pregnancy, treatment with L-asparaginase and liver cirrhosis.

Tetranectin is a tetrameric protein that binds to kringle 4 of plasminogen. Increase of electrophoretic mobility of the otherwise slowly migrating tetranectin in the presence of ethylenediaminetetraacetate was used to develop a reproducible electroimmunoassay to quantify plasma levels. Plasma levels in normals were found within narrow limits of 100 +/- 16 (SD)%, (100% = 0.15 mumol/l). There was no difference between males and females, smokers and non-smokers, and there were no significant changes with age from 20 to 49 years. Patients with severe liver cirrhosis showed a large variation in plasma tetranectin levels but no systematic or average reduction, in contrast to strong reductions in plasma levels of other proteins. Patients treated with L-asparaginase showed a gradual reduction in time in plasma levels of various proteins, though tetranectin showed no significant reduction. It is concluded that tetranectin can be assayed reproducibly in plasma and has a well regulated plasma level. This level is not sensitive to conditions with reductions in synthesis of many proteins, such as during cirrhosis of the liver and during L-asparaginase therapy. The reductions in plasma levels during the use of oral contraceptives and pregnancy indicate involvement of sex steroids in the metabolism of tetranectin.

Adolescent↗
PubMed1989

Use of protein profiles to identify Acinetobacter calcoaceticus in a respiratory care unit.

The presence of acinetobacters in a respiratory care unit was prospectively studied because of an increase in the number of isolations of Acinetobacter calcoaceticus. Cell envelope protein electrophoresis was used to distinguish strains. Eleven protein patterns were observed in isolates from patients and their environment. One pattern (pattern 1) was seen in several patients and environmental samples. Another pattern (pattern 2) was identified repeatedly in samples from skin and mucous membranes of patients in the same ward. After thorough cleaning was undertaken throughout the unit, the pattern 1 strain was no longer cultivated from clinical samples. It is concluded that cell envelope protein electrophoresis is a useful method for tracing epidemic strains of A calcoaceticus.

Acinetobacter↗
PubMed1987

A reproducible model of acute hepatic failure by transient ischemia in the pig.

A model of transient acute hepatic failure has been developed in the pig. Three days after a functional end-to-side portacaval shunt was introduced, 15 ambulant animals underwent total liver ischemia for 4 to 6 h by the closure of a mechanical clamp surrounding the hepatic artery. Four of the eight animals subjected to 4 hr of ischemia survived. All but one of the animals undergoing 6 hr of hepatic ischemia developed grade 4 encephalopathy after 24 to 30 hr and died within 50 hr. Quantitative estimation of liver cell necrosis revealed less than 40% necrosis in the survivors, and approximately 62% (range 49-75%) in animals who died of hepatic coma. As far as the putative toxins are concerned, significant differences were found between animals undergoing 4 and those undergoing 6 hr of ischemia, especially in the plasma ammonia levels and the plasma ratios for tyrosine and phenylalanine. Plasma arginine levels had fallen to zero in both groups at 24 hr and only rose to preischemic values in animals who survived. This large animal model fulfills the accepted criteria of potential reversibility, reproducibility, and death due to hepatic failure.

Amino Acids↗
PubMed1986

A simple device for disinfecting endoscopes.

A method for disinfecting fibreoptic endoscopes with povidone-iodine and a simple cleaning device, consisting of a curved glass pipe and a peristaltic pump is described. If properly employed the system produces satisfactory results.

Disinfectants↗
PubMed1986

Hemodynamics and coagulation in experimental auxiliary liver transplantation during fulminant hepatic failure.

In pigs, ischemic liver cell necrosis was induced by 6 hours' occlusion of the hepatic artery and the portal vein 3 days after construction of a side-to-side portacaval shunt and division of the hepatic ligaments. Two thirds of the liver of an MLC-compatible donor was heterotopically transplanted 13 hours (group I), and 3 hours (group II) after induction of liver failure. In group I (N = 11), three animals died of liver failure before or shortly after induction of anesthesia. Of the remaining pigs, two animals survived more than 2 weeks. In group II (N = 10), intraoperative hypotension was prevented by reduction of the interval between liver failure and transplantation and by thermodilution catheter monitored fluid replacement. A significant decrease in cardiac output and an increase of pulmonary and systemic vascular resistance were observed during auxiliary partial liver transplantation (APLT). In the immediate postoperative period, six pigs died of deficiencies in hemostasis that were caused by consumptive coagulopathy related to severe host liver damage rather than fibrinolysis. Two pigs in group II survived in good condition 12 and 42 days after APLT. In the longer surviving pigs of both groups, either the graft or the host liver recovered. Processes that might be responsible for the observed hemodynamic changes and coagulation disorders are discussed. These results indicate that APLT is technically feasible in severely ill pigs with acute hepatic failure.

Anesthesia, General↗
PubMed1985

Protraction of whole blood and plasma clot lysis in patients with high levels of an inhibitor of tissue-type plasminogen activator.

The influence of the newly discovered, fast-acting inhibitor of tissue-type plasminogen activator (t-PA) on the lysis time of plasma clots was studied by visual observation of lysis of clotted citrated plasma after addition of purified t-PA. To a series of plasma samples with various concentrations of naturally occurring PA-inhibitor purified t-PA was added to a final concentration, which in pooled normal plasma is sufficient to induce clot lysis within a few hours. In those plasma samples with a high free inhibitor level, determined by measuring the recovery of the activity of added purified t-PA, clot lysis was retarded. Whole blood clots were made by clotting freshly collected non-anticoagulated blood with thrombin after admixture of a trace amount of radiolabeled fibrinogen and a fixed amount of t-PA. Lysis rate, read from the appearance of radioactivity in the serum after centrifugation, was significantly lower in clots obtained from subjects with a high free inhibitor level than in those with a low inhibitor level. It is concluded that the PA-inhibitor protracts clot lysis and may be relevant for physiological fibrinolysis.

Blood Coagulation↗
PubMed1985

Auxiliary transplantation of part of the liver improves survival and provides metabolic support in pigs with acute liver failure.

In pigs subtotal ischemic liver cell necrosis was induced 4 days after auxiliary transplantation of 60% of the liver of an MLC-compatible donor (ATPL group, n = 13). In control animals (n = 14) temporary liver ischemia was preceded by division of the hepatic ligaments and creation of an end-to-side portacaval shunt. In the ATPL group six animals died of gastric hemorrhage, intestinal strangulation, or sepsis. The remaining seven animals survived in excellent condition until sacrifice 26 days after the induction of liver ischemia. Excellent graft function was demonstrated by uptake and excretion of 99mTc-HIDA at cholescintigraphy, ammonia detoxification, synthesis of clotting factors and glucohomeostasis. EEG recordings in the animals that underwent transplantation did not change from preischemic levels. Evidence of hepatic regeneration was found in the transplanted livers but could not be demonstrated in the damaged host livers. The control animals died in coma within 72 hours. These results indicate that auxiliary transplantation of a partial liver provides metabolic support and improves survival in animals with induced acute liver failure.

Acute Disease↗
PubMed1985

In vivo experiments with powder charcoal haemoperfusion (filmadsorber) in a pig model of hepatic failure.

The filmadsorber, an experimental haemoperfusion column containing activated powder charcoal embedded in a colloidal film, has been tested in pigs with ischaemicnecrosis of the liver. Haemoperfusion with a flow of 200 ml/min was performed for a duration of 4 to 6 hours. Bile acid clearances varied between +/- 52 ml/min (1st hour) and +/- 23 ml/min (6th hour). Clearances for aromatic amino acids were initially even higher (phenylalanine 115, tyrosine 112 and methionine 46 ml/min). No ammonia was removed. Side-effects were minimal, although platelets fell 24 +/- 15%. We conclude that haemoperfusion with the filmadsorber is well tolerated and associated with high clearances for bile acids and some amino acids, particularly in the first hours of treatment.

Acute Disease↗
PubMedDate not supplied

Hemostasis and fibrinolysis in severe liver failure and their relation to hemorrhage.

In a study of severe, decompensated liver failure, we tried to find a correlation between hemorrhage and parameters of hemostasis and fibrinolysis. Three groups of patients were studied: alcoholic cirrhosis; nonalcoholic cirrhosis, and acute liver failure without known prior liver disease. The two cirrhotic groups did not differ significantly from each other in coagulation or in fibrinolytic parameters, although liver function was more impaired in nonalcoholic cirrhosis. The levels of clotting factors, antithrombin III, prekallikrein, plasminogen and alpha 2-antiplasmin were significantly lower in the third group. Mean values of fibrinolytic activity (fibrin plate method) were slightly reduced as compared to normal in all three groups. Tissue plasminogen activator-related antigen tended to be elevated especially in alcoholic cirrhosis. The free fast-acting plasminogen activator inhibitor showed extremely high and extremely low levels in some patients among all three groups. Nonvariceal, capillary-type bleeding, including mucosal bleeding, hematomas and bleeding from puncture sites correlated with low thrombotest and normotest levels (p less than 0.01), low fibrinogen concentration (p less than 0.05) and with a high quotient of fibrinolytic activity (square root of lysis area) and normotest (p less than 0.001). The ratio between fibrin formation and dissolution appears to be an important parameter of hemorrhagic tendency in liver disease. Variceal bleeding appeared not to be related to impairment of hemostasis or fibrinolysis.

Acute Disease↗