Biomedical subjects
H Gans
Publications and source records attributed to H Gans.
Endotoxin inactivation by the humoral components in the tolerant rat serum.
A rapid inactivation of endotoxin has shown to occur following its incubation in serum obtained from endotoxin-tolerant rats with the aid of the limulus amebocyte lysate (LAL) assay. The tolerant rat had large quantities of lipopolysaccharide inhibitor (LPSI) activity, which does not appear to be complement. Heating tolerant rat serum for 60 min at 56 degrees C or the addition of lead acetate to the tolerant serum both resulted in the loss of LPSI activity. This paper focuses on the most unique properties of LPSI, namely it's alteration of activity after heating or the addition of lead acetate, compared with those properties of inhibitors for endotoxin which have been previously demonstrated by a number of investigators.
Enhanced endotoxin clearance in reversed Eck fistula rats during a tolerant stage.
The effects of tolerance to Escherichia coli endotoxin on the clearance activity of the hepatic reticuloendothelial system was examined using the experimental animal model of the reversed Eck fistula (REF). Compared with clearance rate of 51Cr-labeled endotoxin in the normal REF-rat, in the tolerant reversed Eck fistula animals, there was three fold increase in the clearance of endotoxin in the liver. The enhanced endotoxin uptake of the hepatic reticuloendothelial system was observed when the medium containing serum from tolerant animals was infused into the non-tolerant liver with a Harvard pump before the clearance studies, using 51Cr-labeled endotoxin administered via the femoral vein. Heat treatment of tolerant serum at 56 degrees C for 45 min destroyed the enhancing effect. These results suggest that during endotoxin tolerance, humoral factors, particularly complement, play an important role in the uptake of endotoxin from portal vein blood. A direct stimulation of the hepatic reticuloendothelial system may also occur.
Endotoxin inactivating activity of rat serum.
The ability of rat serum to inactivate endotoxin (LPS) was assessed with the aid of the limulus amebocyte lysate assay. Following the addition of various amounts of endotoxin to normal serum the mixture was incubated for 1 hr at 37 degrees C and the residual endotoxin activity determined. One milliliter of rat serum inactivated between 5 and 10 micrograms Escherichia coli LPS per hour. Heating serum for 45 min at 56 degrees C resulted in loss of 80-90% of the LPS inhibitor (LPSI) activity. Serum from cobra venom factor (CVF)-treated rats inactivated between 0.5 and 2.5 micrograms LPS/ml serum. Serum from tolerant rats, even after heating for 45 min at 56 degrees C, inactivates between 10 and 15 micrograms LPS/ml serum/hr; decomplemented tolerant rat serum neutralizes between 5 and 10 micrograms LPS/ml serum/hr. Clearly, the tolerant rat has large quantities of LPSI activity, which does not appear to be complement. The inhibitor found in tolerant rat serum is not species specific since it inactivates Salmonella minnesota and Salmonella typhimurium endotoxins to the same degree and in the same amount as E. coli endotoxin, the agent used to induce tolerance. Both heating serum (56 degrees C) and lead acetate reduce LPSI activity.
External compression with elastic bandages: its effect on the peripheral blood circulation during skin traction.
Experiments were performed in rabbits to evaluate the effects of varying degrees of external pressure on the venous circulation in a limb. For these studies, blood volumes and flow rates were determined on surgically exposed veins using a dropcounter. External compression of 30mmHg caused no impairment of the peripheral circulation. At this pressure, flow rates in the greater saphenous vein and popliteal vein were 74% and 124% of their basal rates, respectively. Venous blood flow was absent at pressures exceeding 70mmHg. In healthy human volunteers, the effects of external application of varying degrees of pressures with an elastic bandage during skin traction on the distal portion of the leg were evaluated by plethysmographic and thermometric techniques. Arterial pulsations obtained by photoelectric plethysmography at external limb pressures of 30mmHg were not significantly different in peak amplitude from those obtained without bandaging. External compression of 70mmHg resulted in a decrease in the basal amplitude at 60 minutes that persisted during the rest of the experiment. At 30mmHg compression, no significant changes of skin temperature were noted in the toe; but, at 70mmHg, the skin temperature dropped to 86% of its basal levels during the first hour followed by a further slow fall. Good immobilization of elastic bandages in skin traction was achieved at 30mmHg pressures. In a comparison of bandage application by skilled and unskilled persons, bandage pressures were much more likely to be optimum when the bandage was applied by the skilled.
Injection corrosion technique.
Explore the source record for details and available documents.
Acute hepatotoxin exposure effects lymphoid and accessory cell types in inbred mice.
The effect of acute hepatotoxin exposure on in vivo and in vitro immune responses were investigated in inbred mice. Splenic anti-SRBC PFC responses were slightly enhanced by carbon tetrachloride or galactosamine administration 5 hr prior to immunization. Whereas splenic anti-SRBC PFC responses were slightly enhanced in euthymic mice exposed to carbon tetrachloride 5 hr prior to immunization, immune responses to the TI antigens, Fl-LPS, Fl-Ficoll, and TNP-LPS, were significantly suppressed. Athymic mice receiving similar hepatotoxin exposure elicited enhanced immune responses to the TI immunogens, thereby suggesting that the activities of B cells and macrophages are enhanced in treated animals and in euthymic mice, T suppressor cells are also activated. By admixture of purified B- and T-cell and macrophage populations from either carbon tetrachloride-treated or control animals, it was demonstrated that hepatotoxin exposure also induces suppressor T cells regulating immune responses to the T-dependent antigen, SRBC, and that macrophages from treated animals are more functional. Further, B-cell responsiveness is enhanced. In addition to these observations, an active factor could be demonstrated in sera from hepatotoxin-treated animals which augments immune responses to SRBC in normal mice and promotes immune responses to this antigen in athymic mice. These findings indicate that the effects of acute hepatotoxin exposure are multifocal, influencing the activity of lymphoid and accessory cells.
Endotoxins and hepatorenal syndrome.
Explore the source record for details and available documents.
A rat model for study of bilirubin conjugation by a cultured cell/ artificial capillary liver assist device.
The Gunn rat, congenitally lacking the conjugating enzyme glucuronyl transferase, provides an animal model for the study of bilirubin conjugation by an extracorporeal liver assist device (LAD) composed of cultured cells and artificial capillaries. Rat hepatoma cells of the H4-II-E cell line able to form conjugated bilirubin glucuronide from bilirubin were grown to tissue density by circumfusion culture of the LAD before symbiotic hemoperfusion experiments lasting up to 24 hours. Rat bile was analyzed by thin layer chromatography for bilirubin glucuronide which was formed by the device and then excreted by the rat.
Xenografted transplanted cells.
Explore the source record for details and available documents.
Evaluation of the possible role of serum factors in the clearance of endotoxin from blood.
Explore the source record for details and available documents.
Personal experience with tympanoplasty in children.
An analysis is presented of a series of 434 operations in chronic otitis media in children taking into account the extent of the lesion, the type of operation, the early and late functional and morphological results. In 18% of cases a radical operation was performed, in 21% atticotomy or other conservative operations, and in 61% open or closed tympanoplasty. Because of dynamic character of the cholesteatomatous process in childhood, the creation of a "safe ear", i.e. free of recurrences of cholesteatoma, is difficult by means of closed tympanoplasty operations.
Tradition and innovation: reflections on selected historical highlights in the field of hepatic surgery.
Explore the source record for details and available documents.
Mechanism of heparin protection in endotoxin shock.
Blood clearance by phagocytosis, predominantly by the liver, presents an important mechanism for the elimination and detoxification of endotoxin. However, its effectiveness alone does not determine the outcome of an experimentally induced standardized endotoxin shock. Consequently other effects elicited by endotoxin--for instance, those on the coagulation mechanism or on an endotoxin-detoxifying enzyme system in plasma--must also play an important role in determining the ultimate fate of this condition, for it is now abundantly clear that interrupting such effects with heparin provides considerable protection.
Treatment of acute orbital complications.
Explore the source record for details and available documents.
Are enteric endotoxins able to escape from the intestine?
Explore the source record for details and available documents.
Evaluation of the effects of the finger fracture technique used in hepatic resection.
Explore the source record for details and available documents.
Effect of ligation of the hepatic artery or occlusion of the portal vein on the development of endotoxema.
Explore the source record for details and available documents.