Biomedical subjects
Publications and source records attributed to D Falkenhagen.
Due to their partial permeability and their good mechanical properties, the symplex capsules are technically suited for an application in extracorporal detoxification. By this newly developed procedure the activity of encapsulated enzymes is considerably increased; thus, application for extracorporal detoxification seems to be advisable.
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Rat liver microsomes were microencapsulated in a pure aqueous medium by means of a new technique. The wall of the microcapsules consists of a semipermeable simplex membrane which is stabilized mainly by electrostatic interactions between a polymeric polyanion (sodium cellulose sulphate) and a polymeric polycation (polydimethyldiallylammonium chloride). The metabolic as well as the mechanic parameters of the microcapsules could be markedly improved by separating the metabolic (liver microsomes) from the membrane component (sodium cellulose sulphate) in such a way that two distinct compartments are formed during the preparation of the microcapsules.
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Normal leukocyte functional capacity was investigated by evaluation of phagocytosis of opsonised yeast cells in a radiometric test system. After incubation with dialysis membranes (different cellulosic membranes, polysulfon membrane (PS), polymethylmetacrylate membrane (PMMN), the phagocytosis index, expressed as percent decrease with respect to initial values without membrane, decreased by 10%-25%. The most pronounced effect was observed with PS, cuprophane, modified cellulose and PMMA. The results are not related to differences in the viability of PMN during the test procedure; dead PMN amounted to about 4-6.5%. A significant increase in beta-NAG and beta-Gluc activities was released in the supernatants of the phagocytosis suspensions. This increase activity can be explained by the phagocytosis of PMN but it was not influenced by membrane contact. There was no influence of membrane contact or phagocytosis activity of PMN on the beta 2 M concentration in the supernatant demonstrating that no in vitro generation during incubation with either membrane exists.
The 1-pool-model of sodium kinetics during hemodialysis is based upon the assumption of an immediate compensation of osmotic shifts. This assumption is not supported by measurements of plasma sodium, total protein concentration and colloid osmotic pressure kinetics. When a high dialysate sodium concentration is applied, an inflow of sodium into the plasma space occurs, which results in an osmotic suction and thus a plasma dilution. These conditions can be represented by a 2-pool-model taking into consideration capillary filtration. The results indicate that following the first treatment period the sodium kinetics are sufficiently explained by a 1-pool-model with the total body water as distribution volume. Both the plasma sodium concentration and the eliminated sodium at the end of a hemodialysis treatment can be described to an acceptable level by the 1-pool-model. The input of the measured in-vivo sodium dialysance value (or alternatively the urea clearance) is necessary.
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The release of biological active factors from blood cells, e.g. interleukin 1, is of importance with regard to the bioavailability testing of membranes for extracorporeal blood purification. The data from an in vitro system of cytokine release may show a connection between complement activation and cytokine (interleukin) release of membranes. In contrast the results of the generation rate of beta 2-microglobulin did show no definite reference to complement activation or cytokine release. Further time-dependent investigations of the generation rate beta 2-microglobulin are necessary.
On the view of 1989 older and modern developments to a bioartificial implantable hybrid kidney are presented. To the realization proof of the implantable hemofilter-intestine-hybrid kidney the routes were described in an experimental rat model to the plasmakinetic simulation of the urea and sodium level as a marker of the hybrid kidney functions. The results of the bioartificial hemofilter-intestine-hybrid kidney development are presented, but significant detail problems must be solved, especially the hemofilter biocompatibility problem.
In 11 female patients with chronic uraemia at the age of 20 to 47 years (average age 33.1 years) the basal and the thyrotropin releasing hormone-(TRH-) stimulated thyroid gland stimulating hormone-(SH-) secretion were investigated, in addition to this the parameters of the thyroid gland total thyroxin (T4), thyroxin binding capacity (TBC) as well as the free thyroxin-index (FT4-I). In 2 women the investigations were repeated after kidney transplantation. The determination of TSH and T4 was carried out radioimmunologically, TBC was determined according to the principle of the test tube analysis, whereas FT4-I was established by computation. In 9 of the 11 female patients with chronic uraemia a physiological TSH-response behaviour is existing, whereas for T4 deviations from the reference area are to be stated in 7 female patients and for FT4-I in 6 female patients.
In 11 female patients with chronic uraemia at the age of 20 to 47 years (average age: 33.1 years) the behaviour of basal and stimulated serum levels of prolactin (PRL), growth hormone (HGH) and gonadotropins (LH, FSH) was investigated. For stimulation of the hormone secretion a sequential test with arginine hydrochloride, gonadotropin releasing hormone (GnRH) and thyrotropin releasing hormone (TRH) was used. In 2 women the investigations were repeated after kidney transplantation. The determination of LH, FSH, PRL and HGH was performed radioimmunologically. The investigations show that in women with chronic uraemia the basal LH-levels in general lie clearly above of those ones of women with biphasic cycles, whereas the FSH-levels are not increased. The LH-response after administration of 25 micrograms GnRH is adequate in 6 women and is absent in 5 women. After kidney transplantation a clear reduction of the basal LH-levels in comparison to the preliminary values is to be established. The increased basal LH-levels are causally made responsible for the disturbances of the menstrual cycle in women with chronic uraemia. For PRL hyper- and normoprolactinaemic as well as hypoprolactinaemic basal levels are found. A connection between the height of the PRL and creatinine levels cannot be proved. Apart from a adequate PRL response to the stimulation with TRH in the individual case this response is inadequate or is absent. The basal HGH-levels are in the area of reference. In all women HGH can adequately be stimulated, whereby the case in question is presumably a so-called paradoxical TRH-effect.
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In 11 patients with chronic uremia both the basal and stimulated levels of LH and FSH in serum were determined by RIA. After renal transplantation the investigations were repeated in 2 cases. The basal levels of LH were unphysiologically increased whereas FSH was found in the normal range. The stimulation of LH by GnRH was adequate in 6 patients and in 5 there was no response. As a result of renal transplantation there was a drop of LH in serum. It is supposed that the unphysiological increase of LH in patients with chronic uremia is the cause for the disturbances of the menstrual cycle.
In 11 patients with chronic uremia both the basal and TRH stimulated TSH levels and T4, TBC and FT4-I were determined. The investigations were repeated in 2 cases after renal transplantation. TSH and T4 in serum were determined by RIA, TBC by radio reagent assay. FT4-I was calculated. In 8 patients the basal TSH levels were in the normo- and in 3 in the hypothyreotropic range. In 9 patients the response to TRH was adequate. There were deviations from the physiological range in 7 patients for T4 and in 6 for FT4-I.
In 11 patients with chronic uremia both the basal and the stimulated levels of PRL and HGH were determined by RIA. The investigations were repeated in 2 patients after renal transplantation. The basal PRL levels were as well hyper- and normoprolactinemic as hypoprolactinemic. Also the PRL response did not show any uniform tendency to the TRH stimulation. After renal transplantation in 1 patient there was a decrease of the hyperprolactinemic serum levels into the normoprolactinemic range whereas the response was not influenced to TRH. Both the basal and the stimulated levels of HGH were in the physiological range. The response of HGH to the stimulation is explained as the so-called paradox TRH effect underlined by missing of the stimulation after renal transplantation.
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