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Biomedical subjects

M Böttcher

Publications and source records attributed to M Böttcher.

At least 55 records · Page 3Linked to original sources
PubMed1986

Preclinical evaluation of haemosorbents.

The selection of assessment procedures for the preclinical evaluation of haemosorbents and the relationship between such procedures and the intended application are exemplified by examination of the design and utilization of procedures based on the rat. Procedures are described for haemoperfusion and for membrane plasma separation followed by on-line sorbent treatment of plasma (plasma perfusion). These procedures are suitable for single or repeated use, with the animal in an unrestrained and conscious state. The relevance to the intended application is demonstrated with respect to artificial liver support by the ability of rat extracorporeal circuits to provide information on the relationship between sorbent properties and liver regeneration as determined by the proliferative response following partial hepatectomy.

Adsorption↗
PubMed1986

Experiments with continuous hemofiltration and hemofiltrate regeneration in the rat.

Experimental studies were made with continuous hemofiltration treatment for bilaterally nephrectomized rats and initial observations regarding the effects of such treatment on leukocyte and thrombocyte counts are reported. Hemofiltration of unanesthetized rats able to move freely within their cage could be continued for up to 30 h using a pump-driven ECC system. Blood parameters recorded during this treatment indicate that the detoxification was effective. In another series of experiments the water and electrolyte reabsorption capacity of the colon ascendens of healthy rats was tested by continuously supplying NaCl solution into the colon via a fistula. A large proportion, if not all, of the hemofiltrate can be discharged into the colon without diarrhoea. A final series of experiments showed that the three-stage operation (implantation of permanent catheters, connection of a permanent intestinal fistula and bilateral nephrectomy) is possible with the rat.

Animals↗
PubMed1984

[Animal experiments using the left-ventricular-assist system].

The left ventricular assist device (LVAD) was tested in 27 sternotomied dogs using hemodynamic parameters. The left ventricular failure was attained by the starvation of the coronary vessels. The use of cannulae and ventriculi fitting for the size of the animals, and a diastolic vacuum were an essential premise for an effective support of the left heart. By variation of the latent period, the systole duration, and the operating pressures were selected for optimal pumping conditions. The effectiveness of the LVAD was shown by the detected pressure and flow parameters.

Animals↗
PubMed1983

[Comparative estimation of monocompartmental methods of analyzing 99m-Tc-diethylenetriamine pentaacetic acid clearance by declining plasma levels with special reference to long term studies].

Plasma slope clearance estimation with 99m-Tc-DTPA corresponds to total clearance determination. When activity is measured directly in cumulative serum samples, determination of the plasma slope clearance is suitable for practical applications only if simplified analytic procedures are used. Monocompartmental analytic procedure that take the late slope of the disappearance curve into account are particularly useful for GFR estimation. The A3k3-slope-clearance analysis method is a monocompartmental procedure for determining slope clearance that is based on activity measurements between the 100th (120th) and 240th minute after injection. Compared with other monocompartmental procedures, the A3k3-clearance method shows a highly significant hyperbolic correlation with serum creatinine, a highly significant linear correlation with inulin total clearance, is age dependent and yields reproducible results. The sensitivity (frequency of correct function results in the case of disturbed glomerular function) of the A3k3-slope-clearance method with 99m-Tc-DTPA is particularly good. The practically important predictability of pathological A3k3-clearance results (frequency of correct results when the kidney function is truly reduced) is on the average 85%. The mean efficiency of the method is 88% (65-97% at the 95% confidence-level).

Animals↗
PubMed1983

[Possibilities for using extracorporeal circulation in the rat].

An extracorporal system of freely mobile, unanaesthetized rats is presented. This model was used in experiments on the biocompatibility of silicone rubber and new types of hollow membranes. The results confirm a sensitive reaction of haematological parameters to various test substances, thus indicating that the model is very suitable. Carrying out a membrane plasma separation in rats makes it possible also to use rats for studies on detoxification and thus to use the advantages offered by this experimental animal to the full.

Animals↗
PubMed1983

[What is the current outlook for an implantable artificial kidney?].

Considering the homeostatic demands made by the organism on an artificial eliminating substitute kidney system, it seems that the haemofiltrative principle for transporting matter is the most suitable for simulating the natural glomerular kidney function in an implantable artificial kidney. Biophysical laws can be used to influence long-term filtrative efficiency and the blood-flow in the haemofilter system can be controlled by technical feedback regulation. Endogenically, the filtration process is, in terms of energy, driven by the aterial blood pressure (specifically, by the trans-membrane pressure thus generated). The definitive ultrafiltrate treatment takes place by intestinal reabsorption and elimination of the end products, whereby these functions may be assisted by the use of sorbents etc. or an adequate substitution therapy if reabsorption is insufficient. These processes can reasonably be triggered by neurohormonal feedback regulation if the homeostasis situation is greatly disturbed by the haemofiltration process. The implantable artificial kidney is thus a biochemical hybrid kidney.

Animals↗
PubMed1982

The antenatal use of ambroxol (bromhexine metabolite VIII) to prevent hyaline membrane disease: a controlled double-blind study.

A prospective double-blind clinical trial was carried out to determine whether ambroxol (bromhexine metabolite VIII) treatment (1000 mg/day for a period of 5 days) reduces the risk of hyaline membrane disease (HMD) in potentially premature infants. Amniocentesis was performed before the first and 24 h after the last application of ambroxol or placebo to assess the development of the total phospholipid phosphorus content, the L/S ratio, the P/S ratio, and the properties of the surface tension of the amniotic fluid after ambroxol or placebo. There were 246 infants born to 224 mothers. Of the 116 infants with less than or equal to 36 completed weeks' gestation, 56 were in the ambroxol and 60 in the placebo group. No differences between groups occurred in risk factors for HMD (diabetes, asphyxia, male sex, cesarean section). Statistically significant differences in favor of the infants in the ambroxol group were found in the HMD incidence: 23.2% in the ambroxol group compared with 41.7% in the placebo group (p less than 0.05). There was no reduction of the HMD incidence in the less than or equal to 32-week gestational age category in the ambroxol group compared with the placebo group inspite of the fact that all the examined parameters for determining lung maturity reflected a stimulatory effect of ambroxol compared with the results of the placebo group, particularly before the 33rd week of gestation. Prolonged rupture of the membranes played no protective role against HMD.

Ambroxol↗
PubMed1980

[Is the inulin (and PAH) clearance test obsolete in renal functional diagnosis?].

1. It could be confirmed that the endogenic creatinine clearance overestimates the GFR. This overestimation increases with the restriction of the glomerular filtration. 2. By the biphasic pump-regulated permanent infusion of inulin and PAH a constant equilibrium was reached and the clearance was calculated according to the classical formula (output method) as well as from the addition of the test substance (input method) and compared. 3. The comparison of the two clearance techniques results in significantly higher value for inulin as well as for PAH in the input technique. 4. By clearance equations the relation of input and output clearance can be made. The correlation coefficient for the different investigation techniques for the estimation of the inulin clearance was 0.83, for the PAH-clearance 0.88.

Aminohippuric Acids↗