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Biomedical subjects

K Oette

Publications and source records attributed to K Oette.

At least 55 records · Page 3Linked to original sources

Prevention of experimental liver metastases by D-galactose.

The metastasis of malignant tumors from a primary site to near and distant secondary sites is probably the most important event in the pathogenesis of cancer and it accounts for most cancer deaths. Whereas advances in the treatment of primary cancer have led to increased patient survival, metastatic cancers are still the most difficult group of diseases to treat successfully. As organ-characteristic lectins play an important role in the organ manifestation of metastatic islets, it might be possible (e.g. during surgical operations on malignant tumors) to block those organ-characteristic lectins with the appropriate receptor-bearing glycoconjugates in order to inhibit the metastatic spread. Recent experiments have demonstrated that neuraminidase treatment of tumor cells (mouse sarcoma-1) alters in vivo (Balb/c-mice) the organotropic distribution of metastases; instead of being found exclusively in the lung, they are found both in lung and liver. However, pre-injection and regular application of D-galactose--the same holds for arabinogalactan--prevents the setting of metastases in the liver but does not influence the metastatic process to the lung, whereas mannan--as a galactose-free control substance--does not alter the initial pattern of metastasis to lung and liver.

Animals↗

Inhibition of liver metastasis in mice by blocking hepatocyte lectins with arabinogalactan infusions and D-galactose.

According to our hypothesis, organ-specific lectins (e.g., the D-galactose-specific hepatic binding protein) play an important role in the organ location of metastatic malignant cells. The rapid clearance and uptake by the liver of tritiated alpha 1-acid-(asialo)glycoprotein from the circulation of Balb/c mice was markedly delayed after preinjection of D-galactose or arabinogalactan. The preinjection (1 h) and regular application (for 3 days after tumor cell inoculation in Balb/c mice) of the receptor blocking agents D-galactose and arabinogalactan prevented the settling of sarcoma L-1 tumor in the liver completely, but did not influence the settling in the lung. Other galactans, dextrans, and phosphate-buffered saline showed no effect. Therefore, when lectins were blocked with competitive-specific glycoconjugates, colonization was prevented.

Animals↗

Increased prevalence of apolipoprotein E2 in patients with retinitis pigmentosa.

Apolipoprotein E isoforms were determined in 139 unrelated patients with retinitis pigmentosa (RP). When compared to prevalence rates for the general population in Germany, an increased prevalence was observed for phenotypes E2/E2: 10.1 vs. 1.0% (p less than 0.001), E2/E3: 19.4 vs. 12.0% (p less than 0.05), and E2/E4: 5.8 vs. 1.5% (n.s.), while the prevalence appeared to be reduced for phenotypes E3/E3: 48.9 vs. 59.8% (n.s.) E3/E4: 13.7 vs. 22.9% (p less than 0.05), and E4/E4: 2.2 vs. 2.8% (n.s.). These findings suggest that genetically determined abnormalities of plasma lipoprotein metabolism may be associated with some forms of RP.

Apolipoprotein E2↗

[Regression of coronary sclerosis in familial hypercholesterolemia IIa by specific LDL apheresis].

The long-term effect of specific LDL plasma immunabsorption on the course of coronary arteriosclerosis was tested in ten patients with familial hypercholesteremia type IIa (seven females, three males; age range 15-57 years). Available were ECG, bicycle ergometry, hemodynamic and angiographic data. These tests were repeated seriatim in the course of the LDL immunabsorption. It was found that exercise tolerance markedly increased, ischemic ST-changes became less marked and the initial hemodynamic parameters remained unchanged. The morphology of the coronary arteries was influenced lastingly: among 22 stenoses only one progressed, there was no further progression in 11 stenoses and regression in ten. When there was generalized arteriosclerosis, progression occurred in two of 79 coronary artery segments, progression was arrested in 56 and regression was noted in 21 of 79 segments. These results demonstrate that specific LDL plasma immunabsorption for the elimination of LDL cholesterol favorably influences the course of coronary arteriosclerosis in patients with familial hypercholeremia type IIa. The findings support the lipid theory of atherosclerosis and coronary arteriosclerosis, at least in this special group of patients.

Adolescent↗

[Effect of postoperative human albumin therapy on serum protein fraction of septic and aseptic patients].

The effects of 20 and 40 g postoperative intravenous human albumin (HA) infusion on the serum protein fractions and on the colloid osmotic pressure (COP) were analyzed in 72 septic and aseptic patients. Only aseptic patients showed an increase in the COP as well as the serum albumin concentration during at least a 24-h-period. In septic patients, however, the increased serum albumin concentration dropped rapidly to the initial values. This can be only explained by a disturbance of the membrane permeability. In contrast, the behavior of the serum globulin concentration was not essentially influenced by septic or non septic conditions.

Adult↗

Analysis of cardiovascular risk factors in chronic hemodialysis patients with special attention to the hyperlipoproteinemias.

A group of 252 chronic hemodialysis patients was examined for various risk factors. Special emphasis was placed upon the comparison of patients who had marked cardiovascular alterations with the remainder of the group. The seriousness of the risk factors was determine by hypertension and hyperlipoproteinemia, 78% of the patients received antihypertensive medication or had changes in the fundus of the eye or both. In 74% of the patients there were pathological changes in the plasma lipids or lipoproteins or both. Hypertriglyceridemia (49%) and a HDL cholesterol decrease (61%) were the most striking findings. The average VLDL cholesterol value was significantly higher and the HDL cholesterol significantly lower in the coronary heart disease group than in the remaining group. These results show that hyperlipoproteinemia and a decrease in HDL, together with other risk factors such as hypertension and anemia, play an important role in the accelerated development of atherosclerosis in a hemodialysis group.

Age Factors↗

[Polarimetric determination of alpha-amylase activity (author's transl)].

In the study of the relatively slow amylase-catalysed hydrolysis of oligosaccharides, it is assumed that the subsequent mutarotation has essentially no effect on the kinetics of the total reaction. Relatively large sampled and long measurement times (slow rate of change in angle of rotation) are necessary for the polarimetric determination of alpha-amylase activity. For these reasons, only urine and duodenal juice are suitable as sample sources. Owing to the absence of coupled reactions and auxilliary enzymes, the polarimetrically determined kinetics are generally more representative of the true kinetics of the amylase reaction, than those obtained with fully enzymic methods; in addition, single determinations by the polarimetric method are less subject to interference by sample components. With measurement times in the order of minutes, the polarimetric method shows excellent linearity, very good proportionality between analytical response and quantity of enzyme, and good precision in series (CV = 1.3%). Comparison of the polarimetric with a chromogenic and a fully enzymic method showed an acceptable correlation (r for each method was about 0.98). T, the polarimetric method shows excellent linearity, very good proportionality between analytical response and quantity of enzyme, and good precision in series (CV = 1.3%). Comparison of the polarimetric with a chromogenic and a fully enzymic method showed an acceptable correlation (r for each method was about 0.98). T, the polarimetric method shows excellent linearity, very good proportionality between analytical response and quantity of enzyme, and good precision in series (CV = 1.3%). Comparison of the polarimetric with a chromogenic and a fully enzymic method showed an acceptable correlation (r for each method was about 0.98). The advantages and disadvantages of the polarimeatric method, with consideration of possible interfering factors, are discussed.

Amylases↗

[On the biosynthesis of glyceride- and phosphoglyceride analogues from monoglyceride analogue 2-(linoleoylamino)-1,3-propanediol in rats (author's transl)].

From L-serine 2-(linoleoylamino)-1,3-propanediol, a monoglyceride analogue, was synthesized and characterized by thin-layer and gas chromatography, infra red spectroscopy and mass spectrometry. After oral application to rats there was an accumulation, almost exclusively in the liver, of triglyceride, diglyceride, phosphatidylcholine and phosphatidylethanolamine analogues with amide-bound linoleic acid. Small amounts of triglyceride analogues could also be detected in the adipose tissue. The analogues were chromatographically isolated using in addition enzymatic and non-enzymatic hydrolysis procedures. Results disclosed that the amide-bound fatty acid of 2-(linoleoylamino)-1,3-propanediol can be absorbed and metabolized intact. Phosphoglyceride analogues are probably formed by the CDP-choline and CDP-ethanolamine pathway fromdiglyceride analogues. Phosphatidylcholine and its analogues disclosed a similar composition of the 1-O-acyl fatty acids. Apparently analogues have in vivo similar substrate properties to hydrolases and acyltransferases as their natural counterparts.

Animals↗

The lipoprotein abnormality in Tangier disease: quantitation of A apoproteins.

In this study we have determined by radioimmunoassay and double immunoelectrophoresis the total quantities and distributions of A apoproteins in three adult patients affected with Tangier disease (hereditary alpha-lipoprotein deficiency). Compared with normal plasma, the total quantities of apoproteins A-I and A-II in Tangier plasma were determined to be less than 1% and 5-7%, respectively. In Tangier patients, approximately 90% of the apoprotein A-I sedimented when ultracentrifugations of plasma were carried out at density 1.21 g/ml KBr. By contrast, more than 95% of the apoprotein A-II floated under those conditions. In normal plasma, approximately 90% of both apoproteins A-I and A-II is found in the 1.063-1.21-g/ml KBr density fraction. These findings suggest that complete dissociation of A apoproteins occurs in Tangier plasma. This dissociation of apoproteins was confirmed by double immunoelectrophoresis with monospecific antisera. Immunochemical and electrophoretic experiments did not provide evidence for a structural abnormality of apoprotein A-I in these patients, The results taken together strongly suggest that normal high-density lipoproteins are absent from Tangier plasma.

Adult↗