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Biomedical subjects

W Herrmann

Publications and source records attributed to W Herrmann.

At least 145 records · Page 8Linked to original sources
PubMed1978

Stimulation of precipitation of calcium phosphate by matrix vesicles.

The ability of matrix vesicles isolated from the epiphysial growth plate of 6-week-old chicks to facilitate the precipitation of calcium phosphate was studied in vitro. The vesicles lowered the minimum concentration product [ca2+]X[p1] needed to induce crystal formation, thereby showing the vesicles are nucleators of crystallization. After freezing and thawing the vesicles at pH6.0, part but not all of this ability to nucleate disappeared. Freezing and thawing markedly decreased the Ca and Pi content of the vesicles, suggesting that part of the nucleating activity may have been due to mineral already present. After removal of the mineral the residual nucleating activity could be destroyed by extracting the vesicles with lipid solvents or by treatment with enzymes such as phosphoilipase C, neuraminidase or proteinase. Matrix vesicles obtained from chicks treated with 1-hydroxyethane-1, 1-diphosphonate, a compound that inhibits calcification in vivo, showed impaired nucleating activity, both before and after treatment at pH6.0. The vesicle preparation bound some diphosphonate in vitro, probably to the mineral present in the preparation, since no binding could be detected in vesicles preincubated at pH6.0. No difference was found in the nucleating activity of vesicles isolated from rachitic chicks which had or had not received cholacalciferol 48 h before death. These results suggest that matrix vesicles possess intrinsic nucleating activity that may be important in biological calcification.

Alkaline Phosphatase↗
PubMed1977

[Constellation of lipoproteins in patients with hyperlipoproteinemia and in rabbits fed a cholesterol diet with reference to vascular permeability].

By feeding of rabbits with cholesterol a hyperlipoproteinaemia (HLP) was created and the changes of the cholesterol and triglyceride (TGL) level were compared with the changes of the portions of the pre-beta- and beta-lipoproteins. The electrophoresis with a gel of agar-agarose are more suitable for the densitometric evaluation than electrophoresis with cellulose acetate films. Tests with Evan's blue of the angiopermeability of rabbits feeded with cholesterol showed that the permeability of the cutaneous vessels decreased strikingly during test period, while a change of the permeability of the aorta was not to be proved under the conditions of our tests. HLP patients had been treated with clofibrinic acid, nicotinic acid derivatives and metabolism basic diet for 3 years. The cholesterol and TGL values as well as the pre-beta-/beta-lipoprotein quotients have been determined before and after treatment. The pre-beta-/beta-lipoprotein quotient has proved as suitable complementary parameter for pursuit of the therapeutic result with HLP patients. The changes of the quotients corresponded well with the found changes of the HLP types. The decrease of the TGL content of HLP patients of the type IV or IIb being treated with metabolism basic diet or clofibrinic acid may be estimated (with nearly constant cholesterol level) from the per cent decrease of the pre-beta-/beta-quotient.

Animals↗
PubMed1977

Differential staining of calcified tissues in plastic embedded microtome sections by a modification of Movat's pentachrome stain.

Movat's pentachrome I stain has been adapted and modified as a stain for undecalcified bone sections. After embedding in methyl methacrylate, this procedure yields consistently good results, with an excellent and colorful contrast between mineralized and unmineralized compartments of both cartilage and bone. In addition, osteoblasts, osteoclasts, and other cells and tissue components can easily be differentiated. The staining properties of the lacunar wall surrounding the osteocytes are considered to reflect various states of osteocytic activity. The method is especially useful for the study of bone growth and bone repair, and as a stain for conventional histomorphometry and computer-assisted image analysis in bone biopsies.

Animals↗
PubMed1976

[Primary hyperlipoproteinemia and cardiovascular diseases in relation to age].

The primary hyperlipoproteinaemia is a frequently appearing disease of the second half of life. Out of 188 patients with hyperliporpoteinaemia 19% were at an age of 40-49 years, 33% at an age of 50-59 years and 51% of 60-69 years. The type IV of hyperlipoproteinaemia was the most frequent one (19%), in the second place was type IIa (21%) and in the third place was type IIb (14%). In the 5th decade of life type IV prevailed in males and type IIa in females, in the 6th and 7th decade of life nearly the same percentage for these types was to be found in both sexes. In 60% of the patients with hyperlipoproteinaemia we found a hypertension, in males in 20% coronary insufficiency appeared already in the 4th decade of life, then it rose to 70%, in females these appearances occurred about 10 years later. 9% of the patients fell ill from myocardial infarction. A general arteriosclerosis appeared in 63% of the males and in 89% of the females beginning with the 5th decade of life, then it still increased. Therefore, adequate preventive and curative measures (diet and pharmaca) are necessary in time.

Adult↗
PubMed1976

[Cause and significance of increased endothelial permeability in the development of arteriosclerosis].

The above survey described the physiological and pathological transport of molecules through the arterial endothelium. The barrier function of the endothelium can be interrupted by the humoral substances and such ones be longing to the vascular wall as well as by haemodynamic stress. With the intercellular junctions being opened by destruction or contraction of the endothelium, macromolecular plasma constituents get into the subendothelium where they are retained. By this retentive effect an increased endothelial permeability causes, even with physiological plasma-lipid concentrations, an accumulation of lipoproteins and other large plasma particles in the intima and upper media. The continuous plasma insudation consequently leads to the formation of an intimal regneration tissue, the intimal proliferation. Under the conditions of pathological plasma-lipid concentrations there is to be noticed an acceleration of regeneration processes. Though the new experimental results characterize the endothelial alteration as an initial process, the individual reaction of the vascular wall forms the biochemical and structural correlate of arteriosclerosis. From the results described it can be concluded that the inhibition of permeability disturbances and the involved proliferation processes of the arterial wall as well as the prevention of a hyperlipoproteinaemia are a causative therapeutical basis of prophylaxis and metaphylaxis of arteriosclerosis.

Arteries↗
PubMed1976

Study with a multi-threshold HZE-particle dosimeter using plastic detectors.

During the Apollo 16 and 17 missions two units of the Biostack experiment were exposed to cosmic radiation. In this experiment plastic detector sheets were used for recording and tracing the heavy ions. In some of these sheets the integral energy loss spectrum was measured. The measurements were performed in two different cellulose nitrate materials and in Lexan polycarbonate under 4 g cm-2 and 20 g cm-2 absorber thickness. The individual materials have different energy loss thresholds for the registration of heavy ions. The measured number of particles per cm2 with an restricted energy loss REL greater than REL0, follows a power law a REL(b) with b= -2.18 +/- 0.1 while the value of a depends on the exposure time and the absorber thickness. Calculations show that more than 70% of the fluence in the measured REL region is coming from particles with Z> or =20.

Collodion↗
PubMed1975

[Analytical profile of purified hexetidine (author's transl)].

Physico-chemical, spectroscopic (UV, IR, NMR, mass), chromatographic (GLC, TLC) properties and synthesis of 1,3-bis(2-ethylhexyl)-5-amino-5-methyl-hexahydropyrimidine (hexetidine) are reported and discussed. Moreover, the difference between commercial and purified hexetidine is demonstrated.

Chemical Phenomena↗