The aim of this study was to investigate the extent of lysyl and prolyl hydroxylation of collagen I in osteoporosis and compare it with collagen I from "bone healthy" individuals. Collagen I was isolated from femoral heads of osteoporotic women, from women suffering from osteoarthrosis of the hip, and from healthy women 60-85 years of age. The femoral heads were dissected into compact and trabecular bone of the neck region and from trabecular bone of the head region, and collagen I was extracted by limited pepsin digestion. The amino acid analysis of individual alpha-chains showed a remarkably higher degree of hydroxylation of lysine residues both in the alpha1(I)- and in the alpha2(I)-chains in osteoporotic bone compared with osteoarthrotic and "normal" bone, whereas the prolyl hydroxylation was nearly unchanged. The lysyl overhydroxylation was observed in the compact as well as in the trabecular bone of osteoporotic femoral heads. These biochemical alterations may play a crucial role in the pathogenesis of osteoporosis.
It has been shown that serum total homocysteine (HC) is a risk factor for vascular disease which characterizes endothelial damage. The incidence of vascular disease is increased in continuous ambulatory peritoneal dialysis (CAPD) patients. Our aim was to investigate: (1) whether concentration of HC correlates with atherosclerotic and inflammatory events, and (2) if fish oil therapy can retard the disturbance in lipid metabolism which promotes atherosclerosis. Fourteen patients with various degrees of impaired peritoneal clearance and lipid metabolism were observed. In all patients the serum HC was elevated. Seven patients were treated with fish oil for three months. The results indicate an average increase of HC (+18%), total cholesterol (+6.6%), aggregation of erythrocytes (+9%), and an average decrease of dialysate-to-plasma creatinine (DIP) ratio (-7%), deformability of erythrocytes (-8%), and normalization of elevated soluble interleukin2 receptor (sIL-2R) values. Regression analysis of all data demonstrated a significant correlation between HC and parameters of lipid metabolism and hemorheology. There were no significant correlations between HC and peritoneal function and serum cytokine levels. We conclude that the treatment in CAPD patients with fish oil did not improve the lipid metabolism disturbances in atherosclerosis and peritoneal function. Elevated HC confirms the progression of the disease.
1H‐N.M.R. Spectroscopic Investigations on Innermolecular Mobility of Substituted Acrylates
The barriers of rotation around the CC‐bond of, ethyl 3‐arylamino‐2‐nitro‐acrylates 1 and ethyl 3‐arylamino‐2‐cyano‐acrylates 2 have been determined by dynamic n.m.r. spectroscopy. From coalescence phenomena the free activation enthalpies ΔG≠ of rotational processes are determined and discussed with respect to substituent effects.
Stereochemical Investigations of Heterocyclic Compounds. XII. Structural Investigations of 1‐(2‐Amino‐1‐cyano‐2‐thio)ethene Pyridinium Ylides
Two isomerization processes were found by 1H‐d‐n. m. r. characterized by ΔG* = 67 ± 4 KJ/mol for E‐ Z‐isomerization and ΔG* = 46 ± 5 KJ/mol for the hindered rotation of the pyridine substituent in 1a. The structure of 1b was solved by direct method. Crystals are monoclinic space group P21/n, a = 13.682(3), b = 9.452(1), C = 19.713(6) Å, β = 96.42(2)°, V = 2533.3 Å3, Dx = 1.328 Mg · m−3, Z = 8. Both E‐ and Z‐isomeres of 2b are found in the crystal lattice. The aminoC distance with 1.369 (1,387) Å is shorter than the theoretical single bond distance. The formal CC double bond with 1.377 (1.391) Å is considerably longer than 1.337 Å observed in the some alkenes.
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