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Biomedical subjects

J Mazur

Publications and source records attributed to J Mazur.

79 records · Page 5Linked to original sources
PubMedDate not supplied

[Conformational effects of DNA stretching].

DNA is an extensible molecule, and an extended conformation of DNA is involved in some biological processes. We have examined the effect of elongation stress on the conformational properties of DNA base pairs by conformational analysis. The calculations show that stretching does significantly affect the conformational properties and flexibilities of base pairs. In particular, we have found that the propeller twist in base pairs reverses its sign upon stretching. The energy profile analysis indicates that electrostatic interactions make a major contribution to the stabilization of the positive-propeller-twist configuration in stretched DNA. This stretching also results in a monotonic decrease in the helical twist angle, tending to unwind the double helix. Fluctuations in most variables initially increase upon stretching, because of unstacking of base pairs, but then the fluctuations decrease as DNA is stretched further, owing to the formation of specific interactions between base pairs induced by the positive propeller twist. Thus, the stretching of DNA has particularly significant effects upon DNA flexibility. These changes in both the conformation and flexibility of base pairs probably have a role in functional interactions with proteins.

Base Pairing↗
PubMedDate not supplied

Comparative studies on the amino acid derivatives of indometacin.

A series of amino acid derivatives of indometacin (IND) was investigated in regard to their protein binding and prostaglandin synthetase inhibition in vitro, and to acute toxicity, anti-inflammatory, antiedemic, analgesic actions, and the influence on the central nervous system in vivo. In biochemical tests the compounds were several times less potent than IND. They differed among themselves in the respect of toxicity, which was always much lower than that of IND. Out of eight compounds investigated N-IND-glycine (K1) and N-IND-epsilon-aminocaproic acid (K5) exerted more favorable antiedemic and analgesic action than IND did. Both the derivatives only weakly inhibited the cotton-pellet granuloma formation. K1 acted similarly to IND in the arthritis test. K1, K5 and IND similarly irritated the gastric mucosa. A modification of IND structure by introduction of glycine or epsilon-aminocaproic acid resulted in two new anti-inflammatory agents of more favorable therapeutic index in the antiedemic and analgesic action and of much lower toxicity than the reference compound.

Amino Acids↗
PubMedDate not supplied

Synthesis and some biological properties of 2-xanthonylalkyl-(alkoxy) carboxylic acids.

2-Xanthonylacetic acids 5a-5d and alpha-methyl-2-xanthonyloxyacetic acid 8 were obtained as potential anti-inflammatory compounds. Preliminary evaluation was carried out for anti-inflammatory and analgesic activity of acids 5a, 5c and 5d and for inhibition of blood platelets aggregation by compounds 5a-5d and 8. In the inhibition of carrageenin-induced rat edema the highest activity shown by acids 5a and 5c was similar to that of ketoprofen.

Animals↗
PubMedDate not supplied

Hypogonadotropic hypogonadism from osteopetrosis.

A 47-year-old man with acquired hypogonadism of at least 15 years' duration was successfully treated with chorionic gonadotropin. Endocrine studies performed before and two months after discontinuation of gonadotropin therapy showed a decrease in serum testosterone level without secondary rise in serum gonadotropins. Testing for the release of other pituitary hormones, TSH, ACTH, HGH and prolactin, showed normal results. Radiographic evaluation of the sella turcica demonstrated a decrease in sellar size with increase in bone density. A bone survey showed that the increase in bone density was generalized. Thickening and disorganization of the bony trabeculae was seen in a biopsy of bone from the iliac crest. The patient described here represents a transitional variety between the infantile and adult forms of osteopetrosis. It is suggested that encroachment of the pituitary gland by the osteopetrotic bone produced the hypogonadotropic hypogonadism of this patient.

Adult↗