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Biomedical subjects

W Bartmann

Publications and source records attributed to W Bartmann.

14 recordsLinked to original sources
PubMed1998

Monitoring ovarian cycle and pregnancy in the giant anteater (Myrmecophaga tridactyla) by faecal progestagen and oestrogen analysis.

Oestrogen and progestagen metabolites were measured in the faeces of five female giant anteaters (Myrmecophaga tridactyla), to characterise the oestrous cycle and pregnancy. Faecal samples were collected twice weekly for a minimum of 6 months, and immunoreactive progestagens and oestrogens were analysed using enzyme immunoassays (EIA). For progestagens, two antibodies that cross-reacted with 20alpha-hydroxy- or 20-oxo-progestagens were used. Both assays effectively monitored ovarian cyclicity; however, the concentrations obtained using the antibody for 20alpha-hydroxy-progestagens were higher, and the hormonal changes were more pronounced. Regular ovarian cycles were identified in three of the five females. Average (+/-SEM) length of the oestrous cycle (n=10) was 51.4+/-5.6 days. Peak concentrations of 20alpha-hydroxy-progestagens ranged from 80-660 ng/g of faeces and those of oestrogens from 20-100 ng/g. Hormone concentrations were measured during parts of two pregnancies and during four post-partum periods. The length of one gestation (from oestrous oestrogen peak until parturition) was 184 days. In the second half of gestation, progestagen concentration started to increase above luteal phase values; in the week before parturition it was approximately 20 times higher than those during the luteal phase. Concentrations of excreted oestrogens began to increase after two thirds of gestation and exceeded that of the follicular phase by approximately 2.5-fold in the week before parturition. Onset of ovarian cyclicity after parturition varied from 4-11 weeks. In conclusion, the measurement of faecal immunoreactive progestagens and oestrogens in the giant anteater indicated an ovarian cycle of approximately 7 weeks in length and provided potentially useful data for successful breeding management.

Animals↗
PubMed1991

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 3. Lactones of 6-phenoxy-3,5-dihydroxyhexanoic acids.

A group of 43 optically active sodium carboxylates (11a-qq and the corresponding lactones 4 were prepared from respective phenols 8 according to Schemes I-III. Phenols 8 were synthesized from commercially available compounds according to Schemes IV-IX. A number of these HMG-CoA reductase inhibitors 11 exceeded mevinolin's activity in vitro (Tables II and III). Selected lactones 4 effectively inhibited hepatic "de novo" cholesterol synthesis in rats in vivo (Table IV). After po administration to rabbits, 4ff(11ff), 4hh, and notably 11jj reduced plasma cholesterol levels more potently than mevinolin (Table V). Whereas 4ff(11ff) displayed the slight superiority expected according to in vitro data, 4hh and 11jj were considerably more potent than expected. Each of these compounds had only moderate activity after po administration to dogs (Table VI). Compound di-11ii, a hybrid of the structural elements of probucol and HMG-CoA reductase inhibitors, after po administration to rats decreased serum lipoproteins and increased HDL/LDL ratio better than probucol (Table VII). HMG-CoA reductase inhibitor 11ll and phenolic building blocks 8, notably 8jj and 8kk, inhibited LDL oxidation in vitro (Table VIII). Chemical structure-activity relationships (Table IX) and the pharmacological profile of phenoxy-type inhibitors 11 diverged from those of known HMG-CoA reductase inhibitors.

Animals↗
PubMed1990

Synthesis and biological activity of new HMG-CoA reductase inhibitors. 1. Lactones of pyridine- and pyrimidine-substituted 3,5-dihydroxy-6-heptenoic (-heptanoic) acids.

Lactones of pyridine- and pyrimidine-substituted 3,5-dihydroxy-6-heptenoic (-heptanoic) acids 2-4 have been synthesized. Extensive exploration of structure-activity relationships led to several compounds exceeding the inhibitory activity of mevinolin (1b) on HMG-CoA reductase, both in vitro and in vivo. First clinical trials with 2i (HR 780) are in preparation.

Acetates↗
PubMed1988

Synthesis and biological activity of new leukotriene antagonists (racemates and enantiomerically pure compounds).

Two series of structural analogues of leukotrienes C4, D4 and E4 (LTC4, LTD4, LTE4) were prepared. The compounds were evaluated for their ability to antagonize leukotriene-induced contractions of guinea pig lung strips. In comparison to FPL-55712, compounds 1a and 2h were more potent antagonists against LTC4 (2- and 3fold, respectively) and LTD4 (6- and 60fold respectively). Moreover, in vivo compounds 1a and 2h exhibited antagonism against leukotrienes (C4, D4, E4) and PAF, the most potent mediators in bronchial asthma. 2h also showed antagonistic activity when tested by inhalation.

Animals↗
PubMed1980

Antihypertensive activity of 16, 16-dimethyl-oxa-alkyl-prostaglandins of the PGA2, PGE2 and trans-delta 2-11-deoxy-PGE1 series: structure-activity relationships.

Utilizing Corey's synthesis, a variety of prostaglandins (PGs) with a modified omega-side chain were prepared. The 16, 16-dimethyl-oxa-alkyl analogues of PGA2 had potent antihypertensive activity. HR 466 (16, 16-dimethyl-18-oxa-PGA2), the best compound out of this series was active for 5-6 hours after oral administration of 0, 1 mg/kg to conscious renal hypertensive dogs. The corresponding analogues of PGE2 were also potent anti-hypertensive compounds, but were much more spasmogenic. Structural variations within the trans-delta 2-11-deoxy-PGE1-series, in both side chains, gave HR 601 (trans-delta2-15alpha-acetoxy-16, 16-dimethyl-18-oxa-11-deoxy-PGE1-methylester) which was orally active in the hypertensive dog with similar activity to HR 466.

16,16-Dimethylprostaglandin E2↗
PubMed1979

Luteolytic prostaglandins. Synthesis and biological activity.

Analogues of PGF2 alpha with enhanced luteolytic activity were synthesized using the Corey synthesis. The luteolytic activity of the new prostaglandins was tested in the hamster. In addition the smooth muscle activity of the new compounds was compared with that of PGA2 on the longitudinal strip of rat stomach fundus. Structure-activity relationships in the new series of 17,18,19,20-tetranor-16-thienyl-oxy-PGF2 alpha are discussed.

Abortion, Induced↗
PubMed1979

Vasodilation and inhibition of platelet aggregation by prostacyclins with modified omega-side chain.

Prostacyclin analogs with modified omega-side chain were synthetized in search of therapeutically useful agents. To characterize the vasodilator and platelet-antiaggregating properties, prostacyclin analogs were tested on systemic blood pressure in anesthetized rats, relaxation of bovine coronary artery and inhibition of arachidonic acid induced human platelet aggregation. The sodium salt of prostacyclin induced a dose dependent decrease of blood pressure with an ED25 of 0.23 microgram/kg i.v., a marked relaxation of bovine coronary artery with an IC50 of 5.9 ng/ml and a strong inhibition of platelet aggregation with an ED50 of 3x10(-9) M. Similar results were obtained with prostacyclin-methylester. Replacement of the n-pentyl moiety attached to C-15 of prostacyclin by cyclohexyl, 2-(2-furyl)ethyl, 2-(3-thienyl)ethyl and especially by 3-thienyl-oxymethyl yielded analogs with comparable prostacyclin properties, while substitution by 1,1-dimethyloxaalkyl residues was followed by a marked loss of activity. The order of potency among the analogs of the sodium salt and methylester of prostacyclin with strong vasodepressor and antiaggregatory properties was identical in all three models used. The three test systems used for evaluation have demonstrated that suitable modifications of the omega-side chain of prostacyclin result in potent vasodilator and platelet-antiaggregating agents.

Animals↗
PubMed1975

Prostaglandins.

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Abortifacient Agents↗