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Biomedical subjects

A Madej

Publications and source records attributed to A Madej.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of melatonin implants on plasma concentrations of testosterone, thyroxine and prolactin in the male silver fox (Vulpes vulpes).

Melatonin administration in the form of slow-release implants advanced breeding activity in silver fox males when treatment began in June. Plasma testosterone concentrations were significantly higher in treated animals than in controls from September to November, whereas in February and March they were significantly lower. Plasma prolactin concentrations were significantly reduced immediately following melatonin treatment in June but increased to greater levels than control values and 'peaked' after 7 months. This 'peak' was associated with a rapid decrease in testosterone secretion. The normal seasonal spring rise in prolactin secretion was prevented by melatonin administration. Thyroxine values decreased and were significantly lower after 2 months of melatonin treatment.

Animals↗
PubMed1989

Influence of bovine LH tracer quality on levels of LH in GnRH-treated cows.

Chromatography of 125I-bovine LH (LER-1716-2 and USDA-I-1) by means of anion exchange high performance liquid chromatography (HPLC) revealed two main peaks of radioactivity regardless as to whether or not the tracer was initially purified on cellulose CF11. The content of radioactivity in the first peak tended to increase as the storage time of the bLH preparation, either before or after iodination, increased. The first peak of radioactivity after HPLC fractionation either with or without cellulose adsorption consisted of material with low binding ability to bLH antiserum (6.9% +/- 0.5 and 13.0% +/- 1.0, respectively) and high binding ability to ovine LH alpha antiserum (51.0% +/- 2.7 and 35.2% +/- 3.6, respectively). The average ratio of alpha-subunit immuno-reactivity to 125I-bLH immunoreactivity in this material was 7.4 +/- 0.1 and 2.7 +/- 0.2, respectively (P less than 0.001). Peaks in 125I-bLH radioactivity and 125I-bLH immunoreactivity had different elution times. Radioimmunoassays with tracers obtained from fractions derived from the first radioactive peak after HPLC chromatography (i.e. 125I-bLH-LER-1716-2) both with and without cellulose adsorption, yielded significantly lower mean plasma LH levels in GnRH-treated cows compared with the control tracer routinely purified only on cellulose CF11 (e.g. 5.7 vs. 8.2 micrograms/; 4.6 vs. 8.2 micrograms/l). Plasma LH levels in GnRH-treated cows were significantly (P less than 0.001) lower as measured by radioimmunoassay utilizing 125I-USDA-blH-I-1 tracers than by radioimmunoassays utilizing 125I-blH-LER-1716-2 tracers (i.e. either Y = 0.17 + 0.75X or Y = 1.18 + 0.60X).

Animals↗
PubMed1988

A sensitive microtitre plate enzyme immunoassay of oestradiol-17 beta in the cow and mare.

Microtitre plates were coated with antiserum against oestradiol-17 beta-6-(O-carboxymethyl)-oxime bovine serum albumin raised in sheep. The plasma samples (0.2-1.0 ml) were extracted with peroxide-free diethyl ether prepared daily by treatment with Al2O3. The enzyme conjugate was prepared by coupling oestradiol-17 beta-6-(O-carboxymethyl)-oxime to horse-radish peroxidase. The conjugate was chromatographed on a Sephadex G-25 column. The standard curve ranged from 0.37 to 18.40 fmol/well of oestradiol-17 beta. The amount of oestradiol-17 beta causing a 50% reduction of maximum binding was 4.4 fmol/well. Standards and samples were incubated overnight at 4 degrees C. The conjugate solution was added followed by further incubation for 2 h at 4 degrees C. Tetramethylbenzidine was used as a chromogen, and the optical density was measured at 450 nm. The patterns of oestradiol-17 beta during a normal oestrus cycle in the cow and mare are presented.

Animals↗
PubMed1988

Direct measurement of progesterone in plasma and milk by a simple solid-phase radioimmunoassay.

A rapid method for determination of progesterone in bovine, goat and porcine plasma as well as in bovine milk was evaluated. The method employed was a solid-phase (125)I radioimmunoassay equipped with progesterone standards in human serum and called the Coat-A-Count procedure. The dilution curves of bovine plasma samples with high progesterone content were parallel with the standard curve based on human serum. The relation between measurements of progesterone levels in bovine plasma using the reference extraction method and the direct Coat-A-Count procedure was highly significant, resulting in the linear regression equation Y = 1.06x-0.04. In case of goat and porcine plasma, the direct method yielded higher results than the reference extraction method (Y = 1.37x + 1.38 and Y = 1.69x - 6.47, respectively). Progesterone concentration in bovine whole milk was much higher when measured by the Coat-A-Count procedure than by the reference Farmos kit (Y = 1.59x + 1.51). However, when the same samples were assayed by a modified Coat-A- Count procedure, i.e. progesterone standards from Farmos kit, the values were more or less identical (Y = 0.88x - 0.21).

Journal Article↗
PubMed1987

Urinary levels of estrone sulfate and 11-ketotetranor prostaglandin F metabolite in pregnant guinea pigs given Clophen A50 (polychlorinated biphenyls).

The urinary levels of estrone sulfate and 11-ketotetranor prostaglandin F metabolite (11-ketotetranor PGF metabolite) during gestation in guinea pigs were measured by radioimmunoassays. Vehicle and Clophen A50 (polychlorinated biphenyls)-treated animals were compared. Gestation was arbitrarily divided into four periods, and the mean hormone levels during each period were compared between the two treatment groups. The Clophen A50 treatment (100 mg total, during Days 16-60), which causes fetal death, was correlated to significantly higher levels of estrone sulfate (p less than 0.05) and 11-ketotetranor PGF metabolite (p less than 0.01) during Days 47-60 (Period IV) of gestation.

Animals↗
PubMed1987

Hormonal changes associated with induced late abortions in the mare.

Two mares received PGF-2 alpha twice daily until abortion and 2 mares received a combined treatment with oestradiol benzoate and oxytocin. The mares were about 150 days pregnant. The PG-treated animals aborted after 37 and 61 h, respectively, and the fetuses were expelled in intact fetal membranes. The other 2 mares aborted 13 and 27 h after the first oxytocin injection, respectively, and showed strong uterine contractions and expelled the fetuses in disrupted fetal membranes. Concentrations of 15-ketodihydro-PGF-2 alpha increased both after PG and oxytocin injections and in association with the abortion, but after the PG-induced abortion there was an immediate return to basal levels and after the oxytocin-induced abortion there was a large increase in the concentrations, indicating damage of the uterus. Progesterone and relaxin concentrations followed the placental function and decreased in association with the abortions. Oestrone sulphate values differed in the two groups; the oxytocin-treated animals showed a rapid decrease while the mares treated with PG showed first a marked increase and then a decrease. Concentrations of PMSG appeared to be unaffected by the abortions.

Abortion, Induced↗
PubMed1986

Pattern of immunoreactivity after reverse-phase high performance liquid chromatography of ovine lutropin at different pH.

Unlabelled and radioiodinated ovine lutropin (oLH) was fractionated using reverse-phase high pressure liquid chromatography, employing a 5 micron Spherisorb C18 column. Following chromatography of unlabelled oLH at pH 3.3, 4.3 and 5.3, all eluted fractions were tested by radioimmunoassay of oLH, oLH alpha and oLH beta. Regardless of pH, the material corresponding to the first peak contained only alpha-subunit immunoreactivity. With increasing pH, the oLH alpha, oLH and oLH beta immunoreactivity separated into two groups of fractions. The retention times of the radioiodinated alpha- and beta-subunits of oLH corresponded to those of the first (descending part) and last peaks from unlabelled oLH, respectively. Following chromatography of radioiodinated oLH at pH 3.3, 5.3 and 6.5, all eluted fractions were analyzed using antiserum against either alpha- or beta-subunits of oLH. At pH 3.3 two radioactive peaks were detected: the first corresponded to the fraction with maximum binding to alpha-subunit antiserum, and the second corresponded to the fraction with maximum binding to beta-subunit antiserum. At pH 5.3 and 6.5, maximum radioactivity occurred in conjunction with maximum binding to both antisera. A free alpha-subunit in the radioiodinated oLH was even detected after chromatography at pH 6.5.

Animals↗
PubMed1985

Subunits of bovine lutropin. Hormonal and immunological activity after separation with reversed-phase high-performance liquid chromatography.

By means of reversed-phase high-performance liquid chromatography, we have fractionated bovine lutropin (LH) standard preparations. The highly purified NIAMDD-bLH-4 was fractionated into two components, while the less pure NIH-LH-B9 revealed three distinct peaks. The eluted material was further characterized by in vitro bioassay and by homologous radioimmunoassay for bovine LH, ovine LH-alpha and ovine LH-beta subunits. The material with the shortest retention time possessed almost no LH-activity and showed a displacement curve nearly identical with that of the ovine LH-alpha subunit. The material corresponding to the second peak exhibited 6% of the original LH-activity, and its immunoreactivity was equal to that of the ovine LH-beta subunit. Furthermore, the fractions supposed to contain the alpha and the beta subunits were rechromatographed and their aminoacid contents analyzed. The results show close similarities between the rechromatographed fractions and the pure subunits.

Amino Acids↗
PubMed1985

Peripheral plasma prolactin concentrations during oestrous cycles in different types of primitive gilt.

Plasma prolactin concentrations were determined by radioimmunoassay during oestrous cycles and around the time of oestrus in different types of primitive gilts: Vietnamese, Zlotnicka and wild-boar X domestic pig hybrids. The animals were bled without stress from an indwelling arterial catheter. The following results were obtained: (1) in all gilts the main prolactin peak was observed at Day 15 or 16 of the oestrous cycle; (2) Vietnamese and hybrid gilts showed a second smaller prolactin surge after (Day 2) or before (Day 17) oestrus; (3) base levels of prolactin during the oestrous cycle were 14.8 +/- 0.93 ng/ml (Vietnamese gilts), 13.2 +/- 1.05 ng/ml (Zlotnicka gilts) and 15.6 +/- 2.01 ng/ml (hybrid gilts). The 15-16-day prolactin peaks reached maximum values of 36.4, 43.4 and 56.5 ng/ml respectively.

Animals↗
PubMed1984

Blood levels of 15-keto-13, 14-dihydroprostaglandin F(2alpha) during the postpartum period in primiparous cows.

Plasma levels of the PGF(2alpha) metabolite 15-keto-13, 14-dihydroprostaglandin F(2alpha) were determined postpartum in 51 primiparous Black and White Lowland cows. The highest geometric mean was 1702 pmol/l on day 3 and lowest 190 pmol/l on day 21. It should be noted that variation between animals in the concentration of the metabolite is high. For instance, on days 4, 10, 16 and 22, concentration of metabolite ranged from 775-2500, 209-2450, 45-851 and 30-398 pmol/l, respectively. The duration of the massive postpartum release of PGF(2alpha) could be determined in only 29 cows. Significant correlations were found between the duration of elevated PGF(2alpha) metabolite levels and the time required for completion of uterine involution (r = -0.41, P < 0.05) and between the duration of increased PGF(2alpha) metabolite levels and the interval from parturition to occurrence of the first ovulation followed by a normal luteal phase length (r = -0.37, P < 0.05). The occurrence of the first ovulation followed by a normal luteal phase length in the 29 cows was positively correlated with the time needed for completion of uterine involution (r = 0.54, P < 0.01).

Journal Article↗