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Biomedical subjects

M Zeman

Publications and source records attributed to M Zeman.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Sexual development and levels of plasma testosterone in the light type of cockerel].

The concentration of testosterone in blood plasma during the ontogenetic development of cockerels was studied in relation to the development of spermatogenic part of gonads. On the basis of the results, sexual development of cockerels can be divided into three stages. The first stage (from hatching to the age of eight to nine weeks) was characterized by a slow increase in gonad weight, by low concentration of plasma testosterone (0.4-2.0 nmol/l) and by the occurrence of spermatogonia in testes. In the course of the second stage (from the age of nine to 16 weeks) a rapid increase in the weight of testes and testosterone concentration was observed. At the end of this stage all phases of spermatogenic cycle were observed in gonads; the testosterone levels averaged to 10 nmol/l. In the course of this stage all cockerels reached sexual maturity; large individual differences in spermatogenesis development were observed. The third stage (16 weeks of age and more) was characterized by an intensive spermatogenesis, further increase in gonad weight and by typical variations of the plasma testosterone levels. The concentration of the circulating testosterone increased before the onset of the final stages of the spermatogenic cycle.

Animals↗
PubMed1983

[The relation between the concentration of testosterone in seminal plasma and certain indicators of reproduction in roosters].

Testosterone concentrations in the semen plasma of the cocks of the laying type were analyzed. The levels in semen plasma were substantially lower than in peripheral blood and were found at the interval of 1.58 to 13.30 nmol . 1(-1), the average values amounted to 5.5 nmol . 1(-1). At the repeated samplings of the same animals, considerable variability of hormone levels was observed, which suggested a possibility of the pulsation character of the changes in the androgen also in this biological material. The correlation coefficients between the testosterone levels in semen plasma and ejaculate volume, as well as between the sperm concentration were positive, however, statistically insignificant. The relation between testosterone and the weight of testes was at the significance limit.

Animals↗
PubMed1982

[Concentration of plasma testosterone in adult roosters of a low-weight strain].

The levels of blood-plasma testosterone were studied in the adult light bodied strain cocks. Blood was sampled (1 ml) from the wing vein by means of a heparinized syringe six times within a 24-hour interval. The plasma obtained by centrifugation was kept in a refrigerator at a temperature of --18 degrees C. Testosterone was determined by the radioimmunological method. The testosterone levels were significantly higher (P less than 0.001), 18.8 nmol/l on the average, in the blood samples taken during the dark period of the day (10 o'clock p.m., 2 and 6 o'clock a.m.) than in the samples taken in the light part of the day (8 and 10 o'clock a.m., 2 o'clock p.m.) when the average concentration of the studied hormone was 10.7 nmol/l of plasma. the lowest levels of testosterone were recorded in the morning and the highest values were recorded late in the evening (10 o'clock p.m.). The differences in the levels of the hormone between sampling terms indicate that the testosterone level in adult animals shows diurnal variances. It was found by the study of the concentration of testosterone in the blood plasma of the same individuals within short intervals of time (30-60 min) that testosterone secretion in adult cocks had a pulsatory manner. The evaluation of hormone levels should include not only the diurnal variances but also the pulsatory manner of testosterone secretion.

Animals↗
PubMed1976

[Infective situation in a cow barn contaminated with Klebsiella mastitis].

The infection situation in a four-row cow-house for 153 animals with a frequent occurrence of Klebsiella mastitis was subject to a detailed analysis. The following results were obtained after two collections of blood and udder-quarter milk samples examined by the test-tube agglutination, gel precipitation, and bacteriological diagnosis methods: 1. Streptococcus agalactiae was isolated from milk samples 28 and 31 times, Pseudomonas aeruginosa 15 and 19 times, Staphylococcus arueus 16 and 19 times, Klebsiella pneumoniae 6 and 6 times, Acinetobacter calcoaceticus once and 4 times, Enterobacter aerogenes twice and three times, and Escherichia coli twice. The authors failed to determine the causative agent in 26--38 cows (20--30%) with a pathologically changed secretion. 2. Double test-tube agglutination performed in a 30-day interval revealed suspected Klebsiella antibodies having a titre of 80 + + and higher in 13 dairy cows (12%); However, the suspicion was disproved by the negative results of gel precipitation. 3. The final deduction concerning the exogenic character of Klebsiella mastitis should encourage efforts for good housing, due nutrition, efficacious disinfection, and hygienic milk production.

Animals↗