Biomedical subjects
Publications and source records attributed to M Hájková.
1. Fowl spermatozoa incubated with DNA were used for the fertilisation of zona-free hamster oocytes. 2. Two categories of spermatozoa were detected: those which were not labelled and those which showed a very high degree of labelling (19 +/- 2% of the whole population). 3. In the hamster oocytes exposed to treated spermatozoa the labelled sperm heads were identified.
Bovine in vitro matured oocytes were parthenogenetically activated by a single pulse of direct current. Suppression of second polar body extrusion by 60 V DC-pulse followed by cytochalasin B treatment or 240 V DC-pulse were used to diploidize parthenogenones. Analysis of the cytological events 20 h postactivation clearly documented high efficiency of both diploidization techniques. All oocytes exposed to a single 60 V DC-pulse and then to cytochalasin B for 3 to 6 h were activated and 70% to 88% possessed two pronuclei. Exposure to 240-V DC-pulse for 10 and 20 microseconds activated all oocytes, 72% and 62% formed two pronuclei, but a high incidence (22% and 30%) of degenerated oocytes was observed. Prolonged in vitro culture of oocytes after parthenogenetic activation and diploidization treatment showed that formed pronuclei were able to fuse and single prometaphase to telophase mitotic cleavage figures developed in all oocytes fixed 28 h after activation, except one cytochalasin B-treated oocyte with two prometaphase sets of chromosomes.
Tubal cumulus-free oocytes recovered from C57BL/6J and BALB/c mice 16 to 24 h after hCG injection were parthenogenetically activated by a single DC-pulse of different voltage. The efficiency of activation was assessed 2, 4 and 24 h after electric stimulation according to the proportion of oocytes with second polar bodies, presence of pronuclei and development of parthenogenetic 2-cell embryos. The best results, 99% and 100% of oocytes with second polar body (2 h) or with second polar body and one pronucleus (4 h), were recorded when oocytes of both strains were activated by a single 60 V DC-pulse (30 microseconds) 20 h after hCG injection. Aging of oocytes or higher voltage of DC-pulse (120 V and 240 V) resulted in both strains in an increase of abnormal oocytes and oocytes with two pronuclei. While a large proportion of activated C57BL/6J oocytes were totally fragmented within 24 h and only 23% reached 2-cell stage, 78% of the activated BALB/c oocytes developed to parthenogenetic 2-cell embryos. It was shown that pronuclear oocytes and parthenogenetic 2-cell embryos for preparation of different types of cytoplasts could be effectively prepared by electric stimulation of tubal oocytes.
Methods for the detection of mycoplasmas in cell cultures with 6MPDR are rapid and inexpensive and do not require special skill in the mycoplasma culturing. Properties of L6M, a dry, lyophilised, sterilised, and thermostabile reagent containing 6MPDR, are described. Its diagnostic value is comparable to that of the liquid, 6MPDR containing reagent MycoTect requiring storage at -70 degrees C.
Bovine follicular oocytes cultured in vitro for 26-27 h were exposed to AC/DC cycle. Mature and immature oocytes were effectively parthenogenetically activated by a single DC-pulse of a different voltage. Application of AC/DC cycle with 60 V DC-pulse (30 microseconds) resulted in 96% of activated mature and 94% of activated immature oocytes. The high activation rate was also recorded when oocytes were treated with higher voltage. The exposure of oocytes to 120 V and 240 V pulses increased the number of degenerated oocytes (6% to 46%) and incidence of oocytes with two pronuclei. The resumption of meioses was observed in 92% of mature and 88% of immature oocytes 1 h after DC-pulse and pronuclei formation was recorded in 72% of mature and 40% of immature oocytes after 6 h of IVC. Two-cell stage parthenogenones were obtained after prolonged IVC (22%) or after transfer into mouse oviducts for 44 h (61%). Possible use of parthenogenetic pronuclear oocytes and 2-cell parthenogenones in pronuclear/nuclear microinjection and nuclear transplantation experiments is outlined.
Knowledge on the response and adaptation of the human organism to motor activity in dependence on age and sex is presented. In organizing substitute motor activities for the population, two lines have to be differentiated, i.e. programs of exercises for the maintenance of health and training for increasing physical fitness. Recent methods of functional diagnosis of aerobic and anaerobic abilities in the laboratory and in sports premises are described. Echocardiographic examination presents a contribution as it enables to study dynamically the adaptation of the heart to different motor activities. The authors formulate their standpoint concerning selection of locomotively talented youth as well as some specific health problems of top performance sports (immunological resistance, doping).
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Detection of the antibodies to the species Mycoplasma bovis in the serum and milk of dairy cows coming from a mastitis-infected herd is a good example of utilization of the ELISA immunoenzymologic method in the mycoplasmology. Examining the samples from 75 dairy cows and applying the indirect hemagglutination test, good correlation of the results of the two tests was determined. The antibodies to the species Ureaplasma diversum were demonstrated by the ELISA method both in the bovine serum and in the milk of dairy cows infected slightly with mastitis. We chosen that strain which detected the maximum titres in the selected samples of the sera out of four antigens prepared from various strains of U. diversum. Rabbit sera hyperimmune to 26 strains of the mycoplasmas of various species were used to identify two antigens (after removing the antibodies to the components of the media). Specific reaction was obtained with the antisera to M. hyorhinis and M. arginini.
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By the mycoplasmic examination of 143 dairy cows exhibiting clinical signs of mastitis, Mycoplasma californicum and M. bovigenitalium were detected as the causal agents of the disease at two localities. The occurrence of specific antibodies in milk, and/or blood serum, was characteristic of the course of the disease, as documented by the results of the examination of more than 300 samples. In some milk samples taken from cows suffering from mastitis of obscure etiology and obtained from State Veterinary Institutes, antibodies to some of the five species of bovine Mycoplasma involved in the disease were found at 22 localities. The antibodies were detected by means of the indirect haemagglutination test and ELISA method. Both these tests are suitable for such an examination, as indicated by the comparison of the results.
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Six cows were inoculated into the mammary gland with eight mycoplasma strains isolated from the genital tract of bulls and two type strains. The milk of cows infected with Mycoplasma bovigenitalium strains isolated from the genital tracts of bulls showed a change in the appearance and contained large quantities of mycoplasmas and specific antibodies. The mastitis was most intense in about 9 days and began to subside in 17 days infection. The type strain of M. bovigenitalium PG11 failed to produce mastitis. On the other hand, the type strain of M. bovis PG45 produced severe mastitis after a 14-day latency period, with the infection spreading to the uninoculated quarters, causing atrophy of the mammary gland, and persisting till slaughter. The sera of all cows that developed mastitis after experimental infection contained high titres of specific antibodies. The two infecting mycoplasma species were recovered from the inner organs and mammary glands of these cows after slaughter.
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