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Biomedical subjects

J Kanka

Publications and source records attributed to J Kanka.

At least 19 recordsLinked to original sources
PubMed1992

Development of pronuclei in pig oocytes activated by a single electric pulse.

Pig oocytes were matured in vitro in a modified M-199 medium for 44 h, subjected to electrical stimulation and scored for activation 6 h later. Sham pulsed oocytes, exposed to electroporation medium and an a.c. field, did not develop the female pronucleus any more frequently than occurs spontaneously (8.3% within 50 h of culture). However, a single d.c. pulse proved extremely efficient in activating pig oocytes. Pulses of 0.75-1.65 kV cm-1 lasting 30 or 100 microseconds activated at least 90% of matured oocytes. The developmental pathway taken by the activated oocytes depended on the parameters of the pulse. The lowest effective stimulation (0.45 and 0.60 kV cm-1 for 30 microseconds) frequently produced oocytes that remained in pre-pronuclear stages of activation (29.4 and 42.3%, respectively). Extrusion of the second polar body and creation of one pronucleus was the most frequent type of activation (in up to 88.2% among the activated oocytes). The strongest stimulations used (1.05-1.65 kV cm-1 for 100 microseconds) often yielded oocytes that failed to extrude the second polar body and formed two or more pronuclei (up to 56.3%). Under optimal stimulation (0.75 kV cm-1), the activated oocytes proceed synchronously to interphase of the first mitotic division. Anaphase II is reached within 30 min and telophase Ii at 1 h after application of the pulse. The second polar body is extruded about 2 h after activation. Well-defined swelling pronuclei were found in oocytes 5-6 h after activation. The relationship between the stage of oocyte maturation and susceptibility to activation was investigated. The period of culture in which the oocytes develop the activation competence (32-36 h of culture) overlapped with the period in which the oocytes complete meiosis (28-38 h). This suggests that ageing in meiotic arrest is not essential for pig oocytes to become activated by electric pulses. Activation of pig oocytes was accompanied by release of cortical granules. In sections of control (metaphase II) oocytes, an average of 7.3 intact cortical granules per 10 microns of overlying cytoplasmic membrane was found. This number dropped to 1.5 in 10 microns within 30 min after the pulse.

Animals↗
PubMed1991

Nuclear transplantation in bovine embryo: fine structural and autoradiographic studies.

Nucleolar fine structure, "blebbing" activity of nuclear envelope, and activation of heterogeneous nuclear RNA (hnRNA) synthesis were studied in bovine reconstructed embryos obtained by electrofusion of a single eight-cell blastomere with an enucleated oocyte. Developmental progress of nucleolar fine structure and hnRNA synthesis are arrested during three cell cycles following fusion. The activation of both appears during the eight-cell stage of the reconstructed embryo, after the same number of cell cycles after fusion as in nonmanipulated bovine embryos after fertilization. "Blebbing" activity of nuclear envelope, which is already absent in original blastomeres, reappears after fusion and continues for the next two cell cycles. From the present results, it can be concluded that the donor nuclei are arrested after fusion in morphology and function. Their reactivation corresponds to the developmental pattern typical for normal bovine embryos.

Animals↗
PubMed1991

Follicle and oocyte growth in early postnatal calves: cytochemical, autoradiographical and electron microscopical studies.

The initiation of oocyte and follicle growth was studied in 1- and 3-d-old calf ovaries using cytochemical, autoradiographical and electron microscopical approaches. Attention was only paid to unilaminar ovarian follicles that were classified into 3 categories: unilaminar flattened (UF), unilaminar flatto-cuboidal (UFC) and unilaminar cuboidal (UC) ovarian follicles when the oocyte was surrounded by 1 layer of flattened, a mixture of flattened and cuboidal and entirely cuboidal follicle cells, respectively. Our findings suggested that oocytes within each of these follicle categories were in different developmental stages. Furthermore, electron microscopic observations revealed that early after birth, oocyte nuclei characteristic of diplotene configuration (aggregation of the nuclear chromatin into moderately electron-dense small patches and fibrillo-granular texture of the nucleolus) were encountered in 41% of the UF follicles. The rest of the UF as well as all of the UFC and UC follicles were found to contain dictyate oocytes in which the chromatin was highly decondensed and the nucleolus differentiated into fibrillar, fibrillo-granular and granular components. The present results also indicated that the complete transition of the surrounding follicle cells from flattened to cuboidal shape and the morphological changes of the oocyte endoplasmic reticulum and mitochondria were 2 complementary events essential for initiation of oocyte growth.

Animals↗
PubMed1991

Comparison of ELISA and western blotting for human papillomavirus type 16 E7 antibody determination.

A total of 140 sera originating from healthy women and women with either cervical intraepithelial neoplasia or cervical cancer were tested for the presence of IgG antibody against E7 of human papillomavirus type 16 (HPV-16) by ELISA using a synthetic icosapeptide, denoted 16/E7-2, representing amino acids 11 to 30, and by Western blotting (WB) using a genetically engineered HPV-16 E7 fusion protein. Eighteen sera were found positive in either one or the other test. Positive reactions were more frequently detected in cervical carcinoma patients (12 of 34, 35.2%) than in the other individuals (six of 106, 5.7%). Ten children's (1 to 3 years of age) sera reacted in neither ELISA nor WB with HPV-16 E7. A high degree of concordance between the two tests was found suggesting that both tests detect the same or similar activity. To locate the reacting epitopes in the E7 protein, absorption tests were performed with peptides corresponding to various sections of the protein. Based on the results obtained, sera possessing antibody to HPV-16 E7 could be differentiated into those reactive with only the 16/E7-2 peptide and those reactive with other HPV-16 E7 epitopes.

Adult↗
PubMed1990

[Is it possible to predict the development of Nelson's syndrome in Cushing's disease after bilateral adrenalectomy?].

A detailed analysis of clinical and laboratory findings in a group of 66 patients with Cushing's disease treated with bilateral adrenalectomy, out of whom 15 developed Nelson's syndrome, gave evidence that Nelson's syndrome mostly affects children and young patients compared to older persons. Bilateral adrenalectomy performed in patients aged over 40 years was never accompanied by Nelson's syndrome. Basal plasma ACTH values prior to adrenalectomy (30.9 +/- 4.53 pmol/l in the absence of Nelson's syndrome and 31.3 +/- 5.41 pmol/l in patients with Nelson's syndrome) as well as the degree of their suppressibility with 8 mg dexamethane (to 18.8 +/- 3.43 pmol/l in Nelson's syndrome and 19.0 +/- 3.44 pmol/l in patients without it) did not provide sufficient evidence for the prediction of later development of Nelson's syndrome. The same is true of the plasma cortisol concentrations. A tendency to a significant plasma ACTH increase after adrenalectomy within a 6-month period, and especially its lesser suppressibility raises a strong suspicion of an incipient development of Nelson's syndrome. These findings will have to be taken into account when deciding on the surgical treatment of Cushing's disease.

Adolescent↗
PubMed1989

Genome reactivation in developing early pig embryos: an ultrastructural and autoradiographic analysis.

The onset of RNA synthesis in developing early pig embryos from 1-cell to 8-cell and morula stages was studied using high-resolution autoradiography of (5-3H)uridine incorporation. No transcriptional activity was detected in nuclei of 1- and 2-cell stage embryos with this technique. In these embryos nucleolus-like bodies (NLB) consist of sharply delineated, round, electron dense fibrillar masses. In the 4-cell stage embryos, the first uridine-3H incorporation in the nucleoplasm was detected and localized mainly near the regions of condensed chromatin. The first signs of reticulation and chromatin association were observed at the periphery of NLBs. In the next cell cycle (5- to 8-cell embryos) uridine-3H labelling was detected in the nucleoplasm and nucleoli. In these embryos, nucleoli consist of a central dense fibrillar mass without any transcriptional activity and fibrillo-granular cortex over which label was localized. The degree of functional restructure of nucleoli was variable within one blastomere or among different blastomeres, some nucleoli being more reticulated and showing more transcriptional activity than others. Fully developed nucleoli were present in early morulae. Electron dense unidentified structures described here as small dense round-shaped bodies (RDB) often surrounded by blocks of large chromatin granules were observed in intact 2-cell and alpha-amanitin treated 4-cell stage embryos. These structures did not show any transcriptional activity.

Animals↗
PubMed1989

The application of plasma tartrate-resistant acid phosphatase to assess changes in bone resorption in response to artificial menopause and its treatment with estrogen or norethisterone.

Plasma tartrate-resistant acid phosphatase (TR ACP), urinary hydroxyproline excretion (UH), serum osteocalcin, and bone alkaline phosphatase isozyme were determined in a prospective study in 31 women who had undergone bilateral ovariectomy (OOX). Nine patients were followed up for 1 year without treatment and for the following 3 years when on mestranol (M) substitution. On the basis of UH, 22 patients were identified as having increased bone resorption (BR) within 3 months of OOX. Subsequently, 11 patients were treated with transdermal estradiol (E2) and 11 patients with norethisterone (norethindrone, NE). In untreated patients, the biochemical indices of BR peaked 3-6 months following OOX and biochemical indices of bone formation (BF) continued to increase from 3 until 12 months. The substitution with both E2 or M resulted in normalization in serum and urinary calcium, serum phosphate, renal threshold phosphate concentration (TmPO4/GRF), and biochemical indices of BR within 4 months of treatment. Biochemical indices of BF normalized within 6 months of treatment. In the M-treated group, these effects continued for 3 years of the follow-up. The hormonal substitution had a protective effect on cortical and lumbar spine bone mass. A significant decrease, but not to normal values, in biochemical indices of BR and a persistent elevation in indices of BF were found in NE-treated patients. Unlike E2, NE does not depress osteoblastic function. There is strong evidence supporting the utility of measurements of TR ACP in plasma in examination of women who had ovariectomies and in assessement of the efficacy of treatment.

Acid Phosphatase↗
PubMed1989

In vitro techniques of bovine oocyte maturation, fertilization and embryo culture resulting in the birth of a calf.

Oocyte cumulus complexes were aspirated from 3 to 5 mm follicles of cows prestimulated with 2.000 IU PMSG 24 h before slaughter. Oocytes matured in culture were fertilized in vitro by heparinized freshly ejaculated or epididymal spermatozoa. The cultivation procedure for fertilized eggs was the same as that used for cultivation of oocytes. From 163 matured oocytes, 109 cleaved to the 2-cell stage 24 h after fertilization and after 6 days of cultivation, 18 developed to the late morula and 18 to the blastocyst stages. Eleven blastocyts and 1 late morula were transferred surgically to the uteri of 7 recipient heifers. Two heifers became pregnant: one delivered a bull-calf at term, while the other pregnancy resulted in abortion at the 3rd month. The examination of some embryos by transmission electron microscopy showed an almost normal morphology for most cells. The degenerated cells contained mostly electron-dense residual bodies of unknown origin.

Animals↗
PubMed1989

[Transdermal estradiol in the prevention of the menopause-induced increase in osteoresorption].

In the introduction of the paper the authors explain that it is essential to adopt effective preventive provisions to prevent the loss of osseous tissue in women after the menopause and to prevent osteoporotic fractures. In Bohemia and Moravia during the last 20 years the incidence of these frequently fatal or invalidating fractures of the proximal femur has increased substantially and in view of the ageing of the population it may be assumed that this trend will proceed further. Among possible preventive provisions, in order to eliminate undesirable metabolic side-effects of long-term hormonal substitution treatment, it seems best to administer by the parenteral route natural oestradiol by using the transdermal therapeutic Estraderm TTS system. Its effectiveness in suppressing menopause-induced enhanced bone resorption was tested in 11 women where on average within three months after bilateral ovariectomy increased bone resorption was found. In all women in the course of four months treatment all biochemical indicators of bone remodelling became normal - urinary excretion of hydroxyproline, acid plasma phosphatase activity, serum alkaline phosphatase isoenzyme, and serum osteocalcin. The dynamics of indicators of osteoresorption were similar as in women treated with oral synthetic oestrogen, which may produce, however, serious metabolic side-effects. Substitution treatment with Estraderm improves significantly also other manifestations of the climacteric oestrogen deficiency syndrome. Its safety is further enhanced by combination with progesterone.

Administration, Cutaneous↗