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J Kanka

Publications and source records attributed to J Kanka.

At least 37 records · Page 2Linked to original sources
PubMed1996

Nuclear transplantation in pigs: M-phase karyoplast to M-phase cytoplast fusion.

Porcine embryonic fibroblasts in M-phase were isolated from confluent cultures by selective detachment and fused to homologous metaphase II enucleated oocytes. The fusion products were analysed by light and electron microscopy (EM). The fusion treatment, per se, did not induce the disappearance of the maturation promoting factor (MPF) in the cloned embryos and the transferred chromatin remained condensed for up to 10 h. Spontaneous decondensation started after this time and, at about 20 h post-induction of fusion, a single large nucleus was present in the cytoplasm. The prolonged exposure of introduced chromatin to MPF resulted in a total morphological remodelling as assessed by the nucleolar morphology observed by EM in all the specimens.

Animals↗
PubMed1996

[Bilateral adrenocortical adenomas and the pheochromocytoma syndrome].

A 43-year-old man with clinical signs of pheochromocytoma and adrenal adrenal enlargement underwent adrenalectomy. Bilateral adrenocortical adenomas accompanied by a pressure atrophy of surrounding cortex and normal adrenal medulla were found. The tumours exhibited neither immunohistochemical nor ultrastructural signs of medullar differentiation. As the clinical symptoms of pheochromocytoma slowly disappeared during the 18 month-postoperative period we consider the local tumour activity most probably responsible for the pseudopheochromocytoma symptomatology.

Adrenal Cortex Neoplasms↗
PubMed1995

Response of avian nuclei to mammalian maturation promoting factor (MPF).

Chicken blastodermal cells (stage X) were fused to mouse enucleated oocytes with either no or high maturation promoting factor (MPF) activity. High MPF levels always induced premature chromosome condensation (PCC) irrespective of the number of nuclei fused to a single oocyte. When a single blastodermal cell was fused to a single oocyte without MPF activity the nucleus remained intact for up to 3 h and thereafter underwent PCC. A quite different situation was observed after multiple fusion of several blastodermal cells to a single oocyte without MPF activity. Here, the transplanted nuclei remained intact even after prolonged culture but underwent extensive swelling. DNA synthesis was detected in almost all unfused blastodermal cells. However, after the fusion of several blastodermal cells to a single oocyte no DNA synthesis could be detected. These results provide further evidence that MPF is the universal cell-cycle regulator in the animal kingdom. Its activity is blocked (or neutralised) after fusion to several S-phase cells. Interestingly, our results further suggest that DNA synthesis is suppressed in meiotic cytoplasm even in the presence of an intact nuclear envelope.

Animals↗
PubMed1995

Chromosome condensation activity (CCA) in bisected C57BL/6JxCBA mouse oocytes.

Chromosome condensation activity (CCA) has been analysed in C57BL/6Jx CBA mouse oocytes bisected (i) shortly after germinal vesicle breakdown (GVBD), (ii) in metaphase I (MI) and (iii) in metaphase II (MII) into two equal halves (nucleated, enucleated) which were thereafter fused to S- or G2-phase 4-cell-stage mouse blastomeres. In nucleated halves, premature chromosome condensation (PCC) in transplanted nuclei was always induced irrespective of the cell cycle stage of the blastomere, whereas in enucleated halves only G2 nuclei underwent PCC after transplantation. Premature chromosome condensation in S-phase nuclei was induced only in enucleated halves produced shortly after GVBD. Although S-phase nuclei transplanted to MI or MII enucleated halves remained intact, their capacity to synthesize DNA was invariably suppressed. When spindles were destroyed by preincubation of the oocytes in colcemid before bisection, both nucleated and enucleated halves produced at MI or MII induced PCC of both G2- or S-phase nuclei. These results demonstrate that chromosome condensation activity in mammalian oocytes is compartmentalized rather than uniformly distributed across the cell, and that the enucleation of mammalian oocytes before nuclear transplantation may, under some conditions, influence the levels of CCA and subsequent response of introduced nuclei to cytoplasmic factors.

Animals↗
PubMed1995

[Potential carcinogenic factors in cervical intraepithelial neoplasia].

In a group of 22 women with cervical intraepithelial neoplasia and carcinoma of the cervix uteri and in a control group of 37 healthy women, a number of anamnestic and objective data about factors influencing these women and about consequences of such influence were analysed. Statistically significant differences between patients and controls were found in the character of work performed (physical vs. intellectual, p = 0.0312), the presence of stressing factors at the workplace (p = 0.02), a higher number of consumed meals per day in the control group (p = 0.0009), daily consumption of beer in a higher percentage of patients (p = 0.0015), the frequency of sexual intercourse in the last 2-3 months before the diagnosis of disease or examination (higher in controls, p = 0.0164) and subjective rating of sexual life in the fourth decade (better rating in controls, p = 0.0005). No differences were found between patients and controls in the number of sexual partners, the presence of antibodies against HSV-2 and other factors. According to data presented and data in the literature, external environment, some of the characteristics of sexual life and particularly infection with certain types of papillomaviruses have a certain influence on the development of cervical neoplasias.

Female↗
PubMed1994

A reversible block at the G1/S border during cell cycle progression of mouse embryos.

Late 2-cell stage mouse embryos were cultured in M-199 plus 100 micrograms/ml Na pyruvate 25 micrograms/ml gentamycin and 0.3% BSA with or without mimosine (200 microM, 150 microM, 100 microM and 50 microM) for a short (4-5 h) or long (18-20 h) culture period; after drug removal subsequent embryo development was evaluated. Late 2-cell stage mouse embryos treated with mimosine were blocked at the 4-cell stage. Autoradiographic studies show that mimosine inhibits cell cycle progression in mouse embryos at the G1/S boundary. The onset of DNA replication occurs within 15 min of releasing the embryos from mimosine block. Embryos pretreated with mimosine at 200 microM and 150 microM for 4-5 h progress after 3-4 days in culture to hatched blastocyst (71% and 79%, respectively) compared with control (90%). However a longer pretreatment (18-20 h) with mimosine at 200 microM was significantly detrimental to the subsequent developmental progression to hatched blastocyst (2% vs 81%, p < or = 0.05); the proportion of degenerated embryos was significantly increased with mimosine at 200 microM and 150 microM compared with control (57% and 28% vs 4%, p < or = 0.05) after 3-4 days in culture. Preliminary studies with mimosine treatment at 100 microM and 50 microM for 18-20 h show that 70% and 37% of the embryos were blocked at 4-cell stage, respectively. These results indicate that mimosine inhibits cell cycle progress in mouse embryos at the G1/S border and thus induces a reversible arrest in a dose- and time-dependent manner.

Animals↗
PubMed1994

[Correlation of clinical and virologic diagnosis of cervical infection with human papillomaviruses].

The presented investigation is concerned with contemporary diagnostic possibilities of HPV Infection of the Cervix. The authors present the results of virological examinations of 228 female patients in the Centre for Oncological Prevention. The examination was made by hybridization techniques, using probes specific for HPV 6, 11, 16 and 18 and by serological methods where IgG antibodies were assessed against synthetic peptides, corresponding to several HPV epitopes, as antigens. 156 women (68.4%) were virologically positive, 72 (31.6%) were negative. Subsequently the authors investigated the diagnostic accuracy of HPV changes of the cervix by clinical methods, i.e. colposcopy and cytology, as compared with virological methods. On colposcopic examination uncertain--i.e. insignificant--results were recorded in 24.6%, on cytological examination in 19.7%. In patients where these methods gave unequivocal results (either + or-) a correct forecast of the presence of HPV during colposcopic examination was recorded in 71.1%, in cytological examinations in 66.9%. At least one of the clinical methods assessing papilloma virus infection was prognostically correct in 90.4%. From the investigation ensures that prebioptic methods provide the clinician with relatively reliable information on the presence of HPV infection and enable him to select a therapeutic and dispensarization procedure adequate to the finding. However, they cannot replace virological examination among other reasons also because they cannot assess the HPV type.

Colposcopy↗
PubMed1994

Pulpal response to adhesive resin systems applied to acid-etched vital dentin: damp versus dry primer application.

A number of studies have reported that acid etching of dentin is toxic to the cells of the odontoblastic layer and dental pulp. Other studies report that pulpal inflammation is a consequence of bacterial microleakage. The purpose of this study was to observe the degree of pulpal healing after pretreatment of vital dentin prior to placement of All-Bond and Scotch-bond 2 composite resin adhesives. Zinc oxide-eugenol cement and an acidic cement were employed as controls. One hundred twelve Class V nonexposed cavity preparations were placed throughout the dentitions of five healthy adult rhesus monkeys and observed at 3, 25, and 80 days. Various dentinal pretreatment procedures were employed. The All-Bond Universal primer system was placed on air-dried vital dentin in 23 cavities and on damp vital dentin in 27 cavities. Scotchbond 2 was placed as per manufacturer's instructions. All treatment procedures, materials, and times were represented in all animals. Placement of silicate cement resulted in the most severe pulpal responses at all time periods. Stained bacterial profiles in the remaining dentin on the axial walls of inflamed control pulps were associated with severe pulpal inflammation. These results indicate that acid etching of vital dentin does not impair pulpal healing in deep Class V cavities.

Acid Etching, Dental↗
PubMed1993

Onset of RNA synthesis and poly (A) content of early rabbit embryos. Comparison with sheep.

RNA synthesis in 2-32 cell embryos, as assessed by alpha-amanitin-sensitive 3H-uridine incorporation, was first detectable in 4-cell stage rabbit and 8-cell stage sheep embryos. In the rabbit, uridine incorporation was detectable at the 2-cell stage but was unaltered by alpha-amanitin, indicating synthesis of non-polymerase II-dependent RNA species. Initiation of mRNA synthesis as determined by in situ hybridization with 3H-poly (U) probe was first detectable in late 2-cell stage rabbit and 4-cell stage sheep embryos. In the rabbit embryos, nuclear labelling increased from the late 2-cell stage to the 16-cell stage, following a pattern similar to that of 3H-uridine incorporation. In contrast, the intensity of cytoplasmic labelling decreased from the 1- to the 8-cell stage and then increased up to the 32-cell stage. In sheep embryos, nuclear labelling by the poly (U) probe increased from the 4- to the 16-cell stage. It is concluded that initiation of transcription of the embryonic genome (mRNA) can be detected via the current methods used at the 4-cell stage in the rabbit and the 8-cell stage in the sheep.

Amanitins↗
PubMed1993

RNA synthesis in porcine blastomere nuclei introduced into in vitro matured ooplasm.

The objective was to investigate the RNA synthesis in porcine blastomere nuclei upon transplantation into in vitro matured enucleated oocytes. Nuclei from 2- to 8-cell porcine embryos were introduced into the ooplasm of in vitro matured and enucleated porcine oocytes by electrofusion, and the resultant reconstructed embryos were cultured in vitro. Before fusion or at different intervals after this event embryos were incubated with [3H]-uridine, fixed, and histologically processed for autoradiography in order to detect RNA synthesis. About two thirds of the embryos were considered to depict normal development. All blastomeres displayed pronounced RNA synthesis before fusion, at 3 and 9 h after fusion the synthesis decreased or ceased, and at 24-49 h some embryos resumed synthesis at the 1- to 2-cell stage.

Animals↗
PubMed1993

Coincidence of Paget disease of bone and primary hyperparathyroidism.

The coincidence or association of some metabolic bone diseases is known although it occurs rarely. The authors present a very rare association of Paget's bone disease with primary hyperparathyroidism in a 65 year old male with overt Paget's disease of bone since 1985. For during five years the patient was treated symptomatically only. Later he developed a biochemical syndrome suspect from primary hyperparathyroidism with signs of preexisting Paget's disease of bone. The diagnostic and therapeutic approach is presented. After the removal of parathyroid adenoma, laboratory findings depicted recent status of Paget's disease of bone with high activity. Treatment of this disorder was advised and begun. The overproduction of parathyroid hormone in Paget's disease of bone is not usual and the mechanism of overproduction remains often unclear. Some views from literature are presented and discussed. If the parameters of bone metabolism cause doubt about the origin of the bone disease and a possibility of some combination occurs, it must be born in mind that such combinations may exist.

Aged↗
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↗