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Biomedical subjects

J Eckert

Publications and source records attributed to J Eckert.

At least 55 records · Page 3Linked to original sources
PubMed1998

A detailed analysis of pronucleus development in bovine zygotes in vitro: cell-cycle chronology and ultrastructure.

The aim of the present experiment was to analyze the chronology of pronucleus development and DNA synthesis, as well as the ultrastructure of intranuclear bodies, in bovine zygotes produced in vitro. Bovine oocytes were matured and fertilized in vitro, and sperm penetration and pronucleus development were examined. DNA synthesis was investigated by sequential incubation with [3H]- and [14C]thymidine followed by autoradiography on semithin sections. Ultrathin sections for transmission electron microscopy were prepared from the same zygotes. Sperm penetration was noted for the first time at 4 hr after in vitro insemination and reached a maximum at 6 hr. Pronucleus formation was initiated at 4 hr, and up to at least 11 hr the maternal pronucleus was more developed than its paternal counterpart. DNA synthesis was initiated at 14-15 hr, and the S-phase lasted for 8-10 hr. The most prominent ultrastructural entities of the pronuclei were the nucleolus precursor bodies (NPBs). During the S- and G2-phases, the NPBs spatially associated with clusters of interchromatin-like granules. The two components were firmly attached to each other by an electron-dense reticulum. During the late G2-phase, the NPBs were apparently detached from the interchromatin-like granules and the electron-dense reticulum again. The interaction between the intranuclear bodies and granules appears to be comparable with the situation previously described for in vivo-produced bovine zygotes (J Laurincík et al., Mol Reprod Dev 43:62-69, 1996), except for the lack of vacuolization of the NPBs during the S-phase in vitro.

Animals↗
PubMed1998

Long-term mebendazole therapy may be parasitocidal in alveolar echinococcosis.

Long-term chemotherapy of human alveolar echinococcosis with benzimidazole compounds (mebendazole, albendazole) has been shown to be primarily parasitostatic, but its curative (parasitocidal) efficacy is debated. This article reports on a 67-year-old male patient with non-resectable alveolar echinococcosis of the liver who had been continuously treated for 13 years with mebendazole (approximately 45-48 mg/kg body weight per day) and who was closely monitored according to a specific protocol. At the age of 80 years the patient died of oesophageal variceal bleeding. During treatment the hepatic lesion had decreased markedly in size in association with progression of perifocal calcification. At autopsy, a well-demarcated, necrotic, partially calcified, parasite-induced lesion of the right liver lobe and secondary biliary cirrhosis were found. Remnants of parasite tissue obtained from the periphery of the lesion showed a small-cystic structure, but it was not viable, as evidenced by transplantation of tissue blocks to rodents. The case is suggestive for a parasitocidal efficacy of mebendazole treatment carried out for 13 years, and is discussed in context with conflicting literature data.

Aged↗
PubMed1998

Exogenous protein affects developmental competence and metabolic activity of bovine pre-implantation embryos in vitro.

The role of exogenous protein during bovine pre-implantation embryo development in two in vitro production systems was investigated. Morphological development, survival after vitrification and metabolic activity before and after vitrification were recorded in blastocysts generated in vitro in synthetic oviduct fluid (SOF) medium in the presence of either bovine serum albumin (BSA) or polyvinyl-alcohol (PVA). Metabolic activity was determined by measuring oxygen consumption, glucose and pyruvate uptake as well as lactate production. Development to blastocysts and survival after vitrification were reduced significantly in medium lacking protein. Of the metabolic parameters measured, only pyruvate uptake was increased significantly in embryos cultured in medium supplemented with PVA. Whereas in BSA-supplemented medium pyruvate uptake was correlated with lactate production, in PVA-supplemented medium glucose uptake was correlated with lactate production. Lactate production increased significantly after vitrification as compared with fresh embryos. Thus, exogenously added protein significantly alters oxidative metabolism. In medium lacking protein, the additional pyruvate may be used for the maintenance of intracellular amino acid pools. Vitrification appears to alter glycolytic metabolic profiles indicating a stress-response. In conclusion, the perturbed metabolism corresponding to reduced developmental capacity of embryos produced under protein-free conditions emphasizes the ambiguity between maximum development, technical and hygienic requirements and physiological demands of the early bovine embryo in vitro. The use of well-defined recombinant proteins might assist in closing this gap.

Animals↗
PubMed1998

mRNA expression of leukaemia inhibitory factor (LIF) and its receptor subunits glycoprotein 130 and LIF-receptor-beta in bovine embryos derived in vitro or in vivo.

Leukaemia inhibitory factor (LIF) plays an essential role during cell differentiation and implantation in the mouse exerting its effects via the two dimerizing receptor subunits glycoprotein 130 (gp130) and LIF-receptor beta (LR-beta). This study investigated the mRNA expression of bovine LIF (bLIF), gp130 and LR-beta in pooled or individual bovine oocytes and embryos generated in vitro or in vivo after superovulation. Transcripts of gp130 and LR-beta were detectable in as little material as 1/3 oocyte equivalent and bLIF transcripts in two embryo equivalents employing a simple, rapid and robust one-step reverse transcription-polymerase chain reaction (RT-PCR) protocol using random hexamer priming during reverse transcription and 60 amplification cycles in the PCR. All mRNA fragments were also found in cumulus cells and various bovine tissues. While gp130 and LR-beta mRNA were present in pooled material throughout embryo development in vitro from the immature oocyte to the hatched blastocyst, bLIF-transcripts were absent in immature oocytes, inconsistently expressed from the matured oocyte up to the 16-cell stage as well as in blastocysts dependent on embryo batch. It was not found in morulae, but again present in hatched blastocysts. In contrast, in in-vivo derived embryos no bLIF was found, LR-beta was not detected at the morula to blastocyst transition while gp130 transcripts were observed from the morula to the hatched blastocyst. In individual embryos the mRNA expression pattern was similar for both in-vitro and in-vivo derived embryos as found in pooled material. These results indicate perturbation of the mRNA expression pattern of the specific LIF-LIF-receptor system in embryos generated in vitro that could lead to abnormal differentiation of the cell compartments forming the blastocyst. Cumulus cells, frequently used as supportive factor in co-culture in bovine in-vitro embryo production, are a rich source of the LIF-LIF-receptor system acting in a paracrine and/or autocrine manner. The biological function of the LIF-LIF-receptor system during bovine preimplantation development warrants further investigation.

Animals↗
PubMed1997

Veterinary parasitology and human health.

Veterinary parasitology is a subdiscipline of veterinary medicine and is concerned (a) with diseases in animals caused by protozoan and metazoan parasites, (b) with parasitic zoonoses and (c) with parasites acting as disease vectors. Veterinary parasitology is related to human health and well-being in a number of ways. It plays a role in treatment, prevention and control of parasitoses in animals which serve as food sources for humans, which are used in agriculture as farm animals or which are companion animals of humans. Of direct significance to human health are activities of veterinary parasitology in prevention and control of food-, water-, vector-borne and other zoonoses, such as toxoplasmosis, cryptosporidiosis, leishmaniosis, taeniosis/cysticercosis, echinococcosis and others. In this context the evolution of veterinary parasitology, progress in the control of parasitic animal diseases, the concerns of mass-treatment of livestock against parasitoses, environment related problems and other factors are discussed. Finally, examples of current and predictable future research trends in veterinary parasitology are summarized. It is concluded that an innovative veterinary parasitology in cooperation with other disciplines will be in a position to contribute further to the improvement of human health and well-being.

Animal Husbandry↗
PubMed1997

Alternatives to animal experimentation in parasitology.

In parasitology, several measures can contribute to the aims of 3R (Reduction, Refinement and Replacement of animal experimentation). These include legal regulations, international guidelines for evaluating antiparasitic drugs, the refinement of animal models for parasitic infections, cryopreservation and cultivation of parasites in vitro or in chicken eggs, the maintenance of arthropods by artificial feeding, and the use of immunological and molecular in vitro techniques (e.g. the production of recombinant antigens for vaccines). Considerable progress has been achieved in the development of alternative techniques but both their standardisation and validation are not far advanced. A wider acceptance and use of alternative methods will only be achieved if research can offer economic alternatives that are as effective and reliable as animal experiments. Great efforts are needed for further progress.

Animal Testing Alternatives↗
PubMed1997

Intraspecific variation of Echinococcus granulosus and related species with emphasis on their infectivity to humans.

Four species are presently recognised within the genus Echinococcus, namely Echinococcus granulosus, E. multilocularis, E. oligarthrus and E. vogeli, which are infective to humans. Evidence for strain diversity within the species E. granulosus, previously mainly based on morphological, biological and biochemical features, has been principally confirmed by recent genetic studies. Several molecular techniques are now available which allow the identification of E. granulosus strains. Epidemiological evidence and molecular studies indicate that the so-called sheep, cattle and cervid strains of E. granulosus are infective to humans, while the horse, camel and pig strains may be less or not infective, but this question warrants further studies. A recent study indicates that E. granulosus infecting patients in Poland shares close molecular affinity with a genotype of pig origin (G7) but exhibits some clear differences. Therefore, it may represent a previously undescribed genotype of E. granulosus, designated as G9. Phylogenetic analysis of molecular data has demonstrated the need to reappraise the taxonomic status of currently recognised strains. Clear evidence for strain variation in the other species of Echinococcus does not exist at present.

Animals↗
PubMed1997

Comparative reproduction of Cryptosporidium baileyi in embryonated eggs and in chickens.

At 2 days of age, each of 20 chickens was perorally or intracloacally infected with 3 x 10(5) oocysts of Cryptosporidium baileyi and maintained for 13 days post infection. In parallel, 20 embryonated chicken eggs were inoculated with 3 x 10(5) oocysts at day 10 of embryonation and were incubated for a further 7 days. The average reproduction rates in the two groups of chickens were x560 after peroral infection and x533 after intracloacal infection as compared with x256 in the eggs. Although the rate of reproduction of parasites seen in the eggs was only about 50% of that observed in chickens, large numbers of oocysts could be harvested (on average, 77 million per egg versus 161 and 168 million from chickens). Nearly the same number of oocysts could be obtained from two eggs as compared with one chicken. The use of embryonated eggs accommodates the sense of animal-protection regulations, is less expensive, and allows the isolation of oocysts under sterile conditions.

Animals↗
PubMed1997

Fetendo-clip: a fetal endoscopic tracheal clip procedure in a human fetus.

Fetal tracheal occlusion accelerates lung growth and corrects the often fatal pulmonary hypoplasia seen in fetuses with congenital diaphragmatic hernia. Fetoscopy presents a unique opportunity to glimpse into the world of the fetus, but its use, until recently, has been limited to diagnostic and simple procedures. Using fetoscopic techniques ("Fetendo"), we now report successful tracheal occlusion in a 30-week-old fetus for the treatment of congenital diaphragmatic hernia.

Adult↗
PubMed1997

Epidemiological investigation of trichinellosis in Switzerland.

Domestic pigs in Switzerland have been considered Trichinella-free for decades, despite the occurrence of Trichinella in the wildlife cycle. In order to reevaluate the present epidemiological situation, tissue samples from 11226 domestic pigs, 356 wild boars and 452 foxes were examined using the standard artificial digestion method. A simultaneous serological study, extended to include 25239 sera from sows provided by a Swiss pig serum bank, was also undertaken. The results of both studies support the conclusion that Trichinella spp. do not occur within the domestic pig population in Switzerland. Among the fox population, Trichinella was detected in four (0.9%) of the animals tested using the digestion method, and Trichinella britovi was identified as the infecting species by RAPD fingerprint analyses.

Animals↗
PubMed1997

Ratio of inner cell mass and trophoblastic cells in blastocysts derived from porcine 4- and 8-cell embryos and isolated blastomeres cultured in vitro in the presence or absence of protein and human leukemia inhibitory factor.

In this study we investigated effects of developmental stage at onset of individual in vitro culture on the progress of development in intact embryos and individual blastomeres derived from 4-cell and 8-cell porcine embryos (referred to as 1/4 and 1/8, respectively), the necessity of serum or BSA supplementation in culture media for embryos and blastomeres (in contrast to development in a defined medium), and the role of two concentrations of human leukemia inhibitory factor (hLIF) on development of blastomeres and embryos. More (p < 0.05) 1/4 blastomeres developed to the blastocyst stage than did 1/8 blastomeres. In the serum-supplemented medium, the percentage of inner cell mass (ICM)/total cells in 8-cell- and 1/8-derived blastocysts was higher (p < 0.05) than that in 4-cell- and 1/4-derived embryos. Development to blastocysts was similar in BSA-supplemented and defined medium as compared to that in serum-enriched medium in intact 4-cell and 8-cell embryos, and 1/4 blastomeres. More (p < 0.05) 1/8 blastomeres developed to the blastocyst stage in serum-supplemented medium than in defined medium. The high hLIF concentration (1000 IU/ml) decreased (p < 0.05) blastocyst development in 1/4 blastomeres in defined medium, but fewer blastocysts (p > 0.05) lacked an ICM (blastocyst-like vesicles) than in defined medium without hLIF. It is concluded that 1) porcine intact embryos and isolated blastomeres can be cultured individually in defined medium up to the blastocyst stage from the 4-cell stage onwards; 2) more 1/4 isolated blastomeres develop to blastocysts with more total cells but with a lower ratio of ICM to total cells than blastocysts derived from 1/8 blastomeres; 3) the effects of hLIF are dependent on proteins present in the culture medium and on the embryonic stage; and 4) in defined medium, high concentrations of hLIF are inhibitory to blastocyst formation, but fewer blastocyst-like vesicles are formed. The defined culture system employed in this study allows examination of the effects of growth factors or cytokines in porcine early embryonic development.

Animals↗
PubMed1997

Glutamatergic dysfunction in catatonia? Successful treatment of three acute akinetic catatonic patients with the NMDA antagonist amantadine.

Therapeutic efficiacy of the NMDA antagonist amantadine is reported in three acute neuroleptic free akinetic catatonic patients. Intravenous infusion of amantadine led to the resolution of catatonic symptoms and considerable reductions of scores in various motor scales (Simpson Angus scale for extrapyramidal side effects (SEPS), the abnormal involuntary movement scale (AIMS), Rogers catatonia and schizophrenia scales). The therapeutic effect of amantadine showed a characteristic temporal pattern with most pronounced effects four to six hours after administration and recurrence of catatonic symptoms by 24 hours later, at least partially. Such a temporal pattern of therapeutic efficacy and decreasing efficacy occurred in all three patients on all days. The results suggest the central importance of glutamatergic dysfunction in catatonic syndrome.

Adult↗
PubMed1997

[Significance of membership in new religious movements for regulation of self concept exemplified by the Hare Krischna movement].

222 members of the Hare-Krishna-Movement were investigated with the Narcissism Inventory by Deneke and Hilgenstock (1989). The results show that life in the Hare-Krishna-Movement makes certain defensive functions possible. The Hare Krishnas seem to reach a stabilization of their self experience through idealizing transferences and overemphasizing their value-system. High scores on the scale derealisation/depersonalisation hint at an ego-weakness of the members.

Adult↗
PubMed1997

Epidemiology of Echinococcus multilocularis and E. granulosus in central Europe.

Two species of Echinococcus are known to occur in central Europe, namely E. multilocularis and Echinococcus granulosus, causing the alveolar and the cystic form of echinococcosis in humans, respectively. Recent studies have shown that in central Europe E. multilocularis occurs further north, south and east than previously anticipated. This parasite is endemic in Belgium, Luxembourg, France, Switzerland, Liechtenstein, Austria, Germany, Poland, and the Czech Republic. The prevalence rates of E. multilocularis in foxes are alarmingly high in some areas with average rates > 40%. Infection rates in dogs and cats are much lower. In recent years accidental infections with the metacestode stage of E. multilocularis have been observed in various animal species (dog, domestic pig, wild boar, nutria and monkeys) and in humans. The mean annual incidence rates of alveolar echinococcosis in humans are low varying between 0.02 and 1.4 cases per 100,000 inhabitants in several European countries and regions. For monitoring of the infection in final host populations new techniques are now available, notably the coproantigen ELISA and for selected cases also egg detection by the Polymerase Chain Reaction. E. granulosus has an uneven geographical distribution in Europe with very low prevalence rates in some of the northern and central European countries, with medium endemicity in others and high endemicity in areas of southern and eastern Europe. Cystic echinococcosis in humans is still a significant public health problem, predominantly in the Mediterranean area. Up to now five strains of E. granulosus have been identified in central Europe which differ in their life cycles as well as in morphological, biochemical, genetic and some other features. Several molecular techniques are now available which allow the identification of Echinococcus species and certain strains using genetic markers. Epidemiological evidence and molecular studies indicate that the so-called sheep, cattle, and cervid strains of E. granulosus are infective to humans whereas the horse strain may have no or low infectivity. Polish patients were found to be infected with E. granulosus similar to a pig strain.

Animals↗
PubMed1996

Prophylaxis of bovine trichostrongylidosis and dictyocaulosis in the alpine region: comparison of an early and late administration of the oxfendazole pulse release bolus to first year grazing calves.

The effect of the oxfendazole pulse release bolus (OPRB) administered at turnout, in May, or in mid-July on the development of infections with gastrointestinal nematodes and lungworms in first year grazing calves was investigated with three groups of nine animals, all grazing the same pastures in the Swiss midland region. In the calves of Group A (OPRB on 21 May) less than 20 eggs per gram of faeces (e.p.g.) and less than three Dictyocaulus larvae per 10 g (1.p.10 g) of faeces were shed for a period of 126 and 140 days respectively. Towards the end of the grazing period calves of this group excreted significantly higher levels of lungworm larvae (P < 0.05) compared with the other groups. Prior to OPRB administration on 14 July, the calves of Group B developed subclinical infections with trichostrongyles and lungworms which were similar to the untreated control Group C. By 4 weeks after bolus-administration the excretion of trichostrongylid eggs and lungworm larvae declined to levels below 20 e.p.g. and six l.p.10 g respectively. Serum pepsinogen values of the calves of Groups A and B were significantly lower (P < 0.05) compared with the control animals on days 84 and 98 after turnout and reflected mainly subclinical infections. With the exception of one Group A calf developing clinical parasitic gastroenteritis (p.g.e.) at the end of the season, clinical disease was not observed in the treated calves, while seven out of nine control animals grazing on the same pastures exhibited clinical p.g.e. with mean serum pepsinogen values exceeding 4400 mU tyrosine. Calves of Groups A and B gained significantly more weight (P < 0.01) compared with Group C (+36 kg and +41 kg respectively); differences between Groups A and B were not significant. The results indicate that in mixed grazing systems of treated and untreated calves, which are often found in the alpine region, administration of the OPRB in May or July provided good results with respect to performance of the calves. However, late administration of the OPRB has the additional advantage of coverage of the period of higher infection risk with trichostrongyles and lungworms in the late season until stabling, and should therefore be recommended.

Animal Feed↗
PubMed1996

Effects of platelet-derived growth factor (PDGF) on the in vitro production of bovine embryos in protein-free media.

The purpose of our experiments was to explore the effects of platelet-derived growth factor (PDGF)-supplementation at the various steps of in vitro production of bovine embryos using protein-free media. Cumulus-oocyte-complexes (COC) were collected by slicing abattoir ovaries and then dividing the COC into 2 morphological categories. After maturation for 24 h in TCM-199 supplemented with hormones and either 20% estrous cow serum (ECS) or 1 mg/ml polyvinyl-alcohol (PVA), oocytes were co-incubated for 19 h with frozen/thawed spermatozoa from bull of proven fertility. The semen was diluted in Fert-Talp supplemented with heparin, hypotaurine and epinephrine and either 6 mg/ml bovine serum albumin (BSA) or 1 mg/ml PVA. Presumptive zygotes were transferred into embryo culture medium containing either 20% ECS or 1 mg/ml PVA for a total of 10 d. The PDGF was added at concentrations of 1, 10 or 100 ng/ml to the maturation medium (Experiment 1), fertilization medium (Experiment 2) or culture medium from Day 1 on (Experiment 3), respectively, or at 1 ng/ml PDGF to both the fertilization and culture medium from Day 3 on (Experiment 4), with each medium supplemented with PVA. Oocytes/embryos incubated in the absence of PDGF in media supplemented with either ECS or PVA served as controls. An average of 20 COC was incubated in 1 droplet under silicone oil, and each experiment contained 4 to 6 replicates. No significant differences were found among the various concentrations of PDGF, nor did PDGF-supplementation during maturation (Experiment 1) or embryo culture on Day 1 (Experiment 3) significantly affect development of oocytes/embryos (34.7 +/- 3.5 to 40.4 +/- 2.5% morulae, 11.9 +/- 2.4 to 18.8 +/- 2.5% blastocysts; and 23.2 +/- 2.3 to 27.5 +/- 3.4% morulae, 11.5 +/- 2.6 to 12.7 +/- 2.3% blastocysts, respectively; x +/- SEM). In the presence of 10 ng/ml PDGF in the fertilization medium development to morulae and blastocysts was similar to that of the ECS-group, and was higher (P < 0.05) than that of the PVA-control (ECS: 32.1 +/- 4.6 and 13.8 +/- 2.7%; PVA: 17.5 +/- 0.8 and 6.1 +/- 1.3%; PDGF: 30.6 +/- 3.0 and 14.0 +/- 2.2%, respectively). Development to morulae/blastocysts was increased, and was at the same level as in the ECS-group when the fertilization and/or embryo culture medium on Day 3 contained PDGF compared with the PVA-control group (morulae: ECS 25.3 +/- 4.4%, PVA 13.9 +/- 2.2% [P < 0.05], PDGF 16.7 +/- 3.2 to 19.1 +/- 1.1%; blastocysts: ECS 5.3 +/- 2.1%, PVA 5.0 +/- 1.7%, PDGF 7.1 +/- 1.6 to 9.1 +/- 1.7%, respectively). These results indicate that under our laboratory conditions PDGF can elevate low rates of development and the addition of PDGF to the fertilization medium enhances bovine preimplantation embryonic development. Thus, PDGF can be potentially an important factor in a completely defined medium to substitute the effects of serum.

Journal Article↗
PubMed1996

Workshop summary: food safety: meat- and fish-borne zoonoses.

In this workshop, J.P. Dubey (USA), Th. Hiepe (Germany), and P. Deplazes (Switzerland), were invited speakers. The main areas covered were toxoplasmosis, microsporidiosis, trematode infections, taeniosis/cysticercosis and trichinellosis. The public health and economic impact of meat- and fish-borne parasitic zoonoses is considerable in terms of morbidity and even mortality in humans as well as in losses due to reduced productivity in animals and condemnation of parasitised meat and fish. In this context, the increasing demands of consumers for meat and fish free of pathogens and chemical residues has to be considered. Among the parasitic zoonoses some are widespread and frequent, for example toxoplasmosis. About 30-50% of women of child-bearing age are at risk of acquiring the infection during pregnancy with the potential of prenatal infection and severe disease of the foetus. In addition, toxoplasmosis plays an increasing role as an AIDS-associated infection. There are some recent indications that Toxoplasma infections acquired by adults by ingestion of sporulated oocysts may be more pathogenic than cyst-induced infections. In such cases, eye lesions are quite frequent and were previously thought to be predominantly acquired by prenatal infection (J.P. Dubey, USA). Fish- or crustacean-borne trematodes (species of Clonorchis, Opisthorchis, Paragonimus, intestinal flukes) infect about 39 million people, and about 550 millions are at risk (WHO, 1995). Other zoonotic infections are less frequent but may cause severe and lethal diseases, for example Taenia solium cysticercosis.

AIDS-Related Opportunistic Infections↗