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Biomedical subjects

M Henkel

Publications and source records attributed to M Henkel.

At least 19 recordsLinked to original sources
PubMed2003

Relatedness and heterogeneity at the near-terminal end of the genome of a parapoxvirus bovis 1 strain (B177) compared with parapoxvirus ovis (Orf virus).

The present study provides for the first time an extended investigation of individual genes located at the near-terminal right end of the genome of parapoxvirus bovis 1, Bovine papular stomatitis virus (BPSV) strain B177 and Orf virus (ORFV). Comparison of the respective DNA sequences of ORFV strain D1701 (9.9 kbp) and BPSV B177 (7.7 kbp) revealed a very similar organization of closely related genes transcribed in a rightward orientation. The most salient findings of this study were: (i) the absence of the ORFV-specific vascular endothelial growth factor (VEGF-E) gene in the BPSV isolate; (ii) the presence of an interleukin-10 (IL-10) orthologue; and (iii) the detection of three new genes encoding ankyrin-repeat-containing polypeptides. These results not only contribute to potential improvements of future molecular differentiation between the parapoxvirus species, but also shed new light on different pathobiologies among parapoxviruses.

Amino Acid Sequence↗
PubMed2001

Aging, phase ordering, and conformal invariance.

In a variety of systems which exhibit aging, the two-time response function scales as R(t,s) approximately s(-1-a)f(t/s). We argue that dynamical scaling can be extended towards conformal invariance, thus obtaining the explicit form of the scaling function f. This quantitative prediction is confirmed in several spin systems, both for T<T(c) (phase ordering) and T = T(c) (nonequilibrium critical dynamics). The 2D and 3D Ising models with Glauber dynamics are studied numerically, while exact results are available for the spherical model with a nonconserved order parameter, both for short-ranged and long-ranged interactions, as well as for the mean-field spherical spin glass.

Journal Article↗
PubMed2001

Anisotropic scaling and generalized conformal invariance at Lifshitz points.

The behaviour of the 3D axial next-nearest-neighbor Ising model at the uniaxial Lifshitz point is studied using Monte Carlo techniques. A new variant of the Wolff cluster algorithm permits the analysis of systems far larger than in previous studies. The Lifshitz point critical exponents are alpha = 0.18(2), beta = 0.238(5), and gamma = 1.36(3). Data for the spin-spin correlation function are shown to be consistent with the explicit scaling function derived from the assumption of local scale invariance, which is a generalization of conformal invariance to the anisotropic scaling at the Lifshitz point.

Journal Article↗
PubMed2001

Critical properties of the reaction-diffusion model 2A-->3A, 2A-->0.

The steady-state phase diagram of the one-dimensional reaction-diffusion model 2A-->3A, 2A-->0 is studied through the non-Hermitian density matrix renormalization group. In the absence of single-particle diffusion the model reduces to the pair-contact process, which has a phase transition in the universality class of directed percolation (DP) and an infinite number of absorbing steady states. When single-particle diffusion is added, the number of absorbing steady states is reduced to 2 and the model no longer shows DP critical behavior. The exponents theta=nu(parallel)/nu(perpendicular) and beta/nu(perpendicular) are calculated numerically. The value of beta/nu(perpendicular) is close to the value of the parity conserving universality class, in spite of the absence of local conservation laws.

Journal Article↗
PubMed2000

Generation of recombinant parapoxviruses: non-essential genes suitable for insertion and expression of foreign genes.

Orf virus (OV) is an epitheliotropic poxvirus and belongs to the genus Parapoxvirus (PPV). PPV, especially OV, is regarded as a promising candidate for an expression vector. Among available live vaccines only strain D1701 represents a highly attenuated OV strain with clearly reduced pathogenicity. Therefore, we started to identify potentially non-essential genes or regions of D1701, which might be suitable for insertion and expression of foreign genes. The present contribution reviews some of the progress using the vegf-e (homologue of the mammalian vascular endothelial growth factor) gene locus for the generation of recombinant D1701. The vegf-e gene of D1701 is dispensable for virus growth in vitro and in vivo, and represents a major virulence determinant of OV. It is shown that foreign genes can be inserted and functionally expressed in the vegf-e locus, also leading to the induction of a specific immune response in the non-permissive host. Furthermore, it is reported that adaptation to VERO cells led to the deletion of three further regions of the OV D1701 genome, which seems to be combined with additional virus attenuation in sheep. Molecular analysis of this OV D1701 variant allows the identification of new, potentially non-essential sites in the viral genome.

Animals↗
PubMed2000

A gelatin sponge implantation model in swine for the determination of local immune reactions.

For in vivo determination of innate and memory immune reactions we have implanted sterile gelatin sponges subcutaneously in swine for the monitoring of the following immunological parameters: 1. Analysis of local cell population phenotypes after vascularization of the gelatin sponges using flow cytometry. 2. Comparative analysis of sponge-infiltrating cells after loading with viral antigen in primed as well as naive animals. 3. Performance of reverse transcription quantitative competitive PCR (RT-qcPCR) for the detection of porcine cytokine mRNA indicative for IFN-gamma, IL-2, IL-4, IL-8 and IL-10. The in vitro analysis, e.g. by re-exposure to viral antigens, allows the determination of cytokine reaction patterns of sponge derived cells, draining lymph node cells as well as PBMC of the same individual. Studies of innate reactions and modulation of cellular infiltration in transplanted gelatin sponges are possible. Functional assays, e.g. cell-mediated cytotoxicity, antigen specific cell proliferation, using sponge-derived cells will provide additional information about the suitability of the model for example in vaccine potency tests.

Animals↗
PubMed1999

Parapoxviruses: potential alternative vectors for directing the immune response in permissive and non-permissive hosts.

Parapoxvirus (PPV) represents a genus of the poxviridae, and particularly PPV ovis (Orf virus, OV) seems to offer several potential advantages for the use of vector vaccine. Therefore, we started to investigate the genome of the highly attenuated OV strain D1701, which was only poorly characterised until now. Due to recombination of non-homologous sequences, part of the right hand end of the D1701 genome was duplicated and translocated to the opposite end of the genome. As a consequence gene deletion had occurred and the inverted terminal repeat region is increased. Results are described to identify viral genes, which are non-essential for virus replication and potentially influence viral pathogenesis, virulence, and host immunity. In more detail, we analysed the expression and functional activity of the OV-specific vascular endothelial growth factor (VEGF) gene homologue. Finally the construction and production of a D1701 mutant lacking the VEGF gene homologue is reported.

Animals↗
PubMed1998

Analysis of genomic rearrangement and subsequent gene deletion of the attenuated Orf virus strain D1701.

The orf virus (OV) strain D1701 belongs to the genetically heterogenous parapoxvirus (PPV) genus of the family Poxviridae. The attenuated OV D1701 has been licensed as a live vaccine against contagious ecthyma in sheep. Detailed knowledge on the genetic structure and organization of this PPV vaccine strain is an important prerequisite to reveal possible genetic mechanisms of PPV attenuation. The present study demonstrates a genomic map of the approximately 158 kbp DNA of OV D1701 established by hybridization studies of cloned restriction fragments covering the complete viral genome. The results show an enlargement of the inverted terminal repeats (ITR) to up to 18 kbp due to recombination between nonhomologous sequences during cell culture adaptation. DNA sequencing of the region adjacent to the ITR junction revealed the absence of one open reading frame designated E2L. In contrast to a transposition-deletion variant of the New Zealand OV strain NZ2 (Fleming et al., 1995) the two genes E3L (a homologue of dUTPase) and G1L neighbouring E2L are retained in OV D1701. DNA and RNA analyses proved the presence of E2L gene in wild-type OV isolated directly from scab material. The data presented indicate that the E2L gene is nonessential for virus replication in vitro and in vivo, and may represent one important viral gene in determining virulence and pathogenesis of OV.

Amino Acid Sequence↗
PubMed1995

[Surgical management of complications of open pelvic injuries].

Open pelvic fractures are rare fractures usually resulting from a severe trauma. Only 4 of 121 patients treated operatively in 1994 for a pelvic trauma showed an open injury. The high lethality is caused by two complications: in the early phase the patient is threatened by bleeding to death and in the following course sepsis determines the lethal outcome. Only an aggressive surgical management prevents or treats such complications. The presented concept comprises in the end the hemipelvectomy and an intensive care management for prophylaxis of septic complications. So the lethality was diminished.

Accidents, Occupational↗
PubMed1994

[Correlation between pulmonary hypertension and portal hypertension--2 case reports of different forms of pre-sinusoidal portal hypertension].

Since its first description in 1951 by Mantz and Craig pulmonary hypertension in combination with portal hypertension has been observed more and more frequently. In a recent prospective study Hadengue et al. reported an incidence of 2%. Thus this simultaneous occurrence can no longer be considered to be coincidental. The etiology remains still unclear. It is most probable that the development is due to vasoactive substances which bypass the liver or which are produced in the lung itself, and which, due to a long-term vasoconstriction, causes irreparable damage to the arterioles and arteries in the lung. Such pulmonary hypertension can develop in the presence of a pre- as well as an intrahepatic block, even when the portal hypertension is partially or completely alleviated by a portosystemic anastomosis. This last circumstance can be illustrated by two cases which were observed by our group. Case A is of particular interest because it is the first documentation of a case of an intrahepatic block due to a (so-called) macronodular transformation of the liver in the absence of portal thrombosis (a so-called NRH: nodular regenerative hyperplasia) in combination with pulmonary hypertension. This type of non-cirrhotic portal hypertension can be associated with micronodular transformation of the liver as well. Post-hepatic blocks or the so-called BUDD-CHIARI Syndrome type appear to carry no risk of development of pulmonary hypertension. It remains unclear which particular etiologies increase susceptibility to later development of pulmonary hypertension.

Adolescent↗