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Biomedical subjects

C Jakob

Publications and source records attributed to C Jakob.

28 records · Page 2Linked to original sources
PubMed2000

Crystal structure and mutagenic analysis of the inhibitor-of-apoptosis protein survivin.

The coupling of apoptosis (programmed cell death) to the cell division cycle is essential for homeostasis and genomic integrity. Here, we report the crystal structure of survivin, an inhibitor of apoptosis, which has been implicated in both control of cell death and regulation of cell division. In addition to a conserved N-terminal Zn finger baculovirus IAP repeat, survivin forms a dimer through a symmetric interaction with an intermolecularly bound Zn atom located along the molecular dyad axis. The interaction of the dimer-related C-terminal alpha helices forms an extended surface of approximately 70 A in length. Mutagenesis analysis revealed that survivin dimerization and an extended negatively charged surface surrounding Asp-71 are required to counteract apoptosis and preserve ploidy. These findings may provide a structural basis for a dual role of survivin in inhibition of apoptosis and regulation of cell division.

Amino Acid Motifs↗
PubMed1999

Consensus polymerase chain reaction and enzyme-linked immunosorbent assay for human papillomavirus detection and typing in cervical specimens.

Human papillomavirus (HPV) infection is common in cervical intraepithelial neoplasia (CIN). This study investigates HPV detection and typing assay based on polymerase chain reaction amplification of L1 open reading frame with general primers GP5/GP6, followed by enzyme-linked immunosorbent assay detection with type-specific DNA probes. To determine the sensitivity of this assay, formalin-fixed CaSki cells were used as reference cell lines. Fifty copies of viral DNA diluted in DNA from 100,000 noninfected cells could be detected. This assay was also investigated for HPV detection and typing of 67 cervical specimens diagnosed with with CIN III or carcinoma in situ (CIS) and their adjacent squamous epithelium. The CIN III lesions were infected in approximately 80% of the samples, 81% in the neighboring CIN II, and 68% in CIN I. The HPV infection was even detectable in 54% of nondysplastic epithelium located near a CIN III lesion.

Base Sequence↗
PubMed1996

[Reproductive medicine in transition: new developments in embryo transfer].

Successful application of embryo transfer (ET) has become common practice in cattle, horses, sheep, goats and a variety of other species held in captivity. Yet in cattle only has the technique been established commercially. In 1994 more than 100,000 bovine embryos have been transferred in European countries. Important progress in transvaginal ovum pick up (OPU), in vitro production (IVP) and cryopreservation have further improved the applicability of ET. Direct transfer simplifies the procedure considerably allowing individual transfers and eliminating the need of synchronizing recipients. In Switzerland the organization 'Veterinary Society for Embryo Transfer' (TIGET) has been founded in 1995 to support practitioners performing embryo transfer.

Animals↗
PubMed1995

Studies on human porin: XIII. The type-1 VDAC 'porin 31HL' biotinylated at the plasmalemma of trypan blue excluding human B lymphocytes.

In 1989, we demonstrated for the first time the expression of the VDAC 'Porin 31HL' in the plasmalemma of human B lymphocytes, then giving first evidence of a multi-topological expression of VDAC. Meanwhile, data from this and other laboratories support our proposal of a multi-compartment distribution of the channel in mammalian tissues. Here, by biotinylation of plasmalemma-integrated proteins of proven living B lymphocytes, followed by two-dimensional electrophoresis, immuno- and streptavidin affinity blotting, we show that part of the channel molecules can be labelled at the outer membrane of the cells. Thus, by a relevant approach our results invalidate objections concerning putative cross-reactivity of anti-human Type-1 porin antibodies with non-VDAC proteins at the outer cell membrane.

B-Lymphocytes↗
PubMed1995

The boundary effect in magnetic stimulation. Analysis at the peripheral nerve.

The optimal stimulus position for a figure-8-shaped coil for magnetic stimulation of the ulnar nerve at the wrist was not coincident with the optimal electrical stimulus point but was shifted 18.3 mm to the ulnar side (P < 0.01). For the median nerve the optimal stimulus site was 9.6 mm radial to the optimal position for electrical stimulation (P < 0.05). This shift of the stimulus point for magnetic stimulation is significantly smaller after interposition of a homogenous electrically conducting medium between coil and arm but not changed after interposition of distilled water. This so-called boundary effect is therefore due to the different conductivities of the medium interposed between coil and nerve. It may also distort precise localisation of other excitable structures such as cranial nerves, nerve roots and cortical areas by means of magnetic stimuli. The amplitudes of the compound muscle action potentials elicited with identical magnetic stimulus strength were larger after the interposition of isotonic solution between coil and skin but not after interposition of distilled water. Consideration of the boundary effect provided an improved response amplitude to magnetic stimulation, but this could not adequately compensate for its poor localisation compared to electrical stimulation.

Adult↗
PubMed1993

Self-generated rapid taps directed to the opposite forearm in man: anticipatory reduction in the muscle activity of the target arm.

A brief hammer tap applied passively (by the experimenter) to the forearm elicits a short-latency reflex response in the forearm flexors and extensors. When the same tap is performed actively (by the subject) using the opposite forearm, the reflex response is preceded by a short-lasting anticipatory reduction in the muscle activity appearing around the impact. This anticipatory reduction is interpreted as an alternative mode of feedforward motor control associated with damping of kinetic impulses generated within the bimanual system.

Electromyography↗
PubMed1993

Artifact reduction in magnetic stimulation.

A new biopotential amplifier is described in which the stimulus artifact from recordings of electrically or magnetically evoked biopotentials is minimized by a special active filter. The amplifier is tested in different experiments and the recordings are compared to standard EMG recordings.

Action Potentials↗