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Biomedical subjects

H Voss

Publications and source records attributed to H Voss.

At least 73 records · Page 4Linked to original sources
PubMed1988

Automated Sanger dideoxy sequencing reaction protocol.

The protocol for Sanger dideoxy chain termination reactions in DNA sequencing is tedious and prone to errors due to the repetitive character of the pipetting steps. An industrial robot, with the addition of a few simple parts, was programmed to automate the dideoxy sequencing reactions. The system is set up in a short time for routine operation and it is faster and more reliable than a human operator. It is flexible and allows variations and optimization of the standard procedure. Disposable microtiter plates at a controlled temperature are used. In one reaction cycle (about 50 min) up to 48 templates are processed. Up to 450 bases were resolved in automated DNA sequencing on samples prepared by the robot. The protocol is applicable to fluorescent as well as to radioactive labeling.

Autoanalysis↗
PubMed1988

T7 DNA polymerase in automated dideoxy sequencing.

T7 DNA polymerase with chemically inactivated 3'-5' exo-nuclease activity, as well as unmodified T7 DNA polymerase, were used for sequencing by the dideoxy method in an automated system with fluorescence labelled primer and on-line detection of laser-excited reaction products. An analysis of signal intensity variations in the C track revealed that low C signals were usually preceded by a T in the sequence. This effect was modified by surrounding nucleotides. Signal intensities were more uniform with T7 polymerase than with the Klenow fragment of DNA polymerase I. Some sequences ambiguous with the Klenow enzyme could easily be evaluated with the T7 enzyme. One sequence could only be read by the unmodified T7 polymerase, while both the Klenow fragment and the chemically modified T7 enzyme gave uninterpretable data.

Base Sequence↗
PubMed1988

Non-radioactive automated sequencing of oligonucleotides by chemical degradation.

A non-radioactive sequencing of fluorescently labelled oligonucleotides by solid-phase chemical degradation is described. Although non-radioactive methods have been reported for the dideoxy chain termination technique, such a method has not yet been developed for the chemical degradation sequencing of DNA fragments. A 21-mer fluorescein labelled M13 sequencing primer was sequenced in an on-line automated system in about 30 minutes. The fluorescent dye and its bond to the oligonucleotide were stable during the chemical reactions used for the base specific degradations. As the sequence is determined on-line during electrophoresis, reloading and running 10 fragments simultaneously allows us to use one gel for sequencing of about 50 different oligonucleotides.

Automation↗
PubMed1988

Two different mRNAs are transcribed from a single genomic locus encoding the chicken erythrocyte anion transport proteins (band 3).

The chicken erythrocyte anion transport protein (band 3 of the erythrocyte cytoskeleton) is a central component taking part in two widely divergent functions of erythroid cells; it is a primary determinant of cytoskeletal architecture and responsible for electroneutral Cl-/HCO3- exchange across the plasma membrane. To analyze interesting aspects of the developmental regulation of this gene, we have cloned the cDNA and genomic counterparts of the erythroid-specific anion transport protein. We show that a single genetic locus for band 3 encodes two different erythroid cell-specific mRNAs, with different translational initiation sites, which predict polypeptides of sizes very close to those observed in vivo. In vitro translation and immune precipitation of synthetic mRNA derived from one putative fully encoding cDNA clone demonstrate that this clone gives rise to a protein which is identical in size and antigenicity to bona fide chicken erythroid band 3.

Amino Acid Sequence↗
PubMed1988

[Noninvasive detection of a coronary arteriovenous fistula by two-dimensional color Doppler echocardiography].

The diagnosis of a left circumflex coronary artery--coronary sinus fistula draining into the right atrium was confirmed by echocardiographic analysis. Two-dimensional echocardiography revealed a dilatation of the left main coronary artery, the left circumflex artery, the coronary sinus and a fistulous communication. Pulsed Doppler echocardiographic study showed a turbulent, continuous flow within the dilated coronary artery, in the coronary sinus and at the site of its drainage into the right atrium. There was a diastolic flow-reversal in the descending aorta in absence of aortic insufficiency. Color Doppler echocardiography enhanced the finding of the correct diagnosis by simultaneously displaying blood flow within various parts of the heart and the coronary vessels. This technique aided in establishing the exact location of the fistula by demonstrating a turbulent blood flow, even in narrow cardiac structures. The echocardiographic diagnosis was confirmed by coronary angiography.

Aged↗
PubMed1988

[Heart catheter dislocation following ventriculo-atrial cerebrospinal fluid drainage. Report of 2 cases].

Implantation of ventriculo-atrial shunt systems for treatment of hydrocephalus internus is a common and useful method. Two cases of cardiac catheter dislocation after adjustment or removal of central venous catheters introduced through the left subclavian vein are reported. Technical and pathophysiological predisposing factors are discussed. Ventriculo-peritoneal drainage is also mentioned as a possibility for avoiding cardiac catheter dislocation. After removal of a central venous catheter in cases of ventriculo-atrial shunts a p.a. X-ray of the chest should be performed.

Adult↗
PubMed1987

A simple and rapid preparation of M13 sequencing templates for manual and automated dideoxy sequencing.

A simple and rapid procedure for the preparation of M13 single stranded DNA sequencing templates which does not involve phenol extractions and alcohol precipitations is described. Bacteriophages are precipitated from media supernatants with acetic acid and recovered on glass fiber filters. Subsequent dissociation of the phages and removal of contaminants is performed while the DNA is bound to the glass. Finally, the purified DNA is eluted in a small volume of low-salt buffer. The yield is higher than that obtained by standard methods. The simplified procedure takes less than 30 minutes and does not demand special skills or equipment; the sequence resolution is as good as that obtained by standard procedures both with the Klenow fragment and T7 DNA polymerase, with radioactive labelling as well as in automated sequencing with a fluorescent label.

Autoanalysis↗
PubMed1985

[Special behavior of the cloacal glands in Proteus anguineus].

In all hitherto examined Urodeles, the cloacal glands are flowing into the cloaca jointly with the hedonic glands, only with the exception of Proteus anguineus, where the cloacal glands are open to the cloaca but the hedonic glands are falling via cutaneous pores on both sides of the cloacal slit.

Animals↗
PubMed1985

[Surface forces as the causative mechanism of epithelial tissue].

It is shown that surface forces are responsible for the shift of cells without order from the interior of a cell accumulation to the periphery surface to erect epithelia or epithalium-like cell aggregations. As a model, the boundary of a blood film is figured showing the epithelium-like ordered erythrocytes of the outermost layer.

Animals↗
PubMed1983

[Long-term course of primary vascular pulmonary hypertension with and without intake of appetite depressants].

1. The long-term follow-up of 22 patients with anorectic drug intake (aminorex fumarate) (AS) and PVPH is compared to 38 patients with PVPH of unknown etiology. 2. The 10-year cumulative survival rate is significantly higher for the AF-positive group (54 +/- 11%) than for the AF-negative patients (15 +/- 6%). 3. In terms of the hemodynamic parameters at the time of diagnosis, there were no differences between the two patient groups. 4. Hemodynamic serial controls in the AF-positive group often show a decrease in pulmonary pressure at rest, in contrast to the AF-negative group. However, in all but one of the patients with a pressure drop at rest there is a considerable increase in pulmonary pressure during exercise. 5. In neither group any correlation is to be found between pulmonary pressure and survival time.

Adolescent↗
PubMed1982

Dyskinetic cerebral palsy. I. Clinical categories, associated neurological abnormalities and incidences.

An unselected series of 116 dyskinetic cerebral palsy cases born 1959-70 was delineated and subgrouped according to neurological criteria into 35 hyperkinetic (30%) and 81 dystonic (70%) cases. Of the hyperkinetics, 80% had a mild motor disability, while 90% of the dystonics had moderate or severe disability. Subordinated spastic signs were found in 9% of the hyperkinetic and in 44% of the dystonic cases. IQ was greater than 90 in 69% of the hyperkinetics and 25% of the dystonics and less than 50 in 11% and 41%, respectively. Two or more additional neurological abnormalities (spasticity, mental retardation, epilepsy, anarthria, dysarthria, hearing deficit) were detected in 46% hyperkinetic and 81% dystonic cases. A heavy multihandicap complex was present predominantly in the dystonic subgroup. The 5-19 year mortality rate was 6% and was confined to the most severely handicapped dystonic cases. The twin rate was 5%. A total of 9% had birth weights less than or equal to 1500 g, and 31% had less than or equal to 2500 g. The weight- and age-specific incidences increased rapidly with decreasing birth weights and gestational ages. The crude incidence of hyperkinetic cerebral palsy was 0.07 and dystonic cerebral palsy 0.17 per thousand live births.

Adolescent↗
PubMed1982

[Traumatic tricuspid insufficiency a clinical study (author's transl)].

Four cases of surgically confirmed traumatic tricuspid insufficiency are presented. There is a characteristic long interval between blunt trauma and onset of cardiac symptoms. Common clinical, radiographic and echocardiographic features of tricuspid insufficiency are described. Cardiac catheterisation and right ventricular angiography confirm the diagnosis and the surgical aspect verifies the traumatic etiology. The indication for surgical treatment by valve replacement is discussed. The results of surgery have been good.

Adolescent↗
PubMed1981

[Experience with special-type pacemaker leads (author's transl)].

The dislodgement rate of endocardially placed pacemaker leads can be decreased by the use of special-type electrodes. Since 1963 a total of 2100 pacemaker implantations was performed. Since 1970 we have been using special-type electrodes in 15 to 20% of our patients each year. The complication rate of all pacemaker leads implanted in the period 1974 to 1978 was 7.6%, the rate of the special type electrodes alone came up to 15%. The lead IE--65--I had the greatest deal of this - 11 out of 43 leads had to be removed. 152 electrodes type IVE--85--armed with metal hooks - were implanted, 18 of which had to be revised and 17 of 117 rigid leads type IE--60--KS--10 revealed failure which made revision necessary. In contrast, 54 screw-in leads type 6957, Medtronik and AE--60--YR, Biotronik caused only one perforation - a lethal one. Primary experiences with a porous tip lead (CPII--4116) are good enough to recommend the use of this electrode as a lead of first choice. We saw 2 dislodgements in 50 implantations. Failure to sense or to pace were never seen (time of observation 2 to 18 months).

Arrhythmias, Cardiac↗