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Biomedical subjects

A Hoffmann

Publications and source records attributed to A Hoffmann.

At least 271 records · Page 15Linked to original sources
PubMed1992

Influence of different pressure gradients on late clinical outcome after aortic valve replacement.

Late outcome vs. hemodynamic parameters were assessed and compared in a series of 44 patients followed for 10-17 years after aortic valve replacement either with a Starr-Edwards A 1260 (SE) or a Bjork-Shiley 60 degrees (BS) prosthesis. The two groups, 22 patients each, were selected by computer from the data base SG as to be matched for age, sex, underlying lesion, date of implantation, valve size, left ventricular function, and concomitant coronary artery disease. There was no significant difference in mortality and complication rates. Clinical evaluation at a mean of 12.5 +/- 2.2 years postoperatively revealed identical findings of heart size on chest X-rays (CTR 0.50 +/- 0.04 SE vs. 0.50 +/- 0.05 BS) and nearly identical incidence of left ventricular hypertrophy on the ECG (2/22 SE and 1/22 BS). There was a statistically significant difference in Doppler ultrasonic peak pressure gradients between the two valve types (SE 32 +/- 15 mmHg, BS 23 +/- 9 mmHg; p = 0.047), and of fractional shortening on M-mode echocardiograms (SE 30 +/- 9%, BS 37 +/- 8%, p = 0.038), but this was not reflected by a difference in the symptomatic status of the two groups. It is concluded, that in two groups of patients surviving 10-17 years after isolated aortic valve replacement with SE or BS valves, the statistically significant nine mmHg difference in gradient across the two valve types had no effect on long-term clinical outcome.

Aortic Valve↗
PubMed1992

Drug use in pregnancy: east German data of an international collaborative study.

In an epidemiological collaborative international study under the auspices of WHO-Euro the drug use in pregnancy was investigated in 22 countries in 14,778 women and in hospitals of three different levels. The East German state Thuringia took part according to the annual birth rate with 300 women in 3 hospitals (Jena, Gera, Greiz). In the international average, 14% of the enrolled women took no drugs during pregnancy before admission to hospital for delivery. In East Germany 44% of the women taking part in the study had no drug administration during pregnancy. The critical use of iron preparations and vitamins there has to be mentioned. Under delivery, 99% of the Thuringian women received drugs. In the puerperium the administration of ergot derivatives and of laxatives exceeds the international average and has to be critically revised, but the administration of antiinfectives in only 1/5 and of analgetics 1/3 of the international average.

Drug Utilization↗
PubMed1992

Investigations into a new antiarrhythmic substance Z-2-amino-5-chlor-benzophenon-amidin-hydralazin in humans.

Z-2-amino-5-chlor-benzophenon-amidin-hydralazin is a new chemical potential antiarrhythmic substance. The blood levels were investigated after different dosages and forms of administration in patients and volunteers. The determination of the substance can be performed by high-pressure liquid chromatography. In addition the pharmacokinetic parameters were calculated. The pharmacokinetic profile is similar in humans and animals.

Administration, Oral↗
PubMed1992

[Drug prevention and therapy of ventricular tachycardia].

Antiarrhythmic drugs of type I to IV (Vaughan Williams) are generally used for the treatment of ventricular tachycardia, especially in patients with symptomatic and hemodynamically not tolerated arrhythmias; however, randomized controlled studies revealed a beneficial effect on sudden cardiac death only for type-II (beta-blocking agents) and type-III (Amiodarone) antiarrhythmic drugs. These drugs are, therefore, the antiarrhythmic agents of first choice; but, in addition, underlying heart disease, triggering factors and heart-rate dependency should be considered.

Anti-Arrhythmia Agents↗
PubMed1992

Lack of effect of diacetyl-splenopentin (Berlopentin) on the pharmacokinetics of caffeine.

The influence of Berlopentin on caffeine clearance was measured after a 6 week i.v. treatment or a 4 week s.c. administration within a phase I trial. It was demonstrated that therapy with Berlopentin did not affect significantly caffeine elimination. Thus, clearance of drugs which are biotransformed by hepatic microsomal oxidation are unlikely to be affected by the coadministration of Berlopentin.

Adult↗
PubMed1991

[Hemodynamics of various heart valve prostheses].

Modern tilting disc and bileaflet prostheses, and bio-prostheses, perform similarly regarding pressure gradients, discharge coefficient and performance index; however, only bio-prostheses increase their opening area with increasing flow. Ball valve prostheses of the Starr-Edwards type perform less satisfactorily with higher pressure gradients and lower performance indices, which may result in less favorable long-term follow-up. Bio-prostheses show degenerative changes with increasing age which, over a period of 7-10 years, can lead to clinically relevant stenoses necessitating reoperation.

Bioprosthesis↗
PubMed1991

Structural motifs and potential sigma homologies in the large subunit of human general transcription factor TFIIE.

The general transcription factor TFIIE has an essential role in eukaryotic transcription initiation together with RNA polymerase II and other general factors. Human TFIIE consists of two subunits of relative molecular mass 57,000 (TFIIE-alpha) and 34,000 (TFIIE-beta) and joins the preinitiation complex after RNA polymerase II and TFIIF. Here we report the cloning and structure of a complementary DNA encoding a functional human TFIIE-alpha. TFIIE-alpha is necessary for transcription initiation together with TFIIE-beta, and recombinant TFIIE-alpha can fully replace the natural subunit in an in vitro transcription assay. The sequence contains several interesting structural motifs (leucine repeat, zinc finger and helix-turn-helix) and sequence similarities to bacterial sigma factors that suggest direct involvement in the regulation of transcription initiation.

Amino Acid Sequence↗
PubMed1991

The electrochemical proton potential of Bacillus alcalophilus.

Bacillus alcalophilus strain ATCC 27647 showed usual growth characteristics, when inoculated at pH 10.4. The cells entered the logarithmic phase at pH 10.3, and as growth continued, the pH dropped further to a value of 8.8 in the stationary phase. B. alcalophilus strain DSM 485 showed comparable growth only in the initial phase after the addition to fresh medium. The small initial growth period was succeeded by a long lag phase, where the pH continuously dropped. The cells resumed growth after the pH was about 10.0 and continued to grow accompanied by a further decrease of external pH. The bioenergetic parameters measured in the initial growth phase of the two strains at high pH (10.1-10.3) were nearly the same, i.e. delta pH = +97 to +110 mV, delta psi = -206 to -213 mV and delta microH+ = -109 to -103 mV. The inverted proton gradient of about 1.7-1.9 at high pH decreased, as the external pH dropped during growth. This led to an increase of the proton motive force (delta microH+), although the membrane potential (delta psi) also declined. The ATP/ADP ratio of strain DSM 485 was high (4.5-5.5) at fast growth during the initial and second growth period. The ratio declined to about 1.5 at the end of the lag phase. At the initial growth phase and at the end of the lag phase, the delta microH+ was, however, the same (approximately -106 mV) and considerably lower than in the middle of the second growth period (approximately -140 mV). Fast growth, therefore, correlates with a high ATP/ADP ratio but not necessarily with a high delta microH+. Addition of gramicidin or carbonylcyanide m-chlorophenylhydrazone stopped growth of B. alcalophilus strain DSM 485 at pH 10.3 or 9.5 and gramicidin immediately decreased the internal ATP/ADP ratio from 4.5 to 1.2 at pH 10.3.

Adenosine Diphosphate↗
PubMed1991

Striking homology of the 'variable' N-terminal as well as the 'conserved core' domains of the mouse and human TATA-factors (TFIID).

A complementary DNA (cDNA) encoding a mouse TFIID (mIID) was isolated from mouse brain cDNA libraries. The 316 amino acid sequence deduced from cDNA sequences revealed the presence of an amino-terminal region enriched in serine, threonine, and proline (STP-cluster), an uninterrupted stretch of 13 glutamine residues (Q-run), a second STP-cluster, and a conserved carboxy-terminal region. Amino acid sequences of the first STP-cluster and the conserved carboxy-terminal region were identical to those of the human TFIID (hIID). However, the Q-run was considerably shorter than that in hIID and sequences in the second STP-cluster diverged from those of the hIID. The murine TFIID transcript is expressed as a 2 kilobase poly(A)+ RNA in the mouse brain. Southern blot analysis identified a single gene copy per haploid mouse genome.

Amino Acid Sequence↗