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Biomedical subjects

W Braun

Publications and source records attributed to W Braun.

At least 109 records · Page 6Linked to original sources
PubMed1990

Diagnosis, therapy, and outcome of ventricular septal defects in the 1st year of life: a two-dimensional colour-Doppler echocardiography study.

Between January 1987 and July 1989 a ventricular septal defect (VSD) as a single cardiac lesion was detected in 269 small infants aged less than 1 year. The diagnosis was achieved by two-dimensional echocardiography and Doppler colour flow mapping using subcostal, parasternal, apical, and suprasternal views. VSDs were divided into perimembraneous, muscular, malalignment, and subpulmonary defects. Septal defects in complex lesions and atrioventricular defects were excluded. In group 1 (174 infants up to 4 weeks of age, mean 10 days) 125 muscular (71.8%), 35 (20.1%) perimembraneous, 12 (6.9%) malalignment, and 2 (1.1%) subpulmonary defects were diagnosed. One baby had a combined perimembraneous and muscular defect. In another baby a malalignment defect was associated with an av-canal. In group 2 (95 infants aged 4 weeks to 1 year, mean 4.0 months), 57 (60%) muscular, 32 (33.6%) perimembraneous and 6 (6.3%) malalignment defects were found. Within the maximum observation period of 13 months, spontaneous closure occurred in 72 (42.6%) of 169 infants who had a sufficient follow up. Sixty-four had a muscular (88.9%) and 8 (11.1%) a perimembraneous defect. Surgical intervention was required in 11 patients: five perimembraneous defects were closed, one was palliated. Five infants with a malalignment defect were palliated. The malalignment defect frequently needed surgical intervention even in newborns; it never closed spontaneously. About 10% of patients with perimembraneous septal defect required surgery. Spontaneous closure rarely occurred in early infancy. Muscular VSDs were most frequent but virtually never required therapy. Spontaneous closure rate was about 50% during the 1st year of life.

Echocardiography, Doppler↗
PubMed1990

[Neonatal sepsis: bases and possibilities for immunotherapy and immunoprophylaxis. 2: Immunotherapy].

The physiological immunodeficiency of preterm and term newborns is the major cause of their increased susceptibility to infections. Although nonspecific and specific host defence mechanisms are morphologically intact, there are functional and quantitative defects. Supportive immunotherapy is required to equalize these immunological defects. This article reviews topical possibilities for immunotherapy of neonatal sepsis (exchange transfusion, transfusion of fresh blood or fresh plasma, granulocyte transfusion, use of immunoglobulins, fibronectin, interferon and colony-stimulating factor).

Bacterial Infections↗
PubMed1990

[Neonatal sepsis: bases and possibilities for immunotherapy and immunoprophylaxis. 3: Immunoprophylaxis].

This paper reviews several specific and nonspecific procedures for immunoprophylaxis to prevent bacteriological infections in preterm and term newborns. An active or passive immunization is limited necessarily by the wide range of organisms causing neonatal infections. There exist first experiences regarding the prophylactic use of intravenous gammaglobulins for high-risk neonates or pregnant women with symptoms of infection and at risk for preterm delivery. Bacterial polysaccharide vaccines are under development, but up to now far off any universal availability.

Bacterial Infections↗
PubMed1990

The effect of antibiotics on the function of the phagocytic system.

The present paper reviews the effect of various antibiotics (ATB) on the cells of the phagocytic system. The first part deals with an indirect mechanism of action of ATB, i.e. with changes induced in the bacterial cell which in turn renders these bacteria susceptible to phagocytosis. In the second part, the direct effect of ATB on phagocytic cells is discussed: binding of ATB to phagocytes, penetration into the cell, change in chemotactic (migratory) activity, effects on ingestion of particles, intracellular killing of bacteria and on phagocytosis-associated metabolic changes (e.g. chemiluminescence).

Anti-Bacterial Agents↗
PubMed1990

[The significance of various hematological parameters for the early diagnosis of bacterial infection in premature and full-term neonates. 1. Patients and study methods, normal values for the blood picture of newborn infants].

We examined the white blood count in 101 premature infants and full-term neonates on their first day of life (before or within the 12th hour), on 2nd, 3rd, 4th, 5th, 10th, 15th and 20th day of life. Infection was suspected in the course in 31 infants (without demonstration of pathogenic organisms). In 73 infants without infections we were therefore able to establish normal values. We could establish reference limits corresponding to the standard deviation for all kinds of white blood cells, except the whole leucocyte count. Because of considerable individual differences of the whole white blood cell count in newborns without infections we fixed for this reference limits from 5 to 20 Gpt/l. The means of leucocyte and neutrophil counts reached their maximum in the 12th hour after birth, decreased until the 5th day of life and leveled off then. The segmented neutrophils and the lymphocyte counts crossed over after the 5th day of life resulting in a relative lymphocytosis. The physiologic left shift decreased in the first days of life. These described changes after birth were significant.

Bacterial Infections↗
PubMed1990

[The significance of various hematological parameters for the early diagnosis of bacterial infections in premature and full-term neonates. 2. The blood picture in premature and full-term neonates with suspicion of existing infection or with confirmed infection].

We compared the normal values of white blood counts in premature infants and full-term neonates, as described in part one of this paper, with blood counts of 31 infants with suspected infections and 81 infants with sepsis and/or meningitis. The half of these infected infants had leucocyte and neutrophil counts beyond the reference limits. The values tended to leucopenia in diseases beginning within the first five days of life and to leucocytosis later on. More than 80% of the patients had a left shift. One is able to predict a sepsis with a probability of 16.3%, according to our experiences, with leucocyte counts below 5 or above 20 Gpt/l. In the case of left shift the probability is about 25%. Combining these parameters the predictive value is even mounting to 56.1%. We were able to make a prognosis too referring to the blood count of infants with sepsis.

Bacterial Infections↗
PubMed1990

[The significance of various hematological parameters for the early diagnosis of bacterial infections in premature and full-term neonates. 3. Discussion of the study results].

Haematological examinations may contribute, especially by repeated investigations of parameters changing dynamically, to a greater safety of decisions concerning the beginning or termination of chemotherapy in neonates with suspected infections. We recommend to check the blood count every 6-12 h in such cases. A normal blood count does not exclude a sepsis but haematological changes may precede clinical symptoms for hours. We can confirm the good experiences of some authors with "screening-scores" to detect early infants with sepsis. Such a score should include I/T-Quotient, thrombocyte count, CRP and micro-ESR. This contributes to a greater predictive probability of an infection.

Bacterial Infections↗
PubMed1990

Vinpocetine therapy does not change imipramine pharmacokinetics in man.

The influence of vinpocetine on imipramine steady-state plasma levels was investigated in 18 healthy volunteers. Twenty-five mg imipramine were given t.i.d. for a total of 21 days, vinpocetine treatment was started on day 11 with 10 mg t.i.d. and continued until the end of the study. The AUC of imipramine plasma levels were obtained using consecutive imipramine plasma level determinations from samples drawn every 2 h from 8:00 a.m. to 8:00 p.m. by trapezoidal rule. AUCs of day 10 without and of day 21 during concomitant vinpocetine treatment were compared, demonstrating the independence of imipramine's bioavailability from concomitant vinpocetine treatment. There were no indications to assume a changed absorption of imipramine due to vinpocetine as would be reflected in Cmax and tmax values. Imipramine metabolization to the still effective metabolite desipramine shows a huge interindividual variability although it remains constant for the individual. The analysis of this parameter in the course of this study does not suggest that it is changed due to vinpocetine treatment.

Adult↗
PubMed1990

[Development and organization of breast milk collection centers in East Germany].

Human milk banking has a longstanding tradition in the GDR. We report on the main data of a survey carried out in 1987, actualized in 1989. Whereas human milk banking was widespread during the 1950s, it reached it's lowest level in 1972. In 1988 the amount of collected milk was nearly 200,000 litres (60 milk banks). Thus, the supply met the demand approximately. The development of the human milk banks is characterized by an increase of the number of milk banks (mostly the banks are affiliated to a children's hospital) and the collecting capacity. Half of the milk banks carries out the collection on a daily basis. This makes it possible to provide fresh milk with it's clear-cut advantages, especially in immunological respect. Otherwise the milk is stored after boiling, freezing or pasteurization. The feeding of very low birth weight newborns with fresh human milk is steadily increasing with corresponding consequences for the quality control of donated milk and the management of milk banks.

Germany, East↗
PubMed1990

[Indications for the conservative treatment of patella fractures].

It is uncontested that most patellar fractures have to be treated by open reduction and internal fixation. Nevertheless, there are well-defined types of patellar fractures in which such a procedure is unnecessary, either because the fracture is stable or because the retropatellar surface is intact. In these fractures internal fixation would constitute overtreatment; conservative treatment yields good results in such cases.

Adult↗
PubMed1989

Solution conformation of conotoxin GI determined by 1H nuclear magnetic resonance spectroscopy and distance geometry calculations.

Conformational analysis of conotoxin GI, one of the neurotoxic peptides produced by a marine snail, genus Conus, was performed by a combination of nuclear magnetic resonance spectroscopy (NMR) and distance geometry calculations. The resulting conformers on minimization of the target function were classified into two groups. The difference in the structures of the conformers is mainly due to the difference in the orientation of the side chain of the tyrosyl residue. The results show that the solution structure of conotoxin GI satisfies the conformational requirements for the biological activity of an antagonist toward nicotinic cholinergic receptors elucidated in a series of studies on alkaloids. The structure is discussed on the basis of the results of comparison of the atomic arrangements of the active sites of snake venom peptides and molecular models based on the results of secondary structure prediction.

Amino Acid Sequence↗
PubMed1989

Stimulation of bile acid active transport related to increased mucosal cyclic AMP content in rat ileum in vitro.

The regulation of bile acid transport in rat ileum was studied in vitro using the adenylate cyclase stimulator forskolin, or 3-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase inhibitor. Forskolin 20 microM as well as 100 microM IBMX enhanced mucosal cyclic AMP to 3-fold the control levels. As a physiological response, net fluid absorption in everted ileal sacs was reduced. Taurocholate (10-500 microM) transfer in everted perfused segments of rat ileum was measured using a three compartment dual label method suitable for measuring active transport. Transport asymmetry with absorption exceeding its counterflux by 26-fold, was measured at 500 microM taurocholate. Forskolin increased absorption of taurocholate still further, by 68%, and reduced the serosal to mucosal flux. Enhanced intracellular accumulation of taurocholate indicated a stimulatory action of forskolin on active transport at the mucosal brush-border membrane. In uptake studies, accumulation of taurocholate was enhanced by 100 microM IBMX also. Forskolin-induced uptake stimulation could also be shown for chenodeoxycholate and cholate. In the presence of the neuronal blocker tetrodotoxin, uptake stimulation was still effective. Results indicate that the ileal bile acid transporter is included within the group of sodium-dependent cotransporters of the rat small intestine which are subject to a cyclic AMP-related stimulation at the mucosal cellular level.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Solution of the phase problem in the X-ray diffraction method for proteins with the nuclear magnetic resonance solution structure as initial model. Patterson search and refinement for the alpha-amylase inhibitor tendamistat.

Patterson search calculations using the three-dimensional structure of the alpha-amylase inhibitor from Streptomyces tendae obtained from experimental nuclear magnetic resonance (n.m.r.) data were performed to study the possibility of solving the phase problem in the X-ray diffraction method with protein structures determined by n.m.r. Using all heavy atoms (C, N, O, S) of the residues 5 to 73 in the best n.m.r. structure of the alpha-amylase inhibitor (520 out of the 558 heavy atoms in the complete polypeptide chain), the maximum of the rotation function corresponded to the correct solution obtained by the previous independent determination of the crystal structure. However, additional local maxima, which are not significantly lower than the global maximum, also showed up. Performing the Patterson search with a model containing the backbone atoms and the heavy atoms of only the interior side-chains (399 atoms), which are much better defined by the n.m.r. data, the correct maximum was significantly higher than all other maxima. A translation search for the best orientation of the latter model yielded the correct solution. The energy-restrained crystallographic refinement was performed with this model to an R-factor of 26%. This corresponds approximately to the R-factor calculated for the X-ray crystal structure previously determined using the isomorphous replacement technique, if the residues 1 to 4 and 74 and all localized solvent molecules were removed from this structure. During the refinement the root-mean-square deviation between the two structures decreased from 1.03 A to 0.26 A for the polypeptide backbone and from 1.64 A to 0.73 A for all heavy atoms. There are no major local conformational differences between the two structures, with the single exception of the side-chain of Gln52.

Bacterial Proteins↗
PubMed1989

Comparison of the high-resolution structures of the alpha-amylase inhibitor tendamistat determined by nuclear magnetic resonance in solution and by X-ray diffraction in single crystals.

The three-dimensional structure of the alpha-amylase inhibitor Tendamistat determined by nuclear magnetic resonance in aqueous solution is compared with the Tendamistat crystal structure refined at 2.0 A resolution. Between the two independently obtained structures the root-mean-square distances are 1.05 A for the backbone atoms N, C alpha and C', 1.25 A for the backbone and the interior side-chains, and 1.84 A for all heavy atoms. These numbers show that the interior of the molecule is nearly identical in the two states. Near the protein surface a small number of local differences between the two structures were identified. In most surface areas the solution structure appears more disordered than the crystal structure, with the exception of Tyr15, which was not observed in the X-ray diffraction.

Magnetic Resonance Spectroscopy↗
PubMed1989

Modified diffusion blotting for rapid and efficient protein transfer with PhastSystem.

An easy-to-perform and efficient blotting method was developed for the transfer of proteins separated in PhastGel media. The method was evaluated by comparing the blotting results of low molecular weight marker proteins at different times. 14C-Labelled proteins were used for the assessment of the transfer efficiency. Highly efficient transfer was achieved within 1 h of blotting and the proteins were almost completely eluted from the gel in 2 h. The gel remained on its solid plastic backing, which is not the case when using an electrophoretic transfer method. As little as 1.25 ng of electrophoretically separated protein were enzymatically detected on the blot when applying blot-biotinylation. The transfer was performed at low temperature (4 degrees C), which-in contrast to thermoblotting-additionally offers the chance to blot thermolabile proteins. These superior features, together with the method's versatility and low cost, mark an interesting alternative to the previously recommended blotting procedures after PhastSystem electrophoresis.

Blotting, Western↗