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Biomedical subjects

M Friedrich

Publications and source records attributed to M Friedrich.

At least 253 records · Page 14Linked to original sources
PubMed1985

[Comparative studies on the enzymatic absorption of protein hydrolysates in the small intestines of the rat. 3. The absorption of trypsin, thermitatic and trypsin thermitatic wheat gluten hydrolysates in comparison with equimolar mixtures of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic wheat-gluten hydrolyzates as well as their equimolar amino-acid mixture were perfused through proximal and distal parts of the intestine (10 cm length) of non-narcotized rats. The total amino-acid concentration of the perfused solution was 50 mM. The tryptic hydrolyzate showed a significantly lower absorption of nitrogen and total amino acids than the amino-acid mixture. Both the supplied forms were very different as to their absorption pattern of the amino acids. The high variability of the percental absorption of the individual amino acids of the tryptic hydrolyzate results in a high coefficient of variation. The absorption of nitrogen and total amino acids from thermitatic and tryptic-thermitatic hydrolyzates is equal to that from the amino-acid mixture. In a peptidic form glutamic acid is more rapidly absorbed from the two hydrolyzates, and methionine from the tryptic-thermitatic hydrolyzate in both the intestinal parts. As to alanine and glycine this concerns only the distal intestinal part for both the hydrolyzates. There are no differences between the absorption patterns of the two hydrolyzates but in comparison with the amino-acid mixture and the tryptic hydrolyzate differences were evident. The coefficients of variation of both the hydrolyzates are significantly lower as compared to those of the tryptic hydrolyzate and the amino-acid mixture. All forms of supply are more rapidly absorbed in the distal than in the proximal part of the intestine.

Amino Acids↗
PubMed1985

[Comparative studies on the enzymatic absorption of protein hydrolysates in the small intestine of the rat. 3. The absorption trypsins thermatatic and trypsin-thermatatic hydrolysates of a fava bean protein isolate compared to an equimolar mixture of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic Faba bean protein hydrolyzates as well as their equimolar mixture of amino acids were perfused through proximal and distal parts of the intestine (10 cm length) of non-narcotized rats. The total amino-acid concentration of the perfused solution was 50 mM. The absorption of nitrogen and total amino acids from the tryptic and tryptic-thermitatic hydrolyzates was lower than that from the amino-acid mixture, the absorption from the thermitatic hydrolyzate was in accordance with that from the amino-acid mixture. The absorption pattern of the amino acids which preferably undergo a peptidic absorption is similar with the three hydrolyzates: in the proximal intestinal part this concerns glutamic acid and serine, in the distal intestinal part--methionine, alanine, glycin, and serine. The absorption pattern of the amino acids is different between the three hydrolyzates and the amino-acid mixture. Between the absorption pattern of the amino acids from the three hydrolyzates little differences were evident only in the proximal intestinal part. The coefficients of variation of the tryptic-thermitatic hydrolyzates are in accordance with those of the amino-acid mixture, whereas that of the thermitatic hydrolyzates is significantly lower. In the distal intestinal part all supplied forms are more rapidly absorbed than in the proximal part of the intestine.

Amino Acids↗
PubMed1985

[Comparative study of the absorption of enzymatic protein hydrolysates in the small intestine of the rat. 2. The absorption of tryptic, thermitatic and tryptic-thermitatic casein hydrolysates compared with the equimolar composition of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic casein hydrolyzates as well as their equimolar amino-acid mixture were perfused through proximal and distal parts of the intestine (10 cm length) of nonanaesthesized rats. The total amino-acid concentration of the perfused solution was 50 mM. The absorption of nitrogen and total amino acids respectively did not reveal significant absorption advantages in favour of the hydrolyzates. In contrast to this, some peptidic bound amino acids of these hydrolyzates show a significantly better absorption as compared to free amino acids. At this, dependences of the kind of hydrolyzate and the part of the intestine are evident. Glutamic acid, e.g. is generally more rapidly absorbed when peptidic bound; methionine is more rapidly absorbed only from the thermitatic and tryptic-thermitatic hydrolyzates, and alanine and glycin only in the distal part of the intestine. Independent of the amino acid or peptide substrate the total absorption of all the amino acids is higher in the distal part of the intestine. The comparison concerning the ranking order of the single amino-acid absorption rates shows in the two parts of the intestine distinct differences between the amino-acid mixtures and the enzymatic hydrolyzates. The lowest differences were found between the thermitatic and the tryptic-thermitatic hydrolyzate. Both of them have approximately the same degrees of hydrolysis (30 and 35%, respectively). The variability of the amino-acid absorption from the three casein hydrolyzates is lower in comparison with the amino-acid mixture. The tryptic-thermitatic hydrolyzates have the lowest coefficients of variability.

Amino Acids↗
PubMed1985

[Advances in possibilities for protein evaluation].

With protein evaluation the changing abilities of food proteins are characterized with regard to their covering the requirements of the organism for protein or amino acids, respectively. The biological value of proteins is influenced by several factors. Measuring the reaction of the whole organism (of man or animal) to the food protein the sum of all influencing factors is covered. Hence, these direct evaluation methods have priority. The general dose-reaction curve demonstrates the direct evaluation methods: The evaluation criteria protein efficiency or minimum protein requirement are presented and the different possibilities of interpretion are compared. Most direct evaluation methods are performed with suboptimal protein supply, therefore values for an optimum protein supply can be derived only with reservation. Improved values for protein evaluation can be obtained from investigations of the protein metabolism. With that the substrat-related evaluation can be more orientated to a organism-related one. Indirect biochemical evaluation methods are less important. That does not concern in-vitro evaluation by amino-acid analysis and/or in-vitro digestibility tests. Possibilities and limits of these methods are discussed.

Amino Acids↗
PubMed1985

[Status of penis sonography in andrology].

Good visualization of the anatomic structures of the penis can be achieved by application of high-resolution real-time sonography and a water path. Penis sonography is painless, free of risk and easy to perform. It is ideal for documentation and assessment of pathological alterations of the penis. 80 patients with penile deviation were examined sonographically. In cases of Peyronie's disease, the most frequent clinical picture, it is possible to achieve good localization and measurement of the fibrotic plaques in the area of the tunica albuginea. Calcifications can be clearly detected. In cases of penile deviation associated with the urethral manipulation syndrome, no fibroses are seen in the corpus spongiosum. In 3 patients with erectile impotence after priapism, sonography permitted precise determination of the extent of fibrosis formation in the corpora cavernosa.

Adult↗
PubMed1984

[Complex evaluation of film mammography imaging systems. I. Methodological principles].

Today the range of image-recording systems in film mammography is so wide that an evaluation is only possible taking each and every technical parameter into account. The signal-to-noise ratio as defined in our earlier publications (10, 11) comprises all of these parameters. Trying to define the signal-to-noise ratio, especially the calculation of noise energy remains controversial and problematic. As its equivalent, the so-called noise-equivalent pass band of the human visual system for the different detail sizes is used. The signal-to-noise ratio is depicted as a matrix in an isometric plot. It demonstrates all of the imaging qualities of the recording system within the range covered by the experimental measurements. Different quality definitions of information theory, such as information quality and information capacity, can be deduced from the signal-to-noise matrices, enabling a comparison with digital storage media.

Evaluation Studies as Topic↗
PubMed1984

[Complex evaluation of film mammographic imaging systems. 2. Comparison of 18 systems using a signal-noise matrix].

The concept of the signal-noise matrix with physiological optical noise measurements for defining visibility thresholds provides a quantitative means for comparing film mammographic systems (9). Eighteen such systems were compared. A graded list can be produced relating the integrated signal-noise ratio to area and detail contrast (image quality) and to the required radiation dose (dose efficiency). For this, maximal dose (industrial film) and minimal image quality can be taken into consideration. In this list, in agreement with other publications (12) high resolution film-screen combinations, using industrial film (eg. Cronex 70/screen) come top. In combination with a grid technique, this system achieves a greatly superior image quality. Amongst commercial film-screen systems, only the Trimax mammography system with high resolution screens is comparable. All other commercial systems (single or double coated films) are unsatisfactory with respect to their dose efficiency and image quality. Some industrial films without screens (Mamoray M4) are intermediate between high definition and other commercial systems. Ninety-second, screenless films offered for mammography appear unsuitable for this purpose, both in view of their dose efficiency and image quality.

Evaluation Studies as Topic↗
PubMed1984

[Slit-aperture technic in mammography].

Following a discussion of various principles used in the elimination of scatter, the prototype of a simple slit aperture mammography apparatus is described (modified Mammomat, Siemens). The main advantage of this technique compared with grid mammography is a halving of the radiation dose for identical image quality, using an identical film system. The technical requirements (heavy duty tube, new generator) are, however, considerable. If the film-screen systems currently in use are to remain the common systems for the future, then the development of a multi-lamellar slit diaphragm technique carries much promise for mammography.

Mammography↗
PubMed1984

[Absorption of enzymatic protein hydrolysates and equimolar amino acid mixtures in the perfused small intestine of the rat].

Casein, wheat gluten or field-bean protein isolate (vicia faba) was hydrolyzed enzymatically by trypsin or thermitase (proteinase from Thermoactinomyces vulgaris). The degree of splitting of the protein peptide bounds was, resp., 18% or 30% for casein, 8% or 30% for wheat gluten and 16% or 29% for the field-bean protein isolate. The peptide pattern of the protein hydrolysates was measured by gel chromatography. The absorption of the enzymatic protein hydrolysates was compared with the absorption of the equimolar mixtures of free amino acids by perfusion of the distal or proximal part of the small intestine of nonanaesthesized rats. The absorption was measured on the basis of the amino acid disappearance from the perfused part of the small intestine and expressed as absorption of the total amino acids, of each single amino acid and as coefficient of variation of amino acid absorption. There are no differences in the total amino acid absorption of the tryptic casein hydrolysate and the three thermitatic protein hydrolysates compared with their corresponding mixtures of free amino acids. The absorption is decreased in case of larger oligopeptides. Their preceding mucosal hydrolysis is slower than the absorption of the splitting products. This is true for tryptic hydrolysates of wheat gluten and field-bean protein. The absorption patterns of the single amino acids are different for protein hydrolysates compared with their equimolar mixtures of amino acids in case of a same total absorption, too. The coefficient of variation is low (more equal amino acid absorption) in hydrolysates consisting of a homogeneous mixture of low molecular weight peptides. It is more increased in mixtures of free amino acids or in hydrolysates containing longer-chain peptides.

Animals↗