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R Dölp

Publications and source records attributed to R Dölp.

At least 19 recordsLinked to original sources
PubMed1995

[Psychometric function of stereo disparity in normal persons].

UNLABELLED: The accuracy and efficiency of threshold estimation depend on a priori knowledge of the shape of the psychometric function. Such knowledge is available for contrast detection and visual acuity, but not for disparity detection. METHODS: We studied the psychometric function for disparity detection in 26 visually normal, untrained observers by measuring detection rates over a wide range of disparities. In a two-alternative forced-choice (2AFC) task the subject had to decide whether the right or left of two vertical bars, differing in depth, was closer to them. An S-shaped Weibull function was fitted to each subjects's data using the maximum-likelihood procedure. RESULTS: In 21 of the 26 subjects the psychometric function rose with increasing disparities up to a level of about 100%. Five of the 26 subjects only reached hit rates clearly below 100% (66% to 82%), even at disparities well above the threshold. The mean slpe of the S-shaped psychometric function of disparity detection was much lower (1.2 Weibull units) than that known for visual acuity and contrast detection (about 3.0 Weibull units). The slope differed widely among subjects, but was not related to stereo acuity. CONCLUSION: For accurate and efficient estimation of stereo acuity, the shallow slope of the psychometric function requires more than 100 single trials around the threshold if a 2AFC procedure is used. In addition, several disparities well above the threshold must be presented in order to detect subjects who do not reach a hit rate of 100% at any disparity. Otherwise, stereo acuity would be underestimated in these subjects.

Adult↗
PubMed1987

[Clinical studies of peripheral venous parenteral nutrition. Effect of a 3.5% amino acid solution on postoperative metabolism with special reference to amino acid homeostasis].

We studied 20 patients following vaginal hysterectomy until the third postoperative day. 10 patients (group I) in this randomized controlled study were infused only with water and electrolytes in a volume of 40 ml/kg BW. 10 patients (group II) received a 3.5% amino-acid solution with 6% carbohydrates in the same volume. In group II the nitrogen balance was significantly better than in group I. The nitrogen retention of 81% was judged as rather good. We have shown that there were no changes in the concentration of free plasma amino acids in group II, opposite we found significant changes especially in the branched-chain amino acids and alanine in group I. The normalization of metabolized amino acids and the normal concentration of the nonesterified fatty acids in group II demonstrated that the utilization of added amino acids took place not only in peripheral but also in visceral tissues. Our study indicates that the proven amino-acid solution can be recommended as peripheral-venous parenteral nutrition in the postoperative phase.

Amino Acids↗
PubMed1987

[Anesthesiologic viewpoints of endonasal paranasal sinus surgery].

There must be close cooperation between the surgeon and the anaesthetist during surgery of the paranasal sinuses. The surgeon needs a bloodless field which the anaesthetist can achieve by lowering the patient's arterial blood pressure using controlled hypotension. Controlled hypotension carries considerable risks, and only selected cases should be treated with this method. There are two hypotensive drugs of choice: sodium nitroprusside and nitroglycerin. If the circulation and ventilation are monitored sufficiently, the surgeon can expect good results with diminished blood loss.

Anesthesia, General↗
PubMed1984

[Parenteral administration of amino acids. Reference values--study technic--interpretation of the study results--amino acid pattern as a criterion of the regulation of homeostasis].

The concentrations of free amino acids were measured in lithium-heparinat-plasma with a standardized quality controlled analytical procedure in 200 healthy persons (blood donors). The distribution of the measured values were statistically evaluated in the total group and differentiated in the male and female subcollective. The absolute total concentrations of the free amino acids vary in a broad range between 1.7 and 4.4 mmol/l. This large range is also seen for the single amino acid. In a new system for documentation and interpretation of analytical data the measured values are collected and mean, median, standard deviation, mini-max-range and 95% confidence interval are automatically computed. On this basis of data a physiological reference range is defined. The broad variability of the absolute concentrations is not found in the relative composition of the pattern. The relations of the amino acid concentrations which are important for the quality of the cellular support are very constant. Their importance is caused by the fact that only few different transport systems exist for at least 20 amino acids, which means that the different amino acids are competing at the same system for cellular uptake. The essential of the results in this study is that the liver guarantees the constancy of the physiological pattern also in cases where the exogenous supply differs from the characteristics of elimination of the single amino acid from blood. Only when the oxidative capacity of the liver is insufficient as in pathological states like infections pathological concentrations are found. In these cases the true change is undiscovered when the absolute concentrations are considered, because the insufficient functions of the liver causes initially high total concentrations. For the interpretation of an analysis of amino acids in blood plasma two main criteria are necessary: the total concentration of amino acid characterizes the quantitative support while the concentration pattern determines the quality of the cellular uptake.

Adult↗
PubMed1984

[Parenteral administration of amino acids to septic patients].

The study investigates the status of plasma amino acids and their pathological changes under the specific conditions of sepsis in 20 intensive care patients, who were randomized into two groups with and without amino acid support. The study was designed to determine whether the concentration of the free amino acids in plasma or their relative proportions to each other determine the cellular uptake under septic conditions in such a way that would have relevance for the exogenous supply. Sepsis was defined as an increase in body temperature above 38 degrees C, a positive blood culture and changes in the white blood cell picture. Carefully standardized and quality-controlled low-pressure liquid chromatography was used along with a new procedure for data processing, based on personal physiological range with known ranges for individual amino acids. The concentrations of individual amino acids vary widely and did not allow a decision to be made about disturbance of homeostasis. The mean total concentrations varied between 1.27 mmol/l and 4.40 mmol/l. The range was similar whether amino acids were administered or not. This variation was also found in the branched chain amino acids, which were considered to have a specific importance in septic states. Valine varied between 114 mumol/l. The relative proportion of the individual amino acids to the whole amount of amino acids showed less variation and demonstrates that the oxidative action of the liver is able to correct any deviation from the normal and maintains the uptake of amino acids by the cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1983

[Enteral or parenteral feeding therapy. Comparative clinical study].

We investigated 20 patients - randomized into two groups - in a period of six postoperative days. We wanted to prove, whether parenteral and enteral feeding show differences in their nutritional effect. Both, parenteral and enteral nutrition had the same content of calories and nitrogen. The application of parenteral nutrition proceeded via central venous catheter and of enteral nutrition via tube feeding into the first part of the jejunum. There were no differences to be shown between both groups. Changes of the investigated datas from day to day had been typical changes within the postaggression syndrome. It was proven that tube feeding could be started in the early postoperative period. The tube diet was well tolerated and totally absorbed in the intestine. We believe that this form of tube feeding with a special diet may be a definite alternative to parenteral nutrition in patients within intensive care units and after surgery also in the very early postoperative period.

Adult↗
PubMed1982

The effect of solutions of varying branched-chain concentration on the plasma amino acid pattern and metabolism in intensive care patients.

30 intensive care surgical patients were investigated over a period of five days following trauma or major surgery. They were randomised by card into two groups, Group I received an amino acid solution containing 45 per cent branched-chain amino acids (BCAA), and group II an amino acid solution with a 10 per cent content of BCAAs. After 24 hours of infusion, the total amino acid concentration and branched-chain amino acid concentration in the plasma of Group I patients already clearly exceeded the normal range, and continued to increase during the period of study. In Group II these parameters rapidly returned to normal where they remained. Cumulative negative nitrogen balance and nitrogen excretion on each day of investigation were significantly less in Group II. These results indicate that after severe trauma or major surgery amino acid solutions containing high concentrations of BCAAs may be an unphysiological load on the already stressed metabolism, rather than a benefit.

Journal Article↗
PubMed1982

[Effect of solutions with different amounts of branched-chain amino acids on the plasma amino acid pattern and energy metabolism of surgical intensive care patients].

30 intensive care surgical patients were investigated over a period of five days following trauma or major surgery. The patients were randomized into two groups. Both collectives received equal amounts of protein (1.0 g amino acids . kg-1 . d-1) and carbohydrate (6,7 g . kg-1 . d-1). Under this infusion regimen the patients of group I received an amino acid solution containing 45% branched-chain amino acids (BCCA), the patients of group II an amino acid solution with a 10% content of BCAAs. After only 24 hrs of infusion, the total amino acid concentration and branched-chain amino acid concentration in the plasma of patients receiving the solutions containing 45% BCAAs already clearly exceeded reference range, and continued increase during the entire investigation period. In those patients receiving the 10% branched-chain amino acid solution, these parameters rapidly returned to normal and then remained within reference range. Cumulative nitrogen balance and nitrogen balance on each day of investigation were significantly less negative in those patients administered the amino acid solution with small amounts of BCAAs. These results seem to indicate that after severe trauma or major surgery amino acid solutions containing high concentrations of BCAAs may be an unphysiological load on the already stressed metabolism, rather than a benefit

Adult↗
PubMed1981

[Enteral feeding. New technics and feeding mixtures].

We tried to show, that feeding via intrajejunal tube with a chemically defined diet (CDD) is a procedure possible done in the early postoperative situation beginning with the 1st postoperative day. We investigated 20 patients after cholecystectomy - randomized into two groups (group I: CDD, group II: control; water - electrolyte - substitution via peripheral veins). It was proven, that the CDD - group tolerated the enteral feeding from the beginning very well. The N balance became positive on the 2nd postoperative day. Further investigations and results have to show if this form of tube feeding with a special diet may be a definite alternative to parenteral nutrition in patients after gastrointestinal surgery in the very early postoperative period.

Adult↗
PubMed1981

[Behavior of free amino acids in plasma and urine of intensive care patients with multiple injuries during the administration of an amino acid solution with 10% branched-chain amino acids].

The study was performed on eleven severely injured ventilated intensive care patients. Plasma and urine concentrations of free amino acids, nitrogen balance and energy expenditure were studied for a period of six days following trauma. Most of the free amino acids in plasma, especially the BCAA's return to reference range within a few days after trauma on administering the infusion solution investigated. An amino acid imbalance in the plasma of severely traumatized patients could be avoided by infusion of an amino acid solution containing only 10% branched-chain amino acids. The amino acids infused are utilized to an extent of more than 90%. However, a still markedly increased negative nitrogen balance, as well as a clearly negative energy balance indicate, that further investigations on nitrogen - and carbohydrate supply are necessary.

Adolescent↗
PubMed1980

[Postoperative and enteral feeding following abdominal surgery. Clinical study using a peptide diet].

To assess the value of early postoperative feeding with a chemically defined oligopeptide diet, 20 patients were examined after cholecystectomy. The patients were randomly selected for conventional treatment (water, electrolytes, and carbohydrates by intravenous route) or for feeding with the elementary diet (water, electrolytes, carbohydrates, fat short-chain peptides via a jejunal tube). The clinical and metabolic course of the ten patients fed with the elementary diet was good; they had a positive nitrogen balance by the second postoperative day. The results suggest that enteral tube feeding with a chemically defined oligopeptide diet is possible even in the early postoperative period after gastrointestinal operations and perhaps a definite alternative to parenteral nutrition.

Adult↗
PubMed1980

[The concentration of plasma amino acids during continuous infusion of Traumafusin into patients].

2 years ago we presented an amino acid solution with a special pattern for parenteral nutrition in the postoperative, posttraumatic period, which was adapted to this situation. The question arose, if this solution would be tolerated in patients with undisturbed metabolism. 10 male volunteers were infused with the amino acid solution (1 g amino acids/kg body weight/day) over a period of 3 days, and the concentration of the amino acids in plasma was measured at different times. It could be shown, that--without some exceptions--the homeostasis of the amino acids was not altered, that means that the proven amino acid solution can be used also in patients, who do not suffer from a post-aggression syndrome.

Adult↗
PubMed1980

[Safeguarding the postoperative protein balance. Clinical studies on intravenous feeding].

In a randomized controlled study the influence of a low concentrated amino acid-carbohydrate solution (PE 900 with 25 g x 1(-1) amino acids and 50 g x 1(-1) Polyols) on the nitrogen support is investigated in the postoperative metabolism. The solution has a low osmolality of approximately 600 mosm x kg-1 and is, therefore, applicable during longer time via peripheral veins. Nitrogen retention was with 68% rather good. The effect of the regimen on protein and amino acid status is measured and discussed in detail.

Amino Acids↗
PubMed1979

[Sorbitol and xylitol in post-operative infusion therapy (author's transl)].

The effect of a 24-hour continuous infusion of sorbitol in the recommended maximum dosage of 0.25 g . kg-1 . h-1 or of xylitol in the recommended maximum dosage of 0.125 g . kg-1 . h-1 on metabolic parameters was investigated in seven healthy adult men. The results demonstrate the continued applicability for longer than the recommended time as well as the acceptability of continuous infusion of polyols used clinically with combined solutions.

Adult↗