Immunohistochemical identification of amyloid, using an anti-human serum amyloid P component (SAP) antibody, is possible in ruminants but not in dogs and cats

Amyloidosis represents a heterogenous group of diseases that have in common the deposition of fibrils composed of proteins of beta-pleated sheet structure, a structure which can be specifically identified by histochemistry using the Congo red or similar stains. Amyloid consists primarily of the amyloid fibrils but also of the amyloid P component (AP). This component, which is identical with the serum counterpart (SAP), is found in all types of human amyloid, and immunohistochemical identification of AP has been proposed as an adjunct to the universal, type-independent diagnosis of human amyloidosis. In the present study of animal amyloidosis, we compared the amyloid-specific Congo red stain with an immunohistochemical protocol using an anti-human SAP antibody for the identification of amyloid in formalin fixed tissue samples. The species and types of amyloidoses investigated were: (i) seven cows, one yak (Bos grunniens), and one sheep affected with amyloidosis of presumed AA type, (ii) one dog with a pancreatic endocrine tumour producing amyloid of presumed AIAPP type, (iii) two cats with presumed AIAPP-amyloidosis of the islets of Langerhans, one cat with presumed AA-amyloidosis, and one cat with an amyloid-producing odontogenic tumour. Intense immunostaining co-localized with amyloid, identified by its congophilia and green birefringence, using a protocol without any antigen retrieval in each of the seven cows, the yak and the sheep. The method seemed more sensitive in the ruminants than the Congo red stain, but was unable to detect amyloid in the dog and the cats regardless of the application of various antigen retrieval protocols. However, specific identification of amyloid still rests on the Congo red method or similar histochemical techniques.

A comparison of lipase and amylase in the diagnosis of acute pancreatitis in patients with abdominal pain

The clinical value of amylase and lipase measurement for the diagnosis of acute pancreatitis was evaluated in 253 patients presenting with acute abdominal pain. Acute pancreatitis was detected in 32 patients by computed tomography or ultrasound. In the serum samples collected on days 0-1 after the onset of symptoms, lipase was elevated in 100% and amylase in 95%. A 95% sensitivity/specificity was reached at a lipase cutoff near twofold above normal. The receiver-operating characteristics (ROC) showed similar curves for both enzymes, lipase being slightly superior to amylase. The ROC curves from days 2-3 demonstrated a much lower sensitivity/specificity of both enzymes. Lipase, however, was notably superior to amylase: at a sensitivity of 85% the specificity of lipase (amylase) was 82% (68%). In samples from days 4-5 the accuracy of the enzyme assays was even worse; at a sensitivity of 60% the specificity did not increase above 70%. The diagnostic value of simultaneous measurement of amylase and lipase was tested at different cutoffs in two groups: the OR group, in which one of the two parameters had to be elevated, and the AND group, in which both parameters had to be above normal. Combination of both parameters mainly improved the specificity of the assay (from 91 to 98% on days 2-3 and from 93 to 97% on day 4-5) but only when, in the OR group, twofold elevated amylase was combined with lipase. We conclude that the simultaneous determination of serum lipase and amylase marginally improved the diagnosis of acute pancreatitis in patients with acute abdominal pain, however, the sensitivity of the assay with samples collected 4-5 days after onset of the disease remained low.

Measurement of albumin synthesis in perfused rat liver using stable isotopes: [15N] hippurate as a measure of the intracellular [15N] glycine precursor enrichment

Rat livers were perfused by the non-recirculating technique with medium containing [15N] glycine and sodium benzoate. At various times, the 15N-concentration and the isotopic enrichment of perfusate hippurate, albumin, globulines, urea, creatinine and other fractions were measured by MS. Hippurate was used to represent the intracellular precursor pool for albumin synthesis. After start of glycine administration the ratio APE product/APE precursor pool had reached approximately maximal values. After 30 min, the precursor pool size and its use in protein synthesis decreased due to amino-acid-deficient perfusion with no further decrease between 30 and 105 min. Additionally, rates of protein synthesis were determined. The albumin synthesis rate was 3.27 mg/g liver weight per hour.

Intestinal absorption of D-xylose in the early post-operative period

To assess intestinal absorption in the early post-operative period, portal and subclavian vein catheters were implanted into 8 pigs. For direct d-xylose infusion into the upper small intestine a feeding tube was inserted via a gastrostomy. Four control animals (Group 1) underwent an open and close laparotomy after catheter and tube implantation. Four pigs (Group 2) underwent a standardised ileocoecostomy. At 6, 24, 36, 48 and 72 h after surgery, d-xylose was infused into the small intestine in both groups of animals. After single-dose administration the absorption kinetics were measured in the pre- and post-hepatic blood compartment. With increasing time after operation the rate and extent of d-xylose absorption returned towards normal but there were significant differences in the d-xylose kinetics between the two groups. The absorption kinetics and d-xylose uptake recovered more rapidly in the control group than in those who underwent ileocoecostomy. Effective enteral feeding in controls after 36 h was achieved, but in Group 2 was delayed until 48 h post-operatively. Absorption capacity returned to normal after 48 h in controls and after 72 h in Group 2.

[Studies of solutions with various branched-chain amino acid contents on protein metabolism in the postoperative period. 1. A 15N tracer kinetic animal model for evaluating the effect of parenteral amino acid administration on nitrogen metabolism]

We were able to estimate nitrogen or protein metabolism on the basis of a 15N metabolic model that delivered a high amount of data during a parenteral nutrition period over 72 h. We describe the basic principles of the necessary N or 15N-analyses in blood, as well as in sera, in urine, in tissues of selected organs and in hepatocytes. This 15N-metabolic model allows the estimation of the utilization of amino acid infusion solutions. Because of the great similarity of parameters of the N or protein turnover between man and pig it is possible to provide relevant information for the clinical practice regarding amino acid infusion solutions.

[Postoperative small intestine absorption--principles for enteral nutrition]

The intestinal absorption of nutrients is disturbed to an extent dependent on the degree of trauma in the immediate postoperative period. In a clinical study, the d-xylose absorption was investigated in 3 groups of patients after cholecystectomy. On the day of surgery a significant restriction of the absorption could be observed after intraduodenal administration. After gastric and duodenal administration of d-xylose and simultaneous enteral early nutrition a significant restriction of absorption could be observed on the day surgery was carried out. Optimal conditions for early nutrition can be achieved by combining intraduodenal feeding and a continuous decompression of the stomach. In cases of a gastric drainage an improvement of the postoperative absorptive function can be supported by the results of the nitrogen balance. In 4 pigs (type: country race) the step-by-step normalization of the absorptive kinetics could be demonstrated after catheters were implanted into the portal and subclavian veins.

Evaluation of protein metabolism in clinical practice

The application of stable isotopes creates further possibilities for our understanding of the metabolism. New concepts especially for non-invasive diagnostic procedures could be developed. An important step in our research program was the performing of a 1-year experiment on a volunteer. On the basis of a 10-pool model we received a lot of informations. Based on this knowledge we developed 2 simplified methods for calculating whole body protein turnover. Knowing the problems with whole body protein calculations we intensified our intentions for determining the protein enrichment in organs and isolated cells (hepatocytes), estimating at the same time the precursor pool in the cells. Of special importance was an extensive study, wherein all those 15N-estimations were performed we are able to do up to now. We calculated whole body protein, but especially we studied the enrichment of the cellular protein fractions in hepatocytes, of plasmaproteins, and of the intracellular precursor pool. This study is the base for further tracer investigations.

[Value of various amino acid mixtures for the treatment of chronic liver damage]

A reproducible liver lesion was caused in 28 pigs by intermittent, intraperitoneal administration of thioacetamide. The morphological degree of the liver lesion was checked by histological investigations (material drawn from the liver by biopsy). During a 3-day infusion period a so-called liver solution (Aminofusin hepar) was given to one group of animals, a normal solution (Infesol) to a second group, and only an electrolyte infusion solution under oral nutrition ad libitum to a third one. The solutions were labelled with (15N) glycine. The amounts of total N, total 15N, 15N with single non-protein fractions, a number of enzymes of 15N incorporated into the liver protein were measured in urine, and the following points were established: 1. The catabolic situation of metabolism is eliminated both by the so-called normal solution and the specific amino acid solution. The two mixtures of L-amino acids thus have a nutritive effect. 2. The toxic liver lesion is an indication for parenteral nutrition. Oral nutrition alone is not sufficient. 3. The so-called liver solution influences the liver metabolism of the protracted liver lesion more than the so-called normal solution does, and considerably more than an electrolyte infusion solution under oral nutrition ad libitum.

[Assessment of risk status using nutrition diagnostic studies in surgical patients. 1. Determination of preoperative risk status in patients with stomach cancer]

The diagnosis of the nutritional state is an essential component in determining the risk in patients with carcinoma of the gastrointestinal tract. Based on the results of multivariate, statistical analyses of numerous biochemical, anthropometric and immunologic parameters in 63 patients with gastric carcinoma, we can now simplify the determination of the nutritional state considerably. With the help of cluster analysis and together with clinical aspects, the nutritional state can be divided into 2 groups ('normal' and 'disturbed'), in contrast to the former classification ('normal' and several degrees of disturbed). Using discrimination analysis, a combination of parameters was found which allows a sufficiently good classification of subjects into either the 'normal' group or the 'disturbed' group, and in this way characterizes the nutritional state. Classification of the patients is accurate in 97% of the cases. 6 practically relevant parameters were determined with the discrimination analysis: serum albumin, serum transferrin, hemoglobin, upper arm circumference, triceps skin fold thickness, and the intracutaneous skin test quotient. The nutritional quotient, EQ2, can be determined from these values (in comparison to the nutritional quotient, EQ1, which is based on the 33 point evaluation scale), thus enabling a quantification of the nutritional state. The use of only individual parameters yields major differences from the results obtained with 6 parameters. However, a relation between the nutritional state and the existing immuno-competence can be suspected when the results - especially of the skin test reactions - are in agreement with the results of the lymphocyte transformation. The test results of cell-mediated immunity in particular represent the extent of a reduced immunological reaction as opposed to the results of humoral immunity. Inclusion of less complex immunological investigation procedures must be reserved for future studies. The determination of daily urea production (urea production rate; dependent on protein supply) can be implemented as a practically relevant and reliable supplemental test for the evaluation of the existing metabolic state.

Erfassung der Gefährdungslage mit Hilfe ernährungsdiagnostischer Untersuchungen bei chirurgischen Patienten

Die Diagnostik des Ernährungszustands ist ein wesentlicher Bestandteil der Erfassung der Gefährdungslage bei Patienten mit Karzinomen des Verdauungstrakts. Nach den Ergebnissen multivariater statistischer Analysen zahlreicher biochemischer, anthropometrischer und immunologischer Parameter bei 63 Patienten mit Magenkarzinom können wir heute die Bestimmung des Ernährungszustands wesentlich vereinfachen. Mit Hilfe der Clusteranalyse und zusammen mit klinischen Aspekten kann der Ernährungszustand im Gegensatz zur bisherigen Klassifizierung («normal» und mehrere Störungsgrade) in 2 Gruppen («normal» und «gestört») eingeteilt werden. Mit Hilfe der Diskriminanzanalyse wurde eine Merkmalskombination gefunden, die eine hinreichend gute Diskrimination der Probanden in eine der Gruppen «normal» und «gestört» zuläβt und damit den Ernährungszustand charakterisiert. Die Zuordnung der Patienten trifft in 97% der Fälle zu. Bei der Diskriminanzanalyse konnten 6 praxisrelevante Merkmale ermittelt werden, und zwar Serumalbumin, Serumtransferrin, Hämoglobin, Oberarmmuskelumfang, Trizepshautfaltendicke und der intrakutane Hauttestquotient. Daraus kann der Ernährungsquotient EQ₂ ermittelt werden (im Vergleich zum Ernährungsquotienten EQ₁ nach dem 33-Punkte-Bewertungsschema), womit eine Quantifizierung möglich ist. Die Verwendung nur einzelner Parameter ergibt gröβere Differenzen von den gewonnenen Ergebnissen mit 6 Parametern. Allerdings kann durch die Ergebnisse besonders der Hauttestreaktionen übereinstimmend mit den Ergebnissen der Lymphozytentransformation ein Zusammenhang zwischen Ernährungszustand und der aktuellen Immunokompetenz vermutet werden. Die Untersuchungsergebnisse der zellvermittelten Immunität repräsentieren insbesondere das Ausmaβ einer herabgesetzten immunologischen Reaktion gegenüber den Ergebnissen der humoralen Immunität. Die Einbeziehung weniger aufwendiger immunologischer Untersuchungsverfahren bleibt zukünftigen Erhebungen vorbehalten. Als eine praxisrelevante und verläβliche Zusatzuntersuchung für die Beurteilung der aktuellen Stoffwechsellage kann die Bestimmung der täglichen Harnstoffproduktion (Harnstoffproduktionsrate; in Abhängigkeit von der Eiweiβzufuhr) herangezogen werden.

[Nutritional therapy in cancer patients of advanced age]

The reduced nutritional state of cancer patients can be influenced by a purposeful feeding, which decreases the rate of complicating factors and diminishes side effects resulting from the often aggressive cancer therapy. Multimorbidity, a change in the need for nutritive substances in advanced age and senile functional changes in numerous organs make it a necessity to adapt elderly cancer patients trophotherapy to these conditions.

[Methodological aspects of the determination of nitrogen metabolism parameters from 15N-tracer experiments on swine based on nitrogen metabolism models. 2. Calculation of N metabolism parameters from the time of urinary excretion of 15N]

After a 45-hour infusion of 15N-lysine and 15N-glycine resp. with pigs of 25 kg live weight, the infusion of the tracer was disrupted and a 3-day reduction phase was made part of the experiment. The N-metabolism parameters such as protein synthesis and decomposition quotas were calculated on the basis of the temporal development of 15N-amounts excreted in urine. The labelling and reduction phases were evaluated simultaneously. By means of including the total N-amount of the animal body the balance calculation becomes more stable. The possible influence of the tracer amino acid in connection with the 3-pool-model is discussed on the basis of the ascertained parameters.