[Remembering Ismar Boas (1858 - 1938)]. / Erinnerung an Ismar Boas (1858 - 1938).

Ismar Boas is revered as one of the pioneers of modern gastroenterology. 75 years after his suicide due to Nazism it is appropriate to remember the great clinician and scientist. Moreover in a newly detected report from his hands some information on his thinking and handling of medical problems can be derived and his view of medial progress until today can be assessed.

[Effect of body posture and venous congestion on blood fat picture]. / Einfluss der Körperlage und der venösen Stauung auf die Blutfettspiegel.

The effects on the concentrations of total cholesterol, high-density lipids (HDL), triglycerides and glycerol of temporary venous occlusion during blood sampling and changing body posture (lying and standing) were measured on 20 healthy male volunteers (mean age 25 [21-27] years) with normal blood-lipid levels. Venous occlusion in the upper arm increased the concentration of lipids in the antecubital vein, by 8% after five min and 37% after 15 min. Initial levels were restored 10 and 15 min after the occlusion. Blood-lipid levels were similarly raised on standing up again. After 5 min they had risen by about 9%, after 15 min by 16%. After renewed recumbency the levels were up from the initial values by 5% after 10 min and by 3% after 15 min (P less than 0.01). The concentration of free glycerol on the whole varied randomly, but there was a statistically significant rise after 10 and 15 min standing. These results indicate that different techniques of blood sampling can influence the lipid concentrations in venous blood.

[Determining the size of the gallbladder with ultrasound--methods and results]. / Bestimmung der Gallenblasengrösse mit Ultraschall--Methoden und Ergebnisse.

By ultrasound undistorted two-dimensional pictures of gallbladder sections can be obtained. Determinations of size are performed either from one or from several well defined sonographic images. Studies of gallbladder contraction require at least 2 exposures: usually pictures of the "largest longitudinal section" are taken in the fasting state and 30 min after a stimulus (meal, hormones); for evaluation images are measured and compared. Estimations of gallbladder volume require at least 2 sonographic pictures of the gallbladder. We performed measurements in 250 patients. In most cases fasting volumes were between 10 and 25 ml and between 33 and 40 ml. There was a positive correlation with age and with body weight. Patients with cholelithiasis had larger gallbladder volumes than healthy controls. In 10 persons evacuation and filling of gallbladder after a meal was followed by serial measurements: maximal contraction was found between 20 and 45 min; original volumes were then reached after 180 min.

Assessment of cutaneous fat and body fat by ultrasound.

A new rapid and simple method is introduced to measure subcutaneous fat and evaluate total body fat. It is based on real-time ultrasound and requires equipment that is used in routine examination of subcutaneous structures, e.g., thyroid gland. Results from seven regions of skin in 100 subjects correlated well with total body weight, Broca's index, and deviation from average weight 0.02 greater than P greater than 0.001). Comparisons were also made with measurements of subcutaneous fat from skinfolds. There was an excellent correlation of values (P less than 0.001 in all experiments), although ultrasound results tended to be slightly higher. For calculation of total body fat, ultrasound values were converted by regression equations to "calculated skinfold thickness"; when applying established mathematical models for calculating body fat from skinfold thickness results were equal in both methods (P greater than 0.1).

Effect of dietary fiber on pancreatic lipase activity in vitro.

Lipase activity was measured in buffer solutions and in human duodenal juice after incubation with wheat bran, psyllium, pectin, lignin, guar gum, and cellulose. In the presence of wheat bran and pectin, activity of both enzymes was inhibited, whereas psyllium reduced only lipase activity in duodenal juice. The influence was relatively small, it measured between 12.0 and 34.8% if 12.5 g/L of dietary fiber were tested. Maximal effect required about 60 min of incubation. Inhibitory activity was destroyed after 30-min treatment with hydrochloric acid (pH 1.5) or cooking (95 degrees C). Inhibitors in pectin were more heat-resistant. It is concluded that dietary fibers exert inhibitory actions on pancreatic lipase; in man unfavorable effects could occur in exocrine pancreatic insufficiency.

Effect of dietary fiber on proteolytic pancreatic enzymes in vitro.

Chymotrypsin, trypsin, carboxypeptidase A and B, elastase and enterokinase activities were measured in buffer solutions and in human duodenal juice after incubation with wheat bran, cellulose, guar gum, pectin, psyllium and lignin. The different types of dietary fiber led to inhibition of enzymatic activity in most experiments, e.g., lignin could totally ablish the activity of isolated trypsin and chymotrypsin. Only in enterokinase was there no influence. Inhibition depended on incubation time; the effect was proportional to fiber concentration and inversely related to enzyme level. Treatment of fiber with hydrochloric acid (pH 1.5) and heat (95 degrees C) destroyed inhibitory activity in some experiments. The effect of lignin on one enzyme (trypsin) was reduced by the addition of another enzyme (chymotrypsin). It is concluded that dietary fiber could affect digestion by inhibiting proteolytic pancreatic enzymes.

[Studies of pre- and post-prandial abdominal sounds using an electronic analyzer]. / Untersuchung der prä- und postprandialen Bauchgeräusche mit einem elektronischen Analysator.

In 9 healthy persons abdominal sounds were analysed when fasting and over a period of 155 min after a meal containing 100 g of maltose or starch. Measurements included acoustical power in the following frequency-bands: 100-200 cps, 200-400 cps, 400-600 cps, 100-600 cps. In order to avoid disturbances due to variations in bowel-sounds energy-determinations were extended to 15 min. Uptake of carbohydrate meals was evaluated from serum glucose levels. During fasting measured powers were relatively low and reproducible. After eating there was a significant increase. Changes were more pronounced after starch, which required prior to intestinal uptake amylolytic degradation. After maltose, which is the principal absorbable degradation product of starch, increases were measureable in higher frequencies. Acoustical power at 100-200 cps was unchanged. We conclude that measurement of acoustical power at various frequencies can provide sensitive informations on processes related to movements in the abdominal cavity.

Guar gum and bile: effects on postprandial gallbladder contraction and on serum bile acids in man.

In a randomized cross-over study, 10 healthy volunteers received a fiber-depleted liquid mixed meal alone and, exactly 7 days apart, a combination with 15 g guar gum. Addition of the dietary fiber inhibited emptying of the gall bladder after 30 min to 7 (5-10) ml instead of 4 (3-6) ml (p less than 0.05) and delayed its refilling. Also the postprandial increase in conjugated serum bile acids was prevented by guar gum. The maximal postprandial blood glucose 30 min after ingestion of the meal was reduced from 120 (117-135) mg/dl to 110 (105-119) mg/dl (p less than or equal to 0.05) by guar gum. Serum insulin levels were unaffected by guar gum.--Our data suggest that the addition of guar gum to meals affects enterohepatic circulation of bile acids as well as digestion of carbohydrates.

[Inhibition of acetylcholinesterases--a relevant side effect of ranitidine?]. / Hemmung der Azetylcholinesterasen--ein relevanter Nebeneffekt von Ranitidin?

Ranitidine inhibited in a dose-dependent manner acetylcholinesterases from human erythrocytes and gastric mucosa. The concentration for half-maximal inhibition was 1,5 X 10(-6) and 1,4 X 10(-6) mol/l, which resembles levels seen during therapy. Inhibition was of competitive type, the inhibitory constant measured 1,6 X 10(-6) mol/l. Pseudocholinesterase in serum was also inhibited, however, the levels required were about 25 times higher. As a consequence from our in vitro findings a stimulation of cholinergic mechanisms in ranitidine treatment should occur, e. g. stimulation of glandular secretion or increase of gastrointestinal motility.

The inhibition of acetylcholinesterase and pseudocholinesterase by cimetidine.

Cimetidine inhibited cholinesterases from human blood serum, erythrocytes, brain and gastric mucosa in a dose-dependent manner. The median inhibitory concentrations ranged between 7.0 x 10(-4) mol/l and 2.1 x 10(-3) mol/l. The inhibition was of competitive type, the inhibitory constant of acetylcholinesterases in erythrocytes were found to be 8.5 x 10(-5) mol/l and of pseudocholinesterases in serum 8.5 x 10(-4) mol/l. A significance of our findings may be the explanation of side effects seen in cimetidine overdosage.

[Effect of bulk materials on the upper intestinal tract]. / Wirkungen der Ballaststoffe am oberen Intestinaltrakt.

Dietary fibers comprise a very heterogenous group of indigestible plant compounds. Whereas they exert only little effects on the recovery of the digestible parts of a meal they can modify various digestive processes. Most important seems to be the ability to inhibit digestion and absorption of carbohydrates, which enables better treatment of diabetics. The observation that serum cholesterol can be decreased by certain dietary fibers finds special interest also because of the possible reduction of risk for developing atherosclerosis. The various effects depend upon the physicochemical properties of the different fibers: they comprise the ability to bind water and organic substances, viscosity and cationic-exchange.

The effect of dietary fiber on pancreatic amylase activity in vitro.

In vitro the influence of wheat bran, guar gum, psyllium and lignin (2.5-50 g/l) on porcine pancreatic amylase (5-10 U/ml) was investigated. Enzyme activity was decreased in the presence of these substances with the exception of lignin. The reduction depended upon fiber concentration. In bran (50 g/l) it was 92 +/- 1%, in guar gum (25 g/l) 46.3 +/- 0.6%, and in psyllium (50 g/l) 41 +/- 1.4%. The effect was partly reversible if urea (1M) was added. Variations in pH (5.8-7.8) had no influence. Glucose formation from starch catalyzed by amylase was inhibited in the presence of bran, guar gum and psyllium, suggesting that the observed effect was also of functional significance.