Recovery after long-term summer drought: Hydraulic measurements reveal legacy effects in trunks of Picea abies but not in Fagus sylvatica

Climate change is expected to increase the frequency and intensity of summer droughts. Sufficient drought resistance, the ability to acclimate to and/or recover after drought, is thus crucial for forest tree species. However, studies on the hydraulics of mature trees during and after drought in natura are scarce. In this study, we analysed trunk water content (electrical resistivity: ER) and further hydraulic (water potential, sap flow density, specific hydraulic conductivity, vulnerability to embolism) as well as wood anatomical traits (tree ring width, conduit diameter, conduit wall reinforcement) of drought-stressed (artificially induced summer drought via throughfall-exclusion) and unstressed Picea abies and Fagus sylvatica trees. In P. abies, ER indicated a strong reduction in trunk water content after 5 years of summer drought, corresponding to significantly lower pre-dawn leaf water potential and xylem sap flow density. Vulnerability to embolism tended to be higher in drought-stressed trees. In F. sylvatica, only small differences between drought-stressed and control trees were observed. Re-watering led to a rapid increase in water potentials and xylem sap flow of both drought-stressed trees, and to increased growth rates in the next growing season. ER analyses revealed lower trunk water content in P. abies trees growing on throughfall-exclusion plots even 1 year after re-watering, indicating a limited capacity to restore internal water reserves. Results demonstrated that P. abies is more susceptible to recurrent summer drought than F. sylvatica, and can exhibit long-lasting and pronounced legacy effects in trunk water reserves.

Subchronic and Chronic Toxicity/Carcinogenicity Feeding Studies with Lactitol in Rats

The toxicity and possible carcinogenicity of lactitol, a lactose-derived reduced calorie sugar substitute, were examined in Wistar Cpb:WU rats. In a first 13-week study, groups of 10 weanling rats of each sex were fed diets containing 0, 5, 10, or 20% lactitol, or 25% lactose. In a second 13-week study, groups of 20 rats of each sex received diets with 0, 10, or 20% lactitol, or 25% lactose starting from an age of 3 months. In a lifetime toxicity/cancerogenicity study with in utero exposure, groups of 50 rats of each sex consumed diets with 0, 2, 5, or 10% lactitol, or 20% lactose for 130 weeks. Satellite groups of 10 rats/group received the same diet but were sacrificed after 53 weeks. Subchronic and chronic ingestion of lactitol and lactose was generally well tolerated and an effect on mortality rate was not seen. Body weight gains were slightly decreased in a dose-related manner in all experiments. Dose-related cecal enlargement was observed consistently with lactitol and lactose. Examinations for hematological parameters and urine composition did not reveal any treatment-related abnormalities. The clinical chemistry examinations revealed increased plasma alkaline phosphatase (AP) levels in rats fed 5 or 10% lactitol, or 20% lactose. Slight (microscopic) cytoplasmic alterations in the staining pattern of hepatocytes were observed in the first but not the second 13-week study in a number of male rats of the 10 and 20% lactitol groups. In the chronic study, a statistically significant increase in bile duct hyperplasia was noted in female rats fed 5 or 10% lactitol, or 20% lactose. Measurement of femur calcium content in terminated female rats revealed a dose-related, yet statistically nonsignificant decrease in the lactitol groups and lowest levels in the 20% lactose group. The histopathological examination of rats treated with lactitol and lactose for their lifetime showed an increased incidence of (1) pelvic nephrocalcinosis (5% lactitol females, and 10% lactitol and 20% lactose males and females), (2) adrenomedullary proliferative changes (10% lactitol and 20% lactose males), and (3) hyperplastic and neoplastic changes of Leydig cells (10% lactitol and 20% lactose males). Results from other studies suggest that nephrocalcinosis and adrenal medullary proliferative disease represent sequelae of a chronic, treatment-related hyperabsorption of calcium which does not occur in man. The mechanism of the testicular effect is not yet identified. However, lactitol gave completely negative results in standard tests for mutagenicity and clastogenicity, and no testicular effects or other neoplastic response was observed in lactitol-fed mice. Since Leydig cell tumors occur in humans at an extremely low rate despite the ingestion of substantial amounts of lactose with ordinary meals, the observation made in rats lacks apparent relevance for man.

Subchronic Toxicity Study of Lactitol in Dogs

The subchronic oral toxicity of lactitol was examined by feeding the test substance at dietary levels of 0, 5, 10, and 15% to groups of 6 male and 6 female dogs for 26 weeks. A comparison group received a diet containing 15% lactose. Although the dogs gradually were adapted to the high doses of the test compounds, diarrhea was observed in the dogs fed 10 and 15% lactitol, and 15% lactose. The diarrhea in the lactose group was less severe than in the 10% lactitol group. Body weight did not show treatment-related differences between the groups. Food intake was slightly higher in the lactitol groups than in the controls. Hemoglobin content (Hb), packed cell volume (PCV), and red blood cell counts (RBC) were slightly lower in dogs of the 15% lactitol group and the 15% lactose group. No other hematological parameters exhibited differences between the various treatment groups. Plasma glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), protein, albumin, glucose, and urea showed no treatment-related differences. However, plasma alkaline phosphatase (AP) tended to be lower in the females of all lactitol groups from day 0 to the end of the study. Transient decreases in plasma calcium and potassium levels were seen in lactitol- and lactose-fed female dogs. Semiquantitative urine analysis did not reveal any abnormalities. There was no impairment of the function of the liver or kidneys in any of the groups. The absolute and relative weights of the cecum, filled as well as empty, were relatively high in males of all lactitol groups and in females of the 10 and 15% dose groups. The weight of the colon and the small intestines, which were determined in males only, were increased in the 5 and 15% lactitol groups. Gross and microscopic examination did not reveal any pathological change that could be attributed to the feeding of lactitol or lactose. It is concluded that under the conditions of the study, daily doses of up to 4.2–6.8 g/kg b.w. are tolerated without obvious signs of toxicity.

Multigeneration Reproduction Study of Lactitol in Rats

Lactitol is a disaccharide sugar alcohol (polyol) which holds promise as a reduced calorie, noncariogenic sugar substitute. In a multigeneration reproduction study, lactitol was fed to Wistar-derived Cpb:WU rats of both sexes throughout three successive generations at dietary concentrations of 0, 2, 5, and 10%. A comparison group receiving a diet with 20% lactose was included during the F., generation. The initial mating comprised 20 male and 40 female rats per group. For subsequent matings, 10 males and 20 females were used. In each generation, two litters were reared until they were at least 3 weeks old. Fertility was uniformly high in all treatment groups throughout the study and the feeding of lactitol was not associated with any adverse effects on fertility and reproductive performance. However, growth rates and survival were slightly decreased in pups of the 10% lactitol group, except in F3 litters where no effect of lactitol on survival was seen. In the 20% lactose group of the F, generation, a similar growth retardation and decreased survival was seen. The second litter of third-generation rats (F3b) was subjected to gross and histopathological examination 4 weeks after weaning. F3b rats fed 5 or 10% lactitol showed cecal enlargement which was not associated with any morphological alterations and which is commonly seen in rodents fed polyols or slowly digestible carbohydrates. In some F3b males of all dosage groups, an opaque appearance of the liver cell cytoplasm was noted. However, this effect was not dose related and was not accompanied by any other hepatic changes in the lactitol groups. Since this phenomenon was not seen in older rats or after chronic administration of lactitol, it was considered to be a transient manifestation of an altered metabolism in young rats. All other histopathological findings were equally distributed between control and test animals, or occurred in one or a few rats only. It is concluded that lactitol administered in the diet to three successive generations of rats at levels up to 10%, has no adverse effects on reproductive performance in either sex. The slight developmental delay which occurred in some generations, has been observed earlier with other polyols and may be attributed to the poor digestibility of these compounds.

Chronic Toxicity and Carcinogenicity Study of Lactitol in Mice

Lactitol is a sweet-tasting disaccharide sugar alcohol with potential applications as a reduced calorie sugar substitute. In a chronic toxicity/carcinogenicity study, groups of 50 male and 50 female Cpb:Swiss random (SPF) mice received diets containing 0, 2, 5, and 10% lactitol for 104 weeks. The test compound was added to the diet at the expense of sucrose. The treatment started after a 5-day period during which the weanling mice were adapted to the basal diet. In the highest dosage group, the mean daily intake of lactitol was about 11 g/kg b.w. and 7.5 g/kg b.w. for adult male and female mice, respectively. Lactitol was generally well tolerated. Mean body weights and mortality were not affected by the treatment. Semiquantitative urine analysis and examination of urinary sediment revealed no abnormalities. With the exception of the filled or empty cecum which exhibited a significantly higher weight in the 10% lactitol group and, to a lesser extent, also in the 5% lactitol group, the weight of all other organs was not affected by the treatment. Nonneoplastic and preneoplastic changes were about equally distributed amongst the controls and top-dose group. Neoplastic lesions were in no instance related to the feeding of lactitol. Contrary to observations made with other polyols, nephrocalcinosis did not occur more frequently in lactitol-fed mice. It is concluded that the feeding of lactitol at dietary levels of up to 10% to mice throughout their lifetime failed to show carcinogenic effects or any other sign of toxicity. The only observed treatment-related effect was an enlargement of the cecum which lacks toxicological relevance for humans and which is a well-known consequence of the feeding of slowly digestible compounds in mice and rats.

Empowerment and satisfaction in a multinational study of routine clinical practice

OBJECTIVE

Decision-making between mental health clinicians and patients is under-researched. We tested whether mental health patients are more satisfied with a decision made (i) using their preferred decision-making style and (ii) with a clinician with the same decision-making style preference.

METHOD

As part of the CEDAR Study (ISRCTN75841675), a convenience sample of 445 patients with severe mental illness from six European countries were assessed for desired clinical decision-making style (rated by patients and paired clinicians), decision-specific experienced style and satisfaction.

RESULTS

Patients who experienced more involvement in decision-making than they desired rated higher satisfaction (OR=2.47, P=0.005, 95% CI 1.32-4.63). Decisions made with clinicians whose decision-making style preference was for more active involvement than the patient preference were rated with higher satisfaction (OR=3.17, P=0.003, 95% CI 1.48-6.82).

CONCLUSION

More active involvement in decision-making than the patient stated as desired was associated with higher satisfaction. A clinical orientation towards empowering, rather than shared, decision-making may maximise satisfaction.

Subchronic (13-week) oral toxicity study of alpha-cyclodextrin in dogs

The oral toxicity of alpha-cyclodextrin (alpha-CD) was examined in a 13-week feeding study in which groups of Beagle dogs received alpha-CD in the diet at concentrations of 0 (control), 5, 10, or 20% (4 dogs/sex/group). No treatment-related changes were noted in behavior or appearance of the dogs and no mortalities occurred. Diarrhea occurred in all alpha-CD groups. The incidence and severity of diarrhea increased with increasing dietary levels of alpha-CD and was more pronounced in males than females. Nonetheless, all dogs remained in good health and gained weight. Food intake was slightly increased and food efficiency was slightly decreased in the 20% alpha-CD group. However, these changes did not reach statistical significance. No treatment-related differences were observed with respect to ophthalmoscopic examinations, hematological parameters, clinicochemical analyses of the plasma, and semiquantitative urine analyses. Only the urinary pH was slightly below control levels in males (p > 0.05) and females (p < 0.05) of the 20% alpha-CD group. No abnormalities were seen at necropsy that could be attributed to the treatment. The organ weight data revealed cecal enlargement in the 10 and 20% alpha-CD groups (significant only in males). The relative weight of the colon was also slightly increased in the 10 and 20% alpha-CD groups (significant only in females of the 10% alpha-CD group). On microscopic examination, no treatment-related alterations were observed in any of the various organs and tissues. In conclusion, transient diarrhoea, enlargement of the cecum and colon and a slightly increased acidity of the urine were the only treatment-related effects. These changes are well-known physiological responses to the presence of high amounts of not digested, fermentable carbohydrates in the lower gut. They are known to be reversible on cessation of the treatment and are not associated with histological alterations of the intestinal tissues. It is concluded, therefore, that the high dose level, at which the male and female dogs consumed about 9.8 and 10.4 g alpha-CD/kg bw/d, respectively, is the NOAEL of this 13-week toxicity study.

Subchronic oral toxicity studies with alpha-cyclodextrin in rats

The toxicity of alpha-cyclodextrin (alpha-CD), a cyclic polymer of six alpha-1,4-linked glucopyranosyl units with potential applications as a food ingredient, more specifically a water-soluble dietary fiber, was examined in a 4-week range finding study and a 13-week oral toxicity study in rats. In the 4-week study, the test substance was administered to groups of Bor:WISW(SPF;Cpb) rats at dietary levels of 0, 1, 5, and 15% (5 rats/sex/group). An additional group received a diet with 5% beta-CD. In the 13-week study, groups of Crl:(WI)WU Br rats received diets with 0, 1.5, 5, or 20% alpha-CD. An additional group received a diet with 20% lactose (20 rats/sex/group). Satellite groups of 10 rats/sex were attached to the control, 20% alpha-CD and 20% lactose group. Following the 13-week treatment period, these satellite groups were kept on a standard, cereal-based rodent diet for a 4-week recovery period. Parameters measured during the two studies included clinical signs, body weights, food and water intake, hematological and clinicochemical parameters, and organ weights as well as gross and histopathological observations at necropsy. In the 13-week study, ophthalmoscopic examinations as well as urine and feces analyses were also conducted. There were no treatment-related mortalities in either study. In the 4-week study, persistent diarrhea was the most prominent, treatment-related effect observed in the animals of the 15% alpha-CD group especially in the male animals. In association with this effect, food consumption and food conversion efficiency were decreased. In line with observations from studies with other low-digestible, yet fermentable carbohydrates, the weight of the full and empty cecum was increased significantly in the 5% alpha-CD, 5% beta-CD, and 15% alpha-CD group. The reduced relative liver weights (in males and females) and the significantly increased relative testes weight which were observed in the 15% alpha-CD group, were attributed to the impaired nutritional condition (due to diarrhea) and the reduced body weight of the animals of this group, respectively. Microscopic examination of the main organs did not reveal pathological alterations that could be attributed to the alpha-CD treatment. In the 13-week study, soft stool and infrequent mild diarrhea were observed only during the first 2-3 weeks in the 20% alpha-CD and 20% lactose group (mainly male animals). Accordingly, body weights were reduced in males of the 20% lactose group throughout the study and in the 20% alpha-CD group during the last week of the study. Food intakes were slightly increased in the 20% alpha-CD group and the food conversion efficiency, was significantly reduced in males, but not females, of the 20% alpha-CD and 20% lactose group. There were no treatment-related changes of hematological parameters. In line with similar observations from studies on other low-digestible carbohydrates, the urinary pH was decreased and urinary calcium levels increased in the 20% alpha-CD and 20% lactose group. Similarly, the fecal dry weight and nitrogen output was increased in these groups. At termination of the treatment, significantly in creased cecum weights (full and empty) were observed in the 5 and 20% alpha-CD groups and the 20% lactose group. The relative (not absolute) weight of the spleen was significantly increased in males of the 20% alpha-CD group. In the 20% lactose group, the relative weights of the spleen and liver (females) and the testes, brain, and adrenals (males) were significantly increased. The histopathological examination of these and all other organs and tissues did not reveal any abnormalities that could be attributed to the alpha-CD or lactose treatment. In conclusion, the ingestion of alpha-CD for 13-weeks at dietary levels of up to 20% (corresponding to intakes of 12.6 and 13.9 g/kg bodyweight/d in male and female rats, respectively) did not produce any signs of toxicity or adverse effects.

Embryotoxicity and teratogenicity study with neohesperidin dihydrochalcone in rats

The embryotoxicity/teratogenicity of neohesperidin dihydrochalcone (NHDC) was examined in Wistar Crl:(WI)WU BR rats. NHDC was fed at dietary concentrations of 0, 1.25, 2.5 or 5 to groups of 28 mated female rats from day 0 to 21 of gestation. At Cesarean section 25, 22, 23, and 23 rats were found to be pregnant in the control, low-, mid-, and high-dose group, respectively. The NHDC treatment was well tolerated and all animals survived till the end of the study. Body weights (bw) and body weight gains did not differ between controls and NHDC treatment groups. The intake of NHDC was 0.8-0.9, 1.6-1.7, and 3.1-3.4 g/kg bw/day for the low-, mid-, and high-dose group, respectively. Except for cecal enlargement, there were no changes observed at necropsy which could be related to the NHDC treatment. All dams had viable fetuses. The fecundity and gestation index, the number of corpora lutea, implantation sites, live and dead fetuses, early and late resorptions, pre- and post-implantation losses, and sex-ratio were not affected by the treatment. There were no differences for the mean weight of the gravid and empty uterus, ovaries, and placenta between the NHDC treatment groups and the controls. Examination of the fetuses for external, visceral, and skeletal changes did not reveal any fetotoxic, embryotoxic or teratogenic effects of NHDC. In conclusion, no adverse effects were observed at NHDC levels of up to 5% of the diet, the highest dose level tested, at which the rats consumed about 3.3g/kg body weight/day. The observed cecal enlargement is a well-known physiological, adaptive response to the ingestion of high doses of a low-digestible substance and is generally accepted to lack toxicological relevance.

Safety assessment of gamma-cyclodextrin

Gamma-cyclodextrin (gamma-CD) is a cyclic alpha-(1,4)-linked oligosaccharide consisting of eight glucose molecules. Like other cyclodextrins, gamma-CD can form inclusion complexes with a variety of organic molecules because the inner side of the torus-like molecule is less polar than the outer side. In foods, gamma-CD may be used as a carrier for flavors, vitamins, polyunsaturated fatty acids, and other ingredients. It also has useful properties as a stabilizer in different food systems. The daily intake from all its intended uses in food at highest feasible concentrations has been estimated at 4.1g/person/day for consumers of gamma-CD containing foods. The present review summarizes the safety data of gamma-CD. The toxicity studies consist of standard genotoxicity tests, subchronic rat studies with oral and intravenous administration of gamma-CD for up to 3 months, a subchronic (3-month) toxicity study in dogs, a (1-year) oral toxicity study in rats, and embryotoxicity/teratogenicity studies in rats and rabbits. In the studies with oral administration, gamma-CD was given at dietary concentrations of up to 20%. All these studies demonstrated that gamma-CD is well tolerated and elicits no toxicological effects. Metabolic studies in rats showed that gamma-CD is rapidly and essentially completely digested by salivary and pancreatic amylase. Therefore, the metabolism of gamma-CD closely resembles that of starch and linear dextrins. A human study with ingestion of single doses of 8 g gamma-CD or 8 g maltodextrin did not reveal a difference in gastrointestinal tolerance of these two products. An interaction of ingested gamma-CD with the absorption of fat-soluble vitamins or other lipophilic nutrients is not to be expected because the formation of inclusion complexes is a reversible process, gamma-CD is readily digested in the small intestine, and studies with beta-CD, a non-digestible cyclodextrin, have shown that the bioavailability of vitamins (A, D, and E) is not impaired. On basis of these studies it is concluded that gamma-CD is generally recognized as safe (GRAS) for its intended uses in food.

Embryotoxicity and teratogenicity study with α-cyclodextrin in rats

The embryotoxicity/teratogenicity of alpha-cyclodextrin (alpha-CD) was examined in Wistar Crl:(WI)WU BR rats. alpha-CD was fed at dietary concentrations of 0, 1.5, 5, 10, or 20% to groups of 25 pregnant female rats from day 0 to 21 of gestation. An additional group received a diet with 20% lactose. The additions to the diet of alpha-CD and lactose were made at the expense of pregelatinized potato starch. Body weight as well as food and water intake were recorded during the treatment period. The rats were killed on day 21 and examined for standard parameters of maternal reproductive performance. The fetuses were examined for external abnormalities, body weight and crown rump length. Fetuses were examined for skeletal and visceral abnormalities. Generally, alpha-CD was well tolerated and no deaths occurred in any group. Weight gain and food consumption were similar in all groups during gestation, except for a slightly yet significantly increased food intake in the 20% alpha-CD group from day 6 to 21. Water intake was similar in all alpha-CD groups; in the lactose group, it was significantly higher than in the controls. Maternal reproductive performance was not affected by the alpha-CD treatment. Examination of the fetuses for external, visceral and skeletal changes did not reveal any fetotoxic, embryotoxic, or teratogenic effects of alpha-CD. In conclusion, no adverse effects were observed at alpha-CD intakes of up to 20% of the diet, the highest dose level tested at which the rats consumed about 13 g/kg bw/day.

Embryotoxicity and teratogenicity study with α-cyclodextrin in rabbits

In a standard embryotoxicity/teratogenicity study, alpha-cyclodextrin (alpha-CD) was administered to groups of sixteen, artificially inseminated New Zealand White rabbits at dietary concentrations of 0, 5, 10, or 20%. An additional group received a diet containing 20% lactose. Treatment started on day 0 of gestation and ended on day 29 when the animals were killed. Except for the occurrence of transient diarrhoea in one rabbit of the 20% alpha-CD group for a few days, the treatment was well tolerated. A reduced food intake in the 20% alpha-CD group during the first week of treatment resulted in a reduced weight gain from day 0 to 12 of the study. However, the difference to the controls was not significant and at termination of the study body weights were similar in all groups. Even at the highest dose level, which corresponds to an intake of 5.9-7.5 g/kg bw/day, no signs of maternal toxicity were observed. Maternal reproductive performance was not affected by the treatment. Uterine weight, placental weight, fetal weight, number of fetuses, sex ratio, number of implanation sites, resorptions, and corpora lutea did not differ among the groups. Visceral and skeletal examinations of the fetuses did not reveal any malformations, anomalies or variations that could be attributed to treatment. It was concluded that dietary alpha-CD is generally well tolerated by pregnant rabbits, has no adverse effect on maternal reproductive performance and is not embryotoxic, fetotoxic, or teratogenic at dietary concentrations of up to 20%, the highest dose level tested.

Safety evaluation of an α-cyclodextrin glycosyltranferase preparation

Alpha-cyclodextrin glucosyltransferase (alpha-CGTase, EC 2.4.1.19) is an amylolytic enzyme used for the production of alpha-cyclodextrin (alpha-CD), a novel, soluble dietary fiber, from food-grade starch. The safety of an alpha-CGTase preparation obtained by batch fermentation from a recombinant strain of Escherichia coli K12 harboring the alpha-CGTase gene from Klebsiella oxytoca strain M5a1 was examined. In a 13-week subchronic toxicity study in rats, the administration by gavage of the alpha-CGTase preparation at levels of up to 20 ml/kg bw/day, corresponding to a total organic solids dosage of 260 mg/kg bw/day, did not cause any systemic toxic effect. Some signs of irritation were observed in the respiratory tract which occurred, however, in one sex only and/or were not dose-related. Accordingly, these changes were considered to be an unspecific consequence of the reflux and aspiration of the dosing solution. There was no evidence of a genotoxic activity in Ames tests and a chromosome aberration test in cultured human lymphocytes. It is concluded that the examined alpha-CGTase preparation is safe when used for the production of alpha-CD.

Disposition of 14C-α-cyclodextrin in germ-free and conventional rats

The absorption, disposition, metabolism, and excretion of uniformly (14)C-labeled alpha-cyclodextrin ((14)C-alpha-CD) was examined in four separate experiments with Wistar rats. In Experiment 1, (14)C-alpha-CD (25 microCi, 50 mg/kg bw) was administered intravenously to four male and four female conventional rats. In Experiment 2, (14)C-alpha-CD (25 microCi, 200 mg/kg bw) was given by gavage to four male and four female germ-free rats. In Experiments 3 and 4, (14)C-alpha-CD was given to groups of four male and four female conventional rats by gavage at different dose levels (100 microCi, 200 mg/kg bw; 25 microCi, 200 and 100 mg/kg bw). In all experiments, (14)C was measured in respiratory CO(2), urine, and feces over periods of 24-48 h, and in the contents of the gastrointestinal tract, blood, main organs, and residual carcass at termination of the experiments. The chemical identity of the (14)C-labeled compounds was examined by HPLC in blood (Experiment 1), urine (Experiments 1-4), feces (Experiments 2-4), and samples of intestinal contents (Experiments 2 and 4). Recovered (14)C was expressed as percentage of the administered dose. Experiment 1 showed that intravenously administered alpha-CD is excreted rapidly with urine. During the first 2h after dosing, plasma (14)C levels decreased rapidly (t(1/2), 26 and 21 min in male and female rats, respectively). About 13% of the administered (14)C dose (range 4.6-30.6) was detected in the feces, respiratory CO(2), organs, and carcass at the end of the experiment, i.e., 24 h after dosing. The presence of about 1.9% in the intestinal contents and feces suggests that a certain fraction of systemic alpha-CD is eliminated with the bile or saliva. Conclusive evidence, either positive or negative, for a hydrolysis and further metabolism of a small fraction of the administered alpha-CD by the enzymes of the mammalian body could not be gained from this experiment. Upon oral administration of (14)C-alpha-CD to germ-free rats (Experiment 2), about 1.3% of the label expired as CO(2) within 24 h. In the urine collected from 0 to 8 h after dosing, (14)C-alpha-CD was the only radiolabeled compound detected. The amounts of alpha-CD detected in the urine suggest that on average about 1% of an oral dose is absorbed in rats during small-intestinal passage. In conventional rats (Experiments 3 and 4), a delayed appearance of respiratory (14)CO(2) was observed which is attributed to the non-digestibility of alpha-CD and its subsequent microbial fermentation in the cecum and colon. In the urine collected at 4 h after dosing, a small amount of unchanged (14)C-alpha-CD was detected which confirms that about 1% of the ingested alpha-CD is absorbed intact and is excreted via the kidneys. No (14)C-alpha-CD was found in the feces. It is concluded from the data that ingested (14)C-alpha-CD is not digested in the small intestine of rats but is fermented completely by the intestinal microbiota to absorbable short-chain fatty acids. Therefore, the metabolism of alpha-CD resembles closely that of resistant starch or other fermentable dietary fibers.

[Subtotal bilateral adrenalectomy preserving adrenocortical function]

This study analyzed the frequency of recurrence and postoperative adrenocortical function in 16 patients who had been operated on by bilateral subtotal adrenalectomy since 1995. Bilateral pheochromocytoma was found in 13 patients, bilateral adrenal metastases in 2 patients, and bilateral micronodular adrenocortical hyperplasia with primary aldosteronism in 1 patient. An endoscopic approach was performed in four patients. The remaining 12 patients were operated on by an open approach. In ten patients, unilateral subtotal adrenalectomy with contralateral total adrenalectomy (synchronous or metachronous) was performed. Six patients underwent bilateral subtotal adrenalectomy. In all patients, a total of residual adrenal tissue of at least 1/3 of a normal adrenal gland was left in situ. 15 patients were successfully weaned from exogenous steroid substitution. During a mean follow-up period of 24 months, no recurrences were observed. Three patients died without local recurrence. The present study provided evidence for the safety and benefit of subtotal bilateral adrenalectomy, which could guarantee sufficient adrenocortical function in adrenal remnant volume of more than one-third of one adrenal gland even after dividing the main adrenal vein. At our institution, particularly in patients with inherited pheochromocytoma, subtotal adrenalectomy has become a common surgical strategy.

Effect of oral D-tagatose on liver volume and hepatic glycogen accumulation in healthy male volunteers

Standard toxicity tests with high levels of D-tagatose showed a reversible enlargement of the liver in Sprague-Dawley rats without increase of liver enzymes. The present study tests the hypotheses that partial substitution of dietary sucrose by D-tagatose for 28 days increases the volume of human liver and the concentration of liver glycogen. Twelve healthy, male volunteers were studied in a double-blind crossover study with ingestion of D-tagatose (3x15 g daily) and placebo (sucrose, 3x15 g daily) for periods of 28 days each. Liver volume and glycogen concentration have been determined by magnetic resonance (MR) imaging and spectroscopy, which were accompanied by routine medical examinations. MR examinations before and after the treatments revealed no effects (P>0.05) of treatment, period, or subject for changes in liver volume or glycogen concentration. A steady increase of liver volumes, independent of the D-tagatose or placebo intake, has been observed over the study in parallel with a slight increase in body weight. The treatment with D-tagatose was not associated with clinically relevant changes of the examined clinico-chemical and hematological parameters, including liver enzymes and uric acid.

Gastrointestinal tolerance of gamma-cyclodextrin in humans

The gastrointestinal tolerance of gamma-cyclodextrin (gamma-CD) was examined in 24 healthy human volunteers. In a double-blind, placebo-controlled, randomized cross-over study, single acute doses of 8 g maltodextrin (placebo) or 8 g gamma-CD (test) were consumed as a mid-morning snack after addition to 100 g yogurt. Gastrointestinal symptoms as well as frequency and consistency of stools were recorded before and after lunch at between 3-4 and 7-8 h after intake respectively. The perception of the symptoms was rated on a subjective scale ranging from 1 ('more than normal') to 3 ('exceptionally more than normal'). Following consumption of maltodextrin, five subjects reported a total of 12 symptoms of which seven, two and three were rated as having grade 1, 2 and 3, respectively. Following consumption of gamma-CD, five subjects reported six symptoms all of which were graded as 1. Two subjects reported flatulence, which is a frequent consequence of the consumption of malabsorbed carbohydrates, after placebo and test treatment. The incidence of individual and combined side-effects as well as the number and consistency of faeces passed was not significantly different between placebo and test treatment. It is concluded that single doses of 8 g gamma-CD and maltodextrin are tolerated equally well. This is in keeping with a good digestibility of gamma-CD by salivary and pancreatic amylase.

L-Sorbose but not D-tagatose induces hemolysis of dog erythrocytes in vitro

Previous investigations have demonstrated that L-sorbose induces hemolysis of dog erythrocytes. This effect is probably the consequence of an ATP depletion of the red blood cells subsequent to inhibition of hexokinase, and thus the glycolytic pathway, by sorbose 1-phosphate. In the present study, the susceptibility of dog erythrocytes to D-tagatose, a stereoisomer of L-sorbose, was examined. Washed dog erythrocytes were suspended in Hanks' balanced salt solution (HBSS, containing 5.6 mM glucose) with or without the addition of 0.6, 6, and 60 mM L-sorbose or D-tagatose, or in HBSS with total glucose concentrations of 5.6, 6 and 60 mM D-glucose. After incubation for 24 h at 34 degrees C, the suspensions were centrifuged, and the percentage of hemolysis was determined by measuring the hemoglobin in the sediment and the supernatant. The amount of hemoglobin released in the medium did not differ significantly between the control (HBSS) and the test incubations with glucose or D-tagatose supplementation. In contrast, the addition of 6 and 60 mM L-sorbose resulted in significant hemolysis. At the low dose (0.6 mM), L-sorbose did not have an adverse effect. It is concluded that D-tagatose, unlike L-sorbose, does not have a hemolytic effect on canine erythrocytes.

Effect of D-tagatose on liver weight and glycogen content of rats

D-tagatose is an incompletely absorbed ketohexose (stereoisomer of D-fructose) which has potential as an energy-reduced alternative sweetener. In an earlier 90-day toxicity study, rats fed diets with 10, 15 and 20% D-tagatose exhibited increased liver weights, but no histopathological alterations. To determine whether there might be any toxicological relevance to this effect, three studies were conducted in male, adult Sprague-Dawley rats. In the first study, four groups received Purina diet (group A), Purina diet with 20% D-tagatose (group B), SDS diet (group C), or SDS diet with 20% D-tagatose (group D). For groups A and B, the 28-day treatment period was followed by a 14-day recovery period (Purina diet). Food remained available to all animals until the time of sacrifice. Groups of 10 rats were killed on days 14 (groups A and B), 28 (groups A-D), and 42 (groups A and B). Body weights, as well as weights of wet and lyophilized livers, were determined. The lyophilized livers collected on day 28 from groups A and B were analyzed for protein, total lipid, glycogen, DNA, and residual moisture. By day 14, relative wet liver weights had increased by 23% in group B. On day 28, the increase was 38% in group B and 44% in group D. At the end of the recovery period, the increase had diminished to 14% in group B. On day 28, liver glycogen content (in %) was significantly increased, and liver protein, lipid, and DNA contents were significantly decreased in group B compared to group A. Total amounts per liver of protein, total lipid, glycogen, and DNA were significantly increased. In the second study, four groups of 20 rats each received SDS diet with 0, 5, 10, and 20% D-tagatose for 29-31 days. The food was available until the time of sacrifice. At termination, plasma was obtained from 10 rats/group for clinicochemical analyses. Five rats/group were subjected to whole-body perfusion, followed by processing of livers for qualitative and quantitative electron microscopic examination. Livers of 6 rats/group were analyzed for acyl-CoA oxidase and laurate 12-hydroxylase (cytochrome P450 4A1) activity, DNA synthesis (Ki-67 index), and number of nuclei per unit area of tissue. Liver weights were significantly increased in linear relation to the D-tagatose intake. Plasma transaminases (but not glutamyl transferase and alkaline phosphatase) were increased in the high-dose group. Except for glycogen accumulation, no ultrastructural changes were seen on electron microscopic examination of livers of the control and high-dose groups. Morphometric analysis confirmed the increase of glycogen and the absence of alterations of endoplasmatic reticulum, mitochondria, and Golgi apparatus. The Ki-67 index did not differ between the groups. A dose-related decrease of the number of nuclei per unit area signified some hepatocellular hypertrophy. Acyl-CoA oxidase and CYP4A1 activity were significantly increased in the mid- and high-dose groups, but these increases were small and not accompanied by electron-microscopic evidence of peroxisome proliferation. In the third study, four groups received SDS diet (groups A and C) or SDS diet with 5% D-tagatose (groups B and D). All animals were killed on day 28. Groups A and B were fasted for 24 h before sacrifice; groups C and D had food available until sacrifice. Liver weights and liver composition were measured as in Study 1. Relative wet and dry liver weights were increased in response to the treatment in rats killed under the fed condition, but not in rats killed under the fasted condition. The livers of the treated rats (group D) had an increased glycogen content in comparison to the controls (group C). Taken together, these results demonstrate that D-tagatose at dietary levels of 5-20% increases liver glycogen deposition and relative liver weights in nonfasting rats. In fasted rats the 5% dose level is the no-effect level. (ABSTRACT TRUNCATED)

Characteristics and significance of D-tagatose-induced liver enlargement in rats: An interpretative review

This review addresses the issue of asymptomatic liver enlargement in rats. It was necessitated by the observation of significantly increased liver weights in rats fed diets with 10 to 20% D-tagatose, a potential new bulk sweetener, for between 28 and 90 days. Increases of liver size without accompanying histopathological changes or impairment of organ function have been observed in rats in response to the ingestion of various xenobiotic compounds (including some food additives), changes of dietary composition (e.g. , high doses of fructose and sucrose), metabolic aberrations (e.g., diabetes), as well as normal pregnancy and lactation. The underlying mechanism(s) are not yet understood in detail but peroxisome proliferation, microsomal enzyme induction, increased storage of glycogen or lipids, and hyperfunction due to an excessive workload are well-established causes of hepatomegaly in rats. In D-tagatose- and fructose-fed rats, a treatment-related increase of hepatic glycogen storage was identified as a likely cause of the liver enlargement. Dietary levels of 5% and about 15-20% were determined as no-effect levels (NOEL) for D-tagatose- and fructose-induced liver enlargement, respectively. At doses above the NOEL, D-tagatose is about four times more efficient than fructose in inducing liver enlargement. On the other hand, the estimated intake of D-tagatose from its intended uses in food is about four times lower than the actual fructose intake. Consequently, a similar safety margin would apply for both sugars. Considering the similarity of the liver effects in rats of fructose, a safe food ingredient, and D-tagatose, the absence of histopathological changes in rats fed a diet with 20% D-tagatose for 90 days, and the absence of adverse long-term consequences of glycogen-induced liver enlargement in rats, it is concluded that the observed liver enlargement in D-tagatose-fed rats has no relevance for the assessment of human safety of this substance.

Embryotoxicity and teratogenicity study with gamma-cyclodextrin in rats

The embryotoxicity/teratogenicity of gamma-cyclodextrin (gamma-CD) was examined in Wistar Crl:(WI)WU BR rats. gamma-CD was fed at dietary concentrations of 0, 1.5, 5, 10, and 20% to groups of 25 pregnant female rats from day 0 to 21 of gestation. A comparison group received a diet with 20% lactose. The additions to the diet of gamma-CD and lactose were made at the expense of pregelatinized potato starch. Body weight and food and water intake were recorded during the treatment period. The rats were killed on day 21 and examined for standard parameters of reproductive performance. The fetuses were examined for signs of toxic and teratogenic effects. Generally, gamma-CD was well tolerated and no deaths occurred in any group. Weight gain and food consumption were similar in all groups during gestation, except for a slightly reduced food intake in the 20% gamma-CD group from day 0 to 16. Water intake was similar in all gamma-CD groups; in the lactose group, it was significantly higher than in the control group. Reproductive performance was not affected by the gamma-CD treatment. Examination of the fetuses for external, visceral, and skeletal alterations did not reveal any fetotoxic, embryotoxic, or teratogenic effects of gamma-CD. In conclusion, no adverse effects were observed at gamma-CD intakes of up to about 20% of the diet (approximately 11 g/kg body wt/day).

Subchronic (13-week) oral toxicity study of gamma-cyclodextrin in dogs

The oral toxicity of gamma-cyclodextrin (gamma-CD) was examined in a 13-week feeding study in which four groups of four male and four female Beagle dogs received gamma-CD in the diet at concentrations of 0 (control), 5, 10, or 20%. No treatment-related changes were noted in behavior or appearance of the dogs and no mortalities occurred. Transient diarrhea occurred in some dogs of the 5 and 10% dose groups and in all dogs of the 20% dose group. However, all dogs remained in good health and gained weight. During the last 6 weeks of the study, the males of the 20% dose group gained less weight, but body weights were not significantly reduced in comparison to controls. Food intakes and food efficiencies were comparable among all groups. No treatment-related differences were observed with respect to ophthalmoscopic examinations, hematological parameters, clinicochemical analyses of the plasma, and semiquantitative urine analyses. Only the urinary pH was slightly below control levels in males of the 20% dose group. No abnormalities were seen at necropsy that could be attributed to treatment. The organ weight data revealed some cecal enlargement in the 10 and 20% dose groups. Relative ovary weights were significantly increased in the 10 and 20% groups but this was probably a result of an unusually low ovary weight in the controls. An increase of relative liver weights in males of the 10 and 20% dose groups also was considered to lack toxicological relevance because it was not associated with changes in plasma liver enzyme levels or histopathological changes. On microscopic examination, no treatment-related effects were observed in any of the various organs and tissues. In conclusion, transient diarrhea, cecal enlargement, and a slightly increased acidity of the urine were the only treatment-related effects reported. These changes are well-known physiological responses to the presence of increased amounts of undigested, fermentable carbohydrates in the lower gut. At the high applied intakes an incomplete digestion of gamma-CD and/or a partial inhibition of pancreatic amylase by gamma-CD could account for these effects. It is concluded that daily gamma-CD consumption of up to 20% in the diet (approximately 7.7 g/kg body wt in male and 8.3 g/kg body wt in female dogs) was tolerated without any toxic effects.

Subchronic oral toxicity studies with gamma-cyclodextrin in rats

The toxicity of gamma-cyclodextrin (gamma-CD), a cyclic polymer of eight alpha-1,4-linked glucopyranosyl units with potential applications as a food ingredient, was examined in a 2-week pilot study followed by a 13-week oral toxicity study in Wistar rats. In the 2-week study, the test substance was administered to groups of 5 male rats at dietary levels of 0, 5, 10, 15, and 20%. In the 13-week study, groups of 20 rats/sex received diets with 0, 1.5, 5, or 20% gamma-CD. In each study, a comparison group receiving a diet with 20% lactose also was included. The 13-week study also included satellite groups of 10 rats/sex for the control and 20% gamma-CD groups. These satellite groups were kept on a standard, cereal-based rodent diet for a 4-week recovery period after termination of the treatment period. Parameters measured during the two studies were clinical signs, body weights, food and water intake, clinicochemical parameters, organ weights, and gross observation at necropsy. In the 13-week study, ophthalmoscopic and hematological examinations, urine and feces analyses, and histopathological examination of standard organs and tissues were conducted. There were no treatment-related mortalities in either study. Soft stools and, in the 13-week study, infrequent occurrences of diarrhea were noted in the lactose group at the beginning of treatment. Among the gamma-CD groups, soft stools occurred in only a few animals of the high-dose groups (>/=10% gamma-CD) during the first few days of treatment. Mean body weights tended to be slightly reduced in males of the 20% gamma-CD and 20% lactose groups. However, food efficiency was not affected by treatment except in the 13-week study in males of the 20% gamma-CD group during the first week of treatment. The hematological examinations and the semiquantitative urinalyses (conducted in the 13-week study) and the clinicochemical investigations (both studies) did not reveal any changes that could be attributed to gamma-CD treatment. Except for a slight cecal enlargement, which is commonly observed in rodents upon ingestion of incompletely absorbed carbohydrates, organ weights did not exhibit relevant changes as a result of gamma-CD treatment. On histopathological examination (13-week study), no treatment-related abnormalities were found. In conclusion, the ingestion of gamma-CD for 13 weeks at dietary levels of up to 20% (corresponding to intakes of 11.4 and 12.7 g/kg body wt/day for male and female rats, respectively) was well tolerated and did not produce any signs of toxicity.

Subchronic intravenous toxicity studies with gamma-cyclodextrin in rats

The toxicity of gamma-cyclodextrin (gamma-CD), a cyclic polymer of 8 alpha-1,4-linked glucopyranosyl units with potential applications in food and pharmaceutical preparations, was examined in two toxicity studies in rats with intravenous administration of gamma-CD for 1 and 3 months, respectively. Each study comprised four groups of 15 rats/sex each. In the 1-month study, gamma-CD was administered to the four groups at daily doses of 0 (controls), 200, 630, or 2000 mg/kg body wt, respectively. In the 3-month study, dose levels of 0, 60, 120, and 600 mg/kg body wt were tested. gamma-CD was administered by injection of an aqueous solution in the tail vein. At the end of the treatment period, 10 rats/sex/group were killed. The remaining 5 rats continued the study without treatment (recovery period) for 4 weeks (1-month study) or 5 weeks (3-month study). The treatment was generally well tolerated and there were no mortalities in either study. Mean body weights tended to be slightly reduced during the first and second week in the groups receiving gamma-CD at doses of >/=600 mg/kg body wt. Thereafter, body weights did not differ between treated groups and controls. Examination of standard hematological parameters at the end of the treatment period revealed decreased erythrocyte counts, hemoglobin, hematocrit values, and thrombocyte counts in both studies at gamma-CD doses of >/=600 mg/kg body wt. Concomitantly, the relative weight of the spleen was increased. In the high-dose group of the 1-month study, hemoglobin was detected in the urine. It is likely that a direct interaction of the injected gamma-CD with blood cells accounts for these effects. Examination of standard clinicochemical parameters at the end of the treatment period did not reveal any changes that would point to the liver as a target organ for gamma-CD toxicity. This was confirmed by the absence of histopathological changes in the liver. The only noteworthy observation was an increase of serum urea in the high-dose group (either sex) of the 1-month study and in males of the high-dose group of the 3-month study, suggesting a slight impairment of the renal function. On histopathological examination, reabsorptive vacuolation was seen in the renal tubular epithelium of some rats receiving gamma-CD at doses of 630 or 600 mg/kg body wt in the 1- and 3-month study, respectively. In the high-dose group of the 1-month study, all animals exhibited this morphological effect. However, degenerative changes were not observed in the kidneys, and the vacuolation was fully reversible on cessation of the treatment. The occurrence of absorptive vacuolation was attributed to the presence of gamma-CD in urine (parenterally administered gamma-CD is excreted unchanged in the urine). Simple or focal hyperplasia of the urinary bladder epithelium was observed in some animals of the high-dose group of the 3-month study. This hyperplasia was not seen at the end of the recovery period and, therefore, was considered to be a reactive response to the treatment. The most prominent morphological effect was an accumulation of phagocytosing alveolar macrophages (histiocytosis) in the lungs of rats receiving gamma-CD at a dose of >/=600 mg/kg body wt. This effect was associated with an increase of relative lung weights. However, degenerative changes (fibrosis) were not seen, and at the end of the recovery period only some small residual changes were noted in the lungs of a few animals. In conclusion, daily intravenous gamma-CD doses of 120-200 mg/kg body wt were tolerated without adverse effects. The changes observed at higher dose levels (>/=600-630 mg/kg body wt) were reversible on cessation of the treatment and are considered to be biochemical responses, without toxicological relevance, to the presence of transiently high concentrations of gamma-CD in the circulating blood.

Disposition of [14C]gamma-cyclodextrin in germ-free and conventional rats

The absorption, disposition, metabolism, and excretion of 14C-labeled gamma-cyclodextrin ([14C]gamma-CD) was examined in four separate experiments with Wistar rats. In experiment 1, [14C]gamma-CD (25 microCi, 600 mg/kg body wt) was administered intravenously to four male and four female conventional rats. In experiment 2, [14C]gamma-CD (25 microCi, 1000 mg/kg body wt) was given by gavage to four male and four female germ-free rats. In experiments 3 and 4, [14C]gamma-CD (25 and 100 microCi, respectively, 1000 mg/kg body wt) was given to four male and four female conventional rats by gavage. In all experiments, 14C was measured in respiratory CO2, urine, feces, contents of the gastrointestinal tract, blood, main organs, and residual carcass. The chemical identity of the 14C-labeled compounds was examined by HPLC in urine (experiments 1-4), blood (experiments 1 and 4), and samples of intestinal contents (experiments 3 and 4). Recovered 14C was expressed as a percentage of the administered dose. Total recovery of 14C varied between about 90% (experiments 3 and 4) and 100% (experiments 1 and 2). Experiment 1 showed that about 90% of intravenously administered gamma-CD is excreted in urine within 24 h. During the first 2 h after dosing, plasma 14C levels decreased rapidly (t1/2, 15-20 min). The remaining 10% of the dose was probably excreted into the gastrointestinal tract with bile and saliva. In addition, some [14C]gamma-CD may have been degraded by plasma and tissue amylases. Since glucose is the common product of systemic hydrolysis and intestinal digestion, it is not possible to quantitate the relative flux of [14C]gamma-CD through these two pathways. Upon oral administration of [14C]gamma-CD to germ-free rats (experiment 2), about 66% of the label was expired as CO2 within 24 h. The rate of 14C exhalation reached a maximum at 90 min after dosing and then declined steadily. In the urine, and in the contents of the cecum and colon collected at 24 h, [14C]gamma-CD was not found (except for a trace in the cecum of females). In conventional rats (experiments 3 and 4), a similar, fast appearance of respiratory 14CO2 was observed. There was no delayed formation of 14CO2 due to incomplete digestion and subsequent microbial fermentation in the cecum and colon. In pooled urine collected at 4 h after dosing, a small amount of unchanged [14C]gamma-CD was detected (experiment 4). From this result, it was estimated that less than 0.02% of ingested intact gamma-CD was absorbed and excreted with the urine. It is concluded from the data that ingested [14C]gamma-CD is rapidly and essentially completely digested in the small intestine to absorbable [14C]glucose. The absorption of intact [14C]gamma-CD by passive diffusion is very low (<0.02%). Therefore, the metabolism of gamma-CD resembles closely that of starch or linear dextrins.

Embryotoxicity and teratogenicity study with gamma-cyclodextrin in rabbits

In a standard embryotoxicity/teratogenicity study, gamma-cyclodextrin (gamma-CD) was administered to groups of 16, artificially inseminated New Zealand White rabbits at dietary concentrations of 0, 5, 10, or 20%. A comparison group received a diet containing 20% lactose. Treatment started on day 0 of gestation and ended on day 29 when the animals were killed. Except for the occurrence of transient diarrhea in 2 and 3 rabbits of the 10 and 20% gamma-CD groups, respectively, in the first few days, the treatment was well tolerated. A reduced food intake in the 20% gamma-CD group during the first week of treatment resulted in a reduced weight gain during this period. However, after week 1 there were no differences in weight gains between the groups, and at termination of the study body weights were similar in all groups. Even at the highest dose level, which corresponds to an intake of 5-7 g/kg body wt/day, no signs of maternal toxicity were observed. Reproductive performance was not affected by the treatment. Uterine weight, placental weight, fetal weight, number of fetuses, sex ratio, number of implantation sites, resorptions, and corpora lutea did not differ among the groups. Visceral and skeletal examinations of the fetuses did not reveal any malformations, anomalies, or variations that could be attributed to treatment. It was concluded that dietary gamma-CD is well tolerated by pregnant rabbits, has no adverse effect on reproductive performance, and is not embryotoxic, fetotoxic, or teratogenic at dietary concentrations of up to 20%.

Tolerance to subchronic, high-dose ingestion of erythritol in human volunteers

Erythritol is a sugar alcohol (polyol) which is absorbed from the small intestine in substantial amounts, not metabolized in the human body, and therefore excreted in the urine. Erythritol holds promise as a low-calorie sugar substitute. Human tolerance to repeated oral doses of erythritol was examined in a double-blind, two-way crossover study in 12 healthy, male volunteers. The participants consumed erythritol and, for comparison, sucrose for a duration of 7 days each. The daily dose of the test compounds ingested was 0.3 g/kg on Day 1, 0.6 g/kg on Day 2, and 1.0 g/kg on subsequent days. The daily dose was consumed under supervision in five portions, i.e., with the three main meals, a midmorning snack, and during the afternoon. The test compounds were incorporated into yoghurt, cookies, soft drinks, and chocolate. On each treatment day, body weight and blood pressure were measured and the participants were interviewed about side effects and their perception of stool and urine production. During the last 96 hr of each treatment period, urine was collected at 3-hr intervals during the day and for a 9-hr interval overnight for analysis of erythritol and different urinary parameters. On Days 3 to 7 of each treatment period, the participants were institutionalized. Body weights and blood pressure remained stable during the entire study. Signs of gastrointestinal intolerance were not seen and stool frequency and appearance were not different between the two treatments. The intake of liquids, which were provided ad libitum, was generally rather high (32.8 g/kg body wt/day on average) but not different between erythritol and sucrose consumption. Urine output also was high during both treatment periods. About 78% of ingested erythritol was excreted in the urine which led to a higher urinary osmolality but did not influence the 24-hr output of creatinine, citrate, urea, or electrolytes (Na+, K+, Cl-, Pi). The excretion of calcium was slightly higher during the erythritol test period but in absolute terms this increase was small. The urinary excretions of albumin, beta 2-microglobulin, and N-acetyl-glucosaminidase were slightly elevated during the erythritol test period but they were still well within the physiological range. None of the observed urinary changes became more pronounced with increasing duration of the erythritol treatment. In conclusion, the results of the present study demonstrate that the repeated ingestion of erythritol at daily doses of 1 g/kg body wt was well tolerated by humans.

Disposition of 14C-erythritol in germfree and conventional rats

The metabolism and disposition of U-14C-erythritol was examined in four groups of three male and three female, nonfasted rats each. The rats of groups A and D were germfree; the rats of groups B and C were kept under conventional conditions. The rats of group B received an erythritol-supplemented diet for 3 weeks prior to the experiment (adapted rats). The rats of groups A, C, and D were kept on an ordinary diet which was sterile for groups A and D (not adapted rats). On the day of the experiment, each rat was dosed with U-14C-erythritol by gavage (5 microCi/kg body wt; sp act 50 microCi/g erythritol). The radiochemical purity of the erythritol was 96.43% for groups A-C. Group D, which was attached to the study after evaluation of the results of groups A-C, received a more purified erythritol with a radiochemical purity of 99.46% because the data of group A pointed to a possible interference by a 14C-labeled impurity in the commercial 14C-erythritol. After dosing, respiratory CO2 and urine were collected from each rat at regular intervals for 24 hr. At termination, feces were also collected. The animals were killed and intestinal contents, organs, tissues, and the remaining carcass processed for determination of 14C-14C was excreted rapidly in the urine of all groups (range of groups A-D: 47.3-60.6% of the administered dose within the first 4 hr). Total 24-hr urinary excretion varied between 67.0% (group B) and 81.4% (group D). HPLC analysis of the urine showed that more than 96% of the eluted radiolabel represented erythritol. Conventional, adapted rats expired more 14CO2 than conventional, unadapted rats [10.9% (B) vs 6.7% (C)]. Germfree rats expired much less 14CO2 [0.8% (A) and 0.3% (D)]. In germfree rats, 14CO2 expiration started shortly after dosing, reaching half of the 24-hr excretion after about 2.5 hr. In conventional rats 14CO2 expiration started with a delay of about 2 hr reaching half the 24-hr excretion after 4-6 hr. The excretion of 14C with feces was similar in all groups (8.3% on average of all rats). Slightly more 14C was retained in the intestinal contents of germfree than conventional rats (1.9 vs 0.5%). The body retention was higher in conventional than in germfree rats (3.4 vs 2.0%). In group D, body retention was lowest (1.6%). The total recovery of 14C was similar in all groups (95.6%, average of all rats). It is concluded that ingested erythritol is efficiently absorbed mainly from the small intestine, is not metabolized to a relevant extent in the body, and is excreted unchanged in the urine. The fraction of erythritol not absorbed is fermented by the gut microflora to intermediate products which are largely absorbed and metabolized. The data support a proposed physiological energy value for erythritol of about 0.5 kcal/g.

Chronic toxicity and carcinogenicity study of erythritol in rats

The potential toxicity and carcinogenicity of erythritol, a low-calorie sugar substitute, were examined in Wistar Crl:(WI) WU BR rats. Groups of 50 rats of each sex consumed diets with 0, 2, 5, or 10% erythritol, or 10% mannitol, for a period of 104-107 weeks. To each of these main groups, two satellite groups of 20 males each were attached for interim kills after 52 and 78 weeks of treatment. At start of the study, the rats were 5-6 weeks old. The average intakes of erythritol in the 2, 5, and 10% groups were 0.9, 2.2, and 4.6 g/kg body wt/day for males and 1.0, 2.6, and 5.4 g/kg body wt/day for females, respectively. Mannitol intakes were 4.4 and 5.2 g/kg body wt/day in males and females, respectively. All treatments were well tolerated without diarrhea or other side effects. Body weights were significantly below control levels during most of the study in males of the 5% erythritol group and in males and females of the 10% erythritol and 10% mannitol groups. Survival of the animals was not adversely affected by the treatments. Hematological and clinicochemical examinations did not reveal noticeable changes which could be attributed to treatment. Analysis of urine samples collected during five 48-hr periods, from rats of the satellite groups in Weeks 26, 42, 50, and 78 and from rats of the main groups in Week 102, showed that about 60% of ingested erythritol was excreted unchanged. The urine volumes increased with increasing dietary erythritol levels. In line with previous observations on other polyols, erythritol and mannitol ingestion led to an increased excretion of urinary calcium and citrate. The urinary excretions of sodium, potassium, phosphate, N-acetylglucosaminidase (NAG), gamma-glutamyltransferase (GGT), low-molecular-weight protein (LMP), and total protein (TP) were slightly elevated in the 10% erythritol group. Increased GGT and NAG excretions also were seen occasionally at the 5% dose. Significantly increased relative cecum weights were seen in rats of either sex in the 10% mannitol and, somewhat less pronounced, 10% erythritol groups. Some cecal enlargement also was seen in the 5% erythritol group. The relative weight of the kidneys was highest in the 10% erythritol group, the difference from controls reaching statistical significance at interim kills (males) and termination (females). Except for more frequent pelvic nephrocalcinosis in female rats of all erythritol dose groups, the histopathological examinations did not reveal any nonneoplastic, preneoplastic, or neoplastic changes that could be attributed to the ingestion of erythritol. In male and female rats of the 10% mannitol group, pelvic nephrocalcinosis, which in females was associated occasionally with pelvic hyperplasia, was the only remarkable finding. The incidence and progression of nephrosis, which is commonly seen in aging rats of this strain, were not influenced by the treatments. In the absence of morphological alterations in the kidneys or other signs of nephrotoxicity, the increased excretions of NAG, GGT, LMP, and TP are regarded as innocuous, functional sequelae of the renal elimination of erythritol. In conclusion, the toxicological profile of erythritol in rats resembles that of other polyols in several respects. Except for nephrocalcinosis, which is commonly seen in polyol-fed rats, no other treatment-related, morphological changes were observed in the kidneys. Evidence for a tumor-inducing or tumor-promoting effect of erythritol was not seen.

Two-generation reproduction study of erythritol in rats

Erythritol was fed at dietary concentrations of 0, 2.5, 5, or 10% to Crl:(WI) WU BR rats of both sexes through two successive generations (F0 and F1). Twenty-four rats of each sex were mated in each group. For each generation one litter was reared until the pups were 21 days old. In the 10% erythritol group, food consumption among F0-males and -females was initially significantly reduced until the animals adapted to the erythritol diet during the first week of the study. Thereafter, food intake was higher than in controls. A consistently increased food intake also was seen in F1-males and-females of this dose group. This effect was considered to result from the caloric dilution of the food by erythritol, which has a low physiological energy value. The lower body weight and weight gain of the F0-animals of the 10% erythritol group were attributed to the initially reduced food consumption and occurrence of transient diarrhea until the animals had adapted to the erythritol intake. In the F1-animals of the 10% erythritol group, which were adapted to the treatment from weaning, the rate of body weight gain did not differ from controls. The F1-males and -females of this dose group did, however, have a reduced body weight from weaning, which was attributed to a reduced energy intake among the corresponding F0-dams during Weeks 2 and 3 of lactation. This effect was not seen in the F2-generation. It is concluded that under the conditions of this experiment, the intake of erythritol had no adverse effect on fertility and reproductive performance of parent rats or on the development of their progeny. Gross necropsy and microscopic examination of the parenteral reproductive organs also did not reveal treatment-related changes.

Embryotoxicity and teratogenicity study with erythritol in rats

The embryotoxicity/teratogenicity of erythritol, a low-calorie polyol sugar substitute, was examined in Wistar Crl:(WI) WU BR rats. Erythritol was fed at dietary concentrations of 0, 2.5, 5, and 10% to groups of 32 female rats from Day 0 to 21 of gestation. The treatment was generally well tolerated and no mortality occurred in any group. Weight gain during gestation, food consumption, and food efficiency were similar in all groups except for a significantly reduced weight gain in the 10% erythritol group in Week 2 of gestation. Reproductive performance was not affected by the treatment but the fertility index was generally rather low (69% in both control and high-dose group). Examination of the fetuses for external, visceral, and skeletal alterations did not reveal any fetotoxic, embryotoxic, or teratogenic effects. The slightly lower maternal body weight in the high-dose group was interpreted as a trivial result of the consumption of a low-calorie test substance in high amounts. In conclusion, no adverse effects were observed at erythritol doses of up to about 6.6 g/kg body wt/day, i.e., the highest dose tested.

Subchronic oral toxicity studies with erythritol in mice and rats

Erythritol is a sugar alcohol (polyol) with potential applications as a low-calorie, bulk sweetener. Ingested erythritol is efficiently absorbed and excreted unchanged via the urine since it is not metabolized systemically by the animal or human body. Erythritol was administered to four groups of 10 male and 10 female Swiss CD-1 mice and four groups of 15 male Wistar Crl:(WI) WU BR rats at dietary levels of 0, 5, 10, or 20% for 90 days. A fifth group of rats received a diet containing 20% erythritol on a time-restricted basis (6 hr/day), and a sixth group received a diet containing 20% mannitol for comparison. There were no treatment-related mortalities in either mice or rats. Soft stools and occasional diarrhea were observed in rats fed diets with 20% erythritol or mannitol but not in mice. Body weights were slightly yet significantly reduced in rats fed 20% erythritol or mannitol and in male mice of the 20% dose group. Erythritol intake in the high-dose group was approximately 12 g/kg body wt in rats and 44 and 45 g/kg body wt in male and female mice, respectively. Hematological and clinicochemical examinations of blood and plasma did not reveal any treatment-related effects. Urine output increased with increasing erythritol dose. In male and female mice of the 20% erythritol group, the creatinine-normalized urinary excretion of protein, K-glutamyltransferase (GGT), and electrolytes (Na+, K+, Ca2+, Pi, citrate) was significantly increased while urinary N-acetylglucosaminidase (NAG) remained unchanged. At the 10% level, significantly increased urinary protein (both sexes) and GGT (males only) excretion were seen. In rats, the creatinine-normalized urinary excretion of GGT, NAG, and some electrolytes (Na+, K+, and Ca2+) was increased in some erythritol groups but a clear dose-response relationship was evident only for calcium. On termination of the study, cecal enlargement was seen in rats of the 10 and 20% dose groups and in mice of the 20% dose group. Increased relative and absolute kidney weights were observed in both sexes of mice in the 20% erythritol group, in male mice of the 5 and 10% groups, and in rats of the 10 and 20% erythritol groups. Histopathological examination did not reveal any treatment-related abnormalities in either mice or rats. In conclusion, the ingestion of erythritol for 90 days at dietary levels of up to 20% did not produce signs of toxicity in mice or rats. In particular, the morphological integrity of the kidneys was not adversely affected by the treatment in either species. The increases in urinary excretion of protein, GGT, NAG, and electrolytes were considered to result from extensive osmotic diuresis and a potential overload of the renal excretory system at the high dose levels employed.

Subchronic oral toxicity study with regular and enzymatically depolymerized sodium carboxymethylcellulose in rats

Enzymatically depolymerized sodium carboxymethylcellulose (CMC-ENZ) is a new functional food ingredient which has a lower molecular weight and viscosity than regular sodium carboxymethylcellulose (CMC). Both compounds are known not to be absorbed to a significant extent, and the human safety of CMC as a thickening agent and stabilizer in food is well established. In the present study, the subchronic oral toxicity of CMC-ENZ was examined and compared with that of CMC in Wistar rats. Seven groups of 20 rats/sex were fed diets with 0 (controls), 2.5, 5 and 10% CMC and 2.5, 5 and 10% CMC-ENZ for a 3-month period. There was only one death that was unrelated to the treatment. Water intake, urine production and urinary sodium excretion increased with increasing doses of CMC and CMC-ENZ due to their sodium content of about 7-8%. The treatment-related occurrence of diarrhoea and caecal enlargement in the mid- and high-dose groups, a slight increase of plasma alkaline phosphatase, and increased urinary calcium and citrate excretions were considered to be generic effects that typically are observed in rodent studies with low digestible carbohydrates. The increased occurrence of nephrocalcinosis and hyperplasia of the urothelial epithelium in some of the treated groups was interpreted as an indirect consequence of a more alkaline urine coupled with an increased calcium excretion. As the frequency and severity of all these changes did not differ between corresponding CMC and CMC-ENZ dose groups, it is concluded that the two products have a similar toxicological profile.

Metabolic disposition in rats of regular and enzymatically depolymerized sodium carboxymethylcellulose

Partially enzyme-hydrolysed sodium carboxymethylcellulose (CMC-ENZ), which holds promise as a new, functional food ingredient, is obtained from sodium carboxymethylcellulose (CMC) by enzymatic hydrolysis with a cellulase preparation from Trichoderma longibrachiatum. In the safety evaluation of CMC-ENZ, a comparative disposition study on 14C-labelled CMC and CMC-ENZ was conducted in conventionally kept rats. The 14C label was in the two C atoms of the carboxymethyl group. Two groups of four male and four female rats each were fed diets with 5% unlabelled CMC or CMC-ENZ for a 2-wk adaptation period. A single oral dose of 14C-CMC or 14C-CMC-ENZ solution was then given by gavage (500 mg/kg body weight). Respiratory CO2, urine and faeces were collected at regular intervals, and after 120 hr organs, tissues and the carcass were sampled as well. For both experimental groups, total mean recovery of 14C was 98%, about 95% of the label being excreted with the faeces, 2% or less in the urine, 1% or less with CO2 and a small fraction being retained in the body (CMC, 0.58%; CMC-ENZ, 0.75%). Tissue retention of 14C was highest in the liver of rats of both experimental groups. Only about 49 and 65% of the faecal 14C was extracted with water in the 14C-CMC and 14C-CMC-ENZ dosed rats, respectively. Gel permeation chromatography (GPC) of the dosing solutions and the faecal extracts revealed that CMC is depolymerized during intestinal passage whereas CMC-ENZ is excreted nearly unchanged. Consequently, the molecular weight distribution of the 14C-CMC and 14C-CMC-ENZ faecal excretion products was similar. It is concluded that there is no toxicologically relevant difference between the disposition of CMC and CMC-ENZ.

Intake of intense sweeteners in Germany

The dietary intake of aspartame, cyclamate, and saccharin was evaluated in Germany (FRG) in 1988/89. In the first part of the study the sweetener intake was evaluated in a representative sample of the population. Complete 24-h records of the amount and type of all foods and drinks consumed were obtained from 2,291 individuals. The total daily intake was calculated for each person from the sweetener content of each product and was expressed in mg/kg body weight (bw). 35.9% of the participants ingested one or more sweeteners on the examination day. Cyclamate and saccharin were the prominent sweeteners because aspartame was at that time permitted only under special regulatory exemption, and products containing acesulfame were not yet available. For users of intense sweeteners the mean intakes of aspartame, cyclamate, and saccharin were 0.15, 2.62, and 0.250 mg/kg bw/day, respectively. At the 90th percentile of intake, i.e., for the heavy consumer, the ingestion of cyclamate and saccharin was about 2.5 times higher. Persons who adhered to a diet (diabetes, weight control) did not ingest sweeteners in substantially higher amounts. Tabletop sweeteners and beverages were the most important sources of sweeteners, and they contributed more than 80% of the total intake. Consumption of sweeteners in excess of the Acceptable Daily Intake (ADI) was rarely observed (saccharin: one person, cyclamate: 16 persons). In the second part of the study, the sweetener intake was further evaluated during a 7-day period in those subjects who in the 1-day study ingested any of the sweeteners in excess of 75% of the ADI. Complete 7-day food records were available from 40 out of the 41 subjects who fulfilled this criterium. In this selected subgroup in which 19 subjects were less than 19 years old, the mean daily intakes of aspartame, cyclamate, and saccharin were 0.13, 4.53, and 0.42 mg/kg body weight (bw), respectively. These levels correspond to 0.33, 41 and 17% of the corresponding ADI values. No subject exceeded the ADI of aspartame or saccharin on any day of the study. For cyclamate, the mean daily intake over the 7-day period exceeded the ADI in 4 subjects. The results indicate that at the time of the study the then valid German sweetener regulation protected the consumer adequately, and that the sweetener intake was in 99.8% of all examined persons within recommended limits.

Chronic stimulation-induced changes of myosin light chains at the mRNA and protein levels in rat fast-twitch muscle

Transitions in the expression of the myosin light chains (LC) were investigated in fast-twitch muscles of the rat during chronic (10 h/day), low-frequency (10 Hz) stimulation. Changes were followed at the mRNA level by Northern blot analysis and in vitro translation, as well as at the protein level by electrophoresis under denaturing and nondenaturing conditions. In vivo synthesis of the light chains was assessed by measuring the incorporation of intramuscularly injected [35S]methionine. Chronic stimulation induced a transition in the isomyosin pattern with an increase of FM3, a concomitant decrease in FM1 and, after longer stimulation periods, the appearance of low concentrations of the slow isomyosin. These changes were accompanied by an elevated LC1f/LC3f ratio and increases in the amounts of both the LC1sb and, to a lesser degree, LC2s proteins. Alterations in the amounts of specific mRNAs were the same whether determined by Northern blot analysis or by in vitro translation of total RNA preparations from the same muscles. Generally, the changes in the relative concentrations of fast and slow light-chain proteins agreed with the changes detected at the mRNA level and the alterations in protein synthesis detected with the use of an in vivo labeling assay. An exception was the elevated tissue content of LC2s where no changes were detectable in the concentration of its mRNA as determined by in vitro translation or in vivo synthesis. The increase in LC2s protein may, therefore, have been due to reduced degradation. In addition, the decrease in LC3f was more pronounced at the protein level than at the mRNA level. This might indicate an increased turnover of LC3f or the existence of additional post-transcriptional regulations of LC3f expression.

Altered expression of myosin light-chain isoforms in chronically stimulated fast-twitch muscle of the rat

Fast-twitch tibialis anterior muscle of the rat was chronically stimulated for periods of 18 days, 28 days and 56 days. Changes in the myosin light-chain (LC) pattern consisted in an increase in LC1f, concomitant with a decrease in LC3f. In contrast to previous findings in chronically stimulated fast-twitch tibialis anterior muscle of the rabbit, no substantial increases occurred in the slow myosin light-chain isoforms. In vivo labeling using [35S]methionine incorporation revealed differences in relative turnover between the fast myosin light chains. The relative turnover of the fast myosin light chains appeared to increase in normal muscle in the order LC2f less than LC1f less than LC3f. As judged from [35S]methionine incorporation, the changes in light-chain tissue content mainly resulted from altered synthesis rates. However, in the case of LC3f the decrease in protein content could not only be explained by a reduced synthesis, but, additionally, appeared to be due to enhanced degradation. Parvalbumin, which was included in the present study, was also found to decrease in the stimulated muscle. However, its decrease appeared to result primarily from reduced synthesis.

Three fast myosin heavy chains in adult rat skeletal muscle

A new fast myosin heavy chain isoform was electrophoretically detected in adult rat skeletal muscles. It was present at high levels in diaphragm and, therefore, designated as MHCIId. Appreciable amounts of MHCIId were detected in tongue musculature, the extraocular muscles, and in the deep red portions of various fast muscles. Its concentration in fast-twitch muscle was greatly increased by chronic stimulation.

Urinary glycolate measured by use of (S)-2-hydroxy-acid oxidase

Glycolate can be determined in urine by using (S)-2-hydroxy-acid oxidase (EC 1.1.3.15; formerly called "glycolate oxidase"), either immobilized in a continuous-flow system or in a semiautomated procedure for the centrifugal analyzer. In the presence of peroxidase (EC 1.11.1.7), the hydrogen peroxide formed from glycolate is detected by use of a peroxide indicator reaction. Before the analysis, urine must be treated with charcoal to remove reducing substances such as ascorbic acid, which interfere with the assay by decreasing the color of the indicator reaction. Lactate also interferes with the determination of glycolate because it also is a substrate for this oxidase; thus a correction has to be made for the lactate content of urine. The system with (S)-2-hydroxy-acid oxidase immobilized to the inner surface of nylon tubing is accurate, precise, and sensitive but unsuitable for routine use because, even immobilized, the oxidase is unstable and can only be used for 12 days. We have used the semiautomated assay routinely: it has a mean analytical recovery of 96% (SD 4.2%), a within-batch CV less than 2%, and a between-batch CV less than 5%. The normal reference interval for urinary excretion of glycolate so measured is 0.13 to 1.31 mmol per day (n = 55).

Urinary glycolate measured by use of (S)-2-hydroxy-acid oxidase

Glycolate can be determined in urine by using (S)-2-hydroxy-acid oxidase (EC 1.1.3.15; formerly called "glycolate oxidase"), either immobilized in a continuous-flow system or in a semiautomated procedure for the centrifugal analyzer. In the presence of peroxidase (EC 1.11.1.7), the hydrogen peroxide formed from glycolate is detected by use of a peroxide indicator reaction. Before the analysis, urine must be treated with charcoal to remove reducing substances such as ascorbic acid, which interfere with the assay by decreasing the color of the indicator reaction. Lactate also interferes with the determination of glycolate because it also is a substrate for this oxidase; thus a correction has to be made for the lactate content of urine. The system with (S)-2-hydroxy-acid oxidase immobilized to the inner surface of nylon tubing is accurate, precise, and sensitive but unsuitable for routine use because, even immobilized, the oxidase is unstable and can only be used for 12 days. We have used the semiautomated assay routinely: it has a mean analytical recovery of 96% (SD 4.2%), a within-batch CV less than 2%, and a between-batch CV less than 5%. The normal reference interval for urinary excretion of glycolate so measured is 0.13 to 1.31 mmol per day (n = 55).

Enzootic and epizootic adrenal medullary proliferative disease of rats: influence of dietary factors which affect calcium absorption

Adrenal medullary hyperplasia and neoplasia occur both enzootically and epizootically in untreated laboratory rats. The lesions are typically chromaffin-negative and are found incidentally in animals that have died from unrelated causes or have been killed at the end of long-term toxicity/carcinogenicity tests. Urinary excretion of catecholamines is not usually increased. Environmental, particularly dietary, factors are seemingly much more important than genetic ones as determinants of the incidence of proliferative lesions. Recent observations of enhancement of adrenal medullary proliferative disease in rats by the feeding, in high dietary concentration, of certain polyols (sorbitol, mannitol, xylitol, lactitol), or of lactose, suggested that increased absorption of calcium from the gastrointestinal tract may be a risk factor. This evidence is reported and discussed in the light of other evidence linking disturbed calcium homeostasis with adrenal medullary function in the rat. In man, adrenal medullary proliferative disease is relatively rare and there is no evidence of any relation between the hypercalcaemia associated with hyperparathyroidism and increased risk of phaeochromocytoma. Adrenal medullary proliferative disease in rats is usually seen against a background of multiple endocrine neoplasia, with the pituitary gland, the pancreatic islets and the thyroid C-cells being most commonly affected in addition to the adrenal medulla. A parallel between this situation and Sipple's disease in humans has previously been suggested. We now stress the possible importance of three factors as determinants of enzootic and epizootic adrenal medullary proliferative disease in rats: excessive food intake, excessive dietary levels of calcium and phosphate and excessive intake of other food components, such as vitamin D and poorly absorbable carbohydrates, which predispose to increased calcium absorption.

Some functional characteristics of adrenal medullary tumors in aged male Wistar rats

Neither analysis of the urinary catecholamine metabolites vanillymandelic acid and 4-hydroxy-3-methoxyphenylglycol nor blood pressure measurements allowed the detection of adrenal medullary tumors or hyperplasia in 115 aged male Wistar rats (70 rats, 24 months of age and 45 rats, 30 months of age). Histochemical examination of the adrenal glands demonstrated that the 55 hyperplastic and 25 neoplastic lesions of the medulla usually had little or no chromaffinity. Chromaffinity was found comparable to normal medulla in only three tumors examined histochemically. Of these tumors, two were partially and one completely chromaffin-positive, but all three were small and did not result in elevated blood pressure or catecholamine metabolite excretion values. These observations indicate that excessive catecholamine synthesis and release is not a feature of adrenomedullary tumors and hyperplasia occurring spontaneously in aged male Wistar rats.

[Prevalence of serological hepatitis A and B markers in Bavarian blood donors (author's transl)]

Sera from 1966 Bavarian blood donors were investigated by radioimmunoassay for serological markers of past hepatitis A and B infections. The prevalence of hepatitis A antibody increased with age and was higher in the urban than in rural populations. More than 80% of persons above 40 years of age had antibody whereas only few young adults showed previous exposure to hepatitis a virus. 20 of 1093 random persons (1.8%) were HBsAg positive at first blood donation. In all age groups anti-HBc was the best marker for previous hepatitis B exposure. There was no correlation between the frequency of hepatitis A and B markers.