Transcriptional profiling suggests that secondary and primary large B-cell lymphomas of the gastrointestinal (GI) tract are blastic variants of GI marginal zone lymphoma.

The pathogenetic relationship of marginal zone B-cell lymphoma (MALT lymphoma) of the gastrointestinal (GI) tract and eventually co-existing aggressive B-cell lymphoma and primary aggressive B-cell lymphoma remains to be elucidated. The RNA of laser-microdissected cells was isolated and amplified from small and/or large cell compartments of eight MALT lymphomas (small cell lymphoma, SCL), 14 GI diffuse large B-cell lymphomas (large cell lymphoma, LCL), and ten GI B-cell lymphomas with composite small and large cell compartments (ComL) and expression analyses were performed using cDNA arrays. Hierarchical cluster analysis clearly separated SCL and LCL and the small and large cell compartments of ComL. Likewise, cluster analysis with all samples of SCL, LCL, and ComL yielded two main 'small cell' and 'large cell' branches. Furthermore, 60 genes were differentially expressed between SCL and LCL, and 82 genes between the small and large cell components of ComL; 26 genes were discriminators in both settings. Use of the profiles of ComL as training sets for class prediction resulted in 95% accuracy for the classification of SCL and LCL. Collectively, the data strongly suggest that both secondary and primary aggressive B-cell lymphomas of the GI tract are blastic marginal zone lymphomas.

Hydrogen peroxide on the surface of Europa.

Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

Functional food science and the cardiovascular system.

Cardiovascular disease has a multifactorial aetiology, as is illustrated by the existence of numerous risk indicators, many of which can be influenced by dietary means. It should be recalled, however, that only after a cause-and-effect relationship has been established between the disease and a given risk indicator (called a risk factor in that case), can modifying this factor be expected to affect disease morbidity and mortality. In this paper, effects of diet on cardiovascular risk are reviewed, with special emphasis on modification of the plasma lipoprotein profile and of hypertension. In addition, dietary influences on arterial thrombotic processes, immunological interactions, insulin resistance and hyperhomocysteinaemia are discussed. Dietary lipids are able to affect lipoprotein metabolism in a significant way, thereby modifying the risk of cardiovascular disease. However, more research is required concerning the possible interactions between the various dietary fatty acids, and between fatty acids and dietary cholesterol. In addition, more studies are needed with respect to the possible importance of the postprandial state. Although in the aetiology of hypertension the genetic component is definitely stronger than environmental factors, some benefit in terms of the development and coronary complications of atherosclerosis in hypertensive patients can be expected from fatty acids such as alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid. This particularly holds for those subjects where the hypertensive mechanism involves the formation of thromboxane A2 and/or alpha 1-adrenergic activities. However, large-scale trials are required to test this contention. Certain aspects of blood platelet function, blood coagulability, and fibrinolytic activity are associated with cardiovascular risk, but causality has been insufficiently proven. Nonetheless, well-designed intervention studies should be initiated to further evaluate such promising dietary components as the various n-3 and n-6 fatty acids and their combination, antioxidants, fibre, etc. for their effect on processes participating in arterial thrombus formation. Long-chain polyenes of the n-3 family and antioxidants can modify the activity of immunocompetent cells, but we are at an early stage of examining the role of immune function on the development of atherosclerotic plaques. Actually, there is little, if any, evidence that dietary modulation of immune system responses of cells participating in atherogenesis exerts beneficial effects. Although it seems feasible to modulate insulin sensitivity and subsequent cardiovascular risk factors by decreasing the total amount of dietary fat and increasing the proportion of polyunsaturated fatty acids, additional studies on the efficacy of specific fatty acids, dietary fibre, and low-energy diets, as well as on the mechanisms involved are required to understand the real function of these dietary components. Finally, dietary supplements containing folate and vitamins B6 and/or B12 should be tested for their potential to reduce cardiovascular risk by lowering the plasma level of homocysteine.

[Nutritional physiology of whey and whey components]. / Ernährungsphysiologische Bedeutung von Molke und Molkenbestandteilen.

Deriving from positive effects of whey drinking cures in antiquity, the Middle Ages and modern time, a review is given on nutritional significance of whey. The proteins are essential components of whey and belong to the proteins with highest biological value because of their amino acid composition. Besides, they show fundamental functional properties, which enable a varied application in foods, dietetic foods and beverages in form of different whey products (powder, protein concentrates and isolates). Whey proteins have found considerable usage in infant's nutrition as whey predominant formulas as well as whey protein hydrolysates in case of cow's milk protein intolerances. A recent field of research are biological active peptide sequences which become effective during digestion and are of importance for secretion of entero hormones as well as for immune enhancing effects. They may contribute to assess the biological value of whey proteins under enlarged points of view and to develop new application forms and areas. It is pointed to further fields of application (e.g. adipositas, gout, kidney insufficiency). Concerning the quantitatively most dominant lactose in whey, it is dealt with its importance for the healthy development of infants (adaptation to the increased lactose content of mother's milk) as well as with lactose intolerance and galactosaemia. In case of mineral salts of whey it is emphasized the high nutrient density of calcium (prophylaxis for osteoporosis), the beneficial Ca:P and Na:K proportions (antihypertensive in case of the last one), the promotion of absorption of mineral salts by lactose, and the high content of iodine. The whey is rich in B-vitamins, which contribute essentially for their satisfaction or requirement in case of a corresponding consumption. To be emphasized is the vitamin B12 in milk and whey, which is the sole source of this indispensable nutrient for blood-formation and cell division in lacto-ovo-vegetarian nutrition. In conclusion, a summarizing dietetics valuation of whey is performed.

Effect of ovariectomy on bone histology and plasma parameters of bone metabolism in nulliparous and multiparous sows.

To investigate the suitability of the pig as animal model for postmenopausal osteoporosis, effects of ovariectomy (OVX) on bone metabolism and histology were studied in two groups of sows (9 months, nulliparous or 35 months, multiparous). A standard diet of about 1.5% calcium (Ca) was fed till sacrifice at either 12 or 20 months post OVX when mineral content and histology were studied in representative bone specimens of proximal tibia, iliac crest and lumbar vertebrae. At 4, 8, 12, and 18 months post OVX, total and bone-specific alkaline phosphatase (APt, APb) calcidiol, calcitriol and parathyroid hormone (PTH) were measured in plasma. In young sows OVX did not significantly affect plasma variables except for calcitriol, which was higher at 4 months post OVX. No significant differences between OVX or control animals were observed in the variables of bone chemical and histological analyses, neither 12 nor 20 months post OVX. In multiparous sows OVX significantly increased PTH plasma concentrations at 8 months post OVX and plasma calcitriol, APt and APb at 12 months post OVX. All effects were moderate and transient. OVX did not significantly affect the variables of bone chemical and histological analyses neither 12 nor 20 months post OVX. Although undoubtedly the clinical-chemical changes observed were not accompanied by any histomorphometric signs of osteopenia/osteoporosis, it must be left to future experiments as to whether this resulted from the ample calcium supply provided. This possibility is supported by recent observations showing that porcine osteopenia could be induced by OVX in animals maintained on only 0.75% dietary calcium but not on higher (0.9%) Ca regimens.

Soybean trypsin inhibitor(s) reduce absorption of exogenous and increase loss of endogenous protein in miniature pigs.

It was the purpose of this study to define whether trypsin inhibitors impair protein digestibility via enhanced loss of exogenous or endogenous protein by quantifying those losses using the homoarginine technique, recently developed in this laboratory. Pigs fitted with permanent ileal T-cannulas were fed test meals containing homoarginine-labeled protein. The meals contained casein and increasing doses of trypsin inhibitors (Experiment 1) or alternatively either heat-treated or raw ground soybeans (Experiment 2). Following a casein meal (425 mmol nitrogen, no trypsin inhibitors), ileal protein was predominantly of endogenous rather than of exogenous origin (105 vs. 9 mmol nitrogen). Addition of isolated trypsin inhibitors (3000 mg) enhanced appearance of both endogenous and exogenous protein at the ileum (by 73 and 9 mmol nitrogen, respectively). Feeding raw instead of heat-treated soybeans in one single test meal caused a significant increase of endogenous protein from 217 +/- 42 to 263 +/- 47 mmol (mean +/- SEM) and of exogenous protein from 16 +/- 3 to 48 +/- 14 mmol. If fed continuously for 1 wk, a raw soybean diet caused endogenous protein loss to rise significantly from 221 +/- 26 to 432 +/- 85 mmol. We conclude that ingestion of food containing trypsin inhibitor affects nitrogen balance more by losses of amino acids of endogenous secreta than by losses of dietary amino acids.

Dietary sucrose but not starch promotes protein-induced differences in rates of VLDL secretion and plasma lipid concentrations in rats.

Casein instead of soybean protein in a low fat, cholesterol-free diet containing sucrose increases both lipid secretion by rat liver and plasma cholesterol concentration. Male rats were studied to determine whether dietary sucrose is a prerequisite for these protein-induced differences of lipid metabolism in vivo. After 6 wk of consuming either casein plus sucrose, soybean protein isolate plus sucrose, casein plus starch or soybean protein isolate plus starch (carbohydrate, 69 g/100 g diet; protein, 20 g/100 g diet) plasma lipids were measured. VLDL degradation was blocked by Triton WR-1339 and rates of lipid secretion were calculated from the observed linear increase in plasma levels with time. Plasma cholesterol concentrations and rates of secretion of VLDL cholesterol and triglycerides were 27, 47 and 34% higher, respectively, in animals fed casein plus sucrose compared with soybean protein plus sucrose. These differences were clearly diminished or absent when starch was the dietary carbohydrate. The data substantiate the finding that dietary sucrose but not dietary starch promotes a casein-induced increase in hepatic cholesterol secretion and thus contributes to casein-induced hypercholesterolemia in rats. On the contrary, differences of triglyceride secretion were not reflected in different plasma lipid concentrations.

Enhancement of intestinal hydrolysis of lactose by microbial beta-galactosidase (EC 3.2.1.23) of kefir.

The effect of microbial beta-galactosidase (EC 3.2.1.23) activity on intestinal lactose digestion was estimated directly by following post-prandial venous plasma galactose concentrations. To avoid superimposing effects of free galactose, as with yogurt, fresh or heat-treated suspensions of mechanically disintegrated kefir grains in kefir, containing lactose but no free galactose, were fed to ten Göttingen minipigs. Each meal contained 101.1 (SEM 0.1) mmol lactose in kefir supplemented by either native or heat-treated kefir grains corresponding to a mean beta-galactosidase activity of either 72 (SEM 8) U or zero. Feeding kefir with beta-galactosidase activity resulted in a 30% enhancement of the mean post-prandial plasma galactose peak concentration from 33 (SEM 7) to 43 (SEM 12) mumol/l (n 10), as well as in 23% greater mean areas under the galactose-response curves (8.1 (SEM 1.5) v. 6.6 (SEM 1.2) mmol/min per l) if compared with kefir with heat-treated grains. Both differences were significant (P less than 0.05; paired Wilcoxon test by ranks). There was no induction of intestinal beta-galactosidase (EC 3.2.1.108) activity or intestinal lactose-hydrolysing bacteria by lactose feeding. These results give direct evidence of an enhanced lactose digestion and absorption in native fermented milk products due to the microbial beta-galactosidase activity.

Galileo ultraviolet spectrometer experiment: initial venus and interplanetary cruise results.

The Galileo Extreme Ultraviolet Spectrometer obtained a spectrum of Venus atmospheric emissions in the 55.0- to 125.0-nanometer (nm) wavelength region. Emissions of helium (58.4 nm), ionized atomic oxygen (83.4 nm), and atomic hydrogen (121.6 nm), as well as a blended spectral feature of atomic hydrogen (Lyman-beta) and atomic oxygen (102.5 nm), were observed at 3.5-nm resolution. During the Galileo spacecraft cruise from Venus to Earth, Lyman-alpha emission from solar system atomic hydrogen (121.6 nm) was measured. The dominant source of the Lyman-alpha emission is atomic hydrogen from the interstellar medium. A model of Galileo observations at solar maximum indicates a decrease in the solar Lyman-alpha flux near the solar poles. A strong day-to-day variation also occurs with the 27-day periodicity of the rotation of the sun.

Postprandial plasma D-lactate concentrations after yogurt ingestion.

The risk of D-lactic acidosis after consumption of yogurt was investigated in seven healthy volunteers. After ingestion of yogurt containing 1.06 mmol/kg body weight, D-lactic acid postprandial plasma D-lactate concentrations increased from 0.070 +/- 0.020 to a maximum of 0.200 +/- 0.010 mmol/l within 60 min. That was half the maximum concentration after the equivalent amount of D-lactate in the form of an aqueous solution of DL-lactate. The shape of the postprandial plasma D-lactate peak was flatter, but much broader after yogurt than after the aqueous solution, the peak areas being equal. When 0.64 mmol/kg body weight D-lactate were consumed as yogurt, plasma concentrations amounted to 0.086 +/- 0.030 mmol/l. Signs of a mild, transient, compensated metabolic acidosis, which was apparent in case of the aqueous lactic acid solution did not occur in case of yogurt. It is concluded that the consumption of foods containing D-lactic acid gives no reason for concern in healthy adults.

The hypocholesterolemic effect of guar gum depends on dietary sucrose--studies in minipigs.

We examined the effect of guar gum on serum lipids if fed together with either 50.3% starch or 50.3% sucrose in a balanced diet to pigs. For this purpose, five adult hypercholesterolemic minipigs (total serum cholesterol 9.0 mmol/l) underwent three consecutive 8-week crossover (control or guar supplementation) feeding experiments (experiment I = cornstarch plus 15 g guar, experiment II = cornstarch plus 30 g guar, experiment III = sucrose plus 30 g guar per day). With the cornstarch-based diet neither 15 g nor 30 g guar gum had an influence on serum total cholesterol or triglyceride levels. Also, the cholesterol concentrations in the lipoprotein fractions did not change significantly during experiments I and II, yet total serum cholesterol concentration was about 20% lower (p less than 0.01) when guar gum was added to the sucrose diet in experiment III. In the presence of sucrose the supplementation of 30 g guar led to a significant decrease (p less than 0.05) of the cholesterol concentrations in the very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL). There was also a tendency for decreased cholesterol levels in the low-density lipoproteins (LDL) after adding 30 g guar to the sucrose diet. Thus, the study demonstrates that guar gum exerts a hypocholesterolemic effect in the presence of sucrose in the diet, but not in the case of starch consumption.

Plasma amino acids and cholesterol following consumption of dietary casein or soy protein in minipigs.

Numerous investigators have claimed that protein-induced differences in plasma cholesterol are mediated by differences in amino acid composition. We have explored whether the venous postprandial amino acid profile reflects differences in the amino acid composition of the protein consumed. Six adult Göttingen miniature pigs were fed a semisynthetic diet based on either casein or soy protein isolate. Frequent blood sampling was performed over a whole day after consumption of each diet for 6 wk. Postprandial plasma amino acid concentrations reached their maxima within the first 3 h. A group of eight protein amino acids (Met, Arg, Tyr, Val, Trp, Leu, Lys and Cys) exhibited the most marked and significant protein-dependent differences during this early postprandial phase, whereas Thr and His showed less marked differences. With one exception (Ser) all protein amino acids exhibited venous plasma concentration changes in qualitative accordance with their content in the dietary protein consumed. In quantitative terms, however, venous plasma amino acid changes were less marked than expected from the amino acid composition of the dietary proteins. We conclude that neither the considerable number of amino acids showing differences as reported herein nor the multitude of contradictory reported by others concerning single amino acids affecting serum cholesterol favor the hypothesis that one or several amino acid(s) cause protein-induced hypercholesterolemia.

Response of hormones modulating plasma cholesterol to dietary casein or soy protein in minipigs.

To elucidate the mechanism mediating the effect of dietary casein or soy protein on serum cholesterol concentrations we followed the endocrine response to the intake of these dietary proteins. The hormones analyzed were those known to modulate serum cholesterol concentration. A 7-wk crossover nutrition study was performed with six adult Göttingen minipigs consuming semisynthetic diets based on either 20 wt% casein or soy isolate. At d 42 and 49, concentrations of six hormones were determined in 22 blood samples taken over the whole day. There were no significant differences in insulin, glucagon, the insulin/glucagon ratio, hydrocortisone or triiodothyronine among dietary groups. In the late postprandial phase (5 h after the meal and later) there were significantly higher growth hormone concentrations in soy-fed animals. At all times of the day, total and free thyroxine concentrations were higher after soy feeding than after casein feeding. On average, total and free thyroxine concentrations were 34 and 26% higher with soy protein feeding than with casein feeding. Our data agree with other reports of protein-dependent changes of thyroid hormones and may explain why different dietary proteins have different effects on serum cholesterol levels in sensitive species.

Biotin supply by large bowel bacteria in minipigs: evidence from intracaecal avidin.

The influence of a change of colonic availability of biotin on biotin status was studied. This was done by inhibition of biotin absorption by intracaecal avidin infusion. Five adult minipigs with a permanent caecal 'T' cannula were fed on a semi-synthetic, biotin-deficient diet for 4 months. Following an 8-week adaptation period there were nine sequential 1-week infusion periods with or without oral lactulose or antibiotics. Avidin infusion during weeks 2, 5 and 8 amounted to 18 mg/d (13 U/mg). Plasma biotin concentrations were not changed by avidin infusions. There was a significant average 84% rise in faecal biotin excretion during the avidin periods. Urinary biotin output following avidin decreased by 21%. This is taken as evidence that biotin synthesized by colonic bacteria is available for host metabolism. A rough estimate shows that under basal conditions 1.7-17% of the metabolic allowance may be covered by this metabolic route.

Difference of plasma amino acids following casein or soy protein intake: significance for differences of serum lipid concentrations.

There were significant differences of postprandial plasma concentrations for 8 amino acids (Cys, Val, Met, Leu, Tyr, Lys, Trp, and Arg) depending on whether pigs consumed a meal containing casein or isolated soy protein. The postprandial plasma amino acid pattern conformed with the amino acid composition of the dietary protein (except for Ser). The data, however, do not allow to conclude unambiguously, whether specific amino acids are responsible for the difference of serum cholesterol following casein or soy protein intake. Significant differences between casein- and soy-fed rats were observed regarding total and free plasma thyroxine and triiodothyronine concentrations. This observation can explain the accompanying different serum cholesterol concentrations. The different thyroid hormone concentrations were not paralleled by differences in TSH levels suggesting that dietary proteins affect thyroid function at the thyroid gland.

D-lactic acid metabolism after an oral load of DL-lactate.

We have investigated in normal human volunteers the short-term and long-term metabolic consequences of the oral intake of d-lactic acid. After the consumption of 6.4 or 12.8 mmol/kg(0.75) body weight of racemic dl-lactic acid, d-lactate was eliminated from plasma with half-lives of 28.6 +/- 4.3 and 40.4 +/- 5.4 min; its maximum plasma concentrations were 0.34 +/- 0.05 and 0.45 +/- 0.06 mmol/l, respectively. Less than 2% of the administered dose of d-lactic acid was excreted in urine during the 24 hours following intake. There was only a slight, non-significant decrease in blood pH by 0.02 units, accompanied by signs of a mild, compensated metabolic acidosis. A 5 weeks chronic experiment with daily consumption of 6.4 mmol/kg(0.75) body weight dl-lactic acid in 5 volunteers did not result in the accumulation of plasma d-lactate.