Elemental diets in treatment of acute Crohn's disease.

Twenty-seven patients with 32 acute exacerbations of Crohn''s disease were treated for four weeks with an elemental diet. At the end of treatment 29 of the exacerbations had remitted both clinically and biochemically. After six months six patients had relapsed. These findings suggest that the elemental diet is effective in treating acute Crohn''s disease, but the reasons are not clear. The diet may be effective because it provides nutritional support, is hypoallergenic, acts as a medical bypass from the affected area, or alters bowel flora. The patient''s general wellbeing is improved by the supply of adequate energy and essential foodstuffs in a form easily available without further digestion and given in a safe, simple, non-toxic way.     

Environmental phenotypic variation of Scenedesmus dimorphus in high-rate algae ponds and its relationship to wastewater treatment and biomass production

During the course of operating high-rate algae ponds (HRAP) for wastewater treatment and protein production, changes were found in the two main algae species. The observed changes were interpreted to be a reflection of the operation regime and loading combined with environmental conditions. To verify that these changes were phenotypic and not genetic, experiments were conducted on Scenedesmus dimorphus growing in miniponds (110 L) as well as in the laboratory. The results showed that the changes in S. dimorphus were external and due to the changes in the loading and operating conditions of the ponds adjusted to changing environmental conditions. It was found that wastewater treatment efficiency and algal yield are also correlated with the S. dimorphus type.     

Regulatory Properties of the ADP-Glucose Pyrophosphorylase of the Blue-Green Bacterium Synechococcus 6301

ADP-glucose was found to be the primary sugar nucleotide used for glycogen synthesis by Synechococcus 6301. ADP-glucose pyrophosphorylase was partially purified 12-fold from this blue-green bacterium. The enzyme was activated 8- to 25-fold by glycerate 3-phosphate. Fructose 6-phosphate, fructose 1,6-bisphosphate, 5'-adenylate, and adenosine diphosphate activated the enzyme, but less than glycerate 3-phosphate. The enzyme was inhibited by inorganic phosphate. The I(0.5) of phosphate was 0.072 mm, and in the presence of 2 mm glycerate 3-phosphate, increased to 1.8 mm. The substrate saturation curves for glucose 1-phosphate and ATP were hyperbolic in both the presence and absence of glycerate 3-phosphate or phosphate. The saturation curve for MgCl(2) was sigmoidal; 2 mm glycerate 3-phosphate decreased the sigmoidicity from a Hill slope n value of 5.6 to 2.8, and increased the MgCl(2) optimum from 3 mm to 6 to 7 mm.     

Importance of the flux of phosphate across the inner membrane of kidney mitochondria for the activation of glutaminase and the transport of glutamine

The effect of mersalyl, an inhibitor of phosphate transport across the inner mitochondrial membrane, was investigated on the uncoupled respiration of pig kidney mitochondria in the presence of glutamine as substrate and on the activity of the phosphate-dependent glutaminase in the intact organelles. In addition, the submitochondrial location of the enzyme was reinvestigated.

1. (1) It was found that mersalyl completely inhibits uncoupled respiration of the mitochondria in the presence of glutamine as substrate, whereas respiration with glutamate was not affected. The same amount of mersalyl which inhibits coupled oxidation of glutamine also inhibits coupled oxidation of glutamate and some other substrates.

2. (2) Mersalyl strongly inhibited the activation of glutaminase in intact mitochondria only in the presence of inhibitors of electron transport or of an uncoupler. The addition of a detergent prevented or fully released the inhibition. The effect of mersalyl was observed even when the mitochondria were pre-incubated with phosphate or incubated in the phosphate-free medium. If mersalyl and carbonyl cyanide m-chlorophenylhydrazone (CCCP) were added 3 min after pre-incubation with phosphate the same intramitochondrial concentration of the anion as in control experiments was found, whereas the activity of glutaminase was severely inhibited. These findings suggest that the activation of the enzyme by phosphate in intact nonenergized mitochondria occurs only if the activator moves across the inner mitochondrial membrane.

3. (3) Mersalyl (plus CCCP) markedly decreased [¹⁴C]glutamine- and [³²P]-phosphate-permeable mitochondrial spaces. A close correlation between the decrease of phosphate and glutamine permeable spaces and the inhibition of glutaminase activity was found.

4. (4) If the activation energy of the enzyme was determined with frozen mitochondrial preparations, a discontinuity or break in the Arrhenius plot was observed, whereas the presence of a detergent completely abolished the break. Digitonin or ultrasonic treatment of the mitochondria followed by separation of the membrane and the soluble fraction revealed that glutaminase is a membrane-bound enzyme.

On the basis of these findings it is concluded that there is an association between the transport of phosphate on one side and the transport of glutamine and glutaminase activity on the other. It is possible that the movement of phosphate across the membrane activates the enzyme which facilitates diffusion of glutamine down a concentration gradient. However, the existence of a specific glutamine-phosphate carrier is not ruled out.     

Synthesis and chemical behaviour of D-glucosyl esters of glutamic acid having the side-chain carboxyl group involved in the glycosidic linkage.

Simultaneous and stepwise deprotection of the fully benzylated D-glucosyl esters of 1-benzyl N-benzyloxycarbonyl- and N-tert-butyloxycarbonyl-L-glutamic acid (1 and 5, respectively) have been examined. Catalytic hydrogenation of 1 led to intramolecular aminolysis to give pyroglutamic acid and D-glucose, but similar treatment in the presence of trifluoroacetic acid afforded both anomers of 1-O-(L-gamma-glutamyl)-D-glucopyranose, which were characterized as trifluoroacetates (2alpha and 2beta) and converted into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(acetyl)-L-glutam-5-oyl]-D-glucopyranose (4) which was also prepared by a definitive method. Hydrogenolysis of 5 gave both anomers of 1-O-[N-(tert-butyloxycarbonyl)-L-gamma-glutamyl]-D-glucopyranose (6), which, upon treatment with trifluoroacetic acid at - 10 degrees, afforded 2alpha and 2beta, respectively. The structure of 6beta was established by its conversion into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-beta-D-glucopyranose (7beta), whereas similar treatment of 6alpha gave a mixture of 1,3,4,6-tetra-O-acetyl-2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (9) and 7alpha. A 1 leads to 2 acyl migration occurred during esterification of the aglycon carboxyl group of 6alpha with diazomethane to give 2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (8).     

The effect of temperature and crowding on midgut amylolytic activity in Tenebrio molitor adults

The effect of two constant temperatures (23°C and 28°C), mixed group (5 + 5), and isolation on the midgut amylolytic activity during adult development of Tenebrio molitor has been investigated in vitro. Higher temperatures (28°C) and mixed groups stimulate the rate of midgut amylolytic activity. After attaining the maximal level, the amylolytic activity shows fluctuations. The possible role of hormones and primer pheromones in the control of the midgut amylolytic activity in T. molitor adults is discussed.     

A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli

Summary Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135–800 m) between which clustered groups of globuli (4–14 urn in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125–500 Å in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.Dedicated to Professor Berta Scharrer on the occasion of her 70th birthdayWith the technical assistance of Mr. P.A. MilliquetThe author wishes to thank Mr. Bauer and Mr. Fryder (Nestec SA, La Tour de Peilz) for the use of the Cambridge Stereoscan electron microscope and Dr. T. Jalanti (C.M.E., Lausanne) for his help with the use of the X-ray microanalyser     

Diaminobutyric acid: A tool for discriminating between carrier-mediated and non-carrier-mediated release of GABA from synaptosomes?

The carrier-mediated transport of GABA in rat brain synaptosomes was strongly and permanently inhibited byl-2,4-diaminobutyric acid (DAB). In order to discriminate between carrier-mediated and non-carrier-mediated release of [³H]GABA, synaptosomes prelabeled with 0.5 M [³H]GABA in the presence of 100 M DAB, or with 0.2 M [³H]GABA without DAB, were superfused in conditions stimulating the release of [³H]GABA. Only the release elicited by unlabeled GABA or DAB (by homo- and heteroexchange, respectively) was strongly inhibited in DAB-pretreated synaptosomes. The spontaneous release and the release induced by 56 mM KCl in the presence of CaCl₂, by the ionophore A23187, by ouabain, by lack of K⁺, or by purified black widow spider toxin were unaffected or only barely decreased in DAB-treated synaptosomes, and therefore do not seem to be mediated by the DAB-blocked GABA carrier.