Effects of bestatin on myelopoietic stem cells in normal and cyclophosphamide-treated mice

Summary The effect of bestatin on hematopoietic parameters and bone marrow progenitor activity (colony-forming unit — granulocyte/macrophage: CFU-GM) was examined in normal and myelosuppressed C₅₇BL/6 mice. CFU-GM frequency and absolute number were determined with a limiting dilution analysis of bone marrow cells in soft agar using recombinant murine colony-stimulating factor — granulocyte/macrophage. We report that bestatin increased splenic, bone marrow, and peripheral blood cellularity and the number of CFU-GM over a dose range from 2.5 mg/kg through 100 mg/kg following i.p., i.v., or oral administration. The greatest myeloid stimulation was observed following multiple injections of bestatin. Bestatin also increased the recovery from cyclophosphamide-induced myelodepression as measured by these parameters. The hematopoietic properties of bestatin following oral administration is of potential importance for clinical application.By acceptance of this article, the publisher or recipient acknowledges the right of the U. S. Government to retain a nonexclusive, royalty-free license in and to any copyright covering the article. This research was supported by the DHHS, under contract no. N01-23910 with Program Resources Inc. The contents of this publication do not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U. S. Government.     

Production of Types A and B Spores of Clostridium botulinum by the Biphasic Method: Effect on Spore Population, Radiation Resistance, and Toxigenicity

Spores of three strains each of type A and type B Clostridium botulinum were produced both by a biphasic (solid medium overlaid with an aqueous phase) and by a "conventional" (deep broth culture) procedure. Sporogenesis by the biphasic system was more rapid, convenient, and economical, and yielded as many or more heat-resistant (80 C, 10 min) spores per milliliter as by the conventional technique. Of several aqueous phases [thiamine-hydrochloride, yeast extract, (NH(4))(2)SO(4)] tested with strain 62A, the highest spore colony counts were obtained with 2.0% (NH(4))(2)SO(4). The six strains formed maximum spore numbers in 5 to 6 days of incubation. Spores produced by the two methods had essentially equal radiation resistances (D and lag values), and their subcultures gave similar toxin titers (LD(50) values).     

Radioimmunoassay specific for amino (N) and carboxyl (C) terminal portion of parathyroid hormone.

A radioimmunoassay specific for the amino (N) terminal portion of the parathyroid hormone (PTH) molecule (N-PTH radioimmunoassay) has been developed by iodinating synthetic 1-34bovine PTH (1-34bPTH) and using commercially available bPTH antiserum. A radioimmunoassay specific for the carboxyl (C) terminal (C-PTH radioimmunoassay) has been carried out by adding enough amount of 1-34bPTH to the PTH radioimmunoassay system. The data obtained from N- and C-PTH radioimmunoassay were compared with those obtained from the PTH radioimmunoassay. It was observed that plasma levels of N-PTH, indicating biologically active PTH, were only one 8th to 32th to those of PTH and those of C-PTH were almost equal to those of PTH. These data corresponded well with those reported previously by using the antiserum specific for each terminal of the PTH molecule from the other laboratory. The half life of plasma N-PTH and C-PTH determined following the removal of parathyroid adenoma was less than 10 min and about 45 min respectively. These data indicate that the N-PTH radioimmunoassay can be done by iodinating 1-34bPTH and using commercially available antiserum.     

Radiation Sterilization of Prototype Military Foods. III. Pork Loin

Ten lots of pork loin, packed in cans, were inoculated with approximately 10(6)Clostridium botulinum spores per can. Each lot was seeded with a different strain; five type A and five type B strains were used. The pack comprised 5,690 cans, including controls, and contained about 10(9) spores per dose. The cans were irradiated with Co(60) in the range of 0 to 5.0 Mrad (0.5 Mrad increments) at 5 to 25 C, incubated for 6 months at 30 C, and examined for swelling, toxicity, and recoverable C. botulinum. The minimal experimental sterilizing dose (ESD) based on nonswollen, nontoxic, but nonsterile end points was 2.5 < ESD 相似文献   

Production of Nucleic Acid-Related Substances by Fermentative Processes. XXVIII. Accumulation of 5′ Inosinic Acid by a Manganese-Insensitive Mutant of Brevibacterium ammoniagenes

A manganese-insensitive mutant, KY 13105, of Brevibacterium ammoniagenes which accumulates considerable amounts of 5' inosinic acid (IMP) in the presence of 100 to 1,000 mug of Mn(2+) per liter was obtained from an IMP-producing mutant of a manganese-sensitive strain, KY 13102. The effects of Mn(2+) at 0 to 30 mug/liter on IMP accumulation by KY 13105 were similar to those by KY 13102. However, the accumulation of IMP by KY 13105 was not affected by 100 to 1,000 mug of Mn(2+) per liter, showing a clear difference from KY 13102. The accumulation of IMP by KY 13105 was always accompanied by cellular morphological changes irrespective of Mn(2+) concentration. In the presence of Mn(2+), factors which affect IMP accumulation by KY 13105 were examined. Most of the nutrients tested stimulated IMP accumulation at a relatively low concentration (2 g/liter). Iron, calcium, and zinc were found to be essential for IMP accumulation and were independent of Mn(2+). Biotin regulated the growth but not the accumulation of IMP. Under limited or surplus amounts of Mn(2+), the dynamics of IMP fermentation were followed. Under both conditions, the fermentations proceeded in a similar way. The morphological changes were found to be closely related to IMP accumulation.     

Examination of exchange assay for glucocorticoid receptor

We examined a method for the measurement of total, activated and non-activated glucocorticoid receptors using sodium-p-hydroxymercuribenzoate (PHMB) and dithiothereitol (DTT) developed by Banerji and Kalimi (1981). Since the concentration of PHMB required for dissociation of the ligand from the receptors varied with the concentration of protein in the reaction mixture and the rate of reassociation of the ligand to the ligand-liberated receptors was sensitive to the concentration of PHMB used, it was necessary to find the minimum concentration of PHMB which was required for complete dissociation of the ligand. When the optimum concentration of PHMB was selected based on the concentration of protein in the cytosol, almost 100% exchange was attained in the non-heated dexamethasone (Dex)-receptor complexes by this method. However when Dex-receptor complexes were heated at 25 degrees C for 30 min, the amount of 3H-Dex reassociated with the glucocorticoid receptors dropped to 60% of that of the non-heated ones. DEAE-cellulose chromatography of the heated sample revealed that approx. 40% of the bound receptors were activated (eluted with 0.05 M KCl) during the heating period. After DEAE cellulose column chromatography of the exchanged 3H-Dex receptor, complexes reassociated with 3H-Dex were observed only in the fraction of unactivated receptor complexes (eluted with 0.2 M KCl). Furthermore, the fraction eluted with 0.05 M KCl in the DEAE cellulose chromatography of liver cytosol bound to unlabelled Dex did not exchange significantly with 3H-Dex with the method used in the present study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial and complete adenine phosphoribosyltransferase deficiency associated with 2,8-dihydroxyadenine urolithiasis: kinetic and immunochemical properties of APRT

We have studied adenine phosphoribosyltransferase (APRT) in the hemolysates from the families of 2,8-dihydroxyadenine urolithiasis associated with partial deficiency of APRT (the Japanese type) and complete deficiency of APRT (the null type). The APRT in the control subjects was found to be heat-stable at the physiological concentration of phosphoribosylpyrophosphate (PRPP), which was close to the value of its Km for PRPP. The APRT in the Japanese type showed 10 times higher Km values for PRPP and needed a comparably increased level of PRPP for stability in vitro. No change in red cell PRPP was found in the Japanese type of APRT deficiency. The content of APRT enzyme protein was decreased in the hemolysates of the Japanese type, probably due to its lability at the level of PRPP present in the cells. The heterozygote of the null type also had labile enzyme molecules at the physiological PRPP concentration.     

Identification of the receptor for omega-conotoxin in brain. Probable components of the calcium channel

Recently omega-conotoxin GVIA was shown to specifically block neuronal and other calcium channels. In this work, an azidonitrobenzoyl derivative of mono-[125I]iodo-omega-conotoxin GVIA was used to identify the components of its receptor site in synaptic plasma membrane by photoaffinity labeling. Components of Mr approximately equal to 310,000, approximately equal to 230,000, and 34,000 were specifically photolabeled. The characteristics of photolabeling of these three components were consistent with those of the specific binding of omega-conotoxin GVIA to synaptic plasma membrane with respect to the effects of metal ions, conventional calcium antagonists, and an agonist (1,4-dihydropyridines, verapamil, and diltiazem, etc.), omega-conotoxins GVIIA and GVIIB. Furthermore, the distribution of these three components in subcellular fractions from rat brain as estimated by photolabeling was in good agreement with that of the specific binding of omega-conotoxin GVIA to its receptor. These findings indicate that the components of Mr approximately equal to 310,000, approximately equal to 240,000, and 34,000 are the receptor for omega-conotoxin GVIA and suggest that these components are constituents of the voltage-sensitive calcium channel in brain. No specific photolabeling was observed in the plasma membrane of human erythrocytes, probably indicating the absence of the receptor for omega-conotoxin GVIA in the membrane.     

Transport and Fixation of Inorganic Carbon during Photosynthesis in the Cells of Anabaena Grown under Ordinary Air. II. Effect of Sodium Concentration during Growth on the Induction of Active Trasport System for IC

The requirement of sodium for growth of Anabaena variabilisM3 was investigated under low (0.04%) and high (1.5 or 5%) CO₂conditions. The growth rates under both conditions were stronglyaffected by NaCl concentrations up to 0.5 mM in the medium.In the presence of 40 µM NaCl, the cells were not ableto grow under a low CO₂ condition, but were able to grow undera high CO₂ condition. The sodium requirement for growth wasdependent on pH: in the Na⁺-deficient condition, cells couldgrow at pH6.8, while no growth occurred at pH 8.2, suggestingthat the requirement of Na⁺ for growth observed in the low CO₂condition can be substituted for by a lower pH. In the presence of 20 mM NaCl at pH 7.8, ¹⁴CO₂ as well as H¹⁴CO₃^–were actively transported into the cells which had been grownin air. In contrast, the transport of both of these inorganiccarbon (IC) species was suppressed under the Na⁺-deficient condition.These results suggest that sodium is required for the stimulationof transport of IC during photosynthesis. This is one of thereasons why Na⁺ is required for the growth of Anabaena underordinary air and alkaline conditions. (Received September 27, 1986; Accepted March 26, 1987)