Glucagon in the Treatment of Paget's Disease of Bone

Glucagon given by intravenous infusion at a dosage of 0·2 to 0·8 mg/hour to four patients with Paget''s disease of bone resulted in a dramatic fall in plasma alkaline phosphatase. This was associated with a fall in 24-hour urinary calcium and in total urinary hydroxyproline excretion and a marked relief of bone pain.Glucagon may induce these changes by three possible mechanisms: (1) by stimulating release of calcitonin; (2) by a direct action of the hormone on bone; and (3) by stimulation of certain bone pyrophosphatases, thus altering the local mechanisms controlling the rate of bone formation and resorption.     

Use of Glucagon in the Treatment of Pancreatitis

Four patients with pancreatic disease received glucagon intravenously. In two a definite decrease in the volume of pancreatic exocrine secretion was shown, and in one of these pancreatic juice protein and bicarbonate levels also fell. Two patients with acute pancreatitis had pronounced relief of epigastric pain associated with falls in plasma amylase after intravenous glucagon.Several mechanisms could account for the possible beneficial effect of glucagon in pancreatitis, and further studies of its use in this disease are justified.     

Role of biotin-containing membranes and nuclear distribution in differentiating human endometrial cells

Human Ishikawa endometrial cells form domes when confluent monolayers are stimulated with fresh fetal bovine serum. Extensive structural and biochemical changes have been detected during the approximately 30 h differentiation period. The earliest detectable change involves the formation of multinucleated structures and the appearance of “granules” that stain for biotin within those structures. Nuclei become associated with each other and are ultimately enclosed within a biotin-containing membrane. Aggregated membrane-sheathed nuclei and the cells containing them begin to elevate from the dish as biotin staining becomes apparent in apical membranes. The elevated structures are called predomes and consist of one or more very large cells containing the sheathed nuclei. Apical membranes of these unusual cells extend far out into the medium in structures that resemble endometrial pinopods. A lumen under the elevated cells fills with transcytosed fluid. As differentiation proceeds, highly concentrated chromatin material that was flattened against apical and lateral membranes of the predome cells begins to disperse. Small mononuclear cells evolve from larger predome cells. Apical membranes of predome and dome cells continue to stain for biotin. Gel electrophoresis of SDS-solubilized biotin-containing membranes, followed by Western blot analysis using avidin-linked peroxidase, resulted in three stained bands with molecular weights similar to those of the mitochondrial carboxylases: propionyl carboxylase, methylmalonyl carboxylase, and pyruvate carboxylase. J. Cell. Biochem. 71:400–415, 1998. © 1998 Wiley-Liss, Inc.     

Cell-cycle arrest in TrkA-expressing NIH3T3 cells involves nitric oxide synthase

We have examined nerve growth factor (NGF)-triggered signaling in two NIH3T3 cell lines exogenously expressing the NGF receptor, TrkA. TRK1 cells cease to proliferate and extend long processes in response to NGF, while E25 cells continue to proliferate in the presence of NGF. These two cell lines express similar levels of TrkA and respond to NGF with rapid elevation of mitogen-activated protein kinase (MAPK) activity. MAPK activation is slightly more sustained for E25 cells than for TRK1 cells, although sustained activation of MAPK has been suggested to cause cell-cycle arrest. As judged by NADPH-diaphorase staining, nitric oxide synthase (NOS) activity is increased in TRK1 cells upon exposure to NGF. In contrast, diaphorase staining in E25 cells is unaffected by NGF treatment. Immunocytochemistry shows that levels of the brain NOS (bNOS) isoform are increased in TRK1, but not E25, cells exposed to NGF. Furthermore, Western blots show that NGF elevated cyclin-dependent kinase inhibitor, p21(WAF1), in TRK1 cells only. NGF-induced p21(WAF1) expression, cell-cycle arrest and process extension are abolished by N-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NOS. The inactive enantiomer, D-NAME, did not inhibit these responses. Furthermore, even though E25 cells do not respond to NGF or nitric oxide donors, they do undergo a morphological change in response to NGF plus a nitric oxide donor. Therefore, NOS and p21(WAF1) are induced only in the TrkA-expressing NIH3T3 cell line that undergoes cell-cycle arrest and morphological changes in response to NGF. These results demonstrate that sustained activation of MAPK is not the sole determining factor for NGF-induced cell-cycle arrest and implicate NO in the cascade of events leading to NGF-induced morphological changes and cell-cycle arrest.     

5'-to-3' exoribonuclease activity in bacteria: role of RNase J1 in rRNA maturation and 5' stability of mRNA

Although the primary mechanism of eukaryotic messenger RNA decay is exoribonucleolytic degradation in the 5'-to-3' orientation, it has been widely accepted that Bacteria can only degrade RNAs with the opposite polarity, i.e. 3' to 5'. Here we show that maturation of the 5' side of Bacillus subtilis 16S ribosomal RNA occurs via a 5'-to-3' exonucleolytic pathway, catalyzed by the widely distributed essential ribonuclease RNase J1. The presence of a 5'-to-3' exoribonuclease activity in B. subtilis suggested an explanation for the phenomenon whereby mRNAs in this organism are stabilized for great distances downstream of "roadblocks" such as stalled ribosomes or stable secondary structures, whereas upstream sequences are never detected. We show that a 30S ribosomal subunit bound to a Shine Dalgarno-like element (Stab-SD) in the cryIIIA mRNA blocks exonucleolytic progression of RNase J1, accounting for the stabilizing effect of this element in vivo.     

Occurrence of a Highly Heat-Sensitive Spore Subpopulation of Bacillus coagulans STCC 4522 and Its Conversion to a More Heat-Stable Form

The profile of the survival curves, at different heating temperatures, of B. coagulans STCC 4522 sporulated at 52(deg)C has been studied, focusing on the early moments of treatment. A highly heat-sensitive spore subpopulation that includes more than 90% of the total spore population has been found. This heat-sensitive spore fraction was inactivated after 2 s of treatment at 111(deg)C. Its heat resistance was as much as 200-fold lower than that of the heat-resistant spore fraction (D(inf111(deg)C) of 0.01 min for the heat-sensitive spore fraction compared with D(inf111(deg)C) of 2 min for the heat-resistant fraction). The shape of the survival curve at 108.5(deg)C was modified after a sublethal heat shock at 80(deg)C for 3.5 h, resulting in a straight-line survival curve. The temperature of treatment also influenced the shape of the survival curves. The conversion of the highly heat-sensitive spore subpopulation to a more heat-stable form is discussed.     

Selective inhibitors of tumor progression loci-2 (Tpl2) kinase with potent inhibition of TNF-α production in human whole blood

Tpl2 (cot/MAP3K8) is an upstream kinase of MEK in the ERK pathway. It plays an important role in Tumor Necrosis Factor-α (TNF-α) production and signaling. We have discovered that 8-halo-4-(3-chloro-4-fluoro-phenylamino)-6-[(1H-[1,2,3]triazol-4-ylmethyl)-amino]-quinoline-3-carbonitriles (4) are potent inhibitors of this enzyme. In order to improve the inhibition of TNF-α production in LPS-stimulated human blood, a series of analogs with a variety of substitutions around the triazole moiety were studied. We found that a cyclic amine group appended to the triazole ring could considerably enhance potency, aqueous solubility, and cell membrane permeability. Optimization of these cyclic amine groups led to the identification of 8-chloro-4-(3-chloro-4-fluorophenylamino)-6-((1-(1-ethylpiperidin-4-yl)-1H-1,2,3-triazol-4-yl)methylamino)quinoline-3-carbonitrile (34). In a LPS-stimulated rat inflammation model, compound 34 showed good efficacy in inhibiting TNF-α production.     

Oligonucleotide Conjugates: Alteration of the Pharmacokinetic Properties of Antisense Agents

Abstract

Cholic acid, cholesterol, several polyamines and polyethylene glycols were conjugated to antisense oligonucleotides targeted to human or murine intercellular adhesion molecule-1 (ICAM-1) mRNA to study their effects on cellular absorption.