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.     

Autoinhibitory Interdomain Interactions and Subfamily-specific Extensions Redefine the Catalytic Core of the Human DEAD-box Protein DDX3

DEAD-box proteins utilize ATP to bind and remodel RNA and RNA-protein complexes. All DEAD-box proteins share a conserved core that consists of two RecA-like domains. The core is flanked by subfamily-specific extensions of idiosyncratic function. The Ded1/DDX3 subfamily of DEAD-box proteins is of particular interest as members function during protein translation, are essential for viability, and are frequently altered in human malignancies. Here, we define the function of the subfamily-specific extensions of the human DEAD-box protein DDX3. We describe the crystal structure of the subfamily-specific core of wild-type DDX3 at 2.2 Å resolution, alone and in the presence of AMP or nonhydrolyzable ATP. These structures illustrate a unique interdomain interaction between the two ATPase domains in which the C-terminal domain clashes with the RNA-binding surface. Destabilizing this interaction accelerates RNA duplex unwinding, suggesting that it is present in solution and inhibitory for catalysis. We use this core fragment of DDX3 to test the function of two recurrent medulloblastoma variants of DDX3 and find that both inactivate the protein in vitro and in vivo. Taken together, these results redefine the structural and functional core of the DDX3 subfamily of DEAD-box proteins.     

Mitochondrial DNA structure and colony expansion dynamics of New Zealand fur seals (Arctocephalus forsteri) around Banks Peninsula

New Zealand fur seals are one of many pinniped species that survived the commercial sealing of the eighteenth and nineteenth centuries in dangerously low numbers. After the enforcement of a series of protection measures in the early twentieth century, New Zealand fur seals began to recover from the brink of extinction. We examined the New Zealand fur seal populations of Banks Peninsula, South Island, New Zealand using the mitochondrial DNA control region. We identified a panmictic population structure around Banks Peninsula. The most abundant haplotype in the area showed a slight significant aggregated structure. The Horseshoe Bay colony showed the least number of shared haplotypes with other colonies, suggesting a different origin of re-colonisation of this specific colony. The effective population size of the New Zealand fur seal population at Banks Peninsula was estimated at approximately 2500 individuals. The exponential population growth rate parameter for the area was 35, which corresponds to an expanding population. In general, samples from adjacent colonies shared 4.4 haplotypes while samples collected from colonies separated by between five and eight bays shared 1.9 haplotypes. The genetic data support the spill-over dynamics of colony expansion already suggested for this species. Approximate Bayesian computations analysis suggests re-colonisation of the area from two main clades identified across New Zealand with a most likely admixture coefficient of 0.41 to form the Banks Peninsula population. Approximate Bayesian computations analysis estimated a founder population size of approximately 372 breeding individuals for the area, which then rapidly increased in size with successive waves of external recruitment. The population of fur seals in the area is probably in the late phase of maturity in the colony expansion dynamic.     

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.     

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.     

Effect of hydrocarbon concentration of pasture production (<i>Brachiaria humidicola</i>) in Texistepec,Veracruz

In this study, the relationship between the concentration of extra-heavy crude petroleum in a clayey material and the toxicity, field capacity, temperature, and growth of a tropical forage grass (Brachiara humidicola) was determined empirically. For this type of petroleum the acute toxicity (Microtox^®) was slight (CE₅₀ = 63200 - 76400 mg/kg) even at high hydrocarbon concentrations (29279 mg/kg). Nonetheless, serious impacts were encountered in terms of an increase in soil temperature (+ 1.3 °C), reduction in field capacity (-10.7%) and reduction in aerial biomass (-97%). The relationship between hydrocarbon concentration and biomass resulted in a typical dose-response curve (r = 0.99), where a concentration of 2626 mg/kg of hydrocarbons corresponds to a maintenance of 90% biomass. Furthermore, during the duration of this study (one year) the biodegradation was proportional to the pasture biomass production (r = 0.997) indicating a synergistic relationship between the petroleum biodegrading microorganisms in the rhizosphere and the pasture.