Interactions between short-term and long-term cardiovascular control mechanisms

The cardiovascular system incorporates several controlling mechanisms acting as feedback loops over different time horizons. Because of their complex interrelationships, information-based methods such as autonomic information flow (AIF) functions promise to be useful in identifying normal and pathological behavior. Optimal adjustment between those controllers is necessary for healthy global behavior of the organism. We investigated the question as to whether there are typical relationships between short-term and long-term AIF by means of a meta-analysis of several of our own clinical studies of the mortality of patients with multiple organ dysfunction syndrome, heart failure, idiopathic dilated cardiomyopathy, and the length of stay in hospital after abdominal aorta surgery. We found a fundamental association of increased short-term randomness (decreased AIF) and decreased long-term randomness (increased AIF) due to pathology. A systems theoretic validation of this fundamental type of association was done by an appropriate mathematical model using a dissipative system with two feedback loops over different time horizons. The systematic simulation of an increasing collapse of the short feedback loop confirmed the inverse association between short-term and long-term information flow as a fundamental, system inherent type of readjustment that occurs under pathological conditions.     

Coibanoles, a new class of meroterpenoids produced by Pycnoporus sanguineus

Three new terpenoids of mixed biosynthetic origin were isolated from the culture filtrate of the endophytic fungus Pycnoporus sanguineus. Their structures were determined by extensive spectroscopic analyses. We have named these tricyclic and tetracyclic metabolites ‘coibanoles A-C’ in reference to Coiba Island and Coiba National Park, Panamá, from which the plant and endophyte were collected. The extract was inactive to the human parasites Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum at a test concentration of 10 μg/mL.     

High-performance liquid chromatographic profiles of low-molecular-weight,u.v.-absorbing compounds in the sera of beagles exposed to cigarette smoke

High-performance liquid chromatography with a nonpolar stationary phase was used to determine the low-molecular-weight, u.v.-absorbing compounds in the sera of male beagles exposed to cigarette smoke. The sera from three groups of tracheostomized beagles were processed. The ChromatographiC profiles of the beagles exposed to the smoke of low-nicotine cigarettes for 610–750 days were not significantly different from the profiles of beagles identically exposed to the smoke of high-nicotine cigarettes. However, several important differences were determined between the profiles of sham controls and the dogs exposed to cigarette smoke. Most notably, a two-fold elevation of serum inosine was found in all beagles exposed to cigarette smoke.     

Complex formation of zirconium and hafnium with xylenol orange

The factors affecting the formation of zirconium and hafnium complexes of xylenol orange (XO) in perchloric acid have been examined. The optimum acid concentration for both systems is in the range 0.2–0.5 M HClO₄. When excess of metal is present, an initial complex with (XO) : metal ratio of 1 :1 is formed; this complex then undergoes an acid-dependent reaction, taking approximately 2 h to reach completion. Rate constants for this reaction have been determined. When excess of xylenol orange is present (i.e.(XO) : metal ? 2) a 2 :1 complex is formed which does not undergo further reaction. Extinction coefficients are given for the various complexes.     

The precipitation of hydrated cobalt 1-nitroso-2-naphtholate from homogeneous solution

A method has been developed for determining cobalt by precipitating cobalt^III 1-nitroso-2-naphtholate from homogeneous solution. The reagent is synthesised within the reaction mixture by treating 2-naphthol with nitrous acid in the presence of cobalt^II ion. Thus nitrous acid serves the dual role as oxidant for the cobalt^II ion and also as a reactant in the synthesis of the reagent. Excess reagent precipitates after the cobalt nitroso-naphtholate has settled. A washing procedure has been developed to eliminate the excess reagent without affecting the cobalt nitroso-naphtholate. After washing to remove excess reagent and filtration, the precipitate is dried at 115° and weighed as Co(C₁₀H₆O₂N)₃·H₂O.

The presence offluoride prevents the interference of iron, tungsten and other elements which form strong fluoride complexes.

The precision and accuracy is within 0-1 mg of cobalt at a 10-mg level and within 0-2 mg of cobalt at a 50-mg level.     

Luminescent homo- and heteropolynuclear platinum(II) chalcogenido aggregates based on [Pt2E2(P empty set N)4] units (E=S,Se)

A series of homodinuclear platinum(II) complexes containing bridging chalcogenido ligands, [Pt(2)(mu-E)(2)(P empty set N)(4)] (P empty set N=dppy, E=S (1), Se (2); P empty set N=tBu-dppy, E=S (3)) (dppy=2-(diphenylphosphino)pyridine, tBu-dppy=4-tert-butyl-2-(diphenylphosphino)pyridine) have been synthesized and characterized. The nucleophilicity of the [Pt(2)E(2)] unit towards a number of d(10) metal ions and complexes has been demonstrated through the successful isolation of a number of novel heteropolynuclear platinum(II)-copper(I), -silver(I), and -gold(I) complexes: [[Pt(2)(mu(3)-E)(2)(dppy)(4)](2)Ag(3)](PF(6))(3) (E=S (4); Se (5)) and [Pt(2)(dppy)(4)(mu(3)-E)(2)M(2)(dppm)]X(2) (E=S, M=Ag, X=BF(4) (6); E=S, M=Cu, X=PF(6) (7); E=S, M=Au, X=PF(6) (8); E=Se, M=Ag, X=PF(6) (9); E=Se, M=Au, X=PF(6) (10)). Some of them display short metal.metal contacts. These complexes have been found to possess interesting luminescence properties. Through systematic comparison studies, the emission origin has been probed.     

Thermal reactions of 8-methylbicyclo[4.2.0]oct-2-enes: competitive diradical-mediated [1,3] sigmatropic, stereomutation, and fragmentation processes

[reaction: see text] At 275 degrees C, 8-exo-methylbicyclo[4.2.0]oct-2-ene (1a) undergoes a [1,3] sigmatropic rearrangement to 5-methylbicyclo[2.2.2]oct-2-enes, of which the orbital symmetry-allowed si product is only marginally favored over the forbidden sr product; that is, si/sr is 2.4. Accompanying the [1,3] shift are significant amounts of epimerization and fragmentation. The 8-endo epimer 1b, which yields no [1,3] product, experiences primarily direct fragmentation and secondarily epimerization. A diradical intermediate can account for all such observations.     

Hydrogen bonding on accessible surfaces of cellulose from various sources and relationship to order within crystalline regions

Celluloses from a variety of common sources were analyzed for availabilities of O(2)H, O(3)H, and O(6)H in order to estimate the extent of hydrogen bonding on accessible fibrillar surfaces. Celluloses from flax, ramie, sisal, and wood (both cellulose I and II from wood) together with liquid NH₃-swollen cotton and NaOH-swollen cotton (cellulose II) had relative availabilities similar to those of native cotton. Celluloses from Valonia centricosa and in rayon samples stood apart from each other and from the “cotton family.” The difference between Valonia and cotton celluloses appears to result, in addition to the accepted smaller, less perfect crystallites in cotton, from an O(2)H hydrogen bond which is likely the intramolecular bond between O(2)H and O(6′)H that is present in Valonia and absent in cotton. Rayon samples also showed evidence of similar bonds involving O(2)H on accessible surfaces. Since the regenerated rayons had relative availabilities different from those of mercerized cotton and wood cellulose samples, it is proposed that chain packing arrangements are not the same in these two types of cellulose II.     

Visualizing Gene Expression in Living Mammals Using a Bioluminescent Reporter

Abstract— Control of gene expression often involves an interwoven set of regulatory processes. As information regarding regulatory pathways may be lost in ex vivo analyses, we used bioluminescence to monitor gene expression in living mammals. Viral promoters fused to firefly luciferase as transgenes in mice allowed external monitoring of gene expression both superficially and in deep tissues. In vivo bioluminescence was detectable using either intensified or cooled charge-coupled device cameras, and could be detected following both topical and systemic delivery of substrate. In vivo control of the promoter from the human immunodeficiency virus was demonstrated. As a model for DNA-based therapies and vaccines, in vivo transfection of a luciferase expression vector (SV-40 promoter and enhancer controlling expression) was detected. We conclude that gene regulation, DNA delivery and expression can now be noninvasively monitored in living mammals using a luciferase reporter. Thus, real-time, noninvasive study of gene expression in living animal models for human development and disease is possible.