Beta-Adrenergic relaxation in bovine coronary arteries is enhanced by inhibition of eicosonoid metabolism and inhibited its stimulation. We investigated the interaction between beta-adrenergic mechanisms studying effect perturbations on vascular adenosine 3',5'-monophosphate (cAMP) content cAMP-dependent isometric force activation glycogen phosphorylase. KCl (35 mM) elicited a contraction, activated phosphorylase, slightly decreased cAMP content. Isoproterenol (10(-7) M) relaxed further...

The vasoactive effects of media obtained from bovine aortic endothelial cells (EC) in culture were directly tested on isolated rings the porcine left anterior descending coronary artery. Increasing concentrations EC-conditioned resulted progressive dose-dependent increments isometric tension porcine, bovine, and canine arteries; response did not require an intact endothelium. Control (nonconditioned) that conditioned by fibroblasts or vascular smooth muscle had negligible vessel tone....

In a recent study, the well-documented tumor targeting properties of antitumor agent bleomycin (BLM) were studied in cell culture using microbubbles that had been derivatized with multiple copies BLM. It was shown BLM selectively targeted MCF-7 human breast carcinoma cells but not "normal" line MCF-10A. Furthermore, it found analogue deglycobleomycin, which lacks disaccharide moiety BLM, did target either line, indicating is necessary for selectivity. Not resolved earlier study issues...

The metabolism of vascular smooth muscle is characterized by an unusual component aerobic glycolysis. Lactate production, even under fully oxygenated conditions, similar magnitude to the rate oxygen consumption when compared on a molar basis. Although underlying mechanisms are unknown, ratio glycolytic oxidative has been suggested be index myopathy. Measurements O2 (JO2), lactate production (Jlac), and isometric force in porcine coronary arteries were made conditions known alter both active...

The disaccharide moiety is responsible for the tumor cell targeting properties of bleomycin (BLM). While aglycon (deglycobleomycin) mediates DNA cleavage in much same fashion as bleomycin, it exhibits diminished cytotoxicity comparison to BLM. These findings suggested that BLM might be modular nature, composed tumor-seeking and tumoricidal domains. To explore this possibility, analogues were prepared which was attached deglycobleomycin at novel positions, namely, via threonine or C-terminal...

Although a linkage between aerobic glycolysis and sodium-potassium transport has been demonstrated in diaphragm, vascular smooth muscle, other cells, it is not known whether this occurs skeletal muscle generally. Metabolism of intact hind-leg muscles from young rats was studied vitro under incubation conditions. When sodium influx into rat extensor digitorum longus (EDL) soleus facilitated by the ionophore monensin, weight gain production lactate alanine were markedly stimulated...

Macrophage polarization refers to how macrophages have been activated at a given point in space and time. Polarization is not fixed, as are sufficiently plastic integrate multiple signals, such those from microbes, damaged tissues, ...Read More

Ribosomally mediated protein biosynthesis is limited to α-L-amino acids. A strong bias against β-L-amino acids precludes their incorporation into proteins in vivo and also vitro the presence of misacylated β-aminoacyl-tRNAs. Nonetheless, earlier studies provide some evidence that analogues aminoacyl-tRNAs bearing β-amino can be accommodated ribosomal A-site. Both functional X-ray crystallographic data make it clear exclusion as participants synthesis a consequence architecture...

Plasmids containing 23S rRNA randomized at positions 2057–2063 and 2502–2507 were introduced into Escherichia coli, affording a library of clones which produced modified ribosomes in addition to the pre-existing wild-type ribosomes. These screened with derivative puromycin, natural product acts as an analogue 3′-end aminoacyl-tRNA terminates protein synthesis by accepting growing polypeptide chain, thereby killing bacterial cells. The puromycin this study contained dipeptide...

In an earlier study, β3-puromycin was used for the selection of modified ribosomes, which were utilized incorporation five different β-amino acids into Escherichia coli dihydrofolate reductase (DHFR). The selected ribosomes able to incorporate structurally disparate DHFR, in spite use a single puromycin individual clones. this we examine extent structure employed ribosome influences regio- and stereochemical preferences during protein synthesis; mechanistic probe suppressor tRNACUA activated...

All four of the muscle actins (skeletal, cardiac, vascular, and enteric) in higher vertebrates show distinct expression patterns display highly conserved amino acid sequences. While it is hypothesized that each isoactins specifically adapted to its respective tissue minor variations among them have developmental and/or physiological relevance, exact functional significance these proteins remains largely unknown. In order begin assess issues, we disrupted skeletal actin gene by homologous...

Recent work on vascular smooth muscle actomyosin has indicated that the Ca2+ sensitivity of both ATPase and superprecipitation are affected by calmodulin (CaM) cyclic AMP-dependent protein kinase (cPK). Using a "chemically skinned" arterial preparation, we have extended these observations to intact structured contractile system. Media from hog carotid artery were skinned with 1% Triton X-100 followed 50% glycerol-ATP salt solution, in which strips stored at -25 degrees C. Small (thickness...

A smooth muscle plasma membrane vesicular fraction (PMV) purified for the (Ca2+/Mg2+)-ATPase has endogenous glycolytic enzyme activity. In presence of substrate (fructose 1,6-diphosphate) and cofactors, PMV produced ATP lactate supported calcium uptake. The cascade supports uptake independent bath [ATP]. 10-fold dilution PMV, with resultant glycolytically [ATP] did not change fueled (nanomoles per milligram protein). Furthermore, by persisted in a hexokinase-based trap which eliminated...

1. Basal and recovery O2 consumption, delatO2, in frog sartorius muscles at 0 degrees C were measured with a polarographic electrode. Reproducible observations made the same muscle over many hours. 2. The experimental records had an exponential form except for early phases of following single isometric tetanus. Diffusion within was adequate to account this deviation from time course recovery. constant consumption increased duration tetanic stimulation 5 20 sec. 3. Lactate synthesis...

1. The specific contributions of aerobic glycolysis and oxidative metabolism to Na+ pump activity were quantitated in porcine carotid arteries under conditions. 2. Active reaccumulation potassium by potassium‐depleted tissues could be supported alone, anaerobic the presence glucose, or a combination glycolysis, but not conditions absence glucose. 3. Increasing levels added resulted first stimulation lactate release which saturated at 0.028‐0.036 mumol min‐1 g‐1, was then followed metabolism....

In vascular smooth muscle, oxidative phosphorylation and glycolysis are independently regulated. Previous studies indicated that the independent regulation of these pathways was related to a compartmentation carbohydrate metabolism. To further study metabolism, glucose transport incorporation radiolabel from into glycogen lactate were measured after glycolytic altered. Ouabain stimulated mechanical activity, oxygen consumption, glycogenolysis, whereas production decreased. Although...

The energetics of smooth muscle is characterized by low tension cost (rate ATP utilization per isometric force/cross-section area), ranging from 100- to 500-fold less than skeletal muscle. efficiency (ATP usage work) muscle, although well documented, also somewhat (4-fold) Another well-known characteristic the linear relation between steady-state (JATP) and force. Recently, Murphy colleagues [C.-M. Hai R. A. Murphy. Am. J. Physiol. 254 (Cell 23) C99-C106, 1988] have put forth a kinetic model...

The relation between PO2 and vessel tone was studied in isolated porcine left descending coronary artery rings. Porcine mounted isometrically equilibrated Krebs-bicarbonate solution (37 degrees C, pH 7.4, when gassed with 95% oxygen + 5% carbon dioxide) exhibited spontaneous basal tone. Decreasing bath to 40%, 20%, 12% elicited sustained increases tension which were reversible, ranging 10% 20% of the contraction induced by 40 mM potassium chloride. Further decreases near zero (anoxia)...

Unloaded shortening velocity, a mechanical parameter associated with the rate of cross-bridge cycling, was investigated in chemically skinned guinea pig taenia coli and hog carotid artery. Shortening velocity measured by technique described Edman, whereby large length steps are rapidly imposed on muscle time under unloaded conditions is determined from isometric myograms. this manner similar to Vmax Hill force-velocity relations reported for both living coli, and, case artery, at least as...

1. Measurements of intitial chemical changes and recovery oxygen consumption (deltaO2) were made in unpoisoned aerobic frog sartorius muscles at 0 degrees C to provide independent measures the energy used for isometric tetani various durations. 2. DeltaO2 was measured polarographically increased a curvilinear fashion with stimulus duration. For stimulations longer than 4 sec deltaO2 linear function tension-time integral. 3. content phosphorylcreatine, 'free' creatine inorganic phosphate...

Previous studies (Paul, R. J. Chemical energetics of vascular smooth muscle. In: Handbook Physiology: The Cardiovascular System. Bethesda, MD: Am. Physiol. Soc., 1980, p. 201-235) have shown that oxygen consumption reaches a steady state at approximately twice the basal rate during maintenance isometric contraction. time course attainment metabolic state, signal for observed increase in respiration, and contribution endogenous phosphagens to contraction are not known with certainty. To this...

Purification of cell type-specific RNAs remains a significant challenge. One solution involves biosynthetic tagging target RNAs. RNA via incorporation 4-thiouracil (TU) in cells expressing transgenic uracil phosphoribosyltransferase (UPRT), method known as TU-tagging, has been used multiple systems but can have limited specificity due to endogenous pathways TU incorporation. Here, we describe an alternative that requires the activity two enzymes: cytosine deaminase (CD) and UPRT. We found...