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T Glonek

Publications and source records attributed to T Glonek.

At least 109 records · Page 6Linked to original sources
PubMed1981

Organophosphates of the crystalline lens: a nuclear magnetic resonance spectroscopic study.

We quantitated the concentrations of the principal organophosphate metabolites present in the intact crystalline rabbit lens, measured the intralens pH, and evaluated dynamic changes during 24 hr incubations, using phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy. Tissue perchloric acid extracts prepared from these same lenses were analyzed by this technique to verify metabolite identifications and to quantitate the concentrations of the minor lens metabolites. Values for lens organophosphate concentrations, including three groups of previously unidentified phosphorus-containing substances, were established for freshly excised lenses, 24 hr incubated lenses, and lenses incubated in glucose-deficient media. Lens metabolite levels were not adversely affected by incubation in a medium previously shown to maintain lens clarity and ion transport capabilities. Conversely, lens incubation in glucose-deficient media induced significant metabolic changes characterized by a time-dependent decline in ATP, corresponding increases in ADP, inorganic phosphate, and phosphorylated hexoses. Cataract formation was noted after incubation in this medium. These findings support the hypothesis that alterations in the organophosphate levels of the lens actually preceded changes in the Na+ and K+ concentrations and therefore may be the "initiating factor" in formation of lens cataracts.

Animals↗
PubMed1980

Cardiac physiologic-metabolic changes after chronic low-level heavy metal feeding.

Female Long-Evans hooded rats received 0 or 5 parts per million Cd, Pb, or Cd + Pb in the drinking water from weaning to 20 mo. Growth, measured as body weight, and organ weights were comparable among heavy metal and control animals. Indirect blood pressure responses measured trimonthly are discussed. Analysis of His bundle electrograms (HBE) and electrocardiograms recorded in sodium pentobarbital-anesthetized animals at 20 mo demonstrated that Cd selectively depressed conduction system excitability proximal to the common His bundle (atrioventricular node region), whereas Pb and Pb + Cd impaired conductivity distal to the common His bundle (His-Purkinje system). Perchloric acid extracts of liquid N2-freeze-clamped isolated perfused hearts, derived from a subpopulation of control and Cd-fed rats in which HBE analyses were not performed, were analyzed by phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopic techniques to quantitate [31P]phosphate metabolite profiles. Cardiac active tension and atrioventricular node excitability were depressed in the Cd group. High-energy phosphate and glycerol 3-phosphorylcholine concentrations were depressed. Results demonstrate potentially significant pathophysiological changes within cardiovascular tissues that develop in the absence of overt heavy metal toxicity manifestations.

Animals↗
PubMed1979

Phosphorus 31 NMR of neuroblastoma clonal lines. Effect of cell confluency state and dibutyryl cyclic AMP.

Phosphorus nuclear magnetic resonance is used to study changes in the levels of the major phosphate-containing intermediary metabolites concomitant with induced cellular differentiation in the N-18 and C-46 neuroblastoma clonal lines. The study reveals differences between the 31P-NMR profiles of the two clonal lines and also striking differences attendant to dibutyryl cAMP-mediated morphological differentiation in the N-18 clone. Phosphorus-31 NMR would appear to provide a new technique with which to study genetic differentiation.

Animals↗
PubMed1979

Phosphodiesters in muscular dystrophies.

Phosphorus nuclear magnetic resonance studies of various normal and dystrophic muscles have demonstrated differences in phosphodiester contents. Dystrophic chicken pectoralis muscle contains elevated levels of the diester SEP, and Duchenne dystrophic human leg muscle lacks the diester GPC. It is shown that SEP may be characteristic of slow fiber types, indicating imcomplete maturation of the dystrophic pectoralis muscle. The activities of SEP-metabolizing enzymes have been determined in microsomes of pectoralis muscle, kidney, and intestinal mucosa of normal and dystrophic chickens. There was little difference between normal and dystrophic values of SEP phosphodiesterase and SEP synthase in kidney and mucosa. Dystrophic pectoralis muscle microsomes possessed significantly elevated levels of both enzymes. The increase in SEP synthase activity of dystrophic muscle may explain the increase in the SEP level if the phosphodiesterase is regulated in vivo. It is shown that human muscle disease processes may raise, leave unchanged, or lower GPC levels. In certain diseases when GPC is markedly elevated, such as Werdnig-Hoffmann, or depressed, such as Duchenne muscular dystrophy, it may serve as a marker.

Animals↗
PubMed1978

31P magnetic resonance of intact endocrine tissue: adrenal glands of dogs.

Intact dog adrenal glands were examined for their phosphate profiles in the 31P nuclear magnetic resonance spectrometer at 36.43 MHz at 31 degrees, and the resultant spectra were compared to those obtained from perchloric acid extracts of the same endocrine tissue. The adrenal gland presents a unique organ for whole tissue spectroscopy in that its phosphate profile shows a number of features which have not been previously observed in similar phosphate profiles obtained from other intact tissue preparations. A number of prominant resonances are observed in the intact adrenal gland which arise from phosphorus-containing substances that are not extractable with perchloric acid. The 31P shifts of these resonances indicate that they may arise from phosphorylated proteins and membrane phospholipids.

Adenine Nucleotides↗
PubMed1977

Analysis of living tissue by phosphorus-31 magnetic resonance.

Nuclear magnetic resonance is a new method for assaying the content of phosphate metabolites in intact tissues. Its nondestructive nature allows simultaneous and repeated determinations of these compounds with a minimum perturbation of tissue. Changes in the concentrations of the phosphates as a function of time characterize the metabolic machinery of the tissue and reveal alterations in enzymic activity that result from drug treatment or disease. The entire phosphate profile shows differences between normal and diseased muscle which should be of diagnostic value. Further, by examining phosphate profiles we detected a family of chemical compounds that were not previously known to exist as major constituents in muscle. Of these, two have been isolated and one has been identified as glycerol 3-phosphorylcholine. Finally, shifts in the positions of resonances monitor the internal environment of the living system, its hydrogen ion concentration, the complexing of alkaline earth metals with ATP, and compartmentalization within the cell.

Adenosine Triphosphate↗
PubMed1976

Phosphorus-31 nuclear magnetic resonance detection of unexpected phosphodiesters in muscle.

In the examination of intact muscles by 31P nuclear magnetic resonance spectroscopy, a number of signals have been detected in the phosphodiester region (-0.5 to 0.5 ppm) of the spectrum which could not be correlated with the known common phosphates of muscle tissue. These signals arise from perchloric acid extractable compounds with several common chemical properties, one of which is a ready solubility in nearly anhydrous ethanol solutions. A component contributing to the major resonance has been identified as glycerol-3-phosphorylcholine. This characterization is based on both 31P nuclear magnetic resonance and chromatographic data.

Animals↗
PubMed1976

Comparison of the phosphorus magnetic resonance and circular dichroism properties of calf thymus DNA and chromatin.

Dual measurements of the 31P magnetic resonance spectra and the circular dichroism spectra have been made on calf thymus DNA and purified chromatin. The 31P magnetic resonance signals for all samples fell at 1.2 +/- 0.1 ppm relative to 85% orthophosphoric acid. The full width at half-height of the signal of samples in which the molecular weight of the native DNA component was in the 2-9 X 10(6) range was ca. 50 Hz. This bandwidth was reduced dramatically to ca. 20 Hz by reducing the molecular weight to 140 000 (by sonication) or by heat denaturation of the high-molecular-weight DNA. The position of the signal and the bandwidth of the chromatin samples did not differ significantly from that of the DNA samples of comparable molecular weight and state of nativity. The intensities of the chromatin signals, however, were all less than those of signals of DNA in companion runs conducted under comparable experimental conditions. The reduction of the intensity of the magnetic resonance signal paralleled the lowering of the intensity of the positive band above 260 nm in the circular dichroism spectrum of the given sample of chromatin relative to the spectrum of protein-free DNA. In fact, the percent reduction of the magnetic resonance signal of chromatin relative to protein-free DNA was, within experimental error, equal to the percentage of nucleotide residues in the Watson-Crick B secondary structure. Since the latter fraction of residues can be correlated with those in the interbead regions of the superstructure of chromatin, we have concluded that the signal of the nucleotide residues in the beads, or v bodies, has been broadened to the point of extinction by a packing arrangement which maximizes phosphate-protein interactions and structural rigidity.

Animals↗
PubMed1976

Analysis of phosphate metabolites, the intracellular pH, and the state of adenosine triphosphate in intact muscle by phosphorus nuclear magnetic resonance.

31P nuclear magnetic resonance spectra recorded from intact muophosphate, and the sugar phosphates. Quantitation of these metabolites by 31P nuclear magnetic resonance was in good agreement with values obtained by chemical analyses. The spectra obtained from various muscles showed considerable variation in their phosphorus profile. Thus, differences could be detected between (a) normal and diseased muscle; (b) vertebrates and invertebrates; (c) different species of the same animal. The time course of change in phosphate metabolites in frog muscle showed that ATP level remains unchanged until phosphocreatine is nearly depleted. Comparative studies revealed that under anaerobic conditions the Northern frog maintains its ATP content for 7 hours, while other types of amphibian, bird, and mammalian muscles begin to show an appreciable decay in ATP after 2 hours. Several lines of evidence indicated that ATP forms a complex with magnesium in the muscle water: (a) the phosphate resonances of ATP in the muscle were shifted downfield as compared to those in the alkaline earth metal-free perchloric acid extract of the muscle; (b) the coupling constants of ATP measured in various live muscles closely corresponded to those for MgATP in a solution resembling the composition of the muscle water; (c) in the muscle the gamma-phosphate group of ATP exhibited no shift change over a period of 10 hours under conditions where resonances of other phosphate compounds could be titrated. This behavior is similar to that of MgATP in model solutions in the physiological pH range, and it is different from that of CaATP. The chemical shifts of the phosphate metabolites were determined in several relevant solutions as a function of pH. Under all conditions only inorganic orthophosphate showed an invariant titration curve. From the chemical shift of inorganic phosphate observed during aging of intact muscle the intracellular pH of frog muscle was estimated to be 7.2.

Adenosine Triphosphate↗
PubMed1976

Cyclization of the phosphorus chain of the methylene-bridged analogs of adenosine triphosphate.

The phosphorus-containing side chains of two methylene-bridged analogs of adenosine triphosphate have been cyclized to produce the corresponding analogs of monoadenosine-5'-trimetaphosphate. (The structures are given in the journal.) The molecules, which were generated in anhydrous media through a carbodimide-mediated condensation, were characterized by 31P nuclear-magnetic resonance, and the white-noise 1H decoupled spectra were simulated. These molecules are quite reactive and readily converted to their corresponding linear forms upon hydrolysis. The second structure contains an asymmetric phosphorus atom, and both of the possible cyclic molecules have been observed and the diasteroisomeric mixture has been isolated.

Adenosine Triphosphate↗