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T Glonek

Publications and source records attributed to T Glonek.

At least 73 records · Page 4Linked to original sources
PubMed1989

Phosphatic metabolites in keratoconus.

Sixteen corneal buttons were obtained from 16 patients with keratoconus at the time of penetrating keratoplasty (mean age, 34 +/- 3.2 yr) and prepared for phosphorus-31 nuclear magnetic resonance spectroscopy following perchloric acid extraction. The corneas were compared with age-matched corneas from fresh eye-bank eyes with normal slit-lamp biomicroscopic appearance. Higher levels (P less than 0.05) of nucleoside monophosphates and choline phosphate and lower levels (P less than 0.05) of adenosine diphosphate were detected in keratoconus than in eye-bank corneas. The level of an unidentified metabolite at 3.96 delta, present in eye-bank corneas, was ninefold higher in keratoconus corneas. Another unidentified metabolite at 3.31 delta, accounting for 1.5% of the total detected phosphatic metabolites, appeared in keratoconus but not in eye-bank cornea spectra. These findings of altered phosphatic metabolites are consistent with altered corneal metabolism. The unidentified, unknown metabolites in the spectral profile uniquely distinguish keratoconus from eye-bank corneas.

Adenine Nucleotides↗
PubMed1989

Interspecies analysis of corneal phosphate metabolites.

Phosphate metabolite profiles of corneas were determined for human, baboon, monkey, cat, guinea-pig, pig, dog, rabbit, and cow using 31P-nuclear magnetic resonance (NMR) spectroscopy. Metabolites quantitatively measured included the low-energy metabolites: hexose 6-phosphates, alpha-glycerophosphate, unassigned phosphorus compound(s) at 4.26-3.91 delta, ethanolamine phosphate, nucleoside monophosphates, choline phosphate, inorganic orthophosphate, phosphodiesters (glycerol 3-phosphoethanolamine and glycerol 3-phosphocholine), and the high-energy metabolites: phosphocreatine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), nucleoside diphosphosugars and dinucleotides. The number of significant differences in metabolites among the species studied, relative to humans, increased in the following order: baboon less than monkey approximately pig approximately cow less than cat approximately guinea-pig less than rabbit less than dog. The 31P energy modulus (human, 1.3 +/- 0.20 S.D.). ATP:Pi ratio (human, 0.5 +/- 0.05 S.D.). ATP:ADP ratio (human, 0.38 +/- 0.34 S.D.). ATP:ADP plus Pi ratio (human, 0.43 +/- 0.04 S.D.) and SP:Pi ratio (human, 0.37 +/- 0.04 S.D.) were determined for each species. All these ratios are indicators of corneal metabolic status, and their values suggest that, of the common laboratory research animals examined, the baboon and monkey are the most like man, and the rabbit and cow the least like man.

Animals↗
PubMed1989

31P NMR of tissue phospholipids: a comparison of three tissue pre-treatment procedures.

Extracted tissue phospholipid 31P NMR profiles, obtained from individual porcine lenses subjected to two preservation procedures (acetone desiccation and freeze-drying) and a perchloric acid-extraction procedure, were compared to those from freshly excised lens specimens. Each profile yielded quantitative data on 12 lens phospholipids: PC, LPC, PC plas, PE, LPE, PE plas, PS, SPH, PI, LPI, PG, and CL. A specimen group size of at least 9 lenses was required for secure statistical inter-group comparisons by the Scheffé procedure, due to specimen 31P NMR profile variability, interpreted as arising from specimen biological variability. The phospholipid profiles of lenses preserved by acetone desiccation were essentially identical to those from the freshly excised control lenses. Freeze-dried lens profiles differed significantly in four components, while profiles from perchloric acid-extracted lenses differed in six. It is concluded that specimen preservation by acetone disiccation is a useful method for preserving tissue phospholipids for subsequent 31P NMR profile analysis, while freeze-drying is not. Lipid extraction following a tissue acid extraction is also of little or no value in the determination of tissue phospholipid profiles.

Animals↗
PubMed1988

31P magnetic resonance spectroscopic profiles of neoplastic human breast tissues.

Phosphorus-containing metabolites of human breast tissues from malignant, benign, and noninvolved breast parenchymal specimens were examined by using techniques of perchloric acid extraction and 31P magnetic resonance spectroscopy. Twenty-four separate resonances arising from the established phosphorylated metabolites of high-energy- and low-energy-phosphate intermediary metabolism were identified and quantitated. Subsequent to magnetic resonance spectroscopic analysis, the data from the three tissue groups were compared and contrasted on a statistical basis by using Scheffé simple and complex contrast procedures. Theories of tumor metabolism and biochemical interactions were invoked, including the tissue high-energy-/low-energy-phosphate modulus, the phosphomonoester/Pi ratio, and 10 other metabolic indices. The data demonstrated the ability of 31P magnetic resonance spectroscopy to differentiate among the three tissue groups. Both benign and malignant tumors demonstrated comparable Warburg effects. Phosphomonoester metabolism was shown to be altered in neoplastic tissues relative to the noninvolved tissues. Phosphocreatine was elevated in benign tumors. This elevation in phosphocreatine plus a parallel elevation in an uncharacterized phosphate resonating at a chemical shift of 3.66 delta permits the important differentiation between malignancy and benignancy in human breast disease. The tissue energy modulus indicated that benign tissue is relatively more aerobic than noninvolved tissue and significantly more aerobic than malignant tissue.

Biomarkers, Tumor↗
PubMed1988

Effects of the slow calcium-channel blocker verapamil on phosphatic metabolism of crystalline lens.

The effects of calcium-channel blockade on phosphate metabolism in the rabbit lens ex vivo was studied using phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy. Rates-of-change of the intralenticular pH and the following phosphatic metabolites in the lens were determined: ATP, ADP, inorganic orthophosphate, sugar phosphates, nucleoside diphosphosugars, phosphodiesters, dinucleotides, and an uncharacterized resonance peak at 6 delta in the 31P spectrum. Incubation in 20, 200 or 2000 micrograms/ml verapamil led to the same qualitative changes in the lens's metabolic profile at each different concentration; only the rates of metabolite change were altered significantly by verapamil concentration. Compared with the control, the entire orthophosphate resonance band increased relative to the signals of ATP, and the alpha-glycerophosphate and nucleoside monophosphate resonances increased in relation to inorganic orthophosphate, and these two resonance groups shifted relative to each other so that they coalesced, indicating that the two groups of signals arose from compounds in relatively different pH compartments. In addition to altering metabolic rates, verapamil reduced the intralenticular pH of the sugar phosphate and inorganic orthophosphate pools with respect to those containing the nucleoside monophosphates; the pH-change difference was about one order of magnitude smaller for the mononucleotide pool. Despite the metabolic alterations and changes in pH during verapamil incubation, lens clarity was unchanged.

Adenosine Diphosphate↗
PubMed1988

pH of organ-culture-stored corneas.

Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea.

Animals↗
PubMed1988

Effects of moist-chamber and McCarey-Kaufman medium storage on the metabolic status of the cornea: a 31P-magnetic resonance analysis.

The rate of change in concentration of corneal phosphatic metabolites of cat corneas stored in moist chamber and McCarey-Kaufman (M-K) medium was determined in order to provide a basis for prediction of the corneal metabolic status at a given storage time. Perchloric acid corneal extracts were examined by phosphorus-31 magnetic resonance after storage at 4 degrees C of whole globes under moist-chamber conditions up to 48 h and of excised corneas in M-K medium up to 168 h. A significant decline in the corneal concentrations of ATP and a significant increase in inorganic phosphate occurred for both storage methods; however, depending on the metabolite, the rate of decline or increase was significantly greater for the moist-chamber-stored corneas. The phosphorylated sugars significantly increased and the glycerophosphodiesters significantly decreased in the moist-chamber-stored corneas, whereas both metabolites remained unchanged in the M-K-medium-stored corneas. There was no significant change in the dinucleotides and nucleoside diphospho-sugars during the time course for both storage methods. A threefold greater rate of decline was noted in the tissue energy modulus for the moist-chamber-stored corneas than for the M-K-medium-stored corneas (-0.0465 vs. -0.0121 modulus values/h). M-K medium was significantly more effective in the maintenance of high-energy phosphatic metabolites. The mathematical model for these rate determinations provides a basis for prediction of the corneal metabolic status at a given time in moist-chamber or M-K medium storage.

Adenosine Triphosphate↗
PubMed1988

High resolution 31P NMR of extracted phospholipids.

The common phospholipids from biological sources were quantitated using phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy in conjunction with an analytical reagent composed of two parts: 1) 2 ml of reagent chloroform in which was dissolved 0.01-100 mg of crude tissue lipid extracted from tissue sources using chloroform-methanol 2:1, the extract having been washed with 0.2 vol. of 0.1 M KCl; 2) 1 ml of an aqueous methanol reagent composed of one part 0.2 M (ethylenedinitrilo)-tetraacetic acid in D2O titrated to pH 6 with CsOH and four parts of reagent methanol. In a magnetic field of 11.75 Tesla, the extracted phospholipids yield narrow signals (1.8-3.2 Hz at half-height), corresponding to each generic species, e.g., phosphatidylcholines, phosphatidylethanolamines, etc., permitting resolution among the various phospholipid families and their lyso and plasmalogen derivatives. The reagent permits assays of high precision and accuracy using a modest amount of NMR spectrometer time (ca. 15 min/assay). The procedures described, which are compared to high-performance liquid chromatography, are convenient for the routine analysis of phospholipids from biological sources.

Animals↗
PubMed1987

Metabolism of 2-aminoethylphosphonic acid during embryonic development of the schistosomal vector Biomphalaria glabrata.

1. Egg masses of the Planorbid snail Biomphalaria glabrata contain 2-aminoethylphosphonic acid (AEP) in three different chemical environments, as determined by 31P nuclear magnetic resonance spectroscopy, giving signals at 20.9, 21.0 and 23.4 delta. 2. The signal at 21.0 delta decreased in intensity during embryonic development, whereas the other two did not change significantly. 3. The following relationship is suggested: Extraembryonic AEP--------Intraembryonic AEP--------Phosphates. 4. pH Titration behavior of macromolecularly-bound AEP and synthetic derivatives of AEP was examined and indicates that AEP is found in the egg masses linked to other molecules in the following ways: (a) R2-NH-CH2CH2-P(O)(OH)(OR1), (b) R3-NH-CH2-P(O)(OR2)(OR1), (c) NH2-CH2CH2P(O)(OH)(OR1).

Aminoethylphosphonic Acid↗
PubMed1987

Preoperative metabolic analysis of donor corneas using magnetic resonance spectroscopy.

Successful corneal transplantation was accomplished following metabolic phosphorus magnetic resonance analysis. Four cat corneas were analyzed using phosphorus-31 magnetic resonance following storage in modified McCarey-Kaufman (M-K) medium for 24 h. Corneas were re-stored in M-K medium and transplanted 24 h after MR analysis. Four control corneas (contralateral eye, no magnetic resonance analysis performed) were also transplanted following storage in M-K medium under identical conditions. Successful corneal transplantation was accomplished with minimal ATP tissue levels. Corneas stored for 48 h maintained a pH of 7.3. The phosphorus-31 spectral modulus, which is the ratio of the high-energy phosphates to the low-energy phosphates, was calculated using the spectral integral (range, 0.49-0.77). No difference in endothelial cell density or morphology was detected between corneas following magnetic resonance analysis and control corneas when evaluated by specular microscopy.

Animals↗
PubMed1987

31P nuclear magnetic resonance studies of phosphoglyceride metabolism in developing and degenerating brain: preliminary observations.

31P nuclear magnetic resonance (NMR) studies were conducted on perchloric acid extracts of the brain of one control, two Huntington's disease (HD), one probable Alzheimer's disease (AD), and one AD patient. These studies demonstrated significant elevations (over control) in the levels of phosphomonoesters in all brain areas of the patients with HD and AD even in areas devoid of neuropathological findings. Elevations of phosphodiesters were also observed, but they tended to reflect the degree of neuropathological change. We postulate that the 31P NMR findings represent molecular alterations with corresponding metabolic correlates which either antedate or occur in the absence of changes in cellular morphology or structure. As such the 31P NMR findings may reflect a subcellular "molecular neuropathology."

Adult↗
PubMed1986

31P-nuclear magnetic resonance analysis of extracts of vascular smooth muscle.

31P-nuclear magnetic resonance spectroscopy was used to assess phosphate metabolites in perchloric acid extracts of rabbit aorta. In addition to the high energy phosphates, several other phosphorus compounds were detected and quantified. Most notable was the presence of a prominent phosphomonoester compound appearing at a chemical shift of 3.86 delta. This compound constituted 26% of the total extractable tissue phosphorus and is tentatively identified as ribose-5-phosphate, a pentose phosphate pathway intermediate. While ATP and phosphocreatine did not change during glucose and oxygen deprivation or during prolonged muscle contraction, the 3.86 delta phosphate decreased significantly. Furthermore, theophylline, an agent that increases intracellular cAMP, also decreased the level of the 3.86 delta phosphate. These results are consistent with the concept that intermediate metabolism sustains high energy phosphate pools in vascular smooth muscle in the steady state under various conditions. The pentose phosphate pathway may play an important role in vascular smooth muscle metabolism.

Animals↗
PubMed1985

Lenticular energy metabolism during exogenous calcium deprivation and during recovery: effects of dextran-40.

Phosphatic metabolites of the intact rabbit lens were quantitated as a function of time by phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy during in vitro incubations at 37 degrees C in calcium-sufficient and calcium-deficient modified Earle's buffer with and without the osmotic agent, Dextran-40. Intralenticular pH was determined from the resonance shift position of inorganic orthophosphate (Pi). Incubation of lenses in calcium-deficient buffer resulted in a pronounced, time-dependent decrease in lenticular adenosine triphosphate (ATP) levels. The half-life of ATP within the lens was 11 hr under these experimental conditions. A concomitant, essentially stoichiometric increase in adenosine diphosphate and Pi levels was observed also. The other phosphatic metabolites were unaffected by exogenous calcium deprivation except for adenosine and inosine monophosphate which accumulated with time. Dextran-40 (6%), which has been shown to prevent lens swelling under these same experimental conditions, did not influence the metabolic responses of the lens to external calcium deprivation and did not facilitate subsequent restoration of lens phosphatic metabolites following restoration of a physiologic calcium concentration to the supporting medium. The Dextran-40 did, however, promote the retention of intralenticular pH environment during the experimental period. These findings suggest that the previously reported Dextran-40-dependent recovery of intralenticular sodium and potassium concentrations to control levels following 10 hr of incubation in calcium-deficient media cannot be attributed to a direct energy-sparing action of Dextran-40 on lenticular energy metabolism. Instead, the mechanistic basis for the action of Dextran-40 would appear to be related to its colloid osmotic properties and its ability to prevent lenticular swelling, which otherwise occurs in the absence of Dextran under these experimental conditions.

Adenosine Diphosphate↗
PubMed1985

Distribution of phosphatic metabolites in the porcine cornea using phosphorus-31 nuclear magnetic resonance.

This study describes the phosphatic metabolite contribution of the porcine corneal stroma [by phosphorus-31 nuclear magnetic resonance (P-31 NMR)] and the corneal epithelium (by difference calculation) to the total phosphatic metabolic profile of the intact (i.e. whole, undissected) cornea. In order to provide such a regional analysis, the epithelium and endothelium were surgically removed from three sets of 12 corneas. Three additional sets of 12 intact corneas were used as controls. Histological examination of two randomly selected stromata from each set of corneas were analyzed to verify that epithelium and endothelium were removed. Perchloric acid extracts were prepared from the 10 remaining stromata for P-31 NMR analysis. Twenty phosphatic metabolites were measured including six unidentified (unknown) signals. Components with diminished relative concentrations in the stromal profile compared to that of the intact cornea profile are: the triose and hexose phosphates associated with glycolysis (including alpha-glycerophosphate), choline phosphate, ATP, uridine diphosphohexoses and the unknown compound resonating at 0.93 delta. The relative level of inorganic phosphate in the stroma is nearly doubled. The remaining measured phosphates are not significantly changed relative to the total extractable phosphorus content. Consistent with previous biochemical findings, phosphates associated with energy metabolism are found primarily in the epithelial fraction. The metabolic status of the endothelial monolayer cannot be assessed because of low tissue mass and the relatively low sensitivity of P-31 NMR spectroscopy. This study serves as baseline data for the interpretation of experimental and clinical phosphorus NMR data from intact cornea by providing the contribution to the whole corneal spectrum of metabolites of the individual corneal layers.

Animals↗
PubMed1985

Phosphorus-31 NMR analysis of dynamic energy metabolism in intact crystalline lens treated with ouabain: phosphorylated metabolites.

Changes in phosphatic metabolites and intralenticular pH of the intact crystalline rabbit lens induced by ouabain (10(-3), 10(-4), 10(-5) M) were measured during time-course incubations using phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) in order to study the metabolic manifestations of this steroid on lens glycolytic activity. Significant alterations in the glycolytic intermediates of the crystalline lens only occurred with ouabain at the concentration of 10(-3) M. A significant time-dependent increase in alpha-glycerophosphate, an unidentified pentose phosphate, the nucleoside diphosphosugars (uridine diphosphoglucose and uridine diphosphomannose), inorganic orthophosphate, and inosine monophosphate, and decline in glucose 6-phosphate and ATP were detected in 10(-3) M ouabain-treated lenses. The uridine diphosphosugars exhibited a maximum at approximately the time when the lens ATP content was 50% of control levels (12.5 h). A progressive decrease in intralenticular pH indicative of hydrogen-ion-pump damage was detected concomitant with the changes in lens metabolite levels. Lenses maintained transparency throughout the time-course. Since metabolite manifestations effecting the intermediates of glycolysis occur in lens tissue with its high glycolytic and low oxidative activity, we hypothesize the effects of 10(-3) M ouabain may represent metabolic actions of ouabain which are independent of its effects on tissue oxygen consumption as is presumed from studies involving tissues more dependent on oxidative metabolism.

Adenosine Diphosphate↗
PubMed1985

Distribution of phosphatic metabolites in the crystalline lens.

The phosphatic metabolite content of specific anatomic regions within the crystalline lens was determined by phosphorus-31 nuclear magnetic resonance analyses performed on tissue perchloric acid (PCA) extracts. Anatomically distinct zones each were dissected from five sets of 10 porcine lenses, isolated, and frozen in liquid N2. Separate pooled-tissue PCA extracts were prepared for each set of lens tissue corresponding to the following anatomic regions: capsule with attached epithelium, cortex, and nucleus. Randomly selected tissues were evaluated by light microscopy to determine the accuracy of the described dissection technique. Thirty-four phosphorus-containing metabolites were detected and quantitated by P-31 NMR from each of the three zones studied. Included among the phosphatic metabolites of these lens tissues were 18 chemically unidentified compounds. Significant regional differences in the metabolite distribution pattern were detected. The levels of ATP in the capsule + epithelium and in the cortex were 2.2-fold and 3.2-fold higher, respectively, than in the nucleus. In contrast, the Pi content was 2.3-fold greater in the capsule + epithelium and nucleus than in the cortex. End products of phospholipid metabolism (eg, glycerol 3-phosphocholine) also varied according to the anatomic region, with the highest content found in the nucleus. The prominent unidentified lens metabolite at 6 delta was highest in the nucleus, 35% lower in the cortex, and quite low in the capsule + epithelium. When individual P-31 NMR spectral profiles from each zone were summed according to normalized weighting factors, which reflected the relative phosphorus concentration of each region, a spectral profile of the lens was generated that was essentially indistinguishable from that of the whole (undissected) lens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗