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Biomedical subjects

J V Greiner

Publications and source records attributed to J V Greiner.

At least 55 records · Page 3Linked 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↗
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

Papillary conjunctivitis induced by an epithelialized corneal foreign body.

This report of papillary conjunctivitis induced by a corneal foreign body suggests that papillogenesis may result from physical/mechanical tissue trauma. A case is presented with an epithelialized corneal foreign body in the peripheral cornea during a 9-month period. The overlying corneal epithelial surface was elevated, and corresponding upper tarsal conjunctiva revealed localized, elevated papillae. One month after the foreign body was excised, the papillae resolved. An epithelialized foreign body, elevated cornea, and coincidental papillae support the role of physical trauma for the development of papillae--a feature of the syndrome of contact-lens-associated giant papillary conjunctivitis.

Conjunctiva↗
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↗
PubMed1985

Effects of eye rubbing on the conjunctiva as a model of ocular inflammation.

We assessed the effects of eye rubbing on the histologic characteristics and inflammatory cell infiltrate of the conjunctiva. The upper eyelids of 20 adult rats were rubbed during a five-minute period, and then the animals were killed immediately, or at four, eight, or 24 hours after trauma. One eye of each animal was rubbed; the unrubbed contralateral eye served as a control. Counts of mast cells, degranulated mast cells, and inflammatory cells (neutrophils, eosinophils, lymphocytes, plasma cells, and macrophages) were recorded from conjunctival samples from the upper eyelid. Immediately after eye rubbing the conjunctival epithelium was histologically disrupted and 50% of the mast cells showed evidence of degranulation. At four hours after trauma the increase in the number of neutrophils was more than 2,300%. Neutrophils were in the margins in the conjunctival vessels, had migrated into the substantia propria, and were aligned subjacent to the epithelial basement membrane; large numbers of neutrophils populated the epithelium. The four-hour stage was the most dramatic phase of inflammation that occurred from the eye rubbing. At 24 hours there was a significant increase in the number of macrophages. The numbers of lymphocytes, plasma cells, and eosinophils were not significantly changed throughout the study. Our findings demonstrate that eye rubbing histologically disrupts the epithelium and induces significant alteration in the inflammatory cell infiltrate of the conjunctiva. These changes may influence the course of ocular disease.

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

Histochemical analysis of secretory vesicles in nongoblet conjunctival epithelial cells.

An Alcian-blue/Periodic acid Schiff reagent (AB/PAS) pH dependent staining method was used to identify the mucus content of secretory vesicles of non-goblet epithelial cells of the human conjunctiva. Twenty subjects were selected for biopsy of the midcentral upper tarsal conjunctiva: 10 subjects had no contact lens wearing experience, and 10 subjects wore contact lenses. Human respiratory epithelium was used as a control for the staining procedure. Four-micron paraffin sections of conjunctival and control tissues were stained with Alcian blue at pH 2.5 and 1.0 and counterstained with PAS. Non-goblet epithelial cell secretory vesicles contained neutral mucin, sialmucin, and sulphomucin. This study provides evidence for a 'second' mucus system of the conjunctiva, that this system is in the non-goblet epithelial cells, and that the mucus of this system has sulphomucins, sialomucins and neutral mucins.

Conjunctiva↗
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↗
PubMed1984

Nondestructive metabolic analysis of a cornea with the use of phosphorus nuclear magnetic resonance.

The viability of corneal donor material for penetrating keratoplasty depends on the metabolic status of the tissue; application of nondestructive nuclear magnetic resonance (NMR) techniques to the evaluation of donor tissue metabolism may provide information that would allow improved selection of donor material. The NMR spectrum generated from a single intact cornea permits qualitative and quantitative analysis of the following phosphatic metabolites: the sugar phosphates, inorganic orthophosphate, the alpha- and beta-phosphates of adenosine diphosphate and adenosine triphosphate, and the gamma-phosphate of adenosine triphosphate. Furthermore, the intracorneal pH (6.8) can be monitored from the resonance shift position of inorganic orthophosphate and can serve as an additional indicator of metabolic viability. To our knowledge, this study is the first to demonstrate the feasibility of the use of phosphorus NMR to monitor the metabolic status of a single intact cornea preserved in culture medium.

Adenosine Diphosphate↗
PubMed1984

Ex vivo metabolic analysis of eye bank corneas using phosphorus nuclear magnetic resonance.

Application of nondestructive and noninvasive nuclear magnetic resonance (NMR) techniques to the evaluation of corneal donor tissue metabolism may provide information that would allow improved selection of donor material for keratoplasty. A phosphorus 31 NMR spectrum was generated from a single intact human cornea, evaluating phosphatic metabolites qualitatively and quantitatively. The NMR analyses were conducted on four corneas (from patients aged from 73 to 75 years). Intracorneal pH (7.2) was monitored from the resonance shift position of inorganic orthophosphate (Pi). A numerical index (1.15) of tissue energy status was determined by comparing the relative tissue content of high-field, high-energy phosphate signals (adenosine triphosphate, adenosine diphosphate, nicotinamide-adenine dinucleotide, and the uridine diphospho-hexoses) to that of the low-field, low-energy phosphate signals (Pi, sugar phosphates, and phosphodiesters). This is the first demonstration of the feasibility of using nondestructive 31P NMR to monitor the metabolic status of a single intact eye bank cornea as would be required in the evaluation of eye bank tissue before keratoplastic procedures.

Adenosine Diphosphate↗
PubMed1984

Metabolic status of fresh v eye-bank-processed corneas. A phosphorus nuclear magnetic resonance study.

The concentrations of corneal phosphatic metabolites in fresh and eye-bank-processed corneas were measured by phosphorus 31 nuclear magnetic resonance of perchloric acid corneal extracts to determine whether metabolic differences exist between these two corneal preparations. Cat corneas were prepared using an eye-bank protocol, including specular microscopic examination and transport to a distant location. Fresh cat corneas were used as controls. The hexose 6-phosphate resonance band, the nucleoside monophosphate band, the phosphodiesters, and adenosine triphosphate of eye-bank-processed corneas were significantly decreased relative to fresh control corneas. Phosphatic metabolites that significantly increased relative to control corneas included inorganic orthophosphate and phosphocreatine. A calculated corneal tissue-energy index was significantly decreased for eye-bank-processed corneas relative to control. This decline demonstrates a compromise in the metabolic energy status of the tissue and is indicative of a diminished ability of the cornea to maintain its complement of high-energy phosphates.

Adenosine Triphosphate↗
PubMed1984

Mononuclear and IgA-containing cells in the lacrimal gland of germ-free and conventional rats.

Mononuclear cells in the lacrimal (exorbital) glands of five germ-free, five ex-germ-free, and five age-matched conventional rats were counted by light microscopy. Tissues from these rats were also examined by electron microscopy. IgA-containing plasma cells were counted by immunofluorescence microscopy in the lacrimal glands of five germ-free and five conventional rats. The median number (and range) of mononuclear cells per ten high-power fields was 25 (14-28) in germ-free rats, 33 (32-43) in ex-germ-free rats, and 41 (36-50) in conventional rats. The median number (and range) of IgA-containing plasma cells per ten high-power fields was two (0-5) in germ-free and 44 (29-72) in conventional rats. The differences in the numbers of mononuclear cells in the lacrimal glands of germ-free as compared with ex-germ-free and with conventional rats were statistically significant (P less than 0.004). The difference between the numbers of IgA-containing plasma cells in germ-free as compared with conventional rats was also statistically significant (P less than 0.004). Electron microscopy revealed that the mononuclear cells in all groups of rats consisted of macrophages and lymphocytes. These observations suggest that the number of mononuclear cells, and particularly IgA-containing plasma cells, in the rat lacrimal gland can be increased by systemic and/or local immunologic stimulation.

Animals↗