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J V Greiner

Publications and source records attributed to J V Greiner.

At least 37 records · Page 2Linked to original sources
PubMed1995

The effects of age on phosphatic metabolites of the human cornea.

Phosphatic metabolites from human corneas, pooled into 7 decades ranging from ages < 1 year through 79 years, were quantitated using phosphorus-31 magnetic resonance (31P MR) spectroscopy. Relative concentrations of phosphorus-containing compounds measured included the low-energy metabolites [phosphomonoesters (PME), inorganic orthophosphate (Pi), phosphodiesters (glycerol 3-phosphorylethanolamine and glycerol 3-phosphorylcholine)] and the high-energy metabolites [phosphocreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), nucleosidediphosphosugars and the dinucleotides]. Significant linear changes attributable to age occur in the relative mole percentage decrease of phosphate concentrations of human corneal PME, PCr and ATP, and in the increase of Pi. Age-attributable rates of decrease in PME at -0.162 MPP/YR (mole percent phosphorus per year), PCr at -0.015 MPP/YR and ATP at -0.487 MPP/YR combined, approximate the rate of increase in Pi determined to be +0.729 MPP/YR. Of the indices computed from the human corneal spectral data, the ratios of ATP/Pi and PME/Pi and the tissue energy modulus were all found to decrease significantly with age. These changes in corneal phosphatic metabolites are indicative of an overall decline in high-energy metabolism with age.

Adolescent↗
PubMed1994

The effect of hEGF and insulin on corneal metabolism during Optisol storage.

We examined the effect of the growth factors, human epidermal growth factor (hEGF) and insulin, on corneal metabolism during storage in Optisol, a chondroitin-sulfate-(CS)-based storage medium. Paired cat corneas, in either Optisol only or Optisol with growth factor(s), were analyzed using ex vivo 31P nuclear magnetic resonance, after storage for 1 week at 4 degrees C. Lysosomal enzyme release into the media at the end of the storage period also was measured fluorometrically. Both epithelial-intact and epithelial-denuded corneal pairs were examined for all conditions. Considering corneas having either intact epithelia or epithelium-denuded corneas, the addition of either growth factor alone to Optisol did not alter the relative corneal concentrations of five of the six phosphatic metabolite spectral bands measured or two metabolic ratios calculated from these bands. Phosphodiesters, however, were significantly lower in corneas stored in Optisol containing both hEGF and insulin (23%) than in corneas stored in Optisol alone (30%). Intracorneal pH was unaffected by the addition of growth factor(s). A significantly higher release of alpha-glucosidase and alpha-mannosidase was noted in those corneas stored in Optisol containing both hEGF and insulin. Optisol maintains high-energy phosphate corneal metabolism similar to other CS-based media, K-Sol and Chondroitin Sulfate Corneal Storage Medium (CSM). The addition of the growth factors hEGF and insulin to Optisol alters corneal metabolic activity during storage in a manner indicative of conserving corneal phospholipids.

Animals↗
PubMed1994

Tear film lipid layer thickness as a function of blinking.

Alterations in the tear film lipid layer as a function of blinking were investigated using a custom-designed specular reflection monitoring system. The tear film lipid layer of 104 subjects under conditions of normal ("baseline") blinking and "forceful" blinking was quantitated on the basis of specific interference colors. Deliberate, forceful blinking was found to significantly increase the lipid layer thickness (LLT) of the tear film. The magnitude of increase was found to be correlated with the baseline LLT values; individuals with baseline LLT values of 75-150 nm demonstrated a mean increase in LLT of 33 nm following forceful blinking, whereas subjects with baseline LLT values < or = 60 nm experienced a mean increase of 19 nm. The difference in the magnitude of increase between the groups was highly significant (p = 0.0001). The data suggest that, in addition to playing a role in the spreading of lipid across the tear film, the blinking mechanism may be important in the maintenance of the lipid layer by augmenting the expression of lipids from the meibomian glands.

Adolescent↗
PubMed1994

Phospholipid analysis of mammalian optic nerve tissue: a 31P nuclear magnetic resonance spectroscopic study.

Phospholipids of optic nerve (n = 30) from 5.6-kg rabbits were analyzed by 31P nuclear magnetic resonance (NMR) spectroscopy. Phospholipid metabolites detected were as follows (mol %): phosphatidylcholine (PC; 25.82 +/- 0.12), PC plasmalogen/alkylacyl PC (2.07 +/- 0.13), sphingosylphosphorycholine (1.12 +/- 0.20), phosphatidylinositol (PI; 2.17 +/- 0.21), lyso PC (0.85 +/- 0.06), sphingomyelin (12.52 +/- 0.10); phosphatidylserine (PS; 14.38 +/- 0.11), phosphatidylethanolamine (8.98 +/- 0.11), ethanolamine plasmalogen (28.99 +/- 0.30), unidentified phospholipid (1.10 +/- 0.01), phosphatidic acid (PA; 1.72 +/- 0.06), and lyso PS (0.28 +/- 0.10). The bulk of the ethanolamine phosphatide is in the form of its plasmalogen, which is the major phospholipid detected. The choline plasmalogen, or a reduced derivative thereof, also is present; thus, a significant phospholipid biosynthetic pathway for optic nerve tissue involves the plasmalogen route, which is a pathway distinct from the PA route responsible for the synthesis of PS, PI, and PC. This new 31P NMR lipid analytical technique offers potential for studying optic nerve phospholipid metabolism and degenerating optic nerve tissue, since the technique can accurately quantitate (1) both plasmalogen and nonplasmalogen phospholipids, (2) minor phospholipid components, and (3) previously undetected phospholipids.

Animals↗
PubMed1994

Distribution of membrane phospholipids in the crystalline lens.

PURPOSE: To determine the phospholipid content of specific anatomic regions within the crystalline lens. METHODS: Phospholipid extracts of tissues dissected from 5 sets of 10 rabbit lenses were analyzed by 31P nuclear magnetic resonance spectroscopy. Twenty-nine pathway-specific metabolic indexes were calculated from groups of phospholipids and ratios of phospholipids. RESULTS: Phospholipid levels (mole percent) were determined from the capsule with attached epithelium, the cortex, and the nucleus. Eleven phospholipids were detected with significant regional differences in the lens phospholipid profiles. The levels of phosphatidylcholine (PC), PC plasmalogen-alkylacyl PC, phosphatidylinositol (PI), phosphatidylethanolamine (PE), and diphosphatidylglycerol (DPG), and of the lyso derivatives (lyso PC and lyso PE) were greater in the capsule plus epithelium than in the cortex or the nucleus. Levels of sphingomyelin, phosphatidylserine, and PE plasmalogen (EPLAS) were less in the capsule plus epithelium than in the cortex or the nucleus. PC, PC plasmalogen-alkylacyl PC, EPLAS, and lyso PE had nearly equal amounts in the cortex and the nucleus. PI, lyso PC, and DPG could not be detected in the nucleus. DPG was only detected in the capsule plus epithelium. An unidentified phospholipid at 0.13 ppm was approximately equal in the cortex and the nucleus, but it could not be detected in the capsule plus epithelium. CONCLUSIONS: These differences demonstrate a significant heterogeneity among these anatomic regions of the lens, and differences in the nucleus relative to other regions studied are consistent with those in membranes that less readily undergo transitions from the relatively impermeable lamellar phase to the more permeable hexagonal HII phase.

Animals↗
PubMed1993

Metabolic compatibility of abattoir and human corneas: an ex vivo 31P nuclear magnetic resonance spectroscopic study of intact tissues.

This study establishes the metabolic similarities and differences of intact abattoir corneas and the human cornea ex vivo, using 31P nuclear magnetic resonance spectroscopy. Phosphorylated sugars (SP), inorganic orthophosphate (Pi), phosphodiesters, ATP, ADP, and the nucleoside diphosphosugars and dinucleotides (NS&DN) were quantitated. The intracorneal pH also was determined. In addition, metabolic indices ATP/Pi, ATP/ADP, ATP/(ADP + Pi), SP/Pi, the phosphorylation potential, and the 31P energy modulus were calculated. Significant differences were observed between the abattoir and human corneas in phosphorylated sugars, NS&DN, and intracorneal pH, as well as in the indices ATP/ADP and SP/Pi. The overall energy status as measured by the 31P energy modulus was significantly higher in the bovine cornea when compared to the porcine and human corneas, suggestive of a very high energy reserve in the bovine cornea.

Adenosine Diphosphate↗
PubMed1991

The effects of age on phosphatic metabolites of the human crystalline lens.

Paired human lenses ranging from 2 to 96 yr old (n = 17) were harvested within 2 hr post-mortem and immersed in liquid nitrogen. Phosphorus containing metabolites from perchloric acid extracts were quantitated using phosphorus-31 nuclear magnetic resonance spectroscopy. Low-energy metabolites detected include the phosphomonoesters (PME) hexose-6 phosphate, alpha-glycerol phosphate, fructose 1,6-diphosphate, beta-glycerol phosphate (beta-GP), uncharacterized phosphomonoesters at 4.63 delta, 4.34 delta and 3.05 delta, phosphorylethanolamine (PE), inosine and adenosine monophosphates, and phosphorylcholine (PC). Inorganic orthophosphate (Pi), glucose 1-phosphate and glycerol 3-phosphorylcholine were the other low-energy metabolites detected. High-energy metabolites phosphocreatine (PCr), adenosine tri- and di-phosphates (ATP, ADP), nucleoside diphosphorylsugars (NS) and the dinucleotides were also detected. The following metabolic indices were calculated: PCr/Pi, PME/Pi; ATP/Pi, PCr/ATP, ATP/ADP, PE + PC, PC/PE, energy charge, phosphorylation potential, and the energy modulus. A significant linear increase with age (P less than 0.05) occurred only in the uncharacterized resonance at 3.05 delta (r = 0.4593). Significant linear decreases with age (P less than 0.05) occurred in the uncharacterized resonance at 4.63 delta (r = -0.5950), beta-GP (r = -0.5018), PCr (r = -0.4495), N.S. (r = -0.4882). There was a significant (P less than 0.05) linear decrease in the energy modulus (ratio of high-energy to low-energy metabolites).

Adolescent↗
PubMed1991

Phosphatic intermediate metabolites of the porcine ocular tunica fibrosa.

This study compares porcine scleral and corneal phosphorylated intermediate metabolites determined using 31P NMR. These tissues comprise the tunica fibrosa (outer coat) of the eye. Since the sclera does not possess epithelia as does the cornea, comparative analysis of these tissues included examination of the cornea with and without its epithelia. The phosphorylated intermediates detected include: dihydroxyacetone phosphate, hexose 6-phosphates, alpha-glycerol phosphate, beta-glycerol phosphate, ethanolamine and choline phosphates, nucleoside mono-, di-, and tri-phosphates, inorganic orthophosphate, glycerol 3-phosphoryl-ethanolamine and -choline, phosphoglycans, phosphocreatine, nucleoside diphosphosugars, dinucleotides, and four uncharacterized (unknown) signals. Metabolic indices, comprised of individual or grouped metabolites, were calculated to further compare and contrast metabolites and to provide more pathway specific metabolic interrelations for phosphorylated metabolites. Significant differences exist between the corneal stroma and the sclera in 16 of the 22 phosphorylated metabolites determined, whereas differences exist between the whole cornea and the sclera in six of the 22 phosphorylated metabolites. Considering all metabolite levels and metabolic indices in aggregate, the sclera is most similar to the whole cornea and least similar to the corneal stroma.

Animals↗
PubMed1991

Comparative histogenesis of Bruch's membrane (complexus basalis).

We documented the comparative histogenesis and timing of development of Bruch's membrane (complexus basalis) in five mammalian models with different lengths of gestation. Retinas with attached choroid from the central posterior pole of the eye were obtained from hamster, vole, rabbit, ferret and cat, from mid-gestation onward until the time at which all components of Bruch's membrane could be detected. The sequence of events in the development of Bruch's membrane was similar among species, however the time of appearance of the components varied. At mid-gestation, the basement membrane of the retinal pigment epithelium (RPE) was present to some degree in all species and microfibrils were developing in the connective tissue space external to the RPE basement membrane. The appearance of an initially scant endothelial basement membrane around the choriocapillaries occurred on post-natal (P) day 1 (P1) in hamster, pre-natal (E) day 20 (E20) in vole, E16 in rabbit, P2 in ferret, and E48 in cat. Among the microfibrils within the connective tissue space external to the RPE, electron-dense islands presumed to be elastin were detected on P7 in hamster, P9 in vole, E24 in rabbit, P19 in ferret, and P1 in cat. Relative to birth date and eye opening, the components of Bruch's membrane in the ferret were detected at a later date than that of the other species studied. However, relative to the interval from conception to the appearance of the components of Bruch's membrane, the ferret and cat are similar, paralleling their similar intervals from conception to eye opening.

Animals↗
PubMed1991

Phosphatic metabolism and corneal edema.

From three groups of patients with corneal edema, the degree of edema was clinically quantified prior to penetrating keratoplasty. Corneas from patients with failed grafts (n = 16) had the greatest edema (mean score 3.8 +/- 0.6 SE), corneas with Fuchs' endothelial dystrophy (n = 12) had the least edema (1.4 +/- 0.4), and corneas with aphakic and pseudophakic bullous keratopathy (n = 40) had intermediate edema (2.7 +/- 0.5). Phosphorus-31 nuclear magnetic resonance spectroscopy was used to quantitate five high-energy phosphates and nine low-energy phosphates and calculate 12 metabolic indices from the specimens of these three edematous groups. Corneas with aphakic and pseudophakic bullous keratopathy had lower alpha-glycerophosphate (alpha-GP) and glycerol 3-phosphorylethanolamine and glycerol 3-phosphorylcholine (GPE & GPC), and higher phosphocreatine (PCr), adenosine diphosphate (ADP), monoesters/diesters, PCr/Pi (phosphocreatine/inorganic orthophosphate), and PCr/ATP (phosphocreatine/adenosine triphosphate) than corneas with Fuchs' endothelial dystrophy (p less than 0.05). Corneas from failed grafts had lower alpha-GP, ethanolamine phosphate (EP), ethanolamine phosphate and choline phosphate (EP&CP), monoesters/Pi, ATP/Pi, and energy modulus, no detectable GPE and GPC, and higher Pi, phosphorylglycans (PG), PCr, ADP, diesters, PCr/Pi, and PCr/ATP than those with Fuchs' endothelial dystrophy (p less than 0.05). Corneas from failed grafts had lower ATP, monoesters/Pi, ATP/Pi, PCr/Pi, and energy modulus and higher Pi, PG, ADP, diesters, and PCr/ATP than corneas with aphakic and pseudophakic bullous keratopathy (p less than 0.05). In summary, there was increasing decline in the high-energy metabolites and energy status with increasing edema.

Adenosine Triphosphate↗
PubMed1991

Comparison of phosphate metabolites of the ocular humors.

Ocular humors (aqueous humor and vitreous body) were obtained from porcine eyes. Perchloric acid extracts were prepared from aqueous and vitreous aspirates, and phosphorus-31 nuclear magnetic resonance spectroscopy 31P-NMR performed. Resonance signals from four high-energy phosphate groups (phosphocreatine, adenosine tri- and diphosphate and the dinucleotides) and nine low-energy phosphate groups [dihydroxyacetone phosphate, hexose-6-phosphate, alpha-glycerophosphate, fructose-1,6-diphosphate, ethanolamine phosphate, choline phosphate, inorganic orthophosphate (Pi), glycerol-3-phosphorylethanolamine and glycerol-3-phosphorylcholine] were present in the aqueous humor and/or vitreous body. Vitreous body phosphates significantly elevated relative to that of the aqueous humor were: DHAP, Hex 6-P, alpha-GP, Fru 1,6-diP, CP, GPE, PCr, ATP, ADP, and the dinucleotides; only Pi was significantly lower. Six metabolic indices (monoesters, diesters, monoesters/diesters, monoesters/Pi, ATP/Pi, energy modulus) were determined; all vitreous body indices were significantly higher than those of the aqueous humor. In particular, the energy modulus, a measure of overall metabolic energy status, was higher in the vitreous body (0.121 +/- 0.047) than in the aqueous humor (0.05 +/- 0.021).

Animals↗
PubMed1991

Human crystalline lens phospholipid analysis with age.

Paired human crystalline lenses (n = 21, patient ages 20-79 years) were extracted for lipids with chloroform-methanol 2:1, using the Folch method. The extracted crude lipids were analyzed at 202.4 MHz by phosphorus-31 magnetic resonance spectroscopy (31P NMR). Fourteen membrane phospholipids were detected including phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylcholine plasmalogen (PC plas), phosphatidylethanolamine (PE), phosphatidylethanolamine plasmalogen, lysophosphatidylethanolamine (PA), phosphatidylglycerol (PG), lysophosphatidylglycerol, phosphatidylserine (PS), phosphatidic acid, phosphatidylinositol, sphingomyelin (SPH), and two uncharacterized phospholipids. The uncharacterized phospholipid at 0.13 was the predominant phospholipid, comprising 43.20% of the lens phospholipid profile. A decrease in mole percent of phosphorus concentrations of PE, PC plas, and PC and an increase in SPH correlated with age. The following computed indices decreased with age: PC/PG and PE/PS; PC + PE; (PC + PC plas); and PC/PS. The following computed indices increased with age: (PC + SPH)/(PE + PS), SPH/PG, (PC + SPH)/(PE + PS), LPC/PC, LPE/PE, SPH/PE, and SPH/PC. Changes in membrane phospholipids of the crystalline lens with age as detected by 31P NMR can be used to fingerprint lens maturation.

Adult↗
PubMed1991

Membrane phospholipids of the ocular tunica fibrosa.

The authors compared porcine corneal and scleral membrane phospholipids determined with use of 31P nuclear magnetic resonance (NMR). These tissues make up the tunica fibrosa (outer coat) of the eye. Since the sclera, unlike the cornea, does not possess an epithelium or an endothelium, comparative analysis of these tissues included examination of the cornea with and without its epithelium and endothelium. The phospholipids quantified include: phosphatidylcholine, lysophosphatidylcholine, phosphatidylcholine plasmalogen, phosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylethanolamine plasmalogen, phosphatidylserine, sphingomyelin, phosphatidylinositol, phosphatidylglycerol, cardiolipin, and an uncharacterized phosphatide that accounts for 1.5%-3.5% of the detected phospholipids. Metabolic indices, comprised of individual or grouped metabolites, were calculated to further compare and contrast metabolites and to provide pathway-specific metabolic interrelations for each set of phospholipids from cornea and sclera. Significant differences exist between the corneal stroma and the sclera in 9 of the 12 phospholipids, whereas differences exist between the whole cornea and the sclera in 7 of the 12 phospholipids.

Animals↗
PubMed1990

Comparison of membrane phospholipids of the rabbit and pig crystalline lens.

Crystalline lenses excised from 5-7-month-old rabbits and pigs were extracted for lipids with chloroform/methanol, 2/1 using the Folch method. The extracted crude lipids were analyzed at 202 MHz by 31P-NMR spectroscopy. Twelve membrane phospholipids were detected. Both rabbit and pig phospholipid profiles contained phosphatidylcholine (PC), lysophosphatidylcholine, phosphatidylcholine plasmalogen, phosphatidylethanolamine (PE), phosphatidylethanolamine plasmalogen (PE plas), phosphatidylserine, sphingomyelin (SPH), and an uncharacterized phospholipid. In addition, pig lens profiles contained lysophosphatidylethanolamine, phosphatidylinositol, cardiolipin and phosphatidylglycerol. The data indicate that these two animal models have significant differences in membrane phospholipid profiles. In each species, however, the bulk phospholipid component resides in the neutral phospholipids PC, PE, PE plas, and SPH.

Animals↗
PubMed1990

Intralenticular water interactions with phosphates in the intact crystalline lens.

Since the ATP molecule is associated with the intracellular milieu, which consists mainly of water, this study suggests an intimate intracellular association with water molecules. Intact canine crystalline lenses (n = 6) were incubated at 37 degrees C in a buffer containing a pure D2O solvent and examined by [31P]-nuclear magnetic resonance (NMR) spectroscopy. Control lenses (n = 6) from contralateral eyes were incubated in a pure H2O-based buffer. During the first 4 h of a 24-hour incubation, the D2O-incubated lens maintained its phosphorus metabolic profile, indicating that the tissue maintains its metabolic health. During this period, however, the spectral signal widths of ATP narrowed progressively. Spectral-simulation analysis of ATP alpha-, beta- and gamma-phosphate signals revealed that the gamma-phosphate signal was narrowed significantly in contrast to the alpha-phosphate signal. Such differential signal narrowing within a single NMR spectrum indicates that the principal intracellular site of water hydrogen binding to the ATP molecule is at the gamma-group phosphate.

Adenosine Triphosphate↗
PubMed1989

Noninvasive metabolic analysis of eye bank corneas: a magnetic resonance spectroscopic study.

Nondestructive, noninvasive metabolic analysis of corneal donor tissue preserved in modified McCarey-Kaufman medium was achieved using phosphorus-31 magnetic resonance spectroscopy (31 P MRS). Clear corneas (n = 10) with minimal Descemet's folds and an endothelial cell density of 2990 +/- 166 cells/mm2 from donors aged 26 to 89 years were used. Relative amounts of low- and high-energy phosphatic metabolites were quantitated during a 1-h period using the integral of the 31P spectrum. The following indicators of the tissue's energy status were determined: (1) 31P spectral energy modulus (ratio of high- to low-energy metabolites, average 0.95 +/- 0.14); (2) adenosine triphosphate/inorganic orthophosphate (ATP/Pi) ratio, 1.97 +/- 0.55; (3) sugar phosphate/inorganic orthophosphate (SP/Pi) ratio, average 1.07 +/- 0.12; and (4) intracorneal pH, calculated from the resonance shift position of inorganic orthophosphate, average 7.28 +/- 0.05. The 31P MRS technique measures key corneal metabolic processes (maintenance of the high-energy phosphate complement, interrelationship of inorganic orthophosphate and its bioesters, and pH). This study provides baseline data for eventually determining optimal parameters of eye bank corneal tissues and for evaluating the metabolic status, or health, of the cornea.

Adenosine Triphosphate↗