Correlation of lipid layer thickness measurements with fluorescein tear film break-up time and Schirmer's test.

PURPOSE: This study correlates measurement of lipid layer thickness (LLT) with two frequently used dry eye tests, fluorescein break-up time (FBUT) and Schirmer's test with anaesthesia (STA). METHODS: Subjects (n = 44 eyes) with symptoms of dry eye and positive results for dry eye with either FBUT or STA or both were selected. Quantification of LLT was performed by the observation of colour interference patterns in zones of specular reflection using a custom-designed instrument. RESULTS: All correlations among pairs of tests were strong and exhibited a significance of P < 0.000: STA with FBUT, Pearson's correlation 0.653; STA with LLT, 0.764; FBUT with LLT, 0.751. When LLT was high, ie > or = 120 nm, which occurred in 14 eyes, STA was also elevated in those eyes and FBUT was high in 13 of the 14 eyes. When LLT was low, ie < or = 60, which occurred in 22 eyes, STA was below normal in 14 of the 22 eyes, and FBUT was below normal in 15 of the 22 eyes. These clinical observations paralleled the statistical findings computed from the entire data set. CONCLUSIONS: The correlations demonstrated in this study support the premise (1) that measurement of LLT is a reliable test for the diagnosis of dry eye, and (2) that aqueous deficiency and lipid deficiency, as they apply to dry eye disorders, are not mutually exclusive.

Cranial rhythmic impulse related to the Traube-Hering-Mayer oscillation: comparing laser-Doppler flowmetry and palpation.

The primary respiratory mechanism (PRM) as manifested by the cranial rhythmic impulse (CRI), a fundamental concept to cranial osteopathy, and the Traube-Hering-Mayer (THM) oscillation bear a striking resemblance to one another. Because of this, the authors developed a protocol to simultaneously measure both phenomena. Statistical comparisons demonstrated that the CRI is palpably concomitant with the low-frequency fluctuations of the THM oscillation as measured with the Transonic Systems BLF 21 Perfusion Monitor laser-Doppler flowmeter. This opens new potential explanations for the basic theoretical concepts of the physiologic mechanism of the PRM/CRI and cranial therapy. Comparison of the PRM/CRI with current understanding of the physiology of the THM oscillation is therefore warranted. Additionally, the recognition that these phenomena can be simultaneously monitored and recorded creates a new opportunity for further research into what is distinctive about the science and practice of osteopathic medicine.

Standardized medical record: a new outpatient osteopathic SOAP note form: validation of a standardized office form against physician's progress notes.

The accuracy and efficiency of recording information on a one-page standardized Outpatient Osteopathic SOAP Note Form (SNF) was compared with that obtained using the physician's progress notes (PPN). Use of the SNF in lieu of the PPN would assure the physician that proper clinical data were recorded to ensure proof of need and care in any instances of refused reimbursement. Moreover, standardized SNFs could be used to document and analyze present treatment protocols, enabling medical advances. Ten osteopathic physicians, who were skilled in osteopathic manipulative treatment (OMT), enrolled 300 patients. Initial and follow-up examinations totaled 959 visits (statistical cases); 76 statistical variables were compared. Essentially all information recorded in the PPN was recorded on the SNF. A significant difference (P < .05) was found between the PPN data set and the SNF data set in all but 17 of the 76 variables. Greater content of information almost always was found with the SNF data set. In addition, the SNF contained information not found in the PPN, most notably the severity and response to treatment of detected somatic dysfunctions. Participating physicians stated that the SNF takes about the same amount of time to fill in as the PPN. This makes the SNF a practical instrument for accurately and efficiently obtaining patient data in all physicians' offices. The validation study conducted demonstrated that the Outpatient Osteopathic SOAP Note Form easily and accurately reflected information recorded in the PPN and that data recorded may be used by physicians in their individual practices or for the conduct of osteopathic research.

Ex vivo phosphorus magnetic resonance spectroscopy on eye bank corneas and corneal metabolic health.

BACKGROUND: Since a potential exists for untoward effects on the cornea from the high magnetic fields and radio-frequency energies, and the further manipulation required for phosphorus-31 magnetic resonance spectroscopy (31P-MRS), we determined the effects of this technology on tissues using paired human corneas (n = 4) meeting criteria acceptable for transplantation. METHODS: Slit-lamp biomicroscopy, pachometry, specular microscopy, and redux fluorophotometry were performed on all corneas. One cornea of each pair was examined (< 30 min) by 31P-MRS. Following 31P-MRS, slit-lamp biomicroscopy, pachometry, and redox fluorophotometry were again performed. RESULTS: Data tabulated included the 31P energy modulus (1.37 +/- 0.28), the ATP/Pi (2.92 +/- 0.59) and SP/Pi (0.76 +/- 0.04) ratios, and the intracorneal pH (7.24 +/- 0.09). CONCLUSION: Since there were no significant differences in slit-lamp biomicroscopy, endothelial density and morphometry, cell counts, and pachometric and redox fluorophotometric measurements between corneas of each pair before and after 31P-MRS analysis, it was concluded that there was no detectable metabolic damage secondary to such analysis. This study suggests that MRS analysis of human eye-bank tissues does not damage the cornea metabolically and may provide a practical evaluation of the health of the cornea at the biochemical level.

Comparing psychotic and affective disorders by musculoskeletal structural examination.

Groups of hospitalized patients with psychotic and affective disorders (N = 60) underwent musculoskeletal structural examination. Psychotic and affective disorders each tend to affect a different portion of the musculoskeletal system, with psychotic patients exhibiting increased musculoskeletal dysfunction in the lower extremities and affective-disorders patients exhibiting increased cervical and thoracic dysfunction. At the clinical level, the structural examination may be used to correlate psychiatric disorders with dysfunctional regions of the musculoskeletal system.

Phospholipids in meibomian gland secretion.

The bulk of the lipid layer overlying the aqueous portion of the precorneal tear film is composed of polar and nonpolar components. The nonpolar lipids have been the subject of numerous studies; however, the polar lipids have remained relatively uncharacterized. The polar lipids are thought to contain surfactant phospholipids that are critical to the spreading of a lipid film over the aqueous layer, by providing an interface between this layer and the nonpolar lipids. The purpose of the present study is to identify and quantitate the phospholipid complement of meibomian gland secretion which provides the tear film with phospholipids. Meibomian gland secretion was collected from rabbits and phospholipids identified and quantitated by 31P nuclear magnetic resonance spectroscopy. Ten phospholipids were detected from meibomian gland secretion: diphosphatidylglycerol, dihydrosphingomyelin, ethanolamine plasmalogen, phosphatidylethanolamine (PE), phosphatidylserine, sphingomyelin, lysophosphatidylcholine, phosphatidylinositol, alkylacylphosphatidylcholine, and phosphatidylcholine (PC). The two major phospholipids were PC and PE, together comprising nearly 60% of the total phospholipid profile. The nature and relative concentrations of the meibomian gland secretion phospholipids are congruous with a surfactant role at the aqueous-lipid interface and, considering the physical chemistry of the tear film, suggest that the phospholipids should be organized in a very flat or planar configuration.

Interspecies comparisons of lens phospholipids.

The purpose of this study was to compare and contrast quantitative crystalline lens phospholipid profiles among human, pig, rabbit, rat mouse, dog, lamb, guinea pig, beef, calf, chinook salmon, and golden roach. Lenses were extracted using chloroform-methanol. The extracts were prepared for phospholipid 31P NMR quantitative analysis using an NMR analytical reagent specifically designed for this purpose. Lens phospholipid profiles vary among vertebrate species. Thirteen different phospholipids [phosphatidylglycerol, lysophosphatidylethanolamine, phosphatidic acid, diphosphatidylglycerol, the ethanolamine plasmalogen (EPLAS), phosphatidylethanolamine (PE), phosphatidylserine (PS), sphingomyelin (SM), lysophosphatidylcholine, phosphatidylcholine (PC), including four uncharacterized (unknown) phospholipids at 1.31 ppm (human), 1.20 ppm (human, rabbit, dog, lamb, beef, calf), 0.13 ppm (all except rat), and -0.17 ppm (rat, beef) were detected. EPLAS, PE, PS, SM, and PC are the major lens phospholipids in all species except the human, where the major phospholipid is the unknown at 0.13 ppm. The lens content of this major unknown in mole percentage of the total detected phospholipid profile is: human 43.7; pig 6.7; rabbit, 6.1; rat (not detected); mouse, 3.2; dog, 5.0; guinea pig, 2.0; lamb, 7.0; beef, 7.7; calf, 5.6; chinook salmon, 6.7; and golden roach, 1.6. Large qualitative and quantitative differences were observed among lens species, indicating the necessity for prudent selection of appropriate animal models. The most striking finding is that no other species except the human species exhibits such a profound amount of the unknown phospholipid at 0.13 ppm. In the human lens, this phospholipid is the major phospholipid.

31P NMR phospholipid characterization of intracranial tumors.

Phospholipid extracts from 48 intracranial tumors were analyzed using 31P NMR. Phospholipids commonly identified in the tumor spectra included phosphatidylglycerol (PG), phosphatidic acid (PA), diphosphatidylglycerol (DPG), uncharacterized phospholipid (U), ethanolamine plasmalogen (EPLAS), phosphatidylethanolamine (PE), phosphatidylserine (PS), sphingomyelin (SM), lysophosphatidylcholine (LPC), phosphatidylinositol (PI), a choline phospholipid (CPLIP), and phosphatidylcholine (PC). Differences in the mean relative mole-percentage of phosphorus concentrations of individual phospholipids were used to differentiate among tumors. Neural sheath tumors (neurilemmoma, neurofibroma and fibrosarcoma) were noted to contain significantly elevated levels of SM relative to tumors of neural glial origin and individually, glioblastoma multiforme was noted to contain depressed levels of SM relative to neurilemmoma, neurofibroma and meningioma. Significantly decreased levels of PA were noted for glioblastoma relative to neurilemmoma along with significantly decreased levels of PE relative to meningioma. Elevated levels of LPC and CPLIP were seen in glioblastoma multiforme relative to meningioma. Additional findings included elevated levels of PC for glioblastoma multiforme relative to neurofibroma, and neurilemmoma was differentiated from neurofibroma with elevated levels of PA and depressed levels of PI. 31P NMR phospholipid analysis provides supplemental biochemical information which may be used to improve the interpretation of spectra acquired in vivo, and reveals important tumor-specific biochemical information which may further improve the understanding of the biological behavior of intracranial tumors.

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.

Meningioma phospholipid profiles measured by 31P nuclear magnetic resonance spectroscopy.

Fourteen cases of intracranial meningioma were characterized after chloroform/methanol extraction by 31P nuclear magnetic resonance (NMR) spectroscopy at 202.4 MHz. Each phospholipid class detected in the extracts was identified and quantitated in terms of its molar percentage relative to the total phospholipids measured. The following phospholipids were assayed by 31P NMR: phosphatidylglycerol, phosphatidic acid, diphosphatidylglycerol, ethanolamine plasmalogen, phosphatidylethanolamine (PE), lysophosphatidylinositol, phosphatidylserine, sphingomyelin, lysophosphatidylcholine (LPC), phosphatidylinositol (PI), sphingosylphosphorylcholine and phosphatidylcholine. In addition, two unidentified phospholipids were detected with resonances at 0.13 and -0.78 ppm, respectively. Three distinct types of spectra were obtained on the extracts and grouped accordingly for comparison purposes. Type 1 tumors showed unusual 31P NMR profiles with low levels of PE and PI and elevated levels of LPC; type 2 tumors were characterized by low levels of the ethanolamine phospholipids and near equivalent levels of PI and LPC. The spectra of type 1 and type 2 tumors were characteristic of degenerative cells that lacked membrane permeability associated with loss of ethanolamine plasmalogen in the presence of significant phospholipid turnover. Meningiomas belonging to the third spectral type showed characteristics similar to those of normal tissues with normal levels of PE and ethanolamine plasmalogen, as well as very low levels of LPC relative to PI. Type 3 tumors lacked the characteristic signs of degeneration noted in type 1 and type 2 tumors. The data corroborate and augment in vivo spectroscopic findings reported earlier and demonstrate the value of 31P NMR spectroscopic phospholipid analysis on lipid extracts for the characterization of meningiomas.

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).

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

Phospholipids from malignant, benign and noninvolved human breast tissues were extracted by chloroform-methanol (2:1) and analysed by 31P MR spectroscopy at 202.4 MHz. Thirteen phospholipids were identified as constituents of the profiles obtained among the 55 tissue specimens analysed. Observed patterns in phospholipid tissues profiles were distinct, allowing qualitative characterisation of the three tissue groups. Multivariate analysis of lysophosphatidylcholine (LPC) and an uncharacterised phospholipid were shown to be independently significant in predicting benign tissue histology as either fibrocystic disease or fibroadenoma in 92% of cases. Univariate analysis of relative mole-percentage of phosphorus concentrations of individual phospholipids using the Scheffé comparison procedure revealed that in malignant tissues, phosphatidylethanolamine was significantly elevated compared to benign (+ 32%) and noninvolved tissues (+ 22%). Phosphatidylinositol (+ 33%) and phosphatidylcholine plasmalogen (PC plas) (+ 25%) were increased in malignant compared to benign and LPC was decreased (-44%) in malignant compared to noninvolved. LPC was significantly depressed (-39%) in benign tissue compared to normal. Phospholipid indices computed to further characterise the three tissue groups showed PC plas/PC elevated in malignant tissue compared to benign and PE plas/PE depressed in malignant tissue compared to noninvolved. These findings support previous investigations reporting that the alkyl-phospholipid analogues of phosphatidylcholine are released by malignant tissues and that levels of ethanolamine are elevated in malignant tissues. Indices describing the choline-containing phospholipids showed that these lipids are depressed significantly in malignant tissue relative to healthy tissue.

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).

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.

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.

Phosphorus nuclear magnetic resonance and ocular metabolism.

Phosphorus (31P) nuclear magnetic resonance (NMR) represents a noninvasive technique for the assessment of ocular metabolism. The measurement of a spectrum of phosphorus-containing metabolites (e.g., phosphorylated sugars and ATP), including a number of heretofore uncharacterized metabolites, can be made with a single analysis. In addition to quantitating phosphatic metabolites, 31P NMR can be employed to monitor (1) the rate of metabolic change in a specific biochemical reaction via T1 and T2 relaxation times, and (2) the rate of change in the concentration of a particular metabolite. Several calculations indicating tissue energy status (health) can be made using quantitative spectroscopic information including: the phosphorylation potential, the energy charge of the adenylate system, and the 31P spectral modulus. Tissue pH can be determined as a function of shift in 31P NMR signals. 31P NMR techniques have both research and diagnostic applications in ophthalmology since potentially it provides a noninvasive method to analyze ocular tissues metabolically and detect subtle biochemical changes that precede overt manifestation of disease states. Such detection may allow for early and more effective therapeutic intervention of disease. Furthermore, the noninvasive quality of NMR spectroscopy will permit continual evaluation of therapy.

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.

Calcium-dependent effects of cadmium on energy metabolism and function of perfused rat heart.

Postequilibrated isolated rat hearts were perfused for 60 min with a standard supporting electrolyte buffer containing one of the following calcium concentrations: 0.9, 1.8, 3.5, or 5.0 mM, either with or without added cadmium. Doses of cadmium which proved to be minimally (0.03 microM Cd)--and maximally (3.0 microM Cd)--effective at 0.9 mM Ca were studied at all other calcium concentrations. A dose-dependent positive inotropy that persisted throughout the 60-min perfusion period was induced by the graded increases in the perfusate calcium concentration throughout the range from 0.9 to 5.0 mM. Atrioventricular node conductivity was prolonged significantly in hearts perfused with 0.9 mM Ca as compared to hearts perfused with higher calcium concentrations. Increasing the perfusate calcium concentration caused a dose-dependent increase in heart glycerol 3-phosphorylcholine (GPC) content. The other measured phosphatic metabolites of the heart were not altered significantly by varying the perfusate calcium level. In contrast, cadmium (3.0 microM Cd) induced extensive functional and metabolic aberrations which varied in magnitude as an inverse function of the perfusate calcium concentration. Contractile tension, rate of tension development (dT/dt), heart rate, coronary flow rate, and atrioventricular node conductivity were decreased significantly in response to cadmium perfusion. Moreover, these hearts characteristically had significantly elevated low energy phosphate (inosine monophosphate and inorganic phosphate) and decreased high energy phosphate (ATP, PCr) levels relative to their respective calcium controls. Furthermore, various phosphorylated intermediates of glycolysis (glucose 6-phosphate, fructose 6-phosphate, glucose 1-phosphate), as well as glycerol 3-phosphate, and uridine diphosphoglucose accumulated significantly in hearts perfused with cadmium at certain calcium concentrations below 5.0 mM. The calcium-activated increase in heart GPC was inhibited completely by 3 microM cadmium. At the minimally effective dose of cadmium (0.03 microM), demonstrable changes were apparent only at the lowest perfusate calcium concentration examined (0.9 mM). These findings are consistent with the hypothesis that cadmium interferes with calcium-activated and calcium-mediated physiologic and biochemical processes of the mammalian heart. The primary mechanistic basis for the action of cadmium appears to be linked to a competition with calcium for membrane and possibly intracellular binding and activation sites.

P-31 nuclear magnetic resonance analysis of brain: normoxic and anoxic brain slices.

Perchloric acid extracts were prepared from liquid-N2-frozen gerbil and guinea pig brain slices studied under one of three conditions: O2-incubated, N2-incubated or O2-incubated recovery following N2 incubation. Mole percentages of the various phosphatic components contained in the extracts were determined by phosphorus-31 nuclear magnetic resonance spectroscopy. The brain slice extract spectrum revealed a previously unreported group of brain phosphodiesters at -0.73 delta relative to 85% orthophosphoric acid. Although the phosphatic profiles from O2-incubated slices from gerbils and guinea pigs revealed only minor species variations, which differed quantitatively rather than qualitatively, species-specific differences were made readily apparent and amplified by incubating brain slices under oxygen-deficient conditions. Despite these differences which were most prevalent during the recovery phase, the overall metabolic changes described herein in response to N2-incubation were in accord with the results obtained by other analytical techniques. Inorganic orthophosphate (2.63 delta) was increased, while nucleoside (principally, adenosine) triphosphate (alpha-, -10.92 delta, beta-, -21.45 delta, and gamma-, -5.80 delta) and phosphocreatine (-3.12 delta) levels were decreased in response to N2 incubation. In addition, inosine monophosphate (3.78 delta) was increased and the levels of a partially characterized acid-labile phosphate (0.85 delta, guinea pig) were decreased upon N2 incubation. Phosphoglyceride metabolism also appeared to be altered by oxygen deprivation (gerbil). These latter findings provide additional information concerning the metabolic responses of cerebral tissue to oxygen deficient conditions.

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.