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PubMed2001

Induced myeloperoxidase activity and related superoxide inhibition during hormone replacement therapy.

OBJECTIVE: To test whether the menopause entails any changes in the myeloperoxidase activity of neutrophil granulocytes. The effects of hormone replacement therapy on myeloperoxidase activity and related changes in free radical production were also investigated. DESIGN: Laboratory investigation of the effect of oestrogen on intracellular myeloperoxidase activity and release from human neutrophil granulocytes. Analysis of related changes in superoxide anion generation. SETTING: 2nd Department of Medicine and 1st Department of Obstetrics and Gynaecology, Semmelweis University, Budapest. SAMPLES: Intracellular myeloperoxidase activity (mean peroxidase index) was measured automatically in blood samples obtained for general laboratory work-up from 135 randomly selected patients in our department. Blood samples from 11 postmenopausal women were analysed before and during hormone replacement therapy. Blood samples from 20 healthy volunteers were obtained and neutrophil granulocytes separated for in vitro measurement of superoxide anion production after adding myeloperoxidase to the incubation media. METHODS: The mean peroxidase index was measured using a Technicon H-3 instrument. myeloperoxidase release from neutrophils was quantified by ELISA technique. Superoxide production of isolated neutrophil granulocytes was measured by photometry. MAIN OUTCOME MEASURES: Intracellular activity of myeloperoxidase, concentration of myeloperoxidase-protein in supernatant of neutrophils, release of superoxide anion from neutrophil granulocytes. RESULTS: 1. Intracellular myeloperoxidase activity in neutrophils was lower in postmenopausal women, than in females with regular cycles (-1.84 +/- 3.06 versus 1.59 +/- 3.55, P < 0,001). 2. In postmenopausal women intracellular myeloperoxidase activity and myeloperoxidase release increased during hormone replacement therapy (-5.54 +/- 6.63 versus -0.2 +/- 6.05; P < 0.001 and 52.74 mU/ml +/- 25.73 versus 251.4 +/-234.1 mU/ml; P < 0.05). 3. Adding myeloperoxidase to neutrophil granulocyte suspensions, the production of superoxide anion fell (e.g. adding 280 ng/ml myeloperoxidase: 77.9 +/- 14.04 % of control production, P < 0.001). CONCLUSION: Hormone replacement restores the reduced myeloperoxidase activity in menopausal women. Adding myeloperoxidase to neutrophil granulocytes, the production of free radicals decreases.

Adult↗
PubMed2004

Macular pigment optical density in young Chinese adults.

PURPOSE: The purpose of this study was to determine the macular pigment optical density (MPOD) in a group of Chinese subjects using a simple customized light emitting diode-based device. METHODS: Heterochromatic flicker photometry was used in this study. With a 1 degrees diameter circular test stimulus, MPOD was estimated by comparing the relative sensitivities to a blue light, against a green reference, between foveal and parafoveal 4 degrees temporal locations. Fixed alternating frequencies were used. Repeatability was determined on a small group of subjects. A further group of 67 young healthy subjects provided data for MPOD norms. RESULTS: All results were corrected to the common MPOD reference wavelength of 460 nm. The group-averaged MPOD was 0.48 (S.D. 0.23). We found no gender difference in MPOD. The coefficient of variability was 7.2-8.0% and the coefficient of repeatability was 0.12. CONCLUSIONS: The MPOD of Chinese subjects did not differ greatly from the reported MPOD in white subjects.

Adolescent↗
PubMed1998

Engineering the luxCDABE genes from Photorhabdus luminescens to provide a bioluminescent reporter for constitutive and promoter probe plasmids and mini-Tn5 constructs.

The luxCDABE operon of Photorhabdus luminescens has been cloned and engineered as an easily mobilisable cassette flanked by sites for commonly used restriction enzymes. Constitutive and promoter probe plasmids utilising the P. luminescens luxCDABE have been constructed using a number of compatible replicons and antibiotic markers. Complementary to these plasmids, a range of promoterless and constitutive luxCDABE mini-Tn5 derivatives has been constructed. The potential of coupling mini-Tn5 luxCDABE promoter probe transposons with automated luminometry and photometry to screen for mutants that exhibit growth phase variation in gene expression is demonstrated.

Cloning, Molecular↗
PubMed1999

Angiotensin-II increases cytoplasmic calcium, cell number and total DNA for human periodontal ligamental cells in vitro.

The identification and the development of potential growth factors for the cells of the periodontal ligament is an important and novel stratagem for the regeneration of tissue destroyed by periodontal pathogens. The problem is that growth factors are difficult to synthesize, very immunogenic and expensive. The purpose of our study was to determine if angiotensin-II, a naturally occurring octo-peptide with growth-factor like properties in cardiac muscle, could also stimulate cultured human periodontal ligament cells. If angiotensin-II does have growth factor properties, then it should be able to increase cytoplasmic calcium (a secondary messenger associated with mitogenesis) and to increase fibroblast proliferation. Fura-2 fluorescence and aequorin photometry were used to follow changes in cytoplasmic calcium. Cytometry and total amount of DNA were used to measure proliferation evoked by angiotensin-II. We found that angiotensin-II increased cytoplasmic calcium, the total amount of DNA and cell number, suggesting that angiotensin-II has mitogenic properties for cells isolated from human periodontal ligament.

Aequorin↗
PubMed1977

Kinetics of the binding of salicylazosulfapyridine to human serum albumin.

In order to elucidate the possibility of the dissociation rate of drugs from plasma proteins presenting a rate limiting step in the elimination of drugs by secretion (renal or biliary) and metabolism, the kinetics of salicylazosulfapyridine (SASP) binding to human serum albumin (HSA) has been investigated by stopped-flow photometry. Equilibrium dialysis showed that HSA has three classes of binding sites for SASP with 0.93, 2.3 and 8.4 sites, respectively, and association constants of 2.1.10(6), 1.4.10(5) and 3.0.10(3) M-1, respectively. The association rate constants for the first and second classes are 4.4.10(6) and 1.5.10(7) M-1 sec.-1, and the dissociation rate constants are 2.1 and 109 sec.-1. At SASP concentrations resulting from the usual therapeutic doses about 83% will bind to the first class binding sites. The dissociation "half time" for this class being 0.34 sec., leads to the conclusion that dissociation rates of this order of magnitude are unlikely to reduce the rate of metabolism or biliary secretion whereas it may reduce renal tubular secretion. Whether this is the case depends on the intrinsic rate constant of secretion.

Half-Life↗
PubMed1997

Comparison of two methods of measurement of whole blood glucose in the neonatal period.

The purpose of this study was to compare the performance and accuracy of the HemoCue B-Glucose photometer system and reagent strip tests used in conjunction with reflectance photometry against a reference plasma glucose method. One hundred consecutive babies admitted to the neonatal unit over a 6-month period were enrolled in the study. Each baby had a heelprick capillary glucose measured by HemoCue and reagent strip tests. At the same time venous plasma glucose and haematocrit were measured. The mean difference between the reagent strip test and plasma glucose was significantly less than the corresponding value for the HemoCue (0.015 +/- 1.41 vs 0.837 +/- 1.565 mmol l-1, mean +/- SD); however, the agreement limits between both methods and plasma glucose were wide. No significant effect of haematocrit was detected on either method. The HemoCue photometer does not offer any advantage over the widely used reagent strip tests in the neonatal period. However, the limits of agreement of both methods compared with plasma glucose are too wide to be clinically acceptable in the neonatal period.

Blood Glucose↗
PubMed1974

Changes of intracellular sodium and potassium ion concentrations in isolated rat superior cervical ganglia induced by depolarizing agents.

1. Na and K contents of isolated rat superior cervical ganglia were measured by flame photometry, and intracellular Na and K concentrations ([Na](i) and [K](i)) calculated using Li and (35)SO(4) to determine extracellular space (e.c.s.).2. Resting concentrations after 1-2 hr incubation at 25 degrees C in normal Krebs solution were: [Na](i), 19.8 +/- 0.9 m-mole (kg cell water)(-1); [K](i), 192.7 +/- 2.8 m-mole (kg cell water)(-1) (mean +/- S.E. of mean of thirty-five ganglia). Correction for losses during e.c.s. measurement gave 22 mM [Na](i) and 207 mM [K](i) as probable fresh concentrations.3. Carbachol (180 muM for 4 min) increased [Na](i) by 47.8 +/- 2.9 m-mole (kg cell water)(-1) and decreased [K](i) by 54.6 +/- 4.3 m-mole (kg cell water)(-1). Maximal exchange with carbachol or nicotine (at approximately 1 mM for 4 min) amounted to 80-100 m-mole (kg cell water)(-1). On washing with Krebs solution containing 2.5 mM hexamethonium recovery of ionic concentrations occurred with a rate constant of 0.3-0.4 min(-1).4. Restitution of ganglionic Na and K after carbachol was inhibited by washing with K-free solution, and slowed by ouabain (0.14 mM), cyanide (2 mM) or cooling (Q(10) 2.7 between 17 and 27 degrees C).5. Equilibrium potentials for Na and K (E(Na), E(K)) at rest were calculated to be +49 and -88 mV. At a membrane potential (E(m)) of -70 mV, the permeability ratio P(Na):P(K) was calculated at 0.04:1 (assuming P(Cl):P(K) < 0.1).

Animals↗
PubMedDate not supplied

Noninvasive detection of macular pigments in the human eye.

There is currently strong interest in developing noninvasive technologies for the detection of macular carotenoid pigments in the human eye. These pigments, consisting of lutein and zeaxanthin, are taken up from the diet and are thought to play an important role in the prevention of age-related macular degeneration, the leading cause of blindness in the elderly in the Western world. It may be possible to prevent or delay the onset of this debilitating disease with suitable dietary intervention strategies. We review the most commonly used detection techniques based on heterochromatic flicker photometry, fundus reflectometry, and autofluorescense techniques and put them in perspective with recently developed more molecule-specific Raman detection methods.

Carotenoids↗
PubMedDate not supplied

Fast assessment of the central macular pigment density with natural pupil using the macular pigment reflectometer.

We built a new macular pigment reflectometer (MPR) for fast and objective measuring of the optical density of macular pigment in the human eye, using the undilated eye. The design is based on the spectral reflectance from a spot of white light at the fovea. To evaluate its performance, we measured the macular pigment of 20 healthy subjects, ages 18 to 79 years, under four conditions: (1) natural pupil in the dark, (2) natural pupil with dim room light, (3) dilated pupil in the dark, and for comparison with a different technique, (4) heterochromatic flicker photometry (HFP) in dim room light with natural pupil. Condition 1 was repeated in a subset of 10 subjects after an interval of at least 3 days. Data analysis with a model of reflectors and absorbers in the eye provided the density of the macular pigment in conditions 1 to 3. Dim room light and pupil dilatation had no influence on measured density. Mean within subjects variation was typically 7%. Mean difference between test and retest after at least 3 days was 1%. Correlation between MPR and HFP was r=0.56 (p=0.012). Mean within subjects variation with HFP was 19%. The new instrument holds promise for specific applications such as epidemiological research.

Computer Systems↗
PubMed1967

Permeability properties of Rickettsia mooseri.

The passive permeability properties of Rickettsia mooseri to both inorganic and organic solutes have been examined. Visual observations by phase-contrast microscopy of rickettsiae in macerated yolk sacs taken directly from heavily infected eggs revealed plasmolysis with hypertonic NaCl and KCl as well as with sucrose solutions. In contrast, similar visual studies of rickettsiae which had been subjected to freezing or to a purification process, or both, were plasmolyzed by hypertonic sucrose but not by hypertonic NaCl and KCl. These primary observations were extended to a variety of solutes and were placed on a quantitative basis by use of optical density and radioisotope dilution methods. Intracellular Na(+) and K(+) concentrations in processed rickettsiae, measured by flame photometry, closely paralleled the concentration of these ions in the suspending medium. It was concluded that R. mooseri appears to possess an osmotically active, functional, and structural membrane distinct from the cell wall, located at the surface of a structure analogous to the bacterial protoplast. In the intact organism, this membrane is passively impermeable to sucrose, NaCl, and KCl. However, altered permeability properties, especially to inorganic electrolytes, may be expected in rickettsiae which have been stored in the frozen state and subjected to a lengthy purification process.

Animals↗
PubMed1994

Changes in anterior chamber flare and cells following cataract surgery.

The laser flare cell meter allows rapid non-invasive quantification of aqueous flare and cells. In this prospective study laser photometry was used to document the recovery of the blood-aqueous barrier in 27 normal eyes following cataract surgery. Aqueous flare and cells were highest on the first postoperative day, declining rapidly in the first week and returning to preoperative levels by 3 months. In six eyes (22.2%) there was an increase in either flare and cells or flare alone during the first postoperative week which was associated with a delayed recovery of the blood-aqueous barrier for up to 1 month following surgery. A consensual flare response was found to occur in the fellow eye in five patients (18.5%).

Aged↗
PubMed1995

Study of the blood-aqueous barrier in choroidal melanoma.

AIMS: Aqueous flare was used to determine the frequency and amount of blood-aqueous barrier breakdown and correlate it with tumour variables. METHODS: Aqueous flare was analysed prospectively by laser flare photometry in 139 consecutive patients seen in the oncology unit for choroidal melanoma. Both eyes of patients were examined with a laser flare cell meter in a standard fashion. RESULTS: Mean flare difference between healthy and tumour eyes was 3.01 (SD 2.5) photons per millisecond (ph/ms) in 32 cases of small melanomas (p < 0.0001), 10.74 (13.9) ph/ms in 92 cases of medium and large melanomas (p < 0.0001), and 19.23 (11.8) ph/ms in 15 cases of very large melanomas (p < 0.0001). This mean differential flare was significantly higher in medium and large than in small melanomas (p < 0.002) and in very large melanomas than in medium and large melanomas (p < 0.028). A difference of > or = 7 ph/ms between affected and healthy eyes was noted in 70 of 139 melanomas (50.4%). It was found in 3/32 small melanomas (9.4%), in 53/92 medium and large melanomas (57.6%), and in 14/15 very large melanomas (93.3%). CONCLUSION: Multiple linear regression analysis showed that flare was most strongly correlated with tumour volume (r = 0.43; p < 0.0001) and tumour height (r = 0.41; p < 0.0008).

Aqueous Humor↗
PubMed1997

Relation between postoperative blood-aqueous barrier damage and LOCS III cataract gradings following routine phacoemulsification surgery.

AIM: To examine the relation between cataract density, the phacoemulsification energy required for its removal, and blood-aqueous barrier (BAB) damage on the first day after surgery. METHODS: A prospective study recruiting patients with normal eyes apart from senile cataract. Preoperatively, visual acuity, anterior chamber laser flare, and cell values were measured using the Kowa laser flare meter, and the LOCS III grading of the cataract defined. The patients all underwent standardised phacoemulsification surgery through a superior scleral tunnel incision, with confirmed in the bag placement of a one piece PMMA IOL; all surgical complications were excluded. The phaco power delivered was recorded as the cumulative delivered energy, CDE. On day 1 visual acuity and laser flare and cell readings were taken. RESULTS: 101 patients were recruited and all completed the protocol. Older patients had a higher preoperative flare value (p = 0.003); preoperative cell values were significantly related to nuclear opacity (p = 0.021) and colour (p = 0.011). Postoperative flare was related to preoperative flare (p = 0.001) and nuclear colour (p = 0.038). CDE was related to nuclear colour (p = 0.031) and opacity (p = 0.022), but not to aqueous flare. CONCLUSIONS: Damage to BAB after routine phacoemulsification surgery is predicted by the preoperative flare values and the density of the cataract nucleus. The amount of phacoemulsification energy required to remove a cataractous lens is related to the density of the cataract but affects postoperative flare to a minimal degree. Other factors such as surgical technique are probably more important. Laser photometry is a useful tool for objectively assessing surgical technique.

Blood-Aqueous Barrier↗
PubMed2002

Effects of dexamethasone, diclofenac, or placebo on the inflammatory response after cataract surgery.

AIM: To compare the inflammatory response after phacoemulsification and intraocular lens (IOL) implantation using postoperative treatment with dexamethasone, diclofenac, or placebo. METHODS: A prospective, randomised, controlled double masked study including 180 patients enrolled for cataract surgery. The patients were 64-85 years old and had no eye disease other than cataract. After phacoemulsification and IOL implantation the patients were randomised to topical treatment with dexamethasone phosphate 0.1% (group I), diclofenac sodium 0.1% (group II), or placebo (saline 0.9%) (group III). The drops were administered four times daily during the first week and twice daily during the second, third, and fourth weeks. The inflammatory reaction in the anterior chamber was measured with laser flare photometry preoperatively and 1, 3, and 8 days, 2 and 4 weeks, 2 and 6 months, and 1, 2, and 4 years postoperatively. Inflammatory symptoms were registered. Biomicroscopy and visual acuity determinations were performed. The rate of Nd:YAG laser posterior capsulotomies after 2 and 4 years was determined. RESULTS: After 3 and 8 days (p <0.0001), 2 weeks (p <0.0001), and 1 month (p = 0.0013) median flare was highest in group III. There were no significant differences between group I and II. Inflammatory symptoms and striate keratopathy were more common in group III. CONCLUSION: Dexamethasone and diclofenac were equally effective in reducing postoperative inflammation after phacoemulsification and IOL implantation in eyes with no other disease than cataract. Both substances were more effective than placebo.

Aged↗
PubMed1966

Factors determining the aggregation of urinary mucoprotein.

The factors determining aggregation of Tamm-Horsfall urinary mucoprotein have been examined using the technique of light-scattering photometry, which has allowed the study to be performed at the concentrations of the mucoprotein in which it occurs in the urine in vivo. The tendency to formation of aggregates is enhanced by increases in concentration of the mucoprotein, by increases in electrolyte concentration within physiological limits, and by lowering of the pH within the physiological range. The effects of 1:2 and 2:1 electrolytes are somewhat different from those of 1:1 electrolytes. The data suggest that the isoelectric point of Tamm-Horsfall protein is higher than previously thought.

Electrolytes↗
PubMed1991

23Na and flame photometric studies of the NMR visibility of sodium in rat muscle.

23Na nuclear magnetic resonance spectroscopy (NMR) is increasingly being used to study Na+ gradients and fluxes in biological tissues. However, the quantitative aspects of 23Na NMR applied to living systems remain controversial. This paper compares sodium concentrations determined by 23Na NMR in intact rat hindlimb (n = 8) and excised rat gastrocnemius muscle (n = 4) with those obtained by flame photometric methods. In both types of samples, 90% of the sodium measured by flame photometry was found to be NMR-visible. This is much higher than previously reported values. The NMR measurements for intact hindlimb correlated linearly with the flame photometric measurements, implying that one pool of sodium, predominantly extracellular, is 100% visible. From measurements on excised muscle, in which extracellular space is more clearly defined, the NMR visibility of intracellular Na+ was calculated to be 70%, assuming an extracellular space of 12% of the total tissue water volume and an extracellular NMR visibility of 100%. 23Na transverse relaxation measurements were carried out using a Hahn spin echo on both intact hindlimb (n = 1) and excised muscle (n = 2) samples. These showed relaxation curves that could each be described adequately using two relaxation times. The rapidly relaxing component showed a T2 value of 3-4 ms and the slowly relaxing component a T2 of 21-37 ms. A spin lattice relaxation (T1) measurement on intact hindlimb yielded a value of 51 ms. These relatively long relaxation times show that the quadrupolar relaxation effect of Na+ complexing to large macromolecules or being otherwise motionally restricted is relatively weak. This is consistent with the high NMR visibilities reported here.

Animals↗
PubMed1978

Flexible valinomycin electrodes for on-line determination of intravascular and myocardial K+.

Flexible electrode systems capable of monitoring in vivo changes in venous and myocardial extracellular potassium activity were constructed using valinomycin-polyvinyl chloride matrix membrane and polyvinyl chloride tubing. Electrode impedance was 1--30 Momega, time constant 10--200 ms, drift less than 1 mV/h, and shelf life approximately 3 days (intramyocardial electrode) and approximately 6 wk (venous electrode). In vitro and in vivo accuracy were determined in 5 dogs and 18 pigs, anesthetized with sodium pentobarbital (35 mg/kg iv), with normal and elevated K+ levels. Serum and venous K+ concentration, determined using a K+ electrode with tip diameter of 1.5 mm, correlated well to serum K+ values determined by flame photometry (r = 0.997). Steady-state myocardial extracellular K+ concentration determined using double-barrel electrodes with total tip diameter of 0.6 mm also correlated well to the serum K+ concentration (r = 0.992). These electrode assemblies permit on-line, virtually instantaneous in vivo determination of intravascular and local myocardial extracellular K+ activity, a capability not previously available.

Animals↗
PubMed1985

Differences between CSF and plasma Na+ and K+ activities and concentrations.

[Na+] and [K+] determined by ion-selective electrodes (ISE) by direct potentiometric determination were compared with those obtained by flame photometry in plasma and in cisternal cerebrospinal fluid (CSF) obtained from pentobarbital-anesthetized dogs. Comparisons of pre- and postanesthesia values showed no change in plasma [Na+] but a 5% fall in plasma [K+]. CSF and plasma Na+ activities were identical, indicating that Na+ does not contribute to the potential difference between them. CSF K+ activity was 74% of that in plasma. The CSF-to-plasma molar and molal ratios differed from the activity (ISE) ratios. Concentrations of Na+ and K+ were also determined in an electrolyte solution and in the same solution with albumin added. Flame values differed from ISE values in plasma, CSF, and solutions. Albumin lowered flame values to a greater extent than ISE values. Bicarbonate lowered ISE values. ISE ratios, which equal activity ratios, rather than molar or molal ratios should be used in thermodynamic equilibrium equations, whereas molar concentrations should be used in electroneutrality equations or in determination of the strong ion difference.

Anesthesia↗