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PubMed2006

Biaxial microincision versus coaxial small-incision clear cornea cataract surgery.

OBJECTIVE: To compare clinical outcomes of biaxial microincision (1.5 mm) and coaxial small-incision (2.75 mm) clear cornea cataract surgery. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: Seventy eyes of 70 patients were examined at a German university eye hospital. INTERVENTION: The 70 patients (70 eyes) were assigned randomly (1:1) to a biaxial or conventional coaxial incision group. Both groups underwent phacoemulsification using pulsed ultrasound energy with variable duty cycles, followed by microincision intraocular lens implantation. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), astigmatism, laser flare photometry value, effective phacoemulsification time (EPT), and endothelial cell count were evaluated. RESULTS: The treatment groups did not differ in baseline characteristics (median BCVA of 20/40 preoperatively in both groups, P = 0.97). On postoperative day 1, BCVA was better in the biaxial group than in the coaxial group (20/25 vs. 20/33, P = 0.018). Eight weeks after surgery, median BCVAs were 20/20 in the biaxial group and 20/25 in the coaxial group (P = 0.015). Median changes in astigmatism were -0.15 diopters (D) in the biaxial group and -0.31 D in the coaxial group. Neither clinically relevant nor statistically significant differences were found in laser flare photometry values. Effective phacoemulsification time was >3 seconds in only 34% of biaxial procedures, versus 68% of coaxial procedures (P = 0.013). At 8 weeks after surgery, endothelial cell counts were decreased similarly in the biaxial (14.5%) and coaxial (14.1%) groups (P = 0.408). CONCLUSIONS: With the biaxial microincision technique, EPT is shorter and BCVA improves more rapidly, with no difference in astigmatism, laser flare photometry results, or endothelial cell count relative to the coaxial small-incision technique for phacoemulsification.

Adult↗
PubMed1979

Light scattering vs. microscopy for measuring average cell size and shape.

Light-scattering photometry is compared with electron and light microscopy as a source of information about the average size and shape of cells in population. Examined are the effects of limited instrument resolution, necessary experimental procedures, and cell heterogeneity. Information theory is used to survey the relative amounts of information provided by photometric and microscopic measurements. Then in model exploratory experiments, cell size and shape and changes therein are determined both by microscopy and by photometry for spherical and spheroidal cells. Scattering theory is used to calculate photometrically observed light from cell parameters. It is found that if certain other appropriate information about the morphological property of interest is available, then visible light photometry is the preferred method for obtaining quantitative information. It has good absolute sensitivity (0.01-0.10 micrometers resolution), its results are relatively unaffected by sample heterogeneity, it is nondestructive and compatible with many other techniques, it requires no sample preparation, and it provides its information in real time.

Animals↗
PubMed1998

Randomized study of the blood-aqueous barrier reaction after phacoemulsification and extracapsular cataract extraction.

PURPOSE: To compare the blood-aqueous barrier (BAB) breakdown after endocapsular phacoemulsification and extracapsular cataract extraction (ECCE). METHODS: Forty-two patients (64-82 years) enrolled for cataract surgery were randomly assigned to phacoemulsification (group I) or ECCE (group II). Patients with pseudoexfoliation syndrome, small pupils, glaucoma, uveitis, dark brown irides, diabetes, treatment with eye drops or anti-inflammatory drugs were excluded. In group I the patients were operated with continuous curvilinear capsulorhexis (CCC), phacoemulsification and implantation of a poly-(methyl methacrylate) (PMMA) intraocular lens (IOL) through a 5.2 mm self-sealing incision. In group II linear capsulotomy, nucleus expression and PMMA IOL implantation through a large incision (10-11 mm) were performed. The incision was sutured. Before surgery and three days and three months after surgery postoperative inflammation and BAB reaction were measured by laser flare photometry and anterior chamber fluorophotometry after intravenous administration of fluorescein. The BAB diffusion coefficient was calculated. Laser flare photometry was performed also after one and two years. RESULTS: According to fluorophotometry, ECCE induced significantly more postoperative BAB breakdown than did phacoemulsification at three days (p=0.00016) and three months (p=0.00829). Laser flare photometry showed more inflammation in the ECCE group than in the phacoemulsification group at three days postoperatively (p=0.00005). CONCLUSIONS: This study suggests that cataract surgery performed with a small, self-sealing incision, CCC and phacoemulsification induces a reduced surgical trauma with less BAB breakdown compared to ECCE using a large sutured incision, linear capsulotomy and nucleus expression.

Aged↗
PubMed2002

The theory and applications of pulse spectrophotometry.

Opening of the first door of pulse photometry gave us pulse oximeter. The next door opens to multiwavelength pulse photometry. It will give us a high performance pulse oximeter, providing a wide variety of clinical information simultaneously. This next generation of pulse photometry should further improve bedside monitoring and patient care.

Densitometry↗
PubMed1993

Evaluation of porfimer sodium fluorescence for measuring tissue transformation.

BACKGROUND: Neoplastic tissue can be detected by its increased fluorescence compared with surrounding normal tissue after the injection of the tumor-localizing compound porfimer sodium (Photofrin; Quadra Logic Technologies, Vancouver, BC, Canada). In vivo fluorescence photometry is a nonimaging photodetector technique that detects specific 690 nm fluorescence of the porphyrin by subtracting nonspecific 612 nm excitation from 630 nm excitation. The technique was applied in the developmental stages of the 9,10 dimethyl-1,2-benzanthracene (DMBA)-induced hamster buccal cheek pouch carcinoma model to (1) quantitate and characterize porfimer sodium fluorescence and uptake as it relates to lesion progression and biochemical changes and (2) determine whether porfimer sodium-induced fluorescence will vary with promotional and inhibitory stimuli. METHODS: Groups of Syrian Golden hamsters had their cheek pouch buccal mucosa exposed to a 0.5% DMBA in acetone three times per week for 6 weeks (premalignant lesions), 12 weeks (squamous cell carcinomas), or other specified durations. The rate of malignant transformation was either promoted (by either carbon dioxide laser incision or continued DMBA application) or inhibited (by the administration of either somatostatin analogue RC-160 [D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2] or bombesin antagonist RC-3095 [D-Tpi-Gln-Trp-Ala-Val-Gly-His-Leu psi (CH2NH)Leu-NH2]). Groups of DMBA-exposed hamsters were subsequently injected with 1.0 mg/kg of porfimer sodium during the various stages of tumor development. Twenty-four hours after injection, fluorescence levels were measured by in vivo fluorescence photometry. Samples of tumors, dysplastic mucosal tissue, and normal-appearing oral mucosa were biopsied and used for either tissue extraction assays, histopathologic examination, or tyrosine kinase activity assay as an index of rate of transformation. RESULTS: Results demonstrated that porfimer sodium is retained in DMBA-treated tissue. Fluorescence is completely accounted for by porfimer sodium uptake. The duration of exposure to carcinogen is proportional to porfimer sodium fluorescence. This relationship establishes that premalignant lesions can be distinguished from normal tissue by porfimer sodium uptake and fluorescence. The changes in increased tyrosine kinase activity paralleled the increase in porfimer sodium fluorescence. Alterations in the rate of tissue transformation produced equivalent alterations in porfimer sodium-induced fluorescence. CONCLUSIONS: These results suggest that porfimer sodium uptake and fluorescence can be used in a prognostic manner to diagnose and determine the course of transformation of individual lesions.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Fluorescent light photosensitivity in patients with systemic lupus erythematosus.

OBJECTIVE: To determine the prevalence of fluorescent light toxicity in patients with systemic lupus erythematosus (SLE). METHODS: SLE patients were polled about their symptomatic responses to sunlight and cool white fluorescent light. Photometry was used to determine the levels of ultraviolet (UV) emissions from fluorescent lamps. RESULTS: Thirteen of 30 photosensitive SLE patients described increases in disease activity following exposure to unshielded fluorescent lamps. Photometry indicated that these lamps emit substantial levels of UV-B (280-320 nm) radiation, which is toxic to patients with SLE. Standard acrylic diffusers absorbed this radiation, and their use was associated with almost no patient-reported problems. CONCLUSION: Fluorescent lamps, emitting UV-B radiation, induce disease activity in photosensitive SLE patients. Standard acrylic diffusers absorb UV-B radiation and appear to be protective against induction of disease activity with the use of fluorescent lamps.

Adult↗
PubMed1990

Variable NMR visibility of intracellular sodium induced by Na(+)-substrate cotransport in dog cortical tubules.

The intracellular sodium concentration [( Na+]i) of dog kidney cortical tubules was monitored by flame photometry and 23Na NMR using dysprosium tripolyphosphate as shift reagent. Upon addition of substrates cotransported with sodium, flame photometry showed an increase in [Na+]i while no change (glutamine, glucose) or even a decrease (lactate) in the Na+i NMR signal was observed. This discrepancy could not be explained by a lack of ATP prior to the addition of substrates or by a decrease of NMR visibility of Nai+ induced by binding of substrate to membrane transporters (and pump). We propose that a variation of the "apparent visibility" of Nai+ may occur, arising from either a compartmentation of Nai+ in dog cortical tubules or an inhomogeneous extracellular distribution of the shift reagent.

Adenosine Triphosphate↗
PubMed1984

The effect of anaerobiosis on adenosine triphosphate levels in larval Nippostrongylus brasiliensis and Haemonchus contortus.

The adenosine triphosphate (ATP) content of the pre-parasitic stages of Nippostrongylus brasiliensis, Haemonchus contortus (L1, L2 and L3) and the adults of the free-living nematode, Panagrellus redivivus, have been measured by bioluminescent photometry in aerated or near-anoxic conditions. The ATP content of the L1 and L2 stages of both parasitic species was unaltered by a lack of oxygen over a 90-min period. However, the L3 stage of both species and the adults of P. redivivus showed a significant fall in the level of ATP within 10 min of near-anoxia. This lower level of ATP was maintained during oxygen lack but the initial content was restored on return of the nematodes to aerobic conditions. The results suggest that measurement of ATP by bioluminescent photometry offers a readily measured and sensitive indicator of the capacity of a nematode to cope with transient changes in oxygen supply without undue metabolic stress.

Adenosine Triphosphate↗
PubMed1990

Immunohistochemical localization of corticotropin-releasing factor- and arginine vasotocin-like immunoreactivities in the brain and pituitary of the American bullfrog (Rana catesbeiana) during development and metamorphosis.

Immunoperoxidase staining for corticotropin-releasing factor (CRF) in the median eminence was sparce or absent from premetamorphic tadpoles, but increased dramatically by late prometamorphosis. Quantitative photometry revealed that CRF-like immunostaining material in the median eminence was most dense in metamorphic climax tadpoles. Arginine vasotocin (AVT)-like immunostaining material was visualized in perikarya of the magnocellular nucleus, with extensive fiber staining seen in the medial basal and infundibular hypothalamus as well as in the median eminence and pars nervosa of the pituitary. AVT-like immunoreactive perikarya were virtually absent in premetamorphic tadpoles, but their number increased greatly by Taylor-Kollros stage XII and continued to increase after this stage. Quantitative photometry revealed that AVT-like immunoreactivity in the pars nervosa increased greatly at Taylor-Kollros stage XII and remained intense after this stage. AVT-like immunoreactivity did not appear in the median eminence until Taylor-Kollros stage XVI. Localization of AVT-like immunoperoxidase staining around portal vessels in the median eminence suggests an anatomical mechanism for delivery of AVT to anterior pituitary corticotropes. These results indicate that both CRF and vasotocinergic neuronal systems develop just before the activation of interrenal steroidogenesis which occurs during the later stages of metamorphosis in this species.

Adrenocorticotropic Hormone↗
PubMed2004

Macular pigment density and aging, assessed in the normal elderly and those with cataracts and age-related macular degeneration.

PURPOSE: Increasing evidence has linked retinal lutein and zeaxanthin (termed macular pigment, MP) to the risk of age-related macular degeneration (AMD). Currently, however, studies differ regarding the question of whether MP declines with age or age has an effect in patient populations being assessed. This study assessed MP across the lifespan with an emphasis on assessing MP in a cross-section of elderly including those with lenticular or age-related macular degeneration, or both. DESIGN: Prospective, observational, cross-sectional study. METHODS SETTING: Institution. STUDY POPULATION: Cross-sectional study of normal, cataractous, and AMD subjects tested in Indianapolis, Indiana, including 390 subjects, 22 with cataracts and 59 with age-related macular degeneration. OBSERVATIONAL PROCEDURE: MP density was measured with a one-degree diameter test field at 460 nm using a psychophysical method based on heterochromatic flicker photometry. MAIN OUTCOME MEASURES: MP optical density. RESULTS: MP does not appear to change as a function of age (r = +.04) when examining subjects across the lifespan (from 18-88 years). There was a slight tendency (slope = -.0027, r = -.11) for MP to decline when only the elderly subjects were considered, but this trend was not significant (P < .12) for any of the groups considered (normal, cataractous, or AMD). CONCLUSIONS: MP does not change significantly with age, even when elderly subjects with cataracts and AMD are considered. Using heterochromic flicker photometry, elderly subjects display a full range of MP density that is similar to young subjects.

Adolescent↗
PubMed1985

Measurement of a wide range of intracellular sodium concentrations in erythrocytes by 23Na nuclear magnetic resonance.

The accuracy of the 23Na nuclear magnetic resonance (NMR) method for measuring the sodium concentration in erythrocytes was tested by comparing the NMR results to those obtained by emission-flame photometry. Comparisons were made on aqueous solutions, hemolysates, gels, ghosts, and intact erythrocytes. The intra- and extracellular 23Na NMR signals were distinguished by addition of the dysprosium tripolyphosphate [Dy(PPP)7-2] shift reagent to the extracellular fluid. The intra- and extracellular volumes of ghosts and cells were determined by the isotope dilution method. Our results indicate that greater than 20% of the intracellular signal remains undetected by NMR in ghosts and cells. When the cells are hemolyzed, the amount of NMR-detectable sodium varies depending on the importance of gel formation. In hemolysates prepared by water addition, the NMR and flame photometry results are identical. The loss of signal in ghosts, cells, and undiluted hemolysates is attributed to partial binding of the Na+ ion to intracellular components, this binding being operative only when these components exist in a gel state. In a second part, 31P NMR was used to monitor the penetration of the shift reagent into the cells during incubation. Our data demonstrate that free Dy3+ can slowly accumulate inside the red cell.

Animals↗
PubMed1993

A common lens nuclear area in Scheimpflug photographs.

Scheimpflug photography has been proven to be a useful method for documentation of opacification of the lens nucleus. In the present study, a common lens nuclear area (CNA) is established for photometry of nuclear cataract on Scheimpflug photographs. Using the established method, one measurement for one photograph, and one photograph for each subject is enough for the photometry of nuclear density. Further, this method allows detection of a 10% change in nuclear density between two occasions with a group of at least 7 subjects, and for independent groups with at least 95 subjects in each group (alpha = 0.05, beta = 0.10). It is anticipated that the CNA will provide a useful tool for quantitative determination of nuclear cataract.

Aged↗
PubMed2000

Erythropoietin-induced rheological changes of rat erythrocytes.

The effects of recombinant human erythropoietin (rhEPO) on red blood cell (RBC) rheological properties were investigated in rats. Rats received intramuscular injections of 150 U/kg/d rhEPO for 5 d, following which blood samples were obtained 1, 5 or 10 d later. RBC deformability was assessed by determining cell transit times through 5-microm micropores (CTA) and RBC shape recovery time constants via photometry, aggregation in plasma and dextran was measured by photometry and RBC electrophoretic mobility was determined in a cylindrical electrophoresis system. RBC aggregation was found to be significantly decreased on day 5 after rhEPO treatment (P < 0.05), yet was unchanged from control on days 1 and 10. Mean RBC micropore transit times remained unchanged, but the distributions of transit times were altered; compared with control, the 5th percentiles on both days 1 and 5 were decreased and the 95th percentile on day 1 was elevated. Electrophoretic mobility of RBCs in phosphate-buffered saline was significantly increased on day 5 after rhEPO treatment (P < 0.05), with mobility measurements in dextran 500 (MW = 500 kDa) solutions suggesting that the cells' surface properties related to the formation of a 'depletion layer' may be altered on day 1. These results indicate that the rheological behaviour of RBC as a consequence of rhEPO treatment are temporal and are affected by the presence of reticulocytes as well as by the average age of the circulating cells.

Animals↗
PubMed1995

A comparison of four bedside methods of hemoglobin assessment during cardiac surgery.

The purpose of this study was to compare the accuracy of conductivity, adjusted conductivity, photometric, and centrifugation methods of measuring or estimating hemoglobin (Hb) with Coulter measured HB as the reference. These bedside methods were studied in 25 cardiac surgery patients during euvolemia and hemodilution and after salvaged autologous red blood cell transfusion. In vivo patient blood samples were obtained before induction, at the start of cardiopulmonary bypass (CPB), after CPB, and after blood transfusion. In 10 patients, blood was sampled in vitro from units of processed blood. Hb values were determined using conductivity by Stat-Crit, adjusted conductivity by Nova Stat Profile 9, bedside photometry by HemoCue, and centrifugation methods. The calculated bias values of Coulter test method Hb (mean +/- SD) for in vivo patient blood samples (n = 90) were: Stat-Crit = 0.6 +/- 0.8 g/dL; Nova Stat Profile 9 = -0.7 +/- 0.4 g/dL; HemoCue = -0.1 +/- 0.2 g/dL; and centrifuge = 0.1 +/- 0.5 g/dL (P < 0.0001). Hb bias values (g/dL) for in vitro samples (n = 10) obtained from processed blood were Stat-Crit = 5.1 +/- 0.6; Nova Stat Profile 9 = 3.0 +2- 0.6; HemoCue = 0.4 +/- 0.4; and centrifuge = 0.6 +/- 0.3 (P < 0.0001). Hb assessment by different test methods may be significantly affected during hemodilution and after blood transfusion. In vitro conditions exaggerated the inaccuracy of conductivity and adjusted conductivity Hb estimates. The rank order of closest approximation to the Coulter measurement for all in vivo blood samples was provided by bedside photometry, followed by centrifugation, adjusted conductivity, and uncorrected conductivity methods.

Analysis of Variance↗
PubMed1979

Luminous efficiency in the red-green region of the spectrum.

Monochromatic-test stimuli were produced with a double monochromator with a neutral wedge linked to the mechanism for changing wavelength. Only minor adjustments of the width of the entrance slit were required to produce monochromatic stimuli of equal luminance. For any given wavelength, the radiance of the stimulus was proportional to the width of the entrance slit. These test stimuli were adjusted to equal luminance, using various criteria: (1) flicker, (2) direct comparison, (3) distimulus matching, and (4) step-by-step. For two out of three subjects, measurements made by the distimulus method agree with flicker measurements when the primaries are adjusted to be equal by flicker photometry. They provide a test for additivity. Red and green, which are equal in luminance to yellow by flicker photometry, are brighter than yellow by direct comparison and also by the step-by-step method of assessment. The step-by-step data prove that the discrepancy between flicker and direct comparison involves more than confusion between saturation and brightness and is consistent with the notion of summation of responses in the chromatic and achromatic channels, as proposed by Ives and others.

Color Perception↗
PubMed1991

Serum C-reactive protein in childhood meningitis in countries with limited laboratory resources: a Chilean experience.

Quantitative C-reactive protein (CRP) was determined sequentially by nephelometry and photometry from a finger prick serum sample in 67 children with bacterial meningitis (BM) and 16 children with aseptic meningitis (AM). The initial mean CRP value of 180 mg/liter in children with BM differed significantly from the 12 mg/liter found in those with AM (P less than 0.001). In BM a slow descent instead of rapid normalization or a secondary increase in sequential CRP values were early indicators of complications during recovery, such as resistance to the antibiotic. A significant difference in the mean CRP values between uneventful and complicated courses of BM was observed from the fourth day on (P less than 0.001). The measurements obtained with nephelometry correlated reliably with the more widely available photometry (r = 0.99). Easily performed rapid CRP determinations can considerably improve the quality of care in meningitis patients, especially in those situations where facilities for performing bacterial cultures or antibiotic susceptibility testing are not available.

C-Reactive Protein↗
PubMed1996

On-line laser-photometric monitoring of aerosol deposition in ventilated rabbit lungs.

A photometric technique was developed for on-line measurement of aerosol deposition in isolated, ventilated, and perfused rabbit lungs. A jet nebulizer was used for aerosolization of saline (hygroscopic particles) and di(2-ethylhexyl) sebacate (nonhygroscopic particles). Aerosol concentration (laser photometer, constructed for measurements in rabbit lungs) and flow rate (commercial pneumotachograph) were continuously monitored at the inlet of the tracheal cannula. Computer-assisted data processing allowed the breath-by-breath calculation of inhaled and exhaled aerosol mass, thus providing the deposition fraction. With the use of hygroscopic particles, however, this approach was hampered by the humidity-induced particle growth in the airways, leading to an overestimation of the aerosol concentration in exhaled air. This effect was corrected by an algorithm using a "particle growth factor" derived breath by breath from the photometer signal. To test the reliability of this approach, saline particles carrying technetium-99m label were aerosolized into rabbit lungs with the use of various ventilator settings, and the aerosol deposition was assessed in parallel by photometry and by radioactivity detection over the lung and over a trap in the exhaled-air circuit. Superimposable curves of cumulative aerosol deposition, with changes in kinetics dependent on the ventilator mode, were obtained. For a given ventilator setting, absolute values of the deposition fraction were 0.32 +/- 0.04 (radiotracer quantification) and 0.36 +/- 0.04 (photometry; means +/- SD; n = 4). We conclude that the presented laser-photometric technique allows reliable on-line monitoring of the deposition of both nonhygroscopic and hygroscopic aerosol particles in ventilated lungs.

Aerosols↗
PubMed1999

Blood-aqueous barrier disruption in experimental anterior segment ischemia in rabbit eyes.

The blood-aqueous barrier (BAB) in experimentally induced anterior segment ischemia (ASI) following strabismus or retinal detachment surgery in pigmented rabbits was evaluated by laser flare photometry. Four simultaneous rectus tenotomies produced a significantly higher flare value on the 1st postoperative day. Obstruction of one or two vortex veins produced significantly high flare values on the 1st and 3rd postoperative days. Scleral buckling with interference of one vortex vein produced a higher flare value than that with buckling alone. Interference of three vortex veins by diathermy and the encircling procedure produced serious ASI. Disruption of BAB in ASI can be detected quantitatively with laser flare photometry. Introduction of prostaglandin synthetase inhibitor resulted in a significant reduction of flare values following surgery. Prostaglandin synthetase inhibitor can partly ameliorate BAB disruption.

Animals↗