SEARCH · Search PubMed

Results for “Photometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,405 records · Page 78Linked to original sources

PubMed1982

Cytofluorometric determination of nuclear DNA in living and preserved algae.

Three DNA-localizing fluorochromes used in conjunction with epi (incident) UV illumination were examined for sensitivity and selectivity for the cytofluorometric determination of nuclear DNA in ten species of six algal genera: Mougeotia, Oedogonium, Sirogonium, Spirogyra and Zygnema among the green algae, and the marine red alga Polysiphonia boldii. In comparison with absorption photometry for the determination of nuclear DNA, the cytofluorometric procedure proved to be simpler and considerably more sensitive. Following staining with 4',6-diamidino-2-phenylindole (DAPI), nuclei fluoresce blue-white, the fluorescence intensity of the DNA-DAPI complex being considerably greater than that of the unbound dye molecule. Algal strains stained with 2,5-bis[4'-aminophenyl(1')]-1,3,4-oxadiazole (BAO) also showed brilliant blue-white nuclear fluorescence. Although the BAO schedule requires the use of freshly prepared dye and sulfite water, and careful control of hydrolysis, nuclear fluorescence of the stained specimens does not fade under irradiation of the UV beam as rapidly as it does with certain other fluorochrome procedures. A more useful fluorochrome was the fungal antibiotic mithramycin. Its staining schedule is simple and the bright orange-yellow fluorescence of the nuclei is associated with an exceptional degree of sensitivity and specificity for DNA. Forty-eight-year-old preserved filaments of Spirogyra jatobae, stained with either BAO or mithramycin, exhibited a fluorescence brilliance of nuclear and chloroplast DNA equal to that of fresh specimens of this species. The three schedules, but particularly the one with mithramycin, have proven useful in providing indirect evidence for variation in ploidy level in several of the above algal genera, and in verifying the assumed ploidy level of the gametophyte (haploid) and tetrasporophyte (diploid) of Polysiphonia boldii.

Cell Nucleus↗

PubMed1991

Starch removal from potato tuber sections.

Heating plant sections at 90 C with 0.5% aqueous ammonium oxalate is required to remove pectins. When applied to tissues rich in starch such as potato, this step produces heavy dextrinization of the starch which hinders subsequent evaluation of the extinction values of the cell walls. To overcome this a method has been devised to brush away the starch granules from the sections with a thin paint brush, just after paraffin removal by xylene. The slide is then processed as usual: pectins are removed by heat treatment, cell walls are stained with PAS and the stain intensity can be evaluated by photometry.

Cell Wall↗

PubMed1997

Enhanced protection against peroxidation-induced mortality of aortic endothelial cells by ascorbic acid-2-O-phosphate abundantly accumulated in the cell as the dephosphorylated form.

Bovine aortic endothelial BAE-2 cells exposed to the peroxidizing agent, tert-butylhydroperoxide (t-BuOOH) or 2,4-nonadienal (NDE), suffered from disruption of cell membrane integrity and from reduction of mitochondrial dehydrogenase activity as assessed by fluorometry using ethidium homodimer and photometry using WST-1, respectively. The cells were protected from t-BuOOH-induced injury more markedly by L-ascorbic acid-2-O-phosphate (Asc2P) stably masked at the 2,3-enediol moiety, which is responsible for the antioxidant ability of L-ascorbic acid (Asc), than by Asc itself. In contrast, NDE-induced membrane disruption but not mitochondrial dysfunction was prevented by Asc2P, whereas Asc exhibited no prevention against both types of injury. The amount of intracellular Asc was 7.2- to 9.0-fold larger in Asc2P-administered BAE-2 cells, where the intact from Asc2P was not detected, than in Asc-administered cells as assessed by HPLC of cell extract with detection by coulometric ECD and UV. During transmembrane influx into the cell, Asc2P was concentrated as highly as 70- to 90-fold relative to the extracellular Asc2P concentration, whereas Asc was 8- to 13-fold concentrated as estimated based on an intracellular water content of 0.59 pL/cell determined by [14C]PEG/gas chromatography. Thus, Asc2P but not Asc is highly concentrated in the aqueous phase of the cell after prompt dephosphorylation, and may thereby render the cell more resistant to t-BuOOH-peroxidation assumedly via scavenging of intracellular reactive oxygen species than to peroxidation with the less hydrophilic agent NDE.

Animals↗

PubMed1988

In vitro study of lithium carbonate adsorption by activated charcoal.

The purpose of this study was to determine whether lithium carbonate (Li2CO3) is effectively adsorbed by activated charcoal (AC). Either 0 (control), 1.5, 3.0 or 9.0 grams of AC were added to Li2CO3 (300 mg) in distilled deionized water or simulated gastric fluid USP, filtered and and the filtrate analyzed for lithium by flame photometry. Adsorption of lithium was dependent on AC concentration and pH. In water, lithium was 14.7%, 26.5% and 40.4% adsorbed at AC:Li2CO3 ratios of 5:1, 10:1 and 30:1, respectively (p less than 0.05). In simulated gastric fluid, there was no significant adsorption at any of the AC concentrations studied. Since simulated gastric fluid more closely resembles in vivo conditions, the efficacy of AC in lithium carbonate overdoses is questionable but in vivo studies are needed to confirm these findings.

Adsorption↗

PubMed2000

High extracellular potassium and its correlates after severe head injury: relationship to high intracranial pressure.

Disturbed ionic and neurotransmitter homeostasis are now recognized to be probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brian injury (TBI). Evidence obtained from animal models indicates that posttraumatic neuronal excitation via excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with intracranial pressure (ICP), outcome, and also with the levels of dialysate glutamate, lactate, and cerebral blood flow (CBF) so as to determine the role of ischemia in this posttraumatic ionic dysfunction. Eighty-five patients with severe TBI (Glasgow Coma Scale score < 8) were treated according to an intensive ICP management-focused protocol. All patients underwent intracerebral microdialyis. Dialysate potassium levels were analyzed by flame photometry, as were dialysate glutamate and dialysate lactate levels, which were measured using high-performance liquid chromatography and an enzyme-linked amperometric method in 72 and 84 patients respectively. Cerebral blood flow studies (stable Xenon--computerized tomography scanning) were performed in 59 patients. In approximately 20% of the patients, potassium values were increased (dialysate potassium > 1.8 mmol). Mean dialysate potassium (> 2 mmol) was associated with ICP above 30 mm Hg and fatal outcome. Dialysate potassium correlated positively with dialysate glutamate (p < 0.0001) and lactate levels (p < 0.0001). Dialysate potassium was significantly inversely correlated with reduced CBF (p = 0.019). Dialysate potassium was increased after TBI in 20% of measurements. High levels of dialysate potassium were associated with increased ICP and poor outcome. The simultaneous increase of potassium, together with dialysate glutamate and lactate, supports the hypothesis that glutamate induces ionic flux and consequently increases ICP due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered potassium reactivity in cerebral blood vessels after trauma.

Adolescent↗

PubMed2000

High level of extracellular potassium and its correlates after severe head injury: relationship to high intracranial pressure.

OBJECT: Disturbed ionic and neurotransmitter homeostasis are now recognized as probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brain injury (TBI). Evidence obtained in animal models indicates that posttraumatic neuronal excitation by excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with measurements of intracranial pressure (ICP), patient outcome, and levels of dialysate glutamate and lactate, and cerebral blood flow (CBF) to determine the role of ischemia in this posttraumatic ion dysfunction. METHODS: Eighty-five patients with severe TBI (Glasgow Coma Scale Score < 8) were treated according to an intensive ICP management-focused protocol. All patients underwent intracerebral microdialyis. Dialysate potassium levels were analyzed using flame photometry, and dialysate glutamate and dialysate lactate levels were measured using high-performance liquid chromatography and an enzyme-linked amperometric method in 72 and 84 patients, respectively. Cerebral blood flow studies (stable xenon computerized tomography scanning) were performed in 59 patients. In approximately 20% of the patients, dialysate potassium values were increased (dialysate potassium > 1.8 mM) for 3 hours or more. A mean amount of dialysate potassium greater than 2 mM throughout the entire monitoring period was associated with ICP above 30 mm Hg and fatal outcome, as were progressively rising levels of dialysate potassium. The presence of dialysate potassium correlated positively with dialysate glutamate (p < 0.0001) and lactate (p < 0.0001) levels. Dialysate potassium was significantly inversely correlated with reduced CBF (p = 0.019). CONCLUSIONS: Dialysate potassium was increased after TBI in 20% of measurements. High levels of dialysate potassium were associated with increased ICP and poor outcome. The simultaneous increase in dialysate potassium, together with dialysate glutamate and lactate, supports the concept that glutamate induces ionic flux and consequently increases ICP, which the authors speculate may be due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered vasoreactivity in cerebral blood vessels caused by higher levels of potassium after trauma. Additional studies in which potassium-sensitive microelectrodes are used are needed to validate these ionic events more clearly.

Adolescent↗

PubMed2005

Mechanism of diarrhea in microscopic colitis.

AIM: To search the pathophysiological mechanism of diarrhea based on daily stool weights, fecal electrolytes, osmotic gap and pH. METHODS: Seventy-six patients were included: 51 with microscopic colitis (MC) (40 with lymphocytic colitis (LC); 11 with collagenous colitis (CC)); 7 with MC without diarrhea and 18 as a control group (CG). They collected stool for 3 d. Sodium and potassium concentration were determined by flame photometry and chloride concentration by titration method of Schales. Fecal osmotic gap was calculated from the difference of osmolarity of fecal fluid and double sum of sodium and potassium concentration. RESULTS: Fecal fluid sodium concentration was significantly increased in LC 58.11+/-5.38 mmol/L (P<0.01) and CC 54.14+/-8.42 mmol/L (P<0.05) than in CG 34.28+/-2.98 mmol/L. Potassium concentration in LC 74.65+/-5.29 mmol/L (P<0.01) and CC 75.53+/-8.78 mmol/L (P<0.05) was significantly less compared to CG 92.67+/-2.99 mmol/L. Chloride concentration in CC 36.07+/-7.29 mmol/L was significantly higher than in CG 24.11+/-2.05 mmol/L (P<0.05). Forty-four (86.7%) patients had a secretory diarrhea compared to fecal osmotic gap. Seven (13.3%) patients had osmotic diarrhea. CONCLUSION: Diarrhea in MC mostly belongs to the secretory type. The major pathophysiological mechanism in LC could be explained by a decrease of active sodium absorption. In CC, decreased Cl/HCO3 exchange rate and increased chloride secretion are coexistent pathways.

Case-Control Studies↗

PubMed2006

Monocytes in systematic inflammatory response syndrome: differences between sepsis and acute pancreatitis.

AIM: To unravel the differences between systematic inflammatory response syndrome (SIRS) of acute pancreatitis compared to the same syndrome in sepsis. METHODS: Twenty-five patients were enrolled, 12 with sepsis and 13 acute pancreatitis. After diagnosis 20 mL blood was sampled. Half were assayed for isolation of monocytes and 10 mL was centrifuged for serum test of tumor necrosis factor alpha (TNFalpha and interleukin-6 (IL-6). Half of monocytes were incubated in the presence of patients' serum and supernatants were collected. The other half was treated for estimation of optical photometry under caspase-3 inhibition. TNFalpha and IL-6 were estimated by an enzyme immunoassay. RESULTS: median+/-SE of serum IL-6 in septic patients and acute pancreatitis patients was 192.30+/-35.40 ng/L and 21.00+/-16.05 ng/L, respectively (P<0.01). Respective values of caspase-3 were 0.94+/-0.17 pmol/min 10(4) cells and 0.34+/-0.09 pmol/min 10(4) cells (P<0.05). IL-6 of monocyte supernatants of patients with sepsis was significantly increased after addition of patients' serum, while that of patients with acute pancreatitis did not show significant difference. CONCLUSION: The data have shown that monocyte activity is different between acute pancreatitis and sepsis. This phenomenon might be explained as a different pathway to the pro-inflammatory cytokines release or could be a novel anti-inflammatory response in acute pancreatitis.

Acute Disease↗

PubMed2004

Comparative study of serum Na(+ )and K(+ ) levels in senile cataract patients and normal individuals.

Many factors such as aging, changes in blood electrolytes levels, and possibly family history are involved in senile cataract formation. Changes in serum electrolytes levels can induce changes in aqueous electrolytes levels and effect on lens metabolism and probably cataract formation. In this paper, we study serum level of Na(+ )and K(+) in senile cataract patients and normal individuals. Methods and materials: 155 senile cataract patients scheduled for cataract surgery in eye clinic of Rasoul hospital and 155 normal individuals were selected. Serum Na(+) and K(+) levels were measured by Flame Photometry technique and means compared between two groups by t-test. Results: 1. Mean serum Na(+) level in senile cataract patients and normal individuals was 144.96 +/- 6.04 mEq/lit and 140.88 +/- 2.27 mEq/lit respectively, and there was statistically significant difference (P<0.0001). 2. Mean serum K(+) level in senile cataract patients and normal individuals was 4.20 +/- 0.34 mEq/lit and 4.15 +/- 0.32 mEq/lit respectively, and there was no statistically significant difference. Conclusion: Serum Na(+ )level in senile cataract patients was higher than normal individuals in this study. This result might suggest that diets with high Na(+) content are a risk factor for age-related cataract formation, as high Na(+) content of the diet leads to high level of serum Na(+), which in turn contributes to formation of age-related cataract.

Journal Article↗

PubMed1986

Serum chemistry and evidence of renal failure in the North Atlantic fin whale population.

Serum electrolytes, urea nitrogen, creatinine, albumin and globulin were studied in fin whales (Balaenoptera physalus) caught by commercial whalers in the North Atlantic (Denmark Strait area). Blood samples were obtained by catchment or cardiac puncture within 5-15 min of death and analyzed using automated spectrophotometric methods and flame photometry. Osmolality was determined for two serum samples by a vapor pressure method. Linear regressions determined for each measured serum variable vs. chase time suggested that pursuit of the whales prior to capture had no substantive effect on measured serum chemistry. As in other cetaceans, serum sodium, chloride, urea nitrogen and osmolality were distinctly higher in the fin whale than in terrestrial mammals. The total concentration of serum proteins, however, was 1.4-1.8 g/dl lower, on average, than reported in small toothed whales, and was similar to that of domesticated animals. One animal in this population showed alterations in serum chemistry which were consistent with renal failure.

Animals↗

PubMed2006

Intraerythrocyte and serum electrolytes in diabetic patients with hypertension.

OBJECTIVE: To determine the serum and intraerythrocyte concentrations of vasoactive ions in patients of diabetes mellitus of either gender with hypertension. DESIGN: Cross-sectional study. PLACE AND DURATION OF STUDY: The Department of Biochemistry, University of Karachi, from May-June 2002. PATIENTS AND METHODS: The study was conducted on 48 volunteers. Out of 48, 24(12 men and 12 women) were hypertensive patients with diabetes mellitus. Remaining (12 men and 12 women) were normal healthy subjects. Biochemical estimations were done by flame photometry and spectrophotometry. Data were analyzed by Two-way ANOVA followed by Newman-Keuls test. RESULTS: A decrease in serum concentrations of sodium, calcium, magnesium, phosphorus, chloride and intraerythrocyte potassium and an increase in the levels of glucose, haematocrit and intraerythrocyte sodium was observed in both male and female patients with diabetes mellitus and hypertension. No significant changes were observed in serum potassium levels. CONCLUSION: The results suggest that dysregulations of electrolyte balance caused by hyperinsulinemia or altered glucose metabolism may lead to hypertension.

Cross-Sectional Studies↗

PubMed1996

Recommendation on mean molar activity coefficients and single ion activity coefficients of solutions for calibration of ion-selective electrodes for sodium, potassium, and calcium determination. IFCC Scientific Division Working Group on Selective Electrodes.

In principle, flame photometry measures substance concentration, and ion-selective electrodes (ISEs) measure ion activity. However, the situation regarding the comparison of results from the two techniques when applied to blood plasma is complex. The problem can be approached experimentally from the point of view of calibration of ISEs with concentration calibrators, and similar procedures are adopted for commercial ISE-based clinical analyzers. Nevertheless, there is interest in the evaluation of single ion activities in blood plasma and solutions simulating its ionic composition. Solutions are proposed for calibrating ISEs for the determination of sodium, potassium, and calcium. It is recommended that the values for single ion activities derived from the Pitzer treatment of mixed electrolyte solutions be adopted, because, although this has some empirical features, it has a sounder theoretical basis than the previously used Stokes-Robinson-Bates hydration approach.

Calcium↗

PubMed1999

[Components of Serratula species; screening for ecdysteroid and inorganic constituents of some Serratula plants].

Ecdysteroid and inorganic components were analyzed from several plant species belonging to Caryophyllaceae family, such as in the cases of Serratula tinctoria, Serratula wolffii, Serratula coronata (20-hydroxyecdysone and inorganic components) and Jurinea mollis, Serratula gmellinii and Leuzea carthamoides (inorganic components, only). The 20-hydroxyecdysone content was determined using thin-layer chromatography after a simple clean up that had been performed by solid-phase extraction. Inorganic constitutents were determined using either ICP or flame photometry. Vegetation dependence of both 20-hydroxyecdysone and inorganic elements was studied. Serratula coronata shows remarkable high 20-hydroxyecdysone (2.3%, in April) and the studied Serratula plants gave a minimum of 20-hydroxyecdysone in June. Favorable period for harvesting is suggested as July and August, through the blossoming of these plants. Potassium and 20-hydroxyecdysone content gave a similar tendency considering their vegetation dependence, while the magnesium content moved toward opposite direction. The calcium contents of Serratula tinctoria, Serratula wolffii and Serratula coronata were found between 2.2% and 3.8%, which values are high relative to the other medicinal plants. At the same time, the Cu content of the ecdysteroid producing (and screened) Caryophyllaceae plants is low. The Fe, Mn and Mg contents of Serratula coronata are high, even higher than that of the Leuzea carthamoides. Our results have suggested the importance of analysis and control of inorganic constituents of crude plant extracts used for medicinal and recreational purposes.

Ecdysteroids↗

PubMed1999

[Follow-up study of iodine status in neonates and their mothers in 2 regions of the Czech Republic after a 3-year intervention].

BACKGROUND: The worldwide elimination of iodine deficiency is at present one of the priorities of WHO. The highest risk group with regard to sequelae of inadequate iodine supplies are even in case of a milder iodine deficiency, human foetuses during the foetal and early infantile period (endemic cognitive disorder). An epidemiological survey in three areas of the Czech Republic (Prague, Príbram, Ustí n. Labem) in 1993-95 in 5-day old infants and their mothers provided evidence of a medium grade iodine deficiency in Prague and the Príbram area. The objective of the epidemiological check-up survey of ioduria of neonates in 1997 (Prague, Príbram) is the evaluation of the success of preventive provisions which were implemented for a period and educational activities, recommendations to take 100 micrograms iodine to all pregnant and lactating mothers, fortification of infant foods with iodine, increasing and improving the standard of iodine in table salt (27 +/- 7 mg 1/kg salt as potassium iodate). METHODS AND RESULTS: In 1997 the ioduria of two groups of full-term neonates and their mothers was assessed on the fifth day after delivery. Fifty neonates and their mothers were from Prague, 50 from Príbram. Ioduria was assessed in morning urine samples by the method of Ing. Bílek (National list of laboratory items MZ, SLP type N-SPA-BANO, code Joduria (photometry), key BIAAA, published in 1997). The results were statistically computed using Bartlett's chi-aquare and Kruskalov-Vallis' H test and Student's t-test. The median of ioduria in Prague neonates was 7.93 micrograms 1/100 ml and in Príbram neonates 7.83 micrograms 1/100 ml urine. The median values of maternal ioduria were 5.90 micrograms 1/100 ml in Prague and 7.23 micrograms 1/100 ml urine in Príbram. CONCLUSIONS: The median ioduria values of neonates from two areas (Prague and Príbram), previously (93-94) in the zone of medium iodine deficiency, increased significantly during three years of intervention and in 1997 they reached normal levels of ioduria for the given age group.

Czech Republic↗

PubMed1999

A practical method for measuring macular pigment optical density.

PURPOSE: Increasing evidence indicates that the macular pigments (MP) protect the central retina and may retard macular disease. For that reason, a practical method for measuring MP that does not require elaborate optics and can be applied to diverse populations by operators with a modest amount of experience was developed and validated. METHODS: A small tabletop device based on light-emitting diodes (LEDs) as the light source with electronic controls was constructed. Macular pigment was measured with the tabletop device with a 1 degrees test stimulus at 460 nm using heterochromatic flicker photometry, and the results were compared with measurements using a traditional three-channel Maxwellian view system with a xenon-arc source. RESULTS: Macular pigment density of 30 subjects (age range, 16-60 years) was measured with both stimulus systems. Macular pigment measured with the LED tabletop device in free view was highly correlated with MP measured in Maxwellian view (y = -0.03 + 1.06x, r = +0.95). The average absolute difference between the two techniques was 0.04 (SD, 0.03). The new technique was not significantly affected by variations in lens optical density, pupil size, or small head movements. CONCLUSIONS: Psychophysical measurement of MP provides a unique opportunity to make repeated noninvasive assessment of the concentration of a protective nutrient in the retina. The availability of this new device should make this measurement technology accessible to a wide variety of investigators for application to diverse populations.

Adolescent↗

PubMed1999

Distribution and function of angiotensin II receptors in mouse spermatozoa.

Previous work indicates that angiotensin II (AngII) stimulates sperm motility and acrosomal exocytosis. Here we determined the distribution of AngII receptors on mouse sperm by immunocytochemistry and used Ca2+ probe photometry to examine their coupling to sperm regulatory pathways. We found both AT1 and AT2 receptors localized on the acrosomal region of the sperm head. The AT1 receptor, but not the AT2 receptor, is found also on the principal piece of the sperm tail. Local perfusion of motile but nonprogressive sperm with 0.1-1 microM of AngII evokes a rapid, substantial rise in intracellular [Ca2+]. This response is blocked by losartan, a specific antagonist of the AT1 receptor. These results indicate that sperm possess functional AT1 receptors that are distributed to sites that may allow selective control of motility and exocytosis. They also suggest that the AT2 receptors detected by immunoreactivity are either nonfunctional or are not coupled to Ca(2+)-mediated signalling mechanisms.

Angiotensin II↗

PubMed1975

[Reproducible and congruent radiographs for the study of bone structure].

Radiograms that are reproducible and are as identical as possible are an absolute prerequisite for objective early diagnosis of the smallest changes in the bone structure. Changes that are no longer visible to the naked eye, are recorded by photometry and can be represented objectively by computerized evaluation. It is the object of this study to develop a method for taking roentgenograms with films generally used in the dental office, which allows to always the area always to be radiographed reproducibly. The x-ray machine is described and tested on four patients. The radiograms are photometrically scanned and entered into a computer in order to check the location of the radiograph. The results show that with our method it is possible to take identical radiograms at different times.

Bone Development↗

PubMed2000

Competency-based optics instruction.

BACKGROUND: The Competency-Based Instruction (CBI) system has been used to teach physics for more than 20 years in the Michigan State University Physics Department. In this approach, traditional lectures have been replaced by a learning environment that contains a variety of instructional aids, including written materials, computer-assisted instruction, and interactions with a consultant. The CBI system allows students to adjust their pace through the course, moving nearly as quickly as they are able, with constant feedback to the student on his or her progress. METHODS: I have used an adapted version of the CBI system for use in the Physical Optics and Photometry course of the University of Missouri-St. Louis, School of Optometry for four years. This article will describe the mechanics of the system and discuss experiences with it.

Computer-Assisted Instruction↗