scholarly journals STUDIES IN HISTOCHEMISTRY: LXXXII. DETERMINATION OF VITAMIN A IN MICROGRAM SAMPLES OF TISSUE AND ITS QUANTITATIVE HISTOLOGICAL DISTRIBUTION IN THE RAT ADRENAL

1965 ◽  
Vol 13 (8) ◽  
pp. 640-646 ◽  
Author(s):  
PAUL K. NAKANE ◽  
DAVID GLICK
Keyword(s):  
Standard Deviation ◽  
Vitamin A ◽  
Analytical Data ◽  
Dry Weight ◽  
Optimal Conditions ◽  
Protein Nitrogen ◽  
Tissue Samples ◽  
The Mean ◽  
Mean Concentration

A fluorometric procedure is presented for the determinations of vitamin A in small tissue samples, e. g., microtome sections, to enable correlation of analytical data with histology. Measurements may be made over the range, 3 x 10–12–6 x 10–10 moles of the vitamin (0.86-17 mµg of vitamin A alcohol), the quantities per 60 µl of solution used in the microcuvettes for fluorometry. Optimal conditions for certain of the analytical steps and for extraction of the vitamin from tissue were studied. Quantitative recoveries of vitamin added to tissue were obtained, and the reproducibility of the analysis of tissue was observed to have a standard deviation of 4%. In preliminary experiments, a mean vitamin A per rat adrenal was found to be 2.3 mµmoles, and the mean concentration 317 mµmoles/g, dry weight. A study of the quantitative histological distribution of the vitamin in the adrenal revealed greatest concentrations (4.7 x 10–12 moles/µg of proten-nitrogen) in the region where the glomerulosa and fasciculata join, and the concentration fell steadily through the fasciculata and reticularis to a low (0.9 x 10–12 moles/µg of protein-nitrogen) in the medulla.

scholarly journals DETERMINATION OF TRITIUM IN MICROGRAM TISSUE SAMPLES: DISTRIBUTION OF EXOGENOUS 3H-CHOLESTEROL IN THE RAT ADRENAL CORTEX

1971 ◽  
Vol 19 (1) ◽  
pp. 46-50 ◽  
Author(s):  
MARTTI PARVINEN ◽  
MIKKO NIEMI
Keyword(s):  
Dry Weight ◽  
Cortical Layers ◽  
Ether Anesthesia ◽  
Tissue Samples ◽  
Unilateral Adrenalectomy ◽  
Tritium Activity ◽  
Metal Cathode ◽  
Thick Steel ◽  
The Mean

An internal sample metal cathode proportional counter for measurements of low tritium activity in biologic samples of microgram size has been designed. Using a guard detector operating in anticoincidence together with a thick steel castle, a background of 0.5 cpm and an efficiency of 54.6% for tritium were realized. Radioactivities down to 2 pC (4.4 dpm) can be measured with an accuracy of ±16%. Tritium activity was measured in single adrenal cortical sections of 7 µm in thickness and 0.4 mm in diameter having a mean dry weight of 1.2 µg. The cortical layers were identified histologically from alternate sections. Two days after the injection of tritiated cholesterol the highest radioactivity was encountered in the outer fascicular zone (39 dpm/µg). The distribution of the radioactivity within the cortex was equal in all animals, although the mean level varied individually. The glomerulosa and reticularis contained usually about one-third of the activity in the outer fasciculata. Ether anesthesia and unilateral adrenalectomy caused significant decrease in the incorporation of the cholesterol, which was not further reduced by an injection of adrenocorticotropin. Ninety-five per cent of the radioactivity in the adrenals was bound to cholesterol or its esters 2 days after the injection.

Collaborative Study of a Fluorometric and Thin Layer Chromatographic Determination of Aminacrine and Its Salts in Drug Preparations

1967 ◽  
Vol 50 (3) ◽  
pp. 680-682
Author(s):  
Laura A Roberts
Keyword(s):  
Standard Deviation ◽  
Thin Layer ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Assay Method ◽  
The Mean ◽  
Layer Chromatography ◽  
Mean Concentration

Abstract Eight collaborators studied a fluoromelric and thin layer chromatographic method for aminacrine and its salts in powder and cream drug preparations. Recovery of aminacrine.HCI by fluorometer in both preparations averaged 100% for powder and 102% for cream. The mean concentration of aminacrine.HCI found in the powder was 0.108% with a standard deviation of ± 0.001%. The mean concentration of aminacrine found in the cream was 0.191% with a standard deviation of ± 0.003%. Seven of the 8 collaborators successfully used thin layer chromatography to identify the aminacrine in both sample forms supplied. The assay method for aminacrine and its salts in drug preparations is recommended for adoption as official, first action

scholarly journals Determination of trace elements in the plants of Mt. Bozdag, Izmir, Turkey

2010 ◽  
Vol 62 (3) ◽  
pp. 731-738 ◽  
Author(s):  
D. Yildiz ◽  
I. Kula ◽  
G. Ay ◽  
S. Baslar ◽  
Y. Dogan
Keyword(s):  
Trace Elements ◽  
Woody Plants ◽  
Statistical Significance ◽  
Absorption Spectrometry ◽  
Dry Weight ◽  
Current Level ◽  
The Mean ◽  
Herbaceous And Woody Plants ◽  
Made In

The aim of this study was to determine the current level of atmospheric heavy metal content on the Bozdag Mountain of the Aegean Region, Turkey. Twenty nine different plants were selected to study their potential as biomonitors of trace elements such as Ni, Zn, Fe, Pb, Mn and Cd (?g g-1, dry weight). The samples were collected from two different altitudes of Mt. Bozdag. The concentrations of trace elements were determined by atomic absorption spectrometry. The mean concentrations determined at 1000 m altitude ranged from 0.025 to 1.609, 0.232 to 0.731, 0.578 to 5.983, 0.287 to 0.565 and 0.176 to 2.659 (?g g-1, dry weight), for Ni, Zn, Fe, Pb and Mn, respectively. At the altitude of 1600 m, the values ranged from 0.023 to 0.939, 0.258 to 1.254, 0.839 to 5.176, 0.301 to 1.341 and 0.405 to 3.351 (?g g-1, dry weight) for Ni, Zn, Fe, Pb and Mn, respectively. No Cd was detected at either altitude. Statistical significance was determined by the independent sample t-test and comparisons were made in order to determine if there were any differences between the averages of herbaceous and woody plants. .

Comparison of Carbonate and Uricase-Carbonate Methods for the Determination of Uric Acid in Serum

1966 ◽  
Vol 12 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Wendell T Caraway ◽  
Herman Marable
Keyword(s):  
Uric Acid ◽  
The Mean ◽  
High Doses ◽  
Mean Concentration ◽  
Uricase Activity ◽  
Good Agreement

Abstract A colorimetric carbonate procedure for the determination of uric acid has been modified to include incubation of serum with uricase to destroy uric acid. Residual nonurate chromogens are subtracted from total chromogens to obtain the concentration of "true" uric acid. Result obtained by the carbonate and the uricase-carbonate methods were in good agreement. The mean concentration of nonurate chromogens in serum is approximately 2% of the true uric acid values. Recovery of uric acid added to serum is essentially quantitative. Formaldehyde markedly inhibits uricase activity and interferes with recoveries. The uricase-carbonate method is applicable to hemolytic serum and to serums from patients with uremia or those receiving high doses of salicylate in which excess concentrations of nonurate chromogens may be encountered.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

Analysis of Fat-Soluble Vitamins. XX. Determination of Vitamin D in Multivitamin Preparations. Second Collaborative Study

1978 ◽  
Vol 61 (3) ◽  
pp. 735-745
Author(s):  
Ellen J De Vries ◽  
Frits J Mulder ◽  
Ben Borsje
Keyword(s):  
Vitamin D ◽  
Vitamin A ◽  
Test Data ◽  
Vitamin D3 ◽  
Collaborative Study ◽  
Three Samples ◽  
The Mean ◽  
Fat Soluble Vitamins

Abstract The official first action method for determining vitamin D in multivitamin preparations was modified. The method was collaboratively studied by 7 laboratories, using 6 preparations in oil. The preparations consisted of vitamin D at various levels and at various ratios (in w/w) to vitamin A. Three samples contained cholecalciferol and 3 samples contained vitamin D3 from vitamin D3 resin. After outliers were eliminated by the Dixon test, data were analyzed and averages were compared with amounts of vitamin D known to be in each sample. For samples with vitamin D: vitamin A ratios of 1:0.5, 1:5, and 1:10, the mean vitamin D recoveries were 98.8, 94.6, and 90.7%, respectively. The method has been adopted as official final action.

Determination of Protein Nitrogen in Plants

1977 ◽  
Vol 60 (3) ◽  
pp. 590-593 ◽  
Author(s):  
T Powell Gaines
Keyword(s):  
Acetic Acid ◽  
Plant Tissue ◽  
Nonprotein Nitrogen ◽  
Protein Nitrogen ◽  
Aoac Method ◽  
The Mean

Abstract A method is described for determining protein nitrogen (PN) in plants. Plant tissue extracted with 0.5% acetic acid to remove nonprotein nitrogen (NPN) prior to Kjeldahl analysis gave results very close to true PN, whereas AOAC crude PN method 2.049 gave results much too high. True PN was determined as the mean of 3 independently derived values and was used as the basis for comparing the proposed PN method with AOAC method 2.049. Failure of the AOAC method to differentiate between NPN and/or inorganic ammoniacal N and actual PN causes values derived from this method to be too high when it was used to determine PN in plants.

Eutylone Intoxications—An Emerging Synthetic Stimulant in Forensic Investigations

2020 ◽  
Author(s):  
Alex J Krotulski ◽  
Donna M Papsun ◽  
Chris W Chronister ◽  
Joseph Homan ◽  
Michele M Crosby ◽  
...  
Keyword(s):  
Standard Deviation ◽  
The United States ◽  
Driving Under The Influence ◽  
Novel Psychoactive Substances ◽  
Psychoactive Substances ◽  
Manner Of Death ◽  
Clinical Investigations ◽  
The Mean ◽  
Forensic Investigations ◽  
Mean Concentration

ABSTRACT Synthetic stimulants are the largest class of novel psychoactive substances identified each year by forensic laboratories internationally. While hundreds of these drugs appear in drug powders, only a few proliferate in use among forensically relevant populations, eventually emerging in postmortem and clinical investigations. Beta-keto-methylenedioxyamphetamines (i.e., novel psychoactive substances with names ending in “ylone”) are currently the most popular subclass of synthetic stimulants. Leading up to its federal scheduling in 2018, N-ethyl pentylone was the most encountered synthetic stimulant. The popularity of N-ethyl pentylone declined once it was scheduled, but it was quickly replaced by eutylone (bk-EBDB), a structurally related analog from the same family. In cases encountered between January 2019 and April 2020, eutylone was quantitatively confirmed in 83 forensic investigations, including postmortem cases and driving under the influence of drugs cases. Matrix types included blood, urine and tissue. Eutylone was identified in cases submitted from 13 states, demonstrating proliferation around the United States; Florida accounted for 60% of the positive cases. The mean concentration of eutylone in postmortem blood was 1,020 ng/mL (standard deviation = ±2,242 ng/mL; median = 110 ng/mL, range = 1.2–11,000 ng/mL, n = 67). The mean concentration of eutylone in blood from driving under the influence of drugs cases was 942 ng/mL (standard deviation = ±1,407 ng/mL; median = 140 ng/mL, range = 17–3,600 ng/mL, n = 7). This report includes cause and manner of death data for 22 postmortem cases. Further analysis of authentic human specimens revealed the presence of three eutylone metabolites, including one unique biomarker and one metabolite in common with butylone. Laboratories should be aware that eutylone may be present in cases of suspected Ecstasy, “Molly” and/or methylenedioxymethamphetamine use, causing or contributing to impairment or death.

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Substitution of Cupric Sulfate for Mercuric Oxide as Catalyst for the Kjel-Foss Instrument

1976 ◽  
Vol 59 (1) ◽  
pp. 219-220
Author(s):  
Larry L Wall ◽  
Charles W Gehrke
Keyword(s):  
Standard Deviation ◽  
Mercuric Oxide ◽  
Experimental Sample ◽  
Cupric Sulfate ◽  
Protein Nitrogen ◽  
Feed Control ◽  
Relative Standard ◽  
Standard Configuration ◽  
Automated Instrument

Abstract A mixture of cupric sulfate and titanium dioxide and cupric sulfate alone were evaluated as possible catalysts to replace mercuric oxide in the determination of protein nitrogen, using the Kjel-Foss automated instrument. It was necessary to modify the instrument to increase the digestion time from 6 to about 12 min to achieve acceptable protein nitrogen recovery with cupric sulfate as the catalyst. An experimental sample set of nitrogen-containing salts and American Association of Feed Control Officials check feed samples were analyzed with the Kjel-Foss instrument in its standard configuration with mercuric oxide and as modified with cupric sulfate as the catalyst. The average per cent nitrogen, standard deviation, and relative standard deviation with mercuric oxide and cupric sulfate were 10.37 and 10.36, 0.040 and 0.042, and 0.53 and 0.56, respectively. The substitution of cupric sulfate for mercuric oxide is feasible, and it eliminates the use of the potential pollutant, mercury.

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