scholarly journals CELL POPULATION CHANGES IN THE INTESTINAL MUCOSA OF PROTEIN-DEPLETED OR STARVED RATS

1972 ◽  
Vol 53 (1) ◽  
pp. 225-230 ◽  
Author(s):  
A. F. Hopper ◽  
P. M. Rose ◽  
R. W. Wannemacher
Keyword(s):  
Population Changes ◽  
Time Rate ◽  
Maturation Period ◽  
Cell Cycle Time ◽  
Rat Ileum ◽  
Experimental Animals ◽  
Time Required ◽  
Protein Free Diet ◽  
Migration Of Cells

The effect of protein-free and starvation diets on the migration of cells from the crypts onto and up the villi of the rat ileum was studied. Rats starved for 3, 7, or 10 days or fed a protein-free diet (PFD) for 3, 7, or 11 wk were injected with thymidine-3H and sacrificed at timed intervals. The time required for the labeled cells to first appear on the villi of experimental animals was longer than in the controls. This was the result of an elongated cycle in the protein-depleted animals and a lengthening of the maturation period in both the starved and protein-depleted animals. Determination of the distance which labeled cells had migrated up the villi in control and experimental animals, after thymidine-3H injection, indicated that cells in animals starved for 7 days migrated more rapidly than those in the fed controls, while those of 10-day starved animals moved more slowly. The cells of animals fed PFD for 3 wk migrated up the villi more rapidly, those of animals depleted for 7 wk migrated at the same time rate, and those of 11-wk PFD animals migrated more slowly than the fed controls. There is apparently no correlation between the cell cycle time in the crypt cells and the rate of migration of cells up the villus.

scholarly journals CELL POPULATION CHANGES IN THE INTESTINAL MUCOSA OF PROTEIN-DEPLETED OR STARVED RATS

1971 ◽  
Vol 50 (3) ◽  
pp. 887-892 ◽  
Author(s):  
P. M. Rose ◽  
A. F. Hopper ◽  
R. W. Wannemacher
Keyword(s):  
Cell Cycle ◽  
Intestinal Mucosa ◽  
Cycle Time ◽  
Population Changes ◽  
Relative Duration ◽  
Cell Cycle Time ◽  
Large Variability ◽  
Control Value ◽  
Protein Free Diet ◽  
Synthetic Phase

The effect of a protein-free diet and starvation on the duration of the rat ileal crypt cell cycle time was studied by Quastler's technique of labeled mitoses. Rats were fed a protein-free diet for 3, 7, or 11 wk or were starved for 7 or 10 days. Progressive protein depletion resulted in a progressive lengthening of the cycle time (GT), due primarily to a lengthening of the synthetic phase (S) of the cycle. The presynthetic gap (G1) was the same as the control value after 3 wk and lower, but not significantly so, due to the large variability, after 11 wk. The duration of the postsynthetic gap (G2) plus mitotic phase (M) was not affected by the diet. As the dietary stress became more severe, the cell cycle also became more variable. Although the GT of rats starved for as long as 10 days was only slightly different from the control, the relative duration of the components of the cycle changed significantly. S and G2 were longer in the starved animals while G1 was of shorter duration.

Mercury-204 Determination by Emission Spectroscopy

1965 ◽  
Vol 19 (3) ◽  
pp. 87-89 ◽  
Author(s):  
F. M. Smith
Keyword(s):  
Coefficient Of Variation ◽  
Isotope Shift ◽  
Emission Spectroscopy ◽  
Electrodeless Discharge ◽  
Discharge Lamp ◽  
Isotope Concentration ◽  
Single Determination ◽  
Time Required

The determination of mercury-204 was made by using the isotope shift of the 3984 A mercury line excited by electrodeless discharge. Densitometric traces were made from film recordings of the 3984 A line and the areas under the component peaks were determined. Ratios of each of these areas to the sum of the areas from all the line components are plotted against the isotope concentration to produce a working curve. The coefficient of variation for this method is approximately 11 percent The time required for a single determination (after fabrication of the discharge lamp) is about two hours.

scholarly journals THE EFFECTS ON BIOLOGICAL MATERIALS OF FREEZING AND DRYING BY VACUUM SUBLIMATION

1954 ◽  
Vol 100 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Donald Greiff ◽  
Henry Pinkerton
Keyword(s):  
Influenza Virus ◽  
Biological Materials ◽  
Continuous Operation ◽  
Virus Suspension ◽  
Vacuum Sublimation ◽  
End Point ◽  
Different Temperatures ◽  
Time Required

A vacuum sublimation apparatus is described which will permit, (a) the removal of water from virus suspensions at temperatures ranging down to –80°C., (b) continuous operation with a minimum of attention from the investigator, (c) sealing off of samples at operating pressures (10–5 mm. Hg), (d) simultaneous lyophilization of aliquot samples at different temperatures, (e) isolation of a portion of the apparatus without disturbing the remainder of the system, and (f) determination of the end-point of sublimation without disturbing the samples. The time required for drying 0.1 ml. of influenza virus suspension was shown to increase markedly with decrease of temperature, 8 days being required for dehydration at –80°C. in contrast to 2 days at –30°C. and 1 day at 0°C.

scholarly journals The nylon bag technique in the determination of ruminal feed protein degradation

1983 ◽  
Vol 55 (1) ◽  
pp. 1-78 ◽  
Author(s):  
Jouko Setälä
Keyword(s):  
Particulate Matter ◽  
Pore Size ◽  
Control Sample ◽  
Sample Treatment ◽  
Sample Weight ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Incubation Periods ◽  
Feed Protein

The investigation included experiments in which factors affecting the reliability of the nylon bag method were studied. The possibility of applying the feed protein degradabilities to practical feeding conditions was also examined. In the experiments concerning reliability, such factors as bag porosity, sample weight, sample treatment, washing procedure, diets, and differences between animals and incubation days were studied. The feed protein degradabilities were also determined by using as incubation periods the ruminal retention times for particulate matter of different feeds, evaluated as a function of DM intake/100 kg liveweight in different diets. A nylon bag, with a pore size of 40 µm and internal dimensions of 6 X 12 cm was selected for the degradability determinations. The sample weight used in incubations was 57 —60  mg DM/cm2. In the determination of feed protein degradability, when sheep are used as experimental animals, it is recommended that for routine determinations only one animal be used, analyzing the contents of two bags for each incubation period during two successive days. A control sample of which degradability is determined in advance in many sheep, should be used in all incubations in order to control the digestive processes in the rumen of the experimental sheep. The actual degradabilities analyzed by the bag method are applicable in practise, if they are determined using animals at similar feeding levels and on diets similar to those prevailing under the conditions in which the degradabilities are going to be used.

scholarly journals Effect of packing on changes in erythrocyte osmotic fragility and malondialdehyde concentration in donkeys administered with ascorbic acid

2012 ◽  
Vol 79 (1) ◽  
Author(s):  
Folashade Olaifa ◽  
Joseph O. Ayo ◽  
Suleiman F. Ambali ◽  
Peter I. Rekwot
Keyword(s):  
Oxidative Stress ◽  
Ascorbic Acid ◽  
Osmotic Fragility ◽  
Blood Samples ◽  
Experimental Animals ◽  
Erythrocyte Osmotic Fragility ◽  
Nacl Concentration ◽  
Experimental Subjects ◽  
Apparently Healthy

Experiments were performed with the aim of investigating the effect of packing on erythrocyte osmotic fragility (EOF) and malondialdehyde (MDA) concentration in donkeys, and the effect of ascorbic acid (AA). Twelve apparently healthy donkeys raised under the traditional extensive system served as experimental subjects. Six donkeys administered orally with AA (200 mg/kg) and subjected to packing were used as experimental animals, whilst six others not administered with AA served as controls. Blood samples were collected pre- and post-packing from all the donkeys for the determination of MDA and EOF. At 0.3% Sodium Chloride (NaCl) concentration, the percentage haemolysis was 93.69% ± 2.21% in the control donkeys and the value was significantly (P < 0.05) higher than the value of 71.31% ± 8.33%, recorded in the experimental donkeys. The post-packing MDA concentration obtained in the control donkeys was 39.62 µmol ± 4.16 µmol, and was not significantly different (P > 0.05) from the value of 35.97 µmol ± 2.88 µmol recorded in the experimental donkeys. In conclusion, the increase in haemolysis obtained in the donkeys suggested that packing induced oxidative stress, which was ameliorated by AA administration.

Genotype and environment in the determination of minor skeletal variants and body weight in mice

Development ◽  
1967 ◽  
Vol 17 (2) ◽  
pp. 283-292
Author(s):  
W. L. Howe ◽  
P. A. Parsons
Keyword(s):  
Maternal Age ◽  
Maternal Diet ◽  
Heterogeneous Material ◽  
Inbred Strains ◽  
Relative Importance ◽  
Maternal Weight ◽  
Detailed Understanding ◽  
Experimental Animals ◽  
Percentage Incidence

Numerous minor skeletal variants have been described in the mouse (Grüneberg, 1963), other small mammals (Berry & Searle, 1963) and in man (Comas, 1960; Brothwell, 1963; Grüneberg, 1963). In genetically heterogeneous material such as man it is very difficult to sort out the factors causing these variants. However, in experimental animals such as the mouse the use of inbred strains and crosses derived from them permits a more detailed understanding of these factors, in particular the relative importance of heredity and environment. Grüneberg (1963) cites numerous references showing very great differences in the percentage incidence of many minor variants in mice between inbred strains and in some cases between hybrids. The conclusion is that much of this variation is genetic in origin. Even so, certain environmental factors have been shown to be of importance, such as maternal age, parity, maternal weight and maternal diet.

scholarly journals Comparison of the isotope dilution method for determination of the ileal endogenous amino acid losses with labelled diet and labelled pigs

2000 ◽  
Vol 83 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Vincent Hess ◽  
Philippe Ganier ◽  
Jean-Noel Thibault ◽  
Bernard Sève
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Latin Square ◽  
Isotope Dilution Method ◽  
Dilution Method ◽  
First Case ◽  
Endogenous Protein ◽  
The Individual ◽  
Protein Free Diet

The aims of the present study were first to compare the amino acid dilution method performed using labelled animals with that using labelled diets, and second to determine real digestibilities and total ileal endogenous losses of N and amino acids. Two diets containing pea cultivars (Solara and Amino) and a protein-free diet were compared in a 3 × 3 Latin-square experiment. The three pigs were each prepared with an ileo-rectal anastomosis and were continuously infused with [1-13C]leucine. For each cultivar,15N-labelled and unlabelled diets were formulated. The real digestibility and endogenous losses of leucine were higher when obtained by labelling the pig than by labelling the foodstuff. This was due either to the inadequate estimation of the endogenous protein enrichment in the first case or to the importance of dietary N recycling in the second case. However, in both cases the ileal endogenous losses of N and amino acids were higher than the basal losses determined with the protein-free diet. There were significant differences between the two pea cultivars in terms of phenylalanine and leucine when measured with labelled diets. It is suggested that, although ileal endogenous losses may be underestimated, using labelled feedstuffs is of great interest due to the direct estimation of the individual amounts of amino acids.

Rapid Measurement of Nutation NQR Spectra in Powders Using an RF Pulse Train

1996 ◽  
Vol 51 (5-6) ◽  
pp. 363-367 ◽  
Author(s):  
Nicolai Sinyavsky ◽  
Michał Ostafin ◽  
Mariusz Maćkowiak
Keyword(s):  
Asymmetry Parameter ◽  
Pulse Train ◽  
Pulse Action ◽  
Rf Pulses ◽  
Time Saving ◽  
Long Time ◽  
The Asymmetry ◽  
Rf Pulse ◽  
Time Required

Abstract The method of two-dimensional nutation NQR spectroscopy, introduced by Harbison in 1989, has been successfully used for determining of the asymmetry parameter of the EFG tensor for spin-3/2 nuclei in both powdered and monocrystal samples in the absence of an external magnetic field. The inconvenience inherent in the method, however, is the long time required, because data acquisition must be repeated for various RF pulse lengths. We discuss a method to reduce the time of the nutation experiment by using a sequence of identical short RF pulses of length r w and distance τ. It is shown that for an NQR frequency ω0 , frequency offset Δω, and pulse parameters satisfying the relation ω0τ + Δωtw = 2πk (k = 1, 2, 3,..., n) a synchronism of pulse action takes place and the nutation interferogram can be measured "stroboscopically" between the pulses. The maximum time saving factor that can be obtained as compared to the conventional nutation experiment is of the order of the number of pulses used in a pulse train. The method has been successfully applied for determination of the asymmetry parameter for one of the two 3 5 Cl sites in polycrystalline 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride).

DETERMINATION OF URANIUM IN FLOTATION CONCENTRATES AND IN LEACH LIQUORS BY X-RAY FLUORESCENCE

1959 ◽  
Vol 37 (1) ◽  
pp. 20-28 ◽  
Author(s):  
G. L. Smithson ◽  
R. L. Eager ◽  
A. B. VanCleave
Keyword(s):  
Direct Measurement ◽  
Pilot Plant ◽  
Internal Standard ◽  
Liquid Extraction ◽  
X Ray ◽  
Liquid Liquid Extraction ◽  
Northern Saskatchewan ◽  
Plant Operations ◽  
Time Required

X-Ray fluorescence has been applied to the analysis of flotation concentrates obtained from pegmatitic uranium ores occurring in Northern Saskatchewan. Approximate uranium analyses can be obtained by direct measurement on flotation concentrates but more accurate results are obtained by using an internal standard such as strontium or yttrium. The time required for an analysis, as compared to that of conventional chemical or fluorimetric methods, is considerably reduced and flotation pilot plant operations can therefore be more effectively controlled. The method has been extended to include the analysis of sulphate leach liquors obtained from the leaching of pegmatitic ores and their flotation concentrates. Organic phases obtained in liquid – liquid extraction studies can also be rapidly analyzed for uranium by X-ray fluorescence.

scholarly journals XXXIII.—I. On the Estimation of Carbon in Organic Substances by the Kjeldahl Method. II. Its Application to the Analysis of Potable Waters

1895 ◽  
Vol 37 (4) ◽  
pp. 743-757
Author(s):  
Charles Hunter Stewart
Keyword(s):  
Accurate Method ◽  
Great Accuracy ◽  
Organic Substances ◽  
Applied Chemistry ◽  
Carbon And Nitrogen ◽  
Kjeldahl Method ◽  
The Will ◽  
Time Required

An easy and yet accurate method of determining carbon and nitrogen in organic substances has long been a desideratum, especially among those engaged in the application of chemistry to biological, hygienic, and agricultural questions. For the determination of nitrogen the method of Dumas, with its numerous modifications, is still the only one applicable in all cases, but the time required for it, and the manipulative dexterity necessary, has prevented its wide application for the above-named purposes. The method of Will and Varrentrap, though less generally applicable, is easier, and, until the publication of Kjeldahl's method, was most frequently used in applied chemistry. Kjeldahl claims for his method the same applicability and as great accuracy as the Will and Varrentrap method, with the added advantage of greater ease in working.

Sign in / Sign up

Export Citation Format

Share Document