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.

An improved double antibody radioimmunoassay for the determination of insulin in serum, plasma, and tissue incubation media

1982 ◽  
Vol 60 (10) ◽  
pp. 962-966 ◽  
Author(s):  
Marthe Dalpé-Scott ◽  
H. M. C. Heick ◽  
Nicole Bégin-Heick
Keyword(s):  
Experimental Animals ◽  
Limited Size ◽  
Double Antibody ◽  
Incubation Periods ◽  
Free Insulin ◽  
Antibody Method ◽  
Nonspecific Interactions ◽  
Insulin Radioimmunoassay ◽  
Pig Serum

We have modified the double antibody method of insulin radioimmunoassay to allow relatively short incubation periods and the use of centrifugation to separate bound from free insulin. This was achieved by altering the order of addition of reagents and by adding normal guinea-pig serum to reduce nonspecific interactions. The method allows for precise measurements in the range of 0–3.2 ng insulin. Both serum and plasma give consistent values. The technique is useful for the measurement of insulin levels in samples of limited size such as those from small experimental animals.

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. I. Demonstration of resistance to reinfection using a model system that involves perfusion of mice within three weeks of challenge

1978 ◽  
Vol 52 (3) ◽  
pp. 173-186 ◽  
Author(s):  
M. Doenhoff ◽  
Q. Bickle ◽  
E. Long ◽  
J. Bain ◽  
A. McGregor
Keyword(s):  
Schistosoma Mansoni ◽  
Primary Infection ◽  
Model System ◽  
Challenge Infection ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Challenge Control ◽  
Excretion Rates ◽  
Homologous Challenge

ABSTRACTThe degree of resistance acquired by Schistosoma mansoni-infected mice against homologous challenge has been determined by perfusion of the animals within three weeks of the challenge, at which time the challenge-derived organisms were morphologically distinguishable from the primary infection which induced the resistance. The method has been compared with assays based on determination of the number of organisms migrating through the lung, and with perfusions at a later time when the challenge has matured. The results obtained with the three week perfusion method, showing that resistance was acquired by eight weeks after a primary infection, were confirmed by the longer survival of, and reduced egg excretion rates and tissue egg burdens in the experimental animals relative to respective challenge control animals. However, some discrepancy in challenge-derived worm numbers was found between animals perfused three weeks after challenge and those autopsied at later times. The possible reasons for this difference are discussed. The degree of resistance that was acquired was to some extent dependent on the size of the challenge infection.

Factors Affecting the Determination of Citrate-Insoluble Phosphorus

1982 ◽  
Vol 65 (3) ◽  
pp. 655-658
Author(s):  
Frank J Johnson ◽  
James A Farley
Keyword(s):  
Bath Temperature ◽  
Official Method ◽  
Triple Superphosphate ◽  
Sample Weight ◽  
Ground Sample ◽  
Factors Affecting ◽  
Insoluble Phosphorus ◽  
Aoac Official ◽  
Preparation Techniques

Abstract Interlaboratory imprecision of results for citrate-insoluble P2O5 is greater than desired, especially for analyses of triple superphosphate (TSP). A systematic study of the method indicates that the most significant contributor to the imprecision is the fineness of the ground sample. Other factors affecting results are sample weight, bath temperature, and extraction time. Comparable results are reported for TSP analyzed by the AOAC official method on samples prepared by grinding to –20 + 200 mesh, on unground samples, and on samples disintegrated by an ultrasonic bath. Similar tests on diammonium phosphate, using the same 3 sample preparation techniques, yield results that are not comparable.

Spectrophotometric Determination of Factor Xa Generation in Factor IX Concentrates

1977 ◽  
Vol 37 (03) ◽  
pp. 535-540 ◽  
Author(s):  
D. S Pepper ◽  
D Banhegyi ◽  
Ann Howie
Keyword(s):  
Intrinsic Factor ◽  
Factor Xa ◽  
Factor Ix ◽  
Factor V ◽  
Factor X ◽  
Generation Times ◽  
Incubation Periods ◽  
Multiple Sample ◽  
Recording Spectrophotometer

SummaryPrevious work from this department, concerned with testing the potential thrombogenicity of therapeutic factor IX concentrates, demonstrated that following recalcification of factor IX concentrates thrombin was generated within 3-30 minutes of incubation (Sas et al. 1975). The test developed (known as the TGt 50 test) is a two-stage assay and was thus found to be time consuming, tedious and tended to become inaccurate with long incubation periods and a large number of samples. A semiautomatic version of the test is reported in which the synthetic peptide Bz-ILE-GLU-GLY-ARG-pNA (S-2222) is added to recalcified, diluted factor IX concentrate in the micro-cuvette of a multiple sample recording spectrophotometer. Information can be obtained on (a) the amount of Xa (if any) present prior to recalcification (b) the initial amount of Xa formed and (c) the time taken to activate all factor X to Xa. Direct graphical interpretation shows a number of qualitative differences between commercial preparations, but by either of the criteria (b) or (c) above, it is possible to place the different products into “activated” and “non activated” groups such that both the Xa generation times and TGt 50 tests identify the same two groups of products. This agreement also indicates that the TGt 50 test is independent of the intrinsic factor V levels in the various concentrates.

Determination of the most significant factors affecting the life of tires and gear motor-wheels using a priori ranking

2019 ◽  
Vol 12 (48) ◽  
pp. 3-10
Author(s):  
E.K. Abdulaev ◽  
◽  
P.N. Maharathis ◽  
A.I. Kuzhelev ◽  
◽  
...  
Keyword(s):  
A Priori ◽  
Factors Affecting ◽  
Significant Factors

Modeling of dynamic mosaicism on ring chromosomes in human fibroblasts and IPSCS

2020 ◽  
pp. 12-13
Author(s):  
Т.В. Никитина ◽  
А.А. Кашеварова ◽  
М.М. Гридина ◽  
А.А. Хабарова ◽  
А.Г. Мензоров ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Human Fibroblasts ◽  
Cellular Heterogeneity ◽  
Mitotic Stability ◽  
Factors Affecting ◽  
Ring Chromosomes ◽  
Cell Clones ◽  
Mitotic Instability ◽  
Mitotic Behavior

Митотическая нестабильность кольцевых хромосом может приводить к появлению клеточных клонов с различной генетической структурой. В качестве модели нестабильности кольцевых хромосом в митозе мы использовали фибробласты от пациентов с r(8), r(13), r(18) и r(22) и полученные из них индуцированные плюрипотентные стволовые клетки (ИПСК). Линии ИПСК с r(22) имели относительно стабильный кариотип на протяжении десятков (до 60) пассажей и сохраняли неизменную структуру кольцевой хромосомы. Кариотип линий ИПСК с r(8) и r(18) на ранних пассажах стабильный, планируется его изучение на поздних пассажах. Наибольшее разнообразие кариотипа выявлено в линиях ИПСК с r(13), в которых наблюдали различные перестройки и выраженную клеточную гетерогенность. Определение факторов, влияющих на митотическую стабильность кольцевых хромосом, может иметь значение для консультирования пациентов. Mitotic instability of ring chromosomes can lead to the appearance of cell clones with different genetic structure. IPSCs from fibroblasts of patients with r(8), r(13), r(18), and r(22) were used as a model of ring chromosomes mitotic behavior. Karyotypes of iPSC lines with r(8) and r(18) have so far been evaluated only in the early passages, lines with r(22) have maintained a relatively stable karyotype up to 60 passages. The occurrence of rearrangements and cellular heterogeneity was found characteristic for r(13) iPSCs. The determination of factors affecting the ring chromosomes mitotic stability would be beneficial for the patient’s prognosis.

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