scholarly journals Variation between sheep in renal excretion of [14C]allantoin

2002 ◽  
Vol 87 (6) ◽  
pp. 561-568 ◽  
Author(s):  
P. Prasitkusol ◽  
E. R. Ørskov ◽  
X. B. Chen ◽  
F. D. DeB. Hovell ◽  
D. J. Kyle
Keyword(s):  
Filtration Rate ◽  
Renal Excretion ◽  
Mean Value ◽  
Purine Derivatives ◽  
Individual Values ◽  
Simple Alternative ◽  
Micro Organisms ◽  
Accuracy Of Prediction

The objectives of the present study were to investigate the recovery of [14C]allantoin in urine of sheep dosed intravenously and degradation of allantoin by rumen micro-organisms. The recovery of [14C]allantoin in the urine of eight sheep was measured during three periods in two experiments. Individual values of [14C]allantoin recovery varied from 66 to 95 % (mean value 83 (SE 1·6) %). The recovery of [14C]allantoin showed no relation to the level of feed intake. There was some evidence that glomerular filtration rate was an important factor affecting the amount of urinary allantoin recovered in one experiment. Incomplete recovery of plasma [14C]allantoin in the urine indicated losses of plasma [14C]allantoin via non-renal routes. This is supported by the disappearance of14C from rumen contents incubatedin vitrowith [14C]allantoin for 48 h (88 %) and the presence of14C in salivain vivofrom sheep sampled after dosing with [14C]allantoin. However, the amount of14C activity in the saliva was very low (equivalent to only 1·5 % of the total dose in sheep producing saliva at a rate of 15 litres/d). The proportion of renal and non-renal excretion of purine derivatives was found to be unpredictable both between and within individual animals. The factors responsible for this variability need to be identified, and existing models of excretion of purine derivatives may need to be modified accordingly to improve their accuracy of prediction. A single intravenous injection of [4,5-14C]allantoin provides a simple alternative to infusion methods used to measure the proportion of plasma allantoin excreted in the urine of sheep. Using this method it may be feasible to validate PD excretion models in other ruminant livestock.

Assembly of three major subclasses of mouse immunoglobulin G: a theoretical model for covalent assembly in vivo

1976 ◽  
Vol 54 (8) ◽  
pp. 688-698 ◽  
Author(s):  
J. R. Percy ◽  
M. E. Percy ◽  
R. Baumal
Keyword(s):  
Cell Lines ◽  
Immunoglobulin G ◽  
Mean Value ◽  
Individual Values ◽  
In Vitro Assembly ◽  
The Mean ◽  
The Individual ◽  
Mouse Myeloma

A mathematical model, based on second-order reaction kinetics, has been used to describe the covalent assembly of immunoglobulin G (IgG) in vitro from its heavy (H) and light (L) chains (Percy, M. E., Baumal, R., Dorrington, K. J. &Percy, J. (1976) Can. J. Biochem. 54, 675–687). In the present paper, the same model has now been applied to the steady-state assembly of IgG in vivo. This mathematical approach permits a quantitative comparison of the pathways of covalent assembly used by given immunoglobulins in vivo and in vitro. The assumptions in the model are: the species L, H, HL, HH, HHL and LHHL belong to a common pool; incompleted IgG intermediates may freely assemble to form HL, HH, HHL and LHHL; the reaction rate for covalent linkage between any two reacting species is proportional to the products of the number densities of the reactants and to a parameter P which takes the value PHH if the reaction joins two H chains, and PHL if it joins an H and L chain. In vivo values of PHH/PHL were determined for the 18 mouse myeloma tumours and cell lines studied by Baumal et al. (Baumal, R., Potter, M. &Scharff, M. (1971) J. Exp. Med. 134, 1316–1334). From these analyses, we have arrived at the following conclusions: (1) the three major IgG subclasses have distinctive values of PHH/PHL (mean value 53 for IgG1, 12 for IgG2a and 2.8 for IgG2b); (2) for IgGs of the same subclass, the values of PHH/PHL are similar; (3) the mean in vivo values of PHH/PHL are very close to those determined from in vitro assembly experiments. Finally, the individual values of PHH/PHL have been used to simulate pulse-chase experiments in the various tumours and cell lines. Considering the sources and magnitude of experimental error, the theoretical pathways of assembly agree with those determined qualitatively from the pulse-chase experiments.

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

Anaerobes in ejaculates of subfertile men

1995 ◽  
Vol 1 (5) ◽  
pp. 462-478 ◽  
Author(s):  
Waltraud Eggert-Kruse ◽  
Gerhard Rohr ◽  
Wolfram Ströck ◽  
Susanne Pohl ◽  
Beate Schwalbach ◽  
...  
Keyword(s):  
Tract Infection ◽  
Genital Tract ◽  
Anaerobic Bacteria ◽  
Cervical Mucus ◽  
Anaerobic Growth ◽  
Pathogenic Species ◽  
Genital Tract Infection ◽  
Micro Organisms

Abstract The clinical significance of micro-organisms in semen samples of asymptomatic subfertile patients is a matter of constant debate. Usually little attention is paid to anaerobic bacteria as they are sensitive to transportation and culturing, and differentiation is difficult, costly and time-consuming. In the present study, special screening was carried out for anaerobes in ejaculates in addition to the routine microbial cultures of genital secretions of both partners. In addition to standard semen analysis and evaluation of sperm ability to penetrate cervical mucus (CM) in vivo (postcoital testing) and in vitro using a standardized test system, semen samples from 126 randomly chosen males of couples with a median duration of infertility of 4 years were examined for colonization with anaerobic bacteria. All couples were without clinical signs or symptoms of genital tract infection. The special care taken for anaerobic growth in semen samples gave a high rate of positive cultures and showed that nearly all ejaculates (99%) were colonized with anaerobic micro-organisms, and potentially pathogenic species were found in 71% of men. This rate was more than four times higher than that obtained with routine cultures and standard transportation (16%). Anaerobic bacterial growth of ≥106 colony forming units (CFU)/ml was seen in 42% (total range 103-108 CFU/ml). In addition, aerobic growth was found in 96%(≥106 CFU/ml in 21%), potentially pathogenic species in 61% of semen specimens. There were no marked differences in the prevalence of anaerobic micro-organisms in patients with reduced or normal sperm count, motility or morphology. Nor was there any significant difference in anaerobic colonization between samples with impaired or good ability to penetrate CM of female partners (in vivo or in vitro), or the CM of fertile donors in the in-vitro sperm-cervical mucus penetration test (SCMPT) in this asymptomatic group of patients. There was no clear association between microbial colonization and subsequent fertility in vivo within an observation period of 6 months. The results of this study suggest that anaerobic bacteria are often not detected when routine methods for microbial evaluation are used. This should be considered during assisted reproduction and in patients with symptoms of genital tract infection and should lead to further studies in infertile patients where subclinical infection or inflammation is indicated by specific markers in semen samples.

scholarly journals Increased activity of indoleamine 2,3-dioxygenase in serum from acutely infected dengue patients linked to gamma interferon antiviral function

2009 ◽  
Vol 90 (4) ◽  
pp. 810-817 ◽  
Author(s):  
Aniuska Becerra ◽  
Rajas V. Warke ◽  
Kris Xhaja ◽  
Barbara Evans ◽  
James Evans ◽  
...  
Keyword(s):  
Antiviral Effect ◽  
Denv Infection ◽  
Gamma Interferon ◽  
Indoleamine 2,3 Dioxygenase ◽  
Inhibition Of Growth ◽  
Healthy Donors ◽  
Antiviral Function ◽  
Micro Organisms

The depletion of l-tryptophan (L-Trp) has been associated with the inhibition of growth of micro-organisms and also has profound effects on T cell proliferation and immune tolerance. The enzyme indoleamine 2,3-dioxygenase (IDO) catalyses the rate-limiting step in the catabolic pathway of L-Trp. Gene expression analysis has shown upregulation of genes involved in L-Trp catabolism in in vitro models of dengue virus (DENV) infection. To understand the role of IDO during DENV infection, we measured IDO activity in sera from control and DENV-infected patients. We found increased IDO activity, lower levels of L-Trp and higher levels of l-kynurenine in sera from DENV-infected patients during the febrile days of the disease compared with patients with other febrile illnesses and healthy donors. Furthermore, we confirmed upregulation of IDO mRNA expression in response to DENV infection in vitro, using a dendritic cell (DC) model of DENV infection. We found that the antiviral effect of gamma interferon (IFN-γ) in DENV-infected DCs in vitro was partially dependent on IDO activity. Our results demonstrate that IDO plays an important role in the antiviral effect of IFN-γ against DENV infection in vitro and suggest that it has a role in the immune response to DENV infections in vivo.

Substrate utilization and oxygen consumption by canine jejunal mucosa in vitro

1975 ◽  
Vol 229 (1) ◽  
pp. 139-143 ◽  
Author(s):  
RG Lester ◽  
E Grim
Keyword(s):  
Oxygen Consumption ◽  
Carbon Dioxide Production ◽  
Substrate Utilization ◽  
Mean Value ◽  
Jejunal Mucosa ◽  
Single Animal ◽  
Endogenous Substrate ◽  
Time Basis

Oxygen consumption, carbon dioxide production, and substrate utilization by small pieces of canine jejunal mucosa have been measured in vitro. In the absence of added substrate, the Qo2 was 0.21 mumol/h per mg dry wt and the respiratory quotient (RQ) was 0.73 indicating the endogenous substrate to be lipid in nature. When glucose or galactose was added, Qo2 and RQ increased. Metabolism of the endogenous substrate was depressed by fructose but not by glucose or galactose. Less than 15% of the metabolized glucose and fructose was degraded to Co2; 80% of the metabolized glucose was recovered as lactate. Galactose disappeared at one-seventh the rate of glucose, but 40% of that metabolized was degrated to CO2. In all experiments Qo2 showed marked cyclic fluctuations with an amplitude of 30-40% of the mean value and a period of 30-40 min. For tissues from a single animal, the cycles were in phase on a clock time basis, indicating that the cycles were synchronized by some in vivo mechanism.

Integration of in vitro parameters by mechanistic modelling to predict recycling of microbial nitrogen in the rumen

1998 ◽  
Vol 22 ◽  
pp. 158-160
Author(s):  
J. Dijkstra ◽  
J. France ◽  
S. Tamminga
Keyword(s):  
Bacterial Protein ◽  
Protein Breakdown ◽  
Microbial Protein ◽  
Evaluation Systems ◽  
Microbial Nitrogen ◽  
Substrate Conversion ◽  
Micro Organisms ◽  
Protein Supply

In protein evaluation systems for ruminants, the microbial protein supply is calculated from the amounts of rumen degradable organic matter and nitrogen (N) using empirical equations. A variable part of the rumen synthesized microbial protein does not reach the duodenum but is recycled within the rumen (review Firkins, 1996). Since energy is required for its re-synthesis and degraded microbial protein is subject to deamination, the efficiency of substrate conversion into microbial protein in the rumen is affected by microbial recycling. Rumen protozoa have a major impact upon this recycling through engulfment of micro-organisms and autolysis. In vitro, bacterial protein breakdown is proportionately reduced by some 0·9 upon removal of protozoa (Wallace and McPherson, 1987). Defaunation of the rumen increases the efficiency of microbial protein synthesis in vivo significantly (review Jouany et al., 1988).

Diuretic and natriuretic properties of prestegane B, a mammalian lignan

1987 ◽  
Vol 253 (2) ◽  
pp. R375-R378
Author(s):  
G. E. Plante ◽  
C. Prevost ◽  
A. Chainey ◽  
P. Braquet ◽  
P. Sirois
Keyword(s):  
Glomerular Filtration Rate ◽  
Filtration Rate ◽  
Urine Flow ◽  
In Vivo Model ◽  
Similar Magnitude ◽  
Site Of Action ◽  
Normal Rat ◽  
Natriuretic Effect

The effect of increasing doses of prestegane B, a synthetic lignan, was examined in the anesthetized normal rat, using clearance methodology. Increasing doses of prestegane B 0.5, 1.0, 2.0, and 5.0 mg) were administered intravenously in our separate groups of hydropenic rats. Urine flow increased by 2.8 +/- 0.3, 4.5 +/- 0.5, 7.7 +/- 0.5, and 18.2 +/- 0.8 microliters/min, respectively, above control values. The rise of urinary sodium secretion was of similar magnitude and averaged 0.4 +/- 0.1, 0.8 +/- 0.2, 1.1 +/- 0.3, and 2.4 +/- 0.3 mu eq/min, respectively. No significant change in urinary phosphate excretion was obtained in all groups of rats, and glomerular filtration rate remained constant from control to experimental clearance periods. The natriuretic effect of prestegane B observed in this in vivo model could be related to the inhibition of the Na+-K+-adenosine triphosphate activity demonstrated in vitro in previous studies from our laboratory. The action of this substance is likely to be situated beyond the proximal tubule, since urinary phosphate was not altered. Prestegane B mimics the effects of other endogenous diuretic and natriuretic hormones, but its site of action and its effect on renal hemodynamics are obviously different.

Repeatability of in vitro digestibility assays of forages when using fresh, frozen or freeze-dried cow faeces instead of sheep rumen liquor as sources of micro-organisms

1995 ◽  
Vol 1995 ◽  
pp. 110-110 ◽  
Author(s):  
S Akhter ◽  
E Owen ◽  
M K Theodorou ◽  
S L Tembo ◽  
E R Deaville
Keyword(s):  
Freeze Drying ◽  
Rumen Fluid ◽  
In Vitro Digestibility ◽  
Two Stage ◽  
Freeze Dried ◽  
Fresh Frozen ◽  
Sheep Rumen ◽  
Micro Organisms

Previous studies (El Shaer, Omed and Axford, 1987; Akhter, Owen, Fall, O'Donovan and Theodorou, 1994) with the two-stage in vitro procedure of Tilley and Terry (1963) have shown a high correlation between digestibilities of forages as determined using either sheep rumen liquor, sheep faeces or cow faeces as the microbial inoculum. In the first study of the of the present investigation one objective was to examine the repeatability of these digestibility measurements when made on different occasions. A second objective was to assess whether the correlations between faecal and rumen fluid based inocula could be improved if microorganisms were obtained from pairs rather than individual animals. The objective in the second study using forages of known in vivo digestibility, was to investigate the effect of freezing or freeze-drying of faeces on the repeatability of digestibilities of forages determined in vitro using micro-organisms from cow faeces.

scholarly journals Sites of methylation of purified transfer ribonucleic acid preparations by enzymes from normal tissues and from tumours induced by dimethylnitrosamine and 1,2-dimethylhydrazine

1974 ◽  
Vol 137 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Anthony E. Pegg
Keyword(s):  
Rat Kidney ◽  
Trna Sequence ◽  
Normal Tissues ◽  
Mouse Colon ◽  
Mammalian Tissues ◽  
Trna Species ◽  
Micro Organisms ◽  
Methylase Activity

1. The sites within the tRNA sequence of nucleosides methylated by the action of enzymes from mouse colon, rat kidney and tumours of these tissues acting on tRNAAsp from yeast and on tRNAGlu2, tRNAfMet and tRNAVal1 from Escherichia coli were determined. 2. The same sites in a particular tRNA were methylated by all of these extracts. Thus tRNAGlu2 was methylated at the cytidine residue at position 48 and the adenosine residue at position 58 from the 5′-end of the molecule; tRNAAsp was methylated at the guanosine residue at position 26 from the 5′-end of the molecule; tRNAfMet was methylated at the guanosine residues 9 and 27, the cytidine residue 49 and the adenosine residue 59 from the 5′-end; tRNAVal1 was methylated at the guanosine residue 10, the cytidine residue 48 and the adenosine residue 58 from the 5′-end. 3. All of these sites within the clover leaf structure of the tRNA sequence are occupied by a methylated nucleoside in some tRNA species of known sequence. It is concluded that methylation of tRNA from micro-organisms by enzymes from mammalian tissues in vitro probably does accurately represent the specificity of these enzymes in vivo. However, there was no evidence that the tumour extracts, which had considerably greater tRNA methylase activity than the normal tissues, had methylases with altered specificity capable of methylating sites not methylated in the normal tissues.

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