scholarly journals Studies in vivo on the biosynthesis of collagen and elastin in ascorbic acid-deficient guinea pigs. Evidence for the formation and degradation of a partially hydroxylated collagen

1970 ◽  
Vol 119 (3) ◽  
pp. 575-585 ◽  
Author(s):  
M. J. Barnes ◽  
B. J. Constable ◽  
L. F. Morton ◽  
E. Kodicek
Keyword(s):  
Molecular Weight ◽  
Ascorbic Acid ◽  
Guinea Pigs ◽  
Specific Radioactivity ◽  
Rapid Decline ◽  
Time Intervals ◽  
Skin Collagen ◽  
Labelled Compound ◽  
Degree Of Degradation

1. After the administration of l-[G-3H]proline to guinea pigs deprived of ascorbic acid for increasing periods of time, the specific radioactivities of proline and hydroxyproline in skin collagen and aortic elastin were determined at various time-intervals after administration of the labelled compound with a view to studying the formation and degradation of collagen and elastin both deficient in hydroxyproline. 2. As judged from the incorporation of radioactivity into elastin proline, elastin synthesis was not decreased in the ascorbic acid-deficient animals. There was however, a rapid decline in the specific radioactivity of elastin hydroxyproline. The proline/hydroxyproline specific-radioactivity ratio was approx. 1.5:1 after 6 days and 20:1 after 12 days of ascorbic acid deprivation, in contrast with the ratio of 1:1 in controls. The results suggested that the effect of ascorbic acid deficiency on elastin biosynthesis could be regarded as simply an elimination of hydroxylation of elastin proline with the formation and retention of a polymer increasingly deficient in hydroxyproline. 3. Collagen proline and hydroxyproline specific radioactivities were derived from material that was soluble in hot trichloroacetic acid, non-diffusible and collagenase-degradable. In contrast with elastin, there was a rapid decline in the specific radioactivity of proline as well as hydroxyproline in collagen from the ascorbic acid-deficient animals. However, the proline/hydroxyproline specific-radioactivity ratio in all samples from scorbutic animals was consistently slightly above 1:1. The results suggest the appearance in place of collagen, but in rapidly diminishing amounts, of a partially hydroxylated collagen in which the degree of hydroxylation may be decreased only by approx. 10%. 4. Incorporation of radioactivity into the diffusible hydroxyproline in skin remained relatively high despite the rapid decline in the incorporation of radioactivity into collagen. This observation is interpreted as indicative of an increasing degree of degradation of partially hydroxylated collagen to diffusible peptides. An alternative explanation might be that partially hydroxylated peptides are released to an increasing extent from ribosomes before they attain a length at least sufficient to render them non-diffusible. In either case it implies the accumulation in scurvy of low-molecular-weight peptides enriched in proline and deficient in hydroxyproline and could explain the failure to accumulate a high-molecular-weight collagen deficient in hydroxyproline. 5. It is thought, however, that, in addition, an inhibition of ribosomal amino acid incorporation leading to decreased synthesis of partially hydroxylated collagen may also occur, perhaps secondarily to impaired hydroxylation.

scholarly journals Studies in vivo on the biosynthesis of collagen and elastin in ascorbic acid-deficient guinea pigs

1969 ◽  
Vol 113 (2) ◽  
pp. 387-397 ◽  
Author(s):  
M. J. Barnes ◽  
B. J. Constable ◽  
E. Kodicek
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Specific Radioactivity ◽  
Cross Link ◽  
Control Groups ◽  
Acid Deficiency ◽  
Severe Impairment ◽  
Proline Incorporation

1. After the administration of labelled proline to guinea pigs deprived of ascorbic acid for 15 days, the dorsal skin was examined 5 days later in an attempt to detect the presence of hydroxyproline-deficient collagen (protocollagen). The extent of incorporation of proline into skin collagens indicated a severe impairment of collagen synthesis. 2. A comparison of proline and hydroxyproline specific radioactivities in diffusible peptides obtained by treatment with collagenase of either purified skin collagens or direct hot-trichloroacetic acid extracts of skin failed to indicate the presence of protocollagen. Possible reasons for this are discussed. 3. The incorporation results did not indicate an inability of normal collagen, i.e. collagen hydroxylated to the normal degree, to cross-link in scurvy. 4. Incorporation of labelled proline into aortic elastin isolated from the same animals did not indicate a decrease in elastin biosynthesis in ascorbic acid deficiency, beyond that attributable to the inanition accompanying the vitamin deficiency. The proline/hydroxyproline specific-radioactivity ratio in elastin from scorbutic guinea pigs was about 6:1 in contrast with the 1:1 ratio in control groups. It is concluded that the formation of elastin hydroxyproline was ascorbate-dependent and that a hydroxyproline-deficient elastin is formed and retained in scurvy. The formation of desmosines was unimpaired in scorbutic animals. 5. Studies with chick embryos confirmed the formation of elastin hydroxyproline from free proline. Incorporation of free hydroxyproline into elastin hydroxyproline was negligible. 6. Digestion of solubilized samples with collagenase indicated that the hydroxyproline in guinea-pig aortic elastin preparations was not derived from contamination by collagen. It is suggested that most if not all of the hydroxyproline in the guinea pig elastin preparations investigated can be considered an integral part of the elastin molecule.

Evidence for the in vivo formation of ascorbic acid 2-O-α-glucoside in guinea pigs and rats

1991 ◽  
Vol 42 (3) ◽  
pp. 625-631 ◽  
Author(s):  
Muto Norio ◽  
Yasuko Ban ◽  
Akiba Masanori ◽  
Yamamoto Itaru
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pigs

scholarly journals In Vivo Cultivation of Leukocytes in Diffusion Chambers: Requirement of Ascorbic Acid for Differentiation of Mononuclear Leukocytes to Fibroblasts

Blood ◽  
1961 ◽  
Vol 18 (3) ◽  
pp. 310-316 ◽  
Author(s):  
NICHOLAS L. PETRAKIS
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pigs ◽  
Mononuclear Leukocytes ◽  
Diffusion Chambers ◽  
Nuclear Enlargement

Abstract Studies were made to evaluate the influence of ascorbic acid upon the differentiation of mononuclear leukocytes to fibroblasts when cultivated in diffusion chambers, in vivo. Ascorbic acid-depleted leukocytes grown in ascorbic acid-deficient host guinea pigs developed into abnormal cellular forms characterized by nuclear enlargement, multipolar mitoses, and giant forms These changes could be reversed by treatment of the host guinea pigs with ascorbic acid. The findings indicate a direct cellular role of ascorbic acid in the differentiation of mononuclear leukocytes to fibroblasts.

Measurements of the rate of production of bacteria in the rumen of buffalo calves

1974 ◽  
Vol 83 (1) ◽  
pp. 13-17 ◽  
Author(s):  
U. B. Singh ◽  
D. N. Verma ◽  
A. Varma ◽  
S. K. Ranjhan
Keyword(s):  
Specific Radioactivity ◽  
Turnover Time ◽  
Sodium Sulphate ◽  
Bacterial Cells ◽  
Buffalo Calves ◽  
Time Intervals ◽  
Turn Over ◽  
Specific Radio

SUMMARYA technique is described for thein vivoestimation of the rate of production of bacteria in the rumen of buffalo calves. The animals were given their daily ration in 12 equal amounts at 2-h intervals. The bacterial cells from the rumen were labelled either with14C or36S byin vitroincubation in the presence of [U-14C]DL-leucine or35S-sodium sulphate. Labelled bacterial cells were injected in a single dose into the rumen. Samples of the ruminal fluid were drawn at various time intervals for 9 h and the specific radio-activity of the bacteria determined. The dilution in the specific radioactivity was used to calculate the turn-over time and rates of production of bacteria in the rumen. The average turnover time was 308 min. The production rate of bacteria averaged 211 mg/min (20·3 g/mole VFA produced).

THE UPTAKE AND DISTRIBUTION OF 14C-CLOMIPHENE CITRATE IN DIFFERENT ORGANS OF NEWBORN FEMALE GUINEA PIGS

1971 ◽  
Vol 68 (3) ◽  
pp. 605-613 ◽  
Author(s):  
K.-D. Schulz ◽  
F. Hölzel ◽  
G. Bettendorf
Keyword(s):  
Cerebral Cortex ◽  
Adrenal Gland ◽  
Guinea Pigs ◽  
Microsomal Fraction ◽  
Clomiphene Citrate ◽  
Time Intervals ◽  
Hypothalamic Region ◽  
Single Subcutaneous Injection ◽  
High Affinity ◽  
Labelled Compound

ABSTRACT Newborn female guinea pigs received a single subcutaneous injection of 150 μg 14C-clomiphene/l00 g body weight. At different time intervals after clomiphene administration the radioactivity was measured in the cerebral cortex, hypothalamic region, pituitary, ovary, liver, adrenal gland and uterus. As early as 1 hour after injection 14C-activity was detectable in all the organs examined. Corresponding to the well-known anti-oestrogenic and oestrogen-like activities of clomiphene, the oestrogenresponsive tissues of the hypothalamic region, pituitary and uterus indicated a high affinity for this compound. Compared with the cerebral cortex, these organs showed a 2- to 7-fold incorporation of 14C-radioactivity 3 hours after the injection. In the uterus a rather constant 14Clevel was maintained during a period of 25 hours. A high uptake and retention of the labelled compound were also detectable in the liver and the adrenal gland. The ovary has the capacity to accumulate a large amount of the 14C-labelled substance. But this ability is only demonstrable during the first 6 hours after clomiphene administration; after this the 14C-activity decreases rapidly, like the 14C-level in the blood plasma. The relevance of this result for the direct effect of clomiphene on ovarian stereoidogenesis is discussed. Furthermore the distribution of l4C-clomiphene was studied in the nuclear, mitochondrial and microsomal fraction and in the particle free supernatant of the above mentioned organs.

Glycosylation of plasma proteins with [U-14C]gIucose in vivo

1982 ◽  
Vol 60 (10) ◽  
pp. 942-951
Author(s):  
Rudolf Vrba ◽  
Stephen P. Adams
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
Sialic Acid ◽  
Plasma Proteins ◽  
Gel Filtration ◽  
Specific Radioactivity ◽  
Apparent Molecular Weight ◽  
Covalent Bonds ◽  
High Specific Radioactivity

Within 1–12 h after subcutaneous injection of [U-14C]glucose, significant amounts of 14C attached by stable (probably covalent) bonds were found in plasma proteins of rats. More than 30% of 14C of [U-14C]glucose injected per 1 g body weight was incorporated into proteins contained in 1 mL of plasma. Less than 5% of 14C of the [14C]glucose-labelled plasma proteins was soluble in cold dilute perchloric acid, whereas more than 80% of 14C in the [14C]glucose-labelled plasma proteins was soluble in 50% saturated solutions of ammonium sulfate. From [U-14C]glucose-labelled plasma proteins, approximately 50% of the incorporated 14C was recovered in carbohydrate moieties (sialic acid, 8–12%; mannose and galactose, 15–31%; hexosamines, 8–14%) and the rest of the 14C (42–64%) was recovered from protein residue. Gel-filtration and electrophoresis profiles of distribution of 14C in [U-14C]leucine-labelled plasma proteins were very similar to those of [U-14C]glucose-labelled plasma proteins; a relatively high specific radioactivity was observed in fractions having an apparent molecular weight of 105 × 103 or its multiples (220 × 103 and 520 × 103). However, about 99% of the incorporated 14C was recovered from the protein residue of [14C]leucine-labelled plasma proteins, whereas only traces of 14C were found in the carbohydrate moieties. [U-14C]Alanine is also a relatively poor precursor of 14C for incorporation into carbohydrate moieties of plasma proteins as compared with [U-14C]glucose.

scholarly journals The effect of scurvy on glycosaminoglycans of granulation tissue and costal cartilage

1968 ◽  
Vol 110 (4) ◽  
pp. 609-616 ◽  
Author(s):  
I. Antonowicz ◽  
E. Kodicek
Keyword(s):  
Ascorbic Acid ◽  
Granulation Tissue ◽  
Guinea Pigs ◽  
Costal Cartilage ◽  
Absolute Amount ◽  
Ascorbic Acid Deficiency ◽  
Acid Deficiency ◽  
And Cartilage

1. The effect of ascorbic acid deficiency on glycosaminoglycans of granulation tissue and cartilage of guinea pigs was investigated by determination of the changes in the glucosamine and galactosamine contents 12 days after tendonectomy. 2. In normal granulation tissue, the glucosamine and galactosamine contents rose to a peak at 5 and 10 days respectively, whereas the hydroxyproline and proline contents continued to rise throughout the 20 days after tendonectomy. 3. The galactosamine in scorbutic granulation tissue, but not in that of pair-fed controls, decreased significantly in absolute amount and relatively to glucosamine, which remained practically unchanged; the cartilage galactosamine did not decrease during the 22 days of deficiency owing to the presence of excess of preformed galactosaminoglycans, which masked the small amount of newly formed glycosaminoglycans. 4. The chemical results were confirmed by radioactivity studies in vivo of incorporation of [U−14C]glucose into galactosamine and glucosamine of scorbutic granulation tissue and cartilage. The incorporation of 14C into galactosamine decreased significantly in scurvy in both tissues. 5. The results indicated in both tissues a decreased formation of galactosamine during scurvy, although an increased degradation of polymerized glycosaminoglycans could not be entirely ruled out. It is concluded that, if lack of ascorbic acid causes an impaired galactosamine formation, the most likely position for the block may be in the UDP-N-acetylglucosamine 4-epimerase reaction.

Ketone body metabolism in ascorbic acid deficiency: in vivo utilization of ketone bodies in guinea pigs

1959 ◽  
Vol 196 (3) ◽  
pp. 607-610 ◽  
Author(s):  
Habeeb Bacchus ◽  
Albert F. Debons ◽  
Sidney Levin ◽  
John W. Wallace
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pigs ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Deficient Animal ◽  
Ascorbic Acid Deficiency ◽  
Acid Deficiency ◽  
Urinary Levels ◽  
Ketone Body Metabolism

Blood and urinary levels of ketone bodies were studied in normal, ascorbic acid-deficient, and pair-fed control, guinea pigs. The resting levels of ketone bodies in the blood and urine throughout the course of ascorbic acid-deficiency do not differ significantly from those of control animals. The ketonemic response to fasting is greater in the control animals than in the ascorbic acid-deficient animals. The disappearance of injected ketone bodies (ß-hydroxybutyrate) is decreased in the ascorbic acid-deficient animal. The data suggest that in ascorbic acid-deficiency there is a decreased utilization of ketone bodies coupled with a decreased spontaneous ketogenesis.

scholarly journals Iron loading and large doses of intravenous ascorbic acid promote lipid peroxidation in whole serum in guinea pigs

2001 ◽  
Vol 85 (6) ◽  
pp. 681-687 ◽  
Author(s):  
Maria Kapsokefalou ◽  
Dennis D Miller
Keyword(s):  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Guinea Pigs ◽  
Intraperitoneal Injection ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Iron Dextran ◽  
Cardiac Puncture

Large doses of ascorbic acid may mobilise Fe from Fe-binding proteins in vivo which in turn could catalyse lipid peroxidation, a process associated with degenerative diseases. This hypothesis was tested in vitro in the serum of Fe-loaded animals. Eighteen male guinea pigs weighing about 500 g on arrival were allocated to two groups of nine. Fe loading was induced in one group by two intraperitoneal injections of 200 mg iron dextran given on days 1 and 5. Blood (6 ml) was drawn from all animals on day 12 by cardiac puncture. Serum and LDL were separated. Serum was tested for loosely-bound Fe (bleomycin assay) and lipid peroxidation (thiobarbituric acid reactive substances (TBARS) assay) and LDL for susceptibility to in vitro oxidation (TBARS and conjugated diene assays). On day 12, another intraperitoneal injection of 200 mg iron dextran was given to the animals in the Fe-loaded group. On day 19, all animals were given 75 mg ascorbic acid by intraperitoneal injection. Blood (6 ml) was drawn 4 h later by cardiac puncture. Serum and LDL assays were repeated. Ascorbic acid increased loosely-bound Fe and in vitro oxidation in the serum from animals of the Fe-loaded group but not in the serum from animals of the control group. Susceptibility of LDL to in vitro oxidation increased after the ascorbic acid injection in the control group but there was no further increase in the Fe-loaded group. These data suggest that large doses of ascorbic acid promote Fe mobilisation and in vitro oxidation in the serum of Fe-loaded animals.

Measurements in vivo of the rate of production of protozoa in the rumen

1974 ◽  
Vol 41 (3) ◽  
pp. 299-303 ◽  
Author(s):  
U. B. Singh ◽  
A. Varma ◽  
D. N. Verma ◽  
S. K. Ranjhan
Keyword(s):  
Crude Protein ◽  
Research Council ◽  
Single Injection ◽  
Specific Radioactivity ◽  
National Research Council ◽  
Dilution Technique ◽  
Buffalo Calves ◽  
Time Intervals ◽  
Isotope Dilution Technique

SummaryThe rates of production of protozoa in the rumen of buffalo calves have been estimated using a single-injection isotope dilution technique. The calves were fed at 2 levels of crude protein, namely, 13% lower and 19% higher than that recommended by the National Research Council. The animals were given their rations at 2-h intervals for 3 weeks. Thereafter 14C-labelled rumen protozoa were injected into the rumen of each calf in a single injection. Samples of the rumen liquor were drawn at various time-intervals for 10 h and were analysed for the concentration of protozoa and radioactivity. The decline in the specific radioactivity of protozoa cells in the rumen as a function of time was used for calculating half life (t½). A mathematical equation was used to calculate the rate of production of protozoa. The average t½ was 1077 min for both groups and the rates of production of protozoa were 73·9 and 92·1mg/min in groups fed on low and high planes of crude protein respectively, showing that the production of protozoa is significantly (P < 0·01) higher in animals consuming a ration high in crude protein.

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