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PubMed1967

Inhibition of cell elongation in Avena coleoptile by hydroxyproline.

A study has been made of the hydroxyproline-induced inhibition of elongation of Avena coleoptile tissues. The isomers of 4-hydroxyproline differ in their effectiveness; only the L isomers are growth inhibitors with the cis form (allohydroxyproline) being more effective than the trans form (hydroxyproline). Hydroxyproline differs from other amino acid antagonists and protein synthesis inhibitors in respect to 2 characteristics of the growth inhibition. First, a certain increment of auxin-induced elongation must take place following addition of hydroxyproline before the growth is inhibited. In contrast, pretreatment with other amino acid antagonists or protein synthesis inhibitors completely eliminates the ability of Avena coleoptile sections to respond to auxin. Secondly, sucrose markedly increases the magnitude of the hydroxyproline inhibition; i.e., sucrose acts to inhibit rather than promote growth when in the presence of hydroxyproline. It appears that hydroxyproline is a specific inhibitor for the synthesis of some factor which is utilized in elongation. Following addition of hydroxyproline, auxin-induced elongation continues until the pool of this factor is exhausted; then elongation is inhibited.

Edible Grain↗

PubMed1982

Dialysable and non-dialysable hydroxyproline in the rat's urine: age related and diurnal variations.

1. Urinary dialysable and non-dialysable hydroxyproline, which are considered good indices of bone resorption and neoformation respectively, were determined in rats under conditions that modify skeleton metabolism, such as body growth and parathyroid or calcitonin administration. It was also investigated whether dialysable and non-dialysable hydroxyproline excretions showed significant circadian fluctuations in rats of different ages.2. Dialysable hydroxyproline excretion sharply decreased from the first to the fifth months of age and underwent further gradual reduction up to the fourteenth month of life. Non-dialysable hydroxyproline excretion followed a smoother decrease up to the fifth month, then remained constant. Urinary excretion of non-dialysable hydroxyproline expressed as a percentage of the total hydroxyprolinuria (n.d.%) slowly increased with advancing rat age.3. In 2-, 4- and 6-month old rats, dialysable hydroxyproline excretion showed significant circadian fluctuations with minima and maxima at the end of the dark and light fraction of the cycle respectively. Daily fluctuations were greater in young and adult rats (50-65% of the respective average levels) than in 4-month old rats (25%). Non-dialysable hydroxyproline excretion followed similar but less pronounced patterns. Significant circadian fluctuations of n.d.% were detectable only in 2- and 4-month old rats, with peaks at 04.00-05.00 hr, thus indicating that the bone formation/resorption ratio increased in the nocturnal fraction of the cycle.4. Young rats administered with calcitonin exhibited reduced levels of urinary dialysable but not of non-dialysable hydroxyproline when the hormone was given at 13.30 hr. No changes were observed when calcitonin was injected at 19.30 hr. On the contrary, both diurnal and nocturnal parathyroid hormone administration to young rats caused increased levels of dialysable and non-dialysable hydroxyproline of the same magnitude.

Age Factors↗

PubMed1981

Urinary excretion of glycosaminoglycans and hydroxyproline in Paget's disease of bone, compared with neoplastic invasion of bone.

Urinary glycosaminoglycan and hydroxyproline excretion was studied in 11 patients with clear evidence of Paget's disease of bone. Urinary hydroxyproline, cetyl pyridinium chloride (CPC)-precipitable uronic acid and CPC-precipitable hexosamine were expressed as ratios to urinary creatinine. Urine samples were concentrated x 1000 by vacuum dialysis and the glycosaminoglycans examined by electrophoresis on cellulose acetate followed by staining with alcian blue. All the cases studied showed markedly raised hydroxyproline excretion, whereas the uronic acid excretion was normal or only slightly raised in 10 of the 11 cases studied. One patient who had a raised uronic acid and raised hydroxyproline concentration was shown to have osteosarcoma as a complication of Paget's disease. THE VERY HIGH HYDROXYPROLINE: creatinine ratio in all cases of Paget's disease (mean 241.8 mmol hydroxyproline/mol creatinine) contrasted sharply with the cases of disseminated neoplasm, where the ratio was either normal or slightly raised (mean 29.3 mmol hydroxyproline/mol creatinine). The ratio of hydroxyproline to CPC-precipitable uronic acid was also markedly raised in cases of Paget's disease (mean 77.3 mmol hydroxyproline/mmol uronic acid) and was lower in the neoplastic group (mean 14.1 mmol hydroxyproline/mmol uronic acid) but showed no advantage over the hydroxyproline: creatinine ratio in differentiating the two groups. THE URINARY HYDROXYPROLINE: creatinine ratio promises to be of value in differentiating between Paget's disease of bone and neoplastic invasion of bone. A marked rise in CPC-precipitable uronic acid excretion alone is more suggestive of neoplastic invasion of bone, and if associated with a marked increase in hydroxyproline excretion, it raises the possibility of neoplastic change in Paget's disease of bone. The results of this study also suggest that bone collagen, rather than bone tissue in general, is primarily affected in Paget's disease.

Aged↗

PubMed1984

Urinary hydroxyproline and prognosis in human breast cancer.

The excretion of urinary hydroxyproline has been measured before mastectomy in 342 patients presenting with breast cancer for the first time to Guy's Hospital. The first 106 women were maintained on a gelatine-free diet whilst the remainder were on unrestricted diet. In both dietary groups hydroxyproline levels or the ratio of hydroxyproline to urinary creatinine were not related to pathological stage or histological grade. The time between initial presentation and subsequent bone metastases was negatively and significantly associated with hydroxyproline excretion (P less than 0.05) and the ratio of hydroxyproline to creatinine (P less than 0.01) in women on a gelatine-free diet. A similar, but not significant, trend was observed in patients on unrestricted diet. Although hydroxyproline excretion was related to the time to onset of bone metastases the amount of hydroxyproline excreted by these patients was not significantly different from patients who had recurrences at sites other than bone or patients who were disease-free up to 5 years after initial diagnosis. The conclusion is that hydroxyproline is of little value in the early detection of bone metastases.

Adult↗

PubMed1977

Total hydroxyproline in urine of 4 to 6 year-old children--an investigation on its relationship to growth and nutrition.

We analysed over a period of 30-32 days the daily total hydroxyproline and creatinine excretine in urine from 9 healthy, normally fed 4 to 6 year-old children (2 girls, 7 boys). The average urinary hydroxyproline excretion was 45.6 mg/24 hr, with a coefficient of variation of 25.6%. Urinary hydroxyproline for individual children showed distinct differences from day to day, which were independent of urine volume. There were significant differences between the mean values for urine hydroxyproline in individual children, which were independent of age. The average creatinine in urine was 346/24 hr with a coefficient of variation of 17.7%. The hydroxyproline-index did not define the nutritional state of these normally developed children on a normal diet. Dietary hydroxyproline contributed 7.4% to the total urinary hydroxyproline in our investigation. There was a close correlation between urine hydroxyproline excretion and growth velocity in each child.

Child↗

PubMed1979

The clinical measurement of urinary total hydroxyproline excretion.

The effect of dietary control on the day-to-day variation in total hydroxyproline excretion has been examined in two studies. In the first, a normal volunteer ate a controlled diet containing varying gelatin supplements for several weeks. In the second, the effect of removing hydroxyproline-containing foods from the diets of 8 volunteers was examined. Both studies confirm that the day-to-day variation in total hydroxyproline excretion falls when the gelatin content of the diet is decreased, whether the results are expressed as total hydroxyproline excretion rate or as the total hydroxyproline: creatinine ratio. This fall in variation takes place within 24 h of dietary control beginning and therefore longer periods of dietary restrictions to achieve optimum precision in the measurement of total hydroxyproline are unnecessary. For some analytical methods, results are better expressed as the ratio total hydroxyproline:creatinine than as the total hydroxyproline excretion rate.

Adult↗

PubMed1980

Effects of aging on hydroxyproline in human heart muscle.

Hydroxyproline concentration in the NaCl-soluble, TCA-soluble, and residual fractions of heart muscle was chemically determined in 40 autopsy subjects (25 men and 15 women), to study the effects of aging. In the left ventricle, the total hydroxyproline content of the endocardium and papillary muscle increased significantly in relation to age; the increase was greatest in the TCA-soluble fraction, followed by the residual fraction. Statistical analysis revealed that hydroxyproline in the residual fraction increased from the epicardium to the endocardium and then to the papillary muscle. Significant negative correlations were found between heart weight and total hydroxyproline in the epicardium and endocardium. In the right ventricle, a significant negative correlation was noted between heart weight and total hydroxyproline content. Though no correlations were evident between age and hydroxyproline content in females, significant correlations were observed between age and the total hydroxyproline content of the endocardium and papillary muscle in males. Furthermore, soluble collagen increased in most parts of the heart in females, but insoluble collagen increased in all parts of the heart in males. It is concluded that the hydroxyproline content of heart muscle increases in proportion to age and is in inverse proportion to heart weight. The increase occurs in the TCA-soluble and residual fractions, and extends from the endocardium to the papillary muscle. More profound changes in collagen metabolism are observed in males.

Adult↗

PubMed1979

Hydroxyproline metabolism in type II hyperprolinaemia.

Hydroxyproline metabolism was studied in two patients with type II hyperprolinaemia (HP II) using oral loadings of hydroxyproline or hydroxyproline-ornithine. delta 1-pyrroline-3-hydroxy-5-carboxylic acid (3 OH-PC) and delta 1-pyrroline-5-carboxylic acid (PC) were identified in the urine. The urinary excretion of both 3-OH-PC and PC increased in HP II patients but not in healthy controls during oral loading of hydroxyproline and hydroxyproline-ornithine. The plasma level of proline in patients with HP II is very high but the hydroxyproline concentration is normal or only slightly increased. Therefore one can assume that hydroxyproline is converted to pyrrole-2-carboxylic acid, which is excreted in urine as a glycine conjugate. In this study it was demonstrated that the highly elevated plasma level of proline in one of the patients with HP II decreased greatly after hydroxyproline-ornithine load; this change was followed by a 40-fold rise in urinary excretion of proline.

Adolescent↗

PubMed1977

Effect of mithramycin on hydroxyproline metabolism in Paget's disease.

Hydroxyproline was measured in the plasma and urine of six patients with symptomatic osseous Paget's disease before and after parenteral mithramycin treatment. The plasma profile data included free, peptide, and protein hydroxyproline values. Corresponding urine samples were analyzed for total hydroxyproline content and, in some instances, for free hydroxyproline. Plasma values of free and peptide hydroxyproline fell promptly toward the range of normal within 24 hr after the first intravenous injection of mithramycin. Protein hydroxyproline in the plasma was slightly but significantly lower than in the 15 normal control subjects, and this value did not change appreciably over the 4-day period during which the patients were treated. The urine excretion rate of total hydroxyproline decreased precipitously. Our results support the hypothesis that mithramycin rapidly reduces the accelerated rate of "collagenolytic" activity of osteocytes and osteoclasts in this disorder, presumably by an inhibiting effect on these bone-modeling cells. The major degradative lesion, as reflected in the plasma and urine, is characterized by the production of non-TCA-precipitable peptides containing hydroxyproline, which rapidly fell to normal levels after the administration of mithramycin.

Humans↗

PubMedDate not supplied

Semiquantitative evaluation of hepatic fibrosis by measuring tissue hydroxyproline.

BACKGROUND/AIMS: It is important to evaluate the degree of hepatic fibrosis when diagnosing and treating hepatic cirrhosis. We focused on hydroxyproline, which is detected specifically in collagen, which plays a major role in hepatic fibrosis. The correlations between liver tissue hydroxyproline residue levels and the degree of hepatic fibrosis were examined in dogs with dimethylnitrosamine-induced fibrotic livers. METHODOLOGY: Dimethylnitrosamine was administered to dogs to establish experimental hepatic fibrosis. Paraffinized sections of liver specimens, stained with hematoxylin-eosin and azan, were examined and the degree of hepatic fibrosis was graded. About three-milligram samples of liver tissue were loaded onto a fully automated liquid chromatograph and the levels of hydroxyproline residues were measured. RESULTS: The liver tissue hydroxyproline appeared to reflect the degree of hepatic fibrosis. The liver tissue hydroxyproline levels and pathological hepatic fibrosis grades correlated significantly (p<0.05). CONCLUSIONS: Tissue hydroxyproline appears to be a more useful fibrosis marker, because hydroxyproline is influenced less by other factors. Furthermore, our results demonstrate that a very small amount of liver tissue (wet weight 3 mg) was enough to enable the levels of hydroxyproline residues to be measured by an automated amino acid analyzer (JLC-3000) and hepatic fibrosis is expressed as the numerical value by this analysis.

Animals↗

PubMed1991

Synthesis and characterization of magnetically responsive albumin microspheres containing cis-hydroxyproline for scar inhibition.

Magnetically responsive albumin microspheres containing the proline analog, cis-hydroxyproline, were synthesized and their in-vitro physical properties were characterized. These microspheres have an average size of 1.1 +/- 0.3 microns with 94% of the microspheres less than 2.0 microns. They are uniformly spherical and contain 67% albumin, 22% magnetite, and 8% cis-hydroxyproline. The cis-hydroxyproline is releasable during a 72-h period and demonstrates a slow, releasable pool that constitutes approximately 50% of the incorporated drug. cis-Hydroxyproline is neither chemically nor biologically altered during its incorporation into the microsphere. cis-Hydroxyproline release from microspheres results in the in vitro inhibition of collagen secretion, which is indistinguishable from unincorporated cis-hydroxyproline. In a rat-tail animal model these microspheres were selectively targeted using an external magnetic field applied to a 1.5-2.0-cm target site. Fifty to 80% of the infused microspheres were localized to this site, whereas without a magnetic field only 15-20% of the microspheres are localized to this site. cis-Hydroxyproline microspheres resulted in a 16% decrease in collagen content in a scar model when compared with untreated animals (p less than 0.05). With further refinement of this method of drug delivery, clinically useful inhibition of scar formation may result.

Animals↗

PubMed1977

Hydroxyproline fractions in serum and urine of rats during wound healing.

Total hydroxyproline in urine and free hydroxyproline, free and peptide hydroxyproline and protein bound hydroxyproline in serum are measured during wound healing in rats. The free and free+peptide fractions vary in concert with each other and with urine hydroxyproline. Protein bound hydroxyproline fractions take a very different course and behave as an acute phase reactant. The results suggest that protein bound hydroxyproline does not mirror collagen turnover but may be more relevant to C1q or complement metabolism.

Animals↗

PubMed1995

A simple and automated HPLC method for determination of total hydroxyproline in urine. Comparison with excretion of pyridinolines.

An HPLC method for measuring total hydroxyproline in human urine was validated. Hydroxyproline derivatization was achieved with 9-fluorenylmethyl chloroformate after blocking primary amino acids with orthophthaldialdehyde. The derivatives (hydroxyproline and internal standard) were separated by reversed phase high-performance liquid chromatography and detected by absorbance at 254 nm. Duplicate measurements of hydroxyproline have a coefficient of variation of 3.9% and the recovery in spiked urine samples is between 99.5 and 100.8%. We have compared the HPLC procedure with a commercial colorimetric assay. Analytical criteria of these methods are identical. Regression analysis, involving 50 samples, shows an excellent correlation between hydroxyproline chromatographic (y) and colorimetric (x) procedures: y = 0.989x + 2.99 (r = 0.976). Hydroxyproline excretion was determined in urine samples from 76 women more than 5 years post-menopause. The mean hydroxyproline/creatinine ratio in this group was 19.3 +/- 5.6 mumol/mmol (range 10.6-34.7). Finally, we compared in the same urinary samples hydroxyproline excretion with pyridinoline excretion (hydroxylysylpyridinoline and lysylpyridinoline), a new marker of bone resorption. The values show a significant correlation, with r = 0.417 for hydroxylysylpyridinoline and r = 0.443 for lysylpyridinoline.

Aged↗

PubMed1984

Hydroxyproline excretion in urine of smokers and passive smokers.

Urinary hydroxyproline excretion was investigated in 125 male cigarette smokers, 194 male pipe and/or cigar smokers, and 24 male nonsmokers. Hydroxyproline excretion was calculated either as hydroxyproline/creatinine ratio or as body surface-standardized amounts of hydroxyproline excreted in urine sampled during day, during night, or over 24 hr. The association of hydroxyproline excretion with smoke uptake variables such as daily cigarette consumption, carboxyhemoglobin, serum cotinine, and nicotine in urine and with self-reported passive smoking exposure in nonsmokers was analyzed. The hydroxyproline/creatinine ratio was found to be unsuitable as a measure of hydroxyproline excretion since creatinine urine concentrations correlate inversely with smoke uptake in cigarette and pipe/cigar smokers. The amount of hydroxyproline excreted in 24-hr urine and standardized for body surface was not significantly associated with smoke uptake in pipe/cigar smokers or exposure to passive smoking in nonsmokers. In cigarette smokers the situation appeared similar, although the results were less clear-cut. The data do not favor the premise that measuring urinary hydroxyproline excretion is an accurate method of investigating a lung-damaging effect of smoking, passive smoking, or air pollution.

Adult↗

PubMed1981

tuberous sclerosis: hydroxyproline content in urine and tissues.

To elucidate the nature of an overabundance of collagen seen on microscopic examination in tuberous sclerous (TS), the hydroxyproline content in tissues and urine was determined. TS tissues of 5 patients were obtained on necropsy or plastic surgery. Urine was collected from 10 patients with TS and 19 controls. Tumors in kidney, pancreas, lung and heart but not brain contained more hydroxyproline than the surrounding tissues. In brain with the lowest hydroxyproline content, the tumor showed reduced hydroxyproline compared to normal. Collagen sheet in TS skin and shagreen patch showed the same hydroxyproline content as control skin. Th urinary hydroxyproline: creatinine ratios of the patients with TS were all higher than those in age-matched controls with or without anticonvulsant treatment except for congenital muscular dystrophy. The higher content of hydroxyproline in several affected tissues and urine of patients with TS might indicate that an increase in collagen synthesis occurs in TS.

Adolescent↗

PubMed1990

Differentiation of hydroxyproline isomers and isobars in peptides by tandem mass spectrometry.

The isomeric 3- and 4-hydroxyprolines are isobaric with the isomers leucine and isoleucine, and all four have, therefore, the same "residue mass" of 113. Secondary fragmentation processes were found that differentiate the hydroxyproline isomers from each other and from the leucines. Variants of synthetic bradykinin containing one or two hydroxyproline moieties were prepared by using manual Edman degradation and/or enzymatic methods. The tandem mass spectra of these peptides were recorded. The C-terminal wn fragment ions allow the differentiation of 4-hydroxyproline from the 3-isomer and isoleucine, while the N-terminal an ions containing 4-hydroxyproline undergo H2O elimination to differentiate this amino acid from the 3-isomer and leucine. Lys-C digestion of a mussel adhesive protein produced a set of decapeptides varying in the degree of hydroxylation of proline and tyrosine. Heterogeneity with respect to 3-hydroxyproline and 4-hydroxyproline at a certain position in these peptides was assessed by tandem mass spectrometry based on the wn ion series in the CID spectra of these Lys-C peptides. Some N-terminal ions further allow for the differentiation of these two isomeric species.

Hydroxyproline↗

PubMed1995

Determination of free hydroxyproline and proline in human serum by high-performance liquid chromatography using 4-(5,6-dimethoxy-2-phthalimidinyl)phenylsulfonyl chloride as a pre-column fluorescent labelling reagent.

A fluorescent labelling reagent, 4-(5,6-dimethoxy-2-phthalimidinyl)phenylsulfonyl chloride, was designed for the determination of amines by precolumn HPLC and was applied to the simultaneous determination of hydroxyproline and proline in serum. The reagent reacted with hydroxyproline and proline at 30 degrees C for 10 min to produce the fluorescent derivatives, which were separated on a reversed-phase column by gradient elution with phosphate buffer (1 mmol l-1, pH 7) and acetonitrile and detected by fluorescence measurement at 315 nm (excitation) and 385 nm (emission). The detection limits (signal-to-noise ratio = 3) for both hydroxyproline and proline were 10 fmol per injection. The within-day (n = 10) and day-to-day (n = 5) relative standard deviations using human sera were less than 2.16% and 2.75%, respectively, for hydroxyproline and less than 2.30% and 3.25%, respectively, for proline. The concentrations of free hydroxyproline and proline in normal human sera (n = 13) were 5.6-18.0 and 137.6-252.6 mumol l-1, respectively. The proposed method was also applied to the determination of hydroxyproline and proline in sera from patients with chronic renal failure. The mean concentrations of hydroxyproline and proline in chronic renal failure were about 2.6 and 1.6 times higher, respectively, than those in normal human sera.

Chromatography, High Pressure Liquid↗

PubMed1981

Urinary total hydroxyproline excretion in patients with Turner's syndrome and Klinefelter's syndrome.

Urinary total hydroxyproline excretion in patients with Turner's syndrome and Klinefelter's syndrome was studied. Among the patients with Turner's syndrome hydroxyproline excretion was relatively low in girls 11-14 years old and somewhat increased in 14-17 age groups. Above 17 years of age urinary total hydroxyproline excretion was significantly higher than in the control. In patients with Klinefelter's syndrome at the age below 11 and above 17 years normal hydroxyproline values were observed. In 3 sixteen-year-old boys with 47, XXY karyotype, excretion of hydroxyproline with urine was significantly lower than in the control. Relatively low values of total hydroxyproline in urine of 11-14 year-old girls with Turner's syndrome and decreased in boys with Klinefelter's syndrome result, most probably, from the absence of hormonal changes typical for the puberty. However, concentration of hydroxyproline in urine does not correlate with serum FSH and LH levels. It is not affected by the enhancement of changes in the bone system either. The presented data encourage further studies on the connective tissue biochemistry in the patients with numerical aberrations sex chromosomes.

Adolescent↗