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PubMed1989

Bone alkaline phosphatase isoenzyme and urinary hydroxyproline in healthy subjects, patients with osteolytic metastases, and patients with primary hyperparathyroidism.

The values of urinary hydroxyproline excretion reflecting the bone remodelling by osteoclasts, and the bone isoenzyme of serum alkaline phosphatase reflecting the osteoblastic function, in 100 randomly selected healthy subjects, 100 patients with primary hyperparathyroidism, and 100 patients with osteolytic secondary tumorous deposits in the skeleton showed a bivariate lognormal distribution. Hotelling's test revealed highly significant differences in the biochemical values among these three conditions, even when Bonferroni's modification of the test was used. The individual biochemical values, however, displayed many mutual overlaps. Despite this, the discriminatory analysis based on bivariate biochemical data resulted in a correct diagnosis in all healthy subjects, in 82 patients with primary hyperparathyroidism, and in 93 patients with osteolytic metastases. The simultaneous determinations of urinary hydroxyproline excretion and the bone alkaline phosphatase insoenzyme improve the differential diagnosis between these conditions. The predominance of urinary hydroxyproline excretion relative to bone alkaline phosphatase isoenzyme suggests an osteolytic metastasis. Proportionately elevated both hydroxyproline and bone alkaline phosphatase isoenzyme indicate the presence of primary hyperparathyroidism. This shows the importance of a correct biometrical processing of data. Nevertheless, a complex clinical evaluation is always mandatory.

Adult↗
PubMed1987

A method for serum C1q based on its hydroxyproline content.

The radial immunodiffusion assay overestimates the C1q in serum. Here we describe a convenient, accurate procedure for measuring C1q in 250 microL of dialyzed serum. This method is based on our previous findings that all C1q in serum precipitates with the euglobulin fraction and that all other serum proteins containing hydroxyproline are excluded from this fraction. Because C1q is 4.3% hydroxyproline, the concentration of C1q in serum can therefore be calculated from the hydroxyproline content of the euglobulin fraction. The procedure, all done in the same tube, consists of precipitating the euglobulin fraction, digesting it with HClO4, and converting hydroxyproline to the corresponding pyrrole, which is extracted with toluene and measured by absorbance at 560 nm.

Arthritis, Rheumatoid↗
PubMed1988

Liquid-chromatographic determination of total hydroxyproline in urine.

In this method for quantifying 4-hydroxyproline in human urine, 50 microL of urine is hydrolyzed, derivatized with phenylisothiocyanate (PITC), and then quantified by reversed-phase HPLC with ultraviolet detection. The detection limit in urine is 373 pg of hydroxyproline per 50-microL injection. The total CVs for high- and low-concentration pools are 5.3% and 3.9%, respectively (10 runs in 10 days). The standard curve of the assay is linear over a range of 0 to 22 nmol per injection. We estimated the normal range for hydroxyproline excretion in men on an unrestricted diet to be 123-308 mumol/24 h. We also report hydroxyproline concentrations in patients with metastatic bone disease and cirrhosis of the liver.

Chromatography, Liquid↗
PubMedDate not supplied

[Urinary excretion of hydroxyproline by patients with multiple sclerosis].

Total urinary hydroxyproline was determined 79 times by the Prockop-Udenfried method in 61 patients with multiple sclerosis. All patients had the pyramidal syndrome. Depending on the intensity of paresis at the time of the study the patients were divided into two groups: Group I--patients with slight paresis. Group II--patients with major paresis or paralysis. The control group comprised 45 healthy subjects. The mean urinary hydroxyproline excretion was in both groups as a whole and in each group separately not different significantly from that in the control group. The values of hydroxyproline excretion depended on the duration of paresis, and were highest in both groups 2 weeks to 1 year after the onset of paresis, and then they decreased in two successive time periods: 1-5 and 5-17 years of the disease. The values of hydroxyproline excretion were significantly above the control level only in patients with severe paresis or paralysis of up to 1 year duration, and might have been due to increased catabolism of collagen in the bones of the paralysed extremities in the period of the so called acute osteoporosis.

Adult↗
PubMed1977

Hydroxyproline excretion following renal transplantation: comparison with values found in primary hyperparathyroidism.

The amounts of total hydroxyproline (THP), free hydroxyproline (FHP) and non-dialysable hydroxyproline (NDHP) excreted in the urine by six patients with chronic renal failure who received kidney transplants and six patients with primary hyperparathyroidism were studied. Following transplantation three of the four patients with radiological evidence of hyperparathyroidism developed hypercalcaemia and excreted more than 360 mumol THP/24 hours on at least one occasion. The remaining patients were normocalcaemic and excreted less THP and a higher proportion of NDHP. In all patients with primary hyperparathyroidism, THP excretion fell after adenoma removal but there was an increased excretion of NDHP:THP. It is suggested that studies of hydroxyproline excretion may contribute to clinical assessment of healing of renal osteodystrophy and involution of the parathyroid glands after renal allograft transplantation.

Adult↗
PubMed1986

The low hydroxyproline content of prematurely ruptured human fetal membranes.

Since collagen is one of the main factors responsible for the mechanical properties of soft tissue, we have determined the hydroxyproline content of the placental amnion, the free amnion and the chorion of 32 unruptured and 25 prematurely ruptured human fetal membranes. The hydroxyproline content of prematurely ruptured membranes was approximately 50% lower than in unruptured membranes. Hydroxyproline (microgram/mg lyophilized tissue), reported as mean +/- SD, was: 19.46 +/- 3.60 vs 37.53 +/- 8.93 for placental amnion; 16.97 +/- 3.93 vs 33.00 +/- 8.25 for free amnion, and 7.74 +/- 3.00 vs 13.23 +/- 3.95 for the chorion. This finding and the known decrease of hydroxyproline content of the amnion towards the end of gestation in normally evolving pregnancies suggest that an abnormally low collagen content may be the general cause of prematurely ruptured human fetal membranes.

Amnion↗
PubMedDate not supplied

[Urinary excretion of hydroxyproline in funnel chest deformity].

Excretion of hydroxyproline with urine was studied in 16 children with localized form of funnel chest deformation simultaneously with Marfan and Ehlers-Danlos syndromes, in 9 children with the localized form of deformation within 6-8 months after thorax surgical plastic operation as well as in 3 children with Ehlers-Danlos syndrome but without funnel chest deformation. Funnel chest deformation of the II-III degree, independently of its form, was accompanied by a decrease of total hydroxyproline in urine as compared with healthy children of the similar age. The hydroxyproline excretion was normalized after thoracoplastic operation in the children with localized form of the chest deformation. In Ehlers-Danlos syndrome, independently on presence or absence of the chest deformation, relative content of free hydroxyproline was increased in urine, while the peptide-bound amino acid was decreased (peptides with molecular mass above 700 daltons); this phenomenon appears to be a characteristic property of the syndrome.

Adolescent↗
PubMed1986

Liquid-chromatographic determination of 4-hydroxyproline in urine.

In this method for 4-hydroxyproline in urine, hydroxyproline is derivatized with 4-chloro-7-nitrobenzofurazan, with subsequent estimation by reversed-phase "high-performance" liquid chromatography. The ranges for excretion of free and total hydroxyproline while the subjects were ingesting unrestricted diets were 2-29 and 122-374 mumol/24 h (n = 21), respectively, with no significant sex-related difference. A comparison with results by colorimetry indicated no significant differences: mean (n = 18) concentrations (mumol/L) of hydroxyproline in urine were 180 (SD 149) by the present method, 163 (SD 166) by colorimetry. For protein hydrolysate the respective values were 5.9 (SD 2.7) and 6.7 (SD 2.9).

Chromatography, High Pressure Liquid↗
PubMed1979

[Urinary excretion of hydroxyproline in patients with chronic respiratory insufficiency (author's transl)].

The level of urinary excretion of hydroxyproline is considered as an index of the metabolic activity of the collagen. It increases in situations which include an increase in the osteoblastic activity or in the bone resorption. In respiratory insufficiency a series of conditions occur which are theoretically capable of modyfing this parameter. Twelve patients (9 males and 3 women) with chronic respiratory disease in a situation of respiratory insufficiency (hypoxemia and/or hypercapnia at rest) were studied. The urinary excretion of hydroxyproline in these patients was 15.30 +/- 8.16 mg/day/m2, significantly greater than that of a control group with similar characteristics which was 9.97 +/- 3.07 mg/day/m2 (p less than 0.05; Student's t test). The existence of a significant correlation between the urinary excretion of hydroxyproline and the degree of hypoxemia (r = 0.66; p less than 0.01) was likewise verified; in the same way, although to a lesser degree with the hypercapnia (r = 0.62; p less than 0.05). The different factors capable of influencing the bone metabolism in respiratory insufficiency are discussed, as well as the effects of the medications used by these patients. It is possible, on the other hand, that the increase of the urinary excretion of hydroxyproline does not depend only on alterations in the metabolic condition of the bone, but also on a reduction in the hepatic metabolism of the amino acid in relation with gasometric modifications.

Aged↗
PubMed1978

Measurement of free and free-plus-peptide hydroxyproline fractions in plasma.

Plasma hydroxyproline fractions--free-plus-peptide and free--were determined by a method involving centrifugal ultrafiltration and the procedure of Kivirikko et al. [Anal. Biochem. 19, 249 (1967)]. Within- and between-day precision (CV) for the combined fractions was 4--5% and 2.8--6%, respectively. Mean analytical recoveries of free hydroxyproline were 95.2% (87--109%) in the normal range, and 97% (91--108%) in the above-normal range. Normal ranges for plasma hydroxyproline fractions, based on data for 11 men and 19 women, were free-plus-peptide, 7.5--25.3; free, 4.9--22.7; and peptide (calculated), 0.1--5.1 mumol of hydroxyproline per litre, respectively. These ranges showed no sex-related differences and were gaussian in distribution. A factor was derived to transform data on concentrations in ultrafiltrate into plasma concentrations.

Humans↗
PubMed1982

[Study of Urinary excretion of total, free, and non-dialysable conjugated hydroxyproline in paraplegics].

Eighteen paraplegics with or without neurogenic osteo-arthropathy (POAN) were evaluated for variations in their urinary excretion levels of total (T), and free (L) hydroxyproline and its non-dialysable (ND) and dialysable (D) peptide fractions. Increases in urinary hydroxyproline, moderate rises in free hydroxyproline and more substantial increases in dialysable and non-dialysable peptide fractions could be observed in these patients who all were affected with osteoporosis of disuse. Only variations in dialysable hydroxyproline could be used to differentiate between POAN + and POAN - patients. Of the various ratios which were analyzed (ND/T, L/ND, and D/ND), the D/ND ratio appears to be the most useful for diagnosis and monitoring of patients with POAN.

Adolescent↗
PubMed1981

[Urinary and serum hydroxyproline in the diagnosis of bone metastases of prostatic cancer].

Of 31 patients with prostatic cancer, 21 have skeletal metastases proven by bone scintigraphy and/or radiology. The sensitivity and specificity of the following measurements are compared: total urinary hydroxyproline, urinary hydroxyproline/creatinine ratio, free serum hydroxyproline, alkaline and prostatic phosphatases and serum calcium. The hydroxyproline/creatinine ratio is the most sensitive measurement for the diagnosis of bone metastasis, while total urinary hydroxyproline excretion per 24 hours is the most specific. Free serum hydroxyproline has no particular significance for this diagnosis. The alkaline and acid phosphatases are elevated but are not specific. Serum calcium decreases when skeletal metastases are present.

Acid Phosphatase↗
PubMed1981

[Comparative evaluation of hydroxyproline in urine and in serum as a possible clinical parameter for radiation-induced destruction of connective tissue due to fractionated radiation therapy (author's transl)].

In the course of postoperative fractionated radiation therapy hydroxyproline was evaluated as a biochemical parameter of radiation damage in 60 patients with different tumour diseases. At different times before, during and after therapy, hydroxyproline in serum was evaluated according to the method of Dabew and Struck, hydroxyproline in urine according to the test combination "hypronosticon" (Organon-Technika). There was no correlation to be found between hydroxyproline in serum or urine, clinical course of disease and radiation dose. Possible explanations were discussed.

Cobalt Radioisotopes↗
PubMed1994

[Effect of furosemide added to peritoneal dialysis fluid on hydroxyproline excretion in dialysate and urine].

The effect of furosemide (1500 mg/21 of peritoneal dialysis fluid) on excretion of hydroxyproline in dialysate and its renal clearance was investigated in 12 patients with end-stage renal disease on regular dialysis treatment. The 37 +/- 8% and 20 +/- 6% increase of D/S ratio of hydroxyproline after 5 and 8 hours of dwell, respectively, and 52 +/- 24% increase of renal clearance of hydroxyproline were induced by furosemide, which indicate its significant influence on peritoneal and renal removal of hydroxyproline.

Adult↗
PubMed1982

Comparative and developmental studies on 4-hydroxy-2-oxoglutarate aldolase and hydroxyproline oxidase.

1. In rats, liver 4-hydroxy-2-oxoglutarate aldolase and hydroxyproline oxidase activities are maximal in the suckling period. 2. Liver activities for 4-hydroxy-2-oxoglutarate aldolase, alanine-glyoxylate aminotransferase, serine-pyruvate aminotransferase and serine dehydratase, but not hydroxyproline oxidase, are increased in rats on a high-fat, carbohydrate-free diet. 3. It is suggested that 4-hydroxy-2-oxoglutarate may be a significant source of glyoxylate for glycine and hence glucose formation. 4. Mammalian liver hydroxyproline oxidase activity is higher in carnivorous species; necessary, perhaps, to metabolise a relatively large influx of hydroxyproline on a flesh diet.

Aging↗
PubMed2003

Hydroxylation-induced stabilization of the collagen triple helix. Further characterization of peptides with 4(R)-hydroxyproline in the Xaa position.

4(R)-Hydroxyproline in the Yaa position of the -Gly-Xaa-Yaa-repeated sequence of collagen plays a crucial role in the stability of the triple helix. Since the peptide (4(R)-Hyp-Pro-Gly)10 does not form a triple helix, it was generally believed that polypeptides with a -Gly-4(R)-Hyp-Yaa-repeated sequence do not form a triple helix. Recently, we found that acetyl-(Gly-4(R)-Hyp-Thr)10-NH2 forms a triple helix in aqueous solutions. To further study the role of 4(R)-hydroxyproline in the Xaa position, we made a series of acetyl-(Gly-4(R)-Hyp-Yaa)10-NH2 peptides where Yaa was alanine, serine, valine, and allo-threonine. We previously hypothesized that the hydroxyl group of threonine might form a hydrogen bond to the hydroxyl group of 4(R)hydroxyproline. In water, only the threonine- and the valine-containing peptides were triple helical. The remaining peptides did not form a triple helix in water. In 1,2- and in 1,3-propanediol at 4 degrees C, all the soluble peptides were triple helical. From the transition temperature of the triple helices, it was found that among the examined residues, threonine was the most stable residue in the acetyl-(Gly-4(R)-Hyp-Yaa)10-NH2 peptide. The transition temperatures of the valine- and allo-threonine-containing peptides were 10 degrees lower than those of the threonine peptide. Surprisingly, the serine-containing peptide was the least stable. These results indicate that the stability of these peptides depends on the presence of a methyl group as well as the hydroxyl group and that the stereo configuration of the two groups is essential for the stability. In the threonine peptide, we hypothesize that the methyl group shields the interchain hydrogen bond between the glycine and the Xaa residue from water and that the hydroxyl groups of threonine and 4(R)hydroxyproline can form direct or water-mediated hydrogen bonds.

Circular Dichroism↗
PubMed1966

Role of oxygen fixation in hydroxyproline biosynthesis by etiolated seedlings.

Etiolated maize and soybean seedlings were grown for several days in atmospheres enriched with O(18). Hydroxyproline subsequently isolated from the seedlings by column and thin-layer chromatography was labeled with excess O(18), but proline was not. Control experiments in which seedlings were grown in H(2)O(18) and unlabeled atmospheres demonstrated that neither proline nor hydroxyproline was labeled with excess O(18). It was concluded that oxygen fixation is an essential feature of hydroxyproline biosynthesis in these seedlings, and that the hydroxyl oxygen atom in hydroxyproline is derived from molecular oxygen and not from water; similar results have been reported previously for sycamore cell suspensions.

Journal Article↗
PubMed1967

Reversal of hydroxyproline-induced inhibition of elongation of Avena coleoptiles.

Hydroxy-l-proline-induced inhibition of elongation of Avena coleoptile segments was measured in water and in indole-3-acetic acid. This inhibition was completely reversed by l-proline.Time-sequence experiments revealed that some time had to elapse, or some elongation had to occur, prior to the onset of hydroxyproline inhibition. The presence of sucrose supported the rate of auxin-induced elongation throughout a 24-hour period, and enhanced the effectiveness of hydroxyproline as an inhibitor of elongation.The application of adenosine triphosphate effectively counteracted the hydroxy-proline-induced inhibition of elongation; completely in water, and partially in indole-3-acetic acid. Optimal ATP concentrations were between 0.25 and 0.75 mm. Similarly, guanine-HCL, l-glutamic acid, and l-ornithine-HCL were capable of reversing the hydroxyproline inhibition. Other compounds that were tested but which proved to be less effective are tabulated.It is suggested that hydroxyproline may exert its inhibitory effect on the protein and/or RNA synthesis necessary for elongation of the oat coleoptile by interference with the metabolism of adenosine triphosphate or other high energy compounds.

Journal Article↗