Hydrochlorothiazide lowers urinary hydroxyproline in parathyroidectomized rats

This study was undertaken to examine the effects of hydrochlorothiazide treatment on urinary hydroxyproline excretion in parathyroidectomized rats. Urinary hydroxyproline (mumol/24 hr) fell significantly in thiazide-treated rats compared with control animals (5.66 +/- 0.37 versus 7.30 +/- 0.6, P less than 0.05, means +/- SEM). This fall in hydroxyproline excretion occurred without a decrease in glomerular filtration rate. It is concluded that the ability of thiazide diuretics to reduce urinary hydroxyproline excretion is not dependent upon suppression of parathyroid hormone-mediated bone turnover.     

Paget's disease of bone: early and late responses to three different modes of treatment with aminohydroxypropylidene bisphosphonate (APD).

Early and late responses to treatment with either oral (600 mg/day) or intravenous (20 mg/day) (3-amino-1-hydroxypropylidene)-1,1-bisphosphonate (aminohydroxypropylidene bisphosphonate; APD) were studied in 142 patients with Paget''s disease of bone who had not previously been treated with bisphosphonate. The efficacy of three therapeutic regimens was compared: (a) oral aminohydroxypropylidene bisphosphonate given continuously until six months after the serum alkaline phosphatase activity had returned to normal (long term); (b) oral aminohydroxypropylidene bisphosphonate given until urinary hydroxyproline excretion had returned to normal (short term); (c) intravenous aminohydroxypropylidene bisphosphonate for 10 days. With either oral or intravenous treatment the decrease in urinary hydroxyproline excretion was rapid and always preceded the fall in serum alkaline phosphatase activity. Normal urinary hydroxyproline excretion is essential for return of the serum alkaline phosphatase activity to normal. Complete biochemical remission, defined as return of the serum alkaline phosphatase activity to normal, was obtained in 129 patients (91%). The median duration of remission as assessed by actuarial analysis was 2.7 years. This study found no difference in the long term among the three modes of treatment, suggesting that for most patients with Paget''s disease a short course of intravenous aminohydroxypropylidene bisphosphonate will produce longlasting, complete remission without need for maintenance treatment.     

Paget's Disease in a 5-year-old: Acute Response to Human Calcitonin

A five-year-old boy presented with a three-and-a-half-year history of repeated bone fractures and progressive bone deformity. The excretion of hydroxyproline in the urine was greatly increased, and serum alkaline phosphatase and acid phosphatase levels were very high. These abnormalities together with the findings on bone histology and radiology suggested a diagnosis of juvenile Paget''s disease. Human calcitonin reduced the bone turnover as evidenced by an immediate and sustained fall in urine hydroxyproline excretion, while calcium and phosphate balance became more positive. This treatment is therefore being continued on an outpatient basis.     

Hydroxyproline metabolism in two sisters with hydroxyprolinemia

Hydroxyproline metabolism was evaluated in two sisters with hydroxyprolinemia and their mother. 33 and 21% of an oral hydroxyproline load (200 mg/kg) was excreted by the sisters, 5.4% by the mother, and 1.3% by normal subjects. Plasma and erythrocyte values in the sisters and their mother were elevated, indicating that extra- and intracellular hydroxyproline pools were increased. Analysis for urinary glycolate and oxalate (metabolic products of hydroxyproline) showed no increased excretion by the two sisters, although the mother's excretion was normal. A deficiency of hydroxyproline oxidase in the two sisters was indicated by the lack of delta 1-pyrroline-3-hydroxy-5-carboxylic acid excretion.     

Oestradiol inhibits collagen breakdown in the involuting rat uterus

1. The earlier observation (Woessner, 1969) of oestradiol inhibition of collagen breakdown is confirmed and extended. Administration of 100mug of oestradiol-17beta/day to parturient rats strongly inhibits the loss of collagen from the involuting uterus. Three experiments show that this effect is due to an inhibition of collagen degradation rather than to a stimulation of collagen synthesis. 2. Uterine collagen was labelled with hydroxy[(14)C]-proline by the administration of [(14)C]proline near the end of pregnancy. By 3 days post partum, control uteri lost 83% of their collagen and 90% of their hydroxy[(14)C]proline. Uteri from oestradiol-treated rats lost only 50% of both total and labelled hydroxyproline, with no decrease in the specific radioactivity of the hydroxyproline. 3. Incorporation of [(14)C]proline into uterine collagen hydroxyproline in vivo was not affected by oestradiol treatment. 4. Urinary excretion of hydroxyproline was increased in post-partum control rats and decreased in oestradiol-treated rats. 5. An enzyme capable of cleaving 4-phenylazobenzyloxycarbonyl-l-prolyl-l-leucylglycyl- l-prolyl-d-arginine (a substrate for clostridial collagenase) increased in activity in the post-partum uterus and was unaffected by oestradiol treatment. 6. Uterine homogenates digested uterine collagen extensively at pH3.2. This digestion was unaffected by the oestradiol treatment. 7. Lysosomal fractions prepared by density-gradient centrifugation of uterine homogenates contained coincident peaks of cathepsin D activity and peptide-bound hydroxyproline. The cathepsin D and hydroxyproline contents of this peak were unaffected by oestradiol treatment.     

Toxicological effects of an organophosphorus pesticide (dimethoate) on urinary collagen metabolites in normal and high protein diets fed female albino rats

The effect of an organophosphorus pesticide (dimethoate) on the urinary excretion of hydroxyproline (total, nondialysable, dialysable and free fractions) and hydroxylysylglycosides, glucosylgalactosyl hydroxylysine and galactosehydroxylysine was investigated in two groups of female albino rats fed with normal and high protein diets. In comparison to controls, dimethoate treated animals were found to excrete significantly decreased amounts of urinary hydroxyproline fractions from 7th day onwards. The excretion of total hydroxylysylglycoside in urine parallels the excretion of hydroxyproline. The urinary output of both glu-gal-hyl and gal-hyl was also appreciably lower from dimethoate treated animals. The normal ratio of glu-gal-hyl and gal-hyl found in the urine of dimethoate treated animals was discussed in light of decreased turn over of collagen in both bone and skin. The effect of dimethoate in rats fed with high protein diet was comparatively less than those fed with normal diet.     

Influence of bleomycin on the metabolism of dermal collagen in albino rats

The metabolism of collagen in male rats by treatment with bleomycin was studied following the injection of [3H]proline and the determination of specific and total activity of [3H]hydroxyproline in skin collagen fractions and urine. In the case of the bleomycin-treated animals, there was found to be an increase in the neutral salt soluble collagen content with no change in insoluble collagen content as compared to the control group. The specific and total radioactivity of [3H]hydroxyproline in soluble and insoluble collagen fractions was also increased. Examination of [3H]hydroxyproline activity in soluble and insoluble collagen showed that the conversion of soluble to insoluble collagen was improved by the bleomycin-treated group. It was found that this was accompanied by a decrease in urinary excretion of total hydroxyproline and [3H]hydroxyproline during the first 12 hr after the administration of [3H]proline. Therefore, the results of the present investigation clearly indicate that the maturation of soluble to insoluble collagen is promoted and accompanied by a decrease in the catabolism of soluble collagen in the bleomycin-treated animals. In addition, administration of bleomycin increased the synthesis of collagen.     

Urinary excretion of pyridinium crosslinks: a new marker of bone resorption in metabolic bone disease

The pyridinium derivatives hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are intermolecular crosslinking compounds of collagen which are only present in its mature form. Contrasting to the wide distribution of type I and II rollagens, HP and LP are absent from skin, ligament and fascia, and their major sources are bone and cartilage. Using a specific HPLC assay, we have determined the 24-h excretion of HP and LP crosslinks in normal adults of both sexes, in patients with primary hyperparathyroidism and in patients with Paget's disease of bone before and after intravenous treatment with aminopropylidene bisphosphonate (APB). Mean adult normal values were 33 ± 13 pmol/μmol creatinine for HP and 6.3 ± 3.4 pmol/μmol creatinine for LP. In women, menopause induced a 2–3-fold increase of HP and LP reflecting the well documented postmenopausal increase of bone turnover. In the urine of patients with primary hyperparathyroidism and of patients with active Paget's disease of bone, urinary crosslinks were significantly higher than in age-matched controls, with a mean 3- and 12-fold increase, respectively. Urinary excretion of hydroxyproline is a well recognized but poorly sensitive marker of bone turnover, reflecting resorption. In the same patients, the effect of menopause and disease state on hydroxyproline excretion was much less dramatic than on HP and LP. During intravenous APB treatment of pagetic patients, there was an early decrease of HP and LP, which was significant after 24 h and reached 62% at 4 days, contrasting with a late and milder decrease of urinary hydroxyproline. Because APB is a potent inhibitor of resorption which does not have a direct short-term effect on bone formation, these data also indicate that urinary excretion of HP and LP reflect only coilagen degradation occurring during osteoclastic resorption and not the degradation of newly synthesized collagen. We conclude that urinary HP and LP excretion represents the firs sensitive and specific marker of bone resorption. Its use should be valuable in the clinical investigation of metabolic bone diseases, especially osteoporosis.     

Different Tissue Uptake after Administration of Proline and Hydroxyproline in Neonatal Piglets

Using whole body autoradiography and impulse counting technique, distribution of intramuscularly administered 14C-DL-hydroxyproline and 14C-L-proline in newborn piglets was compared. The main excretion route of hydroxy-proline was via the kidneys. Hydroxyproline or its metabolic products were excreted at quite another rate by the liver than was proline. Skeletal muscles and myocardium showed a lowered ratio of proline to hydroxyproline. A difference in favour of hydroxyproline in passing the blood-brain barrier was shown. Contrary to proline hydroxyproline yielded a low 14C-level in the skeletal tissues. The possibilities of an incomplete hydroxylation of proline as an aetiological factor in the origin of skeletal disorders are discussed.     

Potential biomarkers of exposure and effect among glass craftsmen and braziers exposed to nitrogen oxides

The purpose of this research was to determine occupational exposure of glass craftsmen and braziers to inhaled nitrogen oxides nitrogen dioxide and nitric oxide and to relate this to urinary nitrate, hydroxyproline and thioethers and to breath pentane. The glass craftsmen were exposed to nitrogen oxides at levels exceeding the occupational exposure standard and higher than braziers or controls. Urinary nitrate excretion was elevated. In these exposed workers hydroxyproline, thioethers and breath pentane were all elevated compared with controls and higher than in braziers who were less exposed. There was, however, only a correlation between individual levels of exposure nitrogen oxides in the breathing zone and breath pentane and there were no individual correlations between markers of effect and excretion of nitrate in the urine at the sample time.     

Day-care surgery in British Columbia: a 7-year experience (1968-74).

Twenty-eight patients with symptomatic Paget''s disease of bone were treated with synthetic salmon calcitonin for periods of 9 to 42 months (average, 23 months). Serum alkaline phosphatase concentration and urinary hydroxyproline excretion, which had been elevated before treatment, were decreased by calcitonin treatment in all patients, and some decrease was sustained in 23 in association with variable decreases in pain, heat and stiffness of major joints. Improvement was sustained further in approximately half of these patients; the other half had partial return of symptoms. Calcium absorption was increased in 9 of 10 patients studied; the increase did not correlate with plasma concentrations of parathyroid hormone. The mean endogenous fecal calcium excretion was decreased significantly but there was no significant change in mean urinary calcium excretion. Mean accretion rate of calcium to bone, studied in 10 patients, was decreased by 35% after 6 months of treatment and by a further 23% 1 year later. There was no consistent effect of calcitonin treatment on bone mineral mass. No serious adverse effects of treatment such as allergic reactions were observed. Calcitonin appears to be effective initially in most patients with Paget''s disease of bone, but with long-term treatment resistance may be acquired.     

Selected indicators of calcium-phosphate metabolism in patients with diabetes mellitus

The changes in blood serum concentrations of calcium, magnesium, inorganic phosphate, total activity of alkaline phosphatase and the activity of its bone fraction, as well as urinary excretion of calcium, phosphate, hydroxyproline and oxalate have been measured in 31 patients with insulin-dependent (type I) diabetes, in 31 patients with non-insulin-dependent (type II) diabetes and in 29 healthy subjects in the condition of low-calcium diet. The elevated urinary excretion of calcium, phosphate, hydroxyproline and oxalate, lowered blood serum level of magnesium, and increased total and bone fraction activities of alkaline phosphatase were found in diabetic patients. The urinary excretion of calcium and hydroxyproline, and the activity of bone fraction alkaline phosphatase were significantly higher in patients with type II diabetes than in those with type I diabetes. It was concluded that there is a significant relation between the state of metabolic normalization of diabetes and the degree of biochemical aberrations concerning calcium-phosphate metabolism.     

Comparative Trial of Nutrizym in Chronic Pancreatic Insufficiency

A cross-over trial of pancreatic replacement therapy was carried out in 12 adults with chronic pancreatic insufficiency. The standard enteric-coated preparation, Pancrex V forte, was compared with Nutrizym, which has an enteric-coated core of pancreatic extract and a shell of bromelains—a mixture of proteolytic enzymes derived from the stem of the pineapple.Nutrizym was significantly more effective than Pancrex V forte in improving fat absorption, and reduced faecal weight. Protein digestion was assessed by measuring the urinary excretion of hydroxyproline after a gelatin meal. Nutrizym produced an earlier and significantly higher peak in hydroxyproline excretion than Pancrex V forte, but the cumulative effect was similar. The value of bromelains was investigated by including a period on the Nutrizym core alone. This was similar to Pancrex V forte in improving fat absorption but had less effect on protein digestion, suggesting that the beneficial effect of Nutrizym compared with Pancrex V forte was due to the added bromelains, and not to differences in enzyme content or enteric coating.     

N-Acetyl-beta-glucosaminidase activity and hydroxyproline excretion in liver diseases in alcoholics

In 35 biopsied alcoholic subjects daily hydroxyproline excretion in the urine and NAGL activity in the serum was determined. Hydroxyproline did not correlate with morphological changes but NAGL activity was significantly higher in the group with active fibrosis.     

Preventive effect of malotilate on carbon tetrachloride-induced liver damage and collagen accumulation in the rat.

Malotilate is a new drug suggested for use in chronic liver diseases. It is shown here to prevent liver damage caused by CCl4. The concomitant administration of malotilate with CCl4 significantly decreased hydroxyproline accumulation in the liver, liver prolyl 4-hydroxylase and liver and serum galactosylhydroxylysyl glucosyltransferase activities. However, it had no effect on the daily urinary hydroxyproline excretion or the hydroxyproline content of the skin, liver or lungs in normal young growing rats. It also had no specific inhibitory effect on hydroxyproline synthesis or secretion in fibroblast cultures, and did not affect the amount of procollagen-alpha 1(I)-specific mRNAs in these cultures. Thus it seems to have no direct inhibitory effect on collagen metabolism. In addition to inhibition of liver collagen accumulation, malotilate was also able to prevent the development of morphological changes in the liver such as focal necrosis, fatty infiltration and inflammatory changes. It also normalized almost completely the standard liver-function tests. It is possible that malotilate may prevent excessive collagen deposition by inhibiting the inflammation caused by CCl4-induced liver damage.     

Effects of aldosterone on the urinary excretion of total and non-dialyzable hydroxyproline

In order to explore the role of mineralocorticoids on collagen metabolism, the effects of aldosterone on the urinary excretion of total and non dialyzable hydroxyproline (HYPRO) was studied in rats. The administration of aldosterone in sesame oil, 75 microgram/100 g body weight to adrenalectomized rats maintained on 1% NaCl solution as drinking fluid and 1 mg of cortisone subcutaneously daily, provoked elevation of total and non dialyzable HYPRO in urine (P less than 0.001), when compared to similarly treated adrenalectomized rats receiving sesame oil but no aldosterone. Both groups showed a normal growth curve and had similar urinary excretion of creatinine. The effects of aldosterone are opposed to the known lowering effects of glucocorticoids on HYPRO excretion and may suggest an effect of aldosterone on collagen turnover. Alternatively, aldosterone may modify the metabolism or excretion of HYPRO in an opposite manner to that of glucocorticoids.     

Effect of various beta-adrenolytic drugs and calcium channel blocker (nifedipine) on selected indicators of calcium-phosphorus metabolism in patients with hyperthyroidism and simple goiter

The study was aimed at evaluation of the effect of short-term treatment with one of the six beta adrenolytic drugs (propranolol, metoprolol, atenolol, pindolol, nadolol, acebutolol) and calcium antagonist nifedipine on the values of several parameters of calcium-phosphorus metabolism in 81 patients with hyperthyroidism (14 patients with Graves' disease, and 67 patients with toxic nodular goiter), and 82 patients with simple goiter. The patients studied have been divided into seven groups, each receiving one of the investigated drugs during four days. A significant decrease in the urinary excretion of hydroxyproline was found only in the patients with hyperthyroidism receiving propranolol. This effect of propranolol on hydroxyprolinuria was not related to the degree of lowering of serum T3 concentration observed in these patients.     

Effect of dietary calcium on serum BGP (osteocalcin).

The present study was designed to clarify the effects of dietary calcium (Ca) intake on serum BGP (osteocalcin) levels. Twelve women with a mean age of 21.2 years participated in the study. After one week of normal Ca intake (mean +/- SE, 535 +/- 2 mg/day), a low-Ca diet (163 +/- 1 mg/day) was given for one further week. Additional asparagine Ca (3 g as Ca/day) was also given to half of the subjects. Serum total and ionized Ca concentrations as well as BGP, PTH and 1,25(OH)2D3 were measured at the end of each period. Amounts of Ca and hydroxyproline excreted in urine were also determined. The plasma level of ionized Ca was significantly increased without any change in total Ca in either group. Low and high Ca intake decreased and increased urinary Ca excretion by 28% and 56%, respectively. Serum levels of BGP and 1,25(OH)2D3 were significantly augmented along with a transient increase in urinary hydroxyproline excretion after Ca deprivation. These results suggest that serum BGP is increased after one week of Ca restriction in healthy subjects.     

Urinary desmosine excretion is inversely correlated with the extent of emphysema in patients with chronic obstructive pulmonary disease

An enhanced proteolysis of lung interstitium is key event in the pathogenesis of emphysema, a major constituent of chronic obstructive pulmonary disease. To assess whether urinary desmosine and/or hydroxyproline may be used as a marker of lung destruction we studied urinary excretions of these products in 20 patients with chronic obstructive pulmonary disease and in 19 appropriate controls in 24h urine collection samples. For desmosine measurements, we developed a new indirect competitive enzyme-linked immunosorbent assay. The extent of emphysema was measured in high resolution computed tomography (CT) scans, by considering lung area with CT numbers <-950 Hounsfield units (HU).Urinary desmosine excretion was significantly higher in patients with chronic obstructive pulmonary disease than in controls (294+/-121 microg versus 183+/-93 microg, P=0.003), and was unrelated with both age and smoking habits. In patients with no evidence or only mild emphysema, desmosine excretion values were significantly higher (P=0.006) than those of patients with moderate to severe emphysema. In patients with chronic obstructive pulmonary disease, urinary hydroxyproline excretion was positively correlated with urinary desmosine excretion but on the average, it was not different from that of controls.These data indicate that urinary desmosine is a sensitive biological marker of lung elastin catabolism. The relatively low levels of urinary desmosine observed in patients with severe emphysema may be accounted for a decrease in elastin catabolism due to reduced lung elastin mass. Urinary desmosine may be used to identify subjects at risk of developing emphysema and to assess the efficacy of therapeutic interventions.     

Calcium metabolism in premenopausal women treated by a Gn-RH agonist for uterine myoma

Eleven premenopausal women with uterine myoma who received 300 micrograms of intranasal Gn-RH agonist (buserelin) three times daily for 6 months participated in this study. Serum estradiol, some parameters related to calcium metabolism and bone mineral density of the lumbar vertebrae assessed by quantitative computerized tomography were evaluated prior to, at the end of and 3 months after the treatment. Hypo-estrogenism was sustained during the treatment period. Calcitonin levels decreased rapidly after the first 2 weeks of the treatment and the fasting urinary hydroxyproline to creatinine excretion value increased in 1 month. Both serum alkaline phosphatase and osteocalcin increased slightly during the treatment. The serum m-parathyroid hormone levels showed no significant changes. There was no significant reduction in the mean lumbar vertebral bone mineral content (BMC) at the end of the treatment, but 4 out of 11 cases showed a decrease in BMC, which returned to the pretreatment level in 3 months after the cessation of treatment. From these findings, this therapy appears to have some effects on calcium metabolism during medication, but no adverse ones in the 3 months after treatment.