Background -Recent reports have suggested short term changes in serum parameters of bone metabolism with inhaled corticosteroids. The relevance of these findings to the balance between bone formation and resorption during years of corticosteroid treatment remains uncertain. Methods -Two novel markers of bone turnover were first compared with conventional markers in a pilot study and subsequently measured in a long term double blind study of inhaled corticosteroids. In study I 15 patients were newly started on at least 800 tg inhaled corticosteroids daily. At entry and after four weeks serum levels of alkaline phosphatase, osteocalcin, and PICP (procollagen type I carboxy terminal propeptide; a procollagen splice product) were measured as markers of bone formation, as well as the urinary hydroxyproline/ creatinine ratio and serum levels of ICTP (type I collagen carboxy terminal telopeptide; a collagen degradation product) as markers of bone resorption. In study II 70 patients with airways obstruction received 800 jg beclomethasone daily in addition to terbutaline and 85 received bronchodilators only in a double blind fashion. Serum levels of PICP and ICTP were measured before and after 2 5 years of treatment. Results -In study I a decrease in osteocalcin levels was accompanied by an increase in levels of PICP and a small and non-significant rise in alkaline phosphatase. There were no changes in hydroxyproline or ICTP. In study II no differences were found in serum levels of PICP between the treatment groups; an increase in serum ICTP was found in the group treated without inhaled corticosteroids compared with the group treated with inhaled corticosteroids. Conclusions -No detrimental long term effect of inhaled corticosteroids was found with three conventional and two novel parameters of bone metabolism. The results indicate that long term changes in bone turnover during treatment with inhaled corticosteroids should not be deduced from short term studies with single serum parameters of bone metabolism, but well designed long term studies of, for example, bone densitometry should be awaited before quoting detrimental effects of inhaled corticosteroids on bone metabolism. (Thorax 1994;49:652-656) Inhaled corticosteroids are currently administered to more patients with asthma and chronic obstructive pulmonary disease (COPD), at an earlier stage, and in higher dosages than previously.'13 Long term use of inhaled steroids has been shown to reduce exacerbations and hospital stay and to delay further deterioration of lung function.3 As far as current knowledge goes, however, this requires patients to take inhaled corticosteroids 2-4 times daily for many years. Although the short term direct adverse effects of inhaled corticosteroids seem to be acceptable, there is increasing discussion of possible adverse effects after years of usage.One of the important adverse effects of oral corticosteroids is osteoporosis, eventually leading to fractures.4 A few studies on the effects of inhaled corticosteroids on bone tu...
Sulphated lithocholic acid conjugates (SGLC) were measured in the sera of 268 children with various hepatic and intestinal disorders. Two groups were distinguished: (I) SGLC concentration less than or equal to 1.2 mumol/l, n = 198, and (II) SGLC concentration greater than 1.2 mumol/l, n = 70. In 28 patients of the latter group the SGLC concentration was less than 25% of the concentration of glycocholic acid (GC) in the same serum sample. This group (IIA) consisted predominantly of patients with cholestasis, as characterized by high serum bile acid levels and deviating liver function tests. The rest of the group (IIB), with SGLC levels exceeding 25% of the GC concentration and relatively low serum bile acid concentrations, showed no clear cholestatic symptoms. A postprandial increase in serum SGLC (delta SGLC) greater than 1.0 mumol/l was found in only 1 of 32 patients of group I (3%), in 1 of 6 patients of group IIA (17%), but in 9 of 11 patients of group IIB (81%). delta SGLC did not correlate with delta GC in the same test, which indicated that a general hepatic bile acid clearance defect was not responsible. In two patients with intermittent cholestasis, the distinct postprandial rise in serum SGLC that was always found during anicteric periods could be prevented by adding cholestyramine to the test meal. We conclude that elevated serum concentrations of SGLC develop during the course of cholestasis but may also be caused by influx of this bile acid from the intestine. Because of its hepatotoxic properties, SGLC may be involved in the initiation or perpetuation of specific cholestatic phenomena.
The level of the aminoterminal propeptide Col 1-3 of type III procollagen (PC-III) was determined in patients with paroxysmal nocturnal haemoglobinuria (PNH) and primary myelofibrosis (PMF), to study whether PC-III can be used as a parameter for the rate and/or degree of bone marrow replacement with collagen. Normal PC-III levels were found in PNH (6.6 +/- 1.1 micrograms/l; N: 8.6 +/- 1.8 micrograms/l), while significantly increased levels were found in PMF (24.8 +/- 2.2 micrograms/l). During a follow-up of 1 year, a slight increase of 2 micrograms/l occurred in three patients with a stable fibrosis, while one patient with more active disease demonstrated an increase of 25 micrograms/l. Treatment with acetylsalicylic acid led to a decline of PC-III as well as beta-thromboglobulin level, although normalization did not occur. It was demonstrated by means of gel filtration that the antigens related to the PC-III peptide were heterogenous, and that in PMF at least two main peaks were present, with molecular masses equal to and smaller than PC-III peptide. These data demonstrate that the radioimmunoassay cannot be used for the quantitative determination of PC-III; nevertheless it gives some insight in the process of bone marrow fibrosis.
We evaluated renal 131I-hippurate clearance (ERPFhip) as a measure of renal blood flow (RBF) in chronically instrumented conscious dogs. When adjusted for renal hippurate extraction (Ehip, 0.77 +/- 0.01) and hematocrit (Hct, 39.7 +/- 1%), calculated RBFhip (656 +/- 37 ml/min) markedly exceeded renal blood flow measured with renal artery blood flow probes (RBFprobe, 433 +/- 27 ml/min). The discrepancy could not be explained by flow probe calibration, because in vivo comparison of flow probe values with renal venous outflow showed only a slight underestimation of renal blood flow (slope 0.93, 95% confidence interval 0.89-0.97). Redistribution of hippurate from erythrocytes into renal venous plasma during or shortly after blood sampling led to an underestimation of Ehip by 4 +/- 1% and thus could only explain a small part of the difference. Extrarenal hippurate clearance was excluded, because the amount of 131I-hippurate cleared from plasma equaled that appearing in the urine (303 +/- 17 and 307 +/- 17 ml/min). Applying these corrections, we found that RBFhip still exceeded RBFprobe by 37 +/- 3%. These data indicate that renal blood flow measured by the hippurate clearance technique markedly overestimates true renal blood flow. Because other errors were excluded, a combination of sampling of nonrenal blood and intrarenal hippurate extraction from erythrocytes might play a role.
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