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C Lentner

Publications and source records attributed to C Lentner.

12 recordsLinked to original sources
PubMed1977

Bone remodeling and calcium metabolism: a correlated histomorphometric, calcium kinetic, and biochemical study in patients with osteoporosis and Paget's Disease.

The extent to which histomorphometric analysis of bone biopsies correlates with Ca kinetic and biochemical parameters to reflect true bone formation and resorption in adult man remains an unsolved issue. Two groups of patients with either low (osteoporosis), (n = 15) or high (Paget's disease, n = 6) bone turnover were studied before and after sodium fluoride (NaF) and diphosphonate (EHDP) treatment, respectively. Histomorphometry of iliac crest biopsies permitted precise quantitation of the osteoblast layers (SVab), osteoid seams (SVos), the number of osteoclasts (NAocl) and the Howship's lacunae (SVhl). These determinations were correlated with serum alkaline phosphatase (aPh), urinary hydroxyproline (HyPro), Ca accretion rate (Vo+), and Ca mobilization rate (Vo-). In both patient groups bone formation indices were significantly correlated: SVob/Vo+, r = 0.85; SVos/Vo+, r = 0.83; and aPh/Vo+, r = 0.97. Provided that bone matrix formation and mineralization progess at the same rate, bone formation may be assessed by measuring either aPh, Vo+, SVob, or SVos. From these correlations it is not possible to draw any conclusions regarding the absolute "true" value of bone formation, be it in terms of Ca kinetics, alkaline phosphatase, or histomorphometry. However, since Vo+ retains its proportionality to all the other bone formation parameters tested, the so-called "slow exchange," which refers to pure physicochemical Ca exchange processes in the bone mineral, does not perturb Vo+ in an unsystematic way. Vo+ as well as aPh and histomorphometric indices are thus reliable, though not absolute indices of bone formation. Bone resorption indices correlated less well than bone formation indices: NAocl/Vo-, r = 0.68 and SVhl/Vo-, r = 0.63 with both groups. In the osteoporotic group, a negative correlation existed between the empty Howship's lacunae SVhe and Vo+, r = -0.62. Consequently, the overall extent of Howship's lacunae SVhl is influenced both by bone resorption and bone formation. On the other hand, the best correlation of HyPro was with the sum of Vo+ and Vo-, r = 0.97, confirming that HyPro is a sensitive index for the change of bone turnover.

Adult↗
PubMed1975

The metabolic balance technique: a critical reappraisal.

Twenty-six metabolic balance studies (MBS) of Ca, Mg, and P have been conducted in 11 postmenopausal women with osteoporosis and in 4 patients suffering from Paget's disease of bone. Subjects were given a liquid formula diet (LFD) matched as closely as possible to the patient's home diet. Studies lasted for 25 days, separated into 5-day periods by a carmine marker combines with Cr2O3 as continuous fecal marker. The balance studies were combined with a tracer technique using 47Ca to detect a possible loss of Ca by perspiration. The reliability of analytical methods necessary for mineral balances was tested. In 22 of the 26 MBS a steady state (SS) reflecting the patient's regular living conditions was demonstrated, while a non-SS situation possibly due to changes of physical activity was seen in four instances. The overall precision and accuracy of this balance method for Ca and P was found to be better than plus or minus 50 mg/day after four periods and plus or minus 40 mg/day after five periods, as related to an average daily intake of 920 mg Ca and 1230 mg P. For Mg (intake 190 mg/day), a precision of plus or minus 10 mg/day was recorded. The dermal loss of Ca was found to be less than 20 mg/day. As shown for Ca, Mg and P, the precision of a balance study is only little enhanced when the investigation is continued for more than four periods. At the present time is not possible to predict non-SS situations before starting such a study but a simple formula is proposed to detect those which were not performed under SS conditions.

Calcium↗
PubMed1975

[Food analysis for balance studies, especially calcium, magnesium, phosphorus and nitrogen].

The calcium-, magnesium-, phosphorus-, nitrogen- and water-contents have been estimated in raw and processed foods (bread and sausages). These results were then compared with the data in food tables. Surprisingly small differences were recorded, since content-deviations of processed foods are equalized in a whole day menu. Thus, food tables proved to be reliable for the calculation of balance and test diets.

Calcium↗