Authors:Márta Péntek, László Gulácsi, Edit Tóth, Petra Baji, Valentin Brodszky, and Csaba Horváth
cortecosteroid-induced osteoporosis [ Reumatológiai és Fizioterápiás
Szakmai Kollégium: NEFMI szakmai protokoll a korral járó és a
kortikoszteroidok indukálta osteoporosis diagnosztikájáról és terápiájáról
Neutron activation analysis provides a useful clinical test to assess bone mass status in vivo. The neutron flux is obtained from Pu/Be sources and49Ca activity is measured by NaI detectors. For diagnostic value, the49Ca measurement is related to the mean value for normal subjects of the same body size. This normalized index, our CaBI, is used extensively to diagnose the bone loss associated with osteoporosis and to asses changes in bone mass with progression of disease and in response to treatments. Our facility operates at maximum capacity (35 tests/wk.). The hospital location and the dependability and ease of operation (provided by neutron sources) have facilitated extensive clinical use.
Authors:J. Harrison, S. Krishnan, C. Muller, A. Strauss, S. Mukherjee, and W. Sturtridge
The accuracy of dual energy X-ray absorptiometry (DEXA) for measurement of bone mass carried out by quantitative digital radiography (Hologic Inc.) was compared to results with neutron activation analysis (NAA) on 106 subjects. The accuracy with DEXA was further investigated by measurements on aluminium samples of known composition. DEXA measured 4 lumbar vertebrae by spine scan. The central third of the skeleton also was measured by whole body scan to obtain data on the same large part of the skeleton as measured by NAA. Results suggested that DEXA spine scans were more reliable than whole body scans. In addition, the measurement of total mineral content (BMC) was more reliable than the normalization of BMC to bone surface area (BMC/Area) or bone mineral density (BDM). Since the proportion of bone below detection would increase with development of osteoporosis, with osteoporosis the BMC would be increasingly underestimated, but to only a small extent, while the BMD would be more significantly overestimated.
The osteoporosis is regarded as a widespread disease all over the world. In the prevention therapy of this disease there is
a primary role of the daily calcium intake with the proper Ca:P ratio (1:1–1:2). The primary source of Ca for people the dairy
products are implied, from which only the processed cheeses have inadequate ratio of Ca:P. In cheeses processed without peptization
developed in the Hungarian Dairy Research Institute (HDRI) the Ca:P ratio meets the requirements (1.5:1), moreover these products
can be enriched with Ca.
In this study we used both processing technologies. The electronmicroscopic photographs demonstrate the differences clearly.
The traditionally processed cheese (with peptization) has a 'spongy’ structure well known from literature, while a space-net
can be seen resulting from the casein-filamentous hydrocolloid interaction in the structure of heat-treated cheese without
peptization. DSC curves are the same in the temperature range 0–40C, showing endotherm melting process in two well-distinguished
temperature interval (0–20 and 22–40C). They are different in the temperature interval 40–100C: in the case of processed
cheese with peptization the gel-sol transformation gives a higher endotherm peak in a narrow temperature range, while for
heat-treated cheese without peptization this temperature range is wider with a lower endotherm peak.
Both electronmicroscopic and DSC investigations have proved that contrary to the traditionally processed cheese where the
structure is formed by the linked peptized protein, in the heat- processed cheese without peptization the frame-forming element
is the huge hydrocolloid molecule interacted with the protein. The enthalpy change is substantially lower at the disintegration
of the latter structure.