Original article 999 Analysis of Indian cholesterol gallstones by particle-induced X-ray emission and thermogravimetry–derivative thermogravimetry Tapash R. Rautray a,b , Venkatathri Vijayan b and Simanchalo Panigrahi a Objectives It has been reported that the role of some minor elements plays a significant role in the formation of gallstones. The relationship between minor and trace element concentrations was established in the present investigation and the trace element profile of the current investigation was compared with the literature values of south Indian gallstone samples in order to determine their possible role in stone formation and growth. The rate of weight loss and classification of cholesterol type of gallstones were also investigated by thermal analysis. Basic methods The trace element profile of the cholesterol gallstones was determined by proton-induced X-ray emission spectroscopic technique and the thermal properties of the cholesterol stones were studied by thermogravimetry–derivative thermogravimetry analysis. Results It was observed that 14 minor/trace elements, namely S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb, were present in the cholesterol stone samples. The average concentration of Fe in south Indian (Chennai region) gallstone samples (503.4 ppm) is about 2.5 times more than that of the east Indian gallstone samples (205.0 ppm), whereas the concentration of Fe is still higher in other parts of south India (848.2 ppm) as analysed by Ashok et al. Conclusions The higher concentration of Cu (in some parts of south India except the Chennai region) and Fe in south Indian cholesterol stone samples may be due to the intake of tamarind (Garcinia camborginia) as their regular food. The thermogravimetry and derivative thermogravimetry curves provided information on the thermal decompositions of cholesterol stones. Eur J Gastroenterol Hepatol 18:999–1003  c 2006 Lippincott Williams & Wilkins. European Journal of Gastroenterology & Hepatology 2006, 18:999–1003 Keywords: calcium carbonate, crystallization, ion beam a Department of Physics, NIT, Rourkela and b Institute of Physics, Bhubaneswar, Orissa, India Correspondence and requests for reprints to Venkatathri Vijayan, Institute of Physics, PO-Sainik School, Bhubaneswar 751005, Orissa, India Tel: + 91 674 2301058/ + 91 674 2300637; fax: + 91 674 2300142; e-mail: vijayan@iopb.res.in Received 16 August 2005 Accepted 26 April 2006 Introduction Gallstones consist mainly of organic compounds such as cholesterol, bilirubin, bile acid and fatty acid. They are broadly classified into three categories according to their composition namely cholesterol type (cholesterol rich), pigment type (bilirubin and calcium bilirubinate rich) and mixed type (combination of cholesterol, calcium carbonate, calcium bilirubinate). Cholesterol gallstones are formed owing to supersaturated bile while the black pigment gallstones are common in haemolytic anaemia in the presence of infected bile [1]. Factors responsible for the formation of gallstones include altered hepatic bile composition, biliary glycoprotein, infection, age, genetic factors, sex, oestrogen, dietary factors, geographical prevalence and cirrhosis of the liver [2]. The homeostatic regulation of trace elements existing as positively charged cations (e.g. Cu, Fe, Zn) occurs primarily during absorption from the gastrointestinal tract. Trace elements absorbed as negatively charged anions (e.g. boron, selenium) are usually absorbed freely and completely from the gastrointestinal tract. Thus, they are homeostatically regulated primarily by excretion through urine, bile, sweat and breath [3]. Elements such as Cu and Zn are excreted from the liver via bile. In addition, it has been reported that the role of some minor elements is significant in the formation of gallstones. The relationship between minor and trace element concentrations and the occurrence of various gallstone diseases and health conditions has long been of interest in medicine [4]. Both deficiencies and excesses of the concentration of these trace elements may result in a number of disorders in the human body. On the other hand, the toxic elements are known to be very harmful even at extremely low concentration. As proton-induced X-ray emission (PIXE) is simulta- neous, reliable, rapid, multi-elemental, sensitive and non-destructive in nature to analyse even the few parts per million level elements [5], the present investigation was carried out for cholesterol gallstone samples. Moreover, to know more about the thermal properties, thermogravimetry–derivative thermogravimetry (TG– DTG) analysis has been performed for the cholesterol 0954-691X  c 2006 Lippincott Williams & Wilkins Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.