Analysis of minor and trace elements in gallstones by induction of characteristic ionising radiation

Discrimination of gallbladder stone employing Laser-Induced Breakdown Spectroscopy (LIBS) and Photoacoustic Spectroscopy (PAS)

Compositional analysis of gallstone samples has been carried out, using Laser-Induced Breakdown Spectroscopy (LIBS) and Photoacoustic Spectroscopy (PAS). Classification of gallstone has been made on the basis of intensities of the inorganic and organic constituents present in the LIBS spectra. A regression plot is drawn between LIBS spectral intensities of organic & inorganic elements and the stoichiometric ratio of Cholesterol, Bilirubin and Calcium Carbonate. Atomic lines of various elements, as well as molecular signatures of CaO Orange band, CN Violet band, and C₂ Swan band, are observed in LIBS spectra. The relative hardness of gallstones is estimated from the intensity ratio of ionic to neutral atomic lines of the species observed in LIBS spectra. PAS is used for detecting molecular constituents in the gallstones. Principal Component Analysis (PCA) is performed for the discrimination of gallstones. It is found that PAS data, in combination with LIBS provide a suitable method for the compositional analysis of gallstones.

Analysis of stones formed in the human gall bladder and kidney using advanced spectroscopic techniques

Stone diseases (gallstones and kidney stones) are extremely painful and often cause death. The prime aim of biomedical research in this area has been determination of factors resulting in stone formation inside the gallbladder and urinary tract. Many theories have been put forward to explain the mechanism of stone formation and their growth; however, their complete cycle of pathogenesis is still under debate. Several factors are responsible for stone formation; however, much emphasis is placed on the determination of elemental and molecular composition of the stones. In the present review article, we describe different kinds of spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF) spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and laser-induced breakdown spectroscopy (LIBS) and highlight their use in the analysis of stone diseases. We have summarized work done on gallstones and kidney stones using these advanced techniques particularly over the last 10 years. We have also briefly elaborated the basics of stone formations inside the human body and their complications for a better understanding of the subject.

Microstructural diversity of gallstones revealed by spectral microanalyses and their association with hepatic parameters

BACKGROUND

Gallstones (GS) are formed as a result of impaired metabolic regulation and can be reflected in serum parameters. This study was focused on classifying GS based on spectral microanalysis and identifying the possible role of serum hepatic parameters on GS of different compositions.

METHODS

The study included a total of 126 GS from 80 consecutive patients who underwent cholecystectomy for GS diseases in a single center. The composition and microstructure of GS were analyzed using Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS). The serum hepatic parameters were studied in order to establish a possible etiologic relationship with GS composition.

RESULTS

In the study group, the incidence of GS was higher in females 62 (77.5%) compared with males 18 (22.5%). The mean age was 42.81 ± 13.01 and 43.78 ± 14.4 years for female and male patients, respectively. Based on composition, the GS were assigned to four major groups: cholesterol, pigment, phosphate, and mixed stones. Mixed composition stones totally represented the majority 53 (66.3%), followed by pure cholesterol 23 (28.8%), pigment stones 2 (2.5%), and phosphate stones 2 (2.5%), respectively. Elemental composition revealed the presence of carbon (C), oxygen (O), calcium (Ca), and phosphorus (P) to be major elements along with traces of sodium (Na), magnesium (Mg), aluminum (Al), iron (Fe), copper (Cu), bromine (Br), manganese (Mn), and zinc (Zn). Among serum parameters, total bilirubin, direct bilirubin, indirect bilirubin, serum glutamic-oxaloacetic transaminase, and total protein were higher in patients with pigment GS than cholesterol GS.

CONCLUSIONS

Characterization of GS indicates that different types of stones have different characteristics in terms of microstructure, elemental composition, and distribution. Serum hepatic function test profiles showed an association with the compositions of GS.

Scanning electron microscopy in analysis of urinary stones

Urolithiasis is a frequent and in many cases serious disease. Proper analysis of kidney stone composition is crucial for appropriate treatment and prevention of disease recurrence. In this work, scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy was applied for a study of 30 samples covering the most common types of human kidney stones. The results are analyzed and evaluated in terms of applicability of the method for both routine kidney stone analysis as well as collecting of specific data. The method provides complex information about studied samples including morphology of the stones and of the present crystals or their aggregates. It also brings information on elemental composition of the phases. After application of standardization, quantitative microanalysis with detection limits of 400 ppm (Mg, P, S, Cl, K, Ca), 500 ppm (Na) and 1200 ppm (F) was obtained. Compositional mapping with EDS shows the elemental distribution within a sample. This study demonstrated that information on morphology and chemistry acquired by these methods was highly reliable for identification of phases, even when present in small amounts. It provided information on kidney stone structure, relationships between phases, major and minor element content, and variations in chemical composition related to the growth of the stones. SEM represents a powerful tool in urinary stone analysis, since a single facility can produce a wide spectrum of information. It can be suggested as a basic method used for routine urinary stone identification, whilst bringing additional detailed information that cannot be obtained by other methods.

New insights into the chemical and isotopic composition of human-body biominerals. I: Cholesterol gallstones from England and Greece

We have analyzed gallstones from four patients of Europe and particularly from England (including samples from a mother and a daughter) and Greece. According to the XRD, FTIR, NMR and laser micro-Raman results the studied materials correspond to typical cholesterol monohydrate (ChM). The micro-morphology of cholesterol microcrystals was investigated by means of SEM-EDS. The XRF results revealed that Ca is the dominant non-organic metal in all gallstones (up to ∼1.95wt.%) together with Fe, Cu, Pb and Ni (up to ~19ppm for each metal). Gallstones from England contain additional Mn (up to ~87ppm) and Zn (up to ∼6ppm) while the sample of the mother contains negligible Zn and Mn, compared to that of her daughter, but significant As (~4.5ppm). All cholesterol gallstones examined are well enriched in potentially toxic metals (Pb, as well as Ni in one case) and metalloids (As also in one case) as compared to the global average. The position of Zn, which is a characteristic biometal, in the structure of cholesterol, was investigated by molecular simulation using the Accelrys Materials Studio(®) software. On the basis of IRMS results, all gallstones examined exhibit a very light δ(13)C signature (average δ(13)C ~-24‰ PDB). Gamma-ray spectrometry measurements indicate the presence of (214)Pb and (214)Bi natural radionuclides due to the (238)U series as well as an additional amount of (40)K.

COMPARATIVE STUDIES OF TRACE ELEMENTS IN TWO KINDS OF HUMAN GALLSTONES

Structural composition of 11 trace elements with Z greater than 13 ( Al , P , Si , K , Ca , Mn , Fe , Cu , Zn , Mo , I ) was analyzed for the two main groups of human gallstones according to their cholesterol and pigment types by PIXE (Proton Induced X - ray Emission). In both types of stones, the shell and the center were analyzed separately. The gallstones were obtained from 12 patients in wide age group from 22 to 78 years of age during surgical operation. The results show relatively higher values of heavy elements for ages greater than 40. The values of phosphorous in cholesterol type stones are significantly higher than in those of pigment stones. The concentration of calcium in the center of stones is large in comparison with that in the shells. In this paper, a correlation between stone structure and trace elemental concentration has been presented. Comparison of the two essential types of stones (cholesterol and pigment) shows that the center of the pigment stones is very similar to that of the cholesterol type.

Quantitative analysis of gallstones using laser-induced breakdown spectroscopy

The utility of laser-induced breakdown spectroscopy (LIBS) for categorizing different types of gallbladder stone has been demonstrated by analyzing their major and minor constituents. LIBS spectra of three types of gallstone have been recorded in the 200-900 nm spectral region. Calcium is found to be the major element in all types of gallbladder stone. The spectrophotometric method has been used to classify the stones. A calibration-free LIBS method has been used for the quantitative analysis of metal elements, and the results have been compared with those obtained from inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements. The single-shot LIBS spectra from different points on the cross section (in steps of 0.5 mm from one end to the other) of gallstones have also been recorded to study the variation of constituents from the center to the surface. The presence of different metal elements and their possible role in gallstone formation is discussed.

[Crystalline microstructure and microanalysis of gallstones in childhood and adolescence]

OBJECTIVES

To determine the crystalline structure and chemical composition of gallstones in children and adolescents. Design of the studyA simple descriptive study was performed in 21 gallstones from pediatric patients with chronic cholecystitis who underwent elective cholecystectomy. Only two patients had an underlying disease that could explain the presence of gallstones. Crystalline structure was determined by X-ray diffraction and visualization with scanning electron microscopy. Emission and atomic absorption spectroscopy were used to study composition. An X-ray-dispersion energy spectroscope joined to the microscope was used to confirm the crystalline composition of some of the areas examined with the microscope.

RESULTS

Bilirubinate and calcium carbonate predominated in the crystalline composition, demonstrating the pigmented appearance of idiopathic gallstones. Cholesterol was a secondary element. Microanalysis confirmed calcium as a fundamental constituent of gallstones irrespective of age. Other elements, such as sodium, potassium, magnesium and manganese, etc., were detected.

CONCLUSIONS

The present study confirms the pigmented character of idiopathic gallstones in childhood. The high levels of calcium carbonate and bilirubinate, despite a lack of evidence for any risk factors for the formation of bilirubinate, was striking. Calcium was the most predominant element of the calculi.

Developments in tomographic methods for biological trace element research

Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and distribution of elements in a selected plane through a biological specimen is briefly explained and applied by way of illustration to the analysis of gallstones. A system capable of carrying out studies of the binding site of 75Se is different matrices using time differential perturbed angular correlation spectroscopy is also briefly described. Developments in the detector technology of positron emission tomography have allowed small-diameter imaging devices to be built for in vivo preclinical evaluation of new tracers in small animals and are discussed in the context of a proposed experiment combining the techniques mentioned above.