Spatial distribution analysis of strontium in human teeth by laser-induced breakdown spectroscopy: application to diagnosis of seawater drowning

Medical application of laser-induced breakdown spectroscopy (LIBS) for assessment of trace element and mineral in biosamples: Laboratory and clinical validity of the method

BACKGROUND

Biomedical application is based on the use of LIBS-derived data on chemical contents of tissues in diagnosis of diseases, forensic investigation, as well as a mechanism for providing online feedback for laser surgery. Although LIBS has certain advantages, the issue of correlation of LIBS-derived data on chemical element content in different human and animal tissues with other methods, and especially ICP-MS, remains pertinent. The objective of the present review was to discuss the application of laser-induced breakdown spectroscopy (LIBS) for elemental analysis of human biosamples or tissues from experimental models of human diseases.

METHODS

A systematic search in the PubMed-Medline, Scopus, and Google Scholar databases using the terms laser-induced breakdown spectroscopy, LIBS, metals, trace elements, minerals, and names of particular chemical elements was performed up through 25 February, 2023. Of all extracted studies only those dealing with human subjects, human tissues, in vivo animal and in vitro cell line models of human diseases were reviewed in detail.

RESULTS

The majority of studies revealed a wide number of metals and metalloids in solid tissues including teeth (As, Ag, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Ni, P, Pb, Sn, Sr, Ti, and Zn), bones (Al, Ba, Ca, Cd, Cr, K, Mg, Na, Pb, Sr), and nails (Al, As, Ca, Fe, K, Mg, Na, P, Pb, Si, Sr, Ti, Zn). At the same time, LIBS was also used for estimation of trace element and mineral content in hair (Ca, Cu, Fe, K, Mg, Na, Zn), blood (Al, Ca, Co, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Si, Sn, Zn), cancer tissues (Ca, Cu, Fe, Mg, K, Na, Zn) and other tissues. Single studies revealed satisfactory correspondence between quantitative LIBS and ICP-OES/MS data on the level of As (81-93 %), Pb (94-98 %), Cd (50-94 %) in teeth, Cu (97-105 %), Fe (117 %), Zn (88-117 %) in hair, Ca (97-99 %), Zn (90-95 %), and Pb (61-82 %) in kidney stones. LIBS also estimated specific patterns of trace element and mineral content associated with multiple pathologies, including caries, cancer, skin disorders, and other systemic diseases including diabetes mellitus type 2, osteoporosis, hypothyroidism, etc. Data obtained from in situ tissue LIBS analysis were profitably used for discrimination between tissue types.

CONCLUSIONS

Taken together, the existing data demonstrate the applicability of LIBS for medical studies, although further increase in its sensitivity, calibration range, cross-validation, and quality control is required.

Combining Oxidative Stress Markers and Expression of Surfactant Protein A in Lungs in the Diagnosis of Seawater Drowning

BACKGROUND AND OBJECTIVES

The diagnosis of seawater drowning (SWD) remains one of the most complex and contentious. It is one of the leading causes of unintentional death around the world. In most cases, the forensic pathologist must reach an accurate diagnosis from the autopsy findings and a series of complementary tests such as histopathological, biological, and chemical studies. Despite the lung being the most affected organ in death by submersion, there are few studies on this type of death's impact on this organ. The aim was to investigate human lung cadavers of forensic cases due to different causes of death, the concentration of the oxidative stress markers malondialdehyde (MDA) and γ-glutamyl-l-cysteinyl glycine (GSH), and the relationship with the expression of surfactant protein A (SP-A) to try to discriminate SWD from other types of causes of death.

MATERIALS AND METHODS

A total of 93 forensic autopsy cases were analyzed. Deaths were classified into three major groups based on the scene, cause of death, and autopsy findings (external foam, frothy fluid in airways, overlapping medial edges of the lungs): (a) drowning in seawater (n = 35), (b) other asphyxia (n = 33), such as hangings (n = 23), suffocations (n = 6), and strangulation (n = 4), and (c) other causes (n = 25), such as multiple suffocations. Oxidative stress markers (MDA and GSH) and the immunohistochemical expression of SP-A were determined in both lungs.

RESULTS

MDA levels were statistically higher in both lungs in cases of SWD than in other causes of death (p = 0.023). Similarly, significantly higher levels of GSH were observed in SWD compared to the rest of the deaths (p = 0.002), which was more significant in the right lung. Higher immunohistochemical expression of SP-A was obtained in the cases of SWD than in the other causes of death, with higher levels in both lungs. The correlation analysis between the levels of oxidative stress (MDA and GSH) in the lung tissue and the expression level of SP-A showed positive and significant results in SWD, both in the alveolar membrane and the alveolar space.

CONCLUSIONS

Determining the levels of MDA and GSH in lung tissue and the expression level of SP-A can be of great importance in diagnosing SWD and the circumstances of death. A better understanding of the physiology of submersion is essential for its possible repercussions in adopting measures in the approach to patients who have survived a submersion process. It is also necessary for forensic pathology to correctly interpret the events that lead to submersion.

Trace elements in forensic human lung: A new approach to the diagnosis of seawater drowning. A preliminary study

The diagnosing of drowning remains one of the most challenging activities for the forensic pathologist. There is little information on the impact on the lung as a target organ in death by drowning. We aimed to investigate the concentration of trace elements in the lungs of people who had suffered different types of death to evaluate the discriminating ability of trace elements to identify seawater drowning (SWD). A total of 11 trace elements were analyzed by Inductively Coupled Plasma-Mass Spectrometry in 74 forensic cases. Sampler scanning electron microscopy and Energy Dispersive X-ray spectroscopy (EDX) were used to identify ultrastructural lung alterations. A Principal Component Analysis (PCA) of trace elements was carried out. The trace elements in SWD lungs were detected in the following order of concentration: Br˃Zn˃Sr˃Cr˃Cu˃As˃Pb˃Se˃Mn˃Ni˃Cd. Our results showed significantly higher concentrations of Br and Sr (P = 0.010 and P = 0.000) and significantly lower concentrations of Zn, Pb, Cu, Cd, and Se in SWD compared with other causes of death. After adjusting by confounder factors, Sr and Br remained as predictive independent factors for diagnosis of drowning (p = 0.042, in both cases). These results were confirmed by PCA, which revealed a wide separation between SWD and the rest of the causes of death. Our SWD cohort was characterized by high concentrations of the trace elements Br and Sr and low concentrations of Zn, Pb, Cu, Cd, and Se in lung tissue, while PCA showed its discriminatory capacity to identify death by seawater drowning. These findings, together with those obtained using other techniques, can be of great importance in the diagnosis of SWD.

After bleaching enamel remineralization using a bioactive glass-ceramic (BioSilicate®)

Tooth bleaching agents may weaken the tooth structure, therefore, it is important to minimize any risks of enamel and dentine damage caused by them. In this way, different materials have been used to avoid or minimize the tooth damage during bleaching. Recently, bioactive glasses have been demonstrated to be effective in mineralization of dental structures. Therefore, this study evaluated the effect of BioSilicate® (a polycrystalline bioactive glass-ceramic) after bleaching by Laser-induced breakdown spectroscopy (LIBS) technique. Bovine dental blocks with 4 × 4 × 3 mm were obtained (n = 20), sequentially embedded in epoxy resin and then polished. Bleaching was performed using 35% hydrogen peroxide (Whiteness HP). Calcium (Ca) and phosphate (P) intensity values by LIBSwere obtained before the treatment (T0, baseline – control Group), after bleaching (T1), and after BioSilicate® application (T2). The use of BioSilicate® after bleaching showed to be an optimal way to remineralize enamel surface making BioSilicate® application a promising adjunct step to avoid or minimize the mineral loss on enamel surface after bleaching.