Practical relevance of prescribing superimposition for determining a frontal sinus pattern match.

A research that tested the methods suitable for comparing ante- and post-mortem radiographic patterns of frontal sinuses concluded that superimposition should be followed as a stringent method for establishing individual identification. We verified the practical relevance of prescribing superimposition by superimposing ante- and post-mortem frontal sinus patterns recorded in case situations as well as simulated ante- and post-mortem of frontal sinus patterns recorded using archived skulls. For superimposition, the wipe facility available in the vision mixer was employed in addition to the mix mode. Ante- and post-mortem radiographic patterns that were available in two earlier cases were not superimposable. Related simulated ante- and post-mortem radiographic patterns of frontal sinuses are superimposable only when the skull that is initially oriented for recording the ante-mortem radiograph is retained in the same posture for recording the post-mortem radiograph also. Once the skull has been removed from the X-ray table, after recording the simulated ante-mortem radiograph, and repositioned for the simulated post-mortem radiograph, even when the intervening time is 1min, the sinus patterns in these radiographs are not superimposable. Superimposition cannot be used as a conditional requirement for side-by-side comparison of radiographic patterns of frontal sinuses.

Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods.

OBJECTIVE: To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster. METHODS: Amoebic liver abscess was experimentally induced in a hamster by injecting 1 × 10(6) of axenically cultured virulent E. histolytica trophozoites (HM1-IMSS strain) into the portal vein. After a week post-inoculation, the hamster was sacrificed and the liver tissue sections were stained with H&E, PAS and IHC stains to detect the amoebic trophozoite. RESULTS: The three stains revealed tissue necrosis and amoebic trophozoites, but with varying clarity. H&E and PAS stained the trophozoites pink and magenta, respectively, however it was difficult to differentiate the stained trophozoites from the macrophages because of their similarity in size and morphology. On the other hand, IHC stain revealed distinct brown appearance of the trophozoites in the infected liver tissues. CONCLUSIONS: It can be concluded that out of the three stains, IHC is the best for identification of E. histolytica trophozoites in tissue sections.

Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess：comparison of three staining methods

Objective: To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster.Methods:Amoebic liver abscess was experimentally induced in a hamster by injecting 1 × 106 of axenically cultured virulent E. histolytica trophozoites (HM1-IMSS strain) into the portal vein. After a week post-inoculation, the hamster was sacrificed and the liver tissue sections were stained with H&E, PAS and IHC stains to detect the amoebic trophozoite. Results: The three stains revealed tissue necrosis and amoebic trophozoites, but with varying clarity. H&E and PAS stained the trophozoites pink and magenta, respectively, however it was difficult to differentiate the stained trophozoites from the macrophages because of their similarity in size and morphology. On the other hand, IHC stain revealed distinct brown appearance of the trophozoites in the infected liver tissues. Conclusions: It can be concluded that out of the three stains, IHC is the best for identification of E. histolytica trophozoites in tissue sections.