4-Aminobiphenyl (4-ABP), an aromatic amine is a major environmental carcinogen found mainly in cigarette smoke. It has been vastly implicated in mutagenesis and cancer development. In this study, commercially available human placental DNA was exposed to 4-ABP (1.3 mM) in presence of sodium nitroprusside (SNP; 8 mM) at 37°C for 3 h. The 4-ABP + SNP-mediated structural changes in human DNA were studied by ultraviolet, circular dichroism and fluorescence spectroscopy, thermal melting profile, agarose gel electrophoresis, and nuclease S1 digestibility assay. Spectroscopical analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. This might be due to generation of single-stranded regions and destabilization of hydrogen bonds. Modification was also visualized in agarose gel electrophoresis. Furthermore, nuclease S1 digestibility confirmed the generation of single strand breaks. Rabbits challenged with 4-ABP-SNP-modified human DNA-induced high-titer immunogen-specific antibodies, which showed Cross-reaction with modified/unmodified DNA bases and ss-DNA in competitive inhibition assay. The immunogen specificity of induced antibodies against 4-ABP-SNP-modified human DNA was further confirmed in gel retardation assay. It may be concluded that induction of anti-modified DNA antibodies could be due to perturbation in the DNA structure and its subsequent recognition by immunoregulatory cells as a foreign molecule.
Pilomatrixoma of the eyelid is extremely rare in middle age
and rarely develops into a large tumor. A 45-year-old female
developed a painless, progressive swelling (3.0 cm × 2.0 cm)
of the left upper eyelid over a period of two years. Overlying
skin was normal in color and texture. A differential diagnosis of
dermoid, epidermoid cyst, chalazion and basal cell carcinoma
was made. An excisional biopsy was performed. A diagnosis
of pilomatrixoma was made on histopathological features
(dystrophic calcification of matrix with keratin and foreign
body granulomatous reaction, basaloid cells and shadow cells/
ghost cells). It also comprises ossification apart from the usual
calcification. This is a report of an unusually large ossifying
pilomatrixoma in left upper eyelid of a middle-aged woman. The
patient should be followed up at regular intervals to rule out any
recurrence or malignant transformation.
This study presents diagnostic histopathological features of a primary embryoid teratomatous neoplasm in the gall bladder of a 60-year-old woman, and also discusses its pathogenesis. Sections revealed immature and typical embryoid bodies and dispersed syncytial trophoblasts along with mature and immature neuroectodermal and mesodermal elements. The residual endothelial lining of the gall bladder showed in situ and proliferative changes characteristic of an endodermal tumour. Ultrasonographic and magnetic resonance imaging findings of the rest of the abdominal and pelvic organs appeared normal. Results show that the mature adult gall bladder is susceptible to primary neoplasms of a primitive nature ranging from immature embryoma and teratoma to neuroectodermal tumour. Such primitive neoplasms in adult organs where benign neuroectodermal elements are present may evolve from a constituent cell of an adult organ acquired during embryogenesis from a morula that differentiated into trophoblastic (outer) and embryoblastic (inner) cells, and existing dormant cells at rest until reactivation during oncogenesis.
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