Raman spectroscopic Characterization of Anomalous Intravascular Fibrous Casts: Evidence for Stage-Dependent β-sheet Enriched Protein Maturation

White to pale, rubbery intravascular fibrous casts recovered during routine embalming were analyzed using Raman micro spectroscopy (633 nm and 785 nm excitation), the Kjeldahl method for total crude protein estimation, and ion exchange chromatography for amino acid profiling. Raman spectra from both specimens exhibited strong protein signatures, with notable differences in the Amide I/Amide III intensity ratio and the presence of a 1620 cm⁻¹ Amide I sub band. Expert Raman analysis distinguishes a native like, predominantly α helical configuration in one specimen from a more β sheet enriched, aggregation advanced state in the other (S1 vs S2). Additional spectral markers in the β sheet enriched specimen, including sharper aromatic ring breathing modes and phosphorylation associated bands, suggest a more ordered and stabilized secondary structure arrangement. Kjeldahl analysis measured total crude protein at 7.72 m/m% for the analyzed sample, and ion exchange amino acid profiling returned the composition listed in Results. The combined spectroscopic and compositional data indicate that these casts represent atypical protein aggregates exhibiting heterogeneity consistent with stage dependent β sheet enrichment, distinct from conventional postmortem thrombi. Although donor histories were unavailable, the distinct physical and spectroscopic features of these casts may aid in their recognition during embalming and postmortem examination.