Fourier-transform infrared spectroscopic study of characteristic molecular structure in cancer cells of esophagus: an exploratory study.

OBJECTIVE: To investigate the structural changes at the molecular level and to assess the usefulness of Fourier-transform infrared (FTIR) spectroscopy in the diagnosis of esophageal cancer. METHODS: A pilot study was established of 10 consecutive patients with adenocarcinoma of the esophagus. Tissue samples from the diseased and normal sites of the resected specimens were analyzed and compared using FTIR spectroscopy and histopathology. RESULTS: Specific changes were observed in the FTIR spectral features of esophageal cancer and thus spectral criteria were established for the detection of malignancy in esophagus tissues by FTIR spectroscopy. The spectral changes in cancer were the results of characteristic structural alterations at the molecular level in the esophageal cancer specimens. These alternations included an increase in the nuclei-to-cytoplasm ratio, an increase in the relative amount of DNA while a decrease in the relative amount of RNA, an enhancement in the phosphorylation of proteins, a decrease in the glycogen level, a loss of hydrogen bonding of the COH groups in the amino acid residues of proteins, a tighter intermolecular packing and a stronger intermolecular interaction among the DNA molecules, an increase in the distribution of protein segments with the conformation of beta-sheet and unordered turns and a tighter packing of the alpha-helical segments in overall tissue proteins, a decrease in the overall CH(3)-to-CH(2) ratio and an accumulation of triglycerides. CONCLUSIONS: FTIR is an automated method that has shown promise in differentiating cancer in the esophagus and may play a role in surveillance programs in premalignant conditions.

Sperm capacitation induces an increase in lipid rafts having zona pellucida binding ability and containing sulfogalactosylglycerolipid.

Sperm gain full ability to bind to the zona(e) pellucida(e) (ZP) during capacitation. Since lipid rafts are implicated in cell adhesion, we determined whether capacitated sperm lipid rafts had affinity for the ZP. We demonstrated that lipid rafts, isolated as low-density detergent resistant membranes (DRMs), from capacitated pig sperm had ability to bind to homologous ZP. This binding was dependent on pig ZPB glycoprotein, a major participant in sperm binding. Capacitated sperm DRMs were also enriched in the male germ cell specific sulfogalactosylglycerolipid (SGG), which contributed to DRMs-ZP binding. Furthermore, SGG may participate in the formation of sperm DRMs due to its interaction with cholesterol, an integral component of lipid rafts, as shown by infrared spectroscopic studies. Since sperm capacitation is associated with cholesterol efflux from the sperm membrane, we questioned whether the formation of DRMs was compromised in capacitated sperm. Our studies indeed revealed that capacitation induced increased levels of sperm DRMs, with an enhanced ZP affinity. These results corroborated the implication of lipid rafts and SGG in cell adhesion and strongly suggested that the enhanced ZP binding ability of capacitated sperm may be attributed to increased levels and a greater ZP affinity of lipid rafts in the sperm plasma membrane.

Detailed account of confounding factors in interpretation of FTIR spectra of exfoliated cervical cells.

The confounding variables that can potentially lead to a misinterpretation of FTIR spectroscopy of exfoliated cervical cells is described. A detailed account of the spectral effects of the following variables in FTIR spectroscopic screening of exfoliated cervical cells is presented: polymorphs; Cell degradation; and impurities such as endocervical columnar cells, metaplastic cells, cervical mucus, red cells, and debris. The interpretation of the spectra of exfoliated cervical cells must be done with subtraction analysis, which includes these factors. This is essential to prevent unacceptable false-positive rates. The above techniques are subsequently applied to two clinic populations: a dysplasia clinic in follow-up patients with negative cytology and two general gynecology clinics with patients with negative cytology. In the dysplasia clinic group 250 sequential patients with negative smears were tested. Thirty had false-positive smears as defined by the IR spectroscopy using the above methodology. Twenty of those patients subsequently had one follow-up and six had a positive abnormal smear. In the community clinic group 656 sequential patients were examined who had negative smears, of which 27 had false-positive FTIR spectra.