FTIR-ATR was used to study the effect of roasting conditions on the flavor of brewed coffee using Guatemala Antigua coffee beans. The 1800-1680 cm(-1) carbonyl region for vinyl esters/lactones, esters, aldehydes, ketones, and acids was found to provide a flavor-print of the brewed coffee. A study of light, medium, and dark roasts indicated that when the rate of heating to the onset of the first and second cracks was kept constant, the types of carbonyl compounds formed were similar, varying only in their concentration. This difference in concentration is apparently due to the additional heating of the coffee bean beyond the second crack. When the heating rate to the onset of the first and second crack was varied, both the types and concentration of the carbonyl compounds formed during roasting were affected. Thus, heating rates of green coffee beans to the onset of the first and second cracks are important determinants of the basic taste and aroma of brewed coffee.

A comparative study of Fourier transform infrared attenuated total reflection (FTIR-ATR) spectra of 32 scalp and pubic hair samples from individuals diagnosed with breast cancer and those who were negative for breast cancer showed increases in the beta-sheet/disorder structures (relative to alpha-helix structures) and C-H lipid content of hair from breast cancer patients. Thus, the presence of breast cancer appears to alter the hair growth process, resulting in changes in the composition and conformation of cell membrane and matrix materials of hair fiber. These appear to be consistent with the changes observed in X-ray diffraction patterns for hair from breast cancer patients. A blind study of 12 additional hair samples using these FTIR-ATR spectral differences as markers correctly identified all four hair samples from cancer patients (100%). Two of these samples were from breast cancer patients. Of the remaining two samples analyzing positive for cancer, one was from a prostate cancer patient and one from a lung cancer patient. Thus, it appears that the mechanism that alters hair fiber synthesis in the three types of cancer may be similar. The blind study incorrectly identified as positive for cancer three hair samples from two apparently healthy individuals and one patient considered cured from prostate cancer.

FTIR-ATR analysis has shown that the 4-step process for preclotting polyester vascular grafts results in a uniform and reproducible fibrin coating of the polyester fibers. Western blot analyses have shown that FN and VEGF are also present in this fibrin coating. FTIR-ATR analyses of explanted grafts indicate that, while the in vivo healing of these preclotted polyester grafts proceed through the inflammation, proliferation, and remodeling phases of normal wound healing, these phases are modified. Because the fibrin coating provides a nonporous barrier between peri-graft tissue and the flowing blood, these molecular changes are controlled by the interactions of blood-borne constituents with the lumenal surface of the preclotted graft. Also, a well prepared preclotted polyester graft shows a minimal inflammatory response. After implantation, the fibrin preclot is more than 90% gone by the fifth day. However, the proliferation phase, involving synthesis of new protein and polysaccharide materials to replace the fibrin, appears to have begun by the third day. Detection of collagen I in the 5-day explants suggests that the overlapping remodeling phase of healing has begun. Protein and saccharide materials continue to be synthesized and remodeled, and, by the tenth day, collagen IV is detected. By 14-days post-implantation, there is an increase in collagen IV and cellular membrane lipids. Because collagen IV is an indicator of the presence of endothelial cells, some of these cellular membranes must be of endothelial origin. Thus, it appears that FTIR-ATR can be a useful tool in the study of vascular healing.

Attenuated total reflection Fourier transform infrared (ATR/FT-IR) spectra of wet horse hair α-keratin indicate that the conformation of extended α-keratin is affected by the water temperature. Extension of the wet horse hair in 21 °C water gives rise to parallel β-sheet structures, thus suggesting that the original α-helical structure is also parallel. In contrast, extension of the wet horse hair α-keratin in 95 °C water gives rise to anti-parallel β-sheet structures (consistent with reported literature where X-ray diffraction was used), suggesting that disulfide interchange and/or increased chain mobility at elevated temperatures plays a role in altering the secondary structure.

A bigraft, composed of a 30-microm internodal distance expanded polytetrafluoroethylene (ePTFE) arterial graft segment and a preclotted polyethylene terephthalate arterial graft segment, was used to study the healing process of two different materials in the same dog. Healing was followed by FTIR-ATR spectroscopy and correlated with ELISA analyses of selected growth factors and matrix proteins. The FTIR analyses of the ePTFE explants from 1 and 3 h; 3, 5, 7, 10, and 14 days; and 4 and 8 weeks showed that the ePTFE grafts did not heal (endothelialize), but appeared to remain in overlapping inflammation and proliferation stages of wound healing. Although FN was found in the fibrin layer coating the luminal surface of the ePTFE, VEGF was not present. The inability of VEGF to complex with FN may be the result of FN binding sites being blocked or hidden by the conformation of the fibrin clot that forms on ePTFE. Also, TGF-beta was not present beyond the initial clot formation at 3 h postimplantation. The absence of these two growth factors may be an important factor in the lack of healing of 30-microm ePTFE grafts, because both were found to be present during the early stages of healing for the preclotted polyester grafts that did endothelialize.

FTIR analysis of sequential biopsy samples of the primary and replacement segments obtained from 70 to 80-cm long carotid-femoral bypass grafts implanted bilaterally in the dog indicate that the healing pattern is similar over the entire length of these grafts. Preliminary analysis of the spectra also indicates that the major developments in the formation of the biological layer appear to occur during the first 4 weeks after implantation. Collagen IV could be detected by both FTIR and antibody staining in the 8-week samples. Thus, this study supports the application of FTIR attenuated total reflectance to determine the components of the biological tissue that forms on an implanted vascular graft surface.

A polyester (PET) reinforced fibrin-FN-VEGF-TGFbeta vascular graft, formed by a four-step preclotting technique of a porous PET arterial graft, shows the overlapping inflammation, proliferation, and remodeling steps of normal wound healing when implanted in the descending thoracic aorta (DTA) position in the dog, forming a surface layer of endothelial cells. While the DTA grafts readily healed (i.e., endothelialized), similar grafts implanted in the carotid-femoral artery position did not fully heal. Since the initial phases of healing were shown to be dependent upon the transport of blood-borne constituents to the graft surface, the extent of healing appears to be dependent on the fluid dynamics present in the artery-graft-artery construct. The length of the noncompliant graft, the construction of the anastomoses, bends in the construct, graft diameter, and graft compliance can affect the fluid dynamics in the implant, and thus the healing of the graft. This has clinical relevance for the testing and development of new vascular graft materials.

FTIR analysis of sequential biopsy samples of the primary and replacement segments obtained from 70 to 80-cm long carotid-femoral bypass grafts implanted bilaterally in the dog indicate that the healing pattern is similar over the entire length of these grafts. Preliminary analysis of the spectra also indicates that the major developments in the formation of the biological layer appear to occur during the first 4 weeks after implantation. Collagen IV could be detected by both FTIR and antibody staining in the 8-week samples. Thus, this study supports the application of FTIR attenuated total reflectance to determine the components of the biological tissue that forms on an implanted vascular graft surface.