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    Assessment of spatially offset Raman spectroscopy to detect differences in bone matrix quality
    (Pergamon-Elsevier Science Ltd, 2023) Gautam, Rekha; Ahmed, Rafay; Haugen, Ezekiel; Unal, Mustafa; Fitzgerald, Sean; Uppuganti, Sasidhar
    Since spatially offset Raman spectroscopy (SORS) can acquire biochemical measurements of tissue quality through light scattering materials, we investigated the feasibility of this technique to acquire Raman bands related to the fracture resistance of bone. Designed to maximize signals at different offsets, a SORS probe was used to acquire spectra from cadaveric bone with and without skin-like tissue phantoms attenuating the light. Autoclaving the lateral side of femur mid-shafts from 5 female and 5 male donors at 100 degrees C and again at 120 degrees C reduced the yield stress of cortical beams subjected to three-point bending. It did not affect the volumetric bone mineral density or porosity. Without tissue phantoms, autoclaving affected more Raman characteristics of the organic matrix when determined by peak intensity ratios, but fewer matrix properties depended on the three offsets (5 mm, 6 mm, and 7 mm) when determined by band area ratios. The cut-off in the thickness of the tissue phantom layers was-4 mm for most properties, irrespective of offset. Matching trends when spectra were acquired without phantom layers between bone and the probe, & nu;1PO43 ? /Amide III and & nu;1PO43%(proline + OHproline) were higher and lower in the non-treated bone than in the autoclaved bone, respectively, when the thickness of tissue phantom layers was 4 mm. The layers, however, caused a loss of sensitivity to autoclaving related changes in & nu;3CO3/& nu;1PO43 ? and crystallinity. Without advanced post-processing of Raman spectra, SORS acquisition through turbid layers can detect changes in Raman properties of bone that accompany a loss in bone strength.
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    Öğe
    Current multidisciplinary approach to diabetes mellitus occurrence mechanism
    (Nobel Tıp Bookstores, 30/09/2023) Rağbetli, Murat Çetin; Kaya, Aysenur; Keskin, Seda; Kıran, Tugba Raika; Karabulut Bay, Aysun; Unal, Mustafa; Uguz, A. Cihangir; Kocaman, Süheyla; Dasdelen, Dervis; Koksoy, Hale; Kocabas, Rahim; Ecesoy, Volkan; Arıcı, Hasan; Osmanoglu, Omer Usame; Irgat İncedal, Serap; Gumus, Hale Hatice; Alp, Harun; Rağbetli, Murat Çetin; Koksoy, Hale
    This book aims to provide a current and comprehensive perspective on Diabetes mellitus, a valuable subject in the field of basic sciences. Diabetes mellitus is a chronic disease that affects millions of people worldwide and has become an increasingly serious health problem. This book examines the underlying mechanisms and causes of diabetes using the disciplines of basic sciences. The content of the book begins with fundamental information such as the definition, classification, histopathological mechanisms, and epidemiology of diabetes. It also includes interesting sections on current technologies and the use of artificial intelligence in the field of diabetes. Additionally, the book extensively discusses how genetic predisposition, environmental factors, and lifestyle choices affect the risk of diabetes. This comprehensive evaluation of diabetes from the perspective of basic sciences provides important insights into the development and progression of the disease.
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    Long-Duration Type 1 Diabetes Alters Bone Matrix Composition but Does Not Influence Microarchitecture or Mechanical Behavior in Femoral Trabecular Bone in Older Adults
    (Oxford Univ Press, 2024) Emerzian, Shannon R.; Behzad, Jackson Hanlon Ramina; Unal, Mustafa; Brooks, Daniel; Wu, I-Hsien; Jangolla, Surya; Yu, Marc Gregory
    [Abstract Not Available]
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    Long-duration type 1 diabetes is associated with deficient cortical bone mechanical behavior and altered matrix composition in human femoral bone
    (Oxford Univ Press, 2024) Emerzian, Shannon R.; Unal, Mustafa; Brooks, Daniel J.; Wu, I-Hsien; Gauthier, John
    Type 1 diabetes (T1D) is associated with an increased risk of hip fracture beyond what can be explained by reduced bone mineral density, possibly due to changes in bone material from accumulation of advanced glycation end-products (AGEs) and altered matrix composition, though data from human cortical bone in T1D are limited. The objective of this study was to evaluate cortical bone material behavior in T1D by examining specimens from cadaveric femora from older adults with long-duration T1D (>= 50 yr; n = 20) and age- and sex-matched nondiabetic controls (n = 14). Cortical bone was assessed by mechanical testing (4-point bending, cyclic reference point indentation, impact microindentation), AGE quantification [total fluorescent AGEs, pentosidine, carboxymethyl lysine (CML)], and matrix composition via Raman spectroscopy. Cortical bone from older adults with T1D had diminished postyield toughness to fracture (-30%, p = .036), elevated levels of AGEs (pentosidine, +17%, p = .039), lower mineral crystallinity (-1.4%, p = .010), greater proline hydroxylation (+1.9%, p = .009), and reduced glycosaminoglycan (GAG) content (-1.3%, p < .03) compared to nondiabetics. In multiple regression models to predict cortical bone toughness, cortical tissue mineral density, CML, and Raman spectroscopic measures of enzymatic collagen crosslinks and GAG content remained highly significant predictors of toughness, while diabetic status was no longer significant (adjusted R-2 > 0.60, p < .001). Thus, the impairment of cortical bone to absorb energy following long-duration T1D is well explained by AGE accumulation and modifications to the bone matrix. These results provide novel insight into the pathogenesis of skeletal fragility in individuals with T1D.
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    Sensitivity of the amide I band to matrix manipulation in bone: a Raman micro-spectroscopy and spatially offset Raman spectroscopy study
    (Royal Soc Chemistry, 2023) Ahmed, Rafay; Unal, Mustafa; Gautam, Rekha; Uppuganti, Sasidhar; Derasari, Shrey; Mahadevan-Jansen, Anita
    The fracture resistance of bone arises from the hierarchical arrangement of minerals, collagen fibrils (i.e., cross-linked triple helices of & alpha;1 and & alpha;2 collagen I chains), non-collagenous proteins, and water. Raman spectroscopy (RS) is not only sensitive to the relative fractions of these constituents, but also to the secondary structure of bone proteins. To assess the ability of RS to detect differences in the protein structure, we quantified the effect of sequentially autoclaving (AC) human cortical bone at 100 & DEG;C (& SIM;34.47 kPa) and then at 120 & DEG;C (& SIM;117.21 kPa) on the amide I band using a commercial Raman micro-spectroscopy (& mu;RS) instrument and custom spatially offset RS (SORS) instrument in which rings of collection fiber optics are offset from the central excitation fiber optics within a hand-held, cylindrical probe. Being clinically viable, measurements by SORS involved collecting Raman spectra of cadaveric femur mid-shafts (5 male & 5 female donors) through layers of a tissue mimic. Otherwise, & mu;RS and SORS measurements were acquired directly from each bone. AC-related changes in the helical status of collagen I were assessed using amide I sub-peak ratios (intensity, I, at & SIM;1670 cm(-1) relative to intensities at & SIM;1610 cm(-1) and & SIM;1640 cm(-1)). The autoclaving manipulation significantly decreased the selected amide I sub-peak ratios as well as shifted peaks at & SIM;1605 cm(-1) (& mu;RS), & SIM;1636 cm(-1) (SORS) and & SIM;1667 cm(-1) in both & mu;RS and SORS. Compared to & mu;RS, SORS detected more significant differences in the amide I sub-peak ratios when the fiber optic probe was directly applied to bone. SORS also detected AC-related decreases in I-1670/I-1610 and I-1670/I-1640 when spectra were acquired through layers of the tissue mimic with a thickness & LE;2 mm by the 7 mm offset ring, but not with the 5 mm or 6 mm offset ring. Overall, the SORS instrument was more sensitive than the conventional & mu;RS instrument to pressure- and temperature-related changes in the organic matrix that affect the fracture resistance of bone, but SORS analysis of the amide I band is limited to an overlying thickness layer of 2 mm.