Glycemic excursions could be monitored precisely in the subcutaneous tissue by this microdialysis sampling method with a needle-type glucose sensor in ambulatory diabetic patients.

Whether Fourier transform infra-red spectroscopy with an attenuated total reflection prism could be applied for noninvasive glucose measurement through oral mucosa was evaluated. As a result, the same absorbance peak at 1033 cm-1 as in glucose aqueous solution was found in the absorbance spectra through mucous membrane. However, these glucose specific peaks were interfered with by the baseline drifts owing to prism attachment and the background spectra from body constituents other than glucose. Therefore, to eliminate these interferences, the calibration curve between the second derivatives of the absorbance peak at 1033 cm-1 and those at 2920 cm-1 was calculated (r = 0.910). By using this calibration curve, the spectral changes due to prism attachment were first eliminated. Secondly, by obtaining the second derivative of the difference between the postprandial absorbance peak and the fasting sample as a characteristic of an individual, high correlations between the corrected second derivatives of absorbance spectra through the mucous membrane of the lip at 1033 cm-1 and the increases in blood glucose concentrations above fasting levels were observed (r = 0.910). In conclusion, it was suggested that Fourier transform infra-red spectroscopy could be useful for noninvasive monitoring of glucose through oral mucosa.

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Persistently high cardiac troponin T (cTnT) levels reflect myocardial damage in heart failure (HF). The presence and extent of myocardial fibrosis assessed by cardiac magnetic resonance (CMR) and high levels of cTnT predict poor prognosis in various cardiomyopathies. However, the association between myocardial fibrosis and transcardiac cTnT release has not been evaluated. This study investigated the correlation between myocardial fibrosis and transcardiac cTnT release from nonischemic failing myocardium. Serum cTnT levels were measured in aortic root (Ao) and coronary sinus (CS) using highly sensitive assay (detection limit >5 ng/L) in 74 nonischemic patients with HF who underwent CMR. Transcardiac cTnT release (ΔcTnT [CS-Ao]) represented the difference between CS and Ao-cTnT levels. Myocardial fibrosis was quantified by late gadolinium enhancement (LGE) volume and %LGE on CMR. cTnT was detectable in 65 patients (88%), and ΔcTnT (CS-Ao) levels were available (ΔcTnT [CS-Ao] >0 ng/L) in 60 patients (81%). LGE was observed in 42 patients (57%), and ΔcTnT (CS-Ao) levels were available in 41 LGE-positive patients (98%). In patients with available cTnT release, ΔcTnT (CS-Ao) levels were significantly higher in LGE-positive patients than those in LGE-negative patients (4.3 [2.2-5.5] vs 1.5 [0.9-2.6] ng/L; p = 0.001). Log (ΔcTnT [CS-Ao]) levels were correlated with LGE volume (r = 0.460, p = 0.003) and %LGE (r = 0.356, p = 0.03). In conclusion, the amount of transcardiac cTnT release was higher in LGE-positive patients than LGE-negative patients and correlated with the extent of LGE in nonischemic patients with HF. These results suggested that ongoing myocardial damage correlates with the presence and extent of myocardial fibrosis.

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