Component spectra extraction from terahertz measurements of unknown mixtures.

The aim of this work is to extract component spectra from unknown mixtures in the terahertz region. To that end, a method, hard modeling factor analysis (HMFA), was applied to resolve terahertz spectral matrices collected from the unknown mixtures. This method does not require any expertise of the user and allows the consideration of nonlinear effects such as peak variations or peak shifts. It describes the spectra using a peak-based nonlinear mathematic model and builds the component spectra automatically by recombination of the resolved peaks through correlation analysis. Meanwhile, modifications on the method were made to take the features of terahertz spectra into account and to deal with the artificial baseline problem that troubles the extraction process of some terahertz spectra. In order to validate the proposed method, simulated wideband terahertz spectra of binary and ternary systems and experimental terahertz absorption spectra of amino acids mixtures were tested. In each test, not only the number of pure components could be correctly predicted but also the identified pure spectra had a good similarity with the true spectra. Moreover, the proposed method associated the molecular motions with the component extraction, making the identification process more physically meaningful and interpretable compared to other methods. The results indicate that the HMFA method with the modifications can be a practical tool for identifying component terahertz spectra in completely unknown mixtures. This work reports the solution to this kind of problem in the terahertz region for the first time, to the best of the authors' knowledge, and represents a significant advance toward exploring physical or chemical mechanisms of unknown complex systems by terahertz spectroscopy.

Metabolomics and its application in the mechanism analysis on diabetic bone metabolic abnormality.

OBJECTIVE: This study is aimed at analysing the endogenous metabolites profiling of patients with diabetic osteoporosis, so as to provide the reference for pathogenesis research of diabetic osteoporosis. PATIENTS AND METHODS: The 1H-NMR metabolomics technology, combined with pattern recognition analysis and SIMCA-P 12.0 statistical analysis, were employed to identify the metabolites differences between diabetic patients with disordered bone metabolism (research group) and healthy volunteers (normal group) in this study. RESULTS: Compared with normal group, the results show that in research group, the levels of O-acetyl glycoprotein, proline, 1-methyl histidine, tricarboxylic acid cycle (TCA cycle) product (citric acid and α-ketoglutaric acid) decline, while the levels of branched chain amino acids (leucine, isoleucine, valine), glucose, choline, creatine, inositol, glutamine, aspartic acid, alanine, glycine, and citrulline increase. CONCLUSIONS: There are disordered metabolic pathways and imbalanced bone synthetic materials and regulatory substances in diabetic patients with bone metabolic abnormality. These metabolic abnormalities could be the specific indicators in early diagnosis of diabetic osteoporosis.

Optical characterization of a Cd(0.85)Mg(0.15)Se mixed crystal.

We present an optical characterization of a Bridgman-grown wurtzite-type Cd(0.85)Mg(0.15)Se mixed crystal in the near-band-edge interband transitions using temperature-dependent contactless electroreflectance (CER) and photoreflectance (PR) in the temperature range 15-400 K. The interband excitonic transitions A and C originating from the band edge and spin-orbital splitting critical points of the sample, respectively, have been observed in the CER/PR spectra. The transition energies and broadening function of the excitonic features are determined via a lineshape fit to the CER/PR spectra. The parameters that describe the temperature dependence of the transition energies of excitons A and C, and the broadening function of exciton A, are evaluated and discussed.

Effect of different blood glucose intervention plans on elderly people with type 2 diabetes mellitus combined with dementia.

OBJECTIVE: We analyzed the effects of intensive and mitigatory blood glucose control strategy on elderly people with type 2 diabetes mellitus (T2DM) combined with Alzheimer disease (AD). PATIENTS AND METHODS: We enrolled 90 elderly patients with T2DM combined with AD to participate in this study. They were randomly divided into 3 groups: the control group, the strength group and the mitigation group with 30 cases in each group. In the control group, patients were only treated with diet and exercise while in the strength group patients were treated with oral hypoglycemic medications, subcutaneous insulin infusion or continuous infusion by micropump. Blood glucose level in the strength group patients was stabilized within 1 month (pre-meal ≤ 7.0 mmol/L, 2 hours post-meal glucose ≤ 12.0 mmol/L and glycosylated hemoglobin or HbA1c ≤ 7.0%). Personalized treatment programs were adopted for the mitigation group and the objective was to control the pre-meal blood glucose at ≤ 10.0 mmol/L (within 3 to 6 months) and also to control 2 hours post-meal blood glucose at ≤ 20.0 mmol/L (within 3 to 6 months). We compared the occurrence rate of diabetic complications, occurrence rate of new-onset dementia and progressive rate of dementia. RESULTS: Our results showed that target glucose rate in the mitigation group was significantly higher than that in the strength group. The occurrence rate of diabetic complications in the mitigation group was significantly lower than that observed in the other two groups. Occurrence rate of diabetic hyperosmolar coma was significantly higher in the control group, the occurrence rate of hypoglycemia was meaningfully lower in the strength group and the occurrence rate of new-onset target-organ injury was considerably higher in the mitigation group. The occurrence rate of new-onset dementia and progressive rate of dementia in mitigation group was significantly lower than those in other two groups. Comparison between the control group and the strength group did not reveal any statistical significance (p > 0.05). In the meantime, the survival time in mitigation group was significantly longer. CONCLUSIONS: Elderly patients with T2DM combined with AD may benefit more from the moderate control of blood glucose and a proper increase of the target value.

High glucose-induced apoptosis in human endothelial cells is mediated by sequential activations of c-Jun NH(2)-terminal kinase and caspase-3.

BACKGROUND: Diabetes mellitus causes multiple cardiovascular complications. High glucose can induce reactive oxygen species and apoptosis in endothelial cells. Little is known about the molecular mechanisms in high glucose-induced endothelial cell apoptosis. METHODS AND RESULTS: We elucidated the signaling pathway of high glucose-induced apoptosis in human umbilical vein endothelial cells (HUVECs). HUVECs were treated with media containing 5.5, 19, or 33 mmol/L of glucose in the presence or absence of an antioxidant, ascorbic acid. The level of intracellular H(2)O(2) was measured by flow cytometry. For detection of apoptosis, the cell death detection ELISA assay and the morphological Hoechst staining were used. High glucose was capable of inducing the activity of c-Jun NH(2)-terminal kinase (JNK) but not extracellular signal-regulated kinase 1/2 or p38 mitogen-activated protein kinase during the treatment periods, as evidenced by immunocomplex kinase assay. Moreover, we found that the interleukin 1beta-converting enzyme (ICE)/CED-3 family protease (caspase-3) became activated in high glucose-induced apoptosis. Caspase-3/CPP32-specific inhibitor, Ac-DEVD-CHO, could inhibit high glucose-induced apoptosis. Furthermore, we found that JNK1 specific antisense oligonucleotide could suppress caspase-3 activity but not affect H(2)O(2) generation and could block apoptosis induced by high glucose. Also, H(2)O(2) generation, JNK activity, caspase-3 activity, and the subsequent apoptosis induced by high glucose could be suppressed by ascorbic acid. CONCLUSIONS: The present study indicates that reactive oxygen species induced by high glucose may be involved in JNK activation, which in turn triggers the caspase-3 that facilitates the apoptosis in HUVECs.

Assessment of right ventricular anatomy and function by quantitative radionuclide ventriculography.

Determination of right ventricular ejection fraction and volumes from radionuclide studies is cumbersome and is subject to considerable methodologic error. Further, assessment of regional wall motion has only infrequently been approached in a systematic way. A system of right ventricular ejection fraction and volume measurements is described that utilizes the previously validated single plane geometric method applied to first pass radionuclide angiocardiograms. Five right ventricular chords were defined and used to assess regional wall motion; normal values were obtained from 14 patients who were without demonstrable cardiac disease. Among 23 patients with anterior myocardial infarction, the right ventricular ejection fraction was within 2 SD of normal in 16; however, 3 of these patients showed regional wall motion abnormalities in the right ventricle. Of 21 patients with inferior myocardial infarction, right ventricular ejection fraction was reduced in 15; of the 6 with normal values, 3 had regional wall motion abnormalities as demonstrated by the chord shortening method. Of 21 patients with dilated cardiomyopathy, right ventricular function was abnormal in 20; the presence of a wall motion abnormality in the conus segment separated these patients from patients with right ventricular dysfunction after recent myocardial infarction. Thus: 1) right ventricular ejection fraction, volumes and wall motion can be assessed by a simple, geometric technique; 2) analysis of chord shortening by this method provides information unavailable from global ejection fraction data alone; and 3) the clinical correlates of these data will require further investigation.

Significance of dobutamine-induced ST-segment evaluation and T-wave pseudonormalization in patients with Q-wave myocardial infarction: simultaneous evaluation by dobutamine stress echocardiography and thallium-201 SPECT.

The clinical significance of stress-induced ST-segment elevation and T-wave pseudonormalization in infarct-related leads is still controversial. Therefore, we conducted the present study to assess this issue using simultaneous dobutamine stress echocardiography (DSE) and thallium-201 single-photon emission computed tomography. A total of 119 patients with Q-wave myocardial infarction were enrolled in this study. There were 58 patients with (group I) and 61 patients without (group II) dobutamine-induced ST-T changes. Left ventricular ejection fraction was 43 +/- 13% in group I and 49 +/- 14% in group II (p <0.05). The baseline, low-, and peak-dose global wall motion scores were similar between these 2 groups (26.2 +/- 6.1 vs 26.2 +/- 6.3 [p = NS]; 24.1 +/- 5.3 vs 23.5 +/- 5.7 [p = NS]; 26.4 +/- 5.7 vs 26.7 +/- 6.1 [p = NS]). The sensitivity, specificity, and accuracy of these ST-T changes for detecting residual myocardial viability and ischemia documented by DSE in all patients were 50%, 53%, and 51% (for viability), and 47%, 48%, and 47% (for ischemia), respectively. The sensitivity, specificity, and accuracy of these ST-T changes for detecting a reversible perfusion defect documented by thallium-201 single-photon emission computed tomography were 51%, 54%, and 52%, respectively. In conclusion, dobutamine-induced ST elevation and/or T-wave pseudonormalization is associated with poor resting left ventricular function. These ST-T changes are not associated with residual myocardial ischemia and viability in the infarct area. Therefore, these electrocardiographic changes alone cannot be reliably considered as distinctive markers in formulating the therapeutic strategy of coronary intervention.

Comparison of simultaneous dobutamine echocardiography and thallium-201 stress-reinjection single-photon emission computed tomography in predicting improvement of chronic myocardial dysfunction after revascularization.

Previous studies have shown that ultrasonic integrated backscatter is valuable in characterizing stunned myocardium. Recent investigations have demonstrated that resting cardiac cycle-dependent variation of integrated backscatter closely paralleled the contractile reserve in patients with chronic left ventricular ischemic dysfunction. The purpose of this study was to validate whether ultrasonic tissue characterization (UTC) compared with dobutamine stress echocardiography (DSE) and thallium-201 stress-reinjection single-photon emission computed tomography (Tl-SPECT) could predict reversible myocardial dyssynergy in patients with chronic coronary artery disease. Forty-eight patients with stable coronary artery disease underwent UTC, DSE, and Tl-SPECT simultaneously before successful coronary revascularization and were followed up with echocardiograms at rest >3 months later. Among the 58 investigated segments, the weighted amplitude, a composite parameter derived from the integrated backscatter power curve, was larger for those groups with greater functional recovery (p <0.001). For the persistent akinetic segments, the weighted amplitudes were small with large deviations of the nadir ratios that represented the asynchrony between the intramural contractile events and the global systole. Using the cut-off value 2.0 of the weighted amplitude, the sensitivity and specificity for predicting functional improvement after revascularization were both 82.8% (kappa = 0.66) and comparable to the sensitivity and specificity of DSE and Tl-SPECT. UTC, delineating the myocardial physical state and intramural contraction, can be a novel approach in predicting functional improvement of chronic dyssynergy after revascularization.

Low-serum, high-density lipoprotein cholesterol concentration is an important coronary risk factor in Chinese patients with low serum levels of total cholesterol and triglyceride.

The significance of low-serum high-density lipoprotein concentrations (<35 mg/dl) with respect to coronary atherogenesis in Chinese patients with low levels of total serum cholesterol (<200 mg/dl) and triglycerides (<250 mg/dl) was assessed. Persons with such a lipid profile pattern were still at high risk, and high-density lipoprotein. like smoking, appeared to be the most predictive independent coronary risk factor.

Cardiovascular nuclear medicine: an overview.

Some of the available cardiovascular nuclear medicine methods are incompletely validated, and others are incompletely developed. They are, however, of very great potential in diagnostic cardiology, and in patient management. A new era of clinical research and acute care monitoring has been opened by serial, noninvasive, hemodynamic measurements of right ventricular as well as left ventricular function. Stress testing has become more specific, and should, with future developments, become more specific, and should, with future developments, become more sensitive, using radionuclide procedures. Serious quality control and validation questions concerning thallium stress testing must be addressed. Intracoronary injection of radiogases has great potential, although minimal present application. Emission computerized tomography will be an important research tool. Compartmental analysis modeling of first pass tracer injections has much to offer, but is not yet validated. Present growth rate of these procedures is very rapid. Fully developed, cardiovascular nuclear medicine may become the largest component of clinical nuclear medicine practice.

Assessment of the myocardial changes in heart transplant recipients without evident acute myocardial rejection by integrated backscatter: comparison with simultaneous dobutamine stress echocardiography and (201)thallium spect.

Cardiomyocyte hypertrophy and interstitial fibrin deposition develop in cardiac allografts and contribute to the functional changes of transplanted hearts. We hypothesized that integrated backscatter (IBS) can detect these myocardial changes. A total of 32 heart transplant recipients with either no or mild acute rejection (International Society of Heart and Lung Transplantation grade IA) were enrolled in this study. IBS data of myocardium were collected immediately before simultaneous dobutamine stress echocardiography (DSE) and (201)thallium imaging. Coronary angiography and endomyocardial biopsy were also performed. Coronary angiography showed diffuse narrowing in 1 patient who also had abnormal results of IBS, DSE, and thallium results. In the other 31 patients with patent coronary arteries, there were 3 patients (10%) with abnormal DSE results, 19 patients (61%) with abnormal IBS patterns, and 16 patients (52%) with reversible thallium perfusion defects. Of the patients, 44% had cardiomyocyte hypertrophy and 56% interstitial fibrin deposition. There were significant differences in the prevalence of (201)thallium perfusion defects and serum cyclosporine levels between patients with and without abnormal IBS patterns. Pathologic changes were also associated with abnormal IBS patterns (p = 0.01). However, there was no association between abnormal IBS and DSE results. By multiple logistic regression analysis, the abnormal IBS patterns were associated inversely with serum cyclosporine level (p = 0.028). In conclusion, abnormal IBS patterns are associated significantly with perfusion heterogeneity and pathologic changes in heart transplant recipients without evident acute myocardial rejection. There is no association between abnormal IBS patterns and dobutamine-induced dyssynergy in these patients. IBS provides a noninvasive approach for detection of myocardial changes in transplanted hearts without evident acute rejection.

Ultrasonic tissue characterization evaluates myocardial viability and ischemia in patients with coronary artery disease.

To evaluate whether or not ultrasonic tissue characterization (UTC) can detect jeopardized or salvageable myocardium in patients having chronic coronary artery disease, we studied 103 patients with sequential UTC, dobutamine stress echocardiography (DSE) and (201)thallium stress-reinjection single-photon emission computed tomography (T1-SPECT). This revealed that the weighted amplitude of the cyclic modulation of integrated backscatter was larger for the myocardium with less ischemia burden or greater viability (p<0.001). The segments with larger ischemia burden or the nonviable myocardium demonstrated the contrary result. Using the receiver-operating characteristic curve analyses to determine the cutoff value of weighted amplitude for various predictions, UTC can detect ischemia in normokinetic myocardium (kappa = 0.34 compared to DSE or T1-SPECT) and viability in dyssynergic myocardium (kappa = 0.57 compared to DSE and 0.45, to T1-SPECT). These observations show that UTC may prove useful in the identification and pathophysiological understanding of myocardial ischemia and viability.

Accuracy of biphasic response, sustained improvement and worsening during dobutamine echocardiography in predicting recovery of resting myocardial dysfunction after revascularization: comparison with thallium-201 SPECT.

To evaluate the accuracy of various types of wall motion response during dobutamine echocardiography (DE) in predicting functional recovery after revascularization, we studied 30 patients with stable coronary disease and left ventricular dysfunction by simultaneous DE and (201)Tl reinjection SPECT. Among 480 segments (16 segments/patient), 199 had abnormal wall motion at baseline and 167 were revascularized. The predictive value for recovery of function was 72% for a biphasic response, 61% for sustained improvement, 77% for worsening, and 27% for no change (p < 0.01 vs. each). Biphasic response had a sensitivity of 40% and specificity of 85%. Combining biphasic, sustained improvement and worsening responses, the sensitivity, specificity and accuracy were 76%, 65% and 71%, respectively. For (201)Tl SPECT, they were 90%, 65% and 78%, respectively. Thus, a biphasic response alone is of low sensitivity. Combination of biphasic, sustained improvement and worsening responses gives an accuracy rate comparable to that of (201)Tl reinjection SPECT in assessing functional recovery.

Gait analysis after ankle arthrodesis.

The purpose of this study was to employ a computerized motion analysis system to identify the effect of ankle arthrodesis on the three-dimensional kinematic behavior of the rear and fore foot during level walking. A three-segment rigid body model was used to describe the motion of the foot and ankle. The results demonstrated that sagittal plane motion of the hindfoot was significantly decreased in the foot of patients having had ankle arthrodesis compared to normal subjects. The kinematic data indicated a generalized stiffness of the hindfoot on the involved foot in the sagittal plane. Sagittal plane movement in the forefoot and transverse plane movements in the hindfoot and forefoot increased in patients compared to controls.

Inhomogeneity of myocardial perfusion in heart transplant recipients: evaluation with dobutamine thallium-201 SPECT.

Progressive heterogeneity of thallium-201 single photon emission computed tomography (Tl-201 SPECT) in heart transplant recipients has been documented in Caucasians. However, in Chinese heart transplant recipients, a lower incidence of transplant coronary artery disease (CAD) has been noted than in Western transplant recipients. In this study, we examine whether heterogeneity of Tl-201 SPECT exists in Chinese transplant recipients. Dobutamine Tl-201 SPECT was performed in 40 heart transplant recipients and the inhomogeneity scores were calculated. The difference between the scores of transplant recipients surviving less than 12 months and those of control subjects were not statistically significant. One year after transplantation, the inhomogeneity score increased progressively. The scores of transplant patients in the second and third years after transplant were similar to those of single-vessel CAD patients. Three years after transplant the scores were greatly increased. Thus, our data suggest that the progressive nature of graft vasculopathy also exists in Chinese heart transplant recipients. The progressive Tl-201 abnormalities may be one of the early signs of graft vasculopathy.

Persistent myocardial ischemia after termination of dipyridamole-induced ventricular tachycardia by intravenous aminophylline: scintigraphic demonstration.

Ventricular tachycardia is a rare complication of dipyridamole stress testing. We present a case in which dipyridamole induced symptomatic ventricular tachycardia. The patient, a 41-year-old man with a history of chest discomfort on exertion for 1 year, underwent dipyridamole thallium imaging. Sustained ventricular tachycardia occurred 1 minute and 40 seconds after completion of the dipyridamole infusion. Intravenous aminophylline (125 mg) was given immediately and the tachycardia was terminated. Two minutes later, thallium-201 was injected and subsequent myocardial imaging showed reversible perfusion defects in the inferior wall, septum, and apex. Coronary angiography revealed three-vessel disease. This case discloses that reversible perfusion defects can still be demonstrated on thallium scan in spite of injection of aminophylline, an antagonist of dipyridamole, before thallium administration.

Correlation between quantitative severity of stress thallium-201 myocardial perfusion defect and severity of coronary stenosis.

The correlation between the quantitative myocardial perfusion defect severity of stress 201Tl single-photon emission computed tomography and the severity of coronary stenosis was investigated in 28 patients with angina pectoris. Among the 28 patients, four had normal or nearly normal coronary angiograms, seven had one-vessel disease, six had two-vessel disease and 11 had three-vessel disease. Seven patients had prior myocardial infarctions and two had collateral flows to the diseased vessels. The quantitative 201Tl defect severity score was obtained by summing the standard deviations of each pixel in which the counts fell > 2.5 SD below the mean normal counts. The severity of coronary stenosis was expressed as the Gensini score. The quantitative 201Tl defect severity score correlated significantly with the Gensini score. In patients without prior myocardial infarction or collateral flow, a more significant correlation between the quantitative 201Tl defect severity score and the Gensini score was found. Quantitative analysis of stress 201Tl defect severity provides a useful, noninvasive assessment of the functional severity of coronary stenosis compared with coronary angiography.

Correlation between left ventricular systolic function and dipyridamole thallium SPECT redistribution patterns in coronary artery disease.

The dipyridamole thallium-201 single photon emission computed tomography (SPECT) and resting gated blood pool ventriculography were sequentially conducted in 31 consecutive patients with angiographically proven coronary artery disease. The functional significance of various thallium redistribution patterns was assessed. The patients with an entirely complete (CR) or partial (PR) redistribution pattern had a higher global left ventricular ejection fraction than those with combined PR and no redistribution (NR), while patients with an entirely CR pattern did not have a statistically better ejection fraction than those with PR. Furthermore, myocardial segments with normal perfusion (N) and those with CR or PR had a higher regional ejection fraction than those with NR in the infero-apical area and the septal area. The regional ejection fraction was statistically higher in patients with CR than in those with PR in the septal area and higher, though not statistically significant, in the infero-apical area. The functional difference between groups with N and CR was not significant. Thus, we conclude that the redistribution patterns of dipyridamole thallium SPECT are closely correlated with systole function. Myocardium, in the presence of redistribution, will have a better functional performance in coronary artery disease.