Determination of phthalic acid esters in Chinese white spirit using dispersive liquid-liquid microextraction coupled with sweeping ß-cyclodextrin-modified micellar electrokinetic chromatography.

A simple method that consumes low organic solvent is proposed for the analysis of phthalic acid esters in Chinese white spirit using dispersive liquid-liquid microextraction coupled with sweeping-micellar electrokinetic chromatography. Tetrachloromethane and white-spirit-containing ethanol were used as the extraction and dispersing solvents, respectively. The electrophoresis separation buffer was composed of 5 mM ß-cyclodextrin, 50 mM sodium dodecyl sulfate and 25 mM borate buffer (pH 9.2) with 9% acetonitrile, enabling the baseline resolution of the analytes within 13 min. Under the optimum conditions, satisfactory linearities (5-1000 ng/mL, r ≥ 0.9909), good reproducibility (RSD ≤ 6.7% for peak area, and RSD ≤ 2.8% for migration time), low detection limits (0.4-0.8 ng/mL) and acceptable recovery rates (89.6-105.7%) were obtained. The proposed method was successfully applied to 22 Chinese white spirits, and the content of dibutyl phthalate in 55% of the samples exceeded the Specific Migration Limit of 0.3 mg/kg established by the domestic and international regulations.

Arytenoid adduction for correcting vocal fold asymmetry: high-speed imaging.

OBJECTIVES: We hypothesized that high-speed digital imaging provides a quantitative method to evaluate the effect of arytenoid adduction for the correction of asymmetric and irregular vocal fold vibration in unilateral vocal fold paralysis. METHODS: Six subjects with unilateral vocal fold paralysis participated in the study (4 male, 2 female; mean [-SD] age, 52.5 +/- 21.3 years). Videokymographic and laryngotopographic methods for image analysis were performed for high-speed recordings of vocal fold vibration for visualizing the glottal vibratory patterns, and for quantifying the frequency of vibration of each vocal fold, respectively. Comparisons of the paralyzed and the normal vocal folds were made before and after arytenoid adduction. RESULTS: Analysis of the laryngotopographs revealed 2 distinct frequencies of vibration for the paralyzed and the contralateral vocal folds for all subjects before surgery. After arytenoid adduction, the vibration frequencies became identical or nearly identical in all subjects. CONCLUSIONS: Asymmetric vibration in vocal fold paralysis was exemplified by differences in vibration frequency between the vocal folds. The present data showed that after arytenoid adduction the vibration frequencies and the vibratory patterns of the contralateral vocal folds approached symmetry. This surgical procedure could improve the functional symmetry of the larynx for phonation.

Advances in laryngeal imaging.

Imaging and image analysis became an important issue in laryngeal diagnostics. Various techniques, such as videostroboscopy, videokymography, digital kymography, or ultrasonography are available and are used in research and clinical practice. This paper reviews recent advances in imaging for laryngeal diagnostics.

Clinical Practicability of a Newly Developed Real-time Digital Kymographic System.

BACKGROUND: A digital kymogram shows real images of vocal fold vibration. However, DKG is difficult to use in clinical practice because the recorded image cannot be seen instantaneously after examination, as considerable encoding time is required to visualize a digital kymogram. In addition, frame-by frame analysis should be implemented to evaluate high-speed videoendoscopy data, but is time- and labor-intensive. PURPOSE: The purpose of the study was to validate the clinical practicability of a real-time multislice digital kymographic system developed by the authors. We analyzed the promptness and accuracy of the examination before and after intracordal injections in patients with unilateral vocal fold paralysis. METHODS: To assess the clinical applicability of this system, six patients with unilateral vocal fold paralysis were selected. Real-time DKG was performed before and immediately after intracordal injection. We observed changes in the digital kymogram after the intracordal injection. RESULTS: Using this system, 10 scanning lines and up to five vertical pixel row could be obtained in real time, and the maximum acquisition time for the DKG image was 10 seconds. A digital kymogram of the patients could be instantaneously acquired, and whether the intracordal injection was appropriate or not. CONCLUSION: This article is the first validation study after the development of the real-time multislice digital kymographic system. Our system may be a promising tool in clinical practice for immediate assessment of the vibratory patterns of the vocal cords. More research is necessary for further clinical validation.

Three registers in an untrained female singer analyzed by videokymography, strobolaryngoscopy and sound spectrography.

There has been a lack of objective data on the singing voice registers, particularly on the so called "whistle" register, occurring in the top part of the female pitch range, which is accessible only to some singers. This study offers unique strobolaryngoscopic and high-speed (7812.5 imagess) videokymographic data on the vocal fold behavior of an untrained female singer capable of producing three distinct voice qualities, i.e., the chest, head and whistle registers. The sound was documented spectrographically. The transition from chest to head register, accompanied by pitch jumps, occurred around tones B4-C#5 (500-550 Hz) and was found to be associated with a slight decrease in arytenoids adduction, resulting in decrease of the closed quotient. The register shifts from head to whistle, also accompanied by pitch jumps, occurred around tones E5-B5 (670-1000 Hz) without any noticeable changes in arytenoids adduction. Some evidence was found for the vocal tract influence on this transition. The mechanism of the vocal fold vibration in whistle register was found principally similar to that at lower registers: vibrations along the whole glottal length and vertical phase differences (indicated by sharp lateral peaks in videokymography) were seen on the vocal folds up to the highest tone G6 (1590 Hz).

High-speed digital imaging and electroglottography of tracheoesophageal phonation by Amatsu's method.

BACKGROUND: Our previous findings have indicated that the thyropharyngeal muscles form a retropharyngeal prominence during alaryngeal phonation via the TE fistula. This prominence forms a so-called 'neoglottis', which is thought to function as the vibratory source. To better understand the mechanism of TE phonation, we analyzed the vibration of the neoglottis using electroglottography (EGG) and a high-speed digital imaging system. PATIENTS AND METHODS: Two volunteers who use TE phonation for their daily speech communication were subjected to this study. The vibrations of the neoglottis were recorded simultaneously as EGG and high-speed imaging with acoustic signals. RESULTS: The vibrations of the neoglottis, recorded by means of high-speed digital imaging, were exactly synchronized with the waveforms of the acoustic signals and EGG. CONCLUSIONS: These results further confirm the neoglottis as the source of vibration during tracheoesophageal (TE) phonation.

A comparison of different methods to measure the EGG contact quotient.

The results from six published electroglottographic (EGG-based) methods for calculating the EGG contact quotient (CQEGG) were compared to closed quotients derived from simultaneous videokymographic imaging (CQKYM). Two trained male singers phonated in falsetto and in chest register, with two degrees of adduction in both registers. The maximum difference between methods in the CQEGG was 0.3 (out of 1.0). The CQEGG was generally lower than the CQKYM. Within subjects, the CQEGG co-varied with the CQkym, but with changing offsets depending on method. The CQEGG cannot be calculated for falsetto phonation with little adduction, since there is no complete glottal closure. Basic criterion-level methods with thresholds of 0.2 or 0.25 gave the best match to the CQKYM data. The results suggest that contacting and de-contacting in the EGG might not refer to the same physical events as do the beginning and cessation of airflow.

Measurement of clavicular length and shortening after a midshaft clavicular fracture: Spatial digitization versus planar roentgen photogrammetry.

PURPOSE: Clavicular shortening after fracture is deemed prognostic for clinical outcome and is therefore generally assessed on radiographs. It is used for clinical decision making regarding operative or non-operative treatment in the first 2weeks after trauma, although the reliability and accuracy of the measurements are unclear. This study aimed to assess the reliability of roentgen photogrammetry (2D) of clavicular length and shortening, and to compare these with 3D-spatial digitization measurements, obtained with an electromagnetic recording system (Flock of Birds). PATIENTS AND METHODS: Thirty-two participants with a consolidated non-operatively treated two or multi-fragmented dislocated midshaft clavicular fracture were analysed. Two observers measured clavicular lengths and absolute and proportional clavicular shortening on radiographs taken before and after fracture consolidation. The clavicular lengths were also measured with spatial digitization. Inter-observer agreement on the radiographic measurements was assessed using the Intraclass Correlation Coefficient (ICC). Agreement between the radiographic and spatial digitization measurements was assessed using a Bland-Altman plot. RESULTS: The inter-observer agreement on clavicular length, and absolute and proportional shortening on trauma radiographs was almost perfect (ICC>0.90), but moderate for absolute shortening after consolidation (ICC=0.45). The Bland-Altman plot compared measurements of length on AP panorama radiographs with spatial digitization and showed that planar roentgen photogrammetry resulted in up to 37mm longer and 34mm shorter measurements than spatial digitization. CONCLUSION: Measurements of clavicular length on radiographs are highly reliable between observers, but may not reflect the actual length and shortening of the clavicle when compared to length measurements with spatial digitization. We recommend to use proportional shortening when measuring clavicular length or shortening on radiographs for clinical decision making.

Accuracy of cardiokymography during exercise testing: results of a multicenter study.

To determine the diagnostic accuracy of cardiokymography, recorded 2 to 3 minutes after exercise, 617 patients undergoing cardiac catheterization were evaluated from 12 participating centers using a standardized protocol. Adequate cardiokymographic tracings, which were obtained in 82% of patients, were dependent on the skill of the operator and on certain patient characteristics. Of the 327 patients without prior myocardial infarction who had technically adequate cardiokymographic and electrocardiographic tracings, 166 (51%) had coronary disease. Both the sensitivity and specificity of cardiokymography (71 and 88%, respectively) were significantly greater than the values for the exercise electrocardiogram (61 and 76%, respectively, both p less than 0.01). Coronary artery disease and multivessel disease were present in 98 and 68%, respectively, of the 70 patients with concordantly positive cardiokymographic and electrocardiographic results, and in 15 and 5%, respectively, of the 132 patients with concordantly negative test results (p less than 0.001). Cardiokymography was most helpful in those patients in whom the posttest probability of coronary disease was between 21 and 72% after exercise electrocardiography. In these patients a concordantly positive cardiokymographic result increased the probability of coronary disease to between 67 and 100%, whereas a negative response decreased it to between 12 and 15%. In the subgroup of 102 patients undergoing concomitant exercise thallium testing, the sensitivity and specificity for the thallium scintigraphy (81 and 80%, respectively) were similar to the values for cardiokymography (72 and 84%, respectively; differences not significant). Thus, cardiokymography performed during exercise testing improves the diagnostic accuracy of the electrocardiographic response and provides an additional and cost-effective indicator of myocardial ischemia.

What have we learned about laryngeal physiology from high-speed digital videoendoscopy?

PURPOSE OF REVIEW: The purpose of this review is to describe recent developments in high-speed videoendoscopy. The applications of this technique are highlighted and important findings regarding vocal fold physiology and voice pathology are discussed. RECENT FINDINGS: The number of applications for digital high-speed imaging has increased during recent years because of the development of camera image sensor systems with increased image resolution of video and television quality. Other improvements are related to computer processing speed and storage capacity and the development of automatic algorithms for quantification and measurements both in time and room dimensions. This is enhanced by combining high-speed videoendoscopy with laser-based measurement systems, acoustic analyses or other glottographic methods, such as flow glottography or electroglottography. High-speed videoendoscopy is currently used in studies of voice mechanisms of phonation (e.g., the voice source can be examined with a high sampling rate, from 1000 to over 8000 frames per second), and in phonation onset or offset. High-speed imaging is also useful in linguistic studies and in the examination of different artistic singing styles, such as extremely high-pitched singing, throat singing, or different pop and rock styles. High-speed videoendoscopy is also used in the examination of patients with voice disorders, particularly with irregular vocal fold vibrations, ventricular phonation, or the phonation of individuals who have had a laryngectomy. SUMMARY: Findings from studies of normal voice physiology and of voice disorders using high-speed imaging are presented and their relevance is discussed.

Photokymography: a noninvasive method of detecting ischemic segmental myocardial wall motion abnormalities.

The photokymograph is a new and simple noninvasive device for assessing epicardial segmental myocardial wall motion utilizing cardiac fluoroscopy and image intensification. The validity of this technique in detecting wall motion changes occurring with ischemia was assessed in seven closed chest dogs undergoing acute balloon occlusion of the left circumflex coronary artery. Acute occlusion resulted in a prompt change in the analog signal of the photokymogram, characterized first by a decreased systolic inward motion and late systolic outward movement that later became akinetic and dyskinetic. Systolic amplitude decreased 18 +/- 7 percent (mean +/- standard error of the mean) within 5 seconds of occlusion and progressed to systolic outward motion (- 106 +/- 24 percent) at 2 minutes. The time course and type of morphologic changes observed after occlusion were similar to those previously described using invasive methods. Furthermore, such changes preceded electrocardiographic S-T segment elevation. These data suggest that photokymography is a sensitive technique for noninvasive detection of acute ischemic segmental wall motion abnormalities and holds promise as a simple method of detecting ischemic heart disease in man.

Mechanisms of stress-induced ST elevation and negative T-wave normalization studied by serial cardiokymogram in patients with a previous myocardial infarction.

Seventeen patients with a previous myocardial infarction were studied during pacing to characterize the clinical correlates of ST elevation, to analyze the relation between ST elevation and negative T-wave normalization and to investigate the mechanism of these electrocardiographic changes. Myocardial ischemia was evaluated by measurement of blood lactate, and wall motion was analyzed using cardiokymographs concurrently and serially. Results show that ST elevation and negative T-wave normalization were most marked in leads containing abnormal Q waves, that ST elevation greater than or equal to 1 mm during pacing was associated with a significant increase in left ventricular end-diastolic pressure and deterioration of left ventricular wall motion and that the magnitude of ST elevation and negative T-wave normalization was significantly correlated, but the latter appeared earlier and more markedly. In addition, there was no significant correlation between the extent of either ST elevation or negative T-wave normalization and myocardial lactate production. Thus, ST elevation and negative T-wave normalization are caused by abnormal left ventricular wall motion rather than myocardial ischemia. Negative T-wave normalization is a more sensitive marker of abnormal wall motion than ST elevation in patients with a previous myocardial infarction.

Upward displacement of the diaphragm after lung resection.

Upward diaphragmatic displacement was performed in 53 patients after massive lung resection for tuberculosis or bronchiectasis and the data are presented. This technique provides ample room for expansion of the remainder of the lung; it also avoids overexpansion, activation of tuberculous foci, and relapse of bronchiectasis. Diaphragamatic displacement can be used for liquidation of a remaining infected cavity. In children with massive bronchiectasis it serves to conserve two unaffected segments and avoids pneumonectomy. During pneumonectomy in children it prevents significant shift of the mediastinum and progression of scoliosis.

Internal densitometric gating for digital subtraction angiography.

Motion artifacts create a severe problem in digital subtraction angiography (DSA) studies. Periodic motion can be eliminated by "gating," matching a precontrast mask with a postcontrast image at the same phase position in the cycle. Electrocardiogram (EKG) signals are used in cardiac DSA for this purpose. An alternate method relies on the generation of a density-time curve dependent on the attenuation changes of anatomical motion. A densitometric window placed at an appropriate location records the variation, from which individual images are tagged with phase position information encoded as delay time. Results are similar to the EKG gating method for cardiac DSA when using an appropriate window location. Periodic motion caused by superimposed respiration can be suppressed by tracking diaphragm or other object attenuation changes with the same algorithms. Using these techniques permits the nonarbitrary matching of mask and contrast images without physiologic monitoring. The techniques are straightforward and relatively easy to implement on systems designed for rapid digital imaging.

Myocardial wall motion evaluation using amplitude frequency spectral analysis.

Frequency spectral analysis of cardiac wall motion as calculated from the recorded video kymogram are demonstrated. Characteristic harmonics following the fundamental frequency of the cardiac rate have been demonstrated to have an alternating sequential energy distribution as measured from the free margin of the left ventricle of humans. The characteristic patterns occur in approximately 80% of the 50 patients evaluated. The correlation of these harmonics with physiologic events is not yet complete. Amplitude frequency spectral analysis offers an objective method for analysis of cardiac kymography not otherwise possible.

Rate of learning of the conditioned avoidance reflex in rats with various exploratory activity.

Rate of learning of the conditioned avoidance reflex in rats with various spontaneous exploratory activity was studied. Rats with low activity learned more quickly, and the most active rats slowly.

Cardiokymographic wall motion pattern in patients with acute myocardial infarction.

We studied 50 patients with acute myocardial infarction by cardiokymography to record anterior left ventricular wall motion. Systolic outward motion was observed in 46 of 50 patients (92%). Holosystolic outward motion was characteristic of acute anterior infarction (93%) and acute subendocardial infarction (89%) but was less common in acute inferior infarction (29%). Partial systolic outward motion was seen in 8 of the 14 patients with acute inferior infarction, but only in 2 of 36 patients with acute anterior and subendocardial infarction. Cardiokymographic abnormalities were seen in more precordial locations in acute anterior (80%) and subendocardial infarction (97%) than in inferior infarction (74%). Holosystolic outward motion was seen in 75% of all locations in acute anterior and subendocardial infarction and only in 23% in acute inferior infarction. Thus both the extent and the severity of abnormal systolic outward motion clearly separated inferior infarction from anterior and subendocardial infarction. Dynamic changes in wall motion contraction patterns were observed during the course of acute myocardial infarction; both improvement and deterioration were observed. Cardiokymography is a simple, non-invasive method to assess changes in left ventricular segmental wall motion in patients with acute myocardial infarction.

Evaluation of signal-averaged cardiokymography for the detection of ischaemic left ventricular dysfunction.

UNLABELLED: Cardiokymography (CKG) is a non-invasive method for the detection of patients with coronary artery disease (CAD). Issues of the present study were to evaluate the feasibility, sensitivity and specificity of a recently developed signal-averaged CKG system for detecting patients with pharmacologically induced ischaemic left ventricular wall motion abnormalities (WMA) during pharmacologic stress echocardiography (SE). Precordial CKG curves were recorded in 100 consecutive patients who underwent dobutamine-SE for suspected CAD. For interpretation, CKG curves were classified into three different types, depending on the degree of systolic outward motion. CKG test results were regarded as positive (indicating myocardial ischaemia) if there was a change of the baseline CKG type at peak pharmacologic stress. The CKG test results were positive in 18 of 27 patients with a pathologic dobutamine-SE (sensitivity 67%), but did not show any change of the prior CKG type in 57 of 69 patients with a normal SE (specificity 83%). Patients with a true positive CKG test had significantly (P<0.05) more echocardiographic segments with WMA than patients with a false negative CKG test. CONCLUSIONS: Signal-averaged CKG can detect patients with ischaemic ventricular dysfunction. Sensitivity of CKG in detecting patients with WMA depends on the extent of left ventricular ischaemia. Further studies are needed to define the diagnostic value of signal-averaged CKG in the non-invasive detection of patients with suspected CAD.

Quantitative study of mucosal wave via videokymography in canine larynges.

OBJECTIVES: Vocal fold mucosal wave movements are thought to be important in determining voice characteristics and quality. To see these movements, high-speed cinematography and videostroboscopy have been used clinically; however, these techniques have disadvantages that make them impractical for quantitative measurement of mucosal wave movements. This study explored the feasibility of using line-scan cameras for mucosal wave analysis. METHODS: An excised larynx bench model was used to examine the effects of elongation and changes in subglottal pressure on the amplitude, frequency, and phase difference of vocal fold mucosal movements as calculated from line-scan images. RESULTS: The data showed a positive and linear relationship between an increase in subglottal pressure and amplitude of the mucosal wave; elongation of the vocal folds appeared to decrease the amplitude of mucosal wave upheaval at each level of subglottal pressure. Similarly, increase in subglottal pressure had a positive and linear relationship with increase in frequency of vibration; elongation of the vocal folds further increased the frequency at any given subglottal pressure. Phase difference between the movements of the upper and lower margins of the mucosal lips was estimated and did not appear to be significantly affected by changes in subglottal pressure and elongation. CONCLUSION: The data presented in this study are consistent with relationships that we would expect to be true from currently accepted models of vocal fold vibration.

Degenerative progressive myoclonic epilepsy electrokymographic observations.

Clinical and pathological findings in two cases of degenerative progressive myoclonic epilepsy (PME) are described. The clinically difficult task of differentiating a "cerebellar" tremor from an action myoclonus is emphasized. Simultaneous electroencephalography and electrokymography was done, using capacity to ground transients for recording hand movements. This method was found useful in corroborating the cerebellar nature of the remaining disorder, after successful treatment of the myoclonic element with anticonvulsants.