Biomedical subjects

Jing Zhai

Publications and source records attributed to Jing Zhai.

13 recordsLinked to original sources

PubMed2006

Pancreatic mucinous lesions: a retrospective analysis with cytohistological correlation.

The diagnosis of mucinous pancreatic lesions, which include mucinous noncystic adenocarcinoma, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), and mucinous metaplasia, is critical, given different clinical management and prognosis. This retrospective study is done to assess the cytological features and pitfalls associated with these entities in cytological samples.A search for pancreatic cytology specimens with histological confirmation of the various pancreatic mucinous lesions was done from 1988 to 2005: 9 mucinous adenocarcinoma, 14 IPMN, 11 MCN, and 3 mucinous metaplasia. The majority (35/37) had been endoscopic ultrasound-guided fine-needle aspirations. The cellularity, background extracellular mucin, epithelial architecture, mucinous nature of the epithelium, cell shape, and nuclear features were evaluated on the cytology material. Of the 22 cytological features evaluated, the presence of three-dimensional clusters, micropapillary structures, and nuclear atypia, which includes nuclear crowding, increased N/C ratio, anisonucleosis, nuclear membrane contour irregularity, clumpy chromatin, and prominent nucleoli, was found to be consistently associated with mucinous adenocarcinoma. There were no statistically significant cytological features, which helped in differentiating IPMN, MCN, and mucinous metaplasia. There was a relatively high false-positive rate in the IPMN group (5/14, 36%). Review of the histological specimen showed severe dysplastic epithelial change in these cases. One false-positive case of mucinous metaplasia (1/3, 33%) showed marked intraepithelial acute inflammation. The cytological diagnosis of mucinous pancreatic lesions remains challenging, except for mucinous noncystic adenocarcinoma. The findings were largely nonspecific in the differentiation between IPMN, MCN, mucinous metaplasia, and incidentally sampled gastrointestinal epithelium. False-positive diagnosis of adenocarcinoma occurs not infrequently in the setting of IPMN with severe dysplastic epithelial change and in lesions with associated acute inflammation, and can be a pitfall in the diagnosis of these lesions.

Adenocarcinoma, Mucinous↗

PubMed2006

Biometric identification using 3D face scans.

Biometrics is an emerging area of bioengineering that pursues the characterization of a person by means of something that the person is or produces. Face recognition is a particularly attractive biometric challenge. Most of the face recognition research performed in the past used 2D intensity images. However, algorithms based on 2D images are not robust to changes of illumination in the environment or orientation of the subject. The ability to acquire 3D scans of human faces removes those ambiguities, since they capture the exact geometry of the subject, invariant to illumination and orientation changes. Unencumbered by those limitations, research in 3D face recognition is now beginning to address a different source of error in biometric recognition: facial geometry deformation caused by facial expressions, which can make 3D algorithms which treat 3D faces as rigid surfaces fail. In this paper, a 3D face recognition framework is proposed to tackle this problem. The framework is composed of three subsystems: expression recognition system, expressional face recognition system and neutral face recognition system. In particular, a system for the recognition of faces with one type of expression (smile) and neutral faces was implemented and tested on a database of 30 subjects. The results proved the feasibility of this framework.

Algorithms↗

PubMed2006

Stress detection in computer users through non-invasive monitoring of physiological signals.

he emerging discipline of Affective Computing pursues the development of computers that could interact with their users taking their affective states into account. For example, if a computer could detect when its user is experiencing stress, it could change the colors and sounds of its user interface to try to calm him/her down. Similarly, the pace of instruction in a computer-based training system could be adapted according to the stress level sensed in the pupil. The research described in this paper aims at the development of a stress detection approach based on automatic monitoring of physiological signals in the computer user. The paper describes the three main aspects of our work: experiment setup for physiological sensing, signal processing to detect the affective state and affective recognition using a learning system. Four signals: Galvanic Skin Response (GSR), Blood Volume Pulse (BVP), Pupil Diameter (PD) and Skin Temperature (ST) are monitored and analyzed to differentiate affective states in the user, in a non-invasive fashion. Results indicate that the physiological signals monitored do, in fact, have a strong correlation with the changes in emotional state of our experimental subjects when stress stimuli are applied to the interaction environment.

Adult↗

PubMed2006

Protective effect of isoflurane and sevoflurane on ischemic neurons and expression of Bcl-2 and ICE genes in rat brain.

OBJECTIVE: To study the protective effect of volatile anesthetics, isoflurane and sevoflurane, on ischemic neurons after cerebral ischemia-reperfusion in rats and its possible molecular mechanism. METHODS: Rat cerebral ischemia-reperfusion model was developed by occlusion of the middle cerebral artery (MCA) and bilateral common carotid arteries (CCAs) 1 h after reperfusion. Using flow cytometry (FCM) and Northern blot hybridization, we calculated the number of apoptotic bodies and detected the expression of bcl-2 mRNA and interleukin-1beta converting enzyme (ICE) mRNA. RESULTS: The apoptotic bodies in hippocampus analyzed by FCM peaked at appeared 24 h after reperfusion, and decreased about 54% and 40%, respectively, after treatment with isoflurane and sevoflurane, as compared with ischemic group. There was no significant difference in the expression of bcl-2 mRNA and ICE mRNA between the inhaled anesthetic groups and ischemic group in hippocampus 24 h after MCA/CCAs occlusion. CONCLUSION: Isoflurane and sevoflurane partially inhibit apoptosis but have no significant effect on the expression of bcl-2 and ICE genes.

Anesthetics, Inhalation↗

PubMed2005

The value of ThinPrep and cytospin preparation in pleural effusion cytological diagnosis of mesothelioma and adenocarcinoma.

The diagnosis of malignant mesothelioma requires an integration of the clinical presentation, radiological studies, and immunohistochemical stain of histological sections. Cytological diagnosis on pleural effusions of mesothelioma and pulmonary adenocarcinoma is highly desirable but debatable. A spectrum of cytological features has been found to be associated more commonly with malignant mesothelioma (e.g., peripheral cytoplasmic skirt, bubbly cytoplasm, cyanophilic cytoplasm, and scalloped border of cell balls) vs. adenocarcinoma (e.g., two-cell population, inspissated cytoplasmic material, cytoplasmic vacuole, angulated and indented nuclei, and smooth border of cell balls) to only name a few. The current study is designed to assess whether the introduction of a liquid-based technology such as ThinPrep (TP) can provide additional diagnostic value in addition to the conventional cytospin Diff-Quik (DQ) preparations. Pleural effusion specimens were prepared with split samples for DQ-stained cytospin and Papanicolaou-stained liquid-based TP. Fifteen pleural effusion samples with immunohistologically confirmed malignant mesothelioma and 13 pleural effusion samples of immunohistologically confirmed pulmonary adenocarcinomas were retrieved from our files. Both DQ cytospin- and Papanicolaou-stained TP slides were evaluated for the known cytological features associated with malignant mesothelioma (25 cytological features) and adenocarcinoma (22 cytological features) without knowledge of the original cytological and histological diagnoses. The McNemar test was used to compare these two cytological preparations for both malignant mesothelioma and pulmonary adenocarcinoma. In the malignant mesothelioma group, 4 of 25 cytological features evaluated, bubbly cytoplasm (P = 0.002), vacuolated cytoplasm (P = 0.005), cell-in-cell arrangement (P = 0.007) and irregular nuclear contour (P = 0.083), were seen more frequently in the DQ cytospin preparation, as opposed to only one feature, nuclear size enlargement (P = 0.008), more readily seen using TP. In the pulmonary adenocarcinoma group, only 1 of 22 cytological features evaluated, presence of angulated or indented nuclei (P = 0.025), was seen more frequently in DQ as opposed to two features, presence of two- cell population (P = 0.04) and presence of micropapillary structures (P = 0.1), were seen more readily in TP. All other cytological features evaluated distinguishing mesotheliomas (20 features) and pleural adenocarcinomas (19 features) were seen equally readily in both types of specimen preparation techniques. This study suggests that the liquid-based TP preparation of pleural effusions does not appear to provide additional diagnostic value when compared with the DQ cytospin preparation in the cytological distinction between mesothelioma and adenocarcinoma in pleural effusions. Most cytological features evaluated, 20 of 25 (mesothelioma) and 19 of 22 (adenocarcinoma), can be seen in both preparation techniques.

Adenocarcinoma↗

PubMed2005

Hands-free human computer interaction via an electromyogram-based classification algorithm.

A four-electrode system for hands-free computer cursor control, based on the digital processing of Electromyogram (EMG) signals is proposed. The electrodes are located over the right frontalis, the procerus, the left temporalis and the right temporalis muscles in the head. This system is meant to enable individuals paralyzed from the neck down (e.g., due to Spinal Cord Injury) to interact with computers using point-and-click graphic interfaces. The intention is to translate electromyograms derived from muscle contractions associated with specific facial movements into five cursor actions, namely: Left, Right, Up, Down and Left-click. This translation is accomplished by a digital signal processing classification algorithm that takes advantage of the divergent spectral nature of the EMG signals produced by the frontalis, temporalis, and procerus muscles, respectively. The effectiveness of the algorithm is evaluated by comparing its performance to that of a previously developed three-electrode EMG-based algorithm, using Matlab simulations. The results indicate that the algorithm classifies with great accuracy and provides a marked improvement over the previous three-electrode system.

Algorithms↗

PubMed2005

User stress detection in human-computer interactions.

The emerging research area of Affective Computing seeks to advance the field of Human-Computer Interaction (HCI) by enabling computers to interact with users in ways appropriate to their affective states. Affect recognition, including the use of psychophysiologcal measures (e.g. heart rate), facial expressions, speech recognition etc. to derive an assessment of user affective state based on factors from the current task context, is an important foundation required for the development of Affective Computing. Our research focuses on the use of three physiological signals: Blood Volume Pulse (BVP), Galvanic Skin Response (GSR) and Pupil Diameter (PD), to automatically monitor the level of stress in computer users. This paper reports on the hardware and software instrumentation development and signal processing approach used to detect the stress level of a subject interacting with a computer, within the framework of a specific experimental task, which is called the 'Stroop Test'. For this experiment, a computer game was implemented and adapted to make the subject experience the Stroop Effect, evoked by the mismatch between the font color and the meaning of a certain word (name of a color) displayed, while his/her BVP, GSR and PD signals were continuously recorded. Several data processing techniques were applied to extract effective attributes of the stress level of the subjects throughout the experiment. Current results indicate that there exists interesting similarity among changes in those three signals and the shift in the emotional states when stress stimuli are applied to the interaction environment.

Adult↗

PubMed2005

[HPLC fingerprinting of total glycosides of Swertia franchetiana].

AIM: To establish a sensitive and specific HPLC method for controlling the quality of total glycosides from Swertia franchetiana H. Smith. METHODS: HPLC method was applied for quality and quantitative assessment of the pharmaceutical extracts from Swertia franchetiana H. Smith. The preparation of sample, the HPLC column, mobile phase, elution mode (isocratic or gradient) and gradient program were optimized in order to obtain HPLC profile. The HPLC system consisted of a SPD-1OAvp pump, SPD-M1OAVP photodiode-array detector (PAD), SIL-10ADVP auto injector. Data were acquired and processed with the CLASS-VP6.1 workstation. HPLC analysis was performed on a Kromasil C18 column (250 mm x 4. 6 mm ID, 5 microm) with methanol and water as mobile phase. The column temperature was set up at 40 degrees C and the flow-rate was 1 mL x min(-1). The reference solution of chemical standards and sample were injected into HPLC system, separately. RESULTS: The HPLC chromatographic fingerprinting of the total glycosides, showing 16 characteristic peaks which were partitioned into three parts: one peak in 0-10 min of retention time, nine peaks containing main 1-7 peaks in 10-15 min of retention time, 6 peaks in 15-30 min of retention time, was established from 10 lots of their products. By comparison of the retention time and the on-line UV spectra and their molecule weights of chemical standards, peak 1-7 were identified as swertiamarin (1), gentiopicroside (2), sweroside (3), isoorientin (4), swertisin (5), isoswertisin (6) and swetianolin (7), respectively. The ratios of peak area between 1-16 were in their extent. Moreover, comparison of the HPLC profiles of the total glycosides, the extracts prepared using another process and the plant indicated that they were closely related to each other. CONCLUSION: The HPLC profiles and quantitative assessment of the total glycosides from Swertia franchetiana H. Smith with high specificity can be used to control their quality and assure lot to lot consistency.

Chromatography, High Pressure Liquid↗

PubMed2004

Peridiverticular colonic hyaline rings (pulse granulomas): report of two cases associated with perforated diverticula.

Hyaline ring (pulse granuloma) is a rare benign lesion of the oral cavity soft tissues characterized by round or oval structures with scalloped borders composed by a collagenous matrix variable associated with inflammatory and foreign bogy giant cells. Vegetable fragments are variably identified. Whereas most cases occur in the oral cavity, it has also been described in other sites such as the lung and rectum. It is thought by most to represent a reaction to foreign materials. We report two incidentally discovered cases of colonic hyaline rings associated with perforated diverticulitis. Vegetable residues were seen in both cases.

Adult↗

PubMed2003

Digital signal processing methods for the evaluation of Blood Volume Pulse (BVP) waveform changes due to exercise.

Previous research by our group has revealed that the Blood Volume Pulse (BVP) waveform recorded using an infrared finger photoplethysmograph (PPG) undergoes changes as the subject performs physical exercise. In particular, a reduction in the depth of the Dicrotic Notch has been observed. There is an interest in characterizing those changes through a single parameter to measure the level of exercise the subject has reached, at any time during an exercise session. This paper reports on the comparison of three Digital Signal Processing approaches designed to reflect the BVP waveform changes through a single parameter, which could be obtained automatically from the digitized BVP signal. The first approach derives a single parameter from the distribution found in the average histogram of several time-aligned and averaged BVP beats. Our second approach analyzes the ratio observed between the first harmonic and higher harmonics in the BVP signal. The third approach evaluates the Dicrotic Notch depth directly from the BVP waveform, tracking sample values about the local minimum defined by the Dicrotic Notch. Our study, involving observations from 10 subjects, ranks these three approaches according to their ability to reflect the changes in BVP due to exercise.

Adult↗

PubMed2003

Optimizing an aerial spray for mosquito control.

The role of proper flight line positioning was demonstrated to be critical for maximizing product efficacy when spraying in crosswinds by small-droplet spray strategies. Characterization studies indicated clearly that aircraft height, small drop emission distribution, and the ambient winds combine to dilute the spray cloud before impacting surface targets. A 5-fold increase in mortality was achieved when we used optimization techniques to position the aircraft during a crosswind treatment test.

Aerosols↗

PubMed2002

Structural and functional implications of the phospholamban hinge domain: impaired SR Ca2+ uptake as a primary cause of heart failure.

OBJECTIVE: The role of sarcoplasmic reticulum (SR) in the onset and progression of heart failure is controversial. We tested the hypothesis that impairment of SR Ca2+ sequestration may be a primary cause for progressive left ventricular (LV) dysfunction and the phospholamban hinge domain may be critical in this process. METHODS: A phospholamban hinge domain mutant (PLB/N27A) was introduced in the cardiac compartment of the phospholamban null mouse. An integrative approach was used to characterize the resulting cardiac phenotype at a structural, cellular, whole organ and intact animal level. RESULTS: NMR analysis revealed a defined alteration in the alpha-helical configuration between residues Q22 to F35 in mutant phospholamban. Transgenic lines expressing similar levels of mutant compared to wild-type phospholamban exhibited super-inhibition of the SR Ca2+ ATPase affinity for Ca2+ (EC50 0.52 microM) in oxalate-supported Ca2+ uptake measurements, which translated into impaired relaxation and attenuated responses to beta-adrenergic stimulation. Importantly, a blunted force-frequency relation was observed in mutant hearts preceding left ventricular dilation. Upon aging to 10 months, the predominantly diastolic dysfunction progressed to congestive heart failure, characterized by induction of a fetal gene program, cardiac remodeling, lung congestion, depressed systolic function and early mortality. CONCLUSION: Increased inhibition of Ca2+ sequestration may be a causative factor in the development of left ventricular dysfunction and myocyte remodeling leading to heart failure. Furthermore, the hinge domain may play an important role in transmitting PLB's regulatory effects on SERCA.

Aging↗

PubMed2002

Evaluation of left ventricular diastolic function from spectral and color M-mode Doppler in genetically altered mice.

Doppler indices of transmitral flow are commonly used to assess noninvasively left ventricular (LV) diastolic function in species larger than mice. The objective of our study was to characterize patterns of LV diastolic function in 2 genetically altered mouse models using Doppler- and color M-mode echocardiography. Phospholamban (PLB) reversibly inhibits the sarcoplasmic reticulum Ca(2+) ATPase (SERCA) and is a key regulator of myocardial relaxation. Twelve-week-old PLB knockout mice (PLB/KO) were examined in parallel with age-matched transgenic mice expressing a mutant form of PLB (PLB/N27A) that exhibited superinhibition of SERCA. Transmitral Doppler flow indexes, including isovolumic relaxation time, the ratio of peak early-to-late filling velocities, and deceleration time of peak early transmitral velocity indicate impaired diastolic filling in the PLB/N27A mutants, but improved LV diastolic function in the PLB/KO mice. In addition, a relatively load-independent parameter of LV relaxation measured by color M-mode Doppler, the propagation velocity of early flow into the LV cavity confirmed the observed differences. We conclude that transmitral filling patterns and color M-mode flow propagation velocity reflect changes in myocardial relaxation in mice with genetically altered levels of PLB and may be useful tools to characterize LV diastolic function in other mouse models of disease.

Animals↗