Characterization of parotid gland tumors using diffusion-relaxation correlation spectrum imaging: a preliminary study

AIM

To assess the performance of diffusion-relaxation correlation spectrum imaging (DR-CSI) in the characterization of parotid gland tumors.

MATERIALS AND METHODS

Twenty-five pleomorphic adenomas (PA) patients, 9 Warthin's tumors (WT) patients and 7 malignant tumors (MT) patients were prospectively recruited. DR-CSI (7 b-values combined with 5 TEs, totally 35 diffusion-weighted images) was scanned for pre-treatment assessment. Diffusion (D)-T2 signal spectrum summating all voxels were built for each patient, characterized by D-axis with range 0∼5 × 10-3 mm2/s, and T2-axis with range 0∼300ms. With boundaries of 0.5 and 2.5 × 10-3 mm2/s for D, all spectra were divided into three compartments labeled A (low D), B (mediate D) and C (high D). Volume fractions acquired from each compartment (VA, VB, VC) were compared among PA, WT and MT. Diagnostic performance was assessed using receiver operating characteristic analysis and area under the curve (AUC).

RESULTS

Each subtype of parotid tumors had their specific D-T2 spectrum. PA showed significantly lower VA (8.85 ± 4.77% vs 20.68 ± 10.85%), higher VB (63.40 ± 8.18% vs 43.05 ± 7.16%), and lower VC (27.75 ± 8.51% vs 36.27 ± 11.09) than WT (all p<0.05). VB showed optimal diagnostic performance (AUC 0.969, sensitivity 92.00%, specificity 100.00%). MT showed significantly higher VA (21.23 ± 12.36%), lower VB (37.09 ± 6.43%), and higher VC (41.68 ± 13.72%) than PA (all p<0.05). Similarly, VB showed optimal diagnostic performance (AUC 0.994, sensitivity 96.00%, specificity 100.00%). No significant difference of VA, VB and VC was found between WT and MT.

CONCLUSIONS

DR-CSI might be a promising and non-invasive way for characterizing parotid gland tumors.

Heart rate detection method based on Ballistocardiogram signal of wearable device：Algorithm development and validation

Background

Heart rate, as the four vital signs of human body, is a basic indicator to measure a person's health status. Traditional electrocardiography (ECG) measurement, which is routinely monitored, requires subjects to wear lead electrodes frequently, which undoubtedly places great restrictions on participants' activities during the normal test. At present, the boom of wearable devices has created hope for non-invasive, simple operation and low-cost daily heart rate monitoring, among them, Ballistocardiogram signal (BCG) is an effective heart rate measurement method, but in the actual acquisition process, the robustness of non-invasive vital sign collection is limited. Therefore, it is necessary to develop a method to improve the robustness of heart rate monitoring.

Objective

Therefore, in view of the problem that the accuracy of untethered monitoring heart rate is not high, we propose a method aimed at detecting the heartbeat cycle based on BCG to accurately obtain the beat-to-beat heart rate in the sleep state.

Methods

In this study, we implement an innovative J-wave detection algorithm based on BCG signals. By collecting BCG signals recorded by 28 healthy subjects in different sleeping positions, after preprocessing, the data feature set is formed according to the clustering of morphological features in the heartbeat interval. Finally, a J-wave recognition model is constructed based on bi-directional long short-term memory (BiLSTM), and then the number of J-waves in the input sequence is counted to realize real-time detection of heartbeat. The performance of the proposed heartbeat detection scheme is cross-verified, and the proposed method is compared with the previous wearable device algorithm.

Results

The accuracy of J wave recognition in BCG signal is 99.67%, and the deviation rate of heart rate detection is only 0.27%, which has higher accuracy than previous wearable device algorithms. To assess consistency between method results and heart rates obtained by the ECG, seven subjects are compared using Bland-Altman plots, which show no significant difference between BCG and ECG results for heartbeat cycles.

Conclusions

Compared with other studies, the proposed method is more accurate in J-wave recognition, which improves the accuracy and generalization ability of BCG-based continuous heartbeat cycle extraction, and provides preliminary support for wearable-based untethered daily monitoring.

Identification of major depression patients using machine learning models based on heart rate variability during sleep stages for pre-hospital screening

With the COVID-19 pandemic causing challenges in hospital admissions globally, the role of home health monitoring in aiding the diagnosis of mental health disorders has become increasingly important. This paper proposes an interpretable machine learning solution to optimise initial screening for major depressive disorder (MDD) in both male and female patients. The data is from the Stanford Technical Analysis and Sleep Genome Study (STAGES). We analyzed 5-min short-term electrocardiogram (ECG) signals during nighttime sleep stages of 40 MDD patients and 40 healthy controls, with a 1:1 gender ratio. After preprocessing, we calculated the time-frequency parameters of heart rate variability (HRV) based on the ECG signals and used common machine learning algorithms for classification, along with feature importance analysis for global decision analysis. Ultimately, the Bayesian optimised extremely randomized trees classifier (BO-ERTC) showed the best performance on this dataset (accuracy 86.32%, specificity 86.49%, sensitivity 85.85%, F1-score 0.86). By using feature importance analysis on the cases confirmed by BO-ERTC, we found that gender is one of the most important factors affecting the prediction of the model, which should not be overlooked in our assisted diagnosis. This method can be embedded in portable ECG monitoring systems and is consistent with the literature results.

Optimal Design of Array Coils for Multi-Target Adjustable Electromagnetic Brain Stimulation System

Temporal interference magnetic stimulation is a novel noninvasive deep brain neuromodulation technology that can solve the problem of balance between focus area and stimulation depth. However, at present, the stimulation target of this technology is relatively single, and it is difficult to realize the coordinated stimulation of multiple brain regions, which limits its application in the modulation of multiple nodes in the brain network. This paper first proposes a multi-target temporal interference magnetic stimulation system with array coils. The array coils are composed of seven coil units with an outer radius of 25 mm, and the spacing between coil units is 2 mm. Secondly, models of human tissue fluid and the human brain sphere are established. Finally, the relationship between the movement of the focus area and the amplitude ratio of the difference frequency excitation sources under time interference is discussed. The results show that in the case of a ratio of 1:5, the peak position of the amplitude modulation intensity of the induced electric field has moved 45 mm; that is, the movement of the focus area is related to the amplitude ratio of the difference frequency excitation sources. The conclusion is that multi-target temporal interference magnetic stimulation with array coils can simultaneously stimulate multiple network nodes in the brain region; rough positioning can be performed by controlling the conduction of different coils, fine-tuning the position by changing the current ratio of the conduction coils, and realizing accurate stimulation of multiple targets in the brain area.

Circadian stage-dependent and stimulation duration effects of transcutaneous auricular vagus nerve stimulation on heart rate variability

Transcutaneous auricular vagus nerve stimulation (taVNS) can improve autonomic nerve function and is currently undergoing extensive clinical research; however, its efficacy heterogeneity has caused great controversy. Heart rate variability (HRV), a biomarker reflecting autonomic function, exhibits a time-varying pattern with circadian rhythms, which may be the main reason for the inconsistent stimulation effects. To test this conjecture, we performed isochronous acute stimulation experiments at intervals of 12 h. The results showed that HRV indicators representing vagal nerve activity significantly increased when stimulation was performed in the morning, and the enhancement of high frequency continued into the recovery period. However, the evening stimulation did not yield similar results. In addition, we found that improvements in the measures of autonomic balance were more pronounced in the presence of lower vagal activity. By increasing the stimulation duration, we also found that the effect of taVNS on HRV was not regulated by duration; in other words, HRV changes only had the best effect at the beginning of stimulation. These studies allowed us to determine the optimal stimulation phase and duration and potentially screen the optimal candidates for taVNS.

Sleep EEG-Based Approach to Detect Mild Cognitive Impairment

Mild Cognitive Impairment (MCI) is an early stage of dementia, which may lead to Alzheimer's disease (AD) in older adults. Therefore, early detection of MCI and implementation of treatment and intervention can effectively slow down or even inhibit the progression of the disease, thus minimizing the risk of AD. Currently, we know that published work relies on an analysis of awake EEG recordings. However, recent studies have suggested that changes in the structure of sleep may lead to cognitive decline. In this work, we propose a sleep EEG-based method for MCI detection, extracting specific features of sleep to characterize neuroregulatory deficit emergent with MCI. This study analyzed the EEGs of 40 subjects (20 MCI, 20 HC) with the developed algorithm. We extracted sleep slow waves and spindles features, combined with spectral and complexity features from sleep EEG, and used the SVM classifier and GRU network to identify MCI. In addition, the classification results of different feature sets (including with sleep features from sleep EEG and without sleep features from awake EEG) and different classification methods were evaluated. Finally, the MCI classification accuracy of the GRU network based on features extracted from sleep EEG was the highest, reaching 93.46%. Experimental results show that compared with the awake EEG, sleep EEG can provide more useful information to distinguish between MCI and HC. This method can not only improve the classification performance but also facilitate the early intervention of AD.

The effect of transcutaneous auricular vagus nerve stimulation on HRV in healthy young people

Transcutaneous auricular vagus nerve stimulation (taVNS) has shown positive effects on a variety of diseases. Considering that decreased heart rate variability (HRV) is closely associated with morbidity and mortality for a variety of diseases, it is important to investigate the effect of taVNS on HRV. In Study 1, we conducted a two-stage cross-over trial to compare the effects of taVNS and sham taVNS (staVNS) on HRV. In Study 2, we systematically tested the effects of different taVNS parameters on high frequency (HF) component of HRV. The results showed that taVNS significantly increased measurements of root mean square of the difference between successive RR intervals (RMSSD), percentage of number of pairs of adjacent RR intervals differing greater than 50ms (pRR50), standard deviation of all RR intervals (SDRR), HF. Significantly, enhancement of HF and pRR50 persisted into recovery period. In addition, higher baseline LF/HF ratio was associated with greater LF/HF ratio decrease. Findings also showed that there was no significant difference in measurements of HF between different taVNS parameters. These studies suggest that taVNS could increase HRV, it may help taVNS in the treatment of low HRV related diseases. However, taVNS may not have parameter-specific effects on HRV.

Effects of Alzheimer's disease of varying severity on cardiac and autonomic function

Alzheimer’s disease (AD) is one of the most common neurodegenerative diseases in the elderly. The aim of this study was to explore the effects of AD on cardiac function and autonomic nervous function, and the feasibility of electrocardiogram (ECG) in monitoring the development of AD. APP/PS1 double transgenic mice were used in the Morris water maze (MWM) experiment to evaluate the changes of cognitive ability of AD mice, then the non-invasive ECG acquisition system was used and the changes of ECG intervals and heart rate variability (HRV) were analyzed. AD mice already had cognitive dysfunction at the age of 5 months, reaching the level of mild dementia, and the degree of dementia increased with the course of disease. There were no significant changes in ECG intervals in the AD group at each month. The mean square of successive RR interval differences, percentage of intervals >6 ms different from preceding interval, and normalized high frequency power component in the AD group were decreased and low-to-high frequency power ratio and normalized low frequency power component were increased. Combined with the results of the MWM, it was shown that the regulation mechanism of sympathetic and parasympathetic nerves in mice was already imbalanced in early stage AD, which was manifested as the increase of excessive activity of sympathetic nerves and the inhibition of parasympathetic activities. Therefore, ECG-based analysis of HRV may become a means of daily monitoring of AD and provide an auxiliary basis for clinical diagnosis.

Correlations between microbiota and metabolites after faecal microbiota transfer in irritable bowel syndrome

Faecal microbiota transfer (FMT) consists of the infusion of donor faecal material into the intestine of a patient with the aim to restore a disturbed gut microbiota. In this study, it was investigated whether FMT has an effect on faecal microbial composition, its functional capacity, faecal metabolite profiles and their interactions in 16 irritable bowel syndrome (IBS) patients. Faecal samples from eight different time points before and until six months after allogenic FMT (faecal material from a healthy donor) as well as autologous FMT (own faecal material) were analysed by 16S RNA gene amplicon sequencing and gas chromatography coupled to mass spectrometry (GS-MS). The results showed that the allogenic FMT resulted in alterations in the microbial composition that were detectable up to six months, whereas after autologous FMT this was not the case. Similar results were found for the functional profiles, which were predicted from the phylogenetic sequencing data. While both allogenic FMT as well as autologous FMT did not have an effect on the faecal metabolites measured in this study, correlations between the microbial composition and the metabolites showed that the microbe-metabolite interactions seemed to be disrupted after allogenic FMT compared to autologous FMT. This shows that FMT can lead to altered interactions between the gut microbiota and its metabolites in IBS patients. Further research should investigate if and how this affects efficacy of FMT treatments.

The study on pathological mechanism and solution method for spinal cord ischemia reperfusion injury

OBJECTIVE

We aimed at investigating the pathological mechanism changing of injury during reperfusion injury, reperfusion time correlation and compliance, finding the blood supply and improving the secondary damage.

MATERIALS AND METHODS

A total of 180 patients who underwent a surgical procedure and that received normal saline intraperitoneally immediately after the patients' aortic occlusions were investigated. Patients were divided in three groups. Experimental conditions and programs were designed for various approaches.

RESULTS

Thirty min after the onset of ischemia, we found a decrease in the local blood flow in the lumbar spinal cord, almost -77.48% of the baseline, which was reversed partially by initial reperfusion, even exceeding the baseline level. However, 1 hour after reperfusion, the blood flow was again decreased to the level below the baseline, followed by a decline to 207.13% ± 38.25 PU for 3 h without any recovery. Attenuating this secondary damage with neuroprotective strategies requires an understanding of these pathophysiologic processes.

CONCLUSIONS

This study showed the pathological mechanism changes during reperfusion injury and reperfusion time correlation and compliance, and analyzed some of the important pathophysiologic processes involved in secondary damage after spinal cord injury. Moreover, our research discusses a number of pharmacologic therapies that have either been studied or have future potential for this devastating injury.

Effects of zoledronic acid on bone mineral density around prostheses and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis

INTRODUCTION

To investigate the effect of zoledronic acid on periprosthetic bone mineral density (BMD) and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis.

METHODS

From November 2015 to April 2016, 40 female patients who met the inclusion criteria were randomized into two groups: a control group (calcium + calcitriol) and a zoledronic acid group (calcium + calcitriol + zoledronic acid). At 1 week and 3, 6, and 12 months after operation, BMD was obtained through dual-energy X-ray absorptiometry (DEXA). At pre-operation and at 3, 6, and 12 months after the operation, levels of bone metabolism markers were obtained by serum examination.

RESULTS

Loss of BMD was significantly more pronounced in the control group than in the ZOL group in zones 1, 4, 6, and 7 at 6 months and in zones 1, 2, 4, 6, and 7 at 12 months after the operation. The levels of bone-resorption marker (β-CTX) were significantly lower in the ZOL group than in the control group at 3, 6, and 12 months after operation. The levels of bone-formation marker (TP1NP) performed statistically differences only at 12 months after the operation in these two groups.

CONCLUSIONS

Receiving an intravenous infusion of 5 mg zoledronic acid after THA can effectively reduce periprosthetic BMD loss and improve bone remodeling in females with postmenopausal osteoporosis. Zoledronic acid significantly inhibited bone mass loss in zones 1, 2, 4, 6, and 7 after THA and inhibited bone-resorption marker (β-CTX) to improve bone remodeling. Zoledronic acid treatment is potentially important for patients with osteoporosis after THA.

Comparison of support vector machines based on particle swarm optimization and genetic algorithm in sleep staging

BACKGROUND:

Heart rate variability (HRV) can reflect the relationship between heart rhythm and sleep structure.

OBJECTIVE:

In order to study the effect of support vector machine (SVM) on the results of automatic sleep staging and improve the effectiveness of heart rate variability (HRV) as a sleep structure biomarker, thereby realize long term and non-contact monitoring of sleep quality.

METHODS:

Two kinds of parameter optimization methods are applied to stage sleep experiments when the known SVM can be used for automatic sleep staging. By factor analysis of the time domain, frequency domain, and nonlinear dynamic characteristics of subjects’ HRV signals, the accuracy of the cross-validation method (K-CV) is used as the fitness function value in genetic algorithm (GA) and particle swarm optimization (PSO). Furthermore, GA and PSO are used to optimize the SVM parameters.

RESULTS:

The results show that the accuracy rate of sleep stage is 64.44% when parameters are not optimized, the accuracy rate based on PSO is improved to 78.89% and the accuracy rate based on GA is improved to 84.44%.

CONCLUSION:

Both optimization algorithms can improve the accuracy of SVM for sleep staging and better results based on GA in the experiment.

Association of serum galectin-3 with risks of death and vascular events in acute ischaemic stroke patients: the role of hyperglycemia

BACKGROUND AND PURPOSE

Whether the association between galectin-3 and stroke outcome is modified by fasting plasma glucose (FPG) is unknown. The aim was to evaluate the prognostic effect of galectin-3 amongst ischaemic stroke patients stratified by FPG.

METHODS

In all, 3082 ischaemic stroke patients were included in this study and serum galectin-3 was tested at baseline. The primary outcome was a composite outcome of death and vascular events, and secondary outcomes were death, stroke recurrence and vascular events within 1 year after stroke.

RESULTS

Increased galectin-3 was significantly associated with the primary outcome, stroke recurrence and vascular events in the patients with hyperglycemia but not in those with normoglycemia (P for interaction < 0.05 for all). The multivariate-adjusted hazard ratios (95% confidence intervals) were 1.72 (1.05-2.84), 2.64 (1.14-6.12) and 2.68 (1.33-5.38) for the primary outcome, stroke recurrence and vascular events, respectively. A linear association between galectin-3 and the primary outcome was observed in hyperglycemic patients (P for linearity = 0.007).

CONCLUSION

Increased galectin-3 was associated with the primary outcome, stroke recurrence and vascular events within 1 year after stroke in the patients with hyperglycemia, suggesting that galectin-3 may be an important prognostic factor for ischaemic stroke patients with hyperglycemia.

Serum 25-hydroxyvitamin D deficiency predicts poor outcome amongst acute ischaemic stroke patients with low high density lipoprotein cholesterol

BACKGROUND AND PURPOSE

Current observational studies indicate that a lower vitamin D level is associated with a higher risk of poor ischaemic stroke prognosis. Whether this association is affected by lipid levels is unclear. Our aim was to examine the effect of serum vitamin D especially its deficiency on the global outcome of ischaemic stroke stratified by individual lipid component level.

METHODS

A total of 3181 ischaemic patients from China Antihypertensive Trial in Acute Ischaemic Stroke were included in this study and their baseline serum 25-hydroxyvitamin D levels were tested. They were prospectively followed up for death, major disability and vascular events for 3 months after acute ischaemic stroke. A multivariable logistic model was used to evaluate the association between serum 25-hydroxyvitamin D levels and clinical outcomes of ischaemic stroke in the 3-month period of follow-up in all patients and in different lipid-level subgroups.

RESULTS

Vitamin D deficiency was associated with poor clinical outcomes only in ischaemic stroke patients with high density lipoprotein cholesterol (HDLC) <1.04 mmol/l rather than all patients. The multivariable adjusted odds ratios (95% confidence intervals) of major disability and composite adverse events were 1.98 (1.08-3.63) and 2.24 (1.22-4.12), respectively. There was a significant interaction effect between vitamin D and HDLC levels on major disability and the composite outcome (P for interaction < 0.05 for both). A significant linear trend existed between 25-hydroxyvitamin D and risk of poor prognosis (P = 0.03).

CONCLUSIONS

Vitamin D deficiency may be merely an independent risk factor of poor prognosis in ischaemic stroke patients with low HDLC level.

Effect of single nucleotide polymorphisms in the ATP-binding cassette B1 gene on the clinical outcome of traumatic brain injury

The critical role of ATP-binding cassette B1 (ABCB1) in the function of the blood-brain barrier led us to conducted this prospective study in order to investigate the clinical outcome of patients suffering from severe traumatic brain injury. A total of 182 patients with traumatic brain injury were included in our study. Genotyping of ABCB1 C3435T and G2677T/A was conducted using polymerase chain reaction-restriction fragment length polymorphism. Using multivariate-logistic regression analysis, we found that patients carrying the CT+CC genotype of ABCB1 C3435T were more likely to have a better neurological outcome when compared with the TT genotype (odds ratio = 2.71, 95% confidence interval = 1.12-6.86). However, no significant association was found between the G2677T/A polymorphism and outcome of traumatic brain injury patients. Our study provides important information regarding the prognostic value of ABCB1 C3435T, and the ABCB1 C3435T polymorphism may be used as a predictive marker for the outcome of traumatic brain injury patients.

Clinical significance of fibroblast growth factor receptor-3 mutations in bladder cancer: a systematic review and meta-analysis

Mutations in the fibroblast growth factor receptor-3 (FGFR3) gene are frequently found in bladder cancer, but their prognostic value remains controversial. To globally summarize the association between FGFR3 mutations and the grade and stage of bladder cancer, and to analyze the predictive role of FGFR3 mutations with respect to survival, eligible studies were identified and assessed for quality through multiple search strategies. Risk ratio (RR) data were collected from studies comparing the number of FGFR3 mutants among low-grade and early-stage bladder cancer patients to the number among high-grade and late-stage patients. Hazard ratio (HR) data were collected from studies comparing survival in patients with mutant FGFR3 genes to those with wild-type genes. Studies were pooled, and the RRs of grade and stage and the HRs of survival were calculated. Thirty studies were included in the present meta-analysis. FGFR3 mutations were found to be closely associated with low-grade and early-stage bladder cancer, showing pooled RRs = 2.948 [95% confidence interval (CI) = 2.357-3.688] and 2.845 (95%CI = 2.145- 3.773), respectively. Notably, patients with FGFR3 mutations tended to show better disease-, progress-, and recurrence-free survival (HR = 0.561, 95%CI = 0.405-0.779), and better disease-specific survival (HR = 0.363, 95%CI = 0.266-0.496). This study demonstrated that FGFR3 mutations are closely related to low grade, early stage, and better survival among bladder cancer patients.

Effects of a Cannabinoid Receptor 2 Selective Antagonist on the Inflammatory Reaction to Titanium Particles In Vivo and In Vitro

Wear particle-induced inflammation is a major factor contributing to aseptic loosening in peri-prosthetic tissue. The effects of cannabinoid receptor 2 (CB2) on wear particle-induced inflammation remain unclear. Reverse transcription–polymerase chain reaction and enzyme-linked immunosorbent assay were used to assess the effects of a CB2-selective antagonist, AM630, on regulation of the inflammatory reaction and production of pro-inflammatory cytokines in response to in vitro and in vivo stimulation with titanium particles. In vitro studies, in a model for pre-osteoclast-like cells, demonstrated that AM630 inactivation of CB2 profoundly inhibited interleukin (IL)-1β and tumour necrosis factor (TNF)-α production by RAW264.7 cells stimulated with titanium particles. In vivo findings in a murine air-pouch model of titanium-induced inflammatory osteolysis indicated that AM630 reduced titanium-induced tissue inflammation, seen as a reduction in pouch membrane thickness, inflammatory infiltration and levels of the pro-inflammatory cytokines IL-1β and TNF-α. Thus, inactivation of CB2 by AM630 inhibited the titanium particle-induced inflammatory reaction by reducing pro-inflammatory cytokines in vitro and in vivo.

Hypothalamus syndrome in opticospinal multiple sclerosis

This study describes a case of a patient with OSMS who presented with somnolence, periodic fever, memory impairment, and amenorrhea. Serum prolactin levels were found to be higher than normal. MR imaging showed a bilateral involvement of the hypothalamus. The clinical presentation, laboratory examination, and MR imaging findings suggested a diagnosis of hypothalamus syndrome in this patient.

Effect of combined treatment with methylprednisolone and Nogo-A monoclonal antibody after rat spinal cord injury

The purpose of this study was to investigate the effects of combination therapy with methylprednisolone (MP) and Nogo-66 antagonistic peptide (NEP1-40) on morphological and functional recovery in adult rats subjected to thoracic compression spinal cord injury (SCI). Animals were randomized into four groups: a trauma control group, an MP group, an NEP1-40 group, and a combined treatment group. The inflammatory reaction, neuronal and oligodendrocyte survival, and ultrastructure were assessed at the injury site. Functional analysis was also performed using Basso, Beattie and Bresnahan (BBB) scoring. Rat behaviour was evaluated regularly up to week 4. NEP1-40 did not alter the beneficial effect of MP on haematogenous inflammatory cell infiltration, while combined treatment resulted in greater neuronal and oligodendrocyte survival compared with monotherapy or control. Combination therapy resulted in better locomotor scores. These results in a clinically-relevant SCI model showed that significant neuroprotection can be obtained by combining an initial acute IV injection of MP with continuously infused NEP1-40.

Multi-frequency EIT hardware system based on DSP

Electrical impedance tomography (EIT) is a new functional imaging technique in the biomedical engineering. A multi-frequency hardware EIT system based on digital signal processor (DSP) has been developed, and the system also has been designed using modular structure. Some experiments in vitro tissue are done and their images are generated with the filtered back-projection algorithm using this system in real time. The results show that this system is feasible, stable, convenient and extended.

Isolation of human anti-idiotypic antibodies by phage display for clinical immune response assays

The clinical development of therapeutic proteins requires assays that measure the pharmacokinetic (PK) profile of, and the potential immune response (IR) to, the protein agent. Each assay requires reagents that are highly specific for the therapeutic protein. For therapeutic monoclonal antibodies, anti-CDR-specific, or anti-idiotypic (anti-id), antibodies are an ideal class of reagents suitable for these assays because of their high specificity and affinity to the drug antibody. We generated anti-ids to two human antibodies by antibody phage display using the MorphoSys HuCAL GOLD Fab library. To selectively target the CDR regions, serum and a framework-matched mAb were included as competitors during the phage selection process. Panels of CDR-specific Fabs, with low to sub-nM affinities, were isolated against both targets. The CDR specificity of these Fabs was shown by their lack of binding to a framework-matched control mAb and by competition of this binding with the soluble antigens of the respective therapeutic mAb targets. The candidate anti-id Fabs were able to detect both immobilized and soluble target Ab without being affected by serum, a requirement for both PK assay and the IR bridging assay format. Combinations of the Fabs for PK detection assays were identified by pairwise binding studies, although the pair for one target mAb lacks the desired sensitivity for PK assays. To evaluate their potential as anti-drug antibodies (ADAs), the best Fabs for one of the targets were converted and produced as the required bivalent human mAbs. In comparison to rodent mAbs and primate polyclonal serum, the phage display derived human mAbs were equally effective as reference standards. Our results demonstrate that competition-based phage selection can be an effective method for the isolation of anti-idiotypic antibodies for PK and IR assay development, and in this latter case, overcome limitations of current methods using rodent derived anti-ids.

Effects of selenium and iodine deficiency on bone, cartilage growth plate and chondrocyte differentiation in two generations of rats

OBJECTIVE

The purpose of the current study was to investigate the roles of combined selenium and iodine deficiency in bone development as a possible experimental model of Kashin-Beck osteoarthropathy.

METHODS

Sprague-Dawley rats (n=48) were randomly divided into selenium deficiency (-Se+I), iodine deficiency (+Se-I), combined selenium and iodine deficiency (-Se-I), and selenium and iodine sufficient (+Se+I) groups. Growth of bone and cartilage, and the expression of type X collagen (ColX) and parathyroid hormone-related peptide (PTHrP) were measured in two generations of rats (F(0) and F(1)).

RESULTS

The tibial length in -Se-I rats was significantly shorter in F(1) generation. In +Se-I of F(1) rats, the thickness of the growth plate cartilage, and the proliferative zone was smaller, while in -Se-I rats the growth plate, and the proliferative and hypertrophic zones were also thinner in F(1) generation. In articular cartilage, ColX expression was increased in the deep zone in -Se-I rats of F(0) generation, and in -Se+I, +Se-I and -Se-I rats of F(1) generation. PTHrP expression was increased in the middle zone of -Se+I, +Se-I and -Se-I rats of both F(0) and F(1) generations. In the growth plate cartilage, ColX and PTHrP were expressed in the hypertrophic zone. ColX expression was significantly weaker in -Se+I and -Se-I rats in both F(0) and F(1) generations, while PTHrP expression was stronger in -Se+I, +Se-I and -Se-I rats in both F(0) and F(1) animals.

CONCLUSIONS

Combined selenium and iodine deficiency impaired the growth of bone and cartilage. The changes in the expression of ColX and PTHrP induced by combined selenium and iodine deficiency were compatible to measurements of ColX and PTHrP in Kashin-Beck osteoarthropathy.

The acquisition hardware system with direct digital synthesis and filtered back-projection imaging in electrical impedance tomography

Electrical impedance tomography is a new imaging modality that produces images by computing electrical conductivity within the body. This paper presents a basic acquisition hardware system of Electrical Impedance Tomography with direct digital synthesis (DDS), which is used for studying the human head electrical property. The filtered back-projection algorithm is used for image reconstruction.

[Clinic significance of nm23, collage IV and PCNA expression in non-small cell lung cancer]

BACKGROUND

To study the significance of nm23, collagen IV and PCNA expressions in non-small cell lung cancer.

METHODS

Expressions of the nm23, collagen IV and PCNA in 84 cases of non-small cell lung cancer were examined with SP immunohistochemical technique. Of the 84 cases, there were squamous cell carcinoma 42, adenocarcinoma 42, stage I 27, stage II 24, stage III 24, and stage IV 9. Statistical analysis was performed with Chi-Square test.

RESULTS

Expressions of the nm23, collagen IV and PCNA in 84 cases of non-small cell lung cancer were 60. 7% ( 51/ 84) , 75. 0% ( 63/ 84) and 53. 6% ( 45/ 84) respectively. There was negative correlation between the lymph node metastasis and the expressions of nm23 and collagen IV in squamous cell carcinoma, and the expressions of collagen IV and PCNA were associated with tumor differentiation. No correlation was found between TNM stage and expressions of nm23, collagen IV and PCNA.

CONCLUSIONS

The results indicate that nm23, collagen IV and PCNA participate the modulation of metastasis of non-small cell lung cancer and that they may be used to evaluate the potential of metastasis.

Blockade of CD28-B7, but not CD40-CD154, prevents costimulation of allogeneic porcine and xenogeneic human anti-porcine T cell responses

Despite increasing use of swine in transplantation research, the ability to block costimulation of allogeneic T cell responses has not been demonstrated in swine, and the effects of costimulatory blockade on xenogeneic human anti-porcine T cell responses are also not clear. We have compared the in vitro effects of anti-human CD154 mAb and human CTLA4IgG4 on allogeneic pig T cell responses and xenogeneic human anti-pig T cell responses. Both anti-CD154 mAb and CTLA4IgG4 cross-reacted on pig cells. While anti-CD154 mAb and CTLA4IgG4 both inhibited the primary allogeneic pig MLRs, CTLA4IgG4 (7.88 microg/ml) was considerably more inhibitory than anti-CD154 mAb (100 microg/ml) at optimal doses. Anti-CD154 mAb inhibited the production of IFN-gamma by 75%, but did not inhibit IL-10 production, while CTLA4IgG4 completely inhibited the production of both IFN-gamma and IL-10. In secondary allogeneic pig MLRs, CTLA4IgG4, but not anti-CD154 mAb, induced Ag-specific T cell anergy. CTLAIgG4 completely blocked the indirect pathway of allorecognition, while anti-CD154 mAb blocked the indirect response by approximately 50%. The generation of porcine CTLs was inhibited by CTLA4IgG4, but not by anti-CD154 mAb. Human anti-porcine xenogeneic MLRs were blocked by CTLA4IgG4, but only minimally by anti-CD154 mAb. Finally, CTLA4IgG4 prevented secondary xenogeneic human anti-porcine T cell responses. These data indicate that blockade of the B7-CD28 pathway was more effective than blockade of the CD40-CD154 pathway in inhibiting allogeneic pig T cell responses and xenogeneic human anti-pig T cell responses in vitro. These findings have implications for inhibiting cell-mediated immune responses in pig-to-human xenotransplantation.

[The reconstruction of laryngeal function in subtotal laryngectomy with preservation of arytenoid cartilage]

OBJECTIVE

To evaluate subtotal laryngectomy with preservation of arytenoid cartilage to reconstruct laryngeal function in T3 glottic or supraglottic laryngeal cancer.

METHODS

Subtotal laryngectomy with preservation of arytenoid cartilage to reconstruct laryngeal function was reviewed in 20 patients with T3 laryngeal cancer(3 cases with glottic cancer and 17 cases with supraglottic cancer). Recurrent laryngeal nerve was preserved during surgery. The mucous membranes between cricoid cartilage and pharynx were sewed up accordingly.

RESULTS

All patients had restored phonation and swallowing functions. The 3- and 5-year survival rates were 94.1% and 91.8% respectively. Decannulation rate was 95.0%.

CONCLUSION

Subtotal laryngectomy with preservation of arytenoid cartilage is recommended for T3 laryngeal cancer.

A 20-kDa domain is required for phosphatidic acid-induced allosteric activation of phospholipase D from Streptomyces chromofuscus

Two phospholipase D (PLD) enzymes with both hydrolase and transferase activities were isolated from Streptomyces chromofuscus. There were substantial differences in the kinetic properties of the two PLD enzymes towards monomeric, micellar, and vesicle substrates. The most striking difference was that the higher molecular weight enzyme (PLD57 approximately 57 kDa) could be activated allosterically with a low mole fraction of phosphatidic acid (PA) incorporated into a PC bilayer (Geng et al., J. Biol. Chem. 273 (1998) 12195-12202). PLD42/20, a tightly associated complex of two peptides, one of 42 kDa and the other 20 kDa, had a 4-6-fold higher Vmax toward PC substrates than PLD57 and was not activated by PA. N-Terminal sequencing of both enzymes indicated that both components of PLD42/20 were cleavage products of PLD57. The larger component included the N-terminal segment of PLD57 and contained the active site. The N-terminus of the smaller peptide corresponded to the C-terminal region of PLD57; this peptide had no PLD activity by itself. Increasing the pH of PLD42/20 to 8.9, followed by chromatography of PLD42/20 on a HiTrap Q column at pH 8.5 separated the 42- and 20-kDa proteins. The 42-kDa complex had about the same specific activity with or without the 20-kDa fragment. The lack of PA activation for the 42-kDa protein and for PLD42/20 indicates that an intact C-terminal region of PLD57 is necessary for activation by PA. Furthermore, the mechanism for transmission of the allosteric signal requires an intact PLD57.

Activation of phospholipase D by phosphatidic acid. Enhanced vesicle binding, phosphatidic acid-Ca2+ interaction, or an allosteric effect?

The activity of bacterial phospholipase D (PLD), a Ca2+-dependent enzyme, toward phosphatidylcholine bilayers was enhanced 7-fold by incorporation of 10 mol % phosphatidic acid (PA) in the vesicle bilayer. Addition of other negatively charged lipids such as phosphatidylinositol, phosphatidylmethanol, and oleic acid either inhibited or had no effect on enzyme activity. Only negatively charged lipids with a free phosphate group, phosphatidylinositol 4-phosphate and lyso-PA, had the same effect as PA on enzyme activity. Changes in vesicle curvature and fusion were not the reason for PA activation; rather, a metal ion-induced lateral segregation of PA in the vesicle bilayer correlated with PLD activation. Significant PA activation was also observed with monomer phosphatidylcholine substrate upon the addition of PA vesicles. The PA activation was caused by Ca2+.PA interacting with PLD at an allosteric site other than active site.

Mechanism and structure based inhibitors of phospholipase C enzymes

PI-specific PLC enzymes are a key component of phosphatidylinositol-mediated signaling pathways since the hydrophobic product, diacylglycerol, activates protein kinase C and the water-soluble product, inositol trisphosphate, is involved in Ca2+ mobilization. Nonspecific, or PC-PLC, enzymes can generate diacylglycerol without Ca2+ mobilization. A series of inhibitors, both lipophilic and water-soluble, have been synthesized to target each of these two classes of PLC enzymes. Design of the inhibitors was based on proposed enzyme mechanisms and available crystal structures. The solution conformations of the lipophilic phospholipid analogs, (diheptanoylphosphatidyl(2-O-methyl)inositol for PI-PLC and a dihexanoyl-sn-(3-N-benzylaminoglycero)phosphoramidocholine for PC-PLC, have been determined using NMR methodology and the interaction of these compounds with bacterial enzymes has been examined. Water-soluble inhibitors include strained cyclic phosphonates for PI-PLC and vanadate for PC-PLC. An eventual goal of this work is to generate compounds that specifically target each type of intracellular PLC activity.