Osimertinib Covalently Binds to CD34 and Eliminates Myeloid Leukemia Stem/Progenitor Cells

Osimertinib is a third-generation covalent EGFR inhibitor that is used in treating non-small cell lung cancer. First-generation EGFR inhibitors were found to elicit pro-differentiation effect on acute myeloid leukemia (AML) cells in preclinical studies, but clinical trials yielded mostly negative results. Here, we report that osimertinib selectively induced apoptosis of CD34+ leukemia stem/progenitor cells but not CD34- cells in EGFR-negative AML and chronic myeloid leukemia (CML). Covalent binding of osimertinib to CD34 at cysteines 199 and 177 and suppression of Src family kinases (SFK) and downstream STAT3 activation contributed to osimertinib-induced cell death. SFK and STAT3 inhibition induced synthetic lethality with osimertinib in primary CD34+ cells. CD34 expression was elevated in AML cells compared with their normal counterparts. Genomic, transcriptomic, and proteomic profiling identified mutation and gene expression signatures of patients with AML with high CD34 expression, and univariate and multivariate analyses indicated the adverse prognostic significance of high expression of CD34. Osimertinib treatment induced responses in AML patient-derived xenograft models that correlated with CD34 expression while sparing normal CD34+ cells. Clinical responses were observed in two patients with CD34high AML who were treated with osimertinib on a compassionate-use basis. These findings reveal the therapeutic potential of osimertinib for treating CD34high AML and CML and describe an EGFR-independent mechanism of osimertinib-induced cell death in myeloid leukemia.

SIGNIFICANCE

Osimertinib binds CD34 and selectively kills CD34+ leukemia cells to induce remission in preclinical models and patients with AML with a high percentage of CD34+ blasts, providing therapeutic options for myeloid leukemia patients.

Identification of SARS-CoV-2 m6A modification sites correlate with viral pathogenicity

It has recently been found that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) m6A modifications can affect viral replication and function. However, no studies to date have shown a correlation between SARS-CoV-2 m6A modifications and viral pathogenicity. In this study, we analyzed m6A modification in 2,190,667 SARS-CoV-2 genomic RNAs. m6A modifications of SARS-CoV-2 from different lineages, causing mild or severe COVID-19 and showing breakthrough for different vaccines were analyzed to explore correlations with viral pathogenicity. The results suggested that the presence of more m6A modifications in the SARS-CoV-2 N region (positive strand) correlates with weaker pathogenicity. In addition, we identified three m6A modification sites correlating with weak pathogenicity (924 in ORF1ab, 15,659 in ORF1ab, 28,288 in N, 28,633 in N and 29,385 in N, 29,707 in 3'UTR) and one with strong pathogenicity (74 in 5'UTR). These results provide new information for understanding the prevalence of SARS-CoV-2 and controlling the virus.

C1Q labels a highly aggressive macrophage-like leukemia population indicating extramedullary infiltration and relapse

Extramedullary infiltration (EMI) is a concomitant manifestation that may indicate poor outcome of acute myeloid leukemia (AML). The underlying mechanism remains poorly understood and therapeutic options are limited. Here, we employed single-cell RNA sequencing on bone marrow (BM) and EMI samples from a patient with AML presenting pervasive leukemia cutis. A complement C1Q+ macrophage-like leukemia subset, which was enriched within cutis and existed in BM before EMI manifestations, was identified and further verified in multiple patients with AML. Genomic and transcriptional profiling disclosed mutation and gene expression signatures of patients with EMI that expressed high levels of C1Q. RNA sequencing and quantitative proteomic analysis revealed expression dynamics of C1Q from primary to relapse. Univariate and multivariate analysis demonstrated adverse prognosis significance of C1Q expression. Mechanistically, C1Q expression, which was modulated by transcription factor MAF BZIP transcription factor B, endowed leukemia cells with tissue infiltration ability, which could establish prominent cutaneous or gastrointestinal EMI nodules in patient-derived xenograft and cell line-derived xenograft models. Fibroblasts attracted migration of the C1Q+ leukemia cells through C1Q-globular C1Q receptor recognition and subsequent stimulation of transforming growth factor β1. This cell-to-cell communication also contributed to survival of C1Q+ leukemia cells under chemotherapy stress. Thus, C1Q served as a marker for AML with adverse prognosis, orchestrating cancer infiltration pathways through communicating with fibroblasts and represents a compelling therapeutic target for EMI.

A two-stage genome-wide association study identifies novel germline genetic variations in CACNA2D3 associated with radiotherapy response in nasopharyngeal carcinoma

BACKGROUND

Radiotherapy (RT) is the standard treatment for nasopharyngeal carcinoma (NPC). However, due to individual differences in radiosensitivity, biomarkers are needed to tailored radiotherapy to cancer patients. However, comprehensive genome-wide radiogenomic studies on them are still lacking. The aim of this study was to identify genetic variants associated with radiotherapy response in patients with NPC.

METHODS

This was a large‑scale genome-wide association analysis (GWAS) including a total of 981 patients. 319 individuals in the discovery stage were genotyped for 688,783 SNPs using whole genome-wide screening microarray. Significant loci were further genotyped using MassARRAY system and TaqMan SNP assays in the validation stages of 847 patients. This study used logistic regression analysis and multiple bioinformatics tools such as PLINK, LocusZoom, LDBlockShow, GTEx, Pancan-meQTL and FUMA to examine genetic variants associated with radiotherapy efficacy in NPC.

RESULTS

After genome-wide level analysis, 19 SNPs entered the validation stage (P < 1 × 10^- 6), and rs11130424 ultimately showed statistical significance among these SNPs. The efficacy was better in minor allele carriers of rs11130424 than in major allele carriers. Further stratified analysis showed that the association existed in patients in the EBV-positive, smoking, and late-stage (III and IV) subgroups and in patients who underwent both concurrent chemoradiotherapy and induction/adjuvant chemotherapy.

CONCLUSION

Our study showed that rs11130424 in the CACNA2D3 gene was associated with sensitivity to radiotherapy in NPC patients.

TRIAL REGISTRATION NUMBER

Effect of genetic polymorphism on nasopharyngeal carcinoma chemoradiotherapy reaction, ChiCTR-OPC-14005257, Registered 18 September 2014, http://www.chictr.org.cn/showproj.aspx?proj=9546 .

Pericardial adipose tissue-derived leptin promotes myocardial apoptosis in high fat diet-induced obese rats through JAK2/ROS/NKA signaling pathway

Background

Pathophysiologic mechanisms underlying cardiac structural and functional changes in obesity are complex and linked to adipocytokines released from pericardial adipose tissue (PAT) and cardiomyocyte apoptosis. Although leptin is involved in various pathological conditions, its role in paracrine action of pericardial adipose tissue on myocardial apoptosis remains unknown.

Purpose

This study was designed to investigate the role of PAT-derived leptin on myocardial apoptosis in high fat diet-induced obese rats.

Methods and results

Hearts were isolated from lean or high fat diet-induced obese Wistar rats for myocardial remodeling studies. Obese rats had abnormal myocardial structure, diastolic dysfunction, greatly elevated cardiac apoptosis and increased oxidative stress level. Enzyme-linked immunosorbent assay (ELISA) detected significantly higher than circulating leptin level in PAT of obese, but not lean rats. Western blot and immunohistochemical analyses demonstrated increased leptin receptor density in obese heart. H9c2 rat cardiomyoblasts after exposed to PAT-conditioned medium of obese rats exhibited pronounced reactive oxygen species (ROS)-mediated apoptosis, which was partially reversed by leptin antagonist. Moreover, leptin derived from PAT of obese rats inhibited Na+/K+-ATPase activity of H9c2 cells through stimulating ROS, thereby activating calcium-dependent apoptosis. Pretreatment with specific inhibitors revealed that JAK2/STAT3 and PI3K/Akt signaling pathways was involved in the leptin-induced myocardial apoptosis.

Conclusion

PAT-derived leptin induces myocardial apoptosis in high fat diet-induced obese rats via activating JAK2/STAT3/ROS signaling pathway and inhibiting its downstream Na+/K+-ATPase activity.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Nature Science Foundation of ChinaKey Projects of Shaanxi Science and Technology Research and Development Plan

[Investigation of human brucellosis cases in newly affected counties in Sichuan province, 2015-2017]

Objective: To understand the discovery of human brucellosis cases in new affected counties in Sichuan province, 2015-2017, and provide evidences for prevention and control of human brucellosis. Methods: The incidence data and outbreak data of human brucellosis in Sichuan were collected from Chinese Infectious Disease Surveillance Reporting System, and face to face interview, telephone interview and on-line survey were conducted to collect the case information, such as epidemiological characteristics, medical care seeking. Results: The incidence of human brucellosis in Sichuan has increased obviously since 2013, and 103 counties reported human brucellosis cases for the first time. A total of 23 cases of human brucellosis were investigated, and the common symptoms of the cases was fever, accounting for 91.30% (21/23). The cases mainly sought medical care in hospitals under county-level for the first time, accounting for 73.91% (17/23), and the misdiagnosis rate was 91.30% at the first diagnosis (21/23). The median interval between onset and diagnosis was 52 days, and the longest one was 142 days. Only 4.35% (1/23) cases knew human brucellosis, and when they contacted with suspected livestock, the use rate of protective clothing was 30.43% (7/23), the use rate of gloves was 8.70% (2/23), the use rate of mask was 4.35% (1/23), and the rate of washing hands with disinfectant after contact with livestock was 4.35% (1/23). Goat was suspected to be the infection source of all the cases, and 34.75% (8/23) of the cases were from Gansu, Qinghai and other provinces. The overall awareness rate of human brucellosis in the doctors was 34.58% (102/295), and the training rate was 58.31% (172/295). Only 33.33% (11/33) of the hospitals could perform laboratory diagnosis of human brucellosis and 34.78% (8/23) of county CDCs could carry out laboratory test of human brucellosis. Conclusions: The prevention and control of human brucellosis is facing challenge in Sichuan. The misdiagnosis rate was very high in newly affected counties, and the diagnosis were delayed obviously. The awareness of human brucellosis was low in the cases, and their awareness of self-protection was poor. The awareness rate about human brucellosis in doctors was low and they need more training; the capacity of brucellosis laboratory diagnosis in hospitals and CDCs at county-level should be improved.

[Effects and safety of quadratus lumborum block in analgesia after hip arthroplasty]

Objective: To evaluate the efficacy of ultrasound guided quadratus lumborum block combined with non-steroidal anti-inflammatory drugs for postoperative analgesia in patients undergoing total hip arthroplasty. Methods: From January to June 2017, sixty American Society of Anesthesiologists (ASA) physical status Ⅰ to Ⅲ patients, aged 55-75 yr, scheduled for total hip arthroplasty, were randomly divided into control group(group N) and quadratus lumborum block (group R). Ultrasound guided quadratus lumborum block was implemented on the affected side at the end of operation.Then 30 ml 0.33% ropivacaine were administrated in group R, while the control group did not receive the same block. A sufentanil patient-controlled analgesia pump was connected to the patient. The rest visual analogue score (VAS) were recorded at 0 h(T(0)), 3 h(T(1)), 6 h (T(2)), 12 h(T(3)), 24 h (T(4)), 36 h (T(5)) and 48 h(T(6)) after sugery, the VAS scores on movement were evaluated at T(4), T(5) and T(6) time points.The consumption of sufentanil within each period time were recorded.The maximal flexion and abduction degrees of the hip joint were evaluated at 12, 24, 36 and 48 h after operation. The number of patients for rescue pain relief by intravenous analgesia pump during 24 h and 48 h after surgery were counted in both groups. The postoperative adverse effects and overall satisfaction in the two groups were recorded. Results: The VAS at rest in group R were 0.8±0.4, 1.0±0.3, 1.2±0.5, 2.0±0.5, 1.7±0.4 , 1.6±0.5 at T(1), T(2), T(3), T(4), T(5), T(6) respectively, and those in group N were 3.0±0.7, 3.5±0.9, 3.8±0.9, 3.3±1.1, 3.3±0.7, 3.0±0.7 at the same time points. The VAS at rest were lower in group R than those in control group at all time points (F=203.090, 216.354, 203.956, 35.548, 96.332, 80.577, all P<0.01). The VAS on movement in group R were 2.7±0.9, 2.9±0.7 , 2.0±0.6 at T(4), T(5), T(6) respectively , and those in group N were 6.0±1.5, 5.8±1.1, 4.5±1.0. The VAS on movement were also lower in group R than those in control group(F=154.561, 143.224, 141.479, all P<0.01). The maximum flexion degrees in group R were (61±12)degrees, (64±10)degrees, (69±15)degrees and(78±19)degrees at 12, 24, 36, 48 h after operation, and those were (45±11) degrees, (49±10)degrees, (52±12)degrees and(60±14)degrees at the same time points. The maximum flexion degrees in group R were increased more than control group at 12, 24, 36, 48 h after operation(F=34.981, 35.575, 52.106, 41.681, all P<0.01). The abduction degrees in group R were(22±6)degrees, (26±6)degrees, (27±8)degrees and(28±7)degrees at 12, 24, 36, 48 h after surgery, and those in group N were (14±5) degrees, (17±6)degrees, (20±6)degrees and(20±5)degrees. The abduction degrees in group R were increased more than those in group N(F=58.974, 33.402, 19.151, 20.575, all P<0.01). The rates of rescue analgesia for pain relief were 10% and 16.7% at 24 h and 48 h after operation respectively in group R, and those were 100% and 100% in group N. Compared to group N, the rates of rescue analgesia for pain relief in group R were significantly decreased (χ(2)=49.091, 42.857, all P<0.01). The incidences of postoperative nausea and vomiting, pruritus in group R were 3.3% and 3.3% respectively, and those in group N were 23.3% and 20.0%. The incidences of nausea and vomiting, pruritus in group R were lower than those in group N (χ(2)=5.192, 4.875, all P<0.01). The overall satisfaction scores in group R (3.7 ± 1.0 ) were higher than those (1.9±0.7) in the group N(t=7.841, P<0.01). Conclusion: The quadratus lumborum block combined with parecoxib sodium for multimodal analgesia after total hip arthroplasty is effective and provides satisfactory analgesia.

miRNA-185 regulates retained fetal membranes of cattle by targeting STIM1

Retained fetal membranes (RFM) of cows is an important reproductive disturbance, and is related to miRNA-185. Stromal interaction molecule 1 (STIM1), a potential target gene of miRNA-185, could influence placenta release via regulating Ca²⁺ concentration intracellular. The aim of this study was to explore the mechanism of RFM by investigating the regulatory relationship between miRNA-185 and STIM1 in primary uterine caruncel epithelial (UCE) cells. Serum samples of healthy Holstein dairy cows (n = 20) and RFM cows (n = 12), with a similar age, parity, weight, and milk yield, were collected to detect Ca²⁺ concentration at prepartum 1-5 d and postpartum 6, 12 and 24 h. Caruncle tissues were collected from healthy (n = 6) and RFM cows (n = 6) at 12 h after calving. Quantitative polymerase chain reaction (Q-PCR) and western blotting (WB) were performed to detect the mRNA and protein levels of STIM1, respectively. UCE cells were cultured by the explant culture method, further purified, and subsequently treated with PmirGLO-STIM1-Mut + miRNA-185 mimics and mirGLO-STIM1-Mut + miRNA-185 NC. Q-PCR and WB were performed to detect mRNA and protein levels of STIM1 with treated miRNA-185 mimics. Serum levels of Ca²⁺ from RFM cows were abnormally decreased at prepartum 1 d and postpartum 6, 12 and 24 h. Expression level of STIM1 was down-regulated in the caruncle tissue of RFM cows. The luciferase activity was decresed about 30.9% by miRNA-185 mimics (p < 0.01), and the mRNA and protein levels of STIM1 were downregulated miRNA-185-mimics. It was suggesting that miRNA-185 might play an important role in RFM through regulating the expression of STIM1.

HE4 and eIF3a Expression Correlates with Surgical Outcome and Overall Survival in Ovarian Cancer Patients with Secondary Cytoreduction

For recurrent ovarian cancer (ROC), secondary cytoreductive surgery (SCS) is recommended as one optional treatment. However, little is known about the expression and clinical significance of biomarkers during SCS. Human epididymis protein 4 (HE4) is a clinical biomarker for ovarian cancer. Eukaryotic translation initiation factor 3a (eIF3a) is investigated extensively as a potential biomarker for malignancy. The purpose of this study was to investigate the expressions of HE4 and eIF3a at SCS, as well as their associations with surgical outcome and survival in ROC patients. Immunohistochemistry was performed to determine the expressions of HE4 and eIF3a in ovarian tumors taken from both initial and secondary cytoreductive surgery of 35 ROC patients. eIF3a levels were significantly increased at SCS, compared to those at initial cytoreductive surgery (ICS), while HE4 levels were similar. Both HE4 and eIF3a expressions were associated with surgical outcome, in terms of residual tumor. For ICS, patients with high HE4 expression achieved a higher incidence of optimal cytoreduction than those with low HE4 expression (81.0% vs. 33.3%, P = 0.015). A similar result happened in SCS, indicated by higher incidence of no residual tumor in patients with high HE4 expression (76.4% vs. 44.4%, P = 0.046). And high HE4 expression at SCS was more likely to enhance surgical outcome of SCS (77.8% vs. 29.4%, P = 0.038). Therefore, high HE4 expression at either surgery is a predictor of better overall survival (OS) (P = 0.011 and 0.002). Furthermore, patients with an elevated total score (TS) of HE4 between the two surgeries tended to have prolonged OS, compared to those with a non-elevated TS of HE4 (P = 0.076). For eIF3a, initial eIF3a expression was associated with secondary residual tumor (P = 0.035), and the difference in eIF3a expression between the two surgeries correlated with OS (P = 0.052). The expressions of HE4 and eIF3a in tumor specimens correlated with surgical outcome and predicted OS in ROC patients with SCS, thus meriting further investigation.

Downregulation of RIF1 Enhances Sensitivity to Platinum-Based Chemotherapy in Epithelial Ovarian Cancer (EOC) by Regulating Nucleotide Excision Repair (NER) Pathway

BACKGROUND/AIMS

Rap1 interacting factor 1 (RIF1) was deemed to be involved in replication timing regulation and DNA damage response. However, little is known about the role of RIF1 in malignancies. Thus, this study aimed to investigate whether the expression of RIF1 is relevant to the response of epithelial ovarian cancer (EOC) patients to cisplatin chemotherapy and its underlying mechanism.

METHODS

Immunohistochemistry was used for detecting the expression of RIF1 in 72 human ovarian cancer tissues followed by association analysis of RIF1 expression with patients' responses to platinum-based chemotherapy. The survival analysis of ovarian patients based on platinum chemotherapy was analyzed using online databases. RNA interference of RIF1 was carried out in OVCAR3 and A2780 cell lines, to determine the effect of lacking RIF1 expression on cellular responses to cisplatin by using MTS assay. The nucleotide excision repair (NER) capacity of these cells was assessed by using host-cell reactivation and UV sensitivity assay. Western Blot analysis was carried out to determine the effect of RIF1 on the proteins of NER and apoptosis signaling pathway by using RIF1 knockdown cells. BALB/c nude mice model was used for detection of response to cisplatin in vivo.

RESULTS

RIF1 expression was significantly associated with the response of ovarian patients to platinum-based chemotherapy (P< 0.01). In cohorts from online databases, high expression of RIF1 was associated with higher mortality of EOC patients based on platinum chemotherapy (P < 0.01). RIF1 knockdown increased sensitivity to cisplatin in EOC in vitro and in vivo. Deletion of RIF1 impaired the NER activity by inhibiting the NER proteins in ovarian cancer cells. Besides, knockdown of RIF1 enhanced cisplatin-induced apoptosis.

CONCLUSIONS

RIF1 plays an important role in regulating the expression of NER proteins, which in turn contributes to cellular response to cisplatin and EOC patients' response to platinum-based chemotherapy. RIF1 knockdown also promotes cisplatin-induced apoptosis. RIF1 may serve as a novel biomarker for predicting platinum-based chemosensitivity and the prognosis of EOC patients.

Increased HE4 mRNA Expression Correlates with High Level Of eIF3a mRNA And Better Survival in Women with Epithelial Ovarian Cancer

Human epididymis protein 4 (HE4) is one of the most promising biomarkers for epithelial ovarian cancer (EOC). The majority of previous studies utilized the serum level or tissue protein expression of HE4 based upon immunohistochemistry (IHC) to evaluate the role of HE4 in the diagnosis, prognosis, and surveillance of EOC, but very little is known about HE4 mRNA expression. Eukaryotic translation initiation factor 3a (eIF3a) is implicated in oncogenesis and has been investigated extensively as a potential biomarker for malignancy. We previously reported a positive correlation between IHC expressions of eIF3a and HE4 in EOC. In the present study, we performed RT-PCR to determine mRNA expressions of HE4 and eIF3a in 30 normal ovarian tissues, 45 benign, 20 borderline and 94 malignant ovarian tumors. The association of HE4 and eIF3a mRNA expressions with clinicopathological characteristics and patient survivals was investigated. IHC was also performed in the same participants to investigate the correlation between mRNA and protein levels of HE4. HE4 mRNA level was found to be 48.42 ± 74.55 (mean ± SD, range: 0.01-343.99), significantly higher in primary EOC than in the borderline tumor, benign tumor, and normal ovarian tissue (P<0.001). The cutoff value was 13.99 for HE4 to discriminate malignant from benign tumors at 68.1% sensitivity and 93.0% specificity. By Spearman's correlation test, HE4 mRNA expression was indicated to positively correlate with serum CA125 level (r=0.530, P<0.001). Higher HE4 mRNA expression was associated with decreased frequency of lymph node metastasis (P=0.038) and better overall survival (OS) (P=0.007) in primary EOC. Multivariable analysis showed an independent prognostic value of the relative mRNA level of HE4 greater than one for OS (Hazard Ratio, 0.069, 95%CI, 0.009-0.530, P=0.010). eIF3a mRNA expression in women with primary EOC was 0.95 ± 1.19 (mean ± SD, range: 0.06-7.46), which was in a positive linear correlation with HE4 mRNA expression (r=0.310, P=0.002). In the present study, the HE4 mRNA level was unparalleled with IHC expression of HE4 (P>0.05). Collectively, our study revealed that increased HE4 mRNA expression correlates with high level of eIF3a mRNA and better survival in women with EOC, which calls for further investigations.

Overexpression of TRPM7 is associated with poor prognosis in human ovarian carcinoma

BACKGROUND

The melastatin-related transient receptor potential 7 channel (TRPM7) is a nonselective cation channel that has been shown to promote tumor metastasis and progression. In this study, we determined the expression of TRPM7 in ovarian carcinomas and investigated its possible prognostic value.

MATERIALS AND METHODS

Samples were collected from 138 patients with ovarian cancer. Expression of TRPM7 was assessed by real-time PCR and immunohistochemistry, expressed with reference to an established scoring system and related to clinical pathological factors. Kaplan-Meier survival analysis was applied to estimate disease-free survival (DFS) and overall survival (OS). Univariate and multivariate cox regression analyses were performed to correlate TRPM7 expression levels with DFS and OS.

RESULTS

TRPM7 was highly expressed in ovarian carcinoma and significantly associated with decreased disease-free survival (DFS: median 20 months vs. 42 months, P=0.0002) and overall survival (OS: median 27 months vs. 46 months, P<0.001).

CONCLUSION

Overexpression of TRPM7 expression is significantly associated with poor prognosis in patients with ovarian cancer.

The rectenna design on contact lens for wireless powering of the active intraocular pressure monitoring system

This paper proposed a wireless power harvesting system with micro-electro-mechanical-systems (MEMS) fabrication for noninvasive intraocular pressure (IOP) measurement on soft contact lens substructure. The power harvesting IC consists of a loop antenna, an impedance matching network and a rectifier. The proposed IC has been designed and fabricated by CMOS 0.18 um process that operates at the ISM band of 5.8 GHz. The antenna and the power harvesting IC would be bonded together by using flip chip bonding technologies without extra wire interference. The circuit utilized an impedance transformation circuit to boost the input RF signal that improves the circuit performance. The proposed design achieves an RF-to-DC conversion efficiency of 35% at 5.8 GHz.

CD44v6 promotes β-catenin and TGF-β expression, inducing aggression in ovarian cancer cells

A high expression of CD44v6 has been reported in numerous malignant cancers, including stomach, prostate, lung and colon. However, the pathological role and the regulatory mechanisms of CD44v6 have yet to be elucidated. In the present study, the expression levels of CD44v6 were shown to be significantly higher in ovarian cancer tissues, as compared with adjacent normal tissues. Furthermore, the upregulated expression levels of CD44v6 were correlated with disease recurrence and poor survival in patients. The expression of CD44v6 was knocked down in the CAOV3 ovarian cell line, by transfection of a specific small hairpin RNA. The present study showed a correlation between the aggression, viability, invasion and migration of the ovarian cancer cells, with the expression of CD44v6. In addition, the expression of CD44v6 was positively correlated with the expression levels of β‑catenin and tumor growth factor‑β, which indicates that the effects of CD44v6 on ovarian cancer cell aggression may be mediated by these two signaling pathways. In conclusion, the present study provides a novel insight into the association between CD44v6 expression and ovarian cancer. CD44v6 may provide a novel target for the prognosis and treatment of ovarian cancer.

Determinants of the over-anticoagulation response during warfarin initiation therapy in Asian patients based on population pharmacokinetic-pharmacodynamic analyses

To clarify pharmacokinetic-pharmacodynamic (PK-PD) factors associated with the over-anticoagulation response in Asians during warfarin induction therapy, population PK-PD analyses were conducted in an attempt to predict the time-courses of the plasma S-warfarin concentration, Cp(S), and coagulation and anti-coagulation (INR) responses. In 99 Chinese patients we analyzed the relationships between dose and Cp(S) to estimate the clearance of S-warfarin, CL(S), and that between Cp(S) and the normal prothrombin concentration (NPT) as a coagulation marker for estimation of IC₅₀. We also analyzed the non-linear relationship between NPT inhibition and the increase in INR to derive the non-linear index λ. Population analyses accurately predicted the time-courses of Cp(S), NPT and INR. Multivariate analysis showed that CYP2C9*3 mutation and body surface area were predictors of CL(S), that VKORC1 and CYP4F2 polymorphisms were predictors of IC₅₀, and that baseline NPT was a predictor of λ. CL(S) and λ were significantly lower in patients with INR≥4 than in those with INR<4 (190 mL/h vs 265 mL/h, P<0.01 and 3.2 vs 3.7, P<0.01, respectively). Finally, logistic regression analysis revealed that CL(S), ALT and hypertension contributed significantly to INR≥4. All these results indicate that factors associated with the reduced metabolic activity of warfarin represented by CL(S), might be critical determinants of the over-anticoagulation response during warfarin initiation in Asians.

Trial Registration

ClinicalTrials.gov NCT02065388

Validation of a liquid chromatography-electrospray ionization-tandem mass spectrometry method for determination of all-trans retinoic acid in human plasma and its application to a bioequivalence study

A sensitive, reliable and specific LC-MS-MS method was developed and validated for the identification and quantitation of all-trans retinoic acid (ATRA) in human plasma. Acitretin was used as the internal standard (IS). After liquid-liquid extraction of 500 μL plasma with methyl tert-butyl ether (MTBE), ATRA and the IS were chromatographed on a HyPURITY C18 column (150 mm × 2.1 mm, 5 μm) with the column temperature set at 40 °C. The mobile phase was consisted of 40% phase A (MTBE–methanol–acetic acid, 50:50:0.5, v/v) and 60% phase B (water–methanol–acetic acid, 50:50:0.5, v/v) with a flow rate of 0.3 mL/min. The API 4000 triple quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) mode via the positive electrospray ionization interface using the transition m/z 301.4 → 123.1 for ATRA and m/z 326.9 → 177.1 for IS, respectively. The calibration curve was linear over the range of 0.45–217.00 ng/mL (r ≥ 0.999) with a lower limit of quantitation (LLOQ) of 0.45 ng/mL. The intra- and inter-day precisions values were below 8% relative standard deviation and the accuracy was from 98.98% to 106.19% in terms of relative error. The validated method was successfully applied in a bioequivalence study of ATRA in Chinese healthy volunteers.

Effect of probenecid on pharmacokinetics and tolerability of olmesartan in healthy chinese volunteers

BACKGROUND

Olmesartan is an angiotensin II receptor antagonist and is effective and well tolerated in the treatment of arterial hypertension. Probenecid is a well-established hypouricemic agent for the treatment of hyperuricemia and gout.

OBJECTIVE

The goal of this study was to examine the impact of coadministration of probenecid on the pharmacokinetic parameters and tolerability of olmesartan in healthy volunteers.

METHODS

In a randomized, open-label, 2-way crossover study, 12 volunteers received 2 oral treatments (olmesartan alone or olmesartan plus probenecid) separated by 4 days. Blood samples were obtained for a 48-hour pharmacokinetic evaluation after drug administration. Tolerability was assessed by monitoring vital signs and laboratory tests before and after administration of the study drug.

RESULTS

Pharmacokinetic parameters were evaluated in 6 male and 6 female healthy volunteers (mean age, 22 [range, 20-25] years]; weight, 56.0 [range, 51.0-60.0] kg). Probenecid coadministration increased olmesartan Css-av, AUC0→∞, and AUC0-48 by 40%, 50%, and 50%, respectively (P = 0.018, 0.000, 0.000, respectively), but there was no statistical significance for Tmax, t1/2, Css-max, and Css-min between olmesartan plus probenecid and olmesartan alone (P = 0.697, 0.053, 0.521, and 0.734, respectively). No serious adverse event (AE) was reported during the study. The proportion of volunteers with AEs in the olmesartan plus probenecid period (5 of 12 [42%]) was higher than that in the olmesartan-alone period (1 of 12 [8%]). All of the AEs during the olmesartan plus probenecid period were abnormal routine urine test results. The AE in olmesartan-alone period was dizziness. All AEs were classified as mild and considered to be at least possibly related to treatment. All volunteers recovered from the AEs by 2 weeks after the end of the study.

CONCLUSIONS

Probenecid increases the exposure speed of olmesartan by increasing the AUC0-48, AUC0→∞, and Css-av. The combined treatment of olmesartan medoxomil with probenecid may increase the occurrence of genitourinary side effects. ClinicalTrials.gov identifier: NCT01907373.

The differences between American and Chinese patients with Crohn's disease

AIM

The effect of race on Crohn's disease (CD) remains uncertain. This study compared the characteristics of American white patients and Chinese patients with CD.

METHOD

A retrospective chart review was conducted for patients who required management of colorectal CD between 1985 and 2004 at either Cleveland Clinic Florida (CCF) or at the 301 Hospital in China. Data included a family history of CD, smoking history, location of the CD and histopathology.

RESULTS

The mean age of onset in the 153 patients was 29.8 ± 16.4 years for American white patients and 32.4 ± 15.3 years for Chinese patients (not significant). Sixty per cent of American white patients were women vs 37% of Chinese patients (P = 0.003). Twelve per cent of American white patients vs 1% of Chinese patients had a family history of CD (P = 0.016). American white patients had significantly higher rates of arthritis (32%vs 4%), abscess (19%vs 0%), rectal and perineal fistula (52%vs 0%), and disease involving the colon and rectum when compared with Chinese patients (all P < 0.05). American white patients had more colorectal sites involved and higher rates of extraintestinal diseases (40%vs 20%) than Chinese patients (all P < 0.05). Chinese patients had higher rates of ileocaecal disease (82%vs 52%) and deep ulcers (66%vs 24%) in the colorectum (all P < 0.001). There were no statistical differences in the incidence of smoking, perforation, intra-abdominal fistula, stenosis, bowel obstruction, toxic megacolon or granuloma formation.

CONCLUSION

This study found that colorectal CD had a more severe clinical presentation and pathological involvement in American white patients than in Chinese patients.

The relative bioavailability and fasting pharmacokinetics of three formulations of olmesartan medoxomil 20-mg capsules and tablets in healthy Chinese male volunteers: An open-label, randomized-sequence, single-dose, three-way crossover study

BACKGROUND

Olmesartan medoxomil is an angiotensin II-receptor antagonist used in the treatment of hypertension. It is a prodrug and is converted to the pharmacologically active compound on de-esterification by arylesterase in the gastrointestinal tract.

OBJECTIVE

This study investigated the relative bioavailability and fasting pharmacokinetic properties of olmesartan after single doses of a 20-mg test tablet, a 20-mg test capsule, and a commercially available 20-mg reference tablet in healthy Chinese male volunteers. The study was conducted to satisfy Chinese State Food and Drug Administration regulatory requirements for approval of a generic formulation of olmesartan medoxomil.

METHODS

This study had an open-label, randomized-sequence, single-dose, 3-treatment, 3-period crossover design. Healthy volunteers were randomly assigned in a 1:1:1 ratio to receive a single 20-mg dose of the test tablet, test capsule, or reference tablet, each administered after a 12-hour overnight fast, followed by a 1-week washout period and administration of the alternate formulation. Blood samples were obtained at baseline and at 0.5, 1, 1.5,2,2.5,3,4,6,8,12,24,36, and 48 hours after dosing. Tolerability was assessed based on vital signs and laboratory values obtained before and after administration of study drug. The formulations were assumed to be bioequivalent if the 90% CIs for the log-transformed ratios of C(max), AUC(0-t), and AUC(0-∞) were within the predetermined equivalence range (70%-143% for C(max); 80%-125% for AUC(0-t) and AUC(0-∞)), as established by the Chinese State Food and Drug Administration.

RESULTS

Twenty-one healthy male subjects (mean age, 21 years [range, 18-25 years]; weight, 62.1 kg [range, 54.0-80.0 kg]) were enrolled in and completed the study. No period or sequence effect was observed. The mean AUC(0-∞) values for the test tablet, test capsule, and reference tablet were 3993 (1070), 3567 (850), and 3849 (872) ng/mL/h, respectively. The 90% CIs for the log-transformed ratios of test tablet to reference tablet for C(max), AUC(0-48), and AUC(0-∞) were 103.9 to 124.9, 94.0 to 111.5, and 94.4 to 111.7, respectively (all, P = NS). The corresponding 90% CIs for the log-transformed ratios of test capsule to reference tablet were 90.8 to 109.2, 84.9 to 107.9, and 85.1 to 100.7 (all, P = NS). Ten adverse events were reported during the study; 7 subjects complained of pain during blood sampling, and 3 had a blocked venous catheter. No treatment-related adverse events were reported or observed.

CONCLUSIONS

In this single-dose crossover study in healthy Chinese male volunteers, the test and reference formulations of olmesartan medoxomil 20-mg capsules and tablets met the regulatory criteria for assuming bioequivalence. The 3 formulations were well tolerated.

The differences between American and Chinese patients with Crohn's disease

AIM

The effect of race on Crohn's disease (CD) remains uncertain. This study compared the characteristics of American white patients and Chinese patients with CD.

METHOD

A retrospective chart review was conducted for patients who required management of colorectal CD between 1985 and 2004 at either Cleveland Clinic Florida (CCF) or at the 301 Hospital in China. Data included a family history of CD, smoking history, location of the CD and histopathology.

RESULTS

The mean age of onset in the 153 patients was 29.8 ± 16.4 years for American white patients and 32.4 ± 15.3 years for Chinese patients (not significant). Sixty per cent of American white patients were women vs 37% of Chinese patients (P = 0.003). Twelve per cent of American white patients vs 1% of Chinese patients had a family history of CD (P = 0.016). American white patients had significantly higher rates of arthritis (32%vs 4%), abscess (19%vs 0%), rectal and perineal fistula (52%vs 0%), and disease involving the colon and rectum when compared with Chinese patients (all P < 0.05). American white patients had more colorectal sites involved and higher rates of extraintestinal diseases (40%vs 20%) than Chinese patients (all P < 0.05). Chinese patients had higher rates of ileocaecal disease (82%vs 52%) and deep ulcers (66%vs 24%) in the colorectum (all P < 0.001). There were no statistical differences in the incidence of smoking, perforation, intra-abdominal fistula, stenosis, bowel obstruction, toxic megacolon or granuloma formation.

CONCLUSION

This study found that colorectal CD had a more severe clinical presentation and pathological involvement in American white patients than in Chinese patients.

A text input system developed by using lips image recognition based LabVIEW for the seriously disabled

In this paper, we present a text input system for the seriously disabled by using lips image recognition based on LabVIEW. This system can be divided into the software subsystem and the hardware subsystem. In the software subsystem, we adopted the technique of image processing to recognize the status of mouth-opened or mouth-closed depending the relative distance between the upper lip and the lower lip. In the hardware subsystem, parallel port built in PC is used to transmit the recognized result of mouth status to the Morse-code text input system. Integrating the software subsystem with the hardware subsystem, we implement a text input system by using lips image recognition programmed in LabVIEW language. We hope the system can help the seriously disabled to communicate with normal people more easily.

Gender specific association of CYP2C9*3 with hyperlipidaemia in Chinese

AIMS

To investigate the association of CYP2C9*3 and *6 with hyperlipidaemia in Chinese.

METHODS

Four hundred and seventy-six Chinese participated in the study, including 211 uncomplicated hyperlipidaemic patients and 265 healthy controls. PCR-RFLP was used to identify CYP2C9*3 and *6.

RESULTS

CYP2C9*6 was not detected in this study. The allelic frequency of CYP2C9*3 was 0.039 (95% CI 0.022, 0.056). A nonsignificant difference existed in CYP2C9*3 frequencies between males and females (P = 0.605, OR = 1.194, 95% CI 0.610, 2.336), patients and controls (P = 0.063, OR = 0.506, 95% CI 0.244, 1.049) in the total population. However, in the female group, CYP2C9*3 frequency in patients with hyperlipidaemia was significantly lower than that in controls (P < 0.0001, OR = 0.062, 95% CI 0.008, 0.476).

CONCLUSIONS

The association of CYP2C9*3 with hyperlipidaemia was specific for females in this Chinese population.

Ile118Val genetic polymorphism of CYP3A4 and its effects on lipid-lowering efficacy of simvastatin in Chinese hyperlipidemic patients

OBJECTIVES

To determine the frequencies of CYP3A4 alleles (CYP3A4*4,*5 and *6) in Chinese hyperlipidemic patients and to observe the impact of CYP3A4*4 (Ile118Val) genetic polymorphism on the lipid-lowering effects of simvastatin and on the activity of CYP3A4.

METHODS

From hospitalized and non-hospitalized patients, 211 unrelated hyperlipidemic patients were recruited for genotyping. CYP3A4 genotypes were determined by means of polymerase chain reaction and restriction fragment length polymorphism analysis. Of the non-hospitalized hyperlipidemic patients, 8 with CYP3A4*1/*1 and 8 with CYP3A4*1/*4 genotypes were selected to be treated with 20 mg simvastatin daily for 4 weeks. Serum triglycerides (TG), cholesterol (CHO) and low-density lipoprotein (LDL) levels were determined using an automated analyzer (Hitachi 747, Boehringer Mannheim, Mannheim, Germany). CYP3A4 activity was determined by the ratio of 6-hydroxycortisol to free cortisol (6-OHC/FC) in the morning spot urine with a high-throughput liquid chromatography-tandem mass spectrometry method.

RESULTS

Of 211 subjects, 14 (allele frequency 3.32%) were heterozygous for CYP3A4*4 (Ile118Val). Nevertheless, no subjects with a CYP3A4*5 or CYP3A4*6 allele or homozygous for CYP3A4*4 were identified. The ratio of 6beta-OHC/FC was 9.9 +/- 13.7 and 56.6 +/- 35.7 in subjects with the Ile118Val variant (n = 8) and in CYP3A4 wild-type subjects (n = 8), respectively (P = 0.0039). After oral intake of simvastatin 20 mg daily for 4 weeks, the change of serum lipids in CYP3A4*1/*1 and CYP3A4*1/*4 groups showed a significant difference, with a mean decrease in triglycerides and total cholesterol of 38.1 +/- 7.6% versus 25.1 +/- 8.3% (P = 0.034) and of 35.8 +/- 9.6% versus 22.0 +/-20.4% (P = 0.0015) (means +/- SD), respectively. We found no statistically significant difference in the reductions of LDL between subjects carrying the *1 and *4 genotypes (29.0 +/- 7.4% versus 36.8 +/- 8.8%, P = 0.0721).

CONCLUSIONS

The allele frequency of CYP3A4*4 was 3.32% among the hyperlipidemic patients from the Chinese mainland. CYP3A4*4 was an allelic variant related to a functional decrease of CYP3A4 activity, and *4 expression seemed to increase the lipid-lowering effects of simvastatin.

CYP2C9 allele variants in Chinese hypertension patients and healthy controls

BACKGROUND

Cytochromes P450 (CYP) 2C9 are polymorphic enzymes which catalyze a wide spectrum of drugs. It is also responsible for the metabolism of arachidonic acid into EETs. EETs are known to be a vasoactive substance and play an important role in a hypertensive episode. Whether the genetic polymorphism of CYP2C9 will affect the vasoactive effect and consequently affect hypertension formation is still unknown. We investigated the association of CYP2C9*2, CYP2C9*3 and CYP2C9*6 with hypertension.

METHODS

Two hundred and thirty-nine hypertension patients and 265 healthy controls participated in our study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to identify CYP2C9*2, CYP2C9*3 and CYP2C9*6.

RESULTS

CYP2C9*2 and CYP2C9*6 were not detected in our study. The allelic frequency of CYP2C9*3 was 0.015 in hypertension patients in our study. In healthy controls, the allelic frequency of CYP2C9*3 was 0.049. Significant difference existed in CYP2C9*3 frequency between hypertension patients and healthy controls (0.015 for hypertension patients vs. 0.049 for healthy controls; chi2 = 9.728, P < 0.005, OR = 0.277, 95% CI: 0.118-0.651). Also, gender-dependent difference was observed. In females, CYP2C9*3 frequency of hypertension patients was significantly lower than that of healthy controls (chi2 = 11.513, P < 0.001, OR = 0.113, 95% CI: 0.026-0.500).

CONCLUSION

To our knowledge, this is the first report on CYP2C9 frequencies in hypertension patients. Our study implied that CYP2C9*3 had a secondary protective effect in females, which may be useful for studying hypertension pathogenesis and therapeutics.

Fuzzy oxygen control system for the indirect calorimeter of premature infants

The indirect calorimetric system of measuring O2 consumption and CO2 production has been developed for energy expenditure estimation of premature infants. This apparatus requires an input room air mixing with pure oxygen to obtain a stable gas with definite oxygen concentration flowing into the hood for neonatal breath or supplemental oxygen treatments. In this paper, we propose an oxygen control system based on fuzzy control logic to automatically adjust the mixing ratio of room air to pure oxygen gas from the hospital's supply system, designed for premature infants. It is designed to reduce the risks of oxygenic toxicity and retinopathy of prematurity by lowering the overshoot of oxygen concentration. Its performance was evaluated and optimal membership functions were obtained. As a result, the system is quite robust with little effect caused by disturbance and has little or no overshoot when step changing the level of oxygen concentration in the mixed gas.

Unstable Morse Code recognition system with back propagation neural network for person with disabilities

A Morse code auto-recognition system is limited by stable typing speed and stable typing ratio from long to short intervals. For an unstable Morse code typing pattern, the auto-recognition algorithms in the literature are not good enough for applications. This paper adopted a neural network to recognize unstable Morse codes. From an experiment on a teenager with cerebral palsy, the neural network has an average recognition rate up to 93.2%. The recognition rate from an amputee aged 40, who used a prosthesis for typing, it is 97.2% on average. When we compare this to 99.2% for the recognition rate from a skilled expert, the result is quite promising. The neural network has successfully overcome the difficulty of analysing a severely unstable Morse code time series. Since the human typing speed is quite slow in comparison to signal processing by the computer, it also makes it possible to use a neural network for real-time signal recognition.

Electrochemical therapy--comparison with other local treatment methods on rat model

BACKGROUND/AIMS

Electrochemical therapy is an alternative to treat hepatoma. We compare this method with the other local injection methods on rat liver.

METHODOLOGY

Five groups of Wister rats (24 in each) were anaesthetized. Electrochemical therapy was set under direct current, 6 volts, electrodes were 0.5 cm apart, 0.5 cm deep into exposed parenchyma for 10 min. Local injection was done with 50 microL of 95% alcohol, 30 microL of 20% acetic acid, 30 microL of 35% hydrochloric acid, and 30 microL of 20% sodium hydroxide via a 27-gauge needle under direct vision into each rat. Rats and their livers were examined postmortem on day 1, 3, 7 and 14.

RESULTS

In electrochemical therapy, the treated area showed coagulation necrosis and without blood cells on day 1; then the margin became blurred. Mononuclear cell infiltration, reperfusion and fibrous band formation were prominent from day 3 through day 14. In local injection groups, the necrosis is quite irregular and unpredictable. The regeneration went under similar process.

CONCLUSIONS

To destroy tissue locally, electrochemical therapy is unique for its predictability in destructive area and the recovery process and is as effective as the other injection methods. Therefore, it has great potential for hepatoma treatment.

Unstable Morse code recognition with adaptive variable-ratio threshold prediction for physically disabled persons

With one or two switches, Morse code could provide an effective alternative communication channel for individuals with physical limitations. However, most of the physically disabled persons have difficulties in maintaining a stable typing of Morse code, and hence the automated recognition of unstable Morse code is becoming more on demand. In this study, an adaptive variable-ratio threshold prediction (AVRTP) algorithm is proposed to analyze the Morse code time series with variable unit time period and ratio. Two least-mean-square (LMS) predictors are applied to track the dot interval and the dot-dash difference concurrently, and then a predicted threshold based on a variable-ratio decision rule is used to distinguish between dots and dashes. The same method is also applied to identify character-spaces. By the adaptive prediction of variable-ratio threshold, AVRTP has successfully overcome the difficulty of analyzing severely unstable Morse code time series and outperformed the previously proposed adaptive unstable-speed prediction (AUSP) algorithm and LMS and matching (I,MS&M) algorithm. This study concludes with a computer simulation and a preliminary clinical evaluation that demonstrate AVRTP as an efficient and reliable method for unstable Morse code recognition.

Portable and programmable clinical EOG diagnostic system

Monitoring eye movements is clinically important in diagnosis of diseases of the central nervous system. Electrooculography (EOG) is one method of obtaining such records which uses skin electrodes, and utilizes the anterior posterior polarization of the eye. A new EOG diagnostic system has been developed that utilizes two off-the-shelf portable notebook computers, one projector and simple electronic hardware. It can be operated under Windows 95, 98, NT, and has significant advantages over any other similar equipment, including programmability, portability, improved safety and low cost. Especially, portability of the instrument is extremely important for acutely ill or handicapped patients. The purpose of this paper is to introduce the techniques of computer animation, data acquisition, real time analysis of measured data, and database management to implement a portable, programmable and inexpensive contacting EOG instrument. It is very convenient to replace the present expensive, inflexible and large-sized commercially available EOG instruments. A lot of interesting stimulation patterns for clinical application can be created easily in different shape, time sequence, and colour by programming in Delphi language. With the help of Winstar (a software package that is used to control I/O and interrupt functions of the computer under Windows 95, 98, NT), the I/O communication between two notebook computers and A/D interface module can be effectively programmed. In addition, the new EOG diagnostic system is battery operated and it has the advantages of low noise as well as isolation from electricity. Two kinds of EOG tests, pursuit and saccade, were performed on 20 normal subjects with this new portable and programmable instrument. Based on the test result, the performance of the new instrument is superior to the other commercially available instruments. In conclusion, we hope that it will be more convenient for doctors and researchers to do the clinical EOG diagnosis and basic medical science research by using this new creation.

Detection of circulating antigens and antibodies in Toxocara canis infection among children in Chengdu, China

In order to determine the seroprevalence of Toxocara spp. infection in children from Chengdu, we performed an enzyme-linked immunosorbent assay (ELISA) and sandwich ELISA (S-ELISA) with excretory-secretory antigens isolated from second-stage larvae of Toxocara canis (TES-Ag ELISA). The seroprevalences of T. canis antibodies in the children from rural areas, urban districts, and urban districts with recent Ascaris lumbricoides infection were 17.7% (59/333), 2.1% (4/186), and 2.6% (1/38), respectively. Among 63 suspected patients with symptoms of T. canis infection, 31 had positive antibodies. The inhibition assay showed an apparent inhibiting capacity of TES-Ag for the antibody against T. canis larvae. The result of S-ELISA demonstrated that circulating antigens of T. canis larvae could be detected in part of the serum with positive antibodies and that the detection rate for circulating antigens in the sera could be improved by polyethylene glycol-acid treatment. This is the first epidemiological study to confirm the existence of T. canis infection and Toxocara-larvae migrans in Chengdu by the combination of TES-Ag ELISA and S-ELISA.

High resolution electron microscopy of amorphous interlayers between metal thin films and silicon

High-resolution electron microscopy of amorphous interlayers (a-interlayer) formed by solid-state diffusion between metal thin films and silicon is reviewed. In this paper, an overview of the development is presented. Pertinent data obtained on the growth kinetics and structure of a-interlayers in polycrystalline metal thin films on single-crystal silicon are reported. For the Ti/Si, Zr/Si, Hf/Si, V/Si, Nb/Si and Ta/Si systems, the growth of a-interlayer was found to follow a linear law in the initial stage. Si atoms were found to be the dominant diffusing species in the solid phase amorphization in the Ti/Si, Zr/Si, and Hf/Si systems. For the Y/Si system, the stability of amorphous interlayer depends critically on the composition of the amorphous films. Auto-correlation function analysis was utilized to determine the structure of the amorphous interlayers. HRTEM in conjunction with the fast Fourier transform were applied to determine the first nucleated crystalline phase. Simultaneous presence of multiphases was observed to occur in a number of refractory metal/Si systems.

A Morse-code recognition system with LMS and matching algorithms for persons with disabilities

Single-switch communication is an effective auxiliary method for persons with disabilities. However, it is not easy to recognize the Morse codes typed by them. In our earlier proposed Morse code auto-recognition method, using the Least-Mean-Square (LMS) adaptive algorithm, it was demonstrated that the system could successfully recognize the Morse-coded messages at unstable typing speeds. However, the speed variation had to be limited to a range between 0.67 and two times the present speed. In the case of beginners or those with heavy disabilities, this rule can not always be complied with, producing a low recognition rate of 20%. To address this limitation, this paper offers an advanced recognition method which combines the Least-Mean-Square algorithm with a character-by-character matching technique. The recognition rate for this method from simulated and real data from various sources is as high as 75% or more on average. This practical application of the single-switch method means a step forward toward alternative communication for disabled persons.

Adaptive Morse-coded single-switch communication system for the disabled

Automatic recognition of Morse-code is generally developed at a fixed typing rate. However, this is not suitable for the disabled due to their difficulty in maintaining a stable typing rate. In this paper, a system recognizing varying typing speeds is developed using an adaptive technique, the Least-Mean Square (LMS) algorithm. This system helps the disabled have a wide latitude and varying typing speeds in single-switch communication with the Morse-code.

A dynamic model of the cardiac ventricular action potential. II. Afterdepolarizations, triggered activity, and potentiation

The action potential model presented in our accompanying article in this journal is used to investigate phenomena that involve dynamic changes of [Ca2+]i, as described below. Delayed afterdepolarizations (DADs) are induced by spontaneous Ca2+ release from the sarcoplasmic reticulum (SR), which, in turn, activates both the Na(+)-Ca2+ exchanger (INaCa) and a nonspecific Ca(2+)-activated current (Ins(Ca)). The relative contributions of INaCa and of Ins(Ca) to the generation of DADs are different under different degrees of Ca2+ overload. Early afterdepolarizations (EADs) can be categorized into two types: (1) plateau EADs, resulting from a secondary activation of the L-type Ca2+ current during the plateau of an action potential, and (2) phase-3 EADs, resulting from activation of INaCa and Ins(Ca) by increased [Ca2+]i due to spontaneous Ca2+ release from the SR during the late repolarization phase. Spontaneous rhythmic activity and triggered activity are caused by spontaneous Ca2+ release from the SR under conditions of Ca2+ overload. Postextrasystolic potentiation reflects the time delay associated with translocation of Ca2+ from network SR to junctional SR. The cell is paced at high frequencies to investigate the long-term effects on the intracellular ionic concentrations.

A dynamic model of the cardiac ventricular action potential. I. Simulations of ionic currents and concentration changes

A mathematical model of the cardiac ventricular action potential is presented. In our previous work, the membrane Na+ current and K+ currents were formulated. The present article focuses on processes that regulate intracellular Ca2+ and depend on its concentration. The model presented here for the mammalian ventricular action potential is based mostly on the guinea pig ventricular cell. However, it provides the framework for modeling other types of ventricular cells with appropriate modifications made to account for species differences. The following processes are formulated: Ca2+ current through the L-type channel (ICa), the Na(+)-Ca2+ exchanger, Ca2+ release and uptake by the sarcoplasmic reticulum (SR), buffering of Ca2+ in the SR and in the myoplasm, a Ca2+ pump in the sarcolemma, the Na(+)-K+ pump, and a nonspecific Ca(2+)-activated membrane current. Activation of ICa is an order of magnitude faster than in previous models. Inactivation of ICa depends on both the membrane voltage and [Ca2+]i. SR is divided into two subcompartments, a network SR (NSR) and a junctional SR (JSR). Functionally, Ca2+ enters the NSR and translocates to the JSR following a monoexponential function. Release of Ca2+ occurs at JSR and can be triggered by two different mechanisms, Ca(2+)-induced Ca2+ release and spontaneous release. The model provides the basis for the study of arrhythmogenic activity of the single myocyte including afterdepolarizations and triggered activity. It can simulate cellular responses under different degrees of Ca2+ overload. Such simulations are presented in our accompanying article in this issue of Circulation Research.

Cellular responses to electrical stimulation: a study using a model of the ventricular cardiac action potential

A mathematical model of the membrane action potential of a ventricular cardiac cell is used to examine the cellular responses to premature stimulation. Results demonstrate the importance of the slow recovery of INa in determining the response of the cell. Simulated responses to periodic stimulation include monotonic Wenckebach patterns and alternans in APD at normal [K]O. At low [K]O, nonmonotonic Wenckebach periodicities, aperiodic patterns, and enhanced supernormal excitability that results in unstable responses ("chaotic activity") are observed. These observations are consistent with recent experimental results, and the simulations provide insights into the underlying mechanisms at the level of membrane ionic channel kinetics.

Null-balance transducer for isometric force measurements and length control of single heart cells

Recently, an ultrasensitive, optical-fiber-based force transducer was developed to measure the microscopic force of contraction of single heart cells. Since force in cardiac muscle is length and velocity dependent, it is desirable to maintain a constant (isometric) cell length. The original design permits approximately 1% shortening of cell length to occur during twitch contractions. The shortening can be reduced significantly by adding a piezoelectric bimorph actuator and closed-loop control, as described in this paper. As a result, the effective stiffness of the transducer can be increased by a factor of about 100, and cell shortening reduced to approximately 0.01%. For the force probes typically used, this is equivalent to a movement of less than 20 nm for a typical value of 100 nN peak cell force in single frog ventricular cells. The gain in stiffness is obtained without sacrificing sensitivity, although at the expense of frequency response. The new design also permits control of cell length and is applicable to studies of the mechanical stiffness of cardiac cells.

A model of the ventricular cardiac action potential. Depolarization, repolarization, and their interaction

A mathematical model of the membrane action potential of the mammalian ventricular cell is introduced. The model is based, whenever possible, on recent single-cell and single-channel data and incorporates the possibility of changing extracellular potassium concentration [K]o. The fast sodium current, INa, is characterized by fast upstroke velocity (Vmax = 400 V/sec) and slow recovery from inactivation. The time-independent potassium current, IK1, includes a negative-slope phase and displays significant crossover phenomenon as [K]o is varied. The time-dependent potassium current, IK, shows only a minimal degree of crossover. A novel potassium current that activates at plateau potentials is included in the model. The simulated action potential duplicates the experimentally observed effects of changes in [K]o on action potential duration and rest potential. Physiological simulations focus on the interaction between depolarization and repolarization (i.e., premature stimulation). Results demonstrate the importance of the slow recovery of INa in determining the response of the cell. Simulated responses to periodic stimulation include monotonic Wenckebach patterns and alternans at normal [K]o, whereas at low [K]o nonmonotonic Wenckebach periodicities, aperiodic patterns, and enhanced supernormal excitability that results in unstable responses ("chaotic activity") are observed. The results are consistent with recent experimental observations, and the model simulations relate these phenomena to the underlying ionic channel kinetics.

[Influence of zinc deprivation on thymus, spleen development and adenosine deaminase activity in young rats]

This study on the thymus and spleen development and ADA activity was done in young rats with zinc deprivation and supplementation. The serum zinc level, body weight, absolute and relative weight, and ADA activity of the thymus and spleen were compared between the experimental rats and the control group. Above indications were all decreased; especially both the thymus weight and the thymus ADA activity were markedly decreased in the zinc deficient group. The averages of thymic absolute weight, relative weight and ADA activity were dropped by 61.32%, 54.54% and 47.59%, respectively. After zinc supplementation for one month, all the body weight, weight of the thymus and spleen, and ADA activity of the spleen were recovered to the control group's level, while ADA activity of the thymus was 33.03% higher than that of the control group. Our data suggested that zinc was not only an important trace element in maintaining the growth of the body, the development of the thymus and spleen, but it may be an important agent to activate the ADA or to prompt synthesis of ADA.