Biomedical subjects

Bo Zhang

Publications and source records attributed to Bo Zhang.

At least 163 records · Page 9Linked to original sources

PubMed2004

[Vasonatrin peptide attenuates the enhancement of electrically-induced intracellular calcium transient by isoproterenol in rat cardiac myocytes].

The purpose of this study was to investigate the effects of vasonatrin peptide (VNP) on electrically-induced intracellular calcium ([Ca(2+)](i)) transient and mechanism of the effects in the cardiac myocytes. The [Ca(2+)](i) transient was measured with a fluoremetric method. The effects of HS-142-1, 8-Br-cGMP and methylene blue (MB) on [Ca(2+)](i) transient in cardiac myocytes were also determined. Isoproterenol (Iso) at 10(-10)~10(-6) mol/L augmented electrically-induced [Ca(2+)](i) transient dose-dependently, which was (13+/-8)% (P>0.05), (26+/-13)% (P< 0.05), (66+/-10)% (P<0.01), (150+/-10)% (P<0.01) and (300+/-25)% (P<0.01), respectively. These effects were blocked by an beta-adrenergic bloker propranolol (10(-6) mol/L). The effect of Iso (10(-8) mol/L) on [Ca(2+)](i) transient was attenuated in a dose-dependent manner by VNP at 10(-10)~10(-6) mol/L, which was (99+/-3)% (P>0.05), (96+/-2)% (P<0.05), (84+/-6)% (P<0.01), (66+/-3)% (P<0.01) and (62+/-3)% (P<0.01), respectively. 8-Br-cGMP (10(-7)~10(-3) mol/L) aslo attenuated 10(-8) mol/L Iso-induced [Ca(2+)](i) transient dose-dependent. The effect of VNP on [Ca(2+)](i) transient was almost abolished in the presence of HS-142-1 (2x10(-5) mol/L), an antagonist of the natriuretic peptide guanylate cyclase (GC) receptors. MB (10(-5) mol/L), an inhibitor of GC, not only blocked the effect of VNP in myocytes, but also augmented electrically-induced [Ca(2+)](i) transient. VNP and HS-142-1 themselves did not change the [Ca(2+)](i) transient in the cardiac myocytes significantly. But MB augmented the [Ca(2+)](i) transient in the cardiac myocytes significantly. These results suggest that VNP attenuates [Ca(2+)](i) transient induced by Iso. This effect is possibly achieved by binding VNP with the natriuretic peptide GC receptors in the myocytes, leading to an increase in intracellular cGMP.

Animals↗

PubMed2004

Tumor type M2 pyruvate kinase expression in gastric cancer, colorectal cancer and controls.

AIM: Tumor formation is generally linked to an expansion of glycolytic phosphometabolite pools and aerobic glycolytic flux rates. To achieve this, tumor cells generally overexpress a special glycolytic isoenzyme, termed pyruvate kinase type M(2). The present study was designed to evaluate the use of a new tumor marker, tumor M(2)-PK, in discriminating gastrointestinal cancer patients from healthy controls, and to compare with the reference tumor markers CEA and CA72-4. METHODS: The concentration of tumor M(2)-PK in body fluids could be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit (ScheBo Tech, Giessen, Germany). By using this kit, the tumor M(2)-PK concentration was measured in EDTA-plasma of 108 patients. For the healthy blood donors a cut-off value of 15 U/mL was evaluated, which corresponded to 90% specificity. Overall 108 patients were included in this study, 54 patients had a histological confirmed gastric cancer, 54 patients colorectal cancer, and 20 healthy volunteers served as controls. RESULTS: The cut-off value to discriminate patients from controls was established at 15 U/mL for tumor M(2)-PK. The mean tumor M(2)-PK concentration of gastric cancer was 26.937 U/mL. According to the TNM stage system, the mean tumor M(2)-PK concentration of stage I was 16.324 U/mL, of stage II 15.290 U/mL, of stage III 30.289 U/mL, of stage IV 127.31 U/mL, of non-metastasis 12.854 U/mL and of metastasis 35.711 U/mL. The mean Tumor M(2)-PK concentration of colorectal cancer was 30.588 U/mL. According to the Dukes stage system, the mean tumor M(2)-PK concentration of Dukes A was 16.638 U/mL, of Dukes B 22.070 U/mL, and of Dukes C 48.024 U/ml, of non-metastasis 19.501 U/mL, of metastasis 49.437 U/mL. The mean tumor M(2)-PK concentration allowed a significant discrimination of colorectal cancers (30.588 U/mL) from controls (10.965 U/mL) (P<0.01), and gastric cancer (26.937 U/mL) from controls (10.965 U/mL) (P<0.05). The overall sensitivity of tumor M(2)-PK for colorectal cancer was 68.52%, while that of CEA was 43.12%. In gastric cancer, tumor M(2)-PK showed a high sensitivity of 50.47%, while CA72-4 showed a sensitivity of 35.37%. CONCLUSION: Tumor M(2)-PK has a higher sensitivity than markers CEA and CA72-4, and is a valuable tumor marker for the detection of gastrointestinal cancer.

Biomarkers, Tumor↗

PubMed2004

[Treatment techniques of harvesting injury of donor renal blood vessels].

OBJECTIVE: To study the treatment technique for harvesting injury of donor blood vessels for the clinic application. METHODS: The data of 32 renal transplantation patients with injury of graft blood vessels were retrospectively reviewed. 60 renal transplantation patients with non-injury during the same term were selected as the control group. The treatment techniques for harvesting injury of graft blood vessels mainly includes end-to-end anastomosis of graft artery, side-to-side anastomosis of branch artery, end-to-side anastomosis of branch artery to the main renal artery, reconstruction of multiple segmental arteries by using iliac arterial grafts from cadaveric donors or recipients on the workbench, repairs of injuries for the smaller segmental/polar arteries by using inferior epigastric artery, end-to-end anastomosis of the lower thick segmental/polar arteries with the iliac internal arterial by placing kidney upside down. RESULTS: Those injured included 28 arterial and 4 venous. Average bench surgery time was 42 minutes. Mean warm ischemic time was 31 minutes. No death occurred at an average follow-up of 3.5 years (1 - 5 years). There was no statistical difference in the 1-year graft survival, postoperative 1-year acute rejection, delayed graft function (DGF) and the incidence of constriction of vascular anastomosis rate (96.9%, 12.5%, 21.9%, 3.1%, respectively) compared with non-reconstructed kidneys during the same term (98.3%, 11.7%, 18.3%, 1.7%, P > 0.05, respectively). CONCLUSION: The flexible and appropriate application of different vascular reconstruction means and satisfactory surgery techniques play an important role in assuring quality of kidney with harvesting blood vessels injury and donor kidney availability.

Adolescent↗

PubMed2004

[Clinical investigation of renal angiomyolipoma].

OBJECTIVE: To study the diagnosis and management of renal angiomyolipoma (RAML), and to identify risk factors affecting spontaneous angiomyolipoma rupture. METHODS: The data of 68 patients with RAML from 1989 to 2002 were retrospectively reviewed. These patients were divided in two groups on the basis of tumor size, 35 patients in group A ( 4 cm). RESULTS: Seven patients were identified by image-guided percutaneous biopsy, and no major complications was noted. Sixteen patients with RAML were examined with angiography and 9 of 16 patients had got spontaneous rupture. 41.2% of patients were symptomatic, 4 cases (11.4%) in group A and 24 (72.7%) cases in group B (P < 0.01). There were significant differences in mean tumor size (11.6 cm +/- 5.1 cm vs 5.3 cm +/- 2.9 cm, P < 0.01) and mean aneurysm size (13.6 mm +/- 5.8 mm vs 2.6 mm +/- 3.0 mm, P < 0.01) between 9 cases of the ruptured tumor and 59 cases of unruptured tumor, 9 cases of the ruptured and 7 cases of unruptured tumor with angiography, respectively. Treatment consisted of conservative observation in 10 patients (no radiographic changes during the follow-up of 2 - 7 years); partial nephrectomy in 14 patients, tumor enucleation in 30 patients, total nephrectomy in 14 and posterior laparoscopic nephrectomy in 3 (no recurrence and complication correlation to operation during the follow-up of 2 - 144 months). CONCLUSIONS: It is an important role that percutaneous biopsy guided by ultrasonography or computerized tomography performs in managing suspicious and/or indeterminate RAML. A higher probability of rupture is related to tumor and/or aneurysms size. Nephron-sparing surgery is the first choice for surgical treatment of RAML.

Adolescent↗

PubMed2004

A novel piezoelectric quartz micro-array immunosensor based on self-assembled monolayer for determination of human chorionic gonadotropin.

A novel multi-channel 2 x 5 model of piezoelectric quartz micro-array immunosensor has been developed for quantitative detection of human chorionic gonadotropin (hCG) in serum or urine samples. Every crystal unit of the fabricated piezoelectric hCG micro-array immunosensor can oscillate independently without interfering each other. A 2 x 5 model of micro-array immunosensor as compared with a one-channel immunosensor can provide eight times higher detection speeds for hCG assay. The anti-hCG antibody is deposited on the gold electrode's surface of 10 MHz quartz AT-cut crystal by self-assembled technique using sulfosuccinimidyl 6-[3'-(2-pyridyldithio) propionamido] hexanoate (Sulfo-LC-SPDP), and serves as an antibody recognizing layer. The highly ordered self-assembled monolayers (SAM) ensure well-controlled surface structure and offer many advantages to the performance of the sensor. Compared with conventional antibody immobilization methods, the amount and the reaction activity of antibody monolayer coated by the SAM binding are bigger than those by the SPA method, and less non-specific binding caused by other analytes in sample is found. Under the optimized experimental conditions, the results showed that micro-array immunosensor quantitatively detected serum or urine hCG in the range of 2.5-500 mIU/ml with high precision (CV<5%); other hormones in human serum and urine did not interfere with the determination markedly. Serum and urine samples of 60 patients were detected by the micro-array immunosensor, and the results agreed well with those given by the commercial radioimmunoassay test kit, with correlation coefficient of 0.92. After regeneration with urea solution the coated immunosensor can be reused five times without appreciable loss of activity.

Biosensing Techniques↗

PubMed2004

Influence of age and hypertension on the association between small artery compliance and coronary artery disease.

Small artery elasticity index (SAEI) as determined by a new non-invasive pulse-wave contour analysis has been used to identify abnormalities of the arterial wall associated with aging, hypertension (HT), endothelial dysfunction, and coronary artery disease (CAD). The present study examined the influence and interaction of CAD risk factors on the association between SAEI in risk-associated patients with CAD (case subjects, n = 178) and without CAD (control subjects, n = 202). Case subjects had a lower SAEI than control subjects, and age was consistently and negatively correlated with SAEI. The HT was related to reduced SAEI in female subjects overall and in male case subjects. In male patients with hypertension, the association between SAEI and CAD was significant (P < .05) after considering conventional risk factors of CAD. In conclusion, age and HT should be considered when using SAEI in the early diagnosis of CAD, and lower SAEI could be of greatest diagnostic value in male patients with HT.

Adult↗

PubMed2004

Inhibition of cholesteryl ester transfer protein increases serum apolipoprotein (apo) A-I levels by increasing the synthesis of apo A-I in rabbits.

BACKGROUND: Inhibition of cholesteryl ester transfer protein (CETP) is an effective way to increase HDL levels in animals and humans. The effects of a CETP inhibitor, JTT-705, on the in vivo kinetics of apolipoprotein (apo) A-I and apo A-I gene expression in the liver and intestine were investigated. METHODS: Japanese White rabbits were randomly fed normal rabbit chow LRC-4 (n=10, control) or a food admixture of LRC-4 and 0.75% JTT-705 (n=10, treated) for 7 months. An in vivo kinetics study of apo A-I was performed by injecting rabbit 125I-apo A-I, and apo A-I mRNA levels were quantified by RT-PCR. RESULTS: JTT-705 significantly inhibited CETP activities, increased serum levels of HDL-cholesterol (C), HDL2-C, HDL-phospholipid, and apo A-I, and decreased HDL-triglyceride levels. The synthetic rate of apo A-I was higher in the treated rabbits than in control rabbits (13.7 +/- 2.6 versus 9.5 +/- 1.3 mg/kg per day, P < 0.05), while the fractional catabolic rate was similar in the two groups. JTT-705 increased apo A-I mRNA levels in the liver without affecting those in the intestine. CONCLUSION: Inhibition of CETP activity by JTT-705 increases HDL levels by increasing the synthesis of apo A-I, suggesting that it could be a promising therapeutic approach for atherosclerosis.

Amides↗

PubMed2004

T13M mutation of lecithin-cholesterol acyltransferase gene causes fish-eye disease.

BACKGROUND: Lecithin-cholesterol acyltransferase (LCAT) esterifies free cholesterol (FC) in plasma and plays a crucial role in the maturation of prebeta1-HDL (lipid-poor HDL) into alpha-migrating HDL (spherical HDL). Natural mutations of LCAT gene cause familial LCAT deficiency (FLD) or fish-eye disease (FED). The relationship between mutations and their phenotypes gives important clues to the functions of specific regions of LCAT. We investigated the first homozygous case with a substitution of threonine to methionine at codon 13 (T13M) of LCAT gene. METHODS: We evaluated LCAT activity, LCAT distribution among HDL subfractions and conversion of prebeta1-HDL to alpha-migrating HDL by native two-dimensional gel electrophoresis (N-2DGE). RESULTS: The proband had corneal opacity, severe hypo-alpha-lipoproteinemia, half-normal LCAT activity and near normal cholesteryl ester/total cholesterol (TC) ratio in plasma. These features were characteristic of FED. Plasma prebeta1-HDL concentration was near normal, but not converted to alpha-migrating HDL during 37 degrees C incubation. As expected, alpha-migrating HDL (especially large particles) was markedly reduced. In the immunoblot against LCAT, the small alpha-migrating HDL from the proband had much less LCAT in this patient than in controls. CONCLUSION: T13M mutation of LCAT gene causes FED.

Adult↗

PubMed2004

Simple and rapid detection of uncoupling protein-2 - 866G/A polymorphism by mutagenically separated polymerase chain reaction.

BACKGROUND: Uncoupling protein-2 (UCP2), a recently identified member of the mitochondrial transporter superfamily, is a candidate gene for obesity. A common G/A polymorphism in the UCP2 promoter region is associated with enhanced adipose tissue mRNA expression in vivo. METHODS: We developed a rapid and simple method, mutagenically separated polymerase chain reaction (MS-PCR) for genotyping UCP2 - 866G/A polymorphism. Two reverse mutagenic allele-specific primers of different lengths for the UCP2 - 866G/A polymorphic site were paired with the same forward primer in the same PCR reaction. RESULTS: Agarose gel electrophoresis (3.5%) showed at least one of the two allelic products and provided a within-assay quality control to exclude false-negative results. The 203-bp fragment of the PCR products was A allele-specific and the 183-bp fragment was G allele-specific. The frequencies of the UCP2 - 866G/A genotypes in 72 Japanese subjects were AA: 21 (29.2%), AG: 32 (44.4%), and GG: 19 (26.4%). The results were confirmed by the PCR-RFLP genotyping method, in which a 360-bp fragment of PCR products was cut into 290- and 70-bp fragments by the restriction enzyme MluI when the G allele was present. This Japanese group showed a higher frequency of the AA genotype, which is associated with a low prevalence of obesity, than Caucasian populations. CONCLUSIONS: The MS-PCR technique is a simple, rapid, and reliable method for genotyping UCP2 - 866G/A polymorphism.

Adolescent↗

PubMed2004

Effects of aluminum chloride on sodium current, transient outward potassium current and delayed rectifier potassium current in acutely isolated rat hippocampal CA1 neurons.

The effects of aluminum chloride (AlCl3) on sodium current (INa), the transient outward potassium (IA) and delayed rectifier potassium currents (IK) in hippocampal CA1 neurons of rats were studied using the whole cell patch-clamp technique. AlCl3 decreased INa, IA, and IK in a partly reversible, dose and voltage-dependent manner. AlCl3 prolonged the time to peak of INa, and increased the inactivation time constants of INa and IA . In addition, 1000 microM AlCl3 shifted the voltage dependence of steady-state activation of INa, IA and IK toward positive potential, and the voltage dependence of steady-state inactivation of INa, IA toward negative potential. These results imply that AlCl3 could affect the activation and inactivation courses of sodium current and potassium current of rat hippocampal CA1 neurons, which may contribute to damage of the central nervous system by aluminum.

Aluminum Chloride↗

PubMed2004

Heat Loss Prevention (HeLP) in the delivery room: A randomized controlled trial of polyethylene occlusive skin wrapping in very preterm infants.

OBJECTIVES: To determine if polyethylene occlusive skin wrapping of very preterm infants prevents heat loss after delivery better than conventional drying and to evaluate if any benefit is sustained after wrap removal. STUDY DESIGN: This was a randomized controlled trial of infants <28 weeks' gestation. The experimental group was wrapped from the neck down. Only the head was dried. Control infants were dried completely. Rectal temperatures were compared on admission to the neonatal intensive care unit immediately after wrap removal and 1 hour later. RESULTS: Of 55 infants randomly assigned (28 wrap, 27 control), 2 died in the delivery room and 53 completed the study. Wrapped infants had a higher mean rectal admission temperature, 36.5 degrees C (SD, 0.8 degrees C), compared with 35.6 degrees C (SD, 1.3 degrees C) in control infants ( P = .002). One hour later, mean rectal temperatures were similar in both groups (36.6 degrees C, SD, 0.7 degrees C vs 36.4 degrees C, SD, 0.9 degrees C, P = .4). Size at birth was an important determinant of heat loss: Mean rectal admission temperature increased by 0.21 degrees C (95% CI, 0.04 to 0.4) with each 100-g increase in birth weight. CONCLUSIONS: Polyethylene occlusive skin wrapping prevents rather than delays heat loss at delivery in very preterm infants.

Apgar Score↗

PubMed2004

Serum high-density lipoprotein-cholesterol levels modify the association between plasma levels of oxidatively modified low-density lipoprotein and coronary artery disease in men.

We investigated the association among plasma levels of oxidatively modified low-density lipoprotein (Ox-LDL), high-density lipoprotein-cholesterol (HDL-C), and the prevalence of coronary artery disease (CAD) in a case-control study. Cases (n = 183, male [M]/female [F]:138/45, age: 64.9 +/- 10.6 years) were defined as patients with angiographically proven coronary atherosclerosis (>/=50% stenosis) and controls were subjects with normal coronary arteries (n = 74, M/F:36/38, age: 57.6 +/- 14.4 years). Plasma Ox-LDL levels were measured by a sensitive detection method using the monoclonal antibody DLH3. In women, both Ox-LDL and lipid variables were similar between cases and controls. In men, cases had significantly lower (P <.05) levels of HDL-C (39.1 +/- 10.3 v 42.8 +/- 10.9 mg/dL) and apolipoprotein (apo) A-I than controls, while the difference in Ox-LDL between cases and controls was not significant (1.05 +/- 0.79 and 0.83 +/- 0.65 ng/10 microg LDL protein, respectively). However, HDL-C levels interacted with the association between Ox-LDL levels and CAD in males: increased Ox-LDL levels were significantly associated with CAD after controlling for age when HDL-C levels were high, but were not associated with CAD when HDL-C levels were low, as assessed by a multiple logistic regression analysis. In addition, the combination of HDL-C and Ox-LDL levels was a better indicator for CAD in males than HDL-C levels alone (-2 log likelihood, 24.1 v 19.4) after controlling for age and conventional risk factors of CAD, while Ox-LDL levels were not significantly associated with CAD. HDL-C levels interact with the association between plasma Ox-LDL levels and CAD in men, and increased Ox-LDL levels are an indicator of CAD in male subjects with high HDL-C levels.

Adult↗

PubMed2004

A comparative study of two modeling approaches in neural networks.

The neuron state modeling and the local field modeling provides two fundamental modeling approaches to neural network research, based on which a neural network system can be called either as a static neural network model or as a local field neural network model. These two models are theoretically compared in terms of their trajectory transformation property, equilibrium correspondence property, nontrivial attractive manifold property, global convergence as well as stability in many different senses. The comparison reveals an important stability invariance property of the two models in the sense that the stability (in any sense) of the static model is equivalent to that of a subsystem deduced from the local field model when restricted to a specific manifold. Such stability invariance property lays a sound theoretical foundation of validity of a useful, cross-fertilization type stability analysis methodology for various neural network models.

Algorithms↗

PubMed2004

Effects of the NA+ channel blocker pilsicainide on the electrophysiologic properties of pulmonary veins in patients with atrial fibrillation.

INTRODUCTION: Na+ channel blockers are used to treat atrial fibrillation (AF). However, the effects of Na+ channel blockers on the electrophysiologic properties of pulmonary veins (PVs) are not well characterized. The aim of the present study was to evaluate the effect of the pure Na+ channel blocker pilsicainide on the PVs. METHODS AND RESULTS: PV mapping using a basket catheter was performed in 28 patients with paroxysmal AF. Twenty-eight PVs, including 20 left superior and 8 right superior PVs, were studied. Programmed stimulation was performed in the distal PV and PV-left atrial (LA) junction before and after infusion of pilsicainide (1 mg/kg). Pilsicainide significantly prolonged the effective refractory period (ERP) of the distal PV from 163 +/- 44 msec to 192 +/- 53 msec (P < 0.001), PV-LA junction from 227 +/- 48 msec to 235 +/- 52 msec (P < 0.05), and LA appendage from 225 +/- 55 msec to 245 +/- 48 msec (P < 0.05). Pilsicainide significantly prolonged the conduction time from the distal PV to PV-LA junction from 45 +/- 14 msec to 70 +/- 26 msec (P < 0.0001). In 3 of 5 patients who experienced AF termination with pilsicainide, PV-LA conduction block was observed just before AF termination. CONCLUSIONS: Pilsicainide can modify ERP heterogeneity and conduction properties in the PV and at the PV-LA junction. Because the PV and PV-LA junction have important roles as substrates for AF maintenance, pilsicainide may terminate AF by pharmacologic PV isolation.

Atrial Fibrillation↗

PubMed2004

Development of single-domain recombinant antibodies to reverse transcriptase domain of human hTERT.

This paper describes the development of single-domain recombinant antibodies against human telomerase core protein. A His-tagged hTERT spanning main reverse-transcriptase domain of hTERT was purified from host E. coli and used to immunize BALB/c mice. The VHs (heavy chain variable region genes) were amplified by PCR from total RNA of splenocytes and further induced random mutagenesis by DNA shuffling to enrich the repertoire of VH library. All VHs were cloned into phagemid vectors and displayed to generate 4 x 10(10) phage libraries. The candidates carrying VH domains against hTERT were primarily screened through three times of panning procedure on His-tagged hTERT coated microplates, and specific antibodies were further selected by West-Western blot. Two clones, designated as a3 and b8, were confirmed to interact with the target in the solid-phase assay. DNA sequencing proved their mouse VH origin. The purified single-domain antibody of b8 could not only recognize native hTERT, but also neutralize human telomerase activity on inhibitory assay and b8 showed the stronger suppressive efficacy compared with a3. The data demonstrated that the developed single-domain recombinant antibodies were hTERT-specific with high potential of binding and activity inhibition.

Amino Acid Sequence↗

PubMed2004

DNA damaging effects of sulfur dioxide derivatives in cells from various organs of mice.

The DNA-damaging effects of sulfur dioxide (SO2) derivatives (a mixture of sodium sulfite and sodium bisulfite, 3:1 M/M) in the cells of various organs (brain, lung, heart, liver, stomach, spleen, thymus, bone marrow and kidney) of male mice were studied using the single cell gel electrophoresis technique (SCGE). Three groups of six mice each received an i.p. dose of SO2 derivatives (125, 250 or 500 mg/kg body wt) daily for 7 days. A control group of six mice received 200 microl of normal saline i.p. daily for 7 days. Our results show that SO2 derivatives caused significant increases in olive tail moment (OTM) in cells from all organs tested in a dose-dependent manner. These results show that SO2 derivatives can cause DNA damage to multiple organs of mice and that SO2 derivatives are systemic DNA-damaging agents, not only to the respiratory system. It is suggested that SO2 derivative exposure has a potential risk to DNA in multiple organs of mammals and might be related to carcinogenesis or other diseases related to DNA damage. Further work is required to understand the toxicological role of SO2 and its derivatives on multiple or even all organs in humans and animals. Recent research results have shown that SO2 and its derivatives can also induce an increase in the frequencies of chromosomal aberrations, sister chromatid exchanges and micronuclei in mammalian cells and cause oxidative damage in multiple organs of male and female mice. Taken together, these results suggest that SO2 and its derivatives are systemic toxic agents. However, further studies need to be performed before a definitive conclusion can be drawn.

Animals↗

PubMed2004

An efficient and effective region-based image retrieval framework.

An image retrieval framework that integrates efficient region-based representation in terms of storage and complexity and effective on-line learning capability is proposed. The framework consists of methods for region-based image representation and comparison, indexing using modified inverted files, relevance feedback, and learning region weighting. By exploiting a vector quantization method, both compact and sparse (vector) region-based image representations are achieved. Using the compact representation, an indexing scheme similar to the inverted file technology and an image similarity measure based on Earth Mover's Distance are presented. Moreover, the vector representation facilitates a weighted query point movement algorithm and the compact representation enables a classification-based algorithm for relevance feedback. Based on users' feedback information, a region weighting strategy is also introduced to optimally weight the regions and enable the system to self-improve. Experimental results on a database of 10,000 general-purposed images demonstrate the efficiency and effectiveness of the proposed framework.

Abstracting and Indexing↗

PubMed2004

Mutations of neuronal voltage-gated Na+ channel alpha 1 subunit gene SCN1A in core severe myoclonic epilepsy in infancy (SMEI) and in borderline SMEI (SMEB).

PURPOSE: Severe myoclonic epilepsy in infancy (SMEI) is a distinct epilepsy syndrome. Patients with borderline SMEI (SMEB) are a subgroup with clinical features similar to those of core SMEI but are not necessarily consistent with the accepted diagnostic criteria for core SMEI. The aim of this study was to delineate the genetic correlation between core SMEI and SMEB and to estimate the frequency of mutations in both phenotypes. METHODS: We examined 96 healthy volunteers and 58 unrelated individuals whose clinical features were consistent with either core SMEI (n = 31) or SMEB (n = 27). We screened for genetic abnormalities within exons and their flanking introns of the genes encoding major subunits of the Na+ channels (SCN1A, SCN2A, SCN1B, and SCN2B) by using a direct sequencing method. RESULTS: In both core SMEI and SMEB, various mutations of SCN1A including nonsense and missense mutations were identified, whereas no mutations of SCN2A, SCN1B, and SCN2B were found within the regions examined. All mutations were heterozygous and not found in 192 control chromosomes. Mutations were identified in 26 (44.8%) of the 58 individuals and were more frequent (p < 0.05) in core SMEI (19 of 31) than in SMEB (seven of 27), as assessed by the continuity-adjusted chi2 test. Mutations resulting in a molecular truncation were found only in core SMEI. Among the mutations, two missense mutations were found in both core SMEI and SMEB. CONCLUSIONS: Our findings confirm that SMEB is part of the SMEI spectrum and may expand the recognition of SMEI and suggest other responsible or modifying genes.

Amino Acid Sequence↗