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Biomedical subjects

Li Zhou

Publications and source records attributed to Li Zhou.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Intra-operative stereotactic accuracy of computer-assisted robot orthopaedic trauma surgery planning system].

OBJECTIVE: To investigate the feasibility and accuracy of the software computer-assisted robot orthopaedic trauma surgery planning system (CAOTS). METHODS: The software CAOTS was developed and used on 85 cases of stereotactic operation, 24 model bones, 21 cadaveric extremity bones, and 40 patients. 307 groups of directional targets in these cases were randomly sampled. The distribution of error sources for evaluating system performance was embodied using Monte-Carlo method in order to derive the theoretic guarantees for further optimizing and enhancing the system performance, then the software SPSS 2.0 was used to analyze the errors. RESULTS: The statistical area of deviation number was 0.0408 +/- 0.4578 mm, corresponding to the result by Monte-Carlo method. Punching succeeded at the first run for all 307 cases without wrong locking and other clinical complications. CONCLUSION: Accurate and reliable, CAOTS improves the intra-operative navigation techniques and facilitates the orthopedists to perform operation.

Cadaver↗
PubMed2006

[Effects of medical robot-assisted surgical navigation system in distal locking of femoral intramedullary nails: an experimental study].

OBJECTIVE: To investigate the effects of medical robot-assisted surgical navigation system based on fluoroscopic images in distal locking of femoral intramedullary nails. METHODS: Using a robot-assisted computer-guided system designed based on modularization and minimization that permitted C-arm alignment assistance and real-time navigation control, provided constant feedback without the need for radiologic updates, thus avoiding constant X-ray exposure. The C-arm was used to collect the orthotopic and lateral X-ray images into the computer so as to calculate the locations of the target points. Nails were locked into 5 plastic femurs (Swiss Sybone, 35 holes), 2 dry human femoral specimens (12 holes), and one leg of fresh human cadaver (6 holes). Radiographs were taken to confirm that screws were positioned correctly, and fluoroscopic time associated with the locking procedure was recorded. RESULTS: All distal holes were locked successfully. In 6 (11.1%) of the 53 holes the drill bit touched the canal of the locking hole, albeit with no damage to the nail. The fluoroscopy time of per screw was 1.83 +/- 0.31 seconds. CONCLUSION: The medical robot-assisted surgical navigation system enables the physicians to precisely navigate surgical instruments throughout the procedure using just a few computer-calibrated radiographic images. The total radiation time per procedure can be significantly reduced because additional X-ray exposure is not required for tool navigation. The idea of a robot-assisted surgical navigation system is practicable.

Bone Nails↗
PubMed2006

Identification of a novel C2 domain factor in ovaries of orange-spotted grouper (Epinephelus coioides).

Follicle consists of an oocyte and a lot of surrounding follicular cells, and significant interactions exist between the oocyte and the somatic cells. In this study, a novel cDNA has been screened from a subtractive cDNA library between tail bud embryos and blastula embryos in the protogynous hermaphrodite orange-spotted grouper (Epinephelus coioides). Its full-length cDNA is 821 bp, and has an ORF of 414 bp for encoding a peptide of 137 aa, which shows 38%, 37%, 33%, and 33% homology with 4 putative proteins screened from zebrafish (Danio rerio). Conserved domain search in NCBI reveals a single C2 domain existing in the C2 domain superfamily proteins, and has only 7 beta strands in comparison with 8 beta strands of C2 domains in other C2 domain superfamily proteins. Artificial sex reversal, RT-PCR analysis and Western blot detection demonstrated ovary-specific expression of the C2 domain factor, and therefore the novel gene was designated as E. coioides ovary-specific C2 domain factor, EcOC2 factor. Moreover, predominant expression of EcOC2 factor was further revealed in grouper mature ovary, and its strong immunofluorescence signals were located between granulosa cells and oocyte zona radiata in grouper mature follicles. The data indicate that the novel EcOC2 factor might be a main component that associates between granulosa cells and the oocyte during oocyte maturation, and might play significant roles in regulating oocyte maturation and ovulation. Further studies on its developmental behaviour and physiological functions will elucidate the interactions between oocyte and the surrounding somatic cells and the underlying molecular mechanisms.

Amino Acid Sequence↗
PubMed2006

Terminology model discovery using natural language processing and visualization techniques.

Medical terminologies are important for unambiguous encoding and exchange of clinical information. The traditional manual method of developing terminology models is time-consuming and limited in the number of phrases that a human developer can examine. In this paper, we present an automated method for developing medical terminology models based on natural language processing (NLP) and information visualization techniques. Surgical pathology reports were selected as the testing corpus for developing a pathology procedure terminology model. The use of a general NLP processor for the medical domain, MedLEE, provides an automated method for acquiring semantic structures from a free text corpus and sheds light on a new high-throughput method of medical terminology model development. The use of an information visualization technique supports the summarization and visualization of the large quantity of semantic structures generated from medical documents. We believe that a general method based on NLP and information visualization will facilitate the modeling of medical terminologies.

Automation↗
PubMed2006

Penile torsion repair by suturing tunica albuginea to the pubic periosteum.

PURPOSE: The aim of the study was to evaluate the effectiveness of a new technique to repair penile torsion in children. METHODS: Eighteen boys with penile torsion were evaluated in our department from 1989 to 2003. Eleven had associated hypospadias, 4 had chordee without hypospadias, and 3 had torsion only. The direction of rotation was counterclockwise in 16 cases and clockwise in 2 cases. Torsion was repaired in 6 patients by degloving the penis and reattaching the dartos and the skin (comparative group). In 11 patients (1 with prior repair), the torsion was corrected by suturing the lateral edge of the corpus cavernosum to the pubic periosteum (study group). Two patients were not treated. RESULT: Follow-up ranges from 6 months to 7 years. All of the 11 cases in the study group had satisfactory correction of the penile torsion. All of the urethroplasties for hypospadias were successful. In the comparative group, none of 6 patients had satisfactory correction of the rotation. CONCLUSION: The technique of degloving the penis and reattaching the skin cannot reliably correct penile torsion in our experience. Lateral suturing of tunica albuginea to the pubic periosteum to repair penile torsion appears to be a better technique.

Child↗
PubMed2006

[Detection of intracellular reactive oxygen species by flow cytometry in Pichia pastoris fermentation].

In Pichia pastoris fermentation, methanol was oxidized into carbon oxide and produced a byproduct H2 O2, one of the partially reduced forms of molecular oxygen known as reactive oxygen species (ROS) . ROS are highly damaging towards cellular constituents. Flow cytometry (FCM) is an excellent method that permits the rapid, optical analysis of individual cells and has many advantages over conventional cytometry. However, its use in detecting intracellular ROS levels during Pichia fermentation was rarely reported. In our work, by means of flow cytometry, two fluorescent dye 2', 7'-dichlorofluorescin diacetate (DCFH-DA) and propidium iodide (PI) were used to detect ROS. The effect of intracellular ROS on Pichia pastoris cells during fermentation was studied through the comparison between DCFH-DA/PI double-stained cells and PI single-stained cells. In this study, the loss of cell viability during fermentation was correlated with the accumulation of ROS. At the glycerol batch and fed-batch phase, little ROS was accumulated intracellularly and cell viability reached almost 100%. At the early methanol fed-batch phase, intracellular ROS accumulation took place but 98.5% cells still kept viable. At the later methanol fed-batch phase, 94.0% cells accumulated high ROS. As a result, some cells lost their viability because of the damage of ROS. 25.4% dead cells accumulated high ROS in the total 29.1% dead cells.

Bioreactors↗
PubMed2006

Different types of neural cell death in the cerebellum of the ataxia and male sterility (AMS) mutant mouse.

To investigate the mechanisms(s) of age-dependent atrophy of the cerebellum of the ataxia and male sterility (AMS) mouse at young age, the morphological changes were evaluated and the nature of neural cell death was examined. Dying Purkinje cells lacked characters of classical apoptosis except for light microscopic morphology, but their death was considered to be autonomous death triggered by the direct effect of ams mutation, because of the acute and near-complete disappearance and particular change of the cytoplasm. In contrast, in the granular layer, typical apoptotic bodies were recognized by electron microscopy, and substantial numbers of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end-labeling (TUNEL)-positive cells and activated caspase-3-positive cells were observed. Granule cell death was considered to be target-related apoptosis induced after post-synaptic Purkinje cell death, because the age-dependent changes in TUNEL-positive cell counts followed that of Purkinje cell loss and the peak value was still noted 1 week after total loss of Purkinje cells. These results indicate that both total and partial losses of Purkinje cells and granule cells, respectively, contributed to the atrophy of the AMS cerebellum. Furthermore, different types of neuronal death were recognized; the granule cell death was apoptotic while Purkinje cell death was different from that of classical apoptosis.

Age Factors↗
PubMed2006

All-trans retinoic acid inhibited angiotensin II-induced increase in cell growth and collagen secretion of neonatal cardiac fibroblasts.

AIM: To determine whether all-trans retinoic acid (atRA) acts to modulate angiotensin II (Ang II)-induced cardiac fibroblast cell growth and collagen secretion. METHODS: Cultured neonatal rat cardiac fibroblasts (CF) were used in the experiment. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect cell growth of the CF; and immunocytochemistry and Western blotting were used to measure the production and secretion of collagen and the expression of transforming growth factor-beta1 (TGF-beta1) by the CF. RESULTS: atRA (10(-7) to 10(-5) mol/L) inhibited the Ang II-induced increase in cell growth of CF (P<0.05). Ang II stimulated the secretion of collagen types I and III by the CF. This effect was blocked by AT(1) receptor antagonist losartan (10(-6) mol/L), but not by AT2 receptor antagonist PD123319 (up to 10(-6) mol/L). Exposure of CF to atRA (10(-5) mol/L) attenuated the Ang II-induced increase in the secretion of collagen types I and III (P<0.05). atRA (10(-5) mol/L) also blocked the Ang II-induced increase in the expression of TGF-beta1. CONCLUSION: atRA inhibits the Ang II-induced increase in cell growth and collagen secretion of neonatal rat CF. The effect of atRA is possibly mediated by lowering the TGF-beta1 level. These observations support the notion that atRA is a potential candidate for the prevention and therapy of cardiac remodeling.

Angiotensin II↗
PubMed2006

Regulation of RraA, a protein inhibitor of RNase E-mediated RNA decay.

The recently discovered RraA protein acts as an inhibitor of the essential endoribonuclease RNase E, and we demonstrated that ectopic expression of RraA affects the abundance of more than 700 transcripts in Escherichia coli (K. Lee, X. Zhan, J. Gao, J. Qiu, Y. Feng, R. Meganathan, S. N. Cohen, and G. Georgiou, Cell 114:623-634, 2003). We show that rraA is expressed from its own promoter, P(rraA), located in the menA-rraA intergenic region. Primer extension and lacZ fusion analysis revealed that transcription from P(rraA) is elevated upon entry into stationary phase in a sigma(s)-dependent manner. In addition, the stability of the rraA transcript is dependent on RNase E activity, suggesting the involvement of a feedback circuit in the regulation of the RraA level in E. coli.

Alkyl and Aryl Transferases↗
PubMed2006

Mitogen-activated protein kinase signaling, oxygen sensors and hypoxic induction of neurogenesis.

In the adult nervous system, neuronal subpopulations sustain a hierarchical pattern of selective vulnerability to hypoxia. Hypoxia also activates quiescent neural progenitor cells (NPCs) resulting in their amplification and subsequent differentiation into neurons and glia. Use of rat organotypic hippocampal cultures facilitates examination of early signaling events in response to hypoxia and reoxygenation that result in neurogenesis. Cultures were exposed to hypoxia for up to 6 h followed by reoxygenation. CA1 neurons showed focal nuclear condensation by 2 h of hypoxia, but CA2 and CA3 neurons were spared. JNKs and c-Jun reached peak activation by 4 h, returning to basal levels by 6 h. Expression of oxygen sensors, hemoxygenase 2 and HIF1, were elevated by 30 min and 2 h, respectively. By 24 h of reoxygenation, there was proliferation of nestin-positive NPCs. With U0126, an upstream inhibitor of ERK activation, BrdU labeling was markedly reduced immunohistochemically as well as PCNA protein expression, suggesting a role for ERKs in the proliferation response. Immunohistochemically, antinestin detected NPCs and on Western blots reached peak levels by 24-48 h of reoxygenation. Proliferation and differentiation of endogenous NPCs in the area of neuronal loss further suggests that mechanisms potentially exist in vitro for replacement with functional neurons.

Animals↗
PubMed2006

Characterization of PAF-AH Ib1 in NOD mice: PAF-AH may not be a candidate gene of the diabetes susceptibility Idd4.1 locus.

We recently mapped Idd4 to a 5.2 cM interval on chromosome 11 with two subloci, Idd4.1 and Idd4.2, in nonobese diabetic (NOD) mice. Based on the localization of platelet-activating factor acetylhydrolase Ib1 (PAF-AHIb1) and the decreased activity of PAF-AH in type 1 diabetes (T1D) patients, we hypothesized that PAF-AHIb1 in Idd4.1 is a candidate gene. The PAF-AHIb1 gene in NOD mice was cloned and sequenced, and its expression and function were studied. No polymorphisms were detected in PAF-AHIb1 cDNA between NOD and B6 mice. The expression of PAF-AH Ib1 at the mRNA and protein levels was found to be similar in different tissues between NOD and B6 mice. PAF-AH activity does not differ in the pancreatic islets or spleen between NOD and B6 mice. Our findings suggest that PAF-AH Ib1 may not be a diabetes-susceptibility gene in the Idd4.1 sublocus.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2006

Effects of azadirachtin on six inorganic cation distributions in Ostrinia furnacalis (G.).

Azadirachtin (Az), as a botanical insecticide, is relatively safe and biodegradable. It affects a wide variety of biological processes, including the reduction of feeding, suspension of molting, death of larvae and pupae, and sterility of emerged adults in a dose-dependent manner. However,the mode of action of this toxin remains obscure. By using ion chromatography, we analyzed changes in six inorganic cation (Li+, Na+, NH4+, K+, Mg2+, and Ca2+) distributions of the whole body and hemolymph in Ostrinia furnacalis (G.) after exposure to sublethal doses of Az. The results showed that Az dramatically interfered with Na+, NH4 +, K+, Mg2+, and Ca2+ distributions in hemolymph of O. furnacalis (G.) and concentrations of these five cations dramatically increased. However, in the whole body, the levels of K+, Mg2+, and Ca2+ significantly, decreased after exposure to Az, except that Na+ and NH4 + remained constant. Li+ was undetected in both the control and treated groups in the whole body and hemolymph. It is suggested that Az exerts its insecticidal effects on O. furnacalis (G.) by interfering with the inorganic cation distributions related to ion channels.

Ammonia↗
PubMed2006

Directional and direct cloning strategy for high-throughput generation of recombinant baculoviruses.

The baculovirus expression vector system (BEVS) has become one of the most widely used systems for routine protein expression. We have developed an improved strategy to clone foreign genes directionally and directly into the baculovirus genome vector via a one-step procedure to generate recombinant viruses in a week. In this work, we constructed a host strain Escherichia coli DH10BacHB1.1, which contains the modified baculovirus shuttle genome vector pHBMBacmid1.1 for the cloning vector. The treated PCR products of foreign genes were ligated with the Bsu36I-digested vector. Then Spodoptera frugiperda (Sf9) cells were transfected directly with the ligation mixture. Using this method, the DsRed fluorescence protein and mannanase genes have been cloned in the baculovirus genome and expressed in the Sf9 cells. This strategy not only provides a means for high-throughput construction of recombinant baculoviruses, but also offers an idea of constructing other large plasmids and DNA virus-based expression vectors.

Animals↗
PubMed2006

Breast-feeding and risk for childhood obesity: does maternal diabetes or obesity status matter?

OBJECTIVE: We sought to evaluate whether maternal diabetes or weight status attenuates a previously reported beneficial effect of breast-feeding on childhood obesity. RESEARCH DESIGN AND METHODS: Growing Up Today Study (GUTS) participants were offspring of women who participated in the Nurses' Health Study II. In the present study, 15,253 girls and boys (aged 9-14 years in 1996) were included. Maternal diabetes and weight status and infant feeding were obtained by maternal self-report. We defined maternal overweight as BMI > or = 25 kg/m2. Childhood obesity, from self-reported height and weight, was based on the Centers for Disease Control and Prevention definitions as normal, at risk for overweight, or overweight. Maternal status categories were nondiabetes/normal weight, nondiabetes/overweight, or diabetes. Logistic regression models used generalized estimating equations to account for nonindependence between siblings. RESULTS: For all subjects combined, breast-feeding was associated with reduced overweight (compared with normal weight) in childhood. Compared with exclusive use of formula, the odds ratio (OR) for exclusive breast-feeding was 0.66 (95% CI 0.53-0.82), adjusted for age, sex, and Tanner stage. Results did not differ according to maternal status (nondiabetes/normal weight OR 0.73 [95% CI 0.49-1.09]; nondiabetes/overweight 0.75 [0.57-0.99]; and diabetes 0.62 [0.24-1.60]). Further adjustment for potential confounders attenuated results, but results remained consistent across strata of maternal status (P value for interaction was 0.50). CONCLUSIONS: Breast-feeding was inversely associated with childhood obesity regardless of maternal diabetes status or weight status. These data provide support for all mothers to breast-feed their infants to reduce the risk for childhood overweight.

Adolescent↗
PubMed2006

[A digital subtraction angiography system based on LUT algorithms].

Look-up table (LUT) algorithms have been widely used in digital signal processing, but the article on the application of LUT algorithms in digital subtraction angiography was rarely reported. In this article, the effect of different LUT algorithms on digital subtraction angiography images is introduced. The result reveals that different LUT algorithms can bring about different effects of image. Based on analysis and comparison, we deem it possible to acquire improved images of DSA by use of some LUT algorithms with image processing.

Algorithms↗
PubMed2006

[Vertical distribution of soil organic carbon and total nitrogen in reed wetland].

With element analyzer, this paper measured the variation of organic carbon and total nitrogen in different soil depths of reed wetland. The results showed that soil organic carbon, total nitrogen, and C/N ratio were decreased gradually with increasing soil depth, and their accumulation peaks were differed with soil layers and months. Soil temperature and moisture and the growth status of reed were the main factors caused the differences. Soil organic carbon was strongly positively correlated with soil total nitrogen content in July, August and October, the R2 being 0.73, 0.73 and 0.71 respectively, but weakly correlated in September. Soil C/N ratio was negatively correlated to soil organic carbon and total nitrogen, but the correlativity was higher with soil total nitrogen than with soil organic carbon, suggesting that soil C/N ratio was more determined by the content of soil total nitrogen.

Carbon↗
PubMed2006

[Comparison of different clinical staging systems for hepatocellular carcinoma].

OBJECTIVE: To compare the prognostic efficacy of three clinical staging systems: the Chinese system (CS), CLIP scores, and TNM for hepatocellular carcinoma (HCC). METHODS: 107 cases diagnosed as HCC between January 2000 and October 2003 were retrospectively analyzed. Their clinical stages were decided on the basis of data in CLIP or Chinese staging system when the HCC diagnosis had been confirmed. Fifty-three of the 107 patients underwent surgical resection. The TNM stage was therefore determined according to surgico-pathological results. The survival of those patients with respective to different stages were analyzed and compared using Kaplan-Meier curves and Log rank method. RESULTS: All the patients were followed up after treatment. The 3-year survival rate in the CS Ia, Ib and CLIP 0 group were 100%. The 1- and 2-year survival rates of CS IIIa group was 68% and 51%, respectively. The 1-year survival in CS IIIb group was only 20.9%. The 1-, 2-, and 3-year survival rate in patients with a CLIP score beyond 4 was 57.1%, 49.9%, and 33.5%, respectively. In patients treated with surgical resection, the CS Ia group and TNM I group had a 3-year survival rate of 100%. The 1- and 3-year survival rate in CS IIb were 83.3% and 75.0%, in TNM III group 93.7% and 77.5%. CONCLUSION: The CLIP system may provide accurate prediction of prognosis based on early clinical features. The CS system is comparably efficient in predicting the prognosis of HCC patients, particularly in patients with severe cirrhosis.

Adolescent↗