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Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 289 records · Page 16Linked to original sources
PubMed2005

An investigation of the prevalence of depressive symptoms in soldiers during military training.

OBJECTIVES: A cross-sectional study was conducted to determine the prevalence of depressive symptoms in soldiers during military training in Chinese army and to identify associations between depressive symptoms and socio-demographic characteristics. METHODS: The self-rating depression scale (SDS) was used to assess self-reported experiences of depression among 1107 young adult males during military training. The following socio-demographic variables are considered as independent variables: age, service time, settlement type, education, levels of family income, family type, education of parents, health status, history of negative accidents, social support status and hobby status. A logistic regression model was used to estimate the association of these variables with depressive symptoms. RESULTS: 25.20% (n = 279) of the servicemen had depressive symptoms. The soldiers who had high education level (OR = 1.74; 95%CI: 1.37-2.12), come from city or town (OR = 1.39; 95%CI: 1.18-1.61), have served in army for a shorter time (OR = 1.63; 95%CI: 1.43-1.88), had head ache during training course (OR = 1.39; 95%CI: 1.12-2.09), had abdomen ache or diarrhea during training course (OR = 1.85; 95%CI: 1.47-2.13) and had training injury during training course (OR = 1.67; 95%CI: 1.29-1.83) are associated with depressive symptoms. CONCLUSIONS: There was a high prevalence rate of depressive symptoms among soldiers during military training. Special attention should be paid to avoiding depressive symptoms in those who have high education level, come from city or town, have served in army for a shorter time and have health problems during training course.

Adolescent↗
PubMed2005

Preliminary DNA identification for the tsunami victims in Thailand.

The 2004 Southeast Asia Tsunami killed nearly 5,400 people in Southern Thailand, including foreign tourists and local residents. To recover DNA evidence as much as possible from the seriously decomposed bodies, we explored procedures of sample preparation from both bone and tooth samples as well as both mitochondrial and nuclear markers. Despite having failed to recover enough DNA for nuclear marker typing, we succeeded in obtaining fully informative results for mitochondrial markers (HV1 and HV2) from 258 tooth samples with a success rate of 51% (258/507). Using an organic DNA extraction method coupled with an ultrafiltration step, we obtained 16 STR (including 13 CODIS loci, one sex discrimination locus, and two Identifiler loci) profiles for 834 samples with a success rate of 79% (834/1,062). In addition, by comparing the allelic frequencies between the typed samples as a group and other index populations, we conclude that the Thai tsunami victims are a combined group of several populations. Our results provide valuable evidence and protocols for the future forensic practice.

Bone and Bones↗
PubMed2005

HIV-related stigma among market workers in China.

HIV-related stigma was examined among 209 employees and owners of stalls in 5 markets in an eastern coastal city in China. Of the participants 53% were women and 47% were men; 100% were Han. Ages ranged from 18 to 49 years (M=35, SD=8.1). Half of the participants believed that punishment was an appropriate response toward those living with HIV (50%). Over half (56%) were unwilling to be friends with infected individuals. The majority thought that those living with HIV should be isolated (73%). They agreed that persons living with HIV should not take care of other people's children (85%). Punishing beliefs toward persons living with HIV were related to being male, older, married, less educated, and unwilling to be tested for HIV.

Adolescent↗
PubMed2005

Determination of critical parameters among elite female shot putters.

The aim of this study was to determine if critical parameters for elite performance could be identified among a population of female shot putters. The performance of seven of the top women shot putters competing at the 2002 USA National Championships was examined. Video data were captured using two Panasonic 60 Hz cameras and the best throws of each athlete were digitized and analyzed using a Peak Motus three-dimensional motion analysis system. Thirty variables were examined for their effect on the distance of the throw. Correlation analysis indicated that measured distance was positively correlated with release speed (r = 0.97, p < 0.0003) and shoulder-hip separation (r = 0.72, p < 0.06) and negatively correlated with release angle (r = -0.74, p < 0.056), rear knee angle at rear foot touchdown (r = -0.93, p < 0.003) and rear knee angle at release (r = -0.76, p < 0.047). Greater knee flexion angle at both rear foot touch down and release along with a neutral shoulder-hip angle at release were identified as the most critical parameters for success among this sample of elite women shot putters. The unique observation about the knee positions at specific events should assist in new training and coaching developments.

Biomechanical Phenomena↗
PubMed2005

Identification of Mycobacterium species by secA1 sequences.

We describe a novel molecular method for the differentiation and identification of 29 mycobacterial species. The target is the secA1 gene that codes for the essential protein SecA1, a key component of the major pathway of protein secretion across the cytoplasmic membrane. A 700-bp region of the secA1 gene was amplified and sequenced from 47 American Type Culture Collection strains of 29 Mycobacterium species as well as from 59 clinical isolates. Sequence variability in the amplified segment of the secA1 gene allowed the differentiation of all species except for the members of the Mycobacterium tuberculosis (MTB) complex, which had identical sequences. A range of 83.3 to 100% interspecies similarity was observed. All species could also be differentiated by their amino acid sequences as deduced from the sequenced region of the secA1 gene, with the exception of the MTB complex. Partial sequences of secA1 from clinical isolates belonging to nine frequently isolated species of mycobacteria revealed a very high intraspecies similarity at the DNA level (typically >99%; range, 96.0 to 100%); all clinical isolates were correctly identified. Comparison of the deduced 233-amino-acid sequences among clinical isolates of the same species showed between 99.6 and 100% similarity. To our knowledge, this is the first time a secretion-related gene has been used for the identification of the species within a bacterial genus.

Adenosine Triphosphatases↗
PubMed2005

Comparison of methods for detection of vaccinia virus in patient specimens.

We analyzed a shell vial culture assay (SVA), real-time PCR, and a direct fluorescent antibody assay (DFA) for rapid detection of vaccinia virus from vaccination sites of Dryvax vaccine recipients. Of 47 samples assayed, 100% were positive by PCR, 89% were positive by SVA, and 40% were positive by DFA. DFA was limited by the need for adequate numbers of cells, with 32% of samples inadequate for interpretation. DFA performed better with specimens from patients who had not previously received the vaccine. PCR was positive for longer times postvaccination than was SVA. Infectious virus could be recovered after 45 min of acetone fixation of shell vial coverslips. Commercially available polyclonal antibodies cross-reacted with other orthopoxviruses and herpes simplex 1, but commercially available monoclonal antibodies were specific for vaccinia virus. In summary, PCR was the most sensitive test for detecting vaccinia virus in clinical specimens, while the DFA was the most rapid but the least sensitive test.

Animals↗
PubMed2005

Characterization of growth and differentiation in a telomerase-immortalized human corneal epithelial cell line.

PURPOSE: To develop and characterize a telomerase-immortalized human corneal epithelial cell line (hTCEpi) to serve as an in vitro model for studying the molecular mechanisms involved in regulating human corneal epithelial cell differentiation. METHODS: Primary cultures of human corneal epithelial cells were infected with a retroviral vector encoding human telomerase reverse transcriptase (hTERT). Infected hTCEpi cells were selected, cloned, and characterized to identify telomerase activity, proliferative capacity, karyotype, and differentiative potential in routine culture and under consecutive submerged and air-lifted conditions. Cells were evaluated to measure cell cycle kinetics (anti-Ki-67, anti-p16), stratification (phalloidin and anti-ZO-1), and differentiation (anti-K3, anti-BCL-2 and TUNEL labeling). RESULTS: hTCEpi cells exhibited telomerase activity, a normal karyotype and cell cycle kinetics at greater than 240 population doublings, and loss of p16 after passage 10. Air-lifting produced a well stratified epithelium (five to seven cell layers) with apical ZO-1-stained tight junctions. Submersed culture demonstrated increasing expression of stratification markers (K5/K14) with K3-corneal keratin marker expression in long-term, air-lifted culture. Anti-BCL-2 staining showed both nuclear and cytoplasmic localization with loss of nuclear BCL-2 expression in TUNEL-labeled surface epithelial cells. CONCLUSIONS: hTCEpi cells stratify, differentiate, and desquamate similar to normal human corneal epithelium. Further study of the hTCEpi cell line may be valuable in studying the molecular mechanisms regulating corneal epithelial cell differentiation and desquamation.

Blotting, Western↗
PubMed2005

High dose chemotherapy and transplantation of hematopoietic progenitors from murine D3 embryonic stem cells.

Differentiating embryonic stem (ES) cells are an increasingly important source of hematopoietic progenitors, useful for both basic research and clinical applications. To date, characteristics of specific factors capable of influencing hematopoietic cell fate from ES cells remains elusive. We report that mMSC Feeder Layer and the combination of VEGF, SCF and TPO strongly promote hematopoietic differentiation. The results showed that the cells induced from ES-D3 expressed hematopoietic progenitor antigens (CD34 and CD117), myelocyte cell antigen (CD11b), erythrocyte cell antigen (Ter119), and transcription factors (Flk-1, GATA-2, SCL, beta-H1 and beta-major). Furthermore, those induced differentiated cells were injected into female C57BL/6 mice which were treated with high dose topotecan chemotherapy to restore part of their blood system function. We observed rapid white blood cell recovery, which suggested that the infusion of differentiated cells has a positive impact on hematopoiesis. The Sry gene in peripheral blood, bone marrow and spleen of transplanted female mice was confirmed by PCR analysis, which affirmed the existence of the chimera.

Animals↗
PubMed2005

A web-based system for managing and co-ordinating multiple multisite studies.

Efficient and secure collection and management of information is essential in any modern biomedical study. Data management and coordination of multisite studies is a complex process. It involves development of systems for data collection, data cleaning with quality assurance checks, and specimen tracking, as well as development of procedures for conducting the study, training clinical sites, and communicating with sites to answer study questions and resolve and track data inquiries and resolutions. We developed a secure web-based system that is designed to automate evaluation of eligibility criteria and data collection, track specimens, serve as a resource for study-specific information, facilitate communication across sites in multisite studies, track data queries and resolutions, and allow administrative management of studies. The system combines a common framework across studies that defines the internal structure for all the web pages, with a study-specific one that defines the content of each page via a relational database. This combination creates a flexible and efficient environment enabling several multisite studies to be simultaneously or consecutively implemented and managed in a timely manner. We describe the development process, the system and its evaluation, current status, lessons learned, and future development plans.

Biomarkers, Tumor↗
PubMed2005

Hamstring muscle kinematics during treadmill sprinting.

INTRODUCTION/PURPOSE: The objective of this study was to characterize hamstring muscle kinematics during sprinting, so as to provide scientific data to better understand injury mechanisms and differences in injury rates between muscles. METHODS: We conducted three-dimensional motion analyses of 14 athletes performing treadmill sprinting at speeds ranging from 80 to 100% of maximum. Scaled musculoskeletal models were used to estimate hamstring muscle-tendon lengths throughout the sprinting gait cycle for each speed. We tested the hypothesis that the biceps femoris (BF) long head would be stretched a greater amount, relative to its length in an upright posture, than the semitendinosus (ST) and semimembranosus (SM). We also tested the hypothesis that increasing from submaximal to maximal sprinting speed would both increase the magnitude and delay the occurrence of peak muscle-tendon length in the gait cycle. RESULTS: Maximum hamstring lengths occurred during the late swing phase of sprinting and were an average of 7.4% (SM), 8.1% (ST), and 9.5% (BF) greater than the respective muscle-tendon lengths in an upright configuration. Peak lengths were significantly larger in the BF than the ST and SM (P < 0.01), occurred significantly later in the gait cycle at the maximal speed (P < 0.01), but did not increase significantly with speed. Differences in the hip extension and knee flexion moment arms between the biarticular hamstrings account for the intermuscle variations in the peak lengths that were estimated. CONCLUSIONS: We conclude that intermuscle differences in hamstring moment arms about the hip and knee may be a factor contributing to the greater propensity for hamstring strain injuries to occur in the BF muscle.

Adolescent↗
PubMed2005

Functional analysis of a reproductive organ predominant expressing promoter in cotton plants.

Transgenic Bt insect-resistant cotton plants have high insect resistance in the early stage of development, but relatively low resistance in the late stage. Substituting a reproductive organ-specific promoter for the CaMV35S promoter presently being used could be an ideal solution. For the first time, the promoter sequence of ADP-ribosylation factor 1 (arf1) gene was isolated from Gossypium hirsutumY18 by means of inverse PCR. The sequencing result discovered the unique structure of the arf1 promoter, including four promoter-specific elements, the initiator, TATA box, CAAT box and GC box, and also an intron in 5'-untranslation region. Four plant expression vectors were constructed for functional analysis of the promoter. Based on the pBl121 plant expression vector, four truncated arf1 promoters took the place of the CaMV35S promoter. These vectors were different only in their promoter regions. They were introduced into cotton plants via pollen tube pathway. Histochemical GUS staining and fluorescence quantitative analyses were performed to examine the expression patterns of the GUS gene driven by the 4 arf1 truncated promoters in transgenic cotton plants respectively. The results showed that the arf1 promoter was a typical reproductive organ-specific promoter. Hopefully, the arf1 promoter can be a regulatory element for designing cotton reproductive organs with desired characteristics.

ADP-Ribosylation Factor 1↗
PubMed2005

Intrinsic fluorescent detection of tau conformation and aggregation.

The polymerization of the microtubule-associated protein tau into paired helical filaments (PHFs) is one of the hallmarks of Alzheimer's disease. Insights into the prerequisites and kinetics of the polymerization was obtained by the in vitro analysis of this process. In the past, fluorescent dyes were used to stain amyloidogenic material in histology and later on similar dyes were used in in vitro studies as well. To circumvent the flaws of extragenous dyes, namely the alteration of the polymerization kinetic or incompatibility with other chemical compounds needed for stability analysis, we applied tryptophan fluorescence to the in vitro analysis of PHF formation. Single tryptophans were introduced into the hexapeptide PHF6 within the third repeat, which was shown to be involved in beta sheet formation and scattered around the whole microtubule binding domain. Tryptophan fluorescence was then used to scan the microtubule binding domain for accessibility to quenching reagent in the soluble and the aggregated state and the fluorescence resonance energy transfer (FRET) between tryptophan and tyrosine 310. Furthermore, this approach enables the analysis of stability of PHFs in the presence of Guanidinium hydrochloride. The examples given here could be applied in modified ways to other amyloidogenic proteins.

Fluorescence Resonance Energy Transfer↗
PubMed2005

Successive chromosome walking by compatible ends ligation inverse PCR.

Here we describe an advanced polymerase chain reaction (PCR) technique, the compatible ends ligation inverse PCR (CELI-PCR) for chromosome walking. In CELI-PCR, several restriction enzymes, which produce compatible cohesive ends, were used to digest target DNA simultaneously or sequentially to produce DNA fragments of suitable size. DNA fragments were then easily circularized and PCR amplification could be carried out efficiently. The previous limitations of inverse PCR were overcome, such as unavailable restriction sites, poor template DNA circularization, and low amplification efficiency. Therefore, successive chromosome walking was performed successfully. Our work, isolating a 11,395-bp fragment from Gossypium hirsutum, was presented as an example to describe how CELI-PCR was carried out.

Chromosome Walking↗
PubMed2005

An integrated approach utilizing proteomics and bioinformatics to detect ovarian cancer.

OBJECTIVE: To find new potential biomarkers and establish the patterns for the detection of ovarian cancer. METHODS: Sixty one serum samples including 32 ovarian cancer patients and 29 healthy people were detected by surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS). The protein fingerprint data were analyzed by bioinformatics tools. Ten folds cross-validation support vector machine (SVM) was used to establish the diagnostic pattern. RESULTS: Five potential biomarkers were found (2085 Da, 5881 Da, 7564 Da, 9422 Da, 6044 Da), combined with which the diagnostic pattern separated the ovarian cancer from the healthy samples with a sensitivity of 96.7%, a specificity of 96.7% and a positive predictive value of 96.7%. CONCLUSIONS: The combination of SELDI with bioinformatics tools could find new biomarkers and establish patterns with high sensitivity and specificity for the detection of ovarian cancer.

Adolescent↗
PubMed2005

Single nucleotide polymorphisms in K(ATP) channels: muscular impact on type 2 diabetes.

ATP-sensitive K+ channels (K(ATP) channels) play an important role in glucose homeostasis. A single nucleotide polymorphism (SNP) in the Kir6.2 subunit causes a point mutation of Glu23 to lysine and reduces the ATP sensitivity of pancreatic K(ATP) channels. The SNP found in 58% of Caucasians accounts for 15% of type 2 diabetes. Here we show evidence for dysregulations of muscular K(ATP) channels with the E23K variation. We were particularly interested in the channel modulation by intracellular protons, as pH changes widely and frequently in skeletal muscles. Surprisingly, we found that the defect of the E23K variant was more related to pH than ATP. A level of intracellular acidification seen during exercise not only activated the E23K channel more readily than the wild type, but also relieved the channel inhibition by ATP, leading to a vast increase in the channel open-state probability by approximately sevenfold at pH 6.8 over the wild-type channel at pH 7.4. Considering the reduction in sarcolemmal excitability, muscle fatigue, and impairment of muscular glucose uptake found previously by genetically disrupting K(ATP) channels, it is likely that the E23K variant in muscular K(ATP) channels affects systemic glucose homeostasis and poses an important risk factor for type 2 diabetes and obesity.

Amino Acid Substitution↗
PubMed2005

Effects of acupuncture on nNOS and iNOS expression in the rostral ventrolateral medulla of stress-induced hypertensive rats.

This study was to observe the changes of the neuronal and inducible nitric oxide synthase (nNOS & iNOS) as well as their mRNAs in the rostral ventrolateral medulla (RVLM) of stress-induced hypertensive rats before and after acupuncture, and thereby to infer the curative mechanism of acupuncture on hypertension. The result indicated that the systolic blood pressure (SBP) of stress group rats was increased significantly (P < 0.01), it was accompanied that the expression of nNOS in the RVLM, including the immunoreactive neuron number (P < 0.05), the optical density (OD) (P < 0.01), and the mRNA (P < 0.01) were obviously elevated, while those of iNOS (P < 0.05, P < 0.01 and P < 0.01) were evidently lowered in the stress-induced hypertensive rats. Electroacupuncture (EA) points at "Zusanli" (St. 36) and "Lanwei" (Extra 37) on the same hindlimb were stimulated by an EA apparatus (Type G6805-2) with dense sparse wave (4-20Hz) and 4mA intensity. EA application could return the SBP (P < 0.05), and the changes on the expression of both nNOS and iNOS (P < 0.05, P < 0.01 and P < 0.01). These results suggest that the curative mechanism of acupuncture on stress-induced hypertension is related to the changes of nNOS and iNOS in the RVLM of rats.

Acupuncture Therapy↗
PubMed2005

[Mycophenolic acid induced apoptosis in T lymphocytic cells Molt-4 and its mechanism].

OBJECTIVE: To determine whether mycophenolic acid (MPA) exerts an apoptotic effect on human leukemic T cells Molt-4 and to elucidate its possible mechanism. METHODS: Cell morphology, DNA fragmentation, cell cycle,percentage of annexin V positive cells and enzymatic activity of caspase-3 were measured by microscopic, electrophoretic and flow cytometric techniques respectively. Human leukemic B cell line Raji was used as control. RESULT: MPA could induce apoptosis of Molt-4 cells with dose-and time-dependent manners; cells were blocked in the S phase. The activity of caspase-3 was enhanced in a dose-dependent manner in Molt-4 cells treated with MPA for 24 h. MPA could not induce apoptosis in Raji cells. CONCLUSION: MPA can induce apoptosis in Molt-4 cells which may be involved in the activation of caspase-3.

Antibiotics, Antineoplastic↗