Biomedical subjects

B Li

Publications and source records attributed to B Li.

At least 253 records · Page 14Linked to original sources

PubMed2000

Binding of the maize cytosolic Hsp70 to calmodulin, and identification of calmodulin-binding site in Hsp70.

Using a gel-overlay technique of biotinylated calmodulin (CaM), we showed that maize cytosolic Hsp70 protein could bind to CaM in the presence of 1 mM CaCl2. The purified maize cytosolic Hsp70 inhibited the activity of CaM-dependent NADK in a concentration-dependent manner. A synthetic peptide, which possesses the 21 amino acid sequence, PRALRRLRTACERAKRTLSST, at positions 261-281 in maize cytosolic Hsp70, could associate with CaM in the presence of 1 mM calcium. The synthetic peptide inhibited CaM-dependent NADK activity and PDE activity. This indicates that the 21-amino acid sequence at positions 261-281 is the CaM-binding site. The binding of CaM to Hsp70 inhibited the ATPase activity of Hsp70. The possible regulator function of Hsp70 in cell signaling events in response to heat stress is discussed.

Amino Acid Sequence↗

PubMed2000

Longitudinal analysis of development among single and nonsingle children in Nanjing, China: ten-year follow-up study.

In order to examine the impact of "one-child-per-couple" family planning policy on child development, a longitudinal study of a group of children in Nanjing, China, was carried out between 1984 and 1995. The same cohort of children was examined at four stages of development: preschool, early school, preadolescence, and adolescence. Achenbach's Child Behavior Checklist was used to measure the child's behavior. A total of 274 children were surveyed in all four stages. The total behavior problem scores obtained at different stages of development were compared among boys and girls. The results showed that the total score declined significantly in association with the time. As the child grew older, the problems score decreased significantly. This maturation effect was seen for both boys and girls. On average, boys' scores dropped from 21 to 11, whereas girls' scores went from 19.5 to 12. In comparing single with nonsingle boys, there were no significant differences throughout the four stages of development. However, girls who were single children, in contrast to girls with siblings, had significantly higher scores of total behavior problems at each stage of development. These findings illustrate that the longitudinal effect of being a "single-child" is similar to other studies, indicating a minimal impact of family policy. However, the effects were more prominent among girls. This phenomenon can be explained by parents' different attitude toward single-children because of gender difference.

Adolescent↗

PubMed2000

Heat conduction in one-dimensional nonintegrable systems

Two classes of one-dimensional nonintegrable systems represented by the Fermi-Pasta-Ulam (FPU) model and the discrete straight phi(4) model are studied to seek a generic mechanism of energy transport on a microscopic level sustaining macroscopic behaviors. The results enable us to understand why the class represented by the straight phi(4) model has a normal thermal conductivity and the class represented by the FPU model does not even though the temperature gradient can be established.

Journal Article↗

PubMed2000

A novel approach to extract colon lumen from CT images for virtual colonoscopy.

An automatic method has been developed for segmentation of abdominal computed tomography (CT) images for virtual colonoscopy obtained after a bowel preparation of a low-residue diet with ingested contrast solutions to enhance the image intensities of residual colonic materials. Removal of the enhanced materials was performed electronically by a computer algorithm. The method is a multistage approach that employs a modified self-adaptive on-line vector quantization technique for a low-level image classification and utilizes a region-growing strategy for a high-level feature extraction. The low-level classification labels each voxel based on statistical analysis of its three-dimensional intensity vectors consisting of nearby voxels. The high-level processing extracts the labeled stool, fluid and air voxels within the colon, and eliminates bone and lung voxels which have similar image intensities as the enhanced materials and air, but are physically separated from the colon. This method was evaluated by volunteer studies based on both objective and subjective criteria. The validation demonstrated that the method has a high reproducibility and repeatability and a small error due to partial volume effect. As a result of this electronic colon cleansing, routine physical bowel cleansing prior to virtual colonoscopy may not be necessary.

Adult↗

PubMed2000

A quantitative genetic model for analyzing species differences in outcrossing species.

A genetic model based on a two-level intra- and interspecific mating design is proposed to estimate the genetic architecture of species differences and heterosis for outcrossing species. The underlying genetic analyses make use of classical quantitative genetic theories and recent results from molecular genetic studies. Gene effects across different quantitative trait loci (QTL) can be approximated by a geometric series. Under natural selection, gene effects are often associated with allele frequencies in a particular way, which can be approximated by the gamma distribution. By incorporating these approximations into family structural analyses in the mating design, we are able to estimate a number of genetic parameters that contribute to quantitative genetic variation based on a nonlinear optimization approach. These parameters include the number of QTL, their gene effects, and their allele frequencies in the parental populations. We perform simulation studies and illustrate an example to demonstrate the statistical property and procedure of the method.

Alleles↗

PubMed2000

Effects of T'ai Chi training on function and quality of life indicators in older adults with osteoarthritis.

OBJECTIVE: To determine the effects of T'ai Chi training on arthritis self-efficacy, quality of life indicators, and lower extremity functional mobility in older adults with osteoarthritis. DESIGN: A prospective, randomized, controlled clinical trial. Intervention length was 12 weeks, with outcomes measured before and after intervention using blinded testers. Group (T'ai Chi vs Control) x time (2 x 2) mixed factorial ANOVA. SETTING: Allied Health Sciences Center at Springfield College, Springfield, MA PARTICIPANTS: A total of 33 community-dwelling participants (mean age 68) diagnosed with lower extremity osteoarthritis and having no prior T'ai Chi training longer than 2 weeks. INTERVENTION: T'ai Chi training included two 1-hour T'ai Chi classes per week for 12 weeks. MEASUREMENTS: Arthritis self-efficacy (Arthritis Self-Efficacy Scale), quality of life indicators (Arthritis Impact Measurement Scale), functional outcomes (one-leg standing balance, 50-foot walking speed, time to rise from a chair). RESULTS: T'ai Chi participants experienced significant (P < .05) improvements in self-efficacy for arthritis symptoms, total arthritis self-efficacy, level of tension, and satisfaction with general health status. CONCLUSIONS: A moderate T'ai Chi intervention can enhance arthritis self-efficacy, quality of life, and functional mobility among older adults with osteoarthritis. T'ai Chi training is a safe and effective complementary therapy in the medical management of lower extremity osteoarthritis.

Activities of Daily Living↗

PubMed2000

A missense mutation G2320R in the thyroglobulin gene causes non-goitrous congenital primary hypothyroidism in the WIC-rdw rat.

A convincing line of evidence is being developed that the congenital nongoitrous hypothyroidism and dwarfism observed in the WIC-rdw rat may indeed be caused by a primary defect in thyroid hormonogenesis. In support of this hypothesis, several recent reports have shown the presence of elevated molecular chaperone levels in the WIC-rdw thyrocytes, the endoplasmic reticulum of which was markedly dilated, suggesting a defect in intracellular protein transport. Here the studies were undertaken to identify the precise molecular defect in the WIC-rdw rat. First, the genetic linkage analysis revealed that the rdw locus was on rat chromosome 7 and was identical to the thyroglobulin (Tg) gene locus. Moreover, the Tg protein level was reduced in the WIC-rdw thyroid despite a similar level of the Tg gene transcripts that were indistinguishable in their size from the normal. Next, the complete sequencing of the rdw and the normal rat Tg cDNAs revealed a single nucleotide change, G6958C, resulting in a G2320R missense mutation in a highly conserved region of the Tg molecule. Finally, transient expression of the intact Tg cDNA containing the rdw mutation in the COS-7 cells showed no detectable Tg in the secreted media, indicating a severe defect in the export of the mutant Tg. Together, our observations suggest that a missense mutation, G2320R, in the Tg gene is responsible for the rdw mutation in the WIC-rdw rat.

Animals↗

PubMed2000

Comparison of two kinds of methods to determine the titer of recombinant retrovirus containing beta-globin gene based on G418 selection.

Four recombinant retrovirus (RV) vectors containing human beta-globin gene and regulatory elements were constructed. To determine the titers of recombinant RV from corresponding producer cell lines, we compared two kinds of method (the simple and the conventional) based on G418 resistance, which is conferred by neo gene of RV vector. The results demonstrated that the simple method shortened the selection period to 3 d instead of 10-12 d with the conventional method and reduced the amount of work; importantly, the titers determined by the simple method were not different significantly from those measured by the conventional method. It can be concluded that the simple method can be used to determine the titers of recombinant RV containing not only cDNA but also genomic DNA with introns and complex regulatory elements instead of the conventional method.

3T3 Cells↗

PubMed2000

Telomerase activity in preleukemia and acute myelogenous leukemia.

The development of acute leukemia from preleukemia involves the appearance of clones with increasing proliferative potential. The studies described here demonstrate that telomerase activity progressively increases as the bone marrow cells acquire increasing proliferative potential. This was demonstrated by measuring telomerase activity in normal bone marrow, in post-treatment lymphoma marrows with skewed Lyonization, and in MDS and AML marrows. The greater telomerase activity in myelodysplastic marrow than in normal marrow is not due to a higher proportion of blast cells or to a higher proliferative rate of the MDS marrow. These data demonstrate that the increasing proliferative potential of the marrow which occurs during the development of AML is associated with a simultaneous increase in telomerase activity.

Adolescent↗

PubMed2000

Suppression of telomerase activity and cytokine messenger RNA levels in acute myelogenous leukemia cells in vivo in patients by amifostine and interleukin 4.

High levels of telomerase activity and high rates of cell proliferation are associated with a poor prognosis in acute myelogenous leukemia. Furthermore, cytokine production by leukemia cells is believed to play an important role in determining the proliferative characteristics of leukemia. The in vivo effects of two noncytotoxic agents on these parameters were determined in 33 acute myelogenous leukemia patients. Three daily doses of interleukin (IL) 4 or a single dose of amifostine reduced telomerase activity in the leukemia marrow cells in 7 of 9 and 11 of 13 patients, respectively. The administration of a single dose of amifostine resulted in a reduction in tumor necrosis factor alpha and IL-6 transcript levels in the marrow cells of 10 of 13 and 12 of 13 patients in which these transcripts were present. The administration of only three doses of IL-4 or a single dose of amifostine has a significant effect on leukemia cell parameters, which are believed to have a significant impact on the in vivo biology of the disease and on its response to remission induction therapy.

Adult↗

PubMed2000

A survey on knowledge and skills in the early diagnosis of leprosy in general health services at different levels in Shandong Province, The People's Republic of China.

In the late phase of a leprosy control programme, problems arise with regard to the early detection and treatment of a small number of new incident cases. We describe a study in the province of Shandong, People's Republic of China, on the knowledge and skills regarding leprosy of general health service staff, including rural doctors, paramedical doctors at township level, doctors from county general and provincial hospitals and dermatologists. The results showed that there is a continuing need for suitable training programmes for medical staff in the general health services. Most dermatologists had good levels of knowledge and skills and more than 80% of new cases have been diagnosed in skin clinics in this province since 1990. Their participation in early diagnosis and training of staff should be strengthened.

Adult↗

PubMed2000

Cloning and sequence analysis of a Phytophthora cinnamomi gene which encodes for cinnamomin, a toxin with implications in root rot of cranberry.

We used a polymerase chain reaction (PCR) based cloning strategy to isolate cinnamomin genes from Phytophthora cinnamomi 8601, a pathogen responsible for cranberry root rot. Complete DNA sequence analysis of nine recombinant clones revealed two different classes of genes, each class consisting of genes with identical DNA sequences. Both classes of genes (Cin-1 and Cin-2) contained an open reading frame encoding a protein of 122 amino acid residues. The encoded proteins, named cinnamomin-1 and cinnamomin-2 (Cin-1 and Cin-2), were highly homologous to other proteins of the elicitin family and contained a 19 amino acid residue long signal peptide sequence. Both Cin-1 and Cin-2 proteins showed higher degree of sequence homology to the alpha-elicitins than beta-elicitins; moreover, a Val residue was found at position 13 of the putative mature Cin-1 and Cin-2 proteins. Because alpha-elicitins and beta-elicitins are known to contain a Val and a Lys residue, respectively, at this position, we concluded that both Cin-1 and Cin-2 genes from P. cinnamomi 8601 encode for alpha cinnamomins, Cin-1 and Cin-2.

Algal Proteins↗

PubMed2000

[Genetical effect of different rye chromosomes on the acid phosphatase (Acph) secretion of common wheat roots under phosphorus starvation conditions].

The effects of different rye chromosomes on Acph secretion of common wheat roots under P starvation conditions were studied by using a set of Chinese Spring-Imperial (CS-IMP) alien addition lines as materials. The Acph activity measurement results showed that P starvation is an induction factor for Acph gene expression; Different chromosomes of Imperial rye in Chinese Spring background has different effects on the secretion of Acph by corresponding addition line roots. Among them, chromosome 1R had the strongest promoting effect; The IEF diagram of Acph isozymes clearly demonstrated that chromosome 1R in rye genome carries P starvation inducible Acph gene(s).

Acid Phosphatase↗

PubMed2000

[Construction of silkworm RAPD molecular linkage map].

In this research, a RAPD linkage map of Bombyx mori was constructed with Dazao/C108 and their F2 generation. The map consists of 182 RAPD loci, of which 103 loci come from Dazao and from the first 23 linkage groups and the other 79 loci come from C108 and form the second 16 linkage groups. This map covered a total genetic distance of over 1,148.3 cM (centimorgan). It could be integrated with the SADF map of the same materials constructed in our laboratory and the corresponding RFLP linkage map.

Animals↗

PubMed2000

A burgeoning family of biological mediators: chemokines and chemokine receptors.

Chemokines are a superfamily of pro-inflammatory polypeptide cytokines that selectively attract and activate different cell types. Most of its members are small proteins that exhibit conserved cysteines in specific positions. Chemokines activate cells through their binding to shared or unique cell surface receptors which belong to the seven-transmembrane (STM), G-protein-coupled receptors (GPCRs). The large number of chemokines and chemokine receptors are indicative of the importance of these molecules in a variety of pathophysiological conditions.

Animals↗

PubMed2000

Interleukin-12 induces gene expression in interleukin-2 stimulated human T lymphocytes.

IL-12 is a critical immunoregulatory cytokine that promotes cell-mediated immune responses by inducing the differentiation of Th1 cells. To better clarify the molecular basis of IL-12 action, we compared the gene expression in human T lymphocytes activated by IL-2 and IL-12. mRNAs from T lymphocytes activated by either IL-2 alone or IL-2 plus IL-12 were transcribed into cDNAs. A differential mRNA display was conducted. As a result, differential display of five cDNA fragments was obtained. Sequence analysis suggests that they had high homology with recorded genes as found by a computer search against GenBank. Two full genes of the five fragments were cloned, which activation-induced C-type lectin and glucose transporter-like protein. Interestingly, these proteins were expressed in the T cells stimulated by IL-2 and IL-12, but not in the T cells stimulated by IL-2 alone. These results suggest that C-type lectin and glucose transporter-like protein may play an important role in the T lymphocyte activation induced by IL-12.

Base Sequence↗

PubMed2000

[The effect of adding cefobid upon the physiochemical properties of calcium phosphate cement].

This study was conducted to analyze the physiochemical properties of different mass ratio compounds of cefobid-load calcium phosphate cement(CPC). The compounds of 0%, 2.9%, 4.8% and 7.4% mass ratio cefobid-load CPC were made respectively. The setting time was observed; the compressive strength of compounds was measured by a material testing machine; the construction of compounds was observed by scanning electron microscopy(SEM) and analyzed by EIG. The results showed that both the setting time and the ratio of hole did not change obviously after the addition of cefobid, but the ultimate compressive strength decreased slowly and the results of the four groups were (21.98 +/- 1.06)MPa, (21.38 +/- 0.95)MPa, (19.22 +/- 1.11)MPa and (13.5 +/- 1.65)MPa respectively. These data indicate there is no obvious effect on the physicochemical properties of calcium phosphate cement after the addition of cefobid between 0% and 4.8%. The compounds have irregular holes and hence a good ability of compressive strength. It might be a new bone grafting material for the reparation of infection-related bone defects.

Biomechanical Phenomena↗

PubMed2000

[Cloning and expression of TTV gene fragment in E. coil and identification of the expressed protein].

OBJECTIVE: To construct a recombinant expression vector containing TTV gene fragment and identify the expressed protein. METHODS: Based on computer-aided studies, TTV ORF12 gene fragment coding protein of antigenicity was amplified by PCR from the patient serum with non-A-G hepatitis. Then the gene fragment was integrated into the multiple cloning site of pQE-30 and expressed in E coil. The expressed protein was identified by ELISA. RESULTS: The relative molecular weight of the expressed protein matches the predication and its yield was up to 22.33% of total bacterial proteins of E. coli The expressed protein was detected by ELISA. CONCLUSIONS: The recombinant vector has been constructed successfully and the expressed protein possesses antigenicity.

Adolescent↗