Search PubMed⌕ Search

Biomedical subjects

T Li

Publications and source records attributed to T Li.

At least 397 records · Page 22Linked to original sources
PubMed1996

[Preliminary study of microbiocide effect and its mechanism of electrolyzed oxidizing water].

Electrolyzed Oxidizing water (EO Water) is characterized by possessing higher oxidizing reduction potential (ORP), lower pH value and oxidizing potential. Under conditions of free organic matter, it was tested for microbiocide efficacy in laboratory. The results showed that EO water could completely kill all of the staphylococcus aureus and E. coli within 15 seconds, while for completely killing of spores of Bacillus subtilis Var. niger it would take 10 min. When it was used to destroy the antigenicity of HBsAg, 30 seconds was needed. The ORP and pH values of EO water were not obviously changed when stored in room-temperature with, airtight and light-free conditions for three weeks. Distilled water and physiological saline had little influence on the ORP and pH value of EO water, but organic matters and phosphates had greater influence upon the two values.

Bacillus subtilis↗
PubMed1996

[Study on evaluation of fetal scalp tissue pH value during labor].

OBJECTIVE: To assess the predictive value of serial monitoring fetal scalp tissue pH value (tpH) during labor. METHOD: Fifty two primipara with singleton and cephalic presentation were recruited during their active phase of labor after rupture of membrane. Their fetal scalp tpH were determined by a new type of alloy pH spiral electrode and pH-LS-1 sensor. These values were compared with the umbilical blood pH values (bpH) measured immediately after delivery. RESULTS: The fetal tpH values were significantly positive correlated with the bpH values (r = 0.822 and 0.725). The incidence of neonate asphyxia in tpH >or= 7.20 group was significantly lower than those to tpH<7.15 group. No adverse effect was observed in this study. CONCLUSION: Determination of fetal scalp tpH during labor is of predictive value and harmless fro detecting fetal distress.

Body Fluids↗
PubMed1996

Cell cycle regulation of BRCA1 messenger RNA in human breast epithelial cells.

BRCA1 was originally isolated as a gene that conferred susceptibility to early-onset familial breast and ovarian cancers. The function and regulation of this gene is presently unknown. Northern blot analyses using probes that recognize different regions of the BRCA1 cDNA revealed the presence of at least two distinct mRNA species. In synchronized normal and immortalized human mammary epithelial cells, BRCA1 mRNA levels were high in exponentially growing populations, decreased upon growth factor withdrawal, and subsequently increased again in late G1 just prior to S-phase entry. BRCA1 mRNA levels were found to be dramatically reduced in senescent normal human mammary epithelial cells and in normal human mammary epithelial cells treated with transforming growth factor beta 1. When considered together, these data indicate that expression of BRCA1 mRNA is highly sensitive to changes in growth conditions in vitro. BRCA1 proteins with apparent molecular weights of M(r) 210,000, 185,000, 160,000, 135,000, and 85,000, respectively, were detected at varying levels in all breast epithelial cells examined. Further molecular characterization of the nature and function of the different BRCA1 mRNAs and proteins should increase our understanding of this gene in the etiology of human breast cancers.

Breast↗
PubMed1996

Distinct patterns of Fas cell surface expression during development of T- or B-lymphocyte lineages in normal, scid, and mutant mice lacking or overexpressing p53, bcl-2, or rag-2 genes.

Fas is a cell membrane protein involved in programmed cell death. In normal young mice, Fas was expressed on pluripotent stem cells, multipotent progenitors, pro-T and pre-T cells, most thymocytes, and a subset of CD4 and CD8 mature T lymphocytes. In contrast, Fas expression was switched off in B-cell and myelocytic progenitors and most pro-B and a proportion of pre-B cells and was switched on again later, but this occurred only in a subset of mature B lymphocytes. A lack of bcl-2 increased the proportion of Fas+ B-lymphocyte lineage cells and Fas+ CD4+ cells and decreased the percentage of Fas- CD8+ mature T-cell subsets. Overexpression of bcl-2 reversed this pattern of Fas cell surface expression. Interestingly, lack of p53 increased the proportions of Fas-expressing CD4 and CD8 mature T-cell subsets and of Fas- B-cell precursors but decreased that of Fas- mature B-lymphocyte populations. We conclude that the expression of Fas is regulated distinctly during the development of T and B lymphocytes. Although the products of neither bcl-2 nor p53 genes are essential for Fas cell surface expression on hematopoietic cells, these repressor and effector genes, respectively, of programmed cell death affect distinct subsets of lymphoid lineage cells at different stages of lymphopoiesis. Our results suggest that distinct combinations of effector and suppressor genes of programmed cell death act on distinct cell populations and at different stages of differentiation within the same cell lineage in the hematopoietic system.

Animals↗
PubMed1996

Overexpression of Bcl-2 or Bcl-XL transgenes and photoreceptor degeneration.

PURPOSE: To test the hypothesis that overexpression of genes coding for the anti-apoptotic proteins Bcl-2 or Bcl-XL in photoreceptor cells may prevent or delay photoreceptor degenerations. METHODS: Transgenic mice were generated in which the bcl-2 or bcl-XL transgenes were expressed in photoreceptor cells under the transcriptional control of a rhodopsin gene promoter. Bcl-2 or bcl-XL transgenic mice were crossed separately to a mouse strain carrying the rd/rd mutation and to another mouse line carrying a dominant rhodopsin gene mutation; both genetic defects result in photoreceptor degeneration. Photoreceptor cell death in mice expressing one of the bcl transgenes and carrying either the rd mutation homozygously or the rhodopsin mutation heterozygously was examined by histologic and electroretinographic measurements. Bcl-2 and bcl-XL transgenic mice also were tested for possible resistance to light-induced photoreceptor damage under two different experimental conditions. RESULTS: Bcl-2 or bcl-XL transgenes were expressed in photoreceptor cells of all lines of transgenic mice. In both the rd and the rhodopsin mutant mice, expression of either bcl-2 or bcl-XL transgenes did not prevent or measurably delay photoreceptor degeneration. Apoptosis-related nuclear DNA fragmentation, as assessed by in situ labeling with terminal deoxynucleotidyl transferase, was present in 13-day-old rd/rd mouse retinas with or without transgene expression. Twelve days after exposure to 2 hours of high-intensity light, bcl-2 transgenic mice retained approximately four rows of photoreceptor cells in the central retina as compared to none in littermate controls, whereas bcl-XL transgenic mice showed no increased resistance to light damage. Expression of the bcl-2 but not the bcl-XL transgene also was associated with a reduction in rhodopsin content. CONCLUSIONS: Overexpression of bcl-2 or bcl-XL transgenes does not rescue photoreceptor cells from apoptosis caused by the two genetic mutations tested. Resistance to light damage seen in the bcl-2 transgenic mice is likely from a reduction in rhodopsin content rather than an anti-cell death activity of Bcl-2. Cell death pathways not regulated by Bcl-2 may be operative in photoreceptor degeneration.

Animals↗
PubMed1996

A novel functional polymorphism within the promoter of the serotonin transporter gene: possible role in susceptibility to affective disorders.

The serotonin transporter (5-HTT) is a candidate locus for aetiological involvement in affective disorders. Biochemical studies in suicides and depressed patients suggest that 5-HT uptake function is frequently reduced in affective illness. Furthermore, 5-HTT is targeted by widely used antidepressant drugs such as fluoxetine. We have performed an association study of a short variant of the 5-HTT-linked polymorphic region (5-HTTLPR), which restricts transcriptional activity of the 5-HTT promoter leading to low functional expression of the 5-HTT, in 454 patients with bipolar or unipolar affective disorder and 570 controls, derived from three European Centres (London, Milan and Würzburg). In all three centres, the frequency of the low activity allele was higher in patients than in controls (50% vs 45% in London, 45% vs 43% in Milan, 47% vs 40% in Würzburg). Although these differences were not individually significant, a stratified analysis of all three samples gave a significant overall odds ratio of 1.23 (95% confidence interval 1.02-1.49, P = 0.03). The excess of the homozygous low-activity genotype among the patients was even greater (odds ratio 1.53, 95% confidence interval 1.04-2.23, P = 0.02), suggesting partial recessively of the low-activity allele. Given the functional role of 5-HTT, our findings suggest that 5-HTTLPR-dependent variation in functional 5-HTT expression is a potential genetic susceptibility factor for affective disorders. If this finding is replicated, further work on genetic variants with low 5-HTT activity may facilitate the differential diagnosis of affective disorders, the assessment of suicidal behaviour, and the prediction of good clinical response to antidepressants.

Alleles↗
PubMed1996

[Angioimmunoblastic lymphadenopathy and angioimmunoblastic T-cell lymphoma].

To investigate the clinicopathological changes of angioimmunoblastic lymphadenopathy (AILD) and angioimmunoblastic T-cell lymphoma (AITL), 5 cases of AILD and AITL were analyzed by using immunohistochemistry and Polymerase chain reaction (PCR) methods. The clinical manifestations included general lymphadenopathy, hepatosplenomegaly, fever and hematologic abnormalities. The diagnosis and differentiation of AILD and AITL were depended on the histopathologic features of lymphnodes biopsy. The presence of clusters of clear cells with variable atypia and positivity of T-cell marker were the most important diagnostic criterion for AITL. PCR analysis of TCR-beta rearrangement and EBV-genome was performed on 4 of 5 cases. All of the cases showed clonal rearrangement of TCR-beta and 3 of them were EBV-DNA positive. The results suggest that AILD might be a prelymphomatous lesion, related to EBV infection with a high incidence of developing to malignant lymphoma.

Adult↗
PubMed1996

MR evaluation of the brain in central diabetes insipidus.

OBJECTIVE: To evaluate the role of magnetic resonance (MR) imaging in determining the cause of central diabetes insipidus (CDI) by using MR imaging to describe the findings in the hypothalamic-pituitary area in patients with CDI. METHODS: Thirty-one cases of clinically proved CDI were prospectively studied. A control study was also conducted in 200 normal subjects. MR imaging was performed on a 1.0 T superconductive unit with T1-weighted images obtained in the sagittal, coronal and axial planes. RESULTS: Hypothalamic-pituitary masses or structural changes were identified in 26 cases and normal structures in 5. The normal high signal intensity of the posterior pituitary lobe was absent in 29 cases, but remained unchanged in 2. In the control group, the frequency of the high signal of the posterior lobe was 93%. CONCLUSIONS: The absence of the normal high signal in the posterior pituitary lobe is closely related to the loss of hypothalamic-pituitary function. MR imaging is very sensitive in demonstrating the changes in this area in CDI and it can provide an accurate diagnosis when combined with the clinical information.

Adolescent↗
PubMed1996

[Evaluation of therapeutic effects of moist burn ointment and betadine ointment in treatment of severe burn].

In order to compare the therapeutic value of moist burn ointment (MBO) and betadine ointment in severe burns, the authors divided 30 patients with burn over 30% TBSA into two groups. In one group MBO was used, and in another group betadine was used. The result showed; 1. The difference between two groups was not great in superficial II degree burn wound. 2. MBO was less effective than betadine in deep burn wound. MBO had little antibacterial effect, wound healing was delayed, and incidences of infection, complication and mortality were higher. At the same time, MBO did not have noticeable effect in inhibiting scar hypertrophy. The authors suggest that MBO must be used with caution in severe burn patients, especially in the southern provinces where the climate is hot and humid.

Administration, Topical↗
PubMed1996

[Determination of estrogen receptor and progesterone receptor of the sinonasal malignant neoplasms].

To examine the relationship between sex steroid receptor and sinonasal malignant neoplasms, estrogen receptor (ER) and progesterone receptor (PR) were determined in 25 cases of sinonasal malignant neoplasms, 10 cases of sinonasal papillomas, 31 cases of nasal polyps and 12 cases of normal nasal mucosa. The determination of ER and PR was done by radioligand binding assay of receptors (RBAR). The results indicated that sinonasal malignant neoplasms had higher concentrations of ER and PR binding protein, while sinonasal papillomas, nasal polyps and normal nasal mucosa were found to contain lower concentration of ER and PR, and the differences were significant. (P < 0.01). It is suggested that sinonasal malignant neoplasms might depend on ER and PR.

Adolescent↗
PubMed1996

[Experimental observation on microbicidal activity of a complex glutaraldehyde disinfectant].

The microbicidal activity of a complex glutaraldehyde disinfectant was observed. The result showed that when the temperature of the test was 20 degrees C and 10% calf serum were added to the bacterial suspensions 2% diluted solution of the disinfectant for a two-minute contact could kill 99.99% of Staphylococcus aureus, and 1% diluted solution for two minutes could kill 99.99% of E. coli. The undiluted disinfectant with five-minute contact time could destroy the antigenicity of HBsAg. The undiluted disinfectant with thirty-five minute contact and 50% diluted solution with forty-five minute contact time could completely kill the spores of Bacillus subtilis var. niger under 50 degrees C. It was discovered that the germicidal concentration of the disinfectant was four times as high as the inhibition concentration and the used concentration determinal with capacity test was four times higher than as germicidal concentration when the three concentrations were compared. This result indicated that selection of suitable inactivator was very important. The practical concentration of disinfectant should be decided under the basis of the result from capacity test.

Animals↗
PubMed1996

[A clinical study of multistage isoproterenol tilt table test for patients with unexplained syncope].

The purpose of the present study is to evaluate the clinical usefulness of multistage isoproterenol tilt table test (MITTT) in patients with syncope of unexplained origin. 35 patients (mean age 40 +/- 8 years) with syncope of unknown origin and 20 patients (mean age 49 +/- 7 years) with sinus bradycardia as controls were subjected to successive MITTT (4 stage). 28 of the 35 patients with syncope of unknown origin who underwent the MITTT developed syncope (80% positive response). Only 2 of the 20 patients with sinus bradycardia developed syncope (10% positive response). There was a highly significant statistical difference in positive response between the two groups (P < 0.001). If MITTT was combined with isoproterenol test (< or = 3 micrograms/min), positive response was obtained in 95% and only 5 minutes were sufficient to induce positive response. The mean heart rate-pressure product accurately indentified both positive and negative test results (positive predictive value < or = 1.2 x 10(3) kPa/min, negative predictive value > 1.3 x 10(3) kPa/min). These results suggest that MITTT is a valuable provocative test for vasovagal syncope.

Adolescent↗
PubMed1996

Preparation of monoclonal antibodies against chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase and their effects on enzyme activities.

The effects of the monoclonal antibodies (McAbs) directed against chicken liver 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (6PF-2-K/Fru-2, 6-P2ase) on the structure and function of the enzyme were studied. Using chicken liver 6PF-2-K/Fru-2, 6-P2ase as antigen, 7 clones of monoclonal antibodies specifically binding with the antigen were obtained. The epitopes of the antigen recognized by the 6 McAbs localized on the fructose-2, 6-bisphosphatase domain of chicken liver 6PF-2-K/Fru-2, 6-P2ase, and the other (H2) are on the 6-phosphofructo-2-kinase domain. All of the 7 McAbs could activate the kinase activity of the bifunctional enzyme by twofold and had a similar effect on the bisphosphatase activity of the bifunctional enzyme which resulted in a fourfold increase of the bisphosphatase activity of the bifunctional enzyme. However, the McAbs did not affect the activity of the separated fructose-2, 6-bisphosphatase domain. The results suggested that the Fru-2, 6-P2ases in the bifunctional enzyme and in the separated bisphosphatase domain were in two different conformation and activity states.

Animals↗
PubMed1996

[Observation on TXB2 and 6-keto-PGF1 alpha in serum of patients with cor pulmonale].

To know the changes of TXA2 and PGI2 in serum of patients with cor pulmonale, the levels of their stable metabolites TXB2 and 6-keto-PGF1 alpha in serum were examined in 28 patients with cor pulmonale during alleviation, 29 patients with cor pulmonale during exacerbation before and after treatment and 10 healthy subjects. TXB2 and 6-keto-PGF1 alpha were 109.74 +/- 56.14 ng/L and 54.76 +/- 35.62 ng/L respectively in healthy subjects; TXB2/6-keto-PGF1 alpha = 2.004. The TXB2 level of patients with cor pulmonale at every stage was higher than that of healthy subjects (P < 0.05-0.01). Patients with cor pulmonale during exacerbation had the highest TXB2 level of 709.22 +/- 354.49 ng/L, which decreased to 408.24 +/- 289.41 ng/L (P < 0.05) after treatment with traditional Chinese medicine combined with western medicine and the decreased level as such was not significantly different from that during alleviation (333.14 +/- 324.14 ng/L). The 6-keto-PGF1 alpha level in patients with cor pulmonale at every stage was not significantly different from that of healthy subjects. Since TXB2 increased, the value TXB2/6-keto-PGF1 alpha of patients with cor pulmonale was greater than that of healthy subjects. It is most likely that chronic hypoxia and hypercapnia lead to prostaglandin release in the lung of patients with cor pulmonale; hypoxia and hypercapnia become more severe during exacerbation resulting from infection; which lead to increased prostaglandin release, then high TXB2 level ensue as the result. TXB2 decreases after amelioration of hypoxia during treatment. But the change of 6-keto-PGF1 alpha is not obvious.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

[Studies on some characteristics of a strain of mink infectious enteritis virus].

A strain of mink infectious enteritis virus that was isolated from the east district of China can be bred on FK cell. Concentrated viruses were purified by using Sepharose-4B chromatography. The size of the virus was about 20-22 nm by electron microscope. Viral nucleic acid was extracted from pure virus by using SDS-protease K-Phenol. Tests with diphenylamine, acridine orange and the curve of thermal dentuation, etc. showed that the virus had a single-stranded DNA. The molecular weight of the ssDNA was from 1.5 x 10(6) to 2.0 x 10(6) determined by length of the virul nucleic acid.

DNA, Single-Stranded↗
PubMed1996

[An experimental animal model study of HCMV].

This Paper is a study of animal model on the Kunmin and BALB/C mice infected HCMV-AD169. The death-rate showed a marked higher BALB/C mice (28.75%) than the kunmin mice. The Kunmin mice Percentage of diseased (94.74%) higher than BALB/C mice. Brian tissue of two groups mice that pathological changed was equal by HCMV infected.

Animals↗