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Biomedical subjects

D Li

Publications and source records attributed to D Li.

At least 595 records · Page 33Linked to original sources
PubMed1997

[Serum tumor necrosis factor-alpha levels in non-Hodgkin's lymphoma patients and its relationship to prognosis].

OBJECTIVE: To explore the relationship of tumor necrosis factor-alpha (TNF alpha) with non-Hodgkin's lymphoma (NHL) and to evaluate clinical implication of serum TNF alpha. METHODS: Serum TNF alpha levals were measured by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) in 76 NHL patients. Survival analysis was performed. RESULTS: Serum TNF alpha was increased in 55% newly diagnosed patients, and dropped to normal level on remission but increased again on relapse. Elevated TNF alpha levels of patients at diagnosis were significantly associated with Ann Arbor stage, bulky tumor and B symptoms, but weren't correlated to serum lactic-dehydrogenase (LDH) nor to beta 2-microglobulin (beta 2-MG). The survival period of patients with elevated TNF alpha levels was shorter than that of patients with normal TNF alpha levels. CONCLUSION: Elevated serum TNF alpha level is associated with high tumor burden and can be used as a prognostic marker.

Adult↗
PubMed1997

[Application of TLC to tannin measurement].

There has been little report on the use of in measuring tannin in traditional Chinese medicinal preparations by TLC. Gallic acid, the decomposd product of tannin, was in bright yellow and green color, showing a strong specificity. The measurement of gallic acid can provide reliable indexes for quality assay of TCM preparations.

Chromatography, Thin Layer↗
PubMed1997

[Interactions among stimulators of bone resorption in organ culture].

The labeled 45Ca long bone shafts of 19 day fetal rats in organ culture was used in the study. Actions and interactions between various concentrations of LPS, TNF, LTA and PGE were quantitatively analysed by sample channels ratio method. The results indicated that they could all induce bone resorption in organ culture and show significance of differences assessed using student's test (P < 0.05). Interacts between LPS and TNF, LPS and PGE, TNF and PGE were greater than the sum of the individual responses when added together (the expection value), LPS and LTA, TNF and LTA were equal to the expection value, but LTA and PGE were less than the expection value. The result supported that the interactions among these stimulators of bone resorption were important in the pathogenesis of bone loss in periodontal disease.

Animals↗
PubMed1997

[Study on effects of combined hearing protector on communication quality and noise protection].

To study the communication quality and the protection effects of single protector and the combined ones, sound attenuation experiments and the communication experiments were conducted in 14 male subjects. The results showed that the sound attenuation of combined protectors were 13 dB or 6dB more than that of single earplug or earmuff respectively, and combined protectors could avoid sound attenuation caused by the harmonics on some frequency bands in single one. After combined usage, the single protector reduced the distortion which came from the overload of hearing organs and maintained the communication quality. The combined protector is an effective hearing protection device in high noise environment in aerospace field.

Communication↗
PubMed1997

[Detection of CD59(-) blood cells in patients with aplastic anemia].

OBJECTIVE: To detect paroxysmal nocturnal hemoglobinuria (PNH) clone in aplastic anemia (AA) patients. METHODS: Flow cytometric technique along with antibodies against CD59 was used to estimate the amount of GPI-P deficient cells, characteristic of PNH abnormalities. RESULTS: Among 23 cases of AA studied, 13 possessed no excessive percentage of CD59(-) cells in peripheral PMNs and RBCs. Eight of these 13 cases underwent bone marrow examination, and no increase of CD59(-) mononuclear cell (MNC) was found either. Three other AA patients had slightly increased amount (> 5%) of CD59(-) cells in both peripheral blood and bone marrow. In seven cases, percentages of CD59(-) cells were normal in peripheral RBCs and PMNs but increased in bone marrow MNCs. CONCLUSION: Measurement of CD59(-) cells in periperal blood and bone marrow by flow cytometry may serve as the best way of detecting PNH clone in AA, and thus could be used for the early diagnosis of AA-PNH syndrome.

Anemia, Aplastic↗
PubMed1997

[Study on serum soluble interleukin-6 receptor levels in patients with malignant hematological diseases].

OBJECTIVE: To explore the clinical implication of soluble interleukin-6 receptor(sIL-6R) in patients with malignant hematological diseases. METHODS: Serum levels of sIL-6R in 26 multiple myeloma (MM), 34 acute leukemia (AL) and 17 non-Hodgkin's lymphoma (NHL) patients before and after chemotherapy and 20 normal controls were measured by immunoenzymetic assay. RESULTS: Serum levels of sIL-6R in MM and B-ALL patients at diagnosis were significantly higher than that in normal controls (P < 0.001, and P < 0.01, respectively), while the levels in ANLL, T-ALL and NHL patients were normal. Serum beta2 microglobulin and creatinine levels in MM patients with elevated serum sIL-6R were higher than that in patients with normal sIL-6R levels(P < 0.001, and P < 0.05, respectively). Serum sIL-6R levels did not relate to clinical stages. Serum lactic-dehydrogenase (LDH) levels in B-ALL patients with elevated sIL-6R were higher than that in patients with normal sIL-6R levels (P < 0.05). Serial measurement of serum sIL-6R in MM patients showed a good correlation with serum M-protein and plasma cell percentage in bone marrow. CONCLUSION: Serum sIL-6R levels were significantly increased in MM and B-ALL patients, and it is a predictive factor for responsiveness to chemotherapy and an indicator of disease activity.

Adult↗
PubMed1997

[Determination of thiodicarb by reversed-phase high performance liquid chromatography].

In this paper, a method for determination of thiodicarb by reversed-phase high performance liquid chromatography (RP-HPLC) is presented. Analysis was performed on a 250 mm x 4.6 mm i.d. octadecylsilica (ODS or C18) bonded phase column in 8 minutes. Methanol/water mobile phase was used. Ultraviolet detector was used for detection at 232 nm wavelength. The internal standard method (using dimethyl phthalate as the internal standard) was employed. The linearity of the method was verified. The relative standard deviation (RSD) of determination for 75% thiodicarb wetted-powder was 0.18%. The average recovery was 99.89%. The method has been used for analysis of pesticide products and control of production.

Chromatography, High Pressure Liquid↗
PubMed1997

[Determination of gamma-aminobutyric acid and glutamic acid in human cerebrospinal fluid by high performance liquid chromatography].

Gamma-aminobutyric acid (Gaba) and glutamic acid (Glu) are believed to be the major neurotransmitter. Levels in cerebrospinal fluid (CSF) may reflect their metabolism in various neurotic and psychiatric diseases. Measurements of Gaba and Glu in body fluids will help to elucidate their metabolic role and diagnostic value. In the present work, the concentrations of glutamic acid and gamma-aminobutyric acid in human cerebrospinal fluid were determined by reversed-phase high performance liquid chromatography using pre-column derivatized with dansyl chloride and UV detection at 254 nm. The mobile phase was A:CH3OH and B: THF/CH3OH/0.05 mol/L NaAc (pH 6.2) (5/75/420, V/V) with gradient elution. The flow rate was 1 mL/min. CSF samples were deproteinizated with methanol. After centrifugation at 15000 r/min for 10 min, the supernatant was introduced into a screw-capped vial and evaporated to near dryness at 80 degrees C. Derivatization was carried out by the addition of 250 microL of bicarbonate solution (pH 9.8) and 250 microL of dansyl chloride solution (4 g/L) followed by heating at 40 degrees C water bath for 30 min. Extraction was performed with 300 microL of ethyl acetate and the organic layer separated was dried at room temperature under nitrogen. The dry residue was dissolved and injected into the HPLC system. The linear range of the method was 5-1000 micromol/L (r = 0.9988) for Glu and 1-600 micromol/L (r = 0.9984) for Gaba. The lower limit of detection were 0.002 micromol/L and 0.001 micromol/L respectively. The recoveries were 96.9%-98.8% and 97.5%-98.8% and the coefficients of variation of peak height measurements were 2.2%-3.4% and 3.8%-5.6% respectivery. The method enables a simple, rapid and reproducible quantification of Glu and Gaba neurotransmitter.

Chromatography, High Pressure Liquid↗
PubMed1997

MR imaging of renal function.

MR imaging has advantages over both computed tomography and nuclear scintigraphy for assessing renal function, because it combines high spatial resolution with information on perfusion and function. A further advantage is the lack of ionizing radiation. Quantitation of flow rate by phase contrast in the renal arteries and veins has the potential to provide estimation of renal blood flow, which could prove useful in a number of clinical situations, especially for studying renal vascular disorders and the effects of treatment, and for assessing renal transplants. Evaluation of renal perfusion with MR imaging has become feasible with the development of rapid data acquisition techniques, which provide adequate temporal resolution to monitor the rapid signal changes during the first passage of the contrast agents in the kidneys. More recently, magnetically labeling water protons in blood flowing into kidneys has been used to noninvasively quantitate regional measurement of cortical and medullary perfusion. Other techniques being investigated with MR imaging for assessment of renal function include diffusion imaging GFR estimation and blood oxygenation level dependent imaging to evaluate intrarenal oxygenation levels.

Animals↗
PubMed1997

International clinical trials of HIV vaccines: II. phase I trial of an HIV-1 synthetic peptide vaccine evaluating an accelerated immunization schedule in Yunnan, China.

A Phase 1, double-blind, placebo controlled trial was conducted in Longchuan County, China, to evaluate the safety and immunogenicity of a prototype HIV-1 synthetic peptide vaccine in a target population at risk for HIV infection, and to establish the infrastructure for future large-scale HIV vaccine efficacy trials. Subjects were randomly assigned to receive 100 microg or 500 microg of vaccine or alum placebo, and were given three injections at an accelerated 0, 1, and 2 month schedule. The vaccine was well tolerated with no significant local or systemic reactions observed in any subjects. Fifty-five percent (100 microg dose) and 64% (500 microg dose) of subjects who received the vaccine produced binding antibody to the immunogen as determined by ELISA. However, HIV-1 (MN) neutralizing antibody was detected in only 23% (3/13) of subjects with detectable HIV-1 specific binding antibody. It was concluded that this prototype HIV-1 synthetic peptide vaccine was well tolerated, safe and immunogenic, and that a 0, 1, 2 month schedule was not as effective in stimulating HIV-1 specific neutralizing antibodies compared with previous trials utilizing a 0, 1, 6 month schedule. Finally, this trial demonstrated that well-designed HIV vaccine trials can be performed at this clinical trials site in Yunnan, China, and that this site should be considered for conducting larger safety, immunogenicity and efficacy trials of candidate HIV vaccines.

AIDS Vaccines↗
PubMed1997

Biochemical and immunohistochemical characterization of human type XIX defines a novel class of basement membrane zone collagens.

Nineteen types, the product of 33 genes, comprise the collagen family of proteins. Types I, II, III, V, and XI constitute the fibrillar collagens, whereas types IV, VI to X, and XII to XIX represent the structurally diverse, nonfibrillar members. Type XIX collagen was discovered from the sequence of rhabdomyosarcoma cDNA clones. The type XIX chain consists of 1142 amino acids that contribute primarily to a unique five subdomain triple-helical region. To characterize the protein, to determine the tissue distribution, and to provide some insight into its function, we generated two type XIX-specific polyclonal antibodies. One was directed against a recombinant molecule containing amino-terminal sequences, and the second was derived from a synthetic peptide corresponding to most of the short carboxy terminus. These antibodies were used in immunoblot assays of rhabdomyosarcoma cell/matrix homogenates to identify a 165-kd disulfide-bonded and bacterial collagenase-sensitive protein. Immunohistochemical analysis of type XIX collagen was performed for human skeletal muscle, spleen, prostate, kidney, liver, placenta, colon, and skin. In contrast to Northern blot hybridizations, which showed very low levels of the 12-kb transcript in few tissues, the protein was found in all tissues examined. The type XIX collagen distribution was restricted to vascular, neuronal, mesenchymal, and some epithelial basement membrane zones, which is similar to the profile recently established (Ref. 8) and further extended here for type XV collagen. Nevertheless, localization of type XIX exhibited significant differences from type XV collagen that were particularly evident in the kidney, liver, and spleen. This report, in conjunction with the type XV results and other studies of type XVIII collagen, indicates the existence of a new collagen subgroup founded on their widespread presence in basement membrane zones regardless of chain homology. In addition to their role in basement membrane-stromal interactions, the pronounced vascular association suggests involvement of these related collagen types with angiogenic and pathological processes.

Basement Membrane↗
PubMed1997

[Study on the recognition and evolutionary genetics of the courtship song of species in Drosphila nasuta species subgroup].

The subgroup of Drosophila nasuta consists of 14 species, subspecies and taxa. It has a wide distribution in area of Indo-Pacific Ocean. The courtship song of species in nasuta subgroup is recorded for the first time in the paper. Some parameters of temporal pattern of pulse song were measured: the inter burst interval (IBI), the interpulse interval (IPI), the length of a pulse train (PTL), the number of pulses in a train (PN), the length of a pulse (PL) and the length of a cycle (CL). Computer analysis techniques were used to make spectral analysis of sine song. A three-dimensional power spectra of the sound was made. In this subgroup, the male of D. pulauna and Taxon-F didn't produce any sound signals during courtship, suggesting that the visual stimuli play an important role in mating process. By analysing the courtship sound signals of other species, subspecies and taxa, the sounds produced by courting male could be described as pulse song or as sine song. By studying the sounds of intra- or interspecific F1 hybrids we have found that the parameters of the temporal pattern of pulse song, for example, the mean value of IPI is controlled by X-linked and autosomal polygene and the sine song frequency is predisposed to the maternity. The phylogenetic tree of the subgroup is constructed based on the temporal pattern of the pulse sounds in different species, subspecies and taxa. The relationship within the members of the Drosophila nasuta subgroup is discussed.

Animals↗
PubMed1997

[Targeting delivery of liposomal adriamycin by intra-lymphatic infusion].

OBJECTIVE: To assess the feasibility of delivering liposomal adriamycin (lipo-ADM) to the regional lymph nodes via intralymphatic infusion in a rabbits model. METHODS: The plasma and tissue ADM levels were measured by high performance liquid chromatography (HPLC) at 0.5 hour, 1 hour, 6 hours, 12 hours, 1 day, 7 days, 14 days, 28 days. RESULTS: The maximum ADM level (Cmax) in the lymph nodes of lipo-ADM was 91.23 micrograms/g, which was 2 times higher than that of the free-ADM group. The area under the ADM concentrations-time curve (AUC) of the regional lymph nodes of lipo-ADM and free-ADM was 138.34 micrograms/day x g-1, 31.86 micrograms/day x g-1 respectively (P < 0.01). The pathological features showed that the lipo-ADM group had more microabscess, necrosis and fibrosis in the lymph nodes than those of the free-ADM group. The histological changes of heart were absent or slight in the lipo-ADM group. CONCLUSIONS: lipo-ADM has a high affinity for lymphatic tissue. Intralymphatic infusion of lipo-ADM may be useful for the treatment of lymphnode metastasis in ovarian cancer.

Animals↗
PubMed1997

[Blocking action of tetrandrine on the cell proliferation induced by PDGF in human lung fibroblasts and liver Ito cell of rats].

OBJECTIVE: To investigate the mechanism of hepatic fiberosis, the effects of platelet-derived growth factor (PDGF) on cell proliferation activity and collagen synthesis in human lung fibroblasts (HLF) and Ito cells of rat liver as well as the blocking action of tetrandrine on the cell proliferation induced by PDGF. METHODS: The Ito cells were separated from liver of rats by using the perfusion of collagenase and density pradient centrifugation. The cell proliferation was observed with the incorporation method of H-TdR and 3H-L-proline. RESULTS: Under condition of cell culture with 1% serum, PDGF could significantly enhance DNA synthesis, cell proliferation and collagen synthesis, which increased in degree with a rising of concentration of PDGF. This occurred in culture without serum, but under the same condition, if PDGF was applied together with insulin-like growth factor (IGF), it enhanced cell proliferation. The result also showed that the dose of tetrandrine below the level of inhibiting cell DNA synthesis could antagonize the stimulation action of PDGF on cell proliferation and collagen synthesis. CONCLUSION: Tetrandrine plays the blocking action in the promoting cell proliferation induced by PDGF.

Alkaloids↗
PubMed1997

[Effects of captopril on the tissue nitric oxide synthase in off spring from treated pregnant SHRs].

OBJECTIVES: To further clarify the anti-hypertensive mechanism of captopril and explore a new method for earlier prevention and treatment of hypertension, we studied the effects on tissue nitric oxide/nitric oxide synthase (NO/NOS) of the descendants of spontaneously hypertensive rats (SHRs) by earlier captopril treatment. METHODS: After the pregnant SHR was treated by captopril (100 mg.kg-1.d-1), the systolic blood pressure (SBP), NOS activity and expression of inducible and constitutive NOS (iNOS and cNOS) in brain cortex, renal cortex, heart ventricle of their descendant were detected by tail-cuff sphyg-momanometer, liquid scintillation and reverse transcription-polymerase chain reaction method respectively. RESULTS: Compared with that of non-treated SHR, SBP of treated SHR was decreased (P < 0.01) and NOS activity of renal cortex, heart ventricle, iNOS expression of brain cortex, cNOS expression of renal cortex, heart ventricle significantly increased (P < 0.05). CONCLUSION: The results suggested that earlier captopril treatment could increase NOS activity and expression in different tissues of SHR, which might be a new anti hypertensiven mechanism.

Angiotensin-Converting Enzyme Inhibitors↗